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The mechanisms of regioselective reductive openings of acetals were investigated in several model systems by a combination of Hammett plots, kinetic experiments, density functional calculations, and B-11 NMR. The regioselectivity of borane reductions of cyclic acetals can be controlled by the choice of borane. Lewis acid activation of BH3 center dot NMe3 increases the reaction rate and renders the

Multiangle light scattering (MALS) is a well-established technique used to determine the size of macromolecules and particles. In this study, different extrapolation procedures used in MALS were investigated with regard to accuracy and robustness in the obtained molar mass and rms radius. Three different mathematical transformations of the light scattering function referred to as the Debye, Zimm,

Masticatory efficiency was evaluated in 21 adults for four chewing parameters: mixing of a color-patterned chewing gum mass, shaping of a chewing gum mass, particle reduction of a silicone tablet, and number of chewing strokes before the first swallow of an almond. The results of these tests were correlated with the dimension of the pharyngoesophageal (PE) segment during swallow of liquid barium a

A description of mesoscopic fluctuations of the pairing gap in finite-sized quantum systems based on periodic orbit theory is presented. The size of the fluctuations are found to depend on quite general properties. We distinguish between systems where corresponding classical motion is regular or chaotic, and describe in detail fluctuations of the BCS gap as a function of the size of the system. Th

Different conceptions exist regarding the epidemiology and prognosis of liposarcoma, and several classification systems are in use. We analyzed a population-based, 25-year series of 43 patients with liposarcoma of the extremity or trunk wall. Follow-up was complete. The annual incidence was 0.12/10(5). The thigh was the most common location. One of 6 tumors was subcutaneous. Deep-seated tumors wer

Recent results on the 102 residue protein U1A show that protein aggregation is not always slow and irreversible but may take place transiently in refolding studies on a millisecond time scale. In this study we observe a similar aggregation behavior with the classical two-state protein CI2. Since both U1A and CI2 appear to fold directly from the coil at low protein concentrations, it is likely that

Objective. Type 11 collagen (01) is a candidate autoantigen implicated in the pathogenesis of rheumatoid arthritis (RA). Posttranslational glycosylation of CII could alter intracellular antigen processing, leading to the development of autoimmune T cell responses. To address this possibility, we studied the intracellular processing of CII for presentation of the arthritogenic glycosylated epitope

Question: The optimal use of the point intercept method (PIM) for efficient estimation of plant biomass has not been addressed although PIM is a commonly used method in vegetation analysis. In this study we compare results achieved using PIM at a range of efforts, we assess a method for calculating these results that are new with PIM and we provide a formula for planning the optimal use of PIM. Lo

Background: Psychosocial resources as well as lifestyle habits during pregnancy have been shown to effect the risk of having a small-for-gestational-age (SGA) child. Most previous studies are based on a single assessment of these exposures, which does not take into account the possibility of different effects during early add late stages of pregnancy. Methods: The impact of psychosocial and lifest

Phase III trials have demonstrated the efficacy of human papillomavirus (HPV) vaccines in preventing transient and persistent high-risk (hr) HPV infection and precancerous lesions. A mathematical model of HPV type 16 infection and progression to cervical cancer, parameterised to represent the infection in Finland, was used to explore the optimal age at vaccination and pattern of vaccine introducti

A commentary about the meaning of "One World Archaeology" today and the future of the World Archaeological Congress (WAC).

Global aging superimposed on existing infectious diseases and trauma will aggravate competition for health care resources to diagnose and treat osteoporosis. Efforts to implement public health measures are needed, but the targeted approach to assessment and treatment of high-risk individuals must also be refined.

The self-incompatible composite Senecio Jacobaea (ragwort) exhibits geographic variation in the frequency of rayed and discoid (rayless) individuals. Hybrid progenies from within- and between-morph crosses were established in a seminatural (garden) environment to determine whether patterns of segregation conform to single-gene predictions (as found in other Senecio species), whether the direction

The moss Hylocomium splendens has both sympodial and monopodial forms of growth. One aim of this study was to document the growth-form of shoots from different populations. A further aim was to discover the extent to which genetic or environmental factors determine whether monopodial or sympodial growth-form is predominant in a population. Switching between growth-forms within shoots occurs in mos

A PCR procedure has been developed for routine analysis of viable Salmonella spp. in feed samples. The objective was to develop a simple PCR-compatible enrichment procedure to enable DNA amplification without any sample pretreatment such as DNA extraction or cell lysis. PCR inhibition by 14 different feed samples and natural background flora was circumvented by the use of the DNA polymerase Tth. T