bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly Efficient Solid‐Phase Labeling of Saccharides within Boronic Acid Functionalized Mesoporous Silica Nanoparticles
Authors: Pan Xianghua , Chen Yang , Zhao Peixuan , Li Daojin , Liu Zhen
Published: April 2015

Labeling is critical for the detection, quantitation, and structural identification of saccharides. However, conventional liquid‐phase labeling suffers from apparent disadvantages, such as time‐consuming, the presence of excessive labeling reagent, and high applicable saccharide concentration. A solid‐phase approach is presented for highly efficient labeling of saccharides, using boronic acid functionalized mesoporous silica nanoparticles (MSNs) as a selective extraction sorbent and nanoscale reactor. The solid‐phase labeling approach exhibited several significant advantages, including: much faster reaction speed (taking only 2 min), high product purity, and much lower applicable saccharide concentration (four orders of magnitude lower than that of liquid‐phase labeling). Thus, this labeling approach opens up new avenues to the facile and efficient labeling of saccharides.
Amphiphilic Tobramycins with Immunomodulatory Properties
Authors: Guchhait Goutam , Altieri Anthony , Gorityala Balakishan , Yang Xuan , Findlay Brandon , Zhanel George G. , Mookherjee Neeloffer , Schweizer Frank
Published: April 2015

Amphiphilic aminoglycosides (AAGs) are an emerging source of antibacterials to combat infections caused by antibiotic‐resistant bacteria. Mode‐of‐action studies indicate that AAGs predominately target bacterial membranes, thereby leading to depolarization and increased permeability. To assess whether AAGs also induce host‐directed immunomodulatory responses, we determined the AAG‐dependent induction of cytokines in macrophages in the absence or presence of lipopolysaccharide (LPS). Our results show for the first time that AAGs can boost the innate immune response, specifically the recruitment of immune cells such as neutrophils required for the resolution of infections. Moreover, AAGs can selectively control inflammatory responses induced in the presence of endotoxins to prevent septic shock. In conclusion, our study demonstrates that AAGs possess multifunctional properties that combine direct antibacterial activity with host‐directed clearance effects reminiscent of those of host‐defense peptides.
The Ruthenostannylene Complex [Cp*(IXy)H2Ru‐Sn‐Trip]: Providing Access to Unusual Ru‐Sn Bonded Stanna‐imine, Stannene, and Ketenylstannyl Complexes
Authors: Liu Hsueh‐Ju , Ziegler Micah S. , Tilley T. Don
Published: April 2015

Reactivity studies of the thermally stable ruthenostannylene complex [Cp*(IXy)(H)2RuSnTrip] (1; IXy=1,3‐bis(2,6‐dimethylphenyl)imidazol‐2‐ylidene; Cp*=η5‐C5Me5; Trip=2,4,6‐iPr3C6H2) with a variety of organic substrates are described. Complex 1 reacts with benzoin and an α,β‐unsaturated ketone to undergo [1+4] cycloaddition reactions and afford [Cp*(IXy)(H)2RuSn(κ2‐O,O‐OCPhCPhO)Trip] (2) and [Cp*(IXy)(H)2RuSn(κ2‐O,C‐OCPhCHCHPh)Trip] (3), respectively. The reaction of 1 with ethyl diazoacetate resulted in a tin‐substituted ketene complex [Cp*(IXy)(H)2RuSn(OC2H5)(CHCO)Trip] (4), which is most likely a decomposition product from the putative ruthenium‐substituted stannene complex. The isolation of a ruthenium‐substituted stannene [Cp*(IXy)(H)2RuSn(Flu)Trip] (5) and stanna‐imine [Cp*(IXy)(H)2RuSn(κ2‐N,O‐NSO2C6H4Me)Trip] (6) complexes was achieved by treatment of 1 with 9‐diazofluorene and tosyl azide, respectively.
Umpolung of Methylenephosphonium Ions in Their Manganese Half‐Sandwich Complexes and Application to the Synthesis of Chiral Phosphorus‐Containing Ligand Scaffolds
Authors: Valyaev Dmitry A. , Filippov Oleg A. , Lugan Noël , Lavigne Guy , Ustynyuk Nikolai A.
Published: April 2015

Half‐sandwich manganese methylenephosphonium complexes [Cp(CO)2Mn(η2‐R2PC(H)Ph)]BF4 were obtained in high yield through a straightforward reaction sequence involving a classical Fischer‐type manganese complex and a secondary phosphine as key starting materials. The addition of various nucleophiles (Nu) to these species took place regioselectively at the double‐bonded carbon center of the coordinated methylenephosphonium ligand R2P+C(H)Ph to produce the corresponding chiral phosphine complexes [Cp(CO)2Mn(κ1‐R2PC(H)(Ph)Nu)], from which the phosphines were ultimately recovered as free entities upon simple irradiation with visible light. The synthetic potential of this umpolung approach is illustrated herein by the preparation of novel chiral pincer‐type phosphine–NHC–phosphine ligand architectures.
Organocatalytic Asymmetric Addition of Naphthols and Electron‐Rich Phenols to Isatin‐Derived Ketimines: Highly Enantioselective Construction of Tetrasubstituted Stereocenters
Authors: Montesinos‐Magraner Marc , Vila Carlos , Cantón Rubén , Blay Gonzalo , Fernández Isabel , Muñoz M. Carmen , Pedro José R.
Published: April 2015

A quinine‐derived thiourea organocatalyst promoted the highly enantioselective addition of naphthols and activated phenols to ketimines derived from isatins. The reaction afforded chiral 3‐amino‐2‐oxindoles with a quaternary stereocenter in high yields (up to 99 %) with excellent enantioselectivity (up to 99 % ee). To the best of our knowledge, this transformation is the first highly enantioselective addition of naphthols to ketimines.
Experimental investigation of steam‐CO2‐foam flooding: combination of CO2‐foam flooding and steam injection as an effective enhanced oil recovery (EOR) method in heavy oil reservoirs
Authors: Nejatian Daraei H. , Khodapanah E. , Sahraei E.
Published: April 2015

The effects of steam‐CO2‐foam flooding on the recovery of medium–heavy crude oil have been studied using sand pack models under reservoir conditions of 1550 psi and 131 °F. In order to investigate the enhanced oil recovery (EOR) potential of steam‐CO2‐foam flooding, three different types of oil recovery experiments including CO2‐foam flooding, CO2‐foam flooding after water flooding, and steam‐CO2‐foam flooding have been conducted. Experiments for the first two cases were conducted using 1.3 PV injection of CO2‐foam. In the other case, 0.3 PV of steam injection was followed by 1 PV of CO2‐foam flooding. The ultimate oil recovery values obtained using the first two scenarios have been 57.5 and 41.21, respectively, indicating that applying CO2‐foam flooding as a tertiary EOR method after water flooding is not favorable. The ultimate oil recovery obtained during the third scenario has been 75.64%, which clearly shows that steam‐CO2‐foam flooding improves oil recovery with lower pore volume of the injected CO2‐foam. The effect of high surfactant concentration slug injection on the steam‐CO2‐foam flooding performance has also been investigated. The ultimate oil recovery obtained using slug with a high concentration of surfactant solution (0.75 wt%) and CO2has been 83.88% which shows that slug increases foam stability and improves CO2‐foam sweep efficiency. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.
A COMPREHENSIVE STUDY ON APOPTOSIS INDUCTION BY AZADIRACHTIN IN Spodoptera frugiperda CULTURED CELL LINE Sf9
Authors: Shu Benshui , Wang Wenxiang , Hu Qingbo , Huang Jingfei , Hu Meiying , Zhong Guohua
Published: April 2015

The induction of apoptosis by azadirachtin, a well‐known botanical tetranortriterpenoid isolated from the neem tree (Azadirachta indica A. Juss) and other members of the Meliaceae, was investigated in Spodoptera frugiperda cultured cell line (Sf9). Morphological changes in Sf9 cells treated by various concentrations of azadirachtin were observed at different times under light microscopy. Morphological and biochemical analysis indicated that Sf9 cells treated by 1.5 μg/mL azadirachtin showed typical morphological changes, which were indicative of apoptosis and a clear DNA ladder. The flow cytometry analysis showed the apoptosis rate reached a maximum value of 32.66% at 24 h with 1.5 μg/mL azadirachtin in Sf9 cells. The inhibition of Sf9 cell proliferation suggested that the effect of azadirachtin was dose dependent and the EC50 at 48 and 72 h was 2.727 × 10−6 and 6.348 × 10−9 μg/mL, respectively. The treatment of azadirachtin in Sf9 cells could significantly increase the activity of Sf caspase‐1, but showed no effect on the activity of Topo I, suggesting that the apoptosis induced by azadirachtinin Sf9 cells is through caspase‐dependent pathway. These results provided not only a series of morphological, biochemical, and toxicological comprehensive evidences for induction of apoptosis by azadirachtin, but also a reference model for screening insect cell apoptosis inducers from natural compounds.
Testing theories of preferential attachment in random networks of citations
Authors: Smolinsky Lawrence , Lercher Aaron , McDaniel Andrew
Published: April 2015

In this article we examine 2 classic stochastic models of the accumulation of citations introduced by H.A. Simon and Derek John de Solla Price. These models each have 2 distinct aspects: growth, which is the introduction of new articles, and preferential attachment, which describes how established articles accumulate new citations. The attachment rules are the subtle portion of these models that supply the interesting explanatory power. Previous treatments included both aspects. Here we separate preferential attachment from the growth aspect of the model. This separation allows us to examine the results of the preferential attachment rules without confounding these with growth in the number of articles available to receive citations. We introduce the method using Markov chains. We show how to overcome the mathematical and computational complexity to obtain results. A comparison of Simon's and Price's rules are computed in 3 Journal Citation Reports subject categories using articles published in the 1960s and allowed to accumulate citations to 1980. This comparison cannot be made through analysis of power laws.
BRICS countries and scientific excellence: A bibliometric analysis of most frequently cited papers
Authors: Bornmann Lutz , Wagner Caroline , Leydesdorff Loet
Published: April 2015

The BRICS countries (Brazil, Russia, India, China, and South Africa) are notable for their increasing participation in science and technology. The governments of these countries have been boosting their investments in research and development to become part of the group of nations doing research at a world‐class level. This study investigates the development of the BRICS countries in the domain of top‐cited papers (top 10% and 1% most frequently cited papers) between 1990 and 2010. To assess the extent to which these countries have become important players at the top level, we compare the BRICS countries with the top‐performing countries worldwide. As the analyses of the (annual) growth rates show, with the exception of Russia, the BRICS countries have increased their output in terms of most frequently cited papers at a higher rate than the top‐cited countries worldwide. By way of additional analysis, we generate coauthorship networks among authors of highly cited papers for 4 time points to view changes in BRICS participation (1995, 2000, 2005, and 2010). Here, the results show that all BRICS countries succeeded in becoming part of this network, whereby the Chinese collaboration activities focus on the US.
Experimentelle Untersuchungen zu Glas‐Polycarbonat‐Verbundtafeln
Authors: Weimar Thorsten
Published: April 2015

Die Anforderungen an Verglasungen in Fassadenkonstruktionen nehmen durch die Erfüllung zahlreicher neuer Aufgaben stetig zu. Das Basismaterial Glas kann diese Anforderungen häufig nur in Kombination mit anderen Materialien erfüllen. Im Bereich der Sicherheitsgläser werden deshalb Glas‐Polycarbonat‐Verbundtafeln eingesetzt. Glas besitzt eine hohe Materialsteifigkeit und Polycarbonat zeichnet sich durch eine hohe Schlagzähigkeit bei niedrigem Gewicht aus. Die Verbundtafeln bieten im Vergleich zu konventionellen Verbundsicherheitsgläsern eine hohe Widerstandsfähigkeit gegen äußere Einwirkungen bei schlankeren Querschnitten und niedrigem Eigengewicht. Dadurch können auch die Rahmen‐ und Auflagerkonstruktionen schlanker ausfallen. Der nachträgliche Einbau in Bestandsgebäude und die Weiterverarbeitung zu Mehrscheiben‐Isolierglas gestalten sich einfacher. Eine Verwendung als Horizontalverglasung ist in Deutschland allerdings nur möglich, wenn die Anforderungen an Verbundsicherheitsglas erfüllt werden. Neben dem Tragverhalten ist hierzu auch die Resttragfähigkeit von besonderer Bedeutung. Die Bemessung der Glas‐Polycarbonat‐Verbundtafeln erfordert zudem die genaue Kenntnis der Materialeigenschaften und deren Zusammenwirken im Mehrschichtensystem. Die erforderlichen Kennwerte werden in zahlreichen experimentellen Untersuchungen bestimmt und bilden die Grundlage für ein geeignetes Bemessungsverfahren der Verbundtafeln.

Experimental research on glass‐polycarbonate composite panels

The requirements for glazing in façade constructions increase steadily in consequence of numerous new functions. The base material glass can often meet these requirements only in combination with other materials. Therefore, in the field of safety glass, glass‐polycarbonate composite panels are used. Glass possesses a high material stiffness whereas polycarbonate provides high impact strength in combination with low weight. The composite panels combine high resistance against attack with slender cross‐sections and reduced dead load in comparison to common laminated safety glass. Due to this fact, the composite enables the use of more slender frame and support structures. The supplementary installation in existing buildings and the subsequent processing to insulation glass is simple. In Germany, horizontal glazing demands laminated safety glass to meet the legal and structural requirements. In addition to the structural behaviour of the glazing, the post‐breakage performance is also assessed. Furthermore, the structural design of glass‐polycarbonate composite panels requires a profound knowledge of the material properties and the interaction of multiple layers in the composite construction. The parameters required are determined in a large number of experimental research and form the basis for a suitable design concept of composite panels.
Utility of eosin Y as a complexing reagent for the determination of citalopram hydrobromide in commercial dosage forms by fluorescence spectrophotometry
Authors: Azmi Syed Najmul Hejaz , Al‐Fazari Ahlam , Al‐Badaei Munira , Al‐Mahrazi Ruqiya
Published: April 2015

An accurate, selective and sensitive spectrofluorimetric method was developed for the determination of citalopram hydrobromide in commercial dosage forms. The method was based on the formation of a fluorescent ion‐pair complex between citalopram hydrobromide and eosin Y in the presence of a disodium hydrogen phosphate/citric acid buffer solution of pH 3.4 that was extractable in dichloromethane. The extracted complex showed fluorescence intensity at λem = 554 nm after excitation at 259 nm. The calibration curve was linear over at concentrations of 2.0–26.0 µg/mL. Under optimized experimental conditions, the proposed method was validated as per ICH guidelines. The effect of common excipients used as additives was tested and the tolerance limit calculated. The limit of detection for the proposed method was 0.121 μg/mL. The proposed method was successfully applied to the determination of citalopram hydrobromide in commercial dosage forms. The results were compared with the reference RP‐HPLC method. Copyright © 2015 John Wiley & Sons, Ltd.
Synthesis, characterization and luminescent properties of europium complexes with 2,4,6‐tris‐(2‐pyridyl)‐s‐triazine as highly efficient sensitizers
Authors: Kang Jie , Chen Ying‐Nan , Wang Ai‐Ling , Li Hai‐Yan , Qu Yan‐Rong , Zhang Hai‐Xia , Chu Hai‐Bin , Zhao Yong‐Liang
Published: April 2015

Using 2,4,6‐tris‐(2‐pyridyl)‐s‐triazine (TPTZ) as a neutral ligand, and p‐hydroxybenzoic acid, terephthalic acid and nitrate as anion ligands, five novel europium complexes have been synthesized. These complexes were characterized using elemental analysis, rare earth coordination titrations, UV/vis absorption spectroscopy and infrared spectroscopy. Luminescence spectra, luminescence lifetime and quantum efficiency were investigated and the mechanism discussed in depth. The results show that the complexes have excellent emission intensities, long emission lifetimes and high quantum efficiencies. The superior luminescent properties of the complexes may be because the triplet energy level of the ligands matches well with the lowest excitation state energy level of Eu3+. Moreover, changing the ratio of the ligands and metal ions leads to different luminescent properties. Among the complexes, Eu2(TPTZ)2(C8H4O4)(NO3)4(C2H5OH)·H2O shows the strongest luminescence intensity, longest emission lifetime and highest quantum efficiency. Copyright © 2015 John Wiley & Sons, Ltd.
Invasive Krebse in Europa
Authors: Vaeßen Susanne , Hollert Henner
Published: April 2015

Nicht heimische Krebsarten gefährden europaweit heimische Krebse, wobei dem Nordamerikanischen Signalkrebs (Pacifastacus leniusculus) durch seine Temperaturtoleranz und seine hohen Vermehrungsraten eine Schlüsselrolle zukommt. Eine dreijährige Untersuchung soll die ökologischen Auswirkungen steigender Signalkrebsdichten sowie deren verhaltensbiologischen Einfluss auf Fische dokumentieren. Es zeigte sich, dass hohe Signalkrebsdichten zu starken Einbrüchen im Makrozoobenthosvorkommen führen, was wiederum geringere Fischbestände zur Folge hat. Gleichzeitig verdrängten die Krebse Bachforellen langfristig aus Höhlen, was diese im Freiland einem höheren Jagddruck aussetzt.
Primacy of surgery for colorectal cancer
Authors: Liang J , Fazio V , Lavery I , Remzi F , Hull T , Strong S , Church J
Published: April 2015

Background

The optimal technique for curative resection of colonic cancer includes high ligation of the mesenteric vessels, wide excision of the colonic mesentery and prevention of tumour cell spillage. This article reports results from the authors' institution for patients in whom complete mesocolic excision was performed long before the term was coined.

Methods

Patients operated on for cure for primary adenocarcinoma of the colon between January 1994 and December 2004 were identified from a prospectively maintained, institutional review board-approved, colorectal cancer registry. Medical records and operation notes were reviewed. The primary outcomes were recurrence (local and distal) and age-adjusted 5-year survival.

Results

Some 1013 patients (560 men and 453 women) were identified, with a median age of 69 (range 21–96) years. The most common location of the cancer was the sigmoid colon (32·9 per cent), followed by the caecum (26·7 per cent) and ascending colon (17·0 per cent). Operations were performed laparoscopically in 134 patients (13·2 per cent). Median duration of hospital stay was 7 (range 1–64, mean 8·2) days. Overall morbidity and mortality rates were 13·5 and 2·2 per cent respectively; there were 20 anastomotic leaks (2·0 per cent). Some 282 patients (27·8 per cent) had stage I, 386 (38·1 per cent) stage II and 345 (34·1 per cent) stage III disease. Median lymph node yield was 28·3 (range 0–241, mean 28·3), and 12 or more nodes were examined in 88·1 per cent of patients. Adjuvant chemotherapy was administered to 277 patients (80·3 per cent) with stage III disease. Overall local and distant recurrence rates at 5 years were 5·1 and 17·1 per cent respectively. The 5-year local recurrence rate was 2·2, 5·3 and 7·7 per cent for American Joint Committee on Cancer stages I, II and III respectively. Corresponding distant recurrence rates were 4·0, 14·7 and 30·5 per cent. The 5-year overall cancer-free age-standardized survival rate was 85·3 per cent. Five-year age standardized survival rates for patients with disease stages I, II and III were 97·7, 90·8 and 69·8 per cent respectively.

Conclusion

These data define modern results of surgery for colonic cancer with conservative use of chemotherapy.
Offense Characteristics of Incompetent to Stand Trial Defendants Charged With Violent Offenses
Authors: Schreiber Jeremy , Green Debbie , Kunz Michal , Belfi Brian , Pequeno Gabriela
Published: April 2015

The current study compared offender and offense characteristics of pretrial defendants found incompetent to stand trial (IST) against those described as general offenders by victims in the 2008 Bureau of Justice Statistics (BJS) survey and evaluated factors that differentiated IST defendants who allegedly used weapons from those who did not during the course of a violent offense. IST defendants were older and used “weapons” more frequently than those reported in the BJS survey; however, other characteristics, including use of firearms, did not differ. No demographic, clinical, or legal factors differentiated pretrial defendants who used weapons from those who did not. Overall, pretrial defendants were frequently diagnosed with a comorbid substance use disorder, and were homeless, unemployed, and had an extensive history of psychiatric hospitalizations and prior arrests at the time of their alleged offenses. Such results indicate that models for comprehensive discharge planning may have utility in addressing the unique needs of this subgroup of mentally disordered offenders. The findings also raise questions about the federal and state prohibition of gun rights to all IST defendants. Copyright © 2015 John Wiley & Sons, Ltd.
Effectiveness of various methods of formaldehyde neutralization using monoethanolamine
Authors: Coskey Andrew , Gest Thomas R.
Published: April 2015

Formaldehyde is the most commonly used fixative chemical for the preservation of human cadavers used for educational purposes in the United States. Formaldehyde is also a known carcinogenic agent whose exposure level is regulated by guidelines of the Occupational Safety and Health Administration. Various methods for formaldehyde neutralization exist, yet many donations programs do not take any steps to neutralize the formaldehyde in embalmed donor bodies. The effectiveness of monoethanolamine (MEA) in neutralizing formaldehyde is well documented when used as a final injection during embalming. The purpose of this study is to report the effectiveness of several post‐embalming techniques of formaldehyde neutralization. Twenty‐four donor bodies were assigned to four experimental groups of six. For the three experimental groups, the techniques tested involve delivery of a 20:1 dilution of deionized water:MEA via recannulization and gravity flow infusion, compartment injection, and alternate wetting solution containing four percent MEA. Our results indicated that spray bottle delivery was not effective in neutralization of formaldehyde compared to the control group, but that formaldehyde levels decreased when recannulization or compartment injection were used. The most effective method of formaldehyde neutralization was compartment injection of MEA solution (P < 0.01). The results of this study indicate that, in situations where MEA is not used as a final infusion during embalming, compartment injection of MEA solution is an effective method of formaldehyde neutralization. Clin. Anat. 28:449–454, 2015. © 2015 Wiley Periodicals, Inc.
Design of experiment (DOE) for microstrip transmission line in RF and microwave undergraduate course
Authors: Aftanasar Md Shahar , Zalina Abdul Aziz , Ngah Umi Kalthum
Published: April 2015

This paper describes the implementation of Design of Experiment (DOE) for RF and Microwave course. The objective is to demonstrate the use DOE in investigative laboratory activity for 3rd year students in RF and Microwave Course. Detailed explanation on the proposed framework, student activity, formulation, and learning process were outlined in an open‐ended cooperative laboratory activity. The scenario requires students to determine which Microstrip Transmission Line parameter significantly affects the performance of the transmission line due to a ± 5% physical variation in the parameter from its nominal value. The outcome from the study outlined the basic procedure to apply DOE as a learning process for determining factors influencing the output functional performance. © 2015 Wiley Periodicals, Inc. Comput. Appl. Eng. Educ. Comput Appl Eng Educ 23:658–666, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21635
Optimal treatment scheduling of ionizing radiation and sunitinib improves the antitumor activity and allows dose reduction
Authors: Kleibeuker Esther A. , ten Hooven Matthijs A. , Castricum Kitty C. , Honeywell Richard , Griffioen Arjan W. , Verheul Henk M. , Slotman Ben J. , Thijssen Victor L.
Published: April 2015

The combination of radiotherapy with sunitinib is clinically hampered by rare but severe side effects and varying results with respect to clinical benefit. We studied different scheduling regimes and dose reduction in sunitinib and radiotherapy in preclinical tumor models to improve potential outcome of this combination treatment strategy. The chicken chorioallantoic membrane (CAM) was used as an angiogenesis in vivo model and as a xenograft model with human tumor cells (HT29 colorectal adenocarcinoma, OE19 esophageal adenocarcinoma). Treatment consisted of ionizing radiation (IR) and sunitinib as single therapy or in combination, using different dose‐scheduling regimes. Sunitinib potentiated the inhibitory effect of IR (4 Gy) on angiogenesis. In addition, IR (4 Gy) and sunitinib (4 days of 32.5 mg/kg per day) inhibited tumor growth. Ionizing radiation induced tumor cell apoptosis and reduced proliferation, whereas sunitinib decreased tumor angiogenesis and reduced tumor cell proliferation. When IR was applied before sunitinib, this almost completely inhibited tumor growth, whereas concurrent IR was less effective and IR after sunitinib had no additional effect on tumor growth. Moreover, optimal scheduling allowed a 50% dose reduction in sunitinib while maintaining comparable antitumor effects. This study shows that the therapeutic efficacy of combination therapy improves when proper dose‐scheduling is applied. More importantly, optimal treatment regimes permit dose reductions in the angiogenesis inhibitor, which will likely reduce the side effects of combination therapy in the clinical setting. Our study provides important leads to optimize combination treatment in the clinical setting.
Nonaqueous Synthesis of a Bismuth Vanadate Photocatalyst By Using Microwave Heating: Photooxidation versus Photosensitized Decomposition in Visible‐Light‐Driven Photocatalysis
Authors: Hofmann Max , Rainer Martin , Schulze Steffen , Hietschold Michael , Mehring Michael
Published: April 2015

A new synthetic route to monoclinic bismuth vanadate using a concept adapted from a nonaqueous synthesis strategy for nanostructured organic–inorganic hybrid materials and metal oxides, introduced recently as twin polymerization, is reported. Microwave‐assisted synthesis starting from bismuth(III) tert‐butoxide and vanadium(V) oxytri(tert‐butoxide) in the presence of 2‐methoxybenzyl alcohol, 2,4‐dimethoxybenzyl alcohol, and 2‐(2‐thienyl)iso‐propyl alcohol gave hybrid materials, which were characterized by solid‐state 13C NMR spectroscopy, CH analysis, atomic absorption spectroscopy, and energy dispersive X‐ray spectroscopy. Subsequent pyrolysis resulted in nanoscale monoclinic bismuth vanadate that showed a high photocatalytic activity. The photocatalytic decomposition of model pollutants such as rhodamine B (RhB), methyl orange, methylene blue, and orange G under visible‐light irradiation using the as‐prepared bismuth vanadate samples was studied with a focus on the influence of the agglomeration behavior. The interplay between the photooxidation of RhB, induced by the excitation of the catalyst using visible light, and the photosensitized decomposition pathway is demonstrated by degradation experiments in solution and the solid state.
CuCo2O4 Nanowires Grown on a Ni Wire for High‐Performance, Flexible Fiber Supercapacitors
Authors: Gu Shaosong , Lou Zheng , Ma Xiangdong , Shen Guozhen
Published: April 2015

Flexible/stretchable supercapacitors for energy harvesting and storage are being extensively studied to meet the demand of specific environments. We successfully fabricated a flexible fiber supercapacitor through a simple and rapid single‐step hydrothermal method, growing CuCo2O4 nanostructures on Ni wires to be used as fiber electrodes. Electrochemical investigations demonstrate that the electrode material can be used in a supercapacitor to give a remarkable performance. The high‐rate specific capacitance of the fiber‐shaped supercapacitor reached 11.09 F g−1 at a current of 2 mA and outstanding cycling stability with about 93.5 % retention at 4 mA after 4000 charge/discharge cycles. Furthermore, the flexible fiber supercapacitor does not show any apparent degradation in the bending test, illustrating its potential to be used in portable and wearable energy‐storage devices.
A Non‐Invasive NMR Method Based on Histidine Imidazoles to Analyze the pH‐Modulation of Protein–Nucleic Acid Interfaces
Authors: Cruz‐Gallardo Isabel , Del Conte Rebecca , Velázquez‐Campoy Adrián , García‐Mauriño Sofía M. , Díaz‐Moreno Irene
Published: April 2015

A useful 2J(NH) coupling‐based NMR spectroscopic approach is proposed to unveil, at the molecular level, the contribution of the imidazole groups of histidines from RNA/DNA‐binding proteins on the modulation of binding to nucleic acids by pH. Such protonation/deprotonation events have been monitored on the single His96 located at the second RNA/DNA recognition motif (RRM2) of T‐cell intracellular antigen‐1 (TIA‐1) protein. The pKa values of the His96 ionizable groups were substantially higher in the complexes with short U‐rich RNA and T‐rich DNA oligonucleotides than those of the isolated TIA‐1 RRM2. Herein, the methodology applied to determine changes in pKa of histidine side chains upon DNA/RNA binding, gives valuable information to understand the pH effect on multidomain DNA/RNA‐binding proteins that shuttle among different cellular compartments.
Photoisomerisation in Aminoazobenzene‐Substituted Ruthenium(II) Tris(bipyridine) Complexes: Influence of the Conjugation Pathway
Authors: Amar Anissa , Savel Paul , Akdas‐Kilig Huriye , Katan Claudine , Meghezzi Hacène , Boucekkine Abdou , Malval Jean‐Pierre , Fillaut Jean‐Luc
Published: April 2015

Transition‐metal complexes containing stimuli‐responsive systems are attractive for applications in optical devices, photonic memory, photosensing, as well as luminescence imaging. Amongst them, photochromic metal complexes offer the possibility of combining the specific properties of the metal centre and the optical response of the photochromic group. The synthesis, the electrochemical properties and the photophysical characterisation of a series of donor–acceptor azobenzene derivatives that possess bipyridine groups connected to a 4‐dialkylaminoazobenzene moiety through various linkers are presented. DFT and TD‐DFT calculations were performed to complement the experimental findings and contribute to their interpretation. The position and nature of the linker (ethynyl, triazolyl, none) were engineered and shown to induce different electronic coupling between donor and acceptor in ligands and complexes. This in turn led to strong modulations in terms of photoisomerisation of the ligands and complexes.
Reaction Optimization, Scalability, and Mechanistic Insight on the Catalytic Enantioselective Desymmetrization of 1,1‐Diborylalkanes via Suzuki–Miyaura Cross‐Coupling
Authors: Sun Ho‐Yan , Kubota Koji , Hall Dennis G.
Published: April 2015

A method for enantioselective desymmetrization of 1,1‐diborylalkanes through a stereoselective Pd‐catalyzed Suzuki–Miyaura cross‐coupling has been thoroughly optimized. The most effective ligand was found to be a α,α,α,α‐tetra‐aryl‐1,3‐dioxolane‐4,5‐dimethanol (TADDOL)‐derived phosphoramidite. Results show that in order to achieve high selectivity, a suitable balance between the sterics of the aryl groups and the amino group on the ligand must be achieved. While the base has been known to facilitate transmetallation in cross‐coupling reactions, mechanistic studies on this desymmetrization process reveal that the base, in the presence of KHF2, likely plays an additional role in the hydrolysis of the pinacol boronates to the corresponding boronic acids. Through an in depth optimization of the chiral ligand and mechanistic studies, it was possible to obtain ee values over 90 % for several aryl bromides and to develop a reliably scalable process (up to one gram of 1,1‐diborylalkane substrate).
Towards Solar Energy Storage in the Photochromic Dihydroazulene–Vinylheptafulvene System
Authors: Cacciarini Martina , Skov Anders B. , Jevric Martyn , Hansen Anne S. , Elm Jonas , Kjaergaard Henrik G. , Mikkelsen Kurt V. , Brøndsted Nielsen Mogens
Published: April 2015

One key challenge in the field of exploitation of solar energy is to store the energy and make it available on demand. One possibility is to use photochromic molecules that undergo light‐induced isomerization to metastable isomers. Here we present efforts to develop solar thermal energy storage systems based on the dihydroazulene (DHA)/vinylheptafulvene (VHF) photo/thermoswitch. New DHA derivatives with one electron‐withdrawing cyano group at position 1 and one or two phenyl substituents in the five‐membered ring were prepared by using different synthetic routes. In particular, a diastereoselective reductive removal of one cyano group from DHAs incorporating two cyano groups at position 1 turned out to be most effective. Quantum chemical calculations reveal that the structural modifications provide two benefits relative to DHAs with two cyano groups at position 1: 1) The DHA–VHF energy difference is increased (i.e., higher energy capacity of metastable VHF isomer); 2) the Gibbs free energy of activation is increased for the energy‐releasing VHF to DHA back‐reaction. In fact, experimentally, these new derivatives were so reluctant to undergo the back‐reaction at room temperature that they practically behaved as DHA to VHF one‐way switches. Although lifetimes of years are at first attractive, which offers the ultimate control of energy release, for a real device it must of course be possible to trigger the back‐reaction, which calls for further iterations in the future.
Gold(I)‐Catalyzed Selective Heterocyclization of Propargylic Thioureas: Mechanistic Study of Competitive Gold‐Activation Mode
Authors: Jiang Yu , Wei Yin , Tang Xiang‐Ying , Shi Min
Published: April 2015

A new selective gold(I)‐catalyzed intramolecular heterocyclization of propargylic thioureas has been developed, efficiently affording two kinds of cycloadducts in moderate to excellent yields with a broad substrate scope. Further mechanistic investigations indicate that competitive different gold activation modes feature in these cyclization processes. Kinetic experiments reveal that the gold activation mode is influenced by the ligand of the gold catalyst and the reaction conditions.
Chemical Synthesis of Phosphorylated Ubiquitin and Diubiquitin Exposes Positional Sensitivities of E1‐E2 Enzymes and Deubiquitinases
Authors: Bondalapati Somasekhar , Mansour Wissam , Nakasone Mark A. , Maity Suman Kumar , Glickman Michael H. , Brik Ashraf
Published: April 2015

Modification of ubiquitin by phosphorylation extends the signaling possibilities of this dynamic signal, as it could affect the activity of ligases and the processing of ubiquitin chains by deubiquitinases. The first chemical synthesis of phosphorylated ubiquitin and of Lys63‐linked diubiquitin at the proximal, distal or both ubiquitins is reported. This enabled the examination of how such a modification alters E1‐E2 activities of the ubiquitination machinery. It is found that E1 charging was not affected, while the assembly of phosphorylated ubiquitin chains was differentially inhibited with E2 enzymes tested. Moreover, this study shows that phosphorylation interferes with the recognition of linkage specific antibodies and the activities of several deubiquitinases. Notably, phosphorylation in the proximal or distal ubiquitin unit has differential effects on specific deubiquitinases. These results support a unique role of phosphorylation in the dynamics of the ubiquitin signal.
Scandium‐Catalyzed Asymmetric 1,6‐Addition of 3‐Substituted Oxindoles to Linear Dienyl Ketones
Authors: Wang Zhen , Kang Tengfei , Yao Qian , Ji Jie , Liu Xiaohua , Lin Lili , Feng Xiaoming
Published: April 2015

The first example of a N,N′‐dioxide–ScIII‐catalyzed 1,6‐addition of 3‐substituted oxindoles to dienyl ketones has been developed. This procedure tolerates a relatively wide range of 3‐substituted oxindoles under mild conditions, facilitating the preparation of various chiral oxindoles with quaternary stereocenters. In addition, the reliable catalyst was found to be effective in the asymmetric 1,6‐addition of both δ‐unsubstituted and δ‐methyl‐substituted dienyl ketones, achieving excellent regioselectivities and enantioselectivities (up to>99 % ee).
Acid/Base‐Mediated Uptake and Release of Halide Anions with a Preorganized Aryl‐Triazole Foldamer
Authors: Zhao Wei , Wang Ying , Shang Jie , Che Yanke , Jiang Hua
Published: April 2015

A new approach for the construction of artificial receptors capable of selectively uptake and release of halides to mimic the biological halide ions pumps is developed, in which the preorganized aryl‐triazole foldamer was designed to bear a resorcinolic group in the central strand as a switch regulator. By using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene/picric acid as the trigger, the foldamer can be switched between “w”‐shape and helical conformation. Due to the large, half‐open cavity as well as the additional electrostatic repulsion between oxyanions and guest halide, the foldamer in “w”‐shape possesses a much weaker affinity for chloride, bromide, and iodide anions than those in the helical conformation in 6:94 (v/v) [D6]DMSO/CDCl3. When the foldamer and chloride ions have the same initial concentrations of 1 mM, 70 % chloride ions in the solution could be reversibly bound or released upon switching.
Orchestrating the Biosynthesis of an Unnatural Pyrrolysine Amino Acid for Its Direct Incorporation into Proteins Inside Living Cells
Authors: Ehrlich Michael , Gattner Michael J. , Viverge Bastien , Bretzler Johanna , Eisen David , Stadlmeier Michael , Vrabel Milan , Carell Thomas
Published: April 2015

We here report the construction of an E. coli expression system able to manufacture an unnatural amino acid by artificial biosynthesis. This can be orchestrated with incorporation into protein by amber stop codon suppression inside a living cell. In our case an alkyne‐bearing pyrrolysine amino acid was biosynthesized and incorporated site‐specifically allowing orthogonal double protein labeling.
Merger of Visible Light Induced Oxidation and Enantioselective Alkylation with a Chiral Iridium Catalyst
Authors: Wang Chuanyong , Zheng Yu , Huo Haohua , Röse Philipp , Zhang Lilu , Harms Klaus , Hilt Gerhard , Meggers Eric
Published: April 2015

A single chiral octahedral iridium(III) complex is used for visible light activated asymmetric photoredox catalysis. In the presence of a conventional household lamp and under an atmosphere of air, the oxidative coupling of 2‐acyl‐1‐phenylimidazoles with N,N‐diaryl‐N‐(trimethylsilyl)methylamines provides aminoalkylated products in 61–93 % yields with high enantiomeric excess (90–98 % ee). Notably, the iridium center simultaneously serves three distinct functions: as the exclusive source of chirality, as the catalytically active Lewis acid, and as a central part of the photoredox sensitizer. This conceptionally simple reaction Scheme may provide new avenues for the green synthesis of non‐racemic chiral molecules.
ChemInform Abstract: Homoatomic Clustering in T4Ga5 (T = Ta, Nb, Ta/Mo): A Story of Reluctant Intermetallics Crystallizing in a New Binary Structure Type.
Authors: Fredrickson Rie T. , Kilduff Brandon J. , Fredrickson Daniel C.
Published: April 2015

Ta4Ga5, Nb4Ga5, and Ta3.86Mo0.14Ga5 are prepared from the elements (850—1100 °C, 198—700 h) and characterized by powder and single crystal XRD, EDS, electron probe microanalysis, and DFT electronic structure calculations.
ChemInform Abstract: Classical and Nonclassical Germanium Environments in High‐Pressure BaGe5.
Authors: Castillo Rodrigo , Carrillo‐Cabrera Wilder , Schwarz Ulrich , Grin Yuri
Published: April 2015

The high‐pressure modification of BaGe5 is obtained from a 1:5 molar mixture of Ba6Ge25 and Ba (multianvil press, 15 GPa, 1000‐1200 K, 2 h).
ChemInform Abstract: Cs8[Fe4S10] and Cs7[Fe4S8], Two New Sulfido Ferrates with Different Tetrameric Anions.
Authors: Schwarz Michael , Roehr Caroline
Published: April 2015

Cs8[Fe4S10] (I) and Cs7[Fe4S8] (II) are prepared from stoichiometric samples of Fe, S, and Cs2S2 (corundum crucible in autoclave, ≤ 1070 K, 12 h).
ChemInform Abstract: Syntheses, Structures, and Nonlinear‐Optical Properties of Metal Sulfides Ba2Ga8MS16 (M: Si, Ge).
Authors: Liu Bin‐Wen , Zeng Hui‐Yi , Zhang Ming‐Jian , Fan Yu‐Hang , Guo Guo‐Cong , Huang Jin‐Shun , Dong Zhen‐Chao
Published: April 2015

The new title compounds are synthesized by solid state reactions of Ba, Ga2S9, Ge (Si), and S in a molar ratio of 2:4:1:4 (quartz tubes, 300 °C for 5 h, 650 °C for 10 h, and 980 °C for 5 d) and characterized by single crystal XRD, IR and UV/VIS/NIR diffuse reflectance spectroscopy, second harmonic generation measurements, laser‐induced damage threshold measurements, and DFT electronic band structure calculations.
ChemInform Abstract: Crystal Structure and Ion Conductivity of a New Mixed‐Anion Phosphate LiMg3(PO4)P2O7.
Authors: Kim Sung‐Chul , Lee Mi‐Sun , Kang Jinyeong , Kim Young‐Il , Kim Seung‐Joo
Published: April 2015

LiMg3(PO4)P2O7 is prepared by solid‐state reaction of a 1:3:3 molar mixture of Li2CO3, MgO, and (NH4)2HPO4 (1.
ChemInform Abstract: Crystal Cluster Growth and Physical Properties of the EuSbSe3 and EuBiSe3 Phases.
Authors: Forbes Scott , Tseng Yu‐Chih , Mozharivskyj Yurij
Published: April 2015

Crystal clusters of EuSbSe3 and EuBiSe3 phases are prepared by solid state reactions of a 2:1:3 molar mixture of Eu, Sb2Se/Bi2Se3, and Se (C‐coated evacuated silica ampoules, complex heating schedule).
ChemInform Abstract: Hydrothermal Growth of Lanthanide Borosilicates: A Useful Approach to New Acentric Crystals Including a Derivative of Cappelenite.
Authors: Heyward Carla C. , McMillen Colin D. , Kolis Joseph W.
Published: April 2015

The series of non‐centrosymmetric crystals (VIII)—(X) is hydrothermally prepared from precursor barium borosilicate glasses (IV) and (VI) and characterized by single crystal XRD.
ChemInform Abstract: Alkali‐Metal Thiogermanates: Sodium Channels and Variations on the La3CuSiS7 Structure Type.
Authors: Choudhury Amitava , Dorhout Peter K.
Published: April 2015

NaLn3GeS7 (Ln: Ce (I), Nd (II), Sm (III), Gd (IV), Yb (V)) are prepared by solid state reaction of LnCl3 and Na2GeS3 (graphite crucible in evacuated silica tube, 825 °C, 96 h).
ChemInform Abstract: Bi73‐: The Missing Family Member, Finally Isolated and Characterized.
Authors: Perla Luis G. , Oliver Allen G. , Sevov Slavi C.
Published: April 2015

The new compound [K(crypt)]3Bi7·2Py (crypt: 1,10‐diaza‐4,7,13,16,21,24‐hexaoxabicyclo[8.8.8]hexacosane) is synthesized from a mixture of K5Bi4, crypt, and Py in the presence of Cr(CO)3(benzene) (stirring for 4 h, 40% yield).
ChemInform Abstract: Cluster Harvesting in the WBr6—P System.
Authors: Stroebele Markus , Eichele Klaus , Meyer Hans‐Juergen
Published: April 2015

The new compound W4(PBr)Br10 is obtained by reduction of WBr6 with elemental phosphorus at 450 °C for 72 h and characterized by powder XRD, and solid state MAS 31P NMR spectroscopy.
ChemInform Abstract: Structure and Bonding of Bi4Ir: A Difficult‐to‐Access Bismuth Iridide with a Unique Framework Structure.
Authors: Isaeva Anna , Ruck Michael , Schaefer Konrad , Rodewald Ute Ch. , Poettgen Rainer
Published: April 2015

Crystals of the new compound Bi4Ir are prepared by reaction of a precursor of nominal composition Sm3Ir3Sb7 (obtained by arc‐melting the elements) with liquid bismuth (corundum crucible, 1370 K, 7 d, followed by annealing at 1070 K for 7 d).
ChemInform Abstract: Rhodium‐Catalyzed Arylative Cyclization for the Enantioselective Synthesis of (Trifluoromethyl)cyclobutanols.
Authors: Johnson Thomas , Choo Ken‐Loon , Lautens Mark
Published: April 2015

Optically active cyclobutanols are obtained via cyclization of alkynones with arylboronic acids by using a chiral bicyclooctadiene ligand.
ChemInform Abstract: Hexaalkylguanidinium Salts as Ionic Liquids — Applications in Titanium and Aluminium Alcoholate Assisted Synthesis.
Authors: Arkhipova Maria , Eichel Svetlana , Maas Gerhard
Published: April 2015

Guanidinium‐based ionic liquids containing titanium or aluminum alcoholate are successfully applied as Lewis‐acidic catalytic media for some dehydrating cyclocondensation reactions: i.
ChemInform Abstract: Ring Opening of N‐Sulfonyl Aziridines by Amines in Silica‐Water.
Authors: Li Tiantian , Ma Xiaosi , Qi Junmei , Sun Feifei , Ma Ning
Published: April 2015

When primary and secondary amines are used in excess, they react with N‐sulfonyl aziridines, mainly affording 1:1 ring opening products (III), (V), (XI).
ChemInform Abstract: Diastereoselective Photodimerization Reactions of Chromone‐2‐carboxamides to Construct a C2‐Chiral Scaffold.
Authors: Yagishita Fumitoshi , Baba Nozomi , Ueda Yuki , Katabira Satoshi , Kasashima Yoshio , Mino Takashi , Sakamoto Masami
Published: April 2015

Irradiation of chromone‐carboxamides bearing a chiral auxiliary, e.g. (I), results in diastereoselective formation of a C2‐chiral anti‐HH dimer scaffold.
ChemInform Abstract: A Highly Efficient Catalyst for Selective Oxidative Scission of Olefins to Aldehydes: Abnormal‐NHC—Ru(II) Complex in Oxidation Chemistry.
Authors: Daw Prosenjit , Petakamsetty Ramu , Sarbajna Abir , Laha Siladitya , Ramapanicker Ramesh , Bera Jitendra K.
Published: April 2015

A novel annulated imidazo[1,2‐a][1,8]naphthyridine‐based NHC Ru‐complex is synthesized and successfully applied as catalyst in the oxidative cleavage of structurally diverse C=C bonds to yield aldehydes.
ChemInform Abstract: Transition Metal‐Free Intermolecular α‐C—H Amination of Ethers at Room Temperature.
Authors: Buslov Ivan , Hu Xile
Published: April 2015

The title reaction uses hypervalent iodine as oxidant via a radical pathway.
ChemInform Abstract: Iodine‐Catalyzed Three‐Component Reaction of Quinazoline‐2,5‐diones with Aldehydes and Styrenes for the Synthesis of Allylamine Derivatives.
Authors: Zhang Zhang , Zhang Yu‐Shan , Quan Zheng‐Jun , Da Yu‐Xia , Wang Xi‐Cun
Published: April 2015

The mechanism of the unexpected deacylation observed in the reactions using methylglyoxal (V) remains unclear.
ChemInform Abstract: Copper‐Catalyzed α‐Selective Allylic Alkylation of Heteroaryllithium Reagents.
Authors: Vila Carlos , Hornillos Valentin , Fananas‐Mastral Martin , Feringa Ben L.
Published: April 2015

2‐Allyl‐substituted thiophenes and furans are synthesized in a highly regioselective, ligand‐free copper‐catalyzed reaction of 2‐heteroaryllithium reagents and allyl halides.
ChemInform Abstract: Ionic Liquids as Recyclable and Separable Reaction Media in Rh‐Catalyzed Decarbonylation of Aromatic and Aliphatic Aldehydes.
Authors: Malcho Phillip , Garcia‐Suarez Eduardo J. , Riisager Anders
Published: April 2015

It is found that the catalytic performance strongly depends on the employed ionic liquid and its thermal stability.
ChemInform Abstract: Enantioselective Copper(II)‐Catalyzed Henry Reaction Utilizing Chiral Aziridinyl Alcohols.
Authors: Wang Xiaojuan , Zhao Wenxian , Li Gaowei , Wang Jin , Liu Guanjun , Liu Lantao , Zhao Ruijuan , Wang Mincan
Published: April 2015

A novel type of aziridine based ligands is synthesized and the derivative LIG is successfully applied under optimized conditions for the enantioselective Henry reaction of aromatic aldehydes (I).
ChemInform Abstract: Zinc‐Catalyzed Cyclopropenation of Alkynes via 2‐Furylcarbenoids.
Authors: Gonzalez Maria J. , Lopez Luis A. , Vicente Ruben
Published: April 2015

An unprecedented reactivity pattern of carbenoids is demonstrated for the first time for the zinc‐catalyzed cyclopropanation of alkynes.