Lanthanide luminescence nanothermometer with working wavelength beyond 1500 nm for cerebrovascular temperature imaging in vivo.

Nanothermometers enable the detection of temperature changes at the microscopic scale, which is crucial for elucidating biological mechanisms and guiding treatment strategies. However, temperature monitoring of micron-scale structures in vivo using luminescent nanothermometers remains challenging, primarily due to the severe scattering effect of biological tissue that compromises the imaging resolution. Herein, a lanthanide luminescence nanothermometer with a working wavelength beyond 1500 nm is developed to achieve high-resolution temperature imaging in vivo. The energy transfer between lanthanide ions (Er3+ and Yb3+) and H2O molecules, called the environment quenching assisted downshifting process, is utilized to establish temperature-sensitive emissions at 1550 and 980 nm. Using an optimized thin active shell doped with Yb3+ ions, the nanothermometer's thermal sensitivity and the 1550 nm emission intensity are enhanced by modulating the environment quenching assisted downshifting process. Consequently, minimally invasive temperature imaging of the cerebrovascular system in mice with an imaging resolution of nearly 200 µm is achieved using the nanothermometer. This work points to a method for high-resolution temperature imaging of micron-level structures in vivo, potentially giving insights into research in temperature sensing, disease diagnosis, and treatment development.

An NIR-IIb emissive transmembrane voltage nano-indicator for the optical monitoring of electrophysiological activities in vivo.

In vivo transmembrane-voltage detection reflected the electrophysiological activities of the biological system, which is crucial for the diagnosis of neuronal disease. Traditional implanted electrodes can only monitor limited regions and induce relatively large tissue damage. Despite emerging monitoring methods based on optical imaging have access to signal recording in a larger area, the recording wavelength of less than 1000 nm seriously weakens the detection depth and resolution in vivo. Herein, a Förster resonance energy transfer (FRET)-based nano-indicator, NaYbF4:Er@NaYF4@Cy7.5@DPPC (Cy7.5-ErNP) with emission in the near-infrared IIb biological window (NIR-IIb, 1500-1700 nm) is developed for transmembrane-voltage detection. Cy7.5 dye is found to be voltage-sensitive and is employed as the energy donor for the energy transfer to the lanthanide nanoparticle, NaYbF4:Er@NaYF4 (ErNP), which works as the acceptor to achieve electrophysiological signal responsive NIR-IIb luminescence. Benefiting from the high penetration and low scattering of NIR-IIb luminescence, the Cy7.5-ErNP enables both the visualization of action potential in vitro and monitoring of Mesial Temporal lobe epilepsy (mTLE) disease in vivo. This work presents a concept for leveraging the lanthanide luminescent nanoprobes to visualize electrophysiological activity in vivo, which facilitates the development of an optical nano-indicator for the diagnosis of neurological disorders.

A bone-targeting near-infrared luminescence nanocarrier facilitates alpha-ketoglutarate efficacy enhancement for osteoporosis therapy.

Osteoporosis (OP), which largely increases the risk of fractures, is the most common chronic degenerative orthopedic disease in the elderly due to the imbalance of bone homeostasis. Alpha-ketoglutaric acid (AKG), an endogenous metabolic intermediate involved in osteogenesis, plays critical roles in osteogenic differentiation and mineralization and the inhibition of osteoclastogenic differentiation. However, the low bioavailability and poor bone-targeting efficiency of AKG seriously limit its efficacy in OP treatment. In this work, a bone-targeting, near-infrared emissive lanthanide luminescence nanocarrier loaded with AKG (ß-NaYF4:7%Yb, 60%Nd@NaLuF4@mSiO2-EDTA-AKG, abbreviated as LMEK) is developed for the enhancement of AKG efficacy in OP therapy. By utilizing the NIR-II luminescence (>1000 nm) of LMEK, whole-body bone imaging with high spatial resolution is achieved to confirm the bone enrichment of AKG noninvasively in vivo. The results reveal that LMEK exhibits a remarkable OP therapeutic effect in improving the osseointegration of the surrounding bone in the ovariectomized OP mice models, which is validated by the enhanced inhibition of osteoclast through hypoxia-inducible factor-1α suppression and promotion of osteogenic differentiation in osteoblast. Notably, the dose of AKG in LMEK can be reduced to only 0.2 % of the dose when pure AKG is used in therapy, which dramatically improves the bioavailability of AKG and mitigates the metabolism burden. This work provides a strategy to conquer the low utilization of AKG in OP therapy, which not only overcomes the challenges in AKG efficacy for OP treatment but also offers insights into the development and application of other potential drugs for skeletal diseases. STATEMENT OF SIGNIFICANCE: Alpha-ketoglutarate (AKG) is an intermediate within the Krebs cycle, participating in diverse metabolic and cellular processes, showing potential for osteoporosis (OP) therapy. However, AKG's limited bioavailability and inefficient bone-targeting hinder its effectiveness in treating OP. Herein, a near-infrared emissive nanocarrier is developed that precisely targets bones and delivers AKG, bolstering its effectiveness in OP therapy. Thanks to this efficient bone-targeting delivery, the AKG dosage is reduced to 0.2 % of the conventional treatment level. This marks the first utilization of a bone-targeting nanocarrier to amplify AKG's bioavailability and OP therapy efficacy. Furthermore, the mechanism of AKG-loaded nanocarrier regulating the biological behavior of osteoclasts and osteoblasts mediated is tentatively explored.

2D Nano-Channeled Molybdenum Compounds for Accelerating Interfacial Polysulfides Catalysis in Li-S Battery.

The shuttle effect, which causes the loss of active sulfur, passivation of lithium anode, and leads to severe capacity attenuation, is currently the main bottleneck for lithium-sulfur batteries. Recent studies have disclosed that molybdenum compounds possess exceptional advantages as a polar substrate to immobilize and catalyze lithium polysulfide such as high conductivity and strong sulfiphilicity. However, these materials show incomplete contact with sulfur/polysulfides, which causes uneven redox conversion of sulfur and results in poor rate performance. Herein, a new type of 2D nano-channeled molybdenum compounds (2D-MoNx ) via the 2D organic-polyoxometalate superstructure for accelerating interfacial polysulfide catalysis toward high-performance lithium-sulfur batteries is reported. The 2D-MoNx shows well-interlinked nano-channels, which increase the reactive interface and contact surface with polysulfides. Therefore, the battery equipped with 2D-MoNx displays a high discharge capacity of 912.7 mAh g-1 at 1 C and the highest capacity retention of 523.7 mAh g-1 after 300 cycles. Even at the rate of 2 C, the capacity retention can be maintained at 526.6 mAh g-1 after 300 cycles. This innovative nano-channel and interfacial design of 2D-MoNx provides new nanostructures to optimize the sulfur redox chemistry and eliminate the shuttle effect of polysulfides.

Global observational coverage of onshore oil and gas methane sources with TROPOMI.

Satellite observations have been used to measure methane (CH4) emissions from the oil and gas (O&G) industry, particularly by revealing previously undocumented, very large emission events and basin-level emission estimates. However, most satellite systems use passive remote sensing to retrieve CH4 mixing ratios, which is sensitive to sunlight, earth surface properties, and atmospheric conditions. Accordingly, the reliability of satellites for routine CH4 emissions monitoring varies across the globe. To better understand the potentials and limitations of routine monitoring of CH4 emissions with satellites, we investigated the global observational coverage of the TROPOMI instrument onboard the Sentinel-5P satellite-the only satellite system currently with daily global coverage. A 0.1° × 0.1° gridded global map that indicates the average number of days with valid observations from TROPOMI for 2019-2021 was generated by following the measurement retrieval quality-assurance threshold (≥ 0.5). We found TROPOMI had promising observational coverage over dryland regions (maximum: 58.6%) but limited coverage over tropical regions and high latitudes (minimum: 0%). Cloud cover and solar zenith angle were the primary factors affecting observational coverage at high latitudes, while aerosol optical thickness was the primary factor over dryland regions. To further assess the country-level reliability of satellites for detecting and quantifying CH4 emissions from the onshore O&G sector, we extracted the average annual TROPOMI observational coverage (TOC) over onshore O&G infrastructure for 160 countries. Seven of the top-10 O&G-producing countries had an average annual TOC < 10% (< 36 days per year), which indicates the limited ability to routinely identify large emissions events, track their duration, and quantify emissions rates using inverse modelling. We further assessed the potential performance of the latter by combining TOC and the uncertainties from the global O&G inventory. Results indicate that the accuracy of emissions quantifications of onshore O&G sources using TROPOMI data and inverse modeling will be higher in countries located in dryland and mid-latitude regions and lower in tropical and high-latitude regions. Therefore, current passive-sensing satellites have low potential for frequent monitoring of large methane emissions from O&G sectors in countries located in tropical and high latitudes (e.g., Canada, Russia, Brazil, Norway, and Venezuela). Alternative methods should be considered for routine emissions monitoring in these regions.

Nanomaterials-Enabled Physicochemical Antibacterial Therapeutics: Toward the Antibiotic-Free Disinfections.

Bacterial infection continues to be an increasing global health problem with the most widely accepted treatment paradigms restricted to antibiotics. However, the overuse and misuse of antibiotics have triggered multidrug resistance of bacteria, frustrating therapeutic outcomes, and leading to higher mortality rates. Even worse, the tendency of bacteria to form biofilms on living and nonliving surfaces further increases the difficulty in confronting bacteria because the extracellular matrix can act as a robust barrier to prevent the penetration of antibiotics and resist environmental damage. As a result, the inability to eliminate bacteria and biofilms often leads to persistent infection, implant failure, and device damage. Therefore, it is of paramount importance to develop alternative antimicrobial agents while avoiding the generation of bacterial resistance to prevent the large-scale growth of bacterial resistance. In recent years, nano-antibacterial materials have played a vital role in the antibacterial field because of their excellent physical and chemical properties. This review focuses on new physicochemical antibacterial strategies and versatile antibacterial nanomaterials, especially the mechanism and types of 2D antibacterial nanomaterials. In addition, this advanced review provides guidance on the development direction of antibiotic-free disinfections in the antibacterial field in the future.

Amorphization-Modulated Metal Sulfides with Boosted Active Sites and Kinetics for Efficient Enzymatic Colorimetric Biodetection.

Colorimetric biosensing has become a popular sensing method for the portable detection of a variety of biomarkers. Artificial biocatalysts can replace traditional natural enzymes in the fields of enzymatic colorimetric biodetection; however, the exploration of new biocatalysts with efficient, stable, and specific biosensing reactions has remained challenging so far. Here, to enhance the active sites and overcome the sluggish kinetics of metal sulfides, the creation of an amorphous RuS2 (a-RuS2 ) biocatalytic system is reported, which can dramatically boost the peroxidase-mimetic activity of RuS2 for the enzymatic detection of diverse biomolecules. Due to the existence of abundant accessible active sites and mildly surface oxidation, the a-RuS2 biocatalyst displays a twofold Vmax value and much higher reaction kinetics/turnover number (1.63 × 10-2 s-1 ) compared to that of the crystallized RuS2 . Noticeably, the a-RuS2 -based biosensor shows an extremely low detection limit of H2 O2 (3.25 × 10-6 m), l-cysteine (3.39 × 10-6 m), and glucose (9.84 × 10-6 m), respectively, thus showing superior detection sensitivity to many currently reported peroxidase-mimetic nanomaterials. This work offers a new path to create highly sensitive and specific colorimetric biosensors in detecting biomolecules and also provides valuable insights for engineering robust enzyme-like biocatalysts via amorphization-modulated design.

IrPd Nanoalloy-Structured Bifunctional Electrocatalyst for Efficient and pH-Universal Water Splitting.

The lack of high efficiency and pH-universal bifunctional electrocatalysts for water splitting to hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) hinders the large-scale production of green hydrogen. Here, an IrPd electrocatalyst supported on ketjenblack that exhibits outstanding bifunctional performance for both HER and OER at wide pH conditions is presented. The optimized IrPd catalyst exhibits a specific activity of 4.46 and 3.98 A mgIr -1 in the overpotential of 100 and 370 mV for HER and OER, respectively, in alkaline conditions. When applied to the anion exchange membrane electrolyzer, the Ir44 Pd56 /KB catalyst shows a stability of >20 h at a current of 250 mA cm-2 for water decomposition, indicating promising prospects for practical applications. Beyond offering an advanced electrocatalyst, this work also guides the rational design of desirable bifunctional electrocatalysts for HER and OER by regulating the microenvironments and electronic structures of metal catalytic sites for diverse catalysis.

Observation of black carbon in Northern China in winter of 2018-2020 and its implications for black carbon mitigation.

Enhanced observations of BC in hotspot regions with a high temporal resolution are critical to refining our BC mitigation strategies, which are co-directed by air-quality and climate goals. In this work, the temporal variation and emission sources of BC in Shijiazhuang, Northern China, during the winter of 2018-2020 were investigated on the basis of multi-wavelength Aethalometer BC observations. The average BC concentrations decreased from 9.13 ± 6.63 µg/m3 in the winter of 2018 to 3.51 ± 2.48 µg/m3 in the winter of 2020. The BC source attributions derived from the Aethalometer model showed that the BC concentrations in Shijiazhuang in the winter of 2018 were mainly contributed by biomass burning (53 %). In contrast, during the winter of 2019 and 2020, fossil fuel combustion (BCff) exhibited higher contributions, and higher BC concentrations attributed to greater BCff contributions. Potential source contribution function (PSCF) analysis suggested that local emissions in Shijiazhuang and transport from highly industrialized regions like central Shanxi and southern Hebei contributed significantly to BC in Shijiazhuang. Concentration weighted trajectory (CWT) analysis revealed that the BC contributions from source regions decreased successively from the winter of 2018 to the winter of 2020. Our results also implied an air quality/climate co-benefit effect of enforcing multi-scale air-quality improvement regulations. Yet, it is still worth noting that some of the measures in favor of reducing BC emissions contradict the measures for reducing CO2. The synergies of BC to air quality and climate should be considered and addressed by policymakers with the aim of realizing a sustainable environment.

Ir Cluster-Anchored MOFs as Peroxidase-Mimetic Nanoreactors for Diagnosing Hydrogen Peroxide-Related Biomarkers.

Exploring multifaceted and highly sensitive biosensors is a major challenge in biotechnology and medical diagnosis. Here, we create a new iridium (Ir) cluster-anchored metal-organic framework (MOF, namely, IrNCs@Ti-MOF via a coordination-assisted strategy) as a peroxidase (POD)-mimetic nanoreactor for colorimetrically diagnosing hydrogen peroxide-related biomarkers. Owing to the IrNCs-N/O coordination of Ti-MOF and unique enzymatic properties of Ir clusters, the IrNCs@Ti-MOF exhibits exceptional and exclusive POD-mimetic activities (Km = 3.94 mM, Vmax = 1.70 µM s-1, and turnover number = 39.64 × 10-3 s-1 for H2O2), thus demonstrating excellent POD-mimetic detecting activity and also super substrate selectivity, which is considerably more efficient than recently reported POD mimetics. Colorimetric studies disclose that this IrNCs@Ti-MOF-based nanoreactor shows multifaceted and efficient diagnosing activities and substrate selectivity, such as a limit of detection (LOD): 14.12 µM for H2O2 at a range of 0-900 µM, LOD: 3.41 µM for l-cysteine at a range of 0-50 µM, and LOD: 20.0 µM for glucose at a range of 0-600 µM, which enables an ultrasensitive and visual determination of abundant H2O2-related biomarkers. The proposed design will not only provide highly sensitive and cheap colorimetric biosensors in medical resource-limited areas but also offer a new path to engineering customizable enzyme-mimetic nanoreactors as a powerful tool for accurate and rapid diagnosis.

Evaluation of a Gaussian dispersion transformation technique for tomographic mapping of the concentration field of atmospheric chemicals using multi-path optical remote sensing.

Horizontal radial plume mapping is a cost-effective optical remote sensing method for sensitive mapping concentration distribution of atmospheric chemicals in real time. However, its sparse sampling poses challenges for reconstruction algorithms. Neither non-smooth nor smooth algorithms can recover the realistic plume shape. A new approach called Gaussian dispersion transformation (GDT) has been proposed. It first reconstructs the emission rates from unknown sources. Then concentrations are calculated through a transformation matrix defined by a Gaussian dispersion model. Smoothness regularization is also applied during the reconstruction. The method was evaluated by using randomly generated maps. It shows significant improvement over a reconstructed plume shape. The nearness shows 72%-117% better than the non-negative least-square (NNLS) algorithm and 15%-26% better than the low third derivative (LTD) algorithm. A controlled-release field experiment of methane was also conducted. The realistic concentration distribution was calculated by using a Lagrangian stochastic dispersion model. The GDT algorithm successfully recovered the realistic plume shape. The nearness shows approximately 16% better than the NNLS and the LTD algorithms. Finally, a sensitivity analysis shows that the wind direction and atmospheric stability are the main parameters that affect the performance of the GDT algorithm.

Catalase-Mimetic Artificial Biocatalysts with Ru Catalytic Centers for ROS Elimination and Stem-Cell Protection.

Exploring high-efficiency reactive oxygen species (ROS)-elimination materials is of great importance for combating oxidative stress in diverse diseases, especially stem-cell-based biotherapeutics. By mimicking the FeN active centers of natural catalase, here, an innovative concept to design ROS-elimination artificial biocatalysts with Ru catalytic centers for stem-cell protection is reported. The experimental studies and theoretical calculations have systematically disclosed the activity merits and structure diversities of different Ru sites when serving as ROS-elimination artificial biocatalysts. Benefiting from the metallic electronic structures and synergetic effects of multiple sites, the artificial biocatalysts with Ru cluster centers present exceptional ROS-elimination activity; notably, it shows much higher catalytic efficiency per Ru atom on decomposing H2 O2 when compared to the isolated single-atom Ru sites, which is more efficient than that of the natural antioxidants and recently reported state-of-the-art ROS-scavenging biocatalysts. The systematic stem-cell protection studies reveal that the catalase-like artificial biocatalysts can provide efficient rescue ability for survival, adhesion, and differentiation functions of human mesenchymal stem cells in high ROS level conditions. It is suggested that applying these artificial biocatalysts with Ru cluster centers will offer a new pathway for engineering high-performance ROS-scavenging materials in stem-cell-based therapeutics and many other ROS-related diseases.

A lanthanide nanocomposite with cross-relaxation enhanced near-infrared emissions as a ratiometric nanothermometer.

Lanthanide luminescence nanothermometers (LNTs) provide microscopic, highly sensitive, and visualizable optical signals for reporting temperature information, which is particularly useful in biomedicine to achieve precise diagnosis and therapy. However, LNTs with efficient emissions at the long-wavelength region of the second and the third near-infrared (NIR-II/III) biological window, which is more favourable for in vivo thermometry, are still limited. Herein, we present a lanthanide-doped nanocomposite with Tm3+ and Nd3+ ions as emitters working beyond 1200 nm to construct a dual ratiometric LNT. The cross-relaxation processes among lanthanide ions are employed to establish a strategy to enhance the NIR emissions of Tm3+ for bioimaging-based temperature detection in vivo. The dual ratiometric probes included in the nanocomposite have potential in monitoring the temperature difference and heat transfer at the nanoscale, which would be useful in modulating the heating operation more precisely during thermal therapy and other biomedical applications. This work not only provides a powerful tool for temperature sensing in vivo but also proposes a method to build high-efficiency NIR-II/III lanthanide luminescent nanomaterials for broader bio-applications.

On-road mileage-based emission factors of gaseous pollutants from bi-fuel taxi fleets in China: The influence of fuel type, vehicle speed, and accumulated mileage.

Urban taxis tend to be high mileage vehicles, and therefore potentially a significant contributor to local air pollution. To investigate the on-road emissions of gaseous air pollutants from urban taxi fleets, the mileage-based emission factors (EFs) for 20 gasoline/CNG bi-fuel taxis in China were measured using the in situ monitoring system. It was found that shifting the taxis' fuel from gasoline to CNG could cause significant emissions reduction in CO, slight drop in HC and small increase in NOx. With the fuel shift from China-VI gasoline to GB 18047-2017 CNG, approximately 82% reduction in CO, 14% reduction in HC and about 14% more NOx was observed. With fuel shift from China-III gasoline to GB 18047-2000 CNG, the reductions were 65%, 6% and 11%, respectively. When the China-VI gasoline-fueled taxis travel at higher speed (60 km/h or higher), the vehicles emit approxiamtly ten times more CO than that at lower speed (20-50 km/h). The mileage-based NOxEFs was strongly and positively related to the vehicles' speed for the taxis fueled by China-VI gasoline and GB 18047-2017 CNG. The ratio of NOx and HC emissions from gasoline-fueled taxis is lower than that from CNG-fueled taxis. Considerable reductions of the mileage-based EFs of CO, HC, and NOx from China-VI gasoline- and GB 18047-2017 CNG-fueled bi-fuel taxis were recorded. The taxi vehicles with higher accumulated mileage (greater than 200,000 km) were found with higher CO and HC emissions, due to the deterioration of vehicle engine performance and the exhaust catalyst system.

CoFe Alloy-Decorated Interlayer with a Synergistic Catalytic Effect Improves the Electrochemical Kinetics of Polysulfide Conversion.

Good electrical conductivity, strong catalytic activity, high interaction with lithium polysulfides (LIPSs), simple method, and low cost should be considered for the design and preparation of high-performance electrochemical catalysts that catalyze the conversion of LIPSs. In this work, we designed a bimetallic alloyed multifunctional interlayer with multiple adsorption/catalysis sites. The interwoven carbon fibers derived from bacterial cellulose (BC) not only contribute to reducing metal ions to metals but also confine the growth of Co-Fe alloys formed in situ. The metal supported on carbon is very effective for the conversion of LIPSs due to its high adsorption and catalytic sites. In addition, the synergistic effect between Fe and Co species leads to excellent bifunctional catalytic activity. Through detailed electrochemical analysis and theoretical calculations, we revealed that CoFe@CNFs has superior electrocatalytic activity, and the lithium-sulfur (Li-S) batteries with a catalytic interlayer can deliver satisfactory rate and cycle performance. At a high current density of 2C, the discharge capacity can still reach 627 mAh g-1. At a current density of 1C, the Coulombic efficiency is maintained at a level close to 100% during the whole cycle process and a satisfying low capacity decay of 0.08% per cycle. More importantly, even if the ambient temperature drops to 0 °C, the Li-S battery using the interlayer can still be charged and discharged normally and shows acceptable discharge capacity, which shows that it has good rate kinetics.

Directional control of the off-normal scattering from a single nanodisk by superposed linearly and radially polarized beams.

A scheme to dynamically control the off-axis directional scattering from a silicon nanodisk is proposed, which is based on focused fields formed by the coherent superposition of radially and linearly polarized beams. When the phase condition of the generalized Kerker conditions is satisfied at a specified wavelength, the amplitude requirement for the off-axis directional scattering along a required direction can be fulfilled by tuning the magnitude ratio of the two focused beams. Therefore, directional control of the off-axis scattering in the meridional plane is achieved without the manipulation of the working wavelength. Our findings provide new possibilities of future potential applications of all-dielectric nanoantennas.

Mo2C Electrocatalysts for Kinetically Boosting Polysulfide Conversion in Quasi-Solid-State Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) suffer from sluggish reaction kinetics of sulfur-containing species and loss of soluble polysulfides (PSs) during cycling, especially in the case of liquid electrolytes. Here, we improve the kinetics of sulfur species by decorating Mo2C nanoparticles on carbon nanotubes (CNTs) as the host for sulfur active mass. In addition, by use of gel polymer electrolytes (GPEs) derived from in situ polymerization of 1,3-dioxolane (DOL) to mitigate the diffusion of PSs and improve the stability of Li stripping/plating. As a result, the sulfur cathodes are endowed with enhanced initial specific capacity and suppressed dissolution of sulfur species. The cells with CNT/Mo2C/S cathodes and GPE exhibit excellent electrochemical performance. The anodes cycled with GPE show remarkably enhanced lithium plating-stripping behavior. Benefitting from the synergistic effect, LSBs with higher energy density and improved durability are obtained, demonstrating a new approach for developing high-performance quasi-solid-state Li metal batteries.

Cancer risk assessment for exposure to hazardous volatile organic compounds in Calgary, Canada.

Oil and natural gas (O&G) extraction operations emit hazardous volatile organic compounds (VOCs) in quantities that have adverse effects on human health. Our current understanding of the exposure risks associated with upstream O&G exploitations remains limited, and very few quantitative on-site remediation strategies have been proposed. To this end, we assessed the health risks associated with the emission of hazardous VOCs and presented a set of remediation goals for the city of Calgary, which is a major center of the Canadian oil industry. Results from probabilistic risk assessment (PRA) suggested that although VOCs had a negligible impact on chronic non-cancer-associated risk, inhalation-associated cancer risk remained a significant concern. Carbon tetrachloride, benzene, and 1,3-butadiene were the dominant VOCs, representing 88% of the integrated inhalation cancer risk (= 7.8 × 10-5); background, solid fuel combustion, and O&G extraction were among the primary sources that posed the greatest threat to human health. Results of a Monte Carlo simulation revealed that the probability of developing cancer due to inhalation of hazardous VOCs was ∼13.1% on clean air days and 45.9% on days with significant levels of air pollution. Preliminary remediation goals (PRGs) included reductions of 24.2-65.1% and 11.4-50.9% targeting priority VOCs and their sources, respectively. Taken together, our findings suggest that stringent control of the sources of VOCs, particularly fossil fuel combustion, is an urgent priority. PRA coupled with PRGs provides informative risk assessments and suggests quantitative remediation strategies that can be applied toward improved management of hazardous pollutants.

Sharper photonic nanojets generated by microspheres under higher-order radially polarized beam illumination.

Photonic nanojets (PNJs) generated from a single microsphere illuminated by higher-order radially polarized (RP) beams are investigated. The effects of the size parameters of higher-order RP beams, the refractive index, and radius of the dielectric microsphere on the full width at half-maximum and peak intensity of the PNJ are numerically discussed and qualitatively interpreted. The results show that the minimal width of the PNJ can be obtained by optimally adjusting the size parameter. The PNJ beam waist becomes gradually narrower with increasing the radial mode number. As compared to the case of plane wave illumination, sharper PNJs are more easily generated when irradiated by a higher-order RP beam, even for microspheres with lower refractive indices or larger radii. Our findings can promote potential applications of PNJs in a variety of fields including super-resolution microscopy, nanolithography, and optical data storage.

Extraction of Lithium from Single-Crystalline Lithium Manganese Oxide Nanotubes Using Ammonium Peroxodisulfate.

In this work, a spinel single-crystalline Li1.1Mn1.9O4 has been successfully synthesized using ß-MnO2 nanotubes as the self-sacrifice template. The tubular morphology was retained through solid-state reactions, attributed to a minimal structural reorganization from tetragonal ß-MnO2 to spinel Li1.1Mn1.9O4. The materials were investigated as sorbents for lithium recovery from LiCl solutions, recycled using H2SO4 and (NH4)2S2O8. Li1.1Mn1.9O4 nanotubes exhibited favorable lithium extraction behavior due to tubular nanostructure, single-crystalline nature, and high crystallinity. (NH4)2S2O8 eluent ensures the structural stability of Li1.1Mn1.9O4 nanotube, registering a Li+ adsorption capacity of 39.21 mg g-1 (∼89.73% of the theoretical capacity) with only 0.08% manganese dissolution after eight adsorption/desorption cycles, compared to that of 1.21% for H2SO4. It reveals the degradation of sorbent involves with the volume change, Mn reduction, and Li/Mn ratio depletion. New strategies, based on nanotube adsorbent and (NH4)2S2O8 eluent, can extract lithium ions at satisfactorily high degrees while effectively minimizing manganese dissolution.