Attractivity and social preferences in mice (Mus musculus domesticus): The role of prepubertal sexual segregation and of precocious weaning.

Mice (Mus musculus domesticus) were raised (Postnatal Day 15 to 25) in single- or mixed-sex litters and precociously (Day 15) or regularly (Day 25) weaned. When they were faced as adults with a basic social choice—between two stimulus mice raised in litters of different sex composition but both of the same sex as the chooser—mice raised in mixed-sex litters were preferred. In the sociosexual choice—between a male and a female, both from the single- or the mixed-sex group—the opposite-sex preference was expressed. Both these preferences were abolished by the sexual segregation of the choosers. This variable hardly affected potential mate choice—between two stimulus mice both of the opposite sex of the chooser but raised in litters of different sex composition. Data indicate that socially mediated behavioral plasticity has a major role in the early shaping of adult individual differences both in attractive stimulus properties and in sociosexual preferences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnesium fertilization has a greater impact on soil and leaf nutrient concentrations than nitrogen or calcium fertilization in Florida orange production

Nutrient Cycling in Agroecosystems - Citrus production has been declining in Florida since 2004, mainly because of Huanglongbing (HLB), a deadly disease that is affecting an increasingly large...     

Films made from polyethylene‐co‐acrylic acid and soluble biopolymers sourced from agricultural and municipal biowaste

Blends were obtained from polyethylene‐co‐acrylic acid (PEAA) with 248 kDa molecular weight and two water soluble biopolymers isolated from the hydrolysate of postharvest tomato plant and urban biowaste compost. The two hydrolysates were constituted respectively from a polysaccharide (SP) with 27 kDa molecular weight and a lignin‐like polymer (LP) with 75 kDa molecular weight containing aliphatic and aromatic C moieties substituted by carboxyl, hydroxyl, and amino groups. Evidence was obtained for reactions occurring between the biopolymers and the synthetic polymer leading to new polymers with 151 to 1243 kDa molecular weights. The thermal and mechanical properties of the blends were studied. Compared with neat PEAA, the PEAA‐LP blends containing 5 to 10% LP exhibited 2 to 5× higher molecular weights, 10 to 50% lower crystallinity, 2 to 6× higher Young's modulus, over 3× higher stress at yield point and somewhat lower strain at break (55–280% vs. over 300%). On the contrary the PEAA‐SP blends exhibited 6 to 13% lower crystallinity and the same mechanical properties as neat PEAA. The results offer scope for investigating biopolymers sourced from other biowastes to understand more the reasons of the observed effects and exploit their full potential to modify or to replace synthetic polymers. Perspectives of economic and environmental benefits are discussed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41909.     

Single-crystal organic charge-transfer interfaces probed using Schottky-gated heterostructures

Organic semiconductors based on small conjugated molecules generally behave as insulators when undoped, but the heterointerfaces of two such materials can show electrical conductivity as large as in a metal. Although charge transfer is commonly invoked to explain the phenomenon, the details of the process and the nature of the interfacial charge carriers remain largely unexplored. Here we use Schottky-gated heterostructures to probe the conducting layer at the interface between rubrene and PDIF-CN(2) single crystals. Gate-modulated conductivity measurements demonstrate that interfacial transport is due to electrons, whose mobility exhibits band-like behaviour from room temperature to ~150 K, and remains as high as ~1 cm(2) V(-1) s(-1) at 30 K for the best devices. The electron density decreases linearly with decreasing temperature, an observation that can be explained quantitatively on the basis of the heterostructure band diagram. These results elucidate the electronic structure of rubrene/PDIF-CN(2) interfaces and show the potential of Schottky-gated organic heterostructures for the investigation of transport in molecular semiconductors.     

SMART Silly Putty: Stretchable,Malleable, Adherable,Reusable, and Tear-Resistible Hydrogels

Cell engineering, soft robotics, and wearable electronics often desire soft materials that are easy to deform, self-heal readily, and can relax stress rapidly. Hydrogels, a type of hydrophilic networks, are such kind of materials that can be made responsive to environmental stimuli. However, conventional hydrogels often suffer from poor stretchability and repairability. Here, hydrogels consisting of boronic ester dynamic covalent bonds in a double network of poly(vinyl alcohol)/boric acid and chitosan are synthesized, which demonstrate extreme stretchability (up to 310 times the original length), instant self-healing (within 5 s), and reusability and inherent adhesion. Their instant stress relaxation stems from a low activation energy of the boronic ester bond exchange (≤20 kJ mol⁻¹) and contributes to the extreme stretchability and self-healing behaviors. Various water-dispersible additives can be readily incorporated in the hydrogels via hand kneading for potential applications such as soft electronics, bio-signal sensing, and soft artificial joints.     

New material for orthopedic implants: Electrochemical study of nickel free P558 stainless steel in minimum essential medium

Nickel, a component of stainless steels (SS) applied in orthopedic implants may cause allergic processes in human tissues. P558 nickel free SS was studied to verify its viability as a substitute for stainless steel containing nickel. Its performance is compared to ISO 5832-9 and F138 most used nowadays grades in implants fabrications, in minimum essential medium, MEM, at 37 °C. Potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and “in vitro” cytotoxicity were used as techniques. From the electrochemical point of view P558 SS is comparable to ISO 5832-9 SS in MEM. It remains passivated until the transpassivation potential, above which generalized corrosion occurs. F138 presents pitting corrosion at 370 mV/SCE. The cytotoxicity results showed that P558, ISO 5832-9 and F138 do not present cytotoxic character. Therefore, these results suggest that P558 SS can be applied in orthopedic implants.     

New insight about the relationship between the main characteristics of precursor materials and activated carbon properties using multivariate analysis

Agro-industrial wastes are used as carbon precursors in the production of activated carbon because they are rich in lignocellulosic materials. This study aimed to investigate the relationship between the main characteristics of precursor materials and activated carbons by multivariate analysis. After characterization of the precursor materials and their respective carbons, the principal component analysis and canonical correlation analysis were performed. Materials with cellulose/lignin ratio > 3.0 led to the production of carbons with a higher pore diameter, while materials with a cellulose/lignin ratio ≤ 1.0 led to a low pore volume. Using the mathematical models obtained, it is possible to predict the carbon characteristics using only the composition data of the lignocellulosic materials.