bluuebunny/crossref_metadata_2025 huggingface dataset:
Constructing a cognition map of alternative fuel vehicles using the DEMATEL method
Authors: Lin Cheng‐Wei , Chen Sheng‐Hung , Tzeng Gwo‐Hshiung
Published: January 2010

Environmental protection has taken serious notice of global warming. The Intergovernmental Panel on Climate Change (IPCC) has proved that CO2 is one of the factors for global warming. Furthermore, the majority of this emission comes from the vehicles using petroleum fuels. For this reason, alternative fuels become a very popular issue. There are many automakers and researchers endeavoring to develop alternative fuel vehicles (AFVs). There already have been many types of alternative fuels used in vehicles, such as electric vehicles (EVs), hybrid electric vehicles (HEVs), fuel cell (hydrogen) vehicles, natural gas vehicles (CNG), methanol vehicles, ethanol vehicles, and bio‐diesel vehicles, etc. Different types of the alternative fuels have different characteristics to which attention should be paid. It is difficult for users to identify which one is the best choice for them to use. This problem concerns the characteristics of each alternative fuel. A lot of criteria and aspects related to the alternative fuels should be considered at the same time. In this study, we try to apply the Decision‐Making Trial and Evaluation Laboratory (DEMATEL) method to deal with the importance and causal relationships among the evaluation factors of AFVs. Results show the top three critical evaluation criteria are ‘new car cost’, ‘cruising range’, and ‘fuel efficiency’; ‘air pollution’ is the key cause factor influencing others; and ‘cruising range’ is the key effect factor influenced by others. It is no accident that cost is the most critical factor for users. Consequently, it is suggested to automakers and researchers to carefully analyze the characteristics of each alternative fuel. Fuel efficiency is not only focused on by users, but also it will affect the cruising range. Air pollution is what users care about, so even zero‐emission vehicles (ZEVs), which cost more but have lower emission and higher fuel efficiency, could be accepted. There seems to be no perfect AFV, but to endeavor on ZEVs will reduce some disadvantages. Copyright © 2010 John Wiley & Sons, Ltd.
HADS, a goal programming‐based humanitarian aid distribution system
Authors: Vitoriano B. , Ortuño T. , Tirado G.
Published: January 2010

In recent years, natural and human‐made disasters have been affecting increasing numbers of people throughout the world. Organizations and budgets for emergency and humanitarian aid have experienced an important growth, and efficiency in disaster management becomes crucial. There is a lack of specific tools devoted to logistics of this special kind of interventions in developing countries, demanded by the organizations. A decision support system for logistic operations currently in development is presented, focusing on the transport problem to distribute humanitarian aid to the population affected by a disaster in a developing country. Copyright © 2010 John Wiley & Sons, Ltd.
Vaccination as a Therapeutic Approach to Alzheimer's Disease
Authors: Wisniewski Thomas , Boutajangout Allal
Published: January 2010

Alzheimer's disease is the most common cause of dementia worldwide. Alzheimer's disease is a member of a broad range of neurodegenerative diseases characterized pathologically by the conformational change of a normal protein into a pathological conformer with a high β‐sheet content that renders it neurotoxic. In the case of Alzheimer's disease, the normal soluble amyloid β peptide is converted into oligomeric/fibrillar amyloid β. The oligomeric forms of amyloid β have been hypothesized to be the most toxic, whereas fibrillar amyloid β becomes deposited as amyloid plaques and congophilic angiopathy, which both serve as neuropathological markers of the disease. In addition, the accumulation of abnormally phosphorylated tau as soluble toxic oligomers and as neurofibrillary tangles is a critical part of the pathology. Numerous therapeutic interventions are under investigation to prevent and treat Alzheimer's disease. Among the most exciting and advanced of these approaches is vaccination. Immunomodulation is being tried for a range of neurodegenerative disorders, with great success being reported in most model animal trials; however, the much more limited human data have shown more modest clinical success so far, with encephalitis occurring in a minority of patients treated with active immunization. The immunomodulatory approaches for neurodegenerative diseases involve targeting a self‐protein, albeit in an abnormal conformation; hence, effective enhanced clearance of the disease‐associated conformer has to be balanced with the potential risk of stimulating excessive toxic inflammation within the central nervous system. The design of future immunomodulatory approaches that are more focused is dependent on addressing a number of questions, including when is the best time to start immunization, what are the most appropriate targets for vaccination, and is amyloid central to the pathogenesis of Alzheimer's disease or is it critical to target tau‐related pathology also. In this review, we discuss the past experience with vaccination for Alzheimer's disease and the development of possible future strategies that target both amyloid β—related and tau‐related pathologies. Mt Sinai J Med 77:17&–31, 2010. © 2010 Mount Sinai School of Medicine
Transgenic Mouse Models of Alzheimer's Disease
Authors: Elder Gregory A. , Gama Sosa Miguel A. , De Gasperi Rita
Published: January 2010

Alzheimer's disease is the most common cause of senile dementia in the United States and Europe. At present, there is no effective treatment. Given the disease's prevalence and poor prognosis, the development of animal models has been a high research priority. Transgenic modeling has been pursued on the basis of the amyloid hypothesis and has taken advantage of mutations in the amyloid precursor protein and the presenilins that cause familial forms of Alzheimer's disease. Modeling has been most aggressively pursued in mice, for which the techniques of genetic modification are well developed. Transgenic mouse models now exist that mimic a range of Alzheimer's disease–related pathologies. Although none of the models fully replicates the human disease, the models have contributed significant insights into the pathophysiology of β‐amyloid toxicity, particularly with respect to the effects of different β‐amyloid species and the possible pathogenic role of β‐amyloid oligomers. They have also been widely used in the preclinical testing of potential therapeutic modalities and have played a pivotal role in the development of immunotherapies for Alzheimer's disease that are currently in clinical trials. These models will, without a doubt, continue to play central roles in preclinical testing and be used as tools for developing insights into the biological basis of Alzheimer's disease. Mt Sinai J Med 77:69&–81, 2010. © 2010 Mount Sinai School of Medicine
Cell “Self‐Eating” (Autophagy) Mechanism in Alzheimer's Disease
Authors: Funderburk Sarah F. , Marcellino Bridget K. , Yue Zhenyu
Published: January 2010

The autophagy pathway is the major degradation pathway of the cell for long‐lived proteins and organelles. Dysfunction of autophagy has been linked to several neurodegenerative disorders that are associated with an accumulation of misfolded protein aggregates. Alzheimer's disease, the most common neurodegenerative disorder, is characterized by 2 aggregate forms, tau tangles and amyloid‐β plaques. Autophagy has been linked to Alzheimer's disease pathogenesis through its merger with the endosomal‐lysosomal system, which has been shown to play a role in the formation of the latter amyloid‐β plaques. However, the precise role of autophagy in Alzheimer's disease pathogenesis is still under contention. One hypothesis is that aberrant autophagy induction results in an accumulation of autophagic vacuoles containing amyloid‐β and the components necessary for its generation, whereas other evidence points to impaired autophagic clearance or even an overall reduction in autophagic activity playing a role in Alzheimer's disease pathogenesis. In this review, we discuss the current evidence linking autophagy to Alzheimer's disease as well as the uncertainty over the exact role and level of autophagic regulation in the pathogenic mechanism of Alzheimer's disease. Mt Sinai J Med 77:59&–68, 2010. © 2010 Mount Sinai School of Medicine
Repeatability of DTI‐based skeletal muscle fiber tracking
Authors: Heemskerk Anneriet M. , Sinha Tuhin K. , Wilson Kevin J. , Ding Zhaohua , Damon Bruce M.
Published: January 2010

Diffusion tensor imaging (DTI)‐based muscle fiber tracking enables the measurement of muscle architectural parameters, such as pennation angle (θ) and fiber tract length (Lft), throughout the entire muscle. Little is known, however, about the repeatability of either the muscle architectural measures or the underlying diffusion measures. Therefore, the goal of this study was to investigate the repeatability of DTI fiber tracking‐based measurements and θ and Lft. Four DTI acquisitions were performed on two days that allowed for between acquisition, within day, and between day analyses. The eigenvalues and fractional anisotropy were calculated at the maximum cross‐sectional area of, and fiber tracking was performed in, the tibialis anterior muscle of nine healthy subjects. The between acquisitions condition had the highest repeatability for the DTI indices and the architectural parameters. The overall inter class correlation coefficients (ICC's) were greater than 0.6 for both θ and Lft and the repeatability coefficients were θ < 10.2° and Lft < 50 mm. In conclusion, under the experimental and data analysis conditions used, the repeatability of the diffusion measures is very good and repeatability of the architectural measurements is acceptable. Therefore, this study demonstrates the feasibility for longitudinal studies of alterations in muscle architecture using DTI‐based fiber tracking, under similar noise conditions and with similar diffusion characteristics. Copyright © 2010 John Wiley & Sons, Ltd.
Characterizing human adipose tissue lipids by long echo time 1H‐MRS in vivo at 1.5 Tesla: validation by gas chromatography
Authors: Lundbom Jesper , Hakkarainen Antti , Fielding Barbara , Söderlund Sanni , Westerbacka Jukka , Taskinen Marja‐Riitta , Lundbom Nina
Published: January 2010

The aim of this study was to investigate the use of 1H‐MRS with various echo times to characterize subcutaneous human adipose tissue (SAT) triglyceride composition and to validate the findings with fatty acid (FA) analysis of SAT biopsies by gas chromatography (GC). 1H‐MRS spectra were acquired with a 1.5 Tesla clinical imager from the SAT of 17 healthy volunteers, with 10 undergoing SAT biopsy. Spectra were localized with PRESS and a series of echo times; 30,50,80,135,200,300 and 540 ms were acquired with TR = 3000 ms. Prior knowledge from phantom measurements was used to construct AMARES fitting models for the lipid spectra. SAT FA composition were compared with serum lipid levels and subject characteristics in 17 subjects.

Long TE (135,200 ms) spectra corresponded better with the GC data than short TE (30,50 ms) spectra. TE = 135 ms was found optimal for determining diallylic content (R = 0.952, p < 0.001) and TE = 200 ms was optimal for determining olefinic content (R = 0.800, p < 0.01). The improved performance of long TE spectra is a result of an improved baseline and better peak separation, due to J‐modulation and suppression of water. The peak position of the diallylic resonance correlated with the average double bond content of polyunsatured fatty acids with R = 0.899 (p < 0.005). The apparent T2 of the methylene resonance displayed relatively small inter‐individual variation, 88.1 ± 1.1 ms (mean ± SD). The outer methyl triplet line of ω‐3 PUFA at 1.08 ppm could be readily detected and quantitated from spectra obtained at TE = 540. The ω‐3 resonance correlated with the ω‐3 content determined by GC with R = 0.737 (p < 0.05, n = 8). Age correlated significantly with SAT diallylic content (R = 0.569, p = 0.017, n = 17), but serum lipid levels showed no apparent relation to SAT FA composition. We conclude that long TE 1H‐MRS provides a robust non‐invasive method for characterizing adipose tissue triglycerides in vivo. Copyright © 2010 John Wiley & Sons, Ltd.
Dental health of 19th century migrant mineworkers from Kimberley, South Africa
Authors: van der Merwe A. E. , Steyn M. , Maat G. J. R.
Published: January 2010

Dental health may deteriorate in populations exposed to economic growth as a result of easier access to refined carbohydrates and sugars. Such changes affected migrant labourers working in Kimberley, South Africa, during the late 19th century. A rescue excavation salvaged several skeletons from pauper's graves dating from this period, and the purpose of the study was to assess their dental health to determine whether it concurs with historical statements suggesting that the skeletal population sample being investigated was migrant labourers with limited access to a healthy diet. According to historic sources their diets mainly consisted of ground carbohydrates and occasional meat.

The permanent dentition of 79 males and 13 females (majority between 20 and 49 years of age) were examined. Carious lesions were observed in 57% of males and 46.2% of females with an average of 2.7 and 3.8 carious teeth per mouth. The anterior teeth were significantly less affected than the posterior teeth. Periodontal granulomata (‘abscesses’) were observed in 17.7% of males and 15.4% of females, and periodontal disease affected 40% of those investigated. Antemortem tooth loss (AMTL) was recorded in 29% (N = 27) of the sample with an average of 3.5 teeth lost per mouth.

It was concluded that the prevalence of dental caries, periapical granulomata and periodontal disease as well as the pattern of AMTL observed concurs with dietary descriptions for paupers in historical documents. The relatively low prevalence of carious lesions can be ascribed to the limited time migrant labourers spent in Kimberley and the labour restrictions they had to comply with during their stay in the compounds. Copyright © 2010 John Wiley & Sons, Ltd.
Maternal serum human placental growth hormone at 11 to 13 weeks in trisomy 21 and trisomy 18 pregnancies
Authors: Sifakis Stavros , Akolekar Ranjit , Syngelaki Argyro , De Cruz Jader , Nicolaides Kypros H
Published: January 2010

Objective

To investigate the maternal serum concentration of human placental growth hormone (hPGH) in trisomy 21 and trisomy 18 pregnancies at 11 to 13 weeks of gestation and to examine the possible association between fetal nuchal translucency (NT) thickness and maternal serum free beta‐human chorionic gonadotrophin (β‐hCG) and pregnancy‐associated plasma protein‐A (PAPP‐A).

Methods

The maternal serum concentration of hPGH at 11 to 13 weeks was measured in a case–control study from 28 pregnancies with fetal trisomy 21, 28 with trisomy 18 and 112 pregnancies with euploid fetuses. The median hPGH multiple of the median (MoM) in trisomy 21 and trisomy 18 pregnancies were compared with euploid pregnancies.

Results

Serum hPGH was significantly lower in trisomy 21 (0.93 MoM) and trisomy 18 (0.62 MoM) compared to euploid pregnancies (1.02 MoM). There was a significant association between serum hPGH and PAPP‐A in both the euploid (r = 0.258, p = 0.006) and trisomy 21 pregnancies (r = 0.410, p = 0.030) but not in trisomy 18 pregnancies (p = 0.445).

Conclusion

In the first trimester, serum hPGH in trisomy 21 and trisomy 18 pregnancies is reduced. This is the opposite of findings in previous studies reporting that in the second trimester, trisomy 21 and 18 pregnancies have increased hPGH. Copyright © 2010 John Wiley & Sons, Ltd.
Influence of experience, case load, and stage distribution on outcome of endoscopic laser surgery for TTTS—a review
Authors: Ahmed Shair , Luks Francois I. , O'Brien Barbara M. , Muratore Christopher S. , Carr Stephen R.
Published: January 2010

Objective

Survival (≥1 twin) after laser surgery for patients with twin‐to‐twin transfusion syndrome (TTTS) ranges from 65 to 93%. However, most studies are noncontrolled and retrospective, and have included a limited number of patients. The aim of this study was to perform a systematic review of outcomes after laser surgery in patients with TTTS.

Methods

We conducted database and manual searches of reference lists and pertinent journals published between 1995 and 2009 that report outcomes of laser surgery in patients with TTTS. Two authors performed the search independently of each other. There exist only two randomized controlled trials, each with fewer than 80 patients having undergone laser surgery. Uncontrolled and retrospective series were therefore considered as well. Studies had to report sufficient information on inclusive dates, stage distribution, overall neonatal survival, and neonatal survival of at least one twin. Of the 486 studies identified, we considered 19 studies.

Results

For each series, 95% confidence intervals (CI) were calculated. Survival was plotted against the date of publication, number of patients/series, gestational age at delivery, and proportion of advanced cases. Univariate analysis was performed to detect significant differences. Our meta‐analysis, which included 1484 patients, shows 81.2% survival of at least one twin (CI: 79.1–83.2%). The average survival of at least one twin for the entire population remained within the CI of all but one series. Neither case load, nor stage distribution, nor chronological date of the study affected the survival.

Conclusion

A systematic review of endoscopic laser surgery performed in patients with TTTS failed to show a significant impact of high caseloads, disease severity distribution, or improvements in technique. Copyright © 2010 John Wiley & Sons, Ltd.
Tensile creep behaviour of polymethylpentene–silica nanocomposites
Authors: Dorigato Andrea , Pegoretti Alessandro
Published: January 2010

For the first time, poly(4‐methyl‐1‐pentene) (PMP) nanocomposites were prepared by melt compounding 2 vol% of fumed silica nanoparticles, in order to study the role of the nanofiller surface area and functionalization on the tensile mechanical response of the material, with particular focus on its creep behaviour. The high optical transparency of the polymer matrix was substantially preserved in the nanocomposites, while the mechanical properties (in particular the creep stability) were improved. Dynamic mechanical thermal analysis showed an improvement of the storage modulus, more evident above the glass transition temperature of the polymer matrix. Uniaxial tensile tests evidenced that the elastic modulus of the material was positively affected by the presence of silica nanoparticles, even if a slight reduction of the strain at break was detected. The reduction of the tensile creep compliance was proportional to the surface area of the nanofiller, being more evident at high stresses and elevated temperatures. Findley's law furnished a satisfactory fitting of the creep behaviour of the composites, even at high temperatures. It clearly emerges that the incorporation of fumed silica nanoparticles in PMP can be an effective way to overcome the problem of the poor creep stability of polyolefins, especially at high temperatures and high stresses. Moreover the possibility of retaining the original transparency of the material is fundamental for the production of completely transparent PMP components. Copyright © 2010 Society of Chemical Industry
Protein extraction from the earthworm Eisenia fetida for 2‐DE
Authors: Wang Xing , Chang Li , Wang Gaochan , Sun Zhenjun , Ma Hongbo , Sun Qian , Li Jing
Published: January 2010

We identified an efficient protocol for extracting proteins from whole earthworm, Eisenia fetida, for 2‐DE. Sample preparation is a critical step in a 2‐DE proteome approach and is absolutely essential for obtaining good results. Six protein extraction protocols based on different protein precipitation agents were tested and evaluated using 2‐DE. The methods generated remarkably different 2‐DE protein spot patterns. We conclude that trichloroacetic acid (TCA)‐A eliminates interfering compounds, thus allowing for the efficient resolubilization of proteins. TCA‐A gives good distinction, more bands in 1‐DE gels, and the most number of protein spots in 2‐DE gels. It is also rapid, provides the higher protein yield, and has the less number of steps. To demonstrate the quality of the extracted proteins, we cut several protein spots that were common to four methods from 2‐DE gels, analyzed them using MALDI‐TOF/TOF MS, and tentatively identified them. The classic TCA‐A method proved to be most useful as a standard method of extracting proteins from E. fetida.
Triplet diphenylcarbene protected by iodine and bromine groups
Authors: Hirai Katsuyuki , Bessho Kana , Kitagawa Toshikazu , Tomioka Hideo
Published: January 2010

Diphenyldiazomethane having two iodine and two bromine groups at the ortho positions, (2,6‐dibromo‐4‐tert‐butylphenyl)(2,6‐diiodo‐4‐tert‐butylphenyl)diazomethane (1a‐N2), has been synthesized. Triplet diphenylcarbene 31a is generated from the precursor and is characterized by UV–Vis spectroscopy at low temperature and laser flash photolysis (LFP) techniques at room temperature. Irradiation of 1a‐N2 in a 2‐methyltetrahydrofuran (2‐MTHF) matrix at 77 K gives the UV–Vis spectrum of 31a, but ESR signals that can be assigned to a triplet species are not detected. The LFP of 1a‐N2 in a degassed benzene solution produces the transient absorption ascribable to 31a at 351 nm, which decays in a second‐order process with a rate constant of 0.17 s−1. The first half‐life of 31a is estimated to be 24 s. Triplet carbene 31a is trapped by oxygen to generate benzophenone oxide 1a‐O, with maximum absorbance at 415 nm, with a rate constant of 7.3 × 106 M−1s−1, and also by 1,4‐cyclohexadiene (CHD) to produce the diphenylmethyl radical (1a‐H2, λmax = 380 nm) with a rate constant of 39 M−1s−1. The carbene is also trapped by methanol with a rate constant of 0.30 M−2s−1. Steady‐state irradiation of 1a‐N2 in degassed benzene affords only a small amount of the phenanthrene 2a as an assignable product. Copyright © 2010 John Wiley & Sons, Ltd.
Interactions of carbon nanotubes with pyrene‐functionalized linear‐dendritic hybrid polymers
Authors: Bahun Greg J. , Adronov Alex
Published: January 2010

A series of linear‐dendritic hybrid polymers, containing pyrene units at the periphery of aliphatic polyester dendrons, were prepared for the purpose of dispersing shortened single‐walled carbon nanotubes (SWNTs) in tetrahydrofuran (THF). The prepared hybrids contained 1, 2, 4, 8, or 16 (G0 through G4) pyrene units and a linear segment composed of polystyrene. It was found that a minimum of four pyrene units was necessary to form a strong enough interaction with SWNTs to enable steric stabilization in solution, when using a linear polymer segment of 11.5 kDa. Increasing either the number of pyrene units per polymer chain or the length of the polymer segment to 18.0 kDa did not improve nanotube solubility, whereas decreasing the polymer length resulted in significantly less effective nanotube dissolution. The G4 dendron alone, without the linear polystyrene segment, was also found to impart solubility to the nanotubes in THF. Interactions between the series of linear‐dendritic hybrids and full‐length multiwalled carbon nanotubes were also investigated, and it was found that the polymers exhibited strong interactions with the multiwalled carbon nanotube surface, resulting in the formation of stable solutions. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1016–1028, 2010
Behaviors of self‐assembled diblock copolymer with pendant photosensitive azobenzene segments
Authors: Liu Jui‐Hsiang , Chiu Yi‐Hong
Published: January 2010

A novel monomer, ethyl 4‐[4‐(11‐methacryloyloxyundecyloxy)phenyl azobenzoyl‐oxyl] benzoate, containing a photoisomerizable NN group was synthesized. The monomer was further diblock copolymerized with methyl methacrylate. Amphiphilic diblock copolymer poly(methyl methacrylate‐block‐ethyl 4‐[4‐(11‐methacryloyloxyundecyloxy)phenyl azobenzoyl‐oxyl] benzoate (PMMA‐b‐PAzoMA) was synthesized using atom transfer radical polymerization. The reverse micelles with spherical construction were obtained with 2 wt % of the diblock copolymer in a THF/H2O mixture of 1:2. Under alternating UV and visible light illumination, reversible changes in micellar structure between sphere and rod‐like particles took place as a result of the reversible E‐Z photoisomerization of azobenzene segments in PMMA‐b‐PAzoMA. Microphase separation of the amphiphilic diblock copolymer in thin films was achieved through thermal and solvent aligning methods. The microphases of the annealed thin films were investigated using atom force microscopy topology and scanning electron microscopy analyses. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1142–1148, 2010
Synthesis and nonlinear optical properties of novel Y‐type polyurethane containing tricyanovinylthiazole with enhanced thermal stability of second harmonic generation
Authors: No Hyo Jin , Jang Han‐Na , Jin Cho You , Lee Ju‐Yeon
Published: January 2010

A novel Y‐type poly[iminocarbonyloxyethyl‐5‐methyl‐4‐{2‐thiazolylazo‐4‐(1,2,2‐tricyanovinyl)}resorcinoxyethyloxycarbonylimino‐(3,3′‐dimethoxy‐4,4′‐biphenylene)] 4 containing 5‐methyl‐4‐{5‐(1,2,2‐tricyanovinyl)‐2‐thiazolylazo}resorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. Polyurethane 4 is soluble in common organic solvents such as acetone and N,N‐dimethylformamide. It showed a thermal stability up to 250 °C in thermogravimetric analysis thermogram and the glass‐transition temperature (Tg) obtained from differential scanning calorimetry thermogram was around 118 °C. The second harmonic generation coefficient (d33) of poled polymer films at 1560 nm fundamental wavelength was around 8.43 × 10−9 esu. The dipole alignment exhibited a thermal stability even at 12 °C higher than Tg, and there was no SHG decay below 130 °C due to the partial main‐chain character of the polymer structure, which is acceptable for NLO device applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1166–1172, 2010
N‐vinylcaprolactam‐based microgels for biomedical applications
Authors: Imaz Ainara , Forcada Jacqueline
Published: January 2010

Three types of poly(N‐vinylcaprolactam)‐based temperature‐sensitive microgel particles were synthesized by emulsion polymerization. The uptake of a model drug (calcein) into the particles was analyzed in terms of the amount of calcein absorbed and equilibrium–swelling degree. By incubating the microgels with primary neuronal cell cultures of embrionary rats, cell viability and biocompatibility tests were carried out. The results show that the driving force for the model drug to penetrate into the microgel particles is H‐bonding associations. On the other hand, cell death was microgel concentration and incubation period dependent. Microgels can be stored in a dried state and resuspended in water when necessary without changing their swelling–deswelling ability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1173–1181, 2010
A novel thermotropic liquid crystalline copolyester containing phosphorus and aromatic ether moity toward high flame retardancy and low mesophase temperature
Authors: Bian Xiang‐Cheng , Chen Li , Wang Jun‐Sheng , Wang Yu‐Zhong
Published: January 2010

A series of thermotropic liquid crystalline polyesters containing phosphorus and aromatic ether groups (TLCP‐AEs) were synthesized from p‐acetoxybenzoic acid (p‐ABA), terephthalic acid (TPA), 4,4′‐oxybis(benzoic acid) (OBBA), and acetylated 2‐(6‐oxid‐6H‐dibenz(c,e) (1,2) oxaphosphorin 6‐yl) 1,4‐benzenediol (DOPO‐AHQ). The chemical structure and the properties of TLCP‐AEs were characterized by Fourier‐transform spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), X‐ray diffraction (XRD), thermogravimetry analysis (TGA), scanning electronic microscopy (SEM), polarizing optical microscopy (POM), limiting oxygen index, and UL‐94 tests, respectively. The results showed that TLCP‐AEs had low and broad mesophase temperatures (230–400 °C). TLCP‐AEs also showed excellent thermal stability; their 5%‐weight‐loss temperatures were above 440 °C and the char yields at 700 °C were higher than 45 wt %. All TLCP‐AE polyesters exhibited high flame retardancy with a LOI value of higher than 70 and UL‐94 V‐0 rating. The SEM observation revealed that TLCP‐AEs had good fibrillation ability. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1182–1189, 2010
Synthesis of dual pH/temperature‐responsive polymers with amino groups by living cationic polymerization
Authors: Oda Yukari , Kanaoka Shokyoku , Aoshima Sadahito
Published: January 2010

For the precision synthesis of primary amino functional polymers, cationic polymerization of a phthalimide‐containing vinyl ether monomer precursor, 2‐vinyloxyethyl phthalimide (PIVE), was examined using a base‐assisting initiating system. Living polymerization of PIVE in CH2Cl2 in the presence of 1,4‐dioxane as an added base yielded nearly monodispersed polymers (Mw/Mn < 1.1) and higher molecular weight polymers, which have never been obtained using other initiating systems. Furthermore, block copolymers with hydrophobic or hydrophilic groups could be prepared. The deprotection of the pendant phthalimide groups gave well‐defined pH‐responsive polymers with pendant primary amino groups. Dual‐stimuli–responsive block copolymers having a pH‐responsive polyamine segment and a thermosensitive segment self‐assembled in water in response to both pH and temperature. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1207–1213, 2010
Titanium complexes of dialkanolamine ligands as initiators for living ring‐opening polymerization of ε‐caprolactone
Authors: Piskun Yulia A. , Vasilenko Irina V. , Kostjuk Sergei V. , Zaitsev Kirill V. , Zaitseva Galina S. , Karlov Sergei S.
Published: January 2010

The titanium complexes with one (1a, 1b, 1c) and two (2a, 2b) dialkanolamine ligands were used as initiators in the ring‐opening polymerization (ROP) of ε‐caprolactone. Titanocanes 1a and 1b initiated living ROP of ε‐caprolactone affording polymers whose number‐average molecular weights (Mn) increased in direct proportion to monomer conversion (Mn ≤ 30,000 g mol−1) in agreement with calculated values, and were inversely proportional to initiator concentration, while the molecular weight distribution stayed narrow throughout the polymerization (Mw/Mn ≤ 1.2 up to 80% monomer conversion). 1H‐NMR and MALDI‐TOF‐MS studies of the obtained poly(ε‐caprolactone)s revealed the presence of an isopropoxy group originated from the initiator at the polymer termini, indicating that the polymerization takes place exclusively at the Ti–OiPr bond of the catalyst. The higher molecular weight polymers (Mn ≤ 70,000 g mol−1) with reasonable MWD (Mw/Mn ≤ 1.6) were synthesized by living ROP of ε‐caprolactone using spirobititanocanes (2a, 2b) and titanocane 1c as initiators. The latter catalysts, according MALDI‐TOF‐MS data, afford poly(ε‐caprolactone)s with almost equal content of α,ω‐dihydroxyl‐ and α‐hydroxyl‐ω(carboxylic acid)‐terminated chains arising due to monomer insertion into “Ti–O” bond of dialkanolamine ligand and from initiation via traces of water, respectively. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1230–1240, 2010
Kinetics of degradation of Lycium barbarum polysaccharide by ultrasonication
Authors: Zhu Xiaohe , Zhang Honglei , Yan Hong , Yi Jianping , Zhong Rugang
Published: January 2010

Lycium barbarum polysaccharide (LBP) was subjected to ultrasonic degradation under the controlled conditions, such as, temperature, irradiation time, initial pH value, and concentration of solution. The ultrasonic degradation of LBP was demonstrated by the changes of intrinsic viscosity. Viscometry was used to study the degradation behavior and a kinetic model was developed to estimate the degradation rate. The results showed that the degradation rate was reduced with the increase of solution concentration and pH, and increased with increase of temperature. The relationship between the number average molar mass (Mn) and intrinsic viscosities as interpreted using the Mark‐Houwink equation suggested that LBP adopted a flexible coil conformation in aqueous solution. The activation energy of ultrasonic degradation of LBP is 26.5 kJ/mol, which indicates that the ultrasonic degradation is a convenient, time saving, and cost‐efficient method for obtaining a desired molecular weight. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 509–513, 2010
Effect of crosslinking on the secondary relaxation in polyvinylethylene
Authors: Casalini R. , Roland C. M.
Published: January 2010

The effect of network formation on the secondary (Johari–Goldstein) β‐relaxation was investigated for polyvinylethylene (PVE). Crosslinking affects the segmental (α‐) process in the usual fashion, the networks exhibiting slower and more temperature‐sensitive dynamics. However, the effect on the β‐process is the opposite. The secondary relaxation becomes faster and the activation energy slightly decreases with crosslinking. The strength of the intermolecular cooperativity governing the behavior of the α‐process was assessed using the coupling model, with consistent results obtained from analysis of both the timescale separating the α‐ and β‐relaxations and the activation energy for the latter. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 582–587, 2010
Aggregation behavior of polystyrene‐b‐poly(ethylene/butylene)‐b‐polystyrene triblock copolymer in N‐methylpyrrolidone
Authors: Ogata Yoichi , Mogi Takeshi , Makita Yutaka
Published: January 2010

Solution property of hydrogenated polystyrene‐b‐poly(ethylene/butylene)‐b‐polystyrene triblock copolymer (SEBS copolymer) was studied by using static light scattering and dynamic light scattering for cyclohexane and N‐methylpyrrolidone (NMP) solutions. From the values of dimensionless parameters ρ, defined as the ratio of radius of gyration 〈S2〉1/2 to hydrodynamic radius RH, and solubility parameters, SEBS copolymer proved to exist as single chain close to random coil in nonpolar cyclohexane, whereas aggregate into the core‐shell micelle consisting of poly(ethylene/butylene) (PEB) core surrounded by PS shell in polar NMP. The core‐shell micelle formed in NMP is composed of 65 polymer chains, having three times larger average chain density (d = 0.12 g cm−3) than a single polymer chain (d = 0.04 g cm−3) in cyclohexane. The comparison with the aggregation behaviors in other solvents demonstrated that the aggregate compactness of the copolymer depended largely on solvent polarity, resulting in formation of the highly dense PEB core (Rc = 4.5 nm) and the thick PS shell (ΔR = 22.9 nm) in high‐polar NMP. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 588–594, 2010
High hydrogen dilution and low substrate temperature cause columnar growth of hydrogenated amorphous silicon
Authors: Bronsveld Paula C. P. , Mates Tomas , Fejfar Antonin , Kočka Jan , Rath Jatindra K. , Schropp Ruud E. I.
Published: January 2010

Columnar growth was observed in the amorphous part of mixed phase layers deposited at very low substrate temperatures. The width of the columns and the layer thickness at which they are first distinguishable in a cross‐sectional transmission electron microscope (X‐TEM) image, about 120 nm, is similar for the substrate temperature range of 40–100 °C, but the columns are less well developed when either the substrate temperature is increased or the dilution ratio is lowered. This growth behaviour and the incubation layer are attributed to hydrogen‐induced surface diffusion of growth precursors resulting in an amorphous–amorphous roughness transition.
High deposition rate nanocrystalline silicon with enhanced homogeneity
Authors: Verkerk Arjan , Rath Jatindra K. , Schropp Ruud
Published: January 2010

High rate growth of hydrogenated nanocrystalline silicon (nc‐Si:H) brings additional challenges for the homogeneity in the growth direction, since the start‐up effects affect a larger portion of the film, and the very high degree of depletion increases the influence of back diffusion from the inactive region into the plasma zone. It was calculated that back diffusion plays a role in the regime for high deposition rate (4.5 nm/s) via the residence time for particles in the plasma and the corresponding diffusion length for silane from outside the plasma. The stabilization time for back diffusion was derived and found to be on the order of tens of seconds. Experiment showed that the incubation layer for nc‐Si:H is very thick in films deposited at a high rate compared to films deposited in a regime of lower deposition rate. The use of a hydrogen plasma start greatly reduced this incubation layer. Further control of the crystalline fraction could be achieved via slight reduction of the degree of depletion via the silane flow.
Comparison of metal Schottky contacts on n‐Ge (100) at different annealing temperatures
Authors: Chawanda A. , Nyamhere C. , Auret F. D , Mtangi W. , Diale M. , Nel J. M.
Published: January 2010

SiOC films made by the inductively coupled plasma chemical vapor deposition were researched the relationship between the dielectric constant and the chemical shift. SiOC film had the main Si‐O‐C bond with the molecule vibration mode in the range of 930∼1230 cm‐1 which consists of C‐O and Si‐O bonds related to the cross link formation according to the dissociation and recombination. The C‐O bond originated from the elongation effect by the neighboring highly electronegative oxygen atoms at terminal C‐H bond in Si‐CH3 of 1270 cm‐1. However, the Si‐O bond was formed from the second ionic sites recombined after the dissociation of Si‐CH3 of 1270 cm‐1. Increment of Si‐O bond in the Si‐O‐C main bond contributed to increase the hardness and decrease the roughness because of the decreasing of the carbon content witch is related to the space effect. The dielectric constant of SiOC film was decreased by lowering the polarization which consists of the ionic and electronic polarity. Increment of Si‐O bond in a right shoulder at the main bond was interpreted by the red shift observed in FTIR spectra. Moreover, the increment of Si‐O bond and decrement of carbon content induced to decrease the ionic polarity and then decreased the dielectric constant (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Interface properties and junction behavior of Pd contact on ZnO thin film grown by vacuum deposition technique
Authors: Ali Ghusoon M. , Dwivedi A. D. D. , Singh S. , Chakrabarti P.
Published: January 2010

In this paper we explain the results of our experimental investigation on interface properties and junction behavior of Pd contact on ZnO thin film based Schottky diode. We used a conventional vacuum evaporation deposition unit for sequential deposition of ZnO film and metallic layer. For the first time a high quality Pd/ZnO Schottky diode is fabricated successfully in our laboratory by vacuum evaporation method. The I‐V and C‐V characteristics of the devices were studied by using microprobe arrangement. The parameter such as ideality factor, leakage current, resistance‐area‐product, carrier concentration and barrier height were extracted from the measured data. The surface morphological and the structural properties of thin film were studied by atomic force microscope. The optical band gap of thin film was determined using UV‐visible spectrophotometer. The device fabricated by a simple technique exhibited excellent stability for use as an electronic or optoelectronic component. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Designing the Si(100) conversion into SiC(100) by Ge
Authors: Nader Richard , Niebelschütz Florentina , Kulikov Dmitri V. , Kharlamov Vladimir V. , Trushin Yurii V. , Masri Pierre , Pezoldt Jörg
Published: January 2010

The deposition of Germanium (Ge) prior to the conversion of Si(100) into 3C‐SiC(100) results in changes of the structure and surface morphology of the formed silicon carbide layer. First of all it reduces the thickness of the 3C‐SiC layer grown during the conversion process and therefore the probability of voids formation. Secondly, it increases the nucleation density of the formed 3C‐SiC nuclei and therefore, decreases the grain size at Ge coverages below two monolayers. These affect the roughness of the SiC surface positively by modifying the width of the SiC‐Si interface. If the Ge coverages exceed two monolayers the structural and morphological properties begin to degrade. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ab initiog ‐tensor calculation for paramagnetic surface states: hydrogen adsorption at Si surfaces
Authors: Gerstmann U. , Rohrmüller M. , Mauri F. , Schmidt W.G.
Published: January 2010

Ab initio calculations of the electronic g ‐tensor of paramagnetic states at surfaces are presented taking the adsorption of hydrogen atoms at silicon surfaces as an example. We show that for silicon surfaces with different hydrogen coverages, the g ‐tensor is by far more characteristic than the hyperfine splitting of the Si dangling bonds or the adsorbed H atoms.

This holds also in the case of powder spectra (e.g. amorphous or microcrystalline material) where only the angular average of the spectra is available from experiments. Hence, the ab initio calculation of the g ‐tensor should be in general a basic key to a better understanding of the microscopic structure of paramagnetic surfaces or interfaces (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural and optical properties of CdS nanocrystals grown in water‐soluble diblock copolymer
Authors: Celalettin Baykul M. , Rüzgar Hilal , Arman Emine , Baş Yasemin , Bütün Vural
Published: January 2010

Methoxy‐capped poly(ethylene glycol) (PEG) was used to prepare ATRP initiator (PEGBr). PEGBr was copolymerised with t ‐butyl methacrylate (tBMA) by using atom transfer radical polymerization (ATRP) chemistry. tBMA residues were converted to methacrylic acid (MAA) by acidic hydrolysis under mild conditions to give well‐defined PEG–b ‐PMAA diblock copolymers. Near‐monodisperse micellization was observed by the addition of CdCl2 (1.0 wt%) into PEG–b ‐PMAA diblock copolymer solution at pH 11.0 due to complexation of MAA‐ with Cd+2 ions. After addition of thioacetamide into the micellar solution, the Cd+2 cations in the resulting micelles were converted to CdS to obtain CdS nanocrystals in the micelles.

The band gap of CdS nanocrystals was obtained from the absorbance measurements in the visible range and found to be 2.4 eV. Electrical resistivity of CdS nanocrystals was found to be 0.21 Ωcm. The thickness of the CdS thin films on glass substrate was found to be 131.14 nm. XRD pattern of CdS nanocrystals has shown that (111), (110), (021), and (220) diffractions are related to the cubic CdS nanocrystals. Preferred crystallographic orientation of the CdS nanocrystals is (110). TEM results have shown that grain sizes of CdS thin films vary between 64 and 133 nm (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of ZnS:Mn nanocrystals
Authors: Ahmed F. , En Naciri A. , Grob J. J.
Published: January 2010

The optical properties of Mn‐doped zinc sulfide (ZnS) nanocrystals embedded in SiO2 matrix are studied by spectroscopic ellipsometry (SE). The crystals are obtained by sequential multi‐energy ion implantation of Zn, S, and Mn into a silica layer grown on Si(111) followed by a subsequent annealing for 30 min at 900 °C. The formation of the nanocrystals is evidenced by transmission electron microscopy. The application of a critical‐point based model for the analysis of the SE data yields die dielectric function (DF) between 0.6 and 6.5 eV. A pronounced shift of the absorption edge towards higher energies is detected for the nanocrystals In comparison to bulk ZnS (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structure and optical properties of the Sb‐stabilized GaSb(001) surface
Authors: Hogan Conor , Magri Rita , Del Sole Rodolfo
Published: January 2010

We suggest a model for the c(2 x 6) phase of the Sbstabilized GaSb(001) surface, whereby Sb atoms in the second layer are partially substituted by Ga. This ‘doping’ effect enables the surface to fulfil the electron counting rule whilst maintaining a reconstruction based on long dimer chains.

Total energy calculations verify that the suggested reconstruction is relatively stable, and calculations of the reflectance anisotropy spectra confirm that it comprises a major component of the largely disordered surface (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Voigt effect measurement on PLD grown NiO thin films
Authors: Scarlat Camelia , Mok Kah Ming , Zhou Shengqiang , Vinnichenko Mykola , Lorenz Michael , Grundmann Marius , Helm Manfred , Schubert Mathias , Schmidt Heidemarie
Published: January 2010

NiO has great potential applications in spin valves, magnetooptical sensors, optical fibers, solar thermal absorbers, and in nonvolatile resistive random access memory devices. In our study NiMnO and NiMnLiO films have been grown on double‐side polished r‐plane sapphire substrates by pulsed laser deposition (PLD). We measured the complex Voigt angle using the polarized light from a HeCd laser, a Glan Taylor polarizer, a Hinds PEM‐100 [1] and two Lock‐Ins. The Voigt effect is a second order magnetooptic effect [2]. The polarization state of light after transmission through a sample consisting of ca. 1 μm thick, weak ferromagnetic NiO thin on purely diamagnetic r‐plane sapphire substrates has been modelled using the 4×4 matrix formalism [3] in dependence of an external magnetic field applied in‐plane, i.e. in Voigt configuration. The modelling results revealed that for the diamagnetic sapphire substrate the Voigt angle depends parabolically on the external magnetic field and that the weak ferromagnetic NiO thin films change the parabolic dependence of the Voigt angle in the range of ±0.1 T to a flat‐top shape in agreement with the experimentally determined Voigt angle (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Domain boundaries of the Si(111)‐Ge5×5 reconstruction
Authors: Mark A. G. , McLean A. B.
Published: January 2010

The boundaries that form between domains of the 5×5 reconstruction of Si(111)‐Ge are examined. A notation for indexing the boundaries is developed, and their symmetry properties are discussed. A preparation procedure that enhances the density of such boundaries while en‐couraging their uniform growth is described. The notation is illustrated using a selection of observed examples (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)