Comparison of antimicrobial sensitivity to older and newer quinolones versus piperacillin-tazobactam, cefepime and meropenem in febrile patients with cancer in two referral pediatric centers in Tehran, Iran

Background: Infection in pediatric cancer patients has become a concerning problem due to increasing antimicrobial resistance. The goal of this study was to determine the antimicrobial resistance patterns of blood isolates from pediatric oncology patients in Iran to determine if there was significant resistance to quinolones. Methods: Children with cancer who were admitted with or developed fever during admission to Aliasghar Children's Hospital or Mahak Hospitals July 2009 through June 2011 were eligible for enrollment. Two blood cultures were obtained. Antimicrobial sensitivity test was performed for ciprofloxacin, moxifloxacin, gatifloxacin, meropenem, cefepime, and piperacillin-tazobactam on isolates from children who were bacteremic. Results: Blood cultures were positive for 38 episodes in 169 enrolled children but 9 episodes were excluded as blood cultures were thought to be contaminated, yielding a bacteremia rate of 29/160 (18). The mean age of children and the stage of malignancy did not differ between those with and without bacteremia. Meropenem was the most likely antibiotic to cover isolates (97) with cefepime having the lowest coverage rate (21). Quinolone coverage ranged from 63 to 76. Conclusion. Quinolones may not be suitable for use as empiric therapy in febrile pediatric oncology patients in Iran

Prediction of second neurological attack in patients with clinically isolated syndrome using support vector machines

The aim of this study is to predict the conversion from clinically isolated syndrome to clinically definite multiple sclerosis using support vector machines. The two groups of converters and non-converters are classified using features that were calculated from baseline data of 73 patients. The data consists of standard magnetic resonance images, binary lesion masks, and clinical and demographic information. 15 features were calculated and all combinations of them were iteratively tested for their predictive capacity using polynomial kernels and radial basis functions with leave-one-out cross-validation. The accuracy of this prediction is up to 86.4% with a sensitivity and specificity in the same range indicating that this is a feasible approach for the prediction of a second clinical attack in patients with clinically isolated syndromes, and that the chosen features are appropriate. The two features gender and location of onset lesions have been used in all feature combinations leading to a high accuracy suggesting that they are highly predictive. However, it is necessary to add supporting features to maximise the accuracy. © 2013 IEEE

Commuting probability of compact groups

http://dx.doi.org/10.1017/S000497271200033

Dynamic study of a field emission sensor based on carbon nanotubes for acceleration and high frequency vibration sensing

Plasma enhanced chemical vapor deposition was used to grow vertically aligned carbon nanotubes (CNTs) on silicon substrate. Field emission from these nanotubes was realized and used to fabricate a field emission-based sensor. Titanium dioxide was used as spacing layer between the emitters and a flexible anode made of silicon membrane. The variation of the emission current during mechanical vibration of the silicon membrane was measured and compared with a theoretical prediction. Experimental results show that field emission from CNTs is a good candidate for high frequency vibration sensing, measurement of resonance frequency, fabrication of accelerometer and other types of mechanical sensors. The fabricated device, due to a low distance between its electron emitters and the anode, works at low voltages with high emission current

Microstructural evolution and tensile properties of the in situ Al-15%Mg<inf>2</inf>Si composite with extra Si contents

In the present work, the effect of extra Si addition on the microstructure and tensile properties of Al-15%Mg2Si composite has been investigated. The Al-15%Mg2Si composite ingot was made by in situ process and different amounts of extra Si (0.5, 1, 1.5, 2, 5 and 7wt.% Si) were added to the remelted composite. Optical microscopy and scanning electron microscopy (SEM) indicated that the addition of extra Si up to 2wt.%, reduces the average Mg2Si particle size from 39μm to 26μm and increases the volume fraction of α-Al phase from 6% to 22%. Addition of extra Si content up to 7wt.% leads to the formation of primary Mg2Si particles with larger size (38μm). The results of tensile test revealed that the addition of extra Si improves ultimate tensile strength (UTS) and elongation values of the composite from 176MPa and 1.7% to 222MPa and 3.0% respectively. Fractographic analysis of specimens exposed a cellular nature for the fracture surface. On the cellular fracture surface, the features of both brittle and ductile fracture were present simultaneously. Raising the amount of extra Si up to 7% has increased the number and decreased the size of dimples. These microstructural findings led to a change in the mode of fracture from brittle to ductile and increased elongation values. © 2011 Elsevier Ltd

Successful Coronary Artery Bypass Operation in a SARS-COV-2 Infected Patient with Acute Coronary Syndrome

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is overwhelming healthcare resources and infrastructure worldwide. Earlier reports have demonstrated complicated postoperative courses and high fatality rates in patients undergoing emergent cardiothoracic surgery who were diagnosed postoperatively with COVID-19. These reports raise the possibility that active COVID-19 might precipitate a catastrophic pathophysiological response to infection in the postoperative period and lead to unfavorable surgical outcomes. Hence, it is imperative to screen patients with SARS-CoV-2 infection before surgery and to carefully monitor them in the postoperative period to identify any signs of active COVID-19. In this report, we present the successful outcome of coronary artery bypass grafting (CABG) operation in a patient with asymptomatic SARS-CoV-2 infection presenting with an acute coronary syndrome and requiring urgent surgical intervention. We employed a thorough strategy to identify subclinical COVID-19 disease, and after confirming the absence of active disease, proceeded with the CABG operation. The patient outcome was successful with the absence of any overt COVID-19 manifestations in the postoperative period

Microstructure and tensile properties of cast Al-15%Mg <inf>2</inf>Si composite: Effects of phosphorous addition and heat treatment

The effects of solution heat treatment and phosphorous addition on the microstructure and tensile properties of in situ Al-15%Mg 2Si composite specimens have been investigated. The Al-15%Mg 2Si composite ingot was made by in-situ process and different amounts of phosphorous (0.1, 0.3, 0.5, 0.7 and 1wt% P) were added to the remelted composite. Then, the specimens were subjected to solutionizing at 500°C for holding time of 4h followed by quenching. Optical microscopy (OM) and scanning electron microscopy (SEM) indicated that phosphorous addition not only changes the morphology of primary Mg 2Si particles from dendritic to a regular shape, but also it reduces Mg 2Si particle size. Solutionizing led to the dissolution of the Mg 2Si particles and changed their morphology to round shape. The results obtained from tensile testing revealed that both phosphorous addition and solution heat treatment improve ultimate tensile strength (UTS) and elongation (El.%) values. According to the results, the optimum tensile property was achieved by adding 0.5wt% P to the Al-Mg 2Si composite after solution heat treatment. Fractographic analysis revealed a cellular nature for the fracture surface of the MMC. As a result of P addition the potential sites for stress concentration and crack initiation areas were reduced due to microstructural modification, while increase in the number of fine dimples rendered the nature of fracture from brittle to ductile and also improved tensile properties. © 2012 Elsevier B.V

The usage of computer-aided cooling curve thermal analysis to optimise eutectic refiner and modifier in Al-Si alloys

Bismuth, antimony and strontium concentrations were optimised to alter the eutectic Al-Si phase in a commercial Al-Si-Cu-Mg alloy by way of computer-aided cooling curve thermal analysis. The results show that the eutectic growth temperature shifted to lower temperatures for all three inoculants. However, addition of Sr resulted in more depression of growth temperature compared with Bi and Sb. No further significant changes were observed with increasing the concentrations to more than 1, 0.5 and 0.04 wt% of Bi, Sb and Sr, respectively. The recalescence of these concentrations, meanwhile, showed a significant increase of magnitude. A good correlation was found between the results of thermal and microstructural analysis. For Bi and Sb, the eutectic depression temperature can be used as an individual criterion to gauge optimal levels of content in the refinement of Si, whereas for Sr, both depression temperature and recalescence magnitude must be considered. Based on the observed depression in eutectic growth temperature and recalescence, it can be concluded that the optimal concentrations to refine the eutectic Al-Si phase with Bi and Sb and to modify it with Sr at the given solidification conditions were 1, 0.5 and 0.04 wt%, respectively