Venous blood gases and electrolyte values of captive red foot tortoise (Chelonoidis carbonarius).

Blood gas analysis reflects the exchange of oxygen and carbon dioxide in the lungs. This test provides important information, since the relationship between these gases has a direct impact on the acid-basic balance in the body. Given the significance of blood gas analysis in Brazilian reptiles, this study set out to establish temperature-corrected and uncorrected reference intervals for venous blood gas measurements in Chelonoidis carbonarius, and to compare values between females and males. In this study, 19 animals were used, 8 males and 11 females. Blood samples were collected from the dorsal coccygeal vein, and the analyses were performed immediately after blood sample collection. The following parameters were measured: pH, PO2, HCO3-, TCO2, BEecf, Na, K, ICa, and Glu, and were compared between females and males. Additionally, pH, pCO2, and pO2 values were compared with and without temperature correction. Oxygen saturation and Na levels were significantly higher (p<0.05) in males. Furthermore, it was possible to infer that the lower the body temperature relative to the environmental temperature, the larger the difference in pH following temperature correction.

Assessing the Long-Term Performance of Adhesive Joints in Space Structures during Interplanetary Exploration.

Spacecraft experience minimal mechanical loads in space, but with the development of reusable spacecraft for interplanetary exploration and repeated landings, structures will be subjected to increased mechanical stress. The impact of the space environment on the aging of adhesive materials used in space structures over long-term applications is not well understood. This study investigates two commonly used adhesives in spacecraft assembly, namely Scotch-Weld™ EC-2216 and Scotch-Weld™ EC-9323-2, under two aging conditions: (1) high-energy electron irradiation using a Van de Graaf accelerator, and (2) thermal vacuum cycling. The research evaluates the evolution of intrinsic adhesive properties and adhesion to CFRP (carbon fiber-reinforced polymer) and aluminum adherents before and after exposure to these environmental conditions through tensile tests, peel tests, double-cantilever beam (DCB) tests, and dynamic mechanical analysis (DMA).

Breaking-Up Sedentary Behavior and Detraining Effects on Glycemic Control: A Randomized Crossover Trial in Trained Older Adults.

In a randomized crossover trial, we examined the effects of interrupting sedentary behavior on glycemic control in trained older adults, before and after 2 weeks of detraining. Fourteen participants (65-90 years old) completed two 7-hr conditions before and after 2 weeks of detraining: (a) uninterrupted sitting (SIT) and (b) sitting plus 2 min of moderate-intensity activity every 30 min (INT). Both before and after detraining, no differences were observed for 7-hr glucose area under the curve (7 hr AUC) and mean glucose between sitting plus 2 min of moderate-intensity activity and uninterrupted sitting conditions. After detraining and for the SIT condition, higher values of 7-hr AUC (p = .014) and mean glucose (p = .015) were observed, indicating worsened glycemic control. No changes were observed in INT condition between both time points. Frequent interruptions in sedentary behavior had no effect on glycemic control, prior to or after detraining. Even so, older adults experiencing a short-term detraining period should avoid prolonged bouts of sedentary behavior that may jeopardize their glycemic control.

The impact of 2 weeks of detraining on phase angle, BIVA patterns, and muscle strength in trained older adults.

BACKGROUND: An intermission in the training routine, in which older adults refrain from regular structured exercise, may have deleterious effects on muscle performance and bioelectric phase angle (PhA), which is a predictive marker for cellular integrity. PURPOSE: To determine the effects of a 2-week detraining period on PhA and muscular strength (MS) in trained older adults. METHODS: A total of 14 trained older adults (6 females) aged ≥65 years (77.2 ± 6.6) were assessed at baseline (i.e. trained condition) and after 2 weeks of detraining, where they refrained from their usual participation in structured exercise sessions. Whole-body resistance (R), reactance (Xc), and PhA were assessed using bioelectrical impedance analysis (BIA, single frequency, 50 kHz ± 1%, NutriLab, Akern). MS was assessed on both lower and upper limbs under isometric conditions. Differences between moments were examined using ANOVA for repeated measures, while adjusting for sex. Bioimpedance vector analysis (BIVA) was performed to evaluate changes in cellular function and body fluid content. RESULTS: Detraining resulted in declines in PhA (-4.34%) (p = 0.017). There was a significant difference in the mean impedance vectors from baseline to post-detraining (p < 0.05), which were driven by decreases in reactance (Xc) relative to height (Xc/H) with little change in resistance (R) relative to height (R/H) for both males and females. No differences were found in MS for both the leg press (p = 0.992) and bench press (p = 0.166) tests. CONCLUSION: A detraining period as short as 2-weeks is enough to cause alterations in the bodies bioelectrical properties, resulting in detrimental changes in PhA, due to alterations in cellular integrity, but not in MS. These results highlight the importance of maintaining structured exercise sessions in older adults, and reinforce the potential role of PhA as a sensitive predictor to detect acute changes in muscle cell integrity following alterations in exercise training.

Review on Adhesives and Surface Treatments for Structural Applications: Recent Developments on Sustainability and Implementation for Metal and Composite Substrates.

Using adhesives for connection technology has many benefits. It is cost-efficient, fast, and allows homogeneous stress distribution between the bonded surfaces. This paper gives an overview on the current state of knowledge regarding the technologically important area of adhesive materials, as well as on emergent related technologies. It is expected to fill some of the technological gaps between the existing literature and industrial reality, by focusing at opportunities and challenges in the adhesives sector, on sustainable and eco-friendly chemistries that enable bio-derived adhesives, recycling and debonding, as well as giving a brief overview on the surface treatment approaches involved in the adhesive application process, with major focus on metal and polymer matrix composites. Finally, some thoughts on the connection between research and development (R&D) efforts, industry standards and regulatory aspects are given. It contributes to bridge the gap between industry and research institutes/academy. Examples from the aeronautics industry are often used since many technological advances in this industry are innovation precursors for other industries. This paper is mainly addressed to chemists, materials scientists, materials engineers, and decision-makers.

Enhanced Interface Adhesion by Novel Eco-Epoxy Adhesives Based on the Modified Tannic Acid on Al and CFRP Adherends.

This paper presents a new process for obtaining eco-epoxide adhesives synthesized from bio-renewable raw material (tannic acid-TA) and used for bonding lightweight materials (aluminum (Al) and carbon fiber reinforced polymer (CFRP)). Two synthesized bio-epoxy components based on TA, (A) glycidyl ether and (B) glycidyl phosphate ester of TA, were used as a replacement for the toxic epoxy component based on Bisphenol A. The effect of eco-epoxy components on the interface adhesion was measured by the determination of adhesion parameter b, which was compared to the reference epoxy (REF). The increase of adhesion parameter b was 77.5% for A and 151.5% for B. The adhesion of both eco-adhesives was tested using the bell peel test (BPT) with the Al and CFRP adherends. When compared to REF, the average peel load for B was 17.6% (39.3%) and 58.3% (176.9%) higher for the Al and CFRP adherends, respectively. Complete adhesion failure of REF reflected the weak adhesion to both Al and CFRP, which was improved by the addition of eco-epoxy components A and B showing the presence of cohesive failure. The microhardness testing method of interface adhesion was proven to be a fast and reliable testing method, providing a qualitative indication in adhesive selection.

Out-of-autoclave manufacturing of GLARE panels using resistance heating.

Autoclave manufacturing of fibre metal laminates, such as GLARE, is an expensive process. Therefore, there is an increasing interest to find cost-effective out-of-autoclave manufacturing processes without diminishing the laminate quality. The aim of this study is to evaluate the quality of fibre metal laminate panels adhesively bonded and cured using resistance heating. Three manufacturing processes are compared for different layups with an embedded steel mesh at the mid-plane: autoclave curing, resistance bonding of two (autoclave-cured) panels and complete out-of-autoclave resistance curing of panels. Interlaminar shear strength tests and optical microscopy analysis showed that resistance bonding is a promising technique, leading to results comparable to autoclave curing. Resistance curing led to an interlaminar shear strength decrease of 30-60%. A study of the correlation between degree of cure and distance from the mesh revealed the potential of resistance bonding to be used for flexible embedded mesh geometries and on-site repairs.

Effects of trampling on morphological and mechanical traits of dryland shrub species do not depend on water availability.

In semiarid drylands water shortage and trampling by large herbivores are two factors limiting plant growth and distribution. Trampling can strongly affect plant performance, but little is known about responses of morphological and mechanical traits of woody plants to trampling and their possible interaction with water availability. Seedlings of four shrubs (Caragana intermedia, Cynanchum komarovi, Hedysarum laeve and Hippophae rhamnoides) common in the semiarid Mu Us Sandland were grown at 4% and 10% soil water content and exposed to either simulated trampling or not. Growth, morphological and mechanical traits were measured. Trampling decreased vertical height and increased basal diameter and stem resistance to bending and rupture (as indicated by the increased minimum bend and break force) in all species. Increasing water availability increased biomass, stem length, basal diameter, leaf thickness and rigidity of stems in all species except C. komarovii. However, there were no interactive effects of trampling and water content on any of these traits among species except for minimum bend force and the ratio between stem resistance to rupture and bending. Overall shrub species have a high degree of trampling resistance by morphological and mechanical modifications, and the effects of trampling do not depend on water availability. However, the increasing water availability can also affect trade-off between stem strength and flexibility caused by trampling, which differs among species. Water plays an important role not only in growth but also in trampling adaptation in drylands.

Nephrotoxicity of hexachloro-1:3-butadiene in the male Hanover Wistar rat; correlation of minimal histopathological changes with biomarkers of renal injury.

Hexachloro-1:3-butadiene (HCBD) causes damage specifically to the renal proximal tubule in rats. In the present study, injury to the nephron of male Hanover Wistar rats was characterized at 24 h following dosing with HCBD in the range 5-90 mg kg⁻¹ to determine the most sensitive biomarkers of damage, that is, the biomarkers demonstrating significant changes at the lowest dose of HCBD, using a range of measurements in serum and urine, renal histopathology, and renal and hepatic gene expression. Histologically, kidney degeneration was noted at doses as low as 10 mg kg⁻¹ HCBD. Significant changes in the hepatic and renal gene expression categories of xenobiotic metabolism and oxidative stress were observed at 5 mg kg⁻¹ HCBD, and in the kidney alone, evidence of inflammation at 90 mg kg⁻¹ HCBD. Increases in the urinary excretion of α-glutathione S-transferase (α-GST) and kidney injury molecule-1 (KIM-1) were seen at 10 mg kg⁻¹ HCBD, and increases in urinary excretion of albumin and total protein were evident at 15 mg kg⁻¹ HCBD. The most sensitive, noninvasive biomarkers of HCBD-induced renal toxicity in Hanover Wistar rats were urinary α-GST and KIM-1. Urinary albumin measurement is also recommended as, although it is not the most sensitive biomarker, together with α-GST, albumin showed the largest relative increase of all the biomarkers investigated, and the protein is easily measured.

Corynebacterium glutamicum survives arsenic stress with arsenate reductases coupled to two distinct redox mechanisms.

Arsenate reductases (ArsCs) evolved independently as a defence mechanism against toxic arsenate. In the genome of Corynebacterium glutamicum, there are two arsenic resistance operons (ars1 and ars2) and four potential genes coding for arsenate reductases (Cg_ArsC1, Cg_ArsC2, Cg_ArsC1' and Cg_ArsC4). Using knockout mutants, in vitro reconstitution of redox pathways, arsenic measurements and enzyme kinetics, we show that a single organism has two different classes of arsenate reductases. Cg_ArsC1 and Cg_ArsC2 are single-cysteine monomeric enzymes coupled to the mycothiol/mycoredoxin redox pathway using a mycothiol transferase mechanism. In contrast, Cg_ArsC1' is a three-cysteine containing homodimer that uses a reduction mechanism linked to the thioredoxin pathway with a k(cat)/K(M) value which is 10(3) times higher than the one of Cg_ArsC1 or Cg_ArsC2. Cg_ArsC1' is constitutively expressed at low levels using its own promoter site. It reduces arsenate to arsenite that can then induce the expression of Cg_ArsC1 and Cg_ArsC2. We also solved the X-ray structures of Cg_ArsC1' and Cg_ArsC2. Both enzymes have a typical low-molecular-weight protein tyrosine phosphatases-I fold with a conserved oxyanion binding site. Moreover, Cg_ArsC1' is unique in bearing an N-terminal three-helical bundle that interacts with the active site of the other chain in the dimeric interface.