bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of Surplus in Life Insurance
Authors: Ramlau-Hansen Henrik 
Published: March 2006

AbstractThis paper discusses distribution of surplus in life insurance within a general Markov chain framework. A conservative interest rate and a conservative set of transition intensities are used for reserving purposes whereas more realistic assumptions are used for the purpose of distributing surplus. The paper examines various actuarial aspects of distributing surplus through either cash bonuses, terminal bonuses or increased benefits. The results are illustrated by some examples.
Separating True IBNR and IBNER Claims
Authors: Schnieper R. 
Published: March 2006

AbstractA simple model for IBNR claims is presented. Estimates for the loss reserves and for the ultimate claims rate are derived. Approximations to the mean square error of the estimators are produced. A more specific parametric model is suggested for the case that we deal with claim numbers instead of claim amounts. The general method is illustrated by a practical application to the pricing of a casualty excess of loss cover.
The Schmitter Problem and a Related Problem: A Partial Solution
Authors: Kaas R. 
Published: March 2006

AbstractAt the 1990 ASTIN-colloquium, Schmitter posed the problem of finding the extreme values of the ultimate ruin probability ψ(u) in a risk process with initial capital u, fixed safety margin θ, and mean μ and variance σ2 of the individual claims. This note aims to give some more insight into this problem. Schmitter's conjecture that the maximizing individual claims distribution is always diatomic is disproved by a counterexample. It is shown that if one uses the distribution maximizing the upper bound e−Ru to find a ‘large’ ruin probability among risks with range [0, b], incorrect results are found if b is large or u small.The related problem of finding extreme values of stop-loss premiums for a compound Poisson (λ) distribution with identical restrictions on the individual claims is analyzed by the same methods. The results obtained are very similar.
Risk Theory with the Gamma Process
Authors: Dufresne François , Gerber Hans U. , Shiu Elias S. W. 
Published: March 2006

AbstractThe aggregate claims process is modelled by a process with independent, stationary and nonnegative increments. Such a process is either compound Poisson or else a process with an infinite number of claims in each time interval, for example a gamma process. It is shown how classical risk theory, and in particular ruin theory, can be adapted to this model. A detailed analysis is given for the gamma process, for which tabulated values of the probability of ruin are provided.
Evaluating Compound Generalized Poisson Distributions Recursively
Authors: Goovaerts M. J. , Kaas R. 
Published: March 2006

AbstractIn this paper we give a recursive scheme, involving Panjer's recursion, to compute the distribution of a compound sum of integer claims, when the number of summands follows a Generalized Poisson distribution. Also, an elegant derivation is given for some basic properties of this counting distribution.
Discriminative features of type I and type III secreted proteins from Gram-negative bacteria
Authors: Zikmanis Peteris , Andersone Inara , Baltkalne Martina 
Published: March 2006

AbstractThe amino acid composition of sequences and structural attributes (α-helices, β-sheets) of C-and N-terminal fragments (50 amino acids) were compared to annotated (SWISS-PROT/ TrEMBL) type I (20 sequences) and type III (22 sequences) secreted proteins of Gram-negative bacteria.The discriminant analysis together with the stepwise forward and backward selection of variables revealed the frequencies of the residues Arg, Glu, Gly, Ile, Met, Pro, Ser, Tyr, Val as a set of strong (1-P < 0.001) predictor variables to discriminate between the sequences of type I and type III secreted proteins with a cross-validated accuracy of 98.6–100 %. The internal and external validity of discriminant analysis was confirmed by multiple (15 repeats) test-retest procedures using a randomly split original set of proteins; this validation method demonstrated an accuracy of 100 % for 191 non-selected (retest) sequences.The discriminant analysis was also applied using selected variables from the propensities for β-sheets and polarity of C-terminal fragments. This approach produced the next highest and comparable cross-validated classification accuracy for randomly selected and retest proteins (85.4–86.0 % and 82.4–84.5 %, respectively).The proposed sets of predictor variables could be used to assess the compatibility between secretion substrates and secretion pathways of Gram-negative bacteria by means of discriminant analysis.
Chondroitin sulfate-modified LDL induces increased cholesteryl ester synthesis and down-regulation of LDL receptors in smooth muscle cells and macrophages
Authors: Tircol Magdalena , Tirziu Daniela , Simionescu Maya 
Published: March 2006

Abstract
Hypercholesterolemia induces increased transcytosis and accumulation of plasma lipoproteins in the arterial intima, where they interact with matrix proteins and become modified and reassembled lipoproteins. Chondroitin 6-sulfate-modified LDL (CS-mLDL) induces migration, proliferation, and lipid accumulation in human aortic smooth muscle cells (SMCs). To search for the mechanism(s) responsible for lipid accumulation, cultured SMC and macrophages were exposed to CS-mLDL, minimally modified LDL (mmLDL), and native LDL (as a control). Then the cellular uptake, degradation and expression of the LDL receptor (LDL-R) was determined using radioiodinated ligands, ACAT activity assay, fluorescence microscopy and RT-PCR. The uptake of CS-mLDL was 2-fold higher in SMC and 3-to 4-fold higher in macrophages as compared to LDL and mmLDL; the lysosomal degradation of CS-mLDL was slower in SMCs and considerably diminished in macrophages. Compared with LDL, CS-mLDL induced increased synthesis and accumulation of esterified cholesterol in SMCs (∼2-fold) and macrophages (∼10-fold) within an expanded acidic compartment. CS-mLDL and mmLDL down-regulate the gene expression of the LDL-R in the both cell types. Mechanisms of CS-mLDL-induced lipid accumulation in SMC and macrophages involve increased cellular uptake, and diminished cellular degradation that stimulates cholesterol ester synthesis and accumulation in cytoplasmic inclusions and in the lysosomal compartment in an undegraded form; modified lipoproteins induce down-regulation of LDL-R.
The ARX mutations: A frequent cause of X‐linked mental retardation
Authors: Nawara Magdalena , Szczaluba Krzysztof , Poirier Karine , Chrzanowska Krystyna , Pilch Jacek , Bal Jerzy , Chelly Jamel , Mazurczak Tadeusz 
Published: March 2006

AbstractThe ARX gene mutations have been demonstrated to cause different forms of mental retardation (MR). Beside FMR1, in families with X‐linked mental retardation (XLMR), the ARX dysfunction was demonstrated to be among the most frequent causes of this heterogeneous group of disorders. Nevertheless, in sporadic cases of MR, ARX mutations are extremely rare. In order to evaluate the frequency of ARX mutation in XLMR, we performed mutational analysis of ARX in 165 mentally retarded probands negative for FRAXA and belonging to families in which the condition segregates as an X‐linked condition. The same recurrent mutation, an in frame 24 bp insertion (c.428‐451dup (24 bp)), was identified in five patients. In one family, the mother of two affected boys was found not to carry the mutation detected in her sons. These data suggest the presence of germline mosaicism for the mutation in the mother. Our results confirm the significant contribution of ARX mutations in the etiology of MR, especially in this group of patients selected for XLMR (3%). These data, together with those reported in the literature, imply that screening for c.428‐451 dup (24 bp) mutation should be recommended in all patients with suspected XLMR. © 2006 Wiley‐Liss, Inc.
The effect of dopamine D2, D5 receptor and transporter (SLC6A3) polymorphisms on the cue‐elicited heroin craving in Chinese
Authors: Li YiFeng , Shao ChunHong , Zhang Dandan , Zhao Min , Lin Ling , Yan Pengrong , Xie Yuying , Jiang Kaida , Jin Li 
Published: March 2006

AbstractHeroin dependence is resulted from the interaction between multiple genetic and environmental factors. Subjective craving is considered to be a central phenomenon, which contributes to the continuation of drug use in active abuser and the occurrence of relapse in detoxified abusers. Dopamine pathway has been implicated in the cue‐elicited craving for a variety of addictive substances. The objective of this study was to test the hypothesis that heroin addicts carrying specific variants in dopamine‐related genes would have higher levels of craving following exposure to a heroin‐related cue. Craving induced by a series of exposure to heroin‐related cue was assessed in a cohort of Chinese heroin abuser (n = 420) recruited from natural abstinence center at Shanghai. Significantly stronger cue‐elicited heroin craving was found in individuals carrying D2 dopamine receptor gene (DRD2) TaqI RFLP A1 allele than the non‐carriers (P < 0.001). Furthermore, we did not observed significant association of cue‐elicited craving with the nine‐repeat allelic variants in dopamine transporter gene (DAT) SLC6A3 and with the dinucleotide repeat polymorphism (DRP) 148bp allele in D5 dopamine receptor gene (DRD5). The results of our study suggest that human dopamine pathway be involved in cue‐induced heroin craving, and indicate a potential genetic risk factor for persistent heroin behavior and relapse. © 2006 Wiley‐Liss, Inc.
Evaluation of RGS4 as a candidate gene for schizophrenia
Authors: Liu Yu‐Li , Shen‐Jang Fann Cathy , Liu Chih‐Min , Wu Jer‐Yuarn , Hung Shuen‐Iu , Chan Hung‐Yu , Chen Jiahn‐Jyh , Lin Chin‐Yu , Liu Shih‐Kai , Hsieh Ming H. , Hwang Tzung‐Jeng , OuYang Wen‐Chen , Chen Chun‐Ying , Lin Jin‐Jia , Chou Frank Huang‐Chih , Chueh Ching‐Mo , Liu Wei‐Ming , Tsuang Ming‐Min , Faraone Stephen V. , Tsuang Ming T. , Chen Wei J. , Hwu Hai‐Gwo 
Published: March 2006

AbstractSeveral studies have suggested that the regulator of G‐protein signaling 4 (RGS4) may be a positional and functional candidate gene for schizophrenia. Three single nucleotide polymorphisms (SNP) located at the promoter region (SNP4 and SNP7) and the intron 1 (SNP18) of RGS4 have been verified in different ethnic groups. Positive results have been reported in these SNPs with different numbers of SNP combinatory haplotypes. In this study, these three SNP markers were genotyped in 218 schizophrenia pedigrees of Taiwan (864 individuals) for association analysis. Among these three SNPs, neither SNP4, SNP7, SNP18 has shown significant association with schizophrenia in single locus association analysis, nor any compositions of the three SNP haplotypes has shown significantly associations with the DSM‐IV diagnosed schizophrenia. Our results fail to support the RGS4 as a candidate gene for schizophrenia when evaluated from these three SNP markers. © 2006 Wiley‐Liss, Inc.
Glutamate AMPA receptor subunit 1 gene (GRIA1) and DSM‐IV‐TR schizophrenia: A pilot case‐control association study in an Italian sample
Authors: Magri Chiara , Gardella Rita , Barlati Stefano Davide , Podavini Damiano , Iatropoulos Paraskevas , Bonomi Silvia , Valsecchi Paolo , Sacchetti Emilio , Barlati Sergio 
Published: March 2006

AbstractGlutamatergic dysfunction is one of the major hypotheses for the pathogenesis of schizophrenia. The GRIA1 gene encodes for one (GluR1) of the four (GluR1–4) ionotropic AMPA receptor subunits. GRIA1 is a good candidate gene for susceptibility to schizophrenia since it maps in 5q33, a region where the presence of susceptibility loci has been suggested by independent genome‐wide scans and because its expression has been found to be decreased in the brain of some schizophrenia patients. We present data from a case‐control association study on the Italian population with eight polymorphisms spanning the whole GRIA1 gene. Single‐locus analysis revealed a significantly different allele distribution in cases and in controls of two SNPs (rs707176, 0.41 vs. 0.31, P = 0.009; rs2963944, 0.41 vs. 0.30, P = 0.007), and one microsatellite (rs10631988, allele 9: 0.40 vs. 0.29, P = 0.004). Haplotype analysis showed an increased frequency of a specific haplotype for these markers (C09CC, 0.39 vs. 0.28, P = 0.009). Therefore our data indicate that GRIA1 may be involved in susceptibility to DSM‐IV‐TR schizophrenia. © 2006 Wiley‐Liss, Inc.
Lack of association between UBQLN1 and Alzheimer disease
Authors: Slifer M.A. , Martin E.R. , Bronson P.G. , Browning‐Large C. , Doraiswamy P.M. , Welsh‐Bohmer K.A. , Gilbert J.R. , Haines J.L. , Pericak‐Vance M.A. 
Published: March 2006

AbstractAlzheimer disease (AD) is heterogeneous and complex with a strong genetic diathesis. It is the most common cause of dementia affecting the elderly. Linkage studies [Kehoe et al., 1999; Hum Mol Genet 8: 237–245]; [Pericak‐Vance et al., 2000; Exp Gerontol 35: 1343–1352]; [Myers et al., 2002; Am J Med Genet 114: 235–244]; [Blacker et al., 2003; Hum Mol Genet 12: 23–32] identified chromosome 9q as a region containing a possible AD candidate gene. Functional protein studies [Mah et al., 2000; J Cell Biol 151: 847–862]; [Ko et al., 2002; J Biol Chem 277: 35386–35392] identified the UBQLN1 gene on chromosome 9q that encodes ubiquilin as a likely candidate for a role in late‐onset AD pathogenesis. A recent family‐based study by [Bertram et al., 2005; N Engl J 352: 884–894] reported genetic association and expression evidence for a putative AD risk allele of an intronic single nucleotide polymorphism (SNP) within the UBQLN1 gene. In this study, we comprehensively assessed whether any of seven polymorphisms located across the UBQLN1 gene are associated with AD in another large family‐based data set and an independent case‐control data set. We found no significant association of AD risk with any of the seven SNPs genotyped (including those SNPs previously reported by Bertram et al.) in either the family‐based or case‐control data set. Age‐specific analyses and analyses conditional on Apolipoprotein E (ApoE) genotype and sex also revealed no significant associations to AD risk in either data set. Using age at onset (AAO) as a quantitative trait revealed a modest age modifying association; however, the results were inconsistent between the data sets. Our results suggest that UBQLN1 variants do not increase risk for AD in these data. © 2006 Wiley‐Liss, Inc.
Synthesis and evaluation of a composite crosslinked copolymer as a particulate fluid diversion agent
Authors: Lu Hongsheng , Huang Zhiyu , Li Peiwu , Ma Yong , Feng Yujun 
Published: March 2006

AbstractTo meet the needs for polymer particulates for the flooding of oil fields, a composite crosslinked copolymer of hydrophilic monomers [acrylamide (AM) and acrylic acid (AA)] and a hydrophobic monomer [methyl methacrylate (MMA)] was synthesized. In this study, we first added a rare‐earth thermal stabilizer and inorganic montmorillonite (MMT) clay to the copolymer; this showed that the composite crosslinked copolymer exhibited good water‐swelling performance at 200°C, with gel static grade of 5, a toughness index of 1.1170, and a salinity limit of 250,000 mg/L. It also had better injection abilities. The AM/AA/MMA ratio was 4 : 1 : 0.03 w/w, the crosslinker additive content was 0.03 wt %, the thermal stabilizer additive content was 5 wt %, and the clay (MMT) additive content was 13 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4429–4433, 2006
Photooxidation of benzil groups in the presence of hindered amine stabilizers in the polystyrene film
Authors: Kósa C. , Mosnáček J. , Lukáč I. , Hrdlovič P. , Chmela š. , Habicher W. D. 
Published: March 2006

AbstractThe photoperoxidation at λ > 400 nm of benzil (BZ) groups with the air oxygen to benzoyl peroxide (BP) groups in the polystyrene matrices was investigated in the presence of hindered amine stabilizer (HAS). HAS was used as a free molecule or was bound in combined molecule with BZ. HAS was in the form of parent amine as 2,2,6,6‐tetramethyl‐4‐hydroxypiperidine (TMP) and in the form of stable nitroxyl radical 1‐oxo‐2,2,6,6‐tetramethyl‐4‐hydroxypiperidine (NO). Both HAS forms effected the photooxidation of BZ structures. The main product of the photooxidation in the presence of parent amine TMP as well as in its absence is benzoyl peroxide (BP). The rate of BZ consumption increases in the presence of TMP. Irradiation of BZ in the presence of sufficient concentration of freely added NO results only in the formation of benzoic acid esters and benzoic acid, which are the main decomposition products of BP. The benzoic acid esters/benzoic acid ratio increases with the increasing concentration of NO. Bounding of BZ and TMP into one molecule (BZNH) results in slower dicarbonyl depletion, as compared with the case when mixture of BZ and TMP was used. Very slow depletion of BZ carbonyl absorption was observed in the case of bounded BZ and NO in one molecule (BZNO), in comparison with the mixture of free NO and BZ. In the case of BZNO, an effective intramolecular quenching of BZ excited triplet states with NO structures proceeds. Steady stay and dynamic emission (phosphorescence) measurements also show an effective quenching of BZ excited states by unbounded or bounded NO. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4420–4428, 2006
Effect of starch addition on compression‐molded poly(3‐hydroxybutyrate)/starch blends
Authors: Thiré Rossana M. S. M. , Ribeiro Thiago A. A. , Andrade Cristina T. 
Published: March 2006

AbstractBecause of their biocompatibility and total biodegradability, poly(3‐hydroxybutyrate) (PHB) and starch have attracted attention as promising raw materials for manufacture of single‐use plastic items and biomaterials. PHB/maize starch blends with starch contents in the range of 0–50 wt % were processed in an internal mixer, and their compression‐molded films were characterized by tensile tests, X‐ray diffraction, thermogravimetric analysis, wettability measurements, and scanning electron microscopy. Water and glycerol were used as plasticizers. The results indicated that the thermal degradation behavior of the blends were similar to that of pure PHB films. All the blends showed heterogeneous morphology, wherein starch granules were dispersed in continuous PHB‐rich matrix. Despite the decrease in elongation at break and tensile strength, starch incorporation of up to 30 wt % into PHB matrix resulted in materials as hard as pure PHB films, but exhibiting less crystallinity and more hydrophilic character, which might lead to a higher biodegradation rate. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4338–4347, 2006
Properties of hydrophobically modified polyacrylamide with low molecular weight and interaction with surfactant in aqueous solution
Authors: Wu Shuhui , Shanks Robert A. , Bryant Gary 
Published: March 2006

AbstractHydrophobically modified polyacrylamide (HMPAM), with a molecular weight of 104 g/mol, was studied using a range of rheological methods and dynamic light scattering (DLS). DLS measurements indicate that the association of the modified polymer begins at low concentration. The modified polymer with high substitution forms transient networks below the critical concentration, but the networks are disrupted by the micelles formed by the polymer itself, and the networks do not contribute to viscosity enhancement. The modified polymers exhibited surface activity, and so they may be regarded as nonionic polymeric surfactants rather than thickeners. On the other hand, HMPAM is shown to interact with the surfactant SDS while PAM is inert to SDS. In the hydrophobic domains, it undergoes a surfactant‐induced association process; in the hydrophobe‐surfactant transition regions, the surfactant binds to the polymer in a noncooperative way and forms a polymer–surfactant complex. Contracted polymer chains begin to extend because of electrostatic repulsion, which can overcome the association at surfactant domains. The conformation of HMPAM polymer chains could be controlled by adding a specific amount of surfactant. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4348–4360, 2006
Synthesis and properties of nanosilica‐reinforced polyurethane for grouting
Authors: Xiang X. J. , Qian J. W. , Yang W. Y. , Fang M. H. , Qian X. Q. 
Published: March 2006

AbstractA polyurethane/nanosilica (PU/SiO2) hybrid for grouting was prepared in a two‐step polymerization using poly(propylene glycol) diols as the soft segment, toluene 2,4‐diisocyanate (TDI) as the diisocyanate, 3,3′‐dichloro‐4,4′‐diaminodiphenylmethane (MOCA) as the chain extender, and acetone as the solvent. The size and dispersion of nanosilica, the molecular structure, mechanical properties, rheological behavior, thermal performance, and the UV absorbance characteristic of the PU/SiO2 hybrid were investigated by transmission electron microscopy (TEM), FTIR, mechanical tests, viscometry, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and UV spectroscopy. Nanosilica dispersed homogeneously in the PU matrix. The maximum values of mechanical properties such as tensile strength, elongation break, and adhesive strength showed an addition of nanosilica of about 2 wt %. Resistance to both high and low temperatures was better than with PU. And the UV absorbance of the PU/SiO2 hybrid increased in the range of 290–330 nm with increasing nanosilica content. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4333–4337, 2006
Preparation of alginate/poly(N‐isopropylacrylamide) semi‐interpenetrating and fully interpenetrating polymer network hydrogels with γ‐ray irradiation and their swelling behaviors
Authors: Lee Sang Bong , Park Eun Kyoung , Lim Youn Mook , Cho Seong Kwan , Kim So Yeon , Lee Young Moo , Nho Young Chang 
Published: March 2006

AbstractSemi‐interpenetrating polymer network (semi‐IPN) and fully interpenetrating polymer network (full‐IPN) hydrogels composed of alginate and poly(N‐isopropylacrylamide) were prepared with γ‐ray irradiation. The semi‐IPN hydrogels were prepared through the irradiation of a mixed solution composed of alginate and N‐isopropylacrylamide (NIPAAm) monomer to simultaneously achieve the polymerization and self‐crosslinking of NIPAAm. The full‐IPN hydrogels were formed through the immersion of the semi‐IPN film in a calcium‐ion solution. The results for the swelling and deswelling behaviors showed that the swelling ratio of semi‐IPN hydrogels was higher than that of full‐IPN hydrogels. A semi‐IPN hydrogel containing more alginate exhibited relatively rapid swelling and deswelling rates, whereas a full‐IPN hydrogel showed an adverse tendency. All the hydrogels with NIPAAm exhibited a change in the swelling ratio around 30–40°C, and full‐IPN hydrogels showed more sensitive and reversible behavior than semi‐IPN hydrogels under a stepwise stimulus. In addition, the swelling ratio of the hydrogels continuously increased with the pH values, and the swelling processes were proven to be repeatable with pH changes. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4439–4446, 2006