bluuebunny/crossref_metadata_2025 huggingface dataset:
Polymer Nanoparticle Hydrogels with Autonomous Affinity Switching for the Protection of Proteins from Thermal Stress
Authors: Beierle John M. , Yoshimatsu Keiichi , Chou Beverly , Mathews Michael A. A. , Lesel Benjamin K. , Shea Kenneth J.
Published: July 2014

We report a new material design concept for synthetic, thermally responsive poly(N‐isopropylacrylamide)‐based copolymer nanoparticle (NP) hydrogels, which protect proteins from thermal stress. The NP hydrogels bind and protect a target enzyme from irreversible activity loss upon exposure to heat but “autonomously” release the enzyme upon subsequent cooling of the solution. Incorporation of the optimized amount of negatively charged and hydrophobic comonomers to the NP hydrogels was key to achieve these desired functions. As the NP hydrogels do not show a strong affinity for the enzyme at room temperature, they can remain in solution without adversely affecting enzymatic activity or they can be removed by filtration to leave the enzyme in solution. The results demonstrate the promise of this approach for improving the thermal tolerance of proteins.
Light‐Driven Organocatalysis Using Inexpensive, Nontoxic Bi2O3 as the Photocatalyst
Authors: Riente Paola , Matas Adams Alba , Albero Josep , Palomares Emilio , Pericàs Miquel A.
Published: July 2014

The development of enantioselective catalytic processes that make use of sunlight as the energy source and nontoxic, affordable materials as catalysts represents one of the new and rapidly evolving areas in chemical research. The direct asymmetric α‐alkylation of aldehydes with α‐bromocarbonyl compounds can be successfully achieved by combining bismuth‐based materials as low‐band‐gap photocatalysts with the second‐generation MacMillan imidazolidinone as the chiral catalyst and simulated sunlight as a low‐cost and clean energy source. This reaction also proceeded with high efficiency when the reaction vial was exposed to the morning sunlight on a clear September day in Tarragona, Spain.
Efficient hydroxylation of aromatic compounds catalyzed by an iron(II) complex with H2O2
Authors: Wang Xiao , Zhang Tianyong , Li Bin , Yang Qiusheng , Jiang Shuang
Published: July 2014

A mononuclear iron(II) complex, Et4N[Fe(C10H6NO2)3], coordinated by three 1‐nitroso‐2‐naphtholate ligands in a fac‐N3O3 geometry, was initiated to catalyze the direct hydroxylation of aromatic compounds to phenols in the presence of H2O2 under mild conditions. Various reaction parameters, including the catalyst dosage, temperature, mole ratio of H2O2 to benzene, reaction time and solvents which could affect the hydroxylation activity of the catalyst, were investigated systematically for benzene hydroxylation to obtain ideal benzene conversion and high phenol distribution. Under the optimum conditions, the benzene conversion was 10.2% and only phenol was detected. The catalyst was also found to be active towards hydroxylation of other aromatic compounds with high substrate conversions. The hydroxyl radical formed due to the reaction of the catalyst and H2O2 was determined to be the crucial active intermediate in the hydroxylation. A rational pathway for the formation of the hydroxyl radical was proposed and justified by the density functional theory calculations. Copyright © 2014 John Wiley & Sons, Ltd.
Numerical simulation of the effects of vaporization on the motion of PIG during pigging process
Authors: Deng Tao , Gong Jing , Zhou Jun , Zhang Yu , Li Haocheng
Published: July 2014

During the course of pigging after water pressure test, when pressure drops to vapor pressure, localized vaporization always occurs at pipeline terminations or at physical high points in the pipeline. PIG is most effective when it runs at a near constant speed. The appearance of a vapor region may dramatically affect the PIG motion and ultimately contribute to impulse pressures at the end of pigging process. Large pressures may cause the PIG to run at extremely high speed, which is a highly dangerous situation. Further, the pigging efficiency can be compromised. The proposed model for estimating the pig dynamics takes into account vaporization. The basic equations governing the conservation of mass and momentum for the gas and liquid fluids were solved together with the momentum equations for the pig by applying the method of characteristics. Moreover, the new pigging model takes advantage of discrete‐vapor‐cavity model to predict the vaporization and location of vapor region. Numerical simulation results for gas–liquid pipeline pigging process are in good agreement with field data to validate the model developed. The model also contains the capability of PIG tracking and the prediction of impulse pressures, which can help the operator to control the PIG speed before it reaches the end of the pipeline. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Preparation of asymmetric membranes and their applications in the restoration of groundwater contaminated by trichloroethylene via two‐step bioremediation technology
Authors: Song Zhenyu , Yang Wei , Zhang Jinghui , Bi Tao , Li Ye , Yuan Shanshan
Published: July 2014

Asymmetric hollow‐fiber membranes were fabricated via a thermally induced phase‐separation process, and the properties of the membrane were investigated. A bubbleless‐aeration membrane module (BAMM) was designed for the purpose of releasing hydrogen or oxygen. Then, the anaerobic reductive dechlorination (ARD) remediation zone and the aerobic oxidative decomposition (AOD) remediation zone were founded based on the BAMM. The effects of the aeration pressure of hydrogen and oxygen on the oxidation reduction potential (ORP) of the liquid phase were investigated. The groundwater contaminated by trichloroethylene (TCE) was used as the restoring object. The effect of the hydrogen aeration on the ARD process and the effect of the oxygen aeration on the AOD process were also investigated. The results show that the ORP–retention time curve in the ARD zone presented an upward opening parabola of growth, whereas the ORP–retention time curve in the AOD zone presented a downward opening parabola of growth. It took 8 days for TCE to decrease from 500 to 52 μg/L in the ARD zone, whereas it took 24 h for cis‐dichloroethylene to decrease from 52 to 35 μg/L in the AOD zone. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41176.
PARASITIZATION BY SCLERODERMA GUANI INFLUENCES EXPRESSION OF SUPEROXIDE DISMUTASE GENES IN TENEBRIO MOLITOR
Authors: Zhu Jia‐Ying , Ze Sang‐Zi , Stanley David W. , Yang Bin
Published: July 2014

Superoxide dismutase (SOD) is an antioxidant enzyme involved in detoxifying reactive oxygen species. In this study, we identified genes encoding the extracellular and intracellular copper‐zinc SODs (ecCuZnSOD and icCuZnSOD) and a manganese SOD (MnSOD) in the yellow mealworm beetle, Tenebrio molitor. The cDNAs for ecCuZnSOD, icCuZnSOD, and MnSOD, respectively, encode 24.55, 15.81, and 23.14 kDa polypeptides, which possess structural features typical of other insect SODs. They showed 20–94% identity to other known SOD sequences from Bombyx mori, Musca domestica, Nasonia vitripennis, Pediculus humanus corporis, and Tribolium castaneum. Expression of these genes was analyzed in selected tissues and developmental stages, and following exposure to Escherichia coli and parasitization by Scleroderma guani. We recorded expression of all three SODs in cuticle, fat body, and hemocytes and in the major developmental stages. Relatively higher expressions were detected in late‐instar larvae and pupae, compared to other developmental stages. Transcriptional levels were upregulated following bacterial infection. Analysis of pupae parasitized by S. guani revealed that expression of  T. molitor SOD genes was significantly induced following parasitization. We infer that these genes act in immune response and in host–parasitoid interactions.
Overexpression of artemisinic aldehyde Δ11 (13) reductase gene–enhanced artemisinin and its relative metabolite biosynthesis in transgenic Artemisia annua L.
Authors: Yuan Yuan , Liu Wanhong , Zhang Qiaozhuo , Xiang Lien , Liu Xiaoqiang , Chen Min , Lin Zhi , Wang Qiang , Liao Zhihua
Published: July 2014

Artemisinic aldehyde Δ11 (13) reductase (DBR2) is the checkpoint enzyme catalyzing artemisinic aldehyde to form dihydroartemisinic aldehyde directly involved in artemisinin biosynthetic pathway. In the present study, DBR2 was employed to engineer the biosynthetic pathway of artemisinin in transgenic plants of Artemisia annua L. Seven independent transgenic plants of A. annua with DBR2 overexpression driven by the cauliflower mosaic virus 35S promoter were obtained by Agrobacterium‐mediated genetic transformation and confirmed by genomic PCR. The results of real‐time qPCR analysis showed that the expression levels of DBR2 gene in all the seven transgenic lines were significantly higher than in nontransgenic control. The high‐performance liquid chromatography analysis of artemisinin and its relative metabolites demonstrated that the contents of artemisinin and its direct precursor dihydroartemisinic acid were remarkably increased in the transgenic plants of A. annua with DBR2 overexpression. Interestingly, it was also found that the contents of arteannuin B and its direct precursor artemisinic acid in the branch pathway competing against artemisinin biosynthesis were also improved in DBR2‐overexpressed A. annua plants. The transgenic results in the present study indicated that DBR2 is a useful structural gene in engineering the artemisinin biosynthetic pathway to develop genetically modified A. annua with the higher yield of artemisinin.
Capillary electrophoresis coupled with electrochemiluminescence for determination of atomoxetine hydrochloride and the study on its interactions with three proteins
Authors: Zeng Hua‐jin , Yang Ran , Zhang Ying , Li Jian‐jun , Qu Ling‐bo
Published: July 2014

A simple, rapid and sensitive method for the determination of atomoxetine hydrochloride (AH) by capillary electrophoresis with electrochemiluminescence detection (CE‐ECL) using tris(2,2′‐bipyridyl) ruthenium (II) was developed. Under optimized conditions, the determinations of AH in capsules and rat plasmas and the study on its interactions with three plasma proteins, including bovine serum albumin, cytochrome c and myoglobin were performed successfully. Relative to some previous studies, in this paper the methodologies for the determination of AH in aqueous solution and spiked plasma systems were established, respectively. By comparing the difference between the two work curves of two systems, the matrix effect in plasma samples on the determination of AH by the CE‐ECL method was discussed in detail. The results indicated that the effect of the matrix in plasma samples should not be ignored even if no obvious interference was found in the electropherograms and the establishment of method validation in complex samples by the CE‐ECL method was necessary. Copyright © 2014 John Wiley & Sons, Ltd.
Can proline‐rich polypeptide complex mimic the effect of nerve growth factor?
Authors: Zabłocka Agnieszka , Urbaniak Anna , Kuropatwa Marianna , Zyzak Joanna , Rossowska Joanna , Janusz Maria
Published: July 2014

Naturally occurring compounds that can act as prosurvival factors and neurite formation stimulants in the conditions of reduced neurotrophins production are important both in neuronal protection and therapy of neurodegenerative disorders. Therefore, the role of proline‐rich polypeptide complex (PRP) and its nonapeptide fragment (NP) in the promotion of pheochromocytoma cell line (PC12) survival and neurite outgrowth pathway is presented. It was shown that PRP/NP did not affect the neuronal nitric oxide synthase (nNOS) at the transcriptional and protein level. However, the activity of nNOS and intracellular nitric oxide (NO) concentration was markedly increased after treatment of PC12 cells with peptides. This reaction was inhibited byl‐NAME—nNOS inhibitor. It was shown that PRP and NP induce the soluble guanylyl cyclase to release higher amount of cyclic GMP (cGMP), and subsequently, the increased phosphorylation of extracellular signal‐regulated kinases 1 and 2 (ERK1/2) is observed. This effect was abolished by both U0126 (inhibitor of ERK1/2) and also byl‐NAME. Reduction of ERK1/2 activity observed in the presence of nNOS inhibitor suggests that its activation is NO‐dependent. The presented results shed some light on the mechanism of action of PRP complex. PRP and NP can activate NO/cGMP/ERK1/2 signaling pathway, similarly to nerve growth factor (NGF). The prosurvival action and short fibers formation suggest the role of PRP and NP in neuroprotection and the initiation of neuritogenesis. They can also participate in the amplification of signals controlling the survival and differentiation of neurons effect when the deficit of NGF takes place. © 2014 BioFactors, 40(5):501–512, 2014
Resolution and isolation of enantiomers of (±)‐isoxsuprine using thin silica gel layers impregnated with l‐glutamic acid, comparison of separation of its diastereomers prepared with chiral derivatizing reagents having l‐amino acids as chiral auxiliaries
Authors: Bhushan Ravi , Nagar Hariom
Published: July 2014

Thin silica gel layers impregnated with optically pure l‐glutamic acid were used for direct resolution of enantiomers of (±)‐isoxsuprine in their native form. Three chiral derivatizing reagents, based on DFDNB moiety, were synthesized having l‐alanine, l‐valine and S‐benzyl‐l‐cysteine as chiral auxiliaries. These were used to prepare diastereomers under microwave irradiation and conventional heating. The diastereomers were separated by reversed‐phase high‐performance liquid chromatography on a C18 column with detection at 340 nm using gradient elution with mobile phase containing aqueous trifluoroacetic acid and acetonitrile in different compositions and by thin‐layer chromatography (TLC) on reversed phase (RP) C18 plates. Diastereomers prepared with enantiomerically pure (+)‐isoxsuprine were used as standards for the determination of the elution order of diastereomers of (±)‐isoxsuprine. The elution order in the experimental study of RP‐TLC and RP‐HPLC supported the developed optimized structures of diastereomers based on density functional theory. The limit of detection was 0.1–0.09 µg/mL in TLC while it was in the range of 22–23 pg/mL in HPLC and 11–13 ng/mL in RP‐TLC for each enantiomer. The conditions of derivatization and chromatographic separation were optimized. The method was validated for accuracy, precision, limit of detection and limit of quantification. Copyright © 2014 John Wiley & Sons, Ltd.
A degradation study of cefepime hydrochloride in solutions under various stress conditions by TLC–densitometry
Authors: Dąbrowska Monika , Starek Małgorzata , Krzek Jan , Papp Elżbieta , Król Piotr
Published: July 2014

A rapid, accurate and sensitive thin‐layer chromatography (TLC) method with densitometric detection has been developed and validated for the determination of cefepime in pharmaceuticals. Chromatographic separation was achieved on a silica gel TLC F254 plates with a mobile phase consisting of ethanol–2‐propanol–glacial acetic acid 99.5%–water (4:4:1:3, v/v). Densitometric detection was carried out at wavelength of 266 nm in reflectance/absorbance mode. The validation of the method was found to be satisfactory with high accuracy (from 99.24 to 101.37%) and precision (RSD from 0.06 to 0.36%). Additionally, the stability of cefepime in solution was investigated, including the effect of pH, temperature and incubation time. Favorable retention parameters (Rf, Rs, α) were obtained under the developed conditions, which guaranteed good separation of the studied components. The degradation process of cefepime hydrochloride was described by kinetic and thermodynamic parameters (k, t0.1, t0.5 and Ea). Moreover, the chemical properties of degradation products were characterized by the Rf values, absorption spectra, HPLC‐MS/MS and TLC‐densitometry analysis. As the method could effectively separate the active substance from its main degradation product (1‐methylpyrrolidine), it can be employed as a method to indicate the stability of this drug. Copyright © 2014 John Wiley & Sons, Ltd.
Clinical evaluation of fatigue in Japanese patients with Parkinson's disease
Authors: Tanaka Kenichiro , Wada‐Isoe Kenji , Yamamoto Mikie , Tagashira Shugo , Tajiri Yuki , Nakashita Satoko , Nakashima Kenji
Published: July 2014

Background

Fatigue is a common nonmotor symptom of Parkinson's disease (PD). Although the causes of fatigue were estimated in the previous reports, fatigue is not fully understood. To determine the frequency of and factors related to fatigue in patients with PD, we carried out clinical assessments in our university hospital.

Methods

We used the Japanese version of the Parkinson Fatigue Scale (J‐PFS). The J‐PFS was administered to 110 patients with PD, and a cutoff point of 3.3 was used for the diagnosis of fatigue. Subsequently, demographic characteristics, clinical features, and medications utilized were evaluated to elucidate the factors related to fatigue. In particular, we focused on the relationship between fatigue and gait disorder assessed via the portable gait rhythmogram.

Results

The frequency of fatigue in patients with PD was 52.7%. Univariate analysis revealed that factors significantly associated with fatigue were many motor symptoms and nonmotor symptoms. In addition, multivariate analysis revealed that gait disorder and constipation were independent factors related to fatigue. Furthermore, short‐step walking and bradykinesia in gait disorder had especially a relationship with fatigue.

Conclusions

More than half of our patients were judged having fatigue. Several factors, including motor and nonmotor symptoms, might be related to fatigue in patients with PD.
Mother's choice: An exploration of extended self in infant clothing consumption
Authors: McNeill Lisa , Graham Trelise
Published: July 2014

Consumption behaviour has long been linked to identity and notions of the self, where materialistic behaviours and attitudes are seen as determinants of self‐image. Previous literature has focused on mothers' consumption in general, but not specifically in regard to identity construction through purchasing for an infant. There is a dearth of academic research understanding mothers' consumption behaviour that links identity construction with infant clothing, where the child is part of the mothers' extended self and display of self‐identity. This qualitative, exploratory study provides insight into how mothers construct and express their identity through the extended self, contributing to consumer culture theory. The study examines the purchasing motivations of 14 mothers, utilizing depth interviews and projective association techniques. The findings indicate three predominant drivers underlying mothers' consumption, namely prioritizing the child, self‐representation and conspicuous branding. Copyright © 2014 John Wiley & Sons, Ltd.
RETRACTED: Potential of bone marrow mesenchymal stem cells in management of Alzheimer's disease in female rats
Authors: Salem Ahmed M. , Ahmed Hanaa H. , Atta Hazem M. , Ghazy Mohamed A. , Aglan Hadeer A.
Published: July 2014

Alzheimer's disease (AD) has been called the disease of the century with significant clinical and socioeconomic impacts. Pharmacological treatment has limited efficacy and only provides symptomatic relief without long‐term cure. Accordingly, there is an urgent need to develop novel and effective medications for AD. Stem cell‐based therapy is a promising approach to handling neurodegenerative diseases. Therefore, the current study aimed to explore the possible therapeutic role of single intravenous injection of bone marrow derived mesenchymal stem cells (BM‐MSCs) after 4 months in management of AD in the experimental model. The work also extended to compare the therapeutic potential of BM‐MSCs with 2 conventional therapies of AD; rivastigmine and cerebrolysin administered daily. BM‐MSCs were able to home at the injured brains and produced significant increases in the number of positive cells for choline acetyltransferase (ChAT) and survivin expression, as well as selective AD indicator‐1 (seladin‐1) and nestin gene expression. Histopathological examination indicated that BM‐MSCs could remove beta‐amyloid plaques from hippocampus. Significant improvement in these biomarkers was similar to or better sometimes than the reference drugs, clearly showing the potential therapeutic role of BM‐MSCs against AD through their anti‐apoptotic, neurogenic and immunomodulatory properties.
Gene expression profile analysis of SUDHL6 cells with siRNA‐mediated BCL11A downregulation
Authors: Wu Hong , Gao Yangjun , Ding Li , He Dongmei , Li Yangqiu
Published: July 2014

Our previous study has shown that downregulation of B‐cell chronic lymphocytic leukemia (CLL)/lymphoma11A (BCL11A) gene by small interfering RNA (siRNA) resulted in the growth inhibition and apoptosis of B cell lymphoma cell line SUDHL6. To gain further insight into the molecular mechanisms of this process and identify the differentially expressed genes in SUDHL6 cells after BCL11A downregulation, the global gene expression profile was identified and analyzed using the Affymetrix HG‐U133 Plus 2.0 array. Twenty‐one differentially expressed genes were validated and analyzed from the BCL11A siRNA‐treated SUDHL6 cells. There was a significant dysregulation in the global gene expression of the BCL11A‐suppressed SUDHL6 cells. There were 1903 genes differentially expressed with >2‐fold changes between the BCL11A siRNA‐ and negative control‐transfected cells. Of these, there were 916 upregulated genes and 987 downregulated genes. The differential genes are involved in various molecular functions and signaling pathways. QRT‐PCR validation of the selected differentially expressed genes demonstrated there was a good correlation with the microarray analysis. There was a significant deregulation of expression in the apoptosis‐related genes such as BCL‐2, BCL2L11 and involved in TGFβ, MAPK, WNT signaling pathways after BCL11A was downregulated in SUDHL6 cells. Our results show that the suppression of BCL11A by RNA interference altered gene expression profile of SUDHL6 cells. The apoptosis‐related genes BCL‐2, BCL2L11 and the gene alterations in TGFβ, MAPK, WNT signaling pathways might be important in BCL11A siRNA‐induced apoptosis of SUDHL6 cells, suggesting BCL11A is involved in gene networks associated with apoptosis.
Ruthenium‐Catalyzed Hydroformylation of Alkenes by using Carbon Dioxide as the Carbon Monoxide Source in the Presence of Ionic Liquids
Authors: Ali Meher , Gual Aitor , Ebeling Günter , Dupont Jairton
Published: July 2014

The reaction of [BMI⋅Cl] (BMI=1‐butyl‐3‐methylimidazolium) or [BMMI⋅Cl] (BMMI=3‐butyl‐1,2‐dimethylimidazolium) with Ru3(CO)12 generates Ru–hydride–carbonyl–carbene species in situ that are efficient catalysts for a reverse water gas shift/hydroformylation/hydrogenation cascade reaction. The addition of H3PO4 increased the catalytic activity of the first step (i.e., the hydrogenation of CO2 to CO). Under the optimized reaction conditions [120 °C and 6.0 MPa CO2/H2 (1:1) for 17 h], cyclohexene and 2,2‐disubstituted alkenes were easily functionalized to alcohols through sequential hydroformylation/carbonyl reduction.
Combined EXAFS and DFT Structure Calculations Provide Structural Insights into the 1:1 Multi‐Histidine Complexes of CuII, CuI, and ZnII with the Tandem Octarepeats of the Mammalian Prion Protein
Authors: Pushie M. Jake , Nienaber Kurt H. , McDonald Alex , Millhauser Glenn L. , George Graham N.
Published: July 2014

The metal‐coordinating properties of the prion protein (PrP) have been the subject of intense focus and debate since the first reports of its interaction with copper just before the turn of the century. The picture of metal coordination to PrP has been improved and refined over the past decade, but structural details of the various metal coordination modes have not been fully elucidated in some cases. In the present study, we have employed X‐ray absorption near‐edge spectroscopy as well as extended X‐ray absorption fine structure (EXAFS) spectroscopy to structurally characterize the dominant 1:1 coordination modes for CuII, CuI, and ZnII with an N‐terminal fragment of PrP. The PrP fragment corresponds to four tandem repeats representative of the mammalian octarepeat domain, designated as OR4, which is also the most studied PrP fragment for metal interactions, making our findings applicable to a large body of previous work. Density functional theory (DFT) calculations have provided additional structural and thermodynamic data, and candidate structures have been used to inform EXAFS data analysis. The optimized geometries from DFT calculations have been used to identify potential coordination complexes for multi‐histidine coordination of CuII, CuI, and ZnII in an aqueous medium, modelled using 4‐methylimidazole to represent the histidine side chain. Through a combination of in silico coordination chemistry as well as rigorous EXAFS curve‐fitting, using full multiple scattering on candidate structures derived from DFT calculations, we have characterized the predominant coordination modes for the 1:1 complexes of CuII, CuI, and ZnII with the OR4 peptide at pH 7.4 at atomic resolution, which are best represented as square‐planar [CuII(His)4]2+, digonal [CuI(His)2]+, and tetrahedral [ZnII(His)3(OH2)]2+, respectively.
Ultra‐Small Plutonium Oxide Nanocrystals: An Innovative Material in Plutonium Science
Authors: Hudry Damien , Apostolidis Christos , Walter Olaf , Janßen Arne , Manara Dario , Griveau Jean‐Christophe , Colineau Eric , Vitova Tonya , Prüßmann Tim , Wang Di , Kübel Christian , Meyer Daniel
Published: July 2014

Apart from its technological importance, plutonium (Pu) is also one of the most intriguing elements because of its non‐conventional physical properties and fascinating chemistry. Those fundamental aspects are particularly interesting when dealing with the challenging study of plutonium‐based nanomaterials. Here we show that ultra‐small (3.2±0.9 nm) and highly crystalline plutonium oxide (PuO2) nanocrystals (NCs) can be synthesized by the thermal decomposition of plutonyl nitrate ([PuO2(NO3)2]⋅3 H2O) in a highly coordinating organic medium. This is the first example reporting on the preparation of significant quantities (several tens of milligrams) of PuO2 NCs, in a controllable and reproducible manner. The structure and magnetic properties of PuO2 NCs have been characterized by a wide variety of techniques (powder X‐ray diffraction (PXRD), X‐ray absorption fine structure (XAFS), X‐ray absorption near edge structure (XANES), TEM, IR, Raman, UV/Vis spectroscopies, and superconducting quantum interference device (SQUID) magnetometry). The current PuO2 NCs constitute an innovative material for the study of challenging problems as diverse as the transport behavior of plutonium in the environment or size and shape effects on the physics of transuranium elements.
Germanium Quantum Dots Embedded in N‐Doping Graphene Matrix with Sponge‐Like Architecture for Enhanced Performance in Lithium‐Ion Batteries
Authors: Qin Jinwen , Wang Xia , Cao Minhua , Hu Changwen
Published: July 2014

Germanium quantum dots embedded in a nitrogen‐doped graphene matrix with a sponge‐like architecture (Ge/GN sponge) are prepared through a simple and scalable synthetic method, involving freeze drying to obtain the Ge(OH)4/graphene oxide (GO) precursor and subsequent heat reduction treatment. Upon application as an anode for the lithium‐ion battery (LIB), the Ge/GN sponge exhibits a high discharge capacity compared with previously reported N‐doped graphene. The electrode with the as‐synthesized Ge/GN sponge can deliver a capacity of 1258 mAh g−1 even after 50 charge/discharge cycles. This improved electrochemical performance can be attributed to the pore memory effect and highly conductive N‐doping GN matrix from the unique sponge‐like structure.
Beyond PEG2000: Synthesis and Functionalisation of Monodisperse PEGylated Homostars and Clickable Bivalent Polyethyleneglycols
Authors: Székely György , Schaepertoens Marc , Gaffney Piers R. J. , Livingston Andrew G.
Published: July 2014

A new strategy to access highly monodisperse, heterobifunctional linear polyethylenglycols (PEGs) has been designed. This was built around unidirectional, iterative chain extension of a 3‐arm PEG homostar. A mono‐(4,4′‐dimethoxytriphenylmethyl) octagol building block, DmtrO‐EG8‐OH, was constructed from tetragol. After six rounds of chain extension, the monodisperse homostar reached the unprecedented length of 56 monomers per arm (PEG2500). The unique architecture of the synthetic platform greatly assisted in facilitating and monitoring reaction completion, overcoming kinetic limitations, chromatographic purification of intermediates, and analytical assays. After chain terminal derivatisation, mild hydrogenolytic cleavage of the homostar hub provided heterobifunctional linear EG56 chains with a hydroxyl at one end, and either a toluene sulfonate, or a tert‐butyl carboxylate ester at the other. A range of heterobifunctional, monodisperse PEGs was then prepared having useful cross‐linking functionalities (‐OH, ‐COOH, ‐NH2, ‐N3) at both ends. A rapid preparation of polydisperse PEG homostars, free of multiply cross‐linked chains, is also described. The above approach should be extendable to other high value oligomers and polymers.
A New Class of Homogeneous Visible‐Light Photocatalysts: Molecular Cerium Vanadium Oxide Clusters
Authors: Seliverstov Andrey , Streb Carsten
Published: July 2014

The first systematic access to molecular cerium vanadium oxides is presented. A family of structurally related, di‐cerium‐functionalized vanadium oxide clusters and their use as visible‐light‐driven photooxidation catalysts is reported. Comparative analyses show that photocatalytic activity is controlled by the cluster architecture. Increased photoreactivity of the cerium vanadium oxides in the visible range compared with nonfunctionalized vanadates is observed. Based on the recent discovery of the first molecular cerium vanadate cluster, (nBu4N)2[(Ce(dmso)3)2V12O33Cl]⋅2 DMSO (1), two new di‐cerium‐containing vanadium oxide clusters [(Ce(dmso)4)2V11O30Cl]⋅DMSO (2) and [(Ce(nmp)4)2V12O32Cl]⋅NMP⋅Me2CO (3; NMP=N‐methyl‐2‐pyrrolidone) were obtained by using a novel fragmentation and reassembly route. Pentagonal building units {(V)M5} (M=V, Ce) reminiscent of “Müller‐type” pentagons are observed in 2 and 3. Compounds 1–3 feature high visible‐light photooxidative activity, and quantum efficiencies >10 % for indigo photooxidation are observed. Photocatalytic performance increases in the order 1<3<2. Mechanistic studies show that the irradiation wavelength and the presence of oxygen strongly affect photoreactivity. Initial findings suggest that the photooxidation mechanism proceeds by intermediate formation of hydroxyl radicals. The findings open new avenues for the bottom‐up design of sunlight‐driven photocatalysts.
Impact of Ground‐ and Excited‐State Aromaticity on Cyclopentadiene and Silole Excitation Energies and Excited‐State Polarities
Authors: Jorner Kjell , Emanuelsson Rikard , Dahlstrand Christian , Tong Hui , Denisova Aleksandra V. , Ottosson Henrik
Published: July 2014

A new qualitative model for estimating the properties of substituted cyclopentadienes and siloles in their lowest ππ* excited states is introduced and confirmed through quantum chemical calculations, and then applied to explain earlier reported experimental excitation energies. According to our model, which is based on excited‐state aromaticity and antiaromaticity, siloles and cyclopentadienes are cross‐hyperconjugated “aromatic chameleons” that adapt their electronic structures to conform to the various aromaticity rules in different electronic states (Hückel’s rule in the π2 electronic ground state (S0) and Baird’s rule in the lowest ππ* excited singlet and triplet states (S1 and T1)). By using pen‐and‐paper arguments, one can explain polarity changes upon excitation of substituted cyclopentadienes and siloles, and one can tune their lowest excitation energies by combined considerations of ground‐ and excited‐state aromaticity/antiaromaticity effects. Finally, the “aromatic chameleon” model can be extended to other monocyclic compound classes of potential use in organic electronics, thereby providing a unified view of the S0, T1, and S1 states of a range of different cyclic cross‐π‐conjugated and cross‐hyperconjugated compound classes.
Molecular Parameters and Transmembrane Transport Mechanism of Imidazolium‐Functionalized Binols
Authors: Vidal Marc , Schmitzer Andreea
Published: July 2014

We describe the molecular parameters governing the transmembrane activity of imidazolium‐functionalized anion transporters and present a detailed mechanistic study. These ionophores adopt a mobile‐carrier mechanism for short methyl and butyl chains, a combined mobile‐carrier/transmembrane‐pore mechanism for octyl and dodecyl chains, and form transmembrane aggregates for hexadecyl chains.
Vicinal Solvent Effect on Supramolecular Gelation: Alcohol Controlled Topochemical Reaction and the Toruloid Nanostructure
Authors: Wang Xiufeng , Liu Minghua
Published: July 2014

Although solvent is the major component of the gel, it still remains unclear how the solvent molecules take part in the formation of the gel nanostructures in many gels. In this study it was observed that the vicinal effect on gel formation as well as their nanostructures, that is, the vicinal solvent molecules to the gelator, determine the molecular packing and their subsequent structures and properties. A naphthylacryl‐conjugated L‐glutamide gelator was found to form organogels in various solvents and nanofiber structures. While the nanofibers from other solvents could not show any further reaction, the gel from the alcohol could undergo topochemical [2+2] cycloaddition under photoirradiation and resulted in toruloid nanostructures. Various pure alcohol solvents from methanol to pentanol were found to show a similar property. Interestingly, switching from a single alcohol solvent to mixed solvents of alcohol with miscible or immiscible non‐alcohol solvents could still cause the same change, showing the vicinal effect of alcohol on controlling the molecular packing as well as the structural transformation. More interestingly, when nanofiber xerogel, obtained from non‐alcohol solvents, was exposed to alcohol vapor, the nanofiber was transferred into nanotoruloid. These results provide a new insight into the gelator–solvent interaction in soft gels.
Elemental F2 with Transannular Dienes: Regioselectivities and Mechanisms
Authors: Ponomarenko Maxim V. , Serguchev Yuriy A. , Hirschberg Markus E. , Röschenthaler Gerd‐Volker , Fokin Andrey A.
Published: July 2014

Three reaction paths, namely, molecule‐induced homolytic, free radical, and electrophilic, were modeled computationally at the MP2 level of ab initio theory and studied experimentally for the reaction of F2 with the terminal dienes of bicyclo[3.3.1]nonane series. The addition of fluorine is accompanied by transannular cyclization to the adamantane derivatives in which strong evidence for the electrophilic mechanism both in nucleophilic (acetonitrile) and non‐nucleophilic (CFCl3, CHCl3) solvents were found. The presence of KF in CFCl3 and CHCl3 facilitates the addition and substantially reduces the formation of tar products.
2‐Acylpyrroles as Mono‐anionic O,N‐Chelating Ligands in Silicon Coordination Chemistry
Authors: Kämpfe Alexander , Brendler Erica , Kroke Edwin , Wagler Jörg
Published: July 2014

Kryptopyrrole (2,4‐dimethyl‐3‐ethylpyrrole) was acylated with, for example, benzoyl chloride to afford 2‐benzoyl‐3,5‐dimethyl‐4‐ethylpyrrole (L1H). With SiCl4 this ligand reacts under liberation of HCl and formation of the complex L12SiCl2. In related reactions with HSiCl3 or H2SiCl2, the same chlorosilicon complex is formed under liberation of HCl and H2 or liberation of H2, respectively. The chlorine atoms of L12SiCl2 can be replaced by fluoride and triflate using ZnF2 and Me3Si‐OTf, respectively. The use of a supporting base (triethylamine) is required for the complexation of phenyltrichlorosilane and diphenyldichlorosilane. The complexes L12SiCl2, L12SiF2, L12Si(OTf)2, L12SiPhCl, and L12SiPh2 exhibit various configurations of the octahedral silicon coordination spheres (i.e. cis or trans configuration of the monodentate substituents, different orientations of the bidentate chelating ligands relative to each other). Furthermore, cationic silicon complexes L13Si+ and L12SiPh+ were synthesized by chloride abstraction with GaCl3. In contrast, reaction of L12SiCl2 with a third equivalent of L1H in the presence of excess triethylamine produced a charge‐neutral hexacoordinate Si complex with a new tetradentate chelating ligand which formed by Si‐templated CC coupling of two ligands L1.
Cyclometalated Mono‐ and Dinuclear IrIII Complexes with “Click”‐Derived Triazoles and Mesoionic Carbenes
Authors: Maity Ramananda , Hohloch Stephan , Su Cheng‐Yong , van der Meer Margarethe , Sarkar Biprajit
Published: July 2014

Orthometalation at IrIII centers is usually facile, and such orthometalated complexes often display intriguing electronic and catalytic properties. By using a central phenyl ring as CH activation sites, we present here mono‐ and dinuclear IrIII complexes with “click”‐derived 1,2,3‐triazole and 1,2,3‐triazol‐5‐ylidene ligands, in which the wingtip phenyl groups in the aforementioned ligands are additionally orthometalated and bind as carbanionic donors to the IrIII centers. Structural characterization of the complexes reveal a piano stool‐type of coordination around the metal centers with the “click”‐derived ligands bound either with C^N or C^C donor sets to the IrIII centers. Furthermore, whereas bond localization is observed within the 1,2,3‐triazole ligands, a more delocalized situation is found in their 1,2,3‐triazol‐5‐ylidene counterparts. All complexes were subjected to catalytic tests for the transfer hydrogenation of benzaldehyde and acetophenone. The dinuclear complexes turned out to be more active than their mononuclear counterparts. We present here the first examples of stable, isomer‐pure, dinuclear cyclometalated IrIII complexes with poly‐mesoionic‐carbene ligands.
Reactions of Diaryldibromodisilenes with N‐Heterocyclic Carbenes: Formation of Formal Bis‐NHC Adducts of Silyliumylidene Cations
Authors: Agou Tomohiro , Hayakawa Naoki , Sasamori Takahiro , Matsuo Tsukasa , Hashizume Daisuke , Tokitoh Norihiro
Published: July 2014

Reactions of stable 1,2‐dibromodisilenes ((E)‐Ar(Br)SiSi(Br)Ar) with N‐heterocyclic carbenes (NHC) afforded NHC–arylbromosilylene adducts or bromide salts of the corresponding bis‐NHC adducts of the formal arylsilyliumylidene cations ([ArSi:]+). In some cases, an NHC was able to replace a bromide anion in the coordination sphere of the arylbromosilylene–NHC adduct.
Redox Divergent Synthesis of Fawcettimine‐Type Lycopodium Alkaloids
Authors: Zaimoku Hisaaki , Taniguchi Tsuyoshi
Published: July 2014

A new approach for synthesis of fawcettimine‐type Lycopodium alkaloids is described. A divergent strategy was achieved by applying stereoselective Diels–Alder reaction followed by redox‐controlled elaboration. Eventually, (−)‐8‐deoxyserratinine, (+)‐fawcettimine, (−)‐lycopoclavamine‐A, (−)‐serratine, (−)‐lycopoclavamine‐B and (−)‐serratanidine were successfully accessed.
Enantioselective Construction of Quaternary Stereogenic Carbon Atoms by the Lewis Base Catalyzed Additions of Silyl Ketene Imines to Aldehydes
Authors: Denmark Scott E. , Wilson Tyler W. , Burk Matthew T.
Published: July 2014

Silyl ketene imines derived from a variety of α‐branched nitriles have been developed as highly useful reagents for the construction of quaternary stereogenic centers via the aldol addition reaction. In the presence of SiCl4 and the catalytic action of a chiral phosphoramide, silyl ketene imines undergo extremely rapid and high yielding addition to a wide variety of aromatic aldehydes with excellent diastereo‐ and enantioselectivity. Of particular note are the high yields and selectivities obtained from electron‐rich, electron‐poor, and hindered aldehydes. Linear aliphatic aldehydes did react with good diastereo‐ and enantioselectivity in the presence of nBu4N+I−, but branched aldehydes were much less reactive. Semiempirical calculations provided a rationalization of the observed diastereo‐ and enantioselectivity via open transitions states.
Two Pentasilahousanes Fused Together
Authors: Tsurusaki Akihiro , Koganezono Makoto , Otsuka Kyohei , Ishida Shintaro , Kyushin Soichiro
Published: July 2014

The organosilicon cluster 1 with two pentasilahousanes fused together was synthesized by the reduction of 1,1,3‐trichlorocyclotetrasilane. This reaction involves dimerization and rearrangement of the silicon skeleton. The structure and properties of 1 were studied by X‐ray crystallographic and spectroscopic analyses.
Effect of Residual Endosulfan on Pseudomonas aeruginosa NCIM 2036
Authors: Patil Savita B. , Niljikar Sneha C. , Ghosh Jai S.
Published: July 2014

Endosulfan has been banned in several developed nations; it is still the farmers’ favorite in many developing nations. The farmers use this pesticide indiscriminately resulting in high residues in soil. The objective of this investigation is not to reestablish the findings of other researchers regarding the residual endosulfan quantity in different agricultural soils of this country; neither is it aimed to find out the biodegradative mechanism of the compound by microorganisms. The investigation aims at studying the biomagnification carried out by a heterotrophic soil organism: Pseudomonas aeruginosa NCIM 2036. The pesticide has been found inside the microorganism resulting in longer lag phase of growth of the organisms which ultimately has deleterious effect on mineral cycling in soil, affecting crop yield.
Bioequivalence study with lapatinib powder for oral suspension and the original tablet formulation in cancer patients
Authors: Koch Kevin M. , Ferron‐Brady Geraldine , Lemmon Colleen , Cartee Leanne , Hollyfield Hedy , D'Amelio Anthony M. , Piepszak Alexandra , Swaby Ramona F. , Curran David , Arya Niki
Published: July 2014

Lapatinib is approved for use in various therapeutic combinations for treating metastatic breast cancers that over‐express HER2. To deliver the approved doses, up to six large tablets need to be ingested with the current 250‐mg tablets. For ease of ingestion, a powder for oral suspension was developed. This study was an open‐label, randomized, adaptive design, two‐period crossover bioequivalence study of the powder for suspension relative to the commercial tablet at steady state following once daily dosing for 7 days in patients with advanced cancer. To minimize the number of cancer patients required for a pivotal bioequivalence study (144 in this case), a four‐stage adaptive group sequential design with interim analyses after every 36 subjects was implemented to allow for early termination. Bioequivalence for the oral suspension relative to the commercial tablet was demonstrated in both the first (and only) interim analysis and the final analysis, as the 90% confidence intervals for the treatment comparison ratios for both AUC0–24 and Cmax were contained within the acceptance criteria (0.80, 1.25). Additionally, there was no statistical difference in tlag or tmax, suggesting no difference in the absorption rate between treatments. There were no unexpected safety findings during this study.
Effects of ketoconazole on the pharmacokinetics of lenvatinib (E7080) in healthy participants
Authors: Shumaker Robert , Aluri Jagadeesh , Fan Jean , Martinez Gresel , Thompson Gary A. , Ren Min
Published: July 2014

Background

Lenvatinib is an oral, multitargeted, tyrosine kinase inhibitor under clinical investigation in solid tumors. In vitro evidence indicates that lenvatinib metabolism may be modulated by ketoconazole, an inhibitor of CYP3A4 and p‐glycoprotein.

Methods

In this Phase I, single‐center, randomized, open‐label, two‐period, crossover study, healthy adults (18–55 years; N = 18) were randomized to one of two sequences (ketoconazole → placebo or vice versa). Ketoconazole (400 mg) or placebo was administered orally once daily for 18 days; a 5 mg dose of lenvatinib was orally administered on Day 5 of each treatment period. Blood samples were collected over 14 days and lenvatinib plasma concentrations measured by high‐performance liquid chromatography/tandem mass spectrometry.

Results

Systemic exposure to lenvatinib increased slightly (15–19%) with coadministration of ketoconazole. Although the 90% confidence interval (CI) for area under the plasma concentration–time curve (AUC) was within the prespecified bioequivalence interval of 80–125%, Cmax slightly exceeded the 125% CI bound (134%). No changes in tmax, tlag, or t½ were observed. Thirteen subjects (72%) experienced treatment‐emergent adverse events (11 mild, 2 moderate), most commonly headache (22%) and diarrhea (17%).

Conclusions

Lenvatinib exposure was slightly increased by ketoconazole; however, the magnitude of the change was relatively small, and likely not clinically meaningful.
Design space exploration of SW beamformer on GPU
Authors: Phuong Thi Yen , Lee Jeong‐Gun
Published: July 2014

Ultrasound imaging has become one of the most widely used modalities in medical diagnosis today. However, real‐time ultrasound imaging requires large amount of data transfer and massive computation and therefore mainly relies on a complex dedicated hardware system. A recent trend of a graphics processing unit (GPU) based software‐based approach offers the advantages of flexibility and quick implementation. The GPUs have been reported as excellent accelerators across a wide range of applications. For best exploiting outstanding computational power and high memory bandwidth of a GPU, the paper explores the design space of implementing an ultrasound beamformer on a GPU platform. The design spaces are expanded by applying different optimization strategies to the beamformer on a GPU platform, and we also discuss the performance evaluation results on the various GPUs whose architectural characteristics are different to each others. The performance analysis shows that by optimizing CUDA code, our real‐time‐GPU‐based beamformer can be successfully implemented with 181 frames per second (fps) and speedup of 230.6X compared with the single‐threaded implementation on a high‐performance CPU platform. Copyright © 2014 John Wiley & Sons, Ltd.
Modelling the relationship between catchment attributes and wetland water quality in Japan
Authors: Haidary Azam , Jabbarian Amiri Bahman , Adamowski Jan , Fohrer Nicola , Nakane Kaneyuki
Published: July 2014

The influence of catchment attributes has been examined to find out whether variations in water quality indicators [electrical conductivity (EC), pH, turbidity, dissolved oxygen (DO), total dissolved solid (TDS), total nitrogen (TN), dissolved organic nitrogen (DON), dissolved inorganic nitrogen (DIN), temperature and nitrogen] could be explained by them for 24 wetlands in west Japan. Urban areas (%) were positively (P ≤ 0.05) correlated with EC (r = 0.67), TDS (r = 0.69), TN (r = 0.92), DON (r = 0.60), [NH4+] (r = 0.47) and with [NO2−] (r = 0.50). Forest areas (%) were inversely (P ≤ 0.05) correlated with EC (r = −0.62), TDS (r = −0.68), TN (r = −0.68) and [NH4+] (r = −0.55) and with DON (r = −0.43). Agricultural area (%) was positively (P ≤ 0.05) correlated with EC (r = 0.40), TDS (r = 0.45), TN (r = 0.44) and [NH4+] (r = 0.56) and with both areas (%) of grey lowland soil (r = 0.60) and diluvial sand (r = 0.58). Area (%) of regosol was positively correlated with DO (r = 0.42) but inversely with DON (r = −0.44, P ≤ 0.05). Rhyolite was positively (P ≤ 0.05) correlated with the TN (r = 0.46) but inversely with DON (r = −0.49) and [NH4+] (r = −0.47). Regression models were developed for the water quality indicators including EC (r2 = 0. 62), (r2 = 0.90), (r = 0.52), TN (r = 0.86), DIN (r2 = 0.74) and DON (r2 = 0.54) at 0.01 ≤ P ≤ 0.05. In the models, no significant contribution has been observed for catchment geometric features of the wetlands on water quality indicators. Copyright © 2014 John Wiley & Sons, Ltd.