نتایج جستجو برای: twinning

تعداد نتایج: 2757  

Journal: :British journal of industrial medicine 1988
P W Jones

Human populations and animals are often exposed to the airborne pollutants in plumes from incinerators. The incineration of chemical and other waste may release polychlorinated hydrocarbons, some of which have oestrogenic properties. Increased numbers of twins had been reported anecdotally in cattle at risk from plumes from two incinerators near the town of Bonnybridge in central Scotland and a...

Journal: :Human reproduction update 2000
N Abusheikha O Salha V Sharma P Brinsden

Monozygotic twinning is a relatively rare event in in-vivo conception, being estimated to occur in 0.42% of all births. The underlying mechanism for monozygotic twin formation is the division of the embryo early in its development. Separation of cells may theoretically occur before or after inner cell mass formation. In this analysis we report 11 cases of monozygotic twins resulting from IVF or...

2013
Jin-Wu Jiang Austin M. Leach Ken Gall Harold S. Park Timon Rabczuk

We present a surface stacking fault (SSF) energy approach to predicting defect nucleation from the surfaces of surface-dominated nanostructure such as FCC metal nanowires. The approach leads to a criterion that predicts the initial yield mechanism via either slip or twinning depending on whether the unstable twinning energy or unstable slip energy is smaller as determined from the resulting SSF...

Journal: :Zygote 2015
Gonzalo Herranz

In the dominant model, monozygotic (MZ) twinning is universally accepted as a post-fertilization event resulting from splitting of the embryo along its first 2 weeks of development. The stage at which splitting occurs determines chorionicity and amnionicity. A short history on how the model was built is presented, stressing the role played by some embryologists, in particular George Corner, in ...

Journal: :Twin research and human genetics : the official journal of the International Society for Twin Studies 2011
Gareth Baynam Peter Claes Jeffrey M Craig Jack Goldblatt Stefanie Kung Peter Le Souef Mark Walters

For decades the relationships of twinning and alterations in body patterning, such as laterality and asymmetry, have been investigated. However, the tools to define and quantify these relationships have been limited and the majority of these studies have relied on associations with subjectively defined phenotypes. The emerging technologies of 3-dimensional (3D) facial scanning and geometric mor...

2006
D. Canadinc H. Sehitoglu D. Niklasch

The tensile deformation response and texture evolution of aluminum alloyed Hadfield steel single crystals oriented in the h169i direction is investigated. In this material, the strain hardening response is governed by the high-density dislocation walls (HDDWs) that interact with glide dislocations. A microstructure-based visco-plastic self-consistent model was modified to account for mechanical...

Journal: :Nanoscale 2015
Byungil Hwang Mijeong Kang Subin Lee Christopher R Weinberger Phillip Loya Jun Lou Sang Ho Oh Bongsoo Kim Seung Min Han

In this study, we report the size-dependent transition of deformation twinning studied using in situ SEM/TEM tensile testing of defect-free [110] Au nanowires/ribbons with controlled geometry. The critical dimension below which the ordinary plasticity transits to deformation twinning is experimentally determined to be ∼170 nm for Au nanowires with equilateral cross-sections. Nanoribbons with a ...

2012
Syuichi Ooki

The purpose of the present study was to examine the effect of single embryo transfer (SET) in assisted reproductive technology (ART) on the reduction of the multiple pregnancy rate. We also estimated the monozygotic (MZ) twinning rates according to the SET diffusion indirectly. A reverse sigmoid curve was assumed and examined using nationwide data of SET from 2007 to 2009 in Japan. The multiple...

2015
Yao Li Liang Wan Kai Chen

An automated method has been developed to characterize the type and spatial distribution of twinning in crystal orientation maps from synchrotron X-ray Laue microdiffraction results. The method relies on a look-up table approach. Taking into account the twin axis and twin plane for plausible rotation and reflection twins, respectively, and the point group symmetry operations for a specific crys...

Journal: :Biology letters 2012
Ian J Rickard Andrew M Prentice Anthony J C Fulford Virpi Lummaa

In humans and other mammals, some females are more likely to experience twin pregnancies than others, but the reasons behind such individual variation are poorly understood. One hypothesis invokes variation in the dynamics of the insulin-like growth factor (IGF) system, which also regulates foetal growth. Using data from a rural African population living in a highly seasonal environment, we tes...

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