bluuebunny/crossref_metadata_2025 huggingface dataset:
Letting the Images Speak for Themselves
Authors:   , Sjarif Kyra J. , Awais Yasmine J.
Published: July 2021

Even upon resettlement, survivors of torture from refugee and asylum-seeker backgrounds often experience a range of physical and psychological consequences rooted in both pre- and post-migration factors that can worsen their mental health outcomes. As a result of torture, individuals are alienated from their personhood, sense of dignity, and intrinsic worth as a human being. The purpose of this capstone grant proposal project was to secure funding for the development of an art therapy program at the Philadelphia Partnership for Resilience, a collaborative which provides legal and social services to immigrant, refugee and asylum-seeker survivors of torture in the Greater Philadelphia region. The literature review highlighted the needs and concerns of survivors of torture, outlining the current interventions utilized in the resettlement context and providing support for the implementation of art therapy with this particular population. A letter of inquiry and a grant proposal were written to meet the criteria outlined by the van Ameringen Foundation, to secure partial funding for an art therapy program for survivors of torture. A synthesis of the literature, reflections on clinical work and on the grant writing process were offered, highlighting the importance of developing culturally sensitive and appropriate interventions for survivors of torture that circumvent the need for verbal expression.
Home-Based Music Therapy Assessment for Older Adults
Authors:   , Lai Kokoszka Ginger Chinchieh , Ierardi Florence
Published: July 2021

In recent years, in response to the socio-economic change in our society, there is an increase in the practice of home-based care for older adults in healthcare. As an allied healthcare profession, the field of music therapy also experienced an increase of demands in providing home-based care. While working with home-based older adults, recognizing the role of both professional and informal caregivers is important because these personal caregivers are instrumental in the overall quality of life by performing daily caretaking tasks for the older adults. In order to understand the challenge a home caregiver may face and to meet the needs of older adults, interdisciplinary professionals must conduct comprehensive home-based assessments and share with the interprofessional healthcare team in order to address a wide array of issues. This thesis includes recommendations for an assessment that is culturally sensitive and includes caregivers, while seeking information about the care recipient's physical, cognitive, functional, and behavioral strengths and needs. Music therapists must approach and document the home-based assessment in a way that not only communicates clinically-relevant findings in written descriptions, but also contributes information that is aligned with the common goals of other professionals working with the care recipients.
Implications of Between- and Within-Worker Variations in Radiation Exposure on Compliance at the Hope Creek Nuclear Generating Station
Authors:   , McNamara Kathryn , Burstyn Igor
Published: July 2021

Objectives: To compare estimated annual doses from the Hope Creek Nuclear Generating Station with industry standards for radiation exposure, while accounting for between- and within-worker variability of monthly doses measurements, and to project compliance with limits on annual dose. Methods: Personal dosimeter data from Hope Creek Nuclear Generating Station was obtained for the period of January - December 2014, comprising 5,388 monthly dose measurements from 888 workers. 27% of measurements were below the limit of detection of 0.1 millirem (mrem). Compliance with the Nuclear Regulatory Commission's annual Occupational Exposure Limit (OEL) of 5,000 mrem was evaluated using three methods. First, a compliance estimate was calculated for the probability of any random worker exceeding the OEL. Second, the probability of overexposure on a monthly basis using 1/12 OEL and the plant's internal limit of 2,000 mrem was calculated for each group according to Rappaport et al (1994). To do so, we had to account for left censored data below the limit of detection using maximum likelihood estimation method of Jin et al (2010). Third, to account for truly unexposed months within a year for a worker, bootstrapped estimates of annual dose were computed; as part of this procedure, we also imputed non-detects based on the maximum likelihood estimates of mean and variances. We also compared projected doses with data for the industry as the whole, obtained from the Nuclear Regulatory Commission's Radiation Exposure Information and Reporting System (REIRS) and the Department of Energy's Radiation Exposure Monitoring System. Results: Using the compliance test, none of the workers exceeded the OEL. After considering between- and within-worker variances, 5 out of 14 groups had a >1% chance of exceeding the 1/12 OEL on a monthly basis. However, external contractors, maintenance, and radiation protection occupational titles had a greater than 5% chance of exceeding the lower internal limit on the monthly basis. Bootstrapped annual exposure doses revealed similar patterns, with very small chances of exceeding the OEL, but great potential for variability. Some workers may reach the 2,000 mrem internal limit if exposed at the 98th percentile of their projected annual dose. However, this scenario is unlikely given the presence of internal plant monitoring systems. Hope Creek is below the national average for boiling water nuclear reactors for total worker dose for 2013. Conclusions: Hope Creek Nuclear Generating Station appears to be typical of its industry peers in terms of annual ionizing radiation doses. Some variations exist in between- and within-worker exposure that are not captured in an aggregated annual dose estimate. These individual and occupational title-level variations are important to take into account when forecasting likelihood of exceeding OEL and suggesting preventative measures.
Evaluation of Printable Sepsis Patient Education Material for Usability and Actionability
Authors:   , Schorr Christa , Zuzelo Patti Rager
Published: July 2021

Sepsis is common, costly, and is a leading cause of death worldwide. During the past decade, quality improvement efforts in sepsis management have led to increased survival. Many sepsis survivors experience sequelae that contribute to unplanned hospital readmission associated with poor outcomes. Despite ongoing efforts to improve sepsis patient care, methods for reducing sepsis readmissions is limited. Additionally, public and patient knowledge regarding sepsis is lacking. Improving sepsis patient outcomes requires early diagnosis and treatment. Increasing patient and caregiver knowledge of sepsis and when to seek medical care is essential, particularly for patients at risk for readmission. No current standards exist regarding effective methods or tools to provide sepsis patient/caregiver discharge education. An evaluation of an available sepsis education tool using a validated measure to assess printable patient education material for understandability and actionability was conducted. An electronic survey was completed by nine national sepsis content experts, with a 90% response rate. Mean usability and actionability scores were above 80% with fair to moderate agreement across 24 survey items. Areas for improvement include providing a summary, modification of images and simplifying language. Results from this project may be useful for future sepsis patient education material.
A case study of an instrumental music program and its influence on the culture of a school
Authors:   , Womack Anthony Terence , Smith Brian K. , Grant Allen C.
Published: July 2021

The purpose of this case study was to examine how participation in a school-based instrumental music program contributed to the culture of a suburban high school. The questions guiding the research were: (1) How and why are multiple music programs supported by staff, students, parents and the community at this school? (2) What are the benefits of maintaining a music curriculum at the school? A single-site case study was conducted at Bigrock High School, a suburban public school in an area outside a major Mid-Atlantic city. The case study utilized in-depth interviews of students, parents, teachers, school administrator and members of the community as data sources. A content analysis of these interviews provided insight into perceptions and beliefs that stakeholders have about the value of students performing in musical ensembles at this research site. Three strands of literature helped frame the content analysis, namely self-efficacy, social capital, and the implementation of music schools. Findings from this study can provide useful ideas on how schools with fewer resources can benefit from having a music program at their site. This includes investigating programs that support the arts in and outside of schools. Future research can focus on schools with smaller music programs and investigate ideas on becoming larger. Additionally, future research can be centered on the level of musical influence to children whose parents/guardians also played a musical instrument.
Immersive Media in Museums and Museum Education
Authors:   , Knise Felicia A. , Brody Jean , Vakharia Neville
Published: July 2021

This thesis explores the use of immersive media, specifically augmented and virtual reality (AR and VR), as an educational tool in the museum space. My findings show that there are great limitations and benefits to implementing immersive media into a museum exhibit, but if done properly can be very rewarding for visitors. AR and VR can create memorable experiences for visitors in a time where attendance is declining in the arts. Technology can also increase time on task and enhance learning for visitors. These types of technologies have developed extensively in the past few years, to the extent that it is now time for museums to start using the technologies to enhance learning in their exhibits.
Project Plié
Authors:   , Hickman Ayako , Brody Jean
Published: July 2021

Moving from Japan, a country with relative homogeneity in its population, I admire the rich ethnic and racial diversity present in America and how it adds so much vibrancy to the culture and art we experience. And it is something I cherish as a former ballet trainee and newly naturalized citizen. However, I discovered that the lack of diversity in ballet is one of the most talked about subjects in the field of dance today. What are ballet companies doing today to close this diversity gap? I chose to investigate the state of diversity in ballet through a case study of Project Plié, a diversity initiative led by the American Ballet Theatre since 2013. I conducted an in-depth interview with two of the Education and Training staff of the American Ballet Theatre. In addition, I conducted interviews with Project Plié's partner organizations, including Dance Theatre of Lynchburg, BalletMet and the Pittsburgh Ballet Theatre. What I gleaned from the interviews was that there are strong and growing commitments by ballet organizations small and large to push inclusive practices, where their communities and funding organizations are also increasingly interested. Nonetheless, pre-professional ballet training of a high caliber is not always accessible to minority populations due to the many barriers that cannot be transformed by any one organization; Project Plié's vision transcends institutional boundaries and its leadership to rally communities nationwide, therefore gives tremendous hope to its partner organizations and to the dance field.
Experiences of Biographical Disruption Among Young Adult Cancer Survivors
Authors:   , Gallagher Erin A. , Goodill Sherry W.
Published: July 2021

Young adulthood is a time of transition in which individuals gain independence from caregivers, form intimate relationships, strengthen bonds with peers, and seek to further educational and career goals. Individuals who receive a cancer diagnosis in young adulthood face unique challenges related to attaining these goals. Recent research suggests that young adult cancer survivors perceive their lives as being biographically disrupted by cancer. The objective of the present study was to describe the subjective, embodied experiences of biographical disruption, including diagnosis, treatment, and survivorship, of cancer in young adults. Three participants who identified as survivors of cancer in young adulthood engaged in a movement elicitation process followed by verbal interviews. Phenomenological research methods were used to discover themes related to their embodied experiences of biographical disruption. Nine themes were identified through data analysis. The first seven themes are organized around participants' sense of dynamic embodiment throughout specific phases of the cancer experience: Embodying the Routine Path before Cancer, Unpredictability and Disbelief in the Body in Diagnosis, Dynamic Shifts in Embodied Coping and Perceptions of the Body during Treatment, Processing the Cancer Experience after Treatment Delays Forward Movement, Re-Embodiment Leads to Negotiating Pre- and Post-Cancer Identity in Early Survivorship, Understanding and Adapting to the New Normal Body in the Present, and Embodied Self- Care in Survivorship. The final two themes were identified as being central to the global experience of cancer in young adulthood: Biographical Disruption in Young Adulthood Represents Lost or Distorted Time and Embodied Biographical Disruption Manifests as Social Disruption. Results from this study are discussed in relation to their implications for future research and dance/movement therapy practice.
Caregiver Involvement in Discharge Planning of Older Hospitalized Patients to Reduce Readmissions
Authors:   , Laumer Debra L. , Zuzelo Patti Rager
Published: July 2021

Background: Involving caregivers of older patients in discharge planning has been shown to reduce hospital readmissions by 25% at 90 days and 24% at 180 days. Purpose: To align expectations of patient caregivers with the care delivery provided during discharge planning by hospital personnel in accordance with the requirements of the CARE Act. Method: Two surveys were conducted, one provided to hospital personnel and the other to lay caregivers, to determine perceptions about caregiver involvement in discharge planning. Evaluation: Using a SOAR Analysis, five strengths and six opportunities were identified, and aspirations and desired results proposed. To promote sustainability and continuous quality improvement, a report card to monitor readmissions related to the presence or absence of caregiver involvement in discharge planning was developed. Clinical Implications: As the action plan is implemented and hospital culture changes, the caregiver will be regarded by hospital personnel as an extension of the patient, and caregivers will become more effective in their roles. This should result in greater caregiver involvement in discharge planning and patient advocacy. The report card will enable the monitoring of outcomes over time. Recommendations: To foster a more successful partnership between caregivers and patients as they transition out of the hospital, a recommendation is to ask not only for the patient's consent in naming a caregiver, but also garnering consent of the caregiver as a willing and able partner in care.
What Impact Has the Affordable Care Act Had on Women's Healthcare?
Authors:   , Borlie Erika A. , Rundio Al
Published: July 2021

Background: Inequalities in medical care have been a constant epidemic in the United States of America for several years. Consequently, the Affordable Care Act (ACA), passed in 2010 and was fully implemented in 2014, with the aim to expand healthcare coverage and bring about a new era of healthcare access and decrease these inequalities. The passage of the Affordable Care Act (ACA) initiated the transformation of the United States healthcare system. The ACA fosters a preventative healthcare model that emphasizes primary care, funds community health initiatives, and promotes quality and preventive care. Methods: Through a survey amongst women ages 18-45 in the downtown Philadelphia area, towards a closer look into the effects of the Affordable Care Act on women with systemic analysis. Evaluation: Fifty completed questionnaires were compiled together and the results were analyzed with the SPSS software. A Pearson Correlation was determined for the results. Significance and Implications: With the Affordable Care Act in effect, more women have improved access to care and preventive medicine. The rate of unwanted pregnancies and the ability to detect abnormalities has become a positive outcome.
Automatically Improving Cell Segmentation in Time-Lapse Microscopy Images Using Temporal Context From Tracking and Lineaging
Authors:   , Winter Mark , Cohen Andrew R.
Published: July 2021

Over the past decade biologists and microscopists have produced truly amazing movies, showing in wonderful detail the dynamics of living cells and subcellular structures. Access to this degree of detail in living cells is a key aspect of current biological research. This wealth of data and potential discovery is constrained by a lack of software tools. The standard approach to biological image analysis begins with segmentation to identify individual cells, tracking to maintain cellular identities over time, and lineaging to identify parent-daughter relationships. This thesis presents new algorithms for improving the segmentation, tracking and lineaging of live cell time-lapse microscopy images. A new ''segmentation from lineage'' algorithm feeds lineage or other high-level behavioral information back into segmentation algorithms along with temporal context provided by the multitemporal association tracker to create a powerful iterative learning algorithm that significantly improves segmentation and tracking results. A tree inference algorithm is used to improve automated lineage generation by integrating known cellular behavior constraints as well as fluorescent signals if available. The ''learn from edits'' technique uses tracking information to propagate user corrections to automatically correct further tracking mistakes. Finally, the new pixel replication algorithm is used for accurately partitioning touching cells using elliptical shape models. These algorithms are integrated into the LEVER lineage editing and validation software, providing user interfaces for automated segmentation, tracking and lineaging, as well as the ability to easily correct the automated results. These algorithms, integrated into LEVER, have identified key behavioral differences in embryonic and adult neural stem cells. Edit-based and functional validation techniques are used to evaluate and compare the new algorithms with current state of the art segmentation and tracking approaches. All the software as well as the image data and analysis results are released under a new open source/open data model built around Gitlab and the new CloneView interactive web tool.
Physical Properties of Surface Modified PVDF Fibers and PVDF Template Carbon-Carbon Shish Kebab for Nanocomposites
Authors:   , Connor Angelica Althea , Li Christopher Y.
Published: July 2021

Because of its large range of sizes and its customizability, porous polymer materials have gained interest in many applications including energy storage , tissue engineering, and filtration, and environmental cleanup. One vast subfield of macroporous polymer materials is electrospun fibrous materials which are porous membranes made of a network of nano- to micron-sized fibers. Although there has been reports on using polymer blends to functionalize the fiber surface in order to create highly porous activated carbon fiber, there have been very few reports of activated carbon fibers with highly ordered hierarchical structures with the same control as with comparative polymeric hierarchically ordered microstructures such as the polymer Nano Fiber Shish Kebab (NFSK) structures. For the first time reported, PVDF-PVDF NFSKs were created and the crystalline structure was characterized. These PVDF-PVDF NFSKs were also used as a precursor for carbonization and the successful maintenance of the original NFSK morphology allowed for the creation of the first reported fully carbon NFSK. With future research into precise control of PVDF-PVDF NFSK dimension and this successful procedure of creating a fully carbon highly ordered hierarchical structured NFSK via carbonization can lead to creation of activated carbon materials with highly desirable, finely tuned, meso- and macroporous microstructure for multifunctionality.
Worker-Job Recommendation for Mixed Crowdsourcing Systems
Authors:   , Jarrett Julian , Blake M. Brian
Published: July 2021

Crowdsourcing is used as model to distribute work over the Internet via an open call to anonymous human workers, who opt to take up work offerings sometimes for some small compensation. Increasingly, crowdsourcing systems are integrated into workflows to provide human computation capabilities. These workflows consist of machine-based workers that work harmoniously on different phases of a task with their human counterparts. This body of work addresses workflows where machines and human workers have the capacity to fulfill the requirements for same tasks. To maximize performance through the delegation of work to the most competent worker, this work outlines a collaborative filtering based approach with a bottom up evaluation based on workers' performance history and their inferred skillsets. Within the model, there are several algorithms, formulae and evaluative metrics. The work also introduces the notion of an Open Push-Pull model; a paradigm that maximizes on the services and strengths of the open call model, while seeking to address its weaknesses such as platform lock-in that affects access to jobs and availability of the worker pool. The work outlines the model in terms of a service-oriented architecture (SOA). It provides a supporting conceptual model for the architecture and an operational model that facilitates both human and machine workers. It also defines evaluative metrics for understanding the true capabilities of the worker pool. Techniques presented in this work can be used to expand the potential worker pool to compete for tasks through the incorporation of machine-oriented workers via virtualization and other electronic services, and human workers via existing crowds. Results in this work articulate the flexibility of our approach to support both human and machine workers within a competitive model while supporting tasks spanning multiple domains and problem spaces. It addresses the inefficiencies of current top-down approaches in worker-job recommendation through use of a bottom-up approach which adapts to dynamic and rapidly changing data. The work contrasts the shortcomings of top-down approaches' dependency on professed profiles which can be under-represented, over-represented or falsified in other ways with evaluative metrics that can be used for the individual and collective assessment of workers within a labor pool.
The Role of Fan-Subtitle Groups in the Process of Introducing US Television Programs Into China
Authors:   , Gao Yiwei , Salas Philip W.
Published: July 2021

Television programs as an important cultural carrier have played a significant role in cross-cultural communication between China and the United States. This thesis will first focus on the television products that have been used as a bridge in cross-cultural communication. It will then discuss the different stages of the introduction of US television programs in China, especially the current stage - Fansub groups. This study gathers data through personal interviews and an online survey. The survey was conducted online, through multiple Chinese social media. The researcher used Chinese online questionnaire software "Wenjuan Wang" to collect data and organize the information. The purpose of the study was to explore the influence of Fansub groups on the Chinese television industry and society. This research aims to explore both the status quo of Fansub groups as they exist on the edge of the legitimate business world and the impact of their work as a carrier of cross-cultural communication in Chinese society. Therefore, this study hopes to illuminate the areas where Fansub groups may potentially become a legitimate player in the market.
Clustering of High-Redshift Quasars
Authors:   , Timlin John D. , Richards Gordon T.
Published: July 2021

In this work, we investigate the clustering of faint quasars in the early Universe and use the clustering strength to gain a better understanding of quasar feedback mechanisms and the growth of central supermassive black holes at early times in the history of the Universe. It has long been understood (e.g., Hopkins et al. 2007a) that the clustering of distant quasars can be used as a probe of different feedback models; however, until now, there was no sample of faint, high-redshift quasars with sufficient density to accurately measure the clustering strength. Therefore we conducted a new survey to increase the number density of these objects. Here, we describe the Spitzer -IRAC Equatorial Survey (SpIES) which is a moderately deep, large-area Spitzer survey which was designed to discover faint, high-redshift (2.9 [less than or equal to] z [less than or equal to] 5.1) quasars. SpIES spans ~115 deg^2 in the equatorial "Stripe 82" region of the Sloan Digital Sky Survey (SDSS) and probes to 5-[sigma] depths of 6.13 [mu]-Jy (21.93 AB magnitude) and 5.75 [mu]-Jy (22.0 AB magnitude) at 3.6 and 4.5 microns. At these depths, SpIES is able to observe faint quasars, and we show that SpIES recovers ~ 94% of the high-redshift (z > 3.5), spectroscopically-confirmed quasars that lie within its footprint. SpIES is also ideally located on Stripe 82 for two reasons: It surrounds existing infrared data from the Spitzer-HETDEX Exploratory Large-area (SHELA) survey which increases the area of infrared coverage, and there is a wide range of multi-wavelength, multi-epoch ancillary data on Stripe 82 which we can use together to select high-redshift quasar candidates. To photometrically identify quasar candidates, we combined the optical data from the Sloan Digital Sky Survey and the infrared data from SpIES and SHELA and employed three machine learning algorithms. These algorithms were trained on the optical/infrared colors of known, high-redshift quasars. Using this method, we generate a sample of 1378 objects that are both faint (i > 20.2) and high-redshift (2.9 [less than or equal to] z [less than or equal to] 5.1) which we use to compute the angular two-point correlation function. We fit a single power-law model with an index of delta = 1.39 ± 0.618 and amplitude of theta_0 = 0.71 ± 0.546 arcmin to the correlation function, as well as a dark matter model with a bias of b = 6.78 ± 1.79. The bias in our investigation suggests a model of quasar feedback that considers quasar activity as an intermittent phase in galaxy evolution. If this model is correct, quasar feedback is strong enough to periodically halt the accretion of gas onto the central supermassive black hole of the quasar, which shuts down quasar activity and causes the black hole to stop growing, however it is not strong enough to completely shut down the quasar in the early Universe.
Development Towards a Clinically Relevant Gemcitabine Loaded Ultrasound Contrast Agent
Authors:   , Brown David Karl , Shieh Adrian C.
Published: July 2021

Injectable ultrasound contrast agents (UCAs) are being researched as a vehicle for ultrasound sensitive targeted drug delivery. Chemotherapeutic drugs such as gemcitabine (GEM) can be loaded into the poly(lactic acid) (PLA) shell of an echogenic microbubble (MB) limiting side effects from undesired interactions with GEM and healthy tissue. Upon insonation, GEM-loaded MBs (GEM-MBs) shatter into drug-loaded nanoshards (Nsh) which can pass through the leaky vasculature of the tumor. Pancreatic cancer is known for displaying a dense fibrous stroma surrounding the tumor inhibiting perfusion of chemotherapeutic treatment. Increasing GEM concentration through GEM-MBs may overcome this limitation. Acoustic properties of GEM-MBs were characterized by maximum enhancement and stability under ultrasound (0.45MPa). GEM-MBs reached a maximum enhancement of 18.40±1.78 dB with a half-life of 9.89±3.76 minutes. This confirms that GEM-MBs can successfully reflect ultrasound and is stable enough to travel through the circulatory system. In vitro, cytotoxicity of GEM-MBs and GEM-loaded nanoshards (GEM-Nsh) was observed against MIA PaCa-2 human pancreatic cancer cells and compared to controls daily for 7 days. While unloaded MBs possess no effect on cell growth, GEM-MBs killed cells similar to free GEM at a GEM concentration of 750nM. After 7 days, cells treated with control media, free GEM and GEM-MBs exhibited dsDNA concentrations of 419.63±204.98 ng/mL, 9.92±3.73 ng/mL and 17.89±11.82 ng/mL confirming cytotoxic effects of GEM-MBs in vitro; however, literature suggests that in vitro success does not predict in vivo cytotoxicity. To increase GEM loading, incorporating GEM-bound gold nanoparticles (AuNPs) (GEM-AuNPs) into the MBs was explored. Four methods of synthesizing GEM-AuNPs were compared for size and aggregation. GEM-loading for the final AuNP protocol was found to be 155.77±89.95 [mu]gGEM/mgAuNP on average. These GEM-AuNPs were loaded into polymer MBs at a concentration of 1mg per 0.1g PLA to create GEM-loaded GEM-AuNP-loaded MBs (GEM-AuNP MBs). These MBs were characterized acoustically for maximum enhancement (17.33±2 dB) and half-life (>15 minutes) under constant insonation at 0.42MPa. Compared to GEM-MBs, GEM-AuNPs display similar enhancement with increased stability. GEM-AuNP MBs were found to load significantly more GEM per mg MB than GEM-MBs with 5.51±1.38 [mu]gGEM/mgMB compared to 4.29±0.33 [mu]gGEM/mgMB (p=0.03). Increasing GEM concentration may allow treatment to better penetrate pancreatic stroma and induce a stronger cytotoxic response.
Bone growth strategies and skeletochronological age estimates of desert tortoise (Gopherus agassizii) populations
Authors:   , Curtin Amanda Jane , Spotila James Robert
Published: July 2021

Turtles are among the longest- lived vertebrates and concepts related to aging are important because they may have a substantial impact on life history evolution. Age at sexual maturity and longevity are essential baseline data which all demographic studies need for the conservation of extant species. The desert tortoise (Gopherus agassizii) is a threatened species and seems to be long- lived, although population longevity is mostly unknown. Skeletal growth layers can be used to estimate age, and skeletochronology has been shown to accurately age many reptiles. My main objective was to determine whether bone, obtained from carcasses, could be used to indicate differences in longevity and growth strategies among wild desert tortoise populations. I used two skeletochronological methods (the Correction Factor and Ranking Protocol) to estimate ages for tortoises from the Mojave and Sonoran Deserts. Using a sample of 9 knownaged tortoises from Rock Valley, Nevada, I determined that the Correction Factor method provided the most accurate age estimates for juveniles, whereas the Ranking Protocol provided the most accurate age estimates for adults. West Mojave tortoises had the smallest females, highest growth rates, youngest age at sexual maturity but shortest longevity of the three populations. In contrast, Sonoran tortoises had the largest females, lowest growth rates, oldest age at sexual maturity and greatest longevity. East Mojave tortoises showed intermediate traits. Annual growth rates in West Mojave adults were similar to those of juveniles, whereas East Mojave, and especially Sonoran adults had significantly reduced growth rates after the attainment of sexual maturity. West Mojave tortoises may have higher overall growth because of the higher desert productivity and more abundant forage after wet years. The cost for Mojave Desert tortoises (especially western populations ), without dependable and predictable annual forage and water for health and growth maintenance, may be higher mortality and reduced life expectancy, which females have compensated for by evolving a younger age at sexual maturity. Desert tortoises are potential models for the consequences of increased desertification on desert fauna, especially in species that have not evolved as desert specialists but rather have learned to adapt to these extreme environments.
PEG-based degradable networks for drug delivery applications
Authors:   , Ostroha Jamie Lyn , Lowman Anthony M. , Dan Nily
Published: July 2021

The controlled delivery of therapeutic agents by biodegradable hydrogels has become a popular mechanism for drug administration in recent years. Hydrogels are threedimensional networks of polymer chains held together by crosslinks. Although the changes which the hydrogel undergoes in solution are important to a wide range of experimental studies, they have not been investigated systematically and the factors which influence the degree of swelling have not been adequately described. Hydrogels made of poly(ethylene glycol) (PEG) will generally resist degradation in aqueous conditions, while a hydrogel made from a copolymer of poly(lactic acid) (PLA) and PEG will degrade via hydrolysis of the lactic acid group. This ability to degrade makes these hydrogels promising candidates for controlled release drug delivery systems. The goal of this research was to characterize the swelling and degradation of both degradable and non-degradable gels and to evaluate the release of different drugs from these hydrogels, where the key variable is the molecular weight of the PEG segment. These hydrogels were formed by the addition and subsequent chemically crosslinking of methacrylate end groups. During crosslinking, both PEG and LA-PEG-LA hydrogels of varied PEG molecular weight were loaded with Vitamin B12, Insulin, Haloperidol, and Dextran. It was shown that increasing PEG molecular weight produces a hydrogel with larger pores, thus increasing water uptake and degradation rate. While many environmental factors do not affect the swelling behavior, they do significantly impact the degradation of the hydrogel, and thus the release of incorporated therapeutic agents.
Nanoporous carbons derived from binary carbides and their optimization for hydrogen storage
Authors:   , Dash Ranjan Kumar , Gogotsi Yury
Published: July 2021

On-board hydrogen storage is one of the major hurdles for success of hydrogen economy. Hydrogen storage using physisorption technique demands highly porous materials. Carbide derived carbons (CDC), a new class of porous carbons produced by thermo chemical etching of metal atoms from carbides were selected as a method for producing highly porous material for hydrogen storage. In order to synthesize tunable nanoporous carbon and to establish a structure-property relation between initial metal carbide and resultant nanoporous carbon, CDCs were synthesized from four metal carbides, two that have uniform carbon to carbon distance in the lattice structure (ZrC, TiC and SiC) and one that has a non-uniform carbon distribution in the lattice (B4C). It was shown that a uniform distribution of carbon atoms in the carbide is important for obtaining a narrow pore size distribution (PSD). CDC derived from B4C had a relatively broad PSD and contained mesopores even at the lowest synthesis temperature, while the CDC produced from SiC maintained a narrow PSD even at the synthesis temperature of 1200oC. CDC produced from ZrC and TiC has a narrow PSD at low synthesis temperature and pores gets wider at higher temperatures. Comparison of CDCs produced from ZrC, TiC and B4C shows that CDCs produced from ZrC and TiC show a lower degree of ordering than that from B4C at high temperatures. Unlike CDCs produced from ZrC and TiC, the PSD of CDCs from B4C does not change appreciably in the 600-1200oC range. CDCs produced from ZrC and TiC can have both narrowly distributed micropores (pores smaller than 2 nm) and mesopores (pores larger than 2 nm), depending on synthesis temperature. In this work, it is demonstrated that porosity of CDC can be fine tuned with a high accuracy by using different starting carbides and varying the synthesis temperatures. This is very important in many applications of porous carbon, especially for gas storage. CDC from ZrC, TiC, B4C and SiC resulted in a family of high surface area nanoporous carbons (300 to 2300 m2/g) of average pore size ranging from 0.5 to 1.4 nm, A systematic study on hydrogen storage capacity of CDCs and comparison with other materials including metal organic framework (MOF-5), single (SWCNT) and multiwalled carbon nanotubes (MWCNT) dispelled the popular myth that hydrogen physisorption is directly proportional to SSA, and provided guidance for optimal design by showing that a large volume of small open pores is the key to high hydrogen uptake at cryogenic temperatures and ambient pressure. Values up to 3 wt.% and 30 kg/m3 have been demonstrated in CDCs; these are twice what can be stored in MOF-5 and several times higher than has been achieved in SWCNT or MWCNT at 77 K and atmospheric pressure. The isosteric heat of hydrogen adsorption up to 11 kJ/mole of CDCs is higher than that reported for activated carbon, CNT and MOF.
Structure, characterization and exploration of synthesis of conical and polyhedral crystals of graphite
Authors:   , Dimovski Svetlana , Gogotsi Yury
Published: July 2021

The present study describes the structure, Raman spectra and growth model of synthetic and naturally occurring conical and polyhedral nano- and micro- crystals of graphite. While planar graphite and carbon nanotubes have been extensively studied, and their structure and properties are well documented in the literature, the world of nonplanar multishell graphitic materials was somewhat neglected. With a growing tendency to design and utilize materials that will bridge the gap between traditional micro- and "emerging" nano- technologies, the importance of understanding such structures is continuously increasing. In the present work, Raman spectroscopy, scanning and transmission electron microscopy with electron diffraction were used as primary techniques to characterize the morphology and structure of conical and polyhedral nano- and micro- crystals of graphite. Such information was used to understand the environment suitable for their growth. Graphitic carbon cones (GCCs) and graphite polyhedral crystals (GPCs) have an elongated needle-like and, typically, axially symmetric morphology. The length of these low-symmetry crystals ranges from several tens of nanometers up to several microns. Graphite has been known to form seamless graphite nano- and micro-cones that can have up to five different apex angles determined by disclinations in graphite. Scrolled conical structures, which grow with a different mechanism, may have virtually any apex angle between 2-3 degrees up to 150 degrees. However, the "magic" angles of 19.2, 38.9, 60.0, 83.6 and 112.9 degrees are still most frequently observed. These apex angles are found to be energetically preferred as they allow the registry between graphene sheets in the cone. Polygonization of nanotubes accompanied by growth in the radial direction leads to the formation of graphite polyhedral crystals (GPC). They have nanotube cores and graphite crystal faces and remarkably unusual axial symmetries. The structure of carbon cones and polyhedral crystals has been studied, and the mechanism of their formation has been proposed in the present work. The study reports formation of small apex angle cones that have not been predicted by theory, and it also provides detailed information about the occurrence of carbon cones in nature. The morphology, structure and diffraction patterns of graphite polyhedral crystals were explained.
Developmental changes in attention performance and their relationship to behavior and school problems
Authors:   , Fahey Jeanette Chandlee , Williams J. Michael
Published: July 2021

Assessing children's attention capacities over time and in relationship to broader functioning may provide information about the contribution of emergent attention difficulties to later generalized problems with behavior and learning. The purpose of this study was to describe the developmental progression of attention and executive functions in early school-aged children, and to determine the extent to which performance on attention and executive tasks relates to social and biological variables as well as to ecologically meaningful outcomes, such as parent and teacher ratings of behavior and school problems. The 90 participants were selected from a longitudinal clinical trial of children with low to moderate levels of lead exposure. All participants had completed the attention/executive tasks from the NEPSY at age 5 and 7 years, and had been evaluated for behavior and learning problems by their parent and teacher with the BASC at age 7 years. As hypothesized, children's performance significantly improved on all tasks between age 5 and 7 years, and the rate of change differed across the tasks. Correlation analyses examining the associations between social (i.e., IQ and SES) and biological variables (i.e., gender, age at study entry, pretreatment blood lead level, and treatment status) and changes in task performances were not significant. Results of multiple regression analyses supported the modest validity of the NEPSY tasks in predicting behavior and school problems. Specifically, only performance on Tower, an executive task of planning and self-monitoring, was inversely predictive of parent ratings of behavior problems at home, but not until age 7 years when perhaps these functions are more developed. Poor performance on tasks of sustained and selective auditory attentions both at 5 and 7 years, however, was most predictive of teacher perceptions of behavior and learning problems, which is likely related to increased demands to attend to novel verbal information in the classroom. The finding that these NEPSY tasks demonstrated different predictive relationships with the BASC outcomes suggests that they measure different subcomponents of attention and executive functions. Such results have implications for the use of performance measurements of attention in the early identification of antecedents to broader problem outcomes.
Synthesis and characterization of solid solutions of M_(N+1)AX_N phases
Authors:   , Ganguly Adrish , Barsoum Michel W.
Published: July 2021

The MAX phases, best described as polycrystalline nanolaminates, deserve attention in today's world because they combine some of the best properties of ceramics and metals. While considerable work exists on selective MAX phases, to date, little is known about MAX solid solutions. This work is focused on the synthesis and characterization of A- or X-site substituted MAX solid solutions. In general, substitutions on the A sites led, either to solid solution softening or to a monotonic change in properties from one end member to the other. The Vickers microhardness values of the solid solution compositions were in between those of the end members, indicating that no hardening is operative in these systems. Substitutions on the A-sites resulted in a reduction in the residual resistivity ratios and the phonon conductivities as compared to the end members, indicating that solid solution scattering of both phonons and electrons was occurring. Substitutions on the X sites, on the other hand, resulted in an increase in the elastic moduli and a concomitant reduction in the coefficients of thermal expansion with respect to the end members. This behavior, combined with the higher values of Vickers microhardness clearly indicated solid solution hardening. Somewhat surprisingly, the phonon conductivities of Ti₃Al(C_[0.5]N_[0.5])₂ and Ti₂AlC_[0.5]N_[0.5] were higher than the respective end members. This enhancement was attributed to the stiffening of the structure as reflected in the higher shear moduli than that of the end members. All the MAX phases tested herein were kinking nonlinear elastic solids. Substitutions on the X-sites significantly influenced the nonlinear kinking behavior under compression. The threshold stress ([sigma]c) required for kinking and the critical resolved shear stresses needed for dislocations to glide along the basal planes were observed to increase considerably for the solid solutions compared to the end members. The effects of substitutions on the A-sites on the kinking behavior were quite mild relative to those of the X-site substitutions.
Attentional demands and recall of interpersonal information in social anxiety disorder
Authors:   , Greenberg Saluck Robyn S. , Herbert James D.
Published: July 2021

People with social anxiety disorder (SAD) have been shown to have an attentional bias toward anxiety-related cognitions and physical symptoms. If disproportionate attention is directed towards these stimuli, a decreased ability to focus on interpersonal information may result. The ability to follow a conversation so that one can respond appropriately, and the ability to remember details at a later time such as during another discussion with that same person, is an important social skill. With excessive threat-focused attention, a person may not be able to attend to the details of a social interaction, and therefore will not recall them later. Such impaired attention may additionally increase anxiety in a socially anxious person, and according to cognitive theory, may then serve to increase further negative cognitions and anxious symptomatology. This research examined the ability of people with SAD to recall details of an interpersonal interaction, both pertinent and incidental, after engaging in a social interaction. It was hypothesized that persons with generalized SAD, in comparison to normal controls, would have (a) higher self-focused attention (both state and trait), (b) poorer recall of details than normal controls after participation in a behavioral role play test, and (c) comparable recall after observation of a social interaction. It was also hypothesized that (d) self-focused attention (state and trait) would be related to poorer recall in all participants. Nineteen individuals with SAD and 19 matched controls took part in this study. Results revealed that, relative to non-anxious controls, those with SAD (a) had higher state and trait self-focused attention, (b) did not demonstrate memory deficit for details related to the role play interaction, and (c) had equivalent recall of information when observing a social situation. Furthermore, (d) state self-focused attention was related to and predictive of poorer recall of the interpersonal interaction in participants with SAD, but not in non-anxious controls. Results indicate that although persons with SAD in general are able to remember details from a conversation and about their social partner, those with high self-focused attention specifically were deficient in this area. Clinical implications and recommendations for future research are also discussed.