Retention of Bentonite in Granular Natural Pozzolan: Implications for Water Filtration

Abstract

Slow sand filtration is wide spread as a rural drinking water treatment process in most of the developing countries, and is well known to become effective after a long period of filtration. This study evaluates the efficiency of granular pozzolans from Djoungo and Koutaba (Cameroon), at the beginning of a slow filtration process, using bentonite as a model colloid, under different physicochemical conditions. Experiments were conducted at various pH 5–9 Petrangeli, M. P., Yassin, D. K., Troia, B. and Majone, M. 1999. Adsorption of lead at variable pH onto a natural porous medium: Modelling of batch and column experiments. Environmental Science & Technology, 33: 4457–4464. Farizoglu, B., Nuhoglu, A., Yildiz, E. and Keskinler, B. 2003. The performance of pumice as a filter bed material under rapid filtration conditions. Filtration & Separation, 40: 41–45. Huang, C., Pan, J. R. and Huang, S. 1999. Collision efficiencies of algae and kaolin in depth filter: The effect of surface properties of particles. Water Research, 33: 1278–1286. Zhuang, J., Jin, Y. and Flury, M. 2004. Comparison of Hanford colloids and kaolinite transport in porous Media. Vadose Zone Journal, 3: 395–402. Amirtharajah, A. and Wetstein, D. P. 1980. Initial degradation of effluent quality during filtration. Journal American Water Works Association, 72: 518–524.  , different ionic strengths (10^?4?3 · 10^?2 M KCl) and various flow velocities up to 0.24 mm/s, with a filter grain size of 400–500 µm. The results show that the pH variation 5–9 Petrangeli, M. P., Yassin, D. K., Troia, B. and Majone, M. 1999. Adsorption of lead at variable pH onto a natural porous medium: Modelling of batch and column experiments. Environmental Science & Technology, 33: 4457–4464. Farizoglu, B., Nuhoglu, A., Yildiz, E. and Keskinler, B. 2003. The performance of pumice as a filter bed material under rapid filtration conditions. Filtration & Separation, 40: 41–45. Huang, C., Pan, J. R. and Huang, S. 1999. Collision efficiencies of algae and kaolin in depth filter: The effect of surface properties of particles. Water Research, 33: 1278–1286. Zhuang, J., Jin, Y. and Flury, M. 2004. Comparison of Hanford colloids and kaolinite transport in porous Media. Vadose Zone Journal, 3: 395–402. Amirtharajah, A. and Wetstein, D. P. 1980. Initial degradation of effluent quality during filtration. Journal American Water Works Association, 72: 518–524.   has little influence on the retention of bentonite clay when the ionic strength is less than 10^?2 M KCl; whereas conditioning the grains at 10^?2 M KCl and pH 5 improves the efficiency of retention, increasing flow velocity results in a small decrease in retention efficiency. The three pozzolans tested gave similar retention efficiencies.     

Exploitation of Beach Sand as a Low Cost Sorbent for the Removal of Pb(II) Ions from Aqueous Solutions

Abstract

Beach sand is used to remove traces of Pb(II) ions from aqueous solutions. Effect of shaking speed, amount of sorbent, shaking time, nature and concentration of different electrolytes and deionized water along with buffer of pH 2–10 Apak, R., Guclu, K. and Turgut, M. H. 1998. Modeling of copper(II), cadmium(II), and lead(II) adsorption on red mud. J. Colloid Interface Sci., 203: 122 Ma, Y. Q., Traina, S. J., Logen, T. J. and Rayan, J. A. 1994. Effect of aqueous Al, Cd, Cu, Fe, Ni, and Zn on Pb immobilization by hydroxyapatite. Environ. Sci. Technol., 28: 1219 Zhang, P. and Ryan, J. A. 1998. Formation of pyronorphite in analgesite‐hydroxiapatite suspension under varying pH conditions. Environ. Sci. Technol., 32: 3318 Marcantonio, F., Flower, G., Thien, L. and Ellgaard, E. 1998. Pb isotopes in tree rings chronology of pollution in BayouTrepagnier; Louesiana. Environ. Sci. Technol., 32: 2371 Klaassen, C. D. 2001. Casarett and Doull's Toxicology: the basic science of poisons, 6th Ed. Edited by: Klaassen, C. D. New York: McGraw Hill. Plunkett, E. R. 1987. Handbook of Industrial Toxicology USA: Edward Arnold Publication Co; Inc. Hasany, S. M. 2000. Inorganic ion‐exchangers for the treatment and disposal of industrial effluents. The Nucleus, 37: 187 (and references therein) Hasany, S. M., Ahmed, R. and Chaudhary, M. H. 2003. Investigation of sorption of Hg(II) ions onto coconut husk from aqueous solution using radiotracer technique. Radiochim. Acta., 91: 533 (and reference therein) Hasany, S. M., Saeed, M. M. and Ahmed, M. 2003. Sorption of traces of silver ions onto polyurethane foam from acidic solution. Talanta, 54: 89 (and reference therein)  have been studied. Maximum sorption of Pb(II) ions (>94%) is achieved from 10^?4M HNO₃. Sorption data have been tested using Langmuir, Freundlich, and Dubinin‐Radushkevich (D‐R) sorption isotherms. Thermodynamic parameters such as ΔH, ΔS, and ΔG have been evaluated. Kinetics of sorption is followed by Morris‐ Weber, Reichenberg and Lagergren equations. Influence of diverse ions on the sorption of Pb(II) ions is also investigated.     

Biosorption of Heavy Metals by Powder of Green Coconut Shell

Abstract

Alternative processing methods are being considered more seriously, sorption and/or complexation of dissolved metals based on the chemical activity of biomass, known as biosorption, is the base of the new technology for metal removal and recovery. Different types of biomass (dead and alive) like bacteria, yeast, bark, fungi, agricultural by‐products, coconut shell, marine algae, peat, moss and aquatic mosses have been investigated for biosorption of heavy metals ions. Biosorption of each of the metal ions by coconut shell powder was investigated in this study. The biosorption capacities of coconut shell for cadmium, chromium, and arsenic were studied at different particle sizes (0.044–0.297 mm), initial metal concentration (20– 1000 mg/L), and solution pH values 2–9 Churchill, S. A., Walters, J. V. and Churchill, P. F. 1995. Sorption of heavy metals by prepared bacterial cell surface. J. Environ. Eng., 121(10): 706–711. Kuyucak, N. and Volesky, B. 1988. Biosorbents for recovery of metals from industrial solutions. Biotechnol. Lett., 10(2): 137–142. Espósito, A., Pagnanelli, F., Lodi, A., Solisio, C. and Veglio, F. 2001. Biosorption of heavy metals by Sphaerotilus natans: an equilibrium study at different pH and biomass concentration. Hydrometallurgy, 60: 129–141. Pino, G. A.H. 2005. “Biosorption of heavy metals using powder of green coconut shell”. Brazil: Master's Thesis, Catholic University of Rio de Janeiro. (In Portuguese) Chandra, K., Kamala, C. T., Chary, N. S. and Anjaneyulu, Y. 2003. Removal of heavy metals using a plant biomass with reference to environmental control. International Journal of Mineral Processing, 68: 37–45. Dornellas de Barros, M. A. 2000. Remoção de metais em água utilizando diversos adsorventes. Revista Tecnológica, : 65–72. Ed especial Gaballah, I., Goy, D., Kilbertus, G. and Thauront, J. 1994a. Decontamination of industrial effluents for environment protection and recycling of metals. Resources, Conservation and Recycling, 10: 97–106. Schneider, I., Rubio, J. and Smith, R. 2001. Biosorption of metals onto plant biomass: exchange adsorption or surface precipitation?. International Journal of Mineral Processing, 62: 111–120.   in batch mode, the experimental data obtained for each metal were evaluated and fitted using adsorption models. Also, analyses were made of biomass by SEM‐EDS before and after the biosorption to confirm the presence of metal ions species.     

Monitoring ZnS Precipitation: Estimation,Error Analysis and Experiment Design

Abstract

A mass balance model of total soluble sulfide and free zinc with a second-order reaction term is theoretically able to reconstruct the zinc effluent concentration and the kinetic parameter (k). However, under real conditions this model predicts the zinc effluent concentration four orders of magnitude higher than the measured ones. The applied error analysis, based on linearization of the model followed by first-order variance propagation, showed that the accuracy of several of the input variables (flows and influent concentrations) jeopardized the estimation of the Zn concentration in the effluent, which is a phenomenon expected for every fast reaction with low product concentration. In order to overcome the inaccuracy issue, an “apparent solubility product” as a function of pS (11-20 König , J. ; Keesman , K.J. ; Veeken , A. ; Lens , P.N.L. ( 2006 ) Dynamic Modelling and Process Control of ZnS Precipitation . Separation Science and Technology , 41 ( 6 ): 1025 – 1042 . Dochain , D. ( 2003 ) State and parameter estimation in chemical and biochemical processes: a tutorial . Journal of Process Control , 13 ( 8 ): 801 – 818 . Del Villar , R.G. ; Thibault , J. ; Del Villar , R. ( 1996 ) Development of a softsensor for particle size monitoring . Minerals Engineering , 9 ( 1 ): 55 – 72 . Zamprogna , E. ; Barolo , M. ; Seborg , D.E. ( 2005 ) Optimal selection of soft sensor inputs for batch distillation columns using principal component analysis . Journal of Process Control , 15 ( 1 ): 39 – 52 . de Brauwere , A. ; De Ridder , F. ; Elskens , M. ; Schoukens , J. ; Pintelon , R. ; Baeyens , W. ( 2005 ) Refined parameter and uncertainty estimation when both variables are subject to error. Case study: estimation of Si consumption and regeneration rates in a marine environment . Journal of Marine Systems , 55 ( 3–4 ): 205 – 221 . Vojinovic , Z. (2007) A complementary modelling approach to manage uncertainty of computationally expensive models. Water Science and Technology , 56 (8): 1–9. Luther III , G.W. ; Rickard , D.T. ; Theberge , S.M. ; Olroyd , A. ( 1996 ) Determination of Metal (Bi)Sulfide Stability Constants of Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, and Zn²⁺ by Voltammetric Methods . Environmental Science & Technology , 30 ( 2 ): 671 – 679 . Luther III , G.W. ; Theberge , S.M. ; Rickard , D.T. ( 1999 ) Evidence for aqueous clusters as intermediates during zinc sulfide formation . Geochimica et Cosmochimica Acta , 63 ( 19–20 ): 3159 – 3169 . Yongsiri , C. ; Vollertsen , J. ; Rasmussen , M. ; Hvitved-Jacobsen , T. ( 2004 ) Air-water transfer of hydrogen sulfide:- an approach for application in sewer networks . Water Environment Research , 76 ( 1 ): 81 – 88 . Fischer , H. ; Schulz-Ekloff , G. ; Wöhrle , D. ( 1997 ) Oxidation of aqueous sulfide solutions by dioxygen. Part 1: Autoxidation reaction . Chemical Engineering & Technology , 20 ( 7 ): 462 – 468 . ) was calculated from the experimental data, allowing for the subsequent determination of an “apparent kinetic parameter” (k _A ), that excluding parallel reactions was between 1.7 × 10²³ – 6.2 × 10²⁴ L/(mol·h). This allowed for further tuning of the model such that the estimates of the Zn effluent concentration became of the same order of magnitude as the measured ones (10^?7 M Zn).     

Effect of Curing Pressure on the Strength of Adhesively Bonded Joints

It is important to be able to predict the mechanical response of adhesively bonded joints. To succeed in this, the accurate simulation of the behavior of adhesively bonded joints is an essential requirement because of the strain rate, temperature, and hydrostatic sensitivity of adhesive properties, which should be taken into consideration when developing a material model [1-11 Dean , G. D. and Crocker , L. E. , Comparison of the Measured and Predicted Deformation of an Adhesively Bonded Lap-Joint Specimen, NPL CMMT(A) 293 ( National Physical Laboratory , Teddington , UK , 2000 ). Read , B. E. , Dean , G. D. , and Ferriss , D. H. , An Elastic–Plastic Model for the Non-linear Mechanical Behaviour of Rubber-Toughened Adhesives, NPL CMMT(A) 289 ( National Physical Laboratory , Teddington , UK , 2000 ). Broughton , W. R. , Crocker , L. E. , and Urquhart , J. M. , Strength of Adhesive Joints: A Parametric Study , NPL MATC(A) 27 ( National Physical Laboratory , Teddington , UK , 2000 ). Dean , G. D. , Crocker , L. E. , Read , B. , and Wright , L. , Int. J. Adhes. Adhes. 24 , 295 – 306 ( 2004 ). Adams , R. D. , Coppendale , J. , Mallick , V. , and Al-Hamdan , H. , Int. J. Adhes. Adhes. 12 ( 3 ), 185 – 190 ( 1992 ). Wang , C. H. and Chalkley , P. , Int. J. Adhes. Adhes. 20 ( 2 ), 155 – 164 ( 2000 ). Adams , R. D. , The Mechanics of Bonded Joints Structural Adhesives in Engineering ( ImechE Conference Publications , Suffolk , UK 1986 ). Harris , J. A. and Adams , R. D. , Int. J. Adhes. Adhes. 4 ( 2 ), 65 – 78 ( 1984 ). Crocombe , A. D. , Int. J. Adhes. Adhes. 15 ( 1 ), 21 – 27 ( 1995 ). Zgoul , M. and Crocombe , A. D. , Int. J. Adhes. Adhes. 24 ( 4 ), 355 – 366 ( 2004 ). Adams , R. D. and Harris , J. A. , Int. J. Adhes. Adhes. 7 ( 2 ), 69 – 80 ( 1987 ). ]. On the other hand, the load capabilities of adhesively bonded joints are affected by both applied pressure and temperature during cure. For this reason, in this study, the tensile load capabilities of single lap joints (SLJs) bonded with a flexible adhesive that possesses pressure-sensitive properties were experimentally investigated with respect to the applied pressure during the curing operation, and the experimental results were compared with finite element analysis (FEA) results. Finally, in addition to other parameters, such as the dependence on strain rate and the lack of yield criteria of adhesives, it was seen that the residual thermal stresses that occurred as a result of the applied pressure during the curing process at elevated temperature need to be taken into consideration to accurately simulate the mechanical behavior of adhesively bonded joints.     

Accumulation of Methylene Blue Dye by Growing Lemna minor

In the present investigation bioaccumulation studies were performed for the removal of Methylene Blue dye from an aqueous solution using live Lemna minor. The effect of various parameters such as the biosorbent dosage (1–3 g), pH (3-8 O'Mahony , T. ; Guibal , E. ; Tobin , J.M. ( 2002 ) Reactive dye biosorption by Rhizopus arrhizus biomass . Enzyme and Microbiology Technology , 31 : 456 . Ghosh , D. ; Bhattacharyya , K.G. ( 2002 ) Adsorption of Basic Blue 9 on kaolinite . Applied Clay Science , 20 : 295 . Avom , J. ; Mbadcam , J.K. ; Noubactep , C. ; Germain , P. ( 1997 ) Adsorption of Basic Blue 9 from an aqueous solution onto activated carbon from palm-tree cobs . Carbon , 35 : 365 . Willmott , N. ; Guthrie , J. ; Nelson , G. ( 1998 ) The biotechnology approach to colour removal from textile effluent . Journal of the Society of Dyers and Colourists , 114 : 38 . Otero , M. ; Rozada , F. ; Calvo , L.F. ; Garcia , A.I. ; Moran , A. ( 2003 ) Kinetic and equilibrium modelling of the Basic Blue 9 removal from solution by adsorbent materials produced from sewage sludges . Biochem. Eng. J , 15 : 59 . ASCE & AWWA ( 1990 ) In: American Society of Civil Engineers and American Water Works Association. Water treatment plant design. , 2nd Ed. ; Harold , B. , ed. ; McGraw-Hill : New York . ) and initial dye concentration (2–10 mg L^?1) were studied. The maximum uptake capacity of the Methylene Blue using L. minor was observed as 10.93 mg g^?1 at a biosorbent dosage of 1 g/300 mL, at pH 7 and at 10 mg L^?1 initial dye concentration. The surface morphology was analyzed using Scanning Electron Micrograph (SEM) for analyzing micro and macropores present on the surface of the plant and the functional groups on the biosorbent were analyzed using Fourier transform infrared analyzer (FTIR) for increasing the electrostatic attraction between the plant surface and the dye molecules by adjusting the pH of the solution. Equilibrium data was analyzed using Langmuir and Freundlich adsorption isotherm models. The Freundlich adsorption isotherm was found to be fitted well. The effect of initial dye concentration on the growth of the plant was studied by obtaining the growth profile of the plant on the basis of the relative growth rate (RGR).     

Removal of Cadmium Ions from Aqueous Samples by Synechocystis sp.

Abstract

The biosorption of cadmium ions from aqueous solution by dried, immobilized dried and immobilized live Synechocystis sp. was investigated. Sorption of plain Ca-alginate beads, which were used as substrate for immobilization, was also studied for comparison. Removal efficiency of biosorbents was studied as a function of pH (2-8 Volesky , B. ( 1990 ) Biosorption of Heavy Metals ; CRC Press : Boca Raton , FL . Wase , J. , Forster , C.F. (1997) Biosorbents for Metal Ions ; Taylor & Francis : London. Malkoç , E. ; Nuho?lu , Y. ( 2005 ) Investigations of nickel (II) removal from aqueous solutions using tea factory waste . J. Hazard. Mater. , 127 : 120 – 128 . Lodeiro , P. ; Cordero , B. ; Barriada , J.L. ; Herrero , R. ; Sastre de Vicente , M.E. ( 2005 ) Biosorption of cadmium by biomass of brown marine macroalgae . Bioresource Technol. , 96 : 1796 – 1803 . Shen , J. ; Duvnjak , Z. ( 2005 ) Adsorption isotherms for cupric and cadmium ions on corncob particles . Sep. Sci. Technol. , 40 : 1461 – 1481 . Kat?rc?o?lu , H. ; Asl?m , B. ; Türker , A.R. ; At?c? , T. ; Beyatl? , Y. ( 2008 ) Removal of cadmium(II) ion from aqueous system by dry biomass, immobilized live and heat-dried Oscillatoria sp. H1 isolated from freshwater (Mogan Lake) . Bioresource Technol. , 99 ( 10 ): 4185 – 4191 . Pavasant , P. ; Apiratikul , R. ; Sungkhum , V. ; Suthiparinyanont , P. ; Wattanachira , S. ; Marhaba , T.F. ( 2006 ) Biosorption of Cu²⁺, Cd²⁺, Pb²⁺, and Zn²⁺ using dried marine green macroalga Caulerpa lentillifera. Bioresource Technol. , 97 : 2321 – 2329 . ), temperature (20–40°C), initial cadmium ion concentration (50–300 mg/L), and contact time (0–120 min). The maximum biosorption capacities of the dried, immobilized dried, and immobilized live Synechocystis sp. and plain Ca-alginate beads were found as 75.7, 4.9, 4.3, and 3.9 mg/g, respectively at optimum conditions. Biosorption equilibrium was established in about 15 min. Dried biomass of Synechocystis sp. was found to be more suitable and an efficient biosorbent for the removal of cadmium ion from aqueous solution. Both of the isotherm models (Langmuir and Freundlich) were suitable for describing the biosorption of cadmium by the dried biomass of Synechocystis sp. All the tested cyanobacterial forms could be recovered more than 90% and reused in five biosorption–desorption cycles without any considerable loss in the biosorption capacity.     

Selective Separation of Nickel (II) and Cobalt (II) from Waste Water by Using Continuous Cross-Flow Micellar Enhanced Ultrafiltration with Addition of Chelating Agent

The performance of continuous cross-flow micellar enhanced ultrafiltration (MEUF) is evaluated for the selective separation of nickel (Ni²⁺) and cobalt (Co²⁺) from the aqueous stream using anionic surfactant sodiumdodecyl sulfate (SDS) and the mixture of the anionic and nonionic surfactant (SDS+TritonX-100) with the addition of iminodiacetic acid (IDA) as a chelating agent. Operating parameters like operating time (upto 100 min), cross flow rate (100–175 mL/min.), pH of the feed solution (3-6 Cheryan , M. ( 1998 ) Process Design in Ultrafiltration and Microfiltration Handbook ; Technomic Publishing Co. Inc : USA . Scamehorn , J.F. ; Ellington , R.T. ; Christian , S.D. ; Penny , B.W. ; Dunn , R.O. ; Bhat , S.N. ( 1986 ) Removal of multivalent metal cations from water using micellar-enhanced ultrafiltration . AIChE Symp. Ser. , 82 ( 250 ): 48 – 58 . Baek , K. ; Yang , J.W. ( 2004 ) Cross flow micellar-enhanced ultrafiltration for removal of nitrate and chromate: competitive binding . J. Hazard. Mater. , B108 : 119 – 123 . Yurlova , L. ; Kryvoruchko , A. ; Kornilovich , B. ( 2002 ) Removal of Ni (II) ions from waste- water by micellar-enhanced ultrafiltration . Desal. , 144 : 255 – 260 . ), molar concentration ratio of the chelating agent to metals (C/M ratio, 0.5–2.5), and molar concentration ratio of the surfactant to metals (S/M ratio, 5–9) were studied to investigate the effectiveness of the process on selective separation. For the single surfactant system at all empirically selected parameters, 92% Ni²⁺ in the permeate and 94% Co²⁺ in the retentate was achieved whereas for the mixed surfactant system 93% Ni²⁺ in permeate and 84% Co²⁺ in retentate was achieved. Flux variation for single and mixed surfactant system was studied. Flux observed for the single surfactant system was 36 L/m².h and for the mixed surfactant system was 31.5 L/m².h. Flux measurement also indicates insignificant fouling of the membrane.     

Selection of Experimental Domain using Two-Level Factorial Design to Determine Extract Yield,Antioxidant Capacity,Phenolics, and Flavonoids from Mangifera pajang Kosterm

Mangifera pajang Kosterm. is an important underutilized fruit of Malaysia. Two level factorial design was used for initial screening of the following independent factors, namely pH (2-6 Khoo , H.E. ; Prasad , K.N. ; Amin , I. ; Mohd-Esa , N. ( 2010 ) Carotenoids from Mangfera pajang and their antioxidant capacity . Molecules , 15 : 6699 . Fouad , A.S. ; Amin , I. ; Hamid , A.A. ; Azrina , A. ; Sadeq , H.A. ( 2011 ) Characterisation of fiber rich powder and antioxidant capacity of Mangifera pajang K. fruit peels . Food Chem. , 126 : 283 . Prasad , N.K. ; Chun , Y. ; En , Y. ; Zhao , M. ; Jiang , Y. (2009) Effects of high pressure on the extraction yield, total phenolic content and antioxidant activity of longan fruit pericarp. Inno Food Sci Emerg Technol. , 10: 155. Khiari , Z. ; Makris , D.P. ; Kefalas , P. ( 2009 ) An investigation on the recovery of antioxidant phenolics from onion solid wastes employing water/ethanol-based solvent systems . Food Bioprocess Technol. , 2 : 337 . Nemes , S.M. ; Orsat , N. ( 2010 ) Screening the experimental domain for the microwave-assisted extraction of secoisolariciresinol diglucoside from flaxseed prior to optimisation procedures . Food Bioprocess Technol. , 3 : 300 . ), ethanol concentration (20–80%), extraction temperature (30–65°C), time (30–240 min) and liquid to solid ratio (20–50 mL/g) to determine the extract yield, the antioxidant capacity, and the phenolic and flavonoid contents from Mangifera pajang pericarp. Among all the factors, ethanol concentration and liquid to solid ratio was very significant (p < 0.0001) in obtaining higher extract yield, antioxidant capacity, and phenolic content, whereas the pH, the extraction time, and temperature did not contribute significantly. From these results, we conclude that by altering ethanol concentration and liquid to solid ratio, significant differences can be noticed in obtaining high or lower concentrations on the recovery of extract yield, antioxidant capacity, and phenolic content.     

Effect of Surfactant Impregnation into Chitosan Hydrogel Beads Formed by Sodium Dodecyl Sulfate Gelation for the Removal of Congo Red

The effect of cetyltrimethylammonium bromide (CTAB) and triton X-100 (TX100) impregnation into chitosan hydrogel beads formed by sodium dodecyl sulfate (SDS) gelation (CSB) was investigated for the adsorption of Congo red (CR) from aqueous solutions. An impregnation of CTAB at 0.1 wt% into CSB increased adsorption from 97.46 mg/g to 113.24 mg/g, while 0.5 wt% TX100 impregnation into CSB registered a very small increase from 112.56 mg/g to 115.64 mg/g. CSB/CTAB exhibited similar adsorption at all pH levels (4-9 Gupta , V.K. ; Suhas , X. ( 2009 ) Application of low-cost adsorbents for dye removal–A review . J. Environ. Manage. , 90 ( 8 ): 2313 . Blackburn , R.S. ( 2004 ) Natural polysaccharides and their interactions with dye molecules: Applications in effluent treatment . Environ. Sci. Technol. , 38 ( 18 ): 4905 . Guibal , E. ( 2004 ) Interactions of metal ions with chitosan-based sorbents: A review . Sep. Purif. Technol. , 38 ( 1 ): 43 . No , H.K. ; Kim , S.D. ( 2006 ) Growth of soybean sprouts affected by chitosans prepared under various deproteinization and demineralization times . J. Sci. Food Agr. , 86 ( 9 ): 1365 . Ueno , H. ; Mori , T. ; Fujinaga , T. ( 2001 ) Topical formulations and wound healing applications of chitosan . Adv. Drug Deliver Rev. , 52 ( 2 ): 105 . Chatterjee , S. ; Lee , D.S. ; Lee , M.W. ; Woo , S.H. ( 2009 ) Enhanced adsorption of congo red from aqueous solutions by chitosan hydrogel beads impregnated with cetyl trimethyl ammonium bromide . Bioresource Technol. , 100 ( 11 ): 2803 . ), but CSB and CSB/TX100 showed lower adsorption at higher pH values. The Sips isotherm model was the best fit for all bead varieties, and the Sips maximum adsorption capacity value of CSB/CTAB (271.74 mg/g) was higher than that for CSB/TX100 (242.72 mg/g) or CSB without surfactant impregnation (174.83 mg/g). The experimental kinetic values of all varieties of beads for CR adsorption followed a pseudo-first-order rate model better than a pseudo-second-order rate model.     

Studies on Removal of Low Content Copper from the Sea Nodule Aqueous Solution using the Cationic Resin TP 207

Selective removal of copper remaining in the raffinate, obtained after solvent extraction of copper with LIX 84-I from the sea nodule leach solution, containing 0.512 g/L Cu(II), 0.212 g/L Fe(III), 15.16 g/L Ni(II), and 2.012 g/L Co(II), was carried out with TP 207, in the batch and column adsorption system. The operational factors affecting the copper adsorption such as initial copper ion concentration (0.05–1.0 g/L), pH (1–4 Jie , W.J. ; Xiu , Z.Q. ; Qing , Z.G. ; Ying , C.Z. ( 2010 ) Deep removal of copper from cobalt sulfate electrolyte by ion-exchange . T. Nonferr. Metal Soc. , 20 : 1534 – 1540 . Zhong , C.Q. ; Kang , M.X. ; Yan , M.A. ; Xia , Z.C. ( 2005 ) A Method of Removing Copper from Cobalt Electrolyte . [P] CN1598013A , 3 – 23 . (In Chinese). Nam , C.W. ; Kim , B.S. ; Park , K.H. ( 2003 ) Recovery of cobalt, nickel from manganese nodules by reduction roasting and smelting . Korean Soc. Geosyst. Eng. , 40 : 191 – 197 . Nam , C.W. ; Park , K.H. ; Kim , H.I. ( 2004 ) Sulphuric acid pressure leaching of Cu-Ni-Co-Fe matte . Korean Soc. Geosyst. Eng. , 419 : 413 – 417 . ), resin dosage (5–100 g/L), and temperature (293–338 K) were investigated. Adsorption of copper was found to be maximum at an equilibrium pH of 1.97 without any adsorption of other metal ions in the solution and was strongly affected by the resin dosage. Adsorption equilibrium data was well fitted with the Langmuir isotherm, and the monolayer adsorption capacity of copper ion was determined as 68.7 mg g^?1, at 298 K. The positive values of ΔH^o (11.5, 10.4, and 10.1 kJ mol^?1) determined at corresponding initial copper concentrations: 0.1, 0.3, and 0.5 g/L, respectively, in the solution, indicated that the adsorption was endothermic in nature. Kinetic studies confirmed that the adsorption of copper followed pseudo second order reaction with intra particle diffusion.     

DYNAMICS OF IMINE AND ACETOPHENONE DERIVATIVES IN SOLUTION STUDIED BY ONE-DIMENSIONAL DIFFUSION-ORDERED NMR SPECTROSCOPY (DOSY)

This paper describes the usefulness of one-dimensional diffusion-ordered NMR spectroscopy (1D-DOSY) in investigating dynamics and interactions of molecules in solution as well as in analyzing the structure of molecules. We synthesized the three imines, N-benzylidene-4-methylbenzene-Sulfonamide (1 Kondo, K., Kazuta, K., Saitoh, A. and Murakami, Y. 2003. Heterocycles, 59: 97–100.  [Google Scholar]), N-(4-chloro-benzylidene)4-methyl-benzene-sulfonamide (2 Horibe, H., Kazuta, K., Kotoku, M., Kondo, K., Okuno, H., Murakami, Y. and Aoyama, T. 2003. Synlett, : 2047–2051. [Web of Science ®] , [Google Scholar]), and N- (4-methoxybenzylidene)-4-methyl-benzene sulfonamide (3 Horibe, H., Fukuda, Y., Kondo, K., Okuno, H., Murakami, Y. and Aoyama, T. 2004. Tetrahedron, 60: 10701–10709. [Crossref], [Web of Science ®] , [Google Scholar]), and acetophenone (4 Sakamoto, Y., Kondo, K., Tokunaga, M., Kazuta, K., Fujita, H., Murakami, Y. and Aoyama, T. 2004. Heterocycles, 63: 1345–1357. [Crossref], [Web of Science ®] , [Google Scholar]) and its three derivatives, 4-chloroacetophenone (5 Sakamoto, Y., Kondo, K., Onozato, M. and Aoyama, T. 2006. Polycycl. Aromat. Comp., 26: 59–68. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), 4-nitro-acetophenone (6 Kondo, K., Kazuta, K., Fujita, H., Sakamoto, Y. and Murakami, Y. 2002. Tetrahedron, 58: 5209–5214. [Crossref], [Web of Science ®] , [Google Scholar]), and 4-methoxyaceto -phenone (7 Gostam, T., Morean, C., Jutean, A., Guichard, E. and Delsuc, M. A. 2004. Magn. Reson. Chem., 42: 496–499.  [Google Scholar]). 1D-DOSY was applied to a mixture of compounds (1 Kondo, K., Kazuta, K., Saitoh, A. and Murakami, Y. 2003. Heterocycles, 59: 97–100.  [Google Scholar]), (2 Horibe, H., Kazuta, K., Kotoku, M., Kondo, K., Okuno, H., Murakami, Y. and Aoyama, T. 2003. Synlett, : 2047–2051. [Web of Science ®] , [Google Scholar]), and (3 Horibe, H., Fukuda, Y., Kondo, K., Okuno, H., Murakami, Y. and Aoyama, T. 2004. Tetrahedron, 60: 10701–10709. [Crossref], [Web of Science ®] , [Google Scholar]) and to a mixture of compounds (4 Sakamoto, Y., Kondo, K., Tokunaga, M., Kazuta, K., Fujita, H., Murakami, Y. and Aoyama, T. 2004. Heterocycles, 63: 1345–1357. [Crossref], [Web of Science ®] , [Google Scholar]), (5 Sakamoto, Y., Kondo, K., Onozato, M. and Aoyama, T. 2006. Polycycl. Aromat. Comp., 26: 59–68. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]), (6 Kondo, K., Kazuta, K., Fujita, H., Sakamoto, Y. and Murakami, Y. 2002. Tetrahedron, 58: 5209–5214. [Crossref], [Web of Science ®] , [Google Scholar]), and (7 Gostam, T., Morean, C., Jutean, A., Guichard, E. and Delsuc, M. A. 2004. Magn. Reson. Chem., 42: 496–499.  [Google Scholar]). Although ¹ H NMR chemical shifts of the molecules in the mixtures resembled one another in the surrounding, we could distinguish signals of the individual molecules in each mixture on the basis of the NMR data and the values of the diffusion coefficient. Also, we could found the correlation of the measured diffusion coefficients and the calculated molecular volumes.     

Multistage point estimation methodologies for a negative exponential location under a modified linex loss function: Illustrations with infant mortality and bone marrow data

We have designed Stein-type (Stein, 1945 Stein, C. (1945). A Two Sample Test for a Linear Hypothesis Whose Power Is Independent of the Variance, Annals of Mathematical Statistics 16: 243–258.[Crossref] , [Google Scholar], Annals of Mathematical Statistics) two-stage, modified two-stage (Mukhopadhyay and Duggan, 1997 Mukhopadhyay, N. and Duggan, W. T. (1997). Can a Two-Stage Procedure Enjoy Second Order Properties? Sankhya, Series A 59: 435–448. [Google Scholar], Sankhya, Series A), and purely sequential strategies (Chow and Robbins, 1965 Chow, Y. S. and Robbins, H. (1965). On the Asymptotic Theory of Fixed Width Sequential Confidence Intervals for the Mean, Annals of Mathematical Statistics 36: 457–462.[Crossref] , [Google Scholar], Annals of Mathematical Statistics) to estimate an unknown location parameter of a negative exponential distribution having an unknown scale parameter under a newly defined and modified Linex loss function. We aim at controlling the associated risk function per unit cost by bounding it from above with a fixed preassigned positive number, ω, and we emphasize both asymptotic first-order and asymptotic second-order properties for the modified two-stage and purely sequential estimation strategies. In developing asymptotic second-order properties for the modified two-stage methodology, we have heavily relied upon basic ideas rooted in Mukhopadhyay and Duggan (1997 Mukhopadhyay, N. and Duggan, W. T. (1997). Can a Two-Stage Procedure Enjoy Second Order Properties? Sankhya, Series A 59: 435–448. [Google Scholar]). In developing asymptotic second-order properties for the purely sequential methodology, however, we have heavily relied upon nonlinear renewal theory (Lai and Siegmund, 1977 Lai, T. L. and Siegmund, D. (1977). A Nonlinear Renewal Theory with Applications to Sequential Analysis I, Annals of Statistics 5: 946–954.[Crossref], [Web of Science ®] , [Google Scholar], 1979 Lai, T. L. and Siegmund, D. (1979). A Nonlinear Renewal Theory with Applications to Sequential Analysis II, Annals of Statistics 7: 60–76.[Crossref], [Web of Science ®] , [Google Scholar], Annals of Statistics; Woodroofe, 1977 Woodroofe, M. (1977). Second Order Approximation for Sequential Point and Interval Estimation, Annals of Statistics 5: 984–995.[Crossref], [Web of Science ®] , [Google Scholar], Annals of Statistics). Then, we take to extensive data analysis carried out via computer simulations when requisite sample sizes range from small to moderate to large. We find that the Stein-type two-stage estimation methodology oversamples significantly and yet the achieved risk is not close to preset goal ω. On the other hand, both modified two-stage and purely sequential estimation strategies perform remarkably well. We have validated their main theoretical first-order and second-order properties through simulated data. The latter methodologies have been illustrated and implemented using two real data sets from health studies, namely, infant mortality data and bone marrow data.     

Mechanical Effect of Acetic Acid Lignin Adsorption on Honeycomb-Patterned Cellulosic Films

Abstract

We have already fabricated honeycomb-patterned cellulosic films with cellulose I and II polymorphisms as a basal framework in order to create an artificial woody cell wall.^{[ 1} Nemoto, J., Uraki, Y., Kishimoto, T., Sano, Y., Funada, R., Obata, N., Yabu, H., Tanaka, M. and Shimomura, M. 2005. Production of mesocopically patterned cellulose film. Bioresour. Technol., 96: 1955–1958.  [Google Scholar] ^{, 2} Uraki, Y., Nemoto, J., Otsuka, H., Tamai, Y., Sugiyama, J., Kishimoto, T., Ubukata, M., Yabu, H., Tanaka, M. and Shimomura, M. 2007. Honeycomb-like architecture produced by living bacteria, Gluconacetobacter xylinus. Carbohydr. Polym., 69: 1–6. [Crossref], [Web of Science ®] , [Google Scholar] ^] The adsorption of an isolated lignin, acetic acid lignin (AL), was attempted onto the honeycomb films not only to develop materials further mimicking the cell wall but also to elucidate the mechanical effect of isolated lignin on the tensile strength of the cellulosic architecture. The tensile strengths of honeycomb-patterned cellulosic films were improved by the AL adsorption. Although the cellulosic films without lignin weakened under high moisture content conditions as compared with those under the low content conditions, the lignin-adsorbed cellulosic film maintained significant tensile strength even under the high content conditions. This result suggests that lignin contributes to reinforce the mechanical strength of cellulose framework, in particular high moisture conditions.     

Aerosol Collection Efficiency of a Graded Metal-Fiber Filter at High Airflow Velocity (10 m s–1)

A non-woven graded metal-fiber filter was characterized for its collection efficiency as a function of particle size at an airflow velocity of 10 m s ^?1 . Efficiencies were determined by generating a monodisperse aerosol of polystyrene latex (PSL) spheres and oleic acid liquid particles of measured concentration with and without the filter present. For PSL spheres ≤0.7 μm, the collection efficiencies follow theoretical single-fiber collision efficiency (Ptak and Jaroszczyk 1990 Ptak, T. and Jaroszczyk, T. 1990. “Theoretical-Experimental Aerosol Filtration Model for Fibrous Filters at Intermediate Reynolds Numbers”. In Proceedings 5th World Filtration Congress, 566–572. France: Nice.  [Google Scholar]). Above 0.7 μm diameter (Stokes number 0.8), PSL collection efficiency exhibits a general decreasing trend with increasing particle size suggesting particle bounce. Although this trend is consistent with measured single-fiber collection (collision and adhesion) efficiency for Stokes numbers in the range of 0.2 to 22 (Rembor et al. 1999 Rembor, H.-J., Maus, R. and Umhauer, H. 1999. Measurements of Single Fibre Efficiencies at Critical Values of the Stokes Number. Part. Part. Syst. Charact, 16: 54–59. [Crossref], [Web of Science ®] , [Google Scholar]; Ptak and Jaroszczyk 1990 Ptak, T. and Jaroszczyk, T. 1990. “Theoretical-Experimental Aerosol Filtration Model for Fibrous Filters at Intermediate Reynolds Numbers”. In Proceedings 5th World Filtration Congress, 566–572. France: Nice.  [Google Scholar]), the magnitude of the filter efficiency is less. For 1 μm to 4 μm PSL, the average collection efficiency is 0.43 (expanded uncertainty (U) of 0.08, n = 6). In the case of particles having very different surface adhesion, e.g., oleic acid (sticky) aerosol, the collection efficiency for ≥1 μm diameter particles is nearly 1.00. This is in accordance with the theoretical collision efficiency as expected for particles with high adhesion. PSL tests performed on a filter coated with a synthetic-oil (aerosol) deposit (32.9 μg mm ^?2 ± 0.4 μg mm ^?2 ) improved the collection efficiency for PSL ≥ 0.7 μm to nearly 1.00. Particles that are deposited by interception-inertial impaction at 10 m s ^?1 airflow velocity depend on the particle and fiber adhesion properties.     

Monodisperse Droplet Generators as Potential Atomizers for Spray Drying Technology

Spray drying is a widely used unit operation for manufacturing powders of different characteristics. Many technological improvements have been made in the last few decades, and a great amount of research work is still being conducted. Recently, the hybrid spray-drying technique was reported, which combines the ink-jet technology with spray drying in order to produce particles of uniform characteristics.^[ 1-4 Patel , K.C. ; Chen , X.D. ; Lin , S.X.Q. Development of a laboratory ink-jet spray dryer . Chemeca 2006 , Auckland , New Zealand , September 17–20, 2006 (CD-Rom) . Patel , K.C. ; Chen , X.D. Drying of aqueous lactose solutions in a single stream dryer (S²D) . Transactions of the IChemE: Food and Bioproduct Processing 2007 , accepted . Patel , K.C. ; Chen , X.D. Production of spherical and uniform-sized particles using a laboratory ink-jet spray dryer . Asia-Pacific Journal of Chemical Engineering 2007 , 2 ( 5 ), 415 – 430 . Patel , K.C. ; Wu , W.D. ; Chen , X.D. Review on generation of monodisperse sprays for manufacturing micro-size uniform particles using a spray drying technology . In Proceedings of Asia-Pacific Drying Conference , Hong Kong , China , August 13–15, 2007 .  ^] The monodisperse droplet generators (MDGs) have certain features that make them attractive for use as atomizers in spray-drying operations. In this article, a comprehensive introduction to a variety of monodisperse droplet generators is provided. The advantages and limitations of these generators are discussed. The fundamental equations for predictions of the average droplet size are summarized. The discussion given in this study is aimed at the development of a hybrid technology that marries a suitable MDG with the existing spray-dryer technique (yet with some modifications) to manufacture the product with uniform characteristics containing micro- to nanosized particles.     

Two-stage estimation for a normal mean having a known lower bound of variance with final sample size defined via Gini’s mean difference and mean absolute deviation

Revisiting Stein (1945 Stein, C. (1945). A Two Sample Test for a Linear Hypothesis Whose Power Is Independent of the Variance, Annals of Mathematical Statistics 16: 243–258.[Crossref] , [Google Scholar], 1949 Stein, C. (1949). Some Problems in Sequential Estimation (Abstract), Econometrica 17: 77–78. [Google Scholar]) as well as Mukhopadhyay and Duggan (1997 Mukhopadhyay, N. and Duggan, W. T. (1997). Can a Two-Stage Procedure Enjoy Second-Order Properties? Sankhyā, Series A 59: 435–448. [Google Scholar]), we have proposed new two-stage procedures under both minimum risk point estimation and fixed-width confidence interval configurations for a normal mean μ when a lower bound of variance is known to us. New unbiased estimators based on sample standard deviation, Gini’s mean difference (GMD), and mean absolute deviance (MAD) are constructed to define the final sample sizes. The new procedures enjoy both asymptotic first-order and second-order properties, followed by simulated performances. Real data illustrations of the marigold data are also included.     

PREDICTION OF PRESSURE DROP IN A VENTURI SCRUBBER: EFFECT OF LIQUID FILM AND RE-ENTRAINMENT

A mathematical model has been developed for prediction of pressure drop in a Venturi scrubber. This model includes the effect of the amount of liquid film and re-entrainment of liquid droplets from liquid film. The result of the present model is compared with experimental data of Viswanathan et al. (1985) Viswanathan, S., Gnyp, W. A. and Pierre, St., C. 1985. Annular flow pressure drop model for pease-Anthony-type Venturi scrubbers. AIChE. J., 31(12): 1947–1958.  [Google Scholar] as well as with the other models (Viswanathan et al., 1985 Viswanathan, S., Gnyp, W. A. and Pierre, St., C. 1985. Annular flow pressure drop model for pease-Anthony-type Venturi scrubbers. AIChE. J., 31(12): 1947–1958.  [Google Scholar]; Boll, 1973 Boll, R. H. 1973. Particle collection and pressure drop in Venturi scrubbers. Ind. Eng. Chem. Fundam., 12: 40[Crossref], [Web of Science ®] , [Google Scholar]). Results of this study indicate that at high liquid to gas ratios prediction of pressure drop can be improved by considering re-entrainment and liquid film effects. Also the effects of gas velocity and liquid to gas ratio were investigated on the rate of droplet re-entrainment and pressure drop.     

DNA ADDUCTS OF BENZO[A]PYRENE- AND DIBENZO[A,L]PYRENE-DIOL EPOXIDES IN HUMAN LUNG EPITHELIAL CELLS: KINETICS OF ADDUCT REMOVAL,EFFECTS ON CELL CYCLE CHECKPOINTS,AND GENE EXPRESSION

The fjord-region PAH dibenzo[a,l]pyrene (DBP) is considerably more carcinogenic than the bay-region benzo[a]pyrene (BP). This fact can be ascribed to differences in DNA binding efficiency of their ultimate carcinogenic diol epoxide (DEs) intermediates, differences in structural features of the DNA adducts, and differences in DNA adduct recognition and the subsequent lesion removal by nucleotide excision repair (NER). In order to further substantiate previous findings in cell-free human systems (1 Buterin, T., Hess, M. T., Luneva, N., Geacintov, N. E., Amin, S., Kroth, H., Seidel, A. and Naegeli, H. 2000. Unrepaired Fjord Region Polycyclic Aromatic Hydrocarbon-DNA Adducts in Ras Codon 61 Mutational Hot Spots. Cancer Research, 60: 1849–1856.  [Google Scholar]), cultured cells (2 Luch, A., Kudla, K., Seidel, A., Doehmer, J., Greim, H. and Baird, W. M. 1999. The Level of DNA Modification by (+)-syn-(11S,12R,13S,14R)- and (?)-anti-(11R,12S,13S, 14R)-Dihydrodiol Epoxides of Dibenzo[a,l]pyrene Determined the Effect on the Proteins p53 and p21WAF1 in the Human Mammary Carcinoma Cell Line MCF-7. Carcinogenesis, 20: 859–865.  [Google Scholar]), and in rodents (3 Jankowiak, R., Ariese, F., Hewer, A., Luch, A., Zamzow, D., Hughes, N. C., Phillips, D., Seidel, A., Platt, K. L., Oesch, F. and Small, G. J. 1998. Structure, Conformations, and Repair of DNA Adducts from Dibenzo[a,l]pyrene: 32P-Postlabeling and Fluorescence Studies. Chemical Research in Toxicology, 11: 674–685.  [Google Scholar]) we have studied DNA adduct formation of anti-DE of DBP [(±)-anti-DBPDE], in A549 human epithelial lung carcinoma cells and monitored the levels of adducts as a function of time. A high-performance liquid chromatography (HPLC) procedure that allows monitoring of all cis- and trans-nucleoside adducts of dA and dG was used. Circular dichroism and UV-spectroscopy have been employed to gain information on adduct structural features. Incubation of cells with 0.1 μM (±)-anti-DBPDE resulted in rapid formation of adducts, followed by a decline. After 6 h of incubation about 20% of the adducts remained. Repeating the experiment with 0.01 μM (±)-anti-DBPDE resulted in a correspondingly lower adduct level initially, but in this case a larger proportion (35%) of the adducts remained after 6 h of incubation. Notably, at this time point, similar amounts of adducts are observed with both (±)-anti-DBPDE concentrations studied. Independent of diol epoxide concentration and incubation time, the dA/dG adducts were constant in number (～2.8). However, within the different adduct categories, the adduct distribution seemed to be time dependent. Although the data are preliminary, a selection with regard to adduct removal seems to have taken place. In comparative experiments with (+)-anti-BPDE, no significant difference in rates of adduct removal was evident. Preliminary results from global gene expression analysis, with focus on genes involved in DNA maintenance and cell cycle checkpoints, demonstrate interesting differences in the stress response elicited in the cells following exposure to the distorted and flexible nonplanar DBPDE or the rigid and planar BPDE molecule. As expected some major common induction events were clearly related to the activation of p53-dependent cell cycle checkpoint. However, distinct clusters of gene expression alterations were detected which mark one or other treatment specifically, indicating a high degree of subtlety in the stress response to closely related DNA adduct forming species.     

Design,synthesis, and preliminary evaluation as antimicrobial activity of novel spiro-1, 3-thiazolidine C-acyclic nucleoside analogs

Synthesis of a new class of 1, 3-thiazolidine nucleoside analogs is described. Reaction of 2-amino-2-deoxy-D-glucopyranose hydrochloride 2 with carbon disulfide yielded 5-hydroxy-4-(D-arabino-1, 2, 3, 4-tetrahydroxybutyl)-thiazolidin-2-thione 3, which on acetylation yielded 5-acetoxy-4-(D-arabino-1, 2, 3, 4-tetraacetoxy-butyl)-thiazolidin-2-thione 4. The acetylated sugar 4 reacted with hydrazonoyl chlorides 1a–f, affording the 5-acetoxy-4-(D-arabino-1, 2, 3, 4-tetraacetoxybutyl)-spiro-1 Chen, H., Fan, Y-H., Natarajan, A., Guo, Y., Iyasere, J., Harbinski, F., Luus, L., Christ, W., Aktas, H. and Halperin, J. A. 2004. Bioorg. Med. Chem. Lett., 14: 5401–5405. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] 3 Nasr, M. N., Gineinah, M. M. and El-Bendary, E. R. 2003. Arch. Pharm., 336: 560–566. [Crossref] , [Google Scholar]thiazolidine-2,2′ -1 Chen, H., Fan, Y-H., Natarajan, A., Guo, Y., Iyasere, J., Harbinski, F., Luus, L., Christ, W., Aktas, H. and Halperin, J. A. 2004. Bioorg. Med. Chem. Lett., 14: 5401–5405. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] 3 Nasr, M. N., Gineinah, M. M. and El-Bendary, E. R. 2003. Arch. Pharm., 336: 560–566. [Crossref] , [Google Scholar] 4 Belleau, B., Brasilli, L., Chan, L. and Zacheri, B. 1993. Cameron J. Bioorg. Med. Chem. Lett., 3: 1723–1928. [Crossref], [Web of Science ®] , [Google Scholar]thiadiazole derivatives 8a–f. The antibacterial activity of the novel 1, 3-thiazolidine-2,2′ -spiro- 1 Chen, H., Fan, Y-H., Natarajan, A., Guo, Y., Iyasere, J., Harbinski, F., Luus, L., Christ, W., Aktas, H. and Halperin, J. A. 2004. Bioorg. Med. Chem. Lett., 14: 5401–5405. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] 3 Nasr, M. N., Gineinah, M. M. and El-Bendary, E. R. 2003. Arch. Pharm., 336: 560–566. [Crossref] , [Google Scholar] 4 Belleau, B., Brasilli, L., Chan, L. and Zacheri, B. 1993. Cameron J. Bioorg. Med. Chem. Lett., 3: 1723–1928. [Crossref], [Web of Science ®] , [Google Scholar]thiadiazole nucleoside analogs is highlighted. All compounds with free NH group in the thiazolidine series 8a–f showed significant biological activity against all the standard strains.