Histone underacetylation is an ancient component of mammalian X chromosome inactivation

Underacetylation of histone H4 is thought to be involved in the molecular mechanism of mammalian X chromosome inactivation, which is an important model system for large-scale genetic control in eukaryotes. However, it has not been established whether histone underacetylation plays a critical role in the multistep inactivation pathway. Here we demonstrate differential histone H4 acetylation between the X chromosomes of a female marsupial, Macropus eugenii. Histone underacetylation is the only molecular aspect of X inactivation known to be shared by marsupial and eutherian mammals. Its strong evolutionary conservation implies that, unlike DNA methylation, histone underacetylation was a feature of dosage compensation in a common mammalian ancestor, and is therefore likely to play a central role in X chromosome inactivation in all mammals.     

Chemical and structural effects on the electronic states of (Hg, Tl, Pb, Bi)-based cuprate superconductors

The electronic energy bands have been calculated for the new single-layer and triple-layer Hg-based superconductors, HgBa₂CuO₄ and HgBa₂Ca₂Cu₃O_y, for the analogous Tl-and Bi-based materials, and for hypothetical Pb-based materials. As one moves across the last row of the periodic table, from Hg to Bi,s- andp-derived bands pass below the Fermi energy, to influence hole doping of the copper oxide planes and transport in the other layers of the material. The dispersion of these bands is significantly affected by the crystal structure. The calculations were performed with a simple chemical model.     

The geometric non-linear analysis of thin-walled structures by finite strips

The geometric non-linear analysis of prismatic thin-walled structures is presented. The theory is based on the moderately large displacement assumption, giving non-linear strain-displacement relations, but linear curvature-displacement relations. The corresponding non-linear equilibrium equations are produced by the principle of stationary potential energy using the finite strip discretisation. The equilibrium equations are solved using incremental and incremental-iterative numerical methods. Thus for the simple case of the square plate in edge compression, the self-correcting incremental method gives satisfactory results. For more complex examples of loading and structural type, a variable load incremental-iterative method is adopted. It is shown that the finite strip method used in conjunction with this method can be applied in particular to problems containing load maxima.     

An evaluation of a television-delivered behavioral weight loss program: Are the ratings acceptable?

This experiment evaluated the efficacy of television delivery of a behavioral weight reduction program. Seventy-one overweight adults were randomly assigned to a live-contact weight loss group that was videotaped for viewing by other groups, a live-contact group that was not videotaped, a television-delivered group that observed the videotaped weight loss sessions, or a waiting-list control group. Participants in all 3 treatment groups lost significantly more weight during the 8-week treatment program than those in the waiting-list control group. There were no significant weight loss differences among the 3 treatment groups during the program. These weight changes were maintained at 3-month follow-up. At 15-month follow-up, the television-delivered group and the live-contact group maintained their weight losses, whereas the videotaped group did not. Cost-effectiveness analyses indicated that the television-delivered group received the most cost-effective treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Equipment selection and task assignment for multiproduct assembly system design

A multiproduct assembly system produces a family of similar products, where the assembly of each product entails an ordered set of tasks. An assembly system consists of a sequence of workstations. For each workstation, we assign a subset of the assembly tasks to be performed at the workstation and select the type of assembly equipment or resource to be used by the workstation. The assembly of each product requires a visit to each workstation in the fixed sequence. The problem of system design is to find the system that is capable of producing all the products in the desired volumes at minimum cost. The system cost includes the fixed capital costs for the assembly equipment and tools and the variable operating costs for the various workstations. We present and illustrate an optimization procedure that assigns tasks to workstations and selects assembly equipment for each workstation.     

Neonate plains garter snakes (Thamnophis radix) are attracted to conspecific skin extracts.

Several species of snakes aggregate in areas previously marked by conspecifics. However, species differences and sources of such chemical signals have received little attention. Methylene chloride-soluble substances from shed epidermis of adult plains garter snakes attracted neonate conspecifics, whereas similar extracts from a congener and a viperid did not. The functional significance of such conspecific aggregation may relate to location of hibernacula, foraging areas, osmoregulation, or predation avoidance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The linear multi-objective R&D project selection problem

A multi-objective model of the project-selection problem is described. The model departs from an earlier goal-programming formulation of the problem, which suggested Delphic methods for selection of priorities and aspiration levels. It is shown that the multiobjective formulation yields multiple nondominated solutions for the same problem solved by goal programming, whereas the goal-programming formulation revealed only one solution, and that the goal-programming solution is sensitive to choice of aspiration levels. The multiobjective model is recommended as a more general approach to the research and development project-selection problem, since it will develop a set of all nondominated solution. Subjective methods (such as the Delphic technique) can then be called for at a later point in the analysis to choose among alternative nondominated solutions     

Extending the dynamic range of phase contrast magnetic resonance velocity imaging using advanced higher-dimensional phase unwrapping algorithms.

Phase contrast magnetic resonance velocity imaging is a powerful technique for quantitative in vivo blood flow measurement. Current practice normally involves restricting the sensitivity of the technique so as to avoid the problem of the measured phase being 'wrapped' onto the range -pi to +pi. However, as a result, dynamic range and signal-to-noise ratio are sacrificed. Alternatively, the true phase values can be estimated by a phase unwrapping process which consists of adding integral multiples of 2pi to the measured wrapped phase values. In the presence of noise and data undersampling, the phase unwrapping problem becomes non-trivial. In this paper, we investigate the performance of three different phase unwrapping algorithms when applied to three-dimensional (two spatial axes and one time axis) phase contrast datasets. A simple one-dimensional temporal unwrapping algorithm, a more complex and robust three-dimensional unwrapping algorithm and a novel velocity encoding unwrapping algorithm which involves unwrapping along a fourth dimension (the 'velocity encoding' direction) are discussed, and results from the three are presented and compared. It is shown that compared to the traditional approach, both dynamic range and signal-to-noise ratio can be increased by a factor of up to five times, which demonstrates considerable promise for a possible eventual clinical implementation. The results are also of direct relevance to users of any other technique delivering time-varying two-dimensional phase images, such as dynamic speckle interferometry and synthetic aperture radar.     

0.9% sodium chloride injection with and without heparin for maintaining peripheral indwelling intermittent-infusion devices in infants

PURPOSE: Tachypnea in children is associated with respiratory disorders and nonrespiratory disorders such as cardiac disease, metabolic acidosis, fever, pain, and anxiety. Pulmonary embolism is seldom considered by pediatricians as a cause of tachypnea. PATIENTS AND METHODS: Three children of various ages with persistent tachypnea are described: a girl after orthopedic surgery for kyphoscoliosis, a boy with nephrotic syndrome, and a neonate with Hirschsprung disease. Other causes of tachypnea were diagnosed and treated before pulmonary embolism was considered. RESULTS: Ventilation-perfusion scanning appeared to be highly probable for pulmonary embolism in these patients. Anticoagulant therapy was started. CONCLUSION: Pulmonary embolism should be kept in mind in children with tachypnea, especially when other risk factors for venous thromboembolism are present, to avoid delay in anticoagulant treatment and a fatal outcome.