bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of ofloxacin enantioseparation by ligand exchange chromatography
Authors: Tian Minglei , Yan Hongyuan , Row Kyung Ho
Published: January 2009

BACKGROUND: There is much interest in the recognition and determination the two ofloxacin enantiomers, not only from the point of view of investigating the pharmacokinetics of the enantiomers in vitro but also in the design and development of new chiral pharmaceutics.

RESULTS: Chiral separation was performed on a C18 column, in which the mobile phase consisted of a methanol–water solution (containing different concentrations of L‐phenylalanine and copper sulfate) and its flow rate was set at 0.7 mL min−1. The effect of different kinds and concentration of ligands, bivalent copper ion, organic modifier, ionic liquid modifier, pH of mobile phase, and temperature on enantioseparation were evaluated and the results show that the enantioselectivity was strongly affected by the pH and ligand concentration of the mobile phase. Under optimal conditions, baseline separation of the two enantiomers was obtained with a resolution of 4.69 in less than 40 min.

CONCLUSION: The mechanism of chiral discrimination is based on the stabilities of the copper(II) binary complexes and their ternary diastereomeric complexes with amino acids formed in solution and stationary phase. The proposed method could be used for the quality evaluation of ofloxacin enantiomers. Copyright © 2009 Society of Chemical Industry
Comment on M. Guillot‐Delost et al. (2008;10:834‐846): Clinical‐grade preparation of human natural regulatory T cells encoding the thymidine kinase suicide gene as a safety gene
Authors: Battaglia Manuela , Strauss Laura , Roncarolo Maria‐Grazia
Published: January 2009

This Letter to the Editor has a published Response, which can be viewed using the link below.

Response to Comment
6‐[(2‐Iminopyrrolidinyl)methyl]‐5‐[125I]iodouracil as a potential thymidine phosphorylase‐targeted radiopharmaceutical: synthesis and preliminary biological evaluation
Authors: Mukai Takahiro , Taketomi Masato , Tashiro Masaaki , Yamamoto Fumihiko , Maeda Minoru
Published: January 2009

Thymidine phosphorylase (TP) is expressed at higher levels in many types of malignant tumors than in adjacent nonneoplastic tissues. The aim of this study was to develop a radiolabeled TP inhibitor, 6‐[(2‐iminopyrrolidinyl)methyl]‐5‐[125I]iodouracil ([125I]1) as a TP‐targeted radiopharmaceutical. No‐carrier‐added [125I]1 was synthesized by halogen exchange of the corresponding bromide (2). After purification by reverse‐phase HPLC, [125I]1 showed a radiochemical purity of over 97%. When administered to normal mice, [125I]1 showed a rapid clearance from the blood and a low accumulation in the thyroid and stomach, indicating good in vivo stability against deiodination. By coinjection of unlabeled 1, the uptakes in the TP‐expressing normal tissues, small intestine and liver were significantly reduced, suggesting TP‐specific modes of accumulation of [125I]1. These findings suggest that [125I]1 possesses the required properties for in vivo imaging of TP activity. Copyright © 2009 John Wiley & Sons, Ltd.
Rhodium‐mediated [11C]carbonylation: a library of N‐phenyl‐N′‐{4‐(4‐quinolyloxy)‐phenyl}‐[11C]‐urea derivatives as potential PET angiogenic probes
Authors: Ilovich Ohad , Åberg Ola , Långström Bengt , Mishani Eyal
Published: January 2009

As part of our ongoing investigation into the imaging of angiogenic processes, a small library of eight vascular endothelial growth factor receptor‐2 (VEGFR‐2)/platelet‐derived growth factor receptor β dual inhibitors based on the N‐phenyl‐N′‐4‐(4‐quinolyloxy)‐phenyl‐urea was labelled with 11C (β+, t1/2=20.4 min) in the urea carbonyl position via rhodium‐mediated carbonylative cross‐coupling of an aryl azide and different anilines. The decay‐corrected radiochemical yields of the isolated products were in the range of 38–81% calculated from [11C]carbon monoxide. Starting with 10.7±0.5 GBq of [11C]carbon monoxide, 1‐[4‐(6,7‐dimethoxy‐quinolin‐4‐yloxy)‐3‐fluoro‐phenyl]‐3‐(4‐fluoro‐phenyl)‐[11C]‐urea (2.1 GBq) was isolated after total reaction time of 45 min with a specific activity of 92±4 GBq µmol−1. Copyright © 2009 John Wiley & Sons, Ltd.
Organization of nucleobase‐functionalized β‐peptides investigated by soft electrospray ionization mass spectrometry
Authors: Diezemann Nicola , Weigang Linda M. M. , Chakraborty Pradip , Frauendorf Holm , Letzel Thomas , Diederichsen Ulf
Published: January 2009

The development and validation of analytical methods is a key to succeed in investigating noncovalent interactions between biomolecules or between small molecules and biomolecules. Electrospray ionization mass spectrometry (ESI‐MS) was applied with a Fourier transform ion cyclotron resonance mass spectrometer (FTICR‐MS) as well as a quadrupole/time‐of‐flight tandem mass spectrometer (QqToF‐MS) for a systematic investigation of noncovalent complexes based on nucleobase pairing in an artificial and noncharged backbone topology. Synthetical β‐peptide helices covalently modified with nucleobases were organized by recognition of a sequence of four nucleobases. Specific duplexes of β‐peptide helices were obtained on the basis of hydrogen bonding base pair complementarity. Oligomer interactions were detected with defined stoichiometry and sensitivity for the respective duplex stability. FTICR‐MS and QqToF‐MS were used equally well to indicate double strand stabilities in agreement with the dissociation data determined by UV spectroscopy. Furthermore, the dissociation energies of gas phase ions of the noncovalent complexes were analyzed with collision induced dissociation (CID)‐MS/MS and infrared multiphoton dissociation (IRMPD)‐MS/MS. The CID conditions turned out to be too harsh for a differentiation of the duplex stabilities, whereas IRMPD might be developed as a technique to detect even small interaction energy differences. Copyright © 2009 John Wiley & Sons, Ltd.
The laryngeal chemoreflex: An evaluation of the normoxic response
Authors: Heman‐Ackah Yolanda D. , Pernell Kerri J. , Goding George S.
Published: January 2009

Objectives:

The laryngeal chemoreflex is a reflexive central apnea, bradycardia, and cardiovascular collapse that occurs in young, maturing mammals in response to exposure of the laryngeal mucosa to acidic and/or organic stimuli. The severity of the laryngeal chemoreflex varies within a species from one animal to another, and in some animals, the response can be fatal. This study seeks to identify those factors that contribute to fatal laryngeal chemoreflex responses when the larynx is stimulated under normoxic conditions, and to define how the normoxic response differs from the hypoxic laryngeal chemoreflex response.

Study Design:

This is a prospective study evaluating the response to laryngeal stimulation of 80 newborn piglets.

Methods:

The laryngeal chemoreflex response was elicited from 67 piglets under normoxic conditions. The data were collected from a combination of three separate experimental protocols, each of which included inducing the laryngeal chemoreflex under normoxic conditions as the first step. The physiologic response was recorded with a combination of arterial blood gas, pulse oximetry, blood pressure, and continuous cardiac monitoring.

Results:

Resumption of respirations occurred when the pCO2 rose by a mean of 8.34 (Standard Deviation [SD] = 4.8) mmHg, regardless of response severity (ANOVA, P > .05). Moderate (requiring supplemental O2 for recovery) and profound (fatal) responders had a significantly higher prestimulation pCO2 (95% confidence interval [CI] 39.8–44.8 mmHg and 40.5–46.4 mmHg, respectively) than did mild (recovery without assistance) responders (95% CI 36.8–40.8 mmHg, ANOVA, P < .05). Baseline pH was statistically significantly different as a function of response severity (95% CI profound: 7.29–7.37, moderate: 7.33–7.38, and mild 7.36–7.39, P < .05).

Conclusions:

Accumulation of arterial CO2 is associated with resumption of respirations during the normoxic laryngeal chemoreflex. The combination of an elevated prestimulation pCO2 and a low prestimulation pH predicts a profound laryngeal chemoreflex response under normoxic conditions. Laryngoscope, 119:370–379, 2009
Low‐cost dual‐action aural foreign‐body extractor
Authors: Dwivedi Raghav C. , Dwivedi Ravi C. , Bhatia Naresh , Rhys‐Evans Peter H.
Published: January 2009

Adequate visualization, appropriate equipment, a cooperative patient, and a skilled physician are keys to successful foreign body removal. The first attempt at removal is critical because success rates markedly decrease after the first failed attempt. Laryngoscope, 119:351–354, 2009
Randomized, double blind, placebo controlled trial on the safety and efficacy of continuous intratympanic dexamethasone delivered via a round window catheter for severe to profound sudden idiopathic sensorineural hearing loss after failure of systemic therapy
Authors: Plontke Stefan K. , Löwenheim Hubert , Mertens Jürgen , Engel Corinna , Meisner Christoph , Weidner Andy , Zimmermann Rainer , Preyer Serena , Koitschev Assen , Zenner Hans‐Peter
Published: January 2009

Objectives:

To study the safety and efficacy of continuous intratympanic dexamethasone‐phosphate (Dex‐P) for severe to profound sudden idiopathic sensorineural hearing (ISSHL) or sudden idiopathic anacusis after failure of systemic therapy.

Study Design:

Randomized, double‐blind, placebo controlled multicenter trial.

Methods:

Patients with ISSHL and insufficient recovery (mean 4PTA = 97 dB HL) after systemic high dose glucocorticoid therapy received either Dex‐P (4mg/ml) or placebo (NaCl 0.9%) continuously applied for 14 days into the round window niche via a temporarily implanted catheter. For ethical reasons, intratympanic treatment was continued with Dex‐P in all patients for another 14 days after the placebo‐controlled study period. According to a two‐step adaptive study design an interim analysis was performed after inclusion of 23 patients.

Results:

Intention‐to‐treat analysis for the primary outcome criterion (4PTA: 0.5‐3kHz) during the placebo controlled study period (14 days) showed an average hearing improvement in the treatment group of 13.9 dB (SD: 21.3) and in the placebo group of 5.4 dB (SD: 10.4). This difference in hearing improvement between the two groups (mean: 8.4 dB, SD: 17.0, 95% CI: −7.1–24.1) was statistically not significant (p = .26). Of the secondary outcome parameters, the largest benefit of local salvage therapy was found for maximum speech discrimination with an improvement of 24.4% (SD: 32.0) in the treatment and 4.5% (SD: 7.6) in the placebo group (p = 0.07). After a 3 month follow‐up period (i.e. after all patients received intratympanic Dex‐P) hearing improvement in the two groups was very similar. No serious adverse events were observed. Sample size calculation after the interim analysis resulted in stopping of the trial.

Conclusions:

The tendency toward better hearing improvement in the treatment group, the rather conservative inclusion criteria, the limited placebo‐controlled observation period and the absence of serious adverse events supports further investigation local inner ear drug delivery as a first or second line treatment option for ISSHL. Laryngoscope, 119:359–369, 2009
Bisphosphonate‐related osteonecrosis of the jaw and its associated risk factors: A belgian case series
Authors: Saussez Sven , Javadian Rokneddine , Hupin Chloé , Magremanne Michèle , Chantrain Gilbert , Loeb Isabelle , Decaestecker Christine
Published: January 2009

Objectives:

Bisphosphonate‐related osteonecrosis of the jaw (BROJ) is a serious oral complication of bisphosphonate (BP) treatment involving the exposure of necrotic maxillary or mandibular bone. Our purpose is to describe the clinical presentation of 34 cases of BROJ and to identify potential risk factors.

Study Design:

A retrospective study was performed in four Belgian institutions.

Methods:

Complete medical histories were recorded and analyzed. These data include age, gender, initial disease requiring BP, type and duration of BP treatment, symptomatology and location of BROJ, prior dental procedures, treatment of the BROJ and treatment outcome, and radiographic, histological, and microbiological data.

Results:

Bisphosphonates (BP) were used in the management of disseminated cancers in 30 patients (88.5% of total studied), while four patients received BP due to osteoporosis (11.5%). The most frequently used BP was zoledronic acid in 29 patients (83%). Microbiological data obtained in 25 patients demonstrated that 72% of these patients were infected or colonized by an actinomyces. Eight of the 14 patients (57%) who received only medical treatment were cured. Of the 20 patients who underwent surgical treatments, only four were completely cured (20%). BROJ lesions smaller than 1 cm are associated with better prognosis in terms of treatment outcomes (P = .0009). Local treatments combined with long‐term antibiotics are also correlated with better prognosis (P = .02).

Conclusions:

Lesions smaller than 1 cm and lesions that were subject to medical treatments are associated with a better outcome. Surgical treatments appear to be non‐beneficial for BROJ. Laryngoscope, 119:323–329, 2009
Percutaneous tracheotomy in otolaryngology–head and neck surgery residency training programs
Authors: Goldenberg David , Park Sunny S. , Carr Michele
Published: January 2009

Objectives:

Percutaneous tracheotomy (PT) has been garnering attention in otolaryngology–head and neck surgery (OTO–HNS) community for many years. This procedure is used routinely by a variety of surgical disciplines; yet its use remains controversial especially in OTO–HNS. The purpose of this study is to understand the current practices pertaining to PT in OTO–HNS training programs.

Study Design:

Multi‐institution physician survey.

Methods:

A survey of 102 American OTO–HNS residency program directors.

Results:

The response rate was 80%. 29% of programs perform PT on a regular basis. Ciaglia Blue Rhino method was used by all respondents who could identify the method used. Simultaneous video bronchoscopy was always used by 91% of those who performed PT. Among respondents in programs where PT was not done regularly, 18% felt that it was the method of choice for selected patients; among those in programs where PT was done regularly, 72% felt that it was the method of choice. 64% of respondents indicated that other hospital services regularly performed PT in their institution, and this was evenly split between trauma, general surgery, pulmonology and intensive care unit (ICU). There was no significant difference in this regard between respondents from hospitals that did or did not do PT. 71% of OTO–HNS graduates are not trained in PT.

Conclusions:

Only 29% of otolaryngology residency programs in the U.S. perform PT regularly. This study objectively shows that this is a highly polarized subject amongst OTO–HNS but apparently not in medicine in general. Further study is needed to understand the reason for this controversy. Laryngoscope, 119:289–292, 2009
Dural arteriovenous fistula: Diagnosis, treatment, and outcomes
Authors: Cohen Samuel D. , Goins Jeanne L. , Butler Susan G. , Morris P. Pearse , Browne J. Dale
Published: January 2009

Objectives:

The objective of this study is to determine the sensitivity of computed tomography angiography (CTA) and magnetic resonance angiography (MRA) compared to the gold standard, conventional carotid angiography, in the diagnosis of a dural arteriovenous fistula (DAVF). Further objectives include identifying outcomes of treatment and complications as a function of pretreatment radiologic classification.

Study Design:

This is a retrospective review of adults diagnosed with a DAVF between 1990 and 2006.

Methods:

Data collected included age, gender, presenting clinical symptoms, diagnostic imaging modalities (conventional angiography, CTA, and/or MRA), interventions (self‐compression of artery, embolization, craniotomy, or a combination of these), results (symptoms resolved, improved, or same), and complications (embolic or surgical). All DAVFs were classified according to the Cognard classification.

Results:

There were a total of 46 patients with 51 fistulas, of whom 42 patients (46 fistulas) had complete follow‐up data. Using conventional angiography as the gold standard, CTA had a sensitivity of 15.4%, whereas MRA had a sensitivity of 50%. Embolization (either single or multiple treatments) was the most common treatment, being done in 36/46 (78%) fistulas. Presenting symptoms were resolved or improved in 45/46 fistulas (97.8%) regardless of treatment or Cognard classification. There were complications in 12/46 (26%) patients, most of which were transient and resolved without permanent sequelae.

Conclusions:

A DAVF is a vascular lesion that is best diagnosed with conventional angiography, but can often be found with MRA. Treatment with endovascular embolization is effective and has few significant complications. Laryngoscope, 119:293–297, 2009
Microdebrider‐assisted versus radiofrequency‐assisted inferior turbinoplasty
Authors: Liu Chia‐Min , Tan Ching‐Ding , Lee Fei‐Peng , Lin Kai‐Nan , Huang Hung‐Meng
Published: January 2009

Objectives:

The study aimed to evaluate the long‐term efficacy of microdebrider‐assisted inferior turbinoplasty (MAIT) compared to radiofrequency‐assisted inferior turbinoplasty (RAIT) for hypertrophic inferior turbinates.

Study Design:

Surgical outcomes were evaluated using the visual analogue scale, anterior rhinomanometry, and saccharin test results.

Methods:

From January 2001 to December 2006 inclusively, 120 patients with persistent allergic rhinitis, chronic nasal obstruction, and hypertrophic inferior turbinates were enrolled in this study, randomly classified, and underwent either MAIT (n = 60) or RAIT. Ten patients who did not have any nasal discomfort served as normal controls. Assessments (visual analogue scale, anterior rhinomanometry, and saccharin test) were conducted prior to surgery and 6 months, 1, 2, and 3 years subsequent to surgery.

Results:

Compared to preoperative values, the symptom scores (nasal obstruction, sneezing, rhinorrhea, and snoring), mean total nasal resistance, and mean saccharin transit time all improved significantly at 6 months, 1, 2, and 3 years after surgery in MAIT group (P < .05 for all). The same holds true for the RAIT group from 6 months up to 1 year (P < .05 for all), but no improvements from 2 to 3 years after were noted. The parameters between the two groups did not significantly differ 6 months after surgery, but was noted after 1 to 3 years (P < .05 for all).

Conclusion:

MAIT is more effective than RAIT at relieving nasal symptoms and decreasing total nasal resistance and saccharin transit time 1 to 3 years postoperatively in patients with persistent allergic rhinitis and who have substantial nasal obstruction. Laryngoscope, 119:414–418, 2009
Defining the nasopalatine line: The limit for endonasal surgery of the spine
Authors: de Almeida John R. , Zanation Adam M. , Snyderman Carl H. , Carrau Ricardo L. , Prevedello Daniel M. , Gardner Paul A. , Kassam Amin B.
Published: January 2009

Objectives:

The expanded endoscopic endonasal approach (EEA) to the odontoid process is performed for decompression of the brainstem and to access tumors at the foramen magnum. Caudal exposure is limited by the nasal bones anteriorly and the hard palate posteriorly. We define the line connecting these two points as the nasopalatine line (NPL) and the nasopalatine angle (NPA) as the angle between the nasopalatine line and the plane of the hard palate.

Study Design:

This study was a retrospective cohort study.

Methods:

Pre and post‐operative computed tomographic (CT) scans of 17 patients who underwent transodontoid EEA were reviewed. The position of the odontoid and the inferior extent of the tumor and surgical dissection were compared to the NPL. Factors affecting the posterior projection of the NPL, including basilar invagination and head position, were examined.

Results:

The mean NPA was 27.1° (range 21–31°). The NPL intersects the spinal column at 8.9 mm (range −9.0–8.7 mm) above the base of the C2 body. The base of the odontoid process and the inferior extent of surgical dissection were always above this line. Both basilar invagination and head position affect the relative position of the NPL. Patients with basilar invagination demonstrated a significantly lower posterior projection of the NPL than those without (P < .01). Maximal cervical flexion afforded more caudal exposure than cervical extension.

Conclusions:

The NPL accurately predicts the most inferior extent of surgical dissection. Further caudal dissection may require the use of angled instruments or a transoral approach. Laryngoscope, 119:239–244, 2009
Bile acids identified in middle ear effusions of children with otitis media with effusion
Authors: Klokkenburg Joost J.C. , Hoeve Hans L.J. , Francke Jan , Wieringa Marjan H. , Borgstein Johannes , Feenstra Louw
Published: January 2009

Objectives/Hypothesis:

Several studies have shown the presence of pepsin in the middle ear effusions of children with otitis media with effusion (OME). When gastric reflux is the cause, other noxious reflux products might be present. We therefore investigated the presence of bile acids in the middle ear effusions of children with OME.

Study Design:

We evaluated 38 children (63 samples of middle ear secretions (ME samples)) in a prospective study at a tertiary care children's hospital.

Methods:

ME samples were collected from children with OME during ventilation tube insertion. Most ME samples were diluted with albumin. The presence of bile acids was measured with the 3α‐hydroxy steroid dehydrogenase enzymatic method. A ME sample was considered positive when it contained at least 5 μmol/l bile acids, independent of dilution. Blood samples were taken simultaneously as a reference to determine bile acids serum levels.

Results:

We found bile acids in 32 % (20/63) of all ME samples and in 42% (16/38) of all children. Bile acids concentrations of 12 well‐soluble ME samples ranged from 5.9–40.9 μmol/L and were 3.1–19.7 times higher than the serum concentrations. In 4 of the corresponding serums, no bile acids were measurable at all.

Conclusions:

Bile acids are present in a number of the ME samples of children with OME. Because of dilution, it is possible that more ears contain bile acids. Bile acids are known to be noxious to mucosal cells at a higher (pH) than pepsin and, therefore, might play a role in the pathology of OME. Laryngoscope, 119:396–400, 2009
13C CP MAS NMR of halogenated (Cl, Br, I) pharmaceuticals at ultrahigh magnetic fields
Authors: Terskikh Victor V. , Lang Stephen J. , Gordon Peter G. , Enright Gary D. , Ripmeester John A.
Published: January 2009

This work reports significantly improved spectral resolution of 13C CP MAS NMR spectra of chlorinated, brominated and iodinated solid organic compounds when such spectra are recorded at ultrahigh magnetic field strengths. The cause of this is the residual dipolar coupling between carbon atoms and quadrupolar halogen nuclides (chlorine‐35/37, bromine‐79/81 or iodine‐127), an effect inversely proportional to the magnetic field strength which declines in importance markedly at 21.1 T as compared to lower fields. In favorable cases, the fine structure observed can be used for spectral assignment, e.g. for Cl‐substituted aromatics where the substituted carbon as well as the ortho‐carbons show distinct doublets. The experimental results presented are supported by theoretical modeling and calculations. The improved spectral resolution in the studied systems and similar halogenated materials will be of particular interest and importance for polymorph identification, drug discovery and quality control in the pharmaceutical industry. Copyright © 2009 John Wiley & Sons, Ltd.
Personality and career success: Concurrent and longitudinal relations
Authors: Sutin Angelina R. , Costa Paul T. , Miech Richard , Eaton William W.
Published: January 2009

The present research addresses the dynamic transaction between extrinsic (occupational prestige, income) and intrinsic (job satisfaction) career success and the Five‐Factor Model (FFM) of personality. Participants (N = 731) completed a comprehensive measure of personality and reported their job title, annual income and job satisfaction; a subset of these participants (n = 302) provided the same information approximately 10 years later. Measured concurrently, emotionally stable and conscientious participants reported higher incomes and job satisfaction. Longitudinal analyses revealed that, among younger participants, higher income at baseline predicted decreases in Neuroticism and baseline Extraversion predicted increases in income across the 10 years. Results suggest that the mutual influence of career success and personality is limited to income and occurs early in the career. Copyright © 2009 John Wiley & Sons, Ltd.
How to find what's in a name: Scrutinizing the optimality of five scoring algorithms for the name‐letter task
Authors: LeBel Etienne P. , Gawronski Bertram
Published: January 2009

Although the name‐letter task (NLT) has become an increasingly popular technique to measure implicit self‐esteem (ISE), researchers have relied on different algorithms to compute NLT scores and the psychometric properties of these differently computed scores have never been thoroughly investigated. Based on 18 independent samples, including 2690 participants, the current research examined the optimality of five scoring algorithms based on the following criteria: reliability; variability in reliability estimates across samples; types of systematic error variance controlled for; systematic production of outliers and shape of the distribution of scores. Overall, an ipsatized version of the original algorithm exhibited the most optimal psychometric properties, which is recommended for future research using the NLT. Copyright © 2009 John Wiley & Sons, Ltd.
Influence of solvent quality on successive solution fractionation (SSF) efficiency of high‐density polyethylene
Authors: Stéphenne Vincent , Bailly Christian , Berghmans Hugo , Daoust Daniel , Godard Pierre
Published: January 2009

BACKGROUND: Preparative successive solution fractionation (SSF) is a powerful technique for obtaining narrow‐dispersity fractions on a multi‐gram scale of high‐density polyethylene (HDPE). In a previous paper, the operative separation mechanisms during SSF of a broad HDPE in cyclohexanone were studied. Two mechanisms, and not only one as expected from the literature, contribute to the separation of HDPE molecules according to their molar mass (MM). The very low MM chains are separated by a solid–liquid (S–L) mechanism, while the longer chains are isolated by a liquid–liquid (L–L) phase separation. In the present paper, the influence of a poorer solvent, diphenyl ether, is reported.

RESULTS: It is shown that the relative importance of the S–L mechanism with respect to the L–L one is altered by the use of this solvent. The L–L temperature range is increased in diphenyl ether while the S–L transition temperature remains unchanged. Consequently, the SSF efficiency is improved. Large amounts (on a gram scale) of narrow‐dispersity fractions are isolated, mainly by the L–L mechanism. Polydispersities are about 1.5 (compared to 2.0 for cyclohexanone) and a broader MM range of closer molar mass distribution fractions is available.

CONCLUSION: This work demonstrates that the use of diphenyl ether, a poorer solvent than cyclohexanone (always used as SSF solvent for polyethylene in the literature), leads to an improvement of SSF efficiency for an essentially linear HDPE. The differences of behaviour during the separation with cyclohexanone or diphenyl ether are explained by the establishment of a phase diagram. Copyright © 2009 Society of Chemical Industry
Fluorine‐ and siloxane‐containing polymers for supercritical carbon dioxide lithography
Authors: Sha Jing , Ober Christopher K
Published: January 2009

Supercritical carbon dioxide has emerged as an environmentally friendly solvent for processing selected polymer and molecular glass photoresists at very high resolution. This article describes recent successes in the lithographic patterning of fluorine‐ and siloxane‐containing polymers using supercritical carbon dioxide as a developer solvent. Copyright © 2009 Society of Chemical Industry
The synthesis of organometallic rod–coil block copolymers from polysilanes
Authors: Hiorns Roger C , Holder Simon J
Published: January 2009

This mini‐review gives a short summery of the chain‐end chemistry of polysilanes, notably that leading to block copolymers. The anionic polymerisations of cyclotetrasilanes or ‘masked’ disilenes naturally lend themselves to the formation of polysilane‐containing copolymers. A more robust, if less controlled, method results from the Wurtz‐type reductive coupling reaction that yields polysilanes with silyl chloride chain‐ends which are extremely sensitive to nucleophilic substitution. These may be used with appropriately functionalised polymers (such as polyisoprene or poly(ethylene oxide)) to prepare multiblock copolymers, or with functionalised groups designed as initiating centres for subsequent controlled reversible deactivation radical polymerisations (such as atom transfer radical polymerisation). Copyright © 2009 Society of Chemical Industry
Genetic and biochemical analysis of a laboratory‐selected spirodiclofen‐resistant strain of Tetranychus urticae Koch (Acari: Tetranychidae)
Authors: Van Pottelberge Steven , Van Leeuwen Thomas , Khajehali Jahangir , Tirry Luc
Published: January 2009

BACKGROUND: Spirodiclofen is a selective, non‐systemic acaricide from the new chemical class of tetronic acid derivatives. In order to develop strategies to minimise resistance in the field, a laboratory‐selected spirodiclofen‐resistant strain of the two‐spotted spider mite, Tetranychus urticae Koch, was used to determine genetic, toxicological, biochemical and cross‐resistance data.

RESULTS: Selecting for spirodiclofen resistance in the laboratory yielded a strain (SR‐VP) with a resistance ratio of 274, determined on the larval stage. The egg stage remained far more susceptible. No cross‐resistance was found against other established acaricides, except for spiromesifen. Based on synergist experiments and enzyme assays, it appeared that especially P450 monooxygenases, but also esterases and glutathione‐S‐transferases, could be involved in the metabolic detoxification of spirodiclofen. Genetic analysis showed that the resistance is inherited as an intermediate trait under control of more than one gene.

CONCLUSIONS: Resistance to spirodiclofen exceeded by far the recommended field rate. A good acaricide resistance management programme is necessary to prevent fast resistance build‐up in the field. Spirodiclofen can be used in alternation with most established acaricides, except for other tetronic acid derivatives. Without selection pressure, resistance tends to be unstable and can decrease in the presence of susceptible individuals owing to the intermediate, polygenic inheritance mode. Copyright © 2009 Society of Chemical Industry
Detection of ppm‐order hydrogen gas by Pd/AlGaN/GaN high electron mobility transistor‐based sensors
Authors: Nakamura Seiji , Takahashi Noriyuki , Okumura Tsugunori
Published: January 2009

The hydrogen sensing properties of AlGaN/GaN high electron mobility transistors with Pd gate electrodes are demonstrated under various hydrogen concentrations. Remarkable current variation, as high as 1.7 mA at the drain‐source voltage of 4 V and gate‐source voltage of 0 V, was observed at 140 °C even at 1 part per million (ppm) hydrogen concentration. The logarithmic relation between the detection current variation and the hydrogen concentration was observed. By using the least‐square fit to the experimental data, the reliable lower detection value of hydrogen concentration for the present device can be estimated to be about 0.45 ppm, i.e., 450 parts per billion (ppb) as a current variation of 1 mA. In addition, the turn‐on and turn‐off transient times have been estimated to be approximately 23 and 33 seconds at 160 °C, respectively, in the case of the 100 ppm hydrogen gas. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Status of high efficiency and high power ThinGaN®‐LED development
Authors: Baur Johannes , Baumann Frank , Peter Matthias , Engl Karl , Zehnder Ulrich , Off Juergen , Kuemmler Volker , Kirsch Markus , Strauss Joerg , Wirth Ralph , Streubel Klaus , Hahn Berthold
Published: January 2009

In this paper we report on the improvement of ThinGaN®‐PowerLED structures in epitaxy, chip design, phosphor efficiency and package design. The brightness of these devices increased by a factor of 4 over the last 4 years. We demonstrate 604 mW blue (440 nm; 3,24 V; 53% WPE), 129 lm cool‐white light (5000 K; 3,25 V, 113 lm/W) and 88.2 lm warm‐white (3200 K; 74.4 lm/W; CRI 80) emission for 1mm2‐chip Dragon power LEDs at 350 mA operation. In an advanced device we realized values of 643 mW blue (440 nm; 3,24 V; 350 mA; WPE: 57%) and 155 lm white (5000 K, 350 mA, 3,24 V, 136 lm/W) emission. To our knowledge these are the highest brightness and efficacy values reported in literature. Also at 1.4 A operation current the performance of these multi quantum well epitaxy based structures is superior to the values reported for double heterostructure epitaxy based structures. By combination of phosphor converted white and red 1 mm2 chip LEDs we realized a 3000 K warm white emitting device with 100 lm/W, CRI 90 and 850 lm emission. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electrical properties of Mg‐doped GaN and AlxGa1–xN
Authors: Komissarova Tatiana A. , Jmerik Valentin N. , Mizerov Andrey M. , Shmidt Nataliya M. , Ber Boris Ya. , Kasantsev Dmitry Yu. , Ivanov Sergey V.
Published: January 2009

We report on plasma‐assisted molecular beam epitaxy (PA MBE) growth of Mg‐doped GaN and AlxGa1–xN (x = 0.15 and 0.42) layers on c‐sapphire (N‐polarity) and studies of their electrical properties as functions of growth temperature, Mg flux and alloy composition. P‐type conductivity was examined to follow the general trends defined for MOVPE and Ga‐polar GaN layers grown by metal‐organic vapor phase epitaxy and MBE. The achieved hole concentration in the GaN:Mg layers measured by Hall effect and C‐V is in the range of (0.3 – 2)×1018 cm–3 at Mg BEP changing within (2 – 7)×10–9 Torr. Hall hole concentration p = 4×1017 cm–3 and mobility μ = 1.4 cm2/Vs at 250 K have been measured for the first time in AlxGa1–xN with x > 0.4 grown by PA MBE. Acceptor activation energies for GaN:Mg and Al0.15Ga0.85N:Mg epilayers were determined from temperature dependences of resistivity at T ≥ 300 K to be EA ∼ 100 meV and 220 meV, respectively. Hopping mechanism of conductivity was confirmed for AlxGa1–xN:Mg layers studied at T ≤ 300 K. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effective heat dissipation and higher light extraction efficiency of GaN vertical light emitting diodes for solid state lighting applications
Authors: Chu Chen‐Fu , Fan Feng‐Hsu , Cheng Chao‐Chen , Liu Wen‐Huan , Chu Jiunn‐Yi , Cheng Hao‐Chun , Lin Chia‐Feng , Chen Kuei‐Ting , Tran Chuong Anh , Doan Trung
Published: January 2009

Vertical sapphire‐free GaN based LEDs (VLEDs) on metal have shown much better performance and prove to deliver an efficiency much higher than most conventional light source. In this paper we show that in addition to many advantages of VLEDs over conventional LEDs in terms of better current spreading, low operation voltage, higher drive current density, faster heat dissipation, VLEDs also enables top surface engineering for efficient light extraction to further light output. High power white LED having efficiency of 110 lumen/watt was achieved through a combination of surface engineering and optimization of the n‐GaN layer thickness underneath the corrugated pyramids surface. The low operation junction temperature of VLEDs demonstrates excellent heat dissipation capabilities. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Studies towards freestanding GaN in hydride vapor phase epitaxy by in‐situ etching of a sacrificial ZnO buffer layer
Authors: Lipskil Frank , Thapa Sarad B. , Hertkorn Joachim , Wunderer Thomas , Schwaiger Stephan , Scholz Ferdinand , Feneberg Martin , Wiedenmann Michael , Thonke Klaus , Hochmuth Holger , Lorenz Michael , Grundmann Marius
Published: January 2009

By in‐situ etching of a ZnO buffer layer freestanding GaN layers were prepared by hydride vapor phase epitaxy (HVPE). For the template growth, single crystalline ZnO buffer layers, grown by pulsed laser deposition on sapphire, were used. They were overgrown with a thin GaN layer by a multilayer growth using metal organic vapor phase epitaxy (MOVPE).

The removal of the ZnO buffer during the HVPE growth allowed the fabrication of strain‐free freestanding GaNlayers with a full width‐half‐maximum of the donor bound exciton (D0X) of 2.3 meV at a position of 3.47 eV in low temperature (15 K) photoluminescence (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vacancy defects probed with positron annihilation spectroscopy in In‐polar InN grown by plasma‐assisted molecular beam epitaxy: Effects of growth conditions
Authors: Reurings Floris , Tuomisto Filip , Gallinat Chad S. , Koblmüller Gregor , Speck James S.
Published: January 2009

In this work we have applied positron annihilation spectroscopy to study the effect of different growth conditions, on vacancy formation in In‐polar InN grown by plasma‐assisted molecular beam epitaxy (PA‐MBE). We find that the stoichiometric conditions have little effect on the In vacancy concentration in the thin films. On the other hand, the optimization of the GaN buffer used for initiating InN growth leads to a lower In vacancy concentration. This indicates that the structural quality of the material dictates the In vacancy formation in InN, while the thermodynamic and kinetic effects have a less important role, contrary to what is observed in, e.g., GaN. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Extremely high efficiency 280 nm‐band emission from quaternary InAlGaN quantum wells realized by controlling Si‐doped layers
Authors: Fujikawa Sachie , Hirayama Hideki , Takano Takayoshi , Tsubaki Kenji
Published: January 2009

Quaternary InAlGaN alloys are attracting much attention as candidate materials for realizing deep ultraviolet (DUV) light‐emitting diodes (LEDs). In this study, we investigated the effect of Si‐doping in the quaternary InAlGaN quantum well (QW) emitting region for obtaining a high efficiency DUV emission. Quaternary InAlGaN multi (M)‐QWs with Si‐doped InAlGaN buffer and barrier layers were grown on sapphire (0001) / AlN / AlGaN template by low‐pressure metal‐organic chemical‐vapor deposition (LP‐MOCVD). We found that the surface roughness of InAlGaN layer was significantly improved by introducing the light‐doping of Si. The oxygen impurity concentration in the quaternary InAlGaN layer was significantly reduced by the small amount of Si‐doping. We also revealed that the emission efficiency of the InAlGaN QW was markedly improved by inserting thin (3‐nm‐thick) undoped InAlGaN interlayer between n‐AlGaN buffer and n‐InAlGaN layers. At last, we demonstrated extremely high intensity PL emission from 280 nm‐band InAlGaN QWs at room temperature (RT). The ratio of the integrated intensity of the RT‐PL against the 77 K‐PL was 86%. This result suggests that the internal quantum efficiency (IQE) of the InAlGaN‐QW is considerably high. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
1‐2 ML thick InN‐based quantum wells with InGaN barriers for blue‐green light emitters
Authors: Yuki Akihiko , Watanabe Hiroshi , Che Song‐Bek , Ishitani Yoshihiro , Yoshikawa Akihiko
Published: January 2009

An LED structure with a 1‐2 monolayer (ML) thick InN quantum well (QW) with InGaN barrier grown by radio‐frequency plasma assisted molecular beam epitaxy (rf‐MBE) is proposed for a new active layer of blue‐green light emitters. Compared with previously reported 1‐2 ML thick InN/GaN QWs, extended emission wavelength up to pure green region (∼530 nm) is expected for these QWs with InGaN barriers. It is found that for the InN/InGaN QW structure, in which the InGaN layer is used as a barrier instead of GaN, very thin InN well layers are basically formed in the same manner as the InN/GaN QWs. In photoluminescence spectra at 15 K, emission peak wavelengths are observed from 412 nm to 480 nm when In contents in InGaN barriers are changed from 0.005 to 0.14. The emission wavelength is longer than that of 1‐2ML thick InN/GaN QWs (380nm‐430nm), and green emission can be obtained by further increase of In content in InGaN barrier to more than 0.2. The 1‐2 ML thick InN/In0.08Ga0.92N(10nm) 5‐QW LED structure was successfully fabricated and bright EL emission was observed at 419 nm, which is longer than that of a 1‐2 ML InN/GaN 5‐QW LED. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Astragalus membranaceus prevents daunorubicin‐induced apoptosis of cultured neonatal cardiomyocytes: role of free radical effect of Astragalus membranaceus on daunorubicin cardiotoxicity
Authors: Luo ZhongGuang , Zhong Lu , Han XiaoFeng , Wang HaiRong , Zhong JiHua , Xuan ZhengHua
Published: January 2009

Anthracyclines are antitumor antibiotics with significant activity against solid and hematologic malignancies. One problem preventing more widespread use has been the development of cardiotoxicity. To determine whether antioxidant agents can reduce the cardiotoxicity of anthracyclines, a herb Astragalus membranaceus was introduced, which has been widely used for the treatment of cardiovascular diseases in China and was confirmed to be an effective antioxidant agent recently. Pre‐treatment with Astragalus membranaceus significantly attenuated the daunorubicin‐induced increases of reactive oxygen species (p < 0.001), apoptosis (p < 0.05) and the secretions of LDH (p < 0.01) in cultured neonatal cardiomyocytes. Astragalus membranaceus also raised the EC50 of daunorubicin 1.24‐fold. Compared with Astragalus membranaceus, N‐acetyl‐l‐cysteine had similar effects on daunorubicin‐induced cell injury, however, superoxide dismutase reduced reactive oxygen species without attenuating apoptosis. The subcellular distribution of DNR was similar to the distribution of MitoTracker Red 580 in mitochondria, which was mainly in the cytoplasm around the nuclear membrane in cultured neonatal cardiomyocytes. In conclusion, the results suggested that Astragalus membranaceus is potentially protective against daunorubicin cardiotoxicity by decreasing free radical release and apoptosis in cultured neonatal cardiomyocytes. The main subcellular distribution of daunorubicin may be in the mitochondria. Copyright © 2009 John Wiley & Sons, Ltd.
Richardson–Lucy deconvolution of reflection electron energy loss spectra
Authors: Hummel Stefan , Gross Alexander , Werner Wolfgang S. M.
Published: January 2009

A procedure for deconvolving the energy spread introduced by the primary beam and the analyzer in a reflection electron energy loss spectrum (REELS) has been developed. The procedure is based on the Richardson–Lucy (RL) algorithm. The approach has been successfully tested on experimental spectra by comparison with spectra with an inherent high‐energy resolution. As a typical result, it was found that the effective energy resolution of spectra with a full width half maximum (FWHM) of the elastic peak of ∼1.5 eV in the raw experimental data can be reduced to ∼0.7 eV in the deconvoluted spectra. Copyright © 2009 John Wiley & Sons, Ltd.
A new estimate of family disease history providing improved prediction of disease risks
Authors: Feng Rui , McClure Leslie A. , Tiwari Hemant K. , Howard George
Published: January 2009

Complex diseases often aggregate within families and using the history of family members' disease can potentially increase the accuracy of the risk assessment and allow clinicians to better target on high risk individuals. However, available family risk scores do not reflect the age of disease onset, gender and family structures simultaneously. In this paper, we propose an alternative approach for a family risk score, the stratified log‐rank family score (SLFS), which incorporates the age of disease onset of family members, gender differences and the relationship among family members. Via simulation, we demonstrate that the new SLFS is more closely associated with the true family risk for the disease and more robust to family sizes than two existing methods. We apply our proposed method and the two existing methods to a study of stroke and heart disease. The results show that assessing family history can improve the prediction of disease risks and the SLFS has strongest positive associations with both myocardial infarction and stroke. Copyright © 2009 John Wiley & Sons, Ltd.
Diversification strategy, capital structure, and the Asian financial crisis (1997–1998): evidence from Singapore firms
Authors: Ngah‐Kiing Lim Elizabeth , Das Shobha S. , Das Amit
Published: January 2009

We use agency theory to predict the influence of related and unrelated product diversification on a firm's level of debt financing. Further, we argue that the link between diversification and capital structure is moderated by the environment in which firms operate. Using SAS PROC MIXED, we fit a mixed‐effects model to our unique six‐year longitudinal dataset (1995–2000) of 245 publicly listed Singapore firms. Our data spans the period of the Asian Financial Crisis (1997–1998). We find that firms pursuing unrelated product diversification take on less debt financing in stable environments, but more debt financing in dynamic environments. Using longitudinal structural equation modeling, we find a reciprocal relationship between a firm's product diversification strategy and its debt financing level. Copyright © 2009 John Wiley & Sons, Ltd.
Validation of GCC optimizers through trace generation
Authors: Kanade Aditya , Sanyal Amitabha , Khedker Uday P.
Published: January 2009

The translation validation approach involves establishing semantics preservation of individual compilations. In this paper, we present a novel framework for translation validation of optimizers. We identify a comprehensive set of primitive program transformations that are commonly used in many optimizations. For each primitive, we define soundness conditions that guarantee that the transformation is semantics preserving. This framework of transformations and soundness conditions is independent of any particular compiler implementation and is formalized in PVS. An optimizer is instrumented to generate the trace of an optimization run in terms of the predefined transformation primitives. The validation succeeds if (1) the trace conforms to the optimization and (2) the soundness conditions of the individual transformations in the trace are satisfied. The first step eliminates the need to trust the instrumentation. The soundness conditions are defined in a temporal logic and therefore the second step involves model checking. Thus the scheme is completely automatable. We have applied this approach to several intraprocedural optimizations of RTL intermediate code in GNU Compiler Collection (GCC) v4.1.0, namely, loop invariant code motion, partial redundancy elimination, lazy code motion, code hoisting, and copy and constant propagation for sample programs written in a subset of the C language. The validation does not require information about program analyses performed by GCC. Therefore even though the GCC code base is quite large and complex, instrumentation could be achieved easily. The framework requires an estimated 21 lines of instrumentation code and 140 lines of PVS specifications for every 1000 lines of the GCC code considered for validation. Copyright © 2009 John Wiley & Sons, Ltd.