Revalidation of Natrix clerki Wall, 1925, an overlooked species in the genus Amphiesma Dumeril, Bibron & Dumeril, 1854 (Squamata: Natricidae)

Natrix clerki Wall, 1925, previously known from its sole holotype and considered a synonym of Amphiesma parallelum (Boulenger, 1890), is resurrected in the genus Amphiesma on the basis of the analysis of morphological variation in 28 specimens of ``Amphiesma parallelum'' auctorum, plus six living, unvouchered specimens discovered in Arunachal Pradesh and Nagaland, India, and one vouchered specimen from Talle Valley in Arunachal Pradesh. Specimens from northeast India (Nagaland), northern Myanmar, and China (Yunnan), previously identified as Amphiesma parallelum either in the literature or in museum's catalogues, are also here referred to A. clerki. The holotype of Amphiesma clerki is redescribed. As a consequence, the definition of Amphiesma parallelum is modified. A. parallelum inhabits the Khasi Hills and Naga Hills in Northeast India, whereas A. clerki has a wider range in the Eastern Himalayas, northern Myanmar and Yunnan (China). Amphiesma clerki differs from A. parallelum by its longer tail, dorsal scales more strongly keeled, scales of the first dorsal scale row strongly keeled vs. smooth, a postocular streak not interrupted at the level of the neck, and a much more vivid pattern on a darker background colour. Characters of species of the Amphiesma parallelum group, i.e. A. clerki, A. parallelum, A. bitaeniatum, A. platyceps and A. sieboldii are compared. A key to this group is provided.

Structure and Conformation of an Antidepressant Drug, Nitroxazepine Hydrochloride Monohydrate

CIsH20N3Oa+.C1-.H2 O, M r = 395, orthorhombic, Pn21a, a = 7.710 (4), b = 11.455 (3), c -- 21.199 (3)/k, Z = 4, V = 1872.4/k 3, D m = 1.38, D C = 1.403 g cm -3, F(000) = 832, g(Cu Kct) = 20.94 cm -l. Intensities for 1641 reflections were measured on a Nonius CAD-4 diffractometer; of these, 1470 were significant. The structure was solved by direct methods and refined to an R index of 0.045 using a blockdiagonal least-squares procedure. The angle between the least-squares planes through the benzene rings is 125.0 (5) ° and the side chain is folded similarly to one of the independent molecules of imipramine hydrochloride.

Structure and conformation of an anti-depressant drug, nitroxazepine hydrochloride monohydrate

CIsH20N3Oa+.C1-.H2 O, M r = 395, orthorhombic, Pn21a, a = 7.710 (4), b = 11.455 (3), c -- 21.199 (3)/k, Z = 4, V = 1872.4/k 3, D m = 1.38, D C = 1.403 g cm -3, F(000) = 832, g(Cu Kct) = 20.94 cm -l. Intensities for 1641 reflections were measured on a Nonius CAD-4 diffractometer; of these, 1470 were significant. The structure was solved by direct methods and refined to an R index of 0.045 using a blockdiagonal least-squares procedure. The angle between the least-squares planes through the benzene rings is 125.0 (5) ° and the side chain is folded similarly to one of the independent molecules of imipramine hydrochloride.

Surface Ligand Population Controlled Oriented Attachment: A Case of CdS Nanowires

using two types of organic ligands having similar chemical structure but different physical properties and varying their dynamic population at the surface of zinc blende seed nanocrystals, self-assembled zinc blende semicircular-shaped bent nanowires of CdS are synthesized via a colloidal synthetic approach. It is found that the hydrophobic tail interaction of long-chain ligands puts strain on these thin nanowires (< 2 nm diameter) and bend them to some extent, forming strained nanowires.

Synthesis of Diversified Thioethers,1-Aroylalkylisoquinolin-1-yl Thioethers, by Electrophilic S-Alkylation of 3-Phenyl Isoquinoline-1(2H)-thione

A mild and efficient method for the synthesis of thioethers has been developed. The 3-phenylisoquinoline-1(2H)-thione underwent S-alkylation to afford structurally diverse sulfides in high yield.

A Theory of the Lifted Temperature Minimum on Calm Clear Nights

Numerous reports from several parts of the world have confirmed that on calm clear nights a minimum in air temperature can occur just above ground, at heights of the order of $\frac{1}{2}$ m or less. This phenomenon, first observed by Ramdas & Atmanathan (1932), carries the associated paradox of an apparently unstable layer that sustains itself for several hours, and has not so far been satisfactorily explained. We formulate here a theory that considers energy balance between radiation, conduction and free or forced convection in humid air, with surface temperature, humidity and wind incorporated into an appropriate mathematical model as parameters. A complete numerical solution of the coupled air-soil problem is used to validate an approach that specifies the surface temperature boundary condition through a cooling rate parameter. Utilizing a flux-emissivity scheme for computing radiative transfer, the model is numerically solved for various values of turbulent friction velocity. It is shown that a lifted minimum is predicted by the model for values of ground emissivity not too close to unity, and for sufficiently low surface cooling rates and eddy transport. Agreement with observation for reasonable values of the parameters is demonstrated. A heuristic argument is offered to show that radiation substantially increases the critical Rayleigh number for convection, thus circumventing or weakening Rayleigh-Benard instability. The model highlights the key role played by two parameters generally ignored in explanations of the phenomenon, namely surface emissivity and soil thermal conductivity, and shows that it is unnecessary to invoke the presence of such particulate constituents as haze to produce a lifted minimum.

The energy balance in the Ramdas layer

On calm clear nights, air at a height of a few decimetres above bare soil can be cooler than the surface by several degrees in what we shall call the Ramdas layer (Ramdas and Atmanathan, 1932). The authors have recently offered a logical explanation for such a lifted temperature minimum, together with a detailed numerical model. In this paper, we provide physical insight into the phenomenon by a detailed discussion of the energy budget in four typical cases, including one with a lifted minimum. It is shown that the net cooling rate near ground is the small difference between two dominant terms, representing respectively radiative upflux from the ground and from the air layers just above ground. The delicate energy balance that leads to the lifted minimum is upset by turbulent transport, by surface emissivity approaching unity, or by high ground cooling rates. The rapid variation of the flux emissivity of humid air is shown to dominate radiative transport near the ground.

Probing the role of the fully conserved Cys126 in triosephosphate isomerase by site-specific mutagenesis - distal effects on dimer stability

Cys126 is a completely conserved residue in triosephosphate isomerase that is proximal to the active site but has been ascribed no specific role in catalysis. A previous study of the C126S and C126A mutants of yeast TIM reported substantial catalytic activity for the mutant enzymes, leading to the suggestion that this residue is implicated in folding and stability [Gonzalez-Mondragon E et al. (2004) Biochemistry43, 3255–3263]. We re-examined the role of Cys126 with the Plasmodium falciparum enzyme as a model. Five mutants, C126S, C126A, C126V, C126M, and C126T, were characterized. Crystal structures of the 3-phosphoglycolate-bound C126S mutant and the unliganded forms of the C126S and C126A mutants were determined at a resolution of 1.7–2.1 Å. Kinetic studies revealed an approximately five-fold drop in kcat for the C126S and C126A mutants, whereas an approximately 10-fold drop was observed for the other three mutants. At ambient temperature, the wild-type enzyme and all five mutants showed no concentration dependence of activity. At higher temperatures (> 40 °C), the mutants showed a significant concentration dependence, with a dramatic loss in activity below 15 μm. The mutants also had diminished thermal stability at low concentration, as monitored by far-UV CD. These results suggest that Cys126 contributes to the stability of the dimer interface through a network of interactions involving His95, Glu97, and Arg98, which form direct contacts across the dimer interface.

Probing the role of the fully conserved Cys126 in triosephosphate isomerase by site-specific mutagenesis - distal effects on dimer stability

DatabaseStructural data are available in the Protein Data Bank under the accession numbers 3PVF, 3PY2, and 3PWA. Structured digital abstract Tim binds to Tim by x-ray crystallography (View interaction).

Ising pyrochlore magnets: Low-temperature properties, "ice rules," and beyond

Pyrochlore magnets are candidates for what Harris et al. [Phys. Rev. Lett. 79, 2554 (1997)] call "spin-ice" behavior. We present theoretical simulations of relevance for the pyrochlore family R2Ti2O7 (R = rare earth) supported by magnetothermal measurements on selected systems. Ey considering long-ranged dipole-dipole as well as short-ranged superexchange interactions, we get three distinct behaviors: (i) an ordered doubly degenerate state, (ii) a highly disordered state with a broad transition to paramagnetism, and (iii) a partially ordered state with a sharp transition to paramagnetism. Closely corresponding behavior is seen in the real compounds.

Nonlinear Optical Properties of Stacked Conjugated Systems

We study linear and nonlinear optical properties of two push-pull polyenes stacked in head to head (HtH) and head to tail (HtT) configurations, at different stacking angles within the Pariser-Parr-Pople model using exact diagonalization method. By varying the stacking angle between the polyenes, we find that the optical gap varies marginally, but transition dipoles show large variations. We find that the dominant first-order hyperpolarizability component beta(XXX) for HtH arrangement and beta(YYY) for HtT arrangement strongly depend on the distance of separation between molecules, while the other smaller component beta(XYY) for HtH arrangement and beta(XXY) for HtT arrangement) does not show this variation with distance. We find that the beta(XXX) for HtH configuration shows a maximum at an angle away from 0, in contrast with the oriented gas model. This angle varies with distance between the polyenes, and at large distance it falls to 0. The ratio of all components of beta of a dimer to monomer is less than two for HtH configuration for all angles. But for HtT configurations the ratio of the dominant beta component is greater than two at large angles. Our ZINDO study on two monomers (4-hydroxy-4'-nitroazobenzene) connected in a nonconjugative fashion shows a linear increase in vertical bar(beta) over right arrow (av)vertical bar without much red shift in optical gap. There is a linear increase in vertical bar(beta) over right arrow (av)vertical bar with increase in number of monomers connected nonconjugatively without resulting in a red shift in optical gap.

An Accurate Fractional Period Delay Generation System

An all-digital technique is proposed for generating an accurate delay irrespective of the inaccuracies of a controllable delay line. A subsampling technique-based delay measurement unit (DMU) capable of measuring delays accurately for the full period range is used as the feedback element to build accurate fractional period delays based on input digital control bits. The proposed delay generation system periodically measures and corrects the error and maintains it at the minimum value without requiring any special calibration phase. Up to 40x improvement in accuracy is demonstrated for a commercial programmable delay generator chip. The time-precision trade-off feature of the DMU is utilized to reduce the locking time. Loop dynamics are adjusted to stabilize the delay after the minimum error is achieved, thus avoiding additional jitter. Measurement results from a high-end oscilloscope also validate the effectiveness of the proposed system in improving accuracy.

Seismic intensity map of South India for estimated future earthquakes

In this study, an attempt has been made to prepare the seismic intensity map for south India considering the probable earthquakes in the region. Anbazhagan et al. (Nat Hazards 60:1325-1345, 2012) have identified eight probable future earthquake zones in south India based on rupture-based seismic hazard analysis. Anbazhagan et al. (Eng Geol 171:81-95, 2014) has estimated the maximum future earthquake magnitude at these eight zones using regional rupture character. In this study, the whole south India is divided into several grids of size 1(o) x 1(o) and the intensity at each grid point is calculated using the regional intensity model for the maximum earthquake magnitude at each of the eight zones. The intensity due to earthquakes at these zones is mapped and thus eight seismic intensity maps are prepared. The final seismic intensity map of south India is obtained by considering the maximum intensity at each grid point due to the estimated earthquakes. By looking at the seismic intensity map, one can expect slight to heavy damage due to the probable earthquake magnitudes. Heavy damage may happen close to the probable earthquake zones.