bluuebunny/crossref_metadata_2025 huggingface dataset:
Pluronic F68 enhanced the conformational stability of salmon calcitonin in both aqueous solution and lyophilized solid form
Authors: Lee Ting‐Huei , Lin Shan‐Yang
Published: May 2011

The effects of different surfactants on the conformational stability and structural similarity of salmon calcitonin (sCT) in aqueous solution and lyophilized forms were investigated by using microscopic Fourier transform infrared (FTIR) spectroscopy with second‐derivative spectral analysis. Six surfactants, HCO‐60, sodium dodecyl sulfate (SDS), Tween 80, PEG 400, Pluronic 68, and F127 were selected. The sCT aqueous solution with or without different surfactants was, respectively, incubated at 40°C for up to 35 h. sCT films were casted on the CaF2 plates and IR spectra were collected as a function of incubation time. Second derivative analysis showed that the native sCT having a major α‐helical structure was gradually changed to the combination of α‐helix, random coil, and β‐sheet conformations in aqueous solution at 40°C. Similar conformational changes with delayed β‐sheet formation were obtained for sCT after co‐incubation with all the surfactants except Pluronic F68. When the native sCT was freeze‐dried alone, a marked conformational alteration was found as illustrated by a poor spectral correlation coefficient (r) value of 0.823 as compared to that of the unlyophilized native sCT. This r value was significantly deviated from 1, strongly indicating the influence of lyophilization stress on the surfactant‐free sCT. The r value for sCT after lyophilizing with HCO‐60, Pluronic F127, PEG 400, or Pluronic F68 was >0.9, suggesting the possible stabilization of these surfactants in the lyophilization process. The sCT sample after lyophilizing with Pluronic F68 showed a highest r value (>0.968), indicating the most optimal stabilization effect of Pluronic F68 for sCT sample via lyophilization. Pluronic F68 was found to be the preferential surfactant for preventing the secondary structure changes in aqueous solution at 40°C as well as in lyophilized powder. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 785‐791, 2011.
Isovaline in naturally occurring peptides: A nondestructive methodology for configurational assignment
Authors: De Zotti Marta , Biondi Barbara , Crisma Marco , Hjørringgaard Claudia U. , Berg Albrecht , Brückner Hans , Toniolo Claudio
Published: May 2011

The nonproteinogenic, Cα‐tetrasubstituted, helicogenic, chiral α‐amino acid isovaline (Iva) is remarkably spread in the biosphere. Together with its achiral, lower homolog α‐aminoisobutyric acid (Aib), it represents a characteristic marker of a class of naturally occurring peptide antibiotics, for which the acronym “peptaibiotics” became established. In these peptides, Iva occurs as the (S)‐(= L) or the (R)‐(= D) enantiomer, but peptide sequences containing both Iva enantiomers are also common. Here, we applied our recently developed 1H‐NMR method, which enables the nondestructive assignment of the configuration of each Iva residue in a peptide of known helical screw sense, to natural and synthetic peptaibiotics. Our method proved to be generally applicable and provided evidence that, in the peptaibiotic bergofungin A, the Iva12 configuration is (R) and not (S) as reported previously. Moreover, we extended our NMR method by including a 13C‐NMR parameter. A statistical analysis of the preferred main‐ and side‐chain conformations of the Iva residues in peptides, performed based on their published X‐ray diffraction structures, allowed us to provide a sound rationale to the NMR criteria exploited to establish the configuration of this amino acid. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 36–49, 2012.
Sacral nerve stimulation increases activation of the primary somatosensory cortex by anal canal stimulation in an experimental model
Authors: Griffin K M , Pickering M , O'Herlihy C , O'Connell P R , Jones J F X
Published: May 2011

Background

Sacral and posterior tibial nerve stimulation may be used to treat faecal incontinence; however, the mechanism of action is unknown. The aim of this study was to establish whether sensory activation of the cerebral cortex by anal canal stimulation was increased by peripheral neuromodulation.

Methods

A multielectrode array was positioned over the right primary somatosensory cortex of anaesthetized rats. A brief burst of electrical stimulation was applied to either the left sacral root or the left posterior tibial nerve, and evoked potentials from anal canal stimulation were signal-averaged at intervals over 1 h. At the end of the experiment, the cerebral cortex was removed and probed for polysialylated neural cell adhesion molecule (PSA-NCAM).

Results

Sacral nerve root and posterior tibial nerve stimulation significantly increased the peak amplitude of primary cortical evoked potentials by 54·0 and 45·1 per cent respectively. This change persisted throughout the period of observation. The density of PSA-NCAM-positive cells in the somatosensory cortex underlying the electrode array was increased by approximately 50 per cent in the sacral nerve-stimulated group.

Conclusion

Brief sacral neuromodulation induces profound changes in anal canal representation on the primary somatosensory cortex, providing a plausible hypothesis concerning the mechanism of action of neuromodulation in the treatment of faecal incontinence.
Randomized clinical trial of epidural, spinal or patient-controlled analgesia for patients undergoing laparoscopic colorectal surgery
Authors: Levy B F , Scott M J , Fawcett W , Fry C , Rockall T A
Published: May 2011

Background

Epidural analgesia is considered fundamental in enhanced recovery protocols (ERPs). However, its value in laparoscopic colorectal surgery is unclear. The aim of this study was to examine the effects of different analgesic regimens on outcomes following laparoscopic colorectal surgery in fluid-optimized patients treated within an ERP.

Methods

Ninety-nine patients were randomized to receive epidural, spinal or patient-controlled (PCA) analgesia. The primary endpoints were time until medically fit for discharge and length of hospital stay. Secondary endpoints included return of bowel function, pain scores, and changes in pulmonary function and quality of life.

Results

Ninety-one patients completed the study. The median length of hospital stay was 3·7 days following epidural analgesia, significantly longer than that of 2·7 and 2·8 days for spinal analgesia and PCA respectively (P = 0·002 and P < 0·001). There was also a slower return of bowel function with epidural analgesia than with spinal analgesia and PCA. Epidural analgesia did not offer better preservation of pulmonary function or quality of life, although pain scores were higher in the PCA group in the early postoperative period.

Conclusion

Many of the outcomes in the epidural analgesia group were significantly worse than those in the spinal analgesia and PCA groups, suggesting that either of these two modalities could replace epidural analgesia. Registration number: NCT 18926278 (http://www.clinicaltrials.gov).
Thyroid hormone—induced haemoglobin changes and antioxidant enzymes response in erythrocytes
Authors: Araujo A. S. R. , Seibel F. E. R. , Oliveira U. O. , Fernandes T. , Llesuy S. , Kucharski L. , Belló‐Klein A.
Published: May 2011

Thyroid hormones modulate haemoglobin and reactive oxygen species (ROS) production, leading to antioxidant changes. This study evaluated the antioxidant response to ROS in erythrocytes in hypothyroid and hyperthyroid rats. Wistar rats were divided into four groups: control; hyperthyroid (T4‐12 mg l−1 in drinking water); sham operated (simulation of thyroidectomy); and hypothyroid (thyroidectomized). Four weeks after, blood was collected and haemoglobin and T4 levels, lipid peroxidation (LPO), protein oxidation, superoxide dismutase (SOD), catalase (CAT) , glutathione S‐transferase (GST) and glutathione peroxidase (GPx) activities, and total radical antioxidant potential (TRAP) were measured. SOD, CAT and GST immunocontent was evaluated. Haemoglobin levels were increased in hyperthyroid erythrocytes. LPO and carbonyls were augmented (65% and 55%, respectively) in hyperthyroid and reduced (31% and 56%, respectively) in hypothyroid group. SOD and CAT activities have not changed, as well as CAT immunocontent. TRAP was diminished in both hyperthyroid and hypothyroid groups (36% and 37%, respectively). GST activity and immunocontent, as well as GPx activity, were increased in hyper and hypothyroid rats. The data suggest that thyroid hormone changes determine ROS concentration changes and decrease of some antioxidant defences that would lead to a compensatory answer of the GST and GPx enzymes, which could be consider as credible biomarkers. Copyright © 2011 John Wiley & Sons, Ltd.
An Efficient Route to Selective Bio‐oxidation Catalysts: an Iterative Approach Comprising Modeling, Diversification, and Screening, Based on CYP102A1
Authors: Seifert Alexander , Antonovici Mihaela , Hauer Bernhard , Pleiss Jürgen
Published: May 2011

Perillyl alcohol is the terminal hydroxylation product of the cheap and readily available terpene, limonene. It has high potential as an anti‐tumor substance, but is of limited availability. In principle, cytochrome P450 monooxygenases, such as the self‐sufficient CYP102A1, are promising catalysts for the oxidation of limonene or other inert hydrocarbons. The wild‐type enzyme converts (4R)‐limonene to four different oxidation products; however, terminal hydroxylation at the allylic C7 is not observed. Here we describe a generic strategy to engineer this widely used enzyme to hydroxylate exclusively the exposed, but chemically less reactive, primary C7 in the presence of other reactive positions. The approach presented here turns CYP102A1 into a highly selective catalyst with a shifted product spectra by successive rounds of modeling, the design of small focused libraries, and screening. In the first round a minimal CYP102A1 mutant library was rationally designed. It contained variants with improved or strongly shifted regio‐, stereo‐ and chemoselectivity, compared to wild‐type. From this library the variant with the highest perillyl alcohol ratio was fine‐tuned by two additional rounds of molecular modeling, diversification, and screening. In total only 29 variants needed to be screened to identify the triple mutant A264V/A238V/L437F that converts (4R)‐limonene to perillyl alcohol with a selectivity of 97 %. Focusing mutagenesis on a small number of relevant positions identified by computational approaches is the key for efficient screening for enzyme selectivity.
A Facile and Specific Approach to New Liquid Chromatography Adsorbents Obtained by Ionic Self‐Assembly
Authors: Qiu Hongdeng , Mallik Abul K. , Takafuji Makoto , Ihara Hirotaka
Published: May 2011

A new ionic‐liquid monomer, 1‐vinyl‐3‐octadecylimidazolium bromide ([C18VIm]Br), was prepared and polymerized on porous silica particles by means of a surface‐initiated radical chain‐transfer reaction. Further modification for functionalization was performed through the exchange of counteranions from bromide to methyl orange (MO). Two new silica–poly(octadecylimidazolium) (Sil‐PImC18) hybrid materials (Sil‐PImC18‐Br and Sil‐PImC18‐MO) were synthesized and characterized by elemental analysis, thermogravimetric analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and solid‐state 13C CP/MAS NMR spectroscopy. Sil‐PImC18‐MO presented ultra‐high shape selectivity for constrained isomers of polycyclic aromatic hydrocarbons (PAHs) both in reversed‐ and normal‐phase HPLC when used as the stationary phase. Fundamental aspects of the molecular shape selectivity were evaluated by using Standard Reference Material (SRM) 869b; the column selectivity test mixture for liquid chromatography. The impact of this phase was also demonstrated by the separation of SRM 1647e (16 priority pollutant PAHs) and several steroid isomers. Enhanced selectivity could be explained by the highly oriented arrangement between the octadecylimidazolium chain and a rigid segment of MO. These findings may open a new window of research for the design of materials used in chromatographic supports, solid extraction, catalysis, and electrolytes by simple modifications of the counterions in the poly(ionic liquid) analogous phase.
Reverse‐Flow Adsorption for Process‐Integrated Recycling of Homogeneous Transition‐Metal Catalysts
Authors: Marras Fabrizio , van Leeuwen Piet W. N. M. , Reek Joost N. H.
Published: May 2011

Supramolecular strategies, based on hydrogen bonds and ionic interactions, were investigated as tools for the recovery and recycling of homogeneous transition‐metal catalysts by using reverse‐flow adsorption (RFA) technology. The association (in solution) and adsorption (on support) of new functionalized host materials and phosphine guest ligands, functionalized with the complementary binding motifs, were fine‐tuned for the application of these materials in a RFA reactor. The RFA technology for process‐integrated recycling of homogeneous catalysts using these tailor‐made phosphine ligands and silica‐supported host materials resulted in a stable, semicontinuous catalytic system. Rhodium‐catalyzed asymmetric hydrogenation of methyl acetamidoacrylate and asymmetric hydrosilylation of acetophenone were studied as test reactions. Depending on the catalytic process the metal complex could be recycled several times without significant loss in conversion.
Pyrrolo[3,2‐h]quinazolines as Photochemotherapeutic Agents
Authors: Barraja Paola , Caracausi Libero , Diana Patrizia , Montalbano Alessandra , Carbone Anna , Salvador Alessia , Brun Paola , Castagliuolo Ignazio , Tisi Silvia , Dall'Acqua Francesco , Vedaldi Daniela , Cirrincione Girolamo
Published: May 2011

Heteroanalogues of angelicin, pyrrolo[3,2‐h]quinazolines, were synthesized with the aim of obtaining new potent photochemotherapeutic agents. Many derivatives caused a significant decrease in cell proliferation in several human tumor cell lines after irradiation with UVA light (GI50=15.2–0.2 μM). Their phototoxicity effected apoptosis in Jurkat cells with the involvement of mitochondria (as determined by the loss of mitochondrial membrane potential and production of reactive oxygen species) and lysosomes. The phototoxicity of these compounds could be explained by lipid peroxidation.
Low temperature pulsed electron deposition and characterization of ZnS films for application in solar cells
Authors: Zanettini S. , Bissoli F. , Nasi L. , Ranzieri P. , Gilioli E.
Published: May 2011

Zinc Sulphide films were grown by pulsed electron deposition (PED) from room temperature to 350 °C to investigate the possibility of its application in solar cells, in particular as an alternative buffer layer deposited at low temperature. The films were characterized by X‐ray diffraction, TEM, AFM, optical absorption and electrical measurements. ZnS films display crystalline structure and columnar growth at room temperature on amorphous substrate; the crystallization improves with the substrate temperature and is predominantly related to the cubic (111) orientation, while the thicker films show coexistence of hexagonal and cubic structures. All the samples have transparencies exceeding 70% in the range 400‐1000 nm, energy band gap between 3.25 and 3.65 eV increasing with temperature and resistivity in the range of 104‐106 Ωcm. The optimization of the growth rate as a function of the growth parameters (substrate temperature and electron gun voltage) is also discussed. The reported results indicate that ZnS might be a suitable material for photovoltaic applications, specifically in process requiring low deposition temperature. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tracing of islet graft survival by way of in vivo fluorescence imaging
Authors: Kahraman Sevim , Dirice Ercument , Hapil Fatma Z. , Ertosun Mustafa G. , Ozturk Saffet , Griffith Thomas S. , Sanlioglu Salih , Sanlioglu Ahter D.
Published: May 2011

Background

To increase the success rate in xenogeneic islet transplantation, proper assessment of graft mass is required following transplantation. For this reason, we aimed to develop a suitable fluorescence imaging system to monitor islet xenograft survival in diabetic mice.

Methods

Adenovirus vector encoding enhanced green fluorescent protein‐transduced rat pancreatic islets were transplanted under the renal capsule of streptozotocin‐induced diabetic mice and the fluorescence signal was quantified over time using a cooled charge‐coupled device. Non‐fasting blood glucose levels were recorded during the same period. Insulin release from transduced and control islets was detected via enzyme‐linked immunosorbent assay.

Results

Adenovirus vector encoding enhanced green fluorescent protein infection did not alter the function or survival of pancreatic islets post transduction. A direct correlation was found between the number of islets (250–750) transplanted under the kidney capsule and the blood glucose recovery.

Conclusions

Fluorescence imaging appears to be a useful tool for quantitative assessment of islet cell viability post transplantation and could permit earlier detection of graft rejection. Copyright © 2011 John Wiley & Sons, Ltd.
Benefits of a simple glycaemic protocol in an orthopaedic surgery ward: a randomized prospective study
Authors: Schroeder Josh E. , Liebergall M. , Raz I. , Egleston R. , Ben Sussan G. , Peyser A. , Eldor R.
Published: May 2011

Background

Hyperglycaemia and diabetes mellitus are common in patients hospitalized in the orthopaedic surgery ward. However, glycaemic control obtained during hospitalization is often suboptimal. No method for achieving adequate glycaemic control in this population has been validated in an in‐hospital setting.

Intervention

An intervention including an intensive subcutaneous insulin protocol in the orthopaedic department.

Methods

All diabetic patients admitted to the Department of Orthopaedic Surgery were prospectively randomized during a 6‐month period. One group (n = 30) received standard care with sliding scale insulin and the other group (n = 35) received the intervention protocol. During the intervention period, the staff was briefed on the importance of glucose monitoring and control. An intensive multiple‐injection protocol consisting of four daily regular/neutral protamine hagedorn (NPH) insulin injections was initiated in diabetic patients. The programme was followed up by a consulting diabetologist.

Results

Mean blood glucose levels throughout the hospitalization were 161.48 ± 3.8 mg/dL in the intervention group versus 175.29 ± 2.3 mg/dL in the control group (p < 0.0005). Hospitalization was shorter by 2 days in the intervention group (p < 0.05). The number of severe hyperglycaemic events (blood glucose level above 400 mg%) was significantly lower (p < 0.05) in the intervention group. There was no significant difference in the number of hypoglycaemic events.

Conclusions

The suggested four‐step intervention regimen improved glycaemic control of hospitalized patients in the orthopaedic department and simplified the ‘in‐house’ treatment of the diabetic patient. Hospital stays were reduced on average by two days (p < 0.05). Copyright © 2011 John Wiley & Sons, Ltd.
Prevalence, risk factors and complications associated with type 2 diabetes in migrant South Asians
Authors: Garduño‐Diaz Sara D. , Khokhar Santosh
Published: May 2011

It is estimated that type 2 diabetes (T2D) currently affects about 246 million people worldwide, with South Asians, especially Indians, having both the largest number of cases and the fastest growing prevalence. South Asian ethnicity has been identified as a major risk factor for the development of T2D with central adiposity, insulin resistance and an unfavourable lipid profile being identified as predominant signals of alarm. Leading databases, including Web of Science, Medline, PubMed and Science Direct, were consulted and manual searches were conducted for cited references in leading diabetes‐related journals. In all, 152 articles were included for the final assessment reported in this review. Genetic predisposition, central adiposity and unfavourable lifestyle, including physical inactivity and an unhealthy diet, were associated with the prevalence of T2D in migrant South Asians. ‘Westernization’, acculturation, socio‐economic factors and lack of knowledge about the disease have also been identified as contributors to the development of T2D in this population. Higher prevalence of T2D in migrant South Asians may not be entirely attributed to genetic predisposition; hence, ethnicity and associated modifiable risk factors need further investigation. Preventive measures and appropriate interventions are currently limited by the lack of ethnic‐specific cut‐off points for anthropometric and biological markers, as well as by the absence of reliable methods for dietary and physical activity assessment. This article describes the prevalence rate, risk factors and complications associated with T2D in migrant South Asians living in different countries. Copyright © 2011 John Wiley & Sons, Ltd.
NKG2D performs two functions in invariant NKT cells: Direct TCR‐independent activation of NK‐like cytolysis and co‐stimulation of activation by CD1d
Authors: Kuylenstierna Carlotta , Björkström Niklas K. , Andersson Sofia K. , Sahlström Peter , Bosnjak Lidija , Paquin‐Proulx Dominic , Malmberg Karl‐Johan , Ljunggren Hans‐Gustaf , Moll Markus , Sandberg Johan K.
Published: May 2011

Invariant NKT cells are important in the activation and regulation of immune responses. They can also function as CD1d‐restricted killer cells. However, the role of activating innate NK‐cell receptors expressed on NKT cells in triggering cytolytic function is poorly characterized. Here, we initially confirmed that the cellular stress‐ligand receptor NKG2D is expressed on CD4− NKT cells, whereas most CD4+ NKT cells lack this receptor. Interestingly, NKG2D+ NKT cells frequently expressed perforin, and both NKG2D and perforin localized at the site of contact with NKG2D ligand‐expressing target cells. CD4− NKT cells degranulated in response to NKG2D engagement in a redirected activation assay independent of stimulation via their invariant TCR. NKT cells killed P815 cells coated with anti‐NKG2D mAb and CD1d‐negative K562 tumor target cells in an NKG2D‐dependent manner. Furthermore, NKG2D engagement co‐stimulated TCR‐mediated NKT‐cell activation in response to endogenous CD1d‐presented ligands or suboptimal levels of anti‐CD3 triggering. These data indicate that the CD4− subset of human NKT cells can mediate direct lysis of target cells via NKG2D engagement independent of CD1d, and that NKG2D also functions as a co‐stimulatory receptor in these cells. NKG2D thus plays both a direct and a co‐stimulatory role in the activation of NKT cells.
Selection of T‐cell receptors with a recurrent CDR3β peptide‐contact motif within the repertoire of alloreactive CD8+ T cells
Authors: Scifo Caroline , Mekaelian Laura , Munyazesa Elisaphane , Schmitt‐Verhulst Anne‐Marie , Guimezanes Annick
Published: May 2011

Peptide/MHC complexes recognized by alloreactive T lymphocytes (TLs) have been identified, but their contribution to in vivo allo‐rejection is not known. We previously characterized the peptide pBM1, highly represented among endogenous H‐2Kb (Kb)‐associated peptides and critically required to induce full activation of H‐2k monoclonal CD8+ TLs expressing the cognate TCR‐BM3.3. Here, we asked whether a pBM1/Kb‐specific TL subset could be detected within a polyclonal TL population rejecting allogeneic cells in vivo. We show that the proportion of pBM1/Kb‐binding CD8+ TLs increased from <0.04% in naïve mice to 3% of activated CD44+ CD8+ TLs in H‐2k mice rejecting Kb‐expressing cells. Among these, TCR‐Vβ2 usage was greatly enriched, and 75% of them shared a TCR‐Vβ2 CDR3β motif with the prototype TCR‐BM3.3. Fewer than 5% of Kb‐reactive CD44+ CD8+ TLs not binding pBM1/Kb displayed this CDR3β motif. We found that the recurrent CDR3β motif of pBM1/Kb‐binding TLs was assembled from distinct V/D/J recombination events, suggesting that it is recruited upon immunization for its optimal TCR‐peptide/MHC fit. Thus, a CDR3β motif generated by a process akin to “convergent recombination” accounts for a sizable fraction of the alloreactive anti‐Kb TCR repertoire.
Expeditious Construction of Spiro‐Pyrrolidines by an Autocatalytic One‐Pot, Five‐Component, 1,3‐Dipolar Cycloaddition of in situ Generated Azomethine Ylides and Olefinic Dipolarophiles
Authors: Li Ming , Gong Fu‐Meng , Wen Li‐Rong , Li Zhao‐Rui
Published: May 2011

Two series of previously unknown spiro‐pyrrolidine derivatives were prepared by a five‐component reaction that employed ninhydrin, 1,2‐phenylenediamine, sarcosine, aldehydes, and malononitrile or cyanoacetic ester in a solvothermal synthesis. This is the first report of an autocatalytic five‐component reaction involving a classical Huisgen reaction, in which the dipole – an azomethine ylide – and the dipolarophile were simultaneously generated in situ. The 1,3‐dipolar cycloaddition reaction was found to proceed in a highly regio‐ and diastereoselective manner. The methodology for the preparation of the spiro‐pyrrolidines could be an ideal tool for green chemistry and the synthesis of alkaloids.
A Tandem Isomerization–Mannich Reaction for the Enantioselective Synthesis of β‐Amino Ketones and β‐Amino Alcohols with Applications as Key Intermediates for ent‐Nikkomycins and ent‐Funebrine
Authors: Cao Hai Thuong , Roisnel Thierry , Valleix Alain , Grée René
Published: May 2011

β‐Amino ketones, with a primary amino group, are easily obtained in good yields and excellent enantioselectivities through a short sequence that involves, as a key step, a tandem isomerization–Mannich reaction from allylic alcohols with N‐tert‐butanesulfinimines. This method was used for the enantioselective synthesis of corresponding β‐amino alcohols and also for key intermediates in the preparation of ent‐nikkomycins or ent‐funebrine.
A Practical, One‐Pot Multicomponent Synthesis of α‐Amidosulfides and Their Application as Latent N‐Acylimines in the Friedel–Crafts Reaction
Authors: George Nicolas , Bekkaye Mathieu , Masson Géraldine , Zhu Jieping
Published: May 2011

A novel one‐pot, three‐component synthesis of N‐acyl or N‐carbamoyl‐α‐amidosulfides 4 is described. The three‐component reaction of aldehydes 1, primary carbamates (or amides) 2 and phenylsulfinic acid (6a) afforded α‐amidosulfones 7, which after addition of sodium thiolate were in situ transformed into stable α‐amidosulfides 4 in good to excellent yields. We demonstrated that silver salts or Brønsted acids were able to promote the formation of aliphatic and aromatic N‐acylimines from 4 in quantitative yield under mild conditions. The phosphoric acid catalyzed Friedel–Crafts alkylation of 3‐substituted indoles with α‐amidosulfides 4 leading to 2,3‐disubstitued indoles was also documented.
Fabrication of Au‐Nanoparticle/TiO2‐Nanotubes Electrodes Using Electrochemical Methods and Their Application for Electrocatalytic Oxidation of Hydroquinone
Authors: Hosseini Mir Ghasem , Momeni Mohamad Mohsen , Faraji Masoud
Published: May 2011

Gold nanoparticle (Au‐NPs)‐Titanium oxide nanotube (TiO2‐NTs) electrodes are prepared by using galvanic deposition of gold nanoparticles on TiO2‐NTs electrodes as support. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy results indicate that nanotubular TiO2 layers consist of individual tubes of about 60–90 nm diameters and gold nanoparticles are well‐dispersed on the surface of TiO2‐NTs support. The electrooxidation of hydroquinone of Au‐NPs/TiO2‐NTs electrodes is investigated by different electrochemical methods. Au‐NPs/TiO2‐NTs electrode can be used repeatedly and exhibits stable electrocatalytic activity for the hydroquinone oxidation. Also, determination of hydroquinone in skin cream using this electrode was evaluated. Results were found to be satisfactory and no matrix effects are observed during the determination of hydroquinone content of the “skin cream” samples.
A Combination Bismuth Bulk Electrode and Its Use in Adsorptive Constant‐Current Stripping Chronopotentiometry for Iron Using Solochrome Violet RS
Authors: Pimrote Wachirawan , Ratana‐Ohpas Roongroje , Renman Lars
Published: May 2011

A new combination bismuth bulk electrode allowing potentiostatic control to be maintained in a suspended sample drop is described. The electrode was tested by adsorptive constant‐current stripping chronopotentiometry for iron(III) using Solochrome Violet RS. Optimum conditions were similar to those established with mercury‐based electrodes. With an electropolishing scheme, a reproducibility better than 2 % (n=54) was attainable. The limit of detection was 0.6 µg L−1 in deoxygenated samples. A partial least squares calibration gave a result of 972±78 µg L−1 (95 %, n=5) for a 1000±5 µg L−1 iron reference solution.
Extension of the Adaptive Huber Method for Solving Integral Equations Occurring in Electroanalysis, onto Kernel Function Representing Fractional Diffusion
Authors: Bieniasz Lesław K.
Published: May 2011

Electroanalytical transient experiments performed under conditions of anomalous diffusion have recently attracted some attention. In order to enable automatic simulation of such experiments in the framework of the formalism of integral equations, the adaptive Huber method, recently elaborated by the present author, is extended onto integral transformation kernel function K(t,τ)=(t−τ)α/2−1 (where 0<α≤1), representing fractional diffusion. The extended method is tested on a model integral equation describing cyclic voltammetry for a reversible charge transfer reaction. The performance of the method is found similar to the case of ordinary diffusion.
Graphite Electrode Coated with a 7,16‐Dibenzyl‐1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecane‐Multiwalled Carbon Nanotube Composite as Sensor For Detection of Samarium
Authors: Agrahari Sunil K. , Srivastava Ashwini K.
Published: May 2011

A composite multiwalled carbon nanotube polyvinyl chloride electrode based on 7,16‐dibenzyl‐1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecane (DBDA18C6) as Sm3+ ionophore is reported. This potentiometric sensor showed a wide linear working range, 1×10−2–1×10−8 M, Nernstian slope, 20.2±0.48 mV per decade and a limit of detection, 6.3±0.36×10−9 M. It works in the pH range 2.5–8.5 and shows a good selectivity over a number of metal ions. It has been found suitable for the analysis of ores and industrial effluents. The electrode surface is characterized by FRA and AFM.
Nanobioelectroanalysis Based on Carbon/Inorganic Hybrid Nanoarchitectures
Authors: Campuzano Susana , Wang Joseph
Published: May 2011

The emergence of nanotechnology has opened new horizons for electrochemical biosensors. This review highlights new concepts for electrochemical biosensors based on different carbon/inorganic hybrid nanoarchitectures. Particular attention will be given to hybrid nanostructures involving 1‐ or 2‐dimensional carbon nanotubes or graphene along with inorganic nanoparticles (gold, platinum, quantum dot (QD), metal oxide). Latest advances (from 2007 onwards) in electrochemical biosensors based on such hybrids of carbon/inorganic‐nanomaterial heterostructures are discussed and illustrated in connection to enzyme electrodes for blood glucose or immunoassays of cancer markers. Several strategies for using carbon/inorganic nanohybrids in such bioaffinity and biocatalytic sensing are described, including the use of hybrid nanostructures for tagging or modifying electrode transducers, use of inorganic nanomaterials as surface modifiers along with carbon nanomaterial label carriers, and carbon nanostructure‐based electrode transducers along with inorganic amplification tags. The implications of these nanoscale bioconjugated hybrid materials on the development of modern electrochemical biosensors are discussed along with future prospects and challenges.
Psychosocial consequences of disordered eating attitudes in elite female figure skaters
Authors: Scoffier Stéphanie , Woodman Tim , d'Arripe‐Longueville Fabienne
Published: May 2011

The purpose of this study was to test a model of the effects of athletes' eating disorders on coach, sport friend and parent social relationships and peer social acceptance through physical self‐perceptions (i.e. perceived physical appearance and perceived physical ability). The sample comprised 199 elite female figure skaters. The data were analysed using structural equation modelling. Our results showed that the effects of athletes' eating disorders on social relationships were not mediated by physical self‐perceptions. Athletes' eating disorders directly negatively influenced the quality of the parent–athlete relationship, thus confirming previous findings in young adults. Contrary to the literature, eating disorders were positively related to perceived physical ability. This paradoxical finding is discussed in relation to achievement theories and the particularity of the sport context. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association
Disordered eating and exercise: Development and preliminary validation of the compulsive exercise test (CET)
Authors: Taranis Lorin , Touyz Stephen , Meyer Caroline
Published: May 2011

Objective

The Compulsive Exercise Test (CET) was developed to assess the primary factors operating in the maintenance of excessive exercise.

Methods

A total of 367 young female exercisers were recruited from University campuses. Across three separate studies, the participants completed either the CET alone, or the CET and other standard self‐report measures of excessive exercise and eating psychopathology.

Results

Factor analyses yielded five factors from which a final 24‐item, five subscale measure was constructed. The CET demonstrated high internal consistency across the three samples. Supporting the concurrent and convergent validity of the scale, the CET correlated in the expected direction with existing measures of excessive exercise and eating pathology. As expected, the CET explained greater variance in eating pathology than existing measures of excessive exercise.

Discussion

The resulting subscales of the CET are consistent with a cognitive‐behavioural maintenance model of excessive exercise and support the multidimensionality of the excessive exercise construct. Further research is required to validate the instrument within a sample of eating disordered women. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association.
Exercise dependence score in patients with longstanding eating disorders and controls: The importance of affect regulation and physical activity intensity
Authors: Bratland‐Sanda Solfrid , Martinsen Egil W. , Rosenvinge Jan H. , Rø Øyvind , Hoffart Asle , Sundgot‐Borgen Jorunn
Published: May 2011

Objective

To examine associations among exercise dependence score, amount of physical activity and eating disorder (ED) symptoms in patients with longstanding ED and non‐clinical controls.

Methods

Adult female inpatients (n = 59) and 53 age‐matched controls participated in this cross sectional study. Assessments included the eating disorders examination, eating disorders inventory, exercise dependence scale, reasons for exercise inventory, and MTI Actigraph accelerometer.

Results

Positive associations were found among vigorous, not moderate, physical activity, exercise dependence score and ED symptoms in patients. In the controls, ED symptoms were negatively associated with vigorous physical activity and not correlated with exercise dependence score. Exercise for negative affect regulation, not weight/appearance, and amount of vigorous physical activity were explanatory variables for exercise dependence score in both groups.

Conclusions

The positive associations among exercise dependence score, vigorous physical activity and ED symptoms need proper attention in the treatment of longstanding ED. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association.
Impact of the magnitude and frequency of debris‐flow events on the evolution of an alpine alluvial fan during the last two centuries: responses to natural and anthropogenic controls
Authors: Colombera Luca , Bersezio Riccardo
Published: May 2011

The dynamics and the surface evolution of a post‐LGM debris‐flow‐dominated alluvial fan (Tartano alluvial fan), which lies on the floor of an alpine valley (Valtellina, Northern Italy), have been investigated by means of an integrated study comprising geomorphological field work, a sedimentological study, photointerpretation, quantitative geomorphology, analysis of ancient to modern cartography and consultation of historical documents and records. The fan catchment meteoclimatic, geological and geomorphological characteristics result in fast rates of geomorphic reorganization of the fan surface (2 km2). The dynamics of the fan are determined by the alternation of low‐return period catastrophic alluvial events dominated by non‐cohesive debris flows triggered by extreme rainstorms which caused aggradation and steepening of the fan and avulsion of its main channel, with periods of low to moderate streamflow discharge punctuated by low‐ to intermediate‐magnitude flood events, causing slower but steady topographic reworking. The most ancient parts of the fan surface date back at least to the first half of the 19th century, but most of the fan surface has been restructured after 1911, mainly during the debris‐flow‐dominated events of 1911 and 1987. Phases of rapid fan toe incision and fan degradation have been recognized; since the 1930s or 1940s, the Tartano fan has been subjected to a state of deep entrenchment and narrowing of the main trunk channel and distributary area. Post‐Little Ice Age climate change and present‐day surface uplift rates have been considered as possible explanations for the observed geomorphic evolution, but tectonic or climatic controls cannot account for the order of magnitude of the erosional pace. Anthropogenic controls plausibly override the natural ones: in particular, the building of a dam in the late 1920s, about 2 km upstream of the fan, seems to have triggered fan dissection, having altered the sediment discharge through sediment retention. Copyright © 2011 John Wiley & Sons, Ltd.
Acute and chronic toxicity of boron to a variety of freshwater organisms
Authors: Soucek David J , Dickinson Amy , Koch Brian T
Published: May 2011

Boron enters the aquatic environment from various sources, including weathering of borates, sewage effluents, coal combustion, use of cleaning compounds, and agrochemicals. The present study was designed to generate data on acute and chronic boron toxicity in support of an update of water quality standards in Illinois, USA. We examined the acute toxicity of boron to eight different freshwater organisms including a fish, an insect, two crustaceans, and four bivalve mollusks. To our knowledge, this is the first study to present data on the toxicity of boron to freshwater mollusks. We also sought to clarify whether hardness or pH affect boron toxicity to aquatic life, and to quantify chronic effect levels in two freshwater species. Sensitivity among the various species ranged widely, with the fathead minnow (Pimephales promelas) being the most sensitive. Neither pH nor hardness had a consistent effect on acute boron toxicity to two crustaceans (Ceriodaphnia dubia and Hyalella azteca), but we observed evidence that chloride reduces boron toxicity to H. azteca. The fathead minnow, while more acutely sensitive than the other species, had a lower acute to chronic ratio than did H. azteca, which had reduced reproduction at 13 mg/L. While we do not know the extent to which the eight tested species represent the range of sensitivities of native but untested species in Illinois, the current water quality standard for Illinois (1 mg/L) is conservative with regard to the native species tested thus far. Environ. Toxicol. Chem. 2011; 30:1906–1914. © 2011 SETAC
Application of chemical toxicity distributions to ecotoxicology data requirements under REACH
Authors: Williams E. Spencer , Berninger Jason P , Brooks Bryan W
Published: May 2011

The European Union's REACH regulation has further highlighted the lack of ecotoxicological data for substances in the marketplace. The mandates under REACH (registration, evaluation, authorization, and restriction of chemicals) to produce data and minimize testing on vertebrates present an impetus for advanced hazard assessment techniques using read-across. Research in our group has recently focused on probabilistic ecotoxicological hazard assessment approaches using chemical toxicity distributions (CTDs). Using available data for chemicals with similar modes of action or within a chemical class may allow for selection of a screening point value (SPV) for development of environmental safety values, based on a probabilistic distribution of toxicity values for a specific endpoint in an ecological receptor. Ecotoxicity data for acetylcholinesterase inhibitors and surfactants in Daphnia magna and Pimephales promelas were gathered from several data sources, including the U.S. Environmental Protection Agency's ECOTOX and Pesticides Ecotoxicity databases, the peer-reviewed literature, and the Human and Environmental Risk Assessment (HERA) project. Chemical toxicity distributions were subsequently developed, and the first and fifth centiles were used as SPVs for the development of screening-predicted no-effect concentrations (sPNECs). The first and fifth centiles of these distributions were divided by an assessment factor of 1,000, as recommended by REACH guidance. Use of screening values created using these techniques could support the processes of data dossier development and environmental exposure assessment, allowing for rigorous prioritization in testing and monitoring to fill data gaps. Environ. Toxicol. Chem. 2011; 30:1943–1954. © 2011 SETAC
Locally Resolved Measurements in a Segmented HTPEM Fuel Cell with Straight Flow‐Fields
Authors: Siegel C. , Bandlamudi G. , Filusch F. , Heinzel A.
Published: May 2011

Significant advances have been reported in building and testing of high‐temperature polymer electrolyte membrane (HTPEM) fuel cells and stacks during recent years. Quantity distribution measurement techniques (e.g. current density, temperature and electrochemical impedance spectroscopy (EIS)) using segmented cells are commonly used to characterise low‐temperature PEM (LTPEM) fuel cells. Performing these measurements at higher temperatures is more difficult and a relatively new process. For this study, a fully operational segmented HTPEM fuel cell using a straight flow‐field configuration was designed, constructed and tested. The cathode side bipolar half‐plate consisted of 36 exchangeable segments, whereas, the anode side bipolar half‐plate was not segmented. The cell was operated at various operating temperatures with various anode gas compositions and air (no backpressure). In addition to the experimental results, a simple computational fluid dynamics model based on COMSOL Multiphysics® 3.5a was used to support the observed behaviour during segmented measurements. The computational domain consisted of the cathode side gas channels and the porous media. All of the boundary conditions and gas properties were defined in a manner similar to the experimental investigations. Some of the theoretical results were compared to the experimental results and conclusions were drawn.
Graphitic Carbon as Durable Cathode‐Catalyst Support for PEFCs
Authors: Vinod Selvaganesh S. , Selvarani G. , Sridhar P. , Pitchumani S. , Shukla A. K.
Published: May 2011

Long‐term deterioration in the performance of PEFCs is attributed largely to reduction in active area of the platinum catalyst at cathode, usually caused by carbon‐support corrosion. It is found that the use of graphitic carbon as cathode‐catalyst support enhances its long‐term stability in relation to non‐graphitic carbon. This is because graphitic‐carbon‐supported‐Pt (Pt/GrC) cathodes exhibit higher resistance to carbon corrosion in‐relation to non‐graphitic‐carbon‐supported‐Pt (Pt/Non‐GrC) cathodes in PEFCs during accelerated stress test (AST) as evidenced by chronoamperometry and carbon dioxide studies. The corresponding change in electrochemical surface area (ESA), cell performance and charge‐transfer resistance are monitored through cyclic voltammetry (CV), cell polarisation and impedance measurements, respectively. The degradation in performance of PEFC with Pt/GrC cathode is found to be around 10% after 70 h of AST as against 77% for Pt/Non‐GrC cathode. It is noteworthy that Pt/GrC cathodes can withstand even up to 100 h of AST with nominal effect on their performance. X‐ray diffraction (XRD), Raman spectroscopy, transmission electron microscopy and cross‐sectional field‐emission scanning electron microscopy (FE‐SEM) studies before and after AST suggest lesser deformation in catalyst layer and catalyst particles for Pt/GrC cathodes in relation to Pt/Non‐GrC cathodes, reflecting that graphitic carbon‐support resists carbon corrosion and helps mitigating aggregation of Pt‐particles.
Combined Usage of Sodium Borohydride and Aluminum Powder for High‐performance Hydrogen Generation
Authors: Dai H.‐B. , Ma G.‐L. , Xia H.‐J. , Wang P.
Published: May 2011

The sodium borohydride (NaBH4)‐based hydrolysis system has received considerable interest as a potential hydrogen source for vehicular application. But its practical application was greatly restricted by the low hydrogen density and high material cost. In the present study, we reported that addition of aluminum (Al) powder is an easy but highly effective way for addressing the problems of the NaBH4‐based hydrolysis system. The system was composed of alkaline aqueous solution of NaBH4 and solid powder mixture of Al and Co2B catalyst. The effects of alkaline concentration, NaBH4 concentration and Al amount on the hydrogen generation (HG) performance of the system were investigated. Our study showed that there exist a mutual‐promoting mechanism between the hydrolysis reaction of NaBH4 and the Al/H2O reaction. As a consequence, this system exhibited distinct advantages over the conventional NaBH4‐based system in terms of HG rate, fuel conversion, hydrogen density and H2 production cost. These favourable attributes make the (NaBH4+Al)/H2O system attractive for mobile/portable hydrogen source applications.
Estimating the designated use attainment decision error rates of US Environmental Protection Agency's proposed numeric total phosphorus criteria for Florida, USA, colored lakes
Authors: McLaughlin Douglas B.
Published: May 2011

The utility of numeric nutrient criteria established for certain surface waters is likely to be affected by the uncertainty that exists in the presence of a causal link between nutrient stressor variables and designated use–related biological responses in those waters. This uncertainty can be difficult to characterize, interpret, and communicate to a broad audience of environmental stakeholders. The US Environmental Protection Agency (USEPA) has developed a systematic planning process to support a variety of environmental decisions, but this process is not generally applied to the development of national or state-level numeric nutrient criteria. This article describes a method for implementing such an approach and uses it to evaluate the numeric total P criteria recently proposed by USEPA for colored lakes in Florida, USA. An empirical, log-linear relationship between geometric mean concentrations of total P (a potential stressor variable) and chlorophyll a (a nutrient-related response variable) in these lakes—that is assumed to be causal in nature—forms the basis for the analysis. The use of the geometric mean total P concentration of a lake to correctly indicate designated use status, defined in terms of a 20 µg/L geometric mean chlorophyll a threshold, is evaluated. Rates of decision errors analogous to the Type I and Type II error rates familiar in hypothesis testing, and a 3rd error rate, Eni, referred to as the nutrient criterion–based impairment error rate, are estimated. The results show that USEPA's proposed “baseline” and “modified” nutrient criteria approach, in which data on both total P and chlorophyll a may be considered in establishing numeric nutrient criteria for a given lake within a specified range, provides a means for balancing and minimizing designated use attainment decision errors. Integr Environ Assess Manag 2012;8:167–174. © 2011 SETAC