A strategy to covalently connect crystalline covalent organic frameworks (COFs) with semiconductors to create stable organic–inorganic Z‐scheme heterojunctions for artificial photosynthesis is ...presented. A series of COF–semiconductor Z‐scheme photocatalysts combining water‐oxidation semiconductors (TiO2, Bi2WO6, and α‐Fe2O3) with CO2 reduction COFs (COF‐316/318) was synthesized and exhibited high photocatalytic CO2‐to‐CO conversion efficiencies (up to 69.67 μmol g−1 h−1), with H2O as the electron donor in the gas–solid CO2 reduction, without additional photosensitizers and sacrificial agents. This is the first report of covalently bonded COF/inorganic‐semiconductor systems utilizing the Z‐scheme applied for artificial photosynthesis. Experiments and calculations confirmed efficient semiconductor‐to‐COF electron transfer by covalent coupling, resulting in electron accumulation in the cyano/pyridine moieties of the COF for CO2 reduction and holes in the semiconductor for H2O oxidation, thus mimicking natural photosynthesis.
Here comes the sun: A strategy to covalently connect covalent organic frameworks with semiconductors to create organic–inorganic Z‐scheme heterojunctions was developed and applied for the CO2 photoreduction with H2O. This work delivers new insights for the future design of Z‐scheme organic–inorganic heterojunctions for artificial photosynthesis.
A Z-scheme heterostructure is a kind of highly efficient photocatalyst that can not only reduce the forbidden band width of the semiconductor but also promote the redox reaction in the photocatalytic ...system. Herein, calculations on the work function and charge density difference by density functional theory (DFT) methods prove that g-C3N4/SnS2 and B-doped g-C3N4/SnS2 are Z-scheme heterostructures. Compared to g-C3N4, the Z-scheme heterostructures show narrower band gaps, and red-shifted and stronger light absorption with remarkably improved photocatalytic activity. The reaction free energy for each step of the CO2 reduction process was calculated to further evaluate the photocatalytic activity of g-C3N4/SnS2 and B-doped g-C3N4/SnS2. The products of CO2RR catalyzed by g-C3N4/SnS2 are CH3OH and CH4, which are in good agreement with experiments, and the rate-determining step is CO2 → COOH* with a ΔG of 1.10 eV. For B-doped g-C3N4/SnS2, the optimal path is CO2 → COOH* → CO* → HCO* → CHOH* → CH* → CH2* → CH3* → CH4, and the rate-determining step is CH2* → CH3* with a ΔG of 0.40 eV. The results show that the CO2 reduction activity of B-doped g-C3N4/SnS2 is better than that of g-C3N4/SnS2. Therefore, the Z-scheme B-doped g-C3N4/SnS2 heterostructure is predicted to be a promising catalyst for CO2 reduction to CH4.
Due to its growing application in various industries as a marketing tool, the travel industry is increasingly perceiving the potential of virtual reality (VR) in the tourism arena. Although VR has ...been widely discussed in practice management research, there is, however, little knowledge on how VR technology can be applied in themed tourism environments. Hence, in this study, we use the Zaltman Metaphor Elicitation Technique (ZMET) to empirically study how visitors express their inner values and meanings through VR-themed tourism. We invited 26 respondents to participate in a VR-themed tourism experience, and we organized our results based on three key themes. First, characteristics of VR-themed tourism such as 'freedom of virtual reality', 'escapism of virtual reality' and 'anxiety of virtual reality' were summarized. Second, an objective consensus map was created using the 'conservative', 'average' and 'optimistic' calculation procedures. Third, we determined the relevance of the integrated linking constructs. We found that 'imagination' and 'fantasy dream' have the highest relevance value, followed by 'illusion' and 'illusionary situation'. These themes could thus provide new insights into the possible intertwined integration and complexity of 'virtual' and 'physical' issues that may arise when tourists experience VR-themed tourism.
The COVID-19 pandemic across Chinese mainland was gradually stabilized at a low level with sporadic outbreaks, before the emergence of Omicron variant. Apart from non-pharmacological interventions ...(NPIs), COVID-19 vaccine has also been implemented to prevent and control the pandemic since early 2021. Although many aspects have been focused, the change of the spatiotemporal distribution of COVID-19 epidemic across Chinese mainland responding to the change of prevention and control measures were less concerned. Here, we collected the confirmed case data (including domestic cases and overseas imported cases) across Chinese mainland during both 2020/04-2020/08 and 2021/04-2021/08, and then conducted a preliminary data comparison on the spatiotemporal distribution of confirmed cases during the identical period between the two years. Distribution patterns were evaluated both qualitatively by classification method and quantitatively through employing coefficient of variation. Results revealed significant differences in the homogeneity of spatiotemporal distributions of imported or domestic cases between the two years, indicating that the important effect of the adjustment of prevention and control measures on the epidemic evolution. The findings here enriched our practical experience of COVID-19 prevention and control. And, the collected data here might be helpful for improving or verifying spatiotemporally dynamic models of infectious diseases.
Natural selection serves as an important agent to drive and maintain interspecific divergence. Populus rotundifolia Griff. is an alpine aspen species that mainly occurs in the Qinghai–Tibet Plateau ...(QTP) and adjacent highlands, whereas its sister species, P. davidiana Dode, is distributed across southwest and central to northeast China in much lower altitude regions. In this study, we collected genome resequencing data of 53 P. rotundifolia and 42 P. davidiana individuals across their natural distribution regions. Our population genomic data suggest that the two species are well delimitated in the allopatric regions, but with hybrid zones in their adjacent region in the eastern QTP. Coalescent simulations suggest that P. rotundifolia diverged from P. davidiana in the middle Pleistocene with following continuous gene flow since divergence. In addition, we found numerous highly diverged genes with outlier signatures that are likely associated with high‐altitude adaptation of these alpine aspens. Our finding indicate that Quaternary climatic changes and natural selection have greatly contributed to the origin and distinction maintenance of P. rotundifolia in the QTP.
In this study, we collected genome‐resequencing data of 53 Populus rotundifolia and 42 P. davidiana individuals across their natural distribution regions. Our population genomic data suggest that the two species are well delimitated in the allopatric regions, but with hybrid zones in their adjacent region in the eastern Qinghai–Tibet Plateau (QTP). Our finding indicate that Quaternary climatic changes and natural selection have greatly contributed to the origin and distinction maintenance of P. rotundifolia in the QTP.
Aiming at constructing photoresponsive spin crossover (SCO) behavior, herein we designed a new ligand Abtz (Abtz = (
)-
-(4-((
)-phenyldiazenyl)phenyl)-1-(thiazol-4-yl)methanimine) which was ...decorated by a photochromic azobenzene group. Based on this photochromic ligand, a mononuclear Fe(II) SCO molecule Fe(Abtz)
(BF
)
·(EAC)
(
, EAC = ethyl acetate) was successfully synthesized and showed a complete one-step SCO behavior. Under continuous UV light and blue-light exposure, the
photoisomerization of both ligand Abtz and compound
in the liquid phase was confirmed through UV-Vis spectra. Moreover, the
H-NMR spectra of Abtz reveal a
conversion ratio of 37%. Although the UV-Vis spectra reveal the photochromic behavior for
in the solution phase, the SCO behavior in the liquid state is absent according to the variable-temperature Evans method, suggesting the possible decomposition. Moreover, in the solid state, the
photoisomerization of both Abtz and
was not observed, due to the steric hindrance.
Understanding the interaction between large herbivores and pasture production, especially with respect to the grazing optimization hypothesis, is critical for pasture management and generating ...theoretical and testable predictions. However, the optimization hypothesis remains contradictory in alpine meadows on the Qinghai-Tibet Plateau (QTP). In this study, we tested the grazing optimization hypothesis using four yak-grazing intensities (no grazing, light grazing, moderate grazing and heavy grazing) in alpine meadow habitats from 2015 to 2017. The results indicated that species diversity did not differ significantly among grazing regimes during the experimental period. However, the aboveground net primary production (ANPP) under moderate grazing consistently significantly exceeded that in control enclosures over 3 years, confirming the grazing optimization hypothesis. Levels of overcompensation varied among grazing intensities and years, and grazing-induced plant compensation may only occur in the short term. The enhanced regrowth of
and
induced by yak grazing might contribute to the overall level of overcompensation by plant community. Our results strongly support the grazing optimization hypothesis in the context of alpine meadows grazed by yaks, emphasizing the complex interactions between ANPP, herbivores and other ecological factors in alpine meadows on the QTP. These findings provide new insights for the development of an ecological conservation strategy that will help restore this fragile ecosystem and balance the seemingly incompatible requirements of animal husbandry.
Currently, one sixth of triple-negative breast cancer (TNBC) patients who receive docetaxel (T) and epirubicin (E) as neoadjuvant chemotherapy achieve a pathologic complete response (pCR). This study ...evaluates the impact of adding lobaplatin (L) to the TE regimen. Here, we show data from 125 patients (63 TE and 62 TEL patients). Four patients did not complete all the cycles. Two-sided P values show that the addition of L (38.7% vs. 12.7%, P = 0.001) significantly increases the rate of pCR in the breast and the axilla (TpCR) and the overall response rate (ORR; 93.5% vs. 73.0%, P = 0.003). The occurrence of grade 3-4 anemia and thrombocytopenia is higher in the TEL group (52.5% vs. 10.0% and 34.4% vs. 1.7% respectively). These results demonstrate that the addition of L to the TE regimen as neoadjuvant chemotherapy improves the TpCR and the ORR rates of TNBC but with increased side effects.
Major depressive disorder is a common and devastating psychiatric disease, and the prevalence and burden are substantially increasing worldwide. Multiple studies of depression patients have ...implicated glucose metabolic dysfunction in the pathophysiology of depression. However, the molecular mechanisms by which glucose and related metabolic pathways modulate depressive-like behaviors are largely uncharacterized. Uridine diphosphate N-acetylglucosamine (UDP-GlcNAc) is a glucose metabolite with pivotal functions as a donor molecule for O-GlcNAcylation. O-GlcNAc transferase (OGT), a key enzyme in protein O-GlcNAcylation, catalyzes protein posttranslational modification by O-GlcNAc and acts as a stress sensor. Here, we show that Ogt mRNA was increased in depression patients and that astroglial OGT expression was specifically upregulated in the medial prefrontal cortex (mPFC) of susceptible mice after chronic social-defeat stress. The selective deletion of astrocytic OGT resulted in antidepressant-like effects, and moreover, astrocytic OGT in the mPFC bidirectionally regulated vulnerability to social stress. Furthermore, OGT modulated glutamatergic synaptic transmission through O-GlcNAcylation of glutamate transporter-1 (GLT-1) in astrocytes. OGT astrocyte-specific knockout preserved the neuronal morphology atrophy and Ca2+ activity deficits caused by chronic stress and resulted in antidepressant effects. Our study reveals that astrocytic OGT in the mPFC regulates depressive-like behaviors through the O-GlcNAcylation of GLT-1 and could be a potential target for antidepressants.
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