bluuebunny/crossref_metadata_2025 huggingface dataset:
Developments in asbestos cancer risk assessment
Authors: Silverstein Michael A. , Welch Laura S. , Lemen Richard
Published: September 2009

Background

Efforts have been made for 25 years to develop asbestos risk assessments that provide valid information about workplace and community cancer risks. Mathematical models have been applied to a group of workplace epidemiology studies to describe the relationships between exposure and risk. EPA's most recent proposed method was presented at a public meeting in July 2008.

Methods

Risk assessments prepared by USEPA, OSHA, and NIOSH since 1972 were reviewed, along with related literature.

Results and Conclusions

None of the efforts to use statistical models to characterize relative cancer potencies for asbestos fiber types and sizes have been able to overcome limitations of the exposure data. Resulting uncertainties have been so great that these estimates should not be used to drive occupational and environmental health policy. The EPA has now rejected and discontinued work on its proposed methods for estimating potency factors. Future efforts will require new methods and more precise and reliable exposure assessments. However, while there may be genuine need for such work, a more pressing priority with regard to the six regulated forms of asbestos and other asbestiform fibers is to ban their production and use. Am. J. Ind. Med. 52:850–858, 2009. © 2009 Wiley‐Liss, Inc.
Influence of the oxidation and acetylation of banana starch on the mechanical and water barrier properties of modified starch and modified starch/chitosan blend films
Authors: Zamudio‐Flores Paul Baruk , Torres Apolonio Vargas , Salgado‐Delgado René , Bello‐Pérez Luis Arturo
Published: September 2009

Banana starch was oxidized at three different levels and afterwards acetylated. The double‐modified starch was used for film preparation with the addition of chitosan. The physical, mechanical, and barrier properties were tested. The oxidation level increased the moisture content of the film, but the acetylation and the addition of chitosan decreased this characteristic. The oxidation level increased the whiteness of the film, but the second modification (acetylation) and the addition of chitosan to the blend did not affect this parameter. The solubility increased with the temperature and the oxidation level but decreased with the storage time of the film. The oxidation increased and the acetylation reduced the solubility with respect to the native starch film. The dual modification produced a solubility value less than that of its oxidized counterpart, and the addition of chitosan produced the highest solubility value. The addition of chitosan increased the tensile strength of the film, and the effect was higher with the oxidation level and longest storage time. The addition of chitosan produced a higher elongation value than that of its double‐modified film, but at the longest storage time, this parameter decreased. The water vapor permeability increased with the oxidation level because of the hydrophilic character, but the acetylation reduced this parameter because the acetylation increased the hydrophobic character of the starch due to the ester group. Films prepared with the double‐modified banana starch and the addition of chitosan had some improved physical, mechanical, and barrier properties, and they may be used in specific applications. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of the particle size on the viscoelastic glass transition of silica‐filled polystyrene
Authors: Mortezaei Mehrzad , Famili Mohammad Hossein Navid , Kokabi Mehrdad
Published: September 2009

The effects of the filler particle size and volume fraction on the viscoelastic glass‐transition temperature of filled polymers were investigated with polystyrene containing silica nanoparticles. The samples were prepared by a solution‐mixing method to obtain a better dispersion of silica particles. Dynamic rheometry was used to study the viscoelastic behavior of these materials in the melt state. The addition of silica particles broadened the elastic modulus and increased its magnitude in the glass‐transition region. Also, the magnitude of the loss modulus and loss tangent peaks decreased. These phenomena were intensified by a reduction of the silica particle size, which increased filler–filler interactions. Furthermore, with a reduction in the size of the silica particles, the glass‐transition temperature of the filled polymer increased simultaneously with an increase in the interfacial layer volume fraction, which was related to an increase in the total surface area of the silica particles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effects of divalent cations, seawater, and formation brine on positively charged polyethylenimine/dextran sulfate/chromium(III) polyelectrolyte complexes and partially hydrolyzed polyacrylamide/chromium(III) gelation
Authors: Johnson Stephen , Trejo Julieta , Veisi Masoumeh , Willhite G. Paul , Liang Jenn‐Tai , Berkland Cory
Published: September 2009

Polyacrylamide crosslinked with Cr(III) is a common blocking agent that is injected into oil reservoirs to shut off the water flow to features such as fractures and high‐permeability rock to improve the volumetric sweep efficiency during water flooding. This technique is limited to situations where enough gelant can be injected to fill the high‐permeability zones before gelation occurs. Cr(III) may be encapsulated with a high entrapment efficiency in self‐assembling polyelectrolyte complex nanoparticles with effective diameters of about 100–200 nm and formed by the mixture of polyethylenimine and dextran sulfate in nonstoichiometric amounts. The electrostatic interaction between the polyelectrolytes and the Cr(III) is reversible, but diffusion out of the nanoparticles is retarded, and this results in a delay in gelation from minutes or hours to several days in deionized water. Produced and injection waters often contain salts at concentrations comparable to seawater. The effects of these salts were investigated, and we found that the delay in gelation was further extended to as much as 35 days at 40°C and 35 h at 80°C in the presence of divalent ions at seawater concentrations, either alone or in a field brine or seawater; this greatly increases their potential utility. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Creaming of skim natural rubber latex with chitosan derivatives
Authors: Kongkaew Chaveewan , Loykulnant Surapich , Chaikumpollert Oraphin , Suchiva Krisda
Published: September 2009

To recover residual rubber from skim natural rubber (SNR) latex, a novel method was developed on the basis of the use of water‐soluble chitosan derivatives. An anionic chitosan derivative, N,O‐carboxymethyl chitosan (CMCh), and a cationic chitosan derivative, N‐(2‐hydroxy)propyl‐3‐trimethylammonium chitosan chloride (HTACh), were prepared. It was found that the creaming process could be achieved with both chitosan derivatives. By the addition of 7.34–10.3‐g/L CMCh, SNR latex was almost completely creamed, and no coagulation of SNR particles in the cream phase occurred. In the case of HTACh, the creaming process was achieved with a lower concentration (<3.70 g/L) than in the case of CMCh, but the size of SNR particles in the cream phase was larger. Solid‐state 13C‐NMR, thermogravimetric analysis, and ζ potential measurement results provided evidence that the creaming of SNR latex with CMCh and HTACh was controlled by the depletion flocculation and adsorption mechanisms, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Copolymerization of 1‐oxo‐2,6,7‐trioxa‐1‐phorsphabicyclo[2,2,2]oct‐4‐yl methyl acrylate and (10‐oxo‐10‐hydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐yl) methyl acrylate with styrene and their thermal degradation characteristics
Authors: Yan Li , Zheng Yu Bin , Liang Xiaobin , Ma Qian
Published: September 2009

Two phosphorus‐containing acrylates of 1‐oxo‐2,6,7‐trioxa‐1‐phorsphabicyclo[2,2,2]oct‐4‐yl methyl acrylate and (10‐oxo‐10‐hydro‐9‐oxa‐10λ5‐phosphaphenanthrene‐10‐yl) methyl acrylate were free‐radical‐copolymerized with styrene (St). The r1 reactivity ratio values (related to the novel acrylates) were 0.342 and 0.225, respectively, and the r2 reactivity ratio values (related to St) were 0.432 and 0.503, respectively. The thermal stability of the copolymers was tested by thermogravimetric analysis (TGA) in N2 or air, and the ignitability was tested by measurements of UL‐94 vertical combustion tests and the limiting oxygen index. The results of TGA and combustion tests indicated that the effect of flame retardancy was determined by the nature of the phosphorus‐containing substituent. Compared with the 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide based group, the 1‐oxo‐2,6,7‐trioxa‐1‐phorsphabicyclo[2,2,2]oct‐4‐yl methol based group could enhance the ability of char formation with an antidripping effect. It is concluded that phosphorus‐containing acrylates are potential flame‐retarding monomers for styrenic polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Structure and properties of cellulose fibers from ionic liquids
Authors: Cai Tao , Zhang Huihui , Guo Qinghua , Shao Huili , Hu Xuechao
Published: September 2009

1‐Butyl‐3‐methylimidazolium chloride ([BMIM]Cl) was used as a solvent for cellulose, the rheological behavior of the cellulose/[BMIM]Cl solution was studied, and the fibers were spun with a dry‐jet–wet‐spinning process. In addition, the structure and properties of the prepared cellulose fibers were investigated and compared with those of lyocell fibers. The results showed that the cellulose/[BMIM]Cl solution was a typical shear‐thinning fluid, and the temperature had little influence on the apparent viscosity of the solution when the shear rate was higher than 100 s−1. In addition, the prepared fibers had a cellulose II crystal structure just like that of lyocell fibers, and the orientation and crystallinity of the fibers increased with the draw ratio increasing, so the mechanical properties of the fibers improved. Fibers with a tenacity of 4.28cN/dtex and a modulus of 56.8 cN/dtex were prepared. Moreover, the fibers had a smooth surface as well as a round and compact structure, and the dyeing and antifibrillation properties of the fibers were similar to those of lyocell fibers; however, the color of these dyed fibers was brighter than that of lyocell fibers. Therefore, these fibers could be a new kind of environmentally friendly cellulose fiber following lyocell fibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nanoparticle effects on structure and properties of polypropylene meltblown webs
Authors: Hegde Raghavendra R. , Bhat Gajanan S.
Published: September 2009

The effect of nanoclay additive on the structure, morphology, and mechanical properties of polypropylene meltblown webs is reported here for the first time. Effect of nanoclay on the meltblown processing, resultant fiber web structure, and properties are discussed. Combination of wide‐angle x‐ray diffraction, differential scanning calorimetry, and transmission electron microscopy were used to determine the nature of clay dispersion in the polypropylene fiber matrix and resultant morphology. Transmission electron microscopy micrographs revealed nanolevel dispersion of the additive in the fiber web. Clay additive did not offer any benefit as far as the mechanical properties of the meltblown web are concerned. Meltblown web samples with nanoclay had higher variability in web structure, high air permeability, high stiffness, and lower mechanical properties. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis, characterization, and metal adsorption properties of tannin–phenol–formaldehyde resins produced using tannin from dried fruit of Terminalia chebula (Aralu)
Authors: Arasaretnam S. , Karunanayake L.
Published: September 2009

In this study, tannin extracted from Terminalia chebula (Aralu) was used to produce tannin–phenol–formaldehyde resins. They were produced to obtain resins with different tannin to phenol ratio in an attempt to optimize the ion exchange capacities of resins produced. The resins made were sulfonated to improve their properties further. Bivalent cations, such as Zn2+, Pb2+, Ca2+, Mg2+, and Cu2+, were used to estimate the adsorption properties of both unsulfonated and sulfonated resins. The glass transitions of representative resins were estimated using differential scanning calorimeter thermograms. Fourier transform infrared spectroscopic analysis was used to gauge changes on resins by sulfonation and adsorption of cations. The glass transition values of unsulfonated, sulfonated, and metal‐adsorbed sulfonated resins showed a similar increasing trend with the increase of phenol content in the resin. The glass transition temperature values reach a plateau beyond the tannin/phenol ratio of 1 : 0.5, indicating the formation of large molar masses facilitating entanglements beyond that ratio. The phenol ratio of 1 : 0.5 has shown the highest adsorption capacity for all the metal ions used. The highest adsorption capacity was shown for sulfonated tannin–phenol–formaldehyde resin with the tannin/phenol ratio of 1 : 0.5 for Pb2+, which is 0.610 meq/g. The adsorption equilibrium data obtained using the column technique were found fitting Freundlich isotherm. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of varying surface hydrophobicity of chitosan membranes on the adsorption and activity of lipase
Authors: Deng Hong‐Tao , Wang Juan‐Juan , Liu Zhong‐Yang , Ma Miao
Published: September 2009

The hydrophobic surface modification of chitosan membranes was performed using the amidating reaction of amino groups on a membrane surface with stearic acid activated by 1‐ethyl‐3‐(3‐dimethylaminopropyl)‐carbodiimide hydrochloride (EDC) and N‐hydroxysuccinimide (NHS). The varying surface hydrophobicity of chitosan membranes was achieved by changing the degree of amidation and evaluated by the water contact angle analysis and the adsorption experiment of the hydrophobic dye, Rose Bengal. The effects of the surface hydrophobicity of chitosan membranes on the adsorption behaviors, activity and stability of Candida rugosa lipases were investigated. The experimental results suggested that the increased surface hydrophobicity of chitosan membranes improved the adsorption capacity and activity of the immobilized lipase. The modified chitosan membranes with 30.36% amidation exhibited the maximum activity retention of 83.87%. In addition, a desirable thermal stability was also achieved for the adsorbed lipase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Nanocomposites made from cellulose nanocrystals and tailored segmented polyurethanes
Authors: Auad Maria L. , Mosiewicki Mirna A. , Richardson Tara , Aranguren Mirta I. , Marcovich Norma E.
Published: September 2009

The effect of the addition of microcrystalline cellulose nanofibers into linear segmented polyurethanes (SPU) was investigated. The polymers were synthesized with 4,4‐methylene‐bisphenyldiisocyanate (MDI) and poly(tetramethyleneglycol) (PTMG) with 1,4‐butanediol (BD) as chain extender. The nanocrystals were introduced during the PU polymerization, which resulted in cellulose nanofibrils covalently linked to the polymer. The interactions between the cellulose nanofibrils and the matrix lead to interesting changes in the behavior of the PU, with the hard segment (HS) phase being more affected by these interactions. SPUs with different contents of HS were synthesized to better understand these effects (23 to 45 wt %). Thermal, thermo‐mechanical and mechanical characterization of the nanocomposites were performed. In general, the nanocellulose favored the phase separation between the soft and hard domains generating an upward shift in the melting temperatures of the crystalline phases, an increase in the Young's modulus and a decrease in deformation at break. Comparison of the unfilled polymer responses and that of the nanocomposites showed that by increasing cellulose content, increased dynamic storage and tensile modulus as well as melting temperatures and enthalpy of melting of the soft domains can be achieved. Addition of cellulose during the polymerization essentially erased the potential shape memory behavior originally displayed by some of the SPU. However, a sample prepared by adding the cellulose nanocrystals after the reaction showed that the mechanical properties were still improved, while the shape memory behavior of the polymer was preserved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Hydrogel–silver nanoparticle composites: A new generation of antimicrobials
Authors: Varaprasad K. , Mohan Y. Murali , Ravindra S. , Reddy N. Narayana , Vimala K. , Monika K. , Sreedhar B. , Raju K. Mohana
Published: September 2009

Design of consistant and eco‐friendly methods for the synthesis of silver nanoparticles (AgNPs) is a significant forward direction in the field of application of antibacterial bionanotechnology. One among the available options is hydrogel templates, which are highly useful to achieve this goal. This investigation involves the development of poly(acrylamide)/poly(vinyl alcohol) hydrogel–silver nanocomposites (HSNCs) to achieve AgNPs of ∼2–3 nm size in gel networks. The nanocomposite synthesis process is quite convenient, direct, and very fast, and the obtained hydrogel AgNP composites can be used for antibacterial and wound dressing applications. All the nanocomposite aqueous solutions have shown absorption peaks at 420 nm in UV–visible absorption spectrum corresponding to the Plasmon absorbance of AgNPs. X‐ray diffraction spectrum of the HSNC exhibited 2θ values matching with silver nanocrystals. Transmission electron microscopy images of nanocomposites represent discrete AgNPs throughout the gel networks in the range of 2–3 nm. The developed nanocomposites were evaluated for antibacterial application on E. coli. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Liquefaction of wood, synthesis and characterization of liquefied wood polyester derivatives
Authors: Kunaver Matjaž , Jasiukaityte Edita , Čuk Nataša , Guthrie James T.
Published: September 2009

Liquefaction of Central‐European softwoods meal was performed using a mixture of diethylene glycol and glycerol and a minor addition of p‐toluenesulfonic acid as a catalyst. The liquefied wood was used as a replacement of a certain amount of the polyhydroxy alcohol in the polyester synthesis, enabled by the large number of hydroxyl groups that were available in the liquefied wood. Three different polyesters were synthesized by using adipic acid and phthalic acid anhydride as reagents. The products were characterized using FTIR, GPC/SEC, and viscosity measurements. The polyesters have hydroxyl values that were reduced due to esterification, from 1043 mg KOH/g of the liquefied wood to 400–800 mg KOH/g. Polyhydroxyl alcohols (22–23%) in the polyester formulations were replaced by wood derivatives. Such saturated polyesters are suitable for further use in polyurethane foam production. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Benzenesulfonamidoquinolino‐β‐cyclodextrin as a Cell‐Impermeable Fluorescent Sensor for Zn2+
Authors: Zhang Ning , Chen Yong , Yu Miao , Liu Yu
Published: September 2009

A water‐soluble benzenesulfonamidoquinolino‐β‐cyclodextrin has been successfully synthesized in 30 % yield by incorporating a N‐(8‐quinolyl)‐p‐aminobenzenesulfonamide (HQAS) group to β‐cyclodextrin through a flexible linker. This compound exhibits a good fluorescence response in the presence of Zn2+ in water but gives poor fluorescence responses with other metal ions commonly present in a physiological environment under similar conditions. Fluorescence microscopic and two‐dimensional NMR experiments showed that benzenesulfonamidoquinolino‐β‐cyclodextrin could bind to the loose bilayer membranes. As a result, benzenesulfonamidoquinolino‐β‐cyclodextrin was found to act as an efficient cell‐impermeable Zn2+ probe, showing a specific fluorescent sensing ability to Zn2+‐containing damaged cells whilst exhibiting no response in the presence of healthy cells.
Reasons women chartered accountants leave public accounting firms prior to achieving partnership status: A qualitative analysis
Authors: Wallace Peggy
Published: September 2009

This paper reports on the stories told by 13 Canadian women Chartered Accountants (CAs)—why they pursued the CA designation and why they chose to leave public accounting firms. Their stories provide deeper insights into the previously reported reasons for female CAs leaving firms that are often reported within broad categories. Work‐family issues received limited attention in the participants' stories. Two major themes emerged: the absence of stated aspirations/desire to become a partner; and frustrations with the intrinsic and monetary value of services delivered by public accounting firms. The implications of these findings for the profession and public accounting firms are examined and future research directions are discussed. Copyright © 2009 ASAC. Published by John Wiley & Sons, Ltd.
An examination of gender influences in career mentoring
Authors: Leck Joanne , Orser Barbara , Riding Allan
Published: September 2009

This study draws on the Theory of Planned Behaviour to examine the role of gender in the decision to be mentored. Contrary to expectations, men and women employ similar decision criteria in the decision to seek a mentor. The primary driver for seeking a mentor was to obtain psychosocial support, including personal support, acceptance, having a confidant, being trusted and friendship. Men were more likely than women to seek a mentor when they valued increased autonomy. The implications of the findings for protégés, mentors and career development professionals are noted. Copyright © 2009 ASAC. Published by John Wiley & Sons, Ltd.
Preparation, Characterization and Adsorption Mechanism of Cu(II) onto Protonated Rubber Leaf Powder
Authors: Hanafiah Megat Ahmad Kamal Megat , Ngah Wan Saime Wan
Published: September 2009

The adsorption of Cu(II) onto HCl treated rubber leaf powder (HHBL) was investigated in batch and column studies. The adsorbent was characterized by spectroscopic and quantitative analyses in order to understand the mechanism of copper adsorption. HHBL is mesoporous in nature as indicated by Bruneuer, Emmett and Teller (BET) analysis, and has various kinds of functional groups such as Si‐OH, ROH, RCOOH, RCOO–, RNH2, C‐O‐C and aromatic rings as detected by Fourier transform infrared (FTIR) spectroscopy. Copper adsorption was confirmed by scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy (EDS). The equilibrium process was described well by the Langmuir isotherm model, and a maximum adsorption capacity of 8.39 mg/g was recorded for the smallest adsorbent size (<180 μm). The two main adsorption mechanisms involved were ion exchange and complexation. The fixed bed column study demonstrated satisfactory applicability of HHBL in removing Cu(II) from aqueous solutions.
B7‐1/2, but not PD‐L1/2 molecules, are required on IL‐10‐treated tolerogenic DC and DC‐derived exosomes for in vivo function
Authors: Ruffner Melanie A. , Kim Seon Hee , Bianco Nicole R. , Francisco Loise M. , Sharpe Arlene H. , Robbins Paul D.
Published: September 2009

Costimulatory molecules, such as B7‐1/2 and PD‐L1/2 play an important role in the function of APC. The regulation of the surface levels of costimulatory molecules is one mechanism by which APC maintain the balance between tolerance and immunity. We examined the contributions of B7‐1/2 and PD‐L1/2 to the function of IL‐10‐treated, immunosuppressive DC as well as therapeutic exosomes derived from these DC. IL‐10 treatment of DC significantly downregulated surface expression of MHC II, B7‐1, B7‐2, and decreased levels of MHC I and PD‐L2. IL‐10 treatment of DC resulted in a modified costimulatory profile of DC‐secreted exosomes with a reduction in B7‐1, PD‐L1 and PD‐L2. We further demonstrate that absence of B7‐1 or B7‐2 on donor DC results in a loss of ability of IL‐10‐treated DC and their exosomes to suppress the delayed‐type hypersensitivity response, whereas IL‐10‐treated DC deficient in PD‐L1/2 as well as their secreted exosomes retained the ability to suppress delayed‐type hypersensitivity responses. We conclude that B7‐1 and B7‐2, but not PD‐L1 and PD‐L2, on IL‐10‐treated DC and DC‐derived exosomes play a critical role in immunosuppressive functions of both DC and exosomes.
Highly Selective Electrophile‐Induced Cascade Reactions between o‐Alkynylbenzaldehydes and Styrene Oxides Leading to the Formation of 1‐Naphthyl Ketones
Authors: Patil Nitin T. , Konala Ashok , Singh Vipender , Reddy Vaddu V. N.
Published: September 2009

An efficient method for the synthesis of naphthalene derivatives through reaction of o‐alkynylbenzaldehydes and styrene oxides in the presence of molecular iodine was developed. The reaction involves Meinwald rearrangement of styrene oxides to form the corresponding aryl acetaldehydes. The enol forms of aryl acetaldehydes might undergo [4+2] benzannulation reactions with iodinated benzopyrilium ions, formed in situ from o‐alkynylbenzaldehydes and iodine, to afford 1‐naphthyl ketones. The reaction was found to be highly selective, and of two possible products, only one was formed. Mechanistic aspects are discussed.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A determination of submicromolar concentrations of glycine in periaqueductal gray matter microdialyzates using capillary zone electrophoresis with contactless conductivity detection
Authors: Tůma Petr , Soukupová Marie , Samcová Eva , Štulík Karel
Published: September 2009

CE with contactless conductivity detection has been used to determine the glycine neurotransmitter in periaqueductal gray matter (PAG) of rats. The LOD for glycine has been decreased to a value of 0.2 μM by adding 75% v/v of ACN to the samples and increasing the sample zone introduced to a value of 20% of the overall capillary length. The repeatabilities of the analyte migration times and the zone areas amount to 2.1 and 2.7%, respectively. The optimized CE/contactless conductivity detection method makes it possible to determine the micromolar concentrations of glycine in PAG microdialyzates without the necessity of sample derivatization. It follows from a pharmacological study that a local inflammation initiated by an application of carrageenan increased the glycine concentration in the rat PAG seven times, compared with a control. The glycine level in PAG can be decreased and the pain suppressed by administering paracetamol.
Torsional balance as new design criterion for asymmetric structures with energy dissipation devices
Authors: Almazán José L. , de la Llera Juan C.
Published: September 2009

Lateral–torsional coupling in asymmetric‐plan buildings leads to correlated translations and rotations of the building plan, which generate uneven distributions of deformation demand among resisting planes. The deformation demand of a resisting plane depends on the relative magnitude of the plan translation and rotation and on the correlation between the two signals. Thus, small rotations highly correlated with building translation may lead to significantly different deformations of the resisting planes at the building edges. Consequently, the use of supplemental dampers is intended not only to reduce the magnitude of the plan translation and rotation, but also the correlation between these motions. For the sake of simplicity, linear viscous dampers are used in this investigation, which properly located in plan lead to a minimum response of the geometric center, thus achieving the same mean‐square value of the displacements at the building edges. Mathematically, this condition may be understood as creating zero correlation between the translations and rotation at the geometric center of the plan, which represents an uncoupling in the mean‐square sense. Results show that the optimal damper location depends on the static eccentricity and frequency ratio of the bare structure, the total amount of supplemental damping considered, and the frequency content of the excitation. Through a final 6‐story model example, the torsional balance concept is demonstrated to work on multistory buildings subjected to bidirectional ground motions. Copyright © 2009 John Wiley & Sons, Ltd.
HPV‐positive/p16‐positive/EBV‐negative nasopharyngeal carcinoma in white North Americans
Authors: Maxwell Jessica H. , Kumar Bhavna , Feng Felix Y. , McHugh Jonathan B. , Cordell Kitrina G. , Eisbruch Avraham , Worden Francis P. , Wolf Gregory T. , Prince Mark E. , Moyer Jeffrey S. , Teknos Theodoros N. , Chepeha Douglas B. , Stoerker Jay , Walline Heather , Carey Thomas E. , Bradford Carol R.
Published: September 2009

Background

Human papillomavirus (HPV) has been detected in keratinizing nasopharyngeal carcinomas (NPCs); however, the relationship between HPV and Epstein–Barr virus (EBV) among whites with nonkeratinizing NPCs remains unclear. The HPV, p16, and EBV status was examined in current University of Michigan patients with NPC.

Methods

From 2003 to 2007, 89 patients, 84 with oropharyngeal cancer (OPC) and 5 with NPC, were enrolled in an organ‐sparing trial. Biopsy tissues from all 89 patients were evaluated for HPV and p16 expression. A separate HPV analysis of the 84 OPC patients is in progress. Among the patients with NPC, tumor tissue was also analyzed for EBV‐encoded RNA (EBER).

Results

Five of 89 patients (5.6%) had NPC, all with nonkeratinizing histology. The 4 white patients with NPC were HPV(+) (subtype‐16, subtype‐18 [2 patients], and subtype‐59)/p16(+)/EBER(‐). One Asian patient with NPC had an HPV(‐)/p16(‐)/EBER(+) NPC tumor that developed distant metastases.

Conclusion

We postulate that HPV may be the etiologic factor in some EBV‐negative, nonkeratinizing NPCs among whites. © 2009 Wiley Periodicals, Inc. Head Neck, 2010
Mixing processes in the Amazon River at the confluences of the Negro and Solimões Rivers, Encontro das Águas, Manaus, Brazil
Authors: Laraque Alain , Guyot Jean Loup , Filizola Naziano
Published: September 2009

The confluence of the rivers Negro and Solimões gives birth to the Amazon River near Manaus (Brazil). At their confluence, these two rivers with their very different physical and geochemical characteristics provide an interesting example of the mixing of waters along a reach of approximately one‐hundred kilometres. The purpose of this article is to describe and explain the spatial configuration of the Solimões–Negro Rivers mixing zone, based on a systematic sampling survey carried out in September 1997, using a special sampler and an acoustic Doppler current profiler (Acoustic Doppler Current Profiler). The waters of the Negro River differ from those of the Solimões River in their lower velocity (0·3 vs 1 m s−1), conductivity (8 vs 80 µS cm−1 at 25 °C), turbidity (5 vs 80 NTU), pH (5·5 vs 7·0) and higher temperatures (by 1 °C). Due to their higher density, the waters of the Solimões River slide under those of the Negro River, and consequently, Negro River waters are located at the surface, close to the left bank, and Solimões River waters are located at the bottom, close to the right bank. The contact between the waters of the two rivers changes from a clearly defined vertical boundary to a diffuse horizontal boundary, as they move downstream. The complete mixing process takes more than 30 h and 100 km. Copyright © 2009 John Wiley & Sons, Ltd.
Diminished groundwater recharge and circulation relative to degrading riparian vegetation in the middle Tarim River, Xinjiang Uygur, Western China
Authors: Pang Zhonghe , Huang Tianming , Chen Yaning
Published: September 2009

Riparian vegetation in the middle Tarim River is being degenerated, and groundwater in the riparian system is a key factor controlling this process. Vegetation degeneration is related to the reduced inflow from the upstream, reduced recharge to riparian groundwater, lowered water table and increased salinity of the groundwater system. Systematic chemical and isotopic sampling of river water and groundwater transects perpendicular to the river show that riparian groundwater is fed by the river. River water picks up salts from the river bed and/or from irrigation returns as it flows downstream, and groundwater from riverbank sediments mirror this pattern. Mineral dissolution and evapotranspiration are the main mechanisms of salt accumulation in groundwater. Reduced recharge from the river has resulted in a distinctive zoning pattern in groundwater salinity. Groundwater residence times derived from tritium contents indicate that the extent of modern recharge (since the 1960s) is limited to approximately 1500 m from the riverbank in the middle reaches of the Tarim River. Vegetation grows better in habitats with modern groundwater than in other areas. The embankment built in 2001 along one side of the Tarim River appears to have reduced groundwater recharge, causing the water table to drop and ecosystem to degenerate. Copyright © 2009 John Wiley & Sons, Ltd.
What the eyes already ‘know’: using eye movement measurement to tap into children's implicit numerical magnitude representations
Authors: Heine Angela , Thaler Verena , Tamm Sascha , Hawelka Stefan , Schneider Michael , Torbeyns Joke , De Smedt Bert , Verschaffel Lieven , Stern Elsbeth , Jacobs Arthur M.
Published: September 2009

To date, a number of studies have demonstrated the existence of mismatches between children'simplicitandexplicitknowledge at certain points in development that become manifest by their gestures and gaze orientation in different problem solving contexts. Stimulated by this research, we used eye movement measurement to investigate the development of basic knowledge about numerical magnitude in primary school children. Sixty‐six children from grades one to three (i.e. 6–9 years) were presented with two parallel versions of a number line estimation task of which one was restricted to behavioural measures, whereas the other included the recording of eye movement data. The results of the eye movement experiment indicate a quantitative increase as well as a qualitative change in children's implicit knowledge about numerical magnitudes in this age group that precedes the overt, that is, behavioural, demonstration of explicit numerical knowledge. The finding that children's eye movements reveal substantially more about the presence of implicit precursors of later explicit knowledge in the numerical domain than classical approaches suggests further exploration of eye movement measurement as a potential early assessment tool of individual achievement levels in numerical processing. Copyright © 2009 John Wiley & Sons, Ltd.
Metabolic fate of ultratrace levels of GeCl4 in the rat and in vitro studies on its basal cytotoxicity and carcinogenic potential in Balb/3T3 and HaCaT cell lines†
Authors: Sabbioni E. , Fortaner S. , Bosisio S. , Farina M. , Del Torchio R. , Edel J. , Fischbach M.
Published: September 2009

The use of germanium (Ge) and the possibility of exposure to trace and ultratrace amounts of this element is increasing. Germanium is widely used in the industrial field as a semiconductor and also as a dietary supplement, an elixir to ‘promote health and cure disease’ (e.g. cancer and AIDS). More recently, germanium nanoparticles, ranging in size from 60 to 80 nm, have been developed as a potential spleen imaging agent. Like other metal‐based nanoparticles used in nanomedicine, Ge nanoparticles may release trace and ultratrace amounts of Ge ions when injected. The metabolic fate and toxicity of these ions still needs to be evaluated. In this study the metabolic fate of a cationic tetravalent Ge species was studied in vivo by injecting rats i.p. with ultratrace amounts of Ge (80 ng kg−1) as [68Ge]GeCl4. The cytotoxicity and carcinogenic potential was assessed in vitro using immortalised human skin keratinocytes and mouse fibroblasts (HaCaT and Balb/c 3T3 cell lines, respectively). At 24 h post‐exposure Ge was poorly retained in rat tissues (kidney, liver, intestine, femur, spleen and the heart were the organs with the highest Ge concentration). In the blood, Ge was rapidly cleared, being almost equally distributed between plasma and red blood cells. The excretion was mainly via the urine. The hepatic and renal intracellular distribution showed the highest recovery of Ge in the cytosol and the nuclear fractions. Chromatographic separation and ultrafiltration experiments on kidney and liver cytosols showed that the bulk of Ge was associated with low molecular weight components, representing a ‘mobile pool’ of the element in the body. However, a significant part of the element was able to interact with biological macromolecules which could be responsible for the presence of Ge in the liver and kidney after 7 days. The in vitro experiments confirmed the low degree of cytotoxicity of GeCl4 both in HaCaT and Balb/3T3. The latter model was more sensitive to the toxic effects induced by Ge as shown by a colony forming efficiency (CFE) greater than 70% at 700 µm of exposure. At the highest exposure concentration tested (700 µm) GeCl4 failed to induce morphological neoplastic transformation of the cells, suggesting for the first time that a cationic form of Ge ions has no carcinogenic potential. This supports the results of the only study reported in mice, treated orally long‐term to an anionic species of Ge such as sodium germanate (Kanisawa and Schroeder, 1967). Copyright © 2009 John Wiley & Sons, Ltd.
PPARα and PPARγ are co‐expressed, functional and show positive interactions in the rat urinary bladder urothelium
Authors: Egerod Frederikke Lihme , Brünner Nils , Svendsen Jette E. , Oleksiewicz Martin B.
Published: September 2009

Some dual‐acting PPARα + γ agonists cause cancer in the rat urinary bladder, in some cases overrepresented in males, by a mechanism suggested to involve chronic stimulation of PPARα and PPARγ, i.e. exaggerated pharmacology. By western blotting, we found that the rat urinary bladder urothelium expressed PPARα at higher levels than the liver and heart, and comparable to kidney. Urothelial expression of PPARγ was above that of fat, heart, skeletal muscle and kidney. Male rats exhibited a higher PPARα/PPARγ expression balance in the bladder urothelium than did female rats. Rats were treated by gastric gavage with rosiglitazone (PPARγ agonist), fenofibrate (PPARα agonist) or a combination of rosiglitazone and fenofibrate for 7 days. In the urothelium, the transcription factor Egr‐1 was induced to significantly higher levels in rats co‐administered rosiglitazone and fenofibrate than in rats administered either rosiglitazone or fenofibrate alone. Egr‐1 was also induced in the heart and liver of rats treated with fenofibrate, but a positive interaction between rosiglitazone and fenofibrate with regards to Egr‐1 induction was only seen in the urothelium. Thus, in the rat urinary bladder urothelium, PPARα and PPARγ were expressed at high levels, were functional and exhibited positive interactions. Interestingly, fenofibrate induced the peroxisome membrane protein PMP70 not only in liver, but also in the bladder urothelium, opening the possibility that oxidative stress may contribute to rat urothelial carcinogenesis by dual‐acting PPARα + γ agonists. Copyright © 2009 John Wiley & Sons, Ltd.
Developmental plasticity, modularity, and heterochrony during the phylotypic stage of the zebra fish, Danio rerio
Authors: Schmidt Kai , Starck J. Matthias
Published: September 2009

We studied early embryonic development of zebra fish and tested if changes in the external raising conditions could elicit phenotypic changes during the phylotypic stage which, classically, is considered as a conserved embryonic stage. In particular, we tested for internal constraints, plasticity, and heterochrony during the early embryonic development. Our tested hypotheses predict (i) no change associated with developmental stability/internal constraints, (ii) change of the rate of development associated with developmental flexibility, and (iii) heterochronic disruption of developmental pattern associated with a modular organization of the embryo. We measured 14 traits of embryos raised in different conditions (temperature, salinity, oxygen concentration). The results of our study show that zebra fish embryos respond flexibly to changes in external parameters even during the conserved “phylotypic stage.” It also showed that internal constraints canalize early development when exposed to moderate external challenges. Hypoxic conditions, however, elicited a heterochronic delay of the onset of the development of the Anlagen of the eye and the otic vesicle from the remaining embryo. Therefore, we concluded that the eye and the otic vesicle are modules that may develop, to a certain degree, independently of the rest of the embryo. Because these modules become recognizable only under specific raising conditions, we suggest that the modularization acts as buffering mechanism against extreme developmental deviations. Our results provide support to the idea that modularity is present during the phylotypic stage, but it is not effective under normal conditions. J. Exp. Zool. (Mol. Dev. Ecol.) 314B:166–178, 2010. © 2009 Wiley‐Liss, Inc.
Evaluation of the muscle gene transfer activity of a series of amphiphilic triblock copolymers
Authors: Alimi‐Guez Debborah , Leborgne Christian , Pembouong Gaelle , Van Wittenberghe Laetitia , Mignet Nathalie , Scherman Daniel , Kichler Antoine
Published: September 2009

Background

Amphiphilic triblock copolymers such as the polyethylene oxide‐polypropylene oxide‐polyethylene oxide L64 (PEO13‐PPO30‐PEO13) significantly increase transgene expression after injection of DNA/polymer mixtures into skeletal muscles. To better understand the way such copolymers act, we studied the behaviour of different poloxamers, including L64, both in vitro and in vivo.

Methods

The in vitro and in vivo transfection activity of five copolymers that differ either by their molecular weight or by their hydrophilic/hydrophobic balance was evaluated. Furthermore, we also studied the membrane permeabilizing properties of the poloxamers.

Results

The results obtained indicate that, after intramuscular administration of DNA/poloxamer formulations, all five compounds were able to significantly increase the expression levels of luciferase compared to an injection of naked DNA. Using a LacZ expression cassette, up to 30% of the muscle fibers expressed the reporter gene. Furthermore, we show that the effect can be obtained using different promoters. Finally, we document that, to some extent, all five poloxamers possess membrane permeabilizing properties.

Conclusions

Taken together, the results obtained in the present study show that there is a large flexibility in terms of molecular weight and EO/PO ratio for obtaining increased levels of transgene expression in vivo. Copyright © 2009 John Wiley & Sons, Ltd.
Pleural effusion associated with pegylated interferon alpha and ribavirin treatment for chronic hepatitis C
Authors: Arora Amit , Vargas Leonardo , Kuzniar Tomasz J.
Published: September 2009

Lung toxicity related to interferon (IFN) alpha typically takes a form of interstitial pneumonitis, granulomatous inflammation, or organizing pneumonia. We report a case of a 52‐year‐old woman, who developed pneumonitis with exudative, lymphocytic‐predominant pleural effusion following treatment with pegylated IFN alpha and ribavirin for hepatitis C. Her symptoms and lung findings resolved over 3 months of observation without corticosteroid therapy. Journal of Hospital Medicine 2009;4:E45–E46. © 2009 Society of Hospital Medicine.
Use of simulation‐based mastery learning to improve the quality of central venous catheter placement in a medical intensive care unit
Authors: Barsuk Jeffrey H. , McGaghie William C. , Cohen Elaine R. , Balachandran Jayshankar S. , Wayne Diane B.
Published: September 2009

BACKGROUND:

Central venous catheter (CVC) insertions are performed frequently by internal medicine residents. Complications, including arterial puncture and pneumothorax, decrease when operators use fewer needle passes to insert the CVC. In this study, we evaluated the effect of simulation‐based mastery learning on CVC insertion skill.

DESIGN:

This was a cohort study of internal jugular (IJ) and subclavian (SC) CVC insertions by 41 internal medicine residents rotating through the medical intensive care unit (MICU) over a five‐month period. Thirteen traditionally‐trained residents were surveyed about the number of needle passes, complications, and procedural self‐confidence on CVCs inserted in the MICU. Concurrently, 28 residents completed simulation‐based training in IJ and SC CVC insertions. Simulator‐trained residents were expected to perform CVC insertions to mastery standards on a central line simulator. Simulator‐trained residents then rotated through the MICU and were surveyed regarding CVC placement. The impact of simulation training was assessed by comparing group survey results.

RESULTS:

No resident met the minimum passing score (MPS) (79.1%) for CVC insertion at baseline: mean (M) (IJ) = 48.4%, standard deviation (SD) = 23.1, M(SC) = 45.2%, SD = 26.3. All residents met or exceeded the MPS at testing after simulation training: M(IJ) = 94.8%, SD = 10.0, M(SC) = 91.1%, SD = 17.8 (p < 0.001). In the MICU, simulator‐trained residents required fewer needle passes to insert a CVC than traditionally‐trained residents: M = 1.79, SD = 1.0 versus M = 2.78, SD = 1.77 (p = 0.04). Simulator‐trained residents displayed more self‐confidence about their procedural skills: (M = 81, SD = 11 versus M = 68, SD = 20, p = 0.02).

CONCLUSIONS:

Simulation‐based mastery learning increased residents' skills in simulated CVC insertion, decreased the number of needle passes when performing actual procedures, and increased resident self‐confidence. Journal of Hospital Medicine 2009;4:397–403. © 2009 Society of Hospital Medicine.
Benign pneumatosis intestinalis in a child with cavopulmonary shunt and immune thrombocytopenic purpura
Authors: Burns Lindsay , Maul Erich C.
Published: September 2009

We present the case of a nine‐year‐old boy with hypoplastic left heart syndrome and immune thrombocytopenic purpura who subsequently developed pneumatosis intestinails with a benign clinical examination. While benign pneumatosis intestinails is a well‐known clinical entity, the alarming radiographic findings set off a cascade of clinical angst among many providers. This case reminds physicians to correlate the ancillary study results with the patient's clinical presentation and stability. Journal of Hospital Medicine 2009;4:E41–E42. © 2009 Society of Hospital Medicine.
Improving insulin ordering safely: The development of an inpatient glycemic control program
Authors: Thompson Rachel , Schreuder Astrid B. , Wisse Brent , Jarman Kenny , Givan Kathleen , Suhr Louise , Corl Dawn , Pierce Becky , Knopp Robert , Goss J. Richard
Published: September 2009

This report describes a Glycemic Control Program instituted at an academic regional level‐one trauma center. Key interventions included: 1) development of a subcutaneous insulin physician order set, 2) use of a real‐time data report to identify patients with out‐of‐range glucoses, and 3) implementation of a clinical intervention team. Over four years 18,087 patients admitted to non‐critical care wards met our criteria as dysglycemic patients. In this population, glycemic control interventions were associated with increased basal and decreased sliding scale insulin ordering. No decrease was observed in the percent of patients experiencing hperglycemia. Hypoglycemia did decline after the interventions (4.3% to 3.6%; p = 0.003). Distinguishing characteristics of this Glycemic Control Program include the use of real‐time data to identify patients with out‐of‐range glucoses and the employment of a single clinician to cover all non‐critical care floors. Journal of Hospital Medicine 2009;4:E30–E35. © 2009 Society of Hospital Medicine.