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Neural progestin receptors (PR) function in reproduction, neural development, neuroprotection, learning, memory and the anxiety response. In the absence of progestins, PR can be activated by dopamine (DA) in the rodent hypothalamus to elicit female sexual behaviour. The present study investigated mechanisms of DA activation of PR by testing the hypothesis that proteins from DA-treated hypothalami interact with PR in the absence of progestins. Ovariectomised, oestradiol-primed mice were infused with a D1-receptor agonist, SKF38393 (SKF), into the third ventricle 30 minutes prior to death. Proteins from SKF-treated hypothalami were pulled-down with glutathione S-transferase-tagged mouse PR-A or PR-B and the interactomes were analysed by mass spectrometry. The largest functional group to interact with PR-A in a DA-dependent manner was synaptic proteins. To test the hypothesis that DA activation of PR regulates synaptic proteins, we developed oestradiol-induced PR-expressing hypothalamic-like neurones derived from human-induced pluripotent stem cells (hiPSCs). Similar to progesterone (P4), SKF treatment of hiPSCs increased synapsin1/2 expression. This SKF-dependent effect was blocked by the PR antagonist RU486, suggesting that PR are necessary for this DA-induced increase. The second largest DA-dependent PR-A protein interactome comprised metabolic regulators involved in glucose metabolism, lipid synthesis and mitochondrial energy production. Interestingly, hypothalamic proteins interacted with PR-A, but not PR-B, in an SKF-dependent manner, suggesting that DA promotes the interaction of multiple hypothalamic proteins with PR-A. These in vivo and in vitro results indicate novel mechanisms by which DA can differentially activate PR isoforms in the absence of P4 and provide a better understanding of ligand-independent PR activation in reproductive, metabolic and mental health disorders in women.

This paper reports peculiar alternating augite-plagioclase wedges in basement dolerites of Lockne impact structure, Sweden. The combined microscopic and spectroscopic studies of the micro/nanoscale wedges reveal that these are deformation-induced features. First, samples showing wedges, 12 out of 18 studied, are distributed in the impact structure within a radius of up to 10 km from the crater center. Second, the margins between the augite and labradorite wedges are sharp and the {110} prismatic cleavage of augite develops into fractures and thereafter into wedges. The fractures are filled with molten labradorite pushed from the neighboring bulk labradorite grain. Third, compared to the bulk labradorite, the dislocation density and the residual strain in the labradorite wedges are significantly higher. A possible mechanism of genesis of the wedges is proposed. The mechanism explains that passing of the shock waves in the basement dolerite induced (i) formation of microfractures in augite and labradorite; (ii) development of the augite prismatic cleavages into the wedges, which overprint the microfracture in the labradorite wedges; and (iii) thereafter, infilling of microfractures in the augite wedges by labradorite.

Glacierised basins are significant sources of sediments generated by glacial retreat. Estimation of suspended sediment transfer from glacierised basins is very important in reservoir planning for hydropower projects in Himalaya. The present study indicates that storage and release of sediment in proglacial streams may categorise the pattern of suspended sediment transfer from these basins. Assessment of suspended sediment concentration (SSC), suspended sediment load (SSL) and yield has been undertaken for Dunagiri Glacier basin located in Garhwal Himalaya (30o33'20”N, 79o53'36”E), and its results are compared with the Gangotri and Dokriani glaciers sharing close proximity. Out of the total drainage basin area, about 14.3 % of the area is glacierised. Data were collected for five ablation seasons (1984–1989, barring 1986). The mean daily SSCs for July, August and September were 333.9, 286.0 and 147.15 mg/l, respectively, indicating highest concentration of mean daily suspended sediment in July followed by August. SSL trends were estimated to be 93.0, 57.0 and 21.3 tonnes. About 59% of the total SSL of the melt period was transported during the months of August and September. Sediment yield for the study basin was computed to be 296.3 t km−2 yr −1. It is observed that the cumulative proportion of SSC precedes the discharge throughout the melt season except in the year 1987. Release of SSL in terms of total load is less in the early part of melt season than in the later stage as compared to that of discharge. Diurnal variations in SSC reach their maximum at 2400 h, and therefore, SSC was found to be high during night (2000–0400 h). There was a good relationship between SSC and SSL with discharge for the ablation seasons (1988 and 1989). Mean monthly SSC and mean monthly SSL provide a good exponentional relationship with mean monthly temperature. Copyright © 2012 John Wiley & Sons, Ltd.

Heart disease is a leading cause of death in newborns and in adults. We previously reported that the G-actin-sequestering peptide thymosin β4 promotes myocardial survival in hypoxia and promotes neoangiogenesis, resulting in cardiac repair after injury. More recently, we showed that reprogramming of cardiac fibroblasts to cardiomyocyte-like cells in vivo after coronary artery ligation using three cardiac transcription factors (Gata4/Mef2c/Tbx5) offers an alternative approach to regenerate heart muscle. We have combined the delivery of thymosin β4 and the cardiac reprogramming factors to further enhance the degree of cardiac repair and improvement in cardiac function after myocardial infarction. These findings suggest that thymosin β4 and cardiac reprogramming technology may synergistically limit damage to the heart and promote cardiac regeneration through the stimulation of endogenous cells within the heart.

Objective To describe the spectrum of cardiac defects in monochorionic (MC) twins discordant for congenital heart disease (CHD) in a referral center population. Method Retrospective study of all twin gestations undergoing echocardiography between 2000 and 2009 at our institution. Results A total of 356 twin pairs were evaluated during the study period, 202 for suspected twin-twin transfusion syndrome (TTTS) and the remainder for other indications. Twenty-nine MC pairs were discordant for CHD: laterality defects, 24% [right (2) or left (3) isomerism (3), primitive heart (2)]; ventricular hypoplasia secondary to semilunar valve obstruction, 14% [hypoplastic left heart syndrome (2), severe pulmonary stenosis (PS) or atresia (2)]; valvar dysplasias in TTTS recipients, 27% [PS (4), mitral/tricuspid dysplasia (4)]; conjoining, 14% (4); and other developmental errors, 21% [conotruncal (1), tricuspid atresia (2), ventricular septal defect (2)]. Conclusions The spectrum of lesions in individuals assumed to be genetically identical and the disproportionate incidence of laterality and ventricular hypoplasia in this population leads us to propose potential mechanisms for the development of CHD in this population including local environmental or epigenetic factors influencing gene expression differentially, abnormal reciprocal laterality signaling between twinned embryos, or placental vascular factors affecting hemodynamics, either early in gestation or later in the setting of TTTS, leading to valvar lesions and ventricular hypoplasia. Copyright © 2011 John Wiley & Sons, Ltd.

CXCR7 (RDC1), a G-protein-coupled receptor with conserved motifs characteristic of chemokine receptors, is enriched in endocardial and cushion mesenchymal cells in developing hearts, but its function is unclear. Cxcr7 germline deletion resulted in perinatal lethality with complete penetrance. Mutant embryos exhibited aortic and pulmonary valve stenosis due to semilunar valve thickening, with occasional ventricular septal defects. Semilunar valve mesenchymal cell proliferation increased in mutants from embryonic day 14 onward, but the cell death rate remained unchanged. Cxcr7 mutant valves had increased levels of phosphorylated Smad1/5/8, indicating increased BMP signaling, which may partly explain the thickened valve leaflets. The hyperproliferative phenotype appeared to involve Cxcr7 function in endocardial cells and their mesenchymal derivatives, as Tie2-Cre Cxcr7(flox/-) mice had semilunar valve stenosis. Thus, CXCR7 is involved in semilunar valve development, possibly by regulating BMP signaling, and may contribute to aortic and pulmonary valve stenosis.

Phenol-modified cardanol–formaldehyde novolac resins have been synthesized using equal proportions of phenol and cardanol. To this mixture of phenol and cardanol, 0.6 and 0.8 mol of formaldehyde were added separately, under acidic conditions, at five different temperatures ranging between 80 and 120°C with an interval of 10°C. This was carried out for a maximum period of 6 h. The free formaldehyde and free phenol contents were determined at regular time intervals to check the completion of the reaction. The synthesized novolacs have been studied by infrared spectroscopic analysis (FT-IR). The reaction between cardanol, phenol, and formaldehyde was found to follow a second-order rate kinetics. The overall rate constant (k) increased with the increase of temperature. Based on the value of rate constants, various other parameters such as activation energy (Ea), change in enthalpy (Δ H) and entropy (Δ S), and free energy change (Δ G) of the reaction were also evaluated. It was found that the condensation reaction of phenol and cardanol with formaldehyde was nonspontaneous and irreversible. © 2010 Wiley Periodicals, Inc. Int J Chem Kinet 42: 380–389, 2010

Hypoxic heart disease is a predominant cause of disability and death worldwide. As adult mammals are incapable of cardiac repair after infarction, the discovery of effective methods to achieve myocardial and vascular regeneration is crucial. Efforts to use stem cells to repopulate damaged tissue are currently limited by technical considerations and restricted cell potential. We discovered that the small, secreted peptide thymosin beta4 (Tbeta4) could be sufficiently used to inhibit myocardial cell death, stimulate vessel growth, and activate endogenous cardiac progenitors by reminding the adult heart on its embryonic program in vivo. The initiation of epicardial thickening accompanied by increase of myocardial and epicardial progenitors with or without infarction indicate that the reactivation process is independent of injury. Our results demonstrate Tbeta4 to be the first known molecule able to initiate simultaneous myocardial and vascular regeneration after systemic administration in vivo. Given our findings, the utility of Tbeta4 to heal cardiac injury may hold promise and warrant further investigation.

Three samples of vinyl ester resins (VERs) were synthesized using bisphenol-A-based epoxy resins of varying epoxide equivalent weights (EEW) and acrylic acid in presence of triphenylphosphine as a catalyst at 80 ± 2°C. The cresyl glycidyl ether was used as reactive diluent during the synthesis of VERs. A suitable reaction mechanism was proposed and discussed for the reactions involving epoxide group and acid groups. This was further confirmed by infrared spectroscopic analysis. The maximum peak temperature from DSC were at 106.05°C, 114.20°C, and 128.86°C for benzoyl peroxide initiated VERs viz. samples V1CV, V2CV, and V3CV, respectively, increased with the increase of EEW of the parent epoxy resin. It has also been found that the films of VER having highest EEW of bisphenol-A epoxy resin showed best chemical resistance amongst all other VERs in this study. The mechanical properties such as hardness and flexibility also showed a similar trend. The thermal stability was found to decrease with the increase of EEW of bisphenol-A epoxy resin in the VERs. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

An epoxy resin based on nonglycidyl ether and varying content of carboxyl-terminated (poly)butadiene acrylonitrile copolymer was cured using an aromatic amine hardener. The ultimate aim of the study was to modify the brittle epoxy matrix by the liquid rubber to improve toughness characteristics. Fourier transform infrared spectroscopic analysis of the modified was performed to understand the structural transformations taking place during the uncured and cured stage of the modified systems. The decreasing trend in exothermal heat of reaction with increasing rubber content in the epoxy resin can be explained by the fact that the increase of carboxyl-terminated butadiene acrylonitrile copolymer (CTBN) modifier might induce a high reactivity of the end groups with the epoxide ring and resulting shorter curing times and, hence, the faster curing process than the unmodified resin. Tensile strength, impact strength, and elongation-at-break behaviors of neat as well as modified networks have been studied to observe the effect of rubber modification. Blends sample exhibits better properties as compared to pure epoxy resin in terms of increase in impact strength and elongation-at-break of the casting and gloss, scratch hardness, adhesion, and flexibility of the film. The improvement in these properties indicate that the rubber-modified resin would be more durable than the epoxy based on di glycidyl ether of bis-phenol-A and other epoxies. The films of coating based on epoxy with 15 wt % CTBN offered the maximum resistance toward different concentrations of acids, alkalies, and solvents as compared to the cured films of other blend samples. The thermal stability of the cycloaliphatic-based epoxy resin was increased with the addition of 15 wt % CTBN in epoxy matrix. Cycloaliphatic-based epoxy network modified with CTBN displayed two phase separated morphology with dispersed rubber globules in the matrix resin, i.e., they revealed the presence of two phase morphological features. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Cardanol-based novolac resins were separately prepared with different mole ratios of cardanol-to-formaldehyde with different acid catalysts. These resins were epoxidized with epichlorohydrin, in basic medium, at 120°C. The resins were, separately, blended with different weight percentages of carboxyl-terminated butadiene acrylonotrile copolymer and cured with polyamine. Structural changes during blending were studied by FTIR spectroscopic analysis. Coats–Redfern equation was utilized to calculate the kinetic parameters, viz., order of decomposition reaction (n), activation energy (E), pre-exponential factor (Z), and rate decomposition constant (k), for the decomposition of the samples. It was found that the degradation of the epoxies and their blend samples proceeded in two steps. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Five blend samples of cardanol-based epoxidized novolac resin containing varying concentrations of carboxyl-terminated poly(butadiene-co-acrylonitrile) (CTBN) ranging between 0 and 25 wt % with an interval of 5 wt % were prepared. The epoxidized novolac resin (ECF) was synthesized from the epoxidation of cardanol-based novolac-type phenolic resin (CF) with molar excess of epichlorohydrin (i.e., about 10 mol at 120°C in basic medium). The CF resin was synthesized with a molar ratio of 1 : 0.5 of CF using dicarboxylic acid catalyst such as succinic acid at 120°C for 5 h. The pure epoxy and its blend were cured with stoichiometric amounts of polyamine curing agent. The formation of various products during the synthesis of cardanol-based novolac resin, epoxidized novolac resin, and blending of epoxidized novolac resin with CTBN have been studied by Fourier transform infrared (FTIR) spectroscopic analysis. Further, a reaction mechanism for the step-growth reaction was proposed on the basis of the results of FTIR analysis. Also, the structures of CF and ECF were proposed on the basis of the results of nuclear magnetic resonance and MALDI-TOF mass spectroscopic analysis along with gel permeation chromatographic (GPC) analysis. GPC analysis resulted in Mn of 670 gmol−1. The blend sample having 15 wt % CTBN concentration showed minimum cure time, whereas the presence of CTBN in blend systems showed marginal change in the values of ΔH. A clear-cut two-step mass loss in dynamic thermogravimetric trace of unmodified and CTBN-modified systems was observed. Thermal stability of the blend sample containing 15 wt % CTBN into the pure epoxy resin was the highest among all other prepared systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Cardanol-based, novolac-type phenolic resins were synthesized with a cardanol-to-formaldehyde molar ratio of 1 : 0.7 with different dicarboxylic acid catalysts, including oxalic and succinic acids. These novolac resins were epoxidized with a molar excess of epichlorohydrin at 120°C in a basic medium. The epoxidized novolac resins were separately blended with different weight ratios of carboxyl-terminated butadiene–acrylonitrile copolymer (CTBN) ranging between 0 and 20 wt % with an interval of 5 wt %. All of the blends were cured at 120°C with a stoichiometric amount of polyamine. The formation of various products during the synthesis of the cardanol-based novolac resin and epoxidized novolac resin and the blending of the epoxidized novolac resin with CTBN was studied by Fourier transform infrared spectroscopy analysis. Furthermore, the products were also confirmed by proton nuclear magnetic resonance and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy analysis. The molecular weights of the prepared novolacs and their epoxidized novolac resins were determined by gel permeation chromatography analysis. The blend samples, in both cases, with 15 wt % CTBN concentrations showed the minimum cure times. These blend samples were also the most thermally stable systems. The blend morphology, studied by scanning electron microscopy analysis, was, finally, correlated with the structural and property changes in the blends. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Novolac resins having cardanol-to-formaldehyde mole ratios of 1:0.4, 1:0.5, and 1:0.6 were prepared by using aromatic sulphonic acid as the catalyst at four different temperatures ranging between 90°C and 120°C, with an interval of 10°C. Free formaldehyde and free phenol contents were determined at regular time intervals to check the completion of the reaction. The synthesized novolacs were characterized by Fourier-transform infrared spectroscopic analysis, nuclear magnetic resonance, and gel permeation chromatography. The reaction between cardanol and formaldehyde was found to follow second-order kinetics. The overall rate constant (k) increased with the increase of temperature. On the basis of the value of k, various other activation parameters such as activation energy (Ea), change in enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) of the reaction were also evaluated. It was found that the condensation reaction of cardanol and formaldehyde with aromatic sulphonic acid was nonspontaneous and irreversible. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 559–572, 2009

The curing kinetics of blends of diglycidyl ether of bisphenol A (DGEBA), cycloaliphatic epoxy resins, and carboxyl-terminated butadiene-acrylonitrile random copolymer (CTBN) in presence of 4,4′-diamino diphenyl sulfone (DDS) as the curing agent was studied by nonisothermal differential scanning calorimetry (DSC) technique at different heating rates. The kinetic parameters of the curing process were determined by isoconversional method given by Malek for the kinetic analysis of the data obtained by the thermal treatment. A two-parameter (m, n) autocatalytic model (Sestak-Berggren equation) was found to be the most adequate selected to describe the cure kinetics of the studied epoxy resins. The values of Ea were found to be 88.6 kJ mol−1 and 61.6 kJ mol−1, respectively, for the studied two sample series. Nonisothermal DSC curves obtained using the experimental data show a good agreement with that theoretically calculated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Resoles were prepared with different phenols, separately, with formaldehyde having phenol-to-formaldehyde molar ratio of 1 : 2 in basic medium at 70°C. These resoles were physically blended with different weight percentages of diglycidyl ether bisphenol-A (DGEBA)-epoxy resin. The blends were cured with 40, 50, and 60 wt % polyamide based on the total weight of the blend resin at 100°C. It was found that the blend system containing equal weight ratio of resole, prepared from p-cresol, and epoxy resins showed the least cure time with 40 wt % polyamide among all other blend systems. Also, the cured films of such blend systems showed the best chemical resistance, thermal stability, and hardness as compared to their other blend systems and blend counterparts. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Blend samples were prepared by physical blending of nonglycidyl-type epoxy resin with varying weight ratios of carboxyl-terminated butadiene acrylonitrile (CTBN) copolymer ranging between 0 and 25 wt%. The blend samples were cured with stoichiometric quantity of diamine. A comparative study of prepared blend samples by Fourier transform infrared (FTIR) spectroscopy showed the modification as a result of chemical reactions between cycloaliphatic epoxy, CTBN, and 4,4′-diamino diphenyl sulfone. The impact strength of the blend systems increased up to 15 wt% addition of CTBN in the blend and decreased thereafter. The toughness and elongation at break increased, whereas tensile strength decreased up to 20 wt% loading of CTBN in the blends. Two-phase morphology appeared with the incorporation of CTBN in the cycloaliphatic epoxy resin matrix. © 2008 Wiley Periodicals, Inc. Adv Polym Techn 26:258–271, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20106

Few known monogenic causes of non-syndromic congenital heart disease (CHD) have been identified. Mutations in NKX2.5 were initially implicated in familial cases of cardiac septal defects and subsequently, functionally significant NKX2.5 mutations were found in diverse forms of non-syndromic CHD. Similarly, mutations in GATA4, which encodes a cardiac transcription factor, were first identified in familial cases of cardiac septal defects. We hypothesize that individuals with non-syndromic CHD may harbor GATA4 mutations and that these mutations alter the biochemical properties of the protein. The coding region encompassing the six exons of GATA4 was screened in a study population of 157 patients with CHD. We identified several sequence variations in GATA4. We tested these novel sequence variations that altered evolutionarily conserved amino acids and other previously reported GATA4 mutations in various biochemical assays. The novel sequence variations had no biochemical deficits while a previously reported, but unstudied, missense mutation in GATA4 (S52F) functioned as a hypomorph in transactivation assays. We did not identify any novel GATA4 mutations in our patient population with non-syndromic CHD. Consistent with previous findings, GATA4 mutations that result in deficits in transactivation ability are consistently associated with CHD suggesting that normal transactivation properties of GATA4 are required for proper cardiac development.

Novolac resins having two different mole ratios of cardanol-to-formaldehyde (1:0.6 and 1:0.8) were prepared by using aliphatic tricarboxylic acid as catalyst at four different temperatures ranging between 100 and 130°C with an interval of 10°C. The synthesized novolacs were confirmed by infrared spectroscopic analysis with the appearance of characteristic groups of the novolac resin. The reaction between cardanol (C) and formaldehyde (F) was found to follow second-order rate kinetics as determined by two different approaches. The over all rate constant (k) increased with the increase of C/F molar ratio. Based on the value of k, various other kinetic parameters such as activation energy (Ea), change in enthalpy (ΔH), entropy (ΔS), and free energy (ΔG) of the reaction were also evaluated. The values of Ea and ΔH were found to be decreased with the increase of C/F molar ratio from 1:0.6 to 1:0.8. These values revealed the nature of the condensation reaction between cardanol and formaldehyde in presence of tricarboxylic acid catalysts. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:2730–2737, 2006

Resoles were prepared separately with different phenols, with formaldehyde having phenol-to-formaldehyde mole ratio of 1:2 in basic medium at 70°C. These resoles were physically blended with different weight percentages of diglycidyl ether of bisphenol-A (DGEBA)–epoxy resin. The blends were cured with 40, 50, and 60 wt % polyamide (based on total amount of the blended resin). Decomposition kinetics of blend sample was studied by dynamic thermogravimetric (TG) analysis. It was found that the degradation of most of the blend samples followed two-step second-order degradation kinetics with 50 wt % polyamide and varied reaction orders with 40 and 60 wt % polyamide and type of phenols used in the resole. The energy of activation (E) was found to be maximum with the blend system containing p-cresolic resole and epoxy. The value of preexponential factor (Z) decreased when phenolic resole was changed to p-cresolic resole in the blend. Also, the plotted values of E and Z were found to be in close resemblance with those obtained from calculated values. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102:4171–4176, 2006

Six blend samples were prepared by the physical mixing of epoxidized resole (EDR) with different weight ratios of carboxyl-terminated polybutadiene (CTPB) liquid rubber ranging from 0 to 25 wt % in intervals of 5 wt %. The formation of various reaction products during the curing of unblended EDR and CTPB-blended EDR were studied with Fourier transform infrared spectroscopy. The curing time at 100°C for the blend sample containing 15 wt % CTPB was the least among all of the blend samples. This blend sample, also, showed the highest initial degradation temperature, as obtained from thermogravimetric analysis thermograms, which indicated that it was the most thermally stable matrix system. The films of coatings based on the blend of EDR with 15 wt % CTPB offered the highest resistance toward different concentrations of acids and alkalis compared to the films having 5, 10, 20, and 25 wt % CTPB in the EDR/CTPB blends. Solvents showed almost the same behavior as acids and alkalis for these films except for hydrocarbon solvents such as mineral turpentine oil, toluene, and xylene. The resistance toward these solvents was poor and slightly inferior to those found with EDR unblended with CTPB. The tensile, flexural, and impact strengths of the molded specimens derived from the EDR/CTPB blends initially increased up to 15 wt % CTPB addition in the blend and then decreased, whereas the elongation at break remained constant for all blend compositions. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1802–1808, 2006

Cell (2013) 152, 570–583 Dev Cell (2013) 24, 206–214 Recent articles by Klattenhoff et al (2013) and Grote et al (2013) identify long non-coding RNAs, or lncRNAs, important for specifying the cardiac lineage. Depletion of a lncRNA, aptly named Braveheart, resulted in loss of beating cardiomyocytes during embryonic stem (ES) cell differentiation and failure to activate a key network of cardiac transcription factors. Immunoprecipitation of the protein complex associated with Braveheart revealed that the lncRNA physically interacts with epigenetic machinery that regulates cardiac gene expression. Similarly, a second lncRNA, Fendrr, also interacts with epigenetic regulators to promote proper cardiac gene expression and function in vivo in mice. These studies highlight the importance of lncRNAs during lineage commitment and provide a new layer of regulation involved in determining cardiac cell fate.

Films of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) each containing 25 wt % of linear low-density polyethylene (LLDPE) were extruded by melt blending in a single screw extruder (L/D ratio = 20:1). The samples were aged at 55, 70, 85, and 100°C for different time periods up to 600 h. The change in molecular structure and formation of oxygenated and unsaturated groups during thermo-oxidative degradation were investigated by infrared spectroscopy. Viscosity-average molecular weight (Mv) was found to decrease at slower rate in the initial hours of ageing, whereas on prolonged ageing, it decreased at a faster rate. In some blend samples, the tensile strength and elongation at break initially increased up to certain hours of ageing, and then decreased while in some blends both tensile strength and elongation-at-break varied differently. Increase in percent gel content supports the formation of cross-links between the molecular chains. Thermal stability of the samples also decreased with ageing time and temperature. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 59–70, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.10067

Cardanol-based epoxidized resole resins (ERCF) were synthesized by reacting resole-type phenolic resin (RCF) and epichlorohydrin in a basic medium, at 120oC. Resole-type phenolic resins were synthesized by reacting cardanol and formaldehyde (in molar ratios 1:1.3, 1:1.5, 1:1.7, 1:1.9, 1:2.1) in the presence of sodium hydroxide, as a catalyst, at five different temperatures ranging between 60 and 80oC with an interval of 5oC for a maximum period of 6 h. These prepared samples were cured using 15% polyamide as a curing agent at 120 ± 2oC for 1 h. The synthesized resins were characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopic analysis. The thermal properties of all these samples were studied by thermogravimetric analysis (TGA) at 10oC min−1. Decomposition kinetics was studied by various kinetic models for the synthesized compounds. The TG/DTG thermograms showed two-step decomposition behavior in all the samples of ERCF. In the present study, Coast–Redfern, Horowitz–Metzger, and Broido models have been used to calculate the activation energy (Ea) and preexponential factor (A) for different stages. The activation energy calculated from all the three models mentioned above were close to each other for the prepared ERCF.

Films of low-density (LD), high-density (HD) and linear low-density (LLD) polyethylenes have been prepared by melt blending in a single screw extruder (L/D ratio = 20 : 1). The film samples were aged at 50, 60, 70, 80, and 90°C for different time periods up to 750 h. A central composite rotatable design (CCRD) has been adopted to study the effect of blend composition, ageing time and ageing temperature on tensile strength using response surface methodology (RSM). Also, a linear second-order model has been developed to optimize and to study the interaction effects on tensile strength of the films. The optimized film sample had a maximum strength of 85.43 kg/cm2 when aged at 70°C for 333.5 h having 44.8, 27.7 and 27.7 wt.-% of LDPE, LLDPE and HDPE, respectively, in the blend system.

Proper morphogenesis and positioning of internal organs requires delivery and interpretation of precise signals along the anterior-posterior, dorsal-ventral, and left-right axes. An elegant signaling cascade determines left- versus right-sided identity in visceral organs in a concordant fashion, resulting in a predictable left-right (LR) organ asymmetry in all vertebrates. The complex morphogenesis of the heart and its connections to the vasculature are particularly dependent upon coordinated LR signaling pathways. Disorganization of LR signals can result in myriad congenital heart defects that are a consequence of abnormal looping and remodeling of the primitive heart tube into a multi-chambered organ. A framework for understanding how LR asymmetric signals contribute to normal organogenesis has emerged and begins to explain the basis of many human diseases of LR asymmetry. Here we review the impact of LR signaling pathways on cardiac development and congenital heart disease.

The carbon nanotube junctions have recently emerged as excellent candidates for use as the building blocks in the formation of nanoscale molecular electronic networks. While the simple joint of two dissimilar tubes can be generated by the introduction of a pair of heptagon-pentagon defects in an otherwise perfect hexagonal graphene sheet, more complex joints require other mechanisms. In this work we explore structural characteristics of complex 3-g38 point junctions of carbon nanotubes using a generalized tight-binding molecular-dynamics scheme. The study of pi-electron local densities of states (LDOS) of these junctions reveal many interesting features, most prominent among them being the defect-induced states in the gap.

Many-body potential energy surfaces (PESs) for describing atomic interactions in gas-solid and surface reaction dynamics are reviewed in this work. Initial PESs from the 1960s-1970s were restricted to a diatomic molecule interacting with a solid surface. Since the 1980s, a multitude of many-body reactive PESs, their parameterization, and their applications have been reported in the literature. Although we mention most of the PESs in general, we have chosen to describe only those that either have had general utility or have had staying power, i.e. they have been used widely by other research groups. The potentials discussed in the most detail are the Stillinger-Weber and Tersoff Si PESs, the Brenner hydrocarbon PES, and the embedded-atom method (EAM) style potentials for metals. We conclude that although these PESs have been used successfully in large-scale computer simulations, further development is needed in many-body PESs. In particular, the development of new functional forms for multicomponent reactive systems is required.

In this study, cardanol-based epoxidized novolac resins and methacrylic acid were used to produce cardanol-based epoxidised novolac vinyl ester resins. The reactions were conducted under nonstoichiometric condition using triphenylphosphine as catalyst in the temperature range of 80–100°C with an interval of 5°C. The first-order rate equation and mechanism based rate equation were examined. Parameters were evaluated by least square method. A comparison of mechnism based rate equation and experimental data showed an excellent agreement. Finally, Arrhenius equation and activation energy were presented. The specific rate constants, based on linear regression analysis, were found to obey Arrhenius equation. The values of activation energy, frequency factor, enthalpy, entropy, and free energy of the reaction revealed that the reaction was spontaneous and irreversible and produced a highly activated complex. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

The interaction of light with a polyatomic system is treated as a photon-scattering process in terms of time-correlation functions of transition operators. These are written as products of factors referring only to the molecule or the light field, so that the statistical properties of the polyatomic system and the light source can be easily incorporated. This procedure is developed for resonance absorption-emission and scattering of both thermal and coherent light.