New Method For Immobilization Research Articles

Immobilization devices used to treat unusual sites for better radiation delivery: A single institutional experience

The present article illustrates an attempt to design and test the reproducibility of low-cost patient positioning devices prepared in-house in the radiotherapy department. A rigid wood-polymer composite material stands with angulations, scales, and support was designed as a new method for immobilization of the mobile target using a thermoplastic mask and a carbon fiber base plate. The lower mobile target, i.e., the penis of a patient, was immobilized by this method. A computed tomography simulation was performed for the patient. This device fit was suitable, comfortable, and had good reproducibility and repeatability, which was proven in daily radiotherapy. Reproducibility and accuracy were tested by serial electronic portal imaging detectors. The positioning devices showed variations within 2–3 mm on consecutive treatment days which were within acceptable limits. It is therefore concluded that low-cost patient positioning devices for the mobile target can be fabricated from available materials in-house. With the help of these in-house available materials, we can also fabricate other types of immobilization devices for particular techniques. It is considerably cheaper than commercially available products.

Coal Fly Ash as Raw Material for Immobilization of Sr-Contaminated Soil by Microwave Heating: Mechanism and Performance

In this work, coal fly ash, hereinafter CFA is proposed to work as raw material for immobilization of Sr-contaminated soil by microwave sintering in the path towards resource utilization of solid waste. The immobilization mechanism and performance was systemically investigated through phase evolution, microstructure, elemental distribution, and physical properties. The results shown that the Sr could be incorporated into feldspar strontian (SrAl2Si2O8) at 1300 °C for 30 min. Moreover, the maximum solid solubility of SrSO4 was more than 30 wt.%. The Sr was homogeneously distributed in the sintered matrices without substantial enrichment. The sintered matrix exhibited high density (2.53 g/cm3). Thus, microwave heating coupled with CFA could provide a new method for immobilization of Sr-contaminated soil in case of the spent nuclear reprocessing cycle in nuclear power plants or a nuclear accident emergency.

Nickel(II) complexes with tripodal NNN ligands as homogenous and supported catalysts for ethylene oligomerization

Four new coordination compounds of nickel (II) with derivatives of N,N-bis(pyrazol-1-ylmethyl)propylamine were synthesized; their composition and structure were confirmed with IR-spectroscopy and elemental analysis. The structures of products 13 and 15 were unambiguously established in an X-ray diffraction study. Compounds 13 and 15 crystallize in the orthorhombic space groups Pna21 and P212121 correspondingly and represent a monomeric octahedral nickel complexes, that are typical for tridentate scorpion-type ligands. New method for immobilization of nickel complexes with derivatives of N,N-bis(pyrazol-1-ylmethyl)propylamine on silica gel modified with aminopropyl groups was proposed. The EXAFS/XANES analysis indicated that Ni atom in the supported complexes adopt almost octahedral geometry, being partly surrounded by nitrogen atoms from organic ligand and partly grafted to silica surface through silanol groups, with Br− in outer coordination sphere. Both the original and the supported complexes, when activated with Et2AlCl or Et3Al2Cl3, catalyze ethylene oligomerization with the predominant formation of butene isomers. Generally, the immobilized complexes show higher activity and better selectivity towards 1-butene formation.

A New Method for Immobilization of His-Tagged Proteins with the Application of Low-Frequency AC Electric Field.

Continued advancement of protein array, bioelectrode, and biosensor technologies is necessary to develop methods for higher amount and highly oriented immobilization activity of proteins. In pursuit of these goals, we developed a new immobilization method by combining electrostatic transport and subsequent molecular diffusion of protein molecules. Our developed immobilization method is based on a model that transports proteins toward the substrate surface due to steep concentration gradient generated by low-frequency AC electric field. The immobilization of the maximum amounts can be obtained by the application of the AC voltage of 80 Vpp, 20 Hz both for His-tagged Green Fluorescent Protein (GFP) and Discosoma sp. Red Fluorescent Protein (DsRed), used as model proteins. The amounts of the immobilized His-tagged GFP and DsRed were approximately seven-fold higher than that in the absence of the application of low-frequency AC electric field. Furthermore, the positively and negatively charged His-tagged GFP at acidic and alkaline pH were immobilized by applying of low-frequency AC electric field, whereas the non-charged His-tagged GFP at the pH corresponding to its isoelectric point (pI) was not immobilized. Therefore, unless the pH is equal to pI, the immobilization of electrically charged proteins was strongly enhanced through electrostatic transport and subsequent molecular diffusion.

An optical sensor for determination of low pH values based on covalent immobilization of Congo red on triacetyl cellulose films via epichlorohydrin

A new method for immobilization of some indicators with amino groups on triacetyl cellulose beds was applied for construction of an optical sensor for measurement of low pH values. Congo red was used as a pH indicator which was immobilized covalently on triacetyl cellulose via epichlorohydrin. The response of the optical sensor to pH of the solutions was found to be 0–4.5. The effect of influencing parameters on activation of the hydrolyzed film by epichlorohydrin and also on the reaction of the activated film with the indicator was studied and they were optimized. Under optimum experimental conditions, the obtained results showed that the constructed optical sensor has a good repeatability, reproducibility, short term and long term stability (more than 9 months) and a relatively short response time (about 150s) for a relatively wide pH range.

Nickel Oxide Nanoparticles Immobilized on MWCNTs/PANI Composite Film as an Electron Transfer Facilitator for Horseradish Peroxidase: Direct Electron Transfer and H2O2 Determination

In this paper, we developed a new method for immobilization of horseradish peroxidase (HRP) on Nano-NiO/ MWCNTs/PANI composite film, which can effectively promote the direct electron transfer and electrocatalysis of enzyme in neutral solution. This composite film modified electrode was systematically investigated by altering the thickness of composite film, pH value of solution, and the mass ratio of MWCNT to NiO nanoparticles. The study showed that the effective immobilization of horseradish peroxidase on Nano-NiO/ MWCNTs/PANI was 30 cycles of cyclic voltammetry for the preparation of PANI film and the mass ratio of 10:1. The composite film possesses a high catalytic activity in pH 6.8 buffer solution containing H2O2. The plot of the response current to H2O2 concentration exhibited a linear relation at a range of 3.0 × 10−6 to 4.3 × 10−4 M, with a correlation coefficient of 0.998. The detection limit is 4.3 × 10−7 M(S/N = 3). These results indicated that the modified electrode was beneficial to retain the catalytic activity of the enzyme, and possessed good stability and reproducibility.

Application of forehead dot marking in radiotherapy for brain tumors

Objective To investigate the role of forehead dot marking in immobilization during radiotherapy for brain tumors. Methods A total of 84 patients with brain tumors were immobilized using the full-head mask from 2013 to 2014; among these patients, 36 received dot marking at the center of the forehead (group A), 27 received routine immobilization (group B), and 21 received dot marking at one side of the forehead (group C). Kilovoltage cone-beam computed tomography (CBCT) was used to compare the deviation in spatial position. The t-test was used to compare the deviation of the first CBCT in group A with the errors of subsequent CBCT. Results The passing rates of 212 times of CBCT in group A and 158 times of CBCT in group B were 95.2% and 93.8%. The errors in x, y, and z directions in groups A and B were 0.868±0.618 mm vs. 1.319±0.935 mm (P=0.005), 1.118±0.692 mm vs. 1.149±0.807 mm (P=0.824), and 0.868±0.790 mm vs. 0.936±0.919 mm (P=0.665). In group C, the error in the x direction was 1.162±0.866 mm, similar to those in groups A and B (P=0.070 and 0.430). In group A, the error in the x direction showed a difference between the first time and the sixth time (0.790±0.656 mm vs. 1.280±0.724 mm, P=0.030). Conclusions Compared with the routine technique, dot marking at the center of the forehead can improve the accuracy of positioning in the x direction and reduce rotation error, and provides a new method for immobilization in radiotherapy for brain tumors. Key words: Brain neoplasms/radiotherapy; Forehead dot marking; Set-up error

A New Method for Immobilization of NDHPI on SBA-15 Carrier Used as Catalyst for Selective Oxidation of Toluene

Mesoporous molecular sieve SBA-15 immobilized N,N-dihydroxypyromellitimide (NDHPI) was prepared by a new method, which was realized through the coupling NDHPI with pre-grafted glycidoxypropyl chains of glycidoxypropyl-SBA-15. SBA-15 immobilized N-hydroxyphthalimide (NHPI) by impregnation method was also prepared for comparison. The two catalysts were characterized by Fourier transform infrared spectroscopy, N2 adsorption–desorption technique, thermogravimetric analyses, X-ray diffraction, scanning electron microscope, transmission electron microscope and X-ray photoelectron spectroscopy. Then the catalysts and N,N-bis(salicylidene) ethylenediiminocobalt (Cosalen) complex were used into oxidation of toluene with molecular oxygen. The more active and reusable catalyst was the immobilized one coupled by NDHPI with glycidoxypropyl-SBA-15, which improved the total selectivity of benzaldehyde and benzyl alcohol to 46.0 % with the conversion of toluene 14.8 % at 90 °C for 7 h. Mesoporous molecular sieve SBA-15 immobilized N,N-dihydroxypyromellitimide (NDHPI) was prepared by a new method, which was realized through the coupling NDHPI with pre-grafted glycidoxypropyl chains of glycidoxypropyl-SBA-15. SBA-15 immobilized NHPI by impregnation method was also prepared for comparison. Their structure was characterized and their catalytic performance combined with Cosalen complex in the molecule oxidation of toluene were compared. Their reusability performance was also discussed.

A new method of lower extremity immobilization in radiotherapy

We developed a new method for immobilization of the fix lower extremities by using a thermoplastic mask, a carbon fiber base plate, a customized headrest, and an adjustable angle holder. The lower extremities of 11 patients with lower extremity tumors were immobilized by this method. CT simulation was performed for each patient. For all 11 patients, the device fit was suitable and comfortable and had good reproducibility, which was proven in daily radiotherapy.

Gold nanoparticle‐coated capillaries for protein and peptide analysis on open‐tubular capillary electrochromatography

We report a new method of immobilization of gold nanoparticles (AuNPs) on a fused-silica capillary through covalent binding. The resulting modified capillary was applied to electrophoretic systems to improve the efficiency of separation and the selectivity of selected solutes. The immobilization of AuNPs on the capillary wall was performed in a very simple and fast way without requiring heating. The surface features of an AuNP-coated capillary column were determined using the scanning electron microscopy. The chromatographic properties of AuNP-coated capillaries were investigated through variation of the buffer pH and separation voltage. Effective separations of synthetic peptides mixture were obtained on the AuNP-coated capillaries. The method shows a remarkable stability since it was reused about 900 times. The capacity factor was duplicated. Therefore, this modification is stable and can be applied to different separation purposes. A complex mixture of tryptic peptide fragments of HSA was analyzed in both the bare- and the AuNP-coated capillaries. Better electrophoretic peptide profile was observed when using the AuNP-coated capillary.

TiO 2/montmorillonite nanocomposite for removal of organic pollutant

In order to improve the adsorption and photocatalytic performance of TiO 2 modified clay composite, a new method of immobilization of nano-scaled TiO 2 on the layer surface of montmorillonite (MT) clay was designed and carried out in two steps in this work. The first step was to prepare a nano-scaled TiO 2 dispersion by a hydrothermal method with the addition of organic dispersant into an aqueous solution of TiCl 4; and then the assemblies of nano-scaled TiO 2 with CTAB (cetyltrimethylammonium bromide) were applied to regulate the process of immobilization of nano-scaled TiO 2 on the layer surface of MT clay. The results indicated that well pre-dispersed nano-TiO 2 was obtained with the application of diethanolamine (DEA) as a dispersant, which could interact with CTAB to form assemblies of nano-scaled TiO 2 particles and CTAB molecules (CTAB–DEA–TiO 2), and then became self-anchored on the layer surface of MT clay to produce well-distributed TiO 2/MT nanocomposites. After calcination at 500 °C, the modified composites showed much higher values for specific surface area, average pore size and pore volume than the raw MT clay. The adsorption and photocatalytic performance of the composite TCM-500 was evaluated by using methyl orange (MO). The comparative photocatalytic degradation of MO indicated that the composite gave 10% higher photocatalytic efficiency than P25 due to its optimal structural conformation tailored by surfactant assembly. Therefore, the new method of immobilization of pre-dispersed nano-scaled TiO 2 assembly with a surfactant was a good alternative to prepare a TiO 2/MT nanocomposite and was effective to improve its adsorption capacity and photocatalytic performance.

A New Strategy for Immobilization of Electroactive Species on the Surface of Solid Electrode

This letter reports on a new method for immobilization of electroactive species on a solid electrode surface based on the composite film of naphthol green B (NGB) and Co–Al layered double hydroxides (LDHs). After the oxidation potential of Co(III)/(II) couple was dramatically enhanced by NGB, the functionalized LDHs exhibited a remarkable electrocatalytic activity toward the oxidation of hydrazine in a weak acidic medium. The amperometric response to hydrazine showed a linear range of 0.17 μM–400 mM, with the calculated detection limit of 0.1 μM at a signal-to-noise ratio of three and the sensitivity of the amperometric hydrazine sensor was found to be 35.26 μA μM−1. The modified electrode displayed an acceptable reproducibility and good stability. The new strategy is expected to have wide applications for changing of the potential of redox couple in metal oxides, hydroxides, double hydroxides, and so on.

A New Method of Immobilization of Carbonic Anhydrase onto Polymer Surface without Active Functional Groups by Using SFAD as a Crosslinker

A New Method of Immobilization of Carbonic Anhydrase onto Polymer Surface without Active Functional Groups by Using SFAD as a Crosslinker

Use of gold nanoparticles for immobilization of L-cysteine on TLC plates

A new method of immobilization of the chiral selector on the surface of TLC plates by means of stepwise impregnation by gold nanoparticles and L-cysteine is described. The novel silica- and alumina-based stationary phases for TLC demonstrate enantioselectivity toward tetrahydrozoline, hydroxyzine, ketoprofen, fenoprofen, pindolol, and fluoxetine. The influence of the composition of the mobile phase on the Rf values and enantioselectivity is also discussed.

Immobilization of TiO2 nanoparticles on polymeric substrates by using electrostatic interaction in the aqueous phase

A new method for immobilization of TiO2 nanoparticles on polymeric substrates was developed to facilitate photocatalytic purification of contaminated air and water. TiO2 was immobilized by dipping a polymeric substrate, treated with polyvinyl chloride–polyvinyl acetate (PVC–PVA) copolymer and/or SiO2, into a TiO2/water suspension. The surface zeta potential measurement on TiO2 and treated polymers implies that this method is based on an electrostatic interaction between positively charged TiO2 and the negatively charged treated surface of the polymeric substrate. This method precludes the enwrapping of TiO2 particles in binding components, which has been a drawback of conventional methods, and enables bonding of the TiO2 nanoparticles on the substrate surface at high density. The TiO2-immobilized nonwoven polyester (PES) prepared using this method exhibited high photocatalytic activity for decomposing the air contaminant toluene. Furthermore, this method was applicable to polypropylene (PP) nonwoven, polyethylene (PE) nets and PE and PP films. TiO2 bonding was inhibited on PP by treatment with PVC–PVA copolymer and better TiO2 immobilization was observed on SiO2-treated PP.

A new method of immobilization of proteins on activated ester terminated alkanethiol monolayers towards the label free impedancemetric detection

This paper investigates a new immobilization procedure for biological molecules that is based on the formation of reactive ω-functionalized-self-assembled thiol monolayers onto a gold electrode. The homogeneous self-assembled monolayer was characterized by X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The SAM modified gold electrode showed a clear peak corresponding to S 2p that characterized the Au-thiolate bond, while cyclic voltammetry and electrochemical impedance spectroscopy measurements, in 10 mM phosphate buffer pH 7, in the presence of Fe(CN) 6 − 3/− 4 as redox probe, showed that these monolayers were densely packed and prevented electron transfer towards the gold surface. These homogeneous SAMs were used to immobilize biotin hydrazide by covalent attachment, after the nucleophilic attack of the amino group of biotin hydrazide on the ω-activated ester function of thiols. The biotin–avidin interaction was then examined as a model for an affinity biosensor with electrochemical impedance spectroscopy. A Randles equivalent circuit was used for the interpretation of impedance data and the change in the interfacial properties at the modified-electrode/electrolyte interface were monitored through charge-transfer resistance variation. The proposed affinity biosensor showed a detection range that was linear between 200 and 800 ng/ml for avidin. In order to improve the sensitivity the technique of mixed self-assembled monolayers was adopted. Mixed SAMs were elaborated by co-adsorption of two differently substituted thiols, one was substituted by a reactive group that was used to react with the amino group of biotin hydrazide, whereas the other was substituted by an hydroxyl group that was chosen to mimic protein resistance. In this study, we started with a 1:3 activated ester:hydroxyl-terminated alkanethiol ratio. The results obtained with the mixed SAMs appeared to be better than those obtained with the homogeneous SAMs, and the corresponding affinity biosensor presented two detection ranges that were linear between 20 and 100 ng/ml and between 100 and 1200 ng/ml, respectively, with two different slopes.

Tissue engineering with electric fields: Immobilization of mammalian cells in multilayer aggregates using dielectrophoresis

Positive dielectrophoresis can be used to create aggregates of animal cells with 3D architectures. It is shown that the cells, when pulled together into an aggregate by positive dielectrophoresis in a low-conductivity iso-osmotic solution, adhere to each other. The adherence of the cells to each other is non-specific and increases in time, and after 10-15 min becomes strong enough to immobilize the cells in the aggregate, enabling the ac electric field to be released, and the iso-osmotic buffer to be replaced by growth or other media. Cell viability is maintained. The new method of immobilization significantly simplifies the construction of aggregates of animal cells by dielectrophoresis, and increases the utility of dielectrophoresis in tissue engineering and related areas.

A new method for immobilization of acetylcholinesterase

A new method for immobilization of acetylcholinesterase (AChE) to alginate gel beads by activating the carbonyl groups of alginate using carbodiimide coupling agent has been successfully developed. Maximum reaction rate (V (max)) and Michaelis-Menten constant (K (m)) were determined for the free and binary immobilized enzyme. The effects of pH, temperature, storage stability, reuse number and thermal stability on the free and immobilized AChE were also investigated. For the free and binary immobilized enzyme on the Ca-alginate gel beads, optimum pH values were found to be 7 and 8, respectively. Optimum temperatures for the free and immobilized enzyme were observed to be 30 and 35 degrees C, respectively. Upon 60 days of storage the preserved activity of free and immobilized enzyme were found as 4 and 68%, respectively. In addition, reuse number, and thermal stability of the free AChE were increased by as a result of binary immobilization.

Ruhigstellung in Außenrotation bei primärer Schulterluxation

The standard method of treating acute primary dislocation of the glenohumeral joint is immobilization of the arm in adduction and internal rotation with a sling. The recurrence rate for anterior instability after nonoperative treatment in young active patients is extremely high (up to 90%) and well reported. A new method of immobilization with the arm in external rotation improves the position of the displaced labrum on the glenoid rim. With the use of control MRI before and after immobilization in external rotation, a study on this new repositioning of the labrum is evaluated. Ten patients (mean age 30.4 years) with primary anterior dislocation of the shoulder and Bankart lesion as shown on MRI but with no hyperlaxity of the contralateral side were immobilized in 10-20 degrees of external rotation for 3 weeks. Scans with MRI were taken in internal and external shoulder rotation post trauma and in internal rotation after 6 weeks. All patients were reevaluated after 6 and 12 months. Dislocation and separation of the labrum were both significantly less with the arm in external rotation due to the tension of the anterior capsule and the tendon of the subscapularis muscle. In the MRI taken in internal rotation 6 weeks post trauma, all Bankart lesions were fixed in reposition after three weeks of immobilization in external rotation. At 12-month follow-up, the average Constant Score was 96.1 points (range 63-100), and the Rowe Score was 91.5 points (range 25-100). One patient had traumatic redislocation after 8 months. After primary shoulder dislocation, immobilizing the arm in 10-20 degrees external rotation provided stable fixation of the Bankart lesion in an anatomic position. First long-term indications from an ongoing prospective study of recurrence rates after immobilization in external rotation are promising.

XPS and reactivity study of bimetallic nanoparticles containing Ru and Pt supported on a gold disk

We report a new method of immobilization of catalytic metal/alloy nanoparticles on a gold disk for transfer from an electrochemical cell to UHV (without sample exposure to air) for XPS analyses. Using this immobilization approach, several samples were examined: a core-shell Pt-on-Ru catalyst prepared from Ru black onto which Pt was spontaneously deposited, commercial Pt/Ru 50:50 nanoparticle alloy, as well as single metal Ru and Pt nanoparticle samples. The catalysts were characterized for the Ru oxidation state and for the methanol electrooxidation activity (as Pt was always metallic). For all bimetallic samples, we found that the reduced nanoparticles were more active towards methanol oxidation than the fully or partially oxidized samples. Regardless the Ru oxidation state however, the activity was lower than that previously reported for Ru decorated Pt nanoparticle catalysts (Ru-on-Pt). Possible reasons for the reactivity differences are discussed.