Effects of 3‐D microwell culture on initial fate specification in human embryonic stem cells

Several studies have demonstrated that three‐dimensional (3‐D) culture systems influence human embryonic stem cell (hESC) phenotypes and fate choices. However, the effect that these microenvironmental changes have on signaling pathways governing hESC behaviors is not well understood. Here, a 3‐D microwell array was used to investigate differences in activation of developmental pathways between 2‐D and 3‐D cultures of both undifferentiated hESCs and hESCs undergoing initial differentiation in embryoid bodies (EBs). An increased induction into mesoderm and endoderm and differences in expression of genes from multiple signaling pathways that regulate development, including Wnt/β‐catenin, TGF‐β superfamily, Notch, and FGF during EB‐mediated differentiation were observed in 3‐D microwells as compared with the 2‐D substrates. In undifferentiated hESCs, differences in epithelial‐mesenchymal transition phenotypes and the TGFβ/BMP pathway between cultures in 3‐D and 2‐D were also observed. These results illustrate that 3‐D culture influences multiple pathways that may regulate the differentiation trajectories of hESCs. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1225–1235, 2014     

Effect of In/Al ratios on structural and optical properties of InAlN films grown on Si(100) by RF-MOMBE

In _x Al_1-x N films were deposited on Si(100) substrate using metal-organic molecular beam epitaxy. We investigated the effect of the trimethylindium/trimethylaluminum (TMIn/TMAl) flow ratios on the structural, morphological, and optical properties of In _x Al_1-x N films. Surface morphologies and microstructure of the In _x Al_1-x N films were measured by atomic force microscopy, scanning electron microscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM), respectively. Optical properties of all films were evaluated using an ultraviolet/visible/infrared (UV/Vis/IR) reflection spectrophotometer. XRD and TEM results indicated that In _x Al_1-x N films were preferentially oriented in the c-axis direction. Besides, the growth rates of In _x Al_1-x N films were measured at around 0.6 μm/h in average. Reflection spectrum shows that the optical absorption of the In _x Al_1-x N films redshifts with an increase in the In composition.     

Advanced Cu chemical displacement technique for SiO2-based electrochemical metallization ReRAM application

This study investigates an advanced copper (Cu) chemical displacement technique (CDT) with varying the chemical displacement time for fabricating Cu/SiO₂-stacked resistive random-access memory (ReRAM). Compared with other Cu deposition methods, this CDT easily controls the interface of the Cu-insulator, the switching layer thickness, and the immunity of the Cu etching process, assisting the 1-transistor-1-ReRAM (1T-1R) structure and system-on-chip integration. The modulated shape of the Cu-SiO₂ interface and the thickness of the SiO₂ layer obtained by CDT-based Cu deposition on SiO₂ were confirmed by scanning electron microscopy and atomic force microscopy. The CDT-fabricated Cu/SiO₂-stacked ReRAM exhibited lower operation voltages and more stable data retention characteristics than the control Cu/SiO₂-stacked sample. As the Cu CDT processing time increased, the forming and set voltages of the CDT-fabricated Cu/SiO₂-stacked ReRAM decreased. Conversely, decreasing the processing time reduced the on-state current and reset voltage while increasing the endurance switching cycle time. Therefore, the switching characteristics were easily modulated by Cu CDT, yielding a high performance electrochemical metallization (ECM)-type ReRAM.     

多條隧道交會段施工監測回饋分析

多條隧道交會段之力學行為係複雜之三向度問题,以三維數值分析程式FLAC3D針對其7條隧洞交會之實際工程案例,模擬其實際挖撐過程,並與佈置於交會段各處斷面監測結果進行比對,以瞭解隧道目前開挖圍岩穩定性,同時進一步預測隧道後續施工行為。分析結果顯示:案例隧道交會段施工互制影響範圍有限,目前隧道大體處於穩定狀態;後續洞台降挖及另一主隧道開挖,在及時支撐情況下,圍岩變形量增加有限,隧道安全應無問题,惟仍應持續進行監測,確實掌握隧道行為。     

Daily intake of TBT, Cu, Zn, Cd and As for fishermen in Taiwan

The consumption of contaminated seafood has been reported as an important route of human exposure to metals in Taiwan. We consider the concentrations of TBT, Cu, Zn, Cd, As, and the consumption of oysters of Taiwanese to be the important information related to public health in Taiwan. Therefore, the aim of this study was to evaluate the public health risks associated with TBT, Cu, Zn, Cd and As from shellfish for the general population and fishermen of Taiwan. In general, TBT concentrations in various oysters ranging from 0.32 to 1.51 microg/g dry wt. varied with sampling locations. The highest TBT, Cu, and Zn geometric mean (GM) concentrations in oysters of 1.51, 1180 and 1567 microg/g dry wt. were obtained from the Hsiangshan coastal area. The values of oyster consumption for fishermen were 94.1 and 250 g/day for typically and maximally exposed individuals, respectively. In particular, the highest intake (250 g/day) from fishermen was almost two times greater than that of the general population (139 g/day). The THQ (target hazard quotient) values of Hsiangshan's fishermen are 3.87 and 20.50 for TBT and Cu for maximally exposed individuals are higher than other oyster culture areas. It is interesting that those consuming oysters from Hsiangshan, Lukang, Taishi caused abnormally high THQs of TBT and other metals (100% over 1.0), and TBT was attributed to only 3-21% of the total THQs in different fishermen of Taiwan. Our results suggest that current environmental levels of TBT and other metals are associated with a significant potential threat to human health for fishermen resident in coastal areas of Taiwan.     

Firefighter Wayfinding in Dark Environments Monitored by RFID

A building on fire is a smoky and dark environment both for firefighters and for civilians trapped inside. The faster firefighters find a way to search for and rescue civilians at a fire scene, the higher the survival rate of those trapped inside. This study presents a discussion on the characteristics of firefighter wayfinding under low visibility. The firefighters who participated in this study underwent testing at a training ground. The participants’ search and wayfinding paths were recorded using radiofrequency identification (RFID) technology. The results revealed that the mean searching time in each room decreased from 135 to 19 s as the firefighters became increasingly familiarized with the task. As expected, data also shows that smaller rooms contributed to shorter searching times. Most participants could manage a maximum of three rooms, with wayfinding confusion manifested after they had searched through the third room. These findings are crucial for the design of fireground strategies and training.     

An ergonomic study of visual optimization by light color managements

Light‐emitting diodes (LEDs) have the advantage of controllable light colors and provide the optimal lighting quality against various color attributes required in different environments. However, from the humanized design point of view, beside satisfying physical demands of people, it is also important to achieve satisfaction. With a good match between the LED lighting equipment and ambient colors, the space imagery that complies with psychological needs of human beings can be found. This is expected to become a new market direction for future lighting. In this study, the LED light source feature of adjustable correlated color temperature is used to match wall colors of typical commercial spaces and for the investigation and analysis of the impact of colors of light sources and environments on human beings. The measures of mental and subjective feelings of a group of people under various circumstances have also been investigated. Multivariate analysis of variance has been conducted on three color temperatures of light sources, six wall colors, and measures of five emotion adjectives, and the correlation between these three variables has been further investigated. © 2014 Wiley Periodicals, Inc. Col Res Appl, 41, 72–84, 2016     

A novel optic disc detection scheme on retinal images

Robust and effective optic disc detection is a necessary processing component in automatic retinal screening systems. In this paper, optic disc localization is achieved by a novel illumination correction operation, and contour segmentation is completed by a supervised gradient vector flow snake (SGVF snake) model. Conventional GVF snake is not sufficient to segment contour due to vessel occlusion and fuzzy disc boundaries. In view of this reason, the SGVF snake is extended in each time of deformation iteration, so that the contour points can be classified and updated according to their corresponding feature information. The classification relies on the feature vector extraction and the statistical information generated from training images. This approach is evaluated by means of two publicly available databases, Digital Retinal Images for Vessel Extraction (DRIVE) database and Structured Analysis of the Retina (STARE) database, of color retinal images. The experimental results show that the overall performance is with 95% correct optic disc localization from the two databases and 91% disc boundaries are correctly segmented by the SGVF snake algorithm.