bluuebunny/crossref_metadata_2025 huggingface dataset:
Adsorption of human immunoglobulin to implantable alginate‐poly‐L‐lysine microcapsules: Effect of microcapsule composition
Authors: Tam Susan K. , de Haan Bart J. , Faas Marijke M. , Hallé Jean‐Pierre , Yahia L'Hocine , de Vos Paul
Published: April 2008

Alginate‐poly‐L‐lysine‐alginate (APA) microcapsules continue to be the most widely studied device for the immuno‐protection of transplanted therapeutic cells. Producing APA microcapsules having a reproducible and high level of biocompatibility requires an understanding of the mechanisms of the immune response towards the implants. Here, we investigate the adsorption of immunoglobulins (IgG, IgM, and IgA) onto the surface of APA microcapsules in vitro after their exposure to human serum and peritoneal fluid. Immunoglobulins (Ig) are considered to be opsonizing proteins, thus they tend to mediate inflammation when adsorbed to foreign surfaces. Ig adsorption was monitored using direct immunofluorescence. The amount of Ig adsorbed to the microcapsule surface was not significantly influenced by the guluronic acid content nor the purity level of the alginate, although microcapsules of intermediate‐G purified alginate corresponded with the lowest adsorption levels. Ig adsorption was negligible when the poly‐L‐lysine membrane was omitted, suggesting that positive charges at the microcapsule surface are responsible for binding Ig. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Ni(II) ions dysregulate cytokine secretion from human monocytes
Authors: Lewis Jill B. , Messer Regina L. W. , Pitts Leslie , Hsu Stephen D. , Hansen Jason M. , Wataha John C.
Published: April 2008

Nickel‐containing alloys are used in dentistry because of their low cost, but poor corrosion behavior increases their risk of causing adverse biological responses. Intraorally, nickel‐containing alloys accumulate bacterial plaque that triggers periodontal inflammation via toxins such as lipopolysaccharide (LPS). Recent evidence suggests that in monocytes, Ni(II) amplifies LPS‐induced secretion of several cytokines that mediate periodontal destruction. Thus, we investigated the effects of Ni(II), with or without LPS, on the secretion of a broader array of cytokines from monocytes. We then measured monocytic expression of two proteins, Nrf2 and thioredoxin‐1 (Trx1), that influence the regulation of cytokine secretion. Cytokine arrays were used to measure the effects of 0–50 μM Ni(II) on cytokine secretion from human THP1 monocytes, with or without LPS activation. Immunoblots were used to estimate Nrf2 and Trx1 levels. Our results indicate that both Ni(II) alone and Ni(II) with LPS have broad‐based effects on cytokine secretion. Ni(II) increased Nrf2 levels by threefold, and LPS amplified the effects of Ni(II) by 10‐fold. Trx1 levels did not change under any condition tested. Our results suggest that Ni(II)‐induced changes in cytokine secretion by monocytes are diverse and may be influenced by Nrf2 but are not likely influenced by changes in whole‐cell Trx1 levels. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Bacterial transmission from lens storage cases to contact lenses—Effects of lens care solutions and silver impregnation of cases
Authors: Vermeltfoort Pit B. J. , Hooymans Johanna M. M. , Busscher Henk J. , van der Mei Henny C.
Published: April 2008

The killing efficacies of multipurpose lens care solutions on planktonic and biofilm bacteria grown in polypropylene contact lens storage cases with and without silver impregnation and effects on bacterial transmission from storage cases to silicone hydrogel contact lenses were investigated. For transmission studies, biofilms of Staphylococcus aureus 835 or Pseudomonas aeruginosa no. 3 were grown on lens storage cases and incubated with a contact lens in different multipurpose lens care solutions (Opti‐Free®Express®, ReNu® MultiPlus®, and SoloCare Aqua™) or 0.9% NaCl. In addition, planktonic bacteria were directly suspended in multipurpose solutions and their killing efficacies were determined. The numbers of transmitted live and dead bacteria on the lenses were measured using a combination of plate counting and fluorescence microscopy. The highest killing efficacies were shown by Opti‐Free® Express® for planktonic as well as for biofilm bacteria. Silver impregnation of lens cases in combination with the prescribed solution increased the killing efficacy for P. aeruginosa in biofilms, whereas effects for S. aureus were minor. Lowest numbers of live and dead bacteria were transmitted to a lens in Opti‐Free® Express® multipurpose solution, with no significant differences between lens types and no effects of silver impregnation. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Self‐setting properties and in vitro bioactivity of Ca2SiO4/CaSO4·1/2H2O composite bone cement
Authors: Huan Zhiguang , Chang Jiang , Huang Xiang‐Hui
Published: April 2008

In this study, a biphasic injectable bone substitute based on β‐dicalcium silicate (Ca2SiO4) and plaster of Paris (CaSO4·1/2H2O) is presented, and its behavior as cement was studied and compared to that of pure Ca2SiO4 paste. The results demonstrated that the setting time of the workable Ca2SiO4/CaSO4·1/2H2O pastes was only 15 min, which was significantly reduced as compared to that of the Ca2SiO4 paste (100 min), and the composite showed higher short‐ and long‐term mechanical strength (3.25 and 37.2 MPa, respectively) than those of the Ca2SiO4 paste (0.2 and 24.6 MPa). Similar to the pure Ca2SiO4 paste, the composite paste could induce apatite formation in simulated body fluid within a short period and degrade in Ringer's solution. Moreover, the degradation rate could be adjusted by modifying the content of the plaster within the composite cement. These results suggested that the addition of the plaster significantly improved the self‐setting properties of the Ca2SiO4 paste, and the bioactive composite cement could be a prospective candidate for further investigation as self‐setting tissue‐repairing substitute. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Effects of electron attachment on C5′O5′ and C1′N1 bond cleavages of pyrimidine nucleotides: A theoretical study
Authors: Xie Hujun , Wu Ruibo , Xia Fei , Cao Zexing
Published: April 2008

Sugar‐base C1′N1 and phosphate‐sugar C5′O5′ bond breakings of 2′‐deoxycytidine‐5′‐monophosphates (dCMP) and 2′‐deoxythymidine‐5′‐ monophosphates (dTMP) and their radical anions have been explored theoretically at the B3LYP/DZP++ level of theory. Calculations show that the low‐energy electrons attachment to the pyrimidine nucleotides results in remarkable structural and chemical bonding changes. Predicted Gibbs free energies of reaction ΔG for the C5′O5′ bond dissociation process of the radical anions are −14.6 and −11.5 kcal mol−1, respectively, and such dissociation processes may be intrinsically spontaneous in the gas phase. Furthermore, the C5′O5′ bond cleavage processes of the anionic dCMP and dTMP were predicted to have activation energies of 6.9 and 8.0 kcal mol−1 in the gas phase, respectively, much lower than the barriers for the C1′N1 bond breaking process, showing that the CO bond dissociation in DNA single strand breaks is a dominant process as observed experimentally. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008
Electron localizability for hexagonal element structures
Authors: Baranov A. I. , Kohout M.
Published: April 2008

For 21 elements crystallizing in hexagonal structure density functional calculations were performed. The topology of the electron localizability indicator (ELI) allows classifying the elements as appertaining to one of six patterns. The bifurcation diagrams as well as the electron populations in ELI basins for each pattern are discussed. © 2008 Wiley Periodicals, Inc. J Comput Chem 2008
Sensitivity study of the urban heat island intensity to urban characteristics
Authors: Hamdi R. , Schayes G.
Published: April 2008

A detailed urban surface exchange parameterization, implemented in a meso‐scale atmospheric model, has been used to study the urban heat island (UHI) intensity during a summer period in the city of Basel, Switzerland. In this urban parameterization, the city is represented as a combination of three urban classes (road, roof and wall), characterized by the size of the street canyon and the building and is thus able to take into account the momentum sink over the entire height of the building, as well as the shadowing and the radiation trapping effects. A control experiment including all the urban parameters describing the city centre of Basel produced a canyon air temperature that compared well with observations. A series of experiments was then conducted in which successively each of the urban parameters characterizing the city centre was changed providing the basis for an assessment of its effect on UHI mitigation. Copyright © 2007 Royal Meteorological Society
Unsaturated fatty acids liberated from VLDL cause apoptosis in endothelial cells
Authors: Reinbold Michael , Hufnagel Birgit , Kewitz Tobias , Klumpp Susanne , Krieglstein Josef
Published: April 2008

Certain unsaturated fatty acids (UFAs), cleaved from lipoproteins, are known to activate the serine/threonine protein phosphatase type 2C (PP2C) α‐ and β‐isoforms. To investigate the role of UFAs in apoptosis of endothelial cells, we cocultured human umbilical vein endothelial cells (HUVECs) with THP‐1 monocytes. Phorbol‐12‐myristic‐13‐acetate (PMA)‐treated THP‐1 monocytes differentiated into macrophages and synthesized lipoprotein lipase (LPL), the major enzyme for hydrolysis of triglycerides. We demonstrated that LPL from THP‐1 macrophages released UFAs from VLDL, which were capable of inducing apoptosis in HUVECs. Physiological concentrations of VLDL did not cause apoptosis in HUVECs, whereas the combination of VLDL with LPL‐rich cell medium of THP‐1 macrophages did. THP‐1 macrophages and HUVECs in cocultivation did not interfere with each other. However, addition of VLDL to this coculture caused apoptosis in HUVECs. Furthermore, inhibition of LPL by adding orlistat to the culture medium and down‐regulation of LPL by small interfering RNA (siRNA) reduced the extent of apoptosis of HUVECs. In conclusion, our results show that the amounts of UFAs liberated from lipoproteins are high enough to induce apoptosis in endothelial cells. This underlines the proatherogenic role of UFAs in hyperlipoproteinemias.
A novel differential bandpass filter based on double‐sided parallel‐strip line dual‐mode resonator
Authors: Shi Jin , Chen Jian‐Xin , Xue Quan
Published: April 2008

A differential bandpass filter based on double‐sided parallel‐strip line (DSPSL) dual‐mode resonator is proposed in this article. This differential bandpass filter makes use of the inherent differential feature of DSPSL to construct feeding ports and resonating unit. This filter has the advantages of low‐profile structure, low‐insertion loss for differential‐mode signal, and high suppression for common‐mode signal. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1733–1735, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23493
A wide stopband and low loss bandpass filter using multiorder harmonic suppressedI/Olines
Authors: Ramírez Vargas Steve , Weng Min‐Hang , Liauh Chihng‐Tsung , Wu Hung‐Wei , Yang Ru‐Yuan
Published: April 2008

In this article, a new wide stopband and low loss patch bandpass filter (BPF) using multiorder harmonic suppression is proposed. Two kinds of suppressed structures located under the I/O lines have been utilized to generate a wide harmonic suppression without affecting the performances at central frequency (f0). Design procedure of the proposed filter is described in detail in this article. The BPF designed at 2.4 GHz (f0) has the suppression up to −60, −43, and −31 dB measured at 2f0, 3f0, and 4f0, respectively. Additionally, a size reduction of the proposed filter is up to 31.2%, compared with the conventional structure. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1893–1897, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23515
One‐step hot embossing of optical rib waveguides in chalcogenide glasses
Authors: Pan W. J. , Rowe H. , Zhang D. , Zhang Y. , Loni A. , Furniss D. , Sewell P. , Benson T. M. , Seddon A. B.
Published: April 2008

A new technique is presented for fabricating optical rib waveguides in chalcogenide glasses. As40Se60/Ge17As18Se65 (at. %) rib waveguides were fabricated in a one‐step process by hot pressing two As40Se60 fibers sandwiched between a silicon mold and a planar Ge17As18Se65 glass substrate, resulting in a series of replicated thin‐film rib structures on glass. Optical characterization at λ = 1.55 μm reveals single‐mode waveguide propagation, in agreement with numerical modeling. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1961–1963, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23534
Simulating temporal evolution of PMD‐related variables in optical fibers and emulators
Authors: Ferreira J. , Vilela de Faria G. , von der Weid J. P.
Published: April 2008

A simulation tool for the calculation of the statistics and correlations of PMD‐related variables is presented. Calculations are performed in time domain, allowing the simulation of the temporal evolution of differential group delay (DGD); principal states of polarization (PSP); output polarization state (SOP) and received signal level, among others. Results are in good agreement with predictions from spectral calculations and experimental results. Simulations are used to compare predictions of the hinge model and to evaluate PMD outage times in optical transmissions. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1950–1954, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23548
Delivery‐date and capacity management in a decentralized internal market
Authors: Erkoc Murat , Wu S. David , Gurnani Haresh
Published: April 2008

We study competitive due‐date and capacity management between the marketing and engineering divisions within an engineer‐to‐order (ETO) firm. Marketing interacts directly with the customers and quotes due‐dates for their orders. Engineering is primarily concerned with the efficient utilization of resources and is willing to increase capacity if the cost is compensated. The two divisions share the responsibility for timely delivery of the jobs. We model the interaction between marketing and engineering as a Nash game and investigate the effect of internal competition on the equilibrium decisions. We observe that the internal competition not only degrades the firm's overall profitability but also the serviceability. Finally, we extend our analysis to multiple‐job settings that consider both flexible and inflexible capacity. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008
Life on horseback: palaeopathology of two Scythian skeletons from Alexandropol, Ukraine
Authors: Wentz R. K. , de Grummond N. T.
Published: April 2008

In 2006, two skeletons were analysed that were previously excavated from the periphery of a Scythian burial mound, near the village of Alexandropol in southern Ukraine. Dated to ca. 325 BC, both remains are male. The first is that of a youth in his late teens who exhibits indications of biological stress and degenerative changes to the spine in the form of a Schmorl's node. The second is a middle‐aged individual with extensive healed lesions due to trauma to the right humerus and clavicle with associated bony changes of the elbow and spine. Stable isotope analyses indicate a diet based on C3 plants. Their skeletons suggest a rigorous life on horseback. Both may have served as sacrificial victims. Historical records document the strangulation of attendants and their placement around the periphery of royal burial mounds. Grave goods suggest that both were warriors, although the youth lacks the traumatic injuries exhibited by the older male. The individuals from Alexandropol may have served a Scythian king in life and in death. Copyright © 2008 John Wiley & Sons, Ltd.
Membrane‐associated phospholipase A1 beta (LIPI) Is an Ewing tumour‐associated cancer/testis antigen
Authors: Foell Juergen L. , Hesse Manuela , Volkmer Ines , Schmiedel Benjamin J. , Neumann Ingo , Staege Martin S.
Published: April 2008

Background

Cancer/testis antigens (CTA) represent a heterogeneous group of antigens expressed nearly exclusively in tumour cells and testis. Recently, we identified phospholipase A1 beta (a CTA also known as lipase member I, LIPI) as a gene with high expression in Ewing family tumours (EFT). In the present paper we analyzed expression of LIPI in a panel of normal tissues and tumour samples.

Procedure

The expression of CTA in EFT and normal tissues was analyzed by using DNA microarray datasets. Expression of LIPI in EFT, a panel of other tumour samples, and normal tissues was analyzed by using RT‐PCR and quantitative RT‐PCR.

Results

LIPI was expressed in EFT samples but not in other investigated tumour samples. Expression of LIPI in normal tissues was restricted to testis and thyroid. However, expression in these tissues was low compared with EFT. Interestingly testis as well as thyroid expressed all analyzed EFT‐associated transcripts, suggesting that these tissues harbour a small cell population with molecular features of EFT. The sensitivity of the LIPI RT‐PCR was similar to the sensitivity of the conventional EWSR1‐FLI1 RT‐PCR, suggesting that LIPI might be useful as additional diagnostic target structure.

Conclusions

The human cancer/testis antigen LIPI is highly expressed in Ewing family tumours and can be easily detected by RT‐PCR or quantitative RT‐PCR. LIPI might be an interesting target for the development of future diagnostic tools or treatment strategies. Pediatr Blood Cancer 2008;51:228–234. © 2008 Wiley‐Liss, Inc.
Properties of polyamide‐zirconia nanocomposites prepared from sol‐gel technique
Authors: Sarwar Muhammad Ilyas , Zulfiqar Sonia , Ahmad Zahoor
Published: April 2008

Transparent nanocomposites were prepared by producing zirconia network in glassy polyamide matrix using sol‐gel technique. Different amounts of tetrapropyl zirconate (TPZ) were added in polymer solution using anhydrous dimethylformamide as solvent. TPZ was hydrolyzed and condensed in situ in the matrix for the generation of inorganic networks using diethylamine. Thin and transparent films containing different proportions of zirconia were obtained by evaporating the solvent. Mechanical, dynamic mechanical thermal and morphological analyses of these films were carried out. An increase in tensile modulus was observed with the films containing zirconia contents up to 15 wt%, but the elongation at rupture was found to decrease sharply on further addition of zirconia. Toughness of the hybrid materials decreased with increased amount of zirconia. Dynamic mechanical thermal analysis (DMTA) performed on the samples indicates an increase in the glass transition temperature; 102°C with pure polyamide to 132°C with polyamide containing 15 wt% zirconia contents. The storage modulus was also found to increase with increase in zirconia proportion in the matrix. The decrease in the storage modulus of the hybrids with rise in temperature was observed to be much smaller as compared with that of pure polymer. Thermal decomposition temperatures of the hybrids were found in the range of 450–500°C. The weights of the residues left at 700°C were nearly proportional to the zirconia contents in the original hybrids. The morphological studies suggest a uniform dispersion of zirconia domains in the matrix. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Development of a transparent PMMA composite reinforced with nanofibers
Authors: Chen Lu‐Song , Huang Zheng‐Ming , Dong Guo‐Hua , He Chuang‐Long , Liu Ling , Hu Ying‐Ying , Li Yan
Published: April 2008

Core‐shell composite nanofibers with PA‐6 (Nylon‐6) as core and Poly (methyl methacrylate) (PMMA) as shell were fabricated by a coaxial electrospinning method, which were later made into nanofiber reinforced transparent composites through a hot press treatment. Morphological and structural characterizations for the composite nanofibers and the transparent composites were realized in terms of SEM, TEM, and FTIR techniques. The fiber reinforcement feature of the PA‐6 was demonstrated by the SEM photos of a composite sample fractured in liquid nitrogen. Through TGA and DSC tests, it was observed that thermal endurance and glass‐transition temperature of the nanofiber reinforced composites altered in variation with the contents of the reinforcing PA‐6. Experimental results indicated that the mechanical performance of the nanofiber reinforced transparent composites was obviously improved, and its transparency decreased a little with an increase in the PA‐6 content. As long as, however, a sacrifice of 10% in transparency was specified, an increment of more than 20% in the mechanical properties of the composites was achievable. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Electrical conduction in (polyvinyl alcohol/glycogen) blend films
Authors: Abd El‐kader F.H. , Gaafer S.A. , Mahmoud K.H. , Mohamed S.I. , Abd El‐kader M.F.H.
Published: April 2008

Cast thin films of polyvinyl alcohol/glycogen blends of different compositions have been prepared and subjected to the electrical measurements of both current–time and current–voltage characteristics as well as d.c. conductivity as a function of temperature. The conduction mechanisms operative in the films at different temperature and voltage ranges are estimated from the behavior of log I versus V1/2 plots. For individual polymers, the conduction mechanism appears to be essentially a Poole–Frenkel type. On blending, at lower temperature the charge conduction is through the Schottky emission while at higher temperature the charge conduction mechanism is Poole–Frenkel. In addition, the deviation of the plots at lower voltages indicates the existence of space charge contribution in conduction mechanism. The obtained results made it possible to determine several conduction parameters including activation energy, carrier mobility, and carrier concentration. POLYM. COMPOS., 2009. © 2008 Society of Plastics Engineers
Separation and purification of four chromones from radix saposhnikoviae by high‐speed counter‐current chromatography
Authors: Liu Renmin , Wu Sujuan , Sun Ailing
Published: April 2008

A preparative high‐speed counter‐current chromatography (HSCCC) method for the isolation and purification of 1″‐O‐glucosylcimifugin (1), 4′‐O‐β‐d‐glucosyl‐5‐O‐methylvisamminol (2), cimifugin (3) and 3′‐O‐glucosylhamaudol (4) from the Chinese medicinal herb radix saposhnikoviae has been successfully developed. A sample of 300 mg of crude extract was separated using ethyl acetate:n‐butanol:1% aqueous acetic acid (1:4:5, v/v) as the two‐phase solvent system and yielded 102.4 mg of 1 and 81.6 mg of 2. During this separation 3 and 4 remained in the stationary phase, which was collected, evaporated to dryness and separated with another two‐phase solvent system involving ethyl acetate:n‐butanol:1% aqueous acetic acid (5:0.5:5, v/v) to yield 31.4 mg of 3 and 12.7 mg of 4. The purities of compounds 1–4 were 98.4, 98.7, 99.3 and 98.2%, respectively, as determined by HPLC. The chemical structures of these components were established by 1H‐NMR and 13C‐NMR. Copyright © 2008 John Wiley & Sons, Ltd.
A comparison of measures of disproportionality for signal detection on adverse drug reaction spontaneous reporting database of Guangdong province in China
Authors: Li Chanjuan , Xia Jielai , Deng Jianxiong , Jiang Jing
Published: April 2008

Purpose

To examine the concordance of various measures to Bayesian Confidence Propagation Neural Network (BCPNN) measure used by the WHO Collaborating Centre for International Drug Monitoring based on the database of Guangdong province in China.

Methods

The Reporting Odds Ratio (ROR) − 1.96 standard errors (SE), Proportional Reporting Ratio (PRR) − 21.96 SE, combination χ
2‐PRR measure used by the Medicines and Healthcare Products Regulatory Agency (MHRA) were compared with the IC − 2 standard deviations (SDs) with the tested database collected from 1 January 2002 to 30 June 2007 in Guangdong. Additionally, the concordance of the various measures, in respect to the number of reports per combination, was examined.

Results

Sensitivity, specificity, positive predictive value and negative predictive value were high in respect to the BCPNN measure when a combination of point and interval estimate was used based on four types of signal detection for the ROR and PRR measures, and the four evaluation indexes increased when A (the number of reports per combination) increased. However the MHRA measure had decreasing sensitivity and increasing specificity with A increasing.

Conclusions

The ROR, PRR and BCPNN measures used are broadly comparable when three or more cases per combination have been collected. The MHRA measure is comparable to the BCPNN when seven or less case per combination have been collected for ‘drug–ADR’, ‘drug category–ADR’, ‘drug–ADR category’ combinations based on the Guangdong database, and the MHRA is unsuitable for detecting signals from ‘drug category–ADR category’ combinations based on the Guangdong database because of its low sensitivity. Copyright © 2008 John Wiley & Sons, Ltd.
Role of structural modification on the electrical properties of poly(ethylene terephthalate) irradiated with 90‐MeV carbon ion beam
Authors: Srivastava A. , Singh V. , Kulriya P. , Vyas S. , Sen P. , Bandopadhay S.K. , Singh T.V.
Published: April 2008

Thin films of poly(ethylene terephthalate) (PET) having a thickness of 100 μm were exposed to different ion fluence of swift heavy ions of carbon in the range of 5 × 1011 – 5 × 1013 ions/cm2. The effect of ion beam on structural and electrical modification has been studied by UV/vis, FTIR, X‐ray diffraction (XRD), Differential Scanning Calorimetery (DSC), and AC electrical measurement techniques. On irradiation, a shift in absorption wavelength toward the red end of spectrum with increase of ion fluence was observed. The intensity of crystalline IR bands and main diffraction peak in XRD pattern were found to decrease with increase in ion fluence. It indicates the loss of crystallinity induced by ion‐beam irradiation. The crystallite size was found to increase on irradiation. The melting temperature (Tm) of PET films increased at a low ion dose (5.0 × 1012 ions/cm2), while it decreased at higher ion fluence (50.0 × 1012 ions/cm2). The dielectric constant (ε′) of PET films was increased with increase of ion fluence. The modifications brought about in the dielectric constant are correlated with chemical and molecular structural changes occurring on irradiation. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers.
Lithium difluoro(oxalate)borate‐based novel nanocomposite polymer electrolytes for lithium ion batteries
Authors: Aravindan Vanchiappan , Vickraman Palanisamy , Krishnaraj Kaliappa
Published: April 2008

BACKROUND: HF formation and poor thermal stability found in commercial lithium ion batteries comprising LiPF6 (and other salts) have hampered the replacement of LiPF6. Therefore, a new kind of electrolyte salt is necessary to replace the one commercially available.

RESULTS: A novel lithium difluoro(oxalate)borate (LiDFOB)‐based nanocomposite polymer electrolyte has been prepared in a matrix of poly[(vinylidene fluoride)‐co‐(hexafluoropropylene)] (PVdF‐HFP). The electrolyte contains ethylene carbonate and diethyl carbonate as plasticizers and nanoparticulate Sb2O3 as a filler. Membranes obtained by a solution casting technique were characterized by AC impedance, thermogravimetry and tensile strength measurements and morphological studies. Membranes with 5 wt% Sb2O3 exhibit a room‐temperature conductivity of 0.298 mS cm−1, and are thermally stable up to ca 130 °C. Furthermore, the nanocomposite membranes show a 125% increase in mechanical stability as compared to filler‐free membranes. The structural change from α to β phases was confirmed by Raman studies.

CONCLUSION: One of the important advantages of using LiDFOB lies in its bulkier DFOB anion, which also acts as solid plasticizer, thus improving the basic requirements of the electrolyte, such as mechanical and thermal stabilities, as well ionic conductivity and with a lower filler content. The overcharge tolerance of LiDFOB salt at higher temperature is also to be noted, because of the oxalate moieties. Preliminary investigations confirmed the possibility of using Sb2O3 nanoparticle‐filled membranes in industry in the near future. Copyright © 2008 Society of Chemical Industry
Polymerization of oligo(ethylene glycol) (meth)acrylates: Toward new generations of smart biocompatible materials
Authors: Lutz Jean‐François
Published: April 2008

Monomers composed of a (meth)acrylate moiety connected to a short poly(ethylene)glycol (PEG) chain are versatile building‐blocks for the preparation of “smart” biorelevant materials. Many of these monomers are commercial and can be easily polymerized by either anionic, free‐radical, or controlled radical polymerization. The latter approach allows synthesis of well‐defined PEG‐based macromolecular architectures such as amphiphilic block copolymers, dense polymer brushes, or biohybrids. Furthermore, the resulting polymers exhibit fascinating solution properties in aqueous medium. Depending on the molecular structure of their monomer units, non linear PEG analogues can be either insoluble in water, readily soluble up to 100 °C, or thermoresponsive. Thus, these polymers can be used for building a wide variety of modern materials such as biosensors, artificial tissues, smart gels for chromatography, and drug carriers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3459–3470, 2008
Comparison between the dissolution of whey protein gels and of synthetic polymers
Authors: Mercadé‐Prieto Ruben , Paterson William R. , Wilson D. Ian
Published: April 2008

The dissolution behavior of heat‐induced whey protein gels in alkali is compared with the literature on the dissolution of (1) uncrosslinked synthetic polymers with chemical reaction, (2) uncrosslinked polymers in a good solvent, and (3) crosslinked hydrogels. Diffusion of hydroxide and acid–base reactions, which are key processes in the dissolution of phenolic resins in alkali (Case 1), are found not to be very important with protein gels. The strong dependency of the dissolution rate on the free volume observed in protein gels is described by a large scaling factor, as predicted for Case 2 theory, indicating that the disentanglement of long chains before they are released is important. The cleavage of intermolecular crosslinks, which is important in Case 3, is also identified as a key dissolution step, where the complexity of protein chemistry comes into play. Synthetic polymer mechanisms are therefore able to elucidate several aspects of protein gel dissolution, but are not yet sufficient to explain all aspects of the process. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 1007–1021, 2008
New Plasma Techniques for Polymer Surface Modification with Monotype Functional Groups
Authors: Friedrich Jörg F. , Mix Renate , Schulze Rolf‐Dieter , Meyer‐Plath Asmus , Joshi Ranjit , Wettmarshausen Sascha
Published: April 2008

The production of chemically‐defined plasma polymers and the introduction of monotype functional groups onto polymer surfaces are described. One method is to lower the energetic level of low‐pressure plasmas. Pressure‐ and plasma‐pulsed plasmas were successfully tested for the production of chemically‐defined plasma polymers by increasing the monomer supply during the plasma‐off period. Well‐defined ultra‐thin polymer films with regular structure were deposited from atmospheric plasmas by electrospray techniques. Post‐plasma wet‐chemical processing was also applied, as were gas/liquid‐based aerosols and underwater plasmas.

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Spontaneous resolution of diffuse persistent pulmonary interstitial emphysema
Authors: Jassal Mandeep S. , Benson Jane E. , Mogayzel Peter J.
Published: April 2008

Persistent pulmonary interstitial emphysema (PPIE) is a rare condition that occurs in both preterm and term infants. It is thought to arise from a disruption of the basement membrane of the alveolar wall allowing air entry into the interstitial space. The characteristic CT scan appearance of PPIE can be used to differentiate it from other congenital cystic lesions that may present similarly. Although conservative management is accepted as the initial form of management in most cases, a review of the published literature found that a significant proportion of localized PPIE cases eventually require surgical resection. This case illustrates that extensive bilateral PPIE associated with a persistent pneumomediastinum can resolve spontaneously thus demonstrating that conservative management without surgical intervention may be appropriate for some children. Pediatr Pulmonol. 2008; 43:615–619. © 2008 Wiley‐Liss, Inc.
Acute respiratory symptoms and general illness during the first year of life: A population‐based birth cohort study
Authors: von Linstow Marie‐Louise , Holst Klaus Kähler , Larsen Karina , Koch Anders , Andersen Per Kragh , Høgh Birthe
Published: April 2008

Respiratory symptoms are common in infancy. Most illnesses occurring among children are dealt with by parents and do not require medical attention. Nevertheless, few studies have prospectively and on a community‐basis assessed the amount of respiratory symptoms and general illness in normal infants. In this population‐based birth cohort study, 228 healthy infants from Copenhagen, Denmark were followed from birth to 1 year of age during 2004–2006. Symptoms were registered using daily diaries and monthly home visits. Interviews were performed at inclusion and every second month. Risk factor analysis was carried out by multiple logistic regression analysis. On average, children had general symptoms for 3.5 months during their first year of life, nasal discharge being most frequent followed by cough. Frequency of all symptoms increased steeply after 6 months of age. Each child had on average 6.3 episodes (median: 5.1, inter‐quartile range (IQR): 3.3–7.8) of acute respiratory tract illness (ARTI) (nasal discharge and ≥1 of the following symptoms: cough, fever, wheezing, tachypnea, malaise, or lost appetite) and 5.6 episodes (median: 4.3, IQR: 2.1–7.3) of simple rhinitis per 365 days at risk. Determinants for respiratory symptoms were increasing age, winter season, household size, size of residence, day‐care attendance, and having siblings aged 1–3 years attending a day nursery. In conclusion, the present study provides detailed data on the occurrence of disease symptoms during the first year of life in a general population cohort and emphasizes the impact of increasing age, seasonality, and living conditions on the occurrence of ARTI. Pediatr Pulmonol. 2008; 43:584–593. © 2008 Wiley‐Liss, Inc.
Isoform‐specific variation in the intrinsic disorder of troponin I
Authors: Hoffman Ryan M.B. , Sykes Brian D.
Published: April 2008

Various intrinsic disorder (ID) prediction algorithms were applied to the three tissue isoforms of troponin I (TnI). The results were interpreted in terms of the known structure and dynamics of troponin. In line with previous results, all isoforms of TnI were predicted to have large stretches of ID. The predictions show that the C‐termini of all isoforms are extensively disordered as is the N‐terminal extension of the cardiac isoform. Cardiac TnI likely belongs to the group of intrinsically disordered signalling hub proteins. For a given portion of the protein sequence, most ID prediction approaches indicate isoform‐dependent variations in the probability of disorder. Comparison of machine learning and physically based approaches suggests the ID variations are only partially attributable to local variations in the ratio of charged to hydrophobic residues. The VSL2B algorithm predicts the largest variations in ID across the isoforms, with the cardiac isoform having the highest probability of structured regions, and the fast‐skeletal isoform having no intrinsic structure. The region corresponding to residues 57–95 of the fast‐skeletal isoform, known to form a coiled coil substructure with troponin T, was highly variable between isoforms. The isoform‐specific ID variations may have mechanistic significance, modulating the extent to which conformational fluctuations in tropomyosin are communicated to the troponin complex. We discuss structural mechanisms for this communication. Overall, the results motivate the development of predictors designed to address relative levels of disorder between highly similar proteins. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Structural determinants of ligand migration in Mycobacterium tuberculosis truncated hemoglobin O
Authors: Boechi Leonardo , Martí Marcelo A. , Milani Mario , Bolognesi Martino , Luque F. Javier , Estrin Darío A.
Published: April 2008

Mycobacterium tuberculosis is the causative agent of human tuberculosis, one of the most prevalent infectious diseases in the world. Its genome hosts the glbN and glbO genes coding for two proteins, truncated hemoglobin N (trHbN) and truncated hemoglobin O (trHbO), that belong to different groups (I and II, respectively) of the recently discovered trHb family of hemeproteins. The different expression pattern and kinetics rates constants for ligand association and NO oxidation rate suggest different functions for these proteins. Previous experimental and theoretical studies showed that, in trHbs, ligand migration along the internal tunnel cavity system is a key issue in determining the ligand‐binding characteristics. The X‐ray structure of trHbO has been solved and shows several internal cavities and secondary‐docking sites. In this work, we present an extensive investigation of the tunnel/cavity system ofM. tuberculosis trHbO by means of computer‐simulation techniques. We have computed the free‐energy profiles for ligand migration along three found tunnels in the oxy and deoxy w.t. and mutant trHbO proteins. Our results show that multiple‐ligand migration paths are possible and that several conserved residues such as TrpG8 play a key role in the ligand‐migration regulation. Proteins 2008. © 2008 Wiley‐Liss, Inc.
Enhancement of effective carrier velocity in AlGaN/GaN MOSHFETs with Al2O3 gate oxide
Authors: Stoklas R. , Gaži Š. , Gregušová D. , Novák J. , Kordoš P.
Published: April 2008

Transport properties of Al2O3/AlGaN/GaN MOSHFETs and their unpassivated HFET counterparts are investigated. The Al2O3 gate oxide is only 4 nm thick and prepared by an oxidation of sputtered Al layer. The saturation drain current increased from 430 mA/mm for the HFET to 600 mA/mm for the MOSHFET. A significant increase of the extrinsic transconductance was observed – the peak values were 71 mS/mm for the HFET and 140 mS/mm for the MOSHFET. The transconductance increase is attributed to an enhancement of the effective carrier velocity due to the suppression of trapping states and following change of the electric field distribution below/near the gate contact. The MOSHFET devices showed significantly lower frequency dispersion of their capacitance than the HFET counterparts. All these shows an importance of thin and/or ‘high‐κ’ gate oxides for the preparation of AlGaN/GaN MOSHFETs. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gross well‐width fluctuations in InGaN quantum wells
Authors: Oliver R. A. , Kappers M. J. , Humphreys C. J.
Published: April 2008

In our earlier studies, we showed that the InxGa1–xN quantum wells in some green‐emitting commercial light emitting diodes are highly non‐uniform, containing gross width fluctuations on a 50–100 nm lateral scale. We reproduced such fluctuations in a research laboratory context by either annealing the InxGa1–xN epilayer, or subjecting it to a temperature ramp prior to growth of the GaN cap. We showed that the width fluctuations relate to a network of interlinking InxGa1–xN strips, and that threading dislocations tend to intersect this network between the strips. Here we investigate whether such networks may also be formed under a range of other growth conditions. By examining very thin InxGa1–xN epilayers which are expected to be fully strained, and showing they form networks upon thermal treatment, we rule out any role of strain relaxation in network formation. By examining samples grown at temperatures up to 790 °C, with low indium contents, and observing the formation of a network structure, we eliminate the possibility that spinodal decomposition is involved in network formation. The growth conditions examined are relevant to blue and ultra‐violet light emitters, and we thus suggest that network structures may have broader implications than previously realised. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Human urinary metabolite profile of tea polyphenols analyzed by liquid chromatography/electrospray ionization tandem mass spectrometry with data‐dependent acquisition
Authors: Sang Shengmin , Lee Mao‐Jung , Yang Ill , Buckley Brian , Yang Chung S.
Published: April 2008

Tea is rich in polyphenols and has a variety of biological activities. In order to better understand the biological effects of tea constituents on human health, markers for their exposure and their metabolic fates are needed. Previously, we have characterized several catechin metabolites in the blood and urine, but more information on the metabolite profile of tea polyphenols is needed. In the present study, the human urinary metabolite profile of tea polyphenols was investigated using liquid chromatography/electrospray ionization tandem mass spectrometry with data‐dependent acquisition. With data‐dependent MS/MS analysis by collecting the MS2and MS3spectra of the most intense ions in the sample, we identified more than twenty metabolites of tea polyphenols from human urine samples. (–)‐Epigallocatechin (EGC) glucuronide, methylated EGC glucuronide, methylated EGC sulfate, (–)‐epicatechin (EC) glucruronide, EC sulfate, methylated EC sulfate, as well as the glucuronide and sulfate metabolites of the ring‐fission metabolites of tea catechins, 5‐(3′,4′,5′‐trihydroxyphenyl)‐γ‐valerolactone (M4), 5‐(3′,4′‐dihydroxyphenyl)‐γ‐valerolactone (M6) and 5‐(3′,5′‐dihydroxyphenyl)‐γ‐valerolactone (M6′), were the major human urinary metabolites of tea polyphenols. To our knowledge, this is the first report of the direct simultaneous analysis of the human urinary metabolite profile of tea polyphenols using single sample analysis. This method can also be used for thorough investigations of the metabolite profiles of many other dietary constituents. Copyright © 2008 John Wiley & Sons, Ltd.
Possible dopaminergic stimulation of locus coeruleus α1‐adrenoceptors involved in behavioral activation
Authors: Lin Yan , Quartermain David , Dunn Adrian J. , Weinshenker David , Stone Eric A.
Published: April 2008

α1‐Adrenoceptors of the locus coeruleus (LC) have been implicated in behavioral activation in novel surroundings, but the endogenous agonist that activates these receptors has not been established. In addition to the canonical activation of α1‐receptors by norepinephrine (NE), there is evidence that dopamine (DA) may also activate certain brain α1‐receptors. This study examined the contribution of DA to exploratory activity in a novel cage by determining the effect of infusion of various dopaminergic and adrenergic drugs into the mouse LC. It was found that the D2/D3 agonist, quinpirole, which selectively blocks the release of CNS DA, produced a dose‐dependent and virtually complete abolition of exploration and all movement in the novel cage test. The quinpirole‐induced inactivity was significantly attenuated by coinfusion of DA but not by the D1 agonist, SKF38390. Furthermore, the DA attenuation of quinpirole inactivity was blocked by coinfusion of the α1‐adrenergic receptor antagonist, terazosin, but not by the D1 receptor antagonist, SCH23390. LC infusions of either quinpirole or terazosin also produced profound inactivity in DA‐β‐hydroxylase knockout (Dbh −/−) mice that lack NE, indicating that their behavioral effects were not due to an alteration of the release or action of LC NE. Measurement of endogenous DA, NE, and 5HT and their metabolites in the LC during exposure to the novel cage indicated an increase in the turnover of DA and NE but not 5HT. These results indicate that DA is a candidate as an endogenous agonist for behaviorally activating LC α1‐receptors and may play a role in the activation of this nucleus by novel surroundings. Synapse 62:516–523, 2008. © 2008 Wiley‐Liss, Inc.
In vivoandin vitroethanol exposure in prenatal rat brain: GABABreceptor modulation on dopamine D1receptor and protein kinase A
Authors: Lee H.Y. , Naha N. , Li S.P. , Jo M.J. , Naseer M.L. , Park M.S. , Park T.J. , Chung B.C. , Kim M.O.
Published: April 2008

We have investigated the effects of prenatal ethanol exposure on GABABreceptors (GABABRs), protein kinase A (PKA), and DA D1receptor (DAD1R) expressions. GABAB1R and GABAB2R showed different age‐dependent expressions inin vivofetal rat forebrain from gestational days (GD) 15.5 to 21.5 upon 10% ethanol treatment to mother, with and without baclofen at a dose of 10 mg/kg body weight/day. The protein level changes could not be attributed to changes in the level of transcription since GABABR mRNA presented different expression patterns uponin vivoethanol treatment. Using in vitro cultivated cortical neurons from GD 17.5 fetuses, we also explored the modulatory effects of ethanol on PKA and DAD1R through GABABRs, under 50 μM baclofen and 100 μM phaclofen administrations, with or without 100 mM of ethanol treatment in the culture media. The results showed that 20 min ethanol treatment without baclofen or phaclofen had increasing effects on both the GABABRs. Further, baclofen and phaclofen administration significantly affected PKA and GABABR levels upon 20 min and 1 h ethanol treatment. In contrast, DAD1R showed increasing effects upon ethanol treatment, which was modulated by GABABR's agonist baclofen and antagonist phaclofen. Therefore the present study suggested that the GABABR activity could modulate ethanol's cellular effects, which possibly including PKA and DAD1R activities, and may be an underlying cause of ethanol's effects. Synapse 62:534–543, 2008. © 2008 Wiley‐Liss, Inc.