Mercury-Mediated Epitaxial Accumulation of Au Atoms for Stained Hydrogel-Improved On-Site Mercury Monitoring

Trivalent Au ions are easily reduced to be zerovalent atoms by coexisting reductant reagents, resulting in the subsequent accumulation of Au atoms and formation of plasmonic nanostructures. In the absence of stabilizers or presence of weak stabilizers, aggregative growth of Au nanoparticles (NPs) always occurs, and unregular multidimensional Au materials are consequently constructed. Herein, the addition of nanomole-level mercury ions can efficiently prevent the epitaxial accumulation of Au atoms, and separated Au NPs with mediated morphologies and superior plasmonic characteristics are obtained. Experimental results and theoretical simulation demonstrate the Hg-concentration-reliant formation of plasmonic nanostructures with their mediated sizes and shapes in the presence of weak reductants. Moreover, the sensitive plasmonic responses of reaction systems exhibit selectivity comparable to that of Hg species. As a concept of proof, polymeric carbon dots (CDs) were used as the initial reductant, and the reactions between trivalent Au and CDs were studies. Significantly, Hg atoms prevent the epitaxial accumulation of Au atoms, and plasmonic NPs with decreased sizes were in situ synthesized, corresponding to varied surface plasmonic resonance absorption performance of the CD-induced hybrids. Moreover, with the integration of sensing substrates of CD-doped hydrogels, superior response stabilities, analysis selectivity, and sensitivity of Hg2+ ions were achieved on the basis of the mercury-mediated in situ chemical reactions between trivalent Au ions and reductant CDs. Consequently, a high-performance sensing strategy with the use of Au NP-staining hydrogels (nanostaining hydrogels) was exhibited. In addition to Hg sensing, the nanostaining hydrogels facilitated by doping of emerging materials and advanced chem/biostrategies can be developed as high-performance on-site monitoring routes to various pollutant species.

Tracking the Growth of Chiral Plasmonic Nanocrystals at Molybdenum Disulfide Heterostructural Interfaces

The way of accurately regulating the growth of chiral plasmonics is of great importance for exploring the chirality information and improving its potential values. Herein, cysteine enantiomers modulate the anisotropic and epitaxial growth of gold nanoplasmonics on seeds of exfoliated MoS₂ nanosheets. The heterostructural Au and MoS₂ hybrids induced by enantiomeric cysteine are presented with chiroptical characteristics, dendritic morphologies, and plasmonic performances. Moreover, the synthesis, condition optimization, formation mechanism, and plasmonic properties of Au and MoS₂ dendritic nanostructures are studied. The chirality characteristics are identified using the circular dichroism spectra and scanning electron microscopy. Time-resolved transmission electron microscopy and UV-vis spectra of the intermediate products captured are analyzed to confirm the formation mechanism of dendritic plasmonic nanostructures at heterostructural surfaces. The specific dendritic morphologies originate from the synergistic impacts of heterostructural MoS₂ interfaces and enantiomeric cysteine-induced anisotropic manipulation. Significantly, the developed synthesis strategy of chiral nanostructures at heterostructural interfaces is highly promising in promoting the understanding of the plasmonic function and crucial chirality bioinformation.

Chiral nanocrystals grown from MoS2 nanosheets enable photothermally modulated enantioselective release of antimicrobial drugs

The transfer of the concept of chirality from molecules to synthesized nanomaterials has attracted attention amongst multidisciplinary teams. Here we demonstrate heterogeneous nucleation and anisotropic accumulation of Au nanoparticles on multilayer MoS₂ planes to form chiroptically functional nanomaterials. Thiol amino acids with chiral conformations modulate asymmetric growth of gold nanoarchitectures on seeds of highly faceted Au/MoS₂ heterostructures. Consequently, dendritic plasmonic nanocrystals with partial chiral morphologies are synthesized. The chirality of dendritic nanocrystals inherited from cysteine molecules refers to the structural characteristics and includes specific recognition of enantiomeric molecules. With integration of the intrinsic photothermal properties and inherited enantioselective characteristics, dendritic Au/MoS₂ heterostructures exhibit chirality-dependent release of antimicrobial drugs from hydrogel substrates when activated by exogenous infrared irradiation. A three-in-one strategy involving synthesis of chiral dendritic heterostructures, enantioselective recognition, and controlled drug release system is presented, which improves nanomaterial synthetic technology and enhances our understanding of crucial chirality information.

[Analysis of 1153 Cases of Forest Encephalitis Reported by Domestic Documents]

Objective: To summarize the clinical characteristics, diagnosis and treatment of forest encephalitis, and provide basis for revising relevant diagnostic criteria. Methods: From January to December 2020, the clinical characteristics, diagnosis and treatment of forest encephalitis cases in the data of China National Knowledge Infrastructure (CNKI) and Wanfang Chinese journals from 2009 to 2020 were retrospectively analyzed. The measurement data are expressed in Mean±SD, numbers, and the counting data of gender, region and occupation are expressed in numbers and composition ratio. Descriptive analysis of relevant data is carried out. Results: There were 1 153 confirmed cases of forest encephalitis reported in domestic literature, including 910 males and 243 females. Age: 16-78 years old; Cases were mainly distributed in Jilin Province, Inner Mongolia Autonomous Region and Heilongjiang Province. The cases included forest rangers (112/518), freelancers (104/518) and loggers (88/518). The common symptoms and signs were fever 81.2% (936/1153), headache 70.3% (811/1153), meninges irritation 29.0% (334/1153), vomiting 25.3% (292/1153), nausea 21.8% (251/1153), etc. Only 48.1% (555/1153) of the patients obtained positive pathogenic test results from blood and/or cerebrospinal fluid specimens. 42.1% (485/1153) had definite diagnosis grade, 354 cases were mild, 58 cases were moderate, and 73 cases were severe. Among 730 patients with forest encephalitis who received complete treatment, 511 cases were cured, 148 cases were improved, 48 cases were not cured, and 23 cases died. Conclusion: The epidemic of forest encephalitis has strict regional, seasonal and occupational characteristics. Early diagnosis and treatment can reduce the mortality and disability rate.

[Evaluation of the implementation of Diagnostic Criteria of Occupational Acute Neurotoxic Diseases Caused by Chemicals (GBZ 76-2002)]

Objective: To investigate the implementation of Diagnostic Criteria of Occupational Acute Neurotoxic Diseases Caused by Chemicals (GBZ 76-2002) for accumulating basis of standard revision. Methods: In February 2020, 85 experts in occupational diseases and neurology from 39 medical and health institutions were selected as the respondents. The modified Delphi method was used to establish the standard evaluation index system and special group was organized for discussing the pre-survey and completing the questionnaire survey. Questionnaire survey was performed to investigate the grasp of the standards, application and modification suggestions of respondents. Results: The respondents' mastery of standard-related knowledge mainly came from work experience (84.7%, 72/85) , standard learning (81.2%, 69/85) and training (75.3%, 64/85) . Among the institutions in which the respondents worked, 98.8% (84/85) could carry out CT examinations, 96.5% (82/85) could carry out nerve conduction velocity and electromyography examinations, 89.4% (76/85) could carry out EEG examinations, 80% (68/85) could carry out evoked potential examinations and 72.9% (62/85) could carry out MRI examinations. Among the toxicants diagnosed as occupational acute toxic myelopathy, 10.6% (9/85) were organic phosphorus and 9.4% (8/85) were asphyxiating gas; Among the toxicants diagnosed as delayed peripheral neuropathy, pesticides accounted for 25.9% (22/85) and asphyxiating gases accounted for 12.9% (11/85) . 85.9% (73/85) of the respondents believed that the basis for the classification of acute toxic encephalopathy needed to supplement objective evidence; 80.0% (68/85) of the respondents thought that the diagnosis and classification of peripheral neuropathy should be refined according to the abnormal indexes of neuroelectromyography. Conclusion: The applicability of the criteria needs to be improved because the current criteria has a long application cycle without enough objective investigation bases in classification criteria index.

[The application of narrative therapy in convalescent patients with occupational acute chemical toxic encephalopathy]

Objective: To explore the effects of narrative therapy on cognition, emotion and treatment satisfaction of convalescent patients with occupational acute chemical toxic encephalopathy. Methods: From June to July 2019, 60 convalescent patients with occupational chemical poisoning encephalopathy were randomly divided into narrative group and control group, with 30 cases in each group. The control group received routine clinical treatment. On the basis of receiving the original clinical treatment, patients in the narrative group added narrative treatment once a week to explain discomfort in specific life situations through conversation from the perspective of disease and psychology. 30 min each time for 6 weeks. The patients were investigated with Montreal Cognitive Assessment Scale (MoCA scale) every 2 weeks to evaluate the degree of cognitive impairment. The changes of depression, anxiety and treatment satisfaction were investigated before and after intervention. Results: There was no significant difference in MoCA scores between the two groups before intervention (P>0.05) . After 6 weeks of treatment, MoCA scores of narrative group and control group gradually increased with the extension of treatment time, and the increase degree of MoCA score of narrative group was greater than that of control group (P<0.01) . Before intervention, there was no significant difference in depression, anxiety score, prevalence and satisfaction index between narrative group and control group (P>0.05) . After the intervention, the scores and prevalence of depression and anxiety in the narrative group were significantly lower than those in the control group, and the scores of feeling in the process of seeing a doctor and how to obtain their own disease information were significantly higher than those in the control group (P<0.05) . Conclusion: Narrative therapy can improve the cognitive function and emotion of patients with occupational chemical poisoning, and improve the treatment satisfaction of patients.

Layered MoS2 defect-driven in situ synthesis of plasmonic gold nanocrystals visualizes the planar size and interfacial diversity

Current defect theories significantly guide broad research progress, whereas the recognition of defect status remains challenging. Herein, MoS2 defect type, density and exposed state are visually identified with a reagent indicator of HAuCl4. Mo-terminated defects spontaneously reduce [AuCl4]- anions and oxidized Mo species are dissociated. Consequently, MoS2 edges guide the epitaxial branch of Au nanocrystals (NCs), followed by sequential growths at their planar defects. The size-evolution processes of LaMer growth and planar packages of the aggregative growth of Au/MoS2 nanoseeds result in the occupation of Au atomic layers on heterostructures. Consequently, shell-core hybrids are presented with localized surface plasmon resonance characteristics. The mechanism is systematically explored via the discriminated performance of plasmonic characteristics of Au nanostructures on semiconducting MoS2 substrates. With plasmonic identification, defect-associated size and interfacial diversities of MoS2 are visually information-rich. Tunable morphologies and synergistic optical characteristics of plasmonic semiconductor heterostructures inspire many more applications through the edge and planar defects intrinsic in layered MoS2.

Layered Aggregation with Steric Effect: Morphology-Homogeneous Semiconductor MoS2 as an Alternative 2D Probe for Visual Immunoassay

Liquid-phase exfoliation routes unavoidably generate 2D nanostructures with inhomogeneous morphologies. Herein, thickness-dependent sorting of exfoliated nanostructures is achieved via a treatment of differential-zone centrifugation in the surfactant aqueous phase. With this approach, homogeneous MoS₂ nanosheets are obtained, and due to the intrinsic semiconducting characteristics, those 2D nanosheets are endowed with desired optical properties, rivaling classic gold nanoparticles in sensing applications. Furthermore, MoS₂ nanosheets with high uniformity and chemical inertness are coupled with proteins, exhibiting high performance in stability and anti-interferences for bioanalysis. As a consequence of aggregation-induced steric effect, distinguishing running shifts of antibody-anchored conjugates in gel electrophoresis are visually responsive to those specific antigens. This assay enables the easy and fast monitoring of tumor biomarkers just according to "naked-eye" identification of band location in electrophoresis results, which are presented by an alternative visual probe of 2D MoS₂ -protein conjugates. The developed visual immunoassay with the synergistic effect of gel electrophoresis techniques and 2D semiconductors pushes significant progress in "home-made" tests for disease early diagnosis.

Emerging 0D Transition-Metal Dichalcogenides for Sensors, Biomedicine, and Clean Energy

Following research on two-dimensional (2D) transition metal dichalcogenides (TMDs), zero-dimensional (0D) TMDs nanostructures have also garnered some attention due to their unique properties; exploitable for new applications. The 0D TMDs nanostructures stand distinct from their larger 2D TMDs cousins in terms of their general structure and properties. 0D TMDs possess higher bandgaps, ultra-small sizes, high surface-to-volume ratios with more active edge sites per unit mass. So far, reported 0D TMDs can be mainly classified as quantum dots, nanodots, nanoparticles, and small nanoflakes. All exhibited diverse applications in various fields due to their unique and excellent properties. Of significance, through exploiting inherent characteristics of 0D TMDs materials, enhanced catalytic, biomedical, and photoluminescence applications can be realized through this exciting sub-class of TMDs. Herein, we comprehensively review the properties and synthesis methods of 0D TMDs nanostructures and focus on their potential applications in sensor, biomedicine, and energy fields. This article aims to educate potential adopters of these excitingly new nanomaterials as well as to inspire and promote the development of more impactful applications. Especially in this rapidly evolving field, this review may be a good resource of critical insights and in-depth comparisons between the 0D and 2D TMDs.

Recycling agriculture wastes of ramie stalk as bioadsorbents for Cd(2+) removal: a kinetic and thermodynamic study

In this study, we exhibit the recycling of agriculture wastes of ramie stalk as bioadsorbents for Cd(2+) removal. Based on our experimental results, it is realized that Cd(2+) adsorption to ramie stalk is highly pH sensitive, indicating the adsorption is driven by surface complexation reaction. The high adsorption capacity of ramie stalk toward Cd(2+) (qm = 10.33 mg g(-1), 0.09 mol-Cd g(-1)), which corresponds to around 21.95% of active adsorption sites available of ramie stalk, is believed to be closely related to its high cellulose and lignin content. The inhomogeneous surface of ramie stalk due to the high cellulose and lignin content also accounts for the observation that the adsorption kinetic is described well by the pseudo second order kinetic model. Results from thermodynamic studies suggest that the adsorption process is endothermic and spontaneous. All these properties demonstrate the potential of ramie stalk as a low cost bioadsorbent for the application of heavy metal removal.

Electrochemically induced Fenton reaction of few-layer MoS2 nanosheets: preparation of luminescent quantum dots via a transition of nanoporous morphology

Electrochemically induced Fenton (electro-Fenton) reaction was used for efficient and controllable preparation of hydroxyl radicals, leading to the generation of luminescent quantum dots through etching of as-exfoliated MoS2 nanosheets. Morphologic changes of MoS2 nanosheets during the electro-Fenton reaction were monitored using transmission electron microscopy, showing that etching of MoS2 nanosheets induced by hydroxyl radicals resulted in rapid homogeneous fracturing of the sheets into small dots via a transition of nanoporous morphology. The as-generated dots with vertical dimensional thickness of ca. 0.7 nm and plane size of ca. 5 nm were demonstrated to be MoS2 quantum dots (MoS2-QDs), and their photoluminescence properties were explored based on quantum confinement, edge effect, and intrinsic characteristics. Moreover, the degree of etching and the concomitant porosity of MoS2 nanosheets could be conveniently tuned via the electro-Fenton reaction time, resulting in a new morphology of nanoporous MoS2 nanosheets, with potential new applications in various significant areas.

Zinc and cadmium accumulation and tolerance in populations of Sedum alfredii

To investigate the variation of Zn and Cd accumulation and tolerance of Sedum alfredii (a newly reported Zn/Cd hyperaccumulator), field surveys and hydroponic experiments were conducted among three populations of this species: two originating from old Pb/Zn mines in Zhejiang (ZJ) and Hunan (HN) Provinces and one from a "clean" site in Guangdong (GD) Province, China. Under field conditions, up to 12,524 and 12,253 mg kg(-1) Zn, and 1400 and 97 mg kg(-1) Cd in shoots of ZJ and HN plants were recorded respectively. Under hydroponic conditions, ZJ and HN plants accumulated significantly higher Zn and Cd in their leaves and stems, and possessed significantly higher Zn and Cd tolerance than GD plants. Among the two contaminated populations, ZJ plants showed higher Cd tolerance and accumulation (in leaves) than HN plants. The present results indicate that significant differences in Zn and Cd accumulation and tolerance exist in populations of S. alfredii.