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As infrastructure develops and adoption of smart water meters increases, new techniques are needed to validate and learn from the large datasets they produce. Patterns of leading digits (i.e., first non-zero digits, 1 through 9) can support this task. This study examines leading digits in hourly smart meter readings from a western U.S. water utility with over 5,000 customer connections. Benford analysis, power law analysis, and leading-digit-frequency analysis all indicate that the readings tend toward values that start with 1. The findings suggest that readings from smart water meters - and, by extension, water use by individual customers - could be expected to follow a particular nonuniform pattern of leading digits and that deviation from the pattern may indicate data errors or abnormal water use. Applications are suggested for validating water use data, comparing multiple datasets, checking projections, and assessing meter performance. Additional work is needed to further explore the beneficial uses of leading-digit patterns and other data signatures in water use data from diverse datasets.

This study examined whether program climate factors, stressors, demographic, and institutional variables were associated with doctoral students’ clinically significant generalized anxiety disorder ...

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Hypothesis: The hyperbranched chains on the tail of low surface energy surfactants (LSES) causes lowering of surface free energy and rock wettability alteration, offering significant improvement in oil recovery in asphaltene oil reservoirs. Experiments: Oil sweep efficiency was determined by fluid displacement in pure brine and LSES-brine solutions in a microfluidic pattern that was representative of a sandstone cross-section. Interfacial tension (IFT), wettability alteration, Raman and X-ray photoelectron spectroscopy (XPS) were used to measure the changes of asphaltene interactions with oil-aged substrate after surface treating with brine and surfactant-brine solutions. Findings: The hyperbranched LSES yielded a significant increase in the original-oil-in-place (OOIP) recovery (58%) relative to brine flooding (25%), even in the presence of asphaltene. Raman spectra showed the LSES-brine solutions to be capable of causing change to the asphaltene aggregate size after centrifugation treatment.

In this study, platinum (Pt) supported on titanium (Ti) mesh catalysts for catalytic hydrogen combustion were prepared by depositing Pt as a thin-layer on metallic or calcined Ti mesh. The Pt thin-layer could be stabilized as uniformly distributed, near nano-sized particles on the surface of calcined Ti mesh by exposing the freshly sputtered Pt to hydrogen. Temperatures between 478 and 525 °C were reached during hydrogen combustion and could be maintained at a hydrogen flow rate of 0.4 normal liter (Nl)/min for several hrs. It was determined that Ti mesh calcination at ≥900 °C formed an oxide layer on the surface of Ti wires, which prevented significant Pt aggregation. X-ray photoelectron spectroscopy revealed that the surface of Ti mesh was fully converted to TiO2 at ≥900 °C. Raman spectroscopy showed that the majority of TiO2 was present in the rutile phase, with some minor contribution from anatase-TiO2. The calcined Ti support was stable through all investigations and did not indicate any signs of degradation.

Besides collecting legitimate wastewater, municipal sanitary sewer systems, even when separated from storm sewer systems, also receive unwanted inflow and infiltration (I/I) that adversely ...

Metal sulphides, including zinc sulphide (ZnS), are semiconductor photocatalysts that have been investigated for the photocatalytic degradation of organic pollutants as well as their activity during the hydrogen evolution reaction and water splitting. However, devising ZnS photocatalysts with a high overall quantum efficiency has been a challenge due to the rapid recombination rates of charge carriers. Various strategies, including the control of size and morphology of ZnS nanoparticles, have been proposed to overcome these drawbacks. In this work, ZnS samples with different morphologies were prepared from zinc and sulphur powders via a facile hydrothermal method by varying the amount of sodium borohydride used as a reducing agent. The structural properties of the ZnS nanoparticles were analysed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) techniques. All-electron hybrid density functional theory calculations were employed to elucidate the effect of sulphur and zinc vacancies occurring in the bulk as well as (220) surface on the overall electronic properties and absorption of ZnS. Considerable differences in the defect level positions were observed between the bulk and surface of ZnS while the adsorption of NaBH

Online AI symptom checkers and diagnostic assistants (DAs) have tremendous potential to reduce misdiagnosis and cost, while increasing the quality, convenience, and availability of healthcare, but only if they can perform with high accuracy. We introduce a novel Bayesian DA designed to improve diagnostic accuracy by addressing key weaknesses of Bayesian Network implementations for clinical diagnosis. We compare the performance of our prototype DA (MidasMed) to that of physicians and six other publicly accessible DAs (Ada, Babylon, Buoy, Isabel, Symptomate, and WebMD) using a set of 30 publicly available case vignettes, and using only sparse history (no exam findings or tests). Our results demonstrate superior performance of the MidasMed DA, with the correct diagnosis being the top ranked disorder in 93% of cases, and in the top 3 in 96% of cases.

Frostbite and other cold-related injuries commonly develop during prolonged exposure to the low environmental temperatures of polar and mountainous regions. Hypoxia is a potent sympathetic stimulus that causes vasoconstriction of the peripheral blood vessels, which may further compound the risk of developing a cold-related injury during high-altitude exposure. To investigate this, we utilized portable infrared thermographic technology to quantitatively measure changes in the surface temperature of the hands during exposure to increasing levels of normobaric hypoxia in a temperature-controlled high-altitude simulation. Surface temperature was assessed at four anatomical locations on both the left and right hands in a cohort of 10 healthy male participants at a series of predetermined levels of hypoxia (0.20 fraction of inspired oxygen [F

Due to the prohibitive financial expense and logistical difficulties of a wholesale changeover from natural gas to hydrogen, hydrogen-enriched natural gas (HENG) offers a more viable intermediate solution for offsetting the carbon dioxide output of domestic gas usage and reducing the blow-out susceptibility of natural gas flames. In order to formulate a practically useful description of the blow-out threshold, the present work addresses the minimum energy per unit volume of premixed gas required for the sustained combustion of HENG fuels with molar hydrogen concentrations between zero and 50 mol%. By considering a ring burner comprising circular burner jet apertures with diameters in the range 1.0–2.4 mm, this critical energy density was demonstrated to increase linearly with the mean velocity of the admitted gas premixture, approaching a value that was common to all of the investigated HENG compositions in the limit of zero flow. Furthermore, despite flame morphology varying substantially as a function of flow conditions, the visible surface area of critically stable flames consistently exhibited an empirical squared dependence on the power generated by combusting fuel. By combining these correlations, the onset of blow-out was shown to be well-approximated by a formula that relates the critical surface-averaged laminar burning velocity to the mean velocity of gas molecules at the burner jet. This model provides a simplified means of predicting blow-out conditions from measurable input parameters and could serve as an invaluable asset for the design of new HENG burner systems or the retrofitting of existing natural gas appliances.

Producing thermoelectric materials without energy-intensive processes is essential to reduce the production costs and for wide-scale applications. Copper sulfides have recently been identified as n...

Eight new fluorescent conjugated polymers were synthesized by the Suzuki polycondensation reaction of 9,9-dioctylfluorene-2,7-diboronic acid bis(1,3-propanediol) ester and a conjugated dihalogenated monomer. The photophysical properties of these polymers were investigated as well-dissolved solutions in chloroform and as nanoparticle suspensions in water. Several of the polymers had large Stokes shifts (greater than 100 nm) and others demonstrated unique changes in the fluorescence properties in aggregated verse nonaggregated forms. Preliminary applications of these polymers in the detection of common bisphenols are also reported.

A 1% Ru/C catalyst prepared by the sol immobilization method showed a high yield of γ-valerolactone from levulinic acid. We performed an optimization of the catalyst by varying the preparation variables involved in the sol immobilization method and detremined that the ratio of PVA, NaBH4 to Ru and heat treatment conditions play a crucial role in the synthesis of active and selective catalysts. By varying these parameters we have identified the optimum conditions for catalyst preparation by providing well dispersed nanoparticles of RuOx on the carbon support that are reducible under low reaction temperature and in turn gave an enhanced catalytic activity. In contrast to a catalyst prepared without using a PVA stabiliser, the use of a small amount PVA (PVA/Ru = 0.1) provided active nanoparticles, by controlling the steric size of the Ru nanoparticles. An optimum amount of NaBH4 was required in order to provide the reducible Ru species on the surface of catalyst and further increase in NaBH4 was found to cause a decline in activity that was related to the kinetics of nanoparticle formation during catalyst preparation. A variation of heat treatment temperature showed a corresponding decrease in catalytic activity linked with the sintering and an increase in particle size.

We have investigated xNi–yCu–ZrO2 catalysts for the selective synthesis of γ-valerolactone from levulinic acid (LA). A series of xNi–yCu–ZrO2 catalysts with a consistent metal loading of 50% but varying Ni and Cu composition were prepared by an oxalate gel precipitation method and tested for LA hydrogenation. Ni-rich catalysts showed higher catalytic activity compared with Cu-rich formulations with a 45Ni–5Cu–ZrO2 composition yielding 76% γ-valerolactone after a reaction time of 30 min at 200 °C. Characterisation of the materials by XRD, surface area measurements and TPR allow us to attribute the differences in performance seen for different compositions to particle size and nanoparticle dispersion effects. DFT calculations also showed that a shift of d-band centre to higher energies with the mole fraction of Ni in Cu–Ni alloys would be expected to lead to improved hydrogen dissociation in Ni-rich catalysts and so aid hydrogenation activity.

The electromigration behaviour of raw and acid purified single walled carbon nanotubes (SWCNTs) in dilute aqueous systems (0.0034 mg mL-1), in the absence of surfactant, with the addition of either 0.85 M acetic acid or 0.1 M CuSO4, was evaluated using a 2-inch copper cathode and either a 2-inch copper or 0.5-inch platinum anode. The results showed that the electromigration of raw SWCNTs (with a high catalyst residue) in the presence of CuSO4 resulted in the formation of a Cu-SWCNT composite material at the cathode. In contrast, acid purified SWCNTs were observed to diffuse to a copper anode, creating fibrillated agglomerates with "rice-grain"-like morphologies. Upon acidification with acetic acid (or addition of CuSO4) the direction of electromigration reversed towards the cathode as a result of coordination of Cu2+ to the functional groups on the SWCNT overcoming the inherent negative charge of the acid purified SWCNTs. The result was the co-deposition of SWCNTs and Cu metal on the cathode. Addition of 0.005 M EDTA sequesters some of the Cu2+ and resulted in the separation of metal decorated SWCNTs to the cathode and un-decorated SWCNTs to the anode. The resulting SWCNT and Cu/SWCNT deposits were characterized by Raman spectroscopy, XPS, SEM, EDS, and TEM.

In the effort to reduce carbon emissions from an ever-increasing global population, it has become increasingly vital to monitor and counteract the environmental impact of our domestic energy usage given its contribution to overall carbon emissions. To this end, hydrogen has emerged as a foremost candidate to offset and eventually replace the use of traditional gaseous fossil fuels. Hydrogen as the universal energy carrier or vector is easily produced from all forms of renewable or recovered energy as a storable, transportable commodity that can be used on demand, thus decoupling the supply from demand that is often considered to be the down-side of intermittent renewable energy usage. European trials have already been conducted to investigate the practical implementation of hydrogen-enriched natural gas (HENG) within a mains gas supply. In this work, the limitations of such a strategy are evaluated based on a novel meta-analysis of experimental studies within the literature, with a focus on the constraints imposed by the phenomena of flash-back and blow-off. Through consideration of the Wobbe Index, we discuss the relationship between molar hydrogen percentage and annual carbon dioxide output, as well as the predicted effect of hydrogen-enrichment on fuel costs. It is further shown that in addition to suppressing both blow-off and yellow-tipping, hydrogen-enrichment of natural gas does not significantly increase the risk of flash-back on ignition for realistic burner setups, while flash-back at extinction is avoided for circular port diameters of less than 3.5 mm unless the proportion of hydrogen exceeds 34.7 mol%. It is thus proposed that up to 30 mol% of the natural gas supply may be replaced in the UK with guaranteed safety and reliability for the domestic end-user, without any modification of the appliance infrastructure.

SUMMARY Epigenetic modifications control the stability and translation of mRNA molecules. Here, we present a microscopy-based platform for quantifying modified RNA molecules and for relating the modification patterns to single-cell phenotypes. We directly capture mRNAs from cell lysates on oligo-dT-coated coverslips, then visually detect and sequence individual m6A-immunolabled transcripts without amplification. Integration of a nanoscale device enabled us to isolate single cells on the platform, and thereby relate single-cell m6A modification states to gene expression signatures and cell surface markers. Application of the platform to MUTZ3 leukemia cells revealed a marked reduction in cellular m6A levels as CD34+ leukemic progenitors differentiate to CD14+ myeloid cells. We then coupled single-molecule m6A detection with fluorescence in situ hybridization (FISH) to relate mRNA and m6A levels of individual genes to single-cell phenotypes. This single-cell multi-modal assay suite can empower investigations of RNA modifications in rare populations and single cells., Graphical abstract, In brief Kim et al. develop a microscopy-based platform for epitranscriptome profiling, compatible with low-input samples and single cells. The platform provides multi-modal measurements of cell surface markers, gene expression, and m6A RNA modification. The system is flexible and can be applied to study various RNA modifications and their dynamics in heterogeneous cell mixtures.

BACKGROUND The selective conversion of cellulose to gluconic acid under mild conditions is challenging as it has abundant intra-and inter-molecular hydrogen bonds that protect the β-1,4-glycosidic bonds and make it intrinsically recalcitrant to deploymerize. RESULTS Au-Pd/TiO2 and Au-Pt/TiO2 catalysts prepared by sol immobilization method without pre-treatment are active and selective for the oxidation of glucose and cellobiose to gluconic acid under base-free conditions. Important preparation parameters are the pre-treatment of the catalyst and the metal ratio. CONCLUSION The optimized catalyst provided a good yield of gluconic acid from cellobiose and has opened up a new catalyst system for cellobiose conversion in terms of a heterogeneous catalyst.

Cu–ZrO2 catalysts were synthesized by the methanothermal (Me) and oxalate gel precipitation (Og) methods. Detailed characterization of the catalysts synthesized by the Me method shows that these contain only Cu substituted into the tetragonal ZrO2 lattice. For catalysts prepared using the Og method Cu is found not only in the tetragonal ZrO2 lattice but also in the form of CuO particles on the zirconia surface. When these materials were tested for the hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) it was found that Me materials show no catalytic activity, whereas GVL was formed using Og catalysts. A reduction treatment of the Og catalysts prior to use resulted in a marked increase in the catalytic activity, however, no activity increase was observed when the Me material was exposed to a similar treatment before testing. Based on these results and characterization data, we conclude that the catalytically active component of Cu–ZrO2 catalysts for the hydrogenation of LA is reduced Cu particles dispersed on the catalyst surface with strong interaction with the Cu incorporated zirconia support, while the role of Cu in the zirconia lattice is to improve the adhesion of these particles and maintain their dispersion.

Conjugated polymers (CPs) are widely used for a variety of applications as a result of their high quantum yields, strong extinction coefficients, and good stability to a variety of experimental conditions. In many cases, the use of conjugated polymer nanoparticles (CPNs) provides additional practical advantages. The ability to understand how the structure of the CP affects its photophysical properties has the potential to significantly accelerate research in this area. In this work we examine 3 CPs, including two novel polymer architectures, and evaluate how the structures of the conjugated side chains affect the photophysical properties of the free polymer chains as well as the properties of aggregated CPNs. Both the linker identity and the terminal aromatic rings of the side chains were found to affect the photophysical properties of the CPs, with the terminal groups leading to the most substantial changes in photophysical properties in all of the polymeric forms (well-solubilized in organic solvent and aggregated in nanoparticles).

Control and management of invasive plants frequently differs from agricultural weed control as plant establishment and development progresses in less intensively managed systems. This is particularly the case for rhizome-forming invasive plants, such as Japanese knotweed (Fallopia japonica var. japonica) as minimum disturbance regimes permit the accumulation of significant below ground reserves that allow recovery from many physical, biological, chemical and integrated control methods. Here, we review the ongoing work of Jones, who established the world's largest and longest running invasive knotweed field trial. Using an integrated weed management (IWM) approach to testing, this research evaluated 19 different control treatments over three years to minimise pesticide use and increase the sustainability of controlling this ecologically and economically damaging species. Through consideration of plant biology, it was found that glyphosate-based herbicide treatments that exploited phenological changes in rhizome source-sink were significantly more effective than all other treatments. These results provide a roadmap to the more effective and efficient control of rhizome-forming invasive plants and emphasise the importance of scale appropriate empirical evidence to inform regulators when considering non-agricultural weed control. Within intensively managed arable agricultural systems, weed control is directed toward immature annual and perennial plants, during a 'critical period' extending for a relatively short time after crop emergence. This is because at this time, resource depletion by weed species may exert a major negative effect upon crop yield. Agronomic weed management may be achieved using a range of weed control methods, including: cultural/preventative (e.g. soil cultivation, disrupting weed establishment), physical (mechanical methods or hand weeding), biological (biocontrol or bioherbicides), chemical (plant protection products; PPPs) and integrated weed management (IWM). True IWM systems combine cultural, physical, biological and/or chemical methods; integrated herbicide management systems use a range of PPPs to mitigate selection of resistant weed populations. In contrast, control of invasive weed species, or invasive alien plants (IAPs) is commonly undertaken in less intensively managed systems, or unmanaged areas such as abandoned agricultural land, riparian areas and brownfield sites. Here, IAPs tend to be large and well-established so that plant persistence and development processes are often unhindered by weed control methods typically applied in agriculture. This is particularly true of rhizome-forming invasive species, such as Japanese knotweed (Fallopia japonica var. japonica) where minimal disturbance regimes permit the long-term development of significant carbohydrate reserves within perennating rhizome organs below the soil surface (>50 cm). Storage reserves permit recovery from repeated intentional disturbance and biological control; while physical size, depth, resilience and strong seasonal changes in source-sink strength of such organs preclude effective chemical control using many herbicides, as insufficient herbicide active ingredient is accumulated within storage tissues. There are strong environmental, ecological and economic cases for the management of IAPs to minimise their negative impacts. However, invasive plant management is hindered by the absence of scale appropriate empirical evidence to support control method selection and plant traits which are effective against control, e.g. rhizome bud bank. Consequently, control programmes may have less than optimal results in terms of economic and environmental sustainability. Terminology is critically important when defining clear programme objectives (i.e. control, management, eradication) and long-term assessment of IAP control and post-treatment habitat recovery is needed to establish best practice. In the case of Japanese knotweed, an approach that works with the seasonal resource translocation between above- and below-ground biomass and adequate herbicide coverage is the key to success. Physical disruption of the plant or increasing use of herbicide application will not give better control and may be less effective and costly. There is increasing public concern (real and perceived) about the widespread use of herbicides, and glyphosate in particular, resulting in increased PPP deregulation and reduced concentration and application rates. Experimental data that define best practice are essential to inform regulators when considering non-agricultural weed control. While the use of PPPs to control perennial IAPs is relatively small, the detrimental environmental, economic and amenity impacts are significant, such that the loss of effective PPPs should be of concern. In the absence of glyphosate, the only effective alternative for Japanese knotweed control would be complete physical excavation and disposal which would be significantly more expensive and arguably more environmentally harmful due to increased associated CO2 emissions and the risk of further spread.

Highly sensitive gold nanoparticle decorated zinc oxide nanosheet gas sensors have been fabricated using simple and rapid chemical methods capable of producing a normalised current gain of 2.54 (at 10V) in dry air containing 2.5ppm of hydrogen gas at 200C and a current gain of 382.53 under 125ppm. Compared to undecorated sheet based sensors where a response of 1.24 was observed under 125ppm at 200C a massive relative increase in signal is observed. The zinc oxide nanosheets are produced via a previously reported simple microwave assisted hydrothermal growth method and gold nanoparticles with mean diameter of 5nm synthesized via a simple sodium borohydride reduction of hydrogen tetrachloroaurate in the presence of polyvinylpyrrolidone (PVP) followed by drop casting onto a pre-patterned aluminium oxide substrate.

Reported herein is the significant fluorescence enhancement of conjugated polymer nanoparticles in the presence of aromatic organochlorine pesticides. This pesticide-mediated fluorescence enhancement leads to reversible pesticide detection systems with high sensitivity (as low as 5 μM), as well as significant generality and straightforward reversibility.

A series of ruthenium catalysts supported on two different carbons were tested for the hydrogenation of lactic acid to 1,2-propanediol and butanone to 2-butanol. The properties of the carbon supports were investigated by inelastic neutron scattering and correlated with the properties of the ruthenium deposited onto the carbons by wet impregnation or sol-immobilisation. It was noted that the rate of butanone hydrogenation was highly dependent on the carbon support, while no noticeable difference in rates was observed between different catalysts for the hydrogenation of lactic acid.

A series of Cu–ZrO2 catalysts prepared by a co-precipitation method were studied for the hydrogenation of levulinic acid to give γ-valerolactone (GVL). The effects of a range of catalyst preparation parameters, namely molar Cu/Zr ratio, calcination temperature and the ageing time of the precipitates, were systematically investigated. The molar Cu/Zr ratio was found to have a strong influence on the BET surface area of the material leading to a high activity for catalysts prepared with a Cu/Zr molar ratio of unity. Using this molar ratio the calcination temperature was varied from 300 °C to 800 °C, the material calcined at 400 °C showed the highest activity. Increasing the ageing time used in the catalyst preparation identified 6 h as the optimum to achieve the highest activity for LA conversion. Based on characterisation of all materials we conclude that the active Cu species is present in only low concentration suggesting that it should be possible to produce a catalyst of high activity with much lower Cu content.

Through a facile solvothermal procedure, a CdS/WOx nanocomposite has been synthesised which exhibits photocapacitive behaviour under white light illumination at a radiant flux density of 99.3 mW cm−2. Photoelectrochemical experiments were undertaken to examine the self-charging properties of the material and to develop an understanding of the underlying electronic band structure responsible for the phenomenon. By employing XPS, UPS and UV-Vis diffuse reflectance spectroscopy for further characterisation, the ability of the composite to generate current following the removal of incident light was related to the trapping of photoexcited electrons by the WOx component. The presence of WOx yielded an order of magnitude increase in the transient photocurrent response relative to CdS alone, an effect attributed to the suppression of electron-hole recombination in CdS due to hole transfer across the CdS/WOx interface. Moreover, current discharge from the material persisted for more than twenty minutes after final illumination, an order of magnitude improvement over many existing binary composites. As a seminal investigation into the photocapacitive characteristics of CdS/WOx composites, the work offers insight into how the constituent materials might be utilised as part of a future self-charging solar device.

Utilization of an integrated forward osmosis-solar powered membrane distillation system can provide a promising method for brackish water desalination. In this study, the brackish water feed and fertilizer draw solutions were operated in a forward osmosis process to generate irrigation water for agriculture. Forward osmosis was also selected as membrane distillation pre-treatment to avoid fouling and wetting of the membrane distillation membrane. Subsequently, the diluted draw solutions were treated in the membrane distillation system to recover the initial osmotic pressure and to obtain a final distillate permeate. The experimental results revealed that the modified forward osmosis membrane exhibited slightly better performance in terms of maximum water flux, minimum reverse solute flux and high water recovery of 53.5%. In the membrane distillation process, an optimum water flux of about 5.7 L/m2. hr and high rejection rate of about 99.55% were achieved at an optimum temperature of 60 °C. Modelling was applied to investigate the feasibility of using a solar collector to power the membrane distillation system and hence limit energy costs. By using renewable energy, we calculate that the energy consumption of the hybrid system could be reduced by 67%. Membrane distillation-solar powered system can achieve optimum energy consumption recoded as 1.1 kWh. We concluded that the diluted fertilizer draw solution can be used as an irrigation water after further dilution by an available water source. By using forward osmosis prior to membrane distillation process, the membrane distillation membrane showed less fouling and wetting leading to excellent rejection rate and acceptable distillate permeate. The energy consumption of the forward osmosis-solar powered membrane distillation system was lower than that for reverse osmosis stand-alone system. The findings of this work could be used to develop guidelines for the optimal design of industrial forward osmosis-membrane distillation system.

ZnO nanosheets are polycrystalline nanostructures that are used in devices including solar cells and gas sensors. However, for efficient and reproducible device operation and contact behaviour the conductivity characteristics must be controlled and surface contaminants removed. Here we use low doses of argon bombardment to remove surface contamination and make reproducible lower resistance contacts. Higher doses strip the surface of the nanosheets altering the contact type from near-ohmic to rectifying by removing the donor-type defects, which photoluminescence shows to be concentrated in the near-surface. Controlled doses of argon treatments allow nanosheets to be customised for device formation.

The hydrogenation of lactic acid to form 1,2-propanediol has been investigated using Ru nanoparticles supported on carbon as a catalyst. Two series of catalysts which were prepared by wet impregnation and sol-immobilization were investigated. Their activity was contrasted with that of a standard commercial Ru/C catalyst (all catalysts comprise 5 wt % Ru). The catalyst prepared using sol-immobilization was found to be more active than the wet impregnation materials. In addition, the catalyst made by sol-immobilization was initially more active than the standard commercial catalyst. However, when reacted for an extended time or with successive reuse cycles, the sol-immobilized catalyst became less active, whereas the standard commercial catalyst became steadily more active. Furthermore, both catalysts exhibited an induction period during the first 1000 s of reaction. Detailed scanning transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption fine structure analysis data, when correlated with the catalytic performance results, showed that the high activity can be ascribed to highly dispersed Ru nanoparticles. Although the sol-immobilization method achieved these optimal discrete Ru nanoparticles immediately, as can be expected from this preparation methodology, the materials were unstable upon reuse. In addition, surface lactide species were detected on these particles using X-ray photoelectron spectroscopy, which could contribute to their deactivation. The commercial Ru/C catalysts, on the other hand, required treatment under reaction conditions to change from raft-like morphologies to the desired small nanoparticle morphology, during which time the catalytic performance progressively improved.

Arrays of CVD catalyst-free ZnO nanowires have been successfully grown without the use of seed layers, using both wet chemical and dry plasma etching methods to alter surface topography. XPS analysis indicates that the NW growth cannot be attributed to a substrate surface chemistry and is therefore directly related to the substrate topography. These nanowires demonstrate structural and optical properties typical of CVD ZnO nanowires. Moreover, the NW arrays exhibit a degree of vertical alignment of less than 20° from the substrate normal. Electrical measurements suggest an improved conduction path through the substrate over seed layer grown nanowires. Furthermore, the etching technique was combined with e-beam lithography to produce high resolution selective area nanowire growth. The ability to pattern uniform nanowires using mature dry etch technology coupled with the increased charge transport through the substrate demonstrates the potential of this technique in the vertical integration of nanowire arrays.

In this work, as-received HiPCO single walled carbon nanotubes (SWCNTs) are incorporated in a controllable manner at various concentrations into Cu-SWCNT composites via electroless plating, by varying the related reaction times, with polyethylene glycol (PEG) used as a dispersing agent. The resultant samples were analyzed using scanning electron microscopy (SEM) for morphology assessment, energy dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS) for elemental analysis, X-ray diffraction (XRD) for the assessment of crystal phase identification, and Raman spectroscopy for the confirmation of the presence of the incorporated SWCNTs. The Cu-SWCNT composites were found to contain carbon, catalytic iron (associated with the raw, as-received SWCNTs), oxygen, and copper, the latter was found to be inversely proportional to carbon and iron contents. The oxygen (associated with both the SWCNT defect sites and oxidized copper surfaces) remained more or less constant regardless of the proportion of SWCNTs in the composites. The Raman IG:ID ratio remains within the experimental error constant, indicating that the electroless deposition does not have a deleterious effect on the SWCNTs. At short deposition times, SEM revealed a relatively dense structure comprising a distinctive fibrous morphology, suggestive of an underlying SWCNT substrate coated with copper, however, with increasing deposition, a more porous morphology is observed. The size of the granular particles increases up until 10 min of reaction, after which time it remains unchanged.

The authors present the XPS survey and detailed element spectra of a copper-carbon nanotube composite synthesized in their laboratories. They compare the copper spectrum to a reference spectrum of copper(II) acetate measured under the same conditions to ascertain the chemical composition of the copper in the composite.

Viruses contribute to the mortality of marine microbes, consequentially altering biological species composition and system biogeochemistry. Although it is well established that host cells provide metabolic resources for virus replication, the extent to which infection reshapes host metabolism at a global level and the effect of this alteration on the cellular material released following viral lysis is less understood. To address this knowledge gap, the growth dynamics, metabolism and extracellular lysate of roseophage-infected Sulfitobacter sp. 2047 was studied using a variety of techniques, including liquid chromatography–tandem mass spectrometry (LC-MS/MS)-based metabolomics. Quantitative estimates of the total amount of carbon and nitrogen sequestered into particulate biomass indicate that phage infection redirects ∼75% of nutrients into virions. Intracellular concentrations for 82 metabolites were measured at seven time points over the infection cycle. By the end of this period, 71% of the detected metabolites were significantly elevated in infected populations, and stable isotope-based flux measurements showed that these cells had elevated metabolic activity. In contrast to simple hypothetical models that assume that extracellular compounds increase because of lysis, a profile of metabolites from infected cultures showed that >70% of the 56 quantified compounds had decreased concentrations in the lysate relative to uninfected controls, suggesting that these small, labile nutrients were being utilized by surviving cells. These results indicate that virus-infected cells are physiologically distinct from their uninfected counterparts, which has implications for microbial community ecology and biogeochemistry.

Pentasubstituted aromatic rings serve as templates for drug design and can be conveniently prepared by the thermolysis of suitably substituted alkynes under microwave conditions.

Data from the Community and Civic Engagement Module of the 2010 multi-institutional Student Experience in the Research University (SERU) survey were used to develop and test two structural equation models that estimated the potential direct and indirect effects of service-learning involvement on undergraduate students’ (n = 20,426) perceived gains in academic and sociocultural development. Service-learning was found to have a positive association with students’ citizenship/civic behaviors, both in- and out-of-class, but no statistically significant effect on students’ perceived gains in academic skills was found. The structural equation model also revealed statistically significant positive direct relationships between service-learning and student perceptions of sociocultural gains as well as between service-learning and students’ civic-oriented behaviors (both in- and out-of-class). Students’ citizenship and civic behaviors (both in- and out-of-class) were found to play a mediating role between service-learning and sociocultural outcomes.

Pentasubstituted aromatic rings serve as templates for drug design and can be conveniently prepared by the thermolysis of suitably substituted alkynes under microwave conditions.

Objective. We explore whether observed sex-based differences in political knowledge have an impact on men's and women's participation in six different political activities. Methods. Utilizing ANES data from the five presidential elections between 1984 and 2000, we employ logistic regression to estimate the likelihood of voting, influencing a vote, attending a political meeting, working on a political campaign, wearing a political button, and making a campaign donation. Results. At lower levels of political knowledge, women's lower political knowledge depresses their participation in politics. The participation gap disappears at higher levels of political knowledge for three participatory acts: attempting to influence a vote, attending a political meeting, and donating to a political campaign. Furthermore, at higher levels of political knowledge, women are more likely than men to vote, wear a political button, or work for political campaigns. Conclusion. Our analysis reveals that political knowledge differentially affects men's and women's political participation. These findings complement existing scholarship that finds women hold themselves to a higher standard before engaging in political activities such as running for elected office.

Current definitions of retention and graduation rates distort the picture of student success by limiting it to completion of a degree at the institution of entry. By incorporating data from the National Student Clearinghouse (NSC), a clearer picture emerges. The NSC data captures retention and graduation at both entry and transfer institutions. To accommodate this polychotomous definition of success, more sophisticated methods of modeling limited dependent variables are needed. Though multinomial logit is often considered the most accessible method, the strict assumptions it imposes may be inappropriate. We therefore compare multinomial regression techniques to assess their utility in modeling multi-institutional student success.

We computed the single molecule conductance of a series of linear α−ω-dithiolalkanes as a function of their conformation, following experimental evidence (Haiss et al. Faraday Discuss. 2006, 131, 253) that even these simple molecules exhibit a thermal gating of electron transfer. After performing a conformational search using the MM3 empirical force-field, for each conformation, we evaluated the conductance using DFT single point calculations and Green's function theoretical approach. We analyzed the complex dependence of the conductance on the conformation, discussing its correlation with the conformational energy and the molecule end-to-end distance. From this data, the temperature dependence of conductance was calculated. Our calculations confirm that the conformational flexibility of the alkylic chain led to a higher conductance at higher temperatures. Therefore, the electron transport in these junctions appears to be thermally activated even if it takes place by pure tunneling.

Parathyroid hormone (PTH) regulation of matrix metalloproteinase-13 ( MMP-13) expression in osteoblasts contributes to normal bone turnover. The PTH response region of the rat MMP-13 gene spans nucleotides (nt) −148 to −38 and supports binding of numerous transcription factors, including Runx2, necessary for osteoblast differentiation, c-Fos/c-Jun, and Ets-1. These trans-acting proteins mediate hormone induction via incompletely defined combinatorial interactions. Within this region, adjacent to the distal Runx2 site, is a homopolymeric(dA:dT) element (−119/−110 nt) that conforms to the consensus site for the novel transcription factor nuclear matrix protein-4/cas interacting zinc finger protein (Nmp4/CIZ). This protein regulates bone cell expression of type I collagen and suppresses BMP2-enhanced osteoblast differentiation. The aim of this study was to determine whether Nmp4/CIZ contributes to MMP-13 basal transcription and PTH responsiveness in osteoblasts. Electrophoretic mobility shift analysis confirms Nmp4/CIZ binding within the MMP-13 PTH response region. Mutation of the Nmp4/CIZ element decreases basal activity of an MMP-13 promoter-reporter construct containing the first 1329 nt of the 5′-regulatory region, and overexpression of Nmp4/CIZ protein enhances the activity of the wild-type promoter. The same mutation of the homopolymeric(dA:dT) element enhances the MMP-13 response to PTH and PGE2. Overexpression of Nmp4/CIZ diminishes hormone induction. Mutation of both the homopolymeric(dA:dT) element and the adjacent Runx2 site further augments the PTH response. On the basis of these data and previous studies, we propose that Nmp4/CIZ is a component of a multiprotein assemblage or enhanceosome within the MMP-13 PTH response region and that, within this context, Nmp4/CIZ promotes both basal expression and hormonal synergy.

Ti is often used to form an initial Ohmic interface between ZnO and Au due to its low work function, and the TiO2/ZnO heterojunction is also of great importance for many practical applications of nanoparticles. Here, Ti has been controllably deposited onto hydrothermally grown ZnO nanowires and the formation of metal-semiconductor contact has been investigated using x-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and scanning electron microscopy. XPS results showed that that the Ti initially reacts with surface oxygen species to form TiO2, and further deposition results in the formation of oxides with oxidation state numbers lower than four, and eventually metallic Ti on top of the TiO2. The formation of TiC was also observed. XPS showed that the onset of metallic Ti coincided with a Zn 3p core level shift to lower binding energy, indicating upwards band bending and the formation of a rectifying contact. Annealing caused a near-complete conversion of the metallic Ti to TiO2 and caused the Zn 3p to shift back to its original higher binding energy, resulting in downwards band bending and a more Ohmic contact. PL measurements showed that the optical properties of the nanowires are not affected by the contact formation.

We have developed a low-cost technique using a conventional microwave oven to grow layered basic zinc acetate (LBZA) nanosheets (NSs) from a zinc acetate, zinc nitrate and HMTA solution in only 2 min. The as-grown crystals and their pyrolytic decomposition into ZnO nanocrystalline NSs are characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), X-ray diffraction (XRD) and photoluminescence (PL). SEM and AFM measurements show that the LBZA NSs have typical lateral dimensions of 1 to 5 μm and thickness of 20 to 100 nm. Annealing in air from 200°C to 1,000°C results in the formation of ZnO nanocrystalline NSs, with a nanocrystallite size ranging from 16 nm at 200°C to 104 nm at 1,000°C, as determined by SEM. SEM shows evidence of sintering at 600°C. PL shows that the shape of the visible band is greatly affected by the annealing temperature and that the exciton band to defect band intensity ratio is maximum at 400°C and decreases by a factor of 15 after annealing at 600°C. The shape and thickness of the ZnO nanocrystalline NSs are the same as LBZA NSs. This structure provides a high surface-to-volume ratio of interconnected nanoparticles that is favorable for applications requiring high specific area and low resistivity such as gas sensing and dye-sensitized solar cells (DSCs). We show that resistive gas sensors fabricated with the ZnO NSs showed a response of 1.12 and 1.65 to 12.5 ppm and 200 ppm of CO at 350°C in dry air, respectively, and that DSCs also fabricated from the material had an overall efficiency of 1.3%. PACS 81.07.-b; 62.23.Kn; 61.82.Fk