3,882 research outputs found
Isospin effects on the mass dependence of balance energy
We study the effect of isospin degree of freedom on balance energy throughout
the mass range between 50 and 350 for two sets of isotopic systems with N/Z =
1.16 and 1.33 as well as isobaric systems with N/Z = 1.0 and 1.4. Our findings
indicate that different values of balance energy for two isobaric systems may
be mainly due to the Coulomb repulsion. We also demonstrate clearly the
dominance of Coulomb repulsion over symmetry energy.Comment: 5 pages, 3 figures In this version the discussion is in terms of N/Z
whereas in the journal the whole discussion is in terms of N/A. The
conclusions remain unaffecte
Thermodynamic behaviour of two-dimensional vesicles revisited
We study pressurised self-avoiding ring polymers in two dimensions using
Monte Carlo simulations, scaling arguments and Flory-type theories, through
models which generalise the model of Leibler, Singh and Fisher [Phys. Rev.
Lett. Vol. 59, 1989 (1987)]. We demonstrate the existence of a thermodynamic
phase transition at a non-zero scaled pressure , where , with the number of monomers and the pressure
, keeping constant, in a class of such models.
This transition is driven by bond energetics and can be either continuous or
discontinuous. It can be interpreted as a shape transition in which the ring
polymer takes the shape, above the critical pressure, of a regular N-gon whose
sides scale smoothly with pressure, while staying unfaceted below this critical
pressure. In the general case, we argue that the transition is replaced by a
sharp crossover. The area, however, scales with for all positive in
all such models, consistent with earlier scaling theories.Comment: 6 pages, 4 figures, EPL forma
Knowledge of Maternal and Newborn Care Among Primary Level Health Workers in Kapilvastu District of Nepal
Background: Higher maternal and neonatal deaths are common in low‑ and middle‑income countries; due to less access to skilled help. Adequate knowledge and skills on maternal and newborn care (MNC) of community health workers can improve maternal and newborn health.Aims: To identify the knowledge of primary level health workers on some components of MNC.Subjects and Methods: Respondents were selected using simple random sampling method. For collecting the data, enumerators visited health institutions for 2 months from 1|st October to 31st November 2012, and structured interview schedule was used to gather the information. A cross‑sectional study was conducted in a total of one hundred and thirty‑seven primary level health workers in Kapilvastu district, Nepal. The Chi‑square test was employed to examine the association between the knowledge of health workers on MNC and designation and work experience. Data were analyzed using SPSS version 17.Results: In a total of 137 primary level health workers, more than half 53.2% (73/137) were senior auxiliary health workers/health assistant. Health workers having correct knowledge on contents of MNC were‑registration 32.1% (44/137), major components of antenatal care 57.7% (79/137), danger signs of pregnancy 39.4% (54/137), five cleans 59.1% (81/137), postnatal health problems 54.0% (74/137), majority to health action to newborn care, newborn bath and meaning of exclusive breastfeeding. There was a statistical association between designation of health workers and above‑mentioned components of MNC (P < 0.05).Conclusions: The differentials in the knowledge of MNC among primary level health suggest improving knowledge of the grass root level health workers with appropriate training and development programs.Keywords: Knowledge, Maternal and newborn care, Primary level health worker
Universality Class of the Reversible-Irreversible Transition in Sheared Suspensions
Collections of non-Brownian particles suspended in a viscous fluid and
subjected to oscillatory shear at very low Reynolds number have recently been
shown to exhibit a remarkable dynamical phase transition separating reversible
from irreversible behaviour as the strain amplitude or volume fraction are
increased. We present a simple model for this phenomenon, based on which we
argue that this transition lies in the universality class of the conserved DP
models or, equivalently, the Manna model. This leads to predictions for the
scaling behaviour of a large number of experimental observables. Non-Brownian
suspensions under oscillatory shear may thus constitute the first experimental
realization of an inactive-active phase transition which is not in the
universality class of conventional directed percolation.Comment: 4 pages, 2 figures, final versio
Strong and weak hydrogen bonds in the protein-ligand interface
The characteristics of NH···O, OH···O, and CH···O hydrogen bonds and other weak intermolecular interactions are analyzed in a large and diverse group of 251 protein-ligand complexes using a new computer program that was developed in-house for this purpose. The interactions examined in the present study are those which occur in the active sites, defined here as a sphere of 10 Å radius around the ligand. Notably, NH···O and OH···O bonds tend towards linearity. Multifurcated interactions are especially common, especially multifurcated acceptors, and the average degree of furcation is 2.6 hydrogen bonds per furcated acceptor. A significant aspect of this study is that we have been able to assess the reliability of hydrogen bond geometry as a function of crystallographic resolution. Thresholds of 2.3 and 2.0 Å are established for strong and weak hydrogen bonds, below which hydrogen bond geometries may be safely considered for detailed analysis. Interactions involving water as donor or acceptor, and CH···O bonds with Gly and Tyr as donors are ubiquitous in the active site. A similar trend was observed in an external test set of 233 protein-ligand complexes belonging to the kinase family. Weaker interactions like XH···∏ (X = C, N, O) and those involving halogen atoms as electrophiles or nucleophiles have also been studied. We conclude that the strong and weak hydrogen bonds are ubiquitous in protein-ligand recognition, and that with suitable computational tools very large numbers of strong and weak intermolecular interactions in the ligand-protein interface may be analyzed reliably. Results confirm earlier trends reported previously by us but the extended nature of the present data set mean that the observed trends are more reliable
Strong and weak hydrogen bonds in drug-DNA complexes: a statistical analysis
A statistical analysis of strong and weak hydrogen bonds in the minor groove of DNA was carried out for a set of 70 drug-DNA complexes. The terms "strong" and "weak" pertain to the inherent strengths and weakness of the donor and acceptor fragments rather than to any energy considerations. The dataset was extracted from the protein data bank (PDB). The analysis was performed with an in-house software, hydrogen bond analysis tool (HBAT). In addition to strong hydrogen bonds such as O-H···O and N-H···O, the ubiquitous presence of weak hydrogen bonds such as C-H···O is implicated in molecular recognition. On an average, there are 1.4 weak hydrogen bonds for every strong hydrogen bond. For both categories of interaction, the N(3) of purine and the O(2) of pyrimidine are favoured acceptors. Donor multifurcation is common with the donors generally present in the drug molecules, and shared by hydrogen bond acceptors in the minor groove. Bifurcation and trifurcation are most commonly observed. The metrics for strong hydrogen bonds are consistent with established trends. The geometries are variable for weak hydrogen bonds. A database of recognition geometries for 26 literature amidinium-based inhibitors of Human African Trypanosomes (HAT) was generated with a docking study using seven inhibitors which occur in published crystal structures included in the list of 70 complexes mentioned above, and 19 inhibitors for which the drug-DNA complex crystal structures are unknown. The virtual geometries so generated correlate well with published activities for these 26 inhibitors, justifying our assumption that strong and weak hydrogen bonds are optimized in the active site
Design of Blast Resistant Structure
A shock blast resistant structure designed, developed and experimentally evaluated by the authors is described. We structure, capable of with standing dynamic loading (12 psi and a static pressure of 1.5 m earth cover) due to blast or any other explosion, also gives protection against radiation, chemical and thermal hazards. Some results and details of analysis and experimentation are presented
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