Dielectrophoretic manipulation of particles in a modified microfluidic H filter with multi-insulating blocks     

Nuttawut Lewpiriyawong  Chun Yang    Yee Cheong Lam 《Biomicrofluidics》2008,2(3)

The conventional microfluidic H filter is modified with multi-insulating blocks to achieve a flow-through manipulation and separation of microparticles. The device transports particles by exploiting electro-osmosis and electrophoresis, and manipulates particles by utilizing dielectrophoresis (DEP). Polydimethylsiloxane (PDMS) blocks fabricated in the main channel of the PDMS H filter induce a nonuniform electric field, which exerts a negative DEP force on the particles. The use of multi-insulating blocks not only enhances the DEP force generated, but it also increases the controllability of the motion of the particles, facilitating their manipulation and separation. Experiments were conducted to demonstrate the controlled flow direction of particles by adjusting the applied voltages and the separation of particles by size under two different input conditions, namely (i) a dc electric field mode and (ii) a combined ac and dc field mode. Numerical simulations elucidate the electrokinetic and hydrodynamic forces acting on a particle, with theoretically predicted particle trajectories in good agreement with those observed experimentally. In addition, the flow field was obtained experimentally with fluorescent tracer particles using the microparticle image velocimetry (μ-PIV) technique.  相似文献   

Differentiated Curriculum Design: Responding to the Individual and Group Needs of Students with Learning Difficulties with Self‐regulated Learning Strategies     

Winnie Sin Wai Pui 《Support for Learning》2016,31(4):329-346

The purpose of this study was to explore special educational curriculum design at senior secondary school level and whether this helps to enhance the academic attainment and self‐confidence of students with learning difficulties. An in‐depth discussion focuses on lesson planning for the individual needs and group needs of students by implementation of self‐regulated learning strategies, based on a case study in a special school in Hong Kong. A multiple methods research design was envisaged for the implementation phase of this participatory action research. Lesson observations, video recordings, teachers’ diaries and students’ interviews were collected during one academic year in a form 5 (equal to year 12 in the UK) classroom. It is suggested that curriculum design should include various elements: learning knowledge, values and attitudes, and generic skills. This differentiated curriculum design showed how subject learning targets could be responsive to both the individual and the group needs of students with learning difficulties. Conclusions also indicate that assisting students to become aware of their individual needs is beneficial both for learning and for curriculum design.  相似文献   

Towards a heuristic frame for transferring e-government technology     

Gabriel Marcuzzo do Canto Cavalheiro  Luiz Antonio Joia 《Government Information Quarterly》2014

This article addresses challenges in accomplishing technology transfer process involving the adaptation and implementation of e-government applications from a donor country to a recipient country. Here it is claimed that prior e-government research has overlooked existing technology transfer literature from the field of knowledge management. This work is aimed at addressing the underlying issues associated with the transfer of e-government technology, given different characteristics of donor and recipient organizations in terms of the socio-economic context and the dynamics of the technological infrastructure. Based on a review, interpretation, and synthesis of a broad range of both technology transfer, e-government and knowledge management literature, we extend the Information Technology Transfer Life-Cycle Model, as this well-known model was derived entirely based on empirical evidence. To this end, we propose a heuristic frame for e-government technology transfer. Finally, five propositions accrued from both the literature review and the proposed heuristic frame are set forth to be further tested, in order to better understand the process dynamics of e-government technology transfer between countries.  相似文献   

Applying the technology acceptance model to a Spanish City Hall     

José Luis Moreno Cegarra  Juan Gabriel Cegarra Navarro  José Rodrigo Córdoba Pachón 《International Journal of Information Management》2014

This paper examines the relative importance and significance of the four technology enablers introduced by Davis (1989) in the technology acceptance model (TAM) (perceived ease of use, perceived usefulness, attitude towards using and behavioural intention) for use on four different levels of citizen engagement in e-government (null, publish, interact and transact). An extended technology acceptance model (TAM) is developed to test citizen engagement towards online e-government services from a sample of 307 citizens who used the benefits advisor tool within a Spanish City Hall. Although the proposed model follows TAM and explains the intention towards the actual use of e-government by postulating four direct determinants, “A, PU, PEOU and BI” have been considered as parallel processes, meaning that each can have separate influence in different levels of citizen engagement. To achieve this goal, a multinomial logistic regression is developed and tested to confirm the explanatory power of the four technology enablers on the four different levels of e-government. Our findings further suggest that in order to implement e-government, some of the enablers matter more than others to move from one level of citizen engagement to another. The main contribution of the paper is to question the use of existing models which seek to represent the relationship between technology enablers and the adoption of e-government services without considering their impacts on citizens’ engagement. The implications of the findings are discussed and useful insights are provided in relation to policy recommendations geared to create appropriate conditions to build citizens’ engagement intent of use of e-government services.  相似文献   

Contamination of lithium heparin blood by K2-ethylenediaminetetraacetic acid (EDTA): an experimental evaluation     

Gabriel Lima-Oliveira  Gian Luca Salvagno  Elisa Danese  Giorgio Brocco  Gian Cesare Guidi  Giuseppe Lippi 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2014,24(3):359-367

Introduction:

The contamination of serum or lithium heparin blood with ethylenediaminetetraacetic acid (EDTA) salts may affect accuracy of some critical analytes and jeopardize patient safety. The aim of this study was to evaluate the effect of lithium heparin sample contamination with different amounts of K₂EDTA.

Materials and methods:

Fifteen volunteers were enrolled among the laboratory staff. Two lithium heparin tubes and one K₂EDTA tube were collected from each subject. The lithium-heparin tubes of each subject were pooled and divided in 5 aliquots. The whole blood of K₂EDTA tube was then added in scalar amount to autologous heparinised aliquots, to obtained different degrees of K₂EDTA blood volume contamination (0%; 5%; 13%; 29%; 43%). The following clinical chemistry parameters were then measured in centrifuged aliquots: alanine aminotranspherase (ALT), bilirubin (total), calcium, chloride, creatinine, iron, lactate dehydrogenase (LD), lipase, magnesium, phosphate, potassium, sodium.

Results:

A significant variation starting from 5% K₂EDTA contamination was observed for calcium, chloride, iron, LD, magnesium (all decreased) and potassium (increased). The variation of phosphate and sodium (both increased) was significant after 13% and 29% K₂EDTA contamination, respectively. The values of ALT, bilirubin, creatinine and lipase remained unchanged up to 43% K₂EDTA contamination. When variations were compared with desirable quality specifications, the bias was significant for calcium, chloride, LD, magnesium and potassium (from 5% K₂EDTA contamination), sodium, phosphate and iron (from 29% K₂EDTA contamination).

Conclusions:

The concentration of calcium, magnesium, potassium, chloride and LD appears to be dramatically biased by even modest K₂EDTA contamination (i.e., 5%). The values of iron, phosphate, and sodium are still reliable up to 29% K₂EDTA contamination, whereas ALT, bilirubin, creatinine and lipase appear overall less vulnerable towards K₂EDTA contamination.  相似文献   

Balancing technology and physician-patient knowledge through an unlearning context     

Juan-Gabriel Cegarra-NavarroAuthor Vitae  Gabriel Cepeda-Carrion^{Author Vitae} 《International Journal of Information Management》2011,31(5):420-427

The Spanish health care system has undergone important changes with regard to the development of new homecare services known as “Hospital in the Home”. This paper investigates the approaches that hospital in the home units (HHUs) have used to update physician/patient knowledge and the technology knowledge of their members and relates them to an unlearning context and improvement in the quality of health services. These relationships are examined through an empirical investigation of 55 doctors and 62 nurses belonging to 44 HHUs. The research findings suggest that the key benefits of an unlearning context in HHUs are clear: it enables them to identify and replace poor practices and also avoids the reinvention of the wheel; it enables cost reduction by minimizing unnecessary work caused by the use of poor methods; and it enables improvements in services to patients.  相似文献   

Effects of motion control footwear on running: a systematic review     

Cheung RT  Wong MY  Ng GY 《Journal of sports sciences》2011,29(12):1311-1319

Excessive foot pronation is a risk factor of running injuries and motion control footwear is designed to control foot pronation. With the movement transfer between foot pronation and tibial rotation, motion control footwear may not only be confined to controlling foot pronation. In view of the controversies in the literature on effectiveness of motion control footwear, this paper reviewed the efficacy of motion control footwear functions as reported in the literature. Eligible studies were identified from seven electronic databases. Two independent authors extracted the data and assessed the methodological qualities using the Jadad Scale. A total of 14 quasi randomised controlled trials were included. Even though the included studies were rated as "low quality" according to the Jadad Scale, the data were pooled and analysed. Results revealed that motion control footwear was effective in reducing the amount of foot pronation and the peak vertical impact during landing. There is no evidence that suggests motion control footwear for controlling kinematics of the proximal segments.  相似文献   

Avoidance to wipe alcohol before venipuncture is not a source of spurious hemolysis     

Gian Luca Salvagno  Elisa Danese  Gabriel Lima-Oliveira  Gian Cesare Guidi  Giuseppe Lippi 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2013,23(2):201-205

Background

It is still uncertain whether or not avoidance to let disinfectant alcohol dry at the site of venipuncture is a source of spurious hemolysis when drawing venous blood.

Methods:

In a consecutive series of 52 outpatients referred for routine laboratory testing, venous blood was drawn by direct venipuncture with (odd group) or without (pair group) wiping 70% isopropyl alcohol at the site of venipuncture. A 3.5 mL evacuated tube with clot activator and gel separator was drawn from a vein of the upper limb, serum was immediately separated with standard centrifugation and tested for potassium, lactate dehydrogenase (LD), aspartate aminotransferase (AST) and hemolysis index (HI) on Roche Cobas.

Results:

No specimen was discarded for unsatisfactory venipuncture. No differences for age and gender were observed between groups. As regards the four parameters investigated, no significant differences could be observed between patients in whom blood was drawn with or without letting the alcohol dry. It is also noteworthy that no sample in both groups exceeded the conventional sample rejection threshold of cell-free hemoglobin.

Conclusions:

The results of our prospective, randomized study attest that failure to wipe alcohol at the site of venipuncture should not be considered as a potential source of spurious hemolysis when drawing blood.  相似文献   

Incorrect order of draw could be mitigate the patient safety: a phlebotomy management case report     

Gabriel Lima-Oliveira  Giuseppe Lippi  Gian Luca Salvagno  Martina Montagnana  Geraldo Picheth  Gian Cesare Guidi 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2013,23(2):218-223

Procedures involving phlebotomy are critical for obtaining diagnostic blood specimens and represent a well known and recognized problem, probably among the most important issues in laboratory medicine. The aim of this report is to show spurious hyperkalemia and hypocalcemia due to inadequate phlebotomy procedure. The diagnostic blood specimens were collected from a male outpatient 45 years old, with no clinical complaints. The tubes drawing order were as follows: i) clot activator and gel separator (serum vacuum tube), ii) K₃EDTA, iii) a needleless blood gas dedicated-syringe with 80 I.U. lithium heparin, directly connected to the vacuum tube holder system. The laboratory testing results from serum vacuum tube and dedicated syringe were 4.8 and 8.5 mmol/L for potassium, 2.36 and 1.48 mmol/L for total calcium, respectively. Moreover 0.15 mmol/L of free calcium was observed in dedicated syringe. A new blood collection was performed without K₃EDTA tube. Different results were found for potassium (4.7 and 4.5 mmol/L) and total calcium (2.37 and 2.38 mmol/L) from serum vacuum tube and dedicated syringe, respectively. Also free calcium showed different concentration (1.21 mmol/L) in this new sample when compared with the first blood specimen. Based on this case we do not encourage the laboratory managers training the phlebotomists to insert the dedicated syringes in needle-holder system at the end of all vacuum tubes. To avoid double vein puncture the dedicated syringe for free calcium determination should be inserted immediately after serum tubes before EDTA vacuum tubes.  相似文献   

IS THERE A TWO-STEP FLOW OF AGENDA-SETTING?     

Weimann  Gabriel; Brosius  Hans-Bernd 《Int. Journal of Public Opinion Research》1994,6(4):323-341

The present study integrates two concepts: the notion of opinionleadership, as conceptualized and measured by the Strength ofPersonality (SP) scale, and the agenda-setting process. Thus,we suggest and test a two-step flow model in which certain individuals,the influentials, identify emerging issues in the mass mediaand then diffuse these issues to others via their personal networks.Based on a series of six national surveys conducted in Germany(1990) measuring issue salience and various personal characteristics,this study highlights the role certain individuals play in theemergence of the public agenda. The degree to which individualscan be influenced, measured by the SP scale, is found to bea powerful predictor of the formation of personal agendas, withhigh SP individuals differing from others in their identificationof emerging public issues. However, the analysis reveals thecomplexity of these relationships: they depend on the obtrusivenessof the issue, and they vary over time and location (East orWest Germany). The findings encourage the empirical pursuitof the suggested ‘two-step flow model’ as appliedto the agenda-setting process.  相似文献