Quantitative evaluation of released nanomaterials from carbon nanotube epoxy nanocomposites during environmental exposure and mechanical treatment.

Carbon nanotubes (CNTs) are promising nanomaterials exhibiting high thermal and electrical conductivities, significant stiffness, and high tensile strength. As a result, CNTs have been utilized as additives to enhance properties of various polymeric materials in a broad range of fields. In this study, we investigated the release of CNTs from CNT epoxy nanocomposites exposed to environmental weathering and mechanical stresses. The presence and amount of CNTs released from degraded polymer nanocomposites is important because CNTs can impact physiological systems in humans and environmental organisms. The weathering experiments in this study included nanocomposite exposure to both UV and a water spray, to simulate sunlight and rain exposure, whereas mechanical stresses were induced by shaking and ultrasonication. CNT release from epoxy nanocomposites was quantified by a 14C-labeling method that enabled measurement of the CNT release rates after different weathering and mechanical treatments. In this study, a sample oxidizer was used prior to liquid scintillation counting, because it was shown to reduce interferences from the presence of polymeric materials and achieve a high recovery (95%). Polymer nanocomposite degradation was confirmed by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and light microscopy. A continuous release of 14C-labeled nanomaterials was observed after each UV and simulated rain exposure period, with 0.23% (mass/mass) of the total embedded mass of CNTs being released from the CNT nanocomposite during the full weathering process, suggesting that the water spray induced sufficient mechanical stress to eliminate the protective effect of the surface agglomerated CNT network. Importantly, additional mechanical stresses imposed on the weathered nanocomposites by shaking and ultrasonication resulted in further release of approximately 0.27% (mass /mass).

Strong metal-support bonding enhanced thermal stability in Au-Al2O3 core-shell nanowires characterized by in situ transmission electron microscopy.

In this study, the thermal stability of Au-Al2O3 core-shell and Au nanowires was investigated by in situ scanning transmission electron microscopy and other techniques. The nanowires were synthesized by the helium droplets method and deposited on various substrates. The in situ characterization of Au-Al2O3 thermal stability demonstrated a substantially enhanced stability as compared to that of pure Au nanowires, which can be a transformative approach to design more durable Au-based nanocatalysts. Our study also revealed the existence of strong metal-support bonding in the Au/Al2O3 system.

Nitrogen removal mechanisms in biochar-amended sand filters treating onsite wastewater.

The performance of biochar-amended sand filters treating septic tank effluent (STE) was investigated in bench-scale columns. Softwood biochar showed higher NH4 + -N adsorption capacity (1.3 mg N g-1 ), and its water holding capacity (0.57 g ml-1 ) was significantly higher than sand (0.26 g ml-1 ). Two biochar amendment ratios (10% and 30%) were selected for STE treatment in short-term (20 days) and long-term (8 months) studies. During the short-term experiment, the overall total nitrogen removal efficiency was greater in biochar-amended sand columns (94.7%-95.6%) than in 100% sand columns (71.2%) due to the additional NH4 + -N adsorption by biochar. Greater nitrification performance was also observed in biochar-amended columns (87.1%-96.3%) than in 100% sand columns (61.4%) during long-term operation when alkalinity was insufficient. The nitrification performance in biochar-amended columns resumed more quickly (<7 days) after sufficient alkalinity was amended. The density of total biomass and nitrifying bacteria in biochar-amended columns (30%) were significantly higher at all experimental stages, suggesting biochar served as a growth media for enhanced biomass growth. The alkalinity changes and STE composition fluctuation had little impact on the nitrification performance of the 30% biochar-amended sand columns. In addition, biochar surface functional groups and zeta potential changed little after long-term STE filtration. Collectively, the results demonstrated proper biochar amendment ratio (30%) could enhance the nitrification performance of sand filters treating STE by increasing the system hydraulic retention time, providing additional alkalinity for nitrification, and serving as a growth media for enhanced biomass growth.

Assessment of physicochemical parameters and metal distribution in bog peat of the western segment of the North European part of Russia (Arkhangelsk region).

This article is devoted to the study of physicochemical parameters and the assessment of the accumulation and distribution of metals in peat deposits from the North European part of Russia (Arkhangelsk region). Peat profiles were selected both in the area with a high anthropogenic load and in a bog remote from industrial pollution. The determination of metals was carried out by using the methods X-ray fluorescence analysis and atomic absorption spectroscopy. It was determined that the studied bogs can be attributed to the low ash type, and the recorded pH and mineralisation values make it possible to attribute these deposits to the acid-oxidising facies of oligotrophic peatlands, characteristic of taiga landscapes. Assessment of metal accumulation showed a high content of titanium, chromium, lead, nickel, vanadium, cobalt, aluminium, silicon, and copper in peat, mainly caused by the burning of fossil fuels and industrial production, as well as the burning of urban and industrial waste. The peat profiles are characterised by significant fluctuations in the content of elements in different horizons. Studies have shown the need to monitor the content of metals in peatlands from the Arkhangelsk region to assess atmospheric pollution from industrial emissions, both at the moment and in the past.

Structural Ceramics Modified by Water Treatment Plant Sludge.

Water treatment plant (WTP) sludge is actively used in building materials production. The object of this research was modifying additives for ceramic bricks from WTP aluminium-containing sludge. The research aim of this study was to determine the suitability of a million-plus population city's WTP sludge as a burning-out additive in the production of structural ceramics and to establish the optimal conditions for obtaining products with the best characteristics. The raw water belongs to water belongs to the hydrocarbonate class, the calcium group, and it is of low turbidity (1.5-40 mg/L kaolin). Sludge, sourced from WTP sedimentation tanks, was dewatered by adding lime or by using the freezing-thawing method. The spray-dried WTP sludge is introduced into the clay in amounts of 5% to 20% by weight. The addition of 20% reduces the sensitivity of the clay to drying, reduces the density of ceramic by 20% and simultaneously increases its compressive strength from 7.0 to 10.2 MPa. The use of WTP sludge as a modifying additive, pretreated by the freezing-thawing method, makes it possible to obtain ceramic bricks with improved properties. The results can be used for WTP sludge containing aluminium obtained by treating water of medium turbidity and medium colour.

Direct Observation of Defect-Aided Structural Evolution in a Nickel-Rich Layered Cathode.

Ni-rich LiNi1-x-y Mnx Coy O2 (NMC) layered compounds are the dominant cathode for lithium ion batteries. The role of crystallographic defects on structure evolution and performance degradation during electrochemical cycling is not yet fully understood. Here, we investigated the structural evolution of a Ni-rich NMC cathode in a solid-state cell by in situ transmission electron microscopy. Antiphase boundary (APB) and twin boundary (TB) separating layered phases played an important role on phase change. Upon Li depletion, the APB extended across the layered structure, while Li/transition metal (TM) ion mixing in the layered phases was detected to induce the rock-salt phase formation along the coherent TB. According to DFT calculations, Li/TM mixing and phase transition were aided by the low diffusion barriers of TM ions at planar defects. This work reveals the dynamical scenario of secondary phase evolution, helping unveil the origin of performance fading in Ni-rich NMC.

Generalized Synthetic Strategy for Transition-Metal-Doped Brookite-Phase TiO2 Nanorods.

We report a generalized wet-chemical methodology for the synthesis of transition-metal (M)-doped brookite-phase TiO2 nanorods (NRs) with unprecedented wide-range tunability in dopant composition (M = V, Cr, Mn, Fe, Co, Ni, Cu, Mo, etc.). These quadrangular NRs can selectively expose {210} surface facets, which is induced by their strong affinity for oleylamine stabilizer. This structure is well preserved with variable dopant compositions and concentrations, leading to a diverse library of TiO2 NRs wherein the dopants in single-atom form are homogeneously distributed in a brookite-phase solid lattice. This synthetic method allows tuning of dopant-dependent properties of TiO2 nanomaterials for new opportunities in catalysis applications.

New aspects of improving the performance of WO3 thin films for photoelectrochemical water splitting by tuning the ultrathin depletion region.

In this work, we explored a facile, scalable and effective method for substantially enhancing photocurrent and incident-photon-to-current efficiency of WO3 thin-film photoanodes by a mild reduction treatment under low oxygen pressure. Experimental data from photoelectrochemical and electrochemical impedance spectroscopies have shown that such treatment can increase the charge carrier density on WO3 photoanode surfaces resulting in improvements in hole collection efficiency and reduction in charge recombination. Despite a much thinner layer of WO3 (about 500 nm) compared to those in other published studies, the electrodes exhibited an ultra-high photocurrent density of 1.81 mA cm-2 at 1.23 V vs. RHE. This current density is one of the highest ones among WO3-based photoanodes described in literature. The proposed surface modulation approach offers an effective and scalable method to prepare high-performance thin film photoanodes for photoelectrochemical water splitting.

Unexpected visible light driven photocatalytic activity without cocatalysts and sacrificial reagents from a (GaN)1-x (ZnO) x solid solution synthesized at high pressure over the entire composition range.

Optical and photocatalytic properties were determined for the solid solution series (GaN)1-x (ZnO) x synthesized at high pressure over the entire compositional range (x = 0.07 to 0.9). We report for the first time photocatalytic H2 evolution activity from water for (GaN)1-x (ZnO) x without cocatalysts, pH modifiers and sacrificial reagents. Syntheses were carried out by reacting GaN and ZnO in appropriate amounts at temperatures ranging from 1150 to 1200 °C, and at a pressure of 1 GPa. ZnGa2O4 was observed as a second phase, with the amount decreasing from 12.8 wt% at x = 0.07 to ∼0.5 wt% at x = 0.9. The smallest band gap of 2.65 eV and the largest average photocatalytic H2 evolution rate of 2.31 µmol h-1 were observed at x = 0.51. Samples with x = 0.07, 0.24 and 0.76 have band gaps of 2.89 eV, 2.78 eV and 2.83 eV, and average hydrogen evolution rates of 1.8 µmol h-1, 0.55 µmol h-1 and 0.48 µmol h-1, respectively. The sample with x = 0.9 has a band gap of 2.82 eV, but did not evolve hydrogen. An extended photocatalytic test showed considerable reduction of activity over 20 hours.

A comprehensive study of catalytic, morphological and electronic properties of ligand-protected gold nanoclusters using XPS, STM, XAFS, and TPD techniques.

Ultra-small gold nanoclusters were synthesized via a ligand exchange method and deposited onto different TiO2 supports to study their properties. STM imaging revealed that the as-synthesized gold nanoclusters had 2-D morphology consisting of monolayers of gold atoms. Subsequent XPS, XAFS, and CO oxidation TPD results indicated that heat treatments of gold clusters at different temperatures significantly altered their electronic and catalytic properties due to ligand deprotection and cluster agglomeration.

Strain Coupling of Conversion-type Fe3 O4 Thin Films for Lithium Ion Batteries.

Lithiation/delithiation induces significant stresses and strains into the electrodes for lithium ion batteries, which can severely degrade their cycling performance. Moreover, this electrochemically induced strain can interact with the local strain existing at solid-solid interfaces. It is not clear how this interaction affects the lithiation mechanism. The effect of this coupling on the lithiation kinetics in epitaxial Fe3 O4 thin film on a Nb-doped SrTiO3 substrate is investigated. In situ and ex situ transmission electron microscopy (TEM) results show that the lithiation is suppressed by the compressive interfacial strain. At the interface between the film and substrate, the existence of Lix Fe3 O4 rock-salt phase during lithiation consequently restrains the film from delamination. 2D phase-field simulation verifies the effect of strain. This work provides critical insights of understanding the solid-solid interfaces of conversion-type electrodes.

Metabolically healthy obese and metabolically unhealthy non-obese phenotypes in a Russian population.

INTRODUCTION: The aim of the study was to estimate the prevalence of metabolically healthy obese (MHO) and metabolically unhealthy non-obese (MUNO) phenotypes in Russian population. DESIGN AND METHODS: In cross-sectional epidemiology survey "Epidemiology of cardiovascular diseases and its risk factors in some regions of the Russian Federation" a random sampling of 21,121 subjects (25-65 years), stratified by age and sex was involved. Anthropometry, blood pressure (BP) measurement and fasting blood-tests (glucose, lipids) were performed according to standard protocols. Criteria for MHO-body mass index (BMI) ≥30 kg/m2 and ≤2 of markers: HDL < 1.30 (females)/1.04 (males) mmol/l; triglycerides ≥1.7 mmol/l; glucose ≥5.6 mmol/l or treatment; waist >88 (females)/102 (males) cm and BP ≥ 130/85 mm Hg or therapy. Criteria for MUNO was BMI < 30 kg/m2 and ≥2 markers listed above. Simple tabulations, descriptive statistics, post-stratification weights and logistic regression were used for analyses. RESULTS: MHO phenotype was detected in 2856 (41.5%) obese people; MUNO phenotype-in 4762 (34.4%) non-obese subjects. Aging was negatively associated with MHO and positively with MUNO prevalence. Gender was registered as determinant only of MUNO probability. No dramatic differences in lifestyle risk factors between 3 BMI groups (lean, overweight, obese) were found out. CONCLUSION: Half of obese Russian inhabitants are metabolically healthy. At the same time, metabolic abnormalities were detected in one third of non-obese participants with a shift to male gender.

Photoelectrochemical water splitting with a SrTiO3:Nb/SrTiO3 n+-n homojunction structure.

A very limited knowledge exists about the effect of non-uniform doping of epitaxially grown strontium titanate thin film electrodes on their photoelectrochemical performance in water splitting. In this work, water splitting photoanodes featuring an n+-n homojunction were fabricated by the pulsed laser deposition technique, where epitaxial SrTiO3 thin films were grown on Nb doped n+-SrTiO3 single crystalline substrates. Thermal diffusion of niobium from doped substrates into the deposited thin films formed an n+-n homojunction, which was profiled by angle-resolved XPS and cross-sectional STEM-EDX techniques. This homojunction was found to make a significant impact on the incident photon-to-current efficiency of photoanodes by affecting their depletion width, which was in agreement with the theoretical simulations.

Development of a New Generation of Stable, Tunable, and Catalytically Active Nanoparticles Produced by the Helium Nanodroplet Deposition Method.

Nanoparticles (NPs) are revolutionizing many areas of science and technology, often delivering unprecedented improvements to properties of the conventional materials. However, despite important advances in NPs synthesis and applications, numerous challenges still remain. Development of alternative synthetic method capable of producing very uniform, extremely clean and very stable NPs is urgently needed. If successful, such method can potentially transform several areas of nanoscience, including environmental and energy related catalysis. Here we present the first experimental demonstration of catalytically active NPs synthesis achieved by the helium nanodroplet isolation method. This alternative method of NPs fabrication and deposition produces narrowly distributed, clean, and remarkably stable NPs. The fabrication is achieved inside ultralow temperature, superfluid helium nanodroplets, which can be subsequently deposited onto any substrate. This technique is universal enough to be applied to nearly any element, while achieving high deposition rates for single element as well as composite core-shell NPs.

Understanding the Interactions of CO2 with Doped and Undoped SrTiO3.

SrTiO3 and doped SrTiO3 have a wide range of applications in different fields. For example, Rh-doped SrTiO3 has been shown to have photocatalytic activity for both hydrogen production and CO2 conversion. In this study, both undoped and Rh-doped SrTiO3 were synthesized by hydrothermal and polymerizable complex methods. Different characterizations techniques including X-ray photoelectron spectroscopy (XPS), XRD, Raman, and UV/Vis spectroscopy were utilized to establish correlations between the preparation methods and the electronic/structural properties of Rh-doped SrTiO3 . The presence of dopants and oxygen vacancies substantially influenced the CO2 interactions with the surface, as revealed by the in situ infrared spectroscopic study. The presence of distinctly different adsorption sites was correlated to oxygen vacancies and oxidation states of Ti and Rh.

The role of the domain size and titanium dopant in nanocrystalline hematite thin films for water photolysis.

Here we develop a novel technique for preparing high quality Ti-doped hematite thin films for photoelectrochemical (PEC) water splitting, through sputtering deposition of metallic iron films from an iron target embedded with titanium (dopants) pellets, followed by a thermal oxidation step that turns the metal films into doped hematite. It is found that the hematite domain size can be tuned from ∼10 nm to over 100 nm by adjusting the sputtering atmosphere from more oxidative to mostly inert. The better crystallinity at a larger domain size ensures excellent PEC water splitting performance, leading to record high photocurrent from pure planar hematite thin films on FTO substrates. Titanium doping further enhances the PEC performance of hematite photoanodes. The photocurrent is improved by 50%, with a titanium dopant concentration as low as 0.5 atom%. It is also found that the role of the titanium dopant in improving the PEC performance is not apparently related to the films' electrical conductivity which had been widely believed, but is more likely due to the passivation of surface defects by the titanium dopants.

Siege of Leningrad Survivors Phenotyping and Biospecimen Collection.

BACKGROUND: Poor nutrition during the early stages of human development can lead to rare pathological conditions in adult life. The best-known and most severe historical cases of famine include the Dutch 'Hunger Winter,' the Finnish famine, the Chinese Great famine, and the siege of Leningrad. The siege of Leningrad (now Saint Petersburg) was one of the longest in history, lasting 872 days, from September 8, 1941 to January 27, 1944. There were 670,000 registered deaths of the civil population, in which 97% died due to starvation. The aim of the present study is to create a collection of biospecimens from extensively phenotyped siege of Leningrad survivors, who underwent starvation during the early periods of their lives, and from a matched control group. METHODS: A total 305 siege survivors and 51 age- and sex- matched control subjects were investigated in of an observational retroprospective cohort study in 2009-2011 at a baseline visit. After 3 years of follow-up, 252 siege survivors (182 females and 70 males; mean age 74.7 ± 2.6 years) and 45 controls (32 females and 13 males; mean age 75.5 ± 2.8 years) were examined. All siege survivors were exposed to the extreme dietary restriction and stress associated with the siege in their early childhood. All participants signed informed consent and were subject to questionnaires and physical examination, as well as various laboratory and instrumental tests. Anthropometry, blood measurement, cognitive and physiological testing, and vascular damage assessment were performed. RESULTS: Blood specimens of the extensively phenotyped siege survivors were collected and processed (blood plasma, blood serum, and flash-frozen PBMC); serum and urine were used for laboratory tests. CONCLUSIONS: We believe that data obtained from this unique collection of biospecimens can elucidate the mechanisms of healthy aging and emphasize the importance of reproductive health, counseling, and monitoring among people with eating disorders.

Development of a conceptual framework for evaluation of nanomaterials release from nanocomposites: environmental and toxicological implications.

Despite the fact that nanomaterials are considered potentially hazardous in a freely dispersed form, they are often considered safe when encapsulated into a polymer matrix. However, systematic research to confirm the abovementioned paradigm is lacking. Our data indicates that there are possible mechanisms of nanomaterial release from nanocomposites due to exposure to environmental conditions, especially UV radiation. The degradation of the polymer matrix and potential release of nanomaterials depend on the nature of the nanofillers and the polymer matrix, as well as on the nature of environmental exposure, such as the combination of UV, moisture, mechanical stress and other factors. To the best of our knowledge there is no systematic study that addresses all these effects. We present here an initial study of the stability of nanocomposites exposed to environmental conditions, where carbon nanotube (CNT) containing polymer composites were evaluated with various spectroscopic and microscopic techniques. This work discusses various degradation mechanisms of CNT polymer nanocomposites, including such factors as UV, moisture and mechanical damage. An in vivo ingestion study with Drosophila showed reduced survivorship at each dose tested with free amine-functionalized CNTs, while there was no toxicity when these CNTs were embedded in epoxy. In addition to developing new paradigms in terms of safety of nanocomposites, the outcomes of this research can lead to recommendations on safer design strategies for the next generation of CNT-containing products.

Feasibility of congestive heart failure telemanagement using a wii-based telecare platform.

A gaming platform has been used to implement a Home Automated Telemanagement (HAT) system for chronic disease management in the patient's home. The system questions patients with congestive heart failure (CHF) to monitor symptoms, weight changes, and quality of life while educating the patient on their disease. The system is designed to run on the Nintendo Wii videogame console using an active internet connection and the console's built in internet browser. It questions the patient daily on their condition, monitors their weight, and provides the patient with instant feedback on their condition in the form of a 3 zone CHF action plan. The system is designed to be as simple as possible, making it usable by patients with no prior computer or videogame experience. This telemanagement system has been successfully designed and implemented to optimize the care of patients with CHF.

Subharmonic phase clusters in the complex Ginzburg-Landau equation with nonlinear global coupling.

A wide variety of subharmonic n -phase cluster patterns was observed in experiments with spatially extended chemical and electrochemical oscillators. These patterns cannot be captured with a phase model. We demonstrate that the introduction of a nonlinear global coupling (NGC) in the complex Ginzburg-Landau equation has subharmonic cluster pattern solutions in wide parameter ranges. The NGC introduces a conservation law for the oscillatory state of the homogeneous mode, which describes the strong oscillations of the mean field in the experiments. We show that the NGC causes a pronounced 2:1 self-resonance on any spatial inhomogeneity, leading to two-phase subharmonic clustering, as well as additional higher resonances. Nonequilibrium Ising-Bloch transitions occur as the coupling strength is varied.