Reactively Magnetron Sputter-Deposited Ti (C,N) Nanocomposite Thin Films: Composition and Thermal Stability

Titanium carbonitride thin films were grown by reactive magnetron sputtering deposition of titanium carbide target in Ar/N2 gas mixture on p-type silicon (100) substrates. With the increase of sputtering power up to 125W, the deposition rate and films thickness reached a maximum of 14nm/min and 430nm, respectively. A thick film of about 2200nm could be deposited for 120 min at the optimum deposition pressure of 20mTorr. Cathode current decreased from about 290mA to reach a value of about 235mA as the N2 flow percentage increased from 0 to 100%. X-ray diffraction analyses of the deposited films confirmed the formation of titanium carbide and carbonitride layers as the nitrogen gas concentrations in the process gas were increased. SEM image of the deposited titanium carbonitride thin film for 5 min deposition time showed that the film started to grow as tiny particles of size as low as about 140nm, which in later stage coalesced together to form bigger grains and finally a continuous film. The deposited film shows good thermal stability upon annealing in air and in vacuum at 700oC for 2 hours

Enhancement of FMIPv6 by Utilising Concurent Binding Update Process

The world is progressing toward the Mobile Internet Protocol Television (MIPTV) era where people are able to watch television while roaming. The MIPTV technology requires high bandwidth and low latency handover. This paper enhances the binding updates process in the Fast Handover Mobile IPv6 (FMIPv6) to improve its handover process performance in term of secureness and robustness, by implementing concurant binding update process thru the use of the International Mobile Subscriber Identifier (IMSI). Simulation results show that the proposed idea reduces the handover latency to about 63% compared to standard FMIPv6

Efficacy of prophylactic phototherapy for prevention of hyperbilirubinemia in very low birth weight newborns

Background: Jaundice is a common clinical condition in newborn occurring in approximately 60% of term and 80% of preterm infants. Unconjugated hyperbilirubinemia is universally common in all preterm infants especially in newborns with very low biLth weight. Low birth weight and premature infants are at major risk for exaggerated hyperbilirubinemia that can lead to bilirubin encephalopathy. Significant heterogeneity in the approach to the treatment of jaundiced neonates exists throughout the world. Phototherapy is the most common treatment for neonatal hyperbilirubinemia and could be most effective in preventing the sequelae of hyperbilirubinemia if initiated prophylactically. This randomized clinical trial has been proposed with the objective of assessing the efficacy of prophylactic photo therapy in preventing significant rise of unconjugated hyperbilirubinemia in premature neonates weighing less than 1500 gram and therefore to decrease the need for exchange transfusion and finally to reduce hospital stay due to hyperbilirubinemia. Methods: This randomized controlled clinical trial enrolled sixty newborns with birth weight less than 1500 gram. They were divided into two groups: 1) Prophylactic group, in whom phototherapy was started within 24 hours of birth and continued for 7 days and 2) Control group in whom therapeutic phototherapy was started considering serum bilirubin level and other clinical condi­tions as per institutional guidelines. Mean value of total serum bilirubin (TSB), duration of phototherapy, the need for exchange transfusion and duration of hospital stay in both groups were analyzed.Results: The maximum mean TSB level in prophylactic group was observed on 7th day and in control group it was observed on 3rd day of life. The total serum bilirubin levels were significantly lower in the 3rd and 5th days of life in the prophylactic group in comparison to control group (P value 0.001). Total serum bilirubin level exceeded therapeutic range in 6 (21 %) and 14 (50 %) newborns of the prophylactic group and control groups respectively (P value 0.026). No documented side effects of prophylactic photo­therapy was observed. Conclusion: The use of prophylactic photo therapy for infants weighing less than 1500 grn is effec­tive and sate when compared to the control group, considering satisfactory maintenance of low total serum bilimbin levels during first 7 days of life

Effect of Reducing Atmosphere on the Magnetism of Zn1-xCoxO Nanoparticles

We report the crystal structure and magnetic properties of Zn1-xCoxO nanoparticles synthesized by heating metal acetates in organic solvent. The nanoparticles were crystallized in wurtzite ZnO structure after annealing in air and in a forming gas (Ar95%+H5%). The X-ray diffraction and X-ray photoemission spectroscopy (XPS) data for different Co content show clear evidence for the Co+2 ions in tetrahedral symmetry, indicating the substitution of Co+2 in ZnO lattice. However samples with x=0.08 and higher cobalt content also indicate the presence of Co metal clusters. Only those samples annealed in the reducing atmosphere of the forming gas, and that showed the presence of oxygen vacancies, exhibited ferromagnetism at room temperature. The air annealed samples remained non-magnetic down to 77K. The essential ingredient in achieving room temperature ferromagnetism in these Zn1-xCoxO nanoparticles was found to be the presence of additional carriers generated by the presence of the oxygen vacancies.Comment: 11 pages, 6 figures, submitted to Nanotechnology IO

Characterization of the multidrug efflux transporter styMdtMfrom Salmonella enterica serovar Typhi

Salmonellae are foodborne pathogens and the major cause of gastroenteritis in humans. Salmonellae express multidrug efflux transporters that play a key role in their drug resistance, which is becoming an increasing problem for therapeutic intervention. Despite their biomedical importance, the mechanisms underlying substrate transport by multidrug efflux transporters remain poorly understood. Here, we describe the first characterization of a multidrug transporter belonging to the major facilitator superfamily from the genus Salmonella. We show that several clinical Salmonella Typhi (S. Typhi) isolates constitutively express the styMdtM (STY4874) gene, which encodes a known multidrug-resistance (MDR) transporter. Guided by the structure of the Escherichia coli (E. coli) homolog, we studied two residues critical for substrate transport, Asp25 and Arg111. Mutation of Asp25 to glutamate did not affect the transport function of styMdtM, whereas mutation to alanine reduced its transport activity, suggesting that a negative charge at this position is critical for substrate translocation across the membrane. Substrate-affinity measurements by intrinsic fluorescence spectroscopy showed that the Asp25Ala mutant retained its capacity to bind substrate, albeit at a lower level. Mutation of Arg111 to alanine resulted in a decrease in secondary structure content of the transporter, and mutation to lysine completely destabilized the structure of the transporter. A homology model of styMdtM suggests that Arg111 is important for stabilizing the transmembrane domain by mediating necessary interactions between neighboring helices. Together, our studies provide new structural and mechanistic insights into the Salmonella MDR transporter styMdtM

Retinopathy of prematurity and its association with neonatal factors

Retinopathy of prematurity is considered as an important cause of blindness. This prospective study was undertaken to document the frequency and the associated factors of retinopathy of prematurity among 97 preterm newborn weighing <2000 g and/or with a gestation of <35 weeks. The first eye examination was performed by an ophthalmologist at 4 weeks of postnatal age for the infants born at ?30 weeks of gestation or birth weight ?1200 g and at 3 weeks of postnatal age for the infants <30 weeks of gestation or birth weight <1200 g. The overall incidence of retinopathy of prematurity was 23.7%. Premature newborn with retinopathy was having significant low mean birth weight (p=0.001) and the mean gestational age (p=<0.001) when compared with newborns without retinopathy of prematurity. Newborns with retinopathy of prematurity were requiring a longer duration of oxygen (p=0.005) than that of non-retinopathy of prematurity newborns. Logistic regression shows the duration of oxygen in the hospital and lower gestational age were independent risk factors of retinopathy of prematurity. Prematurity and longer duration of oxygen administration were the risk factors for the development of retinopathy of prematurity

C-Terminal Domain of the Human Zinc Transporter hZnT8 Is Structurally Indistinguishable from Its Disease Risk Variant (R325W)

The human zinc transporter 8 (hZnT8) plays important roles in the storage of insulin in the secretory vesicles of pancreatic β cells. hZnT8 consists of a transmembrane domain, with its N- and C-termini protruding into the cytoplasm. Interestingly, the exchange of arginine to tryptophan at position 325 in the C-terminal domain (CTD) increases the risk of developing type 2 diabetes mellitus (T2D). In the present study, the CTDs of hZnT8 (the wild-type (WT) and its disease risk variant (R325W)) were expressed, purified, and characterized in their native forms by biophysical techniques. The data reveal that the CTDs form tetramers which are stabilized by zinc binding, and exhibit negligible differences in their secondary structure content and zinc-binding affinities in solution. These findings provide the basis for conducting further structural studies aimed at unravelling the molecular mechanism underlying the increased susceptibility to develop T2D, which is modulated by the disease risk variant