bluuebunny/crossref_metadata_2025_split huggingface dataset:
in vitro Evaluation of Biodegradable Poly(butylene succinate) as a Novel Biomaterial
Authors: Li Haiyan , Chang Jiang , Cao Amin , Wang Junying 
Published: May 2005

AbstractSummary: Poly(butylene succinate) (PBSU) can be easily synthesized by condensation polymerization of the starting materials of succinic acid and butan‐1,4‐diol. It has good degradability and possesses excellent processability. Due to these advantages, PBSU was first evaluated in the present study for its potential application as a novel biomaterial. The in vitro biocompatibility of the PBSU was evaluated by monitoring proliferation and differentiation of osteoblasts cultured on the PBSU film substrates for different periods. The results showed that the PBSU was biocompatible as the osteoblasts could proliferate and differentiate on the PBSU plates. In addition, the hydrolytic degradation behavior of the PBSU films in the phosphate‐buffered saline (PBS) was also investigated and the results suggested that the PBSU degraded in the PBS solution with the same behavior as that of the degradable poly(α‐hydroxyesters). In addition to the biocompatibility and hydrolytic degradation, some physical properties, including hydrophilicity, and mechanical and thermal properties of the PBSU substrates, were also determined and the results revealed that the PBSU was hydrophilic and ductile with excellent processability. The biocompatibility of the PBSU, together with the advantages of hydrolytic degradability, hydrophilicity, and excellent processability, indicated that PBSU has the potential to be used as a biomaterial for tissue repair.Alkaline phosphate activity of osteoblasts cultured on PBSU and TCPS substrates for different time periods.magnified imageAlkaline phosphate activity of osteoblasts cultured on PBSU and TCPS substrates for different time periods.
Biomolecular Hybrid of a Conducting Polymer with DNA: Morphology, Structure, and Doping Behavior
Authors: Dawn Arnab , Nandi Arun K. 
Published: May 2005

AbstractSummary: A poly(o‐methoxyaniline) (POMA)/DNA [weight fraction of DNA (WDNA) = 0.45] hybrid was prepared by mixing their solutions in sterilized double distilled water. The solution turned green upon aging for a longer time, and the doping of POMA by DNA was complete after about 15 d of aging. The doping was confirmed from the UV‐vis spectra where the 599 nm peak of POMA(EB) disappeared and a new peak for a π to localized polaron band‐transition appeared. With increasing aging time the new peak gradually shifted from 674 nm at 3 h to 820 nm at 15 d of mixing and thereafter it remained constant. The absence of a free carrier tail in the UV‐vis spectra indicated a coiled structure of POMA in the complex. Circular dichroism spectra of the hybrid solution indicated that the DNA conformation (double helical structure) remained unchanged in the hybrid. The SEM micrograph of the freeze–dried hybrid showed a needle‐like morphology of the DNA dispersed in a polymer matrix and it was completely different from the fibrillar network morphology of pure DNA in the solid state. The TEM micrograph indicated a homogeneous dispersion of DNA fibrils in the POMA matrix. The melting temperature of the POMA–DNA hybrid showed an increase compared to that of pure DNA by 5 °C, probably caused by an electrostatic interaction between the DNA anion and the POMA radical cation generated in the doping process. WAXS investigations revealed that the DNA crystal structure remained unchanged in the hybrid whereas the POMA crystal structure might be lost. An FT‐IR study suggested that interaction occurred between the phosphoric acid group of DNA and a nitrogen atom of POMA through proton transfer from the OH group of the former. A schematic model of the POMA–DNA complex randomly anchoring POMA chains with the DNA molecule was proposed. The dc conductivity of the POMA–DNA complex was found to be ca. 10−7 S · cm−1. Hence, this work describes a procedure for making a DNA‐conducting polymer hybrid without changing the conformation and structure of DNA.
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pH Effects on the Complexation, Miscibility and Radiation‐Induced Crosslinking in Poly(acrylic acid)‐Poly(vinyl alcohol) Blends
Authors: Nurkeeva Zauresh S. , Mun Grigoriy A. , Dubolazov Artem V. , Khutoryanskiy Vitaliy V. 
Published: May 2005

AbstractSummary: The effect of pH on the complexation of poly(acrylic acid) with poly(vinyl alcohol) in aqueous solution, the miscibility of these polymers in the solid state and the possibility for crosslinking the blends using gamma radiation has been studied. It is demonstrated that the complexation ability of poly(vinyl alcohol) with respect to poly(acrylic acid) is relatively low in comparison with some other synthetic non‐ionic polymers. The precipitation of interpolymer complexes was observed below the critical pH of complexation (pHcrit1), which characterizes the transition between a compact hydrophobic polycomplex and an extended hydrophilic interpolymer associate. Films prepared by casting from aqueous solutions at different pH values exhibited a transition from miscibility to immiscibility at a certain critical pH, pHcrit2, above which hydrogen bonding is prevented. It is shown here that gamma radiation crosslinking of solid blends is efficient and only results in the formation of hydrogel films for blends prepared between pHcrit1 and pHcrit2. The yield of the gel fraction and the swelling properties of the films depended on the absorbed radiation dose and the polymer ratio.SEM image of an equimolar PAA‐PVA blend cast from a pH 4.6 solution.magnified imageSEM image of an equimolar PAA‐PVA blend cast from a pH 4.6 solution.
Novel Alginate‐Poly(L‐histidine) Microcapsules as Drug Carriers: In Vitro Protein Release and Short Term Stability
Authors: Wang Shi‐Bin , Xu Fei‐Hai , He Hong‐Shan , Weng Lian‐Jin 
Published: May 2005

AbstractSummary: Spherical, smooth‐surfaced and mechanically stable alginate‐poly(L‐histidine) (PLHis) microcapsules with narrow particle size distributions were prepared by incubating calcium alginate beads in aqueous solutions of PLHis. The in vitro release characteristics, drug loading and encapsulation efficiency of the microcapsules were investigated using bovine erythrocytes hemoglobin (Hb) as a model drug. The results showed that the concentration of Ca2+ ions had a considerable effect on the drug loading, encapsulation efficiency and in vitro release behavior of the microcapsules. When the concentration of CaCl2 in the PLHis solution was increased from 0 to 3.0% (w/v), the drug loading and encapsulation efficiency decreased significantly from 38.0 to 4.3% and from 92.9 to 8.0%, respectively, while the total cumulative release of Hb from microcapsules in phosphate buffered saline solution (PBS, pH 6.8) decreased from 96.2 to 72.8% in 24 h. No significant protein release was observed during 70 h of incubation in hydrochloric acid solution (pH 1.2). However, under neutral conditions (PBS, pH 6.8), the Hb was completely and stably released within 24–70 h. An explosion test showed that the stability of alginate‐PLHis microcapsules depended strongly on the concentration of PLHis and the calcium ions in solution.Microscopy photo of Hb‐loaded alginate‐PLHis microcapsules.magnified imageMicroscopy photo of Hb‐loaded alginate‐PLHis microcapsules.
Bovine mater‐like NALP9 is an oocyte marker gene
Authors: Dalbiès‐Tran Rozenn , Papillier Pascal , Pennetier Sophie , Uzbekova Svetlana , Monget Philippe 
Published: May 2005

AbstractWe have cloned and sequenced the bovine NALP9 cDNA, which contains a 2991 bp long open reading frame with 76% homology to its human counterpart. The putative 996 amino acids protein presents the domain organization typical of the Nacht, Leucine rich repeat and Pyrin domain containing (NALP) family that includes the maternal effect factor MATER. By reverse transcription coupled to polymerase chain reaction, we have analyzed expression of NALP9 in a panel of somatic and gonadic tissues and during in vitro preimplantation development. The transcript was detected exclusively in testis and ovary, and at a remarkably high level in the oocyte from antral follicles. NALP9 mRNA remained present after in vitro maturation and fertilization, and was detected in embryos, but transcription was not reactivated at the maternal to embryo transition. Thus NALP9 is characterized as a novel oocyte marker gene in cattle. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Full‐term development of mouse eggs transplanted with male pronuclei derived from round spermatids: The effect of synchronization between male and female pronucleus on embryonic development
Authors: Jiang Man‐Xi , Lei Zi‐Li , Ouyang Ying‐Chun , Zhu Zi‐Yu , Zheng Yue‐Liang , Sun Qing‐Yuan , Chen Da‐Yuan 
Published: May 2005

AbstractPronucleus transplanted mice have been produced, but their donor male pronuclei were derived from mature sperm and were completely synchronous with female pronuclei because both male and female pronuclei came from the same fertilized oocyte. The present study firstly produced male pronuclei by introducing round spermatids into enucleated mouse oocytes, then transferred the male pronuclei into mouse oocytes at three activation stages and finally compared the effect of three kinds of oocytes on the development of reconstructed embryos. Our results indicate that, in enucleated oocytes, mouse round spermatid nuclei can transform to male pronuclei in a higher proportion, and the synchronization between male and female pronucleus does not significantly influence the early cleavage but the later and full‐term development of reconstructed embryos. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Functional challenge affects aquaporin mRNA abundance in mouse blastocysts
Authors: Offenberg Hanne , Thomsen Preben Dybdahl 
Published: May 2005

AbstractThe aquaporins (AQPs) are a family of channel proteins that facilitate diffusion of water across cell membranes. Three members of the AQP family have been detected in the mouse blastocyst: AQP 3 and 8 are located in the basolateral domain and AQP 9 predominantly in the apical domain of the trophoblast cells. These are believed to be involved in facilitating the accumulation of fluid into the blastocyst cavity. We have investigated the ability of mouse embryos to regulate AQP gene expression in response to different treatments expected to affect the passage of water across the trophoblast cells using real‐time PCR. In the first experiment 8‐cell embryos were allowed to develop to blastocysts in media from 300 to 400 mOsm. Blastocyst formation was unaffected by media made hyperosmolar by glycerol, whereas blastocyst formation was significantly reduced in sucrose‐based 350 and 400 mOsm media. AQP 8 mRNA levels were reduced when embryos were cultured in glycerol‐based hyperosmolar media. The mRNA levels of AQP 3, 7, 9, and 11 were not significantly affected by hyperosmolar media. In the second experiment blastocysts were punctured (0 hr) and allowed to re‐expand. AQP mRNA levels were examined after 2, 6, and 10 hr. Compared to control embryos, the expression of AQP 3, 7, and 9 were upregulated after 2 hr. Upregulation was sustained only for AQP 9 and this was sustained up to 6 and 10 hr after puncture. In the third experiment we compared expression of AQPs between in vitro cultured and in vivo developed blastocysts. We found that in vitro culture resulted in lower levels of AQP 8, 9, and 11 compared to in vivo development. These experiments show that mouse embryos are capable of regulating AQP mRNA abundances in response to environmental alterations. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
Identification of the bull sperm p80 protein as a PH‐20 ortholog and its modification during the epididymal transit
Authors: Morin Guillaume , Lalancette Claudia , Sullivan Robert , Leclerc Pierre 
Published: May 2005

AbstractWe have identified an 80 kDa protein in ejaculated bull spermatozoa (p80) which is found in acrosomal and post‐acrosomal areas of the head. It has a hyaluronidase activity and shares homologies with PH‐20, a sperm surface glycoprotein involved in sperm–egg interaction. The aim of the present study was to characterize bull sperm p80 protein at the nucleic and amino acid levels to determine whether it is the bovine PH‐20 ortholog. The complete nucleotide sequence determined by RT‐PCR, 3′ and 5′ RACE show that bull p80, displays identity with the PH‐20 nucleotide and amino acid sequences. Messenger RNA and protein expressions determined by Northern blot and immunohistochemistry revealed that the protein is testicular (expressed in spermatocytes and spermatids). The localization of p80 on spermatozoa, determined by indirect immunofluorescence using a monoclonal antibody, shows the protein in acrosomal and post acrosomal areas of the head with an increase in the signal intensity as sperm progress through the epididymis. Post‐translational modifications of the protein were investigated during the epididymal maturation by Western blot on protein extracts from sperm collected in the caput, corpus and cauda portions of bull epididymis. Glycolysation status of sperm p80 protein on proteins from ejaculated and epididymidal sperm was investigated. Result show that the glycosylation status is modified as spermatozoa migrate through the epididymis. Hyaluronidase activity evaluated in protein extracts from spermatozoa of the three different epididymal sections revealed that the activity is higher at pH 7 than 4 and is not affected by epididymal maturation. These data strongly suggest that p80 is the bovine PH‐20. Mol. Reprod. Dev. © 2005 Wiley‐Liss, Inc.
DkkL1 (Soggy), a Dickkopf family member, localizes to the acrosome during mammalian spermatogenesis
Authors: Kohn Matthew J. , Kaneko Kotaro J. , DePamphilis Melvin L. 
Published: May 2005

AbstractDickkopf‐like 1 (DkkL1) is related to the Dickkopf gene family, a group of proteins that are characterized as secreted antagonists of Wingless (Wnt) signal transduction proteins. DkkL1 mRNA is found in preimplantation mouse embryos and in developing neural tissue, but in adults it is found primarily in the testes. In an effort to elucidate its function, the distribution of DkkL1 protein in mouse testis and mature sperm was analyzed by immuno‐histochemistry and immuno‐blotting techniques. DkkL1 first appeared in the developing spermatocytes in seminiferous tubules as early as Stage XII, coincident with the appearance of DkkL1 mRNA. Surprisingly, however, DkkL1 localized to the developing acrosome in spermatocytes and spermatids and to the acrosome in mature sperm. Furthermore, DkkL1 was N‐glycosylated in the testis, but it did not appear to be excreted, and the DkkL1 in mature sperm was no longer N‐glycosylated, suggesting that additional post‐translational modifications occurred during the final stages of spermatogenesis. These results identify a member of the Dickkopf family as a novel acrosomal protein that may be involved in acrosome assembly or function, a unique role for a secreted signaling molecule. Mol. Reprod. Dev. Published 2005 Wiley‐Liss, Inc.
Greedy approximation algorithms for directed multicuts
Authors: Kortsarts Yana , Kortsarz Guy , Nutov Zeev 
Published: May 2005

AbstractThe Directed Multicut (DM) problem is: given a simple directed graph G = (V, E) with positive capacities ue on the edges, and a set K ⊆ V × V of ordered pairs of nodes of G, find a minimum capacity K‐multicut; C ⊆ E is a K‐multicut if in G − C there is no (s, t)‐path for any (s, t) ⫅ K. In the uncapacitated case (UDM) the goal is to find a minimum size K‐multicut. The best approximation ratio known for DM is
$O(\min\{\sqrt{n},opt\})$
by Gupta, where n = |V|, and opt is the optimal solution value. All known nontrivial approximation algorithms for the problem solve large linear programs. We give the first combinatorial approximation algorithms for the problem. Our main result is an Õ(n2/3/opt1/3)‐approximation algorithm for UDM, which improves the $O(\min\{opt,\sqrt{n}\})$‐approximation for opt = Ω(n1/2+ϵ). Combined with the article of Gupta, we get that UDM can be approximated within better than $O(\sqrt n)$, unless $opt={\tilde \Theta}(\sqrt n)$. We also give a simple and fast O(n2/3)‐approximation algorithm for DM. © 2005 Wiley Periodicals, Inc. NETWORKS, Vol. 45(4), 214–217 2005
Changes in isotretinoin prescribing before and after implementation of the System to Manage Accutane Related Teratogenicity™ (SMART™) risk management program
Authors: Mendelsohn Aaron B. , Governale Laura , Trontell Anne , Seligman Paul 
Published: May 2005

AbstractPurposeTo assess changes in isotretinoin prescribing following the implementation of the System to Manage Accutane Related Teratogenicity™ (SMART™) risk management program.MethodsUsing nationally representative commercial data resources on prescription drug dispensing patterns, surveys of office‐based physician practices, and a large, claims database from a pharmacy benefits manager (PBM), we examined the total number of isotretinoin prescriptions (new and refill), prescriber speciality, and patient characteristics (age, gender, severity of acne indication) in the year before (April 2001–March 2002) and the year following (April 2002–March 2003) implementation of the SMART™ program.ResultsIn the 12‐months prior to SMART™, 1 508 000 prescriptions were dispensed for isotretinoin, declining approximately 23% to 1 160 000 prescriptions in the year following SMART™. There was little or no change in prescriber specialty, severity of acne, and patient age and gender.ConclusionSMART™ may have lead to a decrease in isotretinoin prescriptions. Further research is needed to determine whether the reduced number of isotretinoin prescriptions reflects appropriate use or inhibited use resulting in loss of access to the product's benefits. Copyright © 2005 John Wiley & Sons, Ltd.
Extinction coefficient of polyolefin foams
Authors: Campo‐Arnáiz R. A. , Rodríguez‐Pérez M. A. , Calvo B. , de Saja J. A. 
Published: May 2005

AbstractThe extinction coefficient of a collection of polyolefin foams was investigated experimentally and theoretically. Transmittance spectra were measured with Fourier transform infrared spectroscopy (FTIR) for samples of various thicknesses and different chemical compositions, densities, colors and structural characteristics. The extinction coefficients were then calculated by applying Beer's law. The results showed that the extinction coefficient decreased with the mean cell size and that this was the main structural parameter influencing the extinction coefficient of the foams under study. The experimental results agreed well with the Glicksman model. Moreover, the total thermal conductivity was calculated in terms of the Rosseland equation with an accuracy of 5%. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1608–1617, 2005
Polymer characterization by interaction chromatography
Authors: Chang Taihyun 
Published: May 2005

AbstractLiquid chromatography (LC) is a powerful tool for the characterization of synthetic polymers, that are inherently heterogeneous in molecular weight, chain architecture, chemical composition, and microstructure. Of different versions of the LC methods, size exclusion chromatography (SEC) is most commonly used for the molecular weight distribution analysis. SEC separates the polymer molecules according to the size of a polymer chain, a well‐defined function of molecular weight for linear homopolymers. The same, however, cannot be said of nonlinear polymers or copolymers. Hence, SEC is ill suited for and inefficient in separating the molecules in terms of chemical heterogeneity, such as differences in chemical composition of copolymers, tacticity, and functionality. For these purposes, another chromatographic method called interaction chromatography (IC) is found as a better tool because its separation mechanism is sensitive to the chemical nature of the molecules. The IC separation utilizes the enthalpic interactions to vary adsorption or partition of solute molecules to the stationary phase. Thus, it is used to separate polymers in terms of their chemical composition distribution or functionality. Further, the IC method has been shown to give rise to much higher resolution over SEC in separating polymers by molecular weight. We present here our recent progress in polymer characterization with this method. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1591‐1607, 2005
Crystallization analysis fractionation
Authors: Soares João B. P. , Anantawaraskul Siripon 
Published: May 2005

AbstractCrystallization analysis fractionation (CRYSTAF) is an analytical technique for determining the distribution of chain crystallizabilities of semicrystalline polymers. After only approximately a decade since it was developed, CRYSTAF has become one of the most important characterization techniques in polyolefin characterization laboratories because it provides fast and crucial information required for the proper understanding of polymerization mechanisms and structure–property relationships. In the polyolefin industry, it has been established as an indispensable tool for product development and product quality monitoring. This highlight article covers basic operation procedures, applications, and theoretical aspects of polymer fractionation with CRYSTAF. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1557–1570, 2005
Confinement effects on the structure and dynamics of polymer systems from the mesoscale to the nanoscale
Authors: Barnes M. D. , Mehta A. , Kumar P. , Sumpter B. G. , Noid D. W. 
Published: May 2005

AbstractIn this article, we review some of our recent progress in experimental and simulation methods for generating, characterizing, and modeling polymer microparticles and nanoparticles in a number of polymer and polymer‐blend systems. By using instrumentation developed for probing single fluorescent molecules in micrometer‐sized liquid droplets, we have shown that polymer particles of nearly arbitrary size and composition can be made with a size dispersion that is ultimately limited by the chain length and number distribution within the droplets. Depending on the timescale for solvent evaporation—a tunable parameter in our experiments—the phase separation of otherwise immiscible polymers can be avoided by confinement effects, and homogeneous polymer‐blend microparticles or nanoparticles can be produced. These particles have tunable properties that can be controlled by the simple adjustment of the size of the particle or the relative mass fractions of the polymer components in solution. Physical, optical, and mechanical properties of a variety of microparticles and nanoparticles, differing in size and composition, have been examined with extensive classical molecular dynamics calculations in conjunction with experiments to gain deeper insights into the fundamental nature of their structure, dynamics, and properties. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 1571‐1590, 2005