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BackgroundAdult asthma is phenotypically heterogeneous with unclear aetiology. We aimed to evaluate the potential contribution of environmental exposure and its ensuing response to asthma and its heterogeneity.MethodsEnvironmental risk was evaluated by assessing the records of National Health Insurance Research Database (NHIRD) and residence-based air pollution (particulate matter with diameter less than 2.5 micrometers (PM2.5) and PM2.5-bound polycyclic aromatic hydrocarbons (PAHs)), integrating biomonitoring analysis of environmental pollutants, inflammatory markers and sphingolipid metabolites in case–control populations with mass spectrometry and ELISA. Phenotypic clustering was evaluated by t-distributed stochastic neighbor embedding (t-SNE) integrating 18 clinical and demographic variables.FindingsIn the NHIRD dataset, modest increase in the relative risk with time-lag effect for emergency (N=209 837) and outpatient visits (N=638 538) was observed with increasing levels of PM2.5and PAHs. Biomonitoring analysis revealed a panel of metals and organic pollutants, particularly metal Ni and PAH, posing a significant risk for current asthma (ORs=1.28–3.48) and its severity, correlating with the level of oxidative stress markers, notably Nε-(hexanoyl)-lysine (r=0.108–0.311, p<0.05), but not with the accumulated levels of PM2.5exposure. Further, levels of circulating sphingosine-1-phosphate and ceramide-1-phosphate were found to discriminate asthma (p<0.001 and p<0.05, respectively), correlating with the levels of PAH (r=0.196, p<0.01) and metal exposure (r=0.202–0.323, p<0.05), respectively, and both correlating with circulating inflammatory markers (r=0.186–0.427, p<0.01). Analysis of six phenotypic clusters and those cases with comorbid type 2 diabetes mellitus (T2DM) revealed cluster-selective environmental risks and biosignatures.InterpretationThese results suggest the potential contribution of environmental factors from multiple sources, their ensuing oxidative stress and sphingolipid remodeling to adult asthma and its phenotypic heterogeneity.

ABSTRACTThis paper presents a novel small differentially-fed open-slot antenna for diversity of the operated frequency and circular polarization. The proposed antenna structure, which consists of an L-shaped open slot and two bent feeding lines, provides two separate effective bandwidths. The proposed antenna achieves the operation bandwidths of a global positioning system (GPS) and satellite digital audio radio (SDAR) service system. To excite the even and odd modes for bandwidth enhancement, a rectangular patch was embedded in the vertical segment of the L-shaped open slot, thereby forming a coplanar-waveguide topology. An additional rectangular patch was placed above the open slot to increase the interport isolation performance between the two feeding ports. After optimization, the measurement results indicated that the final open-slot antenna provided −10-dB reflection coefficient (S11) bands from 1.29 to 1.70 GHz for the GPS operation and from 2.09 to 2.56 GHz for the SDAR application. Measured 3 dB axial-ratio bandwidths of the proposed structure were 410 MHz (28.5%) from 1.23 to 1.64 GHz and 430 MHz (18.4%) from 2.12 to 2.55 GHz for right- and left-hand circular polarization, respectively.

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AbstractThis study assessed oxidatively damaged DNA and antioxidant enzyme activity in workers occupational exposure to metal oxides nanomaterials. Exposure to TiO2, SiO2, and ITO resulted in significant lower antioxidant enzymes (glutathione peroxidase and superoxide dismutase) and higher oxidative biomarkers 8-hydroxydeoxyguanosine (8-oxodG) than comparison workers. Statistically significant correlations were noted between plasma and urine 8-oxodG, between white blood cells (WBC) and urine 8-oxodG, and between WBC and plasma 8-oxodG. In addition, there were significant negative correlations between WBC 8-oxodG and SOD and between urinary 8-oxodG and GPx levels. The results showed that urinary 8-oxodG may be considered to be better biomarker.

ABSTRACTDesigns of a miniaturized low-pass filter (LPF) using the slotted-ground-plane resonator are introduced in this paper. The proposed filter consists of a horn-head slot in the ground plane, two modified arc-head resonators, and a parasitic patch connected at the microstrip line. The horn-head slot, which is a modified type of a horn-shaped slot, provides good band-stop characteristics. To enhance rejection performance, a pair of the modified arc-head slot is embedded inside the horn-head resonator to increase additional transmission zeros into frequency characteristics. Furthermore, a parasitically circular patch is added at the microstrip line for frequency reduction and rejection enhancement. The surface current distributions are presented to explain the resonance mechanism. For the proposed LPF, the measured rejection bandwidth over −20 dB is from 1.75 to 12.0 GHz.

AbstractNew techniques of designing a compact coplanar-waveguide (CPW) harmonic-suppressed resonator using the defected ground structure (DGS) resonator with floating or shorting patches are proposed in this paper. Two T-shaped slots as a bandstop resonator are etched in two ground planes of a CPW 50V transmission line. Two rectangular patches are symmetrically placed on the bottom layer of the substrate. The patches modeled as an additional capacitance increase the effective capacitance of the resonator. By tuning the geometrical dimension of the patches, the resonant frequency is lowered. Furthermore, frequency reduction and harmonic suppression are improved by embedding two shorting pins or adding two shorting walls inside the patches. The rejection bandwidth decreases and the quality factor (Q) increases due to enhancement of stored energy in the resonator.

Previous studies demonstrated the presence of unknown direct-acting ethylating agents arising from cigarette smoke. We hypothesized that such agents would also lead to ethylation of guanine in DNA followed by depurination/repair and excretion of N7-ethylguanine (N7-EtG) in urine. In this study, a highly specific and sensitive liquid chromatographic/tandem mass spectrometric (LC/MS/MS) method was firstly developed for measuring urinary N7-EtG. With the use of an isotope internal standard (15N5-N7-EtG) and on-line enrichment techniques, the detection limit of this method was estimated as 0.59 pg/ml (0.33 pmol) on-column. This method was then applied to measure urinary samples obtained from 35 non-smokers and 32 smokers with dietary control. The results showed that the mean urinary levels of N7-EtG were 85.5 ± 105 and 28.1 ± 19.4 pg/mg creatinine for smokers and non-smokers, respectively. Smokers had about three times higher level of N7-EtG than non-smokers (P < 0.005). It was further noted that the urinary level of N7-EtG was significantly associated with cotinine for smokers (r = 0.49, P < 0.005). Taken together, this is the first study that demonstrated the presence of N7-EtG in urine, and that cigarette smoke was highly responsible for the increased urinary excretion of N7-EtG. This non-invasive measurement of urinary N7-EtG would be useful for the surveillance of ethylating agent exposure and its associated cancer risk in the future.

An active microstrip leaky-wave antenna possessing asymmetrically dual-beam scanning capability is demonstrated. An active HEMT up-converter is integrated at the right terminal of the two-terminal feeding microstrip leaky-wave antenna. This approach creates dual-beam asymmetrically scanning radiation patterns. When the right beam is fixed in one position, the other beam can be scanned electronically by varying the IF frequency. The measured results show that when the position of the right beam was fixed (48°), a scanning angle of 22° for the left beam could be achieved as the IF input frequency was varied from 0.7 to 2 GHz (UHF band).

A beam-switchable scanning leaky-wave antenna (LWA) has been developed. This LWA with a two-terminal feeding microstrip line structure is integrated with a single port double throw (SPDT) switch as a control circuit. In dual-beam mode, the scanning angle is steered over a range of 36–64° for the right-hand beam and 144 –116° for the left-hand beam. In one-beam mode, the scanning angle is measured over 20° for the right-hand beam. The measured result shows that we can change from the one-beam mode to the dual-beam mode electronically by controlling the on/off status of an SPDT switch, in contrast to the case for traditional leaky-wave antennas.

An active aperture-coupled leaky-wave antenna (LWA) with excellent dual-beam scanning capability is presented. An X-band varactor-tuned HEMT VCO is integrated on the other plane through an aperture with the LWA. This antenna has the advantages of multi-functionability, interference shielding, and a scanning main beam. The measured main beam in the elevation plane can be continuously scanned for 20° for each beam as the HEMT VCO frequency is varied from 8.97 to 9.5 GHz. An effective isotropic radiation power of 18.89 dBm for the right beam and 19.06 dBm for the left beam is achieved.

We have investigated the effects of rapid thermal annealing on the Si delta-doped GaInP. The spatial localization of carriers was derived and used to determine the diffusion coefficient of Si in GaInP by the capacitance-voltage measurement. We found an unusual mobility change of Si delta-doped GaInP after annealing from Hall-effect measurement. The compensation effect of Si amphoteric property could not be used to explain this behavior. From photoluminescence spectra, it is suggested that the ordered/disordered transformation is the dominate factor for mobility increase after annealing. On the contrary, the degradation of quantum confinement in delta-doped structure by dopant diffusion after annealing is responsible for the decrease of mobility. Therefore, the behavior of mobility could be considered as a competition result of these two mechanisms.

Silicon delta doping in GaInP material has been demonstrated by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) and characterized by Hall-effect and capacitance-voltage (C-V) measurements. The mobility enhancement of delta-doped samples over their corresponding uniformly doped samples was observed. High sheet carrier density of NS=1.21×1013cm-2could be obtained. A sharp carrier distribution profile with the full width at half maximum of 25 Å has been achieved.