Le rôle de la région locomotrice mésencéphalique (RLM) dans l’initiation du pas, la marche et le contrôle postural chez l’homme reste mal connu. Chez les patients avec maladie de Parkinson, une perte ...des neurones cholinergiques dans cette région a été corrélée à la survenue du freezing de la marche et/ou des chutes.
Dans ce travail de recherche, l’objectif était d’étudier les modulations de l’activité neuronale de la RLM lors de l’initiation du pas chez ces patients.
Quatre patients parkinsoniens (âge : 67±2 ans ; durée d’évolution : 11±6 ans) ont été opérés pour implantation d’électrodes dans la RLM dans le cadre d’un programme de recherche thérapeutique (Inserm, RBM C15-46). L’activité neuronale de la RLM en champ de potentiels locaux a été enregistrée en demandant au patient d’initier la marche sur une plateforme de force.
Lors de l’initiation du pas, il existait une augmentation de l’activité dans les bandes de fréquence basses (4–12Hz) qui débutait au moment du trigger pour se poursuivre pendant toute la durée du pas. Lors de la phase des ajustements posturaux anticipatoires on retrouvait une diminution de l’activité bêta bas (12–20Hz), disparaissant après la prise du traitement dopaminergique, avec une augmentation de l’activité bêta haut (20–35Hz) non modifiée par le traitement.
Ces données confirment le rôle de la RLM dans l’initiation du pas chez l’homme, sous la dépendance en partie du tonus dopaminergique des ganglions de la base.
Population growth, increasing energy demand and the depletion of fossil fuel reserves necessitate a search for sustainable alternatives for electricity generation. Hydropower could replace a large ...part of the contribution of gas and oil to the present energy mix. However, previous high-resolution estimates of hydropower potential have been local, and have yet to be applied on a global scale. This study is the first to formally present a detailed evaluation of the hydropower potential of each location, based on slope and discharge of each river in the world. The gross theoretical hydropower potential is approximately 52 PWh/year divided over 11.8 million locations. This 52 PWh/year is equal to 33% of the annually required energy, while the present energy production by hydropower plants is just 3% of the annually required energy. The results of this study: all potentially interesting locations for hydroelectric power plants, are available online.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance ...Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an "ensemble averaging" procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferred at fast growth). In addition, CAFBA allows for quantitatively accurate predictions on the rate of acetate excretion and growth yield based on only 3 parameters determined by empirical growth laws.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The scarcity of nitrogen in Earth's crust, combined with challenging synthesis, have made inorganic nitrides a relatively unexplored class of compounds compared to their naturally abundant oxide ...counterparts. To facilitate exploration of their compositional space
via a priori
modeling, and to help
a posteriori
structure verification not limited to inferring the oxidation state of redox-active cations, we derive a suite of bond-valence parameters and Lewis acid strength values for 76 cations observed bonding to N
3−
, and further outline a baseline statistical knowledge of bond lengths for these compounds. Examination of structural and electronic effects responsible for the functional properties and anomalous bonding behavior of inorganic nitrides shows that many mechanisms of bond-length variation ubiquitous to oxide and oxysalt compounds (
e.g.
, lone-pair stereoactivity, the Jahn-Teller and pseudo Jahn-Teller effects) are similarly pervasive in inorganic nitrides, and are occasionally observed to result in greater distortion magnitude than their oxide counterparts. We identify promising functional units for exploring uncharted chemical spaces of inorganic nitrides,
e.g.
multiple-bond metal centers with promise regarding the development of a post-Haber-Bosch process proceeding at milder reaction conditions, and promote an atomistic understanding of chemical bonding in nitrides relevant to such pursuits as the development of a model of ion substitution in solids, a problem of great relevance to semiconductor doping whose solution would fast-track the development of compound solar cells, battery materials, electronics, and more.
Navigating high-return chemical spaces in inorganic nitrides
via
identification of coordination units bearing functional properties.
In most species, crossovers (COs) are essential for the accurate segregation of homologous chromosomes at the first meiotic division. Their number and location are tightly regulated. Here, we report ...a detailed, genome-wide characterization of the rate and localization of COs in Arabidopsis thaliana, in male and female meiosis. We observed dramatic differences between male and female meiosis which included: (i) genetic map length; 575 cM versus 332 cM respectively; (ii) CO distribution patterns: male CO rates were very high at both ends of each chromosome, whereas female CO rates were very low; (iii) correlations between CO rates and various chromosome features: female CO rates correlated strongly and negatively with GC content and gene density but positively with transposable elements (TEs) density, whereas male CO rates correlated positively with the CpG ratio. However, except for CpG, the correlations could be explained by the unequal repartition of these sequences along the Arabidopsis chromosome. For both male and female meiosis, the number of COs per chromosome correlates with chromosome size expressed either in base pairs or as synaptonemal complex length. Finally, we show that interference modulates the CO distribution both in male and female meiosis.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Soil compaction represents a major challenge for modern agriculture. Compaction is intuitively thought to reduce root growth by limiting the ability of roots to penetrate harder soils. We report that ...root growth in compacted soil is instead actively suppressed by the volatile hormone ethylene. We found that mutant
and rice roots that were insensitive to ethylene penetrated compacted soil more effectively than did wild-type roots. Our results indicate that soil compaction lowers gas diffusion through a reduction in air-filled pores, thereby causing ethylene to accumulate in root tissues and trigger hormone responses that restrict growth. We propose that ethylene acts as an early warning signal for roots to avoid compacted soils, which would be relevant to research into the breeding of crops resilient to soil compaction.
Summary Background Initial results of the ChemoRadiotherapy for Oesophageal cancer followed by Surgery Study (CROSS) comparing neoadjuvant chemoradiotherapy plus surgery versus surgery alone in ...patients with squamous cell carcinoma and adenocarcinoma of the oesophagus or oesophagogastric junction showed a significant increase in 5-year overall survival in favour of the neoadjuvant chemoradiotherapy plus surgery group after a median of 45 months' follow-up. In this Article, we report the long-term results after a minimum follow-up of 5 years. Methods Patients with clinically resectable, locally advanced cancer of the oesophagus or oesophagogastric junction (clinical stage T1N1M0 or T2–3N0–1M0, according to the TNM cancer staging system, sixth edition) were randomly assigned in a 1:1 ratio with permuted blocks of four or six to receive either weekly administration of five cycles of neoadjuvant chemoradiotherapy (intravenous carboplatin AUC 2 mg/mL per min and intravenous paclitaxel 50 mg/m2 of body-surface area for 23 days) with concurrent radiotherapy (41·4 Gy, given in 23 fractions of 1·8 Gy on 5 days per week) followed by surgery, or surgery alone. The primary endpoint was overall survival, analysed by intention-to-treat. No adverse event data were collected beyond those noted in the initial report of the trial. This trial is registered with the Netherlands Trial Register, number NTR487, and has been completed. Findings Between March 30, 2004, and Dec 2, 2008, 368 patients from eight participating centres (five academic centres and three large non-academic teaching hospitals) in the Netherlands were enrolled into this study and randomly assigned to the two treatment groups: 180 to surgery plus neoadjuvant chemoradiotherapy and 188 to surgery alone. Two patients in the neoadjuvant chemoradiotherapy group withdrew consent, so a total of 366 patients were analysed (178 in the neoadjuvant chemoradiotherapy plus surgery group and 188 in the surgery alone group). Of 171 patients who received any neoadjuvant chemoradiotherapy in this group, 162 (95%) were able to complete the entire neoadjuvant chemoradiotherapy regimen. After a median follow-up for surviving patients of 84·1 months (range 61·1–116·8, IQR 70·7–96·6), median overall survival was 48·6 months (95% CI 32·1–65·1) in the neoadjuvant chemoradiotherapy plus surgery group and 24·0 months (14·2–33·7) in the surgery alone group (HR 0·68 95% CI 0·53–0·88; log-rank p=0·003). Median overall survival for patients with squamous cell carcinomas was 81·6 months (95% CI 47·2–116·0) in the neoadjuvant chemoradiotherapy plus surgery group and 21·1 months (15·4–26·7) in the surgery alone group (HR 0·48 95% CI 0·28–0·83; log-rank p=0·008); for patients with adenocarcinomas, it was 43·2 months (24·9–61·4) in the neoadjuvant chemoradiotherapy plus surgery group and 27·1 months (13·0–41·2) in the surgery alone group (HR 0·73 95% CI 0·55–0·98; log-rank p=0·038). Interpretation Long-term follow-up confirms the overall survival benefits for neoadjuvant chemoradiotherapy when added to surgery in patients with resectable oesophageal or oesophagogastric junctional cancer. This improvement is clinically relevant for both squamous cell carcinoma and adenocarcinoma subtypes. Therefore, neoadjuvant chemoradiotherapy according to the CROSS trial followed by surgical resection should be regarded as a standard of care for patients with resectable locally advanced oesophageal or oesophagogastric junctional cancer. Funding Dutch Cancer Foundation (KWF Kankerbestrijding).
Summary
Ticks infest a variety of animal species and transmit pathogens causing disease in both humans and animals worldwide. Tick–host–pathogen interactions have evolved through dynamic processes ...that accommodated the genetic traits of the hosts, pathogens transmitted and the vector tick species that mediate their development and survival. New approaches for tick control are dependent on defining molecular interactions between hosts, ticks and pathogens to allow for discovery of key molecules that could be tested in vaccines or new generation therapeutics for intervention of tick–pathogen cycles. Currently, tick vaccines constitute an effective and environmentally sound approach for the control of ticks and the transmission of the associated tick‐borne diseases. New candidate protective antigens will most likely be identified by focusing on proteins with relevant biological function in the feeding, reproduction, development, immune response, subversion of host immunity of the tick vector and/or molecules vital for pathogen infection and transmission. This review addresses different approaches and strategies used for the discovery of protective antigens, including focusing on relevant tick biological functions and proteins, reverse genetics, vaccinomics and tick protein evolution and interactomics. New and improved tick vaccines will most likely contain multiple antigens to control tick infestations and pathogen infection and transmission.
Summary Background The ideal closure technique of the pancreas after distal pancreatectomy is unknown. We postulated that standardised closure with a stapler device would prevent pancreatic fistula ...more effectively than would a hand-sewn closure of the remnant. Methods This multicentre, randomised, controlled, parallel group-sequential superiority trial was done in 21 European hospitals. Patients with diseases of the pancreatic body and tail undergoing distal pancreatectomy were eligible and were randomly assigned by central randomisation before operation to either stapler or hand-sewn closure of the pancreatic remnant. Surgical performance was assessed with intraoperative photo documentation. The primary endpoint was the combination of pancreatic fistula and death until postoperative day 7. Patients and outcome assessors were masked to group assignment. Interim and final analysis were by intention to treat in all patients in whom a left resection was done. This trial is registered, ISRCTN18452029. Findings Between Nov 16, 2006, and July 3, 2009, 450 patients were randomly assigned to treatment groups (221 stapler; 229 hand-sewn closure), of whom 352 patients (177 stapler, 175 hand-sewn closure) were analysed. Pancreatic fistula rate or mortality did not differ between stapler (56 32% of 177) and hand-sewn closure (49 28% of 175; OR 0·84, 95% CI 0·53–1·33; p=0·56). One patient died within the first 7 days after surgery in the hand-sewn group; no deaths occurred in the stapler group. Serious adverse events did not differ between groups. Interpretation Stapler closure did not reduce the rate of pancreatic fistula compared with hand-sewn closure for distal pancreatectomy. New strategies, including innovative surgical techniques, need to be identified to reduce this adverse outcome. Funding German Federal Ministry of Education and Research.
SNP genotyping arrays have been useful for many applications that require a large number of molecular markers such as high-density genetic mapping, genome-wide association studies (GWAS), and genomic ...selection. We report the establishment of a large maize SNP array and its use for diversity analysis and high density linkage mapping. The markers, taken from more than 800,000 SNPs, were selected to be preferentially located in genes and evenly distributed across the genome. The array was tested with a set of maize germplasm including North American and European inbred lines, parent/F1 combinations, and distantly related teosinte material. A total of 49,585 markers, including 33,417 within 17,520 different genes and 16,168 outside genes, were of good quality for genotyping, with an average failure rate of 4% and rates up to 8% in specific germplasm. To demonstrate this array's use in genetic mapping and for the independent validation of the B73 sequence assembly, two intermated maize recombinant inbred line populations – IBM (B73×Mo17) and LHRF (F2×F252) – were genotyped to establish two high density linkage maps with 20,913 and 14,524 markers respectively. 172 mapped markers were absent in the current B73 assembly and their placement can be used for future improvements of the B73 reference sequence. Colinearity of the genetic and physical maps was mostly conserved with some exceptions that suggest errors in the B73 assembly. Five major regions containing non-colinearities were identified on chromosomes 2, 3, 6, 7 and 9, and are supported by both independent genetic maps. Four additional non-colinear regions were found on the LHRF map only; they may be due to a lower density of IBM markers in those regions or to true structural rearrangements between lines. Given the array's high quality, it will be a valuable resource for maize genetics and many aspects of maize breeding.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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