bluuebunny/crossref_metadata_2025 huggingface dataset:
Stable and Highly Efficient PbS Quantum Dot Tandem Solar Cells Employing a Rationally Designed Recombination Layer
Authors: Shi Guozheng , Wang Yongjie , Liu Zeke , Han Lu , Liu Jie , Wang Yakun , Lu Kunyuan , Chen Si , Ling Xufeng , Li Yong , Cheng Si , Ma Wanli
Published: April 2017

This study reports the fabrication of stable, high‐performance, simple structured tandem solar cells based on PbS colloidal quantum dots (CQDs) under ambient air. This study also reveals detailed device engineering to deposit each functional layer in the subcells at low temperature to avoid damage to the PbS CQDs and meanwhile makes the fabrication process compatible to flexible plastic substrate. Two efficient recombination layers (RLs) are rationally designed to connect the two subcells in series. The use of solution‐processed RL with an organic PEDOT:PSS (poly(3,4‐ethylenedioxythiophene): polystyrene sulfonate) interlayer leads to the fabrication of the tandem devices in solution process. The use of robust inorganic RL containing an ultrathin Au interlayer results in more efficient device performance and remarkably improved device lifetime. The optimal PbS CQDs tandem cells based on inorganic RL demonstrate a high power conversion efficiency approaching 9%. This efficiency is more than two times higher than the previous record of 4.2%, which has been kept for more than five years. The remarkable stability, high performance, and low‐temperature processing of these tandem devices may provide insight into the commercialization of flexible and large‐area CQDs tandem solar cells in the near future.
Four‐Terminal Perovskite/Silicon Multijunction Solar Modules
Authors: Jaysankar Manoj , Qiu Weiming , van Eerden Maarten , Aernouts Tom , Gehlhaar Robert , Debucquoy Maarten , Paetzold Ulrich W. , Poortmans Jef
Published: April 2017

Multijunction solar cells employing perovskite and crystalline‐silicon (c‐Si) light absorbers bear the exciting potential to surpass the efficiency limit of market‐leading single‐junction c‐Si solar cells. However, scaling up this technology and maintaining high efficiency over large areas are challenging as evidenced by the small‐area perovskite/c‐Si multijunction solar cells reported so far. In this work, a scalable four‐terminal multijunction solar module design employing a 4 cm2 semitransparent methylammonium lead triiodide perovskite solar module stacked on top of an interdigitated back contact c‐Si solar cell of identical area is demonstrated. With a combination of optimized transparent electrodes and efficient module design, the perovskite/c‐Si multijunction solar modules exhibit power conversion efficiencies of 22.6% on 0.13 cm2 and 20.2% on 4 cm2 aperture area. Furthermore, a detailed optoelectronic loss analysis along with strategies to enhance the performance is discussed.
Distinctive Supercapacitive Properties of Copper and Copper Oxide Nanocrystals Sharing a Similar Colloidal Synthetic Route
Authors: Wu Songhao , Lv Weiqiang , Lei Tianyu , Han Yidong , Jian Xian , Deng Min , Zhu Gaolong , Liu Mingzhen , Xiong Jie , Dickerson James H. , He Weidong
Published: April 2017

CuO and Cu2O are non‐noble transition metal oxide supercapacitive materials with high theoretical specific capacitances above 1800 F g−1. In this work, by adjusting organic additives of a colloidal system, Cu, Cu2O, and CuO are grown in situ on nickel foam. CuO exhibits a specific capacitance of 1355 F g−1 at 2 A g−1 in 3 m KOH, a value well above those of Cu and Cu2O (<500 F g−1), and is superior to other known CuO electrodes. The CuO electrode exhibits 70% of its initial capacity, and the Columbic efficiency remains ≈100% after 7000 cycles at 4 A g−1. Cu2O exhibits the worst electrochemical performance, mainly due to the inactive barrier layer forming on the surface. This work provides an efficient synthetic platform for both comparable supercapacitive studies and cost‐effective electrochemical energy storage applications.
Facile synthesis of Pd@Pt octahedra supported on carbon for electrocatalytic applications
Authors: Yu Shengnan , Zhang Lei , Dong Hao , Gong Jinlong
Published: April 2017

Due to the scarcity of Pt, it is highly desirable to construct core‐shell structures with ultrathin Pt shells while maintaining their high electrocatalytic activities. However, it is necessary to preferentially synthesize a core with a specific structure before further formation of core‐shell catalysts with specific morphologies. This prerequisite greatly increases the complexity of the synthesis process. This article describes a synthetic method of core‐shell Pd@Pt octahedra catalysts from Pd nanocubes, truncated nanocubes or truncated octahedra. The formation of octahedral core‐shell structures involves two key factors: (1) the oxidative etching process of Pd atoms at the corner sites; (2) the different reduction rates between Pt and Pd precursors. This mechanism can be extended to synthesize carbon‐supported sub‐8 nm Pd@Pt octahedra from commercial Pd/C catalysts. The derived carbon‐supported Pd@Pt octahedra catalysts performed comparable activity and durability for methanol oxidation reaction with state‐of‐art PtRu/C catalysts. This synthetic method provides an innovative path for large‐scale production of well‐controlled catalysts. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2528–2534, 2017
Numerical prediction of a nusselt number equation for stirred tanks with helical coils
Authors: Prada Ronald Jaimes , Nunhez José Roberto
Published: April 2017

A methodology to obtain a Nusselt correlation for stirred tank reactors is presented. The novelty of the approach is the use of a validated computational model to obtain the heat‐transfer coefficients. The advantages of this new approach are many, including the possibility of testing different heat‐transfer configurations to obtain their Nusselt correlation without performing experimental runs. Physical phenomena involved was represented both qualitatively and quantitatively. The classical experimental work of (Oldshue and Gretton, Chem Eng Prog. 1954;50(12):615–621) illustrates the procedure. A sufficient number of virtual points in the whole range of the Reynolds number should be obtained. Results strongly depend on mesh refinement in the boundary layer, so a procedure is suggested to guarantee heat‐transfer coefficients are accurately estimated. The final Nusselt correlation was compared against all the 107 experimental points of the work by (Oldshue and Gretton, Chem Eng Prog. 1954;50(12):615–621), and an average deviation on the results of 10.7%. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3912–3924, 2017
Conditional random slope: A new approach for estimating individual child growth velocity in epidemiological research
Authors: Leung Michael , Bassani Diego G. , Racine‐Poon Amy , Goldenberg Anna , Ali Syed Asad , Kang Gagandeep , Premkumar Prasanna S. , Roth Daniel E.
Published: April 2017

Objectives

Conditioning child growth measures on baseline accounts for regression to the mean (RTM). Here, we present the “conditional random slope” (CRS) model, based on a linear‐mixed effects model that incorporates a baseline‐time interaction term that can accommodate multiple data points for a child while also directly accounting for RTM.

METHODS

In two birth cohorts, we applied five approaches to estimate child growth velocities from 0 to 12 months to assess the effect of increasing data density (number of measures per child) on the magnitude of RTM of unconditional estimates, and the correlation and concordance between the CRS and four alternative metrics. Further, we demonstrated the differential effect of the choice of velocity metric on the magnitude of the association between infant growth and stunting at 2 years.

RESULTS

RTM was minimally attenuated by increasing data density for unconditional growth modeling approaches. CRS and classical conditional models gave nearly identical estimates with two measures per child. Compared to the CRS estimates, unconditional metrics had moderate correlation (r = 0.65–0.91), but poor agreement in the classification of infants with relatively slow growth (kappa = 0.38–0.78). Estimates of the velocity‐stunting association were the same for CRS and classical conditional models but differed substantially between conditional versus unconditional metrics.

CONCLUSION

The CRS can leverage the flexibility of linear mixed models while addressing RTM in longitudinal analyses.
Feeding behavior and activity budget of the southern yellow‐cheeked crested gibbons (Nomascus gabriellae) in a lowland tropical forest
Authors: Bach Thanh H. , Chen Jin , Hoang Minh D. , Beng Kingsly C. , Nguyen Van T.
Published: April 2017

The southern yellow‐cheeked crested gibbon (Nomascus gabriellae), an endangered species native to Vietnam and Cambodia, lives exclusively in undisturbed tropical forests and depends primarily on ripe fruit for food. Although this species is highly threatened, its ecology and conservation status remain relatively unknown. In order to understand how this heavily frugivorous primate adapts to the seasonal fluctuation of fruit resources in the forest, we collected feeding behavior and ranging activity data on one group of southern yellow‐cheeked crested gibbons in Cat Tien National Park, Vietnam, over 1‐year period. We compared these data to information on phenological patterns at the site gleaned during a prior study. We found that the gibbons gathered most of their food from 69 different plant species and also consumed insects and bird eggs. Fruits were the main dietary item (43.3%), followed by leaves (38.4%), flowers (11.6%), and other plant parts (6.0%). A significant seasonal shift in diet was observed; fruit generally dominated the diet in the rainy season and leaves in the dry season. The gibbons often started daily activities very early (05:10 am) in the morning and also ended quite early (16:45 pm) in the afternoon. Socializing was concentrated in the early morning, feeding had a bimodal pattern of high activity levels in mid‐morning and mid‐afternoon, and resting was most intense at the earliest and latest hours of the day and at midday, with proportionally less time used for traveling at these times. Averaged over the annual cycle, the gibbons spent 45% of their time feeding, 31.9% resting, 14.1% traveling, and 9.0% socializing. The percentage of time allocated to different activities varied significantly across months and between the dry and rainy seasons. Monthly variation in the activity budget was strongly related to changes in diet. In the rainy season, when the gibbons ate a higher percentage of fruit, they decreased their feeding time, while increasing traveling time in search of food; conversely, in the dry season, when they fed on a higher percentage of leaves, they decreased traveling time. Overall, our results show that the activity budget and diet of the southern yellow‐cheeked crested gibbon are associated with seasonal shifts in climate. This study provides information relevant to the conservation and management of this endangered species by identifying important habitat conditions for reintroducing captive animals into the wild and providing insight into dietary needs, which may be relevant to the maintenance of animals in rescue centers.
Stuck in fragments: Population genetics of the Endangered collared brown lemurEulemur collarisin the Malagasy littoral forest
Authors: Bertoncini Stefania , D'Ercole Jacopo , Brisighelli Francesca , Ramanamanjato Jean‐Baptiste , Capelli Cristian , Tofanelli Sergio , Donati Giuseppe
Published: April 2017

Objectives

The Endangered collared brown lemur (Eulemur collaris) is the largest primate living in the littoral forest of southeastern Madagascar, a top priority habitat for biodiversity conservation on the island. Because this lemur is a key seed‐disperser, an evaluation of the structure and connectivity of the populations surviving in the forest fragments is urgently needed to guide conservation plans.

Materials and Methods

Genetic variability at autosomal microsatellites and mitochondrial DNA was investigated in a total of 49 collared brown lemurs sampled by non‐invasive methods in three littoral forest fragments and in the nearby lowland humid forest.

Results

The overall genetic diversity ofE. collarisin the southeastern coastal region of Madagascar was lower than in other populations, as well as in other lemur species. The population appears highly structured, with less variable and more inbred groups inhabiting the littoral forest fragments compared to the inland area. Major barriers to gene flow were identified isolating littoral forest fragments from each other and from the inland lowland humid forest.

Discussion

Medium to long‐term drift and scarce gene flow is the scenario that best explains the current genetic distribution. Habitat discontinuities such as rivers and grassland between forest fragments played a major role in structuring the population. A common history of size contraction is pointed out by several genetic estimators, indicating a possible ecological crisis triggered around 1,300 years ago. The adoption of strategies aimed at facilitating gene flow and population growth appears crucial to delay further loss of genetic diversity.
Enantioselective Silver and Amine Co‐catalyzed Desymmetrizing Cycloisomerization of Alkyne‐Linked Cyclohexanones
Authors: Manzano Rubén , Datta Swarup , Paton Robert S. , Dixon Darren J.
Published: April 2017

A silver(I) and amine co‐catalyzed desymmetrization of 4‐propargylamino cyclohexanones for the direct enantioselective synthesis of 2‐azabicyclo[3.3.1]nonanes is described. Exploiting reactivity arising from dual activation of the pendant terminal alkyne by silver(I) and the ketone moiety through transient enamine formation, this synthetically relevant transformation is easy to perform, efficient and broad in scope. High enantioselectivity (up to 96 % ee) was achieved by exploiting a significant matching effect between the chirality of a cinchona alkaloid‐derived aminophosphine ligand for the silver(I) salt and the 2‐bis(aryl)methylpyrrolidine catalyst which was rationalized by DFT calculations. This allowed for the preparation of both enantiomers of the bicyclic product with near‐identical stereocontrol.
Cleavage of a P=P Double Bond Mediated by N‐Heterocyclic Carbenes
Authors: Hayakawa Naoki , Sadamori Kazuya , Tsujimoto Shota , Hatanaka Miho , Wakabayashi Tomonari , Matsuo Tsukasa
Published: April 2017

The reaction of the bulky diphosphenes (Rind)P=P(Rind) (1; Rind=1,1,3,3,5,5,7,7‐octa‐R‐substituted s‐hydrindacen‐4‐yl) with two molecules of N‐heterocyclic carbene (NHC; 1,3,4,5‐tetramethylimidazol‐2‐ylidene) resulted in the quantitative formation of the NHC‐bound phosphinidenes NHC→P(Rind) (2), along with the cleavage of the P=P double bond. The reaction times are dependent on the steric size of the Rind groups (11 days for 2 a (R=Et) and 2 h for 2 b (R=Et, Me) at room temperature). The mechanism for the double bond‐breaking is proposed to proceed via the formation of the NHC‐coordinated, highly polarized diphospehenes 3 as an intermediate. Approach of a second NHC to 3 induces P−P bond cleavage and P−C bond formation, which proceeds through a transition state with a large negative Gibbs energy change to afford the two molecules of 2, thus being the rate‐determining step of the overall reaction with the activation barriers of 80.4 for 2 a and 29.1 kJ mol−1 for 2 b.
Layered Double Hydroxide Nanosheets with Multiple Vacancies Obtained by Dry Exfoliation as Highly Efficient Oxygen Evolution Electrocatalysts
Authors: Wang Yanyong , Zhang Yiqiong , Liu Zhijuan , Xie Chao , Feng Shi , Liu Dongdong , Shao Mingfei , Wang Shuangyin
Published: April 2017

Layered double hydroxides (LDHs) with two‐dimensional lamellar structures show excellent electrocatalytic properties. However, the catalytic activity of LDHs needs to be further improved as the large lateral size and thickness of the bulk material limit the number of exposed active sites. However, the development of efficient strategies to exfoliate bulk LDHs into stable monolayer LDH nanosheets with more exposed active sites is very challenging. On the other hand, the intrinsic activity of monolayer LDH nanosheets can be tuned by surface engineering. Herein, we have exfoliated bulk CoFe LDHs into ultrathin LDH nanosheets through Ar plasma etching, which also resulted in the formation of multiple vacancies (including O, Co, and Fe vacancies) in the ultrathin 2D nanosheets. Owing to their ultrathin 2D structure, the LDH nanosheets expose a greater number of active sites, and the multiple vacancies significantly improve the intrinsic activity in the oxygen evolution reaction (OER).
The Dynamics of the Reaction of FeO+ and H2: A Model for Inorganic Oxidation
Authors: Essafi Stéphanie , Tew David P. , Harvey Jeremy N.
Published: April 2017

Extensive density functional theory (DFT) calculations using the B3LYP functional were used to explore the sextet and quartet energy potential energy surfaces (PESs) of the title reaction, and as a basis to fit global analytical reactive PESs. Surface‐hopping dynamics on these PESs reproduce the experimentally observed reactivity and confirm that hydrogen activation rather than spin‐state change is rate‐limiting at low reaction energy, where the main products are Fe+ and H2O. A change in spin state is inefficient in the product region so that excited‐state 4Fe+ is the dominant product. At higher energies, spin‐allowed hydrogen atom abstraction to form FeOH+ predominates. At intermediate energy, a previously unexpected rebound mechanism contributes significantly to the reactivity.
Base‐Controlled Completely Selective Linear or Branched Rhodium(I)‐Catalyzed C−H ortho‐Alkylation of Azines without Preactivation
Authors: Tran Gaël , Hesp Kevin D. , Mascitti Vincent , Ellman Jonathan A.
Published: April 2017

A [RhI]/bisphosphine/base catalytic system for the ortho‐selective C−H alkylation of azines by acrylates and acrylamides is reported. This catalytic system features an unprecedented complete linear or branched selectivity that is solely dependent on the catalytic base that is used. Complete branched selectivity is even achieved for ethyl methacrylate, which enables the introduction of a quaternary carbon center. Excellent functional group compatibility is demonstrated for both linear and branched alkylations. The operational simplicity and broad scope of this transformation allow for rapid access to functionalized azines of direct pharmaceutical and agrochemical relevance.
Global Mapping of Protein–Lipid Interactions by Using Modified Choline‐Containing Phospholipids Metabolically Synthesized in Live Cells
Authors: Wang Danyang , Du Shubo , Cazenave‐Gassiot Amaury , Ge Jingyan , Lee Jun‐Seok , Wenk Markus R. , Yao Shao Q.
Published: April 2017

The protein–lipid interaction is an essential metabolic process that mediates cellular signaling and functions. Existing strategies for large‐scale mapping studies of the protein–lipid interaction fall short in their incompatibility with metabolic incorporation or inability to remove unwanted interferences from lipidated proteins. By incorporating an alkyne‐containing choline head group and a diazirine‐modified fatty acid simultaneously into choline‐containing phospholipids synthesized from live mammalian cells, protein–phospholipid interactions have been successfully imaged in live cells. Subsequent in situ profiling of the modified Cho phospholipid‐crosslinked proteins followed by quantitative proteomics allowed identification of several hundred putative phospholipid‐interacting proteins, some of which were further validated.
N‐Heterocyclic Carbene Catalyzed [4+2] Annulation of Enals via a Double Vinylogous Michael Addition: Asymmetric Synthesis of 3,5‐Diaryl Cyclohexenones
Authors: Chen Xiang‐Yu , Liu Qiang , Chauhan Pankaj , Li Sun , Peuronen Anssi , Rissanen Kari , Jafari Ehsan , Enders Dieter
Published: April 2017

A strategy for the N‐heterocyclic carbene (NHC) catalyzed asymmetric synthesis of 3,5‐diaryl substituted cyclohexenones has been developed via oxidative [4+2] annulation of enals and alkenylisoxazoles. It is the first example of using NHC organocatalysis in a double vinylogous Michael type reaction, a challenging but highly desirable topic. This unprecedented protocol affords good yields as well as high to excellent diastereo‐ and enantioselectivities.
Poly‐cytosine DNA as a High‐Affinity Ligand for Inorganic Nanomaterials
Authors: Lu Chang , Huang Zhicheng , Liu Biwu , Liu Yibo , Ying Yibin , Liu Juewen
Published: April 2017

Attaching DNA to nanomaterials is the basis for DNA‐directed assembly, sensing, and drug delivery using such hybrid materials. Poly‐cytosine (poly‐C) DNA is a high affinity ligand for four types of commonly used nanomaterials, including nanocarbons (graphene oxide and single‐walled carbon nanotubes), transition metal dichalcogenides (MoS2 and WS2), metal oxides (Fe3O4 and ZnO), and metal nanoparticles (Au and Ag). Compared to other homo‐DNA sequences, poly‐C DNA has the highest affinity for the first three types of materials. Using a diblock DNA containing a poly‐C block to attach to surfaces, the target DNA was successfully hybridized to the other block on graphene oxide more efficiently than that containing a typical poly‐A block, especially in the presence of non‐specific background DNA, proteins, or surfactants. This work provides a simple solution for functionalizing nanomaterials with non‐modified DNA and offers new insights into DNA biointerfaces.
Microporous Polyamide Membranes for Molecular Sieving of Nitrogen from Volatile Organic Compounds
Authors: Zhou Haoli , Tao Fei , Liu Quan , Zong Chunxin , Yang Wenchao , Cao Xingzhong , Jin Wanqin , Xu Nanping
Published: April 2017

Microporous polymer membranes continue to receive tremendous attention for energy‐efficient gas separation processes owing to their high separation performances. A new network microporous polyamide membrane with good molecular‐sieving performance for the separation of N2 from a volatile organic compound (VOC) mixture is described. Triple‐substituted triptycene was used as the main monomer to form a fisherman's net‐shaped polymer, which readily forms a composite membrane by solution casting. This membrane exhibited outstanding separation performance and good stability for the molecular‐sieving separation of N2 over VOCs such as cyclohexane. The rejection rate of the membrane reached 99.2 % with 2098 Barrer N2 permeability at 24 °C under 4 kPa. This approach promotes development of microporous membranes for separation of condensable gases.
Non‐Pincer‐Type Manganese Complexes as Efficient Catalysts for the Hydrogenation of Esters
Authors: van Putten Robbert , Uslamin Evgeny A. , Garbe Marcel , Liu Chong , Gonzalez‐de‐Castro Angela , Lutz Martin , Junge Kathrin , Hensen Emiel J. M. , Beller Matthias , Lefort Laurent , Pidko Evgeny A.
Published: April 2017

Catalytic hydrogenation of carboxylic acid esters is essential for the green production of pharmaceuticals, fragrances, and fine chemicals. Herein, we report the efficient hydrogenation of esters with manganese catalysts based on simple bidentate aminophosphine ligands. Monoligated Mn PN complexes are particularly active for the conversion of esters into the corresponding alcohols at Mn concentrations as low as 0.2 mol % in the presence of sub‐stoichiometric amounts of KOtBu base.
Metal‐Free Formal Oxidative C−C Coupling by In Situ Generation of an Enolonium Species
Authors: Kaiser Daniel , de la Torre Aurélien , Shaaban Saad , Maulide Nuno
Published: April 2017

Much contemporary organic synthesis relies on transformations that are driven by the intrinsic, so‐called “natural”, polarity of chemical bonds and reactive centers. The design of unconventionally polarized synthons is a highly desirable strategy, as it generally enables unprecedented retrosynthetic disconnections for the synthesis of complex substances. Whereas the umpolung of carbonyl centers is a well‐known strategy, polarity reversal at the α‐position of a carbonyl group is much rarer. Herein, we report the design of a novel electrophilic enolonium species and its application in efficient and chemoselective, metal‐free oxidative C−C coupling.
Photoelectroreduction of Building‐Block Chemicals
Authors: Chen Fengjiao , Cui Wei , Zhang Jie , Wang Yeyun , Zhou Junhua , Hu Yongpan , Li Yanguang , Lee Shuit‐Tong
Published: April 2017

Conventional photoelectrochemical cells utilize solar energy to drive the chemical conversion of water or CO2 into useful chemical fuels. Such processes are confronted with general challenges, including the low intrinsic activities and inconvenient storage and transportation of their gaseous products. A photoelectrochemical approach is proposed to drive the reductive production of industrial building‐block chemicals and demonstrate that succinic acid and glyoxylic acid can be readily synthesized on Si nanowire array photocathodes free of any cocatalyst and at room temperature. These photocathodes exhibit a positive onset potential, large saturation photocurrent density, high reaction selectivity, and excellent operation durability. They capitalize on the large photovoltage generated from the semiconductor/electrolyte junction to partially offset the required external bias, and thereby make this photoelectrosynthetic approach significantly more sustainable compared to traditional electrosynthesis.
Palladium‐Catalyzed Carbonylation of sec‐ and tert‐Alcohols
Authors: Dong Kaiwu , Sang Rui , Liu Jie , Razzaq Rauf , Franke Robert , Jackstell Ralf , Beller Matthias
Published: April 2017

A general palladium‐catalyzed synthesis of linear esters directly from sec‐ and tert‐alcohols is described. Compared to the classic Koch–Haaf reaction, which leads to branched products, this new transformation gives the corresponding linear esters in high yields and selectivity. Key for this protocol is the use of an advanced palladium catalyst system with L2 (pytbpx) as the ligand. A variety of aliphatic and benzylic alcohols can be directly used and the catalyst efficiency for the benchmark reaction is outstanding (turnover number up to 89 000).
Total Synthesis of (−)‐Albocycline
Authors: Chatare Vijay K. , Andrade Rodrigo B.
Published: April 2017

The macrolactone natural product (−)‐albocycline is a promising antibiotic candidate for the treatment of both methicillin resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant strains. Herein we report a concise total synthesis of (−)‐albocycline in 14 steps from commercially available methyl (R)‐3‐hydroxybutyrate. Novel key steps include the highly regio‐ and stereoselective reactions of chiral N‐sulfinyl metallodienamines (NSMDs) with aldehydes and the Davis oxaziridine, in addition to the Horner–Wadsworth–Emmons olefination of N‐sulfinyl imines.
Formation of Silver Nanoparticles by Electron Transfer in Peptides and c‐Cytochromes
Authors: Vasylevskyi Serhii I. , Kracht Sonja , Corcosa Paula , Fromm Katharina M. , Giese Bernd , Füeg Michael
Published: April 2017

The reduction of Ag+ ions to Ag0 atoms is a highly endergonic reaction step, only the aggregation to Agn clusters leads to an exergonic process. These elementary chemical reactions play a decisive role if Ag nanoparticles (AgNPs) are generated by electron transfer (ET) reactions to Ag+ ions. We studied the formation of AgNPs in peptides by photoinduced ET, and in c‐cytochromes by ET from their Fe2+/hemes. Our earlier photoinduced experiments in peptides had demonstrated that histidine prevents AgNP formation. We have now observed that AgNPs can be easily synthesized with less‐efficient Ag+‐binding amino acids, and the rate increases in the order lysine<asparagine<aspartate<serine. The ability of Fe2+/hemes of c‐cytochromes to reduce Ag+ to AgNPs was studied in an enzymatic experiment and with living bacteria Geobacter sulfurreducens (Gs).
Geometric stability of PtFe/PdFe embedded in graphene and catalytic activity for CO oxidation
Authors: Rui Wang , Wei Feng , Dandan Zhang , Huiling Liu , Huanyu Zhao , Xuri Huang
Published: April 2017

The direct methanol fuel cell (DMFC) is considered as a promising power source, because of its abundant fuel source, high energy density and environmental friendliness. Among DMFC anode materials, Pt and Pt group metals are considered to be the best electrocatalysts. The combination of Pt with some specific transition metal can reduce the cost and improve the tolerance toward CO poisoning of pure Pt catalysts. In this paper, the geometric stabilities of PtFe/PdFe atoms anchored in graphene sheet and catalytic CO oxidation properties were investigated using the density functional theory method. The results show that the Pt (Pd) and Fe atoms can replace C atoms in graphene sheet. The CO oxidation reaction by molecular O2 on PtFe–graphene and PdFe–graphene was studied. The results show that the Eley–Rideal (ER) mechanism is expected over the Langmuir–Hinshelwood mechanism for CO oxidation on both PtFe–graphene and PdFe–graphene. Further, complete CO oxidation on PtFe–graphene and PdFe–graphene proceeds via a two‐step ER reaction: CO(gas) + O2(ads) → CO2(ads) + O(ads) and CO(gas) + O(ads) → CO2(ads). Our results reveal that PtFe/PdFe commonly embedded in graphene can be used as a catalyst for CO oxidation. The microscopic mechanism of the CO oxidation reaction on the atomic catalysts was explored.
Synthesis, characterization and application of nano‐CoAl2O4 as an efficient catalyst in the preparation of hexahydroquinolines
Authors: Khazaei Ardeshir , Jafari‐Ghalebabakhani Leila , Ghaderi Esmaeil , Tavasoli Mahsa , Moosavi‐Zare Ahmad Reza
Published: April 2017

In this work, nano‐CoAl2O4 was prepared and characterized by FT‐IR, energy dispersive X‐ray analysis (EDX), X‐ray diffraction patterns (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM) and transmission electron microscopy (TEM). Nano‐CoAl2O4 was applied for the synthesis of hexahydroquinoline derivatives by the condensation reaction between ethyl acetoacetate, dimedone and various aldehydes. These reactions were carried out at 80 °C under solvent‐free conditions.
Green synthesis of Ni‐Cu‐Zn ferrite nanoparticles using tragacanth gum and their use as an efficient catalyst for the synthesis of polyhydroquinoline derivatives
Authors: Taghavi Fardood Saeid , Ramazani Ali , Golfar Zahra , Joo Sang Woo
Published: April 2017

Ni0.35Cu0.25Zn0.4Fe2O4 MNPs were synthesized using tragacanth gum as biotemplate and Metals nitrate as the metal source by the sol–gel method. The sample was characterized by powder X‐ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM) and energy dispersive X‐ray analysis (EDX). The nanoparticles exhibit ferromagnetic behaviour at room temperature, with a saturation magnetization of 52.76 emu/g and a coercivity of 80.14 Oe. Thereupon, Ni‐Cu‐Zn ferrite nanoparticles as an efficient catalyst was used for the synthesis of polyhydroquinoline derivatives via multi‐component reactions under microwave irradiation. Simple work‐up, mild reaction conditions, short reaction times, use of an economically convenient catalyst, and excellent product yields are the advantageous features of this method. The catalyst could easily be recycled and reused few times without noticeable decrease in catalytic activity.
Mechanical enhancement of zirconia reinforced polyimine nanocomposites
Authors: Zhang Si , Lv Yanting , Li Jiayi , Liang Song , Liu Zhenning
Published: April 2017

Polymeric nanocomposites have demonstrated superior performance in recent decades, combining the advantages of polymer and nanoparticle fillers. However, nanocomposites of polyimine, a neoteric thermoset material, have been rarely investigated. Herein, a series of polyimine nanocomposites reinforced by zirconia (ZrO2) have been fabricated by heat‐pressing under mild conditions. The resultant polyimine nanocomposites show significant enhancements on multiple mechanical properties including tensile strength, toughness, bending strength, and impact strength, whereas the optimal amount of ZrO2 particles for the best performance of a specific property varies. Interestingly, the tensile strength and toughness of the polyimine nanocomposites can be simultaneously increased by 40% and 85%, indicating that the nanocomposites exhibit excellent integration of tensile strength and toughness analogous to natural materials. Hence, a facile and cost‐effective approach to enhance mechanical properties of polyimine has been realized for more applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45183.
Poly(4‐vinylphenol)/tetra‐n‐butylammonium iodide: Efficient organocatalytic system for synthesis of cyclic carbonates from CO2 and epoxides
Authors: Wang Xiangyong , Zhao Yingying , Kodama Koichi , Hirose Takuji
Published: April 2017

An efficient polymer‐based catalytic system of poly(4‐vinylphenol) and tetra‐n‐butylammonium iodide was developed for the synthesis of cyclic carbonates from epoxides and CO2. Owing to the synergistic effects of hydroxyl groups and iodide anions, this commercially available and metal‐free system was highly active for the reaction of various terminal epoxides under environmentally benign conditions, at 25 to 60 °C and atmospheric pressure of CO2, without the use of any organic solvents. The catalyst system can be easily separated by adding ether, and its ability was recovered by treating it with 40% CH3CO2H aq. The recyclability was investigated in detail for three substrates, epichlorohydrin, 1,2‐epoxyhexane, and styrene oxide, using 1H nuclear magnetic resonance analysis. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45189.
Synthesis and Evaluation of Thiazolidine Amide and N‐Thiazolyl Amide Fluoroquinolone Derivatives
Authors: Garza Isaac , Wallace Miranda J. , Fernando Dinesh , Singh Aman , Lee Richard E. , Gerding Jason S. , Franklin Cynthia , Yendapally Raghunandan
Published: April 2017

In an effort to develop new fluoroquinolones, we synthesized eight compounds and tested them against a panel of bacteria. The design of these compounds was guided by the introduction of the isothiazoloquinolone motif. The three most active compounds in this series, 8–10, demonstrated good antibacterial activity against methicillin‐sensitive Staphylococcus aureus and healthcare‐acquired methicillin‐resistant Staphylococcus aureus (MIC 0.62–6.3 µg/mL). Further, when these three active compounds were tested for their inhibitory effects on bacterial enzymes, compound 9 was the most effective agent exhibiting IC50 values of 33.9 and 116.5 μM in the S. aureus deoxyribonucleic acid (DNA) gyrase supercoiling and topoisomerase IV decatenation assays, respectively.
A personal connection: Promoting positive attitudes towards teaching and learning
Authors: Lujan Heidi L. , DiCarlo Stephen E.
Published: April 2017

Students' attitudes towards teaching and learning must be addressed with the same seriousness and effort as we address content. Establishing a personal connection and addressing our students' basic psychological needs will produce positive attitudes towards teaching and learning and develop life‐long learners. It will also promote constructive student‐teacher relationships that have a profound influence on our students' approach towards school. To begin this process, consider the major tenets of the Self‐Determination Theory. The Self‐Determination Theory of human motivation focuses on our students' innate psychological needs and the degree to which an individual's behavior is self‐motivated and self‐determined. Faculty can satisfy the innate psychological needs by addressing our students' desire for relatedness, competence and autonomy. Relatedness refers to our students' need to feel connected to others, to be a member of a group, to have a sense of communion and to develop close relationships with others. Competence is believing our students can succeed, challenging them to do so and imparting that belief in them. Autonomy involves considering the perspectives of the student and providing relevant information and opportunities for student choice and initiating and regulating their own behaviors. Establishing a personal connection and addressing our students' basic psychological needs will improve our teaching, inspire and engage our students and promote positive attitudes towards teaching and learning while reducing competition and increasing compassion. These are important goals because unless students are inspired and motivated and have positive attitudes towards teaching and learning our efforts will fail to meet their full potential. Anat Sci Educ 10: 503–507. © 2017 American Association of Anatomists.
Adaptive Backstepping Control of Six‐Phase PMSM Using Functional Link Radial Basis Function Network Uncertainty Observer
Authors: Lin Faa‐Jeng , Chen Shih‐Gang , Sun I‐Fan
Published: April 2017

An adaptive backstepping control (ABSC) using a functional link radial basis function network (FLRBFN) uncertainty observer is proposed in this study to construct a high‐performance six‐phase permanent magnet synchronous motor (PMSM) position servo drive system. The dynamic model of a field‐oriented six‐phase PMSM position servo drive is described first. Then, a backstepping control (BSC) system is designed for the tracking of the position reference. Since the lumped uncertainty of the six‐phase PMSM position servo drive system is difficult to obtain in advance, it is very difficult to design an effective BSC for practical applications. Therefore, an ABSC system is designed using an adaptive law to estimate the required lumped uncertainty in the BSC system. To further increase the robustness of the six‐phase PMSM position servo drive, an FLRBFN uncertainty observer is proposed to estimate the lumped uncertainty of the position servo drive. In addition, an online learning algorithm is derived using Lyapunov stability theorem to learn the parameters of the FLRBFN online. Finally, the proposed position control system is implemented in a 32‐bit floating‐point DSP, TMS320F28335. The effectiveness and robustness of the proposed intelligent ABSC system are verified by some experimental results.
Theoretical insights into the effect of pH values on oxidation processes in the emission of firefly luciferin in aqueous solution
Authors: Hiyama Miyabi , Akiyama Hidefumi , Koga Nobuaki
Published: April 2017

To elucidate the emission process of firefly d‐luciferin oxidation across the pH range of 7–9, we identified the emission process by comparison of the potential and free‐energy profiles for the formation of the firefly substrate and emitter, including intermediate molecules such as d‐luciferyl adenylate, 4‐membered dioxetanone, and their deprotonated chemical species. From these relative free energies, it is observed that the oxidation pathway changes from d‐luciferin → deprotonated d‐luciferyl adenylate → deprotonated 4‐membered dioxetanone → oxyluciferin to deprotonated d‐luciferin → deprotonated d‐luciferyl adenylate → deprotonated 4‐membered dioxetanone → oxyluciferin with increasing pH value. This indicates that deprotonation on 6′OH occurs during the formation of dioxetanone at pH 7–8, whereas luciferin in the reactant has a 6′OH‐deprotonated form at pH 9.
Targeting Conformational Activation of CDK2 Kinase
Authors: Pellerano Morgan , Tcherniuk Sergey , Perals Corine , Ngoc Van Thi Nhu , Garcin Elsa , Mahuteau‐Betzer Florence , Teulade‐Fichou Marie‐Paule , Morris May C.
Published: April 2017

Cyclin‐dependent kinases constitute attractive pharmacological targets for cancer therapeutics, yet inhibitors in clinical trials target the ATP‐binding pocket of the CDK and therefore suffer from limited selectivity and emergence of resistance. The more recent development of allosteric inhibitors targeting conformational plasticity of protein kinases offers promising perspectives for therapeutics. In particular tampering with T‐loop dynamics of CDK2 kinase would provide a selective means of inhibiting this kinase, by preventing its conformational activation. To this aim we engineered a fluorescent biosensor that specifically reports on conformational changes of CDK2 activation loop and is insensitive to ATP or ATP‐competitive inhibitors, which constitutes a highly sensitive probe for identification of selective T‐loop modulators. This biosensor was successfully applied to screen a library of small chemical compounds leading to discovery of a family of quinacridine analogs, which potently inhibit cancer cell proliferation, and promote accumulation of cells in S phase and G2. These compounds bind CDK2/ Cyclin A, inhibit its kinase activity, compete with substrate binding, but not with ATP, and dock onto the T‐loop of CDK2. The best compound also binds CDK4 and CDK4/Cyclin D1, but not CDK1. The strategy we describe opens new doors for the discovery of a new class of allosteric CDK inhibitors for cancer therapeutics.
Carboxymethyl β‐cyclodextrin as chiral selector in capillary electrophoresis: Enantioseparation of 16 basic chiral drugs and its chiral recognition mechanism associated with drugs' structural features
Authors: Fang Linlin , Du Yueying , Hu Xiaoyu , Luo Linda , Guo Xin , Guo Xingjie , Yu Jia
Published: April 2017

Herein we present the enantioseparation of 10 cardiovascular agents and six bronchiectasis drugs including propranolol, carteolol, metoprolol, atenolol, pindolol, esmolol, bisoprolol, bevantolol, arotinolol, sotalol, clenbuterol, procaterol, bambuterol, tranterol, salbutamol and terbutaline sulfate using carboxymethyl‐β‐cyclodextrin (CM‐β‐CD) as chiral selector. To our knowledge, there is no literature about using CM‐β‐CD for separating carteolol, esmolol, bisoprolol, bevantolol, arotinolol, procaterol, bambuterol and tranterol. During the course of work, changes in pH, CM‐β‐CD concentration, buffer type and concentration were studied in relation to chiral resolution. Excellent enantiomeric separations were obtained for all 16 compounds, especially for procaterol. An impressive resolution value, up to 17.10, was obtained. In particular, most of them achieved rapid separations within 20 min. Given the fact that enantioseparation results rely on analytes' structural characters, the possible separation mechanisms were discussed. In addition, in order to obtain faster separation for propranolol enantiomers in practical application, the effective length of capillary was innovatively shortened from 45 to 30 cm. After the validation, the method was successfully applied to the enantiomeric purity determination of propranolol in the formulation of drug substances.
Swallowing safety in Parkinson's disease after zona incerta deep brain stimulation
Authors: Sundstedt Stina , Holmén Lina , Rova Elin , Linder Jan , Nordh Erik , Olofsson Katarina
Published: April 2017

Objectives

The objective of this study was to examine swallowing function in patients with Parkinson's disease before and after caudal zona incerta deep brain (cZI DBS) surgery. The aims were to examine the effect of cZI DBS on swallowing safety regarding liquid and solid food, as well as to identify the effect of cZI DBS on body mass index (BMI) and specific items from part II of the Unified Parkinson's Disease Rating Scale (UPDRS).

Materials and Methods

The median age of the 14 patients was 57 years (range 46–71), with a median disease duration of 6 years (range 2–13). The present sample is an extension of a previous report, into which six additional patients have been added. Fiber endoscopic examinations of swallowing function, measures of BMI, and evaluation of UPDRS part II items were made before and 12 months after surgery, with and without activated DBS.

Results

There were no significant changes due to cZI DBS regarding penetration/aspiration, pharyngeal residue or premature spillage (p > .05). Median BMI increased by +1.1 kg/m2 12 months after surgery (p = .01, r = .50). All reported specific symptoms from the UPDRS part II were slight or mild. A significant improvement regarding handling of utensils was seen 12 months postoperatively (p = .03, r = −.42).

Conclusions

Caudal zona incerta DBS was found not to have a negative impact on swallowing safety. A significant increase in postoperative weight was observed, and speech seemed to be slightly negatively affected, whereas handling of utensils was improved with cZI DBS.
Patient Characteristics and Outcomes Related to Successful Outpatient Competency Restoration
Authors: Mikolajewski Amy J. , Manguno‐Mire Gina M. , Coffman Kelly L. , Deland Sarah M. , Thompson John W.
Published: April 2017

Criminal defendants have a fundamental right to a fair and speedy trial. However, individuals found incompetent to stand trial are unable to move forward in the adjudication process and are often mired in protracted legal proceedings. If competency restoration is statutorily permissible and can be conducted in the outpatient setting, we propose that it should be considered based on burgeoning empirical data. We present data from an outpatient forensic clinic in which individuals are conditionally released to receive competency restoration in the community. Results indicated that three variables, including being single/never married, having comorbid intellectual disability and mental illness, and having one's conditional release revoked, were negatively related to successful restoration. The final model explained approximately one‐third of the variance in restorability and correctly classified 75% of cases. Results demonstrate that individuals can be safely released to the community and successfully restored to competency in the outpatient setting. Utilizing outpatient competency restoration would not only reduce strain on inpatient facilities, but would also reduce the cost of treatment. Copyright © 2017 John Wiley & Sons, Ltd.
Constructive approach for smoke plume animation using turbulent toroidal vortices
Authors: Khorloo Oyundolgor , Altantsetseg Enkhbayar
Published: April 2017

In this paper, we propose an efficient approach for generating plausible smoke animation at interactive rates. Among a wide range of smoke animation approaches, our proposed approach simulates the behavior of gaseous phenomena such as turbulent smoke from a steam locomotive. Our method uses existing techniques for simulating smoke animation based on a particle system and extends them by introducing a simple yet efficient toroidal vortex to describe a more complex and turbulent behavior. The key idea is that vortex flows generated by torus‐type smoke primitives are passively advected in a wind field to describe the turbulent flow of smoke.
Structure‐Based Design of a New Scaffold for Cell‐Penetrating Peptidic Inhibitors of the Histone Demethylase PHF8
Authors: Dorosz Jerzy , Olsen Lars , Seger Signe Teuber , Steinhauer Cornelia , Bouras Giorgos , Helgstrand Charlotte , Wiuf Anders , Gajhede Michael
Published: April 2017

The histone demethylase PHF8 catalyzes demethylation of mono‐ and di‐methylated Lys9 on histone H3 (H3K9me1/2), and is a transcriptional activator involved in the development and cancer. Affinity and specificity of PHF8 towards H3K9me2 is affected by interaction with both the catalytic domain and a PHD reader domain. The latter specifically recognizes tri‐methylated Ly4 on histone H3. A fragment of the histone H3 tail with tri‐methylated Lys4 was used as a template for the structure‐based design of a cyclic, cell‐penetrating peptide that exhibits micromolar binding affinity to PHF8 in biochemical assays. The inhibitor has significantly lower affinity towards KDM2 enzymes (the phylogenetically closest subfamily), and to KDM3 and KDM6 subfamilies. Selectivity is only marginal towards an enzyme from the KDM4 family, which shares histone tail specificity with PHF8. It is a substrate of KDM5B, thus implying that the free N terminus is not part of the KDM5 enzyme substrate recognition machinery. The cyclic peptide's ability to penetrate cells is achieved by incorporation of a sequence derived from HIV Tat. The derived cyclic peptide can be used as a starting compound in the search for potent and selective PHF8 inhibitors.