BACKGROUND Toxic element exposure and essential trace element consumption may have changed after the Chinese economy transformed to a market-oriented system.The objectives of this study were to measure urinary concentrations of toxic (arsenic,cadmium, lead) and essential trace (selenium, zinc, copper) elements among rural residents in Hainan, China and to examine if variations in economic devel...

Plant stoichiometry in relation to environmental factors has recently received increasing attention. However, regulations and variations of plant elements in different environments are not well understood. We investigated homeostasis and variation of macroelements (C, N, P, K, Ca, Mg, and S), essential microelements (Fe, Mn, and Zn) and non-essential elements (Al) in Quercus variabilis leaves a...

In the variational formulation of finite element models for mechanics problems, boundary conditions are classified as either essential or natural. The traction boundary conditions are identified as natural in many commonly-used finite element models. A valid finite element mode must satisfy explicitly the essential boundary conditions, since the latter are satisfied implicitly as a posteriori c...

Transcript-selective translational control of eukaryotic gene expression is often directed by a structural element in the 3' untranslated region (3'-UTR) of the mRNA. In the case of ceruloplasmin (Cp), induced synthesis of the protein by gamma interferon (IFN-gamma) in U937 monocytic cells is halted by a delayed translational silencing mechanism requiring the binding of a cytosolic inhibitor to...

The human T-cell leukemia virus type 1 Tax protein activates the expression of cellular immediate early genes controlled by the serum response element (SRE), which contains both the serum response factor (SRF) binding element (CArG box) and the ternary complex factor (TCF) binding element (Ets box). We show that TCF binding is necessary for Tax activation of the SRE and that Tax directly intera...

It has been demonstrated that the ordinary boundary layer elements play an essential role in the finite element approximations for singularly perturbed problems producing ordinary boundary layers. Here we revise the element so that it has a small compact support and hence the resulting linear system becomes sparse, more precisely, block tridiagonal. We prove the validity of the revised element ...

The key step in meiosis is synaptonemal complex formation, which mediates homologous chromosome alignment and synapsis. False pairing between homologous chromosomes produces infertility. Here, we present a crystal structure of the mouse meiosis-specific protein SYCE3, which is a component of the synaptonemal complex central element. Our studies show that functional SYCE3 most likely forms a dim...

Dynamic nite element schemes are analyzed for second order parabolic problems. These schemes can employ di erent nite element spaces at di erent time levels in order to capture time-changing localized phenomena, such as moving sharp fronts or layers. The dynamically changing grids and interpolation polynomials are necessary and essential to many large-scale transient problems. Standard, charact...