bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substantial Spatial Flexibility and Hydrogen Bonding within the Catalysis Exerted by Cyclodextrin Artificial Glycosidases
Authors: Bjerre Jeannette , Bols Mikael 
Published: May 2010

AbstractHerein we report the synthesis of a novel 7A,7D‐dicyanohydrin‐β‐cyclodextrin that catalyzes the hydrolysis of aryl glycosides with up to 5500 times rate increase (kcat/kuncat), functioning as a glycosidase enzyme mimic. For all glycoside substrates tested at 50 mM phosphate buffer this catalysis is superior to previously reported results for 6A,6D‐dicyanohydrin cyclodextrin (CD) artificial glycosidases, i.e. analogues which have their catalytic group one carbon atom closer to the cyclodextrin cavity. This provides proof of substantial flexibility within the catalysis exerted by these CD chemzymes. A series of permethylated mono‐ and dicyanohydrin α‐ and β‐CDs were also synthesized, and these showed more modest catalytic rate enhancements of up to 110 times (10 % catalysis rate, relative to non‐methylated analogues), implying that the permethylation blocks or hampers catalytically important binding between the saccharide part of the substrate and the CD. For comparison, the permethylated 6A,6D‐dicarboxylic acid β‐CD was also synthesized and afforded 25 % activity (up to 250 times rate increase) relative to the nonpermethylated 6A,6D‐dicarboxylic acid β‐CD. This suggests that the catalytic effect of the polar interactions of the ionized carboxylate entity is less dependent on the substrate position. These findings afford new information on the scopes and boundaries for CD artificial glycosidase catalysis, and the spatial flexibility discovered fosters optimism for future advances and discoveries within the field of artificial enzymes.
Bienzyme Sensor Based on an Oxygen Reducing Bilirubin Oxidase Electrode
Authors: Göbel G. , Dietz T. , Lisdat F. 
Published: May 2010

AbstractBased on an oxygen reducing electrode combining bilirubin oxidase and multiwalled carbon nanotubes modified gold (BOD‐MWCNT‐Au electrode) a bienzyme sensor is developed. Therefore the BOD‐MWCNT‐Au electrode is covalently coupled to enzymes catalysing oxygen‐consuming reactions (glucose oxidase and ascorbate oxidase) to result in a membrane‐free bienzyme electrode. The electrochemical characterisation of these bienzyme sensors reveals an enzyme substrate sensitivity down to 250 μM glucose and 100 μM ascorbate. In addition, the assembled sensor systems allow amperometric measurements in a potential range where the influence of interfering substances reacting directly at the transducing electrode is minimised. The results indicate that the BOD electrode provides a suitable platform for sensing analytes of medical and environmental interest for which oxidases of high activity are available.
Simultaneous Determination of Dihydroxybenzene Isomers Using Preanodized Inlaying Ultrathin Carbon Paste Electrode
Authors: Wang Zhenhui , Sun Zhidan , Zhu Hefeng , Gao Guiqin , Liu Haiping , Zhao Xiaoling 
Published: May 2010

AbstractIn this paper, we described a rapid, sensitive and selective method for simultaneous voltammetric determination of dihydroxybenzene isomers with a preanodized inlaying ultrathin carbon paste electrode (PAIUCPE). Scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and voltammetry were employed to characterize the configuration and electrochemical properties of the electrode. The resulting PAIUCPE exhibited excellent recognition ability towards dihydroxybenzene isomers. Three well‐defined oxidation peaks of catechol (CC), resorcinol (RC) and hydroquinone (HQ) can be identified entirely at the electrode. The oxidation peak potential difference between HQ and CC was 120 mV, CC and RC 430 mV, respectively. The peak currents increased linearly with increasing the concentration of dihydroxybenzene isomers. The proposed electrode can be applied to simultaneous determination of dihydroxybenzene isomers without previous chemical or physical separations.
Sensitive Superoxide Biosensor Based on Silicon Carbide Nanoparticles
Authors: Rafiee‐Pour Hossain‐Ali , Noorbakhsh Abdollah , Salimi Abdollah , Ghourchian Hedayatollah 
Published: May 2010

AbstractDirect electron transfer of immobilized superoxide dismutase (Cu, Zn‐SOD) onto silicon carbide (SiC) nanoparticles displays a pair of well defined and nearly reversible redox peaks with formal potential (E°′) of −0.03 V in pH 7.4. The heterogeneous electron transfer rate constant (ks) and surface coverage (Γ) of immobilized SOD are 11.0±0.4 s−1 and 1.42×10−11 mol cm−2. Biosensor shows fast amperometric response (3s) with sensitivity and detection limit of 1.416 nA μM−1, 1.66 μM, and 1.375 nA μM−1, 2.1 μM for cathodically or anodically detection of superoxide, respectively. This biosensor also exhibits good stability, reproducibility and long life‐time.
Electrochemical and Optical Behavior of 8‐Hydroxypyrene‐1,3,6‐trisulfonic Acid at Optically Transparent Electrodes
Authors: Andrews Ronnee N. , Seliskar Carl J. , Heineman William R. 
Published: May 2010

AbstractThe objective of this work is to elucidate the electrochemical and corresponding optical properties of 8‐hydroxypyrene‐1,3,6‐trisulfonic acid (HPTS), using optically transparent electrodes, thereby deducing its usefulness as a model compound for spectroelectrochemical sensor development. Three pH levels were tested to determine optimal solution conditions for optical signal modulation. The electrolysis of HPTS follows an ECE mechanism, presumably resulting in the formation of a dihydroxy/dione derivative, and modulates the optical response at 405 and 460 nm wavelengths for pH 5 solutions. HPTS is a good candidate for spectroelectrochemical sensor research.
Advances in the Study of Ion Transfer at Liquid Membranes with Two Polarized Interfaces by Square Wave Voltammetry
Authors: Molina A. , Ortuño J. A. , Serna C. , Torralba E. , Gonzalez J. 
Published: May 2010

AbstractA general analytical expression has been deduced for the I/E response of the square wave voltammetry corresponding to ion transfer processes in systems with two liquid/liquid polarized interfaces. This expression has been evaluated through the experimental study of a series of quaternary ammonium cations and metal chloro complex anions. We have found that systems with two liquid/liquid polarizable interfaces present the striking advantage that the difference between peak potentials of square wave voltammograms of cations and anions with similar standard ion transfer potential is much greater than in systems with a single polarizable one.
Carbonized Hemoglobin Nanofibers for Enhanced H2O2 Detection
Authors: Ding Yu , Jia Wenzhao , Zhang Heng , Li Baikun , Gu Zhiyong , Lei Yu 
Published: May 2010

AbstractElectrospun hemoglobin (Hb) microbelts were used as a novel precursor to produce a new class of carbon nanofibers (Hb‐CNFs) containing Fe species (Fe2O3 and/or Fe‐N4 moiety). The Hb‐CNFs modified glassy carbon electrode (Hb‐CNFs/GCE) exhibits significant oxidation/reduction towards H2O2. The observed H2O2 oxidation/reduction starting at ca. +0.26 V and +0.15 V (vs. Ag/AgCl) are significantly lower than the values observed at other CNFs modified GCE. The Hb‐CNFs/GCE was also applied to the amperometric detection of H2O2 and the results showed fast response, high sensitivity, excellent reproducibility, good selectivity, and wide dynamic range with good limit of detection.
Selective Electroanalysis of Ascorbic Acid Using a Nickel Hexacyanoferrate and Poly(3,4‐ethylenedioxythiophene) Hybrid Film Modified Electrode
Authors: Tsai Tsung‐Hsuan , Chen Tse‐Wei , Chen Shen‐Ming 
Published: May 2010

AbstractThe mixed‐valent nickel hexacyanoferrate (NiHCF) and poly(3,4‐ethylenedioxythiophene) (PEDOT) hybrid film (NiHCF‐PEDOT) was prepared on a glassy carbon electrode (GCE) by multiple scan cyclic voltammetry. The films were characterized using atomic force microscopy, field emission scanning electron microscopy, energy dispersive spectroscopy, X‐ray diffraction, and electrochemical impedance spectroscopy (AC impedance). The advantages of these films were demonstrated for the detection of ascorbic acid (AA) using cyclic voltammetry and amperometric techniques. The electrocatalytic oxidation of AA at different electrode surfaces, such as the bare GCE, the NiHCF/GCE, and the NiHCF‐PEDOT/GCE modified electrodes, was determined in phosphate buffer solution (pH 7). The AA electrochemical sensor exhibited a linear response from 5×10−6 to 1.5×10−4 M (R2=0.9973) and from 1.55×10−4 to 3×10−4 M (R2=0.9983), detection limit=1×10−6 M, with a fast response time (3 s) for AA determination. In addition, the NiHCF‐PEDOT/GCE was advantageous in terms of its simple preparation, specificity, stability and reproducibility.
Voltammetry of Aluminum Nanoparticles in Aqueous Media with Hanging Mercury Drop Electrode
Authors: Korshunov Andrey , Heyrovský Michael 
Published: May 2010

AbstractThe method of linear cyclic voltammetry with hanging mercury drop eletctrode allows to follow the behaviour of aluminum nanoparticles in aqueous dispersions. The particles gradually react with the dispersion medium to form aluminum hydroxide over various intermediate aggregates depending on composition of the dispersing solution. Voltammetry shows adsorption at the electrode of some of the reaction intermediates and formation of aluminum amalgam when the bared metallic core contacts the electrode.
Techno‐economics of the production of mixed alcohols from lignocellulosic biomass via high‐temperature gasification
Authors: Dutta Abhijit , Bain Richard L. , Biddy Mary J. 
Published: May 2010

AbstractThis techno‐economic study investigates the production of mixed alcohols from lignocellulosic biomass using an entrained flow slagging gasifier. Similar analyses for 2000 dry tonne per day plants have been performed at the National Renewable Energy Laboratory using indirect, and direct dry ash gasifiers. The use of a high‐temperature entrained flow gasifier differs from the previous studies because it eliminates equipment for tar and methane reformation. The conversion targets for tar reforming in the previous studies, and for alcohol synthesis in all of the studies, are based on DOE's research goals for 2012. The conversion cost increased compared to both of the previous studies, assuming the achievement of the 2012 research targets. Feed handling, high oxygen demand, and a high gasifier capital cost are primarily responsible for the high cost projected by this study. It is understood that the achievement of research targets, maturity, reliability, relative complexities, and redundancy requirements will be the other keys to commercialization. The effect of key assumptions and uncertainties were evaluated using sensitivity analysis. © 2010 American Institute of Chemical Engineers Environ Prog, 2010
Detailed kinetic modeling to predict syngas composition from biomass gasification in a PBFB reactor
Authors: Evans Paul , Paskach Thomas , Reardon John 
Published: May 2010

AbstractA method is presented for predicting syngas composition from a pressurized bubbling fluidized bed (PBFB) gasifier. Cantera is used to perform 1D kinetic calculations based on detailed kinetic mechanisms of combustion. Empirical data from a 5‐TPD pilot scale biomass gasifier operating at 1.2 and 4.4 bar are compared with the model calculated results. Multiple kinetic models are compared including: MIT's soot model, Gas Research Institute's GRI 3.0 mechanism, Lawrence Livermore National Laboratory's (LLNL) Cyclohexane model, LLNL's Reduced Heptane mechanism, and Creck Modelling's Biomass 0810 mechanism. Reasonable agreement is achieved with the kinetic models and the empirical data. The effects of various operating parameters on product yields, heat loss, and thermal efficiency in a 30‐cm inner diameter gasifier are studied. Results indicate that product gas heating value and chemical energy efficiency are both improved with elevated pressure operation. © 2010 American Institute of Chemical Engineers Environ Prog, 2010
Comparing chloride and water isotopes as hydrological tracers in two Scottish catchments
Authors: Kirchner James W. , Tetzlaff Doerthe , Soulsby Chris 
Published: May 2010

AbstractTime series of chloride concentrations and oxygen‐18 isotopic ratios are widely used for tracing catchment storage and mixing processes and for inferring catchment travel‐time distributions. However, neither chloride nor oxygen‐18 is an ideal hydrologic tracer: chloride concentrations in streamwater can be affected by dry deposition, evapoconcentration and biogeochemical cycling, and water isotopes can be fractionated by evaporation. One way to test the reliability of these tracers is to determine whether, despite artifacts such as these, both tracers lead to similar inferences when measured in the same catchment. Here, we compare chloride and oxygen‐18 time series in the Girnock and Allt' a Mharcaidh catchments in Scotland. Semivariograms and power spectra for both tracers exhibit similar patterns of fluctuation damping, implying that the travel‐time distributions of the two tracers have similar shapes. Fluctuations of both tracers are strongly damped in streamflow compared to precipitation, implying that these catchments integrate tracer signatures over many different storm events. Streamflow fluctuations of both tracers are more strongly damped at the Allt' a Mharcaidh catchment, implying longer storage and greater mixing of waters of different ages, compared to the Girnock catchment. At both sites, streamflow fluctuations of oxygen‐18 are more strongly damped, relative to precipitation, than those of chloride, leading to estimates of mean travel times that are longer, by a factor of 2–3, for oxygen‐18 than for chloride. The greater variability of chloride compared to oxygen‐18 may arise from spatially and temporally varying occult deposition and evapoconcentration. Nonetheless, the similarities in the behaviour of the two tracers imply that the strong tracer damping and long travel times that have been observed in many catchment studies are not artifacts, but instead reflect storage and mixing of waters over long time scales. Copyright © 2010 John Wiley & Sons, Ltd.
Comparison of outcomes based on treatment algorithms for rhabdomyosarcoma of the bladder/prostate: Combined results from the Children's Oncology Group, German Cooperative Soft Tissue Sarcoma Study, Italian Cooperative Group, and International Society of Pediatric Oncology Malignant Mesenchymal Tumors Committee
Authors: Rodeberg David A. , Anderson James R. , Arndt Carola A. , Ferrer Fernando A. , Raney Richard Beverly , Jenney Meriel E. , Brecht Ines B. , Koscielniak Ewa , Carli Modesto , Bisogno Gianni , Oberlin Odile , Rey Annie , Ullrich Fred , Stevens Michael C. G. , Meyer William H. 
Published: May 2010

AbstractThe purpose of this study was to determine patient characteristics and outcomes for bladder/prostate (BP) rhabdomyosarcoma (RMS) using an international cohort of prospectively treated patients comparing different treatment algorithms. Data were collected from 379 patients (1979–1998) treated on protocol; Intergroup Rhabdomyosarcoma Study, IRS‐IV (n = 239 patients), International Society of Pediatric Oncology Malignant Mesenchymal Tumors (MMT) Committee MMT‐84 and ‐89 (n = 74), Italian Cooperative Group, RMS‐79 and RMS‐88 Studies (n = 37) or German Cooperative Soft Tissue Sarcoma Study CWS‐91 protocols (n = 29). A total of 322 (85%) patients had localized embryonal RMS (ERMS) and 27 had metastatic disease. Thirty patients (21 local disease; 9 metastatic) had nonembryonal BP RMS. Patients with localized ERMS had large tumors (64% >5 cm) that were invasive (54%) with uninvolved regional lymph nodes (N0, 93%). The 5‐year failure‐free survival (FFS) was 75% and the overall survival (OS) was 84%, with 89% of deaths attributed to disease. Treatment failures were usually local disease recurrence (60%). Predictors of FFS included T‐stage (invasiveness), size, and histology. FFS was decreased for patients not receiving initial radiotherapy but this did not translate into a decreased OS. The 21 patients with localized nonembryonal BP RMS had a FFS and OS of 47%. The 36 patients with metastatic disease were more likely to be older and had large tumors that were invasive with alveolar histology and regional lymph node involvement. The 5‐year FFS and OS were 41 and 44%, respectively. In conclusion, the majority of BP RMS patients had localized ERMS with a resultant good prognosis using current treatment algorithms. There were differences in FFS between treatment protocols but this did not result in an altered OS.
A distinct role of RhoB in gastric cancer suppression
Authors: Zhou Jitao , Zhu Yajie , Zhang Guoyun , Liu Na , Sun Lijun , Liu Ming , Qiu Meng , Luo Deyun , Tang Qiulin , Liao Zhengyin , Zheng Yi , Bi Feng 
Published: May 2010

AbstractAlthough Rho family GTPases RhoA, RhoB and RhoC share more than 85% amino acid sequence identity, they may play distinct roles in tumor progression. RhoA and RhoC have been suggested to have positive effects on tumor progression, but the role of RhoB in cancer, particularly in gastric cancer, remains unclear. In our study, we have examined the expression levels of these three Rho GTPases in a large panel of specimens from gastric cancer patients by immunohistochemistry. We found that RhoA and RhoC expression were significantly elevated, while RhoB was reduced or absent, in surgically removed gastric cancer tissues when compared to normal gastric tissues. The significant reduction of RhoB expression was confirmed in another group of gastric cancer samples in comparison to the adjacent non‐neoplastic tissues. Then we transfected the plasmids containing RhoA, RhoB or RhoC cDNA into two gastric cancer cell lines, SGC7901 and AGS cells, respectively. By overexpression experiments, we found that RhoA promoted the gastric cancer cell proliferation and RhoC stimulated migration and invasion of the cancer cell. RhoB expression, however, significantly inhibited the proliferation, migration and invasion of the gastric cancer cells and also enhanced the chemosensitivity of these cells to anticancer drugs. It appears that RhoB plays an opposing role from that of RhoA and/or RhoC in gastric cancer cells. Our work suggests that RhoB may play a tumor suppressor role and subsequently may have potential implications in future targeted therapy.
The history of the Australian Society for Biochemistry and Molecular Biology
Authors: Friedman Liana 
Published: May 2010

AbstractThe Australian Biochemical Society was established in 1955 and has played a crucial role in nurturing science in Australia. In 1990, the Society underwent a name change to become the Australian Society for Biochemistry and Molecular Biology (ASBMB). Today, the majority of ASBMB's members (1,000) work in universities and research institutes, although many also come from industry, hospitals, and government agencies. The Society is also strongly supported by its Sustaining Members, which are science‐related companies and other commercial entities. © 2010 IUBMB IUBMB Life 62(7): 486–491, 2010
The treatment of acute liver failure with fractionated plasma separation and adsorption system: Experience in 85 applications
Authors: Şentürk Evren , Esen Figen , Özcan Perihan E. , Rifai Kinan , Pinarbaşi Binnur , Çakar Nahit , Telci Lutfi 
Published: May 2010

AbstractIntroduction: Artificial liver support systems represent a potential useful option for the treatment of liver failure. The outcomes of patients treated with the fractionated plasma separation and adsorption (FPSA) system are presented. Patients and methods: FPSA was performed 85 times for 27 patients (median 3 treatments/patient) with liver failure [85.2% acute liver failure (ALF) and 14.8% acute‐on‐chronic liver failure] using the Prometheus 4008H (Fresenius Medical Care) unit. Citrate was used for anticoagulation. A variety of clinical and biochemical parameters were assessed. Comparisons between pretreatment and post‐treatment data were performed using paired t‐test. Results: The 85 sessions had a mean duration of 6 h. There were significant decreases in total bilirubin (13.18 ± 9.46 mg/dL vs. 9.76 ± 7.05 mg/dL; P < 0.0001), ammonia (167.6 ± 75 mg/dL vs. 120 ± 43.8 mg/dL; P < 0.0001), blood urea nitrogen (BUN; 12.55 ± 13.03 mg/dL vs. 8.18 ± 8.15 mg/dL; P < 0.0001), creatinine (0.54 ± 0.47 mg/dL vs. 0.46 ± 0.37 mg/dL; P = 0.0022) levels, and in pH (7.48 ± 0.05 vs. 7.44 ± 0.08; P = 0.0045). Four patients (14.8%) received liver transplantation after the treatments; in nine patients, transplantation was not necessary anymore (33%); the remaining 14 patients did not receive a transplantation because they were either not appropriate candidates or no organ was available. Overall survival was 48.1% (4 transplanted and 9 treated patients). No hematological complications related to FPSA were observed. Conclusions: FPSA system is a safe and effective detoxification method for patients with liver dysfunction, including ALF. The system is useful as a symptomatic treatment before liver transplantation; in up to 1/3 of the cases, it can even be used as a sole method of treatment. J. Clin. Apheresis 25:195–201, 2010. © 2010 Wiley‐Liss, Inc.
Mode of action of ferric and ferrous iron salts in activated sludge
Authors: Oikonomidis Ioannis , Burrows Laura J. , Carliell‐Marquet Cynthia M. 
Published: May 2010

AbstractBACKGROUND: Both ferric iron Fe(III) and ferrous iron Fe(II) salts are commonly used for chemical phosphorus removal (CPR) in the activated sludge (AS) process but only a few studies have compared Fe(III) and Fe(II) salts regarding their effect on the physical and biological properties of AS. In this research, the units of a continuous flow laboratory‐scale AS plant were dosed with Fe(III) and Fe(II) salts at a concentration of 25 mg Fe dm−3 feed and changes in the AS properties were measured as Fe accumulated or washed out during startup, normal operation and withdrawal of dosing.RESULTS: The morphological characteristics of the flocs showed marked differences depending on the type of ion used. Fe(II) dosed flocs were more compact, less filamentous and smaller in size than Fe(III) dosed flocs. The settleability index of the Fe(II) dosed sludge was lower than that of the Fe(III) dosed sludge. The activity of ammonium (NH4+‐N) and nitrite (NO2−‐N) oxidizing bacteria was found to be affected by the accumulation of Fe relating products into the sludge.CONCLUSIONS: Fe(II) was a more effective flocculent than Fe(III) and this was attributed to its ability to form stronger ionic bonds with the flocs prior to its oxidation to Fe(III). A hypothesis explaining the mode of action of Fe(II) is proposed. Floc surface properties were enhanced, this being beneficial to the morphological characteristics and settleability with further implications for the operation of AS. However, the effect may be reversed at high Fe contents. Copyright © 2010 Society of Chemical Industry