Itemized determination of As, Sb, Bi, Se, and Ge in graphite sample by HG-AFS with high-temperature microwave digestion.

In this paper, we optimized a method for fast and accurate determination of five impurity elements (As, Sb, Bi, Se, and Ge) in graphite samples to overcome the shortcomings of existing methods, such as complicated equipment, cumbersome process, multiple-time preparation, separate determination, and large error in results. Graphite samples were digested with HNO3-H2SO4-HClO4-HF in a high-temperature and high-pressure microwave digestion apparatus, and the elements were extracted and determined separately by AFS (atomic fluorescence spectrometry). There is no element loss during the processing and analysis of this method. The spike recoveries (As: 90.30%-102.3%, Sb: 90.73%-110.0%, Bi: 90.00%-99.67%, Se: 93.33%-110.0%, Ge: 92.26%-104.2%) and precision (RSD%; As: 1.34%-8.96%, Sb: 2.67%-7.10%, Bi: 1.83%-4.58%, Se: 0.36%-3.25%, Ge: 4.41%-8.65%) meet the requirements of the corresponding quality specifications. The method has some advantages (such as no elemental loss, fast testing, strong element targeting, and accurate results), and thus can achieve batch determination of graphite samples. The optimized method for graphite sample and final solution preparations can be used for diverse spectrometric technologies, and that for spectrometer conditions have reference value for HG-AFS instruments.

Diagnosis of invasive pulmonary aspergillosis by lateral flow assay of galactomannan in bronchoalveolar lavage fluid: a meta-analysis of diagnostic performance.

The performance of lateral flow assay (LFA) in diagnosing invasive pulmonary aspergillosis (IPA) has not been well demonstrated. To address this, we conducted a meta-analysis assessing the overall accuracy of LFA in diagnosing IPA using bronchoalveolar lavage fluid (BALF). Over a systematical search and assessment of bias risk, we calculated the pooled specificity, sensitivity, and area under the receiver operating curve (AUC) to assess the diagnostic performance. Our meta-analysis included 11 studies. The combined total sensitivity and specificity for diagnosing IPA were 0.78 (95% confidence interval (CI): 0.71, 0.83) and 0.87 (95% CI: 0.81, 0.91), respectively. The AUC was 0.86 (95% CI: 0.82, 0.89). Our results demonstrate that LFA using galactomannan in BALF exhibits high sensitivity and specificity for diagnosing IPA.

Working from anywhere: yin-yang cognition paradoxes of knowledge sharing and hiding for developing careers in China.

Digital technology coupled with the quarantines caused by the COVID-19 pandemic has made working from anywhere (WFA)-a modern form of remote working-a widespread phenomenon. Given that WFA brings new career challenges to and engenders paradoxes of knowledge exchange among employees, this research aims to examine how the interactions of remote work time (RWT), knowledge sharing (KS), and knowledge hiding (KH) affect career development (CD) from a culturally grounded paradoxical framing of yin-yang harmonizing. The data were collected from Chinese manufacturing employees, and a moderated hierarchical regression analysis was used to examine the hypotheses. The results show an inverted U-shaped relationship between RWT and CD. The interaction of KS and KH is significantly related to CD, and the inverted U-shaped RWT-CD relationship is moderated by the interaction term, in which RWT exerts the most substantial positive impact on CD when KS is high and KH is low. This study offers valuable implications for coping with perplexing employment relationships and increasing career challenges in volatile work environments. The primary originality is to adopt a novel cognitive frame of yin-yang harmonizing to examine the nonlinear effect of remote working and the symbiotic impact of KS and KH on CD, which not only enriches the understanding of flexible work arrangements in the digital economy but also provides novel insights into the interconnectedness of KS and KH and their interacting effects on HRM-related outcomes.

Residue level, occurrence characteristics and ecological risk of pesticides in typical farmland-river interlaced area of Baiyang Lake upstream, China.

Baiyang Lake is the largest freshwater lake in North China, playing an important role in aquatic products production and eco-environment improvement. Traditional organochlorine pesticides were not enough to reflect ecological risk. We performed the high-throughput and non-targeted screening to identify the high-residue and wide-distribution pesticides at farmland-river interlaced area. We firstly reported the residue level and spatio-temporal distribution of typical pesticides in soils and waters (SP1-SP13) near Fuhe river in 2020-2021. The mean recoveries of eight pesticides ranged from 79.4 to 129%. The residues were 0.250-3530 ng/L (water) and 2.79 × 10-3-647 µg/kg dw (soil), respectively. Thiamethoxam was dominant with the high-residue proportion (HRP) of 53-95% (water, HRP > 50%) and 63-97% (soil, HRP > 60%), respectively. Most of pesticides almost have no significant season-change. The risk quotient (RQ) model results showed that although most pesticides have no aquatic risk (RQ < 0.01), carbendazim and propionazole deserved attention. The individual thiamethoxam at nearly half of the sites exhibited high terrestrial risk (RQ, 1.070-1.682), while propiconazole was at medium risk (SP1, SP2, SP8, and SP9) and high risk (SP12). The RQall were in the range of 0.4541-3.327 (earthworm), 0.0239-0.4552 (algae), 0.1094-1.103 (aquatic invertabrates), and 0.1657-1.923 (fish), respectively, so co-residue caused joint toxic effect to aquatic invertebrates.

Reaction Behavior and Influencing Mechanisms of Different Fly Ashes on the NO Removal by Using the Ultraviolet Irradiating Chlorite Method.

Our previous work had demonstrated that UV/NaClO2 was the best advanced oxidation method in terms of nitric oxide (NO) removal, but we have not studied the impact of the fly ash on NO removal under such conditions. For this, this paper selected six kinds of fly ashes and studied their effects on NO removal. The micromorphology, elemental composition, and the elemental oxidation states of these six fly ashes were characterized by scanning electron microscopy-energy-dispersive X-ray spectra, X-ray photoelectron spectroscopy, and inductively coupled plasma methods. The main inorganic components in the six fly ashes are metal oxides (Fe2O3/Fe3O4, SiO2, Al2O3, ZnO, MgO, and TiO2), carbonates (Na2CO3 and CaCO3), and chlorides (NaCl, KCl, and MgCl2). The experimental results suggested that high solubility was the premise condition for the fly ashes exhibiting an inhibitory effect on NO removal. Among all of the metal compounds, Fe2O3/Fe3O4 exhibited the highest inhibitory contribution rate to the NO removal (22.9-45.7%). The anions of Cl- and CO3 2- acted as scavengers for the free radicals which greatly impaired the oxidation of NO. Based on the simulation experimental results and the UV-vis analysis, the order of inhibitory contribution rates of various metal compounds to the NO removal was determined as Fe2O3/Fe3O4 > TiO2 ≈ Na2CO3 > Al2O3 ≈ ZnO ≈ MnO2 > CaCO3 > NaCl > KCl ≈ SiO2 ≈ MgCl2.

Optimization of Lithium Metaborate Fusion and Post-ultrasonic Extraction for Multi-element Determination in Graphite by ICP-AES.

Existing methods can not achieve rapid mass decomposition and multi-element analysis of graphite ore samples. In this study, it is found that molten lithium metaborate can destroy the structure of graphite, causing graphite C to be oxidized and decomposed in an oxygen environment. We have established a method for testing graphite ore samples with lithium metaborate at 950°C with melting-ultrasonic extraction-ICP-AES multi-element (Al, Ca, Fe, K, Mg, Mn, Na, P, Si, and Ti) testing. The verification results of the national first-level reference materials show that the detection limit of this method is low and the accuracy and precision are good. The results of the measured samples show no significant difference between this method and the classical chemical analysis method. This method has the following advantages over the existing ones: simple operation process, faster decomposition and testing, low reagent consumption, reduced possibility of sample contamination, and better results reproducibility.