bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of genotype×sex interaction on linkage analysis of visual event‐related evoked potentials
Authors: Towne Bradford , Almasy Laura , Siervogel Roger M. , Blangero John
Published: November 2013

Autosomal genes contributing to variation in many complex traits are influenced by male or female physiological “environments.” Accounting for such genotype‐by‐sex (G×S) interactions has been shown to be important in quantitative genetic, segregation, and linkage analyses of a number of sexually dimorphic traits. In analyses of data simulated for GAW10, we showed that incorporating sex‐specific variance components into a variance components‐based linkage method increased the power to detect linkage in a trait that exhibited G×S interaction. The goals of this study of data from the Collaborative Study on the Genetics of Alcoholism (COGA) were to screen the event‐related brain potential (ERP) data from COGA participants for G×S interaction, and then to conduct variance components linkage analysis of ERP phenotypes showing evidence of G×S interaction using models incorporating sex‐specific variance components. Significant G×S interaction was found in four ERP phenotypes: N100 measured at occipital leads 1 and 2, and P300 measured at occipital leads 1 and 2. In linkage analyses of these traits, the most significant lod score found was that between N100 occipital lead 1 amplitude and marker D7S490. The peak lod score at the D7S490 locus was 2.45 without sex‐specific variance components, and 3.25 with sex‐specific marker and residual polygenic components.
Evidence for linkage and association to alcohol dependence on chromosome 19
Authors: Valdes Ana M. , McWeeney Shannon K. , Thomson Glenys
Published: November 2013

An association study on markers showing suggestive evidence for linkage to severe alcoholism was performed on the Collaborative Study on the Genetics of Alcoholism (COGA) data set. Our linkage study was restricted to the autosomal markers on chromosomes 2, 3, 4, 13, and 19, with low homozygosity (below 30%) and high identity‐by‐state sharing in affected sib pairs (ASPs). We used a strict phenotype definition, only individuals diagnosed as affected both on the ALDX1 (COGA criterion) and ALDX2 (ICD‐10) scales were used in the analyses. Linkage was assessed by excess identity‐by‐descent allele sharing in ASPs. The strongest evidence of linkage was detected on chromosome 19, in particular at markers D19S49 (p < 0.0001) and D19S431 (p < 0.002). An association study of allele and haplotype data was then carried out on chromosome 19 markers using affected‐family‐based controls. A haplotype defined by alleles at markers D19S49, D19S43, and D19S200 in chromosome 19 shows significant association (p < 0.003, odds ratio 2.82). Further, significant differences were observed in the distribution of the harm avoidance subscale among genotypes defined by D19S49 (p < 0.0001). These results provide evidence for the existence of a locus in chromosome 19 potentially involved in alcohol dependence susceptibility.
A more powerful method to evaluate p‐values in GENEHUNTER
Authors: Zhao Hongyu , Sheffield Leslie J. , Pakstis Andrew J. , Knauert Melissa P. , Kidd Kenneth K.
Published: November 2013

The determination of statistical significance in genetic linkage studies is complicated by many factors, such as missing individuals or uninformative markers, and the validity of theoretical results is often questionable. Although many simulation‐based methods have been proposed to determine empirically the statistical significance, they are either not generally applicable to complex pedigree structures, or not able to preserve the observed genetic information content at each locus in the pedigrees. We have developed and implemented a general and computationally efficient randomization procedure in GENEHUNTER that applies to arbitrary pedigree structure and preserves the observed information content at each locus. We applied this method to the Problem 1 data set of the Genetic Analysis Workshop 11. The performance of this new method was similar to the method implemented in GENEHUNTER‐PLUS, and both outperformed the conservative approach in GENEHUNTER.
Simulated data for a complex genetic trait (Problem 2 for GAW11): How the model was developed, and why
Authors: Greenberg David A. , Maccluer Jean W. , Spence M. Anne , Falk Catherine T. , Hodge Susan E.
Published: November 2013

This paper describes a simulated data set created as Problem 2 for GAW11. The generating model for Problem 2 involved two different genetic diseases, or “types,” in three separate populations. The two‐locus (2L) type results from the epistatic interaction of two genetic loci, and the three‐allele type, from a single locus with two disease‐causing alleles and one normal allele. Each type has two phenotypic forms: Mild and Severe. Both forms are subject to both genetic and environmental influences. The disease occurs in three different hypothetical populations, each with different disease allele frequencies and penetrances. In two populations there is also a fourth locus with an allele that is associated with the 2L type. Misdiagnosis can occur, but only after a family has already been ascertained through ≥ 2 “genetically” affected offspring. Finally, the three different populations are studied by four different hypothetical research groups. These groups each have their own ideas about how the disease is inherited and have therefore devised different ascertainment schemes based on those beliefs. Each research group collected 100‐family data sets, including data on 300 markers on six chromosomes and measurements on disease status and on the proposed two environmental factors. GAW participants were supplied with 25 random replicates of each data set.
Genetic model‐free linkage analysis using the maximum‐likelihood‐binomial method for categorical traits
Authors: Alcaïs Alexandre , Philippi Anne , Abel Laurent
Published: November 2013

Within the simulated data of the 11th Genetic Analysis Workshop, we searched for the genes controlling the disease. We analyzed 200 families from Studies 2 and 3 presenting both mild and severe forms of disease. Linkage analysis was performed using the recently developed genetic model‐free maximum‐likelihood‐binomial (MLB) method which overcomes the problem of multiple sibs by considering the sibship as a whole. The MLB allowed us to consider the disease as either a binary (affected/unaffected) or an ordered categorical (differentiating the two forms of disease and including effects of environmental factors) phenotype. In both studies, two regions provided evidence for linkage at a significance level below 10‐4. One is located on chromosome 3 (from D3G041 to D3G047), and the other on chromosome 5 (from D5G034 to D5G041). In Study 2, the most significant results were obtained by combining both forms of disease, suggesting that they are under the same genetic control, while in Study 3, the stronger results were obtained when considering severe subjects alone, suggesting that only the severe form is under the control of both locus B and C. The subsequent knowledge of the true model allowed a posterior interpretation of our results, in particular the difference in optimal coding schemes observed between Studies 2 and 3, and the failure to locate locus A.
Analysis of complex traits using neural networks
Authors: Bhat Ajita , Lucek Paul R. , Ott Jurg
Published: November 2013

A recently developed approach that employs artificial neural networks (ANNs) was applied to the simulated data set to identify sets of marker loci involved in disease etiology. In this implementation, ANNs are trained to predict the disease state (output) from the given genetic marker data (input). A contribution value (CV) for each locus is calculated from the weights that represent the strength of the connections for the trained ANN; a higher CV indicates a higher probability of linkage. The highest CV values were chosen as the most likely candidate regions involved in the disease.
Multipoint linkage analysis using the weighted‐pairwise correlation statistic
Authors: Commenges Daniel , Beurton‐Aimar Marie
Published: November 2013

The weighted pairwise correlation (WPC) approach provides simple and flexible non‐parametric tests for genetic linkage which may be adapted to qualitative, quantitative or age‐dependent traits. Although this statistic has often been used with identity‐by‐state (IBS) information, there is much to gain by using multipoint identity‐by‐descent (IBD) information. The purpose of this paper is to use the unified multipoint approach of Kruglyak et al. [1996] with the WPC statistic. We used the simulated data of a complex disease proposed in GAW11 (problem 2) to validate this approach and to compare the multipoint WPC to the EBS‐WPC and to the multilocus approach using the conventional non‐parametric statistics Spairs and Sall. The results suggest that the multipoint WPC may be the most powerful approach.
Analysis of simulated data: Evidence for genetic and environmental effects
Authors: Crockford Gillian P. , Iles Mark M. , Durham L. Kathryn , Bishop D. Timothy
Published: November 2013

We approached the simulation as though it were an international study with similar but not identical information being collected from different populations. In keeping with this we analyzed one replicate from each population. Initially we examined the risk of disease in relatives of cases to determine whether the disease appeared to be “more genetic” in one population than in the others and we examined the evidence for environmental risk factors in each population. Non‐parametric linkage analysis and transmission/disequilibrium testing (TDT) were used to search for loci linked to the disease in each population. Using these methods we identified several candidate regions for a susceptibility gene which on examination of the answers are explicable in terms of the underlying model.
Hunting genetic diseases: Exploring a multistage approach to identifying disease loci
Authors: Garcia Melissa E. , Haines Jonathan L.
Published: November 2013

Genomic screen data for a hypothetical disease was used in a two‐stage analysis to search for disease loci. We performed both trait‐model‐dependent and trait‐model‐free analyses to test their relative power. Results of our first‐stage screen in 200 families suggested 13 regions for further analysis. Second‐stage follow‐up in another 200 families confirmed a single region on chromosome 3 near marker D3G045 with a combined lod score across all 400 families of 6.24 and a sib‐pair maximum lod score (MLS) of 4.79. The MLS were highly correlated with both the autosomal dominant and autosomal recessive lod scores in all data sets, suggesting that both trait‐model‐dependent and trait‐model‐free methods can be useful for identifying candidate regions for complex disease loci. Reanalysis of the data using alternative sampling schemes suggested that sampling variation has a significant effect on locus detection.
A joint test of linkage and gene×environment interaction, with affected sib pairs
Authors: Gauderman W. James , Morrison John L. , Siegmund Kimberly D. , Thomas Duncan C.
Published: November 2013

In the presence of gene×environment (G×E) interaction, the expected proportion of alleles shared identical by descent at a linked marker locus by a pair of affected sibs depends on the exposure profile of the two sibs, i.e., whether both are exposed to E, only one is exposed, or neither are exposed. In this paper, we propose an extension of the commonly used mean test of linkage to test for differential identical‐by‐descent (IBD) sharing across sib‐exposure profiles. The method can be viewed as a test for linkage in the presence of G×E interaction, or as a test for G×E interaction in the presence of linkage. Applied to the simulated GAW11 data, our method successfully localized disease locus C and its interactive relationship with environmental factor E1. At the 5% significance level, use of our method led to increased power to detect linkage (56%) to this disease locus compared to use of the standard mean test (32%); at the 0.001 significance level, the corresponding power estimates were 20% and 4%, respectively. For a gene that interacts with an environmental factor, we conclude that use of the environmental factor in linkage analysis can improve detection rates while also providing information about underlying mechanisms.
Impact of family structure on the power of linkage tests using sib‐pair methods
Authors: Goddard Katrina A.B. , Goode Ellen L. , Rozek Laura S. , Jarvik Gail P.
Published: November 2013

This analysis sought to determine the impact of specific ascertainment criteria based upon nuclear family affectation structures. Specifically, we evaluated the predicted and observed proportion of alleles shared identical by descent conditional on the number of affected and unaffected siblings in a pedigree, and compared sib‐pair method linkage results under two ascertainment schemes, random vs. selected ascertainment, for this simulated complex genetic disease. These results suggest that samples differing in the composition of affected and unaffected siblings in the family will differ in their power to detect linkage. An effect of sampling scheme on power to map using affected‐sib‐pair methods should be considered when a reported linkage is not found in another study population.
Validation of linkage by sampling based on environmental exposures
Authors: Greenwood Celia M.T. , Brewer Carl G. , Morgan Kenneth
Published: November 2013

After detecting linkage in one sample, most researchers will attempt to validate this finding in another sample. Three strategies for validating a primary linkage were compared, with a focus on methods that might be appropriate in the presence of gene×environment interaction. First, a validation sample was collected and analyzed using the same ascertainment procedure and methods as the primary sample. Second, a sample of families with particular exposure patterns were ascertained subsequent to a significant test for heterogeneity due to the exposure in the primary sample. A third strategy ascertained by exposure status when exposure‐defined subgroup tests were significant in the primary sample. The second strategy reduced the number of false positive linkage signals identified through exposure subgroup identification (i.e., the third strategy), but in this GAW11 data that contained no qualitative gene×environment interactions, it had poor sensitivity. Power to detect heterogeneity depends on the differences in risk between exposed and unexposed.
Obeticholic acid, a farnesoid X receptor agonist, improves portal hypertension by two distinct pathways in cirrhotic rats
Authors: Verbeke Len , Farre Ricard , Trebicka Jonel , Komuta Mina , Roskams Tania , Klein Sabine , Elst Ingrid Vander , Windmolders Petra , Vanuytsel Tim , Nevens Frederik , Laleman Wim
Published: November 2013

The farnesoid X receptor (FXR) is a nuclear bile acid receptor involved in bile acid homeostasis, hepatic and intestinal inflammation, liver fibrosis, and cardiovascular disease. We studied the effect of short-term treatment with obeticholic acid (INT-747), a potent selective FXR agonist, on intrahepatic hemodynamic dysfunction and signaling pathways in different rat models of cirrhotic portal hypertension (PHT). For this, thioacetamide (TAA)-intoxicated and bile-duct–ligated (BDL) rats were used as models. After gavage of two doses of 30 mg/kg of INT-747 or vehicle within 24 hours, in vivo hemodynamics were assessed. Additionally, we evaluated the direct effect of INT-747 on total intrahepatic vascular resistance (IHVR) and intrahepatic vascular tone (endothelial dysfunction and hyperresponsiveness to methoxamine) by means of an in situ liver perfusion system and on hepatic stellate cell contraction in vitro. FXR expression and involved intrahepatic vasoactive pathways (e.g., endothelial nitric oxide synthase [eNOS], Rho-kinase, and dimethylarginine dimethylaminohydrolase [DDAH]) were analyzed by immunohistochemistry, reverse-transcriptase polymerase chain reaction, or western blotting. In both cirrhotic models, FXR expression was decreased. Treatment with INT-747 in TAA and BDL reactivated the FXR downstream signaling pathway and decreased portal pressure by lowering total IHVR without deleterious systemic hypotension. In the perfused TAA and BDL cirrhotic liver, INT-747 improved endothelial vasorelaxation capacity, but not hyperresponsiveness. In both groups, this was associated with an increased eNOS activity, which, in TAA, related to down-regulation of Rho-kinase and in BDL to up-regulation of DDAH-2. Conclusion: FXR agonist INT-747 improves PHT in two different rat models of cirrhosis by decreasing IHVR. This hemodynamic effect relates to increased intrahepatic eNOS activity by pathways that differ depending on the etiology of cirrhosis. (Hepatology 2014;59:2286–2298)
MicroRNA-26a Suppresses Angiogenesis in Human Hepatocellular Carcinoma by Targeting Hepatocyte Growth Factor-cMet Pathway
Authors: Yang Xin , Zhang Xiao-Fei , Lu Xu , Jia Hu-Liang , Liang Lei , Dong Qiong-Zhu , Ye Qing-Hai , Qin Lun-Xiu
Published: November 2013

MicroRNA (miR)-26a can suppress tumor growth and metastasis of hepatocellular carcinoma (HCC). Since angiogenesis is important for tumor growth and metastasis, we investigated the possible roles of miR-26a in tumor angiogenesis. Down-regulation of miR-26a was found to correlate with an increased angiogenic potential of HCC. Through gain- and loss-of-function studies, miR-26a was demonstrated to significantly inhibit vascular endothelial growth factor A (VEGFA) expression in HCC cells and then suppress the promoting effects of HCC cells on

in vitro

proliferation, migration, and capillary tube formation of endothelial cells, as well as

in vivo

tumor angiogenesis of HCC. Hepatocyte growth factor (HGF) was identified as a target of miR-26a. HGF simulation antagonized the effects induced by miR-26a up-regulation. In contrast, silencing HGF induced similar effects to miR-26a. We further found that miR-26a exerted its antiangiogenesis function, at least in part, by inhibiting HGF-hepatocyte growth factor receptor (cMet) and its downstream signaling pathway, in turn, suppressing VEGFA production in HCC cells and impairing VEGFR2-signaling in endothelial cells. HCC patients who had high miR-26a, low HGF, low VEGFA, or low microvessel density (MVD) in tumor tissues had a better prognosis with longer overall survival (OS) and time to recurrence (TTR). In multivariate analysis, miR-26a, or in combination with HGF, was demonstrated to be an independent prognostic indicator for OS and TTR of HCC patients.

Conclusion :

miR-26a could suppress tumor angiogenesis of HCC through HGF-cMet signaling, and it is a new hopeful therapeutic target and prognostic marker for HCC. (Hepatology 2014;59:1874–1885)
Reduced Adiponectin Signaling Due to Weight Gain Results in Nonalcoholic Steatohepatitis Through Impaired Mitochondrial Biogenesis
Authors: Handa Priya , Maliken Bryan D. , Nelson James E. , Morgan-Stevenson Vicki , Messner Donald J. , Dhillon Barjinderjit K. , Klintworth Heather M. , Beauchamp Mary , Yeh Matthew M. , Elfers Clinton T. , Roth Christian L. , Kowdley Kris V.
Published: November 2013

Obesity and adiponectin depletion have been associated with the occurrence of nonalcoholic fatty liver disease (NAFLD). The goal of this study was to identify the relationship between weight gain, adiponectin signaling, and development of nonalcoholic steatohepatitis (NASH) in an obese, diabetic mouse model. Leptin-receptor deficient (Lepr

db/db

) and C57BL/6 mice were administered a diet high in unsaturated fat (HF) (61%) or normal chow for 5 or 10 weeks. Liver histology was evaluated using steatosis, inflammation, and ballooning scores. Serum, adipose tissue, and liver were analyzed for changes in metabolic parameters, messenger RNA (mRNA), and protein levels. Lepr

db/db

HF mice developed marked obesity, hepatic steatosis, and more than 50% progressed to NASH at each timepoint. Serum adiponectin level demonstrated a strong inverse relationship with body mass (

r

= −0.82;

P

< 0.0001) and adiponectin level was an independent predictor of NASH (13.6 μg/mL;

P

< 0.05; area under the receiver operating curve (AUROC) = 0.84). White adipose tissue of NASH mice was characterized by increased expression of genes linked to oxidative stress, macrophage infiltration, reduced adiponectin, and impaired lipid metabolism. HF lepr

db/db

NASH mice exhibited diminished hepatic adiponectin signaling evidenced by reduced levels of adiponectin receptor-2, inactivation of adenosine monophosphate activated protein kinase (AMPK), and decreased expression of genes involved in mitochondrial biogenesis and β-oxidation (

Cox4, Nrf1, Pgc1α, Pgc1β

and

Tfam

). In contrast, recombinant adiponectin administration up-regulated the expression of mitochondrial genes in AML-12 hepatocytes, with or without lipid-loading.

Conclusion :

Lepr

db/db

mice fed a diet high in unsaturated fat develop weight gain and NASH through adiponectin depletion, which is associated with adipose tissue inflammation and hepatic mitochondrial dysfunction. We propose that this murine model of NASH may provide novel insights into the mechanism for development of human NASH. (Hepatology 2014;60:133–145)
Numerical Investigation of Nanofluid Mixed‐Convection Flow in the Entrance Region of a Vertical Channel Partially Filled with Porous Medium
Authors: Hajipour Mastaneh , Dehkordi Asghar Molaei , Jamshidi Saeid
Published: November 2013

In this article, transient two‐dimensional mixed convection of nanofluids in the entrance region of a vertical channel has been studied carefully. The geometry under consideration consisted of a parallel‐plate channel partly filled with a porous medium with a constant wall temperature. In the free flow region, the two‐dimensional flow field has been governed by the Navier–Stokes equations. The general formulation of the momentum equations accounting for the inertial and the viscous effects in the presence of a porous medium has been used. Viscous dissipation effects have also been incorporated in the thermal energy equation. Effects of Brownian diffusion and thermophoresis have also been included for nanoparticles in the nanofluid. The governing equations have been given in terms of the stream function‐vorticity formulation and have been non‐dimensionalized and then solved numerically subject to appropriate boundary conditions. The characteristics of the flow and temperature fields have been presented in the terms of mixed‐convection parameter (GR), Brinkman number (Br), Darcy number (Da), Lewis number (Le), and other important parameters. © 2013 Wiley Periodicals, Inc. Heat Trans Asian Res, 43(7): 607–627, 2014; Published online 21 November 2013 in Wiley Online Library (wileyonlinelibrary.com/journal/htj). DOI 10.1002/htj.21099
The Study of Gel Formation and Flocculation in Aqueous Clay Dispersions by Optical and Rheological Methods
Authors: Neumann Barbara S. , Sansom K. G.
Published: November 2013

Optical and Theological methods have been used to study the gelling and flocculation of aqueous dispersions of a synthetic hectorite‐like clay, Laponite CP, on the addition of electrolytes or water miscible organic solvents. There is a positive correlation between the yield value and turbidity when the dispersions are flocculated with electrolyte. Addition of polar solvent, however, shows no such correlation, only a sudden change from very clear to very cloudy dispersion, while the yield value increases gradually until gross flocculation takes place. It is suggested that two different flocculation mechanisms are being observed.
Quartz Dissolution as Influenced by pH and the Presence of a Disturbed Surface Layer
Authors: Henderson J.H. , Syers J. K. , Jackson M. L.
Published: November 2013

Quartz particles (10 to 2 microns in diameter, produced by grinding) released 45 ppm of SiO2 to a buffer solution of pH 7 during a 48 hr period. The grinding of quartz particles produced a disturbed surface layer with solubility properties intermediate between crystalline quartz (6 ppm SiO2) and amorphous silica (120 ppm SiO2). Removal of the disturbed layer by treatment with 1N HF lowered the SiO2 dissolution from 45 to 3 ppm. Use of 12N HF decreased the amount of SiO2 dissolved to 2 ppm, a result found to coincide with a preferential dissolution of the finer quartz particles in addition to the removal of the disturbed surface layer. The rate of dissolution of SiO2 from quartz particles, subsequent to treatment with 1N HF, increased with decrease in particle size, from 1 to 3 ppm for quartz particles 50 to 20 microns in diameter to 30 to 44 ppm for particles 2 to 0.2 microns in diameter, during each of three consecutive 14‐day extractions with pH 7 buffer solution. The amount of SiO2 dissolved from quartz in buffer solutions increased in the pH range of 4 to 10, from 0.6 ppm of SiO2 at pH 4 to 19 ppm at pH 10 during a 14‐day period of extraction from quartz particles, 10 to 2 microns in diameter. Quartz particles, subsequent to the removal of the disturbed surface layer, removed SiO2 from pH 4 and pH 8 buffer solutions prepared with more SiO2 in solution than would be released from quartz in the respective solution.
An Optical‐Transmission Study of the Interaction Between Montmorillonite and Humic Acids
Authors: Narkis N. , Rebhun M. , Lahav N. , Banin A.
Published: November 2013

The interaction between montmorillonite and kaolinite clay minerals and humic acid (HA) was studied in suspensions by absorbance measurements. Changes in absorbance as a result of the interaction were interpreted as an indication of changes in the size of clay tactoids. Na‐humate caused dissociation of montmorillonite tactoids in suspension. Drying‐wetting cycles increased the effect of Na‐humate and resulted in tactoids similar in their size to those of the Li‐saturated montmorillonite. Na‐humate had no effect on the absorbance of kaolinite suspensions.
N‐n‐Alkylpyridinium Derivatives of Mica‐Type Layer Silicates
Authors: Lagaly G. , Stange H. , Taramasso M. , Weiss Armin
Published: November 2013

This paper deals with the cation exchange of N‐n‐alkylpyridinium ions magnified image against inorganic ions in mica type layer silicates. The arrangements of these ions in the interlayer space is derived from basal spacing measurements.
Methylene Blue Absorption by Montmorillonites. Determinations of Surface Areas and Exchange Capacities with Different Initial Cation Saturations (Clay‐Organic Studies XIX)
Authors: Brindley G. W. , Thompson T. D.
Published: November 2013

Absorption isotherms have been determined for methylene blue absorbed from aqueous solutions on montmorillonites saturated with various cations. Surface areas are determined from observations of the amount of methylene blue absorbed on the clay required to produce optimum flocculation; this condition corresponds to an effective coverage of the surfaces with methylene blue ions. Cation exchange capacities are determined from saturation absorptions. With Li‐ and Na‐saturated clays, the surface areas are approximately 750 m2/g and the exchange capacities agree with values obtained by titration techniques. With K‐montmorillonites, values about 15% smaller are obtained and this is probably due to a small fraction of the clay not expanding beyond about 15Å in water. With M2+‐montmorillonites, a marked difference in behavior is observed between a clay from Wyoming and one from Texas. The Wyoming clay gives much smaller effective flocculation areas and clearly defined saturation absorptions are not obtained. These results are attributed to relatively large particle sizes, so that external surfaces are covered when internal surfaces are only partially covered, and ultimate saturation is hindered by the large particles. With finer particles, the Texas clay gives flocculation areas nearer to those obtained with Li‐ and Na‐clays and the apparent exchange capacities also are nearer to those obtained for the monovalent ion clays. A limitation on surface area measurements for montmorillonites with exchange capacities less than about 100 meq/100 g is discussed.
The Occurrence of Fatty Acids in Fulvic Acid, A Soil Humic Fraction
Authors: Schnitzer M. , Ogner G.
Published: November 2013

Normal fatty acids ranging from C14 to C36 were found to account for a maximal 0.10% of the dry ash‐free weight of a water soluble soil fulvic acid. Only 10.0% of the total fatty acids could be extracted by organic solvents from untreated fulvic acid. The remaining 90.0% was extractable only after methylation of the fulvic acid and adsorption on neutral aluminum oxide. While the nature of the molecular forces that hold the fatty acids to the fulvic acid is still a matter of conjecture, evidence was obtained that reduction of hydrogen bonding by methylation was related to the release of fatty acids by the fulvic acid.

Ninety‐five percent of the acids that were isolated were saturated, the remaining 5.0% were unsaturated and branched‐cyclic. The C24 acid was the major component. The overall C‐even to C‐odd carbon atom ratio for all acids was 2.3. The results suggested two different origins for the fatty acids: the C14 to C26 acids may be of microbiological origin, whereas the C27 to C36 acids may have arisen from plants.

Weight distribution plots of fatty acids and n‐alkanes extracted from the fulvic acid showed an inverse concentration relationship between the two components with identical carbon numbers.

The data reported herein suggest that fulvic acid may act as a vehicle for the mobilization, transport and immobilization of water‐insoluble organic compounds—some of which may be serious pollutants—in an aquatic environment.
Debrominative Phosphorylation
Authors: Granoth I. , Kalir A. , Pelah Z. , Bergmann E. D.
Published: November 2013

The reaction of o‐ and p‐brominated diphenyl sulfides with phosphorus trichloride in the presence of aluminium chloride has been investigated. After hydrolysis, the reaction yields p‐substituted arylthiobenzenephosphonic acids and bromide ion. Similar results are obtained with brominated diphenyl ethers. A mechanism for this “debrominative phosphorylation”, involving a stabilized σ‐complex 8, is suggested on the strength of chemical evidence.
Three‐Chromophore Compounds I. Reductive Transformations of the 3,5‐diaryl‐2‐cyclohexen‐1‐ones
Authors: Meyer A. Y. , Schlesinger J.
Published: November 2013

The preparation of three 3,5‐diarylcyclohexanones by rhodiumchlorotris(triphenyl‐phosphine)—catalyzed reduction of the parent olefines (IIa—IIc) is described. Other reducing agents produced several intermediate products of the total hydrogenolysis.
Vibrational Spectra and Thermodynamic Functions of the Three Isomeric Methoxyphenols
Authors: Verma V. N. , Nair K. P. R. , Rai D. K.
Published: November 2013

Infrared absorption spectra in the range of 250‐4000 cm−1 of the three isomeric methoxyphenols are reported. The para methoxyphenol is in the solid phase at room temperature and its spectrum has been investigated in the range of 700‐4000 cm−1 in chloroform solution in addition to the spectrum recorded for its nujol mull. Under the usual approximation of the two substituent groups taken as point masses the observed bands have been assigned to different modes of vibration. These assignments have been used to calculate the molar thermodynamic functions for these compounds.
Electrocatalytic Oxidation of Amines on Platinum Electrodes. Part III. Oxidation Of Ethylenediamine Via Higher Oxidation States of Nickel
Authors: Fried I. , Meyerstein D.
Published: November 2013

The voltammetric behaviour of aqueous nickel ethylenediamine solutions has been studied. Electrocatalytic oxidation waves were obtained which are attributed to the formation of trivalent and possibly also tetravalent nickel ethylenediamine complexes as intermediates. The mechanism of the electrocatalytic process is discussed.
ESR Study of Cerium (IV) Oxide in Vacuum Air and Hydrogen
Authors: Steinberg M.
Published: November 2013

Cerium (IV) oxide prepared at high temperatures in air shows ESR absorption signals. The oxide prepared at low temperatures shows very diffuse signals. Heating the oxide in vacuum at 1000° or in hydrogen at 298° results in a reduction of the intensity of the signal. A theory was developed to show that the ESR signal is obtained from the quasi free electron in non‐stoichiometric ceria.
Thiohydrolysis of 6‐Methylthio‐8‐Azapurines (7‐Methylthio‐1,2,3,4,6‐Penta‐Azaindenes) Bearing a Methyl Substituent in the Triazole Ring
Authors: Bergmann F. , Rashi M. , Reichman U. , Neiman Z.
Published: November 2013

In 8‐azapurines, the 1,2,3‐triazole ring can assume three tautomeric forms. The corresponding 7‐, 8‐ and 9‐ methy1‐6‐methylthio derivatives all underwent rapid thiohydrolysis to the respective 6‐thio‐8‐azapurines, when treated with ammonium sulfide at room temperature. The high reactivity of the 8‐methyl derivative was anticipated on the basis of its o‐quinonoid structure. However, thiohydrolysis of 7‐ and 9‐ methyl‐6‐methylthio‐8‐ azapurine is unexpected and contrasts sharply with the refractoriness of 7‐ and 9‐ methyl‐6‐methylthiopurine.
Synthesis of Fluoro‐Derivatives of the Higher Natural Sterols
Authors: Ikan R. , Klein P.
Published: November 2013

The preparation of several 3β‐fluoro‐ and 6β‐fluoro‐3β, 5α‐dihydroxysterols and their NMR spectra is described.
Nephelometric Measurements by Use of a Spectrofluorometer. Part I: (A) Determination of Sulphate; and (B) Determination of Calcium
Authors: Gonen L. , Cogan E.
Published: November 2013

An approach to quantitative nephelometric measurements using a spectrofluorometer is presented. The measurements are performed with the aid of a monochromatic filter, which is transparent for the line 546 nm and by adjusting the monochromator for the same wavelength. The method was applied for the determination of micro amounts of: (1) sulphate as barium sulphate in colorless or colored aqueous solutions, in phosphoric acid, in the presence of large amounts of iron and in ores; is also suitable for determination of total inorganic sulfur after oxidation to sulphate and in organics after combustion; (2) calcium as calcium naphthalhydroxamate in aqueous and phosphoric acid solutions; and (3) calcium in the presence of large amounts of magnesium. The proposed technique has proved useful for quantitative nephelometric determinations in colored solutions. The high sensitivity also permits the use of micro samples.
Reactions of ReF7 and ReOF5 with Fluoride Ion Donors
Authors: Selig H. , Karpas Z.
Published: November 2013

Reactions of ReF7 and ReOF5 with NOF and NO2 F yielded the compounds NO+ReF8−, NO2+ReF8−, NO+ReOF6− and NO2+ReOF6−. Raman spectra of the solids and NMR spectra of solutions in anhydrous HF show that the complexes are ionic and give tentative indications that ReF8− has D4d symmetry and ReOF6− has C5v symmetry.
Some Derivatives of Glycyrrhetic Acid
Authors: Rozen S. , Shahak I. , Bergmann E. D.
Published: November 2013

Substituted amides of glycyrrhetic acid have been prepared. The substituents were chosen for their solubilizing effect and potential biological interest.
Synthesis of Some Polymeric Dyes
Authors: Tahan M. , Perez D. , Zilkha A.
Published: November 2013

Polymeric dyes derived from 4‐vinyl phthalic acid and 2,2′‐divinyl benzidine were prepared. Diethyl 4‐vinyl phthalate was synthesized as follows: The Diels‐Alder reaction between 2‐ethyl butadiene and dichloromaleic anhydride led to the formation of 4‐ethyl phthalic anhydride which was esterified, α‐brominated in the side chain by NBS, and dehydro‐brominated by heat. The resulting monomer was polymerized and polydiethyl 4‐vinyl phthalate was reacted with phenol and resorcinol to yield “polyphenolphthalein” and “polyfluorescein” respectively. 2,2′‐Divinyl benzidine was diazotized and coupled with naphthionic acid, anthranilic acid and N,N′‐dimethylaniline respectively, but the resulting vinylic dyes did not polymerize due to steric reasons. However, polymeric dyes were obtained by homopolymerizing, or copolymerizing, 2,2′‐divinyl benzidine with vinyl monomers, diazotizing the corresponding soluble polymers and coupling them with the above reagents. All the polymeric dyes exhibited indicator functions, changing their colour in basic or acidic media.
The Use of Amberlyst Ion‐Exchanger in the Picolyl Ester Method of Peptide Synthesis
Authors: Burton J. , Young G. T.
Published: November 2013

The use of Amberlyst‐15 ion‐exchanger (as the 3‐bromopyridinium salt) for the separation of coupling product in the picolyl ester method of peptide synthesis is exemplified by a description of the synthesis of N‐butoxycarbonyl‐O‐benzyl‐L‐seryl‐S‐benzylthiomethyl‐L‐cysteinylglycyl‐L‐phenylalanine 4‐picolyl ester, in 76.5% overall yield, from phenylalanine 4‐picolyl ester dihydrobromide.
Synthetic Peptides Related to Horse Heart Cytochrome C V. Peptides Corresponding to Positions 94–104
Authors: Wolman Y. , Klausner Y. S.
Published: November 2013

Synthesis is described of a series of peptide derivatives which corresponds to positions 94‐104 in the primary structure of horse heart Cytochrome C. The preparations of the C terminus undecapeptide derivative α ‐benzyl‐L‐leucyl‐L‐isoleucyl‐L‐alanyl‐O‐benzyl‐L‐tyrosyl‐L‐leucyl‐Nϵ ‐trifluoroacetyl‐L‐lysyl‐Nϵ‐trifluoroacetyl‐L‐Lysyl‐L‐alanyl‐L‐threonyl‐L‐asparaginyl‐γ‐benzyl‐L‐glutamate trifluoroacetate and the C terminus nonapeptide L‐alanyl‐L‐tyrosyl‐L‐leucyl‐L‐lysyl‐L‐lysyl‐L‐alanyl‐L‐threonyl‐L‐asparaginyl‐L‐glutamic acid is described.
N‐Alkylation During the Removal of a Carbamate‐Type Protecting Group
Authors: Sheradsky T. , Salemnick G. , Frankel M.
Published: November 2013

Acidolysis of 2‐(p‐biphenylyl)isopropyl N‐(5‐nitro‐2‐pyridyloxy)carbamate (IV) resulted in loss of carbon dioxide and formation of N‐2‐(p‐biphenylyl)isopropyl‐O‐(5‐nitro‐2‐pyridyl) hydroxylamine (V). The mechanism of this unusual reaction is discussed.
Reactive Species Mutually Isolated on Insoluble Polymeric Carriers. II. The Alkylation of Esters
Authors: Kraus M. A. , Patchornik A.
Published: November 2013

Polymer esters of the type magnified image have been alkylated by the use of trityllithium and an alkyl halide. The sole product obtained was that of monoalkylation. No self condensation occurred due to the immobilizing effect of the polymeric carrier.
Palladium Catalysed Reaction of Myrcene with Acetic Acid and Phenol
Authors: Watanabe S. , Suga K. , Hijikata K.
Published: November 2013

This paper concerns the reaction of myrcene, 7‐methyl‐3‐methylene‐1,6‐octadiene, with acetic acid‐sodium acetate and phenol‐sodium phenoxide in the presence of a variety of palladium‐catalysts under various conditions. The reaction of myrcene with acetic acid catalysed by palladous chloride‐triphenyl phosphine in benzene under nitrogen gave a mixture of linalylacetate (I), 2‐acetoxy‐3‐methylene‐7‐methyl‐6‐octene (II), 3‐acetoxymethyl‐7‐methyl‐2,6‐octadiene (III), nerylacetate (IV) and geranylacetate (V) in yield of 15%. The analogous reaction catalysed by palladium‐cupric acetate under oxygen gave the similar acetates mixture in yield of 21%. The reaction of myrcene with phenol catalysed palladous chloride‐benzonitrile complex gave a mixture of various terpene ethers and myrcene dimers.
Infrared Spectra and Surface Reactions of HCl, DCl and Cl2 Adsorbed on Germanium
Authors: Lubezky A. , Folman M.
Published: November 2013

Adsorption of HCl, DCl and Cl2 on high surface area germanium films was studied by means of IR absorption spectra. The films were prepared by high temperature evaporation of germanium in a helium atmosphere. On adsorption of HCl and DCl two main absorptions appeared at 460 cm−1 and 408 cm−1 and additional weaker bands at 2050 cm−1 and 2920 cm−1 (with HCl) and at 1313 cm−1 (with DCl). The spectra indicate that both gases undergo dissociation on adsorption. In the case of Cl2 the bands at 460 cm−1 and 408 cm−1 appeared in the spectrum; here again strong evidence exists that dissociative adsorption takes place. Mass spectrometer analysis showed that the desorption product consists mainly of GeCl4.
Preparation and Properties of Tricyclopentadienyl Cerium (IV) Chloride and Bisindenyl Cerium (IV) Dichloride
Authors: Kalsotra B.L. , Multani R.K. , Jain B.D.
Published: November 2013

The reactions of dipyridinium cerium (IV) hexachloride with tetracyclopentadienyl cerium or sodium cyclopentadienide and tetraindenyl cerium or sodium indenide in tetrahydrofuran yield tricyclopentadienyl cerium (IV) chloride and bisindenyl cerium (IV) dichloride. Infrared spectra, thermal stabilities and other characteristics of the compounds have been studied.
Uranium (VI) Complexes of Some Tridentate Schiff Bases
Authors: Mehta R.K. , Gupta R.K. , Singhi V.C.
Published: November 2013

Protonation constants (log KH1 and log KH2) of N‐acetylacetoneanthranilic acid (abbr. H2 AA), N‐salicylideneanthranilic acid (abbr. H2SA) and N, (2‐hydroxy‐1‐naphthalidene) anthranilic acid (abbr. H2 NA), and formation constants of their uranium (VI) complexes have been determined potentiometrically in 50% dioxan (vol/vol) solutions (μ = 0.1 M NaClO4) at 30 ± 0.1°C. The stabilities of these complexes were found to be in the order: UO2+2‐H2NA > UO2+2‐H2SA > UO2+2‐H2AA.
Light Scattering of Montmorillonite in NaCl and Na‐Phosphate Solutions Subjected to Pulsed Electric Fields
Authors: Lahav N. , Raziel S. , Pecht I.
Published: November 2013

Changes in scattered light of fresh and aged sodium montmorillonite, suspended in sodium chloride and phosphate solutions after application of very short and strong electrical fields, was studied. Montmorillonite suspensions behave like polydispersed systems. Results of phosphate treated montmorillonite were compared with phosphate‐free montmorillonite, in which a flocculation process took place. The range of particle size for the phosphate treated montmorillonite was calculated.
On the Direct Spectrographic Analysis of Steels for Boron
Authors: Schoenfeld Irena
Published: November 2013

The possibility of direct spectrographic analysis for the routine determination of boron in steels in the range 10–150 ppm was investigated. The procedure was worked out that requires no specialized equipment, is rapid and simple, and suitable for routine control analyses when precision is not of prime importance. The method uses DC‐arc excitation of the samples in the form of powder or chips, with LiF added both as buffer and volatilizing agent. The electrodes are deep, with large capacity so that they can hold samples of about 150 mg, as the use of a large sample lowers the detection limit. The analytical line used is BI 2089.6 Å and the spectra are recorded on Ilford Q‐2 plates. One of the results of this work is a correction of the wavelength of the BII 3451 Å line.
Some Calculated Standard Free Energy Changes During Chemical Weathering of Rock‐Forming Silicates
Authors: Yariv S.
Published: November 2013

Standard free energy changes of dissolution and hydrolysis of rock‐forming silicates and those of leaching of soluble cations from the same silicates were computed. Correlation between the sequence of Goldich and the order of changes of standard free energies was observed only in the dissolution process. It seems that chemical weathering is governed mainly by aqueous dissolution.
The Luminescence of Some Luminol Oxidation Products
Authors: Nikokavouras J. , Perry A. , Vassilopoulos G.
Published: November 2013

The oxidation of luminol with t‐butyl hypochlorite and the fluorescence and chemiluminescence of some of the products are herein reported. The fluorescence was studied in the present work as a function of pH and the spectral distribution was then recorded at the pH of maximum fluorescence intensity; the chemiluminescence spectrum was obtained under the conditions of the luminol‐chemiluminescence.
Preparation, IR, UV, NMR, and Mass Spectral Fragmentations of New Substituted Phenoxaphosphinic Acids
Authors: Levy J. B. , Whitehead G.W. , Granoth I.
Published: November 2013

The synthesis and IR, UV, NMR; and mass spectral fragmentations of substituted phenoxaphosphinic acids I – XIV are reported. A diazo method gave I, and the Friedel‐Crafts method II – XIV. Infrared assignments: POH, broad bands, 2600, 2250, and 1650; C‐P, 1490 ‐ 1440; C‐O, 1280 ‐ 1260; P=0, 1190 ‐ 1140; and P‐O, 978 ‐ 974 cm−1. Characteristic bands also occur at 1330 ‐ 1320 and 1230 ‐ 1210 cm−1. The UV spectra possess maxima at 210 ‐ 220 mμ (log ∈ 4.50 ‐ 4.60), 240 ‐ 250 (4.20 ‐ 4.30), and 298 – 304 (3.65 – 3.75). The NMR spectra give τ 7.56 ppm for a 2‐methyl substituent, 7.48 for a 4‐methyl and a quartet at 7.26 and a triplet at 8.71 (J = 7.7 Hz) for a 2‐ethyl. The chemical shifts were virtually unaffected by alkyl or halogen substituents on the other aromatic ring but were shifted upfield by ortho or meta methyl substituents on the same ring. Singlets at τ 7.44 and 7.60 ppm in the spectrum of VIII gave calculated base values of about 7.28 and 7.44 for a 1‐methyl and 3‐methyl, respectively. The mass spectra are greatly influenced by the substituents. All showed loss of PO2H from the molecular ion or in the case of ethyl compounds after CH3· expulsion. CHO or CCIO was then eliminated. The molecular ions of methyl compounds eliminated H2O.
Mass Spectra of Amine Picrates
Authors: Deutsch J. , Sklarz B.
Published: November 2013

The mass spectra of several amine picrates were found to consist of the amine spectrum superimposed on, and hardly disguised by, that of picric acid. The mass spectrum of an amine isolable only as the picrate can thus be obtained.
2‐Azabicyclo [3.2.0] Heptane‐3‐One
Authors: Nativ E. , Rona P.
Published: November 2013

2‐Azabicyclo [3.2.0] heptane‐3‐one was synthesized by the reaction of cyclopentene and chlorosulphonyl isocyanate. The structure of the product was established by its hydrolysis to cis‐2‐amino‐cyclopentanecarboxylic acid.
Absolute Intensities and the Chemical Objectives of Charge Density Studies by Diffraction Methods
Authors: Coppens Philip
Published: November 2013

It is shown that an experimental measurement of the absolute scale is highly desirable for the quantitative measurement of atomic form factors and, more generally, electron distributions in crystals. The experimental scale‐factor measurement on the mineral kernite confirms that atomic orbitals in molecules are contracted relative to isolated‐atom orbitals. Objectives of charge‐density measurements are divided into direct analysis of the charge density and the analysis of derived quantities, such as net atomic charges, dipole moments and the ionic character of bonds.
Organic Carbonates. Part XIII. Separation of Polar and Steric Effects in the Hydrolyses of Substituted Ethylene and Trimethylene Carbonates
Authors: Katzhendler Joshua , Poles L. A. , Sard Shalom
Published: November 2013

The rate constants, the free energies (ΔF#), the energies (ΔH#) and entropies (ΔS#) of activation, and the steric parameter of substituent (Es), for both the acid and the alkaline hydrolyses of four highly branched ethylene carbonates (Ia ‐ d), and 11 trimethylene carbonates (IIa ‐ k) were analysed according to Taft's procedure for a quantitative separation of polar and steric effects of alkyl substituents in the total effect of structure upon reactivity in hydrolysis. Application of Eq. (II) with Σσ* to the most hindered substrates (“α‐axial methyl effect”) (IId ‐ f) and to the moderately hindered substrates (IIa ‐ c) gave well‐separated parallel straight lines for the two groups. Deviations from Eq. (II) were manifested by the rate‐enhanced group of compounds, geminally 2,2‐disubstituted trimethylene carbonates (IIg ‐ k) (“2,2‐gem‐dialkyl effect”), shown to exert a polar “field effect”; the assessment of its substituent constant σF* (= +0.17) is provided by Eq. (III). Analysis of 018 exchange experiments and ΔΔFA# vs ΔΔFB# correlation (Eq. (IV)) show that the acid‐ and base‐catalysed reactions occur in parallel via similar transition states, the attainment of each designating the rate‐determining step in both systems. A value of 0.5 kcal/mole was found for the net steric interaction (ESB ‐ ESA) exerted by an α‐axial methyl substituent on the attacking hydroxide ion in attaining the transition state. It was concluded that in alkaline hydrolysis, the transition states of compounds exhibiting an “α‐axial methyl effect” should closely resemble the tetrahedral intermediate (IX), while the transition states of the 2,2‐gem‐dialkyl series should more closely resemble the ground‐state.