bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface complexation modelling of uranyl adsorption onto kaolinite based clay minerals using FITEQL 3.2
Authors: Arda Deniz , Hizal Julide , Apak Resat
Published: January 2007

The aim of this study is to explain how the kaolinite-based clay minerals adsorb hexavalent uranium (uranyl ion), and to model uranyl adsorption based on inner-sphere surface complexation with the kaolinite edge hydroxyl sites and outer-sphere complexation with the permanent charge sites. The adsorption of UO2
2+ on kaolinite-based clay was modeled with the aid of FITEQL 3.2 code using the single-site binding model of the Langmuir approach. Potentiometric titrations and adsorption capacity experiments were carried out in solutions containing different concentrations of the inert electrolyte NaClO4, however adsorption modeling was deliberately done at low ionic strength (0.01 M electrolyte) for enabling adsorption onto the permanent negatively charged sites of kaolinite. When a ‘two-site’ binding model was adopted, i.e., ≡S1OH sites representing silanol and ≡S2OH sites aluminol, a good fit was not obtained, and therefore the involvement of merely aluminol sites in surface complexation was assumed along with the ion exchange-held X2
2-–UO2
2+ species by the NaX permanent charge sites. The uranyl cation was assumed to bind to the clay surface as the sole (unhydrolyzed) UO2
2+ ion and form monodentate surface complexes. The modeling system comprised of surface complexation and ion exchange was resolved with respect to species distributions and relevant stability constants. Electrostatic effects were accounted for using a diffuse layer model (DLM) requiring the minimum number of adjustable parameters. Metal adsorption onto clay showed a steady increase with increasing pH up to pH 5.5, i.e., the edge pH for bulk precipitation at the studied concentration range.
Complex formation of U(VI) with the amino acid L-threonine and the corresponding phosphate ester O-phospho-L-threonine
Authors: Günther A. , Geipel Gerhard , Bernhard Gert
Published: January 2007

The complex formation of uranium(VI) with L-threonine and O-phospho-L-threonine was studied by time-resolved laser-induced fluorescence spectroscopy (TRLFS). An increase in fluorescence emission intensity and a corresponding red shift of the bands in the spectra compared to the free uranyl cation indicate a complex formation between UO2
2+ and the non- and phosphorylated amino acid L-threonine. The complex formation constants for a 1:1 and 1:2 complex in the case of L-threonine were determined to be log β
111=10.33 ± 0.26 at ionic strength I=0.1 M, log β
111=10.25 ± 0.25 and log β
122=19.94 ± 0.24 at ionic strength I=0.5 M. The calculated constants of the different 1:1 uranyl complexes with O-phospho-L-threonine are log β
131=0.28 ± 0.11, log β
121=18.94 ± 0.29 and log β
111=15.02 ± 0.23 at I=0.1 M.
Thermoanalytical (TG-DTA-DTG) investigations of uranium (VI) and thorium (IV) complexes of o-hydroxy N, N
′-dimethylbenzylamine in static air atmosphere
Authors: Khan Samina , Anwar Chaudhary Jamil , Arshad M. , Masud Khalid
Published: January 2007

Differential thermal and thermogravimetric analyses of actinide metal o-hydroxy N,N
′-dimethylbenzylamine complexes of the formulae, [LMO2X2], [LMO2SO4] and [LTh(NO3)4], where M = U, L= o-C6H4OHCH2N(CH3)2 and X = Cl2, NO3
- have been carried out to explore their degradation patterns. The evolved products were identified on the basis of loss in weight on TG coupled with DTA curves. The thermal decomposition of these complexes occurred with the loss of inorganic and organic fragments and exhibited almost similar mode of degradation with minor differences. The composition of the intermediates formed during degradation was confirmed by microanalysis and IR spectroscopy. The residues, after heating above 545°C, corresponded to metal oxides. Degradation mechanisms of these complexes have also been proposed.
Studies on protonation and Th(IV) complexation behaviour of dihydroxybenzenes in aqueous 1 M NaClO4 medium
Authors: Thakur U. K. , Shah Dipti , Sharma R. S. , Sawant R. M. , Ramakumar K. L.
Published: January 2007

Complexing behaviour of three dihydroxybenzenes (DHB) namely, hydroquinone, resorcinol and catechol with Th(IV) along with their protonation constants were studied in 1 M NaClO4 medium at 23 ± 0.5 °C, using pH titration technique. Both protonation and metal-ligand equilibrium constants of dihydroxybenzenes were computed using advance software suite of program HYPERQUAD. Logarithmic values of overall protonation constants (log β1H and log β2H) were found to be 11.47 ± 0.05 and 21.45 ± 0.06, for hydroquinone, 11.76 ± 0.04 and 20.98 ± 0.04 for resorcinol and 12.58 ± 0.03 and 21.87 ± 0.08 for catechol respectively. Complex formation has been investigated in the pH range 2 to 4. The logarithmic values of metal-ligand equilibrium constants obtained in the present work were β13-1=48.51 ± 0.67 and β14-1=64.86 ± 1.25 for hydroquinone, β110=16.98 ± 0.16, β13-1=46.46 ± 0.18 and β14-2=59.65 ± 0.20 for resorcinol and β11-1=14.06 ± 0.10 for catechol. The literature values were reviewed.
Development of [103Pd]-labeled-bis(N
4-methylthiosemicarbazone) complexes as possible therapeutic agents
Authors: Jalilian A. R. , Sadeghi Mahdi , Yari Kamrani Y.
Published: January 2007

Due to interesting tumor seeking properties of bis-thiosemicarbazones, two radio palladium- bis -thiosemicarbazone complexes, i.e., [103Pd]-pyruvaldehyde- bis(N
4-methylthiosemicarbazone) ([103Pd] PTSM) and [103Pd]- di-acetyl-bis (N
4-methylthiosemicarbazone) ([103Pd]ATSM) were prepared according to the analogy of radio copper homologs. Palladium-103 (t
1/2=16.96 d) was produced via the 103Rh(p,n) 103Pd nuclear reaction with proton energy 18 MeV. The final activity was eluted in form of Pd(NH3)2Cl2 in order to react with bis -thiosemicarbazones to yield [103Pd]-labeled compounds. Chemical purity of the product was confirmed to be below the accepted limits by polarography. [103Pd]-labeled bis -thiosemicarbazones were prepared with a radiochemical yield of more than 80% at room temperature after 60–90 min by vortexing a mixture of thiosemicarbazones and Pd activity in ethanol. The purification of the labeled compounds performed by reverse phase column chromatography using C18 plus Sep-Pak. Radiochemical purity of more than 99% specific activity of about 12500–13000 Ci/mol was obtained. The stability of the complexes was checked in final product and presence of human serum at 37 °C up to 48 h. The partition co-efficients of the final complexes were determined. The initial physico-chemical properties of the labeled compounds were compared to those of their copper homologues.
Extraction behavior of rutherfordium into tributylphosphate from hydrochloric acid
Authors: Haba Hiromitsu , Tsukada K. , Asai M. , Toyoshima A. , Ishii Y. , Toume H. , Sato T. , Nishinaka I. , Ichikawa T. , Ichikawa S. , Nagame Yuichi , Sato W. , Matsuo K. , Kitamoto Y. , Tashiro Y. , Shinohara Atsushi , Saito J. , Ito M. , Ikezawa T. , Sakamaki M. , Goto S. , Kudo H. , Kikunaga H. , Arai M. , Kamataki S. , Yokoyama A. , Akiyama K. , Sueki K. , Oura Y. , Schädel M. , Brüchle W. , Kratz Jens Volker
Published: January 2007

The extraction behavior of rutherfordium (Rf) into tributylphosphate (TBP) from hydrochloric acid (HCl) has been studied together with those of the lighter group-4 elements Zr and Hf. The extractability of261Rf,169Hf, and85Zr into TBP was investigated under identical conditions in 7.2–8.0 M HCl by on-line reversed-phase extraction chromatography. The percent extractions of Rf, Hf, and Zr into the TBP resin increase steeply with increasing HCl concentration, and the order of extraction is Zr > Hf ≈ Rf. By considering the order of chloride complexation among these elements, it is suggested that the stability of the TBP complex of Rf tetrachloride is lower than those of Zr and Hf.
Adsorption of U(VI) from dilute aqueous solutions onto peat moss
Authors: Omar H. A. , Aziz M. , Shakir K.
Published: January 2007

The adsorption of U(VI) onto peat moss has been studied as a function of uranium concentration, pH, shaking time and ionic strength. The pH and ionic strength of the solution markedly affect the extent of removal. The attainment of equilibrium is fast and the equilibrium data fit well the Freundlich, Langmuir and Dubinin-Radushkevich equations. A probable mechanism of uptake is discussed. Further studies demonstrate that under optimum conditions peat moss can be used for the treatment of waste solutions containing low concentrations of uranium.
Trace element immobilization by uranyl minerals in granite-hosted uranium ores: Evidences from the Xiazhuang ore field of Guangdong province, China
Authors: Lu Long , Chen Fanrong , Ewing Rodney C. , Wang Rucheng
Published: January 2007

The oxidative alteration of uraninite and the fate of trace elements (Y, LREE, Zr, and Th) in a granite-hosted uranium ore deposit in north Guangdong province, China, were investigated to understand the geochemical behavior of spent UO2fuel and associated fission products and transuranium elements under oxidizing conditions. In light of the paragenetic relationship of the alteration products, two alteration series of uraninite were identified: one is the silicate series with a mineral paragenesis of uraninite → uranyl oxide hydrates → Si-rich uranyl phase → uranophane (Ca[(UO2)(SiO3OH)]2(H2O)5), and the other is the phosphate series with a mineral paragenesis of uraninite → uranyl oxide hydrates → autunite (Ca[(UO2)(PO4)]2(H2O)6) → yingjiangite ((K2,Ca)(UO2)7(PO4)4(OH)6(H2O)6). In contrast to the wide distribution and abundance of uranophane and the uranyl phosphate minerals, uranyl oxides were only occasionally found in the ore samples, suggesting that the uranyl silicates and phosphates should be the predominant alteration products of UO2under oxidizing conditions, although uranyl oxide hydrates would be the solubility-limiting phase of uranium in the very early stage of alteration. Furthermore, the interlayer cation of the uranyl phases in the Xiazhuang uranium ore field is dominated by Ca2+, indicating that the release of uranium and other radionuclides will be limited mainly by uranophane and autunite during the oxidative alteration of spent UO2fuel in underground repositories where enhanced calcium concentration is expected due to cement/water reactions.

Compositionally, the cation atomic ratios in uranyl phases often deviate considerably from their respective stoichiometric values as indicated by the nominal formulae, but the compositional variation does not result in significant structural change as indicated by X-ray diffraction patterns. This observation indicates that the structure of U6+minerals may easily be adjusted to accommodate impurity elements including crystallographically compatible radionuclides. Compared with the primary uraninites, the secondary minerals are slightly enriched in light REE, but significantly depleted in Y3+probably due to its cation-radius mismatch with interlayer Ca2+. The apparent enrichment of Zr4+in uranophane and uranyl phosphates relative to uraninite may result from the coupled substitutions: Zr4+↔ U6+and REE3+↔ Ca2+(K+). Because an adequate charge-balance mechanism and significant distortion of the coordination polyhedra are required for the substitution An4+↔ U6+, this type of substitution may not be common.
Labelling of a monoclonal antibody with 68Ga using three DTPA-based bifunctional ligands and their in vitro evaluation for application in radioimmunotherapy
Authors: Koop Bernd , Reske Sven N. , Neumaier Bernd
Published: January 2007

The most commonly used radiometal for dosimetry in radioimmunotherapy is 111In. This radionuclide has suitable physical properties and its chelation chemistry is similar to that of 90Y, which is frequently used in radiotherapy. Since imaging with a γ-ray emitting radionuclide is less accurate than PET-imaging, we evaluated the labelling of a monoclonal antibody with the β
+-emitter 68Ga and the in vitro stability of the labelled antibody in human serum. We focused our studies on the bifunctional chelators Bn-DTPA, CHX-A′′-DTPA, and mx-DTPA conjugated to the anti-CD45 monoclonal antibody YAML568. The incorporation of 68Ga into the antibody is rapid for all three ligands. After 5 minutes the radiochemical yield is > 95%. The serum stability differs strongly depending on the chelator. The least stable chelate is [68Ga]Bn-DTPA. After 3 h at 37°C in human serum 66% of 68Ga is transchelated from the antibody to transferrin. The [68Ga]CHX-A′′-DTPA chelate is kinetically more stable. 83% of 68Ga were still chelated to the antibody after 4h in human serum. The best results were obtained using mx-DTPA. Only 5% were transchelated from the labelled antibody to transferrin after 4h in human serum. The high in vitro stability and the low transchelation tendency of the [68Ga]mx-DTPA-conjugate enable the accurate determination of antibody biodistribution for dosimetry using PET in combination with conventional [111In]anti-CD45 scintigraphy.
Collection/concentration of trace uranium for spectrophotometric detection using activated carbon and first-derivative spectrophotometry
Authors: El-Sayed A. A. , Hamed Mostafa M. , Hmmad H. A. , El-Reefy S.
Published: January 2007

The need exists for preconcentration of trace and ultratrace amounts of uranium from environmental, geological and biological samples. The adsorption of uranium on various solids is important from the purification, environmental, and radioactivity waste disposal points of view. A method is described for the determination of traces of uranium using first-derivative spectrophotometry after adsorptive preconcentration of uranium on activated carbon. Various parameters that influence the adsorptive preconcentration of uranium on activated carbon, viz., pH, amounts of activated carbon and time of stirring and interference of metals have been studied. First-derivative spectrophotometry in conjunction with adsorptive preconcentration of uranium on activated carbon is used for determining uranium at concentration levels down to 20 ppb (w/v).
Sorption of europium(III) on polymeric silica in perchlorate media
Authors: Pathak P.N. , Choppin Gregory R.
Published: January 2007

Sorption of europium, Eu(III) with polymeric silicic acid has been studied under varying experimental conditions such as pH, ionic strength (I), concentration of silicic acid and of Eu(III), the presence of carbonate ions, and aging time. Sorption studies of Eu(III) at pH 7.50 ± 0.50) andI= 0.20 M NaClO4indicate 1.32 ± 0.06 × 10-5M Eu as the Critical Coagulation Concentration, CCC. Sorption of Eu(III) on colloidal silica increases with increased ionic strength from 80% (0.20 M NaClO4) to 93% (0.89 M NaClO4). The coagulation process is favored by an increase in silica concentration. The influence of CO32-(1.00 × 10-3M) on the reaction of Eu(III) with polysilicic acid was negligible in the pH range 7.0 to 9.0. Dissolved Eu3+binds more strongly to the silicate polymers than do Cs+and Cu2+.
A hydrochemical and isotopic case study around a near surface radioactive waste disposal
Authors: Szántó Zs. , Svingor É. , Futó I. , Palcsu L. , Molnár M. , Rinyu L.
Published: January 2007

As part of the site characterisation program for the near surface radioactive waste treatment and disposal facility (RWTDF) at Püspökszilágy, Hungary, water quality and environmental isotope investigations have been carried out. Water samples for major ion chemistry, tritium, 14C and stable isotope ratio measurements (δ18O, δD, δ34S, δ13C) were taken quarterly from the observation wells, the streams and the precipitation during the period 1999–2001.

The chemical composition of groundwaters presented a continuous transition from waters situated on one side to waters on the top and on the other slope of the disposal suggesting the mixing of the three hydrochemical “endmembers”.

Most of δD and δ 18O data were situated between GMWL and LMWL (δD = 7.2 × δ 18O − 1‰) with Oligocene aquifer presenting recharge of Pleistocene origin and water on the top and the gentle slope of the hill presenting recharge of Holocene origin. δ 34S values of dissolved sulphates varied in a wide range (-14.2‰ to + 5.4‰). The tritium in precipitation varied between 4.4 and 18.1 TU with an annual weighted average of 10 ± 0.3 TU. The streams showed larger fluctuations than the wells, but the changes of δ 18O, δD and T were small compared to those in precipitation (showing seasonal variation). Stable isotope, tritium and radiocarbon data proved that the replenishment of groundwater is slow on the steeper side and the direction of water movement is toward the gentle slope of the hill. It was judged that this path is the one that is most likely to give rise to high doses and, therefore, was used in the hydrological modelling of the safety assessment that followed the present work. The possibility that there may also be transport through the unsaturated zone and systems of perched water tables in layers 1 and 2 to both the Szilágyi and Némedi streams cannot be excluded; the transport along these pathways is likely to be intermittent.
Hydrolysis of plutonium(IV) in acidic solutions: no effect of hydrolysis on absorption-spectra of mononuclear hydroxide complexes
Authors: Walther Clemens , Cho H. R. , Marquardt Christian M. , Neck Volker , Seibert A. , Yun J. I. , Fanghänel Thomas
Published: January 2007

Tetravalent plutonium readily undergoes hydrolysis even in highly acidic aqueous solutions. In the past, many attempts were made to quantify hydrolysis species by means of optical absorption spectroscopy. In the present work solutions ranging from 10−5M to 10-2M (total Pu) concentration in 0.5 M HCl/NaCl (0.3 < pHc< 2.1) are carefully investigated by combining absorption-spectroscopy (UV-Vis, liquid core waveguide capillary) and laser-induced breakdown detection, with special emphasis on the limited solubility of Pu(IV). The results clearly indicate that all changes in the absorption spectra originate from the formation of Pu-polyspecies and colloids. The molar absorptivity of mononuclear Pu(IV) hydroxide complexes does not vary with increasing pHcand ongoing hydrolysis. The normalized absorption spectra of at least the first and the second hydroxide complex (Pu(OH)n4-nn= 1, 2) do not differ from those of the hydrated Pu4+ion.
Bootstrap autoregressive order selection
Authors: Franke Jürgen , Kreiss Jens-Peter , Moser Martin
Published: January 2007

In this paper we deal with the problem of fitting an autoregression of orderpto given data coming from a stationary autoregressive process with infinite order. The paper is mainly concerned with the selection of an appropriate order of the autoregressive model. Based on the so–called final prediction error (FPE) a bootstrap order selection can be proposed, because it turns out that one relevant expression occurring in theFPEis ready for the application of the bootstrap principle. Some asymptotic properties of the bootstrap order selection are proved. To carry through the bootstrap procedure an autoregression with increasing but non–stochastic order is fitted to the given data. The paper is concluded by some simulations.
Parametric and semiparametric inference for shape: the role of the scale functional
Authors: Hallin Marc , Paindaveine Davy
Published: January 2007

We are considering the problem of efficient inference on the shape matrix of an elliptic distribution with unspecified location and either (a) fully specified radial density, (b) radial density specified up to a scale parameter, or (c) completely unspecified radial density. Bickel in [1] has shown that efficiencies under (b) and (c), while being strictly less than under (a), coincide: the efficiency loss caused by an unspecified radial density thus is entirely due to the non-specification of its scale (scale here is not necessarily measured by standard error, as second-order moments may be infinite). Defining scale however requires the choice of a particular scale functional, a choice which has an impact on efficiency bounds. We provide a closed form expression for this efficiency loss, both in hypothesis testing and in point estimation, as a function of the standardized radial density and the scale functional. We show that this loss is maximum at arbitrarily light tails whereas, under arbitrarily heavy tails, it is arbitrarily close to zero: hence, under very heavy tails, ignoring the scale (ignoring the exact density) asymptotically does not harm inference on shape. However, the same loss is nil, irrespective of the standardized radial density, when the scale functional (in dimension k) is the k-th root of the scatter determinant.
Oracle inequalities for multi-fold cross validation
Authors: Vaart Aad W. van der , Dudoit Sandrine , Laan Mark J. van der
Published: January 2007

We consider choosing an estimator or model from a given class by cross validation consisting of holding a nonneglible fraction of the observations out as a test set. We derive bounds that show that the risk of the resulting procedure is (up to a constant) smaller than the risk of an oracle plus an error which typically grows logarithmically with the number of estimators in the class. We extend the results to penalized cross validation in order to control unbounded loss functions. Applications include regression with squared and absolute deviation loss and classification under Tsybakov’s condition.
The cross-validated adaptive epsilon-net estimator
Authors: Laan Mark J. van der , Dudoit Sandrine , Vaart Aad W. van der
Published: January 2007

Suppose that we observe a sample of independent and identically distributed realizations of a random variable, and a parameter of interest can be defined as the minimizer, over a suitably defined parameter set, of the expectation of a (loss) function of a candidate parameter value and the random variable. For example, squared error loss in regression or the negative log-density loss in density estimation. Minimizing the empirical risk (i.e., the empirical mean of the loss function) over the entire parameter set may result in ill-defined or too variable estimators of the parameter of interest. In this article, we propose a cross-validated ε-net estimation method, which uses a collection of submodels and a collection of ε-nets over each submodel. For each submodel sand each resolution level ε, the minimizer of the empirical risk over the corresponding ε-net is a candidate estimator. Next we select from these estimators (i.e. select the pair (s,ε)) by multi-fold cross-validation. We derive a finite sample inequality that shows that the resulting estimator is as good as an oracle estimator that uses the best submodel and resolution level for the unknown true parameter. We also address the implementation of the estimation procedure, and in the context of a linear regression model we present results of a preliminary simulation study comparing the cross-validated ε-net estimator to the cross-validatedL1-penalized least squares estimator (LASSO) and the least angle regression estimator (LARS).
Influence of the addition of Pd and Cu to cobalt catalysts prepared by SMAI for F-T synthesis
Authors: Yu Li-hua , Zhang Shou-min , Guo Xianzhi , Wang Da , Wang Shu-rong , Wu Shi-hua
Published: January 2007

The Co-Pd/SiO2 and Co-Cu/SiO2 catalysts were prepared via solvated metal atom impregnation (SMAI) method and investigated for the Fischer-Tropsch (F-T) synthesis. The catalysts contained 5wt.% Co and a weight ratio of Pd (or Cu) to Co of 1/30. XPS indicated that Co, Pd and Cu were in metallic state. The results of XPS and magnetic measurements showed that Co and Pd (Cu) were alloyed. The Co particles on the catalysts were very highly dispersed and they displayed superparamagnetic behavior. FT-IR indicated that the electrons shifted from Cu and Pd to Co. Catalytic tests showed that CO hydrogenation rates followed the order Pd-Co > Cu-Co > Co.
Interaction of fibrinogen with nanosilica
Authors: Rugal Anna , Gun’ko Vladimir , Barvinchenko Valentina , Turov Vladimir , Semeshkina Tatyana , Zarko Vladimir
Published: January 2007

Interaction of human plasma fibrinogen (HPF) with fumed nanosilica A-300 in a phosphate buffer solution (PBS) was studied using 1H NMR spectroscopy with layer-by-layer freezing-out of bulk and interfacial water in the temperature range of 210–273 K, TSDC (90 T FTIR, and UV spectroscopy methods. An increase in concentration of HPF in the PBS leads to a decrease in amounts of structured water (frozen at T FTIR and UV spectra show that the HPF adsorption on silica leads to structural changes of the protein molecules. These changes and formation of hybrid HPF/A-300 aggregates can increase the rate of clotting that is of importance on nanosilica application as a component of tourniquet preparations.
Characterization of superparamagnetic MgxZn1−x Fe2O4 powders
Authors: Kassabova-Zhetcheva Violeta , Pavlova Lilyana , Samuneva Bisserka , Cherkezova-Zheleva Zara , Mitov Ivan , Mikhov Mikhail
Published: January 2007

Structural and magnetic properties of Mgx Zn1−x Fe2O4 powders have been studied with respect to the application for thermal cancer therapy (magnetic hyperthermia). Mgx Zn1−x Fe2O4 (x=0.1–0.5) powders with particle sizes between 5 and 8 nm were produced by citrate method. The X-ray diffraction patterns of the samples correspond to a spinel phase. The lattice constant and the volume of the elementary cell increase when x changes from 0.1 to 0.5. The FTIR-spectra ascertain the spinel phase formation. The Mossbauer studies reveal the presence of extremely small particles, which undergo superparamagnetic relaxation at room temperature. The core-shell model has been applied to explain quadruple doublets. The quadruple splitting at “shells” is bigger than those at “cores” whereas the isomer shifts remain close. Magnetic studies confirm the presence of extremely small particles that behave as superparamagnetic ones.
Removal of chlorinated solvents from carbonate-buffered water by zero-valent iron
Authors: Jiricek Marek , Sracek Ondra , Janda Vaclav
Published: January 2007

The performance of a ground level reactive cell, filled with Fe0, designed for the treatment of water contaminated by chlorinated solvents, having a total input concentration of approximately 2 mg 1−1 of the principal contaminants trichloroethene and perchloroethene, was tested at the Milovice site in the Czech Republic. A residence time of 1.62 days in the box was sufficient to reduce concentrations to a fraction less than 0.015 of the initial concentration. However, incomplete degradation of cis-1,2-DCE was observed. Reactions approximated first-order kinetics. The principal changes of concentrations of inorganic dissolved species in the reactive cell occurred for Ca2+, HCO 3−, NO 3− (decreased) and for Fe (initially increased, then decreased). Changes for Ca2+ and HCO 3− were caused by the precipitation of secondary carbonate mineral phases such as aragonite and siderite with the minor presence of green rust-CO3. Concentration changes were gradual, along the complete length of the cell with a maximum at the inlet zone. The observations were attributed to minor increases of pH and slow kinetics of precipitation in the carbonate-buffered system. The average porosity loss was estimated to be approximately 2.7 % of the initial porosity per year, suggesting the long-term function of the permeable reactive barrier.
Synthesis and aqueous solution properties of homologous gemini surfactants with different head groups
Authors: Sun Yuhai , Feng Yujun , Dong Hongwei , Chen Zhi , Han Likun
Published: January 2007

A series of homologous gemini surfactants possessing identical hydrophobic chains but different ionic head groups (cationic, anionic, zwitterionic) were synthesized, and their aqueous solution properties were examined. The results showed that the surface activities of gemini surfactants are superior to those of corresponding conventional monomeric surfactants, and molecular arrangements of gemini surfactants at the air-water interface are tighter than those of corresponding conventional surfactants. It was also found that zwitterionic gemini surfactant possesses the highest surface activity among the three surfactants. The behavior at the air-water interface is closely related to the molecular structural features of surfactants, which provide an indication for synthesizing highly-efficient surfactants.
Matrix isolation FTIR spectroscopical study of ethene secondary ozonide
Authors: Bariseviciute Ruta , Ceponkus Justinas , Sablinskas Valdas
Published: January 2007

A new method is used for the separation of ethene secondary ozonide (SOZ) from the other products of ethene ozonization reaction. The reaction was performed in the neat films of the reactants at 77 K. Ethene SOZ was separated from other products of the reaction by vacuum distillation at 190–210 K and analyzed by means of the matrix isolation IR absorption spectroscopy. Spectroscopic data from photolysis of the matrix isolated ozonide was used as an argument for assignment of the infrared spectral bands either to ethene SOZ or to other products of the reaction. The spectra of ethene SOZ isolated in the Ar matrix were analyzed by combining experimental results with the theoretical calculations performed at the MP2 6-311+G (3df, 3pd) level. A new assignment of some experimental fundamental bands is proposed taking in to account the Fermi resonance between CH stretch and the five membered ring vibrations. For the first time more than 30 weak infrared absorption bands were observed and assigned to various combination vibrations and overtones. By using new spectral information concerning the overtones and the combination bands it is concluded that the dissociation of unstable ethene SOZ involving breaking of any of the four CO bonds of the five membered ring of ethene SOZ has low probability. Dissociation of the ring starts from breaking of the OO bond.
Addition of TiO2 nanowires in different polymorphs for dye-sensitized solar cells
Authors: Asagoe Keisuke , Ngamsinlapasathian Supachai , Suzuki Yoshikazu , Yoshikawa Susumu
Published: January 2007

TiO2 (B) and TiO2 anatase nanowires were prepared at 150 °C for 120 h by a hydrothermal method followed by calcination in air at 400 °C for 2 h and at 700 °C for 2 h for TiO2 (B) and TiO2 anatase, respectively. Although dye-sensitized solar cells (DSC) with fully nanowire electrodes showed a rather low light-to-electricity conversion efficiency of 1.33 % for TiO2 (B) and 2.42% for TiO2 anatase, 10 wt % nanowire-dispersed electrodes in a P-25 TiO2-nanoparticle matrix demonstrated improved efficiency of 6.17 % for TiO2 (B) and 6.53% for TiO2 anatase, these exceeding that of pure P-25 electrodes in this work (η=5.59%). The dominant mechanisms of the improvement at 10 wt% for the two different polymorphs are thought to be different, i.e., a light-scattering and film-thickness increment for the TiO2 (B) system, whereas there is an improved conduction path through the matrix for the TiO2 anatase system.
Uncertainty of nitrate and sulphate measured by ion chromatography in wastewater samples
Authors: Tepuš Brigita , Simonič Marjana
Published: January 2007

This paper presents an evaluation of measurement uncertainty regarding the results of anion (nitrate and sulphate) concentrations in wastewater. Anions were determined by ion chromatography (EN ISO 10304-2, 1996). The major sources of uncertainty regarding the measurements’ results were identified as contributions to linear least — square or weighted regression lines, precision, trueness, storage conditions, and sampling. Determination of anions in wastewater is very important for the purification procedure, especially the amount of nitrate in waste and potable waters. The determined expanded uncertainty was 6.1 % for nitrate anions and 8.3 % for sulphate anions. The difference between measurement uncertainties determined by the two methods, the weighted and linear least — square methods, is negligible.
Sub-millivolt amplitude potential oscillations observed in the noise of hydrogen evolution on Ag and Cu microelectrodes
Authors: Szenes Ildikó , Mészáros Gábor , Lengyel Béla
Published: January 2007

A strange effect was observed while using the method of quasi-simultaneous determination of electrochemical voltage noise and impedance to obtain information on the kinetics of the hydrogen evolution reaction on Ag and Cu microelectrodes. Beyond a certain polarizing current density we found microvolt-amplitude potential oscillations on both electrodes with a frequency in the 5 Hz–5 kHz range. The oscillations were observed in every single experiment with Ag and Cu, while no oscillatory behavior was observed during the control experiments with the Pt microelectrode. The presence of the oscillations indicates that the mechanism of hydrogen evolution is more complex compared to the original assumption.
Synthesis and magnetic properties of octahedral ferrite NiχCo1−χ
Fe2O4 nanocrystals
Authors: Kasapoglu Nermin , Birsöz Bahar , Baykal Abdülhadi , Köseoglu Yüksel , Toprak Muhammet
Published: January 2007

A series of Ni doped cobalt ferrite compounds with the formula Niχ Co1−χ Fe2O4 where x=0, 0.2, 0.4, 0.6, 0.8, and 1.0 were prepared using a hydrothermal method and subsequently sintered/annealed at 600 °C for 3 h. The influence of the Ni content on the lattice parameter, a, stretching vibration and the magnetization of specimens were subsequently studied. XRD and FTIR were used to investigate structure and composition variations. All samples were found to have a cubic spinel structure. SEM was used to study morphological variations. The results indicate that the average particle sizes are between 30–35 nm with a narrow size distribution along with nanocrystals forming of regular octahedrons. A decrease in the peak to peak line width and increase in resonance field with increasing Ni content were observed from ESR measurements. Based on ESR results, a core-shell type of formation was proposed where the core is made up of undoped CoFe2O4 and the shell is Ni2+ doped CoFe2O4.
Synthesis, characterization and magnetic investigation of (NH4)0.5Mn1.25(H2O)2[BP2O8]·0.5H2O
Authors: Birsöz B. , Baykal A. , Toprak M. , Köseoglu Y.
Published: January 2007

A new borophosphate compound with the composition (NH4)χ Mn((3−χ)/2)(H2O)2 [BP2O8]·(1−x)H2O was prepared under mild hydrothermal conditions and characterized by X-ray powder diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) methods. The title compound was synthesized from MnCl2·2H2O, H3BO3, and (NH4)2HPO4 with variable molar ratios by heating at 180 °C for 7 days in an autoclave. The X-ray diffraction data of the water insoluble polycrystalline powder was indexed using the TREOR program in hexagonal system with the unit cell parameters of a = 9.5104, c = 15.7108 Å, Z = 6 and the space group P65 (No.176). (NH4)χ Mn((3−χ)/2)(H2O)2 [BP2O8]·(1−x)H2O is isostructural with (NH4)χ M ((3−χ)2)/II (H2O)2 [BP2O8]·(1−x)H2O (MII = Co, Cd, Mg; x = 0.5–1). Its unit cell parameters and hkl values were in good agreement with the other isostructural compounds. This is the first report presenting both the synthetic details and the indexed X-ray powder diffraction pattern of this compound along with the characterization by FTIR, thermal gravimetric analysis, scanning electron microscopy and EPR.
Syringoplutarchusia nordmanni, a new genus and species of the feather mite family Syringobiidae (Acari, Astigmata, Pterolichoidea) from the Black-winged Pratincole Glareola nordmanni (Charadriiformes, Glareolidae)
Authors: Dabert Jacek , Skoracki Maciej
Published: January 2007

Syringoplutarchusia, a new genus of the syringicolous feather mite family Syringobiidae (Pterolichoidea), is described based on a single new species, S. nordmanni sp. nov., collected from the feather quills of a museum specimen of the Black-winged Pratincole Glareola nordmanni Fischer, 1842 (Glareolidae). Absence of adanal discs and complete reduction of setae d and e on tarsi IV in males of the new genus is unique in this family. The highly elongated body shape of both sexes is most similar to the genera Plutarchusia Oudemans, 1904 and Paidoplutarchusia Dabert, 2003 but strong sclerotization of coxal fields and hypertrophied posterior legs with variously shaped apophyses resemble more advanced syringobiid mites, e.g. Syringobia Trouessart et Neumann, 1888. Syringoplutarchusia represents the first syringobiid from this host family. The taxonomic status of the new taxon is discussed.
Initiating Biosafety Procedures in Nepal
Authors: Editor The
Published: January 2007

No abstract available.

Banko Janakari Vol.15(2) 2005 pp1-2.
Assessment of fodder yield from Artocarpus lakoocha and Bauhinia purpurea) tree planting in community forests in the western midhills of Nepal
Authors: Baral S.K. , Shakya R.
Published: January 2007

This experiment assessed the yield and growth performance of the fodder tree planting in the community forest focusing on Artocarpus lakoocha, Bahunia purpurea. Major variables analyzing the yield and growth of the species such as dbh, height, green weight of the foliage was measured. After analyzing the data, Artocarpus lakoocha was found to be good yielding and growth performing species as compared to Bahunia purpurea. Preliminary result shows that yield of the both the species is significantly correlated with dbh and height.

Key words: Artocarpus lakoocha, Bahunia purpurea, fodder, plantation, community forest, yield

Banko Janakari Vol.15(2) 2005 pp3-5
Ethnoecology of natural environment in trans-himalayan region of west Nepal
Authors: Rokaya M.B. , Shrestha M.R. , Ghimire S.K.
Published: January 2007

The present study was conducted during a period of two years from 2001 to 2003 in trans-Himalayan region from Mustang to Dolpa region of west Nepal. The indigenous people were found to be rich in ethnoecological knowledge regarding environment and plant resources. The locals catagorised six types of ecological land patterns such as Nakri (forest land), Penhri or pangri or Thakri or dakri (land pattern), Sim (marshy place or wetland), Lung (agricultural land) and Khangri (Snowy land). The people also had the knowledge of plants in population level and species level and had their own way of classifying them on the basis of different criteria like presence or absence of flower, habit, habitat, morphology, etc.

Key Words: Ethnobotany; Indigenous knowledge; Folk nomenclature; Folk classification

Banko Janakari Vol.15(2) 2005 pp13-18
Monitoring growth of Uttis (Alnus nepalensis) at a plantation cite at Dhankuta, Nepal
Authors: Barakoti T. P.
Published: January 2007

A long-term growth monitoring experiment on Uttis (Alnus nepalensis) was conducted in the permanent sample plots of the Agricultural Research Station (ARS) Pakhribas, Dhankuta for 10 years (1992-2001). The average annual increment was diameter at breast height 2.14 cm in 8th year, and was 0.13 cm at 16th year of planting. The trees grew 44 cm to 130 cm per year irrespective of the age. The highest growth rate correspondend with higher rainfall during summer (March-April). Estimated biomass of stem and branches increased by 2-2.5 times within the 10 years period. Thinning and felling every year indicated need for timely management of the plantation to provide better growing environment. The data would be useful for growth modelling and proper management of Uttis plantation in Nepal .

Key words: Nepalese alder vs Uttis, height, diameter, biomass, Pakhribas.

Banko Janakari Vol.15(2) 2005 pp19-23
Lok Vanaki - a recent innovative approach for managing private forestry in Madhya Pradesh, India
Authors: Bhattacharya A.K. , Basnyat Bijendra
Published: January 2007

This paper highlights on Lok Vanaki (private forestry) scheme, an innovative and decentralized approach for managing private forestry of Madhya Pradesh (MP) and examines on policy provisions, implementation status and explore on issues associated with its implementation. This scheme was launched in Madhya Pradesh in April 1999 for promoting multi-tier scientific management of neglected and degrading forests on private holdings. The State Government has taken adequate measures to provide sufficient legal support to the whole initiative. Lok vanaki has not only helped on conservation and development of private forestry but also in socio-economic upliftment of people. It has also contributed in reducing the unemployment rate of the country concept through the charter foresters, who are fully authorized for preparation, implementation and monitoring of the plan. Efforts are underway to make the programme successful through political commitment.

Key words: Private forestry, Forest acts, Management plan, MP, India.

Banko Janakari Vol.15(2) 2005 pp24-27
Folk use of plant resource at Madi valley of Chitwan District, Nepal
Authors: Bishokarma B.K. , Kinsey C.K. , Dangol D.R. , Chaudhary P.
Published: January 2007

The purpose of this study was to compare the use of the forest plant resources and folk nomenclature in the two communities of the Madi valley a Chitwan District. The information was collected during 2001 from 83 households in Chirauli and 57 households in Dhikurbari using semi-structured questionnaires. The folk nomenclature and relative importance of the plant species for medicine, firewood, fodder and timber differ in the two communities were recorded. A total of 128 species were reported in use by both communities, out of which 64 were common to both communities. The plant species used only in Chirauli accounted for 44 and that in Dhikurbari are 20. Tharu community of Chirauli reported higher number of plant species for medicinal, fodder and forage, fuel wood and timber than that of migrated people of Dhikurbari.

Banko Janakari Vol.15(2) 2005 pp28-33
Biomass estimation of Bambusa nutans subspecies cupulata grown at Eastern Terai, Nepal
Authors: Oli B.N. , Kandel C.M.
Published: January 2007

With a view to prepare biomass table of Bambusa nutans subspecies cupulata grown at Belbari, Morang district of Eastern Terai, a total of 150 culms were selected from nintyeight clumps. Measurements of Diameter at 15 cm of the base (D15), vertical height of the culm and green weight of the culm, branches and foliage were taken in the field. The sampled green weight was oven dried in Kathmandu. To estimate the biomass, regression model was developed on the basis of oven dry and green weight. The model used was W = a + b * (D2L). Based on the oven dry weight, the R2 values obtained for culm, branch and foliage components were 90, 82 and 73 per cent respectively. Similarly, R2 values for culm and foliage components on the basis of green weight were 90 and 73 per cent respectively. The R2 values obtained for branch and foliage components were slightly lower as compared to the culm. The validity is to be done before applying this equation to different site conditions.

Key words: Biomass, bamboo, Bambusa nutans subspecies cupulata, Nepal

Banko Janakari Vol.15(2) 2005 pp34-37
Indigenous use of mistletoes in tropical and temperate region of Nepal
Authors: Kunwar R.M. , Adhikari N. , Devkota M.P.
Published: January 2007

Eleven species of mistletoes are widely used by different ethnic groups of Nepal for various purposes. The local people of the present study areas (one each at tropical and temperate region) were found using eight species of mistletoes for food, fodder and medicine. Noticeable use of the mistletoes is for healing bone fractures, dislocation and sprain.

Key words: Indigenous use, mistletoes, Nepal.

Banko Janakari Vol.15(2) 2005 pp38-42
Socio-economic impacts of community based forest enterprises in mid hills of Nepal-Case Study from Dolakha district
Authors: Acharya R.P.
Published: January 2007

This paper endeavors to assess the socio-economic impact of FUG members affiliated with three Community Based Forest Enterprises (CBFEs) in Dolakha district. Important socio-economic variables, especially household income, gender and equity, decision making process, benefit sharing and resource management were analyzed. The study concludes that the CBFEs have created a positive impact on the socio-economic aspects of rural populace.

Key words: Community based forest enterprises, Gender and equity, Benefit sharing, Decision making, Resource management

Banko Janakari Vol.15(2) 2005 pp43-47
Convention on Biological Diversity and access to genetic resources: International regime and our experiences
Authors: Joshi O.
Published: January 2007

Traditional Knowledge, community rights and access to benefit sharing of biological resources are emerging Issues after Convention on Biological Diversity (CBD) entered into force. This paper highlights legal system of access to benefit sharing in CBD and our efforts made so far to protect traditional knowledge by the legal documentation of biological resources and traditional knowledge associated with it. The paper advocates bioprospecting as a forward looking opportunity to convert natural resources into biological capital and highlights role and responsibility of local people to make equitable sharing of the benefits from the resource they conserve and knowledge they hold.

Key words: Access and benefit Sharing, Traditional Knowledge, Bio-prospecting.

Banko Janakari Vol.15(2) 2005 pp48-52
Beliefs, superstitions and taboos associated with bamboos in Nepal and its implications
Authors: Das A.N. , Mitchell C.P.
Published: January 2007

Bamboos are one of the important natural resources of Nepal. Bamboos have multiple uses and are increasingly used as a replacement of timber for construction purposes. Besides that, its use for craftmaking (woven and unwoven) and furniture has also significantly increased in recent years. For many rural households, which includes socially and economically disadvantaged groups; sale of bamboo and its products is an important source of income and sustaining livelihoods. The promotion of bamboo growing in Nepal can help generate income and can be one of the means for reducing poverty in Nepal. However, there are considerable beliefs, superstition, and taboos associated with bamboos in Nepal, many of which have influenced decision making of households towards bamboo growing in Nepal. The findings of the detailed study on taboos, beliefs and superstitions conducted in the Terai and Midhills and its implications on bamboo growing are discussed in this paper.

Banko Janakari Vol.15(2) 2005 pp63-71
Conductive Mesocellular Silica–Carbon Nanocomposite Foams for Immobilization, Direct Electrochemistry, and Biosensing of Proteins
Authors: Wu S. , Ju H. X. , Liu Y.
Published: January 2007

A mesocellular silica–carbon nanocomposite foam (MSCF) is designed for the immobilization and biosensing of proteins. The as‐prepared MSCF has a highly ordered mesostructure, good biocompatibility, favorable conductivity and hydrophilicity, large surface area, and a narrow pore‐size distribution, as verified by transmission electron microscopy (TEM), IR spectroscopy, electrochemical impedance spectroscopy (EIS), nitrogen adsorption–desorption isotherms, pore size distribution plots, and water contact angle measurements. Using glucose oxidase (GOD) as a model, the MSCF is tested for immobilization of redox proteins and the design of electrochemical biosensors. GOD molecules immobilized in the mesopores of the MSCF show direct electrochemistry with a fast electron transfer rate (14.0 ± 1.7 s–1) and good electrochemical performance. Based on a decrease of the electrocatalytic response of the reduced form of GOD to dissolved oxygen, the proposed biosensor exhibits a linear response to glucose concentrations ranging from 50 μM to 5.0 mM with a detection limit of 34 μM at an applied potential of –0.4 V. The biosensor shows good stability and selectivity and is able to exclude interference from ascorbic acid (AA) and uric acid (UA) species that always coexist with glucose in real samples. The nanocomposite foam provides a good matrix for protein immobilization and biosensor preparation.