bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors associated with participation in weight loss treatment for obesity among self-identified non-Hispanic black and non-Hispanic white women
Authors:   , Doshi Sapna D. , Lowe Michael R.
Published: July 2021

Research has found that non-Hispanic black (black) participants have higher attrition rates than non-Hispanic white (white) participants in behavioral weight loss programs. Exploratory predictor variables among two samples of black and white obese females ages 19 to 71 (Study 1: n=100 and Study 2: n=174) were entered into linear and logistic regressions with race/ethnicity and an interaction term to determine if there were differential factors between racial/ethnic groups related to number of sessions attended and attrition. Both studies used meal replacements for weight loss followed by randomization to different weight loss maintenance conditions. Study 1 involved inperson group treatment, and Study 2 involved individual, telephone-based treatment. In Study 1, black participants (n=37) attended significantly fewer sessions than white participants (n=63) and had higher rates of attrition as well; in Study 2 there was no significant difference between black (n=139) and white participants (n=35) in sessions at ended or attrition. When data from the two studies were combined, results similar to Study 1 were found. Significant main effects were found such that lower disinhibition and higher perceived hunger was associated with lower attendance. Additionally, higher BMI and better work quality of life was associated with worse participation. Significant interactions of predictor variables and race were found such that black participants higher in BMI attended fewer sessions and black participants who lost more weight early on in treatment attended more sessions. Black participants lower in age and white participants with better work quality of life had worse participation. These preliminary data provide insights into racial/ethnic differences in factors associated with participation and can guide future research to identify factors to address initially to promote participation in black and white participants in treatments using different formats.
The effect of regulatory T cells on an age-altered specific CD8 T cell response following influenza infection
Authors:   , Williams-Bey Yolanda , Murasko Donna
Published: July 2021

The elderly population is a major user of our health care resources. With this population of people growing faster than any other age group, it is important to find ways to reduce the increasingly high morbidity and mortality rates due to infections. Several studies have demonstrated that both aged mice and humans have a reduced CD8 T cell response to influenza infection. Further, it has been demonstrated that these alterations result from both intrinsic and extrinsic factors. Recently, it has been observed that there is an increase in the regulatory T cells (Treg cell) percentage in aged mice. No study has evaluated if this increase in Treg cells could be an extrinsic factor which suppresses the expansion and function of CD8 T cell responses during acute influenza infection. Therefore, we hypothesized that a major contributor to the extrinsic changes that effect T cell responses in aged mice are Treg cells. We compared the phenotype and function of Treg cells from aged and young mice. Interestingly in vitro depletion of Treg cells had no effect on CD8 T cell responses in young or aged mice. Further there appears to be no significant differences in the ability of Treg cells from aged mice to suppress specific CD8 T cells isolated from TCR transgenic (Tg) mice compared to Treg cells isolated from young mice. Although we found no differences in the function of Treg cells of aged compared to young mice in vitro, this does not mean that Treg cells do not demonstrate an age-associated differential impact in vivo following influenza infection. To evaluate the potential impact of Treg cells of aged mice on CD8 T cell expansion and function we studied the kinetics of Treg cells following influenza infection of young and aged mice. Following influenza infection Treg cells expand in aged but not young mice. Further the peak of CD8 T cell expansion and IFN-[gamma] production in aged mice coincides with contraction of expanded Treg cell percentage and activation. We believe that this increased expansion early during infection in aged mice interferes with CD8 T cell expansion and function.
Outcome Based Education and the Quest for Competency
Authors:   , Brooks Stephanie , Johnson Eric D. , Davey Maureen P.
Published: July 2021

For more than a decade the issue of provider competency has been linked to significant problems in the delivery of health care services. This in turn has increased attention towards evaluating the quality of education and clinical training in health care professional programs. In 2004, the American Association for Marriage and Family Therapy established core competencies (MFT CC) for the profession. Adopting clinical competency will require couple and family therapy (CFT) professional education programs, at a minimum to develop outcome-based educational approaches and become more adept at measuring CFT student's clinical competency and development over time. It further suggests CFT educators need to have competencies to develop and implement an outcome based curriculum. Yet, little is known about CFT faculty aptitude in this area. The primary aim of this study was to identify and describe CFT faculty' attitude, concerns, experiences, and perceptions about competency and outcome based education. Results of the study provide valuable information about how faculty are managing five years after the introduction of the MFT CC and the new COAMFTE standards. The CFT faculty clearly value both the MFT CC and OBE . The MFT CC are used to influence program curriculum and CFT faculty believe they will improve the clinical evaluation of students. The CFT faculty desire to be involved in the ongoing development of the MFT CC and want the AAMFT to offer more training. Furthermore, CFT faculty are seriously adopting an OBE paradigm despite reporting they received less than 5 hours of training in the approach. While CFT faculty found their institutions supportive of the OBE approach, the findings suggest they are overextended and stressed. The implications of the findings are discussed for both faculty and program development. Future directions for research are proposed including examining the similarities and differences between CFT faculty in doctoral and post-degree institute programs to better appreciate how the faculty from the COAMFTE accredited have responded to this paradigmatic shift.
Healthcare Information Technology and Medical Surgical Nurses
Authors:   , Moore An'Nita C. , Fisher Kathleen Mary
Published: July 2021

Currently, increasing numbers of hospitals and ambulatory care institutions in the United States are experiencing expanding use and diffusion of healthcare information technology (HIT), including more expansion toward the electronic health record (EHR). Considering nurses are responsible for documenting, interpreting, and acting upon the voluminous amount of data maintained by information systems, it is imperative that they efficiently utilize HIT by effectively analyzing the data it yields to aid in their clinical decision making. A few studies have addressed the relationship between nurses and information technology in practice, unfortunately the body of literature relative to the topic is narrow and was primarily explored prior to the proliferate implementation of EHRs. This study sought to explore two focal points with regards to the interaction between healthcare information technology and nurses, the first being how medical surgical nurses are utilizing HIT in their current clinical practice. The second aim was to examine the influence of HIT on nurses' clinical decision making. Utilizing qualitative content analysis, data from two homogeneous focus groups of novice and experienced nurses was analyzed to evaluate the identified research questions. Findings from data collected from both groups suggest that nurses' clinical decision making is not overtly influenced by the use of healthcare information technology. Five themes emerged that described nurses' experiences with the information technology. The following were identified as theme labels: (a) healthcare information technology as a care coordination partner, (b)healthcare information technology as a change agent in the care delivery environment, (c) healthcare information technology - unable to meet all the needs, of all the people, all the time, (d) curiosity about healthcare information technology - what other bells and whistles exist, and (e) big brother is watching. Nurses' use of new information technology is more reliant on its' ability to organize and coordinate care for assigned patient groups as opposed to guiding decision making. Results of this study suggests that a new care partnership has emerged as the provision of nursing care is no longer supplied by a single practitioner but rather by a paired team, consisting of nurses and technology.
Characterization of decellularized arterial conduits
Authors:   , Fitzpatrick John Charles , Capaldi Franco M.
Published: July 2021

Sterilization processes used on biologically-derived, intact arteries may change the vessel's structural integrity and biocompatibility from its native state. Remodeling processes that occur in biologically-derived vessels serve to restore homeostatic levels of shear and circumferential stresses, which arise from fluid flow and pressure loads. If the mechanical compliance of a decellularized artery changes from its native state, the vessel may be vulnerable to biological remodeling processes that occlude the vessel when used for small-diameter arterial bypass or replacement procedures. The effects of three distinct detergent-enzymatic decellularization protocols on porcine artery were characterized by mechanical and spectroscopic methods to evaluate cell removal efficacy, preservation of structural integrity, and altered mechanical behavior under physiological loading. Longitudinal porcine aortic strip samples were tested under uniaxial tension, and parameters optimized to a nonlinear rubber model were compared. Molecular-level changes between treated and untreated arterial tissue were assessed by observing shifts in Fourier Transform Infrared (FTIR) spectra processed by baseline-correction between amide I and II bands and optimized to Gaussian-Lorenztian curve distributions. Quasi-static inflation-extension tests were used to characterize effects of temperature and decellularization on the modeled distensibilities of native porcine carotid artery. Parameters for a nonlinear, orthotropic strain energy function were optimized to inflation-extension data to predict internal stresses at physiological loads. A four-step, 72-hour decellularizaton protocol that utilized TritonX-100, sodium-deoxycholate, RNase-A, DNase-I, and magnesium chloride as reagents was the most effective option for decellularizing porcine aorta. This protocol lysed all smooth muscle cells from porcine aorta and reduced the hyperelastic response of the vessel in the physiologic loading range. Analysis of FTIR spectra confirms that this decellularization method does not denature collagen protein structure in arterial tissue, but does alter intermolecular hydrogen bonding that supports the observed increase in bulk mechanical compliance. Three-dimensional mechanical characterization of porcine carotid artery suggests that room temperature testing conditions and the selected decellularization protocol increase arterial residual strains. Increased levels of residual strain increase the vessel's modeled distensibility and, consequently, its internal stresses. Use of a constitutive model that incorporates residual strains leads to better prediction of local circumferential stresses in comparison to mean circumferential stress approximations.
Effect of non-cognitive and social environmental factors on the retention of under-represented minority students in engineering and technology-related disciplines
Authors:   , Rocheleau Suzanne Elyse , Harvey Francis
Published: July 2021

The failure of American colleges and universities to retain African American, Hispanic and American Indian students in engineering and technology - related disciplines is a significant problem that poses a threat to America's global technological leadership. The purpose of this study was to examine the non-cognitive and university-related social and environmental factors that under-represented minority college students enrolled in engineering and technology-related disciplines believed had contributed to their academic success and college retention. Forty-nine current and former NACME Vanguard Scholars at the focus university were surveyed using an Internet-based research instrument and twelve participated in focus groups. The researcher-generated survey included the Non-Cognitive Questionnaire (NCQ), and replicated the studies of William E. Sedlacek, Ph. D. Results indicate that academic success and college retention could not be explained by background characteristics of race, gender, socioeconomic status, parental education, high school GPA and course pattern or SAT scores. Respondents credited non-cognitive abilities for their success and achieved above average scores on four non-cognitive ability scales. Campus support and advising programs were relevant to the development of noncognitive abilities. In particular, cohort participation provided a micro-environment that strengthened and supported participants, enabling them to achieve the academic and social integration necessary for academic success and college retention.
Curcumin loaded ultrasound contrast agents for drug delivery to tumor cells
Authors:   , Nagaraja Archana Sidalaghatta , Wheatley Margaret A.
Published: July 2021

Curcumin (diferuloylmethane) is obtained from Curcuma longa, a rhizome which has been used for centuries in traditional Indian and Chinese medicine and diet. This hydrophobic phenol has several documented biological and pharmaceutical activities (including anti-cancer effects). However, the low solubility and degradation of Curcumin at neutral pH limits its therapeutic potential. Encapsulating the drug in a hydrophobic core of a microbubble would prevent the drug from degradation, and permit site-specific delivery of Curcumin to tissue. Ultrasound targeted microbubble destruction is a non-invasive method of imaging tumors. Ultrasound contrast agents (UCA) are less than 6 [mu]m and can be designed to administer drugs. Ultrasound also transiently increases the permeability of cell membrane for drug uptake. The microbubbles used for this study range from 1-3 [mu]m and are made of surfactant-mixture with a gas core (of perfluorocarbon). The surfactants were chosen as they are shown to overcome drug-resistance of the tumor cells by inhibiting the Pglycoprotein. The goal of this study was to load Curcumin on surfactant-stabilized microbubbles without compromising on the echogenicity and stability of the microbubbles. Intrinsic fluorescence was used to quantify the amount of Curcumin loaded into the microbubbles. Cell studies were also conducted using two breast cancer cell lines to study cell-death.
Chemical bath deposition of semiconductor thin films & nanostructures in novel microreactors
Authors:   , McPeak Kevin M. , Baxter Jason B.
Published: July 2021

Chemical bath deposition (CBD) offers a simple and inexpensive route to deposit semiconductor nanostructures and thin films, but lack of fundamental understanding and control of the underlying chemistry has limited its versatility. CBD is traditionally performed in a batch reactor, requiring only a substrate to be immersed in a supersaturated solution of aqueous precursors such as metal salts, complexing agents, and pH buffers. Highlights of CBD include low cost, operation at low temperature and atmospheric pressure, and scalability to large area substrates. In this dissertation, I explore CBD of semiconductor thin films and nanowire arrays in batch and continuous flow microreactors. Microreactors offer many advantages over traditional reactor designs including a reduction in mass transport limitations, precise temperature control and ease of production scale-up by "numbering up". Continuous flow microreactors offer the unique advantage of providing reaction conditions that are time-invariant but change smoothly as a function of distance down the reaction channel. Growth from a bath whose composition changes along the reactor length results in deposited materials whose properties vary as a function of position on the substrate, essentially creating a combinatorial library. These substrates can be rapidly characterized to identify relationships between growth conditions and material properties or growth mechanisms. I have used CBD in a continuous flow microreactor to deposit ZnO nanowire arrays and CdZnS films whose optoelectronic properties vary as a function of position. The spatially-dependent opto-electronic properties of these materials have been correlated to changes in the composition, structure or growth mechanisms of the materials and ultimately their growth conditions by rigorous spatial characterization. CBD in a continuous flow microreactor, coupled with spatial characterization, provides a new route to understanding the connection between CBD growth conditions and the resulting optoelectronic properties of the film. The high surface-to-volume ratio of a microreactor also lends itself to in situ characterization studies. I demonstrated the first in situ x-ray absorption fine-structure spectroscopy (XAFS) study of CBD. The high sensitivity and ability to characterize liquid, amorphous and crystalline materials simultaneously make in situ XAFS spectroscopy an ideal tool to study the CBD of inorganic nanomaterials.
The Effectiveness of Art Museums Marketing Late Night Programming to the Twenty-Five to Forty Age Group
Authors:   , Cretaro Amy Solomon , Moore Brian
Published: July 2021

Over the last twelve years the art museum field has witnessed the birth of Late Nightprogramming throughout the country, geared toward garnering a younger audience. As theAmerican population ages, arts administrators across the country are actively pursuing 25 to 40 year-olds as the next generation of patrons and philanthropists. Art museums continually face diverse challenges in an effort to bring new audiences into their institutions. Evening mixers, along with an overhaul of institutional marketing are clear ways in which museums are seeking out young Americans. By conducting the survey of the fourteen art museums with relevantprogramming, holding three interviews, two site visits and internet research, I explored the various reasons why late night programming is held and how it is marketed to this audience segment, and if indeed 25-40 age group attends. As this study substantiates even without complete data on how late night program attendees and members move up the giving and philanthropic ladder over time; if you hold after hours programming the twenty five to fortydemographic will come.
Temperature-dependent transmission line models for electric power systems and their impacts on system studies
Authors:   , Cecchi Valentina , Miu Karen Nan
Published: July 2021

Electric power transmission line models for large scale system studies are characterized by uniformly distributed parameters or a lumped parameter configuration. These models have been historically developed for studies under nominal operating conditions. The following assumptions are often made: uniform current density, constant material characteristics, and constant external conditions, including temperature. However, in recent years, the increased use of renewable energy resources and corresponding enabling technologies has had an impact on the electric power system, and several previous operating assumptions are no longer valid. This thesis focused on electric power lines as a critical network component of the power system, and aimed at developing line models to be used in steady-state system analysis applications. By relaxing historical modeling assumptions and by taking into account parameters not previously considered, more accurate results are expected by the decision-making tools. Specifically, two parameters were considered:1. Environmental conditions - ambient temperature gradients along a line,2. Electrical frequencies - the expected increase in non-fundamental frequencies due to augmented use of power electronic devices. Contributions include formulating an optimization problem to incorporate these parameters into static line models. Then, a focus was put on developing a line modeling approach to take into account ambient temperature variations along the line. The proposed line models are temperature-dependent in terms of both structure and line parameters; therefore, they enable capturing of temperature effects, including more accurate determination of power handling capabilities. The line modeling approach was automated and incorporated into multi-bus system analysis tools. The proposed models' impacts on large-scale, steady-state system studies, such as power flow analysis, were investigated.
Generation of the sodium/myo-inositol cotransporter 1 (Slc5a3) gene murine knockout model, characterization of its lethal phenotype, and revision of the 'inositol depletion hypothesis'
Authors:   , Buccafusca Roberto , McEachron Donald L. , Berry Gerald T.
Published: July 2021

Myo-inositol (Ins) is a ubiquitous hexahydroxycyclohexane in living organisms, and the most abundant in mammalian cells of all nine possible stereoisomers along with scyllo-, neo-, epi-, muco-, allo-, cis-, and the enantiomers, D-chiro and L-chiro. Ins is an important osmolyte and a key component of phosphatidylinositol (PtdIns), unique in the family of phospholipids in that its Ins headgroup can be further phosphorylated to generate various phosphoinositides. Among them, phosphatidylinositol-4,5-bisphosphate (PtdIns-4,5-P2) is involved in important signal transduction events. Ins's cellular uptake is carried out by a system of specific membrane transporters, of which the SLC5A3 (SMIT1), a Na⁺/myo-inositol cotransporter, is the one with the highest affinity for the polyol. The principle aim of my thesis work is to test the widely accepted "myo-inositol depletion hypothesis" envisioned to explain the mechanism of action of lithium, complications of diabetes and hereditary galactosemia. This assumption, which states that a reduction of intracellular myo-inositol results in a decreased PtdIns synthesis, and therefore a disruption of cellular signaling, had never been tested by direct measurements of PtdIns. To investigate the effect of Ins deficiency at the cellular level, a murine knockout model of the Slc5a3 gene encoding the Na⁺/Ins cotransporter was generated and studied. The resulting Slc5a3-null mice die shortly after birth, although the phenotype can be rescued by supplementation of 1% Ins in the drinking water of the pregnant dam. The rescued Slc5a3 knockout mice survive only if the Ins enriched water treatment continues until weaning, 14 days after birth. My work shows that a 69.7% reduction in myo-inositol is responsible for a 47% reduction of PtdIns in the murine Slc5a3-null fetus at embryonic stage 10.5, but the hypothesis proves to be invalid at later stages of development, at embryonic stages 14.5 and at 18.5, and through adulthood. The work outlined in this dissertation also shows that the 'Ins depletion hypothesis', as it has been proposed, proves to be invalid since Ins levels in mammalian tissues have never been shown to be reduces to the degree observed in Slc5a3 knockout mouse model used in my study.
Molecular simulations of HIV-1 gp41 protein-membrane interactions
Authors:   , Gangupomu Vamshi K. , Abrams Cameron F.
Published: July 2021

Cellular and viral membrane fusion is a critical process during viral infection. The HIV-1 surface envelope glycoprotein (gp41) anchored in the cholesterol-rich host cell derived viral membrane is responsible for mediating membrane fusion between the viral and target-cell membranes. The objective of this thesis is to understand the role of cholesterol and gp41, specifically the membrane spanning domain (MSD) and the two ectodomain heptad repeats (N-terminal heptad repeat and C-terminal heptad repeat), during membrane fusion using all-atom molecular modeling. The 27-residue membrane-spanning domain (MSD) of the HIV-1 glycoprotein gp41 bears conserved sequence elements crucial to the biological function of the virus, in particular a conserved mid-span arginine Arg694. We found that the MSD assumes a stable [alpha]-helical conformation and metastable kinked conformations that differ depending upon whether Arg694 side-chain snorkels towards the exoplasmic or endoplasmic side of the viral membrane. It was observed that when the Arg694 side-chain snorkels towards the endoplasmic headgroups the MSD assumes a kinked conformation that was hypothesized from experimental studies. Moreover, we found significant local thinning of the membrane and penetration of water molecules into the membrane core in the presence of mid-span Arg694. The presence of cholesterol in the lipid membrane was found to assist in better anchoring of a non-polar structure in the membrane while increasing the free-energy of membrane destabilization. Mechanically destabilizing a cholesterol-rich lipid membrane also resulted in the formation of a larger rupture pore compared to a pure POPC lipid bilayer. Model built structures of the gp41 ectodomain were then used to simulate folding of the gp41 pre-fusion intermediate into a stable six-helix bundle. These models provided important insights into the mechanism of folding and the specific interactions involved during folding. Membrane fusion requires that the opposing membranes are brought into proximity and destabilized to facilitate lipid mixing. The membrane lipids and fusion proteins in both the membranes play important roles in facilitating membrane fusion. In this work we showed specific roles cholesterol and HIV-1 gp41 play in priming the viral membrane to promote fusion.
Scaffolds with oriented microchannels for angioneural regenerative engineering
Authors:   , Saglam Aybike , Lelkes Peter I.
Published: July 2021

Spinal cord injury (SCI) affects over 12,000 people annually and, due to limited therapeutic options, results in an estimated 1.3 million people living with chronic motor dysfunction or paralysis in the U.S. The medical costs associated with SCI can pose significant financial burden to patients (estimated at 2 million dollars in a lifetime-NSCICS). Finding a therapeutic strategy for repair of SCI would dramatically improve quality of life for these patients as well as ease the costs associated with chronic care. Prior studies have shown that on non-structured substrates, oriented axonal growth is very poor; axons tend to grow erratically and axon connection pathways cannot find and connect to their target neurons. Additionally spinal cord development, and presumably spinal cord regeneration requires angiogenesis for nutrient delivery as well as regulation of neuronal growth through paracrine signaling. This is supported by previous studies that showed increased micro-vessel density correlates with regeneration and functional recovery in spinal cord tissue. Based on these finding this study focuses on combining structural support for directed axonal growth with angiogenic cues for the purpose of enhancing SCI repair. It hypothesizes that the crosstalk between the vascular and the nervous systems, i.e., between cues that lead to angiogenesis and neuritogenesis is crucial for axonal regeneration across a spinal cord lesion. To test this hypothesis, a scaffold is evaluated for promoting neuritogenesis in vitro by seeding its longitudinally oriented 3D pores with endothelial cells prior to seeding with neural-crest derived PC12 cells. This study designed and tested a biodegradable, genipin cross-linked gelatin scaffold by using a controlled uniaxial freezing technique followed by lyophilization to improve mechanical properties of the scaffold and to generate longitudinal microporous channels. The scaffold had mechanical properties similar to those of the rat spinal cord with elastic moduli of (~51kPa), and it supported growth and differentiation of endothelial cells and PC12 cells. An "angioneural tissue" was generated by first seeding endothelial cells in the scaffold to generate a monolayer lining the channel walls, followed by seeding with neuronal PC12 cells a week later. In support of the hypothesis, the presence of endothelial cells facilitated the differentiation of nerve growth factor (NGF)-induced PC12 cells significantly leading to enhanced PC12 cell survival and neuritogenesis. Our results are promising for the promotion of neuritogenesis through endothelial cell-derived cues (angioneural crosstalk, i.e., concomitantly promoting ngiogenesis and neuritogenesis), which may facilitate tissue regeneration and recovery after spinal cord injury.
Filling and chemical modification of carbon nanotubes
Authors:   , Naguib Nevin N. , Gogotsi Yury
Published: July 2021

In order to utilize carbon nanotubes in nanofluidic device applications as well as nanocomposite reinforcement, more research on filling, surface chemistry and interaction of carbon nanotubes with liquids must be done. Understanding the penetration of fluids into nanochannels is important for the efficient storage of liquids as well as composite manufacturing. Transmission electron microscopy, Infrared spectroscopy, mass spectroscopy have been used in this research as the investigation tools. In this research, an autoclave high temperature-high pressure system was built. Carbon nanotubes were shown to be successfully filled by using this autoclave treatment. The conditions have been determined for the filling of different types of carbon nanotubes and carbon nanofibers of different diameters with water and ethylene glycol. Water has been demonstrated and confirmed to be trapped inside heat-treated carbon nanofibers of 50-200 nm in diameter, chemical vapor deposited nanotubes of 2.5-5 nm in diameter, and possibly double wall carbon nanotubes and single wall carbon nanotubes with diameters of 1.5-2 nm. At the scale of 5 nm or less, water molecules were observed in-situ below the continuum limit, where they were shown to form clusters and chains. The effect of diameter on water filling of chemical vapor deposited nanotubes is observed. These tubes have a much less filling yield (15%) compared to heat-treated carbon nanofibers, which have a 30% filing yield. Optimum conditions of water filling have been determined to be 650°C and 80 MPa for most nanotubes studied in this research. Conversely, when ethylene glycol was mixed and treated with carbon nanotubes by autoclave conditions, it tends to polymerize and possibly form a polyester outside and inside of the nanotubes. Besides studying the filling of carbon nanotubes with water and ethylene glycol, careful investigation of surface structure of different types of carbon nanotubes have been performed. Hydrothermal nanotubes are shown to have hydrophilic surfaces with at least carboxyl and hydroxyl groups existing.
Mechanics and development of tarsal cartilage anlagen
Authors:   , Mahmoodian Roza , Capaldi Franco M. , Siegler Sorin
Published: July 2021

Fetal cartilage anlage provides a framework for endochondral ossification and organization into articular cartilage. Deficiency or retardation of these developmental processes causes musculoskeletal deformities. The mechanical environment can modulate development, highlighting the indispensable role of accurate mechanical models in reliable biomechanical analyses and improving shortcomings of models of morphogenesis. While much attention has been paid to the mechanical characterization of articular and growth plate cartilage, the need for investigating the developing cartilage anlage mechanics has not been answered. Additionally, finite element (FE) models are required for studying problems of soft tissue as they generally involve complex geometries, boundary conditions, and/or complicated material behavior. This makes the importance of FE implementation of material models evident. Furthermore, with the work on osteogenesis of limbs being predominantly focused on long bones, studying the mechanisms of endochondral ossification in short bones seems invaluable to understanding the normal growth patterns and etiology of their deformities. One such important case is the clubfoot deformity which can lead to severe handicap if untreated. The Ponseti technique, based on serial manipulation and immobilization, is commonly used to treat infant clubfoot. Despite the numerous studies describing theses deformities, little information is available on the correction mechanisms under this treatment method. In the present study, the mechanical properties of developing cartilage anlage in near full-term human fetal talus were determined in confined and unconfined compression indicating the cartilage under study was softer and more permeable than e.g. articular cartilage. A straightforward method was formulated to model cartilage under large deformations using the strain energy function of the finite deformation biphasic theory, by directly incorporating the commonly extracted mechanical properties. A unique "human experiment" was conducted to elicit the effects of manipulation therapy of new-born clubfooted infants undergoing Ponseti treatment. Correction of anlagen deformities and positional relationships was observed in all patients. Ossification was enhanced under treatment, especially in the talus and cuboid, and was faster in clubfoot than normal. Patient-specific FE analysis was conducted suggesting the presence of a positive correlation between both the strain energy density and the pore fluid velocity magnitude with the amount of bone added between each two visits.
Identifying the substrate for successful robot rehabilitation in adult rats spinalized as neonates
Authors:   , Udoekwere Ubong Ime , Giszter Simon F.
Published: July 2021

Approximately 200,000 people live with spinal cord injury (SCI) worldwide, and more than 10,000 new cases are reported yearly. SCI patients suffer neurological deficits and severe functional loss below the level of injury, especially in cases where the cord is completely severed. After SCI, secondary injury processes worsen the damage, subsequently limiting the spinal cord's endogenous response to spontaneously repair and regenerate axons. This limits recovery of function. As a result, additional therapeutic interventions are often required to improve recovery. Unfortunately, there are no fully restorative therapies for SCI, but a lot of promising therapeutic techniques are currently being explored in animal models in labs across the globe. One promising animal model for studying SCI recovery is a thoracic spinal cord spinalization in neonatal rats. This injury completely inhibits hindlimb stepping and locomotion. Using this model, spinalized neonates (NTX) manage to recover autonomous hindlimb weight supported (HWS) stepping as adults. Furthermore, intracortical microstimulation, cortical lesioning, and locomotor kinematic findings from the Giszter lab have identified cortical reorganization of trunk representation and trunk control as essential elements for NTX recovery. Approximately 200,000 people live with spinal cord injury (SCI) worldwide, and more than 10,000 new cases are reported yearly. SCI patients suffer neurological deficits and severe functional loss below the level of injury, especially in cases where the cord is completely severed. After SCI, secondary injury processes worsen the damage, subsequently limiting the spinal cord's endogenous response to spontaneously repair and regenerate axons. This limits recovery of function. As a result, additional therapeutic interventions are often required to improve recovery. Unfortunately, there are no fully restorative therapies for SCI, but a lot of promising therapeutic techniques are currently being explored in animal models in labs across the globe. One promising animal model for studying SCI recovery is a thoracic spinal cord spinalization in neonatal rats. This injury completely inhibits hindlimb stepping and locomotion. Using this model, spinalized neonates (NTX) manage to recover autonomous hindlimb weight supported (HWS) stepping as adults. Furthermore, intracortical microstimulation, cortical lesioning, and locomotor kinematic findings from the Giszter lab have identified cortical reorganization of trunk representation and trunk control as essential elements for NTX recovery.
Mechanistic understanding of P-gp mediated transport and inhibition kinetics across a confluent monolayer of MDCKII-hMDR1 cells using a mass action kinetic model
Authors:   , Lumen Annie Albin Melba Lumine , Bentz Joseph Edward
Published: July 2021

The purpose of this work is to investigate several aspects of transporter-mediated interactions in a physiologically relevant model system and to gain a clear mechanistic understanding of the same using a mass action kinetic model. We have first shown that the parameters determining the potency of an inhibitor, IC50 & KI are not the same for P-gp and that IC50 overestimates KI. The quantitative relationship between them is derived and the physical mechanism of overestimation, explained. This sensitive modeling tool was further used for the kinetic identification of other transporters in addition to P-gp in several confluent cell monolayer systems. It was shown that a simple IC50 plot has more than one inhibition events convolved in them and the model was used to separate the individual contributions. This is of clinical relevance for the accurate assessment of transporter mediated drug-drug interaction risks. We have also derived an exact equation for measuring the passive permeability coefficients of compounds that show significant drug loss. Such measurements would help us carefully delineate the passive component from the total transport and describe the P-gp mediated transport of these compounds unambiguously. In summary, such an understanding of drug -transporter relations in vitro obtained as a part of this thesis work is valuable for making accurate predictions of drug disposition in vivo, aiding the ability to make informed decisions during the several stages of drug discovery and development.
Attempted Bismuth Ferrite Sensitization of Nanostructured Titanium Dioxide and/or Zinc Oxide for Photovoltaic Applications
Authors:   , Burger Jonadan Ando , Spanier Jonathan E.
Published: July 2021

Bismuth ferrite (BFO) is a 'mid-range' band gap, multiferroic (ferroelectric, antiferromagnetic) material of interest in numerous applications. Though its use in photovoltaic applications has been investigated with interesting result, such a material has not yet been used as a photovoltaic sensitizer/thin absorber in sensitized solar cell (SSC) or extremely thin absorber solar cell (eta-SC) devices. A band gap (E_g~2.2-2.8eV) within the visible light range (albeit high) makes BFO a potential candidate for such application. Moreover, BFO is ferroelectric (E_c ~500-600kV/cm, P_r = 60[mu]C/cm²), which provides the material with an internal electric field (which can be directed/'poled' towards one electrode or another in a(n) SSC/eta-device), which may provide an additional mechanism for either or both charge separation and transport. CuSCN/ZnO, CuSCN/TiO₂, CuSCN/Bi-Fe-Zn-O/ZnO, CuSCN/BFO/TiO₂ thin-film 'sandwich-like' structures were fabricated on transparent-conducting-oxide-glass (TCO) substrates, via combinations of electrodeposition and suspension or sol-gel (requiring 'high temperature' for crystallization) dip-coating, and characterized at various stages of production to assess material/phases present, optical absorbance characteristics, and preliminary electronic device performance. 'High-temperature' heat treatments in air or N₂ of Bi-Fe-Zn-O/ZnO samples result in films yielding crystalline non-BFO phases, while O₂ annealing of similar samples appear promising. BFO has been successfully crystallized on nearly-pure anatase TiO₂ synthesized/deposited two ways, as well as on F:SnO₂-glass. Moreover, BFO is found to enhance absorbency in at least a portion the visible portion of the electromagnetic spectrum. Such are promising signs that thin-absorber-PV devices based on either TiO₂ or ZnO may be viable for development in the near future.
On the role of entropy in the protein folding process
Authors:   , Hoppe Travis , Yuan Jian-Min
Published: July 2021

A protein's ultimate function and activity is determined by the unique three-dimensional structure taken by the folding process. Protein malfunction due to misfolding is the culprit of many clinical disorders, such as abnormal protein aggregations. This leads to neurodegenerative disorders likeHuntington's and Alzheimer's disease. We focus on a subset of the folding problem, exploring the role and effects of entropy on the process of protein folding. Four major concepts and models are developed and each pertains to a specfic aspect of the folding process: entropic forces, conformationalstates under crowding, aggregation, and macrostate kinetics from microstate trajectories. The exclusive focus on entropy is well-suited for crowding studies, as many interactions are nonspecific. We show how a stabilizing entropic force can arise purely from the motion of crowders in solution. In addition we are able to make a a quantitative prediction of the crowding effect with animplicit crowding approximation using an aspherical scaled-particle theory. In order to investigate the effects of aggregation, we derive a new operator expansion method to solve the Ising/Potts model with external fields over an arbitrary graph. Here the external fields are representative of the entropic forces. We show that this method reduces the problem of calculating the partition function to the solution of recursion relations. Many of the methods employed are coarse-grained approximations. As such, it is useful to have a viable method for extracting macrostate information from time series data. We develop a method to cluster the microstates into physically meaningful macrostates by grouping similar relaxation times from a transition matrix. Overall, the studied topics allow us to understand deeper the complicated process involving proteins.
A two-location lateral transshipment problem with customer switching
Authors:   , Liao Yi , Banerjee Avijit , Shen Wenjing
Published: July 2021

Lateral transshipments in multi-echelon stochastic inventory systems imply that locations at the same echelon of a supply chain share inventories in some way, in order to deal with local uncertainties in demands. While the structure of a transshipment policy will depend on many important factors, a commonly observed phenomenon at the retail level, called "customer switching", may be of some significance. Under such a phenomenon, a customer, who cannot obtain a desired product at a specific location, may visit one or more other retail locations in search of the item. We consider the inventory replenishment and transshipment decisions in the presence of such stochastic "customer switching" behavior, for two firms which are either under centralized control, or operate independently. The first model adopted in this study considers two retailers that sell the same product to retail customers. After demand is realized, transshipments occur if only one location has insufficient inventory. Under this circumstance, a random fraction of the unfulfilled demand from the stocked out firm (which we refer to as the "shortage firm") may switch to the other firm with surplus inventory (which we refer to as the "surplus firm"). We examine the impact of such customer switching behavior on the firms' inventory decisions. We identify situations when the firm with surplus inventory is willing to (1) transship the entire quantity requested ("complete pooling policy"), (2) transship a portion of the amount requested ("inventory keeping policy"), or (3) transship nothing ("no-shipping policy") to the shortage firm. We demonstrate that a unique pair of optimal order quantities exist if the two firms are centeredly coordinated. When the firms operate independently, we derive a sufficient condition for the existence of a unique equilibrium replenishment order quantity pair. We also explore the optimal shortage or excess reporting policy when inventory information is asymmetric. Since the firm with a surplus makes a transshipment decision based on the magnitude of the shortage at the other location, it is possible that the shortage firm reports to the surplus firm some desired shortage quantity, instead of the real shortage. We prove that there is a possibility that the underreporting situation exists.
Sleep during the maintenance phase of treatment for acute lymphoblastic leukemia
Authors:   , Daniel Lauren , Kloss Jacqueline D. , Barakat Lamia
Published: July 2021

Treatment for acute lymphoblastic leukemia (ALL) continues to increase in effectiveness, making considerations of side-effect profiles of treatment an important focus for improving quality of life. The maintenance phase of ALL treatment lasts for 2 to 3 years and sees children cycling on and off the corticosteroids dexamethasone or prednisone. Corticosteroids have been linked to changes in sleep patterns, mood, and behavior in previous research; though effects of these drugs on quality of life in children with ALL have not been fully described. During the maintenance phase, children may return to school and activities they enjoyed pre-cancer, but if side-effects keep children from fully engaging in these activities, health-related quality of life (QoL) may suffer even more. Sleep is an important and often understudied area of QoL. The current study described sleep patterns of children taking corticosteroids over a 28-day period using a repeated-measures design to compare time on steroids and time off steroids as well as differences between participants taking dexamethasone versus prednisone. Parents of 37 children 3 to 12 years of age diagnosed with ALL and in the maintenance phase of treatment enrolled in the study. Daily sleep diaries and measures of QoL and fatigue were completed by 24 families. Results indicated that children with ALL exhibit more behavioral sleep difficulties and sleep longer at night compared to normative values for healthy peers. Sleep opportunity, total sleep time, and napping varied significantly across the month between steroids. Children taking prednisone slept for a shorter amount of time than children taking dexamethasone, but they napped more frequently, possibly to compensate. Fatigue and QoL were significantly lower during time on steroids compared to time off steroids. QoL during time on steroids was related to sleep disruptions, suggesting that improving sleep, specifically night wakings and sleep quality, could improve QoL. Future research should explore the processes contributing to disrupted sleep in children taking corticosteroids as well as begin to examine the feasibility of brief behavioral interventions for families to address behavioral sleep concerns during steroid bursts.