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1.
J Am Chem Soc ; 146(28): 19286-19294, 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-38956888

RESUMO

As one of the most powerful trifluoromethylation reagents, (trifluoromethyl)trimethylsilane (TMSCF3) has been widely used for the synthesis of fluorine-containing molecules. However, to the best of our knowledge, the simultaneous incorporation of both TMS- and CF3- groups of this reagent onto the same carbon of the products has not been realized. Herein, we report an unprecedented SmI2/Sm promoted deoxygenative difunctionalization of amides with TMSCF3, in which both silyl and trifluoromethyl groups are incorporated into the final product, yielding α-silyl-α-trifluoromethyl amines with high efficiency. Notably, the silyl group could be further transformed into other functional groups, providing a new method for the synthesis of α-quaternary α-CF3-amines.

2.
J Med Virol ; 96(1): e29395, 2024 01.
Artigo em Inglês | MEDLINE | ID: mdl-38235782

RESUMO

People living with HIV (PLWH) are particularly vulnerable to SARS-CoV-2. This multicentre prospective cohort study evaluated the long-term immunogenicity and safety of a third homologous dose of Sinovac CoronaVac in PLWH in China. A total of 228 PLWH and 127 HIV-negative controls were finally included and followed up for 6 months. Fewer participants reported mild or moderate adverse reactions, and no serious adverse events were observed. The median levels of neutralizing antibodies (nAbs) and immunoglobulin G against the receptor-binding domain of the spike protein (S-IgG) in PLWH (655.92 IU/mL, IQR: 175.76-1663.55; 206.83 IU/mL, IQR: 85.20-397.82) were comparable to those in control group (1067.16 IU/mL, IQR: 239.85-1670.83; 261.70 IU/mL, IQR: 77.13-400.75), and reached their peak at 4 weeks, exhibiting a delayed peak pattern compared to the 2-week peak in control group. After then, the immune titres gradually decreased over time, but most participants still maintained positive seroconversion at the 6-month mark. Multivariable generalized estimating equation analysis indicated that CD4+T cell count, HIV viral load, and antiretroviral therapy (ART) were independent factors strongly associated with immune response (each p < 0.05). We suggested that PLWH should maintain well-controlled HIV status through ART and receive timely administration of the second booster dose for optimal protection.


Assuntos
Anticorpos Neutralizantes , Anticorpos Antivirais , Vacinas contra COVID-19 , Vacinas de Produtos Inativados , Humanos , Estudos Prospectivos , China , Contagem de Linfócito CD4 , Imunogenicidade da Vacina
3.
Plant Cell Environ ; 47(5): 1625-1639, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38282386

RESUMO

The circadian clock plays multiple functions in the regulation of plant growth, development and response to various abiotic stress. Here, we showed that the core oscillator component late elongated hypocotyl (LHY) was involved in rice response to salt stress. The mutations of OsLHY gene led to reduced salt tolerance in rice. Transcriptomic analyses revealed that the OsLHY gene regulates the expression of genes related to ion homeostasis and the abscisic acid (ABA) signalling pathway, including genes encoded High-affinity K+ transporters (OsHKTs) and the stress-activated protein kinases (OsSAPKs). We demonstrated that OsLHY directly binds the promoters of OsHKT1;1, OsHKT1;4 and OsSAPK9 to regulate their expression. Moreover, the ossapk9 mutants exhibited salt tolerance under salt stress. Taken together, our findings revealed that OsLHY integrates ion homeostasis and the ABA pathway to regulate salt tolerance in rice, providing insights into our understanding of how the circadian clock controls rice response to salt stress.


Assuntos
Oryza , Tolerância ao Sal , Tolerância ao Sal/genética , Hipocótilo/metabolismo , Oryza/fisiologia , Estresse Salino , Homeostase , Estresse Fisiológico , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Ácido Abscísico/metabolismo
4.
J Nanobiotechnology ; 22(1): 19, 2024 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-38178140

RESUMO

Periodontitis is a chronic inflammatory disease caused by the local microbiome and the host immune response, resulting in periodontal structure damage and even tooth loss. Scaling and root planning combined with antibiotics are the conventional means of nonsurgical treatment of periodontitis, but they are insufficient to fully heal periodontitis due to intractable bacterial attachment and drug resistance. Novel and effective therapeutic options in clinical drug therapy remain scarce. Nanotherapeutics achieve stable cell targeting, oral retention and smart release by great flexibility in changing the chemical composition or physical characteristics of nanoparticles. Meanwhile, the protectiveness and high surface area to volume ratio of nanoparticles enable high drug loading, ensuring a remarkable therapeutic efficacy. Currently, the combination of advanced nanoparticles and novel therapeutic strategies is the most active research area in periodontitis treatment. In this review, we first introduce the pathogenesis of periodontitis, and then summarize the state-of-the-art nanotherapeutic strategies based on the triple concerto of antibacterial activity, immunomodulation and periodontium regeneration, particularly focusing on the therapeutic mechanism and ingenious design of nanomedicines. Finally, the challenges and prospects of nano therapy for periodontitis are discussed from the perspective of current treatment problems and future development trends.


Assuntos
Periodontite , Humanos , Periodontite/tratamento farmacológico , Periodonto , Antibacterianos/uso terapêutico , Regeneração , Imunomodulação , Imunidade
5.
BMC Biol ; 21(1): 68, 2023 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-37013569

RESUMO

BACKGROUND: The accumulation of fatty acids in plants covers a wide range of functions in plant physiology and thereby affects adaptations and characteristics of species. As the famous woody oilseed crop, Acer truncatum accumulates unsaturated fatty acids and could serve as the model to understand the regulation and trait formation in oil-accumulation crops. Here, we performed Ribosome footprint profiling combing with a multi-omics strategy towards vital time points during seed development, and finally constructed systematic profiling from transcription to proteomes. Additionally, we characterized the small open reading frames (ORFs) and revealed that the translational efficiencies of focused genes were highly influenced by their sequence features. RESULTS: The comprehensive multi-omics analysis of lipid metabolism was conducted in A. truncatum. We applied the Ribo-seq and RNA-seq techniques, and the analyses of transcriptional and translational profiles of seeds collected at 85 and 115 DAF were compared. Key members of biosynthesis-related structural genes (LACS, FAD2, FAD3, and KCS) were characterized fully. More meaningfully, the regulators (MYB, ABI, bZIP, and Dof) were identified and revealed to affect lipid biosynthesis via post-translational regulations. The translational features results showed that translation efficiency tended to be lower for the genes with a translated uORF than for the genes with a non-translated uORF. They provide new insights into the global mechanisms underlying the developmental regulation of lipid metabolism. CONCLUSIONS: We performed Ribosome footprint profiling combing with a multi-omics strategy in A. truncatum seed development, which provides an example of the use of Ribosome footprint profiling in deciphering the complex regulation network and will be useful for elucidating the metabolism of A. truncatum seed oil and the regulatory mechanisms.


Assuntos
Acer , Ácidos Graxos , Ácidos Graxos/metabolismo , Transcriptoma , Perfilação da Expressão Gênica , Acer/genética , Acer/metabolismo , Ribossomos/metabolismo , Sementes/genética , Regulação da Expressão Gênica de Plantas
6.
J Biochem Mol Toxicol ; 37(3): e23273, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36541330

RESUMO

Bisphenol S (BPS) is an environmental endocrine disruptor widely used in industrial production. BPS induces oxidative stress and exhibits male reproductive toxicity in mice, but the mechanisms by which BPS impairs steroid hormone synthesis are not fully understood. Nuclear factor erythroid 2-related factor 2(Nrf2)/HO-1 signaling is a key pathway in improving cellular antioxidant defense capacities. Therefore, this study explored the effects of exposure to BPS on testosterone synthesis in adult male mice and its mechanisms with regard to the Nrf2/HO-1 signaling pathway. Adult male C57BL/6 mice were orally exposed to BPS (2, 20, and 200 mg/kg BW) with sesame oil as a vehicle (0.1 ml/10 g BW) per day for 28 consecutive days. The results showed that compared with the control group, serum testosterone levels were substantially reduced in the 20 and 200 mg/kg BPS treatment groups, and testicular testosterone levels were reduced in all BPS treatment groups. These changes were accompanied by a prominent decrease in the expression levels of testosterone synthesis-related enzymes (STAR, CYP11A1, CYP17A1, HSD3B1, and HSD17B3) in the mouse testis. In addition, BPS induced oxidative stress in the testis by upregulating the messenger RNA and protein levels of Keap1 and downregulating the levels of Nrf2, HO-1, and downstream antioxidant enzymes (CAT, SOD1, and Gpx4). In summary, our results indicate that exposure of adult male mice to BPS can inhibit Nrf2/HO-1 signaling and antioxidant enzyme activity, which induces oxidative stress and thereby may impair testosterone synthesis in testicular tissues, leading to reproductive damage.


Assuntos
Fator 2 Relacionado a NF-E2 , Testosterona , Masculino , Camundongos , Animais , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Antioxidantes/farmacologia , Camundongos Endogâmicos C57BL , Testículo/metabolismo , Estresse Oxidativo , Transdução de Sinais
7.
BMC Public Health ; 23(1): 2206, 2023 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-37946124

RESUMO

BACKGROUND: Most previous studies on women of childbearing age have focused on reproductive health and fertility intentions, and evidence regarding the comprehensive health status of women of childbearing age is limited. This study aimed to comprehensively examine the health status of women of childbearing age through a multi-method and multi-indicator evaluation, analyze the factors that influence their overall health, and provide sound recommendations for the improvement and promotion of healthy behaviors. METHODS: Data on women of childbearing age living in Shanxi Province were collected between September 2021 and January 2022 through online and offline surveys. The k-means algorithm was used to assess health-related patterns in women, and multivariate nonconditional logistic regression was used to assess the influencing factors of women's overall health. RESULTS: In total, 1,258 of 2,925 (43%) participants were classified as having a good health status in all five domains of the three health dimensions: quality of life, mental health, and illness. Multivariate logistic regression showed that education level, gynecological examination status, health status of family members, access to medical treatment, age, cooking preferences, diet, social support, hand washing habits, attitude toward breast cancer prevention, and awareness of reproductive health were significantly associated with different health patterns. CONCLUSIONS: The comprehensive health status of women of childbearing age in Shanxi Province is generally good; however, a large proportion of women with deficiencies in some dimensions remains. Since lifestyle greatly impacts women's health, health education on lifestyle and health-related issues should be strengthened.


Assuntos
Fertilidade , Qualidade de Vida , Feminino , Humanos , Estudos Transversais , China/epidemiologia , Análise por Conglomerados
8.
Pharm Dev Technol ; 28(1): 30-39, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36541732

RESUMO

A satisfactory clinical effect in treating periodontitis is often difficult to achieve by conventional non-surgical systemic drug delivery due to the narrow anatomical structure of the periodontal pocket and insufficient drug concentration at lesion sites. In addition, the feasibility of combating periodontal tissue lesions by restoring the alveolar bone and allowing collagen regeneration has not been fully explored. The objective of this study was to prepare a microemulsion integrating the anti-inflammatory and osteogenic active ingredients of baicalin and clove oil (BC-MEs). Then, the composite hydrogel obtained by mixing poloxamer 407 and 188 was used as the thermosensitive gel matrix to load BC-MEs and form a drug reservoir (Gel-BC-MEs) injectable in situ. Gel-BC-MEs exhibited a significant, sustained release of baicalin for 12 h, gelation temperature was 33.4 ± 0.36 °C, and pH was 5.45 ± 0.12. The experiment on a rat periodontitis model demonstrated that Gel-BC-MEs significantly improved periodontal tissue repair by collagen regeneration and osteogenesis by inhibiting osteoclast infiltration. This study proposes a novel strategy for periodontal tissue repair by enhancing the therapeutic potential of a microemulsion using an in situ nano-gel delivery system.


Assuntos
Periodontite , Ratos , Animais , Periodontite/tratamento farmacológico , Hidrogéis/química , Sistemas de Liberação de Medicamentos , Colágeno , Periodonto
9.
BMC Genomics ; 23(1): 746, 2022 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-36352370

RESUMO

BACKGROUND: So far, a lot of binning approaches have been intensively developed for untangling metagenome-assembled genomes (MAGs) and evaluated by two main strategies. The strategy by comparison to known genomes prevails over the other strategy by using single-copy genes. However, there is still no dataset with all known genomes for a real (not simulated) bacterial consortium yet. RESULTS: Here, we continue investigating the real bacterial consortium F1RT enriched and sequenced by us previously, considering the high possibility to unearth all MAGs, due to its low complexity. The improved F1RT metagenome reassembled by metaSPAdes here utilizes about 98.62% of reads, and a series of analyses for the remaining reads suggests that the possibility of containing other low-abundance organisms in F1RT is greatly low, demonstrating that almost all MAGs are successfully assembled. Then, 4 isolates are obtained and individually sequenced. Based on the 4 isolate genomes and the entire metagenome, an elaborate pipeline is then in-house developed to construct all F1RT MAGs. A series of assessments extensively prove the high reliability of the herein reconstruction. Next, our findings further show that this dataset harbors several properties challenging for binning and thus is suitable to compare advanced binning tools available now or benchmark novel binners. Using this dataset, 8 advanced binning algorithms are assessed, giving useful insights for developing novel approaches. In addition, compared with our previous study, two novel MAGs termed FC8 and FC9 are discovered here, and 7 MAGs are solidly unearthed for species without any available genomes. CONCLUSION: To our knowledge, it is the first time to construct a dataset with almost all known MAGs for a not simulated consortium. We hope that this dataset will be used as a routine toolkit to complement mock datasets for evaluating binning methods to further facilitate binning and metagenomic studies in the future.


Assuntos
Benchmarking , Metagenoma , Reprodutibilidade dos Testes , Metagenômica/métodos , Bactérias/genética
10.
BMC Plant Biol ; 22(1): 29, 2022 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-35026989

RESUMO

BACKGROUND: Acer truncatum (purpleblow maple) is a woody tree species that produces seeds with high levels of valuable fatty acids (especially nervonic acid). The species is admired as a landscape plant with high developmental prospects and scientific research value. The A. truncatum chloroplast genome has recently been reported; however, the mitochondrial genome (mitogenome) is still unexplored. RESULTS: We characterized the A. truncatum mitogenome, which was assembled using reads from PacBio and Illumina sequencing platforms, performed a comparative analysis against different species of Acer. The circular mitogenome of A. truncatum has a length of 791,052 bp, with a base composition of 27.11% A, 27.21% T, 22.79% G, and 22.89% C. The A. truncatum mitogenome contains 62 genes, including 35 protein-coding genes, 23 tRNA genes and 4 rRNA genes. We also examined codon usage, sequence repeats, RNA editing and selective pressure in the A. truncatum mitogenome. To determine the evolutionary and taxonomic status of A. truncatum, we conducted a phylogenetic analysis based on the mitogenomes of A. truncatum and 25 other taxa. In addition, the gene migration from chloroplast and nuclear genomes to the mitogenome were analyzed. Finally, we developed a novel NAD1 intron indel marker for distinguishing several Acer species. CONCLUSIONS: In this study, we assembled and annotated the mitogenome of A. truncatum, a woody oil-tree species producing nervonic acid. The results of our analyses provide comprehensive information on the A. truncatum mitogenome, which would facilitate evolutionary research and molecular barcoding in Acer.


Assuntos
Acer/genética , Acer/metabolismo , Ácidos Graxos Monoinsaturados/metabolismo , Genoma Mitocondrial , Óleos de Plantas/metabolismo , Árvores/genética , Variação Genética , Filogenia
11.
J Mol Recognit ; 35(12): e2985, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-35907782

RESUMO

Gout is an inflammatory joint disease caused by urate crystal deposition, which is associated with hyperuricemia. Gout will take place when the uric acid accumulates. Xanthine oxidase (XO) is a crucial enzyme in the formation of uric acid. Inhibiting XO is one of the means to ameliorate gout. Luteoloside is a kind of natural flavonoid, which has an excellent prospect for relieving gout. But there are few reports on the interaction mechanism between luteoloside and XO currently. In this study, the interaction mechanism between luteoloside and XO was explored using spectroscopy and molecular docking. The fluorescence spectroscopy results indicated that luteoloside could make the intrinsic fluorescence of XO quenched, and the binding constant between luteoloside and XO was (1.85 ± 0.22) × 103 L mol-1 at 298 K. The synchronous fluorescence spectroscopy results showed that the absorption peaks of Tyr and Trp shifted blue, and the hydrophobicity of the microenvironment increased. Moreover, CD spectra showed that α-helix of XO decreased, ß-sheet and ß-turn increased after adding luteoloside. The results of molecular docking analysis showed that XO could combine with luteoloside through hydrogen bonds and hydrophobic force. The results indicated that luteoloside could remarkably interact with XO. Insights into the interaction mechanism provide a necessary basis for the search for low-toxic natural products as targets of XO. HIGHLIGHTS: Luteoloside and xanthine oxidase was a strong binding mode and had only one binding site. Luteoloside could cause α-helix reduced, ß-sheet and ß-turn increased, and change the secondary structure of XO. The binding between luteoloside and xanthine oxidase was a spontaneous process. The main binding force was hydrophobic force between luteoloside and xanthine oxidase.


Assuntos
Gota , Xantina Oxidase , Humanos , Xantina Oxidase/química , Xantina Oxidase/metabolismo , Simulação de Acoplamento Molecular , Ácido Úrico , Inibidores Enzimáticos/farmacologia , Espectrometria de Fluorescência
12.
Opt Express ; 30(7): 11549-11562, 2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35473097

RESUMO

Hyperbolic metamaterials (HMMs) exhibit rich optical nonlinear responses for the epsilon-near-zero (ENZ) and anisotropy. In this study, we extract the time-dependent change in the effective permittivity of an Ag nanorod array under femtosecond pulses pumping around its ENZ wavelength. The transmittance and transient absorption spectra measured by s- and p-polarizations are used in the extraction process. We experimentally confirm the existence of an ultrafast recovery process with a relaxation time of 0.24 ps in the transient absorption spectra. The calculation based on the extracted nonlinear effective permittivity indicates that the ultrafast signal originates from the superposition of two slower recovery processes, with relaxation times of 0.74 ps and 1.19 ps, respectively. The results indicate that when the responses of two nonlinear processes have different signs and recovery speeds, their superposition may cause faster signal recovery in the combined process than in the two individual processes.

13.
Opt Express ; 30(18): 33136-33144, 2022 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-36242360

RESUMO

A multifunctional optical fiber sensor based upconversion luminescence (UCL) for synchronous temperature and curvature sensing was proposed. The sensor was fabricated by assembling UCL nanoparticles doped by rare earth (RE) ions in polydimethylsiloxane (PDMS) materials. Temperature measurements were achieved through the fluorescent intensity ratio (FIR) technique with the dual green UC luminescence generated. The fabricated sensor provided the temperature sensitivity of 714.82 K-1 with excellent linearity (R2=0.997) at a temperature range of 303 to 423 K. In the lower temperature region, temperature measurement based on the FIR technology is almost independent on the fluorescence intensity of a 525 nm emission peak. Hence, deformation produced by the sensor through bending results in detectable and reversible changes in its reflected light, allowing the curvature to be simultaneously measured. The sensor can monitor temperature and curvature simultaneously, providing a new optical alternative for multi-parameters monitoring in the future.

14.
Opt Express ; 30(26): 47485-47496, 2022 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-36558676

RESUMO

The process and condition of saturable absorption (SA) and reverse saturable absorption (RSA) of ultrafast nonlinear optics in metal nanoparticles are essential for applications including light generation, amplification, modulation, and switching. Here, we first discover and explore the multiple transformations (SA-RSA-SA) of ultrafast nonlinear absorption behavior of metal nanoparticles in femtosecond pulses. Correspondingly, the energy level model and fitting formula of multiple transformations are established to illustrate the process of optical response. The femtosecond transient absorption spectra provide information about their ultrafast dynamics process and vibrational mode, which further reveals the multiple transformation mechanisms of nonlinear absorption in gold nanobipyramids (Au-NBPs). Furthermore, Au-NBPs exhibit a significantly higher SA modulation depth up to 42% in the femtosecond, which is much higher than the reported values of other nanomaterials. Our results indicate that Au-NBPs can be used as broadband ultrafast Q-switching and mode-locking, and the conversion offers new opportunities for metal nanostructures in applications of optical switching.

15.
Opt Express ; 30(7): 10354-10366, 2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35473005

RESUMO

We first present the all-optical realization of a scalable super-resolved magnetic vortex core (MVC) by tightly focusing two modulated counter-propagating radially polarized doughnut Gaussian beams based on the vectoial diffraction theory and the inverse Faraday effect. It is shown that by imposing spiral phase plates (SPPs) on the incident vectorial beams, single three-dimensional (3D) super-resolved (λ3/22) MVC can be achieved in the 4π focusing setup, which is radically different from that produced with a single lens focusing. Furthermore, the light-induced MVC texture turns to be richer and more complex when the radially polarized beams are tailored by the SPPs and judiciously designed multi-ring filters all together. In this case, we are able to garner not only transverse super-resolved (0.447λ) MVC needle with an uniformly extended area (40λ) in the single lens focusing system, but also the multiple uniform 3D super-resolved (λ3/24) chain-like MVC cells in the 4π focusing system, thus giving rise to the tunable and scalable super-resolved MVC extension. The related physical mechanisms to trigger such peculiar magnetization polarization topologies are unraveled as well. These resultant achievements would pave the way for the integrated transfer and storage of optomagnetic information, atomic trapping, and beyond.

16.
Haematologica ; 107(4): 933-946, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-34134470

RESUMO

The GPIbT-VWF A1 domain interaction is essential for platelet tethering under high shear. Synergy between GPIbα and GPVI signaling machineries has been suggested previously, however its molecular mechanism remains unclear. We generated a novel GPIbα transgenic mouse (GpIbαΔsig/Δsig) by CRISPR-Cas9 technology to delete the last 24 residues of the GPIbα intracellular tail that harbors the 14-3-3 and phosphoinositide-3 kinase binding sites. GPIbαΔsig/Δsig platelets bound VWF normally under flow. However, they formed fewer filopodia on VWF/botrocetin in the presence of a oIIbI3 blocker, demonstrating that despite normal ligand binding, VWF-dependent signaling is diminished. Activation of GpIbαΔsig/Δsig platelets with ADP and thrombin was normal, but GpIbαΔsig/Δsig platelets stimulated with collagen-related-peptide (CRP) exhibited markedly decreased P-selectin exposure and eIIbI3 activation, suggesting a role for the GpIbaaintracellular tail in GPVI-mediated signaling. Consistent with this, while haemostasis was normal in GPIbαΔsig/Δsig mice, diminished tyrosine-phosphorylation, (particularly pSYK) was detected in CRP-stimulated GpIbαΔsig/Δsig platelets as well as reduced platelet spreading on CRP. Platelet responses to rhodocytin were also affected in GpIbαΔsig/Δsig platelets but to a lesser extent than those with CRP. GpIbαΔsig/Δsig platelets formed smaller aggregates than wild-type platelets on collagen-coated microchannels at low, medium and high shear. In response to both VWF and collagen binding, flow assays performed with plasma-free blood or in the presence of bIIbI3- or GPVI-blockers suggested reduced bIIbI3 activation contributes to the phenotype of the GpIbαΔsig/Δsig platelets. Together, these results reveal a new role for the intracellular tail of GPIbiiin transducing both VWF-GPIbGGand collagen-GPVI signaling events in platelets.


Assuntos
Plaquetas , Fator de von Willebrand , Animais , Plaquetas/metabolismo , Colágeno/metabolismo , Hemostasia , Humanos , Camundongos , Transdução de Sinais , Fator de von Willebrand/genética , Fator de von Willebrand/metabolismo
17.
Phys Chem Chem Phys ; 24(2): 955-965, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34918731

RESUMO

Intramolecular charge transfer (ICT) is an important factor in the nonlinear optical (NLO) properties of organic molecules. In order to study the effect of ICT on two-photon absorption (TPA) and excited-state absorption (ESA), three chalcone derivatives (1, 2 and 3) with different electron push-pull systems were designed and synthesized. The ICT performance of these chalcone derivatives depends on the electron push-pull systems and mainly includes ultrafast ICT in the femtosecond time domain and long-lived charge transfer state (CTS) in the picosecond time domain, which dominate the performance of molecular TPA and ESA respectively. Hole-electron analysis and femtosecond Z-scan experiment indicate that the TPA cross section of these chalcone derivatives can be effectively enhanced by introducing stronger ultra-fast ICT in the case of little difference in ground-state absorption and expanding the molecular π-conjugated structure. Transient absorption spectrum (TAS) experiments of these compounds in solvents of varying polarities were conducted to visualize the establishment of CTS. The local excited state (LES) and charge transfer state (CTS)-based ESA of these chalcone derivatives are extremely dependent on the strength of ICT. Our experimental results show that the superposition of LES and CTS by enhancing ICT performance can effectively improve the ESA, which offers us a practical method to improve the long-impulse response of organic materials.

18.
Molecules ; 27(11)2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35684501

RESUMO

A novel two-branched twistacene (PyDN) has been designed and synthesized for application on ultrafast optical limiting. This twistacene exhibits excellent two photon absorption and two photon absorption-induced excited singlet state absorption, which was systematically investigated with a femtosecond Z-scan experiment, transient absorption spectrum, and two-photon excited fluorescence experiments. The admirable two photon absorption is attributed to the high degree of π electron delocalization in twistacene which is caused by introduction of two strong donors. The excited singlet state absorption cooperates with two-photon absorption to provide an excellent ultrafast optical limiting behavior with high linear transmittance, where the thresholds are 2.3-5.3 mJ/cm2 in the spectral region of 532-800 nm of femtosecond laser and 133 mJ/cm2 for picosecond pulse at 532 nm. These thresholds are lower than that of most of the optical limiters reported previously, which indicates PyDN is a promising candidate for ultrafast optical limiting.

19.
Molecules ; 27(9)2022 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-35566197

RESUMO

The linear and nonlinear optical properties of two BODIPY derivatives, 1,7-Diphenyl-3,5-bis(9,9-dimethyl-9H-fluoren-2-yl)-boron-diuoride-azadipyrromethene (ZL-61) and 1,7-Diphenyl-3,5-bis(4-(1,2,2-triphenylvinyl)phenyl)-boron-diuoride-azadipyrromethene (ZL-22), were comprehensively investigated based on experimental and theoretical studies. It was found that both compounds show a strong two-photon absorption response in the near-infrared regime, and the two-photon-absorption cross-section values of ZL-61 and ZL-22 were determined to be 8321 GM and 1864 GM at 800 nm, respectively. The improvement of the two-photon absorption cross section in ZL-61 was attributed to the enhancement of the donor group, which was confirmed by transient absorption measurements and DFT calculation. Our results indicate that these BODIPY derivatives are a promising candidate for optical limiting and two-photon imaging applications.


Assuntos
Boro , Corantes Fluorescentes , Compostos de Boro , Porfobilinogênio/análogos & derivados
20.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 53(3): 426-430, 2022 May.
Artigo em Zh | MEDLINE | ID: mdl-35642150

RESUMO

Objective: To investigate the status quo of satisfaction with postgraduate education of clinical medicine and the influencing factors, so as to provide references for promoting improvements in the education model and the program quality of medical personnel training. Methods: A self-developed Clinical Medicine Postgraduate Program Quality Satisfaction Questionnaire was used to conduct a survey among 1907 postgraduate students of clinical medicine, and multivariate linear regression was used to analyze the influencing factors of postgraduate students' satisfaction with the quality of the program. Results: The overall satisfaction rate with the quality of the postgraduate clinical medical program was 81.44%, and the satisfaction score ranking of different dimensions from the highest to the lowest were 14 (12, 15) for supervisors, 19 (17, 22) for curriculum and instruction, 18 (16, 23) for management and survices, and 12 (10, 14) for research environment. The results of multiple stepwise regression analysis showed that the course evaluation method 〔partial regression coefficient ( Β)=0.048, 95% CI: 0.002-0.095, P=0.042〕 and teacher's teaching methodology ( Β=0.041, 95% CI: 0.010-0.072, P=0.011) of the dimension of curriculum and instruction, research outcomes ( B=0.033, 95% CI: 0.002-0.064, P=0.038) of the research environmrnt dimension, the supervisor's research ability ( B=0.035, 95% CI: 0.005-0.065, P=0.022) of the supervisor's ability dimention were important factors influencing the satisfaction with the quality of postgraduate clinical medical training. Conclusion: Satisfaction with the quality of postgraduate clinical medical training still needs further improvement. Regional medical schools should adopt diversified course evaluation methods, appropriately use modern instructional methods, increase investment in research funding, encourage research outputs, and help the supervisors continuously update their teaching and research philosophies.


Assuntos
Medicina Clínica , Faculdades de Medicina , Humanos , Satisfação Pessoal , Estudantes , Inquéritos e Questionários
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