bluuebunny/crossref_metadata_2025 huggingface dataset:
Cross‐sectional structural variation relative to midshaft along hominine diaphyses. II. The hind limb
Authors: Mongle Carrie S. , Wallace Ian J. , Grine Frederick E.
Published: July 2015

Objectives

In comparative analyses of hominine hind limb diaphyseal structure, homologous cross sections are located according to half bone length (midshaft). Here, we address three questions. First, how accurately must midshaft be defined to yield comparable data? Second, does variation in midshaft location due to different ways of measuring length fall within error ranges such that data gathered using different metrics are comparable? Third, do error ranges and length metric effects differ between elements or taxa such that certain bones or species are more prone to issues of comparability?

Materials and Methods

Femora and tibiae of Homo, Pan, and Gorilla were CT‐scanned longitudinally and error ranges for multiple structural parameters (CSA, J, Imax/Imin) were calculated around midshafts.

Results

Distances proximally and distally from midshaft where structural values differ significantly from midshaft values vary between bones, species, and structural traits. Femoral error ranges are typically larger than tibial ranges. In the femur, error ranges are generally largest for chimpanzees and smallest for gorillas. A similar taxonomic pattern is not evident in the tibia. No structural trait consistently displays larger or smaller error ranges across both elements and all species. Variation in midshaft locations stemming from different length definitions is small and falls within observed error ranges defined by any one metric.

Discussion

Incorporating fragmentary specimens (e.g., fossils) for which midshaft location is unknown in comparisons of diaphyseal structure necessitates evaluation on a case‐by‐case basis, with thought to element, taxon, and structural traits of interest. Midshaft data recorded from distinct length measurements are generally comparable. Am J Phys Anthropol 158:398–407, 2015. © 2015 Wiley Periodicals, Inc.
Application of a CC Bond‐Forming Conjugate Addition Reaction in Asymmetric Dearomatization of β‐Naphthols
Authors: Yang Dongxu , Wang Linqing , Kai Ming , Li Dan , Yao Xiaojun , Wang Rui
Published: July 2015

A CC bond‐forming conjugate reaction was successfully applied to the enantioselective dearomatization of β‐naphthols. A C(sp2)C(sp3) bond is formed by using propargylic ketones as reactive partners. Good to excellent Z/E ratios and ee values were obtained by employing an in situ generated magnesium catalyst. Further transformations of the Z‐configured CC double bond in the products were achieved under mild reaction conditions. Moreover, the stereocontrolling element of this magnesium‐catalyzed dearomatization reaction was explored by computational chemistry.
Aromatic Gain in a Supramolecular Polymer
Authors: Saez Talens Victorio , Englebienne Pablo , Trinh Thuat T. , Noteborn Willem E. M. , Voets Ilja K. , Kieltyka Roxanne E.
Published: July 2015

The synergy of aromatic gain and hydrogen bonding in a supramolecular polymer is explored. Partially aromatic bis(squaramide) bolaamphiphiles were designed to self‐assemble through a combination of hydrophobic, hydrogen‐bonding, and aromatic effects into stiff, high‐aspect‐ratio fibers. UV and IR spectroscopy show electron delocalization and geometric changes within the squaramide ring indicative of strong hydrogen bonding and aromatic gain of the monomer units. The aromatic contribution to the interaction energy was further supported computationally by nucleus‐independent chemical shift (NICS) and harmonic oscillator model of aromaticity (HOMA) indices, demonstrating greater aromatic character upon polymerization: at least 30 % in a pentamer. The aromatic gain–hydrogen bonding synergy results in a significant increase in thermodynamic stability and a striking difference in aggregate morphology of the bis(squaramide) bolamphiphile compared to isosteres that cannot engage in this effect.
Photoexcited Porphyrins as a Strong Suppressor of β‐Amyloid Aggregation and Synaptic Toxicity
Authors: Lee Byung Il , Lee Seongsoo , Suh Yoon Seok , Lee Joon Seok , Kim Ae‐kyeong , Kwon O‐Yu , Yu Kweon , Park Chan Beum
Published: July 2015

The abnormal assembly of β‐amyloid (Aβ) peptides into neurotoxic, β‐sheet‐rich amyloid aggregates is a major pathological hallmark of Alzheimer’s disease (AD). Light‐induced photosensitizing molecules can regulate Aβ amyloidogenesis. Multiple photochemical analyses using circular dichroism, atomic force microscopy, dot blot, and native gel electrophoresis verified that photoactivated meso‐tetra(4‐sulfonatophenyl)porphyrin (TPPS with M=2H+, Zn2+, Cu2+, Mn2+) successfully inhibits Aβ aggregation in vitro. Furthermore, Aβ toxicity was relieved in the photoexcited‐TPPS‐treated Drosophila AD model. TPPS suppresses neural cell death, synaptic toxicity, and behavioral defects in the Drosophila AD model under blue light illumination. Behavioral phenotypes, including larval locomotion defect and short lifespan caused by Aβ overexpression, were also rescued by blue light‐excited TPPS.
Rhodium(III)‐Catalyzed Activation of CH Bonds and Subsequent Intermolecular Amidation at Room Temperature
Authors: Huang Xiaolei , Wang Yan , Lan Jingbo , You Jingsong
Published: July 2015

Disclosed herein is a RhIII‐catalyzed chelation‐assisted activation of unreactive CH bonds, thus enabling an intermolecular amidation to provide a practical and step‐economic route to 2‐(pyridin‐2‐yl)ethanamine derivatives. Substrates with other N‐donor groups are also compatible with the amidation. This protocol proceeds at room temperature, has a relatively broad functional‐group tolerance and high selectivity, and demonstrates the potential of rhodium(III) in the promotive functionalization of unreactive CH bonds. A rhodacycle having a SbF6− counterion was identified as a plausible intermediate.
An Aligned and Laminated Nanostructured Carbon Hybrid Cathode for High‐Performance Lithium–Sulfur Batteries
Authors: Sun Qian , Fang Xin , Weng Wei , Deng Jue , Chen Peining , Ren Jing , Guan Guozhen , Wang Min , Peng Huisheng
Published: July 2015

An aligned and laminated sulfur‐absorbed mesoporous carbon/carbon nanotube (CNT) hybrid cathode has been developed for lithium–sulfur batteries with high performance. The mesoporous carbon acts as sulfur host and suppresses the diffusion of polysulfide, while the CNT network anchors the sulfur‐absorbed mesoporous carbon particles, providing pathways for rapid electron transport, alleviating polysulfide migration and enabling a high flexibility. The resulting lithium–sulfur battery delivers a high capacity of 1226 mAh g−1 and achieves a capacity retention of 75 % after 100 cycles at 0.1 C. Moreover, a high capacity of nearly 900 mAh g−1 is obtained for 20 mg cm−2, which is the highest sulfur load to the best of our knowledge. More importantly, the aligned and laminated hybrid cathode endows the battery with high flexibility and its electrochemical performances are well maintained under bending and after being folded for 500 times.
Selective Alcohol Oxidation by a Copper TEMPO Catalyst: Mechanistic Insights by Simultaneously Coupled Operando EPR/UV‐Vis/ATR‐IR Spectroscopy
Authors: Rabeah Jabor , Bentrup Ursula , Stößer Reinhard , Brückner Angelika
Published: July 2015

The first coupled operando EPR/UV‐Vis/ATR‐IR spectroscopy setup for mechanistic studies of gas‐liquid phase reactions is presented and exemplarily applied to the well‐known copper/TEMPO‐catalyzed (TEMPO=(2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl) oxidation of benzyl alcohol. In contrast to previous proposals, no direct redox reaction between TEMPO and CuI/CuII has been detected. Instead, the role of TEMPO is postulated to be the stabilization of a (bpy)(NMI)CuII‐O2⋅−‐TEMPO (bpy=2,2′‐bipyridine, NMI=N‐methylimidazole) intermediate formed by electron transfer from CuI to molecular O2.
Nannocystin A: an Elongation Factor 1 Inhibitor from Myxobacteria with Differential Anti‐Cancer Properties
Authors: Krastel Philipp , Roggo Silvio , Schirle Markus , Ross Nathan T. , Perruccio Francesca , Aspesi Peter , Aust Thomas , Buntin Kathrin , Estoppey David , Liechty Brigitta , Mapa Felipa , Memmert Klaus , Miller Howard , Pan Xuewen , Riedl Ralph , Thibaut Christian , Thomas Jason , Wagner Trixie , Weber Eric , Xie Xiaobing , Schmitt Esther K. , Hoepfner Dominic
Published: July 2015

Cultivation of myxobacteria of the Nannocystis genus led to the isolation and structure elucidation of a class of novel cyclic lactone inhibitors of elongation factor 1. Whole genome sequence analysis and annotation enabled identification of the putative biosynthetic cluster and synthesis process. In biological assays the compounds displayed anti‐fungal and cytotoxic activity. Combined genetic and proteomic approaches identified the eukaryotic translation elongation factor 1α (EF‐1α) as the primary target for this compound class. Nannocystin A (1) displayed differential activity across various cancer cell lines and EEF1A1 expression levels appear to be the main differentiating factor. Biochemical and genetic evidence support an overlapping binding site of 1 with the anti‐cancer compound didemnin B on EF‐1α. This myxobacterial chemotype thus offers an interesting starting point for further investigations of the potential of therapeutics targeting elongation factor 1.
In vitro hydrolysis and magnesium release of poly(d,l‐lactide‐co‐glycolide)‐based composites containing bioresorbable glasses and magnesium hydroxide
Authors: Uppstu Peter , Paakki Charlotta , Rosling Ari
Published: July 2015

Magnesium is important for both bone growth and cartilage formation. However, the postoperative intake of antibiotics such as quinolones may cause a reduction in magnesium levels in tissue. The addition of magnesium to scaffolds may therefore be beneficial for the regeneration of osteochondral defects. In this study, porous composite scaffolds were produced by gas foaming of poly(d,l‐lactide‐co‐glycolide) (PLGA) rods with magnesium‐containing bioresorbable glasses and magnesium hydroxide as fillers. The in vitro hydrolytical degradation of the composite scaffolds in Tris buffer was followed over a 10‐week period. Mg2+ was released in a controlled manner from the scaffolds with varying release profiles between the different materials. Higher glass content resulted in a reduced mass loss compared to scaffolds with lower glass content. As a result of the foaming method, the scaffolds shrank initially, without evidence that the addition of hydrophilic fillers would decrease the initial shrinkage. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42646.
The Investigation of the Ardales Cave, Spain – 3D Documentation, Topographic Analyses, and Lighting Simulations based on Terrestrial Laser Scanning
Authors: Hoffmeister Dirk , Zellmann Stefan , Pastoors Andreas , Kehl Martin , Cantalejo Pedro , Ramos José , Weniger Gerd‐Christian , Bareth Georg
Published: July 2015

This contribution shows the application of terrestrial laser scanning in an integrative approach for the documentation and analyses of the Ardales Cave, southern Spain, which is in many respects an important geoarchaeological site. For the survey of the cave, a combination of the Riegl LMS Z420i laser scanner with a real‐time kinematic global positioning system (RTK‐GPS) from Topcon and further tachymetric measurements were used. The achieved three‐dimensional (3D) model of the cave and the surrounding hill documents the current topography and dimensions of the cave. Additional geoarchaeological data were successfully integrated in a 3D geographical information system (GIS) database and high‐resolution records of a structured‐light scanner were combined with the 3D model of the cave. The 3D model is further used for the estimation of the ceiling thickness that reveals areas for additional entrances. Lighting simulations based on path tracing were conducted for the determination of areas that are reached by natural direct or indirect light. In this case, the weight and size of the instrument was a logistic constraint to reach certain areas and to achieve a complete model of the cave. Overall, the method is feasible for the documentation of this cave and the investigations based on the derived 3D models. Copyright © 2015 John Wiley & Sons, Ltd.
IMAC capture of recombinant protein from unclarified mammalian cell feed streams
Authors: Kinna Alexander , Tolner Berend , Rota Enrique Miranda , Titchener‐Hooker Nigel , Nesbeth Darren , Chester Kerry
Published: July 2015

Fusion‐tag affinity chromatography is a key technique in recombinant protein purification. Current methods for protein recovery from mammalian cells are hampered by the need for feed stream clarification. We have developed a method for direct capture using immobilized metal affinity chromatography (IMAC) of hexahistidine (His6) tagged proteins from unclarified mammalian cell feed streams. The process employs radial flow chromatography with 300–500 μm diameter agarose resin beads that allow free passage of cells but capture His‐tagged proteins from the feed stream; circumventing expensive and cumbersome centrifugation and/or filtration steps. The method is exemplified by Chinese Hamster Ovary (CHO) cell expression and subsequent recovery of recombinant His‐tagged carcinoembryonic antigen (CEA); a heavily glycosylated and clinically relevant protein. Despite operating at a high NaCl concentration necessary for IMAC binding, cells remained over 96% viable after passage through the column with host cell proteases and DNA detected at ∼8 U/mL and 2 ng/μL in column flow‐through, respectively. Recovery of His‐tagged CEA from unclarified feed yielded 71% product recovery. This work provides a basis for direct primary capture of fully glycosylated recombinant proteins from unclarified mammalian cell feed streams. Biotechnol. Bioeng. 2016;113: 130–140. © 2015 Wiley Periodicals, Inc.
Pharmacokinetic study of ofloxacin enantiomers in Pagrosomus major by chiral HPLC
Authors: Nie Jing , Wang Yang–Guang , Gao Xiao–Feng , OuYang Xiao–kun , Yang Li–Ye , Yu Di , Wu Wei–jian , Xu Hong–Ping
Published: July 2015

(S)‐(−)‐Ofloxacin and (R)‐(+)‐ofloxacin concentrations in the plasma of Pagrosomus major after drug treatment were detected by chiral high‐performance liquid chromatography, and various pharmacokinetic parameters were calculated from these data. The elimination half‐life of (S)‐(−)‐ofloxacin was significantly shorter than that of the (R)‐(+) enantiomer. (S)‐(−)‐Ofloxacin also had a significantly lower maximum plasma concentration, area under the concentration–time curve from zero to infinity, and mean residence time than (R)‐(+)‐ofloxacin. However, the apparent volume of distribution and total body clearance of (S)‐(−)‐ofloxacin were greater than those of (R)‐(+)‐ofloxacin. The ratio of the (S)‐(−)‐ to (R)‐(+)‐ofloxacin plasma concentration was always <1.0. Together, these data suggest that (S)‐(−)‐ofloxacin was preferentially excreted and (R)‐(+)‐ofloxacin was preferentially absorbed. Although the difference in pharmacokinetic parameters was small, the metabolic behavior of the ofloxacin enantiomers in P. major was enantioselective. Copyright © 2015 John Wiley & Sons, Ltd.
Getting back together after a break‐up: Relationship advice for anatomists and surgeons
Authors: Phitayakorn Roy , Lachman Nirusha
Published: July 2015

The “surgeon‐anatomist” was originally a single individual who self‐pursued knowledge and understanding of anatomy as the foundation for successful surgical outcomes. However, recent advances in medical education have ironically led to the separation of anatomy and surgery. This physical and emotional “divorce” of anatomists and surgeons into separate individuals has created several critical educational issues for medical and surgical educators including a general lack of anatomical knowledge in medical students and misalignment of graduate medical education procedural specialty training with the Accreditation Council of Graduate Medical Education Core Competencies and now the Next Accreditation System. There are numerous opportunities for anatomists and surgeons to work together to improve educational instruction of established difficult anatomical regions, procedural training, or even develop new techniques and procedures. Similarly, anatomists with specialized training in medical education would be invaluable partners to ensure that procedural assessments align with instructional technologies for truly longitudinal curricula that starts at the medical student level, but stops at the patient outcomes of attending surgeons. This mutually beneficial relationship would be similar to multidisciplinary care teams and current surgeon and PhD/EdD partnerships. The restoration of the relationship between anatomists and surgeons would be invaluable to surgical education and remains an exciting research opportunity. Clin. Anat. 28:931–934, 2015. © 2015 Wiley Periodicals, Inc.
Origin of the right coronary artery from the opposite sinus of Valsalva in adults: Characterization by intravascular ultrasonography at baseline and after stent angioplasty
Authors: Angelini Paolo , Uribe Carlo , Monge Jorge , Tobis Jonathan M. , Elayda MacArthur A. , Willerson James T.
Published: July 2015

Objectives

We attempted to characterize the anatomy, function, clinical consequences, and treatment of right‐sided anomalous coronary artery origin from the opposite side (R‐ACAOS).

Background

Anomalous aortic origin of a coronary artery is a source of great uncertainty in cardiology. A recent study by our group found that ACAOS had a high prevalence (0.48%) in a general population of adolescents.

Methods

Sixty‐seven consecutive patients were diagnosed with R‐ACAOS according to a new definition: ectopic right coronary artery (RCA) with an intramural proximal course. We used intravascular ultrasonograms of the RCA to quantify congenital stenosis (in patients with potentially serious clinical presentations), and we correlated these measurements with clinical manifestations.

Results

All patients had some proximal intramural stenosis (mean 50%, range 16–83% of the cross‐sectional area). Forty‐two patients (62%) underwent stent‐percutaneous coronary intervention (PCI) of R‐ACAOS because of significant symptoms, positive stress tests, and/or significant stenosis. Stent‐PCI was successful in all cases and correlated with improved symptoms at >1‐year follow‐up in 30 patients (71%) who were available for clinical follow‐up. No ACAOS‐related deaths occurred. The instent restenosis rate was 4/30 (13%) at a mean follow‐up time of 5.0 years.

Conclusions

This preliminary, but large and unprecedented observational study shows that cases angiographically identified as R‐ACAOS universally feature an intramural aortic course but only occasionally severe stenosis on resting IVUS imaging. Our data suggest that stent‐PCI with IVUS monitoring ameliorates patients’ presenting symptoms. © 2015 Wiley Periodicals, Inc.
Plerixafor as a salvage mobilization strategy for haploidentical peripheral blood allogeneic stem cell transplantation
Authors: Nadeau Michelle , George Laeth , Yeager Andrew M. , Anwer Faiz , McBride Ali
Published: July 2015

Key Clinical Message

In allogeneic stem cell mobilization, peripheral blood stem cell mobilization with filgrastim can be considered standard of care. Poor mobilizers may be at risk for inadequate stem cell collection during apheresis. He we present a successful case of salvage plerixafor use with filgrastim in a haploidentical identical transplant patient.
ReDrop – A Simulation Tool for the Design of Extraction Columns Based on Single‐Drop Experiments
Authors: Ayesterán José , Kopriwa Nicole , Buchbender Florian , Kalem Murat , Pfennig Andreas
Published: July 2015

The design of extraction columns based on information from lab experiments and appropriate simulation tools allows reduction of time and costs compared to conventional design methods using pilot‐plant experiments. For this purpose, the behavior of drops and drop swarms is investigated in lab‐scale experiments in order to create mathematical models containing system‐specific parameters that have to be fitted to those experiments. These models are implemented in a simulation program that solves drop‐population balances in extraction columns. At AVT‐Thermal Process Engineering of the RWTH Aachen University this concept was implemented in the program ReDrop. ReDrop can predict the separation performance and flooding point of pulsed sieve tray and structured as well as random‐packing extraction columns for standard and technical systems. The program has successfully been extended to columns with rotating internals.
Chemical Modification of Graphene Oxide through Diazonium Chemistry and Its Influence on the Structure–Property Relationships of Graphene Oxide–Iron Oxide Nanocomposites
Authors: Rebuttini Valentina , Fazio Enza , Santangelo Saveria , Neri Fortunato , Caputo Gianvito , Martin Cédric , Brousse Thierry , Favier Frédéric , Pinna Nicola
Published: July 2015

4‐Carboxyphenyl groups are covalently grafted onto graphene oxide via diazonium chemistry for studying their role on the adsorption of iron oxide nanoparticles. The nanoparticles are deposited via a novel phase‐transfer approach involving specific interactions at the interface between two immiscible solvents. The increased density and the homogeneous distribution of surface carboxyl moieties enable the preparation of a nanocomposite with improved iron oxide distribution and loading. Structure‐properties relationships are investigated by analysing the electrochemical properties of the nanocomposites, which are regarded as promising active materials for application in supercapacitors. It is demonstrated that the nature of the interactions between the components similarly affects the overall electrochemical performances of the nanocomposites and the structure of the materials.
Advancing Nanochemistry Education
Authors: Pagliaro Mario
Published: July 2015

The chemical approach to nanotechnology that has emerged in the last three decades has proved to be extremely fertile. As chemistry increasingly turns into nanochemistry, and renewable solar energy available in sunlight and in biomass emerges as the main energy and raw materials source available to mankind, effective teaching of nanochemistry becomes increasingly important. This Viewpoint identifies the requirements of a short course aimed to provide future scholars with the conceptual foundations, and a clear perspective, of an important discipline which turned out to be the enabler of nanotechnology.
Stereoselective Synthesis of Highly Functionalized Hydroindoles as Building Blocks for Rostratins B–D and Synthesis of the Pentacyclic Core of Rostratin C
Authors: Zhong Sabilla , Sauter Paul F. , Nieger Martin , Bräse Stefan
Published: July 2015

The stereoselective synthesis of a variety of functionalized hydroindoles suitable as building blocks for thiodiketopiperazine natural products such as rostratins B–D is reported. The key precursor for all transformations is a previously reported hexahydroindole compound. All functional groups were installed with the desired stereochemistry and the feasibility of the synthetic strategy was exemplified by dimerization of two hydroindole units to form the pentacyclic C2‐symmetric scaffold of rostratin C.
Monitoring Glycan–Protein Interactions by NMR Spectroscopic Analysis: A Simple Chemical Tag That Mimics Natural CH–π Interactions
Authors: Calle Luis P. , Echeverria Begoña , Franconetti Antonio , Serna Sonia , Fernández‐Alonso M. Carmen , Diercks Tammo , Cañada F. Javier , Ardá Ana , Reichardt Niels‐Christian , Jiménez‐Barbero Jesús
Published: July 2015

Detection of molecular recognition processes requires robust, specific, and easily implementable sensing methods, especially for screening applications. Here, we propose the difluoroacetamide moiety (an acetamide bioisoster) as a novel tag for detecting by NMR analysis those glycan–protein interactions that involve N‐acetylated sugars. Although difluoroacetamide has been used previously as a substituent in medicinal chemistry, here we employ it as a specific sensor to monitor interactions between GlcNAc‐containing glycans and a model lectin (wheat germ agglutinin). In contrast to the widely employed trifluoroacetamide group, the difluoroacetamide tag contains geminal 1H and 19F atoms that allow both 1H and 19F NMR methods for easy and robust detection of molecular recognition processes involving GlcNAc‐ (or GalNAc‐) moieties over a range of binding affinities. The CHF2CONH‐ moiety behaves in a manner that is very similar to that of the natural acetamide fragment in the involved aromatic‐sugar interactions, providing analogous binding energy and conformations, whereas the perfluorinated CF3CONH‐ analogue differs more significantly.
Synthesis of BiOClxBr1−x Nanoplate Solid Solutions as a Robust Photocatalyst with Tunable Band Structure
Authors: Zhang Xing , Wang Li‐Wei , Wang Chu‐Ya , Wang Wei‐Kang , Chen Ya‐Li , Huang Yu‐Xi , Li Wen‐Wei , Feng Yu‐Jie , Yu Han‐Qing
Published: July 2015

The use of bismuth oxyhalides as photocatalysts has received extensive interest because of their high photocatalytic activity and stability. However, available methods for the synthesis of bismuth oxyhalides with tailored morphologies, well‐defined facets, and tunable band gaps are still lacking. In this work, two‐dimensional BiOClxBr1−x solid solution with exposed {001} facets and tunable band gaps were synthesized by using solvothermal methods. The BiOClxBr1−x solid solution nanoplates crystallized in a homogeneous crystal structure but possessed continuously tuned band gaps from 3.39 to 2.78 eV by decreasing the ratio of Cl/Br. Among the synthesized nanoplates, the BiOCl0.5Br0.5 sample exhibited the highest photocatalytic activity for degrading Rhodamine B (RhB), a typical organic pollutant, under visible light. The highest photoactivity of the BiOCl0.5Br0.5 sample was attributed to a synergetic effect of higher surface area, facets exposed, and optimized band structure. The results are of profound significance for the design of novel photocatalyst materials.
Color Tuning of the Aggregation‐Induced Emission of Maleimide Dyes by Molecular Design and Morphology Control
Authors: Imoto Hiroaki , Kizaki Kohei , Watase Seiji , Matsukawa Kimihiro , Naka Kensuke
Published: July 2015

Aggregation‐induced emission (AIE)‐active maleimide dyes, namely, 2‐p‐toluidino‐N‐p‐tolylmaleimide, 3‐phenyl‐2‐toluidino‐N‐p‐tolylmaleimide, 2‐p‐thiocresyl‐3‐p‐toluidino‐N‐p‐tolylmaleimide, and 2,3‐dithiocresyl‐N‐arylmaleimides, were synthesized by facile synthetic procedures. The dyes show intense emission in the solid state, and emission colors were controlled from green (λmax=527 nm) to orange (λmax=609 nm) by varying the substituents at the 2‐ and 3‐positions of the maleimide and the packing structures in the solid state. 2,3‐Disubstituted maleimide dyes effectively underwent redshifts of their emission wavelength. Furthermore, some of the dyes exhibited mechanochromism and polymorphism, and their emission properties were dramatically dependent on the morphology of the solid samples. The mechanisms of the emission behaviors were investigated by X‐ray diffraction. The substituent of the nitrogen atom of the maleimide ring affected the intermolecular interactions and short contacts, which were observed by single crystal X‐ray crystallography, to result in completely different emission properties.
Regiospecific Intermolecular Aminohydroxylation of Olefins by Photoredox Catalysis
Authors: Miyazawa Kazuki , Koike Takashi , Akita Munetaka
Published: July 2015

A simple and regiospecific aminohydroxylation of olefins by photoredox catalysis has been developed. N‐protected 1‐aminopyridinium salts are the key compounds and serve as amidyl radical precursors by the action of Ir photocatalysts, fac‐[Ir(ppy)3] and [Ir(ppy)2(dtbbpy)](PF6) (ppy=2‐pyridylphenyl, dtbbpy=4,4′‐di‐tert‐butyl‐2,2′‐bipyridine). The present photocatalytic system allows for synthesis of vicinal aminoalcohol derivatives from olefins with various functional groups under mild reaction conditions with easy handling.
Enantio‐ and Diastereoselective Formal Hetero‐Diels–Alder Reactions of Trifluoromethylated Enones Catalyzed by Chiral Primary Amines
Authors: Lin Yong‐Jun , Du Li‐Na , Kang Tai‐Ran , Liu Quan‐Zhong , Chen Ze‐Qin , He Long
Published: July 2015

Enantioselective formal hetero‐Diels‐Alder reactions of trifluoromethylated enones and 2‐amino‐1,3‐butadienes generated in situ from aliphatic acyclic enones and chiral primary amines are reported. The corresponding tetrahydropyran‐4‐ones are formed in up to 94 % yield and with up to 94 % ee. The reaction was carried out through a stepwise mechanism, including initial aminocatalytic aldol condensation of 2‐amino‐1,3‐butadiene to the trifluoromethylated carbonyl group followed by an intramolecular oxa‐Michael addition. Both NMR investigation and theoretical calculations on the transition state indicate that the protonated tertiary amine could effectively activate the carbonyl group of the trifluoromethyl ketone to promote the addition process through hydrogen‐bonding interaction of NH⋅⋅⋅F and NH⋅⋅⋅O simultaneously, and thus provide a chiral environment for the approach of amino‐1,3‐butadienes to the activated trifluoromethyl ketone, resulting in high enantioselectivity.
Self‐Assembly of Tyrosine into Controlled Supramolecular Nanostructures
Authors: Ménard‐Moyon Cécilia , Venkatesh V. , Krishna K. Vijaya , Bonachera Fanny , Verma Sandeep , Bianco Alberto
Published: July 2015

In the context of designing novel amino acid nanostructures, the capacity of tyrosine alone to form well‐ordered structures under different conditions was explored. It was observed that Tyr can self‐assemble into well‐defined morphologies when deposited onto surfaces for transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. The influence of various parameters that can modulate the self‐assembly process, including concentration of the amino acid, aging time, and solvent, was studied. Different supramolecular architectures, including nanoribbons, branched structures, and fern‐like arrangements were also observed.
A Stable Dimer of SiS2 Arranged between Two Carbene Molecules
Authors: Mohapatra Chandrajeet , Mondal Kartik Chandra , Samuel Prinson P. , Keil Helena , Niepötter Benedikt , Herbst‐Irmer Regine , Stalke Dietmar , Dutta Sayan , Koley Debasis , Roesky Herbert W.
Published: July 2015

The Me‐cAAC:‐stabilized dimer of silicon disulfide (SiS2) has been isolated in the molecular form as (Me‐cAAC:)2Si2S4 (2) at room temperature [Me‐cAAC:=cyclic alkyl(amino) carbene]. Compound 2 has been synthesized from the reaction of (Me‐cAAC:)2Si2 with elemental sulfur in a 1:4 molar ratio under oxidative addition. This is the smallest molecular unit of silicon disulfide characterized by X‐ray crystallography, electron ionization mass spectrometry, and NMR spectroscopy. Structures with three sulfur atoms arranged around a silicon atom are known; however, 2 is the first structurally characterized silicon–sulfur compound containing one terminal and two bridging sulfur atoms at each silicon atom. Compound 2 shows no decomposition after storing for three months in an inert atmosphere at ambient temperature. The bonding of 2 has been further studied by theoretical calculations.
Role of Hydrogen‐Bonding Acceptors in Organo‐Enamine Catalysis
Authors: Han Junbin , Lu Zhichao , Flach Andrew L. , Paton Robert S. , Hammond Gerald B. , Xu Bo
Published: July 2015

A hydrogen bond acceptor plays an important role in the catalytic cycle of organo‐enamine catalysis. It can effectively influence the rate of reaction through hydrogen bonding interaction with enammonium (N‐protonated enamine intermediate). Our findings are supported by both kinetic experiments and quantum chemical calculations.
Chiroptical Studies on Supramolecular Chirality of Molecular Aggregates
Authors: Sato Hisako , Yajima Tomoko , Yamagishi Akihiko
Published: July 2015

The attempts of applying chiroptical spectroscopy to supramolecular chirality are reviewed with a focus on vibrational circular dichroism (VCD). Examples were taken from gels, solids, and monolayers formed by low‐molecular mass weight chiral gelators. Particular attention was paid to a group of gelators with perfluoroalkyl chains. The effects of the helical conformation of the perfluoroalkyl chains on the formation of chiral architectures are reported. It is described how the conformation of a chiral gelator was determined by comparing the experimental and theoretical VCD spectra together with a model proposed for the molecular aggregation in fibrils. The results demonstrate the potential utility of the chiroptical method in analyzing organized chiral aggregates. Chirality 27:659–666, 2015. © 2015 Wiley Periodicals, Inc.
Kurt Gottlob – ein Leben für den Kautschuk
Authors: Röker Klaus‐Dieter
Published: July 2015

Der Chemiker Kurt Gottlob (1881–1925) war einer der bekanntesten Kautschuk‐Technologen des frühen 20. Jahrhunderts. Gottlobs Arbeiten deckten nahezu die gesamte Kautschukchemie ab. Kurt Gottlob war eines der wichtigsten und kreativsten Mitglieder im Arbeitskreis um Fritz Hofmann (1866–1956) bei den Farbenfabriken, vorm. Friedr. Bayer, welcher den Methylkautschuk, den weltweit ersten synthetischen Kautschuk, entwickelte. Zusammen mit Fritz Hofmann entdeckte er die organischen Beschleuniger, die den Vulkanisationsprozess des Kautschuks revolutionierten. Mit der Polymerisation von Isopren in Gegenwart von flüssigen kolloidalen Lösungen von Albumin wendete er erstmals das Prinzip der Emulsionspolymerisation an.
Enhancing fluidization stability and improving separation performance of fine lignite with vibrated gas‐solid fluidized bed
Authors: He Jingfeng , Zhao Yuemin , Zhao Jie , Luo Zhenfu , Duan Chenlong , He Yaqun
Published: July 2015

A vibrated gas‐solid fluidized bed was proposed and tested to improve and upgrade fine lignite. A broad particle size (0.074–0.3 mm) of magnetite powder was prepared and used as main separating medium solids for coal improvement. The fluidization stability of the bed, including the fluidization index, fluctuations of bed pressure drop, and uniformity of bed density, was greatly enhanced by introducing the vibration energy to the static bed. The vibrated separation shows positive effects to improve the surface morphology of lignite and upgrade its quality to a certain degree. Ash‐content segregation of fine lignite samples obviously occurs by the joint effects of fluidized gas and vibration. The optimal segregation degree Sash values of 0.73 and 0.70 were achieved with suitable operating factors. The density‐dependent separation performance indicates that the ash and sulfur contents of lignite were sharply reduced with the probable error E values of 0.060 and 0.065 g/cm3. However, the overall E value for 6–1 mm sized fine lignite increases to 0.12 g/cm3 due to the shift in the D50 with particle size. The products of low‐ash clean coal, middlings, and high‐ash gangue were effectively obtained by successive separations. The dry coal improvement technology provides an alternative approach for the clean utilization of fine coal.
Capillary force mediated flow patterns and non‐monotonic pressure drop characteristics of oil‐water microflows
Authors: Timung Seim , Tiwari Vijeet , Singh Amit Kumar , Mandal Tapas Kumar , Bandyopadhyay Dipankar
Published: July 2015

We report the capillary and frictional force mediated transitions of morphologies of an oil‐water flow inside a microchannel using experiments and computational fluid dynamic simulations. A number of steady and time‐periodic flow patterns were reported with the variations in the interfacial tension, exchange of inlets, flow ratio, and viscosity ratio of the phases. Transitions from slug to plug to droplet to stratified flow patterns were obtained by tuning the interfacial tension. Progressive reduction in the interfacial tension transformed big slugs into smaller plugs, plugs into droplets, and droplets into a stratified flow pattern. Interestingly, the simulations uncovered a non‐monotonic and nonlinear reduction in pressure drop with the decrease in interfacial tension. The change in the pressure drop was correlated to the variation in the slug, plug, or droplet frequency of water at the outlet. The variations in the pressure drop were also associated with the transition from dripping to jetting of water droplet ejection near the channel inlet. Apart from the interfacial tension, the viscosity stratification across the phases was also found to play an important role in converting the slug flow patterns into smaller plugs or droplets. The study also reports the parametric space in which the droplet flow patterns could be obtained inside a microchannel tuning the flow and viscosity ratios of the phases alongside the interfacial tension. The reported transitions of flow patterns and the pressure drop characteristics can be of significance in improving the efficiency of future microfluidic devices.
Simulation and experiment on transitional behaviours of multiphase flow in a hydrocyclone
Authors: Wang Chenxiang , Ji Chen , Zou Jun
Published: July 2015

This paper presents an investigation of transitional behaviours of multiphase flow in a hydrocyclone. The experiment and simulation results reveal the existence of two stages of the transition period of gas‐liquid flow. The numerical model combined with the large eddy simulation model (LES), the volume of fluid model (VOF), and the Lagrangian discrete phase model (DPM) approach is used to simulate the multiphase flow in a hydrocyclone. The applicability of this approach with a 2‐step simulation strategy has been verified by the close agreement between the calculated and measured flow fields. Particle motion upon entering the hydrocyclone indicates the separation mechanism of a hydrocyclone. Moreover, a parameter of the hydrocyclone, separation cycle timeTc, is proposed to describe the dynamic characteristics of the particle residence time.
Kinetics and thermodynamics of diquat removal from water using magnetic graphene oxide nanocomposite
Authors: Hao Yongmei , Wang Zhongkai , Gou Jiajia , Wang Zhongming
Published: July 2015

A graphene oxide nanocomposite (GO‐Fe3O4) was synthesized with a simple and low‐cost method. This nanocomposite was characterized by XRD, TEM, FT‐IR, TGA, and VSM. Spherical Fe3O4 nanoparticles with an average size of 10 nm were uniformly applied to the surface of graphene oxide sheets. GO‐Fe3O4 nanocomposite showed a superparamagnetic characteristic at room temperature and its saturation magnetization was 8.5 A · M2/kg. The adsorption behaviour of diquat at the surface of GO‐Fe3O4 was investigated, including effects of pH, temperature, and water matrix. The adsorption kinetics, thermodynamics, and adsorption isotherm were also examined. The adsorption was strongly dependent on pH. The adsorption process obeyed the pseudo‐second order kinetic model, and the rate‐determining step might be chemical sorption. The Langmuir adsorption isotherm model was applicable for describing the adsorption of diquat onto GO‐Fe3O4, and the adsorption capacity was 74.85 mg/g at room temperature. Thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic. Most importantly, the GO‐Fe3O4 could remove 96.6 % of diquat from a real water sample when the concentration of diquat is 20 mg/L.
Development of Small‐Molecule Cryptochrome Stabilizer Derivatives as Modulators of the Circadian Clock
Authors: Lee Jae Wook , Hirota Tsuyoshi , Kumar Anupriya , Kim Nam‐Jung , Irle Stephan , Kay Steve A.
Published: July 2015

Small‐molecule probes have been playing prominent roles in furthering our understanding of the molecular underpinnings of the circadian clock. We previously discovered a carbazole derivative, KL001 (N‐(3‐(9H‐carbazol‐9‐yl)‐2‐hydroxypropyl)‐N‐(furan‐2‐ylmethyl)methanesulfonamide), as a stabilizer of the clock protein cryptochrome (CRY). Herein we describe an extensive structure–activity relationship analysis of KL001 derivatives leading to the development of a highly active derivative: 2‐(9H‐carbazol‐9‐yl)‐N‐(2‐chloro‐6‐cyanophenyl)acetamide (KL044). Subsequent 3D‐QSAR analysis identified critical features of KL001 derivatives and provided a molecular‐level understanding of their interaction with CRY. The electron‐rich carbazole, amide/hydroxy linker, sulfonyl group, and electron‐withdrawing nitrile moieties contribute to greater biological activity. The hydrogen bonding interactions with Ser394 and His357 as well as stronger CH–π interactions with Trp290 make KL044 a better binder than KL001. KL044 lengthened the circadian period, repressed Per2 activity, and stabilized CRY in reporter assays with roughly tenfold higher potency than KL001. Altogether, KL044 is a powerful chemical tool to control the function of the circadian clock through its action on CRY.
Concentration‐independent MRI of pH with a dendrimer‐based pH‐responsive nanoprobe
Authors: Bhuiyan Mohammed P. I. , Aryal Madhava P. , Janic Branislava , Karki Kishor , Varma Nadimpalli R. S. , Ewing James R. , Arbab Ali S. , Ali Meser M.
Published: July 2015

The measurement of extracellular pH (pHe) has significant clinical value for pathological diagnoses and for monitoring the effects of pH‐altering therapies. One of the major problems of measuring pHe with a relaxation‐based MRI contrast agent is that the longitudinal relaxivity depends on both pH and the concentration of the agent, requiring the use of a second pH‐unresponsive agent to measure the concentration. Here we tested the feasibility of measuring pH with a relaxation‐based dendritic MRI contrast agent in a concentration‐independent manner at clinically relevant field strengths. The transverse and longitudinal relaxation times in solutions of the contrast agent (GdDOTA‐4AmP)44‐G5, a G5–PAMAM dendrimer‐based MRI contrast agent in water, were measured at 3 T and 7 T magnetic field strengths as a function of pH. At 3 T, longitudinal relaxivity (r1) increased from 7.91 to 9.65 mM−1 s−1 (on a per Gd3+ basis) on changing pH from 8.84 to 6.35. At 7 T, r1 relaxivity showed pH response, albeit at lower mean values; transverse relaxivity (r2) remained independent of pH and magnetic field strengths. The longitudinal relaxivity of (GdDOTA‐4AmP)44‐G5 exhibited a strong and reversible pH dependence. The ratio of relaxation rates R2/R1 also showed a linear relationship in a pH‐responsive manner, and this pH response was independent of the absolute concentration of (GdDOTA‐4AmP)44‐G5 agent. Importantly, the nanoprobe (GdDOTA‐4AmP)44‐G5 shows pH response in the range commonly found in the microenvironment of solid tumors. Copyright © 2015 John Wiley & Sons, Ltd.
Impact of long‐term tenofovir disoproxil fumarate on incidence of hepatocellular carcinoma in patients with chronic hepatitis B
Authors: Kim W. Ray , Loomba Rohit , Berg Thomas , Aguilar Schall Raul E. , Yee Leland J. , Dinh Phillip V. , Flaherty John F. , Martins Eduardo B. , Therneau Terry M. , Jacobson Ira , Fung Scott , Gurel Selim , Buti Maria , Marcellin Patrick
Published: July 2015

BACKGROUND

Efficacy trials have shown that antiviral therapy improves the outcomes of patients with chronic hepatitis B virus (HBV) infection. However, prospective data regarding the effect of antiviral therapy on the incidence of hepatocellular carcinoma (HCC), especially among patients without cirrhosis, are limited. The authors examined the impact of tenofovir disoproxil fumarate (TDF) on the incidence of HCC using a validated prediction model.

METHODS

The incidence of HCC in patients treated with TDF was obtained in the pivotal TDF registration studies after 384 weeks of follow‐up. The predicted risk of HCC in individual patients was calculated using the Risk Estimation for Hepatocellular Carcinoma in Chronic Hepatitis B (REACH‐B) model, which estimates HCC incidence for up to 10 years based on age, sex, alanine aminotransferase level, hepatitis B e antigen status, and HBV‐DNA. Standardized incidence ratios (SIRs) were calculated comparing the observed and predicted numbers of HCC cases in the study cohort.

RESULTS

Among 634 patients with evaluable baseline biopsies, 152 had cirrhosis (Ishak fibrosis score of 5 or 6) and 482 did not. During the 384 weeks of study, 14 cases of HCC were reported, with 4 occurring within the first year. The incidence of HCC was 0.37% per year in the study as a whole (0.28% among patients without cirrhosis and 0.65% among patients with cirrhosis). Among patients without cirrhosis, the observed incidence of HCC was significantly lower than predicted (SIR, 0.40; 95% confidence interval, 0.199‐0.795). The last HCC case in a patient with cirrhosis occurred around week 192 with an SIR of 0.51 (95% confidence interval, 0.231‐1.144) reported at week 384.

CONCLUSIONS

Based on the REACH‐B risk calculator, long‐term therapy with TDF was associated with a reduced incidence of HCC among patients without cirrhosis who met treatment criteria. Cancer 2015;121:3631–3638. © 2015 American Cancer Society.
Prediction of future hepatocellular carcinoma incidence in moderate to heavy alcohol drinkers with the FIB‐4 liver fibrosis index
Authors: Suh Beomseok , Yun Jae Moon , Park Sehhoon , Shin Dong Wook , Lee Tae Hoon , Yang Hyung‐Kook , Ahn Eunmi , Lee Hyejin , Park Jin Ho , Cho BeLong
Published: July 2015

BACKGROUND

Although heavy alcoholics are at heightened risk for hepatocellular carcinoma (HCC), there are no guidelines that recommend HCC screening for heavy alcoholics. This study investigated FIB‐4, a noninvasive and easily applicable liver fibrosis index, as a risk factor for HCC incidence among alcohol drinkers without viral hepatitis.

METHODS

This retrospective cohort study included 6661 generally healthy adults who were 30 years old or older, did not have chronic viral hepatitis, and visited Seoul National University Hospital for a general, routine health evaluation. The future HCC incidence was determined from National Health Insurance medical service claims data (median follow‐up, 6.2 years).

RESULTS

With adjustments for age, sex, body mass index, smoking, and alcohol, compared with subjects with FIB‐4 values less 1.00, subjects with FIB‐4 values greater than or equal to 1.75 and less than 2.10 and subjects with FIB‐4 values greater than or equal to 2.10 had adjusted hazard ratios (aHRs) of 5.18 (95% confidence interval [CI], 1.12‐24.00) and 13.63 (95% CI, 3.77‐49.33), respectively, for HCC incidence. This was heightened in subjects who drank more 30 g of alcohol per day: the aHRs were 8.39 (95% CI, 1.28‐54.87) and 16.58 (95% CI, 3.87‐71.04), respectively. FIB‐4 was shown to have a higher predictive value for HCC incidence than ultrasonographically detected liver cirrhosis (C‐index, 0.665 vs 0.527; P = .044).

CONCLUSIONS

High FIB‐4 is a risk factor with a high predictive value for HCC incidence, especially among moderate to heavy alcoholics (>30 g/d). FIB‐4 is a readily available and probably cost‐effective clinical tool with potential value for identifying subpopulations of alcoholics at particularly high risk who would benefit from regular HCC screening. Further investigations are warranted to validate our results; nonetheless, our study suggests that FIB‐4 may be useful in HCC screening among alcoholics. Cancer 2015;121:3818–3825. © 2015 American Cancer Society.
Asymptotic Behavior of the Nonlinear Schrödinger Equation with Harmonic Trapping
Authors: Hani Zaher , Thomann Laurent
Published: July 2015

We consider the cubic nonlinear Schrödinger equation with harmonic trapping on ℝD (1 ≤ D ≤ 5). In the case when all directions but one are trapped (aka “cigar‐shaped trap”), we prove modified scattering and construct modified wave operators for small initial and final data, respectively. The asymptotic behavior turns out to be a rather vigorous departure from linear scattering and is dictated by the resonant system of the NLS equation with full trapping on ℝD−1. In the physical dimension D = 3, this system turns out to be exactly the (CR) equation derived by Faou, Germain, and the first author as the large box limit of the resonant NLS equation in the homogeneous (zero potential) setting. The special dynamics of the latter equation, combined with the above modified scattering results, allow us to justify and extend some physical approximations in the theory of Bose‐Einstein condensates in cigar‐shaped traps.© 2016 Wiley Periodicals, Inc.