Highly sensitive FET sensors for cadmium detection in one drop of human serum with a hand-held device and investigation of the sensing mechanism

As the heavy metal contamination is becoming worse, monitoring the heavy metal content in water or human body gets more and more important. In this research, a cadmium ion-selective field effect transistor (Cd-ISFET) for rapidly detecting cadmium ions has been developed and the mechanism of the sensor is also investigated in depth. Our Cd-ISFET sensor exhibits high sensitivity beyond the ideal Nernst sensitivity, wide dynamic range, low detection limit (∼10⁻¹¹M), which is comparable with inductively coupled plasma mass spectrometry, and easy operation enabling people to detect cadmium ion by themselves. From the analysis of electrical measurement results, this Cd-ISFET is preferred to operate at the bias with the maximum transconductance of the FET to enhance the sensor signal. The AC impedance measurement is carried out to directly investigate the mechanism of an ion-selective membrane (ISM). From impedance results, the real part of the total impedance, which is the resistance, was shown to dominate the sensor signal. The potential drop across the ISM is caused by the heavy metal ion in the membrane, which is employed to the gate of the FET via an extended gate electrode. Cadmium ion detection in one drop of human serum with this sensor was demonstrated. This cost-effective and highly sensitive sensor is promising and can be used by anyone and anywhere to prevent people from cadmium poisoning.     

Identifying missing relevant patent citation links by using bibliographic coupling in LED illuminating technology

This study uses bibliographic coupling to identify missing relevant patent links, in order to construct a comprehensive citation network. Missing citation links can be added by taking the missing relevant patent links into account. The Pareto principle is used to determine the threshold of bibliographic coupling strength, in order to identify the missing relevant patent links. Comparisons between the original patent citation network and the comprehensive patent citation network with the missing relevant patent links are illustrated at both the patent and assignee levels. Light emitting diode (LED) illuminating technology is chosen as the case study. The relationships between the patents and the assignees are obviously enhanced after adding the missing relevant patent links. The results show that the growth rates on both the total number and the average number of links have apparently improved at the patent level. At the assignee level, the number of linked assignees and the average number of links between two assignees are increased. The differences between the two citation networks are further examined by means of the Freeman vertex betweenness centrality and Johnson's hierarchical clustering. The patents with more new links to other patents have distinct results in terms of the Freeman vertex betweenness centrality. The enhancement of links among patents also results in different clustering.     

Assessing web services of emerging economies in an Eastern country — Taiwan's e-government

Accessibility of much country-level information and many web services, originating from governments are a global standard. The governments of emerging economies in the eastern countries especially need to adopt, without undue delay, the advanced technologies for providing better web services to their citizens. However, consideration and evaluation of the effectiveness and efficiency of governments' web services is currently lacking in previous literature. Thus, this study first adopts a computational approach suggested in the literature to measure the effectiveness of Taiwan's established, city- and county-level (25 cities and counties, and 1411 governmental units) governments' websites. Then, by considering the IT-related input and output resources as suggested by the experts of e-government during several in-depth interviews, data envelopment analysis (DEA) evaluates the efficiency of Taiwan's governmental web services. This study reveals that the well-developed web services provided by Taiwan's government are apparent in two geographically dispersed cities (north and south) and one county in the northern region of Taiwan. In addition, six cities and counties appear to be ineffective and inefficient in providing web services to Taiwan's citizens due to their geographical remoteness from the capital and small regional populations. An additional finding confirms the significant effect of population size on Taiwanese services for e-government in each city and county. Finally, this study suggests applying more attention to website designs for different levels or regions of governments and building alternative communication channels for citizens with different backgrounds. Consequently, providing citizens' most-requested services becomes easier, and the resources' distribution becomes effective and efficient for those in different geographical locations. This study's findings represent a reference for providing better electronic publically accessible services, and a benchmark for scholars conducting further research in this area.     

Women’s Involvement in Educational Psychology Journals from 1976 to 2004

Previously, Robinson, McKay, Katayama, and Fan (1998) examined women’s involvement in six educational psychology journals (American Educational Research Journal, Contemporary Educational Psychology, Educational Psychologist, Educational Psychology Review, Journal of Experimental Education, and Journal of Educational Psychology) from 1976 to 1996 and found that although women made gains as authors and editorial board members, they remained underrepresented as editors. In this Reflections on the Field article, we compare the Robinson et al. data with our more recent data. We found that from 1996 to 2004, the percentage of women members in education and psychology organizations has risen. Meanwhile, the percentage of women authors has remained stable; the percentage of women editorial board members has risen slightly; and the percentage of women editors has risen dramatically. We also found that the percentage of women authors and editorial board members lags slightly behind what would be expected based on organizational membership percentages for women. On the other hand, there are now more female editors than would be expected.     

Stretching DNA by electric field and flow field in microfluidic devices: An experimental validation to the devices designed with computer simulations

We examined the performance of three microfluidic devices for stretching DNA. The first device is a microchannel with a contraction, and the remaining two are the modifications to the first. The modified designs were made with the help of computer simulations [C. C. Hsieh and T. H. Lin, Biomicrofluidics 5(4), 044106 (2011) and C. C. Hsieh, T. H. Lin, and C. D. Huang, Biomicrofluidics 6, 044105 (2012)] and they were optimized for operating with electric field. In our experiments, we first used DC electric field to stretch DNA. However, the experimental results were not even in qualitative agreement with our simulations. More detailed investigation revealed that DNA molecules adopt a globular conformation in high DC field and therefore become more difficult to stretch. Owing to the similarity between flow field and electric field, we turned to use flow field to stretch DNA with the same devices. The evolution patterns of DNA conformation in flow field were found qualitatively the same as our prediction based on electric field. We analyzed the maximum values, the evolution and the distributions of DNA extension at different Deborah number in each device. We found that the shear and the hydrodynamic interaction have significant influence on the performance of the devices.     

The effects of repeated maximal voluntary isokinetic eccentric exercise on recovery from muscle damage

This study investigated whether performing repeated bouts of maximal voluntary isokinetic eccentric exercise (MAX1) on 3 (MAX3) and 6 days (MAX6) after the initial bout would produce significant changes in the indirect markers of muscle damage and total work. A secondary purpose was to determine whether participants' psychological maximal effort was equivalent to the physiological maximal effort during muscle soreness. Male university students were assigned randomly to a control group (n = 12) and a group that repeated the exercise (EX; n = 12). The MAX1 was 3 x 10 repetitions of the nondominant elbow flexors on the Cybex 6000 system at a speed of 60 deg/s. The EX group performed the same exercise 3 days and 6 days after MAX1. The range of motion and maximal isometric force (MIF), muscle soreness index, plasma creatine kinase, and glutamic-oxaloacetate transaminase activities were measured before and every 24 hr for 9 days after MAX1 for both groups. MIF was also assessed once before and immediately after each MAX for the EX group. There were no significant changes (p > .05) between the groups for all criterion measures, except for total amount of work (p < .05). It is concluded that strenuous voluntary isokinetic eccentric exercise performed with damaged muscles does not appear to exacerbate damage or influence the recovery process. Although individuals could perform repeated MAXs, the total work performed was significantly reduced. This has practical implications in strength training for coaches and athletes during muscle damage.     

Modulating chemotaxis of lung cancer cells by using electric fields in a microfluidic device

We employed direct-current electric fields (dcEFs) to modulate the chemotaxis of lung cancer cells in a microfluidic cell culture device that incorporates both stable concentration gradients and dcEFs. We found that the chemotaxis induced by a 0.5 μM/mm concentration gradient of epidermal growth factor can be nearly compensated by a 360 mV/mm dcEF. When the effect of chemical stimulation was balanced by the electrical drive, the cells migrated randomly, and the path lengths were largely reduced. We also demonstrated electrically modulated chemotaxis of two types of lung cancer cells with opposite directions of electrotaxis in this device.     

An integrated actuating and sensing system for light-addressable potentiometric sensor (LAPS) and light-actuated AC electroosmosis (LACE) operation

To develop a lab on a chip (LOC) integrated with both sensor and actuator functions, a novel two-in-one system based on optical-driven manipulation and sensing in a microfluidics setup based on a hydrogenated amorphous silicon (a-Si:H) layer on an indium tin oxide/glass is first realized. A high-intensity discharge xenon lamp functioned as the light source, a chopper functioned as the modulated illumination for a certain frequency, and a self-designed optical path projected on the digital micromirror device controlled by the digital light processing module was established as the illumination input signal with the ability of dynamic movement of projected patterns. For light-addressable potentiometric sensor (LAPS) operation, alternating current (AC)-modulated illumination with a frequency of 800 Hz can be generated by the rotation speed of the chopper for photocurrent vs bias voltage characterization. The pH sensitivity, drift coefficient, and hysteresis width of the Si₃N₄ LAPS are 52.8 mV/pH, −3.2 mV/h, and 10.5 mV, respectively, which are comparable to the results from the conventional setup. With an identical two-in-one system, direct current illumination without chopper rotation and an AC bias voltage can be provided to an a-Si:H chip with a manipulation speed of 20 μm/s for magnetic beads with a diameter of 1 μm. The collection of magnetic beads by this light-actuated AC electroosmosis (LACE) operation at a frequency of 10 kHz can be easily realized. A fully customized design of an illumination path with less decay can be suggested to obtain a high efficiency of manipulation and a high signal-to-noise ratio of sensing. With this proposed setup, a potential LOC system based on LACE and LAPS is verified with the integration of a sensor and an actuator in a microfluidics setup for future point-of-care testing applications.