bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Calculation of the Anharmonic Effect of Unimolecular Reactions of HOCO
Authors: Gu Lingzheng , Xia Wenwen , Huang Xinting , Yao Li , Shao Ying , Yang Kun
Published: May 2012

HOCO is the intermediate of the reaction H + CO2 → HO + CO. In this study, all the geometries in the collision reaction H + CO2 were optimized at MP2/6‐311++G** level with Gaussian 03 program and a potential energy surface which shows that three unimolecular reactions were in the process of HOCO → HO + CO. For the three reactions, YL method proposed by L. Yao and S. H. Lin is applied to calculate the anharmonic and harmonic total number of states, the density of states and rate constants. The anharmonic values for rate constants calculated in this study are much lower than harmonic values, which indicate that anharmonic effects are significant and can not be neglected. After convert the experimental lifetime of HOCO into rate constants, the values are close to the calculations in our research, which shows that YL method used in our study is suitable for studying the rate constants of unimolecular reaction.
Field Emission and Superhydrophobic Properties of Electrochemically Grown Gold Nanourchins
Authors: Huang Ting‐Kai , Huang Hsin‐Wei , Lee Chi‐Young , Chiu Hsin‐Tien
Published: May 2012

We demonstrate a convenient fabrication of Au nanourchins (NUs) on Si substrates via a surfactant‐assisted galvanic reduction process. This synthetic method not only grows Au NUs on Si in a one‐step process but also effectively controls the lengths of the branches on the NUs. The widths are about 100‐120 nm and the lengths can be extended from 200 nm to 5 μm by lengthening the growth time. With the advantage of a hierarchical surface structure, Au NUs exhibited excellent electron field emission (FE) performance (turn‐on voltage, 6.3 V/μm; β, 1150). In addition, the wetting behavior examination shows that the water contact angle can be as high as 158° on Au NUs after the material is treated by 1‐hexadecanethiol.
Silica gel‐Mediated Friedel‐Crafts Reaction of Indoles with Functionalized Nitroallylic Acetates via an SN1 Process
Authors: Ho Ching‐Yin , Roy Suparna , Chen Yan‐Ming , Chen Kwunmin
Published: May 2012

An environmentally friendly Friedel‐Crafts reaction was demonstrated between indoles and functionalized nitroallylic acetates in the presence of silica gel, providing the corresponding C‐3‐selective regioisomers in good to high overall chemical yields (70‐93%).
Nano‐baskets in Emulsion Liquid Membranes for Selective Extraction of Alkali Metals
Authors: Mokhtari Bahram , Pourabdollah Kobra
Published: May 2012

Nano‐assisted inclusion separation of alkali metals from basic solutions was reported by inclusion‐facilitated emulsion liquid membrane process. The novelty of this study is application of nano‐baskets of calixarene in the selective and efficient separation of alkali metals as both the carrier and the surfactant. For this aim, four derivatives of p‐tert‐calix[4]arene bearing different sulfonamide moieties were synthesized and their inclusion‐extraction parameters were optimized. The selectivity of membrane over more than ten interfering cations was examined and the results reveled that under the optimized operating condition, the degree of inclusion‐extraction of alkali metals was as high as 98‐99%.
Syntheses, Crystal Structure, and Magnetic Properties of a Self‐assembling Dicopper(II) Helicate with Novel Bipyridine Ligand
Authors: Kao Hsien‐Chang , Wang Yi‐Chun , Wang Wen‐Jwu
Published: May 2012

A novel double helical dicopper(II) complex was synthesized by reaction of a polydentate ligand L = 2,2′‐bipyridyl‐6,6′‐bis(2‐acetylpyrazinohydrazone) with copper(II) perchlorate in CH3CN. The self‐assembling process was studied by UV‐Vis spectrometric titration experiments which revealed the formation of dinuclear complexes [Cu2L2](ClO4)4. The structure of dicopper double‐helicate was confirmed by X‐ray diffractometry. Each copper(II) center occupies a distorted octahedral environment. Variable‐temperature magnetic measurements reveal weak antiferromagnetic interactions between Cu(II) ion centers with J = −0.63 cm−1.
On the Hamilton‐Waterloo Problem for Bipartite 2‐Factors
Authors: Bryant Darryn , Danziger Peter , Dean Matthew
Published: May 2012

Given two 2‐regular graphs F1 and F2, both of order n, the Hamilton‐Waterloo Problem for F1 and F2 asks for a factorization of the complete graph into α1 copies of F1, α2 copies of F2, and a 1‐factor if n is even, for all nonnegative integers α1 and α2 satisfying . We settle the Hamilton‐Waterloo Problem for all bipartite 2‐regular graphs F1 and F2 where F1 can be obtained from F2 by replacing each cycle with a bipartite 2‐regular graph of the same order.
A Phylogenetic Approach to Ontogeny and Heterochrony in the Fossil Record: Cranial Evolution and Development in Anguimorphan Lizards (Reptilia: Squamata)
Authors: Bhullar Bhart‐Anjan S.
Published: May 2012

The incorporation of ontogeny into the interpretation of the vertebrate fossil record promises major advances in palaeontology, systematics, and macroevolution. Here, a key additional component, the incorporation of phylogenetic bracketing into ontogenetic considerations, is demonstrated using cranial anatomy in anguimorphan lizards, a diverse modern clade with an extensive fossil record. The obstacles of fragmentary disarticulated fossil material and low representation in museum collections are overcome by using detailed analysis of individual elements and binning into broad ontogenetic stages, respectively. Results indicate the prevalence of classical macroevolutionary phenomena, notably heterochrony and homoplasy (convergence), throughout anguimorphan evolution. Furthermore, two problematic fossil anguimorph taxa are examined, both of which are unusually small for their clades, suggesting either immaturity or dwarfism. Using extant phylogenetic brackets of ontogenetic trajectories to distinguish between these hypotheses, it is shown that the holotype of one of these taxa is indeed a juvenile (also calling into question its taxonomy) and that the other is a dwarf. It is expected that a phylogenetic approach to ontogeny will yield similar insights across a broad range of fossil and extant organisms. J. Exp. Zool. (Mol. Dev. Evol.) 318B:521–530, 2012. © 2012 Wiley Periodicals, Inc.
ORGAN EXTRACTS AND THE DEVELOPMENT OF PSYCHIATRY: HORMONAL TREATMENTS AT THE MAUDSLEY HOSPITAL 1923–1938
Authors: EVANS BONNIE , JONES EDGAR
Published: May 2012

The use of organ extracts to treat psychiatric disorder in the interwar period is an episode in the history of psychiatry which has largely been forgotten. An analysis of case‐notes from The Maudsley Hospital from the period 1923–1938 shows that the prescription of extracts taken from animal testes, ovaries, thyroids, and other organs was widespread within this London Hospital. This article explores the way in which Maudsley doctors justified these treatments by tying together psychological theories of the unconscious with experimental data drawn from laboratory studies of human organs. It explores the logic behind these treatments and examines beliefs about their efficacy. The connection between this historical episode and current research in endocrinology and psychology is explored.
Controlling size and uniformity of molecularly imprinted nanoparticles using auxiliary template
Authors: Chen Zhiyong , Ye Lei
Published: May 2012

Molecularly imprinted nanomaterials are gaining substantial importance. As a simple and efficient synthetic method, precipitation polymerization has been used to prepare uniform molecularly imprinted microspheres for numerous template compounds. Despite of its general applicability, the difficulty of obtaining uniform particles for some difficult templates by precipitation polymerization has been reported. In this work, we attempted to produce uniform atrazine‐imprinted nanoparticles using propranolol as an auxiliary template under standard precipitation polymerization condition. When propranolol was added in the prepolymerization mixture for atrazine imprinting, it displayed a significant effect on particle size and size distribution of atrazine‐imprinted polymers. The molecular binding characteristics of the molecularly imprinted polymer (MIP) nanoparticles were found to be dependent on the relative ratios of the two templates. Under an optimal template propranolol–atrazine ratio of 1:3 mol/mol, very uniform imprinted nanoparticles (dH = 106 nm) with a polydispersity index of 0.07 were obtained. The loading of the auxiliary template (propranolol) could be reduced to as low as 5% without sacrificing the uniformity of the MIP nanoparticles. The uniform MIP nanoparticles could be easily encapsulated into polyethylene terephthalate nanofibers using a simple electrospinning technique. The composite nanofibers containing the MIP nanoparticles maintained specific molecular binding capability for both atrazine and propranolol. Copyright © 2012 John Wiley & Sons, Ltd.
An innovative approach to molecularly imprinted capillaries for polar templates by grafting polymerization
Authors: Giovannoli Cristina , Passini Cinzia , Baravalle Patrizia , Anfossi Laura , Giraudi Gianfranco , Baggiani Claudio
Published: May 2012

Molecularly imprinted polymers have been successfully used as selective stationary phases in capillary electrophoresis. Notwithstanding, this technique suffers from several drawbacks as the loss of molecular recognition properties in aqueous media and the lack of feasibility for imprinted systems directed towards highly polar templates soluble in aqueous environments only. Thus, the preparation of imprinted polymers for highly polar, water‐soluble analytes, represents a challenge. In this work, we present an innovative approach to overcome these drawbacks. It is based on a surface molecular imprinting technique that uses preformed macromonomers as both functional recognition elements and cross‐linking agents. A poly‐2‐hydroxyethyl‐co‐methacrylic acid linear polymer was grafted from the surface of silica capillaries. The grafted polymer was exhaustively esterified with methacrylic anhydride to obtain polyethylendimethacrylate‐co‐methacrylic acid linear chains. Then, as a proof of concept, an adequate amount of a very polar template like penicillin V was added in a hydro‐organic mixture, and a thin layer of imprinted polymer was obtained by cross‐linking the polymer linear chains. The binding behaviour of the imprinted and non‐imprinted capillaries was evaluated in different separation conditions in order to assess the presence of template selectivity and molecular recognition effects. The experimental results clearly show that this innovative kind of imprinted material can be easily obtained in very polar polymerization environments and that it is characterized by enhanced molecular recognition properties in aqueous buffers and good selectivity towards the template and strictly related molecules. Copyright © 2012 John Wiley & Sons, Ltd.
Responsive behavior of tumor‐marker‐imprinted hydrogels using macromolecular cross‐linkers
Authors: Miyata Takashi , Hayashi Takeshi , Kuriu Yoshiaki , Uragami Tadashi
Published: May 2012

Tumor‐marker‐imprinted hydrogels having lectin and antibody molecules as ligands for a tumor‐specific marker glycoprotein were strategically prepared by biomolecular imprinting using minute amounts of low‐molecular‐weight or high‐molecular‐weight cross‐linkers. The tumor‐marker‐imprinted hydrogels shrank gradually in response to a target glycoprotein, because their apparent cross‐linking density increased owing to simultaneous complex formation of lectin and antibody ligands with a target glycoprotein after their ligands dynamically recognized the glycoprotein. The swelling ratio of the tumor‐marker‐imprinted hydrogel using high‐molecular‐weight cross‐linker with an optimal chain length decreased more drastically than that using a low‐molecular‐weight cross‐linker, but the hydrogel using the cross‐linker with a chain that was too long did not exhibit tumor‐marker responsive behavior. This paper focuses on the effect of the molecular weight of cross‐linkers on the responsive behavior of tumor‐marker‐imprinted hydrogels having lectin and antibody molecules as ligands. The cross‐linker chain length was an important factor in determining the dynamic glycoprotein recognition and responsive behavior of the biomolecule‐imprinted hydrogels. Copyright © 2012 John Wiley & Sons, Ltd.
Image registration for targeted MRI‐guided transperineal prostate biopsy
Authors: Fedorov Andriy , Tuncali Kemal , Fennessy Fiona M. , Tokuda Junichi , Hata Nobuhiko , Wells William M. , Kikinis Ron , Tempany Clare M.
Published: May 2012

Purpose:

To develop and evaluate image registration methodology for automated re‐identification of tumor‐suspicious foci from preprocedural MR exams during MR‐guided transperineal prostate core biopsy.

Materials and Methods:

A hierarchical approach for automated registration between planning and intra‐procedural T2‐weighted prostate MRI was developed and evaluated on the images acquired during 10 consecutive MR‐guided biopsies. Registration accuracy was quantified at image‐based landmarks and by evaluating spatial overlap for the manually segmented prostate and sub‐structures. Registration reliability was evaluated by simulating initial mis‐registration and analyzing the convergence behavior. Registration precision was characterized at the planned biopsy targets.

Results:

The total computation time was compatible with a clinical setting, being at most 2 min. Deformable registration led to a significant improvement in spatial overlap of the prostate and peripheral zone contours compared with both rigid and affine registration. Average in‐slice landmark registration error was 1.3 ± 0.5 mm. Experiments simulating initial mis‐registration resulted in an estimated average capture range of 6 mm and an average in‐slice registration precision of ±0.3 mm.

Conclusion:

Our registration approach requires minimum user interaction and is compatible with the time constraints of our interventional clinical workflow. The initial evaluation shows acceptable accuracy, reliability and consistency of the method. J. Magn. Reson. Imaging 2012;36:987–992. © 2012 Wiley Periodicals, Inc.
Time‐resolved MR angiography of renal artery stenosis in a swine model at 3 Tesla using gadobutrol with digital subtraction angiography correlation
Authors: Morelli John N. , Ai Fei , Runge Val M. , Zhang Wei , Li Xiaoming , Schmitt Peter , McNeal Gary , Michaely Henrick J. , Schoenberg Stefan O. , Miller Matthew , Gerdes Clint M. , Sincleair Spencer T. , Spratt Heidi , Attenberger Ulrike I.
Published: May 2012

Purpose:

To establish the minimum dose required for detection of renal artery stenosis using high temporal resolution, contrast enhanced MR angiography (MRA) in a porcine model.

Materials and Methods:

Surgically created renal artery stenoses were imaged with 3 Tesla MR and digital subtraction angiography (DSA) in 12 swine in this IACUC approved protocol. Gadobutrol was injected intravenously at doses of 0.5, 1, 2, and 4 mL for time‐resolved MRA (1.5 × 1.5 mm2 spatial resolution). Region of interest analysis was performed together with stenosis assessment and qualitative evaluation by two blinded readers.

Results:

Mean signal to noise ratio (SNR) and contrast to noise ratio (CNR) values were statistically significantly less with the 0.5‐mL protocol (P < 0.001). There were no statistically significant differences among the other evaluated doses. Both readers found 10/12 cases with the 0.5‐mL protocol to be of inadequate diagnostic quality (κ = 1.0). All other scans were found to be adequate for diagnosis. Accuracies in distinguishing between mild/insignificant (<50%) and higher grade stenoses (>50%) were comparable among the higher‐dose protocols (sensitivities 73–93%, specificities 62–100%).

Conclusion:

Renal artery stenosis can be assessed with very low doses (∼0.025 mmol/kg bodyweight) of a high concentration, high relaxivity gadolinium chelate formulation in a swine model, results which are promising with respect to limiting exposure to gadolinium based contrast agents. J. Magn. Reson. Imaging 2012;36:704–713. © 2012 Wiley Periodicals, Inc.
Raman light scattering, infrared absorption and DSC studies of the phase transition and vibrational and reorientational dynamics of H2O ligands and ClO4– anions in [Ba(H2O)3](ClO4)2
Authors: Hetmańczyk Joanna , Hetmańczyk Łukasz , Migdał‐Mikuli Anna , Mikuli Edward , Wesełucha‐Birczyńska Aleksandra
Published: May 2012

[Ba(H2O)3](ClO4)2 between 90 and 300 K possesses two solid phases. One phase transition of the first‐order type at: = 211.3 K (on heating) and = 204.6 K (on cooling) was determined by differential scanning calorimetry. The entropy change value (ΔS ≈ 15 Jmol–1 K–1), associated with the observed phase transition, indicates a moderate degree of molecular dynamical disorder. Both, vibrational and reorientational motions of H2O ligands and ClO4– anions, in the high‐temperature and low‐temperature phases, were investigated by Fourier transform far‐infrared and middle‐infrared and Raman light scattering spectroscopies. The temperature dependences of the full‐width at half‐maximum values of the bands associated with ρw(H2O) mode, in both infrared (~570 cm–1) and Raman light scattering (~535 cm–1) spectra, suggest that the observed phase transition is not associated with a sudden change of a speed of the H2O reorientational motions. Ligands reorient fast, with correlation time of the order of several picoseconds, with a mean activation energy value Ea = 5.1 kJ mol–1 in both high and low temperature phases. On the other hand, measurements of temperature dependences of full‐width at half‐maximum values of the infrared band at ~460 cm–1, associated with δd(OClO)E mode, and Raman band at ~1105 cm–1, associated with νas(ClO)F2 mode, revealed the existence of a fast ClO4– reorientation in phase I and in phase II, with the Ea(I) and Ea(II) values equal to 8.0 and 6.5 kJ mol–1, respectively. These reorientational motions of ClO4– are slightly distorted at the TC. Fourier transform far‐infrared and middle‐infrared spectra with decreasing of temperature indicated characteristic changes at the vicinity of PT at TC, which suggested lowering of the crystal structure symmetry. All these experimental facts suggest that the discovered phase transition is associated with small change of H2O ligands and somewhat major change of ClO4– anions reorientational dynamics, and with insignificant change of the crystal structure, too. Copyright © 2012 John Wiley & Sons, Ltd.
Otolaryngologists' perceptions of odontogenic maxillary sinusitis
Authors: Longhini Anthony B. , Branstetter Barton F. , Ferguson Berrylin J.
Published: May 2012

Objectives/Hypothesis:

Odontogenic maxillary sinusitis (OMS) is a common cause of chronic rhinosinusitis (CRS); however, the condition is infrequently mentioned in recent rhinosinusitis guidelines and often overlooked as a cause of sinusitis by otolaryngologists, dentists, and radiologists. The goal of this survey is to assess otolaryngologists' perceptions of the incidence, diagnosis, and treatment of OMS.

Study Design:

Physician survey.

Methods:

Ninety‐three board certified otolaryngologists in the United States completed a 17‐question survey on etiologies of CRS, which also included questions on alternative diagnoses and radiologic findings to reduce respondent bias toward the survey's focus on odontogenic sinusitis. Results were compared between self‐reported general otolaryngologists and rhinologists.

Results:

Both groups recognized an odontogenic source as a common cause of maxillary sinusitis and reported treating an average of 2.9 patients per year with OMS who were initially misdiagnosed. Most otolaryngologists surveyed perceived radiologists to never or rarely report on dental pathology in their sinus computed tomography (CT) interpretation.

Conclusions:

Both general otolaryngologists and rhinologists recognize odontogenic sinusitis is common, although often initially misdiagnosed. With increasing awareness of OMS, we believe that otolaryngologists and radiologists will review sinus CT scans for the presence of periapical abscesses and dental pathology. The otolaryngologist should suspect an odontogenic etiology of purulent maxillary CRS in patients failing to improve with antibiotics, regardless of a negative dental workup.
Impact of sirolimus and tacrolimus on mortality and graft loss in liver transplant recipients with or without hepatitis C virus: An analysis of the Scientific Registry of Transplant Recipients Database
Authors: Watt Kymberly D. , Dierkhising Ross , Heimbach Julie K. , Charlton Michael R.
Published: May 2012

By analyzing 26,414 patients [12,589 with hepatitis C virus (HCV)] in the Scientific Registry of Transplant Recipients database, we sought to determine comparative risk factors (including primary immunosuppression) predictive of death and graft loss among patients with HCV and patients without HCV. Immunosuppression was examined at the baseline and as a time-dependent variable, and the results were stratified by the transplant center and were adjusted for variables well known to affect patient and graft survival. A multivariate analysis of patient mortality demonstrated that recipient age, donor age, hepatocellular carcinoma, diabetes, and creatinine were significantly associated with increased 3-year mortality for both groups. Tacrolimus-based immunosuppression was associated with superior survival in both groups. In contrast, the use of sirolimus was strongly associated with increased mortality in the HCV group, and cyclosporine was associated with increased mortality in the non-HCV group. Adjusting for known and unknown factors predictive of posttransplant outcomes, a propensity analysis confirmed the association of sirolimus use with an increased risk of death in HCV patients as well as the association of tacrolimus use with a decreased risk of death in all patients. In conclusion, this study suggests a novel association between sirolimus use and an increased risk of death and graft loss after liver transplantation in HCV patients that is not seen in patients without HCV. This study confirms the association of tacrolimus with superior outcomes. Sirolimus should be used sparingly in recipients with HCV infections. Liver Transpl, 2012. © 2012 AASLD.
Chemoprophylaxis with isoniazid in liver transplant recipients
Authors: Fábrega Emilio , Sampedro Blanca , Cabezas Joaquín , Casafont Fernando , Mieses Miguel Ángel , Moraleja Irene , Crespo Javier , Pons-Romero Fernando
Published: May 2012

A patient receiving a liver graft needs to be treated with immunosuppressive drugs to avoid rejection. These kinds of drugs predispose the patient to the reactivation of latent infections such as tuberculosis (TB). Therefore, it is necessary to establish treatment regimens to prevent this. We retrospectively analyzed all consecutive patients undergoing liver transplantation (LT) at our center between January 1, 2000 and December 31, 2010. Latent tuberculosis infections (LTBIs) were diagnosed with positive tuberculin skin test results. After LT, infected patients were treated with isoniazid for 6 months; the treatment began soon after transplantation, and the patients were followed until the end of the study. During this period, 53 patients had LTBI data. All these patients were treated with isoniazid after LT. The median observation period after LT was 52 months (range = 12-129 months). No cases of TB reactivation were reported during follow-up. Only 4 patients presented alterations in liver enzymes related to this treatment, and they showed clear improvement after the treatment was stopped. None of these patients showed severe graft dysfunction. In conclusion, preventive isoniazid appears to be a safe drug for use in LTBI patients after LT. The treatment may be established just after LT without important graft dysfunction or severe consequences for the patient. Liver Transpl, 2012. © 2012 AASLD.
Long‐Chain Branched Poly(Lactide)s Based on Polycondensation of AB2‐type Macromonomers
Authors: Fischer Anna M. , Wolf Florian K. , Frey Holger
Published: May 2012

A series of long‐chain branched poly(d‐/l‐lactide)s is synthesized in a two‐step protocol by (1) ring‐opening polymerization of lactide and (2) subsequent condensation of the preformed AB2 macromonomers promoted by different coupling reagents. The linear AB2 macromonomers are prepared by Sn(Oct)2‐catalyzed ROP of D‐ and L‐lactide with 2,2‐bis(hydroxymethyl)butyric acid (BHB) as an initiator. Optimization of the polymerization conditions allows for the preparation of well‐defined macromonomers (Mw/Mn = 1.09–1.30) with adjustable molecular weights (760–7200 g mol−1). The two‐step approach of the synthesis comprises as well the coupling of these AB2 macromonomers and hence allows precise control over the lactide chain length between the branching units in contrast to a random polycondensation.
Preparation of Microporous Polymers Based on 1,3,5‐Triazine Units Showing High CO2 Adsorption Capacity
Authors: Lim Ho , Cha Min Chul , Chang Ji Young
Published: May 2012

Microporous polymers based on 1,3,5‐triazine units are prepared by Friedel‐Crafts reaction of 2,4,6‐trichloro‐1,3,5‐triazine with aromatic compounds. 2,4,6‐Trichloro‐1,3,5‐triazine is polymerized with benzene, biphenyl, and terphenyl in dichloromethane in the presence of aluminum chloride. The surface areas of the polymers are in the range of 558 to 1266 m2 g−1, depending on the aromatic linker length. At ambient pressure and temperature, the polymers exhibit high CO2 uptakes of 38–51 cm3 g−1. The CO2 uptake is significantly enhanced by 70–90% for the polymers carbonized at 400 °C for 1 h and at 800 °C for an additional 1 h under nitrogen. This result suggests that rigid microporous polymers can be used as precursor polymers for the synthesis of advanced porous carbon materials without the activation process.
Visible Light‐Induced Atom Transfer Radical Polymerization
Authors: Tasdelen Mehmet Atilla , Ciftci Mustafa , Yagci Yusuf
Published: May 2012

Visible light‐induced reverse and simultaneous reverse and normal initiation (SR&NI) atom transfer radical polymerizations of vinyl monomers are examined using various dyes and type I photoinitiators. The effect of photoinitiator types on the control of molecular weight and distribution is described. In both dye and type I photoinitiator sensitized SR&NI ATRP systems, the molecular weights increase linearly with conversion. However, the experimental molecular weights are considerably higher than the theoretical values and the polymers show broad‐molecular‐weight distributions ranging from 1.28 to 1.60 in the dye‐sensitized SR&NI ATRP. However, the polymers obtained by SR&NI ATRP using type I photoinitiator system had molecular weight values close to the theoretical ones and very narrow‐molecular‐weight distributions ranging from 1.11–1.18.
Inhibition of epstein‐barr virus reactivation in nasopharyngeal carcinoma cells by dietary sulforaphane
Authors: Wu Chung‐Chun , Chuang Hsin‐Ying , Lin Chao‐Yi , Chen Yen‐Ju , Tsai Wan‐Hua , Fang Chih‐Yeu , Huang Sheng‐Yen , Chuang Fu‐Yang , Lin Su‐Fang , Chang Yao , Chen Jen‐Yang
Published: May 2012

Epstein‐Barr virus (EBV) has been associated with several human malignancies including nasopharyngeal carcinoma (NPC). Reactivation of latent EBV has been considered to contribute to the carcingenesis of NPC. Blocking the EBV lytic cycle has been shown effective in the treatment of EBV‐associated diseases. We have searched for natural dietary compounds inhibiting EBV reactivation in NPC cells. Among them, sulforaphane (SFN) was found to be effective in the inhibition of EBV reactivation in latent EBV‐positive NPC cells, NA and HA. SFN is a histone deacetylase (HDAC) inhibitor and has been recognized as an antioxidant and antitumor compound for chemoprevention. However, its antiviral effect is less well elucidated. In this study, after determination of the cytotocixity of SFN on various epithelial cells, we showed that SFN treatment inhibits EBV reactivation, rather than induction, by detection of EBV lytic gene expression in EBV‐positive NPC cells. We also determined that the number of cells supporting the EBV lytic cycle is decreased using immunofluorescence and flow cytometric analysis. Moreover, we have found that this inhibitory effect decreases virus production. To elucidate the inhibitory mechanism of SFN on the EBV lytic cycle, luciferase reporter assays were carried out on the Zta and Rta promoters. The results show that SFN inhibits transactivation activity of the EBV immediate‐early gene Rta but not Zta. Together, our results suggest that SFN has the capability to inhibit EBV lytic cycle and the potential to be taken as a dietary compound for prevention of EBV reactivation. © 2012 Wiley Periodicals, Inc.
Retracted: Measuring the impact of commercialism, community expectation and consensus in the development of ‘common’ and ‘agreed’ values from the perspective of a member‐based medical organisation
Authors: Grebe Sasha Karl
Published: May 2012

Purpose

The purpose of this paper is to examine the experience of a not‐for‐profit (NFP) organisation, the Royal Australasian College of Physicians, as an example of an NFP organisation seeking to develop an ‘agreed’ and ‘common’ set of core corporate/organisational values.

Design/methodology/approach

The main approach is examine the values development process of the College against the organisational values measures of commercialism, community expectation and consensus and what impact these had on the process.

Findings

The finding of the research collected during the development process and the evaluation of the final set of values against the measures highlights the unique challenges that NFP organisations can experience in developing ‘common’ and ‘agreed’ core corporate organisational values.

Research limitations/implications

The research includes qualitative and quantitative research using interviews and surveys of the members of the organisation (the Fellows), the employees of the College and a sample of key external stakeholders.

Practical implications

The case study of the College provides guidance for organisations seeking to undertake a values development process, and the research contributes to the theory of internal communication and organisational development.

Originality/value

This paper uses the unique insights of a case study to provide practical guidance for practitioners on organisational values and their development, especially in the NFP sector. Copyright © 2012 John Wiley & Sons, Ltd.
Survey‐Based Measurement of Public Management and Policy Networks
Authors: Henry Adam Douglas , Lubell Mark , McCoy Michael
Published: May 2012

Networks have become a central concept in the policy and public management literature; however, theoretical development is hindered by a lack of attention to the empirical properties of network measurement methods. This paper compares three survey‐based methods for measuring organizational networks: the roster, the free‐recall name generator, and a hybrid name generator that combines these two classic approaches. Results indicate that the roster and free‐recall name generator methods both suffer from important limitations. The roster method tends to measure many linkages among a limited set of network actors, whereas the name generator tends to measure fewer linkages among a larger set of network actors. Using survey data on policy networks within California regional planning processes (N = 752), we find that the hybrid method strikes an effective balance between these techniques. The hybrid approach performs well in terms of identifying a large number of network actors and interconnections between them. Although no survey‐based measurement technique is perfect, this study suggests that the hybrid name generator is an excellent alternative for the measurement of complex networks with large or shifting boundaries that encompass a diverse set of actors.
Leukocytes from wheezing infants release lower amounts of IL‐12 and IFN‐γ compared to non‐wheezing infants
Authors: Falcai Angela , Pereira Paulo Vítor Soeiro , Kubo Christina Arslanian , Rullo Vera , Errante Paolo Rugero , Solé Dirceu , Condino‐Neto Antonio
Published: May 2012

Objective

This study investigated environmental endotoxin exposure during early life, sensitization to aeroallergens, the production of cytokines by LPS‐stimulated leukocytes, and the development of a wheezing phenotype in a prospective cohort of infants with high risk of developing allergic diseases.

Materials and Methods

Eighty‐four infants were followed from birth until 30 months of age. We assessed endotoxin concentration in house dust of their homes during the first 6 months of life. At age 30 months they were clinically evaluated to determine the development of wheezing and other clinical events, were skin prick tested, and had blood samples collected for the evaluation of cytokine release by LPS‐stimulated peripheral blood mononuclear cells (PBMC).

Results

The level of endotoxin exposure during early life was not associated with development of a wheezing phenotype. On the other hand a higher incidence of respiratory infections occurred among recurrent wheezing (RW) infants. PBMC from RW children exposed to higher levels of environmental endotoxin (above 50 EU/mg) released less Interleukin (IL)‐12p70 and IFN‐γ compared to the non‐RW group. TNF‐α, IL‐10, IL‐4, IL‐5, and IL17 production by LPS‐stimulated PBMC from RW and non‐RW children was equivalent in both groups of environmental endotoxin exposure.

Conclusion

In this prospective cohort of infants with high risk of developing allergic diseases we observed that RW and non‐RW children were exposed to similar levels of endotoxin early in life. LPS‐stimulated PBMC from RW infants exposed to higher levels of endotoxin released significantly less IL‐12 and IFN‐γ compared to non‐RW infants. Pediatr Pulmonol. 2012. 47:1054–1060. © 2012 Wiley Periodicals, Inc.
Analysis of serum and plasma identifies differences in molecular coverage, measurement variability, and candidate biomarker selection
Authors: Alsaif Murtada , Guest Paul C. , Schwarz Emanuel , Reif Andreas , Kittel‐Schneider Sarah , Spain Michael , Rahmoune Hassan , Bahn Sabine
Published: May 2012

Purpose

To compare the use of serum and plasma in multiplex immunoassay analyses of 190 proteins and small molecules, and associated molecular pathways. We also tested whether differences between these biofluids can influence the identification of potential biomarkers in a preliminary study comparing bipolar disorder patients with controls.

Experimental design

Using multiplexed immunoassay analyses, we compared the measurement levels and interindividual variation of 190 proteins and small molecules between serum and plasma collected from 21 healthy individuals. We exemplify how this can impact on the outcome of biomarker discovery studies using a case study of 24 patients with bipolar disorder.

Results

Detection of analytes was similar for serum and plasma, although there were marked differences in measurement variability for 29 proteins and cortisol. When considering the disease cohort we identified six proteins that changed significantly in serum and ten in plasma with an overlap of two proteins.

Conclusions and clinical relevance

In spite of the similarities of coverage on a multiplexed platform for serum and plasma, there were important differences in interindividual variability, which can have significant impact on identifications made in biomarker studies.
Precursor ion exclusion for enhanced identification of plasma biomarkers
Authors: Wu Wells W. , Shen Rong‐Fong , Park Sung‐Soo , Martin Bronwen , Maudsley Stuart
Published: May 2012

Purpose

Our study aims to establish a plasma biomarker analysis workflow, with fewer fractionation steps, for enhanced identification of plasma biomarkers by precursor ion exclusion (PIE).

Experimental design

Plasma samples were depleted for highly abundant proteins, then further fractionated by molecular weight (MW), before trypsinization for LTQ‐Orbitrap mass analysis. Data‐dependent acquisition (DDA) was used for baseline analysis. PIE involves the re‐injection of samples with exclusion of the previously identified peptides. We compared analyses using multiple PIE iterations, compared to DDA, for plasma interrogation

Results

A higher percentage of unique plasma peptides was identified with PIE, compared to DDA. The first PIE iteration reveals an increase of 75–112% more peptides than the DDA method alone. PIE can interrogate complex plasma samples with the percentage of peptides identified successively increasing with even ≥4 iterations. The total number of peptides identified increases rapidly across the first three PIE iterations and then continues more slowly up to nine iterations.

Conclusions and clinical relevance

Iterative injections with PIE resulted in many more peptide identifications in plasma samples of varying degrees of complexity, compared to re‐injections using similar DDA parameters. PIE methods may therefore expand our ability to recover plasma peptides for plasma biomarker discovery.
Angiotensin‐(1‐7) reduces proliferation and angiogenesis of human prostate cancer xenografts with a decrease in angiogenic factors and an increase in sFlt‐1
Authors: Krishnan Bhavani , Torti Frank M. , Gallagher Patricia E. , Tallant E. Ann
Published: May 2012

BACKGROUND

Prostate cancer is the most frequently diagnosed malignancy and the second‐leading cause of cancer death in men. The purpose of this study was to determine the anti‐proliferative and anti‐angiogenic efficacy of angiotensin‐(1‐7) [Ang‐(1‐7)], an endogenous peptide hormone, in human prostate cancer xenografts.

METHODS

Human LNCaP prostate cancer cells were injected into the flank of athymic mice and tumors were treated with Ang‐(1‐7) for 54 days. Tumor growth and angiogenesis were determined by immunohistochemistry and western blot hybridization.

RESULTS

Ang‐(1‐7) markedly reduced the volume and wet weight of LNCaP xenograft tumors. Histological analysis of tumor sections from saline‐treated mice showed increased Ki67 immunoreactivity and enhanced phosphorylation of the MAP kinases ERK1/2 compared to tumors from Ang‐(1‐7)‐treated mice, suggesting that the heptapeptide reduces cell proliferation. Intratumoral vessel density was decreased in Ang‐(1‐7)‐treated mice with an associated reduction in vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), suggesting that the heptapeptide attenuates vascularization by reducing angiogenic factors. Ang‐(1‐7) administration markedly increased the soluble fraction of VEGF receptor 1 (sFlt‐1), with a concomitant reduction in VEGF receptors 1 and 2. sFlt‐1 serves as a decoy receptor that traps VEGF and PlGF, making the ligands unavailable to membrane‐bound VEGF receptors and preventing activation of pro‐angiogenic signaling.

CONCLUSIONS

The decrease in PlGF and VEGF coupled with the increase in sFlt‐1 suggests that Ang‐(1‐7) may serve as a novel anti‐angiogenic therapy for prostate cancer. Further, the pleiotropic mechanisms of action by Ang‐(1‐7) may limit angiogenic resistance that occurs with VEGF inhibitors or receptor blockers. Prostate 73: 60–70, 2013. © 2012 Wiley Periodicals, Inc.
Preliminary investigations on auxetic structures based on recycled rubber
Authors: Silva Thaís A. A. , Panzera Túlio H. , Brandão Lincoln C. , Lauro Carlos H. , Boba Katarzyna , Scarpa Fabrizio
Published: May 2012

The growing demand for tyres in transport industry provides a negative impact on the environment, due to the problems related to recycling and disposal of the rubber waste. However, adding waste tyres as a dispersive phase in polymeric composites has shown high toughness and moderate increase of mechanical strength within the composites. In this work, we investigate the use of recycled rubber core to manufacture auxetic (re‐entrant) honeycomb structures. The re‐entarnt honeycombs produced are evaluated using finite element analysis and tensile in‐plane to assess the sensitivity of the mechanical properties versus the cell geometric parameters. A full factorial design (33) was performed to investigate the effects of the factors width (10 and 20 mm), thickness (2 and 4 mm) and angle (−10 and −20°) on Poisson's ratio of honeycomb structures. The results give further evidence that the Poisson's ratio is affected not only by individual factors but also by interaction originated by the other geometric parameters.
Low energy electron beam induced damage on gallium nitride based materials
Authors: Nykänen Henri , Mattila Päivi , Suihkonen Sami , Riikonen Juha , Sopanen Markku
Published: May 2012

We present our studies on low energy electron beam induced damage to gallium nitride semiconductor material. We have observed a clear reduction in InGaN single quantum well and bulk GaN band‐to‐band emission intensity induced by low energy electron beam irradiation. The dose and energy of the e‐beam were 0 ‐ 500 μC/cm2 and of 5 ‐ 20 keV, respectively. We attributed the damage mechanism to electron beam induced defect electromigration. The electromigration is caused by a localized electric field generated by high local current density. However, further studies are needed to confirm the damage mechanism. These results should be considered in electron beam related fabrication, characterization and usage of GaN‐based materials (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear properties of the dipole layer in MOS‐based hydrogen detectors
Authors: Šrobár Fedor , Procházková Olga
Published: May 2012

Nonlinear dielectric properties of the dipole layer formed at the catalytic metal/insulator interface of MOS‐based hydrogen sensors are investigated. A two‐valley potential profile is used to model electronic states in adsorbed H atoms polarized by difference in electron affinities between metal and oxide and to derive constitutive equation expressing dielectric polarization P as a function of applied electric field E. An up‐to‐fourth order expansion of this dependence is given, using modified dielectric susceptibilities. Application of superposed static and alternating fields leads to a significant third harmonic generation. The expressions derived could help to design experiments yielding values of parameters characterizing the dipole layer. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Comparative optical studies of InGaAs/GaAs quantum wells grown by MBE on (100) and (311)A GaAs planes
Authors: Khatab A. , Shafi M. , Mari R. H. , Aziz M. , Henini M. , Patriarche G. , Troadec D. , Sadeghi M. , Wang S.
Published: May 2012

The temperature dependence of the optical properties of InGaAs/GaAs double quantum wells (QWs) grown by molecular beam epitaxy (MBE) on (100) and (311)A GaAs substrates has been studied by photoluminescence (PL). It is found that for an excitation of 50 mW, the PL quenching for (100) and (311)A QWs occurs at 220 K and 300 K, respectively. This suggests that the high index plane (311)A has superior structural properties and less non‐radiative defect centers than the conventional (100) plane. The better optical quality of the QWs grown on (311)A is also confirmed by the narrowing of the full width at half‐maximum (FWHM) of the PL emission: 10 nm for (311)A and 20 nm for (100). From these findings it is expected that optical devices grown on (311)A GaAs planes should have better performances than those grown on conventional (100) orientation. We have also carried out a systematic study to investigate the effect of post‐growth thermal annealing on the optical quality of the QWs. We observed a substantial improvement of the PL efficiency with annealing temperatures in the range 500‐700 °C for all samples. However, this PL enhancement is accompanied by a blueshift. These energy shifts can be explained by interdiffusion or intermixing of In and Ga atoms at the interfaces between the QWs and the barriers. A noticeable narrowing of the PL linewidth with higher annealing temperatures could be explained by a homogenisation of the quantum well interfaces (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Binary anodic oxides for memristor‐type nonvolatile memory
Authors: Kundozerova Tatyana V. , Stefanovich Genrikch B. , Grishin Alexander M.
Published: May 2012

The temperature dependence of the optical properties of InGaAs/GaAs double quantum wells (QWs) grown by molecular beam epitaxy (MBE) on (100) and (311)A GaAs substrates has been studied by photoluminescence (PL). It is found that for an excitation of 50 mW, the PL quenching for (100) and (311)A QWs occurs at 220 K and 300 K, respectively. This suggests that the high index plane (311)A has superior structural properties and less non‐radiative defect centers than the conventional (100) plane. The better optical quality of the QWs grown on (311)A is also confirmed by the narrowing of the full width at half‐maximum (FWHM) of the PL emission: 10 nm for (311)A and 20 nm for (100). From these findings it is expected that optical devices grown on (311)A GaAs planes should have better performances than those grown on conventional (100) orientation. We have also carried out a systematic study to investigate the effect of post‐growth thermal annealing on the optical quality of the QWs. We observed a substantial improvement of the PL efficiency with annealing temperatures in the range 500‐700 °C for all samples. However, this PL enhancement is accompanied by a blueshift. These energy shifts can be explained by interdiffusion or intermixing of In and Ga atoms at the interfaces between the QWs and the barriers. A noticeable narrowing of the PL linewidth with higher annealing temperatures could be explained by a homogenisation of the quantum well interfaces (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
New type of 5–22 THz radiation sources based on semiconductor resonant reflectors
Authors: Požela Juras , Širmulis Edmundas , Požela Karolis , Šilėnas Aldis , Jucienė Vida
Published: May 2012

In polar semiconductors, the lattice dielectric function varies resonantly in the radiation frequency range ωT < ω < ωL, where ωT and ωL are the transverse and longitudinal optical phonon frequencies, respectively. The resonant reflectance spectra in the 5–22 THz range from polar semiconductors InSb, AlAs, InP, GaAs, GaN and GaAs/AlGaAs heterostructures are investigated experimentally. The semiconductor resonant reflectors are proposed, and a capability of separating a narrow spectral band from the heated‐body emission spectrum was realized. A new type of the continuous wave THz radiation source operational in the 5–22 THz range is proposed. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of epitaxial layer thickness on the deep level defects in MBE grown n‐type Al0.33Ga0.67As
Authors: Mari Riaz H. , Aziz M. , Shafi M. , Khatab A. , Taylor D. , Henini M.
Published: May 2012

The effect of the epitaxial layer thickness on the deep level defects in MBE grown n‐Al0.33Ga0.67As is investigated for the first time using current‐voltage‐temperature (I‐V‐T), deep level transient spectroscopy (DLTS) and Laplace DLTS techniques. The epitaxial layer thickness is found to have profound effects on the room temperature I‐V characteristics, the number of defects detected by DLTS and their concentrations. In this investigation we compare n‐Al0.33Ga0.67As samples having epitaxial layer thicknesses of 2 µm and 1.5 µm. Our results reveal that by increasing the layer thickness (1) the reverse current increases; (2) the number of electrically active deep defects increases from two to six; (3) the concentration of the traps increases.

The I‐V‐T and DLTS measurements carried out from 20 K to 300 K show that there is a dominant trap with an activation energy of ∼0.48 eV in both samples but with different concentrations (8.59 × 1014cm‐3 and 1.48 × 1014 cm‐3 for 2 µm and 1.5 µm samples, respectively). The reduction in the reverse current is directly related to the number of defects and their concentration. Our findings have important implications on the performances of electronic and optoelectronic devices. An attempt to explain the effect of the layer thickness on the deep traps in n‐Al0.33Ga0.67As will be given (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)