Effect of Synthesis Time and Treatment on Porosity of Mesoporous Silica Materials

Nitrogen adsorption at 77 K on mesoporous silica materials (MPS) with varying synthesis time and treatment conditions was investigated. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were also used to characterize the mesoporous materials. This study was performed at 6, 24 and 72-h synthesis times. It is shown that 6-h is not enough for complete formation of the MPS material and at least 24-h is necessary. The pore structure starts decaying for the 72-h synthesis time. The three-after-synthesis treatment conditions used were 1) washed, 2) washed and calcined and 3) directly calcined after synthesis. Ethanol/HCl mixtures were used for washing and calcinations were performed at 550°C. Among these samples, directly washed sample yields the lowest adsorption capacity while washed and calcined sample yields the highest adsorption capacity. Hence, it is concluded that washing stabilizes the structure before high temperature treatment

Effect of Synthesis Time and Treatment on Porosity of Mesoporous Silica Materials

Nitrogen adsorption at 77 K on mesoporous silica materials (MPS) with varying synthesis time and treatment conditions was investigated. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were also used to characterize the mesoporous materials. This study was performed at 6, 24 and 72-h synthesis times. It is shown that 6-h is not enough for complete formation of the MPS material and at least 24-h is necessary. The pore structure starts decaying for the 72-h synthesis time. The three-after-synthesis treatment conditions used were 1) washed, 2) washed and calcined and 3) directly calcined after synthesis. Ethanol/HCl mixtures were used for washing and calcinations were performed at 550°C. Among these samples, directly washed sample yields the lowest adsorption capacity while washed and calcined sample yields the highest adsorption capacity. Hence, it is concluded that washing stabilizes the structure before high temperature treatment

Ischemic stroke subtypes and migraine with visual aura in the ARIC study

OBJECTIVE: To investigate the association among migraine, ischemic stroke, and stroke subtypes in the Atherosclerosis Risk in Communities (ARIC) study. METHODS: In this ongoing, prospective, longitudinal community-based cohort study, participants were given an interview ascertaining migraine history in 1993-1995, and were followed for all vascular events, including stroke. All stroke events over the subsequent 20 years were adjudicated and classified into stroke subtypes by standard definitions. Cox proportional hazards models adjusted for stroke risk factors were used to study the relationship between migraine and ischemic stroke, overall, as well as stroke subtypes (cardioembolic, lacunar, or thrombotic). RESULTS: We identified 1,622 migraineurs among 12,758 participants. Mean age of the study population at the 3rd clinical visit was 59 years. When compared to nonheadache participants, there was a significant association between migraine with visual aura and ischemic stroke (hazard ratio [HR] 1.7, 95% confidence interval [CI] 1.2-2.6, p = 0.008). Migraine without visual aura was not significantly associated with ischemic stroke (HR 1.2, CI 1.0-1.8, p = 0.28) when compared to nonheadache participants. Among the 3 subtypes of ischemic stroke evaluated, migraine with visual aura was significantly associated only with cardioembolic stroke (HR 3.7, 95% CI 1.6-8.7, p = 0.003). CONCLUSION: In participants with migraine with visual aura in late middle age, increased risk of cardioembolic stroke was observed. Migraine with visual aura was linked to increased stroke risk, while migraine without visual aura was not, over the period of 20 years. These results are specific to older migraineurs

Ownership illusions in patients with body delusions: : Different neural profiles of visual capture and disownership

© 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CCBY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) funded by European Research Council. The version of record, Martinaud, O., et al., 'Ownership illusions in patients with body delusions: Different neural profiles of visual capture and disownership,' Cortex, Vol 87, Special Issue, pp. 174-185, first published online 19 October 2016, is available online at doi: http://dx.doi.org/10.1016/j.cortex.2016.09/025The various neurocognitive processes contributing to the sense of body ownership have been investigated extensively in healthy participants, but studies in neurological patients can shed unique light into such phenomena. Here, we aimed to investigate whether visual capture by a fake hand (without any synchronous or asynchronous tactile stimulation) affects body ownership in a group of hemiplegic patients with or without disturbed sensation of limb ownership (DSO) following damage to the right hemisphere. We recruited 31 consecutive patients, including seven patients with DSO. The majority of our patients (64.5% overall and up to 86% of the patients with DSO) experienced strong feelings of ownership over a rubber hand within 15 sec following mere visual exposure, which correlated with the degree of proprioceptive deficits across groups and in the DSO group. Using voxel-based lesion-symptom mapping analysis, we were able to identify lesions associated with this pathological visual capture effect in a selective fronto-parietal network, including significant voxels (p < .05) in the frontal operculum and the inferior frontal gyrus. By contrast, lesions associated with DSO involved more posterior lesions, including the right temporoparietal junction and a large area of the supramarginal gyrus, and to a lesser degree the middle frontal gyrus. Thus, this study suggests that our sense of ownership includes dissociable mechanisms of multisensory integration.Peer reviewedFinal Published versio

IN-SITU GROWTH OF POROUS ALUMINO-SILICATES AND FABRICATION OF NANO-POROUS MEMBRANES

Feasibility of depositing continuous films of nano-porous alumino-silicates, primarily zeolites and MCM-41, on metallic and non-metallic substrates was examined with an aim to develop membranes for separation of gaseous mixtures and also for application as hydrogen storage material. Mesoporous silica was deposited in-side the pores of these nano-porous disks with an aim to develop membranes for selective separations. Our study involves supported zeolite film growth on substrates using in-situ hydrothermal synthesis. Faujasite, Silicalite and Mesoporous silica have been grown on various metallic and non-metallic supports. Metallic substrates used for film growth included anodized titanium, sodium hydroxide treated Titanium, Anodized aluminum, and sintered copper. A non-metallic substrate used was nano-porous aluminum oxide. Zeolite film growth was characterized using Scanning Electron Microscope (AMRAY 1820) and High Resolution Transmission electron microscope. Silicalite was found to grow uniformly on all the substrates to form a uniform and closely packed film. Faujasite tends to grow in the form of individual particles which do not inter-grow like silicalite to form a continuous film. Mesoporous silica was found to grow uniformly on anodized aluminum compared to growth on sintered copper and anodized titanium. Mesoporous silica growth on Anodisc® was found to cover more than half the surface of the substrate. Commercially obtained Anodisc® was found to have cylindrical channels of the pore branching into each other and since we needed pore channels of uniform dimension for Mesoporous silica growth, we have fabricated nano-porous alumina with uniform pore channels. Nano-porous alumina membranes containing uniform distribution of through thickness cylindrical pore channels were fabricated using anodization of aluminum disks. Free-standing nano-porous alumina membranes were used as templates for electro-deposition in order to fabricate nickel and palladium nano-wire mesh with large surface area to volu

In-Situ Growth of Zeolites and Mesoporous Silica on Metal Substrates

Hydrogen economy in the forthcoming years demands a need to find viable methods for on-board storage of hydrogen for transportation purposes. Our study is aimed at developing sub-nanostructured metal grids for hydrogen absorption in storage applications. Metal phase will be grown into a zeolite mold which is uniformly grown on the cathode by in- situ hydrothermal synthesis of zeolites. The various parameters involved in modeling in-situ hydrothermal synthesis of zeolite are Al/Si ratio, synthesis reaction chemistry, time-temperature combination for the synthesis and the substrate used for zeolite deposition. Various zeolites synthesized for developing a zeolite layer were faujasite, mesoporous silica and silicalite. Crystal morphology changed with change in concentration of the reaction chemistry. The aspect ratio of silicalite crystals increased by two-fold and the crystal size decreased five fold length and ten fold in width with a four-fold decrease in the reaction chemistry. Time of synthesis also affected change in the zeolite phase, for instance Zeolite-X going to Zeolite-P for longer synthesis times. Choice of the substrate and its surface morphology also affects the growth of the zeolite layer. Micro-scale roughening of the metal surface serves as nucleation sites during zeolite synthesis and thus provides better adhesion between the metal and zeolite film. For this reason, sintered copper surface with particle size in the range 50 microns - 75 microns were employed as the substrate. Hydrothermal faujasite synthesis is performed to control morphology for better adhesion to the cathode. Physical characterization techniques include SEM, AFM, HRTEM and XRD. The technical approach involves, coating a cathode with zeolites to act as template

Inpatient mortality and its predictors after pericardiocentesis: an analysis from the Nationwide Inpatient Sample 2009–2013

Background: National registries have provided data on in-hospital outcomes for several cardiac procedures. The available data on in-hospital outcomes and its predictors after pericardiocentesis are mostly derived from single center studies. Furthermore, the outcomes after pericardiocentesis for iatrogenic pericardial effusion and the impact of procedural volume on in-hospital outcomes in the United States are largely unknown. Methods: We used national inpatient database files for the years 2009–2013 to estimate the inpatient outcomes after pericardiocentesis in all-comers and in the subgroups with iatrogenic effusion. We also studied the impact of hospital procedural volume, among other predictors, on inpatient mortality. Results: About 64,070 (95%CI 61 008-67 051) pericardiocentesis were performed in the United States during 2009-2013. Of these, 57.15% (56.02-58.26%) of the pericardiocentesis were in hemodynamically unstable patients. Percutaneous cardiac procedures were performed in 17.7% of patients (percutaneous coronary intervention (PCI) 4.02%, electrophysiologic procedures 13.58%, and structural heart intervention (SHI) 0.76%). Overall inpatient mortality was 12.30% (95%CI 11.66-12.96%). Inpatient mortality after PCI, electrophysiologic procedures, SHI and cardiac surgery were 27.67% (95%CI 24-31.67%), 7.8% (95%CI 6.67-9.31%), 22.36% (95%CI 15.06-31.85%) and 18.97% (95%CI 15.84-22.57%), respectively. There was an inverse association between hospital procedural volume and inpatient mortality, with a mortality of 14.01% (12.84-15.26%) at the lowest and 10.82% (9.44-12.37%) at highest quartile hospitals by procedure volume (p= 0.001). Conclusion: The inpatient mortality after pericardiocentesis is high, particularly when associated with PCI and SHI

Migraine Age of Onset and Association With Ischemic Stroke in Late Life: 20 Years Follow‐Up in ARIC

Background and Purpose: To evaluate the association between cumulative exposure to migraine and incidence of ischemic stroke in the Atherosclerosis Risk in Communities (ARIC) study. Methods: In this ongoing, prospective longitudinal community-based cohort, participants were interviewed to ascertain migraine history at the third visit (1993–1995), followed for ischemic stroke incidence over 20 years. We performed a post hoc analysis to evaluate the association between the age of migraine onset and ischemic stroke. Results: We identified 447 migraineurs with aura (MA) and 1128 migraineurs without aura (MO) among 11,592 black and white participants. There was an association between the age of MA onset ≥50 years old (average duration = 4.75 years) and ischemic stroke when compared to no headache group (multivariable adjusted HR = 2.17, 95% CI [1.39–3.39], P <.001). MA onset <50 years old (average duration = 28.17 years) was not associated with stroke (multivariable adjusted HR = 1.31, 95% CI [0.86–2.02], P =.212). These results were consistent with our logistic regression model. MO was not associated with increased stroke regardless of the age of onset. The absolute risk for stroke in migraine with aura is 37/447 (8.27%) and migraine without aura is 48/1128 (4.25%). Conclusion: As compared to the no headache participants, increased stroke risk in late life was observed in participants with late onset of MA. In this cohort, longer cumulative exposure to migraine with visual aura, as would be expected with early onset of migraine, was not associated with increased risk of ischemic stroke in late life. This study underscores the importance of the age of onset of MA in assessing stroke risk in older migraineurs