RESUMO
Negative temperature coefficient (NTC) thermistors feature higher sensitivities and faster response speeds and thereby have particular applications in many fields. However, current NTC thermistors are mostly based on inorganic ceramic materials, which show obvious drawbacks in material synthesis, property modulation, and flexible film fabrication. Herein, we report, for the first time, the promising application of an inorganic-organic hybrid NTC thermistor. A new lead-free hybrid iodo bismuthate [1,1',1â³-(benzene-1,3,5-triyl)tris(3-methyl-1H-imidazol-3-ium)]Bi2I9 [denoted as (Me3TMP)Bi2I9] was synthesized by a "double-free" strategy. (Me3TMP)Bi2I9 features a lead-free binuclear bismuth iodine anion charge compensated by a "classic hydrogen-bond-free" cation. (Me3TMP)Bi2I9 exhibits remarkable stability in water and UV light irradiation and shows the largest temperature sensitivity coefficient among all reported NTC materials. Theoretical calculation and detailed structural analysis disclose that the seriously distorted (BiI6) octahedra are responsible for the intriguing NTC effect for (Me3TMP)Bi2I9.
RESUMO
Trace element contamination caused by mining is a serious environmental problem. The potential effects of exploiting the Yunfu pyrite mine (southern China) on soil were investigated by determining trace elements in 56 surface soil samples from the vicinity of the Yunfu pyrite mine. The samples were acid dissolved and measured by an inductively coupled plasma mass spectrometry (ICP-MS). Principal component analysis and hierarchical cluster analysis were used to identify factors influencing the trace element contents and possible sources of the trace elements. The degree of trace element pollution was determined using the geological accumulation index Igeo. Monte Carlo simulations were used to assess the health risks posed. The results show that (1) six factors (parent material, mining activities, ore composition, rainfall, terrain, and other inputs) strongly affected the trace element contents of the soil samples. (2) There were three groups of trace elements, according to their possible sources. One group (Cs, Ga, Ge, Hf, Nb, Rb, Ta, Th, Ti, U, and Zr) mainly originated in parent rocks. Another group (Cr, Ni, Sr, and V) was mainly supplied by industrial plants and traffic emissions. The third group (Ba, Co, Cu, Mn, Pb, and Zn) was mainly supplied through pyrite ore exploitation processes. (3) Some samples were slightly to moderately polluted with Cs, Ga, Ge, Nb, Rb, Ta, and Ti. Most samples were moderately to highly polluted with Ba, Co, Cu, Mn, Pb, and Zn. (4) Trace elements in soil pose strong non-carcinogenic and carcinogenic health risks to people (particularly children) living near the Yunfu pyrite mine.
Assuntos
Monitoramento Ambiental/métodos , Metais Pesados/análise , Poluentes do Solo/análise , Oligoelementos/análise , Criança , China , Humanos , Ferro , Mineração , Solo/química , SulfetosRESUMO
BACKGROUND: Assessment of the risk of pesticide inhalation in populations around farmland is necessary because inhalation is one of the ways in which pesticides can risk human health. This study aimed to identify the inhalation risk of difenoconazole on humans by using dose-response and exposure assessments. RESULTS: In the field simulation application, respiratory exposure in populations around farmland ranged from 71 to 430 ng/m3 . Using response surface methodology, the maximum bioaccessibility of difenoconazole in three simulated lung fluids was 35.33% in Gamble's solution (GS), 34.12% in artificial lysosomal fluid (ALF), and 42.06% in simulated interstitial lung fluid (SLF). Taking the proliferation activity of the A549 cell model as the endpoint, the benchmark dose limit and benchmark dose of difenoconazole on A549 cells were 16.36 and 5.60 mg/kg, respectively. The margin of exposure to difenoconazole in GS, ALF and SLF were, respectively, 8.66 × 105 to 5.28 × 106 , 8.97 × 105 to 5.47 × 106 and 7.28 × 105 to 4.44 × 106 . CONCLUSION: The risk assessment results indicate that under all circumstances, applying difenoconazole is safe for populations around farmland. However, a fan-shaped nozzle, suspension concentrate and greater inhalation height increase the risk of inhalation. © 2023 Society of Chemical Industry.
Assuntos
Dioxolanos , Exposição por Inalação , Material Particulado , Triazóis , Humanos , Material Particulado/análise , Exposição por Inalação/análise , Medição de Risco , AtmosferaRESUMO
We report the thinnest copper sulfur atomic monolayer in an organic copper chalcogenide [Cu(CMP)]n (CMP = 5-chloro-2-mercaptopyridine). The layer features a new type of copper sulfur structure woven by both covalent bond and cuprophilic interaction and shows an intriguing oriented photoconductivity.
RESUMO
Background and Aims: Studies have indicated that serum von Willebrand factor (vWF) has a positive correlation with hepatic venous pressure gradient. However, information on the value of vWF in the diagnosis of liver cirrhosis with portal hypertension has been lacking. The purpose of this meta-analysis was to assess the value of vWF in the diagnosis of liver cirrhosis with portal hypertension. Methods: Studies that analyzed the sensitivity, specificity, diagnostic odds ratio combined with likelihood ratios and test for heterogeneity of vWF in the diagnosis of liver cirrhosis with portal hypertension were found in the Cochrane Library, Ovid, VOS-SCI, CNKI, PubMed, Medline, EMBASE, CMB and Wanfang databases. In the end, the data was used to draw the summary receiver operating characteristic curve and to calculate the area under the curve. Results: Four studies involving 662 patients were analyzed. The results showed that serum vWF in liver cirrhosis with portal hypertension were significantly higher than in those without portal hypertension. Sensitivity combined was 0.823 (95% CI: 0.788, 0.855). Specificity combined was 0.782 (95% CI: 0.708, 0.845). +LR combined was 3.777 (95% CI: 2.794, 5.107). -LR combined was 0.221 (95% CI: 0.180, 0.272). Diagnostic odds ratio combined was 18.347 (95% CI: 11.725, 28.708). The area under the curve was 0.8896. Conclusions: Serum vWF can be used as an effective and feasible method for noninvasive diagnosis of liver cirrhosis with portal hypertension. However, further studies are still needed to evaluate the severity of liver cirrhosis with portal hypertension.