306 research outputs found

    In-Situ Mechanical Property Evaluation of Dielectric Ceramics in Multilayer Capacitors

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    The Young's modulus, hardness, and fracture toughness of barium titanate dielectric ceramics in three commercially available multilayer capacitors (MLCs) were measured in-situ using indentation and a mechanical properties microprobe. The three MLCs were equivalent in size (0805), capacitance (0.1 uF) and dielectric type (X7R). The Young's modulus and hardness of the dielectric ceramics in the three MLCs were similar, while there were statistically significant differences in their fracture toughnesses. The results provide insight into the assessment of MLC mechanical reliability, and show that equivalent electrical MLC rating is not necessarily a guarantee that the dielectric ceramics in them will exhibit equivalent mechanical performance

    ΠœΠΎΠ΄Π΅Ρ€Π½ΠΈΠ·Π°Ρ†ΠΈΡ конструкции биологичСского Π»Π°Π±ΠΎΡ€Π°Ρ‚ΠΎΡ€Π½ΠΎΠ³ΠΎ комплСкса

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    ΠžΠ±ΡŠΠ΅ΠΊΡ‚ΠΎΠΌ ΠΌΠΎΠ΄Π΅Ρ€Π½ΠΈΠ·Π°Ρ†ΠΈΠΈ Π² Π΄Π°Π½Π½ΠΎΠΉ Ρ€Π°Π±ΠΎΡ‚Π΅ являСтся конструкция биологичСского Π»Π°Π±ΠΎΡ€Π°Ρ‚ΠΎΡ€Π½ΠΎΠ³ΠΎ комплСкса. ЦСль: модСрнизация конструкции биологичСского Π»Π°Π±ΠΎΡ€Π°Ρ‚ΠΎΡ€Π½ΠΎΠ³ΠΎ комплСкса. Π Π΅Π·ΡƒΠ»ΡŒΡ‚Π°Ρ‚ΠΎΠΌ процСсса ΠΌΠΎΠ΄Π΅Ρ€Π½ΠΈΠ·Π°Ρ†ΠΈΠΈ являСтся конструкция комплСкса Π² CAD систСмС SolidWorks. Π’ Ρ…ΠΎΠ΄Π΅ Ρ€Π°Π±ΠΎΡ‚Ρ‹: ΠΌΠΎΠ΄Π΅Ρ€Π½ΠΈΠ·ΠΈΡ€ΠΎΠ²Π°Π½Π° конструкция комплСкса ΠΏΠΎΠ΄ Π·Π°Π΄Π°Π½Π½Ρ‹Π΅ характСристики, Ρ€Π°Π·Ρ€Π°Π±ΠΎΡ‚Π°Π½ сборочный Ρ‡Π΅Ρ€Ρ‚Π΅ΠΆ, спроСктирован тСхнологичСский процСсс изготовлСния Π΄Π΅Ρ‚Π°Π»ΠΈ Ρ‚ΠΈΠΏΠ° Ρ„Π»Π°Π½Π΅Ρ†.The object of modernization in this work is the construction of a biological laboratory complex. Purpose: modernization of the biological laboratory complex. The result of the modernization process is the design of the complex in the CAD system SolidWorks. In the course of work: the design of the complex has been modernized for the given characteristics, an assembly drawing has been developed, a technological process has been designed for manufacturing a flange type part

    An Experimental and Numerical Investigation of Flapping-Wing Propulsion

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    AIAA Paper No. 99-0995, 37th AIAA Aerospace Sciences Meeting, Reno, Nevada, Jan. 1999.Flapping-wing propulsion is investigated experimentally and numerically with direct comparisons between experimental and numerical thrust measurements for several geometrically simple configurations. Numerical simulations are performed using linear theory, and a previously developed, unsteady panel method that models one or two independently moving airfoils with three-degrees of freedom and non-linear deforming wakes. Experiments are carried out in the Naval Postgraduate School 5'Γ—5' low-speed tunnel. A flapping mechanism that approximates the two-dimensional motions modeled by the panel code is suspended with cables in the wind tunnel, and thrust measurements are made by measuring the streamwise displacement of the model using a laser range-finder. The experimental flapping mechanism utilizes variable aspect-ratio wings and optional tip plates to investigate the effect of three-dimensionality. The device flaps two airfoils, each with two degrees of freedom and adjustable pitch and plunge amplitudes, and additional stationary wings may be attached up and/or downstream of the flapping wings to investigate interference effects

    Electrochemical and antimicrobial properties of diamond like carbon-metal composite films

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    ABSTRACT Implants containing antimicrobial metals may reduce morbidity, mortality, and healthcare costs associated with medical device-related infections. We have deposited diamondlike carbonsilver (DLC-Ag), diamondlike carbon-platinum (DLC-Pt), and diamondlike carbon-silverplatinum (DLC-AgPt) thin films using a multicomponent target pulsed laser deposition process. Transmission electron microscopy of the DLC-silver and DLC-platinum composite films revealed that the silver and platinum self-assemble into nanoparticle arrays within the diamondlike carbon matrix. The diamondlike carbon-silver film possesses hardness and Young's modulus values of 37 GPa and 331 GPa, respectively. The diamondlike carbon-metal composite films exhibited passive behavior at open-circuit potentials. Low corrosion rates were observed during testing in a phosphate-buffered saline (PBS) electrolyte. In addition, the diamondlike carbon-metal composite films were found to be immune to localized corrosion below 1000 mV (SCE). DLC-silver-platinum films demonstrated exceptional antimicrobial properties against Staphylococcus bacteria. It is believed that a galvanic couple forms between platinum and silver, which accelerates silver ion release and provides more robust antimicrobial activity. Diamondlike carbon-silver-platinum films may provide unique biological functionalities and improved lifetimes for cardiovascular, orthopaedic, biosensor, and implantable microelectromechanical systems

    Identification of glucocorticoid-related molecular signature by whole blood methylome analysis

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    Objective Cushing's syndrome represents a state of excessive glucocorticoids related to glucocorticoid treatments or to endogenous hypercortisolism. Cushing's syndrome is associated with high morbidity, with significant inter-individual variability. Likewise, adrenal insufficiency is a life-threatening condition of cortisol deprivation. Currently, hormone assays contribute to identify Cushing's syndrome or adrenal insufficiency. However, no biomarker directly quantifies the biological glucocorticoid action. The aim of this study was to identify such markers. Design We evaluated whole blood DNA methylome in 94 samples obtained from patients with different glucocorticoid states (Cushing's syndrome, eucortisolism, adrenal insufficiency). We used an independent cohort of 91 samples for validation. Methods Leukocyte DNA was obtained from whole blood samples. Methylome was determined using the Illumina methylation chip array (~850 000 CpG sites). Both unsupervised (principal component analysis) and supervised (Limma) methods were used to explore methylome profiles. A Lasso-penalized regression was used to select optimal discriminating features. Results Whole blood methylation profile was able to discriminate samples by their glucocorticoid status: glucocorticoid excess was associated with DNA hypomethylation, recovering within months after Cushing's syndrome correction. In Cushing's syndrome, an enrichment in hypomethylated CpG sites was observed in the region of FKBP5 gene locus. A methylation predictor of glucocorticoid excess was built on a training cohort and validated on two independent cohorts. Potential CpG sites associated with the risk for specific complications, such as glucocorticoid-related hypertension or osteoporosis, were identified, needing now to be confirmed on independent cohorts. Conclusions Whole blood DNA methylome is dynamically impacted by glucocorticoids. This biomarker could contribute to better assessment of glucocorticoid action beyond hormone assays

    Steroid metabolome analysis reveals prevalent glucocorticoid excess in primary aldosteronism

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    BACKGROUND. Adrenal aldosterone excess is the most common cause of secondary hypertension and is associated with increased cardiovascular morbidity. However, adverse metabolic risk in primary aldosteronism extends beyond hypertension, with increased rates of insulin resistance, type 2 diabetes, and osteoporosis, which cannot be easily explained by aldosterone excess. METHODS. We performed mass spectrometry–based analysis of a 24-hour urine steroid metabolome in 174 newly diagnosed patients with primary aldosteronism (103 unilateral adenomas, 71 bilateral adrenal hyperplasias) in comparison to 162 healthy controls, 56 patients with endocrine inactive adrenal adenoma, 104 patients with mild subclinical, and 47 with clinically overt adrenal cortisol excess. We also analyzed the expression of cortisol-producing CYP11B1 and aldosterone-producing CYP11B2 enzymes in adenoma tissue from 57 patients with aldosterone-producing adenoma, employing immunohistochemistry with digital image analysis. RESULTS. Primary aldosteronism patients had significantly increased cortisol and total glucocorticoid metabolite excretion (all P < 0.001), only exceeded by glucocorticoid output in patients with clinically overt adrenal Cushing syndrome. Several surrogate parameters of metabolic risk correlated significantly with glucocorticoid but not mineralocorticoid output. Intratumoral CYP11B1 expression was significantly associated with the corresponding in vivo glucocorticoid excretion. Unilateral adrenalectomy resolved both mineralocorticoid and glucocorticoid excess. Postoperative evidence of adrenal insufficiency was found in 13 (29%) of 45 consecutively tested patients. CONCLUSION. Our data indicate that glucocorticoid cosecretion is frequently found in primary aldosteronism and contributes to associated metabolic risk. Mineralocorticoid receptor antagonist therapy alone may not be sufficient to counteract adverse metabolic risk in medically treated patients with primary aldosteronism
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