SEARCHGTr: a program for analysis of glycosyltransferases involved in glycosylation of secondary metabolites

SEARCHGTr is a web-based software for the analysis of glycosyltransferases (GTrs) involved in the biosynthesis of a variety of pharmaceutically important compounds like adriamycin, erythromycin, vancomycin etc. This software has been developed based on a comprehensive analysis of sequence/structural features of 102 GTrs of known specificity from 52 natural product biosynthetic gene clusters. SEARCHGTr is a powerful tool that correlates sequences of GTrs to the chemical structures of their corresponding substrates. This software indicates the donor/acceptor specificity and also identifies putative substrate binding residues. In addition, it provides interfaces to other public databases like GENBANK, SWISS-PROT, CAZY, PDB, PDBSum and PUBMED for extracting various information on GTrs homologous to the query sequence. SEARCHGTr would provide new dimension to our previously developed bioinformatics tool NRPS-PKS. Together, these tools facilitate comprehensive computational analysis of proteins involved in biosynthesis of aglycone core and its downstream glycosylations. Apart from presenting opportunities for rational design of novel natural products, these tools would assist in the identification of biosynthetic products of secondary metabolite gene clusters found in newly sequenced genomes. SEARCHGTr can be accessed at

Size-distribution of submicron aerosol particles over the Indian Ocean during IFP-99 of INDOEX

Measurements of the size-distribution of submicron aerosol particles of diameter from 0.003 to 1 μm are made over the Indian Ocean during the IFP-99 of the Indian Ocean Experiment (INDOEX). Measurements are made during the onward journey from Goa to Port Louis, Mauritius from 20 January to 11 February 1999 onboard ORV Sagar Kanya and during the return journey from Port Louis to Male from 22 February to 1 March 1999 onboard Ronald H. Brown. Observations show large concentrations in the range of 2-6 × 103 particles/cm3 over the Indian Ocean in the northern hemisphere and these drop down to about 500 particles/cm3 in the southern hemisphere. However, the aerosol concentrations show a peak of about 3 × 103 particles/cm3 at 13°S. In the northern hemisphere, the concentration of particles of diameter < 0.0749 μm increases from 14°N to 1°N and then steeply falls. On the other hand, the concentration of particles of diameter > 0.0749 μm keeps decreasing up to 6°S. Size distributions of particles at open sea in the northern hemisphere show a maximum at 0.133 μm and minimum at 0.0422 μm and are generally openended at the smaller size end. The size-distributions of particles are sometimes relatively flat from 0.0133 to 0.237 μm when the particle concentrations are low in the southern hemisphere. The transport and accumulation of aerosol particles in the Inter-Tropical Convergence Zone is discussed. The relative abundance of large versus small particles is examined with respect to the variation of surface atmospheric pressure along the route

The role of electron-electron scattering in spin transport

We investigate spin transport in quasi 2DEG formed by III-V semiconductor heterojunctions using the Monte Carlo method. The results obtained with and without electron-electron scattering are compared and appreciable difference between the two is found. The electron-electron scattering leads to suppression of Dyakonov-Perel mechanism (DP) and enhancement of Elliott-Yafet mechanism (EY). Finally, spin transport in InSb and GaAs heterostructures is investigated considering both DP and EY mechanisms. While DP mechanism dominates spin decoherence in GaAs, EY mechanism is found to dominate in high mobility InSb. Our simulations predict a lower spin relaxation/decoherence rate in wide gap semiconductors which is desirable for spin transport.Comment: to appear in Journal of Applied Physic

Interfacial control of vortex-limited critical current in type-II superconductor films

In a small subset of type-II superconductor films, the critical current is determined by a weakened Bean-Livingston barrier posed by the film surfaces to vortex penetration into the sample. A film property thus depends sensitively on the surface or interface to an adjacent material. We theoretically investigate the dependence of vortex barrier and critical current in such films on the Rashba spin-orbit coupling at their interfaces with adjacent materials. Considering an interface with a magnetic insulator, we find the spontaneous supercurrent resulting from the exchange field and interfacial spin-orbit coupling to substantially modify the vortex surface barrier, consistent with a previous prediction. Thus, we show that the critical currents in superconductor-magnet heterostructures can be controlled, and even enhanced, via the interfacial spin-orbit coupling. Since the latter can be controlled via a gate voltage, our analysis predicts a class of heterostructures amenable to gate-voltage modulation of superconducting critical currents. It also sheds light on the recently observed gate-voltage enhancement of critical current in NbN superconducting film

New insights into electron spin dynamics in the presence of correlated noise

The changes of the spin depolarization length in zinc-blende semiconductors when an external component of correlated noise is added to a static driving electric field are analyzed for different values of field strength, noise amplitude and correlation time. Electron dynamics is simulated by a Monte Carlo procedure which keeps into account all the possible scattering phenomena of the hot electrons in the medium and includes the evolution of spin polarization. Spin depolarization is studied by examinating the decay of the initial spin polarization of the conduction electrons through the D'yakonov-Perel process, the only relevant relaxation mechanism in III-V crystals. Our results show that, for electric field amplitude lower than the Gunn field, the dephasing length shortens with the increasing of the noise intensity. Moreover, a nonmonotonic behavior of spin depolarization length with the noise correlation time is found, characterized by a maximum variation for values of noise correlation time comparable with the dephasing time. Instead, in high field conditions, we find that, critically depending on the noise correlation time, external fluctuations can positively affect the relaxation length. The influence of the inclusion of the electron-electron scattering mechanism is also shown and discussed.Comment: Published on "Journal of Physics: Condensed Matter" as "Fast Track Communications", 11 pages, 9 figure

Establishing Relationship between Pressure & Normal Shocks for Convergent-Divergent Nozzle-

Objective of the present study is to analyze experimentally the pressure variation in a varying area circular passage at different supply pressures and compare these with the theoretical solutions. It has been observed that flow of stream of the normal shock is always supersonic while in downstream is always sub-sonic thus shocks slow down the flow rates by sudden increase in pressure ratios. Shock strength is determined uniquely by the mach no. higher the mach no. of upstream of supersonic flow , greater is the shock strength & lower is downstream subsonic mach no. Theoretically minimum pressure is always present at the throat during subsonic condition. But experimentally the position of minimum pressure might be varied because of variation in the stagnation properties of the fluid. This project also includes flow phenomenon over the entire length of nozzle for varying back pressure

Indigenous Development of Acoustic Sounder (SODAR) in India as an Upgraded Technology for Environmental Protection: A Review

Sound Detection and Ranging (SODAR) has moved to the forefront of consumer technology due to the pressing need toengage the Atmospheric Boundary Layer (ABL) in environmental protection. An active ground-based remote sensingsystem (SODAR) is used to determine the lower-atmosphere wind profile and temperature structure. SODAR can detectturbulence parameters in the ABL from a distance and can be used for wind profiling. SODAR, with its significantlyenhanced capability, is expected to be a futuristic remote sensing device with several uses in the near future. Including anemphasis on its applications and current developments, this article examines SODAR's early history, with a review of Indianstudies. The article examines past breakthroughs in SODAR as well as its advancement and applications, with an emphasison India due to the worldwide nature of SODAR research. Additionally, the article discusses how effective SODAR is inprotecting the environment and how important it is going forward. After summarising the applications, various opportunitiesand barriers incurred in SODAR use, a proposed review article to provide insights into previously understudied, unstudied,and studied research work accomplished on SODAR in India is constructed. The article accentuates the role of SODAR asan environmental safeguarding tool

Ubiquitous Superconducting Diode Effect in Superconductor Thin Films

The macroscopic coherence in superconductors supports dissipationless supercurrents which could play a central role in emerging quantum technologies. Accomplishing unequal supercurrents in the forward and backward directions would enable unprecedented functionalities. This nonreciprocity of critical supercurrents is called superconducting (SC) diode effect. We demonstrate strong SC diode effect in conventional SC thin films, such as niobium and vanadium, employing external magnetic fields as small as 1 Oe. Interfacing the SC layer with a ferromagnetic semiconductor EuS, we further accomplish non-volatile SC diode effect reaching a giant efficiency of 65%. By careful control experiments and theoretical modeling, we demonstrate that the critical supercurrent nonreciprocity in SC thin films could be easily accomplished with asymmetrical vortex edge/surface barriers and the universal Meissner screening current governing the critical currents. Our engineering of the SC diode effect in simple systems opens door for novel technologies. Meanwhile, we reveal the ubiquity of Meissner screening effect induced SC diode effect in superconducting films, which should be eliminated with great care in the search of exotic superconducting states harboring finite-momentum Cooper pairing.Comment: 27 pages, 16 figure

Steroid regulation: An overlooked aspect of tolerance and chronic rejection in kidney transplantation.

Steroid conversion (HSD11B1, HSD11B2, H6PD) and receptor genes (NR3C1, NR3C2) were examined in kidney-transplant recipients with "operational tolerance" and chronic rejection (CR), independently and within the context of 88 tolerance-associated genes. Associations with cellular types were explored. Peripheral whole-blood gene-expression levels (RT-qPCR-based) and cell counts were adjusted for immunosuppressant drug intake. Tolerant (n = 17), stable (n = 190) and CR patients (n = 37) were compared. Healthy controls (n = 14) were used as reference. The anti-inflammatory glucocorticoid receptor (NR3C1) and the cortisol-activating HSD11B1 and H6PD genes were up-regulated in CR and were lowest in tolerant patients. The pro-inflammatory mineralocorticoid gene (NR3C2) was downregulated in stable and CR patients. NR3C1 was associated with neutrophils and NR3C2 with T-cells. Steroid conversion and receptor genes, alone, enabled classification of tolerant patients and were major contributors to gene-expression signatures of both, tolerance and CR, alongside known tolerance-associated genes, revealing a key role of steroid regulation and response in kidney transplantation