bluuebunny/crossref_metadata_2025 huggingface dataset:
Multifunctional covalent and ionic coupling agents of maleic anhydride modified polyethylene
Authors: Colbeaux Aimeline , Fenouillot Françoise , David Laurent , Gerard Jean‐François , Taha Mohamed , Wautier Henri
Published: May 2007

Amine and alcohol functional dendritic polymers were used as covalent coupling agents for maleic anhydride grafted polyethylene and their efficiency compared with metallic salt and zinc acetate, acting as an ionic coupling agent. The crosslinking reactions in the molten state were carried out at 150°C in an internal mixer and the resulting modified polyethylenes were characterized by dynamic mechanical analysis and Small angle X‐ray Scattering. These agents led to efficient coupling and crosslinking. The covalent coupling reactions were conducted in a heterogeneous multiphase system: The kinetics of crosslinking depends on the nature of the coupling agent: at 150°C, the reactions were completed within 5 min. with the amine hyperbranched polymer and 20 min. with the alcohol functionalized dendritic polymer. The zinc acetate forms ionic interactions with the grafted polyethylene in less than 1 min. Ionic interactions are thermo mechanically reversible; they correspond to electronic density fluctuations evidenced by SAXS. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Swelling and dye sorption studies of AAm/SA hydrogels crosslinked by glutaraldehyde and divinylbenzene
Authors: Üzüm Ömer Barış , Kundakci Semiha , Durukan H. Berna , Karadağ Erdener
Published: May 2007

Highly swollen acrylamide (AAm)/sodium acrylate (SA) hydrogels were prepared by free radical solution polymerization in aqueous solution of AAm with SA as comonomer and two multifunctional crosslinkers such as glutaraldehyde (GL) and divinylbenzene (DVB). Water absorption and percentage swelling were determined gravimetrically. The influence of SA content in hydrogels was examined. Percentage swelling ratio of AAm/SA hydrogels was increased up to 2946–12,533%, while AAm hydrogels swelled up to 1326–1618%. The values of equilibrium water content of the hydrogels are between 0.9297–0.9921. Diffusion behavior was investigated. Water diffusion into hydrogels was found to be non‐Fickian in character. Adsorption properties of AAm/SA hydrogels in aqueous thionin solution have been investigated. Finally, the amount of sorbed thionin per gram of dry hydrogel (qe) was calculated to be 4.81 × 10−6−11.69 × 10−6 mol thionin per gram for hydrogels. Removal efficiency (RE%) of the AAm/SA hydrogels was changed range 37.03–68.82%. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007
Wissenschaftsstädte – Zur Bedeutung des Topos der ‘kreativen Stadt’ für die Wissensproduktion
Authors: Heßler Martina
Published: May 2007

Science Cities: What the Concept of the Creative City Means for Knowledge Production. – The article aims to show that the relationship of science and the city has changed since the 1970s in the context of the knowledgeable society. While cities have principally been regarded as the typical space of science, of new ideas and innovation for centuries, since the 1960s and 1970s universities, research institutes as well as industrial research institutes have relocated to the periphery of cities. There, however, these sites of knowledge have been organized in an ‘urban mode’. That means that the concept of the city as a place of science and innovation has determined the architectural, spatial, and social organization of these sites on the periphery of cities. Certain features of the city have been copied, such as social infrastructures, places of communication, restaurants, cafes etc., while others have been left out – housing, cinema, theatre etc. An ‘urban mode of knowledge production’ in the sense of a very stylized model of the city has become a tool to enhance the production of scientific and technological knowledge. – The article exemplifies this by focusing on a case study, namely of the so‐called ‘Science City’ of the Siemens Company in Munich‐Neuperlach.
Acute hydrodynamic forces and apoptosis: A complex question
Authors: Mollet Mike , Godoy‐Silva Ruben , Berdugo Claudia , Chalmers Jeffrey J
Published: May 2007

A second generation flow contraction device was developed and modeled which allows cells to be subjected to well‐defined hydrodynamic forces. Studies were conducted with this system on wild‐type Chinese Hamster Ovary cells (CHO‐K1) and a strain of CHO cells which expresses the human Bcl‐2▵ gene (CHO‐bcl‐2). In this study, the following questions were asked: (1) Does an acute hydrodynamic force induce apoptosis in wild‐type CHO and CHO‐bcl‐2 cells? (2) Does the type of culture media make a difference with respect to the induction of apoptosis or necrosis? and (3) Does culture history affect induction of apoptosis or necrosis? The results obtained with this new flow contraction device and corresponding computer simulations are consistent with previously published studies with respect to the level of energy dissipation rate (EDR) required to create significant cell lysis. Second, while detectable relative to the control in the T‐flask experiments, only a small fraction of the cells become apoptotic when exposed to a sub‐lysis level of EDR (<108 W · m−3). Third, cells cultured in suspension with serum free media do not exhibit any higher or lower sensitivity (with respect to apoptosis) to various levels of EDR when compared to control cultures grown in T‐flask and serum containing media; on the other hand, necrosis is significantly increased in experiments performed on suspended cells without serum. Fourth, the addition of the Bcl‐2 gene product might slightly reduce the occurrence of apoptosis in T‐flask culture; however, the baseline response is so low that the difference is insignificant. Biotechnol. Bioeng. 2007; 98: 772–788. © 2007 Wiley Periodicals, Inc.
New method to determine the mass transfer resistance of sterile closures for shaken bioreactors
Authors: Anderlei Tibor , Mrotzek Christian , Bartsch Stefan , Amoabediny Ghassem , Peter Cyril P. , Büchs Jochen
Published: May 2007

In this paper a novel and easily applied method to measure the mass transfer resistance of the sterile closures (e.g. cotton plug) of shaken bioreactors is introduced. This method requires no investment in special equipment (e.g. an oxygen sensor) and can be performed with the materials usually available in typical laboratories. The method is based on the model of Henzler et al. (1986), which mechanistically describes mass transfer through the sterile closure of a shaken bioreactor based on diffusion coupled with Stefan convection. The concentration dependency of the multi‐component diffusion coefficients is taken into account. The water loss from two equivalent shaken bioreactors equipped with sterile closures during several days of shaking is measured. One flask contains distilled water, the other a saturated salt solution. From the water evaporation rate in each of the two flasks, the new model presented calculates the relative humidity in the environment, the average diffusion coefficient of oxygen in the sterile closure ($D_{{\rm O}_2 }$), and the diffusion coefficient of carbon dioxide ($D_{{\rm CO}_2 }$). The diffusion coefficient of carbon dioxide ($D_{{\rm CO}_2 }$) only depends on the density and material properties of the sterile closure and not on the gas concentrations and is, therefore, an ideal parameter for the characterization of the mass transfer resistance. This new method is validated experimentally by comparing the diffusion coefficient of oxygen ($D_{{\rm O}_2 }$) to a measurement by the classic dynamic method; and by comparing the calculated relative humidity in the environment to a humidity sensor measurement. Biotechnol. Bioeng. 2007;98: 999–1007. © 2007 Wiley Periodicals, Inc.
A Concerted Approach for the Determination of Molecular Conformation in Ordered and Disordered Materials
Authors: Sehnert Jan , Senker Jürgen
Published: May 2007

We present the successful application of a concerted approach for the investigation of the local environment in ordered and disordered phases in the solid state. In this approach we combined isotope labeling with computational methods and different solid‐state NMR techniques. We chose triphenylphosphite (TPP) as an interesting example of our investigations because TPP exhibits two crystalline modifications and two different amorphous phases one of which is highly correlated. In particular we analyzed the conformational distribution in three of these phases. A sample of triply labeled 1‐[13C]TPP was prepared and 1D MAS as well as wide‐line 13C NMR spectra were measured. Furthermore we acquired 2D 13C wide‐line exchange spectra and used this method to derive highly detailed information about the phenyl orientation in the investigated TPP phases. For linkage with a structure model a DFT analysis of the TPP molecule and its immediate environment was carried out. The ab initio calculations of the 13C chemical shift tensor in three‐ and six‐spin systems served as a base for the calculation of 1D and 2D spectra. By comparing these simulations to the experiment an explicit picture of all phases could be drawn on a molecular level. Our results therefore reveal the high potential of the presented approach for detailed studies of the mesoscopic environment even in the challenging case of amorphous materials.
The First Direct Enzymatic Hydrolysis of Alicyclic β‐Amino Esters: A Route to Enantiopure cis and trans β‐Amino Acids
Authors: Forró Enikõ , Fülöp Ferenc
Published: May 2007

The first direct enzymatic method is reported for the synthesis of cis and trans β‐amino acid enantiomers through the lipase‐catalyzed enantioselective hydrolysis of alicyclic β‐amino esters in organic media. High enantioselectivities (E usually >100) were observed when the Candida antarctica lipase B catalyzed reactions were performed with H2O (0.5 equivalents) in iPr2O at 65 °C. The resolved products, obtained in good yields (≥42 %), could be easily separated.
Formation Process and Thermodynamic Poperties of Calcite
Authors: Nan Zhao‐Dong , Shi Zuo‐Yi , Qin Mei , Hou Wan‐Guo , Tan Zhi‐Cheng
Published: May 2007

The fast mixing of aqueous solutions of calcium chloride and sodium carbonate resulted in crystalline forms of vaterite and calcite under vigorous stirring. Then, the vaterite was transformed to pure calcite within about 180 min. The crystalline forms all grew with experimental time increase. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT‐IR), and X‐ray diffraction spectroscopy (XRD) techniques were employed to characterize the as‐prepared samples. The heat capacity of the stable as‐synthesized calcite was determined by means of an adiabatic calorimeter from 80 to 390 K. The thermodynamic functions of the calcite were derived based on the relationships among the thermodynamic functions and the function of the measured heat capacity with respect to temperature.
A Novel Synthesis of Alkaline Earth Silicate Phosphor Sr3MgSi2O8:Eu2+,Dy3+
Authors: Pan Wen , Ning Gui‐Ling , Wang Jing‐Hui , Lin Yuan
Published: May 2007

A novel method for synthesizing long afterglow silicate phosphor Sr3MgSi2O8:Eu2+,Dy3+using TEOS and inorganic powders as reactants was reported. Acetic acid as a catalyzer controlled the hydrolysis of TEOS by adjusting pH value of the system. The morphologies of precursor were characterized by transmission electron microscope (TEM). The structure and optical properties of the phosphor powders were systematically investigated by means of X‐ray diffraction and spectrofluorometry. TEM images have reflected the core‐shell structure and quasi‐spherical morphology of the precursor particles. It was found that the single‐phase Sr3MgSi2O8 crystalline structures were obtained at 1050 and 1250 °C for the samples prepared with the nano‐coating method and the solid state reaction, respectively. The emission intensities of the phosphors prepared by the present method were higher than those by the conventional process. Also, the afterglow characteristic was better than that prepared by solid‐state reaction in the comparable condition.
Spectral Studies on the Interaction between Mercuric Ion and ApoCopC
Authors: Zheng Xiao‐Yan , Pang Er‐Guo , Li Hui‐Qing , Zhao Ya‐Qin , Yang Bin‐Sheng
Published: May 2007

The interaction between mercuric ion and apoCopC in the absence or presence of cupric ion was investigated through difference UV spectra in Hepes buffer (10 mmol·L−1) at pH 7.4. The results suggest that mercuric ion can bind to C‐ and N‐terminal binding sites of apoCopC, and the conditional binding constants were calculated to bekN=(6.79±1.12)×106 mol−1·L and kC=(3.06±0.05)×105 mol−1·L. Using urea as a chemical agent, the conformational stabilities of apoCopC and Hg2+N‐CopC‐Hg2+C were monitored by fluorescence spectrum in Hepes buffer (50 mmol·L−1) at pH 7.4. The free energy of stabilization is (14.69±0.85) and (16.66±0.55) kJ·mol−1, respectively. Hg2+N‐CopC‐Hg2+C is more stable than apoCopC.
Synthesis and Characterization of Ordered Mesoporous Aluminosilicate Molecular Sieves with High Stability in High‐Temperature Steam
Authors: Luo Yong‐Ming , Hou Zhao‐Yin , Jin Ding‐Feng , Zheng Xiao‐Ming
Published: May 2007

The ordered mesoporous aluminosilicate molecular sieve (MASMS‐1) stable in the high‐temperature steam has been successfully synthesized from the assembly of diluted ZSM‐5‐type precursor with mesoporous MCM‐41. The material was characterized by XRD, N2 adsorption‐desorption, FE‐SEM, TEM, FT‐IR spectroscopy and 27Al MAS NMR techniques. This mesoporous material shows high stability in the high‐temperature steam [H2O (ψ=20%) in N2 at 800 °C for 4 h], which might be ascribed to the synergistic effect of both thick walls containing zeolite‐like five‐membered ring subunits and highly condensed surface silanol groups.
Fatty Acid Composition of Tobacco Seed Oil and Synthesis of Alkyd Resin
Authors: Mukhtar Azam , Ullah Habib , Mukhtar Hamid
Published: May 2007

The fatty acid composition of tobacco seed oil revealed that the oil is rich in unsaturated fatty acids, having linoleic acid (71.63%), oleic acid (13.46%) and palmitic acid (8.72%) as the most abundant unsaturated and saturated fatty acids respectively. So the tobacco oil was characterized as semi‐drying type on the basis of fatty acid composition. The synthesis of alkyd resin was carried out by alcoholysis or monoglyceride process using an alkali refined tobacco seed oil, pentaerythritol, cis‐1,2,3,6‐tetrahydrophthalic anhydride along with lithium hydroxide as catalyst. The alkyd resin so prepared was found to be bright and of low color with high gloss. The drying and hardness properties and adhesion of the tobacco seed oil derived alkyd resin were also found a bit superior to those of other alkyd resins of the same oil length. In addition, the water and acid resistance of the said alkyd was also found comparable to the other alkyds.
Pretransplant positive positron emission tomography/gallium scans predict poor outcome in patients with recurrent/refractory Hodgkin lymphoma
Authors: Jabbour Elias , Hosing Chitra , Ayers Gregory , Nunez Rodolfo , Anderlini Paolo , Pro Barbara , Khouri Issa , Younes Anas , Hagemeister Fredrick , Kwak Larry , Fayad Luis
Published: May 2007

BACKGROUND

The objective was to determine the prognostic value of functional imaging (FI) in predicting outcome of patients with recurrent/refractory Hodgkin lymphoma (HL) before undergoing high‐dose chemotherapy with autologous stem cell transplantation (ASCT).

METHODS

Clinical and imaging data were retrospectively reviewed in 211 consecutive patients treated with ASCT from February 1993 to May 2004. The FI results were correlated with progression‐free survival (PFS) and overall survival (OS) using Kaplan‐Meier survival analysis.

RESULTS

Responses were assessed by conventional criteria and evaluated by positron emission tomography (PET) (n = 68) and gallium scans (n = 144) before ASCT. A complete response (CR) or unconfirmed CR (CRu) was seen in 51% of patients, a partial response (PR) in 41% of patients, and stable or progressive disease in 7% of patients. FI was positive in only 6 of 110 (5%) of CR/CRu patients, in 48 of 86 (56%) of PR patients, and in all 3 patients with progressive disease. The 3‐year PFS was 69% for patients with negative FI versus 23% for patients with positive FI (P < .0001). The 3‐year OS rates were 87% and 58%, respectively (P < .0001). The 3‐year PFS for patients in PR with negative FI was 51% comparable to patients in CR (76%) versus 27% for patients in PR with positive FI (P < .0001). In a multivariate model, positive FI was found to be independently prognostic of PFS.

CONCLUSIONS

Pretransplant FI status predicts outcome in patients with recurrent/refractory HL. Positive FI confers a poor prognosis, independent of other traditional presalvage prognostic factors. Cancer 2007. © 2007 American Cancer Society.
1,4‐Dimethylenespiropentane: A Unique Model System for Studying Fermi Resonance in Raman Optical Activity
Authors: Hug Werner , Haesler Jacques , Kozhushkov Sergei I. , de Meijere Armin
Published: May 2007

The C2‐symmetric title compound, a small, rigid hydrocarbon molecule with two distinct, strongly interacting vibrational chromophores, represents a unique model system for testing computational approaches to Raman optical activity (ROA) beyond the isolated molecule and the harmonic approximation. We show that the experimental Raman and ROA spectra are marked by the presence of strong Fermi resonances, and that the shape and relative size of the bands which we attribute to such resonances strongly depend on the solvent environment of the molecule. On the other hand, the dominant computed ROA couplet, arising from the CC stretching vibrations, is absent in the spectra measured in the condensed phase. The strong dependence of the computed size of the couplet on the description of the diffuse part of the electron distribution suggests that this absence is due to nonspecific interactions in the condensed phase.
Rapid Intersystem Crossing in Closely‐Spaced but Orthogonal Molecular Dyads
Authors: Harriman Anthony , Mallon Laura J. , Ulrich Gilles , Ziessel Raymond
Published: May 2007

A borondipyrromethene (bodipy) dye is equipped with a 4‐pyridine residue attached via the meso position. The strong fluorescence inherent to this class of dye is extinguished on protonation of the pyridine N atom. For the corresponding N‐methylpyridinium derivative, fluorescence from the dye fragment is also extensively quenched due to the onset of a light‐induced charge‐shift reaction. The resultant charge‐transfer state (CTS) is weakly fluorescent and decays primarily by way of population of the triplet excited state localized on the bodipy dye. Time‐resolved spectral studies provide rate constants for all the steps involved in the forward and reverse charge‐shift reactions. An interesting feature is that the lifetime of the CTS, around 1 ns, correlates with the viscosity of the solvent as might be expected if the rate‐limiting step involves a substantial change in geometry. There is an unexpectedly small activation energy for the reverse charge‐shift reaction, even allowing for the fact that this involves triplet formation. Local fluorescence is restored on cooling to 77 K.
Thermal and Mechanical Properties of Silicon Tetrachloride (SiCl4) and Germanium Tetrachloride (GeCl4) in Their Vapor and Liquid Phases
Authors: Prat O. P. , Cloitre T. , Aulombard R.‐L.
Published: May 2007

The most‐common physical properties of the precursor species SiCl4 and GeCl4 in their vapor and liquid phases are compiled from several sources in the literature. General expressions over a large range of temperature are proposed either by the use of referenced expressions or by the use of suitable empirical models.
MOCVD of BiFeO3 Thin Films on SrTiO3
Authors: Thery J. , Dubourdieu C. , Baron T. , Ternon C. , Roussel H. , Pierre F.
Published: May 2007

Bi‐Fe‐O thin films are grown by liquid‐injection metal‐organic (MO)CVD on (001) SrTiO3 substrates using two different bismuth precursors, Bi(tmhd)3 and Bi(mmp)3. The precursor Bi(mmp)3 is found to be more effective for Bi incorporation in the films. Epitaxial BiFeO3 films are obtained and no evidence for secondary phases such as Fe2O3 or Bi2O3 is found by X‐ray diffraction (XRD) or transmission electron microscopy (TEM) studies. However, the presence of a multiple binding environment for Fe3+ is shown from the X‐ray photoelectron spectroscopy (XPS) analyses. Moreover, XPS shows evidence of a Fe2+/Fe3+ valence mixed state. A saturation magnetization of 70 emu cm–3 is measured. This value is much higher than that reported for the bulk BiFeO3 material. Both the double valence for Fe ions and the enhanced magnetization may originate in the presence of non‐fully‐oxidized γ‐Fe2O3.
CVD of Metals Using Alcohols and Metal Acetylacetonates, Part I: Optimization of Process Parameters and Electrical Characterization of Synthesized Films
Authors: Premkumar P.A. , Bahlawane N. , Kohse‐Höinghaus K.
Published: May 2007

A new successful strategy is developed for the production of Ni, Cu, and Co films using commercially available metal acetylacetonates as precursors. Pulsed spray evaporation (PSE) CVD is applied utilizing only alcohols as solvents and reducing agents. The efficiency of the process, with respect to controlling parameters such as pulse width, pulsing frequency, carrier gas flow rate, and concentration of the precursors in the feedstock, is optimized. The growth of metal films as a function of substrate temperature, deposition pressure, and duration of deposition, is examined. Results demonstrate that the metal films grow on various substrates, including glass and SiC, without any incubation time and do not need a seed layer. Resulting resistivities are close to those of the bulk materials for Ni and Cu films, while a value of 150 μΩ cm, which improves upon annealing, is measured for Co films.
Automated screening versus manual screening: A comparison of the ThinPrep® imaging system and manual screening in a time study
Authors: Schledermann Doris , Hyldebrandt Tina , Ejersbo Dorthe , Hoelund Berit
Published: May 2007

The ThinPrep Imaging System (TIS) is an automated system that assists cytotechnologists in the primary screening of ThinPrep liquid based cervical samples. Between June 1, 2004, and April 1, 2005, four experienced cytotechnologists participated in the study in which the duration of the screening procedure was timed for each of the 11,354 slides included. In every slide 22 fields of view were reviewed, and the samples that contained potentially abnormal cells were fully screened. The screening time was reduced by 42% (mean) (p < 0.001). By manual rescreening of the negative TIS samples, abnormal cells were found in 10 samples (false negative rate 0.14%). In every case the abnormal cells had been identified by the scanner, but misinterpreted by the cytotechnologist. These findings stressed the importance of carefulness in the interpretation of the marked fields and beyond that helped the cytotechnologists and pathologists to have more confidence in the automated system. Diagn. Cytopathol. 2007;35:348–352. © 2007 Wiley‐Liss, Inc.
Primary Ewing sarcoma/PNET of the kidney: Fine‐needle aspiration, histology, and dual color break apart FISH Assay
Authors: Kang Steven H. , Perle Mary Ann , Nonaka Daisuke , Zhu Hongfa , Chan Wai , Yang Grace C. H.
Published: May 2007

A 34‐year‐old previously healthy Hispanic man presented with lower back pain. CT scan revealed an 8‐cm space‐occupying lesion in the superior pole of the left kidney with numerous small lytic lesions in the skull, vertebrae, ribs, and pelvic bones. CT‐guided fine‐needle aspiration biopsy revealed a high‐grade primitive small round cell tumor with the tumor cells being strongly positive for CD99 and vimentin. The patient subsequently underwent a left nephrectomy. Fluorescence in situ hybridization analysis using a DNA probe for the Ewing Sarcoma breakpoint region 1 (EWSR1) on chromosome 22g12 revealed a rearrangement of the EWSR1 locus. The diagnosis of primary Ewing sarcoma/primitive neuroectodermal tumor of the kidney was established. Diagn. Cytopathol. 2007;35:353–357. © 2007 Wiley‐Liss, Inc.
Weight overestimation as an indicator of disordered eating behaviors among young women in the United States
Authors: Conley Amanda , Boardman Jason D.
Published: May 2007

Objective:

This paper examines the association between weight overestimation and symptoms of disordered eating behaviors using a nationally representative sample of young women.

Method:

We use data from Wave III of the National Longitudinal Study of Adolescent Health to compare self‐reported weight (in pounds) to measure weight obtained by interviewers using a scale. Focusing on normal weight women between the ages of 18 and 24 (n = 2,805) we compare the discrepancy in self‐reported and measured weight among women with and without any disordered eating behaviors.

Results:

Women who over report their weight by at least five percent are significantly more likely than those who either under report or accurately report their weights to exhibit disordered eating behaviors. These results persist despite controlling for distorted body image.

Conclusion:

Our findings support both motivational and perceptual bias explanations for overestimating weight among those who exhibit disordered eating behaviors. We argue that weight over‐estimation, together with other important information regarding women's nutrition, exercise, mental health, and health‐related behaviors, should be treated as a potential indicator for the diagnosis of an eating disorder among young normal weight women. © 2007 by Wiley Periodicals, Inc. Int J Eat Disord 2007
B‐1a cells are imprinted by the microenvironment in spleen and peritoneum
Authors: Stoermann Britta , Kretschmer Karsten , Düber Sandra , Weiss Siegfried
Published: May 2007

B‐1a cells are found mainly in the peritoneal cavity of mice but are also present in the spleen. Gene expression profiling defined many genes differentially expressed in B‐1a cells from these two sites. To see whether this gene expression pattern was imprinted by the particular microenvironment, peritoneal or spleen cells from recombinant L2 mice mainly consisting of B‐1a cells were adoptively transferred into Rag1–/– mice. Re‐isolated peritoneal and splenic B‐1a cells were analyzed for expression of three indicator genes – vcam‐1, adamdec1 and spi‐c. The expression of these genes was up‐regulated in splenic and down‐regulated in peritoneal cells. This particular pattern was observed for peritoneal or splenic donor cells transferred either intraperitoneally or intravenously. Similar results were obtained when levels of surface IgM or frequencies of Mac‐1+ B‐1 cells were compared after transfer. This suggests that the environment induces the particular genetic program of B‐1a cells and argues against an independent ontogeny.
High‐Yield Synthesis of a New Layered High‐Nuclearity Carbonyl Osmium‐Rhodium Cluster Complex – Synthesis, Structural Characterization, and Electrochemistry of [PPN][Os9Rh3(μ‐CO)2(CO)26]
Authors: Po‐Kwan Lau Jasmine , Gu Yan‐Juan , Wong Wing‐Tak
Published: May 2007

A direct and high‐yield synthetic route for a novel dodecanuclear osmium‐rhodium mixed‐metal cluster is presented. The redox properties of the cluster were examined, and it was found that the anion behaves as an “electron reservoir”. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Identification of novel alternatively spliced BRCA1‐associated RING domain (BARD1) messenger RNAs in human peripheral blood lymphocytes and in sporadic breast cancer tissues
Authors: Lombardi Grazia , Falaschi Elisabetta , Cristofano Claudio Di , Naccarato Antonio Giuseppe , Sensi Elisa , Aretini Paolo , Roncella Manuela , Bevilacqua Generoso , Caligo Maria Adelaide
Published: May 2007

BARD1 (BRCA1‐associated RING domain) is the dominant binding partner of BRCA1 in vivo. The BARD1 gene has been reported to be mutated in a subset of breast and ovarian cancer patients and BARD1 germ‐line mutations have been identified in breast cancer patients negative for BRCA1 or BRCA2 gene alterations. In the present study, we show by RT‐PCR and direct sequencing analysis the occurrence of seven novel and one previously identified BARD1 splicing variants in human lymphocytes and breast cancers. Two of the eight variants (BARD1δ and BARD1 ΔRIN) preserve a correct open reading frame and could encode BARD1 internally deleted proteins, while the remaining six variants display premature stop codons. Characterization of the relative expression of BARD1 FL, BARD1δ, and BARD1 ΔRIN using quantitative PCR analysis indicated that the mean expression levels of BARD1 FL, BARD1δ, and BARD1 ΔRIN were significantly higher in tumors than in morphologically normal tissues and lymphocytes. However, we were unable to identify either qualitatively or quantitatively tumor‐specific expression patterns of the identified BARD1 splicing variants. © 2007 Wiley‐Liss, Inc.
Levels of error processing in Huntington's disease: A combined study using event‐related potentials and voxel‐based morphometry
Authors: Beste Christian , Saft Carsten , Konrad Carsten , Andrich Jürgen , Habbel Anne , Schepers Inga , Jansen Andreas , Pfleiderer Bettina , Falkenstein Michael
Published: May 2007

Huntington's Disease (HD) is a neurogenetic disorder accompanied by an atrophy of the striatum and hence of the dopaminergic (DA) system. Neural processes subserving error processing presumably depend on the DA system. We assessed error processing in manifest HD and in presymptomatic HD‐gene‐mutation‐carriers (pHD) with event‐related potentials reflecting error processing (the error negativity or error‐related negativity and the error positivity derived from a flanker‐task. We found a reduction of the Ne in the case of HD compared to pHD reflecting dopamine system pathology. Despite the Ne being reduced in HD, behavioral adaptation was possible. In addition, the error‐rates did not differ between the groups. Optimized voxel‐based morphometry revealed that grey matter volume in the medial frontal gyrus is correlated with the Ne amplitude in symptomatic patients. In addition, the effect of a Ne‐reduction was related to the grey matter underneath the medial frontal gyrus, which is in line with two theories of the Ne. In contrast, the Pe did not differ between the groups, suggesting that the Pe is decoupled from the DA system. Interestingly we found a reduction of a late slow negativity on correct responses, which possibly reflects decreased preparatory processes in HD compared to pHD as induced by the DA alterations in HD. In conclusion a deterioration in error processing in HD compared to pHD is mainly reflected by the Ne. The deterioration might rely on two factors: a neurofunctional and a neuroanatomical. Hum Brain Mapp 2008. © 2007 Wiley‐Liss, Inc.
Variability of the paracingulate sulcus and morphometry of the medial frontal cortex: Associations with cortical thickness, surface area, volume, and sulcal depth
Authors: Fornito Alex , Wood Stephen J. , Whittle Sarah , Fuller Jack , Adamson Chris , Saling Michael M. , Velakoulis Dennis , Pantelis Christos , Yücel Murat
Published: May 2007

The structural and functional consequences of interindividual variations in cortical morphology are poorly understood. In this study, we examined the relationship between one well‐characterized variation of the medial frontal lobes, variability of the paracingulate sulcus (PCS), and grey matter volume, cortical thickness, surface area, and sulcal depth of the adjacent anterior cingulate cortex (ACC) and paracingulate cortex (PaC). Seventy‐seven healthy individuals were assigned to one of four groups depending on PCS incidence in both hemispheres: left‐present, right‐absent; left‐absent, right‐present; both absent; or both present. Comparing these groups on each measure yielded four primary findings: (1) The presence of a PCS was associated with increased PaC and decreased ACC grey matter volume in the hemisphere in which it was apparent, with an almost identical pattern being observed for surface area; (2) there was a more complex relationship between PCS variability and regional thickness, such that a PCS in the left hemisphere was associated with increased left PaC and right ACC thickness, with no comparable effects being observed for the presence of a right PCS; (3) the depths of all major left hemisphere sulci in the region were strongly positively correlated, whereas no such associations were apparent in the right hemisphere; and (4) a leftward asymmetry in PaC thickness was specifically associated with better performance on a test of spatial working memory ability. These results provide evidence for a complex interhemispheric relationship between sulcal variability and cortical morphometry, and indicate that such relationships may be important for understanding individual differences in cognitive abilities. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Cross‐cultural music phrase processing: An fMRI study
Authors: Nan Yun , Knösche Thomas R. , Zysset Stefan , Friederici Angela D.
Published: May 2007

The current study used functional magnetic resonance imaging (fMRI) to investigate the neural basis of musical phrase boundary processing during the perception of music from native and non‐native cultures. German musicians performed a cultural categorization task while listening to phrased Western (native) and Chinese (non‐native) musical excerpts as well as modified versions of these, where the impression of phrasing has been reduced by removing the phrase boundary marking pause (henceforth called “unphrased”). Bilateral planum temporale was found to be associated with an increased difficulty of identifying phrase boundaries in unphrased Western melodies. A network involving frontal and parietal regions showed increased activation for the phrased condition with the orbital part of left inferior frontal gyrus presumably reflecting working memory aspects of the temporal integration between phrases, and the middle frontal gyrus and intraparietal sulcus probably reflecting attention processes. Areas more active in the culturally familiar, native (Western) condition included, in addition to the left planum temporale and right ventro‐medial prefrontal cortex, mainly the bilateral motor regions. These latter results are interpreted in light of sensorimotor integration. Regions with increased signal for the unfamiliar, non‐native music style (Chinese) included a right lateralized network of angular gyrus and the middle frontal gyrus, possibly reflecting higher demands on attention systems, and the right posterior insula suggesting higher loads on basic auditory processing. Hum Brain Mapp, 2008. © 2007 Wiley‐Liss, Inc.
Teaching and hospital production: The use of regression estimates
Authors: Lehner Laura A. , Burgess James F.
Published: May 2007

Medicare's Prospective Payment System pays U.S. teaching hospitals for the indirect costs of medical education based on a regression coefficient in a cost function. In regression studies using health care data, it is common for explanatory variables to be measured imperfectly, yet the potential for measurement error is often ignored. In this paper, U.S. Department of Veterans Affairs data is used to examine issues of health care production estimation and the use of regression estimates like the teaching adjustment factor. The findings show that measurement error and persistent multicollinearity confound attempts to have a large degree of confidence in the precise magnitude of parameter estimates.
Health care reform : Motivation for discrimination?
Authors: Navin John C. , Pettit Mary Anne
Published: May 2007

One of the major issues in the health care reform debate is the requirement that employers pay a portion of their employees' health insurance premiums. This paper examines the method for calculating the employer share of the health care premiums, as specified in the President's health care reform proposal. The calculation of the firm's cost of providing employee health care benefits is a function of marital status as well as the incidence of two‐income earner households. This paper demonstrates that this method provides for lower than average premiums for married employees with no dependents in communities in which there is at least one married couple where both individuals participate in the labor market. This raises the non‐wage labor costs of employing single individuals relative to individuals which are identical in every respect except their marital status. This paper explores the economic implications for hiring, as well as profits, for firms located in a perfectly‐competitive industry. The results of the theoretical model presented here are clear. Under this proposed version of health care reform, ceteris paribus, firms have a clear preference for two‐earner households. This paper also demonstrates that the incentive to discriminate is related to the size of the firm and to the size of the average wage of full‐time employees for firms which employ fewer than fifty individuals. While this paper examines the specifics of President Clinton's original proposal, the conclusions reached here would apply to any form of employer‐mandated coverage in which the premiums are a function of family status and the incidence of two‐earner households.
A comparison of alternative models of prescription drug utilization
Authors: Grootendorst Paul V.
Published: May 2007

The two‐part estimation technique has been advocated for estimating models using individual level health care utilization data characterised by a large proportion of non‐consumption and small proportions of heavy users. This paper compares the two‐part model to several other estimators, including the Poisson, negative binomial and 'zero altered' negative binomial models on the basis of within‐sample forecasting accuracy and non‐nested model selection tests. The empirical model estimates the differential effect of the removal of copayments for prescription medicines on the prescription drug utilization by older adults with differing levels of health status. The two‐part estimator of this model is found to dominate the competitors. Results from this model indicate that utilization increases appear to be higher among individuals with lower levels of health status.
Design and evaluation of an augmented reality welding helmet
Authors: Park M. , Schmidt L. , Schlick C. , Luczak H.
Published: May 2007

The article describes the development and ergonomic evaluation of an augmented reality (AR) welding helmet. The system provides an augmented user interface with supporting information relevant to the welding process. The experimental studies focused on hand–eye coordination of welders and nonwelders with two prototypes of the augmented reality welding helmet. The first prototype operated at 16 frames per second, whereas the second, improved version had 20 frames per second. In addition, the hand–eye coordination while wearing the welding helmet with video see‐through head‐mounted display was compared to a performance with natural vision, without any helmet. Experimental results showed significant influence of helmet and occupation on hand–eye coordination. Subjective assessment revealed better rating for stereo perception for the system with the higher frame rate, whereas no significant difference in performance was found between the two frame rates. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 317–330, 2007.
Integrating ergonomics into engineering: Empirical evidence and implications for the ergonomists
Authors: Broberg Ole
Published: May 2007

Engineering design is a strong determinant of workplace ergonomics. A survey among 680 engineers in 20 Danish enterprises indicated that engineers are not aware that they influence the work environment of other people. Ergonomics had a low rating among engineers, perhaps because neither management nor safety organizations expressed any expectations in this area. The study further indicated that effects of ergonomics training in engineering schools were very limited. The engineering cultures in enterprises, together with other organizational factors, are suggested to be of greater importance than the professional training. The implications for industrial ergonomists might be an acknowledgement of the role as change agent when trying to integrate ergonomics into engineering. In doing so, they need also to acknowledge that engineers are widely different. They have different backgrounds and a “sensitivity” to ergonomics depending on their current engineering domain, tasks, organizational position, and the industrial branch of their organization. © 2007 Wiley Periodicals, Inc. Hum Factors Man 17: 353–366, 2007.
Modeling of water absorption induced cracks in resin‐based composite supported ceramic layer structures
Authors: Huang Min , Thompson V. P. , Rekow E. D. , Soboyejo W. O.
Published: May 2007

Cracking patterns in the top ceramic layers of the modeled dental multilayers with polymer foundation are observed when they are immersed in water. This article developed a model to understand this cracking mechanism. When water diffuses into the polymer foundation of dental restorations, the foundation will expand; as a result, the stress will build up in the top ceramic layer because of the bending and stretching. A finite element model based on this mechanism is built to predict the stress build‐up and the slow crack growth in the top ceramic layers during the water absorption. Our simulations show that the stress build‐up by this mechanism is high enough to cause the cracking in the top ceramic layers and the cracking patterns predicted by our model are well consistent with those observed in experiments on glass/epoxy/polymer multilayers. The model is then used to discuss the life prediction of different dental ceramics. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Alterations of human acellular tissue matrix by gamma irradiation: Histology, biomechanical property, stability, in vitro cell repopulation, and remodeling
Authors: Gouk Sok‐Siam , Lim Tit‐Meng , Teoh Swee‐Hin , Sun Wendell Q.
Published: May 2007

AlloDerm, a processed acellular human tissue matrix, is used in a number of surgical applications for tissue repair and regeneration. In the present work, AlloDerm serves as a model system for studying gamma radiation‐induced changes in tissue structure and stability as well as the effect of such changes on the cell–matrix interactions, including cell repopulation and matrix remodeling. AlloDerm tissue matrix was treated with 2–30 kGy gamma irradiation at room temperature. Gamma irradiation reduced the swelling of tissue matrix upon rehydration and caused significant structural modifications, including collagen condensation and hole formation in collagen fibres. The tensile strength of AlloDerm increased at low gamma dose but decreased with increasing gamma dosage. The elasticity of irradiated AlloDerm was reduced significantly. Calorimetric study showed that gamma irradiation destabilized the tissue matrix, resulting in greater susceptibility to proteolytic enzyme degradation. Although gamma irradiation did not affect in vitro proliferation of fibroblast cells, it promoted tissue degradation upon cell repopulation and influenced synthesis and deposition of new collagen. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Decreased focal inflammatory response by G‐CSF may improve stroke outcome after transient middle cerebral artery occlusion in rats
Authors: Sehara Yoshihide , Hayashi Takeshi , Deguchi Kentaro , Zhang Hanzhe , Tsuchiya Atsushi , Yamashita Toru , Lukic Violeta , Nagai Makiko , Kamiya Tatsushi , Abe Koji
Published: May 2007

Recent studies have shown that administration of granulocyte colony‐stimulating factor (G‐CSF) is neuroprotective. However, the precise mechanisms of the neuroprotective effect of G‐CSF are not entirely known. We carried out 90‐min transient middle cerebral occlusion (tMCAO) of rats. The rats were injected with vehicle or G‐CSF (50 μg/kg) immediately after reperfusion and sacrificed 8, 24, or 72 hr later. 2,3,5‐Triphenyltetrazolium chloride (TTC) staining was carried out using brain sections of 72 hr, and immunohistochemistry was carried out with those of 8, 24, and 72 hr. TTC‐staining showed a significant reduction of infarct volume in the G‐CSF‐treated group (**P < 0.01). Immunohistochemistry showed a significant decrease of the number of cells expressing tumor necrosis factor‐α (TNF‐α) at 8–72 hr, transforming growth factor‐β (TGF‐β) and inducible nitric oxide synthase (iNOS) at 24 and 72 hr after tMCAO in the peri‐ischemic area (*P < 0.05 each). Our data suggest that the suppression of inflammatory cytokines and iNOS expression may be one mechanism of neuroprotection by G‐CSF. © 2007 Wiley‐Liss, Inc.
A dynamic key management solution to access hierarchy
Authors: Zou Xukai , Karandikar Yogesh , Bertino Elisa
Published: May 2007

Hierarchical access control (HAC) has been a fundamental problem in computer and network systems. Since Akl and Taylor proposed the first HAC scheme based on number theory in 1983, cryptographic key management techniques for HAC have appeared as a new and promising class of solutions to the HAC problem. Many cryptographic HAC schemes have been proposed in the past two decades. One common feature associated with these schemes is that they basically limited dynamic operations at the node level. In this paper, by introducing the innovative concept of ‘access polynomial’ and representing a key value as the sum of two polynomials in a finite field, we propose a new key management scheme for dynamic access hierarchy. The newly proposed scheme supports full dynamics at both the node level and user level in a uniform yet efficient manner. Furthermore, the new scheme allows access hierarchy to be a random structure and can be flexibly adapted to many other access models such as ‘transfer down’ and ‘depth‐limited transfer’. Copyright © 2007 John Wiley & Sons, Ltd.
Cross‐layer design to improve elastic traffic performance in WLANs
Authors: Lohier Stephane , Doudane Yacine Ghamri , Pujolle Guy
Published: May 2007

In this paper, we are interested in improving TCP flow performance when a short loss of 802.11 signal leads to losing segments and triggers inappropriately TCP congestion control mechanisms. A set of measurements in a common wireless environment with signal losses due to mobility or interference is made to highlight the distinct MAC and TCP loss recovery levels and the lack of interactions between them. Initially, we demonstrate the interest of adapting the 802.11 MAC layer Retry Limit parameter in the case of signal losses due to distance or obstacles (mobility). Thus, a first‐level loss differentiation algorithm (LDA) acting at the MAC layer is proposed to improve TCP flow performance in the case of segment losses due to mobility. Hence, for a signal failure, the MAC layer reacts consequently by dynamically adapting the Retry Limit parameter. This adaptation allows avoiding a costly end‐to‐end TCP loss recovery. Segment losses due to interference are differentiated from those due to congestion through the use of a second‐level LDA. The latter is a cross‐layer LDA acting at the TCP layer but using a specific 802.11 parameter, the AckFailureCount, to realize the targeted loss differentiation. The TCP NewReno version is then adapted in order to integrate the cross‐layer LDA results and to avoid reducing the TCP congestion window unsuitably. The efficiency and completeness of a solution integrating both LDA schemes is then discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Network models for maximization of heat transfer under weight constraints
Authors: Bhargav S. , Duffin R. J.
Published: May 2007

Of concern is a network in which the conductance of certain branches are variable. The problem posed is the maximization of the joint conductance subject to a bound on the lρ norm of the variable conductances. It is shown that at an optimum state the conductance of a variable branch is proportional to the 2/(ρ+1) power of the current through the branch. This relation together with a dual variational principle leads to a “duality inequality” giving sharp upper and lower estimates of the maximum joint conductance. Such a network serves as a discrete model for a cooling fin subject to a weight limitation. Thus the model shows what analogous properties should hold for the cooling fin.