Femtosecond time resolved CARS spectroscopy of H2-N2 mixtures in the Dicke regime: Experiments and modeling of velocity effects

International audienceIn this paper, we present measurements and modeling of femtosecond time resolved CARS signal in H2-N2 mixtures at low densities. Three approaches have been used to model the CARS response. The first is the usual sum of Voigt profiles. In the second approach, the speed dependent Voigt profile is used. In the last approach, a new model of the CARS signal is developed which takes into account the velocity changes induced by collisions and the speed dependence of the collisional parameters. The velocity changes are modeled using the Keilson and Storer memory function; the radiator speed dependences of the collisional parameters are determined from their temperature dependences. The results show that the changes of the velocity have important effects for the H2/N2 system at the Dicke density regime

The impact of ocean acidification on the functional morphology of foraminifera

This work was supported by the NERC UK Ocean Acidification Research Programme grant NE/H017445/1. WENA acknowledges NERC support (NE/G018502/1). DMP received funding from the MASTS pooling initiative (The Marine Alliance for Science and Technology for Scotland). MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions.Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism’s survival and fitness.Publisher PDFPeer reviewe

Conformational Instability of Rodlike Polyelectrolytes due to Counterion Fluctuations

The effective elasticity of highly charged stiff polyelectrolytes is studied in the presence of counterions, with and without added salt. The rigid polymer conformations may become unstable due to an effective attraction induced by counterion density fluctuations. Instabilities at the longest, or intermediate length scales may signal collapse to globule, or necklace states, respectively. In the presence of added-salt, a generalized electrostatic persistence length is obtained, which has a nontrivial dependence on the Debye screening length. It is also found that the onset of conformational instability is a re-entrant phenomenon as a function of polyelectrolyte length for the unscreened case, and the Debye length or salt concentration for the screened case. This may be relevant in understanding the experimentally observed re-entrant condensation of DNA.Comment: 8 pages, 4 figure

Оптимизация общего содержания флавоноидов в спиртовом экстракте Persicaria pulchra (Bl.) Soják для ингибирования фермента α-глюкозидазы

Objectives. There has been a rapid increase in the number of diabetic patients since the past few decades in developed and developing countries. This rapid increase is accompanied by alarming costs of treatment. α-Glucosidase inhibitors are one of the most effective drugs employed for the reduction of postprandial hyperglycemia to manage Type 2 diabetes mellitus. Additionally, flavonoids, a group of natural substances, which are widely distributed in plants and possess variable phenolic structures, exhibit outstanding hypoglycemic activity and are considered as potential α-glucosidase inhibitors. In Vietnam, Persicaria pulchra (Bl.) Soják (P. pulchra) is employed in traditional medications. It possesses high flavonoid contents and its anti-diabetes ability has been hypothesized, although it has attracted less attention for investigation. Hence, the aim of this study is to optimize the condition of the P. pulchra extract to obtain the highest total flavonoid content and measure the bioactivities of P. pulchra, such as the anti-α-glucosidase and antioxidant activities.Methods. The effects of the extracting conditions, including the temperature, extraction time, liquid-to-solid ratio (LSR), and ethanol (C2H5OH) concentration, on the total flavonoid content are investigated via experiments and analyzed by the response surface methodology (RSM). Concurrently, the optimal extraction also determines the anti-α-glucosidase and antioxidant activities.Results. The optimal extraction condition for the highest flavonoid content (530 mg quercetin/g) is determined in 60 min, at 53°C, with LSR of 9.46 g/g and C2H5OH concentration of 62%. Moreover, the optimal plant extract exhibits good α-glucosidase inhibition with a half-maximal inhibitory concentration (IC50) of 22.67 mg/mL, compared to the positive control (acarbose −7.77 g/mL). Additionally, P. pulchra is proposed to be a potential antioxidant with an IC50 of ~12.68 µg/mL.Conclusions. The study confirmed the optimal extraction condition of P. pulchra that will obtain the highest total flavonoid content and revealed the potentials of P. pulchra in α-glucosidase inhibition and antioxidation.Цели. В последние десятилетия в развитых и развивающихся странах наблюдается быстрый рост числа больных диабетом, который сопровождается ростом стоимости лечения. Ингибиторы α-глюкозидазы являются одним из наиболее эффективных препаратов, применяемых для снижения постпрандиальной гипергликемии при лечении сахарного диабета 2 типа. Кроме того, флавоноиды, группа природных веществ, широко распространенных в растениях и содержащих различные производные фенола, проявляют значительную гипогликемическую активность и могут служить потенциальными ингибиторами α-глюкозидазы. Во Вьетнаме Persicaria pulchra (Bl.) Soják (P. pulchra) используется в народной медицине. Он обладает высоким содержанием флавоноидов и, предположительно, противодиабетическими свойствами, хотя исследован мало. Таким образом, целью настоящего исследования является оптимизация экстрагирования P. pulchra для получения наиболее высокого общего содержания флавоноидов, а также определение его биологической активности – анти-α-глюкозидазной и антиоксидантной. Методы. Экспериментально исследовано влияние условий экстрагирования, а именно температуры, времени экстракции, соотношения жидкость : твердое вещество и концентрации этанола, на общее содержание флавоноидов с помощью методологии анализа поверхности отклика. Показано, что оптимальные условия экстракции определяют анти-α-глюкозидазную и антиоксидантную активность.Результаты. Найдены оптимальные условия экстракции для получения максимального содержания флавоноидов (530 мг кверцетина/г): время экстракции 60 мин, температура 53 °С, отношение жидкость : твердое вещество 9.46 г/г и концентрация этанола 62%. Растительный экстракт, полученный в оптимальных условиях, проявляет хорошее ингибирование α-глюкозидазы с концентрацией полумаксимального ингибирования (IC50) 22.67 мг/мл по сравнению с положительным контролем (акарбоза – 7.77 г/мл). Выводы. Исследование выявило оптимальные условия экстракции P. pulchra, позволяющие получить наиболее высокое общее содержание флавоноидов, и подтвердило перспективы применения P. pulchra для ингибировании α-глюкозидазы и антиоксидантного окисления

Genome-wide association mapping for root traits in a panel of rice accessions from Vietnam

Background: Despite recent sequencing efforts, local genetic resources remain underexploited, even though they carry alleles that can bring agronomic benefits. Taking advantage of the recent genotyping with 22,000 single-nucleotide polymorphism markers of a core collection of 180 Vietnamese rice varieties originating from provinces from North to South Vietnam and from different agrosystems characterized by contrasted water regimes, we have performed a genome-wide association study for different root parameters. Roots contribute to water stress avoidance and are a still underexploited target for breeding purpose due to the difficulty to observe them. Results: The panel of 180 rice varieties was phenotyped under greenhouse conditions for several root traits in an experimental design with 3 replicates. The phenotyping system consisted of long plastic bags that were filled with sand and supplemented with fertilizer. Root length, root mass in different layers, root thickness, and the number of crown roots, as well as several derived root parameters and shoot traits, were recorded. The results were submitted to association mapping using a mixed model involving structure and kinship to enable the identification of significant associations. The analyses were conducted successively on the whole panel and on its indica (115 accessions) and japonica (64 accessions) subcomponents. The two associations with the highest significance were for root thickness on chromosome 2 and for crown root number on chromosome 11. No common associations were detected between the indica and japonica subpanels, probably because of the polymorphism repartition between the subspecies. Based on orthology with Arabidopsis, the possible candidate genes underlying the quantitative trait loci are reviewed. Conclusions: Some of the major quantitative trait loci we detected through this genome-wide association study contain promising candidate genes encoding regulatory elements of known key regulators of root formation and development

Wandering behaviour prevents inter and intra oceanic speciation in a coastal pelagic fish

Small pelagic fishes have the ability to disperse over long distances and may present complex evolutionary histories. Here, Old World Anchovies (OWA) were used as a model system to understand genetic patterns and connectivity of fish between the Atlantic and Pacific basins. We surveyed 16 locations worldwide using mtDNA and 8 microsatellite loci for genetic parameters, and mtDNA (cyt b; 16S) and nuclear (RAG1; RAG2) regions for dating major lineage-splitting events within Engraulidae family. The OWA genetic divergences (0-0.4%) are compatible with intra-specific divergence, showing evidence of both ancient and contemporary admixture between the Pacific and Atlantic populations, enhanced by high asymmetrical migration from the Pacific to the Atlantic. The estimated divergence between Atlantic and Pacific anchovies (0.67 [0.53-0.80] Ma) matches a severe drop of sea temperature during the Gunz glacial stage of the Pleistocene. Our results support an alternative evolutionary scenario for the OWA, suggesting a coastal migration along south Asia, Middle East and eastern Africa continental platforms, followed by the colonization of the Atlantic via the Cape of the Good Hope.Portuguese Foundation for Science & Technology (FCT) [SFRH/BD/36600/2007]; FCT [UID/MAR/04292/2013, SFRH/BPD/65830/2009]; FCT strategic plan [UID/Multi/04326/2013]info:eu-repo/semantics/publishedVersio

Surveillance des dorsalgies chez les salariés des Pays de la Loire, 2002-2005

International audienc

Aseptic Meningitis in Children: Analysis of 506 Cases

BACKGROUND: Non-polio human enteroviruses are the leading cause of aseptic meningitis in children. The role of enterovirus PCR for diagnosis and management of aseptic meningitis has not been fully explored. METHODOLOGY/PRINCIPAL FINDINGS: A retrospective study was conducted to determine the epidemiological, clinical, and laboratory characteristics of aseptic meningitis and to evaluate the role of enterovirus PCR for the diagnosis and management of this clinical entity. The medical records of children who had as discharge diagnosis aseptic or viral meningitis were reviewed. A total of 506 children, median age 5 years, were identified. The annual incidence rate was estimated to be 17/100,000 children less than 14 years of age. Most of the cases occurred during summer (38%) and autumn (24%). The dominant clinical symptoms were fever (98%), headache (94%) and vomiting (67%). Neck stiffness was noted in 60%, and irritation in 46% of the patients. The median number of CSF cell count was 201/mm(3) with polymorphonuclear predominance (>50%) in 58.3% of the cases. Enterovirus RNA was detected in CSF in 47 of 96 (48.9%) children tested. Children with positive enterovirus PCR had shorter hospitalization stay as compared to children who had negative PCR or to children who were not tested (P = 0.01). There were no serious complications or deaths. CONCLUSIONS: Enteroviruses accounted for approximately one half of cases of aseptic meningitis. PCR may reduce the length of hospitalization and plays important role in the diagnosis and management of children with aseptic meningitis