In this article, pure phase metastable wurtzite Cu 2 ZnSnS 4 (CZTS) nanocrystals (NCs) were synthesized by a facile one-pot method. When pure 1dodecanethiol (DDT) was used as the solvent, two coexisting CZTS phases (wurtzite and kesterite) were found. When an increased amount of oleylamine (OAm) was added to DDT, kesterite CZTS disappeared gradually, and the asobtained CZTS NCs became smaller and more uniform. When 0.5 mL of OAm was added, rice-like pure phase metastable wurtzite CZTS NCs were obtained. The factors, including amount of OAm, reaction temperature, reaction time, and concentration of precursors, which influence the morphology, size, and monodispersity of CZTS NCs, were studied in detail. The results showed OAm played an important role in the formation of the final pure phase metastable wurtzite NCs. Time-dependent experiments were performed to observe the growth of CZTS NCs. The final CZTS NCs evolved from spherical-like Cu 2 S NCs through rhombuslike intermediate shaped NCs to rice-like pure wurtzite CZTS NCs. On the basis of the detailed time-dependent shape and elemental composition evolutions, a possible asynchronous doping growth and formation mechanism was proposed. The optical and electrical properties of the pure wurtzite CZTS NCs were also investigated. The band gap of the rice-like CZTS is about 1.49 eV, which approaches the optimum value for solar photoelectric conversion. Meanwhile, the current−voltage characteristics and Hall effect measurement of the wurtzite CZTS NCs films indicated that rice-like CZTS NCs favored the electronic transmission and thus may induce the generation of photocurrent. Thus, the obtained wurtzite CZTS NCs are more suitable for using as absorber layer in low cost solar cells.

The continuous-variable version of quantum key distribution (QKD) offers the advantages (over discrete-variable systems) of higher secret key rates in metropolitan areas, as well as the use of standard telecom components that can operate at room temperature. An important step in the real-world adoption of continuous-variable QKD is the deployment of field tests over commercial fibers. Here we report two different field tests of a continuousvariable QKD system through commercial fiber networks in Xi'an and Guangzhou over distances of 30.02 km (12.48 dB) and 49.85 km (11.62 dB), respectively. We achieve secure key rates two orders-of-magnitude higher than previous field test demonstrations by employing an efficient calibration model with one-time evaluation. This accomplishment is also realized by developing a fully automatic control system which stabilizes system noise, and by applying a rate-adaptive reconciliation method which maintains high reconciliation efficiency with high success probability in fluctuated environments. Our results pave the way to deploy continuousvariable QKD in metropolitan settings.

In this paper, novel hierarchical Cu2ZnSnS4 (CZTS) particles were synthesized by a solvothermal method. The effects of synthetic conditions, such as reaction temperature, reaction time, solution concentration, and the amount of PVP, were investigated. The results showed that the size and morphology of the CZTS particles can be controlled by changing the reaction conditions and that PVP played an important role in the formation of the final hierarchical particles. Time-dependent results showed that the nucleation and growth of the CZTS particles were governed by a nucleation–dissolution–recrystallization growth mechanism. The optical and electrical properties of the CZTS particles were also investigated. Compared with spherelike CZTS particles and CZTS nanocrystals, the absorption of typical hierarchical CZTS particles decayed more slowly, indicating a higher absorption coefficient in the visible region. Meanwhile, the current–voltage characteristics of the CZTS films indicated that flowerlike particles favored the electronic transmission and thus may induce the generation of photocurrent. Thus, the obtained hierarchical CZTS particles are more suitable for using as an absorber layer in low-cost solar cells.

Rheumatoid arthritis (RA) is a worldwide inflammatory disease that seriously threatens human health and needs more effective treatment approaches. Near infrared (NIR) light can efficiently penetrate inflamed joints affected by RA, so phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT), may provide new opportunities. In this work, the unique Cu S nanoparticles (NPs) are prepared for RA treatment enlightened by the fact that copper (Cu)-based nanomaterials can simultaneously serve as PTT agents and photosensitizers (for PDT). Meanwhile, Cu can promote ostogenesis and chondrogenesis. The Cu S NPs combined with NIR (808 nm, 1 W cm ) irradiation not only achieve better bone preservation, including higher bone mineral density (BMD) and bone volume/total volume, but also inhibit inflamed synovial invasion, cartilage erosion, and expression of proinflammatory cytokines in vivo. Moreover, the Cu S NPs can effectively kill clinical pathogenic Staphylococcus aureus and Escherichia coli to prevent bacterial infection during intra-articular injection. Therefore, the combined PTT and PDT using the multifunctional Cu S NPs could be a novel RA treatment modality with full potential.

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Background The COVID-19 pandemic has posed significant threats to both the physical and psychological health of healthcare workers working in the front-line combating COVID-19. However, studies regarding the medium to long term impact of COVID-19 on mental health among healthcare workers are limited. Therefore, we conducted this cross-sectional survey to investigate the prevalence, factors and impact of post-traumatic stress disorder (PTSD) in healthcare workers exposed to COVID-19 8 months after the end of the outbreak in Wuhan, China. Methods A web-based questionnaire was delivered as a link via the communication application WeChat to those healthcare workers who worked at several COVID-19 units during the outbreak (from December 2019 to April 2020) in Wuhan, China. The questionnaire included questions on social-demographic data, the post-traumatic stress disorder checklist-5 (PCL-5), the family care index questionnaire (Adaptation, Partnership, Growth, Affection and Resolve, APGAR), and the quality-of-life scale (QOL). The prevalence, risk and protective factors, and impact of PTSD on healthcare workers were subsequently analyzed. Results Among the 659 participants, 90 healthcare workers were still suffering from PTSD 8 months after the end of the outbreak of COVID-19 in Wuhan, in which avoidance and negative impact were the most affected dimensions. Suffering from chronic disease, experiencing social isolation, and job dissatisfaction came up as independent risk factors for PTSD, while obtaining COVID-19 related information at an appropriate frequency, good family function, and working in well-prepared mobile cabin hospitals served as protective factors. The impact of PTSD on COVID-19 exposed healthcare workers was apparent by shortened sleeping time, feeling of loneliness, poorer quality of life and intention to resign. Conclusions Eight months after the end of the COVID-19 outbreak in Wuhan, the level of PTSD in healthcare workers exposed to COVID-19 was still high. Apart from the commonly recognized risk factors, comorbid chronic disease was identified as a new independent risk factor for developing PTSD. For countries where the pandemic is still ongoing or in case of future outbreaks of new communicable diseases, this study may contribute to preventing cases of PTSD in healthcare workers exposed to infectious diseases under such circumstances.

Recent research suggests that exposure to monetary cues strengthens an individual’s motivation to pursue monetary rewards by inducing the ‘market mode’ (i.e. thinking and behaving in accordance with market principles). Here, we examined the effect of market mode on social reward processes by means of event-related potentials (ERPs). Participants primed with monetary images or neutral images acted as advisors who selected one of two options for a putative advisee. Subsequently, all participants passively observed the advisee accepting or rejecting their advice and receiving a gain or loss outcome. After money priming, the feedback-related negativity (FRN) to the advisee’s gain/loss outcome was larger following incorrect as compared to correct advice irrespective of whether the advice had been accepted or rejected. A smaller P3 following incorrect advice showed only when the advice was rejected. After neutral priming, the FRN was larger for incorrect relative to correct advice only when the advice had been rejected. However, the P3 was larger for correct relative to incorrect advice irrespective of the advisee’s final choice. These findings suggest that the market mode facilitates early and automatic feedback processing but reduces later and controlled responding to outcomes that had been accepted.