bluuebunny/crossref_metadata_2025 huggingface dataset:
Microencapsulation of a functional dye and its UV crosslinking controlled releasing behavior
Authors: Li Gangqiang , Guo Jinbao , Wang Xiao , Wei Jie
Published: June 2009

A new family of microcapsules containing photopolymerizable tripropylene glycol diacrylate (TPGDA) was synthesized by using interfacial polymerization. The release behavior of encapsulated dye could be controlled easily by changing the crosslink density of network formed from TPGDA. The chemical structure and properties of microcapsules were characterized by Fourier Transform infrared spectroscopy, scanning electron microscope, differential scanning calorimetry, optical microscope, wide angle X‐ray diffraction and UV‐visible spectrophotometer. The results demonstrate that the higher agitation rate results in a smaller particle size with a narrow size distribution. When core/shell ratio is low, the surface of the microcapsules becomes smooth. Additionally, it was found that UV radiation time is most effective factor to change the CC double bond conversion ratio. After microcapsules were synthesized, the release speed could be changed according to requirement by exposing them to UV light for minutes. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3630–3639, 2009
Blends of different linear polyamides with hyperbranched aromatic AB2 and A2 + B3 polyesters
Authors: Fan Zhirong , Jaehnichen Klaus , Desbois Philippe , Haeussler Liane , Vogel Roland , Voit Brigitte
Published: June 2009

To explore the possible applications of hyperbranched polymers for modifying linear polyamides, two hyperbranched aromatic polyesters characterized as high Tg polymers possessing phenolic end groups were used in melt mixing with partly aromatic polyamide and commercially available aliphatic polyamide‐6, respectively. Different amounts of both hyperbranched polyesters (from 1 wt % up to 20 wt %) were added to the polyamides, and the influence of these hyperbranched polyesters on the properties of the polyamides was investigated. The hyperbranched polyester based on an AB2 approach was found to be the most effective modifier. A significant increase of the glass transition temperature of the final blend was detected. However, a remarkable reduction of crystallinity as well as complex melt viscosity of those blends was also observed. The use of an A2+B3 hyperbranched polyester as melt modifier for the polyamides was less effective for changing the thermal properties, and the complex melt viscosity of the final material increased since heterogeneous blends were formed. In contrast to that, generally, the addition of the AB2 hyperbranched polyester to the polyamides resulted in homogeneous blends with improved Tg and processability. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3558–3572, 2009
Copolyfluorenes containing bridged triphenylamine or triphenylamine: Synthesis, characterization, and optoelectronic properties
Authors: Jiang Zuoquan , Zhang Wenjun , Yao Haiqing , Yang Chuluo , Cao Yue , Qin Jingui , Yu Gui , Liu Yunqi
Published: June 2009

A novel aryl‐bridged triphenylamine derivative, 7‐t‐butyl‐5,5,9,9‐tetraaryl‐13b‐aza‐naphtho[3,2,1‐de]anthracene (ABTPA) was designed and synthesized. The alternating copolymers of ABTPA/dihexylfluorene (P1) and triphenylamine (TPA)/dihexylfluorene (P2) were synthesized by Suzuki coupling reaction. P1 shows excellent thermal stability with a decomposition temperature of 440 °C and a glass‐transition temperature of 326 °C. The HOMO energy levels of the two polymers are very close (−5.15 eV for P1 and −5.13 eV for P2). The maximum absorption peak of P1 is red shifted by 23 nm with respect to P2, because the incorporation of ABTPA units into the PF backbone enhances the electronic conjugation degree compared with the case of TPA units. The rigidity and the steric hindrance of the ABTPA in P1 result in a small Stokes shift and almost the same emission spectra of P1 between its film and solution. A PLED with simple configurations of ITO/P1/TNS (tetranaphthalen‐2‐yl‐silane)/Alq3 (tris(8‐hydroxyquinolinolato)aluminum)/Al emits a blue light with emission peak at 436 nm, and exhibits a maximum current efficiency of 1.89 cd/A and a maximum luminance of 4183 cd/m2, which is superior to the device with P2 as emissive layer under the identical conditions. These results indicate that ABTPA unit could be a very promising candidate to replace TPA unit and find widely application in organic/polymeric optoelectronic materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3651–3661, 2009
Alkenyl‐functionalized precursors for renewable hydrogels design
Authors: Voepel Jens , Edlund Ulrica , Albertsson Ann‐Christine
Published: June 2009

A library of crosslinking chemistries for the hydrogel synthesis based on the hemicellulose acetylated galactoglucomannan (AcGGM) has been developed, demonstrated, and evaluated. A three‐step route was elaborated including (1) the carbonyldiimidazole activation of primary hydroxylated vinylic molecules such as acrylates, vinyl alcohols, and vinyl ethers, (2) the covalent coupling of the alkenyl precursors to the polysaccharide backbone hydroxyls, and (3) the radical crosslinking of pendant vinyl functionalities affording a hydrophilic network. Crosslinking strategies explored include redox initiation and photo initiation, with an effort to adapt the suggested synthesis routes to benign conditions. The different functionalization strategies were shown to influence the resulting gel's properties. Varying the crosslinking media was found to be a strong tool to tune the properties of the gels. Modifications were in all cases verified by means of NMR and FTIR, and the gels were characterized with respect to swelling capacity and rheological parameters. It was shown that by adjusting the synthesis parameters, the resulting properties of the AcGGM gels could be custom‐made for a given performance. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3595–3606, 2009
Anionic alternating copolymerization behavior of bifunctional six‐membered lactone and glycidyl phenyl ether
Authors: Uenishi Kazuya , Sudo Atsushi , Endo Takeshi
Published: June 2009

A copolymerization of 10‐methyl‐2H,8H‐benzo‐[1,2‐b:5,4‐b′]bipyran‐2,8‐dione (1) and glycidyl phenyl ether (GPE) was studied. 1 was a bislactone designed as a bifunctional analogue of 3,4‐dihydrocoumarin (DHCM), of which anionic 1:1 alternating copolymerization with GPE has been reported by us, previously. This alternating nature was inherited by the present copolymerization of 1 and GPE, leading to an intriguing copolymerization behavior in contrast to the ordinary statistical copolymerizations of monofunctional monomers and bifunctional monomers usually controlled by the proportional dependence of the crosslinking density on the monomer feed ratio: (1) When the feed ratio [GPE]0/[1]0 was 1, the two monomers underwent the 1:1 alternating copolymerization. In this case, 1 behaved as a monofunctional monomer, that is, only one of the two lactones in 1 participated in the copolymerization allowing the other lactone moiety to be introduced into the side chain almost quantitatively. (2) Increasing the feed ratio [GPE]0/[1]0 to larger than 4 allowed almost all of the lactone moieties to participate in the copolymerization system to give the corresponding networked polymers efficiently. The compositions of the copolymers [GPE unit]/[1‐derived acyclic ester unit] were always biased to smaller values than the feed ratios [GPE]0/[lactone moiety in 1]0 by the intrinsic 1:1 alternating nature of the copolymerization. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3662–3668, 2009
Raft polymerization of MMA in the presence of ferrocene: A new way to realize the rate enhancement
Authors: Chen Qifeng , Zhang Zhengbiao , Zhou Nianchen , Zhu Jian , Pan Qinmin , Zhu Xiulin
Published: June 2009

Ferrocene (Fe(Cp)2) was added to a thermal initiation of reversible addition‐fragmentation chain transfer (RAFT) polymerization of methyl methacrylate (MMA) with 2‐cyanoprop‐2‐yl 1‐dithionaphthalate (CPDN) as the RAFT agent at 115 °C. It was found that the polymerization was greatly promoted after the addition of Fe(Cp)2 while retaining the characteristics of a typical RAFT polymerization. It was proposed that the formation of a redox initiation system, in which the poly(methyl methacrylate) peroxide (PMMAP) generated in situ as the oxidizer and Fe(Cp)2 as the reducer, was possibly the reason for the interesting polymerization phenomenon. Such a redox initiation mechanism was further validated with ascorbic acid (VC) as the reducer instead of Fe(Cp)2. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3607–3615, 2009
Large‐compound vesicle‐encapsulated multiwalled carbon nanotubes: A unique route to nanotube composites
Authors: Zou Peng , Shi Gang‐Yin , Pan Cai‐Yuan
Published: June 2009

A simple and unique strategy for preparation of large‐compound vesicle (LCV)‐encapsulated multiwalled carbon nanotubes (MWCNTs) has been developed, and this involves dispersion of MWCNTs in H‐shaped copolymers solution in DMF and encapsulation of MWCNTs with LCVs formed from hydrolysis and polycondensation of Si(OCH3)3 groups in the amphiphilic H‐shaped copolymers, (PTMSPMA)2PEG(PTMSPMA)2. This unique noncovalent approach is nondestructive, and the original structure of MWCNTs remains in the resultant MWCNTs/LCVs nanocomposites. The morphologies of nanocomposites LCVs/MWCNTs are controlled by the chain length ratio (NPTMSPMA/NPEG) of PTMSPMA to PEG. For the H‐shaped copolymers with NPMSPMA/NPEG ≤ 1.7, they self‐assembled to form LCVs with dense cavities in the presence of MWCNTs in a mixture of DMF/H2O. When this ratio was more than 2.0, the large‐compound micelle‐wrapped MWCNTs were produced. This approach is potentially useful for preparation of MWCNTs encapsulated with various morphologies of polymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3669–3679, 2009
Scaling of the strain hardening modulus of glassy polymers with the flow stress
Authors: Robbins Mark O. , Hoy Robert S.
Published: June 2009

In a recent letter, Govaert et al. examined the relationship between strain hardening modulus Gr and flow stress σflow for five different glassy polymers. In each case, results for Gr at different strain rates or different temperatures were linearly related to the flow stress. They suggested that this linear relation was inconsistent with simulations. Data from previous publications and new results are presented to show that simulations also yield a linear relation between modulus and flow stress. Possible explanations for the change in the ratio of modulus to flow stress with temperature and strain rate are discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1406–1411, 2009
Crystallization studies on linear aliphatic n‐polyurethanes
Authors: Fernández C. E. , Bermudez M. , Versteegen R. M. , Meijer E. W. , Muller A. J. , Muñoz‐Guerra S.
Published: June 2009

A detailed crystallization study of the linear n‐polyurethane (n‐PUR) family for n ranging from 5 to 12 was carried out by DSC supported by polarizing optical microscopy. The study embraces crystallization of all the n‐PUR under both nonisothermal and isothermal conditions. The odd and even series of n‐PUR defined by the parity of the number of methylenes (n) contained in the polymer repeating unit are considered and separately analyzed. All the members of the two series showed a thermal behavior consistent with their chemical constitution. Isothermal crystallization data were analyzed by the kinetics Avrami approach which revealed that the “crystallizability” of n‐PUR increases steadily with the flexibility of the polyurethane chain. Melting and enthalpy temperatures of isothermally and nonisothermally crystallized n‐PUR were found to vary with n according to a zig‐zag plot characteristic of odd–even effect. Given the structural similitude of n‐PUR with (n + 2)‐nylons, results were referenced to those reported for this family of polyamides. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1368–1380, 2009
Key counter ion parameters governing polluted nafion membrane properties
Authors: Bas Corine , Reymond Laetitia , Danérol Anne‐sophie , Albérola Nicole D. , Rossinot Elisabeth , Flandin Lionel
Published: June 2009

Some properties of perfluorosulphonated ionomer membranes contaminated by a series of 10 counter ions were investigated by infrared spectroscopy (FTIR), thermogravimetric analysis coupled to mass spectroscopy (TG‐MS), and dynamic mechanical spectrometry (DMA). Distinctive parameters were extracted and regarded as a function of the cations' properties. An optimum interaction between sulfonate group and cation was found for cations with Lewis Acid Strength (LAS) in the 0.2–0.3 range. This critical value is found to be the Lewis Basic Strength (LBS‐) of the sulfonate anion in Nafion membrane. Thermal stability analyses also point out the influence of this cation parameter on the polymer degradation process. Cations with LAS values lower than LBS‐ improve the thermal stability of the side chains while cations with LAS values higher than LBS‐ enhance the thermal degradation. Moreover, the temperature of the modulus drop increases with the LAS of the counter ion. For cations with values lower 0.5, the transition is attributed to the glass relaxation of the polymer while for cations showing LAS values higher than 0.5, the loss of stiffness originates from the polymer thermal degradation process. The overview of the experimental data allows the definition of calibration curves as a function of the cations' LAS. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1381–1392, 2009
Studies on fracture behaviors of immiscible polypropylene/ethylene‐co‐vinyl acetate blends with multiwalled carbon nanotubes
Authors: Liu Li , Wang Yong , Li Yanli , Wu Jun , Xiang Fangming , Zhou Zuowan
Published: June 2009

Immiscible polypropylene/ethylene‐co‐vinyl acetate (PP/EVA) blends with two different compositions, one (PP/EVA = 80/20) exhibits the typical sea‐island morphology and the other (PP/EVA = 60/40) exhibits the cocontinuous morphology, were prepared with different contents of f‐MWCNTs. The fracture behaviors, including notched Izod impact fracture and single‐edge notched tensile (SENT) fracture, were comparatively studied to establish the role of f‐MWCNTs in influencing the fracture toughness of PP/EVA blends. Our results showed that, for PP/EVA (80/20) system, f‐MWCNTs do not induce the fracture behavior change apparently. However, for PP/EVA (60/40) system, the fracture toughness of the blend increases dramatically with the increasing of f‐MWCNTs content. More severe plastic deformation accompanied by the fibrillar structure formation was observed during the SENT test. Furthermore, SENT test shows that the significant improvement in fracture toughness of PP/EVA (60/40) with f‐MWCNTs is contributed to the simultaneous enhancement of crack initiation energy and crack propagation energy, but largely dominated by crack propagation stage. Further results based on crystalline structures and morphologies of the blends showed that a so‐called dual‐network structure of EVA and f‐MWCNTs forms in cocontinuous PP/EVA blends, which is thought to be the main reason for the largely improved fracture toughness of the sample. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1331–1344, 2009
Chiroptical aggregates from block copolymer bearing amino acid moieties in aqueous solution
Authors: Zhao Fabao , Liu Zhilei , Feng Liang , Sun Jianping , Hu Jiwen
Published: June 2009

Optically active poly(ethylene glycol) monomethyl ether‐b‐poly(methacryloyl‐L‐leucine methyl ester) (denoted as MPEG‐b‐PMALM) copolymers were prepared via atom transfer radical polymerization (ATRP), using bromine (Br) end‐capped poly(ethylene glycol) monomethyl ether (denoted as MPEG‐Br) as macroinitiator in the presence of CuBr/tris(2‐dimethylaminoethy1)amine (Me6TREN) as catalytic system. Broad range of morphologies, such as spherical, cylindrical, and vesicular micelles, which were prepared by initially dissolving prepared polymer in organic solvent at different concentration followed by addition various amount of water before dialysis against water to remove any added solvent, was observed by transmission electron microscope (TEM). More detailed chiroptical properties of the micelles/aggregates in aqueous solution were evaluated by circular dichroism (CD) spectroscopy as a function of micelles morphologies, polymer concentration, solvents employed, temperature, etc. The micellar solutions exhibit almost the same CD spectra regardless of its morphologies. The intensity of the CD spectra of the cylindrical micelles decreased in the molar ellipticities as the micellar concentration in water was increased. The Cotton effect was markedly changed when the solvent hydrophobicity was changed by addition of trifluoromethyl ethanol (TFME) to water. The intensity of the CD spectra decreased not too much within the temperature range from 20 °C to 90 °C, indicating good stability of the micelles upon temperature variation. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1345–1355, 2009
Copolymerization: A new tool to selectively induce poly(butylene naphthalate) crystal form
Authors: Soccio M. , Gazzano M. , Lotti N. , Finelli L. , Munari A.
Published: June 2009

Poly(butylene/diethylene naphthalate) copolymers (PBN‐PDEN) were synthesized in bulk according to the polycondensation procedure and examined by NMR, GPC, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and XRD. At room temperature they appeared as semicrystalline materials; the copolymerization caused a lowering in the Tg value, a decrement of Tm and of the crystallization rate. Pure α or β′ form was obtained at low and high DEN unit content, respectively; crystalline form transition never occurred in the solid state, analogously to PBN. After cooling from the melt, the pure α form was always evidenced in PBN‐PDEN10 and PBN‐PDEN20, whereas the pure β′ crystal phase develops in the copolymer containing 40 mol % DEN units, independently on the cooling rate. In the case of PBN‐PDEN30 a pure α or β′ form was obtained at low and high cooling rate, respectively. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1356–1367, 2009
Preparation and characterization of multiwalled carbon nanotube dispersions in polypropylene: Melt mixing versus solid‐state shear pulverization
Authors: Pujari Saswati , Ramanathan Thillaiyan , Kasimatis Kosmas , Masuda Jun'ichi , Andrews Rodney , Torkelson John M. , Brinson L. Catherine , Burghardt Wesley R.
Published: June 2009

Dispersions of multiwalled carbon nanotubes (MWNT) in polypropylene (PP) were prepared via conventional melt batch mixing and solid‐state shear pulverization. The properties and structure of each system were assessed via linear viscoelasticity, electrical conductivity, PP crystallization kinetics, dynamic mechanical analysis, scanning electron microscopy, and small angle X‐ray scattering. Increasing either the duration or the intensity of melt mixing leads to higher degrees of dispersion of MWNT in PP, although at the cost of substantial melt degradation of PP for long mixing times. Samples prepared by pulverization exhibit faster crystallization kinetics and higher mechanical stiffness than the melt blended samples, but in contrast show no measurable low frequency elastic plateau in melt rheology, and lower electrical conductivity than melt‐mixed samples. X‐ray scattering demonstrates that neither sample has uniform dispersion down to the single MWNT level. The results illustrate that subtle differences in the size and distribution of nanotube clusters lead to differences in the nanotube networks with strong impact on bulk properties. The results also highlight distinctions between conductive networks and load transfer networks and demonstrate that a complete and comparative picture of dispersion cannot be determined by simple indirect property measurements. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 1426–1436, 2009
Hospital admission for acute painful episode following methacholine challenge in an adolescent with sickle cell disease
Authors: Knight‐Perry Jessica E. , Field Joshua J. , DeBaun Michael R. , Stocks Janet , Kirkby Jane , Strunk Robert C.
Published: June 2009

Asthma is associated with increases in sickle cell disease (SCD)‐related morbidity and mortality. A thorough evaluation for asthma in children with SCD is important and may involve methacholine challenge (MCh). In this report, we present a 14‐year‐old male with SCD who was admitted for an acute painful episode following MCh. Pain events after MCh have not been previously reported in children with SCD. The risk–benefit ratio should be strongly considered prior to performance of MCh in this patient population, and all possible complications, including an acute painful episode, should be openly discussed with the parents and pediatric patient. Pediatr Pulmonol. 2009; 44:728–730. © 2009 Wiley‐Liss, Inc.
Relation of bone mineral density with clinical and laboratory parameters in pre‐pubertal children with cystic fibrosis
Authors: Cobanoglu Nazan , Atasoy Halil , Ozcelik Ugur , Yalcin Ebru , Dogru Deniz , Kiper Nural , Gocmen Ayhan
Published: June 2009

To study bone mineral density (BMD) of pre‐pubertal cystic fibrosis (CF) children, and its relation with clinical and laboratory parameters, we enrolled 16 CF (8 girls) (4–8 years), and 16 control children (8 girls) (4–8 years). After anthropometric measurements, BMD, serum calcium, phosphorus, total alkaline phosphatase (ALP), 25‐hydroxy vitamin D (25‐OHD), parathyroid hormone, osteocalcin, tumor necrosis factor (TNF)‐α, soluble TNF‐α receptor 2 (sTNFR2), and soluble IL‐2 receptor (sIL‐2R) levels, and urinary calcium and hydroxyproline excretions were assessed. Disease severity of CF patients was determined with Shwachman–Kulczycki clinical and Brasfield radiological scoring systems.

The mean Shwachman–Kulczycki and Brasfield scores of CF patients were indicating well‐controlled disease. The anthropometric measurements, mean BMD values, and serum calcium, phosphorus and parathyroid hormone levels were within normal range and similar in both groups. Serum osteocalcin levels were lower, and ALP and 25‐OHD levels were higher in CF. Although 24‐hr urinary calcium excretions was higher in CF patients, hydroxyproline excretions were similar in both groups. There was no difference between two groups for the serum levels of sIL‐2R, TNF‐α and sTNFR2. Children with low vertebral z‐scores had higher serum sIL‐2R levels in both groups, but the same relation could not be shown for TNF‐α and sTNFR2.

We may speculate that younger, healthier and well‐nourished patients with CF may have normal BMD, but the bone disease develop as patients get older because of the other contributing factors. Future well‐designed longitudinal studies with large cohorts might show a relation with BMD and cytokines in CF. Pediatr Pulmonol. 2009; 44:706–712. © 2009 Wiley‐Liss, Inc.
Ammonium Dinitramide (ADN)–Prilling, Coating, and Characterization
Authors: Heintz Thomas , Pontius Heike , Aniol Jasmin , Birke Christoph , Leisinger Karlfred , Reinhard Werner
Published: June 2009

Ammonium dinitramide (ADN) is the promising oxidizer, which is expected to be applied, e.g., in solid rocket propellants. The manufacturing of spherical ADN particles (the so‐called ADN‐Prills) with useful morphology and reproducible quality is realized by means of the emulsion crystallization process.
RFID tag readability issues with palletized loads of consumer goods
Authors: Singh J. , Olsen E. , Vorst K. , Tripp K.
Published: June 2009

Radio Frequency Identification (RFID) is an automatic identification technology, relying on storing and remotely retrieving data using devices called RFID tags. This technology is being used in enterprise supply chain management‐related applications to improve the efficiency of inventory tracking and management. However, this technology has not been able to realize its promised potential because of several factors, such as lack of congruous worldwide standards, privacy issues and less than perfect read rates in supply chain applications. This research aimed to evaluate the readability issues commonly faced by tagged cases of palletized consumer products. The variables studied in this research were product‐package type, tag type, tag location on cases, pallet pattern and forklift speed through a RFID portal representative of a dock door in a warehouse. To determine which variables were the most significant, a binary logistic regression was run. The number of tags read was inputted for the number of events and total number of products per pallet as the number of trials. The variables product content, pallet pattern, and speed, and all interactions were then included in the model. It was observed that readability greatly varies for different product‐package systems, with paper towels producing near‐perfect reads, followed by bottled water and carbonated soda cans. The slower the forklift truck speed, the better the readability across the board, and the best pallet patterns were dependent on the product‐package type. For bottled water, the best pallet pattern was column, and for carbonated soda, the interlocking pattern. Copyright © 2009 John Wiley & Sons, Ltd.
A method to measure the total scattering cross section and effective beam gas path length in a low‐vacuum SEM
Authors: Rattenberger J. , Wagner J. , Schröttner H. , Mitsche S. , Zankel A.
Published: June 2009

A method is presented to determine the total scattering cross section of imaging gases used in low‐vacuum scanning electron microscopy or environmental scanning electron microscopy. Experimental results are presented for water vapor, nitrogen gas and ambient air for primary beam electron energies between 5 and 30 keV. The measured results are compared and discussed with calculated values. This method allows the effective beam gas path length (BGPL) to be determined. The variations of the effective BGPL with varying chamber pressure are presented. SCANNING 31: 107–113, 2009. © 2009 Wiley Periodicals, Inc.
Toward the Identification of a “Renopoietic System”?
Authors: Romagnani Paola
Published: June 2009

Chronic kidney disease is a leading cause of mortality and morbidity in Western countries and is estimated to affect 11% of the adult population. The possibility of treatment of chronic kidney disease has been severely impaired by our poor knowledge of the regenerative properties of the kidney. Recent results obtained in humans, together with genetic tagging experiments performed in rodents, demonstrated that the epithelial components of the cortical nephron share a unique progenitor, which can generate podocytes as well as tubular cells. Accordingly, lineage tracing experiments demonstrated that bone marrow-derived interstitial or papillary cells are not involved in the repair of injured adult renal epithelium. In addition, assessment of the markers CD24 and CD133 in adult human kidney as well as genetic tagging in rodents allowed us to identify a hierarchical population of renal progenitors arranged in a precise sequence within Bowman's capsule. The results of all of these studies suggest that the kidney contains a “renopoietic system,” with a progenitor localized at the urinary pole of Bowman's capsule, from where it can initiate the replacement and regeneration of glomerular, as well as tubular, epithelial cells. Knowledge of renal progenitor cell biology may enable a better comprehension of the mechanisms of renal repair as well as more effective targeted therapies for acute and chronic kidney diseases.

Disclosure of potential conflicts of interest is found at the end of this article.
Pulse shaping for cognitive ultra‐wideband communications
Authors: Wu Xuan‐li , Sha Xue‐jun , Li Cheng , Zhang Nai‐tong
Published: June 2009

Cognitive ultra‐wideband (C‐UWB) systems have recently received much attention because the huge bandwidth of ultra‐wideband (UWB) systems can better exploit the advantages of cognitive radio (CR) systems. Dynamic spectrum access (DSA) is a key technique in CR systems to implement dynamic spectrum change and can be easily implemented by changing the transmitted pulse shape in a C‐UWB communication system. In this paper, we propose an orthogonal expansion based pulse shaping method to implement DSA and to compensate for antenna distortion, which uses the orthogonal Hermite functions as the orthogonal basis. In order to eliminate the direct current (DC) component existing in even orthogonal Hermite functions and to reduce the computational complexity, two modified methods and a simplification procedure are also proposed. Our results indicate that the proposed orthogonal expansion based pulse shaping methods have a much lower computational complexity than the semi‐definite programming (SDP) method, while achieving a high power efficiency. Furthermore, we demonstrate that the distortion caused by the antenna effects can also be compensated during the pulse shaping process and a better signal‐to‐noise ratio (SNR) can thus be achieved. Therefore, the proposed method is very suitable for practical application in C‐UWB communications, in which the spectrum environment changes rapidly. Copyright © 2009 John Wiley & Sons, Ltd.
Modelling and control of variable speed wind turbines for power system studies
Authors: Michalke Gabriele , Hansen Anca D.
Published: June 2009

Modern wind turbines are predominantly variable speed wind turbines with power electronic interface. Emphasis in this paper is therefore on the modelling and control issues of these wind turbine concepts and especially on their impact on the power system. The models and control are developed and implemented in the power system simulation tool DIgSILENT. Important issues like the fault ride‐through and grid support capabilities of these wind turbine concepts are addressed. The paper reveals that advanced control of variable speed wind turbines can improve power system stability. Finally, it will be shown in the paper that wind parks consisting of variable speed wind turbines can help nearby connected fixed speed wind turbines to ride‐through grid faults. Copyright © 2009 John Wiley & Sons, Ltd.
A stochastic model for the simulation of wind turbine blades in static stall
Authors: Bertagnolio Franck , Rasmussen Flemming , Sørensen Niels N. , Johansen Jeppe , Madsen Helge Aa.
Published: June 2009

The aim of this work is to improve aeroelastic simulation codes by accounting for the unsteady aerodynamic forces that a blade experiences in static stall. A model based on a spectral representation of the aerodynamic lift force is defined. The drag and pitching moment are derived using a conditional simulation technique for stochastic processes. The input data for the model can be collected either from measurements or from numerical results from a Computational Fluid Dynamics code for airfoil sections at constant angles of attack. An analysis of such data is provided, which helps to determine the characteristics of stall. The model is applied to wind turbine rotor cases, including the stand still condition, and results are compared to experimental data. Copyright © 2009 John Wiley & Sons, Ltd.
Coenzyme Q10 is decreased in fibroblasts of patients with methylmalonic aciduria but not in mevalonic aciduria
Authors: Haas D. , Niklowitz P. , Hörster F. , Baumgartner E. R. , Prasad C. , Rodenburg R. J. , Hoffmann G. F. , Menke T. , Okun J. G.
Published: June 2009

The content of coenzyme Q10 (CoQ10) was examined in skin fibroblasts of 10 patients with mevalonic aciduria (MVA) and of 22 patients with methylmalonic aciduria (MMA). Patients with these inborn errors of metabolism are thought to be at risk for CoQ10 depletion either by direct inhibition of the proximal pathway of CoQ10 synthesis (MVA) or indirectly by inhibition of mitochondrial energy metabolism (MMA). We demonstrated that CoQ10 concentrations were not significantly different from controls in MVA patients, suggesting that there may be upregulatory effects. On the other hand the CoQ10 content in fibroblasts of patients with MMA was significantly reduced.
Black hip, fracture neck of femur and scoliosis: A case of ochronosis
Authors: Zacharia B. , Chundarathil J. , Ramakrishnan V. , Krishnankutty R. M. , Veluthedath R. , Puthezhath K. , Varughese I.
Published: June 2009

Background: Ochronosis is a very rare disorder with an incidence of 2 to 5 per million live births. It is a genetic disorder with autosomal recessive inheritance. It is characterized by dark brown pigmentation of cartilage, capsules of joints and other soft tissues. Ochronosis usually presents as ochronotic arthropathy and spondylosis. Purpose: This article describes a very rare presentation of scoliosis and fracture of the neck of the femur in a patient with ochronosis. Methods: A 65‐year‐old woman with left‐sided scoliosis presented to us following a fall with fracture of the neck of the femur on the left side. Radiological examination and biochemical study of urine were consistent with ochronosis. Procedure and results: We have treated the patient by excision arthroplasty. Conclusion: We report a case of scoliosis, fracture of the neck of the femur and ochronosis occurring together in a patient.
Shape-Controlled Synthesis of ZnS Nanostructures: A Simple and Rapid Method for One-Dimensional Materials by Plasma
Authors: Peng Hu , Liuyang Bai , Lingjie Yu , Jinlin Li , Fangli Yuan , Yunfa Chen
Published: June 2009

In this paper, ZnS one-dimensional (1D) nanostructures including tetrapods, nanorods, nanobelts, and nanoslices were selectively synthesized by using RF thermal plasma in a wall-free way. The feeding rate and the cooling flow rate were the critical experimental parameters for defining the morphology of the final products. The detailed structures of synthesized ZnS nanostructures were studied through transmission electron microscope, X-ray diffraction, and high-resolution transmission electron microscope. A collision-controlled growth mechanism was proposed to explain the growth process that occurred exclusively in the gas current by a flowing way, and the whole process was completed in several seconds. In conclusion, the present synthetic route provides a facile way to synthesize ZnS and other hexagonal-structured 1D nanostructures in a rapid and scalable way.
Water-Driven Assembly of Laser Ablation-Induced Au Condensates as Mesomorphic Nano- and Micro-Tubes
Authors: Huang Chang-Ning , Chen Shuei-Yuan , Zheng Yuyuan , Shen Pouyan
Published: June 2009

Reddish Au condensates, predominant atom clusters and minor amount of multiply twinned particles and fcc nanoparticles with internal compressive stress, were produced by pulsed laser ablation on gold target in de-ionized water under a very high power density. Such condensates were self-assembled as lamellae and then nano- to micro-diameter tubes with multiple walls when aged at room temperature in water for up to 40 days. The nano- and micro-tubes have a lamellar- and relaxed fcc-type wall, respectively, both following partial epitaxial relationship with the co-existing multiply twinned nanoparticles. The entangled tubes, being mesomorphic with a large extent of bifurcation, flexibility, opaqueness, and surface-enhanced Raman scattering, may have potential encapsulated and catalytic/label applications in biomedical systems.
Preparation and Properties of Phosphate Surfactants Containing Ether and Hydroxy Groups
Authors: Osanai Shuichi , Yamada Go , Hidano Ruri , Beppu Koji , Namiwa Kimiyoshi
Published: June 2009

Phosphate surfactants containing ether and hydroxyl groups were prepared by a simple reaction between the corresponding epoxide and the diethyl phosphate. The relationships between the structure and colloidal properties were evaluated in terms of the critical micelle concentration (CMC), γCMC, foaming ability, and water absorbing and holding abilities. Based on these results, it was concluded that the ether and hydroxy groups synergistically worked together to decrease the CMC and increase the foaming ability. The degree of neutralization remarkably affected the colloidal properties. The highly neutralized states showed a more positive effect on water holding power but an opposite effect on the foaming ability.
Dietary Lipid Level Induced Antioxidant Response in Manchurian Trout, Brachymystax lenok (Pallas) Larvae
Authors: Zhang Hui , Mu Zhenbo , Xu LiangMei , Xu Gefeng , Liu Min , Shan Anshan
Published: June 2009

This study was designed to determine the nutritional lipid requirement of Manchurian trout and to investigate the effects of lipid concentrations on the antioxidant status in larvae with experimental diets with different lipid levels. Oxidative stress differences between different organs and tissues were also assessed. Manchurian trout larvae were fed for 35 days and, during that period, growth and survival, the activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and content of malondialdehyde (MDA) in viscera, muscle, gill and brain of four diets, lipid levels from 15 to 30%, and control treatment were measured. Growth rates were similar, but survival was low, between high and low dietary lipid levels. SOD activity was stimulated in viscera, muscle and brain in high lipid diets, but reduced in gills with increased lipid content. SOD was kept lower in the control group. GPX activity was inhibited in viscera and stimulated in gill, muscle and brain. CAT activities were enhanced by all treatments and showed the lowest values in the control. Lipid peroxidation of the diet was promoted in all organs, excluding the gill which showed no regular pattern. MDA content increased with increased dietary lipid levels in viscera, muscle and brain. Our results indicate that the most appropriate lipid requirement is probably 20–25% and a higher dietary level of lipids might induce oxidative stress in Manchurian trout larvae. The brain and gill were probably the most sensitive organs to oxidative damage.
Quantitative Analysis of Dairy Phospholipids by 31P NMR
Authors: MacKenzie Andrew , Vyssotski Mikhail , Nekrasov Eduard
Published: June 2009

31P NMR analysis of samples prepared in a sodium cholate detergent system was assessed as a method for the quantitative measurement of dairy phospholipids. Major phospholipid (PL) classes measured included: phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidylinositol (PI), sphingomyelin (SM) and dihydrosphingomyelin (DHSM). The 31P NMR method was validated by comparison with a quantitative two‐dimensional thin‐layer chromatography (2D‐TLC) technique. The 2D‐TLC system was more sensitive, able to detect some minor compounds not observed by 31P NMR. However, 31P NMR is more suited to routine analysis, with sample analysis taking 36 min. The method was also more versatile and sample analysis was possible on high phospholipid containing materials without prior lipid extraction (e.g. buttermilk protein concentrate, beta serum liquid).
Holocene vegetation history in Romanian Subcarpathians
Authors: Tantau Ioan , Reille Maurice , de Beaulieu Jacques-Louis , Farcas Sorina , Brewer Simon
Published: June 2009

Pollen analysis from a peat core 7.0 m in length, taken from a bog near Bisoca, in a mid-altitude area of the Buzăului Subcarpathian mountains, is used to reconstruct the postglacial vegetation history of the region. The vegetation record, which is supported by twelve 14C dates, starts at the end of the Late Glacial period. At the Late Glacial/Holocene transition, open vegetation was replaced by forest, suggesting a fast response to climatic warming. The Holocene began with the expansion of Betula, Pinus and Ulmus, followed, after 11,000 cal yr BP, by Fraxinus, Quercus, Tilia and Picea. The rapid expansion of these taxa may be due to their existence in the area during the Late Glacial period. At ca. 9200 cal yr BP, Corylus expanded, reaching a maximum after 7600 cal yr BP. The establishment of Carpinus occurred at ca. 7200 cal yr BP, with a maximum at ca. 5700 cal yr BP. Fagus pollen is regularly recorded after 7800 cal yr BP and became dominant at ca. 2000 cal yr BP. The first indications of human activities appear around 3800 cal yr BP.
The medical history of South Georgia
Authors: Keys Jennifer , Guly Henry
Published: June 2009

The first landing on South Georgia was made in 1775. Sealing expeditions arrived soon afterwards, and during the 18th, 19th and 20th centuries men plundered the beaches and seas surrounding the island for seals and whales. Sealing and whaling ceased in the 1960s, when declining whale numbers and the increasing use of other forms of oil made the industry uneconomical. Although an isolated island with a small population and a severe climate, South Georgia has a rich history. Its medical history has not been previously studied. This paper aims to look at some aspects of the medical history of the island, from early expeditions of discovery, through to the 20th century whaling industry. Surviving whalers and whaling doctors were interviewed. Published material with any relevance to South Georgia, including academic texts and personal memoirs, were searched for details of hospitals, doctors and medical events on the island. Documents archived in South Georgia, the Falkland Islands and the United Kingdom revealed much useful information, and occasional documents came to light from other sources. Aspects of the provision of medical services over two centuries from 1775 to the beginning of the 1960s are described. Morbidity and mortality are summarised and discussed, as are differences between medical care in South Georgia and standard care.
Food security in Igloolik, Nunavut: an exploratory study
Authors: Ford James D. , Berrang-Ford Lea
Published: June 2009

This paper reports on an exploratory analysis examining the prevalence of food (in)security in the Inuit community of Igloolik, Nunavut, identifying high risk groups, and characterising conditions facilitating and constraining food security. A stratified cross-sectional food survey was administered to 50 Inuit community members in July 2007. 64% of the participants surveyed experienced some degree of food insecurity in the past year (July 2006–July 2007). Food insecurity among the sample population greatly exceeds the Canadian average. This is cause for concern given the negative physical and mental health impacts that have been documented for low nutritional status. The prevalence and severity of food insecurity differed among participants; females and those obtaining most of their food from the store were at highest risk of food insecurity. Consumption of traditional foods was significantly associated with increased food security. The study supports the need for further research to investigate key trends highlighted by the sample. Preliminary identification of potential trends contributes towards the goal of identifying entry points for policy aimed at strengthening northern Inuit food systems.
The first International Polar Year (1882–1883): French measurements of carbon dioxide concentrations in the atmosphere at Bahia Orange, Hoste Island, Tierra del Fuego
Authors: Baker F.W.G.
Published: June 2009

During the first International Polar Year (1882–1883) the French expedition to Bahia Orange, Hoste Island, Tierra del Fuego carried out a series of 39 measurements of concentrations of carbon dioxide in the atmosphere. These were supplemented by 6 measurements during the return voyage to Cherbourg. In addition 20 similar measurements were made at 4 stations in the northern hemisphere and 17 at 3 stations in the southern hemisphere that were participating in the transit of Venus observations.
Surveillance for antimicrobial resistant organisms: potential sources and magnitude of bias
Authors: REMPEL O. R. , LAUPLAND K. B.
Published: June 2009

Surveillance has been recognized as a fundamental component in the control of antimicrobial- resistant infections. Although surveillance data have been widely published and utilized by researchers and decision makers, little attention has been paid to assessment of their validity. We conducted this review in order to identify and explore potential types and magnitude of bias that may influence the validity or interpretation of surveillance data. Six main potential areas were assessed. These included bias related to use of inadequate or inappropriate (1) denominator data, (2) case definitions, and (3) case ascertainment; (4) sampling bias; (5) failure to deal with multiple occurrences, and (6) those related to laboratory practice and procedures. The magnitude of these biases varied considerably for the above areas within different study populations. There are a number of potential biases that should be considered in the methodological design and interpretation of antimicrobial-resistant organism surveillance.
Beratung von pflegenden Angehörigen demenzkranker Patienten
Authors: Poll Eva , Gauggel Siegfried
Published: June 2009

Viele Patienten mit einer demenziellen Erkrankung (z. B. Morbus Alzheimer) werden von Angehörigen zuhause gepflegt. Zahlreiche Studien zeigen, dass die Pflege mit erheblichen körperlichen und psychischen Belastungen, aber auch mit positiven Erfahrungen verbunden sein kann. In diesem Beitrag geben wir einen kurzen Überblick über die mit der Pflege von Demenzkranken verbunden psychosozialen Belastungen und weisen auf die spezifischen Bedürfnisse der Pflegenden hin. Anschließend beschreiben wir therapeutische Interventionen zur Reduktion der Pflegebelastung und gehen auf deren Effektivität ein. Empfehlungen zur Angehörigenberatung beenden den Beitrag.
Die Reservekapazität des Gehirns beeinflusst die kognitive Funktion im Alter: Motivationale, kognitive und körperliche Facetten
Authors: Forstmeier Simon , Maercker Andreas
Published: June 2009

Die Reservekapazität des Gehirns ist seine Fähigkeit, neuropathologische Veränderungen so zu tolerieren, dass ihre klinische Manifestation hinausgezögert wird. Diese Studie untersucht, inwiefern frühere motivationale („motivationale Reserve“), kognitive und körperliche Fähigkeiten bzw. Aktivitäten unabhängige Prädiktoren einer leichten kognitiven Beeinträchtigung im Alter sind. Eine Stichprobe von 147 nicht-dementen Personen zwischen 60 und 94 Jahren absolvierte kognitive Tests und Fragebogen zur Berufsbiographie sowie früheren körperlichen Aktivitäten. Frühere motivationale und kognitive Fähigkeiten wurden auf der Basis des Hauptberufs unter Anwendung der Datenbank des Occupational Information Networks (O*NET) geschätzt. Die früheren motivationalen Fähigkeiten und die kristallisierte Intelligenz sagten ein reduziertes Risiko einer leichten kognitiven Beeinträchtigung voraus, nicht aber frühere körperliche Aktivitäten. Die Ergebnisse legen nahe, dass insbesondere die motivationale Reservekapazität als protektiver Faktor gegen kognitive Beeinträchtigung im Alter wirkt.