Gaussian effective potential for the U(1) Higgs model

In order to investigate the Higgs mechanism nonperturbatively, we compute the Gaussian effective potential of the U(1) Higgs model (“scalar electrodynamics”). We show that the same simple result is obtained in three different formalisms. A general covariant gauge is used, with Landau gauge proving to be optimal. The renormalization generalizes the “autonomous” renormalization for λ?⁴ theory and requires a particular relationship between the bare gauge coupling e _B and the bare scalar self-coupling λ _B. When both couplings are small, then λ is proportional to e⁴ and the scalar/vector mass-squared ratio is of order e², as in the classic 1-loop analysis of Coleman and Weinberg. However, as λ increases, e reaches a maximum value and then decreases, and in this “nonperturbative” regime the Higgs scalar can be much heavier than the vector boson. We compare our results to the autonomously renormalized 1-loop effective potential, finding close agreement in the physical predictions. The main phenomenological implication is a Higgs mass of about 2 TeV.     

Mass spectrometric characterisation of a condensation product between porphobilinogen and indolyl‐3‐acryloylglycine in urine of patients with acute intermittent porphyria

We document the presence of a previously unknown species in the urine of patients with acute intermittent porphyria (AIP). The compound was fully characterised by liquid chromatography tandem mass spectrometry. Interpretation of both full spectrum acquisition and product ion spectra acquired in positive and negative ionisation modes by quadrupole time of flight MS allowed for the identification of a condensation product arising from porphobilinogen (PBG, increased in the urine of AIP patients) and indolyl‐3‐acryloylglycine (IAG, derived from indolylacrylic acid and present in human urine). The structure was unequivocally confirmed through comparison between the selected reaction monitoring chromatograms obtained from the urinary species and the condensation product qualitatively synthesised in the laboratory. Owing to the large amounts of both PBG and IAG in urine of AIP patients, the possible ex vivo formation of PBG‐IAG in urine samples was evaluated. The product was spontaneously formed at room temperature, at 4 °C and even during storage at ?20 °C when spiking a control sample with PBG. A positive correlation was found between PBG and PBG‐IAG in samples collected from AIP patients. However, no correlation was found between PBG‐IAG and IAG. Purified PBG‐IAG did not form the characteristic chromogen after application of p‐dimethylaminobenzaldehyde in HCl, thus suggesting that the current techniques used to measure PBG in urine of AIP patients based on Ehlrich's reaction do not detect this newly characterised PBG‐IAG fraction. Copyright © 2015 John Wiley & Sons, Ltd.     

Small-angle X-ray scattering from wet gels prepared from co-hydrolysis of tetraethoxysilane and vinyltriethoxysilane

Small-angle X-ray scattering was used to study the structure of wet gels prepared from co-hydrolysis of tetraethoxysilane (TEOS) and vinyltriethoxysilane (VTES) in the VTES/(VTES + TEOS) molar ratio ranging from 0 to 1. The wet gels at pH = 6 behave as a mass-fractal structure with characteristic size ξ and fractal dimension D, both increasing with the amount of VTES from ξ = 6.78 nm and D = 2.25 for pure TEOS until an almost homogenous structure with ξ ~ 24.9 nm and D ~ 2.85 is obtained for the wet gel prepared with pure VTES. The mass-fractal structures are built up by small primary clusters of characteristic size between ~0.35 and ~0.85 nm, the size increasing with the quantity of VTES. These small particles of the gels are formed by a restructuring process of a few larger macromolecules in the stable sols (pH = 2) on passing from the acid to the increased-pH step of the process.     

Glucose biochip: dual analyte response in connection to two pre-column enzymatic reactions.

This article describes a novel 'Lab-on-a-Chip' protocol generating two electrophoretic peaks for a single analyte, based on the coupling of two different pre-column enzymatic reactions of the same substrate followed by electrophoretic separation of the reaction products. Such operation is illustrated for the measurement of glucose in connection to the corresponding glucose oxidase (GOx) and glucose dehydrogenase (GDH) reactions. The pre-column enzymatic reactions generate hydrogen peroxide and NADH species, that are separated (based on their different charges) and detected at the end-column amperometric detector. The peak current ratio can be used for confirming the peak identity, estimating the peak purity, addressing co-migrating interferences, and deviations from linearity. A driving voltage of 2000 V results in peroxide and NADH migration times of 93 and 260 s, respectively. Factors influencing the unique dual glucose response are examined and optimized. The concept can be extended to different target analytes based on the coupling of two pre-column reactions with electrophoretic separation of the reaction products.     

Solvent‐Slaved Protein Motions Accompany Proton but Not Hydride Tunneling in Light‐Activated Protochlorophyllide Oxidoreductase

H ⁺ but not H ^? : The reduction reaction of protochlorophyllide catalyzed by protochlorophyllide oxidoreductase features solvent‐slaved motions that control the proton‐ but not the hydride‐tunneling mechanism. These motions imply a long‐range dynamic network from the solvent to the enzyme active site that facilitate proton transfer (see picture, left). Motions for hydride transfer are more localized and are not slaved by the solvent (see picture, right).

     

Polarized ethylenes. IV. Synthesis of polarized ethylenes using thioamides and methyl dithiocarboxylates and their application to syntheses of pyrazoles,pyrimidines, pyrazolo[3,4-d]pyrimidines,and 5-aza[2.2.3]cyclazines

Polarized ethylenes having both electron-donating (an amino or a methylthio group) and electron-accepting (cyano, carbamoyl, methyl ester) groups on the adjacent two olefinic carbon atoms were prepared by the condensation of S-alkylthioamidinium salts or methyl dithiocarboxylates with the corresponding active methylene compounds in good yields. These polarized ethylenes were alternatively synthesized by the reaction of thioamides or methyl dithiocarboxylates with tetracyanoethylene oxide in good yields. Reactions of these polarized ethylenes with hydrazine or guanidine derivatives occurred smoothly to give the corresponding pyrazole and pyrimidine derivatives in good yields. The synthesis of 5-aza[2.2.3]cyclazine derivatives using polarized ethylenes is also described.     

Cayley's formula for multidimensional trees

This paper concerns extensions of Cayley's enumeration formula to a class of multi-dimensional tree-like simplicial complexes.     

Identification of Poly-<Emphasis Type="Italic">N</Emphasis>-Acetyllactosamine-Carrying Glycoproteins from HL-60 Human Promyelocytic Leukemia Cells Using a Site-Specific Glycome Analysis Method,Glyco-RIDGE

To elucidate the relationship between the protein function and the diversity and heterogeneity of glycans conjugated to the protein, glycosylation sites, glycan variation, and glycan proportions at each site of the glycoprotein must be analyzed. Glycopeptide-based structural analysis technology using mass spectrometry has been developed; however, complicated analyses of complex spectra obtained by multistage fragmentation are necessary, and sensitivity and throughput of the analyses are low. Therefore, we developed a liquid chromatography/mass spectrometry (MS)-based glycopeptide analysis method to reveal the site-specific glycome (Glycan heterogeneity-based Relational IDentification of Glycopeptide signals on Elution profile, Glyco-RIDGE). This method used accurate masses and retention times of glycopeptides, without requiring MS2, and could be applied to complex mixtures. To increase the number of identified peptide, fractionation of sample glycopeptides for reduction of sample complexity is required. Therefore, in this study, glycopeptides were fractionated into four fractions by hydrophilic interaction chromatography, and each fraction was analyzed using the Glyco-RIDGE method. As a result, many glycopeptides having long glycans were enriched in the highest hydrophilic fraction. Based on the monosaccharide composition, these glycans were thought to be poly-N-acetyllactosamine (polylactosamine [pLN]), and 31 pLN-carrier proteins were identified in HL-60 cells. Gene ontology enrichment analysis revealed that pLN carriers included many molecules related to signal transduction, receptors, and cell adhesion. Thus, these findings provided important insights into the analysis of the glycoproteome using our novel Glyco-RIDGE method.

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A new exact solution for colliding gravitational plane waves

A new exact solution of the vacuum Einstein equations describing the spacetime following the collision of two plane impulsive gravitational waves, each supporting a plane gravitational wave, is obtained. The solution has been extended prior to the instant of collision and the main features of the resulting space-time have been analyzed, using the Newman-Penrose formalism. It is shown that the result of the collision is the development of a singularity of the spacetime due to the simultaneous focussing of the two plane waves.