bluuebunny/crossref_metadata_2025 huggingface dataset:
Edge-Sensitive Semiconducting Behaviour in Low-Defect Narrow Graphene Nanoribbons
Authors: Kamikawa Syota , Shimizu Taisei , Yagi Yuko , Haruyama Junji
Published: April 2014

Low-defect graphene nanoribbons (GNRs) derived from the unzipping of carbon nanotubes have exhibited large energy band gaps (transport gaps), despite having widths in the order of ~100 nm. Here, we report on the unique semiconducting behaviour of very narrow, low-defect GNRs, with widths of less than 20 nm. Narrow GNRs are highly resistive, and additional annealing is required to reduce their resistivity. The GNRs display ambipolar rather than evident semiconducting behaviour (p- and n-types), exhibiting normalized Ion/ Ioff as great as ~106 (close to those in a few nm-order-width GNRs) and which are very sensitive to the atmosphere and the termination of the GNRs' edges by foreign atoms (hydrogen for n-type and oxygen for p-type). It is also revealed that the activation energy (Ea ~35 meV) estimated from the temperature dependence of the minimum conductance is smaller than those in ~100 nm width GNRs. The observed sharp conductance peak on back-gate voltage (Vbg) dependence and its strong correlation with the Ea value suggest the presence of possible resonant tunnelling through shallow impurity levels with the small Ea introduced by the edge terminations by foreign atoms, which provides the observed unique behaviour, including the high Ion/ Ioff. An energy band gap as large as ~215 meV is also confirmed from the Ioff voltage region on Vbg. These narrow GNRs must open the door to large-scale graphene integration circuits based on CMOS-like behaviour.
Porcine Skeletal Muscle-Derived Multipotent PW1pos/Pax7neg Interstitial Cells: Isolation, Characterization, and Long-Term Culture
Authors: Lewis Fiona C. , Henning Beverley J. , Marazzi Giovanna , Sassoon David , Ellison Georgina M. , Nadal-Ginard Bernardo
Published: April 2014

Developing effective strategies for the regeneration of solid tissue requires an understanding of the biology underlying the tissue's endogenous repair mechanisms. PW1/Peg3pos/Pax7neg skeletal muscle-derived interstitial progenitor cells (PICs) were first identified recently in the interstitium of murine skeletal muscle and shown to contribute to muscle fiber regeneration in vivo. PICs, therefore, represent a novel candidate resident progenitor cell for muscle regeneration. To explore the potential of these cells for clinical translation, we must ascertain the presence of PICs in larger mammalian species and identify criteria to successfully isolate and expand this population. In this study, we report the isolation, characterization, and maintenance of multipotent PICs from juvenile porcine skeletal muscle. We show that porcine PICs can be reproducibly isolated from skeletal muscle, express stem/progenitor cell markers, and have a stable phenotype and karyotype through multiple passages. Furthermore, porcine PICs are clonogenic and multipotent, giving rise to skeletal myoblast/myotubes, smooth muscle, and endothelial cells. In addition, PICs can be induced to differentiate into cardiomyocyte-like cells. These results demonstrate, in an animal model with size and physiology extrapolatable to the human, that porcine skeletal muscle-derived PW1pos/Pax7neg PICs are a source of stem/progenitor cells. These findings open new avenues for a variety of solid tissue engineering and regeneration using a single multipotent stem cell type isolated from an easily accessible source, such as skeletal muscle.
Malicious Peace: Violent Criminal Organizations, National Governments and Truces
Authors: Kan Paul Rexton
Published: April 2014

Truces among violent criminal organizations, like gangs and organized crime syndicates, which occur with national government support fall into a unique gap between understandings of crime and internal state violence. Recent national level gang truces in Central America and the Caribbean fall into this gap; the truces are designed to lower homicide rates and move some members of criminal groups towards legal activities. However, there is precious little research examining multiple truces in different countries as a group so that lessons may be drawn for other countries suffering from high levels of violence at the hands of criminal organizations. With violent criminal organizations as the main threat to the national security of many states, shedding light on how to reduce extreme levels of violence is vital. Close examination of attempted and implemented truces in Belize, El Salvador, Guatemala, Honduras and Trinidad and Tobago reveals that a constellation of factors leads national governments to be receptive to such agreements and violent criminal groups to accede to them.
Optimization of Ship Propulsion Diesel Engine to Fulfill the New Requirements for Exhaust Emissions
Authors: Lalić Branko , Komar Ivan , Nikolić Danilo
Published: April 2014

Impacts of exhaust gas emissions on the environment and air pollution from ships have received considerable attention in the past few decades. Due to the characteristics of the combustion process, typical for large marine two-stroke low-speed engines, and the use of residual fossil fuels, the world’s fleet emits into the atmosphere significant amount of pollutants such as nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide (CO2), hydrocarbons (HC), sulphur oxides (SOx) and carbon particles (PM). Impact assessment of the process of their formation, emitted amounts and the influence of emission are important factors for decision making in regulation development and also for engine designers who aim to improve low-speed two-stroke marine engines, for further tightening of regulations regarding limiting emissions. This paper consists of three parts: the first section describes the injection and combustion process in lowspeed two-stroke marine engines, the second part describes the formation of the exhaust as emissions as a product of the combustion process and the third part, in which the known techniques to reduce harmful emissions that are currently used in low-speed two-stroke marine engines are described.
Institute of Excepted Perils under the Rotterdam Rules 2009
Authors: Mandić Nikola
Published: April 2014

The Rotterdam Rules set forth, on the lines of the Hague-Visby Rules, a number of excepted perils when the carrier will not be liable for the damage to cargo. The institute of excepted perils was established by the Hague Rules almost 90 years ago, and is still implemented in practice. For such cases exceptionally the carrier is not liable under the principle of assumed guilty, but under the principle of proven guilty. In the preliminary activities for concluding the new international convention, the possibility has been considered of abolition of the institute of excepted perils has been considered, but in the end nevertheless, on the initiative of mainly maritime states, it has been retained, developed and more contemporarily styled, i.e. concerted with the requirements of the contemporary maritime transport. The Rotterdam Rules in Article 17, Paragraph 3, taxatively cite the excepted perils due to which the carrier will be able to exculpate from liability. The key difference is that error in navigation is no longer an excepted peril. Especially important novelties introduced by the Rotterdam Rules are exemption of the carrier from liability due to the acts of piracy, terrorist attacks, undertaking measures to avoid or prevent possible damage to the environment, and alike.
Palladium on Carbon‐Catalyzed One‐Pot N‐Arylindole Synthesis: Intramolecular Aromatic Amination, Aromatization, and Intermolecular Aromatic Amination
Authors: Monguchi Yasunari , Marumoto Takahisa , Takamatsu Haruki , Sawama Yoshinari , Sajiki Hironao
Published: April 2014

Indole and indoline derivatives were selectively and temperature dependently synthesized via the intramolecular cross‐coupling reaction between the amino and aromatic bromine functionalities of 2‐bromophenethylamine derivatives in the presence of 10% palladium on carbon (Pd/C), 1,1′‐bis(diphenylphosphino)ferrocene (DPPF), and sodium tert‐butoxide (NaO‐t‐Bu) in mesitylene at 140 and 200 °C, respectively. The neutralization using acetic acid after formation of the indoline derivatives effectively promoted their aromatization, and the corresponding indole derivatives were obtained at 140 °C. Furthermore, various aryl groups were also introduced to the N‐1 position of the indole, pyrrole, and carbazole rings by their direct intramolecular arylation with aryl halides and a one‐pot protocol for N‐arylindole synthesis from 2‐bromophenethylamine was developed.

magnified image
DNA Nanoflowers for Multiplexed Cellular Imaging and Traceable Targeted Drug Delivery
Authors: Hu Rong , Zhang Xiaobing , Zhao Zilong , Zhu Guizhi , Chen Tao , Fu Ting , Tan Weihong
Published: April 2014

We present a facile approach to make aptamer‐conjugated FRET (fluorescent resonance energy transfer) nanoflowers (NFs) through rolling circle replication for multiplexed cellular imaging and traceable targeted drug delivery. The NFs can exhibit multi‐fluorescence emissions by a single‐wavelength excitation as a result of the DNA matrix covalently incorporated with three dye molecules able to perform FRET. Compared with the conventional DNA nanostructure assembly, NF assembly is independent of template sequences, avoiding the otherwise complicated design of DNA building blocks assembled into nanostructures by base‐pairing. The NFs were uniform and exhibited high fluorescence intensity and excellent photostability. Combined with the ability of traceable targeted drug delivery, these colorful DNA NFs provide a novel system for applications in multiplex fluorescent cellular imaging, effective screening of drugs, and therapeutic protocol development.
A Biomimetic Catalytic Aerobic Functionalization of Phenols
Authors: Esguerra Kenneth Virgel N. , Fall Yacoub , Lumb Jean‐Philip
Published: April 2014

The importance of aromatic CO, CN, and CS bonds necessitates increasingly efficient strategies for their formation. Herein, we report a biomimetic approach that converts phenolic CH bonds into CO, CN, and CS bonds at the sole expense of reducing dioxygen (O2) to water (H2O). Our method hinges on a regio‐ and chemoselective copper‐catalyzed aerobic oxygenation to provide ortho‐quinones. ortho‐Quinones are versatile intermediates, whose direct catalytic aerobic synthesis from phenols enables a mild and efficient means of synthesizing polyfunctional aromatic rings.
Honoring our donors: A survey of memorial ceremonies in united states anatomy programs
Authors: Jones Trahern W. , Lachman Nirusha , Pawlina Wojciech
Published: April 2014

Many anatomy programs that incorporate dissection of donated human bodies hold memorial ceremonies of gratitude towards body donors. The content of these ceremonies may include learners' reflections on mortality, respect, altruism, and personal growth told through various humanities modalities. The task of planning is usually student‐ and faculty‐led with participation from other health care students. Objective information on current memorial ceremonies for body donors in anatomy programs in the United States appears to be lacking. The number of programs in the United States that currently plan these memorial ceremonies and information on trends in programs undertaking such ceremonies remain unknown. Gross anatomy program directors throughout the United States were contacted and asked to respond to a voluntary questionnaire on memorial ceremonies held at their institution. The results (response rate 68.2%) indicated that a majority of human anatomy programs (95.5%) hold memorial ceremonies. These ceremonies are, for the most part, student‐driven and nondenominational or secular in nature. Participants heavily rely upon speech, music, poetry, and written essays, with a small inclusion of other humanities modalities, such as dance or visual art, to explore a variety of themes during these ceremonies. Anat Sci Educ 7: 219–223. © 2013 American Association of Anatomists.
Dermal Developmental Toxicity of N‐Phenylimide Herbicides in Rats
Authors: Kawamura Satoshi , Kato Terushige , Nakaoka Masanao , Fantel Alan G.
Published: April 2014

Background

S‐53482 and S‐23121 are N‐phenylimide herbicides and produced embryolethality, teratogenicity (mainly ventricular septal defects and wavy ribs), and growth retardation in rats in conventional oral developmental toxicity studies. Our objective in this study was to investigate whether the compounds induce developmental toxicity via the dermal route, which is more relevant to occupational exposure, hence better addressing human health risks.

Methods

S‐53482 was administered dermally to rats at 30, 100, and 300 mg/kg during organogenesis, and S‐23121 was administered at 200, 400, and 800 mg/kg (the maximum applicable dose level). Fetuses were obtained by a Cesarean section and examined for external, visceral, and skeletal alterations.

Results

Dermal exposure of rats to S‐53482 at 300 mg/kg produced patterns of developmental toxicity similar to those resulting from oral exposure. Toxicity included embryolethality, teratogenicity, and growth retardation. Dermal administration of S‐23121 at 800 mg/kg resulted in an increased incidence of embryonic death and ventricular septal defect, but retarded fetal growth was not observed as it was following oral exposure to S‐23121.

Conclusions

Based on the results, S‐53482 and S‐23121 were teratogenic when administered dermally to pregnant rats as were the compounds administered orally. Thus, investigation of the mechanism and its human relevancy become more important.
Placental Transfer of a Fully Human IgG2 Monoclonal Antibody in the Cynomolgus Monkey, Rat, and Rabbit: A Comparative Assessment from during Organogenesis to Late Gestation
Authors: Moffat Graeme J. , Retter Marc W. , Kwon Gayle , Loomis Mark , Hock M. Benjamin , Hall Colin , Bussiere Jeanine , Lewis Elise M. , Chellman Gary J.
Published: April 2014

Understanding species differences in the placental transfer of monoclonal antibodies is important to inform species selection for nonclinical safety assessment, interpret embryo‐fetal changes observed in these studies, and extrapolate their human relevance. Data presented here for a fully human immunoglobulin G2 monoclonal antibody (IgG2X) revealed that, during organogenesis, in both the cynomolgus monkey (gestation day 35 [gd35]) and the rat (gd10) the extent of IgG2X placental transfer (approximately 0.5% maternal plasma concentration, MPC) was similar to the limited published human data for endogenous IgG. At this early gestational stage, IgG2X placental transfer was approximately 6‐fold higher in the rabbit (gd10). By the end of organogenesis, rat embryonic plasma concentrations (gd16) exceeded those in the cynomolgus monkey (gd50) by approximately 3‐fold. These data suggest that relative to the cynomolgus monkey, the rabbit (and to a lesser extent the rat) may overestimate potential harmful effects to the human embryo during this critical period of development. Beyond organogenesis, fetal IgG2X plasma concentrations increased approximately 10‐fold early in the second trimester (gd50–70) in the cynomolgus monkey and remained relatively unchanged thereafter (at approximately 5% MPC). Late gestational assessment was precluded in rabbits due to immunogenicity, but in rats, fetal IgG2X plasma concentrations increased more than 6‐fold from gd16 to gd21 (reaching approximately 15% MPC). In rats, maternal exposure consistent with that achieved by ICH S6(R1) high‐dose selection criteria resulted in embryonic plasma concentrations, reaching pharmacologically relevant levels during organogenesis. Furthermore, dose proportional exposure in both mothers and embryos indicated that this was unlikely to occur at the lower therapeutic dose levels used in humans
Effects of Macrolide Antibiotics on Rat Embryonic Heart Function In Vitro
Authors: Nilsson Mats F. , Webster William S.
Published: April 2014

The Swedish Medical Product Agency (MPA) has listed erythromycin as a suggested human teratogen, causing cardiovascular malformations. It is further suggested that this may be a class effect of macrolide antibiotics. The proposed teratogenic mechanism is blockade of the human ether‐á‐go‐go‐related (hERG)/IKr current in the embryonic heart causing bradycardia and arrhythmia resulting in altered cardiac blood flow and/or embryonic hypoxia. To test this hypothesis, we examined the effect of three macrolide antibiotics on the function of the rat embryonic heart. Gestational day 13 rat embryos in vitro were exposed to erythromycin (25–500 μM), clarithromycin (25–500 μM), or azithromycin (100 μM to 1 mM) for 3 hr. The effect on the embryonic heart was monitored every hour. The results showed that erythromycin and clarithromycin caused a concentration‐dependent bradycardia. Twenty‐five micromolar was a no‐effect concentration for erythromycin and was close to a no‐effect concentration for clarithromycin. Azithromycin only caused significant bradycardia at 1 mM. Additional studies were performed with the embryos cultured at 40°C instead of 38°C, to mimic fever. The increased temperature increased the number of arrhythmias but did not worsen the drug‐induced bradycardia. The results support the concept that erythromycin and clarithromycin can adversely affect the embryonic heart but only at concentrations well outside expected embryonic exposure in the human
Valve‐in‐valve implantation of a novel and small self‐expandable transcatheter heart valve in degenerated small surgical bioprostheses: The Hamburg experience
Authors: Diemert Patrick , Seiffert Moritz , Frerker Christian , Thielsen Thomas , Kreidel Felix , Bader Ralf , Schirmer Johannes , Conradi Lenard , Koschyk Dietmar , Schnabel Renate , Reichenspurner Hermann , Blankenberg Stefan , Kuck Karl‐Heinz , Treede Hendrik , Schaefer Ulrich
Published: April 2014

Background

Transcatheter valve‐in‐valve (VIV) implantation has emerged as a novel treatment option in patients with degenerated aortic bioprostheses and high surgical risk. However, VIV implantation in small aortic bioprostheses using first generation TAVI devices has frequently resulted in high postprocedural gradients and small effective orifice areas. Recently, an updated version of the self‐expandable Medtronic CoreValve prosthesis, which is particularly suitable for small aortic annuli, has become available. We report on the feasibility and early results of VIV implantation using this novel device in a series of patients with degenerated small aortic bioprostheses.

Methods and Results

16 patients from two Hamburg hospitals (age range 72–92 years) underwent implantation of a 23‐mm CoreValve Evolut (Medtronic, Minneapolis, MN, USA) transcatheter heart valve into failing aortic bioprostheses with internal diameters below 21 mm. All patients were considered high risk for surgical aortic valve replacement after evaluation by an interdisciplinary heart team mean (logistic EuroSCORE range 9.0–88%). Implantation was successful without relevant remaining aortic regurgitation or signs of stenosis and a marked reduction in postprocedural gradientswas observed in 14 out of 16 patients. The mean gradient was reduced from from 34 mm Hg (SEM 10 mm Hg) to 14 mm Hg (SEM 6 mm Hg). No major device‐ or procedure‐related adverse events occurred during 30‐day follow up and clinical improvement was observed.

Conclusions

Failing aortic bioprostheses with small internal diameters continue to be a challenging pathology for TAVI due to the risk of high residual gradients and small aortic orifice areas. This report provides first evidence that the 23‐mm CoreValve Evolut, a novel self‐expanding prosthesis, provides an improved treatment option in these specific patients due to its low profile which resulted in promising early results. © 2013 Wiley Periodicals, Inc.
Classical Hodgkin Lymphoma involving the central nervous system (brain) – an unusual presentation
Authors: van Blydenstein Sarah Alexandra , Patel Moosa , Philip Vinitha , Lakha Atul , Pather Sugeshnee , Westgarth‐Taylor Tracy , Thompson Eddison , Kolloori Avinash
Published: April 2014

Key Clinical Message

Intracranial Hodgkin lymphoma (HL) is considered so atypical that an intracranial space‐occupying lesion in a patient with known HL should be thoroughly investigated to rule out a second disease process.
From the Lindlar Catalyst to Supported Ligand‐Modified Palladium Nanoparticles: Selectivity Patterns and Accessibility Constraints in the Continuous‐Flow Three‐Phase Hydrogenation of Acetylenic Compounds
Authors: Vilé Gianvito , Almora‐Barrios Neyvis , Mitchell Sharon , López Núria , Pérez‐Ramírez Javier
Published: April 2014

Site modification and isolation through selective poisoning comprise an effective strategy to enhance the selectivity of palladium catalysts in the partial hydrogenation of triple bonds in acetylenic compounds. The recent emergence of supported hybrid materials matching the stereo‐ and chemoselectivity of the classical Lindlar catalyst holds promise to revolutionize palladium‐catalyzed hydrogenations, and will benefit from an in‐depth understanding of these new materials. In this work, we compare the performance of bare, lead‐poisoned, and ligand‐modified palladium catalysts in the hydrogenation of diverse alkynes. Catalytic tests, conducted in a continuous‐flow three‐phase reactor, coupled with theoretical calculations and characterization methods, enable elucidation of the structural origins of the observed selectivity patterns. Distinctions in the catalytic performance are correlated with the relative accessibility of the active site to the organic substrate, and with the adsorption configuration and strength, depending on the ensemble size and surface potentials. This explains the role of the ligand in the colloidally prepared catalysts in promoting superior performance in the hydrogenation of terminal and internal alkynes, and short‐chain alkynols. In contrast, the greater accessibility of the active surface of the Pd–Pb alloy and the absence of polar groups are shown to be favorable in the conversion of alkynes containing long aliphatic chains and/or ketone groups. These findings provide detailed insights for the advanced design of supported nanostructured catalysts.
Binuclear trans‐Bis(β‐iminoaryloxy)palladium(II) Complexes Doubly Linked with Pentamethylene Spacers: Structure‐Dependent Flapping Motion and Heterochiral Association Behavior of the Clothespin‐Shaped Molecules
Authors: Naito Masaya , Souda Hiroyuki , Koori Hiroshi , Komiya Naruyoshi , Naota Takeshi
Published: April 2014

The synthesis, structure, and solution‐state behavior of clothespin‐shaped binuclear trans‐bis(β‐iminoaryloxy)palladium(II) complexes doubly linked with pentamethylene spacers are described. Achiral syn and racemic anti isomers of complexes 1–3 were prepared by treating Pd(OAc)2 with the corresponding N,N′‐bis(β‐hydroxyarylmethylene)‐1,5‐pentanediamine and then subjecting the mixture to chromatographic separation. Optically pure (100 % ee) complexes, (+)‐anti‐1, (+)‐anti‐2, and (+)‐anti‐3, were obtained from the racemic mixture by employing a preparative HPLC system with a chiral column. The trans coordination and clothespin‐shaped structures with syn and anti conformations of these complexes have been unequivocally established by X‐ray diffraction studies. 1H NMR analysis showed that (±)‐anti‐1, (±)‐anti‐2, syn‐2, and (±)‐anti‐3 display a flapping motion by consecutive stacking association/dissociation between cofacial coordination planes in [D8]toluene, whereas syn‐1 and syn‐3 are static under the same conditions. The activation parameters for the flapping motion (ΔH≠ and ΔS≠) were determined from variable‐temperature NMR analyses as 50.4 kJ mol−1 and 60.1 J mol−1 K−1 for (±)‐anti‐1, 31.0 kJ mol−1 and −22.7 J mol−1 K−1 for (±)‐anti‐2, 29.6 kJ mol−1 and −57.7 J mol−1 K−1 for syn‐2, and 35.0 kJ mol−1 and 0.5 J mol−1 K−1 for (±)‐anti‐3, respectively. The molecular structure and kinetic parameters demonstrate that all of the anti complexes flap with a twisting motion in [D8]toluene, although (±)‐anti‐1 bearing dilated Z‐shaped blades moves more dynamically than I‐shaped (±)‐anti‐2 or the smaller (±)‐anti‐3. Highly symmetrical syn‐2 displays a much more static flapping motion, that is, in a see‐saw‐like manner. In CDCl3, (±)‐anti‐1 exhibits an extraordinary upfield shift of the 1H NMR signals with increasing concentration, whereas solutions of (+)‐anti‐1 and the other syn/anti analogues 2 and 3 exhibit negligible or slight changes in the chemical shifts under the same conditions, which indicates that anti‐1 undergoes a specific heterochiral association in the solution state. Equilibrium constants for the dimerizations of (±)‐ and (+)‐anti‐1 in CDCl3 at 293 K were estimated by curve‐fitting analysis of the 1H NMR chemical shift dependences on concentration as 26 M−1 [KD(racemic)] and 3.2 M−1 [KD(homo)], respectively. The heterochiral association constant [KD(hetero)] was estimated as 98 M−1, based on the relationship KD(racemic)=1/2 KD(homo)+1/4 KD(hetero). An inward stacking motif of interpenetrative dimer association is postulated as the mechanistic rationale for this rare case of heterochiral association.
DFT Simulations of Water Adsorption and Activation on Low‐Index α‐Ga2O3 Surfaces
Authors: Zhou Xin , Hensen Emiel J. M. , van Santen Rutger A. , Li Can
Published: April 2014

Density functional theory (DFT) calculations are used to explore water adsorption and activation on different α‐Ga2O3 surfaces, namely (001), (100), (110), and (012). The geometries and binding energies of molecular and dissociative adsorption are studied as a function of coverage. The simulations reveal that dissociative water adsorption on all the studied low‐index surfaces are thermodynamically favorable. Analysis of surface energies suggests that the most preferentially exposed surface is (012). The contribution of surface relaxation to the respective surface energies is significant. Calculations of electron local density of states indicate that the electron‐energy band gaps for the four investigated surfaces appears to be less related to the difference in coordinative unsaturation of the surface atoms, but rather to changes in the ionicity of the surface chemical bonds. The electrochemical computation is used to investigate the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) on α‐Ga2O3 surfaces. Our results indicate that the (100) and (110) surfaces, which have low stability, are the most favorable ones for HER and OER, respectively.
A Systematic Study of Peripherally Multiple Aromatic Ester‐Functionalized Poly(benzyl ether) Dendrons for the Fabrication of Organogels: Structure–Property Relationships and Thixotropic Property
Authors: Feng Yu , Liu Zhi‐Xiong , Chen Hui , Yan Zhi‐Chao , He Yan‐Mei , Liu Chen‐Yang , Fan Qing‐Hua
Published: April 2014

A new class of peripherally multiple aromatic ester‐functionalized poly(benzyl ether) dendrons and/or dendrimers with different focal point substituents, surface groups, interior structures, as well as different generations have been synthesized and their structure–property relationships with respect to their gelation ability have been investigated systematically. Most of these dendrons are able to gel organic solvents over a wide polarity range. Evident dendritic effects were observed not only in gelation capability but also in thermotropic, morphological, and rheological characterizations. It was disclosed that subtle changes in peripheral ester functionalities and interior dendritic structures affected the gelation behavior of the dendrons significantly. Among all the dendrons studied, the second‐ and third‐generation dendrons G0G2‐Me and G0G3‐Me with dimethyl isophthalates (DMIP) as peripheral groups exhibited the best capability in gelation, and stable gels were formed in more than 22 aromatic and polar organic solvents. The lowest critical gelation concentration (CGC) reached 2.0 mg mL−1, indicating that approximately 1.35×104 solvent molecules could be entrapped by one dendritic molecule. Further study on driving forces in gel formation was carried out by using a combination of single‐crystal/powder X‐ray diffraction (XRD) analysis and concentration‐dependent (CD)/temperature‐dependent (TD) 1H NMR spectroscopy. The results obtained from these experiments revealed that the multiple π–π stacking of extended π‐systems due to the peripheral DMIP rings, cooperatively assisted by non‐conventional hydrogen‐bonding, is the key contributor in the formation of the highly ordered supramolecular and fibrillar network. In addition, these dendritic organogels exhibited unexpected thixotropic‐responsive properties, which make them promising candidates with potential applications in the field of intelligent soft materials.
Solvothermal Transformation of a Calcium Oleate Precursor into Large‐Sized Highly Ordered Arrays of Ultralong Hydroxyapatite Microtubes
Authors: Lu Bing‐Qiang , Zhu Ying‐Jie , Chen Feng , Qi Chao , Zhao Xin‐Yu , Zhao Jing
Published: April 2014

Hydroxyapatite (HAP), a well‐known member of the calcium phosphate family, is the major inorganic component of bones and teeth in vertebrates. The highly ordered arrays of HAP structures are of great significance for hard tissue repair and for understanding the formation mechanisms of bones and teeth. However, the synthesis of highly ordered HAP structure arrays remains a great challenge. In this work, inspired by the ordered structure of tooth enamel, we have successfully synthesized three‐dimensional bulk materials with large sizes (millimeter scale) that are made of highly ordered arrays of ultralong HAP microtubes (HOAUHMs) by solvothermal transformation of calcium oleate precursor. The core–shell‐structured oblate sphere consists of a core that is composed of HAP nanorods and a shell that consists of highly ordered HAP microtube arrays. The prepared HOAUHMs are large: 6.0 mm in diameter and up to 1.4 mm in thickness. With increasing solvothermal reaction time, the HOAUHMs grow larger; the microtubes become more uniform and more ordered. This work provides a new synthetic method for synthesizing highly ordered arrays of uniform HAP ultralong microtubes that are promising for biomedical applications.
Nanostructured Graphene/TiO2 Hybrids as High‐Performance Anodes for Microbial Fuel Cells
Authors: Zhao Cui‐e , Wang Wen‐Jing , Sun Dong , Wang Xin , Zhang Jian‐Rong , Zhu Jun‐Jie
Published: April 2014

A new nanostructured graphene/TiO2 (G/TiO2) hybrid was synthesized by a facile microwave‐assisted solvothermal process in which amorphous TiO2 was assembled on graphene in situ. The resulting G/TiO2 hybrids were characterized by XRD, SEM, TEM, Raman spectroscopy, and N2 adsorption/desorption analysis. The electrochemical properties of the hybrids as anode materials for Shewanella‐inoculated microbial fuel cells (MFCs) were studied for the first time, and they proved to be effective in improving MFC performance. The significantly improved bacterial attachment and extracellular electron‐transfer efficiency could be attributed to the high specific surface area, active groups, large pore volume, and excellent conductivity of the nanostructured G/TiO2 hybrid, and this suggests that it could be a promising candidate for high‐performance MFCs.
Multicomponent, Flow Diazotization/Mizoroki–Heck Coupling Protocol: Dispelling Myths about Working with Diazonium Salts
Authors: Nalivela Kumara S. , Tilley Michael , McGuire Michael A. , Organ Michael G.
Published: April 2014

A single pass flow diazotization/Mizoroki–Heck protocol has been developed for the production of cinnimoyl and styryl products. The factors that govern aryl diazonium salt stability have been examined in detail leading to the development of a MeOH/DMF co‐solvent system in which the diazonium salts can be generated in the presence of all other reaction components and then coupled selectively to give the desired products. Finally the key role of the reaction quench for flow reactions has been demonstrated.
Photoinduced Intercalation and Coordination of a Dirhodium Complex to DNA: Dual DNA Binding
Authors: Palmer Alycia M. , Burya Scott J. , Gallucci Judith C. , Turro Claudia
Published: April 2014

Two new complexes, cis‐H,H‐[Rh2(OCCH3NH)2(LL)(CH3CN)2]2+, where LL=bpy (2, bpy=2,2′‐bipyridine) and dppz (3, dppz=dipyrido[3,2‐a:2′,3′‐c]phenazine), were prepared from the reaction of cis‐H,H‐[Rh2(OCCH3NH)2(CH3CN)6]2+ (1) with the corresponding bidentate ligand. The bpy and dppz ligands chelate to the same rhodium atom and are positioned trans to the amidato N atoms, as determined by the single crystal X‐ray structure of 2. Irradiation of 2 and 3 with visible light in water results in the exchange of one CH3CNeq ligand for an H2O molecule with quantum yields, Φ400, of 0.040 and 0.044, respectively (λirr=400 nm). The identities of the photoproducts of 2 and 3 were determined to be cis‐H,H‐[Rh2(OCCH3NH)2(L)(H2O)(CH3CN)]2+, where L is bpy (4) and dppz (5), respectively. Mobility shift assays show that 4 crosslinks double‐stranded DNA, and ESI‐MS experiments indicate that both 4 and 5 form covalent adducts with single‐stranded DNA. In addition, relative viscosity and 2D NMR experiments show that the dppz ligand of 5 also intercalates into DNA upon irradiation, making 3 a dual‐binding agent that both intercalates and covalently binds to DNA upon the absorption of visible light.
Surgical management of localized soft tissue tumors
Authors: Gronchi Alessandro , Colombo Chiara , Raut Chandrajit P.
Published: April 2014

Soft tissue tumors are rare and can arise from a variety of soft tissues and viscera in a variety of body sites. Their management requires a thorough understanding of the biology of the different histologies and molecular subtypes as well as the constraints of specific anatomic sites. The surgical approach has undergone significant changes thanks to a better understanding of the natural history of the different histologic subtypes, the importance of site, and the different sensitivity to available drugs. The soft tissue tumor family includes 3 major, distinct categories: desmoid‐type fibromatosis, soft tissue sarcoma, and gastrointestinal stromal tumor. In general, limb‐sparing and function‐sparing approaches should be used when feasible for tumors located in the extremities and girdles. Resections of adherent structures/viscera, which may be close but not invaded, may be needed in tumors arising in the retroperitoneum/abdomen to minimize microscopic intralesional margins, maximize local tumor control, and possibly improve survival. Margins of resection and the use of adjuvant/neadjuvant radiation therapy and/or chemotherapy are contingent on an accurate histologic diagnosis. Treatment planning should include multidisciplinary consultation to determine optimal therapy, taking into consideration tumor histology, site and extent of the disease, its natural history and sensitivity to available treatments, surgical challenges, and—of course—quality of life. Cancer 2014;120:2638–2648. © 2014 American Cancer Society.
Does Excited‐State Proton‐Transfer Reaction Contribute to the Emission Behaviour of 4‐Aminophthalimide in Aqueous Media?
Authors: Khara Dinesh Chandra , Banerjee Sanghamitra , Samanta Anunay
Published: April 2014

4‐Aminophthalimide (AP) is an extensively used molecule both for fundamental studies and applications primarily due to its highly solvent‐sensitive fluorescence properties. The fluorescence spectrum of AP in aqueous media was recently shown to be dependent on the excitation wavelength. A time‐dependent blue shift of its emission spectrum is also reported. On the basis of these findings, the excited‐state solvent‐mediated proton‐transfer reaction of the molecule, which was proposed once but discarded at a later stage, is reintroduced. We report on the fluorescence behaviour of AP and its imide‐H protected derivative, N‐BuAP, to prove that a solvent‐assisted excited‐state keto–enol transformation does not contribute to the steady‐state and time‐resolved emission behaviour of AP in aqueous media. Our results also reveal that the fluorescence of AP in aqueous media arises from two distinct hydrogen‐bonded species. The deuterium isotope effect on the fluorescence quantum yield and lifetime of AP, which was thought to be a reflection of the excited‐state proton‐transfer reaction in the system, is explained by considering the difference in the influence of H2O and D2O on the nonradiative rates and ground‐state exchange of the proton with the solvent.
Reversible Chemical Reactions for Single‐Color Multiplexing Microscopy
Authors: Brox Dominik , Schwering Michael , Engelhardt Johann , Herten Dirk‐Peter
Published: April 2014

Recent developments in biology demand an increasing number of simultaneously imaged structures with standard fluorescence microscopy. However, the number of multiplexed channels is limited for most multiplexing modalities, such as spectral multiplexing or fluorescence‐lifetime imaging. We propose extending the number of imaging channels by using chemical reactions, controlling the emissive state of fluorescent dyes. As proof of concept, we reversibly switch a fluorescent copper sensor to enable successive imaging of two different structures in the same spectral channel. We also show that this chemical multiplexing is orthogonal to existing methods. By using two different dyes, we combine chemical with spectral multiplexing for the simultaneous imaging of four different structures with only two spectrally different channels. We characterize and discuss the approach and provide perspectives for extending imaging modalities in stimulated emission depletion microscopy, for which spectral multiplexing is technically demanding.
Adolescent MDMA exposure diminishes the physiological and neurotoxic consequences of an MDMA binge in female rats
Authors: Piper Brian J. , Henderson Christina S. , Meyer Jerrold S.
Published: April 2014

Intermittent MDMA pretreatment blocked the reductions in serotonin transporter (SERT) binding induced by an MDMA binge in a prior study in adolescent male rats. The objective of this investigation was to determine if the physiological, behavioral, and neurochemical responses to MDMA are sexually dimorphic. Female Sprague–Dawley rats received MDMA (10 mg/kg × 2) or Saline on every fifth day from postnatal day (PD) 35–60 and an MDMA binge (5 mg/kg × 4) on PD 67. The MDMA binge induced a pronounced temperature dysregulation in MDMA‐naïve, but not MDMA‐pretreated, groups. Similarly, MDMA‐pretreated animals were resistant to the binge‐induced SERT reductions, especially in the hippocampus. Motor activity at PD 68 was not reduced by the binge, unlike the responses found in males. These results show that female rats differ from males in their responses to an MDMA binge but are similar with respect to preconditioning from prior MDMA exposure. © 2013 Wiley Periodicals, Inc. Dev Psychobiol 56: 924–934, 2014.
Cooking losses, lipid oxidation and formation of volatile compounds in foal meat as affected by cooking procedure
Authors: Lorenzo José M. , Domínguez Rubén
Published: April 2014

The present study deals with the effect of four different cooking techniques (roasting, grilling, microwave baking and frying with olive oil) on cooking losses, lipid oxidation (by thiobarbituric acid reactive substances (TBARS) measurement) and formation of volatile compounds (using solid‐phase microextraction (SPME) and gas chromatography combined with mass spectrometry (GC–MS)) of foal meat. Statistical analysis displayed significant (P < 0.001) differences on cooking losses by thermal treatment, being lower in foal steaks cooked by grilling (21.1%) and higher in those cooked by microwaving (35.2%). As expected, all the cooking methods increased the TBARS index, because high temperatures during cooking seem to cause an increase of the lipid oxidation in foal steaks, being higher in roasted and microwaved foal meat, followed by grilled and fried cooking. Thermal treatments led to an increase in total volatile compounds (ranging from 734.6 to 955.1 area units (AU) × 106/g dry matter) compared with raw steaks (301.3 AU × 106/g dry matter). As cooking temperature increased, an increase in the formation of volatile compounds and lipid oxidation was observed. The major volatile compounds were aldehydes in cooked samples, whereas in raw steaks they were esters. This indicates that the compounds produced by lipid oxidation have a great influence on the flavour of the cooked meat. Copyright © 2014 John Wiley & Sons, Ltd.
Transcranial electrical stimulation modifies the neuronal response to psychosocial stress exposure
Authors: Antal Andrea , Fischer Thomas , Saiote Catarina , Miller Robert , Chaieb Leila , Wang Danny J.J. , Plessow Franziska , Paulus Walter , Kirschbaum Clemens
Published: April 2014

Stress is a constant characteristic of everyday life in our society, playing a role in triggering several chronic disorders. Therefore, there is an ongoing need to develop new methods in order to manage stress reactions. The regulatory function of right medial‐prefrontal cortex (mPFC) is frequently reported by imaging studies during psychosocial stress situations. Here, we examined the effects of inhibitory and excitatory preconditioning stimulation via cathodal and anodal transcranial direct current stimulation (tDCS) on psychosocial stress related behavioral indicators and physiological factors, including the cortisol level in the saliva and changes in brain perfusion. Twenty minutes real or sham tDCS was applied over the right mPFC of healthy subjects before the performance of the Trier Social Stress Test (TSST). Regional cerebral blood flow (rCBF) was measured during stimulation and after TSST, using pseudo‐continuous arterial spin labeling (pCASL). Comparing the effect of the different stimulation conditions, during anodal stimulation we found higher rCBF in the right mPFC, compared to the sham and in the right amygdala, superior PFC compared to the cathodal condition. Salivary cortisol levels showed a decrease in the anodal and increase in cathodal groups after completion of the TSST. The behavioral stress indicators indicated the increase of stress level, however, did not show any significant differences among groups. In this study we provide the first insights into the neuronal mechanisms mediating psychosocial stress responses by prefrontal tDCS. Hum Brain Mapp 35:3750–3759, 2014. © 2013 Wiley Periodicals, Inc.
Informal Care and Caregiver's Health
Authors: Do Young Kyung , Norton Edward C. , Stearns Sally C. , Van Houtven Courtney Harold
Published: April 2014

This study aims to measure the causal effect of informal caregiving on the health and health care use of women who are caregivers, using instrumental variables. We use data from South Korea, where daughters and daughters‐in‐law are the prevalent source of caregivers for frail elderly parents and parents‐in‐law. A key insight of our instrumental variable approach is that having a parent‐in‐law with functional limitations increases the probability of providing informal care to that parent‐in‐law, but a parent‐in‐law's functional limitation does not directly affect the daughter‐in‐law's health. We compare results for the daughter‐in‐law and daughter samples to check the assumption of the excludability of the instruments for the daughter sample. Our results show that providing informal care has significant adverse effects along multiple dimensions of health for daughter‐in‐law and daughter caregivers in South Korea. Copyright © 2013 John Wiley & Sons, Ltd.
The hippocampus, medial prefrontal cortex, and selective memory retrieval: Evidence from a rodent model of the retrieval‐induced forgetting effect
Authors: Wu Jade Q. , Peters Greg J. , Rittner Pedro , Cleland Thomas A. , Smith David M.
Published: April 2014

Inhibition is an important component of many cognitive functions, including memory. For example, the retrieval‐induced forgetting (RIF) effect occurs when extra practice with some items from a study list inhibits the retrieval of the nonpracticed items relative to a baseline condition that does not involve extra practice. Although counterintuitive, the RIF phenomenon may be important for resolving interference by inhibiting potentially competing retrieval targets. Neuroimaging studies suggest that the hippocampus and prefrontal cortex are involved in the RIF effect, but controlled lesion studies have not yet been performed. We developed a rodent model of the RIF training procedure and trained control rats and rats with temporary inactivation of the hippocampus or medial prefrontal cortex (mPFC). Rats were trained on a list of odor cues, presented in cups of digging medium with a buried reward, followed by additional practice trials with a subset of the cues. We then tested the rats' memories for the cues and their association with reward by presenting them with unbaited cups containing the test odorants and measuring how long they persisted in digging. Control rats exhibited a robust RIF effect in which memory for the nonpracticed odors was significantly inhibited. Thus, extra practice with some odor cues inhibited memory for the others, relative to a baseline condition that involved an identical amount of training. Inactivation of either the hippocampus or the mPFC blocked the RIF effect. We also constructed a computational model of a representational learning circuit to simulate the RIF effect. We show in this model that “sideband suppression” of similar memory representations can reproduce the RIF effect and that alteration of the suppression parameters and learning rate can reproduce the lesion effects seen in our rats. Our results suggest that the RIF effect is widespread and that inhibitory processes are an important feature of memory function. © 2014 Wiley Periodicals, Inc.
Reproducibility of thoracic and abdominal aortic wall measurements with three‐dimensional, variable flip angle (SPACE) MRI
Authors: Mihai Georgeta , Varghese Juliet , Lu Bo , Zhu Hong , Simonetti Orlando P. , Rajagopalan Sanjay
Published: April 2014

Purpose

To evaluate the reproducibility and repeatability of high‐resolution, isotropic thoracic and abdominal aortic wall measurements, and determine the implications they have on the number of subjects necessary for future clinical trials.

Materials and Methods

Using a T1‐weighted three‐dimensional MRI SPACE sequence, we evaluated the interobserver, intraobserver, and scan–rescan variability of isotropic thoracic and abdominal aortic wall measurements in 15 cardiovascular diseased patients and 6 normal volunteers. Main outcome analyses were intracorrelation coefficient (ICC), mean relative error (mRE), and sample size calculation at 80% power to be used to compare placebo group and treatment group means in future two‐arm randomized clinical trials.

Results

Excellent reliability, ICC > 0.8 (P < 0.001) and small mRE < 10% were demonstrated for the interobserver, intraobserver, and scan–rescan variability for all investigated measures: lumen area (LA), outer wall area (OWA), wall area (VWA), total wall volume (TWV), and percentage wall volume (%WV). Sample size calculation revealed slightly different sample size per treatment arm for thoracic and abdominal aorta segments (maximum number of subjects: 352 subjects for thoracic segment versus 421 subjects for abdominal segment for LA at 5% difference, and minimum of 3 thoracic versus 4 abdominal subjects needed for %WV evaluation at 25% difference).

Conclusion

Our study demonstrates the reproducibility and repeatability of SPACE aortic plaque measurements, and gives insight into the number of subjects needed for the design of therapeutic studies in aortic atherosclerosis. J. Magn. Reson. Imaging 2015;41:202–212. © 2013 Wiley Periodicals, Inc.