4,710 research outputs found
How do Doctors Decide When to Prescribe Antibiotics in Upper Respiratory Tract Infections?
Purpose: To examine the predictive features which doctors use when prescribing antibiotics in upper respiratory tract infections (URTIs). Method: This is a cross sectional, prospective study done in a teaching university primary care centre in Kuala Lumpur from June to August 2000. Twelve primary care practitioners participated in the study. Each practitioner was asked to record clinical data and prescriptions given to twenty consecutive patients with URTIs using a structured questionnaire for each patient
Numerical comparison between Maxwell stress method and equivalent multipole approach for calculation of the dielectrophoretic force in octupolar cell traps
This work presents detailed numerical calculations of the dielectrophoretic force in octupolar traps designed for single-cell trapping. A trap with eight planar electrodes is studied for spherical and ellipsoidal particles using an indirect implementation of the boundary element method (BEM). Multipolar approximations of orders one to three are compared with the full Maxwell stress tensor (MST) calculation of the electrical force on spherical particles. Ellipsoidal particles are also studied, but in their case only the dipolar approximation is available for comparison with the MST solution. The results show that the full MST calculation is only required in the study of non-spherical particles.Singapore-MIT Alliance (SMA
A Comparison Of The Performances Of Various Single Variable Charts.
Control charts are used for process monitoring and improvement in industries. Two charts are usually used in the monitoring of both the mean and variance separately
Respiratory dysfunction in myotonic dystrophy type 1: A systematic review
Myotonic dystrophy type 1 (DM1) is one of the most common muscular dystrophies in adults. This review summarises the current literature regarding the natural history of respiratory dysfunction in DM1, the role of central respiratory drive and peripheral respiratory muscle involvement and its significance in respiratory function, and investigates the relationship between genetics (CTG repeat length) and respiratory dysfunction. The review included all articles that reported spirometry on 10 or more myotonic dystrophy patients. The final review included 55 articles between 1964 and 2017. The major conclusions of this review were (1) confirmation of the current consensus that respiratory dysfunction, predominantly a restrictive ventilatory pattern, is common in myotonic dystrophy and is associated with alveolar hypoventilation, chronic hypercapnia, and sleep disturbance in the form of sleep apnoea and sleep related disordered breathing; (2) contrary to commonly held belief, there is no consensus in the literature regarding the relationship between CTG repeat length and severity of respiratory dysfunction and a relationship has not been established; (3) the natural history and time-course of respiratory functional decline is very poorly understood in the current literature; (4) there is a consensus that there is a significant involvement of central respiratory drive in this alveolar hypoventilation however the current literature does not identify the mechanism for this
Guide to transverse projections and mass-constraining variables
This paper seeks to demonstrate that many of the existing mass-measurement
variables proposed for hadron colliders (mT, mEff, mT2, missing pT, hT,
rootsHatMin, etc.) are far more closely related to each other than is widely
appreciated, and indeed can all be viewed as a common mass bound specialized
for a variety of purposes. A consequence of this is that one may understand
better the strengths and weaknesses of each variable, and the circumstances in
which each can be used to best effect. In order to achieve this, we find it
necessary first to revisit the seemingly empty and infertile wilderness
populated by the subscript "T" (as in pT) in order to remind ourselves what
this process of transversification actually means. We note that, far from being
simple, transversification can mean quite different things to different people.
Those readers who manage to battle through the barrage of transverse notation
distinguishing mass-preserving projections from velocity preserving
projections, and `early projection' from `late projection', will find their
efforts rewarded towards the end of the paper with (i) a better understanding
of how collider mass variables fit together, (ii) an appreciation of how these
variables could be generalized to search for things more complicated than
supersymmetry, (iii) will depart with an aversion to thoughtless or naive use
of the so-called `transverse' methods of any of the popular computer
Lorentz-vector libraries, and (iv) will take care in their subsequent papers to
be explicit about which of the 61 identified variants of the `transverse mass'
they are employing.Comment: 47 pages, 15 figures. v2: Title change for journal, and minor
typographical correction
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S-nitrosylation of endogenous protein tyrosine phosphatases in endothelial insulin signaling.
Nitric oxide (NO) exerts its biological function through S-nitrosylation of cellular proteins. Due to the labile nature of this modification under physiological condition, identification of S-nitrosylated residue in enzymes involved in signaling regulation remains technically challenging. The present study investigated whether intrinsic NO produced in endothelium-derived MS-1 cells response to insulin stimulation might target endogenous protein tyrosine phosphatases (PTPs). For this, we have developed an approach using a synthetic reagent that introduces a phenylacetamidyl moiety on S-nitrosylated Cys, followed by detection with anti-phenylacetamidyl Cys (PAC) antibody. Coupling with sequential blocking of free thiols with multiple iodoacetyl-based Cys-reactive chemicals, we employed this PAC-switch method to show that endogenous SHP-2 and PTP1B were S-nitrosylated in MS-1 cells exposed to insulin. The mass spectrometry detected a phenylacetamidyl moiety specifically present on the active-site Cys463 of SHP-2. Focusing on the regulatory role of PTP1B, we showed S-nitrosylation to be the principal Cys reversible redox modification in endothelial insulin signaling. The PAC-switch method in an imaging format illustrated that a pool of S-nitrosylated PTP1B was colocalized with activated insulin receptor to the cell periphery, and that such event was endothelial NO synthase (eNOS)-dependent. Moreover, ectopic expression of the C215S mutant of PTP1B that mimics the active-site Cys215 S-nitrosylated form restored insulin responsiveness in eNOS-ablated cells, which was otherwise insensitive to insulin stimulation. This work not only introduces a new method that explores the role of physiological NO in regulating signal transduction, but also highlights a positive NO effect on promoting insulin responsiveness through S-nitrosylation of PTP1B's active-site Cys215
Tunable magnetic response of metamaterials
We demonstrate a thermally tunable optical metamaterial with negative
permeability working in the visible range. By covering coupled metallic
nanostrips with aligned nematic liquid crystals (NLCs), the magnetic response
wavelength of the metamaterial is effectively tuned through control of the
ambient temperature, changing the refractive index of LC via phase transitions.
By increasing the ambient temperature from 20 degree to 50 degree, the magnetic
response wavelength shifts from 650nm to 632nm. Numerical simulations confirm
our tests and match the experimental observations well
Graphic Organizer in Action: Solving Secondary Mathematics Word Problems
Mathematics word problems are one of the most challenging topics to learn and teach in secondary schools. This is especially the case in countries where English is not the first language for the majority of the people, such as in Brunei Darussalam. Researchers proclaimed that limited language proficiency and limited Mathematics strategies are the possible causes to this problem. However, whatever the reason is behind difficulties students face in solving Mathematical word problems, it is perhaps the teaching and learning of the Mathematics that need to be modified. For example, the use of four-square-and-a-diamond graphic organizer that infuses model drawing skill; and Polya\u27s problem solving principles, to solve Mathematical word problems may be some of the strategies that can help in improving students\u27 word problem solving skills. This study, through quantitative analysis found that the use of graphic organizer improved students\u27 performance in terms of Mathematical knowledge, Mathematical strategy and Mathematical explanation in solving word problems. Further qualitative analysis revealed that the use of graphic organizer boosted students\u27 confidence level and positive attitudes towards solving word problems
Boron Nitride Monolayer: A Strain-Tunable Nanosensor
The influence of triaxial in-plane strain on the electronic properties of a
hexagonal boron-nitride sheet is investigated using density functional theory.
Different from graphene, the triaxial strain localizes the molecular orbitals
of the boron-nitride flake in its center depending on the direction of the
applied strain. The proposed technique for localizing the molecular orbitals
that are close to the Fermi level in the center of boron nitride flakes can be
used to actualize engineered nanosensors, for instance, to selectively detect
gas molecules. We show that the central part of the strained flake adsorbs
polar molecules more strongly as compared with an unstrained sheet.Comment: 20 pages, 9 figure
Widely Tunable Berry curvature in the Magnetic Semimetal Cr1+dTe2
Magnetic semimetals have increasingly emerged as lucrative platforms hosting
spin-based topological phenomena in real and momentum spaces. Of particular
interest is the emergence of Berry curvature, whose geometric origin,
accessibility from Hall transport experiments, and material tunability, bodes
well for new physics and practical devices. Cr1+dTe2, a self-intercalated
magnetic transition metal dichalcogenide, TMD, exhibits attractive natural
attributes relevant to such applications, including topological magnetism,
tunable electron filling, magnetic frustration etc. While recent studies have
explored real-space Berry curvature effects in this material, similar
considerations of momentum-space Berry curvature are lacking. Here, we
systematically investigate the electronic structure and transport properties of
epitaxial Cr1+dTe2 thin films over a wide range of doping, d between 0.33 and
0.71. Spectroscopic experiments reveal the presence of a characteristic
semi-metallic band region near the Brillouin Zone edge, which shows a rigid
band like energy shift as a function of d. Transport experiments show that the
intrinsic component of the anomalous Hall effect, AHE, is sizable, and
undergoes a sign flip across d. Finally, density functional theory calculations
establish a causal link between the observed doping evolution of the band
structure and AHE: the AHE sign flip is shown to emerge from the sign change of
the Berry curvature, as the semi-metallic band region crosses the Fermi energy.
Our findings underscore the increasing relevance of momentum-space Berry
curvature in magnetic TMDs and provide a unique platform for intertwining
topological physics in real and momentum spaces
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