Graphene overcoats for ultra-high storage density magnetic media.

Hard disk drives (HDDs) are used as secondary storage in digital electronic devices owing to low cost and large data storage capacity. Due to the exponentially increasing amount of data, there is a need to increase areal storage densities beyond ~1 Tb/in2. This requires the thickness of carbon overcoats (COCs) to be <2 nm. However, friction, wear, corrosion, and thermal stability are critical concerns below 2 nm, limiting current technology, and restricting COC integration with heat assisted magnetic recording technology (HAMR). Here we show that graphene-based overcoats can overcome all these limitations, and achieve two-fold reduction in friction and provide better corrosion and wear resistance than state-of-the-art COCs, while withstanding HAMR conditions. Thus, we expect that graphene overcoats may enable the development of 4-10 Tb/in2 areal density HDDs when employing suitable recording technologies, such as HAMR and HAMR+bit patterned media.

Potential of graphene-based materials to combat COVID-19: properties, perspectives, and prospects.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a new virus in the coronavirus family that causes coronavirus disease (COVID-19), emerges as a big threat to the human race. To date, there is no medicine and vaccine available for COVID-19 treatment. While the development of medicines and vaccines are essentially and urgently required, what is also extremely important is the repurposing of smart materials to design effective systems for combating COVID-19. Graphene and graphene-related materials (GRMs) exhibit extraordinary physicochemical, electrical, optical, antiviral, antimicrobial, and other fascinating properties that warrant them as potential candidates for designing and development of high-performance components and devices required for COVID-19 pandemic and other futuristic calamities. In this article, we discuss the potential of graphene and GRMs for healthcare applications and how they may contribute to fighting against COVID-19.

Vitamin D levels and microvascular complications in type 2 diabetes.

BACKGROUND: Vitamin D has important actions on glucose metabolism. These include improved insulin exocytosis, direct stimulation of insulin receptor, improved uptake of glucose by peripheral tissues, improving insulin resistance. It has got various pleiotropic effects like suppression of cell mediated immunity, regulation of cell proliferation, stimulation of neurotropic factors such as nerve growth factor, Glial cell line-derived neurotrophic factor, neurotropin, suppression of RAAS, reduction of albuminuria, immunomodulatory effects, and anti-inflammatory effects. Thus, vitamin D is implicated in many ways in the pathogenesis of retinopathy, neuropathy and nephropathy. OBJECTIVES: To study the correlation of vitamin D levels with microvascular complications in type 2 diabetes. MATERIALS AND METHODS: Cross-sectional case-control study of 18 patients (18-70 years), who met the American Diabetes Association 2011 criteria for type 2 diabetes, was conducted. Age and sex matched healthy controls were taken. Subjects were evaluated for the presence of microvascular complications by clinical evaluation, urine examination, fundus examination, nerve conduction studies, and various biochemical tests. 25-OH cholecalciferol levels were done for each. Cut off level for vitamin D deficiency was 20 ng/ml. RESULTS: Mean vitamin D was lower in type 2 diabetics than healthy subjects (19.046 vs. 27.186 ng/ml). Prevalence of vitamin D deficiency and insufficiency was found to significantly higher in diabetics when compared to healthy subjects (P = 0.0001). Vitamin D deficiency was found to be significantly associated with neuropathy (χ(2) = 5.39, df = 1, P = 0.020), retinopathy, (χ(2) = 6.6, df = 1, P = 0.010) and nephropathy (χ(2) = 10. 52, df = 1, P = 0.001). Lower levels of vitamin D were found to be associated with increasing prevalence of combinations of microvascular complications namely neuropathy with retinopathy (P = 0.036), neuropathy with nephropathy (P = 0.029), retinopathy with nephropathy (P = 0.022) and neuropathy with retinopathy with nephropathy (P = 0.0001).

Histogenesis of salivary gland neoplasms.

Salivary gland tumors are one of the most complex and relatively rare group of lesions encountered in oral pathology practice. Their complexity is attributed to heterogeneity of the cells of origin of these lesions. The problem is compounded by the ability of these cells to differentiate and modify into various morphological subtypes resulting in a myraid of histomorphological patterns. This also leads to a frequent overlap of microscopic features among various neoplasms and sometimes even between benign and malignant lesions causing significant diagnostic dilemma which sometimes may even not be resolved by immunohistochemical studies. Despite this the knowledge of histogenesis and morhogenetic concepts of salivary gland tumorigenesis greatly helps the pathologist in classifying these lesions as well as determining the prognosis. It will also help in development of newer strategies for differentiating these lesions and making an early diagnosis. The present article is aimed at reviewing and summarizing the current concepts regarding the histogenesis of salivary gland tumors and their relevance to routine diagnosis and classification of these lesions.

Study on the response of diploid, tetraploid and hexaploid species of wheat to the elevated CO2.

Study was done to compare the response of Triticum aestivum (hexaploid), Triticum durum (tetraploid) and Triticum monococcum (diploid) wheat species to the elevated CO2 using Free Air CO2 Enrichment (FACE) facility. It was demonstrated that the modern cultivar of wheat Triticum aestivum (hexaploid) was largely sink limited. It appeared to have less photosynthesis per unit leaf area than Triticum monococcum (diploid wheat). While leaf size, grain weight and amylase activity increased with the ploidy level from diploid to hexaploid wheat forms, the photosynthetic rate was reduced significantly. These wheat species responded differentially to the elevated CO2. The larger leaf area and greater seed weight and presence of 38 KDa protein band caused by elevated CO2 had additive effect in improving the productivity of hexaploid wheat by changing the source sink ratio. Whereas, such a source sink balance was not induced by elevated CO2 in diploid wheat. The increasing CO2 may present opportunities to breeders and possibly allow them to select for cultivars responsive to the elevated CO2 with better sink potential.

Accidental isoniazid poisoning--a report.

Eight patients who had taken accidental overdose of Isoniazid were followed in relation to its clinical manifestations, EEG changes and management. All cases survived without any residual effect.

Neuromuscular respiratory failure in Guillain-Barre Syndrome: evaluation of clinical and electrodiagnostic predictors.

UNLABELLED: Guillain-Barre Syndrome (GBS) has an unpredictable clinical course with up to 30% of patients requiring assisted ventilation during the course of their illness. Successful management mandates anticipation, prompt recognition and optimal treatment of neuromuscular respiratory failure in GBS. AIMS: To identify clinical and electrodiagnostic predictors of neuromuscular respiratory paralysis in GBS. MATERIALS AND METHODS: Forty six patients of GBS were studied over a 6 year period, the study being 2 year retrospective and 4 year prospective. Clinical and electrodiagnostic data were compared between ventilated (28) and non-ventilated (18) patients. The clinical parameters assessed were median age, gender, antecedent infection, prior lung disease, time to peak disability, bifacial weakness, upper limb weakness, bulbar paralysis, neck weakness and autonomic dysfunction. Electrodiagnostic studies included motor nerve conduction studies in 11 ventilated and 13 non-ventilated patients, done prior to maximum disability in each group. Multiple logistic regression analysis was used to compare the two groups. RESULTS: Comparing the clinical data in the ventilated and non-ventilated groups, 'early peak disability', autonomic dysfunction and bulbar weakness predicted the onset of respiratory paralysis. Age, gender, neck or bifacial weakness, upper limb paralysis, or preceding infection did not influence the development of neuromuscular respiratory weakness. Electrodiagnostic testing revealed abnormal H reflex and F waves to be the commonest abnormality in either group. Although data was not sufficient for statistical analysis, the presence of markedly attenuated Compound Muscle Action Potentials inexcitable motor nerves and denervation changes on the electromyography, was commoner in the ventilated group. Thirty six patients received treatment with either plasmapheresis (12) or intravenous immunoglobulin (24). Overall mortality was 5, all 5 patients being on assisted ventilation. CONCLUSION: Early progression to peak disability, bulbar dysfunction and autonomic instability predicted the development of neuromuscular respiratory paralysis in GBS. Early electrodiagnostic studies in this series suggest axonopathic GBS as a predictor of respiratory paralysis, a finding that needs to be evaluated with sufficient data to permit statistical analysis.

Current status of malaria control.

Malaria caused by Plasmodium parasites kills approximately 1-3 million people and causes disease in 300-500 million people annually throughout the world. The current approaches to curtail this disease include vector control, vaccination, immunotherapy and chemotherapy. The vector control is achieved by reducing vector density, interrupting their life cycle, and creating a barrier between the human host and mosquitoes. A number of vaccine candidates are being clinically tried and R&D effort in this direction is coming in a big way. Currently there are only limited safe drugs for the treatment of this disease, however, reports of emerging resistance against existing drugs warrant the introduction of new drugs, which are unlikely to come from pharmaceutical industries because of limited commercial opportunities. One of the most important current approaches to develop new drugs involves the synthesis of chemical libraries and evaluate them against most validated biochemical targets of malarial parasite. Although a number of such targets in antimalarial drug development are known today, yet only validated and selective biochemical targets including mitochondrial transport, glycolic pathway, folate pathway, proteases and heme metabolism, apicoplast metabolism, glycophospatidyl inositol, lipid metabolism (glycerophospholipids), peptidyl deformylase and oxidative stress in parasite-infected erythrocytes have been discussed here. The well known antimalarial drugs and different drug combinations for the treatment of malaria are also briefly reviewed. A survey of the recently discovered new molecules active against malaria has also been narrated. Lastly, the future of malaria chemotherapy and new directions emerging from literature has been elucidated.

Role of biological antioxidants in benzanthrone toxicity.

Previous studies indicate that benzanthrone, an anthraquinone dye intermediate, caused significant depletion of ascorbic acid (AsA). In this investigation the effect of benzanthrone on the status of different forms of AsA and other bio-antioxidants such as glutathione (GSH) was studied. Oral administration of benzanthrone (50, 125 or 250 mg/kg body weight) resulted in a significant increase of urinary AsA levels with a concomitant decrease in the urinary dehydroascorbic acid (DHA) content in both rats and guinea-pigs. Benzanthrone caused a dose-dependent decrease in hepatic, adrenal and serum AsA levels with a subsequent increase in DHA and diketogulonic acid (DKA) levels in both rats and guinea-pigs. Following benzanthrone treatment, rats showed an increase in the scorbutic index (to 1.01-1.21) of the liver, adrenal glands and serum compared to controls (0.12-0.24). The scorbutic indices of liver, adrenal glands and serum were also substantially increased (to 3.61-11.20) in benzanthrone-treated guinea-pigs compared to controls (0.16-0.38). Single oral administration of benzanthrone to guinea-pigs caused a dose-dependent depletion of GSH in liver (15-51%), adrenal glands (27-64%) and serum (32-86%). Furthermore, the depletion of GSH by benzanthrone in rats was of a lesser degree. This suggests that continued exposure of guinea-pigs to benzanthrone may lead to scurvy-type changes in this animal species but not to the same extent in rats, since the latter has the enzymatic capacity to synthesise AsA. Therefore, it can be hypothesised that benzanthrone per se, or its metabolites, interact with reduced GSH thereby causing its depletion. Furthermore, in order to replenish the depleted GSH levels, AsA might be oxidized to DHA and hence the decrease in AsA with the simultaneous increase in DHA was observed.

Ethylbenzene induces microsomal oxygen free radical generation: antibody-directed characterization of the responsible cytochrome P450 enzymes.

Small aromatic hydrocarbons cause changes in oxidative metabolism by modulating the levels of cytochrome P450 enzymes, with the changes in these enzymes being responsible for qualitative changes in aromatic hydrocarbon metabolism. The goal of this study was to determine if exposure to the small alkylbenzene ethylbenzene (EB) leads to an increase in hepatic free radical production. Male F344 rats were treated with ip injections of EB (10 mmol/kg) and compared to corn oil controls. Hepatic free radical production was examined by measuring the conversion of 2',7'-dichlorofluorescin diacetate (DCFH-DA) to its fluorescent product 2',7'-dichlorofluorescein (DCF). A significant elevation of fluorescent DCF production was observed after treatment with EB, despite the lack of effect on overall cytochrome P450 levels. This process was shown to be inhibitable by metyrapone, an inhibitor of P450. DCF production was also inhibited by catalase, suggesting that hydrogen peroxide (H(2)O(2)) is one of the reactive oxygen intermediates involved in EB-mediated reactive oxygen species (ROS) formation. Interestingly, superoxide dismutase (SOD) did not inhibit DCF production in corn oil-treated rats but was an effective inhibitor in the EB-treated groups. In an effort to determine if the increase in ROS production was related to changes in specific P450 enzymes, DCF production was measured in the presence of anti-CYP2B, anti-CYP2C11, anti-CYP2E1, and anti-CYP3A2 inhibitory antibodies. Anti-CYP2B antibodies inhibited DCF production in EB-treated, but not corn oil groups, which is consistent with the low constitutive levels of this enzyme and its induction by EB. The data also demonstrate that CYP2B contributes to ROS production. Anti-CYP2C11 did not influence DCF production in either group. ROS formation in corn oil-treated rats as well as in ethylbenzene-treated rats was also inhibited with antibodies to anti-CYP2E1 and anti-CYP3A2. These results suggest that CYP2C11 does not appear to influence free radical production and that the increase in free radical production in EB treated rats is consistent with the EB-mediated elevation of CYP2B, CYP 2E1, and CYP3A2. Such alterations in free radical generation in response to hydrocarbon treatment may contribute to the toxicity of these compounds.

Thrombosis of a mechanical tricuspid valve prosthesis and of the left subclavian vein: successful therapy with thrombolysis.

A patient with thrombosis of a mechanical prosthetic valve in the tricuspid position, simultaneous extensive left subclavian vein thrombotic occlusion, and pulmonary embolism is successfully treated with a urokinase infusion delivered using catheter-based techniques.

Myocarditis and hemiplegia from scorpion bite--a case report.

A 16 year old boy presenting with features of myocarditis and pulmonary oedema following scorpion sting developed hemiplegia with patchy vasculitic lesions on CT scan. The possible pathogenic mechanism is discussed.

Visual evoked responses in ethambutol induced optic neuritis.

Pattern evoked responses were recorded in 46 patients of tuberculosis on ethambutol and 16 healthy subjects. Deterioration in visual acuity was documented in two patients (4.3%). P100 latency was delayed in 16 cases (34.8%), while in 12 patients (26.1%) both latency and amplitude were affected. A cut off latency value of > or = 140 ms was associated with ophthalmological findings. The incidence of subclinical toxicity as detected by visual evoked response (VER) was higher in older subjects, patients on higher doses of ethambutol (> or = 20 mg/kg/day) and longer duration of treatment. Of two cases with objective ocular signs, one who reported for follow up after two months had recovered completely after stopping ethambutol. Recording of VER is an extremely useful objective test for subclinical optic nerve damage.

Serum and blister fluid cytokines and complement proteins in a patient with Henoch Schönlein purpura associated with a bullous skin rash.

A case is presented of an adult with Henoch Schonlein purpura (HSP) with widespread bullous skin lesions in whom serum and bullous fluid (BF) cytokines and complement proteins were analysed. In both serum and BF the total haemolytic complement was subnormal. Soluble CD25 (sCD25), which is important in B cell activation and proliferation, was over 13 times higher in the BF compared with serum. The serum and BF levels of interleukin (IL) 1, IL6, IL10, tumour necrosis factor alpha and interferon gamma were within the normal serum range of 30 healthy control subjects simultaneously analysed. The raised levels of sCD23 in BF suggest dysregulated humoral immunity in the cutaneous lesions of HSP.

Modulation by ascorbic acid of the cutaneous and hepatic biochemical effects induced by topically applied benzanthrone in mice.

Modulation of biochemical markers by ascorbic acid was investigated in mice to which benzanthrone (BA) was applied topically (150 nmol/mouse) twice a week for 34 wk. After BA exposure without ascorbic acid, in the skin there were significant decreases in the activities of aryl hydrocarbon hydroxylase (AHH; 38% decrease relative to controls) and ethoxyresorufin-O-deethylase (EROD; 39%), and enhancement of the activities of quinone reductase (41% increase), tyrosinase (82%) and histidine decarboxylase (HDC; 190%). BA exposure also caused significant inhibition of hepatic AHH, EROD and glutathione-S-transferase activities, with concomitant increases in the activities of histidase (52%) and HDC (58%). Ascorbic acid given orally (5 mg/mouse) or topically (1 mg/mouse) twice weekly for 34 wk to BA-treated mice resulted in substantial protection against the effects of BA on these enzyme markers in both the skin and the liver. These results suggest that ascorbic acid could be useful in preventing the biochemical and toxicological manifestations caused by BA in laboratory animals.

Isoniazid induced neuropathy in slow versus rapid acetylators: an electrophysiological study.

Clinical, biochemical and nerve conduction studies were performed in 100 cases of tuberculosis taking isonicotinic acid hydrozide (isoniazid) for more than 12 weeks. Electro-physiological studies were carried out in a similar number of normal age and sex matched controls. In 16 percent of cases an abnormality was documented in the motor nerve conduction velocity, amplitude and terminal latency of the common peroneal, ulnar and median nerves; of these, only two patients had objective evidence of neuritis. The occurrence of isoniazid neuropathy was found to be more in the fourth decade of life (10 of 16), in those who had taken the drug for over six months (13 of 16), and in 'slow' inactivators (10 of 16).

Contrast computed tomography in epilepsy with special reference to intracranial ring or disc enhancing lesions.

We report the results of computed tomography (CT) in 170 patients who developed seizures. Localized signs could be demonstrated by neurologic examination in 23.5%. CT findings were normal in 64 patients (37.6%). The commonest abnormality was a focal ring or disc enhancing lesion in 66 patients (62.3%) followed by calcification (18 patients; 16.9%), cerebral atrophy (9; 8.5%), vascular lesions (7; 6.6%), tumours (4; 3.8%) and congenital hydrocephalus (2; 1.9%). The occurrence of abnormal CT was higher (74.3%) in patients with partial seizures.