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Transforming to biochar provides an environmentally friendly approach for crop residue reutilization, which are usually applied as sorbent for heavy metal removal. As typical silicon-rich material, the specific sorptive mechanisms of rice straw derived biochar (RSBC) are concerned, especially at the low concentration range which is more environmentally relevant. In the present study, Cd sorption onto RSBCs at the concentration of ≤ 5 mg/L was investigated. The sorptive capacity was positively correlated with the pyrolytic temperature of the biochar and the environmental pH value. Water soluble minerals of the RSBCs played the dominant roles in Cd sorption, contributing 29.2%, 62.5% and 82.9% of the total sorption for RSBCs derived under 300°C, 500°C and 700°C, respectively. Increased number of cations, dominantly K+, were exchanged during the sorption. Coprecipitation with cations and carbonates may also be contributive to the sorption. The dissolution of silicon-containing minerals was found to be declined during sorption, suggesting its involvement in the sorption process, possibly through precipitation. Whilst, the sparingly soluble silicate crystals may impose ignorable role in the sorption. Complexation with organic groups is only a minor mechanism in Cd sorption, compared to the much more dominant roles of the inorganic ashes.

A 2D cluster-based coordination polymer of {Fe5}-2D was developed by hierarchical dimension augmentation from its 1D coordination polymer of {Fe5}-1D and discrete 0D cluster of {Fe5}-0D. And a possible bottom-up synthesis mechanism was proposed.

The increasing demand for rare earth elements (REEs) motivates the development of novel strategies for cost-effective REE recovery from secondary sources, especially rare earth tailings. The biggest challenges in recovering REEs from ion-adsorption rare earth tailings are incomplete extraction of cerium (Ce) and the coleaching of iron (Fe) and manganese (Mn). Here, a synergistic process between reduction and stabilization was proposed by innovatively using elemental sulfur (S) as reductant for converting insoluble CeO2 into soluble Ce2(SO4)3 and transforming Fe and Mn oxides into inert FeFe2O4 and MnFe2O4 spinel minerals. After the calcination at 400 °C, 97.0% of Ce can be dissolved using a diluted sulfuric acid, along with only 3.67% of Fe and 23.3% of Mn leached out. Thermodynamic analysis reveals that CeO2 was indirectly reduced by the intermediates MnSO4 and FeS in the system. Density functional theory calculations indicated that Fe(II) and Mn(II) shared similar outer electron arrangements and coordination environments, favoring Mn(II) over Ce(III) as a replacement for Fe(II) in the FeO6 octahedral structure of FeFe2O4. Further investigation on the leaching process suggested that 0.5 mol L-1 H2SO4 is sufficient for the recovery of REEs (97.0%). This research provides a promising strategy to selectively recover REEs from mining tailings or secondary sources via controlling the mineral phase transformation.

Low-molecular-weight alkyl amines have attracted attention for their roles in new particle formation, ultrafine particle growth, and neutralizing aerosol acidity. The major source of the low-molecu...

DNA self-assembled nanostructures have been considered as effective vehicles for biomolecule delivery because of their excellent biocompatibility, cellular permeability, noncytotoxicity, and small size. Here, we report an efficient antiviral strategy with self-assembled tetrahedral framework nucleic acids (tFNAs) delivering small interfering RNA (t-siRNA) to silence classical swine fever virus (CSFV) gene in porcine host cells. In this study, two previously reported siRNAs, C3 and C6, specifically targeting the CSFV genome were selected and modified on tFNAs, respectively, and termed t-C3 and t-C6. Results indicate that t-C3 and t-C6 can inhibit the viral proliferation of CSFV in kidney derived porcine cells, PK-15, effectively and that inhibition was markedly stronger than free siRNA-C3 or siRNA-C6 only. In addition, the DNA nanostructure also has high cargo-carrying capacity, allowing to deliver multiple functional groups. To improve the antiviral ability of tFNAs, a dual-targeting DNA nanostructure t-C3-C6 was constructed and used to silence the CSFV gene in porcine host cells. This study found that t-C3-C6 can inhibit the viral release and replication, exhibiting outstanding anti-CSFV capabilities. Therefore, these dual-targeting tFNAs have great potential in virus therapy. This strategy not only provides a novel method to inhibit CSFV replication in porcine cells but also verifies that tFNAs are effective tools for delivery of antiviral elements, which have great application potential.

Nitrogen oxides (NOx) play a key role in regulating the oxidizing capacity of the atmosphere through controlling the abundance of O3, OH, and other important gas and particle species. Some recent studies have suggested that particulate nitrate, which is conventionally considered as the ultimate oxidation product of NOx, can undergo "renoxification" via photolysis, recycling NOx and HONO back to the gas phase. However, there are large discrepancies in estimates of the importance of this channel, with reported renoxification rate constants spanning three orders of magnitude. In addition, previous laboratory studies derived the rate constant using bulk particle samples collected on substrates instead of suspended particles. In this work, we study renoxification of suspended submicron particulate sodium and ammonium nitrate through controlled laboratory photolysis experiments using an environmental chamber. We find that, under atmospherically relevant wavelengths and relative humidities, particulate inorganic nitrate releases NOx and HONO less than 10 times as rapidly as gaseous nitric acid, putting our measurements on the low end of recently reported renoxification rate constants. To the extent that our laboratory conditions are representative of the real atmosphere, renoxification from the photolysis of inorganic particulate nitrate appears to play a limited role in contributing to the NOx and OH budgets in remote environments. These results are based on simplified model systems; future studies should investigate renoxification of more complex aerosol mixtures that represent a broader spectrum of aerosol properties to better constrain the photolysis of ambient aerosols.

Using the pyridine–triazole based ligand of bis(3-(pyridin-2-yl)-1,2,4-triazol-5-yl)methane (H2L), two hexanuclear dysprosium(III) complexes, [Dy6(μ4-NO3)2 (OAc)6(L)4(DMF)2]·2NO3 (1) and [Dy6(μ3-OH)4(μ2-OH)2(OAc)4(L)4(EtOH)4]·2H2O (2), have been successfully obtained by hydrothermal reaction in different solvents. The crystal structure analysis reveals that the {Dy6} core in 1 is connected by two μ4-NO3− ions, whereas by four μ3-OH− and two μ2-OH− ions in 2. The HRESI-MS (high-resolution electrospray ionization mass spectrum) measurement of 1–2 was recorded. The presence of prominent peaks for the {Dy6} fragment in 1 (m/z, 1354–1380) at different ion-source voltages showed the higher solution stability and structural integrity of the {Dy6} cluster in 1, compared with that in 2. Temperature- and frequency-dependent alternating current (AC) susceptibility measurements of 1–2 in a zero direct current field display only a characteristic feature of single-molecule magnet (SMM) behavior for 2, indicating different magnetic behavior.

Retinal degeneration (RD) refers to a group of blinding retinopathies leading to the progressive photoreceptor demise and vision loss. Treatments against this debilitating disease are urgently needed. Intraocular delivery of exosomes represents an innovative therapeutic strategy against RD. In this study, we aimed to determine whether the subretinal delivery of RPE-derived exosomes (RPE-Exos) can prevent the photoreceptor death in RD. RD was induced in C57BL6 mice by MNU administration. These MNU administered mice received a single subretinal injection of RPE-Exos. Two weeks later, the RPE-Exos induced effects were evaluated via functional, morphological, and behavior examinations. Subretinal delivery of RPE-Exos efficiently ameliorates the visual function impairments, and alleviated the structural damages in the retina of MNU administered mice. Moreover, RPE-Exos exert beneficial effects on the electrical response of the inner retinal circuits. Treatment with RPE-Exos suppressed the expression levels of inflammatory factors, and mitigated the oxidative damage, indicating that subretinal delivery of RPE-Exos constructed a cytoprotective microenvironment in the retina of MNU administered mice. Our data suggest that RPE-Exos have therapeutic effects against the visual impairments and photoreceptor death. These findings will enrich our knowledge of RPE-Exos, and highlight the discovery of a promising medication for RD.

While many studies have reported on the oxidation kinetics of ammonia and amines with the hydroxyl radical (OH) in the gas phase, the analogous reactions in the aqueous phase have not been adequately studied. In this work, the reaction rate constants of ammonia, dimethylamine (DMA) and diethylamine (DEA) with hydroxyl radicals in the aqueous phase were investigated using ion chromatography. The neutral and protonated forms of each base were shown to have differing rate constants with OH by performing the measurements over a range of pH from 7.0 to 11.0. Excess hydrogen peroxide was used as the precursor for hydroxyl radicals, while monochloroacetic acid and benzoic acid were chosen as the reference compounds for the relative rate method. The rate constants of both protonated forms and neutral forms were calculated for DMA ((9.5 ± 1.2) ×106 M−1 s−1 and (3.3 ± 0.2) ×109 M−1 s−1) and DEA ((1.5 ± 0.4) × 108 M−1 s−1 and (4.9 ± 0.1) × 109 M−1 s−1) using the relative rate method. The rate constant of ammonium ion and neutral ammonia were calculated to be (2.3 ± 0.5) × 106 M−1 s−1 and (1.8 ± 0.4) × 108 M−1 s−1, respectively. With a pKa of 9.25, the rate constant of the protonated form is applicable to the overall rate constant of ammonia at pH

Cell/particle concentration inside droplets holds great potential in extending lab-in-a-droplet applications, typically ranging from biological and chemical assays. Herein, we present a universal, massive and versatile technique, namely, alternating current electrothermal-flow field-effect transistor (ACET-FFET) to accomplish in-droplet cell/synthetic particle concentration on demand. Three parallel planar electrodes are utilized to generate an artificially reorderable electric field inside droplets by tuning the gate voltage through field-effect control, which results in a reshapable ACET-based microvortices pattern for in-droplet concentration. A downstream Y-shaped junction promotes the mother droplet splitting into two daughter droplets containing highly and poorly concentrated cells/particles, respectively. Fluorescent polystyrene (PS) nanoparticles are used to characterize the variations of ACET-microvortices flow pattern formation within droplets. Moreover, the concentration performance is demonstrated using PS microparticles and Neurospora crassa cells. We show that particles/cells can flexibly accumulate into any daughter droplet or be equally concentrated in both daughter droplets by conveniently regulating the gate voltage. The highly concentrated cells at the entrance of the concentrator show an instantaneous response performance to the external electric field. Further, online simultaneous particle synthesis and concentration inside droplets are proposed and implemented for the first time, demonstrated by efficient in-droplet micromixing and Prussian blue (PB) reaction. The accompanying synthetic PB particles are highly concentrated into either daughter droplet, thereby extending the versatility of the platform. The presented in-droplet concentration strategy, together with its unique features of simple geometric configuration, facile operation and broad applicability can broaden utility in droplet microfluidics.

Biosensing applications are driving an increase in demand for low-cost photodetectors with sensitivity between 1000 and 1400 nm. Recently, the sensitivity of Ag2Se colloidal quantum dot based devic...

Liver fibrosis is a severe health problem worldwide, and it is characterized by the activation of hepatic stellate cells (HSCs) and excessive deposition of collagen. Prolonged arsenic exposure can induce HSCs activation and liver fibrosis. In the present study, the results showed that chronic NaAsO2 ingestion could result in liver fibrosis and oxidative stress in Sprague-Dawley rats, along with representative collagen deposition and HSCs activation. In addition, the inositol-requiring enzyme 1α (IRE1α)-endoplasmic reticulum (ER)-stress pathway was activated, and the activity of nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) was upregulated in rat livers. Simultaneously, the excessive production of reactive oxygen species (ROS) could induce HSCs activation, and NOX4 played an important role in generating ROS in vitro. Moreover, ER stress occurred with HSCs activation at the same time under NaAsO2 exposure, and during ER stress, the IRE1α pathway was responsible for NOX4 activation. Therefore, inhibition of IRE1α activation could attenuate the HSCs activation induced by NaAsO2 . In conclusion, the present study manifested that inorganic arsenic exposure could activate HSCs through IRE1α/NOX4-mediated ROS generation.

n-Butyl acetate is an important food additive commonly produced via concentrated sulfuric acid catalysis or immobilized lipase catalysis of butanol and acetic acid. Compared with chemical methods, ...

Evolved gases from AdBlue decomposition with different catalysts (Ti, Zr, Pt, SiO2, and γ-Al2O3) were analyzed with a thermogravimetric analyzer coupled to a mass spectrometer (TG-MS). Kinetic parameters of AdBlue decomposition process were calculated by Kissinger–Akahira–Sunoe (KAS) and Flynn–Wall–Ozawa (FWO) methods. The results show that γ-Al2O3 is the best pyrolysis catalyst, and it promotes the decomposition of urea. The gaseous products (H2O, NH3, CHNO, CO2) were detected by MS at different reaction stages, resulting from the decomposition of urea and the formation of intermediate products. With the KAS method, the calculated activation energies with the same fractional conversion for three stages are 133.20 ± 3.71–151.14 ± 7.78 kJ/mol, 128.93 ± 3.13–186.09 ± 3.92 kJ/mol, and 326.00 ± 17.58–465.09 ± 17.62 kJ/mol, respectively.

Purely organic materials showing room temperature phosphorescence (RTP) and ultralong RTP (OURTP) have recently attracted much attention. However, it is challenging to integrate circularly polarized luminescence (CPL) into RTP/OURTP. Here, we show a strategy to realize CPL-active OURTP (CP-OURTP) by binding an achiral phosphor group directly to the chiral center of an ester chain. Engineering of this flexible chiral chain enables efficient chirality transfer to carbazole aggregates, resulting in strong CP-OURTP with a lifetime of over 0.6 s and dissymmetry factor of 2.3×10-3 after the conformation regulation upon photo-activation. The realized CP-OURTP is thus stable at room temperature but can be deactivated quickly at 50 °C to CP-RTP with high CPL stability during the photo-activation/thermal-deactivation cycles. Based on this extraordinary photo/thermal-responsive and highly reversible CP-OURTP/RTP, a CPL-featured lifetime-encrypted combinational logic device has been successfully established.

The rapid improvements in the performance of organic–inorganic perovskite solar cells have been astonishing but their commercialized production requires further achievements on device stability and efficiency. Herein, we introduce a bifunctional additive, biuret, with multiple Lewis base groups to regulate the crystallization process of perovskite crystals and passivate the defects at grain boundaries. Compared with the control, methylammonium lead iodide (MAPbI3), films processed with biuret exhibit increased grain size, reduced trap state density, and more uniform local photoluminescence. The addition of biuret leads to suppressed trap-assisted nonradiative recombination and an efficiency improvement from 18.26% to 21.16%, which is among the highest efficiency for MAPbI3 solar cells with the mesoscopic structure. Meanwhile, as biuret interacts with uncoordinated Pb2+ and iodide from the iodoplumbate complex on two adjacent perovskite grains, the thermal durability of the MAPbI3 film is enhanced due to the crosslink through chemical bonding. Under 85 °C annealing in nitrogen, the biuret-modified device retains 94% of its initial efficiency after 12 days while the control cells lose more than half the efficiency.

Here, we demonstrate use of a Mg2+-dependent, site-specific DNA enzyme (DNAzyme) to cleave oligos from polyacrylamide gel beads, which is suitable for use in drop-based assays. We show that cleavage efficiency is improved by use of a tandem-repeat cleavage site. We further demonstrate that DNAzyme-released oligos function as primers in reverse transcription of cell-released mRNA.

Objective: Diabetic cardiomyopathy (DCM) is a serious complication of type 2 diabetes mellitus (T2DM), resulting in unfavorable prognosis. Icariin (ICA) is a major flavonoid isolated from the traditional oriental herbal medicine Epimedium that has been recently proved to show potential therapeutic efficacy on T2DM. The aim of this study was to investigate the underlying mechanism of how ICA improved DCM in rat models. Methods: To corroborate myocardial improvement by ICA, we managed to establish the T2DM rat model by streptozotocin (STZ) administration and high-glucose-high-fat diet. Results: The rats with T2DM showed severe insulin resistance, left ventricular dysfunction, aberrant lipids deposition, cardiac inflammation, and fibrosis compared with the control group. All these pathological symptoms were ameliorated by the treatment of ICA. The levels of extracellular matrix proteins of heart tissue significantly declined in ICA-treated rats. Conclusion: ICA may exert as a protector in T2DM-induced DCM by reducing extracellular matrix proteins in the heart tissue, implicating its potential role for the treatment of human DCM.

Organic semiconductors with bipolar charge transporting character are promising for optoelectronic applications, but the molecular design strategies of bipolar materials mostly rely on donor–acceptor systems, requiring both donor and acceptor functional units joined together to respond to the hole and electron injection/transport, respectively. Here, we show that the bipolar character can be alternatively achieved by facilitating resonance enantiomer transitions in donor-resonance-donor (D-r-D) architecture for a very small variation energy (0.4 eV) based on a newly developed resonance linkage, N–CO. Without the intrinsic participation of acceptor units, the D–r–D molecule exhibits a high triplet energy (3.01 eV) and excellent charge transport balancing ability, where one carbazole responds for hole transport and the other positively charged carbazole in the enantiotropic N+C–O− canonical form for electron transport. Benefiting from the in situ dynamic response of this facile resonance variation, the blue phosphorescent organic light emitting diodes (OLEDs) and thermally activated delayed fluorescence OLEDs employing the D–r–D molecule as the host show high maximum external quantum efficiencies of 31.2% and 20.5%, respectively. These outstanding device performances with the aid of the new concept of resonance-driven acceptor-free bipolar D–r–D host molecule illustrate exciting progress in designing dynamically bipolar organic semiconductors for high-performance optical and electronic applications.

Nitrogen (N) has a unique place in agricultural systems with large requirements. To achieve optimal nitrogen management that meets the needs of agricultural systems without causing potential environmental risks, it is of great significance to increase N use efficiency (NUE) in agricultural systems. A chlorophyll meter, for example, the SPAD-502, can provide a simple, nondestructive, and quick method for monitoring leaf N status and NUE. However, the SPAD-based crop leaf’s N status varies greatly due to environmental factors such as CO2 concentration ([CO2]) or temperature variations. In this study, we conducted [CO2] (ambient and enriched up to 500 μmol moL1) and temperature (ambient and increased by 1.5~2.0 °C) controlled experiments from 2015 to 2017 and in 2020 in two Free-Air CO2 Enrichment (FACE) sites. Leaf characters (SPAD readings, chlorophyll a + b, N content, etc.) of seven rice cultivars were measured in this four year experiment. Here, we provide evidence that SPAD readings are significantly linearly correlated with rice leaf chlorophyll a + b content (chl a + b) and N content, while the relationships are profoundly affected by elevated [CO2] and warming. Under elevated [CO2] treatment (E), the relationship between chl a + b content and N content remains unchanged, but SPAD readings and chl a + b content show a significant difference to those under ambient (A) treatment, which distorts the SPAD-based N monitoring. Under warming (T), and combined elevated [CO2] and warming (ET) treatments, both of the relationships between SPAD and leaf a + b content and between leaf a + b content and N content show a significant difference to those under A treatment. To deal with this issue under the background of global climate change dominated by warming and elevated [CO2] in the future, we need to increase the SPAD reading’s threshold value by at least 5% to adjust for applying N fertilizer within the rice cropping system by mid-century.

Staphylococcus aureus (S. aureus) is a common pathogenic bacterium that induces a variety of diseases in humans and animals. The significant pathogenicity of S. aureus is due to its expression of several virulence factors. Alpha-hemolysin (Hla) has attracted attention as a virulence factor in staphylococcal pathogenesis and has been the predominant focus of intense research. In this study, we found that kaempferol, a flavonoid compound, inhibited hemolysis at a low concentration (32 μg/mL) and exerted no effect on bacterial growth. Western blot and RT-qPCR assays further demonstrated that kaempferol downregulated the expression of Hla in S. aureus. We observed that kaempferol alleviated the damage from S. aureus Hla in A549 cells. More importantly, kaempferol showed a potent protective effect on mice pneumonia induced by MRSA, as evidenced by a significant improvement in the survival of mice, a reduction in the number of colonized colonies in lung tissue and a decrease in the pathological damage to lung tissues. In summary, the results demonstrate the protective effect of kaempferol on MRSA-induced lethal pneumonia in mice and indicate that kaempferol could be developed as a potential anti-MRSA drug.

Three phosphine sulfide-based bipolar host materials, viz&nbsp, CzPhPS, DCzPhPS, and TCzPhPS, were facilely prepared through a one-pot synthesis in excellent yields. The developed hosts exhibit superior thermal stabilities with the decomposition temperatures (Td) all exceeding 350 °C and the melting temperatures (Tm) over 200 °C. In addition, their triplet energy (ET) levels are estimated to be higher than 3.0 eV, illustrating that they are applicable to serve as hosts for blue phosphorescent organic light-emitting diodes (PhOLEDs). The maxima luminance, current efficiency (CE), power efficiency (PE), and external quantum efficiency (EQE) of 17223 cd m−2, 36.7 cd A−1, 37.5 lm W−1, and 17.5% are achieved for the blue PhOLEDs hosted by CzPhPS. The PhOLEDs based on DCzPhPS and TCzPhPS show inferior device performance than that of CzPhPS, which might be ascribed to the deteriorated charge transporting balance as the increased number of the constructed carbazole units in DCzPhPS and TCzPhPS molecules would enhance the hole-transporting ability of the devices to a large extent. Our study demonstrates that the bipolar hosts derived from phosphine sulfide have enormous potential applications in blue PhOLEDs, and the quantity of donors should be well controlled to exploit highly efficient phosphine sulfide-based hosts.

Ynamides, though relatively more stable than ynamines, are still moisture-sensitive and prone to hydration especially under acidic and heating conditions. Here we report an environmentally benign, robust protocol to synthesize sulfonamide-based ynamides and arylynamines via Sonogashira coupling reactions in water, using a readily available quaternary ammonium salt as the surfactant.

Astaxanthin (AST) is a naturally occurring carotenoid with potent anti-oxidative and anti-inflammatory potency against chronic diseases. In this study, we suspended AST in different nonionic emulsifiers to produce nanodispersions. The basic physicochemical properties of the produced AST nanodispersions were verified to select the optimized nonionic emulsifier. Among the tested emulsifiers, Polysorbate 20 produced the AST nanoemulsions with smaller particle diameters, narrower size distributions, and higher AST contents among these emulsifiers. The N-methyl-N-nitrosourea (MNU) administered mouse is a chemically induced retinal degeneration (RD) model with rapid progress rate. AST suspended in Polysorbate 20 was demonstrated to ameliorate the dramatic consequences of MNU on retina architectures and function in several different tests encompassing from electrophysiology to histology and molecular tests. Furthermore, the multi-electrodes array (MEA) was used to detect the firing activities of retinal ganglion cells within the inner retinal circuits. We found that AST nanodispersions could restrain the spontaneous firing response, enhance the light induced firing response, and preserve the basic configurations of visual signal pathway in degenerative retinas. The MEA assay provided an appropriate example to evaluate the potency of pharmacological compounds on retinal plasticity. In summary, emulsifier type affects the basic physicochemical characteristic of AST nanodispersions. Polysorbate 20 acts as an optimized nonionic emulsifier for the efficient delivery of AST nanodispersions to retina. AST nanodispersions can alleviate the photoreceptor loss and rectify the abnormities in visual signal transmission.

Bipolar host materials consisting of electron-donating (D) and -accepting (A) moieties are significant advances in broadening the recombination zone to suppress the quenching effects of emissive ph...

Sulfur oxides (SOx) are important atmospheric trace species in both gas and particulate phases, and sulfate is a major component of atmospheric aerosol. One potentially important source of particulate sulfate formation is the oxidation of dissolved SO2 by organic peroxides, which comprises a major fraction of secondary organic aerosol (SOA). In this study, we investigated the reaction kinetics and mechanisms between SO2 and condensed-phase peroxides. pH-dependent aqueous phase reaction rate constants between S(IV) and organic peroxide standards were measured. Highly oxygenated organic peroxides with O/C > 0.6 in α-pinene SOA react rapidly with S(IV) species in the aqueous phase. The reactions between organic peroxides and S(IV) yield both inorganic sulfate and organosulfates (OS), as observed by electrospray ionization ion mobility mass spectrometry. For the first time, 34S-labeling experiments in this study revealed that dissolved SO2 forms OS via direct reactions without forming inorganic sulfate as a reactive intermediate. Kinetics of OS formation was estimated semiquantitatively, and such reaction was found to account for 30-60% of sulfur reacted. The photochemical box model GAMMA was applied to assess the implications of the measured SO2 consumption and OS formation rates. Our findings indicate that this novel pathway of SO2-peroxide reaction is important for sulfate formation in submicron aerosol.

Hydrogenation of p-nitrophenol (PNP) towards the conversion to p-aminophenol (PAP) by metal catalysis is known as a simple and eco-friendly technique for the production of corresponding industrial and pharmaceutical intermediates. While continuous efforts are paid for more sustainable and greener procedures by using transition metal catalysts, atomic-precise reaction mechanism for the PNP-to-PAP is still illusive to be fully understood. Utilizing a dry-wet combined strategy, here we have synthesized water-soluble Pd8 nanoclusters (NCs) with mercaptosuccinic acid (H2SMA) as the ligand, and the Pd8 NCs found high catalytic performance for the conversion of PNP-to-PAP, as identified by the electrospray ionization mass spectrometer (ESI-MS) measurement. The gradual changes over time of ultraviolet–visible (UV–vis) spectra of PNP really display the catalytic reduction by NaBH4 in presence of Pd8 NCs. Further, in-depth charge transfer interactions between PNP and the Pd8 clusters at the proton-rich conditions are investigated by natural bond orbital (NBO) analysis and electron density difference (EDD) analysis. The exothermic and kinetic-favorable reaction pathways are addressed, based on successive PNP hydrogenation and H2O removal processes, clarifying the reaction mechanism of Pd catalysts. It is worth noting that this solid-state synthetic route for such Pd8 clusters enables gram-scale quantity of production in likely practical use.

In this study, 10-year records of PM2.5 oxalate concentrations in six urban and rural Canadian monitoring sites are analyzed along with the time series of other water-soluble ionic components, wate...

Streptococcus mutans (S. mutans) adheres to the tooth surface, metabolizes carbohydrates, and produces acid products, leading to enamel demineralization-the onset of dental caries. Rapid acidification by S. mutans has been observed in the presence of glucose. However, little is known about the role of small RNAs (sRNAs) in S. mutans in the presence of glucose and their relationship to tooth adherence. The objective of this study was to evaluate the role of sRNAs in S. mutans (18-50 nucleotides) regarding adherence capacity under 1% and 5% glucose concentrations. The pH drop and adherence capacity in the 1% glucose condition were similar to these parameters under conditions of 5% sucrose that were published in our previous study. A total of 2149 candidate sRNA with at least 100 average reads in the 5% and 1% glucose libraries were obtained. Between the two libraries, 581 sRNAs were differentially expressed and 43 sRNAs were verified. However, the expression levels of the predicted target genes gtfC and spaP were similar between the 1% and 5% glucose conditions. The bioinformatic analysis suggested that differentially expressed sRNAs may be involved in several pathways. These findings indicate that sRNAs were induced under these glucose concentrations and a series of sRNAs were specifically induced, respectively. sRNAs that are induced under glucose stress may be involved in regulating adherence of S. mutans.

Objective Retinitis pigmentosa causes progressive photoreceptor degeneration in the subjects while no clinical therapy exists. The present study sought to evaluate the potential protective effects of taurine on a pharmacologically induced RP animal model. Methods Photoreceptor degeneration in mice was induced by an intraperitoneal injection of N-methyl-N-nitrosourea (MNU). The MNU-administrated mouse received taurine treatment and then they were examined by electroretinography, spectral-domain optical coherence tomography, optokinetic test, and histological and immunohistochemistry assay. Results Prominent taurine deficiency was found in the retinas of MNU-administered mice. Intravenous taurine treatment increased significantly the retinal taurine level. Morphological studies showed that taurine could alleviate the retinal disorganizations in the MNU-induced mice. Taurine also ameliorated the visual impairments in the MNU-induced mice as evidenced by functional examinations. Immunostaining experiments demonstrated that both the M-cone and S-cone populations in the degenerative retinas are rescued by taurine. In particular, the M-cone photoreceptors in superior-temporal quadrant and the S-cone photoreceptors in inferior-nasal quadrant were preferentially rescued. Mechanism study showed that the photoreceptor apoptosis and oxidative stress in the degenerative retina were effectively alleviated by taurine treatment. Conclusion Taurine is protective against the MNU-induced photoreceptor degeneration. Systemic taurine administration may act as a promising therapeutic potion for retinopathies with chronic cycle.

Aerosol pH is difficult to measure directly but can be calculated if the chemical composition is known with sufficient accuracy and precision to calculate the aerosol water content and the H+ concentration through the equilibrium among acids and their conjugate bases. In practical terms, simultaneous measurements of at least one semi-volatile constituent, e.g. NH3 or HNO3, are required to provide a constraint on the calculation of pH. Long-term records of aerosol pH are scarce due to the limited monitoring of NH3 in conjunction with PM2.5. In this study, 10-year (2007–2016) records of pH of PM2.5 at six eastern Canadian sites were calculated using the E-AIM II model with the input of gaseous NH3, gaseous HNO3 and major water-soluble inorganic ions in PM2.5 provided by Canada's National Air Pollution Surveillance (NAPS) Program. Clear seasonal cycles of aerosol pH were found with lower pH (∼2) in summer and higher pH (∼3) in winter consistently across all six sites, while the day-to-day variations of aerosol pH were higher in winter compared to summer. Tests of the sensitivity of aerosol pH to meteorological parameters demonstrate that the changes in ambient temperature largely drive the seasonal cycle of aerosol pH. The sensitivity of pH to chemical composition shows that pH has different responses to the changes in chemical composition in different seasons. During summertime, aerosol pH was mainly determined by temperature with limited impact from changes in NHx or sulfate concentrations. However, in wintertime, both meteorological parameters and chemical composition contribute to the variations in aerosol pH, resulting in the larger variation during wintertime. This study reveals that the sensitivity of aerosol pH to chemical composition is distinctly different under different meteorological conditions and needs to be carefully examined for any particular region.

Retinal degeneration (RD) results in photoreceptor loss and irreversible visual impairments. This study sought to alleviate the photoreceptor degeneration via the adeno-associated virus (AAV)-mediated erythropoietin (EPO) therapy. AAV-2/2-mCMV-EPO vectors were constructed and delivered into the subretinal space of a RD model. The retinal morphology, optokinetic behaviour and electrophysiological function of the treated animals were analysed. The subretinal delivery of AAV-2/2 vectors induced robust EPO gene expressions in the retinas. AAV2/2-mediated EPO therapy ameliorated the photoreceptor degeneration and visual impairments of the RD animal model. Furthermore, the multi-electrodes array (MEA) was used to detect the firing activities of retinal ganglion cells. MEA recording showed that the EPO therapy could restrain the spontaneous firing response, enhance the light-induced firing response and preserve the basic configurations of visual signal pathway in RD model. Our MEA assay provided an example to evaluate the potency of pharmacological compounds on retinal plasticity. In conclusion, AAV2/2-mediated EPO therapy can ameliorate the photoreceptor degeneration and rectify the abnormities in visual signal transmission. These beneficial results suggest the AAV vector is a viable therapeutic option for retinopathies with rapidly degenerating kinetics and lay the groundwork for future development of EPO gene therapy.

A series of 6-alkoxy-3-aryl-[1,2,4]triazolo[4,3- b][1,2,4,5] tetrazine derivatives is synthesized and evaluated for their antitumor activities. These compounds exhibit potent antiproliferative activities against A549, Bewo, and MCF-7 cells. Molecular docking is performed to study the inhibitor–c-Met kinase interactions, and the results show that 6-ethoxyl-3-phenylethyl-[1,2,4]triazolo[4,3- b][1,2,4,5] tetrazine is potently bound to c-Met kinase with two hydrogen bonds and one π–π interaction. Based on these preliminary results, it is thought that compound 6-ethoxyl-3-phenylethyl-[1,2,4]triazolo[4,3- b][1,2,4,5] tetrazine with potent inhibitory activity may be a potential anticancer agent.

Indoleacetic acid (IAA)-carbendazim was synthesized to assess whether this conjugate could retain the fungicidal activity of carbendazim and gain root-inducing properties upon the addition of an indoleacetic acid group. An indoor virulence test demonstrated that the conjugate retained the fungicidal activity of carbendazim towards Cylindrocladium parasiticum. The conjugate was detected in roots after soaking Ricinus communis L. leaves into a solution of the IAA-carbendazim, which confirmed its phloem mobility. The activities of the cellulase, polygalacturonase and xylanase produced by Cylindrocladium parasiticum treated with different concentrations of the conjugate were determined, and the peak activities appeared at 72 h or 96 h. More importantly, the conjugate showed the ability to promote root growth. These results revealed that indoleacetic acid-carbendazim may be useful in preventing Cylindrocladium parasiticum and other diseases.

The performance of printed radio frequency identification (RFID) antennas is highly dependent on the electrical conductivity of the conducting tracks forming the antennas. In this paper, screen printed high frequency (HF) RFID antennas on polyethylene terephthalate (PET) film are reported, with the focus on the optimization of the post-processing procedures for the improvement of the conductivity of the screen printed conductive tracks. The electrical conductivity of the printed conductive tracks is significantly affected by the ink post printing processing conditions. The results show that drying the ink at ambient temperature, followed by heat treatment provides the optimum conductivity. This treatment also offers the highest quality factors for the screen printed HF RFID antennas. It was also found that pre-drying at 60 °C followed by heat treatment achieves similar results with less processing time. The findings provide a low cost solution for screen printing high performance HF RFID antennas on plastic films.

The simultaneous production of acetate from bicarbonate (from CO2 sequestration) and hydrogen gas, with concomitant removal of Cd(II) heavy metal in water is demonstrated in multifunctional metallurgical microbial electrosynthesis systems (MES) incorporating Cd(II) tolerant electrochemically active bacteria (EAB) (Ochrobactrum sp. X1, Pseudomonas sp. X3, Pseudomonas delhiensis X5, and Ochrobactrum anthropi X7). Strain X5 favored the production of acetate, while X7 preferred the production of hydrogen. The rate of Cd(II) removal by all EAB (1.20–1.32 mg/L/h), and the rates of acetate production by X5 (29.4 mg/L/d) and hydrogen evolution by X7 (0.0187 m3/m3/d) increased in the presence of a circuital current. The production of acetate and hydrogen was regulated by the release of extracellular polymeric substances (EPS), which also exhibited invariable catalytic activity toward the reduction of Cd(II) to Cd(0). The intracellular activities of glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and dehydrogenase were altered by the circuital current and Cd(II) concentration, and these regulated the products distribution. Such understanding enables the targeted manipulation of the MES operational conditions that favor the production of acetate from CO2 sequestration with simultaneous hydrogen production and removal/recovery of Cd(II) from metal-contaminated and organics-barren waters.

Molecular conformation plays an important role in tuning the packing modes of organic optoelectronic materials to achieve enhanced and/or balanced charge transport. Here, we introduce the noncovalent intramolecular interactions to the host materials of phosphorescent organic light-emitting diodes (PhOLEDs). Different numbers and/or positions of intramolecular CH···N noncovalent interactions were constructed by using different N-heterocycles of pyridine, pyrimidine, and pyrazine as acceptor units and carbazole as the donor unit in a donor-acceptor-donor (D-A-D) motif. Thus, designed D-A-D molecules were synthesized facilely through a one-step Ullmann reaction in high yields, showing varied intramolecular interactions to regulate the molecular conformation significantly. Impressively, owing to the quasi-parallel molecular conformation, which is beneficial for forming facile transporting channels of both holes and electrons, the newly designed host material of 9,9′-(pyridine-2,5-diyl)bis(9H-carbazole) exhibits good device performance of blue PhOLEDs with current, power, and external quantum efficiencies up to 33.0 cd A–1, 32.1 lm W–1, and 16.3%, respectively. This work highlights the significant importance of the noncovalent interactions in designing advanced organic semiconductors for high-performance optoelectronic devices.

Low-level inorganic arsenic (iAs) in drinking water is a risk factor for β cells dysfunction. Taurine (Tau) is a kind of semi-essential β amino acid, and beneficial for β cell function. However, the effects of Tau on arsenic trioxide (As2O3) induced β cells dysfunction and related mechanisms are still uncertain. Here, we found that Tau relieved As2O3-induced endoplasmic reticulum (ER) stress, inflammation and pyroptosis in rat pancreas. In INS-1 cells, with NOD-like receptor family pyrin domain-containing 3 (NLRP3) inhibitor pretreatment, As2O3-induced activation of pyroptosis was decreased; with tumor necrosis factor-α (TNF-α) inhibitor pretreatment, As2O3-induced activation of NLRP3 inflammasome and pyroptosis were decreased; further, with the inositol-requiring enzyme 1 alpha (IRE1α) inhibitor, As2O3-induced induction of TNF-α was decreased. Tau markedly protected As2O3-induced β cells dysfunction by reducing the phosphorylation of IRE1α, production of TNF-α, activation of NLRP3 inflammasome and pyroptosis. Our results revealed that ER stress dependent inflammation and pyroptosis are critical pathogenic components of As2O3-induced β cell dysfunction. Moreover, TNF-α was a critical signaling node that linked As2O3-induced ER stress and pyroptosis. Tau was an effective supplement against As2O3-induced β cells dysfunction through the pathway as mentioned above.

Thermal-based microparticle focusing has recently received increasing attention due to its noninvasive nature and simple manipulation mechanism. However, its further application is limited by current complicated fluid heating systems and low particle focusing velocity. Using simple indium tin oxide-made microheaters, herein we propose a flexible and novel approach for efficient particle focusing based on direct current-induced thermal buoyancy convection. Importantly, for avoiding possible electrochemical reactions on the electrode, the microheaters are isolated from the granular fluids of interest by a thin glass slide. The concentration performance of the designed chip was first demonstrated by statically focusing 4-μm silica particles, yeast cells, silica particles in insulating buffer, and 100-nm copper microspheres. Also the trapping of a mixture of 5-μm and 2-μm polystyrene microbeads indicated that the chip can either simultaneously concentrate two kinds of particles or selectively focus the heavier ones by adjusting the voltages. Then the different concentration patterns of microbeads exhibited that the microspheres can be flexibly manipulated by changing the configurations of microheaters. Furthermore, for the first time, we achieved thermal-based continuous particle focusing in both conducting and insulating solutions using buoyancy convection, demonstrating that this method can be utilized to achieve both static and continuous particle manipulations in multiple liquid media. Finally, the feasibility of this device in effective wear measurement of machines was demonstrated by conducting systematic experiments of focusing nanocopper particles in the hydraulic oil. Therefore, this presented approach would be promising for a broad range of on-chip applications.

Desert ecosystems are nitrogen-limited, and highly responsive to even small inputs of nitrogen. Recently, desert ecosystems have been affected by increasing levels of nitrogen deposition, which may lead to changes in greenhouse gas efflux. However, the effects of nitrogen deposition on these gases in the desert ecosystems remain poorly understood. To study the dynamics in greenhouse gases under increasing nitrogen, six rates of simulated nitrogen deposition, including 0(N0), 0.5(N0.5), 1.0(N1), 3.0(N3), 6.0(N6), 24.0 (N24) g nitrogen m−2 a−1, were applied in soils of the Gurbantunggut Desert in Central Asia. Efflux of nitrous oxide (N2O), methane (CH4), ecosystem respiration and net carbon ecosystem exchange were measured across two growing seasons for two years. The efflux of the four gases changed greatly in different seasons, which can explain more variation than nitrogen treatments except for N2O. Nitrogen input stimulated N2O emission, especially in the high nitrogen treatments, with N2O emission 1.6 (N6) and 2.6 (N24) times greater than control (N0). However, N2O exchange also depended on the seasons, while only minor changes were found in some seasons (late spring 2010 and late summer 2011). Overall, CH4 uptake (average 31.4 μg m−2 h−1) was not significantly affected by the nitrogen addition. At the high nitrogen treatment levels, ecosystem respiration decreased in the late spring and summer of the second year, with similar responses to nitrogen addition in mid-autumn between two years. Net ecosystem carbon exchange also showed gradual responses to nitrogen addition overall, but did not differ significantly across seasons and treatments. Overall, structural equation models showed that the dynamics in N2O were mostly attributed to variations in nitrogen addition, CH4 to soil moisture (or temperature), ecosystem respiration to plant species richness (or density) and net ecosystem carbon exchange to soil moisture (or temperature). Our study indicates that the changes in greenhouse gas emissions caused by nitrogen deposition in short time scale were small in these desert soils.

The activation of hepatic stellate cells (HSCs) is a key event in the development of hepatic fibrosis caused by arsenic. However, it is unclear how arsenic induces the activation of HSCs. In the present study, we found that arsenic trioxide (As2O3) induced liver tissue damage, stimulated autophagy and HSCs activation, and increased collagen accumulation in the liver of mice. Supplemented with taurine (Tau) attenuated the changes mentioned above caused by As2O3. In human hepatic stellate cell line LX-2 cells, we found that As2O3-induced activation of HSCs was autophagy-dependent, and we found that peroxisome proliferator activated receptors alpha (PPARα) played an important role in arsenic-induced HSCs activation. In addition, inhibiting autophagy and PPARα alleviated the activation of HSCs and lipid droplet loss induced by As2O3. Moreover, we found that Tau alleviated As2O3-induced elevation of autophagy and PPARα expression, and activation of the HSCs. Our results indicated that autophagy was regulated by PPARα and was involved in lipid droplet loss during the activation of HSCs. Tau alleviated As2O3-induced HSCs activation by inhibiting the PPARα/autophagy pathway. These findings give an innovative insight into the association of PPARα, autophagy, the activation of HSCs and hepatic fibrosis induced by As2O3.

Surface energy incompatibility between ink and substrate is a significant obstacle for inkjet printing of electronic components, causing printed lines to dewet and break apart. In this paper, it was demonstrated that smooth, continuous silver lines could be printed via control of ink-substrate interactions, despite the tendency of the ink to dewet from the substrate. The silver lines were printed using drop-on-demand inkjet printing of silver nanoparticle ink onto non-crosslinked SU-8 coated polyethylene terephthalate (PET). The lines were subsequently heated to control dewetting and cause contraction from $60~\mu \text{m}$ to $14~\mu \text{m}$ . The SU-8 film underneath the silver line was dissolved and redistributed to form a ridged concave structure that prevented the lines from bulging and breaking apart. Additionally, photonic sintering was used to achieve low resistivity of $0.06~{\mu } {\Omega }\text{m}$ for the narrow printed lines.

Backbone engineering was performed on highly rigid semiconducting polymers to include diketopyrropyrrole (DPP) units combined with pyrazine-containing moieties. These new moieties were shown to improve backbone planarity through a conformational locking effect between nitrogen and sulfur atoms. The new polymers, characterized by various techniques, were shown to possess a highly crystalline and smooth solid-state morphology, optimal for charge transport. To verify the potential of the new semiconductor for organic electronics, a series of organic field-effect transistors was fabricated. Interestingly, the new polymer was shown to possess a charge mobility of 0.27 cm² V⁻¹ s⁻¹ and on/off current ratio of 10⁷, which is an improvement when compared to a thiophene analogue. More importantly, the polymer led to devices with high stability, with a retention of device characteristics when exposed to the same bias stress comparable to a benchmark reference polymer. The utilization of pyrazine-containing moieties as a conformational lock is a promising strategy to achieve a high performance conjugated polymer in a simple manner. Moreover, their utilization in bottom-gate bottom-contact devices highlights the potential of this new semiconductor for fully printed high-performance electronics.

The gas/particle phase partitioning behavior of NH3/NH4+ and other semivolatile constituents was measured by a custom-designed Denuder-MOUDI-Denuder integrated sampling system in Toronto, Canada. In this setup, upstream denuders were used to capture alkaline and acidic gaseous components, and particle phase components were captured by the filters on MOUDI stages. Downstream denuders captured any alkaline and acidic gases that exited the MOUDI apparatus, likely representing semivolatile constituents. In the ambient gas phase HCOOH was the most abundant acidic gas, with an average mixing ratio ∼2–3 times higher than that of SO2 and HNO3. It was found that the majority (49–96%) of filter-collected NH4+ volatilized during collection. NO3– volatilization could only explain 0.9–15% of NH4+ loss from the filters. Instead, a strong correlation and nearly 1:1 molar ratio between downstream HCOO– and NH4+ indicated that most of the semivolatile NH4+ was originally balanced by organic acids in the ambient particle p...

Six Co(II) complexes were synthesized from CoCl2 with positional isomeric ligands: 3-(pyridine-3-yl)-5-(2-methoxyphenol-6-yl)-1H-1,2,4-triazole (3-H2pmpt) and 4-(pyridine-3-yl)-5-(2-methoxyphenol-6-yl)-1H-1,2,4-triazole (4-H2pmpt), namely, {[Co3(3-pmpt)2Cl2(DMF)2]·(DMF)2}n (1), {[Co3(4-pmpt)2Cl2(DMF)2]·(DMF)}n (2), [Co3(3-pmpt)2Cl2(DMF)2]n (3), [Co3(4-pmpt)2Cl2(DMF)2]n (4), {[Co5(3-pmpt)4(HCO2)2(DMF)2]·(H2O)4}n (5), {[Co5(4-pmpt)4(HCO2)2(H2O)2]·(H2O)6}n (6). Structural analysis reveals that pmpt isomers display different coordination modes to manage Co(II) ions to form [Co3] subunits in 1–4, and [Co5] subunits in 5–6, respectively. Which are further extended via different pyridine ring N-orientation to build the 1-D chains (for 1, 5 and 6) and 2-D layers (for 2, 3 and 4). Structural analysis indicate that 3/4-pmpt is an excellent multi-connect linker with pyridine ring at different angles, has an important effect on the structural topologies of such Co(II) complexes. Magnetic susceptibilities reveal weak ferromagnetic and antiferromagnetic exchange interactions between the adjacent metal centers in 5 and 6.

A phosphoric acid (H3PO4)-polyvinyl alcohol (PVA) electrolyte was demonstrated as a gate dielectric for electrolyte-gated field-effect transistors (EGFETs). These devices exhibited high performance with sub 1 V operation, a high ON/OFF ratio >105 and a low subthreshold swing of 90 mV/decade. The results show the strong viability of proton conducting polymer electrolytes as gate dielectrics which open the door for further development of low-power EGFETs.

Multidrug-resistant Acinetobacter baumannii (A. baumannii) causes severe and often fatal healthcare-associated infections due partly to antibiotic resistance. There are no studies on A. baumannii lipidomics of susceptible and resistant strains grown at lethal and sublethal concentrations. Therefore, we analyzed the impact of colistin resistance on glycerolipids’ content by using untargeted lipidomics on clinical isolate. Nine lipid sub-classes were annotated, including phosphatidylcholine, rarely detected in the bacterial membrane among 130 different lipid species. The other lipid sub-classes detected are phosphatidylethanolamine (PE), phosphatidylglycerol (PG), lysophosphatidylethanolamine, hemibismonoacylglycerophosphate, cardiolipin, monolysocardiolipin, diacylglycerol, and triacylglycerol. Under lethal and sublethal concentrations of colistin, significant reduction of PE was observed on the resistant and susceptible strain, respectively. Palmitic acid percentage was higher at colistin at low concentration but only for the susceptible strain. When looking at individual lipid species, the most abundant PE and PG species (PE 34:1 and PG 34:1) are significantly upregulated when the susceptible and the resistant strains are cultivated with colistin. This is, to date, the most exhaustive lipidomics data compilation of A. baumannii cultivated in the presence of colistin. This work is highlighting the plasma membrane plasticity used by this gram-negative bacterium to survive colistin treatment.

Borehole wall collapse is rare in the drilling of carbonate rock formations. However, several wells in the Maantang–Leikoupo carbonate formation have collapsed and released blocks to varying degrees, which have caused sticking and hindered efficient development of oil and gas resources. Thus, through the study of macroscopic and microscopic characteristics of carbonate rocks in this area, it is concluded that the fractures in this area are developed. In order to facilitate the analysis of formation fracture development, the concept of formation integrity coefficient which is commonly used in rock engineering was introduced. Firstly, the feasibility of using the formation integrity coefficient to characterize the degree of rock fragmentation was verified by the laboratory acoustic experiment. Finally, the empirical formulas were proposed regarding the formation integrity coefficient and the cohesion of carbonate rocks in this area by combining the laboratory mechanical experiment and acoustic experiment, and a calculation model for the collapse density considering formation integrity was established. Results provide guidance for research on carbonate wellbore stability, especially for fractured carbonate strata.

Harringtonolide (HO), a natural product isolated from Cephalotaxus harringtonia, exhibits potent antiproliferative activity. However, little information has been reported on the systematic structure−activity relationship (SAR) of HO derivatives. Modifications on tropone, lactone, and allyl positions of HO (1) were carried out to provide 17 derivatives (2–13, 11a–11f). The in vitro antiproliferative activity against four cancer cell lines (HCT-116, A375, A549, and Huh-7) and one normal cell line (L-02) was tested. Amongst these novel derivatives, compound 6 exhibited comparable cell growth inhibitory activity to HO and displayed better selectivity index (SI = 56.5) between Huh-7 and L-02 cells. The SAR results revealed that the tropone and lactone moieties are essential for the cytotoxic activities, which provided useful suggestions for further structural optimization of HO.