bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinetic study of nordihydroguaiaretic acid recovery from Larrea tridentata by microwave‐assisted extraction
Authors: Martins Silvia , Aguilar Cristóbal N. , Garza‐Rodriguez Iliana de la , Mussatto Solange I. , Teixeira José A.
Published: April 2010

BACKGROUND: Nordihydroguaiaretic acid (NDGA) is a powerful antioxidant with biological activities of great interest in several health areas, including antiviral, cancer chemopreventive, and antitumorgenic. Little information is available on extraction methods of NDGA from Larrea tridentata. Hence, the aim of this study was to develop a rapid and effective microwave‐assisted extraction (MAE) method for NDGA recovery from Larrea tridentata leaves, and to compare the results obtained with those found using conventional heat‐reflux extraction (HRE).

RESULTS: Extraction time for similar NDGA yields was significantly reduced from 18 to 1 min when MAE was used instead of HRE. Optimum conditions for NDGA extraction (3.79 ± 0.65%) consisted in using 50% methanol as extraction solvent in a solid/liquid ratio of 1/10 g mL−1. Micrographs demonstrated that the improvement in NDGA extraction by MAE might be related to a greater extent of cell rupture of the plant material. Extracts obtained by MAE exhibited antiradical activity only slightly lower than those obtained by HRE.

CONCLUSIONS: MAE proved to be a faster and more efficient method for NDGA extraction from Larrea tridentata leaves than HRE. The better results for NDGA extraction by MAE might be explained by the greater extent of cell rupture of plant material during the extraction process. Copyright © 2010 Society of Chemical Industry
Synthesis and evaluation of 2‐, 4‐, 5‐substituted nitroimidazole‐iminodiacetic acid‐99mTc(CO)3 complexes to target hypoxic tumors
Authors: Mallia Madhava B. , Subramanian Suresh , Mathur Anupam , Sarma H. D. , Venkatesh Meera , Banerjee Sharmila
Published: April 2010

Determination of hypoxia in tumor is an important problem in the clinical management of cancer. Towards this, a series of differently substituted nitroimidazoles, viz. 2‐nitro, 4‐nitro and 5‐nitroimidazole iminodiacetic acid (IDA) derivatives were synthesized and radio‐labeled with a [99mTc(CO)3(H2O)3]+ core. The corresponding 185/187Re(CO)3 analogue of 2‐nitroimidazole‐IDA‐99mTc(CO)3 complex was also prepared and characterized to elucidate the mode of bonding between the ligand and the M(CO)3 core (M=99mTc, 185/187Re). All the three nitroimidazole‐IDA‐99mTc(CO)3 complexes could be prepared in over 95% yield determined by HPLC. The three complexes were then evaluated in a suitable animal model bearing tumor. Though the in vivo accumulation of complexes in hypoxic tissue is governed by factors such as lipophilicity, charge, etc., the variation in accumulation in hypoxic tissue, in the present case, could be explained by considering the reported values of single electron reduction potential of the respective nitroimidazoles. Among the three derivatives studied, the 2‐nitroimidazole‐IDA‐99mTc(CO)3 complex produced the best result followed by the 5‐nitroimidazole complex. Copyright © 2010 John Wiley & Sons, Ltd.
Preparation of α‐labeled aldehydes by base‐catalyzed exchange reactions
Authors: Ariza Xavier , Asins Guillermina , Garcia Jordi , Hegardt Fausto G. , Makowski Kamil , Serra Dolors , Velasco Javier
Published: April 2010

A simple, efficient protocol for the preparation of α‐labeled aldehydes based on H/D exchange catalyzed by 4‐(N,N‐dimethylamino)pyridine or Et3N is described. High chemical yields and ratios of isotope incorporation were obtained even when small amounts (∼1 mmol) of aldehyde were used. Copyright © 2010 John Wiley & Sons, Ltd.
Uncertainty analysis of a commercial microwave noise temperature measurement system using Monte Carlo simulations
Authors: Weatherspoon Mark H. , Smith R. Joe
Published: April 2010

A Monte Carlo simulation, a non‐linear fitting routine, and an uncertainty extraction routine are used to analyze the uncertainty of a commercial microwave noise temperature measurement system. Measured data for an S/C band synthetic FET‐based cold load, two microwave solid‐state noise diode hot loads, and an ambient load is obtained, and the measurement system uncertainties are subsequently assessed using different DUTs. An estimation of the measurement system uncertainties is determined for a range of DUT temperatures, and the results are consistent with the noise temperature uncertainties calculated from the measured data at the same frequency. Copyright © 2010 John Wiley & Sons, Ltd.
Raman spectroscopy of hydrogen‐arsenate group (AsO3OH) in solid‐state compounds: cobalt mineral phase burgessite Co2(H2O)4[AsO3OH]2·H2O
Authors: Čejka Jiří , Sejkora Jiří , Bahfenne Silmarilly , Palmer Sara J. , Plášil Jakub , Frost Ray L.
Published: April 2010

Raman spectrum of burgessite, Co2(H2O)4[AsO3OH]2· H2O, was studied, interpreted and compared with its infrared spectrum. The stretching and bending vibrations of (AsO3) and As‐OH units, as well as the stretching, bending and libration modes of water molecules and hydroxyl ions were assigned. The range of OH···O hydrogen bond lengths was inferred from the Raman and infrared spectra of burgessite. The presence of (AsO3OH)2− units in the crystal structure of burgessite was proved, which is in agreement with its recently solved crystal structure. Raman and infrared spectra of erythrite inferred from the RRUFF database are used for comparison. Copyright © 2010 John Wiley & Sons, Ltd.
The effect of topical sodium thiosulfate in experimentally induced myringosclerosis
Authors: Park Yong Ho , Park Chan Hee , Kim Hak Jun
Published: April 2010

Objectives/Hypothesis:

The purpose of this study was to investigate the effect of topical sodium thiosulfate (STS) in experimentally induced myringosclerosis (MS).

Study Design:

A prospective experimental animal study.

Methods:

Thirty Wistar albino rats were bilaterally myringotomized. The right ears were treated with STS or saline daily, and the left ears were left untreated and used as controls. The tympanic membranes were observed by otoendoscopy weekly, and tympanometric measurements were performed. All animals were histopathologically examined for myringosclerotic plaques.

Results:

Under otoendoscopy, myringosclerosis were observed around the handle of the malleus and near the annular region. The numbers of myringosclerotic ears were significantly more frequent in control and saline groups compared with the STS group (P < .05), and the formation of MS was more severe in control and saline groups compared with STS group (P < .05). Using tympanometric measurement, significantly reduced magnitudes of maximum admittance were observed in control and saline groups compared to normal and STS groups (P < .05). Under histopathologic examination, the tympanic membrane of the STS group appeared thinner than the control group (P < .05), with reduced calcium deposition than control and saline groups.

Conclusions:

Our results show that sodium thiosulfate has a preventive role in the development of myringosclerosis in the experimental animal model. Laryngoscope, 2010
Microscopic versus endoscopic pituitary surgery: A systematic review
Authors: Rotenberg Brian , Tam Samantha , Ryu Won Hyung A. , Duggal Neil
Published: April 2010

Objectives/Hypothesis:

To critically review current literature comparing microscopic versus endoscopic surgery in the treatment of pituitary adenomas.

Study Design:

Systematic review of the literature.

Methods:

All English language literature published between January 1989 and June 2009 on PubMed were eligible for inclusion. Inclusion criteria were: direct comparison between microscopic and fully endoscopic approaches and surgery performed with the intent to treat a pituitary adenoma. Endoscopic‐assisted comparisons and studies comparing outcomes with previous literature were excluded. Technical notes, case reports, letters, and comments were also excluded. Included studies were categorized according to level of evidence and evaluated for quality using a modified Downs and Black scale. Data was extracted and compared between studies.

Results:

Of the 3,586 studies retrieved from the search strategy, 11 studies met the inclusion and exclusion criteria. Various outcomes measures were used including: operating time, extent of tumor resection, postoperative normalization of hormone levels, incidence of complications, length of hospital stay, and patient pain and discomfort. The endoscopic approach decreased operating time, lumbar drains, immediate postoperative diabetes insipidus, some rhinologic complications, length of hospital stay, and patient pain and discomfort. Other outcome measures were comparable between the two approaches.

Conclusions:

The literature comparing endoscopic and microscopic pituitary surgery favors the endoscopic approach for pituitary surgery. Major outcome measures (extent of tumor resection, changes in hormone levels) do not differ between the two approaches. Complications, time in the operating room and hospital, and patient discomfort are significantly less with the endoscopic approach. Laryngoscope, 2010
Factors associated with nonparticipation in one‐year quality‐of‐life assessment in patients with head and neck squamous cell carcinoma
Authors: Gourin Christine G. , Kaboli Kavon C. , Boyce Brian J. , Burkhead Lori M.
Published: April 2010

Objectives/Hypothesis:

To identify factors associated with nonparticipation in long‐term quality‐of‐life (QOL) analysis in head and neck squamous cell cancer (HNSCC) patients.

Study Design:

Restrospective analysis of prospectively collected data.

Methods:

Two hundred sixty‐one previously untreated HNSCC patients were prospectively evaluated using the University of Washington QOL questionnaire. Questionnaires were administered before treatment and at 1 year following treatment. Patients without data at 1 year were classified as nonparticipants.

Results:

At 1 year, 152 patients (58%) had complete QOL data. Nonparticipants differed from participants by stage, comorbidity, and disease status, with a greater proportion of patients with advanced stage disease, advanced comorbidity, and recurrent disease participating in QOL analysis at 1 year (P < .05). No significant differences were found between nonparticipants and participants with respect to age, race, primary site, treatment, travel distance, or socioeconomic variables. Multiple linear regression analysis showed differences in initial QOL scores between participants and nonparticipants only for activity, with lower mean initial scores for nonparticipants (β = −9.9, 95% confidence interval, −16.8 to −3.0; P = .005). Multiple logistic regression demonstrated significant differences in the odds of nonparticipation at 1 year for males (odds ratio [OR] 0.4, P = .01), T4 disease (OR 0.3, P = .001), uninsured patients (OR 2.8, P = .007), recurrent disease (OR 0.2, P < .0001), and comorbidity (OR 0.5, P = .025), after controlling for all other variables.

Conclusions:

Long‐term QOL analysis may be biased by greater participation from patients who require greater medical attention because of advanced tumor stage, recurrent disease, or comorbidity, whereas patients without insurance are under‐represented. These findings suggest limitations to the interpretation and application of long‐term QOL data. Laryngoscope, 2010
Defining milestones toward competency in mastoidectomy using a skills assessment paradigm
Authors: Francis Howard W. , Masood Hamid , Laeeq Kulsoom , Bhatti Nasir I.
Published: April 2010

Objectives/Hypothesis:

To establish milestones toward achievement of surgical competency by using an objective assessment tool designed to measure the development of mastoidectomy skills in the operating room (OR).

Study Design:

Prospective longitudinal validation study.

Methods:

Fifty‐six evaluations were conducted in the OR on nine otolaryngology residents from PGY (postgraduate year) 2 to PGY 5 over a period of 3 years. Technical performance was measured over time using a task‐based checklist developed for assessment of mastoidectomy skills.

Results:

Three sets of technical milestones represented achievement of competency for progressively more complicated procedural steps: the first set was achieved after a mean of 6 ± 4.3 cases, the second set after 9 ± 6.7 cases (range of mean = 8–10 cases), and the third set after 13 ± 6.4 cases (range of mean = 12–14 cases).

Conclusions:

The acquisition of mastoidectomy skills can be integrated into surgical teaching in the OR, and this approach yields information that can aid individual skill development and program improvement. The identification of milestones in particular can help establish training benchmarks toward achievement of competency and in identifying trainees in need of remediation.
Evaluating the clinical usefulness of structured questions in parosmia assessment
Authors: Landis Basile N. , Frasnelli Johannes , Croy Ilona , Hummel Thomas
Published: April 2010

Objectives/Hypothesis:

Parosmia and phantosmia relate to distorted odor perceptions. Little is known about their clinical significance. Measuring phantosmia and parosmia is still not possible. Today, assessment of parosmia or phantosmia relies mainly upon the patient's interview and the physician's experience. Therefore, we investigated the clinical usefulness of four structured questions in comparison to the patient's history regarding their accuracy in terms of the presence of odor distortions.

Study Design:

Tertiary care center outpatient clinic analyses.

Methods:

Responses from 193 patients were analyzed. All patients underwent full olfactory work‐up (ear, nose, and throat examination, Sniffin' Sticks testing, structural brain imaging) and filled in a questionnaire with four parosmia questions and six questions regarding characteristics and severity of the parosmia. These responses formed the bases of a numerical parosmia score.

Results:

Patients with parosmia showed significantly lower parosmia scores (P <.001) when compared to either patients with phantosmia or patients without odor distortions. Two questions could be identified that showed a high association to the presence or absence of parosmia.

Conclusions:

The present results confirm reports on the high frequency of parosmia and phantosmia among patients suffering from olfactory disorders. A parosmia score could be established that distinguishes between patients with or without odor distortions. The score provides valuable information regarding the presence or absence of parosmia, thus helping the physician during the patient's evaluation. Laryngoscope, 2010
An easy method for fitting conventional endoscopes for pneumatic video Otoscopy
Authors: Pau Hans Wilhelm , Strenger Tobias
Published: April 2010

Laryngoscope, 2010
Creating a cross‐institutional grading scale for temporal bone dissection
Authors: Wan Dinah , Wiet Gregory J. , Welling D. Bradley , Kerwin Thomas , Stredney Don
Published: April 2010

Objectives/Hypothesis:

There is increasing interest in objective assessment of surgeon competence. In the field of otolaryngology, several surgical training programs, including The Ohio State University, the University of Toronto, and Stanford University, have pursued standardized criteria to rate their trainees' performance in the initial steps of temporal bone dissection (complete mastoidectomy with facial recess approach). Although these assessment metrics require the completion of similar basic components integral to successful temporal bone dissection, certain listed criteria are unique to each institution. Our aim was to establish a more standardized set of criteria that can be used across different institutions to objectively assess temporal bone dissection. We translated these new criteria into automated metrics in our temporal bone dissection simulator to achieve even more objective grading of temporal bone dissections.

Study Design:

Cross‐sectional study/survey.

Methods:

The temporal bone assessment criteria developed by each of the three aforementioned institutions were compiled into an all‐encompassing scale. This compilation was sent out as an online survey to members of the American Neurotology Society and American Otological Society with instructions to rate the importance of each criterion.

Results:

Criteria that were ranked by >70% of respondents as either “very important” or “important” were used to create the new, cross‐institutional scale for the objective assessment of temporal bone dissection.

Conclusions:

The new assessment scale and its eventual incorporation into the temporal bone surgical simulator will enhance the objectivity of currently existing methods to evaluate surgical performance across different institutions. Laryngoscope, 2010
Model scale generation and microscopic characterisation of tribofilms formed on Fe and Cu alloys
Authors: Grün Florian , Gódor István , Javidi Ataollah , Pondicherry Kartik , Offenbecher Martin , Bertram Rich
Published: April 2010

The layer‐forming properties of different lubricants on technically used tribosystems were investigated. The experiments were carried out on a ring‐on‐disc test set‐up on Fe/Fe‐ and Fe/Cu‐based systems. Three different lubricants were used viz. base oil with detergents (Oil‐A), oil with ZnP‐based additives (Oil‐B) and oil with P‐based additives (Oil‐C). We measured the electrical resistance between the rubbing surfaces. Surface characterisation (light microscopy, SEM/EDX and XPS) and tribometric results show differences in wear and friction properties. Oil‐B showed profound layer formation on steel counterparts and correlation in the amount of Zn and S, P and O, respectively; whereas, none of the above was observed with Oil‐A. Oil‐C, however, showed thin but tribologically effective layer formation on ferrous system and a superior performance for the Fe/Cu system. Copyright © 2010 John Wiley & Sons, Ltd.
Increased ventricular lactate in chronic fatigue syndrome measured by 1H MRS imaging at 3.0 T. II: comparison with major depressive disorder
Authors: Murrough James W. , Mao Xiangling , Collins Katherine A. , Kelly Chris , Andrade Gizely , Nestadt Paul , Levine Susan M. , Mathew Sanjay J. , Shungu Dikoma C.
Published: April 2010

Chronic fatigue syndrome (CFS), a complex illness characterized by fatigue, impaired concentration, and musculoskeletal pain, is often misdiagnosed as a psychiatric illness due to the overlap of its symptoms with mood and anxiety disorders. Using proton magnetic resonance spectroscopic imaging (1H MRSI), we previously measured levels of the major brain metabolites in CFS, in generalized anxiety disorder (GAD), and in healthy control subjects, and found significantly higher levels of ventricular cerebrospinal fluid (CSF) lactate in CFS compared to the other two groups. In the present study, we sought to assess the specificity of this observation for CFS by comparing ventricular lactate levels in a new cohort of 17 CFS subjects with those in 19 healthy volunteers and in 21 subjects with major depressive disorder (MDD), which, like GAD, is a neuropsychiatric disorder that has significant symptom overlap with CFS. Ventricular CSF lactate was significantly elevated in CFS compared to healthy volunteers, replicating the major result of our previous study. Ventricular lactate measures in MDD did not differ from those in either CFS or healthy volunteers. We found a significant correlation between ventricular CSF lactate and severity of mental fatigue that was specific to the CFS group. In an exploratory analysis, we did not find evidence for altered levels of the amino acid neurotransmitters, γ‐aminobutyric acid (GABA) and glutamate + glutamine (‘Glx’), in CFS compared to MDD or healthy controls. Future 1H MRS studies with larger sample sizes and well‐characterized populations will be necessary to further clarify the sensitivity and specificity of neurometabolic abnormalities in CFS and MDD. Copyright © 2010 John Wiley & Sons, Ltd.
A meal on the hoof or wealth in the kraal? Stable isotopes at Kgaswe and Taukome in eastern Botswana
Authors: Murphy Kimmarie A.
Published: April 2010

Iron Age sites associated with the Toutswe tradition in Eastern Botswana date between CE 700–1300 and share a variety of settlement patterns, economic features and material culture. The presence of domestic fauna, settlement structures and concentrations of vitrified dung provide archaeological evidence for herding economies. However, due to factors of preservation and past retrieval techniques, evidence for plant remains is still somewhat limited for the Toutswe sites in Botswana. Additionally, archaeological remains such as flora, fauna and material culture often provide only indirect evidence for their contributions to diet. This study provides new evidence for the diet of individuals from the Toutswe tradition. Given the large numbers of animal remains and residues at Toutswe sites, the expectation is that animal domesticates were also an integral part of the diet. Stable isotopic analysis of human remains indicates that even though domestic cattle and sheep occur in great abundance at Toutswe sites, their contribution to the diet may be minimal. The main source of protein for individuals at Kgaswe and Taukome comes from C4 plants such as sorghum and millet and to a lesser extent, animal products. The practice of maintaining large domestic herds for economic and social reasons rather than for primary subsistence in southern Africa today may have its roots in the Iron Age populations of the region. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis of functionalized conducting polymer “polyanthranilic acid” using various oxidizing agents and formation of composites with PVC
Authors: Gupta Bhavana , Prakash Rajiv
Published: April 2010

Synthesis of carboxyl functionalized polyaniline (PANI) (polyanthranilic acid PANA) is reported based on our recent studies using various oxidizing agents. PANA was synthesized in acidic medium using ammonium peroxodisulfate, hydrogen peroxide, and potassium permanganate as oxidizing agents and their structural, electrochemical, and electrical properties are studied. A comparative study among the polymers formed by various oxidizing agents and also with PANI is made. Various possible oxidation states of PANA are discussed, with the help of electrochemical data. A composite of PANA and polyvinyl chloride (PVC) containing 20% PVC by weight is synthesized and used for the development of solid state pH electrode. The composite was synthesized to improve mechanical strength, stability, and restrict solubility. The pH sensor response is found to be reversible and linear in the pH range 1–7. PANA and PVC (20 wt%) based pH sensors show potential applications in development of pH transducers based sensors/biosensors. Copyright © 2010 John Wiley & Sons, Ltd.
Chitin/polyurethane blends: a thermal and morphological study
Authors: Matsui Mitsuka , Munaro Marilda , Akcelrud Leni
Published: April 2010

Chitin is an abundant natural polymer having important properties such as biocompatibility and biodegradability combined with healing capability. Its use in biomedical applications has been hindered by its poor processing properties such as low solubility and stiffness in the solid state. In an attempt to obtain flexible and more processable chitin‐based materials, we prepared blends of the polymer with a polyurethane containing a soft segment based on biodegradable polycaprolactone. A certain degree of miscibility was found between chitin and the polyurethane, as demonstrated by a shift in the glass transition of the polyurethane observed in dynamical mechanical analyses, with a simultaneous decrease in crystallinity of chitin observed in X‐ray diffraction analyses. A phase inversion of the blends took place for a 50/50 (w/w) composition ratio as demonstrated from thermal, dynamic mechanical, tensile and X‐ray diffraction measurements. Blends of chitin with the polycaprolactone‐based polyurethane can be effectively used to produce tough materials useful in biomedical applications. The mechanical strength of the blends demonstrated that they are able to support tensions above those required for bone replacement, making them good candidates for that purpose. Copyright © 2010 Society of Chemical Industry
Controllable preparation of epoxy‐functionalized magnetic polymer latexes with different morphologies by modified miniemulsion polymerization
Authors: Xu Yawen , Xu Hong , Gu Hongchen
Published: April 2010

The synthesis of functional magnetic polymer latexes (MPLs) with epoxy groups introduced via a modified miniemulsion polymerization route was described. The epoxy group content on the surface could be controlled by seed emulsion followed and characterized by FTIR and zeta potential measurements. We also developed a novel approach to achieve manipulation of the morphology of the MPLs based on kinetic control of the polymerization system. MPLs with different morphologies were obtained ranging from core–shell microstructures, dispersed microstructures to asymmetric microstructure, which were characterized by TEM, DLS, and TGA. The mechanisms of the contribution of kinetic factors such as polymerization rate, reaction time, and temperature contributing to the formation of the different morphologies were also investigated. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2284–2293, 2010
Thermoresponsive brush copolymers with poly(propylene oxide‐ran‐ethylene oxide) side chains via metal‐free anionic polymerization “grafting from” technique
Authors: Zhao Junpeng , Zhang Guangzhao , Pispas Stergios
Published: April 2010

Thermoresponsive brush copolymers with poly(propylene oxide‐ran‐ethylene oxide) side chains were synthesized via a “grafting from” technique. Poly(p‐hydroxystyrene) was used as the backbone, and the brush copolymers were prepared by random copolymerization of mixtures of oxyalkylene monomers, using metal‐free anionic ring‐opening polymerization, with the phosphazene base (t‐BuP4) being the polymerization promoter. By controlling the monomer feed ratios in the graft copolymerization, two samples with the same side‐chain length and different compositions were prepared, both of which possessed high molecular weights and low molecular weight distributions. The results from light scattering and fluorescence spectroscopy indicated that the brush copolymers in their dilute aqueous solutions were near completely solvated at low temperature and underwent slight intramolecular chain contraction/association and much more profound intermolecular aggregation at different stages of the step‐by‐step heating process. Above 50 °C, very turbid solutions, followed by macrophase separation, were observed for both of the samples, which implied that it was difficult for the brush copolymers to form stable nanoscopic aggregates at high temperature. All these observations were attributed, at least partly, to the distribution of the oxyalkylene monomers along the side chains and the overall brush‐like molecular architecture. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2320–2328, 2010
New thiophene‐phenylene‐thiophene acceptor random conjugated copolymers for optoelectronic applications
Authors: Tsai Jung‐Hsun , Chueh Chu‐Chen , Chen Wen‐Chang , Yu Chao‐Ying , Hwang Gue‐Wuu , Ting Ching , Chen En‐Chen , Meng Hsin‐Fei
Published: April 2010

New low band gap thiophene‐phenylene‐thiophene (TPT)‐based donor‐acceptor‐donor random copolymers were synthesized for optoelectronic device applications by a palladium‐catalyzed Stille coupling reaction under microwave heating. The acceptors included 2,3‐bis(4‐(2‐ethylhexyloxy)phenyl)‐5,8‐bis[5′‐bromo‐dithien‐2‐yl‐quinoxalines] (DTQ) and 3,6‐bis(5‐bromothiophen‐2‐yl)‐2,5‐bis(2‐ethyl‐hexyl)‐pyrrolo[3,4‐c]‐pyrrole‐1,4‐dione (DPP). The prepared random copolymers were named as PTPTDTQ0.55, PTPTDTQ0.34DPP0.14, and PTPTDTQ0.26DPP0.34 depending on the copolymer ratio. The optical band gaps (E) of PTPTDTQ0.55, PTPTDTQ0.34DPP0.14, and PTPTDTQ0.26DPP0.34 were 1.74, 1.56, and 1.48 eV, respectively. The hole mobility obtained from the field‐effect transistor devices prepared from PTPTDTQ0.55, PTPTDTQ0.34DPP0.14, and PTPTDTQ0.26DPP0.34 were 2.2 × 10−3, 2.4 × 10−3, and 4.7 × 10−3 cm2 V−1 s−1, respectively, with the on‐off ratios of 4.0 × 104, 4.0 × 104, and 5.3 × 104. It suggested that the significant intramolecular charge transfer between the TPT and acceptor led to the band gap reduction and hole mobility enhancement. Polymer solar cells of these TPT‐based copolymers blended with 1‐(3‐methoxycarbonyl)propyl‐1‐phenyl‐[6,6]‐C‐71 (PC71BM) under illumination of AM 1.5G (100 mW cm−2) solar simulator exhibited a power conversion efficiency (PCE) as high as 3.71%. Besides, the near‐infrared photodetector device prepared from PTPTDTQ0.26DPP0.34 showed a high external quantum efficiency exceeding 32% at 700 nm (under −3 V bias) and fast‐speed response. This study suggests that the prepared TPT‐based donor‐acceptor random copolymers exhibited promising and versatile applications on optoelectronic devices. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2351–2360, 2010
Polyisobutylene‐based polyurethanes. VI. Unprecedented combination of mechanical properties and oxidative/hydrolytic stability by H‐bond acceptor chain extenders
Authors: Erdodi Gabor , Kang Jungmee , Kennedy Joseph P.
Published: April 2010

We describe the design, synthesis, characterization, and testing of novel polyurethanes (PUs) exhibiting unprecedented combinations of outstanding mechanical properties and oxidative/hydrolytic stabilities. This achievement is due to the use of polyisobutylene (PIB) soft segments plus flexible H‐bond acceptor chain extenders (HACEs): the PIB imparts superior oxidative/hydrolytic stability and the HACE produces reinforcing H‐bonds, which lead to outstanding mechanicals. Oxidative/hydrolytic stability was quantitated by retention of tensile strength and elongation after exposure to nitric acid. PUs containing 60–70% PIB retain their mechanical properties, whereas Carbothane®, Bionate®, and Elast‐Eon™, PUs marketed for chemical stability, degrade severely under the same conditions. Various HACEs were identified (e.g., hexaethylene glycol, tripropylene glycol, tributylene glycol, 3,3′‐diamino‐N‐methyl‐dipropylamine, etc.) and their effect on mechanical properties was investigated. A PIB‐ and HACE‐containing PU exhibited 29.2 MPa tensile strength, 620% elongation, and 80 Shore A hardness. Properties were analyzed in terms of stress–strain profiles, differential scanning calorimetry traces, dynamic mechanical thermal analysis plots, and oxidative/hydrolytic stability. The properties of various PIB‐based rubbers, that is, thermoplastic PUs, SIBSTAR®, and thermoset butyl rubber are compared. The novel PUs are promising candidates for biomaterials and industrial applications where a combination of mechanical properties and oxidative/hydrolytic stability is of the essence. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2361–2371, 2010
Photopolymerization of poly(ethylene glycol) dimethacrylates: The influence of ionic liquids on the formulation and the properties of the resultant polymer materials
Authors: Chesnokov Sergey A. , Zakharina Marya Yu. , Shaplov Alexander S. , Lozinskaya Elena I. , Malyshkina Inna A. , Abakumov Gleb A. , Vidal Frederic , Vygodskii Yakov S.
Published: April 2010

The photo‐initiated polymerization of poly(ethylene glycol)dimethacrylates [PEGDM(n)] in the presence of various ionic liquids (ILs) is reported. The influence of ILs concentrations as well as of their nature upon the photopolymerization kinetics was studied in detail. It was found that according to reactive ability in bulk and in solution photopolymerization, the investigated monomers can be divided into two groups: PEGDM(1)–PEGDM(2)–PEGDM(3) and PEGDM(4)–PEGDM(7‐8). ILs slightly influence the photopolymerization of monomers from the first group and greatly change kinetics of those from the second. Such behavior was explained by the theory of “kinetically favorable or unfavorable monomer associations.” It was demonstrated that certain ILs accelerate the photopolymerization of the highest PEGDMs and offer access to the polymers derived from low reactive monomers. Relying on the obtained data, the attempt to predict the structure of the “best” ionic additive for the given monomer photopolymerization was performed and proved. Finally, the influence of both residual and specially added ILs quantities upon the properties of obtained polymer materials was investigated. It was revealed that ILs can physically interact with polymer networks increasing their thermal stability, plasticizing films, and blocks, imparting ionic conductivity equal up to 3.62 × 10−3 Sm/cm at 25 °C. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2388–2409, 2010
Bioinspired polymer functionalized with a diiron carbonyl model complex and its assembly onto the surface of a gold electrode via “click” chemistry
Authors: Ru Xiang , Zeng Xianghua , Li Zhimei , J. Evans David , Zhan Caixia , Tang Ying , Wang Lianjie , Liu Xiaoming
Published: April 2010

A complex pendant with two ethynyl groups, [Fe2(μ‐SCH2CCH)2(CO)6] (2), as a model of the diiron subunit of [FeFe]‐hydrogenase was polymerized and the {Fe2(CO)6} core was successfully incorporated into the polymer matrix. The polymer was characterized by a variety of spectroscopic techniques, TGA, FTIR, SEM, TEM, and NMR. The resultant polymer was immobilized via “click” chemistry using its terminal CCH bond onto the surface of a gold electrode, which was premodified with azidothiol by self‐assembled monolayer (SAM). The assembled electrode showed electrochemical responses. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2410–2417, 2010
One‐pot synthesis of well‐defined multiblock polymer: Combination of ATRP and RAFT polymerization involving cyclic trithiocarbonate
Authors: Wu Yusong , Wang Qi
Published: April 2010

Multiblock polymers were prepared by combination of ATRP (CuBr/tris[(2‐pyridyl)methyl]amine) and RAFT polymerization involving cyclic trithiocarbonate (CTTC). In the combined polymerization system, the ATRP was introduced as constant radical source, CTTC underwent ring‐opening polymerization, and the incorporated trithiocarbonate moieties derived from CTTCs performed as RAFT agent. Through the integrated process, multiblock polymers containing predictable average block number together with controlled molecular weight of the blocks were prepared by one‐pot polymerization. The average block number of polymer was controlled by concentration ratio of CTTC to alkyl halide in ARTP, and the molecular weight of block were well regulated by concentration of CTTC and monomer conversion. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2425–2429, 2010
Facile, one‐pot synthesis of aromatic diamine‐based benzoxazines and their advantages over diamines as epoxy hardeners
Authors: Chang Sheng Lung , Lin Ching Hsuan
Published: April 2010

Three aromatic diamine‐based benzoxazines were successfully prepared by a facile, clean, one‐pot procedure from 1,4‐phenylenediamine (1), 4,4′‐diaminodiphenyl ether (2), and 4,4′‐diaminodiphenyl methane (3), respectively. Their structures were confirmed by NMR spectra and single crystal diffractogram. The effect of the reactivity of diamines on the purity of the resultant benzoxazines was discussed. The resultant benzoxazines were applied as hardeners for cresol novolac epoxy (CNE). The processing window, the latent curing characteristic, and the miscibility of benzoxazine/CNE systems were discussed. Compared with diamines (1 and 3), (1 and 3)‐based benzoxazines show latent curing characteristic as epoxy hardeners, and wide processing windows can be obtained. Compared with diamine (2) which is immiscible with CNE in the molten state, (2)‐based benzoxazine shows good miscibility with CNE. Dynamic mechanical analysis shows the Tgs of the benzoxazine/CNE thermosets are as high as 242–243 °C. Thermogravimetric analysis shows the outstanding thermal stability of the resultant thermosets. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2430–2437, 2010
Overcoming the oxygen inhibition in the photopolymerization of acrylates: A study of the beneficial effect of triphenylphosphine
Authors: Belon C. , Allonas X. , Croutxé‐barghorn C. , Lalevée J.
Published: April 2010

Triphenylphosphine (TPP) was used in free‐radical UV‐curable resins to reduce oxygen inhibition effect. The relative influence of concentration, monomer viscosity, light intensity and sample thickness on TPP efficiency was investigated by real time infrared spectroscopy. It is shown that TPP is an effective oxygen scavenger. The mechanism was investigated by means of Laser Flash Photolysis. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2462–2469, 2010
Solving the loss of orthogonality during the polyaddition of α‐azide‐ω‐alkyne monomers catalyzed by Cu(PPh3)3Br: Application to the synthesis of high‐molar mass polytriazoles
Authors: Binauld Sandra , Fleury Etienne , Drockenmuller Eric
Published: April 2010

Polyaddition of an α‐azide‐ω‐alkyne monomer by Cu(PPh3)3Br catalyzed 1,3‐dipolar cycloaddition was thoroughly studied as a model system to investigate the orthogonality of this click chemistry process. Indeed, loss of chain‐end functionality and occurrence of side reactions have a tremendous impact on the molar mass of polymers obtained by step growth polymerization. Particularly, SEC, 1H, and 31P NMR experiments have highlighted the occurrence of a Staudinger side‐reaction between azide chain‐ends and PPh3 from the copper(I) catalyst that dramatically alters Mn of the resulting polytriazoles. A significant enhancement of Mn could be achieved by using an alternative catalyst and optimized experimental conditions, that is, dilution and reaction time. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2470–2476, 2010
Current treatment options in the management of severe pain
Authors: Campbell William
Published: April 2010

Opioids are the most frequently used agents for severe nociceptive pain and should not be withheld in chronic noncancer pain. Our Drug review discusses the properties and efficacy of the opioids in common use, followed by an analysis of the prescription data and sources of further information. Copyright © 2010 Wiley Interface Ltd
Avoidable prescribing errors: communication and monitoring
Authors: Avery Tony
Published: April 2010

Prescribing errors often occur against the background of overwork, stress and competing demands. In the second of two articles looking at how to reduce prescription errors in general practice, Professor Tony Avery discusses communication, medication monitoring and repeat prescribing. Copyright © 2010 Wiley Interface Ltd
Antibiotics for uncomplicated urinary tract infection in women
Authors: Thompson Sarah , Yacomeni Sarah , Townsend Robert
Published: April 2010

Most well women with uncomplicated urinary tract infection should respond to three days' treatment with a first‐line antibiotic. Our Drug review describes the properties and side‐effects of the recommended antibiotics, followed by sources of further information. Copyright © 2010 Wiley Interface Ltd
Achieving accurate blood pressure readings in primary care
Authors: Padfield Paul
Published: April 2010

Professor Padfield discusses why readings taken in the surgery will often provide an inaccurate measurement of blood pressure and how reproducible results are best achieved with patient selfmonitoring.
An analysis of transient thermal properties for high power GaN‐based laser diodes
Authors: Kim Jae Min , Kim Seungtaek , Kang Sung Bok , Kim Young Jin , Jeong Hoon , Lee Kyeongkyun , Kim Jongseok , Lee Sangdon , Suh Dongsik , Yi Jeong Hoon , Choi Yoonho , Jung Seok Gu , Noh Minsoo
Published: April 2010

Thermal properties of 405 nm GaN‐based laser diodes were investigated by employing a transient heating response method based on the temperature dependence of diode forward voltage. Thermal resistances of materials consisting of packaged laser diodes were differentiated in transient thermal response curves at a current below threshold current. With a current above threshold current, no significant change in thermal resistances and difference between junction‐up and junction‐down laser diodes was observed at pulses shorter than 3 sec. From an analysis with long current injections, thermal resistance of a packaged laser diode with a junction‐up bonding was ∼45 °C/W which was higher than that of a junction‐down bonded laser diode by ∼10 °C/W. Further analyses based on parameters obtained from voltage recovery curves indicated that the time constant for cooling is directly related to the thermal resistance and thermal capacitance of a laser diode package. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN based nanorod light emitting diodes by selective area epitaxy
Authors: Zang Keyan , Chua Soo Jin
Published: April 2010

Site‐controlled, vertically aligned gallium nitride nanorod light emitting diode (LEDs) arrays with high aspect ratio have been synthesized via catalyst‐free metalorganic chemical vapor deposition. Nanorod LEDs arrays with ∼1 μm in length and ∼200 nm in diameter were prepared on n‐type gallium nitride film on sapphire substrates using nanoporous silicon dioxide as a growth mask patterned by anodized aluminum oxide. GaN nanorod LEDs demonstrate a higher photoluminescence in intensity, compared to that of a planar GaN. This is contributed to the improvement of light extraction due to the faceted nanostructures and the improvement in crystal quality. In addition, more Indium incorporation has been demonstrated compared to the control LEDs structure. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaN surface nanostructure photodetector based on back side incidence
Authors: Zhang Jing , Naoi Yoshiki , Sakai Shiro , Fukano Atsuyuki , Tanaka Satoru
Published: April 2010

The conventional photodetector can detect the intensity of the incident light by the voltage or current, but it is not sensitive to the change of the incident angle or wavelength. A GaN‐based photodetector with nanostructure on the surface has been fabricated using nanoimprint lithography (NIL). The photovoltage between p‐ and n‐layers of the surface nanostructure photodetector took 6 or 12 periods when the incident illumination angles were changed on the back side. According to the characteristics, this type of photodetector can find out the change of the incidence angle or the change of the wavelength of the incident light. The short wave absorption disturbance can be avoided when the light illuminating based on the back side. Therefore, the stability of detection can be improved and the requirement of work environment is reduced. In addition, the generation principles of periodic photovoltage are different between the light illuminating based on the back side and the surface. Thus, the surface nanostructure photodetector can be used in wider fields. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of doping on optical properties of catalyst‐ and mask‐free grown gallium nitride nanorods
Authors: Kalden J. , Sebald K. , Kunert G. , Aschenbrenner T. , Kruse C. , Hommel D. , Gutowski J.
Published: April 2010

We present a comparison of the optical properties of Si and Mg doped GaN nanorods with respect to an undoped sample. The reference sample is characterized by a high crystalline quality as indicated by the spectral width of the dominant emission peaks being comparable for the ensemble and single nanorods as well as by the absence of the yellow photoluminescence. Even after the incorporation of n‐dopants this defect related emission band is still not detectable.The p‐doped sample shows several modifications of the spectrum. The near band edge emission is dominated by an additional band at 3.41 eV related to partial coalescence of the nanorods, while the excitonic emission is very weak. The DAP band emission is obviously evolved into a double band series with two zero‐phonon peaks at 3.26 eV and 3.18 eV indicating the involvement of two acceptor related states, and is further superimposed by a weak yellow luminescence band around 2.5 eV. These results are important as basis for applications of such nanorods as electrically driven semiconductor devices with excellent crystalline quality as well as with very high surface sensitivity, which is useful for solar cells or chemical sensors, for example. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atom probe extended to AlGaN: three‐dimensional imaging of a Mg‐doped AlGaN/GaN superlattice
Authors: Bennett Samantha E. , Clifton Peter H. , Ulfig Robert M. , Kappers Menno J. , Barnard Jonathan S. , Humphreys Colin J. , Oliver Rachel A.
Published: April 2010

Laser pulsed atom probe tomography (APT) can provide three‐dimensional chemical and spatial information in semiconductor materials, revealing buried features at the nanoscale. In this investigation, a Mg‐doped AlGaN/GaN superlattice was studied using laser pulsed APT. Such superlattices are commonly used to overcome the intrinsically low doping efficiency of Mg. Although the superlattice was nominally doped to the same level throughout, secondary ion mass spectrometry (SIMS) suggested a greater Mg content in the AlGaN layers.

The APT data provided three‐dimensional element mapping and revealed clustered Mg in both the GaN and AlGaN layers. These clusters are shown to be statistically significant when compared to a random distribution of Mg. More clusters were found in the AlGaN layers, suggesting that the presence of clusters accounts for the higher Mg level in the AlGaN layers that was suggested by SIMS. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth mechanism of nonpolar m ‐plane GaN on maskless patterned a ‐plane sapphire substrate
Authors: Kawashima Yuji , Murakami Kazuma , Abe Yuki , Okada Narihito , Tadatomo Kazuyuki
Published: April 2010

We grew nonpolar m ‐plane GaN by selective area growth and epitaxial lateral overgrowth. In this report, we investigated the growth mechanism of m ‐plane GaN on a patterned a ‐plane sapphire substrate (a ‐PSS) without an SiO2 mask. With the control of the anisotropic growth rate of c ‐plane GaN on an original a ‐plane sapphire surface and on a c ‐plane‐like sapphire sidewall in the a ‐PSS, c ‐plane GaN was grown only on the c ‐plane‐like sapphire sidewall, resulting in a pure‐oriented m ‐plane GaN layer on the a ‐PSS. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of slight misorientations of r ‐plane sapphire substrates on the growth of nonpolar a ‐plane GaN layers via HVPE
Authors: Schwaiger Stephan , Lipski Frank , Wunderer Thomas , Scholz Ferdinand
Published: April 2010

We have investigated the growth of nonpolar GaN templates by hydride vapor phase epitaxy (HVPE). This includes a systematic study of misoriented r‐plane sapphire wafers with a miscut angle up to ±1° towards the c‐axis of the crystal as starting substrates. Starting with an AlN nucleation layer approximately 3.3 μm of nonpolar a‐plane GaN are grown by metalorganic vapor phase epitaxy (MOVPE). The subsequent growth by HVPE was optimized to obtain flat and homogeneous layers with very good crystal quality. This was illustrated by very small full widths at half maximum (FWHM) of x‐ray rocking curve (XRC) measurements of less than 500 arcsec.

The surface quality was evaluated by scanning electron microscopy (SEM) and optical phase contrast microscopy showing a high number of surface defects (pits) for the samples with a high miscut towards the positive direction whereas a slight miscut of +0.5° reduces the surface roughness. Additionally, smallest XRC FWHM values have been obtained for this particular miscut. A miscut towards negative directions results in lower crystalline quality and the surfaces shows hillock‐like features. All GaN layers on misoriented substrates are tilted with respect to the substrate. Their tilt angle increases with the miscut angle. Its direction is opposed to the miscut of the sapphire. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)