Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 73
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Bioresour Technol ; 344(Pt B): 126237, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34756978

RESUMO

High solid anaerobic digestion (HSAD)'s complex rheological behavior exhibits short-circuiting and dead zone. Mixing optimization is potential to enhance HSAD hydrodynamics. Besides, scale-up effect is quite essential for HSAD's applications, but remains rarely studied yet. Effect of impeller with different width on the correlation of "mixing-fluidity-energy" at different rotating speeds was first investigated at pilot-scale in present work. Then, scale-up effect based on rotating speed and a generalized Reynolds number was revealed from the aspects of fluidity and energy consumption. Results show that impeller width of 100 mm (10 rpm), 200 mm and 300 mm (5 and 10 rpm) are preferred for hydrodynamics and energy economics. Furthermore, Re similarity has better referential significance for the scale-up. In this study, new insight is gained into the correlation of "mixing-fluidity-energy" within a pilot-scale digester. Scale-up effect based Re similarity could potentially offer guidance for HSAD's application in the practical engineering.


Assuntos
Reatores Biológicos , Hidrodinâmica , Anaerobiose , Reologia
2.
Nat Commun ; 12(1): 7196, 2021 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-34893613

RESUMO

Interfacial moiré superlattices in van der Waals vertical assemblies effectively reconstruct the crystal symmetry, leading to opportunities for investigating exotic quantum states. Notably, a two-dimensional nanosheet has top and bottom open surfaces, allowing the specific case of doubly aligned super-moiré lattice to serve as a toy model for studying the tunable lattice symmetry and the complexity of related electronic structures. Here, we show that by doubly aligning a graphene monolayer to both top and bottom encapsulating hexagonal boron nitride (h-BN), multiple conductivity minima are observed away from the main Dirac point, which are sensitively tunable with respect to the small twist angles. Moreover, our experimental evidences together with theoretical calculations suggest correlated insulating states at integer fillings of -5, -6, -7 electrons per moiré unit cell, possibly due to inter-valley coherence. Our results provide a way to construct intriguing correlations in 2D electronic systems in the weak interaction regime.

3.
ACS Appl Mater Interfaces ; 13(51): 61544-61554, 2021 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-34910468

RESUMO

Polarization-sensitive photodetection is highly appealing considering its great important applications. However, the inherent in-plane symmetry of a material and the single structure of a detector hinder the further development of polarization detectors with high anisotropic ratios. Herein, we design a p-WSe2/TaIrTe4/n-MoS2 (p-Ta-n) heterojunction. As a type-II Weyl semimetal, TaIrTe4 with an orthorhombic structure has strong in-plane asymmetry, which is confirmed by angle-resolved polarized Raman spectroscopy and second-harmonic generation. Due to the specific structure of the p-Ta-n junction with two vertical built-in electric fields, the device obtains a broadband self-powered photodetection ranging from visible (405 nm) to telecommunication wavelength (1550 nm) regions. Further, an optimized device containing 50-70 nm-thick layered TaIrTe4 has been realized. What is more, high-resolution imaging of "T" based on the device with clear borders illustrates excellent stability of the device. Significantly, the photocurrent anisotropic ratio of the p-Ta-n detector can reach 9.1 under 635 nm light, which is more than eight times that of the best known TaIrTe4-based photodetector reported before. This p-Ta-n junction containing a type-II Weyl fermion semimetal can provide an effective approach toward highly polarization-sensitive and high-performance integrated broadband photodetectors.

4.
Front Microbiol ; 12: 744007, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34777291

RESUMO

The present study sought to isolate a novel exopolysaccharide (EPS-F2) from Enterococcus sp. F2 through ethanol precipitation, anion-exchange, and gel-filtration chromatography and characterize the physicochemical properties by spectral techniques. EPS-F2 was identified as a neutral homo-exopolysaccharide composed of only glucose with a high molecular weight of 1.108 × 108 g/mol. It contained →6)-α-D-Glcp-(1→ linkage in the main chain and →3, 6)-α-D-Glcp-(1→ branch chain). Moreover, EPS-F2 possessed excellent thermal stability (266.6°C), water holding capacity (882.5%), oil holding capacity (1867.76%), and emulsifying activity against various edible oils. The steady shear experiments exhibited stable pseudo plasticity under various conditions (concentrations, temperatures, and pHs). The dynamic oscillatory measurements revealed that EPS-F2 showed a liquid-like behavior at a low concentration (2.5%), while a solid-like behavior at high concentrations (3.0 and 3.5%). Overall, these results suggest that EPS-F2 could be a potential alternative source of functional additives and ingredients and be applied in food industries.

5.
Ophthalmology ; 2021 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-34619247

RESUMO

PURPOSE: To develop and evaluate the performance of a 3-dimensional (3D) deep-learning-based automated digital gonioscopy system (DGS) in detecting 2 major characteristics in eyes with suspected primary angle-closure glaucoma (PACG): (1) narrow iridocorneal angles (static gonioscopy, Task I) and (2) peripheral anterior synechiae (PAS) (dynamic gonioscopy, Task II) on OCT scans. DESIGN: International, cross-sectional, multicenter study. PARTICIPANTS: A total of 1.112 million images of 8694 volume scans (2294 patients) from 3 centers were included in this study (Task I, training/internal validation/external testing: 4515, 1101, and 2222 volume scans, respectively; Task II, training/internal validation/external testing: 378, 376, and 102 volume scans, respectively). METHODS: For Task I, a narrow angle was defined as an eye in which the posterior pigmented trabecular meshwork was not visible in more than 180° without indentation in the primary position captured in the dark room from the scans. For Task II, PAS was defined as the adhesion of the iris to the trabecular meshwork. The diagnostic performance of the 3D DGS was evaluated in both tasks with gonioscopic records as reference. MAIN OUTCOME MEASURES: The area under the curve (AUC), sensitivity, and specificity of the 3D DGS were calculated. RESULTS: In Task I, 29.4% of patients had a narrow angle. The AUC, sensitivity, and specificity of 3D DGS on the external testing datasets were 0.943 (0.933-0.953), 0.867 (0.838-0.895), and 0.878 (0.859-0.896), respectively. For Task II, 13.8% of patients had PAS. The AUC, sensitivity, and specificity of 3D DGS were 0.902 (0.818-0.985), 0.900 (0.714-1.000), and 0.890 (0.841-0.938), respectively, on the external testing set at quadrant level following normal clinical practice; and 0.885 (0.836-0.933), 0.912 (0.816-1.000), and 0.700 (0.660-0.741), respectively, on the external testing set at clock-hour level. CONCLUSIONS: The 3D DGS is effective in detecting eyes with suspected PACG. It has the potential to be used widely in the primary eye care community for screening of subjects at high risk of developing PACG.

6.
Clin Sci (Lond) ; 135(20): 2357-2376, 2021 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-34661658

RESUMO

Ophthalmology has been one of the early adopters of artificial intelligence (AI) within the medical field. Deep learning (DL), in particular, has garnered significant attention due to the availability of large amounts of data and digitized ocular images. Currently, AI in Ophthalmology is mainly focused on improving disease classification and supporting decision-making when treating ophthalmic diseases such as diabetic retinopathy, age-related macular degeneration (AMD), glaucoma and retinopathy of prematurity (ROP). However, most of the DL systems (DLSs) developed thus far remain in the research stage and only a handful are able to achieve clinical translation. This phenomenon is due to a combination of factors including concerns over security and privacy, poor generalizability, trust and explainability issues, unfavorable end-user perceptions and uncertain economic value. Overcoming this challenge would require a combination approach. Firstly, emerging techniques such as federated learning (FL), generative adversarial networks (GANs), autonomous AI and blockchain will be playing an increasingly critical role to enhance privacy, collaboration and DLS performance. Next, compliance to reporting and regulatory guidelines, such as CONSORT-AI and STARD-AI, will be required to in order to improve transparency, minimize abuse and ensure reproducibility. Thirdly, frameworks will be required to obtain patient consent, perform ethical assessment and evaluate end-user perception. Lastly, proper health economic assessment (HEA) must be performed to provide financial visibility during the early phases of DLS development. This is necessary to manage resources prudently and guide the development of DLS.

7.
Cell ; 184(22): 5559-5576.e19, 2021 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-34678143

RESUMO

Glucose consumption is generally increased in tumor cells to support tumor growth. Interestingly, we report that glycogen accumulation is a key initiating oncogenic event during liver malignant transformation. We found that glucose-6-phosphatase (G6PC) catalyzing the last step of glycogenolysis is frequently downregulated to augment glucose storage in pre-malignant cells. Accumulated glycogen undergoes liquid-liquid phase separation, which results in the assembly of the Laforin-Mst1/2 complex and consequently sequesters Hippo kinases Mst1/2 in glycogen liquid droplets to relieve their inhibition on Yap. Moreover, G6PC or another glycogenolysis enzyme-liver glycogen phosphorylase (PYGL) deficiency in both human and mice results in glycogen storage disease along with liver enlargement and tumorigenesis in a Yap-dependent manner. Consistently, elimination of glycogen accumulation abrogates liver growth and cancer incidence, whereas increasing glycogen storage accelerates tumorigenesis. Thus, we concluded that cancer-initiating cells adapt a glycogen storing mode, which blocks Hippo signaling through glycogen phase separation to augment tumor incidence.

8.
Sensors (Basel) ; 21(17)2021 Sep 02.
Artigo em Inglês | MEDLINE | ID: mdl-34502800

RESUMO

Real-time 3D reconstruction is one of the current popular research directions of computer vision, and it has become the core technology in the fields of virtual reality, industrialized automatic systems, and mobile robot path planning. Currently, there are three main problems in the real-time 3D reconstruction field. Firstly, it is expensive. It requires more varied sensors, so it is less convenient. Secondly, the reconstruction speed is slow, and the 3D model cannot be established accurately in real time. Thirdly, the reconstruction error is large, which cannot meet the requirements of scenes with accuracy. For this reason, we propose a real-time 3D reconstruction method based on monocular vision in this paper. Firstly, a single RGB-D camera is used to collect visual information in real time, and the YOLACT++ network is used to identify and segment the visual information to extract part of the important visual information. Secondly, we combine the three stages of depth recovery, depth optimization, and deep fusion to propose a three-dimensional position estimation method based on deep learning for joint coding of visual information. It can reduce the depth error caused by the depth measurement process, and the accurate 3D point values of the segmented image can be obtained directly. Finally, we propose a method based on the limited outlier adjustment of the cluster center distance to optimize the three-dimensional point values obtained above. It improves the real-time reconstruction accuracy and obtains the three-dimensional model of the object in real time. Experimental results show that this method only needs a single RGB-D camera, which is not only low cost and convenient to use, but also significantly improves the speed and accuracy of 3D reconstruction.


Assuntos
Imageamento Tridimensional , Realidade Virtual , Algoritmos , Visão Monocular
9.
Mol Med Rep ; 24(5)2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34498704

RESUMO

Sepsis is a severe disease, with high mortality. Permanent organ damage caused by sepsis reduces the quality of life of surviving patients. The liver is an easily damaged organ in sepsis and sepsis­associated liver injury foretells a poor prognosis. Unfortunately, there are no effective treatments or drugs to solve this problem. Therefore, strategies or novel drugs are urgently required to protect against liver dysfunction in sepsis. In the present study, lipopolysaccharide (LPS) was used to establish a model of liver injury in vitro. The data demonstrated that pretreatment of L02 human normal hepatocytes with paeonol (PAE) alleviated LPS­induced cell injury and decreased the levels of alanine aminotransferase and aspartate transaminase, indicating a protective effect of PAE. Further experiments demonstrated that PAE increased LPS­decreased L02 cell viability, the levels of superoxide dismutase and Bcl­2 expression. PAE decreased LPS­increased cell apoptosis, intracellular reactive oxygen species and the expression levels of Bax and cleaved­caspase­3. PAE decreased LPS­promoted mitochondrial depolarization and nuclear translocation of NF­κB. In conclusion, PAE alleviated LPS­induced liver injury via alteration of mitochondrial function and NF­κB translocation. Therefore, PAE has potential for the treatment of sepsis.

10.
SN Appl Sci ; 3(8): 754, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34337325

RESUMO

The promulgation and implementation of the national and Beijing municipal standards for air pollutants emitted from crematoriums has effectively alleviated the problem of "black smoke" in crematoriums, but noticeable odor in crematoriums remains. We determined the level of odor emissions in crematoriums by monitoring the odor concentrations of cremators, incinerators, and cremation workshops in five crematoriums in Beijing. Subsequently, we analyzed the major contributing factors to the odor level and proposed control measures. A high odor concentration in crematoriums was observed; two different mechanisms were proposed to explain this finding. First, poor ventilation conditions in workshops and inadequate airtightness of equipment resulted in dimensionless concentrations of unorganized odor emissions in the workshops ranging from 97 to 732, with an average of 504, which is much higher than the standard level of 20. Second, the postprocessing facilities used in cremation sites produce poor odor removal, which, coupled with fuel usage and unregulated operations, led to high concentrations of organized odor emissions ranging from 231 to 1303 (910 on average) for cremators and incinerators. The odor emissions of cremators and incinerators meet the Integrated Emission Standards of Air Pollutants (DB11-501-2017), which are suitable for industries containing industrial kilns but not for crematoriums. The odor emissions in crematoriums are lower than those emitted from industries, such as fiber manufacturing and activated carbon processing. However, the unique geographical locations of crematoriums, high population density, and high exposure risk to local residents necessitate strengthening the management and control of odor emissions from crematoriums. To further address the problem of odor emissions from crematoriums in Beijing, further clarification and tightening of industry standards for the concentration limits of organized and unorganized odor emissions is recommended. Crematoriums will thus be prompted to increase odor control in workshops and adopt and improve deodorization facilities, including the installation and application of treatment facilities, such as adsorption and biological control.

11.
J Phys Chem Lett ; 12(28): 6492-6498, 2021 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-34240885

RESUMO

Chiral hybrid organic-inorganic perovskites (chiral HOIPs) present potential spintronic and spin-optoelectronic applications due to their unique spin-related properties. However, the spin physics in chiral HOIPs has rarely been explored by theoretical studies. Here, with first-principles calculations, we investigate the spin characteristics of the Pb-I based chiral HOIPs and propose an effective approach to significantly increase the spin splitting with a halogen-substituted chiral molecule. Compared to the value of 13 meV without halogen substitution, the spin splitting energy can be significantly enhanced to 73, 90, and 105 meV with F, Cl, and Br substitution, respectively. A k·p model Hamiltonian based on a symmetry argument reveals that the halogen substitution enhances the local electric field, inducing distortion of the PbI6 octahedron. Further calculation demonstrates that halogen substitution can strongly modify the electrostatic potential surface of the chiral molecules. This work presents an effective molecular engineering approach to modulate spin splitting of chiral HOIPs, shedding light on the design of spintronic materials.

12.
Prep Biochem Biotechnol ; : 1-9, 2021 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-34236935

RESUMO

This study aimed to investigate the optimal fermentation condition, purification and rheological properties of extracellular polymers produced by Bacillus subtilis 1006-3. An optimum temperature of 30.2 °C, inoculation amount of 6.1%, and pH of 8.2 were determined via Response Surface Methodology. The result of amino acid analysis and gel electrophoresis indicated that the obtained polymer contained only glutamic acid, with a wide molecular weight range. This polymer was finally determined as γ-PGA by infrared spectroscopy. The γ-PGA solution displayed a behavior of pseudoplastic non-Newtonian fluid with shear thinning properties, which can be described by the Ostward-de Waele power law model. The apparent viscosity of γ-PGA solution increased with the increase in its concentration from 1% to 10%. The deviation in pH from neutral value, and the addition of NaCl or MgCl2 can reduce the apparent viscosity of γ-PGA solution, and it was more sensitive to Mg2+ than to Na+ addition. At the concentration of 4, 6, and 8%, γ-PGA solution showed predominantly viscous response in the range of 0.1-100 rad/s angular frequency (G″>G'). These results indicated the potential application of the γ-PGA as a thickening agent.

13.
Food Chem ; 365: 130496, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34237575

RESUMO

An exopolysaccharide, EPS-B108, was isolated from the fermented broth (with a yield of 11.3 g/L) of halotolerant Bacillus sp. SCU-E108 by ethanol precipitation, anion-exchange and gel-filtration chromatography, and well characterized by means of physical, chemical and spectral techniques. Data indicated that EPS-B108 was composed solely of fructose with a high molecular weight of 3.578 × 107 g/mol, and contained a ß-(2 â†’ 6)-linked d-Fruf backbone with a single ß-d-Fruf at C-1 position. An irregular saccular- or cake-like shape was observed under the enlarged view. It showed no acute oral toxicity in mice, and had good thermal stability (242 °C), solubility in water (91.3%) and oil-holding capacity (1717.0%). Steady-shear flow and dynamical viscoelasticity of aqueous EPS-B108 solutions varied with the polymer concentration, shear rate and temperature, and were described by the Power-law model. Together, these findings support the further application of EPS-B108 as an alternative source of functional food additives and ingredients.


Assuntos
Bacillus , Frutanos , Animais , Cromatografia em Gel , Camundongos , Peso Molecular , Polissacarídeos Bacterianos , Solubilidade , Água
14.
Phys Rev Lett ; 126(24): 246601, 2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34213928

RESUMO

The magnetic van der Waals crystals MnBi_{2}Te_{4}/(Bi_{2}Te_{3})_{n} have drawn significant attention due to their rich topological properties and the tunability by external magnetic field. Although the MnBi_{2}Te_{4}/(Bi_{2}Te_{3})_{n} family have been intensively studied in the past few years, their close relatives, the MnSb_{2}Te_{4}/(Sb_{2}Te_{3})_{n} family, remain much less explored. In this work, combining magnetotransport measurements, angle-resolved photoemission spectroscopy, and first principles calculations, we find that MnSb_{4}Te_{7}, the n=1 member of the MnSb_{2}Te_{4}/(Sb_{2}Te_{3})_{n} family, is a magnetic topological system with versatile topological phases that can be manipulated by both carrier doping and magnetic field. Our calculations unveil that its A-type antiferromagnetic (AFM) ground state stays in a Z_{2} AFM topological insulator phase, which can be converted to an inversion-symmetry-protected axion insulator phase when in the ferromagnetic (FM) state. Moreover, when this system in the FM phase is slightly carrier doped on either the electron or hole side, it becomes a Weyl semimetal with multiple Weyl nodes in the highest valence bands and lowest conduction bands, which are manifested by the measured notable anomalous Hall effect. Our work thus introduces a new magnetic topological material with different topological phases that are highly tunable by carrier doping or magnetic field.

15.
Food Chem ; 363: 130288, 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34120043

RESUMO

Table grape is a popular fruit worldwide. The quality of the appearance of table grapes directly affects their commercial value. Table grape bunches are usually carefully managed during production. At different developmental stages, a large number of grape berries are pruned as waste for commercial appearance, which leads to wasted resources. Ultraviolet-C (UV-C) can regulate the accumulation of secondary metabolites in fruits. In this study, metabolomic profile was combined with transcriptomic analysis technology to explore the value of UV-C in improving the utilization of waste grapes. The berries of the 'Jumeigui' grape were subjected to UV-C radiation treatment in the green-berry stage, veraison stage, and maturation stage. The results showed that UV-C could brown grape berries and decrease their sugar content at different developmental stages. Compared with other samples, those treated with UV-C in the veraison stage had the most upregulated metabolites, while samples in the green-berry stage had the most down-regulated metabolites. UV-C promoted the accumulation of stilbenes and some flavonoids in the berries at each developmental stage (especially at the green-berry and veraison stages). Compared with other stages, UV-C treatment during the veraison stage led to the highest number of upregulated genes related to transcription factors, protein modification, indole-3-acetic acid (IAA), abscisic acid (ABA), gibberellin acid (GA), receptor kinases, and Ascorbic acid/Glutathione (Ascorb/Gluath). UV-C might promote the accumulation of phenolic components by upregulating the expression of their biosynthesis related genes. UV-C may be an effective in vitro approach for improving the application value of waste grape berries by enhancing the accumulation of the nutritious phenolic components.


Assuntos
Vitis , Ácido Abscísico , Frutas/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Transcriptoma , Vitis/genética
16.
Cell Death Dis ; 12(6): 576, 2021 06 04.
Artigo em Inglês | MEDLINE | ID: mdl-34088891

RESUMO

Cancer-secreted exosomes are critical mediators of cancer-host crosstalk. In the present study, we showed the delivery of miR-21-5p from colorectal cancer (CRC) cells to endothelial cells via exosomes increased the amount of miR-21-5p in recipient cells. MiR-21-5p suppressed Krev interaction trapped protein 1 (KRIT1) in recipient HUVECs and subsequently activated ß-catenin signaling pathway and increased their downstream targets VEGFa and Ccnd1, which consequently promoted angiogenesis and vascular permeability in CRC. A strong inverse correlation between miR-21-5p and KRIT1 expression levels was observed in CRC-adjacent vessels. Furthermore, miR-21-5p expression in circulating exosomes was markedly higher in CRC patients than in healthy donors. Thus, our data suggest that exosomal miR-21-5p is involved in angiogenesis and vascular permeability in CRC and may be used as a potential new therapeutic target.


Assuntos
Neoplasias Colorretais/irrigação sanguínea , Proteína KRIT1/metabolismo , MicroRNAs/metabolismo , Animais , Permeabilidade Capilar , Movimento Celular/fisiologia , Proliferação de Células/fisiologia , Embrião de Galinha , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Exossomos/genética , Exossomos/metabolismo , Células HCT116 , Células HT29 , Xenoenxertos , Células Endoteliais da Veia Umbilical Humana , Humanos , Proteína KRIT1/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , MicroRNAs/genética , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Microambiente Tumoral
17.
Waste Manag ; 127: 121-129, 2021 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-33933869

RESUMO

High solid anaerobic digestion (HSAD) is a promising technology for the treatment of organic waste. Mixing process in HSAD is quite difficult with long mixing time, poor homogenization, significant short-circuiting and stagnant zones. However, the mass transfer in mixing process in HSAD has not been visualized due to the lack of a proper method. In this study, a novel approach for experimentally quantifying the mass transfer in HSAD's mixing process was proposed in a mixing tank equipped with multistage impellers by means of the Laser Induced Fluorescence (LIF) technique. Flow field was investigated for better illustrating the mass transfer, thus Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD) technique were conducted for flow field measurement. The obtained results revealed that the feedstock tended to accumulate around the impeller in the HSAD system, especially near the 1st stage. The tracer diffused rapidly around the 1st impeller in t = 10 s, but the diffusion around the 2nd impeller was quite tough even after 4 h 08 min 23 s. And prolonging mixing time could not significantly improve the flow pattern along with the mixing. In this study, new insight was thrown into the visualization of the mass transfer in mixing process within a HSAD reactor. The visualization of mass transfer in the mixing process in HSAD could offer reference information to the study of the mixing process of HSAD even in full-scale.


Assuntos
Hidrodinâmica , Lasers , Anaerobiose , Reatores Biológicos , Reologia
18.
Bioact Mater ; 6(10): 3461-3472, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33817421

RESUMO

Facing the high incidence of skin diseases, it is urgent to develop functional materials with high bioactivity for wound healing, where reactive oxygen species (ROS) play an important role in the wound healing process mainly via adjustment of immune response and neovasculation. In this study, we developed a kind of bioabsorbable materials with ROS-mediation capacity for skin disease therapy. Firstly, redox-sensitive poly(N-isopropylacrylamide-acrylic acid) (PNA) nanogels were synthesized by radical emulsion polymerization method using a disulfide molecule as crosslinker. The resulting nanogels were then incorporated into the nanofibrous membrane of poly(l-lactic acid) (PLLA) via airbrushing approach to offer bioabsorbable membrane with redox-sensitive ROS-balance capacity. In vitro biological evaluation indicated that the PNA-contained bioabsorbable membrane improved cell adhesion and proliferation compared to the native PLLA membrane. In vivo study using mouse wound skin model demonstrated that PNA-doped nanofibrous membranes could promote the wound healing process, where the disulfide bonds in them were able to adjust the ROS level in the wound skin for mediation of redox potential to achieve higher wound healing efficacy.

19.
Carbohydr Polym ; 257: 117567, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33541628

RESUMO

This study investigated the role of various active species (OH, O, and H2O2) under solution plasma process (SPP) degradation based on the influence of different radical scavengers on the degradation effect and ESR spectra. The structures of oligochitosan with different radical scavengers were characterized by FT-IR, 1H NMR, and XRD analysis. The results indicated that OH, O, and H2O2 played important roles in SPP degradation. The degradation effect of the O was even higher than that of the OH. The physical effects (e.g. UV light and shockwaves) of SPP method or Fenton's reaction might contribute to the degradation treatment. Furthermore, the different scavengers could adjust the degradation effect of the corresponding free radicals. FT-IR, 1H NMR, and XRD analysis revealed that the primary chemical structure of chitosan was not changed by the scavengers. This study found that the controlled degradation by addition of a radical scavenger is feasible. Therefore, this study provided a straightforward analysis of the role of the free radicals and the controlled degradation of chitosan under SPP treatment, which will be beneficial to further develop SPP techniques for chitosan degradation.

20.
World J Surg Oncol ; 19(1): 50, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33588854

RESUMO

BACKGROUND: We invented a new antireflux anastomosis method for use in proximal gastrectomy for adenocarcinoma of the esophagogastric junction (AEG) and named it semi-embedded valve anastomosis (SEV). This study was conducted to compare and analyze the short-term efficacy and long-term prognosis of this anastomosis reconstruction method versus laparoscopic total gastrectomy (LTG). METHODS: We retrospectively analyzed the general data and surgical outcomes of patients with AEG who underwent three united laparoscopic proximal gastrectomy plus semi-embedded valve anastomosis (TULPG-SEV, N = 20) and LTG (N = 20) at our hospital from January 2015 to September 2017 and investigated the incidence of postoperative reflux esophagitis and postoperative nutritional status between the two groups. Survival analysis was also performed. RESULTS: The operative time (178.25 ± 15.41 vs 196.5 ± 21.16 min) and the gastrointestinal reconstruction time (19.3 ± 2.53 vs 34.65 ± 4.88 min) of the TULPG-SEV group were significantly less than that of the LTG group. There was no difference in intraoperative blood loss, length of hospital stay, and postoperative complications. There was no difference in the scores on the postoperative reflux disease questionnaires (RDQs) conducted 1 month (P = 0.501), 3 months (P = 0.238), and 6 months (P = 0.655) after surgery between the TULPG-SEV group and LTG group. Gastroscopy revealed 2 cases of reflux esophagitis (grade B or higher) in each group. The postoperative hemoglobin level was better in the TULPG-SEV group than in the LTG group, and the difference was most noticeable at 1 month after surgery (P = 0.024) and 3 months after surgery (P = 0.029). The levels of albumin and total protein were not significantly different between the groups. There were more patients with weight loss over 5 kg after surgery in the LTG group than in the TULPG-SEV group (P = 0.043). There was no significant difference in the 3-year overall survival rate between the two groups (P = 0.356). CONCLUSION: SEV has a certain antireflux effect and can reduce the anastomosis time. Proximal gastrectomy may be better than total gastrectomy for maintaining postoperative hemoglobin levels and reducing weight loss.


Assuntos
Adenocarcinoma , Laparoscopia , Neoplasias Gástricas , Adenocarcinoma/cirurgia , Anastomose Cirúrgica , Junção Esofagogástrica/cirurgia , Gastrectomia , Humanos , Complicações Pós-Operatórias/epidemiologia , Prognóstico , Estudos Retrospectivos , Neoplasias Gástricas/cirurgia , Resultado do Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...