Hybrid Zeolitic Imidazolate Frameworks for Promoting Electrocatalytic Oxygen Evolution via a Dual-Site Relay Mechanism.

Developing efficient oxygen evolution reaction (OER) electrocatalysts is important for enhancing the water splitting efficiency. However, with the current catalysts containing one kind of active sites, it is challenging to achieve low overpotentials because of the four-electron transfer process. Herein is reported HZIF-2-CoMo, a new metal-organic framework with well-defined Co-Mo dual sites that can promote the OER process through an unconventional Mo6+/Co2+ dual-site relay mechanism. Theoretical calculations suggested that the Mo and Co sites stabilize the HO* and HOO* intermediates, respectively, and that the unique Co-O-Mo configuration induces the formation of a Co-O*-Mo transition intermediate, remarkably reducing the reaction free energy. As a result, HZIF-2-CoMo shows an overpotential of 277 mV at 10 mA cm-2 and a low Tafel slope of 70 mV dec-1 in alkaline solution, making it one of the best OER electrocatalysts reported to date.

Transcriptome-Wide Analysis Reveals the Origin of Peloria in Chinese Cymbidium (Cymbidium sinense).

An orchid flower exhibits a zygomorphic corolla with a well-differentiated labellum. In Cymbidium sinense, many varieties with peloric or pseudopeloric flowers have been bred during centuries of domestication. However, little is known about the molecular basis controlling orchid floral zygomorphy and the origin of these varieties. Here, we studied the floral morphogenesis of C. sinense and transcriptome-wide enriched differentially expressed genes among different varieties. The floral zygomorphy of C. sinense is established in the early developmental process. Out of 27 MIKCC-MADS factors, we found two homeotic MADS genes whose expression was down-regulated in peloric varieties but up-regulated in pseudopeloric varieties. CsAP3-2 expressed in the inner floral organs co-operates with a labellum-specific factor CsAGL6-2, asymmetrically promoting the differentiation of inner tepals. Interestingly, we detected exon deletions on CsAP3-2 in peloric varieties, indicating that loss of B-function results in the origin of peloria. Additional petaloid structures developed when we ectopically expressed these genes in Arabidopsis, suggesting their roles in floral morphogenesis. These findings indicate that the interplay among MADS factors would be crucial for orchid floral zygomorphy, and mutations in these factors may have maintained during artificial selection.

NH4 Be2 BO3 F2 and γ-Be2 BO3 F: Overcoming the Layering Habit in KBe2 BO3 F2 for the Next-Generation Deep-Ultraviolet Nonlinear Optical Materials.

KBe2 BO3 F2 (KBBF) is still the only practically usable crystal that can generate deep-ultraviolet (DUV) coherent light by direct second harmonic generation (SHG). However, applications are hindered by layering, leading to difficulty in the growth of thick crystals and compromised mechanical integrity. Despite efforts, it is still a great challenge to discover new nonlinear optical (NLO) materials that overcome the layering while keeping the DUV SHG available. Now, two new DUV NLO beryllium borates have been successfully designed and synthesized, NH4 Be2 BO3 F2 (ABBF) and γ-Be2 BO3 F (γ-BBF), which not only overcome the layering but also can be used as next-generation DUV NLO materials with the shortest type I phase-matching second-harmonic wavelength down to 173.9 nm and 146 nm, respectively. Significantly, γ-BBF is superior to KBBF in all metrics and would be the most outstanding DUV NLO crystal.

Achievement of Bulky Homochirality in Zeolitic Imidazolate-Related Frameworks.

Before this work, adding chiral C centers into zeolitic imidazolate frameworks (ZIFs) has never been realized. Presented here are the first examples on achieving bulky homochirality in ZIF systems, and three homochiral zeolitic imidazolate-related frameworks with sodalite and dia topologies are successfully synthesized by employing enantiopure imidazolate derivatives. The results open a new blueprint on the synthetic design of homochiral ZIFs for future applications.

A cluster of two psittacosis cases among women farmers exposed to Chlamydia psittaci-infected domestic poultry in Zhejiang Province, China.

A cluster of Chlamydia psittaci (C. psittaci) cases was reported in Zhejiang Province, China, 2019. This study evaluates the extent of the outbreak and determines the source of infection. Real-time PCR and sequencing of the ompA gene of C. psittaci were performed to identify the cases, the domesticated poultry and close contacts. The index patient was a 76-year-old woman with chronic vertigo, and Case 2 was a 64-year-old female farmer with herpes zoster. Both women bought psittaci-infected chickens or ducks from the same mobile street vendor and raised them for 10 days and 23 days before fever onset. There were no direct contact between the two women. C. psittaci test was positive for the two patients, one sick chicken, three healthy ducks and the vendor's chicken cage. Phylogenetic analysis showed that all seven C. psittaci positive samples carried identical ompA genotype A of C. psittaci. Of all of the patients' 148 close contacts, none tested positive for C. psittaci, or developed acute respiratory symptoms. Both patients were discharged after a 4-week hospital stay. In conclusion, the source of this cluster was the poultry infected with C. psittaci, which occasionally cause infections in farmers, but inter-human transmission seems unlikely.

Analysis of dose-effect relationship between DVH parameters and clinical prognosis of definitive radio(chemo)therapy combined with intracavitary/interstitial brachytherapy in patients with locally advanced cervical cancer: A single-center retrospective study.

PURPOSE: The purpose of the study was to explore the dose-effect relationship between dose-volume histogram parameters and clinical prognosis of definitive radio(chemo)therapy followed by intracavitary/interstitial brachytherapy in locally advanced cervical cancer. METHODS AND MATERIALS: A retrospective analysis was performed on 110 patients with locally advanced cervical cancer who underwent external beam radiotherapy combined with intracavitary/interstitial brachytherapy with or without chemotherapy from July 2010 to September 2018. We reported D100, D98, and D90 for high-risk clinical target volume (HR-CTV) and intermediate-risk clinical target volume, D2cm³ for organs at risk. Multivariate Cox regression was used to screen independent factors. Dose-volume parameters screened by the Cox regression were incorporated into the probit model for investigating its relationship with survival. RESULTS: The median followup time was 72.33 months. Multivariate Cox regression analysis showed that HR-CTV D100, HR-CTV D98, and HR-CTV D90 were independent factors, affecting the 5-year overall survival (OS), cancer-specific survival (CSS), and local control (LC) rates. The probit model showed that HR-CTV D98 had predictive values for the 5-year OS, CSS, and LC, and HR-CTV D100 had predictive values for the 5-year OS, CSS, whereas HR-CTV D90 had a predictive value only for the 5-year OS. The HR-CTV D98 corresponding to OS ED90, CSS ED90, and LC ED90 was 86.8, 85.6, and 78.6 Gy, respectively. CONCLUSIONS: A significant dependence of OS, CSS, and LC on D98 for HR-CTV was found. When the long-term OS, CSS, and LC rate of the patient was >90%, HR-CTV D98 > 86.8 Gy EQD2, 85.6 Gy EQD2, and 78.6 Gy EQD2 were required.

Construction of unprecedented pillar-layered metal organic frameworks via a dual-ligand strategy for dye degradation.

A dual-ligand strategy is used to construct two pillar-layered metal organic frameworks (MOFs) with [Zn2(COO)3]+ subunits (SBUs) and [ZnxCo3-x(ethanol)2(COO)4]2+ SBUs, respectively. Remarkably, the Zn/Co mixed compound 2 exhibits excellent and adjustable photocatalytic activity to degrade crystal violet (CV) in water under visible light.

An AGAMOUS-like factor is associated with the origin of two domesticated varieties in Cymbidium sinense (Orchidaceae).

Cymbidium has been artificially domesticated for centuries in Asia, which produced numerous cultivated varieties. Flowers with stamenoid tepals or those with multiple tepals have been found in different species of Cymbidium; however, the molecular basis controlling the formation of these phenotypes is still largely unknown. Previous work demonstrated that AGAMOUS/AG lineage MADS genes function in floral meristem determinacy as well as in reproductive organs development in both dicots and monocots, indicating a possible relationship with the origin of two flower varieties in Cymbidium. Here, we characterized and analyzed two AG lineage paralogues, CsAG1 and CsAG2, from Cymbidium sinense, both of which were highly expressed in the gynostemium column of a standard C. sinense. Interestingly, we detected ectopic expression of CsAG1 rather than CsAG2 in all floral organs of a stamenoid-tepal variety and significant down-regulation of CsAG1 in a variety with multiple tepals. Over-expression of CsAG1 in wild type Arabidopsis resulted in petal-to-stamen homeotic conversion, suggesting a conserved C-function of CsAG1 in the development of Cymbidium flower. Altogether, our results supported a hypothesis that disruption of a single AG-like factor would be associated with the formation of two domesticated varieties in C. sinense.

Collaborative enhancement from Pb2+ and F- in Pb2(NO3)2(H2O)F2 generates the largest second harmonic generation effect among nitrates.

The first metal nitrate fluoride nonlinear optical material, Pb2(NO3)2(H2O)F2, was synthesized with the largest second harmonic generation (SHG) effect (12 × KH2PO4) among nitrates. Theoretical calculations revealed the synergistic effect of [NO3]-, lone pair electrons in Pb2+, and F- for the SHG effect. The F- also promoted the blue-shift of the ultraviolet cut-off edge.

Diverse tetrahedral tetrazolate frameworks with N-rich surface.

Three tetrahedral tetrazolate frameworks (TTFs) with SOD, and topologies (TTF-4, -5 and -6) are obtained by using the anion and solvent as structure-directing agents. The resulting SOD-type TTF-4 shows high chemical stability as well as high CO2 uptake capacity.