bluuebunny/crossref_metadata_2025 huggingface dataset:
Palladium‐Catalyzed Cascade sp2 C−H Functionalization/Intramolecular Asymmetric Allylation: From Aryl Ureas and 1,3‐Dienes to Chiral Indolines
Authors: Chen Shu‐Sen , Wu Min‐Song , Han Zhi‐Yong
Published: May 2017

A chiral PdII‐catalyzed cascade sp2 C−H functionalization/intramolecular asymmetric allylation reaction is reported. A new chiral sulfoxide–oxazoline (SOX) ligand bearing single chiral center on the sulfur was identified as the optimal ligand for the reaction, being efficient both in the C−H cleavage step and the stereocontrol of the allylation step. The broad scope of this method with respect to aryl ureas and 1,3‐dienes enables the rapid construction of valuable chiral indoline derivatives with high yields and enantioselectivities (up to 99 % yield, up to 95:5 e.r.).
Total Synthesis of Aplydactone by a Conformationally Controlled C−H Functionalization
Authors: Liu Chenguang , Chen Renzhi , Shen Yang , Liang Zhanhao , Hua Yuhui , Zhang Yandong
Published: May 2017

A concise, protecting‐group‐free total synthesis of the unusual brominated sesquiterpene aplydactone is described. Our synthesis features a [2+2] photocycloaddition, a Wolff ring contraction, an unusual remote C−H functionalization to establish the highly strained tetracyclic core, and a hydrogen‐atom transfer (HAT) reaction to access the bromine‐containing stereocenter. A finely tuned conformation of the α‐diazoketone precursor is the key for the success of the late‐stage transannular C−H insertion to deliver a bridged six‐membered ring and a quaternary stereocenter (C6) between two quaternary carbon atoms (C1 and C7).
Total Synthesis of (±)‐Corymine
Authors: Zhang Benxiang , Wang Xiaoqing , Cheng Chao , Sun Deqian , Li Chaozhong
Published: May 2017

The first total synthesis of the hexacyclic indole alkaloid (±)‐corymine is described. Starting from the readily available N‐protected tryptamine, the title compound was achieved in 21 steps in 3.4 % overall yield. Key steps of the synthesis include: a) the addition of a malonate to a 3‐bromooxindole to afford 3,3‐disubstituted oxindole, b) the formation of a 12‐membered cyclic enol ether by intramolecular O‐propargylation, immediately followed by propargyl Claisen rearrangement to provide the α‐allenyl ketone stereospecifically, c) DMDO oxidation to install a hydroxy group in a highly stereoselective manner, and d) the SmI2‐mediated reductive C−O bond cleavage to remove the α‐keto carboxyl group.
Ultrafast Delamination of Graphite into High‐Quality Graphene Using Alternating Currents
Authors: Yang Sheng , Ricciardulli Antonio Gaetano , Liu Shaohua , Dong Renhao , Lohe Martin R. , Becker Alfons , Squillaci Marco A. , Samorì Paolo , Müllen Klaus , Feng Xinliang
Published: May 2017

To bridge the gap between laboratory‐scale studies and commercial applications, mass production of high quality graphene is essential. A scalable exfoliation strategy towards the production of graphene sheets is presented that has excellent yield (ca. 75 %, 1–3 layers), low defect density (a C/O ratio of 21.2), great solution‐processability, and outstanding electronic properties (a hole mobility of 430 cm2 V−1 s−1). By applying alternating currents, dual exfoliation at both graphite electrodes enables a high production rate exceeding 20 g h−1 in laboratory tests. As a cathode material for lithium storage, graphene‐wrapped LiFePO4 particles deliver a high capacity of 167 mAh g−1 at 1 C rate after 500 cycles.
Transformation of Rusty Stainless‐Steel Meshes into Stable, Low‐Cost, and Binder‐Free Cathodes for High‐Performance Potassium‐Ion Batteries
Authors: Zhu Yun‐hai , Yin Yan‐bin , Yang Xu , Sun Tao , Wang Sai , Jiang Yin‐shan , Yan Jun‐min , Zhang Xin‐bo
Published: May 2017

To recycle rusty stainless‐steel meshes (RSSM) and meet the urgent requirement of developing high‐performance cathodes for potassium‐ion batteries (KIB), we demonstrate a new strategy to fabricate flexible binder‐free KIB electrodes via transformation of the corrosion layer of RSSM into compact stack‐layers of Prussian blue (PB) nanocubes (PB@SSM). When further coated with reduced graphite oxide (RGO) to enhance electric conductivity and structural stability, the low‐cost, stable, and binder‐free RGO@PB@SSM cathode exhibits excellent electrochemical performances for KIB, including high capacity (96.8 mAh g−1), high discharge voltage (3.3 V), high rate capability (1000 mA g−1; 42 % capacity retention), and outstanding cycle stability (305 cycles; 75.1 % capacity retention).
Copper(I)‐Catalyzed Enantioselective Nucleophilic Borylation of Aliphatic Ketones: Synthesis of Enantioenriched Chiral Tertiary α‐Hydroxyboronates
Authors: Kubota Koji , Osaki Shun , Jin Mingoo , Ito Hajime
Published: May 2017

A new method was developed for the first catalytic enantioselective borylation of aliphatic ketones. A variety of substrates reacted efficiently with bis(pinacolato)diboron in the presence of a copper(I)/chiral N‐heterocyclic carbene complex catalyst to furnish optically active tertiary α‐hydroxyboronates with moderate to high enantioselectivities (up to 94 % ee). Notably, the product could be converted into the chiral tertiary alcohol derivative using a stereospecific boron functionalization process. The theoretical study of the mechanism for the enantioselectivity is also described.
Mizoroki–Heck Cyclizations of Amide Derivatives for the Introduction of Quaternary Centers
Authors: Medina Jose M. , Moreno Jesus , Racine Sophie , Du Shuaijing , Garg Neil K.
Published: May 2017

We report non‐decarbonylative Mizoroki–Heck reactions of amide derivatives. The transformation relies on the use of nickel catalysis and proceeds using sterically hindered tri‐ and tetrasubstituted olefins to give products containing quaternary centers. The resulting polycyclic or spirocyclic products can be obtained in good yields. Moreover, a diastereoselective variant of this method gives access to an adduct bearing vicinal, highly substituted sp3 stereocenters. These results demonstrate that amide derivatives can be used as building blocks for the assembly of complex scaffolds.
Mechanical Deformation Accelerates Protein Ageing
Authors: Valle‐Orero Jessica , Rivas‐Pardo Jaime Andrés , Tapia‐Rojo Rafael , Popa Ionel , Echelman Daniel J. , Haldar Shubhasis , Fernández Julio M.
Published: May 2017

A hallmark of tissue ageing is the irreversible oxidative modification of its proteins. We show that single proteins, kept unfolded and extended by a mechanical force, undergo accelerated ageing in times scales of minutes to days. A protein forced to be continuously unfolded completely loses its ability to contract by folding, becoming a labile polymer. Ageing rates vary among different proteins, but in all cases they lose their mechanical integrity. Random oxidative modification of cryptic side chains exposed by mechanical unfolding can be slowed by the addition of antioxidants such as ascorbic acid, or accelerated by oxidants. By contrast, proteins kept in the folded state and probed over week‐long experiments show greatly reduced rates of ageing. We demonstrate a novel approach whereby protein ageing can be greatly accelerated: the constant unfolding of a protein for hours to days is equivalent to decades of exposure to free radicals under physiological conditions.
Yttrium fumaropimarat as a novel heat stabilizer for poly(vinyl chloride)
Authors: Wang Yongqiang , Huang Qiliang
Published: May 2017

Yttrium fumaropimarat (YFPA) was synthesized with fumaropimaric acid and yttrium acetate as raw materials. The structure of the product was analyzed and characterized by Fourier transform infrared spectrometer, scanning electron microscope, energy dispersive X‐ray microanalysis, and X‐ray diffraction. The results showed that the product was amorphous state, three‐dimensional reticulation compound by the ionic bond of COO− and Y3+. The effect of YFPA on poly(vinyl chloride) (PVC) thermal stability was researched by means of Congo red method and heat oven aging method. The experimental results showed that YFPA was a good long‐term PVC thermal stabilizer and could greatly improve PVC thermal stability and initial stage stainability mixing calcium stearate, zinc stearate, and pentaerythrite. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45015.
Bone morphogenetic protein‐2 immobilization on porous PCL‐BCP‐Col composite scaffolds for bone tissue engineering
Authors: Song Myeong‐Jin , Amirian Jhaleh , Linh Nguyen Thuy Ba , Lee Byong‐Taek
Published: May 2017

The objective of this study was to develop novel porous composite scaffolds for bone tissue engineering through surface modification of polycaprolactone–biphasic calcium phosphate‐based composites (PCL–BCP). PCL–BCP composites were first fabricated with salt‐leaching method followed by aminolysis. Layer by layer (LBL) technique was then used to immobilize collagen (Col) and bone morphogenetic protein (BMP‐2) on PCL–BCP scaffolds to develop PCL–BCP–Col–BMP‐2 composite scaffold. The morphology of the composite was examined by scanning electron microscopy (SEM). The efficiency of grafting of Col and BMP‐2 on composite scaffold was measured by X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Both XPS and FTIR confirmed that Col and BMP‐2 were successfully immobilized into PCL–BCP composites. MC3TC3‐E1 preosteoblasts cells were cultivated on composites to determine the effect of Col and BMP‐2 immobilization on cell viability and proliferation. PCL–BCP–Col–BMP‐2 showed more cell attachment, cell viability, and proliferation bone factors compared to PCL–BCP‐Col composites. In addition, in vivo bone formation study using rat models showed that PCL–BCP–Col–BMP‐2 composites had better bone formation than PCL–BCP‐Col scaffold in critical size defect with 4 weeks of duration. These results suggest that PCL–BCP–Col–BMP‐2 composites can enhance bone regeneration in critical size defect in a rat model with 4 weeks of duration. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45186.
Long‐term cost of spouses’ informal support for dependent midlife stroke survivors
Authors: Persson Josefine , Levin Lars‐Åke , Holmegaard Lukas , Redfors Petra , Svensson Mikael , Jood Katarina , Jern Christina , Blomstrand Christian , Forsberg‐Wärleby Gunilla
Published: May 2017

Objectives

Stroke is a major global disease that requires extensive care and support from society and relatives. The aim of this study was to identify and quantify the long‐term informal support and to estimate the annual cost of informal support provided by spouses to their stroke surviving partner.

Method

Data were based on the 7‐year follow‐up of the Sahlgrenska Academy Study on Ischemic Stroke. One‐third of the spouses stated that they provided support to their stroke surviving partner. The magnitude of the support was assessed with a study‐specific time‐diary and was estimated for independent and dependent stroke survivors based on the scores of the modified Rankin Scale. To deal with skewed data, a two‐part econometric model was used to estimate the annual cost of informal support.

Result

Cohabitant dyads of 221 stroke survivors aged <70 at stroke onset were included in the study. Spouses of independent stroke survivors (n = 188) provided on average 0.15 hr/day of practical support and 0.48 hr/day of being available. Corresponding figures for spouses of dependent stroke survivors (n = 33) were 5.00 regarding practical support and 9.51 regarding being available. The mean annual cost of informal support provided for independent stroke survivors was estimated at €991 and €25,127 for dependent stroke survivor.

Conclusion

The opportunity cost of informal support provided to dependent midlife stroke survivors is of a major magnitude many years after stroke onset and should be considered in economic evaluations of health care.
A comparison of three methods of measuring tibial torsion in children with myelomeningocele and normally developing children
Authors: Borish Cassie N. , Mueske Nicole M. , Wren Tishya A.L.
Published: May 2017

Abnormal tibial torsion is a common pediatric problem, and there are many existing measurement methods. The purpose of this study was to compare three methods of measuring tibial torsion for its evaluation: computed tomography, physical examination, and motion capture. Twenty healthy children and 20 children with myelomeningocele underwent measures of tibial torsion bilaterally. Measurements were compared using correlation and Bland–Altman plots of the difference between measurements. All three measurements were moderately correlated in controls (r ≥ 0.49, P ≤ 0.002) and in patients (r ≥ 0.51, P ≤ 0.001). In controls, the motion capture measurements were on average 2° more lateral than the clinical measurements whereas motion capture and clinical measurements were 13° and 15° more medial than CT measurements, respectively. Similarly for patients, motion capture measurements were on average 5° more medial than clinical measurements, and motion capture and clinical measurements were 26° and 22° more medial than CT measurements. The approximate 20° difference between the clinical or motion capture measures and the CT measure suggests that clinical evaluation identifies different axes than those defined based on skeletal anatomy. Clinical or motion capture methods may be used in lieu of imaging methods for measuring tibial torsion with the knowledge that these methods provide less lateral measurements than measurements obtained using CT. Clin. Anat. :1043–1048, 2017. © 2017 Wiley Periodicals, Inc.
Hybrid modeling of multiphysical processes for particle‐based volcano animation
Authors: Zhang Shenfan , Kong Fanlong , Li Chen , Wang Changbo , Qin Hong
Published: May 2017

Many complex natural phenomena with dramatic spatial and temporal variation are difficult to animate accurately with anticipated performance in many graphics tasks and applications, because oftentimes in prior art, a single type of physical process could not afford high fidelity and effective scene production. Volcano eruption and its subsequent interaction with earth is one such complicated phenomenon that must depend on multiphysical processes and their tight coupling. This paper documents a novel and effective particle‐based solution for volcano animation that embraces multiphysical processes and their tight unification. First, we introduce a governing physical model consisting of multiphysical processes enabling flexible state transition among solid, fluid, and gas. This computational physics model is dictated by temperature and accommodates dynamic viscosity that is changing according to the temperature. Second, we propose an augmented smoothed particle hydrodynamics as the underlying numerical model to simulate the behavior of lava and smoke with several required physical attributes. Third, multiphysical quantities are tightly coupled to support the interaction with surroundings including fluid–solid coupling, ground friction, and lava–smoke coupling. We also develop a temperature‐directed rendering technique with nearly no extra computational cost and demonstrate realistic graphics effects of volcano eruption and its interaction with earth with visual appeal.
Feedback control of fire simulation based on computational fluid dynamics
Authors: Sato Syuhei , Mizutani Keisuke , Dobashi Yoshinori , Nishita Tomoyuki , Yamamoto Tsuyoshi
Published: May 2017

Visual simulation of fire plays an important role in many applications, such as movies and computer games. In these applications, artists are often requested to synthesize realistic fire with a particular behavior. To meet such requirement, we present a feedback control method for fire simulations. The user can design the shape of fire by placing a set of control points. Our method generates a force field and automatically adjusts a temperature at a fire source, based on user specified control points. Experimental results show that our method can control the fire shape.
Visual simulation of rapidly freezing water based on crystallization
Authors: Im Jaeho , Kim Jong‐Hyun , Kim Wook , Park Nuri , Kim Taehyeong , Kim Young Bin , Lee Jung , Kim Chang‐Hun
Published: May 2017

We propose a physics‐inspired simulation framework that expresses visual effects of flowing water frozen in glaze or directional icicles. The proposed ice model considers the direction of the water flow, which affects the growth of icicles. Water dynamics are computed using a conventional particle‐based simulation. Ice glaze and directional icicles are generated by incorporating our freezing solver. To determine whether a water particle is converted into ice or remains liquid, we compute the nucleation energy based on the humidity and water flow. The humidity is approximated as a virtual water film on object surfaces. The water flow is incorporated by introducing a growth direction vector to guide the direction of icicle growth. Ice‐generating regions can be controlled using 3‐D modeling tools such as Autodesk Maya or 3DS Max. Experiments showed that a realistic ice glaze was created on the surfaces of objects and that icicles grew in the direction of the water flow.
Chemical Composition and Antimicrobial Activity of Essential Oils from the Aerial Parts of Asteriscus graveolens (Forssk.) Less. and Pulicaria incisa (Lam.) DC.: Two Asteraceae Herbs Growing Wild in the Hoggar
Authors: Chaib Faiza , Allali Hocine , Bennaceur Malika , Flamini Guido
Published: May 2017

In recent years, antimicrobial activities of essential oils have been intensively explored, mainly in researching and developing new antimicrobial agents to overcome microbial resistance. The present study investigates the chemical composition and antimicrobial activities of essential oils obtained from two Asteraceae: Asteriscus graveolens (Forssk.) Less. and Pulicaria incisa (Lam.) DC. Chemical analysis was performed using a combination of capillary GC‐FID and GC/MS analytical techniques. The major component of Asteriscus graveolens were cis‐chrysanthenyl acetate (31.1%), myrtenyl acetate (15.1%), and kessane (11.5%), while for Pulicaria incisa the main components were chrysanthenone (45.3%) and 2,6‐dimethylphenol (12.6%). The oils obtained from the aerial parts were tested against sixteen microbial strains by agar well diffusion technique and dilution methods and showed minimum inhibitory concentrations (MIC) in the range of 19 – 1250 μg/ml. A good antibacterial activity against a common nosocomial pathogen, Acinetobacter baumanniiATCC 19606 was observed, especially from Pulicaria incisa essential oil, with a MIC value up to 19 μg/ml. These results give significant information about the pharmacological activity of these essential oils, which suggest their benefits to human health, having the potential to be used for medical purposes.
Bisphenol A triggers proliferation and migration of laryngeal squamous cell carcinoma via GPER mediated upregulation of IL‐6
Authors: Li Shisheng , Wang Bin , Tang Qinglai , Liu Jiajia , Yang Xinming
Published: May 2017

Bisphenol A (BPA) can be accumulated into the human body via food intake and inhalation. Numerous studies indicated that BPA can trigger the tumorigenesis and progression of cancer cells. Laryngeal cancer cells can be exposed to BPA directly via food digestion, while there were very limited data concerning the effect of BPA on the development of laryngeal squamous cell carcinoma (LSCC). Our present study revealed that nanomolar BPA can trigger the proliferation of LSCC cells. Bisphenol A also increased the in vitro migration and invasion of LSCC cells and upregulated the expression of matrix metallopeptidase 2. Among various chemokines tested, the expression of IL‐6 was significantly increased in LSCC cells treated with BPA for 24 hours. Neutralization antibody of IL‐6 or si–IL‐6 can attenuate BPA‐induced proliferation and migration of LSCC cells. Targeted inhibition of G protein–coupled estrogen receptor, while not estrogen receptor (ERα), abolished BPA‐induced IL‐6 expression, proliferation, and migration of LSCC cells. The increased IL‐6 can further activate its downstream signal molecule STAT3, which was evidenced by the results of increased phosphorylation and nuclear translocation of STAT3, while si–IL‐6 and si‐GPER can both reverse BPA‐induced activation of STAT3. Collectively, our present study revealed that BPA can trigger the progression of LSCC via GPER‐mediated upregulation of IL‐6. Therefore, more attention should be paid for the BPA exposure on the development of laryngeal cancer.
Conversion of Carbon Dioxide into Oxazolidinones Mediated by Quaternary Ammonium Salts and DBU
Authors: Lv Min , Wang Peng , Yuan Dan , Yao Yingming
Published: May 2017

A straightforward method to construct oxazolidinones through a three‐component reaction involving CO2, epoxides, and amines promoted by a combination of Bu4NI and 1,8‐diazabicyclo[5.4.0]undec‐7‐ene was developed. A wide range of aromatic and aliphatic amines and monosubstituted epoxides were converted into 3,5‐disubstituted‐2‐oxazolidines in up to 95 % yield. This metal‐free and easily available catalytic system was applicable to a broad range of substrates, including conventionally challenging ones such as aliphatic epoxides, at atmospheric pressure. Preliminary mechanistic studies suggested a reaction pathway involving β‐amino alcohols.
Investigation of Mass Transfer and Hydrodynamics in a Model Bubble Column
Authors: Kováts Péter , Thévenin Dominique , Zähringer Katharina
Published: May 2017

Gas‐liquid mass transfer in bubble columns is strongly influenced by the flow field in the column. The underlying transport processes are often the limiting factor. Since bubble columns are widely used in the chemical process industry, it is essential to quantify how the dispersed gas can come into reaction with the liquid phase through gas‐liquid mass transfer. CO2 bubble swarms in a cylindrical model bubble column are considered. Optical measurement methods are used for the non‐intrusive measurement of velocity and pH change, resulting from the dissolution of CO2 in the liquid phase. The mean and fluctuating velocity components in the center plane of the column as well as the time‐dependent pH fields in this plane are determined. From these quantities, derived values characterizing the mass transfer from gaseous CO2 to the liquid phase can be calculated.
Effect of Alkyl Chain Length on the Sensitizing Action of Substituted Non‐Symmetric Squaraines for p‐Type Dye‐Sensitized Solar Cells
Authors: Bonomo Matteo , Saccone Davide , Magistris Claudio , Di Carlo Aldo , Barolo Claudia , Dini Danilo
Published: May 2017

The design and the synthesis of three unsymmetrical squaraines, DS_34, DS_45, and DS_47, have been achieved for their utilization as sensitizers of screen‐printed NiO cathodes in p‐type dye‐sensitized solar cells (p‐DSCs). DS_34, DS_45, and DS_47 are bidentate dyes, each bearing two carboxylic anchoring groups, which differ solely in the length of alkyl chain attached to the nitrogen atom of the condensed pyrrole ring (ethyl, butyl, and dodecyl for DS_45, DS_34, and DS_47, respectively). The photoelectrochemical properties of the corresponding p‐DSCs are compared and analyzed in terms of the structural differences of DS_34, DS_45, and DS_47. The benchmark dye, p‐SQ2, has also been employed as a p‐DSC sensitizer for the sake of comparison. Current density−voltage (JV) curves and incident photon‐to‐current conversion efficiency (IPCE) spectra revealed the major efficaciousness of the DS_45 as a dye‐sensitizer, as it was the only system that produced a p‐DSC surpassing 0.04 % of overall efficiency (η). This finding was attributed mainly to the larger surface concentration of chemisorbed DS_45 with respect to the other squaraines.
Periodic Transition between Breathing Spots and Synchronous Sulfur Deposition/Dissolution in Transpassive Region of the Electro‐Oxidation of Sulfide on Platinum
Authors: Pan Changwei , Cheng Ruolan , Birzu Adrian , Yang Jiaping , Ren Lin , Varela Hamilton , Gao Qingyu
Published: May 2017

In the transpassive region of sulfide electro‐oxidation on platinum, the system displayed different complex oscillations under potentiostatic control experiments, changing from quasiperiodic small oscillations to alternate modes between small and large amplitude oscillations for increasing applied voltages. In each period of the alternating‐mode oscillations, the current density evolves from a slightly decreasing steady state to small and large amplitude oscillations. Spatiotemporal patterns developed on the platinum disk were recorded with a CCD camera and ranged from breathing spots to alternating patterns between breathing spots and synchronous deposition/dissolution. Karhunen‐Loève decomposition analysis of the experimental patterns showed that the twinkling patterns had multiple modes each with a low percentage of energy, whereas the alternate patterns were mainly characterized by one dominant mode.
Multinuclear Phthalocyanine‐Fused Molecular Nanoarrays: Synthesis, Spectroscopy, and Semiconducting Property
Authors: Shang Hong , Xue Zheng , Wang Kang , Liu Huibiao , Jiang Jianzhuang
Published: May 2017

The post‐cyclization strategy rather than the conventional ante‐cyclotetramerization method was employed for the synthesis of multinuclear phthalocyanine‐fused molecular nanoarrays. Reaction of 2,3,9,10,16,17‐hexakis(2,6‐dimethylphenoxy)‐23,24‐diaminophthalocyaninato zinc(II) with 2,7‐di‐tert‐butylpyrene‐4,5‐dione, 2,7‐di‐tert‐butylpyrene‐4,5,9,10‐tetraone, and hexaketocyclohexane in refluxing acetic acid afforded the corresponding mono‐, bi‐, and trinuclear phthalocyanine‐fused zinc complexes (Pz‐pyrene){Zn[Pc(OC8H9)6]} (1), (Pz2‐pyrene){Zn[Pc(OC8H9)6]}2 (2), {(HAT){Zn[Pc(OC8H9)6]}3} (3) in 46, 13, and 25 % yield, respectively, which extend the scope of multinuclear phthalocyanine‐fused nanoarrays with different molecular skeletons. The self‐assembly behavior of trinuclear phthalocyanine 3 in THF/CH3CN was investigated by electronic absorption spectroscopy and SEM, and the fabricated nanorods showed interesting semiconducting properties, which suggest good application potential of these multinuclear phthalocyanine‐fused molecular nanoarrays.
Zinc‐Coordinated Hierarchical Organization of Ligand‐Stabilized Gold Nanoclusters for Chiral Recognition and Separation
Authors: Basu Srestha , Paul Anumita , Chattopadhyay Arun
Published: May 2017

Three‐dimensional organization of d‐ or l‐tryptophan and mercaptopropionic acid‐stabilized gold nanoclusters has been achieved by complexation of ligands using zinc ions. Powder X‐ray diffraction and transmission electron microscopy analyses substantiated the crystalline nature of the assembly of atomic nanoclusters. The hierarchical arrangement of the nanoclusters exhibited superior optical properties (namely, enhanced photoluminescence and excited‐state lifetime) as compared to the non‐assembled nanoclusters. Furthermore, photoluminescence of the crystalline assembly of nanoclusters served as a visual marker for chiral recognition of d and l enantiomers of tryptophan, with subsequent separation of the corresponding enantiomer. A theoretical structure based on various experimental observations has also been proposed herein. The mechanistic aspect of the chiral separation is proposed to have occurred through attachment of d or l‐tryptophan to the coordinatively unsaturated zinc ions, thus forming super complexes. The degree of stabilization of the super complexes is dictated by a “three‐point versus two‐point” interaction between the enantiomers and the chiral selector.
Supramolecular Isomers of Coordination‐Directed Side‐Chain Polypseudorotaxanes Based on Trimeric Uranyl Oxalate Nodes
Authors: Ge Yun‐chen , Mei Lei , Xie Zhen‐ni , Hu Kong‐qiu , Xia Chuan‐qin , Wang Xiao‐lin , Chai Zhi‐fang , Shi Wei‐qun
Published: May 2017

Although the prosperity of rotaxane coordination polymers with rotaxane molecules serving as main‐chain linkers is known, side‐chain metal‐organic polypseudorotaxanes incorporating macrocyclic host molecules have not been reported to date. Herein a new type of coordination‐driven cucurbit[6]uril‐bearing side‐chain polypseudorotaxane, with two‐dimensional trimeric uranyl‐oxalate as main chains, has been synthesized. This was carried out through hydrothermal reactions of uranyl components with an in situ‐formed carboxylated pseudorotaxane ligand in the presence of oxalate co‐ligands. Varying the substitution site of coordination groups led to two different supramolecular isomers. Further mechanistic analysis indicated that condition‐dependent hydrolysis of the cyano groups of the pseudorotaxane ligand, as well as the participation of oxalate groups into the coordination sphere of uranyl moieties, contributes to the formation of this new type of side‐chain polypseudorotaxane.
Charged Macromolecular Rhenium Bipyridine Catalysts with Tunable CO2 Reduction Potentials
Authors: Sahu Swagat , Cheung Po Ling , Machan Charles W. , Chabolla Steven A. , Kubiak Clifford P. , Gianneschi Nathan C.
Published: May 2017

A series of polymeric frameworks with functional assemblies were designed to alter the catalytic activity of covalently bound ReI electrocatalysts. Norbornenyl polymers containing positively charged quaternary ammonium salts, neutral phenyl, or negatively charged trifluoroborate groups were end‐labelled with a ReI fac‐tricarbonyl bipyridine electrocatalyst via cross metathesis. Electrochemical studies in acetonitrile under an inert atmosphere and with saturated CO2 indicate that the quaternary ammonium polymers exhibit a significantly lower potential for CO2 reduction to CO (ca. 300 mV), while neutral polymers behave consistently with what has been reported for the free, molecular catalyst. In contrast, the trifluoroborate polymers displayed a negative shift in potential and catalytic activity was not observed. It is demonstrated that a single catalytically active complex can be installed onto a charged polymeric framework, thereby achieving environmentally tuned reduction potentials for CO2 reduction. These materials may be useful as polymer‐based precursors for preparing catalytic and highly ordered structures such as thin films, porous catalytic membranes, or catalytic nanoparticles.
DNA Release from Fe3+‐Cross‐Linked Alginate Films Triggered by Logically Processed Biomolecular Signals: Integration of Biomolecular Computing and Actuation
Authors: Gamella Maria , Privman Marina , Bakshi Saira , Melman Artem , Katz Evgeny
Published: May 2017

Signal‐controlled release of DNA from Fe3+‐cross‐linked alginate hydrogel electrochemically deposited on an electrode surface was studied. The multiple input signals were logically processed with the help of the enzyme‐biocatalyzed reactions. Boolean logic gates, OR, AND, INH, were realized with the biocatalytic reactions performed by the enzymes entrapped in the alginate film. Hydrogen peroxide produced by the enzymatic reactions resulted in the degradation of the alginate hydrogel and DNA release. The alginate degradation was facilitated by the formation of free radicals in the Fenton‐type reaction catalyzed by iron cations cross‐linking the alginate hydrogel. The studied approach is versatile and can be adapted to various chemical signals processed by various enzymes with differently implemented Boolean logic. This work illustrates a novel concept of functional integration of biomolecular computing and actuation.
Serrated Au/Pd Core/Shell Nanowires with Jagged Edges for Boosting Liquid Fuel Electrooxidation
Authors: Zhang Yu‐Ling , Shen Wen‐Jin , Kuang Wen‐Tao , Guo Shaojun , Li Yong‐Jun , Wang Ze‐Hong
Published: May 2017

Integration of 1D, core/shell, and jagged features into one entity may provide a promising avenue for further enhancing catalyst performance. However, designing such unique nanostructures is extremely challenging. Herein, 1D serrated Au/Pd core/shell nanowires (CSNWs) with jagged edges were produced simply by a one‐pot, dual‐capping‐agent‐assisted method involving co‐reduction, galvanic replacement, directional coalescence of preformed nanoparticles, and site‐selective epitaxial growth of Pd. Au/PdCSNWs, compared with the commercially available Pd/C, exhibited enhanced electrocatalytic performance towards liquid fuel oxidation because of the synergistic effect of the electronic structure and low‐coordinated jagged edges.
Diverse roles for the ror‐family receptor tyrosine kinases in neurons and glial cells during development and repair of the nervous system
Authors: Endo Mitsuharu , Minami Yasuhiro
Published: May 2017

The Ror‐family of receptor tyrosine kinases (RTKs) are involved critically in tissue genesis and organogenesis during development. In mammals, Ror1 and Ror2, members of the Ror‐family RTKs, have been shown to mediate cell polarity, migration, proliferation, and differentiation through the activation of noncanonical Wnt signaling by acting as receptors or co‐receptors for Wnt5a. Nematodes bearing mutations within the cam‐1 gene, encoding a Ror2 ortholog, exhibit defects in various developmental processes of the nervous system, including neuronal cell migration, polarization, axonal extension, and synaptic transmission. In mice, Ror2 and/or Ror1 are also shown to play roles in regulating neurite extension, synapse formation, and synaptic transmission of hippocampal neurons, indicating that the Ror‐family RTKs have evolutionarily conserved functions at least in part in neurons during development. Furthermore, Ror2 and/or Ror1 are expressed in neural stem/progenitor cells of the developing brain and in astrocytes of the adult brain after injury, and they play important roles in regulating cell proliferation under these different contexts. In this article, we overview recent advances in our understanding of the roles of the Ror‐family RTKs in the development and repair of the nervous system and discuss their potential for therapeutic targets to neurodegenerative diseases. Developmental Dynamics 247:24–32, 2018. © 2017 Wiley Periodicals, Inc.
Synergistic Effect in Green Extraction of Noble Metals and Its Consequences
Authors: Nag Abhijit , Baksi Ananya , Krishnapriya K. C. , Gupta Soujit Sen , Mondal Biswajit , Chakraborty Papri , Pradeep Thalappil
Published: May 2017

Extraction of silver into water occurs from its apparently inert metal surface by the simple carbohydrate glucose. Here we show that there are large synergistic effects in the extraction process, which results in ca. 45 times larger leaching with specific molecules, when used along with glucose. While glucose (1 g) alone can extract ca. 650 ppb of silver from the metal, 60 mg of it extracts ca. 30000 ppb in a combination with 200 mg of glutathione (GSH) under similar experimental conditions of 70 °C and an extraction time of 7 d, in deionized (DI) water (200 mL). This enhancement is similar when glucose is replaced with cyclodextrin (CD). This enhanced concentration of silver in solution enables the formation of the silver clusters protected with glutathione and cyclodextrin, Ag20(SG)15CD3–, in the presence of a reducing agent. A similar extraction for copper leads to excessive leaching, and typical concentrations are even higher than the solubility limit of the copper–glutathione complex. As a result, these complexes are precipitated. This synergistic extraction is observed for zinc and stainless steel as well. Enhanced extraction is a result of the formation of complexes of metals with glutathione and the consequent leaching of the complex into solution as well as the stabilization of the complex by inclusion complexation with cyclodextrin. Enhanced leaching in the presence of glucose is mostly due to simultaneous complexation with glucose as well as glutathione. The science presented may be used for the green extraction of different metals and could be a new potential top‐down approach for metal cluster synthesis. This may also be useful for green and sustained leaching of minerals into water to regulate its quality.
Dicationic Ruthenium(II)–Arene–Curcumin Complexes Containing Methylated 1,3,5‐Triaza‐7‐phosphaadamantane: Synthesis, Structure, and Cytotoxicity
Authors: Pettinari Riccardo , Condello Francesca , Marchetti Fabio , Pettinari Claudio , Smoleński Piotr , Riedel Tina , Scopelliti Rosario , Dyson Paul J.
Published: May 2017

Dicationic ruthenium(II)–p‐cymene complexes containing curcumin ligands (curcH = curcumin, bdcurcH = bisdemethoxycurcumin) and ionic N‐methyl‐1,3,5‐triaza‐7‐phosphaadamantane [PTA‐Me]X (X = BF4 or I) have been synthesized and fully characterized for the first time. The solid‐state structure of [Ru(p‐cym)(curc)(PTA‐Me)][SO3CF3][BF4] has also been determined by single‐crystal X‐ray diffraction. Modest antiproliferative activities of the complexes were observed against cisplatin‐sensitive and cisplatin‐resistant human ovarian carcinoma cells (A2780 and A2780cisR, respectively) and nontumorigenic human embryonic kidney (HEK293) cells.
Coagulative Behaviour of Jatropha curcas and its Performance in Wastewater Treatment
Authors: Abidin Zurina Z. , Madehi Norhafizah , Yunus Robiah
Published: May 2017

Alternative natural coagulants from Jatropha curcas seed and press cake were investigated for coagulative behaviors and abilities to treat real wastewater. The characterization of the seed and press cake was done by proximate analysis while characterization on extracts which contain the active coagulant agent was conducted using FTIR, amino acid analysis, and zeta potential. The coagulation performance was evaluated using Jar Floc test on palm oil mill effluent. Proximate analysis indicated that Jatropha seed contained more protein (54%) than press cake (28%). Through HPLC analysis, 18 types of amino acid were detected in Jatropha curcas (JC) seed and press cake extracts. FTIR results confirmed the functional groups that existed in all the amino acids. The zeta potential of the extracts was positive at pH < 3 and became negative as pH increased. This means that the bio‐coagulant possessed net positive and negative charge at pH < 3 and pH > 4, respectively. Hence, the mechanism of coagulation at pH < 3 is due to adsorption and neutralization whereas at pH > 4, adsorption and interparticle bridging dominates. Dosages of 140 mg L−1 of Jatropha seed and 120 mg L−1 of press cake were required to treat 3500 NTU of POME to give 99 and 93% turbidity removal, respectively. Jatropha seed gave maximum turbidity removal at pH 3, while press cake at pH 2. The final pH of the treated POME was not altered greatly and the sludge produced was lesser in comparison to alum. In conclusion, the protein was the compound responsible for Jatropha coagulating behavior and its ability to treat real wastewater is promising. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1709–1718, 2017
Simultaneous energy harvesting and information processing considering multi‐relay multi‐antenna using maximum ratio transmission and antenna selection strategies
Authors: Zahedi Abdulhamid , Lari Mohammad , Albaaj Azhar , Alabkhat Qassem
Published: May 2017

Wireless networks suffer from battery discharging specially in cooperative communications when multiple relays have an important role but they are energy‐constrained. To overcome this problem, energy harvesting from Radio Frequency signals is applied to charge the node battery. These intermediate nodes have the ability to harvest energy from the source signal and use the harvested energy to transmit information to the destination. Simultaneous energy harvesting and data transmission can be done in multi‐relay systems. Each relay dedicates a part of time or power for energy harvesting, and the remainder part is devoted for data transmission. Based on time or power division, 2 relaying protocols known as time switching based relaying protocol or power splitting based relaying protocol exist. These 2 protocols can also be applied in delay‐limited and delay‐tolerant transmission systems. The previous works have assumed a single relay or single antenna for energy harvesting, but in this paper, the proposed method is concentrated on improving the throughput by using multiple antennas in multi‐relay system. Two strategies of selecting the signal of multiple antennas for transmission known as maximum ratio transmit and Antenna selection has been used in this paper. Maximum ratio transmit combines the signals of antennas but Antenna selection selects the antenna with maximum signal‐to‐noise ratio. According to our simulation results, when using multi‐antenna relays, ability of energy harvesting is increased compared with single‐relay or single‐antenna system and thus the system performance will be improved considerably. Also, maximum ratio transmit method has better performance compared with Antenna Selection one.
Sperm storage by males causes changes in sperm phenotype and influences the reproductive fitness of males and their sons
Authors: Gasparini Clelia , Dosselli Ryan , Evans Jonathan P.
Published: May 2017

Recent studies suggest that environmentally induced effects on sperm phenotype can influence offspring phenotype beyond the classic Mendelian inheritance mechanism. However, establishing whether such effects are conveyed purely through ejaculates, independently of maternal environmental effects, remains a significant challenge. Here, we assess whether environmentally induced effects on sperm phenotype affects male reproductive success and offspring fitness. We experimentally manipulated the duration of sperm storage by males, and thus sperm age, in the internally fertilizing fish Poecilia reticulata. We first confirm that sperm ageing influences sperm quality and consequently males reproductive success. Specifically, we show that aged sperm exhibit impaired velocity and are competitively inferior to fresh sperm when ejaculates compete to fertilize eggs. We then used homospermic (noncompetitive) artificial insemination to inseminate females with old or fresh sperm and found that male offspring arising from fertilizations by experimentally aged sperm suffered consistently impaired sperm quality when just sexually mature (four months old) and subsequently as adults (13 months old). Although we have yet to determine whether these effects have a genetic or epigenetic basis, our analyses provide evidence that environmentally induced variation in sperm phenotype constitutes an important source of variation in male reproductive fitness that has far reaching implications for offspring fitness.
The coadaptation theory for genomic imprinting
Authors: O'Brien Eleanor K. , Wolf Jason B.
Published: May 2017

Imprinted genes are peculiar in that expression of the two copies differs depending on whether the copy was maternally or paternally inherited. The discovery of this striking pattern of gene expression inspired myriad evolutionary theories, the most successful of which identify scenarios that create an asymmetry between the maternally and paternally inherited gene copies that favors silencing of one of the copies. Most notably, imprinting can evolve when gene dosage affects kin interactions (typically involving conflict) or when silencing enhances coadaptation by coordinating traits expressed by interacting kin. Although we have a well-established theory for the former process (the “Kinship Theory”), the coadaptation process has only been explored for the specific case of interactions between mothers and offspring. Here, we fill this critical gap in our understanding by developing a general “Coadaptation Theory” that explains how imprinting can evolve to coordinate interactions between all types of relatives. Using a simple model in which fitness of an individual is determined by an interaction between its own phenotype (and hence genotype) and that of its social partner(s), we find that when the relatedness of interactants differs through their maternally versus paternally inherited gene copies, then selection favors expression of the allele through which relatedness is higher. The predictions of this Coadaptation Theory potentially apply whenever a gene underlies traits that mediate the outcome of conspecific interactions, regardless of their mechanism or the type of organism, and therefore provide a potential explanation for enigmatic patterns of imprinting, including those underlying adult traits. By providing simple testable predictions that often directly contrast with those derived from alternative theories, our model should play an important role in consolidating our understanding of the evolution of imprinting across genes and species, which will ultimately provide crucial insights into imprinted gene function and dysfunction.
Initiating activities of daily living contributes to well‐being in people with dementia and their carers
Authors: Giebel Clarissa M. , Sutcliffe Caroline
Published: May 2017

Objective

Problems with everyday functioning are linked to reduced well‐being in people with dementia (PwD) and their carers. However, previous research has almost solely investigated the performance of everyday activities, and global functioning without analysing individual activities. This study explored how deficits in initiating and performing individual activities were associated with carer burden and poorer quality of life of carers and PwD.

Methods

Carers of people with mild dementia were recruited via 10 National Health Service Trusts, as well as through attending six carer support groups. Carers were asked to complete the revised Interview for Deteriorations in Daily Living Activities in Dementia 2 (R‐IDDD2), and measures on carer burden, well‐being, and person with dementia well‐being. Data were analysed using correlation analysis.

Results

Two hundred and seventy‐two carers completed the R‐IDDD2. Carers were grouped into those with low or high ratings of well‐being based on the mean scores. All but three activities on the initiative and/or performance scale were significantly associated with carer burden and carer and PwD quality of life. Engaging in hobbies and maintaining an active social life were most strongly associated with carer and PwD well‐being. Initiating computer use, driving, and medication management were not related to carer burden.

Conclusions

Findings from this study can have direct implications for improving care management early in the disease. Post‐diagnostic support needs to provide more opportunities for PwD, and their carers, to engage in social groups, whilst interventions targeted at living well with dementia need to particularly improve the initiative of engaging in individual hobbies. Copyright © 2017 John Wiley & Sons, Ltd.
Impact of venous outflow tract on survival of osteocutaneous free fibula flaps for mandibular reconstruction: A 14‐year review
Authors: Chang Eric I.
Published: May 2017

Background

The principle reconstructive modality for segmental mandibulectomy defects is the osteocutaneous free fibula flap. Preoperative CT angiography has been recommended to assess the quality of arterial inflow to the flap and donor limb. However, the impact of the venous system on flap viability has not been explored.

Methods

A retrospective review of all patients undergoing free fibula flap mandible reconstruction was performed at a single tertiary cancer center from 2002 to 2015. Overall complications, including operative reexploration and total flap losses, were evaluated.

Results

One hundred seven patients underwent free fibula flap reconstruction of the mandible. Nine patients underwent multiple free flaps and were excluded from this study. Of the remaining 98 patients, 8 patients required operative exploration for microvascular compromise. All patients were found to have venous thrombosis. There were 3 total flaps losses with a salvage rate of 62.5% and overall flap survival of 96.9%. The size of the vena comitantes in the compromised flaps were significantly larger than those of the remaining patients (4.4 mm vs 3.1 mm; P < .0001). Although the total operative times were similar between the 2 groups (585.2 minutes vs 563.3 minutes), the ischemia time was significantly shorter in those cases that required operative takeback (76.5 minutes vs 104.0 minutes; P < .04).

Conclusion

Venous thrombosis of free fibula flaps is more common than arterial thrombosis. Venous stasis in larger vena comitantes may be a contributing factor to microvascular compromise. Anticoagulation and/or handsewn anastomosis may be beneficial if the veins are larger than 4.0 mm in size.