175 research outputs found
Ab initio determination of ion-traps in silver-doped chalcogenide glass
We present a microscopic picture of silver dynamics in GeSe:Ag glass
obtained from {\it ab initio} simulation. The dynamics of Ag is explored at two
temperatures, 300K and 700K. In the relaxed network, Ag occupies bond centers
between suitably separated host sites. At 700K, Ag motion proceeds via a
trapping-release dynamics, between "super traps" or cages consisting of
multiple bond-center sites in a small volume. Our work offers a first
principles identification of trapping centers invoked in current theories, with
a description of their properties. We compute the charge state of the Ag in the
network, and show that it is neutral if weakly bonded and Ag if in a
trapping center.Comment: submitted to pr
A review of strategies to improve rational prescribing in asthma.
Background: There are well-recognised gaps between evidence-based recommendations and prescribing practices in asthma. While different strategies have been devised to improve rational prescribing, the impact of these is uncertain. Aim: To examine the characteristics and effectiveness of strategies to improve rational prescribing in asthma. Method: We systematically searched electronic databases to find studies that reported on strategies to improve prescribing in asthma, or included rational prescribing as one of the main components of the program. Results: There were thirteen relevant studies. All of the strategies described in these studies involved physician education using a variety of modalities; two of the trials also included patient-specific prescribing direction. Twelve of thirteen studies reported improved prescribing practice. There was significant heterogeneity in the interventions and outcome criteria employed by the studies. Conclusion: Strategies to improve rational prescribing in asthma show promise, but the significant methodological heterogeneity, and the absence in most cases of demonstrable clinical benefit, raise concerns about their applicability in clinical practice. Keywords: asthma, inappropriate prescribing, medication therapy management, physician's practice patterns, quality improvemen
Ab initio determination of ion-traps in silver-doped chalcogenide glass
We present a microscopic picture of silver dynamics in GeSe:Ag glass
obtained from {\it ab initio} simulation. The dynamics of Ag is explored at two
temperatures, 300K and 700K. In the relaxed network, Ag occupies bond centers
between suitably separated host sites. At 700K, Ag motion proceeds via a
trapping-release dynamics, between "super traps" or cages consisting of
multiple bond-center sites in a small volume. Our work offers a first
principles identification of trapping centers invoked in current theories, with
a description of their properties. We compute the charge state of the Ag in the
network, and show that it is neutral if weakly bonded and Ag if in a
trapping center.Comment: submitted to pr
Maximum Penetration Height and Intrusion Speed of Weak Symmetric Plane Fountains in Linearly Stratified Fluids
The flow behavior of weak symmetric plane fountains in linearly stratified fluids is studied numerically with three-dimensional simulations over a range of the Froude ((Formula presented.)), Reynolds ((Formula presented.)), and stratification numbers (s). The two main parameters describing the fountain characterization are the dimensionless maximum fountain penetration height ((Formula presented.)) and intrusion velocity ((Formula presented.)), which differ significantly at different flow development stages. It was found that the stratification stabilizes the symmetry of the weak fountains, which makes the fountain become asymmetric at a larger (Formula presented.) value, and (Formula presented.) at the fully developed stage continues to increase as a result of the intrusion, which continually changes the ambient fluid stratification features, thus the buoyant force. The evolution of intrusion experiences three distinct stages. Both (Formula presented.) and s have effects on (Formula presented.) and (Formula presented.), with the effect of (Formula presented.) usually larger than that of s. The overall impacts of (Formula presented.) and s can be quantified in terms of (Formula presented.), with a and b varying for different parameters. With numerical results, empirical correlations are produced in terms of (Formula presented.) for each relevant parameter, which generally predict the results very well
ASSESSMENT OF LEVEL OF BLOOD GLUCOSE IN TYPE-2 DIABETIC PATIENTS UNDERGOING DENTAL TREATMENTS
Aims and objectives: The main objective of the study is to analyze the level of blood glucose in type-2 diabetic patients undergoing dental treatments. Material and methods: This cross sectional study was conducted in THQ Hospital, Haveli Lakhan during March 2018 to November 2018. The data was collected from 100 diabetic patients who undergo dental procedures and treatments. Venous blood sample was collected from each patient and then centrifuged this sample for the separation of serum. The sample included only the patients who presented blood glucose levels and HbA1c demonstrating that diabetes was under control. They should also be under continuous oral hypoglycemic drugs treatment, medical supervision and no dose alterations. Results: The data was collected from 100 diabetic patients. There is no statistically significant difference between the groups, regarding the evaluation period (p> 0.05). For heart rate, there was no statistically significant difference between the groups regarding the evaluation period (p> 0.05). However, regarding the comparison between the periods statistically significant differences were observed (p <0.05) for the T1 and T2 values for group. However, when comparing the periods statistically significant differences were observed (p <0.05) for T2 and T3 values for group. Conclusion: It is concluded that periodontal disease is the main oral clinical manifestation in diabetic patients
A semi-quantitative scattering theory of amorphous materials
It is argued that topological disorder in amorphous solids can be described
by local strains related to local reference crystals and local rotations. An
intuitive localization criterion is formulated from this point of view. The
Inverse Participation Ratio and the location of mobility edges in band tails is
directly related to the character of the disorder potential in amorphous solid,
the coordination number, the transition integral and the nodes of wave
functions of the corresponding reference crystal. The dependence of the decay
rate of band tails on temperature and static disorder are derived. \textit{Ab
initio} simulations on a-Si and experiments on a-Si:H are compared to these
predictions.Comment: 4 pages, 2 figures, will be submitted to Phys. Rev. Let
A large spin-up rate measured with INTEGRAL in the High Mass X-ray Binary Pulsar SAXJ2103.5+4545
The High Mass X-ray Binary Pulsar SAXJ2103.5+4545 has been observed with
INTEGRAL several times during the last outburst in 2002-2004. We report a
comprehensive study of all INTEGRAL observations, allowing a study of the pulse
period evolution during the recent outburst. We measured a very rapid spin-up
episode, lasting 130days, which decreased the pulse period by 1.8s. The spin-up
rate, pdot=-1.5e-7 s/s, is the largest ever measured for SAXJ2103.5+4545, and
it is among the fastest for an accreting pulsar. The pulse profile shows
evidence for temporal variability, apparently not related to the source flux or
to the orbital phase. The X-ray spectrum is hard and there is significant
emission up to 150keV. A new derivation of the orbital period, based on RXTE
data, is also reported.Comment: 8 pages, 7 figures, accepted for publication in A&
Probing stellar winds and accretion physics in high-mass X-ray binaries and ultra-luminous X-ray sources with LOFT
This is a White Paper in support of the mission concept of the Large
Observatory for X-ray Timing (LOFT), proposed as a medium-sized ESA mission. We
discuss the potential of LOFT for the study of high-mass X-ray binaries and
ultra-luminous X-ray sources. For a summary, we refer to the paper.Comment: White Paper in Support of the Mission Concept of the Large
Observatory for X-ray Timing. (v2 few typos corrected
Is there a highly magnetized neutron star in GX 301-2?
We present the results of an in-depth study of the long-period X-ray pulsar
GX 301-2. Using archival data of INTEGRAL, RXTE ASM, and CGRO BATSE, we study
the spectral and timing properties of the source. Comparison of our timing
results with previously published work reveals a secular decay of the orbital
period at a rate of \simeq -3.25 \times 10^{-5} d yr^{-1}, which is an order of
magnitude faster than for other known systems. We argue that this is probably
result either of the apsidal motion or of gravitational coupling of the matter
lost by the optical companion with the neutron star, although current
observations do not allow us to distinguish between those possibilities. We
also propose a model to explain the observed long pulse period. We find that a
very strong magnetic field B \sim 10^{14} G can explain the observed pulse
period in the framework of existing models for torques affecting the neutron
star. We show that the apparent contradiction with the magnetic field strength
B_{CRSF} \sim 4 \times 10^{12} G derived from the observed cyclotron line
position may be resolved if the line formation region resides in a tall
accretion column of height \sim 2.5 - 3 R_{NS}. The color temperature measured
from the spectrum suggests that such a column may indeed be present, and our
estimates show that its height is sufficient to explain the observed cyclotron
line position.Comment: 10 pages, 7 figures, accepted for publication in Astronomy and
Astrophysics. Referee comments are implemented
Synthesis and Characterization of Silver-Coated Polymeric Scaffolds for Bone Tissue Engineering: Antibacterial and In Vitro Evaluation of Cytotoxicity and Biocompatibility
In bone tissue engineering, multifunctional composite materials are very challenging. Bone tissue engineering is an innovative technique to develop biocompatible scaffolds with suitable orthopedic applications with enhanced antibacterial and mechanical properties. This research introduces a polymeric nanocomposite scaffold based on arabinoxylan-co-acrylic acid, nano-hydroxyapatite (nHAp), nano-aluminum oxide (nAl₂O₃), and graphene oxide (GO) by free-radical polymerization for the development of porous scaffolds using the freeze-drying technique. These polymeric nanocomposite scaffolds were coated with silver (Ag) nanoparticles to improve antibacterial activities. Together, nHAp, nAl₂O₃, and GO enhance the multifunctional properties of materials, which regulate their physicochemical and biomechanical properties. Results revealed that the Ag-coated polymeric nanocomposite scaffolds had excellent antibacterial properties and better microstructural properties. Regulated morphological properties and maximal antibacterial inhibition zones were found in the porous scaffolds with the increasing amount of GO. Moreover, the nanosystem and the polymeric matrix have improved the compressive strength (18.89 MPa) and Young’s modulus (198.61 MPa) of scaffolds upon increasing the amount of GO. The biological activities of the scaffolds were investigated against the mouse preosteoblast cell lines (MC3T3-E1) and increasing the quantities of GO helps cell adherence and proliferation. Therefore, our findings showed that these silver-coated polymeric nanocomposite scaffolds have the potential for engineering bone tissue
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