Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
1.
Opt Express ; 31(26): 43390-43400, 2023 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-38178433

RESUMEN

We study a photonic band gap (PBG) material consisting of multiple waveguides. The multiconnected waveguides provide different paths for direct wave interference within the material. Using coaxial cables as waveguides, we are able to tune the PBG of the material. Using direct destructive interference between different paths of the waveguides, we experimentally observe a kind of PBG which is quite different from the traditional PBG that is caused by scattering in dielectrics with inhomogeneous refractive indices. Particularly, this newly observed PBG has an extremely strong wave attenuation, making electromagnetic (EM) waves in the PBG cannot even pass through one unit cell under certain conditions. We also systematically investigate the transmission of EM waves in our PBG materials and discuss the mechanism of band gap formation. Our results provide a new insight to develop new band gap materials for photons and phonons.

2.
Small ; 18(33): e2203283, 2022 08.
Artículo en Inglés | MEDLINE | ID: mdl-35871548

RESUMEN

Exploring antibacterial nanomaterials with excellent catalytic antibacterial properties has always been a hot research topic. However, the construction of nanomaterials with robust antibacterial activity at the atomic level remains a great challenge. Here a fully-exposed Pd cluster atomically-dispersed on nanodiamond-graphene (Pdn /ND@G) with excellent catalytic antibacterial properties is reported. The fully-exposed Pd cluster nanozyme provides atomically-dispersed Pd cluster sites that facilitate the activation of oxygen. Notably, the oxidase-like catalytic performance of the fully-exposed Pd cluster nanozyme is much higher than that of Pd single-atom oxidase mimic, Pd nanoparticles oxidase mimic and even the previously reported palladium-based oxidase mimics. Under the density functional theory (DFT) calculations, the Pd cluster sites can efficiently catalyze the decomposition of oxygen to generate reactive oxygen species, resulting in strong antibacterial properties. This research provides a valuable insight to the design of novel oxidase mimic and antibacterial nanomaterial.


Asunto(s)
Antibacterianos , Nanoestructuras , Antibacterianos/farmacología , Catálisis , Oxidorreductasas , Oxígeno
3.
Appl Opt ; 55(6): 1257-61, 2016 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-26906576

RESUMEN

The damage mechanism of a CCD detector was studied by building an experimental system containing a millisecond pulse laser irradiating a CCD detector. The experimental results show that the damage on the CCD detector was mainly thermal damage, along with mechanical damage. A melting phenomenon was caused by the thermal damage, so that a crater was observed on the surface of the CCD detector. Caused by melting of the polysilicon electrodes and a temperature rise in the silicon dioxide, the shift register impedance values were sharply reduced. Most of the substrate clock signals were broken and disappeared due to melting of channels in the silicon substrate layer, which caused a functional loss for the CCD detector. The mechanical damage on the melting edge of the CCD detector created heave; the temperature gradient caused this damage. In this paper, the decrease in vertical shift register impedance values was consistent with previous test results.

4.
RSC Med Chem ; 15(4): 1161-1175, 2024 Apr 24.
Artículo en Inglés | MEDLINE | ID: mdl-38665838

RESUMEN

PD-L1 is a transmembrane protein overexpressed by tumor cells. It binds to PD-1 on the surface of T-cells, suppresses T-cell activity and hinders the immune response against cancer. Clinically, several monoclonal antibodies targeting PD-1/PD-L1 have achieved significant success in cancer immunotherapy. Nevertheless, their disadvantages, such as unchecked immune responses, high cost and long half-life, stimulated pharmacologists to develop small-molecule inhibitors targeting PD-1/PD-L1. After a batch of excellent inhibitors with a biphenyl core structure were firstly reported by BMS, more and more researchers focused on small-molecule inhibitors targeting PD-L1 rather than PD-1. Numerous small-molecule inhibitors were extensively designed and synthesized in the past few years. In this paper, the structural characteristics of PD-L1 and complexes of PD-L1 with its inhibitors are elaborated and small molecule inhibitors developed in the last decade are summarized as well. This paper aims to provide insights into further designing and synthesis of small molecule inhibitors targeting PD-L1.

5.
RSC Adv ; 13(47): 33204-33209, 2023 Nov 07.
Artículo en Inglés | MEDLINE | ID: mdl-37954426

RESUMEN

Iridoid glycoside, which belongs to the polyhydroxy compound, is a kind of active ingredient of traditional Chinese medicine with a wide range of sources, and has many pharmacological effects such as anti-cancer, anti-inflammatory, anti-virus, hypoglycemic and so on. Its structure contains many hydroxyl groups, including two primary hydroxyl groups. The chemical reactivity of primary hydroxyl groups has very little difference, so it is very important to control the selectivity of hydroxyl groups under certain conditions. In this paper, the difference between the two primary hydroxyl groups in iridoid glycoside was calculated based on computer simulation and verified this result through designed experiments. This study will provide an important way for site-directed modification of hydroxyl in iridoid glycoside in the future.

6.
Korean J Pain ; 36(4): 465-472, 2023 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-37752665

RESUMEN

Background: Percutaneous radiofrequency thermocoagulation (RFTC) has been widely utilized in the management of trigeminal neuralgia. Despite using image guidance, accurate needle positioning into the target area still remains a critical element for achieving a successful outcome. This study was performed to precisely clarify the anatomical information required to ensure that the electrode tip is placed on the sensory component of the mandibular nerve (MN) at the foramen ovale (FO) level. Methods: The study used 50 hemi-half heads from 26 South Korean adult cadavers. Results: The cross-sectioned anterior and posterior divisions of the MN at the FO level could be distinguished based on an irregular boundary and color difference. The anterior division was clearly brighter than the posterior one. The anterior division of the MN at the FO level was located at the whole anterior (38.0%), anteromedial (6.0%), anterior center (8.0%), and anterolateral (22.0%) parts. The posterior division was often located at the whole posterior or posterolateral parts of the MN at the FO level. The anterior divisions covered the whole MN except for the medial half of the posterolateral part in the overwrapped images of the cross-sectional areas of the MN at the FO level. The cross-sectional areas of the anterior divisions were similar in males and females, whereas those of the posterior divisions were significantly larger in males (P = 0.004). Conclusions: The obtained anatomical information is expected to help physicians reduce unwanted side effects after percutaneous RFTC within the FO for the MN.

7.
Appl Bionics Biomech ; 2022: 7641048, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35126662

RESUMEN

The fast advancement and deployment of sequencing technologies after the Human Genome Project have greatly increased our knowledge of the eukaryotic genome sequences. However, due to technological concerns, high-quality genomic data has been confined to a few key organisms. Moreover, our understanding of which portions of genomes make up genes and which transcript isoforms synthesize these genes is scarce. Therefore, the current study has been designed to explore the reliability of the tiger lily (Lilium lancifolium Thunb) transcriptome. The PacBio-SMRT was used for attaining the complete transcriptomic profile. We obtained a total of 815,624 CCS (Circular Consensus Sequence) reads with an average length of 1295 bp. The tiger lily transcriptome has been sequenced for the first time using third-generation long-read technology. Furthermore, unigenes (38,707), lncRNAs (6852), and TF members (768) were determined based on the transcriptome data, followed by evaluating SSRs (3319). It has also been revealed that 105 out of 128 primer pairs effectively amplified PCR products. Around 15,608 transcripts were allocated to 25 distinct KOG Clusters, and 10,706 unigenes were grouped into 52 functional categories in the annotated transcripts. Until now, no tiger lily lncRNAs have been discovered. Results of this study may serve as an extensive set of reference transcripts and help us learn more about the transcriptomes of tiger lilies and pave the path for further research.

8.
J Clin Med ; 9(12)2020 Dec 02.
Artículo en Inglés | MEDLINE | ID: mdl-33276698

RESUMEN

Cervical facet joint (CFJ) syndrome is a common cause of neck pain. For its diagnosis and treatment, CFJ injection with arthrogram is generally performed. This study aimed to investigate the frequency of extra-CFJ flow on CFJ arthrograms during injections and its differences according to age, sex, and cervical vertebral level. We analyzed 760 CFJ arthrograms administrated to 208 patients diagnosed with CFJ syndrome. Arthrograms at each vertebral level were collected to evaluate the normal CFJ and extra-CFJ flow. The primary and secondary outcomes were frequency of extra-CFJ flow according to cervical vertebral level, age, and sex and according to pairwise cervical levels, respectively. Extra-CFJ flow at the cervical spine occurred during 179 injections, and the overall incidence was 3.3-36.2% at different cervical levels. The incidence of extra-CFJ flow at each cervical vertebral level according to age and sex was not significant. Extra-CFJ flow was the highest at C6 and C7, but there was no statistical significance. Extra-CFJ flow was higher at lower vertebral levels (C5-C7) than at upper levels (C3 and C4). Additional clinical studies and anatomical evaluations are needed to support its clinical value and enable the development of new injection techniques.

9.
Carbohydr Polym ; 214: 100-109, 2019 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-30925977

RESUMEN

Carboxylated cellulose nanocrystals (CCNs), as one of nanocellulose are promising hydrophilic biomass materials for drug delivery. In this work, a series of amphiphilic carboxylated cellulose-graft-Poly(L-lactide) (CC-g-PLLA) copolymers were synthesized via ring-opening polymerization (ROP) method. The copolymers were characterized by 1H-NMR, FT-IR, WXRD and TGA, and their solubility in organic solvents was improved. Then, these amphiphilic copolymers were self-assembled into nanoparticles for delivery of anticancer drug oleanolic acid (OA). The copolymer (DSPLLA 2.03) nanoparticles displayed the smallest size (196.82 ± 9.14 nm) and the highest drug loading efficiency (24.76 ± 0.58%). The nanoparticles exhibited a spherical shape, well water solubility of OA (16.9 mg/mL) and a prolonged drug release (120 h). In vitro and In vivo study indicated that the nanoparticles maintained cytotoxicity to 4T1 cells and MCF-7 cells and displayed high antitumor efficiency. The amphiphilic CC-g-PLLA copolymer nanoparticles provide a novel platform for drug delivery.

10.
Mater Sci Eng C Mater Biol Appl ; 86: 28-41, 2018 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-29525094

RESUMEN

The application of non-toxic carriers to increase drug loading, multi-drug delivery, and extremely small size of nano-drugs to construct a tremendous transmission system is the goal for all researchers to be pursued. The proposal of natural pectin nano-platform for delivery of multiple drugs is critical for biomedical research, especially a particle size of below 100nm with high yield. Here we design a new core-shell structure pectin-eight-arm polyethylene glycol-ursolic acid/hydrooxycampothecin nanoparticle (Pec-8PUH NPs) through a special self-assembly method for stabilizing and dispersing particles, improving water-solubility, and achieving drug controlled release. The obtained Pec-8PUH NPs possessed appropriate size (~91nm), drug-loaded efficiency and encapsulation efficiency through the regulation of eight-arm polyethylene glycol. In addition, Pec-8PUH NPs could enhance cell cytotoxicity, shorten blood retention time (7.3-fold UA, 7.2-fold HCPT) and more effective cellular uptake than free drugs, which exhibited an obvious synergistic effect of UA and HCPT by the co-delivery. 4T1 tumor-bearing mice also showed a higher survival rate than free UA and free HCPT. The result further shows that this novel drug delivery system has a promising potential for anti-cancer combination therapy.


Asunto(s)
Antineoplásicos/química , Portadores de Fármacos/química , Nanopartículas/química , Pectinas/química , Polietilenglicoles/química , Animales , Antineoplásicos/metabolismo , Antineoplásicos/uso terapéutico , Camptotecina/análogos & derivados , Camptotecina/química , Camptotecina/metabolismo , Camptotecina/uso terapéutico , Línea Celular Tumoral , Supervivencia Celular , Portadores de Fármacos/toxicidad , Liberación de Fármacos , Femenino , Semivida , Hemólisis/efectos de los fármacos , Humanos , Ratones , Ratones Endogámicos BALB C , Nanopartículas/toxicidad , Neoplasias/tratamiento farmacológico , Neoplasias/patología , Tamaño de la Partícula , Trasplante Heterólogo , Triterpenos/química , Triterpenos/metabolismo , Ácido Ursólico
11.
Zhonghua Jie He He Hu Xi Za Zhi ; 28(6): 403-6, 2005 Jun.
Artículo en Zh | MEDLINE | ID: mdl-16008979

RESUMEN

OBJECTIVE: To evaluate the accuracy and applicability of species identification method of Mycobacteria by applying gas chromatography analysis of whole-cell fatty acid. METHODS: Species identification of 14 reference strains and 727 clinical isolates of Mycobacteria were performed by using MIDI Sherlock Microbial Identification System (MIS)4.0 based on gas chromatography analysis of whole-cell fatty acid, and the results were compared with those of conventional species identification method. RESULTS: (1) By using the conventional method, all 14 reference strains were identified correctly. Except for Mycobacterium.vaccae, the result obtained by MIS were identical to that of conventional method. (2) Among 625 clinical isolates identified as Mycobacterium tuberculosis (MTB) and Mycobacterium bovis, 45 strains were mistakenly identified as Nontuberculous Mycobacteria (NTM) by MIS. Its accuracy was 93%. For 102 NTM strains, results of group identification showed no difference between the two methods. However, 7 results of species identification were not consistent, the accuracy being 93%. (3) MIS mainly mistook MTB for Mycobacterium gastri, Mycobacterium trivial and Mycobacterium smegmatis, and Mycobacterium scrofulaceum for Mycobacterium gordonae among NTM. CONCLUSIONS: The results of species identification of Mycobacteria by applying gas chromatography analysis of whole-cell fatty acid are in accordance with those of conventional method for the majority of the strains, and MIS can identify Mycobacteria to species level by a single experiment. It can be considered as a good method for species identification of Mycobacteria in terms of its accuracy and applicability.


Asunto(s)
Técnicas de Tipificación Bacteriana/métodos , Cromatografía de Gases/métodos , Ácidos Grasos/análisis , Mycobacterium/aislamiento & purificación , Humanos , Mycobacterium/clasificación , Especificidad de la Especie
12.
Zhonghua Jie He He Hu Xi Za Zhi ; 28(2): 117-21, 2005 Feb.
Artículo en Zh | MEDLINE | ID: mdl-15854395

RESUMEN

OBJECTIVE: To develop a rat model of tuberculous pleurisy and to explore the mechanism of intrapleural inflammatory and immunological responses. METHODS: Fifty Wistar rats were injected intrapleurally with 0.03 mg of standard human mycobacterium tuberculous bacilli H37Rv each. The rats were killed in group on days 1, 2, 3, 5, 7, 10, 15, 20, 30 and 60 after the day of intrapleural injection. The thorax was opened and the amount of pleural effusion was recorded, and histopathology of pleural tissues and lung tissues were observed. The white blood cell (WBC) count and differentials, levels of total protein (TP), glucose (GLU) and lactic dehydrogenase (LDH) of pleural effusions were determined. Pleural fluid was analyzed for the levels of soluble intercellular adhesion molecule-1 (sICAM-1), transforming growth factor beta1 (TGF-beta1) and interferon gamma (IFN-gamma) by using appropriate bioassays. Ten rats were intrapleurally received 2 ml of normal saline and another 10 rats received 2 ml of undiluted PPD solution each as control. RESULTS: Bilateral pleural effusions appeared within 15 days in all rats intrapleurally received tuberculous bacilli. The peak amount of pleural fluid was on day 5 (6.7 +/- 0.5 ml). The neutrophils were the predominant cells for the first 24 hours, and then were followed by lymphocytes. In the pleural fluid, total protein concentration was between 51-55 g/L. The levels of glucose and LDH were 5.2 mmol/L and 18.1 micromol.s(-1).L(-1) on day 1 and changed to 2.8 mmol/L and 28.9 micromol.s(-1).L(-1) on day 15 respectively. The biochemistry parameters were in accordance with characteristics of tuberculous pleurisy. The sICAM-1 level increased early (21.9 ng/ml on day 1) and peaked on day 3 (38.0 ng/ml), then decreased over time (4.4 ng/ml on day 15). The level of IFN-gamma was 41.2 pg/ml on day 1 and increased and maintained at high levels over time. TGF-beta1 levels increased and peaked on day 7 (47.2 ng/ml), and then on day 15 decreased to a level lower than that of day 1. The ratio of IFN-gamma/TGF-beta1 increased from 1.32 on day 1 to 5.69 on day 15. Correlation analysis showed that sICAM-1 and IFN-gamma were closely related with WBC count and its differentials, as well as with LDH levels. Histopathological study revealed early pleural inflammation and late caseation. CONCLUSIONS: Wistar rats can be used as an experimental model for tuberculous pleurisy. Tuberculous inflammatory and immunological responses in acute tuberculous pleurisy is enhanced rather than suppressed.


Asunto(s)
Molécula 1 de Adhesión Intercelular/biosíntesis , Pleura/metabolismo , Derrame Pleural/metabolismo , Factor de Crecimiento Transformador beta/biosíntesis , Tuberculosis Pleural/inmunología , Tuberculosis Pleural/metabolismo , Animales , Modelos Animales de Enfermedad , Femenino , Interferón gamma/biosíntesis , Recuento de Leucocitos , Recuento de Linfocitos , Mycobacterium tuberculosis , Pleura/patología , Derrame Pleural/inmunología , Ratas , Ratas Wistar , Tuberculosis Pleural/etiología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA