bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell‐Penetrating, Dimeric α‐Helical Peptides: Nanomolar Inhibitors of HIV‐1 Transcription
Authors: Jang Sangmok , Hyun Soonsil , Kim Seoyeon , Lee Seonju , Lee Im‐Soon , Baba Masanori , Lee Yan , Yu Jaehoon
Published: July 2014

We constructed dimeric α‐helical peptide bundles based on leucine (L) and lysine (K) residues for both efficient cell penetration and inhibition of the Tat–TAR interaction. The LK dimers can penetrate nearly quantitatively into eukaryotic cells and effectively inhibit the elongation of the TAR transcript at low nanomolar concentrations. The effective inhibition of HIV‐1 replication strongly suggests that the LK dimer has strong potential as an anti‐HIV‐1 drug.
Synthesis of Isocoumarins through Three‐Component Couplings of Arynes, Terminal Alkynes, and Carbon Dioxide Catalyzed by an NHC–Copper Complex
Authors: Yoo Woo‐Jin , Nguyen Thanh V. Q. , Kobayashi Shū
Published: July 2014

A copper‐catalyzed multicomponent coupling reaction between in situ generated ortho‐arynes, terminal alkynes, and carbon dioxide was developed to access isocoumarins in moderate to good yields. The key to this CO2‐incorporating reaction was the use of a versatile N‐heterocyclic carbene/copper complex that was able to catalyze multiple transformations within the three‐component reaction.
An Easy Way To Prepare Monolithic Inorganic Oxide Aerogels
Authors: Ren Lili , Cui Sumin , Cao Fengchao , Guo Qinghui
Published: July 2014

Inorganic oxide aerogels have unique thermal, optical, electrical, magnetic, and chemical properties, which result in them potentially having a broad range of applications. However, their preparation is commonly based on a supercritical drying method, which greatly limits real applications of aerogels and their commercialization. Here we demonstrate a general method for drying wet gels to form aerogels that is based on the sublimation of organic solvent. The organic solvent must have a low surface tension, undergo sublimation easily, and have a high freezing point to allow the rapid synthesis of monolithic inorganic oxide aerogels under vacuum conditions. This cost‐effective process will facilitate application of aerogel materials. This approach may also be used for the preparation of other porous materials, whose theoretical and practical applications should be investigated.
Targeting Human C‐Type Lectin‐like Molecule‐1 (CLL1) with a Bispecific Antibody for Immunotherapy of Acute Myeloid Leukemia
Authors: Lu Hua , Zhou Quan , Deshmukh Vishal , Phull Hardeep , Ma Jennifer , Tardif Virginie , Naik Rahul R. , Bouvard Claire , Zhang Yong , Choi Seihyun , Lawson Brian R. , Zhu Shoutian , Kim Chan Hyuk , Schultz Peter G.
Published: July 2014

Acute myeloid leukemia (AML), which is the most common acute adult leukemia and the second most common pediatric leukemia, still has a poor prognosis. Human C‐type lectin‐like molecule‐1 (CLL1) is a recently identified myeloid lineage restricted cell surface marker, which is overexpressed in over 90 % of AML patient myeloid blasts and in leukemic stem cells. Here, we describe the synthesis of a novel bispecific antibody, αCLL1‐αCD3, using the genetically encoded unnatural amino acid, p‐acetylphenylalanine. The resulting αCLL1‐αCD3 recruits cytotoxic T cells to CLL1 positive cells, and demonstrates potent and selective cytotoxicity against several human AML cell lines and primary AML patient derived cells in vitro. Moreover, αCLL1‐αCD3 treatment completely eliminates established tumors in an U937 AML cell line xenograft model. These results validate the clinical potential of CLL1 as an AML‐specific antigen for the generation of a novel immunotherapeutic for AML.
Synthesis and characterization of transition metal complexes of hydrochloride salt of 3‐chlorobenzaldehyde hydralazine hydrazone: a new class of possible anti‐cariogenic agents
Authors: Bakale Raghavendra P. , Pathan Aishakhanam H. , Naik Ganesh N. , Machakanur Shrinath S. , Mangannavar Chandrashekhar V. , Muchchandi Iranna S. , Gudasi Kalagouda B.
Published: July 2014

A novel hydrazone, formed by the condensation of the hydrochloride salt of hydralazine with 3‐chlorobenzaldehyde, and its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized. Their structures have been elucidated on the basis of elemental analyses, conductance measurements, magnetic moments, and spectral (infrared, 1H NMR, UV–visible, electrospray ionization (ESI) mass) and thermal studies. The bidentate behaviour of the ligand is proposed on the basis of spectral studies. Interestingly, all four complexes exhibit different geometry around the metal centre. The conductance data of the complexes suggest them to be non‐electrolytes. The ESI mass spectra of the complexes support their monomeric nature. The compounds were tested against two Gram‐positive and three Gram‐negative bacterial strains and three fungal strains. Excellent inhibitory activity is observed against the Gram‐positive bacteria Streptococcus mutans and Enterococcus faecalis which play major roles in tooth decay. Among the fungal strains used, Candida albicans is inhibited predominantly. Copyright © 2014 John Wiley & Sons, Ltd.
Influence of fiber surface treatment on mechanical performance of Xanthoceras sorbifolia bunge husk fibers/PP composites
Authors: Yao Xu‐Dan , Liu Dong‐Yan , Sui Guo‐Xin
Published: July 2014

The PP Composites containing Xanthoceras sorbifolia Bunge husks fibers with different surface treatments were prepared. The mechanical properties such as tensile properties and impact properties of the composites were investigated. It is revealed that the composites with fibers treated by alkali and the following treatments of silane coupling agents KH570, titanate coupling agent JN‐9A, acetic anhydride, MAPP, or bleach, all performed higher in tensile properties than that with untreated fibers, while lower in impact properties. Meanwhile, all treated fibers performed better thermal stability than untreated fibers. The fibers treated by alkali followed by KH570 treatment were added into PP with different contents. It is found that as the fiber content increases, the elastic modulus and impact strength of the composites increase sharply at first followed by a decrease, while the tensile strength decrease initially and increase with a peak at 10%, then decrease continuously. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41217.
ANALYSIS OF THE Vitellogenin GENE OF RICE MOTH, Corcyra cephalonica STAINTON
Authors: Veerana Mayura , Kubera Anchanee , Ngernsiri Lertluk
Published: July 2014

Vitellogenin (Vg) is a precursor of the major yolk protein, an essential nutrient for the embryonic development of oviparous animals including insects. Here, the gene(CceVg [Corcyra cephalonica Vg] ) encoding the Vg (CceVg of moth, C. cephalonica, was cloned and sequenced. The gene sequence was 6,721‐bp long and contained 5five introns and six exons that together formed a 5,382‐bp open reading frame. The deduced protein (CceVg) consisted of 1,793 amino acid residues, including a 16‐amino‐acid signal peptide. The putative molecular weight of the primary Vg protein was 202.46 kDa. The CceVg contained all conserved domains and motifs that were commonly found in most insect Vgs except the presence of a polyserine tract at the C‐terminal region, which had not been reported in other lepidopteran Vgs. The expression pattern showed thatCceVg was first transcribed at a very low level in the early larval stage but disappeared in later stage larva. In female, theCceVg mRNA was detected in early pupal stage and throughout adult stage. Interestingly, theCceVg mRNA was detected only in mated males at low levels, not in the virgin ones. Injection ofCceVg double‐stranded RNA into early‐emergent females caused severely abnormal ovaries.
Photo‐ and pH‐Tunable Multicolor Fluorescent Nanoparticle‐Based Spiropyran‐ and BODIPY‐Conjugated Polymer with Graphene Oxide
Authors: Sharker Shazid Md. , Jeong Chan Jin , Kim Sung Min , Lee Jung‐Eun , Jeong Ji Hoon , In Insik , Lee Haeshin , Park Sung Young
Published: July 2014

We report a stimuli‐responsive fluorescent nanomaterial, based on graphene oxide coupled with a polymer conjugated with photochromic spiropyran (SP) dye and hydrophobic boron dipyrromethane (BODIPY) dye, for application in triggered target multicolor bioimaging. Graphene oxide (GO) was reduced by catechol‐conjugated polymers under mildly alkaline conditions, which enabled to formation of functionalized multicolor graphene nanoparticles that can be induced by irradiation with UV light and by changing the pH from acidic to neutral. Investigation of these nanoparticles by using AFM, fluorescence emission, and in vitro cell and in vivo imaging revealed that they show different tunable colors in bioimaging applications and, more specifically, in cancer‐cell detection. The stability, biocompatibility, and quenching efficacy of this nanocomposite open a different perspective for cell imaging in different independent colors, sequentially and simultaneously.
Through‐Space Conjugated Molecular Wire Comprising Three π‐Electron Systems
Authors: Morisaki Yasuhiro , Kawakami Naoya , Shibata Shotaro , Chujo Yoshiki
Published: July 2014

A [2.2]paracyclophane‐based through‐space conjugated oligomer comprising three π‐electron systems was designed and synthesized. The arrangement of three π‐conjugated systems in an appropriate order according to the energy band gap resulted in efficient unidirectional photoexcited energy transfer by the Förster mechanism. The energy transfer efficiency and rate constants were estimated to be >0.999 and >1012 s−1, respectively. The key point for the efficient energy transfer is the orientation of the transition dipole moments. The time‐dependent density functional theory (TD‐DFT) studies revealed the transition dipole moments of each stacked π‐electron system; each dipole moment was located on the long axis of each stacked π‐electron system. This alignment of the dipole moments is favorable for fluorescence resonance energy transfer (FRET).
Optimal Control of Midazolam Infusion for Post Operative Patients in Intensive Care Units
Authors: Padmanabhan Regina , Meskin Nader , Haddad Wassim M.
Published: July 2014

The critical task of anesthesia administration demands optimal drug titration by considering patient‐specific features and sedation requirements. Though there exist several sedation assessment monitors, physicians still largely rely on subjective sedation scoring systems. This paper presents an optimal infusion controller for the continuous infusion of midazolam along with the analgesic fentanyl. Specifically, we extend the convex optimization‐based optimal drug dosing regimen for propofol to midazolam. We additionally propose an alternative optimization approach using the Kullback‐Leibler divergence measure of two probability distributions. It is shown that by using the new proposed approach one can achieve the desired sedation level by using less drug infusion in comparison with previous methods. A nonlinear two‐compartment model is used to describe the pharmacokinetics of midazolam and a stochastic pharmacodynamic model is used that utilizes the modified Ramsay sedation scoring method to link the plasma drug concentration with the effective probabilistic sedation level.
Gain‐Scheduled H∞ Control for Tensor Product Type Polytopic Plants
Authors: Chumalee Sunan , Whidborne James F.
Published: July 2014

A tensor product (TP) model transformation is a recently proposed technique for transforming a given linear parameter‐varying (LPV) model into polytopic model form, for which there are many methods that can be used for controller design. This paper proposes an alternative approach to the design of a gain‐scheduled output feedback H∞ controller with guaranteed L2‐gain parameter‐dependent performance for a class of TP type polytopic models using parameter‐dependent Lyapunov functions where the linear matrix inequalities (LMIs) need only to be evaluated at all vertices of the system state‐space model matrices and the variation rate of the scheduled parameters. In addition, a construction technique of the intermediate controller variables is also proposed as a matrix‐valued function in the polytopic coordinates of the scheduled parameters. The performance of the proposed approach is tested on a missile autopilot design problem. Furthermore, nonlinear simulation results show the effectiveness of these proposed techniques.
Effect of Improved Tracking for Atomic Force Microscope on Piezo Nonlinear Behavior
Authors: Rana Md. Sohel , Pota Hemanshu R. , Petersen Ian R. , Habibullah Habib
Published: July 2014

Nanotechnology is an area of modern science which deals with the control of matter at dimensions of 100 nm or less. In recent years, of all the available microscopy techniques, atomic force microscopy (AFM) has proven to be extremely versatile as an investigative tool in this field. However the performance of AFM is significantly limited by the effects of hysteresis, creep, cross‐coupling, and vibration in its scanning unit, the piezoelectric tube scanner (PTS). This article presents the design and experimental implementation of a single‐input single‐output (SISO) model predictive control (MPC) scheme with a vibration compensator which is based on an identified model of the PTS. The proposed controller provides an AFM with the capability to achieve improved tracking and results in compensation of the nonlinear effects. The experimental results, which compare the tracking performances of the proposed controller for different reference signals, highlight the usefulness of the proposed control scheme.
Active Disturbance Rejection Control of a Magnetic Suspension System
Authors: Beltran‐Carbajal Francisco , Valderrabano‐Gonzalez Antonio , Favela‐Contreras Antonio R. , Rosas‐Caro Julio Cesar
Published: July 2014

This paper proposes a novel output feedback control scheme for robust stabilization and tracking tasks in a magnetic suspension system. Active disturbance rejection control, differential flatness and on‐line asymptotic disturbance estimation are properly used for the proposed control synthesis. The controlled system is subjected to a wide spectrum of unknown significant matched and unmatched disturbances due to external forces and voltages, parametric uncertainties, control and state‐dependent perturbations and possibly input unmodeled dynamics. The effectiveness and robustness of the proposed active disturbance control scheme is verified by computer simulations for the robust tracking of a rest‐to‐rest reference position trajectory specified to firstly stabilize the suspended mass at a desired vertical position and next transfer it to another equilibrium position for both continuous and switched control voltage signals.
Using a microbial physiologic and genetic approach to investigate how bacteria sense physical stimuli
Authors: Mussi María Alejandra , Actis Luis A. , de Mendoza Diego , Cybulski Larisa E.
Published: July 2014

A laboratory exercise was designed to illustrate how physical stimuli such as temperature and light are sensed and processed by bacteria to elaborate adaptive responses. In particular, we use the well‐characterized Des pathway of Bacillus subtilis to show that temperature modulates gene expression, resulting ultimately in modification of the levels of unsaturated fatty acids required to maintain proper membrane fluidity at different temperatures. In addition, we adapt recent findings concerning the modulation by light of traits related to virulence such as motility and biofilm formation in the chemotropic bacterium Acinetobacter baumannii. Beyond the theoretical background that this activity provides regarding sensing of environmental stimuli, the experimental setup includes approaches derived from classic genetics, microbiology, and biochemistry. The incorporation of these kind of teaching and training activities in middle‐advanced Microbiology or Bacterial Genetics courses promotes acquisition of general and specific techniques and improves student's comprehension of scientific literature and research. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(5):427–434, 2014.
Inhibition of epidermal growth factor signaling by the cardiac glycoside ouabain in medulloblastoma
Authors: Wolle Daniel , Lee Seung Joon , Li Zhiqin , Litan Alisa , Barwe Sonali P. , Langhans Sigrid A.
Published: July 2014

Epidermal growth factor (EGF) signaling regulates cell growth, proliferation, and differentiation. Upon receptor binding, EGF triggers cascades of downstream signaling, including the MAPK and phosphoinositide‐3‐kinase (PI3K)/Akt signaling pathways. Aberrant expression/activation of EGFR is found in multiple human cancers, including medulloblastoma, the most prevalent pediatric brain cancer, and often has been associated with metastasis, poor prognosis, and resistance to chemotherapy. Na,K‐ATPase is an ion pump well known for its role in intracellular ion homeostasis. Recent studies showed that Na,K‐ATPase also functions as a signaling platform and revealed a role in EGFR, MAPK, and PI3K signaling. While both EGFR and Na,K‐ATPase seem to modulate similar signaling pathways, cardiac glycosides that are steroid‐like inhibitors of Na,K‐ATPase, exhibit antiproliferative and proapoptotic properties in cancer cells. Thus, we sought to better understand the relationship between EGF and cardiac glycoside signaling. Here, we show that in medulloblastoma cells, both EGF and ouabain activate Erk1/2 and PI3K/Akt signaling. Nevertheless, in medulloblastoma cells ouabain did not transactivate EGFR as has been reported in various other cell lines. Indeed, ouabain inhibited EGF‐induced Erk1/2 and Akt activation and, moreover, prevented EGF‐induced formation of actin stress fibers and cell motility, probably by activating a stress signaling response. Na,K‐ATPase has been proposed to act as a signaling scaffold and our studies suggest that in medulloblastoma cells Na,K‐ATPase might act as a check point to integrate EGF‐associated signaling pathways. Thus, Na,K‐ATPase might serve as a valid target to develop novel therapeutic approaches in tumors with aberrant activation of the EGFR signaling cascades.
High‐Throughput Bead‐Based Identification of Structure‐Switching Aptamer Beacons
Authors: Trevino Simon G. , Levy Matthew
Published: July 2014

We describe a new platform to identify structure‐switching DNA beacon aptamers, which detect small molecules in a specific manner. By clonally amplifying a DNA library designed to fluoresce in response to binding events onto microbeads, aptamer beacons can be selected by stringent fluorescence‐assisted sorting. We validated this method by isolating known and novel anti‐steroid aptamers from two separate DNA libraries that were structurally enriched with three‐way junctions. Importantly, aptamers were retrieved in only a few (three) rounds of selection by this approach and did not require further optimization, significantly streamlining the process of beacon development.
Ectopic expression of DAZL gene in goat bone marrow‐derived mesenchymal stem cells enhances the trans‐differentiation to putative germ cells compared to the exogenous treatment of retinoic acid or bone morphogenetic protein 4 signalling molecules
Authors: Yan Guangyao , Fan Yixuan , Li Peizhen , Zhang YanLi , Wang Feng
Published: July 2014

The plasticity of human and murine bone marrow mesenchymal stem cells (BMSCs) has been proven by their ability to trans‐differentiate to multilineage cells, including germ cells. We have investigated ability of goat BMSCs to trans‐differentiate to germ cells with extrinsic (e.g., retinoic acid [RA] and BMP4 signalling molecules) and intrinsic factor expression (e.g., DAZL gene ectopic expression). Having optimized the concentration of RA and BMP4, gBMSCs were treated with RA 1 µM) and BMP4 (25 ng/mL), individually and collectively. Both RA and BMP4 induced OCT4, MVH, DAZL, STELLA, NANOG and C‐KIT expression, but RNF17, PIWIL2, STRA8, and SCP3 were only expressed after RA treatment. In terms of an endogenous factor, a germ cell specific gene, deleted in Azoospermia‐like (DAZL), was overexpressed by plasmid and mRNA techniques. Compared with the RA treated group, DAZL ectopic expression upregulated the transcription and translation of MVH, and SCP3 was also increased at the mRNA level. The mRNA‐based method had more effect on the germ cells gene expression compared to the plasmid method. Ectopic expression of the DAZL gene enhanced trans‐differentiation compared to the RA‐treated group. Knockdown experiments confirmed the pivotal role of DAZL in germ cell differentiation. This study provides further information on the mechanisms underlying the spermatogenesis, which will guide the derivation of post‐meiotic germ cells from adult stem cells in vitro.
p21‐activated kinase 7 is an oncogene in human osteosarcoma
Authors: Han Kun , Zhou Yan , Gan Zhi‐Hua , Qi Wei‐Xiang , Zhang Jian‐Jun , Fen Tao , Meng Wei , Jiang Ling , Shen Zan , Min Da‐Liu
Published: July 2014

p21‐activated kinase 7 (PAK7), also named as PAK5, is a member of Rac/Cdc42‐associated Ser/Thr protein kinases. It is overexpressed in some types of cancer such as colorectal and pancreatic cancers. However, the expression status and biological function of PAK7 in osteosarcoma are still ambiguous. To evaluate the expression levels of PAK7 in osteosarcoma tissues and cell lines, immunohistochemistry was used. To investigate the role of PAK7 in cell proliferation, apoptosis and tumorigenicity in vitro and vivo, a recombinant lentivirus expressing PAK7 short hairpin RNA (Lv‐shPAK7) was developed and transfected into Saos‐2 cells. The silencing effect of PAK7 was confirmed by quantitative real‐time PCR (qRT‐PCR) and Western blot technique. PAK7 was overexpressed in osteosarcoma tissue and cell line. By knocking‐down of PAK7, the proliferation and colony formation of Saos‐2 cells were inhibited and apoptosis enhanced significantly. The in vivo tumorigenic ability in xenograft model of Saos‐2 cells was also notably inhibited when PAK7 was knocked down. Our results imply that PAK7 promotes cell proliferation and tumorigenesis and may be an attractive candidate for the therapeutic target of osteosarcoma.
IL‐1β microenvironment promotes proliferation, migration, and invasion of human glioma cells
Authors: Fathima Hurmath K. , Ramaswamy Palaniswamy , Nandakumar Dalavaikodihalli Nanjaiah
Published: July 2014

Among the primary brain tumors, glioblastoma is the most common and severe. Glioblastoma have poor prognosis because of their highly diffusive growth pattern and invasion into surrounding brain tissue. Human glioblastoma cells overexpress interleukin‐1β (IL‐1β) and also the levels of IL‐1β in U87MG glioma cells are significantly higher than in U373, T98G, A172 glioma cell lines. Malignant tumors are characterized by unlimited proliferation, migration and invasion. This study examines the effect of IL‐1β microenvironment on proliferation, migration and invasion in human glioma cell line U87MG that expresses wild‐type p53 protein, and U251MG which expresses mutant p53. Proliferation was investigated by MTT assay, migration by wound‐healing migration assay and invasion by in vitro transwell Matrigel invasion assay. An IL‐1β microenvironment significantly increased migration and invasion of both wild‐type and mutant p53 expressing glioma cells, but significantly increased proliferation only in U87MG glioma cells. These effects were inhibited by IL‐1 receptor antagonist (IL‐1Ra), thus giving evidence that an IL‐1β milieu promotes glioma cell migration, invasion, and proliferation.
Nitrogen‐Doped Pitch‐Based Spherical Active Carbon as a Nonmetal Catalyst for Acetylene Hydrochlorination
Authors: Wang Xugen , Dai Bin , Wang Yang , Yu Feng
Published: July 2014

A highly active nitrogen‐doped pitch‐based spherical activated carbon catalyst (PSAC‐N) is synthesized through a nitrogen‐doping treatment and used as a nonmetal catalyst for acetylene hydrochlorination. The conversion of acetylene on PSAC‐N exceeds 68 % and the selectivity of vinyl chloride is over 99 % at a temperature of 250 °C, an acetylene gas hourly space velocity of 120 h−1, and a feed volume ratio V(HCl)/V(C2H2) of 1.15. DFT calculations performed with Gaussian 09 program package reveal that the active site of PSAC‐N has a N‐6v (quaternary nitrogen bonded between two 6‐membered rings) structure. A seven benzene ring unit model is used in the DFT study. In addition, the reason for inactivation for PSAC‐N catalysts is discussed. Of all the adsorption energies obtained, the adsorption capacity of hydrogen chloride on PSAC‐N is the highest, which indicates strong ability for acetylene hydrochlorination. The reaction mechanism is determined, and the reaction energy of N‐6v(7) calculated as 236.2 kJ mol−1.
ZnIn2S4: A Photocatalyst for the Selective Aerobic Oxidation of Amines to Imines under Visible Light
Authors: Ye Lin , Li Zhaohui
Published: July 2014

Flowerlike nanospheres of ZnIn2S4 consisting of interweaving nanoflakes were prepared by a rapid microwave‐assisted solvothermal method. The photocatalytic performance of ZnIn2S4 in the aerobic oxidation of amines to imines is for the first time revealed. As‐prepared ZnIn2S4 showed high efficiency for the transformations of various amines into their corresponding imines under visible‐light irradiation by using air as the oxidant. The photocatalytic performance of ZnIn2S4 in the selective oxidation of amines to their corresponding imines is much higher than that of graphitic C3N4 and CdS previously reported. A plausible mechanism involving the oxygenation of amines to form aldehydes, followed by the nucleophilic addition of the amines to afford the final imines is proposed. The use of a cheap, environmentally friendly inorganic semiconductor photocatalyst and solar energy makes this transformation green and sustainable.
Dynamics of the NbCl5‐Catalyzed Cycloaddition of Propylene Oxide and CO2: Assessing the Dual Role of the Nucleophilic Co‐Catalysts
Authors: D'Elia Valerio , Ghani Amylia A. , Monassier Antoine , Sofack‐Kreutzer Julien , Pelletier Jeremie D. A. , Drees Markus , Vummaleti Sai V. C. , Poater Albert , Cavallo Luigi , Cokoja Mirza , Basset Jean‐Marie , Kühn Fritz. E.
Published: July 2014

A mechanistic study on the synthesis of propylene carbonate (PC) from CO2 and propylene oxide (PO) catalyzed by NbCl5 and organic nucleophiles such as 4‐dimethylaminopyridine (DMAP) or tetra‐n‐butylammonium bromide (NBu4Br) is reported. A combination of in situ spectroscopic techniques and kinetic studies has been used to provide detailed insight into the reaction mechanism, the formation of intermediates, and interactions between the reaction partners. The results of DFT calculations support the experimental observations and allow us to propose a mechanism for this reaction.
Third‐Order Nonlinear Optical Properties of One‐Dimensional Open‐Shell Molecular Aggregates Composed of Phenalenyl Radicals
Authors: Yoneda Kyohei , Nakano Masayoshi , Fukuda Kotaro , Matsui Hiroshi , Takamuku Shota , Hirosaki Yuta , Kubo Takashi , Kamada Kenji , Champagne Benoît
Published: July 2014

The impact of intermolecular interactions on the third‐order nonlinear optical (NLO) properties of open‐shell molecular aggregates has been elucidated by considering one‐dimensional aggregates of π–π stacked phenalenyl radicals with different intermolecular distances and the long‐range corrected spin‐unrestricted density functional theory method. In the phenalenyl dimer, which can be considered as a diradicaloid system, the diradical character strongly depends on the intermolecular distance, and the larger the intermolecular distance is, the larger the diradical character becomes. Then, around the equilibrium stacking distance that corresponds to an intermediate diradical character, its second hyperpolarizability (γ) is maximized and its value per monomer exhibits about a 30‐fold enhancement with respect to the isolated phenalenyl monomer. This suggests that equilibrium is an optimal compromise between localization and delocalization of the radical electron pairs in such pancake bonding. No such effect was observed for the closed‐shell coronene dimer. Moreover, when going from the dimer (diradical) to the tetramer (tetraradical), the γ‐enhancement ratio increases nonlinearly with the aggregate size, whereas switching from the singlet to the highest spin (quintet) state causes a significant reduction of γ. Finally, for the tetramer, another one‐order enhancement of γ is achieved for the dicationic singlet relative to its singlet neutral state. These results demonstrate the key role of intermolecular π–π stacking interactions and charge in open‐shell (supra)molecular systems to achieve enhanced third‐order NLO properties.
Studies on [PtCl2]‐ or [AuCl]‐Catalyzed Cyclization of 1‐(Indol‐2‐yl)‐2,3‐Allenols: The Effects of Water/Steric Hindrance and 1,2‐Migration Selectivity
Authors: Qiu Youai , Fu Chunling , Zhang Xue , Ma Shengming
Published: July 2014

The [PtCl2]‐ or [AuCl]‐catalyzed reaction of 1‐(indol‐2‐yl)‐2,3‐allenols occurred smoothly at room temperature to afford a series of poly‐substituted carbazoles efficiently. Compared with the [PtCl2]‐catalyzed process, the [AuCl]‐catalyzed reaction represents a significant advance in terms of the scope and the selectivity. Selective 1,2‐alkyl or aryl migration of the gold carbene intermediate was observed: compared with the methyl group, the isopropyl, cyclopropyl, cyclobutyl, and cyclohexyl groups migrate exclusively; the cyclopropyl group shifts selectively over the ethyl group; the 1,2‐migration of a non‐methyl linear alkyl is faster than methyl group; the phenyl group migrates exclusively over methyl or ethyl group. DFT calculations show that water makes the elimination of H2O facile requiring a much lower energy and validates the migratory preferences of different alkyl or phenyl groups observed.
Determination of the Absolute Configuration of Perylene Quinone‐Derived Mycotoxins by Measurement and Calculation of Electronic Circular Dichroism Spectra and Specific Rotations
Authors: Podlech Joachim , Fleck Stefanie C. , Metzler Manfred , Bürck Jochen , Ulrich Anne S.
Published: July 2014

Altertoxins I–III, alterlosins I and II, alteichin (alterperylenol), stemphyltoxins I–IV, stemphyperylenol, stemphytriol, 7‐epi‐8‐hydroxyaltertoxin I, and 6‐epi‐stemphytriol are mycotoxins derived from perylene quinone, for which the absolute configuration was not known. Electronic circular dichroism (ECD) spectra were calculated for these compounds and compared with measured spectra of altertoxins I–III, alteichin, and stemphyltoxin III and with reported Cotton effects. Specific rotations were calculated and compared with reported specific rotations. The absolute configuration of all the toxins, except for stemphyltoxin IV, could thus be determined. The validity of the assignment was high whenever reported ECD data were available for comparison, and the validity was lower when the assignment was based only on the comparison of calculated and reported specific rotations. ECD spectra are intrinsically different for toxins with a biphenyl substructure and for toxins derived from dihydroanthracene.
ZSM‐5 Zeolite Nanosheets with Improved Catalytic Activity Synthesized Using a New Class of Structure‐Directing Agents
Authors: Kore Rajkumar , Srivastava Rajendra , Satpati Biswarup
Published: July 2014

A new series of multiquaternary ammonium structure‐directing agents, based on 1,4‐diazabicyclo[2.2.2]octane, was prepared. ZSM‐5 zeolites with nanosheet morphology (10 nm crystal thickness) were synthesized under hydrothermal conditions using multiquaternary ammonium surfactants as the zeolite structure‐generating agents. Both wide‐angle and small‐angle diffraction patterns were obtained using only a suitable structure‐directing agent under a specific zeolite synthesis composition. A mechanism of zeolite formation is proposed based on the results obtained from various physicochemical characterizations. ZSM‐5 materials were investigated in catalytic reactions requiring medium to strong acidity, which are important for the synthesis of a wide range of industrially important fine and specialty chemicals. The catalytic activity of ZSM‐5 materials was compared with that of the conventional ZSM‐5 and amorphous mesoporous aluminosilicate Al‐MCM‐41. The synthesis strategy of the present investigation using the new series of structure‐directing agents could be extended for the synthesis of other related zeolites or other porous materials in the future. Zeolite with a structural feature as small as the size of a unit cell (5–10 nm) with hierarchically ordered porous structure would be very promising for catalysis.
para‐Quinodimethane‐Bridged Perylene Dimers and Pericondensed Quaterrylenes: The Effect of the Fusion Mode on the Ground States and Physical Properties
Authors: Das Soumyajit , Lee Sangsu , Son Minjung , Zhu Xiaojian , Zhang Wenhua , Zheng Bin , Hu Pan , Zeng Zebing , Sun Zhe , Zeng Wangdong , Li Run‐Wei , Huang Kuo‐Wei , Ding Jun , Kim Dongho , Wu Jishan
Published: July 2014

Polycyclic hydrocarbon compounds with a singlet biradical ground state show unique physical properties and promising material applications; therefore, it is important to understand the fundamental structure/biradical character/physical properties relationships. In this study, para‐quinodimethane (p‐QDM)‐bridged quinoidal perylene dimers 4 and 5 with different fusion modes and their corresponding aromatic counterparts, the pericondensed quaterrylenes 6 and 7, were synthesized. Their ground‐state electronic structures and physical properties were studied by using various experiments assisted with DFT calculations. The proaromatic p‐QDM‐bridged perylene monoimide dimer 4 has a singlet biradical ground state with a small singlet/triplet energy gap (−2.97 kcal mol−1), whereas the antiaromatic s‐indacene‐bridged N‐annulated perylene dimer 5 exists as a closed‐shell quinoid with an obvious intramolecular charge‐transfer character. Both of these dimers showed shorter singlet excited‐state lifetimes, larger two‐photon‐absorption cross sections, and smaller energy gaps than the corresponding aromatic quaterrylene derivatives 6 and 7, respectively. Our studies revealed how the fusion mode and aromaticity affect the ground state and, consequently, the photophysical properties and electronic properties of a series of extended polycyclic hydrocarbon compounds.
Metalation of Polyamine Dendrimers with Ethynylcobalticenium for the Construction of Mono‐ and Heterobimetallic Polycationic Metallodendrimers
Authors: Wang Yanlan , Rapakousiou Amalia , Ruiz Jaime , Astruc Didier
Published: July 2014

The introduction of robust redox groups at the periphery of common amine‐terminated dendrimers is of interest in the design of dendritic nanobatteries, sensors, and redox catalysts. Here we are applying the recently discovered uncatalyzed hydroamination of ethynylcobalticenium, a mild “green” reaction that quantitatively yields trans‐enamines without the formation of any byproduct, to functionalize dendrimers that are terminated with primary or secondary amino groups. Poly(amido amine) (PAMAM) dendrimers terminated by primary amino groups and arene‐centered dendrimers terminated by secondary amino groups yield dendrimers that contain up to 81 trans‐enamine‐cobalticenium termini using this reaction. The hydroamination reaction was also conducted with dendrimers that contained ferrocenylmethylamino groups, which yielded dendrimers that contained both ferrocenyl and cobalticenium termini. The size of the dendrimers was investigated using both dynamic light scattering and diffusion‐ordered spectroscopy (DOSY) 1H NMR spectroscopy, and the number of electrons involved in heterogeneous multielectron transfers at electrodes was searched by cyclic voltammetry. The latter works well up to the 27‐branch dendrimer, whereas the 81‐dendrimer yielded a result in an excess amount (110 electrons) owing to adsorption onto the cathode that becomes all the more significant as the metallodendrimer size increases.
Double Metal Ions Competitively Control the Guest‐Sensing Process: A Facile Approach to Stimuli‐Responsive Supramolecular Gels
Authors: Lin Qi , Sun Bin , Yang Qing‐Ping , Fu Yong‐Peng , Zhu Xin , Wei Tai‐Bao , Zhang You‐Ming
Published: July 2014

A facile approach to the design of stimuli‐responsive supramolecular gels (SRSGs) termed double‐metal‐ion competitive coordination control is reported. By this means, the fluorescence signals and guest‐selective responsiveness of the SRSGs are controlled by the competitive coordination of two different metal ions with the gelators and the target guest. To demonstrate this approach, a gelator G2 based on multiple self‐assembly driving forces was synthesized. G2 could form Ca2+‐coordinated metallogel CaG with strong aggregation‐induced emission (AIE). Doping of CaG with Cu2+ results in AIE quenching of CaG and formation of Ca2+‐ and Cu2+‐based metallogel CaCuG. CaCuG could fluorescently detect CN− with specific selectivity through the competitive coordination of CN− with the Cu2+ and the coordination of Ca2+ with G2 again. This approach may open up routes to novel stimuli‐responsive supramolecular materials.
Direct Anisotropic Growth of CdS Nanocrystals in Thermotropic Liquid Crystal Templates for Heterojunction Optoelectronics
Authors: Yuan Kai , Chen Lie , Chen Yiwang
Published: July 2014

The direct growth of CdS nanocrystals in functional solid‐state thermotropic liquid crystal (LC) small molecules and a conjugated LC polymer by in situ thermal decomposition of a single‐source cadmium xanthate precursor to fabricate LC/CdS hybrid nanocomposites is described. The influence of thermal annealing temperature of the LC/CdS precursors upon the nanomorphology, photophysics, and optoelectronic properties of the LC/CdS nanocomposites is systematically studied. Steady‐state PL and ultrafast emission dynamics studies show that the charge‐transfer rates are strongly dependent on the thermal annealing temperature. Notably, annealing at liquid‐crystal state temperature promotes a more organized nanomorphology of the LC/CdS nanocomposites with improved photophysics and optoelectronic properties. The results confirm that thermotropic LCs can be ideal candidates as organization templates for the control of organic/inorganic hybrid nanocomposites at the nanoscale level. The results also demonstrate that in situ growth of semiconducting nanocrystals in thermotropic LCs is a versatile route to hybrid organic/inorganic nanocomposites and optoelectronic devices.
Label‐free Electrochemiluminescent Enantioselective Sensor for Distinguishing between Chiral Metallosupramolecular Complexes
Authors: Wu Li , Zhao Chuanqi , Ren Jinsong , Qu Xiaogang
Published: July 2014

Chiral molecular recognition of DNA is important for rational drug design and for developing structural probes of DNA conformation. Developing a convenient and inexpensive assay for sensitive and selective identification of DNA‐specific binding compounds with rapid, easy manipulation is in ever‐increasing demand. Here, we present a “turn‐on” and label‐free electrochemiluminescent (ECL) biosensor for distinguishing chiral metallosupramolecular complexes based on DNA three‐way junction formation selectively induced by the analyte. The fabricated ECL sensor shows excellent performance in the chiral discrimination of two enantiomers with an enantioselective recognition ratio of up to 4.4. More importantly, as a “turn‐on” detection system, the ECL chiral sensor does not suffer from false positives and limited signal range of “signal‐off” systems. Therefore, this concept may provide a new insight into the design of efficient sensors for distinguishing chiral molecules and for investigating the interactions between DNA and small molecules.
Removal of aluminum (III) from environmental samples by siliceous support grafted with poly[1‐(N,N‐bis‐carboxymethyl)amino‐3‐allylglycerol‐co‐dimethylacrylamide] brushes
Authors: Moniri Elham , Panahi Homayon Ahmad , Mohammadi Yasamin Ganbari , Gaforian Hossein
Published: July 2014

Silica gel was grafted with polymer containing a functional monomer for metal chelating, poly[1‐(N,N‐bis‐carboxymethyl)amino‐3‐allylglycerol‐co‐dimethylacrylamide] (poly(AGE/IDA‐co‐DMAA)). A system for preconcentration and measurement of aluminum as complexed with iminodiacetic acid was developed. The effects of the analytical parameters, such as sample pH, contact time on sorption capacity of the chelating sorbent and matrix ions, were investigated. The optimum pH value for sorption of the aluminum ions was 6. A recovery of 91.6 % was obtained for the metal ion with 0.5 mol L−1 sulphuric acid as eluting agent. The chelating resin can be reused for five cycles without any significant changes in sorption capacity. The sorption capacity of functionalised sorbent was 25.3 mg g−1. The developed method was utilized for preconcentration and determination of aluminum in environmental water samples by flame atomic absorption spectrometry with satisfactory results. The equilibrium adsorption data of Al(III) on modified sorbent were analysed by Langmuir, Freundlich and Temkin. Based on equilibrium adsorption data the Langmuir, Freundlich, Temkin and Redlich–Peterson constants were determined to be 0.076, 3.21, and 3.46, respectively, at pH 6 and 20 °C.
Parameters measurement of hydrodynamics and CFD simulation in multi‐stage bubble columns
Authors: Jin Haibo , Lian Yichen , Qin Ling , Yang Suohe , He Guangxiang , Guo Zhiwu
Published: July 2014

The effect of superficial gas velocity and structural parameters of plate (perforated plate and tongue plate) on the hydrodynamics parameters of column are studied in a multi‐stage bubble column, with 2000 mm height and 282 mm diameter of the multi‐stage bubble column, by using the electrical resistance tomography (ERT) technique and computational fluid dynamics (CFD). According to the results, ERT and CFD techniques can be well applied to the measurement and estimation of gas–liquid two‐phase processes. The gas holdups, the radial distribution of gas holdup and gas cap height strongly depend on the operating condition and tray structure. By increasing the superficial gas velocity, the gas holdup in the multi‐stage bubble column increases. With a decrease of the open area ratio, the hole diameter and tongue angle, the gas holdups and gas cap height below the perforated plate increase. The addition of the perforated plate enhances the flow behaviour of gas–liquid in bubble column. The CFD can then aid the prediction of gas cap height and gas holdup in a multi‐stage bubble column.
Radiotherapy for benign head and neck paragangliomas: A 45‐year experience
Authors: Gilbo Philip , Morris Christopher G. , Amdur Robert J. , Werning John W. , Dziegielewski Peter T. , Kirwan Jessica , Mendenhall William M.
Published: July 2014

BACKGROUND

Paragangliomas of the head and neck are rare, slow‐growing, generally benign tumors of neuroendocrine cells associated with the peripheral nervous system that commonly involve the carotid body, jugular bulb, vagal ganglia, and temporal bone. Treatment options include surgery, radiotherapy (RT), stereotactic radiosurgery (SRS), and observation. This article briefly reviews our 45‐year institutional experience treating this neoplasm with RT.

METHODS

From January 1968 through March 2011, 131 patients with 156 benign paragangliomas of the temporal bone, carotid body, jugular bulb, or glomus vagale were treated with RT at a median dose of 45 Gy in 25 fractions. The mean and median follow‐up times were 11.5 years and 8.7 years, respectively.

RESULTS

Five tumors (3.2%) recurred locally after RT, all within 10 years of treatment. The overall local control rates at 5 and 10 years were 99% and 96%, respectively. The cause‐specific survival rates at 5 and 10 years were 98% and 97%, respectively. The distant‐metastasis free survival rates at 5 and 10 years were 99% and 99%, respectively. The overall survival rates at 5 and 10 years were 91% and 72%, respectively. There were no severe complications.

CONCLUSION

RT for benign head and neck paragangliomas is a safe and efficacious treatment associated with minimal morbidity. Surgery is reserved for patients in good health whose risk of associated morbidity is low. SRS may be suitable for patients with skull base tumors <3 cm where RT is logistically unsuitable. Observation is a reasonable option for asymptomatic patients with a limited life expectancy. Cancer 2014;120:3738–3743. © 2014 American Cancer Society.
Effect of total dose and fraction size on survival of patients with locally recurrent nasopharyngeal carcinoma treated with intensity‐modulated radiotherapy: A phase 2, single‐center, randomized controlled trial
Authors: Tian Yun‐ming , Zhao Chong , Guo Ying , Huang Ying , Huang Shao‐Min , Deng Xiao‐Wu , Lin Cheng‐Guang , Lu Tai‐xiang , Han Fei
Published: July 2014

BACKGROUND

The optimal model of total dose and fraction size for patients with locally recurrent nasopharyngeal carcinoma treated with intensity‐modulated radiotherapy (IMRT) remains unclear. The authors designed a randomized phase 2 clinical trial to investigate the efficacy of 2 different models, with the objective of determining an optimal model.

METHODS

Between January 2003 and December 2007, a total of 117 patients with locally recurrent nonmetastatic nasopharyngeal carcinoma were randomized to 2 different models of total dose and fraction size: group A (59 patients) received 60 gray in 27 fractions and group B (58 patients) received 68 gray in 34 fractions. Both groups received 5 daily fractions per week. All patients received IMRT alone.

RESULTS

The median follow‐up was 25.0 months. The 5‐year overall survival in group A was higher than that in group B (44.2% vs 30.3%; P =.06), and the local failure‐free survival in group A was slightly lower than that in group B (63.7% vs 71.0%; P =.41). Severe late complications were the main cause of death. The incidences of mucosal necrosis and massive hemorrhage in patients in group B were significantly higher than those among patients in group A at 50.8% versus 28.8% (P =.02) and 31.0% versus 18.6% (P =.12), respectively. Tumor volume (P<.01) and model of total dose and fraction size (P =.03) were found to be significant factors for mucosal necrosis and massive hemorrhage.

CONCLUSIONS

Appropriately decreasing the total dose and increasing the fraction size can achieve local control similar to that achieved with a higher dose after IMRT; furthermore, it can improve overall survival by significantly reducing the incidence of severe late complications including mucosal necrosis and massive hemorrhage. Cancer 2014;120:3502–3509. © 2014 American Cancer Society.
Effects of Oil on Aqueous Foams: Electrical Conductivity of Foamed Emulsions
Authors: Yan Yong‐Li , Shan Cheng , Wang Yao , Deng Qiang
Published: July 2014

Three‐phase foams containing dispersed oils (also called foamed emulsion) are usually encountered in such areas as enhanced oil recovery, food foams, and in foams containing antifoams. The presence of oil causes these complex fluids to exhibit extraordinary properties in contrast to aqueous foams. We experimentally investigated, for the first time, the conductive properties of the foamed emulsions and found that the electrical conductivity increases monotonically with the volumetric liquid fraction, presenting a linear relationship. Combined with the analysis on the foaming capacity and microstructure of this complex fluid, the conductive mechanism is revealed. In these foamed emulsions, the whole conductive network is comprised of two levels of structural hierarchy, which displays a different mechanism from those of the conventional aqueous foams. The lamella of emulsions is taken as primary electrical channel, whereas the secondary electrical channel occurs in the lamella between two bubbles. This conductive behaviour is attributed to the microstructure properties of the foamed emulsions. We believe that such findings are potentially important for a better understanding of the fundamentals of these tri‐phase dispersion systems.