bluuebunny/crossref_metadata_2025 huggingface dataset:
Incorporating larger families in identity‐by‐descent based linkage analysis
Authors: Loesgen Sabine , Scholz Michael , Schmidt Silke , Bickeböller Heike
Published: November 2013

Genome scans for alcoholism susceptibility genes were carried out using identity‐by‐descent‐based statistics for qualitative traits. We compared the results when 1) multipoint information was used for all families, where some had to be truncated, 2) multipoint information was used only for small families while large (untruncated) pedigrees were analyzed with a single‐point approach, and 3) single‐point analysis was used for all pedigrees. Differences between the methods were observed, but neither method could identify regions related to the susceptibility for alcoholism.
Novel tests for marker‐disease association using the collaborative study on the genetics of alcoholism data
Authors: Nielsen Dahlia , Zaykin Dmitri
Published: November 2013

We applied several novel tests for association and linkage in the presence of association to the Genetic Analysis Workshop 11 Problem 1 data set. Our analyses included a Hardy‐Weinberg test for association between a marker and a disease susceptibility locus, a Bayesian transmission/disequilibrium test, and a Bayesian case‐control test. Positive results for each of these methods require the presence of population association between the marker and a disease susceptibility locus.
Haplotype analysis in the collaborative study on the genetics of alcoholism data: Double recombinants
Authors: Petronis Arturas , Kennedy James L. , Paterson Andrew D.
Published: November 2013

The presence of close double recombinants in genotyping data may help identify genotyping errors. Alternatively, putative double recombinants may be associated with genetic mechanisms that may be related to disease. Phase‐known apparent double recombination events were identified in the Collaborative Study on the Genetics of Alcholism data, and compared to the sex‐specific genetic map at each region. A number of double recombinants occurred within a short genetic distance. Also, in some families multiple double recombinants were observed flanking the same genetic marker, both suggesting possible genotyping error. An excess of paternal double recombinants was identified, which is consistent with reports of sex‐specific differential meiotic interference.
Association and linkage analysis of ICD‐10 diagnosis for alcoholism
Authors: Tiwari Hemant K. , Zhu Xiaofeng , Elston Robert C. , Shu Youyi , George Varghese
Published: November 2013

We analyzed the GAW11 data on alcoholism provided by the Collaborative Study on the Genetics of Alcoholism (COGA) using an extension of a new test of linkage and association for quantitative traits developed by George et al. [1999]. This method determines linkage between marker loci and quantitative traits, when allelic association is present between the trait and marker loci, by regressing the disease trait on the parental transmission of the allele of interest. We found no strong evidence of linkage to any markers. However, we found several markers suggestive of possible linkage that may deserve further investigation.
A logistic regression extension of the transmission disequilibrium test for continuous traits: Application to linkage disequilibrium between alcoholism and the candidate genes DRD2 and ADH3
Authors: Waldman Irwin D. , Robinson Byron F. , Rhee Soo Hyun
Published: November 2013

The transmission disequilibrium test (TDT) recently has become a popular method of testing for linkage in the presence of association due to its simplicity and advantages over other within‐family analytic methods. In this paper, we describe a logistic regression extension to the TDT that can be used to test for differences in linkage disequilibrium as a function of one or more continuous and/or categorical explanatory variables. We highlight important features of this method and demonstrate some of its possible uses. We applied these analyses to test for linkage disequilibrium between the dopamine receptor D2 (DRD2) and alcohol dehydrogenase 3 (ADH3) genes and both diagnostic and quantitative indices of alcoholism. Using data from the Collaborative Study on the Genetics of Alcoholism data set, we found evidence suggesting linkage disequilibrium between DRD2 and ADH3 and quantitative indices of alcoholism and correlated phenotypes corresponding to smoking and personality. None of the evidence for linkage disequilibrium varied by sex or age.
Asymptotic power of likelihood‐ratio tests for detecting quantitative trait loci using the COGA data
Authors: Williams Jeff T. , Blangero John
Published: November 2013

We investigated the asymptotic power of the likelihood‐ratio test for detecting linkage to a quantitative trait locus (QTL) using the data set from the Collaborative Study on the Genetics of Alcoholism (COGA). Assuming a total trait heritability of 50% as determined for the COGA Cz P300 phenotype, we determined the minimum QTL heritability required at each point in the genome to achieve 80% power to detect linkage with a lod of 3.0. We find that there are regions of the genome where it is not possible to detect a QTL of any effect with 80% power, and that the overall minimum detectable QTL heritability for the COGA data is 0.35–0.40.
Genome search for alcohol dependence using the weighted pairwise correlation linkage method: Interesting findings on chromosome 4
Authors: Zinn‐Justin Anne , Abel Laurent
Published: November 2013

The nonparametric (model‐free) method of linkage analysis Weighted Pairwise Correlation (WPC) has been proposed by Commenges [1994], and extended to incorporate identity‐by‐descent (IBD) information [Zinn‐Justin and Abel, 1999]. We performed an autosome‐wide scan in the Collaborative Study on the Genetics of Alcoholism data using the WPC‐IBD method, considering two phenotypes related to alcohol dependence defined as residuals of binary traits adjusted for age and sex. Three chromosome 4 markers located in a region of 50 cM spanning from GABRB1 to D4S1651 provided Monte Carlo (MC) p‐values lower than 0.005, confirming the possible influence of β1 GABA receptor and ADH genes in alcoholism. Furthermore, marker D15S642, not far from the ALDH6 gene, provided an MC p‐value of 0.0005 in ethnic groups “White, Hispanic” and “White, non‐Hispanic.”
Disease‐marker associations: Power and heterogeneity in independent population samples
Authors: Bull Shelley B. , Toma Camil , Mirea Lucia
Published: November 2013

We applied generalized transmission disequilibrium testing (TDT) models in combined replicates 1 through 5 from each of four simulated population samples. All analyses were conducted without knowledge of the generating models. To assess power and consistency of results within and between samples, analyses were repeated in all 25 replicates combined and in each replicate. With the exception of sample‐specific findings for locus D, power was generally low to detect linkage in a genome scan or to confirm linkages detected by allele sharing in affected relatives, due to lack of linkage disequilibrium. We proposed likelihood ratio and Wald tests to detect heterogeneity among samples in disease‐marker associations. Pooling data across heterogeneous populations may not improve power of the TDT method.
Improving the power for disease locus detection in affected‐sib‐pair studies by using two‐locus analysis and multiple regression methods
Authors: Cordell Heather J. , Jacobs Kevin B. , Wedig Geoffrey C. , Elston Robert C.
Published: November 2013

In this paper we present a summary of an analysis of the simulated data (Problem 2) for GAW11. We used sib‐pair and affected‐sib‐pair (ASP) methods to evaluate linkage to the mild form of disease at markers across the genome, in data sets of realistic moderate size (containing between 100 and 300 families selected from the simulated replicates). The true ‘answers’ were known in advance. Although in most cases we were successful in detecting linkage to disease in the correct regions, it was often difficult to distinguish these results from false positives elsewhere in the genome. We used two‐locus methods to see whether the significance was improved by simultaneously modeling linkage to two disease loci, and found a modest increase in significance using two‐locus methods in several cases.
Performance of the nonparametric linkage analysis using GENEHUNTER for a complicated genetic disease
Authors: He Qimei , Nemesure Barabara Berger , Mendell Nancy Role
Published: November 2013

The nonparametric linkage (NPL) analysis of the GENEHUNTER program was applied to one set of the simulated data of Problem 2, GAW11. We conducted a straightforward screening of the genome to evaluate the performance of the NPL test, with respect to its ability to detect linkage on specific disease loci. Our findings indicate that disease genes were detected with relatively good power, despite the presence of a complex inheritance pattern. We found that the NPL test varies depending on penetrance rates and gene frequencies, however, we conclude that it is a useful tool for linkage analysis.
Hepatocellular carcinoma screening in patients with compensated hepatitis C virus (HCV)-related cirrhosis aware of their HCV status improves survival: A modeling approach
Authors: Mourad Abbas , Deuffic-Burban Sylvie , Ganne-Carrié Nathalie , Renaut-Vantroys Thibaud , Rosa Isabelle , Bouvier Anne-Marie , Launoy Guy , Cattan Stephane , Louvet Alexandre , Dharancy Sébastien , Trinchet Jean-Claude , Yazdanpanah Yazdan , Mathurin Philippe
Published: November 2013

Because of the ongoing debate on the benefit of ultrasound (US) screening for hepatocellular carcinoma (HCC), we assessed the impact of screening on hepatitis C virus (HCV)-related compensated cirrhosis patients aware of their HCV status. A Markov model simulated progression from HCC diagnosis to death in 700 patients with HCV-related compensated cirrhosis aware of their HCV status to estimate life expectancy (LE) and cumulative death at 5 years. Five scenarios were compared: S1, no screening; S2, screening by currently existing practices (57% access and effectiveness leading to the diagnosis of 42% at Barcelona Clinic Liver Cancer stage [BCLC-0/A]); S3, S2 with increased access (97%); S4, S2 with an efficacy of screening close to that achieved in a randomized controlled trial leading to the diagnosis of 87% of patients at stage BCLC-0/A; S5, S3+S4. The analysis was corrected for lead-time bias. Currently existing practices of HCC screening increased LE by 11 months and reduced HCC mortality at 5 years by 6% compared to no screening (P = 0.0013). Compared to current screening practices, we found that: 1) increasing the rate of access to screening would increase LE by 7 months and reduce HCC mortality at 5 years by 5% (P = 0.045); 2) optimal screening would increase LE by 14 months and reduce HCC mortality at 5 years by 9% (P = 0.0002); 3) the combination of an increased rate of access and optimal effectiveness of HCC screening would increase LE by 31 months and decrease HCC mortality at 5 years by 20% (P < 0.0001). Conclusion: The present study shows that US screening for HCC in patients with compensated HCV-related cirrhosis aware of their HCV status improves survival and emphasizes the crucial role of screening effectiveness. (HEPATOLOGY 2014;59:1471-1481)
Adherence to the Mediterranean diet and gastric cancer risk in Italy
Authors: Praud Delphine , Bertuccio Paola , Bosetti Cristina , Turati Federica , Ferraroni Monica , La Vecchia Carlo
Published: November 2013

We investigated gastric cancer risk in relation to the adherence to the Mediterranean diet using data from two case–control studies conducted in Italy between 1985 and 2007, including 999 incidents, histologically confirmed gastric cancers and 2,628 controls admitted to hospital for acute non‐neoplastic diseases. Adherence to the Mediterranean diet was assessed using the Mediterranean Diet Score (MDS) based on nine of the major characteristics of the Mediterranean diet in the overall dataset. The Mediterranean Dietary Pattern adherence index (MDP) and the Mediterranean Adequacy Index (MAI) were considered in the second study only. We estimated odds ratios (OR) and corresponding 95% confidence intervals (CI) of gastric cancer for categories of the three scores using multiple logistic regression models. We found a reduced risk of gastric cancer for increasing levels of the MDS: as compared to subjects in the lowest category of the MDS, the ORs were 0.78, 0.61 and 0.57 in subsequent levels of MDS, with a significant trend in risk. Risk estimates were consistent across strata of age, sex, education, smoking, body mass index, and family history of gastric cancer. We also observed a decreased risk of gastric cancer for the highest versus the lowest quintile for MDP and MAI, with OR of 0.58 and 0.71, respectively. Our study provides convincing evidence of a beneficial role of the Mediterranean diet on gastric cancer.
Chemical Analyses of Dead Sea and Jordan River Water, 1778–1830
Authors: Nissenbaum A.
Published: November 2013

The first analysis of Dead Sea water was done in 1778. The progress in the science of analytical chemistry is reflected in the improved procedures used for analysis of Dead Sea water. The first analysis by Macquer, Lavoisier and Sage (1781) noted most of the unusual chemical properties of the lake. The earliest search for life in the Dead Sea was made by Gay Lussac in 1817 while trace element analysis goes back to 1827. Some of the early investigators suggested that most of the salt content is contributed by the Jordan River, accompanied by precipitation of CaCO3 and CaSO4. This hypothesis is now accepted by many investigators.
Conductance Studies of Na‐Bentonite‐Water Systems
Authors: Jørgensen P. , Low P. F.
Published: November 2013

Clay (Na‐Wyoming bentonite) was mixed with water to form sols and gels having clay concentrations ranging from 0 to 60 gm clay per 100 gm. The specific conductances of these sols and gels were measured at several temperatures in the range 20° to 25°C. From the results, the weight conductances and apparent activation energies for conductance were calculated. Then these quantities were plotted against clay concentration. Similar plots were made using the data of other investigators. It was found that the weight conductance decreased markedly with clay concentration between 0 and about 0.5 gm of clay per 100 ml, then rose to a maximum at 10–20 gm clay per 100 ml, and fell steadily thereafter. Whereas, the apparent activation energy increased continuously over the same range of clay concentrations. These observations were explained on the basis of equations that were derived in the theoretical part of the paper.
The Effect of Lithium on the Cation Exchange Behaviour of Crystalline and Amorphous Clays
Authors: Eckstein Yona , Yaalon D. H. , Yariv S.
Published: November 2013

The amount of cations displaced by LiCl—LiOAc from standard clay minerals and soil clays was dependent on the concentration and pH of the replacing solution. Lithium was more effective in replacing monovalent ions than ammonium. Appreciable quantities of Li were adsorbed by replacement on the broken bonds of the clay surfaces, especially in the amorphous clays. Certain montmorillonite clays fixed some of the sorbed Li. In general, the cation exchange behaviour was highly dependent on the structure of the clay mineral and the nature of its surface. The sum of displaced cations can be taken as representing the exchange capacity of the clay at the experimental conditions, while the amount of retained Li provides supplemental information on the nature of the bonds.
The Application of Alkali Dissolution Techniques in the Study of Aluminium Hydroxides and Oxyhydroxides
Authors: Storgaard Jørgensen S. , Mitchell B.D.
Published: November 2013

The effect of treatment with 5% sodium carbonate solution on aluminium hydroxides and oxyhydroxides likely to occur in soils has been investigated. Ultrasonic pretreatment, sample to solution ratio and temperature were factors studied. It is shown that particle size and degree of order of the sample influence the amount of alumina dissolved in 5% sodium carbonate solution in a fixed time; it is apparent, however, that both dissolution rate and solubility can be determining factors. Consequently, extraction with alkali at a low temperature and with a low solid: solution ratio is desirable for the preferential dissolution of poorly‐ordered aluminous material from soil clays.
Mineralogical Analysis of Clays in Soils Developed from Basalts in Australia
Authors: Briner G.P. , Jackson M.L.
Published: November 2013

Clay mineralogical analyses were made of red soils and black soils developed from southern Victoria, Australia. The clays of the black soils are dominantly montmorillonite (39%) and vermiculite (16%) but have an average siliceous allophane content of 17%. The clays of the red soils are dominantly kaolinite and halloysite (26%) and chlorite (30%) but have an average halloysitic allophane content of 21%. Two to eight per cent of mica and quartz occur in both. A longer period of eolian dust accumulation and concurrent weathering and soil development have occurred in the red soils than in the black soils since the last cycle of geological erosion. A simple chemical method was used for the estimation of allophane (amorphous alumina, silica, and iron oxide with water) and kaolinite plus halloysite. After selective dissolution of allophane, free Al(OH)3, and amorphous SiO2 during 2.5 min of boiling in 0.5N KOH solution, the residue is subjected to heat treatment at 550°C to dehydroxylate the kaolinite and halloysite. This is followed by another 2.5 min dissolution treatment in 0.5N KOH and a further deferration with dithionite. Some iron‐rich montmorillonitesaponite (smectite) and vermiculite are also dehydroxylated on heating and subsequently are partially dissolved in the KOH. The kaolinite and halloysite constituents were then calculated.
Biological Productivity in the Dead Sea Part II. Evidence for Phosphatidyl Glycerophosphate Lipid in Sediment
Authors: Kaplan I.R. , Baedecker M.J.
Published: November 2013

Reducing surface sediment from a depth of 300 m in the Dead Sea was found to contain phytanic acid (520 μg/Kg), dihydrogen phytol (800 μg/Kg) and phytane (17 μg/Kg). An investigation revealed that glycerol phytanyldiether could be isolated from the sediment by hydrolysis of a lipid soluble fraction. The phytanyldiether is probably derived from the phosphatidyl glycerophosphate lipid, which has been demonstrated by Kates and co‐workers to be the dominant lipid present in red halophilic bacteria. Comparison of results by analysis of Halobacterium cutirubrum, using the same analytical procedure as was used for the sediment investigation, confirmed the authenticity of the lipid characterization. In view of this finding, it is suggested that phytane in the Dead Sea sediment has been derived from this lipid and that long‐chain isoprenoid hydrocarbons in some ancient environments may have had a similar origin.
The Mass Spectra of Phenoxaphosphine Derivatives
Authors: Granoth I. , Kalir A. , Pelah Z. , Bergmann E.D.
Published: November 2013

Derivatives of phenoxaphosphine (I) do not behave under electron impact like diphenyl ethers: they do not lose CO, while loss of CHO was observed. The first step is the breakage of the P‐R bond, followed by elimination of the phosphorus atom or—after rearrangement — a PO group. Methyl groups are either eliminated or cause the formation of tropylium structures. In halogen derivatives of I, not only the elimination of CHO, but also of COHal has been observed. In phenyl‐di‐(o‐phenoxyphenyl)‐phosphine (XXVI), a C‐O bond is broken in preference to a C‐P bond, and the 10,10‐diphenylphenoxaphosphonium ion (XXVIII) is formed.
Photochemistry of the Ferrocyanide Ion in Aqueous Solution: Hydrated Electron Formation and Aquation
Authors: Stein G.
Published: November 2013

Light absorption by the Fe(CN−)4−6 ion in aqueous solution at selected wavelengths between 214 and 313 nm results in the formation of excited states which yield the reaction sequence:

with φe, the quantum yield, decreasing from 0.9 at the lowest to 0.1 at the highest wavelength. At and above 337.1 nm φe = 0. The role of charge transfer to solvent (CTTS) intermediates in this process is demonstrated. Photoaquation according to magnified image is found to have very low, possibly zero quantum yield in this region. The role of acid‐base equilibria, e. g. magnified image and of the protonated species, in the photochemistry of cyanoferrate (II) species is discussed.
The Direct Synthesis of β‐hydroxy‐acids by Lithium Naphthalene and Acetic Acid
Authors: Watanabe S. , Suga K. , Fujita T. , Fujiyoshi K.
Published: November 2013

Lithium naphthalene reacts with acetic acid to give α‐anion of lithium acetate. The reaction of this anion with various ketones gives the corresponding β‐hydroxy‐acids in good yield.
Kinetic and Adsorption Effects in the Polarographic Reduction of Chlorate Catalyzed by Molybdenum‐Tungsten Mixtures
Authors: Hobara I.
Published: November 2013

The polarographic reduction of chlorate catalyzed by molybdenum‐tungsten mixtures is investigated. The reduction currents are limited by the rate of the chemical reactions in the bulk of the solution. The reactants are adsorbed on the mercury drop. Their rate of adsorption is fast compared to the rate of the chemical reactions.
Oxydoreduction and Complex Formation Between Fe3+ Ions and Acetylacetonedioxime
Authors: Adato I. , Ben‐Bassat A. H. I. , Sarel S.
Published: November 2013

The reactions between Fe3+ ions and acetylacetonedioxime (AADO) have been studied by potentiometric, polarographic and spectrophotometric methods. Two Fe3+ ions are reduced in aqueous solution by one AADO molecule to give Fe2+ ions and the oxidized form of AADO (NPO = AADO‐2e = 2‐nitrosopent‐2‐en‐4‐one oxime). NPO forms a water soluble, red coloured complex with Fe (III). The synthesis of bis (2‐nitrosopent‐2‐en‐4‐one oximato) Fe (III) complex is described. The elemental analysis of the solid complex is consistent with the composition FeO (NPO)2 (OH). The IR, EPR and Mössbauer spectra of the complex are presented and the bonding properties of the coordination environment of Fe (III) is discussed. A mechanism for the oxydoreduction and complexation reactions for the Fe3+ ‐AADO system is proposed and its kinetic parameters are: kox.red. = 1.72 × 10 −1 min−1, kcompl. = 5.13 l0−2min−1.
Reactions of Dimethyl Benzoylphosphonate
Authors: Shahak I. , Peretz J.
Published: November 2013

Reactions of dimethyl benzoylphosphonate (I) with various nucleophiles are described. The ester can serve simply as a useful benzoylation agent or it can undergo addition reactions to give substituted α‐hydroxybenzylphosphonates. Its keto‐group can be reduced to hydroxyl and can participate in the Wittig‐Horner reaction. By the action of I with hydroxylamine in the presence of sodium formate, benzonitrile is obtained.
The Effect of Buffered Sodium Dithionite Solution and Ultrasonic Agitation on Soil Clays
Authors: Mitchell B. D. , Smith B. F. L. , De Endredy A. S.
Published: November 2013

A rapid method for removing free ferric oxides from soil clays with sodium dithionite solution buffered with sodium bicarbonate solution is described. Effective dispersion of the clay suspension during this extraction procedure is achieved by means of ultrasonic agitation. Methods are proposed for the determination of silica and alumina in the dithionite extract which are more reliable than those previously employed. Kaolinite and micaceous clay minerals are unaffected by the treatment but certain chloritic minerals appear to be susceptible to attack.
Exploration of Routes Leading to Derivatives of α‐Hydroxyalanine and its Precursors
Authors: Liwschitz Y. , Singerman A. , Wiesel Y. , Michman M. , Braun P. , Kassel S. (Hananel) , Perera D.
Published: November 2013

The preparation of fully protected derivatives of DL‐α‐hydroxyalanine is described. Several possible routes leading to protected DL‐α‐hydroxyalanine and α‐hydroxyglycine were explored. Attempts to remove the protecting groups led in most cases to the disruption of the molecule. The N‐carboxyanhydride of O‐benzyl‐DL‐α‐hydroxyalanine was prepared and trimerised to give dehydroalanyl‐O‐benzyl‐DL‐α‐hydroxyalanyldehydroalanine. This is a novel type of polymerization of N‐carboxyanhydrides concurrent with elimination of benzyl alcohol. A generally useful method of purification of oily half esters of dicarboxylic acids through their crystalline dibenzylamine salts has been developed.
The Dipole Moments of Some Halogen Substituted Isoquinolines
Authors: Weiler‐Feilchenfeld Hannah , Mao Yuh‐Lin , Bergmann E. D.
Published: November 2013

Several halogen derivatives of isoquinoline were prepared and their electric dipole moments determined. The dipole moment of isoquinoline forms an angle of approximately 110° with the bond common to both rings of the molecule.
The Mechanism of “Active Monomer” Polymerization of α‐Amino Acid N‐Carboxyanhydrides. Temperature Effects and the Significance of the Proton‐Transfer Reaction
Authors: Goodman M. , Jacobsberg L. B. , Choi N. S.
Published: November 2013

The temperature dependence of the polymerization rate is investigated using the NCA's of β‐benzyl L‐aspartate and γ ‐benzyl L‐glutamate. Activation energies for polymerizing the above NCA's are 13 and 9 Kcal per mole, respectively. Entropies of activation and Arrhenius constants, A, are also calculated and discussed in terms of the polymerization mechanism. The significance of the proton‐transfer reaction in the “active monomer” mechanism is recognized through a kinetic isotope effect and also by comparing the polymerization rates of L‐alanine NCA and its structural analog L‐alanine N‐thiocarboxyanydride. It is theorized that a changing position of equilibrium of the neutralization step decreases the concentration of “active monomer”, thereby slowing the polymerization rate.
Synthetic Peptides Related to Horse Heart Cytochrome C III. Peptides Corresponding to Positions 85–89
Authors: Wolman Y. , Klausner Y. S.
Published: November 2013

Synthesis is described of a series of peptide derivatives which corresponds to positions 85‐89 in the primary structure of horse heart Cytochrome C. The preparation of the partially protected pentapeptides: benzyloxycarbonyl‐L‐isoleucyl‐ϵ ‐trifluoroacetyl‐L‐lysyl‐ϵ ‐trifluoroacetyl‐L‐lysyl‐ϵ ‐trifluoroacetyl‐L‐lysyl‐L‐threonyl hydrazide trifluoroacetate and L‐isoleucyl‐ϵ ‐trifluoroacetyl‐L‐lysyl‐ ϵ ‐trifluoroacetyl‐L‐lysyl‐ϵ ‐trifluoroacetyl‐L‐lysyl‐L‐threonyl‐t‐butyloxycarbonyl hydrazide acetate is described.
Synthetic Peptides Related to Horse Heart Cytochrome C IV. Peptides Corresponding to Positions 90–93
Authors: Wolman Y. , Klausner Y. S.
Published: November 2013

Synthesis is described of a series of peptide derivatives which corresponds to positions 90‐93 in the primary structure of horse heart Cytochrome C. The preparation of the partially protected tetrapeptides: benzyloxycarbonyl‐L‐glutamyl‐L‐arginyl‐L‐glutamyl‐L‐aspartyl‐hydrazide trifluoroacetate and γ ‐t‐butyl‐L‐glutamyl‐L‐arginyl‐γ‐t‐butyl‐L‐glutamyl‐β‐t‐butyl‐L‐aspartyl‐t‐butyloxycarbonylhydrazide acetate is described.
Preparation of (+)‐3‐Quinuclidinol
Authors: Kalir A. , Sali E. , Shirin E.
Published: November 2013

The separation of 3‐quinuclidinol into its optical isomers and isolation of the not previously attainable (+) — enantiomer was accomplished by N‐benzylation of the amino alcohol, conversion of the quaternary base into the dibenzoyl‐D‐tartrate salt, and hydrogenolysis.
Rates and Kinetics of Hydrogen‐Bonding
Authors: De Maeyer L.C.M.
Published: November 2013

The experimental techniques for the study of the extremely fast reactions of hydrogen‐bond formation are reviewed. Direct high field dielectric and acoustic techniques as well as indirect NMR and dielectric methods are available; examples of their application to specific problems are given.

Bond formation and bond transfer reactions must be distinguished. The mechanism of bond transfer can be of different types, similar to the associative and dissociative types of substitution mechanisms that were formulated for other classes of reactions.
Adsorption Isotherms for Intermediates Formed in Charge Transfer Processes
Authors: Gileadi E.
Published: November 2013

The adsorption of phenol in the form of phenoxy radicals on the surface of a bright Pt electrode is discussed. Two main features of the adsorption isotherm are brought out. The fractional coverage Θ changes suddenly at a characteristic potential, in a manner reminiscent of two dimensional phase formation. This is attributed to the existence of an isotherm with strong lateral attraction interaction forces. The corresponding two‐dimensional equation of state resembles qualitatively the Van der Waals equation of state at temperatures below the critical temperature. For the potential dependence of adsorption a new type of isotherm is used which combines the effects of potential on charge‐transfer equilibrium and on the solvent‐solute replacement equilibrium on the surface of the electrode. The resulting function, describing the variation of Θ with E fits the observed inhibition effects of phenol on the rate of oxidation of Γ, and should also be taken into consideration in deriving Tafel slopes for different mechanisms.
Orthonormal Chemical Reactions and Chemical Relaxation Part 4. Reactions in Solution with Concomitant Entropy and Volume Changes
Authors: Hayman H.J.G.
Published: November 2013

The method described previously [2, 3] for obtaining the relaxation times, normal coordinates and normal modes of relaxation of a chemical system is extended to the case in which heat transfer and volume changes occur at rates too slow to maintain isothermal and isobaric conditions. The four types of chemical relaxation treated previously (isothermal and adiabatic relaxation at constant pressure and at constant volume) form limiting cases of this problem whose solution thus provides a generalization and unification of the concept of orthonormal chemical reactions.
Topochemistry. Part XXXII. The Crystal Structures of 9‐Methyl‐, 9‐Methoxycarbonyl‐, and 9‐Methoxyanthracene
Authors: Bart J. C. J. , Schmidt G. M. J.
Published: November 2013

The crystal structures of 9‐methyl‐, 9‐methoxycarbonyl‐, and 9‐methoxyanthracene have been solved by the SEARCH procedure and refined from partial three‐dimensional photographic data to acceptable agreement factors. The molecular shapes are briefly discussed. The packing arrangements of the first two compounds provide for antiparallel juxtaposition across inversion centres of nearest‐neighbour molecules (interplanar distances of 3.57 and 3.39 Å) and C(9) … C(10′) contacts of 3.87 and 3.68 Å. In the non‐centrosymmetric packing of 9‐methoxyanthracene the distances between meso‐carbons of nearest‐neighbour molecules are greater than 4.5 Å.
Mineralogy of Refractory Brick (50% Al2O3) Made from Negev Clays
Authors: Mishirky S. A. , Siniansky W.I.
Published: November 2013

The mineralogy of refractory bricks (50% Al2O3) made under varying conditions of temperature, pressure and grain size was investigated. Maximum temperature attained was 1450°C, pressure was varied between hand pressing and 1000 kg/cm2, grain size ranged from < 0.088 mm to 6 mm and was obtained by varying duration of the grinding process. The bricks produced were subjected to chemical and X‐ray diffraction studies, measurement of physical properties, and optical studies in thin sections. It is concluded that optimum conditions for manufacture of refractory brick are high temperature and pressure. Grain size itself is crucial, but the grinding process is far more efficient if the two starting clay materials are ground together rather than separately. It was concluded that TiO2 served as a mineralizer, and it favors well developed mullite crystal. Cristobalite was not detected at all by optical methods, while it was detected clearly by X‐ray diffraction.
Studies on the Stability of Calcium Chloraluminate
Authors: Ben‐Yair M.
Published: November 2013

Calcium chloraluminate (3CaO · Al2O3 · CaCl2 · 10H2O) is a deterioration product of Portland cement found in concrete. It is formed by the attack of chloride solutions on two of the Portland cement components: hydrated calcium aluminate and lime. A study of the synthesis and stability of calcium chloraluminate in different media are described. Calcium chloraluminate enhances the growth of high calcium sulphoaluminate crystals (3CaO · Al2O3 · 3CaSO4 · 31H2O).
Turbidity of the Suspension of Copper Montmorillonite Treated with Methylene‐Blue
Authors: Yariv S. , Lurie D.
Published: November 2013

The influence of methylene‐blue on the turbidity of suspensions of copper montmorillonite at various wavelengths was studied. Methylene‐blue is a coloured molecule and this leads to anomalies in light scattering of the montmorillonite‐methylene‐blue complex. Turbidity changes inversely with particle size.
Bromination of p‐Bromophenol in the Presence of Pyridine
Authors: Somaskandan K. , Sridhar N. , Rajaram J. , Kuriacose J.C.
Published: November 2013

The role of pyridine (Py) in the bromination of p‐bromophenol (ArH) in CCl4 has been investigated. At constant concentrations of ArH and Br2, the rate of disappearance of Br2 increases to reach a limiting value as the concentration of Py is increased. The mechanism suggested to account for the rate expression, Rate = constant [ArH] [Br2]T[Py]T, obtained from the initial rate studies, involves the interaction between ArH and the brominating species Py. Br2, in the rate determining step. Py acts as a catalyst probably by virtue of its ability to polarise the Br‐Br bond.
3,5‐Dihydroxy‐4‐Phenylisoxazole
Authors: Zvilichovsky G.
Published: November 2013

3,5‐Dihydroxy‐4‐phenylisoxazole, which is described here, is the first known 3,5‐dihydroxy derivative of isoxazole. Its unusual physical and chemical properties were studied. The tautomeric structures and the methylation products are elucidated.
Interaction Between Montmorillonite and Benzidine in Aqueous Solutions I. Adsorption of Benzidine on Montmorillonite
Authors: Lahav N. , Raziel S.
Published: November 2013

Adsorption of benzidine on montmorillonite (bentonite) particles suspended in aqueous solutions was studied by measuring the absorbance of the solution at 280 nm before and after mixing the two reactants. Benzidine adsorption decreased with an increase of suspension pH from 7 to 9.3. NaCl and calgon (Na‐hexametaphosphate) decreased the adsorption, the latter being more effective at the equivalent concentration. The interaction between benzidine and montmorillonite was connected to cation exchange processes and was influenced by the specific adsorption of the metaphosphate ion on the crystal edges.
Initiation and Propagation Steps in the Solid State Polymerization of Vinyl Monomers
Authors: Chapiro Adulphe
Published: November 2013

Several problems raised by initiation and propagation steps in solid‐state polymerizations are reviewed on the basis of data taken from the literature as well as from unpublished work. The nature of the initial active centers is briefly considered; their addition to double bonds within the crystal is discussed. Examination of initiation yields in radiation‐induced polymerizations shows that the efficiency of chain initiation rises with temperature. In most vinyl monomers, the propagation process, which is severely hindered in the crystal, presumably starts at lattice imperfections and thereafter proceeds on behalf of the additional imperfections introduced by the accumulated polymer. In a few specific cases the orientation of the double bonds in the crystal or their localization in certain regions of the crystal favours chain propagation and may result in a stereocontrolled reaction. The role of crystallite boundaries is emphasized particularly in the case of copolymerizations which take place in eutectic mixtures of two monomers.
Five Equivalent d Orbitals: A Continuum of Sets
Authors: Keaveny I. T. , Pauling Linus
Published: November 2013

A continuum of sets of five equivalent d orbitals is derived and discussed. A discussion of five equivalent sd orbitals is also presented.
The Crystal and Molecular Structure of Ethyl p‐Chloro α‐Cyano‐β‐Methyl‐Cis‐Cinnamate, C13H12No2Cl
Authors: Higuchi T. , Nagai W. , Nakatsu K. , Miwa T. , Shimada A.
Published: November 2013

Crystals of ethyl p‐chloro α‐cyano‐β‐methyl‐cis‐cinnamate, C13H12NO2Cl, are orthorhombic, space group Pbcn, with eight molecules per unit cell, a = 17.31, b = 8.68 and c = 17.20 Å. The structure was solved by direct methods and refined subsequently by Fourier techniques. The benzene ring makes a dihedral angle of 60.0° with the ethylenic group. This suggests significant steric effects of the β‐methyl group and of the carbonyl group on the orientation of the benzene ring. The conformation of the ethylene bond and the carbonyl group around the CαC bond is roughly cisoid and the angle of twist is 16.5°. Nearest‐neighbour >C = C <groups make contact across a two‐fold axis at a center‐to‐center distance of 4.33 Å.
Evolution of a Space Charge Limited Current Regime in Organic Crystals
Authors: Pope Martin , Kallmann Hartmut
Published: November 2013

Recently published data dealing with interactions of triplet excitons with trapped holes and trapped electrons in anthracene are interpreted in accordance with well‐known but often neglected concepts of the evolution of a space charge limited current (SCLC) in insulators. Discrete, closely spaced trapping levels are delineated, and it is proposed that SCLC do not commence in some crystals until the applied voltage exceeds 2000 V. It is suggested that dimer clusters act as trapping sites.
Bridging in β‐Haloalkyl Radicals a Critique of Published Criticisms
Authors: Skell Philip S. , Shea Kenneth J.
Published: November 2013

The evidence in support of bridging in β‐halogen alkyl radicals together with an examination of the criticisms of this hypothesis are reviewed and analyzed.
Distortion of Excited Molecules in Organic Solids
Authors: Hochstrasser Robin M. , Wiersma Douwe A.
Published: November 2013

In this paper we present some ideas concerning the role of the crystal field in stabilizing dynamically distorted electronic states of aromatics. It is shown that a crystal field term of appropriate symmetry reveals in a dramatic way the result of strong vibronic coupling in emission spectra. Conditions under which these distortions are bound to occur are discussed with an emphasis on qualitative understanding. In this context the role of predissociating modes in spectra of aromatics is touched upon and the ideas are demonstrated through discussions of the emission spectra of pyrazine, p‐dibromobenzene and m‐dichloropyrazine.
The Crystal and Molecular Structures of the Centrosymmetric Hexa‐o‐Phenylene
Authors: Irngartinger Hermann
Published: November 2013

The crystal structure of the centrosymmetric isomer of hexa‐o‐phenylene has been solved by direct methods from counter data collected with MoKα radiation on a computer‐controlled diffractometer by the balanced‐filter technique and has been refined to R = 0.046. The deviation of the observed structure from an idealized regular geometry is assigned to intra‐ and intermolecular repulsions. The length of the bond linking the benzene rings is 1.498 Å, the angle of twist between the planes of the benzene rings is 77.4°. The packing arrangement shows a pseudo‐trigonal pattern.
Potentiometric Microdetermination of Boron in Industrial Brines and in Concentrated Salt Solutions
Authors: Scher Aharon , Cogan Edward
Published: November 2013

As little as 0.1 mg boron (1 mg/liter) may be determined in salt solutions containing as much as 400 g/liter MgCl2, MgBr2, NaCl, KCl and CaCl2 or in analytical reagent grade salts with an accuracy of 2% relative. The lower monovalent alcohols do not interfere. The two equivalent points, the gap between them and the role of ionic strength are discussed.
Fluorescence Quenching in Benzene Vapor
Authors: Luria Menachem
Published: November 2013

The fluorescence quenching in benzene vapor is investigated, using lifetime measurements. The self‐quenching reaction is studied at various temperatures and the activation energy for this process is determined to be 950 cm−1. The effect of some simple gases on the fluorescence lifetime is also studied.
Interactive Gel Networks for Organic Chemical Separations
Authors: Freeman David H.
Published: November 2013

A comparison is drawn between the fundamental logic of the origin of ion exchange affinity, and that of the newly discovered behavior of interactive gels. The basis for predicting interactive chromatographic affinity is examined.
Kinetics of HCl Uptake by Macroporous Weak‐Base Anion Exchangers
Authors: Oke R. B. , Millar J. R.
Published: November 2013

The kinetics of uptake at 25° of 0.01 N HCl by dimethylamine‐aminated macroporous resins depend in a complex manner on the porosity of the resin. While pure C‐ and P‐kinetics are observed respectively at the nonporous and highly macroporous ends of the porosity scale, under the experimental conditions employed the diffusional and chemical fluxes are similar in magnitude, and either pseudo‐P or pseudo‐C kinetics may be shown at intermediate porosity levels, of which three examples have been examined.
Some Biochemical Processes Induced by Radiation as Studied by Pulse Radiolysis
Authors: Swallow A. J.
Published: November 2013

The main types of biochemically important electron transfer substances can be made to undergo reactions under irradiation which in some ways mimic those which occur in nature. In the case of NAD+, pulse radiolysis shows that electrons add to the pyridine ring forming an NAD· radical with a characteristic absorption in the visible range which is capable of transferring its electron to oxygen. Using simpler pyridinyl compounds it has been found that, as well as the absorptions in the visible range, the radicals exhibit absorptions in the infrared range which correlate well with transitions which may be deduced from the known charge‐transfer bands of the parent compound. The NAD· radical can be made by one‐electron oxidation of NADH as well as by reduction of NAD+, and the reaction with oxygen enables NADH to be converted into NAD+ by an unambiguous free radical route. Cytochrome‐c can be reduced either by hydrated electrons or CO2−. In solution buffered to neutral pH, the reduction gives rise immediately to normal reduced cytochrome‐c, but in mildly alkaline solution, an unstable reduced form appears whose conformation changes over a fraction of a second to that of normal reduced cytochrome‐c. As well as the hydrated electron and CO2−, the superoxide anion radical O2− has also been found to reduce cytochrome‐c. This reaction is very slow (k ∼ 105 M−1 sec−1).
Radiolysis of Ribonuclease in Controlled Environments
Authors: Adelstein S. J. , Mee L. K. , Stein G.
Published: November 2013

The separate contributions of the primary aqueous radicals to the changes in activity, molecular configuration and amino acid composition of RNase, produced by γ‐irradiation of dilute solutions, have been identified. The most effective radical for inactivation is the H atom. Additional molecular products are formed on irradiation of the enzyme. Amino acid analyses of the irradiation products show significant damage only to the aromatic and sulfur‐containing residues.
Pulse Radiolysis and Inactivation of Trypsin
Authors: Ovadia Jaques
Published: November 2013

A study of the mechanism of aqueous trypsin inactivation by radiation was carried out by pulse radiolysis and steady irradiation in the presence of various scavengers. The initial products consist of OH radical and H atom adducts to tryptophan residues, and of electron adduct to cystine residues. Essentially, all OH react with trypophan with k(OH + trypsin) = (8.2 ± 1.2) × 1010 M−1 sec−1. The electron adduct to the disulphide bond accounts for about 60 per cent of the electron yield, with k(eaq + trypsin) = (3.5 ± 0.8) × 1010 M−1 sec−1. Measurements of tryptophan residue loss and sulphydryl formation under different irradiation conditions show that the initial reactions are substantially reversible, except for the destruction of tryptophan under aerobic conditions. Many primary radicals induce inactivation with low independent probabilities, indicating that only a small fraction of the possible reaction sites for each species influence the integrity of the active center.
Factors which Influence the Sedimentation Properties of Mammalian Cell DNA: Effect of Two‐Dose X‐Irradiation
Authors: Belli James A. , Nagle William
Published: November 2013

The sedimentation behavior of DNA extracted from mammalian cells was studied after fractionated irradiation. Our results show that the injury registered by a second X‐ray dose is not additive to that registered by the first, and that DNA, having repaired its initial radiation damage, is less susceptible to a subsequent irradiation. The following hypothesis is suggested. Repair processes of DNA begin with unmasking of “initiation sites” and that, in time, these become associated with membrane material within the nucleus.
Kinetics of Film Diffusion Controlled Ion Exchange Processes, Theory and Applications
Authors: Bunzl K.
Published: November 2013

A differential equation describing the kinetics of film diffusion controlled ion exchange processes is derived on the basis of the theory of irreversible thermodynamics. This equation is solved subsequently with the boundary conditions of infinite solution volume and applied to some experimental results involving differential ion exchange reactions. In case of the boundary conditions of a finite solution volume, the kinetics of dissolution of a sparingly soluble salt by an ion exchanger is considered.
Ammonium Chloride Separated into Ammonia and Hydrogen Chloride, with the Aid of Metal Oxides
Authors: Ashboren (Araten) David
Published: November 2013

The two‐stage decomposition of ammonium chloride into ammonia and hydrogen chloride, with the aid of metal oxides, was investigated. Twenty‐one oxides were considered for this sequence, and 14 were actually tested and the temperature range of the reactions determined. The energy requirements for heating the metal chlorides from t1 to t2 were calculated. For Fe2 O3, the temperatures are 200° and 300°, respectively, and the heating requirement ca. 17 × 103 kcal/t NH4Cl converted.
Anionic Graft Polymerization of Lauryl Methacrylate on Starch
Authors: Cohen Eliahu , Zilkha Albert
Published: November 2013

The anionic graft polymerization of lauryl methacrylate on the potassium alkoxide derivative of starch was studied. The yield of graft polymer increased with increasing alkoxide concentration. With increasing monomer concentration and with increasing temperature, the extent of homopolymer formation increased. The composition of the graft polymers depends on the reaction conditions; graft polymers having about 30–65% polylauryl methacrylate were obtained.
Adsorption of Heavy Metal Salts by Cotton Fabrics Containing Polyethylene and Polypropylene Sulfide
Authors: Avny Yair , Leonov David , Zilkha Albert
Published: November 2013

The adsorption of mercury and other heavy metal salts by cotton fabrics containing polyethylene and polypropylene sulfide was investigated. Adsorption of mercuric chloride from aqueous solution was investigated in detail, and AH of the reaction was determined. A general screening of the capacity of adsorption of the polymers for heavy metal salts was carried out. Differences in behavior between the polymeric system and simple thioethers were observed. Auric, antimony, titanium, palladium, platinum and bismuth salts were adsorbed by the modified cotton; other salts, known also to complex with organic sulfides, were not adsorbed.