bluuebunny/crossref_metadata_2025 huggingface dataset:
Moving knowledge of global burden into preventive action
Authors: Eijkemans Gerry J.M. , Takala Jukka
Published: November 2005

Background

Estimation of the global burden of disease and injury due to selected occupational factors is a topic of interest to policy makers, governments, and international bodies. The World Health Organization (WHO) has implemented a Comparative Risk Assessment (CRA) to estimate risk to exposed populations.

Methods

Estimates of the risk factor‐burden relationships by age, sex, and WHO subregion were generated. Risk measurements (relative risks and mortality rates) for the health outcomes were determined primarily from studies published in peer review journals. The resulting burden was described as the attributable fraction of disease or injury, using both mortality and disability‐adjusted life years (DALYs).

Results

The papers in this issue include discussions of worldwide mortality and morbidity from lung cancer, leukemia, and malignant mesothelioma arising from occupational exposures; mortality and morbidity from asthma, COPD, and pneumoconiosis; the global burden of low back pain; exposure to contaminated sharps injuries among health care workers; noise‐induced hearing loss; and occupational injuries. Three papers focus on economic issues: estimation of net‐costs for prevention of occupational low back pain; cost effectiveness of occupational health interventions; and the cost effectiveness of interventions in the prevention of silicosis.

Conclusions

The magnitude of the occupational health burden in the world is overwhelming, and the causes and mechanisms are multiple and complex. Commitment from all stakeholders is imperative to translate economic progress into sustainable human development and well‐being. Am. J. Ind. Med. 48:395–399, 2005. © 2005 Wiley‐Liss, Inc.
Estimation of the global burden of disease attributable to contaminated sharps injuries among health‐care workers
Authors: Prüss‐Üstün Annette , Rapiti Elisabetta , Hutin Yvan
Published: November 2005

Background

The global burden of hepatitis B (HBV), hepatitis C (HCV), and human immunodeficiency virus (HIV) infection due to percutaneous injuries among health care workers (HCWs) is estimated.

Methods

The incidence of infections attributable to percutaneous injuries in 14 geographical regions on the basis of the probability of injury, the prevalence of infection, the susceptibility of the worker, and the percutaneous transmission potential are modeled. The model also provides the attributable fractions of infection in HCWs.

Results

Overall, 16,000 HCV, 66,000 HBV, and 1,000 HIV infections may have occurred in the year 2000 worldwide among HCWs due to their occupational exposure to percutaneous injuries. The fraction of infections with HCV, HBV, and HIV in HCWs attributable to occupational exposure to percutaneous injuries fraction reaches 39%, 37%, and 4.4% respectively.

Conclusions

Occupational exposures to percutaneous injuries are substantial source of infections with bloodborne pathogens among health‐care workers (HCWs). These infections are highly preventable and should be eliminated. Am. J. Ind. Med. 48:482–490, 2005. © 2005 Wiley‐Liss, Inc.
Surface resistivity and rheological behaviors of carboxylated Multiwall carbon nanotube‐filled PET composite film
Authors: Ho Shin Dae , Han Yoon Kwan , Hyeong Kwon Oh , Ghyl Min Byung , Ik Hwang Chang
Published: November 2005

Multiwalled carbon nanotube (MWNT) nanocomposites with poly(ethylene terephthalate) (PET) were prepared via in situ polymerization. The refluxing time was more important factor than the sonication time for giving carboxylic groups onto the surface of MWNT. Acid‐MWNT prepared was well dispersed in ethylene glycol, whereas the neat‐MWNT agglomerated and sedimented at the bottom. The viscosity of the composites increased with the addition of MWNT, but PET/acid‐MWNT composite showed lower viscosity than PET/neat‐MWNT because of the damage of MWNT by acid treatment and copolymerization effect by the reaction between carboxylic groups of MWNT and PET. PET/acid‐MWNT composite film showed lower surface resistivity than PET/neat‐MWNT composite film. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 900–904, 2006
Temperature and pH‐response swelling behavior of poly(2‐ethyl‐2‐oxazoline)/chitosan interpenetrating polymer network hydrogels
Authors: Kim Seon Jeong , Lee Ki Jung , Kim In Young , Shin Dong Ik , Kim Sun I.
Published: November 2005

Interpenetrating polymer network (IPN) hydrogels composed of poly(2‐ethyl‐2‐oxazoline) (PEtOz) and chitosan (CS) were prepared with radical polymerization and were characterized for their swelling properties. Sample OC11 (hydrogel weight ratio PEtOz/CS = 1/1) swelled more than samples OC21 (PEtOz/CS = 2/1) and OC31 (PEtOz/CS =3/1), exhibiting a swelling ratio of about 2000 wt % in deionized water; the swelling ratios of the other samples were about 1000 and 700 wt %. The swelling behavior of the IPN hydrogels was observed under various pH and temperature conditions. The swelling ratios of the samples ranged from about 2000 to 6500 wt % at lower pHs, with a maximum swelling ratio of about 6500 wt % in a pH 2 aqueous solution. They exhibited low critical solution temperature behavior, with sample OC31 more sensitive to temperature and sample OC11 more sensitive to pH. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1100–1103, 2006
Morphology and thermal stability of BR/clay composites prepared by a new method
Authors: Wang Shaohui , Zhang Yong , Peng Zonglin , Zhang Yinxi
Published: November 2005

A new potential preparation method named in situ organic modification was used to prepare intercalated polybutadiene rubber (BR)/clay/dimethyl dihydrogenated tallow ammonium chloride (DDAC) composites. That is, BR, pristine clay, and intercalatant DDAC were directly mixed in a Haake rheometer without pretreating the pristine clay with the intercalatant. The morphology of the BR/clay composites was investigated by means of X‐ray diffraction and scanning electron microscopy. The thermal stability of the BR/clay composites was analyzed by thermogravimetric analysis (TGA). The dispersion of clay particles in the BR/clay/DDAC composites is much better than that in the BR/pristine clay and similar to that in the BR/organoclay DK4 (modified with DDAC) composites. BR/clay/DDAC composites have much higher thermal stability than the gum BR, BR/pristine clay, and BR/DK4 composites. The clay/intercalatant ratio has little influence on the thermal stability of the BR/clay/DDAC composites, while clay content has a significant effect on their thermal stability. The enhanced thermal stability of the BR/clay/DDAC composites is related to the dispersion state of clay particles in BR. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 905–913, 2006
Methylmethacrylate polymerization photoinitiated by 1‐(bromoacetyl)pyrene
Authors: Daswal Swati , Mishra Anuradha
Published: November 2005

The photopolymerization of methylmethacrylate induced by pyrene, 1‐acetylpyrene (AP), and 1‐(bromoacetyl)pyrene (BP) has been investigated. Under all conditions employed, pyrene was completely ineffective. Introduction of a carbonyl and a bromo group in pyrene enhanced the polymerization efficiencies. Efficiency of AP as photoinitiator was very low; however, BP was proved to be a good photoinitiator. The polymerization with BP follows first‐order kinetics with respect to monomer conversion, with a shorter induction period as compared with that of AP. The value of the initiator exponent (0.5) and the linear dependence of reciprocal average degree of polymerization on the square root of the initiator concentration suggest radical polymerization with bimolecular termination. IR and NMR spectra showed the atactic nature of polymethylmethacrylate. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 920–926, 2006
Rheological and thermogravimetric studies of the crosslinking process of functionalized acrylic latexes
Authors: Fourdrin Sylvie , Rochery Maryline , Lewandowski Maryline , Ferreira Manuela , Bourbigot Serge
Published: November 2005

Acrylic latexes are among one of the most widely used binders in the chemical bonding of textile nonwovens. This article investigates the crosslinking process of functionalized acrylic latices to understand the binder behavior during the processing of nonwovens and in the final product. Two techniques are used: rheology, to follow the structural development within the latex polymer, and thermogravimetry, to investigate the reaction through the weight loss resulting from the formation of evolving side products. The work has been carried out on latices functionalized by two crosslinking agents: N‐methylol acrylamide (NMA) and N‐methylol methacrylamide (NMMA). The results highlight the importance of the nature of the crosslinking agent, especially, its hydrophilic character, and the influence of the pH of the latex dispersions on the crosslinking mechanism, as well as on the final mechanical properties of the latex films. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1117–1123, 2006
Effect of vulcanization technique on the physical properties of silica‐filled EPDM rubber
Authors: Das Amit , De Debapriya , Naskar Nityananda , Chandra Debnath Subhas
Published: November 2005

The present study aims to enhance EPDM rubber–silica interaction by employing a special technique called Two‐Stage Vulcanization, with the help of a multifunctional rubber additive, bis diisopropyl thiophosphoryl disulfide (DIPDIS). In this process EPDM rubber was heated along with rubber additives up to the time just before the commencement of cure and then filler was incorporated to the preheated rubber to get the final mix. The efficiency of this novel technique is evaluated by the enhancement of physical properties of the silica‐filled vulcanizates. This novel technique is also employed to investigate the effect of a silane‐coupling agent, viz., bis (3‐triethoxy silyl propyl) tetrasulphide (TESPT), in addition to DIPDIS, on the rubber–filler interaction. The positive role of this technique in enhancing the rubber–filler interaction is evidenced by the dynamic mechanical analysis and scanning electron microscopy. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1132–1139, 2006
The research of RATRP of styrene in the microemulsion
Authors: Feng Haike , Dan Yi
Published: November 2005

In this paper, the reverse atom transfer radical polymerization of styrene in microemulsion was studied and some small molecular electrolyte was introduced into the microemulsion to limit the content of transition‐metal in the aqueous medium by salt effect and to control the molecular weight well ulteriorly. The polymerization was carried out at 80°C, with a mechanical agitator, using 2,2′‐A20‐bisbutyro‐nitrile (AIBN) as initiator and CuCl2/bpy as catalyst, under N2 atmosphere. Effects of the mole ratio of AIBN/CuCl2/bpy, the kind and content of small molecular electrolyte on the molecular weight of the polymers, and convention of the monomer were investigated through viscosity measurement, gel permeation chromatography, and transmission electronic microscope. The results show that adding CuCl2/bpy to the reactive system could control the increase of the molecular weight and the conversion effectively. The molecular weight and conversion would decrease with the increase of amount of CuCl2. When the mole ratio of AIBN/CuCl2/bpy is 1:2:6, the molecular weight is no more than 18 × 104. Adding NaCl or NaBr could make the molecular weight and conversion decrease too. A linear relationship between the molecular weight and the conversion can be obtained when the amount of NaCl or NaBr reaches 1.0% to water. The distribution index of molecular weight of the system with NaCl is narrower than that of system without NaCl. What's more, latex particles' shape is spherical whose diameter is from 10 to 100 nm. All researches we have laid a foundation for further study. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1093–1099, 2006
Optimization of PE/Binder/PA extrusion blow‐molded films. I. Heat sealing ability improvement using PE/EVA blends
Authors: Poisson C. , Hervais V. , Lacrampe M. F. , Krawczak P.
Published: November 2005

The optimization of three‐layer films (PE/binder/PA) manufactured by extrusion blow molding presents significant industrial challenges. The main issue consists in combining use properties (e.g., impermeability to water steam and oxygen, welding properties) with high mechanical, optical, and adhesion performances, while maintaining cost‐effectiveness. This article shows that the introduction of EVA in the PE layer improves the heat sealing ability and optical properties without degradation of the mechanical and adhesion performances. In the most favorable case, this modification leads to a 40% reduction of the heat sealing time, the other performances remaining either identical or higher. This leads to cost reduction of this manufacturing step while improving the flexibility of the process (wider process temperature window). The properties modifications observed can be explained by microstructure modifications (crystallinity, orientation, and molecular mobility). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 974–985, 2006
Metallocene‐catalyzed olefin polymerization using magnesium chloride‐supported borate activators
Authors: Smit M. , Severn J. R. , Zheng X. , Loos J. , Chadwick J. C.
Published: November 2005

New approaches have been identified for the immobilization, on a MgCl2‐based support, of borate activators for metallocene‐catalyzed olefin polymerization. Immobilization of [HNEt3][B(C6F5)3(C6H4‐4‐OH)] was carried out by reaction with a support of type MgCl2/AlRn(OEt)3−n, obtained by reaction of AlEt3 with an adduct of magnesium chloride and ethanol. Use of the resulting immobilized borate in combination with zirconocene catalysts in ethylene and propylene polymerization resulted in significantly higher polymerization activities than were obtained using the same borate immobilized on a silica support. The MgCl2‐based support also gave the better polymer particle morphology, cross‐sectional imaging indicating uniform support fragmentation, as opposed to incomplete fragmentation using the silica support. High catalyst activities were obtained using a MgCl2/AlRn(OEt)3−n support impregnated with [Ph3C][B(C6F5)4]. In this case, a highly porous polyethylene particle morphology was obtained. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 986–993, 2006
Mechanical relaxations of poly(β,L‐aspartate)s
Authors: Ramis Xavier , García‐Alvarez Montserrat , Muñoz‐Guerra Sebastián
Published: November 2005

The dynamic mechanical thermal properties of a family of poly(α‐alkyl β,L‐aspartate)s bearing various cyclic, linear, and branched alkoxycarbonyl groups in the side chain were studied. The measurements carried out by dynamic mechanical thermal analysis (DMTA) revealed the significant influence of the constitution of the side chain on mechanical relaxation phenomena. Three relaxations were observed, which are referred to as γ, β, and α, in increasing order of temperature. The first two, γ and β, are related to the local and global motions of the side chain, respectively. Relaxation α is related to the motion of the main chain. Relaxation β, which is associated with the rotation of the side chain, is the most intense. The magnitude and temperature at which this relaxation occurs depends on the volume, the length, and the degree of branching of the ester group of the side chain. A comparison between the dynamic mechanical properties of poly(β,L‐aspartate)s and poly(α,L‐glutamate)s revealed that the two methylene groups spacing the ester group from the main chain provides the poly(α‐L‐glutamate)s with greater mobility, and thus, relaxations α and β occur at lower temperatures. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 994–1003, 2006
The synthesis and application of Pb‐doped GLYMO/chelated‐zirconium complex coating materials for UV‐light absorption
Authors: Asiltürk Meltem , Sayılkan Funda , Sayılkan Hikmet , İçduygu Galip
Published: November 2005

New glass coating materials containing γ‐glycidoxypropyltrimethoxy‐silane/zirconium(IV)‐n‐propoxide(2‐methoxyethylacetoacetate)/lead(II) nitrate were developed for UV‐light absorption by sol‐gel process. The effect of agitation time, temperature, and Zr complex and Pb2+ ion concentrations on UV light absorption were investigated. Zr complex was characterized by using 1H‐NMR, 13C‐NMR, and FTIR spectroscopy. Ultraviolet visible spectroscopy was utilized to determine the optical properties of coating materials. Results showed that coated glass has very low transmission in the UV region (300–400 nm) relative to uncoated glass, especially at 150°C for 15 h agitation. UV light transmission of coated glasses treated at 80, 100, 450, or 500°C was not different from uncoated glass. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1175–1179, 2006
Nano‐addition of raw bentonite enhances polypropylene (PP) properties
Authors: Kulshreshtha A. K. , Maiti A. K. , Choudhary M. S. , Rao K. V.
Published: November 2005

Bntonite (BNT) is the cheapest raw material source for making commercial nanoclay, which is approximately 250 times more expensive than BNT. Perhaps this may be one of the reasons why we do not find a translation of good scientific work on polymer nanocomposites into commercial reality. In this work, it is demonstrated that PP nanocomposites were made using 3% raw bentonite via Master batch (MB) route with maleated PP. This product has 9.5% greater tensile strength, 18.6% greater flexural strength, and 27% greater flexural modulus than neat PP. The repeat extrusion of PP/bentonite was carried out, which had beneficial effects on tensile modulus and flexural strength and less so on other properties. This study opens a Pandora's box full of possibilities, such as cheap polymer nanocomposites being available for many different applications. Increase in the previously mentioned properties of PP‐BNT adduct cannot be explained by the nucleation effect of BNT on PP. X‐ray diffraction, internal surface area, TGA, and DSC measurements were made on the above samples. Addition of 3% raw bentonite increases the crystallization of PP by 7.5°C (nucleation effect). Since this is just a pilot study, this opens a vast commercial scope for making nanocomposites from raw clays. The stakes for doing this are very high, because BNT is $0.10/kg and can be available consistently from mineral producers in Gujarat and Rajasthan in India. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1004–1009, 2006
Chelating polymer granules prepared by radiation‐induced homopolymerization. II. Characterizations
Authors: Badawy Sayed M. , Sokker Hesham H. , Dessouki Ahmed M.
Published: November 2005

Characterizations of chelating polymer adsorbent granules, incorporating amidoxime groups based on polyacrylonitrile (PAN), prepared for selective adsorption of uranium and likely other transition metals were studied. PAN was prepared by radiation‐induced polymerization technique and followed by amidoximation reaction. Conversion of PAN into polyacrylamidoxime (PAO) was studied by fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Morphology and thermal properties were also investigated. PAO was investigated in the separation of uranium from iron‐rich silicate rock samples and subjected to x‐ray fluorescence analysis (XRF). Selective adsorption for uranium and low affinity for alkali and alkaline earth metals were observed. The order of selectivity was found to be U ≫ Cu > Fe > Ni > Cr > V ≫ Ca > K. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1180–1187, 2006
The effects of acrylate monomers and polystyrene addition on the morphology of DOP‐plasticized styrene–acrylate polymer particles prepared by SPG emulsification and suspension polymerization
Authors: Nuisin Roongkan , Omi Shinzo , Kiatkamjornwong Suda
Published: November 2005

Fairly uniform copolymer particles of methyl acrylate (MA), butyl acrylate (BA), or butyl methacrylate (BMA) were synthesized via Shirasu porous glass (SPG) membrane and followed by suspension polymerization. After a single‐step SPG emulsification, the emulsion composed mainly of the monomers. Hydrophobic additives of dioctyl phthalate (DOP), polystyrene molecules, and an oil‐soluble initiator, suspended in an aqueous phase containing poly(vinyl alcohol) (PVA) stabilizer and sodium nitrite inhibitor (NaNO2), were subsequently subjected to suspension polymerization. Two‐phase copolymers with a soft phase and a hard phase were obtained. The composite particles of poly(St‐co‐MA)/PSt were prepared by varying the St/PSt ratios or the DOP amount. The addition of PSt induced a high viscosity at the dispersion phase. The molecular weight slightly increased with increasing St/PSt concentration. The multiple‐phase separation of the St‐rich phase and PMA domains, observed by transmission electron microscopy, was caused by composition drift because the MA reactivity ratio is greater than that of St. The addition of DOP revealed the greater compatibility between the hard‐St and soft‐MA moieties than that without DOP. The phase morphologies of poly(St‐co‐MA), poly(St‐co‐BMA), and their composites with PSt were revealed under the influence of DOP. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1195–1206, 2006
Polymer nanofibers prepared by template melt extrusion
Authors: Li Huayi , Ke Yucai , Hu Youliang
Published: November 2005

Combining the template method with the extrusion technology, polymer nanofibers have been prepared when molten polymer is forced through the pores of anodic aluminum membrane and cooled to complete the nanofiber formation process. The microstructures of nanofibers are determined by SEM, TEM, XRD, and DSC. The results suggest that the PE nanofibers consist of extended‐chain crystals and the transition from an orthorhombic to a hexagonal phase and the latter phase melting occurs at 159.8°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1018–1023, 2006
The effects of excimer laser irradiation at 248 nm on the surface mass loss and thermal properties of PS, ABS, PA6, and PC polymers
Authors: Sancaktar Erol , Lu Hui
Published: November 2005

Excimer laser irradiation provides a new and important method for polymer surface treatment. In this work, the weight loss of engineering polymers PC, ABS, PS, and nylon 6 were investigated following irradiation by KrF excimer laser. The experimental results revealed that the polymeric weight loss is nonlinearly related to the laser energy and laser frequency for most of the materials tested. The effects of laser irradiation on the thermal properties (Tg or Tm) of the polymers were investigated using DSC. It was found that the Tg and Tm of these materials decreased as a result of laser treatment, indicating the degradation effect of the laser irradiation procedure. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1024–1037, 2006
Effect of solution properties on nanofibrous structure of electrospun poly(lactic‐co‐glycolic acid)
Authors: You Young , Lee Seung Jin , Min Byung‐Moo , Park Won Ho
Published: November 2005

Electrospinning of poly(lactic‐co‐glycolic acid) (PLGA) in chloroform or 1,1,1,3,3,3‐hexafluoro‐2‐propanol (HFIP) was investigated, focusing on its solution parameters, to develop nonwoven biodegradable nanofibrous structures for tissue engineering. PLGA nanofibers were obtained by electrospinning of 15 wt % PLGA solution and the resulting average fiber diameters were varied with the range of 270–760 nm, depending on solution property. When small amounts of benzyl triethylammonium chloride (BTEAC) was added to the PLGA/chloroform solution, the average diameter was decreased from 760 to 450 nm and the fibers were densely amounted in a straight shape. In addition, the average fiber diameter (270 nm) of nanofibers electrospun from polar HFIP solvent was much smaller than that (760 nm) of nanofibers electrospun from nonpolar chloroform solvent. Therefore, it could be concluded that conductivity or dielectric constant of the PLGA solution was a major parameter affecting the morphology and diameter of the electrospun PLGA fibers. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1214–1221, 2006
Main‐chain chiral smectic liquid‐crystalline ionomers containing sulfonic acid groups
Authors: Tian Mei , Zhang Bao‐Yan , Meng Fan‐Bao , Zang Bao‐Ling
Published: November 2005

Three series of main‐chain liquid‐crystalline polymers (P1, P2, and P3) were synthesized by an interfacial condensation reaction of sebacoyl dichloride with various amount of brilliant yellow, isosorbide, and 4,4′‐biphenydiol. P1 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol and isosorbide. P2 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol, brilliant yellow, and isosorbide. P3 series are polyesters prepared from sebacoyl chloride and various amount of 4,4′‐biphenyldiol and brilliant yellow. P2 and P3 are main‐chain liquid‐crystalline ionomers. P12 and P3 series were prepared as model polymers for comparison with the liquid crystalline behavior of ionomers, P2 series. The structures of the polymers were characterized by IR and UV spectroscopy. Differential scanning calorimetry was used to measure the thermal properties of the polymers. The mesogenic properties were investigated by polarized optical microscope, differential scanning calorimetry, and X‐ray diffraction measurements. The results show that P2 series are chiral smectic C (SmC*) and chiral smectic B (SmB*) liquid crystalline ionomers exhibiting broken focal‐conic texture and schlieren, as is the polymer P12, which has the same amount of 4,4′‐biphenydiol and isosorbide. The introduction of ionic units in P2 series leads to an increase of clearing point, but has not affected the mesogenic type and texture, as compared with the corresponding polymer P12. The introduction of chiral units in P2 series leads to a change of mesophase, as compared with P3 series, which exhibit smectic C mesogetic phase. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1254–1263, 2006
Polycondensation reaction of N,N′‐(4,4′‐oxydiphthaloyl)‐bis‐L‐methionine diacid chloride with aromatic diamines: Synthesis and properties
Authors: Mallakpour Shadpour , Kowsari Elaheh
Published: November 2005

Several new optically active poly(amide‐imide)s have been synthesized by solution polycondensation of readily available aromatic diamines with diacid chloride containing ether‐imide and L‐methionine moieties. Three polycondensation techniques were used: low temperature solution polycondensation, short period reflux conditions, and microwave‐assisted polycondensation. In all cases, the reactions were carried out using equimolecular amounts of the two monomers, in polar aprotic solvents. The obtained compounds were characterized by elemental analysis, solubility tests, FTIR, and 1H NMR spectrometry. Thermal stability of the polymer was studied by thermogravimetric analysis. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1038–1044, 2006
Atom transfer radical polymerization of acrylonitrile
Authors: Hou Chen , Ying Liang , Wang Chengguo
Published: November 2005

Iron(II) chloride coordinated by succinic acid was first used as the catalyst in 2‐chloropropionitrile‐initiated atom transfer radical polymerization (ATRP) of acrylonitrile. N,N‐dimethylformamide was used as a solvent to improve the solubility of the ligand. An iron(II) chloride to succinic acid ratio of 0.5 not only gives the best control of molecular weight and its distribution but also provides rather rapid reaction rate. Effects of solvent on polymerization of acrylonitrile were also investigated. The induction period is shorter in N,N‐dimethylformamide than in propylene carbonate and toluene and the rate of the polymerization in N,N‐dimethylformamide is fastest. The molecular weight of polyacrylonitrile agrees reasonably well with the theoretical molecular weight of N,N‐dimethylformamide. The rate of polymerization increases and the induction period becomes shorter with increasing polymerization temperature, and the apparent activation energy was calculated to be 56.5 kJ mol−1. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1050–1054, 2006
New melamine–formaldehyde–ketone polymers. III. Coatings from melamine and reactive solvents based on cyclohexanone
Authors: Głowacz‐Czerwonka Dorota , Kucharski Mieczysław
Published: November 2005

The conditions and methods of preparing novel melamine–formaldehyde–cyclohexanone coatings are presented. The coatings were prepared by dissolving melamine in reactive solvents based on formaldehyde and cyclohexanone. The latter were prepared at different molar ratios of the components. The water resistance of the resulting coatings was measured. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1083–1092, 2006
Polyaniline–nylon 6 composite nanowires prepared by emulsion polymerization and electrospinning process
Authors: Hong Kyung Hwa , Kang Tae Jin
Published: November 2005

Polyaniline (PANI) nanoparticles doped with the dodecylbenzene sulfonic acid (DBSA) were prepared and these nanoparticles were electrospun with nylon 6 as matrix material into fiber web. Depending on the contents and concentrations of PANI and nylon 6, either nylon 6 nanofibers (∼96 nm) or PANI‐nylon 6 composite nanofibers (∼12 nm) were obtained. The electrical conductivity of PANI(DBSA)–nylon 6 electrospun fiber web was lower than that of PANI(DBSA)‐nylon 6 film because of the low crystallinity of the PANI(DBSA)–nylon 6 composite electrospun fiber web. However, it showed that the PANI–nylon 6 composite nanofibers would have applications as the nanowires for connecting the microelectromechanical system (MEMS). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1277–1286, 2006
Regulating the regulator: the control of auxin transport
Authors: Benjamins René , Malenica Nenad , Luschnig Christian
Published: November 2005

With the discovery of the phytohormone auxin in the late 1920s, it became possible to link the regulation of complex plant growth responses to a single biologically active compound. Among all the plant growth regulators characterised so far, only auxin appears to be actively transported throughout the plant to create complex variations in concentration patterns and flow directions over time. This stimulated interest in the specific mechanisms underlying auxin transport as key factors in plant growth responses. Research in the last decade revealed several genes involved in the controlled transport of auxin and greatly improved our understanding of the basic principles of auxin‐mediated responses. We are at this point, however, only starting to understand the complex interplay and control of factors that ultimately underlie the observed spatiotemporal variations in auxin transport and thus mediate plant growth and environmental responses. This review highlights important findings that provide us with a framework of molecular players and potential regulatory mechanisms that should contribute to the formulation of a comprehensive dynamic model of spatiotemporal auxin distribution. BioEssays 27:1246–1255, 2005. © 2005 Wiley Periodicals, Inc.
Fundamental issues in systems biology
Authors: O'Malley Maureen A. , Dupré John
Published: November 2005

In the context of scientists' reflections on genomics, we examine some fundamental issues in the emerging postgenomic discipline of systems biology. Systems biology is best understood as consisting of two streams. One, which we shall call ‘pragmatic systems biology’, emphasises large‐scale molecular interactions; the other, which we shall refer to as ‘systems‐theoretic biology’, emphasises system principles. Both are committed to mathematical modelling, and both lack a clear account of what biological systems are. We discuss the underlying issues in identifying systems and how causality operates at different levels of organisation. We suggest that resolving such basic problems is a key task for successful systems biology, and that philosophers could contribute to its realisation. We conclude with an argument for more sociologically informed collaboration between scientists and philosophers. BioEssays 27:1270–1276, 2005. © 2005 Wiley Periodicals, Inc.
Nitric oxide and metastatic cell behaviour
Authors: Williams Emma L. , Djamgoz Mustafa B.A.
Published: November 2005

Nitric oxide (NO) is a pleiotropic signalling molecule that subserves a wide variety of basic cellular functions and also manifests itself pathophysiologically. As regards cancer and its progression, however, the reported role of NO appears surprisingly inconsistent. In this review, we focus on metastasis, the process of cancer cell spread and secondary tumour formation. In a ‘reductionist’ approach, we consider the metastatic cascade to be made up of a series of basic cellular behaviours (such as proliferation, apoptosis, adhesion, secretion migration, invasion and angiogenesis). We evaluate how NO controls such behaviours, in comparison with normal cells. The available information suggests strongly that NO signalling would be expected to regulate these behaviours both positively and negatively and this probably leads to the observed apparent variability in the NO status of cancer cells and tissues. Thus, the role of NO in cancer is more complex than previously thought. A number of suggestions are made, including consideration of novel mechanisms, such as ion channels, in order to achieve a more consistent and integrated understanding of NO signalling in cancer and to realise its clinical potential. BioEssays 27:1228–1238, 2005. © 2005 Wiley Periodicals, Inc.
Memory mechanisms of active transcription during cell division
Authors: Zhou Guo‐Ling , Liu De‐Pei , Liang Chih‐Chuan
Published: November 2005

The developmental programs of eukaryotic organisms involve the programmed transcription of genes. A characteristic gene expression pattern is established and preserved in each different cell type. Therefore, gene activation at a particular time and its maintenance during cell division are significant for cellular differentiation and individual development. Although many studies have sought to explain the molecular mechanisms of gene expression regulation, the mechanism through which gene expression states are inherited during cell division has not been fully elucidated yet. This review illustrates the general principles and the complexities involved in the establishment and maintenance of active transcription through cell cycles. It focuses on the most‐recent findings about the ways in which molecular memory marks for active transcription are coordinated with cell cycle events, such as replication, mitosis and nuclear organization, to mediate transcription memory across cell division events, which may establish a unifying memory process of active transcription. BioEssays 27:1239–1245, 2005. © 2005 Wiley Periodicals, Inc.
Global analysis of siRNA‐mediated transcriptional gene silencing
Authors: Kavi Harsh H. , Xie Weiwu , Fernandez Harvey R. , Birchler James A.
Published: November 2005

The RNAi machinery is not only involved with post‐transcriptional degradation of messenger RNAs, but also used for targeting of chromatin changes associated with transcriptional silencing. Two recent papers determine the global patterns of gene expression and chromatin modifications produced by the RNAi machinery in fission yeast.(9, 10) The major sites include the outer centromere repeats, the mating‐type locus and subtelomeric regions. By comparison, studies of Arabidopsis heterochromatin also implicate transposons as a major target for silencing. Analyses of siRNA libraries from Drosophila, nematodes and Arabidopsis indicate that major repeats at centromeres, telomeres and transposable elements are likely targets of RNAi. Also, intergenic regions are implicated as targets in Arabidopsis. BioEssays 27:1209–1212, 2005. © 2005 Wiley Periodicals, Inc.
The epigenetic basis for embryonic stem cell pluripotency
Authors: Szutorisz Henrietta , Dillon Niall
Published: November 2005

As well as having the remarkable ability to differentiate into all of the cell types in the embryo, embryonic stem (ES) cells also have the capacity to divide and self‐renew. Maintenance of pluripotency through repeated cell divisions indicates that the developmental plasticity of ES cells has a specific epigenetic basis. We propose that tightly localised regions of histone modification are formed in ES cells by binding of sequence‐specific transcription factors at genes that are destined for expression at later stages of differentiation. These ‘early transcription competence marks’ would help to maintain pluripotency by preventing the spread of repressive chromatin modifications. We further propose that the presence of discrete histone modification marks in pluripotent cells facilitates the binding of lineage‐specific and general transcription factors to the marked regions as ES cells commit to different fates. By helping to organise the precisely timed responses of genes to the signals that determine lineage choice, the gene‐specific localised epigenetic marks would play a key role in the establishment of complex gene expression programmes in differentiating cells. BioEssays 27:1286–1293, 2005. © 2005 Wiley Periodicals, Inc.
Synthesis of Strained Tricyclic β‐Lactams by Intramolecular [2+2] Cycloaddition Reactions of 2‐Azetidinone‐Tethered Enallenols: Control of Regioselectivity by Selective Alkene Substitution
Authors: Alcaide Benito , Almendros Pedro , Aragoncillo Cristina , Redondo María C. , Torres M. Rosario
Published: November 2005

A convenient metal‐free methodology for the preparation of structurally novel, strained tricyclic β‐lactams containing a cyclobutane ring has been developed. The first examples accounting for the intramolecular [2+2] cycloaddition reactions in β‐lactams have been achieved by the thermolysis of 2‐azetidinone‐tethered enallenols, which have been prepared in aqueous media by regio‐ and diastereoselective indium‐mediated carbonyl allenylation of 4‐oxoazetidine‐2‐carbaldehydes. Notably, the regioselectivity of the cycloaddition can be tuned in the allene component just by a subtle variation in the substitution pattern of the alkene component.
Synthesis of Donor–Acceptor Alkynylcyclopropanes by Diastereoselective Cyclopropanation of Electron‐Deficient Alkenes with Alkoxyalkynyl Fischer Carbene Complexes
Authors: Barluenga José , Fernández‐Rodríguez Manuel A. , García‐García Patricia , Aguilar Enrique , Merino Isabel
Published: November 2005

The reaction of electron‐deficient alkenes with alkoxyalkynyl Fischer carbene complexes (FCCs) represents a straightforward route to a new type of captodative (donor–acceptor) alkynylcyclopropanes, which have been prepared in moderate to high yields and in a diastereoselective manner. Some studies regarding the employment of additives to facilitate the recovery of the metal moiety after the reaction are also described. Finally, the first example of a cyclopropanation reaction through employing Fischer carbene complexes under microwave irradiation is presented; this method proved to be an advantageous alternative to the thermal reaction.
Water‐Soluble Fluorescent Boronic Acid Compounds for Saccharide Sensing: Substituent Effects on Their Fluorescence Properties
Authors: Zhang Yanling , Gao Xingming , Hardcastle Kenneth , Wang Binghe
Published: November 2005

Four new naphthalene‐based boronic acid compounds (1–4) were synthesized. The effect of various carbohydrates on their fluorescence properties has been studied in aqueous phosphate buffer at pH 7.4. Different substitutions on the aniline group of the naphthalene ring resulted in significant differences in fluorescence properties for these four compounds. Compound 1 shows ratiometric fluorescence changes upon addition of a sugar. Compounds 2 and 3 do not show ratiometric fluorescence changes but show very large fluorescence intensity changes (about 70‐fold fluorescence intensity increase). In addition to the quantifiable fluorescence property changes upon sugar addition, the fluorescence color changes of 1–3 are also visible to the naked eye. However, amidation of the aniline nitrogen atom significantly diminishes the fluorescence intensity of compound 4. The crystal structure of one boronic acid provided some insight into the structural features that are important for the fluorescence properties of these compounds.
Phase II study of weekly irinotecan plus capecitabine for chemotherapy‐naive patients with advanced nonsmall cell lung carcinoma
Authors: Han Ji‐Youn , Lee Dae Ho , Lee Sung Young , Park Chun Gun , Kim Hyae Young , Lee Hong Gi , Lee Jae Jin , Kim Heung Tae , Lee Jin Soo
Published: November 2005

BACKGROUND

A Phase II study was conducted to evaluate the efficacy and toxicity of an irinotecan plus capecitabine combination, a new nonplatinum regimen, in chemonaive patients with advanced nonsmall cell lung carcinoma (NSCLC).

METHODS

Between July 2003 and April 2004, 53 patients with a histologically confirmed diagnosis of NSCLC were enrolled. All but 5 patients were male, 52 (98%) had an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1, 39 (74%) had AJCC Stage IV disease, and the median age was 61 years. Treatment consisted of intravenous irinotecan at a dose of 90 mg/m2 on Days 1 and 8 and oral capecitabine at a dose of 1000 mg/m2 twice daily on Days 1–14 of each 21‐day cycle, given up to 12 cycles.

RESULTS

Of 53 patients enrolled, 22 achieved objective tumor responses (all partial responses) for an overall response rate of 41.5% (95% confidence interval [95% CI], 28.2–54.8%). After a median follow‐up of 17.4 months, the median survival was 14.6 months with a 1‐year survival rate of 60.1% (95% CI, 46.9–73.4%) and a median progression‐free survival of 5.1 months. Treatment was very well tolerated, with only 10% of patients experiencing NCI‐CTC Grade 3 or 4 toxicities. The most common toxicities were hand–foot syndrome and diarrhea. In multiple logistic regression analysis for overall response, only the stage predicted for significantly better response (P = 0.04). Squamous cell carcinoma was marginally predictive for better response (P = 0.08).

CONCLUSIONS

The irinotecan plus capecitabine regimen demonstrated an antitumor activity that is favorably comparable with other commonly used cisplatin‐based regimens. Given the mild toxicity profile and favorable survival outcome, this nonplatinum regimen warrants further evaluation in a randomized trial. Cancer 2005. © 2005 American Cancer Society.
Clinical trial of valproic acid and all‐trans retinoic acid in patients with poor‐risk acute myeloid leukemia
Authors: Bug Gesine , Ritter Markus , Wassmann Barbara , Schoch Claudia , Heinzel Thorsten , Schwarz Kerstin , Romanski Annette , Kramer Oliver H. , Kampfmann Manuela , Hoelzer Dieter , Neubauer Andreas , Ruthardt Martin , Ottmann Oliver G.
Published: November 2005

BACKGROUND

Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, induced in vitro differentiation of primary acute myeloid leukemia (AML) blasts, an effect enhanced by all‐trans retinoic acid (ATRA). Clinical responses to VPA were recently observed in patients with myelodysplastic syndrome (MDS). Herein, the authors have described results of a clinical trial with VPA plus ATRA in 26 patients with poor‐risk AML.

METHODS

VPA (5–10 mg/kg starting dose) and ATRA (45 mg/m2) were administered orally. Low‐dose AraC or hydroxyurea were permitted to control leukocytosis. Biologic activity of VPA was confirmed by serial analysis of HDAC2 protein levels in peripheral blood (PB) mononuclear cells.

RESULTS

Nineteen of 26 patients completed at least 4 weeks of VPA/ATRA treatment; 7 patients were withdrawn prematurely because of rapidly progressive disease (n = 3) or unacceptable neurologic and cardiovascular toxicity (n = 4). Additional cytoreductive treatment was required in 58% of patients enrolled. Median treatment duration was 3 months. No patient achieved complete remission, one with de novo AML had a minor response, and two patients with secondary AML arising from myeloproliferative disorder (MPD) achieved a partial remission and clearance of PB blasts, respectively. The latter responses were accompanied by profound granulocytosis and erythrocytosis in both patients, reminiscent of the response pattern known from ATRA treatment of acute promyelocytic leukemia. However, cytogenetic analysis of isolated CD34+ cells and granulocytes did not reveal terminal differentiation of leukemic blasts.

CONCLUSIONS

Treatment with VPA/ATRA results in transient disease control in a subset of patients with AML that has evolved from a myeloproliferative disorder but not in patients with a primary or MDS‐related AML. Cancer 2005. © 2005 American Cancer Society.
Capecitabine combined with gemcitabine (CapGem) as first‐line treatment in patients with advanced/metastatic biliary tract carcinoma
Authors: Cho Jae Yong , Paik Yong Han , Chang Yoon Soo , Lee Se Joon , Lee Dong‐Ki , Song Si Young , Chung Jae Bock , Park Mi‐Suk , Yu Jeong‐Sik , Yoon Dong‐Sup
Published: November 2005

BACKGROUND

Biliary tract carcinoma is an aggressive cancer, with median survival rarely exceeding 6 months. There is currently no established palliative standard of care. A Phase II trial was conducted to study a combination of oral capecitabine and gemcitabine (CapGem) as first‐line therapy in patients with advanced and/or metastatic biliary carcinoma.

METHODS

Patients with unresectable or metastatic intrahepatic or extrahepatic biliary duct carcinoma and gallbladder carcinoma were enrolled. Eligible patients had histologically or cytologically confirmed, measurable adenocarcinoma and had not received prior therapy with capecitabine or gemcitabine. Treatment consisted of intravenous (i.v.) gemcitabine (1000 mg/m2 on Days 1 and 8) plus oral capecitabine (650 mg/m2 twice daily on Days 1–14) every 3 weeks for up to 6 cycles. Tumor response, survival, and safety were determined.

RESULTS

A total of 44 patients were evaluable. Primary tumor sites were: intrahepatic (n = 14) and extrahepatic biliary duct (n = 16); gallbladder (n = 7); and ampulla (n = 7). Fourteen (32%) patients had a partial response and 15 (34%) patients had stable disease. Median time to disease progression and overall survival were 6.0 (range, 3.8–8.1) and 14 (range, 11.4–16.6) months, respectively. The 1‐year survival rate was 58%. No Grade 4 adverse events were seen. Transient Grade 3 neutropenia/thrombocytopenia and manageable (almost invariably Grade 2) nausea, diarrhea, and hand–foot syndrome were the most common adverse events.

CONCLUSIONS

CapGem is an active and well tolerated first‐line combination chemotherapy regimen for patients with advanced/metastatic biliary tract carcinoma that offers a convenient home‐based therapy. Cancer 2005. © 2005 American Cancer Society.
Influence of Coadsorbates on the NO Dissociation on a Rhodium(311) Surface
Authors: Inderwildi Oliver R. , Lebiedz Dirk , Deutschmann Olaf , Warnatz Jürgen
Published: November 2005

Density functional theory (DFT) studies were performed to investigate the influence of coadsorbates on the nitrogen oxide dissociation on the vicinal rhodium(311) surface. This study amplifies prior studies on the dissociation of oxygen and nitrogen oxide on the (111) facet of rhodium. The influence of coadsorbates on the kinetic parameters and thermochemistry of the NO dissociation on Rh(311) was studied. In addition, the activation energy and thermochemistry of this reaction were determined as a function of oxygen preoccupation/initial coverage. Steric and electronic effects and their influence on the dissociation reaction were examined. The results are discussed in the face of an NOx dissociation catalyst system proposed by Nakatsuji.