bluuebunny/crossref_metadata_2025 huggingface dataset:
The Origin of the Catalytic Activity of a Metal Hydride in CO2 Reduction
Authors: Kato Shunsuke , Matam Santhosh Kumar , Kerger Philipp , Bernard Laetitia , Battaglia Corsin , Vogel Dirk , Rohwerder Michael , Züttel Andreas
Published: April 2016

Atomic hydrogen on the surface of a metal with high hydrogen solubility is of particular interest for the hydrogenation of carbon dioxide. In a mixture of hydrogen and carbon dioxide, methane was markedly formed on the metal hydride ZrCoHx in the course of the hydrogen desorption and not on the pristine intermetallic. The surface analysis was performed by means of time‐of‐flight secondary ion mass spectroscopy and near‐ambient pressure X‐ray photoelectron spectroscopy, for the in situ analysis. The aim was to elucidate the origin of the catalytic activity of the metal hydride. Since at the initial stage the dissociation of impinging hydrogen molecules is hindered by a high activation barrier of the oxidised surface, the atomic hydrogen flux from the metal hydride is crucial for the reduction of carbon dioxide and surface oxides at interfacial sites.
An Electron‐Poor C64 Nanographene by Palladium‐Catalyzed Cascade C−C Bond Formation: One‐Pot Synthesis and Single‐Crystal Structure Analysis
Authors: Seifert Sabine , Shoyama Kazutaka , Schmidt David , Würthner Frank
Published: April 2016

Herein, we report the one‐pot synthesis of an electron‐poor nanographene containing dicarboximide groups at the corners. We efficiently combined palladium‐catalyzed Suzuki–Miyaura cross‐coupling and dehydrohalogenation to synthesize an extended two‐dimensional π‐scaffold of defined size in a single chemical operation starting from N‐(2,6‐diisopropylphenyl)‐4,5‐dibromo‐1,8‐naphthalimide and a tetrasubstituted pyrene boronic acid ester as readily accessible starting materials. The reaction of these precursors under the conditions commonly used for Suzuki–Miyaura cross‐coupling afforded a C64 nanographene through the formation of ten C−C bonds in a one‐pot process. Single‐crystal X‐ray analysis unequivocally confirmed the structure of this unique extended aromatic molecule with a planar geometry. The optical and electrochemical properties of this largest ever synthesized planar electron‐poor nanographene skeleton were also analyzed.
Das Bis(pentafluorethyl)germylen‐Trimethylphosphan‐Addukt, (C2F5)2Ge⋅PMe3 – Charakterisierung, Ligandeigenschaften und Reaktivität
Authors: Pelzer Stefanie , Neumann Beate , Stammler Hans‐Georg , Ignat'ev Nikolai , Hoge Berthold
Published: April 2016

Wir beschreiben hier die Synthese des Germylen‐Phosphan‐Adduktes (C2F5)2Ge⋅PMe3 ausgehend von (C2F5)3GeH; dabei wurde dieses in überschüssigem PMe3 erhitzt, was zur reduktiven Eliminierung von C2F5H führte. Die Molekülstruktur des Addukts im Festkörper wurde röntgenographisch bestimmt und mit Ergebnissen quantenmechanischer Rechnungen verglichen. Die Eigenschaften als Ligand wurden mithilfe IR‐spektroskopischer Untersuchungen des CO‐Bereichs von [Ni0(CO)3{Ge(C2F5)2(PMe3)}] abgeleitet. Damit wurde (C2F5)2Ge⋅PMe3 anhand des elektronischen Parameters nach Tolman als ein mit PMe3 vergleichbarer π‐Akzeptorligand eingeordnet. Des Weiteren wurden eine [2+4]‐Cycloaddition mit 2,3‐Dimethyl‐1,3‐butadien sowie Insertionsreaktionen in σ‐Bindungen beobachtet. Ein Beispiel für die letztgenannten Reaktionen ist die Aktivierung der C‐Cl‐Bindung in Dichlormethan unter Bildung des Phosphoniumylidkomplexes [(C2F5)2Cl2Ge‐CH2PMe3], der vollständig röntgenographisch charakterisiert wurde.
Enzyme‐ and Ruthenium‐Catalyzed Enantioselective Transformation of α‐Allenic Alcohols into 2,3‐Dihydrofurans
Authors: Yang Bin , Zhu Can , Qiu Youai , Bäckvall Jan‐E.
Published: April 2016

An efficient one‐pot method for the enzyme‐ and ruthenium‐catalyzed enantioselective transformation of α‐allenic alcohols into 2,3‐dihydrofurans has been developed. The method involves an enzymatic kinetic resolution and a subsequent ruthenium‐catalyzed cycloisomerization, which provides 2,3‐dihydrofurans with excellent enantioselectivity (up to >99 % ee). A ruthenium carbene species was proposed as a key intermediate in the cycloisomerization.
Enzymatic Macrocyclization of 1,2,3‐Triazole Peptide Mimetics
Authors: Oueis Emilia , Jaspars Marcel , Westwood Nicholas J. , Naismith James H.
Published: April 2016

The macrocyclization of linear peptides is very often accompanied by significant improvements in their stability and biological activity. Many strategies are available for their chemical macrocyclization, however, enzyme‐mediated methods remain of great interest in terms of synthetic utility. To date, known macrocyclization enzymes have been shown to be active on both peptide and protein substrates. Here we show that the macrocyclization enzyme of the cyanobactin family, PatGmac, is capable of macrocyclizing substrates with one, two, or three 1,4‐substituted 1,2,3‐triazole moieties. The introduction of non‐peptidic scaffolds into macrocycles is highly desirable in tuning the activity and physical properties of peptidic macrocycles. We have isolated and fully characterized nine non‐natural triazole‐containing cyclic peptides, a further ten molecules are also synthesized. PatGmac has now been shown to be an effective and versatile tool for the ring closure by peptide bond formation.
Astringent Mouthfeel as a Consequence of Lubrication Failure
Authors: Ma Shuanhong , Lee Haeshin , Liang Yongmin , Zhou Feng
Published: April 2016

Herein, we systematically investigate the origin of astringent mouthfeel when we eat unripe fruits, drink coffee or tea, from the perspective of lubrication by simulating the dynamic weak interaction on the tongue with model protein (mucoprotein, MP) and polyphenolic compounds (tannic acid, TA). Astringency was due to the protein‐mediated lubrication failure when encountering polyphenolic molecules that normally exist, for example in unripe fruits, coffee, tea. The underlying molecular mechanism of oral tribology is widely present in nature and enables us to engineer a tongue‐like polyacrylamide composite hydrogel that exhibits high TA sensitivity and to develop a scientific strategy for catching slippery fish using TA‐containing gloves. These results provide novel and useful insights into the failure of biological boundary lubrication on soft tissue surface with the adsorbed proteins.
Total Synthesis of (−)‐Daphenylline
Authors: Yamada Ryosuke , Adachi Yohei , Yokoshima Satoshi , Fukuyama Tohru
Published: April 2016

Total synthesis of (−)‐daphenylline, a hexacyclic Daphniphyllum alkaloid, was achieved. Construction of the tricyclic DEF ring system was initiated by asymmetric Negishi coupling followed by an intramolecular Friedel–Crafts reaction. Installation of a side chain onto the tricyclic core was carried out through Sonogashira coupling, stereocontrolled Claisen rearrangement by taking advantage of the characteristic conformation of the tricyclic DEF core, and the stereoselective alkylation of a lactone. After the introduction of a glycine unit, the ABC ring system was stereoselectively constructed through intramolecular cycloaddition of the cyclic azomethine ylide.
Designed Assembly of Heterometallic Cluster Organic Frameworks Based on Anderson‐Type Polyoxometalate Clusters
Authors: Li Xin‐Xiong , Wang Yang‐Xin , Wang Rui‐Hu , Cui Cai‐Yan , Tian Chong‐Bin , Yang Guo‐Yu
Published: April 2016

A new approach to prepare heterometallic cluster organic frameworks has been developed. The method was employed to link Anderson‐type polyoxometalate (POM) clusters and transition‐metal clusters by using a designed rigid tris(alkoxo) ligand containing a pyridyl group to form a three‐fold interpenetrated anionic diamondoid structure and a 2D anionic layer, respectively. This technique facilitates the integration of the unique inherent properties of Anderson‐type POM clusters and cuprous iodide clusters into one cluster organic framework.
Identification of the Key Enzyme of Roseoflavin Biosynthesis
Authors: Schwarz Julia , Konjik Valentino , Jankowitsch Frank , Sandhoff Roger , Mack Matthias
Published: April 2016

The bacteria Streptomyces davawensis and Streptomyces cinnabarinus produce roseoflavin, the only known natural riboflavin (vitamin B2) analogue with antibiotic activity. Roseoflavin can be considered a natural antimetabolite and has been postulated to be biosynthesized from riboflavin via the key intermediate 8‐demethyl‐8‐aminoriboflavin (AF). The required site‐specific substitution of one of the methyl groups on the dimethylbenzene ring of riboflavin by an amino group (to give AF) is challenging. The pathway from riboflavin to AF has remained elusive, and the corresponding enzyme/s was/were unknown. Herein, we show by systematic gene deletion, heterologous gene expression, and biochemical studies that the enzyme specified by the gene BN159_7989 from S. davawensis is able to carry out a whole set of chemical reactions starting from riboflavin‐5′‐phosphate to give the final product 8‐demethyl‐8‐aminoriboflavin‐5′‐phosphate (AFP).
Magnetic iron oxide nanoparticles–N‐heterocyclic carbene–palladium(II): a new, efficient and robust recyclable catalyst for Mizoroki–Heck and Suzuki–Miyaura coupling reactions
Authors: Hajipour Abdol R. , Tadayoni Nayereh S. , Khorsandi Zahra
Published: April 2016

A new and efficient nanoparticle–N‐heterocyclic carbene–palladium complex was synthesized and characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, field emission scanning electron microscopy, energy‐dispersive X‐ray analysis, X‐ray diffraction, transmission electron microscopy, elemental analysis, inductively coupled plasma analysis and vibrating sample magnetometry. This catalytic system was found to be a highly active catalyst in the Mizoroki–Heck and Suzuki–Miyaura cross‐coupling reactions. These reactions were best performed in dimethylformamide and water, respectively, in the presence of only 0.054 mol% of palladium under mild conditions. Moreover, the catalyst could be recovered easily and reused at least ten times without any considerable loss of its catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.
Preparation, optimization, and characterization of simvastatin nanoparticles by electrospraying: An artificial neural networks study
Authors: Imanparast Fatemeh , Faramarzi Mohammad Ali , Paknejad Maliheh , Kobarfard Farzad , Amani Amir , Doosti Mohmood
Published: April 2016

The purpose of this study was to determine major factors impacting the size of simvastatin (SIM)‐loaded poly(d, l‐lactic‐co‐glycolide) (PLGA) nanoparticles (NPs) that was prepared using electrospraying. Three variables including concentration of polymer and salt as well as solvent flow rate were used as input variables. Size of NPs was considered as output variable. For the first time, our findings using a systematic and experimental approach, showed the importance of salt concentration as the dominant factor determining the size with a sharp and reverse effect. Optimum formulation (i.e., flow rate 0.08 mL h−1, polymer concentration 0.7 w/v %, and salt concentration 0.8 mM) was then evaluated for aqueous solubility, encapsulation efficiency, particle size, in vitro drug release pattern and cytotoxicity. A very appreciable encapsulation efficiency (90.3%) as well as sustained release profile, considerable enhancement in aqueous solubility (∼5.8 fold) and high IC50 (>600 µM of SIM‐loaded PLGA NPs) indicated PLGA as a promising nanocarrier for SIM. The optimum formulation had particle size, zeta potential value, polydispersity index (PDI) and drug loading of 166 nm, +3 mV, 0.62 and 9%, respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43602.
Fabrication and characterization of novel zirconia filled glass fiber reinforced polyester hybrid composites
Authors: Munawar Muhammad Azeem , Khan Shahzad Maqsood , Gull Nafisa , Shafiq Muhammad , Islam Atif , Zia Saba , Sabir Aneela , Ghouri Awais Sattar , Butt Muhammad Taqi Zahid , Jamil Tahir
Published: April 2016

Novel hybrid glass fiber reinforced polyester composites (GFRPCs) filled with 1‐5 wt % microsized zirconia (ZrO2) particles, were fabricated by hand lay‐up process followed by compression molding and evaluated their physical, mechanical and thermal behaviors. The consumption of styrene in cured GFRPCs was confirmed by Fourier transform infrared spectroscopy. The potential implementation of ZrO2 particles lessened the void contents marginally and substantially enhanced the mechanical and thermal properties in the resultant hybrid composites. The GFRPCs filled with 4 wt % ZrO2 illustrated noteworthy improvement in tensile strength (66.672 MPa) and flexural strength (67.890 MPa) while with 5 wt % ZrO2 showed 63.93% rise in hardness, respectively, as compared to unfilled GFRPCs. Physical nature of polyester matrix for composites and an improved glass transition temperature (Tg) from 103 to 112 °C was perceived by differential scanning calorimetry thermograms. Thermogravimetric analysis revealed that the thermal stability of GFRPCs was remarkably augmented with the addition of ZrO2. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43615.
Biorenewable blends of polyamide‐4,10 and polyamide‐6,10
Authors: Moran Christopher S. , Barthelon Agathe , Pearsall Andrew , Mittal Vikas , Dorgan John R.
Published: April 2016

Biobased polymers hold the promise of greatly improved sustainability metrics. In this study, semicrystalline polymer blends are formulated between two partially biorenewable polyamides. Polyamide 4,10 (PA410) is melt mixed with polyamide‐6,10 (PA610). Physical properties of the blends are investigated using differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), dynamic mechanical thermal analysis (DMTA), impact testing, and tensile testing. Morphological features are studied using small angle X‐ray scattering (SAXS) and wide angle X‐ray scattering (WAXS). The previously unreported equilibrium enthalpy of fusion for PA410 is found to be 269 J/g. Melting point depression from DSC is used to establish miscibility and calculate the polymer–polymer interaction parameter which is approximately independent of composition and equal to −0.25 kJ/mol. Crystallization induced phase separation is observed wherein crystallization drives phase separation. SAXS exhibits an increase in lamellar long spacing with increasing PA610 content. WAXS confirms the presence of only PA410 and PA610 crystals. The mechanical properties of the blends are shown to deviate from a simple law of mixtures. This miscible biorenewable polymer blend, exhibiting crystallization induced phase separation, and characterized by superior properties is of both scientific and potential commercial interest. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43626.
Fabrication of bimodal porous PLGA scaffolds by supercritical CO2 foaming/particle leaching technique
Authors: Xin Xin , Liu Qian‐Qian , Chen Chuan‐Xin , Guan Yi‐Xin , Yao Shan‐Jing
Published: April 2016

Specific pore structure is a vital essential for scaffolds applied in tissue engineering. In this article, poly(lactide‐co‐glycolide) (PLGA) scaffolds with a bimodal pore structure including macropores and micropores to facilitate nutrient transfer and cell adhesion were fabricated by combining supercritical CO2 (scCO2) foaming with particle leaching technique. Three kinds of NaCl particles with different scales (i.e., 100–250, <75, <10 μm) were used as porogens, respectively. In particular, heterogeneous nucleation occurred to modify scCO2 foaming/particle leaching process when NaCl submicron particles (<10 μm) were used as porogens. The observation of PLGA scaffolds gave a formation of micropores (pore size <10 μm) in the cellular walls of macropores (pore size around 100–300 μm) to present a bimodal pore structure. With different mass fractions of NaCl introduced, the porosity of PLGA scaffolds ranged from 68.4 ± 1.4 to 88.7 ± 0.4% for three NaCl porogens. The results of SEM, EDS, and in vitro cytotoxicity test of PLGA scaffolds showed that they had uniform structures and were compatible for cell proliferation with no toxicity. This novel scCO2 foaming/particle leaching method was promising in tissue engineering due to its ability to fabricate scaffolds with precise pore structure and high porosity. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43644.
Enhanced adsorption and recovery of Pb(II) from aqueous solution by alkali‐treated persimmon fallen leaves
Authors: Fan Ruiyi , Yi Qingping , Xie Yucong , Xie Feng , Zhang Qinglin , Luo Zhengrong
Published: April 2016

Persimmon fallen leaves were employed to prepare a renewable and low‐cost biosorbent named as NPFL. Effects of initial pH, contact time, initial Pb(II) concentration, coexisting metal ions, and ionic strength on adsorption of Pb(II) from aqueous solution by NPFL were studied in detail. Enhanced removal capacity of NPFL toward Pb(II) was observed, and the maximum adsorption capacity was evaluated as 256 mg g−1 by Langmuir modeling calculation. The fast adsorption process and the well‐fitted kinetics data with pseudo‐second‐order model indicated that chemisorption is the main rate‐limiting step for the adsorption process. NPFL had superior adsorption selectivity for Pb(II) from aqueous solution with coexisting metal ions. Characterization of NPFL and adsorption mechanism (electrostatic attraction, ion exchange, and chelation) were performed using XRD, SEM‐EDS, FT‐IR, XPS, and TGA. The results suggested that NPFL could be utilized as a potential candidate for the preconcentration of Pb(II) recovery and its removal in practice. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43656.
The effects of residual polymerization solvent on the physical properties of poly(2‐cyano‐p‐phenylene terephthalamide)
Authors: Jung Dae Eon , Kim Dong Jun , Eom Youngho , Lee Jaeyoung , Kim Byoung Chul
Published: April 2016

Poly(2‐cyano‐p‐phenylene terephthalamide) (CY‐PPTA) was obtained by the polycondensation of terephthaloyl dichloride and 2‐cyano‐p‐phenylene diamine in the mixture of N‐methyl‐2‐pyrrolidone (NMP) and calcium chloride (CaCl2). Washing the polymerized product with water and drying at the elevated temperature inevitably left a small amount of polymerization residues which could be eliminated only by additional washing with acetone. The thermogravimetric and 1H‐/13C‐NMR analyses revealed that the residues were largely composed of NMP which existed as a complex with the polymer. The complex was broken up between 200 and 300 °C and evolved 5 wt % of gaseous products, which had an adverse effect on the physical properties of as‐spun CY‐PPTA fibers obtained by dry jet‐wet spinning. The heat treatment of the as‐spun fibers including residual NMP exhibited some porous morphology on the fiber surface due to the evolved gases. However, the existence of the residual NMP had little effect on the intrinsic viscosity and liquid crystalline phase behavior of the polymer. Both rheological and optical properties exhibited the critical concentration at 3 wt % with the clear schlieren texture of nematic liquid crystalline phase. The inclusion of residual NMP decreased dynamic viscosity and yield stress. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43672.
Immobilization of bacteriocin nisin into a poly(vinyl alcohol) polymer matrix crosslinked with nontoxic dicarboxylic acid
Authors: Hrabalikova Martina , Holcapkova Pavlina , Suly Pavol , Sedlarik Vladimir
Published: April 2016

This work is focused on novel methodology of poly(vinyl alcohol) crosslinking by non‐toxic dicarboxylic acid, glutaric acid. The cross‐linked system was used as a matrix for immobilization of bacteriocin nisin. Effect of the crosslinking degree on physico‐chemical, morphology, mechanical, and thermal properties of poly(vinyl alcohol) films were investigated by using swelling test, Fourier transform infrared spectroscopy, scanning electron microscopy, stress–strain analysis, differential scanning calorimetry, and thermogravimetry. Release profile of the nisin from the cross‐linked poly(vinyl alcohol) was studied by high performance liquid chromatography. Antibacterial activity of the prepared systems was tested by agar diffusion test and dilution and spread plate technique. Results showed suitability of glutaric acid as effective crosslinking agent of poly(vinyl alcohol) that acts synergistically with bacteriocin nisin against the tested Gram‐positive and Gram‐negative bacterial strains. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43674.
The influence of electron beam irradiation, plastic deformation, and re‐irradiation on crystallinity degree, mechanical and sclerometric properties of GUR 1050 used for arthroplasty
Authors: Barylski Adrian , Maszybrocka Joanna , Kupka Marian , Aniołek Krzysztof , Mieszczak Łukasz
Published: April 2016

The article describes the influence of an electron beam irradiation (I), plastic deformation (D), and re‐irradiation (R) on the properties of ultrahigh molecular weight polyethylene (GUR 1050). It was found that the modification through irradiation entailed a gradual increase in the degree of crystallinity (after irradiation–I). After plastic deformation and re‐irradiation (IDR) the degree of crystallinity decreases which had a direct influence on the mechanical properties. The polymer irradiation only (technique I) resulted in an increase in the maximum stress as compared with the material in the initial state. The application of deformation and re‐irradiation (technique IDR) allowed increasing the deformation resistance by more than 40%. Moreover, the irradiation with an electron beam resulted in the increase in hardness (H) and Young's modulus (E) proportionally to the applied irradiation dose and in the reduction of total indentation work (Wtot) and its components. After deformation and re‐irradiation the polyethylene hardness went down. The application of technique (I) caused an improvement to the material abrasion resistance (reduction of parameter PD–working scratch depth) with the increasing irradiation dose. The introduction of deformation and re‐irradiation did not have a material impact on parameter (PD) increasing at the same time elastic properties of UHMWPE (increase in parameter NPS–elastic recovery). Modification IDR has changed the wear mechanism (β) toward ploughing and has increased the abrasion‐resistance index (Wβ) and also significantly reduced the coefficient of friction (μ) of GUR 1050. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43683.
Deficiency of Adenosine Deaminase Type 2: A Description of Phenotype and Genotype in Fifteen Cases
Authors: Nanthapisal Sira , Murphy Claire , Omoyinmi Ebun , Hong Ying , Standing Ariane , Berg Stefan , Ekelund Maria , Jolles Stephen , Harper Lorraine , Youngstein Taryn , Gilmour Kimberly , Klein Nigel J. , Eleftheriou Despina , Brogan Paul A.
Published: April 2016

Objective

To describe the clinical features, genotype, and treatment in a series of subjects with confirmed adenosine deaminase 2 (ADA2) deficiency.

Methods

All symptomatic subjects were referred for genetic testing for suspected ADA2 deficiency; relatives of index cases were also screened. Demographic, clinical, and laboratory characteristics and treatments were recorded. Genetic analyses included whole‐exome sequencing in 4 subjects and Sanger sequencing of CECR1 (the gene for cat eye syndrome chromosome region candidate 1) in all subjects. Assays for ADA2 enzyme activity and quantitative polymerase chain reaction analysis of CECR1 messenger RNA (mRNA) were also performed.

Results

We identified 15 subjects with ADA2 deficiency, 5 of whom were asymptomatic (relatives of index cases; ages 5–42 years). Homozygous or compound heterozygous mutations in CECR1 were identified in all subjects. Phenotypic manifestations in the patients with symptomatic ADA2 deficiency included livedo racemosa (73.3%), neurologic involvement (53.3%), and immunodeficiency (46.7%). CECR1 mRNA expression in 8 subjects, including 5 who were presymptomatic, was significantly lower than in healthy controls (P = 0.0016). Subjects with ADA2 deficiency (with or without symptoms) also had lower ADA2 enzyme activity compared to healthy pediatric controls (P < 0.0001) and patients with sporadic (nonfamilial) childhood polyarteritis nodosa (PAN) without CECR1 mutation (P = 0.0108). Anti−tumor necrosis factor therapy was required in 9 of the 10 symptomatic subjects.

Conclusion

The clinical manifestations of ADA2 deficiency ranged in severity from limited cutaneous involvement to severe multisystemic vasculitis; one‐third of our cases (5 of 15) were currently asymptomatic, and required close monitoring. We recommend CECR1 screening for unaffected siblings of index cases, cases of familial vasculitis, and cases of PAN that is resistant to standard treatment.
Enhancement of Open Circuit Voltage of a ZnO‐Based Dye‐Sensitized Solar Cell by Means of Piezotronic Effect
Authors: Bettini Simona , Pagano Rosanna , Valli Ludovico , Giancane Gabriele
Published: April 2016

Two of the most known properties of ZnO were used to improve the performance of a dye‐sensitized solar cell (DSSC) using a nanoadduct formed by zinc oxide and the well‐known ruthenium dye N719. The wurtzite form of zinc oxide suffers from piezoelectricity and its energetic levels are very similar to those of the most used inorganic semiconductor employed in DSSCs, that is, TiO2. We demonstrate that the synthesis of a ZnO@N719 nanoadduct does not affect the electronic communication between the inorganic semiconductor and the organic dye. The I–V characteristics in the dark and under illumination highlight a photoactivity of the ZnO@N719 active layer with values of Jsc, Voc and fill factor comparable to the data reported in the literature. When a mechanical strain is applied to the ZnO@N719 film, a piezopotential is recorded and it depends on the intensity of the applied pressure. According to the piezotronic effect, mechanical strain contributes to increase the open circuit voltage by about 14 %.
Nickel‐Catalyzed Oxidative C−H/N−H Isocyanide Insertion: An Efficient Synthesis of Iminoisoindolinone Derivatives
Authors: Hao Wenyan , Tian Jun , Li Wu , Shi Renyi , Huang Zhiliang , Lei Aiwen
Published: April 2016

Transition metal‐catalyzed isocyanide insertion has served as a fundamental and important chemical transformation. Classical isocyanide insertion usually occurs between organohalides and nucleophiles, which normally involves tedious and non‐atom‐economical prefunctionalization processes. However, oxidative C−H/N−H isocyanide insertion offers an efficient and green alternative. Herein, a nickel‐catayzed oxidative C−H/N−H isocyanide insertion of aminoquinoline benzamides has been developed. Different kinds of iminoisoindolinone derivatives could be synthesized in good yields by utilizing Ni(acac)2 as the catalyst. In this transformation, isocyanide serves as an efficient C1 connector, which further inserted into two simple nucleophiles (C−H/N−H), representing an effective way to construct heterocycles.
Protein–Nanoparticle Interaction‐Induced Changes in Protein Structure and Aggregation
Authors: Kim Yuna , Ko Sung Min , Nam Jwa‐Min
Published: April 2016

Large surface area, small size, strong optical properties, controllable structural features, variety of bioconjugation chemistries, and biocompatibility make many different types of nanoparticles (NPs), such as gold NPs, useful for many biological applications, such as biosensing, cellular imaging, disease diagnostics, drug delivery, and therapeutics. Recently, interactions between proteins and NPs have been extensively studied to understand, control, and utilize the interactions involved in biomedical applications of NPs and several biological processes, such as protein aggregation, for many diseases, including Alzheimer's disease. These studies also offer fundamental knowledge on changes in protein structure, protein aggregation mechanisms, and ways to unravel the roles and fates of NPs within the human body. This review focuses on recent studies on the roles and uses of NPs in protein structural changes and aggregation processes.
Pre‐Incubation of Auric Acid with DNA Is Unnecessary for the Formation of DNA‐Templated Gold Nanoclusters
Authors: Chen Yang , Tao Guangyu , Lin Ruoyun , Pei Xiaojing , Liu Feng , Li Na
Published: April 2016

The rationale for the preparation of DNA‐templated gold nanoclusters (DNA‐Au NCs) has not been well understood, thereby slowing down the advancement of the synthesis and applications of DNA‐Au NCs. The interaction between metal ions and the DNA template seems to be the key factor for the successful preparation of DNA‐templated metal nanoclusters. With the help of circular dichroism in this contribution, we put efforts into interrogating the necessity of pre‐incubation of HAuCl4 with poly‐adenine template in the formation of Au NCs by citrate reduction. Our results revealed that the pre‐incubation of HAuCl4 with poly‐adenine is not favorable for the formation of Au NCs, which is distinctly different from the formation process for silver nanoclusters. It is our hope that this study can provide guidance in the preparation of Au NCs with more DNA templates.
Cascade Synthesis of Five‐Membered Lactones using Biomass‐Derived Sugars as Carbon Nucleophiles
Authors: Yamaguchi Sho , Matsuo Takeaki , Motokura Ken , Miyaji Akimitsu , Baba Toshihide
Published: April 2016

We report the cascade synthesis of five‐membered lactones from a biomass‐derived triose sugar, 1,3‐dihydroxyacetone, and various aldehydes. This achievement provides a new synthetic strategy to generate a wide range of valuable compounds from a single biomass‐derived sugar. Among several examined Lewis acid catalysts, homogeneous tin chloride catalysts exhibited the best performance to form carbon–carbon bonds. The scope and limitations of the synthesis of five‐membered lactones using aldehyde compounds are investigated. The cascade reaction led to high product selectivity as well as diastereoselectivity, and the mechanism leading to the diastereoselectivity was discussed based on isomerization experiments and density functional theory (DFT) calculations. The present results are expected to support new approaches for the efficient utilization of biomass‐derived sugars.
Dynamic Output‐Feedback Control for T‐S Fuzzy Systems with Input Time‐Varying Delay
Authors: Zhang Ziye , Lin Chong , Chen Bing
Published: April 2016

This paper considers the problem of the
control for T‐S fuzzy systems with input time‐varying delay via dynamic output feedback. Firstly, by applying the reciprocally convex approach, new delay‐dependent sufficient condition for
performance analysis is obtained. Then, a less conservative condition for the existence of the
controllers is given in terms of linear matrix inequalities (LMIs). Moreover, in the considered system, the time‐delay term is included in the measured output. This results in the difficulty in designing the controllers being increased and the obtained results being applied to a wider class of fuzzy systems than the most existing ones. The main contribution of this work lies in the application of the reciprocally convex inequality and the time‐delay term included in the measured output. Finally, the advantages and effectiveness of the present results are shown by several numerical examples.
Numerical optimal control method for shockwaves reduction at stationary bottlenecks
Authors: Strnad Irena , Kramar Fijavž Marjeta , Žura Marijan
Published: April 2016

The paper introduces an optimal control method for traffic management with variable speed limits. It consists of traffic flow dynamics prediction with a non‐linearized Lighthill–Whitham–Richards macroscopic traffic flow model, introduction of a cost functional, which enables stable shockwaves optimization, and numerical implementation of the optimization process with differential evolution. The method overcomes the discretization issues and provides speed limits that are in general not limited to small number of successive discrete points, i.e. variable message signs locations, nor in rounded speed limits. Performance of the method is demonstrated on a case study, which shows promising reduction of the backward moving shockwave that occurs because of a stationary bottleneck. Copyright © 2016 John Wiley & Sons, Ltd.
Expression of UGT1A subfamily in rat brain
Authors: Sakakibara Yukiko , Katoh Miki , Imai Kuniyuki , Kondo Yuya , Asai Yuki , Ikushiro Shin‐ichi , Nadai Masayuki
Published: April 2016

UDP‐glucuronosyltransferase (UGT) is an enzyme that catalyses a major phase II reaction in drug metabolism. Glucuronidation occurs mainly in the liver, but UGTs are also expressed in extrahepatic tissues, where they play an important role in local metabolism. UGT1A isoforms catalyse the glucuronidation of several drugs, neurotransmitters and neurosteroids that exert pharmacological and physiological effects on the brain. The aim of the current study was to determine UGT1A mRNA expression levels and glucuronidation activities in different regions of the rat brain (namely the cerebellum, frontal cortex, parietal cortex, piriform cortex, hippocampus, medulla oblongata, olfactory bulb, striatum and thalamus). It was found that all UGT1A isoforms were expressed in all the nine regions, but their expression levels differed between the regions. The difference between the regions of the brain where the mRNA levels were highest and those where they were lowest ranged between 2.1‐ to 7.8‐fold. Glucuronidation activities were measured using the UGT substrates such as mycophenolic acid, p‐nitrophenol and umbelliferone. Glucuronidation activity was detected in all nine regions of the brain. Activity levels differed between the regions, and were highest in the cerebellum, medulla oblongata and olfactory bulb. Differences in glucuronidation activity between regions with the highest rates and those with the lowest rates ranged from 5.3‐ to 10.1‐fold. These results will contribute to our current understanding of the physiological and pharmacokinetic roles of drug‐metabolizing enzymes in the brain. Copyright © 2016 John Wiley & Sons, Ltd.
Sirenomelia in Argentina: Prevalence, geographic clusters and temporal trends analysis
Authors: Groisman Boris , Liascovich Rosa , Gili Juan Antonio , Barbero Pablo , Bidondo María Paz ,   the RENAC Task Force
Published: April 2016

Background

Sirenomelia is a severe malformation of the lower body characterized by a single medial lower limb and a variable combination of visceral abnormalities. Given that Sirenomelia is a very rare birth defect, epidemiological studies are scarce. The aim of this study is to evaluate prevalence, geographic clusters and time trends of sirenomelia in Argentina, using data from the National Network of Congenital Anomalies of Argentina (RENAC) from November 2009 until December 2014.

Methods

This is a descriptive study using data from the RENAC, a hospital‐based surveillance system for newborns affected with major morphological congenital anomalies. We calculated sirenomelia prevalence throughout the period, searched for geographical clusters, and evaluated time trends.

Results

The prevalence of confirmed cases of sirenomelia throughout the period was 2.35 per 100,000 births. Cluster analysis showed no statistically significant geographical aggregates. Time‐trends analysis showed that the prevalence was higher in years 2009 to 2010.

Conclusion

The observed prevalence was higher than the observed in previous epidemiological studies in other geographic regions. We observed a likely real increase in the initial period of our study. We used strict diagnostic criteria, excluding cases that only had clinical diagnosis of sirenomelia. Therefore, real prevalence could be even higher. This study did not show any geographic clusters. Because etiology of sirenomelia has not yet been established, studies of epidemiological features of this defect may contribute to define its causes. Birth Defects Research (Part A) 106:604–611, 2016. © 2016 Wiley Periodicals, Inc.
Early exposure of rotating magnetic fields promotes central nervous regeneration in planarian Girardia sinensis
Authors: Chen Qiang , Lin Gui‐miao , Wu Nan , Tang Sheng‐wei , Zheng Zhi‐jia , Lin Marie Chia‐mi , Xu Gai‐xia , Liu Hao , Deng Yue‐yue , Zhang Xiao‐yun , Chen Si‐ping , Wang Xiao‐mei , Niu Han‐ben
Published: April 2016

Magnetic field exposure is an accepted safe and effective modality for nerve injury. However, it is clinically used only as a supplement or salvage therapy at the later stage of treatment. Here, we used a planarian Girardia sinensis decapitated model to investigate beneficial effects of early rotary non‐uniform magnetic fields (RMFs) exposure on central nervous regeneration. Our results clearly indicated that magnetic stimulation induced from early RMFs exposure significantly promoted neural regeneration of planarians. This stimulating effect is frequency and intensity dependent. Optimum effects were obtained when decapitated planarians were cultured at 20 °C, starved for 3 days before head‐cutting, and treated with 6 Hz 0.02 T RMFs. At early regeneration stage, RMFs exposure eliminated edema around the wound and facilitated subsequent formation of blastema. It also accelerated cell proliferation and recovery of neuron functionality. Early RMFs exposure up‐regulated expression of neural regeneration related proteins, EGR4 and Netrin 2, and mature nerve cell marker proteins, NSE and NPY. These results suggest that RMFs therapy produced early and significant benefit in central nervous regeneration, and should be clinically used at the early stage of neural regeneration, with appropriate optimal frequency and intensity. Bioelectromagnetics. Bioelectromagnetics. 37:244–255, 2016. © 2016 Wiley Periodicals, Inc.
Intracellular evolution of mitochondrial DNA (mtDNA) and the tragedy of the cytoplasmic commons
Authors: Haig David
Published: April 2016

Mitochondria exist in large numbers per cell. Therefore, the strength of natural selection on individual mtDNAs for their contribution to cellular fitness is weak whereas the strength of selection in favor of mtDNAs that increase their own replication without regard for cellular functions is strong. This problem has been solved for most mitochondrial genes by their transfer to the nucleus but a few critical genes remain encoded by mtDNA. Organisms manage the evolution of mtDNA to prevent mutational decay of essential services mitochondria provide to their hosts. Bottlenecks of mitochondrial numbers in female germlines increase the homogeneity of mtDNAs within cells and allow intraorganismal selection to eliminate cells with low quality mitochondria. Mechanisms of intracellular “quality control” allow direct selection on the competence of individual mtDNAs. These processes maintain the integrity of mtDNAs within the germline but are inadequate to indefinitely maintain mitochondrial function in somatic cells.
Bounds on the average causal effects in randomized trials with noncompliance by covariate adjustment
Authors: Shan Na , Xu Ping‐Feng
Published: April 2016

In randomized trials with noncompliance, causal effects cannot be identified without strong assumptions. Therefore, several authors have considered bounds on the causal effects. Applying an idea of VanderWeele (), Chiba () gave bounds on the average causal effects in randomized trials with noncompliance using the information on the randomized assignment, the treatment received and the outcome under monotonicity assumptions about covariates. But he did not consider any observed covariates. If there are some observed covariates such as age, gender, and race in a trial, we propose new bounds using the observed covariate information under some monotonicity assumptions similar to those of VanderWeele and Chiba. And we compare the three bounds in a real example.
Spectroscopic studies of bovine serum albumin adsorbed onto magnetic–thermosensitive carbon microspheres
Authors: Zhang Huan , Chen Lin , Li Longfei , Yang Yongzhen , Liu Xuguang
Published: April 2016

To investigate the influence of magnetic–thermosensitive carbon microspheres (MTCMSs) as a targeting drug carrier on serum albumins in vitro, in this study, bovine serum albumin (BSA) was chosen as a template protein to explore the interaction between serum proteins and MTCMSs. Fluorescence spectrophotometry, ultraviolet–visible absorbance (UV–vis) spectrophotometry and circular dichroism spectrometry were used to investigate the interaction between MTCMSs and BSA. Results indicate that BSA interacts with MTCMSs and the fluorescence intensity of BSA is quenched by 50% in a static quenching at 310 K when the concentration of MTCMSs reaches 30 mg/L. Thermodynamic parameters including free energy change (△Gθ), enthalpy change (△Hθ) and entropy change (△Sθ) were calculated. The results (△Gθ < 0, △Hθ < 0 and △Sθ > 0) suggest a spontaneous process and the formation of a hydrogen bond between MTCMSs and BSA. UV–vis measurements reveal that the micro‐environment of an amino acid residue is altered in the presence of MTCMSs. The α‐helix content of BSA decreases by 4% and the β‐sheet content increases by 3.2% with increasing concentrations of MTCMSs to 30 mg/L, illustrating a change in the skeletal structure of BSA. These results demonstrate that MTCMSs as a targeting drug carrier impact the structure of serum albumins. This work provides not only a theoretical basis of BSA adsorption onto MTCMSs, but also an understanding of safe drug carriers in biomedicine. Copyright © 2016 John Wiley & Sons, Ltd.
Chemiluminescence analysis of antioxidant capacity for serum albumin isolated from healthy or uremic volunteers
Authors: Huang Chih‐Yang , Liou Show‐Yih , Kuo Wei‐Wen , Wu Hsi‐Chin , Chang Yen‐Lin , Chen Tung‐Sheng
Published: April 2016

Regular hemodialysis treatment induces an elevation in oxidative stress in patients with end‐stage renal failure, resulting in oxidative damage of the most abundant serum protein, albumin. Oxidation of serum albumin causes depletion of albumin reactive thiols, leading to oxidative modification of serum albumin. The aim of this study was to screen the antioxidant capacity of albumins isolated from uremic patients (HD‐ALB) or healthy volunteers (N‐ALB). From high‐performance liquid chromatography spectra, we observed that one uremic solute binds to HD‐ALB via the formation of disulfide bonds between HD‐ALB and the uremic solute. Furthermore, we found using chemiluminescent analysis that the antioxidant capacities for N‐ALB to scavenge reactive oxygen species including singlet oxygen, hypochlorite and hydrogen peroxide were higher than HD‐ALB. Our results suggest that protein‐bound uremic solute binds to albumin via formation of disulfide bonds, resulting in the depletion of albumin reactive thiols. The depletion of albumin reactive thiols leads to a reduced antioxidant capacity of HD‐ALB, implying postmodification of albumin. This situation may reduce the antioxidant capacity of albumin and increase oxidative stress, resulting in increase in complications related to oxidative damage in uremic patients. Copyright © 2016 John Wiley & Sons, Ltd.
Review: Progresses in understanding N‐ethylmaleimide sensitive factor (NSF) mediated disassembly of SNARE complexes
Authors: Ryu Je-Kyung , Jahn Reinhard , Yoon Tae‐Young
Published: April 2016

N‐ethylmaleimide sensitive factor (NSF) is a key protein of intracellular membrane traffic. NSF is a highly conserved protein belonging to the ATPases associated with other activities (AAA+ proteins). AAA+ share common domains and all transduce ATP hydrolysis into major conformational movements that are used to carry out conformational work on client proteins. Together with its cofactor SNAP, NSF is specialized on disassembling highly stable SNARE complexes that form after each membrane fusion event. Although essential for all eukaryotic cells, however, the details of this reaction have long been enigmatic. Recently, major progress has been made in both elucidating the structure of NSF/SNARE complexes and in understanding the reaction mechanism. Advances in both cryo EM and single molecule measurements suggest that NSF, together with its cofactor SNAP, imposes a tight grip on the SNARE complex. After ATP hydrolysis and phosphate release, it then builds up mechanical tension that is ultimately used to rip apart the SNAREs in a single burst. Because the AAA domains are extremely well‐conserved, the molecular mechanism elucidated for NSF is presumably shared by many other AAA+ ATPases. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 518–531, 2016.
Invited review: Mechanisms of GTP hydrolysis and conformational transitions in the dynamin superfamily
Authors: Daumke Oliver , Praefcke Gerrit J. K.
Published: April 2016

Dynamin superfamily proteins are multidomain mechano‐chemical GTPases which are implicated in nucleotide‐dependent membrane remodeling events. A prominent feature of these proteins is their assembly‐ stimulated mechanism of GTP hydrolysis. The molecular basis for this reaction has been initially clarified for the dynamin‐related guanylate binding protein 1 (GBP1) and involves the transient dimerization of the GTPase domains in a parallel head‐to‐head fashion. A catalytic arginine finger from the phosphate binding (P‐) loop is repositioned toward the nucleotide of the same molecule to stabilize the transition state of GTP hydrolysis. Dynamin uses a related dimerization‐dependent mechanism, but instead of the catalytic arginine, a monovalent cation is involved in catalysis. Still another variation of the GTP hydrolysis mechanism has been revealed for the dynamin‐like Irga6 which bears a glycine at the corresponding position in the P‐loop. Here, we highlight conserved and divergent features of GTP hydrolysis in dynamin superfamily proteins and show how nucleotide binding and hydrolysis are converted into mechano‐chemical movements. We also describe models how the energy of GTP hydrolysis can be harnessed for diverse membrane remodeling events, such as membrane fission or fusion. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 580–593, 2016.
Urinary metabolomic study of systemic lupus erythematosus based on gas chromatography/mass spectrometry
Authors: Yan Bei , Huang Jia , Dong Fan , Yang Liping , Huang Cibo , Gao Ming , Shi Aixin , Zha Weibin , Shi Luyi , Hu Xin
Published: April 2016

Systemic lupus erythematosus (SLE) is an autoimmune disease with heterogeneous organ and system manifestations. In this study, urinary metabolic alterations related to SLE were investigated by performing gas chromatography/mass spectrometry (GC/MS) based metabolomics and multivariate statistical analysis. Patients with SLE and healthy controls could be clearly differentiated in view of the metabolic abnormity in urine. Among 70 identified endogenous metabolites, 23 metabolites were dramatically increased in SLE patients, which involved in several key metabolic pathways including energy metabolism, nucleotide metabolism, oxidative stress and gut‐microbiome‐derived metabolism. This noninvasive and GC/MS‐based metabolomic technique is a promising and potent strategy for identifying novel biomarkers and understanding pathogenesis of SLE. Copyright © 2016 John Wiley & Sons, Ltd.
Analysis of the pharmacokinetics and metabolism of aloe‐emodin following intravenous and oral administrations in rats
Authors: Yu Chung‐Ping , Shia Chi‐Sheng , Lin Hui‐Ju , Hsieh Yow‐Wen , Lin Shiuan‐Pey , Hou Yu‐Chi
Published: April 2016

Aloe‐emodin, a natural polyphenolic anthraquinone, has shown various beneficial bioactivities in vitro. The aim of this study was to investigate the pharmacokinetics and metabolism of aloe‐emodin. Aloe‐emodin was intravenously and orally administered to rats. The concentrations of aloe‐emodin and rhein, a metabolite of aloe‐emodin, were determined by HPLC method prior to and after hydrolysis with β‐glucuronidase and sulfatase/β‐glucuronidase. The results showed that the systemic exposures of aloe‐emodin and its metabolites were ranked as aloe‐emodin glucuronides (G) > rhein sulfates (S) > aloe‐emodin > rhein and rhein G when aloe‐emodin was given intravenously. In contrast, when aloe‐emodin was administered orally, the parent form of aloe‐emodin was not absorbed per se, and the systemic exposures of its metabolites were ranked as aloe‐emodin G > rhein G > rhein. In conclusion, the metabolites of aloe‐emodin are more important than the parent form for the bioactivities in vivo. Copyright © 2016 John Wiley & Sons, Ltd.