Using TiO2 to capture hot electrons for self-powered position-sensitive photodetection.

As environmental issues arise, the demand for self-powered position-sensitive detectors (PSDs) is increasing because of their advantages in miniaturization and low power consumption. Finding higher efficiency schemes for energy conversion is paramount for realizing high-performance self-powered PSDs. Here, a surface plasmon-based approach was used to improve the energy conversion efficiency, and a plasmon-enhanced lateral photovoltaic effect (LPE) was observed in PSD with TiO2/Au nanorods (NRs)/Si structure. The Au NRs convert absorbed light energy into electricity by generating hot electrons, which are efficiently captured by the TiO2 layer, and the PSD is capable of generating position sensitivity as high as 251.75 mV/mm when illuminated by a 780 nm laser without any external power supply, i.e. about five times higher than similar sensors in previous studies. In addition, the position sensitivity can be tailored by the thickness of TiO2 films. The enhancement mechanism is investigated by a localized surface plasmon (LSP)-driven carrier diffusion model. These findings reveal an important strategy for high sensitivity and low energy cost PSDs while opening up new avenues for energy harvesting self-powered position sensors.

Graphene-enhanced lateral photovoltaic effect observed in the Ag nanoparticle-covered graphene/n-type silicon.

Graphene is a kind of two-dimensional material with a single-layer carbon structure and has been investigated in many high-performance photodetectors. The lateral photovoltaic effect (LPE) is widely used in the position-sensitive detectors (PSDs) owing to its linear response of photovoltage to the light position. In this Letter, a type of graphene-enhanced LPE is observed in the Ag nanoparticle-covered graphene/n-type Si. The LPE sensitivity can reach 97.3 mV/mm, much higher than the sensitivity of 1.3 mV/mm in the control sample of Ag/Si and 5.2 mV/mm of graphene/Si. Based on the photocarriers' diffusion mechanism, tailoring a photocarrier transfer at the interface of a heterojunction plays a key role for the enhancement. These findings exhibit great application potential of graphene in the field of PSDs and offer an effective method for the optimization of LPE devices.

Genetic variants associated with cytomegalovirus infection after allogeneic hematopoietic cell transplantation.

Human cytomegalovirus (CMV) reactivation is a frequent complication of allogeneic hematopoietic cell transplantation (HCT). Despite routine screening for CMV reactivation and early antiviral treatment, the rates of CMV-related complications after HCT remain high. Genetic variants in both the donor and recipient have been associated with the risk of CMV reactivation and disease after HCT, but these associations have not been validated, and their clinical importance remains unclear. In this study, we assessed 117 candidate variants previously associated with CMV-related phenotypes for association with CMV reactivation and disease in a cohort of 2169 CMV-seropositive HCT recipients. We also carried out a genome-wide association study (GWAS) for CMV reactivation and disease in the same cohort. Both analyses used a prespecified discovery and replication approach to control the risk of false-positive results. Among the 117 candidate variants, our analysis implicates only the donor ABCB1 rs1045642 genotype as a risk factor for CMV reactivation. This synonymous variant in P-glycoprotein may influence the risk of CMV reactivation by altering the efflux of cyclosporine and tacrolimus from donor lymphocytes. In the GWAS analysis, the donor CDC42EP3 rs11686168 genotype approached the significance threshold for association with CMV reactivation, although we could not identify a mechanism to explain this association. The results of this study suggest that most genomic variants previously associated with CMV phenotypes do not significantly alter the risk for CMV reactivation or disease after HCT.

Constructing time-invariant dynamic surveillance rules for optimal monitoring schedules.

Dynamic surveillance rules (DSRs) are sequential surveillance decision rules informing monitoring schedules in clinical practice, which can adapt over time according to a patient's evolving characteristics. In many clinical applications, it is desirable to identify and implement optimal time-invariant DSRs, where the parameters indexing the decision rules are shared across different decision points. We propose a new criterion for DSRs that accounts for benefit-cost tradeoff during the course of disease surveillance. We develop two methods to estimate the time-invariant DSRs optimizing the proposed criterion, and establish asymptotic properties for the estimated parameters of biomarkers indexing the DSRs. The first approach estimates the optimal decision rules for each individual at every stage via regression modeling, and then estimates the time-invariant DSRs via a classification procedure with the estimated time-varying decision rules as the response. The second approach proceeds by optimizing a relaxation of the empirical objective, where a surrogate function is utilized to facilitate computation. Extensive simulation studies are conducted to demonstrate the superior performances of the proposed methods. The methods are further applied to the Canary Prostate Active Surveillance Study (PASS).

Multiple Sulfur Isotopic Evidence for Sulfate Formation in Haze Pollution.

The mechanism of sulfate formation during winter haze events in North China remains largely elusive. In this study, the multiple sulfur isotopic composition of sulfate in different grain-size aerosol fractions collected seasonally from sampling sites in rural, suburban, urban, industrial, and coastal areas of North China are used to constrain the mechanism of SO2 oxidation at different levels of air pollution. The Δ33S values of sulfate in aerosols show an obvious seasonal variation, except for those samples collected in the rural area. The positive Δ33S signatures (0‰ < Δ33S < 0.439‰) observed on clean days are mainly influenced by tropospheric SO2 oxidation and stratospheric SO2 photolysis. The negative Δ33S signatures (-0.236‰ < Δ33S < ∼0‰) observed during winter haze events (PM2.5 > 200 µg/m3) are mainly attributed to SO2 oxidation by H2O2 and transition metal ion catalysis (TMI) in the troposphere. These results reveal that both the H2O2 and TMI pathways play critical roles in sulfate formation during haze events in North China. Additionally, these new data provide evidence that the tropospheric oxidation of SO2 can produce significant negative Δ33S values in sulfate aerosols.

A general framework for functionally informed set-based analysis: Application to a large-scale colorectal cancer study.

Genome-wide association studies (GWAS) have successfully identified tens of thousands of genetic variants associated with various phenotypes, but together they explain only a fraction of heritability, suggesting many variants have yet to be discovered. Recently it has been recognized that incorporating functional information of genetic variants can improve power for identifying novel loci. For example, S-PrediXcan and TWAS tested the association of predicted gene expression with phenotypes based on GWAS summary statistics by leveraging the information on genetic regulation of gene expression and found many novel loci. However, as genetic variants may have effects on more than one gene and through different mechanisms, these methods likely only capture part of the total effects of these variants. In this paper, we propose a summary statistics-based mixed effects score test (sMiST) that tests for the total effect of both the effect of the mediator by imputing genetically predicted gene expression, like S-PrediXcan and TWAS, and the direct effects of individual variants. It allows for multiple functional annotations and multiple genetically predicted mediators. It can also perform conditional association analysis while adjusting for other genetic variants (e.g., known loci for the phenotype). Extensive simulation and real data analyses demonstrate that sMiST yields p-values that agree well with those obtained from individual level data but with substantively improved computational speed. Importantly, a broad application of sMiST to GWAS is possible, as only summary statistics of genetic variant associations are required. We apply sMiST to a large-scale GWAS of colorectal cancer using summary statistics from ∼120, 000 study participants and gene expression data from the Genotype-Tissue Expression (GTEx) project. We identify several novel and secondary independent genetic loci.

High-Sensitivity Infrared Photoelectric Detection Based on WS2 /Si Structure Tuned by Ferroelectrics.

As one of the typical transition-metal dichalcogenides with distinct optical and electrical properties, WS2 exhibits tremendous potential for optoelectronic devices. However, its inherent band gap range limits the application in the infrared region. To overcome this draw-back and improve the sensitivity, P(VDF-CTFE) is used as a ferroelectric gate to control the states of WS2 /Si junctions and achieve an enhanced infrared photodetection. The polarization electric field not only broadens the range of absorption wavelength (405-1550 nm) but also greatly promotes the sensitivity of lateral photovoltaic effect (LPE) (from 198.6 to 503.2 mV mm-1 ). This phenomenon is attributed to the reduction of WS2 band gap and the change of potential barrier at the interface of the junction. Meanwhile, the response speed is improved significantly due to the increase of carrier initial kinetic energy. This new scheme for ferroelectric tuned LPE opens up a way to realize high-sensitivity, ultrafast, and stable infrared photodetection.

The role of WSC domain-containing protein encoding gene AOL_s00043g401 in the growth and nematode trapping of Arthrobotrys oligospora.

Arthrobotrys oligospora is a model nematode-trapping fungus that has been extensively investigated to understand the interactions between fungi and nematodes. Nematode capture by A. oligospora is a complex process in which recognition of nematodes is generally believed to be mediated by lectins from the fungi. Lectins are a group of carbohydrate-binding proteins that widely exist in microorganisms and contain specific glycosylation recognition domains. In this work, we report the effect of a putative WSC domain-containing protein encoding gene AOL_s00043g401 (g401) on the growth and nematode-trapping of A. oligospora. The g401 gene was knocked out using the homologous recombination approach, and the △g401 mutant strain was then evaluated for its growth rate, conidial yield and germination rate, adaptation to environmental stresses, and nematocidal activity. Interestingly, the deletion of the putative lectin gene g401 had no significant effect on saprophytic growth, conidial yield and germination rate, responses to high salt, surfactant, and strong oxidative environments, as well as nematode-trapping efficiency of A. oligospora. We speculate that this phenomenon might have been caused by an intrinsic genetic compensation of the g401 in this fungus. For instance, more copies of WSC domain encoding genes or PQQ-DH domain encoding genes were found in the genome of A. oligospora. These findings provide further experimental evidence on the effect of lectin-related functional proteins in A. oligospora on nematode capture and will help further analyze their potential roles in the biological control of nematodes in the future.

A putative F-box-domain-encoding gene AOL_s00076g207 regulates the development and pathogenicity of Arthrobotrys oligospora.

F-box protein is a key component of the Skp1-cullin-F-box-type ubiquitin ligase complex (SCF-ULC) that marks its target proteins with ubiquitin for proteasomal degradation. In this study, we explored the potential role of AOL_s00076g207 (Aog207) in Arthrobotrys oligospora, a model fungus for studying nematodes-fungi interactions. The Aog207 gene encodes a putative F-box protein of the SCF-ULC. Deletion of Aog207 could inhibit mycelial growth in TYGA and PDA media. More importantly, the conidial germination rate of ΔAog207 mutants was remarkably declined compared to that of wild-type (WT) strain, and the mutant strains were more sensitive toward chemical stressors than the WT strain. In addition, ΔAog207 mutants generated fewer traps and captured fewer nematodes than WT strain. In summary, Aog207 disruption significantly affected the pathogenicity, mycelial growth, conidial germination, environmental adaptation and trap formation of A. oligospora. These findings may facilitate a better understanding of the nematode predation mechanism of A. oligospora and provide an experimental basis for developing biological control agents against nematodes.

Recent Research Advances in Plasma Spraying of Bulk-Like Dense Metal Coatings with Metallurgically Bonded Lamellae.

Although thermal spray metallic coatings have been widely used for materials protection from wear, corrosion and oxidation, its porous feature limits the full utilization of materials potential. Moreover, the oxidation inherent to thermal spraying in the ambient atmosphere is detrimental to interlamellar bonding formation, which further degrades the performance of thermal spray metal coatings. How to tape out the full potential of spray materials in the form of the coating is a still great challenge to thermal spray coating technology. Facing such challenge, recent efforts have been made to deposit dense metallic coatings with sufficiently bonded lamellae by oxide-free molten droplets through atmospheric plasma spraying. In this paper, the strategies for depositing bulk-like metal coatings will be reviewed. The formation of the bulk-like coating through post-spray treatments is briefly reviewed including post-spray heat treatment and laser remelting following the brief introduction to the features of thermal spray metallic coatings. The effect of the substrate preheating temperature on the splat formation and subsequently the adhesion formation was examined to reveal the dominant limitation of resultant oxide scale. Then, the role of the deposition temperature on the formation of bulk-like metal deposits with neglecting the effect of oxidation during spraying by vacuum plasma spraying practices is shortly presented. The recent progress on the new strategies to develop spread-fusing bonding mechanism and in-situ in-flight deoxidizing mechanism through developing ultra-hot metallic droplets will be introduced. The thermodynamics and kinetics requirements for the in-situ in-flight deoxidizing through deoxidizer elements adding to alloy spray powders for achieving oxide-free molten droplets in the ambient atmosphere are examined. The conditions to develop the spread-fusing mechanism during the spreading of impacting molten metal droplet for metallurgical bonding are presented. It is obvious from this review paper that the realization of two mechanisms depends on both the spray materials design and heating control of in-flight particles. Through the generation of ultra-hot droplets by plasma spraying to achieve oxide-free molten droplets, strategically it will be possible to deposit bulk-like dense metallic coating through spread-fusing of splat surfaces with limited post-spray oxidation. Such strategies will tape out the full potential of coating materials and open up the new application fields for plasma spraying.

A Mixed-Effects Model for Powerful Association Tests in Integrative Functional Genomics.

Genome-wide association studies (GWASs) have successfully identified thousands of genetic variants for many complex diseases; however, these variants explain only a small fraction of the heritability. Recently, genetic association studies that leverage external transcriptome data have received much attention and shown promise for discovering novel variants. One such approach, PrediXcan, is to use predicted gene expression through genetic regulation. However, there are limitations in this approach. The predicted gene expression may be biased, resulting from regularized regression applied to moderately sample-sized reference studies. Further, some variants can individually influence disease risk through alternative functional mechanisms besides expression. Thus, testing only the association of predicted gene expression as proposed in PrediXcan will potentially lose power. To tackle these challenges, we consider a unified mixed effects model that formulates the association of intermediate phenotypes such as imputed gene expression through fixed effects, while allowing residual effects of individual variants to be random. We consider a set-based score testing framework, MiST (mixed effects score test), and propose two data-driven combination approaches to jointly test for the fixed and random effects. We establish the asymptotic distributions, which enable rapid calculation of p values for genome-wide analyses, and provide p values for fixed and random effects separately to enhance interpretability over GWASs. Extensive simulations demonstrate that our approaches are more powerful than existing ones. We apply our approach to a large-scale GWAS of colorectal cancer and identify two genes, POU5F1B and ATF1, which would have otherwise been missed by PrediXcan, after adjusting for all known loci.

Heterojunction interface-induced enhancement of position-sensitive photodetection in the nano-film of Ti/SrTiO3 based on the p-type silicon.

Complex oxide perovskites exhibit a range of novel, to the best of our knowledge, physical phenomena and have gained popularity as a material system in the past decades. Strontium titanate (SrTiO3) is an iconic material among oxide perovskite due to its unusual electronic transport behavior and has been investigated in many electronic devices. In this Letter, a type of SrTiO3 nano-film-induced enhancement of lateral photovoltaic effect (LPE) is observed in the heterojunction of Ti/SrTiO3/p-type Si. Optimizing the thickness of SrTiO3, the LPE sensitivity can reach 123.2 mV/mm, which is much higher than the sensitivity in the control samples of Ti/Si (55.3 mV/mm) and SrTiO3/Si (∼0mV/mm). These findings offer an effective way to improve the sensitivity and will be helpful in the development of oxide-based photodetection devices.

High performance and low power consumption resistive random access memory with Ag/Fe2O3/Pt structure.

Due to magnetic field tunability and the abundance of iron in the Earth's crust, iron oxide-based resistive random access memory (RRAM) is considered to be low cost and potential for multi-level storage. However, the relatively high operation voltage (>1 V) and small storage window (<100) limit its application. In this work, the devices with simple Ag/Fe2O3/Pt structure exhibit typical bipolar resistive switching with ultralow set voltage (Vset) of 0.16 V, ultralow reset voltage (Vreset) of -0.04 V, high OFF/ON resistance ratio of 103, excellent cycling endurance more than 104and good retention time longer than 104s. Each major parameter has about an order of magnitude improvement compared to the previous data. The devices demonstrate outstanding stable low power consumption quality. Based on the analysis of the experimental results, a percolation model of silver ion migration was established and confirmed that low operation voltage is attributed to the amorphous oxide layer with large porosity. During electrical testing, the compliance current (Ic) and maximum reset voltage (Vmax) can also affect the device performance. This discovery suggests Fe2O3memristor has significant potential for application and provides a new idea for the realization of high-performance low-power RRAM.

Improved uniformity in resistive switching behaviors by embedding Cu nanodots.

An improvement in the uniformity of resistive switching behaviors by embedding Cu nanodots is observed in Ta2O5 memory cells. In the conventional device structure, the growth of conductive filaments tends to be random and uncontrollable, which is the major obstacle for memory cell fabrication. By using a bottom electrode covered in metal nanodots, the field distribution in the electrolyte layer is modified and the conductive filaments prefer to grow along the direction of the Cu nanodots. Such controlled growth of conductive filaments leads to a reduced variation of switching parameters, as well as the disappearance of an unpredictable multistep resistive switching phenomenon, which is helpful for improving the device stability. Meanwhile, scaling relations are used to reveal the relationship between switching parameters and the microstructure of conductive filaments. By overlapping the scaling relations and electric field simulation, a model is proposed to explain the improvement in resistive switching performance caused by the presence of embedded Cu nanodots.

Self-Contained High-SNR Underwater Acoustic Signal Acquisition Node and Synchronization Sampling Method for Multiple Distributed Nodes.

Aiming at the application demand in underwater noise monitoring, observation of marine animal, antisubmarine and underwater target localization, a high-SNR underwater acoustic signal acquisition (UASA) node that combines a self-contained acquisition system and floating platform is designed to improve the acquisition performance of a single UASA node, and a high-accuracy synchronization sampling method among multiple distributed UASA nodes based on master-slave dual phase-locked loops (MSDPLL) is proposed to improve the synchronization sampling accuracy. According to the equivalent model of hydrophone and application requirements, low noise signal conditioning circuit and large-capacity data storage modules are designed. Based on the long-term monitoring requirements for underwater acoustic signal and distributed positioning requirements for underwater targets, the structure of a single UASA node is designed and MSDPLL is developed for high-accuracy synchronization sampling among multiple UASA nodes. Related experimental results verified the performance of the UASA node and the synchronization sampling method.

A Generalized Integration Approach to Association Analysis with Multi-category Outcome: An Application to a Tumor Sequencing Study of Colorectal Cancer and Smoking.

Cancer is a heterogeneous disease, and rapid progress in sequencing and -omics technologies has enabled researchers to characterize tumors comprehensively. This has stimulated an intensive interest in studying how risk factors are associated with various tumor heterogeneous features. The Cancer Prevention Study-II (CPS-II) cohort is one of the largest prospective studies, particularly valuable for elucidating associations between cancer and risk factors. In this paper, we investigate the association of smoking with novel colorectal tumor markers obtained from targeted sequencing. However, due to cost and logistic difficulties, only a limited number of tumors can be assayed, which limits our capability for studying these associations. Meanwhile, there are extensive studies for assessing the association of smoking with overall cancer risk and established colorectal tumor markers. Importantly, such summary information is readily available from the literature. By linking this summary information to parameters of interest with proper constraints, we develop a generalized integration approach for polytomous logistic regression model with outcome characterized by tumor features. The proposed approach gains the efficiency through maximizing the joint likelihood of individual-level tumor data and external summary information under the constraints that narrow the parameter searching space. We apply the proposed method to the CPS-II data and identify the association of smoking with colorectal cancer risk differing by the mutational status of APC and RNF43 genes, neither of which is identified by the conventional analysis of CPS-II individual data only. These results help better understand the role of smoking in the etiology of colorectal cancer.

Tracing the transboundary transport of atmospheric Particulate Bound Mercury driven by the East Asian monsoon.

Taking Beijing-Tianjin-Hebei (BTH) with severe atmospheric mercury (Hg) and PM2.5 pollution as a typical region, this study clarified the characteristics and transboundary transport of atmospheric Particulate Bound Mercury (PBM2.5) affected by the East Asian monsoon. Five sampling sites were conducted in rural, suburban, urban, industrial, and coastal areas of BTH from northwest to southeast along the East Asian monsoon direction. PBM2.5 showed increasing concentrations from northwest to southeast and negative δ202Hg values, indicating significant contributions from anthropogenic sources. However, the mean Δ199Hg values of PBM2.5 at the five sites were significantly positive, probably triggered by the photoreduction of Hg(II) during long-range transport driven by the East Asian monsoon. Apart from local anthropogenic emissions as the primary sources, the transboundary transport of PBM2.5, driven by west and northwest air masses originating in Central Asia and Russia, contributed significantly to the PBM2.5 pollution of BTH. Moreover, these air masses reaching BTH would carry elevated PBM2.5 concentrations further transported to the ocean by the East Asian monsoon. In contrast, the southeast air masses transported from the ocean by the East Asian monsoon in summer diluted inland PBM2.5 pollution. This study provides insight into the atmospheric Hg circulation affected by the East Asian monsoon.

Slight transition in Chinese atmospheric Pb isotopic fingerprinting due to increasing foreign Pb.

Atmospheric lead (Pb) pollution negatively affects human health and ecosystem, and extensive research is required to identify its sources and develop robust mitigation methods. In this study, the concentration and isotopic composition of Pb in fine particulate matter (PM2.5) at five sites in the China's Beijing-Tianjin-Hebei (BTH) region were analyzed. The results showed that the Pb concentration in the BTH region declined along the northwest direction in winter owing to the East Asian monsoon. Pb isotopic signatures confirmed that anthropogenic activities significantly contributed to Pb pollution, compared with natural sources. With the increasing import of foreign Pb (with a relatively lower 208Pb/206Pb ratio) to China, we hypothesized that the unique isotopic signature of Pb in Chinese aerosols may decline over time. Therefore, the application of the isotopic approach for quantifying Pb transported from China should be carefully appraised in future research to provide a realistic estimate of the contribution of local sources and the transboundary effect consistent with air mass trajectories analysis. This study provides a theoretical reference for supporting the utilization of Δ208Pb values for better clarify the transboundary impact of Pb pollution and to reduce international disputes.

Growth and metastases of human lung cancer are inhibited in mouse xenografts by a transition state analogue of 5'-methylthioadenosine phosphorylase.

The S-adenosylmethionine (AdoMet) salvage enzyme 5'-methylthioadenosine phosphorylase (MTAP) has been implicated as both a cancer target and a tumor suppressor. We tested these hypotheses in mouse xenografts of human lung cancers. AdoMet recycling from 5'-methylthioadenosine (MTA) was blocked by inhibition of MTAP with methylthio-DADMe-Immucillin-A (MTDIA), an orally available, nontoxic, picomolar transition state analogue. Blood, urine, and tumor levels of MTA increased in response to MTDIA treatment. MTDIA treatment inhibited A549 (human non-small cell lung carcinoma) and H358 (human bronchioloalveolar non-small cell lung carcinoma cells) xenograft tumor growth in immunodeficient Rag2(-/-)γC(-/-) and NCr-nu mice. Systemic MTA accumulation is implicated as the tumor-suppressive metabolite because MTDIA is effective for in vivo treatment of A549 MTAP(-/-) and H358 MTAP(+/+) tumors. Tumors from treated mice showed increased MTA and decreased polyamines but little alteration in AdoMet, methionine, or adenine levels. Gene expression profiles of A549 tumors from treated and untreated mice revealed only modest alterations with 62 up-regulated and 63 down-regulated mRNAs (≥ 3-fold). MTDIA antitumor activity in xenografts supports MTAP as a target for lung cancer therapy.

The isotopic patterns and source apportionment of nitrate and ammonium in atmospheric aerosol.

Nitrate (NO3-) and ammonium (NH4+) are the major components in inorganic aerosol. However, their sources and formation processes remain unclear. This study conducted a year-round field measurement of TSP, PM2.5 and PM1.0 in five different sites in the Beijing-Tianjin-Hebei (BTH) region to determine the concentrations of water-soluble inorganic ions (WSIIs) and the isotopic compositions of inorganic nitrogen (δ15N-NH4+, δ15N-NO3-, and δ18O-NO3-). The results showed the highest concentration of WSIIs in winter and lowest in summer. δ15N-NO3-, δ18O-NO3-, and δ15N-NH4+ were in the range of -6.1-18.2, 52.2-103.8, and -28.7-36.2‰, respectively. The seasonal variations of δ15N-NO3- and δ15N-NH4+ were an indication of relative contributions of the main sources and effects of meteorological conditions. The source apportionment identified fossil fuel combustion (38.2-50.6%), agricultural emissions (18-24.7%), biomass burning (16.3-22.7%), and road dust/soil (8.7-23.4%) were the main sources of inorganic aerosols. The local sources and regional migration contributed to the level of inorganic aerosol pollution. In winter, the aerosol in the BTH region was affected by the air mass from the northwest. While in spring and summer, the air mass was mainly from the South China. The low temperature and high relative humidity favored to the formation of inorganic nitrogen aerosol, and solar radiation affected the formation processes of inorganic aerosols by changing the oxidation pathway of NO3- and accelerating the volatilization and dissociation of ammonium nitrate (NH4NO3). This study discovered the main source contributions of inorganic nitrogen aerosol using N and O isotopes composition, and the obtained information has a great importance in understanding the effects of meteorological conditions on formation and the contribution of regional transport.