Search

Prussian blue analogue nanocrystals of the CsINiII[CrIII(CN)6] cubic network with 6 nm size were assembled as a single monolayer on highly organized pyrolytic graphite (HOPG). X-ray magnetic circular dichroism (XMCD) studies, at the Ni and Cr L2,3 edges, reveal the presence of an easy plane of magnetization evidenced by an opening of the magnetic hysteresis loop (coercive field of ≈200 Oe) when the magnetic field, B, is at 60° relative to the normal to the substrate. The angular dependence of the X-ray natural linear dichroism (XNLD) reveals both an orientation of the nanocrystals on the substrate and an anisotropy of the electronic cloud of the NiII and CrIII coordination sphere species belonging to the nanocrystals' surface. Ligand field multiplet (LFM) calculations that reproduce the experimental data are consistent with an elongated tetragonal distortion of surface NiII coordination sphere responsible for the magnetic behavior of monolayer.

Perforated materials in the traditional sense are rigid, usually dense, costly and inflexible. For this study, polyester/cotton blended woven fabric as the base fabric, nano-SiO2 (silicon dioxide) as the functional particles and PU (polyurethane) as the matrix were selected. Accordingly, flexible PU/SiO2 perforated coating composites with different process parameters were developed. The influence of the nano-SiO2 content, perforation diameter, perforation rate, number of fiber felt layers and cavity depth on the sound absorption coefficient were investigated. The resonant frequencies of materials with different cavity depths were evaluated by both theoretical calculation and experimental method. It was found that the flexible perforated composite has good sound absorption and mechanical properties, and has great potential for applications requiring soft and lightweight sound absorption materials.

Increasing seawater exposure is causing mortality of coastal forests, yet the physiological response associated with seawater-induced tree mortality, particularly in non-halophytes, is poorly understood. We investigated the shifts in carbon and nitrogen (N) metabolism of mature Sitka-spruce trees that were dying after an ecosystem-scale manipulation of tidal seawater exposure. Soil porewater salinity and foliar ion concentrations increased after seawater exposure and were strongly correlated with the percentage of live foliated crown (PLFC; e.g., crown ‘greenness’, a measure of progression to death). Co-occurring with decreasing PLFC was decreasing photosynthetic capacity, N-investment into photosynthesis, N-resorption efficiency and non-structural carbohydrate (soluble sugars and starch) concentrations, with the starch reserves depleted to near zero when PLFC dropped below 5%. Combined with declining PLFC, these changes subsequently decreased total carbon gain and thus exacerbated the carbon starvation process. This study suggests that an impairment in carbon and N metabolism during the mortality process after seawater exposure is associated with the process of carbon starvation, and provides critical knowledge necessary to predict sea-level rise impacts on coastal forests.

Urolithiasis has become more prevalent throughout China.Knowing stone composition helps identify their possible underlying etiology of urolithiasis, provide appropriate individualized treatment and prevent stone recurrence.To explore characteristics of urinary stone composition in China, and determine the effects of gender, age, body mass index (BMI), stone localization and geographical region on stone composition.We used Fourier transform infrared spectroscopy to analyse urinary stones from consecutive patients at 46 hospitals in seven geographic areas of China between June 1, 2010 and May 31, 2015.Chi-squared tests and logistic regression analyses were performed to determine associations between stone composition and sex, age, body mass index (BMI), stone location, and geographic region.The most common stone components were calcium oxalate (CaOx; 65.9%), carbapatite (15.6%), urate (12.4%), struvite (2.7%), brushite (1.7%), and cystine (0.9%). CaOx and urate occurred more frequently in males, whereas carbapatite and struvite were more common in females (p

AIM: Increased atmospheric nitrogen deposition may have profound effects on tree carbon allocation dynamics. However, a comprehensive understanding of how nitrogen (N) enrichment influences carbon (C) allocation across plant functional processes and tree organs in individual trees remains elusive. LOCATION: Global forest ecosystems. TIME PERIOD: 1990–2018. MAJOR TAXA STUDIED: Trees. METHODS: We compiled data from 75 N addition experiments and conducted a meta‐analysis to evaluate the responses of C source (photosynthesis), sinks (growth and respiration) and storage (non‐structural carbohydrate concentrations) in different tree organs (foliage, above‐ground wood and roots) to N enrichment. RESULTS: N enrichment significantly enhanced C supply via photosynthesis (+39.6%, n = 128). C allocation to growth (biomass increment/production) significantly increased in foliage (+15.9%, n = 68) and above‐ground wood (+31.8%, n = 64; bole, branch, stem and/or twig) with increasing N availability, but not in roots, whereas allocation increased in roots via increasing fine root turnover rate (+22.6%, n = 11). N fertilization significantly increased C allocation to respiration in above‐ground wood (+46.6%, n = 12) and roots (+5.5%, n = 57), but not in foliage. N addition decreased non‐structural carbohydrate (NSC) concentrations in foliage (−5.4%, n = 16) and roots (−5.0%, n = 21), but increased NSC in above‐ground wood (+6.1%, n = 22). In addition, N enrichment effects were strongly affected by moderator variables. MAIN CONCLUSIONS: Our results demonstrate that N addition increased C allocation to growth and respiration more strongly than C allocation to NSC storage, and increased C allocation to above‐ground parts more strongly than to below‐ground parts. Our results are useful for better understanding the response of tree functional processes at organ level to N enrichment. The existing data also reveal that more long‐term experimental studies on mature trees in tropical and boreal forests are urgently needed to provide a basis for forecasting tree responses to N enrichment at the global scale.

Droplets of n-hexadecane were observed to shrink under ultraviolet (365 nm) and spread under blue light (475 nm) irradiation on an aqueous solution of photosensitive surfactant AzoTAB. We demonstrate that the change of wettability of n-hexadecane droplet on the solution depends on the change of oil-water interface tension. According to the addition of ethanol into the substrate, the change of relative diameter ΔD/D exceeds 20%, much larger than the system without ethanol. With light-emitting diode (LED) light as a sole power source, without any other triggers, we provide a contactless and isothermal method to realize photocontrolled alternative spreading and shrinking of a droplet on a liquid surface, which provides a basis for a chromocapillary-based optical zoom liquid lens.

An annular reactor for direct autothermal reforming of methane was proposed and studied numerically. A one-dimensional heterogeneous model was developed. The effects of feed inlet temperature, initial bed temperature and reactor length were investigated systematically to elucidate the autothermal boundary conditions. Simulation results indicate overall autothermal operation can be achieved if the reactor length exceeds 0.05 m and can be sustained with feed inlet velocity in the range from 0.2 to 5.0 m s−1. Simulation results reveal autothermacity can be kept with air-to-methane ratio of 1.0, which is lower than the theoretical value of 1.5. This is caused by the fact that most of consumed methane was oxidized only. Moreover, drastic bed temperature oscillation was observed in the start-up, which results from the mutual heat transfer between shell and tube in a small range and can be dampened by prolonging reactor length.

MnFe2O4 was a magnetic material that can be used to adsorb contaminants in the wastewater. Fe(II) could act as a reductant to transfer Cr(VI) into Cr(III). In this paper, mesoporous MnFe2O4 prepared by the coprecipitation method was incorporated with Fe(II) to remove Cr(VI). The samples before and after reaction were characterized by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. A total of 98~100% of Cr(VI) in solution was removed by MnFe2O4/Fe(II) hybrid system within a wide pH range (pH 3.0–9.0), which is due to the synergetic effects of adsorption from MnFe2O4 and reduction from Fe(II). Cr(VI) was reduced to Cr(III) by ≡Mn(II) on MnFe2O4 and Fe(II). Cr(III) and Fe(III) produced during reaction formed Cr(III)–Fe(III) hydroxides/oxyhydroxides and deposited on MnFe2O4. The inhibiting action of phosphate on the removal of Cr(VI) was greater than that of sulfate. Cr(VI) removal rate retained 94.5% at the fourth recycle test, which showed excellent re-usability of MnFe2O4.

Glucose is one of the major energy sources in organisms, which also is an important biomarker in clinic diabetes diagnosis. Owing to urgent requirements in clinic diabetes diagnosis, developing glucose detection method with accuracy, sensitivity and stability becomes urgently important. A sensitively and stably photoelectrochemical (PEC) non-enzymatic glucose sensor was constructed using the graphitic carbon nitride/α-Fe2O3 (g-CN/α-Fe2O3) heterojunction. The g-CN/α-Fe2O3 heterojunction was synthesized using a facile hydrothermal process in the presence of ionic liquids. The α-Fe2O3 nanoparticles anchored to the surface of g-CN, which contributed to forming formation the heterojunction between α-Fe2O3 and g-CN. The heterojunction can accelerate the migration of photogenerated carriers, resulting in enhanced PEC performance. As a result, the g-CN/α-Fe2O3 heterojunction achieved the enhancing photocurrent density compared to α-Fe2O3 alone. In addition, the introduction of glucose can boost electron-hole separation, resulting in sensitive PEC tracing of glucose level in aqueous solution. The sensor can trace the contents of glucose among 0.1 to 11.5 mg L−1 with an acceptable stability. Furthermore, the detection limit of the PEC non-enzymatic glucose sensor is significantly lowered to 0.03 mg L−1. It means the PEC non-enzymatic glucose sensor constructed by the g-CN/α-Fe2O3 heterojunction can be a promising platform to detect glucose.

In this paper, a novel Fe-Mn binary oxide-diatomite (FMBO-Dt) composite was prepared by co-precipitation method. The morphological and structural features of the synthesized composite were characterized by X-ray diffraction, Scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The catalytic activity of FMBO-Dt composite was investigated by the degradation of methylene blue (MB) in the presence of H2O2 and the effects of various factors such as Fe/Mn molar ratio, initial pH, and initial H2O2 concentration on MB degradation were evaluated. It was found that FMBO-Dt composite was highly effective for the degradation of MB in the presence of H2O2. In addition, the stability and reusability of the composite was also investigated. Finally, the possible mechanism for the decolorization of MB in the heterogeneous system was proposed. These results suggested that FMBO-Dt composite was a promising candidate for dye wastewater treatment.

Preparing organic coatings in a very controlled manner through the spreading of organic molecules on the water surface is one of the emphases for research in Langmuir-Blodgett (LB) technology. For preparing a homogeneous film and improving the quality of the film, it is our concern to have a deeper understanding of the dynamic process involved in spreading. Here, we present an overview of the hydrodynamic process under the influence of assisting the spreading solvent, which mainly focuses on the mechanical mechanisms of related phenomena. A typical spreading experiment of two-component mixed droplets on water substrate for the purpose of preparing LB films was carried out in this research. We perform the spreading of a liquid of silicone oil and oleic acid mixture on the horizontal surface of another immiscible deep water substrate, where the volatile silicone oil is the assisting spreading solvent with low viscosity. We find that it needs to exceed a certain critical value (60% in our experiment) to achieve a uniform and centrosymmetric spreading process, which is a key factor for getting a homogeneous film. We observe that the evolution of a large droplet into liquid film and then into small droplets under the action of surface tension gradient in experiments. Gravity-viscous and surface tension-viscous dominate successively in the whole spreading process, with its spreading radius r(t) ∝ t1/4 and r(t) ∝ t3/4, respectively. However, we also obtain singular values of scaling exponents -0.033 and -0.180, which is attributed to nonuniform distribution of the Laplace pressure caused by different curvatures near the capillary wave.

Atmospheric nitrogen (N) deposition has been observed to impact plant structure and functional traits in terrestrial ecosystems. Although the effect of N deposition on plant water use has been well-evaluated in laboratories and in experimental forests, the linkages between water and carbon relations under N deposition are unclear. Here, we report on hydraulics, gas exchange and carbon reserves of two broad-leaved tree species (Quercus mongolica and Fraxinus mandshurica) in mature temperate forests after a seven-year experiment with different levels of N addition (control (CK), low (23 kg N ha−1 yr−1), medium (46 kg N ha−1 yr−1) and high (69 kg N ha−1 yr−1)). We investigated variation in hydraulic traits (xylem-specific hydraulic conductivity (Ks), native percentage loss of conductivity (PLC) and leaf water potential), xylem anatomy (vessel diameter and density), gas exchange (maximum net photosynthesis rate and stomatal conductance) and carbon reserves (soluble sugars, starch and total nonstructural carbohydrates (NSC)) with different N addition levels. We found that medium N addition significantly increased Ks and vessel diameter compared to control, but accompanied increasing PLC and decreasing leaf water potential, suggesting that N addition results in a greater hydraulic efficiency and higher risk of embolism. N addition promoted photosynthetic capacity via increasing foliar N concentration but did not change stomatal conductance. In addition, we found increase in foliar soluble sugar concentration and decrease in starch concentration with N addition, and positive correlations between hydraulic traits (vessel diameter and PLC) and soluble sugars. These coupled responses of tree hydraulics and carbon metabolism are consistent with a regulatory role of carbohydrates in maintaining hydraulic integrity. Our study provides an important insight into the relationship of plant water transport and carbon dynamics under increasing N deposition.

Copper-doped manganese oxide nanorod catalysts with various Cu/Mn molar ratios have been prepared for catalytic combustion of Volatile organic compounds (VOCs). The effects of Cu/Mn ratio and calcination temperatures on catalytic performance were investigated. It turned out that the Cu1Mn1-500 sample exhibited the best catalytic combustion performance, to remove toluene at a temperature of 214 °C over 120 h without a significant decrease in toluene conversion. XRD, SEM, HRTEM, XPS were carried out to explore the physicochemical properties of catalysts, and the results demonstrated that doping copper into manganese oxides can contribute to rich oxygen vacancies, high redox capability, and hence increase the catalytic activity. In addition, both the large surface area and high crystallization of the obtained nanorod catalysts are also helpful for the high activity and stability of these copper-manganese mixed metal oxide catalysts. Furthermore, the presence of water vapor had little inhibition effect on the catalytic activity under the reaction condition.

Due to the toxicity and carcinogenicity, antimony and its compounds have been included as priority pollutants by Environmental Protection Agency of the United States (USEPA) and the European Union (EU). The removal methods of antimony need to be further studied. In this study, nZVI/Fe3O4 nanocomposites were synthesized, characterized, and applied to remove Sb(III). The nZVI/Fe3O4 nanocomposites before and after reaction with Sb(III) were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), vibrating sample magnetometry (VSM), and X-ray photoelectron spectroscopy (XPS). nZVI/Fe3O4 nanocomposites have a maximum Sb(III) adsorption capacity of 87.6 mg/g at pH 7.0. The removal of Sb(III) was a complex process including surface adsorption and oxidation. The removal of Sb(III) mainly involved three processes: (1) most Sb(III) was adsorbed on the surface of nZVI/Fe3O4 nanocomposites; (2) part of Sb(III) was rapidly oxidized to less toxic Sb(V); and (3) the generated Sb(V) was further adsorbed on the surface of nZVI/Fe3O4 nanocomposites. The nZVI/Fe3O4 nanocomposites can be separated from solution with an external magnet. The high Sb(III) removal efficiency and rapid separability of nZVI/Fe3O4 nanocomposites exhibited the great potential for the removal of Sb(III) from wastewater.

Targeting the autophagy process is considered to be a promising new strategy for drug treatment of ovarian cancer. α-Tomatine, a steroidal alkaloid extracted, is mainly isolated from leaves, roots and immature green tomatoes. α-Tomatine has biological activities such as anticancer, antioxidative and anti-inflammatory. The study aimed to explore the effects of α-tomatine on proliferation, apoptosis and autophagy and the underlying mechanisms in ovarian cancer Skov3 cells. After treatment with different concentrations of α-tomatine (0, 0.75, 1 and 1.5 μM) in Skov3 cells for 24 h, proliferation was determined by the CCK-8 assay, and apoptosis was detected by flow cytometric analysis. Autophagy in cells was determined by the number of fluorescent spots using confocal fluorescence microscopy after mRFP-GFP-LC3 transfection. The relationship between autophagy and apoptosis was proved by Beclin-1 overexpression. The protein expression levels were tested by western blotting. The results demonstrated that α-tomatine effectively repressed proliferation, exerted a proapoptotic effect and inhibited early-stage autophagy in Skov3 cells in a dose- and time-dependent manner. Additionally, Beclin-1 overexpression significantly suppressed α-tomatine-treated apoptosis in Skov3 cells, indicating that α-tomatine inhibits autophagy to induce apoptosis. We also found α-tomatine inhibited the protein expression levels of PI3K/Akt/mTOR signaling pathway. However, the autophagy inhibition of α-tomatine could be reversed obviously by Beclin-1 overexpression. Taken together, α-tomatine inhibited autophagy through Beclin-1. Our study suggests that α-tomatine, as a novel early-stage autophagy inhibitor, might be a potential drug for further treatment of ovarian cancer by inhibiting proliferation and promoting apoptosis.

In this study, a facile water-soluble fluorescence sensor 2-((2-hydroxybenzylidene)-amino)-2-(hydroxymethyl)propane-1,3-diol (ST) was synthesized via one-step reaction, and its fluorescence sensing performance for Al3+ both in aqueous solution and on paper substrate was evaluated. The results showed that ST exhibited an specific fluorescence "turn-on" response to Al3+ over other cations in aqueous solution as well as on the test paper. The limit of detection was found to be 3.2×10-7M, which revealed that the obtained Schiff-base based fluorescence chemosensor ST possessed a great potential for the rapid, quantitative and qualitative detection of Al3+.

Sepsis is still a severe health problem worldwide with high morbidity and mortality. Blood bacterial culture remains the gold standard for the detection of pathogenic bacteria in bloodstream infections, but it is time-consuming, and both the sophisticated equipment and well-trained personnel are required. Immunoassays and genetic diagnosis are expensive and limited to specificity and sensitivity. Aptamers are single-stranded deoxyribonucleic acid (ssDNA) and ribonucleic acid (RNA) oligonucleotide or peptide sequence generated in vitro based on the binding affinity of aptamer-target by a process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX). By taking several advantages over monoclonal antibodies and other conventional small-molecule therapeutics, such as high specificity and affinity, negligible batch-to-batch variation, flexible modification and production, thermal stability, low immunogenicity and lack of toxicity, aptamers are presently becoming promising novel diagnostic and therapeutic agents. This review describes the prospective application of aptamerbased laboratory diagnostic assays and therapeutics for pathogenic bacteria and toxins in bloodstream infections.

This study aimed to screen DNA aptamers against the signal molecule C4-HSL of the rhl system for the inhibition of biofilm formation of Pseudomonas aeruginosa using an improved systematic evolution of ligand by exponential enrichment (SELEX) method based on a structure-switching fluorescent activating bead. The aptamers against the C4-HSL with a high affinity and specifity were successfully obtained and evaluated in real-time by this method. Results of biofilm inhibition experiments in vitro showed that the biofilm formation of P. aeruginosa was efficiently reduced to about 1/3 by the aptamers compared with that of the groups without the aptamers. Independent secondary structure simulation and computer-aided tertiary structure prediction (3dRNA) showed that the aptamers contained a highly conserved Y-shaped structural unit. Therefore, this study benefits the search for new methods for the detection and treatment of P. aeruginosa biofilm formation.

Non-structural carbohydrates (NSC) play a central role in plant functioning as energy carriers and building blocks for primary and secondary metabolism. Many studies have investigated how environmental and anthropogenic changes, like increasingly frequent and severe drought episodes, elevated CO2 and atmospheric nitrogen (N) deposition, influence NSC concentrations in individual trees. However, this wealth of data has not been analyzed yet to identify general trends using a common statistical framework. A thorough understanding of tree responses to global change is required for making realistic predictions of vegetation dynamics. Here we compiled data from 57 experimental studies on 71 tree species and conducted a meta-analysis to evaluate general responses of stored soluble sugars, starch and total NSC (soluble sugars + starch) concentrations in different tree organs (foliage, above-ground wood and roots) to drought, elevated CO2 and N deposition. We found that drought significantly decreased total NSC in roots (-17.3%), but not in foliage and above-ground woody tissues (bole, branch, stem and/or twig). Elevated CO2 significantly increased total NSC in foliage (+26.2%) and roots (+12.8%), but not in above-ground wood. By contrast, total NSC significantly decreased in roots (-17.9%), increased in above-ground wood (+6.1%), but was unaffected in foliage from N fertilization. In addition, the response of NSC to three global change drivers was strongly affected by tree taxonomic type, leaf habit, tree age and treatment intensity. Our results pave the way for a better understanding of general tree function responses to drought, elevated CO2 and N fertilization. The existing data also reveal that more long-term studies on mature trees that allow testing interactions between these factors are urgently needed to provide a basis for forecasting tree responses to environmental change at the global scale.

Coal liquefaction residues with a high content of nitrogen were used to prepare N-doped activated carbon as a catalyst of the oxygen reduction reaction (ORR). N-Doped activated carbon materials prepared at 900 °C (AC-900) exhibited a large specific surface area of 3130 m2 g−1 and a small average pore size of 1.91 nm. AC-900 also displayed more edges on the surface and higher N-doped contents of pyridinic-N and graphitic-N, which enhanced the conductivity and created more catalytic active sites. Electrochemical tests showed for AC-900 a half-peak current density of −2.11 mA cm−2 at a potential of −0.17 V, which was only 63 mV lower than that of the commercial Pt/C (20%) catalyst. As much as 85.1% of the initial current density for AC-900 was maintained during the course of a stability test lasting 20000 s compared with a value of 82.1% for the commercial Pt/C (20%) catalyst. Low-cost N-doped activated carbon should not only be an efficient non-precious catalyst for the ORR in alkaline fuel cells but also offer a porous carbon precursor for the further preparation of compound catalysts.

Microporous carbon material with a high surface area of 1562 m 2 /g is prepared via an impregnation method with NaY zeolite as hard template. The results indicate that glucose, an environmental friendly material, could be used as the carbon precursor of zeolite templated carbons, in comparison with the toxicity of furfuryl alcohol and lower surface area of carbons generated from sucrose. Effects of reactant molar ratios and carbonization conditions on the textural properties are addressed. Although higher carbonization temperature favors more complete carbonization reactions, it also causes the collapse of small pores and the formation of large pores at the same time. Further characterizations of the obtained carbon materials with XRD, SEM and N 2 adsorption–desorption measurements are presented. Methane adsorption tests on carbon materials are investigated with the static volumetric method at 300 K. The higher adsorption amount of 9.9 wt.% was achieved at 3.5 MPa on sample with a higher micropore volume, indicating that micropores were playing a crucial role for the methane storage process.

Atmospheric nitrogen (N) deposition has been found to significantly affect plant growth and physiological performance in terrestrial ecosystems. Many individual studies have investigated how N addition influences plant functional traits, however these investigations have usually been limited to a single species, and thereby do not allow derivation of general patterns or underlying mechanisms. We synthesized data from 56 papers and conducted a meta-analysis to assess the general responses of 15 variables related to leaf economics, gas exchange, and hydraulic traits to N addition among 61 woody plant species, primarily from temperate and subtropical regions. Results showed that under N addition, leaf area index (+10.3%), foliar N content (+7.3%), intrinsic water-use efficiency (+3.1%) and net photosynthetic rate (+16.1%) significantly increased, while specific leaf area, stomatal conductance, and transpiration rate did not change. For plant hydraulics, N addition significantly increased vessel diameter (+7.0%), hydraulic conductance in stems/shoots (+6.7%), and water potential corresponding to 50% loss of hydraulic conductivity (P50, +21.5%; i.e., P50 became less negative), while water potential in leaves (−6.7%) decreased (became more negative). N addition had little effect on vessel density, hydraulic conductance in leaves and roots, or water potential in stems/shoots. N addition had greater effects on gymnosperms than angiosperms and ammonium nitrate fertilization had larger effects than fertilization with urea, and high levels of N addition affected more traits than low levels. Our results demonstrate that N addition has coupled effects on both carbon and water dynamics of woody plants. Increased leaf N, likely fixed in photosynthetic enzymes and pigments leads to higher photosynthesis and water use efficiency, which may increase leaf growth, as reflected in LAI results. These changes appear to have downstream effects on hydraulic function through increases in vessel diameter, which leads to higher hydraulic conductance, but lower water potential and increased vulnerability to embolism. Overall, our results suggest that N addition will shift plant function along a tradeoff between C and hydraulic economies by enhancing C uptake while simultaneously increasing the risk of hydraulic dysfunction.

Porous carbons are important adsorbents for hydrogen. In this work mesoporous carbon material with ultrahigh surface area is prepared with hexagonally packed mesoporous silica (HMS) as template. After a systematic optimization of different synthesis parameters, carbon material with a specific surface area of 2644 m2/g is obtained with resol as carbon precursors, the highest value reported so far for silica-templated mesoporous carbons. The material can be loaded with nickel nanoparticles through addition of nickel chloride hexahydrate into the resol solution. Hydrogen uptake of the nickel-decorated carbon at room temperature and 20 bar reaches 2.66 mmol/g, 78% higher than that of the pristine carbon. Due to the sharp decrease of the specific surface area and pore volume after nickel decoration, the improvement is attributed to effects of nickel nanoparticles.

Aptamers are single-stranded deoxyribonucleic acid or ribonucleic acid oligonucleotides generated in vitro based on affinity for certain target molecules by a process known as Systematic Evolution of Ligands by Exponential Enrichment. Aptamers can bind their target molecules with high specificity and selectivity by means of structure compatibility, stacking of aromatic rings, electrostatic and van der Waals interactions, and hydrogen bonding. With several advantages over monoclonal antibodies and other conventional small-molecule therapeutics, such as high specificity and affinity, negligible batch to batch variation, flexible modification and stability, lack of toxicity and low immunogenicity, aptamers are becoming promising novel diagnostic and therapeutic agents. This review focuses on the development of aptamers as potential therapeutics for autoimmune diseases, including diabetes mellitus, multiple sclerosis, rheumatoid arthritis, myasthenia gravis, and systemic lupus erythematosus.

Global atmospheric nitrogen deposition has increased steadily since the 20th century, and has complex effects on terrestrial ecosystems. This work synthesized results from 54 papers and conducted a meta-analysis to evaluate the general response of 15 variables related to plant root traits to simulated nitrogen deposition. Simulated nitrogen deposition resulted in significantly decreasing fine root biomass (

Bi2WO6 modified with few-layer BN was synthesized by an impregnation method. The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), ultraviolet-visible diffuse reflection spectroscopy (DRS) and Fourier transform infrared spectroscopy (FT-IR). The as-prepared BN/Bi2WO6 photocatalysts exhibited a higher photocatalytic activity for the degradation of Rhodamine B (RhB) than the pure Bi2WO6. The 3 wt% BN/Bi2WO6 photocatalyst showed the best photocatalytic activity and high stability after five runs under visible light irradiation. The enhanced visible-light photocatalytic activity could be attributed to the synergetic effect of few-layer BN and Bi2WO6.

A water-soluble fluorescence sensor (SA) was facilely synthesized via a one-step condensation reaction between commercially available salicylaldehyde and 2-(2-aminoethylamino)ethanol with high yield. The addition of Zn2+ and Al3+ to SA showed drastic enhancements of the emission intensities at 458 nm and 376 nm, respectively, while exhibiting negligible interference in the presence of typical competitive ions such as Fe3+, Cr3+, Hg2+ and Cd2+. This phenomenon indicates that SA may be helpful for rapid, quantitative and qualitative detection of Zn2+ and Al3+.

The measurement of acoustic nonlinear response is known as a promising technique to characterize material micro-damages. In this paper, nonlinear ultrasonic approach is used to characterize the evolution of fatigue induced micro-cracks in polymer bonded explosives. The variations of acoustic nonlinearity with respect to fatigue cycles in the specimens are obtained in this investigation. The present results show a significant increase of acoustic nonlinearity with respect to fatigue cycles. The experimental observation of the correlation between the acoustic nonlinearity and fatigue cycles in carbon/epoxy laminates, verifies that an acoustic nonlinear response can be used to evaluate the progressive fatigue damage in the granular polymer bonded explosives. The sensitivity comparison of nonlinear and linear parameters of ultrasonic waves in the specimens shows that nonlinear acoustic parameters are more promising indicators to fatigue induced micro-damage than linear ones. The feasibility study of the micro-damage assessment of polymer bonded explosives by nonlinear ultrasonic technique in this work can be applied to damage identification, material degradation monitoring, and lifetime prediction of the explosive parts.

Trapped Rydberg ions are a promising new system for quantum information processing. They have the potential to join the precise quantum operations of trapped ions and the strong, long-range interactions between Rydberg atoms. Technically, the ion trap will need to stay active while exciting the ions into the Rydberg state, else the strong Coulomb repulsion will quickly push the ions apart. Thus, a thorough understanding of the trap effects on Rydberg ions is essential for future applications. Here we report the observation of two fundamental trap effects. First, we investigate the interaction of the Rydberg electron with the quadrupolar electric trapping field. This effect leads to Floquet sidebands in the spectroscopy of Rydberg D-states whereas Rydberg S-states are unaffected due to their symmetry. Second, we report on the modified trapping potential in the Rydberg state compared to the ground state which results from the strong polarizability of the Rydberg ion. We observe the resultant energy shifts as a line broadening which can be suppressed by cooling the ion to the motional ground state in the directions orthogonal to the excitation laser.

Aptamers are short DNA/RNA oligonucleotides selected by a process known as Systematic Evolution of Ligands by Exponential Enrichment (SELEX) based on affinity for target molecules. Since aptamers have several advantages over monoclonal antibodies, such as high specificity and affinity, flexible modification and stability, and lack of toxicity and immunogenicity, they are promising novel diagnostic and therapeutic agents. In this review, we will describe the development of aptamers against thrombin, von Willebrand factor (vWF), factor IX, and factor XII as potential anticoagulants or antithrombotics for cardiovascular diseases, especially those that have entered clinical trials.

Four different chiral diamino diethers synthesized from N-isopropyl valinol or N-isopropyl alaninol were lithiated with n-butyllithium in tetrahydrofuran or diethyl ether. Crystal structures of the dilithiated diamino diethers were determined by X-ray diffraction. Three dilithiated diamino diethers including (2S,2'S)-1,1'-(butane-1,4-diylbis(oxy))bis(N-isopropylpropan-2-amine) 7, (2S,2'S)-1,1'-(pentane-1,5-diylbis(oxy))bis(N-isopropylpropan-2-amine) 8, and (2S,2'S)-1,1'-(heptane-1,7-diylbis(oxy))bis(N-isopropyl-3-methylbutan-2-amine) 9 are dimers, whereas dilithiated (2S,2'S)-1,1'-(pentane-1,5-diylbis(oxy))bis(N-isopropyl-3-methylbutan-2-amine) 10 is a monomer. The lithium atoms in all crystal structures adopt a nonequivalent coordination protocol and exist in two different environments in which one of the lithium atoms is tetra-coordinated while the other one is tri-coordinated. The solution structures of the dilithiated diamino diethers are also characterized by a variety of NMR experiments including diffusion-ordered NMR spectroscopy (DOSY) with diffusion coefficient-formula (D-FW) weight correlation analyses and other one- and two-dimensional NMR techniques.

Ultrasonic guided wave techniques have been widely used for long range nondestructive detection in tube-like structures. The present paper investigates the ultrasonic linear and nonlinear parameters for evaluating the thermal damage in aluminum pipe. Specimens were subjected to thermal loading. Flexible polyvinylidene fluoride (PVDF) comb transducers were used to generate and receive the ultrasonic waves. The second harmonic wave generation technique was used to check the material nonlinearity change after different heat loadings. The conventional linear ultrasonic approach based on attenuation was also used to evaluate the thermal damages in specimens. The results show that the proposed experimental setup is viable to assess the thermal damage in an aluminum pipe. The ultrasonic nonlinear parameter is a promising candidate for the prediction of micro-damages in a tube-like structure.

Traditional spectroscopic analysis based on the Beer-Lambert law cannot analyze the analyte with high concentration and interference between different compositions, such as the electrolyte in vanadium redox flow batteries (VRBs). Here we propose a new method for online detection of such analytes. We demonstrate experimentally that, by comparing the transmittance spectrum of the analyte with the spectra in a preprepared database using our intensity-corrected correlation coefficient (ICCC) algorithm, parameters such as the state of charge (SOC) of both the positive and the negative electrolytes in the VRB can be online monitored. This method could monitor the level of the electrolytes imbalance in the VRB, which is useful for further rebalancing the electrolyte and restoring the capacity loss of the VRB. The method also has the potential to be used in the online detection of other chemical reactions, in which the chemical reagents have high concentration and interferences between different compositions.

A metastable, polymorphic hexameric crystal structure of lithium pinacolone enolate (LiOPin) is reported along with three preparation methods. NMR-based structural characterization implies that the lithium pinacolate hexamer deaggregates to a tetramer in toluene but retains mainly the hexameric structure in nonaromatic hydrocarbon solvents such as cyclohexane. Moreover, the presence of a small amount of lithium aldolate (LiOA) dramatically influences the aggregation state of LiOPin by forming a mixed aggregate with a 3:1 ratio (LiOPin3·LiOA).

In this paper, bismuth oxybromide (BiOBr) nanosquares photocatalysts were synthesized via a facile hydrothermal method with the double regulation of the ionic liquid (IL) 1-hexadecyl-3-methylimidazolium bromide and ammonium bismuth citrate (BCA). To the best of our knowledge, this report is the first to describe the BiOBr material with simultaneous bismuth and halogen bidirectional source regulation. The structures, components, morphologies, optical properties and photocatalytic properties of the as-prepared samples were specifically explored. The photocatalytic ability was assessed using the degradation of rhodamine B under visible light irradiation. The BiOBr-IL+BCA exhibited improved photocatalytic activity compared with the BiOBr materials without double regulation. The primary active species were determined to be holes (h+) and superoxide radicals (O2-) using electron spin resonance (ESR) analysis and free radical trapping experiments. This enhanced activity was attributed to its larger specific surface, the superior electron transfer ability, and the increased negative conduction band position, which favors the photogenerated electrons to trap the molecular oxygen to produce O2-. The production of more O2- can benefit the removal of pollutants.

A method is presented for monitoring the state of charge (SOC) of vanadium redox flow batteries (VRBs) by the transmission spectrum of the positive electrolyte [V(IV)/V(V)]. We use the transmission spectrum rather than the absorption spectrum for better signal noise ratio. In order to solve the complicated relations between the spectrum and the SOC of the VRB, the entire shape of the spectrum is utilized instead of the data at one wavelength. We experimentally demonstrate that SOCs from 0 to 100 % can be monitored by comparing the transmission spectra of the positive electrolytes [V(IV)/V(V)] with the database, which is previously built by detecting standard samples. The method has potential ability to monitor the level of imbalances of the VRB, which is important for rebalancing the electrolyte and restoring the capacity loss of a VRB.

Permanent electric dipole moments in molecules require a breaking of parity symmetry. Conventionally, this symmetry breaking relies on the presence of heteronuclear constituents. We report the observation of a permanent electric dipole moment in a homonuclear molecule in which the binding is based on asymmetric electronic excitation between the atoms. These exotic molecules consist of a ground-state rubidium (Rb) atom bound inside a second Rb atom electronically excited to a high-lying Rydberg state. Detailed calculations predict appreciable dipole moments on the order of 1 Debye, in excellent agreement with the observations.

Increasingly, the undergraduate chemistry curriculum includes nuclear magnetic resonance (NMR) spectroscopy. Advanced NMR techniques are often taught including two-dimensional gradient-based experiments. An investigation of intermolecular forces including viscosity, by a variety of methods, is often integrated in the undergraduate physical and organic laboratory curricula. An experiment is described that couples advanced NMR techniques with the investigation of viscosity, a physical property based on molecular structure.

The enhanced performance of the ozone-enhanced photocatalysis process (O 3 -PCO) on toluene destruction was evaluated and its mechanism was investigated. The toluene removal efficiency (TRE) and stability of O 3 -PCO was compared with that of conventional PCO. The gaseous intermediates of toluene oxidation in various processes were analyzed by GC–MS. The formation pathways of main oxidants and their role in toluene destruction were studied. Results indicated that the TRE of O 3 -PCO was 8 times higher than that of PCO because more oxidants were generated besides hydroxyl radicals (OH ). The generation rate and amount of OH was remarkably increased in the O 3 -PCO process which contained more pathways (such as UV/O 3 and O 3 /TiO 2 ) to produce OH besides UV/TiO 2 . The GC–MS results showed that the types and amounts of byproducts were dramatically reduced due to the formation of more oxidants and complete oxidation, leading to remarkable enhancement of the photocatalyst's durability in the O 3 -PCO process. Its mechanism was greatly different from the conventional PCO. Both OH and active oxygen (O ) played a key role in the O 3 -PCO process. Based on the intermediates and the main oxidants, possible pathways of toluene degradation were proposed.

The Au/CeO2 catalysts were synthesized by co-precipitation (CP), deposition-precipitation (DP) and metallic colloids deposition (MCD) method, and tested for oxidation of volatile organic compounds (VOCs). It was revealed that the Au/CeO2 catalyst prepared by DP method was the most efficient catalyst towards the total oxidation of toluene. The Au/CeO2 catalysts had obviously high catalytic activity, and the best results was obtained on 3 wt.% Au/CeO2 catalyst prepared by DP method. These catalysts were characterized by means of specific surface area (BET), atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). XRD data showed that only metallic Au phase existed in the catalysts, and the size of gold particles played a crucial role in the catalytic conversion of toluene. The catalytic activity of Au/CeO2 was related to the interaction between gold particles and supports, and the capability of gold particles to weaken the surface Ce-O bonds adjacent to Au atoms. This interaction enhanced the reactivity of the CeO2 surface capping oxygen which was involved in volatile organic compounds oxidation.

Biodiesel, fatty acid methyl esters derived from vegetable oils, is a well-established alternative to petroleum diesel. We have developed a rapid 1H diffusion-ordered nuclear magnetic resonance spectroscopy (DOSY NMR) method to resolve mixtures of mono-, di-, and triacyglycerols along with their methyl esters. Because of the differences in diffusion coefficients between the starting materials (triglycerides), intermediates (mono- and diglycerols), and products (methyl esters), we were able to accurately predict the formula weights of these species in solution. This technique was used to monitor transesterification reactions of virgin and waste vegetable oils. In addition to proving its utility to assess conversion of starting materials, we found that 1,3-diacylglycerol is the major intermediate formed during alkali-catalyzed biodiesel production.

Development and application of physically separated references for aqueous (1)H DOSY diffusion coefficient-formula weight (D-FW) correlation analysis is reported. Commercially available biological buffers (Tris and HEPES) and a water-soluble alcohol (tert-butanol) were used as physically separated references for a Ru and a Mn complex in D(2)O. This extension of DOSY D-FW analysis expands its applicability to a wide variety of water-soluble molecules or metal complexes, with particular application to green chemistry.

The development of (6)Li diffusion-ordered NMR spectroscopy (DOSY) is reported. This technique is applied to (6)Li organometallic complexes. (6)Li DOSY provides a facile means of identification of peaks in the (6)Li spectrum, as well as evidence of mixed aggregates based on relative diffusion coefficients. (6)Li data is correlated to (1)H diffusion experiments through (6)Li{(1)H} HOESY and/or (1)H{(6)Li} HMBC experiments to obtain formula weight information of Li aggregates.