bluuebunny/crossref_metadata_2025 huggingface dataset:
Short Bowel Syndrome
Authors: Wilmore Douglas W. , Robinson Malcolm K.
Published: August 2002

The short bowel syndrome is a symptom complex that occurs in adults who have less than 200 cm of jejunum‐ileum remaining after intestinal resection. Similar symptoms are observed in infants and children following massive bowel resection or congenital anomalies and in individuals with longer segments of intestine with severe mucosal disease. Initial care should focus on a thorough excision of nonviable bowel, an exact measurement of the remaining viable bowel, placing all intestine in continuity at the initial or subsequent operation, and controlling initial food intake. With time, adaptation of the remnant intestine occurs, and absorptive function may be maximized by enhancing the enteral diet and minimizing parenteral nutrition. Growth factors and specialized nutrients may also enhance this process. Intestinal transplantation should be considered in selected individuals with the short bowel syndrome who fail intestinal rehabilitation protocols.
Preoperative Localization of Parathyroid Adenoma in Patients with Concomitant Thyroid Nodular Disease
Authors: Krausz Yodphat , Lebensart Pinchas D. , Klein Martin , Weininger Jolie , Blachar Arye , Chisin Roland , Shiloni Eitan
Published: August 2002

We have previously demonstrated the role of high‐resolution ultrasonography (US) in preoperative localization of parathyroid adenoma in patients with primary hyperparathyroidism (PHPT) and no thyroid abnormalities. The present study prospectively evaluated the possible additional value of 99mTc‐sestamibi (MIBI) in patients with PHPT and concomitant multinodular thyroid disease (MND). Patients with PHPT underwent US and MIBI scintigraphy prior to neck exploration. Imaging data were correlated with the site and pathology of the parathyroid tissue removed and were analyzed separately for patients with MND and those with a normal thyroid gland. Among 77 patients with a solitary parathyroid adenoma at surgery, 40 had concomitant MND, whereas 37 patients had no morphologic changes in the thyroid gland, on US or at surgery. Prior to surgery, MIBI scintigraphy depicted 58 of the 77 adenomas (75%) and US localized 51 (66%); the combined sensitivity was 87% (67/77). Among the 37 patients with no thyroid nodules, MIBI located 29 (78%) and US identified 30 (81%) of the adenomas; the combined sensitivity was 89%. In the 40 patients with MND, MIBI identified 29 adenomas (73%) and US localized only 53% (21/40); the combined sensitivity was 85%. Overall, the positive predictive value (PPV) of MIBI for detecting a solitary parathyroid adenoma was 94%, for US it was 88%, and with the two tests combined it was 97%. In patients with no thyroid abnormalities, the PPV of MIBI and US was 97%, but it decreased to 91% and 78%, respectively, in patients with MND. Two patients with false‐positive findings on both MIBI and US had associated thyroid disease. Hence MIBI scintigraphy contributes to localization of a solitary parathyroid adenoma mainly in patients with concomitant MND. The combined MIBI and US modalities result in sparing these patients bilateral neck exploration.
Peritoneal Echinococcosis
Authors: Karavias Dionissios D. , Vagianos Constantine E. , Kakkos Stavros K. , Panagopoulos Constantine M. , Androulakis John A.
Published: August 2002

Peritoneal echinococcosis is rare, even in areas where hydatid disease is endemic. Although the liver and lungs are the organs most commonly involved, peritoneal echinococcosis, either primary or secondary, represents an uncommon but significant manifestation of the disease. We reviewed the medical records of 121 patients with abdominal echinococcosis operated on in our department over the past 12 years. Peritoneal echinococcosis was found in 17 patients, usually combined with liver disease. The presenting symptoms were mostly atypical, and a few cases were discovered accidentally during routine follow‐up after operations for hepatic echinococcosis. Surgery remains the best curative or palliative treatment for peritoneal echinococcosis, although anthelmintics can be an effective alternative for the treatment of small and asymptomatic cysts.
De Novo Hepatitis B and C Viral Infection after Liver Transplantation
Authors: Cavallari Antonino , De Raffele Emilio , Bellusci Roberto , Miniero Rita , Vivarelli Marco , Galli Silvia , Luchetti Rita , Fruet Fiorenza , Giordano Emanuele , Mazziotti Alighiero , Conte Roberto , Sprovieri Giuseppe
Published: August 2002

Hepatitis B (HBV) and hepatitis C (HCV) viral infections often recur after orthotopic liver transplantation (OLT), but viral infections acquired with OLT have not been widely investigated. The aim of the study was to evaluate the incidence, evolution, and diagnostic problems of de novo HBV and HCV infections in liver transplant recipients with long‐term follow‐up. Altogether 121 transplant recipients entered the study. HBV, HDV, and HCV infections were diagnosed by means of serology and the polymerase chain reaction (PCR). Three patients became hepatitis B surface antigen (HBsAg)‐positive after OLT, all of whom showed signs of persistent viral replication. Twelve patients became anti‐HCV‐positive after OLT: After clearance of passive antibodies, active anti‐HCV seroconversion was usually delayed. The viral genome was detected in 9 of 12 patients, with fluctuations of viremia during their follow‐up. The other three patients, who were HBsAg‐positive before and after OLT, were repeatedly HCV‐RNA‐negative despite persistent anti‐HCV reactivity. Four pre‐OLT HBsAg‐positive patients had evidence of HBV‐related liver transplant disease. The remaining 8 of 12 patients experienced repeated alanine aminotransferase increases more than two times normal after transplant. De novo infections due to primary hepatotropic viruses were frequent after OLT in our experience. Early diagnosis of infection, especially when the HCV is involved, may be problematic and should be taken into account in patients showing persistent aminotransferase abnormalities. Monitoring viral markers and accurate evaluation of biopsy specimens are mandatory. The interference between HBV and HCV might play a role in the replicative cycle of one or both viruses in co‐infected patients.
Historical evolution of inguinal hernia repair
Authors: Sachs M. , Damm M. , Encke A.
Published: August 2002

When analyzing original articles since the sixteenth century, it becomes apparent that all surgical techniques for repair of the inguinal hernial orifice can be traced back to two simple repair principles. The first is reinforcement of the anterior wall of the inguinal canal and tightening of the external inguinal ring (Stromayr 1559, Purmann 1694, Czerny 1877), and the second is reinforcement of the posterior wall of the inguinal canal and the tightening of the internal inguinal ring, either externally (Lucas‐Championnière 1881, Bassini 1889, Lotheissen 1898, McVay 1942, Shouldice 1945, Lichtenstein 1987, Stoppa 1989) or via an intraabdominal approach by laparotomy (Tait 1891) or laparoscopically (Ger 1990, Velez and Klein 1990). We have tried to provide a systematic order to the diverse procedures of surgery of inguinal hernias according to their repair principles. We also point out their historical development.
Incidence of Acute Nonperforated and Perforated Appendicitis: Age‐specific and Sex‐specific Analysis
Authors: Körner Hartwig , Söndenaa Karl , Söreide Jon Arne , Andersen Egil , Nysted Arne , Lende Tone H. , Kjellevold Kjell H.
Published: August 2002

This prospective study was performed to investigate epidemiological characteristics in terms of the age‐ and sex‐specific incidence in patients with perforated and nonperforated appendicitis. The study population comprised 1486 consecutive patients who underwent appendectomy for suspected acute appendicitis between 1989 and 1993. Two patient cohorts [n= 544 (37%)] were analyzed with regard to prehospitalization duration of symptoms and in‐hospital observation time. The crude incidence of acute appendicitis was 86 per 100,000 per year. Although the incidence of nonperforated appendicitis was highest among adolescents and young adults (13–40 years of age), perforated appendicitis occurred at almost the same incidence in all sex and age groups. The diagnostic accuracy was 76%. Perforated appendicitis occurred in 19%, with higher rates in small children and the elderly, irrespective of gender. A high diagnostic accuracy was not associated with an increased rate of perforation. In small children and the elderly, the diagnostic accuracy was low and the perforation rate high. Patients with perforation had a significantly longer duration of symptoms as well as in‐hospital observation time than did patients with nonperforated appendicitis. Perforated appendicitis showed a different incidence pattern than nonperforated appendicitis and was associated with a significantly longer duration of symptoms and in‐hospital observation time, probably due to patient‐related factors. We suggest this observation deserves attention regarding clinical diagnosis and treatment decision‐making for patients with suspected acute appendicitis.
Abdominoperineal Resection via Total Mesorectal Excision and Autonomic Nerve Preservation for Low Rectal Cancer
Authors: Enker Warren E. , Havenga Klaas , Polyak Tatyana , Thaler Howard , Cranor Millicent
Published: August 2002

We have examined the results of abdominoperineal resection (APR) for primary cancer of the rectum performed in accordance with the principles of total mesorectal excision (TME) and autonomic nerve preservation (ANP). TME is defined as sharp pelvic dissection under direct vision between the parietal and visceral planes of the pelvic fascia. TME results in the resection of all mesorectal disease with intact, negative lateral or circumferential margins of resection. Statistical analysis was done of survival, local recurrence, and both sexual and urinary functions in a prospective database of consecutive patients. Operative mortality was
2% (3/148) due to cardiac disease. Overall survival was 60%, significantly worse than consecutive patients from the same database who were able to undergo sphincter preservation (81%)
(p= 0.0003). Poorer survival was statistically related to the presence of positive lymph nodes (p=
0.0009). Overall, local recurrence rates were 5% (8/148) in patients without distant metastases, and 15% to 21% in patients with positive nodes. Positive lymph nodes, N2 disease, lymphatic vascular invasion, and perineural invasion were independent significant risk factors for local recurrence. Sexual function was preserved in approximately 57% of patients undergoing APR versus 85% of patients undergoing sphincter preservation. No significant urinary morbidity was encountered. Low rectal cancer requiring APR seems to be a disease with more locally advanced disease and adverse pathologic features than are seen with mid‐rectal cancers treatable by low anterior resection. APR when performed in accordance with the principles of TME and ANP ensures the greatest likelihood of resecting all regional disease while preserving both sexual and urinary functions. Preoperative combined modality treatment may be warranted in all T3 or greater low rectal cancers.
Impact on Outcome of Additional Microvascular Anastomosis—Supercharge—on Colon Interposition for Esophageal Replacement: Comparative and Multivariate Analysis
Authors: Fujita Hiromasa , Yamana Hideaki , Sueyoshi Susumu , Shima Ichiro , Fujii Teruhiko , Shirouzu Kazuo , Inoue Yojiro , Kiyokawa Kensuke , Tanabe Hiroko Yanaga , Tai Yosiaki , Inutsuka Hiroki
Published: August 2002

The impact on the outcome of an additional microvascular anastomosis—supercharge—on colon interposition for esophageal replacement was retrospectively evaluated by comparing it with colon interposition without supercharge. A series of 53 patients had undergone colon interposition for esophageal replacement at Kurume University Hospital from 1981 to 1996. The postoperative courses and the morbidity and mortality rates were compared between the 24 patients who underwent colon interposition without supercharge from 1981 to 1988 and the other 29 patients who underwent colon interposition with supercharge from 1989 to 1996. Risk factors for leakage of the esophagocolostomy and for hospital mortality after colon interposition were evaluated by multivariate analysis. Colon interposition with supercharge required a longer operation time but resulted in a lower incidence of necrosis in the colon graft and leakage in the esophagocolostomy (Odds ratio = 34), a shorter duration until peroral intake, and a shorter hospital stay compared to colonic interposition without supercharge. The addition of supercharge to colon interposition for esophageal replacement has been an effective option that has prevented serious complications caused by graft ischemia.
Female Genital Mutilation: A Global Bug That Should Not Cross the Millennium Bridge
Authors: Eke Ndu , Nkanginieme Kanu E.O.
Published: August 2002

Female genital mutilation (FGM) has been practiced worldwide, clothed under the tradocultural term “circumcision.” Indications for its practice include ensuring virginity, securing fertility, securing the economic and social future of daughters, preventing the clitoris from growing long like the penis, and purely as a “tradition.” Outlawed only in the United Kingdom, Sweden, and Belgium, no law forbids it in most other countries. Classified into four identified types, the current perpetrators are mainly quacks, but trained medical personnel still connive at and encourage FGM. Early complications include hemorrhage, urinary tract infection, septicemia, and tetanus. Late complications include infertility, apareunia, clitoral neuromas, and vesicovaginal fistula. Reasons for the ritual persisting include fear that legislation would force it underground and it will be performed in unsterile conditions, belief that it is racist to speak out against FGM, “tolerance” by health professionals, continued use of the term “female circumcision,” lack of awareness of the culture of immigrants by the physicians in areas where FGM is not culturally practiced, and sporadic or uncommitted eradication efforts. We believe there is no reason for the continued practice of FGM. It should incur global abolition, the same way slave trade or Victorian chastity belts have done. We advocate that in medical communications the term “female genital mutilation” be used in place of “female circumcision.” World leaders should include unacceptable cultural practices such as FGM in the “world summit” agenda. The year 1999 should be declared the year for global eradication of FGM.
Active female courtship behavior and male nutritional contribution to female fecundity in Bruchidius dorsalis (Fahraeus) (Coleoptera: Bruchidae)
Authors: Takakura Koh‐ichi
Published: August 2002

Mating behavior and the male's contribution to female fecundity were studied in the bean weevil Bruchidius dorsalis (Fahraeus) (Coleoptera: Bruchidae) in comparison with two other species, Callosobruchus chinensis (which infests stored beans) and Kytorhinus sharpianus (which feeds on wild legumes). Only females of B. dorsalis showed multiple mating and characteristic precopulatory behavior that appeared to solicit the male's nutritious secretion. In contrast, all females of the other two species did not copulate multiply and did not show such precopulatory behavior. In B. dorsalis, the decrement of male body weight just after copulation indicated that seminal fluid weighing as much as approximately 7% of the male's body weight was transferred to the female. Fecundity was more than eight times higher in females that had copulated ten times than in females that had copulated only once, indicating that males paid most of the nutritional cost of egg production. These facts suggest that the sex role is reversed in B. dorsalis.
Pediatric Oncology Nursing: Providing Care through Decades of Change
Authors: Forte Kathy
Published: August 2002

Pediatric oncology nursing practice has evolved over the years as new technology and trends in health care have precipitated change. Three pediatric oncology nursing leaders share their perspectives on nursing practice as it relates to treatment of a child with leukemia during four different points in time. Their comments illustrate the challenges, resources, and rewards. Their reflections, combined with a survey of the literature over the past half a century, show the dramatic impact of advances in supportive care on the practice of caring for a child with cancer. It is also evident that as the cure rate has increased, so have the efforts to improve quality of life. What has transcended time is the delivery of consistent and compassionate care, the education of patients and families, and the dedication to advocacy and support.
From Single Site to Societal Belief: The Impact of Pediatric Oncology Nursing Research
Authors: Schneider Susan M. , Hinds Pamela S. , Pritchard Michele
Published: August 2002

This review describes the evolution of pediatric oncology nursing research over the past 25 years. It highlights practice-changing contributions from single-site studies and from multisite trials and discusses strategies for interdisciplinary collaboration. Technological advances that will alter the way in which studies are conducted and findings are disseminated will influence the future of nursing research. Studies implemented by pediatric nurse researchers will continue to influence practice and change how we, and others, view the experience of childhood cancer.
Repair of Urinary Bladder Rupture Through a Urethrotomy and Urethral Sphincterotomy in Four Postpartum Mares
Authors: Higuchi Tohru , Nanao Yuki , Senba Hiroyuki
Published: August 2002

Objective—To report the clinical findings, surgical technique, and outcome after repair of urinary bladder rupture through a urethral incision in postpartum mares.

Study design—Retrospective study.

Animals—Four Thoroughbred broodmares.

Methods—Medical records were reviewed for clinical signs, surgical technique, medical therapy, and outcome. The bladder was everted into the vagina through a urethral incision that included a sphincterotomy. The bladder defect was repaired with absorbable suture material in a single‐layer, full thickness, simple, continuous pattern. The urethral incision was closed similarly.

Results—Depression, inappetence, signs of shock, dehydration, azotemia, and serum electrolyte abnormalities were consistent findings that increased temporally after bladder rupture. Each bladder defect was repaired successfully, and metabolic derangements were corrected with supportive medical therapy. All mares survived, conceived, and had more foals without further complications

Conclusion and clinical relevance—Bladder rupture associated with parturition in mares can be repaired in a standing position by eversion of the bladder through a urethrotomy and urethral sphincterotomy.
Controlling chaos through growth rate adjustment
Authors: Huang Weihong
Published: August 2002

An extremely fast growth‐rate controlling mechanism has been developed to stabilize a discrete system. Theoretical analysis and computer simulations have been provided to show the effectiveness and efficiency of this new mechanism in practice.
Porphyrin analogues
Authors: SESSLER JONATHAN L.
Published: August 2002

The chemistry of porphyrin analogues, fully or partially conjugated macrocyclic systems that contain pyrroles but are not naturally occurring substances, is discussed from an historic perspective. Key developments that led to the emergence of this area as a separate discipline within the generalized porphyrin lexicon are highlighted with a view to allowing the reader to understand better the current state of the art in the field.
Rapid chromosome detection by PRINS in human sperm
Authors: Pellestor Franck , Imbert Isabelle , Andréo Brigitte
Published: August 2002

Primed in situ (PRINS) labeling may be used for direct estimation of disomy rate in human sperm. We combined the PRINS procedure with a rapid and efficient NaOH pretreatment allowing simultaneous decondensation and denaturation of sperm nuclei. This enabled double labeling of human sperm within a 2‐hr time span. Chromosome‐specific primers have been defined for most human chromosomes, including those most frequently involved in aneuploidy. Using the dual‐color PRINS method, we estimated incidences of disomy for 15 autosomes and the sex chromosomes in sperm samples from 6 normal fertile men. The frequency of disomy ranged from 0.28% to 0.36%. There were no significant interchromosomal differences in disomy rate, but chromosome 21 displayed a higher incidence of nondisjunction than did the other chromosomes. © 2001 Wiley‐Liss, Inc.
Application of CO2 laser heating zone drawing and zone annealing to nylon 6 fibers
Authors: Suzuki Akihiro , Ishihara Masayoshi
Published: August 2002

Nlon 6 fibers were zone drawn and zone annealed by using a continuous wave carbon dioxide laser to develop their mechanical properties. A laser‐heating zone drawing was carried out under a applied tension of 35.4 MPa at a power density of 9.65 W · cm−2, and then the zone‐drawn fiber was annealed. A laser‐heating zone annealing was carried out in two steps at a power density of 9.65 W · cm−2; the first step was carried out under 423 MPa and the second under 517 MPa. The treating temperature of the fiber heated by the CO2 laser was measured by using an infrared thermographic camera equipped with a magnifying lens. The treating temperature at the zone drawing is 138°C, and those at the first and the second zone annealing are 121 and 125°C, respectively. The second laser‐heated zone‐annealed fiber has a birefringence of 65.2 × 10−3, a degree of crystallinity of 54%, and a storage modulus of 21 GPa at 25°C. Wide‐angle X‐ray diffraction patterns for the laser‐heated zone‐drawn and the zone‐annealed fibers show (200) reflection and (002/202) doublet due to only an α form on the equator. The laser‐heated zone‐drawn fiber has a melting endotherm peaking at 216°C and a trace of shoulder on the higher temperature side of its peak, and the laser‐heated zone‐annealed fibers have a single melting endotherm peaking at 216°C. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1711–1716, 2002
Melting and crystallization behavior of aliphatic polyketones
Authors: Holt Jr. G. A. , Spruiell J. E.
Published: August 2002

The basic crystallization and melting behavior of three aliphatic polyketones were studied using differential scanning calorimetry (DSC), wide‐angle X‐ray diffraction (WAXD), small‐angle X‐ray scattering (SAXS), and optical microscopy. One resin was a perfectly alternating copolymer of ethylene and carbon monoxide, while the other two resins were terpolymers in which 6 mol % propylene was substituted for ethylene. Small decreases in the melting point and percent crystallinity of these materials were displayed with repeated melting. This behavior was attributed to light crosslinking as a result of condensation reactions occurring at temperatures in the melting range. WAXS showed that, after cooling to room temperature, the crystalline form in the copolymer was the α‐phase, while that in the terpolymers was the β‐phase. Optical microscopy revealed that the materials produce both negative and mixed birefringence spherulites under the conditions studied. SAXS measurements showed that the lamella thickness was largely a function of the temperature of crystallization. Attempts were made to measure the equilibrium melting temperature of these resins using several available techniques. The best value of the equilibrium melting temperature was concluded to be 278 ± 2°C for the copolymer. The results varied over a wide range for the terpolymers, but it is suggested that appropriate values are of order 252°C for the terpolymers. Crystallization kinetics studies, carried out under isothermal conditions using DSC, were evaluated using the Avrami equation. Results showed the Avrami exponent to lie in the range of 2–3. Spherulite growth rates were interpreted in terms of the secondary nucleation theory of Lauritzen and Hoffman. A transition from regime II to regime III was discovered. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2124–2142, 2002
Characterization and preparation of polyion complex composite membranes for the separation of methyl tert‐butyl ether/methanol mixtures
Authors: Kim Sang‐Gyun , Kim Yong‐Il , Jegal Jonggeon , Lim Gyun‐Taek , Lee Kew‐Ho
Published: August 2002

A series of polyion complex (PIC) composite membranes composed of sodium alginate (SA) polyanion and chitosan polycation were prepared by varying the ratio of concentration. The interaction between SA and chitosan was investigated by FTIR, SEM, and X‐ray analysis and was related to mechanical properties and the swelling phenomenon. The overall PIC composite membranes showed the following results: the total thickness of the coating layer was thicker than that of pure SA composite, and increased with increasing the concentration of chitosan solution during PIC formation. This result was attributed to the diffusion of chitosan molecules from the liquid solution into the SA matrix, and the incorporation with SA molecules. For the PIC membranes prepared with different concentrations of polymer solution, their structural differences could not be detected from IR spectra but their morphological differences could be noticeably found from SEM. Furthermore, the amorphousness of PIC membranes and their elongation properties at break increased significantly as a function of polymer contents, whereas the tensile modulus decreased because of the physical transition effect. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 714–725, 2002
Effects of extrusion conditions on rheological behavior of acrylonitrile–butadiene–styrene terpolymer melt
Authors: Liang Ji‐Zhao
Published: August 2002

The influence of temperatures and flow rates on the rheological behavior during extrusion of acrylonitrile–butadiene–styrene (ABS) terpolymer melt was investigated by using a Rosand capillary rheometer. It was found that the wall shear stress (τw) increased nonlinearly with increasing apparent shear rates and the slope of the curves changed suddenly at a shear rate of about 103 s−1, whereas the melt‐shear viscosity decreased quickly at a τw of about 200 kPa. When the temperature was fixed, the entry‐pressure drop and extensional stress increased nonlinearly with increasing τw, whereas it decreased with a rise of temperature at a constant level of τw. The relationship between the melt‐shear viscosity and temperature was consistent with an Arrhenius expression. The results showed that the effects of extrusion operation conditions on the rheological behavior of the ABS resin melt were significant and were attributable to the change of morphology of the rubber phase over a wide range of shear rates. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 606–611, 2002
Differences in curing behavior of cocured and IPN materials
Authors: Lin Mu‐Shih , Chiu Chun‐Chen
Published: August 2002

This study addressed the blending and cocuring of resole and epoxy, using NaOH and 4,4′‐diaminodiphenylmethane as curing agents. IR band shifts regarding the molecular interactions were investigated with FTIR. Exothermic peak shifts during cocuring reactions were studied with dynamic DSC. Viscosity increases were measured with a Brookfield LVT viscometer at 100°C. The dynamic mechanical properties of the cocured samples were investigated using rheometric dynamic spectroscopy (RDS). Experimental results revealed that the molecular interactions between resole and epoxy resulted in good compatibility as shown by the single damping peak in the RDS curve and the single glass transition for each cocured sample. Also apparent were accelerated curing rates, leading to shifts of the exothermic peaks to lower temperature and faster viscosity increases. Nevertheless, enhanced gel fractions and increased glass‐transition temperatures (Tg) of the samples were generally observed for this cocured system. The average molecular weight between crosslinked points calculated for the cocured materials also showed much less than the two components. These curing behaviors were quite different from those of the Interpenetrating Polymer Network (IPN) materials, which usually indicated lowered gel fractions, decreasedTg, and higher average molecular weight between crosslinkings than for components. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 963–969, 2001
Continuous emulsion polymerization of styrene in a single Couette–Taylor vortex flow reactor
Authors: Wei Xue , Takahashi Hiroshi , Sato Syuzaemon , Nomura Mamoru
Published: August 2002

The effect of the geometrical and operational parameters on the mixing characteristics of a Couette–Taylor vortex flow reactor (CTVFR) were investigated and were correlated with the same parameters by using the tank‐in‐series model. Continuous emulsion polymerization of styrene was conducted at 50°C in a CTVFR to clarify the effects on kinetic behavior and reactor performance of operational parameters such as rotational speed of inner cylinder (Taylor number), reactor mean residence time, and emulsifier and initiator concentrations in the feed streams. It was found that steady‐state monomer conversion and particle number could be freely varied only by varying the Taylor number. In order to explain the observed kinetic behavior of this polymerization system, a mathematical model was developed by combining the empirical correlation of the mixing characteristics of a CTVFR and a previously proposed kinetic model for the continuous emulsion polymerization of styrene in continuous stirred tank reactors connected in series (CSTRs). On the basis of these experimental results, it was concluded that a CTVFR is suitable for the first reactor (prereactor) of a continuous emulsion polymerization reactor system. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1931–1942, 2001
Thermal redistribution reactions of Blackglas™ ceramic
Authors: Wang Feng , Apple Tom , Gill William N.
Published: August 2002

Silicon oxycarbides undergo SiO and SiC bond redistribution when heated in an inert atmosphere above 900°C. This redistribution has a great influence on the mechanical, thermal, and oxidative stability properties of Blackglas™ ceramic. Based on a statistical method, three independent thermal redistribution reactions were chosen to describe the redistribution reactions between 900 and 1350°C. Over this temperature range, only SiO and SiC bond redistribution is involved, and the char yield is constant. The equilibrium constants of each independent reaction and their temperature dependence are calculated directly by using 29Si‐NMR experimental data for temperatures of 900, 1000, and 1100°C and fitted to a cubic polynomial. A redistribution reaction model (RRM) is proposed to describe how the microcompositions of silicon oxycarbide change with respect to temperature. The model is based on 29Si‐NMR data from 900 to 1100°C. It enables one to extrapolate results to 1400°C and indicates that the silicon oxycarbide can survive above 1400°C and that the microcomposition is very sensitive to the ratio O/Si in the polymer precursor. This prediction is in a good agreement with the experimental results observed by Belot et al., Corriu et al., Bois et al., and F. Babonneau et al. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 143–152, 2001
Effect of ions on the dynamic behavior of an electrodriven ionic polymer hydrogel membrane
Authors: Homma M. , Seida Y. , Nakano Y.
Published: August 2002

The bending mechanism of an electrodriven ionic polymer hydrogel membrane was investigated in terms of the concentration of ionic groups and the valence of ionic species within the hydrogel membrane. It was elucidated that the distribution of the ionic concentration played an important role in the bending behavior of the membrane. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 76–80, 2001
Some aspects of the properties of nylon‐6, 6/poly(ethylene naphthalate) blends
Authors: Jung Dylan D. , Bhattacharyya Debes , Easteal Allan J.
Published: August 2002

Blends of Nylon 66(Ny66) and polyethylene naphthalate (PEN) with 30, 50, 70 wt % Ny66, and one blend with 50% Ny66 and 3% compatibilizer, prepared by extrusion and injection molding, were investigated using 13C and 1H nuclear magnetic resonance (NMR), Fourier transform infrared spectroscopy (FTIR), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). A new band in the FTIR spectra of blends, at 1324–1329 cm−1 is interpreted as arising from partial reaction of Ny66 and PEN occurring during melt processing. However, NMR spectra show no evidence of interchange reaction between Ny66 and PEN. SEM indicates that the phase inversion point is close to equal proportions by weight of the two homopolymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1504–1514, 2001
Development of membranes by radiation grafting of acrylamide into polyethylene films: Characterization and thermal investigations
Authors: Gupta Bhuvanesh , Anjum Nishat
Published: August 2002

Polyethylene‐g‐polyacrylamide membranes were prepared by graft polymerization of acrylamide into polyethylene films by preirradiation technique. The characterization and thermal behavior of membranes with different degrees of grafting were evaluated by density, X‐ray diffraction, thermogravimetric analysis, and differential scanning calorimetry measurements. Grafting led to considerable changes in the structure of polyethylene membranes. The density of the polyethylene film increased wtih the increase in the degree of grafting, although the increase beyond 100% grafting was less pronounced than at lower graft levels. The heat of fusion and the crystallinity of polyethylene decreased with the increase in the degree of grafting. The decrease in crystallinity is because of the cumulative effect of the dilution of inherent crystallinity by the incorporation of amorphous polyacrylamide grafts within the noncrystalline region of polyethylene (dilution effect) and partial disruption of the crystallites (crystal defects). X‐ray diffraction measurements also revealed a decrease in the crystallinity in grafted films. Membranes behaved as a two‐component system where polyethylene and polyacrylamide components underwent independent degradation irrespective of the graft levels. In general, the thermal stability of polyethylene in membranes was markedly improved by the grafting of acrylamide monomer as evident from the initial decomposition temperature increasing from 311°C for virgin PE to 390°C in grafted membranes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2629–2635, 2001
A new analytical method to calculate intrinsic viscosity and viscosity constants of polymer–solvent systems
Authors: Toti Udaya S. , Amur Krishna S. , Kariduraganavar Mahadevappa Y. , Manjeshwar Lata S. , Aralaguppi Mrityunjaya I. , Aminabhavi Tejraj M.
Published: August 2002

Experimental viscosities were measured by Schott Gerate viscometer at 30 °C for polystyrene–chloroform and polycaprolactum–benzene systems. These data were analyzed by a newly developed analytical method to calculate intrinsic viscosity and viscosity constants. The analytical method was compared with the graphical as well as the least squares methods and the new analytical method is better than the graphical method because it avoids personal errors that might arise in reading the intercept and slope values from the reduced viscosity versus concentration plots. Furthermore, the analytical method is as effective as the least squares method, but provides better insights while choosing the experimental viscosity values. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 283–290, 2002
Synthesis of graft copolymers from natural rubber using cumene hydroperoxide redox initiator
Authors: Arayapranee W. , Prasassarakich P. , Rempel G. L.
Published: August 2002

The graft copolymerization of 50/50 (w/w) styrene/methyl methacrylate mixtures onto natural rubber seed latex were carried out by using cumene hydroperoxide/sodium formaldehyde sulfoxylate dihydrate/EDTA‐chelated Fe2+ as a redox initiator. The effects of the process factors such as the amount of initiator, emulsifier, and chain‐transfer agent; monomer‐to‐rubber ratio; and temperature on the grafting efficiency (GE) and grafting level (GL) are reported. The mechanism of graft copolymerization was investigated. The synthesized graft copolymers were purified and then characterized by proton nuclear magnetic resonance (1H‐NMR) analysis. Transmission electron microscopy (TEM) was used to study the morphology of the graft copolymers. It appears that the formation of graft copolymers occurs on the surface of the latex particles through a chain‐transfer process. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2993–3001, 2002; DOI 10.1002/app.2328
An application of three bivariate time‐varying volatility models
Authors: Vrontos I. D. , Giakoumatos S. G. , Dellaportas P. , Politis D. N.
Published: August 2002

The multivariate time‐varying volatility models have recently attracted a lot of attention in the statistics/econometrics community. We apply two bivariate ARCH–GARCH models and a bivariate unobserved ARCH model to a series of exchange rates, and we estimate the parameters using Bayesian inference. We compare these models using a posterior predictive model diagnostic. Copyright © 2001 John Wiley & Sons, Ltd.
New Fourier transform infrared based computational method for peptide secondary structure determination. II. Application to study of peptide fragments reproducing processing site of ocytocin–neurophysin precursor
Authors: Simonetti Mario , Di Bello Carlo
Published: August 2002

A new method for the quantitative determination of the percentage of intramolecular H‐bonds, based on Fourier transform infrared techniques, is applied to the conformational analysis of a series of synthetic peptides spanning the processing site of the ocytocin and neurophysin precursor. Even though the method uses traditional tools such as Fourier self‐deconvolution, the Nth derivative, and curve‐fitting procedures for the analysis of the spectra, the assignment of the absorptions due to peptide groups participating into secondary structures is based on the direct observation and quantification of the isotopic effect induced on the groups participating in intramolecular H‐bonds in the presence of organic solvents. This permits the quantification of the different populations of molecules containing intramolecular H‐bonds involved in β‐turns and α‐helices. The results are consistent with those previously obtained by NMR techniques in the same solvent systems. © 2001 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 62: 109–121, 2001
Type‐specific separation of animal cells in aqueous two‐phase systems using antibody conjugates with temperature‐sensitive polymers
Authors: Kumar A. , Kamihira M. , Galaev I. Yu. , Mattiasson B. , Iijima S.
Published: August 2002

A new type of aqueous two‐phase system (ATPS) has been developed in which a temperature‐sensitive polymer, poly‐N‐isopropylacrylamide [poly (NIPAM)] was used as a ligand carrier for the specific separation of animal cells. Monoclonal antibodies were modified with itaconic anhydride and copolymerized with N‐isopropylacrylamide, and the ligand‐conjugated carriers were added to the polyethylene glycol 8000–dextran T500 aqueous two‐phase systems. The antibody–polymer conjugates were partitioned to the top phase in the absence or presence of 0.15 M NaCl. When ligand‐conjugated carriers were used, more than 80% of the cells were specifically partitioned to the top phase in the presence of NaCl up to 0.1 M. The cells were partitioned almost completely to the bottom phase at 0.1 M NaCl or above, when no antibody–conjugate was added in the ATPS. As a model system, CD34‐positive human acute myeloid leukemia cells (KG‐1) were specifically separated from human T lymphoma cells (Jurkat) by applying anti‐CD34 conjugated with poly‐N‐isopropylacrylamide in the aqueous two‐phase system. By the temperature‐induced precipitation of the polymer, about 90% of the antibody–polymer conjugates were recovered from the top phase, which gave approximately 75% cell separating efficiency in the next cycle of reuse. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 570–580, 2001.
Enzymatic hydrolysis of nitrides by an engineered nitrile hydratase (Papain Gln19Glu) in aqueous‐organic media
Authors: Versari Andrea , Ménard Robert , Lortie Robert
Published: August 2002

A mutant of the cysteine protease papain, displaying nitrile hydratase and amidase activities, was expressed in Pichia pastoris and used for the hydrolysis of peptide nitriles in aqueous‐organic media. The rate of hydrolysis of these nitriles is lowered by increasing acetone concentration. This is caused by an increase of the Michaelis constant, and a variation of Vmax proportional to the amount of water in the mixture. The hydrolysis of the amide is less affected by the increase in co‐solvent, which results in lower accumulation of this intermediate product. With the peptide nitrile tested, high nitrile concentrations could be used to promote the production of the amide and prevent its hydrolysis to the acid by diminishing the relative rate of amide hydrolysis. A number of non‐peptidyl nitriles were also tested as potential substrates but activity was detected for only one compound with structural resemblance to peptide nitriles. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 9–14, 2002.
The meaning of malingering data: further applications of Bayes' theorem
Authors: Mossman Douglas
Published: August 2002

A previous Behavioral Sciences and the Law article (Mossman & Hart, 1996) asserted that information from malingering tests is best conceptualized using Bayes' theorem, and that courts therefore deserve Bayesian interpretations when mental health professionals present evidence about malingering. Mossman and Hart gave several examples of estimated Bayesian posterior probabilities, but they did not systematically address how one constructs confidence intervals for these estimates. This article explains how the usually imperfect nature of humanly created diagnostic tests mandates Bayesian interpretations of test results, and describes methods for generating confidence intervals for posterior probabilities. Sample calculations show that Bayesian reasoning is quite feasible and would not require investigators to expend unusual efforts when constructing and validating malingering instruments. Bayesian interpretations most accurately capture what malingering tests do: provide information that alters one's beliefs about the likelihood of malingering. Copyright © 2000 John Wiley & Sons, Ltd.
Sources and Information: Creating Effective Collaboration Between High Schools and Community Colleges
Authors: Gomez Gigi G.
Published: August 2002

This annotated bibliography presents exemplary concurrent enrollment programs, discusses controversies about student outcomes, and recommends steps for establishing partnerships with local schools.
The role of leadership in successful vocational initiatives
Authors: Summers Michael D.
Published: August 2002

Vocational education is occurring in an environment of new technologies, global competition, and changing demographics that is transforming community colleges. Leaders with foresight and courage will have a positive influence on their institutions and promote the new vocationalism.
Two‐Year colleges and tech prep partnerships: A Texas perspective
Authors: Brown Carrie H.
Published: August 2002

This chapter focuses on the involvement of two‐year colleges in tech prep within multiple workforce development partnerships particular to the unique geography of Texas. Results of a survey of Texas technical education administrators offer insights into how tech prep is perceived to have an impact on postsecondary technical programs.
Learner‐centered instructional practices supporting the new vocationalism
Authors: Dare Donna E.
Published: August 2002

Instructional priorities have shifted to accommodate new categories of learners and acknowledge students' multiple intelligences. Constructivist curriculum theories have been employed to meet learners' needs in vocational programs.
The state of welfare reform in the rural communities of Illinois
Authors: Pampe Kathleen Vespa
Published: August 2002

This chapter discusses community colleges and welfare to work from a rural perspective, specifically in Illinois. It examines the barriers to rural welfare recipients in terms of job placement, the benefits of collaborative efforts and partnerships, and the importance of education and training.
The JOBSplus! program: Successful work first through a family‐based approach
Authors: Higgins Patricia C. , Mayne Janice , Deacon Patricia , LaComb Elena
Published: August 2002

This chapter presents the story of a successful welfare reform program and explains how one upstate New York county and community college created a unique and comprehensive methodology.
Transcatheter closure of a 16 mm hypertensive patent ductus arteriosus with the Amplatzer muscular VSD occluder
Authors: Demkow Marcin , Ruzyllo Witold , Siudalska Hanna , Kepka Cezary
Published: August 2002

There is little experience with transcatheter closure of very large, hypertensive patent ductus arteriosus. We present a case of successful closure of a 16 mm ductus with the Amplatzer VSD occluder, a device originally designed for transcatheter closure of congenital muscular ventricular septal defects. To our best knowledge this is the largest ductus ever closed by an interventional technique. Cathet Cardiovasc Intervent 2001;52:359–362. © 2001 Wiley‐Liss, Inc.
Chiral HPLC separation and CD spectra of the enantiomers of the alkaloid tacamonine and related compounds
Authors: Caccamese Salvatore , Principato Grazia , Jokela Reija , Tolvanen Arto , Din Belle David
Published: August 2002

The HPLC enantiomeric separation of racemic indole alkaloids tacamonine, 17α‐hydroxytacamonine, deethyleburnamonine, and vindeburnol was accomplished using Chiralpak AD and Chiralcel OD as chiral stationary phases. Small structural differences affect the enantioselectivity ability of these phases. Single enantiomers of tacamonine and vindeburnol were isolated by semipreparative HPLC and their CD spectra and optical rotations were measured. Chirality 13:691–693, 2001. © 2001 Wiley‐Liss, Inc.