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Reactive sulfur species (RSS) and reactive selenium species (RSeS) play integral roles in hydrogen sulfide (H2S) and hydrogen selenide (H2Se) biological signaling pathways, and dichalcogenide anions are proposed transient intermediates that facilitate a variety of biochemical transformations. Herein we report the selective synthesis, isolation, spectroscopic and structural characterization, and fundamental reactivity of persulfide (RSS–), perselenide (RSeSe–), thioselenide (RSSe–), and selenosulfide (RSeS–) anions. The isolated chalcogenides do not rely on steric protection for stability and have steric profiles analogous to cysteine (Cys). Simple reduction of S8 or Se by potassium benzyl thiolate (KSBn) or selenolate (KSeBn) in the presence of 18-crown-6 afforded [K(18-crown-6)][BnSS] (1), [K(18-crown-6)][BnSeSe] (2) [K(18-crown-6][BnSSe] (3), and [K(18-crown-6][BnSeS] (4). The chemical structure of each dichalcogenide was confirmed by X-ray crystallography and solution state 1H, 13C, and 77Se NMR spectroscopy. To advance our understanding of the reactivity of these species, we demonstrated that reduction of 1-4 by PPh3 readily generates E=PPh3 (E: S, Se), and reduction of 1, 3, and 4 by DTT readily produces HE–/H2E. Furthermore, 1-4 reacts with CN– to produce ECN–, which is consistent with the detoxifying effects of dichalcogenide intermediates in the Rhodanese enzyme. Taken together, this work provides new insights into the inherent structural and reactivity characteristics of dichalcogenides relevant to biology and advances our understanding of the fundamental properties of these reactive anions.

Squalene, as an important terpenoid, is extensively used in the medicine and health care fields owing to its functions of anti-oxidation, blood lipid regulation and cancer prevention. The marine microalgae, Schizochytrium sp., which acts as an excellent strain with potential of high squalene production was selected as the starting strain. The overexpressed strain with sqs gene got the reduced biomass and lipid, while the squalene titer was increased by 79.6% ± 4.7% to 12.8 ± 0.2 mg/L. In order to further increase squalene production, the recombinant strain (HS strain) with sqs and hmgr gene co-overexpression was further constructed. The biomass and squalene titer of the HS strain were increased by 13.6% ± 1.2% and 88.8% ± 5.3%, respectively, which indicated the carbon flux of the mevalonate pathway was enhanced for squalene accumulation. Regarding the squalene synthesis is completely coupled with cell growth, fermentation strategy to prolong the logarithmic growth phase was conducive to improve squalene production. Under the condition of optimal composition and concentrated medium, the squalene titer of HS strain was 27.0 ± 1.3 mg/L, which was 2.0 times that of the basal medium condition (13.5 ± 0.4 mg/L). This study which combined the metabolic engineering and fermentation strategy provides a new strategy for squalene production in Schizochytrium sp. KEY POINTS: •The overexpression of sqs and hmgr genes promoted carbon metabolism for squalene. •The optimal and concentrated media can increase squalene yield.

Reactions of the electron rich PhB(tBuIm)3ZnCl complex with n-BuLi and [K.18-C-6]2[S4] lead to the formation of the carbon-rich coordination complex PhB(tBuIm)3ZnBu and the tetrahedral tetrasulfido complex PhB(tBuIm)2(tBuImH)Zn(κ2-S4), respectively.

Porous carbon nitride with rich amino defects shows excellent photocatalytic activity for synergistic removal of organic and heavy metal pollutants.

An S-scheme heterojunction is constructed with α-Fe2O3 nanoparticles and In–CN nanosheets as a highly efficient photocatalyst for CO2 reduction.

Realizing high-efficiency solar-driven CO2 reduction to chemicals and fuels requires high-performance photocatalysts with high utilization efficiency of solar light, efficient charge separation and transfer, and robust adsorption capacity for CO2. In this work, a tubular In2O3-C/CdIn2S4 (IOC/CIS) ternary heterojunction with an intimate interfacial contact was fabricated by pyrolysis of In-MIL-68 and subsequent solvothermal synthesis of CdIn2S4. The construction of a heterojunction promotes the separation and transfer efficiency of photogenerated carriers. The introduction of carbon not only accelerates the interfacial charge migration but also enhances light absorption and CO2 adsorption. The resulting 5IOC/CIS sample presents a remarkably improved photocatalytic CO2 reduction activity with a CO generation rate of 2432 μmol g-1 h-1, much higher than that of the In2O3/CdIn2S4 (IO/CIS) heterojunction (1906 μmol g-1 h-1). Furthermore, the type II charge transfer mechanism of the heterojunction was confirmed by the electron paramagnetic resonance characterization. This work provides new insight into the design and preparation of a highly efficient hollow heterojunction for photocatalytic applications.

Visible light has shown to greatly enhance the activity of iron-doped semiconductor catalyst in a Fenton reaction system, however, the mechanism for this activity enhancement remains unclear. This work attempts to reveal the origin of this visible light driven activity enhancement by studying the iron doped semiconductor catalyst Fe/g-C3N4 in both photo-Fenton and dark Fenton reactions. Through analysis of XPS spectra of catalyst, it is found that Fe2+/Fe3+ ratio for Fe/g-C3N4 catalyst remains unchanged and sustained during the photo-Fenton reaction cycles. This is in direct contrast to the progressively decreased Fe2+/Fe3+ ratio observed in the dark Fenton reaction. It is clear that under visible light, Fe3+ is able to capture the photo-generated electrons from the semiconductor and revert back to Fe2+, thus sustain the catalytic activity during the photo-Fenton reaction. This new mechanistic insight will guide the future design and optimization of high performance catalysts by immobilizing transition metal ions in semiconductors for advanced oxidation processes.

The development of high-efficiency photocatalysts is of great importance to realize robust solar-driven CO₂ conversion; however, the low carrier separation efficiency and poor light absorption ability usually limit the performance of the photocatalysts. Herein, a hollow In₂S₃/polymeric carbon nitride (IS/CN) heterojunction was prepared via electrostatic self-assembly and in situ sulfidation under solvothermal conditions. The intimate interfacial contact between the IS and CN facilitates the construction of an effective heterojunction, as demonstrated by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The optimized IS/CN-5 sample exhibits a high CO evolution rate of 483.4 μmol g–¹ h–¹, which is 99 and 6 times as high as that of IS and CN, respectively. The improved charge separation and transfer efficiency, the hollow nanotube structure, and the enhanced CO₂ adsorption ability are the reasons for the excellent photocatalytic activity. Besides, a possible photocatalytic mechanism of CO₂ reduction by the IS/CN heterojunction was proposed on the basis of the band structures. This work provides an effective and facile strategy to construct hollow semiconductor heterojunctions for photocatalytic applications.

In this work, we present an in situ method to probe the evolution of photoelectrochemically driven surface oxidation on photoanodes during active operation in aqueous solutions. A standard solution of K4Fe(CN)6-KPi was utilized to benchmark the photocurrent and assess progressive surface oxidation on Ta3N5 in various oxidizing solutions. In this manner, a proportional increase in the surface oxygen concentration was detected with respect to oxidation time and further correlated with a continuous decline in the photocurrent. To discern how surface oxidation alters the photocurrent, we experimentally and theoretically explored its impact on the surface carrier recombination and the interfacial hole transfer rates. Our results indicate that the sluggish photocurrent demonstrated by oxidized Ta3N5 arises because of changes in both rates. In particular, the results suggest that the N-O replacement present on the Ta3N5 surface primarily increases the carrier recombination rate near the surface and to a lesser degree reduces the interfacial hole transfer rate. More generally, this methodology is expected to further our understanding of surface oxidation atop other nonoxide semiconductor photoelectrodes and its impact on their operation.

Early diagnosis is critical for the prevention and control of the coronavirus disease 2019 (COVID-19). We attempted to apply a protocol using teleultrasound, which is supported by the 5G network, to explore the feasibility of solving the problem of early imaging assessment of COVID-19. Four male patients with confirmed or suspected COVID-19 were hospitalized in isolation wards in two different cities. Ultrasound specialists, located in two other different cities, carried out the robot-assisted teleultrasound and remote consultation in order to settle the problem of early cardiopulmonary evaluation. Lung ultrasound, brief echocardiography, and blood volume assessment were performed. Whenever difficulties of remote manipulation and diagnosis occurred, the alternative examination was repeated by a specialist from another city, and in sequence, remote consultation was conducted immediately to meet the consensus. The ultrasound specialists successfully completed the telerobotic ultrasound. Lung ultrasound indicated signs of pneumonia with varying degrees in all cases and mild pleural effusion in one case. No abnormalities of cardiac structure and function and blood volume were detected. Remote consultation on the issue of manipulation practice, and the diagnosis in one case was conducted. The cardiopulmonary information was delivered to the frontline clinicians immediately for further treatment. The practice of teleultrasound protocol makes early diagnosis and repeated assessment available in the isolation ward. Ultrasound specialists can be protected from infection, and personal protective equipment can be spared. Quality control can be ensured by remote consultations among doctors. This protocol is worth consideration as a feasible strategy for early imaging assessment in the COVID-19 pandemic.

Magnetic anomaly detection is an effective method for detecting ferromagnetic targets. The practical application of target detection by measuring the magnetic gradient has been confirmed in many studies, and its suppression of background noise has been widely recognized. However, the variation of the unidirectional magnetic field gradient is very small in a short distance, and the amplitude of the signal is also affected by the direction of the target’s magnetic moment and the shaking of the sensor platform itself. These make it difficult to extract the signal from complex background interference. In order to solve these problems, this paper is devoted to use the variation of three axial magnetic gradients in the geomagnetic coordinate system caused by the presence of magnetic target (we call it full magnetic gradient) to construct the magnetic anomaly characteristic of the target. A set of orthonormal basis functions is further derived to linearly describe this characteristic, which improves the signal-to-noise ratio (SNR) of the signal from the perspective of signal energy. The present work main contribution is to propose a full magnetic gradient orthonormal basis function (FMG-OBF) method to effectively characterize magnetic anomaly of magnetic targets. Compared with the traditional one-direction magnetic gradient orthonormal basis function method, the SNR of this method is greatly improved, and it is not affected by a change in the target magnetic moment’s direction nor by the shaking of the sensor carrier platform. Therefore, it has great value in the practical application of aeromagnetic detection.

Heterogeneous catalysts with ultra-small clusters and atomically dispersed (USCAD) active sites have gained increasing attention in recent years. However, developing USCAD catalysts with high-density metal sites anchored in porous nanomaterials is still challenging. Here, through the template-free S-assisted pyrolysis of low-cost Fe-salts with melamine (MA), porous alveolate Fe/g-C3N4 catalysts with high-density (Fe loading up to 17.7 wt%) and increased USCAD Fe sites were synthesized. The presence of a certain amount of S species in the Fe-salts/MA system plays an important role in the formation of USCAD S-Fe-salt/CN catalysts; the S species act as a “sacrificial carrier” to increase the dispersion of Fe species through Fe-S coordination and generate porous alveolate structure by escaping in the form of SO2 during pyrolysis. The S-Fe-salt/CN catalysts exhibit greatly promoted activity and reusability for degrading various organic pollutants in advanced oxidation processes compared to the corresponding Fe-salt/CN catalysts, due to the promoted accessibility of USCAD Fe sites by the porous alveolate structure. This S-assisted method exhibits good feasibility in a large variety of S species (thiourea, S powder, and NH4SCN) and Fe salts, providing a new avenue for the low-cost and large-scale synthesis of high-density USCAD metal/g-C3N4 catalysts.

Objective: To investigate the value of lung ultrasound (LUS) in asymptomatic patients with confirmed COVID-19.Methods: A retrospective analysis was performed on nine patients in a designated isolation hospital in Sanya from February 22nd, 2020 to February 23rd, 2020. All patients were confirmed with COVID-19 pneumonia by PCR test, but none had the typical symptoms of COVID-19. All patients first underwent LUS examination and then chest computed tomography (CT) scanning. The application value of LUS in asymptomatic confirmed patients with COVID-19 was evaluated, compared with chest CT which was regarded as the golden standard.Results: Among nine asymptomatic patients with COVID-19, there were two cases (22.22%) with abnormal ultrasonic manifestations, of which one (11.11%) showed a fusion B3-line in zone 5 of the right lung, and the other showed localized pulmonary consolidation in zone 6 of the left lung. The remaining seven cases (77.78%) showed no abnormal changes in LUS, but only clear pleura sliding sign and A-line. Chest CT showed abnormal changes in three cases (33.33%). Two of them (22.22%) showed flocculent high-density shadow at the base of both lungs (especially in the right lung), while the other case showed ground-glass opacity with thickened interlobular septal in the left lower lobe, involving the pleura. There were no abnormalities on chest CT of the remaining six cases (66.67%). The two (22.22%) LUS-positive patients were in complete coincidence with CT-positive patients. This study showed that the coincidence rate of the two examination methods was 88.89%. Taking chest CT as golden standard, the sensitivity, specificity, positive predictive value, negative predictive value, and Kappa value of lung ultrasound in the diagnosis of COVID-19 were 66.67%, 100%, 100%, 85.71%, and 0.727, respectively.Conclusion: LUS can evaluate lung lesions in asymptomatic patients with COVID-19. Compared with chest CT, the diagnostic coincidence rate and diagnostic consistency of LUS are relatively higher. For this asymptomatic type of patient, ultrasound can be used as a diagnosis method, which can avoid the risk of radiation exposure in a short period of time. As a rapid and dynamic assessment method, LUS can cooperate with remote consultation to provide timely and accurate guidance for clinical diagnosis and treatment when necessary.

Low charge separation efficiency is the critical limitation for solar-driven CO2 conversion into chemicals fuels. Accelerating charge transfer in the interface of photocatalysts is an intriguing approach to suppress charge recombination. Herein, Co2+ doped 0D/2D TiO2 quantum dots confined in graphitic carbon nitride (CoTiCN) heterostructure was prepared by in-situ pyrolysis of MOFs and urea. Co2+ serves as the bridge of linking 0D TiO2 and 2D g-C3N4 in the interface, and consequently accelerates charge transfer in the interface from 2D g-C3N4 to 0D TiO2. As a result, CO evolution rate for photocatalytic CO2 reduction reached 290 μmol g−1 h−1, much higher than those of pure g-C3N4 and TiO2/g-C3N4. In addition, photocatalytic mechanism study indicates that [Co(bpy)3]Cl2 in the system functions as cocatalyst without any photocatalytic activity under visible light irradiation. Electron transfer occurs from heterogeneous photocatalyst to [Co(bpy)3]Cl2, which acts as the electron transporter as active sites to catalyze CO2 reduction into CO. This work provides an insight into the design of metal doped 0D/2D material towards visible light driven CO2 reduction from the viewpoint of promoting charge transfer in the interface and the understanding of the photocatalytic mechanism of cocatalyst in system.

Objectives. This study aimed to observe the relationship among heavy metals concentration, microsatellite instability (MSI), and human epidermal growth factor receptor type 2 (HER2) gene amplification in gastric cancer (GC) patients. Methods. The concentrations of 18 heavy metals in the plasma of GC patients and healthy controls were measured by inductive coupled plasma emission spectrometry (ICP-MS). MSI detection was conducted by detecting 5 microsatellite repeat markers by PCR analysis. HER2 gene amplification was detected by fluorescence in situ hybridization (FISH). The relationship among heavy metal elements, tumor biomarkers, HER2 amplification, and MSI status was analyzed by Pearson correlation analysis. Results. A total of 105 GC patients and 62 healthy controls were recruited in this study. The concentration of arsenic (As), chromium (Cr), cuprum (Cu), mercury (Hg), manganese (Mn), lead (Pb), stibium (Sb), selenium (Se), stannum (Sn), strontium (Sr), thallium (Tl), vanadium (V), and zinc (Zn) were significantly different between GC patients and controls. Among 105 GC patients, including 87 microsatellite-stable (MSS) samples and 18 MSI samples, the concentration of Ga is significantly higher in the MSI group than that in the MSS group. Meanwhile, in 97 GC patients having detected HER2 gene amplification, 69 of 97 had negative HER2 gene amplification and the rest 28 GC patients had positive HER2 gene amplification. The concentration of Hg, Sn, and Tl is noticeably higher in the HER2 positive group than in the HER2 negative group. Only Sb was positively correlated with MSI, but none of these heavy metals was correlated with HER2 gene amplification. Conclusions. The results indicated that Sb has significant positive correlation with the MSI status, which suggests that Sb may cause MSI in GC. However, further research studies are required to elucidate the mechanisms in the near feature.

Background In recent five years, China's special education has entered a stage of rapid development, but insufficient attention has been paid to the psychological game technology in special education. Therefore, this paper attempts to use the research method of social network analysis to analyze the application and research status of psychological game technology in special education in China. Subjects and Methods 204 papers such as CNKI journals, academic papers and conference papers are selected as the research object. The keywords in the research field of psychological game technology in special education are extracted by SATI 4.0 and Gephi0.9.2 to generate a high-frequency keyword matrix. Finally, based on the social network analysis method, the keyword network composed of all high-frequency keywords is analyzed through macro analysis, central analysis and community analysis. At the same time, the state trait anxiety questionnaire was used. This study uses the state trait anxiety questionnaire to investigate the general anxiety of receiving special education, and then obtains the correlation between special education groups and general state anxiety and trait anxiety. The theoretical basis of this questionnaire is the concepts of state anxiety and trait anxiety proposed by Catell and Spielberger. The former describes an unpleasant emotional experience, such as tension, fear, anxiety and neuroticism, accompanied by hyperfunction of the autonomic nervous system, which is generally transient. Trait anxiety is used to describe the relatively stable anxiety tendency, which is a personality trait and has individual differences. It was compiled in Chinese by Spielberger et al. In 1980, it was translated into Chinese by Spielberger et al. STAI is composed of 40 descriptive questions with guidance and two subscales. Items 1-20 are state anxiety scale (S-AI). Half of them are items describing negative emotions and half are items describing positive emotions. This is mainly used to evaluate the immediate or recent experience or feeling of fear, tension, anxiety and neuroticism. Items 21-40 are called trait anxiety scale (T-AI), which is used to evaluate people's frequent emotional experience. Among them, 11 items described negative emotions and 9 items described positive emotions. Each item of STAI was scored at level 1-4. S-ai: 1 - none at all, 2 - some, 3 - medium, 4 - very obvious. T-AI: 1, almost none, 2, some, 3, often, 4, almost always. The subjects choose the most appropriate score according to their own experience. All positive emotion items are scored in reverse. The cumulative scores of s-ai and T-AI scales were calculated respectively, with a minimum value of 20 and a maximum value of 80, reflecting the degree of state or trait anxiety. The test results of STAI Chinese translation in China show that its reliability and validity are satisfactory and suitable for China. SPSS 11 for Windows software is used for data input and analysis. This paper makes an empirical study on the correlation between general state anxiety, trait anxiety and foreign language anxiety. Results There were few high-frequency keywords in the relevant research, and the frequency was higher than 10%. The descending order was “sand table game”, “special education”, “game”, “autism”, “children”, “sports game”, “game teaching”, “game therapy”, “autistic children”, “initial sand table” and “psychotherapy”, showing the hot changes of the relevant research; The density of the whole network is 0.132, which is small and the information flow is poor; Through the analysis of aggregation degree and network average path length, the network aggregation degree is 0.369 and the average path length is 2.313, indicating that there is a small world effect in high-frequency keywords; Sand table games, special education, autism, children and games have great influence in the network. They are located in the center of the network. The average centrality of the whole keyword co-occurrence network knowledge map is 4.5, and the overall centrality of the network is very low; Compared with other keywords, “sand table game”, “special education” and “children” are the core of the network, and have a higher degree of control over other keywords; Sand table games, special education, autism and children have a high degree of independence and are not controlled by other keywords; Through community-based analysis, six modules are found from 0 to 5 modules, of which 0 groups of communities are research hotspots, including sand table games, children, initial sand table, game technology, case studies, psychotherapy, attention deficit hyperactivity disorder, special education schools, psychological rehabilitation, behavioral problems, assessment, college students, mental retardation, Connors parents questionnaire and symptom questionnaire are the connecting parts of personality assessment. Conclusions Psychological game technology is a relatively small group phenomenon in the research field of special education in China. Narrow research fields, few research hotspots, relatively loose research contents, insufficient research depth, loose research contents and insufficient research depth often lead to the generalization of relevant research, and the information exchange and cooperative research in relevant research fields need to be strengthened. In short, we should fully consider the important influence of psychological games on emotion, actively pay attention to the changes of their psychological emotion and behavior and their impact on positive and active behavior, actively organize rich activities flexibly according to the psychological characteristics of this part of the group, strive to build a relaxed and harmonious living atmosphere, create friendly and mutual assistance relations, encourage and guide this part of the group, and adjust their psychology to the best state, Promote the healthy development of their good cognition and life. Acknowledgments This study was supported by the Foundation of 2021 General Project of Humanities and Social Sciences Research of the Ministry of Education: Research on Professional Quality Improvement Strategies for Special Education Teachers in County Areas of the Western Region in the New Development Stage (no. 21YJA880046 to Ma Xiao-lan).

Realizing high-efficiency solar-driven CO

Real-time ultrasound imaging has been used for the evaluation of pulmonary abnormalities and other complications during the outbreak of COVID-19. However, conventional ultrasound examination requires operators to conduct scanning either in the examination room or patient ward, which may increase the potential infective risk. Tele-operated ultrasound robotics can provide a unique technique for doctors to remotely scan patients. During the COVID-19 pandemic, we attempted to apply a 5G network-based scanning robot to conduct remote ultrasound examination on COVID-19 patients and to explore the feasibility of this technique for teleultrasound diagnosis and consultation during critical infectious situations.

Two-dimensional graphitic carbon nitride (g-C3N4) has been widely explored as a promising photocatalyst for solar CO2 conversion. However, rapid charge recombination and low visible-light utilization are severely detrimental to photocatalytic CO2 conversion. Zero-dimensional/two-dimensional (0D/2D) heterostructures are considered the promising materials with size tunability and enhanced charge separation efficiency for photocatalysis. Herein, a 0D/2D heterostructure of oxygen vacancy-rich TiO2 quantum dots confined in g-C3N4 nanosheets (TiO2-x/g-C3N4) was prepared by in-situ pyrolysis of NH2-MIL-125 (Ti) and melamine. Charge dynamics analysis by time-resolved photoluminescence (tr-PL) and femtosecond and nanosecond pump-probed transient absorption (TA) spectra revealed that charges transfer occured from 2D-g-C3N4 to 0D-TiO2 at an ultrafast subpicosecond time scale (