bluuebunny/crossref_metadata_2025_split huggingface dataset:
12‐Membered Macrocycles Containing Ditelluroxane and Selenotelluroxane Units
Authors: Srungavruksham Nagarjuna Kumar , Baskar Viswanathan 
Published: November 2011

AbstractThe reaction of benzeneseleninic acid with bis(p‐methoxyphenyl)tellurium dihalide [halide = Cl (1), Br (2)] afforded colorless crystals in moderate yield. Single‐crystal X‐ray diffraction revealed the formation of 12‐membered macrocycles [(p‐MeO‐C6H4)2Te(μ‐O)(μ‐PhSeO2)(μ4‐X)]2 [X = Cl (1), Br (2)] where the halogen atoms, which are stabilized by Te–X interactions, cap the macrocycle on both sides. The reaction of NaI with 1 afforded the iodo‐capped macrocycle [(p‐MeO‐C6H4)2Te(μ‐O)(μ‐PhSeO2)(μ4‐I)]2 (3) in good yield. In the solid‐state structures of 1–3, the alignment of the phenyl group on Se changes with respect to the macrocycle. Macrocycle 3 shows rare Se–π interactions, which lead to the formation of a supramolecular polymeric network. Further reaction of methaneseleninic acid with bis(p‐methoxyphenyl)tellurium dichloride in methanol in the presence of triethylamine afforded a 12‐membered macrocycle [(p‐MeO‐C6H4)2Te(μ‐O)(μ‐MeSeO2)(μ4‐Cl)]2 (4), which is structurally similar to 1–3.
High Performance Liquid Chromatography‐Electrochemistry‐Electrospray Ionization Mass Spectrometry (HPLC/EC/ESI‐MS) for Detection and Characterization of Roscovitine Oxidation Products
Authors: Karady Michal , Novák Ondřej , Horna Aleš , Strnad Miroslav , Doležal Karel 
Published: November 2011

AbstractOn‐line LC‐EC/ESI‐MS has been established as a fast and simple method to mimic some types of oxidation reaction of various drugs and to study the formation and structure of the resulting products. This technique has been applied to a 2,6,9‐trisubstituted purine, R‐roscovitine, which is known to be an inhibitor of some cyclin‐dependent kinases (CDKs) and a potential anticancer drug. Oxidation of R‐roscovitine in an electrochemical cell (EC), operated under various conditions, resulted in appearance of 6 major products. These were further analyzed by high‐resolution mass spectrometry, their structures were elucidated by accurate mass measurement and compared to previously identified R‐roscovitine in vitro/in vivo metabolites. Although none of the observed products was structurally identical to those identified previously in vitro/in vivo, all of them, except for the methoxylated products, resembled similarity due to appearing through the same reaction type. R‐roscovitine in the EC cell underwent N‐dealkylation of the isopropyl moiety, hydroxylation of the aromatic side‐chain, dihydroxylation, methoxylation and dimer formation. The hydroxylation product was identified as Olomoucine II, a R‐roscovitine derivative, which displays 10‐times higher CDK‐inhibiting activity than R‐roscovitine and the occurrence of which, as R‐roscovitine product, has not yet been observed in vitro/in vivo.
Ovarian steroid cell tumor with biallelic adenomatous polyposis coli inactivation in a patient with familial adenomatous polyposis
Authors: Hu Patrick J. , Knoepp Stewart M. , Wu Rong , Cho Kathleen R. 
Published: November 2011

AbstractFamilial adenomatous polyposis (FAP) is an autosomal dominant cancer predisposition syndrome that accounts for approximately 0.5–1% of all colorectal cancer cases. It is caused by germline mutations in the gene encoding the adenomatous polyposis coli (APC) tumor suppressor. Somatic APC inactivation due to mutation or loss of heterozygosity (LOH) promotes the development of adenomatous polyps by stabilizing the transcriptional coactivator β‐catenin. Although colorectal cancer is by far the most common malignancy seen in FAP patients, the widespread use of prophylactic colectomy in these patients has increased the clinical importance of extracolonic tumors that are part of the neoplastic spectrum in FAP. Many of these tumors exhibit LOH or somatic APC mutation, strongly supporting a causative role of APC inactivation in their pathogenesis. Here we describe a 47‐year‐old female FAP patient with clinical manifestations of virilization who was found to have an ovarian steroid cell tumor, a rare neoplasm not known to be associated with FAP. Immunohistochemical analysis of the ovarian tumor demonstrated strong nuclear β‐catenin staining consistent with somatic APC inactivation, and molecular analysis confirmed biallelic APC inactivation in the tumor. Our findings provide the first evidence that ovarian steroid cell tumors may be an extracolonic manifestation of FAP and implicate β‐catenin activation as an oncogenic mechanism in ovarian steroid cell tumorigenesis. © 2011 Wiley Periodicals, Inc.
Molecular analysis of the t(2;8)/MYC–IGK translocation in high‐grade lymphoma/leukemia by long‐distance inverse PCR
Authors: Kroenlein Hannes , Schwartz Stefan , Reinhardt Richard , Rieder Harald , Molkentin Mara , Gökbuget Nicola , Hoelzer Dieter , Thiel Eckhard , Burmeister Thomas 
Published: November 2011

AbstractBurkitt lymphoma and a subset of diffuse large B‐cell lymphomas are characterized by chromosomal alterations affecting the MYC oncogene on 8q24. In most cases MYC is found juxtaposed to the immunoglobulin heavy chain (IGH) gene locus. Translocations to the immunoglobulin kappa (IGK) gene locus on 2p11 are observed in around 5–10% of cases. Little data exist on the molecular mechanisms leading to this aberration. The chromosomal breakpoints on chromosome 8 have been found dispersed over a large area 3′ of MYC. In order to obtain a better understanding of this chromosomal translocation we developed a long‐distance inverse (LDI) PCR method for the identification of chromosomal translocations affecting the IGK locus. We investigated a number of cytogenetically mostly uncharacterized high‐grade lymphoma samples and identified a MYC–IGK juxtaposition in seven patients and three t(2;8)‐positive cell lines. The chromosomal breakpoints were molecularly characterized and analyzed. The linear distance of the breakpoints on chromosome 8 to MYC ranged from some 100 bp to more than 0.5 MB. The reciprocal translocated allele could be characterized in the majority of cases. This study represents the largest series of t(2;8)‐positive cases analyzed so far. The LDI PCR method developed here should also be useful for the analysis of chromosomal translocations affecting the IGK locus in general. © 2011 Wiley Periodicals, Inc.
Aberrations in the arcuate fasciculus are associated with auditory verbal hallucinations in psychotic and in non‐psychotic individuals
Authors: de Weijer Antoin D. , Neggers Sebastiaan F.W. , Diederen Kelly M.S. , Mandl René C.W. , Kahn René S. , Hulshoff Pol Hilleke E. , Sommer Iris E. 
Published: November 2011

AbstractThe pathophysiology of auditory verbal hallucinations (AVH) is still unclear. Cognitive as well as electrophysiological studies indicate that a defect in sensory feedback (corollary discharge) may contribute to the experience of AVH. This could result from disruption of the arcuate fasciculus, the major tract connecting frontal and temporo‐parietal language areas. Previous diffusion tensor imaging studies indeed demonstrated abnormalities of this tract in schizophrenia patients with AVH. It is, however, difficult to disentangle specific associations with AVH in this patient group as many other factors, such as other positive and negative symptoms, medication or halted education could likewise have affected tract integrity. We therefore investigated AVH in relative isolation and studied a group of non‐psychotic individuals with AVH as well as patients with AVH and non‐hallucinating matched controls. We compared tract integrity of the arcuate fasiculus and of three other control tracts, between 35 non‐psychotic individuals with AVH, 35 schizophrenia patients with AVH, and 36 controls using diffusion tensor imaging and magnetization transfer imaging. Both groups with AVH showed an increase in magnetization transfer ratio (MTR) in the arcuate fasciculus, but not in the other control tracts. In addition, a general decrease in fractional anisotropy (FA) for almost all bundles was observed in the patient group, but not in the non‐psychotic individuals with AVH. As increased MTR in the arcuate fasciculus was present in both hallucinating groups, a specific association with AVH seems plausible. Decreases in FA, on the other hand, seem to be related to other disease processes of schizophrenia. Hum Brain Mapp, 2013. © 2011 Wiley Periodicals, Inc.
Gelation time, homogeneity, and rupture testing of alginate‐calcium carbonate‐hydrogen peroxide gels for use as wound dressings
Authors: Alexander Brendan R. , Murphy Kathleen E. , Gallagher Joanne , Farrell Garrett F. , Taggart Gertie 
Published: November 2011

AbstractThe care of chronic wounds carries a heavy financial burden on the healthcare industry, with billons being spent annually on their treatment. This, coupled with a decreased quality of life for sufferers, has led to a real urgency in developing inexpensive wound dressings that promote wound healing. Alginate gels for application as wound dressings were formed by varying alginate (0%–6% w/v), calcium carbonate (0%–1% w/v), hydrogen peroxide (0%–3.75% v/v), and hyaluronic acid (0–1.25 mg/L) content. The aging effects on the physical properties of the gels over a 14‐day period were also investigated. The results indicated that the concentration of calcium carbonate and hydrogen peroxide, as well as sample age, all had a significant effect on the rupture characteristics and gelation time of the gels. Increased calcium carbonate content caused an increase in rupture force and rupture energy values, whereas increased hydrogen peroxide content and sample age resulted in a decrease in rupture force and rupture energy measurements. Increased calcium carbonate and hydrogen peroxide content produced a decrease in the time required for gel formation. Statistical models were also produced to provide a means of estimating rupture characteristics and gelation times for gels containing other concentrations of these components. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 100B: 425–431, 2012.
Inhibition of GPR40 protects MIN6 β cells from palmitate‐induced ER stress and apoptosis
Authors: Wu Jinwei , Sun Peng , Zhang Xiaodong , Liu Hong , Jiang Hualiang , Zhu Weiliang , Wang Heyao 
Published: November 2011

AbstractChronic exposure to elevated concentration of free fatty acids (FFA) has been verified to induce endoplasmic reticulum (ER) stress, which leads to pancreatic β‐cell apoptosis. As one of the medium and long chain FFA receptors, GPR40 is highly expressed in pancreatic β cells, mediates both acute and chronic effects of FFA on β‐cell function, but the role of GPR40 in FFA‐induced β‐cell apoptosis remains unclear. In this study, we investigated the possible effects of GPR40 in palmitate‐induced MIN6 β‐cell apoptosis, and found that DC260126, a novel small molecular antagonist of GPR40, could protect MIN6 β cells from palmitate‐induced ER stress and apoptosis. Similar results were observed in GPR40‐deficient MIN6 cells, indicating that palmitate‐induced β‐cell apoptosis is at least partially dependent on ER stress pathway via GRP40. J. Cell. Biochem. 113: 1152–1158, 2012. © 2011 Wiley Periodicals, Inc.
Accelerating molecular monte carlo simulations using distance and orientation‐dependent energy tables: Tuning from atomistic accuracy to smoothed “coarse‐grained” models
Authors: Lettieri Steven , Zuckerman Daniel M. 
Published: November 2011

AbstractTypically, the most time consuming part of any atomistic molecular simulation is the repeated calculation of distances, energies, and forces between pairs of atoms. However, many molecules contain nearly rigid multi‐atom groups such as rings and other conjugated moieties, whose rigidity can be exploited to significantly speed‐up computations. The availability of GB‐scale random‐access memory (RAM) offers the possibility of tabulation (precalculation) of distance‐ and orientation‐dependent interactions among such rigid molecular bodies. Here, we perform an investigation of this energy tabulation approach for a fluid of atomistic—but rigid—benzene molecules at standard temperature and density. In particular, using
${\cal O}$(1) GB of RAM, we construct an energy look‐up table, which encompasses the full range of allowed relative positions and orientations between a pair of whole molecules. We obtain a hardware‐dependent speed‐up of a factor of 24–50 as compared to an ordinary (“exact”) Monte Carlo simulation and find excellent agreement between energetic and structural properties. Second, we examine the somewhat reduced fidelity of results obtained using energy tables based on much less memory use. Third, the energy table serves as a convenient platform to explore potential energy smoothing techniques, akin to coarse‐graining. Simulations with smoothed tables exhibit near atomistic accuracy while increasing diffusivity. The combined speed‐up in sampling from tabulation and smoothing exceeds a factor of 100. For future applications, greater speed‐ups can be expected for larger rigid groups, such as those found in biomolecules. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2012
Structure and properties of the aluminum borates Al(BO2)n and Al(BO2)n−, (n = 1–4)
Authors: Gutsev Gennady L. , Weatherford Charles A. , Johnson Lewis E. , Jena Purusottam 
Published: November 2011

AbstractThe geometrical and electronic structures of Al(BO2)n and Al(BO2)n− (n = 1–4) clusters are computed at different levels of theory including density functional theory (DFT), hybrid DFT, double‐hybrid DFT, and second‐order perturbation theory. All aluminum borates are found to be quite stable toward the BO2 and BO2− loss in the neutral and anion series, respectively. Al(BO2)4 belongs to the class of hyperhalogens composed of smaller superhalogens, and should possess a large adiabatic electron affinity (EAad) larger than that of its superhalogen building block BO2. Indeed, the aluminum tetraborate possesses the EAad of 5.6 eV, which, however, is smaller than the EAad of 7.8 eV of the AlF4 supehalogen despite BO2 is more electronegative than F. The EAad decrease in Al(BO2)4 is due to the higher thermodynamic stability of Al(BO2)4 compared to that of AlF4. Because of its high EA and thermodynamic stability, Al(BO2)4 should be capable of forming salts with electropositive counter ions. We optimized KAl(BO2)4 as corresponding to a unit cell of a hypothetical KAl(BO2)4 salt and found that specific energy and energy density of such a salt are competitive with those of trinitrotoluol (TNT). © 2011 Wiley Periodicals, Inc. J Comput Chem, 2012
Gold Nanoparticle‐electrodeposited Electrodes Used for p‐Nitrophenol Detection in Acidic Media: Effect of Electrodeposition Parameters on Particle Density, Size Distribution, and Electrode Performance
Authors: Tang Ying‐Yao , Chen Po‐Yu 
Published: November 2011

AbstractPara‐nitrophenol (p‐NP) was detected using gold nanoparticle‐electrodeposited indium tinoxide electrodes (AuNP‐ITO) or AuNP‐electrodeposited screen printing carbon electrodes (AuNP‐SPC) in acidic media. AuNPs were formed by potential‐sweeping electrodeposition from the solution containing Na2SO4, H2SO4, and HAuCl4·3H2O. The effect of electrodeposition parameters, such as the cycling number of potential scan, the cathodic switching potential, and the scan rate, on density and size distribution of AuNPs was studied. It was found that the particle density and the size distribution of the AuNPs had a crucial effect on the electrode activity to p‐NP reduction. A AuNP‐electrodeposited electrode with appropriate size, narrow distribution, and high density of AuNPs shows the best activity to p‐NP reduction. p‐NP was detected by hydrodynamic chronoamperometry at –0.2 V and the dependence of the steady state current taken from the amperometric transient on concentration of p‐NP was linear from 1.0 × 10–7 M to 3.15 × 10–4 M with a regression coefficient of 0.9995. The detection limit was 9.8 × 10–8 M (13.7 ppb) (σ = 3).
Selective Tellurium Nanowire‐based Sensors for Mercury(II) in Aqueous Solution
Authors: Wei Tsao‐Yen , Chang Hsin‐Yun , Lee Yen‐Fei , Hunga Yu‐Lun , Huang Chih‐Ching 
Published: November 2011

AbstractWe have developed a simple, colorimetric, and label‐free tellurium nanowire (Te NW)‐based probe for the detection of mercury ions (Hg(II)) in aqueous solution, operating on the principle of strong hybridization and galvanic replacement reaction of Te–Hg. The Te NWs (length: 920 nm; diameter: 20 nm) reacted with Hg(II) to induce dissolution and aggregation of the Te NWs. As a result, the absorption band of the Te NWs in a solution undergoes a decrease in the presence of Hg(II). Energy‐dispersive X‐ray spectroscopy and surface‐assisted laser desorption/ionization measurements demonstrated the presence of Hg on the Te NWs. The Te NW probe specifically and sensitively detected Hg(II) ions under optimal concentrations of pH, temperature, and sodium dodecyl sulfate (SDS) concentration. When using a mixture of Te NWs (3.0 nM) and SDS (5 μM) in 5 mM sodium phosphate (pH 4) at 50 °C, this sensor provides a limit of detection of 0.5 nM for Hg(II) (signal‐to‐noise ratio of 3) with high selectivity (at least 100 fold over other metal ions). Our approach abrogates the need for complicated chemosensors or sophisticated equipment. This cost‐effective sensing system allows the rapid and simple determination of the concentrations of Hg(II) ions in real samples (in this case, river, lake, and tap water samples).
Silver Nanoparticles as a Glucose Oxidase Immobilization Matrix for Amperometric Glucose Biosensor Construction
Authors: Hsu Fu‐Yin , Yu Ding‐Syuan , Chang Jung‐Che , Chuang Chia‐Lin 
Published: November 2011

AbstractImmobilized biomolecules are widely applied in medical, food and environmental fields. In this paper, glucose oxidase (GOD) was covalently immobilized on the surface of thiol‐modified silver nanoparticles (AgNPs) to fabricate GOD‐AgNP bioconjugate complexes. GOD‐AgNP complex were more stable at high temperature and in high pH environments than the free GOD in solution. Additionally, the fabricated Carbon rod/GOD‐AgNPs/Nafion/Chitosan electrode exhibited a rapid response and a linear calibration range from 0.5 mM to 6 mM for the detection of glucose. The Nafion/Chitosan coating could eliminate common interferents, such as uric acid and acetaminophen. As a conclusion, the experimental results indicated that the resulting modified electrode possesses an excellent response performance on glucose.
Analysis of Biomolecules through Surface‐Assisted Laser, Desorption/Ionization Mass Spectrometry Employing Nanomaterials
Authors: Chen Wen‐Tsen , Tomalová Iva , Preisler Jan , Chang Huan‐Tsung 
Published: November 2011

AbstractNanomaterials, primarily nanoparticles (NPs), can serve as an alternative matrix for the analysis of various biomolecules through surface‐assisted laser desorption/ionization mass spectrometry (SALDI MS). SALDI MS has been developed to overcome poor reproducibility and high background in the lowmass region commonly occurring in matrix‐assisted laser desorption/ionization mass spectrometry (MALDI MS). Various nanomaterials, unmodified or functionalized with recognition ligands, can have a strong affinity toward certain analytes and thus are applicable for their concentration and enrichment from complex biological matrices. In mass spectrometry imaging (MSI), the use of NPs instead of the conventional matrices can improve the spatial resolution up to the cellular level. In this review, the nature of NPs, the methods of sample preparation and approaches for quantitation of biomolecules through SALDI MS are discussed. Practical applications and limitations of SALDI MS employing NPs for separate samples and MSI are mentioned. With regard to the nature of MSI analysis, the use of nanostructured surfaces for MSI is also reflected in this review.
A Fiber Optic Particle Plasmon Resonance Biosensing Platform Based on Detection of Light Scattering Intensity from the Proximal End
Authors: Chau Lai‐Kwan , Kuo Chia‐Wen , Chu Ya‐Wei , Liao Shin‐Hsien , Lin Yung‐Tai , Wang C. R. Chris 
Published: November 2011

AbstractA novel light scattering sensing platform was constructed on the basis of modification of the unclad portion of an optical fiber with self‐assembled gold nanoparticles. The light scattering signal from the sensor fiber can be collected from the side surface or from the proximal end. In general, collection from the proximal end is more sensitive and the sensitivity increases with increasing sensor length. When excited at 673 nm, the light scattering signal from the sensor fiber increases linearly with increasing refractive index of samples. This change in the light scattering property of a gold nanoparticle in solutions of different refractive indexes has been confirmed by simulations. Furthermore, the gold nanoparticle surface was functionalized with L‐cysteine or biotin to allow selectivity of the sensor. With excitation at 442 nm, results show that the light scattering signal increases linearly with increasing concentration of each analyte. Detection limits of the sensor for Cu2+ ion and streptavidin were determined to be 0.16 ppb and 3.3 × 10‐10 M, respectively. This label‐free biosensing capability has also been confirmed by simulations of the scattering cross‐sections of biotin‐modified gold nanoparticles at various surface coverages of streptavidin.
Determination of Paraquat and Diquat by Combination of Nanoparticles‐Based Extraction with Capillary Electrophoresis
Authors: Chu Hui‐Ping , Chang Sarah Y. 
Published: November 2011

AbstractSilica nanoparticles (SiNPs) have been used as concentrating probes to extract paraquat and diquat from aqueous solution before capillary electrophoretic analysis. Adsorption of paraquat and diquat onto SiNPs is mainly through electrostatic interaction. After extraction and centrifugation, the analytes were eluted from the surface of SINPs by rinsing with acetic acid solution. The extract was directly analyzed by capillary electrophoresis with UV absorption detection. Using SiNPs to concentrate the analytes from 10 mL of aqueous solution, the enrichment factors for paraquat and diquat were 75 and 192, respectively. The limits of detection (LODs) at signal‐to‐noise ratio of 3 were 0.03 and 0.05 μM for paraquat and diquat, respectively. This developed method was applied to the determination of paraquat in mung bean. The LOD of paraquat in mung bean was 0.1 μg/g.
Recent Advances in Dynamic Monitoring of Drug Release of Nanoparticle Using Förster Resonance Energy Transfer and Fluorescence Lifetime Imaging
Authors: Cheng Shih‐Hsun , Chen Nai‐Tzu , Wu Chia‐Yan , Chung Chao‐Yu , Hwu Yeukuang , Mou Chung‐Yuan , Yang Chung‐Shi , Lo Leu‐Wei 
Published: November 2011

AbstractIn this review, we summarized the recent advances in dynamic monitoring of drug release of nanoparticle using FRET and FLIM. Using FRET to understanding the dynamics of drug released from its nanocarrier within intracellular milieu provides high sensitivity and temporal information of the releasing profile. Such information is crucial for the design of drug carriers and validation of drug controlled release. This approach thus has been prevailingly used in monitoring of drug release from a variety of DDS, including quantum dot‐, polymer‐, and silica‐based delivery systems. Alternatively, FLIM assessing changes of micro‐environment of drug possesses great potential for use in profiling the intracellular drug release and subcellular drug distribution with various DDS. Our recent approach using FLIM for mapping the intracellular Dox released from pH‐responsive MSN has exemplified the feasibility of delineating subcellular distribution of fluorescent drug with corresponding variation of fluorescence lifetime. Both FRET and FLIM are emerging as important techniques in assessing the efficiency of targeted delivery and controlled release of drug with different nanodelivery systems.