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1.
Sci Rep ; 11(1): 16310, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34381115

RESUMO

The coronavirus disease (COVID-19) has already been declared a global pandemic. To our knowledge, there is very little information regarding the effects of COVID-19 on women seeking reproductive health services, specifically abortion. This study was aimed to assess the impact of the COVID-19 pandemic on reproductive and sexual health among women seeking abortion services. We conducted a series of preliminary analyses using data collected from ten maternal and child health hospitals of seven provinces in China before and during the COVID-19 lockdown. The present study showed that a significant decrease was observed in the frequency of sexual intercourse during the COVID-19 pandemic. Moreover, a significant increase in contraceptive use including condom, rhythm method and coitus interruptus whereas a decrease in choosing oral contraceptives were observed during the COVID-19 pandemic. In addition, the pandemic was associated with increased intention of seeking induced abortion due to social factors. Future research should look into the long-term impact of the COVID-19 pandemic on sexual and reproductive health.


Assuntos
Aborto Induzido , COVID-19/fisiopatologia , Reprodução , Saúde Sexual , Adolescente , Adulto , Estudos de Coortes , Anticoncepção/estatística & dados numéricos , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Comportamento Sexual , Adulto Jovem
2.
BMC Plant Biol ; 21(1): 359, 2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34353289

RESUMO

BACKGROUND: Plant height is an important architecture trait which is a fundamental yield-determining trait in crops. Variety with dwarf or semi-dwarf phenotype is a major objective in the breeding because dwarfing architecture can help to increase harvest index, increase planting density, enhance lodging resistance, and thus be suitable for mechanization harvest. Although some germplasm or genes associated with dwarfing plant type have been carried out. The molecular mechanisms underlying dwarfism in oilseed rape (Brassica napus L.) are poorly understood, restricting the progress of breeding dwarf varieties in this species. Here, we report a new dwarf mutant Bndwarf2 from our B. napus germplasm. We studied its inheritance and mapped the dwarf locus BnDWARF2. RESULTS: The inheritance analysis showed that the dwarfism phenotype was controlled by one semi-dominant gene, which was mapped in an interval of 787.88 kb on the C04 chromosome of B. napus by Illumina Brassica 60 K Bead Chip Array. To fine-map BnDWARF2, 318 simple sequence repeat (SSR) primers were designed to uniformly cover the mapping interval. Among them, 15 polymorphic primers that narrowed down the BnDWARF2 locus to 34.62 kb were detected using a F2:3 family population with 889 individuals. Protein sequence analysis showed that only BnaC04.BIL1 (BnaC04g41660D) had two amino acid residues substitutions (Thr187Ser and Gln399His) between ZS11 and Bndwarf2, which encoding a GLYCOGEN SYNTHASE KINASE 3 (GSK3-like). The quantitative real-time PCR (qRT-PCR) analysis showed that the BnaC04.BIL1 gene expressed in all tissues of oilseed rape. Subcellular localization experiment showed that BnaC04.BIL1 was localized in the nucleus in tobacco leaf cells. Genetic transformation experiments confirmed that the BnaC04.BIL1 is responsible for the plant dwarf phenotype in the Bndwarf2 mutants. Overexpression of BnaC04.BIL1 reduced plant height, but also resulted in compact plant architecture. CONCLUSIONS: A dominant dwarfing gene, BnaC04.BIL1, encodes an GSK3-like that negatively regulates plant height, was mapped and isolated. Our identification of a distinct gene locus may help to improve lodging resistance in oilseed rape.


Assuntos
Brassica napus/crescimento & desenvolvimento , Brassica napus/genética , Proteínas de Plantas/genética , Mapeamento Cromossômico , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Quinase 3 da Glicogênio Sintase/genética , Mutação , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Tabaco/genética
3.
Artigo em Inglês | MEDLINE | ID: mdl-34221095

RESUMO

Objectives: To evaluate the efficacy and/or safety of acupuncture therapy (AT) in quitting smoking. Methods: Randomized controlled trials (RCTs) were searched in PubMed, Cochrane Library, Embase, Web of Science, and Chinese Biomedical Database (CBM). We used Cochrane Collaborative Quality Assessment to assess the risk of bias. Bayesian network meta-analysis was utilized to evaluate the efficacy and safety of different interventions. Data analyses were conducted using WinBUGS 1.4.3, Stata 14, and RevMan 5.3.5 software. Results: A total of 2706 patients from 23 studies were included, involving 6 treatment arms. Network meta-analysis demonstrated that there was no significant difference in short-term abstinence rates or changes in Fagerstrom test for nicotine dependence (FTND) scores and daily smoking among these groups (AT, sham acupuncture therapy (SAT), auricular acupressure (AA), sham auricular acupressure (SAA), acupuncture plus auricular acupressure (APAA), and nicotine replacement therapy (NRT)). However, there was a significant difference between SAA and AA with risk ratio (RR) of 2.49 (95% CI 1.14, 5.97) in long-term abstinence rate. The probabilistic ranking results showed that APAA and AA were superior to other interventions in the comparison of abstinence rates. There was no obvious inconsistency between the direct comparison and indirect comparison, using the consistency test. Conclusion: AA was superior to SAA in smoke quitting, but there was no difference among other interventions in long-term truncation rates. There was no difference in short-term abstinence rates among these selected groups. We need large sample RCTs to clarify the advantages of interventions such as APAA and AA. In addition, reporting of adverse events that may occur during treatment also should be enhanced to complement evidence-based medicine. The trial is registered with PROSPERO CRD42020164712.

4.
Int J Biol Sci ; 17(5): 1361-1381, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33867852

RESUMO

Colorectal cancer (CRC) is the third most commonly diagnosed malignancy and the second leading cause of cancer death, which accounts for approximately 10% of all new cancer cases worldwide. Surgery is the main method for treatment of early-stage CRC. However, it is not effective for most metastatic tumors, and new treatment and diagnosis strategies need to be developed. Photosensitizers (PSs) play an important role in the treatment of CRC. Phototherapy also has a broad prospect in the treatment of CRC because of its low invasiveness and low toxicity. However, most PSs are associated with limitations including poor solubility, poor selectivity and high toxicity. The application of nanomaterials in PSs has added many advantages, including increased solubility, bioavailability, targeting, stability and low toxicity. In this review, based on phototherapy, we discuss the characteristics and development progress of PSs, the targeting of PSs at organ, cell and molecular levels, and the current methods of optimizing PSs, especially the application of nanoparticles as carriers in CRC. We introduce the photosensitizer (PS) targeting process in photodynamic therapy (PDT), the damage mechanism of PDT, and the application of classic PS in CRC. The action process and damage mechanism of photothermal therapy (PTT) and the types of ablation agents. In addition, we present the imaging examination and the application of PDT / PTT in tumor, including (fluorescence imaging, photoacoustic imaging, nuclear magnetic resonance imaging, nuclear imaging) to provide the basis for the early diagnosis of CRC. Notably, single phototherapy has several limitations in vivo, especially for deep tumors. Here, we discuss the advantages of the combination therapy of PDT and PTT compared with the single therapy. At the same time, this review summarizes the clinical application of PS in CRC. Although a variety of nanomaterials are in the research and development stage, few of them are actually on the market, they will show great advantages in the treatment of CRC in the near future.

5.
Int J Clin Pract ; 75(7): e14192, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33792114

RESUMO

AIMS: To compare patient mortality and technique survival between patients undergoing assisted peritoneal dialysis (aPD) and self-care peritoneal dialysis (sPD). METHODS: Patients who underwent peritoneal dialysis (PD) at the dialysis center of Second Affiliated Hospital of Soochow University from January 1, 2012 to December 31, 2016, were included and followed to December 31, 2019. Subjects were divided into aPD and sPD groups according to whether the patient could independently complete the PD procedure. Differences in mortality and technique failure rates were compared using competing risk analysis. RESULTS: A total of 384 patients were included in this study, with 274 patients in the sPD group and 110 patients in the aPD group. The multivariate competing risk regression analysis revealed that age (HR 1.03,95%CI 1.01-1.05, P < .001), aPD (HR 1.84,95%CI 1.10-3.08, P = .02), diabetes (HR 1.51, 95%CI 1.00-2.30, P = .05), residual renal function (HR 0.89, 95%CI 0.82-0.97, P = .005) and serum albumin level (HR 0.92, 95% CI 0.89-0.96, P < .001) were the independent risk factors for mortality. Besides, technique failure in aPD patients was lower than in the sPD group (HR 0.85, 95% CI 0.68-0.97, P = .03). CONCLUSION: These results found that aPD patients had higher mortality rates but lower technique failure rates than sPD patients. Higher mortality in aPD is probably related to the negative selection of the more comorbid patients. ​ ​.


Assuntos
Falência Renal Crônica , Diálise Peritoneal Ambulatorial Contínua , Diálise Peritoneal , Humanos , Falência Renal Crônica/terapia , Análise Multivariada , Estudos Retrospectivos , Medição de Risco , Fatores de Risco
6.
Thorac Cancer ; 12(6): 752-759, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33481352

RESUMO

BACKGROUND: The role of sine oculis homeobox 4 (SIX4) has been found in some malignant tumors. However, there have been few studies on the function of SIX4 in esophageal squamous cell carcinoma (ESCC). This study aimed to explore the regulatory mechanism of SIX4 in ESCC. METHODS: RT-qPCR and Western blot analysis were used to measure mRNA and protein expression. The function of SIX4 was investigated using CCK-8, colony formation, flow cytometry, wound healing and transwell assays. A mouse xenograft tumor assay was designed to perform in vivo experiments. RESULTS: SIX4 was upregulated in ESCC and indicated poor clinical outcomes in ESCC patients. Functionally, knockdown of SIX4 inhibited cell proliferation and induced apoptosis in ESCC. In addition, the silencing of SIX4 inhibited cell migration, invasion and EMT in ESCC. More importantly, upregulation of SIX4 could activate the PI3K/AKT pathway in ESCC cells and promote tumor growth in vivo. CONCLUSIONS: Upregulation of SIX4 indicates poor clinical outcomes in ESCC patients and promotes tumor growth and cell metastasis in ESCC.

7.
Chem Commun (Camb) ; 57(3): 284-301, 2021 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-33300514

RESUMO

As a photophysical phenomenon, aggregation-induced emission (AIE) was proposed by Tang in 2001. Due to their excellent fluorescence emission performance, AIEgens and AIE-based fluorescence materials have shown great application potential in a wide range of science fields. Hence, exploring new AIEgens and construction of novel AIE materials are especially vital. In addition, as a new class of macrocyclic hosts, pillararenes have shown excellent performance in supramolecular chemistry. Interestingly, pillararenes also exhibited fairly bright application prospects in the AIE area: firstly, some research studies suggested that pillararenes could serve as a novel AIEgen with considerable fluorescence emission in the aggregated state; moreover, they could also participate in the construction of AIE materials and have potential application in various areas. In this review, we summarised the recent development of pillararene-based AIE materials from the following aspects: pillararenes as novel AIEgens, the TPE functionalized pillararene-based AIE materials, the pillararene-based AIE materials constructed by supramolecular assembly, and the functionalized pseudo-pillararene-based AIE materials. It is hoped that this feature article will attract increasing attention and pave a new way for the development and application of pillar[n]arene-based AIE materials in more fields.

8.
Genome Biol ; 21(1): 291, 2020 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-33267872

RESUMO

BACKGROUND: Tetracentron sinense is an endemic and endangered deciduous tree. It belongs to the Trochodendrales, one of four early diverging lineages of eudicots known for having vesselless secondary wood. Sequencing and resequencing of the T. sinense genome will help us understand eudicot evolution, the genetic basis of tracheary element development, and the genetic diversity of this relict species. RESULTS: Here, we report a chromosome-scale assembly of the T. sinense genome. We assemble the 1.07 Gb genome sequence into 24 chromosomes and annotate 32,690 protein-coding genes. Phylogenomic analyses verify that the Trochodendrales and core eudicots are sister lineages and showed that two whole-genome duplications occurred in the Trochodendrales approximately 82 and 59 million years ago. Synteny analyses suggest that the γ event, resulting in paleohexaploidy, may have only happened in core eudicots. Interestingly, we find that vessel elements are present in T. sinense, which has two orthologs of AtVND7, the master regulator of vessel formation. T. sinense also has several key genes regulated by or regulating TsVND7.2 and their regulatory relationship resembles that in Arabidopsis thaliana. Resequencing and population genomics reveals high levels of genetic diversity of T. sinense and identifies four refugia in China. CONCLUSIONS: The T. sinense genome provides a unique reference for inferring the early evolution of eudicots and the mechanisms underlying vessel element formation. Population genomics analysis of T. sinense reveals its genetic diversity and geographic structure with implications for conservation.

9.
Front Med (Lausanne) ; 7: 541537, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33282883

RESUMO

This article investigated the effects of the traditional Chinese medicine (TCM) herbal recipe, Bushen Yutai, on in vitro fertilization (IVF) patients subjected to mild ovarian stimulation. Two hundred nineteen infertile patients were randomly divided into 2 groups: the control group and herbal treatment group. By studying, we found estrogen levels (E2) on the human chorionic gonadotropin (hCG) triggering day were significantly lower in the control group (P < 0.05), with positive blood flow being less detected by ultrasound scanning on both the day of hCG triggering and day of fresh embryo transfer for the control group (P < 0.05). Additionally, the blood flow index, retroactive and proactive inhibition, was higher in the control group, whereas the fertilization rate and number of high-quality embryos in the control group were lower than the control TCM experimental group (P < 0.01). The expression levels of the endometrial receptivity gene, vascular endothelial growth factor (VEGF), were lower in the control group vs. the TCM experimental group on the day of fresh embryo transfer (P < 0.05), whereas the rate of fresh embryo transfer in the control group was lower than the TCM experimental group (P < 0.05). In conclusion, the TCM could increase the E2 during the IVF stage, with a higher number of oocytes and higher-quality embryos. It also improved the endometrium and increased the level of VEGF gene expression. By enhancing the fresh embryo transfer rate in a minimal ovarian stimulation protocol and by improving the clinical pregnancy and ongoing pregnancy rates, the Bushen Yutai recipe could be able to increase fresh embryo transfer and higher-quality embryos.

10.
Chem Commun (Camb) ; 56(92): 14416-14419, 2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33146176

RESUMO

The transition-metal-catalyzed carboxylation of aryl and vinyl chlorides with CO2 is rarely studied, and has been achieved only with a Ni catalyst or combination of palladium and photoredox. In this work, the cobalt-catalyzed carboxylation of aryl and vinyl chlorides and bromides with CO2 has been developed. These transformations proceed under mild conditions and exhibit a broad substrate scope, affording the corresponding carboxylic acids in good to high yields.

11.
Medicine (Baltimore) ; 99(33): e21451, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32871992

RESUMO

BACKGROUND: Mental health is closely related to the occurrence of hypertension, particularly the prognosis of hypertension patients. The role of psychotherapy in the occurrence, development, prevention, and prognosis of hypertension, remains to be clarified. METHODS/DESIGN: We will conduct a prospective, double-blind, randomized, multiple-centers study. Eighty patients enrolled in this trial will be randomized at 1:1 ratio. The primary endpoint is will be the reduction of the patient psychological scale (PHQ-9) score. Secondary endpoints will be the drop in blood pressure, awareness of physical and mental health and self-efficacy scale. Measurements will be performed at baseline, 5-week (questionnaires only), 10-week (primary endpoint), using the Anxiety Screening Questionnaire (GAD-7) and Depression Scale (PHQ-9). Data analysis will be carried out using the SPSS v.25 software assuming a level of significance of 5%. Results will be analyzed using multilevel, regression analysis and hierarchical linear models. DISCUSSION: We hope to provide some insight in the understanding the underlying mechanism of the novel mindfulness in the management of hypertension related psychological stress/disturbance, and will enable us to develop novel approach to manage essential hypertension and its related psychological disorders. CLINICAL TRIAL REGISTRY:: http://www.chictr.org.cn (ChiCTR1900028258).


Assuntos
Transtornos de Ansiedade/psicologia , Transtornos de Ansiedade/terapia , Transtorno Depressivo/psicologia , Transtorno Depressivo/terapia , Hipertensão/psicologia , Hipertensão/terapia , Psicoterapia/métodos , Método Duplo-Cego , Humanos , Prognóstico , Estudos Prospectivos , Escalas de Graduação Psiquiátrica , Ensaios Clínicos Controlados Aleatórios como Assunto
12.
Life Sci ; 259: 118380, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32898524

RESUMO

AIMS: Benign prostatic hyperplasia (BPH) is a progressive disease, which severely affects men's health. Here, we sought to analyze the functions and mechanism of action of the tripartite motif protein 52 (TRIM52), a novel prostate basal cell biomarker in BPH. MATERIALS AND METHODS: Immunohistochemistry assay was performed in sectioned human BPH tissues, BPH-1 cells, and prostate RWPE-1 cells, to detect the expressions of TRIM52 and NF-κB. Western blotting and qRT-PCR analyses were conducted to measure the relative protein and mRNA expression levels, respectively. Further, lentiviral transfection was performed in BPH-1 and RWPE-1 cells to study the overexpression and siRNA knockdown of TRIM52. Dual-luciferase reporter assay was applied to evaluate the relationship between NF-κB and TRIM52. Furthermore, CCK-8 assay and flow cytometry were employed to analyze cell proliferation and apoptosis. KEY FINDINGS: TRIM52 and NF-κB levels were elevated in BPH tissues, and TRIM52 expression positively correlated with NF-κB expression. TRIM52 silencing suppressed the growth of BPH-1 cells and decreased the promoter activity of NF-κB. Moreover, the NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC), suppressed TRIM52-induced proliferation of RWPE-1 cells and inhibited NF-κB promoter activity in oeTRIM52 transfected RWPE-1 cells. Silencing TRIM52 also inhibited TRAF2 ubiquitination in BPH-1 cells. Further, NF-κB promoter activity in siNC transfected cells was enhanced by the recombinant protein TNF-α and inhibited by siTRIM52. SIGNIFICANCE: TRIM52 accelerated the growth of BPH-1 cells by upregulating NF-κB, and TRIM52 could promote TRAF2 ubiquitination. These findings might contribute to the understanding of the biological functions and action mechanisms of TRIM52 in BPH.


Assuntos
NF-kappa B/metabolismo , Hiperplasia Prostática/metabolismo , Fator 2 Associado a Receptor de TNF/metabolismo , Proteínas com Motivo Tripartido/metabolismo , Western Blotting , Progressão da Doença , Citometria de Fluxo , Humanos , Masculino , Hiperplasia Prostática/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ubiquitinação
13.
Ren Fail ; 42(1): 807-817, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32781861

RESUMO

OBJECTIVES: To investigate the effects of climatic variables on peritoneal dialysis-associated peritonitis (PDAP) among patients receiving PD, such as seasonal variations in temperature and humidity. METHODS: A retrospective analysis was performed on PD patients, from 1 January 2011, to 31 December 2019. We evaluated the influence of seasonal factors on peritonitis rates and outcomes. RESULTS: Over the 9-year study period, 667 peritonitis episodes occurred, in 401 PD patients. Diarrhea-associated peritonitis occurred more frequently in summer compared with other seasons. Eating raw and cold food was identified as the primary cause of peritonitis in the summer. More peritonitis episodes occurred during summer. The peritonitis rate associated with gram-negative bacteria (p = 0.050) during summer was higher than those in all other seasons. The gram-negative bacterial peritonitis rate was positively correlated with monthly mean temperature (r = 0.504, p < 0.01) and humidity (r = 0.561, p < 0.01). A similar trend was observed for Enterobacterial peritonitis (temperature: r = 0.518, p < 0.01; humidity: r = 0.456, p = 0.001). Logistic regression analysis showed that summer was a risk factor for peritonitis (p = 0.041). Peritonitis prognosis during summer was significantly worse than those for all other seasons (p = 0.037). CONCLUSIONS: Seasonal variations exist in the incidence of dialysis-associated peritonitis, with peak incidents caused by gram-negative bacteria in the summer. High average temperature and humidity are associated with significant increases in the gram-negative bacteria and Enterobacterial peritonitis rates. Peritonitis prognosis during summer is worse.


Assuntos
Infecções por Enterobacteriaceae/epidemiologia , Infecções por Bactérias Gram-Negativas/epidemiologia , Diálise Peritoneal/efeitos adversos , Peritonite/epidemiologia , Estações do Ano , Adulto , Idoso , Antibacterianos/uso terapêutico , China/epidemiologia , Infecções por Enterobacteriaceae/etiologia , Feminino , Infecções por Bactérias Gram-Negativas/etiologia , Humanos , Incidência , Falência Renal Crônica/epidemiologia , Falência Renal Crônica/terapia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Peritonite/etiologia , Estudos Retrospectivos
14.
Anal Chem ; 92(14): 9908-9915, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32608237

RESUMO

Evaluating the deterioration state of archeological wood is obligatory before the preservation of archeological wooden artifacts. Herein, a nondestructive, accurate, and rapid methodology is first developed via direct analysis in real time-mass spectrometry (DART-MS) with chemometrics to classify archeological wood and recent wood into 3 groups according to their deterioration states. As water in wooden artifacts probably affected the ion fragmentation process during DART-MS, ions responsible for evaluating the deterioration state were separately screened toward waterlogged archeological wood and dried archeological wood by partial least-squares discriminant analysis (PLS-DA). The well-defined separation of severely decayed archeological wood, moderately decayed archeological wood and recent wood was revealed in PLS-DA models. Twenty and 27 wood fragment ions were further screened as key variables to evaluate the deterioration state of waterlogged archeological wood and dried archeological wood, respectively. They were tentatively identified as ions of lignin monomeric compositions, lignin dimers, lignin trimers, and oligosaccharides. Results strongly suggested that differences in the structure and relative abundances of wood cell wall components accounts for the evaluation of deterioration state by DART-MS coupled to chemometrics. PLS-DA models provided R2Y = 0.836, Q2 = 0.817, and R2Y = 0.754, Q2 = 0.682 were then established separately using mass spectral fingerprints of respective potential predictive wood fragment ions. Furthermore, archeological woods, consisting of Castanopsis, Quercus, Idesia, Populus, and Cunninghamia species and with an average MWC range of 103-465%, were used as an external validation set and evaluated with the methodology developed herein and the MWC criteria. Results showed that DART-MS coupled to chemometrics could accurately predict the inhomogeneous deterioration states of archeological wooden artifacts and avoid the interference of inorganic deposits, in comparison with the MWC criteria.

15.
Front Chem ; 8: 352, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32411674

RESUMO

Low-dimensional organic-inorganic hybrid materials have attracted tremendous attentions due to their fascinating properties as emerging star materials for light-emitting applications. Taking advantage of their rich chemical composition and structural diversity, here, a novel lead-free organic-manganese halide compound, (1-mPQBr)2MnBr4 (1-mPQ = 1-methylpiperazine, 1-C5H14N2) with zero-dimensional structure has been rationally designed and successfully synthesized through solvent-evaporation method. Systematical characterizations were carried out to investigate the structure, thermal and photophysical properties. The (1-mPQBr)2MnBr4 was found to crystallized into an orthorhombic crystal (P212121) with lattice parameters of a = 8.272(6) Å, b = 15.982(10) Å and c = 17.489(11) Å. The structure consists of isolated [MnBr4]2- clusters and free Br- ions as well as [C5H14N2]2+ molecules. Thermal analysis indicates that it is stable up to 300°C. Upon ultraviolet photoexcitation, the (1-mPQBr)2MnBr4 exhibits intense green emission centered at 520 nm with a narrow full width at half-maximum of 43 nm at room temperature, which should be assigned to the spin-forbidden internal transition (4T1(G) to 6A1) of tetrahedrally coordinated Mn2+ ions. The superior photoluminescence properties coupled with facile and efficient synthesis method of this material suggest its considerable promise to be utilized as light-emitting materials.

17.
Plants (Basel) ; 9(2)2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32054100

RESUMO

Pit membranes in between neighboring conduits of xylem play a crucial role in plant water transport. In this review, the morphological characteristics, chemical composition and mechanical properties of bordered pit membranes were summarized and linked with their functional roles in xylem hydraulics. The trade-off between xylem hydraulic efficiency and safety was closely related with morphology and properties of pit membranes, and xylem embolism resistance was also determined by the pit membrane morphology and properties. Besides, to further investigate the effects of bordered pit membranes morphology and properties on plant xylem hydraulic functions, here we modelled three-dimensional structure of bordered pit membranes by applying a deposition technique. Based on reconstructed 3D pit membrane structures, a virtual fibril network was generated to model the microflow pattern across inter-vessel pit membranes. Moreover, the mechanical behavior of intervessel pit membranes was estimated from a single microfibril's mechanical property. Pit membranes morphology varied among different angiosperm and gymnosperm species. Our modelling work suggested that larger pores of pit membranes do not necessarily contribute to major flow rate across pit membranes; instead, the obstructed degree of flow pathway across the pit membranes plays a more important role. Our work provides useful information for studying the mechanism of microfluid flow transport across pit membranes and also sheds light on investigating the response of pit membranes both at normal and stressed conditions, thus improving our understanding on functional roles of pit membranes in xylem hydraulic function. Further work could be done to study the morphological and mechanical response of bordered pit membranes under different dehydrated conditions, as well as the related microflow behavior, based on our constructed model.

18.
Quant Imaging Med Surg ; 10(1): 220-232, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31956544

RESUMO

Background: Neuropathological studies have shown that the hippocampus is affected in Parkinson's disease (PD) with cognitive impairment. Our goal was to assess the longitudinal volume change of different hippocampal subfields in PD patients with and without cognitive decline using magnetic resonance imaging (MRI). Methods: A total of 28 nondemented PD patients and 27 neurologically unimpaired elderly controls were enrolled in this study, and three-dimensional (3D) T1-weighted MRI was performed. All PD patients that were followed up and rescanned after 2 years were divided into two groups: PD without cognitive decline (n=15) and PD with cognitive decline (n=13). A Bayesian model implemented in FreeSurfer was used to segment the hippocampal subfields automatically. Scale for global cognitive status included the Mini Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). Results: In the cross sectional study, the bilateral hippocampal volume was smaller in PD patients compared to healthy controls, and the bilateral subiculum, CA2/3, CA4, and molecular layer (ML) subfields, and the right granule cell layer of the dentate gyrus (GC-DG) subfield, were significantly decreased in the PD patients. Significant correlations were found between the MoCA score and total hippocampus volume in PD patients. In the follow-up group, bilateral CA4, ML, and GC-DG subfields, and left CA2/3 and right presubiculum subfields, were significantly smaller in PD patients with cognitive decline compared to PD patients without cognitive decline. Significant correlations were found between the longitudinal change of the MMSE or MoCA scores and percent change rate of total bilateral hippocampal, bilateral ML, and right CA4 in all PD patients. Conclusions: Our results demonstrated the selective regional vulnerability of the hippocampus in the progression of PD. These findings corroborate neuropathological findings and add novel information about the involvement of the hippocampus in the cognitive dysfunction of PD.

19.
Nat Commun ; 11(1): 323, 2020 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-31949152

RESUMO

The two-dimensional (2D) Ruddlesden-Popper organic-inorganic halide perovskites such as (2D)-phenethylammonium lead iodide (2D-PEPI) have layered structure that resembles multiple quantum wells (MQW). The heavy atoms in 2D-PEPI contribute a large spin-orbit coupling that influences the electronic band structure. Upon breaking the inversion symmetry, a spin splitting ('Rashba splitting') occurs in the electronic bands. We have studied the spin splitting in 2D-PEPI single crystals using the circular photogalvanic effect (CPGE). We confirm the existence of Rashba splitting at the electronic band extrema of 35±10 meV, and identify the main inversion symmetry breaking direction perpendicular to the MQW planes. The CPGE action spectrum above the bandgap reveals spin-polarized photocurrent generated by ultrafast relaxation of excited photocarriers separated in momentum space. Whereas the helicity dependent photocurrent with below-gap excitation is due to spin-galvanic effect of the ionized spin-polarized excitons, where spin polarization occurs in the spin-split bands due to asymmetric spin-flip.

20.
ChemSusChem ; 2019 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-31709721

RESUMO

The exceptional structural tunability of organic metal halides endows them with fascinating electronic and photophysical properties, providing much scope for applications. In this work, single crystals of the organic metal halide (C4 H9 NH3 )2 MnI4 are found to show reversible thermo-induced luminescent chromism within a wide temperature range. The (C4 H9 NH3 )2 MnI4 single crystal exhibits two emission peaks at 550 and 672 nm, which are assigned to a d-d transition of Mn2+ -centered tetrahedra and self-trapped excitons, respectively. The temperature-dependent emission color change is attributed to the thermo-induced trapping and detrapping process of the self-trapped exciton. (C4 H9 NH3 )2 MnI4 exhibits a maximum photoluminescence quantum efficiency of up to 68 % at 70 °C. The disclosed interacted photoluminescence decay mechanisms may prove useful for the further design of organic metal halides for optical thermometry.

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