bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two‐Photon‐Induced Fluorescence in New π‐Expanded Diketopyrrolopyrroles
Authors: Grzybowski Marek , Hugues Vincent , Blanchard‐Desce Mireille , Gryko Daniel T. 
Published: August 2014

AbstractStructurally unique π‐expanded diketopyrrolopyrroles (EDPP) were designed and synthesized. Strategic placement of a fluorene scaffold at the periphery of a diketopyrrolopyrrole through tandem Friedel–Crafts‐dehydration reactions resulted in dyes with supreme solubility. The structure of the dyes was confirmed by X‐ray crystallography verifying a nearly flattened arrangement of the ten fused rings. Despite the extended ring system, the dye still preserved good solubility and was further functionalized by using Pd‐catalyzed coupling reactions, such as the Buchwald–Hartwig amination. Photophysical studies of these new functional dyes revealed that they possess enhanced properties when compared with expanded DPPs in terms of two‐photon absorption cross‐section. It is further demonstrated that in addition to the initial diacetals, the final electrophilic cyclization step can also be applied to diketones. By placing two amine groups at peripheral positions of the resulting dyes, values of two‐photon absorption cross‐section on the level of 2000 GM around 1000 nm were achieved, which in combination with high fluorescence quantum yield (Φfl), generated a two‐photon brightness of approximately 1600 GM. These characteristics in combination with strong red emission (665 nm) make these new π‐expanded diketopyrrolopyrroles of major promise as two‐photon dyes for bioimaging applications. Finally, the corresponding N‐alkylated DPPs displayed a solid‐state fluorescence.
Computational Study of van der Waals Complexes between Borylenes and Hydrocarbons
Authors: Krasowska Małgorzata , Bettinger Holger F. 
Published: August 2014

AbstractThe addition of borylenes (RB) to prototypical carboncarbon multiple bonds (ethyne, ethene) and the insertion into a CH bond of methane involves weakly bound van der Waals complexes of the reaction partners according to computational chemistry methods. Geometries of all complexes were optimized using spin‐component scaled second‐order Møller–Plesset perturbation theory (SCS‐MP2) in combination with a quadruple‐ζ (def2‐QZVP) basis set. Energies were further refined using the coupled‐cluster (CCSD(T)) method in combination with basis sets up to quadruple‐ζ quality (def2‐QZVP and aug‐cc‐pVTZ). All of the complexes of borylenes studied correspond to shallow minima on their potential‐energy surfaces. Borylene complexes with ethyne are the most stable and those with methane are the least stable ones. Aminoborylene complexes BNHR with ethyne and ethene are stabilized mainly by NH⋅⋅⋅π interactions. Symmetry‐adapted perturbation theory (SAPT) was performed to analyze the nature of the interaction between borylene molecules and hydrocarbons. Most of the ethyne complexes are dominated by electrostatic interactions, whereas for most of the ethene and all of the methane complexes the interaction is mainly dispersive.
Trisphosphine‐Chelate‐Substituted Molybdenum and Tungsten Nitrosyl Hydrides as Highly Active Catalysts for Olefin Hydrogenations
Authors: Chakraborty Subrata , Blacque Olivier , Fox Thomas , Berke Heinz 
Published: August 2014

AbstractReaction of [M(NO)Cl3(NCMe)2] (M=Mo, W) with (iPr2PCH2CH2)2PPh (etpip) at room temperature afforded the syn/anti‐[M(NO)Cl3(mer‐etpip)] complexes (M=Mo, a; W, b; 3 a,b(syn,anti); syn and anti refer to the relative position of Ph(etpip) and NO). Reduction of 3 a,b(syn,anti) produced [M(NO)Cl2(mer‐etpip)] (4 a,b(syn)), [M(NO)Cl(NCMe)(mer‐etpip)] (5 a,b(syn,anti)), and [M(NO)Cl(η2‐ethylene)(mer‐etpip)] (6 a,b(syn,anti)) complexes. The hydrides [M(NO)H(η2‐ethylene)(mer‐etpip)] (7 a,b(syn,anti)) were obtained from 6 a,b(syn,anti) using NaHBEt3 (75 °C, THF) or LiBH4 (80 °C, Et3N), respectively. 7 a,b(syn,anti) were probed in olefin hydrogenations in the absence or presence of a hydrosilane/B(C6F5)3 mixture. The 7 a,b(syn,anti)/Et3SiH/B(C6F5)3 co‐catalytic systems were highly active in various olefin hydrogenations (60 bar H2, 140 °C), with maximum TOFs of 5250 h−1 (7 a(syn,anti)) and 8200 h−1 (7 b(syn,anti)) for 1‐hexene hydrogenation. The Et3SiH/(B(C6F5)3 co‐catalyst is anticipated to generate a [Et3Si]+ cation attaching to the ONO atom. This facilitates NO bending and accelerates catalysis by providing a vacant site. Inverse DKIE effects were observed for the 7 a(syn,anti)/Et3SiH/(B(C6F5)3 (kH/kD=0.55) and the 7 b(syn,anti)/Et3SiH/(B(C6F5)3 (kH/kD=0.65) co‐catalytic mixtures (20 bar H2/D2, 140 °C).
Unexpected Drastic Decrease in the Excited‐State Electronic Communication between Porphyrin Chromophores Covalently Linked by a Palladium(II) Bridge
Authors: Abdelhameed Mohammed , Karsenti Paul‐Ludovic , Langlois Adam , Lefebvre Jean‐François , Richeter Sébastien , Ruppert Romain , Harvey Pierre D. 
Published: August 2014

AbstractA dyad built up of a zinc(II) porphyrin and the corresponding free base, [Zn‐Fb], fused to N‐heterocyclic carbene (NHCs) ligands, respectively acting as singlet energy donor and acceptor, and a bridging trans‐PdI2 unit, along with the corresponding [Zn‐Zn] and [Fb‐Fb] dimers were prepared and investigated by absorption and emission spectroscopy and density functional computations. Despite favorable structural and spectroscopic parameters, unexpectedly slow singlet energy transfer rates are measured in comparison with the predicted values by the Förster theory and those observed for other structurally related dyads. This observation is rationalized by the lack of large molecular orbital (MO) overlaps between the frontier MOs of the donor and acceptor, thus preventing a double electron exchange through the trans‐PdI2 bridge, and by an electronic shielding induced by the presence of this same linker preventing the two chromophores to fully interact via their transition dipoles.
Acid/Base Switching of the Tautomerism and Conformation of a Dioxoporphyrin for Integrated Binary Subtraction
Authors: Ding Yubin , Li Xin , Hill Jonathan P. , Ariga Katsuhiko , Ågren Hans , Andréasson Joakim , Zhu Weihong , Tian He , Xie Yongshu 
Published: August 2014

AbstractCompared with most of the reported logic devices based on the supramolecular approach, systems based on individual molecules can avoid challenging construction requirements. Herein, a novel dioxoporphyrin DPH22 was synthesized and two of its tautomers were characterized by single‐crystal X‐ray diffraction studies. Compound DPH22 exhibits multichannel controllable stepwise tautomerization, protonation, and deprotonation processes through interactions with H+ and F− ions. By using the addition of H+ and F− ions as inputs and UV/Vis absorption values at λ=412, 510, 562, and 603 nm as outputs, the controlled tautomerism of DPH22 has been successfully used for the construction of an integrated molecular level half‐subtractor and comparator. In addition, this acid/base‐switched tautomerism is reversible, thus endowing the system with ease of reset and recycling; consequently, there is no need to modulate complicated intermolecular interactions and electron‐/charge‐transfer processes.
Synthesis of Pyridazinones through the Copper(I)‐Catalyzed Multicomponent Reaction of Aldehydes, Hydrazines, and Alkynylesters
Authors: Mantovani Anderson C. , Goulart Tales A. C. , Back Davi F. , Zeni Gilson 
Published: August 2014

AbstractThe copper‐catalyzed multicomponent cyclization reaction, which combined aldehydes, hydrazines, and alkynylesters, was applied in the synthesis of pyridazinones. The reaction was regioselective and gave only six‐membered pyridazinones in the complete absence of five‐membered pyrazoles or a regioisomeric mixture. During this investigation, the use of 2‐halobenzaldehyde as the starting material, under identical reaction conditions, gave 6‐(2‐ethoxyphenyl)pyridazinones after sequential Michael addition/1,2‐addition/Ullmann cross‐coupling reactions.
Ribonuclease A Inhibition by Carboxymethylsulfonyl‐Modified Xylo‐ and Arabinopyrimidines
Authors: Datta Dhrubajyoti , Dasgupta Swagata , Pathak Tanmaya 
Published: August 2014

AbstractA group of acidic nucleosides were synthesized to develop a new class of ribonuclease A (RNase A) inhibitors. Our recent study on carboxymethylsulfonyl‐modified nucleosides revealed some interesting results in RNase A inhibition. This positive outcome triggered an investigation of the role played by secondary sugar hydroxy groups in inhibiting RNase A activity. Uridines and cytidines modified with SO2CH2COOH groups at the 2′‐ and 3′‐positions show good inhibitory properties with low inhibition constant (Ki) values in the range of 109–17 μM. The present work resulted in a set of inhibitors that undergo more effective interactions with the RNase A active site, as visualized by docking studies.
Towards zero latency photonic switching in shared memory networks
Authors: Madarbux Muhammad Ridwan , Van Laer Anouk , Watts Philip M. , Jones Timothy M. 
Published: August 2014

SUMMARYOptical networks on chip based on silicon photonics have been proposed to reduce latency and power consumption in future chip multiprocessors. However, high performance chip multiprocessors use a shared memory model, which generates large numbers of short messages, creating high arbitration latency overhead for photonic switching networks. In this paper, we explore techniques that intelligently use information from the memory hierarchy to predict communication in order to setup photonic circuits with reduced or eliminated arbitration latency. Firstly, we present a switch scheduling algorithm, which arbitrates on a per memory transaction basis and holds open photonic circuits to exploit temporal locality. We show that this can reduce the average arbitration latency overhead by 60% and eliminate arbitration latency altogether for up to 70% of memory transactions. We then demonstrate that this switch scheduling algorithm operating with a central photonic crossbar or Clos switch has significant energy efficiency benefits over arbitration‐free photonic networks such as single writer multiple reader networks. Finally, we demonstrate that cache miss prediction can be used to predict 86% of more complex memory transactions involving multiple nodes or main memory. Copyright © 2014 John Wiley & Sons, Ltd.
Synthesis of Cyclophellitol, Cyclophellitol Aziridine, and Their Tagged Derivatives
Authors: Li Kah‐Yee , Jiang Jianbing , Witte Martin D. , Kallemeijn Wouter W. , van den Elst Hans , Wong Chung‐Sing , Chander Sharina D. , Hoogendoorn Sascha , Beenakker Thomas J. M. , Codée Jeroen D. C. , Aerts Johannes M. F. G. , van der Marel Gijs A. , Overkleeft Herman S. 
Published: August 2014

AbstractCyclitol epoxides and aziridines are potent and selective irreversible inhibitors of retaining glycosidases. We have previously reported on our studies on the use of activity‐based probes derived from cyclophellitol and from its aziridine analogue for activity‐based profiling of retaining β‐glucosidases in vitro, in situ, and in some examples also in vivo. In this work we disclose full details of the synthesis, purification, and analysis of a comprehensive panel of cyclophellitol analogues, all featuring the β‐glucose configuration and designed as tools for selective inhibition and/or imaging of human acid glucosylceramidase (epoxides) or as broad‐spectrum probes for retaining β‐glucosidases (aziridines).
Synthesis of α‐ and β‐Galactopyranose‐Configured Isomers of Cyclophellitol and Cyclophellitol Aziridine
Authors: Willems Lianne I. , Beenakker Thomas J. M. , Murray Benjamin , Gagestein Berend , van den Elst Hans , van Rijssel Erwin R. , Codée Jeroen D. C. , Kallemeijn Wouter W. , Aerts Johannes M. F. G. , van der Marel Gijsbert A. , Overkleeft Herman S. 
Published: August 2014

AbstractCyclophellitol and cyclophellitol aziridine are potent and irreversible mechanism‐based inhibitors of retaining β‐glucosidases. Alterations in the configuration of these compounds can lead to irreversible inhibition of different classes of retaining glycosidases. We have recently reported on the design of a set of α‐galactopyranose‐configured cyclophellitol and cyclophellitol aziridine derivatives that inhibit human retaining α‐galactosidases. Moreover, we have shown that fluorescently labeled derivatives enable the activity‐based profiling of these enzymes in vitro. In this report we describe in detail the synthetic strategies that were used to obtain these epoxide‐ and aziridine‐based probes. In addition, we describe the parallel synthesis of a set of β‐galactopyranose‐configured cyclophellitol isomers as putative inhibitors of retaining β‐galactosidases.
Construction of Efficient Solid Emitters with Tetraphenylethene Trimers for Non‐doped Blue OLEDs
Authors: Huang Jing , Sun Ning , Wang Jinyu , Tang Runli , Li Xuefeng , Dong Jingfeng , Li Qianqian , Ma Dongge , Li Zhen 
Published: August 2014

AbstractThree TPE trimers with meta or para linkage modes have been successfully synthesized. When fabricated as emissive layers in non‐doped OLEDs, they all exhibit blue or deep‐blue emissions with maximum current efficiency up to 4.03 cd A−1, further verifying the facile but ingenious approach by utilizing meta‐linkage mode in longer conjugated systems.
Precession electron diffraction‐assisted crystal phase mapping of metastable c‐GaN films grown on (001) GaAs
Authors: Ruiz‐Zepeda Francisco , Casallas‐Moreno Yenny L. , Cantu‐Valle Jesus , Alducin Diego , Santiago Ulises , José‐Yacaman Miguel , López‐López Máximo , Ponce Arturo 
Published: August 2014

ABSTRACTThe control growth of the cubic meta‐stable nitride phase is a challenge because of the crystalline nature of the nitrides to grow in the hexagonal phase, and accurately identifying the phases and crystal orientations in local areas of the nitride semiconductor films is important for device applications. In this study, we obtained phase and orientation maps of a metastable cubic GaN thin film using precession electron diffraction (PED) under scanning mode with a point‐to‐point 1 nm probe size beam. The phase maps revealed a cubic GaN thin film with hexagonal GaN inclusions of columnar shape. The orientation maps showed that the inclusions have nucleation sites at the cubic GaN {111} facets. Different growth orientations of the inclusions were observed due to the possibility of the hexagonal {0001} plane to grow on any different {111} cubic facet. However, the generation of the hexagonal GaN inclusions is not always due to a 60° rotation of a {111} plane. These findings show the advantage of using PED along with phase and orientation mapping, and the analysis can be extended to differently composed semiconductor thin films. Microsc. Res. Tech. 77:980–985, 2014. © 2014 Wiley Periodicals, Inc.
Orthorhombic YAlO3 – a novel many‐phonon SRS‐active crystal
Authors: Kaminskii Alexander A. , Lux Oliver , Hanuza Jerzy , Rhee Hanjo , Eichler Hans Joachim , Yoneda Hitoki , Zhang Jian , Tang Dingyuan , Shirakawa Akira 
Published: August 2014

AbstractIn single crystals of orthorhombic YAlO3, widely known as a host‐matrix for Ln3+‐lasant ions, many‐phonon stimulated Raman scattering interactions as well as different manifestations of cascaded and cross‐cascaded nonlinear χ(3)↔χ(3) processes are initiated by picosecond laser pulses. The scientific and applicative potential of YAlO3 crystals is considerably expanded by the demonstration of its SRS properties. In particular, the studies revealed the manifestation of eight χ(3)‐active vibrational modes. The corresponding Stokes and anti‐Stokes lines have been assigned and the steady‐state Raman gain coefficients related to the strongest phonon mode have been estimated. In addition, a short review presents the stimulated emission channels of its Ln3+‐ions together with some χ(3)‐nonlinear laser properties of crystals belonging to the binary Y2O3‐Al2O3 system.
Fair treatment comparisons in observational research
Authors: Lopiano Kenneth K. , Obenchain Robert L. , Young S. Stanley 
Published: August 2014

AbstractThe proliferation of electronic health records, driven by advances in technology and legislative measures, is stimulating interest in the analysis of passively collected administrative and clinical data. Observational data present exciting challenges and opportunities to researchers interested in comparing the effectiveness of different treatment regimes and, as personalized medicine requires, estimating how effectiveness varies among subgroups. In this study, we provide new motivation for the local control approach to the analysis of large observational datasets in which patients are first clustered in pretreatment covariate space and treatment comparisons are made within subgroups of similar patients. The motivation for such an analysis is that the resulting local treatment effect estimates make inherently fair comparisons even when treatment cohorts suffer variation in balance (treatment choice fraction) across pretreatment covariate space. We use an example of Simpson's paradox to show that estimates of the overall average treatment effect, which marginalize over covariate space, can be misleading. Thus, we provide an alternative definition that uses a single, shared marginal distribution to define overall treatment comparisons that are inherently fair given the observed covariates. However, we also argue that overall treatment comparisons should no longer be the focus of comparative effectiveness research; the possibility that treatment effectiveness does vary across patient subpopulations must not be left unexplored. In the spirit of the now ubiquitous concept of personalized medicine, estimating heterogeneous treatment effects in clinically relevant subgroups will allow for, within the limits of the available data, fair treatment comparisons that are more relevant to individual patients.
The Effect of Doppler Ultrasound on Early Vascular Interventions and Clinical Outcomes After Liver Transplantation
Authors: Lee Hannah , Lim Chae‐Won , Yoo Seok Ha , Koo Chang‐Hoon , Kwon Woo‐Il , Suh Kyung‐Suk , Ryu Ho Geol 
Published: August 2014

AbstractBackground
During the immediate postoperative period after liver transplantation (LT), postoperative bleeding and vascular complications (stenosis, thrombosis) are the two most common complications that require therapeutic decisions. Doppler ultrasound (DUS) is the established method for screening vascular patency after LT during the immediate postoperative period. The objective of our study was to evaluate the impact of DUS performed on postoperative days (POD) 1 and 2 on early vascular interventions.Methods
We studied 200 patients who had undergone living donor or deceased donor liver transplantation between January 2011 and March 2012. Postoperative liver DUS findings of up to POD 14, including patency of hepatic artery, portal vein, and hepatic vein, were retrieved. Patients with normal DUS findings on POD 1 and POD 2 were classified as the normal early DUS group. Patients with abnormal DUS findings at POD1 or POD2 were classified as the abnormal early DUS group. Frequency of vascular interventions was compared between the two groups. Risk factors that predict vascular interventions also were assessed.Results
On POD 1 and 2, 81.5 % (163/200) had normal DUS findings and management was not altered by subsequent DUS findings. Two patients in the normal group were found to have hepatic artery dissection and hepatic vein thrombosis on routine CT on POD 7 and received vascular intervention. DUS results in the two patients were normal until POD 6, but DUS performed after the CT on POD 7 were consistent with the CT findings. Of the 37 recipients who showed abnormal DUS findings on POD 1 or 2, the DUS findings were normalized or unchanged thereafter in 33 patients and no vascular interventions were performed. Two patients underwent hepatic artery thrombectomy on POD 2, one patient required a portal vein thrombectomy on POD 1, and one patient died on POD 3 due to bleeding. The overall incidence of vascular complication requiring vascular interventions was 2.5 %. Logistic regression identified abnormal DUS findings on POD 1 or 2 as an independent risk factor of vascular complications requiring intervention.ConclusionsIn LT recipients who demonstrate normal DUS findings in the first 2 postoperative days, additional DUS screening may have value only when clinically indicated.
A Pilot Study of BRCA Mutation Carriers’ Knowledge About the Clinical Impact of Prophylactic‐oophorectomy and Views on Fertility Consultation: A Single‐Center Pilot Study
Authors: Kim J. , Skrzynia C. , Mersereau J. E. 
Published: August 2014

AbstractBRCA mutation carriers will experience early surgically induced menopause following prophylactic bilateral salpingo‐oophorectomy (PBSO). This pilot study aimed to investigate their (1) knowledge about the clinical impact of PBSO; (2) views on fertility consultation (FC)/fertility preservation (FP) treatment; and (3) difficulties in conceiving compared to non‐carriers. A cross‐sectional, single institution web‐survey was performed at a university‐based IVF center. Women aged 18–50 years who were screened for BRCA gene mutations from 2005 to 2013 were recruited via mail. Forty‐one BRCA‐positive and 110 BRCA‐negative women completed the survey (response rate: 50 %). The knowledge about the reproductive impact of PBSO was limited, with the majority of women in this highly educated sample only identifying the correct response 64 % of the time. Among BRCA mutation carriers, 24 (59 %) had positive views about FC/FP treatments. A larger proportion of women with no children at the time of BRCA testing, and those who were non‐white tended to have positive views toward FP. Women with, versus without, BRCA mutations were more likely to have difficulty in conceiving (p = 0.08). This well‐educated group had limited knowledge about the reproductive clinical impact of PBSO, or the benefit of a FP before PBSO. Most women with BRCA mutations were interested in FC/FP treatment if they had not completed childbearing at the time of screening. Targeted referrals for FC at the time of BRCA screening may help women improve knowledge and allow improved decision‐making about reproductive options.
Amide‐Based Surfactants from Methyl Glucoside as Potential Emulsifiers
Authors: Salman Salih Mahdi , Heidelberg Thorsten , Hussen Rusnah Syahila Duali , Tajuddin Hairul Anuar Bin 
Published: August 2014

AbstractA series of amide‐linked surfactants from methyl glucoside was synthesized and investigated for their potential use as water‐in‐oil emulsifiers. The synthetic concept combined a nucleophilic substitution approach with a Staudinger coupling of the intermediate azide. Both straight and Guerbet‐type branched fatty acids ranging from C8 to C16 were applied. All surfactants exhibited very high Krafft temperatures, which were related to the amide linkage and exclusively formed the hexagonal H1‐phase. The Guerbet C16 surfactant enabled the formation of a stable water‐in‐oil gel at ambient temperature, which, however, required heating to form the corresponding fluid emulsion.