Spring molybdenum enrichment in scallop shells: a potential tracer of diatom productivity in temperate coastal environments (Brittany, NW France)

Skeletal molybdenum/calcium ([Mo]/[Ca])_shell ratios were examined in shells of the Great Scallop <i>Pecten maximus</i> collected in temperate coastal environments of Western Europe (42 to 49&deg; N). These ratios were determined by quantitative LA-ICP-MS analyses of daily striae taken every third day (i.e. a temporal resolution of 3 days) in 36 flat valves (2-years old; 3 shells/year). Variations of ([Mo]/[Ca])_shell ratios were significant and reproducible for scallops from the same population, from different years (1998–2004) and temperate coastal locations (NW France). The [Mo]/[Ca])_shell ratios exhibit typical profiles characterized by a background content, below the detection limit for this method (&lt;0.003 &mu;mol/mol) for most of the shell growth period, which is punctuated by a significant transient enrichment (0.031–2.1 &mu;mol/mol) mainly occurring from May to June. The Bay of Brest (France) was investigated in particular because of its long term observations on scallop communities, environmental variables, and high resolution analyses of dissolved Mo in bottom seawater in 2000. In 2000, dissolved Mo exhibited a significant increase in concentration just preceding the maximum ([Mo]/[Ca])_shell ratio. Both the intense monitoring survey in 2000 and over the 7-year period indicates that the ([Mo]/[Ca])_shell maximum is directly influenced by spring changes of environmental conditions at the sediment water interface (SWI), occurring subsequent to the intense and periodic spring bloom. Spring maxima of ([Mo]/[Ca])_shell ratios are closely correlated to the extent of silicic acid and nitrate depletion in seawater between winter and late spring (<i>r</i>²=0.878 and 0.780, <i>p</i><0.05, <i>n</i>=6) that reflects diatom uptake and productivity in the Bay of Brest. The Mo inputs in bottom waters and subsequent shell enrichment are thus suggested to be directly or indirectly influenced by such biogenic material input at the SWI. The [Mo]/[Ca])_shell records thus reveal unexpected biogeochemical cycles of Mo influenced by coastal spring productivity, faithfully recorded in scallop shells

Identification and discussion of the main factors affecting fertility: the impact of the per capita monetary income indicator on the fertility rate of the population of the Russian Federation

The purpose of the study is to study and establish the nature of the relationship between the level of well-being of the population and the birth rate.Цель исследования – изучить и установить характер взаимосвязи между уровнем благосостояния населения и уровнем рождаемости

Neprilysin inhibirors in pharmacotherapy of various diseases

Current research illustrates the role of neprilysin as a possible point of application in the treatment of a number of diseases, including heart failure, diabetes mellitus and Alzheimer's disease. The article describes these studies with an emphasis on the role of neprilysin in these diseases pathogenesisСовременные исследования иллюстрируют роль неприлизина в качестве возможной точки приложения в терапии ряда заболеваний, среди которых сердечная недостаточность, сахарный диабет и болезнь Альцгеймера. В статье приведено описание этих исследований с указанием роли неприлизина в патогенезе обозначенных заболевани

Capabilities of traditional integrated approach to diagnosis and management of acute pulmonary embolism

The work is dedicated to one of the most dangerous disorders - acute pulm onary em bolism (A P E). The authors analyze the experience of treating 77 patients with A PE of moderate and low risk at the city hospital. Objective - to improve the diagnosis and treatment of APE by analyzing features of diagnosis and treatment of pulm onary embolism of moderate and low risk, based on the integrated evaluation of classical param eters, alw ays available in non-specialized health facilities. It is shown that the greatest difficulties arise in diagnosing the presence of obstruction of medium and small branches of the pulm onary artery. This fact leads to the delayed hospitalization of patients, as well as late beginning of treatment. In a conventional health facility where there are no conditions for the implementation of high-tech diagnostic methods, doctors should verify the diagnose of A PE using routine combination of methods: clinical symptoms, physical examination, indicators of coagulation system , ECG and X-ray, ECHO-cardiography. The unspecialized hospital provides conservative treatment with the help of direct anticoagulants, followed by prolonged use of indirect anticoagulants or antiagregants.Работа посвящена одной из опаснейших патологий - тромбоэмболии легочной артерии (ТЗ/1А). Авторы анализируют опыт лечения 77 пациентов с ТЭЛ А умеренного и низкого риска в условиях неспециализированного ЛПУ. Цель исследования - улучшить диагностику и лечение ТЭЛА, проанализировав особенности течения ТЭЛА умеренного и низкого риска, на основе интегральной оценки классических параметров, всегда имеющихся в распоряжении неспециализированных ЛПУ. Показано, что наибольшие трудности в диагностике возникают при наличии обструкции средних и мелких ветвей легочной артерии. Это приводит к тому, что госпитализация больных запаздывает, равно как и лечение. В условиях обычного ЛПУ, где нет условий для осуществления высокотехнологичных методов диагностики, практическим врачам следует проявлять максимальную тромбоэмбологенную настороженность и верифицировать диагноз по совокупности рутинных методов: клиническая симптоматика, физикальное обследование, показатели состояния свертывающей системы, ЭКГ и рентгенологическое исследование, ЭХО-кардиография. В неспециализированном стационаре методом выбора является сугубо консервативное лечение антикоагулянтными препаратами прямого действия с последующим пролонгированным использованием непрямых антикоагулянтов или дезагрегантов

Direct determination of trace elements in powdered samples by in-cell isotope dilution femtosecond laser ablation ICPMS

A method has been developed for the direct and simultaneous multielement determination of Cu, Zn, Sn, and Pb in soil and sediment samples using femtosecond laser ablation inductively coupled plasma mass spectrometry (fs-LA-ICPMS) in combination with isotope dilution mass spectrometry (IDMS). The in-cell isotope dilution fs-LA-ICPMS method proposed in this work was based on the quasi-simultaneous ablation of the natural abundance sample and the isotopically enriched solid spike, which was performed using a high repetition rate laser and a fast scanning beam device in a combined manner. Both the sample preparation procedure and the total analysis time have been drastically reduced, in comparison with previous approaches, since a unique multielement isotopically enriched solid spike was employed to analyze different powdered samples. Numerous experimental parameters were carefully selected (e.g., carrier gas flow rate, inlet diameter of the ablation cell, sample translation speed, scanner speed, etc.) in order to ensure the complete mixing between the sample and the solid spike aerosols. The proposed in-cell fs-LA-ICP-IDMS method was tested for the analysis of two soil (CRM 142R, GBW-07405) and two sediment (PACS-2, IAEA-405) reference materials, and the analysis of Cu, Zn, Sn, and Pb yielded good agreement of usually not more than 10% deviation from the certified values and precisions of less than 15% relative standard deviation. Furthermore, the concentrations were in agreement not only with the certified values but also with those obtained by ICP-IDMS after the microwave-assisted digestion of the solid samples, demonstrating therefore that in-cell fs-LA-ICP-IDMS opens the possibility for accurate and precise determinations of trace elements in powdered samples reducing the total sample preparation time to less than 5 min. Additionally, scanning electron microscope measurements showed that the aerosol generated by in-cell fs-LA-ICP-IDMS predominantly consisted of linear agglomerates of small particles (in the order of few tens of nanometers) and a few large spherical particles with diameters below 225 nm

Manganese in the shell of the bivalve Mytilus edulis: Seawater Mn or physiological control?

Manganese in the shell calcite of marine bivalves has been suggested to reflect ambient seawater Mn concentrations, thus providing a high-resolution archive of past seawater Mn concentrations. However, a quantitative relationship between seawater Mn and shell Mn/Ca ratios, as well as clear understanding of which process(es) control(s) shell Mn/Ca, are still lacking. Blue mussels, Mytilus edulis, were grown in a one-year duration field experiment in the Menai Strait, U.K., to study the relationship between seawater particulate and dissolved Mn2+ concentrations and shell calcite Mn/Ca ratios. Shell Mn/Ca showed a well-defined intra-annual double-peak, with maximum values during early spring and early summer and low values during autumn and winter. Seawater particulate Mn peaked during winter and autumn, with a series of smaller peaks during spring and summer, whereas dissolved Mn2+ exhibited a marked single maximum during late-spring to early-summer, being low during the remainder of the year. Consequently, neither seawater particulate Mn nor dissolved Mn2+ concentrations explain the intra-annual variation of shell Mn/Ca ratios. A physiological control on shell Mn/Ca ratios is evident from the strong similarity and timing of the double-peaked intra-annual variations of Mn/Ca and shell growth rate (SGR), the latter corresponding to periods of increased metabolic activity (as indicated by respiration rate). It is thus likely that in M. edulis SGR influences shell Mn/Ca by altering the concentration or activity of Mn2+ within the extra-pallial fluid (EPF), by changing the flux of Mn into or the proportion of protein bound Mn within the EPF. By linking shell Mn/Ca ratios to the endogenous and environmental factors that determine growth and metabolic activity, this study helps to explain the lack of a consistent relationship between shell Mn/Ca in marine bivalve shell calcite and seawater particulate and dissolved Mn2+ concentrations. The use of Mn content from M. edulis shell calcite as a proxy for the dissolved and/or particulate Mn concentrations, and thus the biogeochemical processes that control them, remains elusive

Habitable Underwater Hyperbaric Facilities: Respiratory Balance in the Human Organism During Adapting to Saturation Nitrogen-Oxygen Hyperbaria

There were evaluated responses of the respiratory system to changes in the variables of the external environment under increased pressure. To the model of professional underwater human activity underwater served the conditions of full saturation in compressed air or nitrogen-oxygen gas mixtures. Technical devices were presented by a number of underwater laboratories, mounted at the bottom (Ikhtiander-66, 67 and 68), hyperbaric chambers, submersible drilling rigs (Bur-1 and 2), and an autonomous diving Ikhtiander-2 for a long stay in the water. Studies of respiratory gases mass transport conditions in man showed than within the pressure range of 0.25-1.1 MPa at density of moderate hyperoxic and nitrogen-helio-oxygen environment up to 14 kg/m3 oxygen and carbon dioxide regimes of the organism come to a new functional level which provides the adaptation to the extremal conditions. It is determined that an increase of physiological dead breathing space, a decrease of the rate of the O2 diffusion through the alveole-capillary barrier, intensification of unevenness of ventilator-perfusional relations in lungs and an increase of blood shunting in lungs are the main respiratory mechanisms which regulate mass transfer of O2 and CO2 in man under hyperbaria. The leading hemodynamic mechanism is the retention of volume blood circulation and cardiac output. It is studied how the compression rate, high partial pressures of oxygen and nitrogen, microclimate parameters in inhabited hypebaric chambers influence changes of functional breathing system. Absence of hypoxic state is proved in man (full saturation of man with nitrogen) under normoxia in nitrogen-oxygen environment with the density 6.34 kg/m3. These are also the data about accelerated rehabilitation of divers using the method of active adaptation o high altitudes. Basic directions in physiological studies of functional breathing system under increased pressure of gas and water environment are described.Eksperymenty polegały na ocenie reakcji układu oddechowego na zmiany zmiennych środowiska zewnętrznego pod zwiększonym ciśnieniem. Badania dotyczyły wpływu na organizm ludzki całkowitego nasycenia mieszanin sprężonego powietrza lub azotu i tlenu. Szereg laboratoriów podwodnych zaprezentowało różnego rodzaju urządzenia techniczne do stosowania w środowisku podwodnym (Ikhtiander-66, 67 i 68). Należą do nich: komory hiperbaryczne, wiertnice podwodne (Bur-1 i 2) oraz autonomiczny kombinezon nurkowy przeznaczony do długotrwałych pobytów w wodzie. Badania dotyczące warunków transportu masowego gazów oddechowych u człowieka wykazały, że w zakresie ciśnień 0,25-1,1 MPa, przy gęstościach środowiska umiarkowanie hiperoksyjnego i azotowo-heliotlenowego do 14 kg/m3 w reżimie tlenowym i dla poziomu dwutlenku węgla w organizmie, osiągają one nowy poziom funkcjonalny, który ułatwia adaptację do warunków ekstremalnych. Stwierdzono, że zwiększenie fizjologicznej martwej przestrzeni oddechowej, zmniejszenie szybkości dyfuzji O2 poprzez barierę pęcherzykowo-kapilarną, nasilenie nierównomierności relacji powietrzno-perfuzjalnych w płucach oraz wzrost przepływu krwi w płucach są głównymi mechanizmami oddechowymi regulującymi masowy transfer O2 i CO2 u człowieka w warunkach hiperbarii. Głównym mechanizmem hemodynamicznym jest utrzymanie odpowiedniego krążenia krwi i rzutu serca. Zbadano, w jaki sposób stopień sprężania, wysokie ciśnienia cząstkowe tlenu i azotu oraz parametry mikroklimatyczne w komorach hiperbarycznych wpływają na zmiany w rozwoju układu oddechowego. Brak stanu niedotlenienia u człowieka (pełne nasycenie człowieka azotem) wykazano w warunkach normoksji w środowisku azot-tlen o gęstości 6,34 kg/m3. Dane te dotyczą również przyspieszonej rehabilitacji nurków z zastosowaniem metody aktywnej adaptacji na dużych wysokościach. Opisano podstawowe kierunki badań fizjologicznych czynnościowych układów oddechowych w warunkach zwiększonego ciśnienia gazu i środowiska wodnego

Habitable Underwater Hyperbaric Facilities: Respiratory Balance in the Human Organism During Adapting to Saturation Nitrogen-Oxygen Hyperbaria

There were evaluated responses of the respiratory system to changes in the variables of the external environment under increased pressure. To the model of professional underwater human activity underwater served the conditions of full saturation in compressed air or nitrogen-oxygen gas mixtures. Technical devices were presented by a number of underwater laboratories, mounted at the bottom (Ikhtiander-66, 67 and 68), hyperbaric chambers, submersible drilling rigs (Bur-1 and 2), and an autonomous diving Ikhtiander-2 for a long stay in the water

P–T–X conditions on the genesis of orogenic Au (As, Bi, Ag) deposit in metasedimentary rocks of the Buracão Area, Araí Group, Brasília Fold Belt, Brazil

International audienceThe orogenic Au (As, Bi, Ag) mineralization (up to 31 g/t) of the Buracão area is hosted in the metasedimentary Paleo–Mesoproterozoic Traíras Formation, Araí Group, Brasília Fold Belt, Brazil. In order to discuss the P–T–X conditions that generated this mineralization, we present mineralogical, geochemical and fluid inclusion data of veins, gold and wall rocks. Coupled with previous structural data these additional data allow us to link metamorphism and deformation with fluid migration and ore genesis. The integration of fluid inclusion microthermometry with mineral geothermobarometers and structures show that rocks of the study area evolved from: (i) syn–D1a metamorphic peak (400–560 °C, <6 kbar), through to the (ii) development of syn–D1b type I barren veins from low salinity H2O–NaCl fluids during syn– to late–metamorphic peak; and to the (iii) development of syn–D2a type II veins with the pyritic ore precipitation from low to high salinity H2O–CO2–CH4–NaCl ± HCO3 fluids during post–metamorphic peak (345–285 °C, 2.7–1.6 kbar).The high fineness gold nuggets accompanied by As, Bi and Ag within pyrite–arsenopyrite–bismuthinite association in the pyritic ore allows the Buracão area to be classified as “a gold-only orogenic ore deposit”. Fluid inclusion compounds and the enrichment of As, Bi, Pb, Cu, Te, Se and Ag in pyrite from the pyritic ore point out to metamorphism of carbonaceous phyllites and carbonate rocks of the Traíras Formation as a source for ore–forming fluids. We suggest that sulfur and gold in these fluids were derived by metamorphism of sedimentary rocks and conversion of pyrite into pyrrhotite in a metamorphic–hydrothermal system. The Au(HS)2−–bearing fluids percolated along intrabasinal D2a regional shear zones through the Traíras Formation towards the Buracão area, where they precipitated type II ore–bearing veins within local structures. The ore precipitation was induced by contrasting fO2–fS2 related to the interaction between the sulfur-bearing fluid and host magnetite–graphite phyllites. The lithological control is represented by a series of reactions such as 2FeO(in silicates/magnetite) + 4Au(HS)2−(aq) + 4H+(aq) ↔ 2FeS2(s) + 4Au(s) + 4H2S(aq) + 2H2O(l).The deposits of the Buracão area and other orogenic gold deposits hosted in metasedimentary rocks in the Brasília Fold Belt and worldwide confirm the potential of ore genesis in zones that do not show any relation with (meta)igneous rocks, thus, expanding the exploration possibilities in metasedimentary successions