Dense microwave dielectric ceramics of Ce
2
Zr
1
−
x
(Al
1/2
Ta
1/2
)
x
3
(MoO
4
)
9
(CZMAT) (
x
= 0.02–0.10) were prepared by the conventional solid-state route. The effects of (Al
1/2
Ta
1/2
)
4+
...on their microstructures, sintering behaviors, and microwave dielectric properties were systematically investigated. On the basis of the X-ray diffraction (XRD) results, all the samples were matched well with Pr
2
Zr
3
(MoO
4
)
9
structures, which belonged to the space group
R
3
¯
c
. The lattice parameters were obtained using the Rietveld refinement method. The correlations between the chemical bond parameters and microwave dielectric properties were calculated and analyzed by using the Phillips—Van Vechten—Levine (P—V—L) theory. Excellent dielectric properties of Ce
2
Zr
0.94
(Al
1/2
Ta
1/2
)
0.06
3
(MoO
4
)
9
with a relative permittivity (
ε
r
) of 10.46, quality factor (
Q
×
f
) of 83,796 GHz, and temperature coefficient of resonant frequency (
τ
f
) of −11.50 ppm/°C were achieved at 850 °C.
•Embedded piezoelectric ultrasonic transducers were developed.•Corrosion of reinforcement concrete was monitored based on the ultrasonic method.•Three corrosion periods can be obtained based on the ...acoustic parameters.
The corrosion behavior of steel in concrete is an engineering issue that needs to be monitored to ensure structural safety. Novel cement/polymer-based piezoelectric composites were used to fabricate embedded ultrasonic transducers. This study investigated the corrosion development of reinforcement bar in concrete by employing ultrasonic transmission technique. The transmitted ultrasonic wave and acoustic parameters were extracted to reveal the corrosion process of steel. Results show that ultrasonic time- and frequency-domain spectra have weak amplitude attenuation when the corrosion rate of steel is less than 1%. Corrosion then weakens further when the corrosion rate is higher than 5%. A similar variation is observed on the frequency-domain spectrum. Variations in the corrosion rates of steel bars in concrete can be categorized into three periods based on the acoustic parameters, namely, the initial corrosion period when the corrosion rate is less than 1%, rapid corrosion period at a corrosion rate of 1%–6%, and corrosion development period when the corrosion rate is higher than 6%.
As the most commonly occurring cancer in women worldwide, breast cancer poses a formidable public health challenge on a global scale. Breast cancer consists of a group of biologically and molecularly ...heterogeneous diseases originated from the breast. While the risk factors associated with this cancer varies with respect to other cancers, genetic predisposition, most notably mutations in BRCA1 or BRCA2 gene, is an important causative factor for this malignancy. Breast cancers can begin in different areas of the breast, such as the ducts, the lobules, or the tissue in between. Within the large group of diverse breast carcinomas, there are various denoted types of breast cancer based on their invasiveness relative to the primary tumor sites. It is important to distinguish between the various subtypes because they have different prognoses and treatment implications. As there are remarkable parallels between normal development and breast cancer progression at the molecular level, it has been postulated that breast cancer may be derived from mammary cancer stem cells. Normal breast development and mammary stem cells are regulated by several signaling pathways, such as estrogen receptors (ERs), HER2, and Wnt/β-catenin signaling pathways, which control stem cell proliferation, cell death, cell differentiation, and cell motility. Furthermore, emerging evidence indicates that epigenetic regulations and noncoding RNAs may play important roles in breast cancer development and may contribute to the heterogeneity and metastatic aspects of breast cancer, especially for triple-negative breast cancer. This review provides a comprehensive survey of the molecular, cellular and genetic aspects of breast cancer.
•Novel embedded piezoelectric sensor for SHM of concrete structure was developed.•Influence of temperature on EMI method were studied at different frequency ranges.•The electromechanical impedance ...responds differently to load from orthotropic direction.
A kind of embedded impedance-based piezoelectric sensor was fabricated by using mixture of cement powder and epoxy resin as packaging layer. Effects of temperature and load on impedance and conductance spectra of the sensor were investigated. The results show that the baseline of conductance spectra shifts with increasing temperature, and the resonance peaks in the conductance spectra show obvious temperature dependence. The impedance spectra of the embedded sensor under external load from different direction was discussed. The results indicate that the sensor is sensitive to the initial load when the external load is parallel to the thickness direction of the sensor. When the load is along the planar direction of the sensor, the impedance spectra of the sensor show good correlation with the load variation. The root mean square deviation (RMSD) index was also employed here to intuitively indicate the impedance variation of the embedded PZT sensor under temperature and load.
Abstract
The BL Lacertae OJ 287 is a supermassive black hole binary system with complex physics of its irregular flares. During 2016 October–2017 April, a surprising outburst in the X-ray, UV, and ...optical bands was detected, while no variability was seen in the
γ
-ray light curve. During the outburst, the X-ray light curves were dominated by the soft X-rays, whose peak in luminosity was ∼10
46
erg s
−1
—more than 10 times higher than the mean level before the outburst—and a “softer-when-brighter” phenomenon was exhibited. These above phenomena have been reported by some previous works. The hardness ratio showed negligible evolution with flare time and soft X-ray luminosity. Critically, the luminosity of the soft X-rays decayed following a power law of
t
−5/3
, which occurs in most tidal disruption events (TDEs), and a similar trend can be seen in the UV and optical bands during the soft X-ray declining period. Helium and oxygen narrow emission lines are strengthened prominently in the optical spectra of postoutburst epochs, that could be attributed to the surrounding gas caused by TDE. We discuss three possible origins of the event, including the jet’s precession, the aftereffects of the black hole–disk impaction, and the TDE. Our results show that the TDE is the more likely scenario to explain the outburst.
Utilization of granite scraps and minor clay tailings to prepare closed-pore foam ceramic was investigated using SiC as foaming agent. The foam ceramic presented promising results with a bulk density ...of 237.4kg/m3, compressive strength of 0.85MPa, flexural strength of 0.42MPa, porosity of 83.31%, water absorption of 2.21% and thermal conductivity of 0.051W/(mk), which had good potential application in the field of building insulation.
This work is concerned with investigating the effect of substrate hydrophobicity and zeta potential on the dynamics and kinetics of the initial stages of bacterial adhesion. For this purpose, ...bacterial pathogens Staphylococcus aureus and Escherichia coli O157:H7 were inoculated on the substrates coated with thin thiol layers (i.e., 1-octanethiol, 1-decanethiol, 1-octadecanethiol, 16-mercaptohexadecanoic acid, and 2-aminoethanethiol hydrochloride) with varying hydrophobicity and surface potential. The time-resolved adhesion data revealed a transformation from an exponential dependence to a square root dependence on time upon changing the substrate from hydrophobic or hydrophilic with a negative zeta potential value to hydrophilic with a negative zeta potential for both pathogens. The dewetting of extracellular polymeric substances (EPS) produced by E. coli O157:H7 was more noticeable on hydrophobic substrates, compared to that of S. aureus, which is attributed to the more amphiphilic nature of staphylococcal EPS. The interplay between the timescale of EPS dewetting and the inverse of the adhesion rate constant modulated the distribution of E. coli O157:H7 within microcolonies and the resultant microcolonial morphology on hydrophobic substrates. Observed trends in the formation of bacterial monolayers rather than multilayers and microcolonies rather than isolated and evenly spaced bacterial cells could be explained by a colloidal model considering van der Waals and electrostatic double-layer interactions only after introducing the contribution of elastic energy due to adhesion-induced deformations at intercellular and substrate-cell interfaces. The gained knowledge is significant in the context of identifying surfaces with greater risk of bacterial contamination and guiding the development of novel surfaces and coatings with superior bacterial antifouling characteristics.
•Preparation and application two SiO2@TiO2 core-shell composites with different deposited densities.•Excellent rhodamine B-removal efficiency before and after curing and accelerated weathering ...processes.•Pozzolanic reaction of samples and calcium hydroxide and changed morphologies.•Changing the structure of the C-S-H.•Promoting the transformation of C3S.
For surface functionalization of cement-based materials with photocatalytic properties, weak adhesion between photocatalysis and matrix worsens these properties and results in poor weathering resistance in outdoor environments. To overcome these problems, in this study, two SiO2/TiO2 composites, with different deposited densities of TiO2 nanoparticles on a SiO2 sphere, were prepared and used for surface coating of cement-based materials. The two composites show different efficiencies. The photocatalytic results show that the coated cement pastes exhibited excellent rhodamine B-removal efficiency before and after curing and accelerated weathering processes, indicating that SiO2 in the system hasacrucialeffect as a ‘glue’ preventing the release of TiO2. The bonding mechanism was revealed by the reaction of the samples and main components and hydration products (such as CH, C-S-H and C3S).
Abstract ASASSN-14ko was identified as an abnormal periodic nuclear transient with a potential decreasing period. Its outbursts in the optical and UV bands have displayed a consistent and smooth ...“fast rise and slow decay” pattern since its discovery, which has recently experienced an unexpected alteration in the last two epochs, as revealed by our proposed high-cadence Swift observations. The new light curve profiles show a bump during the rising stages and a rebrightening during the declining stages, making them much broader and symmetrical than the previous ones. In the last two epochs, there is no significant difference in the X-ray spectral slope compared to the previous one, and its overall luminosity is lower than those of the previous epochs. The energy released in the early bump and rebrightening phases (∼10 50 erg) could be due to collision of the stripped stream from partial tidal disruption events with an expanded accretion disk. We also discussed other potential explanations, such as disk instability and star–disk collisions. Further high-cadence multiwavelength observations of subsequent cycles are encouraged to comprehend the unique periodic source with its new intriguing features.
Hepatitis C virus (HCV) has been reported to regulate cellular microRNAs (miRNAs). The HCV core protein is considered to be a potential oncoprotein in HCV-related hepatocellular carcinoma (HCV-HCC), ...but HCV core-regulated miRNAs are largely unknown. Our preliminary experiments revealed significant down-regulation of microRNA-152 (miR-152) by HCV core protein in HepG2 cells. Through target gene prediction softwares, Wnt1 was predicted to be a potential target of miR-152. The present study was initiated to investigate whether miR-152 is aberrantly regulated by the HCV core protein, and involved in the regulation of the aberrant proliferation of HCV-HCC cells.
MiR-152 levels were examined by stem-loop real-time RT-PCR (SLqRT-PCR). Cell proliferation was analyzed by MTT and colony formation assay. Cell cycle analysis was performed by flow cytometry. Luciferase reporter assay was conducted to confirm miRNA-target association. Wnt1 expression was determined by real-time qPCR and Western blotting.
HCV core protein significantly suppressed miR-152 expression, and led to significant Wnt1 up-regulation with a concomitant aberrantly promoted proliferation. Moreover, we validated that miR-152 inhibition promoted, while miR-152 mimics inhibited cell proliferation. Using, qRT-PCR and western blot, Wnt1 was demonstrated to be regulated by miR-152. Luciferase activity assay showed that while miR-152 mimics significantly reduced the luciferase activity by 83.76% (P<0.0001), miR-152 inhibitor showed no effect on luciferase reporter. Most notably, salvage expression of miR-152 after Ad-HCV core infection for 24 h almost totally reversed the proliferation-promoting effect of the HCV core protein, and meanwhile, reduced the expression of both Wnt1 mRNA and protein to basal levels.
These findings provide important evidence that the reduced miR-152 expression by HCV core protein can indirectly lose an inhibitory effect on Wnt1, which might, at least partially lead to cell proliferation of liver cancer cells. MiR-152 may have a therapeutic potential to suppress liver cancer proliferation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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