bluuebunny/crossref_metadata_2025 huggingface dataset:
Political and Demographic Foundations for Sectionalism in State Politics
Authors: Gimpel James G. , Schuknecht Jason E.
Published: April 2003

Defined in terms of partisanship, substate sectionalism remains pervasive within many states, although it is probably not a constant, even in the short term. Here we ask about the forces that are responsible for producing substate sectionalism as evidenced by support for the two major parties. Using a geographic statistic as our indicator, we evaluate the degree of sectionalism over time in Connecticut presidential and gubernatorial elections. Population trends have increased the extent of sectionalism in the state mainly by exacerbating inequalities between deindustrializing cities in Central Connecticut and prosperous, growing ones in Fairfield County. The growth of the Black population is associated with increasing regionalism in both sets of elections given that the African American population remains concentrated in the largest cities. The study of sectionalism in Connecticut helps us to specify how population growth and redistribution contribute to the political geography of state politics.
Tapping Motives and Dynamics behind Campaign Contributions
Authors: Cho Wendyk. Tam
Published: April 2003

Campaign donors are sometimes characterized as investors who carefully allocate their financial resources to candidates and/or political action committees to maximize their influence. Although this theory has some veracity, it does not adequately describe all contributors. The patterns of Asian American contributions imply that their interests are strongly tied to ethnicity rather than to alternative influence-maximizing strategies. Indeed, contrary to popular belief, Asian Americans predominantly fund candidates of their own ethnicity. The campaign finance data are virtually devoid of pan-Asian coalitions. A detailed study of the behavior of Asian American donors is useful in its own right. More important, an accurate portrait of the Asian American donor highlights the crudeness of a strictly rational sketch of campaign contributors and adds to our understanding of the logic behind political behavior.
Tracking the Filibuster, 1917 to 1996
Authors: Binder Sarah A. , Lawrence Eric D. , Smith Steven S.
Published: April 2003

Scholars and observers of the U.S. Senate have noted an appreciable rise in the use of the filibuster over the course of the 20th century. Although numerous explanations have been offered, alternative accounts have never been pitted against each other in a multivariate fashion. In this article, we survey and test these multiple accounts, using data on filibusters launched between 1917 and 1996. Our findings suggest that the incentive to filibuster is predictably shaped by both partisan preferences and institutional opportunity, findings that hold even before the marked rise in partisanship evident at late century.
Overreporting And Electoral Participation Research
Authors: Cassel Carol A.
Published: April 2003

Do nonvoters who say they voted bias electoral participation research? Early studies said they do not, but Bernstein, Chadha, and Montjoy concluded that overreporters alter the effects of most independent variables. This research tests whether overreporters bias conclusions about additional untested variables and whether we obtain the same results as Bernstein and his coauthors when we test different models. Overreporters bias the coefficients of only a small proportion of independent variables in more typical models, although overreporting is more problematic than the early studies reported. Specifically, in the models this research tests, overreporters change the effects of African American race, marital status, Southern residence, and closing date on presidential election turnout and African American race, marital status, Hispanic ethnicity, occupation, and open seat races on midterm turnout. A warning about how overreporting bias affects, or may affect, their conclusions should accompany studies that include these, or other,untested variables.
Neuronal Nicotinic Acetylcholine Receptors: Involvement in Alzheimer’s Disease and Schizophrenia
Authors: Woodruff-Pak Diana S. , Gould Thomas J.
Published: April 2003

Nicotinic acetylcholine receptors (nAChRs) play a role in a variety of diseases of the central nervous system including Alzheimer's disease (AD) and schizophrenia. There is great interest in evaluating disease-related nAChR changes, and pharmacological treatment of nAChR deficits is a promising therapy. In AD, 7 nAChRs remain relatively stable, contrasting to 4 2 nAChRs that are lost in substantial numbers. -amyloid, a major neuropathology in AD, blocks 4 2 and 7 nAChRs. Agonists selective to 7 nAChRs are neuroprotective against amyloid. Paradoxically, 7 nAChRs may function as receptors for -amyloid. These results indicate 7 nAChR antagonists may be appropriate therapy in AD. In schizophrenia, 7 nAChRs are significantly reduced in hippocampus and neocortex. The exceptionally high rate of smoking in schizophrenics is likely a form of self-medication. Therapy with 7 nAChR agonists relieves some schizophrenic symptoms. Despite disparities in etiology and symptomatology, AD and schizophrenia share a target for therapeutic intervention— 7 nAChRs.
Neural Systems for Perceptual Skill Learning
Authors: Poldrack Russell A.
Published: April 2003

Recent studies have begun to use functional neuroimaging techniques to examine the changes in brain activity that occur as humans learn new skills. This review outlines results from a number of imaging studies examining visual perceptual skill learning. Although the regions engaged during skill learning differ across tasks, a common finding has been increasing activation in the inferior temporal and fusiform gyri as skill is acquired and activation of the caudate nucleus in association with learning. Neuroimaging has great promise for the understanding of learning at the level of large neural populations, but further work is necessary to understand the specificity of learning-related changes and their relation to underlying neurophysiological plasticity.
Memory in Neuroscience: Rhetoric Versus Reality
Authors: Wolpaw Jonathan R.
Published: April 2003

The central point of this article is that the concept of memory as information storage in the brain is inadequate for and irrelevant to understanding the nervous system. Beginning from the sensorimotor hypothesis that underlies neuroscience—that the entire function of the nervous system is to connect experience to appropriate behavior—the paper defines memories as sequences of events that connect remote experience to present behavior. Their essential components are (a) persistent events that bridge the time from remote experience to present behavior and (b) junctional events in which connections from remote experience and recent experience merge to produce behavior. The sequences comprising even the simplest memories are complex. This is both necessary—to preserve previously learned behaviors—and inevitable—due to secondary activity-driven plasticity. This complexity further highlights the inadequacy of the information storage concept and the importance of extreme simplicity in models used to study memory.
A Neurobehavioral Examination of Individuals with High-Functioning Autism and Asperger’s Disorder Using a Fronto-Striatal Model of Dysfunction
Authors: Rinehart Nicole J. , Bradshaw John L. , Tonge Bruce J. , Brereton Avril V. , Bellgrove Mark A.
Published: April 2003

The repetitive, stereotyped, and obsessive behaviors that characterize autism may in part be attributable to disruption of the region of the fronto-striatal system, which mediates executive abilities. Neuropsychological testing has shown that children with autism exhibit set-shifting deficiencies on tests such as the Wisconsin Card Sorting task but show normal inhibitory ability on variants of the Stroop color-word test. According to Minshew and Goldstein’s multiple primary deficit theory, the complexity of the executive functioning task is important in determining the performance of individuals with autism. This study employed a visual-spatial task (with a Stroop-type component) to examine the integrity of executive functioning, in particular inhibition, in autism ( n= 12) and Asperger’s disorder ( n= 12) under increasing levels of cognitive complexity. Whereas the Asperger’s disorder group performed similarly to age and IQ-matched control participants, even at the higher levels of cognitive complexity, the high-functioning autism group displayed inhibitory deficits specifically associated with increasing cognitive load.
Semantic Retrieval, Mnemonic Control, and Prefrontal Cortex
Authors: Badre David , Wagner Anthony D.
Published: April 2003

Accessing stored knowledge is a fundamental function of the cognitive and neural architectures of memory. Here, the authors review evidence from cognitive-behavioral paradigms, neuropsychological studies ofpatients with focal neural insult, and functional brain imaging concerning the mechanisms underlying retrieval ofsemantic knowledge and their association with prefrontal cortex. First, the authors examine behavioral and neuropsychological evidence distinguishing between controlled and automatic semantic retrieval. Then the authors review the subregions of prefrontal cortex that functional neuroimaging has associated with semantic retrieval across a range ofmemory demanding tasks. Finally, two hypotheses concerning the nature ofprocessing in these brain regions–the controlled semantic retrieval and selection hypotheses–are critically examined, and a possible synthesis is proposed.
The Use of Lacanian Psychoanalysis in a Case of Fetishism
Authors: Fink Bruce
Published: April 2003

The work described in this article was based on the long-term treatment approach developed by Jacques Lacan, the French psychoanalyst (1901-1981). It provides a first formulation (after about 4 years) of an ongoing case, which has been conducted exclusively by telephone. The myriad significations of a particular fetish object are drawn out and tied to the participant's history, and evolution of the fetish during the course of the analysis is described.
Debridement of the Diabetic Foot: A Podiatric Perspective
Authors: Baker Neil
Published: April 2003

High plantar pressures are a risk factor for diabetic foot ulcers that are common chronic wounds. In patients with peripheral neuropathy, plantar ulcers may be managed by debridement of callus, a process that has been shown to reduce peak plantar pressures. Callus debridement is clearly an important ulcer prevention strategy. The scalpel skills used by the podiatrist to remove callus are best suited to achieve safe, local sharp wound debridement. Current podiatric practice in the United Kingdom is based on sound theoretical principles. However, good scientific data recommending its efficacy are scarce. The role of podiatry in debridement and wound management needs careful examination, a major aim of this article.
Phantom Limb Pain—A Complication of Lower Extremity Wound Management
Authors: Hazelgrove Jane F. , Rogers Peter D.
Published: April 2003

Amputation is one treatment option for patients with critical limb ischemia, diabetic foot wounds, and occasionally, even venous leg ulcers. Amputation of the whole limb or part of it or the digits can cause complications including pain. Post-amputation pain, and especially phantom limb pain (PLP), is a poorly understood phenomenon. Effective management of established pain is a major challenge. This reviewis for wound workers who are a multiprofessional group. Any amputated limb, appendage, or viscera can be affected by PLP, though the focus of this article will be the treatment of PLP following limb loss. The pathophysiology is still not fully understood. The size of the problem of PLP, possible underlying physiological mechanisms, and potential preventative measures are presented in this article.
Change Is Complex: Rethinking Research on Psychosocial Interventions and Cancer
Authors: Temoshok Lydia R. , Wald Rebecca L.
Published: April 2003

The widely discussed 1989 study by Spiegel and colleagues, which suggested that a psychosocial group intervention affected survival in metastatic breast cancer, was not replicated by Goodwin and colleagues in 2001. We analyze methodological issues in both studies, including issues of sampling, randomization, interpretation, and the adequacy and validity of psychosocial constructs and measures to assess hypothesized ingredients of change. The notion of psychogenicityis introduced, conceived as the ability of psychosocial interventions to elicit changes hypothesized to be linked to desired medical outcomes. These considerations lead to the conclusion that there is insufficient evidence to be able to generalize from either study for or against the notion that psychosocial interventions can affect survival in breast cancer. The failure to incorporate into research designs a comprehensive understanding of how coping patterns and related factors may interact with psychosocial interventions to influence cancer progression, and to address hypothesized mediating mechanisms is discussed. Finally, strategies are proposed for future biopsychosocial and intervention research in the field of biopsychooncology.
Interactive Guided Imagery SM as a Way to Access Patient Strengths During Cancer Treatment
Authors: Rossman Martin L.
Published: April 2003

In cancer care, there are 2 complementary goals of treatment: eliminating cancer cells and supporting the well-being and healing abilities of the patient. Interactive Guided Imagerysm(IGI) can be used to help the patient access inner strengths and resources when high anxiety levels may make that difficult. Three brief cases illustrate the use of IGI to help patients access a “big picture” perspective on their treatment and healing path; to find strength to persevere in their treatment course; and to help make a difficult decision. In all 3 cases, there are multiple personal benefits of the imagery that continued to be of importance throughout the course of each patient’s treatment.
Attachment and Cancer: A Conceptual Integration
Authors: Tacón Anna M.
Published: April 2003

Cancer traditionally has been explained by the biomedical model; however, it is limited in comprehensively accounting for all factors in this disease. Recently, it has been suggested that a broader theoretical framework that includes psychosocial components in cancer is needed to complement the traditional approach. The purpose of this article, therefore, is to explore the utility of attachment theory as a biopsychosocial model of both development and health. Attachment, a developmental theory, explains how repeated interactions between caregiver and child in the early years establish lifelong psychosocial, physiological, affective, and cognitive patterns as well as enduring patterns of stress response to threat or illness. Despite attachment theory’s biopsychosocial foundation, the application of attachment security as a factor in physical health and psychosomatic medicine is relatively recent. The current work reviews attachment theory and psychosocial literature with regard to cancer and follows with a novel attempt to conceptually integrate both bodies of literature. A concluding integrative model of attachment theory and the type C behavior pattern is provided to illustrate potential links and integrative processes that may lead to disease resilience or vulnerability.
Becoming Maestra: Latina Paraprofessionals as Teacher Candidates in Bilingual Education
Authors: Rintell Ellen M. , Pierce Michelle
Published: April 2003

In a qualitative evaluation of a college paraeducator-to-bilingual-teacher program, participants talked about life experiences that contributed to their commitments to teaching and what helped and encouraged them to be successful in their academic work. Some themes that emerged were previous education in participants' home countries, involvement in their children's school experiences, the respect they received from professors, the support of their families, and the opportunity to be role models to their children.
School Social Context Effects on Gender Differences in Academic Achievement Among Second-Generation Latinos
Authors: Rodríguez Tomás D.
Published: April 2003

This study considers involuntary minority concentration effects on gender differences in achievement and finds increasing levels of involuntary minority enrollments decrease grade point averages and math scores for immigrant boys versus girls, net of individual and school socioeconomic status. Immigrant achievement declines in involuntary minority schools where a climate of apathy and failure inhibits performance. Yet, differences in gender roles and socialization renders girls less vulnerable to assimilation of adversarial attitudes and behaviors responsible for academic failure.
Echocardiography of an Isolated Distal Coronary Artery Aneurysm in an Older Child with Kawasaki Disease
Authors: Wallace Tracy , Wallace Andy
Published: April 2003

The etiology of Kawasaki disease (KD) is un-known. Typically, it affects children 5 years old or younger. It has also been diagnosed in older children and adolescents. One of the most serious and common complications is the development of coronary artery aneurysm(s). The following is a case report showing transthoracic echocardiography as an effective, noninvasive method to evaluate the coronary arteries in children. It is beneficial in the event of an isolated distal coronary artery aneurysm as seen in this case.
Lower Extremity Sonography Detects Complex Mass
Authors: Corrao Debbie , Schultz Steven M.
Published: April 2003

Popliteal cysts, also known as Baker’s cysts, are the most common benign mass of the knee. Dissecting or ruptured Baker’s cysts into and about the perifascial planes of the gastrocnemius and soleus muscles of the calf produces a swollen, painful limb that mimics deep venous thrombosis. The author presents a case of a complicated dissecting popliteal cyst followed by serial sonography and magnetic resonance imaging.
Study of the impact of blood lead level on humoral immunity in humans
Authors: Ayatollahi M ohammad
Published: April 2003

The objective was to study the impact of blood lead level (BLL) on serum immunoglobulin levels (SIL; IgG, IgM, IgA) in people with high-risk professions. It has been characterized that BLL / 25 g/dL can cause dysfunctions in different organ systems of the body, such as the immune system. A cross-sectional study was carried out in relation to this, by using a pretested questionnaire to collect data on demographic factors and socioeconomic status, which was completed by subjects studied, such as car battery shop workers, car painters and welders of car radiators and exhausts, printing office workers (typesetters and nontypesetters) who were aged between 15 and 70 years. Venous blood was sampled to measure the BLL (by atomic absorption spectroscopy) and SIL (by SRID). The results, when analysed, suggested a reduction in SIL with emphasis on IgG in comparison with standard levels.
Nigella sativa (black cumin) ameliorates potassium bromate-induced early events of carcinogenesis: diminution of oxidative stress
Authors: Khan Naghma , Sharma Sonia , Sultana Sarwat
Published: April 2003

Potassium bromate (KBrO3) is a potent nephrotoxic agent. In this paper, we report the chemopreventive effect ofNigella sativa (black cumin) on KBrO3-mediated renal oxidative stress, toxicity and tumor promotion response in rats. KBrO3 (125 mg/kg body weight, intraperitoneally) enhances lipid peroxidation, g-glutamyl transpeptidase, hydrogen peroxide and xanthine oxidase with reduction in the activities of renal antioxidant enzymes and renal glutathione content. A marked increase in blood urea nitrogen and serum creatinine has also been observed. KBrO3 treatment also enhances ornithine decarboxylase (ODC) activity and [3H] thymidine incorporation into renal DNA. Prophylaxis of rats orally with Nigella sativaextract (50 mg/kg body weight and 100 mg/kg body weight) resulted in a significant decrease in renal microsomal lipid peroxidation (P B-00.001), g-glutamyl transpeptidase (P B-0.001), H2O2 (P B-0.001) and xanthine oxidase (P B-0.05). There was significant recovery of renal glutathione content (P B-0.01) and antioxidant enzymes (P B-0.001). There was also reversal in the enhancement of blood urea nitrogen, serum creatinine, renal ODC activity and DNA synthesis (P B-0.001). Data suggest that Nigella sativa is a potent chemopreventive agent and may suppress KBrO3-mediated renal oxidative stress, toxicity and tumour promotion response in rats.
Some remarks on the use of isothermal thermogravimetric data for the evaluation of kinetic parameters. Applications for degradation of polymeric materials
Authors: Budrugeac P. , Segal E. , Popescu C.
Published: April 2003

A critical analysis of the isoconversional methods for evaluating kinetic parameters of decomposition of solids from isothermal thermogravimetric data is presented. An isoconversional integral method to evaluate the activation energy is suggested. This method allows removing the errors due the correction of the degradation time by subtracting the induction period to onset of the main reaction (also including the time required to heat the sample to the temperature at which the isotherm is recorded). This procedure was used to study the degradation of two series of polymeric materials, (a) poly(vinyl chloride)/acrilonitrile–butadiene–styrene (PVC/ABS) blends and (b) poly(vinyl chloride)/chlorinated poly(ethylene) (PVC/CPE) blends. The values obtained for the activation energy are in fairly good agreement with those obtained from the Prout–Tompkins model in case (a) and from nonisothermal data in case (b). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 355–360, 2003
Study of rheological property of nylon‐1212 with Haake Rheometer
Authors: Zhang Chenggui , Liu Minying , Zhao Qingxiang , Wang Yudong , Liu Songtao
Published: April 2003

Rheological properties of nylon‐1212 have been studied by means of Haake Rheometer. The effect of shear rate and temperature on the apparent vicosity of nylon‐1212 was discussed. A correlation of non‐Newtonian index with the temperature was obtained. The results showed that the apparent viscosity decreases with the increase of the temperature. With increasing shear rate, shear thinning of nylon‐1212 was observed clearly. From the relation of the temperature dependence of the polymer, we obtained the viscous flow activation energy. We conclude that the apparent viscosity is sensitive to temperature at lower shear stress because of higher viscous flow activation energy, and the temperature affect on the apparent viscosity becomes weaker at higher shear stress because of lower viscous flow activation energy. We have investigated the creep and elastic recovery of nylon‐1212. A creep test was carried out to define the linear viscoelastic range as 1.0 and 5.0 Pa for 195 and 190°C nylon‐1212 melts, respectively. A time‐dependent response was found for the creep and recovery phases at a lower applied shear stress. However, at higher shear stress, the creep and recovery phases were time‐independent. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 379–385, 2003
Cocontinuous morphologies in polystyrene/ethylene–vinyl acetate blends: The influence of the processing temperature
Authors: Moreira Ana Cristina F. , Cario Francisco O. , Soares Bluma G.
Published: April 2003

The influence of the compression‐molding temperature on the range of cocontinuity in polystyrene (PS)/ethylene–vinyl acetate (EVA) copolymer blends was studied. The blends presented a broad range of cocontinuity when compression‐molded at 160°C, and they became narrower when compression‐molded at higher temperatures. A coarsening effect was observed in PS/EVA (60:40 vol %) blends upon compression molding at higher temperature with an increase in the phase size of the cocontinuous structure. Concerning PS/EVA (40:60 vol %) blends, an increase in the mixing and molding temperatures resulted in a change from a cocontinuous morphology to a droplet–matrix morphology. This effect was observed by selective extraction experiments and scanning electron microscopy. The changes in the morphology with the molding conditions affected the storage modulus. An increase in the storage modulus in blends compression‐molded at 160°C was observed as a result of dual‐phase continuity. An EVA copolymer with a higher vinyl acetate content (28 wt %) and a higher melt‐flow index resulted in blends with a broader range of cocontinuity. This effect was more pronounced in blends with lower amounts of PS, that is, when EVA formed the matrix. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 386–398, 2003
Statistical and kinetic approaches for linear low‐density polyethylene melting modeling
Authors: Greco A. , Maffezzoli A.
Published: April 2003

The aim of this study was to compare different models, either originating from literature or originally proposed in this study, for the interpretation of the melting behavior of polymers. In particular, these models, tested with a linear low‐density polyethylene widely used in rotational molding, are suitable for coupling with energy balances in the study of polymer processing. We obtained the experimental data from differential scanning calorimetry (DSC) dynamic scans, assuming that the endothermic flux was related to the rate of melting of the polymer. The studied models were able to predict the broad melting temperature range typically observed during polymer melting with either a statistical or a kinetic approach. The two different approaches were compared with experimental DSC data. The analysis of model performances with complex thermal programs showed that the statistical approach could provide a more realistic representation of polymer melting. These models were particularly suitable in rotational molding, where the lack of any flow and, hence, of any crystalline orientation leads to a degree of melting determined by the actual temperature of the polymer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 289–295, 2003
Preparation of water‐repellent silks by a reaction with octadecenylsuccinic anhydride
Authors: Arai Takayuki , Freddi Giuliano , Innocenti Riccardo , Tsukada Masuhiro
Published: April 2003

Silk fibers and membranes were acylated with octadecenylsuccinic anhydride (ODSA) at 75°C for different times. Swelling [N,N‐dimethylformamide (DMF) and dimethyl sulfoxide (DMSO)] and nonswelling (xylene) solvent media were used for the reaction. Silk membranes that reacted in DMF or DMSO displayed faster reaction kinetics and attained higher weight‐gain values than fibers. The effect of the solvent on the reaction yield was in the following order: DMSO > DMF ≫ xylene. The Fourier transform infrared spectra of acylated silk samples showed the characteristic absorption bands of the anhydride at 2990, 2852, 1780–1700, and 1170 cm−1. The intensity of the latter band, which increased linearly with the weight gain, was used as a marker for evaluating the reaction kinetics of the samples acylated in the nonswelling medium. The moisture regain and water retention of silk fibers acylated with ODSA decreased significantly, regardless of the solvent system used. Accordingly, the water repellency increased. Acylation induced an increase in the thermal stability of the silk fibers and membranes. Fine particles adhering to the surfaces of the silk fibers acylated in xylene were detected by scanning electron microscopy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 324–332, 2003
Pervaporation separation of water and dioxane mixtures with sodium alginate‐g‐polyacrylamide copolymeric membranes
Authors: Kurkuri Mahaveer D. , Aminabhavi Tejraj M.
Published: April 2003

Polyacrylamide (pAAm)‐grafted sodium alginate (NaAlg) copolymeric membranes have been prepared and used in the pervaporation separation of dioxane mixtures containing10–70 mass % water. Three different polymeric membranes have been prepared: neat NaAlg, 46% grafted pAAm‐g‐NaAlg, and 93% grafted pAAm‐g‐NaAlg. For reduced brittleness and increased flexibility of the membranes, 10 mass % poly(ethylene glycol) and 5 mass % poly(vinyl alcohol) were added to all three membranes. With the transport data for the mixtures through the membranes, the permeation flux, selectivity, pervaporation separation index, swelling index, and diffusion coefficients have been calculated at 30°C. The Arrhenius activation parameters for the transport processes have been calculated for 10 mass % water in the feed mixture with flux and diffusion data obtained at 30, 40, and 50°C. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 300–305, 2003
Hemodialysis membrane prepared from cellulose/N‐methylmorpholine‐N‐oxide solution. II. Comparative studies on the permeation characteristics of membranes prepared from N‐methylmorpholine‐N‐oxide and cuprammonium solutions
Authors: Abe Yoshihiko , Mochizuki Akira
Published: April 2003

Two kinds of regenerated cellulose membranes for hemodialysis were prepared from casting solutions of N‐methylmorpholine‐N‐oxide (NMMO) and cuprammonium (denoted NMMO membranes and cuprammonium membranes, respectively). The concentration of cellulose in the casting solution investigated was 6–8 wt %. The permeation characteristics of both membrane series were compared in terms of the ultrafiltration rate (UFR) of pure water, the sieving coefficient (SC) of dextran, and the solute permeabilities of urea, creatinine, and vitamin B12. The UFR and SC of the NMMO membranes were strongly affected by the cellulose concentration of the casting solution, and NMMO was a preferable solvent for the production of cellulose membranes with high performance; the cuprammonium solution gave low‐performance membranes. The pore structures of both types of membranes were estimated with the Hagen–Poiseuille law. The results showed that the NMMO membranes had larger pore radius and smaller pore numbers than the cuprammonium membranes. The differences in the membrane pore structures led to the differences in the performance between the two membrane series. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 333–339, 2003
Ionic conductivity and related properties of crosslinked chitosan membranes
Authors: Wan Ying , Creber Katherine A. M. , Peppley Brant , Bui V. Tam
Published: April 2003

Crosslinked chitosan membranes were prepared with a relatively low degree of crosslinking with epichlorohydrin and glutaraldehyde as crosslinking agents under heterogeneous and homogeneous conditions, respectively. The tensile properties, crystallinity, swelling index, and ionic conductivity of the crosslinked membranes were investigated. A significant decrease in the crystallinity and a large change in the swelling ratio of the crosslinked membrane were observed. In comparison with the uncrosslinked chitosan membrane, when the chitosan membrane was crosslinked with an appropriate degree of crosslinking under homogeneous conditions, its ionic conductivity after hydration for 1 h at room temperature increased by about one order of magnitude. In addition, with a lower concentration of the crosslinking agent, the tensile strength and breaking elongation of the crosslinked membrane were almost unchanged. Moreover, up to a critical value, the tensile strength of the membrane increased gradually, and the breaking elongation decreased slowly. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 306–317, 2003
Study on kinetics of polymer melt intercalation by a rheological approach
Authors: Li Jian , Zhou Chixing , Wang Gang , Zhao Delu
Published: April 2003

The kinetics of melt intercalation of poly(propylene)/montmorillonite nanocomposites was studied by a rheological approach. The experimental sample was elaborately prepared to investigate the whole intercalating process. The intercalation process was demonstrated by the changes of the viscoelastic response with annealing time. The development of the relative volume fraction of intercalated tactoids was obtained from the rheological characterization. The apparent diffusivities was determined and the activation energy of melt intercalation was found to be about 80 ± 6 kJ/mol. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 318–323, 2003
Electrostrictive effect in polyurethanes
Authors: Guillot F.M. , Balizer E.
Published: April 2003

Polyurethane electrostriction was investigated by measuring the tensile electromechanical coupling coefficients of structurally different materials. True values of the strain coefficients M3311, M3322, and M3333 were obtained for four types of polymer: one commercial polyurethane (DOW 2103‐80 AE) and three polyurethanes synthesized at the Naval Surface Warfare Center, including two phase‐separated (PS) materials with molecular weights of 1000 and 2000 and one phase‐mixed (PM) material with a molecular weight of 2000. Measurements were performed at 2 kHz under a bias field of 4 MV/m at room temperature. Measured values of M3333 ranged from −9.4 × 10−18 to −74.6 × 10−18 m2/V2, with the PM material exhibiting the largest coefficient. The electrostatic interaction (Maxwell stress) did not account for more than 15% of the total electromechanical activity in any of the materials. Furthermore, at the macroscopic level, an empirical relationship was established to predict the values of the electrostrictive coefficients from the dielectric constants and the compliance coefficients of the material. Finally, results indicated that, at the microscopic level, the phenomenon of electrostriction in polyurethanes could be best explained by the presence of charges inside the material (space–charge theory). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 399–404, 2003
Morphology control in polysulfone‐modified epoxy resins by demixing behavior
Authors: Giannotti M. I. , Solsona M. S. , Galante M. J. , Oyanguren P. A.
Published: April 2003

Polysulfone (PSu) was used as a modifier of epoxy/aromatic diamine formulations. Two epoxy monomers, based on diglycidyl ether of bisphenol A (DGEBA), were used. The cure agent was 4,4′‐diaminodiphenylsulfone. PSu was miscible with DGEBA, as shown by the existence of a single glass‐transition temperature within the whole composition range. The effect of PSu addition on the cure kinetics was investigated. The reaction rate of the epoxy–amine species was slightly lower in the presence of PSu. The morphology was analyzed by optical and scanning electron microscopy. A range of microstructures were obtained by control over the cure temperature, the amount of PSu incorporated, and the molecular weights of the epoxy resins. The variations in the morphology resulted from the different stages of demixing, which were arrested because of the different developments of the viscosity of the system. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 405–412, 2003
Amphiphilic styrene–acrylic acid copolymers from the free‐radical retrograde‐precipitation polymerization (FRRPP) process
Authors: Caneba Gerard T. , Zhao Yi , Dar Yadunandan
Published: April 2003

The free‐radical retrograde‐precipitation polymerization (or FRRPP) process, a free‐radical polymerization that occurs above the lower critical solution temperature (LCST), was extended to copolymer formation. Control over the rate of polymerization and entrapment of polymer radicals in the FRRPP process was used to generate tapered styrene–acrylic acid block copolymers. To show the effectiveness of the FRRPP process, the same procedure was used with solvents that are not LCST‐based precipitants for the polymer. Kinetic data show substantial chain termination in non‐FRRPP copolymerization systems. Molecular weight information also shows propagation control in the FRRPP system. Solubilization and emulsification studies also indicate the capability of the FRRPP system in generating a much higher proportion of amphiphilic tapered block copolymers in the solid product. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 426–431, 2003
Applications of polymeric photorefractive material to reversible data storage and information processing
Authors: Chun Hyunaee , Joo Won‐Jae , Kim Nam‐Jun , Moon In Kyu , Kim Nakjoong
Published: April 2003

A polymeric photorefractive composite was prepared from a mixture of carbazole‐substituted polysiloxane as a photoconducting medium, 2,4,7‐trinitro‐9‐fluorenone as a photosensitizer, and 2‐{3‐[(E)‐2‐(dibutylamino)‐1‐ethenyl]‐5,5‐dimethyl‐2‐cyclohexenyliden} malononitrile as an optically nonlinear chromophore. This polymeric composite, with a thickness of 100 μm, exhibited a high diffraction efficiency of 92% at a low applied electric field of 30 V/μm, which corresponded a refractive index modulation of 3 × 10−3. Applications of this polymeric composite to reversible holographic data storage and pattern recognition were demonstrated. The three‐dimensional image was recorded on our photorefractive film at an applied field of 30 V/μm, and subsequently, a high quality image was reconstructed in a real‐time operation. Pattern recognition was successfully demonstrated based on a joint‐transform optical correlation. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 368–372, 2003
Temperature and liquid crystal concentration effect on thermal conductivity of poly(styrene) dispersed 5CB liquid crystal
Authors: Boudenne Abderrahim , Khaldi Smaïn
Published: April 2003

In the present work, we study the thermal behavior of Polymer (Polystyrene) dispersed (4‐cyano‐4′‐pentylbiphenyl) 5CB liquid crystal film composite. A photopyroelectric device was used to study thermal conductivity at homeotropic and planar aligned of 4‐cyano‐4′‐pentylbiphenyl (5CB) liquid crystal. Thermal conductivity of polystyrene (PS) has been determined and calculated from experimental applied data reported in the literature. Thermal conductivity characteristics of the PDLC films were investigated with three prediction models as a function of both temperature and liquid crystal concentration in the polymer matrix. We particularly show the behavior of this thermal conductivity in the ON and OFF state. It was found that the difference in the film thermal conductivity ranges between 3 and 21%, depending on the ON and OFF state and the liquid crystal volume concentration. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 481–486, 2003
Biaxial orientation behavior of polystyrene: Orientation and properties
Authors: Zhang Xiaomin , Ajji Abdellah
Published: April 2003

Square sheets of extrusion grade polystyrene (PS) were biaxially stretched using a laboratory biaxial stretcher. The effects of process parameters such as stretch ratio, drawing sequence, drawing speed, and temperature were studied. Birefringence, mechanical properties, and thermal shrinkage of the stretched sheets were the focus of this study. A high orientation was achieved at high stretch ratio, and orientations from uniaxial to equi‐biaxial were obtained by controlling the relative magnitude of stretch ratio in machine (MD) and transverse (TD) directions. Stretching increased tensile strength and elongation at break significantly, which indicated an improvement in the toughness of the oriented PS sheets. Those properties were correlated with biaxial orientation factors: a rapid increase was observed for both tensile strength and elongation at break for birefringence levels above −0.005, and below, a plateau was observed. The shrinkage strain and stress were found to correlate well with the biaxial orientation factors. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 487–496, 2003
Ink‐eliminated waste paper sludge flour‐filled polypropylene composites with different coupling agent treatments
Authors: Qiao Xiuying , Zhang Yong , Zhang Yinxi , Zhu Yutang
Published: April 2003

Ink‐eliminated sludge flour (IESF), waste residue from the recycling treatments of waste paper, was utilized as a new kind of filler to reinforce polypropylene (PP) in this research work. Different coupling agents, including maleated anhydride grafted PP (MAPP), stearic acid (SA), and titanate (NDZ‐101), were used to increase the compatibility between IESF and PP. By using different measurements, the microstructure, morphology, thermal behaviors, and mechanical properties of the IESF/PP composites were investigated in detail. It was found that IESF, as a nucleation agent, not only induced the crystallization orientation of PP but also accelerate the crystallization rate of PP. Just as indicated in the experiments, the presence of IESF has shown the advantages of increasing the dimensional stability, the hardness and the flexural property, and the presence of coupling agents has a favorable effect on the improvement of dimensional stability. Moreover, the coupling agent has minor influence on the mechanical property, even causes some decrease in the impact strength. Among these three coupling agents, MAPP is found to be the best coupling agent for increasing the interfacial adhesion between IESF and PP, and the MAPP addition makes the PP composite possess the quickest crystallization rate and greatest tensile strength. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 513–520, 2003
Lack of Reelin causes malpositioning of nigral dopaminergic neurons: Evidence from comparison of normal and Relnrl mutant mice
Authors: Nishikawa Shigeyuki , Goto Satoshi , Yamada Kazumichi , Hamasaki Tadashi , Ushio Yukitaka
Published: April 2003

The reeler gene (Relnrl, formerly rl) product Reelin controls neuronal migration and positioning and thereby plays a key role in brain development. Mutation of Reln leads to widespread disruption of laminar cortical regions and ectopia in some brainstem nuclei. In the embryonic striatum of normal mice, a substantial expression of reelin mRNA has been documented; however, the anomalous positioning of neurons in the basal ganglia of reeler mice remains to be studied. We provide first evidence for a potential role of Reelin in the developmental formation of the substantia nigra. In reeler mutant mice lacking Reelin, dopaminergic neurons destined for the substantia nigra fail to migrate laterally and become anomalously clustered just lateral to the ventral tegmental area. Their axons appear to project to striatal patches forming “dopamine islands.” Results from the normal mice show that, at the midembryonic stage, Reelin identified with CR‐50 is highly concentrated in the ventral mesencephalon, where nigral dopaminergic neurons are in progress to migrate laterally to their eventual position of the adult brain. A combination of CR‐50 labeling and anterograde axonal tracing provided evidence that embryonic striatal neurons may supply the ventral portion of the mesencephalon with Reelin through their axonal projections. We hypothesize that Reelin plays a role in the positioning of nigral dopaminergic neurons and that it can act as an environmental cue at a remote site far from its birthplace via a transaxonal delivery system. J. Comp. Neurol. 461:166–173, 2003. © 2003 Wiley‐Liss, Inc.
Central projection of unmyelinated (C) primary afferent fibers from gastrocnemius muscle in the guinea pig
Authors: Ling Li‐Jun , Honda Takashi , Shimada Yasuhiro , Ozaki Noriyuki , Shiraishi Yousuke , Sugiura Yasuo
Published: April 2003

We have demonstrated the central projections of muscle C or group IV afferent fibers in the guinea pig by tracing arborizations in the spinal cord. C afferent fibers from the gastrocnemius muscle (GCM) were electrophysiologically identified by conduction velocity (less than 1 m/second). A single neuron in the lumbar 5 dorsal root ganglion (L5 DRG) was intracellularly labeled with Phaseolus vulgaris leucoagglutinin (PHA‐L). After iontophoretic injection of PHA‐L, we processed the lumbar cord and L5 DRG for PHA‐L immunohistochemistry. Six muscle C afferent fibers from 40 animals were labeled, and whole trajectories were recovered. Labeled fibers were reconstructed by tracing of the arbor in serial parasagittal sections. The GCM C afferents projected rostrocaudally for two or three segments and ran at the surface of the dorsal funiculus, giving off collaterals into laminae I and II and sometimes into parts of lamina III. We determined, based on the branching pattern and form of the terminal plexus, that the branching of muscle C afferent fibers showed an intermediate pattern that fell morphologically between the terminal patterns of somatic and visceral afferents. The numbers and sizes of fiber swellings and terminal swellings were measured on all collateral branches. We found that the area of distribution of the terminal swellings of muscle C afferent fibers is larger than that of somatic terminals but that the density of terminal swellings in the terminal area was lower than that of the somatic terminals. J. Comp. Neurol. 461:140–150, 2003. © 2003 Wiley‐Liss, Inc.
Novel, secondary sensory cell organ in ascidians: In search of the ancestor of the vertebrate lateral line
Authors: Burighel Paolo , Lane Nancy J. , Fabio Gasparini , Stefano Tiozzo , Zaniolo Giovanna , Carnevali Maria Daniela Candia , Manni Lucia
Published: April 2003

A new mechanoreceptor organ, the “coronal organ,” located in the oral siphon, is described by light and electron microscopy in the colonial ascidiansBotryllus schlosseriandBotrylloides violaceus. It is composed of a line of sensory cells (hair cells), accompanied by supporting cells, that runs continuously along the margin of the velum and tentacles of the siphon. These hair cells resemble those of the vertebrate lateral line or, in general, the acoustico‐lateralis system, because they bear a single cilium, located centrally or eccentrically to a hair bundle of numerous stereovilli. In contrast to other sensory cells of ascidians, the coronal hair cells are secondary sensory cells, since they lack axonal processes directed towards the cerebral ganglion. Moreover, at their base they form synapses with nerve fibers, most of which exhibit acetylcholinesterase activity. The absence of axonal extensions was confirmed by experiments with lipophilic dyes. Different kinds of synapses were recognized: usually, each hair cell forms a few afferent synapses with dendrites of neurons located in the ganglion; efferent synapses, both axo‐somatic (between an axon coming from the ganglion and the hair cell) and axo‐dendritic (between an axon coming from the ganglion and an afferent fiber) were occasionally found. The presence of secondary sensory cells in ascidians is discussed in relation to the evolution of sensory cells and placodes in vertebrates. It is proposed that the coronal organ in urochordates is homologous to the vertebrate acoustico‐lateralis system. J. Comp. Neurol. 461:236–249, 2003. © 2003 Wiley‐Liss, Inc.
Patterning of the lateral ganglionic eminence by the Gsh1 and Gsh2 homeobox genes regulates striatal and olfactory bulb histogenesis and the growth of axons through the basal ganglia
Authors: Yun Kyuson , Garel Sonia , Fischman Seth , Rubenstein John L.R.
Published: April 2003

The function of the Gsh1 and Gsh2 homeobox transcription factors during development of the mouse telencephalon was studied using loss of function mutations. No telencephalic phenotype was observed in Gsh1 mutants, whereas Gsh2 and Gsh1/2 mutants showed progressively more severe defects in development of neurons derived from the lateral ganglionic eminence (LGE). These defects arise from abnormal dorsoventral specification of LGE progenitor cells. Mice lacking both Gsh1 and Gsh2 have severe hypoplasia of the striatum, olfactory tubercle, and interneurons that migrate from the dorsal LGE to the olfactory bulb. In addition, Gsh function is linked to the development of telencephalic dopaminergic neurons. These observations show that Gsh1 and Gsh2 have early roles in defining the identity of LGE progenitor cells. As a result of the basal ganglia defects in the Gsh1/2 mutants, there are pallial heterotopia near the cortical/subcortical limit and defects in the pathfinding of corticofugal and thalamocortical fibers. These findings highlight the developmental interdependence of adjacent telencephalic structures. J. Comp. Neurol. 461:151–165, 2003. © 2003 Wiley‐Liss, Inc.