Kinetics of bond formation in crosslinked gelatin gels

In chemical crosslinking of gelatin solutions, two different time scales affect the kinetics of the gel formation in the experiments. We complement the experimental study with Monte Carlo numerical simulations of a lattice model. This approach shows that the two characteristic time scales are related to the formation of single bonds crosslinker-chain and of bridges between chains. In particular their ratio turns out to control the kinetics of the gel formation. We discuss the effect of the concentration of chains. Finally our results suggest that, by varying the probability of forming bridges as an independent parameter, one can finely tune the kinetics of the gelation via the ratio of the two characteristic times.Comment: 8 pages, 9 figures, revised versio

Associations of Vitamin D with Inter- and Intra-Muscular Adipose Tissue and Insulin Resistance in Women with and without Polycystic Ovary Syndrome

Low vitamin D and insulin resistance are common in polycystic ovary syndrome (PCOS) and associated with higher inter- and intra-muscular adipose tissue (IMAT). We investigated associations between vitamin D, IMAT and insulin resistance in a cross-sectional study of 40 women with PCOS and 30 women without PCOS, and pre- and post-exercise in a 12-week intervention in 16 overweight participants (10 with PCOS and six without PCOS). A non-classical body mass index (BMI) threshold was used to differentiate lean and overweight women (BMI ≥ 27 kg/m²). Measurements included plasma 25-hydroxyvitamin D (25OHD), insulin resistance (glucose infusion rate (GIR; mg/m²/min), fasting glucose and insulin, and glycated haemoglobin), visceral fat, mid-thigh IMAT (computed tomography) and total body fat (dual-energy X-ray absorptiometry). Women with both PCOS and low 25OHD levels had the lowest GIR (all p < 0.05). Higher IMAT was associated with lower 25OHD (B = -3.95; 95% CI -6.86, -1.05) and GIR (B = -21.3; 95% CI -37.16, -5.44) in women with PCOS. Overweight women with pre-exercise 25OHD ≥30 nmol/L had significant increases in GIR, and decreases in total and visceral fat (all p < 0.044), but no associations were observed when stratified by PCOS status. Women with PCOS and low 25OHD levels have increased insulin resistance which may be partly explained by higher IMAT. Higher pre-training 25OHD levels may enhance exercise-induced changes in body composition and insulin resistance in overweight women

Enhanced skeletal muscle ribosome biogenesis, yet attenuated mTORC1 and ribosome biogenesis-related signalling, following short-term concurrent versus single-mode resistance training

Combining endurance training with resistance training (RT) may attenuate skeletal muscle hypertrophic adaptation versus RT alone; however, the underlying mechanisms are unclear. We investigated changes in markers of ribosome biogenesis, a process linked with skeletal muscle hypertrophy, following concurrent training versus RT alone. Twenty-three males underwent eight weeks of RT, either performed alone (RT group, n = 8), or combined with either high-intensity interval training (HIT+RT group, n = 8), or moderate-intensity continuous training (MICT+RT group, n = 7). Muscle samples (vastus lateralis) were obtained before training, and immediately before, 1 h and 3 h after the final training session. Training-induced changes in basal expression of the 45S ribosomal RNA (rRNA) precursor (45S pre-rRNA), and 5.8S and 28S mature rRNAs, were greater with concurrent training versus RT. However, during the final training session, RT further increased both mTORC1 (p70S6K1 and rps6 phosphorylation) and 45S pre-rRNA transcription-related signalling (TIF-1A and UBF phosphorylation) versus concurrent training. These data suggest that when performed in a training-accustomed state, RT induces further increases mTORC1 and ribosome biogenesis-related signalling in human skeletal muscle versus concurrent training; however, changes in ribosome biogenesis markers were more favourable following a period of short-term concurrent training versus RT performed alon

Polycystic ovary syndrome

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included.Polycystic ovary syndrome (PCOS) affects 5-20% of women of reproductive age worldwide. The condition is characterized by hyperandrogenism, ovulatory dysfunction and polycystic ovarian morphology (PCOM) - with excessive androgen production by the ovaries being a key feature of PCOS. Metabolic dysfunction characterized by insulin resistance and compensatory hyperinsulinaemia is evident in the vast majority of affected individuals. PCOS increases the risk for type 2 diabetes mellitus, gestational diabetes and other pregnancy-related complications, venous thromboembolism, cerebrovascular and cardiovascular events and endometrial cancer. PCOS is a diagnosis of exclusion, based primarily on the presence of hyperandrogenism, ovulatory dysfunction and PCOM. Treatment should be tailored to the complaints and needs of the patient and involves targeting metabolic abnormalities through lifestyle changes, medication and potentially surgery for the prevention and management of excess weight, androgen suppression and/or blockade, endometrial protection, reproductive therapy and the detection and treatment of psychological features. This Primer summarizes the current state of knowledge regarding the epidemiology, mechanisms and pathophysiology, diagnosis, screening and prevention, management and future investigational directions of the disorder.Robert J Norman, Ruijin Wu and Marcin T Stankiewic

Definitions of basic terms relating to polymer liquid crystals (IUPAC Recommendations 2001)

The document first gives definitions of basic terms related to liquid-crystalline and mesomorphic states of matter and then terms specific to the classification of liquid-crystal polymers. The terms have been restricted to those most commonly encountered in the structural description of the latter class of materials. The terms have been selected from the recently published comprehensive document "Definitions of basic terms relating to low-molar-mass and polymer liquid crystals" [Pure and Applied Chemistry 73 (5), 845-895 (2001)] and are intended to form a readily usable guide for the reader interested in the structural description of polymer liquid crystals. The more comprehensive document should be used for terminology associated with types of mesophases and the optical and physical characteristics of liquid-crystalline materials. The advice given by representatives of the International Liquid Crystal Society for the preparation of this document is gratefully acknowledged.Fil:Barón, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

The effectiveness of high intensity intermittent training on metabolic, reproductive and mental health in women with polycystic ovary syndrome: study protocol for the iHIT- randomised controlled trial

Abstract Background Polycystic ovary syndrome (PCOS) is a reproductive-metabolic condition. Insulin resistance is a hallmark of PCOS and is related to increased hyperandrogenism that drives inherent metabolic, reproductive and psychological features of the syndrome. Insulin resistance in women with PCOS is managed by weight loss, lifestyle interventions (i.e. exercise, diet) and insulin-sensitising medications. This manuscript describes the protocol of our study evaluating the effectiveness of high intensity intermittent training (HIIT) or moderate intensity exercise on cardiometabolic, reproductive and mental health in overweight women with PCOS. Methods/design We will employ a three arm, parallel-group, randomised controlled trial recruiting 60 women diagnosed with PCOS, aged between 18 and 45 years and with a body mass index (BMI) greater than 25 kg/m2. Following screening and baseline testing, women will be randomised by simple randomisation procedure using computer generated sequence allocation to undergo one of two 12-week supervised interventions: either HIIT or moderate intensity exercise (standard supervised exercise), or to standard care [Con] (unsupervised lifestyle advice) at a 1:1:1 allocation ratio. The primary outcome for this trial is to measure the improvements in metabolic health; specifically changes in insulin sensitivity in response to different exercise intensities. Baseline and post-intervention testing include anthropometric measurements, cardiorespiratory fitness testing, reproductive hormone profiles (anti-müllerian hormone and steroid profiles), metabolic health, health-related quality of life and mental health questionnaires and objective and subjective lifestyle monitoring. Reporting of the study will follow the CONSORT statement. Discussion This trial aims to demonstrate the comparative efficacy and maintenance of different exercise intensities to advance the understanding of PCOS management and provide insight into the optimal exercise intensity for improved cardiometabolic outcomes. Secondary outcomes will include the impact of different exercise protocols on reproductive hormone profiles, mental health and health-related quality of life. Trial registration Australian New Zealand Clinical Trials Registry, ACTRN12615000242527. Registered on 17 March 2015

Source-based nomenclature for single-strand homopolymers and copolymers (IUPAC Recommendations 2016)

IUPAC recommendations on source-based nomenclature for single-strand polymers have so far addressed its application mainly to copolymers, non-linear polymers and polymer assemblies, and within generic source-based nomenclature of polymers. In this document, rules are formulated for devising a satisfactory source-based name for a polymer, whether homopolymer or copolymer, which are as clear and rigorous as possible. Thus, the source-based system for naming polymers is presented in a totality that serves as a user-friendly alternative to the structure-based system of polymer nomenclature. In addition, because of their widespread and established use, recommendations for the use of traditional names of polymers are also elaborated

Recommendations from the international evidence-based guideline for the assessment and management of polycystic ovary syndrome

Study QuestionWhat is the recommended assessment and management of women with polycystic ovary syndrome (PCOS), based on the best available evidence, clinical expertise, and consumer preference? Summary AnswerInternational evidence-based guidelines including 166 recommendations and practice points, addressed prioritized questions to promote consistent, evidence-based care and improve the experience and health outcomes of women with PCOS. What is Known AlreadyPrevious guidelines either lacked rigorous evidence-based processes, did not engage consumer and international multidisciplinary perspectives, or were outdated. Diagnosis of PCOS remains controversial and assessment and management are inconsistent. The needs of women with PCOS are not being adequately met and evidence practice gaps persist. Study Design, Size, DurationInternational evidence-based guideline development engaged professional societies and consumer organizations with multidisciplinary experts and women with PCOS directly involved at all stages. Appraisal of Guidelines for Research and Evaluation (AGREE) II-compliant processes were followed, with extensive evidence synthesis. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework was applied across evidence quality, feasibility, acceptability, cost, implementation and ultimately recommendation strength. Participants/Materials, Setting, MethodsGovernance included a six continent international advisory and a project board, five guideline development groups (GDGs), and consumer and translation committees. Extensive health professional and consumer engagement informed guideline scope and priorities. Engaged international society-nominated panels included pediatrics, endocrinology, gynecology, primary care, reproductive endocrinology, obstetrics, psychiatry, psychology, dietetics, exercise physiology, public health and other experts, alongside consumers, project management, evidence synthesis, and translation experts. Thirty-seven societies and organizations covering 71 countries engaged in the process. Twenty face-to-face meetings over 15months addressed 60 prioritized clinical questions involving 40 systematic and 20 narrative reviews. Evidence-based recommendations were developed and approved via consensus voting within the five guideline panels, modified based on international feedback and peer review, with final recommendations approved across all panels. Main Results and the Role of ChanceThe evidence in the assessment and management of PCOS is generally of low to moderate quality. The guideline provides 31 evidence based recommendations, 59 clinical consensus recommendations and 76 clinical practice points all related to assessment and management of PCOS. Key changes in this guideline include: (a) considerable refinement of individual diagnostic criteria with a focus on improving accuracy of diagnosis; (b) reducing unnecessary testing; (c) increasing focus on education, lifestyle modification, emotional wellbeing and quality of life; and (d) emphasizing evidence based medical therapy and cheaper and safer fertility management. Limitations, Reasons for CautionOverall evidence is generally low to moderate quality, requiring significantly greater research in this neglected, yet common condition, especially around refining specific diagnostic features in PCOS. Regional health system variation is acknowledged and a process for guideline and translation resource adaptation is provided. Wider Implications of the FindingsThe international guideline for the assessment and management of PCOS provides clinicians with clear advice on best practice based on the best available evidence, expert multidisciplinary input and consumer preferences. Research recommendations have been generated and a comprehensive multifaceted dissemination and translation program supports the guideline with an integrated evaluation program.Peer reviewe