Variationally consistent modeling of a sensor-actuator based on shape-morphing from electro-chemical–mechanical interactions

This paper concerns the computational modeling of a class of carbon fiber composites, known as shape-morphing and strain-sensing composites. The actuating and sensing performance of such (smart) materials is achieved by the interplay between electrochemistry and mechanics, in particular the ability of carbon fibers to (de)intercalate Li-ions repeatedly. We focus on the actuation and sensing properties of a beam in conjunction with the appropriate “through-the-thickness” properties. Thus, the electro-chemo-mechanical analysis is essentially two-dimensional, and it is possible to rely heavily on the results in Carlstedt et al. (2020). More specifically, the cross-sectional design is composed of two electrodes, consisting of (partly) lithiated carbon fibers embedded in structural battery electrolyte (SBE), on either side of a separator. As a result, the modeling is hierarchical in the sense that (macroscale) beam action is combined with electro-chemo-mechanical interaction along the beam. The setup is able to work as sensor or actuator depending on the choice of control (and response) variables. Although quite idealized, this design allows for a qualitative investigation. In this paper we demonstrate the capability of the developed framework to simulate both the actuator and sensor modes. As proof of concept, we show that both modes of functionality can be captured using the developed framework. For the actuator mode, the predicted deformation is found to be in close agreement with experimental data. Further, the sensor-mode is found to agree with experimental data available in the literature

Computational modelling of structural batteries accounting for stress-assisted convection in the electrolyte

Structural batteries consist of carbon fibres embedded in a porous structural battery electrolyte (SBE), which is composed of two continuous phases: a solid polymer skeleton and a liquid electrolyte containing Li-salt. In this paper we elaborate on a computational modelling framework to study the electro-chemo-mechanical properties of such structural batteries while accounting for the combined action from migration as well as stress-assisted diffusion and convection in the electrolyte. Further, we consider effects of lithium insertion in the carbon fibres, leading to insertion strains. The focus is placed on how the convective contribution to the mass transport within the SBE affects the general electro-chemo-mechanical properties. The numerical results indicate that the convective contribution has only minor influence on the multifunctional performance when the mechanical loading is caused by constrained deformation of constituents during electro-chemical cycling. However, in the case of externally applied mechanical loading that causes severe deformation of the SBE, or when large current pulses are applied, the convective contribution has noticeable influence on the electro-chemical performance. In addition, it is shown that the porosity of the SBE, which affects the effective stiffness as well as the mobility and permeability, has significant influence on the combined mechanical and electro-chemical performance

Experimental analysis of a window air conditioner with R-22 and zeotropic mixture of R-32/125/134a

This study is the result of the cooperative research and development agreement (CRADA) between Oak Ridge National Laboratory and E.I. Du Pont De Nemours and Company, Inc., (CRADA No. 92-0161) for testing the use of heat exchangers as the evaporator and condenser in an air-conditioning rig. Heat exchangers at typical realistic operating conditions were tested with R-22 and with its potential replacement, a ternary mixture of R-32(30%)/R-125(10%)/R-134a(60%). A test rig was built that provided for operation of the low-temperature exchanger (evaporator) with flooded coils. The test results indicated that the performance of the evaporator heat exchanger using ternary mixture, in terms of cooling capacity, would be around 7.4% less than the performance using R-22. The cooling capacity for both refrigerants improved with flooded evaporator operation by 8.6% for R-22 and by 15% for ternary mixture. Compared with R-22 operation, operation with ternary mixture results in slightly higher compressor discharge pressure, lower compressor discharge temperature, slightly lower compressor power consumption, and a higher compressor high-low pressure ratio. Temperature glide for ternary mixture, for both evaporator and condenser, was clearly evident, but not as pronounced as expected because of the pressure drop (and thus the temperature drop) along the coils. Further improvement of the performance of ternary mixture is possible if the evaporator is arranged in a counter-cross-flow configuration to take advantage of the temperature glide. Current evaporator designs are mostly concurrent-cross-flow, which is more appropriate for single-component refrigerants or azeotropic refrigerant mixtures

Purdue College of Pharmacy Experience with Blood Pressure Screenings at the Indiana State Fair

The objective of this community outreach initiative is to develop and implement a student-led blood pressure screening at the Indiana State Fair in conjunction with the Purdue College of Pharmacy and the Hook’s Drug Store Museum. Under the mentorship of two pharmacy faculty members, third- and fourth-year professional PharmD students and pharmacy fellows hold a nine-hour blood pressure screening at the Indiana State Fair each year. The screening is held at the Hook’s Drug Store Museum and the students and fellows sign-up in teams of 3-4 to host the event. Fair-goers visiting the screening have their blood pressure taken using automated blood pressure devices and the readings are recorded into one of three categories: ≤140 mmHg/≤90 mmHg, \u3e140 mmHg/\u3e90 mmHg, or \u3e150 mmHg/\u3e100 mmHg. All patients receive a card with their blood pressure reading, are counseled on hypertension management and possible health complications, and receive a sticker that reads “I had my blood pressure checked at the Indiana State Fair/Purdue College of Pharmacy.” Students complete a reflection following their involvement. Data from the last five years was analyzed. Over the five years, a total of 838 fairgoers have utilized the opportunity to have their blood pressure checked. In addition, 50 pharmacy students, two fellows, and two faculty members have participated in hosting the screening. There has been growing involvement over the years, with 213 individuals visiting the booth in 2019. There has been a steady increase in the percentage of patients with a blood pressure reading in the lowest category. Participation in the Indiana State Fair has become a tradition for the College of Pharmacy as students enjoy and are grateful for such learning opportunities. This initiative allows students to develop and apply their clinical knowledge and communication skills while improving health and awareness of community members

Prenatal phthalate exposures and anogenital distance in Swedish boys

BACKGROUND: Phthalates are used as plasticizers in soft polyvinyl chloride (PVC) and in a large number of consumer products. Because of reported health risks, diisononyl phthalate (DiNP) has been introduced as a replacement for di(2-ethylhexyl) phthalate (DEHP) in soft PVC. This raises concerns because animal data suggest that DiNP may have antiandrogenic properties similar to those of DEHP. The anogenital distance (AGD)-the distance from the anus to the genitals-has been used to assess reproductive toxicity. OBJECTIVE: The objective of this study was to examine the associations between prenatal phthalate exposure and AGD in Swedish infants. METHODS: AGD was measured in 196 boys at 21 months of age, and first-trimester urine was analyzed for 10 phthalate metabolites of DEP (diethyl phthalate), DBP (dibutyl phthalate), DEHP, BBzP (benzylbutyl phthalate), as well as DiNP and creatinine. Data on covariates were collected by questionnaires. RESULTS: The most significant associations were found between the shorter of two AGD measures (anoscrotal distance; AGDas) and DiNP metabolites and strongest for oh-MMeOP [mono(4-methyl-7-hydroxyloctyl) phthalate] and oxo-MMeOP [mono-(2-ethyl-5-oxohexyl) phthalate]. However, the AGDas reduction was small (4%) in relation to more than an interquartile range increase in DiNP exposure. CONCLUSIONS: These findings call into question the safety of substituting DiNP for DEHP in soft PVC, particularly because a shorter male AGD has been shown to relate to male genital birth defects in children and impaired reproductive function in adult males and the fact that human levels of DiNP are increasing globally

Evaluation of a national universal coverage campaign of long-lasting insecticidal nets in a rural district in north-west Tanzania.

\ud \ud Insecticide-treated nets (ITN) are one of the most effective measures for preventing malaria. Mass distribution campaigns are being used to rapidly increase net coverage in at-risk populations. This study had two purposes: to evaluate the impact of a universal coverage campaign (UCC) of long-lasting insecticidal nets (LLINs) on LLIN ownership and usage, and to identify factors that may be associated with inadequate coverage. In 2011 two cross-sectional household surveys were conducted in 50 clusters in Muleba district, north-west Tanzania. Prior to the UCC 3,246 households were surveyed and 2,499 afterwards. Data on bed net ownership and usage, demographics of household members and household characteristics including factors related to socio-economic status were gathered, using an adapted version of the standard Malaria Indicator Survey. Specific questions relating to the UCC process were asked. The proportion of households with at least one ITN increased from 62.6% (95% Confidence Interval (CI) = 60.9-64.2) before the UCC to 90.8% (95% CI = 89.0-92.3) afterwards. ITN usage in all residents rose from 40.8% to 55.7%. After the UCC 58.4% (95% CI = 54.7-62.1) of households had sufficient ITNs to cover all their sleeping places. Households with children under five years (OR = 2.4, 95% CI = 1.9-2.9) and small households (OR = 1.9, 95% CI = 1.5-2.4) were most likely to reach universal coverage. Poverty was not associated with net coverage. Eighty percent of households surveyed received LLINs from the campaign. The UCC in Muleba district of Tanzania was equitable, greatly improving LLIN ownership and, more moderately, usage. However, the goal of universal coverage in terms of the adequate provision of nets was not achieved. Multiple, continuous delivery systems and education activities are required to maintain and improve bed net ownership and usage.\ud \u

Neuronal RARβ signaling modulates PTEN activity directly in neurons and via exosome transfer in astrocytes to prevent glial scar formation and induce spinal cord regeneration

Failure of axonal regeneration in the central nervous system (CNS) is mainly attributed to a lack of intrinsic neuronal growth programs and an inhibitory environment from a glial scar. Phosphatase and tensin homolog (PTEN) is a major negative regulator of neuronal regeneration and, as such, inhibiting its activity has been considered a therapeutic target for spinal cord (SC) injuries (SCIs). Using a novel model of rat cervical avulsion, we show that treatment with a retinoic acid receptor β (RARβ) agonist results in locomotor and sensory recovery. Axonal regeneration from the severed roots into the SC could be seen by biotinylated dextran amine labeling. Light micrographs of the dorsal root entry zone show the peripheral nervous system (PNS)–CNS transition of regrown axons. RARβ agonist treatment also resulted in the absence of scar formation. Mechanism studies revealed that, in RARβ-agonist-treated neurons, PTEN activity is decreased by cytoplasmic phosphorylation and increased secretion in exosomes. These are taken up by astrocytes, resulting in hampered proliferation and causing them to arrange in a normal-appearing scaffold around the regenerating axons. Attribution of the glial modulation to neuronal PTEN in exosomes was demonstrated by the use of an exosome inhibitor in vivo and PTEN siRNA in vitro assays. The dual effect of RARβ signaling, both neuronal and neuronal–glial, results in axonal regeneration into the SC after dorsal root neurotmesis. Targeting this pathway may open new avenues for the treatment of SCIs. SIGNIFICANCE STATEMENT Spinal cord injuries (SCIs) often result in permanent damage in the adult due to the very limited capacity of axonal regeneration. Intrinsic neuronal programs and the formation of a glial scar are the main obstacles. Here, we identify a single target, neuronal retinoic acid receptor β (RARβ), which modulates these two aspects of the postinjury physiological response. Activation of RARβ in the neuron inactivates phosphatase and tensin homolog and induces its transfer into the astrocytes in small vesicles, where it prevents scar formation. This may open new therapeutic avenues for SCIs

Passage and concentration-dependent effects of Indomethacin on tendon derived cells

<p>Abstract</p> <p>Background</p> <p>Non-steroidal anti-inflammatory drugs (NSAID) are commonly used in the treatment of tendinopathies such as tendonitis and tendinosis. Despite this, little is known of their direct actions on tendon-derived cells. As NSAIDs have been shown to delay healing in a number of mesenchymal tissues we have investigated the direct effects of indomethacin on the proliferation of tendon-derived cells.</p> <p>Results and Discussion</p> <p>The results obtained were dependent on both the type of cells used and the method of measurement. When measured using the Alamar blue assay, a common method for the measurement of cell proliferation and viability, no effect of indomethacin was seen regardless of cell source. It is likely that this lack of effect was due to a paucity of mitochondrial enzymes in tendon cells.</p> <p>However, when cell number was assessed using the methylene blue assay, which is a simple nuclear staining technique, an Indomethacin-induced inhibition of proliferation was seen in primary cells but not in secondary subcultures.</p> <p>Conclusion</p> <p>These results suggest that firstly, care must be taken when deciding on methodology used to investigate tendon-derived cells as these cells have a quite different metabolism to other mesenchymal derive cells. Secondly, Indomethacin can inhibit the proliferation of primary tendon derived cells and that secondary subculture selects for a population of cells that is unresponsive to this drug.</p