Maturation-related changes in the development and etiology of neuromuscular fatigue

International audiencePurpose: The aim of the present study was to investigate the role of maturation on the etiology of neuromuscular fatigue induced by repeated maximal voluntary isometric contractions (MVIC).Methods: Nine prepubertal boys (9.9 ± 1.3 years), eight male adolescents (13.6 ± 1.3 years) and eleven men (23.4 ± 3.0 years) performed a series of repeated isometric MVICs of the knee extensors until the MVIC torque reached 60% of its initial value. Magnetic stimulations were delivered to the femoral nerve every five MVICs to follow the course of voluntary activation level (VA) and the potentiated twitch torque (Qtwpot).Results: Task failure was reached after 52.9 ± 12.7, 42.6 ± 12.5, and 26.6 ± 6.3 repetitions in boys, adolescents and men, respectively. VA remained unchanged in men whereas it decreased significantly and similarly in boys and adolescents (p < 0.001). In contrast, Qtwpot remained unchanged in boys and decreased significantly less in adolescents than adults (p < 0.05).Conclusions: Children and adolescents experience less peripheral and more central fatigue than adults. However, adolescents experience more peripheral fatigue than children for a comparable amount of central fatigue. This finding supports the idea that the tolerance of the central nervous system to peripheral fatigue could increase during maturation

Second primary cancer risk - the impact of applying different definitions of multiple primaries: results from a retrospective population-based cancer registry study

Background: There is evidence that cancer survivors are at increased risk of second primary cancers. Changes in the prevalence of risk factors and diagnostic techniques may have affected more recent risks.&lt;p&gt;&lt;/p&gt; Methods: We examined the incidence of second primary cancer among adults in the West of Scotland, UK, diagnosed with cancer between 2000 and 2004 (n = 57,393). We used National Cancer Institute Surveillance Epidemiology and End Results and International Agency for Research on Cancer definitions of multiple primary cancers and estimated indirectly standardised incidence ratios (SIR) with 95% confidence intervals (CI).&lt;p&gt;&lt;/p&gt; Results: There was a high incidence of cancer during the first 60 days following diagnosis (SIR = 2.36, 95% CI = 2.12 to 2.63). When this period was excluded the risk was not raised, but it was high for some patient groups; in particular women aged &#60;50 years with breast cancer (SIR = 2.13, 95% CI = 1.58 to 2.78), patients with bladder (SIR = 1.41, 95% CI = 1.19 to 1.67) and head &#38; neck (SIR = 1.93, 95% CI = 1.67 to 2.21) cancer. Head &#38; neck cancer patients had increased risks of lung cancer (SIR = 3.75, 95% CI = 3.01 to 4.62), oesophageal (SIR = 4.62, 95% CI = 2.73 to 7.29) and other head &#38; neck tumours (SIR = 6.10, 95% CI = 4.17 to 8.61). Patients with bladder cancer had raised risks of lung (SIR = 2.18, 95% CI = 1.62 to 2.88) and prostate (SIR = 2.41, 95% CI = 1.72 to 3.30) cancer.&lt;p&gt;&lt;/p&gt; Conclusions: Relative risks of second primary cancers may be smaller than previously reported. Premenopausal women with breast cancer and patients with malignant melanomas, bladder and head &#38; neck cancers may benefit from increased surveillance and advice to avoid known risk factors

A panel of kallikrein markers can predict outcome of prostate biopsy following clinical work-up: an independent validation study from the European Randomized Study of Prostate Cancer screening, France

<p>Abstract</p> <p>Background</p> <p>We have previously shown that a panel of kallikrein markers - total prostate-specific antigen (PSA), free PSA, intact PSA and human kallikrein-related peptidase 2 (hK2) - can predict the outcome of prostate biopsy in men with elevated PSA. Here we investigate the properties of our panel in men subject to clinical work-up before biopsy.</p> <p>Methods</p> <p>We applied a previously published predictive model based on the kallikrein panel to 262 men undergoing prostate biopsy following an elevated PSA (≥ 3 ng/ml) and further clinical work-up during the European Randomized Study of Prostate Cancer screening, France. The predictive accuracy of the model was compared to a "base" model of PSA, age and digital rectal exam (DRE).</p> <p>Results</p> <p>83 (32%) men had prostate cancer on biopsy of whom 45 (54%) had high grade disease (Gleason score 7 or higher). Our model had significantly higher accuracy than the base model in predicting cancer (area-under-the-curve [AUC] improved from 0.63 to 0.78) or high-grade cancer (AUC increased from 0.77 to 0.87). Using a decision rule to biopsy those with a 20% or higher risk of cancer from the model would reduce the number of biopsies by nearly half. For every 1000 men with elevated PSA and clinical indication for biopsy, the model would recommend against biopsy in 61 men with cancer, the majority (≈80%) of whom would have low stage <it>and </it>low grade disease at diagnosis.</p> <p>Conclusions</p> <p>In this independent validation study, the model was highly predictive of prostate cancer in men for whom the decision to biopsy is based on both elevated PSA and clinical work-up. Use of this model would reduce a large number of biopsies while missing few cancers.</p

CRISPR-assisted detection of RNA-protein interactions in living cells.

We have developed CRISPR-assisted RNA-protein interaction detection method (CARPID), which leverages CRISPR-CasRx-based RNA targeting and proximity labeling to identify binding proteins of specific long non-coding RNAs (lncRNAs) in the native cellular context. We applied CARPID to the nuclear lncRNA XIST, and it captured a list of known interacting proteins and multiple previously uncharacterized binding proteins. We generalized CARPID to explore binders of the lncRNAs DANCR and MALAT1, revealing the method's wide applicability in identifying RNA-binding proteins

Towards a climate-neutral energy system in the Netherlands

This paper presents two different scenarios for the energy system of the Netherlands that achieve the Dutch government's national target of near net-zero greenhouse gas emissions in 2050. Using the system optimisation model OPERA, the authors have analysed the technology, sector and cost implications of the assumptions underlying these scenarios. While the roles of a number of key energy technology and emission mitigation options are strongly dependent on the scenario and cost assumptions, the analysis yields several common elements that appear in both scenarios and that consistently appear under differing cost assumptions. For example, one of the main options for the decarbonisation of the Dutch energy system is electrification of energy use in end-use sectors and for the production of renewable hydrogen with electrolysers. As a result the level of electricity generation in 2050 will be three to four times higher than present generation levels. Ultimately, renewable energy – particularly from wind turbines and solar panels – is projected to account for the vast majority of electricity generation, around 99% in 2050. Imbalances between supply and demand resulting from this variable renewable electricity production can be managed via flexibility options, including demand response and energy storage. Hydrogen also becomes an important energy carrier, notably for transportation and in industry. If import prices are lower than costs of domestic production from natural gas with CCS or through electrolysis from renewable electricity (2.4–2.7 €/kgH2), the use of hydrogen increases, especially in the built environment

Validation of immature ovine bone models using digital image correlation

Data on paediatric bone properties is very limited due to the scarcity of specimen in this particular age range, and due to ethical complexities regarding experimental testing on paediatric cadavers. A recently validated technique for adults using CT-based finite element analysis (FEA), has the potential to provide a deeper understanding of immature bone fracture mechanism without the need of extensive paediatric cadaveric testing. This thesis aimed to investigate the validity of a CT-based FEA approach for immature bones, using lamb bones as surrogate to children’s bones, by comparing strain results against 3D digital image correlation (3D-DIC) data during four-point bending tests. In this thesis, two experimental set-ups were designed to run four-point bending tests on lamb femur specimens using 3D-DIC to capture full-field surface strain. The first set of experiments applied bending load directly onto the femurs, whereas the second set of experiments embedded the bones with the load applied to the embedding materials instead. The four-point bending tests were replicated using an image-based FEA approach. The FE geometries were segmented from either QCT or µCT images. The material properties were derived from the CT image’s attenuations using existing empirical findings relating elastic modulus to bone mineral density. Various model set-ups and boundary conditions have been investigated in order to determine the best ones that matched the experimental results. Through assessing and comparing results obtained in the experimental tests and the FEA, the improved FE approach was successfully validated using lamb bones. Furthermore, it was concluded that the cortical region of the diaphysis (mineralised bone) of infants and toddlers can be modelled with adequate accuracy using just a homogeneous mesh of isotropic elastic modulus. For children of three years and above, anisotropy of the bone may need to be considered to appropriately replicate the properties of lamellar bone. Further studies are required in order to better characterize the empirical relationship between elastic modulus and mineral density in immature bone, as well as the cortical and trabecular bone material properties at various developmental ages. The periosteum plays an important role in the fracture behavior of immature bone; thus, it is important to separately characterize the material properties of the periosteum. For a complete representation of bone in vivo, both the periosteum and the mineralizing bone should be integrated into the FE model

Quelques éléments de la défense côtière en Pologne

Jegu Olivier. Quelques éléments de la défense côtière en Pologne. In: Méditerranée, tome 93, 4-1999. Dynamiques naturelles et gestion des espaces littoraux, sous la direction de Serge Suanez, Mireille Provansal et Carole Bruzzi. p. 80