What is the future of electrical impedance spectroscopy in flow cytometry?     

Furkan Gke  Paolo S. Ravaynia  Mario M. Modena  Andreas Hierlemann 《Biomicrofluidics》2021,15(6)

More than 20 years ago, electrical impedance spectroscopy (EIS) was proposed as a potential characterization method for flow cytometry. As the setup is comparably simple and the method is label-free, EIS has attracted considerable interest from the research community as a potential alternative to standard optical methods, such as fluorescence-activated cell sorting (FACS). However, until today, FACS remains by and large the laboratory standard with highly developed capabilities and broad use in research and clinical settings. Nevertheless, can EIS still provide a complement or alternative to FACS in specific applications? In this Perspective, we will give an overview of the current state of the art of EIS in terms of technologies and capabilities. We will then describe recent advances in EIS-based flow cytometry, compare the performance to that of FACS methods, and discuss potential prospects of EIS in flow cytometry.  相似文献   

Electrical power free, low dead volume, pressure-driven pumping for microfluidic applications     

Moscovici M  Chien WY  Abdelgawad M  Sun Y 《Biomicrofluidics》2010,4(4):46501

This paper presents a simple-to-construct, low dead volume pump capable of generating a wide range of positive and negative pressures for microfluidic applications. The pump generates pressure or vacuum by changing the volume of air confined inside a syringe and is able to generate pressures between -95 and +300 kPa with a resolution as high as 1 Pa. Different from syringe pumps and electrokinetic pumping, which are capable of controlling flow rates only, our pump can be used to generate constant flow rates or constant pressures, which are required for certain applications such as the aspiration of biological cells for biophysical characterization. Compared to syringe pumps, the new pump has almost zero dead volume and does not exhibit pulsatile flows. Additionally, the system does not require electrical power and is cost effective (～$100). To demonstrate the capabilities of the pump, we used it to aspirate osteoblasts (MC3T3-E1 cells) and to determine Young's modulus of the cells, to generate a concentration gradient, and to produce variable-sized droplets in microchannels using hydrodynamic focusing.  相似文献   

Determination of the prevalence of anabolic steroids, stimulants, and selected drugs subject to doping controls among elite sport students using analytical chemistry     

Thevis M  Sauer M  Geyer H  Sigmund G  Mareck U  Schänzer W 《Journal of sports sciences》2008,26(10):1059-1065

Drug abuse by adolescents has been investigated in various surveys that reported correlations between age, gender, and activity. However, none of these studies included chemical analyses to help substantiate the statements of participants. In the present study, the urine specimens of 964 students (439 females, 525 males; mean age 22.1 years, s = 1.7), who applied to study sports sciences at university, were assessed for anabolic steroids, stimulants, and selected drugs prohibited in sports. In total, 11.2% of the urine specimens provided contained drugs covered by doping controls. The most frequently detected compound was the major metabolite of tetrahydrocannabinol (9.8%) followed by various stimulants related to amphetamine and cocaine (1.0%). Indications of anabolic steroid use were found in 0.4% of urine samples but originated from contraceptives containing norethisterone. The present study provided unambiguous data on the status quo of drug (ab)use by adolescents hoping for a career related to elite sport or sports sciences. No use of anabolic steroids was detected. However, evidence for stimulants and tetrahydrocannabinol administration was obtained, although not reported by any participant, which highlights the issue of under-reporting in surveys based solely on questionnaires.  相似文献   

Community cartography in health communication: An asset-based mapping approach in four communities in rural Ecuador     

Benjamin R. Bates  Diana L. Marvel  Claudia Nieto-Sanchez  Mario J. Grijalva 《Journal of International and Intercultural Communication》2019,12(3):228-247

Scholars and practitioners are increasingly turning to maps as tools for promoting health and development communication. These maps are often criticized for privileging the interests of the global North and for authorizing (neo)colonial approaches. The authors offer a case of community mapping incorporating asset-based community development that offers an alternative cartography. Drawing on the maps produced by members of four communities in rural Ecuador, the authors articulate how their maps productively use and challenge assumptions about maps. Following this analysis, the authors offer some implications that community-scale maps have for articulating rhetorical alternatives in health and development communication.  相似文献   

Functional shoulder ratios with high velocities of shoulder internal rotation are most sensitive to determine shoulder rotation torque imbalance: a cross-sectional study with elite handball players and controls     

Marcelo Peduzzi de Castro  Pedro Fonseca  Sara Tribuzi Morais  Márcio Borgonovo-Santos  Eduardo Filipe Cruz Coelho  Daniel Cury Ribeiro 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(1):39-50

The aim of the present study was to determine which approach to calculating shoulder ratios is the most sensitive for determining shoulder torque imbalance in handball players. Twenty-six participants (handball athletes, n = 13; healthy controls, n = 13) performed isokinetic concentric and eccentric shoulder internal rotation (IR) and external rotation (ER) assessment at 60, 180 and 300°/s. We used eight approaches to calculating shoulder ratios: four concentric (i.e. concentric ER torque divided by concentric IR torque), and four functional (i.e. eccentric ER torque divided by concentric IR torque) at the velocities of 60, 180 and 300°/s for both IR and ER, and combining 60°/s of ER and 300°/s of IR. A three factorial ANOVA (factors: shoulder ratios, upper limb sides, and groups) along with Tukey’s post-hoc analysis, and effect sizes were calculated. The findings suggested the functional shoulder ratio combining 60°/s of ER and 300°/s of IR is the most sensitive to detect differences between upper limbs for handball players, and between players and controls for the dominant side. The functional shoulder ratio combining 60°/s of ER with 300°/s of IR seems to present advantages over the other approaches for identifying upper limb asymmetries and differences in shoulder torque balance related to throwing.  相似文献   

Insights into Masolino's wall paintings in Castiglione Olona: Advanced reflectance and fluorescence imaging analysis     

Daniela Comelli  Austin Nevin  Gianluca Valentini  Iacopo Osticioli  Emilio Mario Castellucci  Lucia Toniolo  Davide Gulotta  Rinaldo Cubeddu   《Journal of Cultural Heritage》2011,12(1):11-18

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Exploring the Relationship Between Athletes’ Perceptions of the Motivational Climate to Their Compassion,Self-Compassion,Shame, and Pride in Adult Recreational Sport     

Mario S. Fontana  Mary D. Fry  Emily Cramer 《Measurement in physical education and exercise science》2017,21(2):101-111

The purpose of this study was to examine the relationships between athletes’ perceptions of the motivational climate (caring, task-, and ego-involving) to their levels of compassion, self-compassion, pride, and shame in a recreational sport setting. Athletes (N = 164) in a competitive Wiffle Ball tournament completed a survey. A canonical correlation analysis revealed one significant function indicating that athletes’ perceptions of a caring and task-involving motivational climate were associated with higher levels of authentic pride and lower levels of hubristic pride. Results suggest adult recreational sport participants may benefit from experiencing a positive and supportive team climate.  相似文献   

Well-posedness of linear closed- loop Stackelberg Strategies for singularly perturbed systems     

M.A. Salman  J.B. Cruz 《Journal of The Franklin Institute》1979,308(1):25-37

This paper is concerned with a linear closed-loop Stackelberg strategy for singularly perturbed systems. A procedure to obtain a well-posed formulation of the problem, where both fast and slow modes are available for measurements, is given.  相似文献   

Well-Posedness of Singularly Pertubed Nash Games     

B.F. Gardner  J.B. Cruz 《Journal of The Franklin Institute》1978,306(5):355-374

This paper discusses linear-quadratic infinite-time nonzero-sum closed-loop Nash games for systems with fast and slow modes. It is shown via example that the usual order reduction processes utilizing control ideas of singular perturbation analysis leads to an ill-posed reduced order problem. A modification of the performance indices is presented which leads to a well-posed problem, when the usual order reduction method is used. Finally, a hierarchical reduction procedure is proposed which leads to well-posed fast and slow game problems even when the performance indices are not modified.  相似文献   

Measuring the Transfer of Training     

Brenda J. Cruz 《Performance Improvement Quarterly》1997,10(2):83-97

This study examined the use of self-report to measure training transfer by comparing three training transfer assessment methods. Applying a framework provided by instructional alignment theory, the study tested the hypothesis that if training transfer is measured by assessment methods that vary in their degree of alignment with the post-training learning assessment, the training transfer scores would be higher as the degree of alignment increased. Instructional alignment is the extent to which stimulus conditions match across instructional components: intended outcomes, instructional processes, and assessment. Three training transfer assessments were administered to 40 telecommunications technicians approximately 60 days after they completed a training course. The moan transfer score for the job performance assessment with high alignment was significantly higher than the two self-report assessments of moderate and low alignment with effect size differences of 0.96 (p < .01) and 0.87 (p < .01), respectively. The mean scores for the two self-report assessments did not significantly differ. This study has implications for the extensive use of self-report to assess training transfer in both research and training evaluation programs.  相似文献