bluuebunny/crossref_metadata_2025 huggingface dataset:
Salinity source‐induced changes in yield, mineral composition, phenolic acids and flavonoids in leaves of artichoke and cardoon grown in floating system
Authors: Borgognone Daniela , Cardarelli Mariateresa , Rea Elvira , Lucini Luigi , Colla Giuseppe
Published: October 2013

BACKGROUND

Leaves of artichoke (Cynara cardunculus L. subsp. scolymus (L.) Hegi) and cardoon (Cynara cardunculus L. var. altilis DC) are traditionally used as herbal medicine. Moderate salt stress could enhance antioxidant activity and phytochemicals in leaves. The aim of this study was to evaluate the effect of chloride salts (NaCl, KCl and CaCl2) on biomass production, mineral composition, phenolic and flavonoid contents and antioxidant activity in leaves of artichoke and cardoon grown in a floating system.

RESULTS

In both crops, NaCl and KCl treatments reduced biomass production, while similar values were recorded in CaCl2 and control treatments. In both crops, KCl treatment enhanced total phenolic and flavonoid contents, antioxidant activity and target polyphenols in leaves harvested at 48, 82 and 105 days after sowing (DAS), while leaf quality was improved by NaCl and CaCl2 treatments only at 82 and 105 DAS. Irrespective of salinity, leaves of cardoon had higher total phenolic and flavonoid contents, antioxidant activity and target polyphenols than those of artichoke.

CONCLUSION

The results showed that application of KCl can be considered an effective way to produce high‐quality leaves of artichoke and cardoon during the whole cropping cycle, although resulting in a 30% reduction in plant biomass. © 2013 Society of Chemical Industry
Simultaneous isocratic separation of phenolic acids and flavonoids using micellar liquid chromatography
Authors: Hadjmohammadi Mohammad Reza , Nazari S. Saman S. J.
Published: October 2013

The simultaneous isocratic separation of a mixture of five phenolic acids and four flavonoids (two important groups of natural polyphenolic compounds with very different polarities) was investigated in three different RPLC modes using a hydro‐organic mobile phase, and mobile phases containing SDS at concentrations below and above the critical micellar concentration (submicellar LC and micellar LC (MLC), respectively). In the hydro‐organic mode, methanol and acetonitrile; in the submicellar mode methanol; and in the micellar mode, methanol and 1‐propanol were examined individually as organic modifiers. Regarding the other modes, MLC provided more appropriate resolutions and analysis time and was preferred for the separation of the selected compounds. Optimization of separation in MLC was performed using an interpretative approach for each alcohol. In this way, the retention of phenolic acids and flavonoids were modeled using the retention factors obtained from five different mobile phases, then the Pareto optimality method was applied to find the best compatibility between analysis time and quality of separation. The results of this study showed some promising advantages of MLC for the simultaneous separation of phenolic acids and flavonoids, including low consumption of organic solvent, good resolution, short analysis time, and no requirement of gradient elution.
Management specificities of congenital laryngeal stenosis
Authors: Blanchard Marion , Leboulanger Nicolas , Thierry Briac , Blancal Jean‐Philippe , Glynn Fergal , Denoyelle Françoise , Garabedian Erea Noël
Published: October 2013

Objectives/Hypothesis

This study aimed to report our experience in the management of congenital laryngeal stenosis and to compare our series and results to published data in the literature.

Study Design

Retrospective case series. Tertiary referral center for rare pediatric head and neck malformations.

Methods

Medical charts of patients diagnosed with congenital laryngeal stenosis in our institution were reviewed over a 15‐year period, from 1996 to 2011. Surgical treatment consisted of an endoscopic procedure, open laryngeal surgery (OLS), or a combination of both.

Results

Sixteen patients met the inclusion criteria for the study and were divided in two groups: the endoscopic laryngoplasty (EL) group, with patients who underwent the endoscopic procedure as first‐line treatment, and the OLS group, whose patients underwent open laryngoplasty with cartilage graft as first‐line treatment. Each group contained eight patients with grade II to IV congenital stenosis. All patients, except one in the EL group, achieved a good result (<50% residual stenosis) at the end of the follow‐up.

Conclusions

This case series suggests that EL, with incision of the subglottic laryngeal cartilages with cold steel instruments and balloon dilation, is a safe and effective treatment for congenital laryngeal stenosis grade II to IV. This procedure could be considered as an alternative option to OLS, even as a first‐line procedure. An endoscopic procedure does not preclude the possibility for an open laryngeal procedure in case of failure. A prolonged follow‐up is mandatory.

Level of Evidence

4. Laryngoscope, 124:1013–1018, 2014
Laryngeal electromyography as a diagnostic tool for Parkinson's disease
Authors: Zarzur Ana P. , de Campos Duprat André , Cataldo Berenice O. , Ciampi Daniel , Fonoff Erich
Published: October 2013

Objectives/Hypothesis

To study the laryngeal electromyography pattern in patients with Parkinson's disease (PD) and vocal complaints at different stages of the disease.

Study Design

Cross‐sectional cohort study.

Methods

Ninety‐four adults with PD and vocal complaints at different stages of the disease (according to the Hoehn and Yahr scale) underwent laryngeal electromyography.

Results

Tremors were not detected on laryngeal electromyography of the cricothyroid and thyroarytenoid muscles even in patients with clinical tremor. Laryngeal electromyography hypercontractility during voice rest was the typical result observed in 91.5% of patients regardless of disease severity. Gender and age of subjects did not correlate with laryngeal electromyography results. Patients with PD presented spontaneous intrinsic laryngeal muscle activity during voice rest, regardless of disease severity.

Conclusions

This study was significant because it reported on the use of laryngeal electromyography in a large number of patients with PD and vocal complaints grouped according to PD severity. The patterns observed suggest that laryngeal electromyography is a valuable diagnostic tool for PD even at early phases of the disease.

Level of Evidence

4. Laryngoscope, 124:725–729, 2014
Incidence and long-term risk of de novo malignancies after liver transplantation with implications for prevention and detection
Authors: Schrem Harald , Kurok Marlene , Kaltenborn Alexander , Vogel Arndt , Walter Ulla , Zachau Lea , Manns Michael P. , Klempnauer Jürgen , Kleine Moritz
Published: October 2013

The goal of this study was the characterization of long-term cancer risks after liver transplantation (LT) with implications for prevention and detection. Site-specific cancer incidence rates and characteristics were compared retrospectively for 2000 LT patients from a single institution (January 1, 1983 to December 31, 2010) and the general German population with standardized incidence ratios (SIRs); the total follow-up at December 31, 2011 was 14,490 person-years. The cancer incidence rates for the LT recipients were almost twice as high as those for the age- and sex-matched general population (SIR = 1.94, 95% CI = 1.63-2.31). Significantly increased SIRs were observed for vulvar carcinoma (SIR = 23.80), posttransplant lymphoproliferative disorder/non-Hodgkin lymphoma (SIR = 10.95), renal cell carcinoma (SIR = 2.65), lung cancer (SIR = 1.85), and colorectal cancer (SIR = 1.41). The mean time between transplantation and diagnosis was 6.8 years. The mean age at the time of diagnosis was significantly lower for the cohort versus the general population with similar malignancies [50 years (both sexes) versus 69 and 68 years (males and females), P ≤ 0.006]. Tumors were diagnosed at more advanced stages, and there was a trend of higher grading, which suggested more aggressive tumor growth. Tumor treatment was performed according to accepted guidelines. Surprisingly, 5-year survival was slightly better in the study cohort versus the general population for renal cell carcinoma, lung cancer, colorectal cancer, and thyroid cancer. Long-term immunosuppression with different protocols did not lead to significantly different SIRs, although patients treated with mycophenolate mofetil had the lowest SIR for de novo cancers (1.65, 95% CI = 1.2-2.4). Alcoholic liver disease (SIR = 2.30) and primary sclerosing cholangitis (SIR = 3.40) as indications for LT were associated with an increased risk of de novo malignancies. In conclusion, risk-adapted cancer surveillance is proposed. Tumor treatment performed according to accepted guidelines appears adequate. Mycophenolate may lead to lower long-term risks for de novo cancers. Liver Transpl 19:1252–1261, 2013. © 2013 AASLD.
pH‐ and Redox‐Responsive Poly(ethylene glycol) and Cholesterol‐Conjugated Poly(amido amine)s Based Micelles for Controlled Drug Delivery
Authors: Cheng Weiren , Kumar Jatin N. , Zhang Yong , Liu Ye
Published: October 2013

An optimized condition is identified to prepare linear poly(amido amine)s via Michael Addition polymerization of trifunctional amine, 4‐(aminomethyl)piperidine (AMPD), with an equimolar diacrylamide, N,N‐cystaminebis(acrylamide) (BAC). Poly(ethylene glycol) (PEG) and cholesterol (CE) are conjugated to linear poly(BAC‐AMPD) through the reactions with the secondary amino groups in the backbone, respectively, to form poly(BAC‐AMPD)‐g‐PEG‐g‐CE. The chemical structures of poly(BAC‐AMPD) and poly(BAC‐AMPD)‐g‐PEG‐g‐CE are characterized using NMR and gel permeation chromatography (GPC). Transmission electron microscopy (TEM), dynamic light scattering (DLS) and 1H NMR results show that micelles with PEG shells and hydrophobic cores composed of poly(BAC‐AMPD) and CE are formed via self‐assembly of poly(BAC‐AMPD)‐g‐PEG‐g‐CE in aqueous solution, and the micelles of poly(BAC‐AMPD)‐g‐PEG‐g‐CE can be degraded by the presence of L‐dithiothreitol and show a limited cytotoxicity in vitro. The anti‐cancer drug, doxorubicin (DOX), can be loaded into the micelles. The DOX loaded micelles of poly(BAC‐AMPD)‐g‐PEG‐g‐CE show pH‐ and redox‐responsive drug release and redox‐induced formation of aggregates, and it is shown that the DOX loaded micelles can deliver DOX into cells and show a higher efficacy in killing cancer cells than free drug.
Morphology Control Technologies of Polymeric Materials During Processing
Authors: An Fang‐Zhen , Wang Zhong‐Wu , Hu Juan , Gao Xue‐Qin , Shen Kai‐Zhi , Deng Cong
Published: October 2013

The processing, morphological structure, and properties of polymeric materials are closely related with each other. Morphological structure of polymeric materials is formed in situ under complex temperature and external force fields during processing, and in turn affects the ultimate performances of products. With the increasingly widespread application and more stringent requirement of polymeric materials, improved processing technologies are needed in order to improve product quality. A new processing methodology, i.e., morphology control, appears to achieve a significant improvement by structuring the morphological structure of polymeric materials. This paper presents a summary of four different types of morphology control technologies, namely, shear controlled orientation in injection molding, vibration‐assisted injection molding/extrusion, rotational extrusion, and in situ microfibrillation/formation. Methods of application and their resulting effects on morphological structure and mechanical performances of polymeric materials are presented in a review format.
Block Copolymer Templated Assembly of Active Pd Nanocube Arrays
Authors: Liu Zhicheng , Huang Haiying , He Tianbai
Published: October 2013

Two‐dimensional (2D) palladium nanocube array is achieved on plasma‐etched block copolymer templates, while the well‐aligned nanocubes remain active. Anisotropic nanocubes are site‐selectively assembled on various nanopatterns by capillary force. The nanocube array is proved to be easily tunable, and the dimensional commensurability plays a key role in the configurations of the nanocube assemblies. Not only catalytic nanocube array under confinement but also template for the growth of nanoscale zinc oxide (ZnO) nanorods is exemplified as the potential application of the nanoarray.

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Molecular analysis of the UV‐inducible pili operon from Sulfolobus acidocaldarius
Authors: van Wolferen Marleen , Ajon Małgorzata , Driessen Arnold J. M. , Albers Sonja‐Verena
Published: October 2013

Upon ultraviolet (UV) stress, hyperthermophilic Sulfolobus species show a highly induced transcription of a gene cluster responsible for pili biogenesis: the UV‐inducible pili operon (ups operon). This operon is involved in UV‐induced pili assembly, cellular aggregation, and subsequent DNA exchange between cells. As the system increases the fitness of Sulfolobus cells after UV light exposure, we assume that transfer of DNA takes place in order to repair UV‐induced DNA damages via homologous recombination. Here, we studied all genes present in the ups cluster via gene deletion analysis with a focus on UpsX, a protein that shows no identifiable functional domains. UspX does not seem to be structurally essential for UV‐induced pili formation and cellular aggregation, but appears to be important for efficient DNA transfer. In addition, we could show that pilin subunits UpsA and UpsB probably both function as major pilin subunits in the ups pili.
Foot reconstruction using a serratus anterior muscle flap from the same donor site after failure of a thoracodorsal artery perforator flap
Authors: Kim Sang Wha , Kwon Young Hun , Kim Jeong Tae , Kim Youn Hwan
Published: October 2013

The free flap failure rate for the lower extremities is high, which adversely affects limb salvage efforts. In this article, we report a case of failure of a thoracodorsal artery perforator flap, which was simultaneously reconstructed with a serratus anterior muscle flap from the same donor site. A 56‐year‐old male patient had infected wound for 3 months due to Achilles tendon rupture. We reconstructed the defect using a thoracodorsal artery perforator flap. However, 2 days after the operation, we found the congested flap. We were obliged to discard the whole flap and harvested a serratus anterior muscle flap from the same donor site. The patient's foot healed uneventfully. After flap failure, the use of a second free flap from the same donor site may be an effective and safe procedure in specific cases. © 2013 Wiley Periodicals, Inc. Microsurgery 34:153–156, 2014.
Radiation Induced Long Chain Branching in High‐Density Polyethylene through a Reactive Extrusion Process
Authors: Sardashti Pouyan , Tzoganakis Costas , Polak Maria A. , Penlidis Alexander
Published: October 2013

A reactive extrusion process is developed for the modification of the rheological properties of a high density polyethylene (HDPE) by inducing long chain branching (LCB) using a photoinitiator and ultraviolet (UV) light. A central composite response surface design is selected to design the experimental runs at different photoinitiator concentrations, polymer flow rates, and extruder screw speeds. The selected processing factors at the specified levels produce negligible amounts of gel as indicated by extraction experiments. Linear viscoelastic properties at low frequencies indicate the presence of long chain branches. Both zero shear viscosity and relaxation time of the modified samples are enhanced with the branching. According to further molecular characterization, the molecular weight averages are slightly increased, however, the polydispersity index (PDI) of the modified samples remains the same.
Tissue‐ and column‐specific measurements from multi‐parameter mapping of the human cervical spinal cord at 3 T
Authors: Samson R. S. , Ciccarelli O. , Kachramanoglou C. , Brightman L. , Lutti A. , Thomas D. L. , Weiskopf N. , Wheeler‐Kingshott C. A. M.
Published: October 2013

The aim of this study was to quantify a range of MR parameters [apparent proton density, longitudinal relaxation time T1, magnetisation transfer (MT) ratio, MT saturation (which represents the additional percentage MT saturation of the longitudinal magnetisation caused by a single MT pulse) and apparent transverse relaxation rate R2*] in the white matter columns and grey matter of the healthy cervical spinal cord. The cervical cords of 13 healthy volunteers were scanned at 3 T using a protocol optimised for multi‐parameter mapping. Intra‐subject co‐registration was performed using linear registration, and tissue‐ and column‐specific parameter values were calculated. Cervical cord parameter values measured from levels C1–C5 in 13 subjects are: apparent proton density, 4822 ± 718 a.u.; MT ratio, 40.4 ± 1.53 p.u.; MT saturation, 1.40 ± 0.12 p.u.; T1 = 1848 ± 143 ms; R2* = 22.6 ± 1.53 s–1. Inter‐subject coefficients of variation were low in both the cervical cord and tissue‐ and column‐specific measurements, illustrating the potential of this method for the investigation of changes in these parameters caused by pathology. In summary, an optimised cervical cord multi‐parameter mapping protocol was developed, enabling tissue‐ and column‐specific measurements to be made. This technique has the potential to provide insight into the pathological processes occurring in the cervical cord affected by neurological disorders. © 2013 The Authors. NMR in Biomedicine published by John Wiley & Sons, Ltd.
Synergistic effects of organo‐sepiolite and zinc borate on the fire retardancy of polypropylene
Authors: He M. , Cao W. C. , Wang L. J. , Wilkie C. A.
Published: October 2013

Polypropylene (PP)/sepiolite/zinc borate (BZn) composites were prepared by melt extrusion after pre‐modification of sepiolite with cetyltrimethylammonium bromide. The synergistic effects of organo‐sepiolite (OSEP) and BZn on the fire retardancy of PP were studied. X‐ray diffraction and transmission electron microscopy were used to characterize the morphology of the composite. Thermogravimetric analysis, cone calorimetric analysis, limiting oxygen index, and the UL‐94 protocol (Demaisheng technology Co. Ltd.,Shenzhen,China) were used to assess the thermal stability and fire retardancy of the composites. The fire retardancy of PP was greatly improved by introducing OSEP and BZn. The reduction in peak heat release rate for PP/BZn composites at 10% BZn loading is 62% compared with pristine PP, but increased to 78% for PP/10%BZn/10%OSEP composite. Other fire retardant parameters were also improved. The fire performance index of PP/10%BZn/10%OSEP composite was 0.045 sm2/kW compared with 0.014 sm2/kW of pristine PP. The average mass loss rate was 12.1 g/sec/m2 for the composite with both additives compared with 30.1 g/sec/m2 for pristine PP; the smoke production rate decreased by 37% from 0.117 m2/s of pristine PP to 0.074 m2/s of PP/OSEP/BZn. The char residue of composite increased from 0.6% in pristine PP to 12.19% in the composite. The limiting oxygen index increased from 17.1 in pristine PP to 20.8 in the composite: all the samples could obtain a UL‐94 horizontal burn rating. Copyright © 2013 John Wiley & Sons, Ltd.
Epistatic interactions and drug response
Authors: Weigelt Britta , Reis‐Filho Jorge S
Published: October 2013

The advent of massively parallel sequencing has allowed for an unprecedented genetic characterization of cancers, which has revealed not only the complexity of cancer genomes, but also the fact that tumours from the same anatomical site or even of the same histological and/or molecular subtype display distinct constellations of somatic genetic aberrations. Epistatic interactions (ie the interplay between genetic aberrations) are likely to play pivotal roles not only in terms of tumourigenesis and disease progression, but also in response to therapeutic interventions. In this review, we discuss the challenges posed by the complexity of tumour genomes and epistatic interactions, and approaches for harnessing the wealth of genetic information on human cancers for the implementation of precision medicine. Copyright © 2013 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Factors influencing adherence in long‐term use of statins
Authors: Warren James R. , Falster Michael O. , Fox Danushka , Jorm Louisa
Published: October 2013

Purpose

To assess the factors influencing adherence in long‐term medication use as exemplified by statins.

Methods

Data from an in‐depth survey of Australians aged 45 years and over were linked to national prescription reimbursement data to assess medication possession ratio (MPR) for statins for the middle two years of a four‐year period of statin possession. Poisson regression was used to calculate the relative risk (RR) for adherence (MPR ≥ 80%) for patient characteristics and factors related to access to and need for health care services. Separate models were fit for patients receiving healthcare concession subsidies and those who do not (‘general beneficiaries’).

Results

In the analysis, 42 492 concessional and 16 110 general beneficiary patients were included, with 80.1% and 56.7% showing MPR ≥ 80%, respectively. In both models, RR for adherence was significantly elevated for older (age 65+) and less healthy (worse self‐rated health, pre‐existing heart condition or obese) individuals, and for those who had private health insurance. Significantly lower RR (i.e. more non‐adherence) was found for individuals reporting speaking a language other than English at home, who were smokers, were employed, and had higher levels of education, and for those who reported psychological distress. Income had no significant relationship with adherence, and the pattern of adherence by remoteness of area of residence was inconsistent.

Conclusions

Poor adherence in long‐term use of statins is commonplace, but a number of key predictors—including age, language other than English spoken at home, smoking status and psychological distress—are readily assessable by the prescribing practice. Copyright © 2013 John Wiley & Sons, Ltd.
Effect of core–shell zinc hydroxystannate nanoparticle–organic macromolecule composite flame retardant prepared by masterbatch method on flame‐retardant behavior and mechanical properties of flexible poly(vinyl chloride)
Authors: Li Zhi‐Wei , Shao Bing , Huang Yong‐Shan , Li Xiao‐Hong , Zhang Zhi‐Jun
Published: October 2013

Macromolecule flame retardant melamine‐dicyandiamide‐formaldehyde‐phosphoric acid (denoted as MDFP) was used as the shell material to synthesize zinc hydroxystannate@MDFP (denoted as ZHS@MDFP), a novel composite flame retardant with core–shell structure, via masterbatch method. The morphology and structure of ZHS@MDFP were analyzed by means of transmission electron microscopy, X‐ray powder diffraction, Fourier transform infrared spectrometry, and thermal analysis. Moreover, the effect of ZHS@MDFP as a flame retardant on the flame‐retardant behavior and mechanical properties of flexible poly(vinyl chloride) (denoted as PVC) was investigated. It has been found that as‐synthesized ZHS@MDFP composite flame retardant has core–shell structure. Besides, as‐synthesized ZHS@MDFP as a core–shell flame retardant is superior to ZHS in increasing the limiting oxygen index and decreasing the smoke density rating of PVC, which is because the decomposition of MDFP shell as the blowing agent expands the char layer thereby improving the flame‐retarding capability of ZHS core. More importantly, ZHS@MDFP does not cause damage to the tensile strength and elongation at break of PVC matrix, which implies that the MDFP shell favors to improve the compatibility between ZHS and flexible PVC matrix. POLYM. ENG. SCI., 54:1983–1989, 2014. © 2013 Society of Plastics Engineers
CAPACITY BUILDING: EVIDENCE‐BASED PRACTICE AND ADOLESCENTS ON THE AUTISM SPECTRUM
Authors: Rue Hanna C. , Knox Maria
Published: October 2013

Empirical research in the treatment of autism spectrum disorders (ASDs) has resulted in the identification of numerous evidence‐based interventions (EBIs). Adolescents with an ASD are faced with unique academic challenges, complex social environments, and physiological changes. They often require interventions to aid in acclimating to their evolving social environments and physical changes. One of the many challenges for practitioners working with adolescents is turning research findings into practice. We provide a framework to build capacity within a middle or high‐school setting to implement EBIs for adolescent students with an ASD. Key elements of implementing EBIs in the school setting include: developing a team of professionals dedicated to achieving a system change, a systematic plan, monitoring progress, and a plan for sustainability. Teacher training is an essential part of implementing EBIs in an educational setting. Empirical evidence suggests that teacher training consists of different strategies including in‐vivo training. Accessing resources outside of the school system, such as professionals at universities and teaching hospitals, can aid in training and other aspects of implementing EBIs in the classroom.
Formation of diazohydroxides ArN2OH in aqueous acid solution: polarographic determination of the equilibrium constant KR for the reaction of 4‐substituted arenediazonium ions with H2O
Authors: Sienkiewicz Andrzej , Szymula Marta , Narkiewicz‐Michalek Jolanta , Bravo‐Díaz Carlos
Published: October 2013

In aqueous acid (pH <4) solutions, in the dark, and in the absence of reductants, arenediazonium ions, ArN2+ decompose spontaneously through the rate‐limiting formation of the extremely unstable aryl cation that reacts with any nucleophile present in its solvation shell (DN + AN mechanism). However, in weak acidic and alkaline solutions, ArN2+ react with H2O and OH− at the terminal nitrogen to give azo adducts of the type ArN2OH that are in equilibrium with the parent ArN2+. The diazohydroxide, in this case an acid, is in equilibrium with its conjugate base, and diazoate ArN2O−. The equilibrium constant for reaction with OH− has been determined for a limited number of ArN2+ from kinetic measurements but not with H2O (KR). Here, we have exploited the electrochemical properties of ArN2+ to determine, for the first time, the equilibrium constants KR of formation of 4‐substituted X–ArN2OH (XH, Me, MeO, Br, and NO2), which can decompose in several ways including Z–E isomerization or further reaction with OH− to give diazoate ArN2O−. The technique applied was differential pulse polarography, which is very selective and sensitive. The determined pKR values are 5–6, and they are somewhat higher than those obtained for the reaction of ArN2+ with alcohols ROH (pKDE = 3–5) under similar acidic conditions. The KR values are not very sensitive to changes in the nature of the substituent in the aromatic ring and a linear Hammett plot with a slope of ρ = 0.58 was obtained. Copyright © 2013 John Wiley & Sons, Ltd.
Synthesis and electronic energy‐level regulation of imide‐fused poly(thienylene vinylene) derivatives
Authors: Wang Xiaochen , Gao Chen , Wang Kai , Fan Xi , Wang Haiqiao , Li Xiaoyu , Zhang Zhi‐Guo , Li Yongfang
Published: October 2013

A series of novel poly(thienylene vinylene) derivatives (PTVs), P20‐P24, with imide substituents were designed and synthesized by palladium‐catalyzed Stille coupling polymerization, wherein the imide substituent density was decreased gradually, which allowed us to explicitly study the effect of electron‐deficient substituent on the optical, electrochemical, and photovoltaic properties of the PTVs. All of the four polymers showed broad absorption bands with optical bandgaps between1.66 and 1.78 eV. By reducing density of electron‐deficient imide group, the LUMO energy levels of the polymers could be tuned gradually from −3.75 to −3.43 eV, with HOMO levels upshifted from −5.64 to −5.16 eV. Bulk heterojunction solar cells with the polymers as donor and PC71BM as acceptor demonstrated very different excitons dissociation behavior. With decreasing the imide‐fused unit density, the open‐circuit voltage (VOC) values in the devices decreased from 0.78 to 0.62 V, whereas the short‐circuit currents (JSC) increased from 0 to 2.26 mA cm−2 and then decreased to 1.01 mA cm−2. By adjusting the electron‐withdrawing imide substituent density, power conversion efficiency of the PTVs‐based solar cells can be increased to four times, reached 0.86%. To the best of our knowledge, this is the first systematic study of the relationship between molecular energy level and photovoltaic properties of PTVs. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4975–4982
Synthesis of thermally degradable epoxy adhesives
Authors: Luo Kai , Xie Tao , Rzayev Javid
Published: October 2013

We have developed a new strategy for the synthesis of epoxide‐containing polymers where the pendant reactive groups are connected to the main backbone via thermally labile oxonorbornene groups. The polymers were synthesized by radical 1,4‐polymerization of the appropriate bicyclic diene monomer. The produced polymers can be crosslinked in the presence of a diamine and de‐crosslinked by thermal treatment at 160 °C, which induces retro‐Diels–Alder reaction and cleaves pendant groups from the polymer backbone, as confirmed by differential scanning calorimetry. The potential for the utilization of this polymer as a thermally removable adhesive was demonstrated by a simple adhesion test. This method provides access to thermally cleavable epoxy networks that can be quickly and irreversibly disintegrated into nonvolatile components upon heating to a specified temperature. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4992–4997
Mineralization of Phenol in Water by Catalytic Non‐Thermal Plasma Reactor – An Eco‐Friendly Approach for Wastewater Treatment
Authors: Reddy Pathpireddy Manoj Kumar , Dayamani Allumolu , Mahammadunnisa Shaik , Subrahmanyam Challapalli
Published: October 2013

Degradation of phenol in water was examined in a non‐thermal plasma reactor combined with CeO2, Fe2O3/CeO2, and ZrO2/CeO2 catalysts. Plasma reactor was operated in a dielectric barrier discharge configuration, whereas, catalysts were characterized by XRD, BET, and Raman spectroscopy. The effect of applied voltage, phenol concentration and catalyst addition was studied. Typical results indicated that the degradation efficiency increases with increasing voltage, whereas, the best energy yield was obtained at lower applied voltage. Total organic carbon analyzer confirmed the mineralization of phenol, which was further enhanced by the catalyst addition up to 47.3%. The intermediate compounds formed during the plasma decomposition were identified by gas chromatography mass spectrometry (GC–MS).
Particle‐Arrayed Silver Mesocubes Synthesized via Reducing Silver Oxide Mesocrystals for Surface‐Enhanced Raman Spectroscopy
Authors: Yang Zhongbo , Zhang Lei , You Hongjun , Li Zhiyuan , Fang Jixiang
Published: October 2013

In this study, we demonstrate an easy particle‐mediated protocol using the specific structure of mesocrystal Ag2O sacrificial templates to synthesize highly rough‐cubic Ag mesocages. To the best of our knowledge, the mesocrystal particles are reported for the first time as sacrificial templates for synthesizing metal particles. The obtained Ag mesocages show high surface‐enhanced Raman scattering (SERS) sensitivity because of the highly rough topography formed by arrays of uniform individual Ag nanoparticles. Abundant “hot spots” with greatly enhanced local electromagnetic field are promoted densely on the mesocage surface by the plenty of deep and narrow gaps and the hollow structure. The single‐particle SERS signal generated by the Ag mesocage has an enhancement factor of approximately 109, which is approximately four times higher than the Ag mesocage synthesized using single‐crystal Ag2O particle as a template. Meanwhile, this signal displays a linear dependence on the detected analyte concentration, sensitively down to 1.0 × 10−12
m.
Evaluation of AMG 076, a potent and selective MCHR1 antagonist, in rodent and primate obesity models
Authors: Motani Alykhan S. , Luo Jian , Liang Lingming , Mihalic Jeffrey T. , Chen Xiaoqi , Tang Liang , Li Leping , Jaen Juan , Chen Jin‐Long , Dai Kang
Published: October 2013

Melanin‐concentrating hormone (MCH) regulates food intake through activation of the receptor, MCHR1. We have identified AMG 076 as an orally bioavailable potent and selective small molecule antagonist of MCHR1. In mouse models of obesity, AMG 076 caused a reduction in body weight gain in wild‐type (MCHR1+/+) but not in knockout (MCHR1−/−) mice. The body weight reduction was associated with decreases in food intake and increases in energy expenditure. Importantly, we show that these MCHR1‐dependent effects of AMG 076 were also reflected in improved metabolic phenotypes, increased glucose tolerance and insulin sensitivity. Preliminary data on effects of AMG 076 in obese cynomolgus monkeys are also presented.
Effect of TAT‐obestatin on proliferation, differentiation, apoptosis and lipolysis in 3T3‐L1 preadipocytes
Authors: Ren Guangcai , He Zuyong , Cong Peiqing , Yu Jingwei , Qin Yufeng , Chen Yaosheng , Liu Xiaohong
Published: October 2013

It has been reported that obestatin regulates adipocyte metabolism via receptors on the cell surface. We wondered whether obestatin can interact with intracellular components that activated signalling pathways in adipocytes. Because obestatin (human) only presents one lysine (at position 10), which cannot penetrate the cell membrane, therefore, we used a cell‐permeable peptide TAT (49‐57) as a vector to carry obestatin across the cell membrane. The goal of this study was to further understand the function of obestatin after penetrating the cell membrane. Our results showed that TAT‐obestatin could cross the 3T3‐L1 cell membrane in the absence of cytotoxicity. TAT‐obestatin showed no effect on the proliferation of 3T3‐L1 preadipocytes. In contrast, obestatin significantly stimulated proliferation at a dose of 10‐11 M and 10‐13 M. In addition, TAT‐obestatin demonstrated a more potent inhibitory effect on cell apoptosis induced by serum starvation than that of obestatin. During the progress of adipocyte differentiation, TAT‐obestatin and obestatin had no effect on adipogenesis. In the lipolysis assay, TAT‐obestatin significantly increased glycerol and free fatty acid release from 3T3‐L1 adipocytes after 3 h treatment but showed no significant effect on lipolysis after 24 h and 48 h of treatment. In contrast, obestatin (10‐7 M) had no effect on glycerol release after 3, 24 and 48 h of treatment. The difference between the effect of TAT‐obestatin and obestatin on adipocytes metabolism indicated that TAT‐obestatin may trigger intracellular signalling as well as signalling at the cell membrane. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.
Ethanol induced the formation of β‐sheet and amyloid‐like fibrils by surfactant‐like peptide A6K
Authors: Chen Yongzhu , Tang Chengkang , Xing Zhihua , Zhang Jie , Qiu Feng
Published: October 2013

Self‐assembly of natural or designed peptides into fibrillar structures based on β‐sheet conformation is a ubiquitous and important phenomenon. Recently, organic solvents have been reported to play inductive roles in the process of conformational change and fibrillization of some proteins and peptides. In this study, we report the change of secondary structure and self‐assembling behavior of the surfactant‐like peptide A6K at different ethanol concentrations in water. Circular dichroism indicated that ethanol could induce a gradual conformational change of A6K from unordered secondary structure to β‐sheet depending upon the ethanol concentration. Dynamic light scattering and atomic force microscopy revealed that with an increase of ethanol concentration the nanostructure formed by A6K was transformed from nanosphere/string‐of‐beads to long and smooth fibrils. Furthermore, Congo red staining/binding and thioflavin‐T binding experiments showed that with increased ethanol concentration, the fibrils formed by A6K exhibited stronger amyloid fibril features. These results reveal the ability of ethanol to promote β‐sheet conformation and fibrillization of the surfactant‐like peptide, a fact that may be useful for both designing self‐assembling peptide nanomaterials and clarifying the molecular mechanism behind the formation of amyloid fibrils. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd.
Electrostatic potential of hydrogenated finite‐length carbon nanotubes under an electric field
Authors: Yamanaka Ayaka , Okada Susumu
Published: October 2013

We study the electronic properties of hydrogenated carbon nanotubes under an electric field based on the density functional theory with effective screening medium method. We find that, screening against the external electric field strongly depends on local atomic arrangement due to the inhomogeneous charge distribution arising from the bond alternation induced by the H‐terminated C atoms at the edge region. Besides the screening arising from the bond alternation, unusual electric field screening occurs at the vicinity of the edge C atomic site in zigzag nanotubes.

We also find that the energy gap between the highest occupied and the lowest unoccupied states of armchair and zigzag nanotubes oscillates in triple and double periodicity, respectively, in their units with respect to the length. The electric field induces the charge redistribution in which the charge accumulation and depletion only occur around the H‐terminated C atoms situated near the ends of the nanotubes. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterizations of Al2O3 gate dielectric deposited on n‐GaN by plasma‐assisted atomic layer deposition
Authors: Yoshitsugu Koji , Horita Masahiro , Ishikawa Yasuaki , Uraoka Yukiharu
Published: October 2013

This paper briefly reviews the characterizations of Al2O3 gate dielectric deposited by plasma‐assisted atomic layer deposition (PA‐ALD) on n‐GaN. We report on insulating and physical properties of PA‐ALD Al2O3 film from I‐V characteristics of metal‐insulator‐semiconductor (MIS) diodes and analysis of X‐ray photoelectron spectroscopy (XPS), respectively. Compared to Al2O3 film deposited by thermal ALD method, the PA‐ALD Al2O3 film exhibited higher breakdown field and several orders of magnitude lower leakage current density. Analysis of the current conduction mechanism reveals that the gate leakage current of PA‐ALD Al2O3/n‐GaN MIS diode consisted of Schottky emission (SE) and Fowler‐Nordheim tunneling (FNT). In contrast, it is suggested that trap‐assisted tunneling (TAT) mechanism was dominant in the gate leakage of T‐ALD Al2O3 sample at the middle field range. From the XPS analysis, the band gap of PA‐ALD Al2O3 was estimated about 6.7 eV. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High Throughput Screening of Natural Products for Anti‐mitotic Effects in MDA‐MB‐231 Human Breast Carcinoma Cells
Authors: Mazzio E. , Badisa R. , Mack N. , Deiab S. , Soliman K. F. A.
Published: October 2013

Some of the most effective anti‐mitotic microtubule‐binding agents, such as paclitaxel (Taxus brevifolia) were originally discovered through robust National Cancer Institute botanical screenings. In this study, a high‐through put microarray format was utilized to screen 897 aqueous extracts of commonly used natural products (0.00015–0.5 mg/mL) relative to paclitaxel for anti‐mitotic effects (independent of toxicity) on proliferation of MDA‐MB‐231 cells. The data obtained showed that less than 1.34 % of the extracts tested showed inhibitory growth (IG50) properties <0.0183 mg/mL. The most potent anti‐mitotics (independent of toxicity) were Mandrake root (Podophyllum peltatum), Truja twigs (Thuja occidentalis), Colorado desert mistletoe (Phoradendron flavescens), Tou Gu Cao Speranskia herb (Speranskia tuberculata), Bentonite clay, Bunge root (Pulsatilla chinensis), Brucea fruit (Brucea javanica), Madder root (Rubia tinctorum), Gallnut of Chinese Sumac (Melaphis chinensis), Elecampane root (Inula Helenium), Yuan Zhi root (Polygala tenuifolia), Pagoda Tree fruit (Melia Toosendan), Stone root (Collinsonia Canadensis), and others such as American Witchhazel, Arjun, and Bladderwrack. The strongest tumoricidal herbs identified from amongst the subset evaluated for anti‐mitotic properties were wild yam (Dioscorea villosa), beth root (Trillium Pendulum), and alkanet root (Lithospermum canescens). Additional data was obtained on a lesser‐recognized herb: (S. tuberculata), which showed growth inhibition on BT‐474 (human ductal breast carcinoma) and Ishikawa (human endometrial adenocarcinoma) cells with ability to block replicative DNA synthesis, leading to G2 arrest in MDA‐MB‐231 cells. In conclusion, these findings present relative potency of anti‐mitotic natural plants that are effective against human breast carcinoma MDA‐MB‐231 cell division. Copyright © 2013 John Wiley & Sons, Ltd.
High gain observer for a three‐cell chopper: Design and experimental results
Authors: Ghanes M. , Trabelsi M. , Lin‐Shi X. , Barbot J.‐P. , Retif J.‐M. , Busawon K.
Published: October 2013

As capacitor voltages are necessary for the three‐cell DC–DC chopper control, the estimation of such voltages by an observer is attractive solution in terms of cost. However, due to the hybrid behavior of this structure, the capacitor voltages may be partially or even not observable for a given switching configuration. In other words, the observability matrix associated to the capacitor voltages never has a full rank. In order to make the observer conceivable, this paper proposes a new design by establishing sufficient conditions under which the capacitor voltages can be reconstructed within appropriate specific switching sequence and not necessarily instantly. An interconnected high gain observer is then designed for the considered structure. Furthermore, the analysis of convergence is given according to specific switching sequence, and the bounds of the observer tuning parameters are numerically verified. A significant load current benchmark including a three‐cell chopper is used as prototype to show the performance and the effectiveness of the proposed observer. Copyright © 2013 John Wiley & Sons, Ltd.
Singularity‐avoiding swing‐up control for underactuated three‐link gymnast robot using virtual coupling between control torques
Authors: Lai Xuzhi , Zhang Ancai , Wu Min , She Jinhua
Published: October 2013

An underactuated three‐link gymnast robot (UTGR) is a simple model of a gymnast on a high bar. The control objective of a UTGR is to swing it up from a point near the straight‐down position and to stabilize it at the straight‐up position. To achieve this, we first divide the motion space into two subspaces, swing‐up area and balancing area, and design a controller for each. The design of a swing‐up control law that ensures that the UTGR enters the balancing area is crucial because the UTGR is subject to a nonholonomic constraint and is highly nonlinear during the swing‐up motion. This study focused on how to design a swing‐up control law that contains no singularities. The key concept is the introduction of a virtual coupling between control torques, which converts the problem of avoiding singularities to one of imposing constraints on the parameters of the control law and properly selecting those parameters. A swing‐up control law thus designed ensures that the UTGR enters the balancing area in a natural stretched‐out posture. This makes it easy to stabilize the UTGR in the balancing area. Copyright © 2013 John Wiley & Sons, Ltd.
Nonlinear control under wave actuator dynamics with time‐ and state‐dependent moving boundary
Authors: Cai Xiushan , Krstic Miroslav
Published: October 2013

We consider the stabilization of nonlinear ODE systems with actuator dynamics modeled by a wave PDE whose boundary is moving and is a function of time and of the ODE's state. Such a problem is inspired by applications in oil drilling where the position of the drill bit is a state variable in the ODE modeling the friction‐dominated drill bit dynamics while at the same time being the position of the moving boundary of the wave PDE that models the distributed torsional dynamics of the drillstring. For moving boundaries that depend only on time, we extend the global result recently developed by Bekiaris‐Liberis and Krstic for constant boundaries. For moving boundaries that also depend on the ODE's state, we develop a local result where the initial condition is restricted in such a way that it is ensured that the rate of movement of the boundary (both ‘leftward’ and ‘rightward’) is bounded by unity in closed‐loop. For strict‐feedforward systems under wave actuator dynamics with moving boundaries, the predictor‐based feedback laws are obtained explicitly. The feedback design is illustrated through an example. Copyright © 2013 John Wiley & Sons, Ltd.
Synthesis of satellite footprint patterns from rectangular planar array antenna by using swarm‐based optimization algorithms
Authors: Chatterjee Anirban , Mahanti Gautam Kumar , Ghatak Gourab
Published: October 2013

A pattern synthesis method based on Firefly Algorithm (FA) and Artificial Bee Colony (ABC) optimization has been presented to generate satellite footprint patterns from a rectangular planar array of isotropic antennas by modifying the amplitude, phase, and the state of the array elements. Three cases comprising three different footprints of rectangular, square, and circular boundary are generated from the same array by using two different swarm‐based optimization algorithms FA and ABC. Both the algorithms, following the proposed procedures are able to generate the three different footprint patterns while maintaining a satisfactory lower peak side lobe level and ripple. A comparative analysis has been carried out between FA, ABC, and Genetic Algorithm (GA) for the presented problem in terms of fitness value for the three different cases. The superiority of FA and ABC over GA has been established in terms of finding better solutions for all the three cases of the proposed problem. Copyright © 2013 John Wiley & Sons, Ltd.
Nanoprobes Visualizing Gliomas by Crossing the Blood Brain Tumor Barrier
Authors: Gao Xihui , Li Cong
Published: October 2013

The difficulty in delineating the glioma margins in brain is a major obstacle for its completed resection, which leads to the disproportionately high recurrence and mortality. Besides the fast exertion rate, inadequate sensitivity and non‐targeting specificity, the main reason leading to failure of small molecular probes to define gliomas is their incapability to efficiently cross the blood brain tumor barrier (BBTB). Nanoprobes (NPs) show promise to precisely delineate the geographically irregular tumor margins due to their tunable size/circulation lifetime that maximize their passive intratumoral accumulation and their convenience for surface modification that increases the BBTB transcytosis efficacy, imaging sensitivity and receptor targeting specificity. In this work, the characteristics of the BBTB are addressed from biological and physiological perspectives, strategies are presented to deliver NPs across the BBTB, recent developments of NPs are reviewed for glioma visualization and finally the difficulty and promise for clinical translation of NPs are described. Overall, NPs hold great potential for glioma imaging and treatment by pre‐surgically delineating tumor margins and intra‐operatively guiding tumor excision.