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1.
ACS Nano ; 2021 Jan 28.
Artigo em Inglês | MEDLINE | ID: mdl-33506675

RESUMO

The structures as building blocks for designing functional nanomaterials have fueled the development of versatile nanoprobes to understand local structures of noncrystalline specimens. Progress in analyzing structures of individual specimens with atomic scale accuracy has been notable recently. In most cases, however, only a limited number of specimens are inspected lacking statistics to represent the systems with structural inhomogeneity. Here, by employing single-particle imaging with X-ray free electron lasers and algorithms for multiple-model 3D imaging, we succeeded in investigating several thousand specimens in a couple of hours and identified intrinsic heterogeneities with 3D structures. Quantitative analysis has unveiled 3D morphology, facet indices, and elastic strain. The 3D elastic energy distribution is further corroborated by molecular dynamics simulations to gain mechanical insight at the atomic level. This work establishes a route to high-throughput characterization of individual specimens in large ensembles, hence overcoming statistical deficiency while providing quantitative information at the nanoscale.

2.
J Clin Pediatr Dent ; 44(6): 451-458, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-33378466

RESUMO

OBJECTIVE: The surface roughness of various orthodontic materials could affect biofilm formation and friction. The purpose of this study was to examine the surface roughness and chemical composition of the slots and wings of several ceramic self-ligating brackets. STUDY DESIGN: Four types of ceramic self-ligating brackets were separated into experimental groups (DC, EC, IC, and QK) while a metal self-ligating bracket (EM) was used as the control group. Atomic force microscopy and energy-dispersive x-ray spectroscope were used to examine the surface roughness and chemical composition of each bracket slot and wing. RESULTS: The control group was made of ferrum and chrome while all the experimental groups were comprised of aluminum and oxide. There was a statistically significant difference in the roughness average (Sa) among the various self-ligating brackets (p< 0.001 in slots and p<0.01 in the wing). The slots in the EC group had the lowest Sa, followed by the DC, IC, control, and QK groups. The wings in the IC group had the lowest Sa, followed by the EC, DC, control, and QK groups. CONCLUSIONS: There is a significant difference in the surface roughness of the slots and wings among several types of ceramic self-ligating brackets.


Assuntos
Braquetes Ortodônticos , Biofilmes , Cerâmica , Ligas Dentárias , Fricção , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Fios Ortodônticos , Aço Inoxidável , Propriedades de Superfície
3.
Rev Sci Instrum ; 91(8): 083904, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32872965

RESUMO

Resonant elastic x-ray scattering has been widely employed for exploring complex electronic ordering phenomena, such as charge, spin, and orbital order, in particular, in strongly correlated electronic systems. In addition, recent developments in pump-probe x-ray scattering allow us to expand the investigation of the temporal dynamics of such orders. Here, we introduce a new time-resolved Resonant Soft X-ray Scattering (tr-RSXS) endstation developed at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). This endstation has an optical laser (wavelength of 800 nm plus harmonics) as the pump source. Based on the commissioning results, the tr-RSXS at PAL-XFEL can deliver a soft x-ray probe (400 eV-1300 eV) with a time resolution of ∼100 fs without jitter correction. As an example, the temporal dynamics of a charge density wave on a high-temperature cuprate superconductor is demonstrated.

4.
J Ginseng Res ; 44(5): 738-746, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32913403

RESUMO

Background: Red ginseng contains components, including microelements, vitamins, essential oils, and fatty acids, that can be used in skincare to delay the aging process. We investigated the effects of red ginseng treatment on skin elasticity by assessing cellular stiffness and measuring collagen protein synthesis. Methods: Human dermal fibroblasts were treated with red ginseng, and the resulting changes in stiffness were investigated using atomic force microscopy. Cytoskeletal changes and mRNA expression of biomarkers of aging, including that of procollagens I and VII, elastin, and fibrillin-1, were investigated. Collagen in a human skin equivalent treated with red ginseng was visualized via hematoxylin and eosin staining, scanning electron microscopy, and atomic force microscopy. Results and conclusion: The stiffness of fibroblasts was significantly reduced by treatment with red ginseng concentrations of ≥ 0.8 mg/mL. The ratio of F-actin to G-actin decreased after treatment, which corresponded to a change in fibroblast stiffness. The storage modulus (G') and loss modulus (G″) of the skin equivalent were both lowered by red ginseng treatment. This result indicates that the viscoelasticity of the skin equivalent can be restored by red ginseng treatment.

5.
J Cancer ; 11(18): 5403-5412, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32742487

RESUMO

Lower cellular elasticity is a distinguishing feature of cancer cells compared with normal cells. To determine whether cellular elasticity differs based on cancer cell type, cells were selected from three different cancer types including breast, cervix, and lung. For each cancer type, one counterpart normal cell and three types of cancer cells were selected, and their elasticity was measured using atomic force microscopy (AFM). The elasticity of normal cells was in the order of MCF10A > WI-38 ≥ Ect1/E6E7 which corresponds to the counterpart normal breast, lung, and cervical cancer cells, respectively. All cancer cells exhibited lower elasticity than their counterpart normal cells. Compared with the counterpart normal cells, the difference in cellular elasticity was the greatest in cervical cancer cells, followed by lung and breast cancer cells. This result indicates lower elasticity is a unique property of cancer cells; however, the reduction in elasticity may depend on the histological origin of the cells. The F-actin cytoskeleton of cancer cells was different in structure and content from normal cells. The F-actin is mainly distributed at the periphery of cancer cells and its content was mostly lower than that seen in normal cells.

6.
J Am Chem Soc ; 142(33): 14249-14266, 2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32683863

RESUMO

Soluble methane monooxygenase (sMMO) is a multicomponent metalloenzyme that catalyzes the conversion of methane to methanol at ambient temperature using a nonheme, oxygen-bridged dinuclear iron cluster in the active site. Structural changes in the hydroxylase component (sMMOH) containing the diiron cluster caused by complex formation with a regulatory component (MMOB) and by iron reduction are important for the regulation of O2 activation and substrate hydroxylation. Structural studies of metalloenzymes using traditional synchrotron-based X-ray crystallography are often complicated by partial X-ray-induced photoreduction of the metal center, thereby obviating determination of the structure of the enzyme in pure oxidation states. Here, microcrystals of the sMMOH:MMOB complex from Methylosinus trichosporium OB3b were serially exposed to X-ray free electron laser (XFEL) pulses, where the ≤35 fs duration of exposure of an individual crystal yields diffraction data before photoreduction-induced structural changes can manifest. Merging diffraction patterns obtained from thousands of crystals generates radiation damage-free, 1.95 Å resolution crystal structures for the fully oxidized and fully reduced states of the sMMOH:MMOB complex for the first time. The results provide new insight into the manner by which the diiron cluster and the active site environment are reorganized by the regulatory protein component in order to enhance the steps of oxygen activation and methane oxidation. This study also emphasizes the value of XFEL and serial femtosecond crystallography (SFX) methods for investigating the structures of metalloenzymes with radiation sensitive metal active sites.

7.
Cancer Cell Int ; 20: 217, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32518526

RESUMO

Background: Because cell movement is primarily driven by the connection between F-actin and integrin through a physical linkage, cellular elasticity and adhesion strength have been considered as biomarkers of cell motility. However, a consistent set of biomarkers that indicate the potential for cell motility is still lacking. Methods: In this work, we characterize a phenotype of cell migration in terms of cellular elasticity and adhesion strength, which reveals the interdependence of subcellular systems that mediate optimal cell migration. Results: Stiff cells weakly adhered to the substrate revealed superior motility, while soft cell migration with strong adhesion was relatively inhibited. The spatial distribution and amount of F-actin and integrin were highly variable depending on cell type, but their density exhibited linear correlations with cellular elasticity and adhesion strength, respectively. Conclusions: The densities of F-actin and integrin exhibited linear correlations with cellular elasticity and adhesion strength, respectively, therefore, they can be considered as biomarkers to quantify cell migration characteristics.

8.
Skin Res Technol ; 26(6): 914-922, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32594564

RESUMO

PURPOSE: An electric field (EF) can be used to change the mechanical properties of cells and skin tissues. We demonstrate EF-induced elasticity changes in human dermal fibroblasts (HDFs) and a human skin equivalent and identify the underlying principles related to the changes. METHODS: HDFs and human skin equivalent were stimulated with electric fields of 1.0 V/cm. Change in cellular elasticity was determined by using atomic force microscopy. Effects of EF on the biomechanical and chemical properties of a human skin equivalent were analyzed. In cells and tissues, the effects of EF on biomarkers of cellular elasticity were investigated at the gene and protein levels. RESULTS: In HDFs, the cellular elasticity was increased and the expression of biomarkers of cellular elasticity was regulated by the EF. Expression of the collagen protein in the human skin equivalent was changed by EF stimulation; however, changes in density and microstructure of the collagen fibrils were not significant. The viscoelasticity of the human skin equivalent increased in response to EF stimulation, but molecular changes were not observed in collagen. CONCLUSIONS: Elasticity of cells and human skin equivalent can be regulated by electrical stimulation. Especially, the change in cellular elasticity was dependent on cell age.

9.
Sci Rep ; 10(1): 7993, 2020 05 14.
Artigo em Inglês | MEDLINE | ID: mdl-32409692

RESUMO

Although uterine leiomyomas are the most common benign uterine tumors in women, there is no effective therapy that can also preserve the uterus and maintain fertility. The work aimed to work was to discover a potential natural agent that has pharmacological activities on uterine leiomyomas with fewer adverse effects. We chose Rhus verniciflua Stokes (RVS) as a candidate after primary cytotoxicity testing, and analyzed the RVS components that showed pharmacological activity. Leiomyoma cells and myometrium cells were cultured from uterine tissues obtained from patients, and were treated with RVS at varying concentrations. RVS was cytotoxic in both leiomyoma and myometrium cells; however, the effects were more prominent in the leiomyoma cells. Among the bioactive components of RVS, fisetin showed significant pharmacological effects on leiomyoma cells. Fisetin showed excellent leiomyoma cell cytotoxicity and induced apoptotic cell death with cell cycle arrest. The apoptotic cell death appeared to involve not one specific pathway but multichannel pathways (intrinsic, extrinsic, MARK, and p53-mediated pathways), and autophagy. The multichannel apoptosis pathways were activated with a low concentration of fisetin (IC50). This is the first demonstration to show the pharmacological activities of fisetin on leiomyoma cells. These findings suggest that fisetin may be used for the prevention and treatment of uterine leiomyomas. Since fisetin can be obtained from plants, it may be a safe and effective alternative treatment for uterine leiomyomas.

10.
Sci Adv ; 6(3): eaax2445, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-32010766

RESUMO

Melting is a fundamental process of matter that is still not fully understood at the microscopic level. Here, we use time-resolved x-ray diffraction to examine the ultrafast melting of polycrystalline gold thin films using an optical laser pump followed by a delayed hard x-ray probe pulse. We observe the formation of an intermediate new diffraction peak, which we attribute to material trapped between the solid and melted states, that forms 50 ps after laser excitation and persists beyond 500 ps. The peak width grows rapidly for 50 ps and then narrows distinctly at longer time scales. We attribute this to a melting band originating from the grain boundaries and propagating into the grains. Our observation of this intermediate state has implications for the use of ultrafast lasers for ablation during pulsed laser deposition.

11.
J Cosmet Dermatol ; 19(5): 1211-1218, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31509335

RESUMO

BACKGROUND: Transforming growth factor-ß (TGF-ß) is a major regulator of extracellular matrix (ECM) events, particularly collagen production. AIM: We explored whether the expression of matrix metalloproteinases (MMPs) and collagen are transcriptionally regulated by the TGF-ß and Smad signaling pathways, and the roles played by NF-κB and mitogen-activated protein kinase (MAPK) signaling in normal, aged, human dermal fibroblasts. METHODS: We quantified mRNA and protein expression using real-time PCR and immunoblotting of proteins from cells in passage 5-15. RESULTS: The levels of mRNAs encoding TGF-ß1, TGF-ß3, and TGF-ß receptor type I (TGFß RI) decreased with increasing passage number. The levels of mRNAs encoding TGF-ß2, TGFß RII, and TGFß RIII increased to passage 10 but decreased by passage 15. The levels of mRNAs encoding Smad-2, -3, -4, and -7 decreased with increasing passage number. The level of mRNA encoding MMP-1 increased with increasing passage number, and the levels of mRNAs encoding MMP-2, TIMP-1, and TIMP-2 increased to passage 10 but decreased by passage 15. The levels of mRNAs encoding collagen types I and II decreased with increasing passage number. At the protein level, NF-κB, IκBα, p38, ERK, Akt, and JNK became increasingly phosphorylated at higher passage numbers. CONCLUSION: Our results suggest that reductions in the expression levels of MMPs and collagen types I and III in aging human dermal fibroblasts reflect reduced expression of TGF-ß/Smad and TGF-ß receptors, thus compromising the TGF-ß receptor-binding capacity of fibroblasts; the NF-κB and Akt-JNK/MAPK signaling pathways may play active roles in this process.

12.
Cell Mol Life Sci ; 77(7): 1345-1355, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31605149

RESUMO

Cells are dynamic structures that continually generate and sustain mechanical forces within their environments. Cells respond to mechanical forces by changing their shape, moving, and differentiating. These reactions are caused by intracellular skeletal changes, which induce changes in cellular mechanical properties such as stiffness, elasticity, viscoelasticity, and adhesiveness. Interdisciplinary research combining molecular biology with physics and mechanical engineering has been conducted to characterize cellular mechanical properties and understand the fundamental mechanisms of mechanotransduction. In this review, we focus on the role of cytoskeletal proteins in cellular mechanics. The specific role of each cytoskeletal protein, including actin, intermediate filaments, and microtubules, on cellular elasticity is summarized along with the effects of interactions between the fibers.


Assuntos
Osso e Ossos/fisiologia , Elasticidade , Espaço Intracelular/fisiologia , Citoesqueleto de Actina/metabolismo , Animais , Humanos , Proteínas dos Microfilamentos/metabolismo , Microtúbulos/metabolismo
13.
Food Chem Toxicol ; 136: 111011, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31790773

RESUMO

Neurite outgrowth is important process in synaptic formation and neuronal development. Many previous studies reported that natural compounds as well as neurotrophins induce neurite outgrowth through various signaling pathways. In this study, we tested the effect of cryptotanshinone (CPT), a constituent of Salvia miltiorrhiza Bunge, on neurite outgrowth using neuro2a cell line, a mouse neuroblastoma cell line. And then, we examined the effect of CPT on learning and memory. We first found that CPT facilitated neurite outgrowth in a concentration-dependent manner. Although CPT induced MTT reduction, CPT did not induce LDH release. Moreover, CPT suppressed cell proliferation. CPT increased ERK1/2 phosphorylation and ERK1/2 inhibitor blocked CPT-facilitated neurite outgrowth. CPT also enhanced learning and memory without affecting basal sensory conditions and increased ERK1/2 phosphorylation in the hippocampus in a dose-dependent manner. These results demonstrate that CPT facilitates neurite outgrowth and enhances learning and memory, which may be mediated by facilitating ERK1/2 signal.


Assuntos
Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Memória/efeitos dos fármacos , Crescimento Neuronal/efeitos dos fármacos , Fenantrenos/farmacologia , Animais , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Feminino , Hipocampo/metabolismo , Aprendizagem/efeitos dos fármacos , Masculino , Camundongos , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fosforilação/efeitos dos fármacos
14.
J Synchrotron Radiat ; 27(Pt 1): 17-24, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31868731

RESUMO

With each single X-ray pulse having its own characteristics, understanding the individual property of each X-ray free-electron laser (XFEL) pulse is essential for its applications in probing and manipulating specimens as well as in diagnosing the lasing performance. Intensive research using XFEL radiation over the last several years has introduced techniques to characterize the femtosecond XFEL pulses, but a simple characterization scheme, while not requiring ad hoc assumptions, to address multiple aspects of XFEL radiation via a single data collection process is scant. Here, it is shown that single-particle diffraction patterns collected using single XFEL pulses can provide information about the incident photon flux and coherence property simultaneously, and the X-ray beam profile is inferred. The proposed scheme is highly adaptable to most experimental configurations, and will become an essential approach to understanding single X-ray pulses.

15.
Neurochem Int ; 131: 104579, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31614166

RESUMO

Neurite outgrowth is the differentiation process by which neurons establish synapses. In the dentate gyrus of the hippocampus, new neurons are constantly produced and undergo neurite outgrowth to form synapses, and this process is involved in cognitive ability. Therefore, if an agent could modulate neurite outgrowth, it could potentially be developed as a compound for modulating cognitive ability. In this study, we examined whether coniferaldehyde, a natural compound, regulates neurite outgrowth in Neuro2a cells. We ascertained morphological changes and measured the percentage of neurite-bearing cells and neurite lengths. Coniferaldehyde significantly increased the percentage of neurite-bearing cells, and the length of neurites in a concentration-dependent manner, without inducing cell death. We then have identified that, coniferaldehyde activates the extracellular signals-regulated Kinase 1 and 2 (ERK1/2), and further noted that, U0126, an ERK1/2 inhibitor, blocks coniferaldehyde-facilitated neurite outgrowth. Moreover, Subchronic administration of CA enhanced learning and memory, and increased neurite length of newborn neurons in the hippocampus. These results suggest that coniferaldehyde induces neurite outgrowth by a process possibly mediated by ERK1/2 signaling and enhances learning and memory.


Assuntos
Acroleína/análogos & derivados , Inibidores Enzimáticos/farmacologia , Neuritos/efeitos dos fármacos , Neuroblastoma/tratamento farmacológico , Acroleína/farmacologia , Animais , Aprendizagem da Esquiva/efeitos dos fármacos , Butadienos/farmacologia , Linhagem Celular Tumoral , Giro Denteado/efeitos dos fármacos , Giro Denteado/patologia , Aprendizagem/efeitos dos fármacos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Memória/efeitos dos fármacos , Camundongos , Neuritos/patologia , Neuroblastoma/patologia , Nitrilos/farmacologia , Nootrópicos/farmacologia , Sinapses/efeitos dos fármacos
16.
Sci Rep ; 9(1): 13400, 2019 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-31527659

RESUMO

Non-thermal atmospheric pressure (NAP) plasma has demonstrated potential in biomedical applications, such as cancer treatment, bactericidal sterilization, and cell growth promotion or inhibition. In this study, for the first time, we demonstrated on-off switching of cell cycle progression and regulated melanogenesis in normal human skin melanocytes by NAP plasma-activated medium (PAM). The melanocytes were exposed to NAP plasma at durations varying from 0 to 20 min, and the effects of PAM on cell proliferation, cell cycle progression, and melanogenesis were investigated. Although PAM showed no cytotoxicity, the proliferation of melanocytes was inhibited. The melanocyte cell cycle was arrested by PAM for a relatively short period (48 h), after which it recovered slowly. PAM promoted melanogenesis through the activation of the enzymes tyrosinase, tyrosinase-related protein-1, and tyrosinase-related protein-2. These effects seem to be related to reactive oxygen species induced by PAM. Our finding that PAM modulates the cell cycle may provide insight into the recurrence of cancer. The regulation of the melanogenesis of melanocytes may facilitate the control of skin tone without incurring negative side effects.


Assuntos
Ciclo Celular , Melaninas/metabolismo , Melanócitos/citologia , Gases em Plasma/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Pele/citologia , Pressão Atmosférica , Sobrevivência Celular , Células Cultivadas , Humanos , Melanócitos/efeitos dos fármacos , Pele/efeitos dos fármacos , Temperatura
17.
Cell Death Dis ; 10(7): 519, 2019 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-31285435

RESUMO

Noxa, a Bcl-2 homology 3 (BH3)-only protein of the Bcl-2 family, is responsive to cell stresses and triggers apoptosis by binding the prosurvival Bcl-2-like proteins Mcl1, BclXL, and Bcl2A1. Although the Noxa BH3 domain is necessary to induce apoptosis, the mitochondrial targeting domain (MTD) of Noxa functions as a pronecrotic domain, an inducer of mitochondrial fragmentation, and delivery to mitochondria. In this study, we demonstrate that the extended MTD (eMTD) peptide induces necrotic cell death by interaction with the VDAC2 protein. The eMTD peptide penetrates the cell membrane, causing cell membrane blebbing, cytosolic calcium influx, and mitochondrial swelling, fragmentation, and ROS generation. The MTD domain binds VDACs and opens the mitochondrial permeability transition pore (mPTP) in a CypD-independent manner. The opening of mPTP induced by eMTD is inhibited either by down-regulation of VDAC2 or by the VDACs inhibitor DIDS. These results indicate that the MTD domain of Noxa causes mitochondrial damage by opening mPTP through VDACs, especially VDAC2, during necrotic cell death.


Assuntos
Mitocôndrias/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/química , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Canal de Ânion 2 Dependente de Voltagem/metabolismo , Sequência de Aminoácidos , Animais , Cálcio/metabolismo , Membrana Celular/metabolismo , Citosol/metabolismo , Células HEK293 , Células HeLa , Humanos , Camundongos Endogâmicos BALB C , Mitocôndrias/ultraestrutura , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Dilatação Mitocondrial , Necrose , Ligação Proteica , Domínios Proteicos , Espécies Reativas de Oxigênio/metabolismo , Relação Estrutura-Atividade
18.
J Mol Endocrinol ; 63(1): 27-38, 2019 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-31075756

RESUMO

Atherosclerosis is the most common root cause of arterial disease, such as coronary artery disease and carotid artery disease. Hypoxia is associated with the formation of macrophages and increased inflammation and is known to be present in lesions of atherosclerotic. Vascular smooth muscle cells (VSMCs) are one of the major components of blood vessels, and hypoxic conditions affect VSMC inflammation, proliferation and migration, which contribute to vascular stenosis and play a major role in the atherosclerotic process. Estrogen receptor (ER)-ß is thought to play an important role in preventing the inflammatory response in VSMCs. In this report, we studied the anti-inflammatory effect of indazole (In)-Cl, an ERß-specific agonist, under conditions of hypoxia. Expression of cyclooxygenase-2 reduced by hypoxia was inhibited by In-Cl treatment in VSMCs, and this effect was antagonized by an anti-estrogen compound. Additionally, the production of reactive oxygen species induced under conditions of hypoxia was reduced by treatment with In-Cl. Increased cell migration and invasion by hypoxia were also dramatically decreased following treatment with In-Cl. The increase in cell proliferation following treatment with platelet-derived growth factor was attenuated by In-Cl in VSMCs. RNA sequencing analysis was performed to identify changes in inflammation-related genes following In-Cl treatment in the hypoxic state. Our results suggest that ERß is a potential therapeutic target for the suppression of hypoxia-induced inflammation in VSMCs.


Assuntos
Ciclo-Oxigenase 2/metabolismo , Hipóxia/complicações , Indazóis/farmacologia , Músculo Liso Vascular/efeitos dos fármacos , Músculo Liso Vascular/metabolismo , Animais , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Receptor beta de Estrogênio/metabolismo , Citometria de Fluxo , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de RNA
19.
PLoS One ; 14(5): e0215890, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31048921

RESUMO

In recent years, safety issues surrounding robots have increased in importance, as more robots are in close contact with humans, both in industrial fields and elsewhere. Safety standards for industrial robots operating in specific spaces have been established, but no such standards have been specified for collaborative and service robots. To establish safety standards for such robots, we assessed pressure pain thresholds for collisions between humans and robots, under the assumption that the pain threshold is lower than the mild injury threshold. The pressure pain threshold for collision with a robot was measured in 90 male Korean adults using a homemade collision system. The pain thresholds were measured three times at 15 sites, including the forehead. The highest threshold was 196.1 ± 85.8 N/cm2 at the back of the hand, and the lowest was 65.1 ± 22.6 N/cm2 at an arm nerve. Moderate thresholds, i.e., 100-120 N/cm2, were noted on the forehead, neck muscle, ball of the thumb, and shin. The thresholds of participants < 30 years of age were lower, by 3-33%, than those of participants aged > 30 years. Thresholds differed by body mass index only at certain sites, including the shoulder joint, neck, and back of the hand. The pressure pain threshold depended on individual characteristics, body site, and age. The threshold relevant to potential human-robot collisions was determined to be between 65.1 ± 22.6 and 196.1 ± 85.8 N/cm2.


Assuntos
Limiar da Dor , Pressão , Robótica , Segurança , Adulto , Índice de Massa Corporal , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
20.
J Cell Physiol ; 234(11): 20546-20553, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-30989677

RESUMO

Malaria is a pathogenic disease in mammal species and typically causes destruction of red blood cells (RBCs). The malaria-infected RBCs undergoes alterations in morphology and its rheological properties, and the altered rheological properties of RBCs have a significant impact on disease pathophysiology. In this study, we investigated detailed topological and biomechanical properties of RBCs infected with malaria Plasmodium berghei ANKA using atomic force microscopy. Mouse (BALB/c) RBCs were obtained on Days 4, 10, and 14 after infection. We found that malaria-infected RBCs changed significantly in shape. The RBCs maintained a biconcave disk shape until Day 4 after infection and then became lopsided on Day 7 after infection. The central region of RBCs began to swell beginning on Day 10 after infection. More schizont stages were present on Days 10 and 14 compared with on Day 4. The malaria-infected RBCs also showed changes in mechanical properties and the cytoskeleton. The stiffness of infected RBCs increased 4.4-4.6-fold and their cytoskeletal F-actin level increased 18.99-67.85% compared with the control cells. The increase in F-actin depending on infection time was in good agreement with the increased stiffness of infected RBCs. Because more schizont stages were found at a late period of infection at Days 10 and 14, the significant changes in biomechanical properties might contribute to the destruction of RBCs, possibly resulting in the release of merozoites into the blood circulation.


Assuntos
Eritrócitos/fisiologia , Eritrócitos/parasitologia , Malária/veterinária , Plasmodium berghei/fisiologia , Animais , Fenômenos Biomecânicos , Citoesqueleto , Malária/sangue , Malária/parasitologia , Camundongos , Camundongos Endogâmicos BALB C
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