bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Performance Nonvolatile Transistor Memories Utilizing Functional Polyimide‐Based Supramolecular Electrets
Authors: Tung Wei‐Yao , Li Meng‐Hsien , Wu Hung‐Chin , Liu Hsin‐Yu , Hsieh Yun‐Ting , Chen Wen‐Chang 
Published: April 2016

AbstractWe report pentacene‐based organic field‐effect transistor memory devices utilizing supramolecular electrets, consisting of a polyimide, PI(6FOH‐ODPA), containing hydroxyl groups for hydrogen bonding with amine functionalized aromatic rings (AM) of 1‐aniline (AM1), 2‐naphthylamine (AM2), 2‐aminoanthracene (AM3), and 1‐aminopyrene (AM4). The effect of the phenyl ring size and composition of AM1–AM4 on the hole‐trapping capability of the fabricated devices was investigated systematically. Under an operating voltage under ±40 V, the prepared devices using the electrets of 100 % AM1–AM4/PI ratios exhibited a memory window of 0, 8.59, 25.97, and 29.95 V, respectively, suggesting that the hole‐trapping capability increased with enhancing phenyl ring size. The memory window was enhanced as the amount of AM in PI increased. Furthermore, the devices showed a long charge‐retention time of 104 s with an ON/OFF current ratio of around 103–104 and multiple switching stability over 100 cycles. This study demonstrated that the electrical characteristics of the OFET memory devices could be manipulated through the chemical compositions of the supramolecular electrets.
Boundary and Distributed Control for a Nonlinear Three‐Dimensional Euler‐Bernoulli Beam Based On Infinite Dimensional Disturbance Observer
Authors: Jiang Tingting , Liu Jinkun , He Wei 
Published: April 2016

AbstractControl problems in spatially distributed systems are challenging because the disturbance is of infinite dimensions. To this end, this paper discusses an infinite dimensional disturbance observer design, which is illustrated based on a partial differential equation (PDE) model of a nonlinear three‐dimensional Euler‐Bernoulli beam. The basic idea of the observer design is to modify the estimations based on the difference between the estimated output and actual output. Moreover, an auxiliary parameter system is established to help with the analysis. Then a Lyapunov function candidate consisting of the energy of the system, the observer error and an auxiliary term is given. After a series of analyses of the function, distributed controllers and boundary controllers based on the proposed observer are given to restrain vibration. Finally, by numerical simulations, the convergence of the observer is demonstrated, and the efficacy of control performance is also shown.
Oxidation of the N‐terminal domain of the wheat metallothionein Ec‐1 leads to the formation of three distinct disulfide bridges
Authors: Tarasava Katsiaryna , Chesnov Serge , Freisinger Eva 
Published: April 2016

ABSTRACTMetallothioneins (MTs) are low molecular weight proteins, characterized by a high cysteine content and the ability to coordinate large amounts of d10 metal ions, for example, Zn(II), Cd(II), and Cu(I), in form of metal‐thiolate clusters. Depending on intracellular conditions such as redox potential or metal ion concentrations, MTs can occur in various states ranging from the fully metal‐loaded holo‐ to the metal‐free apo‐form. The Cys thiolate groups in the apo‐form can be either reduced or be involved in disulfide bridges. Although oxidation‐mediated Zn(II) release might be a possible mechanism for the regulation of Zn(II) availability by MTs, no concise information regarding the associated pathways and the structure of oxidized apo‐MT forms is available. Using the well‐studied Zn2γ‐Ec‐1 domain of the wheat Zn6Ec‐1 MT we attempt here to answer several question regarding the structure and biophysical properties of oxidized MT forms, such as: (1) does disulfide bond formation increase the stability against proteolysis, (2) is the overall peptide backbone fold similar for the holo‐ and the oxidized apo‐MT form, and (3) are disulfide bridges specifically or randomly formed? Our investigations show that oxidation leads to three distinct disulfide bridges independently of the applied oxidation conditions and of the initial species used for oxidation, that is, the apo‐ or the holo‐form. In addition, the oxidized apo‐form is as stable against proteolysis as Zn2γ‐Ec‐1, rendering the currently assumed degradation of oxidized MTs unlikely and suggesting a role of the oxidation process for the extension of protein lifetime in absence of sufficient amounts of metal ions. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 295–308, 2016.
Conformational preferences and synthesis of isomers Z and E of oxazole‐dehydrophenylalanine
Authors: Staś Monika , Bujak Maciej , Broda Małgorzata A. , Siodłak Dawid 
Published: April 2016

ABSTRACTDehydrophenylalanine, ΔPhe, is the most commonly studied α,β‐dehydroamino acid. In nature, further modifications of the α,β‐dehydroamino acids were found, for example, replacement of the C‐terminal amide group by oxazole ring. The conformational properties of oxazole‐dehydrophenylalanine residue (ΔPhe‐Ozl), both isomers Z and E, were investigated. To determine all possible conformations, theoretical calculations were performed using Ac‐(Z/E)‐ΔPhe‐Ozl(4‐Me) model compounds at M06‐2X/6‐31++G(d,p) level of theory. Ac‐(Z/E)‐ΔPhe‐Ozl‐4‐COOEt compounds were synthesized and the conformational preferences of each isomer, Z and E, were investigated using FTIR and NMR‐NOE in solutions of increasing polarity (CHCl3, DMSO‐d6). The solid‐state low‐temperature structures of Ac‐(Z)‐ΔPhe‐Ozl‐4‐COOEt and its intermediate analog Ac‐(Z)‐ΔPhe‐Ozn(4‐OH)‐4‐COOEt were also determined. In a weakly polar environment, the ΔPhe‐Ozl residue has a tendency to adopt the conformation β2 with the calculated φ and ψ angles of −127° and 0° for the isomer Z and −170° and 26° for the isomer E. The increase of environment polarity favors the helical conformation α and the beta‐turn like conformation β, but the conformation β2 seems to be still accessible. The (E)‐ΔPhe‐Ozl residue can be obtained from the isomer Z in photoisomerization reaction. However, hydroxyl‐oxazoline‐dehydrophenylalanine ΔPhe‐Ozn(4‐OH) decomposes in such conditions. Alternatively, (E)‐ΔPhe‐NH2 can be applied as a substrate in the Hantzsch reaction. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 283–294, 2016.
Review: The ATPase mechanism of myosin and actomyosin
Authors: Geeves Michael A. 
Published: April 2016

ABSTRACTMyosins are a large family of molecular motors that use the common P‐loop, Switch 1 and Switch 2 nucleotide binding motifs to recognize ATP, to create a catalytic site than can efficiently hydrolyze ATP and to communicate the state of the nucleotide pocket to other allosteric binding sites on myosin. The energy of ATP hydrolysis is used to do work against an external load. In this short review I will outline current thinking on the mechanism of ATP hydrolysis and how the energy of ATP hydrolysis is coupled to a series of protein conformational changes that allow a myosin, with the cytoskeleton track actin, to operate as a molecular motor of distinct types; fast movers, processive motors or strain sensors. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 483–491, 2016.
Correlation between experience targets and competence for general surgery certification
Authors: De Siqueira J R , Gough M J 
Published: April 2016

Abstract

Background
Working time restrictions and public expectation have stimulated competence-based assessment in surgery. Nevertheless, certification of completion of training, and board accreditation across the developed world, still rely on experiential models based on indicative numbers as markers of operative competence. This study assessed the correlation between trainer assessment of competence and completion of indicative numbers.

Methods
Analysis of UK Intercollegiate Surgical Curriculum Programme portfolios of general surgical trainees in a single Local Education and Training Board allowed comparison of Procedure Based Assessment (PBA) scores (level of competence) for cholecystectomy, segmental colectomy and Hartmann's procedure with operative numbers.

Results
Among 121 trainees, there was a positive correlation between operative numbers and 1058 PBA scores for cholecystectomy (rs = 0·532, P &lt; 0·001), segmental colectomy (rs = 0·552, P &lt; 0·001) and Hartmann's procedure (rs= 0·663, P &lt; 0·001). Of those who completed the indicative numbers defined for each procedure to achieve certification of completion of training, only eight of 30 performing cholecystectomy, eight of 52 undertaking segmental colectomy and seven of 36 performing Hartmann's procedure had achieved three PBAs at the level considered to represent independent operating (level 4). More than half of all assessments (259 of 428, 60·5 per cent; 85 of 132 cholecystectomy, 140 of 217 colectomy and 34 of 79 Hartmann's) performed after trainees had completed their indicative numbers were scored below level 4.

Conclusion
A minimum number of index procedures did not reflect competence in a significant proportion of trainees. A more reliable tool is required for certification.
Multicentre observational study of outcomes after drainage of acute perianal abscess
Authors: Pearce L , Newton K , Smith S R , Barrow P , Smith J , Hancock L , Kirwan C C , Hill J ,   North West Research Collaborative
Published: April 2016

Abstract

Introduction
Management of perianal abscesses has remained largely unchanged for over 50 years. The evidence for postoperative wound packing is limited and may expose patients to painful procedures with no clinical benefit and at considerable increased cost.

Methods
Patients were recruited in 15 UK centres between December 2013 and October 2014. Outcome measures included number of dressing (pack) changes, healing, recurrence, return to work/normal function, postoperative fistula in ano and health utility scores (EQ-5D™). Pain was measured before, during and after dressing change on a visual analogue scale.

Results
Some 141 patients were recruited (median age 39 (range 18–86) years). The mean number of dressing changes in the first 3 weeks was 13 (range 0–21), equating to an annual cost to the National Health Service of €6 453 360 in England alone per annum. Some 43·8 per cent of wounds were healed by 8 weeks after surgery and 86 per cent of patients had returned to normal function. Some 7·6 per cent of abscesses had recurred and 26·7 per cent of patients developed a fistula in ano by 6 months following surgery. Patients reported a twofold to threefold increase in pain scores during and after dressing changes.

Conclusion
Recurrent abscess is rare and fistula occurs in one-quarter of the patients. Packing is painful and costly.
Simultaneous quantification of mycophenolic acid and its glucuronide metabolites in human plasma by an UPLC–MS/MS assay
Authors: Zhang Daping , Chow Diana S‐L. , Renbarger Jamie L. 
Published: April 2016

AbstractThe aim of this study was to develop a reliable UPLC–MS/MS assay for accurate quantification of mycophenolic acid (MPA) and its glucuronide conjugates in human plasma. Plasma proteins were precipitated with acetonitrile and the chromatographic separation was achieved on a C18 column with a gradient elution. The detection was performed by a triple quadrupole mass spectrometer in the positive electrospray ionization and multiple reaction monitoring mode. Linearity of the assay was demonstrated over the range of 20–10,000 ng/mL for MPA and MPA glucuronide (MPAG), and 2–1000 ng/mL for acyl MPA glucuronide in human plasma. The assay was precise and accurate with coefficient of variation and bias <15%. MPA and MPAG were stable at 25 °C up to 1 day in both heparin‐ and EDTA‐treated blood. In heparin‐ and EDTA‐plasma, MPA and MPAG were stable for at least 1 week at 25 and 4 °C, and 1 month at −20 °C. However, 99% acyl MPA glucuronide degraded in both heparin‐ and EDTA‐blood as well as plasma when stored at room temperature for 1 day. All the analytes remained stable for at least 3 months in acidified EDTA‐plasma at −80 °C. The assay was successfully applied on patients post hematopoietic stem cell transplantation. Copyright © 2016 John Wiley & Sons, Ltd.
Intraoperative frozen section analysis of the proximal bile ducts in hilar cholangiocarcinoma is of limited value
Authors: Mantel Hendrik T.J. , Westerkamp Andrie C. , Sieders Egbert , Peeters Paul M. J. G. , de Jong Koert P. , Boer Marieke T. , de Kleine Ruben H. , Gouw Annette S. H. , Porte Robert J. 
Published: April 2016

AbstractFrozen section analysis (FS) during cancer surgery is widely used to assess resection margins. However, in hilar cholangiocarcinoma (HCCA), FS may be less reliable because of the specific growth characteristics of the tumor. The aim of this study was to determine the accuracy and consequences of intraoperative FS of the proximal bile duct margins in HCCA. Between 1990 and 2014, 67 patients underwent combined extrahepatic bile duct resection and partial liver resection for HCCA with the use of FS. Sensitivity and specificity of FS was 68% and 97%, respectively. Seventeen of 67 patients (25%) displayed a positive bile duct margin at FS. The false‐negative rate was 16% (eight patients). Ten patients (15%) with a positive bile duct margin underwent an additional resection in an attempt to achieve negative margins, which succeeded in three patients (4%). However, only one of these three patients did not have concomitant lymph node metastases, which are associated with a poor prognosis by itself. The use of FS of the proximal bile duct is of limited clinical value because of the relatively low sensitivity, high risk of false‐negative results, and the low rate of secondary obtained tumor‐free resection margins. Supported by the literature, a new approach to the use of FS in HCCA should be adopted, reserving the technique only for cases in which a substantial additional resection is possible.
Medicinal Uses, Phytochemistry, and Pharmacology of Origanum onites (L.): A Review
Authors: Tepe Bektas , Cakir Ahmet , Sihoglu Tepe Arzuhan 
Published: April 2016

Origanum onites L., known as Turkish oregano, has great traditional, medicinal, preservative, and commercial importance. It is used for the treatment of several kinds of ailments, such as gastrointestinal disorders, diabetes, high cholesterol, leukemia, bronchitis, etc. In this review, traditional use, phytochemistry, and pharmacology of O. onites reported between 1988 and 2014 were discussed. This review was prepared based on literature survey on scientific journals and books from libraries and electronic sources, such as Web of Science, PubMed, Scopus, Google Scholar, etc. All databases were searched up to June 2014. Several different classes of terpenoids, triterpene acids, phenolic acids, hydroquinones, flavonoids, hydrocarbons, sterols, pigments, fatty acids, tocopherols, and inorganic compounds were detected mainly in the aerial parts of this plant. Pharmacological studies revealed that extracts obtained from several solvents and individual compounds exhibited antimicrobial, antiviral, antioxidant, insecticidal, anticancer, hepatoprotective, genotoxic, antidiabetic, cholinesterase inhibitory, anti‐inflammatory, analgesic activities, etc. O. onites, in general, exhibited remarkable activity potential in almost all test systems. The results of toxicity studies indicated that O. onites did not show any significant toxicity and mutagenicity on Drosophila and Salmonella. Toxicity of the extracts/essential oils and also individual compounds should be evaluated on mammalian cells to ensure their safety. The bioactivity of individual compounds aside from terpenoids should also be assessed in detail. Additionally, mode of action for the bioactive compounds should be evaluated to understand the complex pharmacological effects of these phytochemicals.
DNA Walker‐Regulated Cancer Cell Growth Inhibition
Authors: Li Feiran , Cha Tae‐Gon , Pan Jing , Ozcelikkale Altug , Han Bumsoo , Choi Jong Hyun 
Published: April 2016

AbstractWe demonstrate a DNAzyme‐based walker system as a controlled oligonucleotide drug AS1411 release platform for breast cancer treatment. In this system, AS1411 strands are released from fuel strands as a walker moves along its carbon nanotube track. The release rate and amount of anticancer oligonucleotides are controlled by the walker operation. With a walker system embedded within the collagen extracellular matrix, we show that this drug release system can be used for in situ cancer cell growth inhibition.
Diabetes insipidus uncovered during conservative management of complicated acute appendicitis
Authors: Mamtani Anita , Odom Stephen R. , Butler Kathryn L. 
Published: April 2016

Key Clinical MessageDiabetes insipidus (DI) arises from impaired function of antidiuretic hormone, characterized by hypovolemia, hypernatremia, polyuria, and polydipsia. This case is a reminder of the rare but challenging obstacle that undiagnosed DI poses in fasting surgical patients, requiring prompt recognition and vigilant management of marked homeostatic imbalances.
CF3: An Electron‐Withdrawing Substituent for Aromatic Anion Acceptors? “Side‐On” versus “On‐Top” Binding of Halides
Authors: Albrecht Markus , Yi Hai , Köksal Okan , Raabe Gerhard , Pan Fangfang , Valkonen Arto , Rissanen Kari 
Published: April 2016

AbstractThe ability of multiple CF3‐substituted arenes to act as acceptors for anions is investigated. The results of quantum‐chemical calculations show that a high degree of trifluoromethyl substitution at the aromatic ring results in a positive quadrupole moment. However, depending on the polarizability of the anion and on the substitution at the arene, three different modes of interaction, namely Meisenheimer complex, side‐on hydrogen bonding, or anion–π interaction, can occur. Experimentally, the side‐on as well as a η2‐type π‐complex are observed in the crystal, whereas in solution only side‐on binding is found.
Mechanistic Insight into the Intramolecular Benzylic C−H Nitrene Insertion Catalyzed by Bimetallic Paddlewheel Complexes: Influence of the Metal Centers
Authors: Zhang Xuepeng , Xu Huiying , Liu Xueping , Phillips David Lee , Zhao Cunyuan 
Published: April 2016

AbstractThe intramolecular benzylic C−H amination catalyzed by bimetallic paddlewheel complexes was investigated by using density functional theory calculations. The metal–metal bonding characters were investigated and the structures featuring either a small HOMO–LUMO gap or a compact SOMO energy scope were estimated to facilitate an easier one‐electron oxidation of the bimetallic center. The hydrogen‐abstraction step was found to occur through three manners, that is, hydride transfer, hydrogen migration, and proton transfer. The imido N species are more preferred in the Ru–Ru and Pd–Mn cases whereas coexisting N species, namely, singlet/triplet nitrene and imido, were observed in the Rh–Rh and Pd–Co cases. On the other hand, the triplet nitrene N species were found to be predominant in the Pd–Ni and Pd–Zn systems. A concerted asynchronous mechanism was found to be modestly favorable in the Rh–Rh‐catalyzed reactions whereas the Pd–Co‐catalyzed reactions demonstrated a slight preference for a stepwise pathway. Favored stepwise pathways were seen in each Ru–Ru‐ and Pd–Mn‐catalyzed reactions and in the triplet nitrene involved Pd–Ni and Pd–Zn reactions. The calculations suggest the feasibility of the Pd–Mn, Pd–Co, and Pd–Ni paddlewheel complexes as being economical alternatives for the expensive dirhodium/diruthenium complexes in C−H amination catalysis.
In Silico Olefin Metathesis with Ru‐Based Catalysts Containing N‐Heterocyclic Carbenes Bearing C60 Fullerenes
Authors: Martínez Juan Pablo , Vummaleti Sai Vikrama Chaitanya , Falivene Laura , Nolan Steven P. , Cavallo Luigi , Solà Miquel , Poater Albert 
Published: April 2016

AbstractDensity functional theory calculations have been used to explore the potential of Ru‐based complexes with 1,3‐bis(2,4,6‐trimethylphenyl)imidazolin‐2‐ylidene (SIMes) ligand backbone (A) being modified in silico by the insertion of a C60 molecule (B and C), as olefin metathesis catalysts. To this end, we investigated the olefin metathesis reaction catalyzed by complexes A, B, and C using ethylene as the substrate, focusing mainly on the thermodynamic stability of all possible reaction intermediates. Our results suggest that complex B bearing an electron‐withdrawing N‐heterocyclic carbene improves the performance of unannulated complex A. The efficiency of complex B is only surpassed by complex A when the backbone of the N‐heterocyclic carbene of complex A is substituted by two amino groups. The particular performance of complexes B and C has to be attributed to electronic factors, that is, the electronic‐donating capacity of modified SIMes ligand rather than steric effects, because the latter are predicted to be almost identical for complexes B and C when compared to those of A. Overall, this study indicates that such Ru‐based complexes B and C might have the potential to be effective olefin metathesis catalysts.
Synthesis of a pH‐Sensitive Hetero[4]Rotaxane Molecular Machine that Combines [c2]Daisy and [2]Rotaxane Arrangements
Authors: Waelès Philip , Riss‐Yaw Benjamin , Coutrot Frédéric 
Published: April 2016

AbstractThe synthesis of a novel pH‐sensitive hetero[4]rotaxane molecular machine through a self‐sorting strategy is reported. The original tetra‐interlocked molecular architecture combines a [c2]daisy chain scaffold linked to two [2]rotaxane units. Actuation of the system through pH variation is possible thanks to the specific interactions of the dibenzo‐24‐crown‐8 (DB24C8) macrocycles for ammonium, anilinium, and triazolium molecular stations. Selective deprotonation of the anilinium moieties triggers shuttling of the unsubstituted DB24C8 along the [2]rotaxane units.
Early–Late Heterometallic Complexes of Gold and Zirconium: Photoluminescence and Reactivity
Authors: Bestgen Sebastian , Schoo Christoph , Zovko Christina , Köppe Ralf , Kelly Rory P. , Lebedkin Sergei , Kappes Manfred M. , Roesky Peter W. 
Published: April 2016

AbstractOH functionalized triarylphosphines were used to assemble zirconocene‐based metalloligands with phosphine donor sites in varying positions. These complexes were subsequently treated with different gold precursors to obtain early–late heterometallic compounds in which the metal atoms exhibit different intermetallic distances. All compounds were fully investigated by spectroscopic techniques, photoluminescence measurements and single crystal X‐ray diffraction. Quantum chemical calculations were also performed. Some compounds show bright emission even at room temperature with quantum yields of up to 19 % (excitation at 350 nm). Furthermore, the reactivity of dimethyl zirconocene derivatives towards gold complexes was investigated, revealing simultaneous ligand exchange and transmetallation reactions.
Intercalation of Coordinatively Unsaturated FeIII Ion within Interpenetrated Metal–Organic Framework MOF‐5
Authors: Holmberg Rebecca J. , Burns Thomas , Greer Samuel M. , Kobera Libor , Stoian Sebastian A. , Korobkov Ilia , Hill Stephen , Bryce David L. , Woo Tom K. , Murugesu Muralee 
Published: April 2016

AbstractCoordinatively unsaturated FeIII metal sites were successfully incorporated into the iconic MOF‐5 framework. This new structure, FeIII‐iMOF‐5, is the first example of an interpenetrated MOF linked through intercalated metal ions. Structural characterization was performed with single‐crystal and powder XRD, followed by extensive analysis by spectroscopic methods and solid‐state NMR, which reveals the paramagnetic ion through its interaction with the framework. EPR and Mössbauer spectroscopy confirmed that the intercalated ions were indeed FeIII, whereas DFT calculations were employed to ascertain the unique pentacoordinate architecture around the FeIII ion. Interestingly, this is also the first crystallographic evidence of pentacoordinate ZnII within the MOF‐5 SBU. This new MOF structure displays the potential for metal‐site addition as a framework connector, thus creating further opportunity for the innovative development of new MOF materials.