314 research outputs found
Ischaemic strokes in patients with pulmonary arteriovenous malformations and hereditary hemorrhagic telangiectasia: associations with iron deficiency and platelets.
<div><p>Background</p><p>Pulmonary first pass filtration of particles marginally exceeding ∼7 µm (the size of a red blood cell) is used routinely in diagnostics, and allows cellular aggregates forming or entering the circulation in the preceding cardiac cycle to lodge safely in pulmonary capillaries/arterioles. Pulmonary arteriovenous malformations compromise capillary bed filtration, and are commonly associated with ischaemic stroke. Cohorts with CT-scan evident malformations associated with the highest contrast echocardiographic shunt grades are known to be at higher stroke risk. Our goal was to identify within this broad grouping, which patients were at higher risk of stroke.</p><p>Methodology</p><p>497 consecutive patients with CT-proven pulmonary arteriovenous malformations due to hereditary haemorrhagic telangiectasia were studied. Relationships with radiologically-confirmed clinical ischaemic stroke were examined using logistic regression, receiver operating characteristic analyses, and platelet studies.</p><p>Principal Findings</p><p>Sixty-one individuals (12.3%) had acute, non-iatrogenic ischaemic clinical strokes at a median age of 52 (IQR 41–63) years. In crude and age-adjusted logistic regression, stroke risk was associated not with venous thromboemboli or conventional neurovascular risk factors, but with low serum iron (adjusted odds ratio 0.96 [95% confidence intervals 0.92, 1.00]), and more weakly with low oxygen saturations reflecting a larger right-to-left shunt (adjusted OR 0.96 [0.92, 1.01]). For the same pulmonary arteriovenous malformations, the stroke risk would approximately double with serum iron 6 µmol/L compared to mid-normal range (7–27 µmol/L). Platelet studies confirmed overlooked data that iron deficiency is associated with exuberant platelet aggregation to serotonin (5HT), correcting following iron treatment. By MANOVA, adjusting for participant and 5HT, iron or ferritin explained 14% of the variance in log-transformed aggregation-rate (p = 0.039/p = 0.021).</p><p>Significance</p><p>These data suggest that patients with compromised pulmonary capillary filtration due to pulmonary arteriovenous malformations are at increased risk of ischaemic stroke if they are iron deficient, and that mechanisms are likely to include enhanced aggregation of circulating platelets.</p></div
Multiphysics Analysis of a Magnetorheological Damper
A Magnetorheological damping has evolved as a potential tool in vibration control. The design of magnetorheological damping involves analysis of fluid flow principles and electromagnetic flux analysis. This research paper involves design and analysis of a magnetorheological damper employed for vibration control. The analysis is carried over by considering the domain as an axisymmetric model. The damping force of the damper depends upon the shear stress due to fluid viscosity and yield stress induced due to magnetic flux applied. The damping force generated by the damper is calculated
Estimating process capability index Cpm using a bootstrap sequential sampling procedure
Construction of a confidence interval for process capability index CPM is often based on a normal approximation with fixed sample size. In this article, we describe a different approach in constructing a fixed-width confidence interval for process capability index CPM with a preassigned accuracy by using a combination of bootstrap and sequential sampling schemes. The optimal sample size required to achieve a preassigned confidence level is obtained using both two-stage and modified two-stage sequential procedures. The procedure developed is also validated using an extensive simulation study.<br /
Exploring the cause of conduction delays in patients with repaired Tetralogy of Fallot
Aim Cardiac dyssynchrony in patients with repaired Tetralogy of Fallot (rToF) has been attributed to right bundle branch block (RBBB), fibrosis and/or the patches that are inserted during repair surgery. We aimed to investigate the basis of abnormal activation in rToF patients by mapping the electrical activation sequence during sinus rhythm (SR) and right ventricular (RV) pacing.Methods and Results A total of 17 patients were studied [13 with rToF, 2 with left bundle branch block (LBBB), and 2 without RBBB or LBBB (non-BBB)] during medically indicated cardiac surgery. During SR and RV pacing, measurements were performed using 112-electrode RV endocardial balloons (rToF only) and biventricular epicardial sock arrays (four of the rToF and all non-rToF patients). During SR, functional lines of block occurred in five rToF patients, while RV pacing caused functional blocks in four rToF patients. The line of block persisted during both SR and RV pacing in only 2 out of 13 rToF patients. Compared to SR, RV pacing increased dispersion of septal activation, but not dispersion of endocardial and epicardial activation of the RV free wall. During pacing, RV and left ventricular activation dispersion in rToF patients were comparable to that of the non-rToF patients.Conclusion The results of the present study indicate that the delayed activation in the right ventricle of rToF patients is predominantly due to block(s) in the Purkinje system and that conduction in RV tissue is fairly normal
High Performance Pre-computation based Self-Controlled Precharge-Free Content-Addressable Memory
Content-addressable memory (CAM) is a special type of memory used in networking applications for very-high-speed searching operation. It compares input search data with the table of stored data, and returns the address of matching data in a parallel search method. Also the use of parallel comparison results in reduced search time, it also significantly increases power consumption when compared to precharge based CAM. The low-power NAND-type and high-speed NOR-type CAM methods require the precharge prior to the search. This PF phase leads to increase the settling time of the output and also reduce the speed of the search operation. In this paper, a High performance Pre-computation Based Self-Controlled Precharge-Free CAM (PB-SCPF CAM) structure is proposed for high-speed applications which reduce the settling time as well as improve the speed of the search. Where search time is very important for designing larger word lengths, SCPF architecture is efficacious in applications. The experimental results show that PB-SCPF approach can attain on average 32% in power reduction and 80% in delay reduction. The most important contribution of this project is that it offers theoretical and practical proofs to verify that our suggested PB-SCPF CAM system can achieve greater power reduction without the requirement of special CAM cell design. This shows that the approach which we have used is more flexible and adaptive for general designs and high speed applications
Heavy metal characterisation in surface sediments off southeast coast of India: Implication on marine pollution
1810-1818The present study investigated heavy metals (Mn, Cr, Cu, Ni, Pb, and Zn) distribution in the surface sediments off Karaikal – Velankanni offshore along the east coast of Bay of Bengal as an indicator of marine pollution during 2004-2005. The sediments were analyzed for sand, silt, clay ratio, CaCO3, organic matter, and heavy metal (Mn, Cr, Cu, Ni, Pb, and Zn) contents. The contamination factor (CF) values for the heavy metals are found to be in the order: Mn >Cr >Ni >Zn >Cu >Pb during August 2004; and during January 2005 the CF values were found to be in the order: Zn >Mn >Cu >Ni >Pb >Cr. Zn contamination was found to be low to moderate. 10 samples were found with low and moderate Mn contamination. All the samples displayed moderate contamination with Cu, Ni, and Pb. Among the selected sediments, those which are collected from Karaikal and Velankanni shore were found to be highly contaminated by heavy elements due to the discharge of effluents from petrochemical, oil spills, port activity, and shipping activities. The occurrence of a wide range of elements in coastal sediments is mainly related to the textural variability of sediments during 2004 and 2005
Reinserting Physiology into Cardiac Mapping Using Omnipolar Electrograms
Omnipolar electrograms (EGMs) make use of biophysical electric fields that accompany activation along the surface of the myocardium. A grid-like electrode array provides bipolar signals in orthogonal directions to deliver catheter-orientation-independent assessments of cardiac electrophysiology. Studies with myocyte monolayers, isolated animal and human hearts, and anesthetized animals validated the tenets of omnipolar EGMs. The combination of information from omnipolar-based activation vectors and voltages may aid in localizing areas of scar, lesion gaps, wavefront disorganization, and fractionation or collision during arrhythmias. The goal of omnipolar EGMs is to better characterize myocardium through reintroducing electrogram direction related fundamentals of cardiac electrophysiology.S
A Precise Review on the Pharmacognostical and Pharmacological Imputes of Bermuda Grass: Cynodon Dactylon Linn
The World Health Organization estimates that about 80% of the world\u27s population uses herbs to meet their basic healthcare needs. Cynodon Dactylon (Doob grass), is a sacred grass belongs to the Poaceae family. It is a weed and has been found to possess various potential medicinal with diverse pharmacological activity spectrum. It is a perennial herb found in all tropics and sub tropics regions. The plant can reach upto a feet height. The plant possess number of medicinal properties, such as antiviral, antimicrobial, anti-inflammatory, immunomodulatory etc.,. Bermuda grass is rich in proteins, carbohydrates, minerals, and other substances like terpenoids, vitamin C, palmitic acid, and alkaloids. The present study focusses on the updates of pharmacognostical and pharmacological properties of the Cynodon dactylon Linn
Effectiveness and safety of cemented and uncemented hemiarthroplasty for the treatment of intracapsular hip fractures:a systematic review and meta-analysis of randomised controlled trials
Aims
We conducted a systematic review and meta-analysis to compare the mortality, morbidity, and functional outcomes of cemented versus uncemented hemiarthroplasty in the treatment of intracapsular hip fractures, analyzing contemporary and non-contemporary implants separately.
Methods
PubMed, Medline, EMBASE, CINAHL, and Cochrane Library were searched to 2 February 2020 for randomized controlled trials (RCTs) comparing the primary outcome, mortality, and secondary outcomes of function, quality of life, reoperation, postoperative complications, perioperative outcomes, pain, and length of hospital stay. Relative risks (RRs) and mean differences (with 95% confidence intervals (CIs)) were used as summary association measures.
Results
A total of 18 studies corresponding to 16 non-overlapping RCTs with a total of 2,819 intracapsular hip fractures were included. Comparing contemporary cemented versus uncemented hemiarthroplasty, RRs (95% CIs) for mortality were 1.32 (0.44 to 3.99) perioperatively, 1.01 (0.48 to 2.10) at 30 days, and 0.90 (0.71 to 1.15) at one year. The use of contemporary cemented hemiarthroplasty reduced the risk of intra- and postoperative periprosthetic fracture. There were no significant differences in the risk of other complications, function, pain, and quality of life. There were no significant differences in perioperative outcomes except for increases in operating time and overall anaesthesia for contemporary cemented hemiarthroplasty with mean differences (95% CIs) of 6.67 (2.65 to 10.68) and 4.90 (2.02 to 7.78) minutes, respectively. The morbidity and mortality outcomes were not significantly different between non-contemporary cemented and uncemented hemiarthroplasty.
Conclusion
There are no differences in the risk of mortality when comparing the use of contemporary cemented with uncemented hemiarthroplasty in the management of intracapsular hip fractures. Contemporary cemented hemiarthroplasty is associated with a substantially lower risk of intraoperative and periprosthetic fractures
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