Isomotive dielectrophoresis for enhanced analyses of cell subpopulations.

As the relentless dream of creating a true lab-on-a-chip device is closer to realization than ever before, which will be enabled through efficient and reliable sample characterization systems. Dielectrophoresis (DEP) is a term used to describe the motion of dielectric particles/ cells, by means of a non-uniform electric field (AC or DC). Cells of different dielectric properties (i.e., size, interior properties, and membrane properties) will act differently under the influence of dielectrophoretic force. Therefore, DEP can be used as a powerful, robust, and flexible tool for cellular manipulation, separation, characterization, and patterning. However, most recent DEP applications focus on trapping, separation, or sorting particles. The true value of DEP lies in its analytical capabilities which can be achieved by utilizing isomotive dielectrophoresis (isoDEP). In isoDEP, the gradient of the electric field-squared is constant, hence, upon the application of electric field, all particles/cells that share the same dielectric properties will feel the same constant dielectrophoretic force i.e., translate through the micro-channel at the same velocity. However, DEP is not the only acting force upon particles inside an isoDEP device, other electrokinetics, including but not limited to electrothermal hydrodynamics, might act on particles simultaneously. Within this dissertation, electrothermal-based experiments have been conducted to assess the effect of such undesired forces. Also, to maximize the relative DEP force over other forces for a given cell/particle size, design parameters such as microchannel width, height, fabrication materials, lid thickness, and applied electric field must be properly tuned. In this work, scaling law analyses were developed to derive design rules that relate those tunable parameters to achieve the desired dielectrophoretic force for cell analysis. Initial results indicated that for a particle suspended in 10 mS/m media, if the channel width and height are below 10 particle diameters, the electrothermal-driven flow is reduced by ∼ 500 times compared to the 500 µm thick conventional isoDEP device. Also, Replacing glass with silicon as the device’s base for an insulative-based isoDEP, reduces the electrothermal induced flow by ∼ 20 times. Within this dissertation, different device designs and fabrication methods were attempted in order to achieve an isoDEP platform that can characterize and differentiate between live and dead phytoplankton cells suspended in the same solution. Unfortunately, unwanted electrokinetics (predicted by the previously mentioned scaling law analysis) prevented comprehensive isoDEP analysis of phytoplankton cells. Due to isoDEP device limitations and other complications, other techniques were pursued to electrically characterize phytoplankton cells in suspension. An electrochemical-based platform utilizing impedance spectroscopy measurements was used to extract the electrical properties of phytoplankton cells in suspension. Impedance spectroscopy spectra were acquired, and the single-shell model was applied to extract the specific membrane capacitance, cytoplasm permittivity, and conductivity of assumingly spherical cells in suspension utilizing Maxwell’s mixture theory of a controlled volume fraction of cells. The impedance of suspensions of algae were measured at different frequencies ranging from 3 kHz to 10 MHz and impedance values were compared to investigate differences between two types of cells by characterizing their change in cytoplasm permittivity and membrane capacitance. Differentiation between healthy control and nitrogen-depleted cultured algae was attempted. The extracted specific membrane capacitances of Chlamydomonas and Selenastrum were 15:57 ± 3:62 and 40:64 ± 12:6 mF/m2 respectively. Successful differentiation based on the specific membrane capacitance of different algae species was achieved. However, no significant difference was noticed between nitrogen abundant and nitrogen depleted cultures. To investigate the potential of isoDEP for cell analysis, a comparison to existing dielectrophoresis-based electrokinetic techniques was encouraged, including electrorotation (ROT) microfluidic platforms. The ROT microfluidic chip was used to characterize M17, HEK293, T-lymphocytes, and Hela single cells. Through hands-on experience with ROT, the advantages and disadvantages of this approach and isoDEP are apparent. IsoDEP proves to be a good characterization tool for subpopulation cell analysis with potential higher throughput compared to ROT while maintaining simple fabrication and operation processes. To emphasize the role of dielectrophoresis in biology, further studies utilizing the 3DEP analytical system were used to determine the electrical properties of Drosophila melanogaster (Kc167) cells ectopically expressing Late embryogenesis abundant (LEA) proteins from the anhydrobiotic brine shrimp, Artemia franciscana. Dielectrophoretic-based characterization data demonstrates that single expression of two different LEA proteins, AfrLEA3m and AfrLEA6, both increase cytoplasmic conductivity of Kc167 cells to a similar extend above control values. The extracted DEP data supported previously reported data suggesting that AfrLEA3m can interact directly with membranes during water stress. This hypothesis was strengthened using scanning electron microscopy, where cells expressing AfrLEA3m were found to retain their spherical morphology during desiccation, while control cells exhibited a larger variety of shapes in the desiccated state

最適オフセット平均化処理 : 反射記録のS/N比向上のための新解析手法と上町断層への適用

博士(理学)大阪市立大

Design and evaluation of an energy storage system for helicopters

This paper presents the design and evaluation of an energy storage system (ESS) for helicopters with the aim to recover the kinetic energy in the rotor available after landing and to be able to control the 270V dc bus voltage during load disturbances. A study is conducted in order to identify the suitable mix of commercially available energy storage devices with the aim of obtaining the minimum weight, exploring also the possibility to implement a hybrid supercapacitor-battery system. On the converter side, commercially available Silicon and Silicon-Carbide devices have been evaluated to achieve also the smallest size/weight

Garhy-Generated Family of Distributions with Application

This paper introduces a new family of continuous distributions called a Garhy generated family of distributions. Some mathematical properties of this family are discussed. The derived properties are hold to any proper distribution in this family. Some special sub-models in the new family are derived. General explicit expressions for the quantile function, ordinary and incomplete moments, generating function and order statistics are obtained. The estimation of the model parameters is discussed by using maximum likelihood and the potentiality of the extended family is illustrated with one application to real data. Keywords: Kumaraswamy distribution; Exponetiated distribution; Moments; quantile function, Maximum likelihood estimation

Safety Profile and Patient Satisfaction in an Egyptian Cardiac Critical Care Unit

Background: Patient safety was one of the most important issues that arisen in health care management many studies were done at different cities to evaluate healthcare safety goals, the development of a checklist might help in improving the safety culture Purpose: Our work aimed to Measure the patient satisfaction at CCU, and assess the patient safety culture at CCU and finally develop Patient safety Checklist to improve performance Method: Our study was carried out in an adult Cardiac Critical care unit (CCU) at Tanta University hospital using the following Tools Safety Culture Survey Assessment toolDesigned safety checklistPatient Satisfaction Questionnaire (PSQ) It included the following phases Assessment of the safety cultureDevelopment of the checklistEvaluation of the checklist Results Study results claim that safety culture are poor in CCU especially for involvement of staff in decision making, and the absent of Safety rules and procedure which not supported from top management. But the new established safety checklist arise the safety awareness among the CCU staff. Most of patients complaining of waiting time, insurance coverage, care services, availability resources and perfection. Furthermore many physicians skills need more training to “be careful with patient’s complain, Explaining the diagnosis and treatment strategies with patients, be good listener’s, and Explain the medical terms”. Finally, patients feel insecure for all medical problems. Keywords: Safety goals- cardiac critical care- patient satisfaction-checklist DOI: 10.7176/JHMN/62-07 Publication date:May 31st 201

A FRAMEWORK FOR THE EVALUATION OF CYBERSECURITY EFFECTIVENESS OF ABU DHABI GOVERNMENT ENTITIES

Cyberspace has become one of the new frontiers for countries to demonstrate their power to survive in the digitized world. The UAE has become a major target for cyber conflicts due to the rapid increase in economic activity and technology. Further, the widespread use of the internet in the region to the tune of 88% by the end of 2014 has exposed the critical infrastructure to all forms of cyber threats. In this dissertation, the researcher presents a detailed study of the existing cybersecurity defences globally and an investigation into the factors that influence the effectiveness of cybersecurity defences in Abu Dhabi government entities. Further, the role of cybersecurity education, training, and awareness in enhancing the effectiveness of cybersecurity and the role of senior management in providing strategic direction to government entities on cybersecurity are evaluated in addition to determining the contribution of strategic planning and technology level in ensuring an effective cybersecurity system. The study has evaluated the level of Cybersecurity Effectiveness (CSE) in Abu Dhabi Government Entities and the results show that Science and Technology entity performed better than all other Entities with CSE Mean = 4.37 while Public Order showed the least performance with CSE Mean = 3.83 and the combined model of six factors with R-square value 0.317 after multiple regression implying that 32% change in CSE in the government entities is occurring due to the six (6) independent variables used in the study. Further, results show that management has the responsibility of putting in place strategies, frameworks and policies that respond appropriately to the prevention, detection and mitigation of cyberattacks. Results further indicate that culture-sensitive training and awareness programmes add to the quality and effectiveness of cybersecurity systems in government entities. Further, study findings reveal that qualified and experienced personnel in government entities show a greater understanding of cyber and information security issues. Finally, the researcher proposes a cybersecurity framework and a checklist, with checkpoints, for evaluating the effectiveness of cybersecurity systems within government entities and future research interventions

Geochemical and Radiological Baseline Studies and Environmental Impact of the Area Surrounding Barakah Nuclear Power Plant, UAE

Geochemical, mineralogical and natural radiation analysis techniques were used for establishment of geochemical and radiological baseline around Barakah Nuclear Power Plant, UAE. The natural radioactivity concentrations of 238U (226Ra), 232Th and 40K were measured for soil, shore and bottom sediment samples, using gamma spectrometry equipped with HPGe detector. In addition, alpha spectrometry was used to measure 234U/238U ratio for some selected samples. Furthermore, inductively coupled plasma atomic emission spectroscopy was used to measure the concentrations of heavy metals and Rare Earth Elements (REE). The grain size of the samples ranged from fine to coarse sand. The inverse relationship between grain size and heavy metal contaminations was validated. The results indicated the mean concentrations of heavy metals and REE are much higher in soil samples compared to bottom sediments, which in turn relatively higher than shore samples. All heavy metals concentrations were significantly below the UAE soil contamination safe limits. The levels of heavy metals and REE reported in the UAE were lower than the levels reported in the soil, shore and bottom sediments of several countries around the world. Enrichment factor calculated for heavy metals shows no to moderate enrichment (As and Cd), while the contamination factor (CF) was CF\u3c1 which indicates low contamination factor. Geoaccumulation results suggest uncontaminated area. Furthermore, the pollution load index, \u3e1, indicates no pollution in the area. With exception of La in shore samples, all the REE show no enrichment. Contamination factor for REE indicates a low contamination factor and geoaccumulation results indicate that the studied area was uncontaminated. Moreover, the pollution load index indicates no pollution in the area. The measured gamma activity concentrations in shore-sediment samples are much lower comparing to those concentrations in soil and bottom sediments. The average activity concentrations of 238U (226Ra) are 15.68±0.56, 4.43±0.39 and 4.73±0.47 Bq/kg, for 232Th are 8.3±0.23, 1.68±0.17 and 1.83±0.24 Bq/kg and for 40K, are 349.72±11.76, 106.3±7.27 and 105.23±10.03 Bq/kg in soil, shore and bottom sediment samples, respectively. Anthropogenic radionuclide 137Cs is low than the detection limit in the studied area. The 234U/238U activity ratios show wide range from 0.59 to 2.24 indicating effects of sources and in situ processes. In addition, the hazard parameters such as Radium equivalent and absorption dose were estimated and all are below the world average. The spatial distribution for heavy metals, REE and natural radionuclides was generally more compact in the south compared to the north, with less severe contamination in the east and west. Relationships between heavy metals, REE and natural radioactivity concentrations were investigated and varied between soil, shore and bottom sediment samples. The previous relationships may indicate that uranium and thorium have detrital sources possibly associated with silicate minerals

Synthesis of polysulfone/polyamide thin film nanocomposite membranes for forward osmosis applications

Forward osmosis (FO) has attracted significant interest as a promising alternative to reverse osmosis (RO) in membrane-based water desalination applications. FO water flux, salt rejection and reverse solute flux are three critical parameters affecting membrane performance. Thin film composite (TFC) membranes have been widely used in FO processes. A typical TFC membrane consists of a rejection polyamide (PA) layer on top of a highly porous support layer. In the current study, carboxyl functionalized multi-walled carbon nanotubes (F-MWCNTs) were used as nano-fillers in the membrane rejection layer to enhance the FO membrane performance. Polyamide (PA) thin film nano-composite (TFNC) membranes were synthesized on top of polysulfone (PSF) porous support layers by interfacial polymerization (IP) using m-phenylenediamine (MPD) in water and trimesoyl chloride (TMC) in hexane. The PSF support layer was synthesized by phase inversion in a water bath of a casting solution of PSF and polvinylpyrrolidone (PVP) (pore forming agent) dissolved in anhydrous dimethyl formamide (DMF). Multi-walled carbon nanotubes were functionalized by oxidation in strong acidic solutions, and then incorporated in the MPD aqueous solution during IP. For the support layer, PSF and PVP concentrations were varied while monomers (MPD, TMC) concentrations, contact time and curing temperature were varied for the rejection layer. Experimental designs for both the support and the rejection layers were carried out using Design-Expert software including statistical analysis to identify the most significant factors affecting the membrane performance. The support layer of 18 wt% PSF and 2 wt% PVP was selected as the membrane support with the highest possible FO water flux and minimum reverse solute flux while the PA rejection layer of 4 wt/vol% MPD and 0.2 wt/vol% TMC was selected as the membrane rejection layer with a salt rejection of 88.30±0.11%. Finally, the amount of F-MWCNTs was varied from 0.01 to 0.2 wt/vol% to study their effect on the membrane morphology and performance. The synthesized membranes were characterized using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectrophotometry (FTIR) and Brunauer-Emmett-Teller gas adsoprtion analysis (BET). FO performance was investigated using deionized water as the feed solution and 2 M NaCl as the draw solution. It was found that F-MWCNTs enhanced the membrane hydrophilicity and surface roughness that led to increased FO water flux. Most importantly, the salt rejection was also increased at low concentrations of F-MWCNTs (\u3c 0.05 wt/vol%). The membrane with 0.01 wt/vol% F-MWCNTs showed the highest salt rejection (90.05±0.25%) with a FO water flux of 50.23±0.93 L/m2 h and a reverse solute flux of 2.76±0.21 g/m2h, thus outperforming thin film composite FO membranes reported in literature