Solvent-free oxidation of benzyl alcohol with oxygen using zeolite-supported Au and Au–Pd catalysts

The oxidation of benzyl alcohol to benzaldehyde has been investigated in the absence of solvent using zeolite-supported Au and Au–Pd catalysts. Three zeolites were investigated, ZSM-5, zeolite β and zeolite Y, and these were contrasted with the titanoslicalite TS-1 and TiO₂ as supports. For the Au catalysts the best results are obtained with zeolite β as the support and the conversions were comparable or better than those observed with TiO₂ in terms of turn over frequencies. However, the selectivities observed with the acidic zeolites were lower than the non-acidic TS-1 and TiO₂. This is due to the subsequent reaction of benzaldehyde via acid catalysed reactions to give benzyl benzoate and its dibenzyl acetal, and, in some cases dibenzylether. Initial catalysts were evaluated with a gold loading of 2 wt% and increasing this to 4 wt% showed the expected increase in activity, indicating that there is scope to improve the performance of these catalysts. The most active catalysts were prepared by impregnation and catalysts prepared by deposition precipitation were considerably less active. Introduction of Pd into the catalyst improved the activity without significantly affecting the selectivity.     

Time and shear dependent rheology of maleated polyethylene and its nanocomposites

Dipole-dipole and/or hydrogen-bonding interactions between the pendant functional groups within maleated high-density polyethylene (PE-g-MAn) establish a physical polymer network, whose formation kinetics and shear-sensitivity are revealed by dynamic oscillatory testing. The pronounced time and shear dependent viscoelastic properties of PE-g-MAn were not observed for a corresponding imide derivative, PE-g-imide, presumably due to weakened functional group associations in the latter material.The melt compounding of PE-g-MAn with onium-ion exchanged montmorillonite clay (NR₄⁺-MM) resulted in a partially exfoliated hybrid nanocomposite structure, whose viscoelastic behaviour differed significantly from that of the unfilled polymer. The presence of dispersed clay platelets altered the extent of functional group associations, thereby changing the dynamics of network formation.     

Brain mass estimation by head circumference and body mass methods in neonatal glycaemic modelling and control

Introduction

Hyperglycaemia is a common complication of stress and prematurity in extremely low-birth-weight infants. Model-based insulin therapy protocols have the ability to safely improve glycaemic control for this group. Estimating non-insulin-mediated brain glucose uptake by the central nervous system in these models is typically done using population-based body weight models, which may not be ideal.

Method

A head circumference-based model that separately treats small-for-gestational-age (SGA) and appropriate-for-gestational-age (AGA) infants is compared to a body weight model in a retrospective analysis of 48 patients with a median birth weight of 750 g and median gestational age of 25 weeks. Estimated brain mass, model-based insulin sensitivity (S_I) profiles, and projected glycaemic control outcomes are investigated. SGA infants (5) are also analyzed as a separate cohort.

Results

Across the entire cohort, estimated brain mass deviated by a median 10% between models, with a per-patient median difference in S_I of 3.5%. For the SGA group, brain mass deviation was 42%, and per-patient S_I deviation 13.7%. In virtual trials, 87–93% of recommended insulin rates were equal or slightly reduced (Δ < 0.16 mU/h) under the head circumference method, while glycaemic control outcomes showed little change.

Conclusion

The results suggest that body weight methods are not as accurate as head circumference methods. Head circumference-based estimates may offer improved modelling accuracy and a small reduction in insulin administration, particularly for SGA infants.     

Role of semiochemicals in mate location by parasitic sea louse,Lepeophtheirus salmonis

The role of olfaction and diffusible pheromones in mate location behavior of sea lice, Lepeophtheirus salmonis, was assessed with Y-tube behavioral bioassays. The pheromone emitting animals were located in a chamber in one arm of a Y-tube arena, with artificial seawater flowing through both arms. Adult male sea lice displayed both activation and directional responses to seawater conditioned with preadult II virgin females, but were only activated by mated adult female conditioned water. Further, when males were given the choice of preadult II virgin females or mated adult females, a significant number of males chose the arm with the preadult II virgin females. Adult males showed activation responses when presented with water conditioned with adult males but were not attracted to them. When presented with adult males, preadult II virgin females showed only directional responses, but not activation responses. Preadult II virgin female conditioned water was extracted using solid-phase extraction (SPE) protocols pioneered for semiochemical isolation. Adult male sea lice showed significant directional responses to the preadult II virgin female SPE extract. Distillation under vacuum was performed on the extract to give a distillate comprising components with a molecular weight range and physical properties comparable to those of compounds utilized as volatile semiochemicals by terrestrial organisms and a residue comprising components with higher molecular weight range comparable to those utilized as involatile semiochemicals. Adult males were found to be both significantly activated and attracted to the distillate, but not to the residue. This research provides evidence that small, lipophilic organic molecules are used by sea lice as sex pheromone signals to locate a member of the opposite sex.     

Scales to measure parents and caretakers satisfaction with the food and nutrition component of Child care Centers

Two Likert-type scales for measuring parents' and caretakers' level of satisfaction with the food and nutrition services offered at childcare multi-centers in a peri-urban community in Caracas, were developed and validated. An intentional sample of 20 parents and caretakers were interviewed within the naturalistic-constructivist perspective, to capture their perceptions of distinct aspects of the food and nutrition components of the program. Categories emerged from the interviews that served to construct the items for two scales that measure level of satisfaction of parents and caretakers with the food and nutrition aspects of the program. To validate the scales, they were applied to 73 parents and 32 caretakers. Factor and multiple components analysis showed that overall, the scales explained 61% and 69% of the variation in level of satisfaction of parents and caretakers respectively. Confiability measured with Alpha Cronbach coefficient was 0.74 and 0.77 for parents' and caretakers' scales respectively. These results reveal scales that have content validity and good reliability. Besides, the scales detect specific aspects of the food and nutrition service that should be reinforced or modified, to make the Child-care Centers program more effective and efficient. External validation of the scales is recommended, since they provide an instrument capable of capturing useful information for monitoring and evaluating the Child-care Centers program nation-wide, from the perspective of program managers and parents of program users.     

Public Displays of Play: Studying Online Games in Physical Settings

As research on virtual worlds gains increasing attention in educational, commercial, and military domains, a consideration of how player populations are ‘reassembled’ through social scientific data is a timely matter for communication scholars. This paper describes a large‐scale study of virtual worlds in which participants were recruited at public gaming events, as opposed to through online means, and explores the dynamic relationships between players and contexts of play that this approach makes visible. Challenging conventional approaches to quantitatively driven virtual worlds research, which categorizes players based on their involvement in an online game at a particular point in time, this account demonstrates how players' networked gaming activities are contingent on who they are playing with, where, and when.     

Fear Appeals,Message Processing Cues,and Credibility in the Websites of Violent,Ideological, and Nonideological Groups

Ideological groups use the Internet to deliver their messages unhindered by the constraints of traditional media. We examined how ideological groups promote their worldview through their websites. Using the elaboration likelihood model (ELM), this research used trained coders to examine the websites of nonideological groups (n = 37), nonviolent ideological groups (n = 36), and violent ideological groups (n = 32) for credibility, persuasion processing cues, and interactivity factors. Results of this study found that the websites of violent ideological groups use more fear appeals, were less interactive, and were the least credible of the 3 groups. All 3 groups used more central cues than peripheral suggesting they focused on evidence for their arguments rather than emotion.     

Health benefits of CLA – lessons from pig models in biomedical research

The objective of this review is to highlight the use of pig models for investigating safety, efficacy and the mechanisms of action of conjugated linoleic acid (CLA). Although CLA elicits positive effects in animal models and in vitro systems, a consistent concern in terms of translational research is that the health benefits observed by using these model systems cannot be extrapolated directly into humans. Conversely, the similarities between pigs and humans make the pig an ideal model for examining the health benefits of dietary supplements, functional foods and nutraceuticals. We have developed pig models of viral and bacterial infection to examine the preventive role of dietary CLA supplementation on virally induced immunosuppression and gut health, respectively. Results from these studies indicate that CLA significantly enhances the immune function while limiting the catabolic effects of uncontrolled immune and inflammatory responses. The scientific findings in pig models and human clinical trials demonstrate that CLA modulates immune responses in pigs and humans. Pig models of immunomodulation represent significant improvements over other animal models and in vitro systems because they mimic more closely the compartmentalization of the human immune system and the clinical presentation of human infectious, immune and inflammatory diseases.     

Solvent-free oxidation of benzyl alcohol using titania-supported gold–palladium catalysts: Effect of Au–Pd ratio on catalytic performance

The oxidation of benzyl alcohol with molecular oxygen under solvent-free conditions has been investigated using a range of titania-supported Au–Pd alloy catalysts to examine the effect of the Au–Pd ratio on the conversion and selectivity. The catalysts have been compared at high reaction temperature (160 °C) as well as at 100 °C, to determine the effect on selectivity since at lower reaction temperature the range of by-products that are formed are limited. Under these conditions the 2.5 wt.% Au–2.5 wt.% Pd/TiO₂ was found to be the most active catalyst, whereas the Au/TiO₂ catalyst demonstrated the highest selectivity to benzaldehyde. Toluene, formed via either a hydrogen transfer process or an oxygen transfer process, was observed as a major by-product under these forcing conditions.     

Obesity: Prevalence,Theories, Medical Consequences,Management, and Research Directions

Obesity and its associated disorders are a growing epidemic across the world. Many genetic, physiological, and behavioral factors play a role in the etiology of obesity. Diet and exercise are known to play a valuable role in the treatment and prevention of obesity and associated disorders such as hypertension, heart disease, and diabetes. Therefore, the purpose of this review is to examine the prevalence, etiology, consequences, and treatment of obesity.