DNA Based Biosensor in Diagnosis: A Review

DNA Based Biosensor in Diagnosis: A Review The advent of fast and easy DNA testing has given the space for the Science to develop small and easy-to-handle equipments called Biosensors. DNA based biosensors have been proven very useful and are accorded with much importance in detecting the target genes responsible for diseases. This article enlists different types of biosensors, their basic principle of operating system, the preparation of DNA microarrays, lab-on-a-chip and their role in diseases diagnosis. DNA biosensors provide swift, sensitive, selective, simple and economical detection of DNA hybridization. New strategies for DNA biosensor are enumerated and are used meticulously in recent trends and for future directions. Carbon nanotubes (CNTs) amplify the electrochemical signal when used with DNA hybridization. Electrochemical, piezoelectric, SPR, optical DNA biosensors are used to detect various viruses like hepatitis virus, HCMV, HIV, orthopox virus etc. and also for the diagnosis of various diseases like cancer, tube rculosis, COPD, genetic diseases (sickle cell anemia i.e. due to single point gene mutation), cystic fibrosis, diabetes etc. The methodologies of detecting such diseases using different types of DNA based biosensors and gene chips are described in this article. PCR free DNA chips, cell- omic sensors and nanosensor are emerging tools in the field of diagnosis. Recent advances in developing such devices provide myriads of new opportunities for DNA diagnostics. Introduction A rapidly developing area of biotechnology arousing intense scientist interest is that of biosensor. Biosensor has become popular in the field of food analysis [1], bioterrorism [3], environmental [2-3] and in the area of human health monitoring and diagnostics [4-6]. Recent advances are being mad in all areas of biosensors technology. Presently, most fascinating and prospective sensors are immunosensors based on affinity reactions between antibody and antigens and DNA biosensors based on the hybridization between DNA probes and their complementary DNA strands. In general, biosensor is an analytical device which employs biological recognition properties for a selective analysis. Such sensors combine a biological element with a physiochemical transducer for the electronic signal output which is proportional to the concentration of analytes [7]. A basic biosensor assembly includes a biological element, transducer and detector. The sensing material may be antibodies, enzymes, whole cell or nucleic acids that form a recognition layer which is integrated with the transducer via immobilization by cross linking, adsorption or covalent binding. Transducers may be amperometric (measuring the current at constant potential) [8], potentiometric (measuring the potential at constant current) [9], piezoelectric (measuring the changes in mass), thermal (measuring the changes in temperature) [10] or optical (detects changes in transmission of light) [11]. The interaction between the analyte and the biological material, used in biosensors may be of two types: a) Bioaffinity sensors: depend on the selective and specific attachment of the target molecule to the surface-attached ligand partner (e.g. antibodies, nucleic acids). b) Biocatalytic sensors: an immobilized enzyme is used as a tool to recognize the target substrate (sensor strips with immobilized glucose oxidase used for personal monitoring of diabetes). A number of steps, much labor, time and costly instruments are required in usual analytical technique whereas biosensors are economical, fast and simple and can be used in small laboratories and hospitals of remote areas which are devoid of sophisticated instruments facilities. DNA Biosensors Nucleic acid recognition process is the basis of DNA Biosensors. These are being developed with a rapid pace with an ambition for inexpensive testing for genetic and infectious disease and for detecting DNA damage and interactions. The study of gene polymorphisms and the analysis of gene sequences play a fundamental role in rapid detection of genetic mutations, opens up new opportunities for reliable diagnosis even before any symptoms of a disease appear. Thus recent advances in developing such devices offer the opportunities for DNA diagnostics. DNA biosensors are made by immobilizing single stranded (ss) DNA probes on different transducers for measuring the hybridization between the DNA probes and their complementary DNA strands [12-13]. The current methods to identify specific DNA sequence in Biological samples depends on the isolation of double stranded (ds) DNA and further polymerase chain reaction (PCR) to amplify the target sequence of DNA. The PCR product is then subjected to electrophoresis or adsorbed onto a suitable membrane and exposed to a solution containing DNA probe. Surface Chemistry and Biochemistry The immobilization of DNA probe onto the transducer plays an important role in the performance of the DNA Biosensor. It should be in well-defined probe orientation and should be readily accessible to the target. The mode of immobilization is the determining factor for the type of environment of probes that are immobilized at the solid surface. On the basis of nature of physical transducer, various schemes can be opted for the DNA probes attachment to the surface such as thiolated DNA utilisation for self binding onto gold transducers, the formation of a complex by the use of biotylated DNA with a surface-confined strepavidin or avidin, covalent binding to the gold surface through functional alkanethiol-based monolayer and coupling covalently (carbodiimide) to the functional groups on carbon electrodes or adsorption onto carbon surfaces. Introduction of peptide nucleic acid (PNA) has paved way for many exciting and new opportunities to DNA biosensors. Peptide Nucleic Acid is a DNA mimic, the only difference is that the sugar-phosphate bone is replaced by a pseudo-peptide one. Like use of surface-confined PNA recognition layers provides remarkable sequence specificity on DNA biosensors and offers other advantages. DNA dendrimers may also be utilized for imparting extreme sensitivity onto DNA Biosensors. By shape, these are tree-like superstructures which possess numerous ss arms that are able to hybridize to their complementary DNA sequence. The immobilization of these dendritic nucleic acids onto physical transducer gives an amplified response [14]. Recent advances in the field of biomolecular techniques may be used to design new generation miniaturized biosensor. Types of DNA based Biosensors 1. Optical Type Fiber optics Biological Element Laser Interferometry Transducer DNA Advantages Optical fiber Highly sensitive Disadvantages Expensive equipment and not portable turbidity interference 2. Electrochemical Type Potentiometric Biological Element Conductometric Transducer Amperometric DNA Advantages Carbon paste electrodes Cheap, Fast Limitations Interference of highly buffered solution 3. Piezoelectric Type DNA Biological Element Quartz Crystals Advantages highly sensitive, Fast 4. DNA chips DNA Quantitative Optical DNA based Biosensor Optical methods are the most commonly used for the detection of analytes. DNA optical biosensors are based on a fiber optic which transduces the emission signal to a fluorescent label and that can carry light from one region to another through a series of internal inflections. The methodology of fiber-optic DNA bio-sensors involves placing of a single stranded DNA probe at the ending-site of fiber and assessing the fluorescent changes resulting from the combination of a fluorescent indicator with the double stranded DNA hybrid [15 16]. The first DNA optical bio-sensors were developed by Krull and Co workers using fluorescent indicator ethidium bromide. A fiber-optic DNA sensor array was developed by Watts group for the detection of multiple DNA sequences at one time [17]. The hybridization of fluorescent labeled complementary oligonucleotides was assessed by observing the increase in fluorescence. A real label free optical detection of DNA hybridization can be offered by a different type of optical transduction based on evanescent wave devices. The different types of optical biosensors include: 1.1 Surface Plasmon Resonance (SPR) It is a quantum optical electrical phenomenon based on the interaction of light with metal surface. Only at specific resonance wavelength of light, the energy carried by photons of light is transferred to packets of electrons (photons) on a metal surface [17]. These biosensors depend on change in surface optical properties (change in resonance angle because of alteration in interfacial refractive index) which results from the surface binding reaction. Thus, these devices integrate the simplicity of SPR with the sensitivity and specificity of wave guiding devices. The SPR signal that is expressed in resonance units is therefore a measure of mass concentration at the senor chip surface [18-20]. 1.2 Molecular Beacons (MBs) MBs are oligonucleotides possessing a stem and loop structure that are labeled with a quencher at one end and a fluorophore on the other end of the stem that converts into fluorescent upon hybridization. MB probes possess high sensitivity and specificity and direct monitoring capability. A biotinylated molecular beacon probe was developed to prepare a DNA sensor using a bridge structure. MB was biotinylated at quencher site of the stem and linked on a glass through streptavidin that act as a bridge between MB and glass matrix. The fluorescence change was measured by confirmation change of MB in the presence of complementary target DNA [21-23]. Quantum Dot It is an ultra sensitive nanosensor based on fluorescence resonance energy transfer (FREET) that can detect very low concentration of DNA. In these neon sensors, quantum dots (QDs) are linked to specific DNA probes to capture target DNA. The target DNA strand binds to a fluorescent dye (Fluorophore) labeled reporter strand and thus forming FREET donor acceptor assembly. Quantum dot also functions as target concentrator as well as FREET energy donor [24]. DNA nanosensor contains two target specific DNA probes i.e. reporter and capture probe. The reporter probe is labeled with fluorophore whereas capture probe is labeled with biotin that binds with streptavidin conjugated with QD [25]. The fluorophore acceptor and QD donor in close proximity produce fluorescence from acceptor by means of FREET on illumination of the donor. The presence of target DNA is indicated by the detection of acceptor emission. The un-hybridized probe does not give fluorescence. The CdSe Zns core shell nanocrys tal can be used as donor and Cy5 (fluorophore) as acceptor for developing QD based DNA nanosensors [25]. For this type of optical bio sensors fluorescent dyes used as standard labels are very expensive and can rapidly photo bleach. An alternate used is chemiluncinscence format, which overcomes the use of fluorescent dyes. A Fiber-optic DNA biosensor array A new method of preparing the fiber-optic DNA biosensor and its array for the simultaneous detection of multiple genes is described. The optical fibers were made into fiber-optic DNA biosensors by adsorbing and immobilizing the oligonucleotide probe on its end but were first treated with poly-l-lysine. The fiber-optic DNA biosensor array was well prepared by assembling the fiber-optic DNA biosensors in a bundle in which each fiber carried a different DNA probe. Hybridization of fluorescent- labeled cDNA of Rb1 gene, N-ras gene and Rb1 p53 gene to the DNA array was monitored CCD camera. A good result was achieved [61]. 2. Electrochemical DNA Bio sensors These are very useful devices for sequence specific biosensing of DNA. The inherent miniaturization of such devices and advance micro fabrication technology make them excellent tool to diagnose DNA. DNA hybridization is detected electrochemically by monitoring the current response at fixed potential. Detection of hybridization is also commonly done through the increased current of a redox indicator or from other changes induced by hybridization in electrochemical parameters such as capacitance or conductivity [26-28]. The discovery of carbon nano tubes (CNTs) plays an important role in development of electrochemical DNA sensors. Various CNT based electrochemical are developed because the combination of unique electrical, thermal, chemical, mechanical and 3-D spatial properties of CNTs with DNA hybridization offers the possibility of creating DNA bio sensors with specificity, simplicity, high sensitivity and multiplexing. Two major groups in which CNTs divided are single walled CNTs (SWCNTs) that are comprised of a single graphite sheet rolled with a tube and multi walled CNTs (MWCNTs) that are concentric closed graphite tubes [29]. CNT enables immobilization of DNA molecules and also used as powerful amplifier to amplify signal transduction of hybridization [30]. Two types are generally used to immobilize the CNT on electrodes aligned and non-aligned. Two approaches are generally used for the immobilization of bio molecules onto CNTs that are non covalent attachment (physical absorption) and covalent binding (some cross linker agents (1-ethyl 3-3 dimethylaminopropyl) carbodilimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS)] or affinity binding (avidin biotin interaction). CNT also act as novel indicator of hybridization. The application of arrayed CNT into DNA chip requires small amount of sample and development of CNT base biosensor has an important role in DNA based diagnostics in hospitals or at home [30]. Various methods are used for immobilizations step i.e. for attaching the DNA probe onto the solid surface that are (a) the use of thiolated DNA probe for self assembled monolayers (SEM) onto gold transducers by covalently bonding to the gold surface through functional alkanethiol based monolayers.(b) Attachment of biotinylated DNA probe through biotin avidin interaction on electrode surface for e.g. avidin modified polyaniline electro chemically deposited onto a Pt disc electrode for direct detection of E. Coli by immobility a 5 biotin labeled probe using a differential pulse Voltametric technique in the presence of methylene blue as an DNA hybridization indicator [31,32]. The electrochemical DNA biosensors may be labeled free and labeled based. Label Free In this direct detection technique the target molecule does not need to be labeled [27]. The elimination of labeling steps simplifies the readout the speed and ease of nucleic acid assays. Thus recently increased attention has been accorded to new label free electrochemical detection schemes. There is a possibility in exploiting the changes in DNAs intrinsic electroactivity (Guanine oxidation peak of hybridization). To deal with the drawbacks of the probe sequences i.e. absence of G, guanines were substituted by inosine residues (pairing with C) and detection of hybridization was done through the target DNA guanine signal. The change in the guanine oxidation and intrinsic DNA redox signals detects the chemical and physical damage [33]. Label Based In label based electrochemical biosensor specific organic dyes, enzymes or metal complexes are used for hybridization detection. Redox active molecules such as methylene blue, dacinomycin that is inserted between the dsDNA and gives signal which is used for detecting hybridization [26] (e.g. of two commercialized DNA chips based on redox active molecules are eSensor TM produced by Motorola life sciences [34], Inc. and Genlyser TM by Toshiba)[35]. Piezoelectric DNA Biosensor These are the mass sensitive devices rely on quartz crystal that oscillate at a defined frequency when oscillation voltage is applied. Increased attention has been given to piezoelectric method due to their simplicity, cost, sensitivity and real time label free detection. The quartz crystal microbalance is an extremely sensitive piezoelectric device that monitors the hybridization events. These biosensors DNA probe is immobilized on the surface of oscillation crystal. The increased mass due to hybridization reaction results in change in oscillating frequency [36-37]. A Piezoelectric sensor for determination of genetically modified soyabean roundup ready [RR soyabean] by immobilizing probe related to 5-enolpyrllvylshikimate 3-phosphate synthase (EPSPS) gene onto gold piezoelectrodes [38]. For detecting a point mutation in a human gene (apolipoprotein-E polymorphism) a combination of DNA piezoelectric biosensor and PCR was developed by immobilizing biotinylated probe on the streptavidin coated gold surface of quartz crystal. The hybridization probes with complementary, non-complementary and mismatched DNA of synthetic as well as amplified PCR samples from human blood DNA was taken out and the device was able to distinguish polymorphism [39]. Colorimetric or Strip type DNA sensor Using these sensors the direct detection of DNA hybridization is possible [40-42]. The dry-reagent strip type biosensor has been developed for visual detection of double stranded DNA within a short time [43]. Oligonucleotides conjugated gold particle is used as probe. The main advantage of these biosensors is not requiring any instruments, multiple incubation and washing steps. Integral part of strip consists of gold particles, with oligo (dT) attached to their surface. Biotinylated PCR products are hybridized with poly (dA) tailed oligo, switched to the top of strip and immersed in the appropriate buffer. With the migration of buffer in upward direction, the nanoparticles that are linked through target DNA through poly (dA/dT) hybridization are rehydrated. Immobilized streptavidin then capture the hybrid in the controlled zone of the strip. The test is 8-10 times more sensitive than ethidium bromide in agarose gel electrophoresis. The detection limit is abysmally low of 2 fmol of amplified DNA products. DNA Biochips Microarrays, DNA arrays, gene chips or biochips are same terminology often being intermixed. DNA microarrays are small, solid supports which themselves are usually microscopic slides, but can also be silicon chips or nylon membranes onto which the sequences from thousands of different genes are immobilized, or attached, at fixed locations. The DNA may be spotted, or synthesized directly onto the support. DNA microarrays detect the change in gene expression levels, genomic gained and losses, mutations in DNA and infectious agents, diagnosis of genetic diseases, drug screening or forensic analysis. Developing the methods for detecting target hybridization, designing probe arrays, data analysis and reconstructing the target sequence are required for successful implementation of DNA chip technology. Such array technology thus forms the basis of integration of molecular biology, surface and analytical chemistry, advanced micro fabrication, robotics, software and automation. In this technique, RNA extracted from two samples are labeled with two different fluorochromes (generally the green cyanine 3 and the red cyanine 5 (Cy3, Cy5)) before being hybridized to a biochip consisting of large numbers of cDNAs/oligonucleotides arranged orderly onto a glass microscopic slide. After hybridization, a scanner records excitation of the two fluorochromes at given wavelengths and the intensity of the fluorescence emission signals that is proportional to transcript levels in the biological samples. The data is analyzed using specific software that enables clustering of genes with similar expression patterns, with the assumption that they share common biological functions [33, 44]. A new ultrasensitive electronic sensor has been developed by Singapore scientists that would speed up effectively DNA testing for disease diagnosis and biological research. The novel electronic sensor array would be faster, accurate and cost-efficient. Excellent sensitivity has been shown by the Nanogap Sensor Array in detecting the trace amounts of DNA. By saving time and cutting expenses, newly developed Nanogap Sensor Array offers a scalable and viable alternative for DNA testing. The presence of DNA is translated into an electrical signal by biosensor for computer analysis. The distinctively and meticulously designed sensor chip has the ability to detect DNA efficiently. The novel vertical nanostructure design and two different surfaces of the sensor allow ultrasensitive detection of DNA [45]. Lab-on-a-chip (LOC) Lab Chip is a device which involves preparation of sample and detection of DNA array. The objective of this technology is to integrate multiple processes, including collection of sample and pretreatment of it with the DNA extraction, hybridization and detection, on single self-contained microchip i.e. on a microfluidic platform. The capability to do all the processes on a single chip merits excellent advantages in terms of cost, speed, efficacy, effectiveness, contamination, sample consumption and automation. Laboratory transportation to the source of sample will be enabled by such miniaturization of analytical instrumentation. The development of these credit-card sized microlaboratories is commonly based on latest micromachining and microfabrication technologies, utilizing processes well known in the manufacture of electronic circuitry [14]. Cell-omic sensors Cell based detection systems can be combined with the microarray probes generating the hybrid arrays of cells within arrays of DNA/protein probs. This allows multiparameters analysis [46]. Applications of DNA Biosensors Biosensors plays a distinguished role in the field of environmental quality, food analysis, study of biomolecules and their interactions, drug development, crime detection, medical diagnosis, quality control, industrial process control, detection system for biological warfare agents, manufacturing of pharmaceuticals and replacement organs. The applications of DNA biosensor can be classified into three broad categories: sequencing, mutation detection and matching detection [47]. Their main use is for diseases diagnosis. Numerous diseases can be diagnosed and variety of infectious agents can be detected using DNA biosensors. 1. Viral diseases By DNA microarrays Either viral detection were being carried by immunological techniques (i.e. use of enzyme-linked immunosorbent assays (ELISAs) for the detection of circulating virus-specific antibodies) or PCR based techniques (i.e. reverse transcriptase (RT) PCR is used to detect the presence of specific viral genes). Both these approaches possess some limitations. Immunological tests need specific antisera and the production of antisera is laborious and time-consuming task whereas PCR is prone to failure in its ability to identify multiple viruses simultaneously [48]. Therefore, recent advances in DNA and protein microarray methodology fulfill the need of a rapid and sensitive detection of viral infections (also identify multiple viruses in parallel). DNA microarrays for viral analysis can be divided into viral chips and host chips. Each not only detects and identifies but also monitor the viral populations. In 1999, the first viral DNA microarray for the temporal profiling of viral (human cytomegalovirus, HCMV) gene expression was described. Viral replication or de novo protein synthesis was blocked by treatment of infected cells with cycloheximide or ganciclovir and then the expression profiles of viral genes was generated using microarray. Using this approach, the HCMV genes were classified to immediate-early, early or late expression classes, on the basis of their expression profile in response to the drug treatments. This can be used as an identifying hybridization signature for the molecular staging of an infection [49]. Orthopoxvirus causes smallpox and has two subtypes variola major and variola minor, of differing pathogenicity. This problem of orthopoxvirus subtype discrimination was solved by producing an array capable of correctly identifying the four of the orthopoxvirus species by laassri etal. [50]. HIV genotyping was done using chip technology [51]. A unique signature that is derived from viral is provided by viral chips. Host chip is used for examining the host response i.e. changes in host gene expression. This provides a molecular signature of infection. Cummings and Relman exposed an idea of host chips [52]. Vant wout etal. examined HIV 1 infection in CD4+ T-cells to detect changes in host gene expression that were specific to HIV infection [53]. Proinflammatory genes and genes involved in endoplasmic reticulum stress pathways, cell cycle, and apoptosis were the host gene signatures identified. Detection of hepatitis B virus Hepatitis B virus (HBV) is one of the causative agents of viral hepatitis which is leading cause of liver cancer. Infection of HBV is a public health menace for worldwide resulting acute and chronic clinical consequences. Acute HBV infection may lead to liver failure or may progress to chronic liver disease. Some chronically infected individuals may subsequently suffer cirrhosis and liver failure or develop hepatocellular carcinoma. Effective antiviral therapy may inhibit or retard the progression to severe liver disease. By DNA optical biosensor Bacterial alkaline phosphatase (phoA) gene and hepatitis B virus (HBV) DNA were used as target DNA. For capturing the target gene onto streptavidin coated magnetic beads, a biotinylated DNA probe was used. A calf intestine alkaline phosphatase labeled DNA probe was used for subsequent enzymatic chemiluminescences detection. The detection cycle was less than 30 min, excluding the DNA hybridization time that was about 100 min. at fematomole or picogramme levels both phoA gene and HBV DNA could be detected. No response signal was obtained when in sample target DNA did not exist [54]. By Piezoelectric DNA biosensor HBV nucleic acid probe was immobilized onto the coated gold surface of quartz crystal using polyethyleneimine adhesion, glutaraldehyde cross-linking (PEI-Glu) method or the physical adsorption method. Better results were obtained with the coated crystal with the PEI Glu method to immobilized HBV nucleic acid probe than physical adsorption method with respect to sensitivity, reproducibility and stability. With the hybridization reaction, the mass is increasing that resulted change in oscillating frequency. The frequency shifts of hybridization have better linear relationship with the amount of HBV DNA, when the amount was in range of 0.02-0.14 microgram/ml [55]. By electrochemical DNA biosensor An electrochemical DNA biosensor that is a glassy carbon electrode (GCE) modified with label free21mer single-stranded (ss) oligonucleotides (related to hepatitis B virus sequence) via covalent immobilization. [Cu(dmp)(H2O)Cl2] (dmp = 2,9-dimethyl-1,10-phenanthroline) is used as an electrochemical indicator. The method is simple, economical and allows the accumulation of copper complex within the DNA layer. Cyclic voltammetry and differential pulse voltammetry were used for electrochemical detection. The detection of hybridization is accomplished by using [Cu(dmp)(H2O)Cl2], where electroactivity and strong association with the immobilized dsDNA segment lead to significantly enhanced voltammetric signal. The differential pulse voltammograms for the cathodic signals of [Cu(dmp)(H2O)Cl2] at a bare GCE, and at ss- and dsDNA-modified GCEs are also recorded. The peak currents of [Cu(dmp)(H2O)Cl2] increased in the order of bare GCE, ssDNA/GCE, and dsDNA/GCE. After hybridization process, a greater peak current was observed from dsDNA/GCE than at ssDNA/GCE, because that more [Cu(dmp)(H2O)Cl2] molecules are concentrated or bound to dsDNA helix than to ssDNA. Thus, [Cu(dmp)(H2O)Cl2] can be used as an electroactive indicator for recognition of the surface hybridization process. The sensitivity of the electrochemical hybridization assay was investigated by varying the target oligonucleotides concentration. The different current value obtained in the DPV response of [Cu(dmp)(H2O)Cl2] after hybridization of probe with target is recorded with three repetitive measurements. The current response at about 0.485V increased in proportion to the amount of the target sequence used [56]. Detection of hepatitis C 3a virus An electrochemical DNA biosensor i.e. a gold electrode modified with a monolayer of a peptide nucleic acid probe and 6-mercapto-1-hexanol was used that depends on covalent binding of the14-mer PNA probe (related to the HCV genotype 3a (pHCV3a) core/E1 region) onto the electrode. This self-assembled PNA could selectively hybridize with a complementary sequence in solution to give dsPNA-DNA on the surface, and this increases the peak current of methylene blue (MB) which is used for detecting target DNA sequence. Diagnostic performance of the biosensor is described and the detection limit was found to be 5.7  ÃƒÆ'-  10à ¢Ã‹â€ Ã¢â‚¬â„¢11  M with a relative standard deviation of 1.4% in phosphate buffer solution, pH 7.0. This sensor exhibits high reproducibility and could be used to detect the target DNA for seven times after the regeneration process [57]. Cystic fibrosis Mikkelsens team, pioneered the utilization of redox indicators, demonstrated utility of electrochemical DNA biosensor for detecting the cystic fibrosis F508 deletion sequence which is associated with 70% of cystic fibrosis patients. For the 4000-base DNA fragment, 1.8 fmol was the detection limit in relation to a Co(bpy)33+ indicator. High selectivity for the disease sequence (not for normal DNA) was accomplished by doing the hybridization at high (43 °C) temperature [14]. 3. Diabetes Diabetes is a worldwide public health problem. The diagnosis and management of diabetes requires a tight monitoring of blood glucose levels. Thus millions of diabetics test their blood glucose levels daily by making glucose the most commonly tested analyte. The challenge is to provide such reliable and tight glycemic control. Electrochemical biosensors for glucose thus play a leading role. Amperometric enzyme electrodes, based on glucose oxidase (GOx) bound to electrode transducers, have thus been found the subject of substantial research [58]. Glucose sensors are commonly used to measure the blood glucose level of diabetes patients. Using the latest DNA chip technology, many scientists at Diabetes Center have discovered the implication of new gene in the cause of type 2 diabetes. They created an abnormality in one of these genes known as ARNT (aryl hydrocarbon receptor nuclear translocator gene which is a member of a family of transcription factors) in mice and the mice developed changes in insulin secretion which were same as in patients with type 2 diabetes. The ARNT is required for the development of normal embryo. It is also related to responses to hypoxic stress condition and certain environmental toxins, such as dioxin and thus for integrating genetic and environmental insults it is present at specific potential sites. The expression of many other genes in the cell is regulated by transcription factors like ARNT and thus they are the master regulators of cellular functions. The first use of DNA chips has been represented by this study,

Chaucers Canterbury Tales - The Character of the Reeve Essay -- Reeve

The Character of  the Reeve in Canterbury Tales    In The Canterbury Tales, Chaucer’s descriptive technique used to present the Reeve emphasized his physical characteristics as well as the success he attained in his occupation.   It is evident that Chaucer gives two different perceptions of the Reeve, one perception is of his physical makeup and the other is of his success achieved in his occupation.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   In Chaucer’s introduction of the Reeve, he immediately begins with the Reeve’s physical makeup, as shown in this excerpt from The Canterbury Tales:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   â€Å"His beerd was shave as neigh as evere he can;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   His heer was by his eres ful round yshorn;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   His top was dokked lik a preest biforn;   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Ful longe were his legges and ful lene,   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Ylik a staf, ther was no calf yseene (590-594).†   This excerpt shows the attention to detail Chaucer selected to introduce the Reeve.   Chaucer also gives the Reeve a name, which is not commonly done for most pilgrims in The Canterbur... ...w because he does not own the land that he presides over.   Even though he is successful and has gained some wealth through his occupation, he still does not own the property and possessions and therefore cannot attain the higher social status.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   In conclusion, Chaucer presents the Reeve in detail uncommon to most of the pilgrims in The Canterbury Tales.   This detail along with the fact that the Reeve was given a name suggests that the Reeve tends to be more of a   specific individual than a general presentation of a class or type of person.   He also was prosperous in his occupation of superintendent of his master’s estate, and even though he was respected and acknowledged for his accomplishments and wealth, he did not have the high social status because of his lack of land ownership.

To Kill A Mocking Bird Essay -- To Kill a Mockingbird Essays

2. â€Å"What is the significance of the title of the novel† â€Å"I’d rather you shoot at tin cans in the backyard, but I know you’ll go after the birds. Shoot all the bluejays you want, if you can hit ‘em, but remember it’s a sin to kill a mocking bird.† Atticus Finch recites these lines to his two children, Jem and Scout after he gives them air-rifles for Christmas. Scout is curious, as this is the first time that she has ever heard her father refer to anything as a sin, Scout asks Miss Maude what Atticus meant by this. Miss Maude tells Scout that mocking birds don’t rip up people’s garden’s or annoy them in any way, all they do is play beautiful music for us to listen to. To Kill A Mocking Bird is set in a small town in South America called Maycomb. Most of the town’s people of this happy town are not at all what they seem for there is a great hate for all coloured humans. At first glance many readers would wonder how the title evolved, but once you explore the text you begin to understand what the bases of Harper Lee’s message. Harper Lee has portrayed two characters as Mocking Birds. The first of these is Tom Robinson. Tom Robinson is a Negro living in Maycomb who becomes notorious when he is wrongly accused of the rape of a white woman. Atticus knows that the battle will not be an easy case to win, but decides to represent Tom Robinson, as he says that he couldn’t hold his head up in town or tell the children what to do. Tom Robinson was a harmless member of society who nev...

Comparing Feminist Poetry by Plath and Sexton Essay -- Feminism Femini

Comparing Feminist Poetry by Plath and Sexton Poetry "should be a shock to the senses. It should also hurt" Anne Sexton believed (Baym 2703), and evidence of this maxim's implications echoes loudly through the writing of Sexton as well as through the work of her friend and contemporary Sylvia Plath. Plath and Sexton's lifetimes spanned a period of remarkable change in the social role of women in America, and both are obviously feminist poets caught somewhere between the submissive pasts of their mothers and the liberated futures awaiting their daughters. With few established female poets to emulate, Plath and Sexton broke new ground with their intensely personal, confessional poetry. Their anger and frustration with female subjugation, as well as their agonizing personal struggles and triumphs appear undisguised in their works, but the fact that both Sexton and Plath committed suicide inevitably colors what the reader gleans from their poems. However, although their poems, such as Plath's "Daddy" and Sexton's "Little Girl, My String Bean, My Lovely Woman," deal with the authors' private experiences, they retain elements of universality; their language cuts through a layer of individual perspective to reach a current of raw emotion common to all human, but especially female, understanding. In Plath's "Daddy," written just before her death and published posthumously, the most readily accessible emotion is anger, and much of the poem is couched in autobiographical allusions. Plath's own father died of a gangrenous infection, caused by diabetes he refused to treat, when Plath was eight years old, and his death was "the crucial event of her childhood" (Baym 2743). Plath makes personal references to her father as a... ...life struggles and human relationships- of the things women carry with them that make them who they are. Works Cited Baym, Nina. General Editor. "Anne Sexton." The Norton Anthology of American Literature. 5th ed. New York: W.W. Norton, 1998. 2703-4. ---"Sylvia Plath." The Norton Anthology of American Literature. 5th ed. New York: W.W. Norton, 1998. 2742-44. "Electra Complex." The World Book Medical Encyclopedia. Rush-Presbyterian-St. Luke's Medical Center, Chicago. April 2002. < http://www.rush.edu/index.html>. Plath, Sylvia. "Daddy." The Norton Anthology of American Literature. 5th ed. General Editor, Nina Baym. New York: W.W. Norton, 1998. 2748-50. Sexton, Anne. "Little Girl, My String Bean, My Lovely Woman." The Norton Anthology of American Literature. 5th ed. General Editor, Nina Baym. New York: W.W. Norton, 1998. 2707-09.

The theory of employee relations Essay

Employment relations Introduction            Conventionally, employees are deemed to strike for various reasons. From scholarly works, a strike is defined as suspension in production as the workers and their employers engage in the possible way of dividing the surplus that has been achieved within their relationship. (Metcalf and David, 1993) From modern perspective, strikes involves at least one of the arguing parties having some private information that they do not want the other party to get hold of about this suspected surplus. In empirical perception, strikes are generally considered to be rare. From the findings of economists; they have concluded that strike cases are usually rampant during the business cycle peak, and strikes duration is considered to be limited when the economy is strong. Strike activities are evidently influenced by legislative environment, particularly that legislation that restricts use of replacement of workers (Blyton and Turnbull, 2004).            An employee’s labor value is greater compared to the wage provided by the employer, that is after considering the relationship of employment. This in return provides an opportunity for rise of surplus that is to be divided among the employee and the employer. Thus, a strike is considered as the act of suspending production as the two sides gets into an argument on how to divide this surplus amicably. The guardian, â€Å"yes striking is a human right,† this command is given by the international treaties voluntarily accepted by British successive governments; this same treaties are being bound by the United Kingdom (The Guardian, 2011).            According to the guardian, British government has been directed by the international community on human rights to relax the already existing restrictions and cease treating lawful strikes as a breach rather than suspension of employment contract to the employees. If the British law intersect with the international obligations, then it would not be easy for the bully employers to unilaterally suspensions of the striking employees (The Guardian, 2011).            Mills and Quinn (1982) In an ideal competitive situation, employment surplus is not real: individual employers compete with other employers, who are concerned with biding salary and wages to the point when it matches employee laborer value, also the individual workers will too compete with other fellow workers who tend to bid their remunerations until they meet the one that has been scheduled by the respective employers. From this assumption an employee who tends to strike they are immediately replaced by other equivalent works who meet the demands of the potential employer (Brenner, Aaron, Benjamin and Ness, 2009).            The worker who is willing to take this bid takes the day. This situation also happens to the employers, also employers who try to reduce the worker’s salary and wage; they will receive a set back as the potential workers will move to the employer who is ready and willing to provide that remuneration that the worker is willing to work for. Through this, the workers are thus able to replace their former employers with other favorable employers giving out competitive prices (Zeidler and Frank, 1968).            Lambert and Bartlett (2005) Evidently, it is true that strikes will happen if and only if there is an extra income from production that both the employer and the worker see that it is worth fighting for, hence strike will never occur in a noncompetitive market of labor. Despite the strikes being human rights, they also need to be viewed with a credible mind. Through a sound mind one is able to make a viable decision that will solve the whole mess amicably. This will need personnel who will explain the likelihood of a strike occurring and then recommending means of settlement, thus there could not be any wastes brought about by strikes (Hicks paradox of 1932). Critically building on Hicks paradox, we are enabled to suggest that the two parties are fighting for some crucial information that each want to keep especially the employer. Apparently the associated wastage realized through strikes is considered a cost of trying to obtain this information especially on the p art of the employee as they initially lack this important information that they know will relieve them the bondage of underpayment (Rosenbloom and Joshua, 1996).            To have a clear understanding of these analogies it is important to get a glimpse of what the workers strike theories hold for better explanation. There are various theories that will help to give a reason as to why really workers in the essential services need to go on strike for their grievance to be hard, by either group understanding or through their respective Unions. Unions go on strike when they are sure that the employer is to meet their demands without undergoing any financial crisis. These theories are crucial as they are the ones that give these unions a bargaining ground as illustrated below (Barrett and Boyd, 1914). Institutionalization theory            This particular theory is attributed two gentlemen Hartman and Ross according to Bean perspective (Bean, 1994) the theory asserts institutional mechanisms of negotiating, such as common bargaining protocols helps to reduce the supposed conflicts that are bound to occur due to the strike. Olafsson (1982), perspective about the theory, suggest that for highly developed industrial systems relations are commonly associated with reduced conflict levels.            Some countries that believe in this theory have been associated with reduced strike conflict level these countries include: Norway, Sweden, and Denmark are some of the singled out as the unique examples the countries that have developed industrial peace model, associated by centralized movement of labor, they also have comprehensive means of negotiations, and lastly they have the legal regulations that are effective in controlling strike activities and disputes procedures.            Hale (2008) from the study of conducted by Harmatan and Ross determined the factors that influenced strike activities in countries of study. The study found that the countries that have stable labor unified movements that are recognized and willingly accepted and with intensively developed common bargaining protocols are the ones that experience industrial peace. Hartman and Ross concluded centralized bargaining systems minimize levels of industrial conflicts in the field of essential services delivery. This is due to the claim of the two that employers and workers organization are at a point to put real behavioral limits within their respective members. Implicit or Relational contract theory            Implicit or relational theory, asserts that there exist a contract between worker’s and employer Unions, the theory is based in an infinitely recurring practice with imperfect monitoring. Kelly (2002) has it that, conflict is unavoidable results of informational asymmetries. The various resolutions of conflicts, strikes slow down, dismissal, low morel, and resignations are not essentials by themselves ingredients of this theory. For instance the strikes will seem to have a zero impact generally under particular configurations, as the conflict is present, but assumes another form.            Blyton and Turnbull (2004) indicates that the high efforts and the high pay initiatives agreements between unions and the respective employer is possible to be supported â€Å"Public Perfect Nash† equilibrium of a recurring event. If these particular players are deemed to be patient enough, just at the cost with random reversions for inefficient series of actions, through which strikes and inflexible wages, or outsourcing and slowdown is bound to take place. This theory suggest that at equilibrium, the respective unions goes on strike simply when the provided wage has been considered to be too low and the exact state nature reality, considered information by the employer to be private and has never been revealed to the workers’ union. Hence, this behavior is turned to be rational in a recurring interaction framework; this eventually causes necessary cooperation in the good times. Principal Agency theory            Johnson and Ashenfelter model suggests that strikes happens only when the salary expectations of the file and the rank do not meet at a common ground with what the prospective employer is ready to pay their staff. In case the union directors present a low salary contract for reviewing. In the situations when the file and the rank’s wage expectation are high, then the rank and the file are regarded with an attempt to selling out to that responsible management. When the above mention statement happens, instead of risk dissension the workers union leaders would prefer to strike internally (Blyton and Paul, 2004).            The major aim of an internal strike is to convince the employees belonging to the union that the wage they are expecting is not possible. According to Hale (2008) â€Å"the basic function of a strike is to square up the membership’s wage expectations with what the firm is willing and ready to pay the workers† the implication the theory is that the union’s salary demand should come down during a strike time. From another perspective this theory receives some critics on the ground that the wage needs are merely based on factor of conjecture, instead of being derived from the bargaining process (Metcalf and David, 1993). The theory of private information            As it has been outlined from the above discussion, the employer usually holds some crucial information that normally interests the worker about their working conditions, especially the payment part. This theory thus states that strikes are illustrated well by this private information in regard to the critical aspect important in reaching an agreement, for instance the firm’s willingness for payment (Metcalf and David, 1993).            Why do the workers have to strike? According to the theory of private information, workers only go on strike because this is the only credible means through which they are able to communicate the so called private information. The theory also claims that a company with great willingness to compensate their workers does it with high salary without the employees going to a strike. However, this is also true that the company with low interest of settling the worker, they end up paying the workers low wages because they are ready receive the strike and its impacts. The theory is crucial in the application in strikes when is considered to be bilateral monopoly setting, through this the employees’ union and the firm bargain with information that is asymmetrical, or when the informational conflict is between leaders union, file, and the rank. Form this theoretical information is worth noting that private information is never verified at low cost among other theorie s.            Employees do not strike only for economic reasons; they can also strike in demand of working conditions improvement, or with aim of mutual aid, and protection of the workers in another union. This statement elaborate a factor called job satisfaction within the employees which can be defined as that emotional condition that come as a result of appraisal of an employee’s job. The statement suggest workers develops negative of positive attitudes towards their work or specific sections of the job mainly through, an internal state of mind of respective individuals, generally it is that consideration of our belief, behaviors, and our feelings. When job satisfaction is positive, this can result from favorable working terms workers are considered to be active. Workers activeness is determined from the output of production, motivated workers produces quality services because they are able to utilize fully their potentials. Unmotivated workers results in under product ion as they are not willing to utilize their potentials for the benefit of the employer. The outcomes of strikes in the essential services sector            Despite of strike being a human right through which they can air their grievance, strikes are associated with adverse effects that come aftermath the strike has taken place. The results can either be positive, that is the demands of the workers are met and sometimes the results will be negative not favoring the claims of the striking workers. So the striking workers are always prepared for any of these twoutcomes in their efforts to manages and influence the consideration of their needs being addressed with human touch from their employers through the union or at times through the individual employees alone.            Considering the 1919 the General Winning strike according to the Canadianonline.com, it resulted to adverse effects. Among them, the metal workers were compelled to go back to work without a dime increase in their pay that they were demanding, this sounds like they just wasted their time. The employees had to be sent to jail, the foreign workers were deported, and hundreds of others had to be demoted. Seven ring leaders of the strike received a two years conviction for conspiracy of trying to overthrow the government. Apart from these negative results still something good came out of it. Eleven of the labor candidates who won the seats out of these four of them were the strike leaders.            The General Winning Strike made strike in Canada to receive a collective ground for bargaining after almost 20 years. This suggests that within these 20 years the working condition in Canada was compared to hell since both the unions and the workers had no power to bargain for their wage increase even when there was a surplus with the scope of production. Though this the economy of Winnipeg greatly went down for a long time. This also resulted in a social stratification that is the north was classified as the working class and the south as the Troy state            Another area of essential service sector let us consider the teaching sector. Brison, David and Smith (2006) form the reports that evaluated the impacts of the Ontario teachers’ strike of 1975 to early 1976. Studies were in the respective schools lagged behind because they started just after the end of the strike and also there was lack of cooperation from the teachers. Though the study conducted found no effect that was no effect on the change of student grades. The other study in the same subject also came out with different suggestions, concerning student’s attitudes towards their teachers. Surprisingly the strike did not affect the attitude towards their respective teachers.            From the third study that was concerned with the school attendance resulted into a null hypothesis. The rate of learner’s dropout was evident from the results that were obtained especially from grade 9 to grade 13. The study concluded that a strike has an impact on student dropout and also on movement to postsecondary education. Ahmed and Syed (1989) Cumulative the strikes are regarded to have negative outcomes on the academic performance of the students especially in the senior grades, particularly in learning such subjects like science and mathematics where learning involves summation of knowledge. Even though the strikes did not have any focus on teachers’ effects from external sources it is realized that after the strike event the teachers became less idealistic in regarding teaching profession as a calling but rather a job just like any other (Matheson and Victor,2006). Recommendations and conclusion            From the above reviews, there is a revelation that there is a strong relationship between strikes actions and job satisfaction. In the countries that have high job satisfaction, strike incidences are limited or never exist and the reverse is true for other countries. The studies show that low industrial conflict levels are associated with greatly developed industrial relation systems. Among the recognized countries experiencing the benefit of industrial peace are Finland, Sweden, and Norway since that have unified and stable labor movements, in addition to these they also have a collective platform of bargaining that are accepted by the employers.            This hence recommends that each country must try to have greatly developed systems in the industrial relations, also should have a well designed collective bargaining policies which has to be recognized and then accepted by the works across the labor sector and also the government and the employers must accept these terms. There is a need then for the country to have constant to review conditions of the worker to match the current economic situation with this review the workers and the employers will not engage in a fight for the surplus production.            The authorities also have a moral responsibility of ensuring that there are annual forums that joins the employer and the workers with their respective ministries to discuss the current issues affecting the various parties with the hope of addressing this issues at the preliminary before cropping up to create unwanted strikes. Timely strikes aversions are crucial, since it helps to reduce the possible social, political, and economic results of the strike. This calls upon the government responsible ministries to be aware of the challenges that the workers can face.            Unions should act strongly to fight the policy of temporal workers replacement. Replacing workers reduce the strength of having a common bargaining for their demands. Once the employer has replaced the striking employee, production process goes on as usual hence thinking about the servicing worker who is on strike will be a thing that has been put aside for a while. References Blyton, Paull, and Peter Turnbull. The dynamics of employee relations. 3rd ed. Houndmills, Basingstoke,Hampshire: Palgrave Macmillan, 2004. Print. Blyton, Paul. The theory of employee relations. na: na, 2004. Print. Brenner, Aaron, Benjamin Day, and Immanuel Ness. The encyclopedia of strikes in American history. Armonk, N.Y.: M.E. Sharpe, 2009. Print. â€Å"Guardians veto bank bill–but not over president.(Economy: Money and its impact).† Iran Times International 7 Jan. 2011, ed, sec. Print. Hale, Dominic. â€Å"International comparisons of labour disputes in 2006.† Economic & Labour Market Review 2.4 (2008): 32-39. Print. Kelly, John E.. Rethinking industrial relations mobilization, collectivism and long waves. Taylor & Francis e-Library ed. London: Routledge, 2002. Print. Metcalf, David, and Jonathan Wadsworth. Do strikes pay? 1992. Print. Metcalf, David H.. New perspectives on industrial disputes. London: Routledge, 1993. Print. Mills, Daniel Quinn. Labor-management relations. 2nd ed. New York: McGraw-Hill, 1982. Print. Zeidler, Frank P.. Rethinking the philosophy of employee relations in the public service. Chicago: Public Personnel Association, 1968. Print. Ahmed, Syed M.. â€Å"The effects of the joint cost of strikes on strikes in Canadian manufacturing industries à ¢Ã¢â€š ¬Ã¢â‚¬Å" a test of the Rederà ¢Ã¢â€š ¬Ã¢â‚¬Å";Neumannà ¢Ã¢â€š ¬Ã¢â‚¬Å";Kennan theory.† Applied Economics 21.10 (1989): 1353-1367. Print. Barrett, E. Boyd. Effects of strikes. Dublin: Office of the â€Å"Irish Messenger†, 1914. Print. Brison, David W., and Anthony H. Smith. The effects of Ontario teachers’ strikes on students: summary and integration of three component studies. Toronto: Ontario Ministry of Education, 1978. Print. Matheson, Victor A.. â€Å"The Effects Of Labour Strikes On Consumer Demand In Professional Sports: Revisited.† Applied Economics 38.10 (2006): 1173-1179. Print. â€Å"Winnipeg General Strike 1919.† About.com Canada Online. Web. 7 Mar. 2014. . Collections of the United Farm Workers of America. Woodbridge, CT: Primary Source Media, 2009. Print. Hain, Peter. Political strikes: the state and trade unionism in Britain. Harmondsworth, Middlesex, England: Viking, 1986. Print. Lambert, Josiah Bartlett. â€Å"If the workers took a notion†: the right to strike and American political development. Ithaca, N.Y.: ILR Press, 2005. Print. Report of proceedings at the fourth ordinary Congress of the International Federation of Trade Unions: Held at the â€Å"Grand Palais†, Paris, from August 1st to 6th 1927 ; together with reports of the Conferences of the International Trade Secretariats, and t. Amsterdam: International Federation of Trade Unions, 1927. Print. Rosenbloom, Joshua L.. Strikebreaking and the Labor Market in the United States, 1881-1874. Cambridge, Mass.: National Bureau of Economic Research, 1996. Print. Source document

Measuring Reliability

The Myers-Briggs Type Indicator (MBTI) is one of the most popular personality tests in the world today.   However, data reviewed from more than twenty MBTI research studies has indicated that the test has inadequate validity.   In other words, MBTI does not adequately measure what it is meant to measure.   Moreover, MBTI has reported reliability coefficients for its four scales on general population samples in the ranges from 0.61 to 0.87.   Experts on psychometric testing reveal that reliability coefficients for short personality tests should actually be in the range of 0.7 to 0.8 (Psychometric Success). Does this mean that MBTI is unreliable? – No.   While this important personality test sometimes reveals a lower reliability coefficient than the other personality tests, even when its reliability coefficient is close to 0.61, the test is said to give us a dependable measure of the constructs it measures at least 61% of the time.   To put it another way, at least 61% of the people who use the MBTI once would see that their scores on the different constructs of the test would not change on a second testing session and all subsequent testing sessions. Reliability is also known as â€Å"repeatability† or â€Å"consistency.†Ã‚   A test with perfect reliability has a coefficient of 1.0.   A test with no reliability whatsoever has a coefficient of 0.   A test with perfect reliability is one which gives us absolutely consistent results with the same sample.   The higher the reliability, the better is a test, scientifically, given that we can trust the results of this test with confidence, knowing that they will not change drastically through retesting (Trochim, 2006). With MBTI, we can be confident that the test would show us a true picture of an individual’s personality at least 61% of the time.   Although this value is better than 50%, MBTI would have  given us greater confidence in terms of its measurement if its reliability coefficient always fell in the range of 0.8 to 0.9.   This would have led us to believe that MBTI is most definitely a trustworthy measure of an individual’s personality type. References 1.Psychometric Success. â€Å"Myers-Briggs Widely Used But Still Controversial.† Available at http://www.psychometric-success.com/index.htm. (31 January 2007).    2. Trochim, William. (2006). â€Å"Theory of Reliability.† Research Methods Knowledge Base. Available at http://www.socialresearchmethods.net/kb/reliablt.php. (31 January 2007).         

Crips and Bloods

The movie Crips and Bloods: Made in America is about a cluster of neighborhoods in the heart of Southern California. It highlights young African American men in two separate gangs called the Crips and the Bloods. The Crips are one of the oldest and largest gangs in the United States and the Bloods are a street gang originating from Los Angeles, California. They have been involved in murders, robberies, and drug dealing in the Los Angeles area. The film interviews former gang members Ron, Bird, and Kumasi, while recount their experiences growing up in the neighborhood in the 1950s and discussing the dangers of their previous decisions. Throughout this movie, the director accurately demonstrated many social theories however the labeling theory and the differential association theory stand out in the film. Labeling theory â€Å"examines the ascribing of a deviant behavior to another person by members of society† (OpenStax College, 2013, n.p.). This theory applies to deviance situations, which is a violation that is a rule made up by society. For example, â€Å"a teenager who lives in an urban area frequented by gangs might be labeled as a gang member. Accordingly, the teenager might begin to behave like a gang member or become one† (Chegg, 2018). This labeling theory perhaps explains better why young black Americans fall into crime and criminal gangs and this theory is exemplified a number of different times during the movie. In the movie, young men were stopped by the police for no apparent reason. Black people were not even supposed to enter a white neighborhood. And if they saw a young white twelve-year-old boy they were expected to say â€Å"yes or no sir.† The black men did not feel as wanted or respected and caused them to do more criminal acts. ). Individuals that are arrested, punished or prosecuted are labeled as criminals and others view and treat the labeled individuals as criminals. And also the labeled people find it difficult to obtain any form of formal employment. This situation led them into drug abuse and trafficking for the sake of raising money for their daily needs. Differential association theory is â€Å"a theory that states individuals learn deviant behavior from those close to them who provide models of and opportunities for deviance† (OpenStax College, 2013, n.p.). Simply Edwin Sutherland's this theory proposes that people learn attitudes, techniques, morals, and motives for criminal behavior through their interactions with others. For example, â€Å"a child who grows up among professional thieves is more likely to learn to steal; such a person might learn not only to regard stealing as acceptable but also specific techniques for stealing. In this view, younger people are more likely to learn deviance than older people† (Chegg, 2018). Throughout this whole movie, most of the former gang members are describing their reasons for joining a gang. For example, any of the African American children were not allowed to be admitted to any type of youth organizations. Even though a mother of a former gang member tried to sign her son up for Boy scouts, he was also rejected. If they had let that boy sign up for the youth program that would have taken him out of gang-related activities and lives would have turned upside down.