bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photophysics of Structurally Modified Flavin Derivatives in the Blue‐Light Photoreceptor YtvA: A Combined Experimental and Theoretical Study
Authors: Silva‐Junior Mario R. , Mansurova Madina , Gärtner Wolfgang , Thiel Walter 
Published: August 2013

AbstractThe light‐induced processes of two flavin mononucleotide derivatives (1‐ and 5‐deaza flavin mononucleotide, 1DFMN and 5DFMN), incorporated into the LOV domain of YtvA protein from Bacillus subtilis, were studied by a combination of experimental and computational methods. Quantum mechanics/molecular mechanics (QM/MM) calculations were carried out in which the QM part was treated by density functional theory (DFT) using the B3LYP functional for geometry optimizations and the DFT/MRCI method for spectroscopic properties, whereas the MM part was described by the CHARMM force field. 1DFMN is incorporated into the protein binding site, yielding a red‐shifted absorption band (λmax=530 nm compared to YtvA wild‐type λmax=445 nm), but does not undergo any LOV‐typical photoreactions such as triplet and photoadduct formation. QM/MM computations confirmed the absence of a channel for triplet formation and located a radiation‐free channel (through an S1/S0 conical intersection) along a hydrogen transfer path that might allow for fast deactivation. By contrast, 5DFMN‐YtvA‐LOV shows a blue‐shifted absorption (λmax=410 nm) and undergoes similar photochemical processes to FMN in the wild‐type protein, both with regard to the photophysics and the formation of a photoadduct with a flavin‐cysteinyl covalent bond. The QM/MM calculations predict a mechanism that involves hydrogen transfer in the T1 state, followed by intersystem crossing and adduct formation in the S0 state for the forward reaction. Experimentally, in contrast to wild‐type YtvA, dark‐state recovery in 5DFMN‐YtvA‐LOV is not thermally driven but can only be accomplished after absorption of a second photon by the photoadduct, again via the triplet state. The QM/MM calculations suggest a photochemical mechanism for dark‐state recovery that is accessible only for the adduct with a C4aS bond but not for alternative adducts with a C5S bond.
2 D Self‐Assembly and Catalytic Homo‐coupling of the Terminal Alkyne 1,4‐Bis(3,5‐diethynyl‐phenyl)butadiyne‐1,3 on Ag(111)
Authors: Cirera Borja , Zhang Yi‐Qi , Klyatskaya Svetlana , Ruben Mario , Klappenberger Florian , Barth Johannes V. 
Published: August 2013

AbstractThe covalent linking of terminal alkynes is a promising approach for the bottom‐up fabrication of novel, carbon‐rich or all‐carbon materials, which was recently extended towards interfacial architectures. Here we report the synthesis of a novel organic species (1,4‐bis(3,5‐diethynylphenyl)butadiyne‐1,3) and employ it to engineer self‐assembled supramolecular layers and covalent networks on the Ag(111) surface. Samples are prepared in‐situ under ultra‐high vacuum conditions and examined at the molecular level with scanning tunneling microscopy. After evaporating the two‐fold symmetric molecule onto the substrate at temperatures below 300 K and subsequent cooling to 5 K we find highly regular supramolecular phases commensurate with the underlying silver surface and stabilized mainly by weak, non‐covalent interactions originating from the terminal ethynyl moieties. Annealing at temperatures between 350 and 500 K triggers catalytic conversions with the pertaining covalent coupling reactions resulting in small aggregates or irregular polymeric networks. Our detailed analysis of the binding motifs demonstrates that two competing reaction pathways dominate the covalent linking processes. The first is the Glaser–Hay‐type homo‐coupling of two alkyne terminations leading to a linear butadiyne bridge. The second is the connection of a butadiyne group to a laterally attacking terminal alkyne, converting the attacked ethyne to ethene moieties, which presents a major obstacle for the production of regular networks.
How Many Molecular Layers of Polar Solvent Molecules Control Chemistry? The Concept of Compensating Dipoles
Authors: Langhals Heinz , Braun Patricia , Dietl Christian , Mayer Peter 
Published: August 2013

AbstractThe extension of the solvent influence of the shell into the volume of a polar medium was examined by means of anti‐collinear dipoles on the basis of the ET(30) solvent polarity scale (i.e., the molar energy of excitation of a pyridinium‐N‐phenolatebetaine dye; generally: ET=28 591 nm kcal mol−1/λmax) where no compensation effects were found. As a consequence, solvent polarity effects are concentrated to a very thin layer of a few thousand picometres around the solute where extensions into the bulk solvent become unimportant. A parallelism to the thin surface layer of water to the gas phase is discussed.
Hydrothermal Synthesis of a Crystalline Rutile TiO2 Nanorod Based Network for Efficient Dye‐Sensitized Solar Cells
Authors: Yu Hua , Pan Jian , Bai Yang , Zong Xu , Li Xinyong , Wang Lianzhou 
Published: August 2013

AbstractOne‐dimensional (1D) TiO2 nanostructures are desirable as photoanodes in dye‐sensitized solar cells (DSSCs) due to their superior electron‐transport capability. However, making use of the DSSC performance of 1D rutile TiO2 photoanodes remains challenging, mainly due to the small surface area and consequently low dye loading. Herein, a new type of photoanode with a three‐dimensional (3D) rutile‐nanorod‐based network structure directly grown on fluorine‐doped tin oxide (FTO) substrates was developed by using a facile two‐step hydrothermal process. The resultant photoanode possesses oriented rutile nanorod arrays for fast electron transport as the bottom layer and radially packed rutile head‐caps with an improved large surface area for efficient dye adsorption. The diffuse reflectance spectra showed that with the radially packed top layer, the light‐harvesting efficiency was increased due to an enhanced light‐scattering effect. A combination of electrochemical impedance spectroscopy (EIS), dark current, and open‐circuit voltage decay (OCVD) analyses confirmed that the electron‐recombiantion rate was reduced on formation of the nanorod‐based 3D network for fast electron transport. As a resut, a light‐to‐electricity conversion efficiency of 6.31 % was achieved with this photoanode in DSSCs, which is comparable to the best DSSC efficiencies that have been reported to date for 1D rutile TiO2.
Preparation and Functions of Hybrid Membranes with Rings of Ag NPs Anchored at the Edges of Highly Ordered Honeycomb‐Patterned Pores
Authors: Dong Renhao , Xu Jiaheng , Yang Zhefei , Wei Guangcheng , Zhao Wenrong , Yan Junlin , Fang Yu , Hao Jingcheng 
Published: August 2013

AbstractWe report a new, simple strategy to apply honeycomb films for the patterning of colloidal particles. By combination of a “bottom‐up” breath figure method and the electrochemical properties of the honeycomb films of ferrocenyl‐based oligomers, highly ordered hybrid membranes coated with ring‐like patterning of 0D‐ and 1D‐Ag nanoparticles (NPs) have been fabricated. One interesting phenomenon is that the nucleation and adsorption of Ag dots occurred preferentially at the edges of the micropores. The hybrid membranes exhibited richly electrochemical activities towards reduction of iodate and enhanced effectively catalytic reduction of organic dyes. We believe that this method can be used to decorate and/or assemble functional metal NPs such as Au, Pd, and Cu on honeycomb‐patterned materials for the further applications of photonics, sensors, and catalysis.
Age‐related neurochemical changes in the rhesus macaque superior olivary complex
Authors: Gray Daniel T. , Engle James R. , Recanzone Gregg H. 
Published: August 2013

ABSTRACTPositive immunoreactivity to the calcium‐binding protein parvalbumin (PV) and nitric oxide synthase NADPH‐diaphorase (NADPHd) is well documented within neurons of the central auditory system of both rodents and primates. These proteins are thought to play roles in the regulation of auditory processing. Studies examining the age‐related changes in expression of these proteins have been conducted primarily in rodents but are sparse in primate models. In the brainstem, the superior olivary complex (SOC) is crucial for the computation of sound source localization in azimuth, and one hallmark of age‐related hearing deficits is a reduced ability to localize sounds. To investigate how these histochemical markers change as a function of age and hearing loss, we studied eight rhesus macaques ranging in age from 12 to 35 years. Auditory brainstem responses (ABRs) were obtained in anesthetized animals for click and tone stimuli. The brainstems of these same animals were then stained for PV and NADPHd reactivity. Reactive neurons in the three nuclei of the SOC were counted, and the densities of each cell type were calculated. We found that PV and NADPHd expression increased with both age and ABR thresholds in the medial superior olive but not in either the medial nucleus of the trapezoid body or the lateral superior olive. Together these results suggest that the changes in protein expression employed by the SOC may compensate for the loss of efficacy of auditory sensitivity in the aged primate. J. Comp. Neurol. 522:573–591, 2014. © 2013 Wiley Periodicals, Inc.
Variable temporoinsular cortex neuroanatomy in primates suggests a bottleneck effect in eastern gorillas
Authors: Barks Sarah K. , Bauernfeind Amy L. , Bonar Christopher J. , Cranfield Michael R. , de Sousa Alexandra A. , Erwin Joseph M. , Hopkins William D. , Lewandowski Albert H. , Mudakikwa Antoine , Phillips Kimberley A. , Raghanti Mary Ann , Stimpson Cheryl D. , Hof Patrick R. , Zilles Karl , Sherwood Chet C. 
Published: August 2013

ABSTRACTWe describe an atypical neuroanatomical feature present in several primate species that involves a fusion between the temporal lobe (often including Heschl's gyrus in great apes) and the posterior dorsal insula, such that a portion of insular cortex forms an isolated pocket medial to the Sylvian fissure. We assessed the frequency of this fusion in 56 primate species (including apes, Old World monkeys, New World monkeys, and strepsirrhines) by using either magnetic resonance images or histological sections. A fusion between temporal cortex and posterior insula was present in 22 species (seven apes, two Old World monkeys, four New World monkeys, and nine strepsirrhines). The temporoinsular fusion was observed in most eastern gorilla (Gorilla beringei beringei and G. b. graueri) specimens (62% and 100% of cases, respectively) but was seen less frequently in other great apes and was never found in humans. We further explored the histology of this fusion in eastern gorillas by examining the cyto‐ and myeloarchitecture within this region and observed that the degree to which deep cortical layers and white matter are incorporated into the fusion varies among individuals within a species. We suggest that fusion between temporal and insular cortex is an example of a relatively rare neuroanatomical feature that has become more common in eastern gorillas, possibly as the result of a population bottleneck effect. Characterizing the phylogenetic distribution of this morphology highlights a derived feature of these great apes. J. Comp. Neurol. 522:844–860, 2014. © 2013 Wiley Periodicals, Inc.
Manipulating the Kinetics of Seeded Growth for Edge‐Selective Metal Deposition and the Formation of Concave Au Nanocrystals
Authors: Laskar Moitree , Zhong Xiaolan , Li Zhi‐Yuan , Skrabalak Sara E. 
Published: August 2013

AbstractBy manipulating the kinetics of seeded growth through judicious control of reaction conditions, edge‐selective metal deposition can be achieved to synthesize new Au nanostructures with face‐centered concavities, referred to herein as Au overgrown trisoctahedra. These nanostructures display higher sensitivity to changes in refractive index compared to both Au traditional trisoctahedra and the Au nanocube seeds from which they are grown. Often, concave nanostructures are achieved by selective etching processes or corner‐selective overgrowth and adopt a stellated profile rather than a profile with face‐centered concavities. The presented results illustrate another strategy toward concave nanostructures and can facilitate the synthesis of new concave nanostructures for applications in catalysis and chemical sensing.
An efficient cross layer based channel reservation method for vehicular networks
Authors: Saritha V. , Madhu Viswanatham V. 
Published: August 2013

SUMMARYThe swift growth of the mobile users and limited availability of bandwidth lead to the requirement of effective channel allocation process. Channel allocation becomes tedious in vehicular ad hoc network, as the mobility of the nodes is high. So, in this paper, we propose a method called as cross layer based channel reservation with preemption (CCRP) method that performs channel allocation process by estimating the handoffs in vehicular ad hoc networks. The time estimated is communicated from physical layer to medium access control layer using a cross‐layer design. The reusability concept is used, and the channels are divided into three groups. The different cells acquire different groups based on the database status and exclusively to avoid interference. Preemption is incorporated to give the highest priority to real time originating calls and real time handoff calls. The performance of the proposed method, CCRP, is compared with the legacy systems such as cooperative reservation of service channels and very fast handover scheme in terms of dropping probability, blocking probability, and handoff latency. The results show that the proposed algorithm, CCRP, performs better in comparison. Copyright © 2013 John Wiley & Sons, Ltd.
An improved anti‐collision protocol for radio frequency identification tag
Authors: Jia XiaoLin , Feng QuanYuan 
Published: August 2013

SummaryMany anti‐collision protocols have been proposed at present. Almost all known protocols exhibit an overall identification efficiency smaller than 50%. And all of them are proposed for general purpose applications and do not consider the distribution characteristic of tag IDs in different radio frequency identification (RFID) systems. In real world, there are many RFID systems, in which the tag IDs are mostly distributed continuously, such as in container terminals, warehouse management, supply chain management, and so on. This paper presents an efficient anti‐collision protocol, named improved collision tree protocol (ICT), to identify RFID tags simultaneously. The main novelties of this paper include that the duality and certainty principle is introduced and used in ICT to improve the tag identification efficiency, and the continuous and partially continuous distributions of tag IDs are taken into account in this paper. Both the theoretical and experimental results indicate that ICT improves the tag identification efficiency up to 100% when the tag IDs are distributed continuously, and always above 50% even when the tag IDs are distributed uniformly. For straightforward and efficient, ICT can be used in various RFID tag identification conditions, especially when the tag IDs are distributed continuously or partially continuously. Copyright © 2013 John Wiley & Sons, Ltd.
Partitioning of the total evapotranspiration in a Japanese cypress plantation during the growing season
Authors: Sun Xinchao , Onda Yuichi , Kato Hiroaki , Otsuki Kyoichi , Gomi Takashi 
Published: August 2013

ABSTRACTWe investigated the contribution of three evapotranspiration (ET) components including canopy interception (Ei), tree transpiration (Et) and forest floor evaporation (Ef) and identified the sources depth of evaporated water in a Japanese cypress stand. Monitoring primarily focused on the growing season of July–October 2011. In a 12 × 13 m plot with 28 trees with a DBH of 19.1 ± 3.9 cm, Ei was calculated as the difference between precipitation on an open field and precipitation under a canopy as the sum of throughfall and stemflow, and Et was measured using the Granier method. Ef was measured by weighing lysimeters. Total ET during the monitoring period was 446.3 mm, accounting for 47.5% of the total precipitation of 938.8 mm. Ei was the dominant evaporation flux and accounted for 53.6% of ET or 25.5% of rainfall, followed by Et with 33.7% of ET or 16.0% of rainfall. The average Et was 1.5 ± 0.6 mm d−1. It was well correlated with soil moisture at a depth of 5–15 cm, which reflected the forest properties, i.e. tree roots were exposed on the forest floor. Ef accounted for 12.7% of ET or 6.0% of rainfall with a daily mean of 0.55 ± 0.26 mm d−1, and was best correlated with soil moisture in the upper 5 cm of soil. These results can improve the understanding of water budget in forested watershed and also be used to build and validate hydrologic models for water resource managements. Copyright © 2013 John Wiley & Sons, Ltd.
Caudate nucleus‐dependent navigational strategies are associated with increased use of addictive drugs
Authors: Bohbot Veronique D. , Del Balso Daniel , Conrad Kate , Konishi Kyoko , Leyton Marco 
Published: August 2013

ABSTRACTThis study aimed to investigate the relationship between navigational strategies and the use of abused substances in a sample of healthy young adults. Navigational strategies were assessed with the 4‐on‐8 virtual maze (4/8VM), a task previously shown to dissociate between hippocampal‐dependent spatial navigational strategies and caudate nucleus‐dependent stimulus‐response navigational strategies. Spatial strategies involve learning the spatial relationships between the landmarks in an environment, while response learning strategies involve learning a rigid set of stimulus‐response type associations, e.g., see the tree, turn left. We have shown that spatial learners have increased gray matter and fMRI activity in the hippocampus compared with response learners, while response learners have increased gray matter and fMRI activity in the caudate nucleus. We were interested in the prevalence of use of substances of abuse in spatial and response learners because of the evidence that people who score high on traits such as novelty seeking, sensation seeking, reward seeking, and impulsivity, are more cue‐responsive and more likely to use substances of abuse. Since response learners show increased activity and gray matter in the caudate nucleus of the striatum, which is a brain area involved in addiction, we hypothesized that response learners would have a greater use of abused substances than spatial learners. Fifty‐five young adults were tested on the 4/8VM and completed a time‐line follow‐back assessment of drug and alcohol use. We found that response learners had smoked a significantly greater number of cigarettes in their lifetime than spatial learners, were more likely to have used cannabis, and had double the lifetime alcohol consumption. We discuss the possible relationship between substance abuse and response strategies as well as the implications for the hippocampus, risks of neurological and psychiatric disorders, and healthy cognition. © 2013 The Authors. Hippocampus Published by Wiley Periodicals, Inc.
New Pyrrole Alkaloids with Bulky N‐Alkyl Side Chains Containing Stereogenic Centers from Lycium chinense
Authors: Joung Youn Ui , Kil Yun‐Seo , Nam Joo‐Won , Jin Lee Yoo , Kim Jinwoong , Lee Dongho , Lee Je‐Hyun , Seo Eun‐Kyoung 
Published: August 2013

AbstractFour new pyrrole alkaloids, methyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1H‐pyrrol‐1‐yl]propanoate (1), methyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1H‐pyrrol‐1‐yl]‐3‐(4‐hydroxyphenyl)propanoate (2), dimethyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1H‐pyrrol‐1‐yl]butanedioate (3), and dimethyl 2‐[2‐formyl‐5‐(methoxymethyl)‐1H‐pyrrol‐1‐yl]pentanedioate (4), were isolated from the AcOEt extract of the fruits of Lycium chinense Miller (Solanaceae). The stereogenic center C(2) in the bulky N‐alkyl side chain in each of 1–4 seems to hold the H‐atoms of nearby CH2 groups, CH2(7′) and CH2(3) (if R≠H), leading to two different chemical shifts in the 1H‐NMR spectrum due to their diastereotopic characteristics. In the 1H‐NMR data of each of 2–4, the enhancement of HC(2) signal was inhibited by the R group, probably due to steric hindrance, and its chemical shift was influenced by the anisotropy effect. The structures of 1–4 were elucidated by analysis of various spectroscopic data, including 1D‐ and 2D‐NMR.
StarchSulfuric Acid (SSA) as Catalyst for a One‐Pot Synthesis of 1,5‐Diaryl‐1H‐pyrazoles
Authors: Hatamjafari Farhad 
Published: August 2013

AbstractProtocols with starchsulfuric acid (SSA) as reusable catalyst for the synthesis of aryl‐1H‐pyrazoles are described. SSA acted as an efficient and environmentally friendly catalyst for the regioselective condensation of BaylisHillman adducts 1 with phenylhydrazine hydrochloride leading to the new 1,5‐diaryl‐1H‐pyrazole 2a–2e in excellent yields (Scheme and Table 1).
Synthesis and Characterization of New Heptalenes with Extended π‐Systems Attached to Them
Authors: Maillefer‐El Houar Sarah , Uebelhart Peter , Linden Anthony , Hansen Hans‐Jürgen 
Published: August 2013

AbstractMethyl heptalenecarboxylates of type A and B with π(1) and π(2) substituents in 1,4‐relation (Scheme 1) were synthetized starting with dimethyl 1‐methylheptalene‐4,5‐dicarboxylates 5b and 6b derived from 7‐isopropyl‐1,4‐dimethylazulene (=guaiazulene) and 1,4,6,8‐tetramethylazulene by thermal reaction with dimethyl acetylenedicarboxylate. The further general way of proceeding for the introduction of the π(1) and π(2) substituents is displayed in Scheme 3, and the thus obtained methyl heptalene‐5‐carboxylates of type A and B are listed in Table 1. The CC bonds of the 2‐arylethenyl and 4‐arylbuta‐1,3‐dien‐1‐yl groups of π(1) and π(2) were in all cases (E)‐configured and showed s‐trans conformation at the CC bonds (X‐ray and 1H‐NOE evidence) in the B‐type as well as in the A‐type heptalenes (cf. Figs. 5–12).All B‐type heptalenes showed a strongly enhanced heptalene band I in the wavelength region 440–490 nm in hexane/CH2Cl2 9 : 1 (cf. Table 4 and Figs. 13–20). The A‐type heptalenes showed in this region only weak absorption, recognizable as shoulders or simply tailing of the dominating heptalene bands II/III (Table 5). Absorption band I of the B‐type heptalenes appeared almost at the same wavelength as the longest wavelength absorption band of comparable open‐chain α,ω‐diarylpolyenes (cf. Fig. 21). The cyclic double bond shift (DBS) of the A‐ and B‐type heptalenes could be photochemically steered in one or the other direction by selective irradiation (cf. Fig. 22).
Influence of food on pharmacokinetics of zolpidem from fast dissolving sublingual zolpidem tartrate tablets
Authors: Greenblatt David J. , Harmatz Jerold S. , Singh Nikhilesh N. , Roth Thomas , Harris Stephen C. , Kapil Ram P. 
Published: August 2013

AbstractIngesting food can impact the pharmacokinetics of sedative‐hypnotic drugs. A buffered zolpidem sublingual tablet (ZST) recently became available for the treatment of middle‐of‐the‐night awakening. In this randomized, open‐label, single‐site study, the pharmacokinetic profile of ZST was evaluated when administered while fasting and following a standard high‐fat meal (fed state). Healthy adults aged 18–64 years received a single morning dose of 3.5 mg ZST in the fed or fasting state. From 20 min to 3 h post‐dose, zolpidem plasma levels were lower in the fed state compared to the fasting state. After 4 h post‐dose (corresponding to “morning wake time”), higher zolpidem plasma levels were evident in the fed state. Area under the concentration‐time curve (AUC) values for the 0–8 h interval were 160 ng/mL h in the fed state and 203 ng/mL h in the fasting state (P < .001). In the fed versus fasting states, Cmax was 32.0 ng/mL versus 57.3 ng/mL (P < .001), respectively, and Tmax was 3.0 h versus 0.92 h (P < .001), respectively. Together these data suggest that administration of ZST in the fed state is not optimal for maximizing the likelihood of therapeutic benefit and minimizing the probability of residual sedation.