A convenient synthesis of bis(phosphino)methanes: Formation of a nickel(II) bis(phosphino)methane monoxide complex

The reaction of (trimethylsilyl)methyl phosphines R₂PCH₂SiMe₃ with chlorophosphines ${\mathrm{ClPR}}_2^{\prime }$ provides ready access to a range of symmetrical or non-symmetrical diphosphinomethanes ${\mathrm{R}}_2{\mathrm{PCH}}_2{\mathrm{PR}}_2^{\prime }$. The products are obtained cleanly and can be used directly in the synthesis of transition metal complexes. This is illustrated by the preparation and structural characterization of the corresponding NiCl₂(P–P) derivatives.     

A Comparative Study of Two Ambulatory Core Temperature Assessment Methods

Background. Given the need to identify reliable non-invasive solutions for core temperature ambulatory monitoring, the purpose of this study was to evaluate the performance of zero-heat-flux (ZHF) temperature sensor on the forehead ($T_{\mathrm{COzhf}}$) by comparing it with intestinal temperature ($T_{\mathrm{COpill}}$) in different ambient and physiological conditions.Methods. Seven trained male subjects were followed during a 45-min rest period (STA) and a 25-min self-regulated cycling exercise performed in neutral (TMP, 22.8?°C) and hot (HOT, 38.5 °C) ambient temperature.Results.$T_{\mathrm{COzhf}}$ values differed from $T_{\mathrm{COpill}}$ of ?0.23 ± 0.13 in STA, 0.15 ± 0.30 °C in TMP and $0.28\pm 0.38$?°C in HOT. The 95% limits of agreement showed an acceptable bias between $T_{\mathrm{COzhf}}$ and $T_{\mathrm{COpill}}$ in STA (±0.26?°C), but not in TMP and HOT (±0.60 and ±0.75?°C).Conclusion. The non-invasive ZHF sensor gave an accurate estimation of $T_{\mathrm{COpill}}$ in steady state but not during exercise. However, complementary results let suppose that ZHF performance is not affected by ambient conditions and could be a relevant alternative for deep body temperature measurement during whole-body heat stress.     

Structural Analysis of a Trimer of β2-Microgloblin Fragment by Molecular Dynamics Simulations

A peptide ${\beta }_2$-${\text{m}}_{21?31}$, which is a fragment from residue 21 to residue 31 of ${\beta }_2$-microgloblin, is experimentally known to self-assemble and form amyloid fibrils. In order to understand the mechanism of amyloid fibril formations, we applied the replica-exchange molecular dynamics method to the system consisting of three fragments of ${\beta }_2$-${\text{m}}_{21?31}$. From the analyses on the temperature dependence, we found that there is a clear phase transition temperature in which the peptides aggregate with each other. Moreover, we found by the free energy analyses that there are two major stable states: One of them is like amyloid fibrils and the other is amorphous aggregates.     

The consequences of dominance and gene flow for local adaptation and differentiation at two linked loci

For a subdivided population the consequences of dominance and gene flow for the maintenance of multilocus polymorphism, local adaptation, and differentiation are investigated. The dispersing population inhabits two demes in which selection acts in opposite direction. Fitness is determined additively by two linked diallelic loci with arbitrary intermediate dominance (no over- or underdominance). For weak as well as strong migration, the equilibrium structure is derived. As a special case, a continuous-time continent–island model (CI model) is analyzed, with one-way migration from the continent to the island. For this CI model, the equilibrium and stability configuration is obtained explicitly for weak migration, for strong migration, for independent loci, and for complete linkage. For independent loci, the possible bifurcation patterns are derived as functions of the migration rate. These patterns depend strongly on the degree of dominance. The effects of dominance, linkage, and migration on the amount of linkage disequilibrium (LD) and the degree of local adaptation are explored. Explicit formulas are obtained for $D$   $(=x_1{x}_4-x_2{x}_3)$ and $r^2$ (the squared correlation in allelic state). They demonstrate that dominant island alleles increase $D$ and decrease $r^2$. Local adaptation is elevated by dominance of the locally adaptive alleles. The effective migration rate at a linked neutral locus is calculated. If advantageous alleles are dominant, it is decreased only slightly below the actual migration rate. For a quantitative trait that is determined by two additive loci, the influence of dominance on measures of differentiation is studied. Explicit expressions for $Q_{ST}$ and two types of $F_{ST}$ at equilibrium are deduced and their relation is discussed.