Two silicone nontoxic fouling release coatings: Hydrosilation cured PDMS and CaCO3 filled,ethoxysiloxane cured RTV11

Two silicone coatings have been evaluated for barnacle adhesion. One coating is an unfilled hydrosilation cured polydimethylsiloxane (PDMS) network, while the other is a room temperature vulcanized (RTV), filled, ethoxysiloxane cured PDMS elastomer, RTV11^?. The adhesion strength of one species of barnacle, Balanus eburneus, to the hydrosilation coatings is in the range of 0.37–0.60 kg cm^‐2 while the corresponding range for RTV11 is 0.64–0.90 kg cm^‐2. The easier release of B. eburneus from the hydrosilation cured network compared to RTV11 is discussed in relationship to differences in bulk and surface properties. Preliminary results suggest bulk modulus may be the most important parameter in determining barnacle adhesion strength. In light or mechanical property analysis, a re‐evaluation of surface properties and chemical stability is presented.     

Hyperphagia-mediated obesity in transgenic mice misexpressing the RNA-editing enzyme ADAR2

ADAR2 is a double-stranded RNA-specific adenosine deaminase involved in the editing of mammalian RNAs by the site-specific conversion of adenosine to inosine. To examine the physiologic consequences resulting from ADAR2 misexpression, we have generated mutant mice expressing either wild-type or deaminase-deficient ADAR2 transgenes under the control of the human cytomegalovirus promoter. Transgenic mice expressing either wild-type or inactive ADAR2 isoforms demonstrated adult onset obesity characterized by hyperglycemia, hyperleptinemia, and increased adiposity. Paired feeding analysis revealed that mutant mice on caloric restriction had a growth rate and body composition indistinguishable from wild-type littermates, indicating that the observed obesity predominantly results from hyperphagia rather than a metabolic derangement. The observation that expression of catalytically inactive ADAR2 also is capable of producing an obese phenotype in mutant animals suggests that ADAR2 may possess additional biological activities beyond those required for the site-selective deamination of adenosine or may interfere with the actions of other double-stranded RNA-specific binding proteins in the cell.     

The role of calcitonin and alpha-calcitonin gene-related peptide in bone formation

The Calca gene encodes two polypeptides, calcitonin (CT) and α-calcitonin gene-related peptide (α-CGRP), generated through alternative splicing. While CT, a hormone mainly produced by thyroidal C cells, has been described as a major regulator of bone resorption, α-CGRP, a neuropeptide expressed in the cells of the central and peripheral nervous system, is mostly known as a regulator of vascular tone. Surprisingly, the generation and skeletal analyses of two mouse deficiency models has recently uncovered a physiological function for both peptides in the regulation of bone formation. In the first model, where the replacement of exons 2-5 of the Calca gene resulted in the combined deficiency of CT and α-CGRP, an increased bone formation rate (BFR) was observed, whereas decreased BFR was found in the second model, where the introduction of a translational termination codon into exon 5 of the Calca gene resulted in the specific absence of α-CGRP.     

Synthesis,characterization, and electrocatalytic behaviour of hydrothermally grown nanostructured La2O3 and La2O3/K-complex

Rare earth metals play a conspicuous role in magnetic resonance imaging (MRI) for detecting cancerous cells. The alkali metal potassium is a neurotransmitter in the sodium–potassium pump in biomedical sciences. This unique property of rare earth metals and potassium drew our attention to carry forward this study. Therefore, in this work, previously synthesized potassium (K) complexes formed by the reflux of 4-N,N-dimethylaminobenzoic acid (DBA) and potassium hydroxide in methanol, and named [(μ2–4-N,N-dimethylaminobenzoate-κO)(μ2–4-N,N-dimethylaminobenzoic acid-κO)(4-N,N-dimethylaminobenzoic acid-κO) potassium(I) coordination polymer)] were treated hydrothermally with La₂O₃ nanomaterials to obtain a nanohybrid La₂O₃/K-complex. After that, the K-complex was analyzed using single-crystal X-ray diffraction and ¹H and ¹³C NMR spectroscopy. In addition, the structural and morphological properties of the as-prepared nanostructured La₂O₃/K-complex were also characterized, which involved an investigation using X-ray diffraction (XRD)spectroscopy, Fourier transform infrared (FTIR) spectroscopy, atomic force spectroscopy (AFM), transmission electron microscopy (TEM), and energy dispersive X-ray (EDX) analysis. After this, the electrochemical redox behaviour of the synthesized nanohybrid material was studied using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Therefore, the results from these studies revealed that the as-prepared material was a La₂O₃/K-complex that has a promising future role in sensing various analytes, as it showed effective electrocatalytic behaviour.     

Sex differences in the rate of fatigue development and recovery

Background

Many musculoskeltal injuries in the workplace have been attributed to the repetitive loading of muscle and soft tissues. It is not disputed that muscular fatigue is a risk factor for musculoskeltal injury, however the disparity between gender with respect to muscular fatigability and rate of recovery is not well understood. Current health and safety guidelines do not account for sex differences in fatiguability and may be predisposing one gender to greater risk. The purpose of this study was to quantify the sex differences in fatigue development and recovery rate of lower and upper body musculature after repeated bouts of sustained isometric contractions.

Methods

Twenty-seven healthy males (n = 12) and females (n = 15) underwent bilateral localized fatigue of either the knee extensors (male: n = 8; female: n = 8), elbow flexors (male: n = 8; female: n = 10), or both muscle groups. The fatigue protocol consisted of ten 30-second sub-maximal isometric contractions. The changes in maximum voluntary contraction (MVC), electrically evoked twitches, and motor unit activation (MUA) were assessed along with the ability to control the sustained contractions (SLP) during the fatigue protocol using a mixed four-factor repeated measures ANOVA (gender × side × muscle × time) design with significance set at p < 0.05.

Results

There was a significant loss of MVC, MUA, and evoked twitch amplitude from pre- to post-fatigue in both the arms and legs. Males had greater relative loss of isometric force, a higher rate of fatigue development, and were less capable of maintaining the fatiguing contractions in the legs when compared to the females.

Conclusion

The nature of the induced fatigue was a combination of central and peripheral fatigue that did not fully recover over a 45-minute period. The results appear to reflect sex differences that are peripheral, and partially support the muscle mass hypothesis for explaining differences in muscular fatigue.