bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel polymer‐synthesized ceramic composite–based system for bone repair: An in vitro evaluation
Authors: Khan Yusuf M. , Katti Dhirendra S. , Laurencin Cato T.
Published: April 2004

The emergence of synthetic bone repair scaffolds has been necessitated by the limitations of both autografts and allografts. Several candidate materials are available including degradable polymers and ceramics. However, these materials possess their own limitations that at least in part may be overcome by combining the two materials into a composite. Toward that end, a novel approach to forming a polymer/ceramic composite has been developed that combines degradable poly(lactide‐co‐glycolide) microspheres and a poorly crystalline calcium phosphate that is synthesized within the microspheres, which are then fused together to form a porous three‐dimensional scaffold for bone repair. The design, fabrication, and characterization of the composite microspheres, the calcium phosphate formed within these microspheres, and the formation of scaffolds were studied. The calcium phosphate formed was analyzed by x‐ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy, and was shown to be similar to native bone in both composition and crystallinity by controlling certain processing parameters such as mixing time, solution pH, and mixing temperature. Scaffolds with porous interconnected structures and mechanical properties in the range of trabecular bone were fabricated via precise control of polymer/ceramic ratios within the microspheres and scaffold heating times. This composite scaffold represents a new and important vehicle for bone‐tissue engineering. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 728–737, 2004
Bone cement X‐ray contrast media: A clinically relevant method of measuring their efficacy
Authors: Kjellson F. , Almén T. , Tanner K.E. , McCarthy I.D. , Lidgren L.
Published: April 2004

It is important to compare different contrast media used in bone cement according to their ability to attenuate X‐rays and thereby produce image contrast between bone cement and its surroundings in clinical applications. The radiopacity of bone cement is often evaluated by making radiographs of cement in air at an X‐ray tube voltage of 40 kV. We have developed a method for ranking contrast media in bone cement simulating the clinical situation, by (1) choosing the same X‐ray tube voltage as used in clinical work, and (2) using a water phantom to imitate the effects of the patients' soft tissue on the X‐ray photons. In clinical work it is desirable to have low radiation dose, but high image contrast. The voltage chosen is a compromise, because both dose and image contrast decrease with higher voltage. Three contrast media (ZrO2, BaSO4, and Iodixanol) have been compared for degree of “image contrast.” Comparing 10 wt % contrast media samples at an X‐ray tube voltage of 40 kV, ZrO2 produced higher image contrast than the other media. However, at 80 kV, using a water phantom, the results were reversed, ZrO2 produced lower image contrast than both BaSO4 and Iodixanol. We conclude that evaluations of contrast media should be made with voltages and phantoms imitating the clinical application. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 354–361, 2004
Focal dystonia after removal of a parietal meningioma
Authors: Khan Aijaz A. , Sussman Jon D.
Published: April 2004

A patient presented at the age of 50 years with a right‐sided, writing‐specific dystonia which settled without treatment. Ten years later she developed focal seizures affecting the right leg and occasionally spreading to the right arm. A left parietal meningioma was removed and 2 years later she developed dystonic movements of her right hand. Gliotic changes were seen on magnetic resonance imaging in the superficial left parietal lobe. Mechanisms involved in the generation of dystonia associated with cortical injury are discussed. © 2004 Movement Disorder Society
The International Protein Index: An integrated database for proteomics experiments
Authors: Kersey Paul J. , Duarte Jorge , Williams Allyson , Karavidopoulou Youla , Birney Ewan , Apweiler Rolf
Published: April 2004

Despite the complete determination of the genome sequence of several higher eukaryotes, their proteomes remain relatively poorly defined. Information about proteins identified by different experimental and computational methods is stored in different databases, meaning that no single resource offers full coverage of known and predicted proteins. IPI (the International Protein Index) has been developed to address these issues and offers complete nonredundant data sets representing the human, mouse and rat proteomes, built from the Swiss‐Prot, TrEMBL, Ensembl and RefSeq databases.
A proteomic analysis of changes in prothrombin and plasma proteins associated with the G20210A mutation
Authors: Gelfi Cecilia , Viganò Agnese , Ripamonti Marilena , Wait Robin , Begum Shajna , Biguzzi Eugenia , Castaman Giancarlo , Faioni Elena Maria
Published: April 2004

The G→A mutation at position 20210 of the prothrombin gene, localized in the 3'‐polyadenylation untranslated region of the mRNA, is a recognized genetic risk factor for venous thromboembolism. The mechanism by which this base change confers an increased risk of thrombosis compared to noncarriers is undefined. Studies on the mRNA suggest enhanced cleavage site recognition and a change in the location of the 3'‐cleavage/polyadenylation reaction, but no defined model has been proposed. The present study, based on proteomic investigation by two‐dimensional gel electrophoresis and electrospray ionization (ESI) tandem mass spectrometry (MS/MS) protein identification, suggests that the G20210A mutation is associated with increased glycosylation of prothrombin, which confers greater stability to the protein. Additionally, proteomic investigation of pooled plasma showed that expression levels of six spots, three of them identified by ESI MS/MS, were altered in subjects carrying the mutation, suggesting a possible cooperative effect in the thrombotic risk increment induced by the mutation.
Organic and polymer chemistry of electrophilic tri‐ and tetrasubstituted ethylenes
Authors: Hall H. K. , Padias Anne Buyle
Published: April 2004

A survey of the spontaneous reactions of electrophilic olefins and nucleophilic olefins is presented as an area in which organic chemistry merges with polymer chemistry. The products include both small molecules and polymers, arising via tetramethylene biradical zwitterions that can cyclize or initiate polymerizations. Electrophilic tri‐ and tetrasubstituted olefins are particularly useful in delineating the transition from radical chemistry to ionic chemistry. A periodic table embodying these results enables predictions. Charge‐transfer complexes, although observed in many of these reactions, play no significant role. Various aspects arising from these investigations include new cationic initiators, Lewis acid catalysis, quinodimethane chemistry, and photochemistry. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2845–2858, 2004
Electrochemical behavior of high‐molecular‐weight poly(ferrocenylsilane) films in aqueous electrolyte solutions
Authors: Wang Xue‐Jie , Wang Li , Wang Jian‐Jun
Published: April 2004

The electrochemical behavior of high‐molecular‐weight poly(ferrocenyldimethylsilane) films and poly(ferrocenylmethylphenylsilane) films, which contained about 2.8 × 10−6 mol cm−2 ferrocene sites in eight kinds of aqueous electrolyte solutions, was investigated with cyclic voltammetry (CV). In some aqueous electrolyte solutions, the CV peak currents diminished gradually with an increase in the scanning times, whereas in other aqueous electrolyte solutions, stable and repeated cyclic voltammograms were obtained. The polymer films were poor‐solvent‐swollen in aqueous electrolyte solutions, and this resulted in a high resistivity of mass transfer and a slow rate of electrode reaction; therefore; quasireversible or irreversible CV processes were obtained. The kinetic parameters of the film‐electrode processes, such as the surface transfer coefficient, the apparent diffusion coefficient, and the standard rate constant for electron transfer, for the two films in aqueous LiClO4 solutions were measured, and the electrode process mechanism of the films was examined. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2245–2253, 2004
Nanoindentation and optical properties of poly(4,4′‐oxydiphenylene p‐phenylene pyromellitimide) copolyimide thin films according to the p‐phenylene diamine content
Authors: Lee Choonkeun , Iyer N. Padmanabha , Han Haksoo
Published: April 2004

Poly(p‐phenylene pyromellitimide) (PMDA‐PDA), poly(oxydiphenylene pyromellitimide) (PMDA‐ODA), and poly(4,4′‐oxydiphenylene p‐phenylene pyromellitimide) random copolyimide thin films with different p‐phenylene diamine (PDA) contents were prepared. Nanoindentation was used to characterize the mechanical properties (hardness and modulus), and a prism coupler was used for measuring the optical properties (refractive index and birefringence). The hardness and modulus were calculated from curves of the nanoindentation load versus the displacement. The effect of the PDA content on the hardness and modulus was studied. The hardness of the polyimide thin films varied from 0.248 to 0.613 GPa, and the modulus varied from 3.78 to 6.75 GPa at a load of 0.127 mN. The hardness and modulus increased with increasing PDA content, whereas the penetration depth and plastic deformation decreased. As the load increased, the penetration depth increased. The hardness of PMDA‐ODA films remained constant, whereas that of PMDA‐PDA and PMDA‐ODA/PDA films decreased with increasing load. The in‐plane refractive index varied from 1.7219 to 1.8244, and the out‐of‐plane refractive index varied from 1.6390 to 1.5827, as a function of the PDA content. The birefringence varied with the PDA content from 0.0829 to 0.2417. The morphological structure of the prepared polyimide thin films was investigated with wide‐angle X‐ray diffraction. The mechanical properties and optical properties of the polyimide thin films were strongly dependent on the changes in the morphological structure, which originated from the variation of the composition. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2202–2214, 2004
Atomic force microscopy observations of the structural development during the uniaxial stretching of crosslinked low‐density polyethylene in partial and fully molten states
Authors: Koike Yutaka , Cakmak Miko
Published: April 2004

The effect of uniaxial deformation in partially and fully molten states on the morphology of crosslinked low‐density polyethylene has been investigated. At low temperatures, the morphology is predominantly fibrillar, with little kebabs appearing on the fibril surfaces. As the deformation temperature is increased into the melting range, the shish density decreases, and overgrowths of kebabs on the fibrils concurrently increase in length. This gives rise to added twisting of the kebabs reflected in the orientation factor analysis. This shish/twisted lamellar kebab texture is observed only in a partially molten state. Studies in a substantially molten state indicate the absence of shish, althugh short lamellae are observed that are oriented in the transverse direction. This morphology indicates a high chain orientation factor as a result of short lamellae that exhibit small twisting similar to Matsumura's rod model. The absence of shishes in the final films stretched isothermally in a substantially molten stage agrees with Schultz's model, in which imperfectly formed shishes dissolve if they are not stabilized by rapid cooling, as is the case in these studies. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2228–2237, 2004
Heterogeneous gene methylation patterns among pre‐invasive and cancerous lesions of the prostate: A histopathologic study of whole mount prostate specimens
Authors: Woodson Karen , Gillespie John , Hanson Jeffrey , Emmert‐Buck Mike , Phillips John M. , Linehan W. Marston , Tangrea Joseph A.
Published: April 2004

BACKGROUND

Gene methylation may contribute to prostate carcinogenesis through the silencing of gene transcription. We report on the methylation status of several genes shown to be silenced at different stages of progression using whole mount prostate specimens and laser capture microdissection. This is the first study to evaluate gene methylation patterns across multiple pre‐cancerous and invasive cancer foci from the same prostate gland.

METHODS

Real‐time PCR was used to evaluate methylation of five genes (GSTP1, RASSF1A, RARβ2, CD44, and EDNRB) across normal epithelium, high‐grade prostatic intraepithelial neoplasia (HGPIN), and multiple tumor foci from each of 11 prostate cancer patients.

RESULTS

Gene methylation was not found in normal epithelium. To our knowledge, this is the first report of RASSF1A and RARβ2 methylation in HGPIN lesions (30% prevalence for each gene). In addition, RASSF1A, RARβ2, and GSTP1 methylation was highly prevalent in tumor foci (>75% for all three genes). Methylation of CD44 and EDNRB was observed in 41 and 38% of tumors but was not present in HGPIN.

CONCLUSIONS

These data suggest that genes may be methylated at different points in the histopathologic progression of prostate cancer and these differences can be found in various histologic foci from the same gland. © 2004 Wiley‐Liss, Inc.
FGF17 is an autocrine prostatic epithelial growth factor and is upregulated in benign prostatic hyperplasia
Authors: Polnaszek Nathaniel , Kwabi‐Addo Bernard , Wang Jianghua , Ittmann Michael
Published: April 2004

BACKGROUND

Fibroblast growth factors (FGFs) are known to play an important role in the growth of prostatic epithelial cells. Benign prostatic hyperplasia (BPH) is characterized by increased epithelial and stromal proliferation within the transition zone of the prostate. FGF2, FGF7, and FGF9 are expressed in BPH tissue but expression of FGF17 has not been previously characterized in human prostate tissue.

METHODS

Expression of FGF17 in human prostate tissue and primary cultures of prostatic epithelial and stromal cells was determined by reverse‐transcriptase polymerase chain reaction (RT‐PCR). Growth response to FGF17 was assessed by addition of recombinant FGF17 to immortalized normal and neoplastic epithelial cell lines and primary cultures of prostatic stromal cells in the presence of insulin. Quantitative analysis of expression of FGF17 relative to keratin 18 and/or β‐actin in normal and hyperplastic prostate and prostate carcinoma was carried out by real‐time quantitative RT‐PCR.

RESULTS

FGF17 is expressed by prostatic epithelial cells and can act as an autocrine growth factor for immortalized and neoplastic prostatic epithelial cells. It can also promote stromal proliferation, although only at higher concentrations. Expression of FGF17 per epithelial cell was increased 2‐fold in BPH.

CONCLUSIONS

FGF17 is expressed by normal, hyperplastic, and neoplastic prostatic epithelial cells and can promote epithelial proliferation in an autocrine manner. FGF17 expression is increased 2‐fold in BPH and may contribute to the increased epithelial proliferation seen in this disease. © 2004 Wiley‐Liss, Inc.
A stability guaranteed active fault‐tolerant control system against actuator failures
Authors: Maki Midori , Jiang Jin , Hagino Kojiro
Published: April 2004

In this paper, a new strategy for fault‐tolerant control system design has been proposed using multiple controllers. The design of such controllers is shown to be unique in the sense that the resulting control system neither suffers from the problem of conservativeness of conventional passive fault‐tolerant control nor from the risk of instability associated with active fault‐tolerant control in case that an incorrect fault detection and isolation decision is made. In other words, the stability of the closed‐loop system is always ensured regardless of the decision made by the fault detection and isolation scheme. A correct decision will further lead to optimal performance of the closed‐loop system. This paper deals with the conflicting requirements among stability, redundancy, and graceful degradation in performance for fault‐tolerant control systems by using robust control techniques. A detailed design procedure has been presented with consideration of parameter uncertainties. Both total and partial actuator failures have been considered. This new control strategy has been demonstrated by controlling a McDonnell F‐4C airplane in the lateral‐direction through simulation. Copyright © 2004 John Wiley & Sons, Ltd.
High levels of the mitochondrial large ribosomal subunit protein 40 prevent loss of mitochondrial DNA in null mmf1 Saccharomyces cerevisiae cells
Authors: Accardi Rosita , Oxelmark Ellinor , Jauniaux Nicolas , de Pinto Vito , Marchini Antonio , Tommasino Massimo
Published: April 2004

Members of the YERO57c/YJGFc/UK114 protein family have been identified in bacteria and eukaryotes. The budding yeast Saccharomyces cerevisiae contains two different proteins of this family, Hmf1p and Mmf1p. We have previously shown that Mmf1p is a mitochondrial protein functionally related to its human homologue and able to influence the maintenance of mitochondrial DNA. Deletion of Mmf1 results in loss of the mitochondrial genome. Using a multicopy suppression approach, we have identified a protein of the mitochondrial large ribosomal subunit, MRPL40, which stabilizes mtDNA in Δmmf1 cells. Overexpression of MRPL40 did not prevent loss of mtDNA in a mutant strain lacking the mitochondrial protein Abf2p. Thus, MRPL40 does not have a general effect on mtDNA stability, but it may be specific for the mmf1‐null strain. We also show that the Δmrpl40 cells present a similar phenotype to the mmf1‐null strain, having reduced mtDNA stability and growth rate. Furthermore, we observed that ρ+Δmrpl40 haploid cells can be obtained when tetrads are directly dissected on medium containing a non‐fermentable carbon source. Thus, replication and segregation of the mtDNA can occur in the absence of MRPL40. We also show that another mitochondrial ribosomal protein, MRPL38, is able to overcome the Δmmf1‐associated defect. Together, our results suggest a link between Mmf1p and the two mitochondrial ribosomal proteins. Copyright © 2004 John Wiley & Sons, Ltd.
Yeast involved in fermentation of Coffea arabica in East Africa determined by genotyping and by direct denaturating gradient gel electrophoresis
Authors: Masoud Wafa , Bjørg Cesar Lene , Jespersen Lene , Jakobsen Mogens
Published: April 2004

Samples of Coffea arabica were collected during the different stages of the fermentation from two production sites in Tanzania. The yeasts community was identified by genotyping using ITS–PCR and sequence analysis of the D1/D2 domain of the 26S rRNA gene. For confirmation, denaturating gradient gel electrophoresis (DGGE) of PCR‐amplified 26S rRNA gene was performed to detect yeast directly from coffee samples without cultivation. Yeast counts were in the range 4.0 × 104 − 5.0 × 107 CFU/g with an increase during fermentation. Three yeasts species were dominant. The predominant yeast found during fermentation and drying was Pichia kluyveri. Pichia anomala was found in high numbers during drying of coffee beans. Hanseniaspora uvarum was the predominant yeast during fermentation but decreased during drying. Kluyveromyces marxianus, Candida pseudointermedia, Issatchenkia orientalis, Pichia ohmeri and Torulaspora delbrueckii occurred in concentrations of 103 CFU/g or below in coffee samples. Saccharomyces cerevisiae and Candida xestobii were not isolated by cultivation, but by the DGGE technique. A good agreement was found between the sequence analysis of the D1/D2 domain of the 26S rRNA gene and sequencing of the DGGE bands. Sequences of yeast isolates determined in this study have been deposited in the GenBank database under Accession Nos AY305664–AY305669 and AY305672–AY305683. Sequences of DGGE bands have also been deposited in the GenBank database under Accession Nos AY314789–AY314802. Copyright © 2004 John Wiley & Sons, Ltd.
Candida glabrata Ste20 is involved in maintaining cell wall integrity and adaptation to hypertonic stress, and is required for wild‐type levels of virulence
Authors: Calcagno Ana‐Maria , Bignell Elaine , Rogers Thomas R. , Canedo Mariana , Mühlschlegel Fritz A. , Haynes Ken
Published: April 2004

The conserved family of fungal Ste20 p21‐activated serine‐threonine protein kinases regulate several signalling cascades. In Saccharomyces cerevisiae Ste20 is involved in pheromone signalling, invasive growth, the hypertonic stress response, cell wall integrity and binds Cdc42, a Rho‐like small GTP‐binding protein required for polarized morphogenesis. We have cloned the STE20 homologue from the fungal pathogen Candida glabrata and have shown that it is present in a single copy in the genome. Translation of the nucleotide sequence predicts that C. glabrata Ste20 contains a highly conserved p21‐activated serine–threonine protein kinase domain, a binding site for G‐protein β subunits and a regulatory Rho‐binding domain that enables the kinase to interact with Cdc42 and/or Rho‐like small GTPases. C. glabrata Ste20 has 53% identity and 58% predicted amino acid similarity to S. cerevisiae Ste20 and can complement both the nitrogen starvation‐induced filamentation and mating defects of S. cerevisiae ste20 mutants. Analysis of ste20 null and disrupted strains suggest that in C. glabrata Ste20 is required for a fully functional hypertonic stress response and intact cell wall integrity pathway. C. glabrata Ste20 is not required for nitrogen starvation‐induced filamentation. Survival analysis revealed that C. glabrata ste20 mutants, while still able to cause disease, are mildly attenuated for virulence compared to reconstituted STE20 cells. Copyright © 2004 John Wiley & Sons, Ltd.
The trehalose pathway and intracellular glucose phosphates as modulators of potassium transport and general cation homeostasis in yeast
Authors: Mulet Jose M. , Alejandro Santiago , Romero Carlos , Serrano Ramón
Published: April 2004

Trk, encoded by the partially redundant genes TRK1 and TRK2, is the major potassium transporter of Saccharomyces cerevisiae. This system is specific for potassium and rubidium but, by reducing the electrical membrane potential of the plasma membrane, Trk decreases the uptake of toxic cations such as lithium, calcium, aminoglycosides and polyamines, which are transported by other systems. Gain‐ and loss‐of‐function studies indicate that TPS1, a gene encoding trehalose‐6‐phosphate synthase and known to modulate glucose metabolism, activates Trk and reduces the sensitivity of yeast cells to many toxic cations. This effect is independent of known regulators of Trk, such as the Hal4 and Hal5 protein kinases and the protein phosphatase calcineurin. Mutants defective in isoform 2 of phosphoglucomutase (pgm2) and mutants defective in isoform 2 of hexokinase (hxk2) exhibit similar phenotypes of reduced Trk activity and increased sensitivity to toxic cations compared with tps1 mutants. In all cases Trk activity was positively correlated with levels of glucose phosphates (glc‐1‐P and glc‐6‐P). These results indicate that Tps1, like Pgm2 and Hxk2, increases the levels of glucose phosphates and suggest that these metabolites, directly or indirectly, activate Trk. Copyright © 2004 John Wiley & Sons, Ltd.
The use of Yarrowia lipolytica for the expression of human cytochrome P450 CYP1A1
Authors: Nthangeni M. B. , Urban P. , Pompon D. , Smit M. S. , Nicaud J.‐M.
Published: April 2004

Cytochromes P450 constitute a superfamily of haem‐thiolate mono‐oxygenases that are involved in the oxidative metabolism of lipophilic subtrates. These enzymes require association with cytochrome P450 reductase (CPR) to achieve optimal activities. We have expressed human cytochrome P450 CYP1A1 under the POX2 promoter (pPOX2–CYP1A1) in Y. lipolytica, with or without overproduction of Y. lipolytica CPR expressed under the ICL promoter (pICL–CPR) or the POX2 promoter (pPOX2–CPR). Activity of cytochrome CYP1A1 was analysed by conversion of hydroxyresorufin to resorufin. Strain JMY330 and JMY330–CPR present no activity, the monocopy cytochrome CYP1A1 integrant JMY331 and JMY331–CPR derivatives present an average activity of 32.0 pM/min/dw and 48.3 and 64.6 pM/min/dw for pICL–CPR and pPOX2–CPR, respectively. Increase of CPR expression resulted in about two‐fold higher activity. The multicopy 1A1 integrant JMY339 and JMY339–CPR derivatives present an activity of 129 pM/min/dw and 815–1845 pM/min/dw, respectively. Increase of CPR expression resulted in 6.3–12.8‐fold higher activity, depending on the CPR transformant. We observed a 50‐fold increase of activity between the monocopy integrant JMY331 as compared to the multicopies integrant JMY339–CPR in which CPR was overexpressed. Copyright © 2004 John Wiley & Sons, Ltd.
Transcriptional and post‐translational regulation of neutral trehalase in Schizosaccharomyces pombe during thermal stress
Authors: Paredes Vanessa , Franco Alejandro , Madrid Marisa , Soto Teresa , Vicente‐Soler Jero , Gacto Mariano , Cansado José
Published: April 2004

In the fission yeast Schizosaccharomyces pombe, a heat shock enhances transcription of the ntp1+ gene, encoding the hydrolytic enzyme neutral trehalase. As compared to wild‐type cells, cells devoid of the MAP kinase Sty1p showed a strong decrease in ntp1+ expression induced by the temperature upshift, indicating that the stress‐activated protein kinase (SAPK) pathway regulates the expression of this gene during heat shock. The transcription factor Atf1p, which is the main downstream target for Sty1p in the SAPK pathway, appears to be involved in such control, since ntp1+ expression under heat shock proved to be significantly blocked in atf1+‐disrupted cells. Serial deletion and point mutation analyses of the ntp1+ promoter, as well as electrophoretic mobility shift assays, revealed the existence of a CRE‐like element as the target for Atf1p‐mediated expression under thermal stress. The relevance of two putative HSE elements located in the ntp1+ promoter was also investigated for their potential role in regulating ntp1+ transcription during heat shock. The results support a model in which heat‐induced Atf1p binding to the CRE‐like element favours the subsequent interaction of the heat shock factor (HSF) with HSE elements in the ntp1+ promoter. Unlike what happens under osmostress or oxidative treatments, Sty1p has no role in the post‐translational activation of neutral trehalase induced by heat shock in the fission yeast. Copyright © 2004 John Wiley & Sons, Ltd.
Lines of arrested growth in bone and age estimation in a small primate: Microcebus murinus
Authors: Castanet J. , Croci S. , Aujard F. , Perret M. , Cubo J. , de Margerie E.
Published: April 2004

In primates, age determination using lines of arrested growth (LAGs) from bones has rarely been attempted, and the reliability of these structures has never been experimentally validated. In order to test skeletochronology in primates, LAGs were studied mainly in the long bones of known age Microcebus murinus, a small primate, whose potential longevity may reach 12 years. LAGs were extensively studied in 43 males and 23 females ranging from juveniles to 11‐year‐old adults. All individuals were born and reared in captivity. Some young individuals were injected with fluorescent dyes to quantify bone growth rates. LAGs in the diaphysis of the tibia are well correlated with age and this skeletal element appears to be the best for assessing skeletochronology in Microcebus murinus. There is strong evidence that the seasonal cycle of photoperiodicity is more important than age alone in producing LAGs.
Ecomorphological indicators of feeding behaviour in the bears (Carnivora: Ursidae)
Authors: Sacco Tyson , Van Valkenburgh Blaire
Published: April 2004

Patterns of morphological variation in the skulls of extant bears were studied as they relate to diet and feeding behaviour. Measurements of craniodental features were used to compute indices that reflect dietary adaptations of the dentition and biomechanical properties of the skull, jaw and related musculature. Species were classified as either carnivores, omnivores, herbivores or insectivores. Differences among dietary groups were assessed with analysis of variance and discriminant factor analysis. Results demonstrated significant morphological separation among all four groups. Carnivores were distinguished by, among other features, molar size reduction, flexible mandibles and, most surprisingly, relatively small carnassial blades. In contrast, herbivores displayed, among other features, large molar grinding areas, rigid mandibles and large carnassial blades. The insectivorous sloth bear was characterized by extreme reduction of the post‐canine teeth. As expected, omnivores tended to have morphology intermediate between that of carnivorous and herbivorous ursids. Comparison with previous studies revealed that bears exhibit a different set of morphological specializations for diet than other carnivoran groups. Carnivorous ursids, for example, were found to share aspects of craniodental morphology with omnivorous canids. The relatively weak adaptations for carnivory observed in bears may be the result of selection for the ability to cope with temporal fluctuations in dietary components. The giant pandaAiluropoda melanoleucawas found to have a relatively stiff jaw and great mechanical advantage of the jaw‐closing muscles, features previously observed in carnivorous canids and unexpected in this herbivorous bear. Comparison of patterns of morphological variation and patterns of phylogenetic relationships among species revealed surprisingly strong congruence between morphology and phylogenetics.
Apparent movement in a visual display: the ‘passing cloud’ of Octopus cyanea (Mollusca: Cephalopoda)
Authors: Mather Jennifer A. , Mather D. Lynn
Published: April 2004

The tremendous capacity of the chromatophore system in cephalopod skin to change its colour across space and time has allowed these animals to produce complex visual displays to conspecific and heterospecific targets, including the aptly‐named ‘passing cloud’. This display has been suggested as an interspecies communication, but it has not been investigated in detail. Octopus cyanea produced dark passing clouds during hunting of crab prey, typically after a web‐over capture attempt. Clouds moved not randomly but forward along the mantle, over the head and down the outstretched arm web, and were often accompanied by white margins that enhanced their appearance by intensity contrast. This visual display is presumed to be a startle attempt, producing apparent movement by selective sequential chromatophore expansion to induce a crab to move without the drawback of motion by the octopus itself.
A typology of historiae in West Francia (8–10 c.)
Authors: GOUDESENNE JEAN-FRANÇOIS
Published: April 2004

This article presents a typology for a large corpus of Proper Offices from the former Francia occidentalis, composed before the year 1000. A threefold classification for these historiae will be proposed: (1) the Carolingian basilical Office (8–9 c.); (2) Offices organized in modal order (after 900); and (3) Offices composed around the year 1000. The methodology established for this hitherto unpublished, not widely known repertory will permit certain conclusions to be drawn. For example, some Offices have historical importance either because of their age or because of the evolution of the style of melodic composition which they imply, or because they belong to a hagiographic output significant in the history of Carolingian texts. These historiae suppose the literary participation of well-known authors like Hilduin of St Denis, Hincmar of Rheims or Milo and Hucbald of St Amand, thus inviting us to rethink attribution criteria applicable to these historiae. I propose to focus essentially on the written transmission of the repertory in Western sources of plainchant. This transmission is characterized by a series of continuities and disruptions in the process of diffusion and exchanges among basilicas, monasteries and cathedrals of Carolingian and post-Carolingian Francia. The reworking of hagiographic texts suggests a model applicable to the rewriting process found in musical compositions.
Paved with good intentions: the dynamic effects of WTO review of anti-dumping action
Authors: TARULLO DANIEL K.
Published: April 2004

Virtually every national trade remedy measure challenged in WTO dispute settlement has resulted in at least partial victory for the exporting country. In the anti-dumping area, the special standard of review for national interpretations of Anti-Dumping agreement obligations has had little discernible effect on dispute settlement outcomes. This pattern, while applauded by some as promoting liberal trade values, may actually result in less trade liberalization. If important trading countries like the United States believe that the Appellate Body will undermine provisions intended to preserve their ability to use trade remedies, they may decline to negotiate further disciplines on the use of these remedies or, possibly, to enter multilateral negotiations entirely. Although insufficient information exists to reach definitive conclusions, recent developments suggest that such negative effects are occurring in the Doha Round.
Air‐sea interaction and feasibility of tsunami detection in the open ocean
Authors: Godin Oleg A.
Published: April 2004

Recent observations of “tsunami shadows,” i.e., extended darker strips on the ocean surface along a front of a weak tsunami off Oahu, Hawaii, suggest that tsunamis in the deep ocean may be remotely detected through changes in ocean surface roughness. In this paper, physical mechanisms responsible for the formation of “tsunami shadows” are considered. The hypothesis that the change in surface roughness is due to an air‐sea interaction is examined. Using an eddy‐viscosity model for the average Reynolds stresses in turbulent flow, a theory is developed to model tsunami‐induced perturbations in the atmospheric boundary layer. It is demonstrated that in the lowest tens of centimeters of the atmosphere, tsunami‐induced perturbations of the mean wind velocity are much greater than current velocities in the water and can be comparable to the unperturbed wind velocity. Enhancement of tsunami‐induced wind velocity perturbations compared to currents in the tsunami wave occurs because of a generation of a viscous wave in the air by a coherent elevation of large expanses of the ocean surface in the tsunami wave. The ratio of the maximum wind velocity perturbation to the amplitude of the current velocity approximately equals (πD/4κ2λ) ln2 (κu*λ/2πcz0), where κ is the von Kármán constant, u* is the friction velocity of a background wind, z0 is the roughness length of the ocean surface, D is ocean depth, and λ and c are the tsunami wavelength and velocity, respectively. The results are shown to be robust with respect to a choice of a closure model for Reynolds stresses. Dependence of the tsunami‐induced atmospheric perturbations on background wind velocity and direction, tsunami period and amplitude, and ocean depth is studied. Implications of the theoretical predictions on the feasibility of a satellite‐based system relying on radars and/or microwave radiometers for early tsunami warning are discussed.
Viscous fingering instabilities in an oil in water emulsion
Authors: Kawaguchi Masami , Yamazaki Sayaka , Yonekura Kenji , Kato Tadaya
Published: April 2004

Viscous fingering of an emulsion in which silicone oil is dispersed in aqueous polymer solution was investigated in a radial Hele-Shaw cell by the injection of water and the aqueous polymer solution as a function of the injection rate. The pressure imposed at the finger tip was simultaneously monitored. The crack-like fingering patterns are observed at the lower injection rates and they start to grow when the imposed pressure attains the maximum value. An increase in the injection rate causes the pattern transition from the crack pattern to ramified ones. Such a pattern transition is strongly related to rheological properties of the emulsion.
Standard-deviation minimization for calibrating the radii of spheres attached to atomic force microscope cantilevers
Authors: Thoreson E. J. , Burnham N. A.
Published: April 2004

We describe an efficient method for determining the radii of spheres attached to atomic force microscope (AFM) cantilevers by minimizing the square root of the square error for a segment of circular arc cross-sectional data. The approach we present has benefits: (1) The method fits a function, with two fitting parameters, to a number of data points, rather than calculating the radius based on two points of cross-sectional data, (2) a fit is performed in a common spreadsheet application, using a solving feature, and (3) spheres of diameters 2 to 60 μm were measured to an accuracy of 9% and a precision of 4%.
Impedance measurements and modeling of a transition-edge-sensor calorimeter
Authors: Lindeman Mark A. , Bandler Simon , Brekosky Regis P. , Chervenak James A. , Figueroa-Feliciano Enectali , Finkbeiner Fred M. , Li Mary J. , Kilbourne Caroline A.
Published: April 2004

We describe a method for measuring the complex impedance of transition-edge-sensor (TES) calorimeters. Using this technique, we measured the impedance of a Mo/Au superconducting transition-edge-sensor calorimeter. The impedance data are in good agreement with our linear calorimeter model. From these measurements, we obtained measurements of unprecedented accuracy of the heat capacity and the gradient of resistance with respect to temperature and current of a TES calorimeter throughout the phase transition. The measurements probe the internal state of the superconductor in the phase transition and are useful for characterizing the calorimeter.
Electronic noise in a constant voltage anemometer
Authors: Weiss Julien , Comte-Bellot Geneviève
Published: April 2004

The electronic noise and the signal-to-noise ratio in a constant voltage anemometer (CVA) are analyzed in terms of the main constitutive elements of the circuit. It is shown that the output voltage due to electronic noise decreases with the wire resistance, permitting one to know the noise upper limit by using the results of the unheated wire. The noise power spectrum increases at high frequencies as f2, like in other anemometers, because of the need to compensate for the thermal lag of the hot wire, thus leading to a reduced signal-to-noise ratio at high frequencies. Explicit formulas are given in terms of wire, CVA, and flow quantities. Measurements of electronic noise in a CVA prototype confirm the theoretical analysis and illustrate some interesting issues concerning measurements of noise and low levels of flow fluctuations.
Strain-independent temperature measurement using a type-I and type-IIA optical fiber Bragg grating combination
Authors: Pal Suchandan , Sun Tong , Grattan Kenneth T. V. , Wade Scott A. , Collins Stephen F. , Baxter Gregory W. , Dussardier Bernard , Monnom Gérard
Published: April 2004

A simple and effective technique for strain-independent temperature measurement has been demonstrated using the peak wavelengths of both type-I and type-IIA fiber Bragg gratings written without hydrogen loading in the same fiber, this having been specially fabricated with a high concentration of germanium in the core composition. The device is also capable of monitoring strain and temperature simultaneously and can be used to measure temperature over the range of 25–300 °C with a strain range of 0–500 με, achieving a temperature-dependent sensitivity of 0.53 and 0.31 pm/°C for strain-independent temperature measurement with root mean square errors of 2.4 and 4.1 °C at 25 and 300 °C, respectively.
Spatial distribution of the light emitted by an excimer lamp used for ultraviolet-B photo-therapy: Experiment and modeling
Authors: Di Lazzaro P. , Murra D. , Felici G. , Fu S.
Published: April 2004

The availability of excimer lamps, which emit ultraviolet (UV) noncoherent but narrow-bandwidth radiation, allowed a drastic reduction of the costs of the UV photo-therapy that has so far been accomplished by using excimer lasers. The main goal of this work is the measurement of the spatial distribution of the radiation intensity emitted by a commercial excimer lamp, to check the uniformity of the dose delivered to the target when changing either the distance from the lamp or the surface to be irradiated. The results show that a good uniformity of the delivered dose is achieved within a limited area and that when changing by only 1 cm the distance between the lamp and the target, the dose delivered to the target noticeably changes its value. The experimental data are in good agreement with the analytical results achieved by approximating the lamp by a uniform two-dimensional source.
Micromachined ultrasonic droplet generator based on a liquid horn structure
Authors: Meacham J. M. , Ejimofor C. , Kumar S. , Degertekin F. L. , Fedorov A. G.
Published: April 2004

A micromachined ultrasonic droplet generator is developed and demonstrated for drop-on-demand fluid atomization. The droplet generator comprises a bulk ceramic piezoelectric transducer for ultrasound generation, a reservoir for the ejection fluid, and a silicon micromachined liquid horn structure as the nozzle. The nozzles are formed using a simple batch microfabrication process that involves wet etching of (100) silicon in potassium hydroxide solution. Device operation is demonstrated by droplet ejection of water through 30 μm orifices at 1.49 and 2.30 MHz. The finite-element simulations of the acoustic fields in the cavity and electrical impedance of the device are in agreement with the measurements and indicate that the device utilizes cavity resonances in the 1–5 MHz range in conjunction with acoustic wave focusing by the pyramidally shaped nozzles to achieve low power operation.
Numerical analysis of the shear flow of a binary mixture of hard-sphere gases over a plane wall
Authors: Yasuda Shugo , Takata Shigeru , Aoki Kazuo
Published: April 2004

The shear flow of a binary mixture of rarefied gases over a plane wall is investigated on the basis of the linearized Boltzmann equation for hard-sphere molecules with the diffuse reflection boundary condition. This fundamental problem in rarefied gas dynamics is analyzed numerically by a finite-difference method, in which the complicated collision integrals are computed by the extension to the case of a gas mixture of the method proposed by Sone, Ohwada, and Aoki [Phys. Fluids A 1, 363 (1989)]. As a result, the behavior of the mixture is clarified not only at the level of the macroscopic variables but also at the level of the velocity distribution function. In addition, an accurate formula of the shear-slip (viscous-slip) coefficient for arbitrary values of the concentration of a component gas is constructed by the use of the Chebyshev polynomial approximation.
Effects of surface roughness and freestream turbulence on the wake turbulence structure of a symmetric airfoil
Authors: Zhang Qiang , Lee Sang Woo , Ligrani Phillip M.
Published: April 2004

The effects of surface roughness on the wake characteristics of a simulated turbine airfoil, operating in a compressible, high-speed environment, are studied at different freestream turbulence levels. The effects of these parameters on wake distributions of mean velocity, turbulence intensity, and turbulence length scale, as well as on power spectral density profiles and vortex shedding frequencies are quantified one chord length downstream of airfoil. All profile quantities broaden considerably, with lower peak values, as either the level of surface roughness of the turbulence intensity increases. Non-dimensional vortex shedding frequencies also decrease as either the level of surface roughness or the turbulence intensity increases.
Yield of wheat and canola in the high rainfall zone of south-western Australia in years with and without a transient perched water table
Authors: Zhang Heping , Turner Neil C. , Poole Michael L.
Published: April 2004

The yields of wheat and canola in 2 successive years with and without the development of a perched watertable were compared in the high rainfall zone of south-western Australia. In 2001, no perched watertable was observed and wheat and canola yields were close to their estimated potentials. In 2002, a perched watertable developed at less than 30 cm below the soil surface for more than 8 days and at less than 50 cm below the soil surface for at least 30 days at the tillering stage of wheat and at the rosette stage of canola. The air-filled porosity of the soil fell below the critical value of 10% at 10 and 30 cm depth for about 40 days. This reduced the maximum leaf area index of canola by 46% and of wheat by 30%, and reduced the shoot dry matter of wheat at flowering by 27% and by 40% at podding in canola compared with those in 2001. The growth of the wheat roots was constrained at depths from 50-90 cm from the soil surface in 2002 compared with 2001. However, the roots of canola and wheat were able to grow to at least 1.4 m in both 2001 and 2002. In both years, a much higher proportion (>10%) of roots was present in the clay subsoil compared with previous reports in south-western Australia and enabled the crops to utilise a greater amount of water from the clay subsoil. The wheat yield in 2002 was 37% lower than in 2001 and well below the potential, largely as a result of a reduced tiller number per plant and ears per unit area. Despite the greater reduction in dry matter in canola than in wheat in 2002, the seed yield of canola was 17% higher in 2002 than in 2001. Canola, an indeterminate crop, was able to respond to the late rain that occurred in 2002 compared with 2001 and produced a significantly higher seed number per unit area. In 2002, grain size in wheat was 25% larger than in 2001, but this increase was insufficient to compensate for the yield loss resulting from the fewer ears per unit area. It is concluded that early transient perched watertable induced subsurface waterlogging, and that the subsurface waterlogging can be a major constraint to crop growth in the high rainfall region of southwestern Australia, and that reducing waterlogging could be a key to achieving higher crop production.