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1.
The reticuloendothelial system (RES) influences the outcome of vascular shock and environmental stress. We describe a procedure that employs flow cytometry and 1 μm fluorescent microspheres (FM) to study RES function. FM (2 × 1010 beads/kg) were administered via a jugular cannula in Sprague-Dawley rats. After 15 min, blood and tissues were collected and digested in 15% KOH. Phycoerythrin 1 μm beads were added to each sample as an internal standard and analyzed by flow cytometry. FM were preferentially cleared by the spleen, liver and lung. Clearance was confirmed by fluorescent photomicroscopy. Addition of the internal standard to determine accurately aspiration volume enhanced precision. This procedure offers advantages over other RES clearance methods including bacterial, radioactive or carbon clearance assays. Moreover, this method could enhance accuracy, reproducibility and speed of data collection in particulate transport studies that are based on manual microscopic scanning and FM counting.  相似文献   

2.
As the number of cores per node keeps increasing, it becomes increasingly important for MPI to leverage shared memory for intranode communication. This paper investigates the design and optimization of MPI collectives for clusters of NUMA nodes. We develop performance models for collective communication using shared memory and we demonstrate several algorithms for various collectives. Experiments are conducted on both Xeon X5650 and Opteron 6100 InfiniBand clusters. The measurements agree with the model and indicate that different algorithms dominate for short vectors and long vectors. We compare our shared-memory allreduce with several MPI implementations—Open MPI, MPICH2, and MVAPICH2—that utilize system shared memory to facilitate interprocess communication. On a 16-node Xeon cluster and 8-node Opteron cluster, our implementation achieves on geometric average 2.3X and 2.1X speedup over the best MPI implementation, respectively. Our techniques enable an efficient implementation of collective operations on future multi- and manycore systems.  相似文献   

3.
Measurement of regional organ blood flow by means of fluorescent microspheres (FM) is an accepted method. However, determination of regional portal blood flow (RPBF) cannot be performed by microspheres owing to the entrapment of the spheres in the upstream capillary bed of the splanchnic organs. We hypothesized that an adequate experimental setting would enable us to measure RPBF by means of FM and to analyze its distribution within the pig liver. A mixing chamber for the injection of FM was developed, and its capability to distribute FM homogeneously in the blood was evaluated in vitro. The chamber was implanted into the portal vein of six anesthetized pigs (23.5 +/- 2.9 kg body wt). Three consecutive, simultaneous injections of FM of two different colors into the chamber were performed. Reference portal blood samples were collected by means of a Harvard pump. At the end of the experiment, the liver was explanted and fixed in formalin before dissection. FM were isolated from the tissue samples by an automated process, and fluorescence intensity was determined. Comparison of 5,458 single RPBF values, determined by simultaneously injected FM, revealed good agreement (bias 2.5%, precision 12.7%) and high correlation (r = 0.97, r2 = 0,95, slope = 1.04, intercept = 0.05). Median RPBF was 1.07 +/- 0.78 ml x min(-1) x g(-1). Allocation of the blood flow values to the anatomic regions of the liver revealed a significantly higher RPBF (P = 0.01) in the liver tissue located close to the diaphragm compared with the rest of the organ and a significantly lower RPBF (P = 0.01) in the left liver lobe compared with the median and right lobes. The results show that the model presented makes it possible to measure RPBF by means of FM reliably and that RPBF is distributed heterogeneously in the porcine liver.  相似文献   

4.
为研究发酵豆粕在罗氏沼虾饲料中的适宜用量及替代后可能造成的影响, 以含有30%鱼粉和18%豆粕的饲料为基础饲料(T0组), 分别用2% (T2组)、5% (T5组)、8% (T8组)、15% (T15组)的发酵豆粕等蛋白替代基础饲料中的鱼粉和豆粕(2﹕1), 共配制5种等氮等能的实验饲料。选用初始均重为(0.17±0.02) g的罗氏沼虾在室内水泥池网箱中进行为期64d的养殖实验。结果显示, 发酵豆粕对鱼粉和豆粕的替代量影响罗氏沼虾的生长、血清生化及免疫基因表达。随着发酵豆粕添加量的增加, 增重率和特定生长率呈先升后降的趋势, 都以T8组最高。血清中丙二醛含量、超氧化物歧化酶活力随发酵豆粕添加量的增加均呈先升后降的趋势, 各替代组丙二醛含量均显著高于对照组(P<0.05); 血清谷丙转氨酶、谷草转氨酶活性和总蛋白含量呈先下降后上升的趋势, 且替代组不同程度低于对照组; T15组Toll受体、NF-κB、HSP70转录水平表达量显著高于其他各组(P<0.05)。以上结果表明用不同水平的发酵豆粕替代鱼粉和豆粕, 显著影响罗氏沼虾的生长性能、抗氧化能力及免疫机能; 在实验条件下, 罗氏沼虾饲料中的发酵豆粕最佳使用量为8%。  相似文献   

5.
A general purpose incompressible flow solver, called caffa3d.MBRi, is presented which features a block structured framework to accommodate both a flexible approach to geometry representation and a straightforward implementation of parallel capabilities through the MPI library. Representation of complex geometries can be handled semi automatically through a combination of body fitted blocks of grids and the immersed boundary condition strategy over both Cartesian and body fitted grid blocks. The parallelization strategy is based on the same block structured framework, by means of encapsulated MPI calls performing a set of conceptually defined high level communication tasks. A set of real world applications ranging from bioengineering to microclimate scenarios is presented to demonstrate the capabilities of the solver, which is open source and freely available through the web page.  相似文献   

6.
《PloS one》2013,8(11)

Background

The control arm of PATRICIA (PApillomaTRIal against Cancer In young Adults, NCT00122681) was used to investigate the risk of progression from cervical HPV infection to cervical intraepithelial neoplasia (CIN) or clearance of infection, and associated determinants.

Methods and Findings

Women aged 15-25 years were enrolled. A 6-month persistent HPV infection (6MPI) was defined as detection of the same HPV type at two consecutive evaluations over 6 months and clearance as ≥2 type-specific HPV negative samples taken at two consecutive intervals of approximately 6 months following a positive sample. The primary endpoint was CIN grade 2 or greater (CIN2+) associated with the same HPV type as a 6MPI. Secondary endpoints were CIN1+/CIN3+ associated with the same HPV type as a 6MPI; CIN1+/CIN2+/CIN3+ associated with an infection of any duration; and clearance of infection. The analyses included 4825 women with 16,785 infections (3363 womenwith 6902 6MPIs). Risk of developing a CIN1+/CIN2+/CIN3+ associated with same HPV type as a 6MPI varied with HPV type and was significantly higher for oncogenic versus non-oncogenic types. Hazard ratios for development of CIN2+ were 10.44 (95% CI: 6.96-15.65), 9.65 (5.97-15.60), 5.68 (3.50-9.21), 5.38 (2.87-10.06) and 3.87 (2.38-6.30) for HPV-16, HPV-33, HPV-31, HPV-45 and HPV-18, respectively. HPV-16 or HPV-33 6MPIs had ~25-fold higher risk for progression to CIN3+. Previous or concomitant HPV infection or CIN1+ associated with a different HPV type increased risk. Of the different oncogenic HPV types, HPV-16 and HPV-31 infections were least likely to clear.

Conclusions

Cervical infections with oncogenic HPV types increased the risk of CIN2+ and CIN3+. Previous or concomitant infection or CIN1+ also increased the risk. HPV-16 and HPV-33 have by far the highest risk of progression to CIN3+, and HPV-16 and HPV-31 have the lowest chance of clearance.  相似文献   

7.
To avoid the memory registration cost for small messages in MPI implementations over RDMA-enabled networks, message transfer protocols involve a copy to intermediate buffers at both sender and receiver. In this paper, we propose to eliminate the send-side copy when an application buffer is reused frequently. We show that it is more efficient to register the application buffer and use it for data transfer. The idea is examined for small message transfer protocols in MVAPICH2, including RDMA Write and Send/Receive based communications, one-sided communications and collectives. The proposed protocol adaptively falls back to the current protocol when the application does not frequently use its buffers. The performance results over InfiniBand indicate up to 14% improvement for single message latency, close to 20% improvement for one-sided operations and up to 25% improvement for collectives. In addition, the communication time in MPI applications with high buffer reuse is improved using this technique.  相似文献   

8.
This study was designed to determine the extent to which sensations elicited by discrete electrotactile stimulation can be spatially localized, with a qualitative comparison to mechanical stimulation, in a 2 x 2 electrode array on the fingertip. Electrotactile stimulation was delivered in two modes: (1) same current to all locations (constant) or (2) current adjusted to perceptual threshold of each location (varied). For each stimulus location, subjects were asked to identify the location of the stimulus. Mechanical stimulation of the same locations on the fingerpad was delivered through von Frey hairs (0.07, 0.2 and 0.4 g). The percentage of accurate responses was computed for all stimulation modes. We found that the accuracy of discrimination of stimulus location in both the constant (46%) and varied (40%) electrotactile stimulation modes was significantly higher than chance level (25%; p < 0.01). Furthermore, subjects were significantly more accurate in discriminating electrotactile stimuli in the constant than in the varied mode (p < 0.05). We also found that the accuracy of spatial discrimination was dependent on stimulation site for mechanical, but not electrotactile stimulation. Finally, we found a significant difference in accuracy over the duration of the experiment only for mechanical modes, which may indicate that electrotactile stimuli are less biased over time. These results suggest that, although low in accuracy, human subjects are able to extract spatial information from electrotactile stimuli. Further research is needed to optimize the amount of the information that can be delivered through electrotactile stimulation.  相似文献   

9.
When conditioned honeybees collect sucrose solution delivered at a range of low-profit flow rates for the hive, they increase the pause length between successive visits. If sucrose solution was delivered continuously, it accumulated at the food source in an amount proportional to the pause length and the flow rate of nectar. When the flow rate of sucrose solution was further decreased but kept constant throughout the day, a threshold level was attained in which oscillations in the length of the pauses were observed. The relationship between the amount of accumulated nectar and subsequent pause length at this threshold level can be depicted by means of a power function. The best fit allowed the calculation of the values of parameters that quantitatively describe the control system regulating foraging activity. The importance of foraging pauses as a strategy to cope with changing nectar availability is discussed. Accepted: 7 January 1998  相似文献   

10.
Peng L  Kapp EA  McLauchlan D  Jordan TW 《Proteomics》2011,11(22):4376-4384
Although there are now multiple methods for the analysis of membrane proteomes, there is relatively little systematic characterization of proteomic workflows for membrane proteins. The Asia Oceania Human Proteome Organisation (AOHUPO) has therefore embarked on a Membrane Proteomics Initiative (MPI) using a large range of workflows. Here, we describe the characterization of the MPI mouse liver microsomal membrane Standard using SDS-PAGE prior to in-gel tryptic digestion and LC-ESI-MS/MS. The Na(2) CO(3) wash followed by SDS-PAGE prior to in-gel tryptic digestion and LC-MS/MS strategy was effective for the detection of membrane proteins with 47.1% of the identified proteins being transmembrane proteins. Gene Ontology term enrichment analysis showed that biological processes involving transport, lipid metabolism, cell communication, cell adhesion, and cellular component organization were significantly enriched. Comparison of the present data with the previously published reports on mouse liver proteomes confirmed that the MPI Standard provides an excellent resource for the analysis of membrane proteins in the AOHUPO MPI.  相似文献   

11.
Fibromyalgia is a common chronic pain condition in the population (2–4%), which often is associated with prominent negative consequences with respect to participation in daily activities. There are several reports in the literature concerning the effects of acute experimental pain on motor control. However, a more heterogeneous picture exists in the literature with respect to whether chronic pain conditions affect motor control.This study compares firing rate and conduction velocity (CV) of single motor units (MUs) in the trapezius muscle of fibromyalgia patients (FM) and healthy controls (CON). Multi-channel surface electromyography was used to estimate both MU firing rate and CV because this technique allows simultaneous estimation of both these variables and the measurements are easy and non-invasive. In this study, 29 FM and 30 CON subjects participated and performed isometric shoulder elevations using weights up to 4 kg. No significant differences in the firing rate of MUs in the trapezius muscle were found between the FM and CON groups (95% confidence interval was −1.9 and 1.3 pulses per second). There were no significant differences in CV between the groups at 1 and 2 kg load. However, the FM group had significantly higher CV in contractions without external load (p = 0.004).We were unable to confirm the pain-adaptation model since no differences in firing rate between the two groups were found. CV was significantly higher in FM than in healthy controls; this might be due to alterations in histopathology and microcirculation.  相似文献   

12.
Effective and accurate communication of scientific findings is essential. Unfortunately, scientists are not always well trained in how to best communicate their results with other scientists nor do all appreciate the importance of speaking with the public. Here, we provide an example of how the development of oral communication skills can be integrated with research experiences at the undergraduate level. We describe our experiences developing, running, and evaluating a course for undergraduates that complemented their existing undergraduate research experiences with instruction on the nature of science and intensive training on the development of science communication skills. Students delivered science talks, research monologues, and poster presentations about the ecological and evolutionary research in which they were involved. We evaluated the effectiveness of our approach using the CURE survey and a focus group. As expected, undergraduates reported strong benefits to communication skills and confidence. We provide guidance for college researchers, instructors, and administrators interested in motivating and equipping the next generation of scientists to be excellent science communicators.  相似文献   

13.
In vitro chromosome doubling was induced in octoploid (2n = 58) yacon using oryzalin and colchicine as mitotic spindle inhibitors. Nodal segments of in vitro cultured plants, 5–15 mm long, were exposed to 20, 25, or 30 μM oryzalin and 1, 3, or 5 mM colchicine for 24 or 48 h. The resulting ploidy level was determined by chromosome counting and flow cytometry. Out of 240 nodal segments, 3.33% hexadecaploid (2n = 116) plants were regenerated after the application of oryzalin. The greatest proportions of hexadecaploid plants (1.6%) were obtained after 48 h of 25 μM oryzalin treatment. With the colchicine treatment, only 0.42% hexadecaploid plants were detected and their survival rate was significantly lower in comparison with the oryzalin treatment. In hexadecaploid yacon, significantly higher levels of saccharides were detected (FOS 13.9 g/100 g FM, fructose 4.6 g/100 g FM and glucose 2.1 g/100 g FM) compared to the octoploid control (FOS 5.3 g/100 g FM, fructose 2.9 g/100 g FM and glucose 1.0 g/100 g FM). These results indicate that in vitro treatment of nodal segments with oryzalin solution could be an effective procedure for chromosome doubling and the polyploidy breeding can help to increase the FOS content in the tuberous roots.  相似文献   

14.
几株赤潮甲藻的摄食能力   总被引:2,自引:0,他引:2  
采用荧光标记的方法,在营养盐限制条件下,对6株赤潮甲藻对荧光标记的海洋细菌(FLB)、金藻(FLA)和两种粒径分别为0.5μm和2.0μm的荧光微球(FM0.5和FM2.0)4种摄食对象的摄食进行了比较研究。研究结果表明,除了东海原甲藻对4种摄食对象均没有摄食外,其它5株甲藻,微小亚历山大藻、链状亚历山大藻、塔玛亚历山大藻、海洋原甲藻和微小原甲藻均具有摄食能力,但对摄食对象的选择和摄食率有差异,多数摄食率是在4 h达到最大,白天的摄食能力强于夜间。研究说明了在营养盐限制环境中,有些具有兼性营养能力的甲藻对细菌和/或更小浮游植物的摄食能力可能对维持和促进其生长具有不可忽视的作用。  相似文献   

15.
Fault tolerance in parallel systems has traditionally been achieved through a combination of redundancy and checkpointing methods. This notion has also been extended to message-passing systems with user-transparent process checkpointing and message logging. Furthermore, studies of multiple types of rollback and recovery have been reported in literature, ranging from communication-induced checkpointing to pessimistic and synchronous solutions. However, many of these solutions incorporate high overhead because of their inability to utilize application level information.This paper describes the design and implementation of MPI/FT, a high-performance MPI-1.2 implementation enhanced with low-overhead functionality to detect and recover from process failures. The strategy behind MPI/FT is that fault tolerance in message-passing middleware can be optimized based on an application's execution model derived from its communication topology and parallel programming semantics. MPI/FT exploits the specific characteristics of two parallel application execution models in order to optimize performance. MPI/FT also introduces the self-checking thread that monitors the functioning of the middleware itself. User aware checkpointing and user-assisted recovery are compatible with MPI/FT and complement the techniques used here.This paper offers a classification of MPI applications for fault tolerant MPI purposes and MPI/FT implementation discussed here provides different middleware versions specifically tailored to each of the two models studied in detail. The interplay of various parameters affecting the cost of fault tolerance is investigated. Experimental results demonstrate that the approach used to design and implement MPI/FT results in a low-overhead MPI-based fault tolerant communication middleware implementation.  相似文献   

16.
A world-wide spread forage grass, Medicago sativa, was grown in two open-top chambers maintained at either normal (350 μmol · mol-1) or doubled (700 μmol · mol-1) CO2 concentration, from seedling to maturity. During the whole growth season, ecophysiological measurements and observations were conducted over different phenological stages and the main results were as follows: (1) With similar environmental factors, in terms of RH (relative humidity), irradiance, and watering, a slight shift in temperature (about 0.77℃, averaged over the whole growth season) within the chamber maintained at doubled CO2 did not affect instantaneous physiological processes at leaf level, but had some impacts on the effect of doubled CO2 over a long period. (2) Over the whole growth season, physiological variables showed differences between two chambers. The net photosynthesis of plant grown under higher CO2 increased by 18.7 %, while stomatal conductance fell slightly as compared with that of the control. So was the water use efficiency which was also 30.1% higher than the control. Based on the above results from field studies, we concluded that photosynthetically active radiation (PAR) and RH were the main factors affecting photosynthesis and stomatal behavior. Then we combined a widely accepted model of C3 leaf photosynthesis with an empirical model of stomatal conductance and made some modifications according to our experiments. This model was parameterized using field data sets of net CO2 assimilation, stomatal conductance, intercellular CO2 concentration of plants grown at both doubled and control CO2 levels. Variances of main parameters between two treatments reflected some biochemical changes in leaf cell. The maximum efficiency of light energy conversion (α) increased by 22 % and light-saturated rate of electron transport (Jmax) rose by 15 %. The maximum stomatal conductance was slightly reduced by 8 %. The increases in parameters (α and Jmax) indicate accelerated biochemical processes in leaf cell, which means that the photosynthetic capacity of M. sativa may increase at elevated CO2. These results agree well with biochemical measurements at cell level.  相似文献   

17.
An experimental, microbially enhanced soybean product (MEPRO) was evaluated as a replacement for fishmeal (FM). Assessment of feedstuffs should include estimation of digestibility as well as pig performance and in combination with dietary additives. Digestibility values determined in growing pigs may not apply to nursery pigs; thus, standardized ileal digestibility (SID) of amino acids (AA) in MEPRO and FM were determined using 30±1.6 kg BW ileal-cannulated barrows (n=6) and 9.8±1.2 kg BW barrows (n=37; serial slaughter). Experimental diets included MEPRO, FM and nitrogen free where FM and MEPRO were included as the sole protein source. The SID of AAs was 3% to 5% lower in MEPRO than FM when fed to 30 kg pigs. The SID of arginine and methionine was greater (P<0.05) in MEPRO than FM when fed to 10 kg pigs. The SID of AAs was 12% to 20% lower in FM when fed to 10 v. 30 kg pigs but only 3% to 9% lower in MEPRO. A total of 336 barrows and gilts were weaned at 21 days of age (initial BW=6.1±0.8 kg) and used in a performance trial. Pens of pigs were assigned to one of the six experimental diets (8 pens/diet in two blocks). Treatment diets were fed in Phase I (7 days) and Phase II (14 days) with all pigs fed a common Phase III diet (14 days). Experimental diets included (1) negative control (NEG) containing corn, soybean meal and whey, (2) NEG+acidifier, (3) NEG+FM (POS), (4) POS+acidifier (POS A+), (5) NEG+MEPRO (MEPRO) and (6) MEPRO+acidifier. The FM and MEPRO were included at 7.5% and 5.0% in Phase I and II diets, respectively. Diets were formulated to meet the standard nutrient requirements for weaned pigs. Pig BW and feed disappearance was measured weekly and fecal scores were measured daily for the first 14 days post-weaning as an indicator of post-weaning diarrhea syndrome (PWDS). Performance (BW, daily gain, feed intake and gain : feed) was not significantly different among treatments. Treatment for PWDS occurred on different days in each block. Analysis of fecal score was completed separately by block. Pigs fed the NEG diets had higher (P=0.02) fecal scores than pigs fed the POS diets on days 2 and 3 (block 1) and higher (P<0.05) than pigs fed MEPRO or POS diets and diets with dietary acidifier on days 6 and 3 (block 2). The MEPRO holds promise as an alternative to FM in nursery pig diets.  相似文献   

18.
This paper presents an architecture, implementation, and performance evaluation of an adaptive message-passing system for a heterogeneous wide-area ATM cluster that we call the Adaptive Communication System (ACS). ACS uses multithreading to provide efficient techniques for overlapping computation and communication in wide-area computing. By separating control and data activities, ACS eliminates unnecessary control transfers over the data path. This optimizes the data path and improves the performance. ACS supports several different flow control algorithms, error control algorithms, and multicasting algorithms. Furthermore, ACS allows programmers to select at runtime the suitable communication schemes per-connection basis to meet the requirements of a given application. ACS provides three application communication interfaces: Socket Communication Interface (SCI), ATM Communication Interface (ACI), and High Performance Interface (HPI) to support various classes of applications. The SCI is provided mainly for applications that must be portable to many different computing platforms. The ACI provides services that are compatible with ATM connection oriented services where each connection can be configured to meet the Quality of Service (QOS) requirements of that connection. This allows programmers to fully utilize the benefits of the ATM network. The HPI supports applications that demand low-latency and high-throughput communication services. In this interface, ACS uses read/write trap routines to reduce latency and data transfer time, and to avoid using traditional communication protocols. We analyze and compare the performance of ACS with those of other message-passing systems such as p4, PVM, and MPI in terms of point-to-point, multicasting, and application performance. The benchmarking results show that ACS outperforms other message-passing systems and provides flexible communication services for various classes of applications. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

19.
Luteolysis of corpus luteum, due to un-inhibited PGF(2α) secretion, has been reported to be a cause of early embryonic mortality in dairy animals. The objective of this study was to determine the effects of fish meal (FM) supplementation on the uterine secretion of PGF(2α) and hence establish its supplementation as an antiluteolytic strategy in dairy buffaloes. Five cycling Murrah buffaloes were supplemented with 250g FM daily for 55 days in addition to their routine feed and seven buffaloes were kept as non-supplemented control. After 30 days of FM supplementation, the oestrus was synchronized in all the buffaloes using Ovsynch protocol. On day 15 of synchronized cycle, animals were challenged with oxytocin (OT; 100IU) intravenously and blood samples were collected at 15min interval, 1h before to 4h after OT challenge. The PGF(2α) response was measured as the venous concentration of 13,14-dihydro-15-keto PGF(2α) (PGFM). The mean hourly concentration of PGFM in FM supplemented buffaloes was lower than in the control buffaloes at all the occasions. During peak response (1h post-OT challenge), PGFM concentration was significantly lower (P<0.05) in FM supplemented buffaloes than in the control (197.4±41.7pg/ml versus 326.3±33.5pg/ml, respectively). Also the percent rise in PGFM after OT-challenge in FM supplemented buffaloes was less than the control (11.73% versus 22.47%). The dietary supplementation did not affect the size of corpus luteum (CL) and plasma progesterone concentration. Plasma glucose and total protein concentrations remained within the normal physiological limits during FM supplementation. The present study indicated that supplementing FM decreased the concentrations of PGF(2α) without alterations in the size of CL and plasma progesterone concentrations in dairy buffaloes.  相似文献   

20.
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