Highly sensitive p-type 4H-SiC van der Pauw sensor

This paper presents for the first time a p-type 4H silicon carbide (4H-SiC) van der Pauw strain sensor by utilizing the strain induced effect in four-terminal devices. The sensor was fabricated from a 4H-SiC (0001) wafer, using a 1 μm thick p-type epilayer with a concentration of 10¹⁸ cm⁻³. Taking advantage of the four-terminal configuration, the sensor can eliminate the need for resistance-to-voltage conversion which is typically required for two-terminal devices. The van der Pauw sensor also exhibits an excellent repeatability and linearity with a significantly large output voltage in induced strain ranging from 0 to 334 ppm. Various sensors aligned in different orientations were measured and a high sensitivity of 26.3 ppm⁻¹ was obtained. Combining these performances with the excellent mechanical strength, electrical conductivity, thermal stability, and chemical inertness of 4H-SiC, the proposed sensor is promising for strain monitoring in harsh environments.

This paper presents for the first time a p-type 4H silicon carbide (4H-SiC) van der Pauw strain sensor by utilizing the strain induced effect in four-terminal devices.     

Enhanced platelet aggregation, high homocysteine level, and microvascular disease in diabetic muscle infarctions: implications for therapy

Muscle infaction is a rare complication in patients with diabetes mellitus, probably because of the rich vascular supply of this tissue. We describe a patient with type 1 diabetes who had infarction of the muscles in her right thigh. We report, for the first time, that the patient, in addition to an advanced microvascular disease in the muscle, had increased plasma total homocysteine levels and increased platelet aggregation. These pathologies might have a synergistic effect on the development of this rare complication and should be treated aggrssively to prevent further episodes.     

Coronary artery disease is associated with the ratio of apolipoprotein A-I/B and serum concentration of apolipoprotein B, but not with paraoxonase enzyme activity in Iranian subjects

To determine the association of serum apolipoprotein (apo) A-I and B concentrations, and paraoxonase (PON) high-density lipoprotein (HDL) associated enzyme activity with angiographically determined coronary artery disease (CAD) in Iranian diabetic and non-diabetic CAD patients and non-diabetic control subjects, 251 subjects aged 30-70 years, who underwent their first coronary angiography were matched and randomly assigned into three groups: CAD(+)DM(+), CAD(+)DM(-), and CAD(-)DM(-) (control). Stenosis of > or =50% in one or more coronary arteries was classified as CAD(+). CAD(-) was defined as a maximum stenosis of 10% in any coronary artery. Fasting serum concentrations of cholesterol (TC), triglycerides (TGs), LDL-C, HDL-C, apo A-I/B and PON activity were determined. Apolipoprotein concentrations were measured in a fasting serum sample by immunoturbidometric assay and paraoxonase/arylesterase activities by spectrophotometric assay of p-nitrophenol/phenol production following addition of paraoxon/phenylacetate. Information concerning non-lipid risk factors were collected by questionnaires. No significant difference was observed in HDL-C, LDL-C, apo A-I, and PON/arylesterase activity between the study groups. The values of TC (213+/-38 vs 196+/-45, P<0.05), TGs (209+/-187 vs 151+/-113, P<0.01), apo B (99+/-22 vs 96+/-24, P<0.0001), TC/HDL-C (4.8+/-1.5 vs 4.0+/-1.3, P<0.001) and LDL-C/HDL-C (2.9+/-1.1 vs 2.4+/-1.1, P<0.05) were higher and apo A-I/B (1.7+/-0.4 vs 2.0+/-0.6, P<0.01) was lower in CAD(+)DM(+) patients than in control subjects. In CAD(+)DM(-) group, only the level of apo B (96+/-24 vs 85+/-18, P<0.01), and the ratio of apo A-I/B (1.8+/-0.4 vs 2.0+/-0.6, P<0.01), were significantly higher than those of control group. On multiple logistic regression analysis, the best markers for discrimination between CAD(+) groups and CAD(-) control subjects were the ratio of apo A-I/B in diabetic and apo B in non-diabetic patients. The results suggest that in Iranian diabetic and non-diabetic patients with CAD the concentration of apolipoproteins are better markers than traditional lipid parameters in discriminating between CAD(+) and CAD(-) subjects. Lack of significant difference in PON activity between CAD patients and CAD(-) controls supports the concept of interethnic variability in PON polymorphism and unimodal distribution of its activity in non-Europid populations observed in other studies.     

Genetic Characterization of Echinococcus granulosus from a Large Number of Formalin-Fixed,Paraffin-Embedded Tissue Samples of Human Isolates in Iran

Cystic echinococcosis (CE), caused by the larval stage of Echinococcus granulosus, presents an important medical and veterinary problem globally, including that in Iran. Different genotypes of E. granulosus have been reported from human isolates worldwide. This study identifies the genotype of the parasite responsible for human hydatidosis in three provinces of Iran using formalin-fixed paraffin-embedded tissue samples. In this study, 200 formalin-fixed paraffin-embedded tissue samples from human CE cases were collected from Alborz, Tehran, and Kerman provinces. Polymerase chain reaction amplification and sequencing of the partial mitochondrial cytochrome c oxidase subunit 1 gene were performed for genetic characterization of the samples. Phylogenetic analysis of the isolates from this study and reference sequences of different genotypes was done using a maximum likelihood method. In total, 54.4%, 0.8%, 1%, and 40.8% of the samples were identified as the G1, G2, G3, and G6 genotypes, respectively. The findings of the current study confirm the G1 genotype (sheep strain) to be the most prevalent genotype involved in human CE cases in Iran and indicates the high prevalence of the G6 genotype with a high infectivity for humans. Furthermore, this study illustrates the first documented human CE case in Iran infected with the G2 genotype.