Molecular Biology and Pathogenesis of Retroviruses

Retroviruses consist of a varied family of enveloped RNA viruses with positive-sense RNAs that replicate in a host cell through the process of reverse transcription. Retroviruses belong to the Retroviridae family that typically carries their genetic material in the form of ribonucleic acid, while the genetic material of their hosts is in the form of deoxyribonucleic acid. Infections with a number of retroviruses can lead to serious conditions, such as AIDS, a range of malignancies, neurological diseases, and added clinical conditions. In addition, some can even become integrated as DNA in the germ line and passed as endogenous viruses from generation to generation. Surprisingly, retroviruses do not appear to straightforwardly activate host innate defenses. On the other hand, attention in these viruses extends beyond their disease causing capabilities. For example, studies on the retroviruses led to the discovery of oncogenes, understanding of mechanisms that regulate eukaryotic gene expression, and these are proving to be valuable research tools in molecular biology and have been used successfully in gene therapy. The central goals of retrovirology today are the treatment and the prevention of human and non-human diseases and to use this virus in research

Abrasive Water Jet Machining of Carbon Epoxy Composite

An experimental study of abrasive water jet machining of carbon epoxy composite is presented. Process parameters namely hydraulic pressure, traverse rate, stand-off distance and abrasive mass flow rate are considered for this study. Taguchi approach and analysis of variance are used to study the influence of process parameters on response characteristics including surface roughness and kerf taper. It is found that hydraulic pressure and traverse rate are most significant parameters to control surface roughness and kerf taper. Microscopic features of the machined surfaces are evaluated using scanning electron microscope and compared with sample surfaces machined by conventional method using diamond edge cutter.A set of process parameters is optimised to achieve minimum surface roughness and kerf taper. Confirmation tests are performed to verify the optimum set of process parameters. Defects like delamination, fibre pull out and abrasive embedment are also studied using scanning electron microscope

Resonant Raman of OH/OD vibrations and photoluminescence studies in LiTaO3 thin film

Resonant Raman spectra (RRS) of O-H and O-D vibration and libration modes, their combinations and higher harmonics have been observed in LiTaO3 polycrystalline thin films. RRS peaks are superimposed on photoluminescence (PL) spectrum. Monochromatic light from a xenon lamp is used as excitation source. PL spectrum shows two broad peaks, first near the band gap in UV (4.4-4.8eV) and another in the sub band gap region (< 4.0 eV). Band gap PL along with RRS peaks are reported for the first time. Photoluminescence excitation spectrum (PLE) shows a peak at 4.8 eV. Peak positions and full width at half maximum (FWHM) of RRS peaks depend upon the excitation energy. Dispersions of the fundamental and the third harmonic of the stretching mode of O-H with excitation energy are about 800 cm-1/eV and 2000 cm-1/eV respectively. This dispersion is much higher than reported in any other material.Comment: 20 page

Interactive effects of cocaine on HIV infection: implication in HIV-associated neurocognitive disorder and neuroAIDS.

Substantial epidemiological studies suggest that not only, being one of the reasons for the transmission of the human immunodeficiency virus (HIV), but drug abuse also serves its role in determining the disease progression and severity among the HIV infected population. This article focuses on the drug cocaine, and its role in facilitating entry of HIV into the CNS and mechanisms of development of neurologic complications in infected individuals. Cocaine is a powerfully addictive central nervous system stimulating drug, which increases the level of neurotransmitter dopamine (DA) in the brain, by blocking the dopamine transporters (DAT) which is critical for DA homeostasis and neurocognitive function. Tat protein of HIV acts as an allosteric modulator of DAT, where as cocaine acts as reuptake inhibitor. When macrophages in the CNS are exposed to DA, their number increases. These macrophages release inflammatory mediators and neurotoxins, causing chronic neuroinflammation. Cocaine abuse during HIV infection enhances the production of platelet monocyte complexes (PMCs), which may cross transendothelial barrier, and result in HIV-associated neurocognitive disorder (HAND). HAND is characterized by neuroinflammation, including astrogliosis, multinucleated giant cells, and neuronal apoptosis that is linked to progressive virus infection and immune deterioration. Cocaine and viral proteins are capable of eliciting signaling transduction pathways in neurons, involving in mitochondrial membrane potential loss, oxidative stress, activation of JNK, p38, and ERK/MAPK pathways, and results in downstream activation of NF-κB that leads to HAND. Tat-induced inflammation provokes permeability of the blood brain barrier (BBB) in the platelet dependent manner, which can potentially be the reason for progression to HAND during HIV infection. A better understanding on the role of cocaine in HIV infection can give a clue in developing novel therapeutic strategies against HIV-1 infection in cocaine using HIV infected population

Dielectric characterization and molecular interaction behaviour in binary mixtures of methyl acetate with 1-butanol and 1-pentanol

The dielectric constant (ɛs) and relaxation time () of binary mixtures of methyl acetate with alcohols (1-butanol and 1-pentanol) have been investigated at fifteen molar concentrations over the entire mixing range at 288 K, 298 K, 308 K and 318 K using time domain reflectometery technique over the frequency range from 10 MHz to 10 GHz. The relaxation in these mixtures can be described by a single relaxation time using the Debye model. The concentration dependent plots of excess dielectric constant (ɛE), excess inverse relaxation time (1/)E, Kirkwood correlation factor (geff), thermodynamic parameters such as enthalpy of activation (H) and Gibbs free energy (G) of activation and Bruggman factor (fB) have been used to explore the complexes formed between unlike molecules, dipolar ordering, hydrogen bond molecular connectivity’s and their strength in the binary mixtures. Results confirm that there are strong hydrogen-bond interactions between unlike molecules of ester-alcohol mixtures

The Utility of Repeat Endoscopic Ultrasound-Guided Fine Needle Aspiration for Suspected Pancreatic Cancer

Background. The utility of repeat EUS in patients with suspicion for pancreatic cancer after non-diagnostic EUS-FNA study is not well established. Aim. Determine the accuracy of repeat EUS-FNA in patients with suspected pancreatic cancer and prior non-diagnostic EUS-FNA. Methods. Retrospective cohort study. Results. From 2002 to 2008 in our institution 28 patients underwent repeat EUS-FNA for suspected pancreatic cancer. Initial EUS showed a pancreatic mass in 24 (85.71%), no mass in 3 (10.71%) and possible mass in 1 (3.58%). FNA was performed and was negative for malignancy in all patients. Repeat EUS showed pancreatic mass in 27 patients (96.42%) and no mass in 1 (3.58%). FNA was performed in all patients and cytology was positive for malignancy in 6 (21.43%). Out of the 28 patients, 17 (60.71%) were eventually confirmed to have cancer. Overall repeat EUS-FNA correctly determined the true final status in 17 out of 28 patients providing sensitivity for the diagnosis of cancer of 35% (95% CI 14%–62%), specificity 100% (95% CI 72%–100%), and overall accuracy of 61%, (95% CI 28%–72%). Conclusion. Repeat EUS-FNA provides reasonable accuracy and may be worthwhile in patients with suspected pancreatic cancer who had had prior negative EUS-FNA