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1.
Nature ; 610(7930): 54-60, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36171286

RESUMO

Integrated photonics has profoundly affected a wide range of technologies underpinning modern society1-4. The ability to fabricate a complete optical system on a chip offers unrivalled scalability, weight, cost and power efficiency5,6. Over the last decade, the progression from pure III-V materials platforms to silicon photonics has significantly broadened the scope of integrated photonics, by combining integrated lasers with the high-volume, advanced fabrication capabilities of the commercial electronics industry7,8. Yet, despite remarkable manufacturing advantages, reliance on silicon-based waveguides currently limits the spectral window available to photonic integrated circuits (PICs). Here, we present a new generation of integrated photonics by directly uniting III-V materials with silicon nitride waveguides on Si wafers. Using this technology, we present a fully integrated PIC at photon energies greater than the bandgap of silicon, demonstrating essential photonic building blocks, including lasers, amplifiers, photodetectors, modulators and passives, all operating at submicrometre wavelengths. Using this platform, we achieve unprecedented coherence and tunability in an integrated laser at short wavelength. Furthermore, by making use of this higher photon energy, we demonstrate superb high-temperature performance and kHz-level fundamental linewidths at elevated temperatures. Given the many potential applications at short wavelengths, the success of this integration strategy unlocks a broad range of new integrated photonics applications.

2.
J Biomol NMR ; 78(1): 19-30, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38102490

RESUMO

A recently developed homonuclear dipolar recoupling scheme, Adiabatic Linearly FREquency Swept reCOupling (AL FRESCO), was applied to record two-dimensional (2D) 15N-15N correlations on uniformly 15N-labeled GB1 powders. A major feature exploited in these 15N-15N correlations was AL FRESCO's remarkably low RF power demands, which enabled seconds-long mixing schemes when establishing direct correlations. These 15N-15N mixing schemes proved efficient regardless of the magic-angle spinning (MAS) rate and, being nearly free from dipolar truncation effects, they enabled the detection of long-range, weak dipolar couplings, even in the presence of strong short-range dipolar couplings. This led to a connectivity information that was significantly better than that obtained with spontaneously proton-driven, 15N spin-diffusion experiments. An indirect approach producing long-range 15N-15N correlations was also tested, relying on short (ms-long) 1HN-1HN mixings schemes while applying AL FRESCO chirped pulses along the 15N channel. These indirect mixing schemes produced numerous long-distance Ni-Ni±n (n = 2 - 5) correlations, that might be useful for characterizing three-dimensional arrangements in proteins. Once again, these AL FRESCO mediated experiments proved more informative than variants based on spin-diffusion-based 1HN-1HN counterparts.


Assuntos
Peptídeos , Proteínas , Ressonância Magnética Nuclear Biomolecular/métodos , Peptídeos/química , Espectroscopia de Ressonância Magnética/métodos , Proteínas/química , Imageamento por Ressonância Magnética , Prótons
3.
Small ; 20(35): e2401248, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38639029

RESUMO

Chlorine has been supplied by the chlor-alkali process that deploys dimensionally stable anodes (DSAs) for the electrochemical chlorine evolution reaction (ClER). The paramount bottlenecks have been ascribed to an intensive usage of precious elements and inevitable competition with the oxygen evolution reaction. Herein, a unique case of Ru2+-O4 active motifs anchored on Magnéli Ti4O7 (Ru-Ti4O7) via a straightforward wet impregnation and mild annealing is reported. The Ru-Ti4O7 performs radically active ClER with minimal deployment of Ru (0.13 wt%), both in 5 m NaCl (pH 2.3) and 0.1 m NaCl (pH 6.5) electrolytes. Scanning electrochemical microscopy demonstrates superior ClER selectivity on Ru-Ti4O7 compared to the DSA. Operando X-ray absorption spectroscopy and density functional theory calculations reveal a universally active ClER (over a wide range of pH and [Cl-]), through a direct adsorption of Cl- on Ru2+-O4 sites as the most plausible pathway, together with stabilized ClO* at low [Cl-] and high pH.

4.
Bioconjug Chem ; 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39172920

RESUMO

Single-domain antibodies, or nanobodies (Nbs), are promising biomolecules for use in molecular imaging due to their excellent affinity, specificity, and fast clearance from the blood. Given their short blood half-life, pairing Nbs with short-lived imaging radioisotopes is desirable. Because fluorine-18 (18F) is routinely used for clinical imaging, it is an attractive radioisotope for Nbs. We report a novel sortase-based, site-specific 18F-labeling method applied to three nanobodies. Labeled nanobodies were synthesized either by a two-step indirect radiolabeling method in one pot or by a one-step direct labeling method using a sortase-mediated conjugation of either the radiolabeled chelator (H-GGGK((±)-Al[18F]FH3RESCA)-NH2) or the unlabeled chelator (H-GGGK((±)-H3RESCA)-NH2) followed by labeling with Al[18F]F, respectively. The overall radiochemical yields were 15-43% (n = 22, decay-corrected) in 70 min (indirect labeling) and 23-58% (n = 12, decay-corrected) in 50 min (direct labeling). The radiochemical purities of the labeled nanobodies prepared by both methods were >98% with a specific activity of 400-600 Ci/mmol (n = 22) for each of the three Nbs tested and exhibited excellent stability profiles under physiological conditions. This simple, site-specific, reproducible, and generalizable 18F-labeling method to prepare nanobodies (Nb-Al[18F]F-RESCA) or other low molecular weight biomolecules can easily be adopted in various settings for preclinical and clinical studies.

5.
Bioorg Chem ; 152: 107720, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39182259

RESUMO

Pre-eclampsia (PE) is classified as pregnancy-specific hypertensive disease and responsible for severe fetal and maternal morbidity and mortality, which influenced an approximate 3 âˆ¼ 8 % of all pregnancies in both developed and developing countries. However, the exact pathological mechanism underlying PE has not been elucidated and it is urgent to find innovate pharmacotherapeutic agents for PE. Recent studies have reported that a crucial part of the etiology of PE is played by placental oxidative stress. Therefore, to treat PE, a possible treatment approach is to mitigate the placental oxidative stress. Alpinumisoflavone (AIF) is a prenylated isoflavonoid originated in mandarin melon berry called Cudrania tricuspidate, and is well known for its versatile pharmacotherapeutic properties, including anti-fibrotic, anti-inflammatory, anti-tumor, and antioxidant activity. However, protective property of AIF on extravillous trophoblast (EVT) under placental oxidative stress has not been elucidated yet. Therefore, we assessed stimulatory effects of AIF on the viability, invasion, migration, mitochondria function in the representative EVT cell line, HTR-8/SVneo cell. Moreover, protective activities of AIF from H2O2 were confirmed, in terms of reduction in apoptosis, ROS production, and depolarization of mitochondrial membrane. Furthermore, we confirmed the direct interaction of AIF with sirtuin1 (SIRT1) using molecular docking analysis and SIRT1-mediated signaling pathways associated with the protective effects of AIF on HTR-8/SVneo cells under oxidative stress. Finally, beneficial efficacy of AIF against oxidative stress was further confirmed using BeWo cells, syncytiotrophoblast cell lines. These results suggest that AIF may ameliorate H2O2-induced intracellular damages through SIRT1 activation in human trophoblast cells.

6.
J Biomol NMR ; 77(5-6): 217-228, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37804349

RESUMO

Nuclear magnetic resonance is a crucial technique for studying biological complexes, as it provides precise structural and dynamic information at the atomic level. However, the process of assigning resonances can be time-consuming and challenging, particularly in cases where peaks overlap, or the data quality is poor. In this paper, we present TINTO (Two and three-dimensional Imaging for NMR sTrip Operation via CV/ML), an advanced semiautomatic toolset for NMR resonance assignment. TINTO comprises two separate tools, each tailored for either two-dimensional or three-dimensional imaging. The toolset utilizes a computer-vision approach and a machine learning approach, specifically structural similarity index and principal components analysis, to perform visual similarity searches of resonances and quickly locate similar strips, and in that way overcome the challenges associated with peak overlap without requiring peak picking. Our tool offers a user-friendly interface and has the potential to enhance the efficiency and accuracy of NMR resonance assignment, particularly in complex cases. This advancement holds promising implications for furthering our understanding of biological systems at the molecular level. TINTO is pre-installed in the POKY suite, which is available at https://poky.clas.ucdenver.edu .


Assuntos
Computadores , Proteínas , Ressonância Magnética Nuclear Biomolecular/métodos , Proteínas/química , Espectroscopia de Ressonância Magnética , Imageamento por Ressonância Magnética , Algoritmos
7.
Environ Sci Technol ; 57(47): 18529-18537, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-36245147

RESUMO

This study valorized scanning electrochemical microscopy (SECM) for the detection of dissolved O3, which is increasingly in demand for water treatment. Au ultramicroelectrodes biased at 0.62 V RHE provided superior activity and selectivity for O3 reduction, compared to Pt analogues. It allowed quantitative in situ interrogation of ozone evolution reaction (OZER) electrocatalysts with unprecedented estimations on the OZER overpotential. The difference in onset potentials between the OZER and the competing oxygen evolution reaction (OER) primarily accounted for the OZER current efficiency (CE) on boron-doped diamond (BDD, 1.4% at 10 mA cm-2 in 0.5 M H2SO4), Ni-Sb-doped SnO2 (NSS, 10.8%), and SiOx-coated NSS (NSS/SiOx, 34.4%). SECM areal scans in tandem with elemental mapping perspicuously visualized the improved OZER activity by the SiOx overlayer on NSS. A shift in the charge transfer coefficient further rationalized the elevated OZER selectivity on NSS/SiOx, in association with the weakened Sn-O bond strength confirmed by valence band X-ray photoelectron spectra. The invigorated OZER on NSS/SiOx effectively accelerated the degradation of a model aqueous pollutant (4-chlorophenol).


Assuntos
Ozônio , Purificação da Água , Microscopia Eletroquímica de Varredura , Oxirredução , Estresse Oxidativo
8.
Bioinformatics ; 37(18): 3041-3042, 2021 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-33715003

RESUMO

SUMMARY: The need for an efficient and cost-effective method is compelling in biomolecular NMR. To tackle this problem, we have developed the Poky suite, the revolutionized platform with boundless possibilities for advancing research and technology development in signal detection, resonance assignment, structure calculation and relaxation studies with the help of many automation and user interface tools. This software is extensible and scalable by scripting and batching as well as providing modern graphical user interfaces and a diverse range of modules right out of the box. AVAILABILITY AND IMPLEMENTATION: Poky is freely available to non-commercial users at https://poky.clas.ucdenver.edu. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Imageamento por Ressonância Magnética , Software , Ressonância Magnética Nuclear Biomolecular/métodos , Automação
9.
Bioinformatics ; 37(8): 1176-1177, 2021 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-32926121

RESUMO

MOTIVATION: Correlated Nuclear Magnetic Resonance (NMR) chemical shift changes identified through the CHEmical Shift Projection Analysis (CHESPA) and CHEmical Shift Covariance Analysis (CHESCA) reveal pathways of allosteric transitions in biological macromolecules. To address the need for an automated platform that implements CHESPA and CHESCA and integrates them with other NMR analysis software packages, we introduce here integrated plugins for NMRFAM-SPARKY that implement the seamless detection and visualization of allosteric networks. AVAILABILITY AND IMPLEMENTATION: CHESCA-SPARKY and CHESPA-SPARKY are available in the latest version of NMRFAM-SPARKY from the National Magnetic Resonance Facility at Madison (http://pine.nmrfam.wisc.edu/download_packages.html), the NMRbox Project (https://nmrbox.org) and to subscribers to the SBGrid (https://sbgrid.org). The assigned spectra involved in this study and tutorial videos using this dataset are available at https://sites.google.com/view/chescachespa-sparky. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics Online.


Assuntos
Análise de Dados , Software , Espectroscopia de Ressonância Magnética , Ressonância Magnética Nuclear Biomolecular , Proteínas
10.
Eur J Nucl Med Mol Imaging ; 49(12): 4073-4087, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35680737

RESUMO

PURPOSE: Hydrogen sulfide (H2S) plays important roles in brain pathophysiology. However, nuclear imaging probes for the in vivo detection of brain H2S in living animals have not been developed. Here, we report the first nuclear imaging probe that enables in vivo imaging of endogenous H2S in the brain of live mice. METHODS: Utilizing a bis(thiosemicarbazone) backbone, a fluorescent ATSM-FITC conjugate was synthesized. Its copper complex, Cu(ATSM-FITC) was thoroughly tested as a biosensor for H2S. The same ATSM-FITC ligand was quantitatively labeled with [64Cu]CuCl2 to obtain a radioactive [64Cu][Cu(ATSM-FITC)] imaging probe. Biodistribution and positron emission tomography (PET) imaging studies were performed in healthy mice and neuroinflammation models. RESULTS: The Cu(ATSM-FITC) complex reacts instantly with H2S to release CuS and becomes fluorescent. It showed excellent reactivity, sensitivity, and selectivity to H2S. Endogenous H2S levels in living cells were successfully detected by fluorescence microscopy. Exceptionally high brain uptake of [64Cu][Cu(ATSM-FITC)] (> 9% ID/g) was observed in biodistribution and PET imaging studies. Subtle changes in brain H2S concentrations in live mice were accurately detected by quantitative PET imaging. Due to its dual modality feature, increased H2S levels in neuroinflammation models were characterized at the subcellular level by fluorescence imaging and at the whole-body scale by PET imaging. CONCLUSION: Our biosensor can be readily utilized to study brain H2S function in live animal models and shows great potential as a novel imaging agent for diagnosing brain diseases.


Assuntos
Complexos de Coordenação , Sulfeto de Hidrogênio , Compostos Organometálicos , Tiossemicarbazonas , Animais , Encéfalo/diagnóstico por imagem , Cobre , Fluoresceína-5-Isotiocianato , Corantes Fluorescentes , Ligantes , Camundongos , Doenças Neuroinflamatórias , Distribuição Tecidual
11.
Mar Drugs ; 20(8)2022 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-35892941

RESUMO

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive types of cancer and exhibits a devastating 5-year survival rate. The most recent procedure for the treatment of PDAC is a combination of several conventional chemotherapeutic agents, termed FOLFIRINOX, that includes irinotecan, leucovorin, oxaliplatin, and 5-fluorouracil (5-FU). However, ongoing treatment using these agents is challenging due to their severe side effects and limitations on the range of patients available for PDAC. Therefore, safer and more innovative anticancer agents must be developed. The anticarcinoma activity of matairesinol that can be extracted from seagrass has been reported in various types of cancer, including prostate, breast, cervical, and pancreatic cancer. However, the molecular mechanism of effective anticancer activity of matairesinol against pancreatic cancer remains unclear. In the present study, we confirmed the inhibition of cell proliferation and progression induced by matairesinol in representative human pancreatic cancer cell lines (MIA PaCa-2 and PANC-1). Additionally, matairesinol triggers apoptosis and causes mitochondrial impairment as evidenced by the depolarization of the mitochondrial membrane, disruption of calcium, and suppression of cell migration and related intracellular signaling pathways. Finally, matairesinol exerts a synergistic effect with 5-FU, a standard anticancer agent for PDAC. These results demonstrate the therapeutic potential of matairesinol in the treatment of PDAC.


Assuntos
Antineoplásicos , Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Ductal Pancreático/tratamento farmacológico , Carcinoma Ductal Pancreático/metabolismo , Carcinoma Ductal Pancreático/patologia , Linhagem Celular Tumoral , Fluoruracila/farmacologia , Furanos , Humanos , Lignanas , Masculino , Mitocôndrias , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas
12.
Sensors (Basel) ; 22(24)2022 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-36560269

RESUMO

Chemical agents are one of the major threats to soldiers in modern warfare, so it is so important to detect chemical agents rapidly and accurately on battlefields. Raman spectroscopy-based detectors are widely used but have many limitations. The Raman spectrum changes unpredictably due to various environmental factors, and it is hard for detectors to make appropriate judgments about new chemical substances without prior information. Thus, the existing detectors with inflexible techniques based on determined rules cannot deal with such problems flexibly and reactively. Artificial intelligence (AI)-based detection techniques can be good alternatives to the existing techniques for chemical agent detection. To build AI-based detection systems, sufficient amounts of data for training are required, but it is not easy to produce and handle fatal chemical agents, which causes difficulty in securing data in advance. To overcome the limitations, in this paper, we propose the distributed Raman spectrum data augmentation system that leverages federated learning (FL) with deep generative models, such as generative adversarial network (GAN) and autoencoder. Furthermore, the proposed system utilizes various additional techniques in combination to generate a large number of Raman spectrum data with reality along with diversity. We implemented the proposed system and conducted diverse experiments to evaluate the system. The evaluation results validated that the proposed system can train the models more quickly through cooperation among decentralized troops without exchanging raw data and generate realistic Raman spectrum data well. Moreover, we confirmed that the classification model on the proposed system performed learning much faster and outperformed the existing systems.


Assuntos
Inteligência Artificial , Aprendizagem , Redes de Comunicação de Computadores , Julgamento
13.
Int J Mol Sci ; 23(6)2022 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-35328522

RESUMO

Proteins from Sulfolobus solfataricus (S. solfataricus), an extremophile, are active even at high temperatures. The single-stranded DNA (ssDNA) binding protein of S. solfataricus (SsoSSB) is overexpressed to protect ssDNA during DNA metabolism. Although SsoSSB has the potential to be applied in various areas, its structural and ssDNA binding properties at high temperatures have not been studied. We present the solution structure, backbone dynamics, and ssDNA binding properties of SsoSSB at 50 °C. The overall structure is consistent with the structures previously studied at room temperature. However, the loop between the first two ß sheets, which is flexible and is expected to undergo conformational change upon ssDNA binding, shows a difference from the ssDNA bound structure. The ssDNA binding ability was maintained at high temperature, but different interactions were observed depending on the temperature. Backbone dynamics at high temperature showed that the rigidity of the structured region was well maintained. The investigation of an N-terminal deletion mutant revealed that it is important for maintaining thermostability, structure, and ssDNA binding ability. The structural and dynamic properties of SsoSSB observed at high temperature can provide information on the behavior of proteins in thermophiles at the molecular level and guide the development of new experimental techniques.


Assuntos
Proteínas Arqueais , Sulfolobus solfataricus , Proteínas Arqueais/metabolismo , Biofísica , DNA de Cadeia Simples/metabolismo , Proteínas de Ligação a DNA/metabolismo , Ressonância Magnética Nuclear Biomolecular , Ligação Proteica , Sulfolobus solfataricus/metabolismo
14.
Biophys J ; 120(20): 4600-4607, 2021 10 19.
Artigo em Inglês | MEDLINE | ID: mdl-34461106

RESUMO

ATP7A and ATP7B are structurally similar but functionally distinct active copper transporters that regulate copper levels in the human cells and deliver copper to the biosynthetic pathways. Both proteins have a chain of six cytosolic metal-binding domains (MBDs) believed to be involved in the copper-dependent regulation of the activity and intracellular localization of these enzymes. Although all the MBDs are quite similar in structure, their spacing differs markedly between ATP7A and ATP7B. We show by NMR that the long polypeptide between MBD1 and MBD2 of ATP7A forms an additional seventh metastable domain, which we called HMA1A (heavy metal associated domain 1A). The structure of HMA1A resembles the MBDs but contains no copper-binding site. The HMA1A domain, which is unique to ATP7A, may modulate regulatory interactions between MBD1-3, contributing to the distinct functional properties of ATP7A and ATP7B.


Assuntos
ATPases Transportadoras de Cobre , Cobre , Sítios de Ligação , Cobre/metabolismo , ATPases Transportadoras de Cobre/genética , Humanos , Domínios Proteicos
15.
Biochem Biophys Res Commun ; 568: 23-29, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34174538

RESUMO

Gadolinium neutron capture therapy (GdNCT) is a form of binary radiotherapy. It utilizes nuclear reactions that occur when gadolinium-157 is irradiated with thermal neutrons, producing high-energy γ-rays and Auger electrons. Herein, we evaluate the potential of GdNCT for cancer treatment using PEGylated liposome incorporated with an FDA-approved MRI contrast agent. The clinical gadolinium complex (Gadovist®) was successfully encapsulated inside the aqueous core of PEGylated liposomes by repeated freeze and thaw cycling. At a concentration of 152 µM Gd, the Gd-liposome showed high cytotoxicity upon thermal-neutron irradiation. In animal experiments, when a CT26 tumor model was administered with Gd-liposomes (19 mg 157Gd per kg) followed by 20-min irradiation of thermal neutron at a flux of 1.94 × 104 cm-2 s-1, tumor growth was suppressed by 43%, compared to that in the control group, on the 23rd day of post-irradiation. After two-cycle GdNCT treatment at a 10-day interval, tumor growth was more efficiently retarded. On the 31st day after irradiation, the weight of the excised tumor in the GdNCT group (38 mg 157Gd per kg per injection) was only 30% of that of the control group. These results demonstrate the potential of GdNCT using PEGylated liposomes containing MRI contrast agents in cancer treatment.


Assuntos
Gadolínio/administração & dosagem , Isótopos/administração & dosagem , Lipossomos/química , Neoplasias/radioterapia , Terapia por Captura de Nêutron , Animais , Linhagem Celular Tumoral , Feminino , Gadolínio/uso terapêutico , Humanos , Isótopos/uso terapêutico , Camundongos Endogâmicos BALB C , Terapia por Captura de Nêutron/métodos , Polietilenoglicóis/química
16.
Bioinformatics ; 36(9): 2915-2916, 2020 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-31930377

RESUMO

MOTIVATION: Two-dimensional [15N-1H] separated local field solid-state nuclear magnetic resonance (NMR) experiments of membrane proteins aligned in lipid bilayers provide tilt and rotation angles for α-helical segments using Polar Index Slant Angle (PISA)-wheel models. No integrated software has been made available for data analysis and visualization. RESULTS: We have developed the PISA-SPARKY plugin to seamlessly integrate PISA-wheel modeling into the NMRFAM-SPARKY platform. The plugin performs basic simulations, exhaustive fitting against experimental spectra, error analysis and dipolar and chemical shift wave plotting. The plugin also supports PyMOL integration and handling of parameters that describe variable alignment and dynamic scaling encountered with magnetically aligned media, ensuring optimal fitting and generation of restraints for structure calculation. AVAILABILITY AND IMPLEMENTATION: PISA-SPARKY is freely available in the latest version of NMRFAM-SPARKY from the National Magnetic Resonance Facility at Madison (http://pine.nmrfam.wisc.edu/download_packages.html), the NMRbox Project (https://nmrbox.org) and to subscribers of the SBGrid (https://sbgrid.org). The pisa.py script is available and documented on GitHub (https://github.com/weberdak/pisa.py) along with a tutorial video and sample data. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Assuntos
Proteínas de Membrana , Software , Bicamadas Lipídicas , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Ressonância Magnética Nuclear Biomolecular
17.
Pestic Biochem Physiol ; 177: 104893, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34301355

RESUMO

Pesticides, which are used in agriculture and forestry to eliminate insects, are a major cause of environmental pollution. Among them, diflubenzuron (DFB), 1-(4-chlorophenyl)-3-(2,6-difluorobenzoyl) urea, is a common benzoylurea insecticide that hinders larval development, primarily in Aedes aegypti larvae. Many experts have announced the biological toxicity of DFB in various species. However, the toxicity of benzoylurea pesticides, including DFB, to bovine mammary epithelial cells (MAC-T) is unclear. Therefore, in this study, we confirmed the cytotoxic effects of DFB on the viability and proliferation of MAC-T cells. Additionally, we observed that DFB induced lipid peroxidation through reactive oxygen species (ROS) production, resulting in an increase in transcriptional gene expression related to inflammatory response. Moreover, we demonstrated mitochondrial dysfunction including depolarization of the mitochondrial membrane, perturbation of calcium homeostasis, and, eventually, apoptosis. Furthermore, we identified DFB-triggered signaling pathways related to ROS generation and cell proliferation, as well as their interactions, by treating the cells with pharmacological inhibitors in combination with DFB. DFB attenuated the phosphorylation of AKT, P70S6K, S6, and ERK1/2 and facilitated the phosphorylation of JNK and c-Jun. These results show that DFB can induce apoptotic cell death via ROS generation and mitochondrial dysfunction in MAC-T cells.


Assuntos
Diflubenzuron , Animais , Apoptose , Bovinos , Diflubenzuron/metabolismo , Células Epiteliais , Mitocôndrias , Espécies Reativas de Oxigênio/metabolismo
18.
Sensors (Basel) ; 21(9)2021 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-34068761

RESUMO

In the last ten years, supported by the advances in technologies for unmanned aerial vehicles (UAVs), UAVs have developed rapidly and are utilized for a wide range of applications. To operate UAVs safely, by exchanging control packets continuously, operators should be able to monitor UAVs in real-time and deal with any problems immediately. However, due to any networking problems or unstable wireless communications, control packets can be lost or transmissions can be delayed, which causes the unstable drone control. To overcome this limitation, in this paper, we propose MuTran for enabling reliable UAV control. MuTran considers the packet type and duplicates only control packets, not data packets. After that, MuTran transmits the original and duplicate packets through multiple protocols and paths to improve the reliability of control packet transmissions. We designed MuTran and conducted a lot of theoretical analyses to demonstrate the validity of MuTran and analyze it from various aspects. We implemented MuTran on real devices and evaluated MuTran using the devices. We conducted experiments to verify the limitations of the existing systems and demonstrate that control packets can be transmitted more stably by using MuTran. Through the analysis and experimental results, we confirmed that MuTran reduces the control packet transfer delay, which improves the reliability and stability of controlling UAVs.

19.
Sensors (Basel) ; 21(23)2021 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-34884115

RESUMO

Supported by the advances in rocket technology, companies like SpaceX and Amazon competitively have entered the satellite Internet business. These companies said that they could provide Internet service sufficiently to users using their communication resources. However, the Internet service might not be provided in densely populated areas, as the satellites coverage is broad but its resource capacity is limited. To offload the traffic of the densely populated area, we present an adaptable aerial access network (AAN), composed of low-Earth orbit (LEO) satellites and federated reinforcement learning (FRL)-enabled unmanned aerial vehicles (UAVs). Using the proposed system, UAVs could operate with relatively low computation resources than centralized coverage management systems. Furthermore, by utilizing FRL, the system could continuously learn from various environments and perform better with the longer operation times. Based on our proposed design, we implemented FRL, constructed the UAV-aided AAN simulator, and evaluated the proposed system. Base on the evaluation result, we validated that the FRL enabled UAV-aided AAN could operate efficiently in densely populated areas where the satellites cannot provide sufficient Internet services, which improves network performances. In the evaluations, our proposed AAN system provided about 3.25 times more communication resources and had 5.1% lower latency than the satellite-only AAN.

20.
Sensors (Basel) ; 21(8)2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33921044

RESUMO

Recently, unmanned aerial vehicles (UAVs) have been applied to various applications. In order to perform repetitive and accurate tasks with a UAV, it is more efficient for the operator to perform the tasks through an integrated management program rather than controlling the UAVs one by one through a controller. In this environment, control packets must be reliably delivered to the UAV to perform missions stably. However, wireless communication is at risk of packet loss or packet delay. Typical network communications can respond to situations in which packets are lost by retransmitting lost packets. However, in the case of UAV control, delay due to retransmission is fatal, so control packet loss and delay should not occur. As UAVs move quickly, there is a high risk of accidents if control packets are lost or delayed. In order to stably control a UAV by transmitting control messages, we propose a control packet transmission scheme, ConClone. ConClone replicates control packets and then transmits them over multiple network connections to increase the probability of successful control packet transmission. We implemented ConClone using real equipment, and we verified its performance through experiments and theoretical analysis.

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