bluuebunny/crossref_metadata_2025 huggingface dataset:
Canine Gallbladder Infarction: 12 Cases (1993–2003)
Authors: Holt D. E. , Mehler S. , Mayhew P. D. , Hendrick M. J.
Published: July 2004

A cohort of 12 dogs with severe transmural gallbladder necrosis is described. All dogs had cholecystectomies performed. In six dogs, perforation of the gallbladder was noted at surgery. Eight dogs survived the immediate postoperative period, and four dogs died. Histologically, inflammation was absent or minimal in all cases, suggesting that cholecystitis was not the cause of necrosis. Thrombi ( n = 2) and atheromatous vascular changes ( n = 1) represent possible vascular causes of this condition. The findings of coagulative necrosis in these 12 dogs are compatible with “gallbladder infarction,” and the authors propose this term to describe the histopathologic appearance of the gallbladder.
Expression of Cyclooxygenase-2 and Nitric Oxide Synthase 2 in Swine Ulcerative Colitis Caused by Salmonella typhimurium
Authors: Cho W.-S. , Chae C.
Published: July 2004

Cyclooxygenase-2 (COX-2) and nitric oxide synthase 2 (NOS2) were detected and localized in 20 pigs with ulcerative colitis caused by natural infection with Salmonella typhimurium. Evidence of NOS2 activity was determined by the formation of nitrotyrosine, a reaction product of peroxynitrite, in NOS2-expressing ulcerative colons by immunohistochemistry. Transcript RNA of COX-2 and NOS2 was consistently detected in colonic tissues from the 20 pigs with ulcerative colitis by using reverse transcription-polymerase chain reaction. Immunohistochemical signals for COX-2 and NOS2 were detected in the ulcerated area of all 20 pigs. Expression of COX-2 and NOS2 was identified continuously within inflammatory intestinal lesions but was minimal in unaffected regions of the colon of S. typhimurium—infected pigs. The immunohistochemistry of serial sections of intestine indicated that the majority of colons containing numerous COX-2—positive cells also had numerous NOS2-positive cells. Localization of NOS2 and a nitrotyrosine antigen was prominent in neutrophils and macrophages in the periphery of the lesions. Simultaneous detection of COX-2 and NOS2 RNA and protein indicated functional activity of prostaglandin and NO production in vivo. This study suggested that COX-2 and NOS2 expression may play a role in the pathophysiologic processes in ulcerative colitis caused by S. typhimurium.
Glioblastoma Multiforme in Three Baboons (Papio spp.)
Authors: Porter B. F. , Summers B. A. , Leland M. M. , Hubbard G. B.
Published: July 2004

Glioblastoma multiforme is the most malignant astrocytic neoplasm and the most common brain neoplasm of humans. Spontaneous neoplasms of the brain are rare in nonhuman primates. This report describes three glioblastomas in adult captive-reared baboons. The animals exhibited a range of clinical signs, including depression, weight loss, weakness, and blindness. All three neoplasms were located in the cerebrum, with extension into the pons in one case. Histologically, the tumors were similar and were characterized by cellular pleomorphism, multinucleated cells, areas of necrosis, microvascular proliferation (glomeruloid bodies), and palisading of neoplastic cells around blood vessels and areas of necrosis. Two baboons exhibited gemistocytic differentiation, and in one baboon, the neoplastic cells were predominantly spindle shaped with a fascicular growth pattern. Immunohistochemical staining for glial fibrillary acidic protein, vimentin, and S-100 protein was positive, whereas immunostaining for synaptophysin and chromogranin A was negative. Positive staining for the cell proliferation marker Ki67 ranged from 8.2% to 13.9%. Terminal deoxynucleotidyl transferase mediated dVTPnick end labeling (TUNEL) staining ranged from 1.8% to 5.7%. These baboon glioblastomas share many features with those of humans.
Thymoma-associated Exfoliative Dermatitis in Cats
Authors: Rottenberg S. , von Tscharner C. , Roosje P. J.
Published: July 2004

Five cases of exfoliative dermatitis in cats were presented from 1996 to 2002 in which a feline thymoma was found by postmortem or postsurgical examination. Besides abundant exfoliation of keratin squames and layers, the histologic picture of the skin revealed a similar pattern of interface dermatitis with predominantly CD3+ lymphocytes and fewer mast cells and plasma cells. In the epidermal basal layer a hydropic degeneration of keratinocytes was present. In all cases an infundibular lymphocytic mural folliculitis and absence of or drastic decrease in the number of sebaceous glands occurred. In addition to the so far described cell-poor type, we also found examples of a cell-rich skin lesion. Together with the clinical observation of generalized exfoliative dermatitis, the histologic pattern of this dermatitis was suggestive of an underlying thymoma. The pathogenesis of this skin disease in association with thymic neoplasia remains obscure, and our results contradict the hypothesis of production of autoantibodies that cross-react with epithelial antigens. The morphology of the thymomas and CD3 expression of the thymocytes varied and did not seem to have an impact on the dermal lesions.
Invasive Ability of Escherichia coli O18 Isolated from Swine Neonatal Diarrhea
Authors: Wada Y. , Kato M. , Yamamoto S. , Shibahara T. , Ishikawa Y. , Kadota K.
Published: July 2004

Neonatal diarrhea occurred at two swine breeding farms in Hokkaido. Ten piglets aged 2 to 4 days were examined. Grossly, significant changes were confined to the small intestine. The mucous membrane was muddy and thickened. The intraluminal contents from the jejunum to the colon were liquid and yellow. In the small intestine, numerous Gram-negative bacilli preferentially adhered to the apex of villi. The mucosa was erosive with villous atrophy. There were bacilli also in the lamina propria and in the cytoplasm of degenerated enterocytes. Nonhemolytic Escherichia coli strains, belonging to serogroup E. coli O18 and possessing K88 fimbriae, were isolated from the small intestine. They could not be classified into any of the diarrheagenic E. coli groups because of the absence of genes of LT, STh, STp, VT1, VT2, eae, invE, and ipaH. After inoculation of the isolates on HEp-2 cells, some bacilli were engulfed by cytoplasmic projections resembling membrane ruffles and subsequently were localized in cytoplasmic vacuoles or free in the cytoplasm. These findings support the view that the present E. coli O18 is a new invasive strain enteropathogenic to piglets.
A Peripheral Primitive Neuroectodermal Tumor with Generalized Bone Metastases in a Puppy
Authors: De Cock H. E. V. , Busch M. D. M. , Fry M. M. , Mehl M. , Bollen A. W. , Higgins R. J.
Published: July 2004

A peripheral primitive neuroectodermal tumor (pPNET), most consistent with a human Ewing's sarcoma, is described in a 5-month-old male Australian Shepherd puppy. The first tumor site detected was in the left frontal bone of the skull with apparent subsequent rapid metastases to multiple sites in the axial and appendicular skeleton and bone marrow, kidneys, and perihyphophyseal meninges. Radiographically, all bone lesions were lytic and there was also a humeral bone fracture. Histologically, the tumor was diagnosed as a small round blue cell tumor. At this stage, the differential diagnosis included a lymphoma, rhabdomyosarcoma, and a PNET of the peripheral nervous system. However, the cells had positive expression of triple neurofilament antigens as detected immunocytochemically. The cells were negative for a broad panel of canine-specific leucocyte cell marker antigens for desmin, smooth muscle actin, synaptophysin, and CD99. Ultrastructurally, the cells contained occasional dense core neurosecretory granules and intermediate filaments with intercellular desmosomal-like junctions and abundant glycogen clusters. Based on the age of the dog, the clinical history, the distribution of gross lesions, histologic characteristics of a small round blue cell tumor, and immunocyto-chemical and ultrastructural evidence of neuroectodermal differentiation, a diagnosis of a pPNET similar to a human Ewing's sarcoma was made.
Transcription Factor GATA-4 Is a Marker of Anaplasia in Adrenocortical Neoplasms of the Domestic Ferret (Mustela putorius furo)
Authors: Peterson R. A. , Kiupel M. , Bielinska M. , Kiiveri S. , Heikinheimo M. , Capen C. C. , Wilson D. B.
Published: July 2004

Adrenocortical neoplasms are a common cause of morbidity in neutered ferrets. Recently we showed that gonadectomized DBA/2J mice develop adrenocortical tumors that express transcription factor GATA-4. Therefore, we screened archival specimens of adrenocortical neoplasms from neutered ferrets to determine whether GATA-4 could be used as a tumor marker in this species. Nuclear immunoreactivity for GATA-4 was evident in 19/22 (86%) of ferret adrenocortical carcinomas and was prominent in areas exhibiting myxoid differentiation. Normal adrenocortical cells lacked GATA-4 expression. Two other markers of adrenocortical tumors in gonadectomized mice, inhibin-α and luteinizing hormone receptor, were coexpressed with GATA-4 in some of the ferret tumors. No GATA-4 expression was observed in three cases of nodular hyperplasia, but patches of anaplastic cells expressing GATA-4 were evident in 7/14 (50%) of tumors classified as adenomas. We conclude that GATA-4 can function as a marker of anaplasia in ferret adrenocortical tumors.
Evaluation of antimicrobial peptide nisin as a safe vaginal contraceptive agent in rabbits: in vitro and in vivo studies
Authors: Reddy K V R , Aranha C , Gupta S M , Yedery R D
Published: July 2004

In the midst of the global epidemics of both unwanted pregnancies and sexually transmitted infections (STIs), options that provide protection are ideal. In the present study, nisin, a known antimicrobial peptide, was evaluated for safety and contraceptive potentialin vitroandin vivoin the rabbit. A concentration of 400 μg nisin per ml was found to be spermicidalin vitro, and the effect was dose and time dependent.In vivostudies indicated that intravaginal application of 1 mg nisin blocked conception in rabbits. Repeated application of nisin (50 mg/animal per day) in rabbits for 14 consecutive days did not cause local inflammation or damage to the vaginal epithelium. In addition, the rate of diffusion of nisin into the blood via the vaginal mucosal epithelium, and its clearance from the circulation was found to be rapid. No treatment-related changes were observed in the reproductive performance of rabbits after cessation of treatment. Furthermore, no changes were observed in the gestation period, subsequent growth and survival of neonates in these animals. When male rats were given nisin orally for 13 consecutive weeks, no effect was observed on reproductive performance. The number of pups born, survival and growth of pups were unaltered. The affinity studies of nisin revealed that spermatozoa are more susceptible to nisin than red blood cells and vaginal epithelial cells. We suggest that nisin with spermicidal and antimicrobial properties could serve as a safe vaginal contraceptive for future therapeutic interventions in STIs.
Microcanalization in the epididymis to overcome ductal obstruction caused by chronic exposure to chromium – a study in the mature bonnet monkey (Macaca radiata Geoffroy)
Authors: Aruldhas M Michael , Subramanian S , Sekhar P , Hasan G Chandra , Govindarajulu P , Akbarsha M A
Published: July 2004

In order to apprehend the toxic effects of chromium, an occupational/environmental pollutant, on the epididymis, adult bonnet monkeys were exposed to chromium (VI) in their drinking water at concentrations of 100, 200 and 400 p.p.m. for a chronic period of 180 days. At the end of the experimental period, testicles and segments of epididymis from control and treated monkeys were subjected to light microscopic (resin-embedded semi-thin sections) and transmission electron microscopic analyses. Among the various changes undergone by the epididymal epithelium, the present paper describes the origin of two different kinds of microcanals, probably caused by ductal obstruction. The first type of microcanal, which appears to provide passage for spermatozoa to bypass the obstructed main duct, is comparable with the one already reported in carbendazim-treated efferent ductules of the rat. The second type of microcanal, which is novel, consisted of a lumen in the epithelium enclosed by four to five cells, which are either modified basal cells, principal cells or a hitherto unknown cell type. This novel type of microcanal is suggested to be a device to entrap the spermatozoa which reach the core of the epithelium and may be a mechanism to prevent extravasation of sperm so as to avoid an autoimmune response of spermatic granuloma formation. Thus, the present study has shown that chronic exposure to chromium (VI) through drinking water can produce pathological manifestations in the epididymal epithelium but the epididymis, being a versatile organ, is capable of overcoming such adverse situations through novel devices.
Trophoblast differentiation in vitro: establishment and characterisation of a serum-free culture model for murine secondary trophoblast giant cells
Authors: El-Hashash A H K , Kimber S J
Published: July 2004

Differentiation of trophoblast giant cells is an early event during the process of murine embryo implantation. However, differentiation of secondary trophoblast giant cells in the rodent is still only partially understood, probably because of the lack of suitablein vitromodels and cell markers. In order to advance our understanding of trophoblast differentiation, suitablein vitromodels and markers are required to study their development. The objectives of this study were to establish and characterise a serum-freein vitromodel for murine secondary trophoblast cells. Secondary trophoblast giant cells growingin vitroand paraffin sections of day 8.5 postcoitum mouse embryos were processed for immunostaining to establish the expression of potential markers using antibodies to blood group antigens, E-cadherin, α7integrins and activator protein-γ, as well as placental lactogen-II. Within 3 days in serum-free culture, ectoplacental cone-derived secondary trophoblast cells underwent simultaneous induction of both morphological and functional differentiation. Secondary trophoblasts grewin vitroas a monolayer of cells with giant nuclei and expressed B and Le-b/Le-y blood group antigens, α7integrins and placental lactogen-II, as well as activator protein-γ. Transcripts for activator protein-γ and placental lactogen-II were detected in cultures by RT-PCR and for placental lactogen-II byin situhybridisation. At later time-points apoptosis increased. A fibronectin substrate significantly increased secondary trophoblast cell numbers and surface area of outgrowth. The increase in cells with giant nuclei coincided with induction of placental lactogen-II expression. A relationship was found between the nuclear area of secondary trophoblast cells and expression of placental lactogen-II.
Testis-specific transcription mechanisms promoting male germ-cell differentiation
Authors: Kimmins Sarah , Kotaja Noora , Davidson Irwin , Sassone-Corsi Paolo
Published: July 2004

Male germ-cell differentiation requires spermatogenic stage- and cell-specific gene expression that is achieved by unique chromatin remodeling, transcriptional control and the expression of testis-specific genes or isoforms. Recent findings have shown that the testis has specialized transcription complexes that coordinate the differentiation program of spermatogenesis. There are male germ cell-specific differences in the components of the general transcription machinery. These include upregulated expression of the TATA-binding protein (TBP) family and its associated cofactors. Importantly, a member of the TBP family, TBP-like factor (TLF), has a distribution pattern that is dependent on the spermatogenic cycle and is essential for spermatogenesis. Interestingly TBP-associated factor (TAF7), a factor of the transcription factor (TF)IID complex, is exchanged at a critical stage in germ cell development for the testis-specific paralogue TAF7L. A compelling amount of data has established that cAMP-response-element modulator (CREM), a transcription factor responsive to the cAMP signal transduction pathway, drives expression of key testis-specific genes. In this review we summarize recent advances in the transcription machinery that is testis-specific, gene-selective and necessary for the process of spermatogenesis.
Influence of mutations affecting gonadotropin production or responsiveness on expression of inhibin subunit mRNA and protein in the mouse ovary
Authors: Hirst Rachel C , Abel Margaret H , Wilkins Vivienne , Simpson Christine , Knight Phil G , Zhang Fu-Ping , Huhtaniemi Ilpo , Kumar T Rajendra , Charlton Harry M
Published: July 2004

Measurement of inhibins A and B in the serum of normal cyclic rodents has implicated FSH in the regulation of these peptides within the ovary. To extend these observations we have used a panel of mutant mice carrying mutations which affect either the production of, or the ability to respond to, FSH and LH. As a consequence, the females are infertile and show different degrees of follicular development. The aim of this study was to measure inhibin gene transcription in the ovaries of these mutant females together with inhibin protein levels in ovaries and serum and to relate these to follicular development within the ovary. Comparison was made with a pool of normal/heterozygous females. In hpg females where lack of GnRH production results in the absence of gonadotropin synthesis, in FSHβ knockout (FSHβKO) females where disruption of the gene encoding FSHβ results in the absence of FSH production, and in FSH receptor knockout (FSHRKO) females which are unable to respond to circulating FSH, follicular development remains at the pre-antral stage in these three mutants. Only in the hpg females were common inhibin α subunit mRNA levels significantly lower than normal. In these three mutants, however, mRNA levels for both the βA and βB subunits were extremely low compared with normal mice. At the protein level, neither inhibin A nor B was detected in the serum of these three mutants; however inhibin B, albeit at very low levels, was detectable within the ovaries. These observations confirm a major role for FSH in the control of transcription of the βA and βB genes but suggest that the constitutive transcription of the alpha subunit is less dependent on FSH. In contrast, in LH receptor knockout (LuRKO) female mice inhibin βA subunit mRNA levels were similar to those measured in normal/heterozygous females but levels of inhibin α and βB subunit mRNAs were significantly higher than in the normal group. This was reflected in significantly higher inhibin B protein levels in ovaries and serum. An inability to respond to LH combined with high circulating levels of FSH leads to a high proportion of antral follicles in LuRKO females, with granulosa cells constituting the major cell type within the ovary. The high percentage of antral granulosa cells is likely to account for the significantly higher levels of inhibin B production in these ovaries.
Food Additives
Authors: Friedman Leslie J. , Greenwald C. Gail
Published: June 2004

Food additives provide many important benefits to food and beverage products. These benefits range from enhancement of the flavor and texture of the product, to safeguarding it from oxidative deterioration or microbial spoilage. Food additives are defined and closely regulated at the national level.

This chapter provides a brief overview of 24 categories of food additives and ingredients, excluding bulk ingredients such as flour, sugar, fats, and oils. These categories comprise hundreds of individual compounds, representing the majority of those in common use in the food system. Typical food applications of each additive are identified, and the important technical and functional properties are described. Data on the manufacturers and markets of food additives are also included.
Germanium and Germanium Compounds
Authors: Adams Jack H. , Thomas Dennis
Published: June 2004

Germanium is a semiconducting metalloid element found in Group 14 (IVA), Period 4 of the Periodic Table. Although it looks like a metal, it has a diamond cubic crystal structure and is fragile like glass. Its electrical resistivity is about midway between that of metallic conductors and good electrical insulators. The first significant use was in solid‐state electronics, and, using germanium, the transistor was invented. The entire modern field of semiconductors owes it development to the early successful use of germanium. Whereas germanium is still used in the field of electronics, its use in infrared optics surpassed electronic applications in the 1970s. Germanium has also found widespread use in the fields of γ‐ray spectroscopy, catalysis, fiber optics, and photovoltaic cells. Germanium usually occurs widely dispersed in minerals. Most germanium production has been from zinc smelters and copper smelters.

Germanium also occurs in significant concentrations in many coals around the world. Germanium is quite stable in air up to 400°C, where slow oxidation begins. The metal resists concentrated acid and alkali. Many Ge alloys have been prepared and studied.

No mineral is mined solely for its germanium content. Almost all of the Ge recovered worldwide is a by‐product of other mining. Germanium compounds generally have a low order of toxicity.
High Performance Fibers
Authors: Polk Malcolm , Vigo Tyrone L. , Turbak Albin F.
Published: June 2004

The preparation, processing, and properties of high performance fibers are critically reviewed. The principal classes of high performance fibers discussed are those derived from rigid‐rod polymers, gel spun fibers, modified carbon fibers, synthetic vitreous fibers, and poly(phenylene sulfide) fibers. Rigid‐rod polymers are derived from lyotropic crystalline polymers, such as the aramids Nomex and Kevlar or thermotropic liquid crystalline polymers, such as Vectran. These fibers are generally characterized by remarkable unit tensile strength and resistance to heat, flame, and chemical agents that normally degrade conventional fibers. Applications for these fibers are classified by structural aspects of the fiber, yarn, and fabric levels. Diversities in applications include uses in the aerospace, biomedical, civil engineering, construction, protective apparel, geotextile, and electronic areas.
Magnesium Compounds
Authors: Jackson L. C. , Levings S. P. , Maniocha M. L. , Mintmier C. A. , Reyes A. H. , Scheerer P. E. , Smith D. M. , Wajer M. T. , Walter M. D. , Witkowski J. T.
Published: June 2004

A variety of magnesium compounds and minerals are found both in seawater and in the earth's crust. Commercial magnesium compounds are widely used in chemical processing, whether in the production of paper or rayon fiber, or as a catalyst, filler, flame retardant, alkaline material, stable coating for magnetic recording media, or wastewater or flue gas scrubber. Magnesium hydroxide is a common over‐the‐counter antacid and laxative. Additionally, the branch of synthetic organic chemistry known as Grignard reactions is based on magnesium compounds. Magnesium forms stable salts with most common anions, such as acetate, carbonate, the halides, hydroxide, oxide, and sulfide, as well as with some less common ones such as vanadates. Many magnesium alkyls are also known. The production, properties, uses, safe handling, and analysis of the commercial magnesium compounds are described.
The Role of Research in the Practice of Adult Education
Authors: Quigley B. Allan
Published: July 2004

The research traditions of adult education, the issue of who should produce research‐based knowledge, and a proposed new framework for research methods for the future of the field are discussed.
Reflections on Action Research
Authors: Peters John M.
Published: July 2004

John Peters, from the University of Tennessee, gives his critical reflections on the text.
The Grieving Soul in the Transformation Process
Authors: Scott Sue M.
Published: July 2004

When we transform, we lose an old self, and we grieve for that loss. Analytical
depth psychology provides a framework for understanding the grieving
process in transformative learning.
I Ain't So Smart, and You Ain't So Dumb: Personal Reassessment in Transformative Learning
Authors: Cohen Laurence Robert
Published: July 2004

What do we do when the world has consistently told us we are dumb? We
believe it. Adult learners can undo this damage through a reassessment of
their personal perspectives.
The Assessment of Noncollegiate Sponsored Programs of Instruction
Authors: Hamilton Richard J.
Published: July 2004

The origins of the Program on Noncollegiate Sponsored Instruction are explored and its processes are outlined; the remainder of the chapter discusses the issues surrounding use of the program in higher education today.
Negotiating Power Dynamics in Workshops
Authors: Johnson‐Bailey Juanita , Cervero Ronald M.
Published: July 2004

Workshops are not as effective as they could be because planners and teachers
have not paid systematic attention to issues of power relationships that
stem from individuals' places in the hierarchies of our social world.
Workshops at a Distance
Authors: Gibson Chere Campbell , Gibson Terry L.
Published: July 2004

The authors describe the array of instructional technologies available for
delivering education at a distance and emphasize creating successful learning
experiences for learners rather than simply providing access to information.
New Vistas for Adult Education
Authors: Edelson Paul Jay , Malone Patricia L.
Published: June 2004

Mastery, plasticity, a vision for the future, and a commitment to ongoing experimentation will bring forth continuing education worthy of our field's ideals.
Team Teaching and Learning in Adult Education: From Negotiating Relationships to Implementing Learning Alternatives
Authors: Tisdell Elizabeth J. , Eisen Mary‐Jane
Published: June 2004

Three themes that connect the chapters of this volume are highlighted
here: attending to team relationships, attending to team tasks, and co‐constructing
knowledge.
Print
Authors: O'Rourke Jennifer
Published: June 2004

Print provides a model for many other learning technologies. Good design and thoughtful applications can make the best use of its main assets—durability, flexability, and accessibility.
Potential New Matrix Alloys for production of PM Aluminium Foams
Authors: Lehmhus D. , Busse M.
Published: July 2004

The powder compact melting technique for aluminium foam production as practised today accepts a certain mismatch between foaming agent decomposition and matrix alloy melting temperatures. This mismatch is believed to influence the pore structure in an unfavourable way. Adjustment of TiH2 decomposition as well as liquidus and solidus temperatures of matrix alloys can be used to counteract it. Effects of TiH2 thermal treatments are investigated using thermal analysis. TiH2 variants gained via annealing treatments were used to produce aluminium foam precursor materials. As matrix for these specimens, aluminium based alloys with low liquidus and solidus temperatures were selected. Alloy systems considered include established combinations of aluminium with Cu, Mg, Si and Zn as well as special quaternary mixtures of these elements. First examinations presented include thermal analysis of alloys as well as studies on expansion vs. time and temperature relationships of precursor material based on new alloys and foaming agent variants.
Production of Metallic Foams From Ceramic Foam Precursors
Authors: Verdooren A. , Chan H.M. , Grenestedt J.L. , Harmer M.P. , Caram H.S.
Published: July 2004

A process has been developed for obtaining closed cell metallic foams using a ceramic foam precursor. In this approach, the major constituent of the ceramic foam precursor is iron oxide (Fe2O3), which is mixed with various foaming/setting additives. The mixture sets rapidly at room temperature to stabilize the foam generated by hydrogen release. The oxide foam is then reduced in a non‐flammable hydrogen/inert gas mixture to obtain a metallic foam with a cell diameter of 0.5–2 mm. Iron foams with a relative density of 0.23 were tested in compression and yielded an average compressive strength of ∼ 34 MPa. The compressive stress‐strain curves obtained were typical of cellular metals. The normalized strengths of the metal foams obtained in the present study compare very favorably with that of steel foams produced by other techniques.
Porous TiNi Biomaterial by Self‐Propagating High‐Temperature Synthesis
Authors: Kim J.S. , Kang J.H. , Kang S.B. , Yoon K.S. , Kwon Y.S.
Published: July 2004

Porous TiNi shape‐memory alloy (TiNi SMA) bodies with controlled pore structure were produced from the (Ti+Ni) powder mixture by self‐propagating high‐temperature synthesis (SHS) method. The effect of processing variables such as the kind of starting powders, ignition temperature and preheating schedule on the behavior of combustion wave propagation, the formation of phases and pore structure was investigated. The relationship between pore structure and mechanical properties was also investigated. An in vivo test was performed to evaluate bone tissue response and histocompatibility of porous TiNi SMA using 15 New Zealand white rabbits. No apparent adverse reactions such as inflammation and foreign body reaction were noted on or around all implanted porous TiNi SMA blocks. Bone ingrowth was found in the pore space of all implanted blocks.
Grain Size Effects on the Mechanical Behavior of Open‐cell Nickel Foams
Authors: Goussery V. , Bienvenu Y. , Forest S. , Gourgues A.‐F. , Colin C. , Bartout J.‐D.
Published: July 2004

The dependence of the mechanical behavior of nickel foams upon their grain size was studied. First, the grain coarsening phenomenon which occurs during the processing of foams was analyzed. A metallurgical characterization of the grain growth during heat treatment was performed. The grain size effects on the mechanical properties was then studied, namely, via the Hall‐Petch law. The foam walls being very thin, roughly 10 μm in thickness, grain growth and mechanical behavior might be different compared with conventional materials. The present results obtained with foams were compared with literature data on bulk pure nickel and with nickel foils of 10 and 50 μm in thickness which are good candidates for the modeling of the cell walls. The EBSD technique allowed observing the absence of preferred crystallographic orientations for both foams and foils. A mechanical model in the spirit of that by Gibson and Ashby was finally presented incorporating the grain size effect on yield strength and hardening modulus. This model provided a good estimation of the experimental data.
Online temperature measurement and simultaneous diameter estimation of fibers by thermography of the spinline in the melt spinning process
Authors: Golzar M. , Beyreuther R. , Brünig H. , Tändler B. , Vogel R.
Published: July 2004

Online measurements of the temperature and the diameter of fibers in the melt spinning process of thermoplastics are discussed. The temperature and the diameter of fibers can be applied in many fields such as fiber formation modelling, cooling rate behavior (Nusselt number), and rheological investigations (apparent extensional viscosity) of polymers. The online measurements along the spinline were carried out with an infrared camera during the melt spinning process. Two different experiments were designed and carried out to find the correction factor, i.e., the emissivity. The results show that the emissivity correction factor depends on the polymer type and the fiber diameter. Usually the diameter of the fibers is measured by an instrument or by direct velocity measurements invoking the continuity equation. In this new approach the diameter is found directly by the evaluation of the measured temperature. Therefore only one apparatus, namely an infrared camera taking snapshots, is required to find the fiber diameter. The key of this method can be seen in the temperature difference between the fiber and the environment. A mathematical procedure was developed to estimate the diameter of the fiber from the distribution curve. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 176–185, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20008
A study of grafting reactions during processing of polyolefins
Authors: Machado A. V. , Covas J. A. , van Duin M.
Published: July 2004

The effects of polyolefins composition, that is polyethylene (PE), polypropylene (PP) and a ethylene/propylene copolymer (EPM) of 45/55 monomer ratio, and of operating conditions (screw speed, throughput and screw configuration) on the grafting of maleic anhydride (MA) were investigated. Sampling devices located along the extruder barrel were used to collect samples of modified PE, EPM, and PP that were subsequently characterized in order to monitor the degree of grafting and of crosslinking/degradation. Although a similar trend of MA grafting evolution is observed along the extruder, the final MA graft content depends on the processing parameters, screw configuration, and particularly, throughput have a significant effect on the grafting yield. Taking PE as an example, and by means of a statistical experimental design, an optimal operating window in terms of screw speed, throughput, and geometry was identified, yielding MA graft contents of 2 wt% MA. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 196–210, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20011
Reactive extrusion of poly(urethane‐isocyanurate)
Authors: Semsarzadeh M. A. , Navarchian A. H. , Morshedian J.
Published: July 2004

Reactive extrusion of poly(urethane‐isocyanurate) (PUIR) was studied in an intermeshing corotating twin‐screw extruder. Toluene diisocyanate (TDI) and polypropylene glycol (PPG) were used as initial materials with dibutyltin dilaurate (DBTDL) as catalyst. The reaction was first examined in a batch reactor as well as in an internal mixer in order to obtain the kinetics and temperature/torque evolution trends during the formation of PUIR, respectively. For the specified screw speed and temperature profile of the extruder, a working domain can be recommended for the reactive extrusion, in terms of NCO/OH ratio (r) and catalyst concentration (C), to reach a sufficient extent of reaction. The effects of screw speed and temperature profile on the residence time parameters of the reaction mixture were investigated. It is found that the axial mixing and the RTD behavior of the reaction mixture in the extruder can be well represented by the axial dispersion model. For the reaction condition of r = 3, C = 2%, and barrel temperature profiles of 75–150°C or 90–165°C, the optimum screw rotation speed for complete NCO conversion is 20 rpm. The structures, thermal stabilities, morphologies, and physical and dynamic mechanical properties of reactively extruded PUIRs were investigated. © 2004 Wiley Periodicals, Inc. Adv Polym Techn 23: 239–255, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/adv.20014
Breast cancer genetics: Unsolved questions and open perspectives in an expanding clinical practice
Authors: Hodgson Shirley V. , Morrison Patrick J. , Irving Melita
Published: July 2004

Breast cancer is the most common cause of cancer death in the United Kingdom, with a lifetime risk of one in nine in women. Only 5–10% of all cancers is thought to be due to strongly penetrant inherited predisposing genes, such as BRCA1 and BRCA2. However, other less penetrant genes, including some autosomal recessive genes, are likely to be of etiological importance in other families. This review addresses the current knowledge of breast cancer susceptibility genes and explores the possibilities for future developments. Features of tumor pathology, prognosis, and the scope for targeted treatments in mutation carriers are discussed, and the management of known carriers and those at increased risk for developing breast cancer are evaluated. Genetic testing for cancer susceptibility may become widely available in the future, and has important ethical and management implications. © 2004 Wiley‐Liss, Inc.
Reduktion von N2O an einem μ4‐sulfidverbrückten vierkernigen aktiven CuZ‐Zentrum
Authors: Chen Peng , Gorelsky Serge I. , Ghosh Somdatta , Solomon Edward I.
Published: June 2004

Die Reduktion von Distickstoffoxid (N2O) ist eine chemische Herausforderung, sowohl was die selektive Oxidation organischer Substrate durch N2O anbelangt als auch die Beseitigung von N2O als Treibhausgas. Die Reduktion von N2O ist thermodynamisch günstig, aber kinetisch gehemmt und erfordert die Aktivierung von N2O durch Übergangsmetallzentren. In biologischen Systemen ist die Reduktion von N2O der abschließende Denitrifizierungsschritt im bakteriellen Stickstoffkreislauf und wird von dem Enzym Distickstoff‐Reduktase katalysiert, dessen aktives Zentrum aus einem μ4‐sulfidverbrückten vierkernigen CuZ‐Cluster mit vielen ungewöhnlichen spektroskopischen Eigenschaften besteht. Aktuelle Untersuchungen führten zu einer detaillierten Beschreibung der elektronischen Struktur des CuZ‐Clusters im Ruhezustand und im katalytisch aktiven Zustand. Dies führt zum besseren Verständnis der Rolle dieses vierkernigen Kupferclusters bei der Aktivierung und Reduktion von N2O.
Semicontinuous emulsion copolymerization of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose (3‐MDG) and butyl acrylate (BA). Monomer feed addition
Authors: Al‐Bagoury Mohamed , Yaacoub Emile‐Joseph
Published: June 2004

New polymer colloids based on the saccharide monomer, using of 3‐O‐methacryloyl‐1,2:5,6‐di‐O‐isopropylidene‐α‐D‐glucofuranose (3‐MDG), were prepared by semicontinuous emulsion polymerization, a widely used industrial process. The copolymerization of 3‐MDG and butyl acrylate (BA), by the monomer‐addition technique, at 70°C, using sodium persulfate (Na2S2O8) as an initiator, was investigated. The influence of some reaction parameters, such as the type and concentration of the surfactants as well as the monomer addition rate (Rm) on the polymerization rate (Rp), the colloidal properties, and the stability of the latexes, was studied. It was found that under starved‐feed conditions the polymerization rate and the particle size (D) increased with an increasing rate of monomer addition. The weight‐average molecular weight (Mw) also increased by enhancing Rm and a narrower molecular weight distribution was obtained. Furthermore, the type and the concentration of the surfactants strongly influenced the particle size and its distribution. The effect of the seed stage on the particle size and its distribution was also investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2091–2102, 2003
The role of historical dolphin takes and habitat degradation in shaping the present status of northern Adriatic cetaceans
Authors: Bearzi Giovanni , Holcer Drasko , Notarbartolo di Sciara Giuseppe
Published: June 2004

Nine cetacean species have been reliably reported to occur in the shallow northern Adriatic Sea since the 17th century. However, only two species were considered regular there until the 1970s: the short‐beaked common dolphin (Delphinus delphis) and the common bottlenose dolphin (Tursiops truncatus).

Short‐beaked common dolphins have progressively disappeared from the northern Adriatic and are now rare in the region. The systematic culling campaigns and other takes that occurred between the second half of the 18th century and the 1960s, and habitat degradation in subsequent years are the most likely causes of their decline.

Today, common bottlenose dolphins are the only regular component of the northern Adriatic cetacean fauna; however, they now occur at low densities, and their fragmented groups are facing significant anthropogenic threats.

The future of northern Adriatic dolphins will depend on precautionary action to prevent further decline and on intensified research effort aimed at identifying the most effective mitigation strategies.

Copyright © 2004 John Wiley & Sons, Ltd.
A simple method for assessing minimum flows in regulated rivers: the case of sea lamprey reproduction
Authors: Oliveira João M. , Ferreira Maria T. , Pinheiro António N. , Bochechas Jorge H.
Published: July 2004

The sea lamprey (Petromyzon marinus) is an anadromous species that occurs in some large Iberian rivers, such as the Tagus, and their tributaries. The sea lamprey populations of the River Tagus are threatened by habitat loss and overexploitation, which means that conservation measures, including maintenance of the spawning grounds, are urgent. Habitat loss is mainly due to hydroelectric and flood‐control dams that have affected the migration and spawning habitats of anadromous species. The main objective of this study was to use a simple, cost‐effective method to assess a minimum instream flow for the regulated River Tagus. The method used was based on the wetted perimeter–discharge relationship, but accounted for the habitat requirements of spawning sea lampreys.

In 1998, a habitat survey was conducted along a 30 km segment of the River Tagus downstream from Belver Dam (the first impassable obstacle for fish movements), a stretch that includes potential habitats for spawning sea lampreys. Four spawning areas were identified, and in each one a representative reach was selected along which to collect elevation and geo‐positional data. For a range of flows from 0 to 50 m3 s−1, hydraulic modelling and studies of spawning habitat availability were conducted, both for each reach and for the total wetted area of the four reaches.

The availability of spawning habitat was limited by flow. Results showed that the present minimum flow downstream from Belver Dam (8 m3 s−1) is insufficient to ensure suitable habitat conditions in a significant part of the segment studied; gains in wetted usable area were more substantial with discharges of up to 20 m3 s−1, and thus a minimum flow of 10–20 m3 s−1 was recommended. Potential spawning habitat could be improved by increasing instream flow to at least 50 m3 s−1. The impacts of the Belver release regime on anadromous species are discussed and a more ‘ecologically oriented’ form of water management is suggested

. Copyright © 2004 John Wiley & Sons, Ltd.
Fish fauna in Iberian Mediterranean river basins: biodiversity, introduced species and damming impacts
Authors: Clavero Miguel , Blanco‐Garrido Francisco , Prenda José
Published: July 2004

A basin approximation was used to analyse distribution patterns of different components of biodiversity (taxonomic richness, endemicity, taxonomic singularity, rarity) and conservation status of freshwater fish fauna in 27 Mediterranean Iberian rivers.

Basin area alone explained more than 80% of variation in native species richness. Larger basins featured not only a higher number of native species, but also more endemic and rare species and fewer diversified genera than smaller basins.

In contrast, smaller basins scored higher community conservation values, owing to their lower degree of invasion by introduced species.

The presence of dams was the most important factor determining the conservation status of fish communities, and it was also positively associated with the number of introduced species.

While the most important components of Iberian freshwater fish biodiversity are located in large basins, small unregulated basins feature better conserved fish communities.

Copyright © 2004 John Wiley & Sons, Ltd.
Simultaneous Non‐inferiority Test of Sensitivity and Specificity for Two Diagnostic Procedures in the Presence of a Gold Standard
Authors: Chen James J. , Hsueh Huey‐miin , Liu Jen‐pei
Published: June 2004

Sensitivity and specificity have traditionally been used to assess the performance of a diagnostic procedure. Diagnostic procedures with both high sensitivity and high specificity are desirable, but these procedures are frequently too expensive, hazardous, and/or difficult to operate. A less sophisticated procedure may be preferred, if the loss of the sensitivity or specificity is determined to be clinically acceptable. This paper addresses the problem of simultaneous testing of sensitivity and specificity for an alternative test procedure with a reference test procedure when a gold standard is present. The hypothesis is formulated as a compound hypothesis of two non‐inferiority (one‐sided equivalence) tests. We present an asymptotic test statistic based on the restricted maximum likelihood estimate in the framework of comparing two correlated proportions under the prospective and retrospective sampling designs. The sample size and power of an asymptotic test statistic are derived. The actual type I error and power are calculated by enumerating the exact probabilities in the rejection region. For applications that require high sensitivity as well as high specificity, a large number of positive subjects and a large number of negative subjects are needed. We also propose a weighted sum statistic as an alternative test by comparing a combined measure of sensitivity and specificity of the two procedures. The sample size determination is independent of the sampling plan for the two tests.
Estimation of Additive Genetic Variance Components in Aquaculture Populations Selectively Pedigreed by DNA Fingerprinting
Authors: Li X. , Field C. , Doyle R.
Published: June 2004

A method to estimate genetic variance components in populations partially pedigreed by DNA fingerprinting is presented. The focus is on aquaculture, where breeding procedures may produce thousands of individuals. In aquaculture populations the individuals available for measurement will often be selected, i.e. will come from the upper tail of a size‐at‐age distribution, or the lower tail of an age‐at‐maturity distribution etc. Selection typically occurs by size grading during grow‐out and/or choice of superior fish as broodstock. The method presented in this paper enables us to estimate genetic variance components when only a small proportion of individuals, those with extreme phenotypes, have been identified by DNA fingerprinting. We replace the usual normal density by appropriate robust least favourable densities to ensure the robustness of our estimates.

Standard analysis of variance or maximum likelihood estimation cannot be used when only the extreme progeny have been pedigreed because of the biased nature of the estimates. In our model‐based procedure a full robust likelihood function is defined, in which the missing information about non‐extreme progeny has been taken into account. This robust likelihood function is transformed into a computable function which is maximized to get the estimates. The estimates of sire and dam additive variance components are significantly and uniformly more accurate than those obtained by any of the standard methods when tested on simulated population data and have desirable robustness properties.
How to Detect Biased Samples?
Authors: Navarro J. , Ruiz J.M. , del Aguila Y.
Published: June 2004

In this paper we study some methods to detect biased samples and to test what is the bias. These methods can be also used to obtain parametric tests for the original model. We pay special attention to the case of length (size) biased samples. We apply these results to several real and simulated samples.
Surface Plasmon Resonance Evaluation of Various Aminoglycoside–RNA Hairpin Interactions Reveals Low Degree of Selectivity
Authors: Verhelst Steven H. L. , Michiels Paul J. A. , van der Marel Gijsbert A. , van Boeckel Constant A. A. , van Boom Jacques H.
Published: July 2004

Aminoglycoside antibiotics, which are able to selectively bind to RNA, are considered to be an important lead in RNA‐targeting drug discovery. In this study, surface plasmon resonance (SPR) was employed to explore the interaction of aminoglycosides with known tobramycin‐binding RNA hairpins (aptamers) and an unrelated RNA hairpin. It was established that aminoglycosides have multiple interactions with RNA hairpins. Unexpectedly, the different hairpins showed comparable affinity for a set of related aminoglycosides. The observed absence of selectivity presents an extra hurdle in the discovery of novel aminoglycosides as specific drugs that target defined RNA hairpins.