bluuebunny/crossref_metadata_2025 huggingface dataset:
Algorithm for identifying and separating beats from arterial pulse records
Authors: Treo Ernesto F , Herrera Myriam C , Valentinuzzi Max E
Published: August 2005

Background

This project was designed as an epidemiological aid-selecting tool for a small country health center with the general objective of screening out possible coronary patients. Peripheral artery function can be non-invasively evaluated by impedance plethysmography. Changes in these vessels appear as good predictors of future coronary behavior. Impedance plethysmography detects volume variations after simple occlusive maneuvers that may show indicative modifications in arterial/venous responses. Averaging of a series of pulses is needed and this, in turn, requires proper determination of the beginning and end of each beat. Thus, the objective here is to describe an algorithm to identify and separate out beats from a plethysmographic record. A secondary objective was to compare the output given by human operators against the algorithm.

Methods

The identification algorithm detected the beat's onset and end on the basis of the maximum rising phase, the choice of possible ventricular systolic starting points considering cardiac frequency, and the adjustment of some tolerance values to optimize the behavior. Out of 800 patients in the study, 40 occlusive records (supradiastolic- subsystolic) were randomly selected without any preliminary diagnosis. Radial impedance plethysmographic pulse and standard ECG were recorded digitizing and storing the data. Cardiac frequency was estimated with the Power Density Function and, thereafter, the signal was derived twice, followed by binarization of the first derivative and rectification of the second derivative. The product of the two latter results led to a weighing signal from which the cycles' onsets and ends were established. Weighed and frequency filters are needed along with the pre-establishment of their respective tolerances. Out of the 40 records, 30 seconds strands were randomly chosen to be analyzed by the algorithm and by two operators. Sensitivity and accuracy were calculated by means of the true/false and positive/negative criteria. Synchronization ability was measured through the coefficient of variation and the median value of correlation for each patient. These parameters were assessed by means of Friedman's ANOVA and Kendall Concordance test.

Results

Sensitivity was 97% and 91% for the two operators, respectively, while accuracy was cero for both of them. The synchronism variability analysis was significant (p < 0.01) for the two statistics, showing that the algorithm produced the best result.

Conclusion

The proposed algorithm showed good performance as expressed by its high sensitivity. The correlation analysis demonstrated that, from the synchronism point of view, the algorithm performed the best detection. Patients with marked arrhythmic processes are not good candidates for this kind of analysis. At most, they would be singled out by the algorithm and, thereafter, to be checked by an operator.
Characterization of a Novel Rat Epididymal Cell Line to Study Epididymal Function
Authors: Dufresne Julie , St-Pierre Nancy , Viger Robert S. , Hermo Louis , Cyr Daniel G.
Published: August 2005

The epididymis is an androgen-dependent organ that allows spermatozoa to become fully functional as they pass through this tissue. The specialized functions of the epididymis are mediated by interactions between epididymal epithelial cells and between epididymal cells and spermatozoa. Although the critical role of the epididymis in sperm maturation is well established, the mechanisms regulating cell-cell interactions remain poorly understood because of the lack of appropriate cell line models. We now report the characterization of a novel rat caput epididymal cell line (RCE) that was immortalized by transfecting primary cultures of rat epididymal cells with the simian virus 40 large T antigen. At the electron microscope level, the cell line was composed of epithelial principal cells with characteristics of in vivo cells; principal cells had well-developed Golgi apparatus, abundant endoplasmic reticulum cisternae, and few endosomes. RCE cells expressed the mRNAs coding for the androgen receptor, estrogen receptor α, and 4-ene-steroid-5-α-reductase types 1 and 2 as well as epididymal-specific markers Crisp-1 and epididymal retinoic acid binding protein. Epididymal retinoic acid binding protein expression was significantly induced with dihydrotestosterone, although this effect was not blocked by flutamide, suggesting that RCE cells are not androgen responsive. Neighboring cells formed tight and gap junctions characteristic of epididymal cells in vivo and expressed tight (occludin and claudin-1, -3, and -4) and gap junctional proteins (connexin-26, -30.3, -32, and -43). The RCE cell line displays many characteristics of epithelial principal cells, thus providing a model for studying epididymal cell functions.
Estrogens Up-Regulate the Fas/FasL Apoptotic Pathway in Lactotropes
Authors: Jaita G. , Candolfi M. , Zaldivar V. , Zárate S. , Ferrari L. , Pisera D. , Castro M. G. , Seilicovich A.
Published: August 2005

The Fas/FasL system provides the major apoptotic mechanism for many cell types, participating in cell turnover in hormone-dependent tissues. In the present study, we localized both Fas and FasL in anterior pituitary cells, mainly in lactotropes and somatotropes. The percentage of anterior pituitary cells showing immunoreactivity for Fas or FasL was higher in cells from rats killed in proestrus than in diestrus. Also, the proportion of pituitary cells from ovariectomized (OVX) rats expressing Fas or FasL increased in the presence of 17β-estradiol (10−9m). This steroid increased the percentage of lactotropes with immunoreactivity for Fas or FasL and the percentage of somatotropes expressing Fas. Activation of Fas by an agonist anti-Fas antibody (Mab-Fas) decreased the vi-ability—3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT assay)—of anterior pituitary cells from OVX rats cultured in the presence of 17β-estradiol. Also, membrane-bound FasL decreased cell viability—[3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] assay (MTS assay)—only when anterior pituitary cells from OVX rats were incubated with 17β-estradiol. Moreover, FasL increased the percentage of hypodiploid anterior pituitary cells (flow cytometry). Mab-Fas increased the percentage of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL)-positive pituitary cells and lactotropes from OVX rats only when cells were incubated in the presence of 17β-estradiol. Also, Mab-Fas triggered apoptosis of anterior pituitary cells from rats killed at proestrus but not at diestrus. Our results show that 17β-estradiol up-regulates the expression of the Fas/FasL system in anterior pituitary cells and increases Fas-induced apoptosis in lactotropes, suggesting that Fas-induced apoptosis could be involved in the pituitary cell renewal during the estrous cycle.
Insulin at Physiological Concentrations Selectively Activates Insulin But Not Insulin-Like Growth Factor I (IGF-I) or Insulin/IGF-I Hybrid Receptors in Endothelial Cells
Authors: Li Guolian , Barrett Eugene J. , Wang Hong , Chai Weidong , Liu Zhenqi
Published: August 2005

In muscle, physiologic hyperinsulinemia, presumably acting on endothelial cells (ECs), dilates arterioles and regulates both total blood flow and capillary recruitment, which in turn influences glucose disposal. In cultured ECs, however, supraphysiological (e.g. ≥10 nm) insulin concentrations are typically used to study insulin receptor (IR) signaling pathways and nitric oxide generation. IGF-I receptors (IGF-IRs) are more abundant than IR in ECs, and they also respond to high concentrations of insulin. To address whether IR mediates responses to physiologic insulin stimuli, we examined the insulin concentration dependence of IR and IGF-IR-mediated insulin signaling in bovine aortic ECs (bAECs). We also assessed whether insulin/IGF-I hybrid receptors were present in bAECs. Insulin, at 100–500 pm, significantly stimulated the phosphorylation of IRβ, Akt1, endothelial isoform of nitric oxide synthase, and ERK 1/2 but not the IGF-IRβ subunit. At concentrations 1–5 nm or greater, insulin dose-dependently enhanced the tyrosine phosphorylation of IGF-IRβ, and this was inhibited by IGF-IR neutralizing antibody. In addition, immunoprecipitation of IRβ pulled down the IGF-IRβ, and the IRβ immunocytochemically colocalized with IGF-IRβ, suggesting that ECs have insulin/IGF-I hybrid receptors. We conclude that: 1) insulin at physiological concentrations selectively activates IR signaling in bAECs; 2) bAECs express IGF-IR and insulin/IGF-I hybrid receptors in addition to IR; 3) high concentrations of insulin (≥1–5 nm) activate IGF-IR and hybrid receptors as well as IR; and 4) this crossover activation can confound interpretation of studies of insulin action in ECs when high insulin concentrations are used.
Proteasomal Proteolysis in the Adrenergic Induction of Arylalkylamine-N-Acetyltransferase in Rat Pinealocytes
Authors: Terriff David L. , Chik Constance L. , Price Donald M. , Ho Anthony K.
Published: August 2005

In this study, we investigated the effect of proteasomal inhibition on the induction of arylalkylamine-N-acetyltransferase (AA-NAT) enzyme in cultured rat pinealocytes, using two proteasome inhibitors, MG132 and clastolactacystin β-lactone (c-lact). Addition of c-lact or MG132 3 h after norepinephrine (NE) stimulation produced a significant increase in AA-NAT protein level and enzyme activity. However, when the proteasome inhibitors were added before or together with NE, significant reductions of the NE-induced aa-nat mRNA, protein, and enzyme activity were observed. A similar inhibitory effect of MG132 on aa-nat transcription was observed when cells were stimulated by dibutyryl cAMP, indicating an effect distal to a post-cAMP step. The inhibitory effect of MG132 on adrenergic-induced aa-nat transcription was long lasting because it remained effective after 14 h of washout and appeared specific for aa-nat because the induction of another adrenergic-regulated gene, MAPK phosphatase-1, by NE was not affected. Time-profile studies revealed that the inhibitory effect of MG132 on NE-stimulated aa-nat induction was detected after 1 h, suggesting accumulation of a protein repressor as a possible mechanism of action. This possibility was also supported by the finding that the inhibitory effect of c-lact on NE-induced aa-nat induction was markedly reduced by cycloheximide, a protein synthesis inhibitor. Together, these results support an important role of proteasomal proteolysis in the adrenergic-mediated induction of aa-nat transcription through its effect on a protein repressor.
Changes in Expression of Hypothalamic Releasing Hormone Receptors in Individual Rat Anterior Pituitary Cells during Maturation, Puberty and Senescence
Authors: Senovilla Laura , García-Sancho Javier , Villalobos Carlos
Published: August 2005

Anterior pituitary (AP) is formed by five different cell types, each one producing a different AP hormone whose secretion is regulated by a specific hypothalamic-releasing hormone (HRH). On the other hand, a significant number of AP cells express multiple HRH receptors (multiresponsive cells). Plastic changes in expression of HRH receptors in individual AP cells are involved in critical endocrine events. Here we have characterized the changes in functional responses to CRH, LHRH, TRH, and GHRH in individual AP cells throughout the whole life span of the rat. To this end, calcium responses to the HRHs were followed by single-cell imaging in freshly dispersed AP cells prepared from rats of different ages (0–540 postnatal days). Three different cell pools were identified: 1) monoresponsive cells, holding a single class of HRH receptor; 2) multiresponsive cells; and 3) nonresponsive cells. The relative abundance of each pool changed with age. Nonresponsive cells were abundant at birth, multiresponsive cells were abundant at puberty, and monoresponsive cells dominated at senescence. The relative abundance of each HRH receptor changed largely with age but not gender. In addition, the contribution of monoresponsive and multiresponsive cells to responses to each HRH changed very much with age. Thus, the anterior pituitary shows large changes in cell populations typed by functional responses to HRHs during maturation, puberty, and senescence.
Intrinsic and extrinsic regulators of developmental timing: from miRNAs to nutritional cues
Authors: Rougvie Ann E.
Published: August 2005

A fundamental challenge in biology is to understand the reproducibility of developmental programs between individuals of the same metazoan species. This developmental precision reflects the meticulous integration of temporal control mechanisms with those that specify other aspects of pattern formation,such as spatial and sexual information. The cues that guide these developmental events are largely intrinsic to the organism but can also include extrinsic inputs, such as nutrition or temperature. This review discusses the well-characterized developmental timing mechanism that patterns the C. elegans epidermis. Components of this pathway are conserved,and their links to developmental time control in other species are considered,including the temporal patterning of the fly nervous system. Particular attention is given to the roles of miRNAs in developmental timing and to the emerging mechanisms that link developmental programs to nutritional cues.
Sequence learning by action, observation and action observation
Authors: Bird Geoffrey , Osman Magda , Saggerson Anna , Heyes Cecilia
Published: August 2005

The serial reaction time (SRT) task was used to compare learning of a complex sequence by action (participants responded to sequential stimuli), by observation (participants watched but did not respond to sequential stimuli), and by action‐observation (participants watched an expert model responding to sequential stimuli). Each of these groups was compared with an untrained control group. Experiment 1 indicated that both observation and action‐observation were sufficient to support learning of a 12‐item second‐order conditional (SOC) sequence. Experiment 2 confirmed these findings, and showed that, as indexed by reaction time (RT), the extent of learning by observation and by action‐observation was comparable to that of action‐based learning. Using a recognition test, Experiment 2 and 3 also provided evidence that, whereas learning by stimulus observation was explicit, learning by action‐observation was implicit. These findings are consistent with a connection between motor systems and implicit learning, but do not support the hypothesis that overt action is necessary for implicit learning.
Modality effects in compounding with English inflectional morphology
Authors: Hayes Jennifer A. , Smith Pamela M. , Murphy Victoria A.
Published: August 2005

The treatment of plural morphemes in English noun–noun compounds is significant because it provides a test case for competing theories of language acquisition and representation. Even when the first noun in a compound refers to plural items, native speakers frequently use the singular form (Murphy, 2000). Sometimes, they will use the irregular plural form (‘mice chaser’) but very rarely are regular plurals (‘rats chaser’) used as the first noun in a compound. This effect has been found with native English‐ speaking children (Gordon, 1985; Nicoladis, 2000; Oetting & Rice, 1993; van der Lely & Christian, 2000); native English‐speaking teenagers (van der Lely & Christian, 2000); and native English‐speaking adults (Lardiere & Schwartz, 1997; Murphy, 2000). The apparent dissociation between regular and irregular plurals (i.e. that irregular plurals are included before a second noun but regular plurals are almost never included before a second noun) is thought to be due to innate morphological constraints (Marcus, Brinkmann, Clahsen, Weise, & Pinker, 1995). Such constraints predict that all items of regular morphology should be treated differently from all items of irregular morphology by language users in all situations. However, if external factors such as input and response modality affect the number of plurals included in compounds, then this questions the internal constraint‐based explanations of compounding and encourages investigation of how external factors might influence the number of plurals included in compounds.
Retrieval‐induced forgetting is inversely relatedto everyday cognitive failures
Authors: Groome David , Grant Nina
Published: August 2005

It has recently been suggested (Anderson, 2003) that forgetting is an adaptive process arising from successful inhibition of unwanted items, rather than arising from a failure of the memory system. This inhibition process is thought to make use of retrieval‐induced forgetting (RIF). In the present study, individual susceptibility to RIF was measured in a group of 40 normal participants, whose RIF scores were then compared with their scores on the Cognitive Failures Questionnaire (CFQ). A significant inverse correlation was found between RIF and CFQ scores, indicating that individuals who show a strong RIF effect tend to suffer a lower rate of cognitive failures and forgetfulness in everyday life. These findings are consistent with the hypothesis that RIF might play a role in facilitating memory function by assisting selective retrieval.
Use of Proteomic Methods to Identify Serum Biomarkers Associated with Rat Liver Toxicity or Hypertrophy
Authors: Amacher David E , Adler Rick , Herath Athula , Townsend R Reid
Published: August 2005

Background: Our objectives were to identify serum marker proteins in rats that might serve as sensitive indicators of hepatomegaly, hepatocellular necrosis, or hepatobiliary injury and to use them to analyze data from a collaborative proteomics project.

Methods: In each of 4 studies comprising the collaborative project, rats were given 1 of 4 compounds that target the liver through different mechanisms. Sera and liver samples were collected by terminal bleeds at 1 of 3 postdose time points. Sera were depleted of major secretory proteins and then separated into protein features by 2-dimensional gel electrophoresis (2DGE). Liver specimens were also processed and subjected to 2DGE. Protein spots that significantly increased or decreased in quantity after drug treatment were recovered, digested, analyzed by mass spectroscopy, and compared with available databases for identification. Criteria for further consideration were (a) temporal expression (i.e., increase or decrease at early, fulminant, or recovery periods), (b) known biological function, (c) probable hepatic origin, and (d) any previous association with toxicity in published studies. Markers that changed significantly at the early time point were important because of their potential sensitivity for signaling minimal damage.

Results: Vitamin D–binding protein, paraoxonase, cellular retinol-binding protein, malate dehydrogenase, F-protein, and purine nucleoside phosphorylase were identified as empirically confirmed serum markers for hepatic effects in drug-treated rats.

Conclusion: Proteomics can be applied for the identification and confirmation of peripheral biomarkers for altered liver function after toxicant exposure.
Dielectric and Piezoelectric Properties of Niobium-modified BiInO3–PbTiO3 Perovskite Ceramics with High Curie Temperatures
Authors: Zhang Shujun , Xia Ru , Randall Clive A. , Shrout Thomas R. , Duan Runrun , Speyer Robert F.
Published: August 2005

Piezoelectric ceramics with TC > 500 °C were projected in the perovskite BiInO3–PbTiO3 (BIPT) system based on their low tolerance factor (∼0.884). However, a stable perovskite phase could be synthesized only when the PbTiO3 (PT) content was greater than 75%. Furthermore, the large tetragonality (c/a > 1.08) and low electrical resistivity made the ceramics difficult to pole. Niobium-modified BIPT ceramics with PT contents of 80% and 85% were found to possess significantly lower dielectric loss at elevated temperatures, making it possible to polarize the materials. Piezoelectric properties were measured for a BIPT85–1.5 mol% Nb composition with a Curie temperature of 542 °C; the longitudinal piezoelectric coefficient and coercive field were found to be 60 pC/N and 125 kV/cm, respectively.
Nanoindentation Method for Determining the Initial Contact and Adhesion Characteristics of Soft Polydimethylsiloxane
Authors: Cao Yifang , Yang Dehua , Soboyejoy Wole
Published: August 2005

In this paper, we present a method for determining the initial contact point and nanoindentation load–indentation depth characteristics for soft materials. The method is applied to the prediction of the load–indentation depth characteristics of polydimethylsiloxane. It involves the combined use of Johnson–Kendall–Roberts and Maugis–Dugdale adhesion theories and nonlinear least squares fitting in the determination of the initial contact point, the transition parameter, and the contact radius at zero contact load. The elastic modulus and the work of adhesion are also extracted from the load–indentation depth curves.
Nanoindentation Analysis of Mechanical Properties of Low to Ultralow Dielectric Constant SiCOH Films
Authors: Wang Lugen , Ganor M. , Rokhlin S.I. , Grill Alfred
Published: August 2005

Carbon-doped oxide SiCOH films with low to ultralow dielectric constants were prepared on a Si substrate by plasma-enhanced chemical vapor deposition (PECVD) from mixtures of SiCOH precursors with organic materials. The films have different levels of nanoscale porosity resulting in different dielectric constants and mechanical properties. The mechanical properties of the films have been characterized by continuous-stiffness nanoindentation measurements. To study the effect of film thickness, each group of samples with the same dielectric constant was composed of samples prepared with different film thicknesses. It is shown that the effective hardness and modulus of the SiCOH/Si substrate system depends significantly on indentation depth due to substrate constraint effects. The “true” film properties were determined using both an empirical formulation of the effective modulus and direct inversion based on a finite element model. The hardness and modulus of three groups of samples with different degrees of dielectric constants have been measured. The hardness increases from 0.7 to 2.7 GPa and modulus from 3.6 to 17.0 GPa as the dielectric constants change from 2.4 to 3.0. While for stiffer films the modulus measured at an indentation depth 10% of the film thickness is close to the “true” value for films thicker than 0.5 μm, the measured value can give an overestimate of up to 35% for softer films. Thin film cracking and film–substrate debonding have been observed with scanning electron and atomic force microscopy at the indentation sites in softer films. The damage initiation is indicated by pop-in events in the loading curve and sharp peaks in the normalized contact stiffness curves versus indentation depth.
Mechanical Properties of Intermetallic Compounds in the Au–Sn System
Authors: Chromik R.R. , Wang D-N. , Shugar A. , Limata L. , Notis M.R. , Vinci R.P.
Published: August 2005

The mechanical properties of intermetallic compounds in the Au–Sn system were investigated by nanoindentation. Measurements of hardness and elastic modulus were obtained for all of the confirmed room-temperature intermetallics in this system as well as the β phase (8 at.% Sn) and AuSn4. Overall, it was found that the Au–Sn compounds have lower hardness and stiffness than common Cu–Sn compounds found in solder joints. This finding is in contrast to common knowledge of “Au embrittlement” due to the formation of either AuSn4 or (Au,Ni)Sn4 intermetallic compounds. This difference in understanding of mechanical properties of these phases and the resulting joint strength is discussed in terms of reliability and possible failure mechanisms related to interface strength or microstructural effects. Indentation creep measurements performed on Au5Sn, Au–Sn eutectic (29 at.% Sn) and AuSn indicate that these alloys are significantly more creep resistant than common soft solders, in keeping with typical observations of actual joint performance.
Critical Examination of the Two-slope Method in Nanoindentation
Authors: Troyon M. , Huang L.
Published: August 2005

In this paper, we derive corrected analytical expressions for calculating the hardness and modulus by the two-slope method. This method relies on the determination of the slopes of the loading and unloading curves rather than the indenter displacement as an input. These expressions take into account the correction factor α in the fundamental relations among contact stiffness, elastic modulus, and contact area, which is frequently forgotten or misused in the literature. It is shown that these corrected expressions allow measurements of the hardness and modulus in very good agreement with the commonly used technique based on the determination of the contact area. Additionally, the correction factor α can be easily determined if Young's modulus of the material is known.
Effects of Cu Contents in Sn–Cu Solder on the Composition and Morphology of Intermetallic Compounds at a Solder/Ni Interface
Authors: Yu D.Q. , Wu C.M.L. , He D.P. , Zhao N. , Wang L. , Lai J.K.L.
Published: August 2005

The reaction between Sn–xCu (x = 0.1, 0.3, 0.7, 0.9, and 1.5 wt%) solder alloys and Ni at 260, 280, and 290 °C for 60 s was studied to reveal the effect of Cu content on the composition and morphology of intermetallic compounds (IMCs) formed at the interface between solder and substrate. The results indicated that Cu concentration greatly affects both the composition and morphology of the IMC between the solder and Ni substrate. In particular, when the Cu concentration was less than or equal to0.3 wt%, (CuxNi1−x)3Sn4 IMCs were formed at the interface. When the Cu concentration was 0.7 wt%, large facets type of (CuxNi1−x)6Sn5 were mixed with (CuxNi1−x)3Sn4 in the IMC layer. At Cu concentrations higher than the eutectic one, e.g., 0.9 and 1.5 wt%, stick-shaped (CuxNi1−x)6Sn5 compounds were detected, but the (CuxNi1−x)3Sn4 IMCs disappeared. The formation and growth mechanism of the (CuxNi1−x)6Sn5 compound were analyzed. The evolution tendency of the composition and morphology of the IMCs at the three testing temperatures was found to be the same.
Tensile Creep Behavior in Lutetia-doped Silicon Nitride Ceramics
Authors: Nishimura Toshiyuki , Hirosaki Naoto , Yamamoto Yoshinobu , Takigawa Yorinobu , Cao Jian-Wu
Published: August 2005

We studied tensile creep behavior in two silicon nitride ceramics, i.e., 4.8 mol% Lu2O3 (SN48) and 1.2 mol% Lu2O3 (SN12), at 1400–1500 °C under applied stress of 137–300 MPa. Time to failure of SN48 increased with decreasing applied stress and minimum strain rate. The stress–rupture parameter was 10.7 at 1400 °C and 11.4 at 1500 °C. Pore formation was confirmed in a creep-tested specimen of SN48 by transmission electron microscopy. These results suggest that SN48 was fractured by creep rupture. The minimum strain rate of SN12 was almost below the measurement system limitation at temperatures below 1500 °C. Time to failure tended to increase with decreasing applied stress. The stress–rupture parameter was 41 at 1400 °C and 73 at 1500 °C. These results suggest that SN12 was fractured by subcritical crack growth.
Thermoplastic vulcanizates based on poly(methyl methacrylate)/epoxidized natural rubber blends: Mechanical, thermal, and morphological properties
Authors: Nakason Charoen , Tobprakhon Akarapong , Kaesaman Azizon
Published: August 2005

Epoxidized natural rubbers (ENRs) with epoxide levels of 10, 20, 30, 40 and 50 mol % were prepared. The ENRs were later used to prepare thermoplastic vulcanizates (TPVs) by blending them with poly(methyl methacrylate) (PMMA) using various formulations. Dynamic vulcanization, using sulfur as a vulcanizing agent, was performed during the mixing process. The mixing torque increased as the ENR contents and epoxide molar percentage increased. This was because of an increasing chemical interaction between the polar groups of the blend components, particularly at the interface between the elastomeric and thermoplastic phases. The ultimate tensile strength of the TPVs with ENR‐20 was high because of strain‐induced crystallization. ENRs with epoxide levels >30 mol % exhibited an increase of tensile strength because of increasing levels of chemical interaction between the molecules and the different phases. The hardness of the TPVs also increased with increased epoxide levels but decreased with increased contents of ENRs. Two morphology phases with small domains of vulcanized ENR particles dispersed in the PMMA matrix were observed from scanning electron microscopy micrographs. The TPVs based on ENR‐20 and ENR‐50 showed smaller dispersed rubber domains than those of the other types of ENRs. Furthermore, the size of the vulcanized rubber domain decreased with increasing amounts of PMMA in the blends. The decomposition temperature of the TPVs also increased as both the levels of ENRs in the blends and the epoxide molar percentage increased. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1251–1261, 2005
Impedance spectra of carbon black filled high‐density polyethylene composites
Authors: Wang Yan‐Jie , Pan Yi , Zhang Xiang‐Wu , Tan Kai
Published: August 2005

Carbon black (CB) filled high‐density polyethylene (HDPE) composites are prepared by ordinary blending for use as an electrical conductive polymer composite. The composite changes from an electrical insulator to a conductor as the CB content is increased from 10 to 20 wt %, which is called the percolation region. For explanatory purposes, three models, namely, “conduction via nonohmic contacting chain,” “conduction via ohmic contacting chain,” and a mixture of them corresponding to the conductions in the percolation region, high CB loading region, and limiting high CB loading are proposed by the reasonable configurations of aggregate resistance, contact resistance, gap capacitance, and joining aggregates induction. The characters of the impedance spectra based on the three models are theoretically analyzed. In order to find some link between the electrical conductivity and the CB dispersion manner in the composites, the impedance spectra of three samples, HDPE/15 wt % CB (the center of the percolation region), HDPE/25 wt % CB (a typical point in the high CB loading region), and HDPE/19 wt % CB (the limiting high CB loading region), are measured by plotting the impedance modulus and phase angle against the frequency and by drawing the Cole–Cole circle of the imaginary part and real part of the impedance modulus of each sample. The modeled approached spectra and the spectra measured on the three samples are compared and the following results are found: the measured impedance spectrum of HDPE/15 wt % CB (percolation region) is quite close to the model of conduction via nonohmic contacting chain. The character of the measured spectrum of HDPE/25 wt % CB consists of the form of the model of conduction via ohmic contacting chain. The impedance behavior of HDPE/19 wt % CB exhibits a mixture of the two models. From the comparisons, it is concluded that the electrical conducting network in the percolation region of the CB filled HDPE composite is composed of aggregate resistance, nonohmic contact resistance, and gap capacitance, and that of the high CB loading region consists of continuously joined CB aggregate chains, which are possibly wound and assume helix‐like (not straight lines) conductive chains, acting as electrical inductions as the current passes through. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1344–1350, 2005
Changes of defensive functioning. does interpretation contribute to change?
Authors: Hersoug Anne Grete , Bøgwald Kjell‐Petter , Høglend Per
Published: August 2005

In this process–outcome study, we explored the changes of patients' defensive functioning (rated with the Defence Mechanism Rating Scales) over the course of brief dynamic psychotherapy (N= 39, maximum 40 sessions). We investigated whether therapists' use of interpretation (rated with the Psychodynamic Intervention Rating Scale) would influence the development of maladaptive defensive functioning. The proportion of maladaptive defences was reduced during therapy. A higher proportion of interpretation was associated with less use of maladaptive defence after therapy, whereas the use of interpretation was not predictive of the change of adaptive defensive functioning. Therapists' use of supportive interventions did not impact the development of either maladaptive or adaptive defences. Copyright © 2005 John Wiley & Sons, Ltd.
Is talking about an emotional experience helpful? effects on emotional recovery and perceived benefits
Authors: Zech Emmanuelle , Rimé Bernard
Published: August 2005

People generally share their emotions with others and believe that they will recover from their emotions after having talked about them. The aims of the present studies were to examine whether (1) talking about a specific emotional episode really facilitates emotional recovery (‘recovery’ effect) and (2) talking about emotions leads to perceived benefits (‘perceived benefits’). Consistently in the two studies, a decrease of emotional impact was found over time for participants in all conditions. Contrary to expectations, participants assigned to talk about their emotions did not demonstrate beneficial recovery effects at 3 or 7 days or 2 months compared with participants assigned to a factual description of the event (experiment 1), to the expression of another emotional event (experiment 2), to a trivial control condition (experiments 1 and 2) or to a non‐talking condition (experiment 2). However, in the two experiments, participants assigned to talk about negative emotional experiences reported more subjective benefits from the session than control participants. The role of personal beliefs about the effects of social sharing of emotion is discussed. Copyright © 2005 John Wiley & Sons, Ltd.
Xyloketal F: A Strong L‐Calcium Channel Blocker from the Mangrove Fungus Xylaria sp. (#2508) from the South China Sea Coast
Authors: Wu Xiong Yu , Liu Xiao Hong , Lin Yong Cheng , Luo Jing Hui , She Zhi Gang , Houjin Li , Chan Wing Lai , Antus Sándor , Kurtan Tibor , Elsässer Brigitta , Krohn Karsten
Published: August 2005

Xyloketal F (1), an unusual metabolite with strong L‐calcium channel blocking activity, was isolated from the mangrove endophytic fungus Xylaria sp. (#2508) collected at the South China Sea coast. Its structure was elucidated by spectral and single‐crystal X‐ray diffraction analysis. The absolute configuration of 1 was determined by the method of quantum‐mechanical calculation of CD spectra. Compound 1 was also synthesized by condensation of xyloketal B with formaldehyde. The L‐calcium channel blocking activities of xyloketals B, A, and F were determined, and at the same concentration (0.03 μmol/L), the inhibiting rates were 12.05 %, 21.47 %, and 50.33 % respectively. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Comparison of methanol and acetonitrile as solvents for the separation of sertindole and its major metabolites by capillary zone electrophoresis
Authors: Subirats Xavier , Reinstadler Sigrun , Porras Simo P. , Raggi Maria Augusta , Kenndler Ernst
Published: August 2005

Sertindole (1‐[2‐[4‐[5‐chloro‐1‐(4‐fluorophenyl)‐1H‐indol‐3‐yl]‐1‐piperidinyl]ethyl]‐2‐imidazolidinone), an atypical antipsychotic drug, was separated by capillary electrophoresis from its two main metabolites norsertindole and dehydrosertindole. The low solubility of the analytes in water (octanol‐water partition coefficient is about 105) is overcome by the use of methanol (MeOH) and acetonitrile (ACN) as solvents for the background electrolyte (BGE). Mobilities were measured in BGEs with defined pH in a broad range. It was found that in MeOH the mobility of the analytes is mainly governed by acid–base equilibria, whereas in ACN other reactions like ion pairing and homoconjugation play a pronounced role and lead to a complex pattern of the mobility as function of the pH. However, separation can be obtained in less than 10 min in both solvent systems.
Determination of hydrazine, monomethylhydrazine, 1,1‐dimethylhydrazine, and 1,2‐dimethylhydrazine by nonaqueous capillary electrophoresis with amperometric detection
Authors: Guo Lei , Matysik Frank‐Michael , Gläser Petra , Engewald Werner
Published: August 2005

The present study is concerned with the application of nonaqueous capillary electrophoresis (NACE) with electrochemical detection (ED) to the separation and quantitative determination of hydrazine (Hy) and its methyl derivatives. The best performance of NACE‐ED was found when using 4 mM sodium acetate/10 mM acetic acid/methanol: acetonitrile = 1:2 as the running buffer, with a bare platinum working electrode set at +1.0 V in an end‐column amperometric detection cell. The choice and ratio of suitable solvents for the separation and injection media played an essential role for the performance characteristics of the method. The limits of detection for Hy, methylhydrazine, symmetrical dimethylhydrazine, and unsymmetrical dimethylhydrazine were 5, 2, 12, and 1 ng/mL, respectively. This is between one and two orders of magnitude lower than that achieved by previously reported CE‐ED methods in aqueous buffer systems in conjunction with various types of chemically modified electrodes. The practical utility of the new NACE‐ED methodology is demonstrated in terms of the determination of traces of Hys in spiked environmental samples containing a wide range of explosives and related compounds.
Operator‐splitting method for real‐time substructure testing
Authors: Wu Bin , Xu Guoshan , Wang Qianying , Williams Martin S.
Published: August 2005

It has been shown that the operator‐splitting method (OSM) provides explicit and unconditionally stable solutions for quasi‐static pseudo‐dynamic substructure testing. However, the OSM provides only an explicit target displacement but not an explicit target velocity, so that it is essentially an implicit method for real‐time substructure testing (RST) when the velocity‐dependent restoring force is considered. This paper proposes a target velocity formulation based on the forward difference of the predicted displacements so as to render the OSM explicit for RST. The stability and accuracy of the resulting OSM‐RST algorithm are investigated. It is shown that the OSM‐RST is unconditionally stable so long as the non‐linear stiffness and damping are of the softening type (i.e. the tangent stiffness and damping never exceed the initial values). The stability of the OSM‐RST for structures with infinite tangent damping coefficient or stiffness is also proved, and the stability of the method for MDOF structures with a non‐classical damping matrix is demonstrated by an energy criterion. The effects of actuator delay and compensation are analysed based on the bilinear approximation of the actuator step response. Experiments on damped SDOF and MDOF structures verify that the stability of the OSM‐RST is preserved when the experimental substructure generates velocity‐dependent reaction forces, whereas the stability of real‐time substructure tests based on the central difference method is worsened by the damping of the specimen. Copyright © 2005 John Wiley & Sons, Ltd.
Differing strategies of patterning of follicular cells in higher and lower brachycerans (Diptera: Brachycera)
Authors: Tworzydlo Waclaw , Jablonska Anna , Kisiel Elzbieta , Bilinski Szczepan M.
Published: August 2005

In all higher dipterans (Brachycera), including the fruitfly, Drosophila melanogaster, each egg chamber (ovarian follicle) consists of a group (clone) of germ cells (one oocyte and 15 accompanying nurse cells) that is surrounded by a layer of somatic mesodermal follicular cells (FCs). As oogenesis progresses the initially uniform FCs diversify into several morphologically and functionally distinct subpopulations. In D. melanogaster some of these subpopulations, e.g., border, centripetal, and dorsolateral cells, undertake coordinated migration or rearrangement over the surface of the germ cells. During the final stages of oogenesis these subpopulations participate in the formation of a complex, regionally specialized eggshell. In representatives of lower brachycerans (Orthorrhapha), only FCs that undertake active, directed migration are the border cells. These cells originate at the anterior pole of the ovarian follicle and migrate between the nurse cells to the anterior pole of the oocyte. Reduced motility of FCs in lower brachycerans results in the absence of certain FC subpopulations in their egg chambers and subsequent simplicity of their eggshells. We found that the lack of some FC subpopulations coincided with the appearance of lamellipodium‐like protrusions of the oocyte. These protrusions penetrated between the apposing membranes of nurse and FCs and partially enveloped the nurse cell compartment. Analysis of whole‐mount preparations stained with rhodamine‐conjugated phalloidin revealed that the protrusions contained microfilaments and that their tips were equipped with actin‐rich filopodium‐like processes. We also found that in some lower brachycerans (representatives of the family Rhagionidae), the FCs located at the posterior pole of the oocyte, became enlarged and morphologically similar to the anterior border cells. These findings indicate that in higher dipterans the processes leading to the formation of a functional egg are variable and often markedly different from those in the model organism, D. melanogaster. genesis 43:49–58, 2005. © 2005 Wiley‐Liss, Inc.
Multi‐center nature of heterogeneous Ziegler–Natta catalysts: TREF confirmation
Authors: Kissin Yury V. , Mirabella Francis M. , Meverden Craig C.
Published: August 2005

A new approach to detailed Tref analysis of ethylene/α‐olefin copolymers prepared with multi‐center polymerization catalysts is developed. It is based on resolution of complex Tref curves into elemental components described with the Lorentz distribution function. This approach was applied to the study of a series of ethylene/1‐butene copolymers prepared with a supported Ti‐based catalyst. The analysis showed that the copolymers, which, on average, contain from 6.5 to 3.5 mol % of 1‐butene, consist of seven discrete components with different compositions, ranging from a completely amorphous material with a 1‐butene content of > 15–20 mol %, to two highly crystalline components with 1‐butene contents < 1 mol %. A comparison of these Tref results with the data on the molecular weight distribution of the copolymers (based on resolution of their GPC curves) shows that Tref and GPC data provide complimentary information on the properties of active centers in the catalysts in terms of the molecular weights of the material they produce and their ability to copolymerize α‐olefins with ethylene. Tref analysis of copolymers produced at different reaction times showed that the active centers responsible for the formation of various Tref components differ in the rates of their formation and in stability. The centers that produce copolymer molecules with a high 1‐butene content are formed rapidly but decay rapidly as well whereas the centers producing copolymer molecules with a low 1‐butene content are formed more slowly but are more stable. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4351–4362, 2005
Anionic polymerization of methyl methacrylate by initiating systems based on lithium amides of various secondary amines
Authors: Ihara Eiji , Omura Naohiro , Tanaka Shinsuke , Itoh Tomomichi , Inoue Kenzo
Published: August 2005

The anionic polymerization of methyl methacrylate in toluene at −78 °C with lithium amides of various secondary amines (diisopropylamine, N‐isopropylaniline, N‐n‐butylaniline, indoline, and N‐ethyl‐o‐toluidine) as initiators was studied. The tacticity of the resulting poly(methyl methacrylate)s (PMMAs) was dependent on the kind of secondary amine, and highly isotactic PMMAs (91–93% mm) were obtained when lithium amides of N‐isopropylaniline and N‐n‐butylaniline were employed. The isotacticity of the PMMAs further increased up to 98% mm with initiating systems composed of the lithium amides, n‐butyllithium, and transition‐metal halides (WCl6, MoCl5, and NbCl5). © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4405–4411, 2005
Synthesis and characterization of poly[styrene‐b‐methyl(3,3,3‐trifluoropropyl)siloxane] diblock copolymers via anionic polymerization
Authors: Yi Lingmin , Zhan Xiaoli , Chen Fengqiu , Du Feng , Huang Linbing
Published: August 2005

A series of narrow molecular weight distribution (MWD) polystyrene‐b‐poly[methyl(3,3,3‐trifluoropropyl)siloxane] (PS‐b‐PMTFPS) diblock copolymers were synthesized by the sequential anionic polymerization of styrene and trans‐1,3,5‐trimethyl‐1,3,5‐tris(3′,3′,3′‐trifluoropropyl)cyclotrisiloxane in tetrahydrofuran (THF) with n‐butyllithium as the initiator. The diblock copolymers had narrow MWDs ranging from 1.06 to 1.20 and number‐average molecular weights ranging from 8.2 × 103 to 37.1 × 103. To investigate the properties of the copolymers, diblock copolymers with different weight fractions of poly[methyl(3,3,3‐trifluoropropyl)siloxane] (15.4–78.8 wt %) were prepared. The compositions of the diblock copolymers were calculated from the characteristic proton integrals of 1H NMR spectra. For the anionic ring‐opening polymerization (ROP) of 1,3,5‐trimethyl‐1,3,5‐tris(3′,3′,3′‐trifluoropropyl)cyclotrisiloxane (F3) initiated by polystyryllithium, high monomer concentrations could give high polymer yields and good control of MWDs when THF was used as the polymerization solvent. It was speculated that good control of the block copolymerization under the condition of high monomer concentrations was due to the slowdown of the anionic ROP rate of F3 and the steric hindrance of the polystyrene precursors. There was enough time to terminate the ROP of F3 when the polymer yield was high, and good control of block copolymerization could be achieved thereafter. The thermal properties (differential scanning calorimetry and thermogravimetric analysis) were also investigated for the PS‐b‐PMTFPS diblock copolymers. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4431–4438, 2005
Cognitive impairment associated with adjuvant therapy in breast cancer
Authors: Bender Catherine M. , Sereika Susan M. , Berga Sarah L. , Vogel Victor G. , Brufsky Adam M. , Paraska Karen K. , Ryan Christopher M.
Published: August 2005

The purpose of this study was to determine whether cognitive function changes over time in women with breast cancer who received adjuvant therapy as compared to women with breast cancer who received no adjuvant therapy. Three groups of women (n=46) were studied; groups 1 and 2 consisted of women with stage I or II breast cancer. Group 1 received chemotherapy and group 2 received chemotherapy plus tamoxifen. Group 3 consisted of women with ductal carcinoma in situ who received no chemotherapy or tamoxifen. Cognitive function was evaluated at three timepoints. Time 1 occurred after surgery and before chemotherapy initiation in groups 1 and 2. Time 1 for group 3 occurred post‐surgery. Time 2 occurred within 1 week after the conclusion of chemotherapy for groups 1 and 2 and at a comparable time for group 3. Time 3 occurred 1 year after Time 2. Women who received chemotherapy plus tamoxifen exhibited deterioration on measures of visual memory and verbal working memory and reported more memory complaints. Women who received chemotherapy alone also exhibited deteriorations in verbal working memory. Conversely, cognitive function scores improved in women who received no therapy, indicating practice effects. In conclusion, adjuvant chemotherapy in women with breast cancer can be associated with deteriorations in memory and this may persist over time. The addition of tamoxifen may lead to more widespread memory deficits. Copyright © 2005 John Wiley & Sons, Ltd.