Is a CImage C quadruple bond possible?

Ab initio computations Predict a minimum for a carbon-carbon quadruple bond in C2. While the computed C-C separation, 1.128 angstrom, fits Pauling's bond order-bond length relationship well, this result is an artifact of the restricted Hartree Fock theory.

Crystal packing and melting temperatures of small oxalate esters: the role of C-H center dot center dot center dot O hydrogen bonding

The simple dialkyl oxalates are generally liquids at room temperature except for dimethyl and di-tert-butyl oxalate which melt at 327 and 343 K. The crystal structures of diethyl, di-iso-propyl, di-n-butyl, di-tert-butyl and methyl ethyl oxalates were determined. The liquid esters were crystallized using the cryocrystallization technique. A comparison of the intermolecular interactions and packing features in these crystal structures was carried out. The crystal structure of dimethyl oxalate was redetermined at various temperatures. The other compounds were also studied at several temperatures in order to assess the attractive nature of the hydrogen bonds therein. A number of moderate to well defined C-H center dot center dot center dot O interactions account for the higher melting points of the two solid esters. Additionally, a diminished entropic contribution Delta S(m) in di-tert-butyl oxalate possibly increases the melting point of this compound further.

Investigation on the High Vacuum Tribological Characteristics of Surface Treated Nuclear Grade Stainless Steel Type AISI 316 LN at 25 to 500 degrees C

Although some researchers have published friction and wear data of Plasma Nitride (PN) coatings, the tribological behavior of PN/PN Pairs in high vacuum environment has not been published so far In order to bridge this knowledge gap, tribological tests under dry conditions have been conducted on PN/PN Pairs for varying temperatures of 25, 200, 400 and 500 degrees C in high vacuum (1.6 x 10(-4) bar) environment. The PN coatings showed good wear resistance layer on the ring surface. The PN coatings were removed only from the pin surface for all the tests since it contacts at a point. The friction and wear were low at lower temperatures and it eliminated adhesion between the contact surfaces until the coating was completely removed from the pin surface. (C) 2011 Journal of Mechanical Engineering. All rights reserved.

IR spectroscopy as a probe for C-H center dot center dot center dot X hydrogen bonded supramolecular synthons

Weak hydrogen bonds of the type C-H center dot center dot center dot X (X: N, O, S and halogens) have evoked considerable interest over the years, especially in the context of crystal engineering. However, association patterns of weak hydrogen bonds are generally difficult to characterize, and yet the identification of such patterns is of interest, especially in high throughput work or where single crystal X-ray analysis is difficult or impossible. To obtain structural information on such assemblies, we describe here a five step IR spectroscopic method that identifies supramolecular synthons in weak hydrogen bonded dimer assemblies, bifurcated systems, and p-electron mediated synthons. The synthons studied here contain C-H groups as hydrogen bond donors. The method involves: (i) identifying simple compounds/cocrystals/salts that contain the hydrogen bonded dimer synthon of interest or linear hydrogen bonded assemblies between the same functionalities; (ii) scanning infrared (IR) spectra of the compounds; (iii) identifying characteristic spectral differences between dimer and linear; (iv) assigning identified bands as marker bands for identification of the supramolecular synthon, and finally (v) identifying synthons in compounds whose crystal structures are not known. The method has been effectively implemented for assemblies involving dimer/linear weak hydrogen bonds in nitrobenzenes (C-H center dot center dot center dot O-NO), nitro-dimethylamino compounds (NMe2 center dot center dot center dot O2N), chalcones (C-H center dot center dot center dot O=C), benzonitriles (C-H center dot center dot center dot N C) and fluorobenzoic acids (C-H center dot center dot center dot F-C). Two other special cases of C-H center dot center dot center dot pi and N-H center dot center dot center dot pi synthons were studied in which the band shape of the C-H stretch in hydrocarbons and the N-H deformation in aminobenzenes was examined.

Characterization of type I interferon pathway during hepatic differentiation of human pluripotent stem cells and hepatitis C virus infection

Pluripotent stem cells are being actively studied as a cell source for regenerating damaged liver. For long-term survival of engrafting cells in the body, not only do the cells have to execute liver-specific function but also withstand the physical strains and invading pathogens. The cellular innate immune system orchestrated by the interferon (IFN) pathway provides the first line of defense against pathogens. The objective of this study is to assess the innate immune function as well as to systematically profile the IFN-induced genes during hepatic differentiation of pluripotent stem cells. To address this objective, we derived endodermal cells (day 5 post-differentiation), hepatoblast (day 15) and hepatocyte-like cells (day 21) from human embryonic stem cells (hESCs). Day 5, 15 and 21 cells were stimulated with IFN-alpha and subjected to IFN pathway analysis. Transcriptome analysis was carried out by RNA sequencing. The results showed that the IFN-alpha treatment activated STAT-JAK pathway in differentiating cells. Transcriptome analysis indicated stage specific expression of classical and non-classical IFN-stimulated genes (ISGs). Subsequent validation confirmed the expression of novel ISGs including RASGRP3, CLMP and TRANK1 by differentiated hepatic cells upon IFN treatment. Hepatitis C virus replication in hESC-derived hepatic cells induced the expression of ISGs - LAMP3, ETV7, RASGRP3, and TRANK1. The hESC-derived hepatic cells contain intact innate system and can recognize invading pathogens. Besides assessing the tissue-specific functions for cell therapy applications, it may also be important to test the innate immune function of engrafting cells to ensure adequate defense against infections and improve graft survival. (C) 2015 The Authors. Published by Elsevier B.V.

Immune responses against hepatitis C virus genotype 3a virus-like particles in mice: A novel VLP prime-adenovirus boost strategy

Chronic hepatitis C virus (HCV) infection represents a major health threat to global population. In India, approximately 15-20% of cases of chronic liver diseases are caused by HCV infection. Although, new drug treatments hold great promise for HCV eradication in infected individuals, the treatments are highly expensive. A vaccine for preventing or treating HCV infection would be of great value, particularly in developing countries. Several preclinical trials of virus-like particle (VLP) based vaccine strategies are in progress throughout the world. Previously, using baculovirus based system, we have reported the production of hepatitis C virus-like particles (HCV-LPs) encoding structural proteins for genotype 3a, which is prevalent in India. In the present study, we have generated HCV-LPs using adenovirus based system and tried different immunization strategies by using combinations of both kinds of HCV-LPs with other genotype 3a-based immunogens. HCV-LPs and peptides based ELISAs were used to evaluate antibody responses generated by these combinations. Cell-mediated immune responses were measured by using T-cell proliferation assay and intracellular cytokine staining. We observed that administration of recombinant adenoviruses expressing HCV structural proteins as final booster enhances both antibody as well as T-cell responses. Additionally, reduction of binding of VLP and JFH1 virus to human hepatocellular carcinoma cells demonstrated the presence of neutralizing antibodies in immunized sera. Taken together, our results suggest that the combined regimen of VLP followed by recombinant adenovirus could more effectively inhibit HCV infection, endorsing the novel vaccine strategy. (C) 2015 Elsevier Ltd. All rights reserved.

El arconte de Sicilia y el arconte bosporánico : estados dinásticos helenos a comienzos del siglo V a.C.

Resumen: En un contexto comparativo se van a analizar los motivos que dieron inicio a la aparición de estados monárquicos de gran territorialidad a finales del período arcaico en la periferia de la ecumene, Sicilia y bósporo cimérico. Sobre estas apariciones se va a tratar de presentar algunos argumentos que expliquen, por lo menos en parte, qué condujo a que estas polis se sometan en forma aparentemente voluntaria a un estado monárquico. Como hipótesis se plantea que los cimientos para este desarrollo van a manifestarse a fines del período arcaico como reacción contra procesos externos y/o de tensión social interna. En ese marco, se van a presentar en este trabajo el contexto y los motivos, que puedan arrojar luz sobre las razones que dieron origen y llevaron a la estabilización de estas construcciones políticas.

Lagerversuch von frischem bzw. tief gefrorenen gelagerten kalt geräuchertem Atlantischem Lachs (Salmo salar) in 200-g-Fertigpackungen mit sensorischer Beurteilung in Abhängigkeit von der Lagerzeit

After 4 months frozen storage at –18 °C cold smoked Atlantic salmon in consumer packages can hardly be differentiated from the freshly smoked product by sensory assessment by an expert panel and cannot be differentiated by consumers.

Veränderungen der Farbe und thermischen Stabilität der Muskelproteine von Räucherforellen während der Kühllagerung

The aim of the investigation was to prove if different farming conditions like conventional and organical farming of rainbow trout may cause differences in quality which are detectable by physical methods such as colour measurement and differential scanning calorimetry. Colour measurement revealed remarkable differences in lightness. Smoked trouts originating from conventionally farmed fish were much lighter than those of organically farmed trouts. This difference in L* could already be found when colour measurements were taken on the raw material. However, during chilled storage differences were equalized. Redness and yellowness were not significantly influenced by farming and did not change remarkably during chill storage. Based on earlier investigations on changes in thermal stability caused by heating, DSC curves of smoked trout could be used to verify that the core temperature of smoked fish had reached at least 60 °C during hot smoking process. This temperature is demanded by the guidelines of the German Food Code. In the DSC curves only the actin peak was still visible. All other proteins were obviously denatured during the hot smoking. When DSC curves were taken from smoked trout after different durations of chilled storage it could be seen that the denaturation temperature of actin decreased almost linearly with progression of storage time.

Nachweis von Parvalbuminen in Störgeweben

Parvalbumins, calcium-binding, heat-stable proteins of considerable allergenic potential, are occurring in high concentration in light muscle of many fish species. Lack of knowledge about parvalbumins in sturgeon tissues prompted us to study the distribution of this type of proteins in light and dark muscle, as well as in swim bladder and skin of Atlantic sturgeon, Acipenser oxyrhynchus, and three other sturgeon species. Results: Light and dark muscle of sturgeons contained water soluble proteins with following properties: (1) Great stability against heating at 70 or 80 °C. (2) Isolelectric points between 3.85 and 5.66. (3) Treatment of proteins separated by isoelectric focusing with the dye “stains all” gave blue protein bands. (4) The molecular mass was about 10 to 14 kDalton. (5) Concentration of acidic, heat-stable proteins was higher in light than in dark muscle. Taken together, these findings gave strong indication for the presence of parvalbumins in muscle tissue of sturgeons. This conclusion was corroborated by immunological tests. However, parvalbumin could not be detected in swim bladder tissue. Skin preparations showed only traces of parvalbumins, possibly resulting from residual muscle tissue.

ICES-Arbeitsgruppentreffen zum "Lebenszyklus und Fischerei von Nordseegarnelen" (WGCRAN)

Two years after their last meeting, scientists from North Sea neighbouring countries working on aspects of brown shrimp biology and fisheries gathered in Oostende, Belgium, to exchange information and results of their research. The group was established ten years ago by the International Council of the Exploration of the Sea (ICES)during the Warnemünde Annual Science Conference. Data on brown shrimp landings, fishing effort and resulting landings per unit effort were compiled. For the first time a computer model was demonstrated simulating the life cycle of C. crangon on basis of experimental and field data available. It will provide a means for testing different possible scenarios and their effect on the brown shrimp stocks. Catch predictions are not possible by this, as no stock assessments can yet be achieved for brown shrimp, and a number of topics have to be addressed by further research programmes. However, an approach of estimating the level of landings on basis of preceding climatological and hydrographical data seemed promising. Furthermore selectivity experiments and electric gear types were reported giving reason to assume, that progress is possible in the further reduction of bycatches. The assembling of already existing data in various countries and their evaluation was recommended besides the pursuing of the mentioned fields of research and proper reporting of EU log book data by all countries.

Veränderungen sensorischer und instrumenteller Parameter während der Gefrierlagerung von Ostseedorsch (Gadus morhua) bei unterschiedlichen Temperaturen

Changes in sensory and instrumental quality parameter sand in thawing drip, cooking drip and total drip loss of frozen stored Baltic cod fillets (Gadus morhua) at different storage temperatures were investigated. Cod fillets stored at –20 °C and –30 °C exhibited the lowest drip losses and obtained the highest sensory scores. Drip losses were found to be highest in cod fillets stored at –10°C and in double frozen fillets stored at –20 °C. These two experiments also gave the lowest sensory scores. The texture parameters increased during storage parallel with storage time. The waterbinding capacity was lowest at –10 °C and almost constant at –30 °C. There is a good correlation between the sensory scores for “tough” and the instrumental texture measurement for hardness and chewiness.

Qualitätsveränderung von rohen Fischfilets bei Kühlschrank-Lagerung

Raw fillets of saithe, red fish and salmon were stored over a period of 2 days at 6 to 9 °C before preparing by frying, deep-frying or cooking in a microwave oven. The raw and prepared fillets were tested for bacterial loads, TVBN (total volatile basic nitrogene) and for the sensorial status. It was shown that saithe and red fish started more rapidly to spoil under these conditions than salmon. The fillets showed growing bacterial populations and produced high amounts of TVBN. Sensory changes, especially in flavour and odour, took place but the scores kept in an acceptable range. The investigations indicated that it is possible to store raw fillets for 1 or even 2 days in refrigerator but due to the loss of quality it is recommended to use only really fresh fillets stored in very clean containers. It was further shown that it is very important to heat fillets sufficiently during cooking or frying in order to destroy all microorganisms and to obtain safe and stable meals.

Wnt and FGF signaling in C. elegans vulval cell lineage polarity

The interpretation of extracellular cues leading to the polarization of intracellular components and asymmetric cell divisions is a fundamental part of metazoan organogenesis. The C. elegans vulva, with its invariant cell lineage and interaction of multiple cell signaling pathways, provides an excellent model for the study of cell polarity within an organized epithelial tissue. Herein I discuss the interaction of Wnt and FGF signaling in controlling vulval cell lineage polarity with emphasis on the posterior-most cell that forms the vulva, P7.p.

The mirror symmetry of the C. elegans vulva is achieved by the opposite division orientation of the vulval precursor cells (VPCs) flanking the axis of symmetry. Opposing Wnt signals control the division patterns of the VPCs by controlling the localization of SYS-1/ β-catenin toward the direction of the Wnt gradient. Multiple Wnt signals, expressed at the axis of symmetry, promote the wild-type, anterior-facing, P7.p orientation, whereas Wnts EGL-20 and CWN-1 from the tail and posterior body wall muscle, respectively, promote the daughter cells of P7.p to face the posterior. EGL-20 acts through a member of the LDL receptor superfamily, LRP-2, along with Ror/CAM-1 and Van Gogh/VANG-1. All three transmembrane proteins control orientation through the localization of the SYS-1.

The Fibroblast Growth Factor (FGF) pathway acts in concert with LIN-17/Frizzled to regulate the localization of SYS-1. The source of the FGF ligand is the 1° VPC, P6.p, which controls the polarity of the neighboring 2° VPC, P7.p, by signaling through the sex myoblasts (SMs), activating the FGF pathway. The Wnt, cwn-1, is expressed in the posterior body wall muscle of the worm as well as the SMs, making it the only Wnt expressed on the posterior and anterior sides of P7.p at the time of the polarity decision. Both sources of cwn-1 act instructively to influence P7.p polarity in the direction of the Wnt gradient. The FGF pathway leads to the regulation of cwn-1 transcripts in the SMs. These results illustrate the first evidence of the interaction between FGF and Wnt in C. elegans development and vulval cell lineage polarity as well as highlight the promiscuous nature of Wnt signaling within C. elegans.

Der Einsatz von Flüssigrauch: eine neue Technologie Teil 3: Untersuchungen zur Lagerfähigkeit von mit Flüssigrauch hergestellten vakuumverpackten Räucherfischprodukten

The investigations showed that the shelf life of traditional smoked and vacuum-packed gutted mackerels, mackerel and herring fillets is similar to the corresponding vacuum-packed products smoked with liquid smoke. The storage temperature was 5 ± 0,5 °C. Under experimental conditions the storage time was 26 days for smoked gutted mackerels and more than 30 days for smoked fillets. Storage times of 20 to 25 days for these products are recommended. The microbiological and chemical results showed no differences between both technologies.