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Background/Purpose: To examine ethnic disparity in prevalence and associated factors of myopia in adolescents using the Unites States National Health and Nutrition Examination Survey (NHANES) dataset. Methods: Participants who were aged 12–19 years were included from NHANES (1999–2008). Logistic regression analyses were applied to identify risk factors associated with myopia after stratification by race. Results: A total of 9,960 participants were included in the prevalence analysis, and 6,571 in the risk factor analysis. Other race (excluded Mexican American, other Hispanic, non-Hispanic white, non-Hispanic black) participants had the highest frequency of myopia (42.77%). Multivariate analyses of the whole population suggested that the odds of myopia were significantly lower in participants with household smokers (odds ratio [OR] = 0.79, 95% confidence interval [CI]: 0.66–0.97), and significantly greater in Mexican American race (OR = 1.28, 95% CI: 1.01–1.62), other Hispanic (OR = 1.79, 95% CI: 1.10–2.92) and in participants with senior high school graduate education (OR = 1.79, 95% CI: 1.01–3.18), watched 2 hours of television daily (OR = 1.27, 95% CI: 1.02–1.59), used the computer for 1 hour daily (OR = 1.276, 95% CI: 1.02–1.57). When examined by race/ethnicity, 1 hour of computer use increased the odds of myopia in the non-Hispanic White group, in Mexican Americans a higher family poverty income ratio and 2 hours of television time was associated with myopia, and in the Other Hispanic group, a higher family poverty income ratio was associated with myopia, while males and those with a higher sugar had a lower risk of myopia. Conclusion: Risk factors for myopia vary with race/ethnicity. Keywords: Adolescent, Myopia, Racial disparity, Risk factor, NHANES

Nanofibrous biomaterials fabricated by electrospinning attract increasing attention. However, electrospun nanofibers are stacked tightly, thus restricting cell infiltration and nutrient supply. To overcome this drawback, we developed three types of cytocompatible nanofiber membranes, namely (1) electrospun chitosan/gelatin/PEO (CGP) composite membrane, (2) co-electrospun CGP/E membrane containing CGP and Eudragit (E) nanofibers, (3) CGP (E removed) membrane which was obtained by selective removal of E nanofibers from CGP/E membrane. The permeability of albumin through CGP, CGP/E, and CGP (E removed) nanofiber membranes increased from 1.50 × 10−11 to 6.19 × 10−11 and further to 15.3 × 10−11 m2/s, respectively. Hence, incorporating large-diameter (space-forming) E nanofibers with CGP nanofibers enhanced the permeability of CGP/E membrane. Moreover, selectively removing E nanofibers from CGP/E membrane further enlarged pore size and created more permeable CGP (E removed) membrane. Membrane strength and stability were reinforced by crosslinking with glutaraldehyde for 2.5 h. To verify our approach, stem cells (KP-hMSCs) were covered by CGP (E removed) or CGP membrane and cultured for 7 days. The cell density underneath CGP (E removed) membrane was about 1.7 times of that underneath CGP membrane, indicating that improved cell growth (proliferation) occurred under CGP (E removed) membrane. Therefore, our approach to create more permeable nanofiber membranes for better cell growth is successful and can be utilized for fabricating various nanofibrous biomaterials.

This study analyzed site effects including PGA and empirical transfer functions at 15 selected surface–downhole stations by using ground motion recordings of earthquakes with ML > 4 during 2012 and 2013 in Taiwan. In addition, we used all strong motion recordings of four large earthquakes (ML > 6) to generate intensity distribution maps and assess the differences in magnitude at the surface and downhole. The site amplification factors of the PGA were calculated using the ratio between the surface and downhole recordings. The mean PGA amplification factors ranged from 2 to an exaggerated value of 20 at different stations. In addition, the power law relationships between the PGAs at the surface and downhole were evaluated to understand how amplification varies as PGA increases. Strong ground motions with and without site effects throughout Taiwan could be observed by comparing intensity distribution maps generated using the surface and downhole accelerations from four large earthquakes with magnitudes > 6. Empirical transfer functions derived using the single-station and two-station methods at the same stations showed comparable dominant frequencies and amplification factors; however, the empirical transfer function derived using the two-station method showed clearer resonance peaks, not only at fundamental frequencies but also at higher mode resonance frequencies. The HHSR and the HVSR were highly similar, particularly at medium frequencies. This finding indicates that the HVSR can be used instead of the HHSR when only the surface recording is available. Moreover, the local magnitudes calculated using surface recordings were higher than those calculated using downhole recordings. The differences are attributed to the amplification caused by the sedimentary layers and resultant in 0.36, 0.46 and 0.49 on average for events with ML of > 6, 5–6, and 4–5. Furthermore, HHSRs at 5–10 Hz and 1.1–1.7 Hz were strongly correlated with PGA amplifications and ML differences, respectively.

Novel physical properties not seen in their individual layers are obtained from stacked layers of materials. In this report, using the first-principles calculations, we study the electronic band structures of heterostructures composed of graphitic (graphene-like) bilayers of g-ZnO/ZnX (X = S, Se, and Te) semiconductors. The g-ZnO layer is largely planar, but the ZnX layer is somewhat corrugated. Our calculations reveal on the stable formations of a type-II band alignment in bilayers with an AB stacking order of OZnO-ZnZnX and ZnZnO-XZnX. The optical bandgaps are much lowered as compared to the monolayers of ZnO and ZnX constituents, with the conduction band contributed by g-ZnO and valence band by ZnX. There is a quadratic dependence of the bandgap on the external electric biases applied in perpendicular to the interface. This nonlinearity manifests an superposed effect of an interlayer orbital hybridization and associated charge transferring, along with the coexistence of an electric dipole and a quadrupole. There is an overall charge transfer of valence electrons from the ZnX layer to the g-ZnO layer, leading to a pair of highly charge polarized surfaces along with a large built-in potential. The already lowered bandgaps further change with the external bias. This tunability of Eg for g-ZnO/ZnX bilayer heterostructures holds promises for optoelectronic applications covering a wider spectral range of the solar spectrum.

On February 12, 2014, an ML 4.2 earthquake (named 0212 EQ) occurred at the Tatun Volcano Group (TVG) in northern Taiwan. Seismic data from both the regional broadband array in Taiwan and a local dense seismic network in the TVG indicate that the 0212 EQ was located at a depth of 4.3 km near Shamoshan, one of the latest eruptive units in the TVG. Referring to the aftershocks surrounding the 0212 EQ, we further found that (1) they formed a linear seismic zone dipping ∼50° towards the southeast to reach the Shanchiao Fault that cuts through the TVG, (2) focal mechanism of more than half of the larger aftershocks (MD ≥ 1.5) matched this linear seismic zone for a normal faulting, and (3) the seismic b-value was calculated to be 3.55. They are used to delineate the geometry of the Shanchiao Fault at the upper crust and to infer that localized geothermal fluid might have affected the activity of aftershocks as manifested by the very high seismic b-value. The strongly compensated linear vector dipole of the centroid moment tensor suggests the 0212 EQ had a non-double-couple source resulted from the gravitational collapse. Thus, we conclude that the 0212 EQ was a combined synergistic effect of a collapsed reservoir filled with volcanic fluids and faulting activities along the Shanchiao Fault.

The damping ratio is an important index used in soil nonlinearity studies and is mostly proportional to the shear strain increase. Previous researches indicated a frequency-independent damping in most cases. In this study, frequency-dependent damping was introduced from frequency-dependent Q calculated through the spectral ratio method of near-surface structures using the power spectrum of strong motion records in the Strong Motion Array in Taiwan Phase I (SMART1). The dense SMART1 recorded significant strong motions in the 1980s, which can be used to identify soil nonlinearity at near surfaces. A 40%–50% increase in frequency-dependent damping for SMART1 was identified, with strain increasing from 0.01% to 0.1% in near-surface regions. A large damping was also found in the shallow sediments with mean Vs below 600 m/s on the topmost 500 m layers in the SMART1 database at a frequency range of 3–8 Hz, which is independent of the magnitude scaling or near-field travel distance scaling relations.

Long-period pulse-like strong ground motions were recorded near the Milun fault and caused serious building damages in the Hualien City during the main shock of the 2018 Hualien, Taiwan, earthquake. In this paper, questionnaire survey on feeling of shaking, indoor damages, structural, and nonstructural damages to high-rise reinforced concrete residential buildings were analyzed by three building groups according to the positions to the Milun fault and different site conditions. Relationships between the results of questionnaire survey on building damages and characteristics of strong ground motions were studied. Furthermore, a characterized seismic source model was proposed to elucidate the generation mechanism of near-fault long-period strong ground motions. In this model, a shallow strong motion generation area (SMGA7) in the south part of Milun fault with rise-time of 2.6 s contributed to the long-period pulse-like strong ground motions. Besides, a deep SMGA (SMGA8) under the SMGA7 with rise-time of 1.2 s also contributed to the strong ground motions. Using this model, strong ground motions at the sites of buildings for questionnaire survey were synthesized. Because of the directivity effects, amplitudes of ground motions were increased from north to south along the Milun fault, which can explain the serious building damages at the buildings located at the southwest to the Milun fault. The reasons of building damages were also examined from the aspect of predominant periods of ground sites and fundamental periods of buildings, which were extracted from microtremor measurement. Damages at the buildings located on the central part of the hanging wall with relatively good site condition were the lightest for almost all the surveyed items. Pulses with period in the range of 1 s–2 s which were generated by the SMGA8 and amplified by the near surface layers are considered to be responsible for building damages.

In this study, an empirical transfer function (ETF), which is the spectrum difference in Fourier amplitude spectra between observed strong ground motion and synthetic motion obtained by a stochastic point-source simulation technique, is constructed for the Taipei Basin, Taiwan. The basis stochastic point-source simulations can be treated as reference rock site conditions in order to consider site effects. The parameters of the stochastic point-source approach related to source and path effects are collected from previous well-verified studies. A database of shallow, small-magnitude earthquakes is selected to construct the ETFs so that the point-source approach for synthetic motions might be more widely applicable. The high-frequency synthetic motion obtained from the ETF procedure is site-corrected in the strong site-response area of the Taipei Basin. The site-response characteristics of the ETF show similar responses as in previous studies, which indicates that the base synthetic model is suitable for the reference rock conditions in the Taipei Basin. The dominant frequency contour corresponds to the shape of the bottom of the geological basement (the top of the Tertiary period), which is the Sungshan formation. Two clear high-amplification areas are identified in the deepest region of the Sungshan formation, as shown by an amplification contour of 0.5 Hz. Meanwhile, a high-amplification area was shifted to the basin’s edge, as shown by an amplification contour of 2.0 Hz. Three target earthquakes with different kinds of source conditions, including shallow small-magnitude events, shallow and relatively large-magnitude events, and deep small-magnitude events relative to the ETF database, are tested to verify site correction. The results indicate that ETF-based site correction is effective for shallow earthquakes, even those with higher magnitudes, but is not suitable for deep earthquakes. Finally, one of the most significant shallow large-magnitude earthquakes (the 1999 Chi-Chi earthquake in Taiwan) is verified in this study. A finite fault stochastic simulation technique is applied, owing to the complexity of the fault rupture process for the Chi-Chi earthquake, and the ETF-based site-correction function is multiplied to obtain a precise simulation of high-frequency (up to 10 Hz) strong motions. The high-frequency prediction has good agreement in both time and frequency domain in this study, and the prediction level is the same as that predicted by the site-corrected ground motion prediction equation.

This study demonstrates the emission enhancement of Al 3+ co-doped SrZn 2 (PO 4 ) 2 :Eu 2+ ,Mn 2+ phosphors. The crystallinity and emission mechanism were investigated, and the results indicate that co-doping with Al 3+ increased the atomic concentrations of Sr and P and induced the formation of Al–O bonds. The formation of P–O–P bonds was also facilitated. Furthermore, the crystal field strength of Mn 2+ –O 2- was decreased, and the reduction reaction of Eu 3+ to Eu 2+ was promoted. Photoluminescence measurements revealed a 2.83-fold enhancement of the Eu 2+ emission upon co-doping with 0.46 mol of Al 3+ . However, the Mn 2+ emission decreased and was blue-shifted because of the increased bond length of Mn 2+ –O 2- and decreased ligand field around Mn 2+ . The phosphor decay time was also reduced with increasing Al 3+ concentration.

The influence of In 3+ doping on the binding energy of ions and the energy transfer mechanism of white SrZn 2 (PO 4 ) 2 :Eu 2+ ,Mn 2+ phosphor was investigated. The ligand fields around Sr 2+ and Mn 2+ varied with different kinds of doped ions, while those around Zn 2+ and Eu 2+ remained stable. Doping with In 3+ created traps of charged species and clustered pairs in the phosphor. These traps captured excited carriers, leading to a decrease in energy transfer from Eu 2+ to Mn 2+ and a decline in Mn 2+ emission. However, carriers stored temporarily in traps then migrated to Eu 2+ to yield an enhanced Eu 2+ emission. The phosphor emission was blue-shifted by the increase in In 3+ concentration. Maximum Eu 2+ energy absorption and emission were obtained when doped with 12 mol% of In 3+ . The decay time of the phosphor was 11.74 ms.

In this study, microtremor array measurements were conducted at 45 sites in the Western Plain of Taiwan. The arrays were approximately 30 m or 60 m in radius, depending on the site. The maximum-likelihood frequency–wavenumber method was adopted to obtain the phase velocities of Rayleigh waves, and then a genetic algorithm technique based on an inversion scheme of the fundamental mode of the Rayleigh waves’ dispersion curves was applied to calculate a preliminary S-wave velocity (Vs) profile at each site. Because a layer of thick sediment covers the bedrock in the Western Plain of Taiwan, microtremor arrays in this size range cannot estimate the structure of the entire sediment. Therefore, this study implemented further inversion of the horizontal-to-vertical spectral ratios of the microtremors to estimate the deeper structures up to the bedrock of Vs greater than 1000 m/s. Previously logged velocity profiles for different depths at or near our study sites were collected and compared with the Vs profiles derived from our microtremor array measurements; the results were found to be highly comparable. Therefore, we could delineate the depth distributions for the layer depths for Vs = 600 m/s and 1000 m/s in this region. The depth for Vs = 600 m/s is approximately 50 m in the piedmont area and approximately 300 m at the coastline; moreover, the depths for Vs = 1000 m/s increase from 200 m in the piedmont area to approximately 1000 m at the coastline. The depths for Vs = 1.0 km/s (Z1.0), which is an important parameter that accounts for the basin effect in recent ground motion prediction equations, are consequently available at the study sites. The distribution of Z1.0 as a function of Vs30 indicates higher similarity to that in Japan than in the San Francisco Bay area.

Compound semiconductors doped with magnetically active transition metals (TM) are actively pursued for semiconductor spintronics. Herein we report that delta doping (δ-doping) has been used to incorporate manganese (Mn) into the gallium nitride (GaN) matrix resulting in phase pure highly crystalline heteroepitaxial thin films of (Ga,Mn)N on c-plane sapphire (Al2O3) by plasma-assisted molecular beam epitaxy. Magnetotransport measurements reveal the anomalous Hall effect (AHE) while magnetic measurements show the existence of ferromagnetic ordering. Density functional theory calculations show that δ-doping of Mn atom enables exchange interactions between the Mn 3d states and N 2p states thereby resulting in spin polarized holes in the valence band giving rise to observed AHE and ferromagnetism. This work opens new avenues for incorporating spin polarized carriers in III-nitrides based semiconductors by creating magnetically active Mn layers in heterostructures for spintronics applications.

The energy transfer mechanism between Tm 3+ and Eu 3+ ions in the phosphate phosphor was investigated. The addition of Eu facilitated the incorporation of O atoms into the LaPO 4 :Tm,Eu phosphor lattice, which induced changes in its ligand field and energy absorption. Excitation energy was transferred from Tm 3+ to Eu 3+ ions by the mechanism of dipole–dipole interaction. The increase in Eu concentration increased the probability of energy transfer between Tm 3+ and Eu 3+ as well as the electron transition probabilities in Eu 3+ ; a color-tunable emission was observed through variation in the Eu concentration. The highest energy transfer efficiency of Tm 3+ –Eu 3+ was approximately 93%. The critical distance, for energy transfer, between Tm 3+ and Eu 3+ , was 14.5 A. The luminescence of the phosphor declined with a double-exponential mechanism. The decay time decreased as the Eu doping concentration was increased.

When the phosphor LaPO4:Tm was coated with carbon nanotubes (CNTs), carbon atoms were diffused into the phosphor lattice. Binding energy of La 3d and C 1s were not shifted by CNT coating, while that of O 1s was lowered slightly as a result of the formation of C O and C O bonds on the phosphor surface. CNT coating increased the atomic concentrations of O and C by 27.4% and 9%, respectively. Photoluminescence intensity decreased significantly, by 52%, when CNT concentration of 1.5 wt% was coated. This is attributed to covering the phosphor with black CNTs/carbons and the formation of C O and C O bonds on the phosphor surface. Conversely, cathodoluminescence (CL) intensity was improved by a factor of 3.86 when 1.25 wt% of CNTs was coated, attributing to improved conductivity, reduced charging, and increased CL excitation probability of the phosphor. The influence of CNT coating on the luminescence of LaPO4:Tm was compared with that of LaPO4:Eu phosphor. Blue CL was observed from LaPO4:Tm, it is potential for field emission lamp application.

Novel chitosan/pectin/gum Arabic polyelectrolyte complex (PEC) solutions and membranes with various compositions were prepared for biomedical applications. The appearance of the PEC solutions, either clear or turbid, was process-dependent and depended on how the three components were dissolved and mixed. The addition of gum Arabic to the chitosan and pectin significantly decreased the viscosities of the resultant PEC solutions due to the formation of globe-like microstructures that was accompanied by network-like microstructures and other molecular entanglements. The mechanical strength and hydrophilicity of the PEC membranes manufactured from the PEC solutions, especially for a weight ratio of 84/8/8 (chitosan/pectin/gum Arabic), were enhanced compared to pure chitosan membranes. Moreover, the use of the 84/8/8 PEC membranes as a drug carrier exhibited steady and fairly complete release of a drug (insulin) for 6h. Based on these promising results, the chitosan/pectin/gum Arabic PEC membranes have great potential in controlled drug release applications.

This study extracted some P-wave features from the first few seconds of vertical ground acceleration of a single station. These features include the predominant period, peak acceleration amplitude, peak velocity amplitude, peak displacement amplitude, cumulative absolute velocity and integral of the squared velocity. The support vector regression was employed to establish a regression model which can predict the peak ground acceleration according to these features. Some representative earthquake records of the Taiwan Strong Motion Instrumentation Program from 1992 to 2006 were used to train and validate the support vector regression model. Then the constructed model was tested using the whole earthquake records of the same period as well as the 2010 Kaohsiung earthquake with 6.4 M L . The effects on the performance of the regression models using different P-wave features and different length of time window to extract these features are studied. The results illustrated that, if the first 3 s of the vertical ground acceleration was used, the standard deviation of the predicted peak ground acceleration error of the whole tested 15-years earthquake records is 20.89 gal.The length of time window could be shortened, e.g. 1 s, and the prediction error is slightly sacrificed, in order to prolong the lead-time before destructive S-waves reaches.

The Engineering Geological Database for TSMIP (EGDT), the Taiwan Strong Motion Instrumentation Program, has been under construction by the National Center for Research on Earthquake Engineering and the Central Weather Bureau in Taiwan since 2000. Site characterization, comprising surface investigations and logging measurements, was carried out throughout the project. We provide a set of specifications and a description to help users understand the subject matter of the database. EGDT contains 469 surveyed stations, 439 of which were drilled and the logging measurements completed. Of these, 385 had logging data reaching at least 30 m, and we used these to examine and determine the most accurate extrapolation of Vs30 (the average S-wave velocity of the top 30 m of strata) for the other 54 stations with velocity profiles less than 30 m. The chosen method assumed that the bottom velocity is identical from the actual depth of the hole to a distance of 30 m, that is, the Bottom Constant Velocity (BCV) method. In order to utilize other existing boreholes which have only N values but no velocities in the future, the empirical S-wave velocity equations for seven different regions and the whole of Taiwan were evaluated by a multivariable analysis. Henceforth, for those existing boreholes which have an N profile less than 30 m, the S-wave velocity profile can first be calculated by empirical S-wave velocity equations, and then Vs30 can be estimated by reliable extrapolation. Some other studies of site classifications of TSMIP stations were compared with our results to demonstrate the necessity of reclassification. Ultimately, the Vs30 values of the 439 drilled free-field TSMIP stations were derived and the new site classification was achieved according to the Vs30-based provisions of the National Earthquake Hazards Reduction Program.

The shear wave velocity of shallow sediments is very important in seismic wave amplification and thus Vs 30 is a well-known parameter for site classification. Based on the relationship between Vs and soil indexes, the empirical regression equations were evaluated using more than 600 data sets from the Ilan area and the Taipei Basin. Multivariable analysis, which can increase the accuracy of regression equations, was used in this study. Three extrapolations were compared, and then the most accurate bottom-constant extrapolation was adopted to estimate Vs 30 at 16 boreholes, none of which reached a depth of 30 m. Ultimately Vs 30 was derived for 110 free-field strong motion stations, and the stations in northeastern Taiwan were reclassified according to the Vs 30-based NEHRP provisions. Regression equations of Vs and the extrapolation of Vs 30 were also applied to boreholes with only N -values and corresponding depths of less than 30 m for assessing the Vs 30 and NEHRP class.