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1.
J Colloid Interface Sci ; 605: 897-905, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34371433

RESUMO

The lack of the green, economical and high-efficient catalysts restrict the development of electrochemical nitrogen reduction reaction (NRR). By means of density functional theory (DFT) calculations, we have systematically investigated the NRR catalytic performance of single atoms decorated v-Mo2CT2 (T = O, F, OH, Cl, and Li) MXene (TM@v-Mo2CT2). Our calculation results reveal the introduction of single atom can significantly improve the NRR activity and selectivity on v-Mo2CO2, and Ir@v-Mo2CO2 system possesses the lowest limiting potential of only -0.33 V among all studied systems. The termination effects of TM@v-Mo2CT2 are further discussed and a descriptor of the adsorption energy of *NNH species (ΔE(*NNH)) is proposed to establish the relationship with NRR limiting potential (UL(NRR)), in which a moderate (ΔE(*NNH)) is required for high NRR activity. Moreover, a good linear relationship between the ΔE(*NNH) and the excess electrons on Ir atom shows that different ΔE(*NNH) originates from the difference of valence state of Ir atom, which is due to the change of coordination environment. Importantly, the synergistic effects of Ir atom and the surface O-terminations during the first hydrogenation step lead to a promoted NRR performance. Our study might provide new possibilities for rational design of cost-effective MXene-based NRR electrocatalysts.

2.
J Environ Sci (China) ; 109: 45-56, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34607673

RESUMO

Stringent quarantine measures during the Coronavirus Disease 2019 (COVID-19) lockdown period (January 23, 2020 to March 15, 2020) have resulted in a distinct decrease in anthropogenic source emissions in North China Plain compared to the paralleled period of 2019. Particularly, 22.7% decrease in NO2 and 3.0% increase of O3 was observed in Tianjin, nonlinear relationship between O3 generation and NO2 implied that synergetic control of NOx and VOCs is needed. Deteriorating meteorological condition during the COVID-19 lockdown obscured the actual PM2.5 reduction. Fireworks transport in 2020 Spring Festival (SF) triggered regional haze pollution. PM2.5 during the COVID-19 lockdown only reduced by 5.6% in Tianjin. Here we used the dispersion coefficient to normalize the measured PM2.5 (DN-PM2.5), aiming to eliminate the adverse meteorological impact and roughly estimate the actual PM2.5 reduction, which reduced by 17.7% during the COVID-19 lockdown. In terms of PM2.5 chemical composition, significant NO3- increase was observed during the COVID-19 lockdown. However, as a tracer of atmospheric oxidation capacity, odd oxygen (Ox = NO2 + O3) was observed to reduce during the COVID-19 lockdown, whereas relative humidity (RH), specific humidity and aerosol liquid water content (ALWC) were observed with noticeable enhancement. Nitrogen oxidation rate (NOR) was observed to increase at higher specific humidity and ALWC, especially in the haze episode occurred during 2020SF, high air humidity and obvious nitrate generation was observed. Anomalously enhanced air humidity may response for the nitrate increase during the COVID-19 lockdown period.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , COVID-19 , Poluentes Atmosféricos/análise , Poluição do Ar/análise , China , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Humanos , Material Particulado/análise , SARS-CoV-2
3.
JAMA Surg ; 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34613330

RESUMO

Importance: Preventing anastomotic leakage (AL) is crucial for colorectal surgery. Some studies have suggested a positive role of transanal drainage tubes (TDTs) in AL prevention after low anterior resection, but this finding is controversial. Objective: To assess the effect of TDTs in AL prevention after laparoscopic low anterior resection for rectal cancer. Design, Setting, and Participants: This multicenter randomized clinical trial with parallel groups (TDT vs non-TDT) was performed from February 26, 2016, to September 30, 2020. Participants included patients from 7 different hospitals in China who were undergoing laparoscopic low anterior resection with the double-stapling technique for mid-low rectal cancer; 576 patients were initially enrolled in this study, and 16 were later excluded. Ultimately, 560 patients were randomly divided between the TDT and non-TDT groups. Interventions: A silicone tube was inserted through the anus, and the tip of the tube was placed approximately 5 cm above the anastomosis under laparoscopy at the conclusion of surgery. The tube was fixed with a skin suture and connected to a drainage bag. The TDT was scheduled for removal 3 to 7 days after surgery. Main Outcomes and Measures: The primary end point was the postoperative AL rate within 30 days. Results: In total, 576 patients were initially enrolled in this study; 16 of these patients were excluded. Ultimately, 560 patients were randomly divided between the TDT group (n = 280; median age, 61.5 years [IQR, 54.0-68.8 years]; 177 men [63.2%]) and the non-TDT group (n = 280; median age, 62.0 years [IQR, 52.0-69.0 years]; 169 men [60.4%]). Intention-to-treat analysis showed no significant difference between the TDT and non-TDT groups in AL rates (18 [6.4%] vs 19 [6.8%]; relative risk, 0.947; 95% CI, 0.508-1.766; P = .87) or AL grades (grade B, 14 [5.0%] and grade C, 4 [1.4%] vs grade B, 11 [3.9%] and grade C, 8 [2.9%]; P = .43). In the stratified analysis based on diverting stomas, there was no significant difference in the AL rate between the groups, regardless of whether a diverting stoma was present (without stoma, 12 [5.8%] vs 15 [7.9%], P = .41; and with stoma, 6 [8.3%] vs 4 [4.5%], P = .50). Anal pain was the most common complaint from patients in the TDT group (130 of 280, 46.4%). Accidental early TDT removal occurred in 20 patients (7.1%), and no bleeding or iatrogenic colonic perforations were detected. Conclusions and Relevance: The results from this randomized clinical trial indicated that TDTs may not confer any benefit for AL prevention in patients who undergo laparoscopic low anterior resection for mid-low rectal cancer without preoperative radiotherapy. Trial Registration: ClinicalTrials.gov Identifier: NCT02686567.

4.
Artigo em Inglês | MEDLINE | ID: mdl-34617215

RESUMO

Recent studies have suggested that exposure to ambient airborne pollutants is associated with inflammatory skin diseases, but the epidemiological evidence regarding the association between air pollution and acne vulgaris is limited. To address that, a hospital-based time-series analysis was conducted in Xi'an, a metropolitan in northwest China. A total of 71,625 outpatient visits for acne from 2010 to 2013 were identified. The mean daily concentrations of PM10, SO2, and NO2 were 142.6 µg/m3, 44.7 µg/m3, and 48.5 µg/m3, and all were higher than WHO air quality guidelines. A generalized additive model was used to analyze the relationship between short-term ambient air pollution exposure and outpatient visits for acne. The gender- and age-specific analyses were conducted as well. The results showed that the increase of SO2 and NO2 concentrations corresponded to a significant rise in the number of outpatient visits for acne at lag 0 in both single-lag and cumulative exposure models. Both SO2 and NO2 were positively associated with acne outpatient visits for both males and females. In age-specific analyses, the effect estimate of PM10 was only significant for adults over 30 years old; SO2 was significantly associated with acne visits in children and adolescents (<21 years) and young adults (21-30 years); and NO2 was significantly associated with acne visits in all age subgroups. In conclusion, short-term exposure to ambient air pollutants (PM10, SO2, or NO2) with the average levels above WHO limits was associated with increased risk of outpatient visits for both teenage acne and adult acne. Moreover, the effects of air pollutants may vary with age.

5.
Plant Physiol ; 2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34618076

RESUMO

Replication protein A (RPA), a single-stranded DNA-binding protein, plays essential role in homologous recombination. However, because deletion of RPA causes embryonic lethality in mammals, the exact function of RPA in meiosis remains unclear. In this study, we generated an rpa1a mutant using CRISPR/Cas9 technology and explored its function in rice (Oryza sativa) meiosis. In rpa1a, 12 bivalents were formed at metaphase I, just like in wild-type, but chromosome fragmentations were consistently observed at anaphase I. Fluorescence in situ hybridization assays indicated that these fragmentations were due to the failure of the recombination intermediates to resolve. Importantly, the mutant had a highly elevated chiasma number, and loss of RPA1a could completely restore the 12 bivalent formations in the zmm (for ZIP1-4, MSH4/5, and MER3) mutant background. Protein-protein interaction assays showed that RPA1a formed a complex with the methyl methansulfonate and UV sensitive 81 (and the Fanconi anemia complementation group M-Bloom syndrome protein homologs (RECQ4A)-Topoisomerase3α-RecQ-mediated genome instability 1 complex to regulate chiasma formation and processing of the recombination intermediates. Thus, our data establish a pivotal role for RPA1a in promoting the accurate resolution of recombination intermediates and in limiting redundant chiasma formation during rice meiosis.

6.
Nanoscale ; 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34668505

RESUMO

Numerous recently developed therapies have highlighted the advantages of using proteins as therapeutics. However, in many protein delivery systems, the complicated carrier designs, low loading content, and off-targeting effects have limited their clinical applications. Here we report a photoresponsive protein-binding moiety and use it to prepare a simple nanoscale protein delivery system with high delivery efficiency and photoenhanced cellular uptake of proteins. The carrier was prepared by modifying a photocleavable molecule, DEACM, onto the surface of a cationic dendrimer, poly(amidoamine). DEACM simultaneously contributed to protein binding, self-assembly, and photocontrollability of the system. The multi-functional DEACM enabled the simplicity of the protein delivery system, which does not require complex organic synthesis or protein modification. The high delivery efficiency, high serum tolerance, and photoenhanced cellular uptake have been proved with functional proteins, presenting the potential for delivering protein therapeutics.

7.
BMC Infect Dis ; 21(1): 1012, 2021 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-34579666

RESUMO

BACKGROUND: The receptor of severe respiratory syndrome coronavirus 2 (SARS-CoV-2), angiotensin-converting enzyme 2, is more abundant in kidney than in lung tissue, suggesting that kidney might be another important target organ for SARS-CoV-2. However, our understanding of kidney injury caused by Coronavirus Disease 2019 (COVID-19) is limited. This study aimed to explore the association between kidney injury and disease progression in patients with COVID-19. METHODS: A retrospective cohort study was designed by including 2630 patients with confirmed COVID-19 from Huoshenshan Hospital (Wuhan, China) from 1 February to 13 April 2020. Kidney function indexes and other clinical information were extracted from the electronic medical record system. Associations between kidney function indexes and disease progression were analyzed using Cox proportional-hazards regression and generalized linear mixed model. RESULTS: We found that estimated glomerular filtration rate (eGFR) and creatinine clearance (Ccr) decreased in 22.0% and 24.0% of patients with COVID-19, respectively. Proteinuria was detected in 15.0% patients and hematuria was detected in 8.1% of patients. Hematuria (HR 2.38, 95% CI 1.50-3.78), proteinuria (HR 2.16, 95% CI 1.33-3.51), elevated baseline serum creatinine (HR 2.84, 95% CI 1.92-4.21) and blood urea nitrogen (HR 3.54, 95% CI 2.36-5.31), and decrease baseline eGFR (HR 1.58, 95% CI 1.07-2.34) were found to be independent risk factors for disease progression after adjusted confounders. Generalized linear mixed model analysis showed that the dynamic trajectories of uric acid was significantly related to disease progression. CONCLUSION: There was a high proportion of early kidney function injury in COVID-19 patients on admission. Early kidney injury could help clinicians to identify patients with poor prognosis at an early stage.


Assuntos
Injúria Renal Aguda , COVID-19 , Estudos de Coortes , Progressão da Doença , Humanos , Rim , Estudos Retrospectivos , Fatores de Risco , SARS-CoV-2
8.
J Colloid Interface Sci ; 607(Pt 2): 1005-1013, 2021 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-34583028

RESUMO

The development of highly-efficient electrocatalysts with bifunctional catalytic activity for oxygen reduction reaction (ORR) and oxygen evolution reaction. (OER) still remains a great challenge for the large-scale application of renewable energy conversion and storage technologies. Herein, by means of comprehensive density functional theory (DFT) computations, we systematically explored the potential of pyrrolic-N doped graphene (pyrrolic-N4-G) supported various transition metal atoms (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Pd, W, Os, Ir, and Pt) as electrocatalysts for the ORR and OER. Our results revealed that these TM/pyrrolic-N4-G candidates exhibit high electrochemical stability due to their positive dissolution potentials. Especially, the Ir/pyrrolic-N4-G can perform as a promising bifunctional electrocatalyst for both ORR and OER with the low overpotentials (ηORR = 0.34 V and ηOER = 0.32 V). Interestingly, multiple-level descriptors, including energy descriptor (ΔGOH* - ΔGO*), (ΔGOH*), structure descriptor (φ), and d-band center (ε) can well rationalize the origin of the high catalytic activity of Ir/pyrrolic-N4-G for the ORR/OER. Our findings not only further enrich the SACs, but also open a new avenue to develop novel 2D materials-based SACs for highly efficient oxygen electrocatalysts.

9.
Diabetes Res Clin Pract ; 180: 109041, 2021 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-34500004

RESUMO

AIMS: We aimed to investigate the role of Fasting Plasma Glucose (FPG) and glucose fluctuation in the prognosis of COVID-19 patients stratified by pre-existing diabetes. METHODS: The associations of FPG and glucose fluctuation indexes with prognosis of COVID-19 in 2,642 patients were investigated by multivariate Cox regression analysis. The primary outcome was in-hospital mortality; the secondary outcome was disease progression. The longitudinal changes of FPG over time were analyzed by the latent growth curve model in COVID-19 patients stratified by diabetes and severity of COVID-19. RESULTS: We found FPG as an independent prognostic factor of overall survival after adjustment for age, sex, diabetes and severity of COVID-19 at admission (HR: 1.15, 95% CI: 1.06-1.25, P = 1.02 × 10-3). Multivariate logistic regression analysis indicated that the standard deviation of blood glucose (SDBG) and largest amplitude of glycemic excursions (LAGE) were also independent risk factors of COVID-19 progression (P = 0.03 and 0.04, respectively). The growth trajectory of FPG over the first 3 days of hospitalization was steeper in patients with critical COVID-19 in comparison to moderate patients. CONCLUSIONS: Hyperglycemia and glucose fluctuation were adverse prognostic factors of COVID-19 regardless of pre-existing diabetes. This stresses the importance of glycemic control in addition to other therapeutic management.

10.
ACS Appl Mater Interfaces ; 13(38): 45269-45278, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34520159

RESUMO

Rationally constructing single-atom enzymes (SAEs) with superior activity, robust stability, and good biocompatibility is crucial for tumor therapy but still remains a substantial challenge. In this work, we adopt biocompatible carbon dots as the carrier material to load Ru single atoms, achieving Ru SAEs with superior multiple enzyme-like activity and stability. Ru SAEs behave as oxidase, peroxidase, and glutathione oxidase mimics to synchronously catalyze the generation of reactive oxygen species (ROS) and the depletion of glutathione, thus amplifying the ROS damage and finally causing the death of cancer cells. Notably, Ru SAEs exhibit excellent peroxidase-like activity with a specific activity of 7.5 U/mg, which surpasses most of the reported SAEs and is 20 times higher than that of Ru/C. Theoretical results reveal that the electrons of the Ru 4d orbital in Ru SAEs are transferred to O atoms in H2O2 and then efficiently activate H2O2 to produce •OH. Our work may provide some inspiration for the design of SAEs for cancer therapy.

11.
Bioengineered ; 12(1): 5323-5333, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34499008

RESUMO

N6-methyladenosine (m6A) methylation participates in the progression of bladder cancer (BCa). Nevertheless, the regulatory mechanism of alpha-ketoglutarate-dependent dioxygenase FTO influencing the BCa progression has still remained elusive. In this study, to investigate the tumor-suppressive effects of FTO via m6A RNA methylation on BCa patients, a total of 15 cancer tissues and adjacent normal tissues (ANTs) were collected from BCa patients who received tumor resection in our hospital from September 2015 to December 2019. We found that the FTO expression was significantly reduced in cancer tissues compared with that in ANTs, which indicated a lower malignant potential and a higher overall survival rate. It was revealed that overexpression of FTO in two human urinary BCa cell lines (HT-1197 and HT-1376) significantly decreased the cell proliferation and invasion abilities compared with the negative controls, whereas the cell apoptosis was markedly enhanced. In addition, we noted that the changes in m6A methylation level mainly appeared at 5' untranslated region (5' UTR) of MALAT1 and NOTCH1 transcripts, and at 3' UTR of CSNK2A2 and ITGA6 transcripts, responding to the overexpression of FTO. Mechanistically, we found that the splicing factor, proline- and glutamine-rich (SFPQ) could influence the FTO-mediated m6A RNA demethylation, eventually affecting the gene expression. This study provided a new insight into the relationship between the FTO expression and the m6A RNA methylation, assisting scholars to better understand the pathogenesis of BCa.

12.
Pathogens ; 10(8)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34451418

RESUMO

Carbapenem resistance has posed potential harmful risks to human and animals. The objectives of this study were to understand the prevalence of blaNDM-5 in pigs and investigate the molecular characteristics of NDM-5-producing Escherichia coli isolates in Guangdong province in China. Carbapenem-resistant E. coli isolates were isolated from pigs and obtained using MacConkey plates containing 0.5 mg/L meropenem. Conjugation assay and antimicrobial susceptibility testing were conducted for the isolates and their transconjugants. Whole-genome sequence (WGS) was used to analyze the plasmid genetic feature. A total of five blaNDM-5-carrying E. coli isolates were obtained in the present investigations. They belonged to five ST types. The blaNDM-5 genes were found to be in IncX3 and IncHI2 plasmid. The IncX3 plasmid was 46,161 bp in size and identical to other reports. IncHI2 plasmid was 246,593 bp in size and similar to other IncHI2-ST3 plasmids. It consisted of a typical IncHI2 plasmid backbone region and a multiresistance region (MRR). The blaNDM-5 was closely associated with the IS3000-ISAba125-blaNDM-5-bleMBL-trpF-tat-IS26 unit. We first reported the blaNDM-5-carrying IncHI2 in E. coli isolates recovered from pigs and revealed the molecular characterization. Continued surveillance for the dissemination of blaNDM-5 among food-producing animals is required.

13.
Ecotoxicol Environ Saf ; 224: 112633, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34411816

RESUMO

There are increasing concerns with regard to spontaneous abortion (SAB), the loss of pregnancy without external intervention before 20 weeks of gestation, among reproductive-aged women. To date, limited evidence is available concerning the association between SAB and air pollutants, especially in developing countries. Daily baseline outpatient data for SAB from January 1, 2014, to December 31, 2018 (1826 days) were obtained in Chongqing, a metropolis of southwest China. The over-dispersed Poisson generalized additive model with control of meteorological conditions and day of week was used to estimate the short-term effects of ambient air pollution on the daily number of SAB outpatients. A total of 42,334 SAB outpatient visits for SAB were recorded. No statistically significant association was observed between SAB and CO, PM2.5, PM10, O3, and SO2. The positive association only appeared for NO2: positive associations between SAB and NO2 were observed in both single-day models (lag 0, lag 1, lag 3, and lag 4) and cumulative exposure models (lag 01, lag 03, and lag 05) and the most significant effects were observed at lag 05 (3.289%; 95% CI: 1.568%, 5.011%). Moreover, the women with higher ages (30-39 and > 39) were more sensitive than those with lower ages (18-29), and the effect estimates were more evident in cool seasons. Collectively, our results suggested that short-term NO2 exposure was associated with higher risk of SAB, especially in elder women and cool seasons, which may contribute to further understand the role of air pollution on SAB and other adverse obstetric outcomes.

14.
Sci Rep ; 11(1): 16802, 2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34413327

RESUMO

To explore the effects of nitrogen deficiency in burley tobacco, two varieties were cultivated and subjected to conditions of sufficient and deficient nitrogen. The natural characteristics of varieties TN90 and TN86 during tobacco cultivation were similar for nitrogen metabolism. Both carbon and nitrogen metabolism were significantly affected by reducing amounts of applied nitrogen. Under nitrogen-deficient conditions, average leaf biomass, root weight, photosynthetic rate (Pn), pigment levels, total nitrogen, and nitrate content of TN86 and TN90 were significantly decreased by 52.88%, 69.19%, 22.65%, 46.80%, 37.42%, and 79.15%, respectively (p < 0.01). Nicotine and soluble reducing sugar contents were significantly decreased by 96.67% and 95.12%, respectively, in TN86 roots (p < 0.01), which was consistent with the reductions in root surf area, average diameter, and root volume. Nitrogen deficiency induced 6318 differentially expressed genes in both TN90 and TN86, which were highly expressed. In total, 428 upregulated genes were analysed and found to be mainly enriched in the MAPK signalling pathway, sesquiterpenoid and triterpenoid biosynthesis, and arginine and proline metabolism. Meanwhile, 213 downregulated genes were analysed and found to be mainly enriched in photosynthesis, nitrogen metabolism, and amino acid biosynthesis. Reduced pigment content and Pn may result in low carbohydrate formation and decreased leaf biomass in burley tobacco under nitrogen-deficient conditions.

15.
Adv Sci (Weinh) ; : e2101754, 2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34448360

RESUMO

Retinoblastoma is one of the most severe ocular diseases, of which current chemotherapy is limited to the repetitive intravitreal injections of chemotherapeutics. Systemic drug administration is a less invasive route; however, it is also less efficient for ocular drug delivery because of the existence of blood-retinal barrier and systemic side effects. Here, a photoresponsive drug release system is reported, which is self-assembled from photocleavable trigonal small molecules, to achieve light-triggered intraocular drug accumulation. After intravenous injection of drug-loaded nanocarriers, green light can trigger the disassembly of the nanocarriers in retinal blood vessels, which leads to intraocular drug release and accumulation to suppress retinoblastoma growth. This proof-of-concept study would advance the development of light-triggered drug release systems for the intravenous treatment of eye diseases.

16.
Plant J ; 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-34397127

RESUMO

In flowering plants, the transition from mitosis to meiosis is the precondition for gametogenesis, which is the most crucial event during sexual reproduction. Here, we report an intriguing mechanism whereby germ cells and surrounding somatic cells cooperatively involve in the meiotic switch during anther development in rice (Oryza sativa). In double mutants with loss function of both leptotene chromosome establishment- and somatic cell layer differentiation-associated genes, chromosome morphology in the reproductive cells remains the same as that in somatic cells, and sporogenous cells fail to differentiate into pollen mother cells. OsSPOROCYTELESS and MICROSPORELESS1, two pivotal genes involved in meiosis entry, are prominently downregulated in anthers of plants with mutations in both MULTIPLE SPOROCYTE1 and LEPTOTENE 1. In addition, the transcription of redox-related genes is also affected. Therefore, germ cells and the surrounding somatic cells collaboratively participate in meiosis initiation in rice.

17.
Int J Mol Sci ; 22(16)2021 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-34445247

RESUMO

The utilization of heterosis is an important way to improve wheat yield, and the production of wheat hybrid seeds mainly relies on male-sterile lines. Male sterility in line 15 Fan 03 derived from a cross of 72,180 and Xiaoyan 6 is controlled by a single recessive gene. The gene was mapped to the distal region of chromosome 4BS in a genetic interval of 1.4 cM and physical distance of 6.57 Mb between SSR markers Ms4BS42 and Ms4BS199 using an F2 population with 1205 individuals. Sterile individuals had a deletion of 4.57 Mb in the region presumed to carry the Ms1 locus. The allele for sterility was therefore named ms1s. Three CAPS markers were developed and verified from the region upstream of the deleted fragment and can be used for ms1s marker-assisted selection in wheat hybrid breeding. This work will enrich the utilization of male sterility genetic resources.


Assuntos
Mapeamento Cromossômico , Genes de Plantas , Genes Recessivos , Loci Gênicos , Infertilidade das Plantas/genética , Triticum/genética , Melhoramento Vegetal
18.
Phys Chem Chem Phys ; 2021 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-34373884

RESUMO

The electroreduction of dinitrogen (N2) is an attractive method for ambient ammonia (NH3) synthesis. In this work, double boron atom-anchored two-dimensional (2D) graphdiyne (GDY-2B) electrocatalysts have been designed and examined for the N2 reduction reaction (NRR) by density functional theory computations. Our calculations revealed that double boron atoms can be strongly embedded in a graphdiyne monolayer. In particular, configuration GDY-2B(S2S2') with two boron atoms substituting two equivalent sp-carbon atoms of diacetylene linkages exhibits excellent catalytic performance for reducing N2, with an extremely low overpotential of 0.12 V. The "pull-pull" mechanism imposed by doped double boron atoms is responsible for the magnificent effect of N2 activation. Besides, the competitive reaction of the hydrogen evolution reaction (HER) is suppressed owing to a large ΔGH* value of -1.25 eV. Based on these results, our study provides useful guidelines for designing effective double atomic catalysts (DACs) based on nonmetal 2D nanosheets for effective electrochemical reduction reactions.

19.
Small ; 17(38): e2102295, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34365730

RESUMO

As one of the most promising drug-delivery carriers due to its small size, easy surface modifiability, and hydrophobic interior, cationic poly(amidoamine) (PAMAM) per se, demonstrated by previous reports and the authors' present study, indicate potential anticancer capability, however, which are restricted by autophagy elicitation. Besides, its side-toxicity profile, having also been extensively documented, limits its translation into the clinic. Herein, the authors design a photoresponsive PAMAM-assembled nanoparticle loaded with the autophagy inhibitor (chloroquine, CQ), which exhibits light responsiveness for precisely controlling drug release and superior dark biosafety. Upon light irradiation, the nanoparticle can dissociate into charged small PAMAM for a significant antitumor effect. Meanwhile, the released CQ can inhibit pro-survival autophagy induced by PAMAM to achieve an excellent synergistic anticancer efficacy in vitro and in vivo. The authors' study provided a vision of utilizing PAMAM as self-carried anticancer therapeutics in combination with an autophagy inhibitor and proposing a cancer therapy with high antitumor efficacy and low side effects to normal tissues.

20.
Nat Commun ; 12(1): 4080, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34215749

RESUMO

Urea is an important raw material in the chemical industry and is widely used as a nitrogen source in chemical fertilizers. The current industrial urea synthesis not only requires harsh reaction conditions, but also consumes most of the NH3 obtained through artificial synthesis. The conversion of N2 and CO2 into urea through electrochemical reactions under ambient conditions represents a novel green urea synthesis method. However, the large-scale promotion of this method is limited by the lack of suitable electrocatalysts. Here, by means of density functional theory computations, we systematically study the catalytic activity of three experimentally available two-dimensional metal borides (MBenes), Mo2B2, Ti2B2, and Cr2B2 toward simultaneous electrocatalytic coupling of N2 and CO2 to produce urea under ambient conditions. According to our results, these three MBenes not only have superior intrinsic basal activity for urea formation, with limiting potentials ranging from -0.49 to -0.65 eV, but also can significantly suppress the competitive reaction of N2 reduction to NH3. In particular, 2D Mo2B2 and Cr2B2 possess superior capacity to suppress surface oxidation and self-corrosion under electrochemical reaction conditions, rendering them relatively promising electrocatalysts for urea production. Our work paves the way for the electrochemical synthesis of urea.

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