bluuebunny/crossref_metadata_2025 huggingface dataset:
Diphenyldibenzofulvene‐Based Sensitizers for Efficient Dye‐Sensitized Solar Cells: The Tuned Absorption Properties and Partially Suppressed Aggregation
Authors: Li Huiyang , Tang Runli , Hou Yingqin , Yang Yizhou , Chen Junnian , Liu Linfeng , Han Hongwei , Peng Tianyou , Li Qianqian , Li Zhen
Published: January 2014

Three new organic sensitizers (LI‐62, LI‐63, and LI‐64) were designed and synthesized, in which the diphenyldibenzofulvene (DPDBF) π‐bridge was structurally modified by introducing different groups to its phenyl rings to fine‐tune the electronic properties. Accordingly, the light‐harvesting capabilities, energy levels, and photovoltaic performances were systematically investigated. The three‐dimensional configuration of DPDBF can weaken the intermolecular interactions, and, thus, benefit the orderly arrangement of the dyes onto the TiO2 surface. In comparison to LI‐62, which contained the electron‐withdrawing CF3 group as a substituent on the DPDBF moiety, LI‐64 with the electron‐donating SMe group exhibited a higher molar extinction coefficient and IPCE value, which directly led to a higher conversion efficiency and provided some useful information for the optimization of organic dyes that have a high photovoltaic performance.
A Perylene Bisimide Organogelator for Chlorinated Solvents
Authors: Lin Xu , Hirono Misaki , Kurata Hiroki , Seki Tomohiro , Maruya Yukihiro , Nakayama Ken‐ichi , Yagai Shiki
Published: January 2014

Dye‐incorporated gel‐like materials are an attractive functional soft matter for optoelectronic applications. Chlorinated solvents are commonly used for the development of organic devices. Herein, we report that a perylene‐bisimide‐functionalized flexible bisurea can work as an efficient organogelator for several chlorinated solvents. The bisurea formed organogels in CHCl3 and 1,1,2,2‐tetrachloroethane (TCE), but it gave viscous solutions in CCl4 at millimolar concentrations. UV/vis and fluorescence spectroscopies, atomic force microscopy, and transmission electron microscopy observation of the diluted solutions revealed that the bisurea forms soluble supramolecular polymers in CCl4 whereas it exists as monomeric or at least oligomeric species in CHCl3 and TCE at micromolar concentrations. These results suggest that differences in the aggregation process could explain the gelation behavior in chlorinated solvents. By using a viscous CCl4 solution, we fabricated top contact organic field effect transistors. The devices showed n‐type semiconductivity with a mobility of 1.5×10−5 cm2 V−1 s−1.
A 2‐Iodobenzamide Catalyst for Oxidation of Alcohols at Room Temperature
Authors: Yakura Takayuki , Yamada Akihiro , Noda Narumi , Fujiwara Tomoya , Nambu Hisanori
Published: January 2014

A 2‐iodobenzamide catalyst for the oxidation of alcohols was developed. Reaction of alcohols with a catalytic amount of 2‐iodobenzamide in the presence of oxone as a co‐oxidant at room temperature gave the corresponding carbonyl compounds in excellent yields. Primary alcohols were directly converted into the corresponding carboxylic acids, whereas secondary alcohols were oxidized to ketones. A 2‐iodobenzoic acid‐type catalyst for alcohol oxidation at room temperature has not been reported before.
Aphonia due to vocal cord impairment induced by carbon monoxide poisoning
Authors: Koga Shunsuke , Sadahiro Tomohito , Ito Shoichi , Asahina Masato , Oda Shigeto
Published: January 2014

Case

We describe a case of a 22‐year‐old woman with alteration in consciousness and aphonia due to vocal cord impairment after carbon monoxide exposure. Brain magnetic resonance imaging revealed high signal intensity in bilateral globus pallidus and the pars reticulata of the substantia nigra on T2‐ and diffusion‐weighted images. Laryngeal fiberscopy showed bilateral immobilization of the vocal cords in median position during both inspiration and phonation. Although the effects of hyperbaric oxygen therapy remain ambiguous, these symptoms and magnetic resonance imaging findings subsided.

Outcome

Aphonia due to vocal cord impairment, as a presenting symptom of carbon monoxide poisoning, has not been previously reported. We considered the cause of aphonia was vocal cord abductor paralysis or dystonia of intralaryngeal muscles after the carbon monoxide exposure.

Conclusion

Even though aphonia is an unusual symptom in a patient with carbon monoxide poisoning, it must be taken into consideration.
The Direct Synthesis of Hydrogen Peroxide Using Platinum‐Promoted Gold–Palladium Catalysts
Authors: Edwards Jennifer K. , Pritchard James , Lu Li , Piccinini Marco , Shaw Greg , Carley Albert F. , Morgan David J. , Kiely Christopher J. , Hutchings Graham J.
Published: January 2014

The direct synthesis of hydrogen peroxide offers a potentially green route to the production of this important commodity chemical. Early studies showed that Pd is a suitable catalyst, but recent work indicated that the addition of Au enhances the activity and selectivity significantly. The addition of a third metal using impregnation as a facile preparation method was thus investigated. The addition of a small amount of Pt to a CeO2‐supported AuPd (weight ratio of 1:1) catalyst significantly enhanced the activity in the direct synthesis of H2O2 and decreased the non‐desired over‐hydrogenation and decomposition reactions. The addition of Pt to the AuPd nanoparticles influenced the surface composition, thus leading to the marked effects that were observed on the catalytic formation of hydrogen peroxide. In addition, an experimental approach that can help to identify the optimal nominal ternary alloy compositions for this reaction is demonstrated.
Hydrodeoxygenation of the Angelica Lactone Dimer, a Cellulose‐Based Feedstock: Simple, High‐Yield Synthesis of Branched C7–C10 Gasoline‐like Hydrocarbons
Authors: Mascal Mark , Dutta Saikat , Gandarias Inaki
Published: January 2014

Dehydration of biomass‐derived levulinic acid under solid acid catalysis and treatment of the resulting angelica lactone with catalytic K2CO3 produces the angelica lactone dimer in excellent yield. This dimer serves as a novel feedstock for hydrodeoxygenation, which proceeds under relatively mild conditions with a combination of oxophilic metal and noble metal catalysts to yield branched C7–C10 hydrocarbons in the gasoline volatility range. Considering that levulinic acid is available in >80 % conversion from raw biomass, a field‐to‐tank yield of drop‐in, cellulosic gasoline of >60 % is possible.
Copper‐Catalyzed α‐Amination of Phosphonates and Phosphine Oxides: A Direct Approach to α‐Amino Phosphonic Acids and Derivatives
Authors: McDonald Stacey L. , Wang Qiu
Published: January 2014

A direct approach to important α‐amino phosphonic acids and its derivatives has been developed by using copper‐catalyzed electrophilic amination of α‐phosphonate zincates with O‐acyl hydroxylamines. This amination provides the first example of CN bond formation which directly introduces acyclic and cyclic amines to the α‐position of phosphonates in one step. The reaction is readily promoted at room temperature with as little as 0.5 mol % of catalyst, and demonstrates high efficiency on a broad substrate scope.
Quadruple‐Resonance Magic‐Angle Spinning NMR Spectroscopy of Deuterated Solid Proteins
Authors: Akbey Ümit , Nieuwkoop Andrew J. , Wegner Sebastian , Voreck Anja , Kunert Britta , Bandara Priyanga , Engelke Frank , Nielsen Niels Chr. , Oschkinat Hartmut
Published: January 2014

1H‐detected magic‐angle spinning NMR experiments facilitate structural biology of solid proteins, which requires using deuterated proteins. However, often amide protons cannot be back‐exchanged sufficiently, because of a possible lack of solvent exposure. For such systems, using 2H excitation instead of 1H excitation can be beneficial because of the larger abundance and shorter longitudinal relaxation time, T1, of deuterium. A new structure determination approach, “quadruple‐resonance NMR spectroscopy”, is presented which relies on an efficient 2H‐excitation and 2H‐13C cross‐polarization (CP) step, combined with 1H detection. We show that by using 2H‐excited experiments better sensitivity is possible on an SH3 sample recrystallized from 30 % H2O. For a membrane protein, the ABC transporter ArtMP in native lipid bilayers, different sets of signals can be observed from different initial polarization pathways, which can be evaluated further to extract structural properties.
Collective Synthesis of Cladiellins Based on the Gold‐Catalyzed Cascade Reaction of 1,7‐Diynes
Authors: Yue Guozong , Zhang Yun , Fang Lichao , Li Chuang‐chuang , Luo Tuoping , Yang Zhen
Published: January 2014

The cladiellin family of natural products, which includes molecules with various biological activities, continues to invite new synthetic studies. A gold‐catalyzed tandem reaction of 1,7‐diynes to construct the 6‐5‐bicyclic ring systems that are present in a number of natural products was developed. This reaction was applied as the key step to realize the formal and total syntheses of nine members of the cladiellin family in an enantio‐ and diastereoselective manner. This modular and efficient approach could also be used for the construction of other cladiellins, as well as their analogues, for follow‐up studies.
Turning Regioselectivity into Stereoselectivity: Efficient Dual Resolution of P‐Stereogenic Phosphine Oxides through Bifurcation of the Reaction Pathway of a Common Intermediate
Authors: Nikitin Kirill , Rajendran Kamalraj V. , Müller‐Bunz Helge , Gilheany Declan G.
Published: January 2014

Synthetic routes that provide facile access to either enantiomeric form of a target compound are particularly valuable. The crystallization‐free dual resolution of phosphine oxides that gives highly enantioenriched materials (up to 94 % ee) in excellent yields is reported. Both enantiomeric oxides have been prepared from a single intermediate, (RP)‐alkoxyphosphonium chloride, which is formed in the course of a selective dynamic kinetic resolution using a single enantiomer of menthol as the chiral auxiliary. The origin of the dual stereoselectivity lies in bifurcation of the reaction pathway of this intermediate, which works as a stereochemical railroad switch. Under controlled conditions, Arbuzov‐type collapse of this intermediate proceeds through CO bond fission with retention of the configuration at the phosphorus center. Conversely, alkaline hydrolysis of the PO bond leads to the opposite SP enantiomer.
Iridium‐Catalyzed Intermolecular Azide–Alkyne Cycloaddition of Internal Thioalkynes under Mild Conditions
Authors: Ding Shengtao , Jia Guochen , Sun Jianwei
Published: January 2014

An iridium‐catalyzed azide–alkyne cycloaddition reaction (IrAAC) of electron‐rich internal alkynes is described. It is the first efficient intermolecular AAC of internal thioalkynes. The reaction exhibits remarkable features, such as high efficiency and regioselectivity, mild reaction conditions, easy operation, and excellent compatibility with air and a broad spectrum of organic and aqueous solvents. It complements the well‐known CuAAC and RuAAC click reactions.
Mesenchymal‐Mode Migration Assay and Antimetastatic Drug Screening with High‐Throughput Microfluidic Channel Networks
Authors: Zhang Yuanqing , Zhang Weijia , Qin Lidong
Published: January 2014

Increasing evidence shows that activated mesenchymal migration is a key process of the metastatic cascade. Cancer cells usually gain such migratory capability through an epithelial‐to‐mesenchymal transition. Herein we present a high‐throughput microfluidic device with 3120 microchambers to specifically monitor mesenchymal migration. Through imaging of the whole chip and statistical analysis, we can evaluate the two key factors of velocity and percentage related to cell migratory capacity at different cell densities in culture. We also used the device to screen antimetastatic drugs for their inhibition of mesenchymal migration and prevention of metastatic malignancy. This device will provide an excellent platform for biologists to gain a better understanding of cancer metastasis.
Quantitative Analysis of Location‐ and Sequence‐Dependent Deamination by APOBEC3G Using Real‐Time NMR Spectroscopy
Authors: Furukawa Ayako , Sugase Kenji , Morishita Ryo , Nagata Takashi , Kodaki Tsutomu , Takaori‐Kondo Akifumi , Ryo Akihide , Katahira Masato
Published: January 2014

The human antiretroviral factor APOBEC3G (A3G) deaminates the newly synthesized minus strand of the human immunodeficiency virus 1 (HIV‐1), which results in the abolition of the infectivity of virus‐infectivity‐factor (Vif)‐deficient HIV‐1 strains.1–6 A unique property of A3G is that it deaminates a CCC hot spot that is located close to the 5′ end more effectively than one that is less close to the 5′ end. However, the mechanism of this process is elusive as it includes nonspecific binding of A3G to DNA and sliding of A3G along the DNA strand. Therefore, this process cannot be analyzed by existing methods using the Michaelis–Menten theory. A new real‐time NMR method has been developed to examine the nonspecific binding and the sliding processes explicitly, and it was applied to the analysis of the deamination by A3G. As a result, the location‐dependent deamination can be explained by a difference in the catalytic rates that depend on the direction of the approach of A3G to the target cytidine. Real‐time NMR experiments also showed that A3G deaminates CCCC tandem hotspots with little redundancy, which suggests that A3G efficiently mutates many CCC hotspots that are scattered throughout the HIV‐1 genome.
Substrate‐Directed Hydroacylation: Rhodium‐Catalyzed Coupling of Vinylphenols and Nonchelating Aldehydes
Authors: Murphy Stephen K. , Bruch Achim , Dong Vy M.
Published: January 2014

We report a protocol for the hydroacylation of vinylphenols with aryl, alkenyl, and alkyl aldehydes to form branched products with high selectivity. This cross‐coupling yields α‐aryl ketones that can be cyclized to benzofurans, and it enables access to eupomatenoid natural products in four steps or less from eugenol. Excellent reactivity and high levels of regioselectivity for the formation of the branched products were observed. We propose that aldehyde decarbonylation is avoided by the use of an anionic directing group on the alkene and a diphosphine ligand with a small bite angle.
A Core‐Expanded Subphthalocyanine Analogue with a Significantly Distorted Conjugated Surface and Unprecedented Properties
Authors: Shimizu Soji , Nakano Shota , Kojima Ayaka , Kobayashi Nagao
Published: January 2014

The introduction of a seven‐membered‐ring unit in the place of a five‐membered‐ring unit in the structure of subphthalocyanine resulted in significant distortion of the bowl‐shaped structure of the conjugated molecule as well as the following unprecedented properties: the preferential formation of the axially fluoro substituted species, the fluttering‐dynamic‐motion‐induced rapid exchange of P and M enantiomers, markedly split Q‐band absorption, and a clear difference in the ring‐current effects arising from the convex and concave surfaces.
Vibrational Spectroscopy of the Dehydrogenated Uracil Radical by Autodetachment of Dipole‐Bound Excited States of Cold Anions
Authors: Liu Hong‐Tao , Ning Chuan‐Gang , Huang Dao‐Ling , Wang Lai‐Sheng
Published: January 2014

Molecules with large enough dipole moments can bind an electron by the dipole field, which has little effect on the molecular core. A molecular anion can be excited to a dipole‐bound state, which can autodetach by vibronic coupling. Autodetachment spectroscopy of a complex anion cooled in a cryogenic ion trap is reported. Vibrational spectroscopy of the dehydrogenated uracil radical is obtained by a dipole‐bound state with partial rotational resolution. Fundamental frequencies for 21 vibrational modes of the uracil radical are reported. The electron affinity of the uracil radical is measured accurately to be 3.4810±0.0006 eV and the binding energy of the dipole‐bound state is measured to be 146±5 cm−1. The rotational temperature of the trapped uracil anion is evaluated to be 35 K.
A 1D/2D Helical CdS/ZnIn2S4 Nano‐Heterostructure
Authors: Xu Biao , He Peilei , Liu Huiling , Wang Pengpeng , Zhou Gang , Wang Xun
Published: January 2014

Multidimensional nano‐heterostructures (NHSs) that have unique dimensionality‐dependent integrative and synergic effects are intriguing but still underdeveloped. Here, we report the first helical 1D/2D epitaxial NHS between CdS and ZnIn2S4. Experimental and theoretical studies reveal that the mismatches in lattice and dangling bonds between 1D and 2D units govern the growth procedure. The resulting well‐defined interface induces the delocalized interface states, thus facilitate the charge transfer and enhance the performance in the photoelectrochemical cells. We foresee that the mechanistic insights gained and the electronic structures revealed would inspire the design of more complex 1D/2D NHSs with outstanding functionalities.
Stereospecific Nickel‐Catalyzed Cross‐Coupling Reactions of Alkyl Grignard Reagents and Identification of Selective Anti‐Breast‐Cancer Agents
Authors: Yonova Ivelina M. , Johnson A. George , Osborne Charlotte A. , Moore Curtis E. , Morrissette Naomi S. , Jarvo Elizabeth R.
Published: January 2014

Alkyl Grignard reagents that contain β‐hydrogen atoms were used in a stereospecific nickel‐catalyzed cross‐coupling reaction to form C(sp3)C(sp3) bonds. Aryl Grignard reagents were also utilized to synthesize 1,1‐diarylalkanes. Several compounds synthesized by this method exhibited selective inhibition of proliferation of MCF‐7 breast cancer cells.
Highly Efficient Electrocatalysts for Oxygen Reduction Based on 2D Covalent Organic Polymers Complexed with Non‐precious Metals
Authors: Xiang Zhonghua , Xue Yuhua , Cao Dapeng , Huang Ling , Chen Jian‐Feng , Dai Liming
Published: January 2014

A class of 2D covalent organic polymers (COPs) incorporating a metal (such as Fe, Co, Mn) with precisely controlled locations of nitrogen heteroatoms and holes were synthesized from various N‐containing metal–organic complexes (for example, metal–porphyrin complexes) by a nickel‐catalyzed Yamamoto reaction. Subsequent carbonization of the metal‐incorporated COPs led to the formation of COP‐derived graphene analogues, which acted as efficient electrocatalysts for oxygen reduction in both alkaline and acid media with a good stability and free from any methanol‐crossover/CO‐poisoning effects.
Poly(HEMA)/cyclodextrin‐based hydrogels for subconjunctival delivery of cyclosporin A
Authors: Başbağ A. Berna , Gümüşderelioğlu Menemşe , Şimşek Murat , Güner Ali
Published: January 2014

To enhance the solubility and ocular permeability of immunosuppressive agent, cyclosporine A (CsA), three types of delivery systems were prepared using (2‐hydroxypropyl)‐β‐cyclodextrin (HPβCD), and 2‐hydroxyethyl methacrylate (HEMA). Those systems are (i) hydrogels of HPβCD with crosslinking agent ethylene glycol diglycidylether, (ii) poly(HEMA) hydrogels, and (iii) different amounts of HPβCD‐containing poly(HEMA) hydrogels indicated as poly(HEMA‐co‐HPβCD). In the presence of HEMA, hydrogels have desired mechanical integrity with lower equilibrium content than that of hydrogels without HEMA. CsA was loaded into the HPβCD‐based hydrogels by embedding from its aqueous suspensions in higher amounts than that of the poly(HEMA) hydrogels that were loaded by CsA–HPβCD complex solution. Although the poly(HEMA) hydrogels are releasing total CsA in 3 days, long‐term release was realized from HPβCD‐based hydrogels. For subconjunctival administration, regarding to the amounts of loaded CsA, release profiles, and mechanical integrity, the most suitable system is poly(HEMA‐co‐HPβCD) hydrogels in high HPβCD content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40397.
Thermotropic systems with fixed domains exhibiting enhanced overheating protection performance
Authors: Weber Andreas , Resch Katharina
Published: January 2014

Within this study, a time saving photo‐initiated miniemulsion polymerization process (duration of polymerization was 15 min) was established in order to encapsulate a paraffin wax with an acrylate polymer shell. The obtained freeze‐dried latex was an off‐white powder exhibiting spherical particles with mean diameters around 400 nm and a concentration of paraffin wax around 56%. Mixing the reaction product with a UV‐curable resin matrix resulted in thermotropic overheating protection glazings with high light‐shielding efficiency. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 40417.
Cellulose nanofibers prepared from TEMPO‐oxidation of kraft pulp and its flocculation effect on kaolin clay
Authors: Jin Liqiang , Wei Yanwei , Xu Qinghua , Yao Wenrun , Cheng Zhengliang
Published: January 2014

Cellulose nanofibers were prepared using TEMPO/NaBr/NaClO oxidation of kraft pulp and successive ultrasonic treatment, and the properties were characterized by conductimetric titration, X‐ray diffraction, and atomic force microscopy. The resulting product was then applied as an anionic microparticle to constitute a microparticulate system with cationic polyacrylamide (CPAM), to induce the flocculation of the kaolin clay suspension. The flocculation effect was evaluated by determining the relative turbidity of clay suspension. The results showed that the obtained cellulose nanofibers had cellulose I structure with higher crystallinity than that of the kraft pulp, and their cross‐sectional dimension was in the range of 3–5 nm. They had more negative zeta potential at neutral and alkaline conditions. It was found that the microparticulate system showed high flocculation effect on kaolin clay at a very low level of nanofiber addition, and a high shear level after CPAM addition was helpful for the flocculation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40450.
BIOTYPE EXPRESSION AND INSECTICIDE RESPONSE OF Bemisia tabaci CHEMOSENSORY PROTEIN‐1
Authors: Liu Guo Xia , Xuan Ning , Chu Dong , Xie Hong Yan , Fan Zhong Xue , Bi Yu Ping , Picimbon Jean‐François , Qin Yu Chuan , Zhong Su Ting , Fa Li Yao , Gao Zhan Lin , Pan Wen Liang , Wang Guo Ying , Rajashekar Balaji
Published: January 2014

Chemosensory proteins (CSPs) are a group of small soluble proteins found so far exclusively in arthropod species. These proteins act in chemical communication and perception. In this study, a gene encoding the Type 1 CSP (BtabCSP1) from the agricultural pest Bemisia tabaci (whitefly) was analyzed to understand sequence variation and expression specificity in different biotypes. Sequence analysis of BtabCSP1 showed significant differences between the two genetically characterized biotypes, B and Q. The B‐biotype had a larger number of BtabCSP1 mutations than the Q‐biotype. Similar to most other CSPs, BtabCSP1 was more expressed in the head than in the rest of the body. One‐step RT‐PCR and qPCR analysis on total messenger RNA showed that biotype‐Q had higher BtabCSP1 expression levels than biotype‐B. Females from a mixed field‐population had high levels of BtabCSP1 expression. The interaction of BtabCSP1 with the insecticide thiamethoxam was investigated by analyzing the BtabCSP1 expression levels following exposure to the neonicotinoid, thiamethoxam, in a time/dose‐response study. Insecticide exposure increased BtabCSP1 expression (up to tenfold) at 4 and 24 h following 50 or 100 g/ml treatments.
Extracting evolutionary communities in community question answering
Authors: Zhang Zhongfeng , Li Qiudan , Zeng Daniel , Gao Heng
Published: January 2014

With the rapid growth of Web 2.0, community question answering (CQA) has become a prevalent information seeking channel, in which users form interactive communities by posting questions and providing answers. Communities may evolve over time, because of changes in users' interests, activities, and new users joining the network. To better understand user interactions inCQAcommunities, it is necessary to analyze the community structures and track community evolution over time. Existing work inCQAfocuses on question searching or content quality detection, and the important problems of community extraction and evolutionary pattern detection have not been studied. In this article, we propose a probabilistic community model (PCM) to extract overlapping community structures and capture their evolution patterns inCQA. The empirical results show that our algorithm appears to improve the community extraction quality. We show empirically, using the iPhone data set, that interesting community evolution patterns can be discovered, with each evolution pattern reflecting the variation of users' interests over time. Our analysis suggests that individual users could benefit to gain comprehensive information from tracking the transition of products. We also show that the communities provide a decision‐making basis for business.
Thieno[3,4‐c]pyrrole‐4,6‐dione‐Based Small Molecules for Highly Efficient Solution‐Processed Organic Solar Cells
Authors: Ha Jong‐jin , Kim Yu Jin , Park Jong‐gwang , An Tae Kyu , Kwon Soon‐Ki , Park Chan Eon , Kim Yun‐Hi
Published: January 2014

Two small molecules named BT‐TPD and TBDT‐TTPD with a thieno[3,4‐c]pyrrole‐4,6‐dione (TPD) unit were designed and synthesized for solution‐processed bulk‐heterojunction solar cells. Their thermal, electrochemical, optical, charge‐transport, and photovoltaic characteristics were investigated. These compounds exhibit strong absorption at 460–560 nm and low highest occupied molecular orbital levels (−5.36 eV). Field‐effect hole mobilities of these compounds are 1.7–7.7×10−3 cm2 V−1 s−1. Small‐molecule organic solar cells based on blends of these donor molecules and a acceptor display power conversion efficiencies as high as 4.62 % under the illumination of AM 1.5G, 100 mW cm−2.
Synthetic biology of avermectin for production improvement and structure diversification
Authors: Zhuo Ying , Zhang Tao , Wang Qi , Cruz‐Morales Pablo , Zhang Buchang , Liu Mei , Barona‐Gómez Francisco , Zhang Lixin
Published: January 2014

Natural products are still key sources of current clinical drugs and innovative therapeutic agents. Since wild‐type microorganisms only produce natural products in very small quantities, yields of production strains need to be improved by breaking down the precise genetic and biochemical circuitry. Herein, we use avermectins as an example of production improvement and chemical structure diversification by synthetic biology. Avermectins are macrocyclic lactones produced by Streptomyces avermitilis and are well known and widely used for antiparasitic therapy. Given the importance of this molecule and its derivatives, many efforts and strategies were employed to improve avermectin production and generate new active analogues. This review describes the current status of synthetic strategies successfully applied for developing natural‐product‐producing strains and discusses future prospects for the application of enhanced avermectin production.
The human anti‐HIV antibodies 2F5, 2G12, and PG9 differ in their susceptibility to proteolytic degradation: Down‐regulation of endogenous serine and cysteine proteinase activities could improve antibody production in plant‐based expression platforms
Authors: Niemer Melanie , Mehofer Ulrich , Torres Acosta Juan Antonio , Verdianz Maria , Henkel Theresa , Loos Andreas , Strasser Richard , Maresch Daniel , Rademacher Thomas , Steinkellner Herta , Mach Lukas
Published: January 2014

The tobacco‐related speciesNicotiana benthamianahas recently emerged as a promising host for the manufacturing of protein therapeutics. However, the production of recombinant proteins inN. benthamianais frequently hampered by undesired proteolysis. Here, we show that the expression of the human anti‐HIV antibodies 2F5, 2G12, and PG9 inN. benthamianaleaves leads to the accumulation of discrete heavy chain‐derived degradation products of 30–40 kDa. Incubation of purified 2F5 withN. benthamianaintercellular fluid resulted in rapid conversion into the 40‐kDa fragment, whereas 2G12 proved largely resistant to degradation. Such a differential susceptibility to proteolytic attack was also observed when these two antibodies were exposed to various types of proteinases in vitro. While serine and cysteine proteinases are both capable of generating the 40‐kDa 2F5 fragment, the 30‐kDa polypeptide is most readily obtained by treatment with the latter class of enzymes. The principal cleavage sites reside within the antigen‐binding domain, the VH–CH1 linker segment and the hinge region of the antibodies. Collectively, these results indicate that down‐regulation of endogenous serine and cysteine proteinase activities could be used to improve the performance of plant‐based expression platforms destined for the production of biopharmaceuticals.
Designing randomized clinical trials in surgery
Authors: Lombardi R
Published: January 2014

Not as easy as you think
Introducing basic molecular biology to Turkish rural and urban primary school children via hands‐on PCR and gel electrophoresis activities
Authors: Selli Cigdem , Yıldırım Gokce , Kaymak Aysegul , Karacicek Bilge , Ogut Deniz , Gungor Turkan , Erem Erdem , Ege Mehmet , Bümen Nilay , Tosun Metiner
Published: January 2014

This study includes the results of a 2‐day education project titled “Molecular Biology Laboratory Summer School, MoBiLYO.” The project was held at a University Research Center by scientists from Department of Pharmacology and graduate students. The project was composed of introductory lectures, model construction, DNA isolation, polymerase chain reaction (PCR), and gel electrophoresis. The participants were 13‐year‐old eighth‐graders attending primary schools affiliated with Ministry of National Education in urban and rural areas of Izmir, Turkey. The purpose of this study was to introduce basic molecular biology concepts through individually performed experiments such as PCR and gel electrophoresis integrated with creative drama. The students were assessed at the beginning and the end of each project day via mini‐tests, experimental and presentation skills evaluation forms. Data showed that students' knowledge about DNA structure and basic molecular biology techniques significantly increased. On the basis of experimental and presentational skills, there was no significant difference between kids from urban and rural schools or between public and boarding public schools, whereas the average score of girls was significantly higher than that of boys. In conclusion, individually performed experiments integrated with creative drama significantly increased students' perception of complex experimental procedures on basic molecular biology concepts. Data suggests that integration of these concepts into the science and technology curriculum of Turkish primary education may support the recruitment of future scientists who can handle rapidly developing genomic techniques that will affect our everyday life. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(2):114–120, 2014
Bacterial production of the fungus‐derived cholesterol‐lowering agent mevinolin
Authors: Bose Utpal , Hodson Mark P. , Shaw P. Nicholas , Fuerst John A. , Hewavitharana Amitha K.
Published: January 2014

Forty‐five strains from two different species (Salinispora arenicola and Salinispora pacifica) were isolated from three different marine sponge species in the Great Barrier Reef region of Australia. We found that two of the strains of Salinispora arenicola (MV0335 and MV0029) produced mevinolin, a fungus‐derived cholesterol‐lowering agent. Compound structure was determined using an integrated approach: (a) high performance liquid chromatography‐quadrupole time‐of‐flight‐mass spectrometric analysis with multimode ionization (electrospray ionization and atmospheric pressure chemical ionization) and fast polarity switching; and (b) database searching and matching of monoisotopic masses, retention times and mass spectra of the precursor and product ions of the compounds of interest and the authentic reference standards thereof. Copyright © 2014 John Wiley & Sons, Ltd.
Identification of Pyrroloformamide as a Cytokinesis Modulator
Authors: Abreu Paula A. , Sousa Thiciana S. , Jimenez Paula C. , Wilke Diego V. , Rocha Danilo D. , Freitas Hozana P. S. , Pessoa Otília D. L. , La Clair James J. , Costa‐Lotufo Letícia V.
Published: January 2014

Discovered in the late 1940s, the pyrrolinonodithioles represent a family of potent disulfide‐containing natural products. Although they are understood in a synthetic and biosynthetic context, the biological role of these materials remains unresolved. To date, their activity has been suggested to arise through regulating RNA metabolism, and more recently they have been suggested to function as backup thiols for detoxification. Using materials identified through a natural products program, we now identify the biological function of one member of this family, pyrroloformamide, as an antimitotic agent acting, in part, by disrupting cytokinesis.
Adipose‐derived stromal cells grown on a hydroxyapatite scaffold can support hematopoiesis in regenerated bone marrow in vivo
Authors: Ueda Takahiro , Fujita Atsushi , Ogawa Rei , Itoh Yasuhiko , Fukunaga Yoshitaka , Shimada Takashi , Migita Makoto
Published: January 2014

Osteoblastic cells are a key component of the bone marrow (BM) stem cell niche and help regulate hematopoietic stem cells (HSCs). We have previously demonstrated that adipose‐derived stromal cells (ADSCs) can differentiate into both osteogenic and chondrogenic cells in vitro. The current study examined whether the anatomical architecture of the BM could be regenerated in vivo by using ADSCs cultured on a hydroxyapatite (HA) scaffold. ADSCs from GFP transgenic mice were cultured in vitro on an HA scaffold. The scaffold with the attached cells was implanted subcutaneously onto the backs of C57/BL6 (Ly5.2) recipient mice. Lineage‐negative (Lin‐) Ly5.1 BM cells transduced with a lentiviral vector containing the luciferase (Luc) gene were intravenously administered to the recipient mice after lethal irradiation. Eight weeks after BM transplantation, the scaffolds were removed from the first recipient mice and subcutaneously implanted into lethally irradiated second recipient mice. The biodistribution and kinetics of Luc+ Ly5.1 cells were monitored by bioluminescence imaging and flow cytometry. Luc+ hematopoietic cells were present in the scaffolds of the secondary implanted mice for at least 8 months. Subcutaneous injection of G‐CSF resulted in wide distribution of bioluminescence signals from the original scaffolds to the whole body. Therefore, BM regenerated using ADSCs grown on an HA scaffold can support HSC populations in vivo, suggesting that a functional BM niche is reconstituted. These results may have a significant impact on the development of therapeutic strategies for various hematopoietic diseases.
Size and Shape‐controlled Pd Nanocrystals on ZnO and SiO2: When the Nature of the Support Determines the Active Phase
Authors: Crespo‐Quesada Micaela , Yoon Songhak , Jin Mingshang , Xia Younan , Weidenkaff Anke , Kiwi‐Minsker Lioubov
Published: January 2014

The structure sensitivity of acetylene hydrogenation was studied over size‐controlled cubic and octahedral Pd nanocrystals (NCs) supported on ZnO and SiO2. Acetylene hydrogenation was found to be structure sensitive [with Pd(1 1 1) in octahedra being more active than Pd(1 0 0) in cubes]. However, the response was found to vary depending on the redox properties of the support. The catalytically active and selective palladium carbide (PdCx) phase was readily formed on the SiO2‐supported Pd NCs (much faster on cubes than on octahedra), whereas a markedly less active PdZn phase was preferentially formed on the ZnO‐supported Pd nanocrystals. Here we show that the structure sensitivity of a chemical reaction is a complex phenomenon that originates from the reconstruction of the active phase in response to the reactive environment, which is ultimately determined by the support used.
Polycatenation‐Driven Self‐Assembly of Nanoporous Frameworks Based on a 1D Ribbon of Rings: Regular Structural Evolution, Interpenetration Transformation, and Photochemical Modification
Authors: Sun Jian‐Ke , Tan Bin , Cai Li‐Xuan , Chen Rui‐Ping , Zhang Jian , Zhang Jie
Published: January 2014

A series of nanoporous frameworks constructed by a polycatenated isoreticular 1D ribbon of rings have been developed. The orientation of catenated ribbons can be fine tuned by varying counter anions, which allows both pore size and shape to be systematically adjusted in a pre‐synthetic process. Distinct from conventional pore construction modes in which the organic linkers are alternately connected by metal nodes into a 3D periodic arrangement, the present polycatenation approach represents an alternative for constructing soft porous materials with tunable pore metrics and functions. Furthermore, these porous structures can interconvert into each other based on an anion‐exchange process, accompanied by the transformation of the interpenetrating structures in different dimensional networks, which is unusual in porous frameworks. In addition, such a porous framework can be post‐synthetically modified by a photoinduced [2+2] cycloaddition reaction, which not only achieves the surface modification (from conjugated to non‐conjugated inner surface), but also triggers the structural transformation from low dimension to high dimension. Such a post‐modification process reinforces the pore architecture through a covalent locking effect and has a great impact on the adsorption properties.
Iron 10‐Thiacorroles: Bioinspired Iron(III) Complexes with an Intermediate Spin (S=3/2) Ground State
Authors: Sakow Dimitri , Baabe Dirk , Böker Birte , Burghaus Olaf , Funk Markus , Kleeberg Christian , Menzel Dirk , Pietzonka Clemens , Bröring Martin
Published: January 2014

A first systematic study upon the preparation and exploration of a series of iron 10‐thiacorroles with simple halogenido (F, Cl, Br, I), pseudo‐halogenido (N3, I3) and solvent‐derived axial ligands (DMSO, pyridine) is reported. The compounds were prepared from the free‐base octaethyl‐10‐thiacorrole by iron insertion and subsequent ligand‐exchange reactions. The small N4 cavity of the ring‐contracted porphyrinoid results in an intermediate spin (i.s., S=3/2) state as the ground state for the iron(III) ion. In most of the investigated cases, the i.s. state is found unperturbed and independent of temperature, as determined by a combination of X‐ray crystallography and magnetometry with 1H NMR‐, EPR‐, and Mössbauer spectroscopy. Two exceptions were found. The fluorido iron(III) complex is inhomogenous in the solid and contains a thermal i.s. (S=3/2)→high spin (h.s., S=5/2) crossover fraction. On the other side, the cationic bis(pyridine) complex resides in the expected low spin (l.s., S=1/2) state. Chemically, the iron 10‐thiacorroles differ from the iron porphyrins mainly by weaker axial ligand binding and by a cathodic shift of the redox potentials. These features make the 10‐thiacorroles interesting ligands for future research on biomimetic catalysts and model systems for unusual heme protein active sites.
Light‐Regulated Tetracycline Binding to the Tet Repressor
Authors: Moon Jayoung , Gam Jongsik , Lee Seung‐Goo , Suh Young‐Ger , Lee Jeeyeon
Published: January 2014

Elucidation of the signal‐transmission pathways between distant sites within proteins is of great importance in medical and bioengineering sciences. The use of optical methods to redesign protein functions is emerging as a general approach for the control of biological systems with high spatiotemporal precision. Here we report the detailed thermodynamic and kinetic characterization of novel chimeric light‐regulated Tet repressor (TetR) switches in which light modulates the TetR function. Light absorbed by flavin mononucleotide (FMN) generates a signal that is transmitted to As‐LOV and YtvA‐LOV fused TetR proteins (LOV=light–oxygen–voltage), in which it alters the binding to tetracycline, the TetR ligand. The engineering of light‐sensing protein modules with TetR is a valuable tool that deepens our understanding of the mechanism of signal transmission within proteins. In addition, the light‐regulated changes of drug binding that we describe here suggest that engineered light‐sensitive proteins may be used for the development of novel therapeutic strategies.
Synthesis and Characterization of Highly Reactive and Thermostable Anatase Titania Nanoparticles for Photocatalytic Applications
Authors: Qi Fei , Moiseev Anna , Deubener Joachim , Weber Alfred P.
Published: January 2014

In der vorliegenden Arbeit wurden Anatas (TiO2)‐Nanopartikeln in einer Vormischflamme hergestellt und durch die verzögerte Zugabe eines Si‐Precursors so passiviert, dass die TiO2/SiO2‐Nanopartikeln bis zu 1050 °C weder Phasenumwandlung noch Koaleszenz zeigten. Die temperaturstabilen TiO2‐Nanopartikeln wurden erfolgreich in photokatalytischen Beschichtungen zum Beispiel für selbstreinigende Oberflächen eingesetzt, was sich in einem Ein‐Schritt‐Verfahren realisieren ließ. Zudem konnte eine photokatalytisch speziell aktive Größenklasse mit Durchmessern zwischen 10 und 15 nm identifiziert werden.
Oxidative Status, Inflammation, and Postoperative Atrial Fibrillation With Metoprolol vs Carvedilol or Carvedilol Plus N‐Acetyl Cysteine Treatment
Authors: Ozaydin Mehmet , Peker Oktay , Erdogan Dogan , Akcay Selahaddin , Yucel Habil , Icli Atilla , Ceyhan Betul M. , Sutcu Recep , Uysal Bayram A. , Varol Ercan , Dogan Abdullah , Okutan Huseyin
Published: January 2014

Background

Atrial fibrillation is associated with inflammation and oxidative stress.

Hypothesis

Carvedilol and N‐acetyl cysteine (NAC) combination decreases inflammation, oxidative stress, and postoperative atrial fibrillation (POAF) rates more than metoprolol or carvedilol.

Methods

Preoperative and postoperative total oxidative stress (TOS), total antioxidant capacity (TAC), and white blood cells (WBC) were measured in metoprolol, carvedilol, or carvedilol plus NAC groups, and association with POAF was evaluated.

Results

Preoperative TAC, TOS, and WBC levels were similar among the groups. Postoperative TAC levels were lower in the metoprolol group compared with the carvedilol group (1.0 vs 1.4) or the carvedilol plus NAC group (1.0 vs 1.9) and were also lower in the carvedilol group compared with the carvedilol plus NAC group (all P < 0.0001). Postoperative TOS levels were higher in the metoprolol group as compared with the carvedilol (29.6 vs 24.2; P < 0.0001) or the carvedilol plus NAC groups (P < 0.0001), and were also higher in the carvedilol group as compared with the carvedilol plus NAC group (24.2 vs 19.3; P < 0.0001). Postoperative WBC counts were lower in the carvedilol plus NAC group compared with the metoprolol group (12.9 vs 14.8; P = 0.004), were similar between the carvedilol and the metoprolol groups (13 vs 14.8) and between the carvedilol plus NAC group and the carvedilol group (both P > 0.05). Postoperative TAC, TOS, and WBC were associated with POAF.

Conclusions

Carvedilol plus NAC reduced oxidative stress and inflammation compared with metoprolol and decreased oxidative stress compared with carvedilol. Postoperative TAC, TOS, and WBC were associated with POAF.
Regional Variation Across the United States in Management and Outcomes of ST‐Elevation Myocardial Infarction: Analysis of the 2003 to 2010 Nationwide Inpatient Sample Database
Authors: Kolte Dhaval , Khera Sahil , Aronow Wilbert S. , Mujib Marjan , Palaniswamy Chandrasekar , Ahmed Ali , Frishman William H. , Fonarow Gregg C.
Published: January 2014

Background

Regional differences in the treatment and outcomes of patients with ST‐elevation myocardial infarction (STEMI) within the United States remain poorly understood.

Hypothesis

Treatment choice and outcomes in patients with STEMI differ between regions within the United States.

Methods

We used the 2003 to 2010 Nationwide Inpatient Sample databases to identify all patients age ≥40 years hospitalized with STEMI. Patients were divided into 4 groups according to region: Northeast, Midwest, South, and West. Multivariable logistic regression was used to identify differences in treatment choice and outcomes (in‐hospital mortality, acute stroke, and cardiogenic shock) among the 4 regions.

Results

Of 1 990 486 patients age ≥40 years with STEMI, 350 073 (17.6%) were hospitalized in the Northeast, 483 323 (24.3%) in the Midwest, 784 869 (39.4%) in the South, and 372 222 (18.7%) in the West. Compared with the Northeast, patients in the Midwest, South, and West were less likely to receive medical therapy alone and more likely to receive percutaneous coronary intervention and coronary artery bypass grafting. Risk‐adjusted in‐hospital mortality was higher in the Midwest (odds ratio [OR]: 1.07, 95% confidence interval [CI]: 1.05‐1.09, P <0.001), South (OR: 1.03, 95% CI: 1.01‐1.05, P = 0.001), and West (OR: 1.06, 95% CI: 1.04‐1.08, P <0.001), as compared with the Northeast. When adjusted further for regional variation in treatment selection, risk‐adjusted in‐hospital mortality was even higher in the Midwest, West, and South.

Conclusions

Despite higher reperfusion and revascularization rates, STEMI patients in the Midwest, West, and South have paradoxically higher risk‐adjusted in‐hospital mortality as compared with patients in the Northeast.
Evaluation of plasma Epstein‐Barr virus DNA load to distinguish nasopharyngeal carcinoma patients from healthy high‐risk populations in Southern China
Authors: Ji Ming‐Fang , Huang Qi‐Hong , Yu Xia , Liu Zhiwei , Li Xinghua , Zhang Li‐Fang , Wang Panpan , Xie Shang‐Hang , Rao Hui‐Lan , Fang Fang , Guo Xiang , Liu Qing , Hong Ming‐Huang , Ye Weimin , Zeng Yi‐Xin , Cao Su‐Mei
Published: January 2014

BACKGROUND

The utility of circulating Epstein‐Barr Virus (EBV) DNA as a tumor marker for nasopharyngeal carcinoma (NPC) detection suggests that it might improve the diagnostic performance of anti‐EBV antibody markers in NPC screening. In this study, the authors evaluated whether circulating EBV DNA load is capable of distinguishing NPC patients from high‐risk individuals who have positive anti‐EBV antibodies.

METHODS

In a population‐based NPC screening trial in Sihui City and Zhongshan City, Guangdong Province, China, the authors previously identified 862 high‐risk participants with 2 screening markers, immunoglobulin A (IgA) antibodies to EBV capsid antigen (VCA/IgA) and nuclear antigen‐1 (EBNA1/IgA). In the current study, real‐time polymerase chain reaction was used to measure the baseline plasma EBV DNA load among 825 participants (97%). Follow‐up was extended to the end of 2011 to evaluate the diagnostic and predictive values of plasma EBV DNA load.

RESULTS

By using 0 copies/mL as the cutoff value, plasma EBV DNA had a sensitivity of 86.8% (33 of 38 patients) for NPC detected within the first year of follow‐up, yielding a positive predictive value of 30% (33 of 110 participants) and a negative predictive value of 99.3% (696 of 701 participants). The patients who had early stage NPC had lower sensitivity (81.5%; 22 of 27 patients) than those who had advanced NPC (100%; 11 of 11 patients). For the 14 patients who had NPC detected after 1 year of follow‐up, only 50% (7 of 14 patients) tested positive for EBV DNA at baseline.

CONCLUSIONS

The plasma EBV DNA load may improve the accuracy of diagnosing NPC in high‐risk individuals, but it appears to have limited value in screening patients who have early stage NPC and predicting NPC development. Cancer 2014;120:1353–1360. © 2014 American Cancer Society.