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Abstract Multidrug resistance presents an obstacle in cancer treatment. Among numerous combative strategies, collateral sensitivity (CS) drugs have opened a new avenue to defeat cancer by exploiting selective toxicity against multidrug-resistant (MDR) cancer. In the present study, a clinically used synthetic steroid hormone, danazol, was investigated for its CS properties and cytotoxic mechanisms. Compared with natural hormones, danazol possessed a stronger selective cytotoxicity against MDR cancer cells. Danazol induced the arrest of MDR cancer cells at the G2/M phase and caspase-8–related early apoptosis. Furthermore, in MDR cancer cells, danazol reduced STAT3 phosphorylation as well as the expression of STAT3-regulated genes involved in cell survival, such as c-Myc, CDC25, and CDK1. Danazol also upregulated the cell cycle inhibitor p21 in MDR cancer cells. Supporting the experimental results, docking studies have revealed that danazol can likely bind favourably with STAT3. Taken together, our results suggest that danazol exerts a CS effect by inhibiting the STAT3 pathway in MDR cancer cells and thus provides a possible solution for MDR cancers.

Tree peony is a famous ornamental plant in the world. However, little is known about the leaf color mutants in tree peony. The present study monitored the physiological and photosynthetic properties of a yellow leaf mutant (yl1) in tree peony. The results showed that the yl1 mutant had lower pigment contents, but increased chlorophyll (Chl) a/b and carotenoids to Chl ratio. Microstructure and ultrastructure analysis showed that the yl1 mutant had smaller chloroplasts, few thylakoid stacks, and a few stroma thylakoid membranes remained along with clusters of osmiophilic granules, which might result from inhibition at the reactions from coproporphyrinogen III to protoporphyrin IX. The yl1 mutant had lower leaf net photosynthetic rate, stomatal conductance, transpiration rate, and stomata limitation value, but higher intercellular CO2 concentration. Analysis of simple sequence repeat markers indicated that four pairs of primers could obtain different bands in the genome of the yl1 mutant compared to the wild type.

Evaporation plays a key role in applications such as cooling and desalination. Here, the authors experimentally demonstrated a unifying relationship between dimensionless flux and driving potential for evaporation kinetics under different working conditions.

In the summer of 2017, measurements of ozone (O3) and its precursors were carried out at an urban site in Jinan, a central city in the North China Plain (NCP). A continuous O3 pollution event was captured during 4–11 August, with the maximum hourly O3 mixing ratio reaching 154.1 ppbv. Model simulation indicated that local photochemical formation and regional transport contributed 14.0±2.3 and 18.7±4.0 ppbv h−1, respectively, to the increase in O3 during 09:00–15:00 LT (local time) in this event. For local O3 formation, the calculated OH reactivities of volatile organic compounds (VOCs) and carbon monoxide (CO) were comparable between O3 episodes and non-episodes (p>0.05), so was the OH reactivity of nitrogen oxides (NOx). However, the ratio of OH reactivity of VOCs and CO to that of NOx increased from 2.0±0.4 s−1 s1 during non-episodes to 3.7±0.7 s−1 s1 during O3 episodes, which resulted in the change in the O3 formation mechanism from the VOC-limited regime before the O3 pollution event to the transitional regime during the event. Correspondingly, the simulated local O3 production rate during the event (maximum: 21.3 ppbv h−1) was markedly higher than that before the event (p) (maximum: 16.9 ppbv h−1). Given that gasoline and diesel exhaust made large contributions to the abundance of O3 precursors and the O3 production rate, constraint on vehicular emissions is the most effective strategy to control O3 pollution in Jinan. The NCP has been confirmed as a source region of tropospheric O3, where the shift in regimes controlling O3 formation like the case presented in this study can be expected across the entire region, due to the substantial reductions of NOx emissions in recent years.

The continent-to-ocean supply of phosphorus (P) in the soluble state, recognized as bioavailable P, via the atmosphere is hypothesized to be crucial to the biological cycle in offshore surface seawater. To investigate the solubility of P in aerosol particles moving towards the northwestern Pacific from the Asian continent, we measured the total P (TP), total dissolved P (TDP) and dissolved inorganic P (DIP) in aerosols at Qingdao (36∘06′ N, 120∘33′ E), a coastal city in eastern China. The samples were collected in December 2012 and January 2013 (winter) and in March and April 2013 (spring), when the middle-latitude westerly wind was prevailing. On average, P solubility, i.e., the ratio of TDP to TP, was 32.9±16.7 % in winter and 21.3±9.8 % in spring, and the TP concentrations in the two seasons were similar. This seasonal solubility difference is attributed to the aerosol sources containing the P. Particles in winter were predominantly anthropogenic particles from local and regional areas, and particles in spring were significantly influenced by natural dust from the arid and semiarid areas in the inland part of the continent. Moreover, acidification processes associated with the formation of sulfate and nitrate in the winter samples enhanced P solubility, suggesting that the P in anthropogenic particles was more susceptible to the production of acidic species than that in natural dust particles. There was a strong positive correlation between P solubility and relative humidity (RH). P solubility was usually less than 30 % when RH was below 60 %, even when the content of acidic species and/or anthropogenic particles in the aerosols was high, suggesting humidity had a critical role in the production of TDP. In addition, the proportion of DIP in TDP was high when the particles were predominantly anthropogenic, and the proportion of dissolved organic P (DOP; quantified as TDP minus DIP) in TDP was high when the particles were dominated by natural dust. These results indicate that, as the contents of bioavailable P in Asian continent outflows are closely dependent on the aerosol particle origins, atmospheric acidic processes could convert P into a bioavailable state under certain meteorological conditions. Therefore, the recent severe air pollution over East Asia might have enhanced the input of bioavailable P to downwind marine areas.

Spalling is one of the main defects of hybrid ceramic bearings, and the localization of the spalling is hard to realize based on traditional vibration signals. This paper proposes a new localization method for spalling on the outer ring of hybrid ceramic ball bearings based on the characteristics in the sound radiation signals. The dynamic model containing the spalling is presented, and the sound radiation is obtained through the sub-source decomposition method. Cases when the spallings are located in different zones on the outer ring are studied, and the circumferential distribution of the sound radiation is analyzed in time domain and frequency domain. The localization accuracy with different indicators are compared as well as the recognition clarity, and the results are verified through experimental investigations. Results show that the spalling makes great impact on the sound radiation of the hybrid ceramic ball bearing, and the circumferential and radial distribution of the sound radiation is closely related with the location of the spalling. It is quite essential to acquire the changes of the frequency components in the sound radiation, and the radial attenuation of the amplitude of the spalling-related frequency is crucial for the accurate localization of the spalling.

Ageing is associated with reduced endothelium-derived nitric oxide (NO) production in the femoral artery of Sprague Dawley (SD) rats. In the current study, we examined endothelium-dependent relaxation (EDR) in the saphenous artery and its caudal branches. We used acetylcholine and the Proteinase-Activated receptor-2 (PAR2)-specific agonist (2fLIGRLO) with nitroarginine methylester (L-NAME) to assess EDR in two groups of male SD rats (age in weeks: young, 10–12; old, 27–29). Acetylcholine and 2fLIGRLO were potent NO-dependent relaxant agents in all arteries. For all arteries, EDR by acetylcholine decreased significantly in old compared to young SD rats. Interestingly, PAR2-induced EDR of proximal saphenous artery segments and caudal branches decreased significantly in old compared to young, but did not differ for the in-between middle and distal ends of the saphenous artery. L-NAME treatment increased subsequent contractions of proximal and middle segments of saphenous arteries by phenylephrine and U46619 in young, but not in old, SD rats. We conclude the SD saphenous artery and caudal branches exhibit regional characteristics that differ in response to specific EDR agonists, endothelial NO synthase inhibitor, and changes to endothelium function with increased age, which are, in part, attributed to decreased sensitivity of vascular smooth muscle to the gaseous transmitter NO.

The interaction of particles with the chamber walls has been a significant source of uncertainty when analyzing results of secondary organic aerosol (SOA) formation experiments performed in Teflon chambers. A number of particle wall-loss correction methods have been proposed including the use of a size-independent loss rate constant, the ratio of suspended organic mass to that of a conserved tracer (e.g., sulfate seeds), and a size-dependent loss rate constant, etc. For complex experiments such as the chemical aging of SOA, the results of the SOA quantification analysis can be quite sensitive to the adopted correction method due to the evolution of the particle size distribution and the duration of these experiments. We evaluated the performance of several particle wall-loss correction methods for aging experiments of α-pinene ozonolysis products. Determining the loss rates from seed loss periods is necessary for this system because it is not clear when chemical reactions have been completed. Results from the OA ∕ sulfate ratio and the size-independent correction methods can be influenced significantly by the size dependence of the particle wall-loss process. Coagulation can also affect the particle size distribution, especially for particles with diameter less than 100 nm, thus introducing errors in the results of the wall-loss correction. The corresponding loss rate constants may vary from experiment to experiment, and even during a specific experiment. Friction between the Teflon chamber walls and non-conductive surfaces can significantly increase particle wall-loss rates and the chamber may require weeks to recover to its original condition. Experimental procedures are proposed for the characterization of particle losses during different stages of these experiments and the evaluation of corresponding particle wall-loss correction.

The production cross sections for primary and residual fragments produced in two reaction systems 136Xe + 198Pt and 238U + 198Pt at incident energy 8 MeV/nucleon are calculated by improved quantum molecular dynamics (ImQMD) model incorporated with the statistical evaporation model (HIVAP code). It is found that the cross sections for n-rich N=126 residual fragments are several times larger in 238U+198Pt than in 136Xe+198Pt due to the larger cross sections and lower excitation energies of primary fragments in 238U induced reactions. In both systems, N=126 semi-magic residues are produced via neutron emission in the decay of primary fragments, which survive in the semi-central collisions and have lower excitation energies.

Abstract Stimuli‐responsive materials have been lately employed in soft robotics enabling new classes of robots that can emulate biological systems. The untethered operation of soft materials with high power light, magnetic field, and electric field has been previously demonstrated. While electric and magnetic fields can be stimulants for untethered actuation, their rapid decay as a function of distance limits their efficacy for long‐range operations. In contrast, light—in the form of sunlight or collimated from an artificial source (e.g., laser, Xenon lamps)—does not decay rapidly, making it suitable for long‐range excitation of untethered soft robots. In this work, an approach to harnessing sunlight for the untethered operation of soft robots is presented. By employing a selective solar absorber film and a low‐boiling point (34 °C) fluid, light‐operated soft robotic grippers are demonstrated, grasping and lifting objects almost 25 times the mass of the fluid in a controllable fashion. The method addresses one of the salient challenges in the field of untethered soft robotics. It precludes the use of bulky peripheral components (e.g., compressors, valves, or pressurized gas tank) and enables the untethered long‐range operation of soft robots.

Castration-resistant prostate cancer (CRPC) threatens the health of men in general and no effective therapeutics currently exists for the treatment of CRPC. It is therefore of great importance to find a novel molecule that can be a biomarker and a therapeutic target for CRPC. First, we found that the serum fibrinogen gamma (FGG) levels in patients with CRPC were significantly higher than those with localized prostate cancer (PCa) through iTRAQ proteomics and ELISA experiments. Immunohistochemistry, quantitative real-time polymerase chain reaction and western blot also showed an increase of FGG expression in CRPC tissues and cells. Then we proved the proliferation, invasion and migration ability of CRPC cells were significantly reduced after FGG knockdown. The number of apoptotic cells increased at least sixfold after FGG silencing, and was observed in conjunction with an upregulation of p53, caspase 3, clea-caspase 3, and Bax, and a downregulation of Bcl2 and survivin. FGG knockdown in DU145 cells resulted in smaller xenografts than control cells in a mouse model. and we established that FGG is modulated by IL-6 which was increased in CRPC patients via phosphorylation of STAT3. The data suggests that FGG may be a potential therapeutic target and prognostic marker for CRPC.

Two-dimensional (2D) transition metal dichalcogenides (TMDC) have attracted great research interest due to their potential application in electronics, optoelectronics, electrocatalysis, and so on. To satisfy expectations, high-quality materials with designed structures are highly desired through the controlled growth of TMDC. Chemical vapor deposition (CVD) offers facile control in synthesizing 2D TMDC as well as a high degree of freedom for tuning their structures and properties. In this review, we elaborate on recent advances in CVD techniques for synthesizing atomically thin TMDC. The novel techniques for achieving continuous uniform 2D films are provided along with insights into the growth mechanisms. Moreover, approaches toward high-quality materials by growing large single crystals and oriented domains are thoroughly summarized. The strategies for controlling the crystal thickness, phase, and doping condition are also discussed. Finally, we address the challenges in the field and prospective research directions.

Although numerous reports have elucidated the neurotoxic impacts of Ti-6Al-4V (Ti64) due to the presence of vanadium, it is the most widely used biomedical Ti material. This is because it exhibits significantly better mechanical performance characteristics than those of pure Ti. In addition to the possibility of facilitating the production of customized medicines, selective laser melting (SLM) additive manufacturing (AM) can enable pure Ti to match the properties of Ti64 by utilizing several mechanisms such as grain refinement and solid solution strengthening. These results can be obtained due to the high cooling rate of the AM process and via a possible modification in the alloy chemistry of Ti. Herein, we report a novel approach that endows the pure Ti prepared via AM with excellent mechanical properties (ultimate tensile strength, yield strength, elongation, and microhardness of 1057.05 MPa, 784.59 MPa, 24.09%, and 307 Hv, respectively), corrosion resistance, and biocompatibility, while significantly reducing the cost of the powder. The pure Ti material developed in this study has significant potential for use as an advanced biomedical material in a variety of applications such as dental and bone structure replacement. Furthermore, it can act as a low-cost alternative to biomedical materials such as Ti-6Al-4V.

Abstract Environmental scanning electron microscopy (ESEM) is a powerful technique that enables imaging of diverse specimens (e.g., biomaterials, chemical materials, nanomaterials) in a hydrated or native state while simultaneously maintaining micro‐to‐nanoscale resolution. However, it is difficult to achieve high signal‐to‐noise and artifact‐free secondary electron images in a high‐pressure gaseous environment due to the intensive electron‐gas collisions. In addition, nanotextured substrates can mask the signal from a weakly scattering sample. These drawbacks limit the study of material dynamics under extreme conditions and correspondingly our understanding in many fields. In this work, an imaging framework called Quasi‐Newtonian ESEM is proposed, which introduces the concepts of quasi‐force and quasi‐work by referencing the scattering force in light–matter interactions, to break these barriers without any hardware changes. It is shown that quasi‐force is a more fundamental quantity that has a more significant connection with the sample morphology than intensity in the strongly scattering regime. Experimental and theoretical studies on the dynamics of droplet condensation in a high‐pressure environment (up to 2500 Pa) successfully demonstrate the effectiveness and robustness of the framework and that the overwhelmed signal of interest in ESEM images can be reconstructed through information stored in the time domain, i.e., frames captured at different moments.

Improved insight into the molecular mechanisms of head and neck squamous cell carcinoma (HNSCC) is required to predict prognosis and develop a new therapeutic strategy for targeted genes. The aim of this study is to identify significant genes associated with HNSCC and to further analyze its prognostic significance. In our study, the cancer genome atlas (TCGA) HNSCC database and the gene expression profiles of GSE6631 from the Gene Expression Omnibus (GEO) were used to explore the differential co-expression genes in HNSCC compared with normal tissues. A total of 29 differential co-expression genes were screened out by Weighted Gene Co-expression Network Analysis (WGCNA) and differential gene expression analysis methods. As suggested in functional annotation analysis using the R clusterProfiler package, these genes were mainly enriched in epidermis development and differentiation (biological process), apical plasma membrane and cell-cell junction (cellular component), and enzyme inhibitor activity (molecular function). Furthermore, in a protein-protein interaction (PPI) network containing 21 nodes and 25 edges, the ten hub genes (S100A8, S100A9, IL1RN, CSTA, ANXA1, KRT4, TGM3, SCEL, PPL, and PSCA) were identified using the CytoHubba plugin of Cytoscape. The expression of the ten hub genes were all downregulated in HNSCC tissues compared with normal tissues. Based on survival analysis, the lower expression of CSTA was associated with worse overall survival (OS) in patients with HNSCC. Finally, the protein level of CSTA, which was validated by the Human Protein Atlas (HPA) database, was down-regulated consistently with mRNA levels in head and neck cancer samples. In summary, our study demonstrated that a survival-related gene is highly correlated with head and neck cancer development. Thus, CSTA may play important roles in the progression of head and neck cancer and serve as a potential biomarker for future diagnosis and treatment.

Nuclear dissipation retards fission. Using the stochastic Langevin model, we study pre- and post-saddle emitted neutrons, protons and α particles of heavy 245Cf nuclei as a function of the postsaddle dissipation strength (β) in the absence and presence of backstreaming around the saddle point. It is shown that the backstreaming effects (BEs) cause the fissioning system to return back inside saddle, which increases presaddle light particles but decreases postsaddle emission. Moreover, the BEs on pre- and post-saddle evaporation are found to become greater with increasing β and excitation energy. These findings demonstrate a significant role of BEs in tightly constraining the postsaddle dissipation strength with light particle multiplicity. Furthermore, we analyze the measured prescission neutron number in the reaction 16O (Elab=104 MeV) +232Th ⟶248Cf, and find that, after accounting for the BEs, the best-fit value of the β required to satisfactorily describe the experimental data changes from 9.6 ×1021 s−1 to 6×1021 s−1, showing a strong influence of backstreaming on accurately probing the postsaddle dissipation strength. Keywords: Nuclear dissipation, Light particle emission, Backstreaming effects, Langevin model

Passive daytime radiative cooling presents a promising low-cost refrigeration solution but has thus far relied on specialized nanophotonic structures. Here Bhatia et al. show a directional approach that decouples solar reflectance and infrared emission to achieve superior cooling performance.

To investigate the timing of deposition and provenance of early Mesozoic strata in the northeastern North China Craton (NCC) and to understand the early Mesozoic paleotectonic evolution of the region, we combine stratigraphy, U–Pb zircon geochronology, and Hf isotopic analyses. Early Mesozoic strata include the Early Triassic Heisonggou, Late Triassic Changbai and Xiaoyingzi, and Early Jurassic Yihe formations. Detrital zircons in the Heisonggou Formation yield ∼ 58 % Neoarchean to Paleoproterozoic ages and ∼ 42 % Phanerozoic ages and were sourced from areas to the south and north of the basins within the NCC, respectively. This indicates that Early Triassic deposition was controlled primarily by the southward subduction of the Paleo-Asian oceanic plate beneath the NCC and collision between the NCC and the Yangtze Craton (YC). Approximately 88 % of the sediments within the Late Triassic Xiaoyingzi Formation were sourced from the NCC to the south, with the remaining ∼ 12 % from the Xing'an–Mongolia Orogenic Belt (XMOB) to the north. This implies that Late Triassic deposition was related to the final closure of the Paleo-Asian Ocean during the Middle Triassic and the rapid exhumation of the Su–Lu Orogenic Belt between the NCC and YC. In contrast, ∼ 88 % of sediments within the Early Jurassic Yihe Formation were sourced from the XMOB to the north, with the remaining ∼ 12 % from the NCC to the south. We therefore infer that rapid uplift of the XMOB and the onset of the subduction of the Paleo-Pacific Plate beneath Eurasia occurred in the Early Jurassic.

Fume hoods in laboratories consume the energy equivalent of up to four American households per hood; however, closing a modern hood’s sash completely can save up to 75% of that energy. Past efforts have attempted to harness this potential energy reduction by reminding users to close the sash when a hood is not in use. In this work, we developed a device to measure the efficacy of these energy-saving methods. The device records the position of the sash and detects motion to determine whether a user is present, and, when fitted with a piezoelectric buzzer, can audibly alert users to close the sash when not in use. We installed this device in laboratories to quantify the energy and cost savings resulting from real-time audible feedback and found that the alarm reduced wasted energy by 87 to 98%. In addition, the platform demonstrated here can be used to quantitatively test other energy-saving methods that rely on user behavioral change in future work. Keywords: Energy savings, Behavioral modification, Active feedback, Motion detection

Simultaneous measurements of aerosol hygroscopicity and particle-phase chemical composition were performed at a suburban site over the Pearl River Delta region in the late summer of 2016 using a self-assembled hygroscopic tandem differential mobility analyzer (HTDMA) and an Aerodyne quadruple aerosol chemical speciation monitor (ACSM), respectively. The hygroscopic growth factor (HGF) of the Aitken mode (30 nm, 60 nm) and accumulation mode (100 nm, 145 nm) particles were obtained under 90 % relative humidity (RH). An external mixture was observed for particles of every size during this study, with a dominant mode of more-hygroscopic (MH) particles, as aged aerosols dominated due to the anthropogenic influence. The HGF of less-hygroscopic (LH) mode particles increased, while their number fractions decreased during the daytime due to a reduced degree of external mixing that probably resulted from the condensation of gaseous species. These LH mode particles in the early morning or late afternoon could be possibly dominated by carbonaceous material emitted from local automobile exhaust during rush hours. During polluted days with air masses flowing mainly from the coastal areas, the chemical composition of aerosols had a clear diurnal variation and a strong correlation with the mean HGF. Closure analysis was carried out between the HTDMA-measured HGF and the ACSM-derived hygroscopicity using various approximations for the hygroscopic growth factor of organic compounds (HGForg). Considering the assumptions regarding the differences in the mass fraction of each component between PM1 and 145 nm particles, the hygroscopicity-composition closure was achieved using an HGForg of 1.26 for the organic material in the 145 nm particles and a simple linear relationship between the HGForg and the oxidation level inferred from the O : C ratio of the organic material was suggested. Compared with the results from other environments, HGForg obtained from our measurements appeared to be less sensitive to the variation of its oxidation level, which is, however, similar to the observations in the urban atmosphere of other megacities in China. This finding suggests that the anthropogenic precursors or the photooxidation mechanisms might differ significantly between the suburban and urban atmosphere in China and those in other background environments. This may lead to different characteristics of the oxidation products in secondary organic aerosols (SOA) and therefore to a different relationship between the HGForg and its O : C ratio.

A positive bias at heights between 3 and 8 km has been observed when comparing the radio-occultation (RO)-retrieved refractivity with that of meteorological analyses and reanalyses in cases where heavy precipitation is present. The effect of precipitation in RO retrievals has been investigated as a potential cause of the bias, using precipitation measurements interpolated into the actual three-dimensional RO ray paths to calculate the excess phase induced by precipitation. The study consisted of comparing the retrievals when such extra delay is removed from the actual measurement and when it is not. The results show how precipitation itself is not the cause of the positive bias. Instead, we show that the positive bias is linked to high specific-humidity conditions regardless of precipitation. This study also shows a regional dependence of the bias. Furthermore, different analyses and reanalyses show a disagreement under high specific-humidity conditions and, in consequence, heavy precipitation.

Precisely controlled growth of oxide interfaces at the atomic layer level is critical for device applications but quite challenging. Here Sun et al. show real time monitoring and control of the surface composition of epitaxial strontium titanate perovskite films by analysing the Kikuchi lines.

Chinese high -resolution (HR) remote sensing satellites have made huge leap in the past decade. Commercial satellite datasets, such as GF-1, GF-2 and ZY-3 images, the panchromatic images (PAN) resolution of them are 2 m, 1 m and 2.1 m and the multispectral images (MS) resolution are 8 m, 4 m, 5.8 m respectively have been emerged in recent years. Chinese HR satellite imagery has been free downloaded for public welfare purposes using. Local government began to employ more professional technician to improve traditional land management technology. This paper focused on analysing the actual requirements of the applications in government land law enforcement in Guangxi Autonomous Region. 66 counties in Guangxi Autonomous Region were selected for illegal land utilization spot extraction with fusion Chinese HR images. The procedure contains: A. Defines illegal land utilization spot type. B. Data collection, GF-1, GF-2, and ZY-3 datasets were acquired in the first half year of 2016 and other auxiliary data were collected in 2015. C. Batch process, HR images were collected for batch preprocessing through ENVI/IDL tool. D. Illegal land utilization spot extraction by visual interpretation. E. Obtaining attribute data with ArcGIS Geoprocessor (GP) model. F. Thematic mapping and surveying. Through analysing 42 counties results, law enforcement officials found 1092 illegal land using spots and 16 suspicious illegal mining spots. The results show that Chinese HR satellite images have great potential for feature information extraction and the processing procedure appears robust.

Passive microwave sensors have the capability to provide information on snow depth (SD), which is critically important for hydrological modeling and water resource management. However, the different algorithms used to produce SD products lead to discrepancies in the data. To determine which products might be most suitable for Northern China, this paper assesses the accuracy of the existing snow depth products in the period of 2002–2011. By comparing three daily snow depth products, including NSIDC, WESTDC and ESA Globsnow, with snow cover product and meteorological stations data, the accuracies of the different SD products are analyzed for different snow class and forest cover fraction. The results show that comparison between snow cover derived from snow depth of NSIDC, ESA GlobSnow and WESTDC with snow cover product shows that accuracy of WESTDC and ESA GlobSnow in snow cover detecting can reach 0.70. Compared to meteorological stations data below 20 cm, NSIDC consistently overestimate, WESTDC and ESA Globsnow underestimate, furthermore the product from WESTDC is superior to the others. The three products have the same tendency of significant undervaluation over 20 cm. The WESTDC is superior to the ESA Globsnow and NSIDC in non-forest regions, whereas the ESA GlobSnow estimate is superior to the WESTDC and NSIDC in forest regions. As for the prairie and alpine snow, WESTDC has smaller bias and RMSE, meanwhile Globsnow has advantages in the snow depth retrieval in tundra and taiga snow. Therefore, we should choose the more suitable snow depth products according to different needs.

Harvesting water from the atmosphere is an important solution to water scarcity, but doing so in arid climates is highly challenging. Here, the authors develop a metal-organic framework-based water harvesting device that can deliver over 0.25 L of water per kg of adsorbent over a single cycle at relative humidities of 10–40% and at subzero dew points.

Secondary organic aerosol (SOA) formation from volatile organic compounds (VOCs) in the atmosphere can be thought of as a succession of oxidation steps. The production of later-generation SOA via continued oxidation of the first-generation products is defined as chemical aging. This study investigates aging in the α-pinene ozonolysis system with hydroxyl radicals (OH) through smog chamber experiments. The first-generation α-pinene ozonolysis products were allowed to react further with OH formed via HONO photolysis. After an equivalent of 2–4 days of typical atmospheric oxidation conditions, homogeneous OH oxidation of the α-pinene ozonolysis products resulted in a 20–40 % net increase in the SOA for the experimental conditions used in this work. A more oxygenated product distribution was observed after aging based on the increase in aerosol atomic oxygen-to-carbon ratio (O : C) by up to 0.04. Experiments performed at intermediate relative humidity (RH) of 50 % showed no significant difference in additional SOA formation during aging compared to those performed at a low RH of less than 20 %.

Airborne radio occultation (ARO) measurements collected during a ferry flight at the end of the PRE-Depression Investigation of Cloud-systems in the Tropics (PREDICT) field campaign from the Virgin Islands to Colorado are analyzed. The large contrast in atmospheric conditions along the flight path from the warm and moist Caribbean Sea to the much drier and cooler continental conditions provides a unique opportunity to address the sensitivity of ARO measurements to the tropospheric temperature and moisture changes. This long flight at nearly constant altitude (∼ 13 km) provided an optimal configuration for simultaneous high-quality ARO measurements from two high-gain side-looking antennas, as well as one relatively lower gain zenith (top) antenna. The omnidirectional top antenna has the advantage of tracking robustly more occulting satellites in all direction as compared to the limited-azimuth tracking of the side-looking antennas. Two well-adapted radio-holographic bending angle retrieval methods, full-spectrum inversion (FSI) and phase matching (PM), were compared with the standard geometric-optics (GO) retrieval method. Comparison of the ARO retrievals from the top antenna with the near-coincident ECMWF reanalysis-interim (ERA-I) profiles shows only a small root-mean-square (RMS) refractivity difference of ∼ 0.3 % in the drier upper troposphere from ∼ 5 to ∼ 11.5 km over both land and ocean. Both the FSI and PM methods improve the ARO retrievals in the moist lower troposphere and reduce the negative bias found in the GO retrieval due to atmospheric multipath. In the lowest layer of the troposphere, the ARO refractivity derived using FSI shows a negative bias of about −2 %. The increase of the refractivity bias occurs below 5 km over the ocean and below 3.5 km over land, corresponding to the approximate altitude of large vertical moisture gradients above the ocean and land surface, respectively. In comparisons to radiosondes, the FSI ARO soundings capture well the height of layers with sharp refractivity gradients but display a negative refractivity bias inside the boundary layer. The unique opportunity to make simultaneous independent recordings of occultation events from multiple antennas establishes that high-precision ARO measurements can be achieved corresponding to an RMS difference better than 0.2 % in refractivity (or ∼ 0.4 K). The surprisingly good quality of recordings from a very simple zenith antenna increases the feasibility of developing an operational tropospheric sounding system onboard commercial aircraft in the future, which could provide a large number of data for direct assimilation in numerical weather prediction models.

We demonstrate a Fabry-Perot interferometer with inner air-cavity for ultrasensitive strain measurement. The device is fabricated by fusion splicing of two sections of etched multimode fiber with offset. By selecting the appropriate value of the offset, the strain sensitivity can be greatly increased. In the case of introducing two-dimensional offset, the strain sensitivity can be increased by more than 4.5 pm/με when compared with that without offset. The device is simple in fabrication, robust in structure, economic in cost, and convenient in operation, and has high potential in many strain sensing applications.

Global Navigation Satellite System (GNSS) radio occultation (RO) measurements are promising in sensing the vertical structure of the Earth's planetary boundary layer (PBL). However, large refractivity changes near the top of PBL can cause ducting and lead to a negative bias in the retrieved refractivity within the PBL (below ∼ 2 km). To remove the bias, a reconstruction method with assumption of linear structure inside the ducting layer models has been proposed by Xie et al. (2006). While the negative bias can be reduced drastically as demonstrated in the simulation, the lack of high-quality surface refractivity constraint makes its application to real RO data difficult. In this paper, we use the widely available precipitable water (PW) satellite observation as the external constraint for the bias correction. A new framework is proposed to incorporate optimization into the RO reconstruction retrievals in the presence of ducting conditions. The new method uses optimal estimation to select the best refractivity solution whose PW and PBL height best match the externally retrieved PW and the known a priori states, respectively. The near-coincident PW retrievals from AMSR-E microwave radiometer instruments are used as an external observational constraint. This new reconstruction method is tested on both the simulated GNSS-RO profiles and the actual GNSS-RO data. Our results show that the proposed method can greatly reduce the negative refractivity bias when compared to the traditional Abel inversion.