299 research outputs found
DESIGN AND EVALUATION OF FOOD GRADE WAX MATRIX SUSTAINED RELEASE MINI-TABLETS OF MONTELUKAST SODIUM
Objective: The objective of this study is to formulate a tablet that fits in the size range of mini-tablets using wax matrix forming substances, allowsvariation of drug dose and study of drug release kinetics of the dosage form.Methods: The blends of drug with glyceryl monostearate, purified rice bran wax and carnauba wax that renders the waxes food grade, were preparedand evaluated for precompression characteristics. The blends were compressed into mini-tablets having desirable physical characteristics andwere subjected to tests such as weight variation and friability. The tablets were subjected to drug dissolution test and the release parameters weremathematically treated for order and mechanism of drug release.Results: The tablets complied with the pharmacopoeial standards of physical characteristics. The release was satisfactorily sustained (up to 10 hrs)by carnauba wax and rice bran wax, but not by glyceryl monostearate (only up to 4 hrs). The release followed a zero order with super Case II transportbeing the major mechanism of drug release.Conclusion: Wax matrix formers were satisfactorily used for sustained drug release mini-tablets. The tablets had good physical characteristics withmajor mechanism of drug release being super Case II transport.Keywords: Wax matrix, Sustained release, Mini-tablets, Montelukast sodium
Facilitating return to work through early specialist health-based interventions (FRESH): protocol for a feasibility randomised controlled trial
Background
Over one million people sustain traumatic brain injury each year in the UK and more than 10 % of these are moderate or severe injuries, resulting in cognitive and psychological problems that affect the ability to work. Returning to work is a primary rehabilitation goal but fewer than half of traumatic brain injury survivors achieve this. Work is a recognised health service outcome, yet UK service provision varies widely and there is little robust evidence to inform rehabilitation practice. A single-centre cohort comparison suggested better work outcomes may be achieved through early occupational therapy targeted at job retention. This study aims to determine whether this intervention can be delivered in three new trauma centres and to conduct a feasibility, randomised controlled trial to determine whether its effects and cost effectiveness can be measured to inform a definitive trial.
Methods/design
Mixed methods study, including feasibility randomised controlled trial, embedded qualitative studies and feasibility economic evaluation will recruit 102 people with traumatic brain injury and their nominated carers from three English UK National Health Service (NHS) trauma centres. Participants will be randomised to receive either usual NHS rehabilitation or usual rehabilitation plus early specialist traumatic brain injury vocational rehabilitation delivered by an occupational therapist. The primary objective is to assess the feasibility of conducting a definitive trial; secondary objectives include measurement of protocol integrity (inclusion/exclusion criteria, intervention adherence, reasons for non-adherence) recruitment rate, the proportion of eligible patients recruited, reasons for non-recruitment, spectrum of TBI severity, proportion of and reasons for loss to follow-up, completeness of data collection, gains in face-to-face Vs postal data collection and the most appropriate methods of measuring primary outcomes (return to work, retention) to determine the sample size for a larger trial.
Discussion
To our knowledge, this is the first feasibility randomised controlled trial of a vocational rehabilitation health intervention specific to traumatic brain injury. The results will inform the design of a definitive trial
STM Spectroscopy of ultra-flat graphene on hexagonal boron nitride
Graphene has demonstrated great promise for future electronics technology as
well as fundamental physics applications because of its linear energy-momentum
dispersion relations which cross at the Dirac point. However, accessing the
physics of the low density region at the Dirac point has been difficult because
of the presence of disorder which leaves the graphene with local microscopic
electron and hole puddles, resulting in a finite density of carriers even at
the charge neutrality point. Efforts have been made to reduce the disorder by
suspending graphene, leading to fabrication challenges and delicate devices
which make local spectroscopic measurements difficult. Recently, it has been
shown that placing graphene on hexagonal boron nitride (hBN) yields improved
device performance. In this letter, we use scanning tunneling microscopy to
show that graphene conforms to hBN, as evidenced by the presence of Moire
patterns in the topographic images. However, contrary to recent predictions,
this conformation does not lead to a sizable band gap due to the misalignment
of the lattices. Moreover, local spectroscopy measurements demonstrate that the
electron-hole charge fluctuations are reduced by two orders of magnitude as
compared to those on silicon oxide. This leads to charge fluctuations which are
as small as in suspended graphene, opening up Dirac point physics to more
diverse experiments than are possible on freestanding devices.Comment: Nature Materials advance online publication 13/02/201
The nature of localization in graphene under quantum Hall conditions
Particle localization is an essential ingredient in quantum Hall physics
[1,2]. In conventional high mobility two-dimensional electron systems Coulomb
interactions were shown to compete with disorder and to play a central role in
particle localization [3]. Here we address the nature of localization in
graphene where the carrier mobility, quantifying the disorder, is two to four
orders of magnitude smaller [4,5,6,7,8,9,10]. We image the electronic density
of states and the localized state spectrum of a graphene flake in the quantum
Hall regime with a scanning single electron transistor [11]. Our microscopic
approach provides direct insight into the nature of localization. Surprisingly,
despite strong disorder, our findings indicate that localization in graphene is
not dominated by single particle physics, but rather by a competition between
the underlying disorder potential and the repulsive Coulomb interaction
responsible for screening.Comment: 18 pages, including 5 figure
Multi-modality curative treatment of salivary gland cancer liver metastases with drug-eluting bead chemoembolization, radiofrequency ablation, and surgical resection: a case report
<p>Abstract</p> <p>Introduction</p> <p>Liver metastases are rare in salivary gland tumors and have been reported only once to be the first manifestation of the disease. They are usually treated with surgical resection of the primary tumor and systemic chemotherapy. Drug-eluting bead chemoembolization has an evolving role in the treatment of hepatocellular carcinoma, as well as in the treatment of metastatic disease of the liver. Nevertheless, it has never been used in a patient with salivary gland liver metastases.</p> <p>Case presentation</p> <p>We report a case of a 51-year-old Caucasian Greek woman who presented to our hospital with liver metastases as the first manifestation of an adenoid cystic carcinoma of the left submandibular gland. The liver lesions were deemed inoperable because of their size and multi-focality and proved resistant to systemic chemotherapy. She was curatively treated with a combination of doxorubicin eluting bead (DC Beads) chemoembolization, intra-operative and percutaneous radiofrequency ablation, and radiofrequency-assisted surgical resection. The patient remained disease-free one year after the surgical resection.</p> <p>Conclusion</p> <p>In conclusion, this complex case is an example of inoperable liver metastatic disease from the salivary glands that was refractory to systemic chemotherapy but was curatively treated with a combination of locoregional therapies and surgery. A multi-disciplinary approach and the adoption of modern radiological techniques produced good results after conventional therapies failed and there were no other available treatment modalities.</p
Inflation and dark matter in two Higgs doublet models
We consider the Higgs inflation in the extension of the Standard Model with
two Higgs doublets coupled to gravity non-minimally. In the presence of an
approximate global U(1) symmetry in the Higgs sector, both radial and angular
modes of neutral Higgs bosons drive inflation where large non-Gaussianity is
possible from appropriate initial conditions on the angular mode. We also
discuss the case with single-field inflation for which the U(1) symmetry is
broken to a Z_2 subgroup. We show that inflationary constraints, perturbativity
and stability conditions restrict the parameter space of the Higgs quartic
couplings at low energy in both multi- and single-field cases. Focusing on the
inert doublet models where Z_2 symmetry remains unbroken at low energy, we show
that the extra neutral Higgs boson can be a dark matter candidate consistent
with the inflationary constraints. The doublet dark matter is always heavy in
multi-field inflation while it can be light due to the suppression of the
co-annihilation in single-field inflation. The implication of the extra quartic
couplings on the vacuum stability bound is also discussed in the light of the
recent LHC limits on the Higgs mass.Comment: (v1) 28 pages, 8 figures; (v2) 29 pages, a new subsection 3.3 added,
references added and typos corrected, to appear in Journal of High Energy
Physic
Subjective Well-being in Rural India: The Curse of Conspicuous Consumption
Using data on 697 individuals from 375 rural low income households in India, we test expectations on the effects of relative income and conspicuous consumption on subjective well-being. The results of the multi-level regression analyses show that individuals who spent more on conspicuous consumption report lower levels of subjective well-being. Surprisingly an individual’s relative income position does not affect feelings of well-being. Motivated by positional concerns, people do not passively accept their relative rank but instead consume conspicuous goods to keep up with the Joneses. Conspicuous consumption always comes at the account of the consumption of basic needs. Our analyses point at a positional treadmill effect of the consumption of status goods
Evolution of Microscopic Localization in Graphene in a Magnetic Field from Scattering Resonances to Quantum Dots
Graphene is a unique two-dimensional material with rich new physics and great
promise for applications in electronic devices. Physical phenomena such as the
half-integer quantum Hall effect and high carrier mobility are critically
dependent on interactions with impurities/substrates and localization of Dirac
fermions in realistic devices. We microscopically study these interactions
using scanning tunneling spectroscopy (STS) of exfoliated graphene on a SiO2
substrate in an applied magnetic field. The magnetic field strongly affects the
electronic behavior of the graphene; the states condense into welldefined
Landau levels with a dramatic change in the character of localization. In zero
magnetic field, we detect weakly localized states created by the substrate
induced disorder potential. In strong magnetic field, the two-dimensional
electron gas breaks into a network of interacting quantum dots formed at the
potential hills and valleys of the disorder potential. Our results demonstrate
how graphene properties are perturbed by the disorder potential; a finding that
is essential for both the physics and applications of graphene.Comment: to be published in Nature Physic
Clostridium difficile Infections amongst Patients with Haematological Malignancies: A Data Linkage Study
OBJECTIVES: Identify risk factors for Clostridium difficile infection (CDI) and assess CDI outcomes among Australian patients with a haematological malignancy. METHODS: A retrospective cohort study involving all patients admitted to hospitals in Western Australia with a haematological malignancy from July 2011 to June 2012. Hospital admission data were linked with all hospital investigated CDI case data. Potential risk factors were assessed by logistic regression. The risk of death within 60 and 90 days of CDI was assessed by Cox Proportional Hazards regression. RESULTS: There were 2085 patients of whom 65 had at least one CDI. Twenty percent of CDI cases were either community-acquired, indeterminate source or had only single-day admissions in the 28 days prior to CDI. Using logistic regression, having acute lymphocytic leukaemia, neutropenia and having had bacterial pneumonia or another bacterial infection were associated with CDI. CDI was associated with an increased risk of death within 60 and 90 days post CDI, but only two deaths had CDI recorded as an antecedent factor. Ribotyping information was available for 33 of the 65 CDIs. There were 19 different ribotypes identified. CONCLUSIONS: Neutropenia was strongly associated with CDI. While having CDI is a risk factor for death, in many cases it may not be a direct contributor to death but may reflect patients having higher morbidity. A wide variety of C. difficile ribotypes were found and community-acquired infection may be under-estimated in these patients
- …