bluuebunny/crossref_metadata_2025 huggingface dataset:
Size‐, Shape‐ and Composition‐Dependent Alloying Ability of Bimetallic Nanoparticles
Authors: Xiong Shiyun , Qi Weihong , Huang Baiyun , Wang Mingpu
Published: April 2011

Based on the surface‐area‐difference model, the formation enthalpies and the formation Gibbs free energies of bimetallic nanoparticles are calculated by considering size and shape effects. Composition–critical size diagrams were graphed for bulk immiscible bimetallic nanoparticles with the developed model. The results reveal that both the formation enthalpy and formation Gibbs free energy decrease with the decrease of particle size. The effect of rising temperature is similar to the diminishing of particle size on reducing the formation Gibbs free energy. Contrary to the positive formation enthalpy of the bulk immiscible system, a negative formation enthalpy is obtained when the particles are smaller than a critical size. With the decrease of size, the alloying process first takes place in the dilute solute regions, then broadens to the dense solute regions and finally, particles with all compositions can be alloyed. The composition–critical size diagram is classified into three regions by the critical size curves with shape factors of 1 and 1.49, that is, the non‐alloying region, alloying region and possible alloying region. The model predictions correspond well with experimental evidences and computer simulation results for Cu–Ag, Au–Ni, Ag–Pt and Au–Pt systems.
Palliative care and withholding and withdrawing dialysis
Authors: Holley Jean L.
Published: April 2011

The aging dialysis population, with its decreasing functional status, the high mortality of end‐stage renal disease (ESRD), and the rise of palliative medicine as a specialty have all served to promote the importance of end‐of‐life care for ESRD patients. Even though nephrologists have an increased understanding of the issues involved in ESRD end‐of‐life care, most individuals working in dialysis know of a case in which it felt as if “the dead were being dia‐lyzed.” An increased effort to focus on palliative care issues in ESRD, especially advance care planning, may serve to reduce the frequency of such cases.
Home dialysis: A Dutch perspective
Authors: Boeschoten Elisabeth W. , Michels Wieneke M.
Published: April 2011

For patients with end‐stage renal disease who are not (yet) eligible for renal transplantation, treatment with dialy‐sis is mandatory for survival. Home dialysis modalities (home hemodialysis or peritoneal dialysis) offer patients more ﬂexibility compared with in‐center treatment and have been advocated as the ﬁrst choice in clinically stable patients. However, despite encouraging developments in dialysis systems that make the procedure easier, in many countries the proportion of patients using home dialysis, especially peritoneal dialysis, is decreasing. In Europe this decrease is most pronounced in the Netherlands and the United Kingdom. This evolution cannot be motivated by an inferiority of home dialysis modalities compared with in‐center treatment, as all these modalities have been shown to generate similar results. Other, often non‐medical, factors (such as reimbursement, social and logistic issues, and the experience of physicians and nurses with home dialysis) seem to be responsible for this development.
Developmental mechanisms for the generation of telencephalic interneurons
Authors: Corbin Joshua G. , Butt Simon J.B.
Published: April 2011

Interneurons, which release the neurotransmitter γ‐aminobutyric acid (GABA), are the major inhibitory cells of the central nervous system (CNS). Despite comprising only 20–30% of the cerebral cortical neuronal population, these cells play an essential and powerful role in modulating the electrical activity of the excitatory pyramidal cells onto which they synapse. Although interneurons are present in all regions of the mature telencephalon, during embryogenesis these cells are generated in specific compartments of the ventral (subpallial) telencephalon known as ganglionic eminences. To reach their final destinations in the mature brain, immature interneurons migrate from the ganglionic eminences to developing telencephalic structures that are both near and far from their site of origin. The specification and migration of these cells is a complex but precisely orchestrated process that is regulated by a combination of intrinsic and extrinsic signals. The final outcome of which is the wiring together of excitatory and inhibitory neurons that were born in separate regions of the developing telencephalon. Disruption of any aspect of this sequence of events during development, either from an environmental insult or due to genetic mutations, can have devastating consequences on normal brain function. © 2011 Wiley Periodicals, Inc. Develop Neurobiol 71: 710–732, 2011
Fgfr3 regulates development of the caudal telencephalon
Authors: Moldrich Randal X. , Mezzera Cecilia , Holmes William M. , Goda Sailaja , Brookfield Sam J. , Rankin Alastair J. , Barr Emily , Kurniawan Nyoman , Dewar Deborah , Richards Linda J. , López‐Bendito Guillermina , Iwata Tomoko
Published: April 2011

The fibroblast growth factor receptor 3 (Fgfr3) is expressed in a rostrallow to caudalhigh gradient in the developing cerebral cortex. Therefore, we hypothesized that Fgfr3 contributes to the correct morphology and connectivity of the caudal cortex. Overall, the forebrain structures appeared normal in Fgfr3−/− mice. However, cortical and hippocampal volumes were reduced by 26.7% and 16.3%, respectively. Hypoplasia was particularly evident in the caudo‐ventral region of the telencephalon where proliferation was mildly decreased at embryonic day 18.5. Dysplasia of GABAergic neurons in the amygdala and piriform cortex was seen following GAD67 immunohistochemistry. Dye‐tracing studies and diffusion magnetic resonance imaging and tractography detected a subtle thalamocortical tract deficit, and significant decreases in the stria terminalis and lateral arms of the anterior commissure. These results indicate the subtle role of Fgfr3 in formation of caudal regions of the telencephalon affecting some brain projections. Developmental Dynamics 240:1586–1599, 2011. © 2011 Wiley‐Liss, Inc.
Determination of Nitrophenols in Drinking and River Water by Differential Pulse Voltammetry at Boron‐Doped Diamond Film Electrode
Authors: Musilová Jana , Barek Jiří , Pecková Karolina
Published: April 2011

A differential pulse voltammetric method was developed for the determination of 2‐nitrophenol, 4‐nitrophenol and 2,4‐dinitrophenol at a boron‐doped diamond film electrode using electrochemical reduction and of 4‐nitrophenol and 2,4‐dinitrophenol using electrochemical oxidation. The method was successfully applied for the direct determination of these compounds in drinking and river water in the concentration range from 4×10−7 to 2×10−5 mol L−1. To improve the limit of quantification, a preconcentration by solid phase extraction from 100 mL and 1000 mL of water samples was used with limit of determination around 2×10−8 and 2×10−7 mol L−1, respectively.
Building a dynamic electro‐mechanical model for the Pacific AC intertie using distributed synchrophasor measurements
Authors: Chakrabortty Aranya , Salazar Armando
Published: April 2011

In this paper, we present a novel algorithm for constructing simplified interarea models of large power networks by using dynamic measurements available from phasor measurement units (PMUs) installed at specific points on the transmission line. Our example of study in this paper is a widely encountered realistic system, namely the Pacific AC intertie, which closely resembles a star‐connected three‐area power system. We derive analytical results showing how the voltage, phase angle, and frequency oscillations at different buses on the transfer path of this intertie can be used to estimate the essential parameters of the three‐machine equivalent model of this three‐area system. We illustrate the results with actual disturbance event data from the Western Electricity Coordinating Council. Copyright © 2011 John Wiley & Sons, Ltd.
Exploring Survey‐Based Inflation Forecasts
Authors: Gil‐Alana Luis , Moreno Antonio , Pérez de Gracia Fernando
Published: April 2011

This paper first shows that survey‐based expectations (SBE) outperform standard time series models in US quarterly inflation out‐of‐sample prediction and that the term structure of survey‐based inflation forecasts has predictive power over the path of future inflation changes. It then proposes some empirical explanations for the forecasting success of survey‐based inflation expectations. We show that SBE pool a large amount of heterogeneous information on inflation expectations and react more flexibly and accurately to macro conditions both contemporaneously and dynamically. We illustrate the flexibility of SBE forecasts in the context of the 2008 financial crisis. Copyright © 2011 John Wiley & Sons, Ltd.
Sox10 is required for Schwann‐cell homeostasis and myelin maintenance in the adult peripheral nerve
Authors: Bremer Magdalena , Fröb Franziska , Kichko Tatjana , Reeh Peter , Tamm Ernst R. , Suter Ueli , Wegner Michael
Published: April 2011

The transcription factor Sox10 functions during multiple consecutive stages of Schwann‐cell development in the peripheral nervous system (PNS). Although Sox10 continues to be expressed in mature Schwann cells of the adult peripheral nerve, it is currently unclear whether it is still functional. Here, we used a genetic strategy to selectively delete Sox10 in glia of adult mice in a tamoxifen‐dependent manner. The tamoxifen‐treated mice developed a severe peripheral neuropathy that was associated with dramatic alterations in peripheral nerve structure and function. Demyelination and axonal degeneration were as much evident as signs of neuroinflammation. Compound action potentials exhibited pathophysiological alterations. Sox10‐deleted Schwann cells persisted in the peripheral nerve, but did not exhibit a mature, myelinating phenotype arguing that Sox10 is rather required for differentiation and maintenance of the differentiated state than for survival. Our report is the first evidence that Sox10 is still essentially required for Schwann‐cell function in the adult PNS and establishes a useful model in which to study human peripheral neuropathies. © 2011 Wiley‐Liss, Inc.
Occurrence and formation of endogenous histidine hexa‐coordination in cold‐adapted hemoglobins
Authors: Merlino Antonello , Howes Barry D. , Prisco Guido di , Verde Cinzia , Smulevich Giulietta , Mazzarella Lelio , Vergara Alessandro
Published: April 2011

Spectroscopic and crystallographic evidence of endogenous (His) ligation at the sixth coordination site of the heme iron has been reported for monomeric, dimeric, and tetrameric hemoglobins (Hbs) in both ferrous (hemochrome) and ferric (hemichrome) oxidation states. In particular, the ferric bis‐ histidyl adduct represents a common accessible ordered state for the β chains of all tetrameric Hbs isolated from Antarctic and sub‐Antarctic fish. Indeed, the crystal structures of known tetrameric Hbs in the bis‐His state are characterized by a different binding state of the α and β chains. An overall analysis of the bis‐histidyl adduct of globin structures deposited in the Protein Data Bank reveals a marked difference between hemichromes in tetrameric Hbs compared to monomeric/dimeric Hbs. Herein, we review the structural, spectroscopic and stability features of hemichromes in tetrameric Antarctic fish Hbs. The role of bis‐histidyl adducts is also addressed in a more evolutionary context alongside the concept of its potential physiological role. © 2011 IUBMB IUBMB Life, 63(5): 295–303, 2011
Polymerization of hemoglobins in Arctic fish: Lycodes reticulatus and Gadus morhua
Authors: Riccio Alessia , Mangiapia Gaetano , Giordano Daniela , Flagiello Angela , Tedesco Roberta , Bruno Stefano , Vergara Alessandro , Mazzarella Lelio , di Prisco Guido , Pucci Piero , Paduano Luigi , Verde Cinzia
Published: April 2011

In vitro, and possibly in vivo, hemoglobin polymerization and red blood cell sickling appear to be widespread in codfish. In this article, we show that the hemoglobins of the two Arctic fish Lycodes reticulatus and Gadus morhua also have the tendency to polymerize, as monitored by dynamic light scattering experiments. The elucidation of the primary structure of the single hemoglobin of the zoarcid L. reticulatus shows the presence of a large number of cysteyl residues in α and β chains. Their role in eliciting the ability to produce polymers was also addressed by MALDI‐TOF and TOF‐TOF mass spectrometry. The G.morhua globins are also rich in Cys, but unlike in L. reticulatus, polymerization does not seem to be disulfide driven. The widespread occurrence of the polymerization phenomenon displayed by hemoglobins of Arctic fish supports the hypothesis that this feature may bea response to stressful environmental conditions. © 2011 IUBMB IUBMB Life, 63(5): 346–354, 2011
Reaming debris as a novel source of autologous bone to enhance healing of bone defects
Authors: Bakker Astrid D. , Kroeze Robert Jan , Korstjens Clara , de Kleine Ruben H. , Frölke Jan Paul M. , Klein‐Nulend Jenneke
Published: April 2011

Reaming debris is formed when bone defects are stabilized with an intramedullary nail, and contains viable osteoblast‐like cells and growth factors, and might thus act as a natural osteoinductive scaffold. The advantage of using reaming debris over stem cells or autologous bone for healing bone defects is that no extra surgery is needed to obtain the material. To assess the clinical feasibility of using reaming debris to enhance bone healing, we investigated whether reaming debris enhances the healing rate of a bone defect in sheep tibia, compared to an empty gap. As golden standard the defect was filled with iliac crest bone. Bones treated with iliac crest bone and reaming debris showed larger callus volume, increased bone volume, and decreased cartilage volume in the fracture gap, and increased torsional toughness compared to the empty gap group at 3 weeks postoperative. In addition, bones treated with reaming debris showed increased torsional stiffness at 6 weeks postoperatively compared to the empty defect group, while bending stiffness was marginally increased. These results indicate that reaming debris could serve as an excellent alternative to iliac crest bone for speeding up the healing process in bone defects that are treated with an intramedullary nail. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 2011.
Alkali metal atom‐aromatic ring: A novel interaction mode realizes large first hyperpolarizabilities of M@AR (M = Li, Na, and K, AR = pyrrole, indole, thiophene, and benzene)
Authors: Yu Guangtao , Huang Xu‐Ri , Chen Wei , Sun Chia‐Chung
Published: April 2011

Several new electride compounds M@pyrrole (M = Li, Na, and K), Li@AR (AR = indole, thiophene, and benzene), Li@tryptophan and Li@serotonin were designed and investigated, which exhibit considerably large first hyperpolarizabilities (β0) (6705, 1116, 11399, 5781, 4808, 1536, 8106, and 9389 au, respectively) by comparison with their corresponding sole molecules pyrrole (β0 = 30 au), indole (104 au), thiophene (6 au), benzene (0 au), tryptophan (159 au) and serotonin (151 au), respectively. The computational results revealed that the interaction of the alkali metal atom with π‐conjugated aromatic ring (AR) is one effectively new approach to produce diffuse excess electron to get a large β0 value, which is advantageous for the design of the novel high‐performance NLO materials with π‐conjugated AR: alkali metal atoms doped nanomaterials and biomolecules. © 2011 Wiley Periodicals, Inc. J Comput Chem 2011
EDF phytolith analysis from Heying site, southeast China, Shang‐Zhou dynasties
Authors: Wu Yan , Wang Changsui
Published: April 2011

In this article, we propose to make morphotypological phytolith analysis of Heying site during Shang‐Zhou Period by two methods: measuring based on extended depth of focus (EDF) image and measuring directly under microscope, and then compare their results. The comparison shows that the results by these two methods match each other for paleoenvironmental and agricultural analysis. Results of two methods show that Heying site's environment should be warm and moist based on the predominance of some specific phytolith assemblages. The phytolith morpho‐types originated from crop plants also indicates that rice planting was the mainstay agricultural economy. In comparison, the morphotypological analysis method based on EDF image took only about 1/10 the time as the original method by directly measuring under microscope. Thus, we can process more samples and make a more thorough and systematic morphotypological phytolith analysis with the same amount of time. Furthermore, the constructed EDF image can also be archived for future examination and for education. The above experiments indicate that the morphotypological analysis method based on EDF image is very promising for phytolith analysis. Microsc. Res. Tech. 2011. © 2011 Wiley Periodicals, Inc.
Synthesis, insecticidal activities, and molecular docking studies of 1,5‐disubstituted‐1,3,5‐hexahydrotriazine‐2‐(N‐nitro)imines
Authors: Sun Chuan‐Wen , Wang Hai‐Feng , Zhu Jun , Yang Ding‐Rong , Jin Jia , Xing Jia‐Hua
Published: April 2011

A series of novel neonicotinoids analogs were designed by modifying the pharmacophore of imidacloprid to 1,3,5‐hexahydrotriazine conjugated to nitroimine (NNO2) and introducing the phenyl or arylmethyl at the 5‐position, and their insecticidal activities were evaluated. Introducing a heterocyclic methyl at 5‐position increased the insecticidal activities, whereas other phenyl, phenylmethyl or phenylethyl substituents were unfavorable to activities. Molecular docking study was also performed to clarify the interactions of the most potent analog 1‐((6‐chloropyridin‐3‐yl)methyl)‐5‐(3‐pyridylmethyl)‐1,3,5‐hexahydrotriazine‐2‐(N‐nitro) imine (7s) with the target nicotinic acetylcholine receptor, which explained the structure‐activity relationships observed in vitro, and revealed further possibilities for insecticide development. J. Heterocyclic Chem., (2011).
Synthesis of dispiro[oxindole‐pyrrolidine]‐thiazolo[3,2‐a][1,3,5]triazines by 1,3‐dipolar cycloaddition
Authors: Li Xiaofang , Li Zhikui , Zheng Aiting , Li Guobin , Yu Xianyong , Yi Pinggui
Published: April 2011

The 1,3‐dipolar cycloaddition of an azomethine ylide generated by a decarboxylative route from sarcosine and isatin to 7‐arylmethylidene‐3‐aryl‐3,4‐dihydro‐2H‐thiazolo[3,2‐a][1,3,5]triazin‐6(7H)‐ones afforded novel dispiro[oxindole‐pyrrolidine]‐thiazolo[3,2‐a][1,3,5]triazines in moderate yields. The structures of the products were determined and characterized thoroughly by NMR, MS, IR, and elemental analysis. The results of experiment indicated that this 1,3‐dipolar cycloaddition proceeded with high stereoselectivity and regioselectivity. J. Heterocyclic Chem., (2011).
Extraction and preconcentration technique for triazole pesticides from cow milk using dispersive liquid–liquid microextraction followed by GC‐FID and GC‐MS determinations
Authors: Farajzadeh Mir Ali , Djozan Djavanshir , Mogaddam M. R. Afshar , Bamorowat Mehdi
Published: April 2011

A simple and rapid dispersive liquid–liquid microextraction (DLLME) technique coupled with gas chromatography‐flame ionization detection (GC‐FID) and gas chromatography‐mass spectrometry (GC‐MS) was developed for the extraction, preconcentration, and analysis of triazole pesticides (penconazole, hexaconazole, tebuconazole, triticonazole, and difenoconazole) in cow milk samples. Initially to 5 mL milk sample, NaCl and acetonitrile were added as salting‐out agent and extraction solvent, respectively. After manual shaking, the mixture was centrifuged. In the presence of sodium chloride, a two‐phase system was formed: upper phase, acetonitrile containing triazole pesticides and lower phase, aqueous phase containing soluble compounds and the precipitated proteins. After the extraction of pesticides from milk, a portion of supernatant phase (acetonitrile) was removed, mixed with chloroform at microliter level and rapidly injected by syringe into 5 mL distilled water. In this process, triazole pesticides were extracted into fine droplets of chloroform (as extraction solvent). After centrifugation, the fine droplets of chloroform were sedimented in bottom of the conical test tube. Finally, GC‐FID and GC‐MS were used for the separation and determination of analytes in the sedimented phase. Some important parameters like type of solvent for extraction of pesticides from milk, salt amount, the volume of extraction solvent, etc., which affect the extraction efficiency, were completely studied. Under the optimum conditions, enrichment factors were in the range of 156–380. The linear ranges of calibration curves were wide and limits of detection (LODs) and limits of quantification (LOQs) were between 4–58 and 13–180 μg/L, respectively. This method is very simple and rapid, requiring <15 min for sample preparation.
Development of a rapid and convenient method to separate eight ginsenosides from Panax ginseng by high‐speed counter‐current chromatography coupled with evaporative light scattering detection
Authors: Shehzad Omer , Jin Ha In , Park Youmie , Wan Ha Young , Shik Kim Yeong
Published: April 2011

Ginsenosides exhibit diverse biological activities and are major well‐known components isolated from the radix of Panax ginseng C.A. Meyer. In the present work, a rapid and facile method for the separation and purification of eight ginsenosides from P. ginseng by high‐speed counter‐current chromatography coupled with evaporative light scattering detector (HSCCC‐ELSD) was successfully developed. The crude samples for HSCCC separation were first purified from ginseng extract using a macroporous resin; the extract was loaded onto a Diaion‐HP20 column and fractionated by methanol and water gradient elution. The ginsenosides‐protopanaxadiol (PPD) and protopanaxatriol (PPT) fractions were subsequently eluted with 65 and 80% methanol and water gradient elution, respectively. Furthermore, these two fractions were separated by HSCCC‐ELSD. The two‐phase solvent system used for separation was composed of chloroform/methanol/water/isopropanol at a volume ratio of 4:3:2:1. Each fraction obtained was collected and dried, yielding the following eight ginsenosides: Rg1, Re, Rf, Rh1, Rb1, Rc Rb2 and Rd. The purity of these ginsenosides was greater than 97% as assessed by HPLC‐ELSD, and their structures were characterized by electrospray‐ionization mass spectrometry (ESI‐MS) and nuclear magnetic resonance spectroscopy. This is the first report regarding the separation of the ginsenosides Rh1, Rb2 and Rc from P. ginseng by HSCCC.
Drugs of abuse and their metabolites in waste and surface waters by liquid chromatography‐tandem mass spectrometry
Authors: Pedrouzo Marta , Borrull Francesc , Pocurull Eva , Marcé Rosa Maria
Published: April 2011

A solid‐phase extraction and liquid chromatography‐tandem mass spectrometry (SPE/LC‐MS‐MS) method was developed and validated for the simultaneous determination of nicotine, five drugs of abuse (morphine, cocaine, codeine, methadone, and 2‐ethylidene‐1,5‐dimethyl‐3,3‐diphenylpyrrolidine) and four metabolites (dihydrocodeine, 6‐acetylmorphine, 11‐nor‐carboxy‐Δ9‐tetrahydrocannabinol, and benzoylecgonine) in water samples. A Fused‐Core™ particle column was used as an alternative to sub‐2‐μm particles in chromatographic separations to work with low backpressures and high efficiencies in short analysis times. Drugs were extracted from waste and surface water with SPE using Oasis MCX cartridges. Electrospray (ESI) in positive and negative mode and tandem MS selected reaction monitoring mode were used for identification and quantification. Calibration by linear regression analysis with deuterated internal standards was used to compensate the matrix effects. Limits of detection were found as low as 0.5–1 ng/L (surface water) and 1–50 ng/L (wastewater). The method was applied to the analysis of different kinds of samples. Wastewater from a sewage treatment plant was collected from three sampling points (after primary, secondary, and tertiary treatments) for a week. The analysis of the samples revealed a significant presence of these drugs in samples from primary treatments, where maximum concentrations of nicotine (1105 ng/L) and benzoylecgonine (3336 ng/L) were found. Most of the compounds showed values between <LOQ and 52 ng/L after tertiary treatment. When surface waters from the Ebro River were analyzed, only benzoylecgonine showed levels between 19 and 35 ng/L.
Recent advances in silica‐based monoliths: Preparations, characterizations and applications
Authors: Ghanem Ashraf , Ikegami Tohru
Published: April 2011

This mini‐review describes recent progress (2009–2010) in the field of silica‐based monolith with special emphasis on the preparation, characterization and applications.
Pretreatment swallowing assessment in head and neck cancer patients
Authors: Starmer Heather , Gourin Christine , Lua Lannah L. , Burkhead Lori
Published: April 2011

Objectives/Hypothesis:

To discuss patient variables associated with swallowing dysfunction in head and neck cancer (HNCA) patients prior to intervention.

Study Design:

Prospective, multi‐institutional cohort study.

Methods:

All patients included had newly diagnosed head and neck malignancies. Patients undergoing instrumental swallowing evaluations prior to oncologic management were included for analysis. Pretreatment Penetration Aspiration Scores (PAS) were analyzed by primary tumor site, tumor stage, and standard demographic variables.

Results:

The final study sample was comprised of 204 consecutive individuals with newly diagnosed HNCA. Patients with advanced primary tumor (T) stage laryngeal/hypopharyngeal tumors had higher mean PAS scores (5.18) in contrast to early stage larynx/hypopharynx (1.93), advanced stage oral cavity/oropharynx (2.24), and early stage oral cavity/oropharynx (1.54, P < .0001), indicative of poorer function. Age, race, and sex were not associated with PAS scores. Multivariate logistic regression revealed significantly poorer PAS scores in patients with advanced primary tumors (odds ration [OR] = 3.83, 95% confidence interval [CI], 1.84‐8.00, P < .0001) and laryngeal/hypopharyngeal primary site disease (OR = 3.04, 95% CI, 1.41‐6.54, P = .004), after controlling for all other variables.

Conclusions:

This series demonstrates that swallowing dysfunction in high‐risk patients may be present in the pretreatment state and should be considered when determining candidacy for organ preservation modalities. These data highlight the importance of instrumental swallowing evaluations prior to intervention, particularly for those individuals with advanced stage and/or laryngeal/hypopharyngeal tumors.
Cell Specific Peptide‐Conjugated Polysaccharide Nanogels for Protein Delivery
Authors: Shimoda Asako , Sawada Shin‐ichi , Akiyoshi Kazunari
Published: April 2011

A cell specific peptide (Arg‐Gly‐Asp; RGD)‐modified nanogel was prepared and evaluated for its potential to act as a protein delivery carrier. A bovine serum albumin (BSA)/RGD‐modified nanogel complex was efficiently internalized into cells through integrin‐mediated endocytosis. Endosomal escape of the RGD‐modified nanogel was observed after 24 h incubation. The nanogel proved useful for targeted protein delivery.

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Microstructure Evolution and Dynamic Stages of Cold‐Crystallized Poly(trimethylene terephthalate) Revealed by Synchronous Fluorescence Scanning
Authors: Luo Wei‐ang , Liao Zhengfu , Yang Jin , Chen Xudong , Zheng Xindan , Mai Kancheng
Published: April 2011

The nonisothermal cold crystallization of PTT films is studied by means of SFS. Detailed information on the glass transition and different stages of crystallization is presented. Crystallization kinetics and activation energy obtained from SFS are in good agreement with values determined from DSC. The results show that SFS is a simple, sensitive, selective in situ method for determining structure/dynamics relationships during relaxation and crystallization of polymers. SFS overcomes the drawbacks of conventional methods and combines the advantages of resonance light scattering (high sensitivity) and fluorescence spectroscopy (a structural technique). It can provide detailed information about structural evolution at molecular level, in particular about cohesive entanglement of polymer chains.

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Synthesis of Heterobifunctional Hyperbranched Polyethylenes Tethered with Dual Acryloyl and 2‐Bromoisobutyryl Functionalities via One‐Pot Chain‐Walking Terpolymerization
Authors: Xu Yuanqing , Campeau Patrick , Ye Zhibin
Published: April 2011

A one‐step synthesis of heterobifunctional hyperbranched polyethylenes covalently tethered with dual acryloyl and 2‐bromoisobutyryl functionalities at controllable contents is reported. It is achieved in one pot by chain‐walking terpolymerization of ethylene with two functional acrylate comonomers, 1,6‐hexanediol diacrylate and 2‐(2‐bromoisobutyryloxy) ethyl acrylate. The unique chain‐walking mechanism renders the hyperbranched polymer chain topology and its remarkable capability in incorporating acrylate comonomers enables the incorporation of both comonomers to give two valuable functionalities. The two comonomers exhibit nearly equal vinyl reactivity and are incorporated independently in the terpolymerization with their molar contents controlled by adjusting the comonomer feed concentrations.

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When referring physicians and researchers disagree on equipoise: the TOTAL trial experience
Authors: Rodrigues H. C. M. L. , Deprest J. , Berg P. P. v. d.
Published: April 2011

Objective

In this article, we reflect on whether randomized controlled trials (RCTs) are adequate for the clinical evaluation of maternal–fetal surgery for congenital diaphragmatic hernia (CDH), focusing on the role of patients' preferences in the setting up of research protocols, on the requirement of equipoise and on the concept of therapeutic misconception (TM).

Method

We describe the conception and setting up of the tracheal occlusion (TO) to accelerate lung growth trial and analyze the ethical dilemmas faced by the research team during that time.

Results

Depending on the view adopted regarding the scope of equipoise, there are two ways of dealing with patient's preferences concerning fetoscopic endoluminal TO and expectant management during pregnancy for CDH.

Conclusion

The solution adopted for fetoscopic endoluminal tracheal occlusion (FETO) is justified by the extended period of time it has been available to patients before the start of the RCT. Strong patient and referring physician preferences do not entail a right to have FETO, since it is a procedure of yet unproven efficacy and safety. In the future, to avoid the dilemmas posed by the TM and in name of the right of future generations of patients to have access to treatment of proven safety and efficacy, researchers must be able to plan RCT in due time. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation and characterization of PET/clay nanocomposites by melt compounding
Authors: Ghasemi Hesam , Carreau Pierre J. , Kamal Musa R. , Uribe‐Calderon Jorge
Published: April 2011

Poly(ethylene terephthalate) (PET) nanocomposites were prepared via melt compounding using a twin‐screw extruder at 265°C. Three different types of organomodified clay were melt compounded with PET: a commercial ammonium‐modified silicate clay (Cloisite 30B) and specially prepared thermally stable phosphonium‐ and imidazolium‐modified montmorillonites. X‐ray diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and thermogravimetric analysis were used to characterize and evaluate the quality of the nanocomposites. To obtain quantitative evaluation of the dispersion level in nanocomposites, statistical analysis of TEM micrographs was performed using a dispersion parameter, D0.1, based on free‐path spacing measurements. The results showed that the ammonium surfactant yielded the best intercalation results in nanocomposites. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Common lessons learned from an analysis of multiple case histories
Authors: Yang Xiaole , Dinh Linh T.T. , Castellanos Diana , Amado Carmen H. Osorio , Ng Dedy , Mannan M. Sam
Published: April 2011

In recent years there has been increased emphasis on process safety as a result of major chemical incidents involving gas releases, major explosions, and environmental incidents. Spending some time to fix our eyes on the historical catastrophes of industrial processes is necessary for process safety improvement. While each case history presents an important foundation for understanding, identifying, and eliminating root causes, to prevent recurrence of these incidents there is a need to identify the common lessons learned. Root causes are usually deficiencies in safety management systems, but can be any factor that would have prevented the incident if that factor had not occurred. In this article, multiple case histories were analyzed to understand the common similarities between process incidents. The objective of this article is to focus on learning some common lessons from the historical incidents in order to prevent recurrences of similar incidents. Ten important lessons were identified and are described in this article. © 2011 American Institute of Chemical Engineers Process Saf Prog 2011
Use of a nonlinear pseudo‐relative humidity variable in a multivariate formulation of moisture analysis
Authors: Gustafsson N. , Thorsteinsson S. , Stengel M. , Hólm E.
Published: April 2011

We present a reformulation of the humidity part of the HIRLAM (HIgh‐Resolution Limited‐Area Model) variational data assimilation. The purpose is to rectify some of the shortcomings of the present formulation which uses specific humidity, q, as an assimilation control variable with homogeneous and static covariances. One problem is that specific humidity forecast errors tend to have a non‐Gaussian probability distribution, in particular near saturation and near zero humidity. In addition, the variance of the distribution tends to change in space and time due to the dependency of the water vapour saturation pressure on temperature. A modified pseudo‐relative humidity variable has been adapted to the statistical balance background constraint, including the associated moisture balance formulation. Background‐error statistics for the new moisture control variable and the moisture‐related balances were derived, taking differences between forecasts valid at the same time as a proxy for background forecast errors. The background‐error statistics were compared with the corresponding statistics for specific humidity as the moisture assimilation control variable. In connection with the nonlinearity of the change of the variable, it was noted that specified background‐error standard deviations were chosen to be substantially reduced for nearly dry and saturated states, which can raise difficulties. The impact of the new moisture assimilation control variable is illustrated with simulated observation experiments as well as data assimilation experiments using real observations, for one summer month and one winter month in a 4D‐Var assimilation cycle using two outer loop iterations in the 4D‐Var minimization. The impact of the new formulation on forecast verification scores is small and essentially neutral, while using the second outer loop in the old formulation has a small positive impact. Copyright © 2011 Royal Meteorological Society
A molecular dynamics study of sodium dodecyl sulfate‐methane system in water using the improved lennard jones formulation
Authors: Costantini Alessandro , Albertí Margarita , Fernando Pirani  , Laganà Antonio
Published: April 2011

The behavior of the sodium dodecyl sulfate (SDS)‐methane system in water has been investigated using molecular dynamics calculations performed on a local cluster as well as on the EGI‐grid distributed platform. To this end, the model adapted molecular polarizability centers for force‐fields has been adopted to provide in a reliable and suitable analytical form the various intermolecular potentials involved. Structural properties of the system have been then investigated by varying the number of water molecules solvating the SDS and the CH4 molecules. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem 112:1810–1817, 2012
Spectral representation of Hartree‐Fock exchange operator
Authors: Mysovsky Andrey S.
Published: April 2011

We report a new mathematical result: it is possible to construct a spectral representation of the two particles Coulomb potential in the form of |r − r′|−1 = ∑λλg(r) gλ(r′). We call this formula λ‐decomposition. Two special nontrivial cases of λ‐decomposition are reported together with the numerical analysis of the convergence for one of them. It is shown how λ‐decomposition allows to construct a new fast algorithm for Hartree‐Fock exchange operator calculation, in which the calculation of electron repulsion integrals (ERIs) is completely avoided. The connection between the new method and the resolution of identity and Cholesky decomposition based approaches has been established. Finally, the accuracy of ERIs evaluation within the new approach has been studied numerically. The results demonstrate that it is possible to achieve the accuracy of 10−10 for the ERIs in wide range of their orbital exponents with relatively small number of terms in λ‐decomposition. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012
Accounting for matrix effects of pesticide residue liquid chromatography/electrospray ionisation mass spectrometric determination by treatment of background mass spectra with chemometric tools
Authors: Kruve Anneli , Herodes Koit , Leito Ivo
Published: April 2011

Matrix effect (ME) – ionisation suppression or enhancement – in liquid chromatography/electrospray ionisation mass spectrometry (LC/ESI‐MS) is caused by matrix components co‐eluting with the analytes. ME has a complex and not fully understood nature. ME is also highly variable from sample to sample making it difficult to compensate for. In this work it was studied whether the background ion signals in scanned mass spectra of the LC effluent at the retention time of the analyte offer some insight into the presence and extent of matrix effect. Matrix effects for six pesticides – thiabendazole, carbendazime, methomyl, aldicarb, imazalil and methiocarb – in garlic and onion samples used in the study varied from 1% (suppression 99%) to 127% (enhancement 27%) depending on the pesticide and sample. Also standards in solvent and solvent blanks were included in the study. The ions most strongly varying from sample to sample – and therefore best describing the changes in sample composition and ME – were selected for quantification according to principal component analysis (PCA) for all six pesticides under study. These ions were used to account for ME via partial least‐squares (PLS) regression. The calibration set was constructed from 19 samples and standards and the obtained calibration function was validated with seven samples and standards. The average errors from the test set were from 0.05 to 0.27 mg/kg for carbendazim and imazalil, respectively (the respective average pesticide concentrations were 0.22 and 0.88 mg/kg). The PLS results were significantly more accurate compared to the conventional solvent calibration resulting in average errors from 0.07 to 0.69 mg/kg for carbendazime and methiocarb, respectively. Copyright © 2011 John Wiley & Sons, Ltd.
The characterisation of coumarins from selected structural classes by electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry
Authors: Smyth W. Franklin , Morgan Jason L. , O'Kane Edmund , Millar Tommy J. , Ramachandran Venkataraman N.
Published: April 2011

Electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry (ESI‐QTOF‐MS/MS) has been used for characterisation of a selection of naturally occurring and synthetic coumarins from different structural classes. The product ions, suggested in earlier studies by electrospray ionisation ion trap mass spectrometry (ESI‐MSn), are unequivocally established for the representative coumarins by virtue of accurate mass measurement. Synthetic coumarins that are unsubstituted in the heterocyclic ring give rise to a major product ion by loss of CO2, whereas those substituted in the heterocyclic ring generally undergo alternative fragmentation releasing neutral species such as ketene or methyl ketene. Naturally occurring coumarins, unsubstituted in the heterocyclic ring and substituted in the benzene ring with chains or rings of hydrocarbons and oxygen, principally fragment at the side chain releasing unsaturated hydrocarbons. The ESI‐QTOF‐MS/MS behaviour of some naturally occurring and synthetic quinolines which are structurally similar or fragment similarly are included where appropriate. Copyright © 2011 John Wiley & Sons, Ltd.
Interface analysis of Ti/Al/Ti/Au ohmic contacts with regrown n+‐GaN layers using molecular beam epitaxy
Authors: Seo Hui‐Chan , Sivaramakrishnan Shankar , Zuo Jian‐Min , Pang Liang , Krein Philip T. , Kim Kyekyoon (Kevin)
Published: April 2011

The regrowth technique of highly doped n‐type GaN layers is reliable and effective for lowering the ohmic contact resistance. The interface between metal contacts with Ti/Al/Ti/Au and regrown n+‐GaN/GaN layers were analyzed in detail with transmission electron microscopy. During the annealing process, Ti metals and N atoms diffusing from GaN layers formed TiN epitaxial layers between metal alloys and n+‐GaN layers. The orientational relationship between GaN and TiN was [1 0 0]GaN//[−1 1 0]TiN verified by nano‐beam diffraction. Al atoms diffused through the GaN layers and formed thin AlGaN phase. Al content was confirmed as 60% by high‐resolution transmission electron microscopy images. Electron energy loss spectroscopy showed that Si dopants were confined within n+‐GaN layers. These results show that in regrowth technique both TiN layers and Si dopants affect the contact properties because the formation of TiN layers can induce nitrogen vacancies from GaN, while Si‐doped GaN layers can enhance the tunneling effect through the metal contacts resulting in reduced contact resistance. Copyright © 2011 John Wiley & Sons, Ltd.
Flexible estimation of covariance function by penalized spline with application to longitudinal family data
Authors: Wang Yuanjia
Published: April 2011

Longitudinal data are routinely collected in biomedical research studies. A natural model describing longitudinal data decomposes an individual's outcome as the sum of a population mean function and random subject‐specific deviations. When parametric assumptions are too restrictive, methods modeling the population mean function and the random subject‐specific functions nonparametrically are in demand. In some applications, it is desirable to estimate a covariance function of random subject‐specific deviations. In this work, flexible yet computationally efficient methods are developed for a general class of semiparametric mixed effects models, where the functional forms of the population mean and the subject‐specific curves are unspecified. We estimate nonparametric components of the model by penalized spline (P‐spline,Biometrics2001;57:253–259), and reparameterize the random curve covariance function by a modified Cholesky decomposition (Biometrics2002;58:121–128) which allows for unconstrained estimation of a positive‐semidefinite matrix. To provide smooth estimates, we penalize roughness of fitted curves and derive closed‐form solutions in the maximization step of an EM algorithm. In addition, we present models and methods for longitudinal family data where subjects in a family are correlated and we decompose the covariance function into a subject‐level source and observation‐level source. We apply these methods to the multi‐level Framingham Heart Study data to estimate age‐specific heritability of systolic blood pressure nonparametrically. Copyright © 2011 John Wiley & Sons, Ltd.
Modelling the geographical distribution of co‐infection risk from single‐disease surveys
Authors: Schur Nadine , Gosoniu L. , Raso G. , Utzinger J. , Vounatsou P.
Published: April 2011

Background: The need to deliver interventions targeting multiple diseases in a cost‐effective manner calls for integrated disease control efforts. Consequently, maps are required that show where the risk of co‐infection is particularly high. Co‐infection risk is preferably estimated via Bayesian geostatistical multinomial modelling, using data from surveys screening for multiple infections simultaneously. However, only few surveys have collected this type of data.

Methods: Bayesian geostatistical shared component models (allowing for covariates, disease‐specific and shared spatial and non‐spatial random effects) are proposed to model the geographical distribution and burden of co‐infection risk from single‐disease surveys. The ability of the models to capture co‐infection risk is assessed on simulated data sets based on multinomial distributions assuming light‐ and heavy‐dependent diseases, and a real data set of Schistosoma mansoni–hookworm co‐infection in the region of Man, Côte d'Ivoire. The data were restructured as if obtained from single‐disease surveys. The estimated results of co‐infection risk, together with independent and multinomial model results, were compared via different validation techniques.

Results: The results showed that shared component models result in more accurate estimates of co‐infection risk than models assuming independence in settings of heavy‐dependent diseases. The shared spatial random effects are similar to the spatial co‐infection random effects of the multinomial model for heavy‐dependent data.

Conclusions: In the absence of true co‐infection data geostatistical shared component models are able to estimate the spatial patterns and burden of co‐infection risk from single‐disease survey data, especially in settings of heavy‐dependent diseases. Copyright © 2011 John Wiley & Sons, Ltd.
Role‐play virtual worlds for teaching object‐oriented design: the ViRPlay development experience
Authors: Jimenez‐Diaz Guillermo , Gonzalez‐Calero Pedro A. , Gomez‐Albarran Mercedes
Published: April 2011

The use of game technology for building virtual learning environments is intended to improve the motivation and engagement of the student, borrowing such properties from their entertaining counterparts. Nevertheless, wrapping pedagogical contents in a virtual environment is no simple achievement, and requires a rigorous process of designing and validating the metaphors and mechanics included in the virtual learning system. In this paper we describe such design process exemplified in the construction of consecutive versions of ViRPlay, a 3D role play virtual environment for teaching object‐oriented design. We show how main mechanics were transferred from experiments in the real world and how such mechanics were evolved based on empirical evaluations. Copyright © 2011 John Wiley & Sons, Ltd.
Phase and Microstructural Analysis of Hot Rolled FeNi42 Sheet, its Response in Magnetic and Mechanical Properties
Authors: Jiraskova Y. , Bursik J. , Tucek J.
Published: April 2011

Inclusions unavoidably existing in steels and consequently also in final products obtained by e.g. rolling markedly affects the physical properties. This paper is devoted to investigation of FeNi42 steel hot rolled into a sheet form. The structural and phase analysis is done by scanning electron microscopy, X‐ray diffraction, and Mössbauer spectroscopy completed by magnetic and hardness measurements. The results yield an inhomogeneous nickel distribution in the sheet resulting in a formation of the intermetallic Ni3Fe phase. A depletion of sheet surface by nickel leads to an intensive surface oxidation; its thickness increases in the direction of sheet edges. The non‐metallic oxide inclusions are concentrated predominantly at grain boundaries, which contribute to an easier cracking. The formation of Ni3Fe affects a small increase in saturation magnetization. The oxides and consequently cracks formation cause magnetic hardening as can be seen on an increase of the structurally sensitive remnant magnetization. The hard oxide inclusions evoke also the hardening of material, rise brittleness and crack liability.