Phase diagram of Bi up to 140 kbars

The phase diagram of Bi has been studied by resistometric techniques in the temperature range of 30 to 300°K up to pressures of 140 kbars. Using the original Bridgman phase notation, the phase transitions I–II, II–III, I–III, III–IV and V–VI were observed. Two new phases, designated VIII and IX were observed in this region. The triple points occurring between I–II–III near 29.5 kbars and 160°K, between IV–V–VIII near 55 kbars and 240°K, between V–VI–VIII near 72 kbars and 255°K and between VI–VIII–IX near 135 kbars and 250°K. Earlier measurements were adjusted to the 1970 Drickamer pressure scale and compared to the present results. A phase diagram is proposed for pressures to 140 kbars. Calculations of the volume changes and latent heats of transformation are made near the triple points I–II–III, IV–V–VIII and V–VI–VIII using the measured volume changes of Bridgman for the I–II, IV–V and V–VI transitions. The latent heat associated with the III–IV transition was calculated using the volume data of Bridgman to be less than ? 2 cal/mol.     

GaP semiconducting-to-metal transition near 220 kbar and 298°K

Resistometric measurements were made on polycrystalline GaP to pressures above 250 kbar. Reproducible resistance changes of more than four orders of magnitude were observed near 220 kbar. This transition is in excellent agreement with the prediction of the Van Vechten-Phillips dielectric theory of electronegativity in covalent systems.     

Guarantees for the success frequency of an algorithm for finding Dodgson-election winners

In the year 1876 the mathematician Charles Dodgson, who wrote fiction under the now more famous name of Lewis Carroll, devised a beautiful voting system that has long fascinated political scientists. However, determining the winner of a Dodgson election is known to be complete for the Θ ₂ ^p level of the polynomial hierarchy. This implies that unless P=NP no polynomial-time solution to this problem exists, and unless the polynomial hierarchy collapses to NP the problem is not even in NP. Nonetheless, we prove that when the number of voters is much greater than the number of candidates—although the number of voters may still be polynomial in the number of candidates—a simple greedy algorithm very frequently finds the Dodgson winners in such a way that it “knows” that it has found them, and furthermore the algorithm never incorrectly declares a nonwinner to be a winner.     

Baryon pairs production ine + e − annihilation at\sqrt s = 2.4 GeV

Search for baryon pairs production ine ⁺ e ^? annihilation at \(\sqrt s = 2386 MeV\) is reported. The data relate to a luminosity of 161 nb^?1 collected by the DM2 experiment at DCI, the Orsay colliding ring. First measurements of directe ⁺ e ^? annihilation into \(\Lambda \bar \Lambda \) and ofe ⁺ e ^?→ \(p\bar p\) at this energy are presented. First observation of a goode ⁺ e ^?→ \(n\bar n\) candidate is reported and upper limits are given fore ⁺ e ^?→ \(n\bar n, \Lambda \bar \sum ^0 + c.c.\) and \(\Sigma ^0 \bar \Sigma ^0 \) .     

Evaluation of fully-functionalized diazirine tags for chemical proteomic applications

The use of photo-affinity reagents for the mapping of noncovalent small molecule–protein interactions has become widespread. Recently, several ‘fully-functionalized’ (FF) chemical tags have been developed wherein a photoactivatable capture group, an enrichment handle, and a functional group for synthetic conjugation to a molecule of interest are integrated into a single modular tag. Diazirine-based FF tags in particular are increasingly employed in chemical proteomic investigations; however, despite routine usage, their relative utility has not been established. Here, we systematically evaluate several diazirine-containing FF tags, including a terminal diazirine analog developed herein, for chemical proteomic investigations. Specifically, we compared the general reactivity of five diazirine tags and assessed their impact on the profiles of various small molecules, including fragments and known inhibitors revealing that such tags can have profound effects on the proteomic profiles of chemical probes. Our findings should be informative for chemical probe design, photo-affinity reagent development, and chemical proteomic investigations.

The chemical proteomic properties of five diazirine-based, fully-functionalized photoaffinity tags, including a newly developed, minimal tag, were compared. This study provides guidance for the development of new photoaffinity probes.     

Macroporous polystyrene-supported palladium catalyst containing a bulky N-heterocyclic carbene ligand for Suzuki reaction of aryl chlorides

Macroporous polystyrene (MPS)-supported 1-mesitylimidazolium chloride resin was prepared by reacting macroporous chloromethyl polystyrene with 1-mesitylimidazole as a supported N-heterocyclic carbene (NHC) precursor for the immobilization of a palladium catalyst. This MPS-supported NHC precursor readily formed a stable complex with Pd(OAc)2, which effectively catalyzed the Suzuki reaction of aryl iodide and bromides at room temperature and even aryl chlorides at elevated temperatures (100 degrees C). This catalyst showed reusability in the Suzuki reaction of aryl bromide.     

A global metabolite profiling approach to identify protein-metabolite interactions

Understanding the biochemical functions of proteins is an important factor in elucidating their cellular and physiological functions. Due to the predominance of biopolymer interactions in biology, many methods have been designed to interrogate and identify biologically relevant interactions that proteins make to DNA, RNA, and other proteins. Complementary approaches that can elucidate binding interactions between proteins and small molecule metabolites will impact the understanding of protein-metabolite interactions and fill a need that is outside the scope of current methods. Here, we demonstrate the ability to identify natural protein-metabolite interactions from complex metabolite mixtures by combining a protein-mediated small molecule enrichment step with a global metabolite profiling platform.     

Electrical behaviour and flux penetration in pressure quenched Cl doped CdS at 77 K: Superconductivity at high temperatures

Observations of magnetic field induced collapse of Meissner sized diamagnetism (χ??10^?3) with a coincident decrease in electrical conductivity in pressure quenched Cl doped CdS material at 77 K are reported. These results are consistent with the existence of superconducting regions in the specimens at this temperature.