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Experimental and Theoretical Analysis of Nonlinear Triboelectric Energy Harvester for Frequency Up-Conversion Applications
Get PDFWith the development of micro-sensors and wireless applications, energy harvesting has become an effective method for self-powering. However, ambient energy is only limited to below 100Hz, which restricts the energy harvester designs to this range resulting inan impractical bulky and large-scale harvester. Therefore, in this thesis, we investigatedfrequency Up and Down conversion energy harvesters to benefit from the high-frequency oscillations and transferred them to the ambient vibration ranges. Toward this, the triboelectric transduction mechanism has been utilized for a frequency-up conversion for energy harvesting applications, while the piezoelectric transduction mechanism is used for frequency-downconversion for mass sensing applications. The performance of Vibro-impact triboelectric energy harvesting from low frequency using frequency up-conversion has been investigated theoretically and experimentally validated. The structure consists of two cantilever beams, one with a low natural frequency (Low-Frequency Beam (LFB)) and the other with a high natural frequency (High-Frequency Beam(LFB)). The two beams are coupled through repulsive magnetic force between two magnets attached as tip masses of the beams and facing each other at the same polarity. The HFB tip magnet acts as an upper electrode of a triboelectric energy harvester, while a PDMS insulator is attached to a lower electrode. When the structure is subjected to base excitation,the triboelectric layers generate an electrical signal via contact-separation impact motion between the triboelectric’s layers. The magnetic coupling converts low-frequency vibrations to high-frequency self-oscillations, and an electrical signal is generated at the LFB resonance. By controlling the distance between the two magnets, the structure will vibrate in eithermono or bistable oscillations. A lumped parameter model of a two-degree of freedom system is proposed to simulate the dynamic behavior and the generated electrical signal. The static and dynamic behaviors are investigated at different separation distances selected to cover the monostable, transition, and bistable regions. In addition, a parametric numerical analysisfor enhancing the electrical output and optimizing the harvester functionality. This study shows the feasibility of utilizing Vibro-impact triboelectric energy harvesting for frequency up-converting applications from ambient vibrations. Since the ambient vibrations are below 100 Hz while most machines and equipment operaterelatively at high frequencies (more than 70 Hz), we also propose a theoretical study to harvest energy from high frequencies using a frequency-down bistable piezoelectric energy harvester mechanism. We investigate the energy harvesting benefit in the down-conversion of a high-frequency signal to a low-frequency signal utilizing magnetic coupling. A high-frequency driving beam triggers a low-frequency generating beam. We use a spring-mass-damper equivalent model to understand the operation mechanism of the proposed piezoelectric vibration energy harvester. Based on the theoretical model, the static and dynamic effect of magnetic nonlinearity on the performance of the proposed piezoelectric vibration energy harvester is numerically analyzed. The targeted applications are the down-conversion and the filtering of high frequencies and mass sensing, particularly the harvester’s behavior for mass sensing applications
FUNCTIONAL IMPACT OF ETHYL-β-D-GLUCURONIDE ON MYCOBACTERIUM TUBERCULOSIS STIMULATED LUNG MACROPHAGES
Get PDFChronic alcohol abuse has been shown to alter immune defense mechanisms in humans and mice which makes the host susceptible to infections, including Mycobacterium tuberculosis (Mtb) infection. However, limited information is available on the mechanisms involved in alcohol-mediated host immune system dysfunction.
In this study, we determined the effects of ethyl-β-d-glucuronide (EtG), an alcohol-derived metabolite, on immune response of mice lung macrophages. We measured cytokine and chemokine production by gamma-irradiated mtb (γ-mtb) stimulated mice lung macrophages in the presence or absence of EtG. We also determined the effect of EtG on the metabolic state of γ-mtb stimulated mice lung macrophages.
We found that EtG inhibited secretion of IL-10 and enhanced production of macrophage inhibitory protein (MIP-1ß). We also found that EtG significantly inhibits oxidative phosphorylation of lung macrophages stimulated with γ-mtb
Weaving Layers of Learning: Multiplex Learning Networks in the Workplace
Get PDFThe multidimensional characteristic of learning has received little attention in the network literature, resulting in fragmented empirical evidence on learning networks. To address this gap, we introduce a framework that allows a better understanding of the multidimensionality of learning networks by employing the concept of multiplexity in the network literature. Our proposed conceptual framework for multiplex learning networks includes a 3-E typology (exploration, exploitation, and exaptation), which serve as distinct layers within the multiplex networks. We also provide a hypothetical scenario to demonstrate the potential of our multiplex learning networks framework for HRD scholars and practitioners. Moreover, we extend our framework to a multilevel model that connects individual-level learning relationships to team-level relationships. Our framework’s theoretical and practical implications are discussed, and future research directions are suggested
Comparison of oxygen supplementation in very preterm infants: Variations of oxygen saturation features and their application to hypoxemic episode based risk stratification
Get PDFBackground: Oxygen supplementation is commonly used to maintain oxygen saturation (SpO2) levels in preterm infants within target ranges to reduce intermittent hypoxemic (IH) events, which are associated with short- and long-term morbidities. There is not much information available about differences in oxygenation patterns in infants undergoing such supplementations nor their relation to observed IH events. This study aimed to describe oxygenation characteristics during two types of supplementation by studying SpO2 signal features and assess their performance in hypoxemia risk screening during NICU monitoring. Subjects and methods: SpO2 data from 25 infants with gestational age 0.80, F1 score \u3e 0.60 and specificity \u3e0.85 at observation times ≥ 1 h. Finally, we proposed a framework for risk stratification of infants using a cumulative risk score for continuous monitoring. Conclusion: Analysis of oxygen saturation signal routinely collected in the NICU, may have extensive applications in inferring subtle changes to cardiorespiratory dynamics under various conditions as well as in informing clinical decisions about infant care
CELLULOSE MATERIALS FOR DRUG DELIVERY APPLICATIONS
No full textNon-healing wounds are a growing global public health concern due to inadequate or ineffective therapeutic products available. Cellulose-based biopolymers are attractive wound dressing materials due to their biocompatibility, biodegradability, non-toxicity, and cost-effectiveness. This study aims to design and fabricate solid dosage formulations using carboxymethyl cellulose (CMC) and ethyl cellulose (EC) to facilitate multi-stage releases of phenytoin (PHT) and tetracycline hydrochloride (TCH) from plain carriers, fibers/films composites, and layer-by-layer fiber composites. Results from in vitro drug release assays demonstrated a time-dependent release up to 8 hours from PHT-loaded EC fibers, while TCH-loaded CMC films exhibited a rapid release within 5 minutes. In fiber-in-film composites, EC fibers were encapsulated in CMC films resulting in slow release of PHT, while hydrophobic EC fibers protected TCH release from CMC films within 5 hours in fiber-on-film composites. Drug release from layer-by-layer fiber composites showed dependence on composite arrangements and core/shell flow rate ratios. In general, through the understandings of drug releases from EC fibers and CMC films, fibers/films composites and layer-by-layer fibers composites were fabricated to provide a solution in customizable multi-stage drug release in drug delivery for wound healing applications
THE ROLE AND EFFECTIVENESS OF RESPONSE TO INTERVENTION TO IMPROVE ELEMENTARY STUDENTS’ READING SKILLS AND ABILITIES
Get PDFElementary students at a local elementary school were having reading difficulties and demonstrated a decreased performance on intervention measures, formal and summative assessments. Success in reading is imperative because students must read the content throughout their educational career and students must read the content on state assessments. Students’ success on state assessments determines placement of future intervention groupings in the next grade level, eligibility in extra-curricular activities and ultimately eligibility for high school graduation. The purpose of this evaluation study was to evaluate a pre-existing program to examine whether the implementation and use of Response to Intervention (RTI) was effective in improving students’ reading abilities and skills for elementary students performing below grade level. The research questions addressed teachers training and understanding for RTI as it applied to student’s reading performance in the grade level course. The research design was a mixed- methods design. This evaluation study had two phases. Phase one of the study was the evaluation of the problem of practice. Phase two of the study was the evaluation of an intervention to address the problem of practice. Data were collected from semi-structured interviews and informal observations (not related to teacher evaluation) with ten educators, one instructional specialist, and RTI data. In addition, data were collected from classroom formative assessments, district summative assessments, and state level summative assessments. The data indicate that the evaluation of the problem of practice RTI was not effective in improving students’ reading performance. Additionally, the data indicate from the evaluation of the intervention indicate RTI was effective in improving student’s reading abilities. The implications for change include better initial RTI training, improved RTI implementation coaching, improved fidelity of RTI implementation, improved students’ reading abilities and scores on district and state assessments
IDENTIFICATION OF BIOMARKERS OF SUB-LETHAL ALGAL TOXIN EXPOSURE IN ATLANTIC SALMON (SALMO SALAR) AND CHINOOK SALMON (ONCORHYNCHUS TSHAWYTSCHA) USING DIFFERENTIAL GENE EXPRESSION ANALYSIS
Get PDFAtlantic Salmon (Salmo salar) and Chinook Salmon (Oncorhynchus tshawytscha) are important culturally, recreationally, economically, and are a common aquaculture species in Canada and the United States. In the Pacific Northwest, blooms of toxic algae result in millions of dollars annually in losses for salmonid aquaculture producers. Blooms of harmful cyanobacteria produce microcystins which have been linked to net-pen liver disease which has large financial impacts on net pen salmon operations. Microcystin-LR, the most toxic variant, bioaccumulates in the liver and disrupts normal cellular activity by inhibiting protein phosphatases leading to deleterious effects on growth, immune status, and liver function. To minimize economic loss and improve animal welfare, salmonid producers have interest in using biomarkers of sub-lethal microcystin exposure to mitigate these impacts. RNA-sequencing was performed on liver samples from Atlantic and Chinook Salmon fed algal paste containing microcystin-LR in order to evaluate changes in gene expression caused by toxin exposure. The transcriptome response was examined at several time points following exposure to determine the most useful candidate biomarkers and to evaluate windows of detection. These biomarkers can serve as early warning signs that will allow aquaculture managers to decide to harvest early to avoid large mortality events caused by these algal toxins. Additionally, the biomarkers identified in this study have potential to be utilized across salmonid species for fish species broadly. Complementing previous microcystin research on fish, this study reports many differentially expressed genes related to the cell cycle, microtubule integrity, apoptosis, oxidative stress, inflammation, and metabolism
Oral Sucrose and the Relation to Neonatal Pain Perception
Get PDFPain is “an unpleasant sensory and emotional experience associated with actual or potential tissue damage” (Treede, 2018). The phenomenon of pain is a personal and unique experience that many of the world’s population has experienced in some form or fashion throughout their lifetime. Neonates are exposed to many painful procedures and/or situations due to various medical ailments that may require a neonatal intensive care unit (NICU) admission. Infants have a special place in the hearts of adults all over the world, and any interventions that would increase the likelihood of diminishing or removing perceived pain in this population are likely to be accepted and utilized by many. The PICOT question developed is: In infants who undergo painful procedures (P), how does the utilization of comfort measures with oral sucrose (I) compared to oral sucrose alone (C) affect pain experienced during or immediately post procedure (O) in a twelve-week data period (T)? The PICOT question at hand includes neonates and pain, both two topics that most people can relate or have interest in. The topic itself draws attention to the project because no one wants to see babies\u27 cry due to pain
Workplace Violence in Emergency Departments, Education and De-Escalation Training: A Benchmark Study
Get PDFMost people do not go to work and fear being assaulted or harassed daily. However, for emergency nurses in this county that is exactly what it has come to. Up to 96% of emergency department nurses state they have been verbally abused. This entails name calling, verbal threats, being shouted at and being sworn at. Anywhere from 25% to 60% of these nurses have had to face physical assaults while on the job. (Al-Aadi, 2020; Copeland & Henry, 2017; Grinberg, 2022; Li et al., 2019; McDermid et al., 2019). Physical assaults can include being spit on, slapped, punched, kicked, choked, objects thrown at them and even knives pulled on them (Grinberg, 2022 & Copeland & Henry, 2017). Per U.S. Bureau of Labor Statistics (2020), healthcare workers make up 73% of non-fatal workplace injuries due to violence. “Data shows American health care workers now suffer more nonfatal injuries from workplace violence than workers in any other profession, including law enforcement” (Boone, 2023). Al-Qadi (2020) stated, “This behavior has become so commonplace that it has become accepted as a standard occupational hazard of working in the ED”.
This country is facing a nursing shortage and emergency nurses are leaving the specialty or nursing all together because of the extreme amount of violence they face daily. Emergency nurses are highly skilled and trained and are an integral part of emergency services to a community. With a high rate of turnover in emergency nurses, we are facing a significant issue with the ability to safely care for emergency patients. Unless interventions are put into place to protect our nurses, things will only worsen and more nurses will be injury either emotionally, mentally, or physically
A Provider in Triage to Decrease “Left Without Being Seen”: A Benchmark Project
Get PDFAs Emergency Departments (ED) continue to fill and become crowed, the attention to care of each patient can be delayed or missed. Back flow into the ED can cause a bottleneck effect for patients coming in, which can lead to an increase in the number of patients who leave without being seen (LWBS). In order to combat the challenges of patient throughput that result in patients leaving prior to care, I am proposing the implementation of a provider in triage (PIT). By placing a provider, either physician or mid-level practitioner, in the triage area will allow patients to been seen and assessed faster. Once a patient is seen and orders are placed, care can be initiated. In addition, seeing patients at a faster rate will also help with the identification of the critically ill. Not only will the PIT be able to start orders, but a rapid assessment of patients will help acutely ill patients get out of the lobby. The goal is to see patients and have care started faster in order to avoid patients leaving without care, as well as provide better patient outcomes. Patients who leave before care can be initiated, increase both their risk for morbidity and mortality (Shah et al., 2020; Sember et al., 2021). Jesionowski et al., (2019) describes a statistic suggesting the LWBS rate for all ED visits in 2014 equated to 1.2%, which is equivalent to about 2.68 million patients. This not only increases the risk to the patient, but it can be detrimental to hospital revenue as well