Miracle-dz/UniFAR-FTUs huggingface dataset:
Towards quantum dot and FRET-based optical DNA biosensor technology: surface chemistry and photoluminescence of CdSe/ZnS and Si quantum dots

Quantum dots (QDs) are nanostructures that are highly attractive to optical biosensing. We have developed a nucleic acid biosensing strategy based on the use of quantum dots as energy donors in FRET. One of the challenges in such an approach is avoiding the non-specific adsorption of oligonucleotides. In this report, we describe our efforts to develop poly(ethylene glycol) (PEG)-based hydrophilic surface chemistry and hexanethiol based hydrophobic surface chemistry to alleviate non-specific adsorption. With respect to the former, it was found that the PEG surface chemistry strongly quenched the band-edge luminescence of CdSe/ZnS QDs and yielded significant band-gap luminescence. Furthermore, the PEG chemistry proved ineffective in preventing adsorption. With respect to hexanethiol capped CdSe/ZnS QDs, it was found that good QD luminescence was retained in organic solvent but was quenched in aqueous solution. The use of hydrophobic hexanethiol QDs in aqueous solution required the immobilization of QDs. To achieve this, we used thiol modified biotin and avidin coated fused silica optical fibers. Despite the quenching of the QDs, minimal adsorption was observed suggesting the methodology has good potential. In addition, we describe the development of a one-pot method for both the synthesis and capping of silicon QDs. Our approach also allows versatile post-synthetic modification of the silicon QD capping to produce a variety of functional groups. Silicon QDs are of interest in biosensing due to their biocompatibility and much lower toxicity compared to II-VI semiconductors.
The Evaluation of Two-stage Chemical Fractionation for the Enhanced Enzymatic Saccharification of Cellulose in Rice Straw

Rice straw, an agro-residue, can be utilized as a renewable resource for the production of fuel and chemicals. This study evaluates a two-stage chemical pretreatment (dilute acid hydrolysis followed by alkaline-peroxide delignification) for fractionation and enhancing the enzymatic saccharification of the rice straw cellulose to produce fermentable sugars. The process led to 100% hemicellulose dissolution and resulted in a solid residue with ~95% pure cellulose. Enzymatic saccharification of this cellulose liberates 70% more reducing sugars compared to other single-step pretreatment methods. The combined two-stage chemical pretreatment followed by enzymatic saccharification process resulted in 40.6 g/L reducing sugars from rice straw.
Phosphate interaction with uptake and leaf concentration of magnesium, calcium, and potassium in winter wheat seedlings

Low concentrations of Mg and Ca in cool-season grasses in late fall and early spring are a primary cause of grass tetany and wheat pasture poisoning in grazing cattle. Our objective was to investigate phosphate interaction with the uptake and leaf concentration of Mg, Ca, and K in winter wheat (Triticum aestivum L., cv. Larned) seedlings. Seedlings were grown hydroponically or in pots containing perlite with a solution containing nutrient element concentrations that mimicked the soil solution of a typical midwestern alfisol. Phosphate concentration of this solution was low so that wheat seedlings depleted solution p within a few hours (.)
Confocal imaging of chromatographic fouling under flow conditions

BACKGROUND: The fouling impact of selected fouling species was assessed by utilising confocal scanning laser microscopy (CSLM) to image a packed chromatographic bed during operation. A custom-made flow cell was packed with Q Sepharose FF and loaded with partially clarified E. coli homogenate. Selective, multicoloured fluorescent dyes were used to label a bovine serum albumin (BSA) test protein (Cy5.5), dsDNA (PicoGreen) and host cell proteins (HCPs) (Cy3). The fouling caused by the various fluorescently labelled components was visualised as a result of the fluorescence emitted by the PicoGreen-labelled dsDNA and the Cy3-labelled protein in the foulant stream, and by testing the adsorptive capacity of a test protein (BSA) onto the resin prior to and post-fouling as well as following the application of a common CIP procedure. RESULTS: Values for the effective diffusivity of BSA (De) were derived from the confocal images and the fouling impact was assessed by comparing De values obtained from different fouling scenarios. Under the most extreme conditions examined, fouling caused a 20% reduction in capacity compared to a fresh bed. BSA diffusivity did not appear to be affected by the fouling conditions studied. Sequential CIP using 15 CVs of 1 mol L−1 NaCl then 15 CVs of 1 mol L−1 NaOH was shown to be effective in removing nucleic acids and HCPs. Subsequent BSA adsorption showed that the CIP regime successfully restored the column capacity to its original value. In contrast, 15 CVs of 1 mol L−1 NaCl were ineffective in removing dsDNA but substantially removed HCPs. CONCLUSION: CSLM was demonstrated to be a useful tool for visualising fouling mechanisms. Comparing the results obtained by this technique using different modes of chromatographic operation provided insights into the fouling characteristics of finite baths versus packed beds. Copyright © 2007 Society of Chemical Industry
Biosorption of Cu(II) onto agricultural materials from tropical regions

BACKGROUND: In Ghana, the discharge of untreated gold mine wastewater contaminates the aquatic systems with heavy metals such as copper (Cu), threatening ecosystem and human health. The undesirable effects of these pollutants can be avoided by treatment of the mining wastewater prior to discharge. In this work, the sorption properties of agricultural materials, namely coconut shell, coconut husk, sawdust and Moringa oleifera seeds for Cu(II) were investigated. RESULTS: The Freundlich isotherm model described the Cu(II) removal by coconut husk (R2 = 0.999) and sawdust (R2 = 0.993) very well and the Cu(II) removal by Moringa oleifera seeds (R2 = 0.960) well. The model only reasonably described the Cu(II) removal by coconut shell (R2 = 0.932). A maximum Cu(II) uptake of 53.9 mg g−1 was achieved using the coconut shell. The sorption of Cu(II) onto coconut shell followed pseudo-second-order kinetics (R2 = 0.997). FTIR spectroscopy indicated the presence of functional groups in the biosorbents, some of which were involved in the sorption process. SEM-EDX analysis confirmed an exchange of Mg(II) and K(I) for Cu(II) on Moringa oleifera seeds and K(I) for Cu(II) on coconut shell. CONCLUSION: This study shows that coconut shell can be an important low-cost biosorbent for Cu(II) removal. The results indicate that ion exchange, precipitation and electrostatic forces were involved in the Cu(II) removal by the biosorbents investigated. Copyright © 2011 Society of Chemical Industry
Applications of Solid-State NMR to the Study of Organic/Inorganic Multicomponent Materials

Abstract The characterization of a variety of organic/inorganic multicomponent materials (OIMM) through solid-state NMR (SSNMR) spectroscopy will be reviewed. Many examples of applications to OIMM will be described, based on the observation of different nuclei and the use of various SSNMR methods, such as 1D and 2D techniques, measurements on relaxation and spin diffusion processes. OIMM are a very general category of systems differing, for example, by chemical nature and relative amount of organic and inorganic components, shape and size of the domains, and type of organic-inorganic interface. Some of the most investigated classes of OIMM are organically modified silicates, polymer/clay composites, polymer/inorganic filler systems, polymer electrolytes, stationary chromatographic phases, zeolites, and mesoporous silicas including small organic molecules. The aspects most efficiently investigated by SSNMR and discussed in this review include physical and/or chemical interactions occurring at the organic-inorganic interface, structural and dynamic behavior of the organic components, and dimensions and dispersion of organic and inorganic domains.
The effect of climate change on urban drainage: an evaluation based on regional climate model simulations

That we are in a period of extraordinary rates of climate change is today evident. These climate changes are likely to impact local weather conditions with direct impacts on precipitation patterns and urban drainage. In recent years several studies have focused on revealing the nature, extent and consequences of climate change on urban drainage and urban runoff pollution issues. This study uses predictions from a regional climate model to look at the effects of climate change on extreme precipitation events. Results are presented in terms of point rainfall extremes. The analysis involves three steps: Firstly, hourly rainfall intensities from 16 point rain gauges are averaged to create a rain gauge equivalent intensity for a 25 × 25 km square corresponding to one grid cell in the climate model. Secondly, the differences between present and future in the climate model is used to project the hourly extreme statistics of the rain gauge surface into the future. Thirdly, the future extremes of the square surface area are downscaled to give point rainfall extremes of the future. The results and conclusions rely heavily on the regional model's suitability in describing extremes at time-scales relevant to urban drainage. However, in spite of these uncertainties, and others raised in the discussion, the tendency is clear: extreme precipitation events effecting urban drainage and causing flooding will become more frequent as a result of climate change.
Biopolymer Conformational Distributions from Solid-State NMR: α-Helix and 310-Helix Contents of a Helical Peptide

A new approach to the quantitative experimental analysis of conformational distributions in partially ordered biopolymers is described and used to determine the fractional contents of α-helical, 310-helical, and random coil components in the conformational distributions of a 17-residue helix-forming peptide [Marqusee, S. ; Baldwin, R. L. Proc. Natl. Acad. Sci., U.S.A. 1987, 84, 8898−8902]. The approach is based on solid-state NMR measurements that probe φ and ψ dihedral angles at specific isotopically labeled sites, in particular two-dimensional magic-angle spinning NMR exchange spectra, carried out on glass-forming frozen solutions in glycerol/water. The data analysis employs a combination of constrained molecular dynamics simulations, to generate model dihedral angle distributions, and Bayesian statistics, to permit a quantitative determination of the relative probabilities of the possible fractional contents of α-helical, 310-helical, and random coil components. The peptide is found to be highly α-helic.
Synthesis of dimethyl carbonate in supercritical carbon dioxide

The reactivity of carbon dioxide with methanol to form dimethyl carbonate was studied in the presence of the n-butylmethoxytin compounds n-Bu3SnOCH3, n-Bu2Sn(OCH3)2 , and [n-Bu2(CH3O)Sn]2 O. The reaction occurred under solventless conditions at 423 K and was produced by an increase in CO2 pressure. This beneficial effect is primarily attributed to phase behavior. The mass transfer under liquid-vapor biphasic conditions was not limiting when the system reached the supercritical state for a CO2 pressure higher than 16 MPa. Under these conditions, CO2 acted as a reactant and a solvent.
Synthesis of Zeolitic Material from Waste Sandstone Cake Using Alkali Fusion

During quarrying of sandstone, waste sandstone cake is discharged as industrial waste. We attempted to convert the cake into zeolitic materials using the alkali fusion method. Waste sandstone cake is mainly composed of crystalline phases, which were difficult to dissolve into aqueous alkali solution. By alkali fusion, most of the crystalline phases were converted into soluble phases, and could be transformed into zeolite crystals, zeolite-X and hydroxysodalite. The cation exchange capacities (CECs) of the product was almost 2.3 mmol/g, which is about 30 times higher than that of waste cake, and is higher than that of commercial natural zeolite.
Heterometal Incorporation in Metal-Exchanged Zeolites Enables Low-Temperature Catalytic Activity of NOx Reduction

A series of new heterobimetallic zeolites has been synthesized by incorporating a secondary metal cation M (Sc3+, Fe3+, In3+, and La3+) in Cu-exchanged ZSM-5, zeolite-β, and SSZ-13 zeolites under carefully controlled experimental conditions. Characterization by diffuse-reflectance ultraviolet–visible spectroscopy (UV–vis), X-ray powder diffraction (XRD), extended X-ray absorption fine structure spectroscopy (EXAFS), and electron paramagnetic resonance spectroscopy (EPR) does not permit conclusive structural determination but supports the proposal that M3+ is hosted in zeolite structures in the vicinity of Cu(II), resulting in high NOx conversion activity at 150 °C. Among various zeolites reported here, CuFe-SSZ-13 offers the best NOx conversion activity in the 150–650 °C range and is hydrothermally stable when tested under accelerated aging conditions. Mechanistic studies employing stopped-flow diffuse reflectance FT-IR spectroscopy (DRIFTS) suggest that the high concentration of NO+ generated by heterobi.
Electroanalytical Determination of Lidocaine in Pharmaceutical Preparations Using Boron‐Doped Diamond Electrodes

A new electroanalytical procedure was developed for the determination of lidocaine in commercial local anesthetics products containing lidocaine as the active ingredient. The procedure is based on the use of electrochemical methods as cyclic and square-wave voltammetry, with boron-doped diamond electrodes. The oxidation of lidocaine in Britton–Robinson buffer (0.1 mol L−1) using this type of electrode gives rise to one irreversible peak in 1.68 V (versus Ag/AgCl). The detection and quantification limits obtained from pure water were 10.0 and 34.4 μg/L, respectively. The proposed electrochemical method was also successfully applied to the analysis of commercially available pharmaceutical preparations. The electrochemical responses of pharmaceutical preparations (gels) were identical to those of standard lidocaine. No influence of propyleneglycol present in the gels on the voltammetric responses was observed. Lidocaine recoveries ranged from 97.6% to 99.2%.
Efficiency enhancement in solid dye-sensitized solar cell by three-dimensional photonic crystal

Dye-sensitized solar cells (DSSCs) offer an attractive alternative to conventional solar cells because of their lower production cost. However, the liquid electrolyte used in these cells is unstable because of solvent leakage or evaporation, and DSSCs that use a solid electrolyte do not perform as well. In this paper, we present a design in which a nanocrystal (nc)-TiO2 underlayer is integrated with an optically active porous three dimensional photonic crystals (3D PCs) overlayer, and a sequential infiltration process is adopted to introduce additives to the solid electrolyte. This architecture allows effective dye sensitization, electrolyte infiltration, and charge collection from both the nc-TiO2 and the PC layers, yielding enhanced absorption in a specific spectral region. We describe the fabrication process and demonstrate the improved performance of the fabricated DSSCs, which exhibited conversion efficiencies that were as much as 32% higher than those of a conventional DSSC. This approach should be useful in solid-state devices where pore infiltration is a limiting factor, as well as in weakly absorbing photovoltaic devices.
Resonance Light Scattering Study on the Formation of a Manganese (II) Coordination Supramolecular Polymer and Its Analytical Application

The formation of a manganese (II) coordination supramolecular polymer was studied by resonance light scattering spectra for manganese (II) detection. Bis-sulfosalophen (a ditopic tetradentate Schiff base ligand) and bis-phenanthroline-glutaraldehyde (a ditopic bidentate ligand) were prepared for the construction of the supramolecular polymer. In a procedure of manganese (II) detection, manganese (II) ion reacts with bis-sulfosalophen to form a binuclear manganese (II) complex. The binuclear complex then self-assembles with bis-phenanthroline-glutaraldehyde to form the supramolecular polymer, resulting in the production of strong resonance light scattering signal. The amount of manganese was detected by measuring the resonance light scattering intensity. Under optimal conditions, a linear range was found to be 0.5–50.0 ng/mL, with a detection limit of 0.1 ng/mL. The method has been successfully applied to determine manganese in vegetable and tea samples with relative standard deviations of less than 5% and recoveries of 95.8–105.7%.
Determination of fluid-particle convective heat transfer coefficient

Fluid-to-particle convective heat transfer coefficient (hfp) was determined by continuous particle center temperature measurements in a hold tube by a temperature sensor system using the transmitter particle technique. The fluid used was carboxy methyl cellulose (CMC) at concentrations of 0.5, 1.0, and 1.2% (w/w). The carrier fluid temperatures were 22.22°, 65.56°, 76.67°, and 82.22° C. Temperature dependent viscosity parameters of CMC were determined and used in calculating hfp. Specific heat and thermal resistance of the sensor were experimentally determined and used in solving the energy balance equation to obtain hfp values. Values of hfp ranged from 108.08 to 195.83 W/m2° C. The results are expressed as a correlation of dimensionless numbers. The fluid viscosity significantly affected hfp at high temperatures. Decreasing fluid viscosity (by increasing fluid temperatures) increased hfp.
Luminescent CuInS2 quantum dots by partial cation exchange in Cu2- xS nanocrystals

Here, we show successful partial cation exchange reactions in Cu2–xS nanocrystals (NCs) yielding luminescent CuInS2 (CIS) NCs. Our approach of mild reaction conditions ensures slow Cu extraction rates, which results in a balance with the slow In incorporation rate. With this method, we obtain CIS NCs with photoluminescence (PL) far in the near-infrared (NIR), which cannot be directly synthesized by currently available synthesis protocols. We discuss the factors that favor partial, self-limited cation exchange from Cu2–xS to CIS NCs, rather than complete cation exchange to In2S3. The product CIS NCs have the wurtzite crystal structure, which is understood in terms of conservation of the hexagonal close packing of the anionic sublattice of the parent NCs into the product NCs. These results are an important step toward the design of CIS NCs with sizes and shapes that are not attainable by direct synthesis protocols and may thus impact a number of potential applications.
Multiple photon excited SF6 interaction with silicon surfaces

Infrared laser induced SF6–silicon interactions have been studied and the surface reaction yields have been determined as a function of the laser frequency, the laser intensity, and the gas pressure in both perpendicular and parallel beam incidences on the solid surfaces. The results clearly show that vibrationally excited SF6 molecules promoted by CO2 laser pulses are very reactive to silicon, particularly when the solid is simultaneously exposed to the intense ir radiation. The laser excitation of the Si substrate alone cannot cause the heterogeneous reaction to occur. The present gas–solid system thus provides an example which clearly establishes the direct correlation between surface reactivity and vibrational activation. Additional experimental measurements also demonstrate that the thermal fluorine atoms generated by SF6 multiple photon dissociation at high laser intensities can react with silicon to form volatile product. The study thus provides further insight into the silicon–fluorine reaction dy.
Rapid Analysis of Trace Gases in Complex Mixtures Using Selected Ion Flow TubeMass Spectrometry

Although the human nose is an extremely sensitive olfactory organ, detecting some odoriferous compounds at concentrations as low as a few ppt (parts per trillion by volume) it is not quantitative. Furthermore, it cannot identify some volatile species at quite high concentrations, and neither can it recognize the individual components of many mixtures of trace volatile organic compounds (VOCs). For some considerable time the scientific community has experimented with a number of different types of olfactory devices with varying degrees of success. The advent of selected ion flow tubemass spectrometry (SIFT-MS) has revolutionized thinking in trace gas monitoring due to the simplicity of operation together with the rapidity and sensitivity of detection that this technique provides.
Intermolecular Coupling in Liquid and Crystalline States of trans-N-Methylacetamide Investigated by Polarized Raman and FT-IR Spectroscopies

The isotropic and anisotropic Raman spectra of neat N-methylacetamide (NMA) at different temperatures between −10 and 60 °C and NMA in acetonitrile were measured in order to spectroscopically compare and characterize the crystallized (T < 28 °C) and liquid states. These plus infrared data were subjected to a self-consistent component band analysis. We found that the amide I band is composed of two subbands in the solid phase and three in the liquid phase. For the former, the subbands at 1633 and 1656 cm-1 arise from transition dipole coupling interactions associated with the Ag and B2g species of the crystal unit cell. Depolarization ratio measurements suggest a departure from strict D2h symmetry. The three subbands in the liquid phase reflect different aggregate structures. The lowest frequency band at 1634 cm-1 results from an NMA oligomer exhibiting a structure similar to that observed in the ordered crystal phase. The most intense subband shows a significant negative noncoincidence effect, its isotrop.
Artificial (military) intelligence: enabling decision dominance through machine learning

Decision dominance—a Commander’s ability to see, think, understand, and act first—becomes exponentially more important in multi-domain operations (MDO) where the lethality and pace of warfare increase. At the heart of decision dominance is intelligence analysis. Intelligence analysis provides an understanding of the threat and environment that forms the foundation for Commanders’ decisions throughout planning and execution. Artificial intelligence and machine learning (AI/ML) offer opportunities to automate portions of the intelligence process. Accordingly, this paper explores mechanisms to employ machine learning (ML) techniques to rapidly synthesize heterogeneous text data into knowledge that can be graphically depicted in a situation template (SITEMP). Specifically, the paper examines the feasibility of two approaches. The first leverages hierarchical, agglomerative clustering with subsequent classification. This approach is analogous to how an analyst unfamiliar with the environment would operate—seeking patterns in the data to develop a fused understanding. The second approach applies a few-shot learning methodology that is akin to an analyst recognizing reporting based on prior experience. While AI/ML is not a panacea, it does promise significant gains to the competitor that can leverage it first and most fully. Ultimately, this paper seeks to inspire novel applications of AI/ML technologies to combat the challenges expected in MDO.