Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sensors (Basel) ; 24(3)2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38339527

RESUMO

In order to improve the measurement sensitivity of ferrous wear debris sensors with a permanent magnet, a new numerical approach to the appropriate position of the sensor is presented. Moreover, a flow guide wall is proposed as a way to concentrate flow around the ferrous particle sensors. The flow guide wall is intended to further improve measurement sensitivity by allowing the flow containing ferrous particles to flow around the sensor. Numerical analysis was performed using the multi-physics analysis method for the most representative gearbox of the sump-tank type. In condition diagnosis using ferrous wear debris sensors, the position of the sensor has a great influence. In other words, there are cases where no measurements occur, despite the presence of abnormal wear and damage due to the wrong sensor position. To determine the optimal sensor position, this study used flow analysis for the flow caused by the movement of the gear, electric and magnetic field analysis to implement the sensor, and a particle tracing technique to track particle trajectory. The new analysis method and results of this study will provide important information for selecting the optimal sensor location and for the effective application of ferrous wear debris sensors, and will contribute to the oil sensor-based condition diagnosis technology.

2.
Sensors (Basel) ; 23(12)2023 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-37420548

RESUMO

This study aimed to improve the sensitivity of ferrous particle sensors used in various mechanical systems such as engines to detect abnormalities by measuring the number of ferrous wear particles generated by metal-to-metal contact. Existing sensors collect ferrous particles using a permanent magnet. However, their ability to detect abnormalities is limited because they only measure the number of ferrous particles collected on the top of the sensor. This study provides a design strategy to boost the sensitivity of an existing sensor using a multi-physics analysis method, and a practical numerical method was recommended to assess the sensitivity of the enhanced sensor. The sensor's maximum magnetic flux density was increased by around 210% compared to the original sensor by changing the core's form. In addition, in the numerical evaluation of the sensitivity of the sensor, the suggested sensor model has improved sensitivity. This study is important because it offers a numerical model and verification technique that may be used to enhance the functionality of a ferrous particle sensor that uses a permanent magnet.

3.
Materials (Basel) ; 16(10)2023 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-37241362

RESUMO

This study presents the current literature regarding the investigation of varnish contamination among the various types of lubricant contaminations. As the duration of use of lubricants increases, the lubricant deteriorates and may become contaminated. Varnish has been known to cause filter plugging, sticking of the hydraulic valves and fuel injection pumps, flow obstruction, clearance reduction, poor heating and cooling performance, and increased friction and wear in various lubrication systems. These problems may also result in mechanical system failures, performance degradation, and increased maintenance and repair costs. To improve the problems caused by varnish contamination, an adequate understanding of varnish is required. Therefore, in this review, the definitions and characteristics, generating machinery, generating mechanisms, causes, measurement methods, and prevention or removal methods of varnish are summarized. Most of the data presented herein are reports from manufacturers related to lubricants and machine maintenance that are included in published works. We expect that this summary will be helpful to those who are engaged in reducing or preventing varnish-related problems.

4.
Materials (Basel) ; 16(4)2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36837053

RESUMO

This study presents a condition diagnosis system based on a ferrous particle sensor to estimate the durability of axles in construction equipment. Axles are mechanical devices that play the role of the differential gear in construction equipment that move with wheels and require high reliability. In the durability testing of new axles, failure identification and real-time diagnosis are required. One of the typical failure modes of an axle is increased ferrous-wear particles due to metal-to-metal contact. Therefore, a condition diagnostic program based on the ferrous particle sensor is developed and applied in the bench tests of axles. This program provides information on the amount of wear with respect to ferrous particles using a simple diagnostic algorithm. Additionally, it allows separation and storage of measured data that exceed the reference values; the system provides warnings using color, sound, and pop-up windows to facilitate diagnosis. In the two tests, the first case detected a failure, but in the other case, the sensor did not detect it even though a failure occurred. From the results of bench tests, it is confirmed that the sensor location is a critical factor. Therefore, a multi-physics-based analysis method is suggested for positioning the ferrous particle sensor.

5.
Materials (Basel) ; 15(21)2022 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-36363248

RESUMO

In this study, we focus on the correctness of oil condition monitoring, specifically of a tuning forks sensor in hydraulic systems. We also aim to analyze the correlation between the online monitoring sensor signal and offline oil analysis by periodically sampling the hydraulic oil. In recent years, condition-based monitoring (CBM) of hydraulic oils has played a key role in extending earthmoving machinery uptime and reducing maintenance costs. We performed rig test and field test to develop a condition monitoring system based on oil analysis for construction equipment. Using the rig test, a reference line for the diagnosis of viscosity and dielectric constant for the new hydraulic oil was derived, and the characteristics of each sensor parameter for artificial contamination and oxidation were confirmed. In order to affirm the validity of oil diagnosis using oil sensors, the oil sensors were applied to four excavators to detect changes in oil conditions over 12 months. It was found that monitoring hydraulic oil with an oil sensor detecting the change in oil properties and contamination can provide reliable information for establishing diagnostic criteria. The finding allows us to predict the remaining oil life and to determine the oil change intervals based on the diagnosis of the oil condition.

6.
Nutr Res Pract ; 12(5): 387-395, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30323906

RESUMO

BACKGROUND/OBJECTIVES: Recent studies showed vitamin D deficiency is linked to chronic diseases in addition to skeletal metabolism which could threaten the elderly. We analyzed health conditions and socio-demographic factors associated with vitamin D deficiency in community dwelling people aged 65 years and older. SUBJECTS/METHOD: Data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2010 to 2012 were obtained. A total of 2,687 subjects aged 65 years and older were participated. The cutoff value of the Vitamin D deficiency was considered as serum 25-hydroxyvitamin D [25(OH)D] ≤ 20 ng/mL (50 nmol/L). RESULTS: The overall prevalence rate of vitamin D deficiency in the elderly was 62.1%. The factors such as female, obesity, metabolic syndrome, current smoker, and skipping breakfast were positively associated with vitamin D deficiency, but high intensity of physical activity and more than 9 hours of sleep duration were negatively associated with vitamin D deficiency (all P < 0.05). CONCLUSIONS: It is important that health professions know that the factors proved in this study are connected to vitamin D deficiency thus provide information and intervention strategies of vitamin D deficiency to old aged people.

7.
Nicotine Tob Res ; 18(9): 1877-1885, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27611309

RESUMO

INTRODUCTION: Cigarette smoke (CS) is associated with a broad range of diseases including lung cancer. Many researchers have suggested that cigarette smoke condensate (CSC) may be more toxic compared to cigarette smoke extract (CSE) because CSC contains the lipid-soluble faction of smoke while CSE contains the hydrophilic or gas phase. The aim of this research is to investigate the effects of CSC on the disruption of endoplasmic reticulum (ER)-Golgi homeostasis in normal lung epithelial cells. METHODS: CS was generated according to the ISO 3308 method. To ascertain the mechanistic effects of CSC on lung toxicity, normal lung epithelial cells of the cell line 16HBE14o- were treated with CSC (0.1mg/mL) for 48 hours. The toxic effects of CSC on ER-Golgi homeostasis and GOLPH3 expression were observed through diverse molecular tools including transmission electron microscope analysis. RESULTS: Our results demonstrated that CSC treatment increased reactive oxygen species generation in lung cells and led to the alteration of ER-Golgi homeostasis in conjunction with increased autophagy. In particular, GOLPH3, known as an oncogene and a marker protein for the trans-Golgi network, was upregulated in CSC-treated cells. GOLPH3 protein overexpression was also confirmed in the lungs of human lung cancer patients as well as NNK-treated mice. CONCLUSION: Our study revealed that CSC caused lung damage through the disruption of ER-Golgi homeostasis and autophagy induction. The expression level of the trans-Golgi marker protein GOLPH3 could serve as a reliable bio-indicator for CS-related lung cancer. IMPLICATIONS: CS is a harmful factor in the development of many diseases including cancer. In this research, we demonstrated that CSC treatment led to malfunction of the ER-Golgi network, with the disrupted ER and Golgi causing GOLPH3 overexpression and abnormal autophagy accumulation. In addition, although the value of GOLPH3 as a predictor remains to be fully elucidated, our data suggest that GOLPH3 levels may be a novel prognostic biomarker of tobacco related lung disease.


Assuntos
Pulmão/patologia , Proteínas de Membrana/metabolismo , Nicotiana/toxicidade , Fosfoproteínas/metabolismo , Fumar/efeitos adversos , Animais , Carcinógenos/farmacologia , Retículo Endoplasmático/efeitos dos fármacos , Retículo Endoplasmático/metabolismo , Retículo Endoplasmático/patologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Feminino , Complexo de Golgi/efeitos dos fármacos , Complexo de Golgi/metabolismo , Complexo de Golgi/patologia , Humanos , Pulmão/efeitos dos fármacos , Pulmão/metabolismo , Proteínas de Membrana/genética , Camundongos , Modelos Animais , Nitrosaminas/farmacologia , Fosfoproteínas/genética
8.
Appl Microbiol Biotechnol ; 98(3): 1417-27, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23836347

RESUMO

Bacterial community dynamics was examined in an actual biological activated carbon (BAC) process for four consecutive seasons, using quantitative polymerase chain reaction and pyrosequencing. The BAC stably removed organic carbons for the period, although the water temperature substantially varied over the study period. Neither the population density nor community organization was correlated with time and temperature. However, the similarity degree between communities significantly reduced with time and temperature differences. Community analyses indicated that the community evolved over time, resulting in four distinct groups, and that the abundances of particular bacteria were significantly correlated with time and temperature, as well as their interaction. Additionally, backwashing did not affect the BAC bacterial population, community organization (diversity, evenness, and richness), or composition, although backwashing dislodged a large number of bacteria from the BAC (≈10(15) · m(-3)). These results suggest that water temperature is an important factor driving community dynamics and that backwashing is a harmless management option for biomass control.


Assuntos
Bactérias/classificação , Biota , Carvão Vegetal , Microbiologia da Água , Purificação da Água/métodos , Bactérias/genética , Dados de Sequência Molecular , Reação em Cadeia da Polimerase em Tempo Real , Estações do Ano , Análise de Sequência de DNA , Temperatura
9.
Nutr Res Pract ; 7(6): 495-502, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24353836

RESUMO

Recent studies suggest that vitamin D deficiency and cardiometabolic disorders are becoming increasingly more prevalent across multiple populations. However, there is a lack of comprehensive data for Korean adults. We investigated the vitamin D status, the prevalence of vitamin D deficiency and its association with metabolic syndrome (MS) risk in Korean adults aged 20 years or older. The study subjects (n = 18,305) were individuals who participated in the Korean National Health Examination and Nutrition Survey (KNHANES) in 2008-2010. Vitamin D status (25-hydroxyvitamin D [25(OH)D]) was categorized as < 20, 21-29, and ≥ 30 ng/mL, which are the cut-off points for deficiency, insufficiency and normal limits. A wide variety of cardiometabolic risk factors were compared according to the vitamin D status. Vitamin D deficiency was found in 53.9% of men and 70.5% of women. Mean BMI, systolic BP, HbA1c and low density lipoprotein cholesterol (LDL-C) were highest in the vitamin D deficiency group in both genders. Further, the MS was most prevalent in the vitamin D deficiency group in both genders (12.3%, P = 0.002 in men and 9.2%, P < 0.001 in women). Compared to the vitamin D normal group, the adjusted odds ratio (ORs) (95% confidence interval [95% CI]) for MS in the vitamin D deficiency group were 1.46 (1.05-2.02) in men and 1.60 (1.21-2.11) in women, after adjusting for confounding variables. In conclusion, Vitamin D deficiency is a very common health problem in Korean adults and is independently associated with the increasing risk of MS.

10.
Clin J Pain ; 28(7): 635-8, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22699132

RESUMO

INTRODUCTION: With the exception of interdigital neuromas, cutaneous neuromas are relatively rare and often present a diagnostic challenge. CASE REPORT: We describe a case of a 30-year-old man with a 9-month history of intractable pain and touch allodynia on the medial side of his proximal left leg. Although the exact focus of the pain and allodynia was initially difficult to detect, a subsequent thorough physical examination revealed touch allodynia in a 1×1-cm area overlying the proximal tibia, immediately below the left patella. Ultrasonography of this site with a 7.5-MHz linear probe showed a 2×4-mm round hypoechoic mass with smooth margins that was suspected to be a neuroma arising from the infrapatellar branch of the saphenous nerve. An excisional biopsy was then performed, the pathology of which revealed perineurial thickening, inflammatory cells in the perineurium, and neovascularization, consistent with neuroma. All symptoms disappeared immediately after an excisional biopsy. CONCLUSIONS: The diagnosis of cutaneous neuroma should be considered in all patients who have intractable pain and allodynia at unusual locations and in atypical patterns. In addition, ultrasonography can prove very useful in the detection of small cutaneous neuromas if the site of symptoms can be precisely localized.


Assuntos
Hiperalgesia/etiologia , Joelho/fisiopatologia , Neuroma/complicações , Dor/etiologia , Neoplasias Cutâneas/complicações , Adulto , Humanos , Masculino , Nervo Tibial/fisiopatologia
11.
J Hazard Mater ; 165(1-3): 39-47, 2009 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-19059718

RESUMO

Various experiments were conducted to improve durability against SO(2) by impregnating the same amount of vanadium in TiO(2) which had the various physical properties. According to those catalysts, the degree of deactivation by SO(2) had various results, and it was found that the production of unreacted NH(3) in selective catalytic reduction reaction should be low. Based on X-ray photoelectron spectroscopy analysis, O(2) on-off test, O(2) reoxidation test and H(2)-temperature programmed reduction experiment, the redox capacity of catalyst was improved due to increasing of non-stoichiometric compounds. Such a non-stoichiometric oxide and redox capacity of catalyst can be enhanced by the ball-milling process, and the production of ammonium sulfate salt can be more easily inhibited by the superior oxidation-reduction capacity of catalyst. We found that this result is caused by producing and increasing of V(x+) (x

Assuntos
Titânio/química , Vanádio/química , Amônia , Catálise , Oxirredução , Dióxido de Enxofre
12.
Bioorg Med Chem ; 16(5): 2570-8, 2008 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-18083580

RESUMO

5-HT(7) receptor antagonists generated antidepressant-like effects in animal model and the involvement of the 5-HT(7) receptor in other pathophysiological mechanisms such as thermoregulation, learning and memory, and sleep has been highlighted by various studies. As one of our efforts to discover a new type of 5-HT(7) receptor antagonists, we here report on the synthesis and binding affinities to the 5-HT(7) receptor of the quinazolinone library 1, which was designed with various substituents (X, Y, R(1), and R(2)) on the aromatic rings and different carbon chain length. Total 85 compounds of the quinazolinone library 1 were synthesized and the binding affinities of all the synthesized compounds were obtained by radioligand binding assay for the 5-HT(7) receptor. Among the 85 compounds, 24 compounds show very good binding affinities with IC(50) values below 100 nM. Mainly the compounds with IC(50) values below 100 nM have o-OMe or o-OEt as R(2) substituent. The compound with the best binding affinity is 1-68 of which the IC(50) value is 12 nM. In in vivo animal study, some synthesized compounds really have the antidepressant activity in the forced swimming test in mice.


Assuntos
Quinazolinonas/síntese química , Receptores de Serotonina/química , Receptores de Serotonina/metabolismo , Animais , Antidepressivos/síntese química , Antidepressivos/química , Antidepressivos/uso terapêutico , Depressão/tratamento farmacológico , Ligantes , Camundongos , Estrutura Molecular , Neurotransmissores/síntese química , Neurotransmissores/química , Quinazolinonas/química , Quinazolinonas/uso terapêutico , Antagonistas da Serotonina/síntese química , Antagonistas da Serotonina/química , Antagonistas da Serotonina/farmacologia , Relação Estrutura-Atividade , Natação
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...