Friday, November 29, 2019
9th Grade Science Fair Projects
9th Grade Science Fair Projects 9th grade is the first year of high school, so 9th graders might be competing against older students in a science fair. Even so, they stand every bit as good a chance of excelling and winning. The key to success is choosing an interesting project that doesnt necessarily take a lot of time to complete. 9th graders have a lot going on, so seek an idea that can be developed and completed over the space of a few weeks or less. The quality of the presentation is very importantà since high school students are expected to be familiar with word processing programs and printers. Give some attention to the quality of the poster. Be sure to cite any references used in developing the experiment. 9th Grade Science Fair Project Ideas tooth whiteners s of chemicals to try would include hydrogen peroxide solution, dilute hydrochloric acid solution, dilute isopropyl alcohol solution, fruit juice. Some of these agents are thought to be able to loosen the seed coat surrounding the plant embryo.hair conditioner - Use a microscope to determine whether hair conditioner affects the condition of hair (either comparing brands or comparing with conditioner to without-conditioner). Try to get empirical data, such as a diameter measurement of each hair strand and the distance a strand can stretch before it breaks.What is the best way to store bread to keep it fresh the longest time? What things can you do to improve the efficiency or effectiveness of your clothes dryer or water heater or any device? For example, can you take actions or make changes that will decrease the length of time it takes your dryer to get a load of towels dry?Does listening to music while you study affect your ability to memorize facts?Does the presence of smoke in the air affect plant transpiration?Does eye color affect peripheral vision? Supposedly people with darker eyes tend to have wider pupils for a given amount of light than people with light-colored irises. If you have a more open pupil, does it give you measurably better peripheral vision? Another idea to test would be to see if you have the same peripheral vision in bright light as compared with dim light.acid snow? - You know about acid rain, but do you know the pH range of snow? If you live in an area with snow, test its pH. How does the pH of snow compare with the pH of rain from the same region?What methods of preventing soi l erosion work best? For example, what is effective at preventing erosion in your yard? What can you do to reduce noise pollution in a room? What factors contribute to noise pollution inside a residence?seed viability - Is there a test you can perform to predict whether or not a seed will germinate? What factors can you measure that might be used to construct a test?Does an external magnetic field have any noticeable effect on animals such as brine shrimp, cockroaches, or fruit flies? You could use a strip magnet and containers of sample organisms and make observations to address this question.Is the brightness of glow-in-the-dark (phosphorescent) materials affected by the light source (spectrum) used to make them glow or only by the intensity (brightness) of the light? Does the light source affect the length of time a phosphorescent material will glow?Can you affect vitamin C (or another measurable vitamin) levels in juice (or another food) by adding a preservative to the juice?What is the best thickness of insulation for preventing heat loss?Is light bulb lifespan aff ected by whether the bulb is run at full power? In other words, do dim bulbs last longer/shorter than bulbs run at their power rating? What type of box material gives you the best sound for your speaker?When comparing different brands of batteries, is the battery that lasts the longest at a high temperature the same brand that lasts the longest at a cold temperature.
Monday, November 25, 2019
Plural Nouns Forms
Plural Nouns Forms Nouns are words that indicate objects, things, places and people such as: computer, chair, beach, janitor, etc. Nouns are one of the eight parts of speech in English. Nouns that speak about objects you can count have two forms: the singular and the plural. This guide to the plural noun forms will help you understand how to make regular and irregular noun plurals. There are also irregular verb forms in English that need to be studied, as well as changes in the comparative and superlative forms that are very similar to the plural changes in noun forms. Regular Noun Plural Forms - Just Add S For most nouns, just add s to the end of the noun. singular noun s plural noun computer - computersbag - bagsbook - bookstable - tableshouse - housescar - carsstudent - studentsplace - placesetc. Irregular Noun Plural Forms - Nouns Ending in Consonant Y Nouns that end in a consonant y drop the y and add ies to the end of the noun. singular noun - y ies plural noun baby - babiesparty - partiespaddy - paddieshobby - hobbieslady - ladiesferry - ferriessherry - sherriesdandy - dandiesetc. Irregular Noun Plural Forms - Nouns Ending in SH, Ch, S, X, or Z For nouns that end in sh, ch, s, x, or z, add es to the end of the word. singular noun ending in sh, ch, s, x or z es plural noun beach - beachesbox - boxeschurch - churchesbuzz - buzzesloss - lossesfox - foxeswatch - watchesdress - dressesetc. Irregular Noun Plural Forms - Nouns Ending in O Many nouns that end in o proceeded by a consonant require an e before s to be placed at the end of the word. Unfortunately, there are also nouns that end in o that do not require changes. To begin with, here are examples of nouns that do need to change. singular noun ending in consonant o es plural noun tomato - tomatoeshero - heroeszero - zeroespotato - potatoesecho - echoesetc. Other nouns that that end in o proceeded by a consonant DO NOT require an e before s to be placed at the end of the word. Nouns ending in o proceeded by a vowel do not change. kilo - kilosradio - radioslogo - logospiano - pianossolo - soloscargo - cargoshalo - halosetc. Unfortunately, there is no clear rule as to when to add an es or just s. These plurals need to be learnt on their own. Irregular Noun Plural Forms - Nouns Ending in LF Nouns ending in the consonant combination lf drop the lf and end in ves. singular noun ending in consonant lf - lf ves plural noun leaf - leaveshalf - halvesself - selveswife - wivesknife - knivescalf - calvesshelf - shelveswolf - wolvesetc. Irregular Noun Plural Forms - Different Spellings There are a number of irregular plurals that change spellings in different ways such as man to men and ouse to ice here are some of the most common: man - menwoman - womenchild - childrenfoot - feetperson - peoplemouse - micetooth - teethdie - diceetc. Animal Plurals There are many animals that have irregular plural forms. Some animals do not change when forming the plural. deer - deerfish - fishsheep - sheeptrout - troutsquid - squid Other animals change form in the plural. mouse - micegoose - geeseox - oxenlouse - lice Irregular Noun Plural Forms - Nouns That Remain the Same in Singular and Plural Nouns that do not have a plural form are also known as uncountable or non-count nouns. These nouns include concepts, materials, liquids as well as others. concepts: advice, fun, honesty, information, ambition, etc.materials: steel, wood, plastic, stone, concrete, wool, etc.liquids: water, wine, beer, soda, oil, gasoline, etc. Still other nouns remain the same whether in the singular or plural. These nouns take the plural conjugation of tenses, but remain the same spelling. Here are some examples with sentences to indicate the difference between singular and plural usage. crossroads - crossroads There is a crossroads at the end of this street.There are a number of crossroads between here and downtown. series - series The new series about a robot is great.There are four new series on ABC this month.
Thursday, November 21, 2019
STAT Essay Example | Topics and Well Written Essays - 250 words
STAT - Essay Example Thus, we will look at Census records for each decade to discover whether the percent increase or decrease within the city (primarily Manhattan, though also some of the other districts) has gone up or gone down. This will be followed up with other possible variables or explanations and reasoning behind the end-result. There has been much speculation already about the effects of the terror attacks. The overall conclusion seems to be, in a more conceptual sense, that it "united" the country. My group was more curious about what the direct affects were. In the moment, the attack was successful. It created mass panic and many people, not just Americans, felt a great sense of shock, fear, and then loss. After the loss of the Twin Towers, which second only to the Statue of Liberty and the Empire State Building was a symbolic representation of New York, the city lost one of its great monuments. If the Twin Towers stood for New York, would their loss or destruction symbolize the loss or destruction of the city? As this paper will focus on the affect that 9/11 had in regards to population, this will be a somewhat limited investigation, only focusing on aspects that may represent residential situations. A large handful of articles have reported and presented the fears, substantiated or not, that many residents may have felt regarding the attacks. The Federal Government added cancer to a list of health problems caused by 9/11, with suggestion that debris from the Twin Towers was carcinogenic. Issues such as this could have serious effects on the population in Manhattan, especially in the Ground Zero area. Thus, according to The New York Times, "New York City health department [initiated] studies [which have] found no clear link between cancer and the dust, debris and fumes released by the burning wreckage of the twin towers" (Hartocollis). The study
Wednesday, November 20, 2019
Galileo and Aristotle on falling bodies Essay Example | Topics and Well Written Essays - 1000 words
Galileo and Aristotle on falling bodies - Essay Example Aristotle explained how objects fall, he stated that every object has a natural place and if the object is moved it will move back to the natural place. Aristotle was among the first early scientists to quantitatively think about speed of a moving body he came up with to assertions on natural motion of free fall 1. Speed of a falling body is proportional to its weight i.e. heavier bodies fall faster than light ones. 2. Speed of a free falling body is inversely proportional to the density of the medium it is falling through Aristotle did not put into consideration a vacuum because it would be incompatible with his thinking. The inference deduced from his theories shows that objects experience less resistance with increase in speed therefore, in a vacuum an object would move infinitely fast. A study of moving objects led Aristotle to the conclusion that velocity, for a given force was inversely proportional to the density of the medium. In modern science this is v=k/d where v, speed is a function of density d and k is a function of proportionality. He explained acceleration as an objects response to its natural place. He states that since the object ââ¬â¢knowsââ¬Ëitââ¬â¢s final destination it keeps going faster until it gets there. To Aristotle two objects of different kinds in a similar medium would not have similar acceleration as the heavier object overcomes resistance of the medium and would thus fall faster than the lighter object. Aristotle obtained his results from pure observation he did not subject any of his theories to any experimental or mathematical scrutiny he also did not have any methods at the time to create a vacuum or reduce friction in order for him to notice dependency on density. Frictionless uniform motion was not analyzed by Aristotle, he considered motion under constant force acted upon by friction, and he concluded that a constant force must be applied on a body to overcome effects of friction force. Galileo - He was the first p erson to publicly and experimentally observe and prove discrepancies with Aristotleââ¬â¢s predictions one of his first experiments was on motion of bodies on free fall it was a challenge to Aristotleââ¬â¢s motion theories, Galileoââ¬â¢s approach to science was different from Aristotleââ¬â¢s he can be referred to as the father of modern science, he concentrated on describing a problem mathematically first, before coming up with a conclusion , he assembled relevant information and created a coherent pattern to disapprove Aristotleââ¬â¢s assertions. He carried out quantitative results rather than describing observations qualitatively, he speculated that in addition to gravitational force acting on a free falling object there was a counter upward force exerted on a falling object by the medium it is falling through. Galileo came up with experiments to show this phenomenon. He used water as the medium to make motion of object through it relatively slow in order for him to record time taken by each object. With this experiment he discovered 1. Heavy objects that are streamlined reached the bottom of experimenting tank at approximately the same time only a little bit longer than time taken to cover a similar height in air 2. Lighter and less streamlined objects took more time to reach
Monday, November 18, 2019
Structures Essay Example | Topics and Well Written Essays - 1000 words
Structures - Essay Example The bridge was built to a scale of 1 to 40 with total clearance span of 500mm, utilizing craft sticks and PVA glue. After building of the bridge, it was tested to eliminate fatigue failure via application of the mid span within a laboratory setting. Moreover, the collapse is the position at which the underlying structure cannot support further escalation of load or a deflection beyond 30mm. The prevailing truss bridge passes the failure test. Moreover, the greatest load of 3.5kN was the second load applied to any bridge test, which excessively exceeds the needed load of 98N by the corresponding factor of 36. The prevailing weight ratio of 11.7 was compared satisfactorily with the existing supplementary bridges tested to enable successful design. Nevertheless, the graph of the load against deflection was not ideal thus depicting defects within the construction as depicted by the failure of the bridge. Advanced bridge possess relatively greater links amidst the prevailing craft sticks by utilizing sturdier clamps thus will improved the bridge by offering greater quality links amidst the underlying middle trusses and the corresponding bottom beams to avert it from slipping out. Bridges are observable accomplishments of engineering presently. Originally, the bridges composed of relatively simpler structures purely made from easily reachable natural resources. The natural resources entail timber, stone and dirt, which were operational though they had shorter life span thus resulting to weak structural bridges. Conversely, modern designs for trusses possess greater spaces to be spanned. A truss design is normally favorable to numerous engineers in modern world, since they are affordable and have high structural integrity. Comprehending structural behavior of any bridge is a significant aspect of engineering. This is because it aids in comprehension of the concepts of load transfer via the structure by tension and compression and corresponding equilibrium
Saturday, November 16, 2019
Diagnosis of Systemic Lupus Erythematosus (SLE)
Diagnosis of Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a multi-systemic autoimmune disease that was first described in 1941, by Klemperer and colleagues (Gonzalez-Buitrago and Gonzalez, 2006). It is a disease that can attack almost any organ or system in the body, where imbalances in self tolerance create an abnormal immune response to self proteins resulting in autoimmunity (Male et al, 2006). SLE is a disease that has a strong correlation to defects in apoptosis; however no specific cause of the disease is known (Arbuckle et al, 2003). The prevalence of the disease is worldwide; however it commonly affects people of African descent, particularly in Europe and Northern America (Kumar et al, 2009). Environmental triggers are known to contribute to the disease manifestation; although genetic links have also shown association with all HLA classes (I, II, III) on chromosome 6. Other transcription factors such as IRF5, STAT and proteins such as PTPN22 have also been seen to contribute to the manifestation (Mal e et al, 2006). SLE is particularly common between the ages of 15-50, where patients present with positive antinuclear antibodies (ANA). ANA are a group of heterogenous antibodies that are capable of binding to components of the nucleus, resulting in damage of DNA. The initial screening method for patients with AIDs such as SLE is via the ANA test. 80-90% of patients with SLE present with a positive ANA (Bonilla et al, 2007), however other AID such as Sjà ¶grens syndrome, Rheumatoid arthritis, Autoimmune hepatitis, Scleroderma and Polymyositis Dermatomyositis, also see positive results. Antigen specific assays such as extractable nuclear antigen (ENA) and double stranded DNA (dsDNA) must then be performed to confirm a diagnosis, as approximately 70% of patients with SLE have antibodies to dsDNA (Rahman Isenberg, 2008). Positive results can be seen within the aging population as the immune system begins to deteriorate. Nilsson et al, (2006) supports this and found that positive ANA results were fo und particularly in elderly patients over 85 years. 90% of patients with SLE are women, suggesting a hormonal link (Rahman et al, 2008). Hormonal imbalances are seen in women with SLE, thus it becomes difficult to maintain immune tolerance. Increased oestrogen levels result in increased antibody production and Th2 response, whilst decreased levels of androgens depress the response resulting in an abnormal immune response (Danchenko et al, 2006). 1.2 The clinical significance of ANA testing The diagnosis of SLE is dependent on a variety of factors including clinical details, family history, age, race, sex, medication and infection (Stinton Fritzler, 2007). The classical symptom for SLE is a butterfly-shaped rash which is commonly seen on the face (Figure 1.1). In 1982 the American College of Rheumatology (ACR) described a set criterion (Table 1) (updated in 1997), for the diagnosis of SLE aiding clinicians to correctly diagnose patients. Four points of the criteria must be met, for a definite diagnosis of SLE. The criterion for SLE includes symptoms, immunological and haematological tests. Points 10 and 11 are of particular importance, as they are confirmatory of SLE. A study by Arbuckle et al, (2003) examined the onset of SLE in 130 patients and found that 115 patients had positive indirect immunofluorescence (IIF) ANA, before diagnosis. 1. Malar Rash A butterfly rash usually seen on the face 2. Discoid rash red, scaly patches on skin that cause scarring 3. Photosensitivity Skin rash as a result of unusual reaction to sunlight 4. Oral ulcers Oral or nasopharyngeal ulceration 5. Nonerosive Arthritis tenderness or swelling of joints 6. Pleuritis or Pericarditis Pleuritis inflammation of the pleura, the lining of the pleural cavity surrounding the lungs Pericarditis small amount of fluid builds up between the two layers of the pericardium. 7. Renal Disorder Persistent proteinuria Cellular castsmay be red cell, hemoglobin, granular, tubular, or mixed 8. Neurologic Disorder Seizures 9. Hematologic Disorder Hemolytic anemiawith reticulocytosis Leukopenia Lyphopenia Thrombocytopenia 10. Immunologic Disorder Anti-DNA: antibody to native DNA in abnormal titer Anti-Sm: presence of antibody to Sm nuclear antigen Positive finding of antiphospholipid antibodies on: 11. Positive Antinuclear Antibody An abnormal antinuclear antibody by immunofluorescence Once a positive ANA test has been performed there is no reason to repeat the test, however if clinicians have a strong suspicion of an evolving connective tissue disease (CTD) negative ANAs should be re-requested (Blerk et al, 2008). Other immunological tests such as complement components (C3 and C4), C-reactive protein, anti-phospholipid antibodies and anti-histone can also be tested to investigate SLE; however these may not always aid all patients (Egner, 2000). 1.3 History of ANA testing and how the diagnosis of SLE evolved The ANA test has been around for over 40 years and is the most widely performed autoantibody test, worldwide. The test is commonly performed within Immunology laboratories and has evolved very little over the years. ANAs originated from lupus erythrocytosms, also known as the LE cell phenomenon. LE cells were discovered in 1948 by Hargrave, who saw that patients with SLE have polymorphonuclear leukocytes, which had phagocytosed nuclei, within the bone marrow (Hepburn, 2001). Following the discovery, Lee et al, (1957) showed that the LE cells were formed by gamma proteins in leukocytes which were thought to be antibody. Fluorescent labels were also introduced in 1957, to show homogenous patterns on human tissue (Hughes et al, 2008). By 1961 rat sections substrates were introduced, enabling patterns such as homogenous, speckled and nucleolar to be seen in patients with rheumatic diseases. The use of rat substrates brought about a new discovery, which saw that washing cells in saline, c aused alterations to cells within slides, thus altering patterns seen, thus the precursor of the ENA screen was introduced. By the 1970-80s Human epithelioma type 2 cells: CCL-23 (HEp-2) substrates were widespread and National quality assurance schemes began to establish. 1.4 Techniques implemented in laboratories for ANA detection There are many techniques available for the testing of ANAs; these can be seen in the UK National External Quality Assessment Service (UKNEQAS) report found in Appendix 1. 1.4.1 Indirect immunoflourescent (IIF)-ANA Indirect immunoflourescent (IIF) is a general screening technique performed to identify patients with autoantibodies. It enables scientist to link autoantibody patterns present within a patient sera, to help diagnose and monitor their progress during treatment. ANA testing using IIF was developed by George Friou in 1957, where initially substrates such as chicken erythrocytes were used (Kumar et al, 2009). ANA substrates were traditionally prepared in-house using rodent tissue where thin layers of tissue were sliced using a cryostat. However as demand for the screening of autoantibodies increased (Figure 1.2), preparing slides was no longer feasible, as it was time consuming and laboratories could no longer manage rodent houses as they required expert attention. Commercial companies then began to produce ready to use tissues substrates, offering a greater sensitivity. However as many commercial substrates are now available, variability between kits, manufactures, substrate, conjugate and the degree of cellularity (good monolayer of cells and a number of mitotic spindles), make it difficult to standardise methods of detection and reporting. In order to produce accurate results, substrates must be present in the correct phase of the cell cycle (Figure 1.3). Identification of IIF-ANA patterns is dependant on the true state of chromosome. Most autoantibodies are directed against antigens expressed during interphase. Interphase is divided into 3 stages: G1, S and G2, where cytoplasmic organelles and fibres structure are most visible and the nucleoli appear well differentiated. A mix of mitotic and non mitotic forms of cells are needed in the metaphase stage as it is influential in interpreting IIF-ANA patterns, especially centromeres and homogenous patterns (Sacks et al, 2009). The HEp-2 substrate is commonly used in ANA detection and was introduced commercially in 1975 (Kavanaugh et al, 2000). HEp-2 provided a greater sensitivity for the testing of SLE as they were composed of human laryngeal squamous cell carcinoma, allowing the recognition of over 30 nuclear and cytoplasmic antigens (Gonzalez-Buitrego Gonzalez, 2006). HEp-2 substrate contains various organelles (Figure 1.4) allowing uniform distribution of cells, showing large nucleolus, meaning no interference of the intercellular matrix is seen (Gonzalez et al, 2002). The introduction of the HEp-2 substrate was a big step forward in identifying patients with the ribonucleoprotein complex (anti-Ro). The anti-Ro antigen is particularly significant in patients with SLE as it offers a poor prognosis. However this antigen is seen to overlap between different autoimmune diseases such as Sjà ¶grens syndrome, thus the detection of the antigen must be precise. The Ro (SS-A) antibody is seen to target protein antigens associated with small RNA molecules known as hY-RNAs11, 12 and are of unknown function (Cozzani et al, 2008). HEp-2 cells were seen to destroy the Ro antigens during fixation, so commercial companies began to devise ways around this. To overcome this problem, HEp-2 cells were genetically modified to produce extra Ro antigen and this substrate was known as HEp-2000. HEp-2000 substrate is uniquely produced by ImmunoConcepts (Sacramento CA, USA). The slides have 10-25% mitotic human epithelia and offer a greater sensitivity (Table 2) in the diag nosis of SLE. They have aided in reducing the number of ANA negative SLE patients; however detection of Ro is dependent on the stability of actin, as it can denature easily. Although HEp-2000 substrates were seen to be more beneficial in detection of Ro antigen, they limit the identification of the different epitopes of the Ro antigen. At present HEp-2000 substrate can only identify the 60kDA Ro antigen; but since the 52kDA Ro antigen also exists, patients with this epitope are missed. A study by Cozzani and colleagues (2008) looked at 5,949 people over a 5 year period. All participants were photosensitive and 2,315 of these had connective tissue disease (CTD) such as SLE. The study found that the anti-Ro was easy to identify on HEp-2000 slides with a sensitivity of 81% according to the Altman test, of accuracy. However a study by Bossuyt and Luyckx (2005) compared IIF to EIA and saw that patients with anti-Ro antibodies were missed using HEp-2000 slides, as the undetected patients contained the Ro 52 antibody; although they reported a sensitivity of 82.9%. One patient in this study was negative for IIF-ANA, but was shown to have a positive Ro antigen by EIA. A study by Dahle et al, (2004), looked at HEp-2 and compared three ANA methods; Enzyme immunoassay (EIA), double radial immunodiffusion (DRID) and IIF. 3,079 patients were examined and overlapping results between IIF and DRID were seen and 60% of IIF-ANA gave a positive homogenous pattern. However results for EIA showed that positive IIF results appeared negative by EIA. In 2006 the LGI performed a study looking at 18,320 samples, requesting ANA tests by IIF. The study found that 1 in 5 patients, identified as negative or weak positive by IIF, showed positive for anti-Ro via EIA. This proved that Hep2000 cells cant detect the different epitope of Ro, thus concludes that antigen-specific testing is required following the ANA test. This agrees with Morozzi et al, (2000), who suggest that a combination of 2 or more methods are required for the detection of the anti-Ro antibody in patients. This study looked at 64 people with connective tissue disorders and tested them by IIF, EIA and DRID. Results showed that 54 people were positive by at least one method and the specificity of each technique was good, whilst sensitivity varied. Sensitivity for IIF-ANA via HEp-2000 was 89%, EIA (Ro60) was 89%, EIA (Ro52) was 67% and DRID presented with a sensitivity of 76%. Although the NEQAS report shows that DRID is no longer used within laboratories, results from thi s study suggest that EIA has the ability to detect the different epitopes, preventing misreading of the anti-Ro antigen. Thus to ensure that all SLE patients are identified antigen-specific tests such as extractable nuclear antigen (ENA) should be used to detect the various epitopes (Cozzani et al, 2008). Conjugates play a significant role in the determination of IIF and EIA results. Fluorescein-conjugated antibodies produced from goat, sheep or rabbit are commonly used. These are usually bought from commercial companies, which produce pre-diluted conjugate, raised against mouse or human, which aims to achieve optimal sensitivity and reactivity. Immunoglobulin fraction can be also be used; however fluorescein conjugates such as fluorescein isothiocyanate (FITC) are preferred as they produce less background staining. A fluorescein/protein (FP) molar ratio is employed, with in-house diluted conjugates. The ratio varies between kits, however a 1:3 dilution with phosphate buffered saline (PBS) is usually used (Egner, 2000). At LGI the conjugate used for detection of ANAs is IgG, as it allows accurate diagnosis and monitoring of diseases such as SLE. IgM-ANA can also be employed, although this indicates milder or non-specific diseases, whilst IgA-ANA gives little information so arent used. Due to the use of fluorescence conjugate, slides fade overtime, thus it is particularly important to determine results as soon as possible as photographs are not taken. As IIF varies daily due to slides and condition of the microscope, it would be appropriate to carry out daily checkerboards to see which working dilution is best for the conjugate, improving consistency; however this is no longer feasible in high-throughput laboratories. When reporting ANA three factors require evaluation: the pattern observed; substrate used and the titre of the positive test. Experienced scientist can interpret ANA slides and distinguish titre levels; however this takes years of experience. The screening dilution is important in patients presenting with positive results, as it helps determine an individuals severity of disease and can prove beneficial to clinicians. Serial dilutions at 1:10, 1:20, 1:40, 1:80, 1:160 and 1:320 can be performed, where the titre value is the one at which positive sample becomes negative. 5% of a healthy population can present with a positive low ANA titre, with no disease activity and are commonly women aged over 60 (Shmerling, 2003). Peterson et al, (2009) found that beside patients with SLE patients, other diseases also present with positive ANA titres. 1:20 healthy people presented with a positive ANA and the number of positives increased to 1:3, with a dilution of 1:40. To reduce the number of fals e positives, titres are commonly performed at 1:80. At LGI titres were performed on all positive samples and pregnant women, regardless of whether they are positive or negative. Pregnant women are closely monitored as a precaution as IgG antibodies cross the placenta, thus anti-Ro/La antigen is capable of causing fetal heart block (Rahman Isenberg, 2008). Patients who presented with symptoms for SLE were also titrated; however lots of weak positive results were seen as a dilution of 1:40 was employed. As workload increased titrations became laborious and impractical, thus performing titres routinely was abolished and titres are now only performed upon request. Cut-offs exist, however these are modified around the local population, to give a better sensitivity (Stinton Fritzler, 2007). Shmerling, (2003) has suggested that ANA titres can correlate with disease activity, but as positive samples undergo antigen specific testing via EIA, titres should be abolished, unless there are specifically requested by the clinicians to monitor changes to disease. Wieser et al, (2001) found that there was a lack of correlation between the clinical features of patients and laboratory results obtained. The study looked at 3 cases with varying antibody titres and established algorithms seen in Figure 1.5. Similarly Hanley et al, (2009) suggested algorithms help in diagnostics (Appendix 2). As a small number of cases were analyses, it appears that there is not sufficient evidence to develop an algorithm; however both the studies have been adapted in Europe as they were seen to prevent patients with detectable antibodies being missed and to avoid the unnecessary testing and time of laboratory staff. Slide processors are available to prepare IIF slides. They first appeared in the late 1990s and include platforms such as ASP1200 and AFT from Binding Site (Figure 1.6). These slide processors ensure that all samples are prepared quickly, reliably and accurately, avoiding cross reactivity in sample preparation. Slide processors perform IIF via indirect antibody reactions as seen in Figure 1.7. Patient serum is incubated with a substrate, followed by washing to remove any unbound protein. A second antibody, FITC is added and this reacts with immunoglobulins which have combined with the substrate. Another washing stage is performed and slides are ready to be mounted and interpreted manually, however this causes subjectiveness. IIF-ANA result interpretation is dependent on the operators setup of the microscope, type and number of hours the bulb (mercury) has been used, type of objective lens, filters and most importantly magnification. At the LGI the Leica DMRB mercury microscope is employed and allows cells to magnify at X200, X400 and X500. Positive results fluoresce an apple-green colour (Table 3), whilst negative samples have little fluorescence. Two independent observers interpret the slides to prevent reading errors and any conflicting results are followed by an anti-ENA and anti-DNA screen. Automated commercial slide readers are now available to allow interpretation of ANAs. Images are automatically scanned and stored within computer systems, where positive and negative ANA results are determined by the amount of flourenscene emitted. The operator can then scan through positive ANAs, identifying their patterns. This aims to improve the subjectiveness seen between scientists and aims to improve accuracy; however these are not robust so not widely used. The advantage of IIF-ANA is that it is easy, inexpensive, available from a wide range of commercial companies, sensitive, reliable and has reduced cross reactivity and background fluorescence. The disadvantages of IIF-ANA are that it is laborious and requires a high degree of technical expertise. Within most Immunology laboratories the ANA test is not linked to the pathology computer systems, so tests cannot be picked up via an interface. This can be problematic as wrong samples can be analysed and reported. The use of barcode readers can overcome this problem. Homogenous Homogenous Pattern is the most common pattern seen in 60% of Systemic Lupus Erythematosus (SLE) patients. However it can be seen in drug induced lupus, Rheumatoid Arthritis. Positive patients are then further evaluated against: Anti-dsDNA, Anti-Smith Speckled Speckled Pattern can exist as coarse expressing is Sm, U1-RNP antigen or fine expressing Ro or La. Sm positive is seen in 4-40% of SLE patients, whilst RNP is seen in high titres in patients with Mixed Connective Tissue Disease (MCTD). Patients with Scleroderma and Sjogrens Syndrome also present with positive results. Centromere Centromere pattern is seen in 57-82% of patients with CREST syndrome and Raynauds. The suspected antigen is CENP A, CENP B, CENP C. Nucleolar Nucleolar Pattern seen in patients with Scleroderma. There are multiple nuclear antigens, such as fibrilliarin. Positive patients are then further tested against Scl-70 (Anti-Topoisomerase I). Table 3: Shows the various ANA patterns seen by IIF on the HEp-2000 substrate (Produced by Nisha Lad, 2010) As different laboratories use different substrates and conjugates, IIF-ANA lacks standardisation worldwide (Bonilla, 2009). A study by Blerk et al, (2008) showed that if laboratories employed the same cells, substrate and conjugate they were able to report the same staining patterns. Over 157 laboratories across Belgium participated and each looked at 9 different samples. Looking at the results it is clear that after considering the variable factors, participants that employed the same HEp-2 slide substrates (Medica, USA) and method of detection were able to produce consistant results, suggesting standardization can be achieved. Although IIF-ANA is subjective, replacement with EIA or bead technology is suggested to increase sensitivity. Bonilla et al (2007) performed a study in the USA suggesting that IIF had a sensitivity of 90.6%, whilst bead technology had a sensitivity of 41.9% and the specificity of IIF was lower at 76%; however for bead technology was 87%. Having tested 385 patients a conclusion was made saying IIF was a better technique for diagnosis of patients with SLE. Olaussen and Rekvig (1999) also produced similar results, where two commercial IIF assays and two commercial ELISA kits consisting of a range of antigens, significant in the diagnosis of SLE were used. The study showed correlation between IIF and ELISA, where sensitivity for IIF was 88%, whilst that for ELISA was 86%. Specificity however varied with 67% for IIF and 60% for ELISA. Another study by Gonzalez et al, (2002), analysed 709 samples comparing IIF and EIA for the diagnosis of ANA. Results showed good reproducibility in both as says, but found that the antibodies which produced a homogenous and speckled IIF patterns were best detected via EIA. On the other hand a study by Nifli et al, (2006) compared routine technology in a selection of Clinical Immunology laboratories and analyzed 11088 samples, using IIF and ELISA at the University Hospital of Heraklion in Greece. Results showed a highly significant correlation for ANA performed by ELISA; however it suggested that as IIF had a low sensitivity of 58%, this could be replaced by multiplex technology, allowing multiple antigen measurement. Looking at these studies closely it appears that although there were similarities between technologies, different kits and manufacturers were used, producing variable results. 1.4.2 Antigen-specific assays for the detection of ANA Many different patterns can be seen by IIF-ANA, however to determine autoantibody specificity further antigen-specific assays are needed. Antibodies against Sm, native dsDNA and chromatin are used in the diagnosis of patients with SLE (Hanley et al, 2009). Currently ANAs are categorised into two main groups; ANA to DNA and histones (dsDNA) and ANA to extractable nuclear antigens (ENA). Enzyme-linked immunosorbent assay (ELISA), also known as an enzyme immunoassay (EIA) are now available for antigen specific testing, providing a new horizon for SLE testing, as they are able to identify individual antigens. ELISA/EIA is the most commonly performed technique, implemented in laboratories today. In the past, ELISA plates were assembled in-house, however as a successful assay requires careful assembly of the different layers, this soon became difficult to achieve, thus commercial ELISA kits were developed in the 1980s to overcome assay failure and to overcome the subjectiveness of IIF-ANA. The ELISA assay can be performed either manually or via automated technologies. 96 well plates coated with the same antigens are commonly used, however Phadia produce an EIA platform, whereby pens containing singles wells with individual antigens can be used, allowing multiple antigen recognition and analysis. Both ELISA/EIA operate via immunometric methods of detection for anti-ENAs and anti-DNAs. The principle (Figure 1.8) of this technique is via microplates which are coated with purified antigens of interest. Patient serum is incubated in the wells and unbound antibody is then washed away, followed by the addition of a conjugate such as alkaline phosphotase (AP) or horseradish peroxidase (HRP). Another wash stage is performed and colorimetric results develop, which are proportional to the initial concentration of antibody in the patients sample. Results are dependant on kit standards, which produce a calibration curve and then the optical density of the wells is taken to give a q uantitative result (Branda et al, 2009). ELISA are a versatile assay, where the amplification of the signal, increases the overall sensitivity of the assay, as it uses an antibody which are specific to the type of antigen/protein being measured. Studies suggest that ELISA is a sensitive assay, however lacks specificity so false positives results are detected (Castro and Gourley, 2009). The advantage of ELISA is that it can be performed both manually and via automation. Analysers can also be linked to the pathology computer systems, preventing transcription errors in result interpretation. However disadvantages for ELISA are that purified antigens need to be prepared via HPLC, meaning assays are not cost effective and can be time-consuming. As microtitre plates are now purchased with one antigen, there is a limited dynamic range of detection; however EIA pens now overcome this problem. To produce successful assays, instrumental conditions need to be carefully considered. Washing errors, contamination of substrate or inadequa te incubation times may produce little signal amplification resulting in false negative results (Castro and Gourley, 2010). 1.4.2.1 Anti-dsDNA Anti-dsDNA were first described in 1957, by Ceppelini and colleagues. Anti-dsDNA are found in patients with SLE and are mainly found in the form of nucleosomes. Nucleosomes are fragments of chromatin that cells release during apoptosis. dsDNA antibodies bind to the nucleosome to form complexes which settle in the glomeruli, resulting in glomerulonephritis and increasing the risk of lupus nephritis flare, thus detection is crucial as it helps to determine the therapy required for treatment. à ¯Ã à ¡-actinin (100kDA) is a microfilament skeletal muscle protein, which aids in maintaining the function of podocytes in the kidney. This protein is not specific for SLE, although it can act as a marker for renal involvement (Raheman et al, 2008). The dsDNA assay can be performed via (Figure 1.9); IIF with Crithidia luciliae substrate (CLIF), Farr assay also known as radioimmunoassay (RIA), however the most commonly used technique is EIA/ELISA as described in 1.4.2. The Farr assay is regarded as the gold standard technique for the detection of dsDNA (Launey et al, 2010). It uses cultured cells labelled with thymidine and idocythidine, which act as radioactive DNA. In the assay bound and free DNA is separated by precipitating immuglobulins and ammonium sulphate. Although this method is good, it misses low avidity anti-DNA antibodies due to a nitrocellular filter, which allows the passage of free DNA and however double stranded DNA (dsDNA) cannot be filtered. Thus the radioactivity is said to be proportional to serum anti-DNA (Isenberg Smeenk, 2002). The Farr assay can detect high affinity antibodies, with relatively high specificity; however it requires precision in pipetting as there must be sufficient labelled DNA to bind to samples in order to reach an endpoint. Although the use of radiolabels within the Farr assay provides highly reproducible results, it becomes very costly, dangerous and difficult to dispose of the radioactive isotopes. Other limitations with this assay are that it only detects IgG and cannot determine any other immunoglobulin isotopes (IgA/IgM), thus patients presenting with dsDNA antibodies to IgA/IgM can be missed (Egner 2000). UK NEQAS shows that the Farr assay is still being used (Figure 1.9), as it is a more accurate confirmatory test that can be used in the diagnosis of SLE. The accuracy of the Farr assay can be seen in many studies. A study by Launey and colleagues (2010) compared the Farr radioimmunoassay to three commercial enzyme immuoassays and CLIF staining. The study looked at 99 patients with SLE and found that the Farr assay was the best assay, offering greater sensitivity and specificity of 95%, than the three other ELIA and CLIF assays. Derksen et al, (2002) also showed similar results. He compared the Fa rr assay with the Varelisa EIA assay and found that the Farr assay was superior to the EIA assay as it presented with a specificity of 95% and a sensitivity of 72%, whilst in EIA specificity corresponded to sensitivities at 44%. Many laboratories also perform follow-up DNA tests by EIA, using CLIF to determine the avidity of anti-dsDNA antibodies. However CLIF can also be used alongside IIF to measure anti-DNA (IIF-DNA) and this does not requiring any specialist equipment, other than a fluorescence microscope. The CLIF assay allows detection of high affinity antibodies through titrations, however this requires precise pipetting. CLIF detects antibodies to kinetoplast of organisms, which consists of circular dsDNA and allows both IgG-anti-dsDNA and IgM-anti-dsDNA to be tested (Gonzalez-Buiterego Gonzalez, 2006). The test is highly reproducible and is particularly suitable for a limited number of samples. Although the assay offers the highest specificity for ANA testing, it has a relatively low diagnostic sensitivity for SLE. Due to the degree of accuracy of the Farr assay, it is undoubtedly the best assay for the detection of dsDNA and so has been approved by the World Health Organisation (WHO) and operates under the WHO80-IRP standard. However due to the risk of handling radioactive substance and the cost of the assay; this is not routinely used within Immunology. 1.4.2.2 Anti-ENA Positive IIF-ANA are typically followed up by extractable nuclear antigens (ENA). ENAs were discovered in 1966 by Smith and colleagues, offering a greater specificity, to allow a more accurate disease diagnosis, in correlation to the initial IIF-ANA screen. Originally ENAs referred to proteins found in a saline extract of cell nuclei, however since then the components have been identified and these consist of cytoplasmic molecules. A whole spectrum of approximately 100 antigens can be screened; however most have no clinical significance. In order to cover the majority of inflammatory autoimmune diseases 6 clinically significant antigens (Table 4); Ro, La, Sm, RNP, Scl-70 and Jo1 are used within most laboratories across the UK. It can be seen that SLE is associated with many of the antigens in the screen. Although ENAs are commonly performed via EIA (Figure 1.10), other methods such as qualitative gel precipitation assays, passive haemagglutination, immunoblotting, counter current immunoelectrophoresis (CIE) and antigen microarray can also be used (Kumar et al, 2009). Sceening of ENAs is expensive in comparison to IIF-ANA as it allows specific antigen detection, offering a greater sensitivity as approximately 90% of positive IIF-ANA produce negative results via EIA (Dahle et al, 2004). Gel precipitation assays such as double immunodiffusion (DID) and counter current immunoelectrophoresis (CIE) are still being used within laboratories; however these were discovered over 5 decades ago. CIE uses an electric current to accelerate the migration of antibody
Wednesday, November 13, 2019
To View or Not To View :: Media News Television Essays
To View or Not To View Staying in touch with the outside world, via the 10:00 evening news, has become increasingly difficult for me the last couple years. Not only am I usually not awake at 10:00, but if I am, I do not want to spend my time hearing about the many murders, rapes, and robberies that plaque our city. Television news has not only taken on a tabloid-like feel, but the substance of most of the news stories is a total waste of my viewing time. However, in an effort to stay connected, I currently listen to the morning TV news as well as read the Chicago Tribune on a daily basis. The local news broadcast I taped to critique for this paper was the 5:00 News on Channel 5 which was shown on Monday, April 7, co-anchored by Joan Esposito, a 30ish white female, and Warren Saunders, a late 50's black male. I viewed a total of 13 stories which were comprised mainly of murder, weather and informational topics. The "Top Story" was about a 7 year old girl who was murdered by a gang member while she was waiting in line to get ice cream. The story's time went for approximately 4 minutes and included 3 interviews of people, 3 different on-screen captions and a camera span of teddy bears on a fence. The actual meaty parts of this story, that is, the facts, were fully given in this broadcast. However, interviews with crying persons of the gang members' families, and the little girl's school superintendent musing out loud on what this little girl could have become, was a total waste of time. Conversely, scanning the teddy bears was touching, but lent nothing to the telling of the tragic event that took this girl's life. I suppose the "powers that be" at the news station do not feel the public can feel on their own, thus we are constantly being given visual reminders of how sad a story is. I can safely say that the Top Story of the majority of broadcasts that I view are murders. Based on that premise, the senseless murder of this child was an important story in Chicago that day. I do take exception, however, to the many visuals used to evoke emotion as the sadness of the story spoke for itself. Apart from this story, the only remaining "news stories" consisted of a murder of a cab driver and two stories of missing persons.
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