Double Droplets Impact an Inclined Superhydrophobic Surface.

The rebound dynamics of double droplets impacting an inclined superhydrophobic surface decorated with macro-ridges are investigated via lattice Boltzmann method (LBM) simulations. Four rebound regions are identified, that is, the no-coalescence-rebound (NCR), the partial-coalescence-rebound of the middle part bounces first (PCR-M), and the side part bounces first (PCR-S), as well as the complete-coalescence-rebound (CCR). The occurrence of the rebound regions strongly depends on the droplet arrangement, the center-to-center distance of the droplets, and the Weber number. Furthermore, the contact time is closely related to the rebound regions. The PCR-M region can significantly reduce the contact time because the energy dissipation in this region may decrease which can promote the rebound dynamic. Intriguingly, the contact time is also affected by the droplet arrangement; i.e., droplets arranged parallel to the ridge dramatically shorten the contact time since this arrangement increases the asymmetry of the liquid film. Therefore, for multidrop impact, the contact time can be effectively manipulated by changing the rebound region and the droplet arrangement. This work focuses on elucidating the wetting behaviors, rebound regions, and contact time of the multiple-droplet impacting an inclined superhydrophobic surface decorated with macro-ridges.

Identification and validation of a novel nine-gene prognostic signature of stem cell characteristic in hepatocellular carcinoma.

Currently, cancer stem cells (CSCs) are regarded as the most promising target for cancer therapy due to their close association with tumor resistance, invasion, and recurrence. Thus, identifying CSCs-related genes and constructing a prognostic risk model associated with CSCs may be crucial for hepatocellular carcinoma (HCC) therapy. Xena Browser was used to download gene expression profiles and clinical data, while MSigDB was used to obtain genes associated with CSCs. Firstly, the non-negative matrix factorization (NMF) algorithm was used to cluster the HCC samples based on CSCs-related genes. To evaluate the predictive performance of the risk model, the receiver operating characteristic curves (ROC) and Kaplan-Meier analysis were used. The R package "rms" was used to construct the final nomogram based on risk scores and clinical characteristics. Based on 449 CSCs-related genes, a total of 588 HCC samples from TCGA-LIHC and ICGC-LIRI_JP were classified into four molecular subtypes with marked differences in survival and mRNA stemness index (mRNAsi) between subtypes. Univariate Cox regression, multivariate Cox regression, and LASSO regression analyses were performed on a total of 1417 differentially expressed genes (DEGs) between subtypes, and a nine-gene prognostic model was constructed with TTK, ST6GALNAC4, SPP1, SGCB, MEP1A, HTRA1, CD79A, C6, and ATP2A3. In both the training and testing sets and the external validation cohort, the risk model performed well in predicting HCC patients' survival. A nomogram was constructed and had high predictive efficacy in short-term survival. In comparison with the other two prognostic models, our nine-gene signature model performed best. We constructed a nine-gene signature model to predict the survival of HCC patients, which has good predictive efficacy and stability. The model may contribute to guiding the prognostic assessment of HCC patients in clinical practice.

Longitudinal analysis of the mediating role of self-perception of aging in the relationship between frailty and intrinsic capacity: A cross-lagged mediation model.

OBJECTIVES: The causal relationship between intrinsic capacity and frailty in older adults, as well as the underlying temporal mechanisms, remained poorly understood. The study aimed to investigate the causal association between intrinsic capacity and frailty while exploring the potential mediating role of self-perception of aging. MEASUREMENTS: A survey was conducted with a sample of 429 participants who completed measures of intrinsic capacity, self-perception of aging, and frailty at baseline and were followed for one year. The relationships between these variables were assessed using an autoregressive cross-lagged model. RESULTS: The study found reciprocal associations between intrinsic capacity and frailty (p < 0.01). Furthermore, the results indicated that self-perception of aging partially mediated the effect of frailty at baseline (T1) on intrinsic capacity at one-year follow-up (T2) (ß = -0.02, confidence interval: [-0.055, -0.004]). However, the reverse causation was not observed. CONCLUSIONS AND IMPLICATIONS: This study demonstrates a bidirectional causal relationship between intrinsic capacity and frailty in older adults. Self-perception of aging plays a significant mediating role in this relationship. Older adults with a worse level of frailty should be made aware of the potentially vicious cycle related to self-perception of aging, which can negatively affect their intrinsic capacity. Maintaining a positive self-perception of aging may help preserve physical and psychological reserves, maintain intrinsic capacity, and slow the decline of frailty.

X-ray-triggered through-space charge transfer and photochromism in silver nanoclusters.

Materials exhibiting X-ray-induced photochromism have consistently piqued the interest of researchers. Exploring the photochromic properties of such materials is valuable for understanding the structural changes and electron transfer processes that occur under high energy radiation, such as X-ray irradiation. Here, a crystalline silver(I) nanocluster synthesized from tert-butylacetylene silver was found to have the ability to exhibit color and photoluminescence changes upon exposure to X-ray radiation. The responsive behavior was observed across a wide temperature range of 100-300 K, with the ability to respond particularly well to soft X-rays (λ > 1 Å) and exhibit light responsiveness to hard X-rays (λ < 1 Å). By combining experimental findings including X-ray diffraction, X-ray photoelectron spectroscopy, electron spin resonance, etc. with theoretical calculations, we have proposed that X-ray irradiation induces electron transfer from chloride (Cl-) located in the center of the silver(I) nanocluster to the surrounding Ag14 in the skeleton. This represents the first documented example in which electron transfer induced by X-ray excitation has been observed, accompanied by a photochromism process, in silver nanoclusters. This study contributes to our understanding of X-ray-induced photochromism and the electron transfer process in silver cluster compounds. It also provides valuable insights and potential design strategies for applications such as photochromism, photoluminescence color change, and photoenergy conversion.

Discovery of potent STAT3 inhibitors using structure-based virtual screening, molecular dynamic simulation, and biological evaluation.

Introduction: Signal transducer and activator of transcription 3 (STAT3) is ubiquitously hyper-activated in numerous cancers, rendering it an appealing target for therapeutic intervention. Methods and results: In this study, using structure-based virtual screening complemented by molecular dynamics simulations, we identified ten potential STAT3 inhibitors. The simulations pinpointed compounds 8, 9, and 10 as forming distinct hydrogen bonds with the SH2 domain of STAT3. In vitro cytotoxicity assays highlighted compound 4 as a potent inhibitor of gastric cancer cell proliferation across MGC803, KATO III, and NCI-N87 cell lines. Further cellular assays substantiated the ability of compound 4 to attenuate IL-6-mediated STAT3 phosphorylation at Tyr475. Additionally, oxygen consumption rate assays corroborated compound 4's deleterious effects on mitochondrial function. Discussion: Collectively, our findings position compound 4 as a promising lead candidate warranting further exploration in the development of anti-gastric cancer therapeutics.

Design and development of a rapid meat detection system based on RPA-CRISPR/Cas12a-LFD.

In recent years, meat adulteration safety incidents have occurred frequently, triggering widespread attention and discussion. Although there are a variety of meat quality identification methods, conventional assays require high standards for personnel and experimental conditions and are not suitable for on-site testing. Therefore, there is an urgent need for a rapid, sensitive, high specificity and high sensitivity on-site meat detection method. This study is the first to apply RPA combined with CRISPR/Cas12a technology to the field of multiple meat identification. The system developed by parameter optimization can achieve specific detection of chicken, duck, beef, pork and lamb with a minimum target sequence copy number as low as 1 × 100 copies/µL for 60 min at a constant temperature. LFD test results can be directly observed with the naked eye, with the characteristics of fast, portable and simple operation, which is extremely in line with current needs. In conclusion, the meat identification RPA-CRISPR/Cas12a-LFD system established in this study has shown promising applications in the field of meat detection, with a profound impact on meat quality, and provides a model for other food safety control programs.

Erratum: Myeloid cell-derived LL-37 promotes lung cancer growth by activating Wnt/ß-catenin signaling: Erratum.

[This corrects the article DOI: 10.7150/thno.30726.].

Association between positive control in self-perceptions of aging and motoric cognitive risk syndrome among Chinese community-dwelling older adults: a cross-sectional study.

BACKGROUND: Self-perceptions of aging (SPA) are important psychosocial factors that lead to a wide range of outcomes including dementia. However, the relationships between positive SPA and motoric cognitive risk syndrome (MCR) which is a predementia syndrome are still unknown. This study aimed to reveal the associations of positive control and aging awareness of SPA with the risk of MCR and its components. METHODS: A cross-sectional design was conducted among 1137 Chinese community-dwelling older adults. Positive control and aging awareness were defined by two dimensions of SPA (Positive control and Timeline chronic). MCR was determined according to definition. Multivariable logistic regression was used to examine the associations. RESULTS: The overall prevalence of MCR was 11.5% (mean age = 71.62 ± 5.22). After adjusting for depression, anxiety, and cognitive function, positive control was associated with reduced risk of MCR (OR = 0.624, 95% CI 0.402-0.969, P = 0.036), subjective cognitive complaints (SCC) (OR = 0.687, 95% CI 0.492-0.959, P = 0.027), and gait speed (GS) (OR = 0.377, 95% CI 0.197-0.720, P = 0.003), respectively. Aging awareness was merely related to increased risk of MCR (OR = 1.386, 95% CI 1.062-1.810, P = 0.016). CONCLUSIONS: This study highlights the crucial associations of positive control and aging awareness with MCR and its components. Our results emphasize that positive belief in control and adaptive aging awareness might be promising targets for preventing MCR.

Health information sharing on social media: quality assessment of short videos about chronic kidney disease.

INTRODUCTION: Chronic kidney disease (CKD), which affects about 10% of global population, has become a global public health crisis in recent decades. It is well recognized that health information dissemination could change health behaviors, thereby greatly improving the early diagnosis and prevention of diseases. Due to fast dissemination, wide audience, intuitive and vivid, popularization through short videos has rapidly developed into the new main battlefield of health information. The objective of this study was to describe the properties of the CKD-related health information on short video apps. METHODS: Searching on short video apps with high-frequency words in kidney disease as keywords, the basic information of the uploaders was retrieved and extracted short video. Five quality dimensions, awareness, popularity, utility, validity and quality, of each video were assessed with numeric rating scale (NRS) by five volunteers with CKD and three nephrologists. RESULTS: From the platform of douyin, 65 uploaders and their 3973 short videos of CKD-related health information were investigated in this study. Most information of short videos had relatively high level in awareness, popularity and utility assessment, but some information had relatively low level in validity and quality assessment; 24 (36.9%) uploaders were from governmental hospital (tertiary hospital); 19 uploaders (29.2%) uploaded more than 100 short videos and 49 uploaders (75.4%) updated their videos weekly, and 16 uploaders (24.6%) didn't update short videos more than one month. There were 4 uploaders (6.2%) have more than 1 million follows, and 39 uploaders (60%) had follows less than 10,000. "Lifestyles", "Common symptoms of kidney disease" and "Nephritis or kidney disease" were the three main contents of these short videos. The comprehensive data of uploaders with millions of follows in nephrology specialty were much lower than that of orthopedics and other specialty. CONCLUSION: The validity and quality of short video is still unsatisfactory, and CKD-related health information also need to be led and improved, although the awareness, popularity, and utility of health information about CKD is acceptable. The public should be selective and cautious in seeking CKD information on social media.

Post-synthesis functionalization of ZIF-90 with sulfonate groups for high proton conduction.

Introducing sulfonic acid groups into MOF materials is one of the effective approaches to enhance proton conduction. Here, we attempted to prepare a new post-modified ZIF-90-based material by addition reaction of the aldehyde group with bisulfite to obtain partially functionalized ZIF-90-SO3Na(2.3). ZIF-90-SO3Na(2.3) exhibits a high proton conductivity of 2.26 × 10-2 S cm-1 at 98% RH and 100 °C.

Depression and Cognition Mediate the Effect of Self-Perceptions of Aging Over Frailty Among Older Adults Living in the Community in China.

Objectives: The aims of the study were first to investigate the association between self-perceptions of aging and frailty and second to determine whether self-perceptions of aging affects frailty via depressive symptoms and cognitive status among older adults living in the community in China. Methods: Among 850 older adults who participated in this cross-sectional study, 822 older adults made valid responses to Tilburg Frailty Indicator, Brief Aging Perceptions Questionnaire, UCLA loneliness scale-8, Mini-Mental State Examination, and Patient Health Questionnaire-9 between March to December 2019. The possible pathways of self-perceptions of aging affecting frailty were analyzed based on the structural equation modeling analysis. Results: A total of 21.53% of older adults reported frailty. Correlation analyses showed that higher degrees of frailty were related to greater loneliness, more depressive symptoms, more negative self-perceptions of aging, worse locomotive function, and cognitive status (r = 0.267, r = 0.440, r = 0.481, r = 0.451, r = -0.337; p < 0.001). Multiple regression analysis showed that loneliness, depressive symptoms, self-perceptions of aging, locomotive function, and cognitive status were the five factors to be entered the regression equation, and the variance of joint explanation was 46.60%. SPA had a direct effect on frailty (ß = 0.306 and p < 0.001), and SPA indirectly affects frailty by independently affecting depressive symptoms (ß = 0.391, 95% CI [0.027, 0.061], and p < 0.001) or cognitive status (ß = 0.148, 95% CI [0.009, 0.024], and p < 0.001) of older adults. Conclusion: These findings help explain the potential psychological mechanisms through which SPA impacts frailty and may aid community healthcare providers in China in identifying individuals at high risk of frailty. The results suggest that health staff should help older adults improve their perspectives on aging, alleviate or prevent depressive symptoms, and improve cognitive status to delay the progress of frailty and promote healthy aging.

Three rare-earth incorporating 6-peroxotantalo-4-selenates and catalytic activities for imidation reaction.

Functionalization with belt lanthanide groups allows for the crystallization and structural characterization of homometallic selenotantalates, CsK[Ln(H2O)6Se4(TaO2)6(OH)3O18]·nH2O (Ln = Eu/Gd, n = 14 (STD-Eu, STD-Gd) and Ln = Lu, n = 12 (STD-Lu)). The basket-shaped {Se4(TaO2)6} archetype is assembled in a simple one-pot reaction of Na2SeO3 and K8[Ta6O19]·17H2O in acidic aqueous medium (pH 2) and in the presence of hydrogen peroxide. This unit has been proven to be an effective precursor for the preparation of a range of new POMs containing the {Se4(TaO2)6} unit. The lanthanide derivatives STD-Eu, STD-Gd and STD-Lu have been fully characterized with single-crystal X-ray diffraction, IR spectroscopy, TG analysis and PXRD in the solid state. The photoluminescence and lifetime decay behaviours of STD-Eu have been studied at room temperature, and the photoluminescence spectrum displays the characteristic emission of the Eu3+ cation. In addition, the catalytic activities of STD-Eu, STD-Gd and STD-Lu on the reaction of phthalic anhydride with phenylamines have been investigated. STD-Eu shows good catalytic activities for imidation reactions.

Chiral {Ni6PW9} Cluster-Organic Framework: Synthesis, Structure, and Properties.

A chiral three-dimensional polyoxometalate cluster-organic framework (POMCOF) H3[(btc)Ni6(µ3-OH)3(H2O)5(B-α-PW9O34)]·17H2O (1, btc = 1,2,4-benzenetricarboxylate) has been made under hydrothermal conditions in the absence of amine or chiral starting reagents. 1 shows high stability in CH3CN/DMF (1:3), acidic, and basic solutions with the pH ranging from 2 to 12 for 5 days. The UV-vis reflectance spectra and Mott-Schottky measurements reveal that 1 could be a suitable catalyst for photocatalysis. Visible-light-driven H2 evolution studies have demonstrated that 1 is an ecofriendly, efficient, and recyclable catalyst with a H2 evolution rate of 1058.24 µmol h-1g-1. Nonlinear optical (NLO) measurement reveals that 1 exhibits a second-harmonic generation (SHG) response of about 1.4 times that of KH2PO4 (KDP), indicating that 1 is a potential NLO material as well.

Urinary Exosomal Long Noncoding RNA TERC as a Noninvasive Diagnostic and Prognostic Biomarker for Bladder Urothelial Carcinoma.

PURPOSE: Bladder cancer is one of the most common urological malignancies worldwide, and approximately 90% of bladder cancer cases are histologically typed as bladder urothelial carcinoma (BLCA). Exosomes are 30 to 200 nm extracellular vesicles that transport microRNAs, long noncoding RNAs (lncRNAs), mRNAs, circular RNAs, and proteins across tissues and through circulation. Urinary exosomes may contain genetic information from tumor cells. Herein, we explored the clinical significance of urinary exosomal lncRNA telomerase RNA component (TERC) levels to provide an urgently needed diagnostic and prognostic biomarker for BLCA. MATERIALS AND METHODS: In this study, we used RNA-sequencing of samples from four BLCA patients and three healthy controls to identify that TERC was differentially expressed in urinary exosomes. We then used quantitative PCR in different types of clinical samples to validate the biomarker and analyzed results using receiver operating characteristic curves. RESULTS: We found that TERC was significantly upregulated in urinary exosomes from BLCA patients compared with those from healthy controls (P < 0.0001). Urinary exosomal TERC showed higher sensitivity (78.65%) and accuracy (77.78%) than existing indicators including nuclear matrix protein-22 and urine cytometry. Using the cut-off value 4.302, the area under the curve for urinary exosomal TERC was 0.836 (95% confidence interval: 0.768-0.891, P < 0.0001). Furthermore, this noninvasive assay could distinguish low-grade and high-grade tumors (P = 0.0153). CONCLUSIONS: TERC is enriched in urinary exosomes from BLCA patients. Urinary exosomal TERC could become a diagnostic and prognostic biomarker for BLCA that allows clinicians to realize noninvasive detection of BLCA.

N6-Methyladenosine-Regulated mRNAs: Potential Prognostic Biomarkers for Patients With Lung Adenocarcinoma.

Aberrant regulation of m6A mRNA modification can lead to changes in gene expression, thus contributing to tumorigenesis in several types of solid tumors. In this study, by integrating analyses of m6A methylation and mRNA expression, we identified 84 m6A-regulated mRNAs in lung adenocarcinoma (LUAD). Although the m6A methylation levels of total RNA in LUAD patient tumor tissue were reduced, the majority (75.2%) of m6A-regulated mRNAs were hypermethylated. The m6A-hypermethylated mRNAs were mainly enriched in terms related to transcription factor activity. We established a 10-m6A-regulated-mRNA signature score system through least absolute shrinkage and selection operator Cox regression analysis, with its predictive value validated by Kaplan-Meier curve and time-dependent receiver operating characteristic curves. RFXAP and KHDRBS2 from the signature also exhibited an independent prognostic value. The co-expression and interaction network analyses demonstrated the strong correlation between m6A regulators and the genes in the signature, further supporting the results of the m6A methylation modification patterns. These findings highlight the potential utility of integrating multi-omics data (m6A methylation level and mRNA expression) to accurately obtain potential prognostic biomarkers, which may provide important insights into developing novel and effective therapies for LUAD.

TRIM16 overexpression inhibits the metastasis of colorectal cancer through mediating Snail degradation.

Tripartite motif containing 16 (TRIM16) is a member of the tripartite motif protein family and functions as a potential tumor suppressor in several cancers. However, the specific function and clinical significance of TRIM16 in colorectal cancer (CRC) remains unclear. In this study, we observed that low TRIM16 expression was detected frequently in primary colorectal cancer (CRC) tissues and was closely associated with a better prognosis. Functional studies demonstrate that TRIM16 overexpression notably inhibits the metastasis abilities of CRC in vivo and in vitro. Mechanistically, our results demonstrated that TRIM16 directly bound and ubiquitinated Snail family transcriptional repressor 1 (Snail), an important transcriptional factor of the epithelial-mesenchymal transition (EMT) process suppressing the EMT in CRC. Additionally, our data revealed that the inhibition effect of TRIM16 on cancer metastasis was dependent on Snail degradation. Collectively, our study is the first to report that TRIM16 plays a crucial anti-tumor role in CRC tumorigenesis. We also provided novel evidence that TRIM16 might act as a prognostic and therapeutic target to assess and inhibit CRC progression.

{Cu8} Cluster-Sandwiched Polyoxotungstates and Their Polymers: Syntheses, Structures, and Properties.

Four inorganic-organic hybrid octa-Cu cluster sandwiched polyoxotungstates (POTs), [Cu8(H2O)2(en)4(B-α-H2SiW9O34)2] (1), [Cu8(H2O)2(en)4(B-α-H2GeW9O34)2] (2), K2[Cu8(en)4(B-α-HSiW9O34)2]·6H2O (3), and K2[Cu8(en)4(B-α-HGeW9O34)2]·2H2O (4) (en = ethylenediamine), were hydrothermally made and characterized by single-crystal X-ray diffraction, infrared spectra, powder X-ray diffraction, and thermogravimetric analysis, respectively. Structure analysis reveals that the polyoxoanion of 1/2 is a discrete dimer built by two trivalent Keggin [B-α-XW9O34]10- (X = Si/Ge) fragments and one octa-Cu cluster, whereas 3 and 4 display a two-dimensional network built by octa-Cu-sandwiched POT units via substitution of coordinated water on polyanions of 1 and 2 and further expand into a three-dimensional framework via K cation bridges. Ultraviolet-visible diffuse reflectance spectra reveal that 1-4 are potential semiconductor materials. Moreover, its visible light-driven catalytic H2 evolution activity, electrochemical properties, catalysis for oxygenation reactions of thioethers, and magnetic behaviors have been investigated in detail.

Acupuncture combined with moxibustion for insomnia after stroke: A protocol for systematic review and meta analysis.

BACKGROUND: Stroke is the main cause of death and disability in the world and insomnia is a common complication of stroke patients. Insomnia will not only seriously affect the prognosis and quality of life of patients with stroke, but even cause the recurrence of stroke. Many studies have proved that acupuncture and moxibustion can effectively improve insomnia symptoms. This study will systematically evaluate the effectiveness and safety of acupuncture combined with moxibustion in treating insomnia after stroke. METHODS: The following 8 databases will be searched from the inception to October 31, 2020, including China National Knowledge Infrastructure Database (CNKI), Chinese Scientific Journal Database (VIP database), China Biomedical Literature Database (CBM), Wanfang Data Chinese Database, PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), Allied and Alternative Medicine Database (AMED), Excerpt Medica Database (Embase). We will also search for ongoing trials from the World Health Organization International Clinical Trial Registration Platform search portal, Chinese Clinical Trial Register, Clinical trials.gov. In addition, the reference lists of studies meeting the inclusion criteria will also be searched for achieving the comprehensive retrieval to the maximum. All randomized controlled trials of acupuncture and moxibustion in treating insomnia after stroke will be included. Two reviewers will conduct literature screening, data extraction, and quality evaluation respectively. The main outcome is the Pittsburgh sleep quality index (PSQI), and the secondary outcomes include clinical efficacy, quality of life, and safety. RevMan V.5.4.1 will be used for meta-analysis. We will express the results as risk ratio (RR) with 95% confidence intervals (CIs) for dichotomous data and mean difference (MD) or standard mean difference (SMD) 95% CIs for continuous data. RESULTS: This study will provide a comprehensive review of the available evidence of acupuncture combined with moxibustion in treating insomnia after stroke. CONCLUSION: The conclusion of our study will provide the updated evidence to judge the effectiveness and safety of acupuncture combined with moxibustion for the treatment of insomnia after stroke. TRIAL REGISTRATION NUMBER: PROSPERO CRD42020216720.

Evaluation of atmospheric sources of PCDD/Fs, PCBs and PBDEs around an MSWI plant using active and passive air samplers.

This study evaluated the spatial distributions and concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in ambient air around a municipal solid waste incineration (MSWI) plant located in eastern China in two sampling campaigns within one year. Twenty high-volume samples and 27 passive air samples were collected from May 2012 to May 2013. The mean sampling rate of the passive sampler was estimated to be 3.8 ± 1.8 m3 d-1 in summer and autumn, while the mean sampling rate was 2.8 ± 1.0 m3 d-1 in winter and spring. Hence, the annual mean sampling rate was approximately 3.2 ± 1.4 m3 d-1. The mean levels of PCDD/Fs, PCBs, PBDEs (excluding BDE-209) and BDE-209 in the passive air samples varied in the ranges of 0.086 ± 0.058-0.76 ± 0.51 pg TEQ m-3, 39 ± 26-170 ± 120 pg m-3, 3.3 ± 2.2-36 ± 24 pg m-3 and 58 ± 39-300 ± 150 pg m-3, respectively. The levels, congener profiles and spatial distributions of PCDD/Fs, PCBs and PBDEs were investigated. The results showed that the concentrations of PCDD/Fs and PCBs decreased with increasing distance from the emission source and that different sampling sites had slightly different effects. However, this trend was opposite to that observed for PBDEs. Moreover, principal component analysis (PCA) demonstrated that the MSWI emission source was the primary factor for PCDD/Fs in ambient air. Further monitoring should be conducted to evaluate the noticeable impact on the environment and human health due to exposure.

Multiple classes of chemical contaminants in soil from an e-waste disposal site in China: Occurrence and spatial distribution.

E-waste recycling is well known for releasing halogenated organic compounds (HOCs) and heavy metals. This study investigated the occurrence and distribution of traditional and novel classes of contaminants, including chlorinated, brominated, and mixed halogenated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs, PBDD/Fs, PXDD/Fs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) and polyhalogenated carbazoles (PHCZs), in soil from an e-waste disposal site in Hangzhou. PBDEs were the most abundant, at 343-69306 ng kg-1, followed by PHCZs (896-41,362 ng kg-1), PCDD/Fs (349-19,396 ng kg-1), PCBs (51.3-1834 ng kg-1), PBDD/Fs (2.99-524 ng kg-1) and PXDD/Fs (0.104-21.2 ng kg-1). The detected target compound concentrations were generally lower than those reported in the literature for informal e-waste sites. Nevertheless, they can serve as a basis of information for evaluation and subsequent control. The toxic equivalent (TEQ) contributions from these contaminants (except PBDEs) decreased as follows: PCDD/Fs > PXDD/Fs > PHCZs > PCBs > PBDD/Fs. ΣDioxins (PCDD/Fs + PBDD/Fs + PXDD/Fs) accounted for 47.7%-97.2% of the total TEQs in the soil. OCDD, 1,2,3,4,6,7,8-HpBDF and OBDF were the dominant congeners, mainly derived from combustion and transport because of their low saturated vapor pressure. PXDFs were more abundant than PXDDs, and homologue profiles suggested a similar formation mechanism for PXDFs and PBDFs involving successive Br-to-Cl exchange. PHCZs were reported in soil from an e-waste disposal area for the first time, and their concentrations were several orders of magnitude higher than those of the other contaminants. Although the risk of human exposure in this study was estimated to be lower than the values recommended by the WHO (1-4 pg TEQ/kg bw/day), health implications still exist, and further investigations are necessary.