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1.
Studies have found that a large number of inflammatory cells, P-selectin, and mature dendritic cells (DCs) are expressed in the damaged and shoulder parts of atherosclerotic plaque, which demonstrates that P-selectin and mature DCs participate in the immune inflammatory response leading to the development of atherosclerosis. However, it is unclear how the above factors interact in this setting. In this study, we investigated the role of P-selectin and its receptor, P-selectin glycoprotein ligand (PSGL)-1 in atherosclerosis, with the finding that DC surface marker expression was consistently high in the P-selectin group while consistently low in the PGSL-1 + DCs group, with CD40 and CD86 expressed by 3.84% and 2.05% for the latter. The highest expression of CD80, CD83, and MHC II was discovered in the DC group, at 7.49%, 3.68%, and 8.98%, respectively. Results of this study are similar to those obtained previously by Ye et al. (2017), which showed larger atherosclerotic lesions in mice that received exogenous DCs, compared with those treated with PBS. In this study, the greatest level of atherosclerosis, fibrosis, and lipid deposition was also seen in mice that received exogenous DCs.  相似文献   

2.
Investigation on possible induction of adaptive response (AR) by high-liner energy transfer (LET) particle radiation for protection against low-LET photon radiation-induced detrimental effects has not yet been performed in utero. This study verified if an AR could be induced by high-LET particle radiation from accelerated heavy ions against low-LET X-ray radiation-induced detrimental effects on fetal mice. Total body irradiation of pregnant C57BL/6J mice were performed by delivering a priming dose ranging from 10 mGy to 320 mGy of particle radiation on gestation day 11 followed one day later by a challenge dose at 3500 mGy from X-ray radiation. The monoenergetic beams of carbon, silicon and iron with the LET values of about 15, 55, and 200 KeV/μm, respectively, were examined. Significant suppression by the priming radiation of the detrimental effects (fetal death, malformation, or low body weight) was used as the endpoints for judgment of a successful AR induction on gestation day 18. Existence of AR was not observed. On the other hand, the priming dose of high-LET particle radiation, in some cases, even increased the detrimental effects induced by the challenge dose from low-LET X-ray radiation. Although existence of AR induced by high-LET radiation in cultured mammalian cells in vitro and in certain tissues of laboratory mice in vivo was demonstrated, the present study did not suggest that low dose of high-LET particle radiation could induce an AR in fetal mice in utero under the setup of our experimental system.  相似文献   

3.
This study aimed to determine whether the application of extra hydrophobic resin (EHR) or double layer (DL) improves microtensile bond strength (μTBS) of two universal adhesives to composite resin. Composite blocks were fabricated and exposed to thermal cycles. The specimens were horizontally sectioned into two halves. Scotch Bond Universal (SBU) and Clearfil S3 Bond Universal (CSBU) were applied to the ground composite surface according to the manufacturers' instructions, or with DL application or EHR application. The repair composite was incrementally placed to bonded planes. Composite sticks were achieved and tensed with a universal testing machine, followed by examining the fracture surfaces by a scanning electron microscope. Data were evaluated by Weibull analysis (shape and scale [σθ and σ0.10] parameters) using the maximum likelihood method. The σθ and σ0.10, respectively, estimate strength at 63.2 and 10% probability of failure. Shape parameter values showed significant differences among treatments. DL application of CSBU did not affect μTBS values at σθ of failure but caused to decrease μTBS values at σ0.10 of failure. DL application of SBU reduced μTBS values at σθ of failure. DL or EHR coating did not improve μTBS of SBU. EHR application increased μTBS of CSBU, whereas DL application did not benefit.  相似文献   

4.
Fractal analysis is a reliable method for describing, summarizing object complexity and heterogeneity and has been widely used in biology and medicine to deal with scale, size and shape management problems. The aim of present survey was to use fractal analysis as a complexity measure to characterize mast cells (MCs) degranulation in a rainbow trout ex vivo model (isolated organ bath). Compound 48/80, a condensation product of N‐methyl‐p‐methoxyphenethylamine with formaldehyde, was adopted as MCs degranulation agent in trout intestinal strips. Fractal dimension (D), as a measure of complexity, ‘roughness’ and lacunarity (λ), as a measure of rotational and translational invariance, heterogeneity, in other words, of the texture, were compared in MCs images taken from intestinal strips before and after compound 48/80 addition to evaluate if and how they were affected by degranulation. Such measures were also adopted to evaluate their discrimination efficacy between compound 48/80 degranulated group and not degranulated group and the results were compared with previously reported data obtained with conventional texture analysis (image histogram, run‐length matrix, co‐occurrence matrix, autoregressive model, wavelet transform) on the same experimental material. Outlines, skeletons and original greyscale images were fractal analysed to evaluate possible significant differences in the measures values according to the analysed feature. In particular, and considering outline and skeleton as analysed features, fractal dimensions from compound 48/80 treated intestinal strips were significantly higher than the corresponding untreated ones (paired t and Wilcoxon test, p < 0.05), whereas corresponding lacunarity values were significantly lower (paired Wilcoxon test, p < 0.05) but only for outline as analysed feature. Outlines roughness increase is consistent with an increased granular mediators interface, favourable for their biological action; while lacunarity (image heterogeneity) reduction is consistent with the biological informative content decrease, due to granule content depletion. In spite of the significant differences in fractal dimension and lacunarity values registered according to the analysed feature (greyscale obtained values were, on average, lower than those obtained from outlines and skeletons; General Linear Model, p < 0.01), the discrimination power between not degranulated and degranulated MCs was, on average, the same and fully comparable with previously performed texture analysis on the same experimental material (outline and skeleton misclassification error, 20% [two false negative cases]; greyscale misclassification error, 30% [two false negative cases and one false positive case]). Fractal analysis proved to be a reliable and objective method for the characterization of MCs degranulation.  相似文献   

5.
Solid-state thermoelectric generators (TEGs) based on the Seebeck effect to convert temperature gradients, ΔT [K], into electrical energy are being used in an increased number of stand-alone microsystems applications. These generators are composed by at least one pair of p- and n-type thermoelectric elements with high figures-of-merit, ZT, to perform such a conversion. The exact behavior knowledge of generators is mandatory in order to decide the most suitable for the target application. The focus of this paper is to present a methodology to characterize thermoelectric generators, by measuring their behavior for different types of loads. The measurements were done with the help of commercial thermoelectric generators (thermoelectric modules TEC1-12707) and a measurement setup composed by a controlled hot-plate, a controlled cooling fan (above an heat dissipator), a set of two thermistors for measuring the temperature, a personal computer with the data acquisition board model NI USB-6009 and the LabView software from National Instruments for acquiring the measures and for controlling both the hot-plate and the cooling fan. The thermoelectric modules TEC1-12707 was selected due to its compact size (e.g., 40 mm × 40 mm) and because it can withstand temperatures up to 450 K without degrading the quality of measurements. A SPICE model for thermoelectric modules TEC1-12707 was also obtained: an open-circuit voltage of Vopen = 53.17 × ΔT [mV] and an internal resistance of R0 = 3.88 Ω with a tolerance of ΔRint = 0.13 Ω such that Rint = R0 ± ΔRint = 3.88 ± 0.13 Ω. The measurements done under the maximum output power delivery condition (for the maximum temperature gradient of ΔT = 51 °C) resulted in the maximum output power of Pout = 500 mW, as well as in the output current and voltage of Iout = 357 mA and Vout = 1.40 V, respectively. The load resistance of 3.92 Ω (Vout/Iout) is also in accordance with the measurements because it is located in the range [μσ, μ + σ] Ω, where μ = R0 = 3.88 Ω and σ = ΔRint = 0.13 Ω. An Agilent multimeter model 34410A with 6½ digits was used for measuring the voltages at the TEG’s output and the respective currents.  相似文献   

6.
The objective of this study was to evaluate and correlate light transmittance (T), initial degree of conversion (IDC), and degree of conversion after 24 hr (DC24) for 22 composite resins (CR) for enamel and dentin use. The transmittance (n = 10) was measured with a spectrometer at a wavelength of 468.14 nm. The degree of conversion (DC; n = 5) was measured with Fourier Transform Near‐Infrared Spectroscopy before polymerization, immediately after photoactivation, and 24 hr after photoactivation. Both sets of values are provided as percentages. ANOVA and Games‐Howell (α = 5%) tests showed that Filtek Supreme Ultra gave the highest T values of all enamel CRs, while Esthet‐X HD presented the lowest. Meanwhile, Venus diamond gave the highest values of all dentin CRs, while Esthet‐X HD gave the lowest. For IDC and DC24, ANOVA showed differences between individual CRs and the two CR types (p < .0001). Despite the limitations of this study, it can be concluded that there was no correlation between T and either IDC or DC24 (p > .05); however, IDC and DC24 were strongly correlated (p < .05) by Pearson's correlation. That being said, as a higher DC reflects better mechanical properties, certain conclusions can be drawn about overall performance. The best IDC values were observed for the Opallis enamel resin and the Opallis and Premise dentin resins. Meanwhile, the best DC24 values were observed for the Opallis, Charisma, and Premise enamel resins and the Opallis and Premise dentin resins. Degree of conversion and light transmittance showed differences between composite resin types (enamel and dentin) and brands. It is important to know at the moment of composite choice taking into account mechanical and optical properties.  相似文献   

7.
Mines, quarries, and construction sites face blasting environmental problems due to high level of ground vibrations. This phenomena can cause injury to both human and damage to structures in the blasting environment. To estimate ground vibration, several empirical predictors have been established by various researchers, while these predictors are not commonly enforceable beyond the particular conditions. However, ground vibration prediction is a complicated issue in consequence of the fact that a large number of influential factors are involved. In this study, a support vector machine (SVM) was applied and developed to predict ground vibration in blasting operations of Bakhtiari Dam, Iran. To achieve this aim, 80 blasting works were investigated and results of peak particle velocity (PPV) as a vibration index, distance from the blast-face and maximum charge per delay were measured and monitored to utilize in the modeling. To demonstrate applicability of the SVM model for prediction of PPV, several empirical equations were also employed and the relevant site constants were proposed. In the analyses procedure of this study, 60 datasets were used for model development and remaining 20 datasets were applied to check the performance capacity of the developed model. After comparing the results obtained from SVM and empirical equations, it was found that the SVM method provides higher performance capacity in predicting PPV compared to empirical equations.  相似文献   

8.
Venturi cavitation erosion tests were performed and correlated with bubble collapse pulse height spectra measured by a microtransducer. The effects of the throat velocity and the cavitation number σ (referred to the downstream pressure and throat velocity) on the erosion rate (MDPR) were studied. The velocity damage exponent was 4.11 for 0.62 ? σ ? 0.80, while the MDPR is almost independent of velocity for σ = 0.85. The MDPR decreases with increased σ for 0.62 ? σ ? 0.85. The data were reduced to “acoustic power” (from pulse height spectra) and “erosion power” (the ultimate resilience multiplied by the MDPR). A near-linear relationship was found between these. Their reciprocal ratio ηcav ≈ 7 × 10?11. For σ = 0.62, the data deviated from the others, possibly because of the work hardening of the eroded surface.  相似文献   

9.
Fluorescence in situ hybridization on human metaphase chromosomes is detected by near-field scanning optical microscopy. This combination of cytochemical and scanning probe techniques enables the localization and identification of several fluorescently labelled genomic DNA fragments on a single chromosome with an unprecedented resolution. Three nucleic acid probes are used: pUC1. 77. p1–79 and the plasmid probe α-spectrin. The hybridization signals are very well resolved in the near-field fluorescence images, while the exact location of the probes can be correlated accurately with the chromosome topography as afforded by the shear force image.  相似文献   

10.
Fluorescence in situ hybridization coupled with far‐field fluorescence microscopy is a commonly used technique to visualize chromosomal aberrations in diseased cells. To obtain the best possible results, chromatin integrity must be preserved to ensure optimal hybridization of fluorescence in situ hybridization probes. However, biological samples are known to degrade and storage conditions can be critical. This study concentrates its investigation on chromatin stability as a function of time following fluorescence in situ hybridization type denaturing protocols. This issue is extremely important because chromatin integrity affects the fluorescence response of the chromosome. To investigate this, metaphase chromosome spreads of human lymphocytes were stored at both ?20 and ?80 °C, and were then imaged using scanning near‐field optical microscopy over a nine month period. Using the scanning near‐field optical microscope's topography mode, chromosome morphology was analysed before and after the application of fluorescence in situ hybridization type protocols, and then as a function of storage time. The findings revealed that human chromosome samples can be stored at ?20 °C for short periods of time (~ several weeks), but storage over 3 months compromises chromatin stability. Topography measurements clearly show the collapse of the stored chromatin, with variations as large as 60 nm across a chromosome. However, storage at ?80 °C considerably preserved the integrity with variations in topography significantly reduced. We report studies of the fluorescent response of stored chromosomes using scanning near‐field optical microscopy and their importance for gaining further understanding of chromosomal aberrations.  相似文献   

11.
We describe a spectrometer-dosimeter for simultaneous and independent measurements of the spectral and dose characteristics of α-, β-, and γ-radiations. The particle-identification method used in the spectrometers-dosimeters is based on simultaneous measurement of the particle energyE and its specific loss ΔE with semiconductor detectors. The dependences ΔE(E), preliminarily computed for each sort of particles, are stored in programmable read-only memories. Comparison of the expected and measured values of ΔE for the measured energyE completely defines the type of a particle. The method makes possible the determination of the spectral and dose characteristics of different types of radiation, as well as the radionuclide type and its concentration in the analyzed substance. It is shown that instruments based on this principle provide environmental radiation monitoring, including monitoring of radon, thoron, and their products.  相似文献   

12.
The purpose of this study was to examine the effect of different cleaning methods and resin cements on the shear bond strength (SBS) of contaminated zirconia. A total of 92 disc-shaped zirconia specimens were contaminated with different procedures. Then, the specimens were grouped according to cleaning methods and resin cements: no cleaning + Variolink Esthetic DC (CNV), no cleaning + Panavia V5 (CNP), sandblasted + Variolink Esthetic DC (SBV), sandblasted + Panavia V5 (SBP), Ivoclean + Variolink Esthetic DC (ICV), Ivoclean + Panavia V5 (ICP), Katana Cleaner + Variolink Esthetic DC (KCV), and Katana Cleaner + Panavia V5 (KCP). Following an aging protocol in a 37°C for 1 week, SBS analysis was performed with a universal test machine. For the surface topography and elemental analysis, scanning electron microscopy and energy-dispersive X-ray spectroscopy (EDS) were used. Significance was evaluated as p < .05 and p < .01. The highest SBS results were found in the SBP group, showing a statistically significant difference from all other groups (p < .05). For the same cleaning method, Panavia V5 showed statistically significantly higher SBS values than Variolink Esthetic DC (p < .01), except the CNP–CNV (p = .880) and KCP–KCV (p = .082) groups. The most detected surface elements by EDS were Zr, O, C, and N, respectively. The contaminated zirconia surfaces must be cleaned for successful adhesion. The use of phosphate-containing adhesives in combination with sandblasting will increase the adhesion strength, and universal cleaning agents can be a good alternative to sandblasting.  相似文献   

13.
We have studied the development of a new procedure based on atomic force microscopy (AFM) for the analysis of metaphase chromosome. The aim of this study was to obtain detailed information about the specific locations of genes on the metaphase chromosome. In this research, we performed the manipulation of the metaphase chromosome by using novel AFM probes to obtain chromosome fragments of a smaller size than the ones obtained using the conventional methods, such as glass microneedles. We could pick up the fragment of the metaphase chromosome dissected by the knife-edged probe by using our tweezers-type probe.  相似文献   

14.
We propose an algorithmic technique for accelerating maximum likelihood (ML) algorithm for image reconstruction in fluorescence microscopy. This is made possible by integrating Biggs–Andrews (BA) method with ML approach. The results on widefield, confocal, and super‐resolution 4Pi microscopy reveal substantial improvement in the speed of 3D image reconstruction (the number of iterations has reduced by approximately one‐half). Moreover, the quality of reconstruction obtained using accelerated ML closely resembles with nonaccelerated ML method. The proposed technique is a step closer to realize real‐time reconstruction in 3D fluorescence microscopy. Microsc. Res. Tech. 78:331–335, 2015. © 2015 Wiley Periodicals, Inc.  相似文献   

15.
An atomic force microscope (AFM) was combined with a conventional optical microscope. The optical microscope proved to be very convenient for locating objects of interest. In addition, the high-resolution AFM image can be compared directly with the traditional optical image. The instrument was used to study chromosome structures. High-resolution chromosome images revealed details of the 30-nm chromatide structure, confirming earlier electron microscopic observations. Chromosomes treated with trypsin revealed a banding pattern in height which is very similar to the optical image observed after staining with Giemsa. Furthermore, it is shown that the AFM can be used to locate DNA probes on in situ hybridized chromosomes. Images of the synaptonemal complex isolated from rat spermatocytes revealed details that improve the understanding of the three-dimensional structure of this protein.  相似文献   

16.
The paper describes a method for estimating reliability of acoustic emission (AE) tests of large-scale metallic structures with due account of physical and mechanical features of cracking and resulting radiation. Amplitude spectra (A-curves) of acoustic emission pulses obtained in tests of cracking samples are given. Such spectra are used in assessing the reliability of tests of large-scale objects. The reliability of acoustic emission tests of pipelines has been analyzed.  相似文献   

17.
Parthenogenetic embryos are an ethically acceptable alternative for the derivation of human embryonic stem cells. In this work, we propose a new strategy to produce bovine parthenogenetic embryos inhibiting the emission of the first polar body during in vitro maturation, and allowing the extrusion of the second polar body during oocyte activation. Cytochalasin B, an inhibitor of actin microfilaments, was employed during in vitro maturation to inhibit first polar body emission or during parthenogenetic activation to block second polar body emission. Only one polar body was inhibited in each strategy in order to keep the diploid chromosome set. In experiment 1, the effect of cytochalasin B on in vitro maturation of bovine oocytes was evaluated. Most oocytes (77%) were arrested at a meiotic stage characterized by the presence of a large internal metaphase plate and absence of polar body. In experiment 2, development of embryos exposed to cytochalasin B during in vitro maturation (CytoB-IVM) or during activation (CytoB-ACT) was compared. Developmental rates did not differ between diploidization strategies, even when three agents were employed to induce activation. Both groups, CytoB-IVM and CytoB-ACT, tended to maintain diploidy. CytoB-IVM parthenogenesis could help to obtain embryos with a higher degree of homology to the oocyte donor.  相似文献   

18.
An instrument for measuring the intensity and dose of cancerigenic radiation from the Sun and artificial sources has been developed. A 4H-SiC Schottky barrier photodetector is used as the sensor. The sensitivity spectrum of the photoelectric transducer lies in the region 240–300 nm and has a maximum at 260 nm. The quantum efficiency is ≈0.3 electrons/photon (at λ = 254 nm), and its temperature coefficient at T = 250–310 K is < 0.1%/°C. The dimensions of the device are 3 × 6 × 11 cm.  相似文献   

19.
The objective of this study was to examine the effects of extrinsic or intrinsic acids on nanofilled and bulk fill resin materials in vitro. A total of 90 disks were prepared using dental restorative material (Filtek Z350XT, GrandioSO, Filtek Bulk Fill, X‐tra fil). Thirty disks of each material were sub‐divided into three groups (n = 10) that were immersed for 7 days in deionized water (DW), 5% citric acid (CA—pH 2.1), or 0.1% hydrochloric acid (HCl—pH = 1.2). Surface hardness and roughness (stylus profilometer by Ra parameter) analysis were performed before and after immersion. Morphological changes were evaluated by scanning electron microscopy. The data were analyzed by two‐way ANOVA and Tukey's test (α = 0.05). All tested materials did not show significant differences in the effects of the DW, CA, or HCl solutions on surface roughness (p = .368). Likewise, the hardness loss was not affected by the solutions tested (p = .646), but there was a difference in the resin type (p = .002). Filtek Bulk Fill resin hardness was less affected, while Filtek Z350XT and GrandioSO presented the most hardness loss after 7 days of solution immersion. In terms of this experimental study, the results demonstrate the effectiveness of the mechanical properties (roughness and hardness surface) of nanofilled and bulk fill resin materials to resist erosion from extrinsic and intrinsic acids, therefore being potential candidates for dental applications.  相似文献   

20.
The tritium content of nervous tissue sections is calculated from grain-density of autoradiographs without loss in anatomical information. The calculation is not based on determination of (expected) grain numbers but on photometric measurements (SKphot), interpreted as the result of the function of exposure time (T) and incorporated activity (β): SKphot = f (T, β). As experimental radiation standards homologous material (optic nerve preparations) with different activities determined by liquid scintillation counting has been used. Exposure times between 12 h and 28 weeks for these preparations with known radioactivities yielded a set of curves (nomogram) relating photometric values to exposure times. At any given exposure time the knowledge of photometric readings and related radioactivities within that set of curves enabled the development of a function covering all photometer readings within the range of the nomogram. Thus, any photometric reading could be correlated to the corresponding radioactivity. Such a function has been applied for the transformation of photometric values obtained from particular brain-section areas exposed for 16 weeks. Since the results are given in Bq, they may be related and, if necessary, corrected to results obtained by other tritium detection methods. Terminology used in the text: experimental radiation source = experimental standards prepared from optic nerve sections; standard radiation source = polymer reference source.  相似文献   

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