991 research outputs found
Laparoscopy-Assisted Resection of Tailgut Cysts: Report of a Case
Tailgut cysts, or retrorectal cystic hamartomas, are rare congenital developmental lesions, most commonly located in the retrorectal space, and are more common in women. We present a case of retrorectal tailgut cyst managed using a laparoscopic approach. A 36-year-old woman presented with incidentally detected retrorectal tumors during evaluation for a gallbladder polyp. Her past medical history revealed that she had undergone cesarean section twice. The tumor marker CA 19-9 level was 42.52 U/ml. CT of the pelvis with contrast and pelvic MRI revealed a 3.9 × 3.3 cm well-defined, homogeneous cystic mass in the right presacral area, and a 2.5 × 1.5 cm cystic mass in the precoccygeal space. The patient underwent laparoscopic exploration with a preoperative diagnosis of tailgut cysts based on radiological findings. The operative time was 90 min including 30 min of subsequent laparoscopic cholecystectomy without placement of additional trocars. The surgical specimens consisted of two fragments of fibrofatty tissues, unilocular cystic masses. The final pathologic diagnosis was tailgut cysts with no evidence of malignancy. Postoperative recovery was uneventful, and the patient was discharged after 3 days. In conclusion, surgical resection is recommended in the management of retrorectal tailgut cyst to establish a definite diagnosis and to rule out malignancy. The laparoscopic approach is a feasible and safe option
Correlates of physical activity level among hemodialysis patients in Selangor, Malaysia.
INTRODUCTION: There is mounting evidence demonstrating the importance of adequate physical activity to promote better well-being among hemodialysis patients. Available data pertaining to the levels of physical activity and its determinants among hemodialysis patients is, however, scarce in Malaysia. The objectives of this study are hence to determine the levels of physical activity and it associated factors among hemodialysis patients.
METHODOLOGY: A total of 70 subjects were recruited from three dialysis centres in Selangor. A face-to-face interview was conducted to obtain socio-demographic data and subjects' knowledge on dietary sources. Medical history, biochemical parameters and weight status were obtained from medical records. Physical activity level (PAL) was assessed using the Global Physical Activity Questionnaire (GPAQ). RESULTS: A total of 81.4% and 18.6% of the respondents had low and moderate PALs, respectively. Thus, none of the respondents had high PAL. Serum creatinine, education level, personal income and knowledge score on potassium-related medical complications were factors found to correlate significantly with PAL. Multiple linear regression analysis showed that higher PAL was predicted by a lower knowledge score on dietary sodium source, higher education and higher serum creatinine.
CONCLUSION: Despite consistent documentation of the potential positive impact of physical exercise on hemodialysis outcomes, the level of physical activity remains low among these patients. It is hoped that these findings can add to the existing body of knowledge and serve as a supporting document for the formulation of appropriate interventions to improve the status of physical activity among hemodialysis patients in Malaysia
Evolutionary minority game with heterogeneous strategy distribution
We present detailed numerical results for a modified form of the so-called
Minority Game, which provides a simplified model of a competitive market. Each
agent has a limited set of strategies, and competes to be in a minority. An
evolutionary rule for strategy modification is included to mimic simple
learning. The results can be understood by considering crowd formation within
the population.Comment: Revtex file + 4 figure
Minimal Mass Matrices for Dirac Neutrinos
We consider the possibility of neutrinos being Dirac particles and study
minimal mass matrices with as much zero entries as possible. We find that up to
5 zero entries are allowed. Those matrices predict one vanishing mass state, CP
conservation and U_{e3} either zero or proportional to R, where R is the ratio
of the solar and atmospheric \Delta m^2. Matrices containing 4 zeros can be
classified in categories predicting U_{e3} = 0, U_{e3} \neq 0 but no CP
violation or |U_{e3}| \neq 0 and possible CP violation. Some cases allow to set
constraints on the neutrino masses. The characteristic value of U_{e3} capable
of distinguishing some of the cases with non-trivial phenomenological
consequences is about R/2 \sin 2 \theta_{12}. Matrices containing 3 and less
zero entries imply (with a few exceptions) no correlation for the observables.
We outline models leading to the textures based on the Froggatt-Nielsen
mechanism or the non-Abelian discrete symmetry D_4 \times Z_2.Comment: 32 pages, 3 figures. Comments and references added. To appear in JHE
Influence of poly(ethelene glycol) on the phase behaviour of sodium dodecyl sulfate/1-pentanol/water systems.
The phase behavior of SDS/1-pentanol/water system in the presence of poly(ethylene glycol), PEG, was determined at 27.0 ± 0.5°C. The addition of PEGs, namely, mPEG2000, mPEG8000 and PEG5000, changes both the isotropic and liquid crystalline phases indicating the presence of surfactant-polymer interaction in the system, respectively. The increase of polymer chain length and content in the system decreases both the isotropic and liquid crystalline regions. It is believed that the absence of methyl group in the mPEG goes through different surfactant-polymer conformation as the change in isotropic region is different between mPEG(2000 and 8000) and PEG5000. The presence of polymers (mPEG2000, mPEG8000, and PEG5000) in the isotropic solution along 90:10 of SDS:1-pentanol tie-line changes the packing and orientation of micelle
Dynamics of fluctuations in a fluid below the onset of Rayleigh-B\'enard convection
We present experimental data and their theoretical interpretation for the
decay rates of temperature fluctuations in a thin layer of a fluid heated from
below and confined between parallel horizontal plates. The measurements were
made with the mean temperature of the layer corresponding to the critical
isochore of sulfur hexafluoride above but near the critical point where
fluctuations are exceptionally strong. They cover a wide range of temperature
gradients below the onset of Rayleigh-B\'enard convection, and span wave
numbers on both sides of the critical value for this onset. The decay rates
were determined from experimental shadowgraph images of the fluctuations at
several camera exposure times. We present a theoretical expression for an
exposure-time-dependent structure factor which is needed for the data analysis.
As the onset of convection is approached, the data reveal the critical
slowing-down associated with the bifurcation. Theoretical predictions for the
decay rates as a function of the wave number and temperature gradient are
presented and compared with the experimental data. Quantitative agreement is
obtained if allowance is made for some uncertainty in the small spacing between
the plates, and when an empirical estimate is employed for the influence of
symmetric deviations from the Oberbeck-Boussinesq approximation which are to be
expected in a fluid with its density at the mean temperature located on the
critical isochore.Comment: 13 pages, 10 figures, 52 reference
Molecularly imprinted polymer based on MWCNTs-QDs as fluorescent biomimetic sensor for specific recognition of target protein
A novel molecularly imprinted optosensing material based on multi-walled carbon nanotube-quantum dots (MWCNT-QDs) has been designed and synthesized for its high selectivity, sensitivity and specificity in the recognition of a target protein bovine serum albumin (BSA). Molecularly imprinted polymer coated MWCNT-QDs using BSA as the template (BMIP-coated MWCNT-QDs) exhibits a fast mass-transfer speed with a response time of 25 min. It is found that the BSA as a target protein can significantly quench the luminescence of BMIP-coated MWCNT-QDs in a concentration-dependent manner that is best described by a Stem-Volmer equation. The K-SV for BSA is much higher than bovine hemoglobin and lysozyme, implying a highly selective recognition of the BMIP-coated MWCNT-QDs to BSA. Under optimal conditions, the relative fluorescence intensity of BMIP-coated MWCNT-QDs decreases linearly with the increasing target protein BSA in the concentration range of 5.0 x 10(-7)-35.0 x 10(-7) M with a detection limit of 80 nM
The Similarity Hypothesis in General Relativity
Self-similar models are important in general relativity and other fundamental
theories. In this paper we shall discuss the ``similarity hypothesis'', which
asserts that under a variety of physical circumstances solutions of these
theories will naturally evolve to a self-similar form. We will find there is
good evidence for this in the context of both spatially homogenous and
inhomogeneous cosmological models, although in some cases the self-similar
model is only an intermediate attractor. There are also a wide variety of
situations, including critical pheneomena, in which spherically symmetric
models tend towards self-similarity. However, this does not happen in all cases
and it is it is important to understand the prerequisites for the conjecture.Comment: to be submitted to Gen. Rel. Gra
Phantom Divide Crossing with General Non-minimal Kinetic Coupling
We propose a model of dark energy consists of a single scalar field with a
general non-minimal kinetic couplings to itself and to the curvature. We study
the cosmological dynamics of the equation of state in this setup. The coupling
terms have the form and
where
and are coupling parameters and their dimensions depend on the type
of function . We obtain the conditions required for phantom divide
crossing and show numerically that a cosmological model with general
non-minimal derivative coupling to the scalar and Ricci curvatures can realize
such a crossing.Comment: 12 pages, 4 figures. Accepted for publication in Gen. Rel. Grav.
arXiv admin note: substantial text overlap with arXiv:1105.4967,
arXiv:1201.1627, and with arXiv:astro-ph/0610092 by other author
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