Size Dependence of Structural Metastability in Semiconductor Nanocrystals     

CC Chen  AB Herhold  CS Johnson  AP Alivisatos 《Science (New York, N.Y.)》1997,276(5311):398-401

The kinetics of a first-order, solid-solid phase transition were investigated in the prototypical nanocrystal system CdSe as a function of crystallite size. In contrast to extended solids, nanocrystals convert from one structure to another by single nucleation events, and the transformations obey simple unimolecular kinetics. Barrier heights were observed to increase with increasing nanocrystal size, although they also depend on the nature of the nanocrystal surface. These results are analogous to magnetic phase transitions in nanocrystals and suggest general rules that may be of use in the discovery of new metastable phases.  相似文献   

Measurement of Parity Nonconservation and an Anapole Moment in Cesium     

CS Wood  SC Bennett  D Cho  BP Masterson  JL Roberts  CE Tanner  CE Wieman 《Science (New York, N.Y.)》1997,275(5307):1759-1763

The amplitude of the parity-nonconserving transition between the 6S and 7S states of cesium was precisely measured with the use of a spin-polarized atomic beam. This measurement gives Im(E1pnc)/beta = -1.5935(56) millivolts per centimeter and provides an improved test of the standard model at low energy, including a value for the S parameter of -1.3(3)exp (11)theory. The nuclear spin-dependent contribution was 0.077(11) millivolts per centimeter; this contribution is a manifestation of parity violation in atomic nuclei and is a measurement of the long-sought anapole moment.  相似文献   

Synthesis and testing of novel alternative oxidase (AOX) inhibitors with antifungal activity against Moniliophthora perniciosa (Stahel), the causal agent of witches' broom disease of cocoa,and other phytopathogens     

Mario RO Barsottini  Brbara A Pires  Maria L Vieira  Jos GC Pereira  Paulo CS Costa  Jaqueline Sanit  Alessandro Coradini  Fellipe Mello  Cidnei Marschalk  Eder M Silva  Daniele Paschoal  Antonio Figueira  Fbio HS Rodrigues  Artur T Cordeiro  Paulo CML Miranda  Paulo SL Oliveira  Maurício L Sfora  Marcelo F Carazzolle  Silvana A Rocco  Gonalo AG Pereira 《Pest management science》2019,75(5):1295-1303

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Preliminary investigation into the prevalence of mucormycosis in the platypus (Ornithorhynchus anatinus) in three catchments in north-west Tasmania     

JW Macgregor  CS Holyoake  SA Munks  ID Robertson  KS Warren 《Australian veterinary journal》2010,88(5):190-196

Objective To investigate the distribution and prevalence of mucormycosis in platypus (Ornithorhynchus anatinus) from the Inglis, Emu and Black-Detention catchment areas in north-west Tasmania. Procedure A field study was performed and resulted in the examination of 44 wild platypuses; in addition, one dead platypus and two live platypuses were examined after they were independently submitted to a local veterinary clinic. Results No cases of mucormycosis were conclusively diagnosed. One platypus with signs consistent with those previously described in cases of mucormycosis was captured in the Emu River catchment. However, laboratory tests did not provide a definitive diagnosis for the lesion. Two platypuses from the Inglis catchment area had signs very similar to those previously described in cases of mucormycosis, but laboratory tests found Corynebacterium ulcerans to be the likely cause of the cutaneous ulcers on one of these platypuses and an unidentified fungal agent to be the cause of a cutaneous nodule in the other. Conclusions These findings do not prove that mucormycosis is absent from the populations studied. However, they may indicate that the prevalence of disease is low. The possibility that Mucor amphibiorum is present in a subclinical form in platypuses, or infecting another reservoir, is not excluded. The findings also suggest that caution should be exercised when diagnosing mucormycosis based on clinical findings alone and raise the possibility that some cases may have been incorrectly diagnosed.  相似文献   

Estimating the development of the fennel aphid,Hyadaphis foeniculi (Passerini) (Hemiptera: Aphiididae), using non‐linear models          下载免费PDF全文

José B Malaquias  Francisco S Ramalho  Aline CS Lira  Flávia Q Oliveira  Francisco S Fernandes  José C Zanuncio  Wesley AC Godoy 《Pest management science》2015,71(5):744-751

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Cricopharyngeal dysphagia and phenobarbitone‐responsive sialoadenosis in a Miniature Poodle          下载免费PDF全文

SAM McCann  M le Chevoir  L Lacorcia  BGJ Wernham  CS Mansfield 《Australian veterinary journal》2017,95(7):232-236

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匈牙利半湿润气候地区田间尺度下土壤侵蚀引起的土壤有机碳再分布     

Z. SZALAI  J. SZAB&#;  J. KOV&#;CS  E. M&#;SZ&#;ROS  G. ALBERT  C. CENTER  B. SZAB&#;  B. MADAR&#;SZ  D. ZACH&#;RY  G. JAKAB 《土壤圈》2016,26(5):652-665

Soil organic carbon(SOC) has primary importance in terms of soil physics, soil fertility and even of climate change control. One hundred soil samples were taken from an intensively cultivated Cambisol to quantify SOC redistribution triggered by soil erosion under a subhumid climate, by the simultaneous application of diffuse reflectance(240–1 900 nm) and traditional physico-chemical methods.The representative sample points were collected from the solum along the slopes at the depth of 20–300 cm with a mean SOC content of 12 g kg~(-1). Hierarchical cluster analyses were performed based on the determined SOC results. The spatial pattern of the groups created were similar, and even though the classifications were not the same, diffuse reflectance had proven to be a suitable method for soil/sediment classification even within a given arable field. Both organic and inorganic carbon distributions were found to be a proper tool for estimations of past soil erosion processes. The SOC enrichment was found on two sedimentary spots with different geomorphological positions. Soil organic matter composition also differed between the two spots due to selective deposition of the delivered organic matter. The components with low-molecular-weight reached the bottom of the slope where they could leach into the profile, while the more polymerised organic matter compositions were delivered and deposited even before on a higher segment of the slope in an aggregated form. This spatial difference appeared below the uppermost tilled soil layer as well, referring the lower efficiency of conventional ploughing tillage in soil spatial homogenisation.  相似文献   

Evidence of Damage in Cryopreserved and Fresh Bovine Embryos Using the Tunel Technique   总被引：1，自引：0，他引：1  

YC Márquez-Alvarado  CS Galina  B Castilla  H León  N Moreno-Mendoza 《Reproduction in domestic animals》2004,39(3):141-145

The objective of the present study was to evaluate the quality of bovine embryos cryopreserved in different years in Chiapas, Mexico. The embryos were obtained from a government institution (FIMEGEN) dedicated to promoting embryo transfer among dual-purpose cattle farmers. Forty-three embryos frozen in 1988, 1989, 2000 and 2002 were analysed with the Tunel technique to detect programmed cell death (apoptosis). Eleven fresh embryos were used as controls. Analysis of variance was used in embryos stored in the different years with averages tested using Tukey's test. Student's t-test was employed to compare fresh and frozen cells. Embryos with shorter storage time presented a lower number (p < 0.001) of Tunel-positive cells compared with embryos stored for longer time. On the contrary, when comparing the number of apoptotic cells between frozen and fresh embryos a higher number of positive cells (p < 0.05) were found in the former. The present results suggest that the cryopreservation per se caused damage that compromises the viability of the embryo. Another explanation for the lower pregnancy rate found in the tropics could be irreversible damage caused by poor storage technique in these large operations.  相似文献   

Rapid differentiation of Mycobacterium bovis and Mycobacterium tuberculosis based on a 12.7-kb fragment by a single tube multiplex-PCR     

Bakshi CS  Shah DH  Verma R  Singh RK  Malik M 《Veterinary microbiology》2005,109(3-4):211-216

The aim of this work was the design and validation of a rapid and easy single tube multiplex-PCR (m-PCR) assay for the unequivocal differential detection of Mycobacterium bovis and Mycobacterium tuberculosis. Oligonucleotide primers were based on the uninterrupted 229-bp sequence in the M. bovis genome and a unique 12.7-kb insertion sequence from the M. tuberculosis genome, which is responsible for species-specific genomic polymorphism between these two closely related pathogens. The m-PCR assay was optimized and validated using 22 M. bovis and 36 M. tuberculosis clinical strains isolated from diverse host species and 9 other non-tuberculous mycobacterial (NTM) strains. The designed primers invariably amplified a unique 168-bp (M. bovis-specific) and 337-bp (M. tuberculosis-specific) amplicon from M. bovis and M. tuberculosis strains, respectively. The accuracy of the assay, in terms of specificity, was 100%, as none of the NTM strains tested revealed any amplification product. As little as 20 pg of genomic DNA could be detected, justifying the sensitivity of the method. The m-PCR assay is an extremely useful, simple, reliable and rapid method for routine differential identification of cultures of M. bovis and M. tuberculosis. This m-PCR may be a valuable diagnostic tool in areas of endemicity, where bovine and human tuberculosis coexist, and the distinction of M. bovis from M. tuberculosis is required for monitoring the spread of M. bovis to humans.  相似文献   

Detection of Rinderpest Virus Using N-Protein Monoclonal Antibodies     

Shah RA  Joseph MC  Butchaiah G  Malik M  Singh RK  Bakshi CS 《Tropical animal health and production》2004,36(1):11-25

A panel of monoclonal antibodies (mAbs) was generated against the RBOK strain of rinderpest virus (RPV). All of them bound to the N protein of RPV. The antigen capture ELISA using the mAbs could detect the virus in crude viral preparations. The mAb 12BF8.1.1 showed higher reactivity with cell-associated (CA) virus, whereas the mAbs 12AD10.1.1, 12BD7.1.1 and 12DG7.1.1 showed higher reactivity with extracellular virus (hereafter referred to as cell-free (CF) virus). The mAbs 12BF8.1.1 and 12AD10.1.1 could detect the virus in infected Vero cell culture supernatants (CCS) as early as 24 h post-cytopathic effect (CPE) initiation. Detergent treatment (Triton X-100) of RPV preparations enhanced the binding of the mAbs to the virus. All the seven mAbs showed specific fluorescence in virus-infected cell cultures. The immunofluorescence (IFA) using mAbs was found to be more sensitive and reliable than the immunoperoxidase test (IPT) for detection of rinderpest.  相似文献