Research progress on surface modification of titanium implants by strontium ions / 口腔疾病防治

@#Traditional titanium implants do not completely meet the clinical requirements because they are bioinert. The surface of titanium implants, modified by strontium ions, can enhance osseointegration and reduce peri-implantitis. In this paper, the biological properties of titanium implant surfaces modified by strontium ions were reviewed. Strontium ions can be coated on the implant surface by hydrothermal treatment, electrochemical deposition, phosphate chemical conversion, flame-spraying, supramolecular self-assembly, magnetron sputtering, laser deposition and alkali etching. Implant surfaces modified by strontium ions can not only promote osteogenesis and early osseointegration but also inhibit bacterial growth and reduce postoperative infections. Even better osseointegration and antibacterial effects can be achieved when strontium ions are incorporated with other elements, such as silver, zinc, gallium, and calcium. However, most of the studies on the use of strontium ion-modified titanium implants are animal experiments and in vitro experiments, and the observation time is short compared with the actual service life of the implants. Thus, the conclusions obtained may be different from the actual clinical application, and the long-term effects need to be studied. In addition, the osteogenic effects of various modification methods also need to be compared. Future research can focus on the following points: ① to find efficient modification methods that can be widely used in the clinic; ②to study how to control the concentration of strontium ions near the implant to exert their biological function and reduce their toxic side effects; and ③ to conduct long-term follow-up clinical trials to observe their osteogenic and antibacterial effects.

HYDROTHERMAL SYNTHESIS OF SPHERE-LIKE ZINC COBALTITE FOR ENERGY STORAGE DEVICES

The electrochemical performance of zinc cobaltite–based nano/micromaterial depends on its shape and morphology. Here we report on the electrochemical performance of zinc cobaltite (ZnCo O ) material synthesized via a facile 2 4 hydrothermal method. The synthesized material was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) analysis. It was found to be a single-phase zinc cobaltite material with a cubic spinel crystal structure. The electrochemical performance of the synthesized zinc cobaltite microstructure material was evaluated by cyclic voltammetry, cyclic chronopotentiometry and electrochemical impedance -1 -1 spectroscopy. The zinc cobaltite microspheres material displayed a high specific capacitance of 600.37 F g at a current density of 1 A g . Such electrochemical performance may qualify the zinc cobaltite microspheres material as a potential electroactive material in supercapacitors.

Preparation and antibacterial properties of a copper-niobium coating on a titanium surface by a microarc oxidation-microwave hydrothermal method / 口腔疾病防治

Objective@#To prepare a copper-nobium antibacterial coating on a titanium surface by a microarc oxidation-microwave hydrothermal two-step method and to study its surface structure and antibacterial properties.@*Methods@#Using titanium coated with a microarc oxidation coating (MAO group) as the substrate, copper and niobium were introduced by a microwave hydrothermal method in low (MHL-Cu group), medium (MHM-Cu group) and high (MHH-Cu group) copper chloride solutions and niobium oxalate (MH-Nb group) solutions, respectively. The component with the highest copper content was determined by energy spectrum analysis, and the copper-niobium composite coating (MH-Cu/Nb group) was prepared by microwave hydrothermal mixing with niobium oxalate. The microstructure, element distribution and phase composition of the specimens were characterized by scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction, and the bacteriostatic effect of the coating onEscherichia coliand Staphylococcus aureus was determined by the film method. @* Results@#Energy dispersive spectrometry showed that Cu was introduced onto the surface of the MHL-Cu, MHM-Cu, and MHH-Cu groups, and the atomic ratios of copper in each group were （0.68 ± 0.04）%,（1.17 ± 0.06）%, and （1.64 ± 0.03）%. The difference between groups was statistically significant (P< 0.01). Scanning electron microscopy showed a crater-like porous structure on the surface of the MAO group, and the MHL-Cu, MHM-Cu, MHH-Cu, MH-Nb, MH-Cu/Nb groups maintained micropore morphology. The roughness increased with increasing Cu2+ concentration, in which the MH-Nb and MH-Cu/Nb groups showed gully like structures simultaneously. X-ray diffraction showed that the coating of the MAO group was mainly composed of titanium and anatase phase TiO2, and the coatings of the MHL-Cu, MHM-Cu, MHH-Cu, MH-Nb, MH-Cu/Nb groups were mainly composed of anatase and rutile phase TiO2. Compared with the MAO group, Escherichia coli and Staphylococcus aureus in the MHH-Cu, MH-Nb, MH-Cu/Nb groups decreased to varying degrees, with significant differences (P< 0.001); compared with the MH-Cu/Nb group, the colony number difference had statistical significance (P> 0.05)@*Conclusion@#The rough, porous coating containing copper and niobium prepared by the microarc oxidation-microwave hydrothermal two-step method can effectively inhibit the growth ofEscherichia coli and Staphylococcus aureus.

Simple synthesis of photoluminescent carbon dots from a marine polysaccharide found in shark cartilage

BACKGROUND: For more than a decade, water-soluble, eco-friendly, biocompatible, and low-toxicity fluorescent nanomaterials have received considerable attention for their numerous in vivo and in vitro applications in biomedical imaging, disease diagnostics, and environmental monitoring. Owing to their tunable photoluminescence properties, carbon-based luminescent nanomaterials have shown great potential in bioimaging, photocatalysis, and biosensing among other applications. RESULTS: Marine environments provide excellent resources for the fabrication of these nanomaterials, because many marine organisms contain interesting trigger organic compounds that can be used as precursors. Herein, we synthesize multi-color emissive carbon dots (CDs) with an intrinsic photoluminescence quantum yield of 20.46%. These nanostructures were achieved through the one-step hydrothermal treatment of marine polysaccharide chondroitin sulfate, obtained from shark cartilage, in aqueous solution. CONCLUSIONS: We successfully demonstrate the low toxicity of our marine resource-derived CDs in zebrafish, and provide an initial assessment of their possible use as a bioimaging agent. Notably, the newly synthesized CDs localize in the intestines of zebrafish larvae, thereby indicating their biocompatibility and potential use as in vivo dyes.

Multiple target fishing hook prepared by photochemically coupling molecules in medicines onto magnetic nanoparticles / 中草药

Objective: To achieve multiple target fishing hook by efficiently grafting polymers containing benzophenone (BP) groups and photochemically coupling molecules in medicines onto magnetic nanoparticles (MNPs). Methods: MNPs attached carbonyl groups (Fe3O4-COOH) were prepared through a hydrothermal process. Then they were modified with DMSA, forming MNPs with thiol groups (Fe3O4-SH). Fe3O4-SH nanoparticles were grafted with polymer containing BP groups by surface-initiated condensation polymerization. Effects of monomer feed ratios and contents on the amounts of BP groups were investigated. The molecules in medicines were covalently coupled onto MNPs via photochemical reactions of BP groups. The contents of coupled molecules were determined by FT-IR and UV-Vis spectra analyses. Results: MNPs with average size of 100 nm were produced, modified with DMSA, and decorated by grafting polymer containing photosensitive BP groups. When the content of monomer containing BP groups was increased in grafting polymerizations, more BP groups were incorporated onto MNPs. This was conductive to the subsequent photo- coupling. FT-IR and UV-Vis spectra analyses confirmed the coupling of molecules in medicines. The active H and steric hinderance of the molecules affected their coupling. Conclusion: The resultant magnetic target fishing hook is ready as a probe for targets identification of traditional Chinese medicine (TCM).

Fabrication of rough surface on titanium using electrochemical treatment in NaCl electrolyte / 대한치과재료학회지

It is difficult to get sufficient roughness on titanium implant surface using traditional electrochemical treatments. In this study, we have developed a new method which provides a hybrid structured titanium surface having micro/nano roughness using electrochemical treatment in NaCl electrolyte and hydrothermal treatment. Titanium disks were anodically oxidized (ANO) in 0.15M NaCl electrolyte by applying positive electric pulses. The oxide compounds loosely attached to the surface were removed by ultrasonic cleaning (ANO group). These specimens were hydrothermally (HT) treated in an alkaline solution (ANO-HT group). ANO group showed the dimpled grain surfaces with a diameter of approximately 30 µm, and its roughness (Ra) was about 2.4 µm. The nano-sized crystallites which had an anatase TiO₂ crystalline structure were uniformly distributed on the surface of ANO-HT group. This group still retained high roughness (~2.7 µm) similar to ANO group and showed high hydrophilicity. Titanium surface with high roughness and hydrophilicity was fabricated using new electrochemical treating method and hydrothermal treatment. This surface modification method could be used for enhancing the osteoconductivity of the titanium implants.

Síntese hidrotérmica de zeólitas a partir de cinza volante de carvão mineral: aplicação na adsorção de íon amônio / Hydrothermal synthesis of zeolites from fly ash of mineral coal: application of ion ammonium adsorption

RESUMO A cinza volante é o principal resíduo industrial do uso de carvão mineral na geração de vapor e energia. No Brasil, são produzidas 1,4 milhão toneladas ao ano. Essas cinzas podem ser convertidas em produtos zeolíticos por tratamento hidrotérmico alcalino. Este trabalho teve como objetivo principal realizar essa conversão hidrotérmica, a fim de obter unicamente fases cristalinas zeolíticas para a adsorção de íon amônio. Realizaram-se diversas sínteses alterando o método utilizado (clássico ou de duas fases), o tempo de reação (24 ou 30 h) e a massa de NaOH. A caracterização dos produtos e da cinza (in natura e calcinada) foi realizada por difratometria de raios X, microscopia eletrônica de varredura e, em alguns casos, análises térmica diferencial e gravimétrica (ATD-TG). Os resultados demonstraram que é possível sintetizar as zeólitas hidroxissodalita e cancrinita a partir da cinza estudada. O produto obtido pelo método de duas etapas foi utilizado na adsorção de íon amônio em solução, sendo, neste processo, o modelo isotérmico de Sips o mais adequado; alcançando um valor de capacidade máxima de adsorção de 2,71 mg.g-1.

ABSTRACT Fly ash is the main industrial waste generated by coal in steam and power plans. In Brazil, 1,4 million tons are produced every year. These ashes can be converted into zeolite products by alkaline hydrothermal treatment. The main objective of this paper was to induce this reaction which produces only zeolitic crystalline phases for ammonium ion absorption. So, some syntheses were done by different hydrothermal method (classical or two stages), work time (24 or 30 h) and many NaOH bulks. The characterization of ash (in natura and calcined) and products was performed by X-ray diffraction method, scanning electron microscopy and, in some cases, differential thermal and thermogravimetric analysis The product by two stages method was used in ammonium ion absorption in solution at Sips Mathematic Model: the highest capacity of 2,71 mg.g-1.

Effect of grinding and aging on subcritical crack growth of a Y-TZP ceramic

Abstract This study aimed to investigate slow crack growth (SCG) behavior of a zirconia ceramic after grinding and simulated aging with low-temperature degradation (LTD). Complementary analysis of hardness, surface topography, crystalline phase transformation, and roughness were also measured. Disc-shaped specimens (15 mm Ø × 1.2 mm thick, n = 42) of a full-contour Y-TZP ceramic (Zirlux FC, Amherst) were manufactured according to ISO:6872-2008, and then divided into: Ctrl - as-sintered condition; Ctrl LTD - as-sintered after aging in autoclave (134°C, 2 bar, 20 h); G - ground with coarse diamond bur (grit size 181 μm); G LTD - ground and aged. The SCG parameters were measured by a dynamic biaxial flexural test, which determines the tensile stress versus stress rate under four different rates: 100, 10, 1 and 0.1 MPa/s. LTD led to m-phase content increase, as well as grinding (m-phase content: Ctrl - 0%; G - 12.3%; G LTD - 59.9%; Ctrl LTD - 81%). Surface topography and roughness analyses showed that grinding created an irregular surface (increased roughness) and aging did not promote any relevant surface change. There was no statistical difference on surface hardness among different conditions. The control group presented the lowest strength values in all tested rates. Regarding SCG, ground conditions were less susceptible to SCG, delaying its occurrence. Aging (LTD) caused an increase in SCG susceptibility for the as-sintered condition (i.e. G < G LTD < Ctrl < Ctrl LTD).

Effect of several repair techniques on the bond strength between composite resin and degraded Y-TZP ceramic / Efeito de várias técnicas de reparo na resistência de união entre resina composta e zircônia degradada

Objective: To evaluate the bond strength of different repair treatments for composite resin to aged Y-TZP ceramics. Material and Methods: Zirconia blocks were cut into smaller specimens, sintered according to manufacturer's recommendations (final dimensions of 4×4×3 mm), and randomly allocated into nine groups (n=15) according to the surface treatment and presence/ absence of aging of the substrate (subjected to lowtemperature degradation - LTD), as follows: without LTD (Control: without treatment; TBS: tribochemical silica coating + silane + adhesive); with LTD (Control-LTD: without treatment; TBS-LTD: TBS with hydrothermal degradation; MoS-LTD: Monobond S + adhesive; MoPLTD: Monobond Plus + adhesive; MZP-LTD: Metal/ Zirconia Primer + adhesive; USB-LTD: Single Bond Universal; AP-LTD: Alloy primer + adhesive). LTD was simulated in an autoclave (134 °C, 2 bar, 5 h). The ceramic blocks were embedded in PVC cylinders with a self-curing acrylic resin; each surface treatment protocol was performed; a composite resin cylinder ( : 3.25 mm and height: 3 mm) was then build-up using split metallic matrices. All the specimens were aged (thermocycling + storage in water for 90 days) and subjected to the shear bond strength test using a universal testing machine (1 mm/min). The failure mode was classified into four types: adhesive, composite resin cohesive fracture, ceramic cohesive fracture, and mixed. The bond strength values were subjected to Mann­Whitney test. Results: Only air-abraded samples (TBS and TBS­LTD) survived thermocycling. More than 80% of the samples of the other groups presented pre-test failures. TBS groups presented higher values of bond strength (3.94) compared to TBSLTD (0.96). The predominant type of failure for the surviving samples were adhesive. Conclusion: Air particle abrasion is mandatory to improve the bond strength of the Y-TZP substrate; an aged substrate presents an even more unfavorable scenario for adhesion. (AU)

Objetivo: Avaliar a resistência de união ao cisalhamento gerada por diferentes técnicas de reparo em resina composta aderida em zircônia envelhecida (sujeita a degradação a baixa temperatura - LTD). Material e Métodos: blocos de zircônia foram seccionados em espécimes, sinterizados de acordo com o fabricante (dimensões finais de 4x4x3 mm), e aleatorizados em nove grupos (n=15) de acordo com o tratamento de superfície e presença/ausência de envelhecimento do substrato (LTD), conforme: sem LTD (Control: sem tratamento; TBS: tribosilicatização + silano + adesivo); com LTD (Control-LTD: Monobond S + adesivo; MoP-LTD: Monobond plus + adesivo; MZPLTD: Meta/Zirconia primer + adesivo). LTD foi simulada em autoclave (134 °C, 2 bar, 5 h). Os blocos de cerâmica foram embutidos em cilindros de PVC com resina acrílica autopolimerizável; cada tratamento de superfície foi realizado; um cilindro de resina composta ( : 3,25 mm 3 mm de altura) foi confeccionado usando matrizes metálicas bipartidas. Todos os espécimes foram envelhecidos (termociclagem + armazenagem em água por 90 dias) e sujeitos ao teste de cisalhamento usando um equipamento de teste universal (1 mm/ min). O modo de falha foi classificado em quatro grupos: adesivo, fratura coesiva em resina composta, fratura coesiva da cerâmica, e mista. Os valores de adesão foram sujeitos ao teste de Mann-Whitney. Resultados: somente as amostras jateadas (TBS e TBSLTD) sobreviveram a termociclagem. Mais que 80% dos espécimes dos outros grupos apresentaram falhas préteste. Os grupos TBS apresentaram os maiores valores de resistência ao cisalhamento (3,94) comparado com TBS-LTD (0,96). Os tipos predominantes de falha para os espécimes sobreviventes foi adesiva. Conclusão: o jateamento é recomendável para aumentar a resistência adesiva à zircônia; um substrato envelhecido apresenta um cenário mais desfavorável de adesão. (AU)

Green, Low-cost Ball Milling-Hydrothermal Synthesis ofGraphene Quantum Dots and Applications / 分析化学

A ball milling method which is green with simple-manipulation and low-cost was used to prepare graphene as precursor for graphene quantum dots (GQDs) synthesis.Subsequently, GQDs with good dispersibility, uniform size distribution, average diameter of (4.80 ± 0.20) nm and 1-3 layers were prepared by one-step hydrothermal method.The morphology, structure and optical properties of the GQDs were characterized by high-resolution transmission electron microscopy (HRTEM), atomic force microscope (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), UV-Vis absorption and fluorescence spectroscopy.Furthermore, the GQDs were used in label-free and specific detection of ferric ion (Fe.3+) with broad linear ranges of 2.0×10.-6-7.0×10.-4 mol/L and low detection limit of 1.8 × 10.6 mol/L (S/N=3).The possible mechanism was also discussed and the application of GQDs for Fe.3+ detection in tap water was demonstrated.Finally, based on their low cytotoxicity and excellent biocompatibility, the as-prepared GQDs were successfully applied to efficient cell imaging.This work provides a new way for preparation of carbon-based nanomaterials and build a foundation for deepening applications of GQDs in bio-/chem-analysis, bioimaging, etc.

Characteristics Analysis of Metal Elements in Sediments and Habitat Mussels from India Ocean Hydrothermal Area / 分析化学

The concentrations and distributions of trace metals and rare earth elements (REE) in sediment and mussel samples collected from the India Ocean hydrothermal area were analyzed.The metal correlation between organisms and sediments was investigated, and the ecological and chemical characteristics of REE were also explored.The results showed that, the trace metals in sediments were mainly Fe (96.6 mg/kg), Mn (1.14 mg/kg) and Zn (322.6 μg/kg), and Fe had high ratio of 98.15% by normalized calculation, which indicated that the available sediments in this studying hydrothermal area mainly consisted of iron ore substances.Trace metals and REE distributions all had good correlation between deep-sea sediments and deep-sea mussels, and the correlation coefficients were 0.991 for trace metals and 0.996 for REE.The contents and distributions of metal elements in deep-sea mussels were different from those in offshore mussels.The REE distributions in sediments and mussels showed obvious fractionation phenomenon, and the enrichment of LREE in mussels was significant.Through the REE patterns, Eu and Gd in sediments and mussels all showed anomalies, and Eu had a significant abnormal phenomenon in deep-sea sediments and deep-sea mussels.Besides, δEu values were 9.50, 10.68 and 0.23 in deep-sea sediments, deep-sea mussels and offshore mussels, respectively, and δCe were 2.21, 2.71 and 4.38, which showed that the enrichment sources of REE in offshore mussels and deep-sea mussels were different, and the REE in sediments and mussels from the India Ocean were homologous.

Synthesis of Novel Water-Soluble Silicon Quantum Dots with Imidazole Groups and Its Application in Fluorescent Detection of / 分析化学

Silicon quantum dot has become an attractive nanomaterial due to their excellent biocompatibility and optical performance. However, poor water-solubility of the traditional silicon quantum dot limits its wide application. In this study, we reported the synthesis of water-soluble silicon quantum dots with imidazole groups by using hydrothermal method, in which N-trimethysilylimidazole was used as a precursor of silicon. Compared with sodium borohydride, ascorbic acid, bovine serum protein, cysteine and citric acid, the as-prepared silicon quantum dots offered the strongest fluorescence intensity when sodium citrate was used as the reducing agent and stabilizer for the synthesis. The reaction could complete within 2 h at 220℃. The obtained silicon quantum dots showed good water-solubility with an average particle size of 2. 6 nm, and the result of infrared spectroscopic analysis verified the existence of free imidazole groups on the surface. By means of the investigation of the fluorescence quenching behavior of copper ions towards the silicon quantum dots at different temperatures, we found that the degree of fluorescence quenching increased with the increase of temperature. There results proved that the fluorescence decrease belongs to static quenching. Namely, the interaction of Cu2+ with imidazole groups on the surface of silicon quantum dots formed stable complex. In addition, the resonance light scattering analysis also showed that the fluorescence quenching process was accompanied by the agglomeration of particles. Based on the fluorescence quenching behavior of silicon quantum dots, we established a method for the fluorescent detection of Cu2+. When the concentration of Cu2+was in the range of 0. 04-2400 μmol/L, the fluorescence intensity would linearly decrease with the increase of Cu2+ concentration, and the detection limit (S/N=3) reached 1. 29×10-8 mol/L. The method provided high sensitivity, selectivity and reproducibility, and was successfully applied to the determination of trace copper in fruits and vegetables.

Effect of Hydrothermal Treatment on Macro/Micro Nutrients Extraction from Chicken Manure for Liquid Organic Fertilizer Production.

In order to study the influence of the hydrothermal treatment technology (HTT) on macro/micro nutrients extraction from two types of chicken manure (broiler chicken manure (BCM) and laying hen chicken manure (LCM)), hydrothermal treatment followed by the solid/liquid separation of the HTT product was performed with a fixed feedstock to water mass ratio (1:3), 30 min reaction time and three different reaction temperatures (160ºC, 180ºC, 200ºC). More than 50% of N can be extracted from solid to liquid after HTT for both BCM and LCM. Moreover, the organic N content was more than 80% in all liquid samples and it was increasing with the increase of HTT temperature. According to all the results, 180ºC is the optimum temperature for both types of chicken manure and the pH value of the liquid extracted at the optimum temperature was close to 7 for both types of chicken manure. The heavy metal contents in the liquid obtained from BCM and LCM were not detected. It was observed that macro nutrients and micro-nutrients were dissolved in the liquid after HTT.

Effects of Liquid Fertilizer Produced from Sewage Sludge by the Hydrothermal Process on the Growth of Komatsuna.

The objective of this study is to evaluate the possibility of recycling the liquid product obtained from sewage sludge by the hydrothermal treatment as a kind of organic fertilizer and its effect on the plant growth. A small scale hydrothermal treatment experiment was performed and proved that the liquid product contains high content of nitrogen and low content of micronutrients. Therefore, the liquid product has the potential to be used as a kind of liquid fertilizer. In a seed germination test, the liquid product indicated low phytotoxicity. Moreover, in a Komatsuna cultivation experiment, the liquid product showed accelerate effect to the crop yield which is not lower than the chemical fertilizer. Through the low-temperature hydrothermal treatment, the sewage sludge was converted into liquid organic material that could be used as a delayed-release nitrogen fertilizer for the growth of Komatsuna. These results indicated the possibility of establishing a comprehensive system for recycling sewage sludge into a kind of organic fertilizer.

Hydrothermal treatment and Mesoporosity of MCM-41 mesoporous nanocomposite.

Considerable research efforts have been made in recent years towards the development of silica mesoporous nanocomposite as drug delivery system. Numerous reports are available in literature for the synthesis of mesoporous nano materials. In present work two distinct mesoporous MCM-41 nanocomposite (MCM-41-A and MCM-41-B) were synthesized and characterized by different instrumental techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, FTIR and nitrogen adsorption desorption analyses. Both the mesoporous nanocomposite was synthesized with different hydrothermal treatment and effect on mesoporosity was determined. Evaluation data revealed MCM-41-A MSNs with regular spherical shape with high degree of mesoporosity whereas MCM-41-B MSNs were lack of mesoporous characteristics. For instance, hydrothermal treatment significantly affects the physical properties like surface area, pore volume and pore diameter of the MSNs.

Preparation of hydroxyapatite in the presence of amino acids by hydrothermal method / 国际生物医学工程杂志

Objective To investigate the preparation method of hydroxyapatite by amino acids induced hydrothermal technique.Methods The hydroxyapatite nanorods were obtained using alanine and glycine as templates by hydrothermal method.The samples were characterized by X-ray diffraction (XRD),Fourier infrared spectroscopy (FTIR),transmission electron microscopy (TEM).Results The results showed that amino acids induced the formation of hydroxyapatite.Amino acids could affect crystallinity and dispersion of the formed hydroxyapatite.In addition,the substituent content of carbonate ions in hydroxyapatite was reduced by changing the ratio of amino acids.Conclusion Hydroxyapatite with high crystallinity and low carbonate ions can be prepared by hydrothermal method in the presence of amino acids.

Preparation of Electrophoretic Microcolumn Packed with Quartz Microncrystal and Its Application to Electrophoretic Separation / 分析化学

The preparation of electrophoretic microcolumn and its application to the electrophoretic separation of amino acids with a 2-mm I.D. fused-silica microcolumn packed with uniform quartz microncrystal prepared by hydrothermal synthesis are reported. With 1.5 mmol/L disodium phosphate buffer solution (pH 11.5) containing 30% (V/V) methanol, the tryptophan, phenylalanine and tyrosine were separated by the microcolumn electrophoresis and detected by an UV spectrophotometer without derivatization. The limits of detection were 0.038, 0.21 and 0.20 mol/L, respectively. The separation efficiency of tryptophan was 4.4×104 plates/m. The sample capacity of the electrophoretic microcolumn achieved 35 μL. The precisions of the microcolumn electrophoresis were satisfactory. The thermal effects of the electrophoretic microcolumn that without packing, packed with 360 μm quartz sand and with 9 μm length quartz microncrystal were discussed, respectively. It was found that the electrophoretic microcolumn packed with quartz microncrystal was able to inhibit Joule heat, increase sample capacity and enhance detection sensitivity. The microcolumn electrophoresis is one of the high-performance separation techniques for an in-situ, real-time and portable electrokinetic flow analysis system.

Preparation of TiO2 Nano-materials and Photocatalytic Purification of Sewage / 环境与健康杂志

The recent research progress of photo-catalyzed degradation of organic pollutants by TiO2 is reviewed,the characteristics of hydrothermal method and the prepared processes of TiO2 were discussed,the photo-catalyzed mechanism under UV and visible light and the application of degradation of sewage using TiO2 nanomaterials from five aspects were described in this paper. The main problems existing in the studies of TiO2,the research directions,and the development prospects were also discussed.

Modificaciones ee las propiedades texturales y structurales de una zeolita usyy y de sus mezclas con "caolín clay" y clorhidrol como consecuencia del tratamiento hidrotérmico / Modifications of the textural and structural proprties of zeolite usy and its miixture with kaolin clay and chlorhydrol as consequence of the hydrothermal treatment

El catalizador de FCC está constituido por partículas de composición compleja donde el componente activo es una zeolita Y. En este trabajo se presentan los resultados texturales y estructurales de una zeolita USY comercial lixiviada, de una serie de catalizadores con 7, 15, 25, 35 y 45% de material activo y los de estos materiales desactivados hidrotérmicamente. Las muestras se caracterizaron por fluorescencia de rayos X (FRX), difracción de rayos X (DRX), resonancia magnética nuclear de silicio (29Si RMN) y fisiadsorción de nitrógeno a 77 K. A partir de estos resultados se hallaron correlaciones entre el volumen de microporo y el contenido de zeolita y entre el grado de cristalinidad y el porcentaje de zeolita. Además, se encontró que un tratamiento con sólo 20% de vapor de agua a 1033 K durante 16 horas destruye los grupos estructurales Si(2Al) y Si(3Al) como reflejo de la dealuminización drástica que sufre el material.

FCC catalyst is made up of particles of complex composition where the main active component is a Y zeolite. This work presents the textural and structural results of a commercial USY zeolite which had been previously prepared from a set of catalysts with 7, 15, 25, 35 y 45% of active material and of the hydrothermally deactivated materials zeolite. The samples have been characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), 29Si NMR spectroscopy and nitrogen adsorption at 77K. From these results was found correlations between micropore volume and zeolite content and degree crystallinity and %zeolite. Also, it was found that an hydrothermal treatment at 1033 K with only 20% steam during 16 hours destroys the structural groups Si(2Al) and Si(3Al) as a reflection of the strongly dealumination of the zeolite component of the catalyst.

Study on the enhancing micro-roughness of porous surfaced dental implant through anodization / 대한치과보철학회지

STATEMENT OF PROBLEM: HA has been used as a coating material on Ti implants to improve osteoconductivity. However, it is difficult to form uniform HA coatings on implants with complex surface geometries using a plasma spraying technique. PURPOSE: To determine if Ti6Al4V sintered porous-surfaced implants coated with HA solgel coated and hydrothermal treated would accelerate osseointegration. MATERIALS AND METHODS: Porous implants which were made by electric discharge were used in this study. Implants were anodized and hydrothermal treatment or HA sol-gel coating was performed. Hydrothermal treatment was conducted by high pressure steam at 300 degrees C for 2 hours using a autoclave. To make a HA sol, triethyl phosphite and calcium nitrate were diluted and dissolved in anhydrous ethanol and mixed. Then anodized implant were spin-coated with the prepared HA sols and heat treated. Samples were soaked in the Hanks' solution with pH 7.4 at 37 degrees C for 6 weeks. The microstructure of the specimens was observed with a scanning electron microscope (SEM), and the composition of the surface layer was analyzed with an energy dispersive spectroscope (EDS). RESULTS: The scanning electron micrographs of HA sol-gel coated and hydrothermal treated surface did not show any significant change in the size or shape of the pores. After immersion in Hanks' solution, the precipitated HA crystals covered macro- and micro-pores. The precipitated Ca and P increased in Hanks' solution that surface treatment caused increased activity. CONCLUSION: This study shows that sol-gel coated HA and hydrothermal treatment significantly enhance the rate of HA formation due to the altered surface chemistry.