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Apoptosis and DNA damage in human spermatozoa

Asian journal of Andrology 2011年第1期13卷 36-42页

作者： r john Aitken Adam j Koppers ArC Centre of Excellence in Biotechnology and Development Priority Research Centre in Reproductive Science Discipline of Biological Sciences School of Environmental and Life Sciences University of Newcastle Callaghan NSW 2308 Australia Department of Anatomy and Developmental Biology School of Biomedical Sciences Monash University Clayton VIC 3800 Australia

DNA damage is frequently encountered in spermatozoa of subfertile males and is correlated with a range of adverse clinical outcomes including impaired fertilization, disrupted preimplantation embryonic development, increased rates of miscarriage and an enhanced risk of disease in the progeny. The etiology of DNA fragmentation in human spermatozoa is closely correlated with the appearance of oxidative base adducts and evidence of impaired spermiogenesis. We hypothesize that oxidative stress impedes spermiogenesis, resulting in the generation of spermatozoa with poorly remodelled chromatin. These defective cells have a tendency to default to an apeptotic pathway associated with motility loss, caspase activation, phosphatidylserine exteriorization and the activation of free radical generation by the mitochondria. The latter induces lipid peroxidation and oxidative DNA damage, which then leads to DNA fragmentation and cell death. The physical architecture of spermatozoa prevents any nucleases activated as a result of this apoptotic process from gaining access to the nuclear DNA and inducing its fragmentation. It is for this reason that a majority of the DNA damage encountered in human spermatozoa seems to be oxidative. Given the important role that oxidative stress seems to have in the etiology of DNA damage, there should be an important role for antioxidants in the treatment of this condition. If oxidative DNA damage in spermatozoa is providing a sensitive readout of systemic oxidative stress, the implications of these findings could stretch beyond our immediate goal of trying to minimize DNA damage in spermatozoa as a prelude to assisted conception therapy.

关键词： apoptosis DNA damage oxidative stress spermatozoa

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Dependency-aware unequal erasure protection codes

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journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第Z1期7卷 27-33页

作者： BOUABDALLAH Amine LACAN jérme Laboratory for Analysis and Architecture of Systems Toulouse 31077 France Applied Mathematics and Computer Science DepartmentENSICAToulouse 31056France Telecommunications for Space and AeronauticToulouse 31000France

Classical unequal erasure protection schemes split data to be protected into classes which are encoded independently. The unequal protection scheme presented in this paper is based on an erasure code which encodes all the data together according to the existing dependencies. A simple algorithm generates dynamically the generator matrix of the erasure code according to the packets streams structure, i.e., the dependencies between the packets, and the rate of the code. This proposed erasure code was applied to a packetized MPEG4 stream transmitted over a packet erasure channel and compared with other classical protection schemes in terms of PSNr and MOS. It is shown that the proposed code allows keeping a high video quality-level in a larger packet loss rate range than the other protection schemes.

关键词： Data dependencies integration Unequal erasure protection (UEP) Lossy networks reliable video transmissions MPEG4 video codec

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OSCILLATION AND VArIATION OF THE LAGUErrE HEAT AND POISSON SEMIGrOUPS AND rIESZ TrANSFOrMS

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Acta Mathematica Scientia 2012年第3期32卷 907-928页

作者： j.j.Betancor r.Crescimbeni j.L.Torrea Departamento de An'aisis Matema'ico Universidad de La Laguna38271-La LagunaTenerifeIslas CanariasSpain Departamento de Matema'ica Universidad Nacional del ComahueBuenos Aires 14008300 Neuqu'enArgentina Departamento de Matem'aticas Facultad de CienciasUniversidad Auto'noma de Madrid28049 MadridSpain

In this article, we study LP-boundedness properties of the oscillation and vari- ation operators for the heat and Poissson semigroup and riesz transforms in the Laguerre settings. Also, we characterize Hardy spaces as... 详细信息

关键词： Oscillation variation heat Laguerre semigroup riesz transforms

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Simplicial Indicator Kriging

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journal of China University of Geosciences 2008年第1期19卷 65-71页

作者： r Tolosana-Delgado V Pawlowsky-Glahn j j Egozcue Department of Sedimentology and Environmental Geology Georg-August-Universitt Gttingen D-37077 Gttingen Germany Department of Computer Science and Applied Mathematics University of Girona Girona Spain Department of Applied Mathematics III Universidad Politécnica de Catalunya Barcelona Spain

Indicator kriging （IK） is a spatial interpolation technique devised for estimating a conditional cumulative distribution function at an unsampled location. The result is a discrete approximation, and its corresponding estimated probability density function can be viewed as a composition in the simplex. This fact suggested a compositional approach to IK which, by construction, avoids all its standard drawbacks （negative predictions, not-ordered or larger than one）. Here, a simple algorithm to develop the procedure is presented.

关键词： Aitchison geometry compositional data disjunctive kriging log-ratio approach simplex.

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Soil Environmental Index For Slovak Agricultural Land

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Pedosphere 2014年第1期24卷 137-144页

作者： j.VILCEK r.BUjNOVSKY Department of Geography and regional Development Faculty of Humanities and Natural SciencesUniversity of Presov Soil Science and Conservation research Institute

The soil environmental index(SEI),which is a four digit code system,represents relatively homogenous spatial unit with specific soil capacity to provide ecological or non-production *** work aimed to present information on rating and economic evaluation of SEI,which is a spatial identifier used for expressing heterogeneity of Slovak agricultural soil to support analysis of soil ecological *** this study,SEI index expressed the capacity of soil to accumulate water,immobilise the risk elements and substances and transform risk substances(organic pollutants).Partial evaluations of soil capacity to provide above mentioned functions were used to derive final SEI *** the agricultural soils of Slovakia there were 493 combinations of soil environmental *** index was expressed through rating(point)value and economic *** value of Slovak agricultural land to provide selected ecological soil functions was 55.3 points,which corresponded to 35.946 billionper agricultural land or approximately 1.42per square *** identification of SEI codes and relevant database were developed in vector form via geographical information systems of Soil Science and Conservation research Institute,*** addition to using the national soil database system,a strategy was presented for evaluating and pricing of soil ecological function,and the development of an soil environmental *** and evaluation of vitally important soil functions expressed by SEI can significantly contribute to planning and protection of the soil,and can regulate indiscriminate anthropic interventions in land use decisions.

关键词： ecological soil functions environmental potential soil evaluation

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rapid climate change-induced collapse of hunter-gatherer societies in the lower Mississippi river valley between ca. 3300 and 2780 cal yr BP

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Science China Earth Sciences 2018年第2期61卷 178-189页

作者： tristram r.kidder edward r.henry lee j.arco Department of Anthropology Washington University in St. Louis St. Louis 63130 USA Geoarehaeology Laboratory Washington University in St. Louis St. Louis 63130 USA GAI Consultants Inc. Homestead PA 15120 USA Teaching and Experimental Center for Archaeology and Cultural Heritage Protection Henan University Kaifeng 475001 China

Hunter-gatherer communities in the American Southeast reached an apogee of social and political complexity in the period between ca. 4200 and 3000 cal yr BP. In the lower Mississippi Valley(LMV) the Poverty Point culture defined this period of socio-political elaboration. However, following a significant period of climate change that led to exceptional flooding and a major reorganization of the course of the Mississippi river, this culture collapsed beginning ca. 3300–3200 cal yr BP and the LMV was abandoned for the subsequent 500 years. In this study, we use data from the jaketown site in the Yazoo Basin of west-central Mississippi to refine the chronology of the climate event that caused the collapse of the Poverty Point culture. A large flood buried Poverty Point-era occupation deposits at jaketown around 3310 cal yr BP. Lateral migration of the Mississippi river during flooding led to inundation of the Yazoo Basin and re-occupation of ancient river courses. A coarse sand stratum topped by a more than a meter-thick fining upward sediment package marks a crevasse deposit caused by a rupture of the natural levee at jaketown. This levee breach was part of a larger pattern of erratic flooding throughout the LMV and is associated with major landscape evolution and the abandonment of Poverty Point sites within the valley. Early Woodland peoples re-colonized the crevasse surface after ca. 2780 cal yr BP. Following this event, the jaketown site and the eastern Yazoo Basin witnessed a period of landscape stability that lasts to this day. These archaeological data demonstrate how climate change and natural disasters can lead to socio-political dissolution and reorganization even in relatively small-scale hunter-gatherer populations.

关键词： rapid climate change Hunter-gatherers Flooding Mississippi river Valley Poverty Point jaketown site

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Effect of papaya seed extract on microenvironment of cauda epididymis

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Asian journal of Andrology 2001年第2期3卷 143-146页

作者： r.j.Verma N.j.Chinoy Department of Zoology University School of Sciences Gujarat University Ahmedabad 380009 IndiaDepartment of Zoology University School of Sciences Gujarat University Ahmedabad 380009 India

Aim: To evaluate the effect of aqueous Carica papaya seed extract on microenvironment of cauda ***: Adult male albino rats were intramuscularly administered with 0 (control) or 0.5 mg papaya seed ex-tract/kg body weight for 7 days. Cauda epididymal tubular content was collected by micropuncture technique; epididy-mal luminal fluid and sperm pellets were separately analyzed. results: The results revealed that the extract treat-ment caused significant reduction, as compared with control, in total protein and sialic acid contents in both epididymalfluid and sperm pellet. As compared with control, significantly lowered acid phosphatase activity was recorded in spermpellet but was higher in epididymal fluid after the treatment. The extract treatment also caused significant reduction inlevel of inorganic phosphorus in the epididymal fluid. Conclusion: It is concluded that the aqueous papaya seed ex-tract alters cauda epididymal microenvironment.

关键词： Carica papaya microenvironment epididymis spermatozoa protein sialic acid

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Anisotropy of rare-earth magnets

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journal of rare Earths 2009年第4期27卷 675-679页

作者： r.Skomski D.j.Sellmyer Department of Physics and Astronomy NCMN University of Nebraska

rare-earth intermetallics such as Nd2Fe14B and Sm-Co are widely used as high-performance permanent magnets, because they combine high magnetocrystalline anisotropy with reasonable magnetization and Curie temperature. The anisotropy is a combined effect of spin-orbit coupling and electrostatic crystal-field interactions. The main contribution comes from the rare-earth 4f electrons, which are well-screened from the crystalline environment but exhibit a strong spin-orbit coupling. In this limit, the magnetocrystalline anisotropy has a very transparent physical interpretation, the anisotropy energy essentially being equal to the energy of Hund＇s-rules 4f ion in the crystal field. The corresponding expression for the lowest-order uniaxial anisotropy constant K1 is used to discuss rare-earth substitutions, which have recently attracted renewed interest due to shifts in the rare-earth production and demand. Specific phenomena reviewed in this article are the enhancement of the anisotropy of Sm2Fe17 due to interstitial nitrogen, the use of Sm-Co magnets for high-temperature applications, and the comparison of rare-earth single-ion anisotropy with other single-ion and two-ion mechanisms.

关键词： magnetic anisotropy spin-orbit coupling crystal-field interaction interstitial modification permanent magnets rare earths

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Influence of the wakes of rotating spokes on the performance of a turbine exhaust diffuser

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journal of Thermal Science 2010年第3期19卷 206-210页

作者： M.Kuschel j.r.Seume Institute of Turbomachinery and Fluid Dynamics Leibniz University HannoverD-30167 HannoverGermany

The design of turbine exhaust diffusers is still commonly based upon conservative design charts which do not consider the influence of the components installed upstream such as the last turbine *** on investigations with different spoke wheels which approximate the blade wakes of the last turbine stage,the influence of a rotating bladed disc on the flow in a exhaust diffuser is *** pressure recovery for an annual diffuser with 15° half cone angle and the 5 mm spoke wheel used in the model test is very high and nearly independent on the rotational speed and the corresponding Strouhal *** a 20° annual diffuser,the pressure recovery increases with Strouhal number

关键词： turbine exhaust diffuser rotating wakes separation

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Moduli of Polarized Calabi–Yau Pairs

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Acta Mathematica Sinica,English Series 2020年第6期36卷 631-637页

作者： jános KOLLár Chen Yang XU Princeton University Princeton NJ 08544-1000USA MIT CambridgeMA 02139-4307USA

We prove that the irreducible components of the moduli space of polarized Calabi–Yau pairs are projective.

关键词： Polarized Calabi–Yau stable pairs Moduli spaces

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