Effect of a training week on heart rate variability in elite youth rugby league players.

The aim of this study was to examine the influence of weekly training including a competitive game on heart rate (HR) variability (HRV). Youth players (n=9, age 17-20 years) were monitored during daily supine rest (10 min) and standing (8 min), 5 times over 8 days. Heart rate recordings were analysed for time domain, frequency (e. g. low frequency [LF], high frequency [HF]) domain and non-linear measures of HRV and compared using ANOVA or Friedman's tests. Relationships between HRV and training workloads were examined via Spearman rank rho (ρ) correlation coefficients. Prior to a game, mean HR was significantly increased and remained elevated until 2 days post-game while parasympathetic modulations (HF) were significantly reduced (p<0.05). The supine to standing change in HRV was significantly reduced for up to 4 days post-game (LF/HF ratio, - 1.0±2.9 vs. - 3.0±1.9, p<0.05). These results confirm that prior to a game, players exhibited reduced parasympathetic and/or predominant sympathetic modulation with the game significantly reducing autonomic responses to standing for up to the following 4 days. Identification of day to day fluctuations in HRV may provide a helpful tool for monitoring player workload to maximise training and game performance.

Mercury distribution across 14 U.S. Forests. Part I: spatial patterns of concentrations in biomass, litter, and soils.

Results from a systematic investigation of mercury (Hg) concentrations across 14 forest sites in the United States show highest concentrations in litter layers, strongly enriched in Hg compared to aboveground tissues and indicative of substantial postdepositional sorption of Hg. Soil Hg concentrations were lower than in litter, with highest concentrations in surface soils. Aboveground tissues showed no detectable spatial patterns, likely due to 17 different tree species present across sites. Litter and soil Hg concentrations positively correlated with carbon (C), latitude, precipitation, and clay (in soil), which together explained up to 94% of concentration variability. We observed strong latitudinal increases in Hg in soils and litter, in contrast to inverse latitudinal gradients of atmospheric deposition measures. Soil and litter Hg concentrations were closely linked to C contents, consistent with well-known associations between organic matter and Hg, and we propose that C also shapes distribution of Hg in forests at continental scales. The consistent link between C and Hg distribution may reflect a long-term legacy whereby old, C-rich soil and litter layers sequester atmospheric Hg depositions over long time periods. Based on a multiregression model, we present a distribution map of Hg concentrations in surface soils of the United States.

Optimization of a novel enzyme treatment process for early-stage processing of sheepskins.

An enzyme treatment process for early-stage processing of sheepskins has been previously reported by the Leather and Shoe Research Association of New Zealand (LASRA) as an alternative to current industry operations. The newly developed process had marked benefits over conventional processing in terms of a lowered energy usage (73%), processing time (47%) as well as water use (49%), but had been developed as a "proof of principle''. The objective of this work was to develop the process further to a stage ready for adoption by industry. Mass balancing was used to investigate potential modifications for the process based on the understanding developed from a detailed analysis of preliminary design trials. Results showed that a configuration utilising a 2 stage counter-current system for the washing stages and segregation and recycling of enzyme float prior to dilution in the neutralization stage was a significant improvement. Benefits over conventional processing include a reduction of residual TDS by 50% at the washing stages and 70% savings on water use overall. Benefits over the un-optimized LASRA process are reduction of solids in product after enzyme treatment and neutralization stages by 30%, additional water savings of 21%, as well as 10% savings of enzyme usage.

Effect of collagen packing and moisture content on leather stiffness.

Applications for skin derived collagen materials, such as leather and acellular dermal matrices, usually require both strength and flexibility. In general, both the tensile modulus (which has an impact on flexibility) and strength are known to increase with fiber alignment, in the tensile direction, for practically all collagen-based tissues. The structural basis for flexibility in leather was investigated and the moisture content was varied. Small angle X-ray scattering was used to determine collagen fibril orientation, elongation and lateral intermolecular spacing in leather conditioned by different controlled humidity environments. Flexibility was measured by a three point bending test. Leather was prepared by tanning under biaxial loading to create leather with increased fibril alignment and thus strength, but this treatment also increased the stiffness. As collagen aligns, it not only strengthens the material but it also stiffens because tensile loading is then applied along the covalent chain of the collagen molecules, rather than at an angle to it. Here it has been shown that with higher moisture content greater flexibility of the material develops as water absorption inside collagen fibrils produces a larger lateral spacing between collagen molecules. It is suggested that water provides a lubricating effect in collagen fibrils, enabling greater freedom of movement and therefore greater flexibility. When collagen molecules align in the strain direction during tanning, leather stiffens not only by the fiber alignment itself but also because collagen molecules pack closer together, reducing the ability of the molecules to move relative to each other.

Data on collagen structures in leather with varying moisture contents from small angle X-ray scattering and three point bend testing.

The data presented in this article are related to the research article entitled "Effect of collagen packing and moisture content on leather stiffness" (Kelly et al., 2018). This article describes how moisture content affects collagen packing and leather stiffness. Structural changes were experimentally introduced into ovine leather through biaxial strain during tanning (׳stretch tanning׳). Leather samples produced normally without strain (׳non-stretch tanned׳) and those produced by stretch tanning, were conditioned in a range of relative humidity environments and then analysed by small angle X-ray scattering and three point bend testing. The collagen D-spacing, lateral intermolecular spacing and flexural properties were measured under these varying moisture contents.

Influence of commonly used pharmaceutical agents on equine bone marrow-derived mesenchymal stem cell viability.

REASON FOR PERFORMING STUDY: To provide evidence to support recommendations regarding the co-administration of drugs with mesenchymal stem cell (MSC) therapy. OBJECTIVES: To determine the influence of sedatives, local anaesthetic and corticosteroids on MSC viability and proliferation, in comparison to somatic cells derived from tendon (TDCs). STUDY DESIGN: In vitro cell culture. MATERIALS AND METHODS: MSCs (n = 3) and TDCs (n = 2) were cultured in media containing a clinically relevant dose range of xylazine, romifidine, detomidine and butorphanol, mepivacaine, methylprednisolone, or triamcinolone acetonide. Cell viability in suspension culture was assessed at intervals up to 4 h using the trypan blue dye assay. MSCs in monolayer culture were exposed to the highest concentrations of drug and proliferation was measured using the alamarBlue fluorescence assay. RESULTS: Exposure to romifidine or mepivacaine did not significantly affect viability or proliferation rate of MSCs or TDCs at any of the dosages tested. At the highest concentration of detomidine and butorphanol, MSC viability was significantly reduced compared to controls. Although xylazine exposure caused a significant (P < 0.001), dose-dependent reduction in MSC viability compared to controls, overall population viability remained good. Conversely, both methylprednisolone and triamcinolone resulted in the rapid death of significant numbers of MSCs (P < 0.001). CONCLUSIONS: Clinicians can sedate horses and administer nerve blocks to assist in intratendinous or intrathecal injection of MSCs with confidence that these drugs will not impact the viability of implanted cells. However, the concomitant use of corticosteroids is likely to have a severely detrimental effect on cell viability and should not be performed. Similarly, steroid administration into the sheath of a damaged tendon is not recommended.

Alterations in phosphatidylcholine species and their reversal in pulmonary surfactant during essential fatty-acid deficiency.

Previous studies (Kyriakides, E.C., Beeler, D.A. and Balint, J.A. (1974) Clin. Res. 22, 717a, and Burnell, J.M. and Balint, J.A. (1975) Fed. Proc. 34, 426) have indicated that essential fatty-acid deficiency in rats resulted in significant reduction of palmitate content of lung tissue and lavage phosphatidylcholines. Experiments were, therefore, undertaken to confirm and further characterize these changes and to examine the reversal of these alterations when essential fatty acid deficient rats were fed fat-free diets supplemented with linoleate for 1-14 days. Analysis of the fatty acid composition of liver lipids was used to confirm the presence of essential fatty-acid deficiency in rats that were fed a fat-free diet supplemented with 4% by weight of tripalmitoylglycerol for 14 weeks. Phosphatidylcholines from lung tissue and lavage fluid of essential fatty-acid deficient rats contained significantly less palmitate and significantly more palmitoleate and oleate than those rats receiving linoleate. These changes in fatty acid composition were reflected in a significant reduction of disaturated phosphatidylcholines (predominantly dipalmitoyl) in lung tissue and lavage fluid from essential fatty-acid deficient rats, while the total phosphatidylcholine content remained unchanged. On feeding the diet containing linoleate to the deficient rats, a reversal of these changes began after one day and was nearly complete by 7-14 days.

Cellular proliferation and renewal in the various zones of the hamster epididymis after colchicine administration.

Cellular proliferation was examined in the various regions of the excurrent ducts of the reproductive system of the male golden hamster after colchicine administration. Each of the two zones of the ductuli efferentes displayed only infrequent mitotic figures. Similarly, the basal cell population of the epididymis as well as the epithelium of the vas deferens exhibited too few mitotic figures to allow meaningful evaluation of cellular proliferation. The following observations were reported. 1. The principal cells of the entire epididymis are characterized by a singular diurnal cycle of proliferative activity reaching its maximum about 3 P.M. and its nadir about 9 A.M. 2. A circadian rhythm of cell division is also found in the principal cells of each of the six zones of the epididymis, although the time of maximal activity may vary from zone to zone. 3. The most actively proliferating region of the excurrent duct system is zone 3 of the epididymis, whereas the least active region is the ductuli efferentes. 4. The renewal rates of the principal cells vary considerably at various points along the excurrent duct system, ranging from cells which renew themselves as many as 10 times to cells which fail to renew themselves at all during the normal life-span of the animal.

Cough with green sputum.

Good treatment often involves advice on lifestyle modification which may be more important in the long run than pharmacological intervention alone. Compliance, however, is always a problem. Some patients refuse to take responsibility for their own health but repeatedly present to the GP to be patched up. The persistent smoker with recurrent bronchitis is just such a patient, but what can the conscientious GP do?

Collagen fibril orientation and tear strength across ovine skins.

Variability of physical properties across hides and skins requires careful consideration when manufacturing goods from leather. Therefore, an understanding of the extent of this variation and its nanostructural basis is useful. Tear strength tests were performed on ovine leather from a grid of 81 positions on skins. Synchrotron small-angle X-ray scattering measurements were made from three positions on the skin, from 26 skins. The X-ray structural measurements are compared with tear strengths of the samples. It is found that the thickness normalized tear strength does not vary greatly between different positions on the skin, in contrast to bovine hides. There is more variation between different skins than within the same skin. The collagen fibril orientation and orientation index, which has previously been shown to be correlated with tear strength, do not vary significantly between the different sampling positions in ovine skins. The collagen fibril orientation varies through the thickness of the skin in a consistent way. The consistency of collagen orientation in ovine leather between different positions on the skin is in marked contrast to bovine hides and informs the use of ovine leather for manufacturing applications.

Does proximity to mature trees influence ectomycorrhizal fungus communities of Douglas-fir seedlings?

The influence of mature trees on colonization of Douglas-fir (Pseudotsuga menziesii) seedlings by ectomycorrhizal fungi (EMF) is not well understood. Here, the EMF communities of seedlings planted near and far from trees are compared with each other, with EMF of seedlings potted in field soils and with EMF of mature trees. Seedlings were planted within 6 m, or beyond 16 m, from residual Douglas-fir trees in recently harvested green-tree retention units in Washington State, USA, or potted in soils gathered from near each residual tree. Mature tree roots were sampled by partly excavating the root system. The EMF communities were assessed by polymerase chain reaction-restriction fragment length polymorphism and sequence analysis of ribosomal RNA genes. Seedlings near trees had higher species richness and diversity of EMF communities compared with seedlings far from trees. The EMF communities of seedlings near trees were more similar to those of mature trees, while seedlings far from trees were more similar to glasshouse seedlings. By enhancing the EMF diversity of seedlings, residual trees may maintain or accelerate the re-establishment of mycorrhizal communities associated with mature forests.

Survival of coliform bacteria in sewage sludge applied to a forest clearcut and potential movement into groundwater.

Anaerobically digested dewatered sludge (10 to 15 cm thick) was applied to a forest clearcut as a fertilizer source in northwest Washington on gravelly glacial outwash soil. This sludge is not microbiologically sterile and may contain pathogenic organisms. Fecal coliform bacterial counts in sludge applied in summer (July) fell from 1.08 X 10(5) to 358/g in 204 days and to 0/g in 267 days. Dieoff appeared more rapid in winter (January)-applied sludge, when colnts fell from 1.2 X 10(5) to 20/g in 162 days. Initial death rates were related to sludge temperature, moisture, pH, physical composition, and microbial competition. Aftergrowth of fecal coliforms occurred in warm summer and fall months, but counts were of similar magnitude to background levels in forest soils, where a maximum count of 54/g was recorded. Total coliform counts in fresh sludge ranged from 1.4 X 10(4) to 1.9 X 10(6)/g. Numbers stabilized at 10(3) to 10(4)/g in spring, fall, and summer, with lower numbers in winter. Both total and fecal bacteria moved from the sludge to the soil beneath, but few penetrated past the first 5 cm. The soil acts as an effective biological filter. Few fecal coliform bacteria were recorded in the groundwater, generally being less than 5/100 ml and mostly 0/100 ml. A maximum count of 52/100 ml was recorded. Groundwater contamination from vertical movement of potential pathogens appears unlikely, but hazards from surface runoff and direct handling in the first year may arise.

Coliform aerosols generated from the surface of dewatered sewage applied to a forest clearcut.

Concentrations of airborne coliform bacteria as high as 1.5 X 10(4) m-3 were observed 8 cm above anaerobically digested sewage sludge applied to a forest clearcut. Dry conditions and high wind speeds tended to favor aerosol generation.