3D Energy Harvester Evaluation

This paper discusses the characterization and evaluation of an MEMS based electrostatic generator, a part of the power supply unit of the self-powered microsystem[1,2,3]. The designed generator is based on electrostatic converter and uses the principle of conversion of non-electric energy into electrical energy by periodical modification of gap between electrodes of a capacitor [4]. The structure is designed and modeled as three-dimensional silicon based MEMS. Innovative approach involving the achievement of very low resonant frequency of the structure (about 100Hz) by usage of modified long cantilever spring design, minimum area of the chip, 3D work mode, the ability to be tuned to reach desired parameters, proves promising directions of possible further development

Design and Fabrication of 3D Electrostatic Energy Harvester

This paper discusses the design of an electrostatic generator, power supply component of the self-powered microsystem, which is able to provide enough energy to power smart sensor chains or if necessary also other electronic monitoring devices. One of the requirements for this analyzer is the mobility, so designing the power supply expects use of an alternative way of getting electricity to power the device, rather than rely on periodic supply of external energy in the form of charging batteries, etc. In this case the most suitable method to use is so-called energy harvesting – a way how to gather energy. This uses the principle of non-electric conversion of energy into electrical energy in the form of converters. The present study describes the topology design of such structures of electrostatic generator. Structure is designed and modeled as a three-dimensional silicon based MEMS. Innovative approach involving the achievement of very low resonant frequency of the structure, while the minimum area of the chip, the ability to work in all 3 axes of coordinate system and ability to be tuned to reach desired parameters proves promising directions of possible further development of this issue. The work includes simulation of electro-mechanical and electrical properties of the structure, description of its behavior in different operating modes and phases of activity. Simulation results were compared with measured values of the produced prototype chip. These results can suggest possible modifications to the proposed structure for further optimization and application environment adaptation

A Risk-Based Approach for Examining Vertical Separation Distances in On-Site Wastewater Treatment Sytems

Regulations regarding the use of on-site wastewater treatment systems in many states lack a sufficient scientific basis, which in many cases restricts the use of on-site systems, drives up cost, and restricts innovation of new treatment technologies. Of particular regulatory concern is the minimum vertical separation distance (VSD) located in the area between the trench bottom of the subsurface soil absorption system and any restricting or limiting layer. The minimum VSD needed for proper effluent treatment is based on many complex and interrelated factors regarding physical, chemical, and biological soil conditions at a particular site. Research has shown that depending on soil type and conditions, VSD between 1.5 feet and 4 feet is enough to adequately treat effluent yet many states use a one size fits all approach when setting regulations for on-site treatment systems. A stochastic mathematical model has been developed that provides an estimation of the probability that a contaminant concentration will reach a certain point below the trench bottom of the subsurface soil absorption system. This model has been incorporated into a simple, easy-to-use, Excel® based computer program that allows the user to evaluate the potential range of fecal coliform concentrations that may reach a specified groundwater or surface water location. This model has been developed to aid regulators, land use planners, and designers to quickly evaluate the associated risks of contamination from a specified on-site wastewater treatment system in a specified soi

A Risk-Based Approach for Examining Vertical Separation Distances in On-Site Wastewater Treatment Sytems

Regulations regarding the use of on-site wastewater treatment systems in many states lack a sufficient scientific basis, which in many cases restricts the use of on-site systems, drives up cost, and restricts innovation of new treatment technologies. Of particular regulatory concern is the minimum vertical separation distance (VSD) located in the area between the trench bottom of the subsurface soil absorption system and any restricting or limiting layer. The minimum VSD needed for proper effluent treatment is based on many complex and interrelated factors regarding physical, chemical, and biological soil conditions at a particular site. Research has shown that depending on soil type and conditions, VSD between 1.5 feet and 4 feet is enough to adequately treat effluent yet many states use a one size fits all approach when setting regulations for on-site treatment systems. A stochastic mathematical model has been developed that provides an estimation of the probability that a contaminant concentration will reach a certain point below the trench bottom of the subsurface soil absorption system. This model has been incorporated into a simple, easy-to-use, Excel® based computer program that allows the user to evaluate the potential range of fecal coliform concentrations that may reach a specified groundwater or surface water location. This model has been developed to aid regulators, land use planners, and designers to quickly evaluate the associated risks of contamination from a specified on-site wastewater treatment system in a specified soi

High Power Solid State Retrofit Lamp Thermal Characterization and Modeling

Thermal and thermo-mechanical modeling and characterization of solid state lightening (SSL) retrofit LED lamp are presented in this paper. Paramount importance is to design SSL lamps for reliability, in which thermal and thermo-mechanical aspects are key points. The main goal is to get a precise 3D thermal lamp model for further thermal optimization. Simulations are performed with ANSYS and CoventorWare software tools to compere different simulation approaches. Simulated thermal distribution has been validated with thermal measurement on a commercial 8W LED lamp. Materials parametric study has been carried out to discover problematic parts for heat transfer from power LEDs to ambient and future solutions are proposed. The objectives are to predict the thermal management by simulation of LED lamp, get more understanding in the effect of lamp shape and used materials in order to design more effective LED lamps and predict light quality, life time and reliability

RyR1-targeted drug discovery pipeline integrating FRET-based high-throughput screening and human myofiber dynamic Ca2+ assays.

Elevated cytoplasmic [Ca2+] is characteristic in severe skeletal and cardiac myopathies, diabetes, and neurodegeneration, and partly results from increased Ca2+ leak from sarcoplasmic reticulum stores via dysregulated ryanodine receptor (RyR) channels. Consequently, RyR is recognized as a high-value target for drug discovery to treat such pathologies. Using a FRET-based high-throughput screening assay that we previously reported, we identified small-molecule compounds that modulate the skeletal muscle channel isoform (RyR1) interaction with calmodulin and FK506 binding protein 12.6. Two such compounds, chloroxine and myricetin, increase FRET and inhibit [3H]ryanodine binding to RyR1 at nanomolar Ca2+. Both compounds also decrease RyR1 Ca2+ leak in human skinned skeletal muscle fibers. Furthermore, we identified compound concentrations that reduced leak by > 50% but only slightly affected Ca2+ release in excitation-contraction coupling, which is essential for normal muscle contraction. This report demonstrates a pipeline that effectively filters small-molecule RyR1 modulators towards clinical relevance

Local recovery of cardiac calcium‐induced calcium release interrogated by ultra‐effective, two‐photon uncaging of calcium

KEY POINTS: In cardiac myocytes, subcellular local calcium release signals, calcium sparks, are recruited to form each cellular calcium transient and activate the contractile machinery. Abnormal timing of recovery of sparks after their termination may contribute to arrhythmias. We developed a method to interrogate recovery of calcium spark trigger probabilities and their amplitude over time using two‐photon photolysis of a new ultra‐effective caged calcium compound. The findings confirm the utility of the technique to define an elevated sensitivity of the calcium release mechanism in situ and to follow hastened recovery of spark trigger probabilities in a mouse model of an inherited cardiac arrhythmia, which was used for validation. Analogous methods are likely to be applicable to investigate other microscopic subcellular signalling systems in a variety of cell types. ABSTRACT: In cardiac myocytes Ca(2+)‐induced Ca(2+) release (CICR) from the sarcoplasmic reticulum (SR) through ryanodine receptors (RyRs) governs activation of contraction. Ca(2+) release occurs via subcellular Ca(2+) signalling events, Ca(2+) sparks. Local recovery of Ca(2+) release depends on both SR refilling and restoration of Ca(2+) sensitivity of the RyRs. We used two‐photon (2P) photolysis of the ultra‐effective caged Ca(2+) compound BIST‐2EGTA and laser‐scanning confocal Ca(2+) imaging to probe refractoriness of local Ca(2+) release in control conditions and in the presence of cAMP or low‐dose caffeine (to stimulate CICR) or cyclopiazonic acid (CPA; to slow SR refilling). Permeabilized cardiomyocytes were loaded with BIST‐2EGTA and rhod‐2. Pairs of short 2P photolytic pulses (1 ms, 810 nm) were applied with different intervals to test Ca(2+) release amplitude recovery and trigger probability for the second spark in a pair. Photolytic and biological events were distinguished by classification with a self‐learning support vector machine (SVM) algorithm. In permeabilized myocytes data recorded in the presence of CPA showed a lower probability of triggering a second spark compared to control or cAMP conditions. Cardiomyocytes from a mouse model harbouring the arrhythmogenic RyR(R420Q) mutation were used for further validation and revealed a higher Ca(2+) sensitivity of CICR. This new 2P approach provides composite information of Ca(2+) release amplitude and trigger probability recovery reflecting both SR refilling and restoration of CICR and RyR Ca(2+) sensitivity. It can be used to measure the kinetics of local CICR recovery, alterations of which may be related to premature heart beats and arrhythmias

Culture of equine fibroblast-like synoviocytes on synthetic tissue scaffolds towards meniscal tissue engineering: a preliminary cell-seeding study

Introduction. Tissue engineering is a new methodology for addressing meniscal injury or loss. Synovium may be an ideal source of cells for in vitro meniscal fibrocartilage formation, however, favorable in vitro culture conditions for synovium must be established in order to achieve this goal. The objective of this study was to determine cellularity, cell distribution, and extracellular matrix (ECM) formation of equine fibroblast-like synoviocytes (FLS) cultured on synthetic scaffolds, for potential application in synovium-based meniscal tissue engineering. Scaffolds included open-cell poly-L-lactic acid (OPLA) sponges and polyglycolic acid (PGA) scaffolds cultured in static and dynamic culture conditions, and PGA scaffolds coated in poly-L-lactic (PLLA) in dynamic culture conditions.Materials and Methods. Equine FLS were seeded on OPLA and PGA scaffolds, and cultured in a static environment or in a rotating bioreactor for 12 days. Equine FLS were also seeded on PGA scaffolds coated in 2% or 4% PLLA and cultured in a rotating bioreactor for 14 and 21 days. Three scaffolds from each group were fixed, sectioned and stained with Masson’s Trichrome, Safranin-O, and Hematoxylin and Eosin, and cell numbers and distribution were analyzed using computer image analysis. Three PGA and OPLA scaffolds from each culture condition were also analyzed for extracellular matrix (ECM) production via dimethylmethylene blue (sulfated glycosaminoglycan) assay and hydroxyproline (collagen) assay. PLLA coated PGA scaffolds were analyzed using double stranded DNA quantification as areflection of cellularity and confocal laser microscopy in a fluorescent cell viability assay.Results. The highest cellularity occurred in PGA constructs cultured in a rotating bioreactor, which also had a mean sulfated glycosaminoglycan content of 22.3 µg per scaffold. PGA constructs cultured in static conditions had the lowest cellularity. Cells had difficulty adhering to OPLA and the PLLA coating of PGA scaffolds; cellularity was inversely proportional to the concentration of PLLA used. PLLA coating did not prevent dissolution of the PGA scaffolds. All cell scaffold types and culture conditions produced non-uniform cellular distribution.Discussion/Conclusion. FLS-seeding of PGA scaffolds cultured in a rotating bioreactor resulted in the most optimal cell and matrix characteristics seen in this study. Cells grew only in the pores of the OPLA sponge, and could not adhere to the PLLA coating of PGA scaffold, due to the hydrophobic property of PLA. While PGA culture in a bioreactor produced measureable GAG, no culture technique produced visible collagen. For this reason, and due to the dissolution of PGA scaffolds, the culture conditions and scaffolds described here are not recommended for inducing fibrochondrogenesis in equine FLS for meniscal tissue engineering

Uptake-leak balance of SR Ca2+ determines arrhythmogenic potential of RyR2R420Q+/- cardiomyocytes.

Mutations of the RyR2 are channelopathies that can predispose to life threatening catecholaminergic polymorphic ventricular tachycardias (CPVTs) during exercise or stress. However, the cellular and molecular mechanisms that are causal for the arrhythmias downstream of the β-adrenergic receptor (β-AR) activation are not defined. They may be specific and different for each particular RyR2 mutation. Obvious possibilities are the phosphorylation of the mutated RyR2s or the stimulation of the SR Ca2+ pump (SERCA), which could increase SR Ca2+ loading. Potentially arrhythmogenic Ca2+ signals, such as Ca2+ waves, were recorded and analyzed from WT and RyR2R420Q+/- mouse cardiomyocytes with confocal microscopy after field stimulation at 1 Hz. In RyR2R420Q+/- cardiomyocytes we found a higher occurrence and frequency of Ca2+ waves, particularly upon β-AR stimulation with isoproterenol. This was accompanied by a shorter latency to the first spontaneous wave. Wave velocity from raw traces, as well as amplitude and decay time constant (τ) analyzed in de-skewed traces were comparable in both cell types. To obtain further insight into the role of the SERCA we selectively stimulated SERCA in permeabilized myocytes using Fab fragments of a PLB antibody (2D12). Surprisingly, SERCA stimulation alone resulted in considerably higher wave frequencies than when mimicking β-AR stimulation with cAMP, particularly in RyR2R420Q+/- cardiomyocytes. This may be a consequence of some protective SR Ca2+ unloading resulting from the SR Ca2+ leak via phosphorylated RyR2s in cAMP. Spark-to-spark recovery analysis suggested a remarkably higher Ca2+ release sensitivity in RyR2R420Q+/- cells, both in control and upon β-AR stimulation. Together these findings suggest that the fine balance between SR Ca2+ loading via SERCA and the Ca2+ leak via mutated and phosphorylated RyR2s is an important determinant for the overall cellular arrhythmogenicity prevailing in the RyR2R420Q+/- myocytes

Robot George: interactive continuous learning of visual concepts

The video presents the robot George learning visual concepts in dialogue with a tuto