bluuebunny/crossref_metadata_2025 huggingface dataset:
The role of crystal fabric in flow near an ice divide
Authors: Pettit Erin C. , Thorsteinsson Throstur , Jacobson H. Paul , Waddington Edwin D.
Published: December 2007

Polycrystalline ice near an ice divide typically shows a crystal fabric (crystal preferred orientation) with c axes clustered vertically. We explore the effect of this fabric on the large-scale flow pattern near an ice divide. We incorporate an analytical formulation for anisotropy into a non-linear flow law within a finite-element ice-sheet flow model. With four different depth profiles of crystal fabric, we find that the effect of fabric is significant only when a profile has a minimum cone angle of less than ~25º. For a steady-state divide, the shape and size of the isochrone arch can depend as much on the crystal fabric as it does on the non-linearity of ice flow. A vertically oriented fabric tends to increase the size of the isochrone arch, never to reduce it. Also, non-random fabric has little effect on the ice-divide-flow pattern when ice is modeled as a linear (Newtonian) fluid. Finally, when we use a crystal-fabric profile that closely approximates the measured profile for Siple Dome, West Antarctica, the model predicts concentrated bed-parallel shearing 300 m above the bed.
A laboratory study of ploughing
Authors: Rousselot Marie , Fischer Urs H.
Published: December 2007

A new laboratory device is used to investigate the resistance to clast ploughing at the base of glaciers. In experiments in which a ploughing tip is dragged at different velocities and effective normal stresses through water-saturated sediment from Unteraargletscher, Switzerland, pore pressures above and below the hydrostatic level develop around the tip. The absolute magnitude of these nonhydrostatic pore pressures increases with the ploughing velocity but remains small compared to the sediment yield strength, so that the pore pressures do not significantly weaken the sediment. The shear stress on the tip is independent of the velocity but scales with the applied effective normal stress, in agreement with a Coulomb-plastic behavior of the sediment. The results indicate that, depending upon position close to the object, both sediment compaction and dilation can influence the pore-pressure distribution and thus the sediment yield strength. Comparison with other studies of clast ploughing suggests that the significance of sediment weakening in front of ploughing clasts may depend on the relative magnitudes of the non-hydrostatic pore pressures. Therefore, depending on the dominant pore-pressure response of the deforming sediment, clast ploughing may have the potential to either trigger ice-flow instabilities or stabilize glacier motion.
Glacier-dammed lake outburst events of Gornersee, Switzerland
Authors: Huss Matthias , Bauder Andreas , Werder Mauro , Funk Martin , Hock Regine
Published: December 2007

Gornersee, Switzerland, is an ice-marginal lake, which drains almost every year, subglacially, within a few days. We present an analysis of the lake outburst events between 1950 and 2005, as well as results of detailed field investigations related to the lake drainage in 2004 and 2005. The latter include measurements of lake geometry, water pressure in nearby boreholes and glacier surface motion. A distributed temperature-index melt model coupled to a linear-reservoir runoff model is used to calculate hourly discharge from the catchment of Gornergletscher in order to distinguish between the melt/precipitation component and the outburst component of the discharge hydrograph. In this way, drainage volume and timing are determined. From 1950 there is a clear trend for the outburst flood to occur earlier in the melt season, but there is no trend in lake discharge volumes. Peak discharges from the lake lie significantly below the values obtained using the empirical relation proposed by Clague and Mathews (1973). The shapes of the 2004 and 2005 lake outflow hydrographs differ substantially, suggesting different drainage mechanisms. From water balance considerations we infer a leakage of the glacier-dammed lake in 2005, starting 1 week prior to the lake outburst. During the drainage events, up to half of the lake water is temporarily stored in the glacial system, causing substantial uplift of the glacier surface.
Increased water storage at ice-stream onsets: a critical mechanism?
Authors: Bindschadler Robert , Choi Hyeungu
Published: December 2007

The interdependence of rapid ice flow, surface topography and the spatial distribution of subglacial water are examined by linking existing theories. The motivation is to investigate whether the acceleration of an ice-stream tributary contains a positive feedback that encourages the retention of subglacial water that leads to faster flow. Periodically varying surface and bed topographies are related through a linear ice-flow perturbation theory for various values of mean surface slope, perturbation amplitude and basal sliding speeds. The topographic variations lead to a periodic variation in hydraulic potential that is used to infer the tendency for subglacial water to be retained in local hydraulic potential minima. If water retention leads to enhanced basal sliding, a positive feedback loop is closed that could explain the transition from slower tributary flow to faster-streaming flow and the sustained downstream acceleration along the tributary–ice-stream system. A sensitivity study illustrates that the same range of topographic wavelengths most effectively transmitted from the bed to the surface also strongly influences the behavior of subglacial water. A lubrication index is defined to qualitatively measure the heterogeneity of the subglacial hydrologic system. Application of this index to field data shows that the transition from tributary to ice stream closely agrees with the location where subglacial water may be first stored.
Simulating complex snow distributions in windy environments using SnowTran-3D
Authors: Liston Glen E. , Haehnel Robert B. , Sturm Matthew , Hiemstra Christopher A. , Berezovskaya Svetlana , Tabler Ronald D.
Published: December 2007

We present a generalized version of SnowTran-3D (version 2.0), that simulates wind-related snow distributions over the range of topographic and climatic environments found globally. This version includes three primary enhancements to the original Liston and Sturm (1998) model: (1) an improved wind sub-model, (2) a two-layer sub-model describing the spatial and temporal evolution of friction velocity that must be exceeded to transport snow (the threshold friction velocity) and (3) implementation of a three-dimensional, equilibrium-drift profile sub-model that forces SnowTran-3D snow accumulations to duplicate observed drift profiles. These three sub-models allow SnowTran-3D to simulate snow-transport processes in variable topography and different snow climates. In addition, SnowTran-3D has been coupled to a high-resolution, spatially distributed meteorological model (MicroMet) to provide more realistic atmospheric forcing data. MicroMet distributes data (precipitation, wind speed and direction, air temperature and relative humidity) obtained from meteorological stations and/or atmospheric models located within or near the simulation domain. SnowTran-3D has also been coupled to a spatially distributed energy- and mass-balance snow-evolution modeling system (SnowModel) designed for application in any landscape and climate where snow is found. SnowTran-3D is typically run using temporal increments ranging from 1 hour to 1 day, horizontal grid increments ranging from 1 to 100 m and time-spans ranging from individual storms to entire snow seasons.
Remote sounding of Greenland supraglacial melt lakes: implications for subglacial hydraulics
Authors: Box Jason E. , Ski Kathleen
Published: December 2007

A supraglacial lake-depth retrieval function is developed, based on the correspondence between moderate-resolution imaging spectroradiometer (MODIS) reflectance and water depth measured during raft surveys. Individual lake depth, area and volume statistics, including short-term temporal changes for Greenland’s southwestern ablation region, were compiled for 2000–05. The maximum area of an individual lake was found to be 8.9 km2, the maximum volume 53.0 × 106 m3 and the maximum depth 12.2 m, sampling over 0.0625 km2 pixel areas. The total lake volume reaches >1 km3 in this region by July each year. The importance of melt lake reservoirs to Greenland ice-sheet flow may be a feedback between abrupt lake drainage events and ice dynamics. Lake-outburst volumes up to 31.5 × 106 m3 d−1 are capable of providing sufficient water via moulins to hydraulically pressurize the subglacial environment. Since the overburden pressure at the base of a flooded moulin is greater than that provided by ice, lake-outburst events seem capable of exerting sufficient upward force to lift the ice sheet locally, if water flow in the subglacial environment is constrained laterally. Considering a moulin with a 10 m2 cross-sectional area, basal pressurization can be maintained over lake-outburst episodes lasting hours to days.
Effects of antiagglomerants on the interactions between hydrate particles
Authors: Anklam Mark R. , York J. Dalton , Helmerich Luke , Firoozabadi Abbas
Published: December 2007

Hydrate inbibition in natural gas production by antiagglomeration is promising because of effectiveness at high subcoolings encountered in many offshore operations. There are various mechanisms that are believed to contribute to the repulsion and attraction of hydrate particles. These include: (1) steric, (2) dispersion, (3) capillary, and (4) shear forces. Some of the expressions derived, and some formulas are used from the literature to provide a theoretical analysis of the forces between two hydrate particles to examine antiagglomeration using surfactants. Results show that hydrate particle size has the most important effect on antiagglomeration. Results also show that the contact angle increase and the oil‐water interfacial tension decrease will either reduce capillary forces significantly or eliminate it. Effective antiagglomerants reduce the size, decrease interfacial tension, and increase contact angle through the water phase. © 2007 American Institute of Chemical Engineers AIChE J, 2008
Leak growth mechanism in composite Pd membranes prepared by the electroless deposition method
Authors: Guazzone Federico , Ma Yi Hua
Published: December 2007

The leak (of He gas) in composite Pd membranes prepared by the electroless deposition method was studied. The leak was distributed over the entire surface of membranes, and was due to the formation of pinholes, 0.1–2 μm in dia., located at the boundaries of Pd clusters and Pd crystallites. The rate at which the leak developed in H2 atmosphere was determined at 450, 500 and 550°C, and an apparent activation energy for the leak growth was calculated to be equal to 238 kJ/mol, which was close to the activation energy of Pd self‐diffusion coefficient of 266 kJ/mol. From experimental data at 450, 500 and 550°C, the leak rate increase at 400°C was extrapolated. In order to corroborate the calculated rate at 400°C, a 4 μm thick composite Pd membrane, M‐53, was studied for over 2,000 h in H2 atmosphere. M‐53 showed a H2 permeance of 42 m3/m2 h bar0.5, and an outstanding selectivity (H2/He) higher than 22,000 over 2,200 h, which was in agreement with the calculated leak rate increase at 400°C. © 2007 American Institute of Chemical Engineers AIChE J, 2008
Association study of two polymorphisms of the serotonin‐2A receptor gene and suicide attempts
Authors: Vaquero‐Lorenzo Concepcion , Baca‐Garcia Enrique , Diaz‐Hernandez Montserrat , Perez‐Rodriguez M. Mercedes , Fernandez‐Navarro Pablo , Giner Lucas , Carballo Juan J. , Saiz‐Ruiz Jeronimo , Fernandez‐Piqueras Jose , Baldomero Enrique Baca , de Leon Jose , Oquendo Maria A.
Published: December 2007

Serotonin (5‐HT) receptors may have a role in suicidal behavior. Previous studies have shown an association between the T102C polymorphism of the 5‐HT2a receptor gene and suicidal behavior. However, negative findings have also been reported. We examined the association between the T102C and C1354T (His452Tyr) polymorphisms of the 5‐HT2a receptor gene and suicide attempts. Four hundred forty‐one suicide attempters, 339 psychiatric patients, and 410 healthy controls were compared for genotypes of the T102C and C1354T (His452Tyr) polymorphisms. There were significant differences in the distribution of the three genotypes (TT, TC, and CC) of the T102C polymorphism in the three groups (controls, psychiatric patients, and suicide attempters). There was an excess of C/C genotypes in the suicide attempter group compared with the control group, but there were no significant differences between suicide attempters and psychiatric controls. We found no association between the C1354T polymorphism and suicide attempts. The C allele of the T102C polymorphism of the 5‐HT2A receptor gene may be associated with biological susceptibility for suicidal behavior or psychiatric conditions. © 2007 Wiley‐Liss, Inc.
New functional single nucleotide polymorphism (Ala72Ser) in the COMT gene is associated with aggressive behavior in male schizophrenia
Authors: Hong Jin Pyo , Lee Joongsun S. , Chung Seockhoon , Jung Jaeyeul , Yoo Hanik K. , Chang Sung Man , Kim Chang Yoon
Published: December 2007

A new functional single nucleotide polymorphism (SNP) Ala72Ser in the COMT gene was discovered recently. The purpose of our study is to examine the association between Ala72Ser and Val158Met functional polymorphisms in COMT gene and homicidal behavior in schizophrenia. DNA was genotyped for the Ala72Ser and Val158Met SNPs of the COMT gene in a sample of 93 schizophrenic patients who committed homicide (H‐SCZ) and 100 schizophrenic patients who had never committed homicide (NH‐SCZ). A statistically significant difference was found in genotype distribution and allele frequencies in SNP Ala72Ser of COMT gene between H‐SCZ and NH‐SCZ group. In haplotype analysis, the frequency of the combination of high‐high activity allele (Ala‐Val) was lower in H‐SCZ group than in NH‐SCZ group (P = 0.000069). Our study showed a highly significant association between a COMT haplotype of two functional SNPs and aggressive behavior in schizophrenia. © 2007 Wiley‐Liss, Inc.
Family‐based SNP association study on 8q24 in bipolar disorder
Authors: Zandi Peter P. , Zöllner Sebastian , Avramopoulos Dimitrios , Willour Virginia L. , Chen Yi , Qin Zhaohui S. , Burmeister Margit , Miao Kuangyi , Gopalakrishnan Shyam , McEachin Richard , Potash James B. , DePaulo J. Raymond , McInnis Melvin G.
Published: December 2007

Previous linkage studies have identified chromosome 8q24 as a promising positional candidate region to search for bipolar disorder (BP) susceptibility genes. We, therefore, sought to identify BP susceptibility genes on chromosome 8q24 using a family‐based association study of a dense panel of SNPs selected to tag the known common variation across the region of interest. A total of 1,458 SNPs across 16 Mb of 8q24 were examined in 3,512 subjects, 1,954 of whom were affected with BP, from 737 multiplex families. Single‐locus tests were carried out with FBAT and Geno‐PDT, and multi‐locus test were carried out with HBAT and multi‐locus Geno‐PDT. None of the SNPs were associated with BP in the single‐locus tests at a level that exceeded our threshold for study‐wide significance (P < 3.00 × 10−5). However, there was consistent evidence at our threshold for the suggestive level (P < 7.00 × 10−4) from both the single locus and multi‐locus tests of associations with SNPs in the genes ADCY8, ST3GAL1, and NSE2. Multi‐locus analyses suggested joint effects between ADCY8 and ST3GAL1 (P = 3.00 × 10−4), with at least one copy of the “high risk” allele required at both genes for association with BP, consistent with a jointly dominant–dominant model of action. These findings with ADCY8 and ST3GAL1 warrant further investigation in order to confirm the observed associations and their functional significance for BP susceptibility. © 2007 Wiley‐Liss, Inc.
Association study between the serotonin 1A receptor (HTR1A) gene and neuroticism, major depression, and anxiety disorders
Authors: Hettema J.M. , An S.S. , van den Oord E.J.C.G , Neale M.C. , Kendler K.S. , Chen X.
Published: December 2007

The serotonin neurotransmitter system in general, and the serotonin 1A receptor in particular, has been broadly implicated in the pathophysiology of mood and anxiety disorders, although the results of genetic association studies have been mixed. In this study, we examined the serotonin 1A receptor gene, HTR1A, for its association with shared genetic risk across a range of anxiety and depression‐related phenotypes. Using multivariate structural equation modeling, we selected twin pairs from the population‐based Virginia Adult Twin Study of Psychiatric and Substance Use Disorders scoring at the extremes of a latent genetic risk factor that underlies susceptibility to neuroticism, major depression, and several anxiety disorders. One member from each selected pair was entered into a 2‐stage, case‐control association study for the HTR1A gene. In the resulting sample of 589 cases and 539 controls, four SNPs spanning the HTR1A locus, including the C(−1019)G functional promoter polymorphism (rs6295), were screened in stage 1, the positive results of which were tested for replication in stage 2. While one marker met threshold significance criteria in stage 1, this association was not replicated in stage 2. Post‐hoc analyses did not reveal association to any of the specific psychiatric phenotypes. Our data suggests that the HTR1A gene may not play a major role in the genetic susceptibility underlying depressive and anxiety‐related phenotypes. © 2007 Wiley‐Liss, Inc.
Two methylenetetrahydrofolate reductase gene (MTHFR) polymorphisms, schizophrenia and bipolar disorder: An association study
Authors: Jönsson Erik G , Larsson Kristina , Vares Maria , Hansen Thomas , Wang August G. , Djurovic Srdjan , Rønningen Kjersti S. , Andreassen Ole A. , Agartz Ingrid , Werge Thomas , Terenius Lars , Hall Håkan
Published: December 2007

Recent meta‐analyses of the methylenetetrahydrofolate reductase gene (MTHFR) have suggested association between two of its functional single gene polymorphisms (SNPs; C677T and A1298C) and schizophrenia. Studies have also suggested association between MTHFR C677T and A1298C variation and bipolar disorder. In a replication attempt the MTHFR C677T and A1298C SNPs were analyzed in three Scandinavian schizophrenia case‐control samples. In addition, Norwegian patients with bipolar disorder were investigated. There were no statistically significant allele or genotype case‐control differences. The present Scandinavian results do not verify previous associations between the putative functional MTHFR gene polymorphisms and schizophrenia or bipolar disorder. However, when combined with previous studies in meta‐analyses there is still evidence for association between the MTHFR C677T polymorphism and schizophrenia. Additional studies are warranted to shed further light on these relationships. © 2007 Wiley‐Liss, Inc.
Replication of linkage with bipolar disorder on chromosome 16p in the eastern Quebec population
Authors: Mérette Chantal , Roy Marc‐André , Bureau Alexandre , Fournier Alain , Émond Claudia , Cliche Denis , Jomphe Valérie , Chagnon Yvon C. , Maziade Michel
Published: December 2007

In a previous study [Maziade et al. (2005); Mol Psychiatry 10:486–499], we provided evidence for linkage (parametric lod score of 4.05) on chromosome 16p for bipolar affective disorder (BP) in 21 kindreds from Eastern Quebec, a population characterized by a founder effect. Using a stringent design, we performed a replication study in a second sample of 27 kindreds (sample 2) collected from the same population and assessed with the same methodologies as in our original sample (sample 1), that is with the same diagnostic procedure and using a common set of 23 markers studied with model‐based (parametric) and model‐free (nonparametric) linkage analyses. We replicated our initial finding with P values <0.001. Indeed, maximum NPLall scores of 3.7 and 3.52 were found at marker D16S3060 in sample 2 for the narrow and broad BP phenotype definition, respectively. For the latter definition, the nonparametric score reached 3.87 in the combined sample, a value that exceeded the maximum NPL score obtained in each individual sample (NPLall = 2.32 in sample 1; NPLall = 3.52 in sample 2). Moreover, a refined phenotype restricted to BP associated with psychosis yielded significant evidence for linkage in each individual sample (NPLall = 2.38 in sample 1; NPLall = 2.72) while yielding the best result (NPLall score = 3.90) in the combined sample (samples 1 and 2), despite an important reduction in the number of affected individuals. It is also noteworthy that the use of the refined phenotype provided a location of the maximum linkage peak shared by both samples, that is, at marker D16S668 in 16p13.12, suggesting consistency across samples. Our study provided one of the strongest pieces of evidence for linkage with BP in 16p and illustrated the heuristic potential of a replication study in a second sample ascertained from the same population and using homogeneous methodologies. © 2007 Wiley‐Liss, Inc.
Study on GRIA2, GRIA3 and GRIA4 genes highlights a positive association between schizophrenia and GRIA3 in female patients
Authors: Magri Chiara , Gardella Rita , Valsecchi Paolo , Barlati Stefano Davide , Guizzetti Luca , Imperadori Laura , Bonvicini Cristian , Tura Gian Battista , Gennarelli Massimo , Sacchetti Emilio , Barlati Sergio
Published: December 2007

Impairment of glutamatergic neurotransmission is one of the major hypotheses proposed to explain the neurobiology of schizophrenia. Therefore, the genes involved in the glutamate neurotransmitter system could be considered potential candidate genes for schizophrenia susceptibility. A systematic study on alpha‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole‐propionic acid (AMPA) receptor genes has been carried out and the results obtained from the analysis on GRIA2, GRIA3 and GRIA4 are reported. No evidence of association with schizophrenia was found for the GRIA2 and GRIA4 genes; strong evidence of association with schizophrenia was found for GRIA3. This X‐linked gene showed a different behavior in the two genders; a positive association with schizophrenia was observed among females but not in males. Female carriers of rs1034428 A allele were found to have a 2.19‐fold higher risk of developing schizophrenia compared to non‐carriers and 3.28‐fold higher risk for developing a non‐paranoid phenotype. The analysis at the haplotype level showed that susceptibility to schizophrenia was associated with the specific haplotype rs989638–rs1034428–rs2227098 CAC (P = 0.0008). We conclude that, of the three AMPA genes analyzed here, only GRIA3 seems to be involved in the pathogenesis of schizophrenia, but only in females. © 2007 Wiley‐Liss, Inc.
Associations of ATF4 gene polymorphisms with schizophrenia in male patients
Authors: Qu Mei , Tang Fulei , Wang Lifang , Yan Hao , Han Yonghua , Yan Jun , Yue Weihua , Zhang Dai
Published: December 2007

Activating transcription factor 4 (ATF4) is considered as a positional candidate gene for schizophrenia due to its location at chromosome 22q13, a region linked to schizophrenia. Furthermore, as protein interaction partner of ATF4, disrupted in schizophrenia 1 (DISC1) and its signal pathway implicated in the pathophysiology of schizophrenia have been widely supported by a number of genetic and neurobiological studies. Our aim was to investigate whether ATF4 is associated with schizophrenia in case–control samples of Han Chinese subjects consisting of 352 schizophrenia patients and 357 healthy controls. We detected 18 single nucleotide polymorphisms (SNPs) in ATF4 locus, two of which were analyzed, including one insertion at the putative core promoter region (rs17001266, –/C) and one nonsynonymous variant in exon 1 (rs4894, C/A, Pro22Gln). Allele distributions of two SNPs showed significant associations with schizophrenia in male subjects (respectively, rs17001266: P = 0.021, OR = 1.58, 95% CI = 1.07–2.33; rs4894: P = 0.004, OR = 1.78, 95% CI = 1.19–2.67), but not in female subjects as well as the entire population. Two haplotypes CC and ‐A constructed of rs17001266–rs4894 also revealed significant associations with schizophrenia in male group (global P = 0.0097). These findings support that ATF4 gene may be involved in susceptibility to schizophrenia with sex‐dependent effect in the Chinese Han population and suggest that further functional assays are needed to verify their relevance to the pathogenesis of schizophrenia. © 2007 Wiley‐Liss, Inc.
Association of the dopamine transporter gene and ADHD symptoms in a Canadian population‐based sample of same‐age twins
Authors: Ouellet‐Morin Isabelle , Wigg Karen G. , Feng Yu , Dionne Ginette , Robaey Philippe , Brendgen Mara , Vitaro Frank , Simard Louise , Schachar Russell , Tremblay Richard E. , Pérusse Daniel , Boivin Michel , Barr Cathy L.
Published: December 2007

Attention deficit hyperactivity disorder (ADHD) is the most prevalent psychiatric disorder emerging during childhood. Psychostimulant medications (e.g., methylphenidate) noticeably reduce ADHD symptoms in most children. Since methylphenidate inhibits dopamine transporter activity, the dopamine transporter gene (DAT1) was considered to be the prime candidate risk gene in ADHD. Several studies found evidence for an association between the 10‐repeat allele of the variable number of tandem repeat (VNTR) located in the 3′ untranslated region and ADHD and/or ADHD symptoms in clinical and population‐based samples. However, this finding was not replicated in all samples. In this study, we investigated the association between the DAT1 gene and ADHD symptoms in a population‐based twin sample from Québec (Canada). We used two polymorphisms, the VNTR and rs27072, the last providing the most significant results in a clinical sample from Toronto (Ontario, Canada). No association was noted between the VNTR and ADHD symptoms in children at 6 and 7 years of age, as reported by teachers. However, a significant association was found for the rs27072 polymorphism and symptoms of inattention and hyperactivity/impulsivity. These findings indicate that the DAT1 gene contributes to ADHD symptoms in this sample and further suggest that the VNTR may not be the optimal polymorphism for study in all populations. © 2007 Wiley‐Liss, Inc.
Release study of alfuzosin hydrochloride loaded to novel hydrogel P(HEMA‐co‐AA)
Authors: Mohapatra R. , Ray D. , Swain A. K. , Pal T. K. , Sahoo P. K.
Published: December 2007

Hydrogels are of great interest in delivering drugs through their polymeric network. Hydrogels of macroporous copolymer 2‐hydroxy ethyl methacrylate (HEMA) with acrylic acid (AA) were prepared in the presence of N,N′‐methylene‐bis‐acrylamide as crosslinker and benzoyl peroxide as initiator. The structure of the copolymer, hydrogel character, and biodegradability have already been discussed in our previous article (Mohapatra et al., Polym Polym Compos 2005, 13, 807) entitled P(HEMA‐co‐AA) as Novel Biodegradable Macroporous Hydrogel. The current study involves the in vitro and in vivo release of alfuzosin hydrochloride at pH 7.0 and 9.2, taking different concentrations of drug and hydrogel. The percentage of drug entrapment study was done and the stability study was also performed according to I.C.H. guidelines for a period of 6 months giving satisfactory results. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Compatibility of liquid deproteinized natural rubber having epoxy group (LEDPNR)/poly (L‐lactide) blend
Authors: Nghia Phan Trung , Siripitakchai Niti , Klinklai Warunee , Saito Takayuki , Yamamoto Yoshimasa , Kawahara Seiichi
Published: December 2007

Reaction after mixing of liquid epoxidized natural rubber/poly(L‐lactide) blend was performed to enhance the compatibility of the blend. The liquid epoxidized natural rubber was prepared by epoxidation of deproteinized natural rubber with peracetic acid in latex stage followed by depolymerization with peroxide and propanal. The resulting liquid deproteinized natural rubber having epoxy group (LEDPNR) was mixed with poly(L‐lactide) (PLLA) to investigate the compatibility of the blend through differential scanning calorimetry, optical light microscopy, and NMR spectroscopy. After heating the blend at 473 K for 20 min, glass transition temperature (Tg) of LEDPNR in LEDPNR/PLLA blend increased from 251 to 259 K, while Tg and melting temperature (Tm) of PLLA decreased from 337 to 332 K and 450 to 445 K, respectively, suggesting that the compatibility of LEDPNR/ PLLA blend was enhanced by a reaction between the epoxy group of LEDPNR and the ester group of PLLA. The reaction was proved by high‐resolution solid‐state 13C NMR spectroscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Graft copolymerization of p‐acryloyloxybenzoic acid and p‐methacryloyloxybenzoic acid onto isotactic polypropylene and their thermal properties: Part I
Authors: Çetin S. , Tinçer T.
Published: December 2007

The polymerization and grafting of the monomers p‐acryloyloxybenzoic acid and p‐methacryloyloxybenzoic acid were studied. Poly(acryloyloxybenzoic acid) was obtained by γ‐radiation‐induced solution polymerization and bulk melt polymerization initiated by dicumyl peroxide. Poly(methacryloyloxybenzoic acid) could be obtained only by bulk melt polymerization. The graft copolymerization of the monomers onto isotactic polypropylene was carried out in bulk. The maximum grafting was reached in shorter times at higher temperatures, and it also increased with the concentration of the monomers in the reaction medium. The thermal and crystallization behavior of the graft copolymers was studied with differential scanning calorimetry and wide‐angle X‐ray diffraction. The graft copolymerization of p‐acryloyloxybenzoic acid did not have any influence on the formation of both α forms (monoclinic) of polypropylene, whereas p‐methacryloyloxybenzoic acid led to the α2 form. The β‐crystalline modification (hexagonal) formed in poly(acryloyloxybenzoic acid)‐g‐polypropylene products at 185°C and at higher grafting temperatures and also in the second run of differential scanning calorimetry studies after fast cooling. The β form was not observed in graft copolymers of poly(methacryloyloxybenzoic acid). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Polyaniline–rhodium composites: Preparation, physicochemical characterization, and catalytic properties
Authors: Stochmal Edyta , Hasik Magdalena , Adamczyk Anna , Bernasik Andrzej , Turek Wincenty , Sniechota Agnieszka
Published: December 2007

In this work, polyaniline (PANI)–rhodium composites have been obtained for the first time. Their preparation procedure has involved reduction of Rh3+ ions in RhCl3 aqueous solutions with NaBH4 in the presence of PANI. Using UV–vis spectroscopy, it has been found that the reduction process is fast. X‐ray diffraction and Rh3d XPS studies have confirmed that metallic rhodium is incorporated into PANI matrix. SEM and TEM investigations allowed to establish that the sizes of Rh crystallites formed depend on the amount of metal in the composite as well as on the preparation conditions. It has been demonstrated that the composites containing Rh nanoparticles whose size is predominantly below 10 nm can be obtained. IR spectroscopy has proved that PANI chain is protonated in the Rh3+ reduction process. Catalytic properties of PANI–Rh composites have been investigated using isopropyl alcohol conversion as the test reaction. It has been found that the composites containing Rh nanoparticles show high redox activity. Catalytic activity of the composites in which larger, agglomerated metal particles have been present is about three times lower. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Evaluation of surface free energy for PMMA films
Authors: Ozcan Canturk , Hasirci Nesrin
Published: December 2007

Surface free energy (SFE) is a property resulted from the chemical structure and the orientation of the molecules at the surface boundary of the materials. For solids, it can be calculated from the contact angles of liquid drops with known surface tension, formed on the solid surface. There are various SFE evaluation methods based on different theoretical assumptions. In this study, SFE and the dispersive, polar, acidic and basic components of the SFE of a polymeric material, poly(methyl methacrylate) (PMMA), were calculated by using Zisman, Saito, Fowkes, Berthelot, Geometric mean, Harmonic mean, and Acid–base approaches. The results obtained from various liquid couples or triplets were compared. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Comparison of two acetylcholinesterase gene cDNAs of the lesser mealworm,Alphitobius diaperinus, in insecticide susceptible and resistant strains
Authors: Kozaki Toshinori , Kimmelblatt Brian A. , Hamm Ronda L. , Scott Jeffrey G.
Published: December 2007

Two cDNAs encoding different acetylcholinesterase (AChE) genes (AdAce1andAdAce2) were sequenced and analyzed from the lesser mealworm,Alphitobius diaperinus. BothAdAce1andAdAce2were highly similar (95 and 93% amino acid identity, respectively) with theAcegenes ofTribolium castaneum. BothAdAce1andAdAce2have the conserved residues characteristic of AChE (catalytic triad, intra‐disulfide bonds, and so on). Partial cDNA sequences of theAlphitobius Acegenes were compared between two tetrachlorvinphos resistant (Kennebec and Waycross) and one susceptible strain of beetles. Several single nucleotide polymorphisms (SNPs) were detected, but only one non‐synonymous mutation was found (A271S inAdAce2). No SNPs were exclusively found in the resistant strains, the A271S mutation does not correspond to any mutations previously reported to alter sensitivity of AChE to organophosphates or carbamates, and the A271S was found only as a heterozygote in one individual from one of the resistantA. diaperinusstrains. This suggests that tetrachlorvinphos resistance in the Kennebec and Waycross strains ofA. diaperinusis not due to mutations in either AChE gene. The sequences ofAdAce1andAdAce2provide new information about the evolution of these important genes in insects. Arch Insect Biochem Physiol. © 2007 Wiley‐Liss, Inc.
Purification and characterization of two cysteine peptidases of the Mediterranean fruit fly Ceratitis capitata during metamorphosis
Authors: Rabossi Alejandro , Stoka Veronika , Puizdar Vida , Turk Vito , Quesada‐Allué Luis A.
Published: December 2007

In holometabolous insects, there is a complete body remodeling from larva to adult. We determined in Ceratitis capitata that the transition from pre‐pupa to pupa, 40 to 48 h after puparium formation (h APF), is a key moment of metamorphosis; when salivary glands, intestine, fat body, and muscles are in different stages of cell death. At 44–46 h APF, muscles from segments 1–3 (thoracic region) appeared fully disintegrated, whereas posterior muscles just started death processes. To understand some of the biochemical events eventually involved in histolytic processes during early metamorphosis, two cysteine peptidases coined “Metamorphosis Associated Cysteine Peptidase” (MACP‐I and MACP‐II) were purified to homogeneity from 40–46‐h APF insects. Both enzymes were inhibited by Ep‐475, a specific inhibitor of papain‐like cysteine‐peptidases. MACP‐I is a single chain protein with an apparent molecular mass of 80 kDa and includes several isoforms with pI values of pH 6.25–6.35, 6.7, and 7.2. The enzyme has an optimum pH of 5.0 and its pH stability ranges from pH 4.0 to 6.0. The molecular weight and N‐terminal sequence suggest that MACP‐I might be a novel enzyme. MACP‐II is an acidic single chain protein with a pI of pH 5.85 and an apparent molecular mass of 30 kDa. The enzyme is labile with a maximum stability in the pH range of 4.0 to 6.0 and an optimum pH among 5.0 to 6.0. MAPCP‐II characteristics suggest it is a cathepsin B‐like enzyme. Arch. Insect Biochem. Physiol. © 2007 Wiley‐Liss, Inc.
Differentially regulated expression of growth differentiation factor 5 and bone morphogenetic protein 7 in articular cartilage and synovium in murine chronic arthritis: Potential importance for cartilage breakdown and synovial hypertrophy
Authors: Bobacz Klaus , Sunk Ilse‐Gerlinde , Hayer Silvia , Amoyo Love , Tohidast‐Akrad Makiyeh , Kollias George , Smolen Josef S. , Schett Georg
Published: December 2007

Objective

To examine whether the endogenous expression of growth differentiation factor 5 (GDF‐5) and bone morphogenetic protein 7 (BMP‐7) is altered in the cartilage and synovium of human tumor necrosis factor α (TNFα)–transgenic (hTNFtg) mice with chronic arthritis, and to investigate the response of hTNFtg chondrocytes as well as fibroblast‐like synoviocytes (FLS) to these morphogens in vitro.

Methods

Analyses were performed in hTNFtg mice with chronic destructive arthritis and in wild‐type (WT) mice as controls. Expression of GDF‐5 and BMP‐7 in the articular cartilage and synovium was examined by real‐time polymerase chain reaction and immunohistochemistry. Human TNFtg cartilage explants, chondrocytes, and FLS monolayer cultures were assessed for basal matrix biosynthesis as well as growth factor responsiveness, using 35S‐sulfate incorporation assays. In addition, the DNA content/cell proliferation rate was measured.

Results

The expression of GDF‐5 and BMP‐7 was decreased in articular cartilage from hTNFtg mice, whereas expression of both morphogens was increased in arthritic synovium from hTNFtg mice, as compared with the levels in WT controls. Isotope incorporation revealed a marked reduction of matrix synthesis in hTNFtg cartilage as well as a decrease in responsiveness to GDF‐5 and BMP‐7. The DNA content did not change in arthritic cartilage as compared with WT cartilage. In hTNFtg FLS, growth factor stimulation increased the rate of cell proliferation and the production of extracellular matrix.

Conclusion

In this murine model of TNFα‐mediated arthritis, the expression of GDF‐5 and BMP‐7 is regulated differentially in articular cartilage and synovium. In articular cartilage, the down‐regulation of GDF‐5 and BMP‐7, which function to maintain matrix integrity, could potentially compromise tissue repair, whereas in synovium, the increased expression of GDF‐5 and BMP‐7 might contribute to synovial hypertrophy.
Intravenous immunoglobulins for relapses of systemic vasculitides associated with antineutrophil cytoplasmic autoantibodies: Results of a multicenter, prospective, open‐label study of twenty‐two patients
Authors: Martinez Valérie , Cohen Pascal , Pagnoux Christian , Vinzio Stéphane , Mahr Alfred , Mouthon Luc , Sailler Laurent , Delaunay Claire , Sadoun Alain , Guillevin Loïc ,   French Vasculitis Study Group
Published: December 2007

Objective

To evaluate at 9 months and 24 months the safety and efficacy of intravenous immunoglobulins (IVIGs) administered for 6 months to treat relapses of Wegener's granulomatosis (WG) or microscopic polyangiitis (MPA) occurring either under treatment or during the year following discontinuation of corticosteroids and/or immunosuppressants.

Methods

Patients received IVIGs (0.5 gm/kg/day for 4 days) as additional therapy administered monthly for 6 months and were assessed every 3–6 months. Corticosteroids could be maintained or reintroduced at the time of relapse; immunosuppressants could be continued but could not be reintroduced. At months 9 (end point) and 24 (followup), the following information was collected: complete or partial remission, relapse as assessed with the Birmingham Vasculitis Activity Score (BVAS) 2005, and tolerance and safety of IVIG therapy.

Results

Twenty‐two Caucasian patients (7 men and 15 women) were studied: 19 had WG, and 3 had MPA. Their median age was 53 years (range 19–75 years), and their median duration of systemic vasculitis was 27 months (range 7–109 months). Their median BVAS 2005 score was 11 (range 3–25). At study entry, 21 patients were ANCA positive, and 21 patients were taking steroids and/or immunosuppressants. All patients experiencing relapse were treated with the same drug(s) plus IVIGs. All patients initially responded to IVIG therapy. By month 9, 13 patients had complete remission, 1 had partial remission, 7 had relapse, and 1 had treatment failure. In 8 of the 14 patients who had remission, the response persisted at month 24. Seven patients experienced minor side effects.

Conclusion

IVIGs induced complete remissions of relapsed ANCA‐associated vasculitides in 13 of 22 patients at month 9. Because of the good safety and tolerance profiles of IVIGs, these agents can be included in a therapeutic strategy with other drugs used to treat relapses of WG or MPA.
Differences in synovial tissue infiltrates between anti–cyclic citrullinated peptide–positive rheumatoid arthritis and anti–cyclic citrullinated peptide–negative rheumatoid arthritis
Authors: van Oosterhout M. , Bajema I. , Levarht E. W. N. , Toes R. E. M. , Huizinga T. W. J. , van Laar J. M.
Published: December 2007

Objective

To compare synovial tissue infiltrates from patients with anti–cyclic citrullinated peptide (anti‐CCP)–positive rheumatoid arthritis (RA) with those from patients with anti‐CCP–negative RA.

Methods

Synovial tissue samples were obtained arthroscopically from the inflamed knee joints of 57 patients with RA (34 of whom were anti‐CCP positive) and examined for several histologic features along with immunohistologic expression of cell markers. Joint damage was assessed using the Kellgren/Lawrence (K/L) scale (range 0–4) on standard anteroposterior radiographs. In 31 patients (18 of whom were anti‐CCP positive), synovial tissue was available from an earlier time point, allowing analysis of temporal changes.

Results

Synovial tissue from anti‐CCP–positive patients was characterized by a higher mean number of infiltrating lymphocytes (61.6 versus 31.4/high‐power field [hpf] [400×]; P = 0.01), less extensive fibrosis (mean score of 1.2 versus 2.0; P = 0.04), and a thinner synovial lining layer (mean score of 2.1 versus 3.3; P = 0.002) compared with synovial tissue from anti‐CCP–negative patients. Anti‐CCP–positive patients expressed more CD3, CD8, CD45RO, and CXCL12. More anti‐CCP–positive patients had a K/L score >1 compared with anti‐CCP–negative patients. The difference in the mean lymphocyte counts was already present a mean of 3.8 years before the index biopsy (76.7 lymphocytes/hpf and 26.7 lymphocytes/hpf in anti‐CCP–positive patients and anti‐CCP–negative patients, respectively; P = 0.008) and was independent of disease duration and K/L score.

Conclusion

Synovitis in patients with anti‐CCP–positive RA differs from that in patients with anti‐CCP– negative RA, notably with respect to infiltrating lymphocytes, and is associated with a higher rate of local joint destruction.
Engineered cartilage generated by nasal chondrocytes is responsive to physical forces resembling joint loading
Authors: Candrian C. , Vonwil D. , Barbero A. , Bonacina E. , Miot S. , Farhadi J. , Wirz D. , Dickinson S. , Hollander A. , Jakob M. , Li Z. , Alini M. , Heberer M. , Martin I.
Published: December 2007

Objective

To determine whether engineered cartilage generated by nasal chondrocytes (ECN) is responsive to different regimens of loading associated with joint kinematics and previously shown to be stimulatory of engineered cartilage generated by articular chondrocytes (ECA).

Methods

Human nasal and articular chondrocytes, harvested from 5 individuals, were expanded and cultured for 2 weeks into porous polymeric scaffolds. The resulting ECN and ECA were then maintained under static conditions or exposed to the following loading regimens: regimen 1, single application of cyclic deformation for 30 minutes; regimen 2, intermittent application of cyclic deformation for a total of 10 days, followed by static culture for 2 weeks; regimen 3, application of surface motion for a total of 10 days.

Results

Prior to loading, ECN constructs contained significantly higher amounts of glycosaminoglycan (GAG) and type II collagen compared with ECA constructs. ECN responded to regimen 1 by increasing collagen and proteoglycan synthesis, to regimen 2 by increasing the accumulation of GAG and type II collagen as well as the dynamic modulus, and to regimen 3 by increasing the expression of superficial zone protein, at the messenger RNA level and the protein level, as well as the release of hyaluronan. ECA constructs were overall less responsive to all loading regimens, likely due to the lower extracellular matrix content.

Conclusion

Human ECN is responsive to physical forces resembling joint loading and can up‐regulate molecules typically involved in joint lubrication. These findings should prompt future in vivo studies exploring the possibility of using nasal chondrocytes as a cell source for articular cartilage repair.
Regional differences in chondrocyte metabolism in osteoarthritis: A detailed analysis by laser capture microdissection
Authors: Fukui Naoshi , Ikeda Yasuko , Ohnuki Toshiyuki , Tanaka Nobuho , Hikita Atsuhiko , Mitomi Hiroyuki , Mori Toshihito , Juji Takuo , Katsuragawa Yozo , Yamamoto Seizo , Sawabe Motoji , Yamane Shoji , Suzuki Ryuji , Sandell Linda J. , Ochi Takahiro
Published: December 2007

Objective

To determine the change in metabolic activity of chondrocytes in osteoarthritic (OA) cartilage, considering regional difference and degree of cartilage degeneration.

Methods

OA cartilage was obtained from knee joints with end‐stage OA, at both macroscopically intact areas and areas with various degrees of cartilage degeneration. Control cartilage was obtained from age‐matched donors. Using laser capture microdissection, cartilage samples were separated into superficial, middle, and deep zones, and gene expression was compared quantitatively in the respective zones between OA and control cartilage.

Results

In OA cartilage, gene expression changed markedly with the site. The expression of cartilage matrix genes was highly enhanced in macroscopically intact areas, but the enhancement was less obvious in the degenerated areas, especially in the upper regions. In contrast, in those regions, the expression of type III collagen and fibronectin was most enhanced, suggesting that chondrocytes underwent a phenotypic change there. Within OA cartilage, the expression of cartilage matrix genes was significantly correlated with SOX9 expression, but not with SOX5 or SOX6 expression. In OA cartilage, the strongest correlation was observed between the expression of type III collagen and fibronectin, suggesting the presence of a certain link(s) between their expression.

Conclusion

The results of this study revealed a comprehensive view of the metabolic change of the chondrocytes in OA cartilage. The change of gene expression profile was most obvious in the upper region of the degenerated cartilage. The altered gene expression at that region may be responsible for the loss of cartilage matrix associated with OA.