405 research outputs found

    Physiological and Biomechanical Responses of Highly Trained Distance Runners to Lower-Body Positive Pressure Treadmill Running

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    Background: As a way to train at faster running speeds, add training volume, prevent injury, or rehabilitate after an injury, lower-body positive pressure treadmills (LBPPT) have become increasingly commonplace among athletes. However, there are conflicting evidence and a paucity of data describing the physiological and biomechanical responses to LBPPT running in highly trained or elite caliber runners at the running speeds they habitually train at, which are considerably faster than those of recreational runners. Furthermore, data is lacking regarding female runners’ responses to LBPPT running. Therefore, this study was designed to evaluate the physiological and biomechanical responses to LBPPT running in highly trained male and female distance runners. Methods: Fifteen highly trained distance runners (seven male; eight female) completed a single running test composed of 4 × 9-min interval series at fixed percentages of body weight ranging from 0 to 30% body weight support (BWS) in 10% increments on LBPPT. The first interval was always conducted at 0% BWS; thereafter, intervals at 10, 20, and 30% BWS were conducted in random order. Each interval consisted of three stages of 3 min each, at velocities of 14.5, 16.1, and 17.7 km·h−1 for men and 12.9, 14.5, and 16.1 km·h−1 for women. Expired gases, ventilation, breathing frequency, heart rate (HR), rating of perceived exertion (RPE), and stride characteristics were measured during each running speed and BWS. Results: Male and female runners had similar physiological and biomechanical responses to running on LBPPT. Increasing BWS increased stride length (p \u3c 0.02) and flight duration (p \u3c 0.01) and decreased stride rate (p \u3c 0.01) and contact time (p \u3c 0.01) in small-large magnitudes. There was a large attenuation of oxygen consumption (VO2) relative to BWS (p \u3c 0.001), while there were trivial-moderate reductions in respiratory exchange ratio, minute ventilation, and respiratory frequency (p \u3e 0.05), and small-large effects on HR and RPE (p \u3c 0.01). There were trivial-small differences in VE, respiratory frequency, HR, and RPE for a given VO2 across various BWS (p \u3e 0.05). Conclusions: The results indicate the male and female distance runners have similar physiological and biomechanical responses to LBPPT running. Overall, the biomechanical changes during LBPPT running all contributed to less metabolic cost and corresponding physiological changes. Keywords: AlterG, Lower-body positive pressure, Body weight support, Anti-gravity, Running, Stride characteristics, Physiological characteristics, Metabolic demand, Oxygen demand, Oxygen cos

    'Keeping busy' as agency in early desistance

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    Agency in desistance research has often been understood as deliberate action undertaken in pursuit of a desisting identity. Through a micro-longitudinal approach, this research focuses on the early desistance experiences of a number of mainly white British female participants. Agency was exhibited not with a new identity in mind, but instead through 'keeping busy'. The surprising lack of identity concerns may be due to the early stages of the participants' desistance experiences, with new identities emerging later in the process. Alternatively, it may indicate a fundamental difference to the classic desistance narrative, linked to the differences between this sample and the frequently researched, Western, male, high-frequency offender. Finally, important aspects of the cultures surrounding desistance research may have shaped the narratives of desisters and the biases of researchers towards finding a concern for identity when this is not necessarily experienced in the everyday lives of desisters

    Starting to Stop: Young Offenders' Desistance from Crime

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    This paper explores the complexities of the interplay between structural and agentic changes in 21 young offenders' lives as they start to stop offending. The young people's ability to desist from crime was dependent upon their engagement with a 'hook for change', their development of prosocial relationships and 'knifing off' of elements of their offending past, the extent of their identity change, and their confidence about desistance. Desistance was less likely in the absence of a 'hook' and where offenders were running a 'condemnation script'. The study challenges previous research that argues that desistance from crime in adolescence is unlikely

    Identification and Characterization of Inhibitors of Human Apurinic/apyrimidinic Endonuclease APE1

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    APE1 is the major nuclease for excising abasic (AP) sites and particular 3′-obstructive termini from DNA, and is an integral participant in the base excision repair (BER) pathway. BER capacity plays a prominent role in dictating responsiveness to agents that generate oxidative or alkylation DNA damage, as well as certain chain-terminating nucleoside analogs and 5-fluorouracil. We describe within the development of a robust, 1536-well automated screening assay that employs a deoxyoligonucleotide substrate operating in the red-shifted fluorescence spectral region to identify APE1 endonuclease inhibitors. This AP site incision assay was used in a titration-based high-throughput screen of the Library of Pharmacologically Active Compounds (LOPAC1280), a collection of well-characterized, drug-like molecules representing all major target classes. Prioritized hits were authenticated and characterized via two high-throughput screening assays – a Thiazole Orange fluorophore-DNA displacement test and an E. coli endonuclease IV counterscreen – and a conventional, gel-based radiotracer incision assay. The top, validated compounds, i.e. 6-hydroxy-DL-DOPA, Reactive Blue 2 and myricetin, were shown to inhibit AP site cleavage activity of whole cell protein extracts from HEK 293T and HeLa cell lines, and to enhance the cytotoxic and genotoxic potency of the alkylating agent methylmethane sulfonate. The studies herein report on the identification of novel, small molecule APE1-targeted bioactive inhibitor probes, which represent initial chemotypes towards the development of potential pharmaceuticals

    Expression of BMI-1 and Mel-18 in breast tissue - a diagnostic marker in patients with breast cancer

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    <p>Abstract</p> <p>Background</p> <p>Polycomb Group (PcG) proteins are epigenetic silencers involved in maintaining cellular identity, and their deregulation can result in cancer. Expression of Mel-18 and Bmi-1 has been studied in tumor tissue, but not in adjacent non-cancerous breast epithelium. Our study compares the expression of the two genes in normal breast epithelium of cancer patients and relates it to the level of expression in the corresponding tumors as well as in breast epithelium of healthy women.</p> <p>Methods</p> <p>A total of 79 tumors, of which 71 malignant tumors of the breast, 6 fibroadenomas, and 2 DCIS were studied and compared to the reduction mammoplastic specimens of 11 healthy women. In addition there was available adjacent cancer free tissue for 23 of the malignant tumors. The tissue samples were stored in RNAlater, RNA was isolated to create expression microarray profile. These two genes were then studied more closely first on mRNA transcription level by microarrays (Agilent 44 K) and quantitative RT-PCR (TaqMan) and then on protein expression level using immunohistochemistry.</p> <p>Results</p> <p>Bmi-1 mRNA is significantly up-regulated in adjacent normal breast tissue in breast cancer patients compared to normal breast tissue from noncancerous patients. Conversely, mRNA transcription level of Mel-18 is lower in normal breast from patients operated for breast cancer compared to breast tissue from mammoplasty. When protein expression of these two genes was evaluated, we observed that most of the epithelial cells were positive for Bmi-1 in both groups of tissue samples, although the expression intensity was stronger in normal tissue from cancer patients compared to mammoplasty tissue samples. Protein expression of Mel-18 showed inversely stronger intensity in tissue samples from mammoplasty compared to normal breast tissue from patients operated for breast cancer.</p> <p>Conclusion</p> <p>Bmi-1 mRNA level is consistently increased and Mel-18 mRNA level is consistently decreased in adjacent normal breast tissue of cancer patients as compared to normal breast tissue in women having had reduction mammoplasties. Bmi-1/Mel-18 ratio can be potentially used as a tool for stratifying women at risk of developing malignancy.</p

    Prioritizing micronutrients for the purpose of reviewing their requirements: a protocol developed by EURRECA

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    Background: The EURRECA (EURopean micronutrient RECommendations Aligned) Network of Excellence (http://www.eurreca.org) is working towards the development of aligned recommendations. A protocol was required to assign resources to those micronutrients for which recommendations are most in need of alignment. Methods: Three important 'a priori' criteria were the basis for ranking micronutrients: (A) the amount of new scientific evidence, particularly from randomized controlled trials; (B) the public health relevance of micronutrients; (C) variations in current micronutrient recommendations. A total of 28 micronutrients were included in the protocol, which was initially undertaken centrally by one person for each of the different population groups defined in EURRECA: infants, children and adolescents, adults, elderly, pregnant and lactating women, and low income and immigrant populations. The results were then reviewed and refined by EURRECA's population group experts. The rankings of the different population groups were combined to give an overall average ranking of micronutrients. Results: The 10 highest ranked micronutrients were vitamin D, iron, folate, vitamin B12, zinc, calcium, vitamin C, selenium, iodine and copper. Conclusions: Micronutrient recommendations should be regularly updated to reflect new scientific nutrition and public health evidence. The strategy of priority setting described in this paper will be a helpful procedure for policy makers and scientific advisory bodies. European Journal of Clinical Nutrition (2010) 64, S19-530; doi:10.1038/ejcn.2010.5
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