This study aimed to evaluate the effect of n‐propyl gallate as pre‐treatment for resin‐dentin bond strength. The dentin pre‐treatments evaluated included propyl gallate of concentrations 0.1% (w/v), ...1.0% (w/v), and 10.0% (w/v), as well as glutaraldehyde 5.0% (v/v), and distilled water as a control treatment. Dentin specimens were prepared for Fourier Transformed Infrared Spectroscopy (FT‐IR) (n = 3/pre‐treatment). Pre‐treatments were actively applied to dentin blocks before performing the adhesive procedure to composite resin. Microtensile bond strength to dentin (μTBS) (n = 8/pre‐treatment) was determined after 24 h and 6 months of storage. Data were submitted to a two‐way ANOVA, followed by Tukey's post hoc test. As for FT‐IR, propyl gallate 1%‐treated specimens presented higher water, carbonate, collagen, and amide absorbance rates compared to other tested groups, while specimens pre‐treated with glutaraldehyde and distilled water presented similar absorbance curves. Regarding μTBS, all concentrations of propyl gallate resulted in statistically significant higher bond strength values than distilled water at 24 h. After 6 months of storage, propyl gallate 0.1% was the only group that maintained μTBS over time. Propyl gallate 0.1% might be a suitable dentinal pre‐treatment due to being able to present chemical bonds with demineralized dentin and providing resin‐dentin bond stability after 6 months of storage.
To evaluate the association between Ethanol Wet Bonding (EWB) and collagen cross-linking agents (CLA) on the mechanical properties of collagen and on the physical chemical proprieties of an ...etch-and-rise adhesive to dentin. Demineralized dentin bars (n = 10) were immersed, for 1 min or 1 h, according to the respective groups: distilled water control (WC); absolute ethanol (EA); absolute ethanol with the incorporation of proanthocyanidins 6,5% (PAC + AE); absolute ethanol with the incorporation of 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide 0.3 M (EDC + EA); absolute ethanol with the incorporation of 5% glutaraldehyde (GA + AE). All as solutions used as dentin primer per 1-min of application, for 3-point bending test was performed to evaluate the modulus of elasticity (ME) and mass change (MC) of collagen treated with the respective solutions, at different times of application (1min and 1h). The in situ degree conversion DC (n = 3), microtensile bond strength testing μTBS (n = 6) and micropermeability MI (n = 3) of the teeth restored with the respective treatments were analyzed. After 1 min and 1 h of application, it was observed that WC group showed the lowest ME (p < 0,05). The groups EDC + AE, GA + AE and AE presented a better ME with 1 h of application (p < 0,05), since the PAC + AE and WC were statistically similar. Treatments did not influence DC and μTBS (p > 0,05). In the micropermeability the WA showed the worst results. The association of EWB technique and CLA improved the mechanical properties of the collagen, but it showed no influence in the adhesive procedure.
By using products of the cloud model, National Centers for Environmental Prediction (NCEP) Final Operational Global Analysis (FNL) reanalysis data, and Doppler weather radar data, the mesoscale ...characteristics, microphysical structure, and mechanism of two hail cloud systems which occurred successively within 24 h in southeastern Yunnan have been analyzed. The results show that under the influence of two southwest jets in front of the south branch trough (SBT) and the periphery of the western Pacific subtropical high (WPSH), the northeast-southwest banded echoes affect the southeastern Yunnan of China twice. Meanwhile, the local mesoscale radial wind convergence and uneven wind speed lead to the intense development of convective echoes and the occurrence of hail. The simulated convective cloud bands are similar to the observation. The high-level mesoscale convergence line leads to the development of convective cloud bands. The low-level wind direction or wind speed convergence and the high-level wind speed divergence form a deep tilted updraft, with the maximum velocity of 15 m·s−1 at the −40~−10 °C layer, resulting in the intense development of local convective clouds. The hail embryos form through the conversion or collision growth of cloud water and snowflakes and have little to do with rain and ice crystals. Abundant cloud water, especially the accumulation region of high supercooled water (cloud water) near the 0 °C layer, is the key to the formation of hail embryos, in which qc is up to 1.92 g·kg−1 at the −4~−2 °C layer. The hail embryos mainly grow by collision-coalescence (collision-freezing) with cloud water (supercooled cloud drops) and snow crystal riming.
In this paper, a compact antenna with three operational bands, including a (notched) ultra-wideband (UWB), and its array for multiple-in multiple-out (MIMO) applications are reported. The antenna is ...composed of a folded patch with a shoring wall fed by a folded planar monopole with a 3-D U-slot cut. The operation of the antenna relies on the monopole-fed patch mode at low frequencies and reflector-backed monopole radiation in the middle- and high-frequency bands, which is able to cover almost all the wireless service bands in the sub-6 GHz regime, including a continuous UWB with a ratio bandwidth of 4:1. A narrow stopband can be placed within the UWB by integrating a symmetric pair of 3-D meandered slots on the folded monopole feed. A prototype of the antenna was fabricated, which has a form factor of <inline-formula> <tex-math notation="LaTeX">0.16\lambda _{L} \times 0.13\lambda _{L} \times 0.09\lambda _{L} </tex-math></inline-formula>, where <inline-formula> <tex-math notation="LaTeX">\lambda _{L} </tex-math></inline-formula> is the wavelength at the lowest operating frequency, and experimentally achieves three <inline-formula> <tex-math notation="LaTeX">S_{11} < -10 </tex-math></inline-formula> dB bands of 0.72-2.96, 3.25-3.59, and 5.06-6.21 GHz, with a stopband at around 1.5 GHz. It has a unidirectional radiation pattern with a wide beamwidth and a realized gain of more than 4 dBi in the majority of the operational bands. Moreover, a <inline-formula> <tex-math notation="LaTeX">2 \times 1 </tex-math></inline-formula> MIMO array of the proposed antennas is further investigated for offering both spatial and pattern diversities. The fabricated array prototype accomplishes a weak mutual coupling below −23 dB and a small envelope correlation coefficient lower than 0.001 in the targeted bands. The demonstrated antenna and its MIMO array will be highly useful for multiservice software-defined radio devices and various other wireless communication systems for numerous applications.
In this paper, a 24.25–30 GHz fully integrated radio frequency (RF) up‐down converter with harmonic distortions rejection for 5G millimeter wave radio channel emulator applications is proposed and ...implemented in a 0.1‐μm GaAs pseudomorphic high‐electron‐mobility transistor technology. The RF up‐down converter integrates a frequency doubling amplifier chain local oscillator, a harmonic suppression mixer, and three frequency selective filters for unwanted harmonics suppression. To prevent the unwanted harmonics from leaking into the RF band, a higher sideband and high‐intermediate frequency mixer core with harmonic suppression filters is proposed. With this method, the unwanted harmonics are well suppressed. To effectively reduce the chip area, a miniaturized Marchand Balun based on a folded structure is proposed. The measured results demonstrate good in‐band spectral purity with more than 70 dB suppression of unwanted harmonics. Benefit from the high‐side injection mixing scheme and harmonics suppression method, the presented up‐down converter achieves a dynamic power range of −100 to −5 dBm with a conversion loss of 10 dB. The implemented RF up‐down converter occupies only 0.9 × 2.7 mm2 in size, with a power consumption of 400 mW under 4‐V supply.
In this paper, a 24.25–30 GHz fully integrated radio frequency (RF) up‐down converter with harmonic distortions rejection for 5G millimeter wave radio channel emulator applications is proposed and ...implemented in a 0.1‐μm GaAs pseudomorphic high‐electron‐mobility transistor technology. The RF up‐down converter integrates a frequency doubling amplifier chain local oscillator, a harmonic suppression mixer, and three frequency selective filters for unwanted harmonics suppression. To prevent the unwanted harmonics from leaking into the RF band, a higher sideband and high‐intermediate frequency mixer core with harmonic suppression filters is proposed. With this method, the unwanted harmonics are well suppressed. To effectively reduce the chip area, a miniaturized Marchand Balun based on a folded structure is proposed. The measured results demonstrate good in‐band spectral purity with more than 70 dB suppression of unwanted harmonics. Benefit from the high‐side injection mixing scheme and harmonics suppression method, the presented up‐down converter achieves a dynamic power range of −100 to −5 dBm with a conversion loss of 10 dB. The implemented RF up‐down converter occupies only 0.9 × 2.7 mm2 in size, with a power consumption of 400 mW under 4‐V supply.
Among women who have participated in group-based education about the pelvic floor, what are their perceptions of the program and the group format?
Exploratory longitudinal qualitative study.
...Community-dwelling women aged ≥ 18 years who participated in three or four sessions of pelvic floor education in a group format at a university clinic.
Semi-structured group or individual interviews were conducted at three time points: 1 week, 3 months and ≥ 5 months after the education activity. Data were inductively content analysed and independently coded, with iterative theme development.
Women considered the content and delivery appropriate and useful. New knowledge was assimilated and shared with others, and many tried to adopt pelvic floor muscle training in daily life. The women felt that the education sessions might benefit other women, with and without pelvic floor dysfunction symptoms, and that such education would ideally be more widely available. A perception of the value of the education persisted over time, even though maintenance of some health-promoting behaviours, such as pelvic floor muscle training, decreased.
The pelvic floor group education sessions appeared to fulfil the purpose of increasing knowledge about pelvic floor (dys)function and applying this in daily life. Overall, the participants, who had completed three or four of the four sessions, found the program to be useful. A unique feature of this study was longitudinal data collection and it seemed that the perception of value persisted over time.
In this paper, the terahertz (THz) radiation based on the graphene is studied by theoretical analysis and particle-in-cell (PIC) simulation. We present the transition radiation (TR) of the charged ...particle traversing a monoatomic graphene layer under arbitrary incidence. By theoretical analysis, we find strongly tunable effects of the radiation field distribution related to the electron’s incident angle, substrate permittivity and graphene conductivity. In the case of the normal incidence, the transition radiation exhibits strong symmetry and considerably more intensive than that at oblique incidence. Furthermore, the plasmon and radiation are simulated by a PIC code with the method of equivalent permittivity to deal graphene. With the PIC code, we observe the spatial–temporal dynamics of plasmon and transition radiation from graphene. Meanwhile, the PIC simulation results of radiation are in good agreement with those by theoretical analysis.
Graphic Abstract
Dengue is endemic in Brazil, and several Brazilian cities are affected by frequent seasonal outbreaks of the disease. During the outbreaks the possibility of transfusion-transmitted dengue (TTD) is ...increased, mainly by the presence of asymptomatic or oligosymptomatic infections in eligible blood donors. The retrospective assessment of anti-DENV IgM and NS1 seroprevalence during a given time interval may indicate the need for measures for the previous screening of DENV infection in blood donors. In this context, we performed retrospective screening for anti-DENV IgM and NS1 in blood donors from the Federal District of Brazil during the early outbreak that occurred in 2019, the largest outbreak in recent years. In total, 450 blood donations were screened for anti-DENV IgM and DENV NS1 using commercial enzyme-linked immunosorbent assay kits (Panbio Dengue IgM Capture ELISA and Platelia Dengue NS1 Ag, respectively). Among the tested plasma samples, 16 % (72/450) presented anti-DENV IgM; no samples presented DENV NS1. Despite the apparent absence of antigenaemia in tested blood donations, the high prevalence of anti-DENV IgM highlights the importance of DENV screening in blood donors, principally during outbreak periods.
In this paper, an on-chip aperture antenna in InP (indium phosphide) technology is proposed for terahertz transceivers. Terahertz on-chip antennas are often directly connected to the amplifier, and ...the bulky substrate of active circuits affects the impedance and radiation characteristics of the antenna. In order to obtain robust antenna performances against the uncertain chip size of the active circuits and simultaneously enhance the gain and radiation efficiency, through substrate vias (TSVs) are utilized to form the quasi- substrate integrated waveguide (SIW) cavity. Furthermore, a dual-mode aperture antenna with the quasi-SIW cavity is proposed, and the high-order mode of the substrate integrated cavity is introduced in proximity to the aperture mode to broaden the impedance bandwidth. The non-broadside radiation pattern of the even-TM120 mode is successfully reshaped by the radiating apertures. Then, a custom-designed ground package is analyzed to fix the chip and further improve the broadside gain. Finally, the proposed antenna is fabricated and measured. Benefiting from the techniques proposed above, a competitive gain of ~8.0 dBi is obtained.
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