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A credit default swap (CDS) is a credit derivative that can be used as insurance against a reference entity's credit risk, where a reference entity is either a government or [...]

The effect of sulfur on the quasi-static and cyclic-dynamic fatigue properties of ethylene propylene diene monomer (EPDM) after three fatigue cycles were investigated under two specially designed test programs. The results turned out that sulfur as a coagent slowed down the vulcanization rate of EPDM compounds and reduced the chemical crosslinks. Further study on the effect of sulfur on the crosslinking behavior showed that this effect could be quantitatively described in linearity and became more distinct at higher crosslinking density. The addition of sulfur as a coagent improved the tearing performance of EPDM as a result of newly generated polysulfur bonds (-[S.sub.x]-). The strain and frequency sweep procedures were designed to study the dynamic rheological behavior and we obtained that the storage modulus of EPDM depended less on the addition of sulfur as well as sweeping temperature in sulfur-assisted curing system. The changes of loss factors obtained from the two sweep procedures were employed to survey the dynamic fatigue properties of EPDM, indicating that the fatigue behavior depended more on peroxide dosage than sulfur content, which might be due to the smaller proportion of polysulfur bridges in the final crosslinking structures of EPDM., INTRODUCTION Ethylene propylene diene monomer elastomer (EPDM) has become increasingly one of the most important synthetic rubbers since it was introduced into the market in the early 1960s. Compared with [...]

For hindered phenol (HP)/polymer-based hybrid damping materials, the unclear relationship between the structure of HP and the damping properties limits the application of such promising materials. Herein, three kinds of HPs with different chain lengths were synthesized to explore the mechanism. The structures of the HPs were confirmed by nuclear magnetic resonance spectrum, the Fourier Transform Infrared Spectroscopy (FT-IR), and X-ray Diffraction (XRD). For further prepared HP/polyurethane hybrids, FT-IR and XRD were adopted to confirm the hydrogen bonding interactions and micromorphologies. Moreover, molecular dynamics simulation was used to characterize the effects of chain length variation on the inter- and intramolecular hydrogen bonds (HBs) and the chain packing of the hybrids in a quantitative manner. Subsequently, combined with the dynamic mechanical analysis, the relationship between the chain length variation and the damping properties was established. The results showed that with the increasing of chain length, the intramolecular HBs between HPs can be prevented, and the loose HP chain within tight polymer matrix can be achieved, which results in a maximum increase of loss factor. While the homogeneity of the chain packing increases with the chain length increasing, which results in a decrease of the temperature range of loss factor [greater than or equal to] 0.3., INTRODUCTION Nowadays, vibration and noise issues are predominant in engineering systems and affect people's health [1-3]. The reduction or even elimination of the vibration and noise issues becomes more and [...]

The most tragic form of loss isn't the loss of security; it's the loss of the capacity to imagine that things could be different. (Bloch 1986) The world has long [...]

FK506-binding proteins (FKBPs) alter the conformation of proteins via cis--trans isomerization of prolyl-peptide bonds. While this activity can be demonstrated in vitro, the intractability of detecting prolyl isomerization events in cells has limited our understanding of the biological processes regulated by FKBPs. Here we report that FKBP25 is an active participant in the repair of DNA double-strand breaks (DSBs). FKBP25 influences DSB repair pathway choice by promoting homologous recombination (HR) and suppressing single-strand annealing (SSA). Consistent with this observation, cells depleted of FKBP25 form fewer Rad51 repair foci in response to etoposide and ionizing radiation, and they are reliant on the SSA repair factor Rad52 for viability. We find that FKBP25's catalytic activity is required for promoting DNA repair, which is the first description of a biological function for this enzyme activity. Consistent with the importance of the FKBP catalytic site in HR, rapamycin treatment also impairs homologous recombination, and this effect is at least in part independent of mTor. Taken together these results identify FKBP25 as a component of the DNA DSB repair pathway. Key words: DNA repair, prolyl isomerase, homologous recombination, FKBP, olaparib. Resume: Les proteines de liaison du FK506 (FKBP) modifient la conformation des proteines au moyen de l'isomerisation cis--trans des liens peptidiques de la proline. Alors que cette activite peut etre demontree in vitro, la grande difficulte a detecter les manifestations de l'isomerisation de la proline dans les cellules a limite notre comprehension des processus biologiques regules par les FKBP. Les auteurs rapportent ici que la FKBP25 est un participant actif dans la reparation des bris double brin (BDB) d'ADN. La FKBP25 influence le choix de la voie de reparation des BDB en favorisant la recombinaison homologue (RH) et en supprimant la renaturation simple brin. En accord avec cette observation, les cellules depourvues de FKBP25 forment moins de foyers de reparation comportant Rad51 en reponse a l'etoposide et a la radiation ionisante, et elles dependent du facteur de reparationrecombinaison Rad52 pour assurer leur viabilite. Ils ont trouve que l'activite catalytique de FKBP25 est requise pour favoriser la reparation d'ADN, ce qui constitue la premiere description de la fonction biologique de l'activite de cette enzyme. En accord avec l'importance du site catalytique de FKBP dans la RH, le traitement a la rapamycine diminue aussi la recombinaison homologue et cet effet est au moins partiellement independant de mTor. Dans leur ensemble, ces resultats identifient la FKBP25 comme element de la voie de reparation des BDB de l'ADN. [Traduit par la Redaction] Mots-cles : reparation d'ADN, prolyl isomerase, recombinaison homologue, FKBP, olaparib., Introduction FK506-binding proteins (FKBPs) are enzymes that catalyze the cis--trans isomerization of prolyl-peptide bonds to regulate substrate protein structure and function. Fifteen FKBPs are found in the human proteome and [...]

The color of pearl, one of the important quality traits, is determined by the shell nacre color of host mussel; however, the effective method to evaluate the effect of genetic breeding on the purity and uniformity of the nacre color was still limited to the freshwater mussel Hyriopsis cumingii. In this study, the characteristics of the [[upsilon].sub.1] band of polyene pigments in the colorful shell nacre and pearl samples from different selective generations of H. cumingii were detected by Raman spectroscopy. The results of this study showed that the number of peaks at the [[upsilon].sub.1] band of polyene pigments decreased gradually from 6-8 in the shell nacre and pearls with the color scheme of purple for wild mussels to 1 in those from the mussels of the F4 generation by genetic breeding. Similar results were also found in the samples with the color scheme of orange. But, no obvious peak of the [[upsilon].sub.1] band was detected in the samples with white color after four generations of selective breeding. Thus, it could be speculated that the single peak of the [[upsilon].sub.1] band in the Raman spectroscopy of shell nacre could be used as the sign of color uniformity to reflect the degree of purification in shell nacre color by genetic breeding. Meanwhile, the results showed that the samples with the same color scheme have a similar main peak at the [[upsilon].sub.1] band (ca. 1,508 [cm.sup.-1] for the purple color scheme and ca. 1,528 [cm.sup.-1] for the orange color scheme), suggesting that the polyene pigments in shell nacre and pearl with the same color scheme have the same length of C = C double bond. The length of C = C double bond were 12 and 9 in purple and orange samples, respectively. In summary, the results of this study support the conclusion that Raman spectroscopy is an efficient method to evaluate the genetic breeding for nacre color in H. cumingii. KEY WORDS: nacre color, genetic breeding, Hyriopsis cumingii, Raman spectroscopy, INTRODUCTION Color purity and uniformity of cultured pearls are important quality traits that directly affect the price of pearls. Cultured pearls are produced by pearl sacs, a special tissue developing [...]

In this report, we explored the effect of incorporating ureidopyrimidone (UPy) linkers in a series of polyimides (Pis) previously studied in our laboratory. The polymers consist of an aromatic diamine monomer with a methylene linker, 4,4'-methylenebis (2,6-dimethylaniline), used to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to decrease rigidity. The polymers were designed to exhibit thermal properties in between those of conventional aromatic PIs and polymers with wholly aliphatic ether diamine links, with an aim to improve the mechanical characteristics. Through dynamic mechanical analysis and differential scanning calorimetry, it is shown that the UPy linkers with their four-hydrogen bond sites are introduced to connect the chains in series. The connection strengthens the chain interactions and increases the range of the thermal and mechanical properties of the PI. Furthermore, the connecting regions are an important component to preserve the thermal stability of PIs while maintaining the processability. The polymers were characterized by FTIR, nuclear magnetic resonance, GPC, thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis, microhardness, and tensile testing., INTRODUCTION A series of thermoplastic polyimide with ureidopyrimidone linkers (PI-UPy) are synthesized and characterized in this work. The polymers are designed to have structural improvements and corresponding tractable properties. While [...]

Demolding is a necessary process in polymer micro molding, which requires energy for fracture of the bonds between the mold and the polymer. This often leads to structural defects due to an inappropriate combination of process parameters, including demolding temperature, embossing force or injection pressure, separation rate, and separation mode. In this article, we focus on the theoretical analysis and experimental optimization of the process parameters for polymer micro-part demolding from a zirconium (Zr)-based bulk metallic glass mold. We developed a theoretical model to predict the demolding work, in which we considered the effects of sidewall friction combined with deformation and adhesion. We also optimized the parameters for the demolding process based on the Taguchi method. The experimental results showed that the embossing force and the separation mode had significant effects on the demolding work of hot embossing. We determined the optimum process parameters and found that with these parameters the demolding work could be decreased to 10.36 mJ in this case., INTRODUCTION Plastic is a favorable material for fabricating microfluidic devices due to its low cost, available molding technologies, as well as wide range of mechanical properties and amenability to mass [...]

This paper considers themes of species maintenance and place engagement in Yanyuwa country, northern Australia. It traces the complexity of interpretations and relational contexts involved in places that are commonly--and we argue--misleadingly, referred to as increase and magic sites. Examining one specific place, at which people carry out maintenance rituals, we explore the complex bonds that unite Yanyuwa with the geography that is the Ancestral Hill Kangaroo. Not content with the classificatory habit of declaring actions either increase oriented or hunting magic, this research more fully explicates the relational substance of places that play a key role in ecological health. This is achieved by asking how might the profundity of a place of relational importance, such as a maintenance site, be better understood and written of in ways that convey an Indigenous ontology and epistemology? Keywords: maintenance sites, increase sites, place, aboriginal, kincentric ecology, Australia., INTRODUCTION Old people, old people like my father, my grandfather, they would go there, maybe at the end of the wet season when everything was fresh, they would go to [...]

Recently, we have studied polyimides (PIs) synthesized by incorporating an aromatic diamine monomer with a methylene linker, 4,4'-methylenebis(2,6-dimethylaniline), to make a robust main chain along with aliphatic polyetherdiamine backbone linkers to reduce rigidity. In this report, we incorporate a urea linkage into these materials in order to observe the effect of additional hydrogen bonding. The polymers are designed to exhibit thermal properties in between those of conventional aromatic PIs and polymers with wholly aliphatic ether diamine links. Herein, we demonstrate that the addition of 1,6 hexamethylene diisocyanate and the increase of hydrogen bonds at the urea linkage can be used to improve the thermal and mechanical properties of the PI. Furthermore, the imide ring is an important component to maintain the thermal stability characteristics in poly-imidepolyurea hybrids. The polymers were characterized by FTIR, thermomechanical and calorimetric analysis, micro-hardness, and tensile testing., INTRODUCTION A series of thermoplastic polyimide-polyureas (PIUs) with tractable properties and structural improvements are synthesized and characterized in this work. Polyimides (PIs) with highly ordered aromatic backbones demonstrate high thermal [...]

In this study, the effect of diamine molecular structure, attached to the multiwalled carbon nanotubes (MWCNTs), on the interfacial interactions of the MWCNTs and the epoxy matrix was studied. Pristine MWCNTs were successfully functionalized with multiple aliphatic and aromatic diamines. It has been found that, compared to aliphatic molecules, aromatic diamines can yield higher functionalization degree, due to higher activity and longer half-life of aromatic intermediates. However, at the same functionalization degree, the aliphatic ligands were more successful in reacting with epoxy chains and forming covalent bonds between the MWCNTs and the matrix. Considerable improvements were achieved in the mechanical properties of functionalized MWCNT-reinforced epoxy composites in comparison with the pristine MWCNT-reinforced composites. Fractography observations revealed distinct differences in the failure modes of reinforced composites after functionalization of the MWCNTs with diamines., INTRODUCTION Reinforced epoxy composites are of great interest in aerospace [1-3] and automotive [4-6] industries due to their valuable properties, including low density, thermal stability, considerably low water absorption, high [...]

Natural rubber (NR)-montmorillonite (MMT) nanocomposites were prepared by a novel in situ organomodified and latex compounding method, followed by melt compounding technique. Effects of cationic surfactant on MMT dispersion, curing characteristic, mechanical, and dynamical properties were investigated. The number of layers in the layered MMT stack was determined by Small-Angle X-Ray Scattering (SAXS). The dispersion of MMT tends to form high ordered structure in NR-MMT masterbatch when cationic surfactant of more than 4 phr was used. The morphology of Na-MMT shows partly intercalated and exfoliated structure in the matrix after mixing and hot pressing process with reduced number of layers compared to the pristine MMT. The use of cationic surfactant over 4 phr introduces a plasticizing effect resulting in the reduction of crosslink density, hardness and modulus, but increase in tensile strength due to higher interfacial adhesion between NR and MMT as determined by Maeir-Goritz model and Field Emission Scanning Electron Microscopy (FESEM). The optimum cationic surfactant loading is observed at 4 phr with the highest stable bonds, which result in the highest crosslink density, tear strength and storage modulus while the lowest Payne effect and tan delta at 60[degrees]C., INTRODUCTION After the successful work of Toyota research groups on the preparation of polyamide 6 (PA6)-montmorillonite (MMT) nanocomposites [1]. layered silicate has been increasingly used as reinforcing filler for rubbers [...]

In-mold coating (IMC) is applied to compression molded sheet molding compound (SMC) exterior automotive or truck body panels as an environmentally friendly primer to make the part conductive for subsequent electrostatic painting operations. The coating is a thermosetting liquid that when injected onto the surface of the part cures and bonds to provide a smooth conductive surface. In order to identify the processability of IMC for SMC, it is essential to predict the time available for flow, that is the time before the viscosity starts to increase as well as the time when the coating has enough structural integrity so that the mold can be opened without damaging the part surface (mold opening time). In the present work, we study cure behavior of IMC based on differential scanning calorimetry and rheological experiments and show its relevance to both flow and mold opening time for the IMC process during SMC compression molding., INTRODUCTION In recent years, the processing of thermosetting resins has received increased attention from automotive and aerospace industries as excellent choices for lightweight materials. Unlike the processing of thermoplastic materials, [...]

The emerging applications of hydrogels in flexible devices require it possess multifunctional properties including stable mechanical and functions under various deformations or external environments. Herein, a multifunctional polyvinyl alcohol/M-alginate/PAM hydrogel with very excellent mechanical properties and sensing functions was fabricated by introducing multiple pairs of toughing mechanisms into triple network (TN). The multiple supramolecular physical networks work as sacrificial networks to toughen the materials when hydrogel deforms. The broken bonds can reform upon unloading endowing the recovery of hydrogels' properties and functions with the assistance of the elastic covalent network. The optimal TN hydrogels are extremely tough (a fracture strength of 512 kPa, a fracture toughness of 3 M J/[m.sup.3]) and recoverable from fatigue damage (~77% toughness recovery after 5 min resting at room temperature). The presence of abundant ionic species endows the tough and recoverable TN hydrogels high ionic conductivity and high sensitivity as strain sensors. Moreover, such TN hydrogels with multi-bond crosslinking in three networks can potentially guarantee stable mechanical and sensor functions under various deformations or external environments compared to the DN candidates. This work provides a simple strategy for fabricating multifunctional hydrogels with high stability to fulfill its flexible devices applications., INTRODUCTION Ionic conductive hydrogels with polymer networks swollen with electrolyte solutions have been explored for applications in flexible devices, including ionic skin sensors and hydrogel-based electrolytes for energy storage devices [...]

In recent years, lacquer chemistry stimulated more attention from the scientific community due to its environmental friendly applications. Additionally, the 'laccol' possesses promising radiation resistance due to its highly crosslinked polymer network. In nature, lacquer polymerization is induced via enzymatic radical initiation. Herein, as a novel approach, lacquer polymer was synthesized via cationic polymerization with aluminum chloride-ethyl acetate coinitiator. This approach was further improved by polymerizing copolymers of laccol and styrene designed for use in radiation-hard materials. The infrared spectroscopic data clearly provide evidence for reactions with trans conjugated double bonds present in long side chain (988 and 966 [cm.sup.-1] are bending vibrations of conjugated alkenes) of laccol monomer accompanying polymerization. This was further verified with proton nuclear magnetic resonance analysis. An increase in hardness was observed for all the compositions: remarkably for neat laccol polymer, and 90% and 70% laccol-styrene copolymers after the gamma irradiation using Co-60 gamma irradiator. Properties such as thermal stability and hardness were improved after irradiation due to the increase in physical and small amounts of chemical crosslinking. Therefore, the developed materials are suitable candidates to produce radiation-hard polymer and copolymer coatings for aerospace operations, nuclear reactors, and medicinal and automobile sectors., INTRODUCTION For centuries, 'oriental' lacquer has been used as coatings [1-3] and paints [1, 4] in Asian countries due to its high solvent resistance [1], excellent toughness [1], and high [...]

Cracks may generate in epoxy resins, which can affect the comprehensive property and shorten service life. The problem is expected to be resolved by endowing epoxy resin with self-healing performance. Herein, a new kind of self-healing epoxy resin containing both Diels-Alder (DA) bonds and nitrile butadiene rubber (NBR) has been developed. The self-healing performance and mechanical properties of as-prepared epoxy resins are investigated by qualitative observation and quantitative measuring. Results reveal that the as-prepared epoxy resins exhibit excellent self-healing performance and multiple repair ability, and the self-healing behavior is based on dual actions of thermal reversibility of DA reaction and thermal movement of molecular chains. Furthermore, the thermoreversible DA bonds contribute much to the recovery of mechanical property, while the incorporated thermoplastic NBR accelerates the whole healing process. The self-healing efficiency of epoxy resins can be enhanced markedly by introducing thermoplastic NBR. In addition, the self-healing epoxy resins also exhibit outstanding reprocessing performance, which makes it possible of recycling waste epoxy resin., INTRODUCTION Due to the excellent properties such as good adhesion, high modulus, low shrinkage, and good corrosion resistance, epoxy resins have been used widely in fields of transportation, mechanics, construction, [...]

Deep vein thrombosis (DVT), caused by alterations in venous homeostasis, is the third most common cause of cardiovascular mortality, however, key molecular determinants in venous thrombosis have not been fully elucidated. Several lines of evidence indicate that DVT occurs at the intersection of dysregulated inflammation and coagulation. The enzyme ectonucleoside tri(di)phosphohydrolase (ENTPD1, also known as CD39) is a vascular ecto-apyrase on the surface of leukocytes and the endothelium that inhibits intravascular inflammation and thrombosis by hydrolysis of phosphodiester bonds from nucleotides released by activated cells. Here, we evaluated the contribution of CD39 to venous thrombosis in a restricted-flow model of murine inferior vena cava stenosis. CD39 deficiency conferred a greater than 2-fold increase in venous thrombogenesis, characterized by increased leukocyte engagement, neutrophil extracellular trap formation, fibrin, and local activation of tissue factor in the thrombotic milieu. This venous thrombogenesis was orchestrated by increased phosphorylation of the p65 subunit of NF-[kappa]B, activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome, and IL-1[beta] release in CD39-deficient mice. Substantiating these findings, an IL-1[beta]-neutralizing antibody or the IL-1 receptor inhibitor anakinra attenuated the thrombosis risk in CD39- deficient mice. These data demonstrate that IL-1[beta] is a key accelerant of venous thrombo-inflammation, which can be suppressed by CD39. CD39 inhibits in vivo crosstalk between inflammation and coagulation pathways and is a critical vascular checkpoint in venous thrombosis., Introduction The cell-surface enzyme ectonucleoside tri(di)phosphohydrolase-1 (ENTPD1), also known as CD39), is a key molecular factor protecting blood fluidity at the vessel-wall interface by catalyzing the hydrolytic cleavage of phosphodiester [...]

Wherein the author, a scholar of, among other things, Jewish American literature, has a chance meeting in New York City with a Rabbinicist and a Middle Eastern historian, and interweaves the narration of the encounter with ideas that have been maturing over the better part of the last decade about the field in order to spin a gripping yarn about the future of critical Jewish Studies. Keywords: critical Jewish studies, personal narrative, identity, institutional critique, historicism, privilege, disciplinary condescension, Nerd that I was in eighth or ninth grade, I spent a lot more time reading about quantum mechanics than I did hanging out with friends I didn't have. I [...]

Le processus d'integration et d'inclusion des personnes immigrantes comprend de multiples etapes et mobilise de nombreux acteurs individuels et institutionnels, notamment des groupes religieux qui ne se contentent pas d'offrir des services de nature religieuse, mais proposent egalement des activites de nature sociale ou communautaire. Prenant appui sur des donnees issue d'une recherche qualitative conduite aupres de pasteurs et de fideles d'assemblees protestantes evangeliques de la region metropolitaine de Montreal, nous insistons sur la diversite des activites que ces Eglises proposent a leurs membres qui vivent l'experience de l'immigration. Nous montrons qu'elles ne se contentent pas de dupliquer des services offerts par d'autres organismes, en particulier des organismes communautaires, mais qu'elles possedent des specificites qui leurs sont propres. Pour ce faire, nous mobilisons une conception relationnelle de la religion qui place au premier plan les interactions entre les individus. Ce faisant, nous mettons de l'avant l'idee selon laquelle la specificite et l'efficacite de leurs interventions resident dans la nature particuliere des liens sociaux qui se tissent entre les membres, liens qui pourront etre mobilises par les nouveaux arrivants a differents moments dans leur processus d'integration. Les Eglises jouent ainsi un role unique du fait de leur capacite a favoriser les interactions entre leurs membres, a activer les liens de solidarite, et a faire circuler des informations utiles aux nouveaux arrivants. Mots-cles : Immigration, integration, Eglises evangeliques, capital social. The integration and inclusion process of immigrants to a new society includes many steps, and involves many individuals and institutions, such as religious groups. These groups not only provide religious services but also offer social and community activities. Based on qualitative research conducted with pastors and members of protestant evangelical assemblies in Montreal's metropolitan area, we highlight the great diversity of activities offered by Churches to their immigrant members. We argue that they are not simply duplicating services offered by other organizations, in particular newcomers community organizations, but they possess their own specificities. In this regard, we apply a relational conception of religion that places interaction between individuals at the forefront of the analysis. By doing so, we suggest the idea that the specificity and effectiveness of their interventions with their immigrant members resides in the genuine nature of the social bonds that are woven between church members. These unique contacts can then be mobilised by newcomers throughout their integration process. Churches thus play a unique role because of their ability to foster interactions among members, to activate solidarity, as well as to help share useful information with newcomers. Keywords: Immigration, integration, Evangelical Churches, social capital., INTRODUCTION La pleine participation des personnes immigrantes a la societe d'accueil est un processus long et complexe dont l'issue depend de multiples facteurs et acteurs, autant individuels qu'institutionnels (services publics [...]

Transparent and intumescent polymer-silicate hydrogels were synthesized by free-radical polymerization, in the presence of the redox initiators system (potassium persulphate/sodium thiosulphate) and cross-linking monomer (N,N'-methylenebisacrylamide). Hydrogels obtained in such a manner were theologically tested and it was found that the same sample with a different sodium acrylate concentration polymerized faster when its content was lower. The spectroscopic and thermal analysis proved that the polymer combines with sodium silicate by hydrogen bonds and during thermal degradation only small polymer fragments and water molecules were released. NMR studies have shown that the content of water glass causes shorter relaxation times. Conducted fire tests showed that glass panes systems filled with the tested hydrogels meet the relevant construction standards and what is their big advantage, a thin 1 mm layer of polymer-silicate gel is sufficient for this purpose. We believe that these results will contribute to the development of intumescent hydrogels with enhanced fire-retardant properties., INTRODUCTION Aqueous solutions of soluble silicates, such as salts of a weak silicic acid and a strong base, for example, sodium, are alkaline. Therefore, as a result of the reaction [...]

In-mold coating (IMC) is a thermosetting liquid applied to compression molded sheet molding compound (SMC) exterior automotive or truck body panels as an environmentally friendly primer to improve surface quality and make the part conductive for subsequent electrostatic painting. The IMC is injected onto the surface of the SMC then cures and bonds to provide a smooth conductive and protective surface. In IMC as in many other reactive polymer processes, to have short cycle time while maintaining adequate flow time and pot life is required. This allows enough time to fill the mold before solidification. In this study, the effect of inhibitor (p-benzoquinone), initiator (f-butyl peroxybenzoate), and mold temperature on the flow and cure time of IMC materials has been experimentally investigated using differential scanning calorimeter. A cure model is developed based on experiments to predict inhibition and cure time. A multiple criteria optimization method was employed to identify the setting parameters of the controllable process variables that provide the best compromise (Pareto frontier [PF]) between flow and cure time. The analysis shows that simultaneous addition of initiator and inhibitor allows the molding to be performed at a higher temperature, which moves the PF toward the ideal location. Hence, minimizes the cure time and maximizes the flow time simultaneously., INTRODUCTION Sheet molding compound (SMC), consisting of a thermosetting resin (usually polyester or vinyl ester), particulate filler (usually calcium carbonate), and glass fiber reinforcement, is the material of choice for [...]

Photophysical and spectral properties of a new benzofuran-derivative-based fluorescent probe 1-(3-Hydroxybenzofuran-2-yl)-benzo[f]chromen-3-one (1-HBBC) were considered in various parameters of solvents, making use of UV-Vis absorption and fluorescence emission spectroscopy. The absorption and fluorescence emission peak maxima were observed between 260-349 and 400-485 nm, respectively, prompting Stokes' shift between 13 993 and 18 495 [cm.sup.-1]. Diverse solvent parameters have been utilized to understand the solvatochromism of 1-HBBC. This information is applied to understand the effects of the solvent, on the shifting in the spectra of 1-HBBC and access the execution of empirical solvatochromic models: the well-known Kamlet-Taft model and two recent Catalan models. Linear solvation energy relationships proposed by the Kamlet-Taft treatment for the 1-HBBC molecule indicate that it is appealing as a molecule for the hydrogen bond and solvent polarity properties it has exhibited. The models offer good statistical execution for all solvents studied in this work. A general decency of fit is found for benzofuran values for the models' contractions, whereas these solvents are incorporated directly into the solvatochromic analysis. These reductions are comparable for the Kamlet-Taft and Catalan 4P models but important for the Catalan 3P model. The results shown herein can be used for outlining new luminescent tests for nonpolar and polar microenvironment. Key words: electronic spectra, Kamlet-Taft, Catalan, acidity basicity, OLED. Nous utilisons les spectroscopies d'absorption UV-Vis et d'emission fluorescente pour differents solvants, afin d'examiner les proprietes photo-physiques et spectrales d'une nouvelle sonde fluorescente basee sur un nouveau derive de benzofurane, 1-(3-hydroxy-benzofurane-2-yl)-benzo[f|chromene-3-un (1-HBBC). Les maxima d'absorption et d'emission sont observes dans les bandes 260-349 et 400-485 nm respectivement, amenant un deplacement de Stokes de 13993-18485 [cm.sup.-1]. Divers parametres de solvant sont utilises pour comprendre le solvatochromisme de 1-HBBC. L'information ainsi obtenue permet de comprendre les effets du solvant sur le deplacement du spectre de 1-HBBC et donne acces a l'utilisation de modeles empiriques de solvatochromie : le modele bien connu de Kamlet-Taft et deux recents modeles, Catalan 3P et 4P. Les relations d'energie de solvatation proposees par Kamlet-Taft pour la molecule de 1-HBBC apparaissant comme molecule pour lien hydrogene et les proprietes de polarite des solvants sont illustrees ici, alors que les modeles offrent statistiquement de bonnes solutions pour tous les solvants utilises. On note un bon accord general pour les contractions de la solution de benzofurane predites par les modeles, lorsque les solvants sont introduits dans l'analyse solvatochromique. Ces reductions sont comparables entre les modeles Kamlet-Taft et Catalan 4P, mais le Catalan 3P est plus sensible au solvant. Les resultats presentes ici peuvent etre utilises pour developper de nouveaux tests pour les microenvironnements polaires et non polaires. [Traduit par la Redaction] Mots-cles: spectres electroniques, Kamlet-Taft, Catalan, acidite, basicite, DELO (diode electroluminescente organique)., 1. Introduction A deliberate examination of the solvent impacts is fundamental in the comprehension of the excited state behaviour of molecules. Some photophysical and photochemical qualities of coumarins were researched [...]

Predicting physicochemical properties of molecules is one of the fundamental tasks in chemical physics. Many predictive methods have been developed for correlating the molecular structures with their physicochemical properties. One of the simplest such methods involves topological indices. Edge connectivity index (or equivalently, reformulated Randic index), which is denoted as e, seems to be a good topological index for predicting the solvent accessible molecular volume and molar refraction of polycyclic aromatic hydrocarbons. In this paper, a closed-form formula for calculating the reformulated Randic: index e of benzenoid hydrocarbon chains (or simply, benzenoid chains, which represent a type of polycyclic aromatic hydrocarbons) is derived. Benzenoid chains with maximum (and minimum) e value are also determined from the collection of all benzenoid chains having fixed number of hexagonal rings. Moreover, an attempt is made to generalize the obtained results for reformulated bond incident degree indices. Key words: solvent accessible molecular volume, molar refraction, benzenoid chain, reformulated Randic: index, reformulated bond incident degree index. La prediction des proprietes physico-chimiques des molecules est un objectif parmi les plus fondamentaux de la chimie physique. Plusieurs methodes ont ete developpees pour correler les structures moleculaires avec les proprietes physicochimiques. Une des plus simples de ces methodes implique les indices topologiques. L'indice de connectivite des arretes (ou son equivalent, le nouvel indice de Randic:), denote par e, semble etre un bon indice topographique pour predire le volume moleculaire du solvant et la refractivite molaire des hydrocarbures aromatiques polycycliques. Ici, nous elaborons une formule pour calculer l'indice de Randic: des chaines d'hydrocarbures (ou, plus simplement, des chaines benzeniques qui representent un type d'hydrocarbures aromatiques polycycliques). Les chaines benzeniques avec une valeur maximale (minimale) de l'indice e sont egalement caracterisees a partir de la collection de toutes les chaines benzeniques ayant un nombre donne d'anneaux benzeniques. De plus, nous tentons de generaliser les resultats obtenus pour les nouveaux indices de degre incident sur la liaison. [Traduit par la Redaction] Mots-cles: refractivite molaire, chaine benzenique, nouvel indice de Randic:, nouvel indice de degre incident sur la liaison, volume moleculaire accessible du solvant., 1. Introduction Chemical compounds are associated with physical and chemical properties, and some of these compounds have biological activities. Actually, in the search for new antibacterial and various other medicinal [...]

A fluid-solid interaction model has been implemented by coupling two numerical methods--computational fluid dynamics (CFD) and discrete element method (DEM)--that capture the mesoscale behaviors of the fluid-solid system. The model is first validated by comparing the results of simulations with two types of experiments: free settling of a single sphere in water and formation of angle of repose of particles under water, which show its capability in modeling the behaviors of both particle phase and fluid phase. The verified model is then used to study factors affecting the soil erodibility, where case studies are designed for soil particles deposited inside a pipe and subsequently subjected to water flow-induced surface erosion. Influencing factors for soil erodibility, including particle diameter and interparticle bond, are analyzed. For cohesionless soils without bond strength, the critical shear stress is found to be linearly related to particle size; while for soils with bond strength, simulation results show that interparticle bonding largely decelerates the erosion process and causes a much lower erosion rate. To further the understanding of soil surface erosion under turbulent flow, the 'k-e' turbulence model has been successfully implemented for the fluid phase. Comparison between the laminar model and the turbulence model shows turbulence significantly accelerates the erosion process. Key words: fluid-particle interaction, computational fluid dynamics--discrete element method (CFD-DEM) model, k-e turbulence model, soil erosion, multiphase flow. Un modele d'interaction fluide solide a ete mis en oeuvre en couplant deux methodes numeriques, la dynamique des fluides computationnelle (CFD) et la methode des elements discrets (DEM), qui capturent les comportements a l'echelle meso du systeme fluide solide. Le modele est d'abord valide en comparant les resultats des simulations avec deux types d'experiences: le depot libre d'une sphere unique dans l'eau et la formation de l'angle de repos des particules sous l'eau, qui demontrent sa capacite a modeliser les phases. Le modele verifie est ensuite utilise pour etudier les facteurs affectant l'erodabilite du sol, ou des etudes de cas sont concues pour les particules de sol deposees a l'interieur d'une canalisation et ensuite soumises a l'erosion de surface induite par l'ecoulement de l'eau. Les facteurs d'influence de l'erodabilite du sol, y compris le diametre des particules et la liaison entre particules, sont analyses. Pour les sols sans cohesion sans resistance de liaison, la contrainte de cisaillement critique est liee lineairement a la taille des particules; tandis que pour les sols ayant une force d'adherence, les resultats de la simulation montrent que la liaison entre les particules ralentit considerablement le processus d'erosion et entraine un taux d'erosion beaucoup plus faible. Pour mieux comprendre l'erosion de la surface du sol sous ecoulement turbulent, le modele de turbulence <> a ete mis en oeuvre avec succes pour la phase fluide. La comparaison entre le modele laminaire et le modele de turbulence montre que la turbulence accelere de maniere significative le processus d'erosion. Mots-cles: interaction fluide-particules, modele dynamique des fluides computationnelle--methode des elements discrets (CFD-DEM), modele de turbulence k-e, erosion du sol, ecoulement polyphasique., 1. Introduction Interactions between fluid and particulate solid materials are very common yet complicated processes involved in multiple engineering fields, such as geotechnical engineering, mining, mechanical engineering, manufacturing, and chemical [...]

In this third installment of our examination of the infrared spectra of organic nitrogen compounds, we finish our look at the amine family by discussing secondary and tertiary amines. As we see, secondary amines can be distinguished from primary amines based on their infrared spectra. IR can also be used to differentiate between saturated secondary and aromatic secondary amines. We discover that tertiary amines are hard to see using infrared spectroscopy. We examine why, and what to do about it., As noted in our last installment (1), the amine functional group consists of carbon, hydrogen, and nitrogen atoms, and contain C-H and C-N bonds. Amines are divided into three categories, [...]

Nineteen enantiomer pairs of polychlorinated biphenyls (PCBs) with three or four chloro substituents about the central carbon--carbon bond form a stable subclass of compounds whose biological effects vary with their chirality. Optical rotations for this group ofPCBs were determined from density functional calculations employing extended atomic orbital gauge invariant basis sets. A comparison of these results with the experimental ones found from the literature for 10 of the pairs enabled the identification of their absolute configurations as analytes in gas chromatography studies. Key words: PCB atropisomers, optical rotation, absolute configuration, DFT. Dix-neuf paires d'enantiomeres de biphenyls polychlores (BPC) possedant trois ou quatre substituants chloro autour de la liaison carbone--carbone centrale forment une sous-classe de composes stables dont les effets biologiques varient en fonction de leur chiralite. Nous avons determine les valeurs de rotation optique pour ce groupe de BPC au moyen de calculs de fonctionnelle de la densite en utilisant des bases d'orbitales atomiques invariantes de jauge etendues. En comparant ces resultats aux resultats experimentaux tires de la litterature pour 10 des paires, nous avons ete en mesure d'etablir leur configuration absolue comme analytes dans des etudes de chromatographie en phase gazeuse. [Traduit par la Redaction] Mots-cles : atropisomeres de BPC, rotation optique, configuration absolue, DFT., Introduction Polychlorinated biphenyls (PCB) are a class of well documented environmental pollutants. (1) Because of their carcinogenic, neurotoxic, and endocrine disruption properties, their persistence and bioaccumulation pose a serious threat [...]

Melatonin (N-acetyl-5-methoxytryptamine) is a neurohormone that maintains circadian rhythms.sup.1 by synchronization to environmental cues and is involved in diverse physiological processes.sup.2 such as the regulation of blood pressure and core body temperature, oncogenesis, and immune function.sup.3. Melatonin is formed in the pineal gland in a light-regulated manner.sup.4 by enzymatic conversion from 5-hydroxytryptamine (5-HT or serotonin), and modulates sleep and wakefulness.sup.5 by activating two high-affinity G-protein-coupled receptors, type 1A (MT.sub.1) and type 1B (MT.sub.2).sup.3,6. Shift work, travel, and ubiquitous artificial lighting can disrupt natural circadian rhythms; as a result, sleep disorders affect a substantial population in modern society and pose a considerable economic burden.sup.7. Over-the-counter melatonin is widely used to alleviate jet lag and as a safer alternative to benzodiazepines and other sleeping aids.sup.8,9, and is one of the most popular supplements in the United States.sup.10. Here, we present high-resolution room-temperature X-ray free electron laser (XFEL) structures of MT.sub.1 in complex with four agonists: the insomnia drug ramelteon.sup.11, two melatonin analogues, and the mixed melatonin-serotonin antidepressant agomelatine.sup.12,13. The structure of MT.sub.2 is described in an accompanying paper.sup.14. Although the MT.sub.1 and 5-HT receptors have similar endogenous ligands, and agomelatine acts on both receptors, the receptors differ markedly in the structure and composition of their ligand pockets; in MT.sub.1, access to the ligand pocket is tightly sealed from solvent by extracellular loop 2, leaving only a narrow channel between transmembrane helices IV and V that connects it to the lipid bilayer. The binding site is extremely compact, and ligands interact with MT.sub.1 mainly by strong aromatic stacking with Phe179 and auxiliary hydrogen bonds with Asn162 and Gln181. Our structures provide an unexpected example of atypical ligand entry for a non-lipid receptor, lay the molecular foundation of ligand recognition by melatonin receptors, and will facilitate the design of future tool compounds and therapeutic agents, while their comparison to 5-HT receptors yields insights into the evolution and polypharmacology of G-protein-coupled receptors. The MT.sub.1 melatonin receptor differs markedly from 5-HT receptors and shows atypical ligand entry; its structure with various ligands sheds light on receptor specificity., Author(s): Benjamin Stauch [sup.1] [sup.2] , Linda C. Johansson [sup.1] [sup.2] , John D. McCorvy [sup.4] [sup.15] , Nilkanth Patel [sup.1] [sup.3] , Gye Won Han [sup.1] [sup.2] , Xi-Ping [...]

Methylation of cytosine to 5-methylcytosine (5mC) is a prevalent DNA modification found in many organisms. Sequential oxidation of 5mC by ten-eleven translocation (TET) dioxygenases results in a cascade of additional epigenetic marks and promotes demethylation of DNA in mammals.sup.1,2. However, the enzymatic activity and function of TET homologues in other eukaryotes remains largely unexplored. Here we show that the green alga Chlamydomonas reinhardtii contains a 5mC-modifying enzyme (CMD1) that is a TET homologue and catalyses the conjugation of a glyceryl moiety to the methyl group of 5mC through a carbon-carbon bond, resulting in two stereoisomeric nucleobase products. The catalytic activity of CMD1 requires Fe(ii) and the integrity of its binding motif His-X-Asp, which is conserved in Fe-dependent dioxygenases.sup.3. However, unlike previously described TET enzymes, which use 2-oxoglutarate as a co-substrate.sup.4, CMD1 uses l-ascorbic acid (vitamin C) as an essential co-substrate. Vitamin C donates the glyceryl moiety to 5mC with concurrent formation of glyoxylic acid and CO.sub.2. The vitamin-C-derived DNA modification is present in the genome of wild-type C. reinhardtii but at a substantially lower level in a CMD1 mutant strain. The fitness of CMD1 mutant cells during exposure to high light levels is reduced. LHCSR3, a gene that is critical for the protection of C. reinhardtii from photo-oxidative damage under high light conditions, is hypermethylated and downregulated in CMD1 mutant cells compared to wild-type cells, causing a reduced capacity for photoprotective non-photochemical quenching. Our study thus identifies a eukaryotic DNA base modification that is catalysed by a divergent TET homologue and unexpectedly derived from vitamin C, and describes its role as a potential epigenetic mark that may counteract DNA methylation in the regulation of photosynthesis. An algal TET dioxygenase homologue, CMD1, uses vitamin C as a glycerol donor to modify 5-methylcytosine and helps to regulate gene transcription in response to high light levels., Author(s): Jian-Huang Xue [sup.1] , Guo-Dong Chen [sup.1] , Fuhua Hao [sup.2] , Hui Chen [sup.1] [sup.3] , Zhaoyuan Fang [sup.1] , Fang-Fang Chen [sup.4] , Bo Pang [sup.5] , [...]