bluuebunny/crossref_metadata_2025 huggingface dataset:
Halophyte Plant Communities Affecting Enzyme Activity and Microbes in Saline Soils of the Yellow River Delta in China
Authors: Cao Di , Shi Fuchen , Koike Takayoshi , Lu Zhaohua , Sun Jingkuan
Published: December 2013

The Yellow River Delta covers a large area of saline soil, which needs to be recovered urgently. As the main local halophytes Suaeda salsa, Phragmites australis, and Tamarix chinensis communities play an important role in the improvement of the soil micro‐environment. Therefore, we investigated the effect of these three salt‐tolerant plant communities on soil enzyme activity in the Yellow River Delta in China. Halophyte plant communities influence the soil micro‐ecosystem in the wetland by exerting effects on the physicochemical properties of the soil, and on enzymes and microbial community. In the soil these enzymes affect the redox potential (catalase) and cycling of carbon (dehydrogenase), nitrogen (protease, urease), and phosphorus (acid phosphatase). We analyzed enzyme activity and the relations between the activity of different enzymes, the physicochemical properties of the soil, and the microbial composition. The activity of five enzymes differed significantly between the plant communities. Soil salinity and microbial community composition all influenced enzyme activity. Catalase, protease and urease activity in the soil of the T. chinensis community was significantly higher than in the other two plant communities. Dehydrogenase and acid phosphatase activity were significantly higher in the soil of the P. australis community than in the other two communities. In the succession of the plant community from herbs to woody plants with different salt tolerance mechanisms, a large aboveground biomass may support the growth of soil enzyme activity and soil microorganism diversity. This study showed that the belowground processes were strongly related with plant community succession in salt marsh ecosystem.
Simulating and modelling the effectiveness of graphical password intersection attacks
Authors: English Rosanne
Published: December 2013

Recognition‐based graphical passwords (RBGPs) are often proposed as an alternative user authentication mechanism. However, discussion of attack resistance often lacks quantitative examination. Establishing the efficacy of countermeasures could allow selection of an appropriate countermeasure for the level of security required by a given system. Furthermore, this information could be used to construct a model to estimate the number of intersection attacks required before success. This research contributes to these goals by establishing effective countermeasures and a model for intersection attacks. The approach involves creating a simulation of intersection attacks using five possible countermeasures and performing analysis to determine efficacy. Results show that using dummy screens does not increase the number of attacks required. It is also shown that increasing the number of challenge screens can increase and reduce the number of attacks required. Also presented is a model for RBGP schemes that can be used to estimate the number of intersection attacks required for a RBGP scheme when configuration values such as the number of challenge screens are known. This allows a quantitative choice of countermeasure for intersection attacks and a calculation that can provide a basis of comparison with other RBGP schemes, which was previously not possible. Copyright © 2013 John Wiley & Sons, Ltd.
Scanning Droplet Cell for Chemoselective Patterning through Local Electroactivation of Protected Quinone Monolayers
Authors: Clausmeyer Jan , Henig Jörg , Schuhmann Wolfgang , Plumeré Nicolas
Published: December 2013

A reagentless strategy for template‐free patterning of uniformly inert surfaces is suggested. A layer of p‐hydroquinone (HQ) protected by the tert‐butyldimethylsilyl (TBDMS) group is electrografted onto glassy carbon electrodes. Chemoselective activation is performed through electrochemically controlled cleavage of the TBDMS group, which yields the redox‐active surface‐confined quinone moieties. The latter are shown to undergo electrochemically induced Michael addition, which serves for subsequent functionalization of the electrode surface. Patterning of the TBDMS–quinone‐modified surface is accomplished by using selective localized cleavage of the protecting group. State‐of‐the‐art direct‐mode scanning electrochemical microscopy (SECM) patterning fails to yield the anticipated interfacial reaction; however, the electrochemical scanning droplet cell (SDC) is capable of conducting the localized chemoselective reaction. In a small area, dictated by the dimensions of the droplet, electrochemically induced cleavage of the protecting group can be performed locally to give rise to arrays of active quinone spots. Upon deprotection, the redox signals, attributed to the hydroquinone/benzoquinone couple, provide the first direct evidence for chemoselective electrochemical patterning of sensitive functionalities. Subsequent SECM studies of the resulting modified areas demonstrate spatial control of the proposed patterning technique.
Multicomponent Cascade Assembly for Quinolinopyranpyrazole Architectures
Authors: Bakthadoss Manickam , Devaraj Anthonisamy , Kannan Damodharan
Published: December 2013

A highly efficient, multicomponent protocol for the construction of functionalized quinolinopyranpyrazole scaffolds with high stereoselectivity has been developed through the application of a domino reaction. All the quinolinopyranpyrazoles were synthesized under solvent‐ and catalyst‐free conditions and required no work‐up or column chromatography.
High‐Pressure‐Mediated Extension of the Privileged Steroid Scaffold
Authors: Blanco‐Ania Daniel , Aben René W. M. , van Berkom Leon W. A. , Scheeren Hans W. , Rutjes Floris P. J. T.
Published: December 2013

The commercially available steroid dehydroepiandrosterone 3‐acetate (DHEA) was converted into new, highly functionalized spiro derivatives by modification of the D‐ring. The transformation proceeded through conversion of the C‐17 carbonyl group into an electron‐deficient alkene, followed by either [2+2] or [4+2] cycloaddition. The cycloaddition reactions were successful for alkylidene malononitriles and 2‐cyano acrylates. Application of high pressure (15 kbar) was essential for good conversions due to the high steric hindrance on position C‐17. The cycloadducts formed from the reaction of 2‐cyano acrylates and Danishefsky's diene have high potential for further functionalization.
A Gricean approach to the use of consensus and distinctiveness in causal attributions of verbally described interpersonal events
Authors: Maris Stefanie , Hoorens Vera
Published: December 2013

Various causal attribution theories, starting with the covariation model, argue that people use consensus, distinctiveness, and consistency information to causally explain events and behaviors. Yet, the visual presentation of the covariation model in the form of a cube is based on the assumptions that these dimensions generally affect attributions independently, symmetrically, and equally. A Gricean analysis suggests that these assumptions may not generally hold in the case of causal judgments for verbally communicated interpersonal events. We had participants judge the causal role of an actor and a patient in interpersonal events that were described through actor‐verb‐patient sentences under high versus low consensus and distinctiveness (Studies 1, 2, and 3) or without such information (Studies 2 and 3). As predicted by Gricean logic, consensus and distinctiveness effects on causality ratings depended on the target whose causal role participants assessed, on the information about the alternative dimension, and, most consistently, on consensus and distinctiveness being high versus low. Copyright © 2013 John Wiley & Sons, Ltd.
The impact of smoke on walking speed
Authors: Fridolf Karl , Andrée Kristin , Nilsson Daniel , Frantzich Håkan
Published: December 2013

In fire safety engineering, information about the expected walking speed of occupants through smoke is often one factor that is of interest to the designer. However, despite the fact that research already in the 1970s demonstrated that people tend to evacuate through smoke, little research has been performed on the topic since, and evidently, there is a lack of data on walking speed in smoke. This has created a situation where fire safety engineering assessments of the required safe escape time may be intimately associated with high uncertainties, especially for buildings in which people can be expected to evacuate long distances through smoke, for example, underground transportation systems. In order to address the lack of data on movement through smoke, 133 data points on individual walking speed in smoke are presented in this paper. The data lie within an extinction coefficient range of 1.2–7.5 m−1. In line with previous studies, it is demonstrated that the level of smoke density has a negative impact on the walking speed, whereas no significant effects of inclination, type of floor material, gender, age and height could be found in the data. In this paper, recommendations are also provided on how designers should treat the data in their fire safety risk assessments, depending on the type of risk analysis method, that is, if the designer is performing a deterministic analysis or a quantitative risk analysis. It is argued that this information can be used to reduce the uncertainty in future risk analyses involving egress calculations. Copyright © 2013 John Wiley & Sons, Ltd.
Distinct patterns of global promoter methylation in early stage chronic lymphocytic leukemia
Authors: Ronchetti Domenica , Tuana Giacomo , Rinaldi Andrea , Agnelli Luca , Cutrona Giovanna , Mosca Laura , Fabris Sonia , Matis Serena , Colombo Monica , Gentile Massimo , Recchia Anna Grazia , Kwee Ivo , Bertoni Francesco , Morabito Fortunato , Ferrarini Manlio , Neri Antonino
Published: December 2013

Genomic and epigenomic studies of chronic lymphocytic leukemia (CLL) are reshaping our understanding of the disease and have provided new perspectives for a more individualized diagnosis and new potential therapeutic targets. In this study, the global promoter methylation profile was determined in highly purified B‐cells from 37 (Binet stage A) CLL patients, using high‐resolution methylation microarrays (27,578 CpG). Overall, the methylation pattern correlated with the major biological (ZAP‐70 and CD38), and molecular (IGHV mutation) markers, distinguishing CLL cases according to IGHV mutational status. Cell adhesion molecules were enriched in the signature of unmutated (UM) versus mutated (M‐) CLL. Moreover, in M‐CLL CpG hyper‐methylation in three genes, including SPG20, was significantly anti‐correlated with the corresponding gene expression level. Finally, the correlation between the methylation pattern and clinical parameters was investigated. Notably, out of 42 methyl‐probes that were significantly associated with progression free survival (PFS), hyper‐methylation of SPG20 was also positively associated with PFS. These data support the notion that epigenetic changes have clinical impact in CLL and may contribute to the identification of novel candidate disease‐associated genes potentially useful to predict the clinical outcome of early stage CLL patients. © 2013 Wiley Periodicals, Inc.
Prognostic value of the proliferation marker Ki‐67 in laryngeal carcinoma: Results of the Accelerated Radiotherapy with Carbogen Breathing and Nicotinamide phase III randomized trial
Authors: Rademakers Saskia E. , Hoogsteen Ilse J. , Rijken Paul F. , Terhaard Chris H. , Doornaert Patricia A. , Langendijk Johannes A. , van den Ende Piet , van der Kogel Albert J. , Bussink Johan , Kaanders Johannes H.
Published: December 2013

Background

The prognostic and predictive value of the proliferation marker Ki‐67 was investigated in a randomized trial comparing accelerated radiotherapy with carbogen breathing and nicotinamide (ARCON) to accelerated radiotherapy in laryngeal carcinoma.

Methods

Labeling index of Ki‐67 (Li Ki‐67) in immunohistochemically stained biopsies and the colocalization with carbonic anhydrase IX (CAIX) were related to tumor control and patient survival.

Results

On average, node‐positive patients had a higher Li Ki‐67 (median 14% vs 8%; p < .01). In patients with a high Li Ki‐67, the 5‐year regional control and metastases‐free survival were 79% versus 96% (p < .01) and 71% versus 88% (p = .05) for accelerated radiotherapy and ARCON, respectively. The 5‐year local control and disease‐specific survival were not significantly different. Patients with low Ki‐67 expression had an excellent outcome with accelerated radiotherapy alone.

Conclusion

Patients with laryngeal carcinomas with high proliferative activity are at increased risk of regional and distant metastases formation. This risk can be reduced by treatment with ARCON. © 2014 Wiley Periodicals, Inc. Head Neck 37: 171‐176, 2015
Phase II trial of sorafenib in advanced salivary adenoid cystic carcinoma of the head and neck
Authors: Thomson David J. , Silva Priyamal , Denton Kim , Bonington Suzanne , Mak Soo K. , Swindell Ric , Homer Jarrod , Sykes Andrew J. , Lee Lip W. , Yap Beng K. , Slevin Nicholas J.
Published: December 2013

Background

There is a need to improve the systemic treatment of advanced adenoid cystic carcinoma (ACC). Response rates to chemotherapy are poor and preliminary investigations of molecularly targeted agents have been disappointing. In this study, we evaluate sorafenib, an oral multikinase inhibitor, which has an attractive targeting profile for this disease.

Methods

In a single‐arm phase II trial, patients with unresectable locally recurrent and/or metastatic ACC were treated with sorafenib 400 mg bid.

Results

Twenty‐three patients, median age 51 years, were recruited from 2009 to 2011. Median progression‐free survival (PFS) and overall survival (OS) were 11.3 and 19.6 months, respectively. PFS at 6 and 12 months were 69.3% and 46.2%, respectively. Sorafenib was only reasonably well tolerated, and 13 patients (57%) experienced grade 3 toxicity.

Conclusion

Sorafenib showed modest activity in ACC with a 12‐month PFS of 46.2%. Sorafenib 400 mg bid was associated with significant toxicity and, taken together with limited effectiveness, cannot be enthusiastically recommended for further evaluation. © 2014 Wiley Periodicals, Inc. Head Neck 37: 182‐187, 2015
Lymphadenopathy: Defining a palpable lymph node
Authors: Xu Jason J. , Campbell Gordon , Alsaffar Hussain , Brandt Michael G. , Doyle Philip C. , Glicksman Jordan T. , Fung Kevin
Published: December 2013

Background

The threshold size required to detect lymphadenopathy via palpation has never been formally determined. The purpose of this study was to determine the threshold, sensitivity, and error of node palpation and how this changes with experience.

Methods

Lymphadenopathy models were created using polyvinyl alcohol cryogel (PVA‐C) to mimic tissue tactility. Node diameter ranged from 0.5 to 4 cm. Study subjects were medical students, otolaryngology residents, and otolaryngology consultants. Each subject provided 22 estimates of size. Primary outcomes were the sensitivity, error (true vs estimated size), and threshold of palpation.

Results

Thirty subjects completed the study. Sensitivity was 60%, 74%, and 86% for students, residents, and consultants, respectively (p < .01). Error was 0.88 cm, 0.61 cm, and 0.57 cm, respectively (p < .05). Palpation threshold was 1.32 cm, 0.83 cm, and 0.75 cm, respectively (p < .05). All participants detected nodes ≥2 cm, whereas consultants detected nodes ≥1 cm.

Conclusion

Experience is associated with decreased palpation threshold and error, and increased sensitivity. Educational interventions should target nodes <2 cm. © 2014 Wiley Periodicals, Inc. Head Neck 37: 177‐181, 2015
Association of Serum Uric Acid and Incident Nonspine Fractures in Elderly Men: The Osteoporotic Fractures in Men (MrOS) Study
Authors: Lane Nancy E , Parimi Neeta , Lui Li-Yung , Wise Barton L , Yao Wei , Lay Yu-An Evan , Cawthon Peggy M , Orwoll Eric ,   for the Osteoporotic Fractures in Men (MrOS) Study Group
Published: December 2013

Uric acid (UA) is produced from purines by the enzyme xanthine oxidase, and elevated levels may cause arthritis and kidney stones. Conversely, UA also appears to function as an antioxidant and may protect against the oxidative stress associated with aging and disease. We performed a prospective fracture case-cohort study to understand the relation of UA and fracture risk in older men enrolled in the Osteoporotic Fractures in Men (MrOS) study. In the cohort of 5994 men aged 65 years and older attending the baseline MrOS examination, we evaluated a subgroup 1680 men in a case-cohort study design. The analytic group included 387 men with incident nonspine fractures (73 hip) and a random sample of 1383. Serum UA was measured in baseline serum samples. Modified proportional hazards models that account for case-cohort study design were used to estimate the relative hazards (RH) of hip and nonspine fracture in men for serum UA. Models were adjusted for age, race, clinic site, body mass index, vitamin D, parathyroid hormone, walking speed, Physical Activity Scale for the Elderly (PASE) score, frailty, and total. Subjects with incident nonspine fractures were older, had lower total hip bone mineral density (BMD), and higher serum phosphorus. There was an 18% decreased risk of nonspine fractures (95% confidence interval [CI] 0.71–0.93; p = 0.003) per 1 SD increase of baseline serum and 34% decreased risk of nonspine fractures in quartile 4 of UA versus quartiles 1, 2, and 3 (95% CI 0.49–0.89; p = 0.028) compared with nonfracture cases after multivariate adjustment. Hip fractures were not significantly associated with UA. Total hip BMD was significantly higher in the group of men with high UA levels compared with lower UA levels and increased linearly across quartiles of UA after multivariate adjustment (p for trend = 0.002). In summary, higher serum UA levels were associated with a reduction in risk of incident nonspine fractures but not hip fractures and higher hip BMD. © 2014 American Society for Bone and Mineral Research.
EMBEDDING THE VULNERABLE INTO THE MILLENNIUM DEVELOPMENT GOALS: SOCIAL PROTECTION IN POVERTY REDUCTION STRATEGY PAPERS
Authors: Elkins Meg
Published: December 2013

Social protection and equity are missing elements of the Millennium Development Goals. Both are essential to redress the situation of the most vulnerable. This study provides a comprehensive review of social protection packages in Poverty Reduction Strategy Papers and devises an index to evaluate the extent of a country's level of social protection in its development strategy. The findings show that the social protection agenda in Poverty Reduction Strategy Papers is more pronounced in countries with higher levels of income and lower levels of ethnic diversity and that social assistance packages are more aligned to higher levels of official development assistance and governance. Copyright © 2013 John Wiley & Sons, Ltd.
BOLD MRI in the brain of fetal sheep at 3T during experimental hypoxia
Authors: Schoennagel Bjoern P. , Yamamura Jin , Fischer Roland , Tavares de Sousa Manuela , Weyhmiller Marcela , Birkelbach Moritz , Kooijman Hendrik , Adam Gerhard , Wedegaertner Ulrike
Published: December 2013

Purpose

To calculate regional fetal brain oxygen saturation (sO2) during hypoxia in sheep.

Materials and Methods

Eight pregnant ewes were examined at a 3T MR‐scanner using blood oxygenation level‐dependent magnetic resonance imaging (BOLD‐MRI) to measure signal intensity changes of the fetal brain during a control period and a period of induced hypoxia. Regions of interest were placed in the fetal cerebrum to assess ΔR2* from GRE signal intensity plateaus (Scontrol, Shypoxia) and the relation between ΔR2* and ΔpO2 was analyzed. A probe was placed surgically in the fetal brain to directly measure local pO2 as a reference standard. Baseline and hypoxic pO2 values were recorded and compared (ΔpO2).

Results

Mean fetal brain pO2 decreased from 14.3 mmHg (95% confidence interval [CI]: 10–19) to 3.4 mmHg (95% CI: 2–5) during hypoxia (mean ΔpO2 = 10.9 mmHg and ΔR2* = −5s−1). A significant correlation between ΔR2* and ΔpO2 was noted (r = 0.93, P < 0.001), and conversion of pO2 into sO2 resulted in a linear regression coefficient of (−0.14 ± 0.01)s−1/% (r2 = 0.91).

Conclusion

Measured fetal brain BOLD‐MRI was compared and converted to pO2, followed by calculation of cerebral sO2. J. Magn. Reson. Imaging 2015;41:110–116. © 2013 Wiley Periodicals, Inc.
Fast Fourier transforms for the evaluation of convolution products: CPU versus GPU implementation
Authors: Van de Wiele B. , Vansteenkiste A. , Van Waeyenberge B. , Dupré L. , De Zutter D.
Published: December 2013

In a large variety of research areas, convolution products that relate a physical quantity in some observation points with their sources are encountered. When the sources and the observation points coincide, the numerical evaluation of the physical quantity typically leads to order N2 numerical problems. Here, fast Fourier transforms are widely used to reduce the computations to order Nlog N complexity. When adopting Fourier transforms (FFT) for finite physical problems, zero padding is required. Hence, in 2D and 3D problems, an optimization of the evaluation of the convolution product includes a non‐execution of Fourier transforms on arrays containing only zeros in the forward 2D or 3D FFT scheme and their corresponding arrays in the inverse 2D or 3D FFT scheme. This paper describes the implementation of such an approach on graphical processing units (GPUs) and compares the time gains on GPU and on CPU. It is found that on CPU, the speedup corresponds with the theoretical limit, while in the GPU implementation, the memory bandwidth limits the speedup ratio. Copyright © 2013 John Wiley & Sons, Ltd.
Enhancement of Achilles tendon repair mediated by matrix metalloproteinase inhibition via systemic administration of doxycycline
Authors: Kessler Michael W. , Barr Jerome , Greenwald Robert , Lane Lewis B. , Dines Joshua S. , Dines David M. , Drakos Mark C. , Grande Daniel A. , Chahine Nadeen O.
Published: December 2013

Collagenases or matrix metalloproteinases (MMPs) have been shown to play an important role in the matrix degradation cascade associated with Achilles tendon rupture and disease. The goal of this study was to examine the effects of daily administration of doxycycline (Doxy) through oral gavage on MMP activity and on the repair quality of Achilles tendons in vivo. Our findings indicate that Achilles tendon transection resulted in increasing MMP‐8 activity from 2 to 6 weeks post‐injury, with peak increases in activity occurring at 4 weeks post‐injury. Doxy adiministration at clinically relevant serum concentrations was found to significantly inhibit MMP activity after continuous treatment for 4 weeks, but not for continuous administration for shorter durations (96 h or 2 weeks). Extended doxy administration was also associated with improved collagen fibril organization, and enhanced biomechanical properties (stiffness, ultimate tensile strength, maximum load to failure, and elastic toughness). Our findings indicate that a temporal delay exists between Achilles tendon transection and associated increases in MMP‐8 activity in situ. Our findings suggest that inhibition of MMP‐8 at its peak activity levels ameliorates fibrosis development and improves biomechanical properties of the Achilles tendon. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:500–506, 2014.
Structural dynamics of 4‐cyanobenzaldehyde in S2(ππ*) state
Authors: Yang Yi , Pan Sheng , Xue Jia‐Dan , Zheng Xuming , Fang Wei‐Hai , Phillips David Lee
Published: December 2013

The excited state structural dynamics of 4‐cyanobenzaldehyde (p‐CNB) were studied by using the resonance Raman spectroscopy and the quantum mechanical calculations. The experimental A‐ and B‐band absorptions were, respectively, assigned to the major nO → π3* and π2 → π3* transitions according to the B3LYP‐TD/6‐31G(d) and CIS/6‐31G(d) computations, and the resonance Raman spectra. It was determined that the actual S2(π2π3) state was in energy lower than S3(π1π3), which was just opposite to the B3LYP‐TD/6‐31G(d) calculated order of the S2(π1π3) and S3(π2π3). The vibrational assignments were carried out for the A‐ and B‐band resonance Raman spectra. The B‐band resonance Raman intensities of p‐CNB were dominated by the C2–C3/C5–C6 symmetric stretch mode ν8, the overtones nν8 and their combination bands with the ring C–H bend mode ν17, the C9–N10 stretch mode ν6, the C7–O8 stretch mode ν7 and the remaining modes. The conical intersection between S1(nOπ3) and S2(π2π3) states of p‐CNB was determined at complete active space self‐consistent field (CASSCF)(8,7)/6‐311G(d,p) level of theory. The B‐band short‐time structural dynamics and the corresponding decay dynamics of p‐CNB were obtained by analysis of the resonance Raman intensity pattern and CASSCF computations. The resonance Raman spectra indicated that CI[S1(nOπ3)/S2(π1π2π3π4)] located nearby the Franck–Condon region. The excited state decay dynamics evolving from the S2, FC(π2π3) to the S1(nOπ3) state was proposed. Copyright © 2013 John Wiley & Sons, Ltd.
Thermosensitive molecularly imprinted hydrogel cross‐linked with N‐malely chitosan for the recognition and separation of BSA
Authors: Zhang Cenjin , Jia Xiaoping , Wang Yuzhi , Zhang Min , Yang Shan , Guo Junxia
Published: December 2013

A novel temperature‐sensitive molecularly imprinted hydrogel composed of N‐isopropylacrylamide and acrylamide has been prepared by using free‐radical polymerization and was cross‐linked by modified water‐soluble N‐maley chitosan in aqueous solution. BSA (pI 4.9, MW 66.0 kDa) was used as the template protein. The produced hydrogels were characterized by environmental SEM to reveal the microcosmic morphology. A microporous structure was only found in the imprinted hydrogel, while no obvious microporous structure was found in nonimprinted hydrogels. The lower critical solution temperature of the hydrogels was 34°C, and the optimal binding conditions were tested, namely, the adsorption equilibrium time of 6 h and initial BSA concentration of 1.0 mg/mL. The adsorption capacity Qmax was determined by Langmuir isotherm plots and was 5.72 mg/g for imprinted hydrogel and 1.18 mg/g for nonimprinted hydrogels. A separation factor (β) of 4 was obtained when bovine hemoglobin (pI 6.9, MW 64.0 kDa) was selected as the particular reference protein. Molecular weights and pIs were chosen to investigate the selectivity of the hydrogels. It was shown that the shape memory and the size effect were the major factors for the recognition. This imprinted hydrogel was used to specifically adsorb the BSA from the protein mixture.
Screening of xanthine oxidase inhibitors in complex mixtures using online HPLC coupled with postcolumn fluorescence‐based biochemical detection
Authors: Li Deqiang , Li Shaoping , Zhao Jing
Published: December 2013

Xanthine oxidase (XO) catalyzes the metabolism of hypoxanthine and xanthine to uric acid, the overproduction and/or underexcretion of which could cause the incidence of hyperuricemia such as gout. Herein, the inhibition of XO is recognized as one of the therapeutic approaches to treat gout. In the present study, an off‐line fluorescence‐based microplate method was first developed for an XO assay in which the enzyme converted pterin to its fluorescent metabolite isoxanthopterin. Then, a postcolumn continuous XO assay as a means of bioactivity assessment was coupled to HPLC separation to establish the online HPLC with diode array detection, biochemical detection, and MS/MS system for the screening of XO inhibitors. The availability of the online system was first tested with a positive drug, allopurinol, a well‐known XO inhibitor, and subsequent analysis of Scutellaria baicalensis extract showed that two main bioactive compounds with XO inhibitory activities were observed, indicating that the developed online system was applicable to complex mixtures.
PE/Chlorinated‐PE Blends and PE/Chlorinated‐PE/Graphene Oxide Nanocomposites: Morphology, Phase Miscibility, and Interfacial Interactions
Authors: Mittal Vikas , Luckachan Gisha Elizabeth , Matsko Nadejda B.
Published: December 2013

The microstructure of high‐density polyethylene (PE) and chlorinated polyethylene (CPE) blends, as well as their composites with graphene oxide (GO) is characterized. The filler dispersion improves as the extent of chlorination is enhanced. The platelets are also observed to be covered with a harder phase by atomic force microscopy (AFM), due to the stronger nucleating action of the graphene clusters, along with the alignment or ordering of the CPE phase at the interface with the filler. The filler and the CPE phases are observed to undergo chemical interaction during solution mixing, which enhances during melt mixing of the CPE–GO masterbatch with the PE matrix. The majority of the Cl atoms in the CPE chains are observed to be depleted during chemical reaction or thermal degradation at the melt compounding temperature, resulting in chlorine‐free materials.

image
Development of Tissue Adhesives Based on Amphiphilic Isocyanate‐Terminated Trimethylene Carbonate Block Copolymers
Authors: Bochyńska Agnieszka I. , Sharifi Shahriar , van Tienen Tony G. , Buma Pieter , Grijpma Dirk W.
Published: December 2013

In this study, novel 3‐armed star‐shaped isocyanate‐terminated block copolymers based on trimethylolpropane ethoxylate (TMPE) and trimethylene carbonate (TMC) varying in composition were designed and synthesized. By reaction with water, networks were formed. The characteristics of these networks were compared with those prepared from analogous linear structures based on polyethylene glycol (PEG) and TMC.

Tensile testing of the networks highlighted good mechanical properties. In lap shear adhesion tests to chamois leather, very good bonding strengths of up to 0.6 MPa were obtained. These values compare favorably with those of Dermabond®, which is currently one of the strongest clinically used tissue adhesives.
Effect of Pore Characteristics on Mechanical Properties and Annulus Fibrosus Cell Seeding and Proliferation in Designed PTMC Tissue Engineering Scaffolds
Authors: Blanquer Sébastien B.G. , Haimi Suvi P. , Poot André A. , Grijpma Dirk W.
Published: December 2013

Degeneration of the intervertebral disk is the main cause of chronic back pain. Disk degeneration often leads to tearing of the annulus fibrosus (AF) and extrusion of the nucleus pulposus. As the current surgical strategies are suboptimal, reconstruction of the AF tissue by a tissue engineering strategy has emerged as an alternative. However, regeneration of the AF is challenging due to its complex and non‐homogeneous structure. Since there is a lack of knowledge regarding the effects of scaffold pore sizes on the behavior of human AF cells (hAFCs), scaffolds with a well‐defined and controlled pore architecture with pore sizes ranging from 230–420 µm were prepared by stereolithography. The scaffolds were prepared from the crosslinked biodegradable elastomer poly(trimethylene carbonate) (PTMC). The compression modulus of the scaffolds was inversely related to the pore size and ranged from 0.31–0.21 MPa. These values are similar to those reported for native AF tissue. Seeded hAFCs adhered to the PTMC network and proliferated well in all scaffolds during a culture period of 14 days. However, cell distribution was less homogeneous in the scaffold with 230 µm pore size. In view of its relatively high stifness, the latter scaffold is most suitable for AF tissue engineering, provided that the cell seeding procedure in this scaffold is optimized.
Human Adipose Stem Cells in Chondrogenic Differentiation Medium without Growth Factors Differentiate Towards Annulus Fibrosus Phenotype In Vitro
Authors: Gebraad A. W. H. , Miettinen S. , Grijpma D. W. , Haimi S. P.
Published: December 2013

Intervertebral disc degeneration is the main cause of chronic back pain. Disc degeneration mainly leads to tearing of annulus fibrosus (AF), which is with current methods difficult to restore and impossible to regenerate. Stem cell technology offers a potential technique to repair the ruptured AF by enabling new matrix synthesis at the defect site.

Previous studies have shown that human adipose stem cells (hASCs) are able to differentiate towards AF phenotype when treated with suitable growth factors. There are concerns about the use of growth factors in clinical applications because of their short half‐lives, high costs and low effectiveness. The main aim of this research project was to regenerate AF tissue in vitro using hASCs and serum free chondrogenic medium without supplementation of growth factors.

Differentiation of hASCs was induced by using the micromass culture technique. Human annulus fibrosus cell (hAFCs) cultured in commercial AF growth medium were used as positive control. Assessment of AF phenotype of hASCs and hAFCs was done at 14 and 21 days of culture.

Quantification of sulphated glycosaminoglycan (GAG) content showed that hASCs cultured in chondrogenic medium expressed similar levels of sulphated GAGs as hAFCs. qRT‐PCR confirmed the similarity of the differentiated hASCs with AF phenotype. Several markers for AF phenotype (aggrecan, collagen type I and glypican‐3) were expressed in both hAFCs and differentiated hASCs.

This is the first study that demonstrated that hASCs can be differentiated towards AF phenotype using serum free chondrogenic medium without growth factors. In a next step, scaffolds manufactured from biodegradable polymers will be used in combination with ASCs to find an optimal construct to repair AF defects.
Effect of Surface Morphology of Poly(ϵ‐caprolactone) Scaffolds on Adipose Stem Cell Adhesion and Proliferation
Authors: Diban Nazely , Haimi Suvi P. , Bolhuis‐Versteeg Lydia , Teixeira Sandra , Miettinen Susanna , Poot André A. , Grijpma Dirk W. , Stamatialis Dimitrios
Published: December 2013

The effect of the surface morphology of flat poly(ϵ‐caprolactone) (PCL) scaffolds on human adipose stem cell (hASC) adherence and proliferation was studied. During fabrication of the scaffolds by phase inversion, the employment of different non‐solvents (water (W), ethanol (EtOH) or isopropanol (IPA)) led to distinct surface morphologies. It was found that PCL scaffolds fabricated using IPA as a non‐solvent had a higher roughness and porosity compared to the other groups. Moreover, during culturing of hASCs under static conditions, best cell attachment, spreading and growth were observed on the PCL scaffold. Our results show the potential of PCL scaffolds prepared using IPA as a non‐solvent for especially soft tissue engineering applications.
Ring Opening Polymerization of Organic Carbonates Using CO2 ‐ Carbene Adducts as Effective Organo Catalyst
Authors: Reitz A. , Wilhelm R. , Kuckling D.
Published: December 2013

In this study we successfully synthesized Poly(trimethylene carbonate) (PTMC) through carbene‐catalysed ring opening polymerization. The use of CO2‐adducts decreases the air and moisture sensitivity of the carbene and improves the controllability of the reaction. The carbene is freed through dissolving and heating. The reaction can be done in bulk or in solution. Improvements to the system can be made by varying temperature and solvent. We could show that bulk polymerization allows the synthesis of PTMC in a short span of time and good yields.
Rheological and Turbidity Study of Fibrin Hydrogels
Authors: Wedgwood Jennifer , Freemont Anthony J. , Tirelli Nicola
Published: December 2013

Fibrin hydrogels prepared from different fibrinogen concentrations (12.5, 25 and 50 mg/mL) were studied through oscillatory rheology (gelation kinetics, stress amplitude tests and frequency sweeps), static experiments (creep and recovery tests) and turbidity (gelation kinetics). The experimental parameters obtained from these measurements (including gel point, characteristic times for different kinetic phases, loss and storage moduli), were used to gain some insight on the processes concurring to form the network structure of fibrin hydrogels. Here, we show (turbidity measures) that lateral fibre aggregation appears to be significantly depressed with increasing fibrinogen concentration. Among other important findings, a caveat in using absolute data of mechanical properties from gelation kinetics: we have shown that at low fibrinogen concentration, the actual modulus values are significantly affected by the application of shear stress during gelation.
Synthesizing higher nitride of molybdenum (Mo) and iron (Fe) in ammonia (NH3) gas stream under irradiation of concentrated solar beam in a solar furnace
Authors: Shohoji N. , Almeida Costa Oliveira F. , Cruz Fernandes J. , Guerra Rosa L. , Rodríguez Garcia J. , Canadas Martínez I. , Ramos Miñarro C. , Magalhães T. , Cestari F.
Published: December 2013

Flowing gaseous ammonia NH3 with suppressed extent of dissociation (un‐cracked NH3) is acknowledged to function as a powerful nitriding medium to realize formation of metal nitride MNx with considerably high N/M ratio x that cannot be achieved through reaction of M with N2 gas. For example, mono‐nitride δ‐MoN of Mo and ε‐FeNx phase of Fe with x = 0.33 ˜ 0.50 (i. e. hypo‐stoichiometric sub‐nitride ε‐Fe2N) were reported to be difficult to prepare in N2 gas environment even at elevated pressure but might be synthesized in flowing NH3 gas at normal pressure when reaction temperature and NH3 gas flow rate were set adequately. In the present work, nitriding experiments for Mo and Fe were carried out in flowing NH3 gas under irradiation with concentrated solar beam. The acquired experimental evidences demonstrated that temperature range for formation of δ‐MoN was somewhat extended in flowing NH3 gas under heating with concentrated solar beam compared with that under heating in conventional laboratory or industrial electric furnace. On the other hand, no such merit of extending temperature range for formation of ε‐Fe2N in flowing NH3 gas was detected in the present work under heating with concentrated solar beam.
Individualism/collectivism, charitable giving, and cause‐related marketing: a comparison of Chinese and Americans
Authors: Wang Ye
Published: December 2013

With the global expansion of cause‐related marketing (CRM), advertisers need to know whether and how cultural and societal differences impact attitude toward CRM across markets. To add to that knowledge, the present study identifies two consumer traits, that is, individualism/collectivism and perception of individual charitable giving as a social norm, and investigates and compares their influence on attitude toward CRM. By conducting surveys with Chinese and American samples, the present study found that gender, horizontal collectivism (HC), and perception of individual charitable giving as a social norm were significantly associated with attitude toward CRM in the American sample, whereas horizontal individualism, HC, and vertical collectivism were significant predictors of attitude toward CRM in the Chinese sample. Theoretically, these findings suggest that associations between one cultural dimension and the attitude toward CRM are independent to relationships involving other dimensions. And the particular circumstance of a local market may determine which consumer traits will actually have a significant association with attitude toward CRM. Practically, the findings suggest that advertisers may want to choose social causes that have national impact in China because there is a tendency of achieving egoistic enhancement through individual charitable giving whereas social causes that are relevant to female consumers are better strategic choices in the USA.

Copyright © 2013 John Wiley & Sons, Ltd.
An Overview of Plant Volatile Metabolomics, Sample Treatment and Reporting Considerations with Emphasis on Mechanical Damage and Biological Control of Weeds
Authors: Beck John J. , Smith Lincoln , Baig Nausheena
Published: December 2013

Introduction

The technology for the collection and analysis of plant‐emitted volatiles for understanding chemical cues of plant–plant, plant–insect or plant–microbe interactions has increased over the years. Consequently, the in situ collection, analysis and identification of volatiles are considered integral to elucidation of complex plant communications. Due to the complexity and range of emissions the conditions for consistent emission of volatiles are difficult to standardise.

Objective

To discuss: evaluation of emitted volatile metabolites as a means of screening potential target‐ and non‐target weeds/plants for insect biological control agents; plant volatile metabolomics to analyse resultant data; importance of considering volatiles from damaged plants; and use of a database for reporting experimental conditions and results.

Method

Recent literature relating to plant volatiles and plant volatile metabolomics are summarised to provide a basic understanding of how metabolomics can be applied to the study of plant volatiles.

Results

An overview of plant secondary metabolites, plant volatile metabolomics, analysis of plant volatile metabolomics data and the subsequent input into a database, the roles of plant volatiles, volatile emission as a function of treatment, and the application of plant volatile metabolomics to biological control of invasive weeds.

Conclusion

It is recommended that in addition to a non‐damaged treatment, plants be damaged prior to collecting volatiles to provide the greatest diversity of odours. For the model system provided, optimal volatile emission occurred when the leaf was punctured with a needle. Results stored in a database should include basic environmental conditions or treatments. Copyright © 2013 John Wiley & Sons, Ltd.
Dolutegravir: A New Integrase Strand Transfer Inhibitor for the Treatment of HIV
Authors: Shah Bhavik M. , Schafer Jason J. , DeSimone Joseph A.
Published: December 2013

The first two integrase strand transfer inhibitors (INSTIs) approved for treatment of patients infected with human immunodeficiency virus (HIV) were raltegravir and elvitegravir. Both raltegravir and elvitegravir are now guideline‐preferred agents as part of an antiretroviral regimen for treatment‐naive patients. However, raltegravir is dosed twice/day. Elvitegravir is available in a single‐tablet regimen and dosed once/day because it is administered with the pharmacokinetic booster cobicistat, a potent CYP3A4 inhibitor that can lead to clinically significant drug–drug interactions. In addition, raltegravir and elvitegravir have a low genetic barrier to resistance and are associated with cross‐resistance. Dolutegravir is a new‐generation INSTI administered once/day without a pharmacokinetic booster and can be coformulated in a single‐tablet regimen. Phase III studies have demonstrated the efficacy and safety of dolutegravir for treatment‐naive and treatment‐experienced patients. Compared with other INSTIs, dolutegravir has a higher genetic barrier to resistance. Dolutegravir was approved by the U.S. Food and Drug Administration in August 2013 and joins raltegravir and elvitegravir as guideline‐preferred agents for the management for HIV‐infected treatment‐naive patients.
Azopolymer‐based micro‐ and nanopatterning for photonic applications
Authors: Priimagi Arri , Shevchenko Andriy
Published: December 2013

Azopolymers comprise a unique materials platform, in which the photoisomerization reaction of azobenzene molecules can induce substantial material motions at molecular, mesoscopic, and even macroscopic length scales. In particular, amorphous azopolymer films can form stable surface relief patterns upon exposure to interfering light. This allows obtaining large‐area periodic micro‐ and nanostructures in a remarkably simple way. Herein, recent progress in the development of azopolymer‐based surface‐patterning techniques for photonic applications is reviewed. Starting with a thin azopolymer layer, one can create a variety of photonic elements, such as diffraction gratings, microlens arrays, plasmonic sensors, antireflection coatings, and nanostructured light‐polarization converters, either by using the azopolymer surface patterns themselves as optical elements or by utilizing them to microstructure or nanostructure other materials. Both of these domains are covered, with the aim of triggering further research in this fascinating field of science and technology that is far from being harnessed. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014, 52, 163–182
A modified dynamic surface approach for control of nonlinear systems with unknown input dead zone
Authors: Sun Guofa , Ren Xuemei , Chen Qiang , Li Dongwu
Published: December 2013

This paper focuses on the robust output precise tracking control problem of uncertain nonlinear systems in pure‐feedback form with unknown input dead zone. By designing an extended state observer, the states unmeasurable problem in traditional feedback control is solved, and the lumped uncertainty, which is caused by system unknown functions and input dead zone, is estimated. In order to apply separation principle, finite‐time extended state observer is designed to obtain system states and estimate the lumped uncertainty. Then, by introducing tracking differentiator, a modified dynamic surface control approach is developed to eliminate the ‘explosion of complexity’ problem and guarantee the tracking performance of system output. Because tracking differentiator is a fast precise signal filter, the closed‐loop control performance is significantly improved when it is used in dynamic surface control instead of first‐order filters. The L ∞  stability of the whole closed‐loop system, which guarantees both the transient and steady‐state performance, is shown by the Lyapunov method and initialization technique. Numerical and experiment examples are performed to illustrate our proposed control scheme with satisfactory results. Copyright © 2013 John Wiley & Sons, Ltd.
Robust global uniform asymptotic stabilization of underactuated surface vessels with unknown model parameters
Authors: Xie Wenjing , Ma Baoli
Published: December 2013

The full‐state stabilization scheme is proposed for the control of an underactuated surface vessel with unknown modeling parameters. By knowing only the upper/lower bounds of model parameters, the designed controller is the first one able to globally uniformly asymptotically stabilize all the states of the vessel to zero. The virtual surge velocity control law is first derived, which makes the Lyapunov function at the kinematic level non‐increasing, irrelevant to the yaw velocity, leaving a freedom for choosing the virtual yaw velocity control law to stabilize the other state variables. After finishing the design of virtual velocity law, the back‐stepping approach and the Lyapunov redesign technique are combined to obtain the actual force/torque control law despite parameter uncertainties. Simulation examples are given to illustrate the effectiveness of the proposed control law, showing that all the states and the control inputs are globally uniformly asymptotically convergent to zero under parameter uncertainties and are globally bounded under unknown external bounded disturbances. Copyright © 2013 John Wiley & Sons, Ltd.