Versatile stochastic dot product circuits based on nonvolatile memories for high performance neurocomputing and neurooptimization.

The key operation in stochastic neural networks, which have become the state-of-the-art approach for solving problems in machine learning, information theory, and statistics, is a stochastic dot-product. While there have been many demonstrations of dot-product circuits and, separately, of stochastic neurons, the efficient hardware implementation combining both functionalities is still missing. Here we report compact, fast, energy-efficient, and scalable stochastic dot-product circuits based on either passively integrated metal-oxide memristors or embedded floating-gate memories. The circuit's high performance is due to mixed-signal implementation, while the efficient stochastic operation is achieved by utilizing circuit's noise, intrinsic and/or extrinsic to the memory cell array. The dynamic scaling of weights, enabled by analog memory devices, allows for efficient realization of different annealing approaches to improve functionality. The proposed approach is experimentally verified for two representative applications, namely by implementing neural network for solving a four-node graph-partitioning problem, and a Boltzmann machine with 10-input and 8-hidden neurons

High Serum Uric Acid Increases the Risk for Nonalcoholic Fatty Liver Disease: A Prospective Observational Study

Nonalcoholic fatty liver disease (NAFLD) is a common form of chronic liver disease, and serum uric acid is observed to be significantly elevated in NAFLD patients. However, whether this elevation is causal, a bystander, or a consequence of NAFLD remains unclear. We performed a population-based prospective study among the employees of Zhenhai Refining & Chemical Company Ltd., Ningbo, China to investigate whether the elevation of serum uric acid has a casual role for NAFLD. A total of 6890 initially NAFLD-free subjects were followed up for 3 years. Overall, 11.80% (813/6890) subjects developed NAFLD over 3 years of follow-up. The cumulative incidence of NAFLD increased with progressively higher baseline serum uric acid levels (the cumulative incidence was 7.2%, 9.5%, 11.5%, 13.8%, and 17.2% in quintile 1, quintile 2, 3, 4 and 5, respectively; P value for trend <0.001). Cox proportional hazards regression analyses showed that serum uric acid levels were independently and positively associated with the risk for incident NAFLD; the age-, gender- and metabolic syndrome adjusted hazard ratio (95% CI) for the subjects in quintile 2, 3, 4 and 5 versus quintile 1 was 1.18 (0.91–1.54), 1.32 (1.03–1.70), 1.39 (1.09–1.78) and 1.50 (1.18–1.92), respectively. Taken together, our prospective observational study showed that elevation of serum uric acid levels independently predicts increase risk for incident NAFLD

Metabolic and endocrinologic complications in beta-thalassemia major: a multicenter study in Tehran

BACKGROUND: The combination of transfusion and chelation therapy has dramatically extended the life expectancy of thalassemic patients. The main objective of this study is to determine the prevalence of prominent thalassemia complications. METHODS: Two hundred twenty patients entered the study. Physicians collected demographic and anthropometric data and the history of therapies as well as menstrual histories. Patients have been examined to determine their pubertal status. Serum levels of 25(OH) D, calcium, phosphate, iPTH were measured. Thyroid function was assessed by T3, T4 and TSH. Zinc and copper in serum were determined by flame atomic absorption spectrophotometry. Bone mineral density (BMD) measurements at lumbar and femoral regions have been done using dual x-ray absorptiometry. The dietary calcium, zinc and copper intakes were estimated by food-frequency questionnaires. RESULTS: Short stature was seen in 39.3% of our patients. Hypogonadism was seen in 22.9% of boys and 12.2% of girls. Hypoparathyroidism and primary hypothyroidism was present in 7.6% and 7.7% of the patients. About 13 % of patients had more than one endocrine complication with mean serum ferritin of 1678 ± 955 micrograms/lit. Prevalence of lumbar osteoporosis and osteopenia were 50.7% and 39.4%. Femoral osteoporosis and osteopenia were present in 10.8% and 36.9% of the patients. Lumbar BMD abnormalities were associated with duration of chelation therapy. Low serum zinc and copper was observed in 79.6% and 68% of the study population respectively. Serum zinc showed significant association with lumbar but not femoral BMD. In 37.2% of patients serum levels of 25(OH) D below 23 nmol/l were detected. CONCLUSION: High prevalence of complications among our thalassemics signifies the importance of more detailed studies along with therapeutic interventions

Listeria monocytogenes in Milk Products

peer-reviewedMilk and milk products are frequently identified as vectors for transmission of Listeria monocytogenes. Milk can be contaminated at farm level either by indirect external contamination from the farm environment or less frequently by direct contamination of the milk from infection in the animal. Pasteurisation of milk will kill L. monocytogenes, but post-pasteurisation contamination, consumption of unpasteurised milk and manufacture of unpasteurised milk products can lead to milk being the cause of outbreaks of listeriosis. Therefore, there is a concern that L. monocytogenes in milk could lead to a public health risk. To protect against this risk, there is a need for awareness surrounding the issues, hygienic practices to reduce the risk and adequate sampling and analysis to verify that the risk is controlled. This review will highlight the issues surrounding L. monocytogenes in milk and milk products, including possible control measures. It will therefore create awareness about L. monocytogenes, contributing to protection of public health

A Study on the Immunity Level of 5-25 Years Old Population of Baft and Kahnooj Districts (Kerman, Iran) before and after M.R. Vaccination Mass Campaign in 2003

Abstract: Introduction: Measles Involves 45 millions and Kills 1.1 Millions in the World Annually. In Iran before mass campaign, the incidence rate of measles had increased dramatically. This study was done on 5-25 years old individuals in Baft and Kahnooj districts in order to compare their Immunity level, against measles, after and before the national mass campaign for M.R. vaccination (2003). Method: In this study, blood sampling was done twice. The first four weeks before and the other four weeks after mass campaign. Total number of cases were 1089, of whom 552 cases before and 537 cases after mass campaign were tested by E.nzygnost-Anti Measles Virus IgG Kit. In addition, demographic data such as sex, age, place of residency and history of vaccination were collected through a questionnaire. Results: According to the results mass campaign vaccination was considerably effective and increased seropositive cases from 42.6 percent to 100%. Before mass campaign, the level of seropositive cases among four age groups of 5-9, 10-14, 15-19 and 20-25 years were 46%,46%,41.7%, and 34.1% respectively. In regard to sex, before mass campaign, 46.4 % of males and 34.3% of females had seropositive responses. In Baft district 54.5% and in Kahnooj district 31.3% were seropositive. In urban areas 47.1 % and in rural areas 32.6% of cases had seropositive responses. All mentioned rates, increased to 100% after Mass campaign. Conclusion: According to the results, before MR. mass compaign immunity had reverse relation with age and M.R. mass campaign was significantly effective in rising the immunity to a favorite level (from 42.6% to 100%). Keywords: Measleas-antibady, Seroepidemology, Mass campign, Herd immunit

Experimental study to evaluate the pretreatment of Melissa Officinalis extract against lethal seizures induced by Pentylentetrazole in Wistar rats

Abstract: Melissa officinalis is a well known medicinal plant. Different studies performed in mice have shown the sedative, hypnotic, analgesic, antiviral and antimicrobial effects of this plant. The present investigation was undertaken to evaluate the effect of percolated extract of this plant against lethal seizure induced by intraperitonal injection of pentylenetetrazole (PTZ) in wistar rats. The study was performed on three groups of animals pretreated with different doses of extract via intraperitonal injection. After 30 minutes each animal received high dose of PTZ (90 mg/kg) for induction of lethal seizure. The control group received normal saline. In addition a positive control group pretreated with diazepam, a well known drug in the treatment of seizure, was used for comparison. The efficacy of the extract to protect the animals against lethal seizure was based on the latency of the appearance of the first sign of seizure or the latency of the different epileptic manifestations and decrease of mortality rate in each group. The results showed that various epileptic manifestations are delayed in diazepam pretreated animals and extract compared with control group. The dose of 50 mg/kg of the extract appeared to be significantly effective on the tremors and the myoclonic jerks of epileptic manifestations (P<0.05). In addition the mortality rate was significantly reduced in pretreated animals with this dose compared with control group (P<0.05). Mortality rate was 88% in saline group, 13% in 50mg group and zero percent in diazepam group. The results indicated that the extract of Melissa officinalis possesses anticonvulsant property. Keywords: Melissa officinalis, Seizure, Pentylentetrazole, Anticonvulsant activity, Ra

Comparison of conventional risk factors in middle-aged versus elderly diabetic and nondiabetic patients with myocardial infarction: prediction with decision-analytic model

BACKGROUND: We sought to predict occurrence of myocardial infarction (MI) by means of a classification and regression tree (CART) model by conventional risk factors in middle-aged versus elderly (age ⩾65years) diabetic and nondiabetic patients from the Modares Heart Study. METHOD: A total of 469 patients were randomly selected and categorized into two groups according to clinical diabetes status. Group I consisted of 238 diabetic patients and group II consisted of 231 nondiabetic patients. Our population was MI positive. The outcome investigated was diabetes mellitus. We used a decision-analytic model to predict the diagnosis of patients with suspected MI. RESULTS: We constructed 4 predictive patterns using 12 input variables and 1 output variable in terms of their sensitivity, specificity and risk. The differences among patterns were due to inclusion of predictor variables. The CART model suggested different variables of hypertension, mean cell volume, fasting blood sugar, cholesterol, triglyceride and uric acid concentration based on middle-aged and elderly patients at high risk for MI. Levels of biochemical measurements identified as best risk cutoff points. In evaluating the precision of different patterns, sensitivity and specificity were 47.9-84.0% and 56.3-93.0%, respectively. CONCLUSIONS: The CART model is capable of symbolizing interpretable clinical data for confirming and better prediction of MI occurrence in clinic or in hospital. Therefore, predictor variables in pattern could affect the outcome based on age group variable. Hyperglycemia, hypertension, hyperlipidemia and hyperuricemia were serious predictors for occurrence of MI in diabetics

4K-memristor analog-grade passive crossbar circuit.

The superior density of passive analog-grade memristive crossbar circuits enables storing large neural network models directly on specialized neuromorphic chips to avoid costly off-chip communication. To ensure efficient use of such circuits in neuromorphic systems, memristor variations must be substantially lower than those of active memory devices. Here we report a 64 × 64 passive crossbar circuit with ~99% functional nonvolatile metal-oxide memristors. The fabrication technology is based on a foundry-compatible process with etch-down patterning and a low-temperature budget. The achieved &lt;26% coefficient of variance in memristor switching voltages is sufficient for programming a 4K-pixel gray-scale pattern with a &lt;4% relative tuning error on average. Analog properties are also successfully verified via experimental demonstration of a 64 × 10 vector-by-matrix multiplication with an average 1% relative conductance import accuracy to model the MNIST image classification by ex-situ trained single-layer perceptron, and modeling of a large-scale multilayer perceptron classifier based on more advanced conductance tuning algorithm