bluuebunny/crossref_metadata_2025 huggingface dataset:
Recrystallization and Grain Growth in Ultrafine‐Grained Materials Produced by High Pressure Torsion
Authors: Khorashadizadeh Anahita , Raabe Dierk , Winning Myrjam , Pippan Reinhard
Published: December 2010

Ultrafine‐grained (UFG) materials processed by severe plastic deformation are known to exhibit good mechanical properties. Much about the annealing behavior of such materials is still unknown, and this work aims to provide a better understanding of the thermal properties of UFG materials. For this purpose a Cu–0.17 wt%Zr alloy was subjected to high pressure torsion (HPT) with a maximal pressure of 4.8 GPa at room temperature. The microstructures of the specimens were characterized using electron back scatter (EBSD) measurements, transmission electron microscopy (TEM), and hardness measurements. During annealing of the samples, dispersoids were formed which improved the thermal stability of the alloy. At higher strain levels the fraction of high angle grain boundaries (HAGBs) increased above 70% of the total grain boundaries.
Production of Ultrafine Grained AlMnFe Samples by Confined Channel Die Pressing as Compared to Equal Channel Angular Pressing
Authors: Berghammer Rolf , Hu Weiping , Hasani Arman , Gottstein Günter
Published: December 2010

Ultrafine grained material was produced by equal channel angular pressing and confined channel die pressing. Microstructure and mechanical properties of the obtained samples were compared. The different effects on microstructure evolution and mechanical properties from both processes are discussed.
In Situ Diffraction Experiments for the Investigation of Phase Fractions and Ordering Temperatures in Ti‐44 at% Al‐(3‐7) at% Mo Alloys
Authors: Schmoelzer Thomas , Mayer Svea , Sailer Christian , Haupt Frank , Güther Volker , Staron Peter , Liss Klaus‐Dieter , Clemens Helmut
Published: December 2010

Being a strong β stabilizer, Mo has gained importance as an alloying element for so‐called β/γ‐TiAl alloys. Intermetallic TiAl‐based alloys which contain a significant volume fraction of the body‐centered cubic β‐phase at elevated temperatures have proven to exhibit good processing characteristics during hot‐working. Unfortunately, the effect of Mo on the appearing phases and their temperature dependence is not well known. In this work, sections of the Ti‐Al‐Mo ternary phase diagram derived from thermodynamic calculations as well as experimental data are presented. The phase transition temperatures stated in these phase diagrams are compared with the results of high‐temperature diffraction studies using high‐energy synchrotron radiation. Additionally, the disordering temperature of the βo‐phase is determined.
Investigation of the Effects of Different Types of Investments on the Alpha‐Case Layer of Ti6Al7Nb Castings
Authors: Altindis Mustafa , Hagemann Katrin , Polaczek Andreas Bührig‐ , Krupp Ulrich
Published: December 2010

The effects of four different types of investment on the alpha‐case layer of Ti6Al7Nb (Ti67) castings are summarized. The formation mechanism of the alpha‐case layer is investigated. Four different investment materials are compared. The alpha‐case layers on castings produced with Invest‐TiT, Al2O3, and ZrSiO4‐based investments comprise an oxide layer, an alloy layer, and a hardening layer, and are not only formed by interstitial oxygen but also by substitutional elements dissolved from mould materials. The Y2O3‐based investment material provides the most‐reliable choice for the production of titanium castings and is beneficial for the casting of Ti67 because of no alpha‐case formation.
Gas dispersion in air‐lift reactors: Contribution of the turbulent part of the added mass force
Authors: Ali Rahmani Mohamed , Jamel Chahed , Ghazi Bellakhal , Line Alain
Published: December 2010

Gas dispersion in an airlift reactor focusing on the closure law on turbulent contribution of added mass is presented. A data bank for bubbly flow in an airlift reactor is presented. The liquid velocity is measured by hot film anemometry and gas fraction and velocity are measured with an optical probe. The sensitivity of numerical simulations of gas dispersion to the modeling of turbulent contribution of added mass is shown. Without the turbulent contribution, the bubbles move toward the region where the turbulence is high and the pressure is low. When the turbulent contribution is introduced, the bubble migration towards the low pressure region is counter‐balanced and the void fraction profile is significantly modified. The modeling of the turbulent contribution of added mass is expressed in terms of the turbulent correlations in the gas phase, uGi′uGj′, that can be related to the Reynolds stress in the liquid phase, ui′uj′. © 2011 American Institute of Chemical Engineers AIChE J, 2011
One‐dimensional single rising bubble at low Reynolds numbers: solution of equation of motion by differential transformation method
Authors: Jalaal M. , Ghafoori S. , Motevalli M. , Nejad M. G. , Ganji D. D.
Published: December 2010

The behavior of ascending bubbles is of fundamental importance for understanding many natural and artificial phenomena. In this study, the unsteady motion of a single spherical air bubble rising in a stationary viscous liquid has been studied for low Reynolds numbers. Bubble rising under the in?uence of gravitational force is one of the most common gas–liquid flow phenomena. Understanding the dynamic interaction between the phases is an important key for the design and operation of industrial applications. A particular instance of this situation occurs in gas–liquid column reactors. The equation of motion included an additional mass term and neglected the Basset term. An exact solution is derived for instantaneous velocity using a series‐based technique, called the differential transformation method (DTM), and the acceleration and position of the bubble were determined. A general solution of the equation was obtained, and also for several practical conditions with air as the gas phase and glycerin solutions of different concentrations as liquid phase. The results obtained demonstrate the effectiveness of using DTM and promote a new application of this powerful analytical tool for solving nonlinear problems in two‐phase flows. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
Study on biodiesel from cotton seed oil by using heterogeneous super acid catalyst SO42−/ZrO2
Authors: Niu Lei , Gao Lijing , Xiao Guomin , Fu Baosong
Published: December 2010

Biodiesel has been drawing a great deal of attention on account of its special environment friendly and fuel properties. However, the cost of biodiesel production is still very high compared with that of traditional fossil fuels. In this study, a heterogeneous super acid catalyst and inedible oil were used to reduce the cost of raw materials. Biodiesel was obtained from cotton seed oil (CSO) and catalyzed by the super acid SO42−/ZrO2, which was prepared by impregnation and characterized by infrared spectroscopy, thermo‐gravimetric analysis (TGA) and X‐ray diffraction (XRD). Different operation parameters of the transesterification of CSO with methanol, such as methanol/oil molar ratio, catalyst amount and loaded mass ratio, reaction time and temperature, were investigated. Under the optimum conditions of methanol to CSO molar ratio of 9:1, 3.5 wt% fresh catalyst (loaded mass ratio is 0.841), 1 h reaction time and reaction temperature of 120 °C, a relatively high biodiesel yield of 98% was obtained. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
One‐pot Synthesis of 5‐{[Bis(azolylmethylthio)]methylene}pyrimidine‐2,4,6‐(1H,3H,5H)‐triones
Authors: Padmavathi Venkatapuram , Reddy Guda Dinneswara , Venkatesh Bhumireddy Chinnachennaiahgari , Padmaja Adivireddy
Published: December 2010

A new class of hitherto unknown trisheterocycles, bisoxadiazolyl/bisthiadiazolyl pyrimidinetriones/thioxopyrimidinediones was prepared in a one‐pot reaction and their antimicrobial activity was studied.
Synthesis, Characterization, Antioxidant and Antitumor Evaluation of Some New Thiazolidine and Thiazolidinone Derivatives
Authors: Gouda Moustafa A. , Abu‐Hashem Ameen A.
Published: December 2010

2‐(2‐Cyano‐acetylamino)‐4,5,6,7‐tetrahydrobenzo[b]thiophene‐3‐carboxylic acid ethyl ester (2) was utilized as a key intermediate for the synthesis of thiocarbamoyl derivative 3 via its reaction with phenyl isothiocyanate. Treatment of 3 with chloroacetyl chloride afforded thiazolidin‐5‐one 4. Compound 7 reacted with different α‐halo carbonyl compounds to give thiazolidine 8a,b, and thiazolidin‐4‐one derivatives 9. Treatment of 4 with the appropriate aromatic aldehyde and tolyl diazonium chloride afforded the corresponding thiazolidin‐5‐one derivatives 5a,b and 6, respectively. The thiazolidin‐4‐one derivative 10 was obtained via the reaction of compound 2 with 2‐mercaptoacetic acid. Finally, the thiazoline 11 was obtained via the reaction of compound 2 with phenyl isothiocyanate/sulfur. The title compounds were characterized by elemental analyses and spectral data. The quantum mechanical calculations for some compounds were accomplished and subjected for antioxidant and antitumor studies, whereas, some of them exhibited promising activities.
Self‐Assembly of 3,6‐Bis(4‐triazolyl)pyridazine Ligands with Copper(I) and Silver(I) Ions: Time‐Dependant 2D‐NOESY and Ultracentrifuge Measurements
Authors: Happ Bobby , Pavlov Georges M. , Altuntas Esra , Friebe Christian , Hager Martin D. , Winter Andreas , Görls Helmar , Günther Wolfgang , Schubert Ulrich S.
Published: December 2010

Two 3,6‐bis(R‐1H‐1,2,3‐triazol‐4‐yl)pyridazines (R=mesityl, monodisperse (CH2CH2O)12CH3) were synthesized by the copper(I)‐catalyzed azide–alkyne cycloaddition and self‐assembled with tetrakis(acetonitrile)copper(I) hexafluorophosphate and silver(I) hexafluoroantimonate in dichloromethane. The obtained copper(I) complexes were characterized in detail by time‐dependent 1D [1H, 13C] and 2D [1H‐NOESY] NMR spectroscopy, elemental analysis, high‐resolution ESI‐TOF mass spectrometry, and analytical ultracentrifugation. The latter characterization methods, as well as the comparison to analog 3,6‐di(2‐pyridyl)pyridazine (dppn) systems and their corresponding copper(I) and silver(I) complexes indicated that the herein described 3,6‐bis(1H‐1,2,3‐triazol‐4‐yl)pyridazine ligands form [2×2] supramolecular grids. However, in the case of the 3,6‐bis(1‐mesityl‐1H‐1,2,3‐triazol‐4‐yl)pyridazine ligand, the resultant red‐colored copper(I) complex turned out to be metastable in an acetone solution. This behavior in solution was studied by NMR spectroscopy, and it led to the conclusion that the copper(I) complex transforms irreversibly into at least one different metal complex species.
Protein‐protein interactions: Making sense of networks via graph‐theoretic modeling
Authors: Pržulj Nataša
Published: December 2010

The emerging area of network biology is seeking to provide insights into organizational principles of life. However, despite significant collaborative efforts, there is still typically a weak link between biological and computational scientists and a lack of understanding of the research issues across the disciplines. This results in the use of simple computational techniques of limited potential that are incapable of explaining these complex data. Hence, the danger is that the community might begin to view the topological properties of network data as mere statistics, rather than rich sources of biological information. A further danger is that such views might result in the imposition of scientific doctrines, such as scale‐free‐centric (on the modeling side) and genome‐centric (on the biological side) opinions onto this area. Here, we take a graph‐theoretic perspective on protein‐protein interaction networks and present a high‐level overview of the area, commenting on possible challenges ahead.
Bovine lactoperoxidase – a versatile one‐ and two‐electron catalyst of high structural and thermal stability
Authors: Banerjee Srijib , Furtmüller Paul G. , Obinger Christian
Published: December 2010

Lactoperoxidase (LPO), a member of the peroxidase‐cyclooxygenase superfamily, is found in multiple human exocrine secretions and acts as a first line of defense against invading microorganisms by production of antimicrobial oxidants. Because of its ability to efficiently catalyze one‐ and two‐electron oxidation reactions of inorganic and organic compounds, the heme peroxidase is widely used in food biotechnology, cosmetic industry, and diagnostic kits. In order to probe its structural integrity, conformational, and thermal stability, we have undertaken a comprehensive investigation by using complementary biophysical techniques including UV–Vis, circular dichroism and fluorescence spectroscopy as well as differential scanning calorimetry (DSC). The oxidoreductase exhibits a high chemical and thermal stability under oxidizing conditions but is significantly destabilized by addition of DTT. Due to its unique ester bonds between the prosthetic group and the protein as well as six intra‐chain disulfides, unfolding of the central compact (‐helical core occurs concomitantly with denaturation of the heme cavity. The corresponding enthalpic and entropic contributions to the free enthalpy of unfolding are presented. Together with spectroscopic data they will be discussed with respect to the known structure of bovine LPO and homologous myeloperoxidase as well as to its practical application.
Identification of a Napsamycin Biosynthesis Gene Cluster by Genome Mining
Authors: Kaysser Leonard , Tang Xiaoyu , Wemakor Emmanuel , Sedding Katharina , Hennig Susanne , Siebenberg Stefanie , Gust Bertolt
Published: December 2010

Napsamycins are potent inhibitors of bacterial translocase I, an essential enzyme in peptidoglycan biosynthesis, and are classified as uridylpeptide antibiotics. They comprise an N‐methyl diaminobutyric acid, an ureido group, a methionine and two non‐proteinogenic aromatic amino acid residues in a peptide backbone that is linked to a 5′‐amino‐3′‐deoxyuridine by an unusual enamide bond. The napsamycin gene cluster was identified in Streptomyces sp. DSM5940 by using PCR probes from a putative uridylpeptide biosynthetic cluster found in S. roseosporus NRRL15998 by genome mining. Annotation revealed 29 hypothetical genes encoding for resistance, regulation and biosynthesis of the napsamycins. Analysis of the gene cluster indicated that the peptide core structure is assembled by a nonlinear non‐ribosomal peptide synthetase (NRPS)‐like mechanism that involves several discrete single or didomain proteins. Some genes could be assigned, for example, to the synthesis of the N‐methyl diaminobutyric acid, to the generation of m‐tyrosine and to the reduction of the uracil moiety. The heterologous expression of the gene cluster in Streptomyces coelicolor M1154 resulted in the production of napsamycins and mureidomycins as demonstrated by LC‐ESI‐MS and MS/MS analysis. The napsamycin gene cluster provides a molecular basis for the detailed study of the biosynthesis of this class of structurally unusual compounds.
An Insight into Artificial Leaves for Sustainable Energy Inspired by Natural Photosynthesis
Authors: Zhou Han , Fan Tongxiang , Zhang Di
Published: December 2010

The development of green sustainable energy to control our carbon‐based energy “addiction” and to reduce atmospheric CO2 emissions is one of the most urgent issues regarding the continued existence of man on planet earth. Among renewable energy resources, solar energy is by far the largest exploitable resource. Photosynthesis provides a blueprint for solar energy conversion and storage in fuels. Natural green leaves capture and convert solar energy into chemical fuel through photosynthesis. The two reactions are the splitting of water into hydrogen and oxygen (water splitting) and the reduction of CO2 into carbohydrates (CO2 reduction). Inspired by natural leaves, constructing artificial leaves by mimicking photosynthesis to capture solar energy, split water into hydrogen and oxygen, and convert atmospheric carbon dioxide, thus producing various forms of environmentally clean fuels, is of high significance. Many major advances in this research area are highlighted in this Minireview. Some typical successful prototypes from natural systems that can be used for the biomimetic design of artificial leaves are particularly emphasized.
Gram‐Scale Synthesis of Magnetically Separable and Recyclable Co@SiO2 Yolk‐Shell Nanocatalysts for Phenoxycarbonylation Reactions
Authors: Park Ji Chan , Lee Hyun Ju , Jung Hyun Seok , Kim Mijong , Kim Hae Jin , Park Kang Hyun , Song Hyunjoon
Published: December 2010

Co@SiO2 yolk‐shell nanostructures were fabricated on a gram scale by simple hydrogen reduction of CoO@SiO2 core‐shell nanoparticles without using an etching step. The cobalt core diameters were reduced by the lattice volume contraction of CoO to Co, forming vacancy between the cores and the silica shells. The Co@SiO2 yolk‐shell nanocatalysts were employed for the phenoxycarbonylation of iodobenzene, and exhibited high activity and reusability. The magnetic property of the cobalt cores enabled the facile separation of catalysts from the products.
Effective Decolorization of Azo Dye Utilizing SnO2/CuO/Polymer Films under Simulated Solar Light Irradiation
Authors: Jiang R. , Zhu H.‐Y. , Guan Y.‐J. , Fu Y.‐Q. , Xiao L. , Yuan Q.‐Q. , Jiang S.‐T.
Published: December 2010

SnO2/CuO/polymer flexible thin films were prepared by a solution casting technology and characterized by high‐resolution TEM and XRD. The influences of key operational parameters on photocatalytic decolorization of azo dye (Biebrich Scarlet Red, BSR) were investigated systematically. The results showed good crystalline and clear lattice spacings of the novel composite photocatalyst. BSR was bleached effectively and the decolorization efficiency was >98 % in the presence of 1.0 g L–1 photocatalyst under simulated solar light irradiation. The decolorization was more effective in acidic solution with the optimal pH in the range of 4–6. The tested co‐anions in general decreased the decolorization rates by decreasing the adsorption of BSR on the surface of the photocatalyst and reacting with positive hole (h+)/hydroxyl radicals (HO·).
Supercritical CO2 Extraction of Chlorophyll a from Spirulina platensis with a Static Modifier
Authors: Tong Y. , Gao L. , Xiao G. , Pan X.
Published: December 2010

Supercritical CO2 extraction with a static modifier was applied to extract chlorophyll a from Spirulina platensis. The effects of the process were investigated by single‐factor and response surface analysis experiments. The optimal process parameters for supercritical CO2 extraction were determined to be: ethanol/water as the modifier, 40 vol.‐% water content in the modifier, 21.2 mL modifier volume, 1 h static soaking time, 2 h dynamic extraction time, 48.7 MPa extraction pressure, 326.4 K extraction temperature, and 10 g min–1 CO2 flow rate. The optimized chlorophyll a extraction yield was 6.84 mg g–1. A comparison of the experimental results suggested that the yield of chlorophyll a by supercritical CO2 extraction with modifier was higher than that obtained by conventional solvent extraction.
Path modelling by sequential PLS regression
Authors: Næs T. , Tomic O. , Mevik B.‐H. , Martens H.
Published: December 2010

This paper presents a new approach to path modelling, based on a sequential multi‐block modelling in latent variables. The approach is explorative and focused on interpretation. The method breaks with standard traditions of estimating all paths using one single modelling. Instead, one separate model is estimated for each endogenous block. Each separate model is constructed by stepwise use of the standard PLS regression on matrices that are orthogonalised with respect to each other. The advantages of the approach are that it can allow for different dimensionality within each block, it is invariant to relative weighting of the blocks and it is based on simple and standard methodology allowing for simple outlier detection, validation and interpretation. No convergence problems are involved and the method can be used for situations with many more variables than samples. An application based on sensory analysis of wines will be used to illustrate the method. Copyright © 2010 John Wiley & Sons, Ltd.
A chemometrical approach to study interactions between ethynylestradiol and an AhR‐agonist in stickleback (Gasterosteus aculeatus)
Authors: Andersson Carin , Lundstedt‐Enkel Katrin , Katsiadaki Ioanna , Holt William V. , Van Look Katrien J.W. , Örberg Jan
Published: December 2010

Quantifiable responses in fish, such as induction of certain proteins, can be used as indicators of chemical contamination of waterways. In order to evaluate differences in ethoxyresorufin‐O‐deethylase (EROD) induction capacity of the gill and the liver and effects on organs and biomarker proteins, e.g. gill and liver EROD, hepatosomatic index (HSI), nephrosomatic index (NSI), gonadosomatic index (GSI), spiggin, vitellogenin and sperm motility were analysed in male three‐spined sticklebacks (Gasterosteus aculeatus) exposed for 21 days to β‐naphthoflavone (βNF) alone (Exp 1) or in combination with 17α‐ethynylestradiol (EE2) (Exp 2). The sperm motility variables were studied using computer‐assisted sperm analysis (CASA).

Exp 1: Gill EROD activity was significantly induced in fish exposed to ≥1.2 µg/l and hepatic EROD activity in fish exposed to ≥6 µg/l. No significant effect of ßNF on the production of spiggin or vitellogenin or on sperm variables was found.

Exp 2: A significant additative effect of EE2 + βNF was shown for gill EROD. A significant antagonistic effect of the two compounds was found on NSI where an increased EE2 concentration led to an increase in NSI while an increased concentration of βNF led to a decreased NSI. Interestingly, the results showed that exposure to intermediate concentrations of EE2 and ßNF led to a significant increase in the sperm variables. In the aquatic environment mixtures of numerous chemicals with oestrogenic activity are present, so if the capacity to induce gill EROD activity is a general property of oestrogen‐acting chemicals, our findings are important. Copyright © 2010 John Wiley & Sons, Ltd.
Rotary cement kiln coating estimator: Integrated modelling of kiln with shell temperature measurement
Authors: Sadighi Sepehr , Shirvani Mansoor , Ahmad Arshad
Published: December 2010

Coating thickness protection in the burning zone of a rotary cement kiln during operation is important from the viewpoint of the kiln productivity. In this paper, an integrated model is presented to estimate the coating thickness in the burning zone of a rotary cement kiln by using measured process variables and scanned shell temperature. The model can simulate the variations of the system, thus the impact of different process variables and environmental conditions on the coating thickness can be analysed. The presented steady‐state model derived from heat and mass balance equations uses a plug flame model for simulation of gas and/or fuel oil burning. Moreover, the heat transfer value from shell to the outside is improved by a quasi‐dynamic method. Therefore, at first, the model predicts the inside temperature profile along the kiln, then by considering two resistant nodes between temperatures of the inside and outside, the latter measured by shell scanner, it estimates the formed coating thickness in the burning zone. The estimation of the model was studied for three measured data sets taken from a modern commercial cement kiln. The results confirm that the average absolute error for estimating the coating thickness for the cases 1, 2, and 3 are 3.26, 2.82, and 2.21 cm, respectively.
Removal of Ni(II) Using Cation Exchange Resins in Packed Bed Column: Prediction of Breakthrough Curves
Authors: Gomathi Priya Ponnaiah , Ahmed Basha Chiya , Ramamurthi Veerappan
Published: December 2010

Sorptive removal of Ni(II) from electroplating rinse wastewaters by cation exchange resin Dueolite C 20 was investigated at the temperature of 30°C under dynamic conditions in a packed bed. The effects of sorbent bed length 0.1–0.2 m, fixed flow rate 6 dm3 min−1, and the initial rinse water concentration (C0) 53.1 mg L−1 on the sorption characteristics of Dueolite C 20 were investigated at an influent pH of 6.5. More than 94.5% of Ni(II) was removed in the column experiments. The column performance was improved with increasing bed height and decreasing the flow rate. The Thomas, Yoon–Nelson, Clark, and Wolborska models were applied to the experimental data to represent the breakthrough curves and determine the characteristic design parameters of the column. The sorption performance of the Ni(II) ions through columns could be well described by the Thomas, Yoon–Nelson, and Wolborska models at effluent‐to‐influent concentration ratios (C/C0) >0.03 and <0.99. Among the all models, the Clark model showed the least average percentage time deviation. The sorptive capacity of electroplating rinse water using Ni(II) was found to be 45.98 mg g−1.
Occurrence of the Antimicrobials Sulfamethoxazole and Trimethoprim in Hospital Effluent and Study of Their Degradation Products after Electrocoagulation
Authors: Martins Ayrton F. , Mallmann Carlos A. , Arsand Daniel R. , Mayer Francieli Martins , Brenner Carla G. B.
Published: December 2010

In this study, an investigation was carried out into the occurrence of sulfamethoxazole (SMX) and trimethoprim (TMP) in the effluent of the university hospital (HUSM) of the UFSM. The degradation of these antimicrobials by the electrocoagulation (EC) process was also examined, in both the aqueous solution and hospital effluent, and a study was conducted in order to identify the subproducts formed. The experiments were optimized through factorial planning and, also, checked by response surface methodology. The best conditions for EC (achieving 58.0% of chemical oxygen demand (COD) reduction) were obtained by using 13 mA cm−2, 500 mg L−1 of NaCl, and 30 mm of interelectrode distance. The quantification of SMX (27.8 µg L−1) and TMP (6.65 µg L−1) in the hospital effluent, and the identification of the degradation products were carried out through liquid chromatography‐mass spectrometry quadrupole linear and ion trapping with electrospray ionization (LC‐ESI‐MS/MS_QTrap). Removals of 88.0% (degradation only) and 33.0% (adsorption only) were achieved for aqueous solutions of SMX and TMP, respectively, under optimized conditions. In hospital effluent samples, fortified with additions of SMX and TMP, corresponding removals of 16.0% (degradation) and 28.0% (adsorption) were achieved. This suggests that the EC process is efficient in degrading SMX in aqueous solution, although the same was not the case with TMP. The degradation products of SMX were identified (m/z 256.0 and 288.5); however, only the latter is mentioned in the literature. Toxicological aspects were not considered in this study.
Determination of Sulfamethoxazole and Trimethoprim and Their Metabolites in Hospital Effluent
Authors: Brenner Carla G. B. , Mallmann Carlos A. , Arsand Daniel R. , Mayer Francieli M. , Martins Ayrton F.
Published: December 2010

In this work, an analytical methodological study was carried out to determine the antimicrobials sulfamethoxazole and trimethoprim, as well as their metabolites, in hospital effluent. The determinations were conducted by liquid chromatography tandem mass spectrometry using a hybrid triple quadrupole‐linear ion trap mass spectrometer (LC‐QqLIT‐MS). The data acquisition was made in selected reaction monitoring (SRM) mode, in which two SRM transitions were monitored to ensure that the target compounds were accurately identified by the information dependent acquisition (IDA) function. The limits of detection (LOD) and quantification (LOQ) were 0.25 and 0.80 µg L−1 for sulfamethoxazole and 0.15 and 0.50 µg L−1 for trimethoprim. The linear range for the SMX was 0.8–100.0 µg L−1 and TMP was 0.5–100.0 µg L−1 on the basis of six‐point calibration curves generated by means of linear regression analysis. The coefficients of the correlation were higher than 0.999, which ensured the linearity of the method. The average concentration of sulfamethoxazole and trimethoprim found in hospital effluent was 27.8 and 6.65 µg L−1, respectively. The analytical methodology employed allowed two metabolites to be identified, N4‐acetyl‐sulfamethoxazole and α‐hydroxy‐trimethoprim. Fragmentation pathways were proposed.
Preparation of Magnetic Hydroxyapatite and Their Use as Recyclable Adsorbent for Phenol in Wastewater
Authors: Wang Xianxiang
Published: December 2010

Magnetic hydroxyapatite (HAP), which combined superparamagnetic Fe3O4 nanoparticles and HAP, composite materials were prepared by ultrasound method in this paper. It has also been found that these materials have the ability to adsorb phenol in wastewater. The magnetic materials were investigated by scanning electron microscope, X‐ray diffraction (XRD), Fourier transform infrared spectroscopy, thermal gravimetric analysis, vibrating sample magnetometer, and N2 adsorption in order to elucidate the morphology, structure, and other properties. When the prepared magnetic materials were calcined at 200°C, the prepared Fe3O4 was oxidized to Fe2O3, possessing loose‐shaped holes with a high specific area of 325.2 m2/g, a magnetization intensity of 12.5 emu/g, and the N2 adsorption isotherm belongs to porous adsorption type I. Moreover, the magnetic HAP can adsorb 90% phenol in wastewater. This means that it is an excellent recyclable phenol sorbent for sewage treatment. Experiments confirmed that the Freundlich adsorption isotherms model applies to lower phenol concentrations (0–50 mg/L), while for high phenol concentrations (50–500 mg/L) the Langmuir adsorption isotherms model fits. The magnetic sorbents have the capacity to regenerate after reaching adsorption saturation using ethanol as eluant and external magnetic field as separation unit. The efficiency of adsorption was reduced only by 10% over a six time use period.
Synthesis and Antimicrobial Evaluation of Nitazoxanide‐Based Analogues: Identification of Selective and Broad Spectrum Activity
Authors: Ballard T. Eric , Wang Xia , Olekhnovich Igor , Koerner Taylor , Seymour Craig , Salamoun Joseph , Warthan Michelle , Hoffman Paul S. , Macdonald Timothy L.
Published: December 2010

A library composed of nitazoxanide‐based analogues was synthesized and assayed for increased antibacterial efficacy against the pyruvate–ferredoxin oxidoreductase (PFOR) using microorganisms Helicobacter pylori, Campylobacter jejuni and Clostridium difficile. Derivatives were found to recapitulate and improve activity against these organisms and select analogues were tested for their ability to disrupt the PFOR enzyme directly. The library was also screened for activity against staphylococci and resulted in the identification of analogues capable of inhibiting both staphylococci and all PFOR organisms at low micromolar minimum inhibitory concentrations with low toxicity to human foreskin cells.
Cellular uptake and imaging studies of gadolinium‐loaded single‐walled carbon nanotubes as MRI contrast agents
Authors: Tang Annie M. , Ananta Jeyarama S. , Zhao Hong , Cisneros Brandon T. , Lam Edmund Y. , Wong Stephen T. , Wilson Lon J. , Wong Kelvin K.
Published: December 2010

We quantify here, for the first time, the intracellular uptake (J774A.1 murine macrophage cells) of gadolinium‐loaded ultra‐short single‐walled carbon nanotubes (gadonanotubes or GNTs) in a 3 T MRI scanner usingR2andR2* mappingin vitro. GNT‐labeled cells exhibited high and linear changes in net transverse relaxations (ΔR2and ΔR) with increasing cell concentration. The measured ΔR2* were about three to four times greater than the respective ΔR2for each cell concentration. The intracellular uptake of GNTs was validated with inductively coupled plasma optical emission spectrometry (ICP‐OES), indicating an average cellular uptake of 0.44 ± 0.09 pg Gd per cell or 1.69 × 109Gd3+ions per cell. Cell proliferation MTS assays demonstrated that the cells were effectively labeled, without cytotoxicity, for GNTs concentrations ≤28 µMGd.In vivorelaxometry of a subcutaneously‐injected GNT‐labeled cell pellet in a mouse was also demonstrated at 3 T. Finally, the pronouncedR2* effect of GNT‐labeled cells enabled successfulin vitrovisualization of labeled cells at 9.4 T. Copyright © 2010 John Wiley & Sons, Ltd.
Epidermal growth factor down‐regulates the expression of neutrophil gelatinase‐associated lipocalin (NGAL) through E‐cadherin in pancreatic cancer cells
Authors: Tong Zhimin , Chakraborty Subhankar , Sung Bokyung , Koolwal Pooja , Kaur Sukhwinder , Aggarwal Bharat B. , Mani Sendurai A. , Bresalier Robert S. , Batra Surinder K. , Guha Sushovan
Published: December 2010

BACKGROUND:

The authors previously reported that neutrophil gelatinase‐associated lipocalin (NGAL) overexpression significantly blocked invasion and angiogenesis of pancreatic ductal adenocarcinoma (PDAC). They also demonstrated a loss of NGAL expression in the advanced stages of PDAC. However, little is known regarding the mechanisms of NGAL regulation in PDAC. Because the epidermal growth factor (EGF)‐EGF receptor (EGFR) axis is up‐regulated significantly in PDAC, they examined EGF‐mediated NGAL regulation in these cells.

METHODS:

The NGAL‐positive cell lines AsPC‐1 and BxPC‐3 were used as a model system. Quantitative real‐time polymerase chain reaction (RT‐PCR), Western blot analysis, and immunofluorescence studies were used to investigate EGF‐mediated effects on NGAL expression. E‐cadherin expression was manipulated using lentiviral overexpression or small hairpin RNA constructs. NGAL promoter activity was assessed by luciferase‐reporter assay and electrophoretic mobility shift assay.

RESULTS:

NGAL expression was positively associated with tumor differentiation and was down‐regulated significantly after EGF treatment along with a concomitant reduction of E‐cadherin expression in PDAC cells. E‐cadherin down‐regulation was partly through the EGFR‐dependent mitogen‐activated protein kinase (MEK)/extracellular signal‐regulated kinase (ERK) (MEK‐ERK) signaling pathway. In addition, E‐cadherin down‐regulation reduced NGAL expression in PDAC cells, whereas overexpression of E‐cadherin led to increased NGAL expression and partly rescued the inhibition of NGAL expression by EGF. Furthermore, EGF, in part through E‐cadherin, reduced NGAL promoter activity by blocking nuclear factor κB (NF‐κB) activation.

CONCLUSIONS:

The current study demonstrated for the first time that EGF potently blocked NGAL expression in PDAC cells. This effect was mediated in part through activation of the EGFR‐MEK‐ERK signaling pathway, which, in turn, down‐regulated E‐cadherin with a subsequent reduction in NF‐κB activation. These findings illustrate a novel mechanism by which EGF regulates NGAL expression in PDAC. Cancer 2011;. © 2010 American Cancer Society.
Gas‐Phase Photodissociation of CH3CHBrCOCl at 248 nm: Detection of Molecular Fragments by Time‐Resolved FT‐IR Spectroscopy
Authors: Liu Chia‐Yun , Tsai Ming‐Tsang , Tsai Po‐Yu , Liu Yu‐Ting , Chen Si Ying , Chang Agnes Hsiu Hwa , Lin King‐Chuen
Published: December 2010

By employing time‐resolved Fourier transform infrared emission spectroscopy, the fragments HCl (v=1–3), HBr (v=1), and CO (v=1‐3) are detected in one‐photon dissociation of 2‐bromopropionyl chloride (CH3CHBrCOCl) at 248 nm. Ar gas is added to induce internal conversion and to enhance the fragment yields. The time‐resolved high‐resolution spectra of HCl and CO were analyzed to determine the rovibrational energy deposition of 10.0±0.2 and 7.4±0.6 kcal mol−1, respectively, while the rotational energy in HBr is evaluated to be 0.9±0.1 kcal mol−1. The branching ratio of HCl(v>0)/HBr(v>0) is estimated to be 1:0.53. The bond selectivity of halide formation in the photolysis follows the same trend as the halogen atom elimination. The probability of HCl contribution from a hot Cl reaction with the precursor is negligible according to the measurements of HCl amount by adding an active reagent, Br2, in the system. The HCl elimination channel under Ar addition is verified to be slower by two orders of magnitude than the Cl elimination channel. With the aid of ab initio calculations, the observed fragments are dissociated from the hot ground state CH3CHBrCOCl. A two‐body dissociation channel is favored leading to either HCl+CH3CBrCO or HBr+CH2CHCOCl, in which the CH3CBrCO moiety may further undergo secondary dissociation to release CO.
Extracting Individual Contributions From Their Mixture: A Blind Source Separation Approach
Authors: Dudok de Wit T.
Published: December 2010

Multipoint or multichannel observations in plasmas can frequently be modelled as an instantaneous mixture of contributions (waves, emissions, …) of different origins. Recovering the individual sources from their mixture then becomes one of the key objectives. However, unless the underlying mixing processes are well known, these situations lead to heavily underdetermined problems. Blind source separation aims at disentangling such mixtures with the least possible prior information on the sources and their mixing processes. Several powerful approaches have recently been developed, which can often provide new or deeper insight into the underlying physics.

This tutorial paper briefly discusses some possible applications of blind source separation to the field of plasma physics, in which this concept is still barely known. Two examples are given. The first shows how concurrent processes in the dynamical response of the electron temperature in a tokamak can be separated. The second example deals with solar spectral imaging in the Extreme UV and shows how empirical temperature maps can be built (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The GTPase Rem2 regulates synapse development and dendritic morphology
Authors: Ghiretti Amy E. , Paradis Suzanne
Published: December 2010

Rem2 is a member of the Rad/Rem/Rem2/Gem/Kir subfamily of small Ras‐like GTPases that was identified as an important mediator of synapse development. We performed a comprehensive, loss‐ of‐function analysis of Rem2 function in cultured hippocampal neurons using RNAi to substantially decrease Rem2 protein levels. We found that knockdown of Rem2 decreases the density and maturity of dendritic spines, the primary site of excitatory synapses onto pyramidal neurons in the hippocampus. Knockdown of Rem2 also alters the gross morphology of dendritic arborizations, increasing the number of dendritic branches without altering total neurite length. Thus, Rem2 functions to inhibit dendritic branching and promote the development of dendritic spines and excitatory synapses. Interestingly, binding to the calcium‐binding protein calmodulin is required for the Rem2 regulation of dendritic branching. However, this interaction is completely dispensable for synapse development. Overall, our results suggest that Rem2 regulates dendritic branching and synapse development via distinct and overlapping signal transduction pathways. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 71: 374–389, 2011
Potential impact of drug effects, availability, pharmacokinetics, and screening on estimates of drugs implicated in cases of assault
Authors: Carter Lawrence P.
Published: December 2010

Drug‐facilitated sexual assault (DFSA) is a serious and troubling crime. It is important to know if and how different drugs might be used to facilitate assault in order to deter such crime. There are a number of ways in which drugs that are used for DFSA might not be detected by routine screens. The purpose of this analysis was to draw reasonable inferences regarding drugs with a high likelihood of being used for DFSA and not being detected by routine screens. National data from poison control centres, hospital emergency rooms, and law enforcement seizures were used to evaluate the relative magnitude of problems and illicit availability associated with different classes of drugs. General drug classes were examined to include additional drugs that might be used for DFSA on the basis of their amnesic effects, widespread availability, and pharmacokinetics (i.e. short half‐life). The benzodiazepine‐site ligands zolpidem and eszopiclone, ‘club drugs’ GHB and ketamine, muscle relaxants such as carisoprodol, and antihistamines such as diphenhydramine were identified as drugs that might be used for DFSA and remain undetected by routine screens. Future studies that are designed to examine the role of these drugs in DFSA cases could provide better estimates of their use for DFSA. A better understanding of what is being missed in DFSA cases might help prioritize the development of new assays, provide rationale for the availability of particular assays for routine testing, and inform practitioners and the general public of the potential DFSA risks of certain drugs. Copyright © 2010 John Wiley & Sons, Ltd.
Detection of drugs of abuse by Raman spectroscopy
Authors: West Matthew J. , Went Michael J.
Published: December 2010

Raman spectroscopy can provide rapid, sensitive, non‐destructive analysis of a variety of drug types (e.g. amphetamines, alkaloids, designer drugs, and date rape drugs). This review concentrates on developments in the past 15 years. It considers identification and quantification of drugs of abuse in different types of forensic evidence, including bulk street drugs as well as traces found in drinks, on fibres/clothing, in fingerprints, on fingernails, on bank notes, and in body fluids. Copyright © 2010 John Wiley & Sons, Ltd.
Adulterants in illicit drugs: a review of empirical evidence
Authors: Cole Claire , Jones Lisa , McVeigh Jim , Kicman Andrew , Syed Qutub , Bellis Mark
Published: December 2010

Widespread public perception is that illicit drugs contain substances that are a serious risk to health, even though adulterants are often not considered in clinical or forensic toxicology. This review attempts to present an evidence‐based overview of adulterants in illicit drugs, and their associated toxicity. Adulterants are deliberately added to increase bulk, enhance or mimic a pharmacological effect, or to facilitate drug delivery. Those present unintentionally are as a result of poor manufacturing techniques. From the reports gathered, adulterants are predominantly substances which are readily available, commonly being caffeine, procaine, paracetamol, and sugars. These are likely to have minimal impact on users' health at low dosages. Other adulterants, particularly in injectable drugs, have the potential to cause serious health issues, but the quantities reported, such as strychnine in heroin, are not life‐threatening. The most commonly identified bacterial contaminants identified are Bacillus and Clostridium species. When death or serious illness due to adulteration occurs, circulation of information is particularly vital, such as in the USA regarding heroin and cocaine adulterated with fentanyl, and in Scotland recently regarding anthrax contaminated heroin.

The complex interactions of supply, demand, and control of illicit drugs have a tangible impact on their adulteration. Continuing vigilance and the circulation of information is, therefore, desirable as a public health issue. As part of that strategy, analyses performed for adulterants needs to be encouraged, which are considerably limited in number and scope at the moment. Copyright © 2010 John Wiley & Sons, Ltd.
High sensitive analysis of steroids in doping control using gas chromatography/time‐of‐flight mass‐spectrometry
Authors: Revelsky A. I. , Samokhin A. S. , Virus E. D. , Rodchenkov G. M. , Revelsky I. A.
Published: December 2010

The method of high sensitive gas chromatographic/time‐of‐flight mass‐spectrometric (GC/TOF‐MS) analysis of steroids was developed. Low‐resolution TOF‐MS instrument (with fast spectral acquisition rate) was used. This method is based on the formation of the silyl derivatives of steroids; exchange of the reagent mixture (pyridine and N,O‐bis(trimethylsilyl)trifluoroacetamide (BSTFA)) for tert‐butylmethylether; offline large sample volume injection of this solution based on sorption concentration of the respective derivatives from the vapour‐gas mixture flow formed from the solution and inert gas flows; and entire analytes solvent‐free concentrate transfer into the injector of the gas chromatograph. Detection limits for 100 µl sample solution volume were 0.5–2 pg/µl (depending on the component). Application of TOF‐MS model ‘TruTOF’ (Leco, St Joseph, MO, USA) coupled with gas chromatograph and ChromaTOF software (Leco, St Joseph, MO, USA) allowed extraction of the full mass spectra and resolving coeluted peaks. Due to use of the proposed method (10 µl sample aliquot) and GC/TOF‐MS, two times more steroid‐like compounds were registered in the urine extract in comparison with the injection of 1 µl of the same sample solution. Copyright © 2010 John Wiley & Sons, Ltd.
Characterization, thermal stability studies, and analytical method development of Paromomycin for formulation development
Authors: Khan Wahid , Kumar Neeraj
Published: December 2010

Paromomycin (PM) is an aminoglycoside antibiotic, first isolated in the 1950s, and approved in 2006 for treatment of visceral leishmaniasis. Although isolated six decades back, sufficient information essential for development of pharmaceutical formulation is not available for PM.

The purpose of this paper was to determine thermal stability and development of new analytical method for formulation development of PM. PM was characterized by thermoanalytical (DSC, TGA, and HSM) and by spectroscopic (FTIR) techniques and these techniques were used to establish thermal stability of PM after heating PM at 100, 110, 120, and 130 °C for 24 h. Biological activity of these heated samples was also determined by microbiological assay. Subsequently, a simple, rapid and sensitive RP‐HPLC method for quantitative determination of PM was developed using pre‐column derivatization with 9‐fluorenylmethyl chloroformate. The developed method was applied to estimate PM quantitatively in two parenteral dosage forms.

PM was successfully characterized by various stated techniques. These techniques indicated stability of PM for heating up to 120 °C for 24 h, but when heated at 130 °C, PM is liable to degradation. This degradation is also observed in microbiological assay where PM lost ∼30% of its biological activity when heated at 130 °C for 24 h. New analytical method was developed for PM in the concentration range of 25–200 ng/ml with intra‐day and inter‐day variability of < 2%RSD. Characterization techniques were established and stability of PM was determined successfully. Developed analytical method was found sensitive, accurate, and precise for quantification of PM. Copyright © 2010 John Wiley & Sons, Ltd.
Hemodynamic patterning of the avian atrioventricular valve
Authors: Yalcin Huseyin C. , Shekhar Akshay , McQuinn Tim C. , Butcher Jonathan T.
Published: December 2010

In this study, we develop an innovative approach to rigorously quantify the evolving hemodynamic environment of the atrioventricular (AV) canal of avian embryos. Ultrasound generated velocity profiles were imported into Micro‐Computed Tomography generated anatomically precise cardiac geometries between Hamburger‐Hamilton (HH) stages 17 and 30. Computational fluid dynamic simulations were then conducted and iterated until results mimicked in vivo observations. Blood flow in tubular hearts (HH17) was laminar with parallel streamlines, but strong vortices developed simultaneous with expansion of the cushions and septal walls. For all investigated stages, highest wall shear stresses (WSS) are localized to AV canal valve–forming regions. Peak WSS increased from 19.34 dynes/cm2 at HH17 to 287.18 dynes/cm2 at HH30, but spatiotemporally averaged WSS became 3.62 dynes/cm2 for HH17 to 9.11 dynes/cm2 for HH30. Hemodynamic changes often preceded and correlated with morphological changes. These results establish a quantitative baseline supporting future hemodynamic analyses and interpretations. Developmental Dynamics, 2011. © 2010 Wiley‐Liss, Inc.