Fabrication and I-V Characterization of ZnO Nanorod Based Metal-Insulator-Semiconductor Junction

We report on the characteristics of a ZnO based metal insulator semiconductor (MIS) diode comprised of a heterostructure of n-ZnO nanorods/n-GaN. The MIS structure consisted of unintentional - doped n type ZnO nanorods grown on n-GaN sample using hydrothermal synthesis at low temperature (100°). The ZnO nanorod layer was vertically grown from the GaN sample, having the diameter 100nm and length 2µm. Then, an insulator layer for electrical isolation was deposited on the top of ZnO nanorod layer by using spin coating method. A metal layer (gold) was finally deposited on the top. The I-V dependences show a rectifying diode like behavior with a leakage current of 2.10⁻⁵ A and a threshold voltage of about 3V. Depend on the thickness of the insulator, the I-V dependences of the n-ZnO/n-GaN heterostructure was varied from rectifying behavior to Ohmic and nearly linear.Singapore-MIT Alliance (SMA

ZnO Nanorods Grown on p-GaN Using Hydrothermal Synthesis and Its Optoelectronic Devices Application

The ZnO nanorods with the length of 1-1.5 μm were deposited on p-GaN by hydrothermal synthesis at low temperature 100°C. The structural and optical properties of the as-grown ZnO rods were investigated by X-Ray diffraction (XRD) and photoluminescence (PL) spectra. After annealing treatment the as-grown films in air at 600°C, 30min, and the ZnO rods showed good crystallinity and optical properties with strong UV emission at 378 nm. In addition, a sharp UV emission peak at 369.45 nm with the FWHM 20 meV, which attributed to the bound exciton recombination, was also observed from the ZnO rods at 80K. Next, the e-beam evaporation method was used to deposit metal contact on n-ZnO and p-GaN. Here, we use Au and Ni/Au as metal contacts for n-ZnO and p-GaN, respectively. The current-voltage characteristics of the fabricated n-ZnO/p-GaN heterojunction revealed rectifying behavior with a leakage current of 10⁻⁸ A at -10V, a forward current 4x10⁻⁶ A at 10V bias. The heterojunction also showed a good photoresponse, with the change of the current – voltage characteristics under ultraviolet illumination. Under UV illumination, the forward turn on voltage changed to 7.5V. This result showed the ability to manipulate the electron transport in the ZnO based heterojunction devices.Singapore-MIT Alliance (SMA

Diagnosis and treatment of chlamydia and gonorrhoea in general practice in England 2000–2011: a population-based study using data from the UK Clinical Practice Research Datalink

Objectives: To determine the relative contribution of general practices (GPs) to the diagnosis of chlamydia and gonorrhoea in England and whether treatment complied with national guidelines. Design: Analysis of longitudinal electronic health records in the Clinical Practice Research Datalink (CPRD) and national sexually transmitted infection (STI) surveillance databases, England, 2000–2011. Setting: GPs, and community and specialist STI services. Participants: Patients diagnosed with chlamydia (n=1 386 169) and gonorrhoea (n=232 720) at CPRD GPs, and community and specialist STI Services from 2000–2011. Main outcome measures: Numbers and rates of chlamydia and gonorrhoea diagnoses; percentages of patients diagnosed by GPs relative to other services; percentage of GP patients treated and antimicrobials used; percentage of GP patients referred. Results: The diagnosis rate (95% CI) per 100 000 population of chlamydia in GP increased from 22.8 (22.4–23.2) in 2000 to 29.3 (28.8–29.7) in 2011 (p<0.001), while the proportion treated increased from 59.5% to 78.4% (p=0.001). Over 90% were prescribed a recommended antimicrobial. Over the same period, the diagnosis rate (95% CI) per 100 000 population of gonorrhoea in GP ranged between 3.2 (3–3.3) and 2.4 (2.2–2.5; p=0.607), and the proportion treated ranged between 32.7% and 53.6% (p=0.262). Despite being discontinued as a recommended therapy for gonorrhoea in 2005, ciprofloxacin accounted for 42% of prescriptions in 2007 and 20% in 2011. Over the study period, GPs diagnosed between 9% and 16% of chlamydia cases and between 6% and 9% of gonorrhoea cases in England. Conclusions: GP makes an important contribution to the diagnosis and treatment of bacterial STIs in England. While most patients diagnosed with chlamydia were managed appropriately, many of those treated for gonorrhoea received antimicrobials no longer recommended for use. Given the global threat of antimicrobial resistance, GPs should remain abreast of national treatment guidelines and alert to treatment failure in their patients

Characterization of ZnO Nanorods Grown on GaN Using Aqueous Solution Method

Uniformly distributed ZnO nanorods with diameter 70-100 nm and 1-2μm long have been successfully grown at low temperatures on GaN by using the inexpensive aqueous solution method. The formation of the ZnO nanorods and the growth parameters are controlled by reactant concentration, temperature and pH. No catalyst is required. The XRD studies show that the ZnO nanorods are single crystals and that they grow along the c axis of the crystal plane. The room temperature photoluminescence measurements have shown ultraviolet peaks at 388nm with high intensity, which are comparable to those found in high quality ZnO films. The mechanism of the nanorod growth in the aqueous solution is proposed. The dependence of the ZnO nanorods on the growth parameters was also investigated. While changing the growth temperature from 60°C to 150°C, the morphology of the ZnO nanorods changed from sharp tip (needle shape) to flat tip (rod shape). These kinds of structure are useful in laser and field emission application.Singapore-MIT Alliance (SMA

Growth of ZnO Nanorods on GaN Using Aqueous Solution Method

Uniformly distributed ZnO nanorods with diameter 80-120 nm and 1-2µm long have been successfully grown at low temperatures on GaN by using the inexpensive aqueous solution method. The formation of the ZnO nanorods and the growth parameters are controlled by reactant concentration, temperature and pH. No catalyst is required. The XRD studies show that the ZnO nanorods are single crystals and that they grow along the c axis of the crystal plane. The room temperature photoluminescence measurements have shown ultraviolet peaks at 388nm with high intensity, which are comparable to those found in high quality ZnO films. The mechanism of the nanorod growth in the aqueous solution is proposed. The dependence of the ZnO nanorods on the growth parameters was also investigated. While changing the growth temperature from 60°C to 150°C, the morphology of the ZnO nanorods changed from sharp tip with high aspect ratio to flat tip with smaller aspect ratio. These kinds of structure are useful in laser and field emission application.Singapore-MIT Alliance (SMA

Porcine innate and adaptative immune responses to influenza and coronavirus infections

Both innate and adaptative immune responses contribute to the control of infectious diseases, including by limiting the spreading of zoonotic diseases from animal reservoirs to humans. Pigs represent an important animal reservoir for influenza virus infection of human populations and are also naturally infected by coronaviruses, an important group of viruses, which includes the recently emerged severe acute respiratory syndrome (SARS) virus. Studies on both innate and adaptative immune responses of pigs to influenza virus and coronaviruses contribute, therefore, to a better control of these infections in their natural hosts and will be briefly reviewed in this article. Pro-inflammatory cytokines, including type I interferon (IFN), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6), were found in lung secretions of influenza virus infected pigs, and correlated with the intensity of clinical signs, whereas prior vaccination against influenza strongly reduced the production of infectious virus and cytokines in the lungs upon challenge, which was associated with clinical protection. An early type I IFN production was also found in coronavirus infected pigs, including at mucosal sites. IFN induction by coronavirus is shown to involve interaction between a viral glycoprotein and a leukocyte subset, likely equivalent to plasmacytoid dendritic cells, present in the mucosae and associated lymphoid tissues. Given the IFN mediated antiviral and immunomodulatory effects, the use of IFN or IFN inducers may prove an efficient strategy for a better control of influenza virus and coronavirus infections in pigs. Because influenza and coronaviruses target mucosal surfaces, adaptative immune responses have to be characterized at mucosal sites. Thus, nasal and pulmonary antibody responses were analyzed in influenza virus infected or vaccinated pigs showing short-lived, but potentially protective local IgA and IgG antibody (Ab) responses. Interestingly, primary influenza virus infection induced long-lived increase of lung CD8(+) T cells and local lymphoproliferative responses. Pigs infected by a respiratory coronavirus (PRCV) showed virus-specific IgG Ab-secreting cells in the bronchial lymph nodes, whereas the transmissible gastroenteritis coronavirus (TGEV) induced more IgA Ab-secreting cells in gut tissues, which illustrates the importance of the route of antigen administration for inducing local immune effector mechanisms. Porcine viral infections provide, therefore, valuable models for evaluating the immune parameters that are important for controlling transmission of important viral zoonotic infections

Review of the potential health impact of B-casomorphins and related peptides : report of the DATEX working group on B-casomorphins

v2009o

Search for low-mass PMS companions around X-ray selected late B stars

We have observed 49 X-ray detected bright late B-type dwarfs to search for close low-mass pre-main sequence (PMS) companions using the European Southern Observatory's ADONIS (Adaptive Optics Near Infrared System) instrument. We announce the discovery of 21 new companions in 9 binaries, 5 triple, 4 quadruple system and 1 system consisting of five stars. The detected new companions have K magnitudes between 6.5 mag and 17.3 mag. and angular separations ranging from 0.2 and 14.1 arcsec (18-2358 AU).Comment: Accepted for publication in Astronomy and Astrophysic

Co-culture of mechanically injured cartilage with joint capsule tissue alters chondrocyte expression patterns and increases ADAMTS5 production

We studied changes in chondrocyte gene expression, aggrecan degradation, and aggrecanase production and activity in normal and mechanically injured cartilage co-cultured with joint capsule tissue. Chondrocyte expression of 21 genes was measured at 1, 2, 4, 6, 12, and 24 h after treatment; clustering analysis enabled identification of co-expression profiles. Aggrecan fragments retained in cartilage and released to medium and loss of cartilage sGAG were quantified. Increased expression of MMP-13 and ADAMTS4 clustered with effects of co-culture, while increased expression of ADAMTS5, MMP-3, TGF-β, c-fos, c-jun clustered with cartilage injury. ADAMTS5 protein within cartilage (immunohistochemistry) increased following injury and with co-culture. Cartilage sGAG decreased over 16-days, most severely following injury plus co-culture. Cartilage aggrecan was cleaved at aggrecanase sites in the interglobular and C-terminal domains, resulting in loss of the G3 domain, especially after injury plus co-culture. Together, these results support the hypothesis that interactions between injured cartilage and other joint tissues are important in matrix catabolism after joint injury