239 resultados para Micro-arc oxidation


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This work describes the fabrication of nanostructured copper electrodes using a simple potential cycling protocol that involves oxidation and reduction of the surface in an alkaline solution. It was found that the inclusion of additives, such as benzyl alcohol and phenylacetic acid, has a profound effect on the surface oxidation process and the subsequent reduction of these oxides. This results in not only a morphology change, but also affects the electrocatalytic performance of the electrode for the reduction of nitrate ions. In all cases, the electrocatalytic performance of the restructured electrodes was significantly enhanced compared with the unmodified electrode. The most promising material was formed when phenylacetic acid was used as the additive. In addition, the reduction of residual oxides on the surface after the modification procedure to expose freshly active reaction sites on the surface before nitrate reduction was found to be a significant factor in dictating the overall electrocatalytic activity. It is envisaged that this approach offers an interesting way to fabricate other nanostructured electrode surfaces.

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This book documents and evaluates the dramatic expansion of intellectual property law to accommodate various forms of biotechnology from micro-organisms, plants, and animals to human genes and stem cells. It makes a unique theoretical contribution to the controversial public debate over the commercialization of biological inventions. The author also considers the contradictions between the Supreme Court of Canada rulings in respect of the Harvard oncomouse, and genetically modified canola. He explores law, policy, and practice in both Australia and New Zealand in respect to gene patents and non-coding DNA. This study charts the rebellion against the European Union Biotechnology Directive – particularly in respect of Myriad Genetics’ BRCA1 and BRCA2 patents, and stem cell patent applications. The book also considers whether patent law will accommodate frontier technologies – such as bioinformatics, haplotype mapping, proteomics, pharmacogenomics, and nanotechnology. Intellectual Property and Biotechnology will be of prime interest to lawyers and patent attorneys, scientists and researchers, business managers and technology transfer specialists.

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In response to scientific breakthroughs in biotechnology, the development of new technologies, and the demands of a hungry capitalist marketplace, patent law has expanded to accommodate a range of biological inventions. There has been much academic and public debate as to whether gene patents have a positive impact upon research and development, health-care, and the protection of the environment. In a satire of prevailing patenting practices, the English poet and part-time casino waitress, Donna MacLean, sought a patent application - GB0000180.0 - in respect of herself. She explained that she had satisfied the usual patent criteria - in that she was novel, inventive, and useful: It has taken 30 years of hard labor for me to discover and invent myself, and now I wish to protect my invention from unauthorized exploitation, genetic or otherwise. I am new: I have led a private existence and I have not made the invention of myself public. I am not obvious (2000: 18). MacLean said she had many industrial applications. 'For example, my genes can be used in medical research to extremely profitable ends - I therefore wish to have sole control of my own genetic material' (2000: 18). She observed in an interview: 'There's a kind of unpleasant, grasping, greedy atmosphere at the moment around the mapping of the human genome ... I wanted to see if a human being could protect their own genes in law' (Meek, 2000). This special issue of Law in Context charts a new era in the long-standing debate over biological inventions. In the wake of the expansion of patentable subject matter, there has been great strain placed upon patent criteria - such as 'novelty', 'inventive step', and 'utility'. Furthermore, there has been a new focus upon legal doctrines which facilitate access to patented inventions - like the defence of experimental use, the 'Bolar' exception, patent pooling, and compulsory licensing. There has been a concerted effort to renew patent law with an infusion of ethical principles dealing with informed consent and benefit sharing. There has also been a backlash against the commercialisation of biological inventions, and a call by some activists for the abolition of patents on genetic inventions. This collection considers a wide range of biological inventions - ranging from micro-organisms, plants and flowers and transgenic animals to genes, express sequence tags, and research tools, as well as genetic diagnostic tests and pharmaceutical drugs. It is thus an important corrective to much policy work, which has been limited in its purview to merely gene patents and biomedical research. This collection compares and contrasts the various approaches of a number of jurisdictions to the legal problems in respect of biological inventions. In particular, it looks at the complexities of the 1998 European Union Directive on the Legal Protection of Biotechnological Inventions, as well as decisions of member states, such as the Netherlands, and peripheral states, like Iceland. The edition considers US jurisprudence on patent law and policy, as well as recent developments in Canada. It also focuses upon recent developments in Australia - especially in the wake of parallel policy inquiries into gene patents and access to genetic resources.

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Axillary shoots of Nicotiana benthamiana were regenerated from nodal explants in two weeks using MS media supplemented with the cytokinin, kinetin (0.5 mg/L), and the auxin, indole-3-butyric acid (IBA) (0.1 mg/L). Ninety two percent of shoots were 2.1-20 mm tall, a size ideal for root induction. After transfer to hormone-free MS they readily produced roots within seven days, with phenotypically normal, fully developed plants being obtained within four weeks. Leaf chlorosis due to iron deficiency was observed in plants over time, however, this was overcome by doubling the concentration of inorganic iron. This rapid micro-propagation system is particularly useful for the in vitro mass production of N. benthamiana plants for various biotechnological applications.

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Aerobic exercise training performed at the intensity eliciting maximal fat oxidation (Fatmax) has been shown to improve the metabolic profile of obese patients. However, limited information is available on the reproducibility of Fatmax and related physiological measures. The aim of this study was to assess the intra-individual variability of: a) Fatmax measurements determined using three different data analysis approaches and b) fat and carbohydrate oxidation rates at rest and at each stage of an individualized graded test. Fifteen healthy males [body mass index 23.1±0.6 kg/m2, maximal oxygen consumption () 52.0±2.0 ml/kg/min] completed a maximal test and two identical submaximal incremental tests on ergocycle (30-min rest followed by 5-min stages with increments of 7.5% of the maximal power output). Fat and carbohydrate oxidation rates were determined using indirect calorimetry. Fatmax was determined with three approaches: the sine model (SIN), measured values (MV) and 3rd polynomial curve (P3). Intra-individual coefficients of variation (CVs) and limits of agreement were calculated. CV for Fatmax determined with SIN was 16.4% and tended to be lower than with P3 and MV (18.6% and 20.8%, respectively). Limits of agreement for Fatmax were −2±27% of with SIN, −4±32 with P3 and −4±28 with MV. CVs of oxygen uptake, carbon dioxide production and respiratory exchange rate were <10% at rest and <5% during exercise. Conversely, CVs of fat oxidation rates (20% at rest and 24–49% during exercise) and carbohydrate oxidation rates (33.5% at rest, 8.5–12.9% during exercise) were higher. The intra-individual variability of Fatmax and fat oxidation rates was high (CV>15%), regardless of the data analysis approach employed. Further research on the determinants of the variability of Fatmax and fat oxidation rates is required.

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β-Hydroxyperoxyl radicals are formed during atmospheric oxidation of unsaturated volatile organic compounds such as isoprene. They are intermediates in the combustion of alcohols. In these environments the unimolecular isomerization and decomposition of β-hydroxyperoxyl radicals may be of importance, either through chemical or thermal activation. We have used ion-trap mass spectrometry to generate the distonic charge-tagged β-hydroxyalkyl radical anion, ˙CH2C(OH)(CH3)CH2C(O)O−, and investigated its subsequent reaction with O2 in the gas phase under conditions that are devoid of complicating radical–radical reactions. Quantum chemical calculations and master equation/RRKM theory modeling are used to rationalize the results and discern a reaction mechanism. Reaction is found to proceed via initial hydrogen abstraction from the γ-methylene group and from the β-hydroxyl group, with both reaction channels eventually forming isobaric product ions due to loss of either ˙OH + HCHO or ˙OH + CO2. Isotope labeling studies confirm that a 1,5-hydrogen shift from the β-hydroxyl functionality results in a hydroperoxyalkoxyl radical intermediate that can undergo further unimolecular dissociations. Furthermore, this study confirms that the facile decomposition of β-hydroxyperoxyl radicals can yield ˙OH in the gas phase.

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The reliability of micro inverters is an important factor as it would be necessary to reduce cost and maintenance of the small and medium scale distributed PV power conversion systems. Electrolytic capacitors and active power decouple circuits can be avoided in micro inverters with the use of medium voltage DC-link. Such a DC-link based micro inverter is proposed with a front-end dual inductor current-fed push-pull converter. The primary side power switches of the front-end converter have reduced switching losses due to multi-resonant operation. In addition, the voltage and current stresses on the diodes of the secondary diode voltage doubler rectifier are reduced due to the presence of a series resonant circuit in the front-end converter. The operation of the proposed micro inverter is explained using an in-depth analysis of the switching characteristics of the power semiconductor devices. The theoretical analysis of the proposed micro inverter is validated using simulation result.

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The “third-generation” 3D graphene structures, T-junction graphene micro-wells (T-GMWs) are produced on cheap polycrystalline Cu foils in a single-step, low-temperature (270 °C), energy-efficient, and environment-friendly dry plasma-enabled process. T-GMWs comprise vertical graphene (VG) petal-like sheets that seemlessly integrate with each other and the underlying horizontal graphene sheets by forming T-junctions. The microwells have the pico-to-femto-liter storage capacity and precipitate compartmentalized PBS crystals. The T-GMW films are transferred from the Cu substrates, without damage to the both, in de-ionized or tap water, at room temperature, and without commonly used sacrificial materials or hazardous chemicals. The Cu substrates are then re-used to produce similar-quality T-GMWs after a simple plasma conditioning. The isolated T-GMW films are transferred to diverse substrates and devices and show remarkable recovery of their electrical, optical, and hazardous NO2 gas sensing properties upon repeated bending (down to 1 mm radius) and release of flexible trasparent display plastic substrates. The plasma-enabled mechanism of T-GMW isolation in water is proposed and supported by the Cu plasma surface modification analysis. Our GMWs are suitable for various optoelectronic, sesning, energy, and biomedical applications while the growth approach is potentially scalable for future pilot-scale industrial production.

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This work aims to understand the influence of TiO2 surface structure in Au/TiO2 catalysts on CO oxidation. Au nanoparticles (3 wt%) in the range of 4 to 8 nm were loaded onto four kinds of TiO2 surfaces, which had different surface structures and were synthesized by calcining hydrogen titanate nanotubes at various temperatures and in different atmospheres. The Au catalyst supported on anatase nanorods exhibited the highest activity in CO oxidation at 30 °C among all the five Au/TiO2 catalysts including the reference catalyst of Au/TiO2-P25. X-ray photoelectron spectroscopy (XPS) and infrared emission spectra (IES) results indicate that the anatase nanorods have the most active surface on which water molecules can be strongly adsorbed and OH groups can be formed readily. Theoretical calculation indicates that the surface OH can facilitate the O2 adsorption on the anatase surface. Such active surface features are conducive to the O2 activation and CO oxidation

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This study compared fat oxidation rate from a graded exercise test (GXT) with a moderate-intensity interval training session (MIIT) in obese men. Twelve sedentary obese males (age 29 ± 4.1 years; BMI 29.1 ± 2.4 kg·m-2; fat mass 31.7 ± 4.4 %body mass) completed two exercise sessions: GXT to determine maximal fat oxidation (MFO) and maximal aerobic power (VO2max), and an interval cycling session during which respiratory gases were measured. The 30-min MIIT involved 5-min repetitions of workloads 20% below and 20% above the MFO intensity. VO2max was 31.8 ± 5.5 ml·kg-1·min-1 and all participants achieved ≥ 3 of the designated VO2max test criteria. The MFO identified during the GXT was not significantly different compared with the average fat oxidation rate in the MIIT session. During the MIIT session, fat oxidation rate increased with time; the highest rate (0.18 ± 0.11 g·min- 1) in minute 25 was significantly higher than the rate at minute 5 and 15 (p ≤ 0.01 and 0.05 respectively). In this cohort with low aerobic fitness, fat oxidation during the MIIT session was comparable with the MFO determined during a GXT. Future research may consider if the varying workload in moderate-intensity interval training helps adherence to exercise without compromising fat oxidation.

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A set of packed micro paddy lysimeters, placed in a greenhouse, was used to simulate the dissipation of two herbicides, simetryn and thiobencarb, in a controlled environment. Data from a field monitoring study in 2003, including the soil condition and water balances, were used in the simulation. The herbicides were applied and monitored over a period of 21 d. The water balances under two water management scenarios, intermittent irrigation management (AI) and continuous irrigation management (CI), were simulated. In the AI scenario, the pattern of herbicide dissipation in the surface water of the field were simulated, following the first-order kinetics. In the CI scenario, similarity was observed in most lysimeter and field concentrations, but there were differences in some data points. Dissipation curves of both herbicides in the surface water of the two simulated scenarios were not significantly different (P > 0.05) from the field data except for intercept of the thiobencarb curve in the CI scenario. The distribution of simetryn and thiobencarb in the soil profile after simulation were also similar to the field data. The highest concentrations of both herbicides were found on the topsoil layer at 0-2.5 cm depth. Only a small amount of herbicides moved down to the deeper soil layers. Micro paddy lysimeters are thus a good alternative for the dissipation study of pesticides in the paddy environment.

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The micro paddy lysimeter (MPL) was developed and evaluated for its performance to simulate solute transport in paddy environment under laboratory conditions. MPLs were constructed using soil collected from Field Museum Honmachi of Tokyo University of Agriculture and Technology, Japan. For the physical characteristics of the hardpan layer, parameters such as thickness, and soil aggregate size, affecting the percolation rate were studied. For the plow layer, two types of plow soils, sieved and un-sieved soils were compared. The sieved soil plow layer was produced by mixing air-dried soils of different aggregate sizes of D > 9.50, 9.50 ≥ D > 4.75, 4.75 ≥ D > 2.0 mm and D ≤ 2.0 mm at 47.1, 19.5, 20.6, and 12.8%, respectively. The un-sieved plow layer soil was directly used after collecting from the field. Inert tracer was applied to ponding water with controlled boundary conditions to evaluate the reproducibility of the soil hydraulic characteristics. HYDRUS-1D was used to evaluate the movement of bromide tracer in the MPL. The proposed conditions of the MPL were that the hardpan layer can be made from soil aggregates smaller than 0.425 mm with 2 cm thickness and that the plow layer can be prepared with sieved or un-sieved soils. With these conditions, the obtained results proved that MPLs can be a useful tool to simulate solute transport in paddy environment.

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The maintenance of genome stability is essential to prevent loss of genetic information and the development of diseases such as cancer. One of the most common forms of damage to the genetic code is the oxidation of DNA by reactive oxygen species (ROS), of which 8-oxo-7,8-dihydro-guanine (8-oxoG) is the most frequent modification. Previous studies have established that human single-stranded DNA-binding protein 1 (hSSB1) is essential for the repair of double-stranded DNA breaks by the process of homologous recombination. Here we show that hSSB1 is also required following oxidative damage. Cells lacking hSSB1 are sensitive to oxidizing agents, have deficient ATM and p53 activation and cannot effectively repair 8-oxoGs. Furthermore, we demonstrate that hSSB1 forms a complex with the human oxo-guanine glycosylase 1 (hOGG1) and is important for hOGG1 localization to the damaged chromatin. In vitro, hSSB1 binds directly to DNA containing 8-oxoguanines and enhances hOGG1 activity. These results underpin the crucial role hSSB1 plays as a guardian of the genome.

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We investigated the influence of different gas environments on the fabrication of surfaces, homogeneously covered with equally sized and spaced micro-structures. Two types of structures have been successfully micro-machined with a femtosecond laser on titanium surfaces in various atmospheres. The surface chemistry of samples machined in oxygen and helium shows TiO2, while machining in nitrogen leads to an additional share of TiN. The actual surface structure was found to vary significantly as a function of the gas environment. We found that the ablated particles and their surface triggered two consecutive events: The optical properties of the gas environment became non-isotropic which then led to the pulse intensity being redistributed throughout the cross section of the laser beam. Additionally, the effective intensity was further reduced for TiN surfaces due to TiN's high reflectivity. Thus, the settings for the applied raster-scanning machining method had to be adjusted for each gas environment to produce comparable structures. In contrast to previous studies, where only noble gases were found suitable to produce homogeneous patches, we obtained them in an oxygen environment.

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UNCITRAL Working Group I is presently developing a legal framework dealing with the entire lifecycle of Micro, Small and Medium Enterprises. The central focus of this work is to guide MSMEs in developing countries out of the grey economy and into the regulated, tax-paying space where these business will also have greater access to legitimate finance. Insolvency is an important, perhaps inevitable aspect of the life cycle of these enterprises. The question that is yet to be considered is a simplified insolvency regime for MSMEs. While the Working Group I is focused on the development of a model for developing economies, MSMEs in robust, highly developed economies also face particular challenges when faced with a solvency crisis. The present one-fits-all approach to insolvency requires a rethink.