95 research outputs found
Using modular decomposition technique to solve the maximum clique problem
In this article we use the modular decomposition technique for exact solving
the weighted maximum clique problem. Our algorithm takes the modular
decomposition tree from the paper of Tedder et. al. and finds solution
recursively. Also, we propose algorithms to construct graphs with modules. We
show some interesting results, comparing our solution with Ostergard's
algorithm on DIMACS benchmarks and on generated graph
The role of dipole interactions in hyperthermia heating colloidal clusters of densely-packed superparamagnetic nanoparticles
This work aims to investigate the influence of inter-particle dipole interactions on hyperthermia heating colloidal clusters of densely-packed Fe3O4 nanoparticles at low field intensity. Emulsion droplet solvent evaporation method was used to assemble oleic acid modified Fe3O4 particles into compact clusters which were stabilized by surfactant in water. Both experimental and simulation works were conducted to study their heating performance at different cluster’s sizes. The dipole interactions improve the heating only when the clusters are small enough to bring an enhancement in clusters’ shape anisotropy. The shape anisotropy is reduced at greater clusters’ sizes, since the shapes of the clusters become more and more spherical. Consequently, the dipole interactions change to impair the heating efficiency at larger sizes. When the clusters are totally isotropic in shape, the heating efficiency is lower than that of non-interacting particles despite the cluster’s size, although the efficiency increases by a little bit at a particular size most likely due to the dipole couplings. In these situations, one has to use particles with higher magnetic anisotropy and/or saturation magnetization to improve the heating
Serum 25-Hydroxyvitamin D and the Incidence of Acute Viral Respiratory Tract Infections in Healthy Adults
Declining serum concentrations of 25-hydroxyvitamin D seen in the fall and winter as distance increases from the equator may be a factor in the seasonal increased prevalence of influenza and other viral infections. This study was done to determine if serum 25-hydroxyvitamin D concentrations correlated with the incidence of acute viral respiratory tract infections.In this prospective cohort study serial monthly concentrations of 25-hydroxyvitamin D were measured over the fall and winter 2009-2010 in 198 healthy adults, blinded to the nature of the substance being measured. The participants were evaluated for the development of any acute respiratory tract infections by investigators blinded to the 25-hydroxyvitamin D concentrations. The incidence of infection in participants with different concentrations of vitamin D was determined. One hundred ninety-five (98.5%) of the enrolled participants completed the study. Light skin pigmentation, lean body mass, and supplementation with vitamin D were found to correlate with higher concentrations of 25-hydroxyvitamin D. Concentrations of 38 ng/ml or more were associated with a significant (p<0.0001) two-fold reduction in the risk of developing acute respiratory tract infections and with a marked reduction in the percentages of days ill.Maintenance of a 25-hydroxyvitamin D serum concentration of 38 ng/ml or higher should significantly reduce the incidence of acute viral respiratory tract infections and the burden of illness caused thereby, at least during the fall and winter in temperate zones. The findings of the present study provide direction for and call for future interventional studies examining the efficacy of vitamin D supplementation in reducing the incidence and severity of specific viral infections, including influenza, in the general population and in subpopulations with lower 25-hydroxyvitamin D concentrations, such as pregnant women, dark skinned individuals, and the obese
Experience with tacrolimus in children with steroid-resistant nephrotic syndrome
Children with steroid-resistant nephrotic syndrome (SRNS) are at risk of developing renal failure. We report here the results of a single-center retrospective observational study of the remission rate in pediatric patients with SNRS receiving tacrolimus. Serial renal biopsies from children on tacrolimus therapy were evaluated for tubulointerstitial fibrosis and transforming growth factor-β immunostaining. Of the 16 children with SRNS, 15 went into complete remission after a median of 120 days of therapy. Nine children were able to stop steroids, while the others were on tapering doses. Forty-seven percent had relapses, most of which were steroid-responsive. Serial renal biopsies were obtained from seven children after a median treatment duration of 24 months; two of these children had increased tubulointerstitial fibrosis and four showed increased transforming growth factor-β tissue staining. Children with worsening histological findings were younger. There was no significant association between tacrolimus exposure and biopsy changes, although the average trough level was higher in those children with worsening histological findings. In conclusion, tacrolimus may be a safe and effective alternative agent for inducing remission in children with SRNS. However, caution needs to be taken when prescribing this agent due to its narrow therapeutic index. Serial renal biopsies are necessary to check for subclinical nephrotoxicity, especially in younger children and those with higher trough levels
Snake Envenoming: A Disease of Poverty
Every year snake envenoming kills more people in the tropics than some of the world's recognised neglected tropical diseases (NTDs), including schistosomiasis and leishmaniasis. While lacking the epidemic potential of an infectious/vector-borne disease, snake envenoming in rural tropical communities has as great a medical mortality, if not morbidity, as the NTDs. The recent categorisation of snake envenoming as an NTD is an important advance that hopefully will result in the wider recognition and allocation of resources, particularly since death from snake envenoming is preventable; antivenom is very effective when the appropriate antivenom is correctly administered. Snake envenoming urgently requires international support to instigate the epidemiological, health education, and effective treatment initiatives that proved so potent in addressing the medical burden of NTDs such as leprosy and dracunculosis. All the global estimates of snake envenoming and deaths from snakebite indicate that mortality is highest in the world's tropical countries. Here we examined associations between the globally available data on (i) snakebite-induced mortality and (ii) socioeconomic markers of poverty. Our data unequivocally establishes that snake envenoming is globally associated with poverty, a distinctive characteristic of the neglected tropical diseases
A case report and brief review of the literature on bilateral retinal infarction following cardiopulmonary bypass for coronary artery bypass grafting
Postoperative visual loss is a devastating perioperative complication. The commonest aetiologies are anterior ischaemic optic neuropathy (AION), posterior ischaemic optic neuropathy (PION), and central retinal artery occlusion (CRAO). These appear to be related to certain types of operation, most commonly spinal and cardiac bypass procedures; with the rest divided between: major trauma causing excessive blood loss; head/neck and nasal or sinus surgery; major vascular procedures (aortic aneurysm repair, aorto-bifemoral bypass); general surgery; urology; gynaecology; liposuction; liver transplantation and duration of surgery. The non-surgical risk factors are multifactorial: advanced age, prolonged postoperative anaemia, positioning (supine v prone), alteration of venous drainage of the retina, hypertension, smoking, atherosclerosis, hyperlipidaemia, diabetes, hypercoagulability, hypotension, blood loss and large volume resuscitation. Other important cardiac causes are septic emboli from bacterial endocarditis and emboli caused by atrial myxomata. The majority of AION cases occur during CPB followed by head/neck surgery and prone spine surgery. CPB is used to allow coronary artery bypass grafting on a motionless heart. It has many side-effects and complications associated with its use and we report here a case of bilateral retinal infarction during routine coronary artery bypass grafting in a young male patient with multiple risk factors for developing this complication despite steps to minimise its occurrence
Stroke genetics informs drug discovery and risk prediction across ancestries
Previous genome-wide association studies (GWASs) of stroke - the second leading cause of death worldwide - were conducted predominantly in populations of European ancestry(1,2). Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis(3), and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach(4), we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry(5). Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries.</p
Prise en charge des voies aériennes – 1re partie – Recommandations lorsque des difficultés sont constatées chez le patient inconscient/anesthésié
Infective endocarditis in the Netherlands: current epidemiological profile and mortality
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