Differential corticosteroid receptor regulation of mesoaccumbens dopamine efflux during the peak and nadir of the circadian rhythm : a molecular equilibrium in the midbrain?

Corticosteroid receptor modulation of mesoaccumbens dopamine neurotransmission is believed to be a key neurobiological mechanism mediating the effects of stress in addiction. Importantly, nucleus accumbens (NAc) subregions (core and shell) are reported to respond differentially to fluctuating basal levels of glucocorticoids, with dopaminergic responses in the core of the NAc being somewhat impervious to fluctuating levels of glucocorticoids relative to the shell. To investigate the corticosteroid receptor mechanisms mediating basal dopamine efflux in the core of the NAc, we have used chronoamperometry in combination with stearate-modified graphite paste electrodes in urethane anesthetized male Long–Evans rats during the peak and nadir of the circadian cycle. Blockade of ventral tegmental area low-affinity glucocorticoid (GR) or high-affinity mineralocorticoid (MR) receptors with mifepristone (1 μg/μl) or spironolactone (0.2 μg/μl), respectively, indicated that endogenous phase-dependent corticosteroid receptor activation (GRs during peak; MRs during nadir) facilitated extracellular NAc dopamine efflux. Conversely, the alternate receptor's actions appeared inhibitory at these time points (MRs during peak; GRs during nadir). Pharmacological activation of either the GR or MR with corticosterone (2 μg/μl) or aldosterone (0.2 μg/μl), respectively, potentiated NAc dopamine efflux, irrespective of circadian phase. Together, these data suggest that dominant corticosteroid receptor activation stimulates tonic mesoaccumbens dopamine transmission, enabling MRs and GRs to differentially maintain basal NAc dopamine release over the course of the circadian cycle. This points to an important molecular mechanism through which relatively stable NAc core dopamine extracellular levels could be maintained in the face of fluctuating corticosterone circadian rhythms.

Recovery of hypoglycemia awareness in long-standing type 1 diabetes: a multicenter 2 × 2 factorial randomized controlled trial comparing insulin pump with multiple daily injections and continuous with conventional glucose self-monitoring (HypoCOMPaSS)

To determine whether impaired awareness of hypoglycemia (IAH) can be improved and severe hypoglycemia (SH) prevented in type 1 diabetes, we compared an insulin pump (continuous subcutaneous insulin infusion [CSII]) with multiple daily injections (MDIs) and adjuvant real-time continuous glucose monitoring (RT) with conventional self-monitoring of blood glucose (SMBG).

Effect of haematocrit on pump and kidney dysfunction after myocardial revascularization

Objective - Kidney dysfunction is a common complication after cardiac surgery. It occurs in 7 to 31% of the patients. The lowest haematocrit after cardiopulmonary bypass surgery (LHCT) has been identified as a risk factor for kidney dysfunction after cardiac surgery. The aim of this study is to determine whether different levels of haematocrit during cardiopulmonary bypass surgery are related to kidney dysfunction.Methods and results-A prospective study was conducted on consecutive adult patients undergoing myocardial revascularization. Preoperative renal function was assessed by baseline serum creatinine level (CrPre). Peak postoperative creatinine (CrPost) was defined as the highest daily in-hospital postoperative value. Peak fractional change in creatinine (% Delta Cr) was defined as the difference between the CrPre and CrePost represented as a percentage of the preoperative value. The LHTC was defined as the lowest recorded haematocrit prior to weaning from the initial pump run. A category variable was created for haematocrit based on the distribution of values. The category variable had the following cut-off points: less than 23%, 23.1 to 28% and greater than 28.1 %. Lowest haematocrit (26.62 +/- 4.15%), CPB (74.71 +/- 24.90 min), CrPre (1.23 +/- 0.37 mg/dl) and highest CrPost (1.52 +/- 0.47 mg/dl) data varied in near-normal fashion. Statistical significance has been observed in the < 23% lowest haematocrit group (CrIPOD and Cr5POD; P = 0.006) and the 23.1 28% lowest haematocrit level group (CrPre and Cr2POD; P = 0.047). CrPre and Cr5POD did not differ between groups (P > 0.05). The multiple linear regression model confirmed that the determinants for higher %Delta Cr were age, body surface area and preoperative serum creatinine level.Conclusion - The LHTC was not identified as a risk factor for kidney dysfunction after myocardial revascularization.

Pump excited state absorption in holmium-doped fluoride glass

The primary excited state absorption processes relating to the (5)I(6) -> (5)I(7) 3 mu m laser transition in singly Ho(3+)-doped fluoride glass have been investigated in detail using time-resolved fluorescence spectroscopy. Selective laser excitation of the (5)I(6) and (5)I(7) energy levels established the occurrence of two excited state absorption transitions from these energy levels that compete with previously described energy transfer upconversion processes. The (5)I(7) -> (5)I(4) excited state absorption transition has peak cross sections at 1216 nm (sigma(esa)=2.8x10(-21) cm(2)), 1174 nm (sigma(esa)=1x10(-21) cm(2)), and 1134 nm (sigma(esa)=7.4x10(-22) cm(2)) which have a strong overlap with the (5)I(8) -> (5)I(6) ground state absorption. on the other hand, it was established that the excited state absorption transition (5)I(6) -> (5)S(2) had a weak overlap with ground state absorption. Using numerical solution of the rate equations, we show that Ho(3+)-doped fluoride fiber lasers employing pumping at 1100 nm rely on excited state absorption from the lowest excited state of Ho(3+) to maintain a population inversion and that energy transfer upconversion processes compete detrimentally with the excited state absorption processes in concentrated Ho(3+)-doped fluoride glass. (c) 2008 American Institute of Physics.

Carbon dioxide efflux in a rhodic hapludox as affected by tillage systems in southern Brazil

Os solos agrícolas podem atuar como dreno ou fonte de C atmosférico, dependendo do sistema de manejo adotado. Este estudo foi desenvolvido em experimento de longa duração (22 anos), durante o período de 30 dias do outono, com o objetivo de avaliar o impacto de sistemas de preparo de solo (preparo convencional-PC e plantio direto-PD) nas emissões de C-CO2 de um Latossolo Vermelho distrófico, em Cruz Alta, RS. As emissões de C-CO2 do solo foram avaliadas com câmaras dinâmica (Flux Chamber 6400-09, Licor) e estática (com captação em solução alcalina), imediatamente após a colheita da soja. A temperatura e a umidade do solo foram registradas, concomitantemente com as emissões de C-CO2, por meio de sensor de temperatura e TDR manual, respectivamente, integrantes do Licor-6400. Estimou-se que, em 30 dias, uma quantidade equivalente a menos de 30 % do C aportado pelos resíduos de soja foi emitida na forma de C-CO2. As emissões de C-CO2 no solo em PD foram similares às emissões do solo em PC, independentemente do tipo de câmara utilizada. Diferenças entre sistemas de preparo quanto à emissão de C-CO2, avaliadas com a câmara dinâmica, foram verificadas somente a curto prazo (leituras diárias), com o PD apresentando maiores emissões do que o PC no início do período experimental e menores no final. A câmara dinâmica foi mais eficiente do que a estática em captar as alterações das emissões de C-CO2 em função da variação da temperatura e a porosidade preenchida por água (PPA) no solo em PD, as quais explicaram 83 e 62 % das emissões de C-CO2, respectivamente. O fator Q10, que avalia a sensibilidade da emissão de C-CO2 à temperatura do solo, foi estimado em 3,93, indicando alta sensibilidade da atividade microbiana à temperatura do solo durante o outono. As emissões de C-CO2 registradas no solo em PD com a câmara estática foram correlacionadas às da câmara dinâmica, porém com valores subestimados em relação àquela notadamente nos maiores valores de fluxo. em condições de baixa temperatura e PPA, o preparo de solo induziu limitado incremento de emissão de C-CO2.

Soil CO2 efflux following rotary tillage of a tropical soil

Stopping the increase of atmospheric CO2 level is an important task and information on how to implement adjustments on tillage practices could help lower Soil CO2 emissions would be helpful. We describe how rotary tiller use on a red latosol affected Soil CO2 efflux. The impact of changing blade rotation speed and rear shield position on soil CO2 efflux was investigated. Significant differences among treatments were observed up to 10 days after tillage. Cumulative CO2 efflux was as much as 40% greater when blade rotation of 216 rpm and a lowered rear shield was compared to blade rotation of 122 rpm and raised shield. This preliminary work suggests that adjusting rotary tiller settings could help reduce CO2 efflux close to that of undisturbed soil, thereby helping to conserve soil carbon in tropical environments. (C) 2004 Elsevier B.V. All rights reserved.

Drying kinetics of tomato by using electric resistance and heat pump dryers

Drying kinetics of tomato was studied by using heat pump dryer (HPD) and electric resistance dryers with parallel and crossed airflow. The performance of both systems was evaluated and compared and the influence of temperature, air velocity, and tomato type on the drying kinetics was analyzed. The use of HPD showed to be adequate in the drying process of tomatoes, mainly in relation to the conversion rate of electric energy into thermal energy. The heat pump effective coefficient of performance (COPHT,EF) was between 2.56 and 2.68, with an energy economy of about 40% when compared to the drying system with electric resistance. The Page model could be used to predict drying time of tomato and statistical analysis showed that the model parameters were mainly affected by drying temperature.

Installation of a getter vacuum pump in cathode-anode region of a high-power klystron amplifier - Propose and feasible

The possibility to install a getter vacuum pump and its feasible in the anode of a high-power klystron amplifier is investigated in order to decrease of the pressure in the gun and consequently increasing its lifetime. The study is conducted using a 1.3 GHz, 100 A and 240 kV high-power klystron with five reentrant coaxial cavities, assembled in a cylindrical drift tube 1.2 m long. This work takes into account the specific conductance of components of gun and all important gas sources, like the degassing of the drift tube, the cavity walls, the cathode, the anode, and the collector, as well the position and pumping speed of the getter vacuum pump in anode region. © 2006 IEEE.

Analysis of renal function after on and off pump coronary artery bypass grafting

Cardiopulmonary bypass (CPB) is often associated with renal dysfunction, as measured by plasma creatinine levels and hemodialysis rates. Aim. To compare creatinine clearance (CrCl), estimated with the Cockroft and Gault formula, between patients undergoing off-pump coronary artery bypass grafting (OPCAB) versus on-pump CABG (on-CAB). Material and methods. Between April 2008 and April 2009, 119 patients underwent coronary bypass graft surgery. Fifty-eight (58) of these patients underwent OPCAB while 61 had on-CAB. Creatinine clearance, plasma creatinine levels, and clinical outcome were compared between the groups. A creatinine clearance value of 50 mL/minute was accepted as the lowest limit of normal renal function. Results. There were two hospital deaths caused by sepses after pulmonary infection. Creatinine clearance (Preoperative OPCAB 73,64±33,72 x on-CAB 75,70±34,30mL/min; discharge OPCAB 75,73±35,07 x on-CAB 79,07±34,71 mL/ min; p=0,609), and creatinine levels (Preoperative OPCAB 1,04±0,38 x on-CAB 1,13±0,53 mg/dL; discharge OPCAB 1,12±0,79 x on-CAB 1,04±0,29mg/dL; p=0,407) did not show statistically inter-group differences. Conclusion. Deterioration in renal function is associated with higher rates of postoperative complications. No significant difference in CrCl could be demonstrated between the groups.

Hot spots, hot moments, and spatio-temporal controls on soil CO2 efflux in a water-limited ecosystem

Soil CO2 efflux is the primary source of CO2 emissions from terrestrial ecosystems to the atmosphere. The rates of this flux vary in time and space producing hot moments (sudden temporal high fluxes) and hot spots (spatially defined high fluxes), but these high reaction rates are rarely studied in conjunction with each other. We studied temporal and spatial variation of soil CO2 efflux in a water-limited Mediterranean ecosystem in Baja California, Mexico. Soil CO2 efflux increased 522% during a hot moment after rewetting of soils following dry summer months. Monthly precipitation was the primary driver of the seasonal trend of soil CO2 efflux (including the hot moment) and through changes in soil volumetric water content (VWC) it influenced the relationship between CO2 efflux and soil temperature. Geostatistical analyses showed that the spatial dependence of soil CO2 efflux changed between two contrasting seasons (dry and wet). During the dry season high soil VWC was associated with high soil CO2 efflux, and during the wet season the emergence of a hot spot of soil CO2 efflux was associated with higher root biomass and leaf area index. These results suggest that sampling designs should accommodate for changes in spatial dependence of measured variables. The spatio-temporal relationships identified in this study are arguably different from temperate ecosystems where the majority of soil CO2 efflux research has been done. This study provides evidence of the complexity of the mechanisms controlling the spatio-temporal variability of soil CO2 efflux in water-limited ecosystems. (C) 2014 Elsevier Ltd. All rights reserved.

Biogeochemistry of a deep-sea whale fall: sulfate reduction, sulfide efflux and methanogenesis

Deep-sea whale falls create sulfidic habits Supporting chemoautotrophic communities, but microbial processes underlying the formation Of Such habitats remain poorly evaluated. Microbial degradation processes (sulfate reduction, methanogenesis) and biogeochemical gradients were studied in a whale-fall habitat created by a 30 t whale carcass deployed at 1675 m depth for 6 to 7 yr on the California margin. A variety of measurements were conducted including photomosaicking, microsensor measurements, radio-tracer incubations and geochemical analyses. Sediments were Studied at different distances (0 to 9 in) from the whale fall. Highest microbial activities and steepest vertical geochemical gradients were found within 0.5 m of the whale fall, revealing ex situ sulfate reduction and in vitro methanogenesis rates of up to 717 and 99 mmol m(-2) d(-1), respectively. In sediments containing whale biomass, methanogenesis was equivalent to 20 to 30%, of sulfate reduction. During in vitro sediment studies, sulfide and methane were produced within days to weeks after addition of whale biomass, indicating that chemosynthesis is promoted at early stages of the whale fall. Total sulfide production from sediments within 0.5 m of the whale fall was 2.1 +/- 3 and 1.5 +/- 2.1 mol d(-1) in Years 6 and 7, respectively, of which similar to 200 mmol d(-1) were available as free sulfide. Sulfate reduction in bones was much lower, accounting for a total availability of similar to 10 mmol sulfide d(-1). Over periods of at least 7 yr, whale falls can create sulfidic conditions similar to other chemosynthetic habitats Such as cold seeps and hydrothermal vents.

Computational and experimental characterization of a low-cost piezoelectric valveless diaphragm pump

Flow pumps act as important devices in areas such as Bioengineering, Medicine, and Pharmacy, among other areas of Engineering, mainly for delivering liquids or gases at small-scale and precision flow rate quantities. Principles for pumping fluids based on piezoelectric actuators have been widely studied, since they allow the construction of pump systems for displacement of small fluid volumes with low power consumption. This work studies valveless piezoelectric diaphragm pumps for flow generation, which uses a piezoelectric ceramic (PZT) as actuator to move a membrane (diaphragm) up and down as a piston. The direction of the flow is guaranteed by valveless configuration based on a nozzle-diffuser system that privileges the flow in just one pumping direction. Most research efforts on development of valveless flow pump deal either with computational simulations based on simplified models or with simplified physical approaches based on analytical models. The main objective of this work is the study of a methodology to develop a low-cost valveless piezoelectric diaphragm flow pump using computational simulations, parametric study, prototype manufacturing, and experimental characterization. The parametric study has shown that the eccentricity of PZT layer and metal layer plays a key role in the performance of the pump.