A pressure-free long-time stable reduced-order model for two-dimensional Rayleigh-Bénard convection

The present work presents a stable proper orthogonal decomposition (POD)-Galerkin based reduced-order model (ROM) for two-dimensional Rayleigh-Bénard convection in a square geometry for three Rayleigh numbers: 104 (steady state), 3×105 (periodic), and 6×106 (chaotic). Stability is obtained through a particular (staggered-grid) full-order model (FOM) discretization that leads to a ROM that is pressure-free and has skew-symmetric (energy-conserving) convective terms. This yields long-time stable solutions without requiring stabilizing mechanisms, even outside the training data range. The ROM's stability is validated for the different test cases by investigating the Nusselt and Reynolds number time series and the mean and variance of the vertical temperature profile. In general, these quantities converge to the FOM when increasing the number of modes, and turn out to be a good measure of accuracy. However, for the chaotic case, convergence with increasing numbers of modes is relatively difficult and a high number of modes is required to resolve the low-energy structures that are important for the global dynamics.

Isolation of bluetongue virus-1 from cattle in India and phylogenetic analysis of the complete coding sequence of the segment-2 gene

The isolation of BTV-1 serotype from cattle in India and its phylogenetic relationship based on VP2 gene has been reported. Virus (JBP42/12/Ind) is isolated in BHK-21 cell line from blood sample tested positive for BTV antigen in sandwich ELISA from asymptomatic cattle. Full length VP2 gene of cattle isolate was amplified, cloned and sequenced. On BLAST analysis virus isolate was identified as BTV-1 serotype. Phylogenetic tree based on complete VP2 coding region segregated Indian isolates, Australian isolates and African/European isolates in three distinct clusters. Segregation of Indian BTV-1 isolates at close proximity to the monophyletic cluster of Australian BTV-1 isolates indicates the present isolate as "eastern topotype' of BTV. Multiple alignments of VP2 gene nucleotide sequences suggest that, Indian BTV-1 isolate is more closely related to Australian BTV-1 isolates; where 14.1% to 14.4% and 6.8% to 7.4% divergence was observed at nucleotide and deduced amino acid sequence level respectively.

Isolation of bluetongue virus serotype 1 from aborted goat fetuses

Abortions and stillbirths were noticed in pregnant goats on a farm in the state of Gujarat, India. About 50% of the pregnant goats aborted or gave birth to dead kids. Bluetongue virus (BTV) antibody in the sera of affected goats was detected using a competitive enzyme-linked immunosorbent assay (ELISA). Viral antigen in the blood of these goats and in the aborted fetal spleens was detected using a sandwich ELISA. Two viruses (SKN-9, SKN-10) were isolated in cell culture from aborted fetal spleens and were confirmed as Orbivirus by demonstration of ten bands in RNA polyacrylamide gel electrophoresis and identified as BTV-1 by sequencing of the VP2 gene. Sequence analyses revealed thatthese isolates were very closely related to a BTV-1 (strain SKN-8) isolated from Culicoides vectors captured on the same farm one month after the occurrence of abortion. Isolation of BTV-1 from fetuses is probably evidence of transplacental transmission of the wild-type strain, because attenuated or laboratory-adapted BTV-1 strains have never been used in this region. This may have important implications in the epidemiology of bluetongue, considering the presence of many BTV serotypes in India.

An update on natural occurrence and biological activity of chromones

The chemistry of chromones is very well known. This system is widely used in organic chemistry as an intermediate compound for the synthesis of numerous hetrocycles. On the other hand, chromones were extensively studied as bioactive compounds. They possess remarkable biological activities, such as antimicrobial, antiviral, anticancer, anti-inflammatory, antioxidant, etc. This comprehensive review describes the current status and knowledge of natural occurrence, and biological activities of chromones. Recent advances made over the last decade i.e. January 1999 to December 2009 are critically discussed and we have covered about 176 references and more than 350 compounds reported during this period.

Resistance to Antituberculosis Drugs in Pulmonary Tuberculosis

BACKGROUND

Incidence of drug resistance and pattern of susceptibility to antitubercular drugs in pulmonary tuberculosis amongst soldiers and their families was studied for four years at a military hospital in northwest India.

METHODS

Identification and susceptibility tests were carried out as per procedures laid out in laboratory manual of Tuberculosis Research Centre (TRC), Chennai.

RESULTS

Of the 172 strains of Mycobacterium tuberculosis (MTB) isolated from sputum samples, 150 (87.21%) were sensitive and 22 (12.79%) showed resistance to one or more antitubercular drugs. Acquired drug resistance was observed in 7 (31.82%) and primary drug resistance in 15 (68.18%) cases. Among 22 drug resistant cases, who were on short course chemotherapy (SCC), resistance to single drug was observed in 12 (54.54%), two drugs in 7 (31.82%) and to three or more drugs in 3 (13.64%) isolates. Fourteen (18.14%) strains were resistant to Streptomycin, 8 (4.65%) to Rifampicin, 11 (6.40%) to Isoniazid, 1 (0.58%) to Pyrazinamide and 2 (1.16%) to Ethambutol. Multidrug resistance was observed in 5 (2.91%) cases, of which resistance to Isoniazid and Rifampicin was present in 2 (1.16%) and their combination with other drugs in other 3 (1.74%) isolates.

CONCLUSIONS

Drug susceptibility pattern to antitubercular drugs is discussed and compared with studies from other centres.

Intracranial bleed complicating the use of Crutchfield tongs

Skeletal traction using the metal tongs attached to the skull is commonly used in the management of the fracture dislocation of the cervical spine. Rare complication of this procedure, the intracranial bleed has scantily being reported in the English literature. We report a case of such a complication in a 105 years old man who required Crutchfield application following fall. Presenting symptoms consisted of sudden deterioration of sensorium, with fatal outcome.

In vivo proton magnetic resonance spectroscopy in a known case of intracranial hydatid cyst

We are presenting magnetic resonance spectroscopy (MRS) findings of a known case of hydatid cyst operated twice in the past. A 22-years-old male patient had presented with recurrent symptoms of generalized seizures and raised intracranial tension. MRI with MRS of the lesion was performed that showed a recurrent loculated cystic lesion in right parieto-occipital lobe. MRS through the lesion was performed using repetition time (TR) of 1500 ms and time to echo (TE) of 135 ms using 2 x 2 x 2 cm voxel, from the margin of the lesion. MRS showed mildly elevated choline (Cho), depressed creatine (Cr) and N-acetyl aspartate (NAA), a large peak of lactate, pyruvate and acetate peaks.

"Significance of serum gamma glutamyl transpeptidase in cholestatic jaundice"

In conclusion, our study showed that serum G.G.T rises in cholestasis, and the rise is significantly higher in extraphepatic cholestasis as compared to intrahepatic cholestasis. Serum G.G.T has not shown any superiority over alkaline phosphatase in the evaluation of cholestatic liver disease. However, two considerations must caution against the use of serum G.G.T. alone for evaluation of hepatobiliary disease. The first of these is the lack of specificity for hepatobiliary disease. Serum G.G.T. activity can be elevated in some non-hepatic disorders such as acute pancreatitis, congestive cardiac failure, myocardial infarction, diabetes mellitus and alcoholism. Determination of serum G.G.T. in these patients is of no value. Second, the possibility that changes in serum G.G.T. activity results from drug administration in man.

Fatal fat embolism associated with polymethyl methacrylate bone cement

Three fatalities after procedures involving the use of polymethyl methacrylate cement are reported. Autopsy studies showed varying degrees of pulmonary fat embolism although lack of correction of operative blood loss was the major factor.

Pathological anatomy of the aging meniscus

In 21 autopsy subjects and 25 anatomical cadavers, both knee joints were dissected extensively to find: a) degenerative changes in the menisci of knee joints, especially horizontal tears and b) associated degenerative changes in the articular surfaces of the knee joint, in order to attempt a correlation between the two lesions. Thirty-nine horizontal tears of the meniscus in 21 patients were found, of which 32 were in the medial meniscus. There was no articular damage visible in three, minimal in eight, moderate in seven and severe in three subjects. The highest incidence was in the seventh and eighth decades with black males showing a slight preponderance. The degenerative meniscus with a horizontal tear is a part of the overall degenerative process in the knee joint and should be treated as such.