bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of rigid particle size on the toughness of filled polypropylene
Authors: Dubnikova I. L. , Berezina S. M. , Antonov A. V. 
Published: October 2004

AbstractThe role of rigid particle size in the deformation and fracture behavior of filled semicrystalline polymer was investigated with systems based on polypropylene (PP) and model rigid fillers [glass beads, Al(OH)3]. The regularities of the influence of particle content and size on the microdeformation mechanisms and fracture toughness of the composites at low and high loading rates were found. The existence of the optimal particle size for fixed filler content promoting both maximum ultimate elongation of the composite at the tensile and maximum toughness at impact test was shown. The decrease of the toughening effect with both decreasing and increasing particle size regarding the optimal one was explained by dual role of particle size, correspondingly as either “adhesive” or “geometric” factors of fracture. The adhesive factor is due by the increase of debonding stress with the particle size decrease and the voiding difficulty resulting in the restriction of plastic flow. The geometric factor consists in the dramatic decrease of the composite strength at break if the void size exceeds the critical size of defect (for a given matrix) at which the crack initiation occurs. The analysis of the filled polymer toughness dependencies upon the particle size revealed that a capacity of rigid particles for the energy dissipation at the high loading rate depends on two factors: (i) ability of the dispersed particles to detach from matrix and to initiate the matrix local shear yielding at the vicinity of the voids and (ii) the size of the voids forming. Based on the findings it was concluded that the optimal minimal rigid particle size for the polymer toughening should answer the two main requirements: (i) to be smaller than the size of defect dangerous for polymer fracture and (ii) to have low debonding stress (essentially lower compared to the polymer matrix yield stress). © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1917–1926, 2004
Thermomechanical film properties and aging of blends of poly(lactic acid) and malonate oligomers
Authors: Ljungberg N. , Wesslén B. 
Published: October 2004

AbstractMalonate oligomers were synthesized as plasticizers for poly(lactic acid) (PLA). Esterification reactions were performed between diethyl bishydroxymethyl malonate (DBM) and either adipoyl dichloride or succinyl dichloride. Two molar masses were obtained within each series. Blending was carried out with PLA and the four oligomers as well as the monomeric unit from the syntheses (DBM). Dynamic mechanical analysis and differential scanning calorimetry were used to investigate the viscoelastic mechanical and thermal film properties of the blends. All the investigated plasticizers reduced the glass‐transition temperature of PLA, and the plasticization effect was better for the plasticizers of low molar mass. However, the amorphous domains of PLA became saturated with plasticizer at a certain concentration, and phase separation occurred. A higher molar mass of the plasticizer caused this saturation to occur at lower plasticizer concentrations. Subsequently, the aging of the blends at the ambient temperature for 4 months induced phase separation in the blends containing DBM, whereas those with an oligomeric plasticizer were stable and remained compatible with PLA within the aging period. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2140–2149, 2004
Antimicrobial and physical properties of woolen fabrics cured with citric acid and chitosan
Authors: Hsieh S.‐H. , Huang Z. K. , Huang Z. Z. , Tseng Z. S. 
Published: October 2004

AbstractIn this study, we used citric acid (CA) as a crosslinking agent, mixed with biopolymer molecular chitosan, to perform a pad–dry–cure treatment on woolen fabrics to study its antimicrobial effects and physical properties with the help of IR spectroscopy, electron microscopy, and differential thermal analysis. From the experimental results, we learned that CA did not crosslink with the woolen fibers if the woolen fabrics were not oxidized by potassium permanganate and that after oxidization, CA produced esterification with the OH group of the wool and chitosan and transamidation with theNH2 group of the wool to form a crosslink. The surface crosslinks of the oxidized woolen fibers were relatively coarse, which is undesirable for shrink‐proofing and yet beneficial for the antimicrobial and antiseptic effects of the woolen fabrics. It had a negative effect on the fabric softness, yellowness, stretching resistance, and elongation percentage. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1999–2007, 2004
A one‐step method for fabricating chitosan microspheres
Authors: Kuo Shyh Ming , Niu Gregory Cheng‐Chie , Chang Shwu Jen , Kuo Chia Hung , Bair Miin Shyan 
Published: October 2004

AbstractA simple and in situ method, by using a high‐voltage electrostatic system, for the fabrication of chitosan microspheres (in a form of isolatable microgels) by an extrusion process, exhibiting variable sizes and different membrane structures, was presented. The chitosan microspheres exhibited good sphericity and were in the range of 185.8 ± 13.8 to 380.9 ± 11.5 μm in diameter. There were two significant factors, the pump flow rate and electrostatic field strength, that affected the chitosan microsphere size. The microsphere size decreased when the flow rate was increased from 0.1 to 0.4 mL/h. Also, the microsphere size decreased when the electrostatic field strength was increased from 5.5 to 6.5 kV/cm. However, when the electrostatic field strength was raised to 7 kV/cm and higher, the microsphere size increased. For the latter case, with other parameters fixed, chitosan microsphere size can be controlled by adjusting the electrostatic field strength and predetermined by a simple linear regression equation: Microsphere Diameter (D, in μm) = −(75.48) + 45.67 × (Electrostatic Field Strength, E, in kV/cm), at [7 ≤ (Electrostatic Field Strength) ≤ 10] (R2 = 0.956, P < 0.001). Following treatment with various ratios of crosslinking/gelating (Na5P3O10/NaOH) agents, the prepared chitosan microspheres exhibited distinct membrane structures that yielded various mechanical strengths. In the Na5P3O10/NaOH ratio of 19, the chitosan microspheres had a distinct two‐layer structure. The selection of crosslinking/gelating ratio provided an additional degree of freedom, permitting the simultaneous regulation of mechanical properties and permeability of the microspheres, without extra manipulation, and thus, improved applicability in the biomedical field. When the chitosan microsphere extrusion process was used to encapsulate β‐tricalcium phosphate powder for application as bony material, we found that the ultra fine β‐tricalcium phosphate powder was trapped inside of the membrane very well. After appropriate collecting procedures, stored microspheres also retained good spherical shape. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2150–2157, 2004
Multifunctional coupling agents. II. Chain extension and terminal group modification of polyamides
Authors: Jakisch L. , Komber H. , Wursche R. , Böhme F. 
Published: October 2004

AbstractNew bifunctional coupling agents possessing one 2‐oxazoline group and one 2‐oxazinone group were converted in a Haake melt mixer or extruder with PA6 and PA12. It was shown by means of NMR spectroscopic investigations that the 2‐oxazoline group reacted mainly with carboxylic groups whereas the oxazinone group reacted preferably with the amino groups. Both reactions proceeded with high selectivity and independent from each other. In the case of carboxy/amino group terminated polyamides, the conversions resulted in increased molecular weights since both reactive terminal groups of the polyamides were addressed simultaneously by the coupling agent. In the case of amino group terminated polyamides, the conversion with the bifunctional coupling agent resulted in oxazoline terminated polymer chains. Unlike PA6, it was possible to convert PA12 in two steps. At lower temperatures (210°C) and short reaction times (2 min), the reaction of the oxazinone group with the amino groups was predominant, whereas the reaction of the oxazoline group with the carboxylic groups proceeded to a sufficient extent only after longer reaction times or at higher temperatures. In the case of PA6, processing temperatures of about 250°C were necessary. Here, a side reaction was observed that resulted in the formation of cyclic quinoxaline structures under evolution of water. This side reaction did not disturb the chain extension significantly. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2170–2177, 2004
Effect of CsBr–MnCl2 mixed fillers on the crystal structure and optical and electrical properties of poly(vinyl alcohol)
Authors: Abdelaziz M. 
Published: October 2004

AbstractPoly(vinyl alcohol) (PVA) films filled with (x)CsBr(15 − x)MnCl2, where 0.0 ≤ x ≤ 15%, were prepared by a casting technique. The crystal structure properties of the prepared films were examined by XRD, DTA, and FTIR. A correlation between XRD, DTA, and FTIR of the filled polymer was discussed. Optical absorption measurements revealed two optical band gaps (Eg1 and Eg2). The electrical properties were studied using dc electrical conductivity. The filling level (FL) dependency of Eg1 and Eg2, thermal activation energy (ΔE), and hopping distance (R0) are given to illustrate the behavior of the filled polymers. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2178–2186, 2004
The effect of fever, febrile illnesses, and heat exposures on the risk of neural tube defects in a Texas‐Mexico border population
Authors: Suarez Lucina , Felkner Marilyn , Hendricks Kate 
Published: October 2004

AbstractBACKGROUNDHyperthermia produces neural tube defects (NTDs) in a variety of animal species. Elevated maternal body temperatures may also place the developing human embryo at risk. We examined the relation between maternal hyperthermia and the development of NTDs in a high‐risk Mexican‐American population.METHODSCase‐women were Mexican‐American women with NTD‐affected pregnancies who resided and delivered in any of the 14 Texas counties bordering Mexico, during 1995–2000. Control‐women were randomly selected from study area residents delivering normal live births, frequency‐matched to cases by hospital and year. Information on maternal fevers, febrile illnesses, exposures to heat generated from external sources, and hyperthermia‐inducing activities was gathered through in‐person interviews, conducted about six weeks postpartum.RESULTSThe risk effect (OR) associated with maternal fever in the first trimester, compared to no fever, was 2.9 (95% CI, 1.5–5.7). Women taking fever‐reducing medications showed a lower risk effect (OR, 2.4; 95% CI, 1.0–5.6) than those who did not (OR, 3.8; 95% CI, 1.4–10.9). First‐trimester maternal exposures to heat devices such as hot tubs, saunas, or electric blankets were associated with an OR of 3.6 (95% CI, 1.1–15.9). Small insignificant effects were observed for activities such as cooking in a hot kitchen (OR, 1.6; 95% CI, 1.0–2.6) and working or exercising in the sun (OR, 1.4; 95% CI, 0.9–2.2).CONCLUSIONSMaternal hyperthermia increases the risk for NTD‐affected offspring. Women intending to become pregnant should avoid intense heat exposures, carefully monitor and manage their febrile illnesses, and routinely consume folic acid supplements. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Design, synthesis, and evaluation of peptides with estrogen‐like activity
Authors: Kasher Roni , Gayer Batya , Kulik Tikva , Somjen Dalia , Venkatesh Natarajan , Fridkin Mati , Katchalski‐Katzir Ephraim , Kohen Fortune 
Published: October 2004

AbstractCurrently used antiestrogenic drugs against hormone‐dependent breast cancer, and estrogenic drugs used in treatment of osteoporosis, are associated with risk factors. Therefore, there is a strong need to develop selective estrogen receptor modulators with better tissue selectivity. In a recent study (Peptides, 2002, Vol. 3, 573–580), we used a monoclonal antibody to estradiol (mAb‐E2) to screen a phage‐display peptide library. We identified a 15‐mer peptide (peptide H5) that recognizes mAb‐E2 (IC50 1 μM) and estrogen receptor (ER)α (IC50 500 μM) but not ERβ, and displays estrogen‐like activity in vitro and in vivo. In this study, we designed and prepared peptides based on peptide H5, which possess improved estrogenic activity, by evaluating their binding to mAb‐E2 and to ERs. Initially, we determined the minimal binding sequence of peptide H5 capable of binding mAb‐E2 and ER. Subsequently, systematic single‐residue replacements of the minimal sequence, followed by multiple‐residue replacements, yielded hexa‐ and heptapeptides with increased affinities to mAb‐E2 and to ER. The most promising peptides, VSWFFE (EMP‐1) and VSWFFED (EMP‐2) (EMP: estrogen‐mimetic peptide), bind mAb‐E2 with high affinity (IC50 of 6 and 30 nM, respectively), recognize ERs with increased affinity (IC50 of 100 μM for ERα, and 100–250 μM for ERβ), and possess estrogenic activity in vivo. The short peptides described in this study may be used as potential lead compounds for developing new ER ligands. © 2004 Wiley Periodicals, Inc. Biopolymers (Pept Sci), 2004
Das Bioisosterie‐Konzept: Arzneistoffentwicklung
Authors: Siebert Carsten D. 
Published: October 2004

AbstractBioisosterie bedeutet gleiche räumliche Ausdehnung
bei vergleichbarer Wirkung in biologischen Systemen. Dies bezieht sich auf
pharmakologisch wirksame Verbindungen, die vor allem in vivo einen
vergleichbaren Effekt erzielen. Die Paare Benzol‐Thiophen, Benzol‐Pyridin und
Thiophen‐Furan sind bekannte Beispiele für Bioisosterie in der
Wirkstoffforschung.
Clemens Winkler – zum 100. Todestag
Authors: Volke Klaus 
Published: October 2004

AbstractClemens Winklers geniale analytische Fähigkeiten führten 1886 zur Entdeckung des Elementes Germanium. Damit konnte eine Lücke im Periodensystem der Elemente von Dmitrij Mendelejew (1834 – 1907) und Lothar Meyer (1830 – 1895) geschlossen werden.
Phasenumwandlung birgt Erinnerung
Authors: Feil Sylvia 
Published: October 2004

AbstractManche Stoffe scheinen ein Erinnerungsvermögen zu besitzen: Sie kehren unter Verrichtung mechanischer Arbeit in eine vorher eingeprägte Form zurück. Eine Legierung aus Nickel und Titan in nahezu stöchiometrischem Verhältnis – Nitinol – verfügt über ein solches Formgedächtnis. Dahinter steckt eine Festphasenumwandlung.
Museen und “Science Center” im Netz – reloaded
Authors: Hildebrandt Henry 
Published: October 2004

AbstractScience Center sind “in” – Museen sind “out”. Allerdings: Wo eigentlich ist der Unterschied? Vielleicht sprechen neue Begriffe auch neue Zielgruppen an. Denn auch alte Museen haben schon immer mit ihren Ausstellungen zum aktiven Umgang aufgefordert – also: Alles nur geklaut?
Digital image interpolation with warping of coordinate point and biasing of signal amplitude
Authors: Shimura Atsushi , Taguchi Akira 
Published: October 2004

AbstractSince the dimensions for digital images are set by the acquisition system, digital image enlargement is indispensable when the dimensions that can be displayed are larger in the display system than in the acquisition system. Conventionally, this enlargement process was performed by interpolation. The digital image enlargement corresponds to a larger Nyquist frequency, but the frequency band that is expanded during the enlargement cannot be considered by the interpolation scheme, and blur is produced in the enlarged image. The parts where the image blur stands out subjectively are primarily the signals forming the image contours having the step edge shape and the details of the image consisting of mountain‐ and valley‐shaped signals when viewed microscopically. Therefore, the proposed method moves the coordinate points interpolated to preserve the discontinuities of step edge signals and decides whether the interpolated points are the vertices of the mountain‐ or valley‐shaped signals, and then moves the amplitudes of the interpolated points for creating these peak signals up or down. In other words, we explain an interpolation scheme involving the warping and biasing that randomly moves the coordinate points and the signal amplitudes, and implement digital image interpolation with improved resolution. Furthermore, the parameter settings for the proposed method are both objectively and subjectively evaluated. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(2): 10–21, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20095
Reorganizing learning resources on the WWW and its application to adaptive recommendation for navigational support
Authors: Hasegawa Shinobu , Kashihara Akihiro , Toyoda Jun'ichi 
Published: October 2004

AbstractAs the Internet rapidly increases in popularity, learning resources on the WWW are being used more and more. Since there are many learning resources that describe the same topic from different perspectives on the WWW, it is possible to deepen understanding of topics by making good use of them. Though there exists a tremendous amount of learning resources, in many cases they do not have clear descriptions of their properties, such as “What you can learn and how.” Thus, it is very difficult for learners to select learning resources that match their objectives. As an approach to this issue, we propose a method of providing indexes for description of the properties of learning resources, and of reorganizing learning resources based on them. In order to show the usefulness of this reorganization, we have developed a resource navigation support method that recommends learning resources at each step, with the aim of helping learners to deepen their understanding of a certain subject of study step by step. Testing and evaluation have shown the validity of this navigation support method based on resource indexes. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 88(2): 52–63, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20158
Equal emissions per capita over time – a proposal to combine responsibility and equity of rights for post‐2012 GHG emission entitlement allocation
Authors: Bode Sven 
Published: October 2004

AbstractAny effective future climate policy regime based on the Kyoto Protocol requires the determination of the concrete contribution regarding time and quantity for each party. Based on the two justice principles, responsibility and equity of rights, that form the basis for the so‐called Brazilian Proposal and Contraction and Convergence respectively, a new approach is developed: future emission rights are allocated on the basis of equal emissions per capita over time. By so doing not only are emissions per capita (EPC) taken into account during the allocation but also their evolution over time. This may result in negative quantities of emission rights for some parties due to their historical ‘burden’. On the other hand, parties with low EPC would be allocated large amounts of ‘fair air’. Even though this approach may currently lack political support by powerful parties, it offers another analytical reference point for the political bargaining process on future allocations. Copyright © 2004 John Wiley & Sons, Ltd and ERP Environment.
Expression of the SH2D1A gene is regulated by a combination of transcriptional and post‐transcriptional mechanisms
Authors: Okamoto Susumu , Ji Hongbin , Howie Duncan , Clarke Kareem , Gullo Charles , Manning Stephen , Coyle Anthony J. , Terhorst Cox 
Published: October 2004

AbstractThe SH2D1A gene, which is altered or deleted in patients with X‐linked lymphoproliferative disease, encodes the small protein SAP (for SLAM‐associated protein) that is expressed in T and NK cells. A 22‐bp fragment in close proximity to an initiator‐like site was defined as the basal promoter of mouse SH2D1A, and a highly homologous 33‐bp segment was defined as the human basal promoter. When an Ets consensus site was mutated, no reporter activity was detectable. Gel mobility supershift assays revealed that the two transcription factors Ets‐1 and Ets‐2 bind to the human and mouse sequences. The involvement of Ets‐1 and Ets‐2 in expression of SH2D1A was functionally confirmed by overexpression studies of their dominant‐negative forms. We also found that SH2D1A mRNA decays very rapidly in mouse T cells, and its 3′ untranslated region (UTR) has RNA‐destabilizing activity in transfection studies with reporter/3′ UTR constructs. As judged by RNA‐gel mobility shift assays, this rapid degradation of SH2D1A mRNA was due to a balance in binding of the factors AUF1 and HuR to its 3′ UTR. Although the SH2D1A mRNA level decreased upon triggering of the T cell receptor (TCR), the RNA degradation rate itself was not altered by TCR engagement.
The imbalance between Bim and Mcl‐1 expression controls the survival of human myeloma cells
Authors: Gomez‐Bougie Patricia , Bataille Régis , Amiot Martine 
Published: October 2004

AbstractMultiple myeloma is a fatal B cell malignancy characterized by the accumulation of plasma cells within the bone marrow. IL‐6 is a major survival factor for myeloma cells. Bcl‐2 protein family regulates pathways to apoptosis that are activated upon growth factor deprivation. Pro‐apoptotic proteins that have only a single Bcl‐2 homology domain, BH3‐only, are potent inducers of apoptosis. In myeloma cells, Mcl‐1 has been shown to be a major anti‐apoptotic protein that appears to regulate cell survival through the JAK/STAT pathway. In this study, we examined the regulation of the BH3‐only protein Bim and its interaction with Mcl‐1. The three major Bim isoforms are expressed in myeloma cells and are negatively regulated by IL‐6. Blockade of IL‐6 signaling induces an up‐regulation of Bim concomitant to Mcl‐1 down‐regulation. Of major interest, Bim is found strongly associated with Mcl‐1 in viable myeloma cells while this interaction is disrupted under apoptosis induction. Of note, while Bim is also found strongly associated to Bcl‐2, this interaction is not changed under apoptosis induction. Thus, in myeloma cells, Mcl‐1 neutralizes Bim through complex formation and therefore prevents apoptosis. Under apoptosis induction, the disappearance of Mcl‐1 allows Bim to exercise its pro‐apoptotic function and to activate Bax.
Distinct roles of CTLA‐4 and TGF‐β in CD4+CD25+ regulatory T cell function
Authors: Tang Qizhi , Boden Elisa K. , Henriksen Kammi J. , Bour‐Jordan Helene , Bi Mingying , Bluestone Jeffrey A. 
Published: October 2004

AbstractBoth CTLA‐4 and TGF‐β have been implicated in suppression by CD4+CD25+ regulatory T cells (Treg). In this study, the relationship between CTLA‐4 and TGF‐β in Treg function was examined. Blocking CTLA‐4 on wild‐type Treg abrogated their suppressive activity in vitro, whereas neutralizing TGF‐β had no effect, supporting a TGF‐β‐independent role for CTLA‐4 in Treg‐mediated suppression in vitro. In CTLA‐4‐deficient mice, Treg development and homeostasis was normal. Moreover, Treg from CTLA‐4‐deficient mice exhibited uncompromised suppressive activity in vitro. These CTLA‐4‐deficient Treg expressed increased levels of the suppressive cytokines IL‐10 and TGF‐β, and in vitro suppression mediated by CTLA‐4–/– Treg was markedly reduced by neutralizing TGF‐β, suggesting that CTLA‐4‐deficient Treg develop a compensatory suppressive mechanism through CTLA‐4‐independent production of TGF‐β. Together, these data suggest that CTLA‐4 regulates Treg function by two distinct mechanisms, one during functional development of Treg and the other during the effector phase, when the CTLA‐4 signaling pathway is required for suppression. These results help explain contradictions in the literature and support the existence of functionally distinct Treg.