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1.
Neurokinin-1 receptor (NK1R) and mu-opioid receptor (muOR) agonists affected respiratory rhythm when injected directly into the preB?tzinger Complex (preB?tC), the hypothesized site for respiratory rhythmogenesis in mammals. These effects were mediated by actions on preB?tC rhythmogenic neurons. The distribution of NK1R+ neurons anatomically defined the preB?tC. Type 1 neurons in the preB?tC, which have rhythmogenic properties, expressed both NK1Rs and muORs, whereas type 2 neurons expressed only NK1Rs. These findings suggest that the preB?tC is a definable anatomic structure with unique physiological function and that a subpopulation of neurons expressing both NK1Rs and muORs generate respiratory rhythm and modulate respiratory frequency.  相似文献   

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Xiao C  Xu X  Liu S  Wang T  Dong W  Yang T  Sun Z  Dai D  Xu X  Zhang DH  Yang X 《Science (New York, N.Y.)》2011,333(6041):440-442
Quantum dynamical theories have progressed to the stage in which state-to-state differential cross sections can now be routinely computed with high accuracy for three-atom systems since the first such calculation was carried out more than 30 years ago for the H + H(2) system. For reactions beyond three atoms, however, highly accurate quantum dynamical calculations of differential cross sections have not been feasible. We have recently developed a quantum wave packet method to compute full-dimensional differential cross sections for four-atom reactions. Here, we report benchmark calculations carried out for the prototypical HD + OH → H(2)O + D reaction on an accurate potential energy surface that yield differential cross sections in excellent agreement with those from a high-resolution, crossed-molecular beam experiment.  相似文献   

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In this paper the application of a cleaning system which was made up of a centrifugal fan with double channel and one sieve to 4LZ-3.5 combine was introduced.This cleaning system with double channel compared with the traditional air-sieve cleaning system of combines may omit one two sieves and simplify the transmission mechanism.It is also compared with the present cleaning systom with double channel applied to some combines,such as the Commandor 112CS/228CS combines of Claas Corporation in Germany and the MAXIMIZER^TM combines of John Deere company in U.S.A.It may omit one sieve and the precleaner and simlity the transmission mechanism.The measuring results indicated that the cleaning ratio of wheat grain is 99.1% and the cleaning loss ratio of wheat is 0.17% when the feed rate is 4.01kg/s.  相似文献   

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Thirteen fractions from the pathogenic plant fungus Setosphaeria turcica race 1 were separated and collected using high performance liquid chromatography (HPLC). Their toxic activities were assayed through leaf puncturing on corn differentials (OH43, OH43Ht1, OH43Ht2, and OH43HtN), and the results revealed that eight fractions were toxic and fraction 6 was specifically toxic to OH43Ht1, which could be taken as a gene-selective toxin fraction. Fraction 6 was finely purified via HPLC and condensed by freeze desiccation. Its chemical structure was analyzed with EI-MS, IR, HMBC, ^1H-NMR, and two-dimensional NMR. The results suggested that fraction 6 contained an unsaturated double bond, carbonyl and methylene groups with molecular weight of 142.  相似文献   

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The brush border membrane vesicles (BBMVs) in midgut of Helicoverpa armigera were successfully separated, and most of the Aminopeptidase N (APN) activities in BBMV were preserved. The 3-[(3-chlor-amidopropyl) dimethylammonio]-l-propane-sulphonate (CHAPS) can enhance the dissolution of BBMV, and phosphatidylinositol-specific phosopholipase C (PI-PLC) can cleave the APN from midgut membrane. The APN was primarily purified using a Mono-Q column. The results of immunoblotting showed that the 120 and 170 kDa proteins in the BBMV could bind CrylAc, and 120 kDa APN was a glycosylphosphalidylinositol(GPI)-anchored protein. Two Bt-resistant strains (Bt-P, Bt-M) were obtained after being selected for more than five years in laboratory using Bt insecticides and Bt transgenic cotton incorporated into diet separately. The resistance of Bt-P and Bt-M were 1 083.3 and 48.7 times that of susceptible strain. The genes encoding APNI in midgut of susceptible and resistant H.armigera were cloned by PCR and RACE techniques. The inferred amino acid sequences of APNI possessed the common character of APN family in insects. In comparison with APNI in susceptible strain, three nucleotide mutations were observed in the APNI of Bt-M strain and resulted in two amino acid replace in the putative protein sequences, and eight nucleotide mutations were observed in Bt-P strain and resulted in five amino acid replace.  相似文献   

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In China, the purity of maize hybrid strain is discomforting to the development of seed industrialization. Finding a new method for reproduction of maize hybrid strain is necessary. In this study, using particle bombardment, barstar gene was transferred into maize inbred line 18-599 (White), which is an antiviral and high quality maize inbred line. By molecular detection of the anther of transgenic maize, two plants transferred with barstar gene were gained in this study, which are two restorer lines. The two plants showed normal male spike, and lively microspores. But the capacity of the two restorer lines should be studied in the future. The aim of this study is to find a new method of reproduction of maize hybrid strain using engineering restorer lines and engineering sterility lines by gene engineering technology.  相似文献   

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Experiments were performed to evaluate the efficiency of inhibition of HSP70 gene expression by antisense oligonucleotides complementary to the mRNA of HSPTO and to test the effects of inhibition of HSP70 gene expression on subsequent embryonic sensitivity to heat shock. The results showed that transfection of pre-implantation embryos at 4-cell stage with 5 μM antisense oligo had no effect on in vitro blastocyst development. However, transfection with 10 to 40 μM antisense oligo had reduced in vitro blastocyst development to 15, 10% and 0; For the embryos which exposed to 40 μM As arrested at the 16-cell stage, there was no blastocyst formation within the heat shock groups. In contrast, transfection had no effect on embryonic sensitivity to heat shock, above 25% of embryos developed to blastocyst stage in control groups.  相似文献   

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Ultrasonic acoustic emissions (AEs) from leaf xylem of both water stressed and well watered potted winter wheat (Triticum aestivum L.) plants during drought and rewatering cycle were investigated with a ‘PCI-2 Based AE System' (Physical Acoustics Corp. New Jersey, USA) for estimation of leaf xylem cavitation and embolism. Very few AEs occurred in xylem of wheat leaves in well-watered plant, and also in plant subject to mild and moderate soil water stress conditions over the first 4 d of the drought cycle. Great amounts of AEs have occurred since d 5 of the drought cycle as plant showed obvious leaf curling, indicating significant cavitation in leaf xylem on plant exposed to severe soil water deficit. At this point, relative soil water content (RSWC) and leaf xylem pressure (ψ1) dropped to 24.0-26.5% and -1.92 MPa, respectively, with reductions in leaf stomatal conductance (gs), leaf transpiration (Tr) and leaf CO2 assimilation rate (A) of as much as 69.8, 60.7 and 46.5%, respectively. The effect of soil water deficit was in the order gs 〉 Tr 〉 A 〉 AE. Waveform physical property parameters such as amplitude, counts, rise time, duration, absolute energy and signal strength were analyzed. These parameters varied within very broad ranges, with frequency distribution of most parameters being well fitted by the exponential function y = yo- A exp (-x/t). The proportion of stronger AE signals rose as soil dehydrated. While AEs occurrence in water stressed plant remained higher than in well-watered control at the following day after rewatering, waveform signal strength and related physical property parameters dropped immediately to that of control. Difference in AEs occurrence characterization between field-grown and potted wheat leaves was discussed.  相似文献   

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The emerging concept of food sovereignty refers to the right of communities, peoples, and states to independently determine their own food and agricultural policies. It raises the question of which type of food production, agriculture and rural development should be pursued to guarantee food security for the world population. Social movements and non-governmental organizations have readily integrated the concept into their terminology. The concept is also beginning to find its way into the debates and policies of UN organizations and national governments in both developing and industrialized countries. Beyond its relation to civil society movements little academic attention has been paid to the concept of food sovereignty and its appropriateness for international development policies aimed at reducing hunger and poverty, especially in comparison to the human right to adequate food (RtAF). We analyze, on the basis of an extensive literature review, the concept of food sovereignty with regard to its ability to contribute to hunger and poverty reduction worldwide as well as the challenges attached to this concept. Then, we compare the concept of food sovereignty with the RtAF and discuss the appropriateness of both concepts for national public sector policy makers and international development policies. We conclude that the impact on global food security is likely to be much greater if the RtAF approach predominated public policies. While the concept of food sovereignty may be appropriate for civil society movements, we recommend that the RtAF should obtain highest priority in national and international agricultural, trade and development policies.  相似文献   

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Economic opportunities and the status of women are mediated by socio-political structural factors, as well as cultural-specific norms and patterns of behavior. As consumers (and, in many cases, regulators) of resources at the household level, women are integral to the analysis of economic and political development. This paper examines the role of motivation and perception on women’s participation in Palestinian Fair Trade projects. In the occupied Palestinian Territories, Fair Trade projects have been recently introduced by both international agencies and local Palestinian associations as means through which women can earn income, participate in cooperative leadership, and engage at economic and political levels. Current scholarship largely focuses on measuring outcomes of Fair Trade initiatives or the experiences of members after the implementation of a project. However, there is less understanding about factors influencing the recruitment and retention of members into these initiatives. This ethnographic account explores both the motivations of members to join several couscous (maftoul) Fair Trade cooperatives and the members’ understanding Fair Trade goals and the cooperative structure. We examine four Palestinian women’s maftoul cooperatives and their unique challenges and opportunities. This project highlights the lack of detail most women have about the global Fair Trade market, which has a potential to result in decreased recruitment and retention rates. This paper also examines the tensions between product quality and market demands existing within couscous cooperatives and the competing demands of child-care needs, household pressures, and military restrictions on Palestinian movement enforced by the Israeli military within the occupied Palestinian Territories.  相似文献   

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Winter jujube orchard nitrogen (N) management aims at increasing N reserves to meet the tree's growth requirements. Fertilization strategies should maximize the efficiency of fertilizers, including the choice of the optimal timing of N supply. ^15N-urea was applied to winter jujubes on Jinsixiaozao jujubes rootstock to evaluate the effect of application timing on Nstorage and remobilization in mature trees in pot culture. The treatments consisted of ground application before budding (BB), during fruit core-hardening stage (FCH), and fruit rapid-swelling stage (FRS). Nitrogen-use efficiency of treatments were significantly different, which were 2.42% (BB), 9.77% (FCH), and 9.01% (FRS) in the dormant and 5.20% (BB), 16.16% (FCH), and 10.30% (FRS) in the following full-bloom. N supply in the pre-harvest helped to increase N-reserves of trees and then translocate to the new growth organs the following year. The largest amount of ^15N was detected in the roots and trunks. In all the treatments, the partition rates were highest in coarse roots, which were 30.43% (BB), 38.61% (FCH), and 40.62% (FRS), respectively. ^15N stored in roots and trunks was used by jujube trees to sustain new growth in the following full-bloom. ^15N applied before budding resulted in lower Ndff% in perennial organs (trunks and coarse roots) sampled in the following full-bloom, but fine roots had highest Ndff% (1.28%). Other organs recovered similar amount of Ndff%. In contrast, FCH and FRS treatments led to higher Ndff% (4.01-5.15%) in the new growth organs (new growth branches, deciduous spurs, leaves and flowers), but lower Ndff% in perennial branches (1.49-2.89%). With the delay of ^15N-urea application time, ^15N increased the partitioning to roots. FCH treatment increased N-storage in perennial organ during winter, which should be remobilized to sustain new growth the following spring.  相似文献   

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Linseed (Linum usitatissimum L.) is an important dual-purpose, industrial crop. Its seeds are used for the extraction of oil and stem for fibres. However, the production of linseed is not going parallel with the increasing demand of its products. The present work was carried out with an aim to find out whether exogenous application of gibberellic acid (GA3) with or without graded levels of nitrogen (N) and phosphorus (P) could improve the performance of three linseed genotypes Parvati, Shekhar and Shubhra together with minimizing the costly fertilizer input and losses. Four combinations of N and P, viz., 0 mg N+0 mg P kg-1 soil (N0P0), N13.4 P4.46 , N26.8P8.94 and N40.2P13.4 were constituted. Half dose of each combination was applied basally at the time of sowing and remaining half dose was given at 40 d after sowing (DAS) as foliar spray along with 10-6 mol L-1 GA3 . Prior to sowing, the seeds of each linseed genotype were grouped in to two, one group of seeds was soaked in 0 mol L-1 GA3 (control) and the other group was soaked in 10-6 M GA3 solution, each for 8 hours. Treatments were comprised of (i) 0 mol L-1 GA3+N0P0 (T0 , control), (ii) 10-6 mol L-1 GA3 + N13.4P4.46 (T1), (iii) 10-6 mol L-1 GA 3 +N 26.8 P 8.94 (T2) and (iv) 10-6 mol L-1 GA3+N40.2P13.4 (T3). The crop performance was assessed in terms of growth, physiological and biochemical parameters at 60 and 75 DAS and yield attributes at harvest (175 DAS). The results showed a parallel increase in most of the parameters with increasing levels of N and P. However, application of 10-6 mol L-1 GA3 in association with N26.8P8.94 proved best, it enhanced seed yield, oil yield and fibre yield by 83.3, 97.3 and 78.7%, respectively accompanied with increase in net photosynthetic rate, carbonic anhydrase activity and dry matter accumulation. Among the genotypes tested, Shubhra performed best, while Parvati the least for most of the parameters studied. Thus, combined application of 10-6 mol L-1 GA3 plus N26.8P8.94 proved best and can be recommended to exploit the linseed as a dual-purpose crop for good yield of seed and fibre.  相似文献   

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研究烹饪对常见的几种禽蛋蛋黄中类胡萝卜素的影响。利用分光光度法测定烹饪前后鸡蛋、鸭蛋和鹌鹑蛋蛋黄中的总类胡萝卜素含量,利用HPLC法分离并测定烹饪前后鸡蛋、鸭蛋和鹌鹑蛋蛋黄中的各类胡萝卜素组分的含量。测定出了鸡蛋、鸭蛋和鹌鹑蛋的鲜蛋和熟蛋中总类胡萝卜素及其各组分的含量。(1)鸭蛋和鹌鹑蛋蛋黄中含叶黄素、玉米黄素、角黄素、隐黄素和β-胡萝卜素,鸡蛋蛋黄中除上述组分外还含有辣椒红素;(2)烹饪前后蛋黄中类胡萝卜素组分的种类和各组分含量的排序无变化;(3)在煮熟的过程中,蛋黄中各类胡萝卜素组分的平均损失率分别为鸡蛋9.3%~19.0%,鸭蛋8.8%~23.0%,鹌鹑蛋18.4%~34.7%。  相似文献   

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