bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antioxidant defense and oxidative damage vary widely among high‐altitude residents
Authors: Janocha Allison J. , Comhair Suzy A. A. , Basnyat Buddha , Neupane Maniraj , Gebremedhin Amha , Khan Anam , Ricci Kristin S. , Zhang Renliang , Erzurum Serpil C. , Beall Cynthia M. 
Published: July 2017

AbstractObjectivesPeople living at high altitude experience unavoidable low oxygen levels (hypoxia). While acute hypoxia causes an increase in oxidative stress and damage despite higher antioxidant activity, the consequences of chronic hypoxia are poorly understood. The aim of the present study is to assess antioxidant activity and oxidative damage in high‐altitude natives and upward migrants.MethodsIndividuals from two indigenous high‐altitude populations (Amhara, n = 39), (Sherpa, n = 34), one multigenerational high‐altitude population (Oromo, n = 42), one upward migrant population (Nepali, n = 12), and two low‐altitude reference populations (Amhara, n = 29; Oromo, n = 18) provided plasma for measurement of superoxide dismutase (SOD) activity as a marker of antioxidant capacity, and urine for measurement of 8‐hydroxy‐2′‐deoxyguanosine (8‐OHdG) as a marker of DNA oxidative damage.ResultsHigh‐altitude Amhara and Sherpa had the highest SOD activity, while highland Oromo and Nepalis had the lowest among high‐altitude populations. High‐altitude Amhara had the lowest DNA damage, Sherpa intermediate levels, and high‐altitude Oromo had the highest.ConclusionsHigh‐altitude residence alone does not associate with high antioxidant defenses; residence length appears to be influential. The single‐generation upward migrant sample had the lowest defense and nearly the highest DNA damage. The two high‐altitude resident samples with millennia of residence had higher defenses than the two with multiple or single generations of residence.
Unified Total Synthesis of Polyoxins J, L, and Fluorinated Analogues on the Basis of Decarbonylative Radical Coupling Reactions
Authors: Fujino Haruka , Nagatomo Masanori , Paudel Atmika , Panthee Suresh , Hamamoto Hiroshi , Sekimizu Kazuhisa , Inoue Masayuki 
Published: July 2017

AbstractPolyoxins J (1 a) and L (1 b) are important nucleoside antibiotics. The complex and densely functionalized dipeptide structures of 1 a and 1 b contain thymine and uracil nucleobases, respectively. Herein we report the unified total synthesis of 1 a, 1 b, and their artificial analogues 1 c and 1 d with trifluorothymine and fluorouracil structures. Decarbonylative radical coupling between α‐alkoxyacyl tellurides and a chiral glyoxylic oxime ether led to chemo‐ and stereoselective construction of the ribonucleoside α‐amino acid structures of 1 a–d without damaging the preinstalled nucleobases. The high applicability of the radical‐based methodology was further demonstrated by preparation of the trihydroxynorvaline moiety of 1 a–d. The two amino acid fragments were connected and elaborated into 1 a–d (longest linear sequence: 11 steps). Compounds 1 a and 1 b assembled in this way exhibited potent activity against true fungi, while only 1 d was active against Gram‐positive bacteria.
Enantioselective Construction of Trifluoromethoxylated Stereogenic Centers by a Nickel‐Catalyzed Asymmetric Suzuki–Miyaura Coupling of Secondary Benzyl Bromides
Authors: Huang Weichen , Wan Xiaolong , Shen Qilong 
Published: July 2017

AbstractTrifluoromethoxy‐substituted stereogenic centers can be constructed with high enantioselectivity by a nickel‐catalyzed Suzuki–Miyaura coupling of readily available α‐bromobenzyl trifluoromethyl ethers with a variety of aryl pinacol boronates. The coupling proceeds under mild reaction conditions, and a variety of common functional groups, such as fluoride, chloride, bromide, ester, enolizable ketone, nitro, cyano, amino, and vinyl moieties, were well tolerated. Furthermore, the reaction can be easily scaled up to gram quantities without a decrease in enantioselectivity.
Enzymatic and Chemoenzymatic Three‐Step Cascades for the Synthesis of Stereochemically Complementary Trisubstituted Tetrahydroisoquinolines
Authors: Erdmann Vanessa , Lichman Benjamin R. , Zhao Jianxiong , Simon Robert C. , Kroutil Wolfgang , Ward John M. , Hailes Helen C. , Rother Dörte 
Published: July 2017

AbstractChemoenzymatic and enzymatic cascade reactions enable the synthesis of complex stereocomplementary 1,3,4‐trisubstituted tetrahydroisoquinolines (THIQs) with three chiral centers in a step‐efficient and selective manner without intermediate purification. The cascade employs inexpensive substrates (3‐hydroxybenzaldehyde and pyruvate), and involves a carboligation step, a subsequent transamination, and finally a Pictet–Spengler reaction with a carbonyl cosubstrate. Appropriate selection of the carboligase and transaminase enzymes enabled the biocatalytic formation of (1R,2S)‐metaraminol. Subsequent cyclization catalyzed either enzymatically by a norcoclaurine synthase or chemically by phosphate resulted in opposite stereoselectivities in the products at the C1 position, thus providing access to both orientations of the THIQ C1 substituent. This highlights the importance of selecting from both chemo‐ and biocatalysts for optimal results.
Graphene and poly(ionic liquid) modified polyurethane sponges with enhanced flame‐retardant properties
Authors: Wei Huijuan , Zhu Zhaoqi , Sun Hanxue , Mu Peng , Liang Weidong , Li An 
Published: July 2017

ABSTRACTGraphene (Gr) and poly(ionic liquid) (PIL) modified polyurethane (PU) sponges with enhanced flame‐retardant properties were prepared by the direct dip coating of Gr and ionic liquid (IL) monomers onto a PU sponge followed by the polymerization of IL monomers under thermal initiation. With a content of 1.5% Gr in IL, the limiting oxygen index (LOI) of PU–PIL–Gr was 26.1%, whereas the neat PU sponge showed an LOI of only 17.9%. The horizontal flame test results indicate that PIL–Gr prevented horizontal flame spread and eliminated melt dripping. Compared with that of the neat PU sponge, the peak heat release rate of PU–PIL–Gr decreased about 22.0%. These improvements on flame retardancy might have been due to a hybrid flame retardant originating from Gr (which acted as carbon source) and PIL (which contained the flame‐retardant elements) in the PU sponge and the formation of protective layers, which isolated the oxygen and heat more effectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45477.
Vergleichende Untersuchungen zum räumlichen Erdwiderstand mit der Kinematischen‐Elemente‐Methode
Authors: Schmüdderich Christoph , Gußmann Peter , König Diethard , Schanz Tom 
Published: July 2017

AbstractDie Bestimmung des Erdwiderstands gehört zu den grundlegenden Aufgaben in der Geotechnik und ist allgemein als ein Traglastproblem zu behandeln. Mithilfe der Kinematischen‐Elemente‐Methode (KEM), welche eine geeignete Methode darstellt, um Tragfähigkeiten und Standsicherheiten im Grenzzustand zu berechnen, wird im vorliegenden Beitrag das Problem des räumlichen Erdwiderstands untersucht und eine umfangreiche Parameterstudie durchgeführt. Aus den Ergebnissen werden für variable Reibungswinkel, Wandreibungswinkel sowie Seitenverhältnisse die räumlichen Erdwiderstandsbeiwerte für den Anteil aus Bodeneigengewicht abgeleitet und in Form von Tabellen und Diagrammen präsentiert. Es zeigt sich, dass auch im räumlichen Fall durch Verfeinerung existierender KEM‐Mechanismen Bruchzustände genauer abgebildet und geringere Erdwiderstandsbeiwerte bestimmt werden können. Der Vergleich mit kinematischen Ansätzen aus der Literatur sowie der deutschen Norm ergibt, dass mit der KEM gute Abschätzungen des räumlichen Erdwiderstands möglich sind.
A Computational Study of the Intermolecular [2+2+2] Cycloaddition of Acetylene and C60 Catalyzed by Wilkinson's Catalyst
Authors: Artigas Albert , Lledó Agustí , Pla‐Quintana Anna , Roglans Anna , Solà Miquel 
Published: July 2017

AbstractThe functionalization of fullerenes helps to modulate their electronic and physicochemical properties, generating fullerene derivatives with promising features for practical applications. Herein, DFT is used to explore the attachment of a cyclohexadiene ring to C60 through a rhodium‐catalyzed intermolecular [2+2+2] cycloaddition of C60 and acetylene. All potential reaction paths are analyzed and it can be concluded that the [2+2+2] cycloaddition of C60 and two acetylene molecules catalyzed by [RhCl(PPh3)3], yielding a cyclohexadiene ring fused to a [6,6] bond of C60, is energetically feasible.
Total Synthesis of the Marine Natural Product Hemiasterlin by Organocatalyzed α‐Hydrazination
Authors: Lang Jan Hendrik , Jones Peter G. , Lindel Thomas 
Published: July 2017

AbstractAn efficient synthesis of the potently cytotoxic marine peptide hemiasterlin is presented. The tetramethyltryptophan moiety is assembled by tert‐prenylation of indole, followed by the high‐yielding organocatalyzed α‐hydrazination of a sterically congested aldehyde with excellent enantioselectivity. 2‐Bromo‐N‐ethylpyridinium tetrafluoroborate (BEP)‐mediated peptide coupling completes the synthesis, being the first approach that does not employ chiral auxiliaries. A novel phenonium‐type rearrangement of the indole system occurred when subjecting dihydroxylated 3‐tert‐prenylindole to Mitsunobu conditions.
Tuning the Effects of Bacterial Membrane Permeability through Photo‐Isomerization of Antimicrobial Cationic Amphiphiles
Authors: Salta Joana , Benhamou Raphael I. , Herzog Ido M. , Fridman Micha 
Published: July 2017

AbstractSeveral important antimicrobial drugs act by permeabilizing cell membranes. In this study, we showed that the intensity of membrane permeability caused by antimicrobial cationic amphiphiles can be modified not only by their concentration but also through light‐induced isomerization of their lipid segment. Two types of photo‐isomerizable cationic amphiphiles were developed and the effects of photo‐isomerization on bacterial growth and membrane permeability were evaluated. One photo‐isomer inhibited cell growth and division, whereas the other photo‐isomer led to a rapid and lethal bacterial membrane‐disrupting effect. The switch from “on” to “off” can be obtained by either the cis‐ or trans‐isomer depending on the bacterial strain and the type of cationic amphiphile. These cationic amphiphiles offer a novel tool for research and industrial applications that require light‐controlled bacterial membrane permeabilization.
High‐Quality GaSb and GaInSb Crystals Prepared by Vertical Bridgman Method
Authors: Wang Jinwei , Wang Liguo , Teng Dongxiao , Zhai Shenqiu , Liu Juncheng 
Published: July 2017

AbstractHigh‐quality GaSb and Ga1‐xInxSb (x = 0.14) crystals were grown via the vertical Bridgman (VB) method. The lattice structure, morphology, optical, and transport properties of the GaSb and GaInSb crystals were characterized. The influence of the indium doping on the physical properties of the GaSb crystal was also investigated. The results demonstrate that the indium doping maintains the zinc‐blende lattice structure of the GaSb crystal. The segregation of indium is very low, with the radial and axial concentration variation of 2.32% and 4.84%, respectively. The indium doping significantly reduces the dislocation density down to 1.275 × 103 cm−2. The band gap of the indium‐doped GaSb is reduced to 0.549 eV, consistent with the decreased infrared transmission measured by FTIR. Surprisingly, the indium doping changes the majority carrier type of the crystal, from p‐type in the pristine GaSb crystal to n‐type in the GaInSb crystal. Compared to the GaSb crystal, the GaInSb crystal shows enhanced transport properties, with carrier mobility increased to 2.512 × 103 cm2/(V•s) and resistivity reduced to 0.521 × 10−3 ohm•cm.
To forage, mate, or thermoregulate: Influence of resource manipulation on male rattlesnake behavior
Authors: Tetzlaff Sasha J. , Carter Evin T. , DeGregorio Brett A. , Ravesi Michael J. , Kingsbury Bruce A. 
Published: July 2017

AbstractMale animals should preferentially allocate their time to performing activities that promote enhancing reproductive opportunity, but the need to acquire resources for growth and survival may compete with those behaviors in the short term. Thus, behaviors which require differing movement patterns such as ambushing prey and actively searching for mates can be mutually exclusive. Consequently, males that succeed at foraging could invest greater time and energy into mate searching. We radio‐tracked sixteen male massasauga rattlesnakes (Sistrurus catenatus) and supplemented the diets of half the snakes with mice across an active season. We tested the predictions that reduced foraging needs would allow fed snakes to move (i.e., mate search) more, but that they would consequently be stationary to thermoregulate less, than unfed controls. Contrary to our first prediction, we found no evidence that fed snakes altered their mate searching behavior compared to controls. However, we found controls maintained higher body temperatures than fed snakes during the breeding season, perhaps because fed snakes spent less time in exposed ambush sites. Fed snakes had higher body condition scores than controls when the breeding season ended. Our results suggest the potential costs incurred by devoting time to stationary foraging may be outweighed by the drive to increase mating opportunities. Such instances may be especially valuable for massasaugas and other temperate reptiles that can remain inactive for upwards of half their lives or longer in some cases, and for female rattlesnakes that generally exhibit biennial or more protracted reproductive cycles.
Equimolar mixture of nitroux oxyde and oxygen during post‐operative physiotherapy in patients with cerebral palsy: A randomized, double‐blind, placebo‐controlled study
Authors: Delafontaine A. , Presedo A. , Mohamed D. , Lopes D. , Wood C. , Alberti C. 
Published: July 2017

AbstractBackgroundThe administration of an equimolar mixture of nitrous oxide and oxygen (N2O) is recommended during painful procedures. However, the evaluation of its use during physiotherapy after surgery has not been reported, although pain may hamper physiotherapy efficiency. This study investigated whether the use of N2O improves the efficacy of post‐operative physiotherapy after multilevel surgery in patients with cerebral palsy.MethodIt was a randomized 1:1, double‐blind, placebo‐controlled study. All patients had post‐operative physiotherapy starting the day after surgery. Patients received either N2O or placebo gas during the rehabilitation sessions. All patients had post‐operative pain management protocol, including pain medication as needed for acute pain. The primary objective was to reach angles of knee flexion of 110° combined with hip extension of 10°, with the patient lying prone, within six or less physiotherapy sessions. Secondary evaluation criteria were the number of sessions required to reach the targeted angles, the session‐related pain intensity and the analgesics consumption for managing post‐operative pain.ResultsSixty‐four patients were enrolled. Targeted angles were achieved more often in the N2O group (23 of 32, 72%, vs. Placebo: 13/ of 32, 41%; p = 0.01).ConclusionThe administration of N2O during post‐operative physiotherapy can help to achieve more quickly an improved range of motion, and, although not significant in our study, to alleviate the need for pain medication. Further studies evaluating the administration of N2O in various settings are warranted.SignificanceDuring this randomized placebo‐controlled double‐blind study, children receiving nitrous oxide and oxygen (N2O) achieved more often the targeted range of motion during physiotherapy sessions after multilevel surgery. Compared to placebo, nitrous oxide and oxygen (N2O) enabled a better management of acute pain related to physiotherapy procedures.
Chronoamperometric Biosensor for Protease Activity Assay and Inhibitor Screening
Authors: El Harrad Loubna , Amine Aziz 
Published: July 2017

AbstractHerein, we report an electrochemical biosensor for the measurement of proteins and protease activity using carbon nanopowder paste electrode modified with tyrosinase. The measurement of proteins is based on the amperometric measurement of the enzymatic product, tyrosine, at low applied potential (i.e +0.05 V vs. Ag/AgCl), in a linear range from 1 μg/mL to 10 μg/mL for casein and albumin bovine serum. This biosensor is also used to assess the enzymatic activity of the enzymes namely trypsin and proteinase K, observing a detection limit of 0.02 mU/mL (S/N=3). The ability of this assay to monitor the trypsin activity is exploited to investigate its inhibition by leupeptin. The trypsin kinetic interactions reveal uncompetitive binding of leupeptin with 50 % inhibition equal to 3.75 μM, a dynamic range of 0.25–10 μM, and a detection limit of 0.25 μM. The assay developed can be considered as general activity assay of any protease with the advantages of good storage stability (few weeks), low detection limit and ability to analyse turbid and colored samples.
Finite element analysis of damage and failure of reinforced concrete members under earthquake loading
Authors: Moharrami Mohammadreza , Koutromanos Ioannis 
Published: July 2017

SummaryThis paper presents a three‐dimensional analysis framework, based on the explicit finite element method, for the simulation of reinforced concrete components under cyclic static and dynamic loading. A recently developed triaxial constitutive model for concrete is combined with a material model for reinforcing steel which can account for rupture due to low‐cycle fatigue. The reinforcing bars are represented with geometrically nonlinear beam elements to account for buckling of the reinforcement. The strain penetration effect is also accounted for in the models. The modeling scheme is used in a commercial finite element program and validated with the results of experimental static and dynamic tests on reinforced concrete columns and walls. The analyses are supplemented with a parametric study to investigate the impact of several modeling assumptions on the obtained results.
The role of eddies in solute transport and recovery in rock fractures: Implication for groundwater remediation
Authors: Lee Seung Hyun , Yeo In Wook , Lee Kang‐Kun , Lee Won Sang 
Published: July 2017

AbstractA better understanding of solute transport and retention mechanism in rock fractures has been challenging due to difficulty in their direct observations in microscale rough‐walled fractures. Six representative troughs in a rough‐walled fracture were selected for microscale observations of eddy formation with increasing flow velocity and its effect on spatiotemporal changes of solute concentration. This experimental study was enabled by a microscale visualization technique of micro particle image velocimetry. With increasing flow velocity (Re ≤ 2.86), no eddies were generated, and solutes along the main streamlines transported rapidly, whereas those near the wall moved slowly. A larger amount of solutes remained trapped at all troughs at Re = 2.86 than Re < 1. For Re = 8.57, weak eddies started to be developed at the troughs on the lee side, which little contributed to overall solute flushing in the fracture. Accordingly, a large of amount of water was needed for solute flushing. The flow condition of 1 < Re < 10, before a full development of eddies, was least favourable in terms of time and amount of remediation fluid required to reach a target concentration. After large eddies were fully developed at troughs on the lee side for Re = 17.13, solutes were substantially reduced by eddies with less amount of water. Fully developed eddies were found to enhance solute transport and recovery, as opposed to a general consensus that eddies trap and delay solutes. Direct inflow into troughs on the stoss side also made a great contribution to solute flushing out of the troughs. This study indicates that fully developed eddies or strong inflows at troughs are highly possible to form for Re > 10 and this flow range could be favourable for efficient remediation.
Degree of conversion and cross‐link density within a resin‐matrix composite
Authors: Al‐Zain Afnan O. , Eckert George J. , Lukic Henry , Megremis Spiro J. , Platt Jeffrey A. 
Published: July 2017

AbstractThe aims of this study were to profile light radiated from two light‐curing units (LCUs) and evaluate profile relationship to polymerization patterns within a resin‐matrix composite (RMC). Beam profiles of one multiple emission peak light‐emitting‐diode and one quartz‐tungsten‐halogen curing‐unit were measured using a beam profiler/spectrometer system. A camera‐based profiler and an integrating sphere/spectrometer assembly were used to evaluate each LCU beam. Polymerization patterns within a nano‐hybrid RMC were investigated using a mapping approach by assessing the degree of conversion utilizing micro‐Raman spectroscopy and indirectly estimating cross‐link‐density by repeated microhardness testing before and after exposure to ethanol (%KH reduction, n = 3). The irradiance received on the top and bottom specimen surfaces from both LCUs was measured using a MARC‐RC system. The investigated beam profile area from both LCUs was non‐uniform and yielded localized discrepancies in DC (55.7–74.9%) and %KH reduction (26.7–54.1%). The LCU irradiance received at the bottom of the specimens was ∼10% of the top value. This study demonstrated that LCU beam profiles were non‐uniform in the area explored. Localized differences in DC and %KH reduction existed throughout the RMC specimens but did not follow a specific pattern. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1496–1504, 2018.
The colonic groove of the plains viscacha (Lagostomus maximus): Histochemical evidence of an abrupt change in the glycosylation pattern of goblet cells
Authors: Tano de la Hoz María Florencia , Flamini Mirta Alicia , Zanuzzi Carolina Natalia , Díaz Alcira Ofelia 
Published: July 2017

AbstractThe ascending colon of most rodent species shows a longitudinal colonic groove that works as a retrograde transport pathway for a mixture of bacteria and mucus toward the cecum. We describe the morphology and glycosylation pattern of the colonic groove of Lagostomus maximus to analyze the role of mucins in this anatomical feature. We also studied the distribution pattern of the interstitial cells of Cajal (ICC) to evaluate their regulatory influence on gut motility. The groove originated near the cecocolic junction and extended along the mesenteric side of the ascending colon, limited at both ends by nonpapillated ridges. These ridges divided the lumen of the ascending colon into two compartments: a narrow channel and a large channel, called the groove lumen and the main lumen, respectively. The histochemical analysis showed differences in the glycosylation pattern of the goblet cells inside and outside the groove. Unlike the mucosa lining the main lumen of the colon, the groove was rich in goblet cells that secrete sulfomucins. The PA/Bh/KOH/PAS technique evidenced an abrupt change in the histochemical profile of goblet cells, which presented a negative reaction in the groove and a strongly positive one in the rest of the colonic mucosa. The anti‐c‐kit immunohistochemical analysis showed different ICC subpopulations in the ascending colon of L. maximus. Of all types identified, the ICC‐SM were the only cells located solely within the colonic groove.