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1.
Effect of Oil Overlay on Inhibition Potential of Roscovitine in Sheep Cumulus‐Oocyte Complexes 
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下载免费PDF全文 LF Crocomo WC Marques Filho CMV Ulian NS Branchini DT Silva CL Ackermann FC Landim‐Alvarenga SD Bicudo 《Reproduction in domestic animals》2015,50(3):410-416
Inhibitors of cyclin‐dependent kinases, as roscovitine, have been used to prevent the spontaneous resumption of meiosis in vitro and to improve the oocyte developmental competence. In this study, the interference of oil overlay on the reversible arrest capacity of roscovitine in sheep oocytes as well as its effects on cumulus expansion was evaluated. For this, cumulus‐oocyte complexes (COCs) were cultured for 20 h in TCM 199 with 10% foetal bovine serum (Control) containing 75 μm roscovitine (Rosco). Subsequently, they were in vitro matured (IVM) for further 18 h in inhibitor‐free medium with LH and FSH. The culture was performed in Petri dishes under mineral oil (+) or in 96 well plates without oil overlay (?) at 38.5°C and 5% CO2. At 20 and 38 h, the cumulus expansion and nuclear maturation were evaluated under stereomicroscope and by Hoechst 33342 staining, respectively. No group presented cumulus expansion at 20 h. After additional culture with gonadotrophins, a significant rate of COCs from both Control groups (+/?) exhibited total expansion while in both Rosco groups (+/?) the partial expansion prevailed. Among the oocytes treated with roscovitine, 65.2% were kept at GV in the absence of oil overlay while 40.6% of them reached MII under oil cover (p < 0.05). This meiotic arrest was reversible, and proper meiosis progression also occurred in the Control groups (+/?). So, the culture system without oil overlay improved the meiotic inhibition promoted by roscovitine without affecting the cumulus expansion rate or the subsequent meiosis progression. 相似文献
2.
Malm O Guimarães JRD Castro MB Bastos WR Viana JP Branches FJP Silveira EG Pfeiffer WC 《Water, air, and soil pollution》1997,97(1-2):45-51
Informal economy of gold mining has contaminated some important river basins in Amazon. Follow-up studies on critical compartments showed some areas with high Hg levels in fish as well as in human hair samples. Average Hg in piscivorous fish in the Madeira river itself was 846 ppb (N=284) with a maximum of 3921 ppb. Mercury in fish from non polluted areas in this basin shows high variability, even for single species. A seasonal variation in Hg content was observed, with higher values at the end of the dry season. In the upper Tapajós basin comparable values were found for fish but with a definite decreasing trend downstream. Average value for piscivorous fish in the whole Tapajós basin is 482 ppb (N=122) with a maximum value of 3770 ppb. Hair Hg was higher in fishing villages in the Tapajós (average: 17 ppm; with N=432 and maximum value of 176 ppm) than in the Madeira (average: 9 ppm; N=169; maximum 71 ppm), and data from some areas of the Tapajós suggest a decrease with time. Mercury was much higher in urine of goldshop workers in Santarém (low Tapajós) than in Alta Floresta (high Tapajbs) and show a decreasing trend in both cases, probably related to the significant decline in gold mining activities during the study period (1986–1994). 相似文献
3.
Kamada N Kim YG Sham HP Vallance BA Puente JL Martens EC Núñez G 《Science (New York, N.Y.)》2012,336(6086):1325-1329
The virulence mechanisms that allow pathogens to colonize the intestine remain unclear. Here, we show that germ-free animals are unable to eradicate Citrobacter rodentium, a model for human infections with attaching and effacing bacteria. Early in infection, virulence genes were expressed and required for pathogen growth in conventionally raised mice but not germ-free mice. Virulence gene expression was down-regulated during the late phase of infection, which led to relocation of the pathogen to the intestinal lumen where it was outcompeted by commensals. The ability of commensals to outcompete C. rodentium was determined, at least in part, by the capacity of the pathogen and commensals to grow on structurally similar carbohydrates. Thus, pathogen colonization is controlled by bacterial virulence and through competition with metabolically related commensals. 相似文献
4.
WC Feldman BL Barraclough S Maurice RC Elphic DJ Lawrence DR Thomsen AB Binder 《Science (New York, N.Y.)》1998,281(5382):1489-1493
Global maps of thermal and fast neutron fluxes from the moon suggest three end-member compositional units. A high thermal and low fast neutron flux unit correlates with the lunar highlands and is consistent with feldspathic rocks. The South Pole-Aitken basin and a strip that surrounds the nearside maria have intermediate thermal and fast neutron flux levels, consistent with more mafic rocks. There appears to be a smooth transition between the most mafic and feldspathic compositions, which correspond to low and high surface altitudes, respectively. The maria show low thermal and high fast neutron fluxes, consistent with basaltic rocks. 相似文献
5.
RC Elphic DJ Lawrence WC Feldman BL Barraclough S Maurice AB Binder PG Lucey 《Science (New York, N.Y.)》1998,281(5382):1493-1496
The Lunar Prospector neutron spectrometer data correlate well with iron and titanium abundances obtained through analysis of Clementine spectral reflectance data. With the iron and titanium dependence removed, the neutron spectrometer data also reveal regions with enhanced amounts of gadolinium and samarium, incompatible rare earth elements that are enriched in the final phases of magma crystallization. These regions are found mainly around the ramparts of the Imbrium impact basin but not around the other basins, including the much larger and deeper South Pole-Aitken basin. This result confirms the compositional uniqueness of the surface and interior of the Imbrium region. 相似文献
6.
Murali Haran K. Sham Bhat Julio Molineros Erick De Wolf 《Journal of Agricultural, Biological & Environmental Statistics》2010,15(2):158-175
Fusarium Head Blight (FHB), or “scab,” is a very destructive disease that affects wheat crops. Recent research has resulted
in accurate weather-driven models that estimate the probability of an FHB epidemic based on experiments. However, these predictions
ignore two crucial aspects of FHB epidemics: (1) An epidemic is very unlikely to occur unless the plants are flowering, and
(2) FHB spreads by its spores, resulting in spatial and temporal dependence in risk. We develop a new approach that combines
existing weather-based probabilities with information on flowering dates from survey data, while simultaneously accounting
for spatial and temporal dependence. Our model combines two space-time processes, one associated with pure weather-based FHB
risks and the other associated with flowering date probabilities. To allow for scalability, we model spatiotemporal dependence
via a process convolutions approach. Our sample-based approach produces a realistic assessment of areas that are persistently
at high risk (where the probability of an epidemic is elevated for extended time periods), along with associated estimates
of uncertainty. We conclude with the application of our approach to a case study from North Dakota. 相似文献
7.
Organogenesis and foetal haemodynamics during the normal gestation of healthy black‐rumped agoutis (Dasyprocta prymnolopha,Wagler, 1831) bred in captivity 下载免费PDF全文
下载免费PDF全文 FCA Sousa GT Pessoa LS Moura JR Araújo RPS Rodrigues MAPS Barbosa AN Diniz AB Souza EG Silva LU Lucena MP Sanches OF Silva‐Filho PC Guerra JM Sousa WC Neves FR Alves 《Reproduction in domestic animals》2017,52(1):60-66
The objective of this study was to define the patterns of organogenesis and foetal haemodynamics during the normal gestation of healthy agoutis (Dasyprocta prymnolopha) kept in captivity. Thirty pregnant agoutis that ranged in size from small to medium and weighed between 2.5 and 3 kg underwent B‐mode and Doppler ultrasonography for the biometric evaluation of the foetal organs. The foetal aortic blood flow proved to be predominantly systolic, and the measured flow velocity was 78.89 ± 2.95 cm/s, with a maximum pressure gradient of 2.12 ± 0.27 mmHg. The liver was characterized by its large volume, occupying the entire cranial aspect of the abdominal cavity, and it was associated cranially with the diaphragm and caudally with the stomach. The flow velocity in the portal vein was estimated to equal 12.17 ± 2.37 cm/s, with a resistivity index of 0.82 ± 0.05. The gallbladder was centrally located and protruded cranially towards the diaphragm. The spleen was visualized as an elongated structure with tapered cranial and caudal extremities, and the foetal kidneys were visualized bilaterally in the retroperitoneal region, with the right kidney positioned slightly more cranially than the left. The morphological characterization and hemodynamic analysis of the foetal organs of black‐rumped agoutis via B‐mode and Doppler ultrasonography allow determination of the vascular network and of reference values for the blood flow required for perfusing the anatomical elements essential for maintaining the viability of foetuses at different gestational ages. 相似文献
8.
Ha WY Reid DG Kam WL Lau YY Sham WC Tam SY Sin DW Mok CS 《Journal of agricultural and food chemistry》2011,59(10):5195-5203
Abalones ( Haliotis species) are a popular delicacy and commonly preserved in dried form either whole or in slices or small pieces for consumption in Asian countries. Driven by the huge profit from trading abalones, dishonest traders may substitute other molluscan species for processed abalone, of which the morphological characteristics are frequently lost in the processed form. For protection of consumer rights and law enforcement against fraud, there is a need for an effective methodology to differentiate between fake and genuine abalone. This paper describes a method (validated according to the international forensic guidelines provided by SWGDAM) for the identification of fake abalone species using forensically informative nucleotide sequence (FINS) analysis. A study of the local market revealed that many claimed "abalone slice" samples on sale are not genuine. The fake abalone samples were found to be either volutids of the genus Cymbium (93%) or the muricid Concholepas concholepas (7%). This is the first report of Cymbium species being used for the preparation and sale as "abalone" in dried sliced form in Hong Kong. 相似文献
9.
Chen G Bonadeo NH Steel DG Gammon D Katzer DS Park D Sham LJ 《Science (New York, N.Y.)》2000,289(5486):1906-1909
Optically induced entanglement is identified by the spectrum of the phase-sensitive homodyne-detected coherent nonlinear optical response in a single gallium arsenide quantum dot. The electron-hole entanglement involves two magneto-excitonic states differing in transition energy and polarization. The strong coupling needed for entanglement is provided through the Coulomb interaction involving the electrons and holes. The result presents a first step toward the optical realization of quantum logic operations using two or more quantum dots. 相似文献
10.
Li X Wu Y Steel D Gammon D Stievater TH Katzer DS Park D Piermarocchi C Sham LJ 《Science (New York, N.Y.)》2003,301(5634):809-811
We report coherent optical control of a biexciton (two electron-hole pairs), confined in a single quantum dot, that shows coherent oscillations similar to the excited-state Rabi flopping in an isolated atom. The pulse control of the biexciton dynamics, combined with previously demonstrated control of the single-exciton Rabi rotation, serves as the physical basis for a two-bit conditional quantum logic gate. The truth table of the gate shows the features of an all-optical quantum gate with interacting yet distinguishable excitons as qubits. Evaluation of the fidelity yields a value of 0.7 for the gate operation. Such experimental capability is essential to a scheme for scalable quantum computation by means of the optical control of spin qubits in dots. 相似文献