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The N-terminal region of troponin T (TnT) does not bind any protein of the contractile machinery and the role of its hypervariability remains uncertain. In this review we report the evidence of the interaction between TnT and AMP deaminase (AMPD), a regulated zinc enzyme localized on the myofibril. In periods of intense muscular activity, a decrease in the ATP/ADP ratio, together with a decrease in the tissue pH, is the stimulus for the activation of the enzyme that deaminating AMP to IMP and NH3 displaces the myokinase reaction towards the formation of ATP. In skeletal muscle subjected to strong tetanic contractions, a calpain-like proteolytic activity produces the removal in vivo of a 97-residue N-terminal fragment from the enzyme that becomes desensitized towards the inhibition by ATP, leading to an unrestrained production of NH3. When a 95-residue N-terminal fragment is removed from AMPD by trypsin, simulating in vitro the calpain action, rabbit fast TnT or its phosphorylated 50-residue N-terminal peptide binds AMPD restoring the inhibition by ATP. Taking in consideration that the N-terminus of TnT expressed in human as well as rabbit white muscle contains a zinc-binding motif, we suggest that TnT might mimic the regulatory action of the inhibitory N-terminal domain of AMPD due to the presence of a zinc ion connecting the N-terminal and C-terminal regions of the enzyme, indicating that the two proteins might physiologically associate to modulate muscle contraction and ammonia production in fast-twitching muscle under strenuous conditions.

Supramolecular peptides exhibit obvious similarities with collagen fibers in terms of self-assembly characteristics, nanofibrous structure, and responsiveness to external stimuli. Here, a series of supramolecular peptides were developed by altering the amino acid sequence, enabling the self-assembly of three types of 4-biphenylacetic acid (BPAA)-tripeptides into fibrous hydrogel through hydrogen bonding and π–π stacking under the influence of ion induction. Transmission electron and scanning electron microscopies revealed that the diameter of the fiber within nanofibrous hydrogels was ~ 10 and ~ 40 nm, respectively, which was similar with the self-assembled collagen fibers. For this reason, these hydrogels could be considered as a biomimetic extracellular substitute. Meanwhile, the gelation concentration induced by ions was even lower than 0.66 wt%, with an elastic modulus of ~ 0.27 kPa, corresponding to a water content of 99.34 wt%. In addition, the three supramolecular hydrogels were found to be good substrates for L929 cell adhesion and MC-3T3 cell proliferation. The overall results implied that BPAA-based hydrogels have a lucrative application potential as cell carriers. Graphical Abstract

In tissue engineering, bioactive materials play an important role, providing structural support, cell regulation and establishing a suitable microenvironment to promote tissue regeneration. As the main component of extracellular matrix, collagen is an important natural bioactive material and it has been widely used in scientific research and clinical applications. Collagen is available from a wide range of animal origin, it can be produced by synthesis or through recombinant protein production systems. The use of pure collagen has inherent disadvantages in terms of physico-chemical properties. For this reason, a processed collagen in different ways can better match the specific requirements as biomaterial for tissue repair. Here, collagen may be used in bone/cartilage regeneration, skin regeneration, cardiovascular repair and other fields, by following different processing methods, including cross-linked collagen, complex, structured collagen, mineralized collagen, carrier and other forms, promoting the development of tissue engineering. This review summarizes a wide range of applications of collagen-based biomaterials and their recent progress in several tissue regeneration fields. Furthermore, the application prospect of bioactive materials based on collagen was outlooked, aiming at inspiring more new progress and advancements in tissue engineering research. Graphical Abstract

The frequency of total knee arthroplasty (TKA) is increasing, particularly in younger and more active patients. In these patients, there may be greater functional demands, with an expectation to return to sporting activities (RTS) following TKA. There is a paucity of data on the time to RTS following TKA and the aim of this meta-analysis is to determine the time to RTS following TKA. Using the PRISMA guidelines, an electronic search of PUBMED, MEDLINE, EMBASE, and the Cochrane Library for trails was performed on TKA and RTS in English language, published since the inception of the database to 31st October 2020. Data evaluating the time to RTS and functional outcomes were recorded by two authors independently that were included in the analysis. Pooled analysis using random effect model on overall proportions at the different time intervals and at the end of the follow-up was carried out for all studies. In total, 1,611 studies were retrieved from literature search. Of these, nine studies met the inclusion criteria with 1,307 patients. Two studies with 148 patients demonstrated an overall pooled proportion of 18.7% (95% CI 8.2–32.3%) of patients RTS at 3 month post-TKA; Three studies reported RTS rate at 6 months 70.% (95% CI 48–88.4). Two studies with 123 patients demonstrated an overall pooled proportion of 84.0% (95% CI 77.1–89.9%) patients RTS at 12 months. 986 patients returned to sport from total of 1307, with an overall adjusted proportion return to sport of 87.9 (95% CI 80.5–93.8%) at the end of follow-up; mean 14 months (range 3–36 months). Patients undergoing TKA were found to successfully RTS, pooled proportion analysis showed an increasing rate of RTS with time, at a mean of 14 months following TKA, where 87.9% of patients had returned to sports. The findings of this study will enable more informed discussions and rehabilitation planning between patients and clinicians on RTS following TKA.

Despite calls for more attention to the preparation of those who prepare teachers, there have been few examples of institutionally sanctioned and structured learning opportunities created to equip faculty with the knowledge and skills necessary to become effective teacher educators. In this paper, we describe a cross-disciplinary and collaborative initiative that involves shadowing of colleagues as a means of supporting the professional learning of science teacher educators. We illustrate the unique affordance of this model and highlight our professional learning across multiple dimensions: cognitive, practical, relational, and emotional. We illustrate how shadowing can support the learning of faculty at different career stages and from different disciplinary backgrounds and entry points to teacher education through a series of vignettes of shadowing in a variety of course contexts. Finally, we offer considerations for the transferability of our model to other institutions and contexts, and how further research conducted in the context of shadowing could help deepen our understanding of the knowledge base of science teacher educators and how this knowledge is developed.

The aim of this research is to present a method to evaluate the X-ray attenuation coefficient of (nano)particles by uniformly dispersing them in a host polymer, polydimethylsiloxane. The method is described and applied to the case of a material of interest for medical application in X-ray shielding and imaging, namely bismuth oxychloride nanoplates (BiOCl NP). A diagnostic X-ray machine was used to perform X-ray attenuation tests. A certified copper plate was used for calibration purposes and to find the X-ray photon energy. Blank polymer and composites were investigated, and the attenuation coefficient μ and the mass attenuation coefficient μ/ρ of BiOCl NPs were found to be 45 cm−1 and 6 cm2 g−1, respectively. Based on these values, a discussion is presented in which the perspective applications of BiOCl in medicine are discussed with specific focus on (i) X-ray shielding and (ii) X-ray imaging.

Background Although general practitioners (GPs) are generally considered as the first point of contact for care, this may be different for persons with complex conditions, such as those with spinal cord injury (SCI). The objective of this study is to understand the differences in long-term care provision by GPs and SCI-specialists, by examining (1) the first contact of care for SCI health problems, (2) the morbidity profile and use of health-care services in relation to first contact, and (3) the factors associated with the choice of first contact. Methods In this cross-sectional study based on data derived from the Swiss Spinal Cord Injury Cohort Study Community Survey 2017, the main outcome measure was the reported first contact for SCI-specific care. This information was analysed using the chi-square test and logistic regression analysis of groups based on patient characteristics, use of health-care services and secondary health conditions assessed using the Spinal Cord Injury Secondary Conditions Scale (SCI-SCS). Results Out of 1294 respondents, 1095 reported their first contact for SCI-specific care; 56% indicated SCI-specialists and 44% specified GPs. On average, participants who first contacted a GP reported higher number of GP consultations (5.1 ± 5.2 vs. 3.9 ± 7.2), planned visits to ambulatory clinics (3.7 ± 7.3 vs. 3.6 ± 6.7) and hospital admissions (GP, 1.9 ± 1.7 vs. 1.5 ± 1.3), but lower number of visits to SCI-specialists (1.7 ± 1.8 vs. 2.6 ± 1.7) and of hospital days (22.8 ± 43.2 vs. 31.0 ± 42.8). The likelihood to contact a GP first was significantly higher in persons ≥75 years old (OR = 4.44, 95% CI = 1.85–10.69), Italian speakers (OR = 5.06, 95% CI = 2.44–10.47), had incomplete lesions (OR = 2.39, 95% CI = 1.71–3.35), experiencing pain (OR = 1.47, 95% CI = 1.04–2.09) or diabetes mellitus (OR = 1.85, 95% CI = 1.05–3.27), but lower for those situated closer to SCI centres (OR = 0.69, 95% CI = 0.51–0.93) or had higher SCI-SCS scores (OR = 0.92, 95% CI = 0.86–0.99). Conclusion Age, language region, travel distance to SCI centres, lesion completeness, and occurrence of secondary conditions play a significant role in determining the choice of first contact of care, however there is still some unwarranted variation that remains unclear and requires further research.

Isolation on Earth can alter physiology and signaling of organs systems, including the central nervous system. Although not in complete solitude, astronauts operate in an isolated environment during spaceflight. In this study, we determined the effects of isolation and simulated microgravity solely or combined, on the inflammatory cytokine milieu of the hippocampus. Adult female wild-type mice underwent simulated microgravity by hindlimb unloading for 30 days in single or social (paired) housing. In hippocampus, simulated microgravity and isolation each regulate a discrete repertoire of cytokines associated with inflammation. Their combined effects are not additive. A model for mitochondrial reactive oxygen species (ROS) quenching via targeted overexpression of the human catalase gene to the mitochondria (MCAT mice), are protected from isolation- and/or simulated microgravity-induced changes in cytokine expression. These findings suggest a key role for mitochondrial ROS signaling in neuroinflammatory responses to spaceflight and prolonged bedrest, isolation, and confinement on Earth.

Cross-sectional survey. To evaluate the annual influenza vaccination coverage rate (IVCR) among community-dwelling individuals with spinal cord injury (SCI). SCI community in Switzerland. Participants were responders to the influenza vaccination question (n = 492) in the 2012 community survey of the Swiss Spinal Cord Injury (SwiSCI) cohort study. IVCR of SwiSCI participants were compared to the normative Swiss population, sampled in the Swiss Health Survey of 2012 using direct standardization, logistic regression standardization, and a genetic matching approach to control for differences in age, sex, and quarterly period of survey response. Individuals with SCI showed higher crude (26%, 95% confidence interval (CI): 22–30%) and age- and sex-standardized (24%, CI: 23–24%) IVCR than observed in the general population (15% CI, 14–15%). The adjustment for age and sex as well as quarterly period of survey response showed that the standardized IVCR of individuals with SCI (17%; CI: 12–23%) approached that of the general population. Low IVCR of about 10% were found among individuals with SCI younger than 45 years. IVCR were similar between men and women and between individuals with incomplete and complete paraplegia and tetraplegia. The IVCR in individuals with chronic SCI was not higher than in the general population and much lower than guidelines recommend. The improvement of the IVCR is an important target of health policy in SCI in Switzerland as to reduce the evidenced excess burden in respiratory-disease related morbidity and mortality.

Dictyoglomus turgidum is a hyperthermophilic, anaerobic, gram-negative bacterium that shows an array of putative glycoside hydrolases (GHs) encoded by its genome, a feature that makes this microorganism very interesting for biotechnological applications. The aim of this work is the characterization of a hyperthermophilic GH5, Dtur_0671, of D. turgidum, annotated as endoglucanase and herein named DturCelB in agreement to DturCelA, which was previously characterized. The synthetic gene was expressed in Escherichia coli. The purified recombinant enzyme is active as a monomer (40 kDa) and CD structural studies showed a conserved α/β structure at different temperatures (25 and 70 °C) and high thermoresistance (Tm of 88 °C). Interestingly, the enzyme showed high endo-β-1,4-mannanase activity vs various mannans, but low endo-β-1,4 glucanase activity towards carboxymethylcellulose. The K M and V max of DturCelB were determined for both glucomannan and CMC: they were 4.70 mg/ml and 473.1 μmol/min mg and 1.83 mg/ml and 1.349 μmol/min mg, respectively. Its optimal activity towards temperature and pH resulted to be 70 °C and pH 5.4, respectively. Further characterization highlighted good thermal stability (~ 50% of enzymatic activity after 2 h at 70 °C) and pH stability over a broad range (> 90% of activity after 1 h in buffer, ranging pH 5–9); resistance to chemicals was also observed.

Descriptive qualitative and quantitative study using cross-sectional data from the Swiss Spinal Cord Injury Cohort Study (SwiSCI).To determine the key demands and characteristics of occupations performed by individuals with spinal cord injury (SCI).Swiss community.Job titles indicated by SwiSCI participants were linked to occupational titles from the Occupational Information Network (O*NET) and then frequency-analyzed across sociodemographic and injury-related factors. Subsequently, average O*NET relevance values ranging from 0 to 100 were calculated for the occupations' demands and characteristics, both in general and stratified by injury-related factors.The 1549 study participants indicated a total of 717 job titles and were primarily employed in administrative and management occupations (22.1% and 16.4%, respectively). The participants' occupations predominantly required verbal abilities (average relevance [AR]=68.4) and complex problem solving skills (AR=55.8) and were characterized by conventional work tasks (AR=62.9) and social relationships (AR=58.6). Both the occupations' frequency distribution as well as the average relevance levels of their demands and characteristics differed by SCI severity.Individuals with SCI perform a broad range of occupations that are mainly characterized by cognitive and communicative demands, while physical demands are of minor importance. By informing the development of job matching profiles for vocational guidance, our study facilitates the determination of well-matching jobs for persons with SCI and may contribute to a more sustainable return to work of the affected persons.