Photoconductivity of PbTe:In films with variable microstructure

It is shown that the microstructure and features of formation of surface states in nanocrystalline and polycrystalline PbTe:In films most significantly affect the character of photoconductivity in the spectral range of 1–2.5 THz. We present the results of a study and comparative analysis of the character of conductivity of PbTe:In films in the temperature range from 4.2 to 300 K in a static mode and in variable electric fields with a frequency of up to 1 MHz with illumination with white light and under the effect of high-power terahertz laser pulses with a wavelength of up to 280 μm.     

Stabilization and Encapsulation of Gold Nanostars Mediated by Dithiols

Surface chemistry plays a pivotal role in regulating the morphology of nanoparticles, maintaining colloidal stability, and mediating the interaction with target analytes toward practical applications such as surface‐enhanced Raman scattering (SERS)‐based sensing and imaging. The use of a binary ligand mixture composed of 1,4‐benzenedithiol (BDT) and hexadecyltrimethylammonium chloride (CTAC) to provide gold nanostars with long‐term stability is reported. This is despite BDT being a bifunctional ligand, which usually leads to bridging and loss of colloidal stability. It is found however that neither BDT nor CTAC alone are able to provide sufficient colloidal and chemical stability. BDT‐coated Au nanostars are additionally used as seeds to direct the encapsulation with a gold outer shell, leading to the formation of unusual nanostructures including semishell‐coated gold nanostars, which are characterized by high‐resolution electron microscopy and electron tomography. Finally, BDT is exploited as a probe to reveal the enhanced local electric fields in the different nanostructures, showing that the semishell configuration provides significantly high SERS signals as compared to other core–shell configurations obtained during seeded growth, including full shells.     

Inhalation of nitric oxide: effect on cerebral hemodynamics and activity, and antioxidant status in the newborn lamb

Ventilation with nitric oxide (NO) is increasingly being used to treat pulmonary hypertension in the newborn. In the brain, NO has vasoactive properties and is involved in neurotransmission. However, the effect of inhaled NO on the cerebral blood flow (CBF) and on the cerebral activity is not known. Furthermore, there is little information on the influence of this free radical gas on the redox status in pulmonary vessels. We therefore investigated the effect of inhaled NO (2-60 ppm) on CBF, cerebral activity and redox status in blood effluent from the pulmonary circulation in 6 ventilated newborn lambs before and during group B streptococci (GBS)-induced pulmonary hypertension. Blood pressure in the pulmonary artery (P(ap)) and aorta (Pao), carotid artery blood flow (Qcar) to assess changes in CBF, and electrocortical activity were measured. Blood gases, indices of free radical status and methemoglobin were determined in blood samples obtained from the left ventricle. Inhalation of NO, before and during GBS-induced pulmonary hypertension, decreased P(ap) and PCO2 and increased PO2. Multiple linear regression revealed that Qcar was positively related to PCO2, but not to inhaled NO or PO2 before or during GBS conditions. Electrocortical activity and indices of antioxidative capacity and lipid peroxidation did not change significantly. Methemoglobin was not detected. In conclusion, inhalation of NO (up to 60 ppm) lowered P(ap) without directly affecting CBF, electrocortical activity, and redox status in the pulmonary vessels. CBF, however, can indirectly be influenced by NO-mediated changes in PCO2.     

Development of nested PCR assays for detection of bovine respiratory syncytial virus in clinical samples

Two nested PCR assays were developed for the detection of bovine respiratory syncytial virus (BRSV). Primers were selected from the gene encoding the F fusion protein (PCR-F) and the gene encoding the G attachment protein (PCR-G). Biotinylated oligonucleotide probes, termed F and G, were selected for the hybridization of the respective PCR products. The sensitivities of the PCR-F and PCR-G assays were similar, both detecting 0.1 tissue culture infective dose of the virus. The PCR-F assay amplified all bovine strains and one human strain (RS32) tested. No cross-reactions were observed with nine heterologous respiratory viruses. PCR-F products of bovine and human RSV strains were discriminated by using endonuclease restriction enzyme ScaI, which specifically cleaved, products of BRSV. Oligonucleotide probe F was also specific for products of BRSV. The PCR-G assay detected all bovine strains and none of the human strains tested. A faint electrophoretic band was also observed with products of Sendai virus. However, probe G did not hybridize with this product, only with products of BRSV. Nasal swabs collected from cattle with no symptoms and cattle in the acute stage of respiratory disease were analyzed for BRSV by the immunofluorescence (IF) method and by the PCR-F and PCR-G assays. The virus was detected by the PCR assays in 31 of 35 (89%) samples tested. Only 23 samples (66%) were positive by the IF method, and these samples were also positive by both the PCR-F and PCR-G assays. The 31 samples detected as positive by PCR originated from cattle presenting clinical signs of acute respiratory disease; the four PCR-negative samples originated from clinically asymptomatic neighboring cattle. All sampled animals subsequently seroconverted and became reactive to BRSV. Thus, the detection of BRSV by PCR correlated with clinical observations and was considerably more sensitive (66 versus 89%) than IF. These results indicate that both nested PCR assays provide rapid and sensitive means for the detection of BRSV infection in cattle. Considering its higher specificity, the PCR-F assay can be recommended as the method of choice in the analysis of clinical specimens of BRSV.     

Nitric oxide synthase activity in tissues of the blowfly Chrysomya megacephala (Fabricius, 1794).

Although insects lack the adaptive immune response of the mammalians, they manifest effective innate immune responses, which include both cellular and humoral components. Cellular responses are mediated by hemocytes, and humoral responses include the activation of proteolytic cascades that initiate many events, including NO production. In mammals, nitric oxide synthases (NOSs) are also present in the endothelium, the brain, the adrenal glands, and the platelets. Studies on the distribution of NO-producing systems in invertebrates have revealed functional similarities between NOS in this group and vertebrates. We attempted to localize NOS activity in tissues of na?ve (UIL), yeast-injected (YIL), and saline-injected (SIL) larvae of the blowfly Chrysomya megacephala, using the NADPH diaphorase technique. Our findings revealed similar levels of NOS activity in muscle, fat body, Malpighian tubule, gut, and brain, suggesting that NO synthesis may not be involved in the immune response of these larval systems. These results were compared to many studies that recorded the involvement of NO in various physiological functions of insects.     

Anthocyanin composition of Tempranillo, Garnacha and Cabernet Sauvignon grapes from high- and low-quality vineyards over two years

The anthocyanin composition of Tempranillo, Garnacha and Cabernet Sauvignon grapes over two vintages was studied. Samples were obtained during berry ripening from two vineyards that differed by producing fruit of high and low quality. The proportions of the individual compounds remained practically constant within a single vineyard along the sampling period, the changes in the anthocyanin composition being principally quantitative. Different multivariate statistical methods showed that the anthocyanin profile was primarily determined by variety. This genetic dependence was particularly verified when the sums of the non-acylated glucosides, the acetates and the p-coumaryl derivatives, were analysed. The mean relative content corresponding to these three anthocyanin fractions was always the same within each variety, independently either of the vineyard or the vintage year considered. Relating to the individual compounds, several permanent qualitative differences between vineyards in each variety were also found, although the difference in the total anthocyanin concentration was always much higher.     

Percutaneous transluminal angioplasty of the renal artery in transplanted kidneys

The objective of the work was to evaluate the contribution of percutaneous transluminal angioplasty (PTA) to treatment of hypertension and the graft function of a transplanted kidney. Angioplasty of the graft artery was performed in 39 patients. Technical success rate: 85%. Complications: 13%--in particular during the first years after introduction of the method. Twenty seven patients were followed up on a long-term basis. Changes of the median arterial pressure (MAP) were evaluated as well as glomerular filtration (GF) assessed by creatinine clearance. Mean values: [table: see text] A statistically significant (p < 0.01) reduction of the median arterial pressure (drop by > 10 mm Hg) along with reduction of the number of antihypertensive drugs was recorded in 70% of the patients during the first year and in 80% kidney recipients in investigations extending beyond one year. A significant increase of glomerular filtration (by > 20%) was found in 40% of the patients, on average the rise was insignificant. During the follow up period 13 kidney recipients were transferred to a dialyzation programme due to failure of the grafts as a result of rejection. CONCLUSION: Percutaneous transluminal angioplasty of a stenosis of the graft artery is the method of first choice in the treatment of hypertension. It is of fundamental importance also in rare cases in order to preserve or improve graft function and thus delay dialyzation treatment.