Methods of DNA Identification

Methods of DNA Identification To isolate DNA from blood, saliva, buccal swab and betel quid by phenol-chloroform method and chelex method and compare the efficacy of both the methods. To carry out restriction digestion of the DNA samples isolated from above mentioned sources using the restriction enzyme EcoRI (G|AATTC) and identify individuals based on the pattern of restriction banding and to ascertain the applicability of the restriction digestion in forensics MATERIALS AND METHODS: Blood, saliva, betel quid and buccal swab were collected from 15 patients and DNA isolation was done by phenol-chloroform method and chelexmethod. DNA fingerprinting was carried out using EcoRI restriction enzyme. RESULTS:  DNA could be extracted from residues of saliva, DNA fingerprinting done with the isolated DNA was able to match with those of individuals. Chelex method was found to be more efficient than the Phenol-chloroform method KEY WORDS: Betel Quid, Chelex method, DNA,DNA fingerprinting,Phenol chloroform method Introduction DNA fingerprinting  has ascertained an increasingly imperative role towards decision making in judiciary. DNA tests have helped convict suspects, to exonerate suspects or overturned previous convictions. Scientific evidences such as fingerprints, blood, semen, shreds of clothing, hair, weapons, tire tracks, and other physical evidence at the crime scene can be a more riveting to a tribunal than the testimony of an eyewitness. DNA is more suitable because DNA remains scathe lessin challenging environments where such evidence is found. The DNA molecule holds an impressive dependability to withstand time. 1 DNA profiling compares the DNA fragment lengths and patterns. The isolated DNA from the samples is fragmented using a restriction enzyme. Then the length of the resulting fragments is determined by electrophoresis and comparedby a visual interpretation of the pattern of DNA bands. 2 DNA can be sourced from freshblood, fresh or dried human buccalswabs, soft tissue, saliva and salivary stains. Optimizing the methodology in DNA extraction from various sources have been tried by many studies. Minute quantities of saliva allows establishing DNAprofile. 3DNA has been proven to be isolated from cell samples from objects that was in contact with the body and from sources like chewing gums, cigarettes, bite marks in foods, among others. Restriction fragment length polymorphism (RFLP) analysis provides details of the DNA which is referred as a DNA fingerprint. As DNA is unique to every individual, analyzing the sequence helps in identification of specific patterns of each individual. DNA profile is considered as valid evidence in the court of law for paternity disputes and human identification. Standardization of DNA extraction technique will improve the reliability and speed up sample processing time. 4-6 Limited availability of biological samples in a crime scenechallenges the procedure of extraction , characterization and analysis of DNA. Furthermore, difficulty arises in retrieving DNA from stains and degraded samples which provide contaminated or poor qualityDNA. Hence, purification of DNA from samples is still a significant step in obtaining useful genotypes. Notwithstanding, tremendous advances have been made in the recent times in DNA testing. 7 Chewed betel quid (BQ) stains are encountered frequently on crime scenes in Southeast Asian countries. Though the quid presents as an important biological evidence, the forensic analysis using betel quid as an evidence has been impeded due to difficulty in extraction of human DNA . Hence, constituting a definite method for extracting DNA from chewed Betel quid residues is of paramount importance. 8 Saliva found on victims of several violent crimes is a potential source of DNA. They can be recovered from bite marks, cigarette butts, betel quid, postage stamps, envelopes and other objects. However , salivary stains usually dry up easily becoming invisible, making recognition and collection difficult. Among the various biological sources available, salivary analysis have great discriminatory power and can be incorporated into a criminal investigation . Improvisation of DNA extraction procedures will improve its reliability and also help to expedite the process. The present study aims to isolate DNA from blood, saliva (under different conditions) by phenol chloroform method and chelex method and to find the efficacy of these methods in extraction of DNA from traces of saliva. 9,10 ISOLATION OF DNAFROM BLOOD AND SALIVA BY PHENOL CHLOROFORM METHOD : The DNA was extracted with an equal volume of phenol: chloroform: isoamyl alcohol. This mixture was centrifuged at 10000rpm for 5 minutes. The aqueous phase was collected and extracted with chloroform: isoamyl alcohol mixture and centrifuged at 10000rpm for 5 minutes. The supernatant was transferred to a new microfuge tube and 0. 6 volume of isopropanol was added. The spongy white precipitate was transferred to a microfuge tube and added equal volume of ethanol was added. Then it was centrifuged at 10000rpm at room temperature for 10 minutes. The supernatant was drained and to the pellet 100 µL of TE buffer was added stored at 4 °C. ISOLATION OF DNAFROM BLOOD AND SALIVA BY CHELEX METHOD: 0. 5 ml of whole blood was collected in 2 ml tube and the cells are harvested by centrifugation at 3000 rpm for 3 min. at 4 °C. The supernatant was discarded. 0. 8 ml TBP buffer was added to the collection tube, vortexed gently, then centrifuged at 3000 rpm for 3 minutes, supernatant was discarded. The next stepwas continued if the blood pellet looks mauve 0. 5 ml of TBM buffer was added to the tube, and vortexed followed by addition of 3  µLof proteinase K and incubated at 55 °C for 30 minutes. The sample was centrifuged for 2 minutes at 5000 rpm and the supernatant saved to 2 ml tube and then added 260  µL of absolute ethanol. The mixture was applied to EZ-10 column, centrifuged at 8000 rpm for 1 minute; discarded the flow in the collection tube. 500  µL of wash solution was added and centrifuged at 8000 rpm for 1 minute. This step was repeated spin at 8000 rpm for an additional minute to remove residual amount of wash solution. The column was placed into a clean 1. 5 ml microfuge tube and 30  µL of elution buffer was added into the center part of membrane . The tube was incubated at 50 °C for 2 minutes centrifuged at 10,000 rpm for 1 minute to elute the DNA from the column The standards and samples were removed from the freezer and thawed. In a separate sterile 1. 5 ml microfuge tube for each standard/sample, 10  µl of DNA was mixed with 990  µl of D. I. water and vortexed . The solution was allowed to stand for 10 minutes to ensure the complete diffusion of DNA throughout the solution. This represents a 1:100 dilution of the standards and the DNA samples. B. DNAquantification The DNA sample was briefly vortexed and the solution wastransfered to the cuvette of the spectrophotometer with care not to create bubbles. The cuvette is inserted into the spec ensuring the correct face of the cuvette is in line the light beam. . An absorbance reading appears on the screen . Reading is continued until all standards and samples have been quantified. The concentration of DNA in the sample is determined according to the conversion factor (A260 of 1. 0 = 50  µg ml-1 DNA). The concentration of DNA in the sample can be read as  µg/mL using the conversion factor and dilution factor . RESTRICTION DIGESTION: Restriction enzyme buffer was vortexed before pipetting to ensure that it was well-mixed and was added to the tube . Appropriate amount of DNA to be cut wasvortexed before pipetting to ensure that it was well-mixed and was added to the tube. After vortexingthe enzyme to ensure that it was well-mixed 1 ÃŽ ¼L of enzyme EcoRIwas added. The mixture is placed in thermal cycler (Eppendorf) for2-3 hour incubation at 37 °C . To heat inactivate the enzyme the mixture is maintained at 80 °C for 20 min. The mixture is kept at 4 °C until the reaction mixture is out of the thermal cycler. Agarose Gel Electrophoresis Protocol Preparation of the agarose gel 1. 25 g Agarose powder was taken in 500 ml flask and 125 ml of TAE Buffer was added to it. The mixture is melted in hot water bath till a clear solution forms. The solution is allowed to cool to a temperature of 50-55 °C by periodic swirling to achieve even cooling. To it ethidium bromide solution was added. The ends of the casting tray are sealed with two layers of tape. The combs are placed in the gel casting tray. The melted agarose solution was poured into the casting tray and allowed to cool until it is solid. The comb and the tape are removed carefully. The gel is placed in the electrophoresis chamber. 2-3 mm of TAEBuffer is added over the gel. Loading the gel 6 à ¯Ã‚ Ã‚ ­l of 6X Sample Loading Buffer is added to each DNA sample containing tubes. 20 à ¯Ã‚ Ã‚ ­l of each sample is pipetted into separate wells in the gel. 10 à ¯Ã‚ Ã‚ ­l of the DNA ladder standard is pippeted into one well of each row on the gel. Running the gel The lid is place on the gel box, the electrode wires are connected to the power supply. The power supply is turned on to about 100 volts. To ensure the correct direction of the current, the movement of the blue loading dye is checked. The power supply is continued till the blue dye approaches the end of the gel. The wires are disconnected from the power supply. The lid is removed from the electrophoresis chamber. Using gloves, gel is carefully removed and observed in a transilluminator for the DNA bands. RESULTS: Isolation of DNA was done from blood ,fresh saliva, saliva stored at -20 °C, saliva stored at 37 °C for 24hrs ,buccal swab and betel quid by both the phenol-chloroform method and the chelex method. . Gel electrophoresis of the isolated genomic DNA was carried out on 0. 8% agarose gel. (figure 1) After restriction digestion electrophoresis gel is prepared to run and to identify the number of bands. DNA samplesobtained from blood were labelled as Aband subsequently as Bb,Cb, DbEbas shown in table 2. DNA obtained from fresh saliva were labelled as As,Bs, Cs, Ds,Es. DNA obtained from saliva stored at -20 degree were labeled as AfsBfsCfsDfs. Efs. DNA obtained from saliva stored at room temperature were labelled as Ads,BdsCdsDdsEds DNA obtained from bloodof 5 individuals was made to run in the well marked 1 to 5 in a uniform manner ie DNA obtained from the first individual named as Ab, was made to run in well No. 1 . DNA obtained from second individual named as Bb was made to run in well No. 2 DNA obtained from third individual named as Cb was made to run in well No . 3. DNA obtained from fourth individual named as Db was made to run in as well No- 4. DNA obtained from Fifth individual namedEbwas made to run in well No. 5. (table 2) But while running DNA obtained from saliva of different sources the order was changed randomly. For example DNA isolated from fresh saliva for the first individual (As) instead of being run in the first well ie well No -6 was made to run in the third well( well no 8) and DNA isolated from saliva stored at -20 degree for the first individual(Afs) instead of being run in the first well ie well No-11was made to run in the third well (well No. 13)and DNA isolated from saliva stored at room temperature for the first individual(Ads) instead of being run in the first well ie well No-16 was made to run in the fifth well (well No. 20). Likewise DNA isolated from different sources of saliva of different individuals made to run in different wells and the number of bands produced is identified . From the figure 1 it could be identified that the well number 1,8 ,13,20 corresponding to DNA isolated from the first individual from various sources named Ab AsAfs Ads identified by the yellow arrow has uniformly three bands. For the well number 2,7,14,19 corresponding to DNA isolated from the second individual from various sources named BbBsBfsBds identified by the blue arrow has uniformly 6 bands . various DNA isolated from the fifth individual from various sources namedEbEsEfsEds identified by the green arrow has uniformly 4 bands . From the above figure itcould be identified that the well number 1,10 corresponding to DNA isolated from different source for the first individual named Ab,AbS,identified by the yellow arrow has uniformly four bands. For the well number 2 and 6 corresponding to DNA isolated from second individual from blood and buccal swab named BbBbSl identified by the blue arrow has uniformly 6 bands . For the well number 3 and 7corresponding to DNA isolated from third individual from blood and buccal swab namedCbCbS identified by the red arrow has uniformly 5 bands . For the well number 4and 8 corresponding to DNA isolated from fourth individual from blood and buccal swab named DbDbs,identified by the aqua arrow has uniformly 7 bands. For the well number 5and 9 corresponding to DNA isolated from fifth individual from blood and buccal swab named EbEbsE identified by the green arrow has uniformly 8 bands . This shows that DNA obtained from an individual from blood and buccal swab produce uniform banding pattern. This shows that DNA obtained from an individual from various source produce uniform banding pattern . Identification of individual from traces of saliva which could be used for forensic application -Extraction of DNA from Buccal swab. Restriction digestion with Ecor-1 from extracted DNA obtained from above mentioned source has been done for identifying individuals. Blood was used as a control and compared with DNA bands from buccal swab. A total of 10 wells were created. DNA obtained from blood wer e labeled as Ab, Bb,Cb, Db,Ebas shown in tab 3. DNA obtained from Buccal swab were labeled as Abs,Bbs, Cbs, Dbs, Ebs. DNA obtained from blood from 5 individuals was made to run in the well marked 1 to 5 in a uniform manner. But while running DNA obtained from buccal swab the order was changed randomly. For example DNA isolated from buccal swab for the first individual (Abs) instead of being run in the first well ie well No -6 was made to run in the fifth well( well no 10). Likewise DNA isolated from buccal swab of different individuals was made to run in different wells and the number of bands produced is identified Different methods of DNA extraction is been followed in that, most widely used is phenol chloroform method . Many new methods of DNA extraction have been tried. The chelex method is one among then . To know the efficacy of the chelex method it was compared with that of phenol chloroform method. Of the two methods studied the chelex method proved to be more easy to handle and less time consuming in addition to yieds higher amount of DNA and is proved by quantification with U. V spectrometer as shown in fig. 2. DISCUSSION: Forensic odontology is a branch of forensics which analyses stains and organic liquids from the oral cavity or its contents, bite mark comparison, investigation of trauma and oral injuries such as personal injury cases, and dental malpractice. The fundamental requirement of a criminal investigation is that the victim and aggressor should be positively identified. Forensic dentistry aids in the forensic process by comparing the deceaseds dentition with that of previous dental records or by facilitating to shape the profile of an individual in terms of age at the time of death, sex and phylogeny to aid in identification. 11,12 Saliva has been a potential source of identification and is usually found in bite marks, cigarette butts, betel quid, postage stamps, envelopes and other objects. The first phase of the study intended to isolate DNA from saliva (under different conditions), by phenol-chloroform method and chelex method and compare the yield with that of blood . The second objective was to find out efficacy of these methods in extraction of DNA from traces of saliva ie from Buccal swab, and from Betel quid and which could be used for forensic application. 8 The presence of residues are considerably important as biological evidences, but forensic analysis of such evidences has been hindered by failures in extraction of human DNA. Consequently, it is indispensable in forensic science to establish a reliable method for extracting DNA from samples collected at the crime site. The most important objective was whether individuals can be identifed from samples of different source and to ascertain the applicability of the restriction digestion in forensics. 13,14 Blood was taken as control, saliva was divided into 3 parameters ie from fresh saliva, from saliva stored at -20 degree for24 hr from saliva stored in room temperature for 24 hr’s were obtained . Identification of individual has been done with restriction enzyme EcoRI. . The isolated DNA was digested using the restriction enzyme EcoRI(G|AATTC)The digested DNA was run on 1% agarose gel electrophoresis and the bands produced in each individuals DNA were scored and is proved that identification of individual can also be done by DNA fingerprinting or profiling. Agarose gel electrophoresis separates DNA fragments according to their size. The most important objective was whether individuals can be identified from samples of different source and to ascertain the applicability of the restriction digestion in forensics. 16 DNA fingerprinting is a technique that is used to represent like and unlike DNA that is present in different individuals. Nucleotide sequences which show significant variation from one individual to another are taken into consideration. 17The most important objective of the study was to ascertain whether individuals can be identified from samples of different source and to ascertain the applicability of the restriction digestion in forensics and the last objective was toCompare the DNA yield from manual and kit method. To prove that DNA could be extracted from traces of saliva , Buccal swab and Beetal quid was used . DNA could be extracted from buccal swab,beetal quid and quantification was done with U. V spectrometer. Comparison of DNA isolated from all the samples collected from all the individual using two different procedures has been done and comparison of yield of different sources showed the kit method to be more effective . Use of biological evidences like saliva, buccal swab and betel quid are compromised due to the quandary in extraction of human DNA. The present study had proved to establish a reliable method for extracting DNA from samples collected from different sources of saliva and from traces of salivary stains which was comparable to bloodin proving identification. Samples collected from different sources of saliva and from traces of salivary stains can also be assessed by DNA fingerprinting or profiling which is based on the fact that DNA is unique to every individual .

Schottky Diode Lab Report

Schottky Diode Lab Report INTRODUCTION A Schottky diode is the common name for a metal-semiconductor junction, it is the work function between the semiconductor and metal that determines whether the junction is ohmic or rectifying [1]. This lab will focus on the fabrication of a Schottky diode and the characteristics they possess. In principle, Schottky diodes are rectifying as the current can only flow one way. They can also handle high frequencies and have lower power loss which makes them ideal for many applications [2]. These include being extensively used in power electronics, general purpose rectifiers and due to its non-linear I-V curves, it is able to be used as a varistor which in turn can be used for voltage suppression [2]. Also there is a low capacitance of the device which makes it more ideal than alternative diodes. OVERVIEW OF THEORY An Ohmic contact is needed on the bottom part of the sample as without this, any measurements taken would create a very high resistance as the semiconductor and the metal probe used to measure would create two diodes facing each other, therefore no current could flow. This is overcome by diffusing indium and germanium onto the semiconductor wafer. Gold is also used to prevent any oxidisation on the sample. The wafer is firstly placed into the tube furnace with the gold, indium and germanium on it then heated at 420 °C for 90 seconds. This is to enable quantum tunnelling so there is little resistance and only the semiconductor and top metal are measured. Figure 1 shows the energy band diagram of a metal-semiconductor junction, which is rectifying as the work function of semiconductor is higher than that of the metal. Figure two is the Schottky diode characteristics and when compared to figure 3, the PN diode characteristics, it shows that the turn on point is lower in the Schottky diode, which means less power is needed to operate, however there is a higher leakage current in reverse bias. DEVICE FABRICATION When working with such easily influenced devices, safety must be upheld at every milestone. This is first enforced by the dress code that is required in the laboratory. Each person must wear an overcoat, safety glasses, gloves, overshoes and a hair net. Due to e ven the smallest particles being able to affect each sample, the dress code is necessary to ensure that very little dust gets into the clean room. Also, there are many different chemicals in the room therefore more precautions are needed when working with them. All guidelines set out by the Control of Substances Hazardous to Health (COSHH) regulations must be vigorously followed. Using these guidelines, all chemicals must be used inside a fume cupboard as any spillages will be contained and the fumes can be collected. There are also hot plates and other specialised equipment that should be handled with care to ensure no damage comes to either the user or the machine itself. The cleanroom is comprised of 3 different areas. The first is where the entrants of the cleanroom put the safety equipment on, the second is the main laboratory area and the final is the yellow room. Each room is connected to the next with interlocking doors that only open when all others are closed.   This is because each has a different pressure level due to the need of having to keep as little dust in the main room to stop the contamination of samples. The high pressure level in the main room help to filter out any unwanted particles in the room. The air flow is also monitored to ensure that if there is a drop in pressure, the right actions can be taken to rectify any issues. The yellow room has special lighting due to the sensitivity of the devices that will be later described, however the main difference is that both red and blue colours have been taken out as the devices are easily affected by UV lights. The clean room being used for this experiment is classified as Class 6, this refers to the particle size compared to the maximum particle density. Once all safety aspects have been covered, the process to create the device can begin. The first step is cleaving. This is where the wafer is cut into small sample sizes, usually 3x3mm, as the wafer is very expensive and only a small amounted is needed to complete the experiment. A special machine can be used to perform this however it is also achievable by hand. When the sample has been cut to the necessary size, it is essential that a three stage solvent cleaning method is used. This is to ensure that there is little to no dust on the sample. To complete the three stages, the sample must first be placed into a beaker of N-Butyl Acetate (NBA) that has been heated on a hotplate. Once it has been in the beaker for a short amount of time it must be removed and then cleaned with a cotton swab that has also been dipped in the NBA. This is done by rolling the swab forward whilst pulling back so that as many particles as possible are collected. The sample is the turned 90 ° and swabbed again to collect any particles that may have been missed. This process is again completed but with the sample being dipped in Acetone and then Isopropyl Alcohol to complete the three stage cleaning. After this has happened, the sample is then dried with Nitrogen gas. Due to the small size of the sample, it is much easier to handle on a larger material, such as a glass slide. This is done by heating the slide on a hot plate then melting wax onto it then placing the sample on that. This is then left to cool and will now be ready for the next stage. The next stage is photolithography. This is required to put a pattern onto the sample so that testing of the device can happen and is exclusively completed in the yellow room. As mentioned earlier, the stages throughout this part will mean that the sample will be affected by UV lights so it is necessary to complete this in the designated room. Firstly, the sample is placed on a hot plate for one minute. Then it is placed onto the spinner and spun at 4000rpm for 30 seconds and dried with nitrogen gas. Now a few drops of photoresist are added, this is the solution our sample will be printed with. Again the sample is placed in the spinner 30 seconds and then soft baked on a hot plate for exactly 1 minute. If the sample is baked for too short, the sample will stick to the machine used in the next part and if baked for too long the sample may become damaged. Once the sample is completely dry, it is placed into the mask aligner. Each corner is lined up using the microscope and the camera s o that a complete pattern is across the sample. Once completed, the machine is set for 6 seconds and exposes the sample to UV light, the time needed varies with different materials. The sample is then washed in a beaker of developer solution for exactly one minute as again if the time is not strictly adhered to, it can have adverse effects on the sample. Finally it is washed in deionised water and dried with nitrogen gas. Now the sample has the same pattern which was imprinted from the mask aligner as the photoresist has been taken away from the parts that are needed. Now metallisation must happen as the sample needs a metal layer placed onto it. This is completed by placing the sample in a vacuum chamber and placing a small amount of aluminium inside a tungsten coil. Tungsten is used as the process involves heating the chamber to a point where the aluminium will evaporate but the other materials will not. As the chamber heats, the aluminium creates a thin layer across all of the inside of the chamber, this layer is approximately 0.2ÃŽ ¼m which can be calculated by knowing the amount of aluminium used. As the chamber is a vacuum, there will be no chance of an oxide layer being created which would ruin the sample. Using the vacuum also means that less pressure is needed and that a lower temperature can be used. Due to the evaporation covering the entire surface of the sample, the Lift-off process is needed to remove any parts of the metal that is not needed. The photoresist has protected some parts of the semiconductor from the metal and this needs to be removed to leave the parts where there is a direct contact between the metal and semiconductor. This is done by placing the sample in a beaker of acetone and syringing the sample until the photoresist, and the metal on it, is removed. This process is usually quite quick but can take anywhere up to 20 minutes. The final stage before the sample is ready for experimental observation is to remove the sample from the glass slide. This is completed by heating the sample on a hot plate until the wax has melted. Once this happens the sample is then cleaned with the same three stage solvent cleaning method earlier describe to remove any remaining wax. Finally it should be dried with nitrogen gas, with care taken as the sample could be blown away due to it not being on the glass slide. Once the all stages have been completed the sample is ready for analysis at the probe station. DEVICE CHARACTERISATION Now the slide is ready, the first test can commence. The sample is placed in the probe station and a Source measurement unit (SMU) is connected to the probe station and a computer so the results can be recorded. As the SMU acts as both the source and meter, this is connected to one probe whilst the base is connected to the other. Now the probe is carefully aligned onto one of the small circles that has been created on the sample, with great care being taken due to the sample only having a very thin layer which is easily penetrable. Next, a voltage sweep is created from -3V to 3V with a low current limit so ensure the device is not broken. Once the data has been recorded the probe is moved onto a different circle and the process is repeated. The behaviour of the Schottky diode can be modelled by the following equation: If the gradient of the voltage versus Log(J) is taken, the equation can be rearranged to find n. n is the factor that is used to determine the non-ideality of the diode. The values for the current density and n can be found in table 1. The next experiment is to measure Capacitance verses Voltage. The measurements will be taken in a similar way to the IV measurements however, a LCR meter will be used instead. This is due to the LCR being able to measure capacitance and phase angle. For these measurements, the sweep will start at 0 and be reduced until the phase angle is roughly 75 °. This is due to the need of being in reverse bias. The following formula can be used to find the dopant density of the semiconductor. The dopant density of the sample was found to be ***. The voltage barrier of each diode can be found by taking the gradient of the graphs. DISCUSSION AND CONCLUSIONS Reviewing the IV graphs it is clear that as the current increases, the linearity of the current density starts to become unstable. This can be explained due to the possibility of defects in the sample. In most industry practices, technicians are not present during the manufacturing fabrication stage and is solely completed by machines. Even though great care has been taken to ensure that the samples used in this exercise have been unaffected by unwanted particles, there is clearly still evidence of impurities throughout the sample. When the data from the CV graphs is reviewed, the observation that as the diameter of each diode increases, the barriers height decreases can be made. Having a higher barrier height is important as this will create a rectifying contact which is beneficial as it only lets the current flow one way. Therefore the conclusion can be made that having diodes with lower diameters have more advantages when creating Schottky diodes. This lab has demonstrated how a Schottky diode has been made and what the different characterises are. Great care has been taken to ensure little impurities affect the sample however there is still room for improvement and shows the essential need to uphold the safety requirements. Due to the low power needed and the fast switching abilities Schottky diodes are able to be used much more universally than standard PN diodes.

Preventing PC Issues :: essays research papers

Several people in the class have had "computer problems" in the last couple of weeks. This is often caused by Aware, Spyware, Malware, Viruses, and not maintaining the hard drive. Many times people will buy a new PC and 6-8 months later cannot understand why it is running so poorly. I rebuild a lot of computers for people. If it is a Pentium III or better and the person has all the original software that came with the pc, it is not a difficult task, although it can be time consuming. There are several things we can do to prevent this from happening. Defrag the hard drive weekly or at the very least once per month. Get the "red" out. (On an XP OS it is: Start-->All Programs-->Accessories-->System Tools-->Disk Defragmenter) Use a good virus program and keep it updated. Norton or Mcaffee are the most popular. A new-comer is PC-cillin by Micro Trends. They have a very good application that uses very little resources and they update their "dat" files much faster than the other big two, include a spyware search and have 24 hour phone tech support. Do a search on the internet. There are a lot of great articles by magazines such as PC Magazine written about this program and company. Norton and Mcaffee have not updated their engine in almost 2 years. Download Ad-aware and Spy Bot and use them weekly. These are free programs you can find with a simple Goggle search, download and install. The updates are free also. These programs will find most of the pesky programs you don't want on your computer. Back up your data. All your MS Office data files; .doc, .xls, .ppt .mdb, email, jpeg pictures, etc. If you have a CD burner, you can copy 750mb on each disk. If you have a DVD burner, you can save 4.7GB on each disk! Don't use "file-sharing" programs that allow you to download music, movies and applications from other people. You never know exactly what you are getting. I have seen some of the most evil stuff coming from these places. Besides, most of that is stealing anyway. Would you want to write or produce something only to see it all over the 'net right after its release? If you have a broadband connection, USE A ROUTER. I can't say it enough. With a broadband connection, Cable or DSL, you are on "open" IP address on the internet.

Provocation Through Comedy :: Movie Script Film Creative Writing Essays

Provocation Through Comedy If I were to write a film concerning women and sports, first of all I think I'd make it a comedy. I think sometimes it is easier to convey serious thoughts through a comedy, because the viewer doesn't feel so tangled up in the emotion of drama, leaving them laughing and in a good frame of mind to consider the points being made by the film after they watch the film. I think this idea is much akin to the idea that it is easier to discuss issues and problems of race and gender through a forum like film because a person can identify with an idea being expressed without having to take responsibility for the authorship of the idea. I think that a comedy is more capable of providing a powerful ending because the viewer isn't expecting it. Obviously if I were a screenwriter I would want to write a film that was unique and distinguishable from the other films made about women in sport. This might at first seem difficult, given the proliferation of films made on the subject, but they follow a lot of the same trends. One of these trends is the portrayal of the latent aggression in women that is released through sport. Women are not permitted by society to be aggressive in any area and still maintain their femininity. If I were to write a film I would include this theme and I would try to show that women can be aggressive in many areas. Their aggression can be in something other than sports, for example, business. I think a situation that would show this and also be comical could be perhaps a woman that owns a sports team. Another issue is the fact that all of the women in the films we watched were made to prove their femininity. I don't think that it is necessary to prove that a female athlete must stand up to an accepted level of femininity. There really is no reason to make a female athlete buy new dress shoes or learn to put on lipstick. I really don't think that it is necessary for any woman to prove their femininity whatsoever, especially not in these superficial, commercial ways. So if I were to write a film, she wouldn't go through that trouble. Her power suit could be pants and she wouldn't have to wear makeup.

americanisation of australian television Essay -- essays research pape

The Americanization of Australian Television is a sad and terrible thing. It is a process whereby ordinary Australians are bombarded every day with images of American lifestyle, so much that it merges almost unnoticed into their own lifestyle. It is a process whereby our home-grown entertainment industry is overwhelmed by the enormous powerhouse of the American economy, with drastic effects upon the modern Australian nation. Not only is Australian free to air TV being dominated by American produced shows, but a lot of the content on the Australian TV shows is sourced from America. American culture is part of Australian mass consumer culture, It dominates our television. If we look at the early history of Australian television, virtually all program material until 1963 was of foreign origin, of which eighty three percent was American and the rest British (Cited in an article by Cunningham Stuart ,â€Å"History, Contexts, Politics, Policy†.) Philip Bell discusses in his article that even in the first two decades of television ‘American programs and formats dominated commercial channels’ ( Cited in an article by Bell Phillip, ‘Television’). So Americanization of Australian television is not just a recent development. This problem has been there right from the beginning with American shows like Leave it to Beaver and I love Lucy dominating the TV screens of Australian households. Many are concerned with this issue, a good example is shown in an article written by David Dale, readers were asked if they were shocked by the revelation that all the most popular dramas and comedies on Australian television were made in America, and whether they thought TV stations should be forced to show more stories from other countries, including Australia. Carolina Peters talks about her concerns over this issue, she quotes, â€Å"I am not at all shocked that so much of the drivel on our TV screen comes from the US. I am, however, deeply concerned that so much of our programming is either direct from or heavily influenced by the US. The influence is clearly seen in the way kids today are affecting US accents and using US terms. I have heard many kids lately referring to their mothers as 'mom' instead of 'mum'.† ( Cited in the Sydney Morning Herald, David Dale).Whilst people like Terry North disagreed, Terry North talks about how the Australian networks should not be for ced to show mo... ...ence, and now talk and act like American teenagers. Australian television is threatened by the influx of American culture. Phillip Bell talks about the rise of Australian ‘soaps’ in his article, for example Neighbours which began in 1985, he talks about how the show deals with ‘Australian’ issues. (Bell Phillip, ‘Television’), this isn’t necessarily true. In fact many of the storylines in Neighbours are taken from American soaps like Day of our lives or Bold And The Beautiful. Our screens are increasingly filled with disturbing storylines which continually push the boundaries of human depravity. Australian commercial television has imported American formats (Bell Phillip, ‘Television’). Even the Australian Logies are becoming Americanised. At the 2005 Logie awards, there were at least two American celebrity guests, CSI Miami actress †¦Ã¢â‚¬ ¦ was given a lot of attention at the Logies, because of her famous American celebrity status. The Logie awards which were supposed to be awarded to shows that are produced in Australia, this year awarded a Logie to the OC for the best overseas program. The influence of the American culture on Australian television was clearly evident at the Logies.

Killings by Andre Dubus Essay

â€Å"Killings† by Andre Dubus is a short story about a father who seeks out vengeance for the murder of his twenty-one year old son only to learn that revenge will only make things worse. The father, Matt Fowler, is haunted by the tragedy that has befallen his youngest son. Retribution is a common human desire because people feel that it offers the truest form of justice; however, this action is against the law of the land and is thought of as reckless to pursue. The author uses foreshadowing, imagery, and dialogue to illustrate a tone of prudence when thinking of taking vengeance into one’s own hand. In the story the literary element of foreshadowing is used. The desire to get even is an emotion that is felt by all people and is not biased as to who feels it. That desire is displayed at the beginning of the story. This is shown when the author writes, â€Å"Matt’s older son, Steve, turned to him as the family left the grave and walked between their friends, and said: ‘I should kill him’† (1203). This ominous statement shows how the feeling of revenge causes the character to not think of the consequences when pursuing vengeance for what is thought of as true justice. The writer further establishes how the feeling of retribution clouds cautious thinking through foreshadowing when he writes, â€Å"‘I’ve got a . 38 I’ve had for years, I take it to the store now†¦She knows I started carrying it after the first time she saw him in town. She knows it’s in case I see him and there’s some kind of situation. ’† (1204). This indicates that not only is revenge to be sought out but also the means by which Matt Fowler plans to exact his vengeance without any thought of consequence. The author’s use of imagery creates a picture of how the father’s vengeance for his son’s murder takes place when Matt waits on the murderer to get off of work so that he can take the killer and his car back to the killer’s house. The author describes the scene with vivid detail when he writes, â€Å"†¦he stopped and aimed over the hood at Strout’s blue shirt ten feet away†¦They drove across the empty front lot and onto the road. Willis’s headlights shining into the car; then back through the town, the sea wall left hiding the beach, though far out Matt could see the ocean; he uncocked the revolver: on the right were the places, most with their neon signs off, that did so much business in summer†¦the street itself empty of traffic†¦Ã¢â‚¬  (1209). The description of the abduction of the killer creates a mental picture to the reader of how the father planned to obtain the murderer and exact his revenge. The use of magery is also evident when the author describes the preparations taken for getting even when the author writes, â€Å"Beyond the marsh they drove through woods, Matt thinking now of the hole he and Willis dug last Sunday afternoon†¦as they dug into the soft earth on the knoll they had chosen because elms and maples sheltered it† (1210). The prose writer not only creates a picture of how the father obtains the murder to exact retaliation but also where the killer would be disposed of. The author uses imagery to show that the character had plenty of opportunities to have second thoughts of seeking vengeance but used no caution and thought only of revenge. The author’s use of dialogue enhances the tone of caution when thinking of taking vengeance outside of the legal system. This is apparent in the father’s reply to the murderer when the author writes, â€Å"‘You’re not going to jail’† (1212). Matt Fowler’s response to the killer not going to jail through dialogue shows that he has no intentions of letting the justice system handle Strout’s punishment. The author further reinforces the tone through dialogue when he show’s the father’s distaste with the legal system. This is illustrated when the scribe writes, â€Å"‘I’ll do twenty years, Mr. Fowler; at least. I’ll be forty-six years old. ’ ‘That’s nine years younger than I am,’ Matt said†¦Ã¢â‚¬  (1214). The father’s response gives the reader insight to Matt’s thoughts of true justice and how no caution was used when pursuing this course of action. In conclusion, the author uses foreshadowing, imagery, and dialogue to set a tone of caution when thinking about taking vengeance outside of the legal system. This desire for reprisal is all too common, especially to those who have been victimized, to feel that if one wrong is committed that another wrong will cancel it out. Revenge is ill advised by most as people who say two wrongs don’t make a right and the memories will never fade. The story, â€Å"Killings† by Andre Dubus, illustrates how a father seeks out revenge for the murder of his twenty-one year old son and takes matters into his own hands only to discover that revenge only makes matters in his life worse.

A Culture of Resistance: The Chipko Movement

Society as a collective entity could easily influenced an individual but in the same manner the society could also be shaped by people. This is exemplified through the idea of cultutral resistance which is a political activity that enables individual to create or change political discourse and eventually political practices (Duncombe, 2002). The Chipko Movement of India is a good example to better understand this.The Chipko Andolan also known as hugged the trees movement is an environmental activist that started in the grassroots level. Its origins could be traced back in March 1973 at Gopeshwar   in the Chamoli district, in Uttar Pradesh, India.A group of citizens hold each other hand in hand to create a human chain and hugged the trees to prevent a sport company from cutting it down. The same incident took place in the village of Reni in the Himalayas during the year 1974.Women coming from this village also protected the trees by hugging them despite the license given by the Gove rnment Department of Forests that enables the contractors to cut them. Ever since the Chipko Movement attracted attention coming from other people in India (Dwivedi, 1996).The Chipko Movement addresses the problem of inequality that is happening in the distribution of natural resources. The usage of commodities like trees creates a conflict in the country of India because of the contradicting demands for it. The marginalized minority utilizes this resource as a means that would support their livelihood. On the other hand, trees are needed in order to address the demands of commerce and industry (Shiva & Bandyopadhyay, 1986).The inequlity in this situation is not only in terms of the unequal distribution of natural resources but also in terms of the power and influence that big corporations have as compared to the marginalized citizens of India. It is something that usual political practices could not solve and sometimes even tolerate as in the case of the 1974 incident in the Reni V illage, which is why the Chipko Movement decided on a new method of addressing the problem.In order to fully comprehend this movement as well as the tactics that it utilized there should first be an understanding of Mahatma Gandhi's ideology when it comes to conflcit as well as the diverse religion of India. Gandhi is famous for leading non-violent forms of struggle that overthrew the colonial rule of the British in India.He was able to combine the idea of â€Å"ahimsa† meaning â€Å"no harm† or â€Å"wanton killing†Ã‚   with social struggle. This non-violent activists deems that the truth will eventually emerged as long as one party is committed in standing for it (Kamieniecki, 1993).Gandhi's â€Å"Satyagraha†or the search for truth was adapted by the Chipko movement through the â€Å"Forest Satyagraha† which means the continuous search for truth in terms of the rights of trees. This movement follow the idea of non-violence in fighting for their c ause that goes as far as including non-human forms (Dwivedi, 1996).Forest Satyagraha does not only answer economic and environemtal problems because it also has its religious aspect. The major religions in India promotes compassion for all life regardless of its contribution to human beings (Kamieniecki, 1993). Its religious basis also comes from the fact that this movement is participated and led by women. Women play a very vital role in the family particularly in the Himalayan area.They are more in touch with the natural environment because they have the task of gathering woods and other agricultural products for their family while their spouses leave them behind to work in urban areas.Himalayan women are also more religious than their male counterparts which is why they believe that green trees are the dwelling place of â€Å"Hari† or the Almigthy Father. Every tree has their own â€Å"Vriksadevata† or tree god and that the goddess of the forests, â€Å"Van Deviâ⠂¬  will assure the safety of their family (Dwivedi, 1996).Mahatma Gandhi strongly believes in the importance of India's various values and cultures. He deems that the problems they are facing could find its solutions in the very ideals that they have. His concept of â€Å"Satyagraha† which was later on used by the Chipko movement as â€Å"Forest Satyagraha† is a clear example of how non-violent form of resistance could work against unequal and cruel foes like large corporations.This method that they have utilized is rooted in the very culture of India which is their strong religious belief that gives importance in valuing all forms of life (Dwivedi, 1996).The tactics that was used by the Chipko Movement tends to reform the issue of inequality in the local and structural level. It is well-known that Hindus practice the caste system wherein its citizens are divided according to particular groups (Perez, 2004).This kind of structural system already paved the way for ine quality to propagate. There are people who enjoy the privileged and powerful position and those who are marginalized. Being the case, inequality in the distribution of natural resources is bound to happen with such kind of system.The Chipko Movement strives to change this very inequality that is embedded within India's structure and it became evident in a more localized level in the issue of logging. This movement started tackling inequality in the issue of the utilization of trees in the grassrootsbut this problem is just an effect of what is really happening in the structural level.Their actions started in giving immediate response in what is happening in the local level but the attention it acquired enabled it to highlight the root cause of the problem in the upper level. It does not only stop within the state institutions of the Indian government but it also reach the international level.Many states are using the ideals of   the Chipko movement as an example on how the pressin g problems in ecology and environmental sustainability could be deal with. (Agarwal, _).Using a non-violent method to addressed the causes that the Chipko Movement is advocating for reflects that they decided to take a different approach in solving problems. It is an approach that   embodies their very culture and ideals.Their understanding of the problem is dependent upon the thinking that its solution would come from these factors that they uphold. This is supported by Gandhi's same belief in the power of India's rich cultural heritage and its capability to solve the dilemma that their country has (Dwivedi, 1996).This social movement greatly believes in non-violence and the preservation of all forms of life. These beliefs influence their understanding of the problem and the path that they chose to addressed it.They saw the importance of trees in their livelihood that is why they protected it through the embraced tree tactic. This non-violent form of resistance symbolizes their u nderstanding that to be able to solve this dilemma compassionate means should be practiced.If they decided to find solution to the problem by using adversarial tendencies then they contradict the very ideal that they are fighting for. It is the Gandhian principles of â€Å"ahimsa† and â€Å"satyagraha† that they based their movement on. They have to uphold these principles in the decisions that they make and in the actions that they take.