1,231 research outputs found
Multiservice capacity and interference statistics of the uplink of high altitude platforms (HAPs) for asynchronous and synchronous WCDMA system
In this work, the capacity and the interference statistics of the uplink of high-altitude platforms (HAPs) for asynchronous and synchronous WCDMA system assuming finite transmission power and imperfect power control are studied. Propagation loss used to calculate the received signal power is due to the distance, shadowing, and wall insertion loss. The uplink capacity for 3- and 3.75-G services is given for different cell radius assuming outdoor and indoor voice users only, data users only and a combination of the two services. For 37 macrocells HAP, the total uplink capacity is 3,034 outdoor voice users or 444 outdoor data users. When one or more than one user is an indoor user, the uplink capacity is 2,923 voice users or 444 data users when the walls entry loss is 10 dB. It is shown that the effect of the adjacent channels interference is very small
Giant Cell Arteritis Presenting as Small Bowel Infarction
Giant cell arteritis predominantly affects cranial arteries and rarely involves other sites. We report a patient who presented with small bowel obstruction because of infarction from mesenteric giant cell arteritis. She had an unusual cause of her obstruction and a rare manifestation of giant cell arteritis. In spite of aggressive therapy with steroids, she died a month later because of multiple complications. We discuss the diagnosis and management of small bowel obstruction and differential diagnosis of vasculitis of the gastrointestinal tract. We were able to find 11 cases of bowel involvement with giant cell arteritis in the English literature. This case report illustrates that giant cell arteritis can be a cause of small bowel obstruction and bowel infarction. In the proper clinical setting, vasculitides need to be considered early in the differential diagnosis when therapy may be most effective
Effect of goal-directed haemodynamic therapy on postoperative complications in low-moderate risk surgical patients: a multicentre randomised controlled trial (FEDORA trial)
Background
The aim of this study was to evaluate postoperative complications in patients having major elective surgery using oesophageal Doppler monitor-guided goal-directed haemodynamic therapy (GDHT), in which administration of fluids, inotropes, and vasopressors was guided by stroke volume, mean arterial pressure, and cardiac index.
Methods
The FEDORA trial was a prospective, multicentre, randomised, parallel-group, controlled patient- and observer-blind trial conducted in adults scheduled for major elective surgery. Randomization and allocation were carried out by a central computer system. In the control group, intraoperative fluids were given based on traditional principles. In the GDHT group, the intraoperative goals were to maintain a maximal stroke volume, with mean arterial pressure >70 mm Hg, and cardiac index âĽ2.5 litres minâ1 mâ2. The primary outcome was percentage of patients with moderate or severe postoperative complications during the first 180 days after surgery.
Results
In total, 450 patients were randomized to the GDHT group (n=224) or control group (n=226). Data from 420 subjects were analysed. There were significantly fewer with complications in the GDHT group (8.6% vs 16.6%, P=0.018). There were also fewer complications (acute kidney disease, pulmonary oedema, respiratory distress syndrome, wound infections, etc.), and length of hospital stay was shorter in the GDHT group. There was no significant difference in mortality between groups.
Conclusions
Oesophageal Doppler monitor-guided GDHT reduced postoperative complications and hospital length of stay in lowâmoderate risk patients undergoing intermediate risk surgery, with no difference in mortality at 180 days
Vitamin B12 deficiency in metformin-treated type-2 diabetes patients, prevalence and association with peripheral neuropathy
BACKGROUND : The association between long-term metformin use and low vitamin B12 levels has been proven.
However, the prevalence estimates of metformin-induced vitamin B12 deficiency showed considerable variation
among the studies. The potential of the deficiency to cause or worsen peripheral neuropathy in type-2 diabetes
mellitus (T2DM) patients has been investigated with conflicting results. The aim of the study was to investigate:
1) the prevalence of vitamin B12 deficiency in T2DM patients on metformin; 2) the association between vitamin B12
and peripheral neuropathy; 3) and the risk factors for vitamin B12 deficiency in these patients.
METHODS : In this cross-sectional study, consecutive metformin-treated T2DM patients attending diabetes clinics of
two public hospitals in South Africa were approached for participation. Participation included measuring vitamin
B12 levels and assessing peripheral neuropathy using Neuropathy Total Symptom Score-6 (NTSS-6) questionnaire.
The prevalence of vitamin B12 deficiency (defined by concentrations <150 pmol/L) was determined. Those with
NTSS-6 scores >6 were considered to have peripheral neuropathy. The relationship between vitamin B12 and
peripheral neuropathy was investigated when the two variables were in the binary and continuous forms. Multiple
logistic regression was used to determine risk factors for vitamin B12 deficiency.
RESULTS : Among 121 participants, the prevalence of vitamin B12 deficiency was 28.1 %. There was no difference in
presence of neuropathy between those with normal and deficient vitamin levels (36.8 % vs. 32.3 %, P = 0.209).
Vitamin B12 levels and NTSS-6 scores were not correlated (Spearmanâs rho =0.056, P = 0.54). HbA1c (mmol/mol)
(OR = 0.97, 95 % CI: 0.95 to 0.99, P = 0.003) and black race (OR = 0.34, 95 % CI: 0.13 to 0.92, P = 0.033) were risk
factors significantly associated with vitamin B12 deficiency. Metformin daily dose (gram) showed borderline
significance (OR = 1.96, 95 % CI: 0.99 to 3.88, P = 0.053).
CONCLUSIONS : Close to third of metformin-treated T2DM patients had vitamin B12 deficiency. The deficiency was
not associated with peripheral neuropathy. Black race was a protective factor for vitamin B12 deficiency.The Department of Pharmacology, University of Pretoriahttp://bmcpharmacoltoxicol.biomedcentral.comam2017Internal MedicinePharmacolog
Insulin Resistance in Chileans of European and Indigenous Descent: Evidence for an Ethnicity x Environment Interaction
<p><b>Background:</b> Effects of urbanisation on diabetes risk appear to be greater in indigenous populations worldwide than in populations of European origin, but the reasons are unclear. This cross-sectional study aimed to determine whether the effects of environment (Rural vs. Urban), adiposity, fitness and lifestyle variables on insulin resistance differed between individuals of indigenous Mapuche origin compared to those of European origin in Chile.</p>
<p><b>Methodology/Principal Findings:</b> 123 Rural Mapuche, 124 Urban Mapuche, 91 Rural European and 134 Urban European Chilean adults had blood taken for determination of HOMA-estimated insulin resistance (HOMA(IR)) and underwent assessment of physical activity/sedentary behaviour (using accelerometry), cardiorespiratory fitness, dietary intake and body composition. General linear models were used to determine interactions with ethnicity for key variables. There was a significant "ethnicity x environment" interaction for HOMA(IR) (Mean +/- SD; Rural Mapuche: 1.65 +/- 2.03, Urban Mapuche: 4.90 +/- 3.05, Rural European: 0.82 +/- 0.61, Urban European: 1.55 +/- 1.34, p((interaction)) = 0.0003), such that the effect of urbanisation on HOMA(IR) was greater in Mapuches than Europeans. In addition, there were significant interactions (all p<0.004) with ethnicity for effects of adiposity, sedentary time and physical activity on HOMA(IR), with greater effects seen in Mapuches compared to Europeans, an observation that persisted after adjustment for potential confounders.</p>
<p><b>Conclusions/Significance:</b> Urbanisation, adiposity, physical activity and sedentary behaviour influence insulin resistance to a greater extent in Chilean Mapuches than Chileans of European descent. These findings have implications for the design and implementation of lifestyle strategies to reduce metabolic risk in different ethnic groups, and for understanding of the mechanisms underpinning human insulin resistance.</p>
Chronic Nicotine Modifies Skeletal Muscle Na,K-ATPase Activity through Its Interaction with the Nicotinic Acetylcholine Receptor and Phospholemman
Our previous finding that the muscle nicotinic acetylcholine receptor (nAChR) and the Na,K-ATPase interact as a regulatory complex to modulate Na,K-ATPase activity suggested that chronic, circulating nicotine may alter this interaction, with long-term changes in the membrane potential. To test this hypothesis, we chronically exposed rats to nicotine delivered orally for 21â31 days. Chronic nicotine produced a steady membrane depolarization of âź3 mV in the diaphragm muscle, which resulted from a net change in electrogenic transport by the Na,K-ATPase Îą2 and Îą1 isoforms. Electrogenic transport by the Îą2 isoform increased (+1.8 mV) while the activity of the Îą1 isoform decreased (â4.4 mV). Protein expression of Na,K-ATPase Îą1 or Îą2 isoforms and the nAChR did not change; however, the content of Îą2 subunit in the plasma membrane decreased by 25%, indicating that its stimulated electrogenic transport is due to an increase in specific activity. The physical association between the nAChR, the Na,K-ATPase Îą1 or Îą2 subunits, and the regulatory subunit of the Na,K-ATPase, phospholemman (PLM), measured by co-immuno precipitation, was stable and unchanged. Chronic nicotine treatment activated PKCÎą/β2 and PKCδ and was accompanied by parallel increases in PLM phosphorylation at Ser63 and Ser68. Collectively, these results demonstrate that nicotine at chronic doses, acting through the nAChR-Na,K-ATPase complex, is able to modulate Na,K-ATPase activity in an isoform-specific manner and that the regulatory range includes both stimulation and inhibition of enzyme activity. Cholinergic modulation of Na,K-ATPase activity is achieved, in part, through activation of PKC and phosphorylation of PLM
Cholinesterase Inhibitors and Hospitalization for Bradycardia: A Population-Based Study
Laura Park-Wyllie and colleagues examined the health records of more than 1.4 million older adults and show that initiation of cholinesterase inhibitor therapy is associated with a more than doubling of the risk of hospitalization for bradycardia
Study of decays to the final state and evidence for the decay
A study of decays is performed for the first time
using data corresponding to an integrated luminosity of 3.0
collected by the LHCb experiment in collisions at centre-of-mass energies
of and TeV. Evidence for the decay
is reported with a significance of 4.0 standard deviations, resulting in the
measurement of
to
be .
Here denotes a branching fraction while and
are the production cross-sections for and mesons.
An indication of weak annihilation is found for the region
, with a significance of
2.4 standard deviations.Comment: All figures and tables, along with any supplementary material and
additional information, are available at
https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2016-022.html,
link to supplemental material inserted in the reference
Study of DJ meson decays to D+Ďâ, D0Ď+ and Dâ+Ďâ final states in pp collisions
A study of D+Ďâ, D0Ď+ and Dâ+Ďâ final states is performed using pp collision data, corresponding to an integrated luminosity of 1.0 fbâ1, collected at a centre-of-mass energy of 7 TeV with the LHCb detector. The D1(2420)0 resonance is observed in the Dâ+Ďâ final state and the Dâ2(2460) resonance is observed in the D+Ďâ, D0Ď+ and Dâ+Ďâ final states. For both resonances, their properties and spin-parity assignments are obtained. In addition, two natural parity and two unnatural parity resonances are observed in the mass region between 2500 and 2800 MeV. Further structures in the region around 3000 MeV are observed in all the Dâ+Ďâ, D+Ďâ and D0Ď+ final states
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
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