Highly selective palladium supported catalyst for hydrogenation of phenol in aqueous phase

Hydrogenation of phenol to cyclohexanone in aqueous phase, under mild conditions, has been carried out using palladium on different supports such as hydroxyapatite (HA), carbon (C), alumina (γ-Al₂O₃) and Al₂O₃-CWE synthesized with high surface area. High activity (100%) and selectivity (98%) to cyclohexanone was obtained using Pd/ Al₂O₃-CWE catalyst in 50 min under mild reaction conditions.     

Selection of the more adequate prediction index to estimate the frame size a group of institutionalized and free living elderly in Venezuela. (Preliminary study)

The objective of the study was to identify an easy to measure indicator of body frame size to allow refinement of anthropometric nutritional evaluation. Body dimensions and frame indices related to height, which might be potential frame size predictors in the elderly, were studied. In 307 subjects (163 women, 144 men) aged 60-99 years of whom 187 were institutionalized and 120 free-living outpatients, weight, height, mid-arm circumference; triceps, subscapular, midthigh and calf skinfolds; elbow, wrist, femur and biacromial widths, were measured. Body mass index, upper arm muscle area, upper arm fat area, fat percentage, sum of skinfolds and frame indices were calculated. Results were calculated in function of age, sex and life-style. Biacromial breadth, biacromial/height index, wrist breadth and wrist/height index gave variable correlations with indices of body mass and body fat. Femur breadth and femur/height index were significantly correlated with body fat indices. Elbow breadth, humerus/height index were not correlated to body fat indices, but were significantly correlated with weight, height and fat free mass. Elbow breadth and humerus/height index fulfilled most of the criteria of good predictors of body frame size in the group pf elderly studied.     

Dual action of neutral sphingomyelinase on rat hepatocytes: Activation of cholesteryl ester metabolism and biliary cholesterol secretion and inhibition of VLDL secretion

To address the role of cell membrane neutral sphingomyelinase (EC 3.1.4.12; SMase) in the regulation of cholesterol metabolism in the liver parenchymal cell, we examined the effect of exogenous neutral SMase on the metabolism of cholesteryl esters and the secretion of VLDL and biliary lipids in isolated rat hepatocytes. We show that treatment of hepatocytes with SMase (20 mU/mL) resulted in the intracellular buildup of cholesteryl esters, increased ACAT (EC 2.3.1.26) activity without affecting the ACAT2 mRNA level, and increased cytosolic and microsomal cholesteryl ester hydrolase (EC 3.1.1.13) activity. This was accompanied by increases in the secretion of biliary. bile acid, phospholipid, and cholesterol and in increased cholesterol 7α-hydroxylase (EC 1.14.13.17) activity and levels of mRNA, as well as decreased levels of apoB mRNA and a decreased secretion of VLDL apoB (apoB-48, ∼45%; apoB-100, ∼32%) and lipids (∼55%). Moreover, the VLDL particles secreted had an abnormal size and lipid composition; they were larger than controls, were relatively enriched in cholesteryl ester, and depleted in TG and cholesterol. Cell-permeable ceramides did not replicate any of the reported effects. These findings demonstrate that the increased cholesteryl ester turnover, oversecretion of biliary cholesterol and bile acids, and undersecretion of VLDL cholesterol and particles are concerted responses of the primary hepatocytes to exogenous neutral SMase brought about by regulation at several levels. We suggest that plasma membrane neutral SMase may have a specific, ceramide-independent effect in the regulation of cholesterol out-put pathways in hepatocytes.     

Tailoring reversible insulin aggregates loaded in electrosprayed arabinoxylan microspheres intended for colon-targeted delivery

Arabinoxylans (AX) covalent gels are little affected by pH changes and fermentable by colonic microbiota, which make them suitable for insulin oral administration and colon-targeted delivery. In this work, the tailoring of insulin aggregates size using glutamic acid and their loading in AX microspheres (2%w/v) prepared by triaxial electrospray is presented. Dynamic light scattering showed that insulin-glutamic acid aggregates are reversible under intestinal conditions. AX microspheres presented a spherical shape, a mean diameter of 233 μm, a heterogeneous microstructure as shown by scanning electron microscopy, and a homogeneous distribution of insulin aggregates as observed by confocal laser scanning microscopy. In this AX-insulin system, 20% of insulin is released under simulated gastrointestinal pH conditions, indicating that most of the insulin stays into the microspheres, available for colonic release. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47960.     

'Heading up the street:' localised opportunities for shared constructions of knowledge

Success and failure in school is contingent upon one's ability to regulate and situate identities, utilise culturally-developed semiotic tools and negotiate models of meaning in shared social activity.However, many language minority students lack such success, struggling with conflicts between their primary-and community-based identities, and existing personal models of the world instantiated through community-based Discourses on the one hand, and discrepant new constructs and literate Discourses, on the other.We compare and contrast linguistic and non-linguistic components of ways of speaking, being, performing and reasoning, within an urban African-American secondary classroom and an African-American mid-western hair salon.We identify culturally-shared interactional norms that inform knowledge building across both sites.We analyse how the Discourse norms and structures of argumentation evident in the hair salon provide participation structures that invite engagement with complex problem solving tasks in both sites.The semiotic potential of these participation structures is heightened in the classroom context by providing scaffolding tasks where students draw on tacit conceptual knowledge constructed from their home/community experiences and that is analogous to the target academic task.     

Network delay tomography

The substantial overhead of performing internal network monitoring motivates techniques for inferring spatially localized information about performance using only end-to-end measurements. In this paper, we present a novel methodology for inferring the queuing delay distributions across internal links in the network based solely on unicast, end-to-end measurements. The major contributions are: 1) we formulate a measurement procedure for estimation and localization of delay distribution based on end-to-end packet pairs; 2) we develop a simple way to compute maximum likelihood estimates (MLEs) using the expectation-maximization (EM) algorithm; 3) we develop a new estimation methodology based on recently proposed nonparametric, wavelet-based density estimation method; and 4) we optimize the computational complexity of the EM algorithm by developing a new fast Fourier transform implementation. Realistic network simulations are carried out using network-level simulator ns-2 to demonstrate the accuracy of the estimation procedure.     

Progress Toward the Rehabilitation of Lake Trout (Salvelinus namaycush) in South Bay,Lake Huron

Our objective was to evaluate the status of lake trout Salvelinus namaycush rehabilitation in South Bay, Lake Huron. Standardized surveys were conducted to quantify natural recruitment, annual mortality, and the contribution of wild-versus hatchery-origin lake trout. Some indicators suggest a high level of natural recruitment. The spawning population was comprised of multiple ages, and the mean age of spawners (8.4 years for females, 7.9 years for males) was at least 1 year older than the age at 50% maturity (5.8 years). Estimated annual total mortality rates (0.20–0.25) and sea-lamprey induced mortality rates (0.02) were less than maximum allowable values. The proportion of wild-origin fish captured was high among spawners but varied among sampling programs (42% in fall trap nets, 70% in fall gill nets, and 88% in summer gill nets). A strong year class (1997) could be tracked from 2001 to 2005. Few fish were captured from early (< 1996) or later (1999–2002) year classes. Possible explanations for low natural recruitment during these later years include declining spawning habitat quality caused by low water levels and/or invasion of non-native mussels (Dreissena spp.) and/or direct or indirect effects of alewife (Alosa pseudoharengus).     

Accelerating Scientific Discovery Through Computation and Visualization II

This is the second in a series of articles describing a wide variety of projects at NIST that synergistically combine physical science and information science. It describes, through examples, how the Scientific Applications and Visualization Group (SAVG) at NIST has utilized high performance parallel computing, visualization, and machine learning to accelerate research. The examples include scientific collaborations in the following areas: (1) High Precision Energies for few electron atomic systems, (2) Flows of suspensions, (3) X-ray absorption, (4) Molecular dynamics of fluids, (5) Nanostructures, (6) Dendritic growth in alloys, (7) Screen saver science, (8) genetic programming.     

Keep Your Data Safe and Available While Roaming

The possibility of accessing and/or receiving local or remote data anywhere and at anytime constitutes an important advantage in many business environments. However, when working with mobile devices, users face many problems, such as: (1) devise exposure problems – mobile devices are more vulnerable and fragile than stationary devices, because they can be easily stolen, lost or damaged, (2) media problems – wireless communications are often unstable, asymmetric and expensive, and (3) availability problems – mobile devices stay disconnected for long periods of time. To alleviate these problems, we present a service, Data Lockers, which offers to its users first, the possibility of keeping their data in a secure and safe space in a proxy, thus alleviating the device exposure problem. Next, data stored in a data locker are available even when the mobile device is disconnected, thus providing a solution to the availability problem. Finally, specific tasks are carried out at the fixed network on behalf of the mobile user, in this way relieving the media problem. The architecture of the Locker Rental Service is based on mobile agents. These agents, and the locker, stay always close to the location of the user, traveling to meet the user wherever the user moves, therefore, allowing users to use anywhere-anytime, ubiquitous persistent storage space located at the fixed network.