Search results for: fluorescence in situ hybridization

Authors: Erwan Negre, Ewan J. O'Connor, Juha Toivonen

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The need for CO2 monitoring technologies grows simultaneously with the worldwide concerns regarding environmental challenges. To that purpose, we developed a compact coherent all-fiber ranged-resolved Differential Absorption Lidar (RR-DIAL). It has been designed along a tunable 2x1fiber optic switch set to a frequency of 1 Hz between two Distributed FeedBack (DFB) lasers emitting in the continuous-wave mode at 1571.41 nm (absorption line of CO2) and 1571.25 nm (CO2 absorption-free line), with linewidth and tuning range of respectively 1 MHz and 3 nm over operating wavelength. A three stages amplification through Erbium and Erbium-Ytterbium doped fibers coupled to a Radio Frequency (RF) driven Acousto-Optic Modulator (AOM) generates 100 ns pulses at a repetition rate from 10 to 30 kHz with a peak power up to 2.5 kW and a spatial resolution of 15 m, allowing fast and highly resolved CO2 profiles. The same afocal collection system is used for the output of the laser source and the backscattered light which is then directed to a circulator before being mixed with the local oscillator for heterodyne detection. Packaged in an easily transportable box which also includes a server and a Field Programmable Gate Array (FPGA) card for on-line data processing and storing, our setup allows an effective and quick deployment for versatile in-situ analysis, whether it be vertical atmospheric monitoring, large field mapping or sequestration site continuous oversight. Setup operation and results from initial field measurements will be discussed.

Keywords: CO2 profiles, coherent DIAL, in-situ atmospheric sensing, near infrared fiber source

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Authors: Rabea Sefrin, Christian Glock, Juergen Schnell

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The preservation of existing structures is of great economic interest because it contributes to higher sustainability and resource conservation. In the case of existing buildings, in addition to repair and maintenance, modernization or reconstruction works often take place in the course of adjustments or changes in use. Since the structural framework and the associated load level are usually changed in the course of the structural measures, the stability of the structure must be verified in accordance with the currently valid regulations. The concrete compressive strength of the existing structures concrete and the derived mechanical parameters are of central importance for the recalculation and verification. However, the compressive strength of the existing concrete is usually set comparatively low and thus underestimated. The reasons for this are too small numbers, and large scatter of material properties of the drill cores, which are used for the experimental determination of the design value of the compressive strength. Within a structural component, the load is usually transferred over the area with higher stiffness and consequently with higher compressive strength. Therefore, existing strength variations within a component only play a subordinate role due to rearrangement effects. This paper deals with the experimental and numerical determination of such rearrangement effects in order to calculate the concrete compressive strength of existing structures more realistic and economical. The influence of individual parameters such as the specimen geometry (prism or cylinder) or the coefficient of variation of the concrete compressive strength is analyzed in experimental small-part tests. The coefficients of variation commonly used in practice are adjusted by dividing the test specimens into several layers consisting of different concretes, which are monolithically connected to each other. From each combination, a sufficient number of the test specimen is produced and tested to enable evaluation on a statistical basis. Based on the experimental tests, FE simulations are carried out to validate the test results. In the frame of a subsequent parameter study, a large number of combinations is considered, which had not been investigated in the experimental tests yet. Thus, the influence of individual parameters on the size and characteristic of the rearrangement effect is determined and described more detailed. Based on the parameter study and the experimental results, a calculation model for a more realistic determination of the in situ concrete compressive strength is developed and presented. By considering rearrangement effects in concrete during recalculation, a higher number of existing structures can be maintained without structural measures. The preservation of existing structures is not only decisive from an economic, sustainable, and resource-saving point of view but also represents an added value for cultural and social aspects.

Keywords: existing structures, in-situ concrete compressive strength, rearrangement effects, recalculation

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Authors: Mateusz Kudasik, Katarzyna Kozieł

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The work included detailed studies of CO₂/CH₄ exchange on a shale core from the Lewino-1G2 well (Poland) from a depth of 3408 m. The sample permeability coefficients were determined under conditions of confining pressure from 5 MPa to 35 MPa. These studies showed that at a confining pressure of 35 MPa – corresponding to a depth of about 1000 m, the shale core was impermeable in the direction perpendicular to the bedding, and in the direction parallel to the bedding, the sample had very low permeability (k∞=0.001 mD). The sorption tests performed showed low sorption capacities, which amounted to a maximum of 1.28 cm³/g in relation to CO₂ and 0.87 cm³/g to CH₄ at a pressure of 1.4 MPa. The most important study used to assess the possibilities of CO₂ storage and gas recovery from shale rocks were the CO₂/CH₄ exchange experiments, which were carried out under confining pressure conditions of 5 MPa and 30 MPa. These experiments were carried out on a unique apparatus, which makes it possible to apply a confining pressure corresponding to in situ conditions. The obtained results made it possible to carry out a comprehensive balance of gas exchange during the injection of CO₂ into the shale sample, with simultaneous recovery of CH₄. Based on the conducted sorption and gas exchange studies on the core sample under confining pressure conditions, it was found that in situ conditions, at the depths of shale gas occurrence in Poland of 3000-4000 m, where the confining pressure can be about 100 MPa: (i) poorly developed pore structure, (ii) very low permeability, and (iii) low sorption properties, make shale rocks poorly predisposed to the application of CO₂ storage technology with simultaneous recovery of CH₄. Without the stimulation of CO₂/CH₄ exchange rates through fracturing processes, the effectiveness of CO₂-ESGR technology on shale rock is very low. The research presented in this work is extremely important from the point of view of precise assessment of the potential of CO₂-ESGR technology.

Keywords: shale gas, shale rocks, CO₂/CH₄ exchange, permeability, sorption, CO₂, CH₄

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Authors: Yimei Huang, Harvey Lui, Jianhua Zhao, Zhenguo Wu, Haishan Zeng

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Conventional laser treatment of skin diseases and cosmetic surgery is based on the principle of one-photon absorption selective photothermolysis which relies strongly on the difference in the light absorption between the therapeutic target and its surrounding tissue. However, when the difference in one-photon absorption is not sufficient, collateral damage would occur due to indiscriminate and nonspecific tissue heating. To overcome this problem, we developed a spatially selective photothermolysis method based on multiphoton absorption in which the heat generation is restricted to the focal point of a tightly focused near-infrared femtosecond laser beam aligned with the target of interest. A multimodal optical microscope with co-registered reflectance confocal imaging (RCM), two-photon fluorescence imaging (TPF), and second harmonic generation imaging (SHG) capabilities was used to perform and monitor the spatially selective photothermolysis. Skin samples excised from the shaved backs of euthanized NODSCID mice were used in this study. Treatments were performed by focusing and scaning the laser beam in the dermis with a 50µm×50µm target area. Treatment power levels of 200 mW to 400 mW and modulated pulse trains of different duration and period were experimented. Different treatment parameters achieved different degrees of spatial confinement of tissue alterations as visualized by 3-D RCM/TPF/SHG imaging. At 200 mW power level, 0.1 s pulse train duration, 4.1 s pulse train period, the tissue damage was found to be restricted precisely to the 50µm×50µm×10µm volume, where the laser focus spot had scanned through. The overlying epidermis/dermis tissue and the underneath dermis tissue were intact although there was light passing through these regions.

Keywords: multiphoton absorption photothermolysis, reflectance confocal microscopy, second harmonic generation microscopy, spatially selective photothermolysis, two-photon fluorescence microscopy

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Authors: Xuechun Kan, Dongdong Li, Fan Li, Peidang Liu

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Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer with a poor prognosis, and radiotherapy is one of the main treatment methods. However, due to the obvious resistance of tumor cells to radiotherapy, high dose of ionizing radiation is required during radiotherapy, which causes serious damage to normal tissues near the tumor. Therefore, how to improve radiotherapy resistance and enhance the specific killing of tumor cells by radiation is a hot issue that needs to be solved in clinic. Recent studies have shown that silver-based nanoparticles have strong radiosensitization, and silver nanoclusters (AgNCs) also provide a broad prospect for tumor targeted radiosensitization therapy due to their ultra-small size, low toxicity or non-toxicity, self-fluorescence and strong photostability. Aptamer 5TR1 is a 25-base oligonucleotide aptamer that can specifically bind to mucin-1 highly expressed on the membrane surface of TNBC 4T1 cells, and can be used as a highly efficient tumor targeting molecule. In this study, AgNCs were synthesized by DNA template based on 5TR1 aptamer (NC-T5-5TR1), and its role as a targeted radiosensitizer in TNBC radiotherapy was investigated. The optimal DNA template was first screened by fluorescence emission spectroscopy, and NC-T5-5TR1 was prepared. NC-T5-5TR1 was characterized by transmission electron microscopy, ultraviolet-visible spectroscopy and dynamic light scattering. The inhibitory effect of NC-T5-5TR1 on cell activity was evaluated using the MTT method. Laser confocal microscopy was employed to observe NC-T5-5TR1 targeting 4T1 cells and verify its self-fluorescence characteristics. The uptake of NC-T5-5TR1 by 4T1 cells was observed by dark-field imaging, and the uptake peak was evaluated by inductively coupled plasma mass spectrometry. The radiation sensitization effect of NC-T5-5TR1 was evaluated through cell cloning and in vivo anti-tumor experiments. Annexin V-FITC/PI double staining flow cytometry was utilized to detect the impact of nanomaterials combined with radiotherapy on apoptosis. The results demonstrated that the particle size of NC-T5-5TR1 is about 2 nm, and the UV-visible absorption spectrum detection verifies the successful construction of NC-T5-5TR1, and it shows good dispersion. NC-T5-5TR1 significantly inhibited the activity of 4T1 cells and effectively targeted and fluoresced within 4T1 cells. The uptake of NC-T5-5TR1 reached its peak at 3 h in the tumor area. Compared with AgNCs without aptamer modification, NC-T5-5TR1 exhibited superior radiation sensitization, and combined radiotherapy significantly inhibited the activity of 4T1 cells and tumor growth in 4T1-bearing mice. The apoptosis level of NC-T5-5TR1 combined with radiation was significantly increased. These findings provide important theoretical and experimental support for NC-T5-5TR1 as a radiation sensitizer for TNBC.

Keywords: 5TR1 aptamer, silver nanoclusters, radio sensitization, triple-negative breast cancer

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Authors: Ertuğ Yıldırım, Dile Kara, Salih Zeki Yıldız

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Metal containing polymers (MCPs) are macro molecules usually containing metal-ligand coordination units and are a multidisciplinary research field mainly based at the interface between coordination chemistry and polymer science. The progress of this area has also been reinforced by the growth of several other closely related disciplines including macro molecular engineering, crystal engineering, organic synthesis, supra molecular chemistry and colloidal and material science. Schiff base ligands are very effective in constructing supra molecular architectures such as coordination polymers, double helical and triple helical complexes. In addition, Schiff base derivatives incorporating a fluorescent moiety are appealing tools for optical sensing of metal ions. MCPs are well-known systems in which the combinations of local parameters are possible by means of fluoro metric techniques. Generally, without incorporation of the fluorescent groups with polymers is unspecific, and it is not useful to analyze their fluorescent properties. Therefore, it is necessary to prepare a new type epoxy polymers with fluorescent groups in terms of metal sensing prop and the other photo chemical applications. In the present study metal containing polymers were prepared via poly functional monomeric Schiff base metal chelate complexes in the presence of dis functional monomers such as diglycidyl ether Bisphenol A (DGEBA). The synthesized complexes and polymers were characterized by FTIR, UV-VIS and mass spectroscopies. The preparations of epoxy polymers have been carried out at 185 °C. The prepared composites having sharp and narrow excitation/emission properties are expected to be applicable in various systems such as heat-resistant polymers and photo voltaic devices. The prepared composite is also ideal for various applications, easily prepared, safe, and maintain good fluorescence properties.

Keywords: Schiff base ligands, crystal engineering, fluorescence properties, Metal Containing Polymers (MCPs)

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Authors: Stephanie Hernández-Carreón, Judith Virginia Ríos-Arana

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Microplastics (MPs) are plastic particles smaller than 5 mm that has been detected in soil, air, organisms, and mostly water around the world. Most studies have focused on MPs detection in marine waters, and less so in freshwater, such is the case of Mexico, where studies about MPs in freshwaters are limited. One of the most important rivers in the country is The Rio Grande/Río Bravo, a natural border between Mexico and the United States. Its waters serve different purposes, such as fishing, habitat to endemic species, electricity generation, agriculture, and drinking water sources, among others. Despite its importance, the river’s waters have not been analyzed to determine the presence of MPs; therefore, the purpose of this research is to determine if the Rio Bravo/Rio Grande is polluted with microplastics. For doing so, three sites (Borderland, Casa de Adobe, and Guadalupe) along the El Paso-Juárez metroplex have been sampled: 30 L of water were filtered through a plankton net (64 µm) in each site and sediments-composed samples were collected. Water samples and sediments were 1) digested with a hydrogen peroxide solution (30%), 2) resuspended in a calcium chloride solution (1.5 g/cm3) to separate MPs, and 3) filtered through a 0.45 µm nitrocellulose membrane. Processed water samples were dyed with Nile Red (1 mg/ml ethanol) and analyzed by fluorescence microscopy. Two water samples have been analyzed until January 2023: Casa de Adobe and Borderland finding a concentration of 5.67 particles/L and 5.93 particles/L, respectively. Three types of particles were observed: fibers, fragments, and films, fibers being the most abundant. These data, as well as the data obtained from the rest of the samples, will be analyzed by an ANOVA (α=0.05). The concentrations and types of particles found in the Río Bravo correspond with other studies on rivers associated with urban environments and agricultural activities in China, where a range of 3.67—10.7 particles/L was reported in the Wei River. Even though we are in the early stages of the study, and three new sites will be sampled and analyzed in 2023 to provide more data about this issue in the river, this presents the first evidence of microplastic pollution in the Rio Grande.

Keywords: microplastics, fresh water, Rio Bravo, fluorescence microscopy

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Authors: P. Comendador, I. Garcia, S. Orozco, L. Santamaria, M. Amutio, G. Lopez, M. Olazar

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In situ CO₂ capture in steam reforming processes has been studied in the last years as an alternative for increasing H₂ yields and H₂ purity in the product stream. For capturing the CO₂ at the reforming conditions, CaO-based sorbents are usually employed due to their properties at high temperature, low cost and high availability. However, the challenge is to develop high-capacity (gCO₂/gsorbent) materials that retain their capacity over cycles of operation. Besides, since the objective is to capture the CO₂ generated in situ, another key aspect is the sorption dynamics, which means that, in order to efficiently use the sorbent, it has to capture the CO₂ at a rate equal to or higher than the generation rate. In this work, different CaO-based materials have been prepared to aim at meeting these criteria. First, and by using the wet mixing method, different inert materials (Mg, Ce and Al) were combined with CaO. Second, and with the inert material selected (Mg), the effect of its concentration in the final material was studied. Transversally, the calcination temperature was also evaluated. It was determined that the wet mixing method is a simple procedure suitable for the preparation of CaO sorbents mixed with inert materials. The materials prepared by mixing the CaO with Mg have shown satisfactory anti-sintering properties and adequate sorption kinetics for their application in steam reforming processes. Regarding the concentration of Mg in the solid, it was concluded that high values contribute to the stability but at the expense of losing sorption capacity. Finally, it was observed that high calcination temperatures negatively affected the sorption properties of the final materials due to the decrease in the pore volume and the specific surface area.

Keywords: calcination temperature effect, CO₂ capture, Mg-Ce-Al stabilizers, Mg varying concentration effect, Sorbent stabilization

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Authors: P. V. S. Mascarenhas, B. C. P. Albuquerque, D. J. F. Campos, L. L. Almeida, V. R. Domingues, L. C. S. M. Ozelim

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Retaining slope structures are increasingly considered in geotechnical engineering projects due to extensive urban cities growth. These kinds of engineering constructions may present instabilities over the time and may require reinforcement or even rebuilding of the structure. In this context, statistical analysis is an important tool for decision making regarding retaining structures. This study approaches the failure probability of the construction of a retaining wall over the debris of an old and collapsed one. The new solution’s extension length will be of approximately 350 m and will be located over the margins of the Lake Paranoá, Brasilia, in the capital of Brazil. The building process must also account for the utilization of the ruins as a caisson. A series of in situ and laboratory experiments defined local soil strength parameters. A Standard Penetration Test (SPT) defined the in situ soil stratigraphy. Also, the parameters obtained were verified using soil data from a collection of masters and doctoral works from the University of Brasília, which is similar to the local soil. Initial studies show that the concrete wall is the proper solution for this case, taking into account the technical, economic and deterministic analysis. On the other hand, in order to better analyze the statistical significance of the factor-of-safety factors obtained, a Monte Carlo analysis was performed for the concrete wall and two more initial solutions. A comparison between the statistical and risk results generated for the different solutions indicated that a Gabion solution would better fit the financial and technical feasibility of the project.

Keywords: economical analysis, probability of failure, retaining walls, statistical analysis

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Authors: Joanna Cabaj, Sylwia Baluta, Karol Malecha, Kamila Drzozga

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Catecholamines are the principal neurotransmitters that mediate a variety of the central nervous system functions, such as motor control, cognition, emotion, memory processing, and endocrine modulation. Dysfunctions in catecholamine neurotransmission are induced in some neurologic and neuropsychiatric diseases. Changeable neurotransmitters level in biological fluids can be a marker of several neurological disorders. Because of its significance in analytical techniques and diagnostics, sensitive and selective detection of neurotransmitters is increasingly attracting a lot of attention in different areas of bio-analysis or biomedical research. Recently, fluorescent techniques for detection of catecholamines have attracted interests due to their reasonable cost, convenient control, as well as maneuverability in biological environments. Nevertheless, with the observed need for a sensitive and selective catecholamines sensor, the development of a convenient method for this neurotransmitter is still at its basic level. The manipulation of nanostructured materials in conjunction with biological molecules has led to the development of a new class of hybrid modified biosensors in which both enhancement of charge transport and biological activity preservation may be obtained. Immobilization of biomaterials on electrode surfaces is the crucial step in fabricating electrochemical as well as optical biosensors and bioelectronic devices. Continuing systematic investigation in the manufacturing of enzyme–conducting sensitive systems, here is presented a convenient fluorescence sensing strategy for catecholamines detection based on FRET (fluorescence resonance energy transfer) phenomena observed for, i.e., complexes of Fe²⁺ and epinephrine. The biosensor was constructed using low temperature co-fired ceramics technology (LTCC). This sensing system used the catalytical oxidation of catecholamines and quench of the strong luminescence of obtained complexes due to FRET. The detection process was based on the oxidation of substrate in the presence of the enzyme–laccase/tyrosinase.

Keywords: biosensor, conducting polymer, enzyme, FRET, LTCC

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Authors: Chia-Chia Chang, Jhen-Ting Huang, Hu-Cheng Weng, An-Ya Lo

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This study developed a simple hierarchical porous carbon (HPC) synthesis process and used for supercapacitor application. In which, mesopore provides huge specific surface area, meanwhile, macropore provides excellent mass transfer. Thus the hierarchical porous electrode improves the charge-discharge performance. On the other hand, cerium oxide (CeO2) have also got a lot research attention owing to its rich in content, low in price, environmentally friendly, good catalytic properties, and easy preparation. Besides, a rapid redox reaction occurs between trivalent cerium and tetravalent cerium releases oxygen atom and increase the conductivity. In order to prevent CeO2 from disintegration under long-term charge-discharge operation, the CeO2 carbon porous materials were was integrated as composite material in this study. For in the ex-situ analysis, scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscope (TEM) analysis were adopted to identify the surface morphology, crystal structure, and microstructure of the composite. 77K Nitrogen adsorption-desorption analysis was used to analyze the porosity of each specimen. For the in-situ test, cyclic voltammetry (CV) and chronopotentiometry (CP) were conducted by potentiostat to understand the charge and discharge properties. Ragone plot was drawn to further analyze the resistance properties. Based on above analyses, the effect of macropores/mespores and the CeO2/HPC ratios on charge-discharge performance were investigated. As a result, the capacitance can be greatly enhanced by 2.6 times higher than pristine mesoporous carbon electrode.

Keywords: hierarchical porous carbon, cerium oxide, supercapacitor

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Authors: Tarek Aboueldahab, Hanan Farag

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Cost minimization of Multiple Vehicle Routing Problem becomes a critical issue in the field of transportation because it is NP-hard optimization problem and the search space is complex. Many researches use the hybridization of artificial intelligence (AI) models to solve this problem; however, it can not guarantee to reach the best solution due to the difficulty of searching the whole search space. To overcome this problem, we introduce the hybrid model of Discrete Particle Swarm Optimization (DPSO) with a passive congregation which enable searching the whole search space to compromise between both local and global search. The practical experiment shows that our model obviously outperforms other hybrid models in cost minimization.

Keywords: cost minimization, multi-vehicle routing problem, passive congregation, discrete swarm, passive congregation

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Authors: Ipek Gunay, Efe B. Orman, Metin Ozer, Bekir Salih, Ali R. Ozkaya

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Phthalocyanines with macrocyclic ring containing at least three heteroatoms have nine or more membered structures. Metal-free phthalocyanines react with metal salts to obtain chelate complexes. This is one of the most important features of metal-free phthalocyanine as ligand structure. Although phthalocyanines have very similar properties with porphyrins, they have some advantages such as lower cost, easy to prepare, and chemical and thermal stability. It’s known that Pc compounds have shown one-electron metal-and/or ligand-based reversible or quasi-reversible reduction and oxidation processes. The redox properties of phthalocyanines are critically related to the desirable properties of these compounds in their technological applications. Thus, Pc complexes have also been receiving increasing interest in the area of fuel cells due to their high electrocatalytic activity in dioxygen reduction and fuel cell applications. In this study, novel phthalocyanine complexes coordinated with Fe(II) and Co (II) to be used as catalyst were synthesized. Aiming this goal, a new nitrile ligand was synthesized starting from 4-hydroxy-3,5-dimethoxy benzyl alcohol and 4-nitrophthalonitrile in the presence of K2CO3 as catalyst. After the isolation of the new type of nitrile and metal complexes, the characterization of mentioned compounds was achieved by IR, H-NMR and UV-vis methods. In addition, the electrochemical behaviour of Pc complexes was identified by cyclic voltammetry, square wave voltammetry and in situ spectroelectrochemical measurements. Furthermore, the catalytic performances of Pc complexes for oxygen reduction were tested by dynamic voltammetry measurements, carried out by the combined system of rotating ring-disk electrode and potentiostat, in a medium similar to fuel-cell working conditions.

Keywords: phthalocyanine, electrocatalysis, electrochemistry, in-situ spectroelectrochemistry

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Authors: Marcela Karmazínová, Jindrich Melcher, Lubomír Vítek, Petr Cikrle

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The paper deals with the diagnostics of steel roof structure of the winter sports stadiums built in 1970 year. The necessity of the diagnostics has been given by the requirement to the evaluation design of this structure, which has been caused by the new situation in the field of the loadings given by the validity of the European Standards in the Czech Republic from 2010 year. Due to these changes in the normative rules, in practice, existing structures are gradually subjected to the evaluation design and depending on its results to the strengthening or reconstruction, respectively. The steel roof is composed of plane truss main girders, purlins and bracings and the roof structure is supported by two arch main girders with the span of L=84 m. The in situ diagnostics of the roof structure was oriented to the following parts: (i) determination and evaluation of the actual material properties of used steel and (ii) verification of the actual dimensions of the structural members. For the solution, the non-destructive methods have been used for in situ measurement. For the indicative determination of steel strengths the modified method based on the determination of Rockwell’s hardness has been used. For the verification of the member’s dimensions (thickness of hollow sections) the ultrasound method has been used. This paper presents the results obtained using these testing methods and their evaluation, from the viewpoint of the usage for the subsequent static assessment and design evaluation of the existing structure. For the comparison, the examples of the similar evaluations realized for steel structures of the stadiums in Olomouc and Jihlava cities are briefly illustrated, too.

Keywords: actual dimensions, destructive methods, diagnostics, existing steel structure, indirect non-destructive methods, Rockwel’s hardness, sport hall, steel strength, ultrasound method.

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Authors: Tibor Ajtai, Noémi Utry, Máté Pintér, Gábor Szabó, Zoltán Bozóki

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Beyond its climate and health related issues ambient light absorbing carbonaceous particulate matter (LAC) has also become a great scientific interest in terms of its regulations recently. It has been experimentally demonstrated in recent studies, that LAC is dominantly composed of traffic and wood burning aerosol particularly under wintertime urban conditions, when the photochemical and biological activities are negligible. Several methods have been introduced to quantitatively apportion aerosol fractions emitted by wood burning and traffic but most of them require costly and time consuming off-line chemical analysis. As opposed to chemical features, the microphysical properties of airborne particles such as optical absorption and size distribution can be easily measured on-line, with high accuracy and sensitivity, especially under highly polluted urban conditions. Recently a new method has been proposed for the apportionment of wood burning and traffic aerosols based on the spectral dependence of their absorption quantified by the Aerosol Angström Exponent (AAE). In this approach the absorption coefficient is deduced from transmission measurement on a filter accumulated aerosol sample and the conversion factor between the measured optical absorption and the corresponding mass concentration (the specific absorption cross section) are determined by on-site chemical analysis. The recently developed multi-wavelength photoacoustic instruments provide novel, in-situ approach towards the reliable and quantitative characterization of carbonaceous particulate matter. Therefore, it also opens up novel possibilities on the source apportionment through the measurement of light absorption. In this study, we demonstrate an in-situ spectral characterization method of the ambient carbon fraction based on light absorption and size distribution measurements using our state-of-the-art multi-wavelength photoacoustic instrument (4λ-PAS) and Single Mobility Particle Sizer (SMPS) The carbonaceous particulate selective source apportionment study was performed for ambient particulate matter in the city center of Szeged, Hungary where the dominance of traffic and wood burning aerosol has been experimentally demonstrated earlier. The proposed model is based on the parallel, in-situ measurement of optical absorption and size distribution. AAEff and AAEwb were deduced from the measured data using the defined correlation between the AOC(1064nm)/AOC(266nm) and N100/N20 ratios. σff(λ) and σwb(λ) were determined with the help of the independently measured temporal mass concentrations in the PM1 mode. Furthermore, the proposed optical source apportionment is based on the assumption that the light absorbing fraction of PM is exclusively related to traffic and wood burning. This assumption is indirectly confirmed here by the fact that the measured size distribution is composed of two unimodal size distributions identified to correspond to traffic and wood burning aerosols. The method offers the possibility of replacing laborious chemical analysis with simple in-situ measurement of aerosol size distribution data. The results by the proposed novel optical absorption based source apportionment method prove its applicability whenever measurements are performed at an urban site where traffic and wood burning are the dominant carbonaceous sources of emission.

Keywords: absorption, size distribution, source apportionment, wood burning, traffic aerosol

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Authors: Guanghua Lu, Zhenhua Yan

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To investigate the estrogenic contamination and potential risk of Taihu Lake, eight active biomonitoring points in the northern section of Taihu Lake were set up and located in Wangyuhe River outlet (P1), Gonghu Bay (P2 and P3), Meiliang Bay (P4 and P5), Zhushan Bay (P6 and P7) and Lake Centre (P8). A suite of biomarkers in caged fish after in situ exposure for 28 days, coupled with six selected exogenous estrogens in water, were determined in May and December 2011. Six target estrogens, namely estrone (E1), 17b-estradiol (E2), ethinylestradiol (EE2), estriol (E3), diethylstilbestrol (DES) and bisphenol A (BPA), were quantified using UPLC/MS/MS. The concentrations of E1, E2, E3, EE2, DES and BPA ranged from ND to 3.61 ng/L, ND to 17.3 ng/L, ND to 1.65 ng/L, ND to 10.2 ng/L, ND to 34.6 ng/L, and 3.95 to 207 ng/L, respectively. BPA was detected at all sampling points at all test periods, E2 was detected at 95% of samples, E1 and EE2 was detected at 75% of samples, and E3 was detected only in December 2011 with quite low concentrations. Each individual estrogen concentration measured at each sampling point was multiplied by its relative potency to gain the estradiol equivalent (EEQ). The total EEQ values in all the monitoring points ranged from 5.69 to 17.8 ng/L in May 2011, and from 4.46 to 21.1 ng/L in December 2011. E2 and EE2 were thought to be the major causal agents responsible for the estrogenic activities. Serum vitellogenin and E2 levels, gonadal DNA damage, and gonadosomatic index were measured in the in situ exposed fish. An enhanced integrated biomarker response (EIBR) was calculated and used to evaluate potential feminization risk of fish in the polluted area of Taihu Lake. EIBR index showed good agreement with the observed total EEQ levels in water. Our results indicated that Gong bay and the lake center had a low estrogenic risk, whereas Wangyuhe River, Meiliang Bay, and Zhushan Bay might present a higher risk to fish.

Keywords: active biomonitoring, estrogen, feminization risk, Taihu Lake

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Authors: Chia-Ting Chang, Chia-Yu Lin

Abstract:

We report on the decisive role of iron phosphate (FePO₄), formed in-situ during the electrochemical characterization, played in the electrocatalytic activity, especially its oxygen tolerance of iron oxides towards H₂O₂ reduction. Iron oxides studied including, Nanorod arrays (NRs) of β-FeOOH, γ-Fe₂O₃, α-Fe₂O₃, α-Fe₂O₃ nanosheets (α-Fe₂O₃NS), α-Fe₂O₃ nanoparticles (α-Fe₂O₃NP), were synthesized using chemical bath deposition. The nanostructure was controlled simply by adjusting the composition of precursor solution and reaction duration for CBD process, whereas the crystal phase was controlled by adjusting the annealing temperature. It was found that iron phosphate (FePO₄) was deposited in-situ onto the surface of this nanostructured α-Fe₂O₃ during the electrochemical pretreatment in the phosphate electrolyte, and both FePO₄ and α-Fe₂O₃ showed the activity in catalysing the electrochemical reduction of H₂O₂. In addition, the interaction/compatibility between deposited FePO₄ and iron oxides has a decisive effect on the overall electrocatalytic activity of the resultant electrodes; FePO₄ only showed synergetic effect on the overall electrocatalytic activity of α-Fe₂O₃NR and α-Fe2O₃NS. Both α-Fe₂O₃NR and α-Fe₂O₃NS showed two reduction peaks in phosphate electrolyte containing H₂O₂, one being pH-dependent and related to the electrocatalytic properties of FePO₄, and the other one being pH-independent and only related to the intrinsic electrocatalytic properties of α-Fe₂O₃NR and α-Fe₂O₃NS. However, all iron oxides showed only one pH-independent reductive peak in non-phosphate electrolyte containing H₂O₂. The synergesitic catalysis exerted by FePO₄ with α-Fe₂O₃NR or α-Fe₂O₃NS providing additional oxygen-insensitive active site for H₂O₂ reduction, which allows their applications to electrochemical detection of H₂O₂ without the interference of O₂ involving in oxidase-catalyzed chemical processes.

Keywords: H₂O₂ reduction, Iron oxide, iron phosphate, O₂ tolerance

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Authors: Daniela Rimnacova, Maryna Vorokhta, Martina Svabova

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CO₂ adsorption capacity of several materials - waste (power fly ash, slag, carbonized sewage sludge), rocks (Czech Silurian shale, black coal), and carbon (synthesized carbon, activated carbon as a reference material) - were measured on dry samples using a unique hand-made manometric sorption apparatus at a temperature of 45 °C and pressures of up to 7 MPa. The main aim was finding utilization of the waste materials and rocks for removal of the air or water pollutants caused by anthropogenic activities, as well as for the carbon dioxide storage. The equilibrium amount of the adsorbate depends on temperature, gas saturation pressure, porosity, surface area and volume of pores, and last but not least, on the composition of the adsorbents. Given experimental conditions can simulate in-situ situations in the rock bed and can be achieved just by a high-pressure apparatus. The CO₂ excess adsorption capacities ranged from 0.018 mmol/g (ash) to 13.55 mmol/g (synthesized carbon). The synthetized carbon had the highest adsorption capacity among all studied materials as well as the highest price. This material is usually used for the adsorption of specific pollutants. The excess adsorption capacity of activated carbon was 9.19 mmol/g. It is used for water and air cleaning. Ash can be used for chemisorption onto ash particle surfaces or capture of special pollutants. Shale is a potential material for enhanced gas recovery or CO₂ sequestration in-situ. Slag is a potential material for capture of gases with a possibility of the underground gas storage after the adsorption process. The carbonized sewage sludge is quite a good adsorbent for the removal and capture of pollutants, as well as shales or black coal which show an interesting relationship between the price and adsorption capacity.

Keywords: adsorption, CO₂, high pressure, porous materials

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Authors: Natacha Fery, Guilherme L. Dalledonne, Xiangyang Zheng, Cheng Tang, Roberto Mayerle

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A Decision Support System (DSS) for supporting decision makers in the management of the Shandong Peninsula has been developed. Emphasis has been given to coastal protection, coastal cage aquaculture and harbors. The investigations were done in the framework of a joint research project funded by the German Ministry of Education and Research (BMBF) and the Chinese Academy of Sciences (CAS). In this paper, a description of the DSS, the development of its components, and results of its application are presented. The system integrates in-situ measurements, process-based models, and a database management system. Numerical models for the simulation of flow, waves, sediment transport and morphodynamics covering the entire Bohai Sea are set up based on the Delft3D modelling suite (Deltares). Calibration and validation of the models were realized based on the measurements of moored Acoustic Doppler Current Profilers (ADCP) and High Frequency (HF) radars. In order to enable cost-effective and scalable applications, a database management system was developed. It enhances information processing, data evaluation, and supports the generation of data products. Results of the application of the DSS to the management of coastal protection, coastal cage aquaculture and harbors are presented here. Model simulations covering the most severe storms observed during the last decades were carried out leading to an improved understanding of hydrodynamics and morphodynamics. Results helped in the identification of coastal stretches subjected to higher levels of energy and improved support for coastal protection measures.

Keywords: coastal protection, decision support system, in-situ measurements, numerical modelling

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Authors: Saeedeh Hajihosseini, Zahra Aghili, Navid Nasirizadeh

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An innovative method of a DNA electrochemical biosensor based on Oracet Blue (OB) as an electroactive label and gold electrode (AuE) for detection of Helicobacter pylori, was offered. A single–stranded DNA probe with a thiol modification was covalently immobilized on the surface of the AuE by forming an Au–S bond. Differential pulse voltammetry (DPV) was used to monitor DNA hybridization by measuring the electrochemical signals of reduction of the OB binding to double– stranded DNA (ds–DNA). Our results showed that OB–based DNA biosensor has a decent potential for detection of single–base mismatch in target DNA. Selectivity of the proposed DNA biosensor was further confirmed in the presence of non–complementary and complementary DNA strands. Under optimum conditions, the electrochemical signal had a linear relationship with the concentration of the target DNA ranging from 0.3 nmol L-1 to 240.0 nmol L-1, and the detection limit was 0.17 nmol L-1, whit a promising reproducibility and repeatability.

Keywords: DNA biosensor, oracet blue, Helicobacter pylori, electrode (AuE)

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Authors: Reem Alajmi, Hind Al Harbi, Tahany Ayaad, Zainab Al Musawi

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Hard ticks Hyalomma spp. (family: Ixodidae) are obligate ectoparasite in their all life stages on some domestic animals mainly camels and cattle. Ticks may lead to many economic and public health problems because of their blood feeding behavior. Also, they act as vectors for many bacterial, viral and protozoan agents which may cause serious diseases such as tick-born encephalitis, Rocky-mountain spotted fever, Q-fever and Lyme disease which can affect human and/or animals. In the present study, molecular identification of ticks that attack camels in Riyadh region, Saudi Arabia based on the partial sequence of mitochondrial 16s rRNA gene was applied. Also, the present study aims to detect natural infections of collected camel ticks with Rickessia spp. and Borelia spp. using PCR/hybridization of Citrate synthase encoding gene present in bacterial cells. Hard ticks infesting camels were collected from different camels located in a farm in Riyadh region, Saudi Arabia. Results of the present study showed that the collected specimens belong to two species: Hyalomma dromedari represent 99% of the identified specimens and Hyalomma marginatum which account for 1 % of identified ticks. The molecular identification was made through blasting the obtained sequence of this study with sequences already present and identified in GeneBank. All obtained sequences of H. dromedarii specimens showed 97-100% identity with the same gene sequence of the same species (Accession # L34306.1) which was used as a reference. Meanwhile, no intraspecific variations of H. marginatum mesured because only one specimen was collected. Results also had shown that the intraspecific variability between individuals of H. dromedarii obtained in 92 % of samples ranging from 0.2- 6.6%, while the remaining 7 % of the total samples of H. dromedarii showed about 10.3 % individual differences. However, the interspecific variability between H. dromedarii and H. marginatum was approximately 18.3 %. On the other hand, by using the technique of PCR/hybridization, we could detect natural infection of camel ticks with Rickettsia spp. and Borrelia spp. Results revealed the natural presence of both bacteria in collected ticks. Rickettsial spp. infection present in 29% of collected ticks, while 35% of collected specimen were infected with Borrelia spp. The valuable results obtained from the present study are a new record for the molecular identification of camel ticks in Riyadh, Saudi Arabia and their natural infection with both Rickettsia spp. and Borrelia spp. These results may help scientists to provide a good and direct control strategy of ticks in order to protect one of the most important economic animals which are camels. Also results of this project spotlight on the disease that might be transmitted by ticks to put out a direct protective plan to prevent spreading of these dangerous agents. Further molecular studies are needed to confirm the results of the present study by using other mitochondrial and nuclear genes for tick identification.

Keywords: Camel ticks, Rickessia spp. , Borelia spp. , mitochondrial 16s rRNA gene

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Authors: Ghazi Faisal Najmuldeen, Wahida Amat Fadzila

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The aim of this study is to investigate physical and mechanical properties of experimental particleboards manufactured from mixing the oil palm fronds particles with empty fruit bunch fibers. Variables were two blending ratios (100:0 and 70:30), press temperature (160°C and 180°C) and press time (180 and 300 s). Experimental boards with a target density of 750 kg m-3 were manufactured from these two particles and fibers blended with urea formaldehyde resin and compressed into targeted thickness. The effect of these manufacturing conditions on bending strength, internal bonding, water absorption and thickness swelling were determined. From this research, it can be concluded that hybridization of fibers with fronds particles improved some properties of particleboard. Empty fruit bunch fibers and fronds particleboard showed better modulus of rupture and internal bonding than fronds particleboards.

Keywords: oil palm fronds, empty fruit bunch, particleboards, chemistry, environment

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Authors: Parvin Berenjkar, Qiuyan Yuan, Richard Sparling, Stan Lozecznik

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Landfills highly contribute to anthropological global warming through CH₄ emissions. Landfills are usually capped by a conventional soil cover to control the migration of gases. Methane is consumed by CH₄-oxidizing microorganisms known as methanotrophs that naturally exist in the landfill soil cover. The growth of methanotrophs can be optimized in a bio-cover that typically consists of a gas distribution layer (GDL) to homogenize landfill gas fluxes and an overlying oxidation layer composed of suitable materials that support methanotrophic populations. Materials such as mature yard waste composts can provide an inexpensive and favourable porous support for the growth and activity of methanotrophs. In areas with seasonal cold climates, it is valuable to know if methanotrophs in a bio-cover can survive in winter until the next spring, and how deep they are active in the bio-cover to mitigate CH₄. In this study, a pilot bio-cover was constructed in a closed landfill cell in Winnipeg that has a very cold climate in Canada. The bio-cover has a surface area of 2.5 m x 3.5 m and 1.5 m of depth, filled with 50 cm of gravel as a GDL and 70 cm of biosolids compost amended with yard and leaf waste compost. The observed in situ potential of methanotrophs for CH₄ oxidation was investigated at a specific period of time from December 2016 to April 2017 as well as November 2017 to April 2018, when the transition to surface frost and thawing happens in the bio-cover. Compost samples taken from different depths of the bio-cover were incubated in the laboratory under standardized conditions; an optimal air: methane atmosphere, at 22ºC, but at in situ moisture content. Results showed that the methanotrophs were alive oxidizing methane without a lag, indicating that there was the potential for methanotrophic activity at some depths of the bio-cover.

Keywords: bio-cover, global warming, landfill, methanotrophic activity

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Authors: Kalyani Mer

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Hydrogen peroxide (H₂O₂) is one of the most efficient and commonly used oxidants in in-situ chemical oxidation (ISCO) of organic contaminants. In the present study, we investigated the activation of H₂O₂ by heavy metal (nickel and lead metal ions) loaded biochar for phenol degradation in an aqueous solution (concentration = 100 mg/L). It was found that H₂O₂ can be effectively activated by biochar, which produces hydroxyl (•OH) radicals owing to an increase in the formation of persistent free radicals (PFRs) on biochar surface. Ultrasound treated (30s duration) biochar, chemically activated by 30% phosphoric acid and functionalized by diethanolamine (DEA) was used for the adsorption of heavy metal ions from aqueous solutions. It was found that modified biochar could remove almost 60% of nickel in eight hours; however, for lead, the removal efficiency reached up to 95% for the same time duration. The heavy metal loaded biochar was further used for the degradation of phenol in the absence and presence of H₂O₂ (20 mM), within 4 hours of reaction time. The removal efficiency values for phenol in the presence of H₂O₂ were 80.3% and 61.9%, respectively, by modified biochar loaded with nickel and lead metal ions. These results suggested that the biochar loaded with nickel exhibits a better removal capacity towards phenol than the lead loaded biochar when used in H₂O₂ based oxidation systems. Meanwhile, control experiments were set in the absence of any activating biochar, and the removal efficiency was found to be 19.1% when only H₂O₂ was added in the reaction solution. Overall, the proposed approach serves a dual purpose of using biochar for heavy metal ion removal and treatment of organic contaminants by further using the metal loaded biochar for H₂O₂ activation in ISCO processes.

Keywords: biochar, ultrasound, heavy metals, in-situ chemical oxidation, chemical activation

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Authors: Harpal Singh, Sakshi Batra

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The widespread and easy accesses to multimedia contents and possibility to make numerous copies without loss of significant fidelity have roused the requirement of digital rights management. Thus this problem can be effectively solved by Digital watermarking technology. This is a concept of embedding some sort of data or special pattern (watermark) in the multimedia content; this information will later prove ownership in case of a dispute, trace the marked document’s dissemination, identify a misappropriating person or simply inform user about the rights-holder. The primary motive of digital watermarking is to embed the data imperceptibly and robustly in the host information. Extensive counts of watermarking techniques have been developed to embed copyright marks or data in digital images, video, audio and other multimedia objects. With the development of digital video-based innovations, copyright dilemma for the multimedia industry increases. Video watermarking had been proposed in recent years to serve the issue of illicit copying and allocation of videos. It is the process of embedding copyright information in video bit streams. Practically video watermarking schemes have to address some serious challenges as compared to image watermarking schemes like real-time requirements in the video broadcasting, large volume of inherently redundant data between frames, the unbalance between the motion and motionless regions etc. and they are particularly vulnerable to attacks, for example, frame swapping, statistical analysis, rotation, noise, median and crop attacks. In this paper, an effective, robust and imperceptible video watermarking algorithm is proposed based on hybridization of powerful mathematical transforms; Fractional Fourier Transform (FrFT), Discrete Wavelet transforms (DWT) and Singular Value Decomposition (SVD) using redundant wavelet. This scheme utilizes various transforms for embedding watermarks on different layers by using Hybrid systems. For this purpose, the video frames are portioned into layers (RGB) and the watermark is being embedded in two forms in the video frames using SVD portioning of the watermark, and DWT sub-band decomposition of host video, to facilitate copyright safeguard as well as reliability. The FrFT orders are used as the encryption key that allows the watermarking method to be more robust against various attacks. The fidelity of the scheme is enhanced by introducing key generation and wavelet based key embedding watermarking scheme. Thus, for watermark embedding and extraction, same key is required. Therefore the key must be shared between the owner and the verifier via some safe network. This paper demonstrates the performance by considering different qualitative metrics namely Peak Signal to Noise ratio, Structure similarity index and correlation values and also apply some attacks to prove the robustness. The Experimental results are presented to demonstrate that the proposed scheme can withstand a variety of video processing attacks as well as imperceptibility.

Keywords: discrete wavelet transform, robustness, video watermarking, watermark

Procedia PDF Downloads 224

Authors: Edmaritz Hernandez-Pagan, Kanjana Laosuntisuk, Alex Harris, Allison Haynes, David Buitrago, Michael Kudenov, Colleen Doherty

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Rare Earth Elements (REEs) are critical metals for modern electronics, green technologies, and defense systems. However, due to their dispersed nature in the Earth’s crust, frequent co-occurrence with radioactive materials, and similar chemical properties, acquiring and purifying REEs is costly and environmentally damaging, restricting access to these metals. Plants could serve as resources for bioengineering REE mining systems. Although there is limited information on how REEs affect plants at a cellular and molecular level, plants with high REE tolerance and hyperaccumulation have been identified. This dissertation aims to develop a plant-based system for harvesting REEs from industrial waste material with a focus on Acid Mine Drainage (AMD), a toxic coal mining product. The objectives are 1) to develop a non-destructive, in vivo detection method for REE detection in Phytolacca plants (REE hyperaccumulator) plants utilizing fluorescence spectroscopy and with a primary focus on dysprosium, 2) to characterize the uptake of REE and Heavy Metals in Phytolacca americana and Phytolacca acinosa (REE hyperaccumulator) in AMD for potential implementation in the plant-based system, 3) to implement the REE detection method to identify REE-binding proteins and peptides for potential enhancement of uptake and selectivity for targeted REEs in the plants implemented in the plant-based system. The candidates are known REE-binding peptides or proteins, orthologs of known metal-binding proteins from REE hyperaccumulator plants, and novel proteins and peptides identified by comparative plant transcriptomics. Lanmodulin, a high-affinity REE-binding protein from methylotrophic bacteria, is used as a benchmark for the REE-protein binding fluorescence assays and expression in A. thaliana to test for changes in REE plant tolerance and uptake.

Keywords: phytomining, agromining, rare earth elements, pokeweed, phytolacca

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Authors: Disha Gupta

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The aim of this research is to conduct X-ray and e-beam characterization techniques on lithium-ion battery materials for the improvement of battery performance. The key characterization techniques employed are the synchrotron X-ray Absorption Spectroscopy (XAS) combined with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to obtain a more holistic approach to understanding material properties. This research effort provides additional battery characterization knowledge that promotes the development of new cathodes, anodes, electrolyte and separator materials for batteries, hence, leading to better and more efficient battery performance. Both ex-situ and in-situ synchrotron experiments were performed on LiFePO₄, one of the most common cathode material, from different commercial sources and their structural analysis, were conducted using Athena/Artemis software. This analysis technique was then further extended to study other cathode materials like LiMnxFe(₁₋ₓ)PO₄ and even some sulphate systems like Li₂Mn(SO₄)₂ and Li₂Co0.5Mn₀.₅ (SO₄)₂. XAS data were collected for Fe and P K-edge for LiFePO4, and Fe, Mn and P-K-edge for LiMnxFe(₁₋ₓ)PO₄ to conduct an exhaustive study of the structure. For the sulphate system, Li₂Mn(SO₄)₂, XAS data was collected at both Mn and S K-edge. Finite Difference Method for Near Edge Structure (FDMNES) simulations were also conducted for various iron, manganese and phosphate model compounds and compared with the experimental XANES data to understand mainly the pre-edge structural information of the absorbing atoms. The Fe K-edge XAS results showed a charge compensation occurring on the Fe atom for all the differently synthesized LiFePO₄ materials as well as the LiMnxFe(₁₋ₓ)PO₄ systems. However, the Mn K-edge showed a difference in results as the Mn concentration changed in the materials. For the sulphate-based system Li₂Mn(SO₄)₂, however, no change in the Mn K-edge was observed, even though electrochemical studies showed Mn redox reactions.

Keywords: li-ion batteries, electrochemistry, X-ray absorption spectroscopy, XRD

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Authors: Illahi Bakhsh Marghazani, Nasrullah, Masood Ul Haq Kakar, Abdul Hameed Baloch, Ahmad Nawaz Khoso, Behram Chacher

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Protein sources are the major part of ration fed to dairy buffaloes in Pakistan however, the limited availability and lack of judicious use of protein resources are further aggravating the conditions to enhance milk and meat production. In order to gain maximum production from limited protein source availability, it is necessary to balance feed for rumen degradable and rumen undegradable protein fractions. This study planned to know the rumen degradable and rumen undegradable fractions in all vegetable protein sources with (formaldehyde and heat treatment) and without treatments. Samples of soybean meal, corn gluten meal 60%, maize gluten feed, guar meal, sunflower meal, rapeseed meal, rapeseed cake, canola meal, cottonseed cake, cottonseed meal, coconut cake, coconut meal, palm kernel cake, almond cake and sesame cake were collected from ten different geographical locations of Pakistan. These samples were also subjected to formaldehyde (1% /100g CP of test feed) and heat treatments (1 hr at 15 lb psi/100 g CP of test feed). In situ technique was used to know the ruminal degradability characteristics. Data obtained were fitted to Orskove equation. Results showed that both treatments significantly (P < 0.05) decreased ruminal degradability in all vegetable protein sources than untreated vegetable protein sources, however, of both treatments, heat treatment was more effective than formaldehyde treatment in decreasing ruminal degradability in most of the studied vegetable protein sources.

Keywords: formaldehyde and heat treatments, in situ technique, rumen degradable and rumen undegradable fractions, vegetable protein sources

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Authors: Md. Samsuddin Ansari, Ashish Arora

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Every year 10 million people fall ill with one of the oldest diseases known as tuberculosis, caused by Mycobacterium tuberculosis. The success of M. tuberculosis as a pathogen is because of its ability to persist in host tissues. Multidrug resistance (MDR) mycobacteria cases increase every day, which is associated with efflux pumps controlled at the level of transcription. The transcription regulators of MDR transporters in bacteria belong to one of the following four regulatory protein families: AraC, MarR, MerR, and TetR. Phenolic acid decarboxylase repressor (PadR), like a family of transcription regulators, is closely related to the MarR family. Phenolic acid decarboxylase repressor (PadR) was first identified as a transcription factor involved in the regulation of phenolic acid stress response in various microorganisms (including Mycobacterium tuberculosis H37Rv). Recently research has shown that the PadR family transcription factors are global, multifunction transcription regulators. Rv0047c is a PadR subfamily-1 protein. We are exploring the biophysical and structural characterization of Rv0047c. The Rv0047 gene was amplified by PCR using the primers containing EcoRI and HindIII restriction enzyme sites cloned in pET-NH6 vector and overexpressed in DH5α and BL21 (λDE3) cells of E. coli following purification with Ni2+-NTA column and size exclusion chromatography. We did DSC to know the thermal stability; the Tm (transition temperature) of protein is 55.29ºC, and ΔH (enthalpy change) of 6.92 kcal/mol. Circular dichroism to know the secondary structure and conformation and fluorescence spectroscopy for tertiary structure study of protein. To understand the effect of pH on the structure, function, and stability of Rv0047c we employed spectroscopy techniques such as circular dichroism, fluorescence, and absorbance measurements in a wide range of pH (from pH-2.0 to pH-12). At low and high pH, it shows drastic changes in the secondary and tertiary structure of the protein. EMSA studies showed the specific binding of Rv0047c with its own 30-bp promoter region. To determine the effect of complex formation on the secondary structure of Rv0047c, we examined the CD spectra of the complex of Rv0047c with promoter DNA of rv0047. The functional role of Rv0047c was characterized by over-expressing the Rv0047c gene under the control of hsp60 promoter in Mycobacterium tuberculosis H37Rv. We have predicted the three-dimensional structure of Rv0047c using the Swiss Model and Modeller, with validity checked by the Ramachandra plot. We did molecular docking of Rv0047c with dnaA, through PatchDock following refinement through FireDock. Through this, it is possible to easily identify the binding hot-stop of the receptor molecule with that of the ligand, the nature of the interface itself, and the conformational change undergone by the protein pattern. We are using X-crystallography to unravel the structure of Rv0047c. Overall the studies show that Rv0047c may have transcription regulation along with providing an insight into the activity of Rv0047c in the pH range of subcellular environment and helps to understand the protein-protein interaction, a novel target to kill dormant bacteria and potential strategy for tuberculosis control.

Keywords: mycobacterium tuberculosis, phenolic acid decarboxylase repressor, Rv0047c, Circular dichroism, fluorescence spectroscopy, docking, protein-protein interaction

Procedia PDF Downloads 121

Authors: Li Li, Lei Wang, Chenglin Du, Mengxin Ren, Xinzheng Zhang, Wei Cai, Jingjun Xu

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Strong coupling between excitons of quantum dots and plasmons in nanocavites can be realized at room temperature due to the strong confinement of the plasmon fields, which offers building blocks for quantum information systems or ultralow-power switches and lasers. In this work, by using cathodoluminescence, ultrastrong coupling with Rabi splitting above 1 eV between breathing plasmons in Aluminum metal-insulator-metal (MIM) cavity and excited state of CdZnS/ZnS quantum dots was reported in near-UV spectrum. Analytic analysis and full-wave electromagnetic simulations provide the evidence for the strong coupling and confirm the hybridization of the QDs exciton and LSP breathing mode. This study opens the way for new emerging applications based on strongly coupled light-matter states all over the visible region down to ultra-violet frequencies.

Keywords: breathing mode, plasmonics, quantum dot, strong coupling, ultraviolet

Procedia PDF Downloads 199