Detecting collinear dots in noise

We estimated the sensitivity for detecting a row of collinear target elements (usually dots) by measuring the maximum density of randomly positioned noise elements that allowed 75% correct detection of the orientation of alignment (binary choice: horizontal versus vertical) of the target elements. We varied the number of target elements, their mode of generation, and their accuracy of positioning. As reported previously (Moulden (1994) Higher-order processing in the visual system. Ciba Foundation Symposium 184. Chichester: Wiley), target detection improved rapidly until the number of target elements reached about seven, and then improved more slowly beyond this point. However, this break was reduced (and often removed entirely) when the target array was formed by repositioning pre-existing noise elements lying close to the target location, rather than by superimposition of additional target elements onto the noise array. This almost linear slope of improvement, coupled with the observation that target detection was disrupted more by random jitter of target elements at right angles to their axis of alignment than by jittering along this axis, argues against a two-stage process of perceptual grouping (Moulden, 1994) and supports instead an explanation based on the operation of a single mechanism. This single mechanism explanation is further supported by the observation that intrinsic positional uncertainty (estimated from the results of jitter experiments) was independent of target element number. Additional experiments showed that target detection is facilitated by aperiodic noise dots that fall close to the target axis. The results are discussed in relation to alternative explanations of perceptual grouping.     

Acridine and Its Derivatives: Synthesis,Biological, and Anticorrosion Properties

The phenomenon of corrosion threatens metallic components, human safety, and the economy. Despite being eco-friendly and promising as a corrosion inhibitor, acridine has not been explored to its full potential. In this review, we have discussed multiple biological activities that acridines have been found to show in a bid to prove that they are environmentally benign and much less toxic than many inhibitors. Some synthetic routes to acridines and substituted acridines have also been discussed. Thereafter, a multitude of acridines and substituted acridines as corrosion inhibitors of different metals and alloys in various corrosive media have been highlighted. A short mechanistic insight into how acridine-based compounds function as corrosion inhibitors have also been included. We believe this review will generate an impression that there is still much to learn about previously reported acridines. In the wake of recent surges to find efficient and non-toxic corrosion inhibitors, acridines and their analogs could be an appropriate answer.     

Socioeconomic,demographic study on substance abuse among students of professional college in a southern town,Berhampur of Odisha state (India)

Currently there is an increasing trend of substance abuse in developing countries like India. This study attempted to identify the different predisposing factors, associated psycho-social and medical problems, prevalence and types of substance abuse in students. The study covered a cross-section of 720 students with an overall male to female ratio of 4.1:1. The majority of the sufferers were from middle socioeconomic class, aged between 15 and 19 years. Common substances of abuse were chewable tobacco and cannabis. The risk of abuse was more in hostellers hailing from broken families (62.5%). Friends had the highest influence (59%). Most of them (49.4%) tried multiple times to give up, but peer pressure (53%) compelled them to restart. In 60.8% cases the parents were completely unaware about this behavior. The commonly associated problems were psychological (34.3%) and medical (29.5%).Our study at the end points out major risk factors and their remedial measures to curb substance abuse.     

Using an Ultrasound Elasticity Microscope to Map Three-Dimensional Strain in a Porcine Cornea

An ultrasound elasticity microscope was used to map 3-D strain volume in an ex vivo porcine cornea to illustrate its ability to measure the mechanical properties of this tissue. Mechanical properties of the cornea play an important role in its function and, therefore, also in ophthalmic diseases such as kerataconus and corneal ectasia. The ultrasound elasticity microscope combines a tightly focused high-frequency transducer with confocal scanning to produce high-quality speckle over the entire volume of tissue. This system and the analysis were able to generate volume maps of compressional strain in all three directions for porcine corneal tissue, more information than any previous study has reported. Strain volume maps indicated features of the cornea and mechanical behavior as expected. These results constitute a step toward better understanding of corneal mechanics and better treatment of corneal diseases.     

Acute fatal DDS poisoning. (Report of 4 cases).

Acute dapsone poisoning is rare and such cases are either accidental or suicidal. Though accidental DDS poisoning are reported in children, the same is fairly uncommon in adults. Only 2 such cases are reported in India literature. We here report 4 cases of fatal sucidial DDS poisoning in adults resulting death in 3 cases. The reported acute symptoms include nausea, vomiting, hyperexcitability followed by depression, Carpopedal spasm or convulsions. The most marked signs are dyspnoea and cyanosis. The symptoms are due to methaemoglobinaemia, and or sulphaemoglobinaemia. Normally dapsone induces red cell haemolysis and even with small therapeutic doses of 25-100 mg per day, and in toxic doses reduces the oxygen carrying capacity of blood and damages the red cells making them more vulnerable for haemolysis. The peculiarity of the presentation in this series are manifestation of severe haemorrhagic episode in one case and progressive jaundice in another besides cyanosis. None of the cases had carpopedal spasm or convulsion. Out of four cases three died inspite of intensive care, intravenous vitamin C, exchange transfusion (2 cases) and other supportive measures. Intravenous methylene blue could not be used in these cases due to non-availability.     

Sensitivity and specificity of rapid HIV testing of pregnant women in India

OBJECTIVE: Efforts to prevent HIV transmission from mother to infants in settings like India may benefit from the availability of reliable methods for rapid and simple HIV screening. Data from India on the reliability of rapid HIV test kits are limited and there are no data on the use of rapid HIV tests for screening of pregnant women. METHODS: Pregnant women attending an antenatal clinic and delivery room in Pune agreed to participate in an evaluation of five rapid HIV tests, including (a) a saliva brush test (Oraquick HIV-1/2, Orasure Technologies Inc.), (b) a rapid plasma test (Oraquick HIV-1/2) and (c) three rapid finger prick tests (Oraquick HIV-1/2; HIV-1/2 Determine, Abbott; NEVA HIV-1/2 Cadila). Results of the rapid tests were compared with three commercial plasma enzyme immunoassay (EIA) tests (Innotest HIV AB EIA, Lab systems/ELISCAN HIV AB EIA, UBI HIV Ab EIA). RESULTS: Between September 2000 and October 1, 2001, 1258 pregnant women were screened for HIV using these rapid tests. Forty-four (3.49%) of the specimens were HIV-antibody-positive by at least two plasma EIA tests. All of the rapid HIV tests demonstrated excellent specificity (96-100%). The sensitivity of the rapid tests ranged from 75-94%. The combined sensitivity and specificity of a two-step algorithm for rapid HIV testing was excellent for a number of combinations of the five rapid finger stick tests. CONCLUSION: In this relatively low HIV prevalence population of pregnant women in India, the sensitivity of the rapid HIV tests varied, when compared to a dual EIA algorithm. In general, the specificity of all the rapid tests was excellent, with very few false positive HIV tests. Based upon these data, two different rapid HIV tests for screening pregnant women in India would be highly sensitive, with excellent specificity to reliably prevent inappropriate use of antiretroviral therapy for prevention of vertical HIV transmission.