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Sample records for pixe-aided immobilization study

  1. [Use of immobilization in the study of glyceraldehyde 3-phosphate dehydrogenase. Immobilized monomers].

    PubMed

    Muronets, V I; Ashmarina, L I; Asriiants, R A; Nagradova, N K

    1982-06-01

    Active immobilized monomers of glyceraldehyde 3-phosphate dehydrogenase were prepared by means of dissociation of the tetrameric enzyme molecule covalently bound to Sepharose via a single subunit. The conditions were elaborated to achieve the inactivation and solubilization of the non-covalently bound subunits leaving the monomer coupled to the matrix intact. This procedure differs from the previously developed method of matrix-bound oligomeric enzymes dissociation in a detail which was found to be essentially important. The widely used method includes complete denaturation of all subunits during treatment with urea followed by reactivation of the immobilized one, whereas only the non-covalently bound subunits suffer denaturation under the conditions developed in the present work. The immobilized monomers of glyceraldehyde 3-phosphate dehydrogenase exhibit Vmax and Km (for NAD and substrate) values similar to those found for the immobilized tetramer. Reassociation of the immobilized monomers with soluble enzyme subunits obtained in the presence of urea produces matrix-bound tetrameric species. Immobilized trimers ae formed upon incubation of matrix-bound monomers in a diluted apoenzyme solution. The immobilized monomeric, trimeric and tetrameric enzyme species were used to study the role of subunit interactions in cooperative phenomena exhibited by the dehydrogenase. PMID:7115810

  2. [sup 31]P NMR study of immobilized artificial membrane surfaces. Structure and dynamics of immobilized phospholipids

    SciTech Connect

    Qiu, X.; Pidgeon, C. )

    1993-11-25

    Chromatography surfaces were prepared by immobilizing a single-chain ether phospholipid at approximately a monolayer density on silica particles. The chromatography particles are denoted as [sup ether]IAM.PC[sup C10/C3], and they are stable to all solvents. The structure and dynamics of the interphase created by immobilizing phospholipids on silica particles were studied by [sup 31]P NMR methods. [sup ether]IAM.PC[sup C10/C3] spontaneously wets when suspended in both aqueous and organic solvents, and [sup 31]P NMR spectra were obtained in water, methanol, chloroform, acetonitrile, and acetone. [sup 31]P NMR spectra were subjected to line-shape analysis. From line-shape analysis, the correlation times for rapid internal motion ([tau]-PLL) and wobbling ([tau]-PRP) of the phospholipid headgroup were calculated for each solvent. Immobilized phospholipid headgroups comprising the IAM interfacial region undergo rapid reorientation similar to the case of the phospholipids forming liposome membranes with [tau]-PLL approximately 1 ns. Phospholipids in liposome membranes exhibit slower wobbling motion ([tau]-PRP approximately 1 ms) in the plane of the membrane. However, the immobilized phospholipids on [sup ether]IAM.PC[sup C10/C3] surfaces wobble with correlation times [tau]-PRP that depend on the solvent bathing the [sup ether]IAM.PC[sup C10/C3] surface. 41 refs., 9 figs., 2 tabs.

  3. Preliminary studies on immobilization of lipase using chicken eggshell

    NASA Astrophysics Data System (ADS)

    Salleh, S.; Serri, N. A.; Hena, S.; Tajarudin, H. A.

    2016-06-01

    A few advantages of enzyme immobilization are reusability of expensive enzyme, improvement of stability and activity compared to crude enzyme. Various organic components can be used as carrier for enzyme immobilization such as chicken eggshell. It can be used as a carrier for immobilization as its mineral component mostly contains of calcium carbonate. In the present study, Tributyrin method was used to test enzyme activity of Rhizomucour Miehei, Candida Antarctica and Candida Rugosa. Rhizomucour Miehei shows the highest enzyme activity (360.8 mol/min/mL lipase) and was used in further experiment. Experiment was continued to study incubation time for lipase immobilization on eggshell (1-4 hours) and reaction time of esterification of sugar ester (0-72 hours). Two hours incubation time for lipase immobilization was observed and gives the highest yield of sugar ester (78.13%). Fructose and stearic acid as substrate was used for the production of sugar ester. The highest percentage of sugar ester production was shown at 36 hours of reaction time.

  4. Use of immobilized enzymes in drug metabolism studies.

    PubMed

    Dulik, D M; Fenselau, C

    1988-04-01

    The immobilization of drug-metabolizing enzymes onto polymeric supports offers several advantages over use of conventional microsomal or soluble enzyme preparations. These include increased storage stability, facilitated separation of products from the incubation mixture, the ability to recover and reuse the enzyme catalyst, and in many cases, stabilization of the tertiary structure of membrane-bound enzymes. Attachment of the protein to the solid support may be accomplished by adsorption, covalent bonding, or entrapment techniques. This methodology has been successfully utilized for studies with such enzymes as cytochrome P-450, UDP-glucuronyltransferases, glutathione S-transferases, S-methyltransferases, and N-acetyltransferases. Although often employed for the synthesis of xenobiotic metabolites, immobilized enzymes have been used for mechanistic and relative reactivity studies, limited kinetic studies, and extracorporeal detoxification. Co-immobilization of multiple drug-metabolizing enzyme systems has made possible the sequential formation of metabolites arising from oxidation followed by conjugation. Immobilized enzymes may also be used in the prediction of species-dependent metabolic pathways. The potential for large-scale synthesis of drug metabolites using this methodology has been explored. PMID:3127263

  5. Study on algae removal by immobilized biosystem on sponge

    NASA Astrophysics Data System (ADS)

    Pei, Haiyan; Hu, Wenrong

    2006-10-01

    In this study, sponges were used to immobilize domesticated sludge microbes in a limited space, forming an immobilized biosystem capable of algae and microcystins removal. The removal effects on algae, microcystins and UV260 of this biosystem and the mechanism of algae removal were studied. The results showed that active sludge from sewage treatment plants was able to remove algae from a eutrophic lake’s water after 7 d of domestication. The removal efficiency for algae, organic matter and microcystins increased when the domesticated sludge was immobilized on sponges. When the hydraulic retention time (HRT) was 5h, the removal rates of algae, microcystins and UV260 were 90%, 94.17% and 84%, respectively. The immobilized biosystem consisted mostly of bacteria, the Ciliata and Sarcodina protozoans and the Rotifer metazoans. Algal decomposition by zoogloea bacteria and preying by microcreatures were the two main modes of algal removal, which occurred in two steps: first, absorption by the zoogloea; second, decomposition by the zoogloea bacteria and the predacity of the microcreatures.

  6. Platelet Immobilization on Supported Phospholipid Bilayers for Single Platelet Studies.

    PubMed

    Uhl, Eva; Donati, Alessia; Reviakine, Ilya

    2016-08-23

    The worldwide cardiovascular disease (CVD) epidemic is of grave concern. A major role in the etiology of CVDs is played by the platelets (thrombocytes). Platelets are anuclear cell fragments circulating in the blood. Their primary function is to catalyze clot formation, limiting traumatic blood loss in the case of injury. The same process leads to thrombosis in the case of CVDs, which are commonly managed with antiplatelet therapy. Platelets also have other, nonhemostatic functions in wound healing, inflammation, and tissue regeneration. They play a role in the early stages of atherosclerosis and the spread of cancer through metastases. Much remains to be learned about the regulation of these diverse platelet functions under physiological and pathological conditions. Breakthroughs in this regard are expected to come from single platelet studies and systems approaches. The immobilization of platelets at surfaces is advantageous for developing such approaches, but platelets are activated when they come in contact with foreign surfaces. In this work, we develop and validate a protocol for immobilizing platelets on supported lipid bilayers without activation due to immobilization. Our protocol can therefore be used for studying platelets with a wide variety of surface-sensitive techniques. PMID:27438059

  7. Subsurface Immobilization of Plutonium: Experimental and Model Validation Studies

    SciTech Connect

    Rittmann, Bruce E; Deo, Randhir P; Reed, Donald T

    2008-08-13

    We conducted a coordinated experimental and modeling study centered on the interaction of Shewanella alga BrY (S. alga) with plutonium species and phases. Plutonium is the key contaminant of concern at several DOE sites that are being addressed by the overall ERSP program. The over-arching goal of this research was to understand the long-term stability of bio-precipitated immobilized plutonium phases under changing redox conditions in biologically active systems. To initiate the process of plutonium immobilization, a side-by-side comparison of the bioreduction of uranyl and plutonyl species was conducted with S. alga. Uranyl was reduced in our system, consistent with literature reports, but we noted coupling between abiotic and biotic processes and observed that non-reductive pathways to precipitation typically exist. Additionally, a key role of biogenic Fe2+, which is known to reduce uranyl at low pH, is suggested. In contrast, residual organics, present in biologically active systems, reduce Pu(VI) species to Pu(V) species at near-neutral pH. The predominance of relatively weak complexes of PuO2+ is an important difference in how the uranyl and plutonyl species interacted with S. alga. Pu(V) also led to increased toxicity towards S. alga and is also more easily reduced by microbial activity. Biogenic Fe2+, produced by S. alga when Fe3+ is present as an electron acceptor, also played a key role in understanding redox controls and pathways in this system. Overall, the bioreduction of plutonyl was observed under anaerobic conditions, which favor its immobilization in the subsurface. Understanding the mechanism by which redox control is established in biologically active systems is a key aspect of remediation and immobilization strategies for actinides when they are present as subsurface contaminants.

  8. Effects of the immobilization supports on the catalytic properties of immobilized mushroom tyrosinase: a comparative study using several substrates.

    PubMed

    Marín-Zamora, María Elisa; Rojas-Melgarejo, Francisco; García-Cánovas, Francisco; García-Ruiz, Pedro Antonio

    2007-09-30

    Mushroom tyrosinase was immobilized from an extract onto glass beads covered with one of the following compounds: the crosslinked totally cinnamoylated derivatives of glycerine, D-sorbitol, D-manitol, 1,2-O-isopropylidene-alpha-D-glucofuranose, D-glucuronic acid, D-gulonic acid, sucrose, D-glucosone, D-arabinose, D-fructose, D-glucose, ethyl-D-glucopyranoside, inuline, dextrine, dextrane or starch, or the partially cinnamoylated derivative 3,5,6-tricinnamoyl-D-glucofuranose which was obtained by the acid hydrolysis of 1,2-O-isopropylidene-alpha-d-glucofuranose. The enzyme was immobilized by direct adsorption onto the support and the quantity of tyrosinase immobilized was found to increase with the hydrophobicity of the supports. The kinetic constants of immobilized tyrosinase acting on the substrates, 4-tert-butylcatechol, dopamine and DL-dopa, were studied. When immobilized tyrosinase acted on 4-tert-butylcatechol, the values of K(m)(app) were lower than these obtained for tyrosinase in solution while, when dopamine and DL-dopa were used, the K(m)(app) were higher. The order of the substrates as regards their ionizable groups, DL-dopa (two ionizable groups)>dopamine (one ionizable group)>4-tert-butylcatechol (no ionizable group) coincided with the order of the K(m)(app) values shown by tyrosinase immobilized on the hydrophobic supports, and was the inverse of that observed for tyrosinase in solution. The K(m)(app) values of immobilized tyrosinase were in all cases higher than those of soluble tyrosinase and depended on the nature of the support and the hydrophobicity of the substrate, meaning that it is possible to design supports with different degrees of selectivity towards a mixture of enzyme substrates in the reaction medium. PMID:17868943

  9. Studies on the thermal inactivation of immobilized enzymes

    SciTech Connect

    Ulbrich, R.; Schellenberger, A.; Damerau, W.

    1986-04-01

    The thermal inactivation of a great number of immobilized enzymes shows a biphasic kinetics, which distinctly differs from the first-order inactivation kinetics of the corresponding soluble enzymes. As shown for ..cap alpha..-amylase, chymotrypsin, and trypsin covalently bound to silica, polystyrene, or polyacrylamide, the dependence of the remaining activities on the heating time can be well described by the sum of two exponential terms. To interpret this mathematical model function, the catalytic properties of immobilized enzymes (number of active sites in silica-bound trypsin, Km and Ea values in silica-bound ..cap alpha..-amylase and chymotrypsin) at different stages of inactivation and the influence of various factors (coupling conditions, addition of denaturants or stabilizers, etc.) on the thermal inactivation of silica-bound ..cap alpha..-amylase were studied. Furthermore, conformational alterations in the thermal denaturation of spin-labeled soluble and silica-bound ..beta..-amylase were compared by electron spin resonance (ESR) studies. The results suggest that the biphasic inactivation kinetics reflects two different pathways according to which catalytically identical enzyme molecules are predominantly inactivated. 45 references.

  10. Nonporous magnetic materials as enzyme supports: studies with immobilized chymotrypsin.

    PubMed

    Munro, P A; Dunnill, P; Lilly, M D

    1977-01-01

    Chymotrypsin has been immobilized to several nonporous magnetic materials. Nickel particles were considered to be most suitable as immobilized enzyme supports. Chymotrypsin immobilized to nonporous magnetic supports was not fouled significantly by either whole milk or clarified yeast homogenate. AE-cellulose-chymotrypsin was rapidly fouled by both these materials and chymotrypsin immobilized to acrylic-based ion exchangers was slowly fouled. Immobilized enzyme activity was found to be inversely proportional to particle diameter for nonporous rock magnetic particles. Immobilization by adsorption and then glutaraldehyde crosslinking was used to produce controlled amounts of chymotrypsin on the particles. Esterolytic activity increased with enzyme loading but caseinolytic activity did not increase. Chymotrypsin is inhibited by metal ions from the magnetic supports. It is partially protected by use of a preliminary protein coating and may be reactivated by incubation with EDTA or BSA. PMID:14743

  11. Adhesion Peptide Immobilization on Electrospun Polymers: a Photoelectron Spectroscopy Study

    SciTech Connect

    Iucci, G.; Polzonetti, G.; Ghezzo, F.; Modesti, M.; Roso, M.; Dettin, M.

    2010-06-02

    The immobilization of an oligopeptide, mimicking the adhesion sequence of fibronectin, on the surface of polymer films prepared by electrospinning was investigated by XPS spectroscopy. Films of polycaprolactone (PCL) and poly(l-lactide-caprolactone)[P(LLA-CL)] were prepared by electrospinning onto aluminium substrates. A modified adhesion peptide containing a photoreactive group was immobilized on the surface of the polymer nanofibers by incubation in peptide solution and subsequent UV irradiation. XPS analysis yield evidence of successful peptide immobilization on the polymer surface; the amount of immobilized peptide increases with the concentration of the mother solution.

  12. Saccharides as Prospective Immobilizers of Nucleic Acids for Room-Temperature Structural EPR Studies.

    PubMed

    Kuzhelev, Andrey A; Shevelev, Georgiy Yu; Krumkacheva, Olesya A; Tormyshev, Victor M; Pyshnyi, Dmitrii V; Fedin, Matvey V; Bagryanskaya, Elena G

    2016-07-01

    Pulsed dipolar electron paramagnetic resonance (EPR) spectroscopy is a powerful tool for structural studies of biomolecules and their complexes. This method, whose applicability has been recently extended to room temperatures, requires immobilization of the studied biosystem to prevent averaging of dipolar couplings; at the same time, the modification of native conformations by immobilization must be avoided. In this work, we provide first demonstration of room-temperature EPR distance measurements in nucleic acids using saccharides trehalose, sucrose, and glucose as immobilizing media. We propose an approach that keeps structural conformation and unity of immobilized double-stranded DNA. Remarkably, room-temperature electron spin dephasing time of triarylmethyl-labeled DNA in trehalose is noticeably longer compared to previously used immobilizers, thus providing a broader range of available distances. Therefore, saccharides, and especially trehalose, can be efficiently used as immobilizers of nucleic acids, mimicking native conditions and allowing wide range of structural EPR studies at room temperatures. PMID:27320083

  13. Comperative study of catalase immobilization on chitosan, magnetic chitosan and chitosan-clay composite beads.

    PubMed

    Başak, Esra; Aydemir, Tülin; Dinçer, Ayşe; Becerik, Seda Çınar

    2013-12-01

    Catalase was immobilized on chitosan and modified chitosan. Studies were carried out on free-immobilized catalase concerning the determination of optimum temperature, pH, thermal, storage stability, reusability, and kinetic parameters. Optimum temperature and pH for free catalase and catalase immobilized were found as 35°C and 7.0, respectively. After 100 times of repeated tests, the immobilized catalases on chitosan-clay and magnetic chitosan maintain over 50% and 60% of the original activity, respectively. The ease of catalase immobilization on low-cost matrices and good stability upon immobilization in the present study make it a suitable product for further use in the food industry. PMID:23687952

  14. Biosorption of metal contaminants using immobilized biomass--Field studies

    SciTech Connect

    Jeffers, T.H.; Bennett, P.G.; Corwin, R.R.

    1993-01-01

    The US Bureau of Mines has developed porous beads containing immobilized biological materials such as sphagnum peat moss for extracting metal contaminants from waste waters. The beads, designated as BIO-FIX beads, have removed toxic metals from over 100 waters in laboratory tests. These waters include acid mine drainage (AMD) water from mining sites, metallurgical and chemical industry waste water, and contaminated ground water. Following the laboratory studies, cooperative field tests were conducted to evaluate the metal adsorption properties of the beads in column and low-maintenance circuits, determine bead stability in varied climatic situations, and demonstrate the beads' potential as a viable waste water treatment technique. Field results indicated that BIO-FIX beads readily adsorbed cadmium, lead, and other toxic metals from dilute waters; effluents frequently met drinking water standards and other discharge criteria. The beads exhibited excellent handling characteristics in both column and low-maintenance circuits, and continued to extract metal ions after repeated loading-elution cycles. Based on laboratory and field data, cost evaluations for using BIO-FIX technology to treat two AMD waters were prepared. Operating costs for BIO-FIX treatment, which ranged from $1.40 to $2.30 per 1,000 gal of water treated, were comparable with chemical precipitation costs.

  15. Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

    SciTech Connect

    Keith James Stanger

    2003-05-31

    The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-{alpha}-acetamidocinnamate (MAC), has the illustrated structure as established by {sup 31}P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]{sub 4}, [Rh(COD){sub 2}]{sup +}BF{sub 4}{sup -}, [Rh(COD)Cl]{sub 2}, and RhCl{sub 3} {center_dot} 3H{sub 2}O, adsorbed on SiO{sub 2} are optimally activated for toluene hydrogenation by pretreatment with H{sub 2} at 200 C. The same complexes on Pd-SiO{sub 2} are equally active without pretreatments. The active species in all cases is rhodium metal. The catalysts were characterized by XPS, TEM, DRIFTS, and mercury poisoning experiments. Rhodium on silica catalyzes the hydrogenation of fluorobenzene to produce predominantly fluorocyclohexane in heptane and 1,2-dichloroethane solvents. In heptane/methanol and heptane/water solvents, hydrodefluorination to benzene and subsequent hydrogenation to cyclohexane occurs exclusively. Benzene inhibits the hydrodefluorination of fluorobenzene. In DCE or heptane solvents, fluorocyclohexane reacts with hydrogen fluoride to form cyclohexene. Reaction conditions can be chosen to selectively yield fluorocyclohexane, cyclohexene, benzene, or cyclohexane. The oxorhenium(V) dithiolate catalyst [-S(CH{sub 2}){sub 3}s-]Re(O)(Me)(PPh{sub 3}) was modified by linking it to a tether that could be attached to a silica support. Spectroscopic investigation and catalytic oxidation reactivity showed the heterogenized catalyst's structure and reactivity to be similar to its homogeneous analog. However, the immobilized catalyst offered additional advantages of recyclability, extended stability, and increased resistance to deactivation.

  16. Spectroscopy study of Zn, Cd, Pb and Cr ions immobilization on C-S-H phase

    NASA Astrophysics Data System (ADS)

    Żak, Renata; Deja, Jan

    2015-01-01

    Calcium silicate hydrates (C-S-H) have a large number of structural sites available for cations and anions to bind. The C-S-H phases are materials which have ability to toxic ions immobilization. Immobilization mechanisms for C-S-H include sorption, phase mixing, substitution and precipitation of insoluble compounds. This study presents the C-S-H (prepared with C/S ratios 1.0) phase as absorbent for immobilization of Zn, Cd, Pb and Cr ions. The C-S-H spectra before and after incorporation of heavy metals ions into the C-S-H structure were obtained. The effect of added heavy metals ions on the hydration phenomena was studied by means of X-ray diffractions analysis. FTIR spectra was measured. The microstructure and phase composition of C-S-H indicate that they can play an essential role in the immobilization of heavy metals. The properties of C-S-H in the presence of Zn, Cd, Pb and Cr cations were studied. The leaching ML test was used to evaluate the level of immobilization of heavy metals in C-S-H. The leached solutions are diluted and analyzed using atomic absorption spectrometry (AAS) and the activated solid particles are separated, washed, desiccated and analyzed by Fourier transform infrared (FTIR) spectroscopy. It was found that the degree of Cd, Zn, Pb and Cr cations immobilization was very high (exceeding 99.96%).

  17. Spectroscopy study of Zn, Cd, Pb and Cr ions immobilization on C-S-H phase.

    PubMed

    Żak, Renata; Deja, Jan

    2015-01-01

    Calcium silicate hydrates (C-S-H) have a large number of structural sites available for cations and anions to bind. The C-S-H phases are materials which have ability to toxic ions immobilization. Immobilization mechanisms for C-S-H include sorption, phase mixing, substitution and precipitation of insoluble compounds. This study presents the C-S-H (prepared with C/S ratios 1.0) phase as absorbent for immobilization of Zn, Cd, Pb and Cr ions. The C-S-H spectra before and after incorporation of heavy metals ions into the C-S-H structure were obtained. The effect of added heavy metals ions on the hydration phenomena was studied by means of X-ray diffractions analysis. FTIR spectra was measured. The microstructure and phase composition of C-S-H indicate that they can play an essential role in the immobilization of heavy metals. The properties of C-S-H in the presence of Zn, Cd, Pb and Cr cations were studied. The leaching ML test was used to evaluate the level of immobilization of heavy metals in C-S-H. The leached solutions are diluted and analyzed using atomic absorption spectrometry (AAS) and the activated solid particles are separated, washed, desiccated and analyzed by Fourier transform infrared (FTIR) spectroscopy. It was found that the degree of Cd, Zn, Pb and Cr cations immobilization was very high (exceeding 99.96%). PMID:25106815

  18. Functionalized Graphene Sheets As Immobilization Matrix for Fenugreek β-Amylase: Enzyme Kinetics and Stability Studies

    PubMed Central

    Srivastava, Garima; Singh, Kritika; Talat, Mahe; Srivastava, Onkar Nath; Kayastha, Arvind M.

    2014-01-01

    β-Amylase finds application in food and pharmaceutical industries. Functionalized graphene sheets were customised as a matrix for covalent immobilization of Fenugreek β-amylase using glutaraldehyde as a cross-linker. The factors affecting the process were optimized using Response Surface Methodology based Box-Behnken design of experiment which resulted in 84% immobilization efficiency. Scanning and Transmission Electron Microscopy (SEM, TEM) and Fourier Tansform Infrared (FTIR) spectroscopy were employed for the purpose of characterization of attachment of enzyme on the graphene. The enzyme kinetic studies were carried out for obtaining best catalytic performance and enhanced reusability. Optimum temperature remained unchanged, whereas optimum pH showed shift towards acidic range for immobilized enzyme. Increase in thermal stability of immobilized enzyme and non-toxic nature of functionalized graphene can be exploited for production of maltose in food and pharmaceutical industries. PMID:25412079

  19. Functionalized graphene sheets as immobilization matrix for Fenugreek β-amylase: enzyme kinetics and stability studies.

    PubMed

    Srivastava, Garima; Singh, Kritika; Talat, Mahe; Srivastava, Onkar Nath; Kayastha, Arvind M

    2014-01-01

    β-Amylase finds application in food and pharmaceutical industries. Functionalized graphene sheets were customised as a matrix for covalent immobilization of Fenugreek β-amylase using glutaraldehyde as a cross-linker. The factors affecting the process were optimized using Response Surface Methodology based Box-Behnken design of experiment which resulted in 84% immobilization efficiency. Scanning and Transmission Electron Microscopy (SEM, TEM) and Fourier Tansform Infrared (FTIR) spectroscopy were employed for the purpose of characterization of attachment of enzyme on the graphene. The enzyme kinetic studies were carried out for obtaining best catalytic performance and enhanced reusability. Optimum temperature remained unchanged, whereas optimum pH showed shift towards acidic range for immobilized enzyme. Increase in thermal stability of immobilized enzyme and non-toxic nature of functionalized graphene can be exploited for production of maltose in food and pharmaceutical industries. PMID:25412079

  20. Immobilized low-level waste disposal options configuration study

    SciTech Connect

    Mitchell, D.E.

    1995-02-01

    This report compiles information that supports the eventual conceptual and definitive design of a disposal facility for immobilized low-level waste. The report includes the results of a joint Westinghouse/Fluor Daniel Inc. evaluation of trade-offs for glass manufacturing and product (waste form) disposal. Though recommendations for the preferred manufacturing and disposal option for low-level waste are outside the scope of this document, relative ranking as applied to facility complexity, safety, remote operation concepts and ease of retrieval are addressed.

  1. Adaptive Motor Imagery: A Multimodal Study of Immobilization-Induced Brain Plasticity.

    PubMed

    Burianová, Hana; Sowman, Paul F; Marstaller, Lars; Rich, Anina N; Williams, Mark A; Savage, Greg; Al-Janabi, Shahd; de Lissa, Peter; Johnson, Blake W

    2016-03-01

    The consequences of losing the ability to move a limb are traumatic. One approach that examines the impact of pathological limb nonuse on the brain involves temporary immobilization of a healthy limb. Here, we investigated immobilization-induced plasticity in the motor imagery (MI) circuitry during hand immobilization. We assessed these changes with a multimodal paradigm, using functional magnetic resonance imaging (fMRI) to measure neural activation, magnetoencephalography (MEG) to track neuronal oscillatory dynamics, and transcranial magnetic stimulation (TMS) to assess corticospinal excitability. fMRI results show a significant decrease in neural activation for MI of the constrained hand, localized to sensorimotor areas contralateral to the immobilized hand. MEG results show a significant decrease in beta desynchronization and faster resynchronization in sensorimotor areas contralateral to the immobilized hand. TMS results show a significant increase in resting motor threshold in motor cortex contralateral to the constrained hand, suggesting a decrease in corticospinal excitability in the projections to the constrained hand. These results demonstrate a direct and rapid effect of immobilization on MI processes of the constrained hand, suggesting that limb nonuse may not only affect motor execution, as evidenced by previous studies, but also MI. These findings have important implications for the effectiveness of therapeutic approaches that use MI as a rehabilitation tool to ameliorate the negative effects of limb nonuse. PMID:25477368

  2. Studies on immobilization of thorium in barium borosilicate glass

    NASA Astrophysics Data System (ADS)

    Mishra, R. K.; Sengupta, Pranesh; Kaushik, C. P.; Tyagi, A. K.; Kale, G. B.; Raj, Kanwar

    2007-02-01

    The barium borosilicate glass (BBS) matrix has shown considerable solubility of ThO2 at 1000 °C. As seen by X-ray diffractometry (XRD) and Electron probe micro analysis (EPMA) up to 15.86 wt% of ThO2 could be dissolved in this matrix. The homogeneity of thoria loaded glass was convincingly ascertained by EPMA. Attempts to load more than 16 wt% ThO2 led to the phase separation of crystalline phases identified as major phase of ThO2 and minor percentage of ThSiO4 phase with altogether different morphologies, as seen by XRD. Interestingly, the back scattered images of thorite crystals point towards the presence of chemical zoning. The results being reported in this paper are of interest especially with respect to immobilization of other actinides in borosilicate glass matrix.

  3. Study of cellulolytic enzyme immobilization on copolymers of N-vinylformamide.

    PubMed

    Tąta, Agnieszka; Sokołowska, Katarzyna; Świder, Joanna; Konieczna-Molenda, Anna; Proniewicz, Edyta; Witek, Ewa

    2015-10-01

    This study was focused on finding of effective carriers suitable for the immobilization of cellulase. Copolymers of N-vinylformamide (NFV) and divinylbenzene (DVB) were synthesized by free radical crosslinking polymerization in inverse suspension. Methyl silicone oil was used as the continuous phase. Three polymeric carriers based on P(NVF-co-DVB) with varying degrees of crosslinking and spherical particles with different grain sizes were obtained. The formamide groups in these carriers were hydrolyzed to amino groups, yielding three P(VAm-co-DVB) polymers with vinylamine units. Enzyme, cellulase (Novozym® 476), was immobilized onto carriers with vinylamine (through glutaraldehyde) and vinylformamide groups (without glutaraldehyde). The efficiency of the enzyme immobilization was determined based on the enzymatic activity of the enzyme during the catalytic reaction relative to that of the native enzyme. All tested carriers were found to be effective carriers for the immobilization of cellulase. However, the catalytic activity of cellulase immobilized on the P(VAM-co-DVB0.27)/2000/350 carrier was higher than that for the native enzyme. In addition, two molecular spectroscopy methods, Fourier-transform absorption infrared spectroscopy (FT-IR) and Fourier-transform Raman spectroscopy (FT-Raman), were used to analyze the carriers. These studies provided complete information regarding the structure of the studied copolymers. PMID:25978017

  4. Gamma radiation grafted polymers for immobilization of Brucella antigen in diagnostic test studies

    NASA Astrophysics Data System (ADS)

    Docters, E. H.; Smolko, E. E.; Suarez, C. E.

    The radiation grafting process has a wide field of industrial applications, and in the recent years the immobilization of biocomponents in grafted polymeric materials obtained by means of ionizing radiations is a new and important contribution to biotechnology. In the present work, gamma preirradiation grafting method was employed to produce acrylics hydrogels onto polyethylene (PE), polyvinyl chloride (PVC) and polystyrene (PS). Two monomers were used to graft the previously mentioned polymers: methacrylic acid (MAAc) and acrylamide (AAm), and several working conditions were considered as influencing the degree of grafting. All this grafted polymers were used to study the possibility of a subsequent immobilization of Brucella antigen (BAg) in diagnostic test studies (ELISA).

  5. Comparative study of 6-APA production by free and agar immobilized bacteria in nutrient broth culture.

    PubMed

    Dolui, A K; Das, S

    2011-04-01

    In the present study different bacterial samples were isolated from soil of different places of Dibrugarh and screened for biotransformation ability to produce 6-Aminopenicillanic acid. Among ten isolated bacterial samples, three gram positive bacterial samples designated as AKDD-2, AKDD-4 and AKDD-6 showed the production of 6-APA from penicillin G. Assessment of production of 6-APA after incubation in penicillin G (2 mg/ml) by three different samples separately in free and agar immobilization state was done by HPLC analysis. Reusability of immobilized cells was found successful up to 14 days. PMID:21614893

  6. Study of bone mineral metabolism. [during body immobilization, bed rest, and space flight

    NASA Technical Reports Server (NTRS)

    Palmer, H. E.

    1975-01-01

    The use of Sr-85 as an indicator of the skeletal location and relative amount of bone demineralization which occurs during immobilization of the body or body parts, bed-rest or space flight was studied. The bone mineral replacement which occurs after immobilization was measured rather than the bone loss which occurs during immobilization. In a study with two adult beagle dogs, the Sr-85 uptake in a leg which had been immobilized for two months was 400 percent higher than the uptake in the legs in regular use. This increased uptake probably resulted from only a few percent loss in bone mineral and indicates that losses less than one percent can be easily detected and located. The sensitivity, simplicity, and low radiation dose associated with the use of this method indicates that it should receive consideration for use on humans in bed-rest and space flight studies. Methods for measuring changes in total body nitrogen and in assisting the Johnson Space Center in calibrating a whole body counter for total body potassium measurements were also investigated.

  7. An immunohistochemical study of the sciatic nerve in a rat knee immobilization model.

    PubMed

    Yoshida, Shinya; Matsuzaki, Taro; Hoso, Masahiro

    2016-04-01

    [Purpose] This study was performed to immunohistochemically evaluate changes in the periphery of the sciatic nerve in a rat model of knee immobilization, and to assess the effects of range of motion exercise. [Subjects and Methods] Twenty-one male rats were divided randomly into three groups: control (C), immobilized (I), and exercise (E group). Rats in the I and E groups had the right knee joint immobilized for 2 weeks. In the E group, range of motion exercise was also performed. After the experimental period, the periphery of the sciatic nerve was immunohistochemically observed. [Results] Immunohistochemical staining revealed that the myelin sheath and the perineurium in all groups were laminin positive. In the C and E groups, all rats showed normal staining. In contrast, 4 rats in the I group exhibited weak labeling. [Conclusion] Our results suggest that immobilization alters the perineurium at a molecular level and the range of motion exercise is essential for maintaining the environment of the perineurium. PMID:27190437

  8. An immunohistochemical study of the sciatic nerve in a rat knee immobilization model

    PubMed Central

    Yoshida, Shinya; Matsuzaki, Taro; Hoso, Masahiro

    2016-01-01

    [Purpose] This study was performed to immunohistochemically evaluate changes in the periphery of the sciatic nerve in a rat model of knee immobilization, and to assess the effects of range of motion exercise. [Subjects and Methods] Twenty-one male rats were divided randomly into three groups: control (C), immobilized (I), and exercise (E group). Rats in the I and E groups had the right knee joint immobilized for 2 weeks. In the E group, range of motion exercise was also performed. After the experimental period, the periphery of the sciatic nerve was immunohistochemically observed. [Results] Immunohistochemical staining revealed that the myelin sheath and the perineurium in all groups were laminin positive. In the C and E groups, all rats showed normal staining. In contrast, 4 rats in the I group exhibited weak labeling. [Conclusion] Our results suggest that immobilization alters the perineurium at a molecular level and the range of motion exercise is essential for maintaining the environment of the perineurium. PMID:27190437

  9. Macro kinetic studies for photocatalytic degradation of benzoic acid in immobilized systems.

    PubMed

    Mehrotra, Kanheya; Yablonsky, Gregory S; Ray, Ajay K

    2005-09-01

    Semiconductor photocatalytic process has been studied extensively in recent years due to its intriguing advantages in environmental remediation. In this study, a two-phase swirl-flow monolithic-type reactor is used to study the kinetics of photocatalytic degradation of benzoic acid in immobilized systems. Transport contributions into the observed degradation rates were determined when catalyst is immobilized. Intrinsic kinetic rate constants and its dependence on light intensity and catalyst layer thickness, values of adsorption equilibrium constant, internal as well as external mass transfer parameters were determined. The simultaneous effect of catalyst loading and light intensity and optimum catalyst layer thickness were also determined experimentally. Reaction rate constants and overall observed degradation rates were compared with slurry systems. PMID:16054912

  10. Kinetic modeling and docking study of immobilized lipase catalyzed synthesis of furfuryl acetate.

    PubMed

    Mathpati, Ashwini C; Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2016-03-01

    The present work deals with the kinetic modeling and docking study for the furfuryl acetate synthesis using immobilized Burkholderia cepacia (BCL) lipase. Initially various lipases were immobilized on hydroxypropyl methyl cellulose (HPMC) and poly vinyl alcohol (PVA) base hybrid polymer matrix. After screening of various immobilized biocatalysts, HPMC:PVA:BCL was found to be a robust biocatalyst. Various reaction conditions were optimized using response surface methodology (RSM) based on a four-factor-three-level Box-Behnken design. The optimal conditions were obtained at molar ratio of 1:2 of furfuryl alcohol to acyl donor, temperature 50°C with catalyst loading of 30mg in 3mL of non-aqueous media toluene. Under these conditions 99.98% yield was obtained in 3h. The Arrhenius plot showed that the activation energy for furfuryl acetate synthesis was 10.68kcal/mol. The kinetics of reaction was studied close to optimized conditions which obey order bi-bi model. Molecular docking study was carried out to understand the active site of BCL which is responsible for the reaction. It was observed that the reaction proceeds via acylation of the active serine of BCL and demonstrating strong hydrogen bond between the substrate and histidine site. The catalyst recyclability study was carried up to five cycles. PMID:26827768

  11. Study of acetic acid production by immobilized acetobacter cells: oxygen transfer

    SciTech Connect

    Ghommidh, C.; Navarro, J.M.; Durand, G.

    1982-03-01

    The immobilization of living Acetobacter cells by adsorption onto a large-surface-area ceramic support was studied in a pulsed flow reactor. The high oxygen transfer capability of the reactor enabled acetic acid production rates up to 10.4 g/L/h to be achieved. Using a simple mathematical model incorporating both internal and external mass transfer coefficients, it was shown that oxygen transfer in the microbial film controls the reactor productivity. (Refs. 10).

  12. Self-assembled monolayers for studying enzyme immobilization and ion recognition

    NASA Astrophysics Data System (ADS)

    Kang, Jie

    This thesis explores the use of self-assembled monolayers on gold for studying enzyme immobilization and ion recognition. Chapter 1 serves as a general introduction to biosensing, self-assembled monolayers, protein immobilization, and surface characterization techniques. Chapter 2 through Chapter 5 describe the immobilization of a redox enzyme, glucose oxidase, to a variety of functional self-assembled monolayers by either noncovalent adsorption or covalent attachment. The characteristics of different immobilization methods are investigated, and the activity of the immobilized enzyme is assessed electrochemically. Chapter 2 presents detailed procedures for measuring glucose oxidase activity by an electrochemical technique---cyclic voltammetry. Chapter 3 describes the adsorption of glucose oxidase to hydrophobic and hydrophilic self-assembled monolayers (SAMs). Significant glucose oxidase adsorption to hydrophobic, methyl-terminated SAMs was observed, while long chain, hydrophilic SAMs terminated by hydroxyl and carboxyl groups resist enzyme adsorption. Chapter 4 examines the covalent attachment of glucose oxidase to N-hydroxysuccinimide ester (NHS ester)-terminated self-assembled monolayers. The reactivity of the surface NHS ester group is found to increase as its coverage is lowered. This observation is explained by the steric effect. Chapter 5 reports the electrostatic adsorption of glucose oxidase to self-assembled monolayers of cystamine. The adsorbed enzyme shows superior activity to enzyme immobilized by other means. The rate constants of surface enzyme catalysis are determined and compared with those of the enzyme in solution. Chapter 6 is concerned with iron (III) recognition by a self-assembled monolayer terminated with a siderophore group, desferrioxamine (H3DFO). We first demonstrate that the iron coverage of the ferrioxamine (FeDFO)-terminated SAM can be successfully assayed by cyclic voltammetry. We then present results for iron (III) binding to the H3

  13. Hydrated lime for metals immobilization and explosives transformation: Treatability study.

    PubMed

    Martin, W Andy; Larson, S L; Nestler, C C; Fabian, G; O'Connor, G; Felt, D R

    2012-05-15

    Fragmentation grenades contain Composition B (RDX and TNT) within a steel shell casing. There is the potential for off-site migration of high explosives and metals from hand grenade training ranges by transport in surface water and subsurface transport in leachate. This treatability study used bench-scale columns and mesocosm-scale laboratory lysimeters to investigate the potential of hydrated lime as a soil amendment for in situ remediation of explosives and metals stabilization in hand grenade range soils. Compared to the unamended soil there was a 26-92% reduction of RDX in the leachate and runoff water from the lime treated soils and a 66-83% reduction of zinc in the leachate and runoff water samples; where the hand grenade range metals of concern were zinc, iron, and manganese. The amended soil was maintained at the target pH of greater than 10.5 for optimum explosives decomposition. The treatability study indicated a high potential of success for scale-up to an in situ field study. PMID:22445717

  14. Subsurface Bio-Immobilization of Plutonium: Experiment and Model Validation Study

    SciTech Connect

    Reed, Donald; Rittmann, Bruce

    2006-06-01

    The goal of this project is to conduct a concurrent experimental and modeling study centered on the interactions of Shewanella algae BrY with plutonium and uranium species and phases. The most important objective of this research is to investigate the long-term stability of bioprecipitated immobilized actinide phases under changing redox conditions in biologically active systems. The long-term stability of bio-immobilized actinides (e.g. by bio-reduction) is a key criteria that defines the utility and effectiveness of a remediation/containment strategy for subsurface actinide contaminants. Plutonium, which is the focus of this project, is the key contaminant of concern at several DOE sites.

  15. Covalent Immobilization of Biotin on Magnetic Nanoparticles: Synthesis, Characterization, and Cytotoxicity Studies.

    PubMed

    Islam, Md Rafiqul; Bach, Long Giang; Vo, Thanh-Sang; Lim, Kwon Taek

    2015-01-01

    A simple protocol for covalent immobilization of biotin onto the surface of Fe3O4 magnetic nanoparticles (MNPs) for improving the biocompatibility of original MNPs has been realized. MNPs were first prepared by co-precipitation method which was subsequently anchored with functionalized biotin. The as-synthesized MNPs were observed to be monocrystalline as evidenced from XRD and TEM images. The covalent grafting of biotin to MNPs was confirmed by FT-IR. The XPS analysis suggested the successful preparation of Biotin-f-MNPs. The as-synthesized Biotin-f-MNPs were found to be superparamagnetic character as recorded by SQUID. Cell viability studies revealed that the biocompatibility of MNPs was improved upon Biotin immobilization. PMID:26328324

  16. Mechanism study of dual-frequency ultrasound assisted enzymolysis on rapeseed protein by immobilized Alcalase.

    PubMed

    Wang, Bei; Meng, Tingting; Ma, Haile; Zhang, Yanyan; Li, Yunliang; Jin, Jian; Ye, Xiaofei

    2016-09-01

    The mechanism of ultrasound field promoting enzymolysis efficiency is difficult to study, because the reaction system mixes with enzymes, proteins and hydrolysates. Immobilized enzyme is a good option that can be used to investigate the mechanism by separating enzymes out from the system after enzymolysis. The objective of this study was by using immobilized Alcalase to investigate the effects and mechanisms of the promotion of dual-frequency ultrasound (DFU) assisted-enzymolysis on rapeseed protein. Based on single factor experiments, response surface methodology model with three factors - hydrolysis time, power density and solid-liquid ratio at three levels was utilized to optimize the degree of hydrolysis (DH). Circular dichroism (CD) was used to analyze the secondary structure change of the protein, scanning electron microscopy (SEM) was used to analyze the surface microstructure change of the enzyme. The results showed that with DFU assisted-enzymolysis, the DH increased by 74.38% at the optimal levels for power density 57W/L, solid-liquid ratio 5.3g/L and enzymolysis time 76min. After DFU assisted-enzymolysis, the yield of soluble solids content, including protein, peptides and total sugar in hydrolysate increased by 64.61%, 40.88% and 23.60%, respectively. CD analysis showed that after DFU assisted-enzymolysis, the number of α-helix and random coil decreased by 10.7% and 4.5%, β-chain increased by 2.4%. SEM showed that the degree of surface roughness of immobilized Alcalase increased. The above results indicated that the improvement of hydrolysis by DFU assisted-enzymolysis was achieved by enhancing the solid solubility, changing the molecular structure of protein and increased the surface area of immobilized enzyme. PMID:27150775

  17. Glyphosate degradation by immobilized bacteria: laboratory studies showing feasibility for glyphosate removal from waste water.

    PubMed

    Heitkamp, M A; Adams, W J; Hallas, L E

    1992-09-01

    To evaluate immobilized bacteria technology for the removal of low levels of glyphosate (N-phosphonomethylglycine) from aqueous industrial effluents, microorganisms with glyphosate-degrading activity obtained from a fill and draw enrichment reactor inoculated with activated sludge were first exposed to glyphosate production wastes containing 500-2000 mg glyphosate/L. The microorganisms were then immobilized by adsorption onto a diatomaceous earth biocarrier contained in upflow Plexiglas columns. The columns were aerated, maintained at pH 7.0-8.0, incubated at 25 degrees C, supplemented with NH4NO3 (50 mg/L), and exposed to glyphosate process wastes pumped upflow through the biocarrier. Glyphosate degradation to aminomethylphosphonic acid was initially > 96% for 21 days of operation at flows yielding hydraulic residence times (HRTs) as short as 42 min. Higher flow rate studies showed > 98% removal of 50 mg glyphosate/L from the waste stream could be achieved at a HRT of 23 min. Glyphosate removal of > 99% at a 37-min HRT was achieved under similar conditions with a column inoculated with a pure culture of Pseudomonas sp. strain LBr, a bacterium known to have high glyphosate-degrading activity. After acid shocking (pH 2.8 for 18 h) of a column of immobilized bacteria, glyphosate-degrading activity was regained within 4 days without reinoculation. Although microbial growth and glyphosate degradation were not maintained under low organic nutrient conditions in the laboratory, the low levels of degradable carbon (45-94 mg/L) in the industrial effluent were sufficient to support prolonged glyphosate-degrading activity. The results demonstrated that immobilized bacteria technology is effective in removing low levels of glyphosate in high-volume liquid waste streams. PMID:1464067

  18. Comparative study of free and immobilized lipase from Bacillus aerius and its application in synthesis of ethyl ferulate.

    PubMed

    Saun, Nitin Kumar; Narwal, Sunil Kumar; Dogra, Priyanka; Chauhan, Ghanshyam Singh; Gupta, Reena

    2014-01-01

    In the present study, a purified lipase from Bacillus aerius immobilized on celite matrix was used for synthesis of ethyl ferulate. The celite-bound lipase exposed to glutaraldehyde showed 90.02% binding efficiency. It took two hours to bind maximally onto the support. The pH and temperature optima of the immobilized lipase were same as those of free enzyme i.e 9.5 and 55°C. Among different substrates both free and immobilized lipase showed maximum affinity towards p-nitrophenyl palmitate (p-NPP). The lipase activity was found to be stimulated in the presence of Mg(2+) in case of free enzyme while Zn(2+) and Fe(3+) showed stimulatory effect on immobilized lipase whereas salt ions as well as chelating agents inhibited activity of both free and immobilized lipase. Maximum enzyme activity was observed in n-hexane as organic solvent followed by n-heptane for both free and immobilized lipase, however CCl4, acetone and benzene inhibited the enzyme activity. Moreover, all the selected detergents (SDS, Triton X-100, Tween 80 and Tween 20) had an inhibitory effect on both free and immobilized enzyme activity. The celite bound lipase (1.5%) efficiently performed maximum esterification (2.51 moles/l) of ethanol and ferulic acid (100 mM each, at a molar ratio of 1:3) when incubated at 55°C for 48 h resulting in the formation of ester ethyl ferulate. PMID:25099909

  19. Double-Barrier mechanism for chromium immobilization: A quantitative study of crystallization and leachability.

    PubMed

    Liao, Changzhong; Tang, Yuanyuan; Liu, Chengshuai; Shih, Kaimin; Li, Fangbai

    2016-07-01

    Glass-ceramics are well known for the excellent combination properties provided by their components, a glassy matrix and crystalline phases, and have promising applications in the immobilization and detoxification of solid waste containing toxic metals. Glass-ceramic products were successfully synthesized in CaO-MgO-SiO2-Al2O3 -Cr2O3 system. Two key measures--partitioning ratio of Cr in the spinel and Cr leaching ratio--were used to investigate the mechanism of Cr immobilization in the glass-ceramic products. The results of powder X-ray diffraction revealed that both spinel and diopside were major crystalline phases in the products. The value of x in the MgCr(x)Al(2-x)O4 spinel was highly related to the amount of Cr2O3 added to the glass-ceramic system. As Cr2O3 content increased, the proportion of spinel phase increased, while that of glass phase decreased. The partitioning ratio of Cr in spinel phase was about 70% for 2 wt.% Cr2O3, and increased to 90% when loaded with 10 wt.% of Cr2O3. According to the results of the prolonged toxicity characteristic leaching procedure, the Cr leaching ratio decreased with the increase of Cr partitioning ratio into the spinel phase. The findings of this study clearly indicate that glass-ceramic formed by spinel structure and residual glass successfully immobilized Cr. PMID:26994355

  20. Study on immobilization of yeast alcohol dehydrogenase on nanocrystalline Ni-Co ferrites as magnetic support.

    PubMed

    Shakir, Mohammad; Nasir, Zeba; Khan, Mohd Shoeb; Lutfullah; Alam, Md Fazle; Younus, Hina; Al-Resayes, Saud Ibrahim

    2015-01-01

    The covalent binding of yeast alcohol dehydrogenase (YADH) enzyme complex in a series of magnetic crystalline Ni-Co nanoferrites, synthesized via sol-gel auto combustion technique was investigated. The structural analysis, morphology and magnetic properties of Ni-Co nanoferrites were determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), vibrating-sample magnetometer (VSM), high resolution transmission electron microscopy (HRTEM) and Fourier transform infrared spectroscopy (FTIR). The comparative analysis of the HRTEM micrographs of bare magnetic nanoferrite particles and particles immobilized with enzyme revealed an uniform distribution of the particles in both the cases without undergoing change in the size which was found to be in the range 20-30 nm. The binding of YADH to Ni-Co nanoferrites and the possible binding mechanism have been suggested by comparing the FTIR results. The binding properties of the immobilized YADH enzyme were also studied by kinetic parameters, optimum operational pH, temperature, thermal stability and reusability. The immobilized YADH exhibits enhanced thermal stability as compared to the free enzyme over a wide range of temperature and pH, and showed good durability after recovery by magnetic separation for repeated use. PMID:25450541

  1. High pressure studies on hesperitin production with hesperidinase free and immobilized in calcium alginate beads

    NASA Astrophysics Data System (ADS)

    Furtado, Andreia; Rosário, Pedro M.; Calado, António R. T.; Alfaia, António J. I.; Ribeiro, Maria H. L.

    2012-03-01

    The use of high pressure for the enzymatic synthesis of pharmacologically interesting molecules is a very important tool. Hesperidin and hesperitin exhibit anti-inflammatory, antimicrobial, antioxidant, and anticarcinogenic properties and prevent bone loss. However, hesperidin has a low bioavailability compared with hesperitin, due to the rutinoside moiety attached to the flavonoid. The aim of this work was the enzymatic production of hesperitin from hesperidin (soluble and insoluble) with hesperidinase free and immobilized in Ca-alginate beads, under high pressure conditions. The work was focused on the optimization of enzyme activity, studying the effects: pressure (50-150 MPa), temperature (35-75 °C), concentration of substrate (100-800 mg/L), and immobilization of hesperidinase. An 18-fold increase in hesperidinase residual activity was observed under high pressure conditions of 100 MPa compared to 0.1 MPa. A higher specificity of the hydrolytic reaction under high pressure (100 MPa) with a two-and three-fold increase in the ratio K cat/K M (specificity constant) at 55 °C and 75 °C was observed. A two-fold increase in the maximum activity at 100 MPa was observed with immobilized hesperinase compared to 0.1 MPa. In the second reutilization, almost a four-fold increase was obtained under high pressure conditions in comparison to atmospheric pressure.

  2. An efficient TiO2 coated immobilized system for the degradation studies of herbicide isoproturon: durability studies.

    PubMed

    Verma, A; Prakash, N T; Toor, A P

    2014-08-01

    The investigation presents the observations on the use of cement beads for the immobilization of TiO2 for the degradation of herbicide isoproturon. The immobilized system was effective in degrading and mineralizing the herbicide for continuous thirty cycles without losing its durability. Catalyst was characterized by SEM-EDAX for checking the durability of the catalyst. The degradation rate followed first order kinetics as measured by change in absorption intensity in UV range as well as HPLC analysis. Two rounds of TiO2 coating on inert cement beads with average diameter 1.5cm at UV Intensity 25Wm(-2) calcined at 400°C were the optimized conditions for the degradation of herbicide isoproturon. More than 90% TOC and COD reduction along with ammonium ions generation (80%) confirmed the mineralization of isoproturon. Fixed bed baffled reactor studies under solar irradiations using the TiO2 immobilized beads confirmed 85% degradation after 6h. LC-MS studies confirmed the intermediates formation and their subsequent degradation using immobilized system. PMID:24873700

  3. Immobilized lysozyme for the continuous lysis of lactic bacteria in wine: Bench-scale fluidized-bed reactor study.

    PubMed

    Cappannella, Elena; Benucci, Ilaria; Lombardelli, Claudio; Liburdi, Katia; Bavaro, Teodora; Esti, Marco

    2016-11-01

    Lysozyme from hen egg white (HEWL) was covalently immobilized on spherical supports based on microbial chitosan in order to develop a system for the continuous, efficient and food-grade enzymatic lysis of lactic bacteria (Oenococcus oeni) in white and red wine. The objective is to limit the sulfur dioxide dosage required to control malolactic fermentation, via a cell concentration typical during this process. The immobilization procedure was optimized in batch mode, evaluating the enzyme loading, the specific activity, and the kinetic parameters in model wine. Subsequently, a bench-scale fluidized-bed reactor was developed, applying the optimized process conditions. HEWL appeared more effective in the immobilized form than in the free one, when the reactor was applied in real white and red wine. This preliminary study suggests that covalent immobilization renders the enzyme less sensitive to the inhibitory effect of wine flavans. PMID:27211619

  4. Kinetic studies on degradation of Reactive Red 120 dye in immobilized packed bed reactor by Bacillus cohnii RAPT1.

    PubMed

    Padmanaban, V C; Geed, Sachin RameshRao; Achary, Anant; Singh, R S

    2016-08-01

    The degradation of Reactive Red 120 using Bacillus cohnii RAPT1 immobilized on polyurethane was studied. Initial experiments indicated that the percentage removal of dye in immobilized batch was significantly higher than batch (without immobilization). The optimum process parameters such as effect of dye concentration, time of immobilization on Poly Urethane Foam, initial inoculum size, pH and temperature for removal of dye were investigated and was found as 200ppm, 36h, 300*10(6) colony forming units/ml, 8.0 and 35°C respectively. Under optimum conditions, 100% removal of dye was obtained within 4h. The kinetics of biodegradation for the batch with free cells and immobilised packed batch was found to be IInd order with kinetic constant and initial rate of reaction as 0.0408, 0.084L/(mgday) and 1632, 3360 (mg/Lday) respectively. PMID:26968121

  5. BIOINTERACTION ANALYSIS BY HIGH-PERFORMANCE AFFINITY CHROMATOGRAPHY: KINETIC STUDIES OF IMMOBILIZED ANTIBODIES

    PubMed Central

    Nelson, Mary Anne; Moser, Annette; Hage, David S.

    2009-01-01

    A system based on high-performance affinity chromatography was developed for characterizing the binding, elution and regeneration kinetics of immobilized antibodies and immunoaffinity supports. This information was provided by using a combination of frontal analysis, split-peak analysis and peak decay analysis to determine the rate constants for antibody-antigen interactions under typical sample application and elution conditions. This technique was tested using immunoaffinity supports that contained monoclonal antibodies for 2,4-dichlorophenoxyacetic acid (2,4-D). Association equilibrium constants measured by frontal analysis for 2,4-D and related compounds with the immobilized antibodies were 1.7–12 × 106 M−1 at pH 7.0 and 25°C. Split-peak analysis gave association rate constants of 1.4–12 × 105 M−1s−1 and calculated dissociation rate constants of 0.01–0.4 s−1 under the application conditions. Elution at pH 2.5 for the analytes from the antibodies was examined by peak decay analysis and gave dissociation rate constants of 0.056–0.17 s−1. A comparison of frontal analysis results after various periods of column regeneration allowed the rate of antibody regeneration to be examined, with the results giving a first-order regeneration rate constant of 2.4 × 10−4 s−1. This combined approach and the information it provides should be useful in the design and optimization of immunoaffinity chromatography and other analytical methods that employ immobilized antibodies. The methods described are not limited to the particular analytes and antibodies employed in this study but should be useful in characterizing other targets, ligands and supports. PMID:19394281

  6. Modification of silicon nitride surfaces with GOPES and APTES for antibody immobilization: computational and experimental studies

    NASA Astrophysics Data System (ADS)

    Dien To, Thien; Nguyen, Anh Tuan; Nhat Thanh Phan, Khoa; Thu Thi Truong, An; Doan, Tin Chanh Duc; Mau Dang, Chien

    2015-12-01

    Chemical modification of silicon nitride (SiN) surfaces by silanization has been widely studied especially with 3-(aminopropyl)triethoxysilane (APTES) and 3-(glycidyloxypropyl) dimethylethoxysilane (GOPES). However few reports performed the experimental and computational studies together. In this study, surface modification of SiN surfaces with GOPES and APTES covalently bound with glutaraldehyde (GTA) was investigated for antibody immobilization. The monoclonal anti-cytokeratin-FITC (MACF) antibody was immobilized on the modified SiN surfaces. The modified surfaces were characterized by water contact angle measurements, atomic force microscopy and fluorescence microscopy. The FITC-fluorescent label indicated the existence of MACF antibody on the SiN surfaces and the efficiency of the silanization reaction. Absorption of APTES and GOPES on the oxidized SiN surfaces was computationally modeled and calculated by Materials Studio software. The computational and experimental results showed that modification of the SiN surfaces with APTES and GTA was more effective than the modification with GOPES.

  7. Glyphosate degradation by immobilized bacteria: field studies with industrial wastewater effluent.

    PubMed Central

    Hallas, L E; Adams, W J; Heitkamp, M A

    1992-01-01

    Immobilized bacteria have been shown in the laboratory to effectively remove glyphosate from wastewater effluent discharged from an activated sludge treatment system. Bacterial consortia in lab columns maintained a 99% glyphosate-degrading activity (GDA) at a hydraulic residence time of less than 20 min. In this study, a pilot plant (capacity, 45 liters/min) was used for a field demonstration. Initially, activated sludge was enriched for microbes with GDA during a 3-week biocarrier activation period. Wastewater effluent was then spiked with glyphosate and NH4Cl and recycled through the pilot plant column during start-up. Microbes with GDA were enhanced by maintaining the pH at less than 8 and adding yeast extract (less than 10 mg/liter). Once the consortia were stabilized, the column capacity for glyphosate removal was determined in a 60-day continuous-flow study. Waste containing 50 mg of glyphosate per liter was pumped at increasing flow rates until a steady state was reached. A microbial GDA of greater than 90% was achieved at a 10-min hydraulic residence time (144 hydraulic turnovers per day). Additional studies showed that microbes with GDA were recoverable within (i) 5 days of an acid shock and (ii) 3 days after a 21-day dormancy (low-flow, low-maintenance) mode. These results suggest that full-scale use of immobilized bacteria can be a cost-effective and dependable technique for the biotreatment of industrial wastewater. PMID:1599241

  8. Study on Carrier Material of Immobilization Acetylcholinesterase For Biosensor in Detectionof Organophosphorus Pesticide Residues

    NASA Astrophysics Data System (ADS)

    Sun, Xia; Wang, Xiangyou; Jia, Chuandong

    A comparison between several immobilization materials of AChE on surface of glassy carbon electrode(GCE) was presented. The immobilization methods employed crosslinking method with glutaraldehyde as a cross-linking agent and bovine serum albumin(BSA) as a protectant, AChE was immobilized on different membranes including nylon membrane, cellulose nitrate membrane and chitosan membrane respectively. The enzyme membrane was then fixed on the surface of glassy carbon electrode(GCE) with O-ring to prepare an amperometric biosensor for the detection of organophosphorus pesticides. The activity of immobilization AChE was detected by measuring the oxidation current of thiocholine, the results showed that the activity of immobilization AChE were all different with different membrane as carrier material.Compared with nylon membrane and cellulose nitrate membrane, chitosan membrane was obviously good. So chitosan membrane can be selected as immobilized AChE carrier material.

  9. HPLC study on the stability of bendamustine hydrochloride immobilized onto polyphosphoesters.

    PubMed

    Pencheva, Ivanka; Bogomilova, Anita; Koseva, Neli; Obreshkova, Danka; Troev, Kolio

    2008-12-01

    Novel water soluble polymer complexes of bendamustine hydrochloride, a bifunctional alkylating agent with antimetabolic and cytotoxic activity, were developed using biodegradable polymer carriers-poly(oxyethylene H-phosphonate), poly(methyloxyethylene phosphate) and poly(hydroxyoxyethylene phosphate). Bendamustine hydrochloride was immobilized onto polyphosphoesters via covalent, ionic and hydrogen bonding. The structure of the complexes formed was elucidated by (1)H, (13)C, (31)P NMR and FT-IR spectroscopy. The chemical stability of bendamustine hydrochloride in the novel complexes was studied by HPLC analysis based on a validated method with appointed analytical parameters such as specificity, repeatability, limit of quantitation, limit of detection and linearity. The results from the HPLC indicate that in neutral (pH 7) and alkaline (pH 9) media bendamustine hydrochloride in the polymer complexes is more stable than the pure bendamustine hydrochloride. The enhanced stability of the immobilized drug is explained with the drug interaction with the polymer carriers or their degradation products. PMID:18926656

  10. Studies on immobilization and partial characterization of lipases from wheat seeds (Triticum aestivum).

    PubMed

    Pierozan, Morgana Karin; Oestreicher, Enrique Guillermo; Oliveira, J Vladimir; Oliveira, Débora; Treichel, Helen; Cansian, Rogério Luís

    2011-09-01

    The objective of this study was to provide some features on immobilization and partial characterization of lipases from wheat seeds. The optimum pH and temperature were found to be 5.5 and 32-37 °C, respectively. The stability of the concentrated enzymatic extract to high temperatures (25, 35, 45, and 55 °C) showed that the incubation of the extract at 55 °C led to its complete inactivation. The concentrated enzymatic extract kept 90% of its hydrolytic and esterification activities until 70 and 40 days of storage at 4 °C, respectively. The extract presented higher hydrolytic specificity to substrates of medium and long chains and higher esterification affinity to fatty acids of short and medium chains and alcohols with two and three carbon atoms. After the immobilization process using activated coal and sodium alginate as supports, an enhancement of about threefold in lipase activity was observed. The development of the present work permitted us to point out some characteristics of lipases from wheat seeds necessary for the proposition of new future industrial applications for this important biocatalyst. PMID:21468634

  11. Spectroscopic study of 3-Hydroxyflavone - protein interaction in lipidic bi-layers immobilized on silver nanoparticles.

    PubMed

    Voicescu, Mariana; Ionescu, Sorana; Nistor, Cristina L

    2017-01-01

    The interaction of 3-Hydroxyflavone with serum proteins (BSA and HSA) in lecithin lipidic bi-layers (PC) immobilized on silver nanoparticles (SNPs), was studied by fluorescence and Raman spectroscopy. BSA secondary structure was quantified with a deconvolution algorithm, showing a decrease in α-helix structure when lipids were added to the solution. The effect of temperature on the rate of the excited-state intra-molecular proton transfer and on the dual fluorescence emission of 3-HF in the HSA/PC/SNPs systems was discussed. Evaluation of the antioxidant activity of 3-HF in HSA/PC/SNPs systems was also studied. The antioxidant activity of 3-HF decreased in the presence of SNPs. The results are discussed with relevance to the secondary structure of proteins and of the 3-HF based nano-systems to a topical formulation useful in the oxidative stress process. PMID:27380623

  12. Immobilized Kluyveromyces marxianus cells in carboxymethyl cellulose for production of ethanol from cheese whey: experimental and kinetic studies.

    PubMed

    Roohina, Fatemeh; Mohammadi, Maedeh; Najafpour, Ghasem D

    2016-09-01

    Cheese whey fermentation to ethanol using immobilized Kluyveromyces marxianus cells was investigated in batch and continuous operation. In batch fermentation, the yeast cells were immobilized in carboxymethyl cellulose (CMC) polymer and also synthesized graft copolymer of CMC with N-vinyl-2-pyrrolidone, denoted as CMC-g-PVP, and the efficiency of the two developed cell entrapped beads for lactose fermentation to ethanol was examined. The yeast cells immobilized in CMC-g-PVP performed slightly better than CMC with ethanol production yields of 0.52 and 0.49 g ethanol/g lactose, respectively. The effect of supplementation of cheese whey with lactose (42, 70, 100 and 150 g/l) on fermentative performance of K. marxianus immobilized in CMC beads was considered and the results were used for kinetic studies. The first order reaction model was suitable to describe the kinetics of substrate utilization and modified Gompertz model was quite successful to predict the ethanol production. For continuous ethanol fermentation, a packed-bed immobilized cell reactor (ICR) was operated at several hydraulic retention times; HRTs of 11, 15 and 30 h. At the HRT of 30 h, the ethanol production yield using CMC beads was 0.49 g/g which implies that 91.07 % of the theoretical yield was achieved. PMID:27126500

  13. Evaluation of capillary chromatographic supports for immobilized human purine nucleoside phosphorylase in frontal affinity chromatography studies.

    PubMed

    de Moraes, Marcela Cristina; Temporini, Caterina; Calleri, Enrica; Bruni, Giovanna; Ducati, Rodrigo Gay; Santos, Diógenes Santiago; Cardoso, Carmen Lucia; Cass, Quezia Bezerra; Massolini, Gabriella

    2014-04-18

    The aim of this work was to optimize the preparation of a capillary human purine nucleoside phosphorylase (HsPNP) immobilized enzyme reactor (IMER) for characterization and affinity screening studies of new inhibitors by frontal affinity chromatography coupled to mass spectrometry (FAC-MS). For this purpose two monolithic supports, a Chromolith Speed Rod (0.1mm I.D.×5cm) and a methacrylate-based monolithic epoxy polymeric capillary column (0.25mm I.D.×5cm) with epoxy reactive groups were considered and compared to an IMER previously developed using an open fused silica capillary. Each HsPNP-IMER was characterized in terms of catalytic activity using Inosine as standard substrate. Furthermore, they were also explored for affinity ranking experiments. Kd determination was carried out with the based fused silica HsPNP-IMER and the results are herein discussed. PMID:24630982

  14. Biosorption of metal contaminants using immobilized biomass: A laboratory study. Rept. of Investigations/1991

    SciTech Connect

    Jeffers, T.H.; Ferguson, C.R.; Bennett, P.G.

    1991-01-01

    The U.S. Bureau of Mines has developed porous beads containing immobilized biological materials for removing metal contaminants from waste waters. The beads, designated as BIO-FIX beads, are prepared by blending biomass, such as sphagnum peat moss or algae, into a polymer solution and spraying the mixture into water. Laboratory studies were conducted to determine bead sorption and elution characteristics. Batch and continuous tests demonstrated that BIO-FIX beads sorbed arsenic, cadmium, lead, and other toxic metals from acid mine drainage waters collected from several sites. Selectivity for heavy and toxic metal ions over calcium and magnesium was demonstrated. The beads exhibited excellent metal sorption and handling characteristics in stirred tanks, column contactors, and a low-maintenance passive system. The sorption process was reversible, and metal ions were eluted from the beads using dilute mineral acids. Cyclic tests indicated that the beads continued to extract metal ions after repeated loading-elution cycles.

  15. Immobilization of DNA at Glassy Ccarbon Electrodes: A Critical Study of Adsorbed Layer

    PubMed Central

    Pedano, M. L.; Rivas, G. A.

    2005-01-01

    In this work we present a critical study of the nucleic acid layer immobilized at glassy carbon electrodes. Different studies were performed in order to assess the nature of the interaction between DNA and the electrode surface. The adsorption and electrooxidation of DNA demonstrated to be highly dependent on the surface and nature of the glassy carbon electrode. The DNA layer immobilized at a freshly polished glassy carbon electrode was very stable even after applying highly negative potentials. The electron transfer of potassium ferricyanide, catechol and dopamine at glassy carbon surfaces modified with thin (obtained by adsorption under controlled potential conditions) and thick (obtained by casting the glassy carbon surface with highly concentrated DNA solutions) DNA layers was slower than that at the bare glassy carbon electrode, although this effect was dependent on the thickness of the layer and was not charge selective. Raman experiments showed an important decrease of the vibrational modes assigned to the nucleobases residues, suggesting a strong interaction of these residues with the electrode surface. The hybridization of oligo(dG)21 and oligo(dC)21 was evaluated from the guanine oxidation signal and the reduction of the redox indicator Co(phen)33+. In both cases the chronopotentiometric response indicated that the compromise of the bases in the interaction of DNA with the electrode surface is too strong, preventing further hybridization. In summary, glassy carbon is a useful electrode material to detect DNA in a direct and very sensitive way, but not to be used for the preparation of biorecognition layers by direct adsorption of the probe sequence on the electrode surface for detecting the hybridization event.

  16. Microorganism immobilization

    DOEpatents

    Compere, Alicia L.; Griffith, William L.

    1981-01-01

    Live metabolically active microorganisms are immobilized on a solid support by contacting particles of aggregate material with a water dispersible polyelectrolyte such as gelatin, crosslinking the polyelectrolyte by reacting it with a crosslinking agent such as glutaraldehyde to provide a crosslinked coating on the particles of aggregate material, contacting the coated particles with live microorganisms and incubating the microorganisms in contact with the crosslinked coating to provide a coating of metabolically active microorganisms. The immobilized microorganisms have continued growth and reproduction functions.

  17. A noble technique a using force-sensing resistor for immobilization-device quality assurance: A feasibility study

    NASA Astrophysics Data System (ADS)

    Cho, Min-Seok; Kim, Tae-Ho; Kang, Seong-Hee; Kim, Dong-Su; Kim, Kyeong-Hyeon; Shin, Dong-Seok; Noh, Yu-Yun; Koo, Hyun-Jae; Cheon, Geum Seong; Suh, Tae Suk; Kim, Siyong

    2016-03-01

    Many studies have reported that a patient can move even when an immobilization device is used. Researchers have developed an immobilization-device quality-assurance (QA) system that evaluates the validity of immobilization devices. The QA system consists of force-sensing-resistor (FSR) sensor units, an electric circuit, a signal conditioning device, and a control personal computer (PC) with in-house software. The QA system is designed to measure the force between an immobilization device and a patient's skin by using the FSR sensor unit. This preliminary study aimed to evaluate the feasibility of using the QA system in radiation-exposure situations. When the FSR sensor unit was irradiated with a computed tomography (CT) beam and a treatment beam from a linear accelerator (LINAC), the stability of the output signal, the image artifact on the CT image, and changing the variation on the patient's dose were tested. The results of this study demonstrate that this system is promising in that it performed within the error range (signal variation on CT beam < 0.30 kPa, root-mean-square error (RMSE) of the two CT images according to presence or absence of the FSR sensor unit < 15 HU, signal variation on the treatment beam < 0.15 kPa, and dose difference between the presence and the absence of the FSR sensor unit < 0.02%). Based on the obtained results, we will volunteer tests to investigate the clinical feasibility of the QA system.

  18. Study of bi-enzyme immobilization onto layered double hydroxides nanomaterials for histamine biosensor application.

    PubMed

    Baccar, Z M; Hidouri, S; Errachid, A; Sanchez, O Ruiz

    2011-10-01

    In this work, we present the development of a hybrid biomembrane based on the immobilization of diamine oxidase (DAO) into LDH thin films for histamine detection. The LDHs preselected as host matrixes are: hydrotalcites (Mg2Al(CO3)0.5(OH)6), lowaite (Mg4Fe(OH)10Cl) and hydrocalumite (Ca2Al(OH)6Cl). The immobilized probes were characterized by atomic force microscopy (AFM) and attenuated total reflection infrared spectroscopy (IR-ATR mode). The analysis of these results shows that the immobilization of DAO occurs with all type of selected LDH and is stable after a 7 day-immersion in phosphate buffer solution. The LDH incorporating magnesium or calcium divalent cations present high-quality surface topology for DAO immobilization and the ability to keep the enzyme in a well conformation for biogenic amines catabolism and histamine detection. PMID:22400262

  19. [Studies on immobilization of suspension cells of peltate yam (Dioscorea zingiberensis C.H. Wright)].

    PubMed

    Ren, J W; Bai, Y; Guo, Q Y; Zhang, R C

    1994-09-01

    The suspension cells of D. zingiberensis were immobilized with 3% sodium alginate, and then cultured in MS+2, 4-D1.0 + 6-BA 0.1 at 25 degrees C for a long period of time. The culture fluid free from cells was extracted and analyzed by TLC. The result showed that the immobilized cells could secrete the main component of D. zingiberensis--diosgenin, but not consecutively. PMID:7811362

  20. Plutonium Immobilization Project Binder Burnout and Sintering Studies (Milestone 6.6a)

    SciTech Connect

    Chandler, G.

    1999-10-28

    The Plutonium Immobilization Team has developed an integrated test program to understand and optimize the controlling variables for the sintering step of the plutonium immobilization process. Sintering is the key process step that controls the product minerology. It is expected that the sintering will be the limiting process step that controls the throughput of the production line. The goal of the current sintering test program is to better understand factors that affect the sintering process.

  1. Luminescence study of UO[sup 2+][sub 2] binding to immobilized datura innoxia biomaterial

    SciTech Connect

    Ke, Huei-Yang D.; Rayson, G.D. )

    1993-01-01

    The spectrally and temporally resolved UO[sup 2+][sub 2] fluorescence signals have been measured for solid samples of UO[sup 2+][sub 2]-Datura, UO[sup 2+][sub 2]-(immobilized Datura), and UO[sup 2+][sub 2]-(silicate polymer) at liquid nitrogen temperature. The binding capacity of UO[sup 2+][sub 2] to Datura innoxia cell material has been enhanced significantly at pH 5 and 6 when immobilized in a polysilicate matrix. New binding sites having a greater binding strength with a lower availability have been observed for the binding of UO[sup 2+][sub 2] after immobilization of the cultured biomaterial. However, chemical alteration of the cell material resulting from this immobilization process has not been observed. The chemical environment of the binding sites responsible for the binding of UO[sup 2+][sub 2] in immobilized and free D. innoxia cell material has been demonstrated to be different. This difference results from the immobilization of the cell material within a polysilicate matrix. 19 refs., 8 figs., 4 tabs.

  2. Covalent immobilization of pullulanase on alginate and study of its hydrolysis of pullulan.

    PubMed

    Ali, Ghina; Dulong, Virginie; Gasmi, Sarah N; Rihouey, Christophe; Picton, Luc; Le Cerf, Didier

    2015-01-01

    The immobilization of pullulanase from Klebsiella pneumoniae by grafting was investigated. Pullulanase was linked after activation of alginate via a covalent bond between the amine groups of the enzyme and the carboxylic acid groups of alginate. The immobilization yield was 60%. The activity of free pullulanase and immobilized pullulanase was followed by the quantification of reducing ends by colorimetric assay and the determination of the molar masses of the hydrolyzed pullulan by SEC/MALS/DRI. Compared to free pullulanase, the kinetics is largely slowed. The evolution of the weight average molar mass of pullulan leading to high production of shorter oligosaccharides during hydrolysis is not the same as that obtained with free enzyme. Immobilized pullulanase retained 75% and 30% of its initial activity after 24 h and 14 days of incubation at 60°C, respectively while free pullulanase lost its activity after 5 h of hydrolysis at the same temperature. The kinetic parameters of immobilized pullulanase were also investigated by isothermal titration calorimetry (ITC). The affinity of immobilized enzyme to its substrate was reduced compared to the free pullulanase due to steric hindrance and chemical links. PMID:25919860

  3. Immobilization of flavan-3-ols onto sensor chips to study their interactions with proteins and pectins by SPR

    NASA Astrophysics Data System (ADS)

    Watrelot, Aude A.; Tran, Dong Tien; Buffeteau, Thierry; Deffieux, Denis; Le Bourvellec, Carine; Quideau, Stéphane; Renard, Catherine M. G. C.

    2016-05-01

    Interactions between plant polyphenols and biomacromolecules such as proteins and pectins have been studied by several methods in solution (e.g. isothermal titration calorimetry, dynamic light scattering, nuclear magnetic resonance and spectrophotometry). Herein, these interactions were investigated in real time by Surface Plasmon Resonance (SPR) analysis after immobilization of flavan-3-ols onto a sensor chip surface. (-)-epicatechin, (+)-catechin and flavan-3-ol oligomers with an average degree of polymerization of 2 and 8 were chemically modified using N-(2-(tritylthio)ethyl)propiolamide in order to introduce a spacer unit onto the catecholic B ring. Modified flavan-3-ols were then immobilized onto a carboxymethylated dextran surface (CM5). Immobilization was validated and further verified by evaluating flavan-3-ol interaction with bovine serum albumin (BSA), poly-L-proline or commercial pectins. BSA was found to have a stronger association with monomeric flavan-3-ols than oligomers. SPR analysis of selected flavan-3-ols immobilized onto CM5 sensor chips showed a stronger association for citrus pectins than apple pectins, regardless of flavan-3-ol degree of polymerization.

  4. Biosorption of Cu(II) by immobilized microalgae using silica: kinetic, equilibrium, and thermodynamic study.

    PubMed

    Lee, Hongkyun; Shim, Eunjung; Yun, Hyun-Shik; Park, Young-Tae; Kim, Dohyeong; Ji, Min-Kyu; Kim, Chi-Kyung; Shin, Won-Sik; Choi, Jaeyoung

    2016-01-01

    Immobilized microalgae using silica (IMS) from Micractinium reisseri KGE33 was synthesized through a sol-gel reaction. Green algal waste biomass, the residue of M. reisseri KGE33 after oil extraction, was used as the biomaterial. The adsorption of Cu(II) on IMS was tested in batch experiments with varying algal doses, pH, contact times, initial Cu(II) concentrations, and temperatures. Three types of IMSs (IMS 14, 70, and 100) were synthesized according to different algal doses. The removal efficiency of Cu(II) in the aqueous phase was in the following order: IMS 14 (77.0%) < IMS 70 (83.3%) < IMS 100 (87.1%) at pH 5. The point of zero charge (PZC) value of IMS100 was 4.5, and the optimum pH for Cu(II) adsorption was 5. Equilibrium data were described using a Langmuir isotherm model. The Langmuir model maximum Cu(II) adsorption capacity (q m) increased with the algal dose in the following order: IMS 100 (1.710 mg g(-1)) > IMS 70 (1.548 mg g(-1)) > IMS 14 (1.282 mg g(-1)). The pseudo-second-order equation fitted the kinetics data well, and the value of the second-order rate constant increased with increasing algal dose. Gibbs free energies (ΔG°) were negative within the temperature range studied, which indicates that the adsorption process was spontaneous. The negative value of enthalpy (ΔH°) again indicates the exothermic nature of the adsorption process. In addition, SEM-energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared (FT-IR), and X-ray photoelectron spectroscopy (XPS) analyses of the IMS surface reveal that the algal biomass on IMS is the main site for Cu(II) binding. This study shows that immobilized microalgae using silica, a synthesized biosorbent, can be used as a cost-effective sorbent for Cu(II) removal from the aqueous phase. PMID:25953610

  5. Sonoenzymatic decolourization of an azo dye employing immobilized horse radish peroxidase (HRP): a mechanistic study.

    PubMed

    Malani, Ritesh S; Khanna, Swati; Moholkar, Vijayanand S

    2013-07-15

    For degradation of biorefractory pollutants, enzymatic treatments and sonochemical treatments have shown high potential. A combined technique of sono-enzymatic treatment is of special interest as it has shown enhancement effect than the individual techniques. This work has attempted to give a mechanistic insight into the interaction of sonochemical and enzymatic treatments using immobilized horseradish peroxidase (HRP) enzyme on the decolourization of acid red dye (an azo dye). In order to segregate the effect of ultrasound and cavitation, experiments were conducted at elevated static pressure. The kinetic parameters of HRP, viz. Vmax and Km were marginally affected by immobilization. There was a minor change in pH optima and temperature optima for immobilized HRP (6.5, 25°C) from free HRP (7.0, 20-25°C). Though the specific activity of free enzyme (0.272U/mg) was found to be higher than the immobilized enzyme (0.104U/mg), immobilized enzyme exhibited higher stability (up to 3 cycles) and degradation potential than free enzyme in all experiments. The results revealed that the coupling of sonication and enzymatic treatment at high pressure in presence of polyethylene glycol (PEG) yielded the highest decolourization of acid red (61.2%). However, the total decolourization achieved with combined technique was lesser than the sum of individual techniques, indicating negative synergy between the sonochemical and enzymatic techniques. PMID:23708258

  6. A comparative study of enzyme immobilization strategies for multi-walled carbon nanotube glucose biosensors

    NASA Astrophysics Data System (ADS)

    Shi, Jin; Claussen, Jonathan C.; McLamore, Eric S.; Haque, Aeraj ul; Jaroch, David; Diggs, Alfred R.; Calvo-Marzal, Percy; Rickus, Jenna L.; Porterfield, D. Marshall

    2011-09-01

    This work addresses the comparison of different strategies for improving biosensor performance using nanomaterials. Glucose biosensors based on commonly applied enzyme immobilization approaches, including sol-gel encapsulation approaches and glutaraldehyde cross-linking strategies, were studied in the presence and absence of multi-walled carbon nanotubes (MWNTs). Although direct comparison of design parameters such as linear range and sensitivity is intuitive, this comparison alone is not an accurate indicator of biosensor efficacy, due to the wide range of electrodes and nanomaterials available for use in current biosensor designs. We proposed a comparative protocol which considers both the active area available for transduction following nanomaterial deposition and the sensitivity. Based on the protocol, when no nanomaterials were involved, TEOS/GOx biosensors exhibited the highest efficacy, followed by BSA/GA/GOx and TMOS/GOx biosensors. A novel biosensor containing carboxylated MWNTs modified with glucose oxidase and an overlying TMOS layer demonstrated optimum efficacy in terms of enhanced current density (18.3 ± 0.5 µA mM - 1 cm - 2), linear range (0.0037-12 mM), detection limit (3.7 µM), coefficient of variation (2%), response time (less than 8 s), and stability/selectivity/reproducibility. H2O2 response tests demonstrated that the most possible reason for the performance enhancement was an increased enzyme loading. This design is an excellent platform for versatile biosensing applications.

  7. A comparative study of enzyme immobilization strategies for multi-walled carbon nanotube glucose biosensors.

    PubMed

    Shi, Jin; Claussen, Jonathan C; McLamore, Eric S; ul Haque, Aeraj; Jaroch, David; Diggs, Alfred R; Calvo-Marzal, Percy; Rickus, Jenna L; Porterfield, D Marshall

    2011-09-01

    This work addresses the comparison of different strategies for improving biosensor performance using nanomaterials. Glucose biosensors based on commonly applied enzyme immobilization approaches, including sol-gel encapsulation approaches and glutaraldehyde cross-linking strategies, were studied in the presence and absence of multi-walled carbon nanotubes (MWNTs). Although direct comparison of design parameters such as linear range and sensitivity is intuitive, this comparison alone is not an accurate indicator of biosensor efficacy, due to the wide range of electrodes and nanomaterials available for use in current biosensor designs. We proposed a comparative protocol which considers both the active area available for transduction following nanomaterial deposition and the sensitivity. Based on the protocol, when no nanomaterials were involved, TEOS/GOx biosensors exhibited the highest efficacy, followed by BSA/GA/GOx and TMOS/GOx biosensors. A novel biosensor containing carboxylated MWNTs modified with glucose oxidase and an overlying TMOS layer demonstrated optimum efficacy in terms of enhanced current density (18.3 ± 0.5 µA mM(-1) cm(-2)), linear range (0.0037-12 mM), detection limit (3.7 µM), coefficient of variation (2%), response time (less than 8 s), and stability/selectivity/reproducibility. H(2)O(2) response tests demonstrated that the most possible reason for the performance enhancement was an increased enzyme loading. This design is an excellent platform for versatile biosensing applications. PMID:21828892

  8. Biosorption of metal contaminants using immobilized biomass: Field studies. Report of Investigations/1993

    SciTech Connect

    Jeffers, T.H.; Bennett, P.G.; Corwin, R.R.

    1993-01-01

    The U.S. Bureau of Mines has developed porous beads containing immobilized biological materials such as sphagnum peat moss for extracting metal contaminants from waste waters. The beads, designated as BIO-FIX beads, have removed toxic metals from over 100 waters in laboratory tests. These waters include acid mine drainage (AMD) water from mining sites, metallurgical and chemical industry waste water, and contaminated ground water. Following the laboratory studies, cooperative field tests were conducted to evaluate the metal adsorption properties of the beads in column and low-maintenance circuits, determine bead stability in varied climatic situations, and demonstrate the beads' potential as a viable waste water treatment technique. Field results indicated that BIO-FIX beads readily adsorbed cadmium, lead, and other toxic metals from dilute waters; effluents frequently met drinking water standards and other discharge criteria. The beads exhibited excellent handling characteristics in both column and low-maintenance circuits, and continued to extract metal ions after repeated loading-elution cycles.

  9. Evaluation of enzyme immobilization methods for paper-based devices--A glucose oxidase study.

    PubMed

    Nery, Emilia Witkowska; Kubota, Lauro T

    2016-01-01

    Paper-based sensors gained almost explosive attention during the last few years. A large number of systems, often destined to resource limited settings is based on enzymatic reactions. Choice of an adequate immobilization method could significantly prolong the shelf-life of such sensors, especially in applications, where exposure to high temperatures during storage and transport is more than a threat. We are seeking to compare a variety of immobilization methods based on different phenomena (adsorption, entrapment in gel, microencapsulation, covalent linkage), with total of 33 methods tested. Glucose oxidase was used as a model enzyme. Enzymatic activity of immobilized samples was accompanied for a period of 24 weeks considering two sets of samples, one stored in 4 °C and other in ambient temperature. PMID:26498392

  10. Confocal Microscopy Studies of Trypsin Immobilization on Porous Glycidyl Methacrylate Beads.

    PubMed

    Malmsten; Xing; Ljunglöf

    1999-12-15

    The immobilization of trypsin on porous glycidyl methacrylate (GMA-GDMA) beads has been investigated. In particular, the distribution within the beads of trypsin and of dextran used for hydrophilizing the bead surface prior to protein immobilization was investigated with confocal microscopy. For the system investigated, the fluorescence intensity profiles obtained when using borate buffer as an ambient solution displayed a distinct minimum at the center of the beads, irrespective of the observation depth. However, by reduction of the refractive index difference between the solution and the beads through the addition of glucose to the aqueous solution, artifacts relating to optical length differences could be reduced. For both low molecular weight fluorescein isothiocyanate (FITC), FITC-labeled trypsin, and FITC-labeled dextran, an essentially homogeneous distribution throughout the beads was observed. This simple "contrast matching" method seems therefore to be an interesting tool when investigating the distribution of immobilized protein in porous chromatography media. Copyright 1999 Academic Press. PMID:10607463

  11. Enzymic interesterification of fats: Laboratory and pilot-scale studies with immobilized lipase from Rhizopus arrhizus.

    PubMed

    Wisdom, R A; Dunnill, P; Lilly, M D

    1987-06-01

    An immobilized lipase suitable for fat interesterification has been prepared by precipitation with acetone of a commercial lipase from Rhizopus arrhizus onto diatomaceous earth. As observed previously with a less active enzyme from Aspergillus sp., the interesterification activity was enhanced by addition of purified lipase or by high loadings of commercial enzyme. The interesterification activities reached maximum values in both cases. For immobilized preparations with purified enzyme, interesterification activity was also enhanced by the presence of a precoat of glutaraldehyde cross-linked commercial lipase. A 2.9-L column of immobilized lipase was used to interesterify batches of shea oleine (67 kg) and shea oil (40 kg). Little activity was lost processing shea oleine, but slow poisoning of the bed occurred when shea oil was fed to the column. PMID:18576561

  12. A kinetic study on the bioremediation of sodium cyanide and acetonitrile by free and immobilized cells of pseudomonas putida

    SciTech Connect

    Chapatwala, K.D.; Babu, G.R.V.; Armstead, E.R.

    1995-12-31

    Pseudomonas putida capable of utilizing organic nitrile (acetonitrile) and inorganic cyanide (sodium cyanide) as the sole source of carbon and nitrogen was isolated from contaminated industrial sites and waste water. The bacterium possesses nitrile aminohydrolase (EC 3.5.5.1) and amidase (EC 3.5.1.4), which are involved in the transformation of cyanides and nitrites into ammonia and CO{sub 2} through the formation of amide as an intermediate. Both of the enzymes have a high selectivity and affinity toward the {sup -}CN group. The rate of degradation of acetonitrile and sodium cyanide to ammonia and CO{sub 2} by the calcium-alginate immobilized cells of P. putida was studied. The rate of reaction during the biodegradation of acetonitrile and sodium cyanide, and the substrate- and product-dependent kinetics of these toxic compounds were studied using free and immobilized cells of P. putida and modeled using a simple Michaelis-Menten equation.

  13. Immobilization of DNA for affinity chromatography and drug-binding studies.

    PubMed Central

    Macdougall, A J; Brown, J R; Plumbridge, T W

    1980-01-01

    A method is described in which double-stranded DNA is alkylated with 4-bis-(2-chloroethyl)amino-L-phenylalanine and the product immobilized on an insoluble support via the primary amino group of the phenylalanine moiety. The DNA is hence irreversibly bound to the matrix by both strands at a limited number of points. PMID:7283977

  14. Physical and chemical immobilization of choline oxidase onto different porous solid supports: Adsorption studies.

    PubMed

    Passos, Marieta L C; Ribeiro, David S M; Santos, João L M; Saraiva, M Lúcia M F S

    2016-08-01

    This work carries out for the first time the comparison between the physical and chemical immobilization of choline oxidase onto aminated silica-based porous supports. The influence on the immobilization efficiency of concentration, pH, temperature and contact time between the support and choline oxidase, was evaluated. The immobilization efficiency was estimated taking into consideration the choline oxidase activity, which was assessed by using cadmium telluride (CdTe) quantum dots (QDs), obtained by hydrothermal synthesis, as photoluminescent probes. Hydrogen peroxide produced by enzyme activity was capable of quenching CdTe QDs photoluminescence. The magnitude of the PL quenching process was directly related with the enzyme activity. By comparing the chemical process with the physical adsorption, it was observed that the latter provided the highest choline oxidase immobilization. The equilibrium data were analyzed using Langmuir and Freundlich isotherms and kinetic data were fitted to the pseudo-first-order and pseudo-second-order models. Thermodynamic parameters, such as Gibbs free energy and entropy were also calculated. These results will certainly contribute to the development of new sensing schemes for choline, taking into account the growing demand for its quantification in biological samples. PMID:27241295

  15. The effect of cast immobilization on meniscal healing. An experimental study in the dog.

    PubMed

    Dowdy, P A; Miniaci, A; Arnoczky, S P; Fowler, P J; Boughner, D R

    1995-01-01

    A 1.5-cm longitudinal, full-thickness incision was made in the vascularized portion of the medial meniscus in 20 adult dogs and anatomically repaired. Postoperatively, the animals were either placed in a long leg cast (N = 9) or mobilized immediately (N = 11). The animals were sacrificed at 2 weeks (6 dogs), 4 weeks (6 dogs), or 10 weeks (8 dogs). Five medial menisci from the nonoperated side were used as controls. Collagen content was measured using a digital image analysis system, and the collagen percentage in the repair tissue in each postoperative treatment group was compared. In the 2-week and 4-week groups, there was no statistically significant difference in the percentage of collagen between those animals immobilized versus those that had early mobilization. The animals in the 10-week group that were mobilized had a significantly greater collagen percentage in the healing meniscal incision than those that were cast immobilized (44.6% +/- 10% versus 27.0% +/- 11%, P < 0.0001). There was no significant difference in the collagen percentages between the mobilized 10-week group and the contralateral control menisci group. All other menisci had a decreased collagen percentage compared with the controls. Prolonged immobilization decreases collagen formation in healing menisci. Thus, our results suggest that patients undergoing isolated meniscal repair either be immediately mobilized after surgery or immobilized for short periods only. PMID:8600741

  16. An Experimental Study of Sand Transport over an Immobile Gravel Substrate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of a stepwise addition of sand to an immobile gravel bed on the sand transport rate and configuration of the sand bed was investigated in a laboratory flume channel. Detailed measurements of sand transport rate, bed texture, and bed topography were collected for four different discharge...

  17. Immobilized purine nucleoside phosphorylase from Schistosoma mansoni for specific inhibition studies.

    PubMed

    de Moraes, Marcela Cristina; Cardoso, Carmen L; Cass, Quezia B

    2013-05-01

    The parasite Schistosoma mansoni (Sm) depends exclusively on the salvage pathway for its purine requirements. The enzyme purine nucleoside phosphorylase (PNP) is, therefore, a promising target for development of antischistosomal agents and an assay for screening of inhibitors. To enable this, immobilized SmPNP reactors were produced. By quantification of hypoxanthine by liquid chromatography, kinetic constants (K M) for the substrate inosine were determined for the free and immobilized enzyme as 110 ± 6.90 μmol L (-1) and 164 ± 13.4 μmol L (-1), respectively, indicating that immobilization did not affect enzyme activity. Furthermore, the enzyme retained 25 % of its activity after four months. Non-Michaelis kinetics for the phosphate substrate, and capacity for Pi-independent hydrolysis were also demonstrated, despite the low rate of enzymatic catalysis. Use of an SmPNP immobilized enzyme reactor (IMER) for inhibitor-screening assays was demonstrated with a small library of 9-deazaguanine analogues. The method had high selectivity and specificity compared with screening by use of the free enzyme by the Kalckar method, and furnished results without the need for verification of the absence of false positives. PMID:23535739

  18. Study on contraction and relaxation of experimentally denervated and immobilized muscles: Comparison with dystrophic muscles

    NASA Technical Reports Server (NTRS)

    Takamori, M.; Tsujihata, M.; Mori, M.; Hazama, R.; Ide, Y.

    1980-01-01

    The contraction-relaxation mechanism of experimentally denervated and immobilized muscles of the rabbit is examined. Results are compared with those of human dystrophic muscles, in order to elucidate the role and extent of the neurotrophic factor, and the role played by the intrinsic activity of muscle in connection with pathogenesis and pathophysiology of this disease.

  19. Cervical Spine Immobilization in Sports Related Injuries: Review of Current Guidelines and a Case Study of an Injured Athlete

    PubMed Central

    Bhamra, JS; Morar, Y; Khan, WS; Deep, K; Hammer, A

    2012-01-01

    Cervical spine immobilization is an essential component of the ATLS® system. Inadequate training in the management of trauma calls and failure of early recognition can have disastrous consequences. Pre-hospital personnel are routinely involved more in the assessment and stabilization of patients in comparison to other health care professionals. This case study and review highlights the importance of early recognition, assessment and correct stabilization of cervical spine injuries both in the field and during the initial assessment in hospital. Inadequate assessment, immobilization and lack of standard guidelines on the management of suspected cervical spine trauma can result in secondary injury. Regular assessment and training of pre-hospital and medical personnel is essential to the proper management of these potentially devastating injuries. PMID:23248726

  20. Comparative studies of Remazol Brillant Blue removal by immobilized organisms; investigation of metabolites by GC/MS and FTIR spectrometry.

    PubMed

    Akdogan, Hatice Ardag; Topuz, Merve Canpolat

    2015-01-01

    Reactive dyes are important chemical pollutants from textile industries. Treatment of effluents from dye-based industries poses a major problem, and biotreatment with white rot fungi seems to be a viable option. The biological treatment of synthetic dyes at a low cost and in the shortest possible time is used especially in dye and textile industries and leads to pollution in the wastewater dumped into the environment by these industries. For this study, decolorization of the recalcitrant dye Remazol Brilliant Blue R by immobilized Pleurotus ostreatus and Coprinus plicatilis was investigated. This dye was removed 100% (dye concentration: 10.0 mg/L) by both immobilized organisms. Extracellular ligninolytic enzyme activities were also measured during the decolorization. There was an attempt to identify metabolites with FTIR spectrometry and GC/MS at the end of the decolorization. These results indicated that the samples did not include any detectable metabolite. PMID:25905752

  1. Solvent Stability Study with Thermodynamic Analysis and Superior Biocatalytic Activity of Burkholderia cepacia Lipase Immobilized on Biocompatible Hybrid Matrix of Poly(vinyl alcohol) and Hypromellose.

    PubMed

    Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2014-12-26

    In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (K(D)) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the K(D)-value was found to be less in cyclohexane (0.843 × 10(-3)) as compared to acetone (1.997 × 10(-3)), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (E(a)) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic efficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH(⧧)), entropy (ΔS(⧧)) and Gibb's free energy (ΔG(⧧)) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time. PMID:25474503

  2. PRELIMINARY STUDY OF CERAMICS FOR IMMOBILIZATION OF ADVANCED FUEL CYCLE REPROCESSING WASTES

    SciTech Connect

    Fox, K.; Billings, A.; Brinkman, K.; Marra, J.

    2010-09-22

    The Savannah River National Laboratory (SRNL) developed a series of ceramic waste forms for the immobilization of Cesium/Lanthanide (CS/LN) and Cesium/Lanthanide/Transition Metal (CS/LN/TM) waste streams anticipated to result from nuclear fuel reprocessing. Simple raw materials, including Al{sub 2}O{sub 3}, CaO, and TiO{sub 2} were combined with simulated waste components to produce multiphase ceramics containing hollandite-type phases, perovskites (particularly BaTiO{sub 3}), pyrochlores, zirconolite, and other minor metal titanate phases. Identification of excess Al{sub 2}O{sub 3} via X-ray Diffraction (XRD) and Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) in the first series of compositions led to a Phase II study, with significantly reduced Al{sub 2}O{sub 3} concentrations and increased waste loadings. Three fabrication methodologies were used, including melting and crystallizing, pressing and sintering, and Spark Plasma Sintering (SPS), with the intent of studying phase evolution under various sintering conditions. XRD and SEM/EDS results showed that the partitioning of the waste elements in the sintered materials was very similar, despite varying stoichiometry of the phases formed. The Phase II compositions generally contained a reduced amount of unreacted Al{sub 2}O{sub 3} as identified by XRD, and had phase assemblages that were closer to the initial targets. Chemical composition measurements showed no significant issues with meeting the target compositions. However, volatilization of Cs and Mo was identified, particularly during melting, since sintering of the pressed pellets and SPS were performed at lower temperatures. Partitioning of some of the waste components was difficult to determine via XRD. SEM/EDS mapping showed that those elements, which were generally present in small concentrations, were well distributed throughout the waste forms. Initial studies of radiation damage tolerance using ion beam irradiation at Los

  3. Study of Immobilization Procedure on Silver Nanolayers and Detection of Estrone with Diverged Beam Surface Plasmon Resonance (SPR) Imaging

    PubMed Central

    Karabchevsky, Alina; Tsapovsky, Lev; Marks, Robert S.; Abdulhalim, Ibrahim

    2013-01-01

    An immobilization protocol was developed to attach receptors on smooth silver thin films. Dense and packed 11-mercaptoundecanoic acid (11-MUA) was used to avoid uncontrolled sulfidization and harmful oxidation of silver nanolayers. N,N'-dicyclohexylcarbodiimide (DCC) and N-hydroxysuccinimide (NHS) were added to make the silver surfaces reactive. A comparative study was carried out with different immersion times of silver samples in 11-MUA solutions with different concentrations to find the optimum conditions for immobilization. The signals, during each step of the protocol, were analyzed with a refractometer based on the surface plasmon resonance (SPR) effect and luminescence techniques. Molecular interactions at the surfaces between the probe and target at the surface nanolayer shift the SPR signal, thus indicating the presence of the substance. To demonstrate specific biosensing, rabbit anti-estrone polyclonal immunoglobulin G (IgG) antibody was immobilized through a linker on 47 nm silver layer deposited on SF11 glass. At the final stage, the representative endocrine disruptor—estrone—was attached and detected in deionized water with a diverging beam SPR imaging sensor. PMID:25587405

  4. Comparative study of olive oil mill wastewater treatment using free and immobilized Coriolopsis polyzona and Pycnoporus coccineus.

    PubMed

    Neifar, Mohamed; Jaouani, Atef; Martínez, María Jesús; Penninckx, Michel J

    2012-10-01

    The efficiency of the two white-rot fungi Pycnoporus coccineus and Coriolopsis polyzona in the Olive Oil Mill Wastewater (OOMW) treatment was investigated. Both fungi were active in the decolourisation and COD removal of OOMW at 50 g/L COD, but only the first fungus remains effective on the crude effluent (COD=100 g/L). Moreover P. coccineus was less affected by oxygen supplementation and exhibited a high tolerance to agitation in comparison to C. polyzona. However, it required a nitrogen supplementation to obtain faster and higher COD removal. To overcome the negative effect of agitation on fungi growth and efficiency, immobilisation of C. polyzona and P. coccineus in polyurethane foam was applied. The immobilized system showed better COD decreases during three consecutive batches without remarkable loss of performances. The results obtained in this study suggested that immobilized C. polyzona and especially immobilized P. coccineus might be applicable to a large scale for the removal colour and COD of OOMW. PMID:23124741

  5. Uranium Immobilization through Fe(II) bio-oxidation: A Column study

    SciTech Connect

    Coates, John D.

    2009-09-14

    Current research on the bioremediation of heavy metals and radionuclides is focused on the ability of reducing organisms to use these metals as alternative electron acceptors in the absence of oxygen and thus precipitate them out of solution. However, many aspects of this proposed scheme need to be resolved, not the least of which is the time frame of the treatment process. Once treatment is complete and the electron donor addition is halted, the system will ultimately revert back to an oxic state and potentially result in the abiotic reoxidation and remobilization of the immobilized metals. In addition, the possibility exists that the presence of more electropositive electron acceptors such as nitrate or oxygen will also stimulate the biological oxidation and remobilization of these contaminants. The selective nitrate-dependent biooxidation of added Fe(II) may offer an effective means of “capping off” and completing the attenuation of these contaminants in a reducing environment making the contaminants less accessible to abiotic and biotic reactions and allowing the system to naturally revert to an oxic state. Our previous DOE-NABIR funded studies demonstrated that radionuclides such as uranium and cobalt are rapidly removed from solution during the biogenic formation of Fe(III)-oxides. In the case of uranium, X-ray spectroscopy analysis indicated that the uranium was in the hexavalent form (normally soluble) and was bound to the precipitated Fe(III)-oxides thus demonstrating the bioremediative potential of this process. We also demonstrated that nitrate-dependent Fe(II)- oxidizing bacteria are prevalent in the sediment and groundwater samples collected from sites 1 and 2 and the background site of the NABIR FRC in Oakridge, TN. However, all of these studies were performed in batch experiments in the laboratory with pure cultures and although a significant amount was learned about the microbiology of nitrate-dependent bio-oxidation of Fe(II), the effects of

  6. Studies on acetone powder and purified rhus laccase immobilized on zirconium chloride for oxidation of phenols.

    PubMed

    Lu, Rong; Miyakoshi, Tetsuo

    2012-01-01

    Rhus laccase was isolated and purified from acetone powder obtained from the exudates of Chinese lacquer trees (Rhus vernicifera) from the Jianshi region, Hubei province of China. There are two blue bands appearing on CM-sephadex C-50 chromatography column, and each band corresponding to Rhus laccase 1 and 2, the former being the major constituent, and each had an average molecular weight of approximately 110 kDa. The purified and crude Rhus laccases were immobilized on zirconium chloride in ammonium chloride solution, and the kinetic properties of free and immobilized Rhus laccase, such as activity, molecular weight, optimum pH, and thermostability, were examined. In addition, the behaviors on catalytic oxidation of phenols also were conducted. PMID:22545205

  7. Immobilized tubular fermentor

    SciTech Connect

    Gencer, M.A.; Mutharasan, R.

    1983-09-01

    In this article, a mathematical model describing the kinetics of ethanol fermentation in a whole cell immobilized tubular fermentor is proposed. Experimental results show reasonable agreement with the proposed model. A procedure for treating the fermentation data for determining the ethanol inhibition constants k1 and k2 is described. The ethanol productivity of the immobilized cell fermentor is compared with those of traditional fermentors. Experimental studies indicate that with Saccharomyces cerevisiae (NRRL Y132) culture, ethanol productivity in the range 21.2-83.7 g ethanol/L/h at ethanol concentration of 76-60 g/L can be achieved. This is comparable to or higher than those reported in the literature for yeast. The product yield factor of 0.5 g ethanol/g glucose was obtained. The immobilized cell fermentor does not show washout at dilution rates of 7/h and shows good stability over a 650-h operating period.

  8. Study on Different Molecular Weights of Chitosan as an Immobilization Matrix for a Glucose Biosensor

    PubMed Central

    Ang, Lee Fung; Por, Lip Yee; Yam, Mun Fei

    2013-01-01

    Two chitosan samples (medium molecular weight (MMCHI) and low molecular weight (LMCHI)) were investigated as an enzyme immobilization matrix for the fabrication of a glucose biosensor. Chitosan membranes prepared from acetic acid were flexible, transparent, smooth and quick-drying. The FTIR spectra showed the existence of intermolecular interactions between chitosan and glucose oxidase (GOD). Higher catalytic activities were observed on for GOD-MMCHI than GOD-LMCHI and for those crosslinked with glutaraldehyde than using the adsorption technique. Enzyme loading greater than 0.6 mg decreased the activity. Under optimum conditions (pH 6.0, 35°C and applied potential of 0.6 V) response times of 85 s and 65 s were observed for medium molecular weight chitosan glucose biosensor (GOD-MMCHI/PT) and low molecular weight chitosan glucose biosensor (GOD-LMCHI/PT), respectively. The apparent Michaelis-Menten constant () was found to be 12.737 mM for GOD-MMCHI/PT and 17.692 mM for GOD-LMCHI/PT. This indicated that GOD-MMCHI/PT had greater affinity for the enzyme. Moreover, GOD-MMCHI/PT showed higher sensitivity (52.3666 nA/mM glucose) when compared with GOD-LMCHI/PT (9.8579 nA/mM glucose) at S/N>3. Better repeatability and reproducibility were achieved with GOD-MMCHI/PT than GOD-LMCHI/PT regarding glucose measurement. GOD-MMCHI/PT was found to give the highest enzymatic activity among the electrodes under investigation. The extent of interference encountered by GOD-MMCHI/PT and GOD-LMCHI/PT was not significantly different. Although the Nafion coated biosensor significantly reduced the signal due to the interferents under study, it also significantly reduced the response to glucose. The performance of the biosensors in the determination of glucose in rat serum was evaluated. Comparatively better accuracy and recovery results were obtained for GOD-MMCHI/PT. Hence, GOD-MMCHI/PT showed a better performance when compared with GOD-LMCHI/PT. In conclusion, chitosan membranes shave

  9. Integrated immobilized cell reactor-adsorption system for beta-cyclodextrin production: a model study using PVA-cryogel entrapped Bacillus agaradhaerens cells.

    PubMed

    Martins, Rita F; Plieva, Fatima M; Santos, Ana; Hatti-Kaul, Rajni

    2003-09-01

    Production of cyclodextrins (CDs) by immobilized cells of the alkaliphilic Bacillus agaradhaerens LS-3C with integrated product recovery was studied. The microorganism was entrapped in polyvinyl alcohol-cryogel beads and used as a convenient source of immobilized cyclodextrin glycosyltransferase (CGTase). On activation by incubation in the cultivation medium containing 1% (w/v) starch, the entrapped cells multiplied and secreted CGTase with an activity of 2-3 mg beta-cyclodextrin h(-1) g(-1) beads. The immobilized biocatalyst exhibited maximum activity at pH 9 and 50 degrees C, and formed cyclodextrins comprising 92-94% beta-CD and remaining alpha-CD. The cyclodextrin product from the immobilized cell bioreactor was continuously recovered by adsorption to Amberlite XAD-4 in a recycle batch mode. The product adsorption was facilitated at low temperature while hot water was used for elution. PMID:14571979

  10. Sulfur immobilization and lithium storage on defective graphene: A first-principles study

    SciTech Connect

    Zhao, Wen; Chen, Pengcheng; Tang, Peizhe; Wu, Jian; Duan, Wenhui E-mail: dwh@phys.tsinghua.edu.cn; Li, Yuanchang E-mail: dwh@phys.tsinghua.edu.cn

    2014-01-27

    Motivated by the recent progresses and remaining technical challenges in Li-S battery, we employ defective graphene as a prototype cathode framework to illustrate how battery performance is influenced by the mesoporous carbon materials. We show that the immobilization of S unavoidably sacrifices its ability to further interact with Li, which leads to an enhanced cycle life but a decreased capacity. Based on our calculated results, we suggest a suitable S binding-energy range of ∼4–5 eV to balance the battery stability and capability under thermodynamic equilibrium conditions. Our results may promote the understanding and architecture design of Li-S battery.

  11. Formulation Study on Immobilization of Spent Ion Exchange Resins in Polymer Cements

    SciTech Connect

    Lili Xia; Meiqiong Lin; Bao Liangjin

    2006-07-01

    Applying normal design and correlative computer software, a new matrix material and an excellent waste formulation were developed. Based on the theory calculations and normal design in this paper, using polymer complex cement as immobilization matrix that mixed with simulating spent ion exchange resin a new waste formulation was carried out. The characterization of solidified waste had been done after 28 days curing. The results conformed to the treatment of the waste about the requests of the national standard [GB14569-93-1]. Leach index of the solidified waste was excellent. An optimized formulation was recommended. (authors)

  12. Sulfur immobilization and lithium storage on defective graphene: A first-principles study

    NASA Astrophysics Data System (ADS)

    Zhao, Wen; Chen, Pengcheng; Tang, Peizhe; Li, Yuanchang; Wu, Jian; Duan, Wenhui

    2014-01-01

    Motivated by the recent progresses and remaining technical challenges in Li-S battery, we employ defective graphene as a prototype cathode framework to illustrate how battery performance is influenced by the mesoporous carbon materials. We show that the immobilization of S unavoidably sacrifices its ability to further interact with Li, which leads to an enhanced cycle life but a decreased capacity. Based on our calculated results, we suggest a suitable S binding-energy range of ˜4-5 eV to balance the battery stability and capability under thermodynamic equilibrium conditions. Our results may promote the understanding and architecture design of Li-S battery.

  13. Mimetic biomembrane-AuNPs-graphene hybrid as matrix for enzyme immobilization and bioelectrocatalysis study.

    PubMed

    Wang, Tianshu; Liu, Jiyang; Ren, Jiangtao; Wang, Jin; Wang, Erkang

    2015-10-01

    A hybrid composite constructed of phospholipids bilayer membrane, gold nanoparticles and graphene was prepared and used as matrices for microperoxidase-11 (MP11) immobilization. The direct electrochemistry and corresponding bioelectrocatalysis of the enzyme electrode was further investigated. Phospholipid bilayer membrane protected gold nanoparticles (AuNPs) were assembled on polyelectrolyte functionalized graphene sheets through electrostatic attraction to form a hybrid bionanocomposite. Owing to the biocompatible microenvironment provided by the mimetic biomembrane, microperoxidase-11 entrapped in this matrix well retained its native structure and exhibited high bioactivity. Moreover, the AuNPs-graphene assemblies could efficiently promote the direct electron transfer between the immobilized MP11 and the substrate electrode. The as-prepared enzyme electrode presented good direct electrochemistry and electrocatalytic responses to the reduction of hydrogen peroxide (H2O2). The resulting H2O2 biosensor showed a wide linear range (2.0×10(-5)-2.8×10(-4) M), a low detection limit (2.6×10(-6) M), good reproducibility and stability. Furthermore, this sensor was used for real-time detection of H2O2 dynamically released from the tumor cells MCF-7 in response to a pro-inflammatory stimulant. PMID:26078181

  14. A comparative clinical study of three different dosages of intramuscular midazolam-medetomidine-ketamine immobilization in cats.

    PubMed

    Ebner, J; Wehr, U; Busch, R; Erhardt, W; Henke, J

    2007-10-01

    A low dose of midazolam-medetomidine-ketamine (MMK) combination was evaluated in three increasing dosages. Each of the 18 cats was randomly allocated for several times to one of four groups. Five minutes after premedication with intramuscular (IM) 0.04 mg/kg atropine, group A (n = 43), B (n = 40) and C (n = 28) all were anaesthetized with 0.5 mg/kg midazolam, combined with 10, 20 or 30 microg/kg medetomidine, and 1.0, 2.0 or 3.0 mg/kg ketamine, respectively, IM in one syringe. Group D (n = 11) received the established combination of 50 microg/kg medetomidine and 10.0 mg/kg ketamine for comparison. Because this study was in cooperation with a project on dental prophylaxis, cats had to be immobilized for approximately 1 h. Therefore, anaesthesia was prolonged with propofol to effect, if necessary. Duration of MMK anaesthesia was between 30 +/- 15, 45 +/- 19 and 68 +/- 28 min in groups A, B and C respectively. A significant decrease of respiratory rate was observed with increasing dosage, but venous carbon dioxide (pCO(2)) and pH values in combination with arterial oxygen saturation (SpO(2)) values were not alarming. The diastolic blood pressure particularly showed an increase. MMK combination A showed the best cardiovascular results, but it cannot be recommended due to disadvantages like a long induction time sometimes accompanied by excitations and the short duration of surgical immobilization. Dosage C in contrast had fewer side effects but less favourable cardiovascular results and a longer recovery period. However, either dosage B or C was suitable as a repeatable IM immobilization method for non-invasive procedures in healthy cats. PMID:17877583

  15. Si-F complexing in aqueous fluids: experimental study and implications for transport of immobile elements

    NASA Astrophysics Data System (ADS)

    Dolejš, David

    2014-05-01

    Intepretation of fluid-mineral interaction mechanisms and hydrothermal fluxes requires knowledge of predominant solubility and speciation reactions and their thermodynamic properties. Fluorine represents a hard electron donor, capable of complexing and transporting high-field strength elements, which are traditionally considered to be immobile. Reactions responsible for element mobility have general form MOx + y HF (aq) + x - y H2O = M(OH)2x-yFy (aq), and their extent and transport efficiency relies on hydrogen fluoride activity. In natural fluids, a[HF] is controlled by various fluorination equilibria including neutralization of silicates with consequent formation of silicohydroxyfluoride complexes. Quartz solubility in HF-H2O fluids was experimentally determined at 400-800 oC and 100-200 MPa using rapid-quench cold-seal pressure vessels and the mineral weight-loss method. Quartz solubility significantly increases in the presence of hydrogen fluoride: at 400 oC and 100 MPa, dissolved SiO2 ranges from 0.18 wt. % in pure H2O to 12.2 wt. % at 8.3 wt. % F in the fluid, whereas at 800 oC and 200 MPa it rises from 1.51 wt. % in pure H2O to 15.3 wt. % at 8.0 wt. % F in the fluid. The isobaric solubilities of quartz appear to be temperature-independent, i.e., effects of temperature vs. fluid density on the solubility are counteracting. The experimental data are described by the density model: log m[SiO2] = a + blog ρ + clog m[F] + dT , where a = -1.049 mol kg-1, b = 0.816 mol cm-3, c = 0.802 and d = 1.256 · 10-3 mol kg-1 K-1. Solubility isotherms have similar d(log m[SiO2])/d(log m[F]) slopes over the entire range of conditions indicating that Si(OH)2F2 is the major aqueous species. Several factors promote breakdown of silicohydroxyfluoride complexes and precipitation of silica solute: (i) decreasing temperature and pressure, i.e., fluid ascent and cooling and/or (ii) neutralization and increase in the alkali/H ratio of fluids during alteration reactions or removal of

  16. Calcitonin treatment of immobilization osteoporosis in rats.

    PubMed

    Tuukkanen, J; Jalovaara, P; Väänänen, K

    1991-01-01

    We studied changes in bone mass induced by immobilization and the ability of salmon calcitonin to inhibit immobilization osteoporosis in rat. The bone mass of the immobilized hind leg of rat was compared with the contralateral non-treated leg. Neurectomy and cast immobilization reduced the bone mineral mass to an equal extent. However, the dose-response of calcitonin was different with these immobilization techniques. Calcitonin 15 IU kg-1 administered once daily reduced bone ash weight difference significantly after 2 weeks' neurectomy (P less than 0.001). This had no significant effect on the bone loss induced by cast immobilization, but the dose had to be delivered as two injections given every 12 h. Two weeks' immobilization decreased the incorporation of 45Ca into bones. Calcitonin could not prevent this. However, calcitonin tended to inhibit the overall incorporation of 45Ca into bones in immobilized rats but yet had no effect on 45Ca incorporation in non-immobilized rats. Immobilization decreased serum alkaline phosphatase activity in cast-immobilized animals. Neurectomy did not change serum alkaline phosphatase activity from a sham operation level. The tartrate-resistant acid phosphatase to total acid phosphatase ratio in the serum increased significantly in neurectomized rats and in cast-immobilized calcitonin-treated rats. PMID:2053438

  17. Treatment of textile effluent in a developed phytoreactor with immobilized bacterial augmentation and subsequent toxicity studies on Etheostoma olmstedi fish.

    PubMed

    Watharkar, Anuprita D; Khandare, Rahul V; Waghmare, Pankajkumar R; Jagadale, Ashwini D; Govindwar, Sanjay P; Jadhav, Jyoti P

    2015-01-01

    A static hydroponic bioreactor using nursery grown plants of Pogonatherum crinitum along with immobilized Bacillus pumilus cells was developed for the treatment of textile wastewater. Independent reactors with plants and immobilized cells were also kept for performance and efficacy evaluation. The effluent samples characterized before and after their treatment showed that the plant-bacterial consortium reactor was more efficient than those of individual plant and bacterium reactors. COD, BOD, ADMI, conductivity, turbidity, TDS and TSS of the textile effluent was found to be reduced by 78, 70, 93, 4, 90, 13 and 70% respectively within 12 d by the consortial set. HPTLC analysis revealed the transformation of the textile effluent to new products. The phytotoxicity study on Phaeseolus mungo and Sorghum vulgare seeds showed reduced toxicity of treated effluents. The animal toxicity study performed on Etheostoma olmstedi fishes showed the toxic nature of untreated effluent giving extreme stress to fishes leading to death. Histology of fish gills exposed to treated effluent was found to be less affected. The oxidative stress related enzymes like superoxide dismutase and catalase were found to show decreased activities and less lipid peroxidation in fishes exposed to treated effluent. PMID:25464312

  18. Study of concentration of HPV DNA probe immobilization for cervical cancer detection based IDE biosensor

    NASA Astrophysics Data System (ADS)

    Roshila, M. L.; Hashim, U.; Azizah, N.

    2016-07-01

    This paper mainly illustrates regarding the detection process of Human Papillomavirus (HPV) DNA probe. HPV is the most common virus that infected to human by a sexually transmitted virus. The most common high-risk HPV are 16 and 18. Interdigitated electrode (IDE) device used as based of Titanium Dioxide (TiO2) acts as inorganic surface, where by using APTES as a linker between inorganic surface and organic surface. A strategy of rapid and sensitive for the HPV detection was proposed by integrating simple DNA extraction with a gene of DNA. The extraction of the gene of DNA will make an efficiency of the detection process. It will depend on the sequence of the capture probes and the way to support their attached. The fabrication, surface modification, immobilization and hybridization processes are characterized by current voltage (I-V) measurement by using KEITHLEY 6487. This strategy will perform a good sensitivity of HPV detection.

  19. A density functional theory study of arsenic immobilization by the Al(iii)-modified zeolite clinoptilolite.

    PubMed

    Awuah, Joel B; Dzade, Nelson Y; Tia, Richard; Adei, Evans; Kwakye-Awuah, Bright; Richard A Catlow, C; de Leeuw, Nora H

    2016-04-20

    We present density functional theory calculations of the adsorption of arsenic acid (AsO(OH)3) and arsenous acid (As(OH)3) on the Al(iii)-modified natural zeolite clinoptilolite under anhydrous and hydrated conditions. From our calculated adsorption energies, we show that adsorption of both arsenic species is favorable (associative and exothermic) under anhydrous conditions. When the zeolite is hydrated, adsorption is less favourable, with the water molecules causing dissociation of the arsenic complexes, although exothermic adsorption is still observed for some sites. The strength of interaction of the arsenic complexes is shown to depend sensitively on the Si/Al ratio in the Al(iii)-modified clinoptilolite, which decreases as the Si/Al ratio increases. The calculated large adsorption energies indicate the potential of Al(iii)-modified clinoptilolite for arsenic immobilization. PMID:27052997

  20. Macrocyclic receptors immobilized to monodisperse porous polymer particles by chemical grafting and physical impregnation for strontium capture: a comparative study.

    PubMed

    Song, Yang; Du, Yi; Lv, Dachao; Ye, Gang; Wang, Jianchen

    2014-06-15

    Separation of strontium is of great significance for radioactive waste treatment and environmental remediation after nuclear accidents. In this work, a novel class of adsorbent (Crown-g-MPPPs) was synthesized by chemical grafting a macrocyclic ether receptor to monodisperse porous polymer particles (MPPPs) for strontium adsorption. Meanwhile, a counterpart material (Crown@MPPPs) with the receptor molecules immobilized to the MPPPs substrate by physical impregnation was prepared. To investigate how the immobilization manner and distribution of the receptors influence the adsorption ability, a comparative study on the adsorption behaviour of the two materials towards Sr(II) in HNO3 media was accomplished. Due to the shorter diffusion path and covalently-bonded structure, Crown-g-MPPPs showed faster adsorption kinetics and better stability for cycle use. While Crown@MPPPs had the advantages of facile synthesis and higher adsorption capacity, owing to the absence of conformational constraint to form complexation with Sr(II). Kinetic functions (Lagergren pseudo-first-order/pseudo-second-order functions) and adsorption isotherm models (Langmuir/Freundlich models) were used to fit the experimental data and examine the adsorption mechanism. On this basis, a chromatographic process was proposed by using Crown@MPPPs for an effective separation of Sr(II) (91%) in simulated high level liquid waste (HLLW). PMID:24794813

  1. Bio-functionalization of electro-synthesized polypyrrole surface by heme enzyme using a mixture of Nafion and glutaraldehyde as synergetic immobilization matrix: Conformational characterization and electrocatalytic studies

    NASA Astrophysics Data System (ADS)

    ElKaoutit, Mohammed; Naranjo-Rodriguez, Ignacio; Domínguez, Manuel; Hidalgo-Hidalgo-de-Cisneros, José Luis

    2011-10-01

    Use of a mixture of Nafion and glutaraldehyde as new immobilization matrix was described. The percentage of Nafion was optimized to prevent denaturation of horseradish peroxidase enzyme after its crosslinkage with glutaraldehyde on electro-synthesized polypyrrole surface. Topographic study by Atomic Force Microscopy (AFM) shows that the enzyme seems to have been introduced inside the ionic cluster of Nafion. The characterization of the resulting bio-interfaces by UV-vis and FT-IR shows that the intra-crosslinkage phenomena caused by the use of glutaraldehyde can be eliminated by the optimization of the concentration of Nafion additive. The secondary structure contents of native and immobilized enzyme were analyzed by a Gaussian curve fitting of the respective FT-IR spectra in the amide I region. Immobilized enzyme presented notable increasing percentages of globular and short helical structure compared with native enzyme. This indicates that immobilized enzyme was folded which is in accordance with AFM studies and supports the enzyme entrance inside ionic clutter of Nafion. Thanks to synergic effects of the polypyrrole conducting polymer and the perfluorosulfonic acid polymer Nafion, HRP enzyme was immobilized in its "native" state, the resulting biosensor was able to sense peroxide without any chemical mediator and can be categorized as third generation.

  2. Covalent immobilization of redox enzyme on electrospun nonwoven poly(acrylonitrile-co-acrylic acid) nanofiber mesh filled with carbon nanotubes: a comprehensive study.

    PubMed

    Wang, Zhen-Gang; Ke, Bei-Bei; Xu, Zhi-Kang

    2007-07-01

    In this work, novel conductive composite nanofiber mesh possessing reactive groups was electrospun from solutions containing poly(acrylonitrile-co-acrylic acid) (PANCAA) and multi-walled carbon nanotubes (MWCNTs) for redoxase immobilization, assuming that the incorporated MWCNTs could behave as electrons transferor during enzyme catalysis. The covalent immobilization of catalase from bovine liver on the neat PANCAA nanofiber mesh or the composite one was processed in the presence of EDC/NHS. Results indicated that both the amount and activity retention of bound catalase on the composite nanofiber mesh were higher than those on the neat PANCAA nanofiber mesh, and the activity increased up to 42%. Kinetic parameters, K(m) and V(max), for the catalases immobilized on the composite nanofiber mesh were lower and higher than those on the neat one, respectively. This enhanced activity might be ascribed to either promoted electron transfer through charge-transfer complexes and the pi system of carbon nanotubes or rendered biocompatibility by modified MWCNTs. Furthermore, the immobilized catalases revealed much more stability after MWCNTs were incorporated into the polymer nanofiber mesh. However, there was no significant difference in optimum pH value and temperature, thermal stability and operational stability between these two immobilized preparations, while the two ones appeared more advantageous than the free in these properties. The effect of MWCNTs incorporation on another redox enzyme, peroxidase, was also studied and it was found that the activity increased by 68% in comparison of composite one with neat preparation. PMID:17171660

  3. Kinetic study of anaerobic digestion of fruit-processing wastewater in immobilized-cell bioreactors.

    PubMed

    Borja, R; Banks, C J

    1994-08-01

    The kinetics of the anaerobic digestion of a fruit-processing wastewater [chemical oxygen demand (COD) = 5.1 g/l] were investigated. Laboratory experiments were carried out in bioreactors containing supports of different chemical composition and features, namely bentonite and zeolite (aluminum silicates), sepiolite and saponite (magnesium silicates) and polyurethane foam, to which the microorganisms responsible for the process adhered. The influence of the support medium on the kinetics was compared with a control digester with suspended biomass. Assuming the overall anaerobic digestion process conforms to first-order kinetics, the specific rate constant, K0, was determined for each of the experimental reactors. The average values obtained were: 0.080 h-1 (bentonite); 0.103 h-1 (zeolite); 0.180 h-1 (sepiolite); 0.198 h-1 (saponite); 0.131 h-1 (polyurethane); and 0.037 h-1 (control). The results indicate that the support used to immobilize the micro-organisms had a marked influence on the digestion process; the results were significant at the 95% confidence level. Methanogenic activity increased linearly with COD, with the saponite and sepiolite supports showing the highest values. The yield coefficient of methane was 270 ml of methane (under standard temperature and pressure conditions)/g of COD. The average elimination of COD was 89.5%. PMID:7917066

  4. Growth of silicone-immobilized bacteria on polycarbonate membrane filters, a technique to study microcolony formation under anaerobic conditions.

    PubMed Central

    Højberg, O; Binnerup, S J; Sørensen, J

    1997-01-01

    A technique was developed to study microcolony formation by silicone-immobilized bacteria on polycarbonate membrane filters under anaerobic conditions. A sudden shift to anaerobiosis was obtained by submerging the filters in medium which was depleted for oxygen by a pure culture of bacteria. The technique was used to demonstrate that preinduction of nitrate reductase under low-oxygen conditions was necessary for nonfermenting, nitrate-respiring bacteria, e.g., Pseudomonas spp., to cope with a sudden lack of oxygen. In contrast, nitrate-respiring, fermenting bacteria, e.g., Bacillus and Escherichia spp., formed microcolonies under anaerobic conditions with or without the presence of nitrate and irrespective of aerobic or anaerobic preculture conditions. PMID:9212439

  5. Comparative study of controlled pore glass, silica gel and poraver for the immobilization of urease to determine urea in a flow injection conductimetric biosensor system.

    PubMed

    Limbut, Warakorn; Thavarungkul, Panote; Kanatharana, Proespichaya; Asawatreratanakul, Punnee; Limsakul, Chusak; Wongkittisuksa, Booncharoen

    2004-03-15

    This study compared the responses of three enzyme reactors containing urease immobilized on three types of solid support, controlled pore glass (CPG), silica gel and Poraver. The evaluation of each enzyme reactor column was done in a flow injection conductimetric system. When urea in the sample solution passed though the enzyme reactor, urease catalysed the hydrolysis of urea into charged products. A lab-built conductivity meter was used to measure the increase in conductivity of the solution. The responses of the enzyme reactor column with urease immobilized on CPG and silica gel were similar and were much higher than that of Poraver. Both CPG and silica gel reactor columns gave the same limit of detection, 0.5 mM, and the response was still linear up to 150mM. The analysis time was 4-5 min per sample. The enzyme reactor column with urease immobilized on CPG gave a slightly better sensitivity, 4% higher than the reactor with silica gel. The life time of the immobilized urease on CPG and silica gel were more than 310h operation time (used intermittently over 7 months). Good agreement was obtained when urea concentrations of human serum samples determined by the flow injection conductimetric biosensor system was compared to the conventional methods (Fearon and Berthelot reactions). These were statistically shown using the regression line and Wilcoxon signed rank tests. The results showed that the reactor with urease immobilized on silica gel had the same efficiency as the reactor with urease immobilized on CPG. PMID:15128100

  6. Protein immobilization techniques for microfluidic assays

    PubMed Central

    Kim, Dohyun; Herr, Amy E.

    2013-01-01

    Microfluidic systems have shown unequivocal performance improvements over conventional bench-top assays across a range of performance metrics. For example, specific advances have been made in reagent consumption, throughput, integration of multiple assay steps, assay automation, and multiplexing capability. For heterogeneous systems, controlled immobilization of reactants is essential for reliable, sensitive detection of analytes. In most cases, protein immobilization densities are maximized, while native activity and conformation are maintained. Immobilization methods and chemistries vary significantly depending on immobilization surface, protein properties, and specific assay goals. In this review, we present trade-offs considerations for common immobilization surface materials. We overview immobilization methods and chemistries, and discuss studies exemplar of key approaches—here with a specific emphasis on immunoassays and enzymatic reactors. Recent “smart immobilization” methods including the use of light, electrochemical, thermal, and chemical stimuli to attach and detach proteins on demand with precise spatial control are highlighted. Spatially encoded protein immobilization using DNA hybridization for multiplexed assays and reversible protein immobilization surfaces for repeatable assay are introduced as immobilization methods. We also describe multifunctional surface coatings that can perform tasks that were, until recently, relegated to multiple functional coatings. We consider the microfluidics literature from 1997 to present and close with a perspective on future approaches to protein immobilization. PMID:24003344

  7. Immobilizing CC chemokine receptor 4's N-terminal extracellular tail on a capillary to study its potential ligands by capillary electrophoresis.

    PubMed

    Chen, Wenjing; Li, Meina; Yakufu, Pazilaiti; Ling, Xiaomei; Qi, Hui; Xiao, Junhai; Wang, Ying

    2012-04-01

    ML40 is the equivalent peptide derived from the N terminal of CCC4 (CC chemokine receptor 4), which plays a pivotal role in allergic inflammation. A new capillary electrophoresis method was developed to study the interactions between ML40 and its potential ligands in which ML40 was immobilized on the inner wall of capillary as the stationary phase based on the covalent linking technique. The interaction between S009, a known CCR4 antagonist, and the immobilized ML40 was studied to validate the bioactivity of ML40. The electropherogram of S009 showed that the peak height was reduced and the peak width was broadened in the ML40 immobilized capillary. Otherwise, 25 computer-aided design and drafting compounds were screened out using this method. Four compounds' peak widths were broadened and their peak heights were reduced, as with S009. Meanwhile, nonlinear chromatography was used to calculate the constants for the ligand-receptor complex formation. Furthermore, the tertiary amine compounds belonging to the chiral tertiary amines of the type NRR'R″, which are optically inactive resulting from rapid pyramide inversion, were chiral separated by our protein immobilization method for the first time. In general, the methodology presented would be applicable to study compound-ML40 interactions as a reliable and robust screening method for CCR4 antagonist discovery. PMID:22245764

  8. A comparative study on decolorization of reactive azo and indigoid dyes by free/immobilized pellets of Trametes versicolor and Funalia trogii.

    PubMed

    Yildirim, Seval Cing; Yesilada, Ozfer

    2015-11-01

    The objective of the present study was to investigate decolorization of Acid Blue 74 and Reactive Blue 198 dyes by free and immobilized white rot fungal pellets in order to confirm the possibility of practical application via repeated-batch cultivation. Decolorization studies were conducted using free pellets (FP), fungal cells immobilized on activated carbon (IFCAC) and pinewood (IFCP), and also fungal cells entrapped in alginate beads (FCEAB). No additional nitrogen and carbon source was used and high decolorization rates were achieved in only dye-contained media without pH adjustment. Acid Blue 74 was decolorized 96 and 94% within 2 hr by Trametes versicolor and Funalia trogii free pellets, respectively. These values were 87 and 84% for Reactive Blue 198, in this respect. Immobilization of fungal cells on pinewood increased the usability of pellets and the average decolorization efficiency of both dyes. The micro environment changed in the presence of pinewood and increased the stability of immobilized pellets. Decolorization was performed rapidly and efficiently. Laccase activity enhanced with availability of pinewood, and high laccase production with F. trogii was obtained. After separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), the molecular weight of T versicolor and F. trogii laccase bands was determined 64 and 61 kDa approximately. Green bands were obtained by the activity staining process with laccase substrate (ABTS) after gel renaturation step. PMID:26688979

  9. Effect of computerized cognitive training with virtual spatial navigation task during bed rest immobilization and recovery on vascular function: A pilot study

    PubMed Central

    Goswami, Nandu; Kavcic, Voyko; Marusic, Uros; Simunic, Bostjan; Rössler, Andreas; Hinghofer-Szalkay, Helmut; Pisot, Rado

    2015-01-01

    We investigated the effects of bed rest (BR) immobilization, with and without computerized cognitive training with virtual spatial navigation task (CCT), on vascular endothelium on older subjects. The effects of 14-day BR immobilization in healthy older males (n=16) of ages 53–65 years on endothelial function were studied using EndoPAT®, a noninvasive and user-independent method. From the group of 16 older men, 8 randomly received CCT during the BR, using virtual navigation tasks in a virtual environment with joystick device. In all the cases, EndoPAT assessments were done at pre- and post-BR immobilization as well as following 28 days of ambulatory recovery. The EndoPAT index increased from 1.53±0.09 (mean ± standard error of the mean) at baseline to 1.61±0.16 following immobilization (P=0.62) in the group with CCT. The EndoPAT index decreased from 2.06±0.13 (mean ± standard error of the mean) at baseline to 1.70±0.09 at the last day of BR study, day 14 (BR14) (P=0.09) in the control group. Additionally, there were no statistically significant differences between BR14 and at 28 days of follow-up (rehabilitation program) (R28). Our results show a trend of immobilization in older persons affecting the vasoconstrictory endothelial response. As the control subjects had a greater increase in EndoPAT index after R28 (+0.018) compared to subjects who had cognitive training (+0.11) (calculated from the first day of BR study), it is possible that cognitive training during BR does not improve endothelial function but rather contributes to slowing down the impairment of endothelial function. Finally, our results also show that EndoPAT may be a useful noninvasive tool to assess the vascular reactivity. PMID:25709419

  10. Production of L-glutamic Acid with Corynebacterium glutamicum (NCIM 2168) and Pseudomonas reptilivora (NCIM 2598): A Study on Immobilization and Reusability

    PubMed Central

    Shyamkumar, Rajaram; Moorthy, Innasi Muthu Ganesh; Ponmurugan, Karuppiah; Baskar, Rajoo

    2014-01-01

    Background L-glutamic acid is one of the major amino acids that is present in a wide variety of foods. It is mainly used as a food additive and flavor enhancer in the form of sodium salt. Corynebacterium glutamicum (C. glutamicum) is one of the major organisms widely used for glutamic acid production. Methods The study was dealing with immobilization of C. glutamicum and mixed culture of C. glutamicum and Pseudomonas reptilivora (P. reptilivora) for L-glutamic acid production using submerged fermentation. 2, 3 and 5% sodium alginate concentrations were used for production and reusability of immobilized cells for 5 more trials. Results The results revealed that 2% sodium alginate concentration produced the highest yield (13.026±0.247 g/l by C. glutamicum and 16.026±0.475 g/l by mixed immobilized culture). Moreover, reusability of immobilized cells was evaluated in 2% concentration with 5 more trials. However, when the number of cycles increased, the production of L-glutamic acid decreased. Conclusion Production of glutamic acid using optimized medium minimizes the time needed for designing the medium composition. It also minimizes external contamination. Glutamic acid production gradually decreased due to multiple uses of beads and consequently it reduces the shelf life. PMID:25215180

  11. Pilot Study to Evaluate Hydrogen Injection for Stimulating Reduction and Immobilization of Uranium in Groundwater at an ISR Mining Site

    NASA Astrophysics Data System (ADS)

    Clapp, L. W.; Cabezas, J.; Gamboa, Y.; Fernandez, W.

    2011-12-01

    State and federal regulations require that groundwater at in-situ recovery (ISR) uranium mining operations be restored to pre-mining conditions. Reverse osmosis (RO) filtration of several pore volumes of the post-leached groundwater and reinjection of the clean permeate is the most common technology currently used for restoring groundwater at uranium ISR sites. However, this approach does not revert the formation back to its initial reducing conditions, which can potentially impede timely groundwater restoration. In-situ biostimulation of indigenous iron- and sulfate reducing bacteria by injection of organic electron donors (e.g., ethanol, acetate, and lactate) to promote soluble uranium reduction and immobilization has been the subject of previous studies. However, injection of organic substrates has been observed to cause aquifer clogging near the injection point. In addition, U(VI) solubility may be enhanced through complexation with carbonate generated by organic carbon oxidation. An alternative approach that may overcome these problems involves the use of hydrogen as a reductant to promote microbial reduction and immobilization of U(VI) in situ. To test this approach, approximately 100,000 scf of compressed hydrogen gas was injected into a leached unconsolidated sand zone over two months at an ISR mining site. During this time groundwater was recirculated between injection and extraction wells (separated by 130 ft) at a rate of about 40 gpm and bromide was coinjected as a conservative tracer. A well monitoring program has been executed since June 2009 to evaluate the performance of the hydrogen injection. Current results show that U(VI) has been reduced from 4.2 to 0.05 ppm in the area surrounding the injection well and to 2.0 ± 0.3 ppm in the area surrounding the extraction well and two intermediate monitoring wells. Other water quality changes near the injection well include significant decreases in concentrations of Mo, sulfate, Fe, Mn, bicarbonate, Ca

  12. Exfoliated Egyptian kaolin immobilized heteropolyoxotungstate nanocomposite as an innovative antischistosomal agent: In vivo and in vitro bioactive studies.

    PubMed

    Bayaumy, Fatma E A; Darwish, Atef S

    2016-02-01

    This study aims to manipulate an antischistosomal nanocomposite based on exfoliated clay immobilized heteropolyoxotungstate. The nanocomposite's physicochemical characteristics were examined using XRD, Raman spectroscopy, FTIR, DLS, SEM, HR-TEM and AFM. Nano-sized spheroidal negatively charged Keggin-type heteropolyoxotungstate particles were developed along and between the exfoliated clay layers. The impact of the nanocomposite on Schistosoma mansoni-infected mice was studied through parasitological, physiological and histological analyses. Infected mice were orally vaccinated by a single nanocomposite dose (15mg/kg/day) for two weeks. The schistosomicidal activities of the nanocomposite in vitro were investigated by examining its dose- and time-dependent responses in terms of % worm mortality. The time-dependent morphological alterations in schistosomes at a nanocomposite dosage of 15μg/mL were followed by SEM. The nanocomposite exhibited potential schistosomicidal properties with a marked reduction in worm burden (~85% mortality), extensive deformities in the adult worm tegument and suckers, improvement of serum biochemical activities, and diminishment in granulomatous lesions. The in vitro release of heteropolyoxotungstate from exfoliated clay indicates the clay's ability to embrace the heteropolytungstate until its liberation at the parasitic districts. PMID:26652426

  13. Immobilization of quaternary ammonium salts on grafting particle polystyrene/SiO 2 and preliminary study of application performance

    NASA Astrophysics Data System (ADS)

    Gao, Baojiao; Qi, Changsheng; Liu, Qing

    2008-04-01

    Polystyrene (PSt) was grafted on the surface of silica gel particles in the manner of "grafting from" in a solution polymerization system, and grafting particles PSt/SiO 2 was obtained. The chloromethylation reaction of the grafted polystyrene was performed using a novel chloromethylation reagent, 1,4-bis(chloromethyoxy)butane which is un-carcinogenic, and grafting particles CMPS/SiO 2 was gained. Subsequently, grafted CMPS was quaternized (denoted as QPS) using tertiary amine, and finally functional composite-type particles QPS/SiO 2, on which quaternary ammonium groups were immobilized, were prepared. The catalysis activity of the particle QPS/SiO 2 as a triphase catalyst in phase-transfer catalysis systems and its antibacterial activity as a water-insoluble antibacterial material were studied preliminarily. The experimental results show that the particle QPS/SiO 2 exhibits higher catalysis activity as a triphase catalyst for the reaction between benzyl chloride in organic phase and sodium acetate in aqueous phase to form benzyl acetate, and under a mild condition of 60 °C for 7 h of reaction time a conversion of 66% for benzyl chloride can be obtained. The particle QPS/SiO 2 has high antibacterial activity as a water-insoluble antibacterial material against Escherichia coli ( E. coli).

  14. Microstructural and potential dependence studies of urease-immobilized gold nanoparticles-polypyrrole composite film for urea detection.

    PubMed

    Rajesh; Puri, Nidhi; Mishra, Sujeet K; Laskar, Mariam J; Srivastava, Avanish K

    2014-01-01

    Gold nanoparticle-polypyrrole nanocomposite film was electrochemically deposited in a single-step polymerization of pyrrole in the presence of 3-mercaptopropionic acid (MPA)-capped gold nanoparticles (GNPs) and p-toluenesulfonic acid (pTSA) on the surface of an indium tin oxide (ITO)-coated glass plate. The carboxyl functional groups surrounding the GNPs within the polymer matrix were utilized for the immobilization of urease enzyme through carbodiimide coupling reaction for the construction of a Urs/GNP(MPA)-PPy/ITO-glass bioelectrode for urea detection in Tris-HCl buffer. The resulting bioelectrode film was characterized by atomic force microscopy (AFM), high-resolution transmission electron microscopy (HRTEM), contact angle measurement, Fourier transform infrared spectroscopy (FTIR), and electrochemical techniques. The potentiometric response of the bioelectrode made of polymer nanocomposite films of two different thicknesses prepared at 100 and 250 mC cm(-2) charge densities, respectively, was studied towards the urea concentration in Tris-HCl buffer (pH 7.4). The thin polymer nanocomposite film-based bioelectrode prepared at 100 mC cm(-2) charge density exhibited a comparatively good potentiometric response than a thick 250 mC cm(-2) charge density film with a linear range of urea detection from 0.01 to 10 mM with a sensitivity of 29.7 mV per decade. PMID:24142354

  15. Skeletal fluorosis in immobilized extremities.

    PubMed

    Rosenquist, J B

    1975-11-01

    The effect of immobilization on skeletal fluorosis was studied in growing rabbits. One hind leg was immobilized by an external fixation device extending below the wrist joint and above the knee joint, the extremity being in a straight position after severance of the sciatic nerve. The animals, aged 7 weeks at the beginning of the experiment, were given 10 mg of fluoride per kg body weight and day during 12 weeks. In the tibiae, development of the skeletal fluorosis was more irregular than that observed in previous studies of normally active animals, being most excessive in the mobile bone. The immobilization effect was most profound in the femora as the cortical thickness and the femur score were significantly higher than those in the mobile femora. It was suggested that an altered muscular activity was the reason for the observed changes. PMID:1189918

  16. Solid-state NMR studies of proteins immobilized on inorganic surfaces

    SciTech Connect

    Shaw, Wendy J.

    2015-09-01

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin and leucine rich amelogenin protein (LRAP), have been studied in depth and have different features, challenging our ability to extract design principles. More recent studies of the significantly larger full-length amelogenin represent a challenging but necessary step to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids and silaffin peptide with silica are also being studied, along with qualitative studies of proteins interacting with calcium carbonate. Dipolar recoupling techniques have formed the core of the quantitative studies, yet, the need for isolated spin pairs makes this approach costly and time intensive. The use of multi-dimensional techniques is advancing, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area..

  17. Solid-state NMR studies of proteins immobilized on inorganic surfaces

    DOE PAGESBeta

    Shaw, Wendy J.

    2014-10-29

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin and leucine rich amelogenin protein (LRAP), have been studied in depth and have different features, challenging our ability to extract design principles. More recent studies of the significantly larger full-length amelogenin represent a challenging but necessary step to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids and silaffin peptide with silica are also being studied, along with qualitative studies of proteins interacting with calcium carbonate. Dipolar recoupling techniquesmore » have formed the core of the quantitative studies, yet, the need for isolated spin pairs makes this approach costly and time intensive. The use of multi-dimensional techniques is advancing, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area.« less

  18. Solid-state NMR studies of proteins immobilized on inorganic surfaces

    SciTech Connect

    Shaw, Wendy J.

    2014-10-29

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin and leucine rich amelogenin protein (LRAP), have been studied in depth and have different features, challenging our ability to extract design principles. More recent studies of the significantly larger full-length amelogenin represent a challenging but necessary step to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids and silaffin peptide with silica are also being studied, along with qualitative studies of proteins interacting with calcium carbonate. Dipolar recoupling techniques have formed the core of the quantitative studies, yet, the need for isolated spin pairs makes this approach costly and time intensive. The use of multi-dimensional techniques is advancing, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area.

  19. Solid-state NMR studies of proteins immobilized on inorganic surfaces

    PubMed Central

    Shaw, Wendy J.

    2015-01-01

    Solid state NMR is the primary tool for studying the quantitative, site-specific structure, orientation, and dynamics of biomineralization proteins under biologically relevant conditions. Two calcium phosphate proteins, statherin (43 amino acids) and leucine rich amelogenin protein (LRAP; 59 amino acids), have been studied in depth and have different dynamic properties and 2D- and 3D-structural features. These differences make it difficult to extract design principles used in nature for building materials with properties such as high strength, unusual morphologies, or uncommon phases. Consequently, design principles needed for developing synthetic materials controlled by proteins are not clear. Many biomineralization proteins are much larger than statherin and LRAP, necessitating the study of larger biomineralization proteins. More recent studies of the significantly larger full-length amelogenin (180 residues) represent a significant step forward to ultimately investigate the full diversity of biomineralization proteins. Interactions of amino acids, a silaffin derived peptide, and the model LK peptide with silica are also being studied, along with qualitative studies of the organic matrices interacting with calcium carbonate. Dipolar recoupling techniques have formed the core of the quantitative studies, yet the need for isolated spin pairs makes this approach costly and time intensive. The use of multidimensional techniques to study biomineralization proteins is becoming more common, methodology which, despite its challenges with these difficult-to-study proteins, will continue to drive future advancements in this area. PMID:25466354

  20. Immobilization of bovine catalase onto magnetic nanoparticles.

    PubMed

    Doğaç, Yasemin İspirli; Teke, Mustafa

    2013-01-01

    The scope of this study is to achieve carrier-bound immobilization of catalase onto magnetic particles (Fe₃O₄ and Fe₂O₃NiO₂ · H₂O) to specify the optimum conditions of immobilization. Removal of H2O2 and the properties of immobilized sets were also investigated. To that end, adsorption and then cross-linking methods onto magnetic particles were performed. The optimum immobilization conditions were found for catalase: immobilization time (15 min for Fe₃O₄; 10 min for Fe2O₃NiO₂ · H₂O), the initial enzyme concentration (1 mg/mL), amount of magnetic particles (25 mg), and glutaraldehyde concentration (3%). The activity reaction conditions (optimum temperature, optimum pH, pH stability, thermal stability, operational stability, and reusability) were characterized. Also kinetic parameters were calculated by Lineweaver-Burk plots. The optimum pH values were found to be 7.0, 7.0, and 8.0 for free enzyme, Fe₃O₄-immobilized catalases, and Fe₂O₃NiO₂ · H₂O-immobilized catalases, respectively. All immobilized catalase systems displayed the optimum temperature between 25 and 35°C. Reusability studies showed that Fe₃O₄-immobilized catalase can be used 11 times with 50% loss in original activity, while Fe2O₃NiO₂ · H₂O-immobilized catalase lost 67% of activity after the same number of uses. Furthermore, immobilized catalase systems exhibited improved thermal and pH stability. The results transparently indicate that it is possible to have binding between enzyme and magnetic nanoparticles. PMID:23876136

  1. Ultra-small rhenium nanoparticles immobilized on DNA scaffolds: An excellent material for surface enhanced Raman scattering and catalysis studies.

    PubMed

    Anantharaj, S; Sakthikumar, K; Elangovan, Ayyapan; Ravi, G; Karthik, T; Kundu, Subrata

    2016-12-01

    Highly Sensitive and ultra-small Rhenium (Re) metal nanoparticles (NPs) were successfully stabilized in water by the staging and fencing action of the versatile biomolecule DNA that resulted in two distinct aggregated chain-like morphologies with average grain sizes of 1.1±0.1nm and 0.7±0.1nm for the very first time within a minute of reaction time. Re NPs are formed by the borohydride reduction of ammonium perrhenate (NH4ReO4) in the presence of DNA at room temperature (RT) under stirring. The morphologies were controlled by carefully monitoring the molar ratio of NH4ReO4 and DNA. The synthesized material was employed in two potential applications: as a substrate for surface enhanced Raman scattering (SERS) studies and as a catalyst for the reduction of aromatic nitro compounds. SERS study was carried out by taking methylene blue (MB) as the probe and the highest SERS enhancement factor (EF) of 2.07×10(7) was found for the aggregated chain-like having average grain size of 0.7±0.1nm. Catalytic reduction of 4-nitro phenol (4-NP), 2-nitro phenol (2-NP) and 4-nitroaniline (4-NA) with a rate constant value of 6×10(-2)min(-1), 33.83×10(-2)min(-1) and 37.4×10(-2)min(-1) have testified the excellent catalytic performance of our Re NPs immobilized on DNA. The overall study have revealed the capability of DNA in stabilizing the highly reactive Re metal at nanoscale and made them applicable in practice. The present route can also be extended to prepare one dimensional (1-D), self-assembled NPs of other reactive metals, mixed metals or even metal oxides for specific applications in water based solutions. PMID:27571687

  2. Penetrable silica microspheres for immobilization of bovine serum albumin and their application to the study of the interaction between imatinib mesylate and protein by frontal affinity chromatography.

    PubMed

    Ma, Liyun; Li, Jing; Zhao, Juan; Liao, Han; Xu, Li; Shi, Zhi-guo

    2016-01-01

    In the current study, novel featured silica, named penetrable silica, simultaneously containing macropores and mesopores, was immobilized with bovine serum albumin (BSA) via Schiff base method. The obtained BSA-SiO2 was employed as the high-performance liquid chromatographic (HPLC) stationary phase. Firstly, D- and L-tryptophan were used as probes to investigate the chiral separation ability of the BSA-SiO2 stationary phase. An excellent enantioseparation factor was obtained up to 4.3 with acceptable stability within at least 1 month. Next, the BSA-SiO2 stationary phase was applied to study the interaction between imatinib mesylate (IM) and BSA by frontal affinity chromatography. A single type of binding site was found for IM with the immobilized BSA, and the hydrogen-bonding and van der Waals interactions were expected to be contributing interactions based on the thermodynamic studies, and this was a spontaneous process. Compared to the traditional silica for HPLC stationary phase, the proposed penetrable silica microsphere possessed a larger capacity to bond more BSA, minimizing column overloading effects and enhancing enantioseparation ability. In addition, the lower running column back pressure and fast mass transfer were meaningful for the column stability and lifetime. It was a good substrate to immobilize biomolecules for fast chiral resolution and screening drug-protein interactions. PMID:26573171

  3. A comparative study of the most effective amendment for Pb, Zn and Cd immobilization in contaminated soils.

    PubMed

    Szrek, Dominik; Bajda, Tomasz; Manecki, Maciej

    2011-01-01

    The problem of an extensive contamination of soils with metals can be resolved using an in situ chemical immobilization technology. Five substances (natural zeolite, bog iron ore, "Polifoska 15" fertilizer, triple superphosphate, diammonium phosphate) were tested to determine their efficiency to immobilize Zn, Pb and Cd in smelter-contaminated soil in the Upper Silesia region. Soil samples were collected at three sites located in the vincity of a Pb-Zn smelter and a sludge landfill near the town of Bukowno. Effective reduction of leachable and fitoavailable Zn, Pb and Cd concentrations in soil was observed after addition of diammonium phosphate, "Polifoska 15" fertilizer and bog iron ore amendments. Additional test proved that immobilization effect gained by these amendments sustains at low-temperature conditions. It was noticed that phosphate addition resulted in lowering pH and mobilization of As(V) in soils. Good immobilization effectiveness and lack of major adverse effects of bog iron application suggest that this is the method of choice. PMID:21961559

  4. Zinc Oxide Nanoparticles Supported Lipase Immobilization for Biotransformation in Organic Solvents: A Facile Synthesis of Geranyl Acetate, Effect of Operative Variables and Kinetic Study.

    PubMed

    Patel, Vrutika; Shah, Chandani; Deshpande, Milind; Madamwar, Datta

    2016-04-01

    The present study describes grafting of zinc oxide (ZnO) nanoparticles with polyethyleneimine (PEI) followed by modification with glutraldehyde used as the bridge for binding the enzyme to support. The prepared nanocomposites were then characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy, utilized for synthesis of geranyl acetate in n-hexane. Among all the three prepared nanocomposites (ZnO + PEI, ZnO + PEI + SAA, ZnO + PEI + GLU), Candida rugosa lipase immobilized on ZnO-PEI-GLU was found to be best for higher ester synthesis. The operating conditions that maximized geranyl acetate resulted in the highest yield of 94 % in 6 h, molar ratio of 0.1:0.4 M (geraniol/vinyl acetate) in the presence of n-hexane as reaction medium. Various kinetic parameters such as V max, K i(G), K m(G), and K m(VA) were determined using nonlinear regression analysis for order bi-bi mechanism. The kinetic study showed that reaction followed order bi-bi mechanism with inhibition by geraniol. Activation energy (E a ) was found to be lower for immobilized lipase (12.31 kJ mol(-1)) than crude lipase (19.04 kJ mol(-1)) indicating better catalytic efficiency of immobilized lipase. Immobilized biocatalyst demonstrated 2.23-fold increased catalytic activity than crude lipase and recycled 20 times. The studies revealed in this work showed a promising perspective of using low-cost nanobiocatalysts to overcome the well-known drawbacks of the chemical-catalyzed route. PMID:26749293

  5. Activation and deactivation of a robust immobilized Cp*Ir-transfer hydrogenation catalyst: a multielement in situ X-ray absorption spectroscopy study.

    PubMed

    Sherborne, Grant J; Chapman, Michael R; Blacker, A John; Bourne, Richard A; Chamberlain, Thomas W; Crossley, Benjamin D; Lucas, Stephanie J; McGowan, Patrick C; Newton, Mark A; Screen, Thomas E O; Thompson, Paul; Willans, Charlotte E; Nguyen, Bao N

    2015-04-01

    A highly robust immobilized [Cp*IrCl2]2 precatalyst on Wang resin for transfer hydrogenation, which can be recycled up to 30 times, was studied using a novel combination of X-ray absorption spectroscopy (XAS) at Ir L3-edge, Cl K-edge, and K K-edge. These culminate in in situ XAS experiments that link structural changes of the Ir complex with its catalytic activity and its deactivation. Mercury poisoning and "hot filtration" experiments ruled out leached Ir as the active catalyst. Spectroscopic evidence indicates the exchange of one chloride ligand with an alkoxide to generate the active precatalyst. The exchange of the second chloride ligand, however, leads to a potassium alkoxide-iridate species as the deactivated form of this immobilized catalyst. These findings could be widely applicable to the many homogeneous transfer hydrogenation catalysts with Cp*IrCl substructure. PMID:25768298

  6. Inhibition of fibroblast adhesion by covalently immobilized protein repellent polymer coatings studied by single cell force spectroscopy.

    PubMed

    Aliuos, Pooyan; Sen, Aromita; Reich, Uta; Dempwolf, Wibke; Warnecke, Athanasia; Hadler, Christoph; Lenarz, Thomas; Menzel, Henning; Reuter, Guenter

    2014-01-01

    Cochlea implants (CI) restore the hearing in patients with sensorineural hearing loss by electrical stimulation of the auditory nerve via an electrode array. The increase of the impedance at the electrode-tissue interface due to a postoperative connective tissue encapsulation leads to higher power consumption of the implants. Therefore, reduced adhesion and proliferation of connective tissue cells around the CI electrode array is of great clinical interest. The adhesion of cells to substrate surfaces is mediated by extracellular matrix (ECM) proteins. Protein repellent polymers (PRP) are able to inhibit unspecific protein adsorption. Thus, a reduction of cell adhesion might be achieved by coating the electrode carriers with PRPs. The aim of this study was to investigate the effects of two different PRPs, poly(dimethylacrylamide) (PDMAA) and poly(2-ethyloxazoline) (PEtOx), on the strength and the temporal dynamics of the initial adhesion of fibroblasts. Polymers were immobilized onto glass plates by a photochemical grafting onto method. Water contact angle measurements proved hydrophilic surface properties of both PDMAA and PEtOx (45 ± 1° and 44 ± 1°, respectively). The adhesion strength of NIH3T3 fibroblasts after 5, 30, and 180 s of interaction with surfaces was investigated by using single cell force spectroscopy. In comparison to glass surfaces, both polymers reduced the adhesion of fibroblasts significantly at all different interaction times and lower dynamic rates of adhesion were observed. Thus, both PDMAA and PEtOx represented antiadhesive properties and can be used as implant coatings to reduce the unspecific ECM-mediated adhesion of fibroblasts to surfaces. PMID:23596088

  7. A nanoparticle-based immobilization assay for prion-kinetics study

    PubMed Central

    Kouassi, Gilles K; Irudayaraj, Joseph

    2006-01-01

    Magnetic and gold coated magnetic nanoparticles were synthesized by co-precipitation of ferrous and ferric chlorides, and by the micromicelles method, respectively. Synthesized nanoparticles were functionalized to bear carboxyl and amino acid moieties and used as prion protein carriers after carbodiimide activation in the presence of N-hydroxysuccinimide. The binding of human recombinant prion protein (huPrPrec) to the surface of these nanoparticles was confirmed by FTIR and the size and structures of the particles were characterized by transmission electron microscopy. Findings indicate that the rate of prion binding increased only slightly when the concentration of prion in the reaction medium was increased. Rate constants of binding were very similar on Fe3O4@Au and Fe3O4-LAA when the concentrations of protein were 1, 2, 1.5, 2.25 and 3.57 μg/ml. For a 5 μg/ml concentration of huPrPrec the binding rate constant was higher for the Fe3O4-LAA particles. This study paves the way towards the formation of prion protein complexes onto a 3-dimensional structure that could reveal obscure physiological and pathological structure and prion protein kinetics. PMID:16916458

  8. Continuous Production of Alkyl Esters Using an Immobilized Lipase Bioreactor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An immobilized lipase packed-bed bioreactor was developed for esterifying the free fatty acids in greases as a pretreatment step in the production of their simple alkyl esters for use as biodiesel. The immobilized lipases used in the study were immobilized preparations of Candida antarctica (C. a.)...

  9. Plutonium immobilization -- Can loading

    SciTech Connect

    Kriikku, E.

    2000-02-17

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Project (PIP). The PIP adds the excess plutonium to ceramic pucks, loads the pucks into cans, and places the cans into DWPF canisters. This paper discusses the PIP process steps, the can loading conceptual design, can loading equipment design, and can loading work completed.

  10. The Experimental Study of the Performance of Nano-Thin Polyelectrolyte Shell for Dental Pulp Stem Cells Immobilization.

    PubMed

    Grzeczkowicz, A; Granicka, L H; Maciejewska, I; Strawski, M; Szklarczyk, M; Borkowska, M

    2015-12-01

    Carious is the most frequent disease of mineralized dental tissues which might result in dental pulp inflammation and mortality. In such cases an endodontic treatment is the only option to prolong tooth functioning in the oral cavity; however, in the cases of severe pulpitis, especially when complicated with periodontal tissue inflammation, the endodontic treatment might not be enough to protect against tooth loss. Thus, keeping the dental pulp viable and/or possibility of the reconstruction of a viable dental pulp complex, appears to become a critical factor for carious and/or pulp inflammation treatment. The nowadays technologies, which allow handling dental pulp stem cells (DPSC), seem to bring us closer to the usage of dental stem cells for tooth tissues reconstruction. Thus, DPSC immobilized within nano-thin polymeric shells, allowing for a diffusion of produced factors and separation from bacteria, may be considered as a cover system supporting technology of dental pulp reconstruction. The DPSC were immobilized using a layer-by-layer technique within nano-thin polymeric shells constructed and modified by nanostructure involvement to ensure the layers stability and integrity as well as separation from bacterial cells. The cytotoxity of the material used for membrane production was assessed on the model of adherent cells. The performance of DPSC nano-coating was assessed in vitro. Membrane coatings showed no cytotoxicity on the immobilized cells. The presence of coating shell was confirmed with flow cytometry, atomic force microscopy and visualized with fluorescent microscopy. The transfer of immobilized DPSC within the membrane system ensuring cells integrity, viability and protection from bacteria should be considered as an alternative method for dental tissues transportation and regeneration. PMID:26682375

  11. Study of whey fermentation by kefir immobilized on low cost supports using 14C-labelled lactose.

    PubMed

    Soupioni, Magdalini; Golfinopoulos, Aristidis; Kanellaki, Maria; Koutinas, Athanasios A

    2013-10-01

    Brewer's Spent Grains (BSG) and Malt Spent Rootlets (MSR) were used as supports for kefir cells immobilization and the role of lactose uptake rate by kefir in the positive activity of produced biocatalysts during whey fermentation was investigated. Lactose uptake rate by the immobilized cells was recorded using (14)C-labelled lactose and the effect of various conditions (pH, temperature and kind of support) on it and consequently on fermentation time and ethanol production was examined. The results showed that lactose uptake rate was correlated to fermentation rate and increased as temperature was increased up to 30°C at pH 5.5. The same results have been recently noticed by using biocatalysts with Delignified Cellulosic Materials (DCM) and Gluten Pellets (GP), but fermentation time of about 7h by kefir immobilized on DCM and BSG resulted to two fold lower than that on GP and MSR. The highest alcohol concentration was observed by MSR. PMID:23385156

  12. Immobilization and characterization of a thermostable lipase.

    PubMed

    Song, Chongfu; Sheng, Liangquan; Zhang, Xiaobo

    2013-12-01

    Lipases have found a number of commercial applications. However, thermostable lipase immobilized on nanoparticle is not extensively characterized. In this study, a recombinant thermostable lipase (designated as TtL) from Thermus thermophilus WL was expressed in Escherichia coli and immobilized onto 3-APTES-modified Fe3O4@SiO2 supermagnetic nanoparticles. Based on analyses with tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer observation, the diameter of immobilized lipase nanoparticle was 18.4 (± 2.4) nm, and its saturation magnetization value was 52.3 emu/g. The immobilized lipase could be separated from the reaction medium rapidly and easily in a magnetic field. The biochemical characterizations revealed that, comparing with the free one, the immobilized lipase exhibited better resistance to temperature, pH, metal ions, enzyme inhibitors, and detergents. The K m value for the immobilized TtL (2.56 mg/mL) was found to be lower than that of the free one (3.74 mg/mL), showing that the immobilization improved the affinity of lipase for its substrate. In addition, the immobilized TtL exhibited good reusability. It retained more than 79.5 % of its initial activity after reusing for 10 cycles. Therefore, our study presented that the possibility of the efficient reuse of the thermostable lipase immobilized on supermagnetic nanoparticles made it attractive from the viewpoint of practical application. PMID:23748908

  13. Effectiveness of olive oil for the prevention of pressure ulcers caused in immobilized patients within the scope of primary health care: study protocol for a randomized controlled trial

    PubMed Central

    2013-01-01

    Background Pressure ulcers are considered an important issue, mainly affecting immobilized older patients. These pressure ulcers increase the care burden for the professional health service staff as well as pharmaceutical expenditure. There are a number of studies on the effectiveness of different products used for the prevention of pressure ulcers; however, most of these studies were carried out at a hospital level, basically using hyperoxygenated fatty acids (HOFA). There are no studies focused specifically on the use of olive-oil-based products and therefore this research is intended to find the most cost-effective treatment and achieve an alternative treatment. Methods/design The main objective is to assess the effectiveness of olive oil, comparing it with HOFA, to treat immobilized patients at home who are at risk of pressure ulcers. As a secondary objective, the cost-effectiveness balance of this new application with regard to the HOFA will be assessed. The study is designed as a noninferiority, triple-blinded, parallel, multi-center, randomized clinical trial. The scope of the study is the population attending primary health centers in Andalucía (Spain) in the regional areas of Malaga, Granada, Seville, and Cadiz. Immobilized patients at risk of pressure ulcers will be targeted. The target group will be treated by application of an olive-oil-based formula whereas the control group will be treated by application of HOFA to the control group. The follow-up period will be 16 weeks. The main variable will be the presence of pressure ulcers in the patient. Secondary variables include sociodemographic and clinical information, caregiver information, and whether technical support exists. Statistical analysis will include the Kolmogorov-Smirnov test, symmetry and kurtosis analysis, bivariate analysis using the Student’s t and chi-squared tests as well as the Wilcoxon and the Man-Whitney U tests, ANOVA and multivariate logistic regression analysis. Discussion The

  14. Diffusion of solutes inside bacterial colonies immobilized in model cheese depends on their physicochemical properties: a time-lapse microscopy study

    PubMed Central

    Floury, Juliane; El Mourdi, Ilham; Silva, Juliana V. C.; Lortal, Sylvie; Thierry, Anne; Jeanson, Sophie

    2015-01-01

    During cheese processing and ripening, bacteria develop as colonies. Substrates and metabolites must then diffuse either from or into the colonies. Exploring how the inner cells of the colony access the substrates or get rid of the products leads to study the diffusion of solutes inside bacterial colonies immobilized in cheese. Diffusion limitations of substrates within the bacterial colony could lead to starvation for the cells in the center of the colony. This study aimed at better understands ripening at the colony level, by investigating how diffusion phenomena inside colonies vary depending on both the physicochemical properties of the solutes and Lactococcus lactis strain. Dextrans (4, 70, and 155 kDa) and milk proteins (BSA, lactoferrin and αS1-casein) of different sizes and physicochemical properties were chosen as model of diffusing solutes, and two L. lactis strains presenting different surface properties were immobilized as colonies in a model cheese. Diffusion of solutes inside and around colonies was experimentally followed by time-lapse confocal microscopy. Dextran solutes diffused inside both lactococci colonies with a non-significantly different effective diffusion coefficient, which depended mainly on size of the solute. However, whereas flexible and neutral hydrophilic polymers such as dextran can diffuse inside colonies whatever its size, none of the three proteins investigated in this study could penetrate inside lactococci colonies. Therefore, the diffusion behavior of macromolecules through bacterial colonies immobilized in a model cheese did not only depends on the size of the diffusing solutes, but also and mainly on their physicochemical properties. Milk caseins are probably first hydrolyzed by the cell wall proteases of L. lactis and/or other proteases present in the cheese, and then the generated peptides diffuse inside colonies to be further metabolized into smaller peptides and amino acids by all the cells located inside the colonies

  15. Hyperalgesia in an immobilized rat hindlimb: effect of treadmill exercise using non-immobilized limbs.

    PubMed

    Chuganji, Sayaka; Nakano, Jiro; Sekino, Yuki; Hamaue, Yohei; Sakamoto, Junya; Okita, Minoru

    2015-01-01

    Cast immobilization of limbs causes hyperalgesia, which is a decline of the threshold of mechanical and thermal mechanical stimuli. The immobilization-induced hyperalgesia (IIH) can disturb rehabilitation and activities of daily living in patients with orthopedic disorders. However, it is unclear what therapeutic and preventive approaches can be used to alleviate IIH. Exercise that activates the descending pain modulatory system may be effective for IIH. The purpose of this study was to investigate the effects of treadmill exercise during the immobilization period, using the non-immobilized limbs, on IIH. Thirty-six 8-week-old Wistar rats were randomly divided into (1) control, (2) immobilization (Im), and (3) immobilization and treadmill exercise (Im+Ex) groups. In the Im and Im+Ex groups, the right ankle joints of each rat were immobilized in full plantar flexion with a plaster cast for an 8-week period. In the Im+Ex group, treadmill exercise (15 m/min, 30 min/day, 5 days/week) was administered during the immobilization period while the right hindlimb was kept immobilized. Mechanical hyperalgesia was measured using von Frey filaments every week. To investigate possible activation of the descending pain modulatory system, beta-endorphin expression levels in hypothalamus and midbrain periaqueductal gray were analyzed. Although IIH clearly occurred in the Im group, the hyperalgesia was partially but significantly reduced in the Im+Ex group. Beta-endorphin, which is one of the endogenous opioids, was selectively increased in the hypothalamus and midbrain periaqueductal gray of the Im+Ex group. Our data suggest that treadmill running using the non-immobilized limbs reduces the amount of hyperalgesia induced in the immobilized limb even if it is not freed. This ameliorating effect might be due to the descending pain modulatory system being activated by upregulation of beta-endorphin in the brain. PMID:25304541

  16. Plutonium Immobilization Puck Handling

    SciTech Connect

    Kriikku, E.

    1999-01-26

    The Plutonium Immobilization Project (PIP) will immobilize excess plutonium and store the plutonium in a high level waste radiation field. To accomplish these goals, the PIP will process various forms of plutonium into plutonium oxide, mix the oxide powder with ceramic precursors, press the mixture into pucks, sinter the pucks into a ceramic puck, load the pucks into metal cans, seal the cans, load the cans into magazines, and load the magazines into a Defense Waste Processing Facility (DPWF) canister. These canisters will be sent to the DWPF, an existing Savannah River Site (SRS) facility, where molten high level waste glass will be poured into the canisters encapsulating the ceramic pucks. Due to the plutonium radiation, remote equipment will perform these operations in a contained environment. The Plutonium Immobilization Project is in the early design stages and the facility will begin operation in 2005. This paper will discuss the Plutonium Immobilization puck handling conceptual design and the puck handling equipment testing.

  17. Immobilization induced hypercalcemia

    PubMed Central

    Cano-Torres, Edgar Alonso; González-Cantú, Arnulfo; Hinojosa-Garza, Gabriela; Castilleja-Leal, Fernando

    2016-01-01

    Summary Immobilization hypercalcemia is an uncommon diagnosis associated with increased bone remodeling disorders and conditions associated with limited movement such as medullar lesions or vascular events. Diagnosis requires an extensive evaluation to rule out other causes of hypercalcemia. This is a report of a woman with prolonged immobilization who presented with severe hypercalcemia. This case contributes to identification of severe hypercalcemia as a result of immobility and the description of bone metabolism during this state. PMID:27252745

  18. Immobilization of horseradish peroxidase on modified chitosan beads.

    PubMed

    Monier, M; Ayad, D M; Wei, Y; Sarhan, A A

    2010-04-01

    A method has been developed to immobilize horseradish peroxidase (HRP) on modified chitosan beads by means of graft copolymerization of polyethylacrylate in presence of potassium persulphate and Mohr's salt redox initiator. The activity of free and immobilized HRP was studied. FTIR spectroscopy and scanning electron microscopy were used to characterize HRP immobilization. The efficiency of the immobilization was investigated by examining the relative enzymatic activity of free enzyme before and after the HRP immobilization. The obtained values were found to reach 98.4%. The results show that the optimum temperature of immobilized HRP was 45 degrees C, which was identical to that of free enzyme, and the immobilized HRP exhibited a higher relative activity than that of free HRP over 45 degrees C. The optimal pH for immobilized HRP was 10, which was higher than that of the free HRP (pH 9.0), and the immobilization resulted in stabilization of enzyme over a broader pH range. The apparent kinetic constant value (K(m)) of immobilized HRP was 3.784 mmol ml(-1), which was higher than that of free HRP. On the other hand, the activity of immobilized HRP decreased slowly against time when compared to that of the free HRP, and could retain 65.8% residual activity after 6 consecutive cycles. PMID:20060854

  19. Immobilized Cell and Enzyme Technology

    NASA Astrophysics Data System (ADS)

    Dunnill, P.

    1980-08-01

    The development of immobilized enzyme and cell technology is summarized. Industrial processes for sucrose inversion, penicillin deacylation and glucose isomerization using immobilized enzymes are described. An alternative process for glucose isomerization using immobilized cells, and some other industrial applications of immobilized cells are indicated. Recent developments in immobilized enzyme and cell technology are assessed and the relative merits of the different biochemical catalyst forms are considered.

  20. Study of the potential of the air lift bioreactor for xylitol production in fed-batch cultures by Debaryomyces hansenii immobilized in alginate beads.

    PubMed

    Pérez-Bibbins, Belinda; de Souza Oliveira, Ricardo Pinheiro; Torrado, Ana; Aguilar-Uscanga, María Guadalupe; Domínguez, José Manuel

    2014-01-01

    Cell immobilization has shown to be especially adequate for xylitol production. This work studies the suitability of the air lift bioreactor for xylitol production by Debaryomyces hansenii immobilized in Ca-alginate operating in fed-batch cultures to avoid substrate inhibition. The results showed that the air lift bioreactor is an adequate system since the minimum air flow required for fluidization was even lower than that leading to the microaerobic conditions that trigger xylitol accumulation by this yeast, also maintaining the integrity of the alginate beads and the viability of the immobilized cells until 3 months of reuses. Maximum productivities and yields of 0.43 g/l/h and 0.71 g/g were achieved with a xylose concentration of 60 g/l after each feeding. The xylose feeding rate, the air flow, and the biomass concentration at the beginning of the fed-batch operation have shown to be critical parameters for achieving high productivities and yields. Although a maximum xylitol production of 139 g/l was obtained, product inhibition was evidenced in batch experiments, which allowed estimating at 200 and 275 g/l the IC50 for xylitol productivity and yield, respectively. The remarkable production of glycerol in the absence of glucose was noticeable, which could not only be attributed to the osmoregulatory function of this polyol in conditions of high osmotic pressure caused by high xylitol concentrations but also to the role of the glycerol synthesis pathway in the regeneration of NAD(+) in conditions of suboptimal microaeration caused by insufficient aeration or high oxygen demand when high biomass concentrations were achieved. PMID:24136467

  1. Site-specific, reversible and fluorescent immobilization of proteins on CrAsH-modified surfaces for microarray analytics.

    PubMed

    Schulte-Zweckel, Janine; Rosi, Federica; Sreenu, Domalapally; Schröder, Hendrik; Niemeyer, Christof M; Triola, Gemma

    2014-10-28

    A novel technique for protein immobilization onto CrAsH-modified surfaces is presented. This approach enables an efficient, reversible and fluorogenic immobilization of proteins. Moreover, expressed proteins can also be directly immobilized from cellular lysates without prior purification. The immobilized proteins are suitable for protein-protein interaction studies and the fluorescence enhancement upon immobilization can be employed for the direct detection of the immobilized protein without the need for secondary detection methods. PMID:25207673

  2. Ultra-low field T1 vs. T1rho at 3T and 7T: study of rotationally immobilized protein gels and animal brain tissues

    NASA Astrophysics Data System (ADS)

    Dong, Hui; Inglis, Ben; Barr, Ian; Clarke, John

    2015-03-01

    Clinical magnetic resonance imaging (MRI) machines operating in static fields of typically 1.5 T or 3 T can capture information on slow molecular dynamics utilizing the so-called T1rho technique. This technique, in which a radiofrequency (RF) spin-lock field is applied with microtesla amplitude, has been used, for example, to determine the onset time of stroke in studies on rats. The long RF pulse, however, may exceed the specific absorption rate (SAR) limit, putting subjects at risk. Ultra-low-field (ULF) MRI, based on Superconducting Quantum Interference Devices (SQUIDs), directly detects proton signals at a static magnetic field of typically 50-250 μT. Using our ULF MRI system with adjustable static field of typically 55 to 240 μT, we systematically measured the T1 and T2 dispersion profiles of rotationally immobilized protein gels (bovine serum albumin), ex vivo pig brains, and ex vivo rat brains with induced stroke. Comparing the ULF results with T1rho dispersion obtained at 3 T and 7 T, we find that the degree of protein immobilization determines the frequency-dependence of both T1 and T1rho. Furthermore, T1rho and ULF T1 show similar results for stroke, suggesting that ULF MRI may be used to image traumatic brain injury with negligible SAR. This research was supported by the Henry H. Wheeler, Jr. Brain Imaging Center and the Donaldson Trust.

  3. A comparative study of different protein immobilization methods for the construction of an efficient nano-structured lactate oxidase-SWCNT-biosensor

    PubMed Central

    Pagán, Miraida; Suazo, Dámaris; del Toro, Nicole; Griebenow, Kai

    2014-01-01

    We constructed lactate biosensors by immobilization of lactate oxidase (LOx) onto a single-walled carbon nanotube (SWCNT) electrode. The first step of the sensor construction was the immobilization of oxidized SWCNT onto a platinum electrode modified with 4-aminothiophenol (4-ATP). Two enzyme immobilization methods were used to construct the biosensors, i.e., covalent immobilization using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and physical adsorption. Atomic force microscopy (AFM) experiments confirmed the immobilization of SWCNT during the biosensor construction and X-ray photoelectron spectroscopy (XPS) experiments confirmed covalent immobilization of LOx onto the SWCNT in the first method. The biosensor based on covalent enzyme immobilization showed a sensitivity of 5.8 μA/mM, a linearity up to 0.12 mM of L-lactate, and a detection limit of 4.0 μM. The biosensor based on protein adsorption displayed a sensitivity of 9.4 μA/mM, retaining linearity up to 0.18 mM of L-lactate with a detection limit of 3.0 μM. The difference in the biosensor response can be attributed to protein conformational or dynamical changes during covalent immobilization. The stability of the biosensors was tested at different temperatures and after different storage periods. The thermostability of the biosensors after incubation at 60°C demonstrated that the biosensor with covalently immobilized LOx retained a higher response compare with the adsorbed protein. Long-term stability experiments show a better residual activity of 40% for the covalently immobilized protein compared to 20% of residual activity for the adsorbed protein after 25 d storage. Covalent protein immobilization was superior compared to adsorption in preserving biosensor functionality over extended time period. PMID:25216450

  4. A comparative study of different protein immobilization methods for the construction of an efficient nano-structured lactate oxidase-SWCNT-biosensor.

    PubMed

    Pagán, Miraida; Suazo, Dámaris; Del Toro, Nicole; Griebenow, Kai

    2015-02-15

    We constructed lactate biosensors by immobilization of lactate oxidase (LOx) onto a single-walled carbon nanotube (SWCNT) electrode. The first step of the sensor construction was the immobilization of oxidized SWCNT onto a platinum electrode modified with 4-aminothiophenol (4-ATP). Two enzyme immobilization methods were used to construct the biosensors, i.e., covalent immobilization using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) and physical adsorption. Atomic force microscopy (AFM) experiments confirmed the immobilization of SWCNT during the biosensor construction and X-ray photoelectron spectroscopy (XPS) experiments confirmed covalent immobilization of LOx onto the SWCNT in the first method. The biosensor based on covalent enzyme immobilization showed a sensitivity of 5.8 μA/mM, a linearity up to 0.12 mM of L-lactate, and a detection limit of 4.0 μM. The biosensor based on protein adsorption displayed a sensitivity of 9.4 μA/mM, retaining linearity up to 0.18 mM of L-lactate with a detection limit of 3.0 μM. The difference in the biosensor response can be attributed to protein conformational or dynamical changes during covalent immobilization. The stability of the biosensors was tested at different temperatures and after different storage periods. The thermostability of the biosensors after incubation at 60 °C demonstrated that the biosensor with covalently immobilized LOx retained a higher response compared with the adsorbed protein. Long-term stability experiments show a better residual activity of 40% for the covalently immobilized protein compared to 20% of residual activity for the adsorbed protein after 25 d storage. Covalent protein immobilization was superior compared to adsorption in preserving biosensor functionality over extended time period. PMID:25216450

  5. Detergent formulations for wool domestic washings containing immobilized enzymes.

    PubMed

    Vasconcelos, Andreia; Silva, Carla J S M; Schroeder, Marc; Guebitz, Georg M; Cavaco-Paulo, Artur

    2006-05-01

    The stability of immobilized and native Esperase, a commercial serine protease, was studied by incubating the enzymes in four formulations containing the same amount of anionic and non-ionic surfactants. The results show that the activity of the immobilized enzyme is not affected by the presence of detergents while the native enzyme lost 50% of activity after 20 min of incubation in these four formulations. The washing performance of the detergents prepared with the immobilized Esperase was studied on cotton and wool fabric samples stained with human blood and egg yolk, using as control the detergent containing native Esperase. The best stain removal for cotton samples stained with human blood was achieved using the detergent with immobilized Esperase. Several physical tests confirmed that wool keratin was not degraded by the immobilized Esperase, validating the ability to use formulated detergents containing this immobilized enzyme for safe wool domestic washing. PMID:16791727

  6. An overview of technologies for immobilization of enzymes and surface analysis techniques for immobilized enzymes

    PubMed Central

    Mohamad, Nur Royhaila; Marzuki, Nur Haziqah Che; Buang, Nor Aziah; Huyop, Fahrul; Wahab, Roswanira Abdul

    2015-01-01

    The current demands of sustainable green methodologies have increased the use of enzymatic technology in industrial processes. Employment of enzyme as biocatalysts offers the benefits of mild reaction conditions, biodegradability and catalytic efficiency. The harsh conditions of industrial processes, however, increase propensity of enzyme destabilization, shortening their industrial lifespan. Consequently, the technology of enzyme immobilization provides an effective means to circumvent these concerns by enhancing enzyme catalytic properties and also simplify downstream processing and improve operational stability. There are several techniques used to immobilize the enzymes onto supports which range from reversible physical adsorption and ionic linkages, to the irreversible stable covalent bonds. Such techniques produce immobilized enzymes of varying stability due to changes in the surface microenvironment and degree of multipoint attachment. Hence, it is mandatory to obtain information about the structure of the enzyme protein following interaction with the support surface as well as interactions of the enzymes with other proteins. Characterization technologies at the nanoscale level to study enzymes immobilized on surfaces are crucial to obtain valuable qualitative and quantitative information, including morphological visualization of the immobilized enzymes. These technologies are pertinent to assess efficacy of an immobilization technique and development of future enzyme immobilization strategies. PMID:26019635

  7. Photoactive branched and linear surface architectures for functional and patterned immobilization of proteins and cells onto surfaces: a comparative study.

    PubMed

    Stegmaier, Petra; del Campo, Aránzazu

    2009-02-01

    Molecular architecture affects the properties of surface layers. Photosensitive silanes with branched architectures allow patterning and coupling of proteins and cells on surfaces while maintaining their biofunctional state. Attachment can be directed to the activated regions of irradiated substrates with high selectivity (see image of mouse fibroblasts). Novel photosensitive silanes with a branched molecular architecture combining three end-functionalized oligoethylene glycol (OEG) and alkyl arms are presented. These molecules are synthesized and applied to the modification of silica surfaces. The resulting layers are tested in their ability for the selective, patterned and functional immobilization of proteins and cells. The results demonstrate and accurately quantify the benefits of branched OEG structures against linear analogues for preventing non-specific interactions with the biological material. Linear structures guarantee high selectivity for the attachment of proteins, however, they fail in the case of cells. Branched structures provide good antifouling properties in both cases and allow the formation of protein patterns with higher densities of the target protein, as well as cell patterns. The results demonstrate the careful balance between surface functionality, composition and architecture that is required for maximizing the performance of any surface-based assay in biology. PMID:19065686

  8. Study of Immobilizing Cadmium Selenide Quantum Dots in Selected Polymers for Application in Peroxyoxalate Chemiluminescence Flow Injection Analysis

    NASA Astrophysics Data System (ADS)

    Moore, Christopher S.

    Two batches of CdSe QDs with different sizes were synthesized for immobilizing in polyisoprene (PI), polymethylmethacrylate (PMMA), and low-density polyethylene (LDPE). The combinations of QDs and polymer substrates were evaluated for their analytical fit-for-use in applicable immunoassays. Hydrogen peroxide standards were injected into the flow injection analyzer (FIA) constructed to simulate enzyme-generated hydrogen peroxide reacting with bis-(2,4,6-trichlorophenyl) oxalate. Linear correlations between hydrogen peroxide and chemiluminescent intensities yielded regression values greater than 0.9750 for hydrogen peroxide concentrations between 1.0 x 10-4 M and 1.0 x 10-1 M. The developed technique's LOD was approximately 10 ppm. Variability of the prepared QD-polymer products was as low as 3.2% throughout all preparations. Stability of the preparations was tested during a 30-day period that displayed up to a four-fold increase in the first 10 days. The preparations were decently robust to the FIA system demonstrating up to a 15.20% intensity loss after twenty repetitive injections.

  9. Biosensor studies of collagen and laminin binding with immobilized Escherichia coli O157:H7 and inhibition with naturally occurring food additives

    NASA Astrophysics Data System (ADS)

    Medina, Marjorie B.

    1999-01-01

    Escherichia coli O157:H7 outbreaks were mostly due to consumption of undercooked contaminated beef which resulted in severe illness and several fatalities. Recalls of contaminated meat are costly for the meat industry. Our research attempts to understand the mechanisms of bacterial adhesion on animal carcass in order to eliminate or reduce pathogens in foods. We have reported the interactions of immobilized E. coli O157:H7 cells with extracellular matrix (ECM) components using a surface plasmon resonance biosensor (BIAcore). These studies showed that immobilized bacterial cells allowed the study of real-time binding interactions of bacterial surface with the ECM compounds, collagen I, laminin and fibronectin. Collagen I and laminin bound to the E. coli sensor surface with dissociation and association rates ranging from 106 to 109. Binding of collagen I and laminin mixture resulted in synergistic binding signals. An inhibition model was derived using collagen-laminin as the ligand which binds with E. coli sensor. A select group of naturally occurring food additives was evaluated by determining their effectivity in inhibiting the collagen-laminin binding to the bacterial sensor. Bound collagen-laminin was detached from the E. coli sensor surface with the aid of an organic acid. The biosensor results were verified with cell aggregation assays which were observed with optical and electron microscopes. These biosensor studies provided understanding of bacterial adhesion to connective tissue macromolecules. It also provided a model system for the rapid assessment of potential inhibitors that can be used in carcass treatment to inhibit or reduce bacterial contamination.

  10. Matrix-Immobilized BMP-2 on Microcontact Printed Fibronectin as an in vitro Tool to Study BMP-Mediated Signaling and Cell Migration

    PubMed Central

    Hauff, Kristin; Zambarda, Chiara; Dietrich, Miriam; Halbig, Maria; Grab, Anna Luise; Medda, Rebecca; Cavalcanti-Adam, Elisabetta Ada

    2015-01-01

    During development, growth factors (GFs) such as bone morphogenetic proteins (BMPs) exert important functions in several tissues by regulating signaling for cell differentiation and migration. In vivo, the extracellular matrix (ECM) not only provides support for adherent cells, but also acts as reservoir of GFs. Several constituents of the ECM provide adhesive cues, which serve as binding sites for cell trans-membrane receptors, such as integrins. In conveying adhesion-mediated signaling to the intracellular compartment, integrins do not function alone but rather crosstalk and cooperate with other receptors, such as GF receptors. Here, we present a strategy for the immobilization of BMP-2 onto cellular fibronectin (cFN), a key protein of the ECM, to investigate GF-mediated signaling and migration. Following biotinylation, BMP-2 was linked to biotinylated cFN using NeutrAvidin as cross-linker. Characterization with quartz crystal microbalance with dissipation monitoring and enzyme-linked immunosorbent assay confirmed the efficient immobilization of BMP-2 on cFN over a period of 24 h. To validate the bioactivity of matrix-immobilized BMP-2 (iBMP-2), we investigated short- and long-term responses of C2C12 myoblasts, which are an established in vitro model for BMP-2 signaling, in comparison to soluble BMP-2 (sBMP-2) or in absence of GFs. Similarly to sBMP-2, iBMP-2 triggered Smad 1/5 phosphorylation and translocation of the complex to the nucleus, corresponding to the activation of BMP-mediated Smad-dependent pathway. Additionally, successful suppression of myotube formation was observed after 6 days in sBMP-2 and iBMP-2. We next implemented this approach in the fabrication of cFN micropatterned stripes by soft lithography. These stripes allowed cell-surface interaction only on the patterned cFN, since the surface in between was passivated, thus serving as platform for studies on directed cell migration. During a 10-h observation time, the migratory behavior

  11. Immobilizing Yarrowia lipolytica Lipase Lip2 via Improvement of Microspheres by Gelatin Modification.

    PubMed

    Xie, Rong; Cui, Caixia; Chen, Biqiang; Tan, Tianwei

    2015-10-01

    The purpose of this study was to investigate the feasibility of immobilizing Yarrowia lipolytica lipase lip2 on epoxy microspheres with or without gelatin modifications. The activity of lipase immobilized on gelatin-modified supports was twofold higher than those immobilized on native supports. There was no significant difference in the Michaelis-Menten constant (K M ) between the two immobilized lipases. However, lipase immobilized on gelatin modified supports showed an approximately fourfold higher V max than lipase immobilized on native supports. Lipase immobilization on the gelatin-modified support exhibited a significantly improved operational stability in an esterification system. After it was reused for a total of 35 batches, the ester conversion of lipase immobilized on gelatin-modified and native microspheres was 83 and 60 %, respectively. Furthermore, the immobilized lipase could be stored at 4 °C for 12 months without any loss of activity. PMID:26245260

  12. C-Terminal-oriented Immobilization of Enzymes Using Sortase A-mediated Technique.

    PubMed

    Hata, Yuto; Matsumoto, Takuya; Tanaka, Tsutomu; Kondo, Akihiko

    2015-10-01

    In the present study, sortase A-mediated immobilization of enzymes was used for the preparation of immobilized enzymes. Thermobifida fusca YX β-glucosidase (BGL) or Streptococcus bovis 148 α-amylase (AmyA) were produced with C-terminal sortase A recognition sequences. The resulting fusion proteins were successfully immobilized on nanoparticle surfaces using sortase A. Some properties (activity, stability, and reusability) of the immobilized fusion proteins were evaluated. Both immobilized BGL and immobilized AmyA prepared by the sortase A-mediated technique retained their catalytic activity, exhibiting activities 3.0- or 1.5-fold (respectively) of those seen with the same enzymes immobilized by chemical crosslinking. Immobilized enzymes prepared by the sortase A-mediated technique did not undergo dramatic changes in stability compared with the respective free enzymes. Thus, the sortase A-mediated technique provides a promising method for immobilization of active, stable enzymes. PMID:26098063

  13. Study of immobilized metal affinity chromatography sorbents for the analysis of peptides by on-line solid-phase extraction capillary electrophoresis-mass spectrometry.

    PubMed

    Ortiz-Martin, Lorena; Benavente, Fernando; Medina-Casanellas, Silvia; Giménez, Estela; Sanz-Nebot, Victoria

    2015-03-01

    Several commercial immobilized metal affinity chromatography sorbents were evaluated in this study for the analysis of two small peptide fragments of the amyloid β-protein (Aβ) (Aβ(1-15) and Aβ(10-20) peptides) by on-line immobilized metal affinity SPE-CE (IMA-SPE-CE). The performance of a nickel metal ion (Ni(II)) sorbent based on nitrilotriacetic acid as a chelating agent was significantly better than two copper metal ion (Cu(II)) sorbents based on iminodiacetic acid. A BGE of 25 mM phosphate (pH 7.4) and an eluent of 50 mM imidazole (in BGE) yielded a 25-fold and 5-fold decrease in the LODs by IMA-SPE-CE-UV for Aβ(1-15) and Aβ(10-20) peptides (0.1 and 0.5 μg/mL, respectively) with regard to CE-UV (2.5 μg/mL for both peptides). The phosphate BGE was also used in IMA-SPE-CE-MS, but the eluent needed to be substituted by a 0.5% HAc v/v solution. Under optimum preconcentration and detection conditions, reproducibility of peak areas and migration times was acceptable (23.2 and 12.0%RSD, respectively). The method was more sensitive for Aβ(10-20) peptide, which could be detected until 0.25 μg/mL. Linearity for Aβ(10-20) peptide was good in a narrow concentration range (0.25-2.5 μg/mL, R(2) = 0.93). Lastly, the potential of the optimized Ni(II)-IMA-SPE-CE-MS method for the analysis of amyloid peptides in biological fluids was evaluated by analyzing spiked plasma and serum samples. PMID:25640944

  14. Evaluation of two-dimensional bolus effect of immobilization/support devices on skin doses: A radiochromic EBT film dosimetry study in phantom

    SciTech Connect

    Chiu-Tsao, Sou-Tung; Chan, Maria F.

    2010-07-15

    Purpose: In this study, the authors have quantified the two-dimensional (2D) perspective of skin dose increase using EBT film dosimetry in phantom in the presence of patient immobilization devices during conventional and IMRT treatments. Methods: For 6 MV conventional photon field, the authors evaluated and quantified the 2D bolus effect on skin doses for six different common patient immobilization/support devices, including carbon fiber grid with Mylar sheet, Orfit carbon fiber base plate, balsa wood board, Styrofoam, perforated AquaPlast sheet, and alpha-cradle. For 6 and 15 MV IMRT fields, a stack of two film layers positioned above a solid phantom was exposed at the air interface or in the presence of a patient alpha-cradle. All the films were scanned and the pixel values were converted to doses based on an established calibration curve. The authors determined the 2D skin dose distributions, isodose curves, and cross-sectional profiles at the surface layers with or without the immobilization/support device. The authors also generated and compared the dose area histograms (DAHs) and dose area products from the 2D skin dose distributions. Results: In contrast with 20% relative dose [(RD) dose relative to d{sub max} on central axis] at 0.0153 cm in the film layer for 6 MV 10x10 cm{sup 2} open field, the average RDs at the same depth in the film layer were 71%, 69%, 55%, and 57% for Orfit, balsa wood, Styrofoam, and alpha-cradle, respectively. At the same depth, the RDs were 54% under a strut and 26% between neighboring struts of a carbon fiber grid with Mylar sheet, and between 34% and 56% for stretched perforated AquaPlast sheet. In the presence of the alpha-cradle for the 6 MV (15 MV) IMRT fields, the hot spot doses at the effective measurement depths of 0.0153 and 0.0459 cm were 140% and 150% (83% and 89%), respectively, of the isocenter dose. The enhancement factor was defined as the ratio of a given DAH parameter (minimum dose received in a given area) with

  15. Industrial use of immobilized enzymes.

    PubMed

    DiCosimo, Robert; McAuliffe, Joseph; Poulose, Ayrookaran J; Bohlmann, Gregory

    2013-08-01

    Although many methods for enzyme immobilization have been described in patents and publications, relatively few processes employing immobilized enzymes have been successfully commercialized. The cost of most industrial enzymes is often only a minor component in overall process economics, and in these instances, the additional costs associated with enzyme immobilization are often not justified. More commonly the benefit realized from enzyme immobilization relates to the process advantages that an immobilized catalyst offers, for example, enabling continuous production, improved stability and the absence of the biocatalyst in the product stream. The development and attributes of several established and emerging industrial applications for immobilized enzymes, including high-fructose corn syrup production, pectin hydrolysis, debittering of fruit juices, interesterification of food fats and oils, biodiesel production, and carbon dioxide capture are reviewed herein, highlighting factors that define the advantages of enzyme immobilization. PMID:23436023

  16. Determination of conformation and orientation of immobilized peptides and proteins at buried interfaces

    NASA Astrophysics Data System (ADS)

    Shen, Lei; Ulrich, Nathan W.; Mello, Charlene M.; Chen, Zhan

    2015-01-01

    Surface immobilized peptides/proteins have important applications such as antimicrobial coating and biosensing. We report a study of such peptides/proteins using sum frequency generation vibrational spectroscopy and ATR-FTIR. Immobilization on surfaces via physical adsorption and chemical coupling revealed that structures of chemically immobilized peptides are determined by immobilization sites, chemical environments, and substrate surfaces. In addition, controlling enzyme orientation by engineering the surface immobilization site demonstrated that structures can be well-correlated to measured chemical activity. This research facilitates the development of immobilized peptides/proteins with improved activities by optimizing their surface orientation and structure.

  17. Excess Weapons Plutonium Immobilization in Russia

    SciTech Connect

    Jardine, L.; Borisov, G.B.

    2000-04-15

    The joint goal of the Russian work is to establish a full-scale plutonium immobilization facility at a Russian industrial site by 2005. To achieve this requires that the necessary engineering and technical basis be developed in these Russian projects and the needed Russian approvals be obtained to conduct industrial-scale immobilization of plutonium-containing materials at a Russian industrial site by the 2005 date. This meeting and future work will provide the basis for joint decisions. Supporting R&D projects are being carried out at Russian Institutes that directly support the technical needs of Russian industrial sites to immobilize plutonium-containing materials. Special R&D on plutonium materials is also being carried out to support excess weapons disposition in Russia and the US, including nonproliferation studies of plutonium recovery from immobilization forms and accelerated radiation damage studies of the US-specified plutonium ceramic for immobilizing plutonium. This intriguing and extraordinary cooperation on certain aspects of the weapons plutonium problem is now progressing well and much work with plutonium has been completed in the past two years. Because much excellent and unique scientific and engineering technical work has now been completed in Russia in many aspects of plutonium immobilization, this meeting in St. Petersburg was both timely and necessary to summarize, review, and discuss these efforts among those who performed the actual work. The results of this meeting will help the US and Russia jointly define the future direction of the Russian plutonium immobilization program, and make it an even stronger and more integrated Russian program. The two objectives for the meeting were to: (1) Bring together the Russian organizations, experts, and managers performing the work into one place for four days to review and discuss their work with each other; and (2) Publish a meeting summary and a proceedings to compile reports of all the excellent

  18. Disposition of surplus fissile materials via immobilization

    SciTech Connect

    Gray, L.W.; Kan, T.; Sutcliffe, W.G.; McKibben, J.M.; Danker, W.

    1995-07-23

    In the Cold War aftermath, the US and Russia have agreed to large reductions in nuclear weapons. To aid in the selection of long-term management options, the USDOE has undertaken a multifaceted study to select options for storage and disposition of surplus plutonium (Pu). One disposition alternative being considered is immobilization. Immobilization is a process in which surplus Pu would be embedded in a suitable material to produce an appropriate form for ultimate disposal. To arrive at an appropriate form, we first reviewed published information on HLW immobilization technologies to identify forms to be prescreened. Surviving forms were screened using multi-attribute utility analysis to determine promising technologies for Pu immobilization. We further evaluated the most promising immobilization families to identify and seek solutions for chemical, chemical engineering, environmental, safety, and health problems; these problems remain to be solved before we can make technical decisions about the viability of using the forms for long-term disposition of Pu. All data, analyses, and reports are being provided to the DOE Office of Fissile Materials Disposition to support the Record of Decision that is anticipated in Summer of 1996.

  19. Study of Molecular Conformation and Activity-Related Properties of Lipase Immobilized onto Core-Shell Structured Polyacrylic Acid-Coated Magnetic Silica Nanocomposite Particles.

    PubMed

    Esmaeilnejad-Ahranjani, Parvaneh; Kazemeini, Mohammad; Singh, Gurvinder; Arpanaei, Ayyoob

    2016-04-01

    A facile approach for the preparation of core-shell structured poly(acrylic acid) (PAA)-coated Fe3O4 cluster@SiO2 nanocomposite particles as the support materials for the lipase immobilization is reported. Low- or high-molecular-weight (1800 and 100 000, respectively) PAA molecules were covalently attached onto the surface of amine-functionalized magnetic silica nanoacomposite particles. The successful preparation of particles were verified by scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential measurement, and Fourier-transform infrared (FTIR) techniques. Once lipase is covalently immobilized onto the particles with an average diameter of 210 ± 50 nm, resulting from high binding sites concentrations on the low- and high-molecular-weight PAA-coated particles, high lipase immobilization efficiencies (86.2% and 89.9%, respectively), and loading capacities (786 and 816 mg g(-1), respectively) are obtained. Results from circular dichroism (CD) analysis and catalytic activity tests reveal an increase in the β-sheet content of lipase molecules upon immobilization, along with an enhancement in their activities and stabilities. The lipases immobilized onto the low- and high-molecular-weight PAA-coated particles show maximum activities at 55 and 50 °C, respectively, which are ∼28% and ∼15% higher than that of the free lipase at its own optimum temperature (40 °C), respectively. The immobilized lipases exhibit excellent performance at broader temperature and pH ranges and high thermal and storage stabilities, as well as superior reusability. These prepared magnetic nanocomposite particles can be offered as suitable support materials for efficient immobilization of enzymes and improvement of the immobilized enzymes properties. PMID:26986897

  20. Immobilization of peroxidase on SPEU film via radiation grafting

    NASA Astrophysics Data System (ADS)

    Hongfei, Ha; Guanghui, Wang; Jilan, Wu

    The acrylic acid or acrylamide were grafted via radiation onto segmented polyetherurethane (SPEU) film which is a kind of biocompatible material. Then the Horse radish peroxidase was immobilized on the grafted SPEU film through chemical binding. Some quantitative relationships between the percent graft and the activity, amount of immobilized enzyme were given. The properties and application of obtained biomaterial was studied as well.

  1. The biosorption capacity of biochar for 4-bromodiphengl ether: study of its kinetics, mechanism, and use as a carrier for immobilized bacteria.

    PubMed

    Du, Jingting; Sun, Pengfei; Feng, Zhuo; Zhang, Xin; Zhao, Yuhua

    2016-02-01

    Polybrominated diphenyl ethers (PBDEs) are known as ubiquitous pollutants in ecological systems and thus pose a great threat to the health of humans and other organisms due to their bioamplification and bioaccumulation along the food chain. The present study was designed to investigate the biosorption capacity of biochar for the removal of 4-monobromodiphengl ether and its synergistic effect when used as a carrier to immobilize the 4-monobromodiphengl ether-degrading strain Sphingomonas sp. DZ3. The raw biochar material was prepared by pyrolyzing maize straw at 350 °C under oxygen-limited conditions. The maximum biosorption capacity of biochar for 4-bromodiphengl ether was determined to be 50.23 mg/L under an initial concentration of 800 mg/L at pH 7.0 and 40 °C. The data obtained from the biosorption studies were fitted successfully with the pseudo-first-order kinetic and Freundlich isotherm models. The Weber-Morris model analysis indicated that intraparticle diffusion was the limiting step in the biosorption of 4-bromodiphengl ether onto the biosorbent. The values of thermodynamic parameters △G0 were calculated as -24.61 kJ/mol (20 °C), -24.35 kJ/mol (30 °C), and -23.98 kJ/mol (40 °C), △S(0) was -8.45 kJ/mol/K, and △H(0) was 21.36 kJ/mol. The artificial neural network analysis indicated that the initial concentration appeared to be the most influential parameter on the biosorption processes. The removal rate of 4-bromodiphengl ether achieved using the biochar-microorganism system was increased by 63 and 83% compared with the rates obtained with biochar and the strain individually, respectively. The morphology of the biochar and immobilized strain was determined using a scanning electron microscope, and information of the surface functional groups of biochar was obtained through an infrared spectra study. PMID:26498816

  2. Uranium immobilization and nuclear waste

    SciTech Connect

    Duffy, C.J.; Ogard, A.E.

    1982-02-01

    Considerable information useful in nuclear waste storage can be gained by studying the conditions of uranium ore deposit formation. Further information can be gained by comparing the chemistry of uranium to nuclear fission products and other radionuclides of concern to nuclear waste disposal. Redox state appears to be the most important variable in controlling uranium solubility, especially at near neutral pH, which is characteristic of most ground water. This is probably also true of neptunium, plutonium, and technetium. Further, redox conditions that immobilize uranium should immobilize these elements. The mechanisms that have produced uranium ore bodies in the Earth's crust are somewhat less clear. At the temperatures of hydrothermal uranium deposits, equilibrium models are probably adequate, aqueous uranium (VI) being reduced and precipitated by interaction with ferrous-iron-bearing oxides and silicates. In lower temperature roll-type uranium deposits, overall equilibrium may not have been achieved. The involvement of sulfate-reducing bacteria in ore-body formation has been postulated, but is uncertain. Reduced sulfur species do, however, appear to be involved in much of the low temperature uranium precipitation. Assessment of the possibility of uranium transport in natural ground water is complicated because the system is generally not in overall equilibrium. For this reason, Eh measurements are of limited value. If a ground water is to be capable of reducing uranium, it must contain ions capable of reducing uranium both thermodynamically and kinetically. At present, the best candidates are reduced sulfur species.

  3. Effects of immobilization on spermiogenesis

    NASA Technical Reports Server (NTRS)

    Meitner, E. R.

    1980-01-01

    The influence of immobilization stress on spermiogenesis in rats was investigated. After 96 hour immobilization, histological changes began to manifest themselves in the form of practically complete disappearance of cell population of the wall of seminiferous tubule as well as a markedly increased number of cells with pathologic mitoses. Enzymological investigations showed various changes of activity (of acid and alkaline phosphatase and nonspecific esterase) in the 24, 48, and 96 hour immobilization groups.

  4. A study on the immobilization of selenium oxyanions by H 2/Pd(s) in aqueous solution . Confirmation of the one-electron reduction barrier of selenate

    NASA Astrophysics Data System (ADS)

    Puranen, Anders; Jansson, Mats; Jonsson, Mats

    2010-07-01

    Selenium is a trace element of concern in several geochemical contexts, due to the potentially high mobility of the selenium oxyanions and the narrow range between deficiency and toxicity of the element. For high level nuclear waste repositories the long-lived fission product 79Se has been identified as a potential key dose contributor for the long-term safety. This paper deals with the catalytic effect of Pd(s) on the H 2 reduction of selenium oxyanions which was studied experimentally in aqueous solutions containing bicarbonate and chloride. Pd-catalysts and hydrogen have been proposed for the remediation of various groundwater contaminants and can also serve as a model substance for catalytic noble metal inclusions present in spent nuclear fuel. In this study selenite (SeO 32-) was found to adsorb on Pd. In the presence of hydrogen the rate of selenite removal increased yielding elemental Se. However, no adsorption or reduction of selenate (SeO 42-) was observed. A simple radiation chemical experiment revealed a notable barrier towards stepwise one-electron reduction of selenate to selenite. This provides an explanation for the lower reactivity of selenate in systems where reductive immobilization of selenite as well as selenate is thermodynamically favorable.

  5. Preliminary study of the metal binding site of an anti-DTPA-indium antibody by equilibrium binding immunoassays and immobilized metal ion affinity chromatography.

    PubMed

    Boden, V; Colin, C; Barbet, J; Le Doussal, J M; Vijayalakshmi, M

    1995-01-01

    Creating metal coordination sites by modifying an existing enzyme or by eliciting antibodies against metal chelate haptens is of great interest in biotechnology to create enzyme catalysts with novel specificities. Here, we investigate the metal binding potential of a monoclonal antibody raised against a DTPA-In(III) hapten (mAb 734). We study its relative binding efficiency to metals of biological relevance by equilibrium binding immunoassays and immobilized metal ion affinity chromatography, two approaches which can give complementary information regarding composition and/or structure of the metal binding site(s). Fe(III), Fe(II), Cu(II), Mg(II), Ca(II), and Zn(II) binding was compared to In(III). All of them were shown to displace indium, but their affinity for mAb 734 decreased by 100-fold compared to indium. Competitive metal binding immunoassays between Zn(II) and In(III) revealed an unusual behavior by Zn(II) which remains to be explained. Moreover, IMAC allowed us to predict the metal binding amino acids involved in the antibody paratope. The antibody metal binding site was shown to contain at least two histidine residues in a cluster, and the presence of aspartic and glutamic acid as well as cysteine residues could not be excluded. Thus, simple competition studies allows us to obtain some partial information on the metal binding structural features of this anti-metal chelate antibody and to guide our screening of its catalytic potential. PMID:7578356

  6. Electron Tomography of Cryo-Immobilized Plant Tissue: A Novel Approach to Studying 3D Macromolecular Architecture of Mature Plant Cell Walls In Situ

    PubMed Central

    Sarkar, Purbasha; Bosneaga, Elena; Yap, Edgar G.; Das, Jyotirmoy; Tsai, Wen-Ting; Cabal, Angelo; Neuhaus, Erica; Maji, Dolonchampa; Kumar, Shailabh; Joo, Michael; Yakovlev, Sergey; Csencsits, Roseann; Yu, Zeyun; Bajaj, Chandrajit; Downing, Kenneth H.; Auer, Manfred

    2014-01-01

    Cost-effective production of lignocellulosic biofuel requires efficient breakdown of cell walls present in plant biomass to retrieve the wall polysaccharides for fermentation. In-depth knowledge of plant cell wall composition is therefore essential for improving the fuel production process. The precise spatial three-dimensional (3D) organization of cellulose, hemicellulose, pectin and lignin within plant cell walls remains unclear to date since the microscopy techniques used so far have been limited to two-dimensional, topographic or low-resolution imaging, or required isolation or chemical extraction of the cell walls. In this paper we demonstrate that by cryo-immobilizing fresh tissue, then either cryo-sectioning or freeze-substituting and resin embedding, followed by cryo- or room temperature (RT) electron tomography, respectively, we can visualize previously unseen details of plant cell wall architecture in 3D, at macromolecular resolution (∼2 nm), and in near-native state. Qualitative and quantitative analyses showed that wall organization of cryo-immobilized samples were preserved remarkably better than conventionally prepared samples that suffer substantial extraction. Lignin-less primary cell walls were well preserved in both self-pressurized rapidly frozen (SPRF), cryo-sectioned samples as well as high-pressure frozen, freeze-substituted and resin embedded (HPF-FS-resin) samples. Lignin-rich secondary cell walls appeared featureless in HPF-FS-resin sections presumably due to poor stain penetration, but their macromolecular features could be visualized in unprecedented details in our cryo-sections. While cryo-tomography of vitreous tissue sections is currently proving to be instrumental in developing 3D models of lignin-rich secondary cell walls, here we confirm that the technically easier method of RT-tomography of HPF-FS-resin sections could be used immediately for routine study of low-lignin cell walls. As a proof of principle, we characterized the

  7. Electron tomography of cryo-immobilized plant tissue: a novel approach to studying 3D macromolecular architecture of mature plant cell walls in situ.

    PubMed

    Sarkar, Purbasha; Bosneaga, Elena; Yap, Edgar G; Das, Jyotirmoy; Tsai, Wen-Ting; Cabal, Angelo; Neuhaus, Erica; Maji, Dolonchampa; Kumar, Shailabh; Joo, Michael; Yakovlev, Sergey; Csencsits, Roseann; Yu, Zeyun; Bajaj, Chandrajit; Downing, Kenneth H; Auer, Manfred

    2014-01-01

    Cost-effective production of lignocellulosic biofuel requires efficient breakdown of cell walls present in plant biomass to retrieve the wall polysaccharides for fermentation. In-depth knowledge of plant cell wall composition is therefore essential for improving the fuel production process. The precise spatial three-dimensional (3D) organization of cellulose, hemicellulose, pectin and lignin within plant cell walls remains unclear to date since the microscopy techniques used so far have been limited to two-dimensional, topographic or low-resolution imaging, or required isolation or chemical extraction of the cell walls. In this paper we demonstrate that by cryo-immobilizing fresh tissue, then either cryo-sectioning or freeze-substituting and resin embedding, followed by cryo- or room temperature (RT) electron tomography, respectively, we can visualize previously unseen details of plant cell wall architecture in 3D, at macromolecular resolution (∼ 2 nm), and in near-native state. Qualitative and quantitative analyses showed that wall organization of cryo-immobilized samples were preserved remarkably better than conventionally prepared samples that suffer substantial extraction. Lignin-less primary cell walls were well preserved in both self-pressurized rapidly frozen (SPRF), cryo-sectioned samples as well as high-pressure frozen, freeze-substituted and resin embedded (HPF-FS-resin) samples. Lignin-rich secondary cell walls appeared featureless in HPF-FS-resin sections presumably due to poor stain penetration, but their macromolecular features could be visualized in unprecedented details in our cryo-sections. While cryo-tomography of vitreous tissue sections is currently proving to be instrumental in developing 3D models of lignin-rich secondary cell walls, here we confirm that the technically easier method of RT-tomography of HPF-FS-resin sections could be used immediately for routine study of low-lignin cell walls. As a proof of principle, we characterized the

  8. IN SITU LEAD IMMOBILIZATION BY APATITE

    EPA Science Inventory

    Lead contamination is of environmental concern due to its effect on human health. he purpose of this study was to develop a technology to immobilize Pb in situ in contaminated soils and wastes using apatite. ydroxyapatite [Ca10(PO4)6(OH)2]was reacted with aqueous Pb, resinexchang...

  9. IN SITU LEAD IMMOBILIZATION BY APATITE

    EPA Science Inventory

    Lead contamination is of environmental concern due to its effect on human health. The purpose of this study was to develop a technology to immobilize Pb in situ in contaminated soils and wastes using apatite. Hydroxyapatite [Ca10(PO4)6(O...

  10. Immobilization induces nuclear accumulation of HDAC4 in rat skeletal muscle.

    PubMed

    Yoshihara, Toshinori; Machida, Shuichi; Kurosaka, Yuka; Kakigi, Ryo; Sugiura, Takao; Naito, Hisashi

    2016-07-01

    The study described herein aimed to examine changes in HDAC4 and its downstream targets in immobilization-induced rat skeletal muscle atrophy. Eleven male Wistar rats were used, and one hindlimb was immobilized in the plantar flexion position using a plaster cast. The contralateral, non-immobilized leg served as an internal control. After 10 days, the gastrocnemius muscles were removed from both hindlimbs. Ten days of immobilization resulted in a significant reduction (-27.3 %) in gastrocnemius muscle weight. A significant decrease in AMPK phosphorylation was also observed in nuclear fractions from immobilized legs relative to the controls. HDAC4 expression was significantly increased in immobilized legs in both the cytoplasmic and nuclear fractions. Moreover, Myogenin and MyoD mRNA levels were upregulated in immobilized legs, resulting in increased Atrogin-1 mRNA expression. Our data suggest that nuclear HDAC4 accumulation is partly related to immobilization-induced muscle atrophy. PMID:26759025

  11. Horseradish peroxidase and chitosan: activation, immobilization and comparative results.

    PubMed

    Mohamed, Saleh A; Al-Malki, Abdulrahman L; Kumosani, Taha A; El-Shishtawy, Reda M

    2013-09-01

    Recently, horseradish peroxidase (HRP) was immobilized on activated wool and we envisioned that the use of chitosan would be interesting instead of wool owing to its simple chemical structure, abundant nature and biodegradability. In this work, HRP was immobilized on chitosan crosslinked with cyanuric chloride. FT-IR spectroscopy and scanning electron microscopy were used to characterize immobilized HRP. The number of ten reuses of immobilized HRP has been detected. The pH was shifted from 5.5 for soluble HRP to 5.0 for immobilized enzyme. The soluble HRP had an optimum temperature of 30 °C, which was shifted to 35 °C for immobilized enzyme. The soluble HRP and immobilized HRP were thermal stable up to 35 and 45 °C, respectively. The apparent kinetic constant values (K(m)) of soluble HRP and chitosan-HRP were 35 mM and 40 mM for guaiacol and 2.73 mM and 5.7 mM for H2O2, respectively. Immobilization of HRP partially protected them from metal ions compared to soluble enzyme. The chitosan-HRP was remarkably more stable against urea, Triton X-100 and organic solvents. Chitosan-HRP exhibited large number of reuses and more resistance to harmful compounds compared with wool-HRP. On the basis of results obtained in the present study, chitosan-HRP could be employed in bioremediation application. PMID:23769933

  12. Metabolic alkalosis during immobilization in monkeys (M. nemestrina)

    NASA Technical Reports Server (NTRS)

    Young, D. R.; Yeh, I.; Swenson, R. S.

    1983-01-01

    The systemic and renal acid-base response of monkeys during ten weeks of immobilization was studied. By three weeks of immobilization, arterial pH and bicarbonate concentrations were elevated (chronic metabolic alkalosis). Net urinary acid excretion increased in immobilized animals. Urinary bicarbonate excretion decreased during the first three weeks of immobilization, and then returned to control levels. Sustained increases in urinary ammonium excretion were seen throughout the time duration of immobilization. Neither potassium depletion nor hypokalemia was observed. Most parameters returned promptly to the normal range during the first week of recovery. Factors tentatively associated with changes in acid-base status of monkeys include contraction of extracellular fluid volume, retention of bicarbonate, increased acid excretion, and possible participation of extrarenal buffers.

  13. Enzyme immobilization by means of ultrafiltration techniques.

    PubMed

    Scardi, V; Cantarella, M; Gianfreda, L; Palescandolo, R; Alfani, F; Greco, G

    1980-01-01

    Unstirred, plane membrane, ultrafiltration cells have been used as enzymatic reactor units. Because of the concentration polarization phenomena which take place in the system, at steady-state the enzyme is confined (dynamically immobilized) within an extremely narrow region upstream the ultrafiltration membrane. Correspondingly its concentration attains fairly high values. Kinetic studies have been therefore performed under quite unusual experimental conditions in order to better approximate local enzyme concentration levels in immobilized enzyme systems. Studies have been also carried out on the kinetics of enzyme deactivation in the continuous presence of substrate and reaction products. Once the enzyme concentration profile is completely developed, further injection into the system of suitable amounts of an inert proteic macromolecule (albumin polymers) gives rise to the formation of a gel layer onto the ultrafiltration membrane within which the enzyme is entrapped (statically immobilized). The effect of this immobilization technique has been studied as far as the kinetics of the main reaction, the substrate mass transfer resistances and the enzyme stability are concerned. The rejective properties of such gel layers towards enzymatic molecules have been exploited in producing multilayer, multi-enzymatic reactors. PMID:7417597

  14. Immobilization of Pb, Cd, and Zn in a contaminated soil using eggshell and banana stem amendments: metal leachability and a sequential extraction study.

    PubMed

    Ashrafi, Mehrnaz; Mohamad, Sharifah; Yusoff, Ismail; Shahul Hamid, Fauziah

    2015-01-01

    Heavy-metal-contaminated soil is one of the major environmental pollution issues all over the world. In this study, two low-cost amendments, inorganic eggshell and organic banana stem, were applied to slightly alkaline soil for the purpose of in situ immobilization of Pb, Cd, and Zn. The artificially metal-contaminated soil was treated with 5% eggshell or 10% banana stem. To simulate the rainfall conditions, a metal leaching experiment for a period of 12 weeks was designed, and the total concentrations of the metals in the leachates were determined every 2 weeks. The results from the metal leaching analysis revealed that eggshell amendment generally reduced the concentrations of Pb, Cd, and Zn in the leachates, whereas banana stem amendment was effective only on the reduction of Cd concentration in the leachates. A sequential extraction analysis was carried out at the end of the experiment to find out the speciation of the heavy metals in the amended soils. Eggshell amendment notably decreased mobility of Pb, Cd, and Zn in the soil by transforming their readily available forms to less accessible fractions. Banana stem amendment also reduced exchangeable form of Cd and increased its residual form in the soil. PMID:25060308

  15. Hydroxyl Radical Generation and DNA Nuclease Activity: A Mechanistic Study Based on a Surface-Immobilized Copper Thioether Clip-Phen Derivative.

    PubMed

    Romo, Adolfo I B; Abreu, Dieric S; de F Paulo, Tércio; Carepo, Marta S P; Sousa, Eduardo H S; Lemus, Luis; Aliaga, Carolina; Batista, Alzir A; Nascimento, Otaciro R; Abruña, Héctor D; Diógenes, Izaura C N

    2016-07-11

    Coordination compounds of copper have been invoked as major actors in processes involving the reduction of molecular oxygen, mostly with the generation of radical species the assignment for which has, so far, not been fully addressed. In the present work, we have carried out studies in solution and on surfaces to gain insights into the nature of the radical oxygen species (ROS) generated by a copper(II) coordination compound containing a thioether clip-phen derivative, 1,3-bis(1,10-phenanthrolin-2-yloxy)-N-(4-(methylthio)benzylidene)propan-2-amine (2CP-Bz-SMe), enabling its adsorption/immobilization to gold surfaces. Whereas surface plasmon resonance (SPR) and electrochemistry of the adsorbed complex indicated the formation of a dimeric Cu(I) intermediate containing molecular oxygen as a bridging ligand, scanning electrochemical microscopy (SECM) and nuclease assays pointed to the generation of a ROS species. Electron paramagnetic resonance (EPR) data reinforced such conclusions, indicating that radical production was dependent on the amount of oxygen and H2 O2 , thus pointing to a mechanism involving a Fenton-like reaction that results in the production of OH(.) . PMID:27310653

  16. Immobilization of horseradish peroxidase onto kaolin.

    PubMed

    Šekuljica, Nataša Ž; Prlainović, Nevena Ž; Jovanović, Jelena R; Stefanović, Andrea B; Djokić, Veljko R; Mijin, Dušan Ž; Knežević-Jugović, Zorica D

    2016-03-01

    Kaolin showed as a very perspective carrier for the enzyme immobilization and it was used for the adsorption of horseradish peroxidase (HRP). The effects of the enzyme concentration and pH on the immobilization efficiency were studied in the reaction with pyrogallol and anthraquinone dye C.I. Acid Violet 109 (AV 109). In addition, Fourier transform infrared spectroscopy, scanning electron microscopy and analysis by Brunauer-Emmett-Teller were performed for kaolin, thermally activated kaolin and the immobilized enzyme. It has been shown that 0.1 IU of HRP-kaolin decolorized 87 % of dye solution, under the optimal conditions (pH 5.0, temperature 24 °C, dye concentration 40 mg/L and 0.2 mM of H2O2) within 40 min. The immobilized HRP decolorization follows the Ping Pong Bi-Bi mechanism with dead-end inhibition by the dye. The biocatalyst retained 35 ± 0.9 % of the initial activity after seven cycles of reuse in the decolorization reaction of AV 109 under optimal conditions in a batch reactor. The obtained kinetic parameters and reusability study confirmed improvement in performances of k-HRP compared to free, indicating that k-HRP has a great potential for environmental purposes. PMID:26747440

  17. Potential immobilized Saccharomyces cerevisiae as heavy metal removal

    NASA Astrophysics Data System (ADS)

    Raffar, Nur Izzati Abdul; Rahman, Nadhratul Nur Ain Abdul; Alrozi, Rasyidah; Senusi, Faraziehan; Chang, Siu Hua

    2015-05-01

    Biosorption of copper ion using treated and untreated immobilized Saccharomyces cerevisiae from aqueous solution was investigate in this study. S.cerevisiae has been choosing as biosorbent due to low cost, easy and continuously available from various industries. In this study, the ability of treated and untreated immobilized S.cerevisiae in removing copper ion influence by the effect of pH solution, and initial concentration of copper ion with contact time. Besides, adsorption isotherm and kinetic model also studied. The result indicated that the copper ion uptake on treated and untreated immobilized S.cerevisiae was increased with increasing of contact time and initial concentration of copper ion. The optimum pH for copper ion uptake on untreated and treated immobilized S.cerevisiae at 4 and 6. From the data obtained of copper ion uptake, the adsorption isotherm was fitted well by Freundlich model for treated immobilized S.cerevisiae and Langmuir model for untreated immobilized S.cerevisiae according to high correlation coefficient. Meanwhile, the pseudo second order was described as suitable model present according to high correlation coefficient. Since the application of biosorption process has been received more attention from numerous researchers as a potential process to be applied in the industry, future study will be conducted to investigate the potential of immobilized S.cerevisiae in continuous process.

  18. Affinity chromatography of immobilized actin and myosin.

    PubMed Central

    Bottomley, R C; Trayer, I P

    1975-01-01

    Actin and myosin were immobilized by coupling them to agarose matrices. Both immobilized G-actin and immobilized myosin retain most of the properties of the proteins in free solution and are reliable over long periods of time. Sepharose-F-actin, under the conditions used in this study, has proved unstable and variable in its properties. Sepharose-G-actin columns were used to bind heavy meromyosin and myosin subfragment 1 specifically and reversibly. The interaction involved is sensitive to variation in ionic strength, such that myosin itself is not retained by the columns at the high salt concentration required for its complete solubilization. Myosin, rendered soluble at low ionic strength by polyalanylation, will interact successfully with the immobilized actin. The latter can distinguish between active and inactive fractions of the proteolytic and polyalanyl myosin derivatives, and was used in the preparation of these molecules. The complexes formed between the myosin derivatives and Sepharose-G-actin can be dissociated by low concentrations of ATP, ADP and pyrophosphate in both the presence and the absence of Mg2+. The G-actin columns were used to evaluate the results of chemical modifications of myosin subfragments on their interactions with actin. F-Actin in free solution is bound specifically and reversibly to columns of insolubilized myosin. Thus, with elution by either ATP or pyrophosphate, actin has been purified in one step from extracts of acetone-dried muscle powder. PMID:241335

  19. Student Collaboration in a Series of Integrated Experiments to Study Enzyme Reactor Modeling with Immobilized Cell-Based Invertase

    ERIC Educational Resources Information Center

    Taipa, M. A^ngela; Azevedo, Ana M.; Grilo, Anto´nio L.; Couto, Pedro T.; Ferreira, Filipe A. G.; Fortuna, Ana R. M.; Pinto, Ine^s F.; Santos, Rafael M.; Santos, Susana B.

    2015-01-01

    An integrative laboratory study addressing fundamentals of enzyme catalysis and their application to reactors operation and modeling is presented. Invertase, a ß-fructofuranosidase that catalyses the hydrolysis of sucrose, is used as the model enzyme at optimal conditions (pH 4.5 and 45 °C). The experimental work involves 3 h of laboratory time…

  20. Plutonium Immobilization Canister Loading

    SciTech Connect

    Hamilton, E.L.

    1999-01-26

    This disposition of excess plutonium is determined by the Surplus Plutonium Disposition Environmental Impact Statement (SPD-EIS) being prepared by the Department of Energy. The disposition method (Known as ''can in canister'') combines cans of immobilized plutonium-ceramic disks (pucks) with vitrified high-level waste produced at the SRS Defense Waste Processing Facility (DWPF). This is intended to deter proliferation by making the plutonium unattractive for recovery or theft. The envisioned process remotely installs cans containing plutonium-ceramic pucks into storage magazines. Magazines are then remotely loaded into the DWPF canister through the canister neck with a robotic arm and locked into a storage rack inside the canister, which holds seven magazines. Finally, the canister is processed through DWPF and filled with high-level waste glass, thereby surrounding the product cans. This paper covers magazine and rack development and canister loading concepts.

  1. Immobilization of Thermomyces lanuginosus Xylanase on Aluminum Hydroxide Particles Through Adsorption: Characterization of Immobilized Enzyme.

    PubMed

    Jiang, Ying; Wu, Yue; Li, Huixin

    2015-12-28

    Xylanase plays important roles in a broad range of industrial production as a biocatalyst, and its applications commonly require immobilization on supports to enhance its stability. Aluminum hydroxide, a carrier material with high surface area, has the advantages of simple and low-cost preparation and resistance to biodegradation, and can be potentially used as a proper support for xylanase immobilization. In this work, xylanase from Thermomyces lanuginosus was immobilized on two types of aluminum hydroxide particles (gibbsite and amorphous Al(OH)3) through adsorption, and the properties of the adsorbed enzymes were studied. Both particles had considerable adsorptive capacity and affinity for xylanase. Xylanase retained 75% and 64% of the original catalytic activities after adsorption to gibbsite and amorphous Al(OH)3. Both the adsorptions improved pH and thermal stability, lowered activation energy, and extended lifespan of the immobilized enzyme, as compared with the free enzyme. Xylanase adsorbed on gibbsite and amorphous Al(OH)3 retained 71% and 64% of its initial activity, respectively, after being recycled five times. These results indicated that aluminum hydroxides served as good supports for xylanase immobilization. Therefore, the adsorption of xylanase on aluminum hydroxide particles has promising potential for practical production. PMID:26282687

  2. Process development testing in support of the plutonium immobilization program

    SciTech Connect

    Herman, C; Ebbinghaus, B

    2000-02-11

    As an integral part of the plutonium disposition program, formulation and process development is being performed for the immobilization of surplus plutonium in a titanate-based ceramic. Small-scale process prototypic and lab-scale functionally prototypic equipment have been tested to help define the immobilization process. The testing has included non-radioactive surrogates and actual actinide oxides contained in the immobilized form. A summary of the process development studies, as well as the formulation studies relevant to the process, will be provided.

  3. Remote handling in the Plutonium Immobilization Project -- Second stage immobilization

    SciTech Connect

    Kriikku, E.

    1999-12-21

    The Savannah River Site (SRS) will immobilize excess plutonium in ceramic pucks and seal the pucks inside welded cans. Automated equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. Due to the radiation, remote equipment will perform these operations in a contained environment. The Plutonium Immobilization Project is in the conceptual design stage and the facility will begin operation in 2008. This paper discusses the Plutonium Immobilization Project phase 2 automation equipment conceptual design, equipment design, and work completed.

  4. SERR Spectroelectrochemical Study of Cytochrome cd1 Nitrite Reductase Co-Immobilized with Physiological Redox Partner Cytochrome c552 on Biocompatible Metal Electrodes

    PubMed Central

    Silveira, Célia M.; Quintas, Pedro O.; Moura, Isabel; Moura, José J. G.; Hildebrandt, Peter; Almeida, M. Gabriela; Todorovic, Smilja

    2015-01-01

    Cytochrome cd1 nitrite reductases (cd1NiRs) catalyze the one-electron reduction of nitrite to nitric oxide. Due to their catalytic reaction, cd1NiRs are regarded as promising components for biosensing, bioremediation and biotechnological applications. Motivated by earlier findings that catalytic activity of cd1NiR from Marinobacter hydrocarbonoclasticus (Mhcd1) depends on the presence of its physiological redox partner, cytochrome c552 (cyt c552), we show here a detailed surface enhanced resonance Raman characterization of Mhcd1 and cyt c552 attached to biocompatible electrodes in conditions which allow direct electron transfer between the conducting support and immobilized proteins. Mhcd1 and cyt c552 are co-immobilized on silver electrodes coated with self-assembled monolayers (SAMs) and the electrocatalytic activity of Ag // SAM // Mhcd1 // cyt c552 and Ag // SAM // cyt c552 // Mhcd1 constructs is tested in the presence of nitrite. Simultaneous evaluation of structural and thermodynamic properties of the immobilized proteins reveals that cyt c552 retains its native properties, while the redox potential of apparently intact Mhcd1 undergoes a ~150 mV negative shift upon adsorption. Neither of the immobilization strategies results in an active Mhcd1, reinforcing the idea that subtle and very specific interactions between Mhcd1 and cyt c552 govern efficient intermolecular electron transfer and catalytic activity of Mhcd1. PMID:26091174

  5. SERR Spectroelectrochemical Study of Cytochrome cd1 Nitrite Reductase Co-Immobilized with Physiological Redox Partner Cytochrome c552 on Biocompatible Metal Electrodes.

    PubMed

    Silveira, Célia M; Quintas, Pedro O; Moura, Isabel; Moura, José J G; Hildebrandt, Peter; Almeida, M Gabriela; Todorovic, Smilja

    2015-01-01

    Cytochrome cd1 nitrite reductases (cd1NiRs) catalyze the one-electron reduction of nitrite to nitric oxide. Due to their catalytic reaction, cd1NiRs are regarded as promising components for biosensing, bioremediation and biotechnological applications. Motivated by earlier findings that catalytic activity of cd1NiR from Marinobacter hydrocarbonoclasticus (Mhcd1) depends on the presence of its physiological redox partner, cytochrome c552 (cyt c552), we show here a detailed surface enhanced resonance Raman characterization of Mhcd1 and cyt c552 attached to biocompatible electrodes in conditions which allow direct electron transfer between the conducting support and immobilized proteins. Mhcd1 and cyt c552 are co-immobilized on silver electrodes coated with self-assembled monolayers (SAMs) and the electrocatalytic activity of Ag // SAM // Mhcd1 // cyt c552 and Ag // SAM // cyt c552 // Mhcd1 constructs is tested in the presence of nitrite. Simultaneous evaluation of structural and thermodynamic properties of the immobilized proteins reveals that cyt c552 retains its native properties, while the redox potential of apparently intact Mhcd1 undergoes a ~150 mV negative shift upon adsorption. Neither of the immobilization strategies results in an active Mhcd1, reinforcing the idea that subtle and very specific interactions between Mhcd1 and cyt c552 govern efficient intermolecular electron transfer and catalytic activity of Mhcd1. PMID:26091174

  6. Advances in ethanol production using immobilized cell systems

    SciTech Connect

    Margaritis, A.; Merchant, F.J.A.

    1984-01-01

    The application of immobilized cell systems for the production of ethanol has resulted in substantial improvements in the efficiency of the process when compared to the traditional free cell system. In this review, the various methods of cell immobilization employed in ethanol production systems have been described in detail. Their salient features, performance characteristics, advantages and limitations have been critically assessed. More recently, these immobilized cell systems have also been employed for the production of ethanol from non-conventional feedstocks such as Jerusalem artichoke extracts, cheese whey, cellulose, cellobiose and xylose. Ethanol production by immobilized yeast and bacterial cells has been attempted in various bioreactor types. Although most of these studies have been carried out using laboratory scale prototype bioreactors, it appears that only fluidized bed, horizontally packed bed bioreactors and tower fermenters may find application on scale-up. Several studies have indicated that upon immobilization, yeast cells performing ethanol fermentation exhibit more favourable physiological and metabolic properties. This, in addition to substantial improvements in ethanol productivities by immobilized cell systems, is indicative of the fact that future developments in the production of ethanol and alcoholic beverages will be directed towards the use of immobilized cell systems. 291 references.

  7. Nanoporous Gold as a Solid Support for Protein Immobilization for the Development of Immunoassays, and for Biomolecular Interaction Studies

    NASA Astrophysics Data System (ADS)

    Pandey, Binod Prasad

    Nanoporous gold (NPG) is a versatile material of high surface area to volume ratio that can be readily modified with self-assembled monolayers of alkanethiols to which biomolecules can be linked. NPG presents new opportunities for the development of immunoassays, and for the development of carbohydrate based assays. This thesis explores the use of NPG as a support for self-assembled monolayers, their linkage to antibody-enzyme conjugates for immunoassay development, and for the study and application of carbohydrate-protein interactions. Direct kinetic electrochemical immunoassays were developed on NPG for prostate specific antigen (PSA) and carcinoembryonic antigen (CEA). The decrease in enzymatic conversion of p-aminophenylphosphate to p-aminophenol, by alkaline phosphatase conjugated to an antibody, due to steric hindrance caused by the presence of antigen on antibody, was observed as a drop in peak current in square-wave voltammetry. Detection limit of these assays was 0.075 ng mL -1 and 0.015 ng mL-1 for PSA and CEA, respectively. Similarly, the linear range of determination of these biomarkers extended up to 30 ng mL-1 and 10 ng mL-1 for PSA and CEA, respectively. Minimal interference was observed using newborn calf serum as a substitute for the human serum matrix. A rapid and sensitive enzyme linked lectinsorbant assay was also developed for the study of glycoprotein-lectin interactions on the NPG surface. Self-assembled monolayers of alkanethiols on NPG were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. Similarly, the applicability of this surface for the formation of carbohydrate monolayers and its application for lectin carbohydrate interactions was also studied. Pure and mixed SAMs of 8-mercaptooctyl β-D-mannopyranoside (αMan-C8-SH) and α-D-Gal-(1→4)-β-D-Gal-(1α)-D-Glc-1-O-mercaptooctane (Gb3-C8-SH) with alkanethiols having varying tail groups were prepared. Binding affinity and binding kinetics of concanavalin A

  8. Immobilization of amyloglucosidase onto macroporous cryogels for continuous glucose production from starch.

    PubMed

    Uygun, Murat; Akduman, Begüm; Ergönül, Bülent; Aktaş Uygun, Deniz; Akgöl, Sinan; Denizli, Adil

    2015-01-01

    Poly(methyl methacrylate-glycidyl methacrylate) [Poly(MMA-GMA)] cryogels were synthesized using monomers of methylmethacrylic acid and epoxy group bearing GMA via radical cryopolymerization technique. Synthesized cryogels were used for the immobilization of amyloglucosidase to the cryogel surface using epoxy chemistry. Characterizations of the free and immobilized amyloglucosidase were carried out by comparing the optimum and kinetic parameters of enzymes. For this, pH and temperature profiles of free and immobilized preparation were studied and, it was found that, optimum pH of enzyme was not change upon immobilization (pH 5.0), while optimum temperature of the enzyme shifted 10 °C to warmer region after immobilization (optimum temperatures for free and immobilized enzyme were 55 and 65 °C, respectively). Kinetic parameters of free and immobilized enzyme were also investigated and Km values of free and immobilized amyloglucosidase were found to be 2.743 and 0.865 mg/mL, respectively. Vmax of immobilized amyloglucosidase was found to be (0.496 µmol/min) about four times less than that of free enzyme (2.020 µmol/min). Storage and operational stabilities of immobilized amyloglucosidase were also studied and it was showed that immobilized preparation had much more stability than free preparation. In the present work, amyloglucosidase immobilized poly(MMA-GMA) cryogels were used for continuous glucose syrup production from starch for the first time. Efficiency of immobilized enzyme was investigated and released amount of glucose was found to be 2.54 mg/mL at the end of the 5 min of hydrolysis. The results indicate that the epoxy functionalized cryogels offer a good alternative for amyloglucosidase immobilization applications with increased operational and thermal stability, and reusability. Also, these cryogels can be used for immobilization of other industrially valuable enzymes beyond amyloglucosidase. PMID:26235358

  9. Uranium Immobilization in Wetland Soils

    NASA Astrophysics Data System (ADS)

    Jaffe, Peter R.; Koster van Groos, Paul G.; Li, Dien; Chang, Hyun-Shik; Seaman, John C.; Kaplan, Daniel I.; Peacock, Aaron D.; Scheckel, Kirk

    2014-05-01

    In wetlands, which are a major feature at the groundwater-surface water interface, plants deliver oxygen to the subsurface to keep root tissue aerobic. Some of this oxygen leaches into the rhizosphere where it will oxidize iron that typically precipitates on or near roots. Furthermore, plans provide carbon via root exudates and turnover, which in the presence of the iron oxides drives the activity of heterotrophic iron reducers in wetland soils. Oxidized iron is an important electron acceptor for many microbially-driven transformations, which can affect the fate and transport of several pollutants. It has been shown that heterotrophic iron reducing organisms, such as Geobacter sp., can reduce water soluble U(VI) to insoluble U(IV). The goal of this study was to determine if and how iron cycling in the wetland rhizosphere affects uranium dynamics. For this purpose, we operated a series of small-scale wetland mesocosms in a greenhouse to simulate the discharge of uranium-contaminated groundwater to surface waters. The mesocosms were operated with two different Fe(II) loading rates, two plant types, and unplanted controls. The mesocosms contained zones of root exclusion to differentiate between the direct presence and absence of roots in the planted mesocosms. The mesocosms were operated for several month to get fully established, after which a U(VI) solution was fed for 80 days. The mesocosms were then sacrificed and analyzed for solid-associated chemical species, microbiological characterization, micro-X-ray florescence (µ-XRF) mapping of Fe and U on the root surface, and U speciation via X-ray Absorption Near Edge Structure (XANES). Results showed that bacterial numbers including Geobacter sp., Fe(III), as well as total uranium, were highest on roots, followed by sediments near roots, and lowest in zones without much root influence. Results from the µ-XRF mapping on root surfaces indicated a strong spatial correlation between Fe and U. This correlation was

  10. Antimony (Sb) and lead (Pb) in contaminated shooting range soils: Sb and Pb mobility and immobilization by iron based sorbents, a field study.

    PubMed

    Okkenhaug, Gudny; Grasshorn Gebhardt, Karl-Alexander; Amstaetter, Katja; Bue, Helga Lassen; Herzel, Hannes; Mariussen, Espen; Rossebø Almås, Åsgeir; Cornelissen, Gerard; Breedveld, Gijs D; Rasmussen, Grete; Mulder, Jan

    2016-04-15

    Small-arm shooting ranges often receive a significant input of lead (Pb), copper (Cu) and antimony (Sb) from ammunition. The goal of the present study was to investigate the mobility, distribution and speciation of Pb and Sb pollution under field conditions in both untreated and sorbent-amended shooting range soil. Elevated Sb (19-349μgL(-1)) and Pb (7-1495μgPbL(-1)) concentrations in the porewater of untreated soil over the four-year test period indicated a long-term Sb and Pb source to the adjacent environment in the absence of remedial measures. Mixing ferric oxyhydroxide powder (CFH-12) (2%) together with limestone (1%) into the soil resulted in an average decrease of Sb and Pb porewater concentrations of 66% and 97%, respectively. A similar reduction was achieved by adding 2% zerovalent iron (Fe°) to the soil. The remediation effect was stable over the four-year experimental period indicating no remobilization. Water- and 1M NH4NO3-extractable levels of Sb and Pb in field soil samples indicated significant immobilization by both treatments (89-90% for Sb and 89-99% for Pb). Results from sequential extraction analysis indicate fixation of Sb and Pb in less accessible fractions like amorphous iron oxides or even more crystalline and residual mineral phases, respectively. This work shows that amendment with Fe-based sorbents can be an effective method to reduce the mobility of metals both in cationic and anionic form in polluted shooting range soil. PMID:26799225

  11. FTIR and Mössbauer spectroscopic study of sodium-aluminum-iron phosphate glassy materials for high level waste immobilization

    NASA Astrophysics Data System (ADS)

    Stefanovsky, S. V.; Stefanovsky, O. I.; Remizov, M. B.; Belanova, E. A.; Kozlov, P. V.; Glazkova, Ya. S.; Sobolev, A. V.; Presniakov, I. A.; Kalmykov, S. N.; Myasoedov, B. F.

    2015-11-01

    Complex sodium-aluminum-iron phosphate glassy materials with various Al2O3 to Fe2O3 ratio containing high level waste (HLW) surrogate were characterized by X-ray diffraction and scanning electron microscopy and studied in details by Fourier transform infrared (FTIR) spectroscopy. The samples with high Al2O3 content and not containing Fe2O3 were predominantly amorphous but subjected to devitrification under annealing. Addition of B2O3 and partial Fe2O3 substitution for Al2O3 in the materials increases their resistance to devitrification whereas further substitution and NiO incorporation significantly increase the tendency to devitrification. FTIR spectra demonstrate changes in the structure of glassy materials caused by both structural variations in the anionic motif and occurrence of crystalline phases in the materials. According to Mössbauer spectroscopy data, iron in the glassy samples is present as octahedrally coordinated Fe3+ ions while in the partly devitrified samples iron is partitioned among vitreous and crystalline phases entering the vitreous phase mainly as Fe3+O6 units and crystalline phases as major Fe3+ and minor Fe2+ ions in a magnetically ordered state and participating in a "fast" electronic exchange.

  12. Waste immobilization process development at the Savannah River Plant

    SciTech Connect

    Charlesworth, D L

    1986-01-01

    Processes to immobilize various wasteforms, including waste salt solution, transuranic waste, and low-level incinerator ash, are being developed. Wasteform characteristics, process and equipment details, and results from field/pilot tests and mathematical modeling studies are discussed.

  13. N-15 NMR study of the immobilization of 2,4- and 2,6-dinitrotoluene in aerobic compost

    USGS Publications Warehouse

    Thorn, K.A.; Pennington, J.C.; Kennedy, K.R.; Cox, L.G.; Hayes, C.A.; Porter, B.E.

    2008-01-01

    Large-scale aerobic windrow composting has been used to bioremediate washout lagoon soils contaminated with the explosives TNT (2,4,6- trinitrotoluene) and RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) at several sites within the United States. We previously used 15N NMR to investigate the reduction and binding of T15NT in aerobic bench -scale reactors simulating the conditions of windrow composting. These studies have been extended to 2,4-dinitrotoluene (2,4DNT) and 2,6-dinitrotoluene (2,6DNT), which, as impurities in TNT, are usually present wherever soils have been contaminated with TNT. Liquid-state 15N NMR analyses of laboratory reactions between 4-methyl-3-nitroaniline-15N, the major monoamine reduction product of 2,4DNT, and the Elliot soil humic acid, both in the presence and absence of horseradish peroxidase, indicated that the amine underwent covalent binding with quinone and other carbonyl groups in the soil humic acid to form both heterocyclic and non-heterocyclic condensation products. Liquid-state 15N NMR analyses of the methanol extracts of 20 day aerobic bench-scale composts of 2,4-di-15N-nitrotoluene and 2,6-di-15N-nitrotoluene revealed the presence of nitrite and monoamine, but not diamine, reduction products, indicating the occurrence of both dioxygenase enzyme and reductive degradation pathways. Solid-state CP/MAS 15N NMR analyses of the whole composts, however, suggested that reduction to monoamines followed by covalent binding of the amines to organic matter was the predominant pathway. ?? 2008 American Chemical Society.

  14. Skeletal muscle HSP expression in response to immobilization and remobilization.

    PubMed

    Venojärvi, M; Kvist, M; Jozsa, L; Kalimo, H; Hänninen, O; Atalay, M

    2007-04-01

    Heat shock proteins play an important regulatory role in the cellular defence. Oxidative stress is one of the factors inducing heat shock protein expression. This study tested the effects of 4 weeks of immobilization and subsequent remobilization on heat shock protein expression and oxidative stress in the lateral gastrocnemius and plantaris muscles of the rat. Active mobilization or free mobilization protocols were used for remobilization. In active mobilization, strenuous uphill treadmill running, twice a day, was started immediately after the immobilization and lasted for six days. Rats in the free mobilization group moved freely in their cages immediately after the immobilization. Expression of heat shock proteins was upregulated during the recovery from immobilization, especially in the lateral gastrocnemius muscle in the active mobilization group. However, markers of oxidative stress, such as protein carbonyls and 4-hydroxynonenal protein adducts, or activities of the antioxidant enzymes glutathione peroxidase and glutathione reductase, did not change after the immobilization and subsequent recovery. In summary, following immobilization, both intensive and spontaneous exercise upregulated the heat shock protein expressions in the lateral gastrocnemius muscle and partly in the plantaris muscle, which may contribute to the recovery from immobilization atrophy. PMID:17024631

  15. Acetylcholinesterase immobilized onto PEI-coated silica nanoparticles.

    PubMed

    Tumturk, Hayrettin; Yüksekdag, Hazer

    2016-01-01

    Polyethyleneimine (PEI) coated-silica nanoparticles were prepared by the Stöber method. The formation and the structure of the nanoparticles were characterized by ATR-FT-IR spectroscopy and transmission electron microscopy (TEM). TEM images of the silica and PEI-coated nanoparticles revealed that they were well dispersed and that there was no agglomeration. The acetylcholineesterase enzyme was immobilized onto these nanoparticles. The effects of pH and temperature on the storage stability of the free and immobilized enzyme were investigated. The optimum pHs for free and immobilized enzymes were determined as 7.0 and 8.0, respectively. The optimum temperatures for free and immobilized enzymes were found to be 30.0 and 35.0°C, respectively. The maximum reaction rate (Vmax) and the Michaelis-Menten constant (Km) were investigated for the free and immobilized enzyme. The storage stability of acetylcholinesterase was increased when immobilized onto the novel PEI-coated silica nanoparticles. The reuse numbers of immobilized enzyme were also studied. These hybrid nanoparticles are desirable as carriers for biomedical applications. PMID:25365355

  16. Remobilization does not fully restore immobilization induced articular cartilage atrophy.

    PubMed

    Haapala, J; Arokoski, J P; Hyttinen, M M; Lammi, M; Tammi, M; Kovanen, V; Helminen, H J; Kiviranta, I

    1999-05-01

    The recovery of articular cartilage from immobilization induced atrophy was studied. The right hind limbs of 29-week-old beagle dogs were immobilized for 11 weeks and then remobilized for 50 weeks. Cartilage from the immobilized knee was compared with tissue from age matched control animals. After the immobilization period, uncalcified articular cartilage glycosaminoglycan concentration was reduced by 20% to 23%, the reduction being largest (44%) in the superficial zone. The collagen fibril network showed no significant changes, but the amount of collagen crosslinks was reduced (13.5%) during immobilization. After remobilization, glycosaminoglycan concentration was restored at most sites, except for in the upper parts of uncalcified cartilage in the medial femoral and tibial condyles (9% to 17% less glycosaminoglycans than in controls). The incorporation of 35SO4 was not changed, and remobilization also did not alter the birefringence of collagen fibrils. Remobilization restored the proportion of collagen crosslinks to the control level. The changes induced by joint unloading were reversible at most sites investigated, but full restoration of articular cartilage glycosaminoglycan concentration was not obtained in all sites, even after remobilization for 50 weeks. This suggests that lengthy immobilization of a joint can cause long lasting articular cartilage proteoglycan alterations at the same time as collagen organization remains largely unchanged. Because proteoglycans exert strong influence on the biomechanical properties of cartilage, lengthy immobilization may jeopardize the well being of articular cartilage. PMID:10335301

  17. Enhanced growth of lactobacilli in soymilk upon immobilization on agrowastes.

    PubMed

    Teh, Sue-Siang; Ahmad, Rosma; Wan-Abdullah, Wan-Nadiah; Liong, Min-Tze

    2010-04-01

    Cell immobilization is an alternative to microencapsulation for the maintenance of cells in a liquid medium. The objective of this study was to evaluate the effects of agrowastes from durian (Durio zibethinus), cempedak (Artocarpus champeden), and mangosteen (Garcinia mangostana) as immobilizers for lactobacilli grown in soymilk. Rinds from the agrowastes were separated from the skin, dried, and ground (150 microm) to form powders and used as immobilizers. Scanning electron microscopy revealed that lactobacilli cells were attached and bound to the surface of the immobilizers. Immobilized cells of Lactobacillus acidophilus FTDC 1331, L. acidophilus FTDC 2631, L. acidophilus FTDC 2333, L. acidophilus FTDC 1733, and L. bulgaricus FTCC 0411 were inoculated into soymilk, stored at room temperature (25 degrees C) and growth properties were evaluated over 168 h. Soymilk inoculated with nonimmobilized cells was used as the control. Utilization of substrates, concentrations of lactic and acetic acids, and changes in pH were evaluated in soymilk over 186 h. Immobilized lactobacilli showed significantly better growth (P < 0.05) compared to the control, accompanied by higher production of lactic and acetic acids in soymilk. Soymilk containing immobilized cells showed greater reduction of soy sugars such as stachyose, raffinose, sucrose, fructose, and glucose compared to the control (P < 0.05). PMID:20492305

  18. Stability of soybean oil degumming using immobilized phospholipase A(2).

    PubMed

    Yu, Dianyu; Ma, Ying; Jiang, Lianzhou; Walid, Elfalleh; He, Shenghua; He, Yanming; Xiaoyu, Zhou; Zhang, Jianing; Hu, Lizhi

    2014-01-01

    The aim of this study was evaluation of stability of immobilized phospholipase A2 (PLA2) for soybean oil degumming. Also, the effect of reaction time on residual phosphorus levels was investigated according to the optimum pH and temperature. The free PLA2 and three immobilized PLA2 demonstrated significant differences in optimum operation conditions. pH, temperature and reaction time increased upon immobilization for three different immobilized PLA2 (PLA2-CA, PLA2-CAC and PLA2-CAG). Immobilized PLA2 showed enhanced thermal stability and retained more than 74% of relative activity after 1 h of incubation at 60°C, while the free PLA2 retained only 33%. The three immobilized PLA2 retained 30% to 60% of initial activities after 7 recycles. In particular, PLA2-CAC has more significant profiles in pH, temperature, reaction time and showed the highest remaining activity, thermal stability, reusability. Therefore, PLA2-CAC is a suitable immobilized enzyme for soybean oil degumming process. PMID:24371193

  19. Polymer-assisted iron oxide magnetic nanoparticle immobilized keratinase

    NASA Astrophysics Data System (ADS)

    Konwarh, Rocktotpal; Karak, Niranjan; Rai, Sudhir Kumar; Mukherjee, Ashis Kumar

    2009-06-01

    Nanotechnology holds the prospect for avant-garde changes to improve the performance of materials in various sectors. The domain of enzyme biotechnology is no exception. Immobilization of industrially important enzymes onto nanomaterials, with improved performance, would pave the way to myriad application-based commercialization. Keratinase produced by Bacillus subtilis was immobilized onto poly(ethylene glycol)-supported Fe3O4 superparamagnetic nanoparticles. The optimization process showed that the highest enzyme activity was noted when immobilized onto cyanamide-activated PEG-assisted MNP prepared under conditions of 25 °C and pH 7.2 of the reaction mixture before addition of H2O2 (3% w/w), 2% (w/v) PEG6000 and 0.062:1 molar ratio of PEG to FeCl2·4H2O. Further statistical optimization using response surface methodology yielded an R2 value that could explain more than 94% of the sample variations. Along with the magnetization studies, the immobilization of the enzyme onto the PEG-assisted MNP was characterized by UV, XRD, FTIR and TEM. The immobilization process had resulted in an almost fourfold increase in the enzyme activity over the free enzyme. Furthermore, the immobilized enzyme exhibited a significant thermostability, storage stability and recyclability. The leather-industry-oriented application of the immobilized enzyme was tested for the dehairing of goat-skin.

  20. Enhanced stability of catalase covalently immobilized on functionalized titania submicrospheres.

    PubMed

    Wu, Hong; Liang, Yanpeng; Shi, Jiafu; Wang, Xiaoli; Yang, Dong; Jiang, Zhongyi

    2013-04-01

    In this study, a novel approach combing the chelation and covalent binding was explored for facile and efficient enzyme immobilization. The unique capability of titania to chelate with catecholic derivatives at ambient conditions was utilized for titania surface functionalization. The functionalized titania was then used for enzyme immobilization. Titania submicrospheres (500-600 nm) were synthesized by a modified sol-gel method and functionalized with carboxylic acid groups through a facile chelation method by using 3-(3,4-dihydroxyphenyl) propionic acid as the chelating agent. Then, catalase (CAT) was covalently immobilized on these functionalized titania submicrospheres through 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) coupling reaction. The immobilized CAT retained 65% of its free form activity with a loading capacity of 100-150 mg/g titania. The pH stability, thermostability, recycling stability and storage stability of the immobilized CAT were evaluated. A remarkable enhancement in enzyme stability was achieved. The immobilized CAT retained 90% and 76% of its initial activity after 10 and 16 successive cycles of decomposition of hydrogen peroxide, respectively. Both the Km and the Vmax values of the immobilized CAT (27.4 mM, 13.36 mM/min) were close to those of the free CAT (25.7 mM, 13.46 mM/min). PMID:23827593

  1. Immunosuppressive agent leflunomide: a SWNTs-immobilized dihydroortate dehydrogenase inhibitory effect and computational study of its adsorption properties on zigzag single walled (6,0) carbon and boron nitride nanotubes as controlled drug delivery devices.

    PubMed

    Raissi, Heidar; Mollania, Fariba

    2014-06-01

    Leflunomide [HWA 486 or RS-34821, 5-methyl-N-(4trifluoromethylphenyl)-4-isoxazole carboximide] is an immunosuppressive agent effective in the treatment of rheumatoid arthritis. Dihydroortate dehydrogenase (DHODH, EC 1.3.3.1) immobilization on the nanotubes was carried out and biochemical characterization of free and immobilized enzyme was determined. In comparison with free enzyme, the immobilized DHODH showed improved stability and reusability for investigation of inhibition pattern of drugs such as leflunomide. The experimental data showed that, DHODH was inhibited by the active metabolite of leflunomide (RS-61980) with a Ki and KI of 0.82 and 0.06 mM, respectively. Results exhibited mixed-type inhibition kinetics towards dihydroorotate as a substrate in the free and immobilized enzyme. Furthermore, the behavior of anticancer drug leflunomide adsorbed on the external surface of zigzag single walled (6,0) carbon and boron nitride nanotubes (SWCNT and SWBNNT) was studied by means of DFT calculations at the B3LYP/6-31G(*) level of theory. The larger adsorption energies and charges transfer showed that the adsorption of leflunomide onto SWBNNT is more stable than that the adsorption of leflunomide onto SWCNT. Frontier molecular orbitals (HOMO and LUMO) suggest that adsorption of leflunomide onto SWBNNT behave as charge transfer compounds with leflunomide as an electron donor and SWBNNT as an electron acceptor. Thus, nanotubes (NTs) have been proposed and actively explored as multipurpose innovative carriers for drug delivery and diagnostic application. The AIM theory has been also applied to analyze the properties of the bond critical points: their electron densities and their laplacians. Also, the natural bond orbital (NBO) calculations were performed to derive natural atomic orbital occupancies, and partial charges of the interacting atoms in the equilibrium tube-molecule distance. PMID:24566615

  2. Treating Wastewater With Immobilized Enzymes

    NASA Technical Reports Server (NTRS)

    Jolly, Clifford D.

    1991-01-01

    Experiments show enzymes are immobilized on supporting materials to make biocatalyst beds for treatment of wastewater. With suitable combination of enzymes, concentrations of various inorganic and organic contaminants, including ammonia and urea, reduced significantly.

  3. Immobilized enzymes affect biofilm formation.

    PubMed

    Cordeiro, Ana L; Hippius, Catharina; Werner, Carsten

    2011-09-01

    The effect of the activity of immobilized enzymes on the initial attachment of pathogenic bacteria commonly associated with nosocomial infections (Pseudomonas aeruginosa and Staphylococcus epidermidis) was investigated. The proteolytic enzymes, subtilisin A and the glycoside hydrolase cellulose, were covalently attached onto poly(ethylene-alt-maleic) anhydride copolymer films. A comparison between active and heat-inactivated surfaces showed that while the activity of immobilized cellulase reduced the attachment of S. epidermidis by 67%, it had no effect on the attachment of P. aeruginosa. Immobilized subtilisin A had opposite effects: the active enzyme had no effect on the attachment of S. epidermidis but reduced the attachment of P. aeruginosa by 44%. The results suggest that different biomolecules are involved in the initial steps of attachment of different bacteria, and that the development of broad-spectrum antifouling enzymatic coatings will need to involve the co-immobilization of enzymes. PMID:21618024

  4. High-level-waste immobilization

    SciTech Connect

    Crandall, J L

    1982-01-01

    Analysis of risks, environmental effects, process feasibility, and costs for disposal of immobilized high-level wastes in geologic repositories indicates that the disposal system safety has a low sensitivity to the choice of the waste disposal form.

  5. Optimizing immobilization of avidin on surface-modified magnetic nanoparticles: characterization and application of protein-immobilized nanoparticles.

    PubMed

    Yang, Tao; Sun, Shuguo; Ma, Meihu; Lin, Qinlu; Zhang, Lin; Li, Yan; Luo, Feijun

    2015-10-01

    A simple optimization method of immobilization of avidin on magnetic nanoparticles (MNPs)' surface was proposed in this study. The avidin-immobilized MNPs were then developed and used to immobilize a model enzyme [Horseradish peroxidase (HRP)]. The loading capacity (LC) and activity of avidin-immobilized MNPs were optimized through selecting the most appropriate nanoparticle's size and shape, glutaraldehyde concentration, cross-linking reaction time, ultrasonic processing time, and initial concentration of avidin. The LC under optimized conditions was 63.37 ± 1.29 mg avidin/g MNPs, and the immobilized protein was still able to maintain its high biological activity of 10.86 ± 0.13 U/mg (biotin-binding activity of nature avidin was 14.1 U/mg) and better thermal stability compared to free avidin. A highly reusable, stable, and easily recovered immobilized HRP was obtained using MNPs as carriers. The immobilized HRP was reused repeatedly more than 9 times and retained more than 65 % of its original activity. PMID:26224655

  6. Development and characterization of beta-secretase monolithic micro-immobilized enzyme reactor for on-line high-performance liquid chromatography studies.

    PubMed

    Mancini, Francesca; Naldi, Marina; Cavrini, Vanni; Andrisano, Vincenza

    2007-12-21

    beta-Site APP cleavage enzyme 1 (BACE-1) is a transmembrane aspartyl protease that cleaves the amyloid-beta precursor protein (APP), which is abundant in neurons. BACE-1 is required for the generation of amyloid-beta (Abeta) peptides implicated in the pathogenesis of Alzheimer's disease (AD). It is widely believed that halting the production of Abeta peptide, by inhibition of BACE-1, is an attractive therapeutic modality for the treatment of Alzheimer's disease. BACE-1 has never been immobilized before. In the present study, for the first time, human recombinant beta-secretase micro-immobilised enzyme reactor (hrBACE-1-micro-IMER) was prepared by using an in situ immobilisation procedure on an ethylendiamine monolithic convective interaction media (EDA-CIM) disk. The activity and kinetic parameters of the hrBACE-1-micro-IMER were investigated by insertion in a HPLC system with fluorescent and mass detection. The micro-IMER was characterized in terms of units of immobilised hrBACE-1 and best mobile phase conditions for activity, by using as substrate casein-FITC and JMV2236, a peptide mimicking the Swedish-mutated APP (amyloid precursor protein) sequence. The characterization of the hrBACE-1-micro-IMER in terms of number of enzymatic active units after covalent linking to the solid matrix was performed by using the JMV2236 peptide as substrate in a HPLC-MS system. JMV2236 was injected into the hrBACE-1-micro-IMER and enzymatically cleaved; the product of the enzymatic cleavage and the remaining non-cleaved substrate were collected on a C18 column trap and switched to the LC-electrospray ionization MS system for kinetic constants determination. Inhibition studies were carried out. The effect of donepezil and pepstatin A, as BACE-1 inhibitors, was evaluated by simultaneous injection of the compounds with the peptidic substrate. The relative IC(50) values were found in agreement with that derived by the conventional fluorescence method, confirming the applicability of

  7. Immobilized cells in meat fermentation.

    PubMed

    McLoughlin, A J; Champagne, C P

    1994-01-01

    The immobilization of microbial cells can contribute to fermented meat technology at two basic levels. First, the solid/semisolid nature (low available water) of the substrate restricts the mobility of cells and results in spatial organizations based on "natural immobilization" within the fermentation matrix. The microniches formed influence the fermentation biochemistry through mass transfer limitations and the subsequent development and activity of the microflora. This form of immobilization controls the nature of competition between subpopulations within the microflora and ultimately exerts an effect on the ecological competence (ability to survive and compete) of the various cultures present. Second, immobilized cell technology (ICT) can be used to enhance the ecological competence of starter cultures added to initiate the fermentation. Immobilization matrices such as alginate can provide microniches or microenvironments that protect the culture during freezing or lyophilization, during subsequent rehydration, and when in competition with indigenous microflora. The regulated release of cells from the microenvironments can also contribute to competitive ability. The regulation of both immobilization processes can result in enhanced fermentation activity. PMID:8069934

  8. Immobilization of Polymeric Luminophor on Nanoparticles Surface

    NASA Astrophysics Data System (ADS)

    Bolbukh, Yuliia; Podkoscielna, Beata; Lipke, Agnieszka; Bartnicki, Andrzej; Gawdzik, Barbara; Tertykh, Valentin

    2016-04-01

    Polymeric luminophors with reduced toxicity are of the priorities in the production of lighting devices, sensors, detectors, bioassays or diagnostic systems. The aim of this study was to develop a method of immobilization of the new luminophor on a surface of nanoparticles and investigation of the structure of the grafted layer. Monomer 2,7-(2-hydroxy-3-methacryloyloxypropoxy)naphthalene (2,7-NAF.DM) with luminophoric properties was immobilized on silica and carbon nanotubes in two ways: mechanical mixing with previously obtained polymer and by in situ oligomerization with chemisorption after carrier's modification with vinyl groups. The attached polymeric (or oligomeric) surface layer was studied using thermal and spectral techniques. Obtained results confirm the chemisorption of luminophor on the nanotubes and silica nanoparticles at the elaborated synthesis techniques. The microstructure of 2,7-NAF.DM molecules after chemisorption was found to be not changed. The elaborated modification approach allows one to obtain nanoparticles uniformly covered with polymeric luminophor.

  9. Summary report on geochemical barrier special study. [Geochemically modify tailings to immobilize contaminants with modifiers such as peat, limestone, and hydrated lime

    SciTech Connect

    Not Available

    1988-12-01

    Long-term management of uranium mill tailings must provide assurance that soluble contaminants will not migrate beyond the Point of Compliance. Conventional management alternatives provide containment through the use of physical barriers which are designed to prevent migration of water through the tailings pile. An alternative is to geochemically modify the tailings to immobilize the contaminants. This investigation examined three potential geochemical modifiers to determine their ability to immobilize inorganic groundwater contaminants found in uranium mill tailings. These modifiers were hydrated lime (Ca(OH)[sub 2]), limestone (CaCO[sub 3]), and a sphaegnum peat moss. This investigation focused on both the geochemical interactions between the tailings and the modifiers, and the effects the modifiers had on the physical strength of the tailings. The geochemical investigations began with characterization of the tailings by X-ray diffraction and scanning electron microscopy. This was followed by batch leaching experiments in which various concentrations of each modifier were added to tailings in shaker flasks and allowed to come to equilibrium. Finally, column experiments were conducted to simulate flow through a tailings pile. The results show that all of the modifiers were at least moderately effective at immobilizing most of the groundwater contaminants of concern at uranium mill tailings sites. Hydrated lime was able to achieve 90 percent concentration reduction of arsenic, cadmium, selenium, uranium, and sulfate when added at a two percent concentration. Limestone was somewhat less effective and peat removed greater than 90 percent of arsenic, lead, uranium, and sulfate at a one percent concentration. The column tests showed that kinetic and/or mass transfer limitations are important and that sufficient time must be allowed for the immobilization reactions to occur.

  10. A regenerable ruthenium tetraammine nitrosyl complex immobilized on a modified silica gel surface: preparation and studies of nitric oxide release and nitrite-to-NO conversion.

    PubMed

    Doro, Fabio Gorzoni; Rodrigues-Filho, Ubirajara P; Tfouni, E

    2007-03-15

    Silica gel bearing isonicotinamide groups was prepared by further modification of 3-aminopropyl-functionalized silica by a reaction with isonicotinic acid and 1,3-dicyclohexylcarbodiimide to yield 3-isonicotinamidepropyl-functionalized silica gel (ISNPS). This support was characterized by means of infrared spectroscopy, elemental analysis, and specific surface area. The ISNPS was used to immobilize the [Ru(NH(3))(4)SO(3)] moiety by reaction with trans-[Ru(NH(3))(4)(SO(2))Cl]Cl, yielding [Si(CH(2))(3)(isn)Ru(NH(3))(4)(SO(3))]. The related immobilized [Si(CH(2))(3)(isn)Ru(NH(3))(4)(L)](3+/2+) (L=SO(2), SO(2-)(4), OH(2), and NO) complexes were prepared and characterized by means of UV-vis and IR spectroscopy, as well as by cyclic voltammetry. Syntheses of the nitrosyl complex were performed by reaction of the immobilized ruthenium ammine [Si(CH(2))(3)(isn)Ru(NH(3))(4)(OH(2))](2+) with nitrite in acid or neutral (pH 7.4) solution. The similar results obtained in both ways indicate that the aqua complex was able to convert nitrite into coordinated nitrosyl. The reactivity of [Si(CH(2))(3)(isn)Ru(NH(3))(4)(NO)](3+) was investigated in order to evaluate the nitric oxide (NO) release. It was found that, upon light irradiation or chemical reduction, the immobilized nitrosyl complex was able to release NO, generating the corresponding Ru(III) or Ru(II) aqua complexes, respectively. The NO material could be regenerated from these NO-depleted materials obtained photochemically or by reduction. Regeneration was done by reaction with nitrite in aqueous solution (pH 7.4). Reduction-regeneration cycles were performed up to three times with no significant leaching of the ruthenium complex. PMID:17196216

  11. The Collaborative Study on the Enzymatic Analysis of Positional Distribution of Short- and Medium-chain Fatty Acids in Milk Fat Using Immobilized Candida antarctica Lipase B.

    PubMed

    Yoshinaga, Kazuaki; Sato, Shinichi; Sasaki, Ryo; Asada, Mihoko; Hori, Ryuji; Imagi, Jun; Miyazaki, Yosuke; Nagai, Toshiharu; Saito, Katsuyoshi; Sano, Takashi; Sasaki, Akiko; Sato, Chiemi; Tsukahara, Yuki; Yamashita, Atsushi; Watanabe, Shimpei; Watanabe, Yomi

    2016-01-01

    The positional distributions of fatty acids (FAs) in milk fat containing short- and medium-chain FAs were analyzed by sn-1(3)-selective transesterification of triacylglycerols (TAGs) with ethanol using immobilized Candida antarctica lipase B (CALB), in a collaborative study conducted by 10 laboratories. The mean C4:0, C6:0, and C8:0 FA contents, when analyzed as propyl esters (PEs) using gas chromatography (GC) with a DB-23 capillary column, were found to be 3.0, 2.0, and, 1.3 area%, respectively. Their reproducibility standard deviations were 0.33, 0.18, and 0.19, respectively. The mean C4:0, C6:0, and C8:0 contents at the sn-2 position were 0.3, 0.4, and 1.0 area%, respectively. Their reproducibility standard deviations were 0.17, 0.11, and 0.19, respectively. The reproducibility standard deviations of C4:0, C6:0, and C8:0 FAs at the sn-2 position were either the same as or smaller than those for milk fat, although the FA contents at the sn-2 position were smaller than those in the milk fat. Therefore, it was concluded that the CALB method for estimating the regiospecific distribution is applicable to TAGs containing short- and medium-chain FAs. When estimating the short-chain (SC) FA contents in fats and oils by GC, it is better to analyze SCFAs as PEs or butyl esters, and not as methyl esters, in order to prevent loss of SCFAs during the experimental procedure because of their volatility and water solubility. This study also revealed that the stationary phase of the GC capillary column affected the flame ionization detector (FID) response of SCFAs. The theoretical FID correction factor (MWFA / active carbon number / atomic weight of carbon) fitted well with the actual FID responses of C4:0-C12:0 FAs when they were analyzed as PEs using a DB-23 column; however, this was not the case when the GC analysis was performed using wax-type columns. PMID:26972465

  12. Cellulase immobilized on modified nylon for saccharification of cellulose

    SciTech Connect

    Jain, P.; Wilkins, E.S.

    1987-01-01

    The present study deals with the immobilization of cellulase on nylon and nylon incorporated with glass. The immobilized and free enzymes were compared in terms of their yields, using untreated sawdust (yellow pine wood) and carboxymethylcellulose (CMC) as substrates, at a standard pH and temperature. Also, the sawdust was pretreated with 1% alkaline hydrogen peroxide and the yield compared with the untreated sawdust hydrolysis to determine the importance of the substrate pretreatment.

  13. Immobilization of enzymes on alginic acid-polyacrylamide copolymers

    SciTech Connect

    Kumaraswamy, M.D.K.; Panduranga R.K.; Thomas J.K.; Santappa, M.

    1981-08-01

    In this report, the authors present initial results and limitations of a polymeric system for the immobilization of enzymes. Enzymes attached to insoluble polymers of natural and synthetic origin are gaining importance in many industrial and biomedical applications. Graft copolymers are used as enzyme supports and in this study a novel polymeric system of alginic acid-polyacrylamide graft copolymer is described which was used for immobilizing enzymes. (Refs. 4).

  14. Status of plutonium ceramic immobilization processes and immobilization forms

    SciTech Connect

    Ebbinghaus, B.B.; Van Konynenburg, R.A.; Vance, E.R.; Jostsons, A.

    1996-05-01

    Immobilization in a ceramic followed by permanent emplacement in a repository or borehole is one of the alternatives currently being considered by the Fissile Materials Disposition Program for the ultimate disposal of excess weapons-grade plutonium. To make Pu recovery more difficult, radioactive cesium may also be incorporated into the immobilization form. Valuable data are already available for ceramics form R&D efforts to immobilize high-level and mixed wastes. Ceramics have a high capacity for actinides, cesium, and some neutron absorbers. A unique characteristic of ceramics is the existence of mineral analogues found in nature that have demonstrated actinide immobilization over geologic time periods. The ceramic form currently being considered for plutonium disposition is a synthetic rock (SYNROC) material composed primarily of zirconolite (CaZrTi{sub 2}O{sub 7}), the desired actinide host phase, with lesser amounts of hollandite (BaAl{sub 2}Ti{sub 6}O{sub 16}) and rutile (TiO{sub 2}). Alternative actinide host phases are also being considered. These include pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}), zircon (ZrSiO{sub 4}), and monazite (CePO{sub 4}), to name a few of the most promising. R&D activities to address important technical issues are discussed. Primarily these include moderate scale hot press fabrications with plutonium, direct loading of PuO{sub 2} powder, cold press and sinter fabrication methods, and immobilization form formulation issues.

  15. Acid phosphatase and protease activities in immobilized rat skeletal muscles

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Troup, J. P.; Fitts, R. H.

    1982-01-01

    The effect of hind-limb immobilization on selected Iysosomal enzyme activities was studied in rat hing-limb muscles composed primarily of type 1. 2A, or 2B fibers. Following immobilization, acid protease and acid phosphatase both exhibited signifcant increases in their activity per unit weight in all three fiber types. Acid phosphatase activity increased at day 14 of immobilization in the three muscles and returned to control levels by day 21. Acid protease activity also changed biphasically, displaying a higher and earlier rise than acid phosphatase. The pattern of change in acid protease, but not acid phosphatase, closely parallels observed muscle wasting. The present data therefore demonstrate enhanced proteolytic capacity of all three fiber types early during muscular atrophy. In addition, the data suggest a dependence of basal hydrolytic and proteolytic activities and their adaptive response to immobilization on muscle fiber composition.

  16. Rational surface silane modification for immobilizing glucose oxidase.

    PubMed

    Tian, Feibao; Guo, Yi; Lin, Feifei; Zhang, Yumei; Yuan, Qipeng; Liang, Hao

    2016-06-01

    Glucose oxidase (GOx) has many significant applications in biosensor and biocatalysis. In this study, we firstly quantitatively analyzed the binding efficiency of (3-aminopropyl) trimethoxysilane (APTES) modified onto the surface of GOx. It was found that the contents of the grafted silane did not significantly influence the relative activities and tertiary structures of all surface modified GOxs. Immobilization ratio and relative activity of all instances of APTES modified GOx increased, compared with those of native enzyme. However, good stability of immobilized GOx at extreme pH and high temperature could only be obtained when modified protein with low binding silane content. At pH 2.0, the immobilized GOx with low binding content showed a more than 600% activity, compared to the free enzyme. Therefore, rational surface modification would be beneficial to improving the activity and stability of immobilized enzyme as well as increasing loading amount. PMID:26921503

  17. Effect of kinesthetic illusion induced by visual stimulation on muscular output function after short-term immobilization.

    PubMed

    Inada, Toru; Kaneko, Fuminari; Hayami, Tatsuya

    2016-04-01

    Kinesthetic illusions by visual stimulation (KiNVIS) enhances corticomotor excitability and activates motor association areas. The purpose of this study was to investigate the effect of KiNVIS induction on muscular output function after short-term immobilization. Thirty subjects were assigned to 3 groups: an immobilization group, with the left hand immobilized for 12h (immobilization period); an illusion group, with the left hand immobilized and additionally subjected to KiNVIS of the immobilized part during the immobilization period; and a control group with no manipulation. The maximum voluntary contraction (MVC), fluctuation of force (force fluctuation) during a force modulation task, and twitch force were measured both before (pre-test) and after (post-test) the immobilization period. Data were analyzed by performing two-way (TIME×GROUP) repeated measures ANOVA. The MVC decreased in the immobilization group only (pre-test; 37.8±6.1N, post-test; 32.8±6.9N, p<0.0005) after the immobilization period. The force fluctuation increased only in the immobilization group (pre-test; 2.19±0.54%, post-test; 2.78±0.87%, p=0.007) after the immobilization period. These results demonstrate that induction of KiNVIS prevents negative effect on MVC and force fluctuation after 12h of immobilization. PMID:26914845

  18. Effect of limb immobilization on skeletal muscle

    NASA Technical Reports Server (NTRS)

    Booth, F. W.

    1982-01-01

    Current knowledge and questions remaining concerning the effects of limb immobilization on skeletal muscle is reviewed. The most dramatic of these effects is muscle atrophy, which has been noted in cases of muscles fixed at or below their resting length. Immobilization is also accompanied by a substantial decrease in motoneuronal discharges, which results in the conversion of slow-twitch muscle to muscle with fast-twitch characteristics. Sarcolemma effects include no change or a decrease in resting membrane potential, the appearance of extrajunctional acetylcholine receptors, and no change in acetylcholinesterase activity. Evidence of changes in motoneuron after hyperpolarization characteristics suggests that the muscle inactivity is responsible for neuronal changes, rather than vice versa. The rate of protein loss from atrophying muscles is determined solely by the first-order rate constant for degradation. Various other biochemical and functional changes have been noted, including decreased insulin responsiveness and protein synthesis. The model of limb immobilization may also be useful for related studies of muscle adaptation.

  19. Immobilization of enzyme on a polymer surface

    NASA Astrophysics Data System (ADS)

    Shen, Lei; Cheng, Kenneth Chun Kuen; Schroeder, McKenna; Yang, Pei; Marsh, E. Neil G.; Lahann, Joerg; Chen, Zhan

    2016-06-01

    We successfully immobilized enzymes onto polymer surfaces via covalent bonds between cysteine groups of the enzyme and dibromomaleimide functionalities present at the polymer surface. In this work, we used nitroreductase (NfsB) as a model enzyme molecule. The polymers were prepared by chemical vapor deposition (CVD) polymerization, resulting in surfaces with dibromomaleimide groups. NfsB variants were engineered so that each NfsB molecule only has one cysteine group on the enzyme surface. Two different NfsB constructs were studied, with cysteines at the positions of H360 and V424, respectively. A combination of sum frequency generation (SFG) vibrational and attenuated total reflectance Fourier transformed infrared (ATR-FTIR) spectroscopies were used to deduce the orientation of the immobilized enzymes on the surface. It was found that the orientation of the immobilized enzymes is controlled by the position of the cysteine residue in the protein. The NfsB H360C construct exhibited a similar orientational behavior on the polymer surface as compared to that on the self-assembled monolayer surface, but the NsfB V424C construct showed markedly different orientations on the two surfaces.

  20. Methanogenesis from Sucrose by Defined Immobilized Consortia

    PubMed Central

    Jones, W. Jack; Guyot, Jean-Pierre; Wolfe, Ralph S.

    1984-01-01

    A bacterial consortium capable of sucrose degradation primarily to CH4 and CO2 was constructed, with acetate as the key methanogenic precursor. In addition, the effect of agar immobilization on the activity of the consortium was determined. The primary fermentative organism, Escherichia coli, produced acetate, formate, H2, and CO2 (known substrates for methanogens), as well as ethanol and lactate, compounds that are not substrates for methanogens. Oxidation of the nonmethanogenic substrates, lactate and ethanol, to acetate was mediated by the addition of Acetobacterium woodii and Desulfovibrio vulgaris. The methanogenic stage was accomplished by the addition of the acetophilic methanogen Methanosarcina barkeri and the hydrogenophilic methanogen Methanobacterium formicicum. Results of studies with low substrate concentrations (0.05 to 0.2% [wt/vol]), a growth-limiting medium, and the five-component consortium indicated efficient conversion (40%) of sucrose carbon to CH4. Significant decreases in yields of CH4 and rates of CH4 production were observed if any component of the consortium was omitted. Approximately 70% of the CH4 generated occurred via acetate. Agar-immobilized cells of the consortium exhibited yields of CH4 and rates of CH4 production from sucrose similar to those of nonimmobilized cells. The rate of CH4 production decreased by 25% when cysteine was omitted from reaction conditions and by 40% when the immobilized consortium was stored for 1 week at 4°C. PMID:16346452

  1. Methanogenesis from sucrose by defined immobilized consortia.

    PubMed

    Jones, W J; Guyot, J P; Wolfe, R S

    1984-01-01

    A bacterial consortium capable of sucrose degradation primarily to CH(4) and CO(2) was constructed, with acetate as the key methanogenic precursor. In addition, the effect of agar immobilization on the activity of the consortium was determined. The primary fermentative organism, Escherichia coli, produced acetate, formate, H(2), and CO(2) (known substrates for methanogens), as well as ethanol and lactate, compounds that are not substrates for methanogens. Oxidation of the nonmethanogenic substrates, lactate and ethanol, to acetate was mediated by the addition of Acetobacterium woodii and Desulfovibrio vulgaris. The methanogenic stage was accomplished by the addition of the acetophilic methanogen Methanosarcina barkeri and the hydrogenophilic methanogen Methanobacterium formicicum. Results of studies with low substrate concentrations (0.05 to 0.2% [wt/vol]), a growth-limiting medium, and the five-component consortium indicated efficient conversion (40%) of sucrose carbon to CH(4). Significant decreases in yields of CH(4) and rates of CH(4) production were observed if any component of the consortium was omitted. Approximately 70% of the CH(4) generated occurred via acetate. Agar-immobilized cells of the consortium exhibited yields of CH(4) and rates of CH(4) production from sucrose similar to those of nonimmobilized cells. The rate of CH(4) production decreased by 25% when cysteine was omitted from reaction conditions and by 40% when the immobilized consortium was stored for 1 week at 4 degrees C. PMID:16346452

  2. Preparation and properties of immobilized amyloglucosidase

    SciTech Connect

    Nithianandam, V.S.; Srinivasan, K.S.V.; Thomas Joseph, K.; Santappa, M.

    1981-10-01

    Amyloglucosidase was immobilized on a copolymer of methyl methacrylate and 2-di-methylaminoethyl methacrylate. The resulting immobilized amyloglucosidase has 19% of the soluble enzyme specific activity. The pH optimum of immobilized amyloglucosidase is shifted towards acidity by 1.9 units. The temperature optimum of immobilized enzyme is shifted upward by 5 degrees C. The immobilized amyloglucosidase has the maximum stability at pH 4.6, whereas the soluble enzyme has maximum stability at pH 5.5. While soluble amyloglucosidase has a maximum thermal stability at 50 degrees C, the stability of the immobilized amyloglucosidase steadily decreases with the increase in temperature. (Refs. 7).

  3. Depression of osteoblastic activity in immobilized limbs of suckling rats.

    PubMed

    Weinreb, M; Rodan, G A; Thompson, D D

    1991-07-01

    Recently we characterized the immobilization-related osteopenia in adult rats and showed that it is caused by increased bone resorption and decreased bone formation (Weinreb et al. 1989 Bone 10:187). To assess the effect of age on disuse osteopenia, this study investigated the effects of immobilization on bone turnover in very young, suckling rats. The 15-day-old rats underwent unilateral hind limb immobilization by sciatic neurectomy; the contralateral limb was left intact and served as control. Experimental or sham-operated animals were killed after 0, 2, 4, or 12 days postsurgery. Dry, fat-free weight and ash weight were determined in both femora, and both tibiae were subjected to static and dynamic histomorphometry. Immobilization caused a progressive deficit in bone mass in the immobilized limb compared to the contralateral intact limb but did not affect femoral longitudinal growth. The total mineral content in the immobilized femora was 13.6% less than that in the intact limb by day 12. Concomitantly, tibial cancellous bone area and perimeter declined in the immobilized limb by 37.3 and 32.2%, respectively. This reduction in bone mass in the tibiae of immobilized limbs was associated with increased bone resorption, expressed as osteoclast perimeter, number of osteoclasts per mm surface, and number of osteoclasts per mm2 tissue area. Bone formation was reduced as a result of impaired osteoblast activity as evidenced by (1) decreased endocortical and trabecular mineral apposition rate; (2) reduced trabecular mineral formation rate; (3) decreased percentage of ash of the femoral dry weight; and (4) increased volume of unmineralized osteoid in the tibial metaphysis.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1950676

  4. New immobilized cell system with protection against toxic solvents

    SciTech Connect

    Tanaka, H.; Harada, S.; Kurosawa, H.; Yajima, M.

    1987-01-01

    A new immobilized cell system providing protection against toxic solvents was investigated so that normal fermentations could be carried out in a medium containing toxic solvents. The system consists of immobilized growing cells in Ca-alginate gel beads to which vegetable oils, which are inexpensive absorbents of solvents, had been added. The ethanol fermentation of Saccharomyces cerevisiae ATCC 26603 was used as a model fermentation to study the protection afforded by the system against solvent toxicities. The fermentation was inhibited by solvents such as 2-octanol, benzene, toluene, and phenol. Ethanol production of one batch was not finished even after 35 h using immobilized growing yeast cells in conventional Ca-alginate gel beads in an ethanol production medium (5% glucose) containing 0.1% 2-octanol, which is used as a solvent for liquid-liquid extraction and is one of the most toxic solvents in our experiments. With the new immobilized growing cell system using vegetable oils, however, four repeated batch fermentations were completed in 35 h. Castor oil provided even more protection than soy bean, olive, and tung oils, and it was possible to complete six repeated batches in 35 h. The immobilized cell system with vegetable oils also provided protection against other toxic solvents such as benzene and toluene. A possible mechanism for the protective function of the new immobilized cell system is discussed.

  5. Aminohydroxybutane bisphosphonate inhibits bone loss due to immobilization in rats.

    PubMed

    Thompson, D D; Seedor, J G; Weinreb, M; Rosini, S; Rodan, G A

    1990-03-01

    The purpose of this study was to document the effects of aminobutane bisphosphonate (AHBuP) on bone remodeling during immobilization in rats. Male Sprague-Dawley rats underwent unilateral sciatic neurectomy after receiving two daily subcutaneous injections of 0, 0.01, 0.10, or 1.0 mg P per kg AHBuP. Rats were sacrificed at 24 h or 10 or 20 days postimmobilization. Femora were ashed and tibiae were prepared for histomorphometric analysis. AHBuP was effective in inhibiting bone loss due to immobilization in a dose-dependent manner. The percentage loss of femoral ash weight due to immobilization decreased in a dose-dependent manner. In vehicle-treated rats, there was a significant decrease in trabecular bone volume (TBV) in the immobilized tibiae compared to the normal tibiae; in AHBuP-treated rats there was a dose-dependent increase in TBV both in the immobilized and control tibiae. The osteoid surface extent was decreased in AHBuP-treated rats in a dose-dependent manner. The mineral apposition rate was altered only in the intact leg of rats treated with 0.1 and 1.0 mg P AHBuP per kg compared to vehicle treated. Osteoclast number per mm was reduced by AHBuP treatment. In conclusion, aminohydroxybutane bisphosphonate effectively prevented the bone loss due to immobilization in this system. PMID:2333787

  6. Immobilization of pectin depolymerising polygalacturonase using different polymers.

    PubMed

    Ur Rehman, Haneef; Aman, Afsheen; Nawaz, Muhammad Asif; Karim, Asad; Ghani, Maria; Baloch, Abdul Hameed; Ul Qader, Shah Ali

    2016-01-01

    Polygalacturonase catalyses the hydrolysis of pectin substances and widely has been used in food and textile industries. In current study, different polymers such as calcium alginate beads, polyacrylamide gel and agar-agar matrix were screened for the immobilization of polygalacturonase through entrapment technique. Polyacrylamide gel was found to be most promising one and gave maximum (89%) immobilization yield as compared to agar-agar (80%) and calcium alginate beads (46%). The polymers increased the reaction time of polygalacturonase and polymers entrapped polygalacturonases showed maximum pectinolytic activity after 10 min of reaction as compared to free polygalacturonase which performed maximum activity after 5.0 min of reaction time. The temperature of polygalacturonase for maximum enzymatic activity was increased from 45°C to 50°C and 55°C when it was immobilized within agar-agar and calcium alginate beads, respectively. The optimum pH (pH 10) of polygalacturonase was remained same when it was immobilized within polyacrylamide gel and calcium alginate beads, but changed from pH 10 to pH 9.0 after entrapment within agar-agar. Thermal stability of polygalacturonase was improved after immobilization and immobilized polygalacturonases showed higher tolerance against different temperatures as compared to free enzyme. Polymers entrapped polygalacturonases showed good reusability and retained more than 80% of their initial activity during 2nd cycles. PMID:26454112

  7. Nucleosome immobilization strategies for single-pair FRET microscopy.

    PubMed

    Koopmans, Wiepke J A; Schmidt, Thomas; van Noort, John

    2008-10-01

    All genomic transactions in eukaryotes take place in the context of the nucleosome, the basic unit of chromatin, which is responsible for DNA compaction. Overcoming the steric hindrance that nucleosomes present for DNA-processing enzymes requires significant conformational changes. The dynamics of these have been hard to resolve. Single-pair Fluorescence Resonance Energy Transfer (spFRET) microscopy is a powerful technique for observing conformational dynamics of the nucleosome. Nucleosome immobilization allows the extension of observation times to a limit set only by photobleaching, and thus opens the possibility of studying processes occurring on timescales ranging from milliseconds to minutes. It is crucial however, that immobilization itself does not introduce artifacts in the dynamics. Here we report on various nucleosome immobilization strategies, such as single-point attachment to polyethylene glycol (PEG) or surfaces coated with bovine serum albumin (BSA), and confinement in porous agarose or polyacrylamide gels. We compare the immobilization specificity and structural integrity of immobilized nucleosomes. A crosslinked star polyethylene glycol coating performs best with respect to tethering specificity and nucleosome integrity, and enables us to reproduce for the first time bulk nucleosome unwrapping kinetics in single nucleosomes without immobilization artifacts. PMID:18792054

  8. [Growth inhibition effect of immobilized pectinase on Microcystis aeruginosa].

    PubMed

    Shen, Qing-Qing; Peng, Qian; Lai, Yong-Hong; Ji, Kai-Yan; Han, Xiu-Lin

    2012-12-01

    To confirm the growth inhibition effect of immobilized pectinase on algae, co-cultivation method was used to investigate the effect of immobilized pectinase on the growth of Microcystis aeruginosa. After co-cultivation, the damage status of the algae was observed through electron microscope, and the effect of immobilized pectase on the physiological and biochemical characteristics of the algae was also measured. The results showed that the algae and immobilized pectase co-cultivated solution etiolated distinctly on the third day and there was a significantly positive correlation between the extent of etiolation and the dosage as well as the treating time of the immobilized pectinase. Under electron microscope, plasmolysis was found in the slightly damaged cells, and the cell surface of these cells was rough, uneven and irregular; the severely damaged cells were collapsed or disintegrated completely. The algal yield and the chlorophyll a content decreased significantly with the increase of the treating time. The measurement of the malondiadehyde (MDA) value showed that the antioxidation system of the treated algal cells was destroyed, and their membrane lipid was severely peroxidated. The study indicated that the immobilized pectinase could efficiently inhibit the growth of M. aeruginosa, and the inhibitory rate reached up to 96%. PMID:23379158

  9. Nanoporous gold for enzyme immobilization.

    PubMed

    Stine, Keith J; Jefferson, Kenise; Shulga, Olga V

    2011-01-01

    Nanoporous gold (NPG) is a material of emerging interest for immobilization of biomolecules and -especially enzymes. NPG materials provide a high gold surface area onto which biomolecules can either be directly physisorbed or covalently linked after first modifying the NPG with a self-assembled monolayer. The material can be used as a high surface area electrode and with immobilized enzymes can be used for amperometric detection schemes. NPG can be prepared in a variety of formats from alloys containing less than 50 atomic% gold by dealloying procedures. Related high surface area gold structures have been prepared using templating approaches. Covalent enzyme immobilization can be achieved by first forming a self-assembled monolayer on NPG bearing a terminal reactive functional group followed by conjugation to the enzyme through amide linkages to lysine residues. PMID:20865389

  10. Detrimental effects of immobilization on functional recovery after sciatic nerve crush.

    PubMed

    Sarikcioglu, Levent; Ozkan, Olcay; Gurer, Elif Inanc

    2005-07-01

    Peripheral-nerve trauma has been a challenge to surgeons, with significant advances in the surgery of repair. Immobilization of the injured limb after repair has been the traditional method of treatment. Although peripheral-nerve regeneration has been studied extensively, the correlation between functional recovery and the immobilization period has not been well-documented. In the present study, the authors studied the effects of immobilization on axonal regeneration after sciatic crush injury. They found a detrimental effect of immobilization on the functional recovery. PMID:15971165

  11. Short-term immobilization influences use-dependent cortical plasticity and fine motor performance.

    PubMed

    Opie, George M; Evans, Alexandra; Ridding, Michael C; Semmler, John G

    2016-08-25

    Short-term immobilization that reduces muscle use for 8-10h is known to influence cortical excitability and motor performance. However, the mechanisms through which this is achieved, and whether these changes can be used to modify cortical plasticity and motor skill learning, are not known. The purpose of this study was to investigate the influence of short-term immobilization on use-dependent cortical plasticity, motor learning and retention. Twenty-one adults were divided into control and immobilized groups, both of which underwent two experimental sessions on consecutive days. Within each session, transcranial magnetic stimulation (TMS) was used to assess motor-evoked potential (MEP) amplitudes, short- (SICI) and long-interval intracortical inhibition (LICI), and intracortical facilitation (ICF) before and after a grooved pegboard task. Prior to the second training session, the immobilized group underwent 8h of left hand immobilization targeting the index finger, while control subjects were allowed normal limb use. Immobilization produced a reduction in MEP amplitudes, but no change in SICI, LICI or ICF. While motor performance improved for both groups in each session, the level of performance was greater 24-h later in control, but not immobilized subjects. Furthermore, training-related MEP facilitation was greater after, compared with before, immobilization. These results indicate that immobilization can modulate use-dependent plasticity and the retention of motor skills. They also suggest that changes in intracortical excitability are unlikely to contribute to the immobilization-induced modification of cortical excitability. PMID:27282084

  12. Characterization of immobilized enzymes in polyurethane foams in a dynamic bed reactor.

    PubMed

    Hu, Z C; Korus, R A; Stormo, K E

    1993-06-01

    beta-D-Galactosidase (E 3.2.1.23) from Aspergillus oryzae was immobilized with polyurethane foam (PUF). Among several immobilization methods attempted in this work, the immobilized enzyme preparation by in-situ co-polymerization between enzyme and prepolymer HYPOL 3000 showed the highest activity. The intrinsic kinetics of PUF-immobilized enzyme was determined in a dynamic bed reactor, used to increase transport rates. The immobilization mechanism in PUF was studied by measurements of immobilized enzyme kinetics and by using scanning electron microscopy combined with immuno-gold labeling techniques. The results showed that immobilization was predominantly by covalent bonding between primary amino groups of beta-D-galactosidase and isocyanate groups of the prepolymers. Entrapment in the PUF micropores assisted the immobilization of enzymes, and adsorption on the surface of macropores was not important for immobilization. The bicinchoninic acid method was applied for the determination of PUF loading capacity and specific enzyme activity and used to determine enzyme deactivation during immobilization. PMID:7763711

  13. Immobilization of Mucor miehei Lipase onto Macroporous Aminated Polyethersulfone Membrane for Enzymatic Reactions

    PubMed Central

    Handayani, Nurrahmi; Loos, Katja; Wahyuningrum, Deana; Buchari; Zulfikar, Muhammad Ali

    2012-01-01

    Immobilization of enzymes is one of the most promising methods in enzyme performance enhancement, including stability, recovery, and reusability. However, investigation of suitable solid support in enzyme immobilization is still a scientific challenge. Polyethersulfone (PES) and aminated PES (PES–NH2) were successfully synthesized as novel materials for immobilization. Membranes with various pore sizes (from 10–600 nm) based on synthesized PES and PES–NH2 polymers were successfully fabricated to be applied as bioreactors to increase the immobilized lipase performances. The influence of pore sizes, concentration of additives, and the functional groups that are attached on the PES backbone on enzyme loading and enzyme activity was studied. The largest enzyme loading was obtained by Mucor miehei lipase immobilized onto a PES–NH2 membrane composed of 10% of PES–NH2, 8% of dibutyl phthalate (DBP), and 5% of polyethylene glycol (PEG) (872.62 µg/cm2). Hydrolytic activity of the immobilized lipases indicated that the activities of biocatalysts are not significantly decreased by immobilization. From the reusability test, the lipase immobilized onto PES–NH2 showed a better constancy than the lipase immobilized onto PES (the percent recovery of the activity of the lipases immobilized onto PES–NH2 and PES are 97.16% and 95.37%, respectively), which indicates that this novel material has the potential to be developed as a bioreactor for enzymatic reactions. PMID:24958172

  14. Biodiesel production from Jatropha oil catalyzed by immobilized Burkholderia cepacia lipase on modified attapulgite.

    PubMed

    You, Qinghong; Yin, Xiulian; Zhao, Yuping; Zhang, Yan

    2013-11-01

    Lipase from Burkholderia cepacia was immobilized on modified attapulgite by cross-linking reaction for biodiesel production with jatropha oil as feedstock. Effects of various factors on biodiesel production were studied by single-factor experiment. Results indicated that the best conditions for biodiesel preparation were: 10 g jatropha oil, 2.4 g methanol (molar ratio of oil to methanol is 1:6.6) being added at 3h intervals, 7 wt% water, 10 wt% immobilized lipase, temperature 35°C, and time 24h. Under these conditions, the maximum biodiesel yield reached 94%. The immobilized lipase retained 95% of its relative activity during the ten repeated batch reactions. The half-life time of the immobilized lipase is 731 h. Kinetics was studied and the Vmax of the immobilized lipases were 6.823 mmol L(-1). This immobilized lipase catalyzed process has potential industrial use for biodiesel production to replace chemical-catalyzed method. PMID:24055964

  15. Bioreduction and immobilization of uranium in situ: a case study at a USA Department of Energy radioactive waste site, Oak Ridge, Tennessee

    SciTech Connect

    Wu, Weimin; Carley, Jack M; Watson, David B; Gu, Baohua; Brooks, Scott C; Kelly, Shelly D; Kemner, Kenneth M; Van Nostrand, Joy; Wu, Liyou; Zhou, Jizhong; Luo, Jian; Cardenas, Erick; Fields, Matthew Wayne; Marsh, Terence; Tiedje, James; Green, Stefan; Kostka, Joel; Kitanidis, Peter K.; Jardine, Philip; Criddle, Craig

    2011-01-01

    Bioremediation of uranium contaminated groundwater was tested by delivery of ethanol as an electron donor source to stimulate indigenous microbial bioactivity for reduction and immobilization of uranium in situ, followed by tests of stability of uranium sequestration in the bioreduced area via delivery of dissolved oxygen or nitrate at the US Department of energy's Integrated Field Research Challenge site located at Oak Ridge, Tennessee, USA. After long term treatment that spanned years, uranium in groundwater was reduced from 40-60 mg {center_dot} L{sup -1} to <0.03 mg {center_dot} L{sup -1}, below the USA EPA standard for drinking water. The bioreduced uranium was stable under anaerobic or anoxic conditions, but addition of DO and nitrate to the bioreduced zone caused U remobilization. The change in the microbial community and functional microorganisms related to uranium reduction and oxidation were characterized. The delivery of ethanol as electron donor stimulated the activities of indigenous microorganisms for reduction of U(VI) to U(IV). Results indicated that the immobilized U could be partially remobilized by D0 and nitrate via microbial activity. An anoxic environmental condition without nitrate is essential to maintain the stability of bioreduced uranium.

  16. Study of phenol biodegradation using Bacillus amyloliquefaciens strain WJDB-1 immobilized in alginate-chitosan-alginate (ACA) microcapsules by electrochemical method.

    PubMed

    Lu, Daban; Zhang, Yan; Niu, Shiquan; Wang, Letao; Lin, Shaoxiong; Wang, Chunming; Ye, Weichun; Yan, Chunlei

    2012-04-01

    An aerobic microorganism with an ability to utilize phenol as sole carbon and energy source was isolated from phenol-contaminated wastewater samples. The isolate was identified as Bacillus amyloliquefaciens strain WJDB-1 based on morphological, physiological, and biochemical characteristics, and 16S rDNA sequence analysis. Strain WJDB-1 immobilized in alginate-chitosan-alginate (ACA) microcapsules could degrade 200 mg/l phenol completely within 36 h. The concentration of phenol was determined using differential pulse voltammetry (DPV) at glassy carbon electrode (GCE) with a linear relationship between peak current and phenol concentration ranging from 2.0 to 20.0 mg/l. Cells immobilized in ACA microcapsules were found to be superior to the free suspended ones in terms of improving the tolerance to the environmental loadings. The optimal conditions to prepare microcapsules for achieving higher phenol degradation rate were investigated by changing the concentrations of sodium alginate, calcium chloride, and chitosan. Furthermore, the efficiency of phenol degradation was optimized by adjusting various processing parameters, such as the number of microcapsules, pH value, temperature, and the initial concentration of phenol. This microorganism has the potential for the efficient treatment of organic pollutants in wastewater. PMID:21809019

  17. Immobilization of penicillin acylase on copolymer of butyl acrylate and ethylene glycol dimethacrylate.

    PubMed

    Bryjak, J; Noworyta, A

    1993-01-01

    The effects of glutaraldehyde, enzyme concentrations and reactants volumes, ionic strength, pH value and carrier particle diameter on immobilization of penicillin acylase onto acrylic carriers were studied. The activity of immobilized enzyme preparations was also studied over a range of pH values and temperatures and thermal and pH stabilities were determined. The use of the immobilized preparation for penicillin G hydrolysis in a batch reactor was investigated. The immobilized enzyme gave a significant reduction in hydrolysis time compared to hydrolysis by the native enzyme. PMID:7763686

  18. [X-ray microanalysis of the activity of immobilized urease on chitosan membrane].

    PubMed

    Ma, Xiao-li; Yao, Zi-hua

    2005-03-01

    The localization of the activity of immobilized urease on chitosan membrane was studied by X-ray microanalysis. BaCl2 and urea were selected as the capture and substrate respectively. The substrate was hydrolyzed by immobilized urease to produce NH3 and CO2 in Tris-HCl buffer (pH 7.0), and the latter was captured by BaCl2 to form precipitate. The precipite was deposited on the active site of immobilized urease. It is shown that the method is practicable and reliable. The optimum condition for the localization of activity of immobilized urease was studied. PMID:16013332

  19. Graphene oxide immobilized enzymes show high thermal and solvent stability

    NASA Astrophysics Data System (ADS)

    Hermanová, Soňa; Zarevúcká, Marie; Bouša, Daniel; Pumera, Martin; Sofer, Zdeněk

    2015-03-01

    The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed lipase achieved over 100% of the initial activity in a series of organic solvents. These findings, showing enhanced thermal stability and solvent tolerance of graphene oxide immobilized enzyme, will have a profound impact on practical industrial scale uses of enzymes for the conversion of lipids into fuels.The thermal and solvent tolerance of enzymes is highly important for their industrial use. We show here that the enzyme lipase from Rhizopus oryzae exhibits exceptionally high thermal stability and high solvent tolerance and even increased activity in acetone when immobilized onto a graphene oxide (GO) nanosupport prepared by Staudenmaier and Brodie methods. We studied various forms of immobilization of the enzyme: by physical adsorption, covalent attachment, and additional crosslinking. The activity recovery was shown to be dependent on the support type, enzyme loading and immobilization procedure. Covalently immobilized lipase showed significantly better resistance to heat inactivation (the activity recovery was 65% at 70 °C) in comparison with the soluble counterpart (the activity recovery was 65% at 40 °C). Physically adsorbed

  20. Nonspecific collagenolytic activity of the femoral bone in immobilized rat extremities.

    PubMed

    Prokopová, D; Tesárek, B; Susta, A

    1975-01-01

    Nonspecific collagenolytic activity was studied in rat bones after immobilization. The left hind limb was immobilized by sectioning the sciatic nerve. Enzyme activity was determined by using synthetic pentapeptide substrate (Pz-Pro-Leu-Gly-Pro-D-Arg). After immobilization the activity of nonspecific collagenase increased and reached its maximum on the third day after the operation. The activity was decreased after one week and attained levels of control bones three weeks after sciatic nerve section. PMID:167392

  1. Effects of immobilization on articular cartilage: Autohistoradiographic findings with S35

    NASA Technical Reports Server (NTRS)

    Digiovanni, C.; Desantis, E.

    1980-01-01

    The effect of immobilization on the articular cartilage of rabbits was studied by light microscope. The knee joint of each rabbit was immobilized in a plaster in a position midway between flexion and extension for a 10 to 120 days period. Degenerative changes in the articular cartilage of increasing severity were observed. The fixation of the labeled SO4 by cartilage cells was decreased in advanced immobilization.

  2. Role of immobilization of irradiated rats in the protective effect of bone marrow shielding

    NASA Technical Reports Server (NTRS)

    Gronskaya, N. F.; Strelin, G. S.

    1982-01-01

    Rats were exposed to X-radiation to study the influence of immobilization and shielding of part of bone marrow during exposure on survival. It is concluded that (1) the beneficial effect of the stress factor (created by the immobilization of rats during exposure) can aggregate with the effect of bone marrow shielding and, under certain conditions, imitate the latter; and (2) the probability of the protective effect of immobilization should be taken into account when assessing the influence of bone marrow shielding.

  3. Preparation, characterization, and luminescence of (SBA-15) immobilized pepsin

    NASA Astrophysics Data System (ADS)

    Zhai, Qing-Zhou; Sun, Si-Jia

    2014-12-01

    SBA-15 mesoporous silica was synthesized by hydrothermal method and its surface was methylated by treatment with methyltrimethoxysilane. Pepsin was immobilized on the obtained materials giving host-guest composite materials (SBA-15)-pepsin and (methylated SBA-15)-pepsin. The optimum conditions for preparation of these materials were established. Methylated SBA-15 (M-SBA-15) has improved immobilization efficiency of enzyme compared to initial SBA-15 silica. It was shown that with the gradual increase of NaCl solution ionic strength the immobilized amount of enzyme was reduced. Powder X-ray diffraction and Fourier transform infrared spectroscopy showed that the host frameworks in the prepared host-guest composite materials are intact and the ordered structure was retained. Scanning electron microscopic studies revealed fibrous morphologic characteristics of the SBA-15 and the immobilized pepsin composite materials. The average particle diameter of (SBA-15)-pepsin composite was 338 ± 10 and 343 ± 10 nm for (M-SBA-15)-pepsin. The low temperature N2 adsorption-desorption study at 77 K showed that the pore sizes and specific surface areas of the host-guest composite materials were smaller than those before the introduction of the enzyme, suggesting that the immobilized enzyme occupied a definite position in the host material pore channels. The UV-vis solid diffuse reflectance and luminescence studies showed that the enzyme was successfully immobilized on to the host material and that after the immobilization of enzyme on SBA-15 the conformation of pepsin macromolecule has not been changed.

  4. Enzyme immobilization and biocatalysis of polysiloxanes

    NASA Astrophysics Data System (ADS)

    Poojari, Yadagiri

    Lipases have been proven to be versatile and efficient biocatalysts which can be used in a broad variety of esterification, transesterification, and ester hydrolysis reactions. Due to the high chemo-, regio-, and stereo-selectivity and the mild conditions of lipase-catalyzed reactions, the vast potential of these biocatalysts for use in industrial applications has been increasingly recognized. Polysiloxanes (silicones) are well known for their unique physico-chemical properties and can be prepared in the form of fluids, elastomers, gels and resins for a wide variety of applications. However, the enzymatic synthesis of silicone polyesters and copolymers is largely unexplored. In the present investigations, an immobilized Candida antarctica lipase B (CALB) on macroporous acrylic resin beads (Novozym-435 RTM) has been successfully employed as a catalyst to synthesize silicone polyesters and copolymers under mild reaction conditions. The silicone aliphatic polyesters and the poly(dimethylsiloxane)--poly(ethylene glycol) (PDMS-PEG) copolymers were synthesized in the bulk (without using a solvent), while the silicone aromatic polyesters, the silicone aromatic polyamides and the poly(epsilon-caprolactone)--poly(dimethylsiloxane)--poly(epsilon-caprolactone) (PCL-PDMS-PCL) triblock copolymers were synthesized in toluene. The synthesized silicone polyesters and copolymers were characterized by Gel Permeation Chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD). This dissertation also describes a methodology for physical immobilization of the enzyme pepsin from Porcine stomach mucosa in silicone elastomers utilizing condensation-cure room temperature vulcanization (RTV) of silanol-terminated poly(dimethylsiloxane) (PDMS). The activity and the stability of free pepsin and pepsin immobilized in silicone elastomers were studied with respect to p

  5. Mineral induction by immobilized phosphoproteins

    NASA Technical Reports Server (NTRS)

    Saito, T.; Arsenault, A. L.; Yamauchi, M.; Kuboki, Y.; Crenshaw, M. A.

    1997-01-01

    Dentin phosphoproteins are thought to have a primary role in the deposition of mineral on the collagen of dentin. In this study we determined the type of binding between collagen and phosphoproteins necessary for mineral formation onto collagen fibrils and whether the phosphate esters are required. Bovine dentin phosphophoryn or phosvitin from egg yolk were immobilized on reconstituted skin type I collagen fibrils by adsorption or by covalent cross-linking. In some samples the ester phosphate was removed from the covalently cross-linked phosphoproteins by treatment with acid phosphatase. All samples were incubated at 37 degrees C in metastable solutions that do not spontaneously precipitate. Reconstituted collagen fibrils alone did not induce mineral formation. The phosphoproteins adsorbed to the collagen fibrils desorbed when the mineralization medium was added, and mineral was not induced. The mineral induced by the cross-linked phosphoproteins was apatite, and the crystals were confined to the surface of the collagen fibrils. With decreasing medium saturation the time required for mineral induction increased. The interfacial tensions calculated for apatite formation by either phosphoprotein cross-linked to collagen were about the same as that for phosphatidic acid liposomes and hydroxyapatite. This similarity in values indicates that the nucleation potential of these highly phosphorylated surfaces is about the same. It is concluded that phosphoproteins must be irreversibly bound to collagen fibrils for the mineralization of the collagen network in solutions that do not spontaneously precipitate. The phosphate esters of phosphoproteins are required for mineral induction, and the carboxylate groups are not sufficient.

  6. Metal immobilization and soil amendment efficiency at a contaminated sediment landfill site: a field study focusing on plants, springtails, and bacteria.

    PubMed

    Bert, Valérie; Lors, Christine; Ponge, Jean-François; Caron, Lucie; Biaz, Asmaa; Dazy, Marc; Masfaraud, Jean-François

    2012-10-01

    Metal immobilization may contribute to the environmental management strategy of dredged sediment landfill sites contaminated by metals. In a field experiment, amendment effects and efficiency were investigated, focusing on plants, springtails and bacteria colonisation, metal extractability and sediment ecotoxicity. Conversely to hydroxylapatite (HA, 3% DW), the addition of Thomas Basic Slag (TBS, 5% DW) to a 5-yr deposited sediment contaminated with Zn, Cd, Cu, Pb and As resulted in a decrease in the 0.01 M Ca(NO(3))(2)-extractable concentrations of Cd and Zn. Shoot Cd and Zn concentration in Calamagrostis epigejos, the dominant plant species, also decreased in the presence of TBS. The addition of TBS and HA reduced sediment ecotoxicity and improved the growth of the total bacterial population. Hydroxylapatite improved plant species richness and diversity and decreased antioxidant enzymes in C. Epigejos and Urtica dïoica. Collembolan communities did not differ in abundance and diversity between the different treatments. PMID:22647548

  7. Degradation of mix hydrocarbons by immobilized cells of mix culture using a trickle fluidized bed reactor

    SciTech Connect

    Chapatwala, K.D.

    1993-01-01

    The microorganisms, capable of degrading mix hydrocarbons were isolated from the soil samples collected from the hydrocarbon contaminated sites. The mix cultures were immobilized in calcium alginate solution in the form of beads. A trickle fluidized bed air-uplift-type reactor designed to study the degradation of mix hydrocarbons was filled with 0.85% normal saline containing the immobilized cells of mix culture. The immobilized beads were aerated with CO[sub 2]-free air at 200 ml/min. The degradation of different concentrations of hydrocarbons in the presence/absence of commercially available fertilizers by the immobilized cells of mix culture is now in progress.

  8. Growth and by-product profiles of Kluyveromyces marxianus cells immobilized in foamed alginate.

    PubMed

    Wilkowska, Agnieszka; Kregiel, Dorota; Guneser, Onur; Karagul Yuceer, Yonca

    2015-01-01

    The aim of this research was to study how the yeast cell immobilization technique influences the growth and fermentation profiles of Kluyveromyces marxianus cultivated on apple/chokeberry and apple/cranberry pomaces. Encapsulation of the cells was performed by droplet formation from a foamed alginate solution. The growth and metabolic profiles were evaluated for both free and immobilized cells. Culture media with fruit waste produced good growth of free as well as immobilized yeast cells. The fermentation profiles of K. marxianus were different with each waste material. The most varied aroma profiles were noted for immobilized yeast cultivated on apple/chokeberry pomace. PMID:25277269

  9. Evaluation of an organo-layered double hydroxide and two organic residues as amendments to immobilize metalaxyl enantiomers in soils: A comparative study.

    PubMed

    López-Cabeza, Rocío; Cornejo, Juan; Celis, Rafael

    2016-10-01

    Many pollutants released into the environment as a result of human activities are chiral. Pollution control strategies generally consider chiral compounds as if they were achiral and rarely consider enantiomers separately. We compared the performance of three different materials, an organically-modified anionic clay (HT-ELA) and two organic agro-food residues (ALP and ALPc), as amendments to immobilize the chiral fungicide metalaxyl in two soils with different textures, addressing the effects of the amendments on the sorption, persistence, and leaching of each of the two enantiomers of metalaxyl (R-metalaxyl and S-metalaxyl) separately. The effects of the amendments were both soil- and amendment-dependent, as well as enantiomer-selective. The organo-clay (HT-ELA) was much more efficient in increasing the sorption capacity of the soils for the two enantiomers of metalaxyl than the agro-food residues (ALP and ALPc), even when applied at a reduced application rate. The enhanced sorption in HT-ELA-amended soils reduced the bioavailability of metalaxyl enantiomers and their leaching in the soils, mitigating the particularly high leaching potential of the more persistent S enantiomer. The immobilizing capacity of the agro-food residues was more variable, mainly because their addition did not greatly ameliorate the sorption capacity of the soils and had variable effects on the enantiomers degradation rates. HT-ELA showed potential to reduce the bioavailability and mobility of metalaxyl enantiomers in soil and to mitigate the contamination problems particularly associated with the higher leaching potential of the more persistent enantiomer. PMID:27341374

  10. Immobilization of Heparin: Approaches and Applications

    PubMed Central

    Murugesan, Saravanababu; Xie, Jin; Linhardt, Robert J.

    2014-01-01

    Heparin, an anticoagulant, has been used in many forms to treat various diseases. These forms include soluble heparin and heparin immobilized to supporting matrices by physical adsorption, by covalent chemical methods and by photochemical attachment. These immobilization methods often require the use of spacers or linkers. This review examines and compares various techniques that have been used for the immobilization of heparin as well as applications of these immobilized heparins. In the applications reviewed, immobilized heparin is compared with soluble heparin for efficient and versatile use in each of the various applications. PMID:18289079

  11. Recent developments and applications of immobilized laccase.

    PubMed

    Fernández-Fernández, María; Sanromán, M Ángeles; Moldes, Diego

    2013-12-01

    Laccase is a promising biocatalyst with many possible applications, including bioremediation, chemical synthesis, biobleaching of paper pulp, biosensing, textile finishing and wine stabilization. The immobilization of enzymes offers several improvements for enzyme applications because the storage and operational stabilities are frequently enhanced. Moreover, the reusability of immobilized enzymes represents a great advantage compared with free enzymes. In this work, we discuss the different methodologies of enzyme immobilization that have been reported for laccases, such as adsorption, entrapment, encapsulation, covalent binding and self-immobilization. The applications of laccase immobilized by the aforementioned methodologies are presented, paying special attention to recent approaches regarding environmental applications and electrobiochemistry. PMID:22398306

  12. Effects of acoustic wave resonance oscillation on immobilized enzyme

    NASA Astrophysics Data System (ADS)

    Nishiyama, Hiroshi; Watanabe, Tomoya; Inoue, Yasunobu

    2014-03-01

    In aiming at developing a new method to artificially activate enzyme catalysts immobilized on surface, the effects of resonance oscillation of bulk acoustic waves were studied. Glucose oxidase (GOD) was immobilized by a covalent coupling method on a ferroelectric lead zirconate titanate (PZT) device that was able to generate thickness-extensional resonance oscillation (TERO). Glucose oxidation by the GOD enzyme was studied in a microreactor. The generation of TERO immediately increased the catalytic activity of immobilized GOD by a factor of 2-3. With turn-off of TERO, no significant activity decrease occurred, and 80-90% of the enhanced activity was maintained while the reaction proceeded. The almost complete reversion of the activity to the original low level before TERO generation was observed when the immobilized GOD was exposed to a glucose substrate-free solution. These results indicated that the presence of glucose substrate was essential for TERO-induced GOD activation and preservation of the increased activity level. The influences of reaction temperature, glucose concentration, pH, and rf electric power on the TERO activation showed that TERO strengthened the interactions of the immobilized enzyme with glucose substrate and hence promoted the formation of an activation complex.

  13. Immobilization of diastase α-amylase on nano zinc oxide.

    PubMed

    Antony, Navya; Balachandran, S; Mohanan, P V

    2016-11-15

    Diastase α-amylase extracted from malt, catalyses break down of starch into maltose. It is commonly used in food and fermentation industry. In the present study nano zinc oxide is used as support for this starch hydrolyzing enzyme. IR study revealed that the enzyme got adsorbed via electrostatic interaction with the functional groups on the support. The immobilized enzyme possessed a better heat-resistance than free enzyme. The kinetic parameters were determined using Lineweaver-Burk plot. The immobilized enzyme showed higher Km 2.08mg/ml than the free enzyme whose Km is 0.45±.05mg/ml. The Vmax of immobilized enzyme was about 2.92±.02mg/ml/min and that of free enzyme was 7.14±.02mg/ml/min, showing decrease in activity after immobilization. The immobilized enzyme showed 70% activity after 30days of storage while free enzyme lost its activity within 7days. About 80% of enzyme retained activity after 4 cycles of reuse. PMID:27283676

  14. Biodiesel production with immobilized lipase: A review.

    PubMed

    Tan, Tianwei; Lu, Jike; Nie, Kaili; Deng, Li; Wang, Fang

    2010-01-01

    Fatty acid alkyl esters, also called biodiesel, are environmentally friendly and show great potential as an alternative liquid fuel. Biodiesel is produced by transesterification of oils or fats with chemical catalysts or lipase. Immobilized lipase as the biocatalyst draws high attention because that process is "greener". This article reviews the current status of biodiesel production with immobilized lipase, including various lipases, immobilization methods, various feedstocks, lipase inactivation caused by short chain alcohols and large scale industrialization. Adsorption is still the most widely employed method for lipase immobilization. There are two kinds of lipase used most frequently especially for large scale industrialization. One is Candida antartica lipase immobilized on acrylic resin, and the other is Candida sp. 99-125 lipase immobilized on inexpensive textile membranes. However, to further reduce the cost of biodiesel production, new immobilization techniques with higher activity and stability still need to be explored. PMID:20580809

  15. Immobilized metal ion affinity chromatography.

    PubMed

    Yip, T T; Hutchens, T W

    1992-01-01

    Immobilized metal ion affinity chromatography (IMAC) (1,2) is also referred to as metal chelate chromatography, metal ion interaction chromatography, and ligand-exchange chromatography. We view this affinity separation technique as an intermediate between highly specific, high-affinity bioaffinity separation methods, and wider spectrum, low-specificity adsorption methods, such as ion exchange. The IMAC stationary phases are designed to chelate certain metal ions that have selectivity for specific groups (e.g., His residues) in peptides (e.g., 3-7) and on protein surfaces (8-13). The number of stationary phases that can be synthesized for efficient chelation of metal ions is unlimited, but the critical consideration is that there must be enough exposure of the metal ion to interact with the proteins, preferably in a biospecific manner. Several examples are presented in Fig. 1. The challenge to produce new immobilized chelating groups, including protein surface metal-binding domains (14,15) is being explored continuously. Table 1 presents a list of published procedures for the synthesis and use of stationary phases with immobilized chelating groups. This is by no means exhaustive, and is intended only to give an idea of the scope and versatility of IMAC. Fig. 1 Schematic illustration of several types of immobilized metal-chelating groups, including, iminodiacetate (IDA), tris(carboxymethyl) ethylenediamine (TED), and the metal-binding peptides (GHHPH)(n)G (where n = 1,2,3, and 5) (14,15). Table 1 Immobilized Chelating Groups and Metal Ions Used for Immobilized Metal Ion Affinity Chromatography Chelating group Suitable metal ions Reference Commercial source Immodiacetate Transitional1,2 Pharmacia LKB Pierce Sigma Boehringer Mannheim TosoHaas 2-Hydroxy-3[N-(2- pyrtdylmethyl) glycme]propyl Transitional3 Not available ?-Alky1 mtrilo triacetic acid Transitional4 Not available Carboxymethylated asparhc acid Ca(II)13 Not available Tris (carboxy- methyl) ethylene Diamme

  16. Rhizopus oryzae lipase immobilized on hierarchical mesoporous silica supports for transesterification of rice bran oil.

    PubMed

    Ramachandran, Prashanth; Narayanan, Guru Krupa; Gandhi, Sakthivel; Sethuraman, Swaminathan; Krishnan, Uma Maheswari

    2015-03-01

    The tunable textural properties of self-oriented mesoporous silica were investigated for their suitability as enzyme immobilization matrices to support transesterification of rice bran oil. Different morphologies of mesoporous silica (rod-like, rice-like, and spherical) were synthesized and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and nitrogen adsorption-desorption isotherms. The surface area, pore size, and ordered arrangement of the pores were found to influence the immobilization and activity of the enzyme in the mesopores. The immobilization in rod-like silica was highest with an immobilization efficiency of 63 % and exhibited minimal activity loss after immobilization. Functionalization of the mesoporous surface with ethyl groups further enhanced the enzyme immobilization. The free enzyme lost most of its activity at 50 °C while the immobilized enzyme showed activity even up to 60 °C. Transesterified product yield of nearly 82 % was obtained for 24 h of reaction with enzyme immobilized on ethyl-functionalized SBA-15 at an oil:methanol ratio of 1:3. Fourier transform infrared spectroscopy (FT-IR) and Gas chromatography-mass spectrometry (GC-MS) were used to characterize the transesterified product obtained. The reusability of the immobilized enzyme was studied for 3 cycles. PMID:25488500

  17. Immobilization of alkaline phosphatase on microporous nanofibrous fibrin scaffolds for bone tissue engineering.

    PubMed

    Osathanon, Thanaphum; Giachelli, Cecilia M; Somerman, Martha J

    2009-09-01

    Alkaline phosphatase (ALP) promotes bone formation by degrading inorganic pyrophosphate (PP(i)), an inhibitor of hydroxyapatite formation, and generating inorganic phosphate (P(i)), an inducer of hydroxyapatite formation. P(i) is a crucial molecule in differentiation and mineralization of osteoblasts. In this study, a method to immobilize ALP on fibrin scaffolds with tightly controllable pore size and pore interconnection was developed, and the biological properties of these scaffolds were characterized both in vitro and in vivo. Microporous, nanofibrous fibrin scaffolds (FS) were fabricated using a sphere-templating method. ALP was covalently immobilized on the fibrin scaffolds using 1-ethyl-3-(dimethylaminopropyl)carbodiimide hydrochloride (EDC). Scanning electron microscopic observation (SEM) showed that mineral was deposited on immobilized alkaline phosphatase fibrin scaffolds (immobilized ALP/FS) when incubated in medium supplemented with beta-glycerophosphate, suggesting that the immobilized ALP was active. Primary calvarial cells attached, spread and formed multiple layers on the surface of the scaffolds. Mineral deposition was also observed when calvarial cells were seeded on immobilized ALP/FS. Furthermore, cells seeded on immobilized ALP/FS exhibited higher osteoblast marker gene expression compared to control FS. Upon implantation in mouse calvarial defects, both the immobilized ALP/FS and FS alone treated group had higher bone volume in the defect compared to the empty defect control. Furthermore, bone formation in the immobilized ALP/FS treated group was statistically significant compared to FS alone group. However, the response was not robust. PMID:19501906

  18. Soybean hull peroxidase immobilization on macroporous glycidyl methacrylates with different surface characteristics.

    PubMed

    Prokopijevic, Milos; Prodanovic, Olivera; Spasojevic, Dragica; Stojanovic, Zeljko; Radotic, Ksenija; Prodanovic, Radivoje

    2014-05-01

    Soybean hull peroxidase (SHP, E.C. 1.11.1.7) was immobilized by a glutaraldehyde and periodate method onto series of macroporous copolymers of glycidyl methacrylate (GMA) and ethylene glycol dimethacrylate (EGDMA), poly(GMA-co-EGDMA) with various surface characteristics and pore size diameters ranging from 44 to 200 nm. Glutaraldehyde immobilization method and poly(GMA-co-EGDMA) named SGE 20/12 with pore sizes of 120 nm gave immobilized enzyme with highest specific activity of 25 U/g. Deactivation studies showed that immobilization increased stability of SHP and that surface characteristics of the used copolymer had a major influence on a stability of immobilized enzyme at high temperatures and in an organic solvent. The highest thermostability was obtained using the copolymer SGE 20/12 with pore size of 120 nm, while the highest stability in dioxane had SHP immobilized onto copolymer SGE 10/4 with pore size of 44 nm. Immobilized SHP showed a wider pH optimum as compared to the native enzyme especially at alkaline pH values and 3.2 times increased K m value for pyrogallol. After 6 cycles of repeated use in batch reactor, immobilized SHP retained 25 % of its original activity. Macroporous copolymers with different surface characteristics can be used for fine tuning of activity and stability of immobilized SHP to obtain a biocatalyst suitable for phenol oxidation or polymer synthesis in organic solvents. PMID:24061564

  19. Comparative evaluation of pumice stone as an alternative immobilization material for 1,3-propanediol production from waste glycerol by immobilized Klebsiella pneumoniae.

    PubMed

    Gonen, Cagdas; Gungormusler, Mine; Azbar, Nuri

    2012-12-01

    In this study, pumice stone (PS), which is a vastly available material in Turkey, was evaluated as an alternative immobilization material in comparison to other commercially available immobilization materials such as glass beads and polyurethane foam. All immobilized bioreactors resulted in much better 1,3-propanediol production from waste glycerol in comparison to the suspended cell culture bioreactor. It was also demonstrated that the locally available PS material is as good as the commercially available immobilization material. The maximum volumetric productivity (8.5 g L(-1) h(-1)) was obtained by the PS material, which is 220 % higher than the suspended cell system. Furthermore, the immobilized bioreactor system was much more robust against cell washout even at very low hydraulic retention time values. PMID:23079889

  20. Immobilization osteoporosis and active vitamin D: effect of active vitamin D analogs on the development of immobilization osteoporosis in rats.

    PubMed

    Izawa, Y; Makita, T; Hino, S; Hashimoto, Y; Kushida, K; Inoue, T; Orimo, H

    1981-01-01

    The therapeutic effects of vitamin D analogs, 1,24(R)-dihydroxycholecalciferol [1,24(R)-(OH)2D3], 1,24(S)-dihydroxycholecalciferol [1,24-(S)(OH)2D3], and 1,25-dihydroxycholecalciferol [1,25(OH)2D3] on immobilization osteoporosis were studied in rats. The right hind limb was immobilized through application of a plaster cast following the section of the sciatic nerve. The left hind limb was intact. Vitamin D analogs were orally administered for 6 weeks at dose levels of 0.02 and 0.10 micrograms/kg/day, respectively. The mean lengths of the immobilized femurs were not significantly different from those of the intact femurs in all the experimental groups. In the immobilized femur of animals treated with 1,24(R)(OH)2D3, 0.10 micrograms/kg, dry and ash weights were heavier and calcium and phosphorus contents greater than those in the nontreated group. Furthermore, the amount of calcified bone mass and the cortical thickness of the femurs of the immobilized limb in 1,24(OH)2D3-treated animals were greater than those in the nontreated animals. Treatment with 1,25(OH)2D3 at 0.10 micrograms/kg caused an increase of the bone mass in both immobilized and intact femurs when compared with those of the control group. It was concluded that the administration of 1,24(R)(OH)2D3 diminished the effect of immobilization in the development of osteoporosis without any side effects. PMID:6799174

  1. Immobilization of iodine in concrete

    DOEpatents

    Clark, Walter E.; Thompson, Clarence T.

    1977-04-12

    A method for immobilizing fission product radioactive iodine recovered from irradiated nuclear fuel comprises combining material comprising water, Portland cement and about 3-20 wt. % iodine as Ba(IO.sub.3).sub.2 to provide a fluid mixture and allowing the fluid mixture to harden, said Ba(IO.sub.3).sub.2 comprising said radioactive iodine. An article for solid waste disposal comprises concrete prepared by this method. BACKGROUND OF THE INVENTION This invention was made in the course of, or under a contract with the Energy Research and Development Administration. It relates in general to reactor waste solidification and more specifically to the immobilization of fission product radioactive iodine recovered from irradiated nuclear fuel for underground storage.

  2. Plutonium Immobilization Project -- Can loading

    SciTech Connect

    Kriikku, E.

    2000-01-18

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Project (PIP). The PIP scope includes unloading transportation containers, preparing the feed streams, converting the metal feed to an oxide, adding the ceramic precursors, pressing the pucks, inspecting pucks, and sintering pucks. The PIP scope also includes loading the pucks into metal cans, sealing the cans, inspecting the cans, loading the cans into magazines, loading magazines into Defense Waste Processing Facility (DWPF) canisters, and transporting the canisters to the DWPF. The DWPF fills the canister with a mixture of high level radioactive waste and glass for permanent storage. Due to the radiation, remote equipment must perform PIP operations in a contained environment.

  3. Plutonium Immobilization Can Inspection System

    SciTech Connect

    Kriikku, E.

    2000-12-12

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Plant (PIP) as part of Department of Energy's two-track approach for the disposition of weapons-usable plutonium. The PIP will utilize the ceramic can-in-canister technology in a process that mixes plutonium with ceramic formers and neutron absorbers, presses the mixture into a ceramic puck-like form, sinters the pucks in a furnace, loads the pucks into cans, and places the cans into large canisters. The canisters will subsequently be filled with high level waste glass in the Defense Waste Processing Facility for eventual disposal in a geologic repository. This paper will discuss the PIP can inspection components, control system, and test results.

  4. Immobilization of Candida rugosa lipase on sporopollenin from Lycopodium clavatum.

    PubMed

    Tutar, Havva; Yilmaz, Elif; Pehlivan, Erol; Yilmaz, Mustafa

    2009-10-01

    Sporopollenin is a natural polymer obtained from Lycopodium clavatum, which is highly stable with constant chemical structure and has high resistant capacity to chemical attack. In this study, immobilization of lipase from Candida rugosa (CRL) on sporopollenin by adsorption method is reported for the first time. Besides this, the enzyme adsorption capacity, activity and thermal stability of immobilized enzyme have also been investigated. It has been observed that under the optimum conditions (Spo-E((0.3))), the specific activity of the immobilized lipase on the sporopollenin by adsorption was 16.3U/mg protein, which is 0.46 times less than that of the free lipase (35.6U/mg protein). The pH and temperature of immobilized enzyme were optimized, which were 6.0 and 40 degrees C respectively. Kinetic parameters V(max) and K(m) were also determined for the immobilized lipase. It was observed that there is an increase of the K(m) value (7.54mM) and a decrease of the V(max) value (145.0U/mg-protein) comparing with that of the free lipase. PMID:19583977

  5. Knee joint immobilization decreases aggrecan gene expression in the meniscus.

    PubMed

    Djurasovic, M; Aldridge, J W; Grumbles, R; Rosenwasser, M P; Howell, D; Ratcliffe, A

    1998-01-01

    Aggrecan is the major proteoglycan of the meniscus, and its primary function is to give the meniscus its viscoelastic compressive properties. The objective of this study was to determine the effect of joint immobilization on aggrecan gene expression in the meniscus. The right hindlimbs of six mature beagles were knee cast-immobilized in 90 degrees of flexion and supported by a sling to prevent weightbearing, while the contralateral limb was left free to bear weight. The animals were sacrificed at 4 weeks, and the anterior and posterior halves of the medial and lateral menisci were analyzed separately. Analysis of aggrecan gene expression by quantitative polymerase chain reaction showed decreased aggrecan gene expression in menisci from immobilized knees (P < 0.01, two-way analysis of variance). Aggrecan gene expression decreased by a factor of 2 to 5.5 in the different regions examined. Analysis of the composition of the meniscus also showed decreased proteoglycan content and increased water content with immobilization (P < 0.05, two-way analysis of variance). These results show that joint immobilization can significantly affect meniscal cellular activity and composition and can therefore potentially affect meniscal function. PMID:9617414

  6. [Novel Immobilized Biocatalyst for Microbiological Synthesis of Pharmaceutical Steroids].

    PubMed

    Andryushina, V A; Karpova, N V; Druzhinina, A V; Stytsenko, T S; Podorozhko, E A; Ryabev, A N; Lozinskii, V I

    2015-01-01

    The steroid-transforming activity of free and immobilized cells of Pimelobacter simplex VKPM As-1632 entrapped in an operationally stable macroporous polyvinyl alcohol cryogel was studied. It was shown that the macroporous matrix of the carrier did not create any diffusional limitations for steroid access to the cells or the removal of the transformation products from them. The optimal conditions for the hydrocortisone 1,2-dehydration into prednisolone by free and immobilized cells were elucidated. The immobilized biocatalyst was obtained in a granulated form and used in 32 successive cycles of steroid transformation. The average cycle duration was 45 min, and the prednisolone yield of during the first 20 cycles was 98%. It was established that the immobilized cells of the actinobacteria P. simplex retained high steroid-transforming activity over all of the transformation cycles. The physicochemical and diffusion characteristics of the polyvinyl alcohol gels and its granules were determined, and their high stability during repeated cycles of steroid transformation was shown. The results indicated that P. simplex immobilized cells represent an effective catalyst suitable for multiple use. Biomass consumption decreased upon its use, and product isolation, as well as culture storage, was much easier. PMID:26596083

  7. In –Situ Spectroscopic Investigation of Immobilized Organometallic Catalysts

    SciTech Connect

    Davis, Robert, J.

    2007-11-14

    Immobilized organometallic catalysts, in principle, can give high rates and selectivities like homogeneous catalysts with the ease of separation enjoyed by heterogeneous catalysts. However, the science of immobilized organometallics has not been developed because the field lies at the interface between the homogeneous and heterogeneous catalysis communities. By assembling an interdisciplinary research team that can probe all aspects of immobilized organometallic catalyst design, the entire reacting system can be considered, where the transition metal complex, the complex-support interface and the properties of the support can all be considered simultaneously from both experimental and theoretical points of view. Researchers at Georgia Tech and the University of Virginia are studying the fundamental principles that can be used to understand and design future classes of immobilized organometallic catalysts. In the framework of the overall collaborative project with Georgia Tech, our work focused on (a) the X-ray absorption spectroscopy of an immobilized Pd-SCS-O complex (b) the mode of metal leaching from supported Pd catalysts during Heck catalysis and (c) the mode of deactivation of Jacobsen’s Co-salen catalysts during the hydrolytic kinetic resolution of terminal epoxides. Catalysts containing supported Pd pincer complexes, functionalized supports containing mercapto and amine groups, and oligomeric Co-salen catalysts were synthesized at Georgia Tech and sent to the University of Virginia. Incorporation of Pd onto several different kinds of supports (silica, mercapto-functionalized silica, zeolite Y) was performed at the University of Virginia.

  8. [Immobilization of heavy metal Pb2+ with geopolymer].

    PubMed

    Jin, Man-tong; Jin, Zan-fang; Huang, Cai-ju

    2011-05-01

    A series of geopolymers were synthesized by mixing metakaolinite, water glass, sodium hydroxide and water, and the lead ion solidification experiments were performed with the geopolymer. Then, the immobilization efficiency was characterized by monitoring the leaching concentration and compressive strength of solidified products. Additionally, the structure and properties of the solidified products were studied by X-ray diffraction (XRD), scan electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Furthermore, based on the analysis of immobilization efficiency, microstructure and mineral structure, the difference between geopolymer and cement on the performance of immobilizing heavy metals was discussed. The results of lead ion immobilization experiments showed that over 99.7% of heavy metal was captured by the geopolymer as the doping concentration of lead ion was less than 3%. Meanwhile, the compressive strength of the solidified product ranged from 40 MPa to 50 MPa. Furthermore, by using the same Pb2+ concentration, the geopolymer showed higher compressive strength and lower leaching concentration compared to the cement. Because lead ion participated in constitution of structure of geopolymer, or Pb2+ was adsorbed by the aluminium ions on the geopolymeric skeleton and held in geopolymer. However, cement mainly solidified lead ion by physical encapsulation and adsorption mechanism. Therefore, both from the compressive strength and leaching concentration and from the microstructure characterization as well as the mechanism of the geopolymerization reaction, the geopolymer has more advantages in immobilizing Pb2+ than the cement. PMID:21780604

  9. Spine Immobilizer for Accident Victims

    NASA Technical Reports Server (NTRS)

    Vykukal, H. C.; Lampson, K.

    1983-01-01

    Proposed conformal bladder filled with tiny spheres called "microballoons," enables spine of accident victim to be rapidly immobilized and restrained and permit victim to be safely removed from accident scene in extremely short time after help arrives. Microballoons expand to form rigid mass when pressure within bladder is less than ambient. Bladder strapped to victim is also strapped to rescue chair. Void between bladder and chair is filled with cloth wedges.

  10. Activity stabilization of Aspergillus niger and Escherichia coli phytases immobilized on allophanic synthetic compounds and montmorillonite nanoclays.

    PubMed

    Menezes-Blackburn, Daniel; Jorquera, Milko; Gianfreda, Liliana; Rao, Maria; Greiner, Ralf; Garrido, Elizabeth; de la Luz Mora, María

    2011-10-01

    The aim of this work was to study the stabilization of the activity of two commercial microbial phytases (Aspergillus niger and Escherichia coli) after immobilization on nanoclays and to establish optimal conditions for their immobilization. Synthetic allophane, synthetic iron-coated allophanes and natural montmorillonite were chosen as solid supports for phytase immobilization. Phytase immobilization patterns at different pH values were strongly dependent on both enzyme and support characteristics. After immobilization, the residual activity of both phytases was higher under acidic conditions. Immobilization of phytases increased their thermal stability and improved resistance to proteolysis, particularly on iron-coated allophane (6% iron oxide), which showed activation energy (E(a)) and activation enthalpy (ΔH(#)) similar to free enzymes. Montmorillonite as well as allophanic synthetic compounds resulted in a good support for immobilization of E. coli phytase, but caused a severe reduction of A. niger phytase activity. PMID:21856150

  11. Industrial applications of immobilized cells

    SciTech Connect

    Linko, P.; Linko, Y.Y.

    1984-01-01

    Although the application of the natural attraction of many microorganisms to surfaces has been applied in vinegar production since the early 1980s, and has long been utilized in waste water purification, the development of microbial cell immobilization techniques for special applications dates back only to the early 1960s. The immobilization may involve whole cells, cell fragments, or lysed cells. Whole cells may retain their metabolic activity with their complex multienzyme systems and cofactor regeneration mechanisms intact, or they may be killed in the process with only a few desired enzymes remaining active in the final biocatalyst. Cells may also be coimmobilized with an enzyme to carry out special reactions. Although relatively few industrial scale applications exist today, some are of very large scale. Current applications vary from relatively small scale steroid conversions to amino acid production and high fructose syrup manufacture. A vast number of potential applications are already known, and one of the most interesting applications may be in continuous fermentation such as ethanol production by immobilized living microorganisms. 373 references.

  12. A facile and effective immobilization of glucose oxidase on tannic acid modified CoFe2O4 magnetic nanoparticles.

    PubMed

    Altun, Seher; Çakıroğlu, Bekir; Özacar, Münteha; Özacar, Mahmut

    2015-12-01

    This article presents a study of glucose oxidase (GOx) immobilization by employing tannic acid (TA) modified-CoFe2O4 (CFO) magnetic nanoparticles which demonstrates novel aspect for enzyme immobilization. By using the strong protein and tannic acid binding, GOx immobilization was carried out via physical adsorption in a simpler way compared with the other immobilization methods which require various chemicals and complicated procedures which is difficult, expensive, time-consuming, and destructive to the enzyme structure. CFO was synthesized by hydrothermal synthesis and modified with TA to immobilize GOx. The immobilized GOx demonstrated maximum catalytic activity at pH 6.5 and 45 °C. The samples were characterized by vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential, and fourier transform infrared spectroscopy (FTIR), all of which confirm the surface modification of CFO and GOx immobilization. Also, field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD) were performed to demonstrate the surface morphology and chemical structure of samples. According to the Lineweaver-Burk plot, GOx possessed lower affinity to glucose after immobilization, and the Michelis-Menten constant (KM) of immobilized and free GOx were found to be 50.05 mM and 28.00 mM, respectively. The immobilized GOx showed excellent reusability, and even after 8 consecutive activity assay runs, the immobilized GOx maintained ca. 60% of its initial activity. PMID:26562188

  13. Venous Thrombosis Risk after Cast Immobilization of the Lower Extremity: Derivation and Validation of a Clinical Prediction Score, L-TRiP(cast), in Three Population-Based Case–Control Studies

    PubMed Central

    Nemeth, Banne; van Adrichem, Raymond A.; van Hylckama Vlieg, Astrid; Bucciarelli, Paolo; Martinelli, Ida; Baglin, Trevor; Rosendaal, Frits R.; le Cessie, Saskia; Cannegieter, Suzanne C.

    2015-01-01

    Background Guidelines and clinical practice vary considerably with respect to thrombosis prophylaxis during plaster cast immobilization of the lower extremity. Identifying patients at high risk for the development of venous thromboembolism (VTE) would provide a basis for considering individual thromboprophylaxis use and planning treatment studies. The aims of this study were (1) to investigate the predictive value of genetic and environmental risk factors, levels of coagulation factors, and other biomarkers for the occurrence of VTE after cast immobilization of the lower extremity and (2) to develop a clinical prediction tool for the prediction of VTE in plaster cast patients. Methods and Findings We used data from a large population-based case–control study (MEGA study, 4,446 cases with VTE, 6,118 controls without) designed to identify risk factors for a first VTE. Cases were recruited from six anticoagulation clinics in the Netherlands between 1999 and 2004; controls were their partners or individuals identified via random digit dialing. Identification of predictor variables to be included in the model was based on reported associations in the literature or on a relative risk (odds ratio) > 1.2 and p ≤ 0.25 in the univariate analysis of all participants. Using multivariate logistic regression, a full prediction model was created. In addition to the full model (all variables), a restricted model (minimum number of predictors with a maximum predictive value) and a clinical model (environmental risk factors only, no blood draw or assays required) were created. To determine the discriminatory power in patients with cast immobilization (n = 230), the area under the curve (AUC) was calculated by means of a receiver operating characteristic. Validation was performed in two other case–control studies of the etiology of VTE: (1) the THE-VTE study, a two-center, population-based case–control study (conducted in Leiden, the Netherlands, and Cambridge, United Kingdom

  14. Purification, immobilization, and characterization of nattokinase on PHB nanoparticles.

    PubMed

    Deepak, Venkataraman; Pandian, Suresh babu Ram Kumar; Kalishwaralal, Kalimuthu; Gurunathan, Sangiliyandi

    2009-12-01

    In this study, nattokinase was purified from Bacillus subtilis using ion exchange chromatography and immobilized upon polyhydroxybutyrate (PHB) nanoparticles. A novel strain isolated from industrial dairy waste was found to synthesize polyhydroxyalkanoates (PHA) and the strain was identified as Brevibacterium casei SRKP2. PHA granules were extracted from 48 h culture and the FT-IR analysis characterized them as PHB, a natural biopolymer from B. casei. Nanoprecipitation by solvent displacement technique was used to synthesize PHB nanoparticles. PHB nanoparticles were characterized using transmission electron microscopy and particle size ranged from 100-125 nm. Immobilization of nattokinase upon PHB nanoparticles resulted in a 20% increase in the enzyme activity. Immobilization also contributed to the enhanced stability of the enzyme. Moreover, the activity was completely retained on storage at 4 degrees C for 25 days. The method has proven to be highly simple and can be implemented to other enzymes also. PMID:19608412

  15. Immobilization of Polymeric Luminophor on Nanoparticles Surface.

    PubMed

    Bolbukh, Yuliia; Podkoscielna, Beata; Lipke, Agnieszka; Bartnicki, Andrzej; Gawdzik, Barbara; Tertykh, Valentin

    2016-12-01

    Polymeric luminophors with reduced toxicity are of the priorities in the production of lighting devices, sensors, detectors, bioassays or diagnostic systems. The aim of this study was to develop a method of immobilization of the new luminophor on a surface of nanoparticles and investigation of the structure of the grafted layer. Monomer 2,7-(2-hydroxy-3-methacryloyloxypropoxy)naphthalene (2,7-NAF.DM) with luminophoric properties was immobilized on silica and carbon nanotubes in two ways: mechanical mixing with previously obtained polymer and by in situ oligomerization with chemisorption after carrier's modification with vinyl groups. The attached polymeric (or oligomeric) surface layer was studied using thermal and spectral techniques. Obtained results confirm the chemisorption of luminophor on the nanotubes and silica nanoparticles at the elaborated synthesis techniques. The microstructure of 2,7-NAF.DM molecules after chemisorption was found to be not changed. The elaborated modification approach allows one to obtain nanoparticles uniformly covered with polymeric luminophor. PMID:27090657

  16. Analysis of alternatives for immobilized low activity waste disposal

    SciTech Connect

    Burbank, D.A.

    1997-10-28

    This report presents a study of alternative disposal system architectures and implementation strategies to provide onsite near-surface disposal capacity to receive the immobilized low-activity waste produced by the private vendors. The analysis shows that a flexible unit strategy that provides a suite of design solutions tailored to the characteristics of the immobilized low-activity waste will provide a disposal system that best meets the program goals of reducing the environmental, health, and safety impacts; meeting the schedule milestones; and minimizing the life-cycle cost of the program.

  17. Maltodextrin hydrolysis in a fluidized-bed immobilized enzyme reactor

    SciTech Connect

    Vallat, I.; Monsan, P.; Riba, J.P.

    1986-02-01

    The present work deals with maltodextrin hydrolysis by glucoamylase immobilized onto corn stover in a fluidized bed reactor. An industrial enzyme preparation was convalently grafted onto corn stover, yielding an activity of up to 372 U/g and 1700 U/g for support particle sizes of 0.8 and 0.2 mm, respectively. A detailed kinetic study, using a differntial reactor, allowed the characterization of the influence of mass transfer resistance on the reaction catalyzed by immobilized glucoamylase. A simple and general mathematical model was then developed to describe the experimental conversion data and found to be vaild.

  18. New monolithic chromatographic supports for macromolecules immobilization: challenges and opportunities.

    PubMed

    Calleri, E; Ambrosini, S; Temporini, C; Massolini, G

    2012-10-01

    This mini-review reports on some recent advances in the field of immobilized protein employing both silica and polymer-based monoliths as supports, and their application in affinity chromatography and immobilized enzyme reactors (IMERs) developments. The major emphasis is put on some interesting challenges and opportunities related to the development of new monolithic affinity supports based on biofriendly sol-gel inorganic monoliths with entrapped proteins and on organic monolithic supports with improved hydrophilicity for IMERs development in proteomic studies. The ease of preparation of monoliths and the multitude of functionalization techniques, make monoliths interesting for an increasing number of biochemical and medical applications. PMID:22386208

  19. Utilization of immobilized urease for waste water treatment

    NASA Technical Reports Server (NTRS)

    Husted, R. R.

    1974-01-01

    The feasibility of using immobilized urease for urea removal from waste water for space system applications is considered, specifically the elimination of the urea toxicity problem in a 30-day Orbiting Frog Otolith (OFO) flight experiment. Because urease catalyzes the hydrolysis of urea to ammonia and carbon dioxide, control of their concentrations within nontoxic limits was also determined. The results of this study led to the use of free urease in lieu of the immobilized urease for controlling urea concentrations. An ion exchange resin was used which reduced the NH3 level by 94% while reducing the sodium ion concentration only 10%.

  20. Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres.

    PubMed

    Ibrahim, Abdelnasser Salah Shebl; Al-Salamah, Ali A; El-Toni, Ahmed M; Almaary, Khalid S; El-Tayeb, Mohamed A; Elbadawi, Yahya B; Antranikian, Garabed

    2016-01-01

    The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS-NH₂ nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher V(max), k(cat) and k(cat)/K(m), than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media. PMID:26840303

  1. Enhancement of Alkaline Protease Activity and Stability via Covalent Immobilization onto Hollow Core-Mesoporous Shell Silica Nanospheres

    PubMed Central

    Ibrahim, Abdelnasser Salah Shebl; Al-Salamah, Ali A.; El-Toni, Ahmed M.; Almaary, Khalid S.; El-Tayeb, Mohamed A.; Elbadawi, Yahya B.; Antranikian, Garabed

    2016-01-01

    The stability and reusability of soluble enzymes are of major concerns, which limit their industrial applications. Herein, alkaline protease from Bacillus sp. NPST-AK15 was immobilized onto hollow core-mesoporous shell silica (HCMSS) nanospheres. Subsequently, the properties of immobilized proteases were evaluated. Non-, ethane- and amino-functionalized HCMSS nanospheres were synthesized and characterized. NPST-AK15 was immobilized onto the synthesized nano-supports by physical and covalent immobilization approaches. However, protease immobilization by covalent attachment onto the activated HCMSS–NH2 nanospheres showed highest immobilization yield (75.6%) and loading capacity (88.1 μg protein/mg carrier) and was applied in the further studies. In comparison to free enzyme, the covalently immobilized protease exhibited a slight shift in the optimal pH from 10.5 to 11.0, respectively. The optimum temperature for catalytic activity of both free and immobilized enzyme was seen at 60 °C. However, while the free enzyme was completely inactivated when treated at 60 °C for 1 h the immobilized enzyme still retained 63.6% of its initial activity. The immobilized protease showed higher Vmax, kcat and kcat/Km, than soluble enzyme by 1.6-, 1.6- and 2.4-fold, respectively. In addition, the immobilized protease affinity to the substrate increased by about 1.5-fold. Furthermore, the enzyme stability in various organic solvents was significantly enhanced upon immobilization. Interestingly, the immobilized enzyme exhibited much higher stability in several commercial detergents including OMO, Tide, Ariel, Bonux and Xra by up to 5.2-fold. Finally, the immobilized protease maintained significant catalytic efficiency for twelve consecutive reaction cycles. These results suggest the effectiveness of the developed nanobiocatalyst as a candidate for detergent formulation and peptide synthesis in non-aqueous media. PMID:26840303

  2. Drop drying on surfaces determines chemical reactivity - the specific case of immobilization of oligonucleotides on microarrays

    PubMed Central

    2013-01-01

    Background Drop drying is a key factor in a wide range of technical applications, including spotted microarrays. The applied nL liquid volume provides specific reaction conditions for the immobilization of probe molecules to a chemically modified surface. Results We investigated the influence of nL and μL liquid drop volumes on the process of probe immobilization and compare the results obtained to the situation in liquid solution. In our data, we observe a strong relationship between drop drying effects on immobilization and surface chemistry. In this work, we present results on the immobilization of dye labeled 20mer oligonucleotides with and without an activating 5′-aminoheptyl linker onto a 2D epoxysilane and a 3D NHS activated hydrogel surface. Conclusions Our experiments identified two basic processes determining immobilization. First, the rate of drop drying that depends on the drop volume and the ambient relative humidity. Oligonucleotides in a dried spot react unspecifically with the surface and long reaction times are needed. 3D hydrogel surfaces allow for immobilization in a liquid environment under diffusive conditions. Here, oligonucleotide immobilization is much faster and a specific reaction with the reactive linker group is observed. Second, the effect of increasing probe concentration as a result of drop drying. On a 3D hydrogel, the increasing concentration of probe molecules in nL spotting volumes accelerates immobilization dramatically. In case of μL volumes, immobilization depends on whether the drop is allowed to dry completely. At non-drying conditions, very limited immobilization is observed due to the low oligonucleotide concentration used in microarray spotting solutions. The results of our study provide a general guideline for microarray assay development. They allow for the initial definition and further optimization of reaction conditions for the immobilization of oligonucleotides and other probe molecule classes to different

  3. pH-dependent immobilization of urease on glutathione-capped gold nanoparticles.

    PubMed

    Garg, Seema; De, Arnab; Mozumdar, Subho

    2015-05-01

    Urease is a nickel-dependent metalloenzyme that catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. Although the enzyme serves a significant role in several detoxification and analytical processes, its usability is restricted due to high cost, availability in small amounts, instability, and a limited possibility of economic recovery from a reaction mixture. Hence, there is a need to develop an efficient, simple, and reliable immobilization strategy for the enzyme. In this study, the carboxyl terminated surface of glutathione-capped gold nanoparticles have been utilized as a solid support for the covalent attachment of urease. The immobilization has been carried out at different pH conditions so as to elucidate its effect on the immobilization efficiency and enzyme bioactivity. The binding of the enzyme has been quantitatively and qualitatively analyzed through techniques like ultraviolet-visible spectroscopy, intrinsic steady state fluorescence, and circular dichorism. The bioactivity of the immobilized enzyme was investigated with respect to the native enzyme under different thermal conditions. Recyclability and shelf life studies of the immobilized enzyme have also been carried out. Results reveal that the immobilization is most effective at pH of 7.4 followed by that in an acidic medium and is least in alkaline environment. The immobilized enzyme also exhibits enhance activity in comparison to the native form at physiological temperature. The immobilized urease (on gold glutathione nanoconjugates surface) can be effectively employed for biosensor fabrication, immunoassays and as an in vivo diagnostic tool in the future. PMID:25227875

  4. Immobilization and controlled release of β-galactosidase from chitosan-grafted hydrogels.

    PubMed

    Facin, Bruno R; Moret, Bruna; Baretta, Dilmar; Belfiore, Laurence A; Paulino, Alexandre T

    2015-07-15

    Chitosan-grafted hydrogels were employed for immobilization and controlled released of β-galactosidase. These hydrogels containing immobilized enzymes were employed to simulate the production of lactose-free food and controlled release of β-galactosidase into lactose-intolerant individuals. The degree of swelling, efficiency of immobilization (i.e., fractional uptake of enzyme), and controlled release were studied as a function of pH and temperature. The degrees of swelling decreased in acidic media: 49.4 g absorbed water per g hydrogel at pH 7.0, and 8.4 g absorbed water per g hydrogel at pH 3.5. The immobilization efficiency was 19%, indicating that chitosan-grafted hydrogels are promising matrices for enzyme adsorption and immobilization. Cyclic experiments reveal that chitosan-grafted hydrogels containing immobilized enzymes can be reused several times without introducing additional enzyme prior to each cycle. There is no significant decrease in the activity of the immobilized enzyme during reutilization studies. All results were conducted in triplicate by considering t-tests at a 95% significance level. Analysis of β-galactosidase activity and controlled release reveals that chitosan-grafted hydrogels containing immobilized enzymes are useful for the production of lactose-free food and controlled enzyme release with high performance. PMID:25722137

  5. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO₂ nanoparticles from aqueous media.

    PubMed

    Shaker, Medhat A; Yakout, Amr A

    2016-02-01

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51±3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, (1)H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r(2)) and non-linear Chi-square (χ(2)) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters. PMID:26520475

  6. Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO2 nanoparticles from aqueous media

    NASA Astrophysics Data System (ADS)

    Shaker, Medhat A.; Yakout, Amr A.

    2016-02-01

    Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51 ± 3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, 1H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r2) and non-linear Chi-square (χ2) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

  7. Electrochemical impedance spectroscopy study on polymerization of L-lysine on electrode surface and its application for immobilization and detection of suspension cells.

    PubMed

    Huang, Baozhen; Jia, Ningming; Chen, Lina; Tan, Liang; Yao, Shouzhuo

    2014-07-15

    Poly-L-lysine (PLL), which has been employed as a conductive polymer in the construction of some electrochemical sensors, can be prepared using L-lysine by cyclic voltammetry (CV) with a wide potential range. However, the presented explanation and description about its polymerization mechanism seems oversimplified because the self-reaction of electrode and the electrolysis of solvent at high potential are ignored. This work presents an intensive investigation on the relevant reactions during the process of PLL-polymerization using CV, X-ray photoelectron spectroscopy, Fourier transform-infrared spectroscopy, and electrochemical impedance spectroscopy. At a higher positive potential, the transfer from lysine molecules to cation radicals and the polymerization reaction on the glassy carbon electrode (GCE) could be achieved, accompanied by the activation of GCE, the formation of oxygen-containing functional groups, and the generation of oxygen derived from the oxidation of water. The adsorbed oxygen had a seriously negative effect on the formation of PLL unless it suffered reduction at a lower negative potential. The charge transfer through the electrochemical polymerized PLL film was seriously hindered by the immobilization of suspension cells due to the electrostatic interaction. The charge-transfer resistance difference (ΔR(ct)) was increased with the enhancement of the cell number (N(cells)) and the 1/ΔR(ct) value displayed a linear response with 1/N(cells) in the range of 5.0 × 10(2)-1.0 × 10(5) cells with a detection limit of 180 cells estimated at a signal-to-noise ratio of 3. A sensitive electrochemical sensor for the quantitative detection of suspension cells was developed. PMID:24939429

  8. Drug absorption in vitro model: filter-immobilized artificial membranes. 2. Studies of the permeability properties of lactones in Piper methysticum Forst.

    PubMed

    Avdeef, A; Strafford, M; Block, E; Balogh, M P; Chambliss, W; Khan, I

    2001-12-01

    The assessment of transport properties of 23 drug and natural product molecules was made using the in vitro model based on filter-immobilized artificial membranes (filter-IAM), assembled from phosphatidylcholine in dodecane, in buffer solutions at pH 7.4. Five of the compounds were lactones extracted from the roots of the kava-kava plant. Experiments were designed to test the effects of stirring (0-600 rpm) during assays and the effects of varying the assay times (2-15 h). The highly mobile kava lactones permeated in the order dihydromethisticin (40)>yangonin (37)>kavain (34)>methisticin (32)>desmethoxyyangonin (26), the numbers in parentheses being the measured effective permeabilities in units of 10(-6) cm/s. By comparison, commercial drugs ranked: phenazopyridine (35)>testosterone (19)>propranolol (13)>ketoconazole (6.3)>piroxicam (2.2)>caffeine (1.7)>metoprolol (0.8)>terbutaline (0.01). In addition to permeability measurements, membrane retention of compounds was determined. Yangonin, desmethoxyyangonin, ketoconazole, and phenazopyridine were more than 60% retained by the artificial membranes containing phospholipids. Stirring during assay significantly increased the observed permeabilities for highly mobile molecules, but had minimal impact on the poorly permeable molecules. The influence of hydrogen bonding was explored by determining permeabilities using filters coated with dodecane free of phospholipids. In the filter-IAM method, concentrations were determined by microtitre plate UV spectrophotometry and by LC-MS. Higher-throughput was achieved with direct UV by the use of 96-well microtitre plate formats and with LC-MS by the use of cassette dosing (five-in-one). PMID:11684401

  9. Synthesis and heavy metal immobilization behaviors of slag based geopolymer.

    PubMed

    Yunsheng, Zhang; Wei, Sun; Qianli, Chen; Lin, Chen

    2007-05-01

    In this paper, two aspects of studies are carried out: (1) synthesis of geopolymer by using slag and metakaolin; (2) immobilization behaviors of slag based geopolymer in a presence of Pb and Cu ions. As for the synthesis of slag based geopolymer, four different slag content (10%, 30%, 50%, 70%) and three types of curing regimes (standard curing, steam curing and autoclave curing) are investigated to obtain the optimum synthesis condition based on the compressive and flexural strength. The testing results showed that geopolymer mortar containing 50% slag that is synthesized at steam curing (80 degrees C for 8h), exhibits higher mechanical strengths. The compressive and flexural strengths of slag based geopolymer mortar are 75.2 MPa and 10.1 MPa, respectively. Additionally, Infrared (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques are used to characterize the microstructure of the slag based geopolymer paste. IR spectra show that the absorptive band at 1086 cm(-1) shifts to lower wave number around 1007 cm(-1), and some six-coordinated Als transforms into four-coordination during the synthesis of slag based geopolymer paste. The resulting slag based geopolymeric products are X-ray amorphous materials. SEM observation shows that it is possible to have geopolymeric gel and calcium silicate hydrate (C-S-H) gel forming simultaneously within slag based geopolymer paste. As for immobilization of heavy metals, the leaching tests are employed to investigate the immobilization behaviors of the slag based geopolymer mortar synthesized under the above optimum condition. The leaching tests show that slag based geopolymer mortar can effectively immobilize Cu and Pb heavy metal ions, and the immobilization efficiency reach 98.5% greater when heavy metals are incorporated in the slag geopolymeric matrix in the range of 0.1-0.3%. The Pb exhibits better immobilization efficiency than the Cu in the case of large dosages of heavy metals. PMID:17034943

  10. Immobilization of enzymes: a literature survey.

    PubMed

    Brena, Beatriz; González-Pombo, Paula; Batista-Viera, Francisco

    2013-01-01

    The term immobilized enzymes refers to "enzymes physically confined or localized in a certain defined region of space with retention of their catalytic activities, and which can be used repeatedly and continuously." Immobilized enzymes are currently the subject of considerable interest because of their advantages over soluble enzymes. In addition to their use in industrial processes, the immobilization techniques are the basis for making a number of biotechnology products with application in diagnostics, bioaffinity chromatography, and biosensors. At the beginning, only immobilized single enzymes were used, after 1970s more complex systems including two-enzyme reactions with cofactor regeneration and living cells were developed. The enzymes can be attached to the support by interactions ranging from reversible physical adsorption and ionic linkages to stable covalent bonds. Although the choice of the most appropriate immobilization technique depends on the nature of the enzyme and the carrier, in the last years the immobilization technology has increasingly become a matter of rational design. As a consequence of enzyme immobilization, some properties such as catalytic activity or thermal stability become altered. These effects have been demonstrated and exploited. The concept of stabilization has been an important driving force for immobilizing enzymes. Moreover, true stabilization at the molecular level has been demonstrated, e.g., proteins immobilized through multipoint covalent binding. PMID:23934795

  11. Immobilized lipid-bilayer materials

    DOEpatents

    Sasaki, Darryl Y.; Loy, Douglas A.; Yamanaka, Stacey A.

    2000-01-01

    A method for preparing encapsulated lipid-bilayer materials in a silica matrix comprising preparing a silica sol, mixing a lipid-bilayer material in the silica sol and allowing the mixture to gel to form the encapsulated lipid-bilayer material. The mild processing conditions allow quantitative entrapment of pre-formed lipid-bilayer materials without modification to the material's spectral characteristics. The method allows for the immobilization of lipid membranes to surfaces. The encapsulated lipid-bilayer materials perform as sensitive optical sensors for the detection of analytes such as heavy metal ions and can be used as drug delivery systems and as separation devices.

  12. Tunable control of antibody immobilization using electric field

    PubMed Central

    Emaminejad, Sam; Javanmard, Mehdi; Gupta, Chaitanya; Chang, Shuai; Davis, Ronald W.; Howe, Roger T.

    2015-01-01

    The controlled immobilization of proteins on solid-state surfaces can play an important role in enhancing the sensitivity of both affinity-based biosensors and probe-free sensing platforms. Typical methods of controlling the orientation of probe proteins on a sensor surface involve surface chemistry-based techniques. Here, we present a method of tunably controlling the immobilization of proteins on a solid-state surface using electric field. We study the ability to orient molecules by immobilizing IgG molecules in microchannels while applying lateral fields. We use atomic force microscopy to both qualitatively and quantitatively study the orientation of antibodies on glass surfaces. We apply this ability for controlled orientation to enhance the performance of affinity-based assays. As a proof of concept, we use fluorescence detection to indirectly verify the modulation of the orientation of proteins bound to the surface. We studied the interaction of fluorescently tagged anti-IgG with surface immobilized IgG controlled by electric field. Our study demonstrates that the use of electric field can result in more than 100% enhancement in signal-to-noise ratio compared with normal physical adsorption. PMID:25650429

  13. Erosion depth of sand from an immobile gravel bed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract This study was conducted to provide information on the depth of erosion of sand (D50 = 0.3, 0.9 mm) from immobile gravel (D50 = 36.1 mm) under steady uniform flows with bed shear stresses from 0.1 to 0.9 of that required to entrain the gravel. This situation, often encountered downstream o...

  14. Immobilization of Pseudomonas sp. DG17 onto sodium alginate–attapulgite–calcium carbonate

    PubMed Central

    Wang, Hong Qi; Hua, Fei; Zhao, Yi Cun; Li, Yi; Wang, Xuan

    2014-01-01

    A strain of Pseudomonas sp. DG17, capable of degrading crude oil, was immobilized in sodium alginate–attapulgite–calcium carbonate for biodegradation of crude oil contaminated soil. In this work, proportion of independent variables, the laboratory immobilization parameters, the micromorphology and internal structure of the immobilized granule, as well as the crude oil biodegradation by sodium alginate–attapulgite–calcium carbonate immobilized cells and sodium alginate–attapulgite immobilized cells were studied to build the optimal immobilization carrier and granule-forming method. The results showed that the optimal concentrations of sodium alginate–attapulgite–calcium carbonate and calcium chloride were 2.5%–3.5%, 0.5%–1%, 3%–7% and 2%–4%, respectively. Meanwhile, the optimal bath temperature, embedding cell amount, reaction time and multiplication time were 50–60 °C, 2%, 18 h and 48 h, respectively. Moreover, biodegradation was enhanced by immobilized cells with a total petroleum hydrocarbon removal ranging from 33.56% ± 3.84% to 56.82% ± 3.26% after 20 days. The SEM results indicated that adding calcium carbonate was helpful to form internal honeycomb-like pores in the immobilized granules. PMID:26019567

  15. Conformational flexibility of a model protein upon immobilization on self-assembled monolayers.

    PubMed

    Bigdeli, Saharnaz; Talasaz, AmirAli H; Ståhl, Patrik; Persson, Henrik H J; Ronaghi, Mostafa; Davis, Ronald W; Nemat-Gorgani, Mohsen

    2008-05-01

    The present study reports on the retention of conformational flexibility of a model allosteric protein upon immobilization on self-assembled monolayers (SAMs) on gold. Organothiolated SAMs of different compositions were utilized for adsorptive and covalent attachment of bovine liver glutamate dehydrogenase (GDH), a well-characterized allosteric enzyme. Sensitive fluorimetric assays were developed to determine immobilization capacity, specific activity, and allosteric properties of the immobilized preparations as well as the potential for repeated use and continuous catalytic transformations. The allosteric response of the free and immobilized forms towards ADP, L-leucine and high concentrations of NAD(+), some of the well-known activators for this enzyme, were determined and compared. The enzyme immobilized by adsorption or chemical binding responded similarly to the activators with a greater degree of activation, as compared to the free form. Also loss of activity involving the two immobilization procedures were similar, suggesting that residues essential for catalytic activity or allosteric properties of GDH remained unchanged in the course of chemical modification. A recently established method was used to predict GDH orientation upon immobilization, which was found to explain some of the experimental results presented. The general significance of these observations in connection with retention of native properties of protein structures upon immobilization on SAMs is discussed. PMID:18078298

  16. Influence of acetylcholinesterase immobilization on the photoluminescence properties of mesoporous silicon surface

    NASA Astrophysics Data System (ADS)

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2014-07-01

    Acetylcholinesterase immobilized p-type porous silicon surface was prepared by covalent attachment. The immobilization procedure was based on support surface chemical oxidation, silanization, surface activation with cyanuric chloride and finally covalent attachment of free enzyme on the cyanuric chloride activated porous silicon surface. Different pore diameter of porous silicon samples were prepared by electrochemical etching in HF based electrolyte solution and appropriate sample was selected suitable for enzyme immobilization with maximum trapping ability. The surface modification was studied through field emission scanning electron microscope, EDS, FT-IR analysis, and photoluminescence measurement by utilizing the fluctuation in the photoluminescence of virgin and enzyme immobilized porous silicon surface. Porous silicon showed strong photoluminescence with maximum emission at 643 nm and immobilization of acetylcholinesterase on porous silicon surface cause considerable increment on the photoluminescence of porous silicon material while acetylcholinesterase free counterpart did not exhibit any fluorescence in the range of 635-670 nm. The activities of the free and immobilized enzymes were evaluated by spectrophotometric method by using neostigmine methylsulfate as standard enzyme inhibitor. The immobilized enzyme exhibited considerable response toward neostigmine methylsulfate in a dose dependent manner comparable with that of its free counterpart alongside enhanced stability, easy separation from the reaction media and significant saving of enzyme. It was believed that immobilized enzyme can be exploited in organic and biomolecule synthesis possessing technical and economical prestige over free enzyme and prominence of easy separation from the reaction mixture.

  17. Cagelike mesoporous silica encapsulated with microcapsules for immobilized laccase and 2, 4-DCP degradation.

    PubMed

    Yang, Junya; Huang, Yan; Yang, Yuxiang; Yuan, Hongming; Liu, Xiangnong

    2015-12-01

    In this study, cage-like mesoporous silica was used as the carrier to immobilize laccase by a physical approach, followed by encapsulating with chitosan/alginate microcapsule membranes to form microcapsules of immobilized laccase based on layer-by-layer technology. The relationship between laccase activity recovery/leakage rate and the coating thickness was simultaneously investigated. Because the microcapsule layers have a substantial network of pores, they act as semipermeable membranes, while the laccase immobilized inside the microcapsules acts as a processing plant for degradation of 2,4-dichlorophenol. The microcapsules of immobilized laccase were able to degrade 2,4-dichlorophenol within a wide range of 2,4-dichlorophenol concentration, temperature and pH, with mean degradation rate around 62%. Under the optimal conditions, the thermal stability and reusability of immobilized laccase were shown to be improved significantly, as the removal rate and degradation rate remained over 40.2% and 33.8% respectively after 6cycles of operation. Using mass spectrometry (MS) and nuclear magnetic resonance (NMR), diisobutyl phthalate and dibutyl phthalate were identified as the products of 2,4-dichlorophenol degradation by the microcapsules of immobilized laccase and laccase immobilized by a physical approach, respectively, further demonstrating the degradation mechanism of 2,4-dichlorophenol by microcapsule-immobilized laccase. PMID:26702968

  18. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart.

    PubMed

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4-9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  19. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

    PubMed Central

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  20. Facile synthesis of amino-silane modified superparamagnetic Fe3O4 nanoparticles and application for lipase immobilization.

    PubMed

    Cui, Yanjun; Li, Yanfeng; Yang, Yong; Liu, Xiao; Lei, Lin; Zhou, Lincheng; Pan, Fei

    2010-10-01

    In present study, a facile prepared nano-sized magnetic support was successfully synthesized. Then this support was applied for lipase immobilization using glutaraldehyde as a coupling agent. Experimental data showed that the immobilized lipase exhibited good thermal stability and reusability. The lipase loading amount and activity recovery were found to be 43.6 mg/g support and 58.2%. Kinetic studies suggested it an acceptable degree of specificity retention for an immobilization process. PMID:20638425

  1. Viability, ultrastructure and cytokinin metabolism of free and immobilized tobacco chloroplasts.

    PubMed

    Polanská, Lenka; Vicánková, Anna; Dobrev, Petre I; Cková, Ivana Macháv; Vanková, Radomíra

    2004-10-01

    Cytokinins play a decisive role in regulation of plastid development and differentiation, but their metabolism in plastids is not known. Metabolic studies using intact chloroplasts are prevented by their instability once they are isolated from leaf cells. Chloroplasts of Nicotiana tabacum L. cv. Petit Havana SR1 were therefore immobilized into low-viscosity alginate. Their intactness was assessed by a glyceraldehyde-3-phosphate dehydrogenase assay which indicated that free chloroplasts totally disintegrated within 7 h, while more than 50% of immobilized chloroplasts remained intact after 24 h. The immobilization had no marked impact on ultrastructure and postponed final destruction. The metabolite profile was similar in free and immobilized chloroplasts after 4 h incubation with tritiated zeatin. Nevertheless, the yield of conversion products decreased twice in immobilized chloroplasts, which was probably the outcome of mass transfer limitations and/or the sorption to polysaccharide matrix. PMID:15604795

  2. Immobilization of a Plant Lipase from Pachira aquatica in Alginate and Alginate/PVA Beads

    PubMed Central

    Bonine, Bárbara M.; Polizelli, Patricia Peres; Bonilla-Rodriguez, Gustavo O.

    2014-01-01

    This study reports the immobilization of a new lipase isolated from oleaginous seeds of Pachira aquatica, using beads of calcium alginate (Alg) and poly(vinyl alcohol) (PVA). We evaluated the morphology, number of cycles of reuse, optimum temperature, and temperature stability of both immobilization methods compared to the free enzyme. The immobilized enzymes were more stable than the free enzyme, keeping 60% of the original activity after 4 h at 50°C. The immobilized lipase was reused several times, with activity decreasing to approximately 50% after 5 cycles. Both the free and immobilized enzymes were found to be optimally active between 30 and 40°C. PMID:24818012

  3. Effect of consecutive cooling and immobilization on catecholamine metabolism in rat tissues

    NASA Technical Reports Server (NTRS)

    Matlina, E. S.; Waysman, S. M.; Zaydner, I. G.; Kogan, B. M.; Nozdracheva, L. V.

    1979-01-01

    The combined effect of two stressor stimuli--cooling and immobilization--acting successively on the sympathetic-adrenaline system was studied experimentally in rats that were cooled for 8 hours at 7 C on the first day and immobilized for 6 hours on the next day. The biochemical and histochemical methods used and the experimental technique involved are described in detail. The following conclusions were formulated: (1) the successive action of cooling and immobilization results in a stronger decrease in the adrenaline and noradrenaline content in the adrenal gland than that which could be due to a simple summation of the cooling and immobilization effects; (2) successive cooling and immobilization are followed by activation of catecholamine synthesis in the adrenal gland; and (3) 1-DOPA administration (45 mg/kg 3 times in 2 days) intraabdominally activated catecholamine synthesis in the adrenal glands in both the control and test animals.

  4. Immobilization of Streptomyces thermotolerans 11432 on polyurethane foam to improve production of acetylisovaleryltylosin.

    PubMed

    Zhu, Hongji; Wang, Weihua; Liu, Jiaheng; Caiyin, Qinggele; Qiao, Jianjun

    2015-01-01

    In this study, polyurethane foam (PUF) was chemically treated to immobilize Streptomyces thermotolerans 11432 for semi-continuous production of acetylisovaleryltylosin (AIV). Based on experimental results, positive cross-linked PUF (PCPUF) was selected as the most effective carrier according to immobilized cell mass. The effect of adsorption time on immobilized mass was investigated. AIV concentration (33.54 mg/l) in batch fermentations with immobilized cells was higher than with free cells (20.34 mg/l). In repeated batch fermentations with immobilized S. thermotolerans 11432 using PCPUF cubes, high AIV concentrations and conversion rates were attained, ranging from 25.56 to 34.37 mg/l and 79.93 to 86.31 %, respectively. Significantly, this method provides a feasible strategy for efficient AIV production and offers the potential for large-scale production. PMID:25413211

  5. Site-selective protein immobilization by covalent modification of GST fusion proteins.

    PubMed

    Zhou, Yiqing; Guo, Tianlin; Tang, Guanghui; Wu, Hui; Wong, Nai-Kei; Pan, Zhengying

    2014-11-19

    The immobilization of functional proteins onto solid supports using affinity tags is an attractive approach in recent development of protein microarray technologies. Among the commonly used fusion protein tags, glutathione S-transferase (GST) proteins have been indispensable tools for protein-protein interaction studies and have extensive applications in recombinant protein purification and reversible protein immobilization. Here, by utilizing pyrimidine-based small-molecule probes with a sulfonyl fluoride reactive group, we report a novel and general approach for site-selective immobilization of Schistosoma japonicum GST (sjGST) fusion proteins through irreversible and specific covalent modification of the tyrosine-111 residue of the sjGST tag. As demonstrated by sjGST-tagged eGFP and sjGST-tagged kinase activity assays, this immobilization approach offers the advantages of high immobilization efficiency and excellent retention of protein structure and activity. PMID:25340706

  6. Stabilization of α-amylase by using anionic surfactant during the immobilization process

    NASA Astrophysics Data System (ADS)

    El-Batal, A. I.; Atia, K. S.; Eid, M.

    2005-10-01

    This work describes the entrapment of α-amylase into butylacrylate-acrylic acid copolymer (BuA/AAc) using γ irradiation. The effect of an anionic surfactant (AOT), the reuse efficiency, and kinetic behavior of immobilized α-amylase were studied. Covering of α-amylase with bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) made the enzyme more stable than the uncovered form. The hydrolytic activity of the pre-coated immobilized α-amylase was increased below the critical micelle concentration (cmc) (10 mmol/L). The results showed an increase in the relative activity with increase in the degree of hydration. The pre-coated immobilized α-amylase showed a higher k/K and lower activation energy compared to the free and uncoated-immobilized preparation, respectively. The results suggest that the immobilization of α-amylase is a potentially useful approach for commercial starch hydrolysis in two-phase systems.

  7. Immobilization of bacterial proteases on water-solved polymer by means of electron beam

    NASA Astrophysics Data System (ADS)

    Gonchar, A. M.; Auslender, V. L.

    1996-12-01

    Possibility of electron beam usage for proteases' immobilization on 1,4-polyalkylene oxide (1,4-PAO) was studied to obtain biologically active complex for multi-purpose usage. It is shown that immobilization of Bacillus Subtilis protease takes place due to free-radical linking of enzyme and carrier with formation of mycellium-like structures. Immobilization improves heat resistance of enzyme up to 60°C without substrate and up to 80°C in presence of substrate, widens range of pH activity in comparison with non-immobilized forms. Immobilized proteases do not contain peroxides or long-live radicals. Our results permitted to create technologies for production of medical and veterinary preparations, active components for wool washing agents and leather fabrication technology.

  8. Synthesis, characterization of silica gel phases-chemically immobilized-4-aminoantipyrene and applications in the solid phase extraction, preconcentration and potentiometric studies.

    PubMed

    Osman, Mohamad M; Kholeif, Sherif A; Abou-Almaaty, Nevine A; Mahmoud, Mohamad E

    2004-05-01

    Two new 4-aminoantipyrene chemically-immobilized silica gel phases: ii (N,N-donor) and iii (N,O-donor), were synthesized and characterized by IR and surface coverage determination. The latter was accomplished by thermal desorption and metal probe methods, giving 0.300 and 0.312 mmol g(-1) for ii and 0.220 and 0.250 mmol g(-1) for iii. Moreover, potentiometric titration provided a surface coverage of 0.323 mmol g(-1) for ii. The metal capacity values in mmol g(-1) of ii, iii and the active silica gel phase i for a series of di- and trivalent metal ions were determined at pH 1.0 - 6.7. Phase i showed the lowest values, while ii and iii reflected higher affinity toward most of the metal ions. The highest values were 0.300 for Hg(II)-ii and 0.220 mmol g(-1) for Cd(II)-iii. Distribution coefficients (log Kd) were in the range of 3.57 - 4.76 for ii and 2.32 - 3.46 for iii, thus confirming certain selectivity characters of the solid extractors. The application of the phases as solid extractors and preconcentrators for some heavy metal ions is presented. Good percentage extraction and removal of 94 - 98 +/- 4 - 6% of the spiked 1.000 microg ml(-1) of Hg(II), Cd(II), Pb(II), Cu(II) and Zn(II) and good percentage recovery of 94 - 99 +/- 3 - 6% of 50 ng ml(-1) of these ions from tap water samples were obtained. Stability constants of H(I) and Cu(II) with ii for the two-phase mixture at 25 degrees C and I = 0.1 (KCI) were determined potentiometrically. The pKa of ii are 5.6 and 8.4, while the log K values for CuHL and CuL (L = ii) are 6.3 and 5.8, respectively, leading to the determination of several analytical data for Cu(II)-ii. PMID:15171292

  9. 3D-Printed Small-Animal Immobilizer for Use in Preclinical Radiotherapy

    PubMed Central

    McCarroll, Rachel E; Rubinstein, Ashley E; Kingsley, Charles V; Yang, Jinzhong; Yang, Peiying; Court, Laurence E

    2015-01-01

    We have designed a method for immobilizing the subjects of small-animal studies using a study group–specific 3D-printed immobilizer that significantly reduces interfraction rotational variation. A cone-beam CT scan acquired from a single specimen in a study group was used to create a 3D-printed immobilizer that can be used for all specimens in the same study group. 3D printing allows for the incorporation of study-specific features into the immobilizer design, including geometries suitable for use in MR and CT scanners, holders for fiducial markers, and anesthesia nose cones of various sizes. Using metrics of rotational setup variations, we compared the current setup in our small-animal irradiation system, a half-pipe bed, with the 3D-printed device. We also assessed translational displacement within the immobilizer. The printed design significantly reduced setup variation, with average reductions in rotational displacement of 76% ± 3% (1.57 to 0.37°) in pitch, 78% ± 3% (1.85 to 0.41°) in yaw, and 87% ± 3% (5.39 to 0.70°) in roll. Translational displacement within the printed immobilizer was less than 1.5 ± 0.3 mm. This method of immobilization allows for repeatable setup when using MR or CT scans for the purpose of radiotherapy, streamlines the workflow, and places little burden on the study subjects. PMID:26424253

  10. Technetium Immobilization Forms Literature Survey

    SciTech Connect

    Westsik, Joseph H.; Cantrell, Kirk J.; Serne, R. Jeffrey; Qafoku, Nikolla

    2014-05-01

    Of the many radionuclides and contaminants in the tank wastes stored at the Hanford site, technetium-99 (99Tc) is one of the most challenging to effectively immobilize in a waste form for ultimate disposal. Within the Hanford Tank Waste Treatment and Immobilization Plant (WTP), the Tc will partition between both the high-level waste (HLW) and low-activity waste (LAW) fractions of the tank waste. The HLW fraction will be converted to a glass waste form in the HLW vitrification facility and the LAW fraction will be converted to another glass waste form in the LAW vitrification facility. In both vitrification facilities, the Tc is incorporated into the glass waste form but a significant fraction of the Tc volatilizes at the high glass-melting temperatures and is captured in the off-gas treatment systems at both facilities. The aqueous off-gas condensate solution containing the volatilized Tc is recycled and is added to the LAW glass melter feed. This recycle process is effective in increasing the loading of Tc in the LAW glass but it also disproportionally increases the sulfur and halides in the LAW melter feed which increases both the amount of LAW glass and either the duration of the LAW vitrification mission or the required supplemental LAW treatment capacity.

  11. Surface and Interface Control on Photochemically Initiated Immobilization

    SciTech Connect

    Liu, Li; Engelhard, Mark H.; Yan, Mingdi

    2006-11-01

    Surface and interface properties are important in controlling the yield and efficiency of the photochemically initiated immobilization. Using a silane-functionalized perfluorophenylazide (PFPA-silane) as the photoactive crosslinker, the immobilization of polymers was studied by adjusting the density of the surface azido groups. Dilution of the photolinker resulted in a gradual decrease in the density of surface azido groups as well as the thickness of the immobilized film. When a non-photoactive silane was added to PFPA-silane, the film thickness decreased more rapidly, indicating that the additive competed with PFPA-silane and effectively reduced the density of the surface azido groups. The effect of surface topography was studied by adding a non-photoactive silane with either a shorter (n-propyltrimethoxysilane (PTMS)) or a longer spacer (n-octadecyltrimethoxysilane (ODTMS)). In most cases the long chain ODTMS shielded the surface azido groups resulting in more rapid decrease in film thickness as compared to PTMS treated under the same conditions. As the density of the surface azido groups decreased, the immobilized polymer changed from smooth films to patched structures, and eventually single polymer molecules.

  12. Leukocyte responses to immobilized patterns of CXCL8.

    PubMed

    Girrbach, Maria; Rink, Ina; Ladnorg, Tatjana; Azucena, Carlos; Heißler, Stefan; Haraszti, Tamás; Schepers, Ute; Schmitz, Katja

    2016-06-01

    The attachment of neutrophils to the endothelial surface and their migration towards the site of inflammation following chemokine gradients play an essential role in the innate immune response. Chemokines adhere to glycosaminoglycans on the endothelial surface to be detected by leukocytes and trigger their movement along surface- bound gradients in a process called haptotaxis. In assays to systematically study the response of leukocytes to surface-bound compounds both the spatial arrangement of the compound as well as the mode of immobilization need to be controlled. In this study microcontact printing was employed to create patterns of hydrophobic or functionalized thiols on gold-coated glass slides and CXCL8 was immobilized on the thiol coated areas using three different strategies. Human neutrophils adhered to the CXCL8-coated lines but not to the PEG-coated background. We could show that more cells adhered to CXCL8 adsorbed to hydrophobic octadecanethiol than on CXCL8 covalently bound to amino undecanethiol or CXCL8 specifically bound to immobilized heparin on aminothiol. Likewise general cell activity such as lamellipodia formation and random migration were most pronounced for CXCL8 adsorbed on a hydrophobic surface which may be attributed to the larger amounts of protein immobilized on this type of surface. PMID:26970827

  13. Immobilization of microalgae for biosorption and degradation of butyltin chlorides.

    PubMed

    Zhang, L; Huang, G; Yu, Y

    1998-07-01

    Since the discovery of their biocidal properties in the 1950s, organotin compounds have found a large spectrum of industrial applications such as wood and textile preservatives, fungicides and pesticides, and antifouling paint on ships and fishing equipment. The fate and environmental impact of butyltins have been the subjects of a large body of research in the last decades. Biosorption and degradation of butyltin compounds by immobilized microalgae chlorella were studied in this paper, aiming to find an alternative way to solve organotin pollution problem. Chlorella emersonii cells were entrapped in a calcium aginate matrix. The cell growth rates, respiratory rate and chlorophyll a content were studied and compared. Results showed that immobilized chlorella had increased respiratory and growth rates, and almost equal chlorophyll a content when compared with free cells. Cell leakage was slight during the 20-day experimental period Cell leakage from the matrix was unrelated to cell growth within the matrix. Immobilized chlorella was applied to deal with butytin contaminated aquatic solutions. Immobilized chlorella had increased degradation rates of tri-, di-, and mono-butyltin chlorides in aquatic solutions, and lower biological accumulation factors on cells, than free cells, which indicates a potential use for tackleing organotin polluted water body. PMID:9663338

  14. Plutonium immobilization -- Can loading. Revision 1

    SciTech Connect

    Kriikku, E.

    2000-03-13

    The Savannah River Site (SRS) will immobilize excess plutonium in the proposed Plutonium Immobilization Project (PIP). The PIP adds the excess plutonium to ceramic pucks, loads the pucks into cans, and places the cans into DWPF canisters. This paper discusses the PIP process steps, the can loading conceptual design, can loading equipment design, and can loading work completed.

  15. Tyrosinase immobilized enzyme reactor: development and evaluation.

    PubMed

    de Oliveira, Karina Bora; Mischiatti, Keylla Lençone; Fontana, José Domingos; de Oliveira, Brás Heleno

    2014-01-15

    Immobilized enzyme reactors of tyrosinase (tyr-IMERs) for use on-line in HPLC system were prepared by different procedures and then compared. The enzyme, obtained from Agaricus bisporus, was immobilized on epoxy-silica which was prepared using different conditions. Enzyme immobilization was conducted by both in situ and in batch techniques. The different procedures were compared in terms of protein and activity retention, IMERs activity, kinetics and stability. The influence of immobilization procedure on enzyme activity and the behavior of the IMERs against a standard inhibitor were also investigated. In situ immobilization on epoxy-silica, synthesized using microwave assistance, provided the best conditions to prepare tyrosinase IMERs. The tyr-IMERs were successfully tested with known and potential inhibitors of tyrosinase, and the results showed that they can be used for the screening of inhibitors of that enzyme. PMID:24317418

  16. Immobilization of whole cells using polymeric coatings

    SciTech Connect

    Lawton, C.W.; Klei, H.E.; Sunstrom, D.V.; Voronka, P.J.; Scott, C.D.

    1986-01-01

    A cell immobilization procedure was developed using latex coatings on solid particles. The method's widespread applicability has been demonstrated by successfully immobilizing Saccharomyces cerevisiae (ethanol production), Bacillus subtilis (tryptophan production). Penicillium chrysogenum (penicillin G production), and Escherichia coli (aspartic acid production). In contrast to other immobilization methods, this procedure produces a pellicular particle that is porous, allowing rapid substrate and gas transfer, has a hard core to avoid compression in large beds, and is dense to allow use in fluidized beds. The immobilization procedure was optimized with S. cerevisiae. Kinetic constants obtained were used to calculate effectiveness factors to show that there was minimal intraparticle diffusion resistance. Reactors utilizing the optimized particles were run for 300 hours to evaluate immobilized particle half-life which was 250 hours.

  17. Immobilized fluid membranes for gas separation

    DOEpatents

    Liu, Wei; Canfield, Nathan L; Zhang, Jian; Li, Xiaohong Shari; Zhang, Jiguang

    2014-03-18

    Provided herein are immobilized liquid membranes for gas separation, methods of preparing such membranes and uses thereof. In one example, the immobilized membrane includes a porous metallic host matrix and an immobilized liquid fluid (such as a silicone oil) that is immobilized within one or more pores included within the porous metallic host matrix. The immobilized liquid membrane is capable of selective permeation of one type of molecule (such as oxygen) over another type of molecule (such as water). In some examples, the selective membrane is incorporated into a device to supply oxygen from ambient air to the device for electrochemical reactions, and at the same time, to block water penetration and electrolyte loss from the device.

  18. Immobilized Lactase in the Biochemistry Laboratory

    NASA Astrophysics Data System (ADS)

    Allison, Matthew J.; Bering, C. Larry

    1998-10-01

    Immobilized enzymes have many practical applications. They may be used in clinical, industrial, and biotechnological laboratories and in many clinical diagnostic kits. For educational purposes, use of immobilized enzymes can easily be taught at the undergraduate or even secondary level. We have developed an immobilized enzyme experiment that combines many practical techniques used in the biochemistry laboratory and fits within a three-hour time frame. In this experiment, lactase from over-the-counter tablets for patients with lactose intolerance is immobilized in polyacrylamide, which is then milled into small beads and placed into a chromatography column. A lactose solution is added to the column and the eluant is assayed using the glucose oxidase assay, available as a kit. We have determined the optimal conditions to give the greatest turnover of lactose while allowing the immobilized enzymes to be active for long periods at room temperature.

  19. Spine immobilization: prehospitalization to final destination.

    PubMed

    Kang, Daniel G; Lehman, Ronald A

    2011-01-01

    Care of the combat casualty with spinal column or spinal cord injury has not been previously described, particularly in regards to spinal immobilization. The ultimate goal of spinal immobilization in the combat casualty is to first ``do no further harm'' and then provide a stable, painless spine and an optimal neurologic recovery. The protocol for treatment of the combat casualty with suspected spinal column or spinal cord injury from the battlefield to final arrival at a definitive treatment center is discussed, and the special considerations for medical evacuation off the battlefield and for aeromedical transport are delineated. Selective prehospital spine immobilization, which involves spinal immobilization with backboard, semi-rigid cervical collar, lateral supports, and straps or tape, is recommended if there is suspicion of spinal column or spinal cord injury in the combat casualty and when conditions and resources permit. The authors do not recommend spinal immobilization for the combat casualty with isolated penetrating trauma. PMID:21477526

  20. The effects of joint immobilization on articular cartilage of the knee in previously exercised rats

    PubMed Central

    Maldonado, Diogo Correa; da Silva, Marcelo Cavenaghi Pereira; Neto, Semaan El-Razi; Souza, Mônica Rodrigues; Souza, Romeu Rodrigues

    2013-01-01

    Studies have determined the effects of joint immobilization on the articular cartilage of sedentary animals, but we are not aware of any studies reporting the effects of joint immobilization in previously trained animals. The objective of the present study was to determine whether exercise could prevent degeneration of the articular cartilage that accompanies joint immobilization. We used light microscopy to study the thickness, cell density, nuclear size, and collagen density of articular cartilage of the femoral condyle of Wistar rats subjected to aerobic physical activity on an adapted treadmill five times per week. Four groups of Wistar rats were used: a control group (C), an immobilized group (I), an exercised group (E), and an exercised and then immobilized group (EI). The right knee joints from rats in groups I and EI were immobilized at 90 °C of flexion using a plastic cast for 8 weeks. Cartilage thickness decreased significantly in group I (mean, 120.14 ± 15.6 μm, P < 0.05), but not in group EI (mean, 174 ± 2.25), and increased significantly in group E (mean, 289.49 ± 9.15) compared with group C (mean, 239.20 ± 6.25). The same results were obtained for cell density, nuclear size, and collagen density (in all cases, P < 0.05). We concluded that exercise can prevent degenerative changes in femoral articular cartilage caused by immobilization of the knee joint. PMID:23480127

  1. Cellobiose hydrolysis using Pichia etchellsii cells immobilized in calcium alginate

    SciTech Connect

    Jain, D.; Ghose, T.K.

    1984-04-01

    Cellulose degradation rates can be increased by the hydrolysis of cellobiose using immobilized beta-glucosidase. Production of beta-glucosidase in four yeasts was studied and a maximum activity of 1.22 IU/mg cells was obtained in cells of Pichia etchellsii grown on 3% cellobiose. The immobilization of beta-glucosidase containing cells on various solid supports was studied and entrapment in calcium alginate gel beads was found to be the best method. After ten sequential batch uses of the preparation, 96.5% of the initial activity was retained. The pH and temperature optima for free and immobilized cells were pH 6.5 (0.05M Maleate buffer) and 50/sup 0/C however, the enzyme has a better thermal stability at 45/sup 0/C. Beads stored at 4/sup 0/C for six months retain 80% of their activity. Kinetic studies performed on free and immobilized cells show that glucose is a noncompetitive product inhibitor. The immobilized preparation was limited by pore diffusion but exhibited no film-diffusion resistance during packed bed reactor operation. Good plug flow characteristics were observed. A model for reaction with pore diffusion for a noncompetitive type of inhibited system was developed and applied to this system. The reation rate with diffusional limitations was determined by using the model and effectiveness factors were calculated for different particle sizes. The modified rate expression using the effectiveness factor represented batch and packed bed reactor operation satisfactorily. The productivity in the packed bed column fell rapidly with an increase in conversion rate indicating that the operating conditions of the column would have to balance high conversion rates with acceptable productivity. The half-life in the column was affected by temperature, increasing to over seventeen days at 40/sup 0/C and decreasing to less than two days at 50/sup 0/C.

  2. Stability of immobilized yeast alcohol dehydrogenase

    SciTech Connect

    Ooshima, H.; Genko, Y.; Harano, Y.

    1981-12-01

    The effects of substrate on stabilities of native (NA) and three kinds of immobilized yeast alcohol dehydrogenase (IMA), namely PGA (the carrier; porous glass), SEA (agarose gel) prepared covalently, and AMA (anion-exchange resin) prepared ionically, were studied. The following results were obtained. 1) The deactivations of NA and IMA free from the substrate or in the presence of ethanol obey the first-order kinetics, whereas, in the presence of butyraldehyde, their deactivation behaviors are explained on the basis of coexistence of two components of YADHs, namely the labile E1 and the comparatively stable E2, with different first-order deactivation constants. (2) A few attempts for stabilization of IMA were carried out from the viewpoint of the effects of crosslinkages among the subunits of YADH for PGA and the multibonding between the carrier and enzyme for SEA. The former is effective for the stabilization, whereas the latter is not. (Refs. 19).

  3. Arthrobacter sp. lipase immobilization for improvement in stability and enantioselectivity.

    PubMed

    Chaubey, Asha; Parshad, Rajinder; Koul, Surrinder; Taneja, Subhash C; Qazi, Ghulam N

    2006-12-01

    Arthrobacter sp. lipase (ABL, MTCC no. 5125) is being recognized as an efficient enzyme for the resolution of drugs and their intermediates. The immobilization of ABL on various matrices for its enantioselectivity, stability, and reusability has been studied. Immobilization by covalent bonding on sepharose and silica afforded a maximum of 380 and 40 IU/g activity, respectively, whereas sol-gel entrapment provided a maximum of 150 IU/g activity in dry powder. The immobilized enzyme displayed excellent stability in the pH range of 4-10 and even at higher temperature, i.e., 50-60 degrees C, compared to free enzyme, which is unstable under extreme conditions. The resolution of racemic auxiliaries like 1-phenyl ethanol and an intermediate of antidepressant drug fluoxetine, i.e., ethyl 3-hydroxy-3-phenylpropanoate alkyl acylates, provided exclusively R-(+) products ( approximately 99% ee, E=646 and 473), compared to cell free extract/whole cells which gave a product with approximately 96% ee (E=106 and 150). The repeated use (ten times) of covalently immobilized and entrapped ABL resulted in no loss in activity, thus demonstrating its prospects for commercial applications. PMID:16896604

  4. Papain immobilized polyurethane as an ureteral stent material.

    PubMed

    Maria Manohar, Cynthya; Doble, Mukesh

    2016-05-01

    Long term use of polyurethane-based ureteral stent is hampered by the development of infection due to the formation of bacterial biofilm and salt deposition. Here papain, is covalently immobilized to polyurethane using glutarldehyde and is investigated as a possible anti-infective ureteral stent material. Fourier transform infrared spectrum confirmed its immobilization. Immobilized enzyme retained 85% of the activity of the free enzyme and about 12% loss of enzyme was observed from the polymer surface in one month. The modified polyurethane showed 8 log reduction in Staphylococcus aureus and 7 log reduction in Escherichia coli live colonies and 3-4 times decrease in the protein and carbohydrate in the biofilms than bare polymer. The amount of calcium and magnesium salts deposited on the polymer surface reduced by 40% after enzyme immobilization. 80% of L6 myoblast cells were viable on this material which indicated that it was noncytotoxic. A linear regression equation with hydrophilicity of the polymer surface and the cell surface hydrophobicity as the two independent variables was able to predict the number of live cells attached on the modified PU. This study indicated the possibility of using such an approach to overcome the problems of ureteral stent associated biofilm and salt encrustation. PMID:26853541

  5. LPS interactions with immobilized and soluble antimicrobial peptides.

    PubMed

    Gustafsson, Anna; Olin, Anders I; Ljunggren, Lennart

    2010-04-19

    A promising approach in sepsis therapy is the use of peptides truncated from serum- and membrane-proteins with binding domains for LPS: antimicrobial peptides (AMPs). AMPs can be useful in combination with conventional antibiotics to increase killing and neutralize LPS. Although many AMPs show a high specificity towards bacterial membranes, they can also exhibit toxicity, i.e. non-specific membrane lysis, of mammalian cells such as erythrocytes and therefore, unsuitable as systemic drugs. A way to overcome this problem may be an extracorporeal therapy with immobilized peptides. This study will compare neutralization of LPS using different AMPs in solution and when immobilized on to solid phases. The peptides ability to neutralize LPS-induced cytokine release in whole blood will also be tested. The peptides are truncated derivates from the known AMPs LL-37, SC4, BPI, S3 Delta and CEME. Two different methods were used to immobilize peptides, biomolecular interaction analysis, and Pierce SulfoLink Coupling Gel. To investigate LPS binding in solution the LAL test was used. After whole blood incubation with LPS and AMPs ELISA was used to measure TNFalpha, IL-1 beta and IL-6 production. The results suggest that immobilization of antimicrobial peptides does not inhibit their capacity to neutralize LPS, although there are differences between the peptides tested. Thus, peptides derived from LL-37 and CEME were more efficient both in LPS binding and neutralizing LPS-induced cytokine production. PMID:20233038

  6. Bioflavour production from orange peel hydrolysate using immobilized Saccharomyces cerevisiae.

    PubMed

    Lalou, Sofia; Mantzouridou, Fani; Paraskevopoulou, Adamantini; Bugarski, Branko; Levic, Steva; Nedovic, Victor

    2013-11-01

    The rising trend of bioflavour synthesis by microorganisms is hindered by the high manufacturing costs, partially attributed to the cost of the starting material. To overcome this limitation, in the present study, dilute-acid hydrolysate of orange peel was employed as a low-cost, rich in fermentable sugars substrate for the production of flavour-active compounds by Saccharomyces cerevisiae. With this purpose, the use of immobilized cell technology to protect cells against the various inhibitory compounds present in the hydrolysate was evaluated with regard to yeast viability, carbon and nitrogen consumption and cell ability to produce flavour active compounds. For cell immobilization the encapsulation in Ca alginate beads was used. The results were compared with those obtained using free-cell system. Based on the data obtained immobilized cells showed better growth performance and increased ability for de novo synthesis of volatile esters of "fruity" aroma (phenylethyl acetate, ethyl hexanoate, octanoate, decanoate and dodecanoate) than those of free cells. The potential for in situ production of new formulations containing flavour-active compounds derive from yeast cells and also from essential oil of orange peel (limonene, α-terpineol) was demonstrated by the fact that bioflavour mixture was found to accumulate within the beads. Furthermore, the ability of the immobilized yeast to perform efficiently repeated batch fermentations of orange peel hydrolysate for bioflavour production was successfully maintained after six consecutive cycles of a total period of 240 h. PMID:23995224

  7. Activation of immobilized enzymes by acoustic wave resonance oscillation.

    PubMed

    Nishiyama, Hiroshi; Watanabe, Tomoya; Inoue, Yasunobu

    2014-12-01

    Acoustic wave resonance oscillation has been used successfully in the development of methods to activate immobilized enzyme catalysts. In this study, resonance oscillation effects were demonstrated for enzyme reactions on galactose oxidase (GAD), D-amino acid oxidase (DAAO), and L-amino acid oxidase (LAAO), all of which were immobilized covalently on a ferroelectric lead zirconate titanate (PZT) device that could generate thickness-extensional resonance oscillations (TERO) of acoustic waves. For galactose oxidation on immobilized GAD in a microreactor, TERO generation immediately increased enzyme activity 2- to 3-fold. Eliminating TERO caused a slight decrease in the activity, with ∼90% of the enhanced activity retained while the reaction proceeded. Contact of the enhanced enzyme with a galactose-free solution caused almost complete reversion of the activity to the original low level before TERO generation, indicating that, not only TERO-induced GAD activation, but also preservation of the increased activity, required a galactose substrate. Similar activity changes with TERO were observed for enzyme reactions on DAAO and LAAO. Kinetic analysis demonstrated that TERO helped strengthen the interactions of the immobilized enzyme with the reactant substrate and promoted formation of an activation complex. PMID:25442945

  8. On-chip immobilization of planarians for in vivo imaging

    PubMed Central

    Dexter, Joseph P.; Tamme, Mary B.; Lind, Christine H.; Collins, Eva-Maria S.

    2014-01-01

    Planarians are an important model organism for regeneration and stem cell research. A complete understanding of stem cell and regeneration dynamics in these animals requires time-lapse imaging in vivo, which has been difficult to achieve due to a lack of tissue-specific markers and the strong negative phototaxis of planarians. We have developed the Planarian Immobilization Chip (PIC) for rapid, stable immobilization of planarians for in vivo imaging without injury or biochemical alteration. The chip is easy and inexpensive to fabricate, and worms can be mounted for and removed after imaging within minutes. We show that the PIC enables significantly higher-stability immobilization than can be achieved with standard techniques, allowing for imaging of planarians at sub-cellular resolution in vivo using brightfield and fluorescence microscopy. We validate the performance of the PIC by performing time-lapse imaging of planarian wound closure and sequential imaging over days of head regeneration. We further show that the device can be used to immobilize Hydra, another photophobic regenerative model organism. The simple fabrication, low cost, ease of use, and enhanced specimen stability of the PIC should enable its broad application to in vivo studies of stem cell and regeneration dynamics in planarians and Hydra. PMID:25227263

  9. Ceramic Hosts for Fission Products Immobilization

    SciTech Connect

    Peter C Kong

    2010-07-01

    metal ions, Mg and Ca, in the ceramic host phases. The immobilization of rear earth (lanthanide series) fission products in these ceramic host phases will also be studied this year. Cerium oxide is chosen to represent the rear earth fission product for substitution studies in spinel, perovskite and zirconolite ceramic hosts. Cerium has +3 and +4 oxidation states and it can replace some of the trivalent or tetravalent host ions to produce the substitution ceramics such as MgAl2-xCexO4, CaTi1-xCexO3, CaZr1-xCexTi2O7 and CaZrTi2-xCexO7. X-ray diffraction analysis will be used to compare the crystalline structures of the pure ceramic hosts and the substitution phases. SEM-EDX analysis will be used to study the Ce distribution in the ceramic host phases. The range of cerium doping is planned to reach the full substitution of the trivalent or tetravalent ions, Al, Ti and Zr, in the ceramic host phases.

  10. Immobilized humic substances on an anion exchange resin and their role on the redox biotransformation of contaminants.

    PubMed

    Cervantes, Francisco J; Gonzalez-Estrella, Jorge; Márquez, Arturo; Alvarez, Luis H; Arriaga, Sonia

    2011-01-01

    A novel technique to immobilize humic substances (HS) on an anion exchange resin is presented. Immobilized HS were demonstrated as an effective solid-phase redox mediator (RM) during the reductive biotransformation of carbon tetrachloride (CT) and the azo model compound, Reactive Red 2 (RR2). Immobilized HS increased ∼4-fold the extent of CT reduction to chloroform by a humus-reducing consortium in comparison to incubations lacking HS. Immobilized HS also increased 2-fold the second-order rate constant of decolorization of RR2 as compared with sludge incubations lacking HS. To our knowledge, the present study constitutes the first demonstration of immobilized HS serving as an effective solid-phase RM during the reductive biotransformation of priority contaminants. The immobilizing technique developed could be appropriate for enhancing the redox biotransformation of recalcitrant pollutants in anaerobic wastewater treatment systems. PMID:20801024

  11. Enzymatic degradation of aromatic hydrocarbon intermediates using a recombinant dioxygenase immobilized onto surfactant-activated carbon nanotube.

    PubMed

    Suma, Yanasinee; Lim, Heejun; Kwean, Oh Sung; Cho, Suyeon; Yang, Junwon; Kim, Yohan; Kang, Christina S; Kim, Han S

    2016-06-01

    This study examined the enzymatic decomposition of aromatic hydrocarbon intermediates (catechol, 4-chlorocatechol, and 3-methylcatechol) using a dioxygenase immobilized onto single-walled carbon nanotube (SWCNT). The surfaces of SWCNTs were activated with surfactants. The dioxygenase was obtained by recombinant technique: the corresponding gene was cloned from Arthrobacter chlorophenolicus A6, and the enzyme was overexpressed and purified subsequently. The enzyme immobilization yield was 62%, and the high level of enzyme activity was preserved (60-79%) after enzyme immobilization. Kinetic analyses showed that the substrate utilization rates and the catalytic efficiencies of the immobilized enzyme for all substrates (target aromatic hydrocarbon intermediates) tested were similar to those of the free enzyme, indicating that the loss of enzyme activity was minimal during enzyme immobilization. The immobilized enzyme was more stable than the free enzyme against abrupt changes in pH, temperature, and ionic strength. Moreover, it retained high enzyme activity even after repetitive use. PMID:26810145

  12. Plutonium Immobilization Can Loading Concepts

    SciTech Connect

    Kriikku, E.; Ward, C.; Stokes, M.; Randall, B.; Steed, J.; Jones, R.; Hamilton, L.; Rogers, L.; Fiscus, J.; Dyches, G.

    1998-05-01

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses five can loading conceptual designs and the lists the advantages and disadvantages for each concept. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas. The can loading welder and cutter are very similar to the existing Savannah River Site (SRS) FB-Line bagless transfer welder and cutter and thus they are a low priority development item.

  13. Immobilization of organic liquid wastes

    SciTech Connect

    Greenhalgh, W.O.

    1985-08-07

    This report describes a portland cement immobilization process for the disposal treatment of radioactive organic liquid wastes which would be generated in a a FFTF fuels reprocessing line. An incineration system already on-hand was determined to be too costly to operate for the 100 to 400 gallons per year organic liquid. Organic test liquids were dispersed into an aqueous phosphate liquid using an emulsifier. A total of 109 gallons of potential and radioactive aqueous immiscible organic liquid wastes from Hanford 300 Area operations were solidified with portland cement and disposed of as solid waste during a 3-month test program with in-drum mixers. Waste packing efficiencies varied from 32 to 40% and included pump oils, mineral spirits, and TBP-NPH type solvents.

  14. Plutonium Immobilization Project Baseline Formulation

    SciTech Connect

    Ebbinghaus, B.

    1999-02-01

    A key milestone for the Immobilization Project (AOP Milestone 3.2a) in Fiscal Year 1998 (FY98) is the definition of the baseline composition or formulation for the plutonium ceramic form. The baseline formulation for the plutonium ceramic product must be finalized before the repository- and plant-related process specifications can be determined. The baseline formulation that is currently specified is given in Table 1.1. In addition to the baseline formulation specification, this report provides specifications for two alternative formulations, related compositional specifications (e.g., precursor compositions and mixing recipes), and other preliminary form and process specifications that are linked to the baseline formulation. The preliminary specifications, when finalized, are not expected to vary tremendously from the preliminary values given.

  15. Recovery time course in contractile function of fast and slow skeletal muscle after hindlimb immobilization

    NASA Technical Reports Server (NTRS)

    Witzmann, F. A.; Kim, D. H.; Fitts, R. H.

    1982-01-01

    The present study was undertaken to characterize the time course and extent of recovery in the isometric and isotonic contractile properties of fast and slow skeletal muscle following 6 wk of hindlimb immobilization. Female Sprague-Dawley rats were randomly assigned to an immobilized group or a control group. The results of the study show that fast and slow skeletal muscles possess the ability to completely recover normal contractile function following 6 wk of hindlimb immobilization. The rate of recovery is dependent on the fiber type composition of the affected muscle.

  16. Application of granular activated carbon/MnFe2O4 composite immobilized on C. glutamicum MTCC 2745 to remove As(III) and As(V): Kinetic, mechanistic and thermodynamic studies

    NASA Astrophysics Data System (ADS)

    Podder, M. S.; Majumder, C. B.

    2016-01-01

    The main objective of the present study was to investigate the efficiency of Corynebacterium glutamicum MTCC 2745 immobilized on granular activated carbon/MnFe2O4 (GAC/MnFe2O4) composite to treat high concentration of arsenic bearing wastewater. Non-linear regression analysis was done for determining the best-fit kinetic model on the basis of three correlation coefficients and three error functions and also for predicting the parameters involved in kinetic models. The results showed that Fractal-like mixed 1,2 order model for As(III) and Brouser-Weron-Sototlongo as well as Fractal-like pseudo second order models for As(V) were proficient to provide realistic description of biosorption/bioaccumulation kinetic. Applicability of mechanistic models in the current study exhibited that the rate governing step in biosorption/bioaccumulation of both As(III) and As(V) was film diffusion rather than intraparticle diffusion. The evaluated thermodynamic parameters ΔG0, ΔH0 and ΔS0 revealed that biosorption/bioaccumulation of both As(III) and As(V) was feasible, spontaneous and exothermic under studied conditions.

  17. Application of granular activated carbon/MnFe₂O₄ composite immobilized on C. glutamicum MTCC 2745 to remove As(III) and As(V): Kinetic, mechanistic and thermodynamic studies.

    PubMed

    Podder, M S; Majumder, C B

    2016-01-15

    The main objective of the present study was to investigate the efficiency of Corynebacterium glutamicum MTCC 2745 immobilized on granular activated carbon/MnFe2O4 (GAC/MnFe2O4) composite to treat high concentration of arsenic bearing wastewater. Non-linear regression analysis was done for determining the best-fit kinetic model on the basis of three correlation coefficients and three error functions and also for predicting the parameters involved in kinetic models. The results showed that Fractal-like mixed 1,2 order model for As(III) and Brouser-Weron-Sototlongo as well as Fractal-like pseudo second order models for As(V) were proficient to provide realistic description of biosorption/bioaccumulation kinetic. Applicability of mechanistic models in the current study exhibited that the rate governing step in biosorption/bioaccumulation of both As(III) and As(V) was film diffusion rather than intraparticle diffusion. The evaluated thermodynamic parameters ΔG(0), ΔH(0) and ΔS(0) revealed that biosorption/bioaccumulation of both As(III) and As(V) was feasible, spontaneous and exothermic under studied conditions. PMID:26322840

  18. Antimicrobial Properties of Lysosomal Enzymes Immobilized on NH₂Functionalized Silica-Encapsulated Magnetite Nanoparticles.

    PubMed

    Bang, Seung Hyuck; Sekhon, Simranjeet Singh; Cho, Sung-Jin; Kim, So Jeong; Le, Thai-Hoang; Kim, Pil; Ahn, Ji-Young; Kim, Yang-Hoon; Min, Jiho

    2016-01-01

    The immobilization efficiency, antimicrobial activity and recovery of lysosomal enzymes on NH2 functionalized magnetite nanoparticles have been studied under various conditions. The immobi- lization efficiency depends upon the ratio of the amount of enzyme and magnetite and it shows an increase with magnetite concentration which is due to the presence of amine group at the magnetite surface that leads to a strong attraction. The optimized reaction time to immobilize the lysosomal enzymes on magnetite was determined by using a rolling method. The immobilization efficiency increases with reaction time and reached a plateau after 5 minutes and then remained constant for 10 minutes. However, after 30 minutes the immobilization efficiency decreased to 85%, which is due to the weaker electrostatic interactions between magnetite and detached lysosomal enzymes. The recovery and stability of immobilized lysosomal enzymes has also been studied. The antimicrobial activity was almost 100% but it decreased upon reuse and no activity was observed after its reuse for seven times. The storage stability of lysosomal enzymes as an antimicrobial agent was about 88%, which decreased to 53% after one day and all activity of immobilized lysosomal enzymes was maintained after five days. Thus, the lysosomal enzymes immobilized on magnetite nanoparticles could potentially be used as antimicrobial agents to remove bacteria. PMID:27398573

  19. Effect of sulfonylureas administered centrally on the blood glucose level in immobilization stress model.

    PubMed

    Sharma, Naveen; Sim, Yun-Beom; Park, Soo-Hyun; Lim, Su-Min; Kim, Sung-Su; Jung, Jun-Sub; Hong, Jae-Seung; Suh, Hong-Won

    2015-05-01

    Sulfonylureas are widely used as an antidiabetic drug. In the present study, the effects of sulfonylurea administered supraspinally on immobilization stress-induced blood glucose level were studied in ICR mice. Mice were once enforced into immobilization stress for 30 min and returned to the cage. The blood glucose level was measured 30, 60, and 120 min after immobilization stress initiation. We found that intracerebroventricular (i.c.v.) injection with 30 µg of glyburide, glipizide, glimepiride or tolazamide attenuated the increased blood glucose level induced by immobilization stress. Immobilization stress causes an elevation of the blood corticosterone and insulin levels. Sulfonylureas pretreated i.c.v. caused a further elevation of the blood corticosterone level when mice were forced into the stress. In addition, sulfonylureas pretreated i.c.v. alone caused an elevation of the plasma insulin level. Furthermore, immobilization stress-induced insulin level was reduced by i.c.v. pretreated sulfonylureas. Our results suggest that lowering effect of sulfonylureas administered supraspinally against immobilization stress-induced increase of the blood glucose level appears to be primarily mediated via elevation of the plasma insulin level. PMID:25954123

  20. Preparation and characterization of a thermostable enzyme (Mn-SOD) immobilized on supermagnetic nanoparticles.

    PubMed

    Song, Chongfu; Sheng, Liangquan; Zhang, Xiaobo

    2012-10-01

    Superoxide dismutase (SOD) has been widely applied in medical treatments, cosmetic, food, agriculture, and chemical industries. In industry, the immobilization of enzymes can offer better stability, feasible continuous operations, easy separation and reusing, and significant decrease of the operation costs. However, little attention has focused on the immobilization of the SOD, as well as the immobilization of thermostable enzymes. In this study, the recombinant thermostable manganese superoxide dismutase (Mn-SOD) of Thermus thermophilus wl was purified and covalently immobilized onto supermagnetic 3-APTES-modified Fe(3)O(4)@SiO(2) nanoparticles using glutaraldehyde method to prepare the Mn-SOD bound magnetic nanoparticles. The Mn-SOD nanoparticles were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, X-ray diffraction, transmission electron microscopy, and vibrating sample magnetometer analysis. The results indicated that the diameter of Mn-SOD nanoparticles was 40 (± 5) nm, and its saturation magnetization value was 27.9 emu/g without remanence or coercivity. By comparison with the free Mn-SOD, it was found that the immobilized Mn-SOD on nanoparticles exhibited better resistance to temperature, pH, metal ions, enzyme inhibitors, and detergents. The results showed that the immobilized Mn-SOD on nanoparticles could be reused ten times without significant decrease of enzymatic activity. Therefore, our study presented a novel strategy for the immobilization of thermostable Mn-SOD and for the application of thermostable enzymes. PMID:22237672

  1. Antimicrobial potential of immobilized Lactococcus lactis subsp. lactis ATCC 11454 against selected bacteria.

    PubMed

    Millette, M; Smoragiewicz, W; Lacroix, M

    2004-06-01

    Immobilization of living cells of lactic acid bacteria could be an alternative or complementary method of immobilizing organic acids and bacteriocins and inhibit undesirable bacteria in foods. This study evaluated the inhibition potential of immobilized Lactococcus lactis subsp. lactis ATCC 11454 on selected bacteria by a modified method of the agar spot test. L. lactis was immobilized in calcium alginate (1 to 2%)-whey protein concentrate (0 and 1%) beads. The antimicrobial potential of immobilized L. lactis was evaluated in microbiological media against pathogenic bacteria (Escherichia coli, Salmonella, and Staphylococcus aureus) or Pseudomonas putida, a natural meat contaminant, and against seven gram-positive bacteria used as indicator strains. Results obtained in this study indicated that immobilized L. lactis inhibited the growth of S. aureus, Enterococcus faecalis, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus sakei, Kocuria varians, and Pediococcus acidilactici. Only 4 h of incubation at 35 degrees C resulted in a clear inhibition zone around the beads that increased with time. With the addition of 10 mM of a chelating agent (EDTA) to the media, results showed growth inhibition of E. coli; however, P. putida and Salmonella Typhi were unaffected by this treatment. These results indicate that immobilized lactic acid bacteria strains can be successfully used to produce nisin and inhibit bacterial growth in semisolid synthetic media. PMID:15222547

  2. Effective Immobilization of Agrobacterium sp. IFO 13140 Cells in Loofa Sponge for Curdlan Biosynthesis.

    PubMed

    Martinez, Camila Ortiz; Ruiz, Suelen Pereira; Nogueira, Marcela Tiemi; Bona, Evandro; Portilho, Márcia; Matioli, Graciette

    2015-01-01

    Curdlan production by Agrobacterium sp. IFO13140 immobilized on loofa sponge, alginate and loofa sponge with alginate was investigated. There was no statistically-significant difference in curdlan production when the microorganism was immobilized in different matrices. The loofa sponge was chosen because of its practical application and economy and because it provides a high stability through its continued use. The best conditions for immobilization on loofa sponge were 50 mg of cell, 200 rpm and 72 h of incubation, which provided a curdlan production 1.50-times higher than that obtained by free cells. The higher volumetric productivity was achieved by immobilized cells (0.09 g/L/h) at 150 rpm. The operating stability was evaluated, and until the fourth cycle, immobilized cells retained 87.40% of the production of the first cycle. The immobilized cells remained active after 300 days of storage at 4 °C. The results of this study demonstrate success in immobilizing cells for curdlan biosynthesis, making the process potentially suitable for industrial scale-up. Additional studies may show a possible contribution to the reduction of operating costs. PMID:25946555

  3. Activity of laccase immobilized on TiO2-montmorillonite complexes.

    PubMed

    Wang, Qingqing; Peng, Lin; Li, Guohui; Zhang, Ping; Li, Dawei; Huang, Fenglin; Wei, Qufu

    2013-01-01

    The TiO2-montmorillonite (TiO2-MMT) complex was prepared by blending TiO2 sol and MMT with certain ratio, and its properties as an enzyme immobilization support were investigated. The pristine MMT and TiO2-MMT calcined at 800 °C (TiO2-MMT800) were used for comparison to better understand the immobilization mechanism. The structures of the pristine MMT, TiO2-MMT, and TiO2-MMT800 were examined by HR-TEM, XRD and BET. SEM was employed to study different morphologies before and after laccase immobilization. Activity and kinetic parameters of the immobilized laccase were also determined. It was found that the TiO2 nanoparticles were successfully introduced into the MMT layer structure, and this intercalation enlarged the "d value" of two adjacent MMT layers and increased the surface area, while the calcination process led to a complete collapse of the MMT layers. SEM results showed that the clays were well coated with adsorbed enzymes. The study of laccase activity revealed that the optimum pH and temperature were pH = 3 and 60 °C, respectively. In addition, the storage stability for the immobilized laccase was satisfactory. The kinetic properties indicated that laccase immobilized on TiO2-MMT complexes had a good affinity to the substrate. It has been proved that TiO2-MMT complex is a good candidate for enzyme immobilization. PMID:23771020

  4. Activity of Laccase Immobilized on TiO2-Montmorillonite Complexes

    PubMed Central

    Wang, Qingqing; Peng, Lin; Li, Guohui; Zhang, Ping; Li, Dawei; Huang, Fenglin; Wei, Qufu

    2013-01-01

    The TiO2-montmorillonite (TiO2-MMT) complex was prepared by blending TiO2 sol and MMT with certain ratio, and its properties as an enzyme immobilization support were investigated. The pristine MMT and TiO2-MMT calcined at 800 °C (TiO2-MMT800) were used for comparison to better understand the immobilization mechanism. The structures of the pristine MMT, TiO2-MMT, and TiO2-MMT800 were examined by HR-TEM, XRD and BET. SEM was employed to study different morphologies before and after laccase immobilization. Activity and kinetic parameters of the immobilized laccase were also determined. It was found that the TiO2 nanoparticles were successfully introduced into the MMT layer structure, and this intercalation enlarged the “d value” of two adjacent MMT layers and increased the surface area, while the calcination process led to a complete collapse of the MMT layers. SEM results showed that the clays were well coated with adsorbed enzymes. The study of laccase activity revealed that the optimum pH and temperature were pH = 3 and 60 °C, respectively. In addition, the storage stability for the immobilized laccase was satisfactory. The kinetic properties indicated that laccase immobilized on TiO2-MMT complexes had a good affinity to the substrate. It has been proved that TiO2-MMT complex is a good candidate for enzyme immobilization. PMID:23771020

  5. Thermostable α-amylase immobilization: Enhanced stability and performance for starch biocatalysis.

    PubMed

    Kumar, Gudi Satheesh; Rather, Gulam Mohmad; Gurramkonda, Chandrasekhar; Reddy, Bontha Rajasekhar

    2016-01-01

    The uses of thermostable starch hydrolytic biocatalysts are steadily increasing for the industrial application because of their obvious need for biocatalytic performance at elevated temperatures. The starch liquefaction and saccharification can be carried out simultaneously by the use of thermostable starch hydrolytic biocatalysts, thus minimizing the unit operations, time, and efforts. The cost factor hampers the industrialization of expensive soluble (free) enzymes for biocatalytic applications and the immobilization of enzymes offers promising alternative to the hurdle. The present investigation was aimed for immobilization of thermostable α-amylase using calcium alginate, and statistical optimization studies were carried out for enhanced biocatalytic performance. Initially, one-parameter at a time optimization studies were carried out for identification of significant factors influencing the immobilization. Furthermore, a statistical approach, response surface methodology, was applied for immobilization of α-amylase. The immobilized α-amylase in alginate microbeads showed enhanced stability to temperature and reusable property for up to seven cycles (with the retention of 50% initial activity). Finally, the kinetic behavior of free and immobilized enzyme showed the Km value of 1.2% and 2.6% (w/v) and Vmax of 1,020 and 1,030 U, respectively. Fifty percent reduction in affinity of the immobilized enzyme toward substrate was compensated by its longer stability. PMID:25604037

  6. Metabolic Responses of Bacterial Cells to Immobilization.

    PubMed

    Żur, Joanna; Wojcieszyńska, Danuta; Guzik, Urszula

    2016-01-01

    In recent years immobilized cells have commonly been used for various biotechnological applications, e.g., antibiotic production, soil bioremediation, biodegradation and biotransformation of xenobiotics in wastewater treatment plants. Although the literature data on the physiological changes and behaviour of cells in the immobilized state remain fragmentary, it is well documented that in natural settings microorganisms are mainly found in association with surfaces, which results in biofilm formation. Biofilms are characterized by genetic and physiological heterogeneity and the occurrence of altered microenvironments within the matrix. Microbial cells in communities display a variety of metabolic differences as compared to their free-living counterparts. Immobilization of bacteria can occur either as a natural phenomenon or as an artificial process. The majority of changes observed in immobilized cells result from protection provided by the supports. Knowledge about the main physiological responses occurring in immobilized cells may contribute to improving the efficiency of immobilization techniques. This paper reviews the main metabolic changes exhibited by immobilized bacterial cells, including growth rate, biodegradation capabilities, biocatalytic efficiency and plasmid stability. PMID:27455220

  7. Immobilization depresses insulin signaling in skeletal muscle.

    PubMed

    Hirose, M; Kaneki, M; Sugita, H; Yasuhara, S; Martyn, J A

    2000-12-01

    Prolonged immobilization depresses insulin-induced glucose transport in skeletal muscle and leads to a catabolic state in the affected areas, with resultant muscle wasting. To elucidate the altered intracellular mechanisms involved in the insulin resistance, we examined insulin-stimulated tyrosine phosphorylation of the insulin receptor beta-subunit (IR-beta) and insulin receptor substrate (IRS)-1 and activation of its further downstream molecule, phosphatidylinositol 3-kinase (PI 3-K), after unilateral hindlimb immobilization in the rat. The contralateral hindlimb served as control. After 7 days of immobilization of the rat, insulin was injected into the portal vein, and tibialis anterior muscles on both sides were extracted. Immobilization reduced insulin-stimulated tyrosine phosphorylation of IR-beta and IRS-1. Insulin-stimulated binding of IRS-1 to p85, the regulatory subunit of PI 3-K, and IRS-1-associated PI 3-K activity were also decreased in the immobilized hindlimb. Although IR-beta and p85 protein levels were unchanged, IRS-1 protein expression was downregulated by immobilization. Thus prolonged immobilization may cause depression of insulin-stimulated glucose transport in skeletal muscle by altering insulin action at multiple points, including the tyrosine phosphorylation, protein expression, and activation of essential components of insulin signaling pathways. PMID:11093909

  8. Immobilization and characterization of hemoglobin on modified sporopollenin surfaces.

    PubMed

    Gubbuk, Ilkay Hilal; Ozmen, Mustafa; Maltas, Esra

    2012-06-01

    Hemoglobin was covalently immobilized onto modified sporopollenin surface with different functional groups by chemical reactions to enhance binding ability of protein. In this study, the influence of various silane linker molecules on the capacity of protein binding was studied. For this purpose, activated sporopollenin was modified by 3-aminopropyltriethoxysilane (APTS), 3-chloropropyltrimethoxysilane (CPTS) and (3-glycidyloxypropyl)trimethoxysilane (GPTS). Hemoglobin (Hb) was immobilized on modified sporopollenin surfaces in phosphate buffer saline solution (PBS, pH 7.4) at 4°C. Results showed that GPTS modified sporopollenin surfaces resulted in the highest binding capacity for Hb. Micro porosity of samples was observed through scanning electron microscopy (SEM) and thermal behavior of the samples were studied with thermogravimetric analysis (TGA) within a temperature range: 25-900°C. TGA studies demonstrated the advantages of silane modification for high temperature applications and illustrated differences of the structures due to the different tail groups. PMID:22537474

  9. Plutonium immobilization feed batching system concept report

    SciTech Connect

    Erickson, S.

    2000-07-19

    The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with high level waste glass for permanent storage. Feed batching is one of the first process steps involved with first stage plutonium immobilization. It will blend plutonium oxide powder before it is combined with other materials to make pucks. This report discusses the Plutonium Immobilization feed batching process preliminary concept, batch splitting concepts, and includes a process block diagram, concept descriptions, a preliminary equipment list, and feed batching development areas.

  10. Immobilized Enzymes and Cells as Practical Catalysts

    NASA Astrophysics Data System (ADS)

    Klibanov, Alexander M.

    1983-02-01

    Performance of enzymes and whole cells in commercial applications can often be dramatically improved by immobilization of the biocatalysts, for instance, by their covalent attachment to or adsorption on solid supports, entrapment in polymeric gels, encapsulation, and cross-linking. The effect of immobilization on enzymatic properties and stability of biocatalysts is considered. Applications of immobilized enzymes and cells in the chemical, pharmaceutical, and food industries, in clinical and chemical analyses, and in medicine, as well as probable future trends in enzyme technology are discussed.

  11. Immobilized enzymes and cells as practical catalysts

    SciTech Connect

    Klibanov, A.M.

    1983-02-11

    Performance of enzymes and whole cells in commercial applications can often be dramatically improved by immobilization of the biocatalysts, for instance, by their covalent attachment to or adsorption on solid supports, entrapment in polymeric gels, encapsulation, and cross-linking. The effect of immobilization on enzymatic properties and stability of biocatalysts is considered. Applications of immobilized enzymes and cells in the chemical, pharmaceutical, and food industries, in clinical and chemical analyses, and in medicine, as well as probable future trends in enzyme technology are discussed.

  12. Experimental joint immobilization in guinea pigs. Effects on the knee joint

    NASA Technical Reports Server (NTRS)

    Marcondesdesouza, J. P.; Machado, F. F.; Sesso, A.; Valeri, V.

    1980-01-01

    In young and adult guinea pigs, the aftermath experimentally induced by the immobilization of the knee joint in hyperextended forced position was studied. Joint immobilization which varied from one to nine weeks was attained by plaster. Eighty knee joints were examined macro and microscopically. Findings included: (1) muscular hypotrophy and joint stiffness in all animals, directly proportional to the length of immobilization; (2) haemoarthrosis in the first week; (3) intra-articular fibrous tissue proliferation ending up with fibrous ankylosis; (4) hyaline articular cartilage erosions; (5) various degrees of destructive menisci changes. A tentative explanation of the fibrous tissue proliferation and of the cartilage changes is offered.

  13. Enhancement of starch conversion efficiency with free and immobilized pullalanase and alpha-1,4 glucosidase

    SciTech Connect

    Kumar, A.R.; Venkatasubramanian, K.

    1982-02-01

    Glucoamylase and pullulanase were immobilized on reconstituted bovine-hide collagen membranes using the covalent azide linkage method. A pretanning step was incorporated into the immobilization procedure to enable the support matrix to resist proteolytic activity while accommodating an operating temperature of 50 degrees Celcius. The immobilized glucoamylase and pullulanase activities were 0.91 and 0.022 mg dextrose equivalent (DE) min-1 cm-2 of membrane, respectively. Immobilized glucoamylase had a half-life of 50 days while the immobilized pullulanase had a half-life of 7 days. This is a considerably improved stability over that reported by other researchers. The enzymes were studied in their free and immobilized forms on a variety of starch substrates including waxy maize, a material which contains 80% alpha-1-6-glucosidic linkages. Substrate concentrations ranged from 1% to a typical commercial concentration of 30%. Conversion efficiencies of 90-92% DE were obtained with free and immobilized glucoamylase preparations. Conversion enhancements of 4-5 mg of DE above this level were obtained by the use of pullulanase in its free or immobilized forms. Close examination of free pullulanase stability as a function of pH indicated improved thermal stability at higher pH values. At 50 degrees Celcius and pH 5.0, the free enzyme was inactivated after 24 hours. At pH 7.0, the enzyme still possessed one-half its activity after 72 hours. Studies were conducted in both batch and continuous total recycle reactors. All experiments were conducted at 50 degrees Celcius. Experiments conducted with coimmobilized enzymes proved quite promising. Levels of conversion equivalent to those obtained with the individually immobilized enzymes were realized. (Refs. 16).

  14. Development of a microfluidic “click chip” incorporating an immobilized Cu(I) catalyst

    PubMed Central

    Li, Hairong; Whittenberg, Joseph J.; Zhou, Haiying; Ranganathan, David; Desai, Amit V.; Koziol, Jan; Zeng, Dexing; Kenis, Paul J. A.; Reichert, David E.

    2015-01-01

    We have developed a microfluidic “click chip” incorporating an immobilized Cu(I) catalyst for click reactions. The microfluidic device was fabricated from polydimethylsiloxane (PDMS) bonded to glass and featured ~14,400 posts on the surface to improve catalyst immobilization. This design increased the immobilization efficiency and reduces the reagents’ diffusion time to active catalyst site. The device also incorporates five reservoirs to increase the reaction volume with minimal hydrodynamic pressure drop across the device. A novel water-soluble tris-(benzyltriazolylmethyl)amine (TBTA) derivative capable of stabilizing Cu(I), ligand 2, was synthesized and successfully immobilized on the chip surface. The catalyst immobilized chip surface was characterized by X-ray photoelectron spectroscopy (XPS). The immobilization efficiency was evaluated via radiotracer methods: the immobilized Cu(I) was measured as 1136±272 nmol and the surface immobilized Cu(I) density was 81±20 nmol cm−2. The active Cu(I)-ligand 2 could be regenerated up to five times without losing any catalyst efficiency. The “click” reaction of Flu568-azide and propargylamine was studied on chip for proof-of-principle. The on-chip reaction yields were ca. 82% with a 50 min reaction time or ca. 55% with a 15 min period at 37 °C, which was higher than those obtained in the conventional reaction. The on-chip “click” reaction involving a biomolecule, cyclo(RGDfK) peptide was also studied and demonstrated a conversion yield of ca. 98%. These encouraging results show promise on the application of the Cu(I) catalyst immobilized “click chip” for the development of biomolecule based imaging agents. PMID:25598970

  15. Production of xanthan gum by free and immobilized cells of Xanthomonas campestris and Xanthomonas pelargonii.

    PubMed

    Niknezhad, Seyyed Vahid; Asadollahi, Mohammad Ali; Zamani, Akram; Biria, Davoud

    2016-01-01

    Production of xanthan gum using immobilized cells of Xanthomonas campestris and Xanthomonas pelargonii grown on glucose or hydrolyzed starch as carbon sources was investigated. Calcium alginate (CA) and calcium alginate-polyvinyl alcohol-boric acid (CA-PVA) beads were used for the immobilization of cells. Xanthan titers of 8.2 and 9.2g/L were obtained for X. campestris cells immobilized in CA-PVA beads using glucose and hydrolyzed starch, respectively, whereas those for X. pelargonii were 8 and 7.9 g/L, respectively. Immobilized cells in CA-PVA beads were successfully employed in three consecutive cycles for xanthan production without any noticeable degradation of the beads whereas the CA beads were broken after the first cycle. The results of this study suggested that immobilized cells are advantageous over the free cells for xanthan production. Also it was shown that the cells immobilized in CA-PVA beads are more efficient than cells immobilized in CA beads for xanthan production. PMID:26526173

  16. Immobilization of leachable toxic soil pollutants by using oxidative enzymes. [Geotrichum candidum

    SciTech Connect

    Shannon, M.J.R.; Bartha, R.

    1988-07-01

    Screening of leachable toxic chemicals in a horseradish peroxidase-H/sub 2/O/sub 2/ immobilization system established that immobilization was promising for most phenolic pollutants but not for benzoic acid, 2,6-dinitrocresol, or dibutyl phthalate. The treatment did not mobilize inherently nonmobile pollutants such as anilines and benzo(a)pyrene. In a separate study, an extracellular laccase in the culture filtrate of Geotrichum candidum was selected from five fungal enzymes evaluated as a cost-effective substitute for horseradish peroxidase. This enzyme was used in demonstrating the immobilization and subsequent fate of /sup 14/C-labeled 4-methylphenol and 2,4-dichlorophenol in soil columns. When applied to Lakewood sand, 98.1% of 4-methylpheno was leached through with distilled water. Two days after immobilization treatment with the G. candidum culture filtrate, only 9.1% of the added 4-methylphenol was leached with the same volume of water. Of the more refractory test pollutant 2,4-dichlorophenol, 91.6% had leached at time zero and 48.5% had leached 1 day after the immobilization treatment. However, 2 weeks after immobilization, only 12.0% of the 2,4-dichlorophenol was leached compared with 61.7% from the control column that received no immobilization treatment. No remobilization of the bound pollutants was detected during 3- and 4-week incubation periods.

  17. Immobilization of tyrosinase on modified diatom biosilica: enzymatic removal of phenolic compounds from aqueous solution.

    PubMed

    Bayramoglu, Gulay; Akbulut, Aydin; Arica, M Yakup

    2013-01-15

    Acid and plasma treated diatom-biosilica particles, were modified with 3-aminopropyl triethoxysilane (APTES), and activated with glutaraldehyde. Then, tyrosinase was immobilized onto the pre-activated biosilica by covalent bonding. The biosilica properties were determined using SEM, and FTIR. The enzyme system has been characterized as a function of pH, temperature and substrate concentration. Optimum pH of the free and immobilized enzyme was found to be pH 7.0. Optimum temperatures of the free and immobilized enzymes were determined as 35 and 45 °C respectively. The biodegradation of phenolic compounds (i.e., phenol, para-cresol and phenyl acetate) has been studied by means of immobilized tyrosinase in a batch system. The immobilized tyrosinase retained about 74% of its original activity after 10 times repeated use in the batch system. Moreover, the storage stability of the tyrosinase-biosilica system resulted excellent, since they maintained more than 67% of the initial activity after eighth week storage. Highly porous structure of biosilica can provide large surface area for immobilization of high quantity enzyme. The porous structure of the biosilica can decrease diffusion limitation both substrate phenols and their products. Finally, the immobilized tyrosinase was used in a batch system for degradation of three different phenols. PMID:23245881

  18. Arsenic immobilization in the contaminated soil using poorly crystalline Fe-oxyhydroxy sulfate.

    PubMed

    Yang, Zhihui; Liu, Lin; Chai, Liyuan; Liao, Yingping; Yao, Wenbin; Xiao, Ruiyang

    2015-08-01

    A low crystalline Fe-oxyhydroxy sulfate (FeOS) was used to immobilize arsenic (As) in soils in this study. The effects of FeOS amount, treatment time and soil moisture on As immobilization were investigated. The results showed that water-soluble and NaHCO3-extractable As were immobilized by 53.4-99.8 and 13.8-73.3% respectively, with 1-10% of FeOS addition. The highest immobilization of water-soluble (98.5%) and NaHCO3-extractable arsenic (47.2%) was achieved under condition of 4% of FeOS and 80% of soil moisture. Further, more amounts of FeOS addition resulted in less time requirement for As immobilization. Sequential chemical extraction experiment revealed that easily mobile arsenic phase was transferred to less mobile phase. The FeOS-bonded As may play a significant role in arsenic immobilization. Under leaching with simulated acid rain at 60 times pore volumes, accumulation amount of As release from untreated soil and soil amended with FeOS were 98.4 and 1.2 mg, respectively, which correspond to 7.69 and 0.09% of total As amounts in soil. The result showed that the low crystalline FeOS can be used as a suitable additive for arsenic immobilization in soils. PMID:25911284

  19. Immobilization of microbial cell and yeast cell and its application to biomass conversion using radiation techniques

    NASA Astrophysics Data System (ADS)

    Kaetsu, Isao; Kumakura, Minoru; Fujimura, Takashi; Kasai, Noboru; Tamada, Masao

    The recent results of immobilization of cellulase-producing cells and ethanol-fermentation yeast by radiation were reported. The enzyme of cellulase produced by immobilized cells was used for saccharification of lignocellulosic wastes and immobilized yeast cells were used for fermentation reaction from glucose to ethanol. The wastes such as chaff and bagasse were treated by γ-ray or electron-beam irradiation in the presence of alkali and subsequent mechanical crushing, to form a fine powder less than 50 μm in diameter. On the other hand, Trichoderma reesei as a cellulase-producing microbial cell was immobilized on a fibrous carrier having a specific porous structure and cultured to produce cellulase. The enzymatic saccharification of the pretreated waste was carried out using the produced cellulase. The enhanced fermentation process to produce ethanol from glucose with the immobilized yeast by radiation was also studied. The ethanol productivity of immobilized growing yeast cells thus obtained was thirteen times that of free yeast cells in a 1:1 volume of liquid medium to immobilized yeast cells.

  20. Enzymatic removal of paracetamol from aqueous phase: horseradish peroxidase immobilized on nanofibrous membranes.

    PubMed

    Xu, Ran; Si, Yifang; Li, Fengting; Zhang, Bingru

    2015-03-01

    Paracetamol is a widely used as an analgesic and an antipyretic that can easily accumulate in aquatic environments. This study aimed to enhance paracetamol removal efficiency from water by combining the biocatalytic activity of horseradish peroxidase (HRP) with the adsorption of nanofibrous membrane. Poly(vinyl alcohol)/poly(acrylic acid)/SiO2 electrospinning nanofibrous membrane was prepared with fiber diameters of 200 to 300 nm. The membrane was made insoluble by the thermal cross-linking process. HRP, which was previously activated by 1,1'-carbonyldiimidazole, was covalently immobilized on the surface of nanofibers. Immobilized HRP retained 79.4 % of the activity of free HRP. The physical, chemical, and biochemical properties of the immobilized HRP and its application in paracetamol removal were comprehensively investigated. Immobilized HRP showed better storage capability and higher tolerance to the changes in pH and temperature than free HRP. Paracetamol removal rate by immobilized HRP (83.5 %) was similar to that of free HRP (84.4 %), but immobilized HRP showed excellent reusability. The results signify that enzyme immobilized on nanofibers has great application potential in water treatment. PMID:25269844

  1. Degradation of h-acid by free and immobilized cells of Alcaligenes latus

    PubMed Central

    Usha, M.S.; Sanjay, M.K.; Gaddad, S.M.; Shivannavar, C.T.

    2010-01-01

    Alcaligenes latus, isolated from industrial effluent, was able to grow in mineral salts medium with 50 ppm (0.15 mM) of H-acid as a sole source of carbon. Immobilization of Alcaligenes latus in Ca-alginate and polyurethane foam resulted in cells embedded in the matrices. When free cells and immobilized cells were used for biodegradation studies at concentration ranging from 100 ppm (0.3 mM) to 500 ppm (1.15 mM) degradation rate was enhanced with immobilized cells. Cells immobilized in polyurethane foam showed 100% degradation up to 350 ppm (1.05 mM) and 57% degradation at 500 ppm (1.5 mM). Degradation rate of Ca-alginate immobilized cells was less as compared to that of polyurethane foam immobilized cells. With Ca-alginate immobilized cells 100% degradation was recorded up to 200 ppm (0.6 mM) of H-acid and only 33% degradation was recorded at 500 ppm (1.5 mM) of H-acid. Spectral analysis of the products after H-acid utilization showed that the spent medium did not contain any aromatic compounds indicating H-acid degradation by A. latus. PMID:24031573

  2. Endothelial Cell Growth and Differentiation on Collagen-Immobilized Polycaprolactone Nanowire Surfaces.

    PubMed

    Leszczak, Victoria; Baskett, Dominique A; Popat, Ketul C

    2015-06-01

    The success of cardiovascular implants is associated with the development of an endothelium on material surface, critical to the prevention of intimal hyperplasia, calcification and thrombosis. A thorough understanding of the interaction between vascular endothelial cells and the biomaterial involved is essential in order to have a successful application which promotes healing and regeneration through integration with native tissue. In this study, we have developed collagen immobilized nanostructured surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of human microvascular endothelial cells (HMVECs). The nanowire surfaces were fabricated from polycaprolactone using a novel nanotemplating technique, and were immobilized with collagen utilizing an aminolysis method. The collagen immobilized nanowire surfaces were characterized using contact angle measurements, scanning electron microscopy and X-ray photoelectron spectroscopy. Human microvascular endothelial cells were used to evaluate the efficacy of the collagen immobilized nanowire surfaces to promote cell adhesion, proliferation, viability and differentiation. The results presented here indicate significantly higher cellular adhesion, proliferation and viability on nanowire and collagen immobilized surfaces as compared to the control surface. Further, HMVECs have a more elongated body and low shape factor on nanostructured surfaces. The differentiation potential of collagen immobilized nanowire surfaces was also evaluated by immunostaining and western blotting for key endothelial cell markers that are expressed when human microvascular endothelial cells are differentiated. Results indicate that expression of VE-cadherin is increased on collagen immobilized surfaces while the expression of von Willebrand factor is statistically similar on all surfaces. PMID:26353596

  3. Stereospecificity of mushroom tyrosinase immobilized on a chiral and a nonchiral support.

    PubMed

    Marín-Zamora, María Elisa; Rojas-Melgarejo, Francisco; García-Canovas, Francisco; García-Ruiz, Pedro Antonio

    2007-05-30

    Mushroom tyrosinase was immobilized from an extract onto glass beads covered with the cross-linked totally cinnamoylated derivates of d-sorbitol (sorbitol cinnamate) and glycerine (glycerine cinnamate). The enzyme was immobilized onto the support by direct adsorption, and the quantity of immobilized tyrosinase was higher for sorbitol cinnamate, the support with the higher number of esterified hydroxyls per unit of monosacharide, than for glycerine cinnamate. The results obtained from the stereospecificity study of the monophenolase and diphenolase activity of immobilized mushroom tyrosinase are reported. The enantiomers L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-alpha-methyldopa, DL-alpha-methyldopa, L-isoprenaline, DL-isoprenaline, L-adrenaline, DL-adrenaline, L-noradrenaline, and D-noradrenaline were assayed with tyrosinase immobilized on a chiral support (sorbitol cinnamate), whereas L-tyrosine, DL-tyrosine, D-tyrosine, L-dopa, DL-dopa, D-dopa, L-alpha-methyldopa, and DL-alpha-methyldopa were assayed with tyrosinase immobilized on a nonchiral support (glycerine cinnamate). The same Vmax(app) values for each series of enantiomers were obtained. However, the Km(app) values were different, the l isomers showing lower values than the dl isomers, whereas the highest Km(app) value was obtained with d isomers. No difference was observed in the stereospecificity of tyrosinase immobilized on a chiral (sorbitol cinnamate) or nonchiral (glycerine cinnamate) support. PMID:17488091

  4. Growth and metabolic activity of conventional and non-conventional yeasts immobilized in foamed alginate.

    PubMed

    Kregiel, Dorota; Berlowska, Joanna; Ambroziak, Wojciech

    2013-09-10

    The aim of this research was to study how the cell immobilization technique of forming foamed alginate gels influences the growth, vitality and metabolic activity of different yeasts. Two distinct strains were used, namely conventional yeast (exemplified by Saccharomyces cerevisiae) and a non-conventional strain (exemplified by Debaryomyces occidentalis). The encapsulation of the yeast cells was performed by the traditional process of droplet formation, but from a foamed alginate solution. The activities of two key enzymes, succinate dehydrogenase and pyruvate decarboxylase, together with the ATP content were measured in both the free and immobilized cells. This novel method of yeast cell entrapment had some notable effects. The number of living immobilized cells reached the level of 10(6)-10(7) per single bead, and was stable during the fermentation process. Reductions in both enzyme activity and ATP content were observed in all immobilized yeasts. However, S. cerevisiae showed higher levels of ATP and enzymatic activity than D. occidentalis. Fermentation trials with immobilized repitching cells showed that the tested yeasts adapted to the specific conditions. Nevertheless, the mechanical endurance of the carriers and the internal structure of the gel need to be improved to enable broad applications of alginate gels in industrial fermentation processes, especially with conventional yeasts. This is one of the few papers and patents that describe the technique of cell immobilization in foamed alginate and shows the fermentative capacities and activities of key enzymes in immobilized yeast cells. PMID:23931687

  5. Enhanced starch hydrolysis using α-amylase immobilized on cellulose ultrafiltration affinity membrane.

    PubMed

    Konovalova, Viktoriia; Guzikevich, Kateryna; Burban, Anatoliy; Kujawski, Wojciech; Jarzynka, Karolina; Kujawa, Joanna

    2016-11-01

    In order to prepare ultrafiltration membranes possessing biocatalytic properties, α-amylase has been immobilized on cellulose membranes. Enzyme immobilization was based on a covalent bonding between chitosan and a surface of cellulose membrane, followed by an attachment of Cibacron Blue F3G-A dye as affinity ligand. Various factors affecting the immobilization process, such as enzyme concentration, pH of modifying solution, zeta-potential of membrane surface, and stability of immobilized enzyme were studied. The applicability of immobilized α-amylase has been investigated in ultrafiltration processes. The immobilization of α-amylase on membrane surface allows to increase the value of mass transfer coefficient and to decrease the concentration polarization effect during ultrafiltration of starch solutions. The enzyme layer on the membrane surface prevents a rapid increase of starch concentration due to the amylase hydrolysis of starch in the boundary layer. The presented affinity immobilization technique allows also for the regeneration of membranes from inactivated enzyme. PMID:27516322

  6. Preparation of a Cu(II)-PVA/PA6 Composite Nanofibrous Membrane for Enzyme Immobilization

    PubMed Central

    Feng, Quan; Tang, Bin; Wei, Qufu; Hou, Dayin; Bi, Songmei; Wei, Anfang

    2012-01-01

    PVA/PA6 composite nanofibers were formed by electrospinning. Cu(II)-PVA/PA6 metal chelated nanofibers, prepared by the reaction between PVA/PA6 composite nanofibers and Cu2+ solution, were used as the support for catalase immobilization. The result of the experiments showed that PVA/PA6 composite nanofibers had an excellent chelation capacity for Cu2+ ions, and the structures of nanofibers were stable during the reaction with Cu2+ solution. The adsorption of Cu(II) onto PVA/PA6 composite nanofibers was studied by the Langmuir isothermal adsorption model. The maximum amount of coordinated Cu(II) (qm) was 3.731 mmol/g (dry fiber), and the binding constant (Kl) was 0.0593 L/mmol. Kinetic parameters were analyzed for both immobilized and free catalases. The value of Vmax (3774 μmol/mg·min) for the immobilized catalases was smaller than that of the free catalases (4878 μmol/mg·min), while the Km for the immobilized catalases was larger. The immobilized catalases showed better resistance to pH and temperature than that of free form, and the storage stabilities, reusability of immobilized catalases were significantly improved. The half-lives of free and immobilized catalases were 8 days and 24 days, respectively. PMID:23202922

  7. Novel functionalized fluorescent polymeric nanoparticles for immobilization of biomolecules

    NASA Astrophysics Data System (ADS)

    Jain, Swati; Chattopadhyay, Sruti; Jackeray, Richa; Abid, C. K. V. Zainul; Singh, Harpal

    2013-07-01

    Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable, monodisperse, spherical nano sized particles exhibiting high luminescence properties. Particles with 1% SLS (S1) showed good dispersion stability and fluorescence intensity and were chosen as ideal candidates for further immobilization studies. Steady state fluorescence studies showed 10 times higher fluorescence intensity of S1 nanoparticles than that of pyrene solution in solvent-toluene at the same concentration. Environmental factors such as pH, ionic strength and time were found to have no effect on fluorescence intensity of FPNPs. Surface β-di-ketone groups were utilized for the covalent immobilization of enzyme conjugated antibodies without any activation or pre-treatment of nanoparticles.Novel, size controlled fluorescent polymeric nanoparticles (FPNP) were synthesized having acetoacetoxy functionality on the surface for immobilization of biomolecules which can be utilized as biomarkers and labels in fluoroimmunoassays. Core-shell nanoparticles of poly(styrene, St-methyl methacrylate, MMA-acetoacetoxy ethyl methacrylate, AAEM), stabilized by various concentrations of surfactant, sodium lauryl sulphate (SLS), were obtained by facile miniemulsion co-polymerization encapsulated with pyrene molecules in their hydrophobic core. Analytical, spectroscopic and imaging characterization techniques revealed the formation of stable

  8. Prostaglandin E2 Restores Cancellous Bone to Immobilized Limb and Adds Bone to Overloaded Limb in Right Hindlimb Immobilization Rats

    NASA Technical Reports Server (NTRS)

    Li, M.; Jee, W. S. S.; Ke, H. Z.; Liang, X. G.; Lin, B. Y.; Ma, Y. F.; Setterberg, R. B.

    1993-01-01

    The purpose of this study was to determine whether prostaglandin E2 (PGE2) can restore cancellous bone mass and architecture to osteopenic, continuously immobilized (IM), proximal tibial metaphysis (PTM) in female rats. The right hindlimb of three and one-half-month-old Sprague-Dawley female rats were immobilized by right hindlimb immobilization (RHLI) in which the right hindlimb was underloaded and the contralateral left limb was overloaded during ambulation. After 4 or 12 weeks of RHLI, the rats were treated with 3 or 6 mg PGE2/kg/day and RHLI for 8 or 16 weeks. Bone histomorphometry was performed on microradiographs of PTM. Immobilization (IM) induced a transient cancellous bone loss and decreased trabecular thickness, number and node density, and increased free end density that established a new steady state after 4 weeks of IM. Three or 6 mg PGE2/kg/d for 8 weeks beginning at 4 or 12 weeks of IM completely restored cancellous bone mass (+127 to +188 percent) and structure to the age-related control levels in spite of continuous IM. Another 8 weeks of treatment maintained bone mass and architecture at these levels. No differences in cancellous bone mass and architecture were found between the overloaded PTM or RHLI rats and the age-related controls. However, 3 and 6 mg/kg/d of PGE2 treatment started at 4 or 12 weeks for 8 weeks significantly increased cancellous bone mass in the overloaded PTM (+45 to +74% of untreated controls), and another 8 weeks of treatment maintained bone mass at these levels. Our findings indicate that daily 3 or 6 mg PGE2/kg/d treatment restores and maintains PTM cancellous bone mass in continuously immobilized (right) tibiae, and adds and maintains extra bone to slightly overloaded PTM cancellous bone in female rats.

  9. Immobilization of Yarrowia lipolytica Lipase—A Comparison of Stability of Physical Adsorption and Covalent Attachment Techniques

    NASA Astrophysics Data System (ADS)

    Cunha, Aline G.; Fernández-Lorente, Gloria; Bevilaqua, Juliana V.; Destain, Jacqueline; Paiva, Lúcia M. C.; Freire, Denise M. G.; Fernández-Lafuente, Roberto; Guisán, Jose M.

    Lipase immobilization offers unique advantages in terms of better process control, enhanced stability, predictable decay rates and improved economics. This work evaluated the immobilization of a highly active Yarrowia lipolytica lipase (YLL) by physical adsorption and covalent attachment. The enzyme was adsorbed on octyl-agarose and octadecyl-sepabeads supports by hydrophobic adsorption at low ionic strength and on MANAE-agarose support by ionic adsorption. CNBr-agarose was used as support for the covalent attachment immobilization. Immobilization yields of 71, 90 and 97% were obtained when Y. lipolytica lipase was immobilized into octyl-agarose, octadecyl-sepabeads and MANAE-agarose, respectively. However, the activity retention was lower (34% for octyl-agarose, 50% for octadecyl-sepabeads and 61% for MANAE-agarose), indicating that the immobilized lipase lost activity during immobilization procedures. Furthermore, immobilization by covalent attachment led to complete enzyme inactivation. Thermal deactivation was studied at a temperature range from 25 to 45°C and pH varying from 5.0 to 9.0 and revealed that the hydrophobic adsorption on octadecyl-sepabeads produced an appreciable stabilization of the biocatalyst. The octadecyl-sepabeads biocatalyst was almost tenfold more stable than free lipase, and its thermal deactivation profile was also modified. On the other hand, the Y. lipolytica lipase immobilized on octyl-agarose and MANAE-agarose supports presented low stability, even less than the free enzyme.

  10. Covalent immobilization of Candida rugosa lipase on aldehyde functionalized hydrophobic support and the application for synthesis of oleic acid ester.

    PubMed

    Temoçin, Zülfikar

    2013-01-01

    This study focuses on Candida rugosa lipase (CRL) immobilization by covalent attachment on poly(ethylene terephthalate)-grafted glycidyl methacrylate (PET-g-GMA) fiber. The immobilization yielded a protein loading of 2.38 mg g(-1) of PET-g-GMA fiber. The performances of the immobilized and free CRLs were evaluated with regard to hydrolysis of olive oil and esterification of oleic acid. The optimum activity pH of the CRL was changed by immobilization to neutral range. The maximum activity of the free and immobilized CRLs occurred at 40 and 45 °C respectively. The immobilized lipase retained 65% of its original activity at 50 °C for 2 h. It was found that the immobilized lipase stored at 4 °C retained 90% of its original activity after 35 days, whereas the free lipase stored at 4 °C retained 69% of its original activity after the same period. In the esterification experiments, the immobilized CRL could maintain a high activity at a water content range from 1.5 to 6% (v/v), while the activity of free CRL showed a clear dependence on water content and decreased rapidly at above 3% (v/v) water content. In addition, after five reuses, the esterification percent yield of the immobilized CRL slightly decreased from 29 to 27%. PMID:23574345

  11. Two-week cast immobilization induced chronic widespread hyperalgesia in rats.

    PubMed

    Ohmichi, Y; Sato, J; Ohmichi, M; Sakurai, H; Yoshimoto, T; Morimoto, A; Hashimoto, T; Eguchi, K; Nishihara, M; Arai, Y-C P; Ohishi, H; Asamoto, K; Ushida, T; Nakano, T; Kumazawa, T

    2012-03-01

    It has been postulated that physical immobilization is an essential factor in developing chronic pain after trauma or surgery in an extremity. However, the mechanisms of sustained immobilization-induced chronic pain remain poorly understood. The present study, therefore, aimed to develop a rat model for chronic post-cast pain (CPCP) and to clarify the mechanism(s) underlying CPCP. To investigate the effects of cast immobilization on pain behaviours in rats, one hindlimb was immobilized for 2 weeks with a cast and remobilization was conducted for 10 weeks. Cast immobilization induced muscle atrophy and inflammatory changes in the immobilized hindlimb that began 2 h after cast removal and continued for 1 week. Spontaneous pain-related behaviours (licking and reduction in weight bearing) in the immobilized hindlimb were observed for 2 weeks, and widespread mechanical hyperalgesia in bilateral calves, hindpaws and tail all continued for 5-10 weeks after cast removal. A sciatic nerve block with lidocaine 24 h after cast removal transitorily abolished bilateral mechanical hyperalgesia in CPCP rats, suggesting that sensory inputs originating in the immobilized hindlimb contribute to the mechanism of both ipsilateral and contralateral hyperalgesia. Intraperitoneal injection of the free radical scavengers 4-hydroxy-2,2,6,6-tetramethylpiperydine-1-oxy1 or N-acetylcysteine 24 h after cast removal clearly inhibited mechanical hyperalgesia in bilateral calves and hindpaws in CPCP rats. These results suggest that cast immobilization induces ischaemia/reperfusion injury in the hindlimb and consequent production of oxygen free radicals, which may be involved in the mechanism of widespread hyperalgesia in CPCP rats. PMID:22337282

  12. Simultaneous and sequential co-immobilization of glucose oxidase and catalase onto florisil.

    PubMed

    Ozyilmaz, Gul; Tukel, S Seyhan

    2007-06-01

    The co-immobilization of Aspergillus niger glucose oxidase (GOD) with bovine liver catalase (CAT) onto florisil (magnesium silicate-based porous carrier) was investigated to improve the catalytic efficiency of GOD against H2O2 inactivation. The effect of the amount of bound CAT on the GOD activity was also studied for 12 different initial combinations of GOD and CAT, using simultaneous and sequential coupling. The sequentially co-immobilized GOD-CAT showed a higher efficiency than the simultaneously co-immobilized GOD-CAT in terms of the GOD activity and economic costs. The highest activity was shown by the sequentially co-immobilized GOD-CAT when the initial amounts of GOD and CAT were 10 mg and 5 mg per gram of carrier. The optimum pH, buffer concentration, and temperature for GOD activity for the same co-immobilized GOD-CAT sample were then determined as pH 6.5, 50 mM, and 30 degrees C, respectively. When compared with the individually immobilized GOD, the catalytic activity of the co-immobilized GOD-CAT was 70% higher, plus the reusability was more than two-fold. The storage stability of the co-immobilized GOD-CAT was also found to be higher than that of the free form at both 5 degrees C and 25 degrees C. The increased GOD activity and reusability resulting from the co-immobilization process may have been due to CAT protecting GOD from inactivation by H2O2 and supplying additional O2 to the reaction system. PMID:18050914

  13. Immobilization of Rocky Flats Graphite Fines Residue

    SciTech Connect

    Rudisill, T.S.

    1999-04-06

    The development of the immobilization process for graphite fines has proceeded through a series of experimental programs. The experimental procedures and results from each series of experiments are discussed in this report.

  14. Immobilization Technologies in Probiotic Food Production

    PubMed Central

    Mitropoulou, Gregoria; Nedovic, Viktor; Goyal, Arun; Kourkoutas, Yiannis

    2013-01-01

    Various supports and immobilization/encapsulation techniques have been proposed and tested for application in functional food production. In the present review, the use of probiotic microorganisms for the production of novel foods is discussed, while the benefits and criteria of using probiotic cultures are analyzed. Subsequently, immobilization/encapsulation applications in the food industry aiming at the prolongation of cell viability are described together with an evaluation of their potential future impact, which is also highlighted and assessed. PMID:24288597

  15. Denitrification using a membrane-immobilized biofilm

    SciTech Connect

    McCleaf, P.R. ); Schroeder, E.D. . Dept. of Civil and Environmental Engineering)

    1995-03-01

    Immobilized bacterial cell technology was applied, on a bench scale, to the selective removal of nitrate from contaminated water, together with the segregation of denitrifying bacteria and the carbon energy source from the treated water. The two-chambered reactor, with a microporous membrane for bacterial cell immobilization, performed at an average denitrification rate of 5,800 mg nitrate-nitrogen (NO[sub 3][sup [minus

  16. Ceramification: A plutonium immobilization process

    SciTech Connect

    Rask, W.C.; Phillips, A.G.

    1996-05-01

    This paper describes a low temperature technique for stabilizing and immobilizing actinide compounds using a combination process/storage vessel of stainless steel, in which measured amounts of actinide nitrate solutions and actinide oxides (and/or residues) are systematically treated to yield a solid article. The chemical ceramic process is based on a coating technology that produces rare earth oxide coatings for defense applications involving plutonium. The final product of this application is a solid, coherent actinide oxide with process-generated encapsulation that has long-term environmental stability. Actinide compounds can be stabilized as pure materials for ease of re-use or as intimate mixtures with additives such as rare earth oxides to increase their degree of proliferation resistance. Starting materials for the process can include nitrate solutions, powders, aggregates, sludges, incinerator ashes, and others. Agents such as cerium oxide or zirconium oxide may be added as powders or precursors to enhance the properties of the resulting solid product. Additives may be included to produce a final product suitable for use in nuclear fuel pellet production. The process is simple and reduces the time and expense for stabilizing plutonium compounds. It requires a very low equipment expenditure and can be readily implemented into existing gloveboxes. The process is easily conducted with less associated risk than proposed alternative technologies.

  17. Immobilization induces a very rapid increase in osteoclast activity

    NASA Astrophysics Data System (ADS)

    Heer, Martina; Baecker, Natalie; Mika, Claudia; Boese, Andrea; Gerzer, Rupert

    2005-07-01

    We studied in a randomized, strictly controlled cross-over design, the effects of 6 days 6° head-down tilt bed rest (HDT) in eight male healthy subjects in our metabolic ward. The study consisted of two periods (phases) of 11 days each in order to allow for the test subjects being their own controls. Both study phases were identical with respect to environmental conditions, study protocol and diet. Two days before arriving in the metabolic ward the subjects started with a diet. The diet was continued in the metabolic ward. The metabolic ward period (1l days) was divided into three parts: 4 ambulatory days, 6 days either HDT or control and 1 recovery day. Continuous urine collection started on the first day in the metabolic ward to analyze calcium excretion and bone resorption markers. On the 2nd ambulatory day in the metabolic ward and on the 5th day in HDT or control blood was drawn to analyze serum calcium, parathyroid hormone, and bone formation markers. Urinary calcium excretion was, as early as the first day in immobilization, increased (p<0.01). CTX- and NTX-excretion stayed unchanged in the first 24 h in HDT compared to the control. But already on the 2nd day of immobilization, both bone resorption markers significantly increased. We conclude from these results—pronounced rise of bone resorption markers—that already 24 h of immobilization induce a significant rise in osteoclast activity in healthy subjects. Thus, it appears possible to use short-term bed rest studies as a first step for the development of countermeasures to immobilization.

  18. A validated classification for external immobilization of the cervical spine.

    PubMed

    Holla, Micha; Huisman, Joske M R; Hosman, Allard J F

    2013-10-01

    Study Design Interobserver and intraobserver reliability study. Objective The aim of this study is to validate a new classification system of external cervical spine immobilization devices by measuring the interobserver and intraobserver agreement. Methods A classification system, with five main categories, based on the anatomical regions on which the device supports, was created. A total of 28 independent observers classified 50 photographs of different devices, designed to immobilize the cervical spine according to the new proposed classification system. At least 2 weeks later, the same devices were classified again in a new random order. Before and after the classification, all the participants answered questions about the usefulness of the proposed classification. Results The mean interobserver and intraobserver agreement Fleiss' kappa was 0.88 and 0.91, respectively. Both are, according to the interpretation described by Landis and Koch, "almost perfect." A majority of the participators answered that they needed a classification (89%) and considered the classification to be clear (96%). All the participants considered the classification to be useful in clinical practice. Conclusion This study showed that the new classification of external cervical spine immobilizers, based on anatomical support areas, has an excellent interobserver and intraobserver agreement. Furthermore, the study participants considered the proposed classification to be clear and useful in clinical practice. As the majority of patients with cervical spine injuries are treated with external immobilization devices, this new classification system can improve the closed treatment of cervical spine injuries in daily clinical practice. Furthermore, it makes reproducible comparisons between groups possible, which are essential for further evolution of evidence-based spine care. PMID:24436704

  19. Immobilization of Fast Reactor First Cycle Raffinate

    SciTech Connect

    Langley, K. F.; Partridge, B. A.; Wise, M.

    2003-02-26

    This paper describes the results of work to bring forward the timing for the immobilization of first cycle raffinate from reprocessing fuel from the Dounreay Prototype Fast Reactor (PFR). First cycle raffinate is the liquor which contains > 99% of the fission products separated from spent fuel during reprocessing. Approximately 203 m3 of raffinate from the reprocessing of PFR fuel is held in four tanks at the UKAEA's site at Dounreay, Scotland. Two methods of immobilization of this high level waste (HLW) have been considered: vitrification and cementation. Vitrification is the standard industry practice for the immobilization of first cycle raffinate, and many papers have been presented on this technique elsewhere. However, cementation is potentially feasible for immobilizing first cycle raffinate because the heat output is an order of magnitude lower than typical HLW from commercial reprocessing operations such as that at the Sellafield site in Cumbria, England. In fact, it falls within the upper end of the UK definition of intermediate level waste (ILW). Although the decision on which immobilization technique will be employed has yet to be made, initial development work has been undertaken to identify a suitable cementation formulation using inactive simulant of the raffinate. An approach has been made to the waste disposal company Nirex to consider the disposability of the cemented product material. The paper concentrates on the process development work that is being undertaken on cementation to inform the decision making process for selection of the immobilization method.

  20. Mechanism of Sperm Immobilization by Escherichia coli

    PubMed Central

    Prabha, Vijay; Sandhu, Ravneet; Kaur, Siftjit; Kaur, Kiranjeet; Sarwal, Abha; Mavuduru, Ravimohan S.; Singh, Shravan Kumar

    2010-01-01

    Aim. To explore the influence of Escherichia coli on the motility of human spermatozoa and its possible mechanism. Methods. Highly motile preparations of spermatozoa from normozoospermic patients were coincubated with Escherichia coli for 4 hours. At 1, 2 and 4 hours of incubation, sperm motility was determined. The factor responsible for sperm immobilization without agglutination was isolated and purified from filtrates. Results. This report confirms the immobilization of spermatozoa by E. coli and demonstrates sperm immobilization factor (SIF) excreted by E. coli. Further this factor was purified by ammonium sulfate precipitation, gel permeation chromatography, and ion-exchange chromatography. Purified SIF (56 kDa) caused instant immobilization without agglutination of human spermatozoa at 800 μg/mL and death at 2.1 mg/mL. Spermatozoa incubated with SIF revealed multiple and profound alterations involving all superficial structures of spermatozoa as observed by scanning electron microscopy. Conclusion. In conclusion, these results have shown immobilization of spermatozoa by E. coli and demonstrate a factor (SIF) produced and secreted by E. coli which causes variable structural damage as probable morphological correlates of immobilization. PMID:20379358

  1. Surface cell immobilization within perfluoroalkoxy microchannels

    NASA Astrophysics Data System (ADS)

    Stojkovič, Gorazd; Krivec, Matic; Vesel, Alenka; Marinšek, Marjan; Žnidaršič-Plazl, Polona

    2014-11-01

    Perfluoroalkoxy (PFA) is one of the most promising materials for the fabrication of cheap, solvent resistant and reusable microfluidic chips, which have been recently recognized as effective tools for biocatalytic process development. The application of biocatalysts significantly depends on efficient immobilization of enzymes or cells within the reactor enabling long-term biocatalyst use. Functionalization of PFA microchannels by 3-aminopropyltriethoxysilane (ATPES) and glutaraldehyde was used for rapid preparation of microbioreactors with surface-immobilized cells. X-ray photoelectron spectroscopy and scanning electron microscopy were used to accurately monitor individual treatment steps and to select conditions for cell immobilization. The optimized protocol for Saccharomyces cerevisiae immobilization on PFA microchannel walls comprised ethanol surface pretreatment, 4 h contacting with 10% APTES aqueous solution, 10 min treatment with 1% glutaraldehyde and 20 min contacting with cells in deionized water. The same protocol enabled also immobilization of Escherichia coli, Pseudomonas putida and Bacillus subtilis cells on PFA surface in high densities. Furthermore, the developed procedure has been proved to be very efficient also for surface immobilization of tested cells on other materials that are used for microreactor fabrication, including glass, polystyrene, poly (methyl methacrylate), polycarbonate, and two olefin-based polymers, namely Zeonor® and Topas®.

  2. Nanoscale dielectrophoretic spectroscopy of individual immobilized mammalian blood cells.

    PubMed

    Lynch, Brian P; Hilton, Al M; Simpson, Garth J

    2006-10-01

    Dielectrophoretic force microscopy (DEPFM) and spectroscopy have been performed on individual intact surface-immobilized mammalian red blood cells. Dielectrophoretic force spectra were obtained in situ in approximately 125 ms and could be acquired over a region comparable in dimension to the effective diameter of a scanning probe microscopy tip. Good agreement was observed between the measured dielectrophoretic spectra and predictions using a single-shell cell model. In addition to allowing for highly localized dielectric characterization, DEPFM provided a simple means for noncontact imaging of mammalian blood cells under aqueous conditions. These studies demonstrate the feasibility of using DEPFM to monitor localized changes in membrane capacitance in real time with high spatial resolution on immobilized cells, complementing previous studies of mobile whole cells and cell suspensions. PMID:16798803

  3. Cell immobilization on polymer by air atmospheric pressure plasma jet treatment

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Hwan; Kwon, Jae-Sung; Om, Ji-yeon; Kim, Yong-Hee; Choi, Eun-Ha; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2014-08-01

    The study of cell immobilization on delicate polymer by an air atmospheric pressure plasma jet (AAPPJ) is required for its medical application. The aim of this study was to evaluate whether AAPPJ treatment induce cell immobilization effect on delicate polymers without significant change of surface roughness by AAPPJ treatment. After surface roughness, dynamic contact angle, and chemical characteristics were investigated, the immobilization effect was evaluated with the mouse fibroblast L929 cell line. Surface roughness change was not observed (P > 0.05) in either delicate dental wax or polystyrene plate (PSP) as advancing and receding contact angles significantly decreased (P < 0.05), thanks to decreased hydrocarbon and formation of oxygen-related functional groups in treated PSP. Adherent L929 cells with elongated morphology were found in treated PSP along with the formation of immobilization markers vinculin and actin cytoskeleton. Increased PTK2 gene expression upregulated these markers on treated PSP.

  4. Histological and compositional responses of bone to immobilization and other experimental conditions

    NASA Technical Reports Server (NTRS)

    Brown, R. J.; Niklowitz, W. J.

    1985-01-01

    Histological techniques were utilized for evaluating progressive changes in tibial compact bone in adult male monkeys during chronic studies of immobilization-associated osteopenia. The animals were restrained in a semirecumbent position which reduces normally occurring stresses in the lower extremities and results in bone mass loss. The longest immobilization studies were of seven months duration. Losses of haversian bone tended to occur predominatly in the proximal tibia and were characterized by increased activation with excessive depth of penetration of osteoclastic activity. There was no apparent regulation of the size and orientation of resorption cavities. Rapid bone loss seen during 10 weeks of immobilization appeared to be due to unrestrained osteoclastic activity without controls and regulation which are characteristic of adaptive systems. The general pattern of loss persisted throughout 7 months of immobilization. Clear cut evidence of a formation phase in haversian bone was seen only after two months of reambulation.

  5. Development of 170 MHz Electrodeless Quartz-Crystal Microbalance Immunosensor with Nonspecifically Immobilized Receptor Proteins

    NASA Astrophysics Data System (ADS)

    Hirotsugu Ogi,; Hironao Nagai,; Yuji Fukunishi,; Taiji Yanagida,; Masahiko Hirao,; Masayoshi Nishiyama,

    2010-07-01

    Staphylococcus aureus protein A (SPA) shows high nonspecific binding affinity on a naked quartz surface, and it can be used as the receptor protein for detecting immunoglobulin G (IgG), the most important immunoglobulin. The immunosensor ability, however, significantly depends on the immobilization procedure. In this work, the effect of the nonspecific immobilization procedure on the sensor sensitivity is studied using a home-built electrodeless quartz-crystal microbalance (QCM) biosensor. The pure-shear vibration of a 9.7-μm-thick AT-cut quartz plate is excited and detected in liquids by the line antenna located outside the flow channel. SPA molecules are immobilized on the quartz surfaces, and human IgG is injected to monitor the binding reaction between SPA and IgG. This study reveals that a long (nearly 24 h) immersion procedure is required for immobilizing SPA to achieve the tight biding with the quartz surfaces.

  6. Development of 170 MHz Electrodeless Quartz-Crystal Microbalance Immunosensor with Nonspecifically Immobilized Receptor Proteins

    NASA Astrophysics Data System (ADS)

    Ogi, Hirotsugu; Nagai, Hironao; Fukunishi, Yuji; Yanagida, Taiji; Hirao, Masahiko; Nishiyama, Masayoshi

    2010-07-01

    Staphylococcus aureus protein A (SPA) shows high nonspecific binding affinity on a naked quartz surface, and it can be used as the receptor protein for detecting immunoglobulin G (IgG), the most important immunoglobulin. The immunosensor ability, however, significantly depends on the immobilization procedure. In this work, the effect of the nonspecific immobilization procedure on the sensor sensitivity is studied using a home-built electrodeless quartz-crystal microbalance (QCM) biosensor. The pure-shear vibration of a 9.7-µm-thick AT-cut quartz plate is excited and detected in liquids by the line antenna located outside the flow channel. SPA molecules are immobilized on the quartz surfaces, and human IgG is injected to monitor the binding reaction between SPA and IgG. This study reveals that a long (nearly 24 h) immersion procedure is required for immobilizing SPA to achieve the tight biding with the quartz surfaces.

  7. Does single-amino-acid replacement work in favor of or against improvement of the thermostability of immobilized enzyme?

    PubMed Central

    Koizumi, J; Zhang, M; Imanaka, T; Aiba, S

    1990-01-01

    Thermostabilities of kanamycin nucleotidyltransferase and of its mutants that became thermostable, in the free state, because of single-amino-acid replacements were studied after immobilization of the enzymes on cyanogen bromide-activated Sephadex G-200 particles. Lys in place of Gln at position 102 decreased the thermostability of the immobilized enzyme, whereas replacement with other amino acids enhanced it. PMID:2176451

  8. Immobilization of uranium in contaminated soil by natural apatite addition

    SciTech Connect

    Mrdakovic Popic, Jelena; Stojanovic, Mirjana; Milosevic, Sinisa; Iles, Deana; Zildzovic, Snezana

    2007-07-01

    Available in abstract form only. Full text of publication follows: The goal of this study was to evaluate the effectiveness of Serbian natural mineral apatite as soil additive for reducing the migration of uranium from contaminated sediments. In laboratory study we investigated the sorption properties of domestic apatite upon different experimental conditions, such as pH, adsorbent mass, reaction period, concentration of P{sub 2}O{sub 5} in apatite, solid/liquid ratio. In second part of study, we did the quantification of uranium in soil samples, taken from uranium mine site 'Kalna', by sequential extraction method. The same procedure was, also, used for uranium determination in contaminated soil samples after apatite addition, in order to determine the changes in U distribution in soil fraction. The obtained results showed the significant level of immobilization (96.7%) upon certain conditions. Increase of %P{sub 2}O{sub 5} in apatite and process of mechano-chemical activation led to increase of immobilization capacity from 17.50% till 91.64%. The best results for uranium binding were obtained at pH 5.5 and reaction period 60 days (98.04%) The sequential extraction showed the presence of uranium (48.2%) in potentially available soil fractions, but with the apatite addition uranium content in these fractions decreased (30.64%), what is considering environmental aspect significant fact. In situ immobilization of radionuclide using inexpensive sequestering agents, such as apatite, is very adequate for big contaminated areas of soil with low level of contamination. This investigation study on natural apatite from deposit 'Lisina' Serbia was the first one of this type in our country. Key words: apatite, uranium, immobilization, soil, contamination. (authors)

  9. Immobilized high-level waste interim storage alternatives generation and analysis and decision report

    SciTech Connect

    CALMUS, R.B.

    1999-05-18

    This report presents a study of alternative system architectures to provide onsite interim storage for the immobilized high-level waste produced by the Tank Waste Remediation System (TWRS) privatization vendor. It examines the contract and program changes that have occurred and evaluates their impacts on the baseline immobilized high-level waste (IHLW) interim storage strategy. In addition, this report documents the recommended initial interim storage architecture and implementation path forward.

  10. Immobilization of recombinant vault nanoparticles on solid substrates.

    PubMed

    Xia, Yun; Ramgopal, Yamini; Li, Hai; Shang, Lei; Srinivas, Parisa; Kickhoefer, Valerie A; Rome, Leonard H; Preiser, Peter R; Boey, Freddy; Zhang, Hua; Venkatraman, Subbu S

    2010-03-23

    Native vaults are nanoscale particles found abundantly in the cytoplasm of most eukaryotic cells. They have a capsule-like structure with a thin shell surrounding a "hollow" interior compartment. Recombinant vault particles were found to self-assemble following expression of the major vault protein (MVP) in a baculovirus expression system, and these particles are virtually identical to native vaults. Such particles have been recently studied as potential delivery vehicles. In this study, we focus on immobilization of vault particles on a solid substrate, such as glass, as a first step to study their interactions with cells. To this end, we first engineered the recombinant vaults by fusing two different tags to the C-terminus of MVP, a 3 amino acid RGD peptide and a 12 amino acid RGD-strep-tag peptide. We have demonstrated two strategies for immobilizing vaults on solid substrates. The barrel-and-cap structure of vault particles was observed for the first time, by atomic force microscopy (AFM), in a dry condition. This work proved the feasibility of immobilizing vault nanoparticles on a material surface, and the possibility of using vault nanoparticles as localized and sustainable drug carriers as well as a biocompatible surface moiety. PMID:20146454

  11. Characterization of protein-immobilized polystyrene nanoparticles using impedance spectroscopy.

    PubMed

    Park, Soo-In; Lee, Sang-Yup

    2014-10-01

    A novel approach for characterization of non-conductive protein-immobilized nanoparticles using AC impedance spectroscopy combined with conductive atomic force microscopy was examined. As AC impedance spectroscopy can provide information on diverse electrical properties such as capacitance and inductance, it is applicable to the characterization of non-conductive substances. Several non-conductive protein-immobilized polystyrene nanoparticles were analyzed using AC impedance spectroscopy, and their impedance spectra were used as markers for nanoparticle identification. Analyses of impedance signals using an electrical circuit model established that the capacitance and inductance of each nanoparticle changed with the adsorbed protein and that impedance spectral differences were characteristic properties of the proteins. From this study, AC impedance spectroscopy was shown to be a useful tool for characterization of non-conductive nanoparticles and is expected to be applicable to the development of sensors for nanomaterials. PMID:25942903

  12. Immobilization of radioactive waste by cementation with purified kaolin clay.

    PubMed

    Osmanlioglu, A Erdal

    2002-01-01

    A study is undertaken to determine the waste immobilization performance of low-level wastes in cement-clay mixtures. Liquid low-level wastes are precipitated using chemical methods, followed by solidification in drums. Solidification is done using cementation processes. Long-term leaching rates of the radionuclides are used as indicators of immobilization performance of solidified waste forms. In addition to evaluating the effects of kaolin clay on the leaching properties of the cemented waste forms, the effect of addition of kaolin on the strength of the cemented waste form is also investigated. The long term leaching tests show that inclusion of kaolin in cement reduces the leaching rates of the radionuclides significantly. However, clay additions in excess of 15 wt.% causes a significant decrease in the hydrolytic stability of cemented waste form. It is found that the best waste isolation, without causing a loss in the mechanical strength, is obtained when the kaolin content in cement is 5%. PMID:12092756

  13. Electro-enzymatic degradation of chlorpyrifos by immobilized hemoglobin.

    PubMed

    Tang, Tiantian; Dong, Jing; Ai, Shiyun; Qiu, Yanyan; Han, Ruixia

    2011-04-15

    Electro-enzymatic processes, which are enzyme catalysis combined with electrochemical reactions, have been used in the degradation of many environment pollutants. For some pollutants, the catalytic mechanisms of the electrochemical-enzyme reaction are still poorly understood. In this paper, the degradation of chlorpyrifos by a combination of immobilized hemoglobin and in situ generated hydrogen peroxide is reported for the first time. Hemoglobin was immobilized on graphite felts to catalyze the removal of chlorpyrifos in an electrochemical-enzyme system. Under the optimal conditions, more than 98% of the chlorpyrifos was degraded. Furthermore, the degradation products of chlorpyrifos were also studied and identified using liquid chromatography-mass spectrometry analysis. The results suggest a possible degradation mechanism for chlorpyrifos with low power and high efficiency, reveal the feasibility of hemoglobin as a substitute for some expensive natural enzymes, and demonstrate the application of an electro-enzymatic process in the treatment of organophosphorus compounds in wastewater. PMID:21316849

  14. Immobilization of Rubia tinctorum L. Suspension Cultures and Biomass Production.

    PubMed

    Nartop, Pınar

    2016-01-01

    Plants are natural sources of valuable secondary metabolites used as pharmaceuticals, agrochemicals, flavors, fragrances, colors, biopesticides, and food additives. There is an increasing demand to obtain these metabolites through more productive plant tissue applications and cell culture methods due to the importance of secondary metabolites.Immobilization of plant cells is a method used in plant cell cultures to induce secondary metabolite production. In this method, plant cells are fixed in or on a supporting material or matrix such as agar, agarose, calcium alginate, glass, or polyurethane foam. In the present study, three natural lignocellulosic materials, loofah sponge, and the long fibers of sisal and jute, were used to immobilize suspended R. tinctorum cells. PMID:27108315

  15. Immobilization of Laccase in Alginate-Gelatin Mixed Gel and Decolorization of Synthetic Dyes

    PubMed Central

    Mogharabi, Mehdi; Nassiri-Koopaei, Nasser; Bozorgi-Koushalshahi, Maryam; Nafissi-Varcheh, Nastaran; Bagherzadeh, Ghodsieh; Faramarzi, Mohammad Ali

    2012-01-01

    Alginate-gelatin mixed gel was applied to immobilized laccase for decolorization of some synthetic dyes including crystal violet. The immobilization procedure was accomplished by adding alginate to a gelatin solution containing the enzyme and the subsequent dropwise addition of the mixture into a stirred CaCl2 solution. The obtained data showed that both immobilized and free enzymes acted optimally at 50°C for removal of crystal violet, but the entrapped enzyme showed higher thermal stability compared to the free enzyme. The immobilized enzyme represented optimum decolorization at pH 8. Reusability of the entrapped laccase was also studied and the results showed that ca. 85% activity was retained after five successive cycles. The best removal condition was applied for decolorization of seven other synthetic dyes. Results showed that the maximum and minimum dye removal was related to amido black 10B and eosin, respectively. PMID:22899898

  16. Characterization of immobilization methods of antiviral antibodies in serum for electrochemical biosensors

    NASA Astrophysics Data System (ADS)

    Huy, Tran Quang; Hanh, Nguyen Thi Hong; Van Chung, Pham; Anh, Dang Duc; Nga, Phan Thi; Tuan, Mai Anh

    2011-06-01

    In this paper, we describes different methods to immobilize Japanese encephalitis virus (JEV) antibodies in human serum onto the interdigitated surface of a microelectrode sensor for optimizing electrochemical detection: (1) direct covalent binding to the silanized surface, (2) binding to the silanized surface via a cross-linker of glutaraldehyde (GA), (3) binding to glutaraldehyde/silanized surface via goat anti-human IgG polyclonal antibody and (4) binding to glutaraldehyde/silanized surface via protein A (PrA). Field emission scanning electron microscopy, Fourier transform infrared spectrometry, and fluorescence microscopy are used to verify the characteristics of antibodies on the interdigitated surface after the serum antibodies immobilization. The analyzed results indicate that the use of protein A is an effective choice for immobilization and orientation of antibodies in serum for electrochemical biosensors. This study provides an advantageous immobilization method of serum containing antiviral antibodies to develop electrochemical biosensors for preliminary screening of viruses in clinical samples from outbreaks.

  17. Immobilization of a Pleurotus ostreatus Laccase Mixture on Perlite and Its Application to Dye Decolourisation

    PubMed Central

    Salatino, Piero; Sannia, Giovanni

    2014-01-01

    In the present study, a crude laccase preparation from Pleurotus ostreatus was successfully immobilized on perlite, a cheap porous silica material, and tested for Remazol Brilliant Blue R (RBBR) decolourisation in a fluidized bed recycle reactor. Results showed that RBBR decolourisation is mainly due to enzyme action despite the occurrence of dye adsorption-related enzyme inhibition. Fine tuning of immobilization conditions allowed balancing the immobilization yield and the resulting rate of decolourisation, with the adsorption capacity of the solid biocatalyst. In the continuous lab scale reactor, a maximum conversion degree of 56.1% was achieved at reactor space-time of 4.2 h. Stability and catalytic parameters of the immobilized laccases were also assessed in comparison with the soluble counterparts, revealing an increase in stability, despite a reduction of the catalytic performances. Both effects are most likely ascribable to the occurrence of multipoint attachment phenomena. PMID:24895564

  18. Effect of immobilization stress on the level of macroergic phosphates in the blood of rats

    NASA Technical Reports Server (NTRS)

    Pudov, V. I.; Sosenkov, V. A.

    1980-01-01

    The effect of immobilization for 1, 2, and 24 hours, and of daily (for 2 hours for 7 days) immobilization on the blood nucleotide (ATP, ADP, AMP) level was studied on 79 male rats. A progressive reduction of the ATP content was most pronounced in immobilization for 24 hours. This was accompanied by an increase of lymphopenia and eosinopenia. A fall of the relative weight of the thymus and a weight gain of the adrenal glands was observed along with a reduction of ascorbic acid concentration in both of them. In case of daily immobilization for 2 hours, the ATP and ADP content on the 1st and 2nd day was below the normal level, and then showed a gradual increase, with complete normalization in 6-7 days, except for inorganic phosphorus the level of which remained lower than normal.

  19. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry

    PubMed Central

    Zhu, Chenggang; Zhu, Xiangdong; Landry, James P.; Cui, Zhaomeng; Li, Quanfu; Dang, Yongjun; Mi, Lan; Zheng, Fengyun; Fei, Yiyan

    2016-01-01

    Small-molecule microarray (SMM) is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%. PMID:26999137

  20. Development of a new antibacterial biomaterial by tetracycline immobilization on calcium-alginate beads.

    PubMed

    Ozseker, Emine Erdogan; Akkaya, Alper

    2016-10-20

    In recent years, increasing risk of infection, caused by resistant microorganism to antibiotics, has become the limelight discovery of new and natural antibacterial materials. Heavy metals, such as silver, copper, mercury and titanium, have antibacterial activity. Products, which improved these metals, do not have stable antibacterial property. Therefore, use of these products is restricted. The aim of this study was to immobilize tetracycline to alginate and improve an antibacterial biomaterial. For this purpose, calcium-alginate beads were formed by dropping to calcium-chloride solution and tetracycline was immobilized to beads using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide at optimum conditions. After immobilization, actualization of immobilization was investigated by analyzing ATR-FTIR spectrum and SEM images. Also, antibacterial property of obtained product was tested. Improved product demonstrated antibacterial property. It has potential for open wound, surgical drapes, bed and pillow sheath in hospitals and it may also be used for increasing human comfort in daily life. PMID:27474587

  1. Kinetic analysis of dihydroxyacetone production from crude glycerol by immobilized cells of Gluconobacter oxydans MTCC 904.

    PubMed

    Dikshit, Pritam Kumar; Moholkar, Vijayanand S

    2016-09-01

    The present study has investigated kinetic features of bioconversion of biodiesel-derived crude glycerol to dihydroxyacetone with immobilized Gluconobacter oxydans cells using modified Haldane substrate-inhibition model. The results have been compared against free cells and pure glycerol. Relative variations in the kinetic parameters KS, KI, Vmax, n and X reveal that immobilized G. oxydans cells (on PU foam substrate) with crude glycerol as substrate give higher order of inhibition (n) and lower maximum reaction velocities (Vmax). These results are essentially implications of substrate transport restrictions across immobilization matrix, which causes retention of substrate in the matrix and reduction in fractional available substrate (X) for the cells. This causes reduction in both KS (substrate concentration at Vmax/2) and KI (inhibition constant) as compared to free cells. For immobilized cells, substrate concentration (Smax) corresponding to Vmax is practically same for both pure and crude glycerol as substrate. PMID:27343447

  2. Substitution of carbonate buffer by water for IgG immobilization in enzyme linked immunosorbent assay.

    PubMed

    Shrivastav, Tulsidas G; Basu, Anupam; Kariya, Kiran P

    2003-01-01

    The first step of enzyme linked immunosorbent assay (ELISA), namely, adsorption of antigen or antibody to the plastic microtiter well plate, was studied as a function of insolubility of IgG in water. Immobilization efficiency was assessed in terms of number of wells coated per milliliter of primary antiserum. We have compared different coating/immobilization protocols, i.e., direct and indirect immobilization of primary antibody to the plastic microtiter well plate using carbonate buffer and phosphate buffer with glutaraldehyde. We have observed efficient coating when the immobilization of primary antibody through an immunobridge technique was performed, where water was used as a coating medium. It gave a higher number of wells coated per milliliter of anti-serum (primary or secondary) than other compared coating protocols and it allowed the use of serum (non-immune) and anti-serum (primary and secondary antibody) dilutions, avoiding the need for gamma-globulin purification from normal and immunized serum. PMID:12778971

  3. Surface immobilization of kanamycin-chitosan nanoparticles on polyurethane ureteral stents to prevent bacterial adhesion.

    PubMed

    Venkat Kumar, Govindarajan; Su, Chia-Hung; Velusamy, Palaniyandi

    2016-09-13

    Bacterial adhesion is a major problem that can lead to the infection of implanted urological stents. In this study, kanamycin-chitosan nanoparticles (KMCSNPs) were immobilized on the surface of a polyurethane ureteral stent (PUS) to prevent urinary bacterial infection. KMCSNPs were synthesized using the ionic gelation method. The synthesized KMCSNPs appeared spherical with a ζ-average particle size of 225 nm. KMCSNPs were immobilized on the PUS surface by covalent immobilization techniques. The surface-modified PUS was characterized using attenuated total reflectance Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. The surface-modified PUS showed significantly increased antibacterial activity against Escherichia coli MTCC 729 and Proteus mirabilis MTCC 425 relative to the surface of an unmodified PUS. These findings suggest that the KMCSNP-immobilized PUS has the potential to prevent bacterial infection in the human urinary tract. PMID:27436679

  4. A radioimmunoassay method for detection of DNA based on chemical immobilization of anti-DNA antibody.

    PubMed

    Yoo, S K; Yoon, M; Park, U J; Han, H S; Kim, J H; Hwang, H J

    1999-09-30

    High selectivity provided by biomolecules such as antibodies and enzymes has been exploited during the last two decades for development of biosensors. Of particular importance are efficient immobilization methods for biomolecules in order to preserve their biological activities. In this study, we have evaluated immobilization strategies for an anti-DNA antibody on a self-assembled monolayer of omega-functionalized thiols. The antibody was immobilized via peptide bond formation between the primary amines in the antibody and the carboxyl groups on the self-assembled monolayer. The peptide bond coupling was achieved by activating COOH groups on the surface through N-Hydroxysuccimide (NHS)-ester formation, followed by acylation of NH2 group in the antibody. DNA binding activity of the immobilized antibody was examined by counting beta emission from 35S-labeled DNA. PMID:10551259

  5. Covalent immobilization of protein onto a functionalized hydrogenated diamond-like carbon substrate.

    PubMed

    Biswas, Hari Shankar; Datta, Jagannath; Chowdhury, D P; Reddy, A V R; Ghosh, Uday Chand; Srivastava, Arvind Kumar; Ray, Nihar Ranjan

    2010-11-16

    Hydrogenated diamond-like carbon (HDLC) has an atomically smooth surface that can be deposited on high-surface area substrata and functionalized with reactive chemical groups, providing an ideal substrate for protein immobilization. A synthetic sequence is described involving deposition and hydrogenation of DLC followed by chemical functionalization. These functional groups are reacted with amines on proteins causing covalent immobilization on contact. Raman measurements confirm the presence of these surface functional groups, and Fourier transform infrared spectroscopy (FTIR) confirms covalent protein immobilization. Atomic force microscopy (AFM) of immobilized proteins is reproducible because proteins do not move as a result of interactions with the AFM probe-tip, thus providing an advantage over mica substrata typically used in AFM studies of protein. HDLC offers many of the same technical advantages as oxidized graphene but also allows for coating large surface areas of biomaterials relevant to the fabrication of medical/biosensor devices. PMID:20949913

  6. Immobilization of a Pleurotus ostreatus laccase mixture on perlite and its application to dye decolourisation.

    PubMed

    Pezzella, Cinzia; Russo, Maria Elena; Marzocchella, Antonio; Salatino, Piero; Sannia, Giovanni

    2014-01-01

    In the present study, a crude laccase preparation from Pleurotus ostreatus was successfully immobilized on perlite, a cheap porous silica material, and tested for Remazol Brilliant Blue R (RBBR) decolourisation in a fluidized bed recycle reactor. Results showed that RBBR decolourisation is mainly due to enzyme action despite the occurrence of dye adsorption-related enzyme inhibition. Fine tuning of immobilization conditions allowed balancing the immobilization yield and the resulting rate of decolourisation, with the adsorption capacity of the solid biocatalyst. In the continuous lab scale reactor, a maximum conversion degree of 56.1% was achieved at reactor space-time of 4.2 h. Stability and catalytic parameters of the immobilized laccases were also assessed in comparison with the soluble counterparts, revealing an increase in stability, despite a reduction of the catalytic performances. Both effects are most likely ascribable to the occurrence of multipoint attachment phenomena. PMID:24895564

  7. Developing an Efficient and General Strategy for Immobilization of Small Molecules onto Microarrays Using Isocyanate Chemistry.

    PubMed

    Zhu, Chenggang; Zhu, Xiangdong; Landry, James P; Cui, Zhaomeng; Li, Quanfu; Dang, Yongjun; Mi, Lan; Zheng, Fengyun; Fei, Yiyan

    2016-01-01

    Small-molecule microarray (SMM) is an effective platform for identifying lead compounds from large collections of small molecules in drug discovery, and efficient immobilization of molecular compounds is a pre-requisite for the success of such a platform. On an isocyanate functionalized surface, we studied the dependence of immobilization efficiency on chemical residues on molecular compounds, terminal residues on isocyanate functionalized surface, lengths of spacer molecules, and post-printing treatment conditions, and we identified a set of optimized conditions that enable us to immobilize small molecules with significantly improved efficiencies, particularly for those molecules with carboxylic acid residues that are known to have low isocyanate reactivity. We fabricated microarrays of 3375 bioactive compounds on isocyanate functionalized glass slides under these optimized conditions and confirmed that immobilization percentage is over 73%. PMID:26999137

  8. Synthesis, spectroscopic and catalytic studies of Cu(II), Co(II) and Ni(II) complexes immobilized on Schiff base modified chitosan

    NASA Astrophysics Data System (ADS)

    Antony, R.; Theodore David Manickam, S.; Saravanan, K.; Karuppasamy, K.; Balakumar, S.

    2013-10-01

    A new class of bidentate (N, O) Schiff base ligand (L) has been derived from the functional biopolymer (chitosan) and 1,2-diphenylethanedione in 1:1 M ratio. This ligand has been used to synthesise the new first row transition metal complexes of Cu(II), Co(II) and Ni(II). The structural properties of the ligand and the synthesized tetra-coordinated complexes have been investigated by elemental analysis, magnetic study, molar conductance measurement and spectroscopic methods viz. FT-IR, UV-Vis., 1H NMR, 13C NMR and XRD. The spectral evidences strongly suggested the square planar geometry to the complexes. The XRD studies proved that crystallinity of chitosan has been diminished after Schiff base formation and metal complexation of L. Thermal and surface properties of the complexes have been also discussed from the investigation of their TG-DTG curves and SEM images, respectively. In addition, the catalytic efficiency of these complexes has been studied in the cyclohexane oxidation reaction using H2O2 as oxidant at 70 °C.

  9. Immobilization of lipase onto micron-size magnetic beads.

    PubMed

    Liu, Xianqiao; Guan, Yueping; Shen, Rui; Liu, Huizhou

    2005-08-01

    A novel and economical magnetic poly(methacrylate-divinylbenzene) microsphere (less than 8 microm in diameter) was synthesized by the modified suspension polymerization of methacrylate and cross-linker divinylbenzene in the presence of magnetic fluid. Then, surface aminolysis was employed to obtain a high content of surface amino groups (0.40-0.55 mmolg(-1) supports). The morphology and properties of these magnetic supports were characterized with scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy and a vibrating sample magnetometer. These magnetic supports exhibited superparamagnetism with a high specific saturation magnetization (sigma(s)) of 14.6 emicrog(-1). Candida cylindracea lipase was covalently immobilized on the amino-functionalized magnetic supports with the activity recovery up to 72.4% and enzyme loading of 34.0 mgg(-1) support, remarkably higher than the previous studies. The factors involved in the activity recovery and enzymatic properties of the immobilized lipase prepared were studied in comparison with free lipase, for which olive oil was chosen as the substrate. The results show that the immobilized lipase has good stability and reusability after recovery by magnetic separation within 20s. PMID:15998604

  10. [The combined action of drinking mineral water and low-intensity electromagnetic radiation under the immobilization stress conditions (an experimental study)].

    PubMed

    Korolev, Yu N; Bobrovnitsky, I P; Geniatulina, M S; Mikhailik, L V; Nikulina, L A; Bobkova, A S; Yakovlev, M Yu

    2015-01-01

    The present study carried out on white male rats in experiments with the use of biochemical, radioimmunological, and electron- microscopic methods. It was shown that the combined treatment with potable mineral water (MV) and low-intensity electromagnetic radiation (LIEMR) of ultrahigh frequency (power density less than 1 pW/cm2, the frequency about 1000 MHz) facilitated the activation of metabolic and intracellular regenerative processes in the liver and testes. One of the advantages of the combined application of MV and LIEMR over the single-factor treatment manifested itself as the weakening of stress reactions, the increase in the frequency of the plastic processes, and the more harmonious development of different forms of intracellular regeneration. The results of the study provide a deeper insight ino the mechanisms underlying the combined actions of drinking mineral water and low-intensity electromagnetic radiation; also, they justify the application of these factors for the protection of the reproductive system and the entire body from stress-induced disorders. PMID:26841527

  11. A Biomechanical Comparison of Intralaminar C7 Screw Constructs with and without Offset Connector Used for C6-7 Cervical Spine Immobilization : A Finite Element Study

    PubMed Central

    Qasim, Muhammad; Natarajan, Raghu N.; An, Howard S.

    2013-01-01

    Objective The offset connector can allow medial and lateral variability and facilitate intralaminar screw incorporation into the construct. The aim of this study was to compare the biomechanical characteristics of C7 intralaminar screw constructs with and without offset connector using a three dimensional finite element model of a C6-7 cervical spine segment. Methods Finite element models representing C7 intralaminar screw constructs with and without the offset connector were developed. Range of motion (ROM) and maximum von Mises stresses in the vertebra for the two techniques were compared under pure moments in flexion, extension, lateral bending and axial rotation. Results ROM for intralaminar screw construct with offset connector was less than the construct without the offset connector in the three principal directions. The maximum von Misses stress was observed in the C7 vertebra around the pedicle in both constructs. Maximum von Mises stress in the construct without offset connector was found to be 12-30% higher than the corresponding stresses in the construct with offset connector in the three principal directions. Conclusion This study demonstrated that the intralaminar screw fixation with offset connector is better than the construct without offset connector in terms of biomechanical stability. Construct with the offset connector reduces the ROM of C6-7 segment more significantly compared to the construct without the offset connector and causes lower stresses around the C7 pedicle-vertebral body complex. PMID:24003366

  12. Influence of protein bulk properties on membrane surface coverage during immobilization.

    PubMed

    Militano, Francesca; Poerio, Teresa; Mazzei, Rosalinda; Piacentini, Emma; Gugliuzza, Annarosa; Giorno, Lidietta

    2016-07-01

    Biomolecules immobilization is a key factor for many biotechnological applications. For this purpose, the covalent immobilization of bovine serum albumin (BSA), lipase from Candida rugosa and protein G on differently functionalized regenerated cellulose membranes was investigated. Dynamic light scattering and electrophoresis measurements carried out on biomolecules in solution indicated the presence of monomers, dimers and trimers for both BSA and protein G, while large aggregates were observed for lipase. The immobilization rate and the surface coverage on functionalized regenerated cellulose membranes were studied as a function of biomolecule concentration. Results indicated that the saturation coverage of BSA and protein G was concentration independent (immobilized protein amount of 2.40±0.03mg/g and 2.65±0.07mg/g, respectively). Otherwise, a different immobilization kinetics trend was obtained for lipase, for which the immobilized amount increases as a function of time without reaching a saturation value. Atomic force microscopy (AFM) micrographs showed the formation of monolayers for both BSA and protein G on the membrane surface, while a multilayer structure is found for lipase, in agreement with the trends observed in the related immobilization kinetics. As a result, the morphology of the proteins layer on the membrane surface seems to be strictly dependent on the proteins behavior in solution. Besides, the surface coverage has been described for BSA and protein G by the pseudo second order models, the results indicating the surface reaction as the controlling step of immobilization kinetics. Finally, enzyme activity and binding capacity studies indicated the preservation of the biomolecule functional properties. PMID:27022871

  13. A Biomechanical Comparison of Three Different Posterior Fixation Constructs Used for C6–C7 Cervical Spine Immobilization: A Finite Element Study

    PubMed Central

    HONG, Jae Taek; QASIM, Muhammad; ESPINOZA ORÍAS, Alejandro A.; NATARAJAN, Raghu N.; AN, Howard S.

    2014-01-01

    The intralaminar screw construct has been recently introduced in C6–C7 fixation. The aim of the study is to compare the stability afforded by three different C7 posterior fixation techniques using a three-dimensional finite element model of a C6–C7 cervical spine motion segment. Finite element models representing three different cervical anchor types (C7 intralaminar screw, C7 lateral mass screw, and C7 pedicle screw) were developed. Range of motion (ROM) and maximum von Mises stresses in the vertebra for the three screw techniques were compared under pure moments in flexion, extension, lateral bending, and axial rotation. ROM for pedicle screw construct was less than the lateral mass screw construct and intralaminar screw construct in the three principal directions. The maximum von Misses stress was observed in the C7 vertebra around the pedicle in all the three screw constructs. Maximum von Mises stress in pedicle screw construct was less than the lateral mass screw construct and intralaminar screw construct in all loading modes. This study demonstrated that the pedicle screw fixation is the strongest instrumentation method for C6–C7 fixation. Pedicle screw fixation resulted in least stresses around the C7 pedicle-vertebral body complex. However, if pedicle fixation is not favorable, the laminar screw can be a better option compared to the lateral mass screw because the stress around the pedicle-vertebral body complex and ROM predicted for laminar screw construct was smaller than those of lateral mass screw construct. PMID:24418790

  14. Cortical Reorganization after Hand Immobilization: The beta qEEG Spectral Coherence Evidences

    PubMed Central

    Fortuna, Marina; Teixeira, Silmar; Machado, Sérgio; Velasques, Bruna; Bittencourt, Juliana; Peressutti, Caroline; Budde, Henning; Cagy, Mauricio; Nardi, Antonio E.; Piedade, Roberto; Ribeiro, Pedro; Arias-Carrión, Oscar

    2013-01-01

    There is increasing evidence that hand immobilization is associated with various changes in the brain. Indeed, beta band coherence is strongly related to motor act and sensitive stimuli. In this study we investigate the electrophysiological and cortical changes that occur when subjects are submitted to hand immobilization. We hypothesized that beta coherence oscillations act as a mechanism underlying inter- and intra-hemispheric changes. As a methodology for our study fifteen healthy individuals between the ages of 20 and 30 years were subjected to a right index finger task before and after hand immobilization while their brain activity pattern was recorded using quantitative electroencephalography. This analysis revealed that hand immobilization caused changes in frontal, central and parietal areas of the brain. The main findings showed a lower beta-2 band in frontal regions and greater cortical activity in central and parietal areas. In summary, the coherence increased in the frontal, central and parietal cortex, due to hand immobilization and it adjusted the brains functioning, which had been disrupted by the procedure. Moreover, the brain adaptation upon hand immobilization of the subjects involved inter- and intra-hemispheric changes. PMID:24278213

  15. “Fish-in-Net”, a Novel Method for Cell Immobilization of Zymomonas mobilis

    PubMed Central

    Niu, Xuedun; Wang, Zhi; Li, Yang; Zhao, Zijian; Liu, Jiayin; Jiang, Li; Xu, Haoran; Li, Zhengqiang

    2013-01-01

    Background Inorganic mesoporous materials exhibit good biocompatibility and hydrothermal stability for cell immobilization. However, it is difficult to encapsulate living cells under mild conditions, and new strategies for cell immobilization are needed. We designed a “fish-in-net” approach for encapsulation of enzymes in ordered mesoporous silica under mild conditions. The main objective of this study is to demonstrate the potential of this approach in immobilization of living cells. Methodology/Principal Findings Zymomonas mobilis cells were encapsulated in mesoporous silica-based materials under mild conditions by using a “fish-in-net” approach. During the encapsulation process, polyethyleneglycol was used as an additive to improve the immobilization efficiency. After encapsulation, the pore size, morphology and other features were characterized by various methods, including scanning electron microscopy, nitrogen adsorption-desorption analysis, transmission electron microscopy, fourier transform infrared spectroscopy, and elemental analysis. Furthermore, the capacity of ethanol production by immobilized Zymomonas mobilis and free Zymomonas mobilis was compared. Conclusions/Significance In this study, Zymomonas mobilis cells were successfully encapsulated in mesoporous silica-based materials under mild conditions by the “fish-in-net” approach. Encapsulated cells could perform normal metabolism and exhibited excellent reusability. The results presented here illustrate the enormous potential of the “fish-in-net” approach for immobilization of living cells. PMID:24236145

  16. Physiological tests for yeast brewery cells immobilized on modified chamotte carrier.

    PubMed

    Berlowska, Joanna; Kregiel, Dorota; Ambroziak, Wojciech

    2013-11-01

    In this study yeast cell physiological activity was assessed on the basis of the in situ activity of two important enzymes, succinate dehydrogenase and pyruvate decarboxylase. FUN1 dye bioconversion and cellular ATP content were also taken as important indicators of yeast cell activity. The study was conducted on six brewing yeast strains, which were either free cells or immobilized on a chamotte carrier. The experimental data obtained indicate clearly that, in most cases, the immobilized cells showed lower enzyme activity than free cells from analogous cultures. Pyruvate decarboxylase activity in immobilized cells was higher than in planktonic cell populations only in the case of the Saccharomyces pastorianus 680 strain. However, in a comparative assessment of the fermentation process, conducted with the use of free and immobilized cells, much more favorable dynamics and carbon dioxide productivity were observed in immobilized cells, especially in the case of brewing lager yeast strains. This may explain the higher total cell density per volume unit of the fermented medium and the improved resistance of immobilized cells to environmental changes. PMID:23887884

  17. Bioinspired Immobilization of Glycerol Dehydrogenase by Metal Ion-Chelated Polyethyleneimines as Artificial Polypeptides

    PubMed Central

    Zhang, Yonghui; Ren, Hong; Wang, Yali; Chen, Kainan; Fang, Baishan; Wang, Shizhen

    2016-01-01

    In this study, a novel, simple and generally applicable strategy for multimeric oxidoreductase immobilization with multi-levels interactions was developed and involved activity and stability enhancements. Linear polyethyleneimines (PEIs) are flexible cationic polymers with molecular weights that span a wide range and are suitable biomimic polypeptides for biocompatible frameworks for enzyme immobilization. Metal ion-chelated linear PEIs were applied as a heterofunctional framework for glycerol dehydrogenase (GDH) immobilization by hydrogen bonds, electrostatic forces and coordination bonds interactions. Nanoparticles with diameters from 250–650 nm were prepared that exhibited a 1.4-fold enhancement catalytic efficiency. Importantly, the half-life of the immobilized GDH was enhanced by 5.6-folds in aqueous phase at 85 °C. A mechanistic illustration of the formation of multi-level interactions in the PEI-metal-GDH complex was proposed based on morphological and functional studies of the immobilized enzyme. This generally applicable strategy offers a potential technique for multimeric enzyme immobilization with the advantages of low cost, easy operation, high activity reservation and high stability. PMID:27053034

  18. Immobilization of thermolysin to polyamide nonwoven materials.

    PubMed

    Moeschel, Klaus; Nouaimi, Meryem; Steinbrenner, Christa; Bisswanger, Hans

    2003-04-20

    In the last few years, an increasing number of biotechnological techniques have been applied to the restoration and conservation of works of art, paintings, old maps, and papers or books. Enzymes can solve problems that give restorers difficulties, although for many applications it is not possible to use soluble enzymes; therefore, it is necessary to look for suitable carriers for immobilization. Different methods for covalent immobilization of enzymes to polyamide nonwovens were tested, using thermolysin as an example. Two distinct strategies were pursued: (1). controlled, partial hydrolysis of the polymer and subsequent binding of the enzyme to the released amino and carboxy groups; and (2). attachment of reactive groups directly to the polyamide without disintegrating the polymeric structure (O-alkylation). Different spacers were used for covalent fixation of the enzyme in both cases. The enzyme was fixed to the released amino groups by glutaraldehyde, either with or without a spacer. Either way, active enzyme could be immobilized to the matrix. However, intense treatment caused severe damage to the stability of the nonwoven fabric, and reduced the mechanical strength. Conditions were investigated to conserve the nonwoven fabric structure while obtaining near-maximum immobilized enzyme activity. Immobilization of the enzyme to the released carboxy group after acid hydrolysis was performed using dicyclohexylcarbodiimide. In comparison to the enzyme bound via the amino group, the yield of immobilized enzyme activity was slightly lower when benzidine was taken as spacer and still lower with a 1,6-hexanediamine spacer. O-alkylation performed with dimethylsulfate caused severe damage to the nonwoven fabric structure. Considerably better results were obtained with triethyloxonium tetrafluoroborate. As the spacers 1,6-hexanediamine and adipic acid dihydrazide were used, activation for immobilizing thermolysin was performed with glutaraldehyde, adipimidate, and azide

  19. Effects of joint immobilization on standing balance.

    PubMed

    de Freitas, Paulo B; Freitas, Sandra M S F; Duarte, Marcos; Latash, Mark L; Zatsiorsky, Vladimir M

    2009-08-01

    We investigated the effect of joint immobilization on the postural sway during quiet standing. We hypothesized that the center of pressure (COP), rambling, and trembling trajectories would be affected by joint immobilization. Ten young adults stood on a force plate during 60 s without and with immobilized joints (only knees constrained, CK; knees and hips, CH; and knees, hips, and trunk, CT), with their eyes open (OE) or closed (CE). The root mean square deviation (RMS, the standard deviation from the mean) and mean speed of COP, rambling, and trembling trajectories in the anterior-posterior and medial-lateral directions were analyzed. Similar effects of vision were observed for both directions: larger amplitudes for all variables were observed in the CE condition. In the anterior-posterior direction, postural sway increased only when the knees, hips, and trunk were immobilized. For the medial-lateral direction, the RMS and the mean speed of the COP, rambling, and trembling displacements decreased after immobilization of knees and hips and knees, hips, and trunk. These findings indicate that the single inverted pendulum model is unable to completely explain the processes involved in the control of the quiet upright stance in the anterior-posterior and medial-lateral directions. PMID:19342114

  20. EFFECTS OF JOINT IMMOBILIZATION ON STANDING BALANCE

    PubMed Central

    de Freitas, Paulo B.; Freitas, Sandra M. S. F.; Duarte, Marcos; Latash, Mark L.; Zatsiorsky, Vladimir M.

    2009-01-01

    We investigated the effect of joint immobilization on the postural sway during quiet standing. We hypothesized that center of pressure (COP), rambling, and trembling trajectories could be affected by joint immobilization. Ten young adults stood on a force plate during 60 s without and with immobilized joints (only knees constrained, CK; knees and hips, CH; and knees, hips and trunk, CT), with their eyes opened (EO) or closed (EC). The root mean square deviation (RMS, the standard deviation from the mean) and mean speed of COP, rambling, and trembling trajectories in the anterior-posterior and medial-lateral directions were analyzed. Similar effects of vision were observed for both directions: larger amplitude for all variables was observed in the EC condition. In the anterior-posterior direction, postural sway increased only when the knees, hips and trunk were immobilized. For the medial-lateral direction, the RMS and the mean speed of the COP, rambling, and trembling displacements decreased after immobilization of knees and hips and knees, hips and trunk. These findings indicate that the inverted pendulum model is unable to completely explain the processes involved in the control of the quiet upright stance in the anterior-posterior and medial-lateral directions. PMID:19342114

  1. Accumulation of uranium by immobilized persimmon tannin

    SciTech Connect

    Sakaguchi, Takashi; Nakajima, Akira )

    1994-01-01

    We have discovered that the extracted juice of unripe astringent persimmon fruit, designated as kakishibu or shibuol, has an extremely high affinity for uranium. To develop efficient adsorbents for uranium, we tried to immobilize kakishibu (persimmon tannin) with various aldehydes and mineral acids. Persimmon tannin immobilized with glutaraldehyde can accumulate 1.71 g (14 mEq U) of uranium per gram of the adsorbent. The uranium accumulating capacity of this adsorbent is several times greater than that of commercially available chelating resins (2-3 mEq/g). Immobilized persimmon tannin has the most favorable features for uranium recovery; high selective adsorption ability, rapid adsorption rate, and applicability in both column and batch systems. The uranium retained on immobilized persimmon tannin can be quantitatively and easily eluted with a very dilute acid, and the adsorbent can thus be easily recycled in the adsorption-desorption process. Immobilized persimmon tannin also has a high affinity for thorium. 23 refs., 13 figs., 7 tabs.

  2. Catalysis of Rice Straw Hydrolysis by the Combination of Immobilized Cellulase from Aspergillus niger on β-Cyclodextrin-Fe3O4 Nanoparticles and Ionic Liquid

    PubMed Central

    Huang, Po-Jung; Chang, Ken-Lin; Chen, Shui-Tein

    2015-01-01

    Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11 U g immobilized cellulase−1 at an ionic liquid concentration of 200 mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739 g h−1 L−1. One of the advantages of immobilized cellulase is high reusability—it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15 g L−1). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase. PMID:25874210

  3. Cellobiose hydrolysis using Pichia etchellsii cells immobilized in calcium alginate

    SciTech Connect

    Jain, D.; Ghose, T.K.

    1984-01-01

    The rate of cellulose degradation, limited by inhibition by cellobiose, can be increased by hydrolysis of cellobiose to glucose using immobilized ..beta..-glucosidase. Production of ..beta..-glucosidase in four yeasts was studied and a maximum activity of 1.22 IU/mg cells was obtained in cells of Pichia etchellsii when grown on 3% cellobiose as the sole carbon source. Immobilization of ..beta..-glucosidase containing cells of Pichia etchellsii on various solid supports was conducted and immobilization by entrapment in calcium alginate gel beads was found to be the most simple and efficient method. The immobilized preparation was found to be limited by pore diffusion but exhibited no film-diffusion resistance during packed bed reactor operation. Good plug flow characteristics were observed in the packed bed column indicated by a low dispersion number of 0.1348. A model for reaction with pore diffusion for a noncompetitive type of inhibited system was developed and applied to the cellobiose hydrolysis system. The rate of reaction with diffusional limitations was determined by using the model and effectiveness factors were calculated for different particle sizes. An effectiveness factor of 0.49 was obtained for a particle diameter of 2.5 mm. The modified rate expression using the effectiveness factor represented batch and packed bed reactor operation satisfactorily. The productivity in the packed bed column was found to fall rapidly with increase in conversion rate indicating that the operating conditions of the column would have to be a compromise between high conversion rates and reasonable productivity. A half-life of over seven days was obtained at the operating temperature of 45/sup 0/C in continuous operation of the packed bed reactor. However, the half-life in the column was found to be greatly affected by temperature, increasing to over seve

  4. Airline Chair-rest Deconditioning: Induction of Immobilization Thromboemboli?

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Rehrer, N. J.; Mohler, S. R.; Quach, D. T.; Evans, D. G.; Dalton, Bonnie P. (Technical Monitor)

    2002-01-01

    Air passenger miles will likely double by year 2020. The altered and restrictive environment in an airliner cabin can influence hematological homeostasis in passengers and crew. Flight-related deep various thromboemboli (DVT) have been associated with at least 577 deaths on 42 of 120 airlines from 1977 to 1984 (25 deaths/million departures), whereas many such cases go unreported. However, there are four major factors that could influence formation of possible flight-induced DVT: sleeping accomodations (via sitting immobilization), travelers' medical history (via tissue injury), cabin environmental factors (via lower partial pressure of oxygen and lower relative humidity), and the more encompassing chair-rest deconditioning (C-RD) syndrome. There is ample evidence that recent injury and surgery (especially in deconditioned hospitalized patients) facilitate thrombophlebitis and formation of DVT that may be exacerbated by the immobilization of prolonged air travel. In the healthy flying population immobilization factors associated with prolonged (> 5 hr) C-RID such as total body dehydration, hypovolemia and increased blood viscosity, and reduced various blood flow (pooling) in the legs may facilitate formation of DVT. However, data from at least four case-controlled epidemiological studies did not confirm a direct causative relationship between air travel and DART, but factors such as history of vascular thromboemboli, various insufficiency, chronic heart failure, obesity, immobile standing position, more than 3 pregnancies, infectious disease, long-distance travel, muscular trauma and violent physical effort were significantly more frequent in DVT patients than in controls. Thus, there is no clear, direct evidence yet that prolonged sitting in airliner seats, or prolonged experimental chair-rest- or bed- rest-deconditioning treatments cause deep various thromboemboli in healthy people.

  5. Immobilized Bioluminescent Reagents in Flow Injection Analysis.

    NASA Astrophysics Data System (ADS)

    Nabi, Abdul

    Available from UMI in association with The British Library. Bioluminescent reactions exhibits two important characteristics from an analytical viewpoint; they are selective and highly sensitive. Furthermore, bioluminescent emissions are easily measured with a simple flow-through detector based on a photomultiplier tube and the rapid and reproducible mixing of sample and expensive reagent is best achieved by a flow injection manifold. The two most important bioluminescent systems are the enzyme (luciferase)/substrate (luciferin) combinations extracted from fireflies (Photinus pyralis) and marine bacteria (Virio harveyi) which requires ATP and NAD(P)H respectively as cofactors. Reactions that generate or consume these cofactors can also be coupled to the bioluminescent reaction to provide assays for a wide range of clinically important species. A flow injection manifold for the study of bioluminescent reactions is described, as are procedures for the extraction, purification and immobilization of firefly and bacterial luciferase and oxidoreductase. Results are presented for the determination of ATP using firefly system and the determination of other enzymes and substrates participating in ATP-converting reactions e.g. creatine kinase, ATP-sulphurylase, pyruvate kinase, creatine phosphate, pyrophosphate and phophoenolypyruvate. Similarly results are presented for the determination of NAD(P)H, FMN, FMNH_2 and several dehydrogenases which produce NAD(P)H and their substrates, e.g. alcohol, L-lactate, L-malate, L-glutamate, Glucose-6-phosphate and primary bile acid.

  6. Potential Applications of Carbohydrases Immobilization in the Food Industry

    PubMed Central

    Contesini, Fabiano Jares; de Alencar Figueira, Joelise; Kawaguti, Haroldo Yukio; de Barros Fernandes, Pedro Carlos; de Oliveira Carvalho, Patrícia; Nascimento, Maria da Graça; Sato, Hélia Harumi

    2013-01-01

    Carbohydrases find a wide application in industrial processes and products, mainly in the food industry. With these enzymes, it is possible to obtain different types of sugar syrups (viz. glucose, fructose and inverted sugar syrups), prebiotics (viz. galactooligossacharides and fructooligossacharides) and isomaltulose, which is an interesting sweetener substitute for sucrose to improve the sensory properties of juices and wines and to reduce lactose in milk. The most important carbohydrases to accomplish these goals are of microbial origin and include amylases (α-amylases and glucoamylases), invertases, inulinases, galactosidases, glucosidases, fructosyltransferases, pectinases and glucosyltransferases. Yet, for all these processes to be cost-effective for industrial application, a very efficient, simple and cheap immobilization technique is required. Immobilization techniques can involve adsorption, entrapment or covalent bonding of the enzyme into an insoluble support, or carrier-free methods, usually based on the formation of cross-linked enzyme aggregates (CLEAs). They include a broad variety of supports, such as magnetic materials, gums, gels, synthetic polymers and ionic resins. All these techniques present advantages and disadvantages and several parameters must be considered. In this work, the most recent and important studies on the immobilization of carbohydrases with potential application in the food industry are reviewed. PMID:23344046

  7. Immobilization of heavy metals and phenol on altered bituminous coals

    SciTech Connect

    Taraba, B.; Marsalek, R.

    2007-07-01

    This article evaluates adsorption ability of the altered bituminous coals to remove heavy metals and/or phenol from aqueous solutions. As for heavy metals, copper (II), cadmium (II) and lead (II) cations were used. In addition to phenol, cyclohexanol and 2-cyclohexen-1-ol were also examined. Adsorption experiments were conducted in the batch mode at room temperature and at pH 3 and 5. To characterize the texture of coal samples, adsorption isotherms of nitrogen at - 196{sup o}C, enthalpies of the immersion in water, and pH values in aqueous dispersions were measured. Coal hydrogen aromaticities were evaluated from the infrared spectrometric examinations (DRIFTS). Based on the investigations performed, cation exchange was confirmed as the principal mechanism to immobilize heavy metallic ions on coals. However, apart from carboxylic groups, other functionalities (hydroxyl groups) were found to be involved in the adsorption process. During adsorption of phenol, {pi}-{pi} interactions between {pi}-electrons of phenol and aromatic rings of coal proved to play the important role; however, no distinct correlation between adsorption capacities for phenol and hydrogen aromaticities of the coal was found. Probable involvement of oxygenated surface groups in the immobilization of phenol on coal was deduced. As a result, for waste water treatment, oxidative altered bituminous coal can be recommended as a suitable precursor, with the largest immobilization capacities both for metallic ions and phenol, as found in the studied samples.

  8. Immobilized rennin in TC/SG composite in cheese production.

    PubMed

    Barouni, Eleftheria; Petsi, Theano; Kolliopoulos, Dionysios; Vasileiou, Dimitrios; Panas, Panagiotis; Bekatorou, Argyro; Kanellaki, Maria; Koutinas, Athanasios A

    2016-06-01

    The object of the current study was to develop a new process for continuous Feta-type cheese production using a biocatalyst consisting of immobilized rennin on a tubular cellulose/starch gel (TC/SG) composite, which has been proven to be an appropriate carrier for enzyme immobilization. Different methodologies were used in order to prepare four biocatalysts. The most effective was selected for cheese production in a 1L continuous system, providing two economically useful results for the dairy industries: (i) increase of productivity by the continuous coagulation of milk, and (ii) saving of the rennin enzyme expenses of the batch coagulation of milk. The criteria used to choose the appropriate biocatalyst was based on the time of coagulation in successive batches, the concentration of immobilized rennin combined with the filter efficiency and its application in the continuous system. Physicochemical analyses of the cheeses at various stages of the ripening were performed. No significant differences compared to cheeses prepared with the traditional method were found. Aroma compounds were determined by SPME GC-MS. PMID:26830563

  9. Protein synthesis rates in atrophied gastrocnemius muscles after limb immobilization

    NASA Technical Reports Server (NTRS)

    Tucker, K. R.; Seider, M. J.; Booth, F. W.

    1981-01-01

    Noting that protein synthesis declines in the gastrocnemius 6 hr after immobilization, the study sought to detect an increase of protein synthesis when the limb was freed, and to examine the effects of exercise on the rate of increase. Rats were used as subjects, with their hind legs in plaster of Paris in plantar flexion to eliminate strain on the gastrocnemius. Periods of immobilization were varied and samples of blood from the muscle were taken to track protein synthesis rates for different groups in immobilization and exercise regimens (running and weightlifting). Synthesis rates declined 3.6% during time in the cast, then increased 6.3%/day after the casts were removed. Both running and weightlifting were found to increase the fractional rate of protein formation in the gastrocnemius muscle when compared with contralateral muscles that were not exercised and were used as controls, suggesting that the mechanism controlling protein synthesis in skeletal muscles is rapidly responsive to changes in muscular contractile activity.

  10. In vivo immobilization of D-hydantoinase in Escherichia coli.

    PubMed

    Chen, Shan-Yu; Chien, Yi-Wen; Chao, Yun-Peng

    2014-07-01

    D-P-Hydroxyphenylglycine (D-HPG) is a precursor required for the synthesis of semi-synthetic antibiotics. This unnatural amino acid can be produced by a transformation reaction mediated by D-hydantoinase (D-HDT) and d-amidohydrolase. In this study, a method was developed to integrate production and immobilization of recombinant D-HDT in vivo. This was approached by first fusion of the gene encoding D-HDT with phaP (encoding phasin) of Ralstonia eutropha H16. The fusion gene was then expressed in the Escherichia coli strain that carried a heterologous synthetic pathway for polyhydroxyalkanoate (PHA). As a result, d-HDT was found to associate with isolated PHA granules. Further characterization illustrated that D-HDT immobilized on PHA exhibited the maximum activity at pH 9 and 60°C and had a half-life of 95 h at 40°C. Moreover, PHA-bound d-HDT could be reused for 8 times with the conversion yield exceeding 90%. Overall, it illustrates the feasibility of this approach to facilitate in vivo immobilization of enzymes in heterologous E. coli strain, which may open a new avenue of enzyme application in industry. PMID:24508023

  11. Potential applications of carbohydrases immobilization in the food industry.

    PubMed

    Contesini, Fabiano Jares; de Alencar Figueira, Joelise; Kawaguti, Haroldo Yukio; de Barros Fernandes, Pedro Carlos; de Oliveira Carvalho, Patrícia; da Graça Nascimento, Maria; Sato, Hélia Harumi

    2013-01-01

    Carbohydrases find a wide application in industrial processes and products, mainly in the food industry. With these enzymes, it is possible to obtain different types of sugar syrups (viz. glucose, fructose and inverted sugar syrups), prebiotics (viz. galactooligossacharides and fructooligossacharides) and isomaltulose, which is an interesting sweetener substitute for sucrose to improve the sensory properties of juices and wines and to reduce lactose in milk. The most important carbohydrases to accomplish these goals are of microbial origin and include amylases (α-amylases and glucoamylases), invertases, inulinases, galactosidases, glucosidases, fructosyltransferases, pectinases and glucosyltransferases. Yet, for all these processes to be cost-effective for industrial application, a very efficient, simple and cheap immobilization technique is required. Immobilization techniques can involve adsorption, entrapment or covalent bonding of the enzyme into an insoluble support, or carrier-free methods, usually based on the formation of cross-linked enzyme aggregates (CLEAs). They include a broad variety of supports, such as magnetic materials, gums, gels, synthetic polymers and ionic resins. All these techniques present advantages and disadvantages and several parameters must be considered. In this work, the most recent and important studies on the immobilization of carbohydrases with potential application in the food industry are reviewed. PMID:23344046

  12. pH dependent immobilization of Urease on glutathione capped gold nanoparticles.

    PubMed

    Garg, Seema; De, Arnab; Mozumdar, Subho

    2014-09-01

    Urease is a nickel-dependent metallonzyme that catalyzes the hydrolysis of urea to form ammonia and carbon dioxide. Although the enzyme serves a significant role in several detoxification and analytical processes, its usability is restricted due to high cost, availability in small amounts, instability and a limited possibility of economic recovery from a reaction mixture. Hence, there is a need to develop an efficient, simple and reliable immobilization strategy for the enzyme. In this work, the carboxyl terminated surface of glutathione capped gold nanoparticles have been utilized as a solid support for the covalent attachment of Urease. The immobilization has been carried out at different pH conditions so as to elucidate its effect on the immobilization efficiency and enzyme bio-activity. The binding of the enzyme has been quantitatively and qualitatively analyzed through techniques like UV-Vis spectroscopy, intrinsic steady state fluorescence and Circular Dichorism. The bio-activity of the immobilized enzyme was investigated with respect to the native enzyme under different thermal conditions. Recyclability and shelf life studies of the immobilized enzyme have also been carried out. Results reveal that the immobilization is most effective at pH of 7.4 followed by that in an acidic medium and is least in alkaline environment. The immobilized enzyme also exhibits enhance activity in comparison to the native form at physiological temperature. The immobilized urease (on gold glutathione nano-conjugates surface) can be effectively employed for biosensor fabrication, immunoassays and as an in vivo diagnostic tool in the future. PMID:25196908

  13. Immobilization and catalytic properties of candida lipolytic lipase on surface of organic intercalated and modified MgAl-LDHs

    NASA Astrophysics Data System (ADS)

    Dong, Lijun; Ge, Chunling; Qin, Peiyong; Chen, Yan; Xu, Qinghong

    2014-05-01

    In this study, MgAl-LDHs (layered double hydroxides) intercalated with sodium dodecyl sulfate and outside surface modified with (3-aminopropyl)triethoxysilane (KH550) were prepared. The existence of organic part in LDHs improved immobilization efficiency and activity recovery of candida lipolytic lipase loaded. Also the positive charge in framework of LDHs was found to be beneficial to the enzyme immobilization. An immobilization efficiency of 56.4% and an activity recovery over 69.2% of the enzyme were obtained after it was loaded on the intercalated and modified LDHs, and catalytic activity of the immobilization can be kept at least five times. Moreover, the immobilized enzyme was found to have higher temperature resistance, wider pH value and better thermostability in reactive activity.

  14. Layer-by-layer self-assembly immobilization of catalases on wool fabrics.

    PubMed

    Liu, J; Wang, Q; Fan, X R; Sun, X J; Huang, P H

    2013-04-01

    A new immobilization strategy of catalases on natural fibers was reported in this paper. Catalase (CAT) from Bacillus subtilis was assembled into multiple layers together with poly(diallyldimethylammonium chloride) (PDDA) on wool fabrics via layer-by-layer (LBL) electrostatic self-assembly deposition. The mechanism and structural evaluation of LBL electrostatic self-assembly were studied in terms of scanning electron microscopy (SEM), surface zeta potential, and apparent color depth (K/S). The SEM pictures showed obvious deposits absorbed on the wool surfaces after LBL self-assembly. The surface zeta potential and dyeing depth of CAT/PDDA-assembled wool fabrics presented a regular layer-by-layer alternating trend along with the change of deposited materials, revealing the multilayer structure of the wool fiber immobilized catalases. The V(max) values were found to be 2,500±238 U/mg protein for the free catalase and 1,000±102 U/mg protein for the immobilized catalase. The K(m) value of free catalase (11.25±2.3 mM) was found to be lower than that of the immobilized catalase (222.2±36.5 mM). The immobilized catalase remained high enzymatic activity and showed a measureable amount of reusability, which proved that LBL electrostatic self-assembly deposition is a promising approach to immobilize catalases. PMID:23420488

  15. Synergistic effects of amine and protein modified epoxy-support on immobilized lipase activity.

    PubMed

    Cui, Caixia; Tao, Yifeng; Ge, Chunling; Zhen, Yueju; Chen, Biqiang; Tan, Tianwei

    2015-09-01

    We have developed an improved and effective method to immobilize Yarrowia lipolytica lipase Lip2 (YLIP2) on an epoxy poly-(glycidylmethacrylate-triallyisocyanurate-ethyleneglycoldimethacrylate) (PGMA-TAIC-EGDMA) support structure with or without amine or/and protein modifications. Our results show that there is an increase in the activity of the immobilized lipase on n-butylamine (BA) modified support (420U/g support) and the biocompatible gelatin modified support (600U/g support) when compared to the support without modification (240U/g support). To further study the influences of BA and gelatin modification on the activity of the immobilized lipase, gelatin and BA were concurrently used to decorate the support structure. Lipase immobilized on 2% BA/gelatin (1:1) modified support obtained the highest activity (1180U/g support), which was five-fold higher than that on a native support structure. These results suggest that the activity of a support-immobilized lipase depends on the support surface properties and a moderate support surface micro-environment was crucial for elevated activity. Collectively, these data show that a combined gelatin and BA modification regulates the support surface more suitable for immobilizing YLIP2. PMID:26073154

  16. Enhanced degradation of 2-nitrotoluene by immobilized cells of Micrococcus sp. strain SMN-1.

    PubMed

    Mulla, Sikandar I; Talwar, Manjunatha P; Bagewadi, Zabin K; Hoskeri, Robertcyril S; Ninnekar, Harichandra Z

    2013-02-01

    Nitrotoluenes are the toxic pollutants of the environment because of their large scale use in the production of explosives. Biodegradation of such chemicals by microorganisms may provide an effective method for their detoxification. We have studied the degradation of 2-nitrotoluene by cells of Micrococcus sp. strain SMN-1 immobilized in various matrices such as polyurethane foam (PUF), sodium alginate (SA), sodium alginate-polyvinyl alcohol (SA-PVA), agar and polyacrylamide. The rate of degradation of 15 and 30 mM 2-nitrotoluene by freely suspended cells and immobilized cells in batches and fed-batch with shaken cultures were compared. The PUF-immobilized cells achieved higher degradation of 15 and 30 mM 2-nitrotoluene than freely suspended cells and the cells immobilized in SA-PVA, polyacrylamide, SA and agar. The PUF-immobilized cells could be reused more than 24 cycles without loosing their degradation capacity and showed more tolerance to pH and temperature changes than freely suspended cells. These results revealed the enhanced rate of degradation of 2-nitrotoluene by PUF-immobilized cells of Micrococcus sp. strain SMN-1. PMID:23153775

  17. Facile, high efficiency immobilization of lipase enzyme on magnetic iron oxide nanoparticles via a biomimetic coating

    PubMed Central

    2011-01-01

    Background Immobilization of lipase on appropriate solid supports is one way to improve their stability and activity, and can be reused for large scale applications. A sample, cost- effective and high loading capacity method is still challenging. Results A facile method of lipase immobilization was developed in this study, by the use of polydopamine coated magnetic nanoparticles (PD-MNPs). Under optimal conditions, 73.9% of the available lipase was immobilized on PD-MNPs, yielding a lipase loading capacity as high as 429 mg/g. Enzyme assays revealed that lipase immobilized on PD-MNPs displayed enhanced pH and thermal stability compared to free lipase. Furthermore, lipase immobilized on PD-MNPs was easily isolated from the reaction medium by magnetic separation and retained more than 70% of initial activity after 21 repeated cycles of enzyme reaction followed by magnetic separation. Conclusions Immobilization of enzyme onto magnetic iron oxide nanoparticles via poly-dopamine film is economical, facile and efficient. PMID:21649934

  18. Improved covalent immobilization of horseradish peroxidase on macroporous glycidyl methacrylate-based copolymers.

    PubMed

    Prodanović, Olivera; Prokopijević, Miloš; Spasojević, Dragica; Stojanović, Zeljko; Radotić, Ksenija; Knežević-Jugović, Zorica D; Prodanović, Radivoje

    2012-11-01

    A macroporous copolymer of glycidyl methacrylate and ethylene glycol dimethacrylate, poly(GMA-co-EGDMA), with various surface characteristics and mean pore size diameters ranging from 44 to 200 nm was synthesized, modified with 1,2-diaminoethane, and tested as a carrier for immobilization of horseradish peroxidase (HRP) by two covalent methods, glutaraldehyde and periodate. The highest specific activity of around 35 U g(-1) dry weight of carrier was achieved on poly(GMA-co-EGDMA) copolymers with mean pore diameters of 200 and 120 nm by the periodate method. A study of deactivation kinetics at 65 °C and in 80 % dioxane revealed that periodate immobilization also produced an appreciable stabilization of the biocatalyst, while stabilization factor depended strongly on the surface characteristics of the copolymers. HRP immobilized on copolymer with a mean pore diameter of 120 nm by periodate method showing not only the highest specific activity but also good stability was further characterized. It appeared that the immobilization resulted in the stabilization of enzyme over a broader pH range while the Michaelis constant value (K (m)) of the immobilized HRP was 10.8 mM, approximately 5.6 times higher than that of the free enzyme. After 6 cycles of repeated use in a batch reactor for pyrogallol oxidation, the immobilized HRP retained 45 % of its original activity. PMID:22941271

  19. Immobilization of Microbes for Bioremediation of Crude Oil Polluted Environments: A Mini Review

    PubMed Central

    Bayat, Zeynab; Hassanshahian, Mehdi; Cappello, Simone

    2015-01-01

    Petroleum hydrocarbons are the most common environmental pollutants in the world and oil spills pose a great hazard to terrestrial and marine ecosystems. Oil pollution may arise either accidentally or operationally whenever oil is produced, transported, stored and processed or used at sea or on land. Oil spills are a major menace to the environment as they severely damage the surrounding ecosystems. To improve the survival and retention of the bioremediation agents in the contaminated sites, bacterial cells must be immobilized. Immobilized cells are widely tested for a variety of applications. There are many types of support and immobilization techniques that can be selected based on the sort of application. In this review article, we have discussed the potential of immobilized microbial cells to degrade petroleum hydrocarbons. In some studies, enhanced degradation with immobilized cells as compared to free living bacterial cells for the treatment of oil contaminated areas have been shown. It was demonstrated that immobilized cell to be effective and is better, faster, and can be occurred for a longer period PMID:26668662

  20. Wheat Bran Enhances the Cytotoxicity of Immobilized Alcaligenes aquatilis F8 against Microcystis aeruginosa

    PubMed Central

    Sun, Pengfei; Lin, Hui; Wang, Guan; Zhang, Ximing; Zhang, Qichun; Zhao, Yuhua

    2015-01-01

    Algicidal bacteria offer a promising option for killing cyanobacteria. Therefore, a new Alcaligenes aquatilis strain F8 was isolated to control Microcystis aeruginosa in this study. The algicidal activity of strain F8 was dependent on the cell density of M. aeruginosa, and the maximal algicidal rate of the free bacterium reached 88.45% within 72 h. With a view to its application to the control of M. aeruginosa in the natural environment, strain F8 was immobilized in sodium alginate beads, but immobilization of the strain decreased its algicidal rate compared to that of the free bacterium. However, addition of wheat bran to the sodium alginate matrix used to immobilize strain F8 not only eliminated the adverse effects of immobilization on the bacteria but also resulted in an 8.83% higher algicidal rate of the immobilized than free bacteria. Exclusion and recovery methods were used to identify key ingredients of wheat bran and gain insight into the mechanism underlying the observed enhancement of algicidal activity. This analysis indicated that certain factors in wheat bran, including vitamins B1, B2, B9, and E were responsible for promoting bacterial growth and thereby improving the algicidal rate of immobilized strain F8. Our findings indicate that wheat bran is able to improve the algicidal efficiency of A. aquatilis strain F8 for killing M. aeruginosa and is a good source of not only carbon and nitrogen but also vitamins for bacteria. PMID:26295573

  1. Immobilization of Bacillus sp. in mesoporous activated carbon for degradation of sulphonated phenolic compound in wastewater.

    PubMed

    Sekaran, G; Karthikeyan, S; Gupta, V K; Boopathy, R; Maharaja, P

    2013-03-01

    Xenobiotic compounds are used in considerable quantities in leather industries besides natural organic and inorganic compounds. These compounds resist biological degradation and thus they remain in the treated wastewater in the unaltered molecular configurations. Immobilization of organisms in carrier matrices protects them from shock load application and from the toxicity of chemicals in bulk liquid phase. Mesoporous activated carbon (MAC) has been considered in the present study as the carrier matrix for the immobilization of Bacillus sp. isolated from Effluent Treatment Plant (ETP) employed for the treatment of wastewater containing sulphonated phenolic (SP) compounds. Temperature, pH, concentration, particle size and mass of MAC were observed to influence the immobilization behavior of Bacillus sp. The percentage immobilization of Bacillus sp. was the maximum at pH 7.0, temperature 20 °C and at particle size 300 μm. Enthalpy, free energy and entropy of immobilization were -46.9 kJ mol(-1), -1.19 kJ mol(-1) and -161.36 JK(-1)mol(-1) respectively at pH 7.0, temperature 20 °C and particle size 300 μm. Higher values of ΔH(0) indicate the firm bonding of the Bacillus sp. in MAC. Degradation of aqueous sulphonated phenolic compound by Bacillus sp. immobilized in MAC followed pseudo first order rate kinetics with rate constant 1.12 × 10(-2) min(-1). PMID:25427481

  2. Influences of apolipoprotein E on soluble and heparin-immobilized hepatic lipase

    SciTech Connect

    Landis, B.A.; Rotolo, F.S.; Meyers, W.C.; Clark, A.B.; Quarfordt, S.H.

    1987-06-01

    The effect of human apolipoprotein E (apoE), either alone or in combination with apoC, on the lipolysis of a radiolabeled triglyceride emulsion was studied with hepatic lipase in solution and immobilized on heparin-Sepharose. The soluble hepatic lipase was inhibited, whereas the heparin-immobilized lipase was stimulated by apoE. This stimulation was attenuated by combining apoE with either apoC-II or C-III. The heparin-immobilized lipase demonstrated much less lipolysis of the zwitterionic phosphatidylcholine-stabilized triglyceride emulsion than did the soluble enzyme. This difference was less when the emulsion was stabilized by a nonionic detergent. apoE inhibited lipase activity when assayed under conditions (0.4 M NaCl) of bound enzyme and unbound substrate. Increasing the emulsion apoE content beyond optimum inhibited lipolysis by the immobilized enzyme. Kinetic analysis of phosphatidylcholine-stabilized triglyceride emulsions revealed a significant decrease in immobilized enzyme K/sub m/ and an increase in V/sub max/ when the emulsion was supplemented with apoE. Distributing the immobilized lipase in clustered aggregates produced more lipolysis than when the same enzyme content was uniformly bound.

  3. Bio-waste derived dialdehyde cellulose ethers as supports for α-chymotrypsin immobilization.

    PubMed

    Kumari, Sapana; Chauhan, Ghanshyam S; Ahn, Jou-Hyeon; Reddy, N S

    2016-04-01

    Enzyme immobilization is an important technique to enhance stability, storability and reusability of enzymes. In the present work, pine needles, a forest bio-waste, were used as a feedstock of cellulose to synthesize new materials as supports for immobilization of α-chymotrypsin (CT) enzyme. The extracted cellulose from pine needles was etherified with different alkyl bromides (RBr) and etherified products were further modified to dialdehyde via oxidation with NaIO4 to get the desired products, dialdehyde cellulose ethers (ROcellCHO). CT was then covalently immobilized onto as-synthesized dialdehyde cellulose ethers via Schiff-base formation, i.e., imine linkage. The synthesized products and enzyme immobilization were confirmed by different characterization techniques and the activity assay of the free and the immobilized CT was carried out using standard protocol with variation of different parameters such as temperature, pH and substrate concentration. The storage stability and reusability of the immobilized CT were also investigated. CT activity was also studied in simulated physiological conditions in the artificial gastric fluid and artificial intestinal fluid. Artificial neural network (ANN) model was employed to correlate the relationship with% relative activity and time, temperature and pH affecting enzyme activity. A good correlation of experimental data was predicted by ANN model. PMID:26723248

  4. Immobilization of Microbes for Bioremediation of Crude Oil Polluted Environments: A Mini Review.

    PubMed

    Bayat, Zeynab; Hassanshahian, Mehdi; Cappello, Simone

    2015-01-01

    Petroleum hydrocarbons are the most common environmental pollutants in the world and oil spills pose a great hazard to terrestrial and marine ecosystems. Oil pollution may arise either accidentally or operationally whenever oil is produced, transported, stored and processed or used at sea or on land. Oil spills are a major menace to the environment as they severely damage the surrounding ecosystems. To improve the survival and retention of the bioremediation agents in the contaminated sites, bacterial cells must be immobilized. Immobilized cells are widely tested for a variety of applications. There are many types of support and immobilization techniques that can be selected based on the sort of application. In this review article, we have discussed the potential of immobilized microbial cells to degrade petroleum hydrocarbons. In some studies, enhanced degradation with immobilized cells as compared to free living bacterial cells for the treatment of oil contaminated areas have been shown. It was demonstrated that immobilized cell to be effective and is better, faster, and can be occurred for a longer period. PMID:26668662

  5. Biosynthesis and Immobilization of Biofunctional Allophycocyanin

    PubMed Central

    Chen, Yingjie; Liu, Shaofang; Cui, Yulin; Jiang, Peng; Chen, Huaxin; Li, Fuchao; Qin, Song

    2011-01-01

    The holo-allophycocyanin-α subunit, which has various reported pharmacological uses, was biosynthesized with both Strep-II-tag and His-tag at the N-terminal in Escherichia coli. The streptavidin-binding ability resulting from the Strep II-tag was confirmed by Western blot. Additionally, the metal-chelating ability deriving from the His-tag not only facilitated its purification by immobilized metal-ion affinity chromatography but also promoted its immobilization on Zn (II)-decorated silica-coated magnetic nanoparticles. The holo-allophycocyanin-α subunit with streptavidin-binding ability was thereby immobilized on magnetic nanoparticles. Magnetic nanoparticles are promising as drug delivery vehicles for targeting and locating at tumors. Thus, based on genetic engineering and nanotechnology, we provide a potential strategy to facilitate the biomodification and targeted delivery of pharmacological proteins. PMID:23008737

  6. [Water binding of adsorptive immobilized lipases].

    PubMed

    Loose, S; Meusel, D; Muschter, A; Ruthe, B

    1990-01-01

    It is supposed that not only the total water content of lipase preparations but more their state of water binding is of technological importance in enzymatic interesterification reactions in systems nearly free from water. The isotherms at 65 degrees C of two microbial lipases immobilized on various adsorbents as well as different adsorbents themselves are shown. The water binding capacity in the range of water content of technological interest decreases from the anion exchange resin Amberlyst A 21 via nonpolar adsorbent Amberlite XAD-2 to kieselguhr Celite 545. It is demonstrated that water binding by lipases is depending on temperature but is also affected by adsorptive immobilization. Adsorptive immobilized lipases show hysteresis, which is very important for preparing a definite water content of the enzyme preparations. PMID:2325750

  7. Plutonium Immobilization Can Loading Conceptual Design

    SciTech Connect

    Kriikku, E.

    1999-05-13

    'The Plutonium Immobilization Facility will encapsulate plutonium in ceramic pucks and seal the pucks inside welded cans. Remote equipment will place these cans in magazines and the magazines in a Defense Waste Processing Facility (DWPF) canister. The DWPF will fill the canister with glass for permanent storage. This report discusses the Plutonium Immobilization can loading conceptual design and includes a process block diagram, process description, preliminary equipment specifications, and several can loading issues. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.'

  8. Applications of immobilized biocatalysts in chemical analysis

    SciTech Connect

    Bowers, L.D.

    1986-04-01

    In 1974, Weetall published a report in Analytical Chemistry documenting the increasing interest in a relatively new concept in catalysis involving enzymes physically or covalently bound to a solid support. Very few reports of a new immobilization chemistry can stir enthusiasm, and the descriptions of new analysis systems have become less and less frequent. With these advances in mind, it seems appropriate to evaluate the use of immobilized enzymes as routine laboratory tools, a prediction made in 1976 (2), and the reasons for the success or failure of the technique. 20 references, 5 figures, 2 tables.

  9. Immobilization of Pb from contaminated water, soils, and wastes by phosphate rock. Annual report, 15 March 1993-14 September 1994

    SciTech Connect

    Ma, Q.Y.; Logan, T.J.; Traina, S.J.

    1994-10-01

    This research studies the feasibility of using phosphate rock and hydroxyapatite to immobilize Pb from aqueous solutions and contaminated soils, investigated the effects of CaCO3, aqueous Ca, Na, and K, and EDTA on aqueous Pb immobilization by hydroxyapatite, examined the stability of hydroxypyromorphite in the presence of high concentrations of anion exhange resin, aqueous Ca(+2), and EDTA, and determined the feasibility of using hydroxyapatite in immobilizing AsO4-3.

  10. Immobilization of Norwegian reindeer (Rangifer tarandus tarandus) and Svalbard Reindeer (R. t. platyrhynchus) with medetomidine and medetomidine-ketamine and reversal of immobilization with atipamezole.

    PubMed

    Tyler, N J; Hotvedt, R; Blix, A S; Sørensen, D R

    1990-01-01

    The sedative action of medetomidine (-ketamine) was studied in 12 captive Norwegian semidomesticated reindeer (NR), including 4 newborn calves, and in 7 free-living Svalbard reindeer (SR). Medetomidine, with or without ketamine, caused effective, reliable immobilization in NR. Doses of 50-200 micrograms/kg medetomidine alone or 30-125 micrograms/kg medetomidine combined with greater than or equal to 300 micrograms/kg ketamine induced complete immobilization, good muscle relaxation and persistent, deep sedation with little respiratory depression in NR; SR required higher doses. Atipamezole successfully antagonized medetomidine (-ketamine) resulting in rapid and persistent reversal of immobilization in all cases (NR and SR). Both medetomidine and atipamezole had wide safety margins and no conspicuous lasting side effects after reversal. PMID:1983084

  11. Metal immobilization in soils using synthetic zeolites.

    PubMed

    Oste, Leonard A; Lexmond, Theo M; Van Riemsdijk, Willem H

    2002-01-01

    In situ immobilization of heavy metals in contaminated soils is a technique to improve soil quality. Synthetic zeolites are potentially useful additives to bind heavy metals. This study selected the most effective zeolite in cadmium and zinc binding out of six synthetic zeolites (mordenite-type, faujasite-type, zeolite X, zeolite P, and two zeolites A) and one natural zeolite (clinoptilolite). Zeolite A appeared to have the highest binding capacity between pH 5 and 6.5 and was stable above pH 5.5. The second objective of this study was to investigate the effects of zeolite addition on the dissolved organic matter (DOM) concentration. Since zeolites increase soil pH and bind Ca, their application might lead to dispersion of organic matter. In a batch experiment, the DOM concentration increased by a factor of 5 when the pH increased from 6 to 8 as a result of zeolite A addition. A strong increase in DOM was also found in the leachate of soil columns, particularly in the beginning of the experiment. This resulted in higher metal leaching caused by metal-DOM complexes. In contrast, the free ionic concentration of Cd and Zn strongly decreased after the addition of zeolites, which might explain the reduction in metal uptake observed in plant growth experiments. Pretreatment of zeolites with acid (to prevent a pH increase) or Ca (to coagulate organic matter) suppressed the dispersion of organic matter, but also decreased the metal binding capacity of the zeolites due to competition of protons or Ca. PMID:12026084

  12. COMPLEXANTS FOR ACTINIDE ELEMENT COORDINATION AND IMMOBILIZATION

    EPA Science Inventory

    We propose that inorganic clusters known as polyoxoanions (POAs) can be exploited as complexants for actinide (An) ion coordination and immobilization. Our objective is to develop rugged, stoichiometrically well-defined POAs that act as molecular containers of An elements. Poly...

  13. Immobilization of plasmid DNA in bacterial ghosts.

    PubMed

    Mayrhofer, Peter; Tabrizi, Chakameh Azimpour; Walcher, Petra; Haidinger, Wolfgang; Jechlinger, Wolfgang; Lubitz, Werner

    2005-02-16

    The development of novel delivery vehicles is crucial for the improvement of DNA vaccine efficiency. In this report, we describe a new platform technology, which is based on the immobilization of plasmid DNA in the cytoplasmic membrane of a bacterial carrier. This technology retains plasmid DNA (Self-Immobilizing Plasmid, pSIP) in the host envelope complex due to a specific protein/DNA interaction during and after protein E-mediated lysis. The resulting bacterial ghosts (empty bacterial envelopes) loaded with pDNA were analyzed in detail by real time PCR assays. We could verify that pSIP plasmids were retained in the pellets of lysed Escherichia coli cultures indicating that they are efficiently anchored in the inner membrane of bacterial ghosts. In contrast, a high percentage of control plasmids that lack essential features of the self-immobilization system were expelled in the culture broth during the lysis process. We believe that the combination of this plasmid immobilization procedure and the protein E-mediated lysis technology represents an efficient in vivo technique for the production of non-living DNA carrier vehicles. In conclusion, we present a "self-loading", non-living bacterial DNA delivery vector for vaccination endowed with intrinsic adjuvant properties of the Gram-negative bacterial cell envelope. PMID:15681093

  14. Plutonium Immobilization Can Loading Preliminary Specifications

    SciTech Connect

    Kriikku, E.

    1998-11-25

    This report discusses the Plutonium Immobilization can loading preliminary equipment specifications and includes a process block diagram, process description, equipment list, preliminary equipment specifications, plan and elevation sketches, and some commercial catalogs. This report identifies loading pucks into cans and backfilling cans with helium as the top priority can loading development areas.

  15. Immobilization: A Revolution in Traditional Brewing

    NASA Astrophysics Data System (ADS)

    Virkajärvi, Ilkka; Linko, Matti

    In nature many micro-organisms tend to bind to solid surfaces. This tendency has long been utilized in a number of processes, for example in producing vinegar and acetic acid in bioreactors filled with wood shavings. Acetobacteria are attached to the surface of these shavings. In modern technical language: they are immobilized. Also yeast cells can be immobilized. In the brewing industry this has been the basis for maintaining efficient, continuous fermentation in bioreactors with very high yeast concentrations. The most dramatic change in brewing over recent years has been the replacement of traditional lagering of several weeks by a continuous process in which the residence time is only about 2h. Continuous primary fermentation is used on a commercial scale in New Zealand. In this process, instead of a carrier, yeast is retained in reactors by returning it partly after separation. In many pilot scale experiments the primary fermentation is shortened from about 1week to 1-2days using immobilized yeast reactors. When using certain genetically modified yeast strains no secondary fermentation is needed, and the total fermentation time in immobilized yeast reactors can therefore be shortened to only 2days.

  16. Immobilization of Enzymes in Polymer Supports.

    ERIC Educational Resources Information Center

    Conlon, Hugh D.; Walt, David R.

    1986-01-01

    Two experiments in which an enzyme is immobilized onto a polymeric support are described. The experiments (which also demonstrate two different polymer preparations) involve: (1) entrapping an enzyme in an acrylamide polymer; and (2) reacting the amino groups on the enzyme's (esterase) lysine residues with an activated polymer. (JN)

  17. Plutonium Immobilization Project -- Robotic canister loading

    SciTech Connect

    Hamilton, L.

    2000-04-28

    The Plutonium Immobilization Program (PIP) is a joint venture between the Savannah River Site, Lawrence Livermore National Laboratory, Argonne National Laboratory, and Pacific Northwest National Laboratory. When operational in 2008, the PIP will fulfill the nation's nonproliferation commitment by placing surplus weapons-grade plutonium in a permanently stable ceramic form.

  18. Immobilization of immunoglobulins on silica surfaces. Stability.

    PubMed Central

    Jönsson, U; Malmqvist, M; Rönnberg, I

    1985-01-01

    The development of new immunosensors based on surface-concentration-measuring devices requires a stable and reproducible immobilization of antibodies on well-characterized solid surfaces. We here report on the immobilization of immunoglobulin G (IgG) on chemically modified silica surfaces. Such surfaces may be used in various surface-oriented analytical methods. Reactive groups were introduced to the silica surfaces by chemical-vapour deposition of silane. The surfaces were characterized by ellipsometry, contact-angle measurements and scanning electron microscopy. IgG covalently bound by the use of thiol-disulphide exchange reactions, thereby controlling the maximum number of covalent bonds to the surface, was compared with IgG adsorbed on various silica surfaces. This comparison showed that the covalently bound IgG has a superior stability when the pH was lowered or incubation with detergents, urea or ethylene glycol was carried out. The result was evaluated by ellipsometry, an optical technique that renders possible the quantification of amounts of immobilized IgG. The results outline the possibilities of obtaining a controlled covalent binding of biomolecules to solid surfaces with an optimal stability and biological activity of the immobilized molecules. Images Fig. 3. PMID:2988497

  19. Short-Term Limb Immobilization Affects Cognitive Motor Processes

    ERIC Educational Resources Information Center

    Toussaint, Lucette; Meugnot, Aurore

    2013-01-01

    We examined the effects of a brief period of limb immobilization on the cognitive level of action control. A splint placed on the participants' left hand was used as a means of immobilization. We used a hand mental rotation task to investigate the immobilization-induced effects on motor imagery performance (Experiments 1 and 2) and a number mental…

  20. Immobilization of α-Amylase from Anoxybacillus sp. SK3-4 on ReliZyme and Immobead Supports.

    PubMed

    Kahar, Ummirul Mukminin; Sani, Mohd Helmi; Chan, Kok-Gan; Goh, Kian Mau

    2016-01-01

    α-Amylase from Anoxybacillus sp. SK3-4 (ASKA) is a thermostable enzyme that produces a high level of maltose from starches. A truncated ASKA (TASKA) variant with improved expression and purification efficiency was characterized in an earlier study. In this work, TASKA was purified and immobilized through covalent attachment on three epoxide (ReliZyme EP403/M, Immobead IB-150P, and Immobead IB-150A) and an amino-epoxide (ReliZyme HFA403/M) activated supports. Several parameters affecting immobilization were analyzed, including the pH, temperature, and quantity (mg) of enzyme added per gram of support. The influence of the carrier surface properties, pore sizes, and lengths of spacer arms (functional groups) on biocatalyst performances were studied. Free and immobilized TASKAs were stable at pH 6.0-9.0 and active at pH 8.0. The enzyme showed optimal activity and considerable stability at 60 °C. Immobilized TASKA retained 50% of its initial activity after 5-12 cycles of reuse. Upon degradation of starches and amylose, only immobilized TASKA on ReliZyme HFA403/M has comparable hydrolytic ability with the free enzyme. To the best of our knowledge, this is the first report of an immobilization study of an α-amylase from Anoxybacillus spp. and the first report of α-amylase immobilization using ReliZyme and Immobeads as supports. PMID:27618002

  1. Immobilized acclimated biomass-powdered activated carbon for the bioregeneration of granular activated carbon loaded with phenol and o-cresol.

    PubMed

    Toh, Run-Hong; Lim, Poh-Eng; Seng, Chye-Eng; Adnan, Rohana

    2013-09-01

    The objectives of the study are to use immobilized acclimated biomass and immobilized biomass-powdered activated carbon (PAC) as a novel approach in the bioregeneration of granular activated carbon (GAC) loaded with phenol and o-cresol, respectively, and to compare the efficiency and rate of the bioregeneration of the phenolic compound-loaded GAC using immobilized and suspended biomasses under varying GAC dosages. Bioregeneration of GAC loaded with phenol and o-cresol, respectively, was conducted in batch system using the sequential adsorption and biodegradation approach. The results showed that the bioregeneration efficiency of GAC loaded with phenol or o-cresol was basically the same irrespective of whether the immobilized or suspended biomass was used. Nonetheless, the duration for bioregeneration was longer under immobilized biomass. The beneficial effect of immobilized PAC-biomass for bioregeneration is the enhancement of the removal rate of the phenolic compounds via adsorption and the shortening of the bioregeneration duration. PMID:23796608

  2. Site directed immobilization of glucose-6-phosphate dehydrogenase via thiol-disulfide interchange: influence on catalytic activity of cysteines introduced at different positions.

    PubMed

    Simons, J R; Mosisch, M; Torda, A E; Hilterhaus, L

    2013-08-10

    This study shows the effect of site-directed enzyme immobilization upon the enzyme activity of covalently bound glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides. Immobilization points were introduced at sterically accessible sites in order to control the protein's orientation and twice as much activity was recovered in comparison to conventionally immobilized enzyme. Immobilization of G6PDH via genetically engineered cysteine provided a simple, but effective method to control the immobilization process. G6PDH variants with cysteine close to the active center (L218C), close to the dimer interface (D205C) as well as far from the active center (D453C) showed changes in activity and the efficacy of immobilization. PMID:23770076

  3. Phase 1 immobilized low-activity waste operational source term

    SciTech Connect

    Burbank, D.A.

    1998-03-06

    This report presents an engineering analysis of the Phase 1 privatization feeds to establish an operational source term for storage and disposal of immobilized low-activity waste packages at the Hanford Site. The source term information is needed to establish a preliminary estimate of the numbers of remote-handled and contact-handled waste packages. A discussion of the uncertainties and their impact on the source term and waste package distribution is also presented. It should be noted that this study is concerned with operational impacts only. Source terms used for accident scenarios would differ due to alpha and beta radiation which were not significant in this study.

  4. Optimizing immobilized enzyme performance in cell-free environments to produce liquid fuels.

    SciTech Connect

    Kumar, Sanat

    2015-02-05

    The overall goal of this project was to optimize enzyme performance for the production of bio-diesel fuel. Enzyme immobilization has attracted much attention as a means to increase productivity. Mesorporous silica materials have been known to be best suited for immobilizing enzymes. A major challenge is to ensure that the enzymatic activity is retained after immobilization. Two major factors which drive enzymatic deactivation are protein-surface and inter-protein interactions. Previously, we studied protein stability inside pores and how to optimize protein-surface interactions to minimize protein denaturation. In this work we studied eh effect of surface curvature and chemistry on inter-protein interactions. Our goal was to find suitable immobilization supports which minimize these inter-protein interactions. Our studies carried out in the frame work of Hydrophobic-Polar (HP) model showed that enzymes immobilized inside hydrophobic pores of optimal sizes are best suited to minimize these inter-protein interactions. Besides, this study is also of biological importance to understand the role of chaperonins in protein disaggregation. Both of these aspects profited immensely with collaborations with our experimental colleague, Prof. Georges Belfort (RPI), who performed the experimental analog of our theoretical works.

  5. Characteristic features and dye degrading capability of agar-agar gel immobilized manganese peroxidase.

    PubMed

    Bilal, Muhammad; Asgher, Muhammad; Shahid, Muhammad; Bhatti, Haq Nawaz

    2016-05-01

    Immobilization of enzymes has been regarded as an efficient approach to develop biocatalyst with improved activity and stability characteristics under reaction conditions. In the present study, purified manganese peroxidase (MnP) from Ganoderma lucidum IBL-05 was immobilized in agar-agar support using entrapment technique. Maximum immobilization yield was accomplished at 4.0% agar-agar gel. The immobilized MnP exhibited better resistance to changes in pH and temperature than the free enzyme, with optimal conditions being pH 6.0 and 50 °C. The kinetic parameters Km and Kcat/Km for free and entrapped MnP were calculated to be 65.6 mM and 6.99 M(-1) s(-1), and 82 mM and 8.15 M(-1) s(-1), respectively. Thermo-stability was significantly improved after immobilization. After 120 h, the insolubilized MnP retained its activity up to 71.9% and 60.3% at 30 °C and 40 °C, respectively. It showed activity until 10th cycle and retained 74.3% residual activity after 3th cycle. The effects of H2O2, ionic strength and potential inhibitors on activity of free and immobilized enzyme were investigated. Moreover, the decolorization of three structurally different dyes was monitored in order to assess the degrading capability of the entrapped MnP. The decolorization efficiencies for all the tested dyes were 78.6-84.7% after 12h. The studies concluded that the toxicity of dyes aqueous solutions was significantly reduced after treatment. The remarkable catalytic, thermo-stability and re-cycling features of the agar-agar immobilized MnP display a high potential for biotechnological applications. PMID:26854887

  6. Covalent immobilization of glucose oxidase onto new modified acrylonitrile copolymer/silica gel hybrid supports.

    PubMed

    Godjevargova, Tzonka; Nenkova, Ruska; Dimova, Nedyalka

    2005-08-12

    New polymer/silica gel hybrid supports were prepared by coating high surface area of silica gel with modified acrylonitrile copolymer. The concentrations of the modifying agent (NaOH) and the modified polymer were varied. GOD was covalently immobilized on these hybrid supports and the relative activity and the amount of bound protein were determined. The highest relative activity and sufficient amount of bound protein of the immobilized GOD were achieved in 10% NaOH and 2% solution of modified acrylonitrile copolymer. The influence of glutaraldehyde concentration and the storage time on enzyme efficiency were examined. Glutaraldehyde concentration of 0.5% is optimal for the immobilized GOD. It was shown that the covalently bound enzyme (using 0.5% glutaraldehyde) had higher relative activity than the activity of the adsorbed enzyme. Covalently immobilized GOD with 0.5% glutaraldehyde was more stable for four months in comparison with the one immobilized on pure silica gel, hybrid support with 10% glutaraldehyde and the free enzyme. The effect of the pore size on the enzyme efficiency was studied on four types of silica gel with different pore size. Silica with large pores (CPC-Silica carrier, 375 A) presented higher relative activity than those with smaller pore size (Silica gel with 4, 40 and 100 A). The amount of bound protein was also reduced with decreasing the pore size. The effect of particle size was studied and it was found out that the smaller the particle size was, the greater the activity and the amount of immobilized enzyme were. The obtained results proved that these new polymer/silica gel hybrid supports were suitable for GOD immobilization. PMID:16080168

  7. Immobilization of antibacterial chlorhexidine on stainless steel using crosslinking polydopamine film: Towards infection resistant medical devices.

    PubMed

    Mohd Daud, Nurizzati; Saeful Bahri, Ihda Fithriyana; Nik Malek, Nik Ahmad Nizam; Hermawan, Hendra; Saidin, Syafiqah

    2016-09-01

    Chlorhexidine (CHX) is known for its high antibacterial substantivity and is suitable for use to bio-inert medical devices due to its long-term antibacterial efficacy. However, CHX molecules require a crosslinking film to be stably immobilized on bio-inert metal surfaces. Therefore, polydopamine (PDA) was utilized in this study to immobilize CHX on the surface of 316L type stainless steel (SS316L). The SS316L disks were pre-treated, modified with PDA film and immobilized with different concentrations of CHX (10mM-50mM). The disks were then subjected to various surface characterization analyses (ATR-FTIR, XPS, ToF-SIMS, SEM and contact angle measurement) and tested for their cytocompatibility with human skin fibroblast (HSF) cells and antibacterial activity against Escherichia coli and Staphylococcus aureus. The results demonstrated the formation of a thin PDA film on the SS316L surface, which acted as a crosslinking medium between the metal and CHX. CHX was immobilized via a reduction process that covalently linked the CHX molecules with the functional group of PDA. The immobilization of CHX increased the hydrophobicity of the disk surfaces. Despite this property, a low concentration of CHX optimized the viability of HSF cells without disrupting the morphology of adherent cells. The immobilized disks also demonstrated high antibacterial efficacy against both bacteria, even at a low concentration of CHX. This study demonstrates a strong beneficial effect of the crosslinked PDA film in immobilizing CHX on bio-inert metal, and these materials are applicable in medical devices. Specifically, the coating will restrain bacterial proliferation without suffocating nearby tissues. PMID:27153117

  8. Fiber Optic Chemical Sensors Using Immobilized Bioreceptors

    NASA Astrophysics Data System (ADS)

    Walt, David R.; Luo, Shufang; Munkholm, Christiane

    1988-06-01

    Optrodes employing immobilized enzymes were developed using covalent attachment of sensor reagents. This development is an extension of the original application of this sensor technology in which a pH sensor was constructed with the pH sensitive dye fluorescein incorporated into a polymer covalently attached to the fiber tip. This sensor displayed significantly improved response times over previous fiber optic sensors because of reduced diffusion limitations. In addition, the signal intensities were greatly enhanced by the high concentration of fluorescent dye localized at the fiber tip. With the anticipation that these qualities would be preserved, a class of sensors based on the immobilization of biomolecules in the polymer matrix became the next goal. This paper will first describe a fiber optic probe prepared by immobilizing esterase in a crosslinked polyacrylamide matrix. The immobilized esterase converts the nonfluorescent fluoresceindiacetate into fluorescein. Both the steady state level and kinetic generation of fluorescence can be related to the concentration of fluoresceindiacetate. A fiber optic sensor for penicillin has been made by coimmobili zing penicillinase with a pH sensitive fluorescent dye. Penicillinase converts penicillin to penicilloic acid which produces a microenvironmental pH change in the dye-containing polymer matrix resulting in a concommitant change in fluorescence. The change in fluorescence is proportional to the concentration of penicillin and a 95% response is reached in 40-60 seconds. The sensor has a detection limit of 2.5 x 10-4 M. Another class of sensors using immobilized bioreceptors will be based on the principles of fluoroimmunoassay. This paper will discuss some basic principles and problems of 1) fluorescence quenching immunoassays, 2) fluorescence excitation transfer immunoassays, and 3) energy transfer immunoassays for digoxin. Both advantages and inherent problems for these sensor preparations will be addressed.

  9. Immobilization of Active Bacteriophages on Polyhydroxyalkanoate Surfaces.

    PubMed

    Wang, Chanchan; Sauvageau, Dominic; Elias, Anastasia

    2016-01-20

    A rapid, efficient technique for the attachment of bacteriophages (phages) onto polyhydroxyalkanoate (PHA) surfaces has been developed and compared to three reported methods for phage immobilization. Polymer surfaces were modified to facilitate phage attachment using (1) plasma treatment alone, (2) plasma treatment followed by activation by 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride (EDC) and N-hydroxysulfosuccinimide (sulfo-NHS), (3) plasma-initiated acrylic acid grafting, or (4) plasma-initiated acrylic acid grafting with activation by EDC and sulfo-NHS. The impact of each method on the surface chemistry of PHA was investigated using contact angle analysis and X-ray photoelectron spectroscopy. Each of the four treatments was shown to result in both increased hydrophilicity and in the modification of the surface functional groups. Modified surfaces were immersed in suspensions of phage T4 for immobilization. The highest level of phage binding was observed for the surfaces modified by plasma treatment alone. The change in chemical bond states observed for surfaces that underwent plasma treatment is suspected to be the cause of the increased binding of active phages. Plasma-treated surfaces were further analyzed through phage-staining and fluorescence microscopy to assess the surface density of immobilized phages and their capacity to capture hosts. The infective capability of attached phages was confirmed by exposing the phage-immobilized surfaces to the host bacteria Escherichia coli in both plaque and infection dynamic assays. Plasma-treated surfaces with immobilized phages displayed higher infectivity than surfaces treated with other methods; in fact, the equivalent initial multiplicity of infection was 2 orders of magnitude greater than with other methods. Control samples - prepared by immersing polymer surfaces in phage suspensions (without prior plasma treatment) - did not show any bacterial growth inhibition, suggesting they did not bind

  10. Microbial Uranium Immobilization Independent of Nitrate Reduction

    SciTech Connect

    Madden, Andrew; Smith, April; Balkwill, Dr. David; Fagan, Lisa Anne; Phelps, Tommy Joe

    2007-01-01

    At many uranium processing and handling facilities, including sites in the U.S. Department of Energy (DOE) complex, high levels of nitrate are present as co-contamination with uranium in groundwater. The daunting prospect of complete nitrate removal prior to the reduction of uranium provides a strong incentive to explore bioremediation strategies that allow for uranium bioreduction and stabilization in the presence of nitrate. Typical in-situ strategies involving the stimulation of metal-reducing bacteria are hindered by low pH environments at this study site and require that the persistent nitrate must first and continuously be removed or transformed prior to uranium being a preferred electron acceptor. This project investigates the possibility of stimulating nitrate-indifferent, pH-tolerant microorganisms to achieve bioreduction of U(VI) despite nitrate persistence. Successful enrichments from U-contaminated sediments demonstrated nearly complete reduction of uranium with very little loss of nitrate from pH 4.9-5.6 using methanol or glycerol as a carbon source. Higher pH enrichments also demonstrated similar U reduction capacity with 5-30% nitrate loss within one week. Bacterial 16S rRNA genes were amplified from uranium-reducing enrichments (pH 5.7-6.7) and sequenced. Phylogenetic analyses classified the clone sequences into four distinct clusters. Data from sequencing and T-RFLP profiles indicated that the majority of the microorganisms stimulated by these enrichment conditions consisted of low G+C Gram-positive bacteria most closely related to Clostridium and Clostridium-like organisms. This research demonstrates that the stimulation of a natural microbial community to immobilize U through bioreduction is possible without the removal of nitrate.

  11. Effects of RGD immobilization on light-induced cell sheet detachment from TiO2 nanodots films.

    PubMed

    Cheng, Kui; Wang, Tiantian; Yu, Mengliu; Wan, Hongping; Lin, Jun; Weng, Wenjian; Wang, Huiming

    2016-06-01

    Light-induced cell detachment is reported to be a safe and effective cell sheet harvest method. In the present study, the effects of arginine-glycine-aspartic acid (RGD) immobilization on cell growth, cell sheet construction and cell harvest through light illumination are investigated. RGD was first immobilized on TiO2 nanodots films through simple physical adsorption, and then mouse pre-osteoblastic MC3T3-E1 cells were seeded on the films. It was found that RGD immobilization promoted cell adhesion and proliferation. It was also observed that cells cultured on RGD immobilized films showed relatively high level of pan-cadherin. Cells harvested with ultraviolet illumination (365nm) showed good viability on both RGD immobilized and unmodified TiO2 nanodot films. Single cell detachment assay showed that cells detached more quickly on RGD immobilized TiO2 nanodot films. That could be ascribed to the RGD release after UV365 illumination. The current study demonstrated that RGD immobilization could effectively improve both the cellular responses and light-induced cell harvest. PMID:27040216

  12. Degradation of mix hydrocarbons by immobilized cells of mix culture using a trickle fluidized bed reactor. Annual progress report, June 1992--May 1993

    SciTech Connect

    Chapatwala, K.D.

    1993-06-01

    The microorganisms, capable of degrading mix hydrocarbons were isolated from the soil samples collected from the hydrocarbon contaminated sites. The mix cultures were immobilized in calcium alginate solution in the form of beads. A trickle fluidized bed air-uplift-type reactor designed to study the degradation of mix hydrocarbons was filled with 0.85% normal saline containing the immobilized cells of mix culture. The immobilized beads were aerated with CO{sub 2}-free air at 200 ml/min. The degradation of different concentrations of hydrocarbons in the presence/absence of commercially available fertilizers by the immobilized cells of mix culture is now in progress.

  13. Immobilization and light-dark cycle-induced modulation of serotonin metabolism in rat brain and of lymphocyte subpopulations: in vivo voltammetric and FACS analyses.

    PubMed

    Wesemann, W; Clement, H W; Gemsa, D; Hasse, C; Heymanns, J; Pohlner, K; Schäfer, F; Weiner, N

    1993-01-01

    The effect of immobilization and light-dark cycle on the serotoninergic system of the n. raphe dorsalis and on the distribution of blood lymphocyte subpopulations was studied in the rat. As was shown by in vivo voltammetry, 10 min immobilization enhanced serotonin metabolism with a maximum 15 min after immobilization. The distribution of the blood lymphocytes into subpopulations was also affected: pan-T and T helper lymphocytes were reduced during immobilization and reached minimum values after 20 min recovery. The circadian rhythms of serotonin metabolism and the distribution of pan-T and T helper cells exhibited a slight phase shift if compared with each other. PMID:7504793

  14. Influence of immobilized biomolecules on magnetic bead plug formation and retention in capillary electrophoresis.

    PubMed

    Henken, Rachel L; Chantiwas, Rattikan; Gilman, S Douglass

    2012-03-01

    Significant changes in the formation and retention of magnetic bead plugs in a capillary during electrophoresis were studied, and it was demonstrated that these effects were due to the type of biological molecule immobilized on the surface of these beads. Three biological molecules, an antibody, an oligonucleotide, and alkaline phosphatase (AP), were attached to otherwise identical streptavidin-coated magnetic beads through biotin-avidin binding in order to isolate differences in bead immobilization in a magnetic field resulting from the type of biological molecule immobilized on the bead surface. AP was also attached to the magnetic beads using epoxy groups on the bead surfaces (instead of avidin-biotin binding) to study the impact of immobilization chemistry. The formation and retention of magnetic bead plugs were studied quantitatively using light scattering detection of magnetic particles eluting from the bead plugs and qualitatively using microscopy. Both the types of biomolecule immobilized on the magnetic bead surface and the chemistry used to link the biomolecule to the magnetic bead impacted the formation and retention of the bead plugs. PMID:22437880

  15. in situ Calcite Precipitation for Contaminant Immobilization

    SciTech Connect

    Yoshiko Fujita; Robert W. Smith

    2009-08-01

    in situ Calcite Precipitation for Contaminant Immobilization Yoshiko Fujita (Yoshiko.fujita@inl.gov) (Idaho National Laboratory, Idaho Falls, Idaho, USA) Robert W. Smith (University of Idaho-Idaho Falls, Idaho Falls, Idaho, USA) Subsurface radionuclide and trace metal contaminants throughout the U.S. Department of Energy (DOE) complex pose one of DOE’s greatest challenges for long-term stewardship. One promising stabilization mechanism for divalent trace ions, such as the short-lived radionuclide strontium-90, is co-precipitation in calcite. Calcite, a common mineral in the arid western U.S., can form solid solutions with trace metals. The rate of trace metal incorporation is susceptible to manipulation using either abiotic or biotic means. We have previously demonstrated that increasing the calcite precipitation rate by stimulating the activity of urea hydrolyzing microorganisms can result in significantly enhanced Sr uptake. Urea hydrolysis causes the acceleration of calcium carbonate precipitation (and trace metal co-precipitation) by increasing pH and alkalinity, and also by liberating the reactive cations from the aquifer matrix via exchange reactions involving the ammonium ion derived from urea: H2NCONH2 + 3H2O ? 2NH4+ + HCO3- + OH- urea hydrolysis >X:2Ca + 2NH4+ ? 2>X:NH4 + Ca2+ ion exchange Ca2+ + HCO3- + OH- ? CaCO3(s) + H2O calcite precipitation where >X: is a cation exchange site on the aquifer matrix. This contaminant immobilization approach has several attractive features. Urea hydrolysis is catalyzed by the urease enzyme, which is produced by many indigenous subsurface microorganisms. Addition of foreign microbes is unnecessary. In turn the involvement of the native microbes and the consequent in situ generation of reactive components in the aqueous phase (e.g., carbonate and Ca or Sr) can allow dissemination of the reaction over a larger volume and/or farther away from an amendment injection point, as compared to direct addition of the reactants at

  16. Impact of immobilized polysaccharide chiral stationary phases on enantiomeric separations.

    PubMed

    Ali, Imran; Aboul-Enein, Hassan Y

    2006-04-01

    Immobilized polysaccharide-based chiral stationary phases (CSPs) are gaining importance in the resolution of racemic compounds due to their stable nature on working with normal solvents and those prohibited for use with coated phases (tetrahydrofuran, chloroform, dichloromethane, acetone, 1,4-dioxane, ethyl acetate, and certain other ethers). This review discusses the use of immobilized polysaccharide CSPs in the chiral resolution of various racemates by liquid chromatography. The discussion includes immobilization methodologies, enantioselectivities, efficiencies, and a comparison of chiral recognition capabilities of coated vs. immobilized CSPs. Some applications of immobilized CSPs to the chiral resolution of racemic compounds are also presented. PMID:16830488

  17. Mussel-inspired immobilization of vascular endothelial growth factor (VEGF) for enhanced endothelialization of vascular grafts.

    PubMed

    Shin, Young Min; Lee, Yu Bin; Kim, Seok Joo; Kang, Jae Kyeong; Park, Jong-Chul; Jang, Wonhee; Shin, Heungsoo

    2012-07-01

    Most polymeric vascular prosthetic materials have low patency rate for replacement of small diameter vessels (<5 mm), mainly due to failure to generate healthy endothelium. In this study, we present polydopamine-mediated immobilization of growth factors on the surface of polymeric materials as a versatile tool to modify surface characteristics of vascular grafts potentially for accelerated endothelialization. Polydopamine was deposited on the surface of biocompatible poly(L-lactide-co-ε-caprolactone) (PLCL) elastomer, on which vascular endothelial growth factor (VEGF) was subsequently immobilized by simple dipping. Surface characteristics and composition were investigated by using scanning electron microscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. Immobilization of VEGF on the polydopamine-deposited PLCL films was effective (19.8 ± 0.4 and 197.4 ± 19.7 ng/cm(2) for DPv20 and DPv200 films, respectively), and biotin-mediated labeling of immobilized VEGF revealed that the fluorescence intensity increased as a function of the concentration of VEGF solution. The effect of VEGF on adhesion of HUVECs was marginal, which may have been masked by polydopamine layer that also enhanced cell adhesion. However, VEGF-immobilized substrate significantly enhanced proliferation of HUVECs for over 7 days of in vitro culture and also improved their migration. In addition, immobilized VEGF supported robust cell to cell interactions with strong expression of CD 31 marker. The same process was effective for immobilization of basic fibroblast growth factor, demonstrating the robustness of polydopamine layer for secondary ligation of growth factors as a simple and novel surface modification strategy for vascular graft materials. PMID:22617001

  18. The impact of immobile zones on the transport and retention of nanoparticles in porous media

    NASA Astrophysics Data System (ADS)

    Molnar, Ian L.; Gerhard, Jason I.; Willson, Clinton S.; O'Carroll, Denis M.

    2015-11-01

    Nanoparticle transport and retention within porous media is treated by conceptualizing the porous media as a series of independent collectors (e.g., Colloid Filtration Theory). This conceptualization assumes that flow phenomena near grain-grain contacts, such as immobile zones (areas of low flow), exert a negligible influence on nanoparticle transport and assumes that retention and release of particles depends only on surface chemistry. This study investigated the impact of immobile zones on nanoparticle transport and retention by employing synchrotron X-ray computed microtomography (SXCMT) to examine pore-scale silver nanoparticle distributions during transport through three sand columns: uniform iron oxide, uniform quartz, and well-graded quartz. Extended tailing was observed during the elution phase of all experiments suggesting that hydraulic retention in immobile zones, not detachment from grains, was the source of tailing. A numerical simulation of fluid flow through an SXCMT data set predicted the presence of immobile zones near grain-grain contacts. SXCMT-determined silver nanoparticle concentrations observed that significantly lower nanoparticle concentrations existed near grain-grain contacts throughout the duration of all experiments. In addition, the SXCMT-determined pore-scale concentration gradients were found to be independent of surface chemistry and grain size distribution, suggesting that immobile zones limit the diffusive transport of nanoparticles toward the collectors. These results suggest that the well-known overprediction of nanoparticle retention by traditional CFT may be due to ignoring the influences of grain-grain contacts and immobile zones. As such, accurate prediction of nanoparticle transport requires consideration of immobile zones and their influence on both hydraulic and surface retention.

  19. Strength of interactions between immobilized dye molecules and sol-gel matrices.

    PubMed

    Ismail, Fanya; Schoenleber, Monika; Mansour, Rolan; Bastani, Behnam; Fielden, Peter; Goddard, Nicholas J

    2011-02-21

    In this paper we present a new theory to re-examine the immobilization technique of dye doped sol-gel films, define the strength and types of possible bonds between the immobilized molecule and sol-gel glass, and show that the immobilized molecule is not free inside the pores as was previously thought. Immobilizing three different pH sensitive dyes with different size and functional groups inside the same sol-gel films revealed important information about the nature of the interaction between the doped molecule and the sol-gel matrix. The samples were characterized by means of ultraviolet-visible spectrophotometer (UV-VIS), thermal gravimetric analysis (TGA), mercury porosimetry (MP), nuclear magnetic resonance spectroscopy ((29)Si NMR) and field-emission environmental scanning electron microscopy (ESEM-FEG). It was found that the doped molecule itself has a great effect on the strength and types of the bonds. A number of factors were identified, such as number and types of the functional groups, overall charge, size, pK(a) and number of the silanol groups which surround the immobilized molecule. These results were confirmed by the successful immobilization of bromocresol green (BCG) after a completely polymerized sol-gel was made. The sol-gel consisted of 50% tetraethoxysilane (TEOS) and 50% methyltriethoxysilane (MTEOS) (w/w). Moreover, the effect of the immobilized molecule on the structure of the sol-gel was studied by means of a leaky waveguide (LW) mode for doped films made before and after polymerization of the sol-gel. PMID:21120245

  20. Does dynamic immobilization reduce chondrocyte apoptosis and disturbance to the femoral head perfusion?

    PubMed Central

    Li, Lian-Yong; Zhang, Li-Jun; Jia, Jing-Yu; Zhao, Qun; Wang, En-bo; Li, Qi-Wei

    2013-01-01

    The purpose of this study is to investigate whether the dynamic hip immobilization is more favourable for lessening ischemic injury to the immature femoral head than a static immobilization. 152 Japanese white rabbits were divided into four groups randomly, and the hips were immobilized into “human” position (group A), “frog leg” position (group B) and “dynamic frog leg” position (group C). Group D was used as control. Ten rabbits in each group were killed, and the hip specimens were harvested at 1, 2, and 3 weeks after immobilization. Bcl-2/Bax expression balance and chondrocytes apoptosis were analyzed. The remaining eight rabbits in each group were used to measure the blood supply of capital femoral epiphysis by selective vascular perfusion with Indian ink. The Bcl-2/Bax expression ratio in group C was significantly increased than that in group A and B (p<0.001), while that was not significantly different from control group (p=0.0592). At three weeks after immobilization, the average apoptotic ratio was 36.7%, 45.8%, and 26.7% in group A, B and C, respectively (p<0.01). There was no significant difference between group C and normal control (p=0.0597). The perfusion ratio was 0.03±0.03, 0.03±0.02, and 0.08±0.03 in group A, B and C respectively, and 0.12±0.04 in control group (p<0.05). Thus, the dynamic immobilization model exhibited a relatively less chondrocytes apoptosis and disturbance to the femoral head perfusion than other immobilizations in vivo, which therefore may be useful for reducing avascular necrosis following the treatment of developmental dysplasia of the hip. PMID:23330006

  1. Immobilized bacterial spores for use as bioindicators in the validation of thermal sterilization processes.

    PubMed

    Serp, D; von Stockar, U; Marison, I W

    2002-07-01

    Spores of Bacillus subtilis ATCC 6051 and Bacillus stearothermophilus NCTC 10003 were immobilized in monodisperse alginate beads (diameter, 550 microm +/- 5%), and the capacity of the immobilized bioindicators to provide accurate and reliable F-values for sterilization processes was studied. The resistance of the beads to abrasion and heat was strong enough to ensure total retention of the bioindicators in the beads in a sterilization cycle. D- and z-values for free spores were identical to those for immobilized spores, which shows that immobilization does not modify the thermal resistance of the bioindicators. A D(100 degrees C) value of 1.5 min was found for free and immobilized B. subtilis spores heated in demineralized water, skimmed milk, and milk containing 4% fat, suggesting that a lipid concentration as low as 4% does not alter the thermal resistance of B. subtilis spores. Providing that the pH range is kept between 3.4 to 10 and that sufficiently low concentrations of Ca2+ competitors or complexants are present in the medium, immobilized bioindicators may serve as an efficient, accurate, and reliable tool with which to validate the efficiency of any sterilization process. The environmental factors (pH, media composition) affecting the thermoresistance of native contaminants are intrinsically reflected in the F-value, allowing for a sharper adjustment of the sterilization process. Immobilized spores of B. stearothermophilus were successfully used to validate a resonance and interference microwave system that is believed to offer a convenient alternative for the sterilization of temperature-sensitive products and medical wastes. PMID:12117247

  2. Engineering cholesterol-based fibers for antibody immobilization and cell capture

    NASA Astrophysics Data System (ADS)

    Cohn, Celine

    abilities of the CSS fibers were compared to that of hydrophobic polycaprolactone (PCL) fibers and hydrophilic plasma-treated PCL fibers. Electrospun CSS fibers were found to immobilize equivalent amounts of protein as hydrophobically immobilized proteins. However, these proteins captured 6 times more cells, indicative of retained protein function. The second key concept was the design and fabrication of a hybridized lipid fiber. Lipid fibers provide improved protein function but fabrication difficulties have limited their adoption. Thus, we sought to fabricate a lipid-polymer hybrid that is easily fabricated while maintaining protein function. The hybrid fiber consists of a PCL backbone with conjugated CSS. The hybrid lipid fibers showed improved protein function. In addition, higher lipid concentrations were directly correlated to higher cell capture efficiencies. The third key concept was on the development of dually functionalized lipid fibers and understanding the resulting cell capture efficiencies. Many platforms are unable to simultaneously search for heterogeneous populations of CTCs -- the ability to dually functionalize cell-capturing platforms would address this technological weakness. Studies indicated that dually functionalizing the lipid fibers did not compromise the platforms' abilities to capture the cells of interest. Such dually functionalized fibers allow for a single cell-capture platform to successfully detect heterogeneous populations of CTCs. The body of work encompassed herein describes the use of lipid fibers for antibody immobilization and cell capture. Data from various projects indicate that the use of cholesterol-based fibers produced from electrospun CSS are well suited for protein immobilization. The CSS fibers are able to immobilize equivalent amounts of protein as compared to other immobilization techniques. However, the benefit of these fibers is illustrated by the strong cell-capturing efficiencies, indicating that the immobilized

  3. Plutonium Immobilization Project comparison of bagless transfer and electrolytic decon

    SciTech Connect

    Ward, C.R.

    2000-02-15

    This report documents a study requested for PIP to compare the baseline bagless transfer process with the electrolytic decontamination process, and recommend the process for the PIP application. Two different methods of packaging pucks in cans for the Plutonium Immobilization Project (PIP) were compared; the SRS bagless transfer and electrolytic decontamination. The SRS bagless transfer generates more waste, but it is simpler, less systems would be required, it requires much less glovebox space, much less building space and the installed cost would be considerably less. Therefore, the SRS bagless transfer is recommended for the PIP.

  4. Immobilization of amyloglucosidase using two forms of polyurethane polymer.

    PubMed

    Storey, K B; Duncan, J A; Chakrabarti, A C

    1990-03-01

    Amyloglucosidase was covalently immobilized using two hydrophilic prepolymers: Hypol FHP 2002 (creates foams) and Hypol FHP 8190H (creates gels). The foamable prepolymer was superior as a support for enzyme immobilization. The percent activity immobilized in the polyurethane foams was 25 +/- 1.5%. Large substrates (greater than 200,000 daltons in mol wt) were hydrolyzed as effectively as smaller ones by the immobilized enzyme. The Km value of the foam-immobilized enzyme increased from 0.76 mg/mL (free) to 0.86 mg/mL (immobilized), whereas the Vmax dropped from 90.9 (free) to 12.4 nmol glucose/min/mL (immobilized). The long-term (2 mo) storage stability of amyloglucosidase was enhanced by immobilization in foams (70% activity retained; free enzyme only retained 50%). Immobilization also improved the enzyme stability to various denaturing agents (sodium chloride, urea, and ethanol). The immobilized enzyme exhibited increased stability compared to the free enzyme at high temperatures (95 degrees C). Both glycogen and starch could be utilized by the immobilized enzyme, indicating that this technique could prove useful for starch hydrolysis. PMID:2112366

  5. Decolorization of two synthetic dyes using the purified laccase of Paraconiothyrium variabile immobilized on porous silica beads

    PubMed Central

    2014-01-01

    Background Decolorization of hazardous synthetic dyes using laccases in both free and immobilized form has gained attention during the last decades. The present study was designed to prepare immobilized laccase (purified from Paraconiothyrium variabile) on porous silica beads followed by evaluation of both free and immobilized laccases for decolorization of two synthetic dyes of Acid Blue 25 and Acid Orange 7. Effects of laccase concentration, pH and temperature alteration, and presence of 1-hydroxybenzotriazole (HBT) as laccase mediator on decolorization pattern were also studied. In addition, the kinetic parameters (K m and V max ) of the free and immobilized laccases for each synthetic dye were calculated. Results Immobilized laccase represented higher temperature and pH stability compare to free one. 39% and 35% of Acid Blue 25 and Acid Orange 7 was decolorized, respectively after 65 min incubation in presence of the free laccase. In the case of immobilized laccase decolorization percent was found to be 76% and 64% for Acid Blue 25 and Acid Orange 7, respectively at the same time. Increasing of laccase activity enhanced decolorization percent using free and immobilized laccases. Relative decolorization of both applied dyes was increased after treatment by laccase-HBT system. After nine cycles of decolorization by immobilized laccase, 26% and 31% of relative activity were lost in the case of Acid Blue 25 and Acid Orange 7, respectively. Conclusions To sum up, the present investigation introduced the immobilized laccase of P. variabile on porous beads as an efficient biocatalyst for decolorization of synthetic dyes. PMID:24393474

  6. Adaptation of Cancellous Bone to Aging and Immobilization in Growing Rats

    NASA Technical Reports Server (NTRS)

    Chen, Meng Meng; Jee, Webster S. S.; Ke, Hua Zhu; Lin, Bia Yun; Li, Qing Nan; Li, Xiao Jian

    1992-01-01

    Two-and-a half month-old female rats were subjected to right hindlimb immobilization or served as controls for 0, 1, 2, 8, 14, and 20 weeks. The right hindlimb was immobilized by bandaging it against the abdomen, thus unloading it. Cancellous bone histomorphometry was performed on microradiographs and double-fluorescent labeled 20 micron sections of the distal femoral metaphyses. Primary spongiosa bone loss occurred rapidly by 2 weeks, and secondary spongiosa bone loss occurred rapidly by 8 weeks of immobilization, and then equilibrated at 60% less bone mass than age-related controls. The negative bone balance induced by immobilization was caused by transient increase in bone resorption, decrease in bone formation, and longitudinal bone growth. The dynamic data of secondary spongiosa cancellous bone showed that percent eroded perimeter was transiently elevated by 55% to 82% between 1 and 8 weeks, percent labeled perimeter was transiently depressed by 32% to 50% between 1 and 14 weeks, mineral apposition rate was depressed by 23% and 19% at 1 and 2 weeks, and bone formation rate-bone area referent was transiently depressed by 35% and 59%c at 1 and 2 weeks. All the above parameters were at age-related control levels by 20 weeks of immobilization. However, bone formation rate-tissue area referent was depressed (-65%) throughout the study. Immobilization depressed completely longitudinal bone growth by 2 weeks and remained so. Only 0.65 mm of new metaphysis was generated in the immobilized versus 2.1 mm in controls during the study period. The immobilization induced an early cancellous bone loss which equilibrated at a new steady state with less bone and a normal (age-related control) bone turnover rate. When these findings were compared to an earlier study of 9 month-old virgin females subjected to right hindlimb immobilization up to 26 weeks, we found the adaptive responses of the cancellous bone were identical except that they occurred earlier and equilibrated

  7. Immobilization of peroxidase enzyme onto the porous silicon structure for enhancing its activity and stability

    NASA Astrophysics Data System (ADS)

    Sahare, Padmavati; Ayala, Marcela; Vazquez-Duhalt, Rafael; Agrawal, Vivechana

    2014-08-01

    In this work, a commercial peroxidase was immobilized onto porous silicon (PS) support functionalized with 3-aminopropyldiethoxysilane (APDES) and the performance of the obtained catalytic microreactor was studied. The immobilization steps were monitored and the activity of the immobilized enzyme in the PS pores was spectrophotometrically determined. The enzyme immobilization in porous silicon has demonstrated its potential as highly efficient enzymatic reactor. The effect of a polar organic solvent (acetonitrile) and the temperature (up to 50°C) on the activity and stability of the biocatalytic microreactor were studied. After 2-h incubation in organic solvent, the microreactor retained 80% of its initial activity in contrast to the system with free soluble peroxidase that lost 95% of its activity in the same period of time. Peroxidase immobilized into the spaces of the porous silicon support would be perspective for applications in treatments for environmental security such as removal of leached dye in textile industry or in treatment of different industrial effluents. The system can be also applied in the field of biomedicine.

  8. [Immobilization and characterization of carbonic anhydrase on the surface of hollow fiber membrane of polymethyl pentene].

    PubMed

    Wang, Qinmei; Zhang, Dihua; Zhang, Jingxia

    2009-07-01

    We immobilized carbonic anhydrase (CA) onto the surface of membrane oxygenator of polymethyl pentene (PMP) to enhance the removal of carbon dioxide in blood by two steps. We first introduced hydroxyl groups onto PMP surface by water plasma treatment, and then coupled CA onto PMP surface by using cyanate bromide (CNBr) as a crosslinker. After plasma treatment, the contact angle with water and chemical composition of PMP surface were characterized by analysis system of surface contact angle and XPS. Using p-nitrophenyl acetate (p-NPA) as a substrate, the activity, concentration, storage stability and re-usability of immobilized CA on PMP hollow fibers were studied by ultraviolet spectrophotometer. The preliminary data showed that hydroxyl groups could be introduced on the surface of PMP by water plasma treatment, and CA with catalysis activity could be successfully introduced onto PMP surface in high immobilization efficiency. The activity of covalently immobilized CA increased with the increase of concentration of CNBr, and the maximum was 73% of the theoretical activity of CA spread on PMP surface in monolayer in studied range. Covalently immobilized CA showed higher reusability compared to physically adsorbed CA, and higher storage stability compared to free CA in solution at 37 degrees C. The method would be used potentially in the membrane oxygenator to improve the capacity of removal of carbon dioxide in blood in the future. PMID:19835148

  9. Immobilization of the urease on eggshell membrane and its application in biosensor.

    PubMed

    D'Souza, S F; Kumar, Jitendra; Jha, Sandeep Kumar; Kubal, B S

    2013-03-01

    Eggshell membrane is a natural material, essentially made up of protein fibers having flexibility in the aqueous solution and possessing gas and water permeability. It is used as a biomembrane for immobilization of urease for the development of a potentiometric urea biosensor. Eggshell membrane was treated with polyethyleneimine (PEI) to impart polycation characteristics. Urease was immobilized on the PEI treated eggshell membrane through adsorption. SEM study was carried out to observe the changes in surface morphology after immobilization. FTIR study of membrane was carried out to observe the changes in IR spectra after immobilization of enzyme. Immobilized membrane was associated with ammonium ion selective electrode. Biosensor exhibited sigmoidal responses for the urea concentration range from 0.5 to 10mM. The response time of the biosensor was 120 s. A single membrane was reused for 270 reactions without loss of activity. The urease-eggshell membranes were stable for 2 months when stored in buffer even at room temperature. PMID:25427497

  10. Improvement of the stability and activity of immobilized glucose oxidase on modified iron oxide magnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Abbasi, Mahboube; Amiri, Razieh; Bordbar, Abdol-Kalegh; Ranjbakhsh, Elnaz; Khosropour, Ahmad-Reza

    2016-02-01

    Immobilized proteins and enzymes are widely investigated in the medical field as well as the food and environmental fields. In this study, glucose oxidase (GOX) was covalently immobilized on the surface of modified iron oxide magnetic nanoparticles (MIMNs) to produce a bioconjugate complex. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were used to the size, shape and structure characterization of the MIMNs. Binding of GOX to these MIMNs was confirmed by using FT-IR spectroscopy. The stability of the immobilized and free enzyme at different temperature and pH values was investigated by measuring the enzymatic activity. These studies reveal that the enzyme's stability is enhanced by immobilization. Further experiments showed that the storage stability of the enzyme is improved upon binding to the MIMNs. The results of kinetic measurements suggest that the effect of the immobilization process on substrate and product diffusion is small. Such bioconjugates can be considered as a catalytic nanodevice for accelerating the glucose oxidation reaction for biotechnological purposes.

  11. Immobilization of peroxidase enzyme onto the porous silicon structure for enhancing its activity and stability

    PubMed Central

    2014-01-01

    In this work, a commercial peroxidase was immobilized onto porous silicon (PS) support functionalized with 3-aminopropyldiethoxysilane (APDES) and the performance of the obtained catalytic microreactor was studied. The immobilization steps were monitored and the activity of the immobilized enzyme in the PS pores was spectrophotometrically determined. The enzyme immobilization in porous silicon has demonstrated its potential as highly efficient enzymatic reactor. The effect of a polar organic solvent (acetonitrile) and the temperature (up to 50°C) on the activity and stability of the biocatalytic microreactor were studied. After 2-h incubation in organic solvent, the microreactor retained 80% of its initial activity in contrast to the system with free soluble peroxidase that lost 95% of its activity in the same period of time. Peroxidase immobilized into the spaces of the porous silicon support would be perspective for applications in treatments for environmental security such as removal of leached dye in textile industry or in treatment of different industrial effluents. The system can be also applied in the field of biomedicine. PMID:25221454

  12. Effect of prior immobilization on muscular glucose clearance in resting and running rats

    SciTech Connect

    Vissing, J.; Ohkuwa, Tetsuo; Ploug, T.; Galbo, H. Nagoya Institute of Technology )

    1988-10-01

    In vitro studies have shown that prior disuse impairs the glucose clearance of red skeletal muscle because of a developed insensitivity to insulin. We studied whether an impaired glucose clearance is present in vivo in 42-h immobilized muscles of resting rats and, furthermore, whether the exercise-induced increase in glucose clearance of red muscles is affected by prior immobilization. The 2-({sup 3}H)deoxy-D-glucose (2DG) bolus injection method was used to determine glucose clearance of individual muscles. At rest, glucose clearance was markedly impaired in rats with previously immobilized red muscles compared with nonimmobilized control rats. During running, glucose clearance did not differ between muscles in previously immobilized and control rats. Insulin levels were always similar in the two groups and decreased during exercise. Intracellular nonphosphorylated 2DG was present in tissues with high glucose clearances. In conclusion, 42 h of immobilization markedly impairs glucose clearance of resting red muscle fibers in vivo. Apparently, physical inactivity in particular affects steps involved in insulin-mediated action that are not part of contraction-induced glucose uptake and metabolism. Presence of intracellular 2DG shows that separate determination of phosphorylated 2DG is necessary for accurate estimates of glucose metabolism and that accumulation of phosphorylated 2DG does not accurately reflect glucose transport.

  13. Polishing of POME by Chlorella sp. in suspended and immobilized system

    NASA Astrophysics Data System (ADS)

    Lahin, F. A.; Sarbatly, R.; Suali, E.

    2016-06-01

    The effect of using suspended and immobilized growth of Chlorella sp. to treat POME was studied. Cotton and nylon ropes were used as the immobilization material in a rotating microalgae biofilm reactor. The result showed that POME treated in suspended growth system was able to remove 81.9% and 55.5% of the total nitrogen (TN) and total phosphorus (TP) respectively. Whereas the immobilized system showed lower removal of 77.22% and 53.02% for TN and TP. Lower performance of immobilized microalgae is due to the limited light penetration and supply of CO2 inside the immobilization materials. The rotating microalgae biofilm reactor was able to reduce the biochemical oxygen demand (BOD) to 90 mg/L and chemical oxygen demand (COD) to 720 mg/L. Higher BOD and COD reading were obtained in suspended growth due to the presence of small number of microalgae cell in the samples. This study shows that suspended growth system is able to remove higher percentages of nitrogen and phosphorus. However, an efficient separation method such as membrane filtration is required to harvest the cultivated microalgae cell to avoid organic matter release into water bodies.

  14. Kinetic Characterization and Effect of Immobilized Thermostable β-Glucosidase in Alginate Gel Beads on Sugarcane Juice

    PubMed Central

    Keerti; Gupta, Anuradha; Dubey, Ashutosh; Verma, A. K.

    2014-01-01

    A thermostable β-glucosidase was effectively immobilized on alginate by the method of gel entrapment. After optimization of immobilized conditions, recovered enzyme activity was 60%. Optimum pH, temperature, kinetic parameters, thermal and pH stability, reusability, and storage stability were investigated. The Km and Vmax for immobilized β-glucosidase were estimated to be 5.0 mM and 0.64 U/ml, respectively. When comparing, free and immobilized enzyme, change was observed in optimum pH and temperature from 5.0 to 6.0 and 60°C to 80°C, respectively. Immobilized enzyme showed an increase in pH stability over the studied pH range (3.0–10.0) and stability at temperature up to 80°C. The storage stability and reusability of the immobilized β-glucosidase were improved significantly, with 12.09% activity retention at 30°C after being stored for 25 d and 17.85% residual activity after being repeatedly used for 4 times. The effect of both free and immobilized β-glucosidase enzyme on physicochemical properties of sugarcane juice was also analyzed. PMID:25969764

  15. Immobilization of saccharides and peptides on 96-well microtiter plates coated with methyl vinyl ether-maleic anhydride copolymer.

    PubMed

    Satoh, A; Kojima, K; Koyama, T; Ogawa, H; Matsumoto, I

    1998-06-15

    We have previously reported a method to immobilize protein ligands on microtiter plates coated with methyl vinyl ether-maleic anhydride copolymer (MMAC) [Isosaki, K., et al. (1992) J. Chromatogr. 597, 123-128]. In this study, we improved the MMAC method to efficiently immobilize not only small ligands such as peptides and oligosaccharides, which could not be efficiently immobilized previously, but also heparin via its reducing end. Amino and hydrazino groups were introduced to MMAC-coated microtiter plate wells by coupling to acid anhydride groups of MMAC with 1,6-hexamethylenediamine and adipic acid dihydrazide, respectively. The amino groups introduced were allowed to react with peptides by use of divalent cross-linkers. Hydrazino groups were allowed to react with formyl groups of saccharides by reductive amination. Peptides and oligosaccharides were immobilized in a dose-dependent manner by these methods. In the case of the angiotensin peptide thus immobilized, the detection limit by monoclonal antibodies was as low as 0.1-1 fmol peptide per well. Application of 20-200 nmol oligosaccharides to the well was sufficient to immobilize and subsequently detect lectins. Furthermore, heparin immobilized on the hydrazinocoated wells was successfully used for the binding assay of annexin IV. PMID:9648659

  16. Influence of chirality on catalytic generation of nitric oxide and platelet behavior on selenocystine immobilized TiO2 films.

    PubMed

    Fan, Yonghong; Pan, Xiaxin; Wang, Ke; Wu, Sisi; Han, Honghong; Yang, Ping; Luo, Rifang; Wang, Hong; Huang, Nan; Tan, Wei; Weng, Yajun

    2016-09-01

    As nitric oxide (NO) plays vital roles in the cardiovascular system, incorporating this molecule into cardiovascular stents is considered as an effective method. In the present study, selenocystine with different chirality (i.e., l- and d-selenocystine) was used as the catalytic molecule immobilized on TiO2 films for decomposing endogenous NO donor. The influences of surface chirality on NO release and platelet behavior were evaluated. Results show that although the amount of immobilized l-selenocystine on the surface was nearly the same as that of immobilized d-selenocystine, in vitro catalytic NO release tests showed that l-selenocystine immobilized surfaces were more capable of catalyzing the decomposition of S-nitrosoglutathione and thus generating more NO. Accordingly, l-selenocystine immobilized surfaces demonstrated significantly increased inhibiting effects on the platelet adhesion and activation, when compared to d-selenocystine immobilized ones. Measurement of the cGMP concentration of platelets further confirmed that surface chirality played an important role in regulating NO generation and platelet behaviors. Additionally, using bovine serum albumin and fibrinogen as model proteins, the protein adsorption determined with quartz crystal microbalance showed that the l-selenocystine immobilized surface enhanced protein adsorption. In conclusion, surface chirality significantly influences protein adsorption and NO release, which may have significant implications in the design of NO-generating cardiovascular stents. PMID:27153116

  17. Repeated immobilization stress alters rat hippocampal and prefrontal cortical morphology in parallel with endogenous agmatine and arginine decarboxylase levels

    PubMed Central

    Zhu, Meng-Yang; Wang, Wei-Ping; Huang, Jingjing; Feng, Yang-Zheng; Regunathan, Soundar; Bissette, Garth

    2008-01-01

    Agmatine, an endogenous amine derived from decarboxylation of L-arginine catalyzed by arginine decarboxylase, has been proposed as a neurotransmitter or neuromodulator in the brain. In the present study we examined whether agmatine has neuroprotective effects against repeated immobilization-induced morphological changes in brain tissues and possible effects of immobilization stress on endogenous agmatine levels and arginine decarboxylase expression in rat brains. Sprague-Dawley rats were subjected to two hour immobilization stress daily for seven days. This paradigm significantly increased plasma corticosterone levels, and the glutamate efflux in the hippocampus as measured by in vivo microdialysis. Immunohistochemical staining with β-tubulin III showed that repeated immobilization caused marked morphological alterations in the hippocampus and medial prefrontal cortex that were prevented by simultaneous treatment with agmatine (50 mg/kg/day, i.p.). Likewise, endogenous agmatine levels measured by high performance liquid chromatography in the prefrontal cortex, hippocampus, striatum and hypothalamus were significantly increased by immobilization, as compared to controls. The increased endogenous agmatine levels, ranging from 92% to 265% of controls, were accompanied by a significant increase of arginine decarboxylase protein levels in the same regions. These results demonstrate that administration of exogenous agmatine protects the hippocampus and medial prefrontal cortex against neuronal insults caused by repeated immobilization. The parallel increase in endogenous brain agmatine and arginine decarboxylase protein levels triggered by repeated immobilization indicates that the endogenous agmatine system may play an important role in adaptation to stress as a potential neuronal self-protection mechanism. PMID:18832001

  18. Influence of chirality on catalytic generation of nitric oxide and platelet behavior on selenocystine immobilized TiO2 films

    PubMed Central

    Fan, Yonghong; Pan, Xiaxin; Wang, Ke; Wu, Sisi; Han, Honghong; Yang, Ping; Luo, Rifang; Wang, Hong; Huang, Nan; Tan, Wei; Weng, Yajun

    2016-01-01

    As nitric oxide (NO) plays vital roles in the cardiovascular system, incorporating this molecule into cardiovascular stents is considered as an effective method. In the present study, selenocystine with different chirality (i.e., l- and d-selenocystine) was used as the catalytic molecule immobilized on TiO2 films for decomposing endogenous NO donor. The influences of surface chirality on NO release and platelet behavior were evaluated. Results show that although the amount of immobilized l-selenocystine on the surface was nearly the same as that of immobilized d-selenocystine, in vitro catalytic NO release tests showed that l-selenocystine immobilized surfaces were more capable of catalyzing the decomposition of S-nitrosoglutathione and thus generating more NO. Accordingly, l-selenocystine immobilized surfaces demonstrated significantly increased inhibiting effects on the platelet adhesion and activation, when compared to d-selenocystine immobilized ones. Measurement of the cGMP concentration of platelets further confirmed that surface chirality played an important role in regulating NO generation and platelet behaviors. Additionally, using bovine serum albumin and fibrinogen as model proteins, the protein adsorption determined with quartz crystal microbalance showed that the l-selenocystine immobilized surface enhanced protein adsorption. In conclusion, surface chirality significantly influences protein adsorption and NO release, which may have significant implications in the design of NO-generating cardiovascular stents. PMID:27153116

  19. Adaptive Postural Control for Joint Immobilization during Multitask Performance

    PubMed Central

    Hsu, Wei-Li

    2014-01-01

    Motor abundance is an essential feature of adaptive control. The range of joint combinations enabled by motor abundance provides the body with the necessary freedom to adopt different positions, configurations, and movements that allow for exploratory postural behavior. This study investigated the adaptation of postural control to joint immobilization during multi-task performance. Twelve healthy volunteers (6 males and 6 females; 21–29 yr) without any known neurological deficits, musculoskeletal conditions, or balance disorders participated in this study. The participants executed a targeting task, alone or combined with a ball-balancing task, while standing with free or restricted joint motions. The effects of joint configuration variability on center of mass (COM) stability were examined using uncontrolled manifold (UCM) analysis. The UCM method separates joint variability into two components: the first is consistent with the use of motor abundance, which does not affect COM position (VUCM); the second leads to COM position variability (VORT). The analysis showed that joints were coordinated such that their variability had a minimal effect on COM position. However, the component of joint variability that reflects the use of motor abundance to stabilize COM (VUCM) was significant decreased when the participants performed the combined task with immobilized joints. The component of joint variability that leads to COM variability (VORT) tended to increase with a reduction in joint degrees of freedom. The results suggested that joint immobilization increases the difficulty of stabilizing COM when multiple tasks are performed simultaneously. These findings are important for developing rehabilitation approaches for patients with limited joint movements. PMID:25329477

  20. Planarian Immobilization, Partial Irradiation, and Tissue Transplantation

    PubMed Central

    Guedelhoefer IV, Otto C.; Sánchez Alvarado, Alejandro

    2012-01-01

    cover the culture of large animals, immobilization, preparation for partial irradiation, tissue transplantation, and the optimization of animal recovery. Furthermore, the work described here demonstrates the first application of the partial irradiation method for use with the most widely studied planarian, Schmidtea mediterranea. Additionally, efficient tissue grafting in planaria opens the door for the functional testing of subpopulations of naïve or treated stem cells in repopulation assays, which has long been the gold-standard method of assaying adult stem cell potential in mammals8. Broad adoption of these techniques will no doubt lead to a better understanding of the cellular behaviors of adult stem cells during tissue homeostasis and regeneration. PMID:23007410