Effect of vegetarian diets on zinc status: a systematic review and meta‐analysis of studies in humans

Plant‐based diets contain less saturated fat and cholesterol and more folate, fibre and phytochemicals than omnivorous diets, but some micronutrients, especially zinc, are poorly bioavailable. The findings of studies exploring the zinc intake and zinc status in populations that habitually consume vegetarian diets are inconsistent. This study aims to investigate the effects of plant‐based diets on dietary zinc intake and status in humans using systematic review and meta‐analysis techniques. Thirty‐four studies were included in the systematic review. Of these, 26 studies (reporting 48 comparisons) compared males and/or females consuming vegetarian diets with non‐vegetarian groups and were included in meta‐analyses. Dietary zinc intakes and serum zinc concentrations were significantly lower (?0.88 ± 0.15 mg day^?1, P < 0.001 and ?0.93 ± 0.27 µmol L^?1, P = 0.001 respectively; mean ± standard error) in populations that followed habitual vegetarian diets compared with non‐vegetarians. Secondary analyses showed greater impact of vegetarian diets on the zinc intake and status of females, vegetarians from developing countries and vegans. Populations that habitually consume vegetarian diets have low zinc intakes and status. Not all vegetarian categories impact zinc status to the same extent, but a lack of consistency in defining vegetarian diets for research purposes makes dietary assessment difficult. Dietary practices that increase zinc bioavailability, the consumption of foods fortified with zinc or low‐dose supplementation are strategies that should be considered for improving the zinc status of vegetarians with low zinc intakes or serum zinc concentrations at the lower end of the reference range. © 2013 Society of Chemical Industry     

Antimicrobial Activity of Peptide P34 During Thermal Processing

In the present work, the influence of pH and sodium chloride concentration on thermal stability of antimicrobial peptide P34 was evaluated under different time–temperature conditions by a 2² factorial design experiment. At sterilization conditions (121 °C for 20 min), maximum retention (36%) was obtained at pH between 5.5 and 8.5 and sodium chloride concentration between 0.4 and 0.75 mol/l. For boiling conditions (100 °C for 20 min), antimicrobial activity was about 100% combining pH between 6.0 and 8.0 and salt concentration in the range of 0.65 to 1 mol/l. At low temperature pasteurization conditions (30 min at 65 °C), antimicrobial activity was not affected within the pH range from 5.0 to 8.0. For the three time–temperature conditions tested, the antimicrobial activity was minimal at more acidic or alkaline pH. Sodium chloride concentration of 0.65 mol/l increased thermostability of the peptide P34. Combination of sodium chloride and slight alkaline pH may increase the stability of peptide P34, which is essential to the proper utilization of bacteriocins in food industry.     

The evaporation rates and mechanisms of cadmium from a bubble-stirred molten copper bath

Experiments to determine the evaporation rates and aerosol formation mechanism of cadmium in molten copper at atmospheric pressure have been carried out. A small amount of cadmium (∼1 wt pct) was added to molten copper at 1473 K and allowed to evaporate while bubbling 750 and 1500 cm³/min of argon through the melt. Melt samples were periodically taken and analyzed by inductively coupled plasma/mass spectroscopy (ICP/MS) to determine their impurity content. A theoretical model to predict the evaporation rates of solutes from molten metals was developed and compared to the experimental results. Excellent correlation between experiment and theory was found for the cadmiumcopper system. The model has been extended to other solutes and also to molten Fe-3 (wt pct) C at 1873 K as a solvent.     

A Framework for Using Web Services to Enhance QoS for Content Delivery

An integrated approach to quality of service for content delivery using Web services includes quality definitions, user contracts, and fault monitoring.     

An analysis of conformance issues in implementations of standardized security protocols

In the last years the amount of information being transmitted through communication networks has increased, and this has lead to an increased use of security protocols. The implementations of security protocols do not accurately follow the standards and this causes many malfunctions and security flaws. In this paper we will analyze the different approaches followed by the scientific community to evaluate security protocols' implementations, and will also analyze the special characteristics of security protocols, in order to deduce which are the key points for such an evaluation, how they can be evaluated and also if existing evaluation techniques can be used.     

Application of monosaccharides derivatives in colloidal processing of aluminum oxide

Obtaining highly loaded, time-stable and relatively low viscosity suspensions approaches colloidal processing to be very convenient and effective route of shaping of nanopowders. In order to obtain well dispersed, homogenous ceramic slurries, certain additives are given. Saccharides, particularly monosaccharides, as well as their derivatives, were found to be a group of effectively working processing agents in case of alumina, which has been used as a solid phase of highly loaded nanosuspensions. This class of chemical compounds can be described by a series of advantages – they are non-toxic, water-soluble, inexpensive, etc. In this paper suspensions of nano- and submicro-alumina powders with addition of d-fructose, 1-O-methyl-d-fructose, d-glucose and 3-O-acrylic-d-glucose have been studied in terms of their rheological properties, moreover the properties of as-received green bodies have been presented.     

Lanthanum cobaltite nanoparticles using the polymeric precursor method

The present study reports the evolution of reactive lanthanum cobaltite nanoparticles obtained by a polymeric precursor route, using citric acid as chelating agent. The crystallization from amorphous precursor, particle growth and the formation of nanoparticle agglomerates at different calcination temperatures was carried out by conventional and high-resolution electron microscopy, electron diffraction and energy-dispersive X-ray analysis and Raman spectroscopy. Microstructure measurements were compared with X-ray diffraction and chemical analysis results. Electron diffraction, combined with TEM, was used to determine the proportion of amorphous phase. The presence of amorphous carbon during the decomposition of the amorphous precursor was analyzed by Raman spectroscopy. The coherent crystalline domain size and the particle size have been monitored by XRD and electron microscopy in order to determine the evolution of both crystal size and the temperature onset for the formation of polycrystalline aggregates.The results demonstrate that at 550 °C we obtain pure single-phase equiaxed nanopowders of LaCoO₃ with crystal size of 20 nm, free of amorphous carbon and without the presence of polycrystalline aggregates.     

Response of storage molds to different initial moisture contents of maize (corn) stored at 25 °C, and effect on respiration rate and nutrient composition

Maize was stored for 2 months in chambers maintained at 25 °C to simulate conditions observed in the central part of the “Corn Belt” of the United States when the grain warms because of high summertime temperatures after a period of winter storage. Maize was brought to three moisture contents (m.c.) within the range typically observed in farm and commercial storage, and was inoculated to simulate the amount of storage mold contamination typical of this situation. Certain of the experimental units were packed in insulation so that heat could accumulate within the grain masses to simulate hot spots. The wettest grain heated rapidly and became semi-anaerobic. The hot grain then dried rapidly, with the amount of moisture loss influenced by the ratio of water vapor pressures inside and outside the grain. The hot grain cooled and became more aerobic over time. New infections by storage molds, disappearance of viable field molds, development of kernel damage, and changes in atmospheric gases within the grain masses were correlated with the grain moisture or temperature and the rate at which the moisture and temperature changed. The rate of increase in new kernel damage was as high as 3.3% per week. Both the rate of respiration and the estimated ratio of starch to fat consumed were associated with the mean grain m.c. during the trial, and the estimated ratio of starch to fat consumed was in the range of 2.2/1–2.6/1 in the grain containing 16.6–18.2% m.c. That both fat and starch were consumed calls into question loss estimates based on starch metabolism alone. The fat content of the grain decreased more than 10% in some experimental units, but increased less than 5% in others. The protein content generally increased as other grain constituents were consumed.     

Social contacts and production of 50-kHz short ultrasonic calls in adult rats.

The goal of the study was to provide evidence that the production of 50-kHz calls by adult rats is driven by potential or direct social contacts. The calls have been studied during daily visits to a cage by single or paired rats. Repeated exposure of rats to the cage frequently visited by other rats or direct contact between rats significantly increased the number of 50-kHz calls. The increase in production of 50-kHz calls was reduced by 78% after intrapreoptic-anterior hypothalamic injection of MK-801, an N-methyl-D-aspartate-type glutamate receptor antagonist. Calls emitted in all situations had a similar acoustic profile. It was found that 50-kHz calls were produced in anticipation of, and/or during, direct social contacts among adult rats and were predominantly initiated by olfactory stimuli. The calls seem to express an appetitive behavioral state in which the central glutamatergic mechanism is implicated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)