bluuebunny/crossref_metadata_2025 huggingface dataset:
Unique proximal tibial morphology in strepsirrhine primates
Authors: White Jessica L. , Gebo Daniel L.
Published: November 2004

Although the morphology of the tibial plateau in primates has received very little attention in the literature, it does exhibit features of phylogenetic and functional interest. This paper describes the morphology of the tibial plateau (particularly the intercondylar region) in extant and fossil primates, and in three mammalian outgroups: the pen‐tailed tree shrew (Ptilocercus), tree shrew (Tupaia), and flying lemur or dermopteran (Cynocephalus). Extant and fossil strepsirrhine primates exhibit an eminence with a single spine, which contrasts with the intercondylar morphology of haplorhine primates. Most extant platyrrhines, all catarrhine primates (including humans), and some fossil haplorhines possess an eminence with two spines (medial and lateral) connected by a ridge of bone that intersects the intercondylar groove. Tarsius and callitrichines possess an eminence with a reduced medial spine that superficially resembles that of strepsirrhine primates. Dermopterans also exhibit a morphology similar to that of strepsirrhines. In Scandentia, the intercondylar morphology of Tupaia is similar to that of rodents, whereas Ptilocercus resembles tarsiers and callitrichines. We hypothesize that proximal tibiae with either a single spine or reduced medial spine morphology facilitate a greater degree of knee rotation about the eminence relative to the double‐spine condition, and are likely associated with more frequent adoption of vertical body positions. In contrast, a double‐spine eminence limits knee rotation and is probably associated with greater use of horizontal supports. Although the polarity is complicated by the unknown phylogenetic status of likely sister taxa, it seems most probable that the single‐spine morphology is a derived feature of strepsirrhines. Am. J. Primatol. 64:293–308, 2004. © 2004 Wiley‐Liss, Inc.
Improved Reaction and Activation Energies of [4+2] Cycloadditions, [3,3] Sigmatropic Rearrangements and Electrocyclizations with the Spin‐Component‐Scaled MP2 Method
Authors: Goumans T. P. M. , Ehlers Andreas W. , Lammertsma Koop , Würthwein Ernst‐Ulrich , Grimme Stefan
Published: November 2004

A new quantum mechanical scheme to calculate electronic correlation energies, spin‐component‐scaled MP2, was tested as a tool to predict reaction energies and barriers in computational organic chemistry. Three common pericyclic reactions with known unsatisfactory MP2 descriptions were reinvestigated with the modified MP2 approach, in which the parallel and anti‐parallel spin components of the correlation energy are scaled separately. The SCS‐MP2 calculated reaction and activation energies of nine Diels–Alder reactions, four [3,3] sigmatropic rearrangements, and ten electrocyclization reactions are compared to those of the MP2, B3 LYP, QCISD(T), and G3 methods. For each, the SCS‐MP2 results are in excellent agreement with the experimental data and compare far more favorably to G3 than both MP2 and B3 LYP. Careful evaluation of the effect of the size of the atomic orbital (AO) basis set shows that the larger expansions improve the agreement with experiment for the SCS‐MP2 method, while they get worse for both MP2 and B3 LYP.
Self‐Assembly of Folic Acid Derivatives: Induction of Supramolecular Chirality by Hierarchical Chiral Structures
Authors: Kamikawa Yuko , Nishii Masayuki , Kato Takashi
Published: November 2004

Hierarchical chiral structures made up of dendritic oligo(L‐ or D‐glutamic acid) moieties of folic acid derivatives induce supramolecular chirality in the self‐assembled columnar structures of the folic acids. These folic acids self‐assemble through the intermolecular hydrogen bonds of the pterin rings to form disklike tetramers. In the neat states, the stacked tetramers form thermotropic hexagonal columnar phases over wide temperature ranges, including room temperature. Addition of alkali metal salts induces chirality in the columnar phases. In dilute solution states in a relatively polar solvent (chloroform), the folic acid derivatives form non‐chiral, self‐assembled structures. In the presence of sodium triflate, the folic acid forms chiral columnar assemblies through the oligo(L‐glutamic acid) moiety, similar to those formed in the liquid‐crystalline (LC) states. The enantiomer of the folic acid induces columnar assemblies with reversed helicity. In the case of the diastereomer, no induced helicity is observed. Application of an apolar solvent (dodecane) drives the folic acid derivatives to form chiral assemblies in the absence of ions. In this case, lipophilic interactions promote nanophase segregation, which enhances the formation of chiral columns. Interestingly, the chiral supramolecular structure of the diastereomer induces the most intense circular dichroism. In both cases, the molecular chirality in the oligo(glutamate) moieties yields supramolecular chirality of the folic acids that self‐assemble through cooperative molecular interactions.
Intramolecular Rearrangement for Regioselective Complexation by Intramolecular CH/π Interaction in a Hydrophobic Cavity of a Ruthenium Coordination Sphere
Authors: Kojima Takahiko , Miyazaki Soushi , Hayashi Ken‐ichi , Shimazaki Yuichi , Tani Fumito , Naruta Yoshinori , Matsuda Yoshihisa
Published: November 2004

A RuII complex with a hydrophobic cavity formed from two 1‐naphthoylamide groups was prepared. Its reactions with β‐diketones gave β‐diketonato complexes in which hydrophobic π–π or CH/π interactions were confirmed by NMR spectroscopy and X‐ray crystallography. In the case of the asymmetric β‐diketone benzoylacetone, an isomer with a CH/π interaction was afforded as the sole product owing to thermodynamic control. The reaction was found to involve a novel intramolecular rearrangement from the phenyl‐included isomer to the methyl‐included one without rupture of Ruβ‐diketonato coordination bonds (activation energy 52 kJ mol−1). This indicates that CH/π interactions can be more favored thermodynamically than π–π interactions in a suitable hydrophobic environment.
Thromboembolic events with estramustine phosphate‐based chemotherapy in patients with hormone‐refractory prostate carcinoma
Authors: Lubiniecki Gregory M. , Berlin Jesse A. , Weinstein Rachel B. , Vaughn David J.
Published: November 2004

BACKGROUND

Combinations of cytotoxic chemotherapy with estramustine phosphate (EMP), a nornitrogen mustard‐estrogen conjugate, are used to treat patients with hormone‐refractory prostate carcinoma (HRPC). However, thromboembolic events (TE), including deep venous thrombosis (DVT), pulmonary embolism, stroke, myocardial infarction, and arterial thrombosis, are significant toxicities of these regimens. The current study sought to establish the rate of TE and to determine risk factors for TE.

METHODS

A MEDLINE‐based search identified EMP‐based clinical trials published in the English‐language peer‐reviewed literature after 1990 in which ≥ 20 patients with HRPC were enrolled and TE were clearly documented. Patient characteristics and the dose of EMP given were analyzed to determine their association with the rate of TE.

RESULTS

Twenty‐three studies, enrolling a total of 896 patients, were included in the analysis. The overall risk of TE was 0.07 (95% confidence interval [95% CI], 0.05–0.11). The risk of DVT was 0.06 (95% CI, 0.04–0.09). The risks of all other types of TE were < 0.01. Using univariate logistic regression analysis, the dose of EMP administered, baseline patient age, and baseline prostate‐specific antigen level were not found to be associated with the total risk of TE. The rates of total TE and DVT may be inflated because one of the analyzed studies initially had a very high rate of DVT (25%) when compared with the others.

CONCLUSIONS

The rate of TE in men with HRPC who are treated with EMP‐based regimens is significant, but it does not appear to be related to the dose of EMP. Whether TE can be prevented with anticoagulant prophylaxis remains to be determined. Cancer 2004. © 2004 American Cancer Society.
Impact of functional support on health‐related quality of life in patients with colorectal cancer
Authors: Sultan Shahnaz , Fisher Deborah A. , Voils Corrine I. , Kinney Anita Y. , Sandler Robert S. , Provenzale Dawn
Published: November 2004

BACKGROUND

It has been shown that social integration and the availability of social support influence quality of life. However, little is known about the relation between social support and mental and physical health in patients with colorectal cancer. In the current study, the authors examined the effects of social network size, as well as emotional and instrumental support, on health‐related quality of life (HRQOL) in patients with colorectal cancer.

METHODS

Six hundred thirty‐six veterans with colorectal cancer were asked to complete a telephone interview, which included a measure of social support (the Berkman–Syme Index) and the Medical Outcomes Study Short Form 12‐Item Survey. Mean physical composite scale (PCS) and mental composite scale (MCS) scores were compared across groups.

RESULTS

No difference in mean PCS or MCS scores was found between patients who had larger social networks and patients who had smaller social networks. The availability of emotional and instrumental support was associated with higher MCS scores, whereas the availability of instrumental support was associated with lower PCS scores.

CONCLUSIONS

Irrespective of network size, the availability of emotional support and instrumental support had an impact on HRQOL in patients with colorectal cancer. More emphasis needs to be placed on understanding how various types of social support, individually and collectively, influence physical and mental health in patients with colorectal cancer. Cancer 2004. © 2004 American Cancer Society.
Der Reis und das Wasser
Authors: Sattelmacher Burkhard , Dittert Klaus , Lin Shan
Published: November 2004

In Asien wird die Hälfte der Wasserressourcen für den Reisanbau benötigt. In einem neuen Verfahren wird ein wassersparendes Anbausystem erprobt
Spermien auf duftenden Spuren
Authors: Hatt Hanns , Spehr Marc
Published: November 2004

Nachrichten aus der Welt der Düfte: Auch menschliche Spermien können riechen. Deshalb spielen chemische Duftnoten bei der Fortpflanzung eine große Rolle
Messungen im Magnetfeld
Authors: Bauer Wolfgang
Published: November 2004

Um die Durchblutung des menschlichen Herzmuskels besser sichtbar zu machen, setzen Mediziner auf die neuen Möglichkeiten der Kernspin‐Tomographie
Wenn die biologische Pumpe gestört wird
Authors: Eickhoff Susanne , Ittekkot Venugopalan , Jennerjahn Tim
Published: November 2004

Weltweit unterbrechen rund 45 000 Staudämme den natürlichen Abfluss des Wassers in die Ozeane. Dadurch wird der Siliziumkreislauf empfindlich beeinträchtigt, das ökologische Gleichgewicht gerät in Gefahr
UV‐crosslinking of E1 small nucleolar RNA to proteins in frog oocytes
Authors: Smith James L. , Walton Andrew H. , Eliceiri George L.
Published: November 2004

E1/U17 small nucleolar RNA (snoRNA) is a box H/ACA snoRNA. To detect protein bands that UV‐crosslink to E1 RNA primarily at uridines, frog oocytes were injected with [α‐32P]UTP‐labeled E1 RNA and incubated, isolated nuclei were UV irradiated, and nuclear contents were digested with RNase A. Wild‐type E1 RNA specifically UV‐crosslinked to several protein bands. To identify E1 RNA sites involved in these interactions, we tested 21 E1 RNA mutants, each consisting of substitutions in a conserved sequence or structure. UV‐crosslinking of different protein bands to E1 RNA depended on one of the following sets of conserved E1 RNA segments: two 5′ end RNA sites; five 5′ half RNA sites; two 3′ half RNA sites; or 14 sites located throughout E1 RNA. Of these conserved E1 RNA sites, UV‐crosslinking apparently depended on sequences at 11 sites, and structures at 2 sites. Gel electrophoresis with and without RNA competition detected protein bands that are not common to all of the box H/ACA snoRNAs. © 2004 Wiley‐Liss, Inc.
Development and characterization of a cell line for large‐scale, serum‐free production of recombinant adeno‐associated viral vectors
Authors: Farson Deborah , Harding Thomas C. , Tao Lucy , Liu Jun , Powell Sandra , Vimal Vishalini , Yendluri Satyasri , Koprivnikar Kathryn , Ho Kenneth , Twitty Christopher , Husak Paul , Lin Andy , Snyder Richard O. , Donahue Brian A.
Published: November 2004

Background

One of the major limitations to the use of adeno‐associated virus (AAV) vectors for gene therapy has been the difficulty in producing enough vector to supply a clinical trial. More than 20 000 roller bottles may be required to generate AAV by the traditional transient transfection process to treat 50 patients. A scalable AAV producer cell line grown in serum‐free media will meet the needs for the manufacture of AAV gene therapeutics.

Methods

A packaging cell line was generated by introducing the AAV rep and cap genes into A549 cells. From this packaging cell line, a number of producer cell lines were generated by infecting the packaging cell with the appropriate AAV vector. Producer cell lines were then adapted to serum‐free suspension conditions for growth in bioreactors.

Results

We report here the development of six AAV producer cell lines that generate > 104 particles/cell. The rAAV vector preparations from these cell lines have physical and functional characteristics similar to rAAV vectors prepared by transient transfection. To enable large‐scale production, producer cell lines were adapted to serum‐free suspension and we demonstrate production of AAV at the 15 L scale. In addition, vector preparations from these cell lines were shown to be free of wild‐type AAV.

Conclusions

AAV producer cell lines can be readily scaled to meet the needs of clinical trials. One 500 L bioreactor of these producer cells can produce the equivalent of 2500 high capacity roller bottles or 25 000 T‐175 tissue culture flasks. Copyright © 2004 John Wiley & Sons, Ltd.
Helical Poly(3‐methyl‐4‐vinylpyridine)/Amino Acid Complexes: Preparation, Characterization, and Biocompatibility
Authors: Sannigrahi Biswajit , McGeady Paul , Khan Ishrat M.
Published: November 2004

Summary: Helical poly(3‐methyl‐4‐vinylpyridine) (P3M4VP)/amino acid complexes have been prepared via acid‐base reaction of the achiral polymer with D and L amino acids: alanine, leucine, valine, serine and phenylalanine. The circular dichroism (CD) spectra of P3M4VP/D‐ and L‐alanine complexes in CH3OH/H2O show opposing (near mirror image) Cotton effect signals at 278.4, 274.8 and 270.8 nm, indicating the formation of enantiomeric secondary structures. The formation of the enantiomeric structures is supported by observed [α] values of −3.0 and +3.0 for the P3M4VP/D‐alanine and P3M4VP/L‐alanine complexes, respectively. The preparation of helical P3M4VP/amino acid complexes has been carried out in CH3OH and H2O at pH 1.8 and 2.7. The intensities of the Cotton effect signals were good. For example, for the P3M4VP/L‐alanine complexes in CH3OH/H2O and H2O (pH 1.8), the second Cotton effect signal around 275–277 nm show [θ] values of 49 980 and 79 210 deg · cm2 · dmol−1, respectively. The formation of the helical secondary structure is rapid. The acid‐base reaction between P3M4VP and L‐alanine in CH3OH/H2O, in 10 min, show a CD spectrum with Cotton effect signals at 274 and 272 nm with [θ] values of 27 000 deg · cm2 · dmol−1 and −36 000 deg · cm2 · dmol−1, respectively. P3M4VP permits ready conformational reorientation on complexation with amino acids, but once the helical P3M4VP/amino acid complexes are formed, it is stable at room temperature. P3M4VP is not compatible with HeLa ovarian cancer cells, but the helical P3M4VP/amino acid complexes are compatible with HeLa cells. The complexes minimally interfere with the adhesion and growth of HeLa cells on complex surfaces.

Helical poly(3‐methyl‐4‐vinylpyridine)/D‐ and L‐alanine complexes support the attachment and growth of HeLa cells. The micrographs shows HeLa cells after three days: left panel: on P3M4VP/L‐alanine complex; right panel: on P3M4VP/D‐alanine complex.

magnified image

Helical poly(3‐methyl‐4‐vinylpyridine)/D‐ and L‐alanine complexes support the attachment and growth of HeLa cells. The micrographs shows HeLa cells after three days: left panel: on P3M4VP/L‐alanine complex; right panel: on P3M4VP/D‐alanine complex.
Numerical approximation of two‐dimensional convection‐diffusion equations with boundary layers
Authors: Jung Chang‐Yeol
Published: November 2004

Our aim in this article is to show how one can improve the numerical solution of singularity perturbed problems involving boundary layers. Incorporating the structures of boundary layers into finite element spaces can improve the accuracy of approximate solutions and result in significant simplifications. In this article we discuss convection‐diffusion equations in the two‐dimensional space with a homogeneous Dirichlet boundary condition and a mixed boundary condition. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Structure and mechanical properties of poly(sulfone of bisphenol A)/poly(butylene terephthalate) blends
Authors: Retolaza A , Eguiazábal JI , Nazábal J
Published: November 2004

Blends of poly(sulfone of bisphenol A) (PSU) with poly(butylene terephthalate) (PBT) were obtained by direct injection moulding across the composition range. The two components of the blends reacted slightly in the melt state, producing linear copolymers. The slight changes observed in the two glass transition temperatures indicate that the copolymers were present in the two amorphous phases of the blends. The observed reactions and the high viscosity of the matrix of the PSU‐rich compositions led to a very fine morphology which could not be attained in the PBT‐rich compositions due to the low viscosity of the matrix and the direct injection moulding procedure used. This procedure is fast and economically advantageous, but leads to poor mixing. The different morphologies influenced neither the modulus nor the yield stress, which tended to follow the rule of mixtures. However, the low fracture properties of the PBT‐rich compositions contrasted with the ductility behaviour, and even the impact strength of the PSU‐rich blends, which also tended to be proportional to the blend composition. Copyright © 2004 Society of Chemical Industry
On Applicability of a Direct Shear Test for Strength Estimation of Cereal Grain
Authors: Molenda Marek , Horabik Józef
Published: November 2004

Investigations were performed to verify the applicability of a direct shear method as recommended by Eurocode 1 for testing the strength of cereal grains [2]. Tests on rye without preconsolidation have shown that stress‐strain characteristics depend on the method of sample deposition. However, consolidation of the sample by twisting the top plate, as recommended by the code, neutralizes the influence of the grain packing structure on values of the angle of internal friction. Determination of the strength parameters for grain of six genera, under normal reference pressure of 100 kPa, and five levels of moisture content in a range from 10% to 20%, confirmed the applicability of the test. The only necessary modification of Eurocode procedure was elongation of the shear path up to the 0.1 ΔL/D level of the sample diameter. Values for the angle of internal friction were found to range from 22.1°–35.5° and were dependent on the grain genus and moisture content. The majority of dry grain samples showed low cohesion (below 4 kPa), and thus, should be treated as free flowing material. The increase in moisture content resulted in an increase of cohesion up to the highest observed value of 12 kPa. Triaxial compression tests were performed on wheat of five levels of moisture content, and gave results that were in close agreement with the results of the direct shear test.
The Reclaim Screw in Mammoth Silos Operating on a Free Surface: Comparison Between Horizontal and Inclined Operation on Free Flowing Bulk Solids
Authors: Oosterhuis Ekke , Schott Dingena , van Wijk Arjen
Published: November 2004

Although the screw conveyor, operating on a free surface, has been used for years as reclaim and storage equipment in mammoth silos, there is no documented knowledge about its spill characteristics. Research at Delft University of Technology together with ESI Eurosilo B.V. on the inclined use of the reclaim screw to achieve homogenization in mammoth silos made this lack of knowledge apparent. This paper presents the results of experiments to gain insight into the spill during reclaiming. Experiments were conducted reclaiming a horizontal surface and up‐ and downwards along an inclined surface, using a free‐flowing bulk material. A relationship was found between the theoretical and effective fill ratio. This relationship shows a certain maximum effective fill ratio and a dependence on the reclaim‐depth. As expected, the effective fill ratio drops quickly when reclaiming upwards, mostly due to flow‐ and throwback: the fill is spilled behind the screw blades and over the axis. Unexpectedly, the effective fill ratio also decreases when reclaiming downwards due to a shift of material towards the non‐reclaiming side where it is left behind forming ridges on the surface. It is expected that all three mechanisms will cause less spill when reclaiming a cohesive material. The experiments provide the desired insight into spill mechanisms during reclaiming. Indeed, the inclined use of the reclaim screw to achieve homogenization is thought feasible when reclaiming downwards.
Characterization of Powder Beds by Thermal Conductivity: Effect of Gas Pressure on the Thermal Resistance of Particle Contact Points
Authors: Shapiro Michael , Dudko Vladislav , Royzen Victor , Krichevets Yuri , Lekhtmakher Samuel , Grozubinsky Victor , Shapira Moshe , Brill Moti
Published: November 2004

The thermal conductivity of ceramic powder packed beds was measured at temperatures below 100 °C for various powder sizes and compositions and under different gas atmospheres. Measurements at low pressures (down to 10 Pa) combined with a theoretical model allowed the elucidation of geometrical and thermal resistance parameters for the contact points between granules. The gap thickness and contact point size were found to be well correlated with the mean particle size. The thermal conductivities of all powders at low pressure were found to differ at most by a factor of two, whereas the solid‐phase conductivities of the powder materials differed by more than one order of magnitude. A theoretical model accounting for the size‐dependence of contact point conductivity is incorporated to rationalize this trend.
Differential alterations in 5α‐reductase type 1 and type 2 levels during development and progression of prostate cancer
Authors: Thomas Lynn N. , Lazier C.B. , Gupta R. , Norman R.W. , Troyer D.A. , O'Brien S.P. , Rittmaster R.S.
Published: November 2004

BACKGROUND

In the prostate, conversion of testosterone to dihydrotestosterone (DHT), by the enzymes 5α‐reductase types 1 and 2 (5αR1, 5αR2) is required for normal growth and probably also for development of prostate cancer (PCa). Finasteride, a 5αR2 inhibitor, was shown to reduce the prevalence of PCa in the Prostate Cancer Prevention Trial. However, inhibition of both 5αR isoenzymes causes a greater decrease in serum DHT. The aim of this study was to assess differential expression of these enzymes at various stages of PCa development.

METHODS

Immunostaining for 5αR1 and 5αR2, using specific, well‐validated antibodies, was evaluated in 26 benign prostatic hyperplasia (BPH) (16 for 5αR2), 53 primary PCa (21 for 5αR2), 18 prostatic intraepithelial neoplasia (PIN), 12 primary PCa treated with neoadjuvant androgen ablation, 15 locally recurrent PCa specimens, and 18 PCa metastases.

RESULTS

The mean area of moderate plus high intensity staining for 5αR1 increased from 4.8 ± 2.8% of total epithelial area in BPH, to 18.9 ± 5.7% in PIN, 17.0 ± 3.2% in primary cancer, 38.0 ± 7.3% in recurrent cancer, and 55.8 ± 8.5% in PCa metastases. The mean staining area for 5αR2 decreased from 58.8 ± 7.2% in BPH, to 21.1 ± 5.5% in PIN and 34.8 ± 6.7% in primary PCa. Staining for 5αR2 was increased in recurrent cancer and PCa metastases compared to primary PCa, at 58.7 ± 5.2% and 69.2 ± 8.7%, respectively.

CONCLUSIONS

5αR1 immunostaining is increased and 5αR2 immunostaining is decreased during development of PCa. In addition, there is increased expression of both 5αR isozymes in recurrent and metastatic cancers, suggesting that both isozymes may be important in the development and progression of PCa. © 2004 Wiley‐Liss, Inc.
Detection and quantification of genotoxicity in wastewater‐treated Tetrahymena thermophila using the comet assay
Authors: Lah B. , Malovrh S. , Narat M. , Cepeljnik T. , Marinsek‐Logar R.
Published: November 2004

In the present study, the comet, or single‐cell, gel electrophoresis assay was adapted for use with the ubiquitous unicellular protozoan Tetrahymena thermophila, and the method was evaluated for its ability to detect DNA damage induced by known genotoxins and wastewater samples. The original comet assay protocol was substantially modified (e.g., lower concentrations of detergents were used in the lysis buffer; electrophoresis time was reduced). Using the modified method, T. thermophila were subjected to short exposures of phenol, hydrogen peroxide, and formaldehyde, leading to concentration‐dependent increases in DNA damage. The genotoxic potential of influent and effluent water samples from a local municipal wastewater treatment plant was evaluated. The results indicated that the influent wastewater was genotoxic and that the genotoxicity in the effluent water was substantially reduced. We assume employing T. thermophila in the use of the comet assay may become a cost‐effective and reliable tool for genotoxicity screening and monitoring of wastewater and similar systems. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 545–553, 2004
Evaluation of the mutagenic potential of urban air pollution in São Paulo, Southeastern Brazil, using the Tradescantia stamen‐hair assay
Authors: Guimarães Eliane T. , Macchione Mariangela , Lobo Débora J. A. , Domingos Marisa , Saldiva Paulo H. N.
Published: November 2004

We used a short‐term bioassay—the Tradescantia stamen‐hair assay (TSH)—to evaluate the toxicity of ambient particles with an aerodynamic diameter less than 10 μm sampled in the metropolitan region of São Paulo, Brazil. Two exposure locations were selected: downtown São Paulo and Caucaia do Alto (mean PM10 levels of 64 and 14 μg/m3, respectively). The experiment was conducted July 11–August 15, 2002, and toxicity was assessed with the Tradescantia stamen‐hair assay (TSH) employing clone KU‐20 of Tradescantia. Four experimental groups were defined: inflorescences collected from plants cultivated in Caucaia, inflorescences collected from plants cultivated in São Paulo (to establish the baseline level of mutations in stamen hairs at both sites), inflorescences collected from plants cultivated in Caucaia and brought to São Paulo and maintained in chambers that received ambient air, and inflorescences collected from plants cultivated in Caucaia and brought to São Paulo and maintained in chambers that received air passed through a particle filter. The frequency of mutations observed in Caucaia was significantly lower than that in the remaining groups. Flower cuttings brought from Caucaia and receiving ambient air of São Paulo showed a rate of mutations similar to that of plants cultivated in São Paulo. Filtering particles from the air reduced the rate of mutation but not sufficiently to reach the level of that in Caucaia. The frequency of mutations observed in São Paulo was significantly associated with PM10 levels on the fifth day before the opening of the flowers (r = 0.47, p = 0.025). Our results indicate that urban particles play a significant role in the development of pollution‐dependent mutations. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 578–584, 2004.
Ultrastructural changes in various organs of the fish Puntius gonionotus fed cadmium‐enriched cyanobacteria
Authors: Rangsayatorn N. , Kruatrachue M. , Pokethitiyook P. , Upatham E. S. , Lanza G. R. , Singhakaew S.
Published: November 2004

The accumulation and toxicity of cadmium in Puntius gonionotus fish that consumed the cyanobacterium Spirulina platensis contaminated with cadmium were studied. Fish were fed cadmium‐contaminated cells for 4 weeks, after which cadmium accumulation in various organs was determined. The highest cadmium content was found in the kidney (56.0 μg Cd/g wet weight). Cadmium was not detected in the gill during the entire 4 weeks of cadmium feeding. Histopathological alteration of cells was observed in the gill, kidney, and liver. The results showed that dietary cadmium caused hypertrophy and edema of gill filaments. Coagulative necrosis and karyolysis of the nucleus were observed in the kidney. Vacuoles and hyaline droplets had accumulated in the epithelial cells of the proximal tubule. In the liver vacuolation of the cytoplasm, infiltration of macrophages, and focal necrosis were found. The ultrastructural changes that occurred in the cells of different organs were similar. These included a proliferation of vacuoles and lysosomes, formation of myelin bodies, degranulation, vesiculation, and dilation of rough endoplasmic reticulum, as well as swelling of mitochondria with loss of cristae. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 585–593, 2004.
Light‐emitting diodes for the illumination of algae in ecotoxicity testing
Authors: Michel Karin , Eisentraeger Adolf
Published: November 2004

Ecotoxic effects of chemicals, preparations, and environmental samples are routinely quantified in standardized algae growth inhibition tests using microalgae like Desmodesmus subspicatus. The intention of this investigation was to prove the suitability of light‐emitting diodes (LEDs) as an alternative to tubular discharge lamps in algae growth inhibition tests. This was approached by demonstrating that growth of algae was similar with both illuminating devices. Growth factors of growth controls were determined using LEDs. Growth curves of different light intensities of LEDs were compared with those of tubular discharge lamps. By testing certain chemicals with both illumination methods comparable results for ErC50 values were obtained. It could be shown that small‐scale construction of incubators using LEDs is possible and could be advantageous, especially for the illumination of algae in 96‐well microplate growth inhibition assays. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 609‐613, 2004.
Regulation of γ‐glutamylcysteine synthetase activity by nerve growth factor
Authors: Pan Zhaohui , Perez‐Polo Regino
Published: November 2004

Nerve growth factor is a neurotrophic factor that regulates neuronal cell development, maintenance, and injury responses in the peripheral and central nervous system. Nerve growth factor reduces injury owing to oxidative stress in rat pheochromocytoma (PC12) cells by increasing intracellular glutathione, in part owing to its stimulation of the activity of γ‐glutamylcysteine synthetase, which is the rate‐limiting enzyme in the synthesis of glutathione. Here we show that nerve growth factor did not increase the activity of γ‐glutamylcysteine synthetase in PC 12 cells at the transcriptional level. Rather, nerve growth factor enhanced the stability of y‐glutamylcysteine synthetase mRNA in PC12 cells. These results suggest that, during oxidative stress, nerve growth factor extended the half‐life of y‐glutamylcysteine synthetase mRNA, thus increasing y‐glutamylcysteine synthetase mRNA levels compared to nerve growth factor‐deprived PC 12 cells.
Field in a complex cylindrical/coaxial cavity subject to time‐harmonic and transient excitation
Authors: Bopp Charles L. , Butler Chalmers M.
Published: November 2004

A coupled integral‐equation method for calculating fields in complex cavities is developed and is applied to cavities comprising multiple cascaded and overlapping coaxial and circular‐cylindrical regions or sections. The field in a section is related to the fields in apertures of planar conducting surfaces, which bound the section. Laboratory cavities are constructed, and their fields are computed from numerical solutions of the integral equations. The results are compared with data obtained through measurements in both the frequency and time domains. The accuracy of the method is also verified by comparison of measured and calculated values of the current and charge on cavity walls. The tools developed are used to investigate the salient features of a sine burst that passes through the complex cavity.
Response of global warming on regional climate change over Korea: An experiment with the MM5 model
Authors: Boo Kyung‐On , Kwon Won‐Tae , Oh Jai‐Ho , Baek Hee‐Jeong
Published: November 2004

This study is to investigate changes in regional surface climate arising from global warming with MM5 downscaling simulation for the period 1971–2100. The main focus is on the drought conditions over Korea. Palmer Drought Severity Index (PDSI) is utilized as a measure of drought severity. The important findings show the increase of surface air temperature by 6°C and precipitation by 25% over Korea at the end of the 21st century. The increasing trend of temperature is associated with an increasing trend of evapotranspiration and precipitation. Climatological precipitation amount appropriate for existing conditions is larger than the precipitation amounts. Hence, it actually produces deficit in precipitation. This exhibits a negative PDSI. As a result droughts are expected to be severe and frequent. Better resolved topography in MM5 induces large changes in local precipitation compared with temperature. Consequently peaks of negative PDSI anomalies appear over southern parts of Korea, where a large reduction in precipitation is noticed in addition to warming.
An ensemble‐type Kalman filter for neutral thermospheric composition during geomagnetic storms
Authors: Codrescu M. V. , Fuller‐Rowell T. J. , Minter C. F.
Published: November 2004

Global circulation models (GCMs) for the thermosphere ionosphere system have been in use for more than 20 years. In the beginning the GCMs were run on supercomputers, were expensive to run, and were used mainly to provide insight into the physics of the region and to interpret measurements. Advances in computer technology have made it possible to run GCMs on desktops and to compare their results with real‐time or near‐real‐time measurements. Today's models are capable of reproducing generic geomagnetic storm effects, but modeling specific storms is still a challenge because accurate descriptions of the energy input during storms are not easy to obtain. One way to compensate for the uncertainty in model inputs for a given period is to assimilate measurements into the model results. In this way, meteorologists have been improving their ability to model tropospheric weather for the last few decades. Data assimilation algorithms have seen an explosive growth in the last few years, and the time has come to apply such techniques to the thermospheric storm effects problem. We present results from an ensemble Kalman filter scheme that determines the best estimate of the global height‐integrated O/N2 ratio by combining GCM results and uncertainties with measurements and their errors. We describe the differences that result from the application of an ensemble Kalman filter to an externally forced system (neutral chemical composition) versus a system dominated by the initial condition and internal dynamics (tropospheric weather and ocean models). The results demonstrate that an ensemble of 10 members is able to characterize the state covariance matrix with sufficient fidelity to enable the Kalman filter to operate in a stable mode. Some information about the external forcing was extracted from the estimate of the state. The general trend of the forcing was followed by the filter, but departures were present over some periods.
Coupling of the human A1 adenosine receptor to different heterotrimeric G proteins: evidence for agonist‐specific G protein activation
Authors: Cordeaux Yolande , IJzerman Adriaan P , Hill Stephen J
Published: November 2004

The present study investigates the effect of varying ligand structure on the ability of agonists to activate guanine nucleotide‐binding proteins of the Gi, Gs and Gq families via the A1 adenosine receptor.

In CHO cells expressing this receptor, inhibition or potentiation of forskolin‐stimulated cAMP accumulation was used as an end point to measure the activation of Gi and, in Pertussis toxin (PTX)‐treated cells, Gs, respectively. Stimulation of inositol phosphate accumulation in PTX‐treated cells was used as an index of Gq activation.

CPA (N6‐cyclopentyladenosine), NECA (5′‐N‐ethyl‐carboxyamidoadenosine) and eight analogues of these ligands presented a range of guanine nucleotide‐binding protein (G‐protein)‐activating profiles. Some ligands could only activate Gi (e.g. 2′deoxyCPA), some primarily Gi and Gs (and only weakly Gq) (e.g. 3′deoxyCPA), highlighting the importance of the ribose hydroxyls in agonist activation of multiple G proteins. CHA (N6‐cyclohexyladenosine) activated Gi, Gs and Gq, but was more efficacious than CPA in activating Gs.

The NECA analogues 5′‐N‐cyclopropyl‐carboxamidoadenosine, 5′‐N‐cyclobutyl‐carboxamidoadenosine and 5′‐N‐cyclopentyl‐carboxamidoadenosine (CPeCA) also activated all three G proteins, although their ability to activate Gs and Gq (relative to CPA) was reduced with increasing substituent size, such that CPeCA produced only a small stimulation (at 100 μM) at Gq, but was a full agonist, relative to CPA, at Gi and Gs.

This study suggests that the A1 adenosine receptor can adopt agonist‐specific conformations, arising from small changes in ligand structure, which lead to the differential activation of Gi, Gs and Gq.

British Journal of Pharmacology (2004) 143, 705–714. doi:10.1038/sj.bjp.0705925
Texts in Context: Afro-Colombian Women's Activism in the Pacific Lowlands of Colombia
Authors: Asher Kiran
Published: November 2004

This paper speaks across the divide between feminist theorists and praxis-oriented gender experts to argue for a more enabling reading of postcolonial feminist critiques of gender and development. Drawing on the activism of Afro-Colombian women in the Pacific Lowlands of Colombia – most especially Matamba y Guasá, a network of black women's organizations from the state of Cauca – it brings attention to the independent ability of women in these locations to reflect and act on their own realities and claims.
Chaotic behavior of a Galerkin model of a two-dimensional flow
Authors: Chen Zhi-Min , Price W. G.
Published: November 2004

Chaotic behavior of a Galerkin model of the Kolmogorov fluid motion equations is demonstrated. The study focuses on the dynamical behavior of limit trajectories branching off secondary periodic solutions. It is shown that four limit trajectories exist and transform simultaneously from periodic solutions to chaotic attractors through a sequence of bifurcations including a periodic-doubling scenario. Some instability regimes display close similarities to those of a discrete dynamical system generated by an interval map.
Conjugate flows for waves with trapped cores
Authors: Lamb Kevin G. , Wilkie Kathleen P.
Published: November 2004

Previous numerical simulations have shown that in a bounded fluid, internal solitary waves with trapped cores become horizontally uniform in their center and have a maximum amplitude that is dependent on the details of the recirculating flow inside the core [K. G. Lamb, “A numerical investigation of solitary internal waves with trapped cores formed via shoaling,” J. Fluid Mech. 451, 109 (2002)]. The flow in the horizontally uniform center of these waves is called a conjugate flow. Here a theoretical model for conjugate flows with a trapped core (also called a vortex core) is presented. The flow in the core is assumed to be steady with constant density. General expressions for arbitrary nonuniform core vorticity are developed which depend on the surface velocity and the mean squared horizontal velocity in the core. Analytic results for cores with constant vorticity are presented for a two-layer fluid with constant density in the lower layer and constant buoyancy frequency in the upper layer. Comparisons of the theory with time-dependent numerical simulations of waves with flat-centered trapped cores in exponential density profiles are made. The theoretical results are shown to accurately predict the amplitude and core thickness of the conjugate flows when the values of the surface velocity and mean squared velocity are taken from the simulations.
A priori and a posteriori tests of inflow conditions for large-eddy simulation
Authors: Keating Anthony , Piomelli Ugo , Balaras Elias , Kaltenbach Hans-Jakob
Published: November 2004

Comparisons of inflow conditions for large-eddy simulations of turbulent, wall-bounded flows are carried out. Consistent with previous investigations, it is found that the spectral content of the inflow velocity is important. Inflow conditions based on random-noise, or small-scale eddies only, dissipate quickly. Temporal and spatial filtering of a time series obtained from a separate calculation indicates that it is important to capture eddies of dimensions equal to or larger than the integral length scale of the flow. Three methods for generating inflow velocity fields are tested in a simulation of spatially developing turbulent channel flow. Synthetic turbulence generation methods that introduce realistic length scales are more suitable than uncorrelated random noise, but still require fairly long development lengths before realistic turbulence is established. A recycling method based on the use of turbulent data obtained from a separate calculation, in different flow conditions, was found to result in more rapid transition. A forcing method that includes a control loop also appears to be effective by generating turbulence with the correct Reynolds stresses and correlations within less than ten channel half heights.
The physics of evaporative instability in bilayer systems: Weak nonlinear theory
Authors: Ozen O. , Narayanan R.
Published: November 2004

A weak nonlinear method of dominant balance is used to describe the fluid dynamics in a bilayer system in the vicinity of phase-change instability. The calculations are performed for a case where gravity and Marangoni effects are ignored. They give us an estimate of the enhancement of heat transfer and, equally importantly, lend credence to physical arguments on the effect of vapor dynamics on the instability.
Confined flow vortex breakdown control using a small rotating disk
Authors: Mununga L. , Hourigan K. , Thompson M. C. , Leweke T.
Published: November 2004

As part of a program to investigate the effectiveness of vortex breakdown in bioreactors for cell and tissue growth, a nonintrusive method of flow control is presented. A small rotating disk flush-mounted opposite to the rotating lid in a confined cylindrical vessel is found to precipitate or delay the onset of vortex breakdown depending on whether it is corotating or counterrotating, respectively. Furthermore, corotation increases the bubble radial and axial dimensions while shifting the bubble in the upstream direction. By contrast, counterrotation tends to reduce the size of the bubble, or completely suppress it, while shifting the bubble in the downstream direction. It has also been shown that corotating swirl addition using the small disk is orders of magnitude more energy efficient in manipulating the vortex breakdown bubble than using end wall rotation.
Highly efficient gaseous sample loading technique for diamond anvil cells
Authors: Zhao Jiyong , Shen Guoyin , Sturhahn Wolfgang , Alp E. Ercan
Published: November 2004

A clean and highly efficient technique has been developed to load diamond anvil cells (DACs) using a small amount of gaseous samples. The loading process consists of two steps. First, gas is condensed on a designated cold surface in a pre-evacuated system; second, the solidified sample is loaded into a DAC at liquid-nitrogen temperature. A hundred milliliters of gas at ambient condition is typically required to produce a solidified sample. The use of solid sample material for DAC loading is beneficial to a clean loading process. We demonstrated this technique by loading isotopically enriched (99.925%-83Kr) krypton into a DAC. 200 ml of this rare and expensive gas were solidified with 99.6% efficiency and almost completely recovered.
A low-power timing discriminator for space instrumentation
Authors: Devoto P. , Médale J.-L. , Aoustin C. , Sauvaud J.-A.
Published: November 2004

A front-end electronics for three-dimensional time-of-flight space plasma analyzers has been developed. These mass spectrometers, allowing the determination of the distribution functions of the main ion species, are based on the selection of the ion energy per charge and arrival direction using an electrostatic analyzer, and on the determination of their velocity from the time separating a start and a stop pulse. The start pulse is provided by the collection on a microchannel plate (MCP) of secondary electrons emitted when each ion crosses a thin carbon foil. The stop pulse is provided by the ion hitting a second MCP. The aim of the electronics presented in this article is to process the signals provided by MCPs to generate logic pulses, allowing the measurement of precise time differences. The design consists of an amplifier and a timing discriminator which performs a timing compensation to eliminate the time walk. A first version of the circuit has been developed and achieves a time walk of ∼400 ps for an input amplitude dynamic range of 25 dB. The total power dissipation per channel is ∼14 mW at an event rate of 100 KHz and ∼19 mW at a rate of 1 MHz. The influence of the temperature on the circuit behavior has been investigated. The performances of the circuit in a complete detector were also evaluated. This circuit is designed to be used in various designs for future missions.
Analysis of heat flow in layered structures for time-domain thermoreflectance
Authors: Cahill David G.
Published: November 2004

The iterative algorithm of Feldman for heat flow in layered structures is solved in cylindrical coordinates for surface heating and temperature measurement by Gaussian-shaped laser beams. This solution for the frequency-domain temperature response is then used to model the lock-in amplifier signals acquired in time-domain thermoreflectance measurements of thermal properties.
Heat power source controller circuit
Authors: Madrid F. , Jordà X. , Vellvehi M. , Perpiñà X. , Godignon P.
Published: November 2004

Experimental works on thermal management of electronic systems, such as thermal resistance or thermal conductivity measurement, often require a controlled heat power source. This article proposes a circuit based on an integral automatic controller that sets a heat power dissipation level of a power metal-oxide-semiconductor field effect transistor used as a heating device. It can operate in dc mode, setting a steady power generation, and in pulsed mode, controlling a transient power wave form. The controller operation principle is established together with all details for its implementation and use.