Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 280
Filtrar
1.
Small ; 20(23): e2307086, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38155510

RESUMO

In analogy to the cell microenvironment in biology, understanding and controlling the active-material microenvironment (ME@AM) microstructures in battery electrodes is essential to the successes of energy storage devices. However, this is extremely difficult for especially high-capacity active materials (AMs) like sulfur, due to the poor controlling on the electrode microstructures. To conquer this challenge, here, a semi-dry strategy based on self-assembled nano-building blocks is reported to construct nest-like robust ME@AM skeleton in a solvent-and-stress-less way. To do that, poly(vinylidene difluoride) nanoparticle binder is coated onto carbon-nanofibers (NB@CNF) via the nanostorm technology developed in the lab, to form self-assembled nano-building blocks in the dry slurry. After compressed into an electrode prototype, the self-assembled dry-slurry is then bonded by in-situ nanobinder solvation. With this strategy, mechanically strong thick sulfur electrodes are successfully fabricated without cracking and exhibit high capacity and good C-rate performance even at a high AM loading (25.0 mg cm-2 by 90 wt% in the whole electrode). This study may not only bring a promising solution to dry manufacturing of batteries, but also uncover the ME@AM structuring mechanism with nano-binder for guiding the design and control on electrode microstructures.

2.
Opt Express ; 32(7): 11895-11906, 2024 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-38571027

RESUMO

Pure-quartic solitons (PQSs) have recently received increasing attention due to their energy-width scaling over the traditional soliton, which has expanded our understanding of soliton dynamics with high-order dispersion in nonlinear systems. Here, we numerically reveal the asynchronization and synchronization processes of the sub-pulse within the vector PQS molecule in a mode-locked fiber laser by solving the coupled Ginzburg-Landau equations. During the establishment of a vector PQS molecule, the repulsion, attraction, and finally stabilization processes have been observed. Specifically, sub-pulse disappearance, regeneration, and finally synchronization with the other pulses are also investigated. Our analysis of the pulse energy, time interval, and relative phase evolution dynamics with the round trip indicates that the asynchronization and synchronization within the vector PQS molecule associate tightly with the gain competition and the cross-phase modulation. Our findings provide insights into the internal mutual dynamics within the vector soliton molecule and offer guidance for the applications of PQS.

3.
Opt Lett ; 49(7): 1766-1769, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38560858

RESUMO

Dual-comb microscopy enables high-speed and high-precision optical sampling by simultaneously extracting both amplitude and phase information from the interference signals with frequency division multiplexing. In this Letter, we introduce a spatiotemporal encoding approach for dual-comb microscopy that overcomes previous limitations such as mechanical scanning, low sampling efficiency, and system complexity. By employing free-space angular-chirp-enhanced delay (FACED) and a low-noise single-cavity dual-comb laser, we achieve scan-less 3D imaging with nanometer precision and a 3D distance-imaging rate of 330 Hz, restricted only by the repetition rate difference of the dual-comb laser. Specifically, the FACED unit linearly arranges the laser beam into an array. A grating subsequently disperses this array transversely into lines, facilitating ultrafast spectroscopic applications that are 1-2 orders of magnitude quicker than traditional dual-comb methods. This spatiotemporal encoding also eases the stringent conditions on various dual-comb laser parameters, such as repetition rates, coherence, and stability. Through carefully designed experiments, we demonstrate that our scan-less system can measure 3D profiles of microfabricated structures at a rate of 7 million pixels per second. Our method significantly enhances measurement speed while maintaining high precision, using a compact light source. This advancement has the potential for broad applications, including phase imaging, surface topography, distance ranging, and spectroscopy.

4.
Biotechnol Bioeng ; 2024 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-38778433

RESUMO

Kluyveromyces marxianus, a thermotolerant, fast-growing, Crabtree-negative yeast, is a promising chassis for the manufacture of various bioproducts. Although several genome editing tools are available for this yeast, these tools still require refinement to enable more convenient and efficient genetic modification. In this study, we engineered the K. marxianus NBRC 104275 strain by impairing the nonhomologous end joining and enhancing the homologous recombination machinery, which resulted in improved homology-directed repair effective on homology arms of up to 40 bp in length. Additionally, we simplified the CRISPR-Cas9 editing system by constructing a strain for integrative expression of Cas9 nuclease and plasmids bearing different selection markers for gRNA expression, thereby facilitating iterative genome editing without the need for plasmid curing. We demonstrated that tRNA was more effective than the hammerhead ribozyme for processing gRNA primary transcripts, and readily assembled tRNA-gRNA arrays were used for multiplexed editing of at least four targets. This editing tool was further employed for simultaneous scarless in vivo assembly of a 12-kb cassette from three fragments and marker-free integration for expressing a fusion variant of fatty acid synthase, as well as the integration of genes for starch hydrolysis. Together, the genome editing tool developed in this study makes K. marxianus more amenable to genetic modification and will facilitate more extensive engineering of this nonconventional yeast for chemical production.

5.
Biochem Genet ; 2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38847869

RESUMO

Breast cancer is a global disease and a cause of cancer-related deaths in women. Long non-coding RNAs (lncRNAs) perform important functions in biological processes. The aim of this study was to verify the functions and regulatory mechanisms of linc01152 in breast cancer. Relative expression of linc01152 was measured using RT-PCR. siRNAs targeting linc01152 were designed to inhibit its expression. Cell viability, cell invasion, and migration capacities were determined using CCK-8 and Transwell assays. Downstream targets, miRNAs, and mRNAs were predicted and validated using luciferase reporter assay. The expression of linc01152 in breast cancer cells was higher than that in normal breast cells, with BT474 and MDA-MB-468 cell lines presenting the highest expression levels of linc01152. The inhibition of linc01152 expression led to lower cell viability and attenuated cell migration and invasion. The regulatory network of linc01152-miR-320a-MTDH was validated using luciferase reporter assay. The inhibition of miR-320a expression reversed the effect of si-linc01152 on cell viability, migration, and invasion. Taken together, the linc01152-miR-320a-MTDH regulatory network is correlated with the pathogenesis of breast cancer.

6.
J Am Chem Soc ; 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36753512

RESUMO

Alkene functionalization with a single-atom catalyst (SAC) which merges homogeneous and heterogeneous catalysis is a fascinating route to obtain high-value-added molecules. However, C-N bond formation of alkene with SAC is still unexplored. Herein, a bimetal-organic framework-derived Co-N/C catalyst with an atomically dispersed cobalt center is reported to show good activity of chemoselective aziridination/oxyamination reactions from alkene and hydroxylamine, and late-stage functionalization of complex alkenes and diversified synthetic transformations of the aziridine product further expand the utility of this method. Moreover, this system proceeds without external oxidants and exhibits mild, atom-economic, and recyclable characters. Detailed spectroscopic characterizations and mechanistic studies revealed the structure of the catalytic center and possible intermediates involved in the mechanism cycle.

7.
Small ; 19(31): e2205234, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36310124

RESUMO

Urea is a typical contaminant present in wastewater which may cause severe environmental problems. Electrochemical catalytic oxidation of urea has emerged as an efficient approach to solve this problem. Nevertheless, the current nickel-based catalysts (e.g., nickel hydroxide/sulfides) feature a high metal content. It not only lowers the utilization efficiency of nickel but also causes secondary pollution to the environment. Here, nickel-doped carbon dots (Ni-CDs) with an excellent and stable catalytic activity for the electrocatalytic urea oxidation reaction (UOR) are reported. Specifically, carbon dots (CDs) with abundant functional groups are synthesized by a one-pot hydrothermal method and then Ni-CDs with a very low metal content (1.1 at%) are prepared. The Ni2+ sites by coordination with carboxylic groups on the CDs provide excellent electrocatalytic activity and excellent durability for the UOR, as demonstrated by an anodic current density of 100 mA cm-2 at a potential of 1.38 V (vs RHE) and similar experimental results in practical application. To the best of knowledge, this is the first report of CDs-based materials applied for the UOR, which opens an important new area of applicability for CDs as well as broadens the scope of the materials for electrochemical catalysis of urea.

8.
Opt Express ; 31(22): 35529-35541, 2023 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-38017721

RESUMO

Pure-quartic soliton (PQS) fiber lasers provide a promising avenue for exploring novel soliton interaction dynamics and generating high-energy pulses. Here, we present the numerical observation of vector PQSs generation and the evolution dynamics in a mode-locked fiber laser, using the coupled Ginzburg-Landau equations. We investigate the buildup dynamics of vector PQSs in a mode-locked laser with birefringent fibers, passing through three stages: energy amplification, energy pulsation owing to the cross-phase modulation (XPM) effect, and finally stabilization. Depending on the strength of the cavity-birefringence, the evolution of PQSs in non-polarization-maintaining fibers reveals that both the elliptical-polarization vector PQSs and near-linear-polarization vector PQSs can be formed by the energy conservation and balance between the two orthogonal directions. Additionally, we observe the transition process from vector PQSs to scalar PQSs with higher cavity-birefringence, resulting from the failure compensation of the walk-off via the soliton trapping effect between the two orthogonal components. These results provide valuable insights into the ultrafast transient process of vector solitons and enhance the understanding of PQS generation in fiber lasers.

9.
Opt Express ; 31(10): 15864-15875, 2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37157677

RESUMO

Chromatic confocal sensor-based on-machine measurement is effective for identifying and compensating for form errors of the ultra-precisely machined components. In this study, an on-machine measurement system was developed for an ultra-precision diamond turning machine to generate microstructured optical surfaces, for which the sensor probe adopts a uniform spiral scanning motion. To avoid the tedious spiral center alignment, a self-alignment method was proposed without additional equipment or artefact, which identified the deviation of the optical axis to the spindle axis by matching the measured surface points and the designed surface. The feasibility of the proposed method was demonstrated by numerical simulation with full consideration of noises and system dynamics. Practically, taking a typical microstructured surface as an example, the on-machine measured points were reconstructed after calibrating the alignment deviation, which was then verified by off-machine white light interferometry measurement. Avoiding tedious operations and special artefacts may significantly simplify the on-machine measurement process, thereby greatly improving the efficiency and flexibility for the measurement.

10.
Opt Express ; 31(20): 32373-32382, 2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37859042

RESUMO

Synchronised ultrafast soliton lasers have attracted great research interest in recent decades. However, there is a lack of comprehensive understanding regarding the buildup mechanism of synchronised pulses. Here, we report a dynamic analysis of independent and synchronised solitons buildup mechanisms in synchronised ultrafast soliton lasers. The laser comprises an erbium-doped fibre cavity and a thulium-doped fibre cavity bridged with a common arm. Pulses operating at two different wavelengths formed in the cavities are synchronised by cross-phase modulation-induced soliton correlation in the common fibre arm. We find that the whole buildup process of the thulium-doped fibre laser successively undergoes five different stages: continuous wave, relaxation oscillation, quasi-mode-locking, continuous wave mode-locking and synchronised mode-locking. It is found that the starting time of the synchronised solitons is mainly determined by the meeting time of dual-color solitons. Our results will further deepen the understanding of dual-color synchronised lasers and enrich the study of complex nonlinear system dynamics.

11.
Mediators Inflamm ; 2023: 9077787, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37197571

RESUMO

Background: Neonatal sepsis is an extremely dangerous and fatal disease among neonates, and its timely diagnosis is critical to treatment. This research is aimed at evaluating the clinical significance of the lymphocyte-to-C-reactive protein ratio (LCR) as an early sepsis indicator in neonates with suspected sepsis. Methods: Between January 2016 and December 2021, 1269 neonates suspected of developing sepsis were included in this research. Among them, sepsis was diagnosed in 819 neonates, with 448 severe cases, as per the International Pediatric Sepsis Consensus. Data related to clinical and laboratory tests were obtained via electronic medical records. LCR was calculated as total lymphocyte (109 cells/L)/C-reactive protein (mg/L). Multivariate logistic regression analysis was employed to evaluate the effectiveness of LCR as an independent indicator for determining sepsis in susceptible sepsis neonates. Receiver operating characteristic (ROC) curve analysis was conducted for investigating the diagnostic significance of LCR in sepsis. When suitable, the statistical tool SPSS 24.0 was used for statistical analyses. Results: LCR decreased significantly in the control, mild, and severe sepsis groups. Further analyses exhibited that there was a substantially greater incidence of sepsis in neonates in the low-LCR group (LCR ≤ 3.94) as opposed to the higher LCR group (LCR > 3.94) (77.6% vs. 51.4%, p < 0.001). Correlation analysis indicated a substantial negative association of LCR with procalcitonin (r = -0.519, p < 0.001) and hospital stay duration (r = -0.258, p < 0.001). Multiple logistic regression analysis depicted LCR as an independent indicator for identifying sepsis and severe cases of this disease. ROC curve analysis indicated the optimal cutoff value of LCR in identifying sepsis to be 2.10, with 88% sensitivity and 55% specificity. Conclusions: LCR has proven to be a potentially strong biomarker capable of identifying sepsis in a timely manner in neonates suspected to have the disease.


Assuntos
Proteína C-Reativa , Sepse , Humanos , Recém-Nascido , Biomarcadores , Proteína C-Reativa/metabolismo , Calcitonina , Estudos Retrospectivos , Curva ROC , Sepse/diagnóstico
12.
Proc Natl Acad Sci U S A ; 117(37): 22974-22983, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32873649

RESUMO

Medium-chain fatty alcohols (MCFOHs, C6 to C12) are potential substitutes for fossil fuels, such as diesel and jet fuels, and have wide applications in various manufacturing processes. While today MCFOHs are mainly sourced from petrochemicals or plant oils, microbial biosynthesis represents a scalable, reliable, and sustainable alternative. Here, we aim to establish a Saccharomyces cerevisiae platform capable of selectively producing MCFOHs. This was enabled by tailoring the properties of a bacterial carboxylic acid reductase from Mycobacterium marinum (MmCAR). Extensive protein engineering, including directed evolution, structure-guided semirational design, and rational design, was implemented. MmCAR variants with enhanced activity were identified using a growth-coupled high-throughput screening assay relying on the detoxification of the enzyme's substrate, medium-chain fatty acids (MCFAs). Detailed characterization demonstrated that both the specificity and catalytic activity of MmCAR was successfully improved and a yeast strain harboring the best MmCAR variant generated 2.8-fold more MCFOHs than the strain expressing the unmodified enzyme. Through deletion of the native MCFA exporter gene TPO1, MCFOH production was further improved, resulting in a titer of 252 mg/L for the final strain, which represents a significant improvement in MCFOH production in minimal medium by S. cerevisiae.


Assuntos
Álcoois Graxos/metabolismo , Oxirredutases/metabolismo , Antiporters/metabolismo , Biocombustíveis , Ácidos Graxos/metabolismo , Engenharia Metabólica/métodos , Proteínas de Transporte de Cátions Orgânicos/genética , Oxirredutases/fisiologia , Engenharia de Proteínas/métodos , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo
13.
Nano Lett ; 22(23): 9396-9404, 2022 12 14.
Artigo em Inglês | MEDLINE | ID: mdl-36410737

RESUMO

Animals create high-performance fibers at natural ambient conditions via a unique spinning process. In contrast, the spinning technologies developed by human beings are usually clumsy and require sophisticated skills. Here, inspired by adhesion-based silkworm spinning, we report a microadhesion guided (MAG) spinning technology for instant and on-demand fabrication of micro/nanofibers. Enabled by the adhesion between the spinning fluids and the microneedles, the MAG spinning can generate micro/nanofibers with programmable morphology. By further mimicking the head movement of the silkworm spinning, the MAG technology is extended with three different modes: straight, vibratory, and twisted spinning, which generate oriented fibers, hierarchical cross-linked fibers, and all-in-one fibers, respectively. Due to the prevalence of microadhesion and its unprecedented flexibility in operation, equipment-free MAG spinning is finally realized for instant fiber fabrication by only polymeric foams. Finally, the MAG spinning is demonstrated as a promising instant technology for emergent applications, such as wound dressing.


Assuntos
Bombyx , Nanofibras , Animais , Humanos , Biomimética , Polímeros
14.
Molecules ; 28(2)2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36677598

RESUMO

Carbon materials with pseudocapacitive performance have attracted emerging interest in the energy storage and conversion field. Reduced graphene oxide (r-GO) with superior conductivity and electrochemical stability has been extensively investigated as an efficient capacitive electrode material. In this study, three-dimensional carbon dots (CDs)@r-GO hydrogel electrode was successfully in situ prepared by the one-pot method, where the CDs play a critical role in serving as both reduction agent and electrochemical active sites. With prolonged reaction time, the oxygen content of the CDs@r-GO nanocomposite material could be effectively reduced to ensure better electric conductivity, and the nitrogen content, which provides pseudocapacitance, was gradually increased. The representative two pairs of fast and reversible current peaks appeared in cyclic voltammetry curves, with around three times higher specific capacitance of CDs@r-GO hydrogel electrode (290 F g-1 at the current density of 1 A g-1 in 1 M H2SO4 electrolyte). This simple and mild approach is promising and it is believed it will shed more light on the preparation of high-efficiency and high-performance energy storage materials based on functional reductive CDs.

15.
Anal Chem ; 94(27): 9801-9810, 2022 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-35766488

RESUMO

Charge (ion and electron)-transfer reactions at a liquid/liquid interface are critical processes in many important biological and chemical systems. An ion-transfer (IT) process is usually very fast, making it difficult to accurately measure its kinetic parameters. Nano-liquid/liquid interfaces supported at nanopipettes are advantageous approaches to study the kinetics of such ultrafast IT processes due to their high mass transport rate. However, correct measurements of IT kinetic parameters at nanointerfaces supported at nanopipettes are inhibited by a lack of knowledge of the nanometer-sized interface geometry, influence of the electric double layer, wall charge polarity, etc. Herein, we propose a new electrochemical characterization equation for nanopipettes and make a suggestion on the shape of a nano-water/1,2-dichloroethane (nano-W/DCE) interface based on the characterization and calculation results. A theoretical model based on the Poisson-Nernst-Planck equation was applied to systematically study how the electric double layer influences the IT process of cations (TMA+, TEA+, TPrA+, ACh+) and anions (ClO4-, SCN-, PF6-, BF4-) at the nano-W/DCE interface. The relationships between the wall charge conditions and distribution of concentration and potential inside the nanopipette revealed that the measured standard rate constant (k0) was enhanced when the polarity of the ionic species was opposite to the pipette wall charge and reduced when the same. This work lays the right foundation to obtain the kinetics at the nano-liquid/liquid interfaces.


Assuntos
Dicloretos de Etileno , Ânions , Cátions , Dicloretos de Etileno/química , Cinética , Eletricidade Estática
16.
Opt Express ; 30(15): 27249-27258, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-36236899

RESUMO

We propose a flat retroreflector that can efficiently reflect the electromagnetic waves back along its incident direction in a wide continuous range of angles. This retroreflector consists of a quadratic metalens and a flat metallic reflector at the focal plane of the former. The quadratic metalens is a dielectric pillar array encoded with a quadratic phase profile and it is embedded in the top side of the substrate. The flat reflector is on the bottom side of the substrate. The designed retroreflector has a diameter of 40 mm, a thickness of 15 mm, and a working frequency of 77 GHz. Through meta-units optimization, a retroreflection efficiency of 38.51% at ± 60° incidence and an average retroreflection efficiency of 46.39% for the incident angles from 0° to 60° can be numerically demonstrated. This flat retroreflector is easy for integration, which is promising for potential applications in the miniature wireless communication systems.

17.
Crit Rev Food Sci Nutr ; 62(14): 3705-3722, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35348019

RESUMO

The membrane can not only be used as food packaging, but also for the separation, fractionation and recovery of food ingredients. Graphene oxide (GO) sheets are a two-dimensional (2 D) material with a unique structure that exhibit excellent mechanical properties, biocompatibility, and flexibility. The corporation of polymer matrix membrane with GO can significantly improve the permeability, selectivity, and antibacterial activity. In this review, the chemical structures of GO, GO membranes and GO/polymer composite membranes are introduced, the permeation mechanisms of molecules through the membranes are discussed and key factors affecting the permeability are presented in detail. In addition, recent applications in the food industry for filtration, bioreactions and active food packaging are analyzed, and limitations and future trends of GO membranes development are also highlighted. GO/polymer composite membranes exhibit excellent permeability, selectivity and strong barrier properties against bacterial and gas permeation. However, current food material filtration and packaging applications of GO/polymer composite membranes are still in the laboratory stage. Future work can focus on the development of large scale uniformly sized GO production, the homogeneous distribution and tight combination of GO in polymer matrixes, the sensing function of GO in packaging, and the verification method of GO toxicology.


Assuntos
Grafite , Polímeros , Embalagem de Alimentos , Grafite/química , Membranas Artificiais
18.
Skeletal Radiol ; 51(5): 1017-1026, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-34599674

RESUMO

OBJECTIVES: The integrity of endplate is important for maintaining the health of adjacent disc and trabeculae. Yet, pathological impacts of traumatic vertebra and endplate fractures were less studied using clinical approaches. This study aims to investigate their effects on the development of adjacent disc degeneration, segmental kyphosis, Modic changes (MCs), and high-intensity zones (HIZs). MATERIALS AND METHODS: Magnetic resonance (MR) images of patients with acute traumatic vertebral compression fractures (T11-L5) were studied. On MR images, endplate fractures were evaluated as present or absent. Disc signal, height, bulging area, sagittal Cobb angle, MCs, and HIZs were measured on baseline and follow-up MR images to study the changes of the disc in relation to vertebra fractures and endplate fractures. RESULTS: Ninety-seven patients were followed up for 15.4 ± 14.0 months. There were 123 fractured vertebrae, including 79 (64.2%) with endplate fractures and 44 (35.8%) without. Both the adjacent and control discs decreased in signal and height over time (p < 0.001), and the disc adjacent to vertebral fractures had greater signal and height loss than the control disc (p < 0.05). In the presence of endplate fractures, the adjacent discs had greater signal decrease in follow-up (p < 0.05), as compared to those without endplate fractures. Sagittal Cobb angle significantly increased in segments with endplate fractures (p < 0.05). Vertebra fractures were associated with new occurrence of MCs in the fractured vertebra (p < 0.001) but not HIZs in the adjacent disc. CONCLUSIONS: Traumatic vertebral fractures were associated with accelerated adjacent disc degeneration, which appears to be further promoted by concomitant endplate fractures. Endplate fractures were associated with progression of segmental kyphosis.


Assuntos
Fraturas por Compressão , Degeneração do Disco Intervertebral , Disco Intervertebral , Fraturas da Coluna Vertebral , Seguimentos , Fraturas por Compressão/diagnóstico por imagem , Humanos , Disco Intervertebral/patologia , Degeneração do Disco Intervertebral/diagnóstico por imagem , Degeneração do Disco Intervertebral/patologia , Vértebras Lombares/patologia , Imageamento por Ressonância Magnética/métodos , Fraturas da Coluna Vertebral/diagnóstico por imagem
19.
Mikrochim Acta ; 189(4): 138, 2022 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-35262833

RESUMO

On-line monitoring of the dopamine (DA)-based molecular imprinting processes over Fe3O4@SiO2-NH2 nanoparticles (SiMNPs) is reported by using a real-time quantitative PCR machine. Taking advantages of the efficient fluorescence quenching capability of polydopamine (PDA) and its high binding affinity to rhodamine B (RhB), we performed molecular imprinting against different proteins with free dopamine as the functional monomer and RhB as a fluorescent indicator. Along with the template molecules, the fluorescent indicators were continuously encapsulated into the PDA layer formed on the surface of the SiMNPs, resulting in immediate quenching of the fluorescence, which can be conveniently monitored in real time. As proteins showed sequence-dependent influences on the oxidation of dopamine and subsequent self-assembly on the surface of the SiMNPs, the observed fluorescence signals clearly indicated the polymerization progress in the presence of the template proteins, allowing precise control of the reaction time for different templates at a given initial concentration. The optimum end point of the reaction was found to be when 90 ± 3% of the templates had been encapsulated into the polymer, which offered the highest imprinting factor and selectivity. We applied the approach to prepare a primary PDA-based surface imprinted polymer for a multifunctional protein apurinic/apyrimidinic endonuclease/redox effector factor 1 (APE1). After further introduction of 3-hydroxyphenylboronic acid to the interfaces between APE1 and PDA, the resultant molecularly imprinted polymers (MIP-II) enabled quantitative isolation APE1 from cell lysate samples. The developed approach will be useful for the quantitative preparation of PDA-based MIPs for precious template proteins with limited input quantity. It is also applicable for further study on the effects of different proteins or peptides on the PDA formation reactions.


Assuntos
Impressão Molecular , Dopamina/química , Impressão Molecular/métodos , Polimerização , Polímeros/química , Proteínas , Dióxido de Silício/química
20.
BMC Med Educ ; 22(1): 699, 2022 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-36192723

RESUMO

BACKGROUND: There is a global increase in the prevalence of autism spectrum disorder (ASD). Early identification of ASD in children and intervention are key aspects in the management of ASD. However, early identification is partly dependent on knowledge on ASD among pediatricians. This study analyzed the extent of ASD knowledge and its underlying factors among pediatric residents in eastern China, to provide a reference for medical education reforms. METHODS: The study employed the Knowledge about Childhood Autism among Health Workers questionnaire. A total of 138 pediatric residents participated in the survey. Descriptive statistics were used to describe demographic characteristics and the four domains of the questionnaire. Univariate analysis was employed to assess impacts of the demographic characteristics on the questionnaire scores. On the other hand, multivariate regression analysis was used to analyze the correlation between the participants' demographic characteristics and the questionnaire scores. RESULTS: The average ASD cognitive score of 138 respondents was 13.38 ± 4.48. The ASD cognitive scores in female pediatric residents were higher compared to that in males (p < 0.05). Residents who had obtained professional doctor qualification certificate were more than those without professional doctor qualification certificate (p < 0.05). The ASD knowledge in the group which did not have rotation in both departments was lower than in the group which had rotation in both departments (p < 0.05) as well as the group that had rotation in developmental and behavioral pediatrics department only (p < 0.05). Our multivariate linear regression model demonstrated significant statistical differences (p < 0.05), and showed that gender and systematic exposure to ASD knowledge had significant effects on cognitive scores (p < 0.05). CONCLUSION: Most participants had relatively low levels of awareness and knowledge about ASD, especially on ASD comorbidities and age of onset. Women, systematic learning of ASD knowledge in medical school, successful passing of the physician examination, and rotation in the developmental and behavioral pediatrics (DBP) department significantly influence the levels of ASD awareness and knowledge. It is, therefore, important to strengthen ASD education in medical students at the university level and make rotation in the DBP department a requisite for pediatric trainees.


Assuntos
Transtorno do Espectro Autista , Conhecimentos, Atitudes e Prática em Saúde , Estudantes de Medicina , Transtorno do Espectro Autista/diagnóstico , Transtorno do Espectro Autista/epidemiologia , Transtorno do Espectro Autista/psicologia , Criança , China/epidemiologia , Estudos Transversais , Feminino , Humanos , Masculino , Inquéritos e Questionários
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa