Worksite health promotion programs in college settings

PubMed Central

Hill-Mey, Patricia E.; Kumpfer, Karol L.; Merrill, Ray M.; Reel, Justine; Hyatt-Neville, Beverly; Richardson, Glenn E.

2015-01-01

The purpose of this paper is to describe the multifaceted nature and benefits of worksite health promotion programs (WHPPs), with emphasis on the college setting. An assessment of the peer-reviewed literature was conducted of articles published since 2000. Several search engines were accessed and selected key words were used. Most studies examining WHPPs have focused on return on investment and productivity. Research that targets the softer side-benefits of health promotion programs in the workplace is less available. Although the college setting offers some advantages for implementing health promotion programs. They may also have unique challenges due to their large and diverse employee population. There is little research to show the effectiveness and unique challenges of college-based health promotion programs. PMID:25861657

Measurement of Emissions from Produced Water Ponds: Upstream Oil and Gas Study #1; Final Report

EPA Science Inventory

Significant uncertainty exists regarding air pollutant emissions from upstream oil and gas production operations. Oil and gas operations present unique and challenging emission testing issues due to the large variety and quantity of potential emissions sources. This report summ...

Endocarditis caused by Rhodotorula infection.

PubMed

Simon, Matthew S; Somersan, Selin; Singh, Harjot K; Hartman, Barry; Wickes, Brian L; Jenkins, Stephen G; Walsh, Thomas J; Schuetz, Audrey N

2014-01-01

Rhodotorula is an emerging opportunistic fungal pathogen that is rarely reported to cause endocarditis. We describe a case involving a patient who developed endocarditis due to Rhodotorula mucilaginosa and Staphylococcus epidermidis, proven by culture and histopathology. The case illustrates the unique diagnostic and therapeutic challenges relevant to Rhodotorula spp.

OBESITY: CHALLENGES TO VENTILATORY CONTROL DURING EXERCISE A BRIEF REVIEW

PubMed Central

Babb, Tony G.

2013-01-01

Obesity is a national health issue in the US. Among the many physiological changes induced by obesity, it also presents a unique challenge to ventilatory control during exercise due to increased metabolic demand of moving larger limbs, increased work of breathing due to extra weight on the chest wall, and changes in breathing mechanics. These challenges to ventilatory control in obesity can be inconspicuous or overt among obese adults but for the most part adaptation of ventilatory control during exercise in obesity appears remarkably unnoticed in the majority of obese people. In this brief review, the changes to ventilatory control required for maintaining normal ventilation during exercise will be examined, especially the interaction between respiratory neural drive and ventilation. Also, gaps in our current knowledge will be discussed. PMID:23707540

Low-Power, Chip-Scale, Carbon Dioxide Gas Sensors for Spacesuit Monitoring

NASA Technical Reports Server (NTRS)

Rani, Asha; Shi, Chen; Thomson, Brian; Debnath, Ratan; Wen, Boamei; Motayed, Abhishek; Chullen, Cinda

2018-01-01

N5 Sensors, Inc. through a Small Business Technology Transfer (STTR) contract award has been developing ultra-small, low-power carbon dioxide (CO2) gas sensors, suited for monitoring CO2 levels inside NASA spacesuits. Due to the unique environmental conditions within the spacesuits, such as high humidity, large temperature swings, and operating pressure swings, measurement of key gases relevant to astronaut's safety and health such as(CO2), is quite challenging. Conventional non-dispersive infrared absorption based CO2 sensors present challenges inside the spacesuits due to size, weight, and power constraints, along with the ability to sense CO2 in a high humidity environment. Unique chip-scale, nanoengineered chemiresistive gas-sensing architecture has been developed for this application, which can be operated in a typical space-suite environmental conditions. Unique design combining the selective adsorption properties of the nanophotocatalytic clusters of metal-oxides and metals, provides selective detection of CO2 in high relative humidity conditions. All electronic design provides a compact and low-power solution, which can be implemented for multipoint detection of CO2 inside the spacesuits. This paper will describe the sensor architecture, development of new photocatalytic material for better sensor response, and advanced structure for better sensitivity and shorter response times.

Indicators used to monitor subsurface oil during the Deepwater Horizon Event

EPA Science Inventory

The Gulf of Mexico Deepwater Horizon oil spill was the largest accidental marine spill in the history of the petroleum industry. The spill was also unprecedented due to the extreme depth of the wellhead leak within the ocean, posing unique challenges to the monitoring efforts, w...

Quality Assurance in Turkish Higher Education

ERIC Educational Resources Information Center

Bugday Ince, Sehriban; Gounko, Tatiana

2014-01-01

The implementation of quality assurance (QA) is one of the most challenging reform areas for Turkey due to the unique organization of its higher education system. This paper explores the development of QA systems in Turkish universities. Using a qualitative case study approach, the authors examine how Turkey accomplishes the goal of implementing…

Career Counseling with Undocumented Latino Youth: A Qualitative Analysis of School Counselors

ERIC Educational Resources Information Center

Storlie, Cassandra Ann

2013-01-01

The career development trajectory of undocumented Latino youth can present unique challenges for school counselors. Undocumented Latino youth have few career choices due to holding different values from the majority culture, realistic fears of deportation, restrictions in obtaining lawful employment, and having an unconventional pathway to…

Methods of Oil Detection in Response to the Deepwater Horizon Oil Spill

EPA Science Inventory

Detecting oil in the northern Gulf of Mexico following the Deepwater Horizon oil spill presented unique challenges due to the spatial and temporal extent of the spill and the subsequent dilution of oil in the environment. Over time, physical, chemical, and biological processes a...

Endocarditis Caused by Rhodotorula Infection

PubMed Central

Simon, Matthew S.; Somersan, Selin; Singh, Harjot K.; Hartman, Barry; Wickes, Brian L.; Jenkins, Stephen G.; Walsh, Thomas J.

2014-01-01

Rhodotorula is an emerging opportunistic fungal pathogen that is rarely reported to cause endocarditis. We describe a case involving a patient who developed endocarditis due to Rhodotorula mucilaginosa and Staphylococcus epidermidis, proven by culture and histopathology. The case illustrates the unique diagnostic and therapeutic challenges relevant to Rhodotorula spp. PMID:24197888

The Virtual Professor: A New Model in Higher Education

ERIC Educational Resources Information Center

Valentine, Randall; Bennett, Robert

2013-01-01

Traditional colleges and universities face a unique challenge of increasing the scope of educational operations to accommodate the growing demand for online education. While online enrollments in higher education have grown at a rapid pace, faculty resources have remained stagnant at many institutions due to budget constraints and a sluggish…

Promoting Character Development through Teaching Wrestling in Physical Education

ERIC Educational Resources Information Center

Destani, Fitni; Hannon, James C.; Podlog, Leslie; Brusseau, Timothy A.

2014-01-01

Character development has become an important component of physical education that contributes directly to the affective learning domain. However, teaching character development can be challenging. The purpose of this article is to suggest that character development be promoted through the teaching of wrestling, due to the unique moral development…

Robust Radio Broadcast Monitoring Using a Multi-Band Spectral Entropy Signature

NASA Astrophysics Data System (ADS)

Camarena-Ibarrola, Antonio; Chávez, Edgar; Tellez, Eric Sadit

Monitoring media broadcast content has deserved a lot of attention lately from both academy and industry due to the technical challenge involved and its economic importance (e.g. in advertising). The problem pose a unique challenge from the pattern recognition point of view because a very high recognition rate is needed under non ideal conditions. The problem consist in comparing a small audio sequence (the commercial ad) with a large audio stream (the broadcast) searching for matches.

Progress and Challenges in Developing Aptamer-Functionalized Targeted Drug Delivery Systems.

PubMed

Jiang, Feng; Liu, Biao; Lu, Jun; Li, Fangfei; Li, Defang; Liang, Chao; Dang, Lei; Liu, Jin; He, Bing; Badshah, Shaikh Atik; Lu, Cheng; He, Xiaojuan; Guo, Baosheng; Zhang, Xiao-Bing; Tan, Weihong; Lu, Aiping; Zhang, Ge

2015-10-09

Aptamers, which can be screened via systematic evolution of ligands by exponential enrichment (SELEX), are superior ligands for molecular recognition due to their high selectivity and affinity. The interest in the use of aptamers as ligands for targeted drug delivery has been increasing due to their unique advantages. Based on their different compositions and preparation methods, aptamer-functionalized targeted drug delivery systems can be divided into two main categories: aptamer-small molecule conjugated systems and aptamer-nanomaterial conjugated systems. In this review, we not only summarize recent progress in aptamer selection and the application of aptamers in these targeted drug delivery systems but also discuss the advantages, challenges and new perspectives associated with these delivery systems.

Obesity: challenges to ventilatory control during exercise--a brief review.

PubMed

Babb, Tony G

2013-11-01

Obesity is a national health issue in the US. Among the many physiological changes induced by obesity, it also presents a unique challenge to ventilatory control during exercise due to increased metabolic demand of moving larger limbs, increased work of breathing due to extra weight on the chest wall, and changes in breathing mechanics. These challenges to ventilatory control in obesity can be inconspicuous or overt among obese adults but for the most part adaptation of ventilatory control during exercise in obesity appears remarkably unnoticed in the majority of obese people. In this brief review, the changes to ventilatory control required for maintaining normal ventilation during exercise will be examined, especially the interaction between respiratory neural drive and ventilation. Also, gaps in our current knowledge will be discussed. Copyright © 2013 Elsevier B.V. All rights reserved.

Conducting Rigorous Survey Research in the Study of School-Based Consultation

ERIC Educational Resources Information Center

Hazel, Cynthia E.; Newman, Daniel S.; Barrett, Courtenay A.

2016-01-01

The evidence base for school-based consultation practice and training is limited by a small number of studies, possibly due to unique challenges in researching consultation. For example, there are myriad variables to measure and idiosyncratic cultural and contextual factors to account for when investigating what works, for whom, and in what…

An Effective Approach to Developing Function-Based Interventions in Early Childhood Classrooms

ERIC Educational Resources Information Center

Wood, Brenna K.; Ferro, Jolenea B.

2014-01-01

Due to the unique features of early childhood classrooms, teachers routinely modify the social and physical environment to support children with mild to moderate challenges. Yet despite their access to behavioral consultants, school-based prekindergarten programs are more likely to expel young children from their classroom settings compared with…

Understanding the Importance of Relationships: Perspective of Children with Intellectual Disabilities, Their Parents, and Nurses in Canada

ERIC Educational Resources Information Center

Aston, Megan; Breau, Lynn; MacLeod, Emily

2014-01-01

Effective and therapeutic relationships between health care providers and clients are important elements for positive health outcomes. Children with intellectual disabilities (IDs) and their parents face unique challenges in establishing relationships with health care providers due to social and institutional stigma and stereotypes associated with…

The Challenges of Teaching Strategic Management: Working toward Successful Inclusion of the Resource-Based View

ERIC Educational Resources Information Center

Schneider, Marguerite; Lieb, Pamela

2004-01-01

The industrial organization economics (IOE) and resource-based view (RBV) schools contribute uniquely to the strategic management curriculum. However, presentation of the RBV is often inadequate or ineffective, in part due to faculty habit, students' conceptualization of knowledge as objective and readily transferable, and course pedagogy. We…

Developing an Effective Instrument for Assessing the Performance of Public University Presidents

ERIC Educational Resources Information Center

Lester, Dennis

2010-01-01

Conducting a worthwhile assessment of the performance of senior leaders such as university presidents poses unique challenges for public institutions of higher education. One of the most difficult issues is determining the "content" and "format" of the assessment instrument. Due to the breadth and complexity of the job, the…

Quality, Safety and Patient Centered Care--A Dream Come True in the Mountains of Northern Pakistan. An Award winning project of "2015 Quality, Safety & Patient Centered Care Award" at, Chicago USA.

PubMed

Jassani, Kashif; Essani, Rozina Roshan; Abbas, Syed Nadeem Husain

2016-01-01

Northern Pakistan remains very challenging terrain due to harsh weather all year round presenting an infrastructura, human resource and supply chain challenge of its own. Many times the facility had to move to different locations on emergency and ad hoc basis due to landslides, earthquakes affecting continuity of care. Providing quality healthcare to often resource constraint hard-to-reach areas has always been AKHS,P's unique forte. Breaking barriers for catchment population to access quality healthcare, AKHS,P embarked on an initiative of implementing, achieving and sustaining ISO 9001:2008 Quality Management System international standards certification. This article shares the unique experience of AKHS,P in achieving and sustaining ISO 9001:2008 International Quality Management System Certification. After untiring efforts and the hard work of ground staff; AKHS,P achieved ISO 9001:2008 International Quality Management System Certification as well as 1st Surveillance Audit which itself proved that AKHS,P sustained quality systems and ensured continuous quality improvement in the Mountains of Northern Pakistan.

Global surgery for pediatric hydrocephalus in the developing world: a review of the history, challenges, and future directions.

PubMed

Muir, Ryan T; Wang, Shelly; Warf, Benjamin C

2016-11-01

OBJECTIVE Pediatric hydrocephalus is one of the most common neurosurgical conditions and is a major contributor to the global burden of surgically treatable diseases. Significant health disparities exist for the treatment of hydrocephalus in developing nations due to a combination of medical, environmental, and socioeconomic factors. This review aims to provide the international neurosurgery community with an overview of the current challenges and future directions of neurosurgical care for children with hydrocephalus in low-income countries. METHODS The authors conducted a literature review around the topic of pediatric hydrocephalus in the context of global surgery, the unique challenges to creating access to care in low-income countries, and current international efforts to address the problem. RESULTS Developing countries face the greatest burden of pediatric hydrocephalus due to high birth rates and greater risk of neonatal infections. This burden is related to more general global health challenges, including malnutrition, infectious diseases, maternal and perinatal risk factors, and education gaps. Unique challenges pertaining to the treatment of hydrocephalus in the developing world include a preponderance of postinfectious hydrocephalus, limited resources, and restricted access to neurosurgical care. In the 21st century, several organizations have established programs that provide hydrocephalus treatment and neurosurgical training in Africa, Central and South America, Haiti, and Southeast Asia. These international efforts have employed various models to achieve the goals of providing safe, sustainable, and cost-effective treatment. CONCLUSIONS Broader commitment from the pediatric neurosurgery community, increased funding, public education, surgeon training, and ongoing surgical innovation will be needed to meaningfully address the global burden of untreated hydrocephalus.

Caring for Refugee Youth in the School Setting.

PubMed

Johnson, Jennifer Leigh; Beard, Joyce; Evans, Dena

2017-03-01

Annually, over 80,000 refugees enter the United States as a result of political or religious persecution. Of these, approximately 35% to 40% are children and adolescents. Refugees are faced with challenges associated with living conditions, cultural and social norms, and socioeconomic status due to problems occurring in their homelands. These challenges include but are not limited to malnutrition, communicable disease, questionable immunization status, lack of formal education, sexual abuse, violence, torture, human trafficking, homelessness, poverty, and a lack of access to health care. Moreover, the psychological impact of relocation and the stress of acculturation may perpetuate many of these existing challenges, particularly for refugee youth, with limited or underdeveloped coping skills. School nurses are uniquely poised to support refugee youth in the transition process, improve overall health, and facilitate access to primary health services. The purpose of this article is to provide an overview of the unique refugee experience, examine the key health care needs of the population, and present school nurses with timely and relevant resources to assist in caring for refugee youth.

Advanced Stirling Radioisotope Generator Life Certification Plan

NASA Technical Reports Server (NTRS)

Rusick, Jeffrey J.; Zampino, Edward J.

2013-01-01

An Advanced Stirling Radioisotope Generator (ASRG) power supply is being developed by the Department of Energy (DOE) in partnership with NASA for potential future deep space science missions. Unlike previous radioisotope power supplies for space exploration, such as the passive MMRTG used recently on the Mars Curiosity rover, the ASRG is an active dynamic power supply with moving Stirling engine mechanical components. Due to the long life requirement of 17 years and the dynamic nature of the Stirling engine, the ASRG project faced some unique challenges trying to establish full confidence that the power supply will function reliably over the mission life. These unique challenges resulted in the development of an overall life certification plan that emphasizes long-term Stirling engine test and inspection when analysis is not practical. The ASRG life certification plan developed is described.

Applications of “Tender” Energy (1-5 keV) X-ray Absorption Spectroscopy in Life Sciences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Northrup, Paul; Leri, Alessandra; Tappero, Ryan

The “tender” energy range of 1 to 5 keV, between the energy ranges of most “hard” (>5 keV) and “soft” (<1 keV) synchrotron X-ray facilities, offers some unique opportunities for synchrotron-based X-ray absorption fine structure spectroscopy in life sciences. In particular the K absorption edges of Na through Ca offer opportunities to study local structure, speciation, and chemistry of many important biological compounds, structures and processes. This is an area of largely untapped science, in part due to a scarcity of optimized facilities. Such measurements also entail unique experimental challenges. Lastly, this brief review describes the technique, its experimental challenges,more » recent progress in development of microbeam measurement capabilities, and several highlights illustrating applications in life sciences.« less

Intensity-invariant coding in the auditory system.

PubMed

Barbour, Dennis L

2011-11-01

The auditory system faithfully represents sufficient details from sound sources such that downstream cognitive processes are capable of acting upon this information effectively even in the face of signal uncertainty, degradation or interference. This robust sound source representation leads to an invariance in perception vital for animals to interact effectively with their environment. Due to unique nonlinearities in the cochlea, sound representations early in the auditory system exhibit a large amount of variability as a function of stimulus intensity. In other words, changes in stimulus intensity, such as for sound sources at differing distances, create a unique challenge for the auditory system to encode sounds invariantly across the intensity dimension. This challenge and some strategies available to sensory systems to eliminate intensity as an encoding variable are discussed, with a special emphasis upon sound encoding. Copyright © 2011 Elsevier Ltd. All rights reserved.

Applications of “Tender” Energy (1-5 keV) X-ray Absorption Spectroscopy in Life Sciences

DOE PAGES

Northrup, Paul; Leri, Alessandra; Tappero, Ryan

2016-02-15

The “tender” energy range of 1 to 5 keV, between the energy ranges of most “hard” (>5 keV) and “soft” (<1 keV) synchrotron X-ray facilities, offers some unique opportunities for synchrotron-based X-ray absorption fine structure spectroscopy in life sciences. In particular the K absorption edges of Na through Ca offer opportunities to study local structure, speciation, and chemistry of many important biological compounds, structures and processes. This is an area of largely untapped science, in part due to a scarcity of optimized facilities. Such measurements also entail unique experimental challenges. Lastly, this brief review describes the technique, its experimental challenges,more » recent progress in development of microbeam measurement capabilities, and several highlights illustrating applications in life sciences.« less

Issues with RNA-seq analysis in non-model organisms: A salmonid example.

PubMed

Sundaram, Arvind; Tengs, Torstein; Grimholt, Unni

2017-10-01

High throughput sequencing (HTS) is useful for many purposes as exemplified by the other topics included in this special issue. The purpose of this paper is to look into the unique challenges of using this technology in non-model organisms where resources such as genomes, functional genome annotations or genome complexity provide obstacles not met in model organisms. To describe these challenges, we narrow our scope to RNA sequencing used to study differential gene expression in response to pathogen challenge. As a demonstration species we chose Atlantic salmon, which has a sequenced genome with poor annotation and an added complexity due to many duplicated genes. We find that our RNA-seq analysis pipeline deciphers between duplicates despite high sequence identity. However, annotation issues provide problems in linking differentially expressed genes to pathways. Also, comparing results between approaches and species are complicated due to lack of standardized annotation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Performance of Geneva® apple rootstock selections with ‘Brookfield Gala’ and ‘Cripps Pink’ on a tall spindle system

USDA-ARS?s Scientific Manuscript database

High density orchard systems have become the standard for new plantings in many apple production regions due to their earlier yield and higher cumulative yields which results in greater return on investments. Growers in the Mid-Atlantic region have unique challenges compared to northern production r...

Make Task Constraints Work for You: Teaching Object-Control Skills to Students with Autism Spectrum Disorder

ERIC Educational Resources Information Center

Colombo-Dougovito, Andrew M.; Block, Martin

2016-01-01

Teaching object-control skills to students with autism spectrum disorder (ASD) can be difficult due to the unique challenges posed by the individual; however, it is necessary for the students' future success and ability to perform physical activities. Utilizing concepts from dynamic systems theory and Newell's constraint approach, object-control…

Valuing morbidity from wildfire smoke exposure: A comparison of revealed and stated preference techniques

Treesearch

Leslie Richardson; John B. Loomis; Patricia A. Champ

2013-01-01

Estimating the economic benefits of reduced health damages due to improvements in environmental quality continues to challenge economists. We review welfare measures associated with reduced wildfire smoke exposure, and a unique dataset from California's Station Fire of 2009 allows for a comparison of cost of illness (COI) estimates with willingness to pay (WTP)...

Challenges of managing disease in tall orchard trees – pecan scab, a case study

USDA-ARS?s Scientific Manuscript database

Managing disease in tall orchard trees presents unique issues not found in relatively shorter horticultural and agronomic crops, simply due to height. Pecan scab (caused by Fusicladium effusum [G. Winter] Seyran et al.) is used as an example of a major disease of one of the tallest orchard crops in ...

Managing Educational Reforms during Times of Transition: The Role of Leadership

ERIC Educational Resources Information Center

Moccia, Salvatore

2016-01-01

Being the leader of a university is a unique and diverse challenge ever since universities have been described by Cohen and Marchin (1974) as "organized anarchies" with high inertia, unclear technologies and problematic goals. This could be in part due to the fact of the temporary status of their roles amplifying a sort of conflict of…

Developing a Student Respite Provider System for Children with Autism

ERIC Educational Resources Information Center

Openden, Daniel; Symon, Jennifer B.; Koegel, Lynn Kern; Koegel, Robert L.

2006-01-01

Many parents of children with autism and other severe disabilities report heightened levels of stress due to the unique challenges their children present. Respite care is likely to alleviate some of the stress associated with caring for a child with a severe disability. However, it is often difficult for families to identify motivated and…

Progress and Challenges in Developing Aptamer-Functionalized Targeted Drug Delivery Systems

PubMed Central

Jiang, Feng; Liu, Biao; Lu, Jun; Li, Fangfei; Li, Defang; Liang, Chao; Dang, Lei; Liu, Jin; He, Bing; Atik Badshah, Shaikh; Lu, Cheng; He, Xiaojuan; Guo, Baosheng; Zhang, Xiao-Bing; Tan, Weihong; Lu, Aiping; Zhang, Ge

2015-01-01

Aptamers, which can be screened via systematic evolution of ligands by exponential enrichment (SELEX), are superior ligands for molecular recognition due to their high selectivity and affinity. The interest in the use of aptamers as ligands for targeted drug delivery has been increasing due to their unique advantages. Based on their different compositions and preparation methods, aptamer-functionalized targeted drug delivery systems can be divided into two main categories: aptamer-small molecule conjugated systems and aptamer-nanomaterial conjugated systems. In this review, we not only summarize recent progress in aptamer selection and the application of aptamers in these targeted drug delivery systems but also discuss the advantages, challenges and new perspectives associated with these delivery systems. PMID:26473828

Challenges in conducting psychiatry studies in India

PubMed Central

Kharawala, Saifuddin; Dalal, Jeroze

2011-01-01

A large number of psychiatry studies are conducted in India. Psychiatry studies are complex and present unique challenges in the Indian setting. Ethical issues pertaining to the risk of worsening of illness, use of placebo and validity of informed consents are commonly faced. Site selection can be difficult due to the relative paucity of ICH-GCP (International Conference on Harmonisation - Good Clinical Practice) trained psychiatry investigators in India. Recruitment can be challenging due to issues such as strict eligibility criteria, (lack of) availability of caregiver, illness-related considerations, etc. Assessment of the consent capacity of patients is not simple, while structured assessments are not commonly employed. As the illness fluctuates, the consent capacity may change, thus requiring continued assessment of consent capacity. Study patients run the risk of worsening of illness and suicide due to exposure to inactive treatments; this risk is counterbalanced by use of appropriate study designs, as well as the indirect psychotherapeutic support received. Psychiatry studies are associated with a high placebo response. This necessitates conduct of placebo-controlled studies despite the attendant difficulties. Also, the high placebo response is often the cause of failed trials. Rating scales are essential for assessment of drug response. Some rating instruments as well as some rater training procedures may not be suitable for the Indian setting. Technological advancements may increase the procedural complexity but improve the quality of ratings. Psychiatry studies present monitors and auditors with unique scenarios too. Utilization of psychiatry specific training and expertise is recommended to ensure successful conduct of these studies in India. PMID:21584176

Top-down Proteomics in Health and Disease: Challenges and Opportunities

PubMed Central

Gregorich, Zachery R.; Ge, Ying

2014-01-01

Proteomics is essential for deciphering how molecules interact as a system and for understanding the functions of cellular systems in human disease; however, the unique characteristics of the human proteome, which include a high dynamic range of protein expression and extreme complexity due to a plethora of post-translational modifications (PTMs) and sequence variations, make such analyses challenging. An emerging “top-down” mass spectrometry (MS)-based proteomics approach, which provides a “bird’s eye” view of all proteoforms, has unique advantages for the assessment of PTMs and sequence variations. Recently, a number of studies have showcased the potential of top-down proteomics for unraveling of disease mechanisms and discovery of new biomarkers. Nevertheless, the top-down approach still faces significant challenges in terms of protein solubility, separation, and the detection of large intact proteins, as well as the under-developed data analysis tools. Consequently, new technological developments are urgently needed to advance the field of top-down proteomics. Herein, we intend to provide an overview of the recent applications of top-down proteomics in biomedical research. Moreover, we will outline the challenges and opportunities facing top-down proteomics strategies aimed at understanding and diagnosing human diseases. PMID:24723472

Bird Strike Risk for Space Launch Vehicles

NASA Technical Reports Server (NTRS)

Hales, Christy; Czech, Matthew

2017-01-01

Within seconds after liftoff of the Space Shuttle during mission STS-114, a turkey vulture impacted the vehicle's external tank. The contact caused no apparent damage to the shuttle, but the incident led NASA to consider the potential consequences of bird strikes during a shuttle launch. The environment at Kennedy Space Center provides unique bird strike challenges due to the Merritt Island National Wildlife Refuge and the Atlantic Flyway bird migration routes. This presentation will outline an approach for estimating risk resulting from bird strikes to space launch vehicles. The migration routes, types of birds present, altitudes of those birds, exposed area of the launch vehicle, and its capability to withstand impacts all affect the risk due to bird strike. Lessons learned, challenges over lack of data, and significant risk contributors will be discussed.

Spermatic cord dedifferentiated liposarcoma presenting as a recurrent inguinal hernia.

PubMed

Crigger, Chad; Barnard, John; Zaslau, Stanley; Vos, Jeffrey A

2016-12-01

Paratesticular sarcomas are a rare entity and provide a unique clinical challenge due to their slow growing, often painless natural course. Adding to this challenge is the complex anatomy of the scrotum that allows these masses to mimic other conditions, including inguinal hernia, cysts, or fluid collections. We report such a case and our approach to an 83-year-old male with dedifferentiated liposarcoma of the spermatic cord with a history of inguinal hernia. In doing so, we highlight the need for thorough evaluation of scrotal masses and the management of these rare, though well-described, tumors.

Genesis, challenges and opportunities for colloidal lead halide perovskite nanocrystals

NASA Astrophysics Data System (ADS)

Akkerman, Quinten A.; Rainò, Gabriele; Kovalenko, Maksym V.; Manna, Liberato

2018-05-01

Lead halide perovskites (LHPs) in the form of nanometre-sized colloidal crystals, or nanocrystals (NCs), have attracted the attention of diverse materials scientists due to their unique optical versatility, high photoluminescence quantum yields and facile synthesis. LHP NCs have a `soft' and predominantly ionic lattice, and their optical and electronic properties are highly tolerant to structural defects and surface states. Therefore, they cannot be approached with the same experimental mindset and theoretical framework as conventional semiconductor NCs. In this Review, we discuss LHP NCs historical and current research pursuits, challenges in applications, and the related present and future mitigation strategies explored.

Pain management in the geriatric population.

PubMed

Borsheski, Robert; Johnson, Quinn L

2014-01-01

Pain is a highly prevalent and clinically important problem in the elderly. Unfortunately, due to difficulties in assessing pain in geriatric patients, the complexities of multiple comorbidities, and the high prevalence of polypharmacy, many practitioners are reluctant to treat pain aggressively in this unique patient population. Safe and effective treatment therefore, requires a working knowledge of the physiologic changes associated with aging, the challenges of accurately assessing pain, the unique effects of common therapeutic agents upon the elderly as well as the importance of adjunctive therapies. The following review is intended to provide the practitioner with practical knowledge for safer and more effective treatment of pain.

Student Engagement in a Large Classroom: Using Technology to Generate a Hybridized Problem- Based Learning Experience in a Large First Year Undergraduate Class

ERIC Educational Resources Information Center

Fukuzawa, Sherry; Boyd, Cleo

2016-01-01

Large first year undergraduate courses have unique challenges in the promotion of student engagement and self-directed learning due to resource constraints that prohibit small group discussions with instructors. The Monthly Virtual Mystery was developed to increase student engagement in a large (N = 725) first year undergraduate class in…

Climate change in the age of humans

Treesearch

J. Curt Stager

2014-01-01

The Anthropocene epoch presents a mix of old and new challenges for the world’s forests. Climatic instability has typified most of the Cenozoic Era but today’s situation is unique due to the presence of billions of humans on the planet. The potential rate and magnitude of future warming driven by continued fossil fuel combustion could be unprecedented during the last...

Planetary Gearbox Fault Diagnosis Using a Single Piezoelectric Strain Sensor

DTIC Science & Technology

2014-12-23

However, the fault detection of planetary gearbox is very complicate since the c omplex nature of dynamic rolling structure of p lanetary gearbox...vibration transfer paths due to the unique dynamic structure of rotating planet gears. Therefore, it is difficult to diagnose PGB faults via vibration...al. 2014). To overcome the above mentioned challenges in developing effective PGB fau lt diagnosis capability , a research investigation on

Evaluation on the Presence of Nano Silver Particle in Improving a Conventional Water-based Drilling Fluid

NASA Astrophysics Data System (ADS)

Husin, H.; Ahmad, N.; Jamil, N.; Chyuan, O. H.; Roslan, A.

2018-05-01

Worldwide demand in oil and gas energy consumption has been driving many of oil and gas companies to explore new oil and gas resource field in an ultra-deep water environment. As deeper well is drilled, more problems and challenges are expected. The successful of drilling operation is highly dependent on properties of drilling fluids. As a way to operate drilling in challenging and extreme surroundings, nanotechnology with their unique properties is employed. Due to unique physicochemical, electrical, thermal, hydrodynamic properties and exceptional interaction potential of nanomaterials, nanoparticles are considered to be the most promising material of choice for smart fluid design for oil and gas field application. Throughout this paper, the effect of nano silver particle in improving a conventional water based drilling fluid was evaluated. Results showed that nano silver gave a significant improvement to the conventional water based drilling fluid in terms of its rheological properties and filtration test performance.

Crew Exploration Vehicle Environmental Control and Life Support Fire Protection Approach

NASA Technical Reports Server (NTRS)

Lewis, John F.; Barido, Richard; Tuan, George C.

2007-01-01

As part of preparing for the Crew Exploration Vehicle (CEV), the National Aeronautics and Space Administration (NASA) worked on developing the requirements to manage the fire risk. The new CEV poses unique challenges to current fire protection systems. The size and configuration of the vehicle resembles the Apollo capsule instead of the current Space Shuttle or the International Space Station. The smaller free air volume and fully cold plated avionic bays of the CEV requires a different approach in fire protection than the ones currently utilized. The fire protection approach discussed in this paper incorporates historical lessons learned and fire detection and suppression system design philosophy spanning from Apollo to the International Space Station. Working with NASA fire and materials experts, this approach outlines the best requirements for both the closed out area of the vehicle, such as the avionics bay, and the crew cabin area to address the unique challenges due to the size and configuration of the CEV.

Addressing the paradox of the team innovation process: A review and practical considerations.

PubMed

Thayer, Amanda L; Petruzzelli, Alexandra; McClurg, Caitlin E

2018-01-01

Facilitating team innovation is paramount to promoting progress in the science, technology, engineering, and math fields, as well as advancing national health, safety, prosperity, and welfare. However, innovation teams face a unique set of challenges due to the novelty and uncertainty that is core to the definition of innovation, as well as the paradoxical nature of idea generation and idea implementation processes. These and other challenges must be overcome for innovation teams to realize their full potential for producing change. The purpose of this review is, thus, to provide insight into the unique context that these teams function within and provide an integrative, evidence-based, and practically useful, organizing heuristic that focuses on the most important considerations for facilitating team innovation. Finally, we provide practical guidance for psychologists, organizations, practitioners, scientists, educators, policymakers, and others who employ teams to produce novel, innovative solutions to today's problems. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Robust Optical Recognition of Cursive Pashto Script Using Scale, Rotation and Location Invariant Approach

PubMed Central

Ahmad, Riaz; Naz, Saeeda; Afzal, Muhammad Zeshan; Amin, Sayed Hassan; Breuel, Thomas

2015-01-01

The presence of a large number of unique shapes called ligatures in cursive languages, along with variations due to scaling, orientation and location provides one of the most challenging pattern recognition problems. Recognition of the large number of ligatures is often a complicated task in oriental languages such as Pashto, Urdu, Persian and Arabic. Research on cursive script recognition often ignores the fact that scaling, orientation, location and font variations are common in printed cursive text. Therefore, these variations are not included in image databases and in experimental evaluations. This research uncovers challenges faced by Arabic cursive script recognition in a holistic framework by considering Pashto as a test case, because Pashto language has larger alphabet set than Arabic, Persian and Urdu. A database containing 8000 images of 1000 unique ligatures having scaling, orientation and location variations is introduced. In this article, a feature space based on scale invariant feature transform (SIFT) along with a segmentation framework has been proposed for overcoming the above mentioned challenges. The experimental results show a significantly improved performance of proposed scheme over traditional feature extraction techniques such as principal component analysis (PCA). PMID:26368566

OMV man/system simulation integration: A preliminary analysis and recommendation

NASA Technical Reports Server (NTRS)

Rogers, Jon G.

1988-01-01

The Orbital Maneuvering Vehicle (OMV) presents a series of challenges to the human operator. Some are unique to the OMV system itself, and are largely due to remote control versus control from the cockpit. Other challenges are not necessarily unique to the OMV, but are characteristic of many man-machine space flight systems. All of these challenges affect the operator's ability to perform his portion of the mission, and could lead to human error which might jeopardize the vehicle, mission, or both. It is imperative to make every effort to design the control and displays to facilitate the operator's task. The experimental program should address the perceptual, mediational, and motor dimensions of operator performance. With this in mind, a literature review with relevant design considerations was initiated, and a comprehensive outline of control/display parameters were developed. Out of this, a series of questions not answered in the literature was derived which can be converted into experimental protocols for the simulation program. A major task of the aircraft pilot as well as the OMV operator is prediction. Certain display principles have proved to enhance the pilot's ability to predict. A brief examination of some of these principles in relationship to OMV may be useful.

Nanotechnology: Opportunities and Challenges

NASA Technical Reports Server (NTRS)

Meyyappan, Meyya

2003-01-01

Nanotechnology seeks to exploit novel physical, chemical, biological, mechanical, electrical, and other properties, which arise primarily due to the nanoscale nature of certain materials. A key example is carbon nanotubes (CNTs) which exhibit unique electrical and extraordinary mechanical properties and offer remarkable potential for revolutionary applications in electronics devices, computing, and data storage technology, sensors, composites, nanoelectromechanical systems (NEMS), and as tip in scanning probe microscopy (SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization, and applications touch upon all disciplines of science and engineering. This presentation will provide an overview and progress report on this and other major research candidates in Nanotechnology and address opportunities and challenges ahead.

Phospholipids at the Interface: Current Trends and Challenges

PubMed Central

Pichot, Roman; Watson, Richard L.; Norton, Ian T.

2013-01-01

Phospholipids are one of the major structural elements of biological membranes. Due to their amphiphilic character, they can adopt various molecular assemblies when dispersed in water, such as bilayer vesicles or micelles, which give them unique interfacial properties and render them very attractive in terms of foam or emulsion stabilization. This article aims at reviewing the properties of phospholipids at the air/water and oil/water interfaces, as well as the recent advances in using these natural components as stabilizers, alone or in combination with other compounds such as proteins. A discussion regarding the challenges and opportunities offered by phospholipids-stabilized structure concludes the review. PMID:23736688

Biotechnological Applications of Marine Enzymes From Algae, Bacteria, Fungi, and Sponges.

PubMed

Parte, S; Sirisha, V L; D'Souza, J S

Diversity is the hallmark of all life forms that inhabit the soil, air, water, and land. All these habitats pose their unique inherent challenges so as to breed the "fittest" creatures. Similarly, the biodiversity from the marine ecosystem has evolved unique properties due to challenging environment. These challenges include permafrost regions to hydrothermal vents, oceanic trenches to abyssal plains, fluctuating saline conditions, pH, temperature, light, atmospheric pressure, and the availability of nutrients. Oceans occupy 75% of the earth's surface and harbor most ancient and diverse forms of organisms (algae, bacteria, fungi, sponges, etc.), serving as an excellent source of natural bioactive molecules, novel therapeutic compounds, and enzymes. In this chapter, we introduce enzyme technology, its current state of the art, unique enzyme properties, and the biocatalytic potential of marine algal, bacterial, fungal, and sponge enzymes that have indeed boosted the Marine Biotechnology Industry. Researchers began exploring marine enzymes, and today they are preferred over the chemical catalysts for biotechnological applications and functions, encompassing various sectors, namely, domestic, industrial, commercial, and healthcare. Next, we summarize the plausible pros and cons: the challenges encountered in the process of discovery of the potent compounds and bioactive metabolites such as biocatalysts/enzymes of biomedical, therapeutic, biotechnological, and industrial significance. The field of Marine Enzyme Technology has recently assumed importance, and if it receives further boost, it could successfully substitute other chemical sources of enzymes useful for industrial and commercial purposes and may prove as a beneficial and ecofriendly option. With appropriate directions and encouragement, marine enzyme technology can sustain the rising demand for enzyme production while maintaining the ecological balance, provided any undesired exploitation of the marine ecosystem is avoided. © 2017 Elsevier Inc. All rights reserved.

Synthesis, functionalization, and applications of metal-organic frameworks in biomedicine.

PubMed

Chen, Wei; Wu, Chunsheng

2018-02-13

Metal-organic frameworks (MOFs), also known as coordination polymers, have attracted extensive research interest in the past few decades due to their unique physical structures and potentially vast applications. In this review, we outline the recent progress in the synthesis, functionalization and applications of MOFs in biomedicine, mainly focusing on two promising, yet challenging areas, i.e., drug delivery and biosensing applications. A major challenge is the proper functionalization of MOFs with demanding properties suitable for biomedical applications. Extensive studies on MOFs in biomedicine have led to substantial progress in the control of key properties of MOFs such as toxicity, size and shape, and biological stability. Due to their flexible composition, pore size and easy functionalization properties, MOFs can be utilized as key components for the development of various functional systems, and their applications in drug delivery and biosensing are reviewed. Future trends and perspectives in these research areas are also outlined.

Recent developments in the chemistry of sandalwood odorants.

PubMed

Brocke, Constanze; Eh, Marcus; Finke, Anja

2008-06-01

Natural sandalwood oil, a unique and valuable ingredient in fine perfumery, has been the focus of scientific interest for many years. Due to its scarcity and its high price, the search for novel synthetic raw materials imitating the characteristic odor profile of sandalwood oil is as challenging as ever. In this context, the preparation of the novel sandalwood odorants 26, 33, and 39 will be discussed, including their sensory properties and structure-odor relationship.

Porous Hydrogen-Bonded Organic Frameworks.

PubMed

Han, Yi-Fei; Yuan, Ying-Xue; Wang, Hong-Bo

2017-02-13

Ordered porous solid-state architectures constructed via non-covalent supramolecular self-assembly have attracted increasing interest due to their unique advantages and potential applications. Porous metal-coordination organic frameworks (MOFs) are generated by the assembly of metal coordination centers and organic linkers. Compared to MOFs, porous hydrogen-bonded organic frameworks (HOFs) are readily purified and recovered via simple recrystallization. However, due to lacking of sufficiently ability to orientate self-aggregation of building motifs in predictable manners, rational design and preparation of porous HOFs are still challenging. Herein, we summarize recent developments about porous HOFs and attempt to gain deeper insights into the design strategies of basic building motifs.

Challenges and strategies for coping with scleroderma: implications for a scleroderma-specific self-management program.

PubMed

Milette, Katherine; Thombs, Brett D; Maiorino, Kristina; Nielson, Warren R; Körner, Annett; Peláez, Sandra

2018-05-09

The purpose of this study was to explore challenges faced by patients with systemic sclerosis, also called scleroderma, in coping with their disease and the strategies they used to face those challenges. Five focus groups were held with scleroderma patients (4 groups, n = 34) and health care professionals who have experience treating scleroderma (1 group, n = 8). Participants' discussions were recorded, transcribed and analyzed using thematic analysis. Participants reported challenges accessing information (e.g., knowledgeable specialists), dealing with negative emotions (e.g., stress due to misunderstandings with loved ones), and accessing resources (e.g., helpful products or devices). Strategies for overcoming challenges were also discussed (e.g., advocating for own needs). When faced with significant challenges while coping with scleroderma, patients develop strategies to manage better and improve their quality of life. To help them cope, patients would benefit from easier access to supportive interventions, including tailored scleroderma self-management programs. Although the challenges experienced by patients with scleroderma are unique, findings from this study might help better understand patients' perspectives regarding coping and disease management for other chronic diseases as well. Implications for Rehabilitation People living with rare diseases, including the rare autoimmune disease scleroderma, face unique challenges and often do not have access to disease-specific educational or other support resources. People with scleroderma report that they face challenges in accessing information, including knowledgeable healthcare providers; managing difficult social interactions and negative emotions; and accessing resources. Strategies employed by scleroderma patients to overcome these challenges include seeking connections to other people with scleroderma or scleroderma patient organizations, actively seeking out local resources, and learning to communicate and advocate more effectively. Rehabilitation professionals can support people with scleroderma by providing them with information on connecting with scleroderma patient organizations or by facilitating local patient support networks.

Review of Electronics Based on Single-Walled Carbon Nanotubes.

PubMed

Cao, Yu; Cong, Sen; Cao, Xuan; Wu, Fanqi; Liu, Qingzhou; Amer, Moh R; Zhou, Chongwu

2017-08-14

Single-walled carbon nanotubes (SWNTs) are extremely promising materials for building next-generation electronics due to their unique physical and electronic properties. In this article, we will review the research efforts and achievements of SWNTs in three electronic fields, namely analog radio-frequency electronics, digital electronics, and macroelectronics. In each SWNT-based electronic field, we will present the major challenges, the evolutions of the methods to overcome these challenges, and the state-of-the-art of the achievements. At last, we will discuss future directions which could lead to the broad applications of SWNTs. We hope this review could inspire more research on SWNT-based electronics, and accelerate the applications of SWNTs.

Transforming Teaching Challenges into Learning Opportunities: Interdisciplinary Reflective Collaboration

ERIC Educational Resources Information Center

Callaghan, Ronel

2015-01-01

Teaching in higher education poses unique sets of challenges, especially for academics in the engineering, built sciences and information science education disciplines. This article focuses on how reflective collaboration can support academics in their quest to find unique solutions to challenges in different academic contexts. A reflective…

Probability and surprisal in auditory comprehension of morphologically complex words.

PubMed

Balling, Laura Winther; Baayen, R Harald

2012-10-01

Two auditory lexical decision experiments document for morphologically complex words two points at which the probability of a target word given the evidence shifts dramatically. The first point is reached when morphologically unrelated competitors are no longer compatible with the evidence. Adapting terminology from Marslen-Wilson (1984), we refer to this as the word's initial uniqueness point (UP1). The second point is the complex uniqueness point (CUP) introduced by Balling and Baayen (2008), at which morphologically related competitors become incompatible with the input. Later initial as well as complex uniqueness points predict longer response latencies. We argue that the effects of these uniqueness points arise due to the large surprisal (Levy, 2008) carried by the phonemes at these uniqueness points, and provide independent evidence that how cumulative surprisal builds up in the course of the word co-determines response latencies. The presence of effects of surprisal, both at the initial uniqueness point of complex words, and cumulatively throughout the word, challenges the Shortlist B model of Norris and McQueen (2008), and suggests that a Bayesian approach to auditory comprehension requires complementation from information theory in order to do justice to the cognitive cost of updating probability distributions over lexical candidates. Copyright © 2012 Elsevier B.V. All rights reserved.

Enhancing data from commercial space flights (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sherman, Ariel; Paolini, Aaron; Kozacik, Stephen; Kelmelis, Eric J.

2017-05-01

Video tracking of rocket launches inherently must be done from long range. Due to the high temperatures produced, cameras are often placed far from launch sites and their distance to the rocket increases as it is tracked through the flight. Consequently, the imagery collected is generally severely degraded by atmospheric turbulence. In this talk, we present our experience in enhancing commercial space flight videos. We will present the mission objectives, the unique challenges faced, and the solutions to overcome them.

Inorganic Nanoparticles in Cancer Therapy

PubMed Central

Bhattacharyya, Sanjib; Kudgus, Rachel A.; Bhattacharya, Resham; Mukherjee, Priyabrata

2011-01-01

Nanotechnology is an evolving field with enormous potential for biomedical applications. The growing interest to use inorganic nanoparticles in medicine is due to the unique size and shape-dependent optoelectronic properties. Herein, we will focus on gold, silver and platinum nanoparticles, discussing recent developments for therapeutic applications with regard to cancer in terms of nanoparticles being used as a delivery vehicle as well as therapeutic agents. We will also discuss some of the key challenges to be addressed in future studies. PMID:21104301

Recent advances in the fabrication and structure-specific applications of graphene-based inorganic hybrid membranes.

PubMed

Zhao, Xinne; Zhang, Panpan; Chen, Yuting; Su, Zhiqiang; Wei, Gang

2015-03-12

The preparation and applications of graphene (G)-based materials are attracting increasing interests due to their unique electronic, optical, magnetic, thermal, and mechanical properties. Compared to G-based hybrid and composite materials, G-based inorganic hybrid membrane (GIHM) offers enormous advantages ascribed to their facile synthesis, planar two-dimensional multilayer structure, high specific surface area, and mechanical stability, as well as their unique optical and mechanical properties. In this review, we report the recent advances in the technical fabrication and structure-specific applications of GIHMs with desirable thickness and compositions. In addition, the advantages and disadvantages of the methods utilized for creating GIHMs are discussed in detail. Finally, the potential applications and key challenges of GIHMs for future technical applications are mentioned.

Chinese ethnic meat products: Continuity and development.

PubMed

Zeng, Weicai; Wen, Wenting; Deng, Yue; Tian, Yuanyuan; Sun, Honghu; Sun, Qun

2016-10-01

With their distinctive sensory characterizations and unique processing technologies, Chinese ethnic meat products possess great potential for development and continuity in modern China's meat industry. Due to the greater demand for meat products and higher quality and safety concerns in economically fast growing China, the development and continuity of ethnic meat products face its own unique challenges. In this review, the classification of typical ethnic products and their characteristics, and the research progress on their quality and processing technologies are discussed. The application of innovative and green technologies to improve the safety and quality of ethnic meat products for greater industrialization and sustainable development is highlighted. Furthermore, the strategy for promoting the production of Chinese ethnic meat products during the next five years is presented. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lichenoid Dermatitis of the Vulva: Diagnosis and Differential Diagnosis for the Gynecologic Pathologist.

PubMed

Lewin, Marc R; Hick, Ryan W; Selim, Maria A

2017-09-01

Inflammatory processes affecting the vulva may present a unique challenge due to location specific changes. Different factors are behind the intricacy in the presentation of vulvar dermatoses. First, the vulva is lined by different epithelia (hair-bearing keratinized epithelium, modified mucosa, and mucosa). Furthermore, among other factors, this organ is exposed to friction, occlusion, and trauma. Lastly, as there is a tendency to look for health care advice at an advanced stage of the disease, the lesion may be modified by secondary changes due to self-treatment. This article describes the clinical presentation and pathologic features of vulvar dermatoses with a lichenoid pattern and highlights practical points for their diagnoses.

Three-Dimensional Printing of Prosthetic Hands for Children.

PubMed

Burn, Matthew B; Ta, Anderson; Gogola, Gloria R

2016-05-01

Children with hand reductions, whether congenital or traumatic, have unique prosthetic needs. They present a challenge because of their continually changing size due to physical growth as well as changing needs due to psychosocial development. Conventional prosthetics are becoming more technologically advanced and increasingly complex. Although these are welcome advances for adults, the concomitant increases in weight, moving parts, and cost are not beneficial for children. Pediatric prosthetic needs may be better met with simpler solutions. Three-dimensional printing can be used to fabricate rugged, light-weight, easily replaceable, and very low cost assistive hands for children. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Extending Synthetic Routes for Oligosaccharides by Enzyme, Substrate and Reaction Engineering

NASA Astrophysics Data System (ADS)

Seibel, Jürgen; Jördening, Hans-Joachim; Buchholz, Klaus

The integration of all relevant tools for bioreaction engineering has been a recent challenge. This approach should notably favor the production of oligo- and polysaccharides, which is highly complex due to the requirements of regio- and stereoselectivity. Oligosaccharides (OS) and polysaccharides (PS) have found many interests in the fields of food, pharmaceuticals, and cosmetics due to different specific properties. Food, sweeteners, and food ingredients represent important sectors where OS are used in major amounts. Increasing attention has been devoted to the sophisticated roles of OS and glycosylated compounds, at cell or membrane surfaces, and their function, e.g., in infection and cancer proliferation. The challenge for synthesis is obvious, and convenient approaches using cheap and readily available substrates and enzymes will be discussed. We report on new routes for the synthesis of oligosaccharides (OS), with emphasis on enzymatic reactions, since they offer unique properties, proceeding highly regio- and stereoselective in water solution, and providing for high yields in general.

Challenges of Big Data Analysis.

PubMed

Fan, Jianqing; Han, Fang; Liu, Han

2014-06-01

Big Data bring new opportunities to modern society and challenges to data scientists. On one hand, Big Data hold great promises for discovering subtle population patterns and heterogeneities that are not possible with small-scale data. On the other hand, the massive sample size and high dimensionality of Big Data introduce unique computational and statistical challenges, including scalability and storage bottleneck, noise accumulation, spurious correlation, incidental endogeneity, and measurement errors. These challenges are distinguished and require new computational and statistical paradigm. This article gives overviews on the salient features of Big Data and how these features impact on paradigm change on statistical and computational methods as well as computing architectures. We also provide various new perspectives on the Big Data analysis and computation. In particular, we emphasize on the viability of the sparsest solution in high-confidence set and point out that exogeneous assumptions in most statistical methods for Big Data can not be validated due to incidental endogeneity. They can lead to wrong statistical inferences and consequently wrong scientific conclusions.

Challenges of Big Data Analysis

PubMed Central

Fan, Jianqing; Han, Fang; Liu, Han

2014-01-01

Big Data bring new opportunities to modern society and challenges to data scientists. On one hand, Big Data hold great promises for discovering subtle population patterns and heterogeneities that are not possible with small-scale data. On the other hand, the massive sample size and high dimensionality of Big Data introduce unique computational and statistical challenges, including scalability and storage bottleneck, noise accumulation, spurious correlation, incidental endogeneity, and measurement errors. These challenges are distinguished and require new computational and statistical paradigm. This article gives overviews on the salient features of Big Data and how these features impact on paradigm change on statistical and computational methods as well as computing architectures. We also provide various new perspectives on the Big Data analysis and computation. In particular, we emphasize on the viability of the sparsest solution in high-confidence set and point out that exogeneous assumptions in most statistical methods for Big Data can not be validated due to incidental endogeneity. They can lead to wrong statistical inferences and consequently wrong scientific conclusions. PMID:25419469

Inferring glacial flow pathways with DNA-labelled microparticle tracers at the Wolverine Glacier in Alaska

NASA Astrophysics Data System (ADS)

McNew, Coy; Dahlke, Helen; O'Neel, Shad; McLaughlin, Seanna

2017-04-01

Though recent advances have been made in the understanding of glacial hydrologic pathways, accurate predictions and descriptions of glacial hydrologic processes remain a challenge. The most common method to investigate subglacial pathways tends to be dye tracing. Due to the limited number of unique dye tracers, the photodegradability of some, and the typically long breakthrough times associated with such pathways, dye tracing experiments tend to be restricted to only a few injections, and therefore the contribution of only a few pathways can be investigated at a time. Five uniquely DNA-labelled microparticle tracers were injected in five different locations throughout the Wolverine Glacier ablation zone, one of two "benchmark glaciers" in Alaska and the subject of long term study by the United States Geological Survey. Stream water was sampled several hundred meters downstream at regular intervals and later analyzed for the presence of each tracer. Since each tracer was tagged with a unique sequence of DNA, the contribution of each to the total outflow can be quantified independently. Preliminary results indicate relatively short transit times, suggesting that the ablation zone is characterized by a high-volume (low pressure) subglacial hydrologic network (i.e. conduits). Here we present the results of the study, the challenges faced, and a discussion on the potential of the DNA-labelled microtracer technology.

Embolization of palpebral and orbito-frontal fistulas: technical and anatomical considerations in treating high-flow superficial skin lesions with liquid embolics.

PubMed

Samaniego, Edgar A; Fisher, Mark; Hasan, David; Guerrero, Waldo R; Fifi, Johanna T; Bottani, Laura; Ortega-Gutierrez, Santiago

2018-03-01

The treatment of palpebral and periorbital fistulas may be challenging due to the presence of multiple anastomosis with eloquent ophthalmic and intracranial vascular territories. Moreover, cosmetic and functional characteristics of this area pose unique challenges to open surgical approaches and endovascular therapy. We review the advantages and disadvantages of different liquid embolics in treating palpebral and periorbital fistulas as we describe three successfully treated cases. Moreover, we describe important anatomical landmarks that should be considered at the time of treatment of these lesions. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Time-local equation for exact time-dependent optimized effective potential in time-dependent density functional theory

NASA Astrophysics Data System (ADS)

Liao, Sheng-Lun; Ho, Tak-San; Rabitz, Herschel; Chu, Shih-I.

2017-04-01

Solving and analyzing the exact time-dependent optimized effective potential (TDOEP) integral equation has been a longstanding challenge due to its highly nonlinear and nonlocal nature. To meet the challenge, we derive an exact time-local TDOEP equation that admits a unique real-time solution in terms of time-dependent Kohn-Sham orbitals and effective memory orbitals. For illustration, the dipole evolution dynamics of a one-dimension-model chain of hydrogen atoms is numerically evaluated and examined to demonstrate the utility of the proposed time-local formulation. Importantly, it is shown that the zero-force theorem, violated by the time-dependent Krieger-Li-Iafrate approximation, is fulfilled in the current TDOEP framework. This work was partially supported by DOE.

Hydrogel scaffolds for tissue engineering: Progress and challenges

PubMed Central

El-Sherbiny, Ibrahim M.; Yacoub, Magdi H.

2013-01-01

Designing of biologically active scaffolds with optimal characteristics is one of the key factors for successful tissue engineering. Recently, hydrogels have received a considerable interest as leading candidates for engineered tissue scaffolds due to their unique compositional and structural similarities to the natural extracellular matrix, in addition to their desirable framework for cellular proliferation and survival. More recently, the ability to control the shape, porosity, surface morphology, and size of hydrogel scaffolds has created new opportunities to overcome various challenges in tissue engineering such as vascularization, tissue architecture and simultaneous seeding of multiple cells. This review provides an overview of the different types of hydrogels, the approaches that can be used to fabricate hydrogel matrices with specific features and the recent applications of hydrogels in tissue engineering. Special attention was given to the various design considerations for an efficient hydrogel scaffold in tissue engineering. Also, the challenges associated with the use of hydrogel scaffolds were described. PMID:24689032

Challenges for Engineering Design, Construction, and Maintenance of Infrastructure in Afghanistan

DTIC Science & Technology

2010-11-01

applied engineering expertise that collectively can solve challenging infra- structure problems. USACE-ERDC’s researchers and engineers are field...Development Center (ERDC) possesses a unique combination of basic research and applied engineering expertise that collectively can solve challenging...restoration, and other projects. The USACE Engineer Research and Development Center (ERDC) possesses a unique combination of basic research and applied

Multi-Drug-Resistant Klebsiella pneumoniae Pancreatitis: A New Challenge in a Serious Surgical Infection

PubMed Central

Tugal, Derin; Lynch, Melanie; Hujer, Andrea M.; Rudin, Susan; Perez, Federico

2015-01-01

Abstract Background: Klebsiella pneumoniae is an important cause of nosocomial infections, but its role in severe acute pancreatitis (SAP) is not well defined. Few cases of K. pneumoniae associated SAP have been reported. Due to the emergence of extended-spectrum beta-lactamases (ESBLs) and carbapenemases, treatment of multidrug-resistant (MDR) K. pneumoniae presents a challenge. Tigecycline and colistin have gained recent attention for their broad-spectrum antimicrobial activity. Methods: We describe a case of SAP due to K. pneumoniae bearing K. pneumoniae carbapenemase (KPC) treated successfully with colistin plus tigecycline and offer a review of similar experiences published in the literature. Results: The case reported herein required surgical drainage of multiple pancreatic abscesses and treatment with tigecycline and colistin. Our comparative analysis revealed a number of unique features associated with SAP due to K. pneumoniae: 1) underlying pancreatic injury, 2) multiple drug resistance determinants and virulence factors that complicate treatment, and 3) surgical debridement as a requirement for cure. Conclusion: As the prevalence of K. pneumoniae bearing KPC continues to increase in the healthcare setting, SAP caused by this MDR pathogen will become more common. Tigecycline plus colistin was a successful antibiotic regimen for the treatment of SAP due to K. pneumoniae bearing KPC. PMID:24850293

Exploration Challenges: Transferring Ground Repair Techniques to Space Flight Application

NASA Technical Reports Server (NTRS)

McLemore, Carole A.; Kennedy, James P.; Rose, Frederick A.; Evans, Brian W.

2007-01-01

Fulfilling NASA's Vision for Space Exploration will demand an extended presence in space at distances from our home planet that exceed our current experience in space logistics and maintenance. The ability to perform repairs in lieu of the customary Orbital Replacement Unit (ORU) process where a faulty part is replaced will be elevated from contingency to routine to sustain operations. The use and cost effectiveness of field repairs for ground based operations in industry and the military have advanced with the development of technology in new materials, new repair techniques and new equipment. The unique environments, accessibility constraints and Extra Vehicular Activity (EVA) issues of space operations will require extensive assessment and evolution of these technologies to provide an equivalent and expected level of assurance to mission success. Challenges include the necessity of changes in design philosophy and policy, extremes in thermal cycling, disruptive forces (such as static charge and wind entrainment) on developed methods for control of materials, dramatically increased volatility of chemicals for cleaning and other compounds due to extremely low pressures, the limits imposed on dexterity and maneuverability by current EVA equipment and practices, and the necessity of unique verification methodology. This paper describes these challenges in and discusses the effects on the established ground techniques for repair. The paper also describes the leading repair methodology candidates and their beneficial attributes for resolving these issues with the evolution of technology.

Gaseotransmitters: New Frontiers for Translational Science

PubMed Central

Szabo, Csaba

2011-01-01

Research into the biology of the endogenous gaseous mediators nitric oxide (NO), carbon monoxide (CO) and hydrogen sulfide (H2S) has significantly expanded over the last decade. A number of drugs (already in clinical use) and drug candidates (in preclinical or clinical trials) exert their effects via donation of these mediators and/or via modulation of their intracellular second messenger pathways. Due to their important biological roles, gaseotransmitters offer many therapeutic opportunities. However, their unique chemical and pharmacological properties can also represent unusual challenges for translational science. PMID:21106939

Boundary fitting based segmentation of fluorescence microscopy images

NASA Astrophysics Data System (ADS)

Lee, Soonam; Salama, Paul; Dunn, Kenneth W.; Delp, Edward J.

2015-03-01

Segmentation is a fundamental step in quantifying characteristics, such as volume, shape, and orientation of cells and/or tissue. However, quantification of these characteristics still poses a challenge due to the unique properties of microscopy volumes. This paper proposes a 2D segmentation method that utilizes a combination of adaptive and global thresholding, potentials, z direction refinement, branch pruning, end point matching, and boundary fitting methods to delineate tubular objects in microscopy volumes. Experimental results demonstrate that the proposed method achieves better performance than an active contours based scheme.

Challenges of Pre- and Post-Test Counseling for Orthodox Jewish Individuals in the Premarital Phase.

PubMed

Rose, E; Schreiber-Agus, N; Bajaj, K; Klugman, S; Goldwaser, T

2016-02-01

The Jewish community has traditionally taken ownership of its health, and has taken great strides to raise awareness about genetic issues that affect the community, such as Tay-Sachs disease and Hereditary Breast and Ovarian Cancer syndrome. Thanks in part to these heightened awareness efforts, many Orthodox Jewish individuals are now using genetics services as they begin to plan their families. Due to unique cultural and religious beliefs and perceptions, the Orthodox Jewish patients who seek genetic counseling face many barriers to a successful counseling session, and often seek the guidance of programs such as the Program for Jewish Genetic Health (PJGH). In this article, we present clinical vignettes from the PJGH's clinical affiliate, the Reproductive Genetics practice at the Montefiore Medical Center. These cases highlight unique features of contemporary premarital counseling and screening within the Orthodox Jewish Community, including concerns surrounding stigma, disclosure, "marriageability," the use of reproductive technologies, and the desire to include a third party in decision making. Our vignettes demonstrate the importance of culturally-sensitive counseling. We provide strategies and points to consider when addressing the challenges of pre- and post-test counseling as it relates to genetic testing in this population.

Challenges and models in supporting logistics system design for dedicated-biomass-based bioenergy industry.

PubMed

Zhu, Xiaoyan; Li, Xueping; Yao, Qingzhu; Chen, Yuerong

2011-01-01

This paper analyzed the uniqueness and challenges in designing the logistics system for dedicated biomass-to-bioenergy industry, which differs from the other industries, due to the unique features of dedicated biomass (e.g., switchgrass) including its low bulk density, restrictions on harvesting season and frequency, content variation with time and circumambient conditions, weather effects, scattered distribution over a wide geographical area, and so on. To design it, this paper proposed a mixed integer linear programming model. It covered from planting and harvesting switchgrass to delivering to a biorefinery and included the residue handling, concentrating on integrating strategic decisions on the supply chain design and tactical decisions on the annual operation schedules. The present numerical examples verified the model and demonstrated its use in practice. This paper showed that the operations of the logistics system were significantly different for harvesting and non-harvesting seasons, and that under the well-designed biomass logistics system, the mass production with a steady and sufficient supply of biomass can increase the unit profit of bioenergy. The analytical model and practical methodology proposed in this paper will help realize the commercial production in biomass-to-bioenergy industry. Copyright © 2010 Elsevier Ltd. All rights reserved.

Challenging the Metallothionein (MT) Gene of Biomphalaria glabrata: Unexpected Response Patterns Due to Cadmium Exposure and Temperature Stress.

PubMed

Niederwanger, Michael; Dvorak, Martin; Schnegg, Raimund; Pedrini-Martha, Veronika; Bacher, Katharina; Bidoli, Massimo; Dallinger, Reinhard

2017-08-11

Metallothioneins (MTs) are low-molecular-mass, cysteine-rich, metal binding proteins. In most animal species, they are involved in metal homeostasis and detoxification, and provide protection from oxidative stress. Gastropod MTs are highly diversified, exhibiting unique features and adaptations like metal specificity and multiplications of their metal binding domains. Here, we show that the MT gene of Biomphalaria glabrata , one of the largest MT genes identified so far, is composed in a unique way. The encoding for an MT protein has a three-domain structure and a C-terminal, Cys-rich extension. Using a bioinformatic approach involving structural and in silico analysis of putative transcription factor binding sites (TFBs), we found that this MT gene consists of five exons and four introns. It exhibits a regulatory promoter region containing three metal-responsive elements (MREs) and several TFBs with putative involvement in environmental stress response, and regulation of gene expression. Quantitative real-time polymerase chain reaction (qRT-PCR) data indicate that the MT gene is not inducible by cadmium (Cd) nor by temperature challenges (heat and cold), despite significant Cd uptake within the midgut gland and the high Cd tolerance of metal-exposed snails.

Challenging the Metallothionein (MT) Gene of Biomphalaria glabrata: Unexpected Response Patterns Due to Cadmium Exposure and Temperature Stress

PubMed Central

Dvorak, Martin; Schnegg, Raimund; Pedrini-Martha, Veronika; Bacher, Katharina; Bidoli, Massimo; Dallinger, Reinhard

2017-01-01

Metallothioneins (MTs) are low-molecular-mass, cysteine-rich, metal binding proteins. In most animal species, they are involved in metal homeostasis and detoxification, and provide protection from oxidative stress. Gastropod MTs are highly diversified, exhibiting unique features and adaptations like metal specificity and multiplications of their metal binding domains. Here, we show that the MT gene of Biomphalaria glabrata, one of the largest MT genes identified so far, is composed in a unique way. The encoding for an MT protein has a three-domain structure and a C-terminal, Cys-rich extension. Using a bioinformatic approach involving structural and in silico analysis of putative transcription factor binding sites (TFBs), we found that this MT gene consists of five exons and four introns. It exhibits a regulatory promoter region containing three metal-responsive elements (MREs) and several TFBs with putative involvement in environmental stress response, and regulation of gene expression. Quantitative real-time polymerase chain reaction (qRT-PCR) data indicate that the MT gene is not inducible by cadmium (Cd) nor by temperature challenges (heat and cold), despite significant Cd uptake within the midgut gland and the high Cd tolerance of metal-exposed snails. PMID:28800079

Eleventh annual Warren K. Sinclair keynote address-science, radiation protection and NCRP: building on the past, looking to the future.

PubMed

Bushberg, Jerrold T

2015-02-01

The many reports and other authoritative documents developed and published by the National Council on Radiation Protection and Measurements (NCRP) have been of great service to the nation and the radiation protection community since its Congressional charter was signed into law 50 y ago. There will be a continuing need for NCRP to identify the principles upon which radiation protection is to be based and to provide guidance on best practices for the practical application of those principles for the many beneficial uses of radiation in society. The unique and invaluable resource that is NCRP is in large part due to the selfless dedication and numerous contributions of its Council and scientific committee members. The multidisciplinary composition of these leading experts and their collective input on complex questions provide a unique synergy that results in a comprehensive and well-balanced approach to addressing current and future radiation protection challenges. Subsequent articles in these proceedings covering a broad range of relevant topics will review sentinel accomplishments of the past as well as current work and future challenges that are in keeping with NCRP's mission to advance the science of radiation protection in the public interest.

Challenges of a worksite health promotion project.

PubMed

Gates, Donna M; Brehm, Bonnie J

2010-03-01

It is estimated that American employers spend more than $900 billion annually on health care and that obesity-attributable health care expenditures total $75 billion. The authors discuss a yearlong health promotion research project aimed at obesity and involving eight small manufacturing companies. Three hundred forty-one employees randomly selected at the intervention and control worksites were followed at baseline and at 3, 6, and 12 months for anthropometric measures, lifestyle behaviors, absences, and work performance. The authors conclude that although the worksite offers unique opportunities to develop health promotion programs, these efforts are not without challenges due to the tensions regarding the need to protect and promote health for the population, the increasing concerns over health care costs and access, and the priority to maintain individuals' rights and privacy.

Energy aware swarm optimization with intercluster search for wireless sensor network.

PubMed

Thilagavathi, Shanmugasundaram; Geetha, Bhavani Gnanasambandan

2015-01-01

Wireless sensor networks (WSNs) are emerging as a low cost popular solution for many real-world challenges. The low cost ensures deployment of large sensor arrays to perform military and civilian tasks. Generally, WSNs are power constrained due to their unique deployment method which makes replacement of battery source difficult. Challenges in WSN include a well-organized communication platform for the network with negligible power utilization. In this work, an improved binary particle swarm optimization (PSO) algorithm with modified connected dominating set (CDS) based on residual energy is proposed for discovery of optimal number of clusters and cluster head (CH). Simulations show that the proposed BPSO-T and BPSO-EADS perform better than LEACH- and PSO-based system in terms of energy savings and QOS.

Modular projects and 'mean questions': best practices for advising an International Genetically Engineered Machines team.

PubMed

Tsui, Jennifer; Meyer, Anne S

2016-07-01

In the yearly Internationally Genetically Engineered Machines (iGEM) competition, teams of Bachelor's and Master's students design and build an engineered biological system using DNA technologies. Advising an iGEM team poses unique challenges due to the inherent difficulties of mounting and completing a new biological project from scratch over the course of a single academic year; the challenges in obtaining financial and structural resources for a project that will likely not be fully realized; and conflicts between educational and competition-based goals. This article shares tips and best practices for iGEM team advisors, from two team advisors with very different experiences with the iGEM competition. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Quantitative Approaches to Group Research: Suggestions for Best Practices

ERIC Educational Resources Information Center

McCarthy, Christopher J.; Whittaker, Tiffany A.; Boyle, Lauren H.; Eyal, Maytal

2017-01-01

Rigorous scholarship is essential to the continued growth of group work, yet the unique nature of this counseling specialty poses challenges for quantitative researchers. The purpose of this proposal is to overview unique challenges to quantitative research with groups in the counseling field, including difficulty in obtaining large sample sizes…

Neutralizing antibody fails to impact the course of Ebola virus infection in monkeys.

PubMed

Oswald, Wendelien B; Geisbert, Thomas W; Davis, Kelly J; Geisbert, Joan B; Sullivan, Nancy J; Jahrling, Peter B; Parren, Paul W H I; Burton, Dennis R

2007-01-01

Prophylaxis with high doses of neutralizing antibody typically offers protection against challenge with viruses producing acute infections. In this study, we have investigated the ability of the neutralizing human monoclonal antibody, KZ52, to protect against Ebola virus in rhesus macaques. This antibody was previously shown to fully protect guinea pigs from infection. Four rhesus macaques were given 50 mg/kg of neutralizing human monoclonal antibody KZ52 intravenously 1 d before challenge with 1,000 plaque-forming units of Ebola virus, followed by a second dose of 50 mg/kg antibody 4 d after challenge. A control animal was exposed to virus in the absence of antibody treatment. Passive transfer of the neutralizing human monoclonal antibody not only failed to protect macaques against challenge with Ebola virus but also had a minimal effect on the explosive viral replication following infection. We show that the inability of antibody to impact infection was not due to neutralization escape. It appears that Ebola virus has a mechanism of infection propagation in vivo in macaques that is uniquely insensitive even to high concentrations of neutralizing antibody.

Self Managing Heart Failure in Remote Australia - Translating Concepts into Clinical Practice

PubMed Central

Iyngkaran, Pupalan; Toukhsati, Samia R.; Harris, Melanie; Connors, Christine; Kangaharan, Nadarajan; Ilton, Marcus; Nagel, Tricia; Moser, Debra K.; Battersby, Malcolm

2016-01-01

Congestive heart failure (CHF) is an ambulatory health care condition characterized by episodes of decompensation and is usually without cure. It is a leading cause for morbidity and mortality and the lead cause for hospital admissions in older patients in the developed world. The long-term requirement for medical care and pharmaceuticals contributes to significant health care costs. CHF management follows a hierarchy from physician prescription to allied health, predominately nurse-led, delivery of care. Health services are easier to access in urban compared to rural settings. The differentials for more specialized services could be even greater. Remote Australia is thus faced with unique challenges in delivering CHF best practice. Chronic disease self-management programs (CDSMP) were designed to increase patient participation in their health and alleviate stress on health systems. There have been CDSMP successes with some diseases, although challenges still exist for CHF. These challenges are amplified in remote Australia due to geographic and demographic factors, increased burden of disease, and higher incidence of comorbidities. In this review we explore CDSMP for CHF and the challenges for our region. PMID:27397492

A Theoretical Study of the Hidden Wounds of War: Disenfranchised Grief and the Impact on Nursing Practice

PubMed Central

Aloi, Janice A.

2011-01-01

Combat veterans face enormous challenges upon the return to civilian life, one of which is the ability to integrate incidences of death and killing into a healthy postdeployment life. This paper presents the lived experience of grief and loss resulting from the trauma of war. Social constructionist theory, due to its emphasis on meaning-making, serves as the theoretical framework. The effects of inhibited mourning due to the inability to mourn in combat and lack of nurturing upon returning home are described. Personal excerpts derived from interviews of warfare from veterans that experienced death and killing are presented. It is suggested that combat veterans experience a unique form of grief and therefore require a style of grieving that differs from those that have not served on the battlefield. Regardless of the point of care, nurses are positioned to help with the challenges of readjustment. A better understanding of combat veterans as a disenfranchised group would enable nurses to intervene in ways that contribute to the readjustment process. PMID:22007331

Nanoparticle-Based Manipulation of Antigen-Presenting Cells for Cancer Immunotherapy.

PubMed

Fang, Ronnie H; Kroll, Ashley V; Zhang, Liangfang

2015-11-04

Immunotherapeutic approaches for treating cancer overall have been receiving a considerable amount of interest due to the recent approval of several clinical formulations. Among the different modalities, anticancer vaccination acts by training the body to endogenously generate a response against tumor cells. However, despite the large amount of work that has gone into the development of such vaccines, the near absence of clinically approved formulations highlights the many challenges facing those working in the field. The generation of potent endogenous anticancer responses poses unique challenges due to the similarity between cancer cells and normal, healthy cells. As researchers continue to tackle the limited efficacy of vaccine formulations, fresh and novel approaches are being sought after to address many of the underlying problems. Here the application of nanoparticle technology towards the development of anticancer vaccines is discussed. Specifically, there is a focus on the benefits of using such strategies to manipulate antigen presenting cells (APCs), which are essential to the vaccination process, and how nanoparticle-based platforms can be rationally engineered to elicit appropriate downstream immune responses. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modernization of the Cassini Ground System

NASA Technical Reports Server (NTRS)

Razo, Gus; Fujii, Tammy J.

2014-01-01

The Cassini Spacecraft and its ground system have been operational for over 16 years. Modernization presents several challenges due to the personnel, processes, and tools already invested and embedded into the current ground system structure. Every mission's ground system has its own unique complexities and challenges, involving various organizational units. As any mission from its inception to its execution, schedules are always tight. This forces GDS engineers to implement a working ground system that is not necessarily fully optimized. Ground system challenges increase as technology evolves and cyber threats become more sophisticated. Cassini's main challenges were due to its ground system existing before many security requirements were levied on the multi-mission tools and networks. This caused a domino effect on Cassini GDS tools that relied on outdated technological features. In the aerospace industry reliable and established technology is preferred over innovative yet less proven technology. Loss of data for a spacecraft mission can be catastrophic; therefore, there is a reluctance to make changes and updates to the ground system. Nevertheless, all missions and associated teams face the need to modernize their processes and tools. Systems development methods from well-known system analysis and design principles can be applied to many missions' ground systems. Modernization should always be considered, but should be done in such a way that it does not affect flexibility nor interfere with established practices. Cassini has accomplished a secure and efficient ground data system through periodic updates. The obstacles faced while performing the modernization of the Cassini ground system will be outlined, as well as the advantages and challenges that were encountered.

Physiological and Psychological Challenges of Increasing Physical Activity and Exercise in Patients at Risk of Diabetic Foot Ulcers: A Critical Review

PubMed Central

Crews, Ryan T.; Schneider, Kristin L.; Yalla, Sai V.; Reeves, Neil D.; Vileikyte, Loretta

2017-01-01

Obesity and a sedentary lifestyle are common challenges among individuals at risk of diabetic foot ulcers (DFUs). While substantial research exists on physical activity interventions in adults with diabetes, those at greatest risk for foot ulceration were often excluded or not well-represented. Both at-risk patients and their clinicians may be hesitant to increase physical activity due to their perception of DFU risks. Physical activity is not contraindicated for those at risk of DFU, yet patients at risk present with unique barriers to initiating increases in physical activity. This review focuses upon the physiological and psychological challenges of increasing physical activity and exercise in patients at risk of DFUs. Offloading, diabetic peripheral neuropathy, depression, pain, self-efficacy and social support, DFU risk-specific beliefs and emotions, and research to date on exercise interventions in this population are all discussed. Additionally, recommendations for implementing and researching physical activity interventions for individuals at risk for DFU are provided. PMID:27155091

Measurement and Instrumentation Challenges at X-ray Free Electron Lasers

NASA Astrophysics Data System (ADS)

Feng, Yiping

2015-03-01

X-ray Free Electron Laser sources based on the Self Amplified Spontaneous Emission process are intrinsically chaotic, giving rise to pulse-to-pulse fluctuations in all physical properties, including intensity, position and pointing, spatial and temporal profiles, spectral content, timing, and coherence. These fluctuations represents special challenges to users whose experiments are designed to reveal small changes in the underlying physical quantities, which would otherwise be completely washed out without using the proper diagnostics tools. Due to the X-ray FEL's unique characteristics such as the unprecedented peak power and nearly full spatial coherence, there are many technical challenges in conceiving and implementing these devices that are highly transmissive, provide sufficient signal-to-noise ratio, and most importantly work in the single-shot mode. Portions of this research were carried out at the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory. LCLS is an Office of Science User Facility operated for the U.S. Department of Energy Office of Science by Stanford Univ.

Applications of Single-Cell Sequencing for Multiomics.

PubMed

Xu, Yungang; Zhou, Xiaobo

2018-01-01

Single-cell sequencing interrogates the sequence or chromatin information from individual cells with advanced next-generation sequencing technologies. It provides a higher resolution of cellular differences and a better understanding of the underlying genetic and epigenetic mechanisms of an individual cell in the context of its survival and adaptation to microenvironment. However, it is more challenging to perform single-cell sequencing and downstream data analysis, owing to the minimal amount of starting materials, sample loss, and contamination. In addition, due to the picogram level of the amount of nucleic acids used, heavy amplification is often needed during sample preparation of single-cell sequencing, resulting in the uneven coverage, noise, and inaccurate quantification of sequencing data. All these unique properties raise challenges in and thus high demands for computational methods that specifically fit single-cell sequencing data. We here comprehensively survey the current strategies and challenges for multiple single-cell sequencing, including single-cell transcriptome, genome, and epigenome, beginning with a brief introduction to multiple sequencing techniques for single cells.

A Bioinspired Mineral Hydrogel as a Self-Healable, Mechanically Adaptable Ionic Skin for Highly Sensitive Pressure Sensing.

PubMed

Lei, Zhouyue; Wang, Quankang; Sun, Shengtong; Zhu, Wencheng; Wu, Peiyi

2017-06-01

In the past two decades, artificial skin-like materials have received increasing research interests for their broad applications in artificial intelligence, wearable devices, and soft robotics. However, profound challenges remain in terms of imitating human skin because of its unique combination of mechanical and sensory properties. In this work, a bioinspired mineral hydrogel is developed to fabricate a novel type of mechanically adaptable ionic skin sensor. Due to its unique viscoelastic properties, the hydrogel-based capacitive sensor is compliant, self-healable, and can sense subtle pressure changes, such as a gentle finger touch, human motion, or even small water droplets. It might not only show great potential in applications such as artificial intelligence, human/machine interactions, personal healthcare, and wearable devices, but also promote the development of next-generation mechanically adaptable intelligent skin-like devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Findings and Recommendations from the NIST Workshop on Alternative Fuels and Materials: Biocorrosion

PubMed Central

Mansfield, Elisabeth; Sowards, Jeffrey W.; Crookes-Goodson, Wendy J.

2015-01-01

In 2013, the Applied Chemicals and Materials Division of the National Institute of Standards and Technology (NIST) hosted a workshop to identify and prioritize research needs in the area of biocorrosion. Materials used to store and distribute alternative fuels have experienced an increase in corrosion due to the unique conditions caused by the presence of microbes and the chemistry of biofuels and biofuel precursors. Participants in this workshop, including experts from the microbiological, fuel, and materials communities, delved into the unique materials and chemical challenges that occur with production, transport, and storage of alternative fuels. Discussions focused on specific problems including: a) the changing composition of “drop-in” fuels and the impact of that composition on materials; b) the influence of microbial populations on corrosion and fuel quality; and c) state-of-the-art measurement technologies for monitoring material degradation and biofilm formation. PMID:26958436

Utilization of targeted near-infrared molecular imaging to improve pulmonary metastasectomy of osteosarcomas

NASA Astrophysics Data System (ADS)

Predina, Jarrod D.; Newton, Andrew; Deshpande, Charuhas; Low, Philip; Singhal, Sunil

2018-01-01

Pulmonary metastasectomy for osteosarcoma provides a select group of patients an opportunity for long-term survival and possible cure. Unfortunately, a complete metastasectomy is challenging due an inability to accurately identify lesions that lay below the threshold of preoperative imaging or intraoperative visual and tactile inspection. Growing evidence suggests that osteosarcomas express a number of unique molecular markers, including the folate receptor alpha. In this case report, we describe the application of a folate receptor-targeted, near-infrared optical contrast agent (OTL38) to improve osteosarcoma localization during minimally invasive pulmonary resection. In addition to localizing preoperatively identified lesions, this technology helped identify additional disease that was undetected on preoperative imaging or with traditional intraoperative techniques. This report marks the first successful utilization of a molecular imaging probe useful for osteosarcomas. This technology may provide a unique approach to improve pulmonary metastasectomy of osteosarcomas.

Oman's coral reefs: A unique ecosystem challenged by natural and man-related stresses and in need of conservation.

PubMed

Burt, J A; Coles, S; van Lavieren, H; Taylor, O; Looker, E; Samimi-Namin, K

2016-04-30

Oman contains diverse and abundant reef coral communities that extend along a coast that borders three environmentally distinct water bodies, with corals existing under unique and often stressful environmental conditions. In recent years Oman's reefs have undergone considerable change due to recurrent predatory starfish outbreaks, cyclone damage, harmful algal blooms, and other stressors. In this review we summarize current knowledge of the biology and status of corals in Oman, particularly in light of recent stressors and projected future threats, and examine current reef management practices. Oman's coral communities occur in marginal environmental conditions for reefs, and hence are quite vulnerable to anthropogenic effects. We recommend a focus on developing conservation-oriented coral research to guide proactive management and expansion of the number and size of designated protected areas in Oman, particularly those associated with critical coral habitat. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Overview of Engineering Design and Analysis at the NASA John C. Stennis Space Center

NASA Technical Reports Server (NTRS)

Ryan, Harry; Congiardo, Jared; Junell, Justin; Kirkpatrick, Richard

2007-01-01

A wide range of rocket propulsion test work occurs at the NASA John C. Stennis Space Center (SSC) including full-scale engine test activities at test facilities A-1, A-2, B-1 and B-2 as well as combustion device research and development activities at the E-Complex (E-1, E-2, E-3 and E-4) test facilities. The propulsion test engineer at NASA SSC faces many challenges associated with designing and operating a test facility due to the extreme operating conditions (e.g., cryogenic temperatures, high pressures) of the various system components and the uniqueness of many of the components and systems. The purpose of this paper is to briefly describe the NASA SSC Engineering Science Directorate s design and analysis processes, experience, and modeling techniques that are used to design and support the operation of unique rocket propulsion test facilities.

Findings and Recommendations from the NIST Workshop on Alternative Fuels and Materials: Biocorrosion.

PubMed

Mansfield, Elisabeth; Sowards, Jeffrey W; Crookes-Goodson, Wendy J

2015-01-01

In 2013, the Applied Chemicals and Materials Division of the National Institute of Standards and Technology (NIST) hosted a workshop to identify and prioritize research needs in the area of biocorrosion. Materials used to store and distribute alternative fuels have experienced an increase in corrosion due to the unique conditions caused by the presence of microbes and the chemistry of biofuels and biofuel precursors. Participants in this workshop, including experts from the microbiological, fuel, and materials communities, delved into the unique materials and chemical challenges that occur with production, transport, and storage of alternative fuels. Discussions focused on specific problems including: a) the changing composition of "drop-in" fuels and the impact of that composition on materials; b) the influence of microbial populations on corrosion and fuel quality; and c) state-of-the-art measurement technologies for monitoring material degradation and biofilm formation.

Extended-Range Forecasts at Climate Prediction Center: Current Status and Future Plans

NASA Astrophysics Data System (ADS)

Kumar, A.

2016-12-01

Motivated by a user need to provide forecast information on extended-range time-scales (i.e., weeks 2-4), in recent years Climate Prediction Center (CPC) has made considerable efforts towards developing and testing the feasibility for developing the required forecasts. The forecasts targeting this particular time-scale face a unique challenge in that while the forecast skill due to atmospheric initial conditions is small (because of rapid decay in the memory associated with the atmospheric initial conditions), short time averages for which forecasts are made do not benefit from skill associated with anomalous boundary conditions either. Despite these challenges, CPC has embarked on providing an experimental outlook for weeks 3-4 average. The talk will summarize the current status of CPC's current suite of extended-range forecast products, and further, will discuss some future plans.

Providing health services for children with special health care needs on out-of-state field trips.

PubMed

Erwin, Karen; Clark, Saudi; Mercer, Sharon Eli

2014-03-01

An increasing number of children attend school with special health care needs. Title II of the Americans with Disabilities Act (ADA) requires all school-sponsored activities to be easily accessible to all students. School-sponsored field trips enhance students' education, and students who require health services may not be excluded. For students with special health care needs, fully participating in the field trip experience presents unique challenges. These challenges are further complicated by out-of-state field trips due to variances in nurse practice acts, variances in delegation regulations, and most recently, state-by-state participation or nonparticipation in the Nurse Licensure Compact. Review of state laws, regulations, and nursing scope of practice for school health services is critical when planning and problem solving for students requiring health services on out-of-state field trips.

ATLAS, CMS and new challenges for public communication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taylor, Lucas; Barney, David; Goldfarb, Steven

On 30 March 2010 the first high-energy collisions brought the LHC experiments into the era of research and discovery. Millions of viewers worldwide tuned in to the webcasts and followed the news via Web 2.0 tools, such as blogs, Twitter, and Facebook, with 205,000 unique visitors to CERN's Web site. Media coverage at the experiments and in institutes all over the world yielded more than 2,200 news items including 800 TV broadcasts. We describe the new multimedia communications challenges, due to the massive public interest in the LHC programme, and the corresponding responses of the ATLAS and CMS experiments, inmore » the areas of Web 2.0 tools, multimedia, webcasting, videoconferencing, and collaborative tools. We discuss the strategic convergence of the two experiments' communications services, information systems and public database of outreach material.« less

ATLAS, CMS and New Challenges for Public Communication

NASA Astrophysics Data System (ADS)

Taylor, Lucas; Barney, David; Goldfarb, Steven

2011-12-01

On 30 March 2010 the first high-energy collisions brought the LHC experiments into the era of research and discovery. Millions of viewers worldwide tuned in to the webcasts and followed the news via Web 2.0 tools, such as blogs, Twitter, and Facebook, with 205,000 unique visitors to CERN's Web site. Media coverage at the experiments and in institutes all over the world yielded more than 2,200 news items including 800 TV broadcasts. We describe the new multimedia communications challenges, due to the massive public interest in the LHC programme, and the corresponding responses of the ATLAS and CMS experiments, in the areas of Web 2.0 tools, multimedia, webcasting, videoconferencing, and collaborative tools. We discuss the strategic convergence of the two experiments' communications services, information systems and public database of outreach material.

Mesoporous silica nanoparticles for stimuli-responsive controlled drug delivery: advances, challenges, and outlook

PubMed Central

Song, Yuanhui; Li, Yihong; Xu, Qien; Liu, Zhe

2017-01-01

With the development of nanotechnology, the application of nanomaterials in the field of drug delivery has attracted much attention in the past decades. Mesoporous silica nanoparticles as promising drug nanocarriers have become a new area of interest in recent years due to their unique properties and capabilities to efficiently entrap cargo molecules. This review describes the latest advances on the application of mesoporous silica nanoparticles in drug delivery. In particular, we focus on the stimuli-responsive controlled release systems that are able to respond to intracellular environmental changes, such as pH, ATP, GSH, enzyme, glucose, and H2O2. Moreover, drug delivery induced by exogenous stimuli including temperature, light, magnetic field, ultrasound, and electricity is also summarized. These advanced technologies demonstrate current challenges, and provide a bright future for precision diagnosis and treatment. PMID:28053526

Mesoporous silica nanoparticles for stimuli-responsive controlled drug delivery: advances, challenges, and outlook.

PubMed

Song, Yuanhui; Li, Yihong; Xu, Qien; Liu, Zhe

With the development of nanotechnology, the application of nanomaterials in the field of drug delivery has attracted much attention in the past decades. Mesoporous silica nanoparticles as promising drug nanocarriers have become a new area of interest in recent years due to their unique properties and capabilities to efficiently entrap cargo molecules. This review describes the latest advances on the application of mesoporous silica nanoparticles in drug delivery. In particular, we focus on the stimuli-responsive controlled release systems that are able to respond to intracellular environmental changes, such as pH, ATP, GSH, enzyme, glucose, and H 2 O 2 . Moreover, drug delivery induced by exogenous stimuli including temperature, light, magnetic field, ultrasound, and electricity is also summarized. These advanced technologies demonstrate current challenges, and provide a bright future for precision diagnosis and treatment.

Biomimetic chemical sensors using bioengineered olfactory and taste cells.

PubMed

Du, Liping; Zou, Ling; Zhao, Luhang; Wang, Ping; Wu, Chunsheng

2014-01-01

Biological olfactory and taste systems are natural chemical sensing systems with unique performances for the detection of environmental chemical signals. With the advances in olfactory and taste transduction mechanisms, biomimetic chemical sensors have achieved significant progress due to their promising prospects and potential applications. Biomimetic chemical sensors exploit the unique capability of biological functional components for chemical sensing, which are often sourced from sensing units of biological olfactory or taste systems at the tissue level, cellular level, or molecular level. Specifically, at the cellular level, there are mainly two categories of cells have been employed for the development of biomimetic chemical sensors, which are natural cells and bioengineered cells, respectively. Natural cells are directly isolated from biological olfactory and taste systems, which are convenient to achieve. However, natural cells often suffer from the undefined sensing properties and limited amount of identical cells. On the other hand, bioengineered cells have shown decisive advantages to be applied in the development of biomimetic chemical sensors due to the powerful biotechnology for the reconstruction of the cell sensing properties. Here, we briefly summarized the most recent advances of biomimetic chemical sensors using bioengineered olfactory and taste cells. The development challenges and future trends are discussed as well.

An agenda-based routing protocol in delay tolerant mobile sensor networks.

PubMed

Wang, Xiao-Min; Zhu, Jin-Qi; Liu, Ming; Gong, Hai-Gang

2010-01-01

Routing in delay tolerant mobile sensor networks (DTMSNs) is challenging due to the networks' intermittent connectivity. Most existing routing protocols for DTMSNs use simplistic random mobility models for algorithm design and performance evaluation. In the real world, however, due to the unique characteristics of human mobility, currently existing random mobility models may not work well in environments where mobile sensor units are carried (such as DTMSNs). Taking a person's social activities into consideration, in this paper, we seek to improve DTMSN routing in terms of social structure and propose an agenda based routing protocol (ARP). In ARP, humans are classified based on their agendas and data transmission is made according to sensor nodes' transmission rankings. The effectiveness of ARP is demonstrated through comprehensive simulation studies.

The space shuttle ascent vehicle aerodynamic challenges configuration design and data base development

NASA Technical Reports Server (NTRS)

Dill, C. C.; Young, J. C.; Roberts, B. B.; Craig, M. K.; Hamilton, J. T.; Boyle, W. W.

1985-01-01

The phase B Space Shuttle systems definition studies resulted in a generic configuration consisting of a delta wing orbiter, and two solid rocket boosters (SRB) attached to an external fuel tank (ET). The initial challenge facing the aerodynamic community was aerodynamically optimizing, within limits, this configuration. As the Shuttle program developed and the sensitivities of the vehicle to aerodynamics were better understood the requirements of the aerodynamic data base grew. Adequately characterizing the vehicle to support the various design studies exploded the size of the data base to proportions that created a data modeling/management challenge for the aerodynamicist. The ascent aerodynamic data base originated primarily from wind tunnel test results. The complexity of the configuration rendered conventional analytic methods of little use. Initial wind tunnel tests provided results which included undesirable effects from model support tructure, inadequate element proximity, and inadequate plume simulation. The challenge to improve the quality of test results by determining the extent of these undesirable effects and subsequently develop testing techniques to eliminate them was imposed on the aerodynamic community. The challenges to the ascent aerodynamics community documented are unique due to the aerodynamic complexity of the Shuttle launch. Never before was such a complex vehicle aerodynamically characterized. The challenges were met with innovative engineering analyses/methodology development and wind tunnel testing techniques.

NASA Space Rocket Logistics Challenges

NASA Technical Reports Server (NTRS)

Neeley, James R.; Jones, James V.; Watson, Michael D.; Bramon, Christopher J.; Inman, Sharon K.; Tuttle, Loraine

2014-01-01

The Space Launch System (SLS) is the new NASA heavy lift launch vehicle and is scheduled for its first mission in 2017. The goal of the first mission, which will be uncrewed, is to demonstrate the integrated system performance of the SLS rocket and spacecraft before a crewed flight in 2021. SLS has many of the same logistics challenges as any other large scale program. Common logistics concerns for SLS include integration of discreet programs geographically separated, multiple prime contractors with distinct and different goals, schedule pressures and funding constraints. However, SLS also faces unique challenges. The new program is a confluence of new hardware and heritage, with heritage hardware constituting seventy-five percent of the program. This unique approach to design makes logistics concerns such as commonality especially problematic. Additionally, a very low manifest rate of one flight every four years makes logistics comparatively expensive. That, along with the SLS architecture being developed using a block upgrade evolutionary approach, exacerbates long-range planning for supportability considerations. These common and unique logistics challenges must be clearly identified and tackled to allow SLS to have a successful program. This paper will address the common and unique challenges facing the SLS programs, along with the analysis and decisions the NASA Logistics engineers are making to mitigate the threats posed by each.

ADHD and Adolescent Athletes

PubMed Central

Nazeer, Ahsan; Mansour, Miriam; Gross, Kathleen A.

2014-01-01

Attention-deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that affects the child and adolescent population. It is characterized by impairment in attention/concentration, hyperactivity, and impulsivity, all of which can impact performance of athletes. ADHD treatment within the athletic population is a unique challenge. The research in this field has been relatively limited. The National Collegiate Athletic Association and International Olympic Committee both regulate the use of psychostimulants for treatment of ADHD due to their performance-enhancing effects. In this article, authors have discussed the screening methods, pharmacological treatment, side effects, and behavioral approaches for the treatment of ADHD in adolescent athletes. PMID:24987666

Management of Herpes Simplex Virus Keratitis in the Pediatric Population.

PubMed

Vadoothker, Saujanya; Andrews, Laura; Jeng, Bennie H; Levin, Moran Roni

2018-05-14

Herpes simplex virus (HSV) keratitis is a highly prevalent and visually-disabling disease in both the pediatric and adult population. While many studies have investigated the treatment of HSV keratitis in adult patients, few have focused on managing this condition in children. Children are at particularly high risk for visual morbidity due to unique challenges in diagnosis and treatment, and the often more aggressive disease course that results in corneal scarring, and subsequently amblyopia. This review presents the pathogenesis and most current recommendations for the medical and surgical management of HSV keratitis in the pediatric population.

Scan direction induced charging dynamics and the application for detection of gate to S/D shorts in logic devices

NASA Astrophysics Data System (ADS)

Lei, Ming; Tian, Qing; Wu, Kevin; Zhao, Yan

2016-03-01

Gate to source/drain (S/D) short is the most common and detrimental failure mechanism for advanced process technology development in Metal-Oxide-Semiconductor-Field-Effect-Transistor (MOSFET) device manufacturing. Especially for sub-1Xnm nodes, MOSFET device is more vulnerable to gate-S/D shorts due to the aggressive scaling. The detection of this kind of electrical short defect is always challenging for in-line electron beam inspection (EBI), especially new shorting mechanisms on atomic scale due to new material/process flow implementation. The second challenge comes from the characterization of the shorts including identification of the exact shorting location. In this paper, we demonstrate unique scan direction induced charging dynamics (SDCD) phenomenon which stems from the transistor level response from EBI scan at post metal contact chemical-mechanical planarization (CMP) layers. We found that SDCD effect is exceptionally useful for gate-S/D short induced voltage contrast (VC) defect detection, especially for identification of shorting locations. The unique SDCD effect signatures of gate-S/D shorts can be used as fingerprint for ground true shorting defect detection. Correlation with other characterization methods on the same defective location from EBI scan shows consistent results from various shorting mechanism. A practical work flow to implement the application of SDCD effect for in-line EBI monitor of critical gate-S/D short defects is also proposed, together with examples of successful application use cases which mostly focus on static random-access memory (SRAM) array regions. Although the capability of gate-S/D short detection as well as expected device response is limited to passing transistors and pull-down transistors due to the design restriction from standard 6-cell SRAM structure, SDCD effect is proven to be very effective for gate-S/D short induced VC defect detection as well as yield learning for advanced technology development.

Emergence of charge density waves and a pseudogap in single-layer TiTe2.

PubMed

Chen, P; Pai, Woei Wu; Chan, Y-H; Takayama, A; Xu, C-Z; Karn, A; Hasegawa, S; Chou, M Y; Mo, S-K; Fedorov, A-V; Chiang, T-C

2017-09-11

Two-dimensional materials constitute a promising platform for developing nanoscale devices and systems. Their physical properties can be very different from those of the corresponding three-dimensional materials because of extreme quantum confinement and dimensional reduction. Here we report a study of TiTe 2 from the single-layer to the bulk limit. Using angle-resolved photoemission spectroscopy and scanning tunneling microscopy and spectroscopy, we observed the emergence of a (2 × 2) charge density wave order in single-layer TiTe 2 with a transition temperature of 92 ± 3 K. Also observed was a pseudogap of about 28 meV at the Fermi level at 4.2 K. Surprisingly, no charge density wave transitions were observed in two-layer and multi-layer TiTe 2 , despite the quasi-two-dimensional nature of the material in the bulk. The unique charge density wave phenomenon in the single layer raises intriguing questions that challenge the prevailing thinking about the mechanisms of charge density wave formation.Due to reduced dimensionality, the properties of 2D materials are often different from their 3D counterparts. Here, the authors identify the emergence of a unique charge density wave (CDW) order in monolayer TiTe 2 that challenges the current understanding of CDW formation.

NordicWelfAir - Understanding the link between Air pollution and Distribution of related Health Impacts and Welfare in the Nordic countries

NASA Astrophysics Data System (ADS)

Brandt, Jørgen

2017-04-01

Air pollution has serious impacts on human health, wellbeing and welfare. The main challenge is to understand how to regulate air pollution in an optimal way both on global and local scales. Linking the detailed information of the spatio-temporal distribution of air pollution levels and the chemical composition of the atmospheric particles with register data for mortality and morbidity, we have a unique opportunity in the Nordic countries to gain new understanding of the various health impacts from different kinds of air pollution from different kind of sources. This will provide the basic understanding needed for policy making of strategies to optimally reduce the air pollution challenge and to assess the related impacts on the distribution of health impacts and related societal costs and welfare. The large interdisciplinary NordicWelfAir project (http://nordicwelfair.au.dk), funded by NordForsk, will take advantage of the unique Nordic data. The results from the project will be used in both a Nordic as well as global perspective to improve the health and welfare by finding the optimal solutions to societal and public health challenges from air pollution through high-quality research. The results from the research in this project have the potential to act as new international standards in our understanding of health impacts from air pollution for different population groups due to the possibility to integrate the unique data and knowledge of air pollution, register, health, socio-economics, and welfare research in the Nordic countries in a highly interdisciplinary project. The study will provide a Nordic contribution to international research on the topics of environmental equality and justice within the area of air quality related risks, amenities and wellbeing. Acknowledgements This project is funded by NordForsk under the Nordic Programme on Health and Welfare. Project #75007: Understanding the link between air pollution and distribution of related health impacts and welfare in the Nordic countries (http://NordicWelfAir.au.dk).

YogaHome: teaching and research challenges in a yoga program with homeless adults.

PubMed

Davis-Berman, Jennifer; Farkas, Jean

2012-01-01

YogaHome is a therapeutic yoga program for homeless women. Developing and refining YogaHome provided a unique opportunity to explore the process of teaching yoga to women faced with the physical and emotional stress of living in a homeless shelter. Unique teaching and research challenges are presented and recommendations for future programs are discussed.

Brain Metastasis: Unique Challenges and Open Opportunities

PubMed Central

Lowery, Frank J.; Yu, Dihua

2016-01-01

The metastasis of cancer to the central nervous system (CNS) remains a devastating clinical reality, carrying an estimated survival time of less than one year in spite of recent therapeutic breakthroughs for other disease contexts. Advances in brain metastasis research are hindered by a number of reasons, including its complicated nature and the difficulty of modeling metastatic cancer growth in the unique brain microenvironment. In this review, we will discuss the clinical challenge, and compare the values and limitations of the available models for brain metastasis research. Additionally, we will specifically address current knowledge on how brain metastases take advantage of the unique brain environment to benefit their own growth. Finally, we will explore the distinctive metabolic and nutrient characteristics of the brain; how these paradoxically represent barriers to establishment of brain metastasis, but also provide ample supplies for metastatic cells’ growth in the brain. We envision that multi-disciplinary innovative approaches will open opportunities for the field to make breakthroughs in tackling unique challenges of brain metastasis. PMID:27939792

Legal Aspects of Sleep Medicine in the 21st Century.

PubMed

Venkateshiah, Saiprakash B; Hoque, Romy; Collop, Nancy A

2018-05-08

Multiple manifestations of sleep disorders may interact with the law making it important to increase awareness of such interactions among clinicians. Patients with excessive sleepiness may have civil (and in some states criminal) liability if they fall asleep while driving and cause a motor vehicle accident. Employers may be held vicariously liable due to the actions of sleepy employees. Hence awareness of causes of excessive sleepiness such as sleep deprivation and OSA is increasing among trucking, railroad, and other safety sensitive occupations. Interestingly, litigation related to perioperative complications due to Obstructive Sleep Apnea (OSA) is more frequent than non-operative issues such as a failure to diagnose OSA. Parasomnia associated sleep-related violence (SRV) represents a challenge to clinicians, as they may be asked to consider parasomnia as a possible contributing, mitigating, or exculpatory factor in criminal proceedings. Clinicians should also familiarize with the legal and regulatory aspects of running an independent sleep laboratory. Sleep telemedicine practice using 21 st century technology has opened novel and unique challenges to existing laws. In this review, we shall cover the most common interactions between sleep disorders and the law including the challenges of excessive sleepiness and driving; other legal issues involving patients with obstructive sleep apnea (OSA); and the liabilities associated with parasomnia disorder. We shall also cover some practical legal aspects involving independent sleep laboratories and the field of sleep telemedicine. Published by Elsevier Inc.

Bringing nanomedicines to market: regulatory challenges, opportunities, and uncertainties.

PubMed

Nijhara, Ruchika; Balakrishnan, Krishna

2006-06-01

Scientists and entrepreneurs who contemplate developing nanomedicine products face several unique challenges in addition to many of the traditional hurdles of product development. In this review we analyze the major physicochemical, biologic and functional characteristics of several nanomedicine products on the market and explore the question of what made them unique. What made them successful? We also focus on the regulatory challenges faced by nanomedicine product developers. Based on these analyses, we propose the factors that are most likely to contribute to the success of nanomedicine products.

Stability of Chitosan—A Challenge for Pharmaceutical and Biomedical Applications

PubMed Central

Szymańska, Emilia; Winnicka, Katarzyna

2015-01-01

Chitosan—one of the natural multifunctional polymers—due to its unique and versatile biological properties is regarded as a useful compound in medical and pharmaceutical technology. Recently, considerable research effort has been made in order to develop safe and efficient chitosan products. However, the problem of poor stability of chitosan-based systems restricts its practical applicability; thus, it has become a great challenge to establish sufficient shelf-life for chitosan formulations. Improved stability can be assessed by controlling the environmental factors, manipulating processing conditions (e.g., temperature), introducing a proper stabilizing compound, developing chitosan blends with another polymer, or modifying the chitosan structure using chemical or ionic agents. This review covers the influence of internal, environmental, and processing factors on the long-term stability of chitosan products. The aim of this paper is also to highlight the latest developments which enable the physicochemical properties of chitosan-based applications to be preserved upon storage. PMID:25837983

Biodegradable nanoparticles for intracellular delivery of antimicrobial agents.

PubMed

Xie, Shuyu; Tao, Yanfei; Pan, Yuanhu; Qu, Wei; Cheng, Guyue; Huang, Lingli; Chen, Dongmei; Wang, Xu; Liu, Zhenli; Yuan, Zonghui

2014-08-10

Biodegradable nanoparticles have emerged as a promising strategy for ferrying antimicrobial agents into specific cells due to their unique properties. This review discusses the current progress and challenges of biodegradable nanoparticles for intracellular antimicrobial delivery to understand design principles for the development of ideal nanocarriers. The intracellular delivery performances of biodegradable nanoparticles for diverse antimicrobial agents are first summarized. Second, the cellular internalization and intracellular trafficking, degradation and release kinetics of nanoparticles as well as their relation with intracellular delivery of encapsulated antimicrobial agents are provided. Third, the influences of nanoparticle properties on the cellular internalization and intracellular fate of nanoparticles and their payload antimicrobial agents are discussed. Finally, the challenges and perspectives of nanoparticles for intracellular delivery of antimicrobial agents are addressed. The review will be helpful to the scientists who are interested in searching for more efficient nanosystem strategies for intracellular delivery of antimicrobial agents. Copyright © 2014 Elsevier B.V. All rights reserved.

Platinum replica electron microscopy: Imaging the cytoskeleton globally and locally.

PubMed

Svitkina, Tatyana M

2017-05-01

Structural studies reveal how smaller components of a system work together as a whole. However, combining high resolution of details with full coverage of the whole is challenging. In cell biology, light microscopy can image many cells in their entirety, but at a lower resolution, whereas electron microscopy affords very high resolution, but usually at the expense of the sample size and coverage. Structural analyses of the cytoskeleton are especially demanding, because cytoskeletal networks are unresolvable by light microscopy due to their density and intricacy, whereas their proper preservation is a challenge for electron microscopy. Platinum replica electron microscopy can uniquely bridge the gap between the "comfort zones" of light and electron microscopy by allowing high resolution imaging of the cytoskeleton throughout the entire cell and in many cells in the population. This review describes the principles and applications of platinum replica electron microscopy for studies of the cytoskeleton. Copyright © 2017 Elsevier Ltd. All rights reserved.

Composites of Polymer Hydrogels and Nanoparticulate Systems for Biomedical and Pharmaceutical Applications

PubMed Central

Zhao, Fuli; Yao, Dan; Guo, Ruiwei; Deng, Liandong; Dong, Anjie; Zhang, Jianhua

2015-01-01

Due to their unique structures and properties, three-dimensional hydrogels and nanostructured particles have been widely studied and shown a very high potential for medical, therapeutic and diagnostic applications. However, hydrogels and nanoparticulate systems have respective disadvantages that limit their widespread applications. Recently, the incorporation of nanostructured fillers into hydrogels has been developed as an innovative means for the creation of novel materials with diverse functionality in order to meet new challenges. In this review, the fundamentals of hydrogels and nanoparticles (NPs) were briefly discussed, and then we comprehensively summarized recent advances in the design, synthesis, functionalization and application of nanocomposite hydrogels with enhanced mechanical, biological and physicochemical properties. Moreover, the current challenges and future opportunities for the use of these promising materials in the biomedical sector, especially the nanocomposite hydrogels produced from hydrogels and polymeric NPs, are discussed. PMID:28347111

Quantitative High-throughput Luciferase Screening in Identifying CAR Modulators

PubMed Central

Lynch, Caitlin; Zhao, Jinghua; Wang, Hongbing; Xia, Menghang

2017-01-01

Summary The constitutive androstane receptor (CAR, NR1I3) is responsible for the transcription of multiple drug metabolizing enzymes and transporters. There are two possible methods of activation for CAR, direct ligand binding and a ligand-independent method, which makes this a unique nuclear receptor. Both of these mechanisms require translocation of CAR from the cytoplasm into the nucleus. Interestingly, CAR is constitutively active in immortalized cell lines due to the basal nuclear location of this receptor. This creates an important challenge in most in vitro assay models because immortalized cells cannot be used without inhibiting the basal activity. In this book chapter, we go into detail of how to perform quantitative high-throughput screens to identify hCAR1 modulators through the employment of a double stable cell line. Using this line, we are able to identify activators, as well as deactivators, of the challenging nuclear receptor, CAR. PMID:27518621

Quantitative High-Throughput Luciferase Screening in Identifying CAR Modulators.

PubMed

Lynch, Caitlin; Zhao, Jinghua; Wang, Hongbing; Xia, Menghang

2016-01-01

The constitutive androstane receptor (CAR, NR1I3) is responsible for the transcription of multiple drug metabolizing enzymes and transporters. There are two possible methods of activation for CAR, direct ligand binding and a ligand-independent method, which makes this a unique nuclear receptor. Both of these mechanisms require translocation of CAR from the cytoplasm into the nucleus. Interestingly, CAR is constitutively active in immortalized cell lines due to the basal nuclear location of this receptor. This creates an important challenge in most in vitro assay models because immortalized cells cannot be used without inhibiting the high basal activity. In this book chapter, we go into detail of how to perform quantitative high-throughput screens to identify hCAR1 modulators through the employment of a double stable cell line. Using this line, we are able to identify activators, as well as deactivators, of the challenging nuclear receptor, CAR.

Dynamic Tunneling Junctions at the Atomic Intersection of Two Twisted Graphene Edges.

PubMed

Bellunato, Amedeo; Vrbica, Sasha D; Sabater, Carlos; de Vos, Erik W; Fermin, Remko; Kanneworff, Kirsten N; Galli, Federica; van Ruitenbeek, Jan M; Schneider, Grégory F

2018-04-11

The investigation of the transport properties of single molecules by flowing tunneling currents across extremely narrow gaps is relevant for challenges as diverse as the development of molecular electronics and sequencing of DNA. The achievement of well-defined electrode architectures remains a technical challenge, especially due to the necessity of high precision fabrication processes and the chemical instability of most bulk metals. Here, we illustrate a continuously adjustable tunneling junction between the edges of two twisted graphene sheets. The unique property of the graphene electrodes is that the sheets are rigidly supported all the way to the atomic edge. By analyzing the tunneling current characteristics, we also demonstrate that the spacing across the gap junction can be controllably adjusted. Finally, we demonstrate the transition from the tunneling regime to contact and the formation of an atomic-sized junction between the two edges of graphene.

Platinum Replica Electron Microscopy: Imaging the Cytoskeleton Globally and Locally

PubMed Central

SVITKINA, Tatyana M.

2017-01-01

Structural studies reveal how smaller components of a system work together as a whole. However, combining high resolution of details with full coverage of the whole is challenging. In cell biology, light microscopy can image many cells in their entirety, but at a lower resolution, whereas electron microscopy affords very high resolution, but usually at the expense of the sample size and coverage. Structural analyses of the cytoskeleton are especially demanding, because cytoskeletal networks are unresolvable by light microscopy due to their density and intricacy, whereas their proper preservation is a challenge for electron microscopy. Platinum replica electron microscopy can uniquely bridge the gap between the “comfort zones” of light and electron microscopy by allowing high resolution imaging of the cytoskeleton throughout the entire cell and in many cells in the population. This review describes the principles and applications of platinum replica electron microscopy for studies of the cytoskeleton. PMID:28323208

Transition Metal Nitrides for Electrocatalytic Energy Conversion: Opportunities and Challenges.

PubMed

Xie, Junfeng; Xie, Yi

2016-03-07

Electrocatalytic energy conversion has been considered as one of the most efficient and promising pathways for realizing energy storage and energy utilization in modern society. To improve electrocatalytic reactions, specific catalysts are needed to lower the overpotential. In the search for efficient alternatives to noble metal catalysts, transition metal nitrides have attracted considerable interest due to their high catalytic activity and unique electronic structure. Over the past few decades, numerous nitride-based catalysts have been explored with respect to their ability to drive various electrocatalytic reactions, such as the hydrogen evolution reaction and the oxygen evolution reaction to achieve water splitting and the oxygen reduction reaction coupled with the methanol oxidation reaction to construct fuel cells or rechargeable Li-O2 batteries. This Minireview provides a brief overview of recent progress on electrocatalysts based on transition metal nitrides, and outlines the current challenges and future opportunities. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New solution decomposition and minimization schemes for Poisson-Boltzmann equation in calculation of biomolecular electrostatics

NASA Astrophysics Data System (ADS)

Xie, Dexuan

2014-10-01

The Poisson-Boltzmann equation (PBE) is one widely-used implicit solvent continuum model in the calculation of electrostatic potential energy for biomolecules in ionic solvent, but its numerical solution remains a challenge due to its strong singularity and nonlinearity caused by its singular distribution source terms and exponential nonlinear terms. To effectively deal with such a challenge, in this paper, new solution decomposition and minimization schemes are proposed, together with a new PBE analysis on solution existence and uniqueness. Moreover, a PBE finite element program package is developed in Python based on the FEniCS program library and GAMer, a molecular surface and volumetric mesh generation program package. Numerical tests on proteins and a nonlinear Born ball model with an analytical solution validate the new solution decomposition and minimization schemes, and demonstrate the effectiveness and efficiency of the new PBE finite element program package.

Cytochrome P450 isozyme protein verified in the skin of southern hemisphere humpback whales (Megaptera novaeangliae): implications for biochemical biomarker assessment.

PubMed

Waugh, Courtney A; Huston, Wilhelmina M; Noad, Michael J; Bengtson Nash, Susan

2011-04-01

Large mysticete whales represent a unique challenge for chemical risk assessment. Few epidemiological investigations are possible due to the low incidence of adult stranding events. Similarly their often extreme life-history adaptations of prolonged migration and fasting challenge exposure assumptions. Molecular biomarkers offer the potential to complement information yielded through tissue chemical analysis, as well as providing evidence of a molecular response to chemical exposure. In this study we confirm the presence of cytochrome P450 reductase (CPR) and cytochrome P450 isoenzyme 1A1 (CYP1A1) in epidermal tissue of southern hemisphere humpback whales (Megaptera novaeangliae). The detection of CYP1A1 in the integument of the humpback whale affords the opportunity for further quantitative non-destructive investigations of enzyme activity as a function of chemical stress. Copyright © 2011 Elsevier Ltd. All rights reserved.

Overpumping leads to California groundwater arsenic threat.

PubMed

Smith, Ryan; Knight, Rosemary; Fendorf, Scott

2018-06-05

Water resources are being challenged to meet domestic, agricultural, and industrial needs. To complement finite surface water supplies that are being stressed by changes in precipitation and increased demand, groundwater is increasingly being used. Sustaining groundwater use requires considering both water quantity and quality. A unique challenge for groundwater use, as compared with surface water, is the presence of naturally occurring contaminants within aquifer sediments, which can enter the water supply. Here we find that recent groundwater pumping, observed through land subsidence, results in an increase in aquifer arsenic concentrations in the San Joaquin Valley of California. By comparison, historic groundwater pumping shows no link to current groundwater arsenic concentrations. Our results support the premise that arsenic can reside within pore water of clay strata within aquifers and is released due to overpumping. We provide a quantitative model for using subsidence as an indicator of arsenic concentrations correlated with groundwater pumping.

Adapting to the health impacts of climate change in a sustainable manner.

PubMed

Hoy, Damian; Roth, Adam; Lepers, Christelle; Durham, Jo; Bell, Johann; Durand, Alexis; Lal, Padma Narsey; Souares, Yvan

2014-12-11

The climate is changing and this poses significant threats to human health. Climate change is one of the greatest challenges facing Pacific Island countries and territories due to their unique geophysical features, and their social, economic and cultural characteristics. The Pacific region also faces challenges with widely dispersed populations, limited resources and fragmented health systems. Over the past few years, there has been a substantial increase in international aid for health activities aimed at adapting to the threats of climate change. This funding needs to be used strategically to ensure an effective approach to reducing the health risk from climate change. Respecting the principles of development effectiveness will result in more effective and sustainable adaptation, in particular, 1) processes should be owned and driven by local communities, 2) investments should be aligned with existing national priorities and policies, and 3) existing systems must not be ignored, but rather expanded upon and reinforced.

Dynamic Tunneling Junctions at the Atomic Intersection of Two Twisted Graphene Edges

PubMed Central

2018-01-01

The investigation of the transport properties of single molecules by flowing tunneling currents across extremely narrow gaps is relevant for challenges as diverse as the development of molecular electronics and sequencing of DNA. The achievement of well-defined electrode architectures remains a technical challenge, especially due to the necessity of high precision fabrication processes and the chemical instability of most bulk metals. Here, we illustrate a continuously adjustable tunneling junction between the edges of two twisted graphene sheets. The unique property of the graphene electrodes is that the sheets are rigidly supported all the way to the atomic edge. By analyzing the tunneling current characteristics, we also demonstrate that the spacing across the gap junction can be controllably adjusted. Finally, we demonstrate the transition from the tunneling regime to contact and the formation of an atomic-sized junction between the two edges of graphene. PMID:29513997

Quality challenges associated with microbial-based cleaning products from the Industry Perspective.

PubMed

Teasdale, Steve M; Kademi, Ali

2018-06-01

Microbial-based cleaning products (MBCPs) continue to gain popularity in the market as environmentally friendly cleaners. The majority of these products contain spores of various Bacillus species. Although the microorganisms used in MBCPs are subject to regulation in Canada under the Canadian Environmental Protection Act, the products themselves are not. Unlike other types of microbial products such as probiotics and biopesticides, the use, manufacture and quality parameters of MBCPs in Canada and other countries are poorly defined and not specifically subject to any required standards. Due to their complexity and nature, these products feature unique quality challenges. We noted the existing MBCPs we analyzed vary vastly in quality; external microbial contaminants, viability of the spores and the biocompatibility of the ingredients are issues that greatly affect product quality. A proper taxonomic identification of the bacterial species used also seems to be a major challenge for a number of manufacturers. A good understanding of the mechanisms governing these quality challenges and the adoption of good practices for the cultivation, harvesting, formulation, and manufacture of these types of products are essential for achieving high-quality performance standards. Copyright © 2017 Elsevier Ltd. All rights reserved.

Overview of NASA's Thermal Control System Development for Exploration Project

NASA Technical Reports Server (NTRS)

Stephan, Ryan A.

2010-01-01

NASA's Constellation Program includes the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, are manned space vehicles while the third element is broader and includes several sub-elements including Rovers and a Lunar Habitat. The upcoming planned missions involving these systems and vehicles include several risks and design challenges. Due to the unique thermal environment, many of these risks and challenges are associated with the vehicles' thermal control system. NASA's Exploration Systems Mission Directorate (ESMD) includes the Exploration Technology Development Program (ETDP). ETDP consists of several technology development projects. The project chartered with mitigating the aforementioned risks and design challenges is the Thermal Control System Development for Exploration Project. The risks and design challenges are addressed through a rigorous technology development process that culminates with an integrated thermal control system test. The resulting hardware typically has a Technology Readiness Level (TRL) of six. This paper summarizes the development efforts being performed by the technology development project. The development efforts involve heat acquisition and heat rejection hardware including radiators, heat exchangers, and evaporators. The project has also been developing advanced phase change material heat sinks and performing assessments for thermal control system fluids.

Achieving the four dimensions of food security for resettled refugees in Australia: A systematic review.

PubMed

Lawlis, Tanya; Islam, Wasima; Upton, Penney

2018-04-01

Food security is defined by four dimensions: food availability, access, utilisation and stability. Resettled refugees face unique struggles securing these dimensions and, thus, food security when moving to a new country. This systematic review aimed to identify the challenges Australian refugees experience in achieving the four dimensions of food security. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed; the SPIDER tool was used to determine eligibility criteria. Three databases were searched using terms relating to food in/security and refugees from 2000 to 20 May 2017. Seven articles were retained for analysis. Studies were categorised against the four dimensions, with four studies identifying challenges against all dimensions. Challenges contributing to high levels of food insecurity in each dimension included: availability and cost of traditional foods, difficulty in accessing preferred food outlets, limited food knowledge and preparation skills and food stability due to low income and social support. Food insecurity adversely impacts refugee health and integration. Methodical research framed by the four dimensions of food security is imperative to address challenges to securing food security in refugee groups and assisting in the development of sustainable interventions. © 2017 Dietitians Association of Australia.

Current applications and future prospects of nanomaterials in tumor therapy.

PubMed

Huang, Yu; Fan, Chao-Qiang; Dong, Hui; Wang, Su-Min; Yang, Xiao-Chao; Yang, Shi-Ming

2017-01-01

Tumors are one of the most serious human diseases and cause numerous global deaths per year. In spite of many strategies applied in tumor therapy, such as radiation therapy, chemotherapy, surgery, and a combination of these treatments, tumors are still the foremost killer worldwide among human diseases, due to their specific limitations, such as multidrug resistance and side effects. Therefore, it is urgent and necessary to develop new strategies for tumor therapy. Recently, the fast development of nanoscience has paved the way for designing new strategies to treat tumors. Nanomaterials have shown great potential in tumor therapy, due to their unique properties, including passive targeting, hyperthermia effects, and tumor-specific inhibition. This review summarizes the recent progress using the innate antitumor properties of metallic and nonmetallic nanomaterials to treat tumors, and related challenges and prospects are discussed.

The dairy industry: a brief description of production practices, trends, and farm characteristics around the world.

PubMed

Douphrate, David I; Hagevoort, G Robert; Nonnenmann, Matthew W; Lunner Kolstrup, Christina; Reynolds, Stephen J; Jakob, Martina; Kinsel, Mark

2013-01-01

The global dairy industry is composed of a multitude of countries with unique production practices and consumer markets. The global average number of cows per farm is about 1-2 cows; however, as a farm business model transitions from sustenance to market production, the average herd size, and subsequent labor force increases. Dairy production is unique as an agricultural commodity because milk is produced daily, for 365 days per year. With the introduction of new technology such as the milking parlor, the global industry trend is one of increasing farm sizes. The farm sizes are the largest in the United States; however, the European Union produces the most milk compared with other global producers. Dairy production is essential for economic development and sustainable communities in rural areas. However, the required capital investment and availability of local markets and labor are continued challenges. Due to farm expansion, international producers are faced with new challenges related to assuring food safety and a safe working environment for their workforce. These challenges exist in addition to the cultural and language barriers related to an increasing dependence on immigrant labor in many regions of the world. Continued success of the global dairy industry is vital. Therefore, research should continue to address the identification of occupational risk factors associated with injuries and illnesses, as well as develop cost-effective interventions and practices that lead to the minimization or elimination of these injuries and illnesses on a global scale, among our valuable population of dairy producers and workers.

Cold Spraying of Armstrong Process Titanium Powder for Additive Manufacturing

NASA Astrophysics Data System (ADS)

MacDonald, D.; Fernández, R.; Delloro, F.; Jodoin, B.

2017-04-01

Titanium parts are ideally suited for aerospace applications due to their unique combination of high specific strength and excellent corrosion resistance. However, titanium as bulk material is expensive and challenging/costly to machine. Production of complex titanium parts through additive manufacturing looks promising, but there are still many barriers to overcome before reaching mainstream commercialization. The cold gas dynamic spraying process offers the potential for additive manufacturing of large titanium parts due to its reduced reactive environment, its simplicity to operate, and the high deposition rates it offers. A few challenges are to be addressed before the additive manufacturing potential of titanium by cold gas dynamic spraying can be reached. In particular, it is known that titanium is easy to deposit by cold gas dynamic spraying, but the deposits produced are usually porous when nitrogen is used as the carrier gas. In this work, a method to manufacture low-porosity titanium components at high deposition efficiencies is revealed. The components are produced by combining low-pressure cold spray using nitrogen as the carrier gas with low-cost titanium powder produced using the Armstrong process. The microstructure and mechanical properties of additive manufactured titanium components are investigated.

Therapeutic Potential of Thymoquinone in Glioblastoma Treatment: Targeting Major Gliomagenesis Signaling Pathways

PubMed Central

Chowdhury, Fabliha Ahmed; Hossain, Md Kamal; Mostofa, A. G. M.; Akbor, Maruf Mohammad

2018-01-01

Glioblastoma multiforme (GBM) is one of the most devastating brain tumors with median survival of one year and presents unique challenges to therapy because of its aggressive behavior. Current treatment strategy involves surgery, radiotherapy, immunotherapy, and adjuvant chemotherapy even though optimal management requires a multidisciplinary approach and knowledge of potential complications from both the disease and its treatment. Thymoquinone (TQ), the main bioactive component of Nigella sativa L., has exhibited anticancer effects in numerous preclinical studies. Due to its multitargeting nature, TQ interferes in a wide range of tumorigenic processes and counteract carcinogenesis, malignant growth, invasion, migration, and angiogenesis. TQ can specifically sensitize tumor cells towards conventional cancer treatments and minimize therapy-associated toxic effects in normal cells. Its potential to enter brain via nasal pathway due to volatile nature of TQ adds another advantage in overcoming blood-brain barrier. In this review, we summarized the potential role of TQ in different signaling pathways in GBM that have undergone treatment with standard therapeutic modalities or with TQ. Altogether, we suggest further comprehensive evaluation of TQ in preclinical and clinical level to delineate its implied utility as novel therapeutics to combat the challenges for the treatment of GBM. PMID:29651429

The Challenges of Career and Technical Education Concurrent Enrollment: An Administrative Perspective

ERIC Educational Resources Information Center

Haag, Patricia W.

2015-01-01

Career and technical education concurrent enrollment may pose unique challenges in programming and enrollment for program administrators, and this chapter describes the experiences and challenges of a CTE concurrent enrollment administrator.

Innovations in glaucoma surgery from Dr. Rajendra Prasad Centre for Ophthalmic Sciences.

PubMed

Dada, Tanuj; Midha, Neha; Shah, Pooja; Sidhu, Talvir; Angmo, Dewang; Sihota, Ramanjit

2017-02-01

Trabeculectomy surgery is the current standard of care in glaucoma for achieving a low target intraocular pressure if medical therapy is not adequate. Augmentation of trabeculectomy with antimetabolites brought a revolutionary change in the long-term success rates of trabeculectomy, but along with it came a plethora of complications. There still is a big window for therapeutic innovations on this subject. The foremost target for these innovations is to modulate the wound healing response after glaucoma drainage surgery. Achieving the desired balance between long-term success of filtering blebs versus early failure due to scarring of blebs and hypotony due to dysfunctional filtering blebs poses a unique challenge to the ophthalmologists. Alternatives to trabeculectomy such as glaucoma drainage devices and minimally invasive glaucoma surgeries cannot solve the problem of glaucoma blindness in our country, mainly due to their unpredictable results and unfavorable cost-benefit ratio. In this article, we present a summary of our innovations in glaucoma surgery to advance patient care by making it more effective, safer, and economical.

Experimental verification of Space Platform battery discharger design optimization

NASA Astrophysics Data System (ADS)

Sable, Dan M.; Deuty, Scott; Lee, Fred C.; Cho, Bo H.

The detailed design of two candidate topologies for the Space Platform battery discharger, a four module boost converter (FMBC) and a voltage-fed push-pull autotransformer (VFPPAT), is presented. Each has unique problems. The FMBC requires careful design and analysis in order to obtain good dynamic performance. This is due to the presence of a right-half-plane (RHP) zero in the control-to-output transfer function. The VFPPAT presents a challenging power stage design in order to yield high efficiency and light component weight. The authors describe the design of each of these converters and compare their efficiency, weight, and dynamic characteristics.

Platelet rich fibrin (Prf) and β-tricalcium phosphate with coronally advanced flap for the management of grade-II furcation defect.

PubMed

Sambhav, Jain; Rohit, Rai; Ranjana, Mohan; Shalabh, Mehrotra

2014-07-01

Multirooted teeth offer unique and challenging problems due to the furcation area, creates situations in which routine periodontal procedures are somewhat limited and special procedures are generally required. The present case was showing the management of grade II furcation defect by platelet rich fibrin (PRF) and β-Tricalcium phosphate with coronally advanced flap. Platelet rich fibrin and β-Tricalcium phosphate with coronally advanced flap have been shown to be a promising and successful approach for the treatment of furcation defect. Its gaining clinical attachment significantly manages both the gingival recession and furcation involvement simultaneously.

Motility Disorders in Children.

PubMed

Nurko, Samuel

2017-06-01

Gastrointestinal motility disorders in the pediatric population are common and can range from benign processes to more serious disorders. Performing and interpreting motility evaluations in children present unique challenges. There are primary motility disorders but abnormal motility may be secondary due to other disease processes. Diagnostic studies include radiographic scintigraphic and manometry studies. Although recent advances in the genetics, biology, and technical aspects are having an important impact and have allowed for a better understanding of the pathophysiology and therapy for gastrointestinal motility disorders in children, further research is needed to be done to have better understanding of the pathophysiology and for better therapies. Copyright © 2017 Elsevier Inc. All rights reserved.

Legislative intervention in Queensland to restrict access to solariums and cosmetic procedures by children and young persons.

PubMed

Cockburn, Tina; Madden, Bill

2009-02-01

Breaking new ground, Queensland has enacted laws restricting access to cosmetic surgery by those under 18 years of age. Legislation in other Australian jurisdictions is narrower in scope, focusing on niche areas such as solarium use, tattoos and body piercing. Even in those niche areas there are inconsistencies of approach and now the unique Queensland cosmetic surgery restrictions further raise the prospects of "medical tourism" and highlight the difficulties of differing legislation throughout Australia. All implementations, however, face the same challenge: to balance protection of vulnerable children, respect for a young person's autonomy and due regard to parental consent.

A Multidisciplinary Investigation of a Polycythemia Vera Cancer Cluster of Unknown Origin

PubMed Central

Seaman, Vincent; Dearwent, Steve M; Gable, Debra; Lewis, Brian; Metcalf, Susan; Orloff, Ken; Tierney, Bruce; Zhu, Jane; Logue, James; Marchetto, David; Ostroff, Stephen; Hoffman, Ronald; Xu, Mingjiang; Carey, David; Erlich, Porat; Gerhard, Glenn; Roda, Paul; Iannuzzo, Joseph; Lewis, Robert; Mellow, John; Mulvihill, Linda; Myles, Zachary; Wu, Manxia; Frank, Arthur; Gross-Davis, Carol Ann; Klotz, Judith; Lynch, Adam; Weissfeld, Joel; Weinberg, Rona; Cole, Henry

2010-01-01

Cancer cluster investigations rarely receive significant public health resource allocations due to numerous inherent challenges and the limited success of past efforts. In 2008, a cluster of polycythemia vera, a rare blood cancer with unknown etiology, was identified in northeast Pennsylvania. A multidisciplinary group of federal and state agencies, academic institutions, and local healthcare providers subsequently developed a multifaceted research portfolio designed to better understand the cause of the cluster. This research agenda represents a unique and important opportunity to demonstrate that cancer cluster investigations can produce desirable public health and scientific outcomes when necessary resources are available. PMID:20617023

Valuing morbidity from wildfire smoke exposure: a comparison of revealed and stated preference techniques

USGS Publications Warehouse

Richardson, Leslie; Loomis, John B.; Champ, Patricia A.

2013-01-01

Estimating the economic benefits of reduced health damages due to improvements in environmental quality continues to challenge economists. We review welfare measures associated with reduced wildfire smoke exposure, and a unique dataset from California’s Station Fire of 2009 allows for a comparison of cost of illness (COI) estimates with willingness to pay (WTP) measures. The WTP for one less symptom day is estimated to be $87 and $95, using the defensive behavior and contingent valuation methods, respectively. These WTP estimates are not statistically different but do differ from a $3 traditional daily COI estimate and $17 comprehensive daily COI estimate.

Experimental verification of Space Platform battery discharger design optimization

NASA Technical Reports Server (NTRS)

Sable, Dan M.; Deuty, Scott; Lee, Fred C.; Cho, Bo H.

1991-01-01

The detailed design of two candidate topologies for the Space Platform battery discharger, a four module boost converter (FMBC) and a voltage-fed push-pull autotransformer (VFPPAT), is presented. Each has unique problems. The FMBC requires careful design and analysis in order to obtain good dynamic performance. This is due to the presence of a right-half-plane (RHP) zero in the control-to-output transfer function. The VFPPAT presents a challenging power stage design in order to yield high efficiency and light component weight. The authors describe the design of each of these converters and compare their efficiency, weight, and dynamic characteristics.

Manufacturing and Security Challenges in 3D Printing

NASA Astrophysics Data System (ADS)

Zeltmann, Steven Eric; Gupta, Nikhil; Tsoutsos, Nektarios Georgios; Maniatakos, Michail; Rajendran, Jeyavijayan; Karri, Ramesh

2016-07-01

As the manufacturing time, quality, and cost associated with additive manufacturing (AM) continue to improve, more and more businesses and consumers are adopting this technology. Some of the key benefits of AM include customizing products, localizing production and reducing logistics. Due to these and numerous other benefits, AM is enabling a globally distributed manufacturing process and supply chain spanning multiple parties, and hence raises concerns about the reliability of the manufactured product. In this work, we first present a brief overview of the potential risks that exist in the cyber-physical environment of additive manufacturing. We then evaluate the risks posed by two different classes of modifications to the AM process which are representative of the challenges that are unique to AM. The risks posed are examined through mechanical testing of objects with altered printing orientation and fine internal defects. Finite element analysis and ultrasonic inspection are also used to demonstrate the potential for decreased performance and for evading detection. The results highlight several scenarios, intentional or unintentional, that can affect the product quality and pose security challenges for the additive manufacturing supply chain.

Review and Analysis of Algorithmic Approaches Developed for Prognostics on CMAPSS Dataset

NASA Technical Reports Server (NTRS)

Ramasso, Emannuel; Saxena, Abhinav

2014-01-01

Benchmarking of prognostic algorithms has been challenging due to limited availability of common datasets suitable for prognostics. In an attempt to alleviate this problem several benchmarking datasets have been collected by NASA's prognostic center of excellence and made available to the Prognostics and Health Management (PHM) community to allow evaluation and comparison of prognostics algorithms. Among those datasets are five C-MAPSS datasets that have been extremely popular due to their unique characteristics making them suitable for prognostics. The C-MAPSS datasets pose several challenges that have been tackled by different methods in the PHM literature. In particular, management of high variability due to sensor noise, effects of operating conditions, and presence of multiple simultaneous fault modes are some factors that have great impact on the generalization capabilities of prognostics algorithms. More than 70 publications have used the C-MAPSS datasets for developing data-driven prognostic algorithms. The C-MAPSS datasets are also shown to be well-suited for development of new machine learning and pattern recognition tools for several key preprocessing steps such as feature extraction and selection, failure mode assessment, operating conditions assessment, health status estimation, uncertainty management, and prognostics performance evaluation. This paper summarizes a comprehensive literature review of publications using C-MAPSS datasets and provides guidelines and references to further usage of these datasets in a manner that allows clear and consistent comparison between different approaches.

Operation Protective Edge - A Unique Challenge for a Civilian EMS Agency.

PubMed

Jaffe, Eli; Strugo, Refael; Wacht, Oren

2015-10-01

During July through August 2014, Operation Protective Edge, a military conflict between Israel and the Hamas regime in Gaza, dramatically affected both populations. Magen David Adom (MDA), the Israeli national Emergency Medical Service (EMS) and a member of the Red Cross, faced a unique challenge during the conflict: to continue providing crucial service to the entire civilian population of Israel, which was under constant missile threat. This challenge included not only providing immediate care for routine EMS calls under missile threat, but also preparing and delivering immediate care to civilians injured in attacks on major cities, as well as small communities, in Israel. This task is a challenge for a civilian EMS agency that normally operates in a non-military environment, yet, in an instant, must enhance its capability to respond to a considerable threat to its population. During Operation Protective Edge, MDA provided care for 842 wounded civilians and utilized a significant amount of its resources. Providing EMS services for a civilian population in a mixed civilian/military scenario is a challenging task on a national level for an EMS system, especially when the threat lasts for weeks. This report describes MDA's preparedness and operations during Operation Protective Edge, and the unique EMS challenges and dilemmas the agency faced.

Sports Dermatology: Part 1 of 2 Traumatic or Mechanical Injuries, Inflammatory Conditions, and Exacerbations of Pre-existing Conditions

PubMed Central

Sivek, Rachel; Marciniak, Brian

2015-01-01

Competitive athletes endure extreme bodily stress when participating in sports-related activities. An athlete’s skin is particularly susceptible to a wide array of repetitive physical and environmental stressors that challenge the skin’s protective function. Many unique dermatoses are well-known to the serious athlete due to countless hours of intense physical training, but are frequently unrecognized by many healthcare professionals. Sports dermatology is a distinctive, budding field of dermatology that focuses on dermatoses frequently encountered in athletes. Athletic skin problems are notoriously infectious in nature due to the inherent environment of close-contact physical activity. Nonetheless, other skin conditions can manifest or worsen with recurring mechanical or traumatic injury or exposure to environmental hazards. Additionally, sports-related activities may exacerbate other pre-existing dermatological conditions that may possibly be unknown to the athlete or clinician. The objective of this two-part review is to arm the astute physician with the fundamental knowledge of the range of dermatological conditions distinct to the competitive athlete. Knowledge of these cutaneous conditions in the context of specific sporting events will permit the clinician to manage these unique patients most effectively. Part one will focus on traumatic or mechanical injuries, inflammatory conditions, and exacerbations of pre-existing conditions frequently seen in athletes. PMID:26060516

Use and application of gelatin as potential biodegradable packaging materials for food products.

PubMed

Nur Hanani, Z A; Roos, Y H; Kerry, J P

2014-11-01

The manufacture and potential application of biodegradable films for food application has gained increased interest as alternatives to conventional food packaging polymers due to the sustainable nature associated with their availability, broad and abundant source range, compostability, environmentally-friendly image, compatibility with foodstuffs and food application, etc. Gelatin is one such material and is a unique and popularly used hydrocolloid by the food industry today due to its inherent characteristics, thereby potentially offering a wide range of further and unique industrial applications. Gelatin from different sources have different physical and chemical properties as they contain different amino acid contents which are responsible for the varying characteristics observed upon utilization in food systems and when being utilized more specifically, in the manufacture of films. Packaging films can be successfully produced from all gelatin sources and the behaviour and characteristics of gelatin-based films can be altered through the incorporation of other food ingredients to produce composite films possessing enhanced physical and mechanical properties. This review will present the current situation with respect to gelatin usage as a packaging source material and the challenges that remain in order to move the manufacture of gelatin-based films nearer to commercial reality. Copyright © 2014 Elsevier B.V. All rights reserved.

Rapid, all dry microfabrication of three-dimensional Co3O4/Pt nanonetworks for high-performance microsupercapacitors.

PubMed

Ma, Xinyu; Feng, Shuxuan; He, Liang; Yan, Mengyu; Tian, Xiaocong; Li, Yanxi; Tang, Chunjuan; Hong, Xufeng; Mai, Liqiang

2017-08-17

On-chip electrochemical energy storage devices have attracted growing attention due to the decreasing size of electronic devices. Various approaches have been applied for constructing the microsupercapacitors. However, the microfabrication of high-performance microsupercapacitors by conventional and fully compatible semiconductor microfabrication technologies is still a critical challenge. Herein, unique three-dimensional (3D) Co 3 O 4 nanonetwork microelectrodes formed by the interconnection of Co 3 O 4 nanosheets are constructed by controllable physical vapor deposition combined with rapid thermal annealing. This construction process is an all dry and rapid (≤5 minutes) procedure. Afterward, by sputtering highly electrically conductive Pt nanoparticles on the microelectrodes, the 3D Co 3 O 4 /Pt nanonetworks based microsupercapacitor is fabricated, showing a high volume capacitance (35.7 F cm -3 ) at a scan rate of 20 mV s -1 due to the unique interconnected structures, high electrical conductivity and high surface area of the microelectrodes. This microfabrication process is also used to construct high-performance flexible microsupercapacitors, and it can be applied in the construction of wearable devices. The proposed strategy is completely compatible with the current semiconductor microfabrication and shows great potential in the applications of the large-scale integration of micro/nano and wearable devices.

Flexible transparent and free-standing silicon nanowires paper.

PubMed

Pang, Chunlei; Cui, Hao; Yang, Guowei; Wang, Chengxin

2013-10-09

If the flexible transparent and free-standing paper-like materials that would be expected to meet emerging technological demands, such as components of transparent electrical batteries, flexible solar cells, bendable electronics, paper displays, wearable computers, and so on, could be achieved in silicon, it is no doubt that the traditional semiconductor materials would be rejuvenated. Bulk silicon cannot provide a solution because it usually exhibits brittleness at below their melting point temperature due to high Peierls stress. Fortunately, when the silicon's size goes down to nanoscale, it possesses the ultralarge straining ability, which results in the possibility to design flexible transparent and self-standing silicon nanowires paper (FTS-SiNWsP). However, realization of the FTS-SiNWsP is still a challenging task due largely to the subtlety in the preparation of a unique interlocking alignment with free-catalyst controllable growth. Herein, we present a simple synthetic strategy by gas flow directed assembly of a unique interlocking alignment of the Si nanowires (SiNWs) to produce, for the first time, the FTS-SiNWsP, which consisted of interconnected SiNWs with the diameter of ~10 nm via simply free-catalyst thermal evaporation in a vertical high-frequency induction furnace. This approach opens up the possibility for creating various flexible transparent functional devices based on the FTS-SiNWsP.

Financial stability in biobanking: unique challenges for disease-focused foundations and patient advocacy organizations.

PubMed

Bromley, Russell L

2014-10-01

In the last decade, many disease-focused foundations and patient advocacy organizations that support biomedical research have created patient registries and biobanks. This article reviews the motivations behind the creation of those biobanks and how they are different from biobanks sponsored by government or industry. It also discusses some of the different funding models being employed by these organizations. Finally, it highlights some of the unique challenges faced by disease-focused foundations and advocacy organizations that sponsor biobanks, and how they are overcoming those challenges to achieve both financial and operational sustainability.

Advanced nanocarriers based on heparin and its derivatives for cancer management.

PubMed

Yang, Xiaoye; Du, Hongliang; Liu, Jiyong; Zhai, Guangxi

2015-02-09

To obtain a satisfying anticancer effect, rationally designed nanocarriers are intensively studied. In this field, heparin and its derivatives have been widely attempted recently as potential component of nanocarriers due to their unique biological and physiochemical features, especially the anticancer activity. This review focuses on state-of-the-art nanocarriers with heparin/heparin derivatives as backbone or coating material. At the beginning, the unique advantages of heparin used in cancer nanotechnology are discussed. After that, different strategies of heparin chemical modification are reviewed, laying the foundation of developing various nanocarriers. Then a systematic summary of diverse nanoparticles with heparin as component is exhibited, involving heparin-drug conjugate, polymeric nanoparticles, nanogels, polyelectrolyte complex nanoparticles, and heparin-coated organic and inorganic nanoparticles. The application of these nanoparticles in various novel cancer therapy (containing targeted therapy, magnetic therapy, photodynamic therapy, and gene therapy) will be highlighted. Finally, future challenges and opportunities of heparin-based biomaterials in cancer nanotechnology are discussed.

Towards efficient bioethanol production from agricultural and forestry residues: Exploration of unique natural microorganisms in combination with advanced strain engineering.

PubMed

Zhao, Xinqing; Xiong, Liang; Zhang, Mingming; Bai, Fengwu

2016-09-01

Production of fuel ethanol from lignocellulosic feedstocks such as agricultural and forestry residues is receiving increasing attention due to the unsustainable supply of fossil fuels. Three key challenges include high cellulase production cost, toxicity of the cellulosic hydrolysate to microbial strains, and poor ability of fermenting microorganisms to utilize certain fermentable sugars in the hydrolysate. In this article, studies on searching of natural microbial strains for production of unique cellulase for biorefinery of agricultural and forestry wastes, as well as development of strains for improved cellulase production were reviewed. In addition, progress in the construction of yeast strains with improved stress tolerance and the capability to fully utilize xylose and glucose in the cellulosic hydrolysate was also summarized. With the superior microbial strains for high titer cellulase production and efficient utilization of all fermentable sugars in the hydrolysate, economic biofuels production from agricultural residues and forestry wastes can be realized. Copyright © 2016 Elsevier Ltd. All rights reserved.

Degradation of Silicone Encapsulants in CPV Optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Can; Miller, David C.; Tappan, Ian A.

High efficiency multijunction solar cells in terrestrial concentrator photovoltaic (CPV) modules are becoming an increasingly cost effective and viable option in utility scale power generation. As with other utility scale photovoltaics, CPV modules need to guarantee operational lifetimes of at least 25 years. The reliability of optical elements in CPV modules poses a unique materials challenge due to the increased UV irradiance and enhanced temperature cycling associated with concentrated solar flux. The polymeric and thin film materials used in the optical elements are especially susceptible to UV damage, diurnal temperature cycling and active chemical species from the environment. We usedmore » fracture mechanics approaches to study the degradation modes including: the adhesion between the encapsulant and the cell or secondary optical element; and the cohesion of the encapsulant itself. Understanding the underlying mechanisms of materials degradation under elevated stress conditions is critical for commercialization of CPV technology and can offer unique insights into degradation modes in similar encapsulants used in other photovoltaic modules.« less

Degradation of Silicone Encapsulants in CPV Optics: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, David C.; Tappan, Ian A.; Cai, Can

High efficiency multijunction solar cells in terrestrial concentrator photovoltaic (CPV) modules are becoming an increasingly cost effective and viable option in utility scale power generation. As with other utility scale photovoltaics, CPV modules need to guarantee operational lifetimes of at least 25 years. The reliability of optical elements in CPV modules poses a unique materials challenge due to the increased UV irradiance and enhanced temperature cycling associated with concentrated solar flux. The polymeric and thin film materials used in the optical elements are especially susceptible to UV damage, diurnal temperature cycling and active chemical species from the environment. We usedmore » fracture mechanics approaches to study the degradation modes including: the adhesion between the encapsulant and the cell or secondary optical element; and the cohesion of the encapsulant itself. Understanding the underlying mechanisms of materials degradation under elevated stress conditions is critical for commercialization of CPV technology and can offer unique insights into degradation modes in similar encapsulants used in other photovoltaic modules.« less

Critical Review of Removal of Nano Materials in Waste Streams

NASA Astrophysics Data System (ADS)

Leung, Solomon W.; Williams, Bradley; De Jesus, Karl; Lai, James C. K.

2017-05-01

Industrial applications of nanomaterials (NMs) are rising drastically in recent years and the commercial value of these materials can reach over 100 billion in 5 years. Major effort in nano research has been devoted to the utilities of the materials, only minimum effort has been directed to the disposal, reuse, and recycle of these new forms of materials. Due to their unique sizes and sharps, nanomaterials possess unique characteristics and toxicity that are not expected from their counterparts in meso/micro forms. At the present time, there are no regulations governing the handling and disposals of NMs, but recent research demonstrated that NMs are more hazardous than we realize. A main reason why less caution is being exercised by the general public regarding NMs is that the measurement and quantitation of NMs are difficult, which lead to difficulties in monitoring, thus regulation. This article critically reviewed over the issues stemming from the development of NMs, especially the challenges of measurement and disposal of these materials in landfills.

Intracellular production of hydrogels and synthetic RNA granules by multivalent enhancers

PubMed Central

Nakamura, Hideki; Lee, Albert A.; Afshar, Ali Sobhi; Watanabe, Shigeki; Rho, Elmer; Razavi, Shiva; Suarez, Allison; Lin, Yu-Chun; Tanigawa, Makoto; Huang, Brian; DeRose, Robert; Bobb, Diana; Hong, William; Gabelli, Sandra B.; Goutsias, John; Inoue, Takanari

2018-01-01

Non-membrane bound, hydrogel-like entities, such as RNA granules, nucleate essential cellular functions through their unique physico-chemical properties. However, these intracellular hydrogels have not been as extensively studied as their extracellular counterparts, primarily due to technical challenges in probing these materials in situ. Here, by taking advantage of a chemically inducible dimerization paradigm, we developed iPOLYMER, a strategy for rapid induction of protein-based hydrogels inside living cells. A series of biochemical and biophysical characterizations, in conjunction with computational modeling, revealed that the polymer network formed in the cytosol resembles a physiological hydrogel-like entity that behaves as a size-dependent molecular sieve. We studied several properties of the gel and functionalized it with RNA binding motifs that sequester polyadenine-containing nucleotides to synthetically mimic RNA granules. Therefore, we here demonstrate that iPOLYMER presents a unique and powerful approach to synthetically reconstitute hydrogel-like structures including RNA granules in intact cells. PMID:29115293

Vagal Reactivity and Affective Adjustment in Infants during Interaction Challenges.

ERIC Educational Resources Information Center

Bazhenova, Olga V.; Plonskaia, Oxana; Porges, Stephen W.

2001-01-01

Evaluated respiratory sinus arrhythmia (RSA) and heart period in 5-month-olds during interaction challenges. Found that during object-mediated challenge, RSA increases were uniquely related to positive engagement. During person-mediated challenge, subjects showed more complex integration of autonomic and behavioral responses such that only infants…

Technology Challenges in Small UAV Development

NASA Technical Reports Server (NTRS)

Logan, Michael J.; Vranas, Thomas L.; Motter, Mark; Shams, Qamar; Pollock, Dion S.

2005-01-01

Development of highly capable small UAVs present unique challenges for technology protagonists. Size constraints, the desire for ultra low cost and/or disposable platforms, lack of capable design and analysis tools, and unique mission requirements all add to the level of difficulty in creating state-of-the-art small UAVs. This paper presents the results of several small UAV developments, the difficulties encountered, and proposes a list of technology shortfalls that need to be addressed.

Laboratory Information Systems in Molecular Diagnostics: Why Molecular Diagnostics Data are Different.

PubMed

Lee, Roy E; Henricks, Walter H; Sirintrapun, Sahussapont J

2016-03-01

Molecular diagnostic testing presents new challenges to information management that are yet to be sufficiently addressed by currently available information systems for the molecular laboratory. These challenges relate to unique aspects of molecular genetic testing: molecular test ordering, informed consent issues, diverse specimen types that encompass the full breadth of specimens handled by traditional anatomic and clinical pathology information systems, data structures and data elements specific to molecular testing, varied testing workflows and protocols, diverse instrument outputs, unique needs and requirements of molecular test reporting, and nuances related to the dissemination of molecular pathology test reports. By satisfactorily addressing these needs in molecular test data management, a laboratory information system designed for the unique needs of molecular diagnostics presents a compelling reason to migrate away from the current paper and spreadsheet information management that many molecular laboratories currently use. This paper reviews the issues and challenges of information management in the molecular diagnostics laboratory.

The Challenges of Prevention, Diagnosis and Treatment of Ischemic Heart Disease in Women

PubMed Central

Brewer, LaPrincess C.; Svatikova, Anna

2017-01-01

Increasing evidence suggests that there are significant differences in the presentation, diagnosis and treatment of ischemic heart disease in women compared to men. Women often present with atypical symptoms, and this, in association with a consistent underestimation of their risk for ischemic heart disease, leads to underdiagnosis and undertreatment in women. Cardiovascular risk factors unique to women have only recently been recognized, and moreover, traditional risk factors have recently been shown to have greater impacts on women. Consequently, women suffer more disability and poorer clinical outcomes, with higher cardiovascular morbidity and mortality. These discrepancies may in part be secondary to the higher prevalence of nonobstructive coronary artery disease in women with persistent chest pain symptoms as compared to men when evaluated invasively. Focused diagnostic and therapeutic strategies unique to women are thus needed, but unfortunately, such sex-specific guidelines do not yet exist, largely due to lack of awareness, both on the part of providers and patients, as well as a paucity of evidence-based research specific to women. Although underutilized in women, diagnostic modalities, including functional and anatomic cardiac tests as well as physiologic assessments of endothelial and microvascular function, are useful for establishing the diagnosis and prognosis of suspected ischemic heart disease in women. This review discusses the current challenges of prevention, diagnosis and treatment of ischemic heart disease in women. PMID:26210899

Diameter-dependent wetting of tungsten disulfide nanotubes

PubMed Central

Goldbart, Ohad; Cohen, Sidney R.; Kaplan-Ashiri, Ifat; Glazyrina, Polina; Wagner, H. Daniel; Enyashin, Andrey; Tenne, Reshef

2016-01-01

The simple process of a liquid wetting a solid surface is controlled by a plethora of factors—surface texture, liquid droplet size and shape, energetics of both liquid and solid surfaces, as well as their interface. Studying these events at the nanoscale provides insights into the molecular basis of wetting. Nanotube wetting studies are particularly challenging due to their unique shape and small size. Nonetheless, the success of nanotubes, particularly inorganic ones, as fillers in composite materials makes it essential to understand how common liquids wet them. Here, we present a comprehensive wetting study of individual tungsten disulfide nanotubes by water. We reveal the nature of interaction at the inert outer wall and show that remarkably high wetting forces are attained on small, open-ended nanotubes due to capillary aspiration into the hollow core. This study provides a theoretical and experimental paradigm for this intricate problem. PMID:27856759

Surface engineering of graphene-based nanomaterials for biomedical applications.

PubMed

Shi, Sixiang; Chen, Feng; Ehlerding, Emily B; Cai, Weibo

2014-09-17

Graphene-based nanomaterials have attracted tremendous interest over the past decade due to their unique electronic, optical, mechanical, and chemical properties. However, the biomedical applications of these intriguing nanomaterials are still limited due to their suboptimal solubility/biocompatibility, potential toxicity, and difficulties in achieving active tumor targeting, just to name a few. In this Topical Review, we will discuss in detail the important role of surface engineering (i.e., bioconjugation) in improving the in vitro/in vivo stability and enriching the functionality of graphene-based nanomaterials, which can enable single/multimodality imaging (e.g., optical imaging, positron emission tomography, magnetic resonance imaging) and therapy (e.g., photothermal therapy, photodynamic therapy, and drug/gene delivery) of cancer. Current challenges and future research directions are also discussed and we believe that graphene-based nanomaterials are attractive nanoplatforms for a broad array of future biomedical applications.

Experiences Gained Creating a Biophysics Major at a Predominately Undergraduate Institution

NASA Astrophysics Data System (ADS)

Link, Justin; Herbert, Steven

2014-03-01

Xavier University, a liberal arts predominately undergraduate institution (PUI) located in Cincinnati, OH, implemented a Biophysics major in the Department of Physics in spring 2012. The program is built upon foundational physics courses and is unique due to the possible selection of upper-division courses that students elect to take towards their undergraduate degree. A capstone course is offered to bring all prior knowledge in the fundamental sciences together to approach complex problems in biology. Due to the flexibility of the program, it serves students well who are interested in pursuing advanced degrees in Biophysics or Biomedical Engineering. It also offers students interested in the health professions an alternate path towards medical school which can be advantageous in the application process. This session will express some of the advantages and challenges to creating such a program at a liberal arts PUI and discuss the capstone course within the major.

Mussel-inspired synthesis of polydopamine-functionalized graphene oxide hydrogel as broad-spectrum antimicrobial material

NASA Astrophysics Data System (ADS)

Wang, Xinpeng; Liu, Zhiming; Zhong, Huiqing; Guo, Zhouyi; Yuan, Xiaochan

2014-09-01

Recently, three-dimensional GO-based hydrogels have attracted great attention due to the unique advantages. It is generally know that bacteria are everywhere and many of them could cause the diseases and threaten human health. However, developing new antibacterial materials with high-efficiency, low cost, broad-spectrum, and easy recycling is still a great challenge. Herein, inspired by mussel, we synthesized benzalkonium bromide/polydopamine/reduced graphene oxide hydrogel (BKB/PDA/rGOG). The as-prepared three-dimensional hydrogels were characterized by scanning eletron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy. The resultant hydrogels exhibited strong antibacterial effects to both Gram-negative and Gram-positive bacteria due to the synergistic effect of graphene oxide and benzalkonium bromide. In addition, the resultant hydrogels could be removed easily from the resolution, which was undoubtedly good news for industry application.

Risk Considerations of Bird Strikes to Space Launch Vehicles

NASA Technical Reports Server (NTRS)

Hales, Christy; Ring, Robert

2016-01-01

Within seconds after liftoff of the Space Shuttle during mission STS-114, a turkey vulture impacted the vehicle's external tank. The contact caused no apparent damage to the Shuttle, but the incident led NASA to consider the potential consequences of bird strikes during a Shuttle launch. The environment at Kennedy Space Center provides unique bird strike challenges due to the Merritt Island National Wildlife Refuge and the Atlantic Flyway bird migration routes. NASA is currently refining risk assessment estimates for the probability of bird strike to space launch vehicles. This paper presents an approach for analyzing the risks of bird strikes to space launch vehicles and presents an example. The migration routes, types of birds present, altitudes of those birds, exposed area of the launch vehicle, and its capability to withstand impacts affect the risk due to bird strike. A summary of significant risk contributors is discussed.

Graphene and graphene nanocomposites for the removal of aromatic organic compounds from the water: systematic review

NASA Astrophysics Data System (ADS)

Monsores Paixão, Monique; Tadeu Gomes Vianna, Marco; Marques, Marcia

2018-01-01

Aromatic organic pollutants are highly toxic to the human and environmental health and are considered as priority pollutants by regulatory agencies. Managing contaminated sites with organic pollutants is one of the major environmental challenges today. Of all technologies that have been proposed to remove contaminants, adsorption is recognized worldwide as an attractive option due to its versatility, wide applicability and economic viability. Recent studies report the use of graphene (GN), a recently carbon nanomaterial, and its derivatives in sorption processes for the removal of aromatic organic compounds. The present review has shown that GN structures are a promising alternative to traditional adsorbent materials, with excellent results in the removal of organic compounds from water, due to their unique structural characteristics and great adsorption capacity for organic compounds. Although, there is still a long way to go until that practical applications can be implemented.

Postoperative Refractive Errors Following Pediatric Cataract Extraction with Intraocular Lens Implantation.

PubMed

Indaram, Maanasa; VanderVeen, Deborah K

2018-01-01

Advances in surgical techniques allow implantation of intraocular lenses (IOL) with cataract extraction, even in young children. However, there are several challenges unique to the pediatric population that result in greater degrees of postoperative refractive error compared to adults. Literature review of the techniques and outcomes of pediatric cataract surgery with IOL implantation. Pediatric cataract surgery is associated with several sources of postoperative refractive error. These include planned refractive error based on age or fellow eye status, loss of accommodation, and unexpected refractive errors due to inaccuracies in biometry technique, use of IOL power formulas based on adult normative values, and late refractive changes due to unpredictable eye growth. Several factors can preclude the achievement of optimal refractive status following pediatric cataract extraction with IOL implantation. There is a need for new technology to reduce postoperative refractive surprises and address refractive adjustment in a growing eye.

Ir-Catalyzed, Silyl-Directed, peri-Borylation of C-H Bonds in Fused Polycyclic Arenes and Heteroarenes.

PubMed

Su, Bo; Hartwig, John F

2018-05-20

peri-Disubstituted naphthalenes exhibit interesting physical properties and unique chemical reactivity, due to the parallel arrangement of the bonds to the two peri-disposed substituents. Regioselective installation of a functional group at the position peri to 1-substituted naphthalenes is challenging due to the steric interaction between the existing substituent and the position at which the second one would be installed. We report an iridium-catalyzed borylation of the C-H bond peri to a silyl group in naphthalenes and analogous polyaromatic hydrocarbons. The reaction occurs under mild conditions with wide functional group tolerance. The silyl group and the boryl group in the resulting products are precursors to a range of functional groups bound to the naphthalene ring through C-C, C-O, C-N, C-Br and C-Cl bonds. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Bayesian Measurment Error Model for Misaligned Radiographic Data

DOE PAGES

Lennox, Kristin P.; Glascoe, Lee G.

2013-09-06

An understanding of the inherent variability in micro-computed tomography (micro-CT) data is essential to tasks such as statistical process control and the validation of radiographic simulation tools. The data present unique challenges to variability analysis due to the relatively low resolution of radiographs, and also due to minor variations from run to run which can result in misalignment or magnification changes between repeated measurements of a sample. Positioning changes artificially inflate the variability of the data in ways that mask true physical phenomena. We present a novel Bayesian nonparametric regression model that incorporates both additive and multiplicative measurement error inmore » addition to heteroscedasticity to address this problem. We also use this model to assess the effects of sample thickness and sample position on measurement variability for an aluminum specimen. Supplementary materials for this article are available online.« less

Communication: Enhanced chemical reactivity of graphene on a Ni(111) substrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ambrosetti, Alberto; Silvestrelli, Pier Luigi

2016-03-21

Due to the unique combination of structural, mechanical, and transport properties, graphene has emerged as an exceptional candidate for catalysis applications. The low chemical reactivity caused by sp{sup 2} hybridization and strongly delocalized π electrons, however, represents a main challenge for straightforward use of graphene in its pristine, free-standing form. Following recent experimental indications, we show that due to charge hybridization, a Ni(111) substrate can enhance the chemical reactivity of graphene, as exemplified by the interaction with the CO molecule. While CO only physisorbs on free-standing graphene, chemisorption of CO involving formation of ethylene dione complexes is predicted in Ni(111)-graphene.more » Higher chemical reactivity is also suggested in the case of oxidized graphene, opening the way to a simple and efficient control of graphene chemical properties, devoid of complex defect patterning or active metallic structures deposition.« less

Surface Engineering of Graphene-Based Nanomaterials for Biomedical Applications

PubMed Central

2015-01-01

Graphene-based nanomaterials have attracted tremendous interest over the past decade due to their unique electronic, optical, mechanical, and chemical properties. However, the biomedical applications of these intriguing nanomaterials are still limited due to their suboptimal solubility/biocompatibility, potential toxicity, and difficulties in achieving active tumor targeting, just to name a few. In this Topical Review, we will discuss in detail the important role of surface engineering (i.e., bioconjugation) in improving the in vitro/in vivo stability and enriching the functionality of graphene-based nanomaterials, which can enable single/multimodality imaging (e.g., optical imaging, positron emission tomography, magnetic resonance imaging) and therapy (e.g., photothermal therapy, photodynamic therapy, and drug/gene delivery) of cancer. Current challenges and future research directions are also discussed and we believe that graphene-based nanomaterials are attractive nanoplatforms for a broad array of future biomedical applications. PMID:25117569

Alignment of a multilayer-coated imaging system using extreme ultraviolet Foucault and Ronchi interferometric testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ray-Chaudhuri, A.K.; Ng, W.; Cerrina, F.

1995-11-01

Multilayer-coated imaging systems for extreme ultraviolet (EUV) lithography at 13 nm represent a significant challenge for alignment and characterization. The standard practice of utilizing visible light interferometry fundamentally provides an incomplete picture since this technique fails to account for phase effects induced by the multilayer coating. Thus the development of optical techniques at the functional EUV wavelength is required. We present the development of two EUV optical tests based on Foucault and Ronchi techniques. These relatively simple techniques are extremely sensitive due to the factor of 50 reduction in wavelength. Both techniques were utilized to align a Mo--Si multilayer-coated Schwarzschildmore » camera. By varying the illumination wavelength, phase shift effects due to the interplay of multilayer coating and incident angle were uniquely detected. {copyright} {ital 1995} {ital American} {ital Vacuum} {ital Society}« less

Challenges in the assessment of total fluid intake in children and adolescents: a discussion paper.

PubMed

Warren, Janet; Guelinckx, Isabelle; Livingstone, Barbara; Potischman, Nancy; Nelson, Michael; Foster, Emma; Holmes, Bridget

2018-06-01

In recent years, evidence has emerged about the importance of healthy fluid intake in children for physical and mental performance and health, and in the prevention of obesity. Accurate data on water intake are needed to inform researchers and policymakers and for setting dietary reference values. However, to date, there are few published data on fluid or water intakes in children. This is due partly to the fact that drinking water is not always reported in dietary surveys. The aim of this paper is to review the current status of the literature and highlight the challenges of assessing total fluid intake in children and adolescents. From the dietary assessment literature it is apparent that children present unique challenges to assessing intake due to ongoing cognitive capacity development, limited literacy skills, difficulties in estimating portion sizes and multiple caregivers during any 1 day making it difficult to track intakes. As such, many issues should be considered when assessing total fluid intakes in children or adolescents. Various methods to assess fluid intakes exist, each with its own strengths and weaknesses; the ultimate choice of method depends on the research question and resources available. Based on the literature review, it is apparent that if the research focus is to assess only fluid intake, a fluid-specific method, such as a diary or record, appears to be a feasible approach to provide an accurate estimate of intakes.

Promises and challenges in solid-state lighting

NASA Astrophysics Data System (ADS)

Schubert, Fred

2010-03-01

Lighting technologies based on semiconductor light-emitting diodes (LEDs) offer unprecedented promises that include three major benefits: (i) Gigantic energy savings enabled by efficient conversion of electrical energy to optical energy; (ii) Substantial positive contributions to sustainability through reduced emissions of global-warming gases, acid-rain gases, and toxic substances such as mercury; and (iii) The creation of new paradigms in lighting driven by the unique controllability of solid-state lighting sources. Due to the powerful nature of these benefits, the transition from conventional lighting sources to solid-state lighting is virtually assured. This presentation will illustrate the new world of lighting and illustrate the pervasive changes to be expected in lighting, displays, communications, and biotechnology. The presentation will also address the formidable challenges that must be addressed to continue the further advancement of solid-state lighting technology. These challenges offer opportunities for research and innovation. Specific challenges include light management, carrier transport, and optical design. We will present some innovative approaches in order to solve known technical challenges faced by solid-state lighting. These approaches include the demonstration and use of new optical thin-film materials with a continuously tunable refractive index. These approaches also include the use of polarization-matched structures that reduce the polarization fields in GaInN LEDs and the hotly debated efficiency droop, that is, the decreasing LED efficiency at high currents.

Family-centred care in the paediatric intensive care unit: an integrative review of the literature.

PubMed

Butler, Ashleigh; Copnell, Beverley; Willetts, Georgina

2014-08-01

To review extant research on family-centred care in a paediatric intensive care environment and identify gaps in the literature. Family-centred care is currently a core concept in paediatric nursing, focusing on the premise that families are central to a child's well-being, and as such, should be included as equal members of the child's healthcare team. Due to the nature of critical care, family-centred care may be challenging to implement and maintain. An integrative literature review. The review was conducted using the Cumulative Index to Nursing and Allied Health Literature, PubMed, OVID MEDLINE and Google Scholar databases, from 1990 to present. The search focused on the following terms: 'p(a)ediatric critical care', 'paediatric intensive care unit', 'family cent(e)red care', 'parental needs', 'family presence' and 'family/nurse roles'. Additionally, the search was limited to studies conducted in a developed country and published in English. Eighteen studies were included in the review. The results demonstrated that implementing family-centred care into a paediatric intensive care environment posed several challenges. The discrepancy between nurses' and parents' perception of their roles, the reluctance of medical staff to share potentially negative or rapidly changing information, restrictive family presence and poor understanding of family needs emerged as the key difficulties. No studies evaluated strategies to improve family-centred care practice. Family-centred care presents many challenges in a paediatric intensive care environment; however, nurses are uniquely positioned to foster relationships with families, encourage accurate and honest information sharing and advocate for families to be present when they choose. This review outlines the extant research to enhance awareness of the unique state of family-centred care in paediatric intensive care and makes recommendations for future research. © 2013 John Wiley & Sons Ltd.

Improving support and education of low-income baby boomers diagnosed with chronic hepatitis C virus infection through universal screening.

PubMed

Turner, Barbara J; Craig, Kathryn; Makanji, Vidhi S; Flores, Bertha E; Hernandez, Ludivina

2017-12-01

To identify support needs of low-income baby boomers recently diagnosed with chronic hepatitis C virus infection. The U.S. Preventive Services Task Force has endorsed one-time screening of all baby boomers (born 1945-1965) for hepatitis C because 75% of the estimated 2-3 million persons with chronic infection are in this age range. We hypothesised that persons diagnosed by routine screening would have significant psycho-emotional, cognitive and healthcare challenges that need to be met by collaborative care and services from nurses and other healthcare personnel. Qualitative descriptive study of data from three focus groups with predominantly minority participants (N = 16). Data were analysed using qualitative content analysis, and transcribed data were categorised by three domains in a previously developed model and a new domain identified in this study. Frequencies of unique participants' comments about each theme were calculated. Elucidated domains were as follows: (i) psycho-emotional effects due to social stigma, shame, fear and dealing with risky behaviours; (ii) social effects due to concerns about infecting others; and (iii) cognitive deficits because of poor understanding about hepatitis C virus infection and its care. A new domain related to health care emerged reflecting the following themes: poor access to care, barriers to costly treatment, and navigating complex care for comorbidities. Despite these challenges, participants strongly endorsed universal baby boomer hepatitis C virus screening. This study describes psycho-emotional and social challenges of people dealing with a hepatitis C diagnosis which are compounded by poor knowledge and barriers to supportive care. Nursing and other allied health personnel require structured support programmes to assist older persons diagnosed with hepatitis C with addressing these common challenges with the ultimate goal of achieving a cure. © 2017 John Wiley & Sons Ltd.

Model-based nonlinear control of hydraulic servo systems: Challenges, developments and perspectives

NASA Astrophysics Data System (ADS)

Yao, Jianyong

2018-06-01

Hydraulic servo system plays a significant role in industries, and usually acts as a core point in control and power transmission. Although linear theory-based control methods have been well established, advanced controller design methods for hydraulic servo system to achieve high performance is still an unending pursuit along with the development of modern industry. Essential nonlinearity is a unique feature and makes model-based nonlinear control more attractive, due to benefit from prior knowledge of the servo valve controlled hydraulic system. In this paper, a discussion for challenges in model-based nonlinear control, latest developments and brief perspectives of hydraulic servo systems are presented: Modelling uncertainty in hydraulic system is a major challenge, which includes parametric uncertainty and time-varying disturbance; some specific requirements also arise ad hoc difficulties such as nonlinear friction during low velocity tracking, severe disturbance, periodic disturbance, etc.; to handle various challenges, nonlinear solutions including parameter adaptation, nonlinear robust control, state and disturbance observation, backstepping design and so on, are proposed and integrated, theoretical analysis and lots of applications reveal their powerful capability to solve pertinent problems; and at the end, some perspectives and associated research topics (measurement noise, constraints, inner valve dynamics, input nonlinearity, etc.) in nonlinear hydraulic servo control are briefly explored and discussed.

Connecting the records: exploiting tephra deposits to help understand abrupt climate change

NASA Astrophysics Data System (ADS)

Davies, S. M.; Abbott, P. M.; Bourne, A. J.; Chapman, M.; Pearce, N. J. G.; Griggs, A. J.; Cook, E.

2016-12-01

The causal mechanism of abrupt climate change during the last glacial period remains a key challenge. Although these events are well-documented in a wide range of proxy records, the triggers and drivers remain poorly understood, largely due to the dating uncertainties that prevent the integration of different archives. Unravelling the lead/lag responses (hence cause and effect) between the Earth's climate components is limited by the challenges of synchronising palaeoclimate records on a common timescale. Here we present the potential and the challenges of optimising the use of cryptotephra deposits to precisely correlate the Greenland ice-cores with North Atlantic marine records. A series of new cryptotephra deposits have been identified in Greenland, increasing the scope of identifying coeval isochrons in the marine environment. This new framework, however, brings new challenges in the search for unique and robust geochemical fingerprints for unequivocal tephra correlations. As such, some tephra deposits are proposed to be more valuable than others and underpin key snapshots in time during the last glacial period. The North Atlantic Ash Zone II, for instance, represents the most widespread isochron and constrains the cooling of GI-15. Some tephra deposits in the ice-core record originate from ultra-distal sources beyond the North Atlantic region and we also explore the potential for establishing North Pacific linkages.

Life Support Requirements and Challenges for NASA's Constellation Program

NASA Technical Reports Server (NTRS)

Carasquillo, Robyn

2007-01-01

NASA's Constellation Program, which includes the mission objectives of establishing a permanently-manned lunar Outpost, and the exploration of Mars, poses new and unique challenges for human life support systems that will require solutions beyond the Shuttle and International Space Station state of the art systems. In particular, the requirement to support crews for 210 days duration at the lunar outpost with limited resource resupply capability wilt require closed-loop regenerative life support systems with minimal expendables. Planetary environmental conditions such as lunar dust and extreme temperatures, as well as the capability to support frequent and extended-duration EVA's will be particularly challenging. This presentation will summarize the key program and mission life support requirements for the Constellation Program and the unique challenges they present for technology and architecture development.

New Strategies and Challenges in Lung Proteomics and Metabolomics. An Official American Thoracic Society Workshop Report.

PubMed

Bowler, Russell P; Wendt, Chris H; Fessler, Michael B; Foster, Matthew W; Kelly, Rachel S; Lasky-Su, Jessica; Rogers, Angela J; Stringer, Kathleen A; Winston, Brent W

2017-12-01

This document presents the proceedings from the workshop entitled, "New Strategies and Challenges in Lung Proteomics and Metabolomics" held February 4th-5th, 2016, in Denver, Colorado. It was sponsored by the National Heart Lung Blood Institute, the American Thoracic Society, the Colorado Biological Mass Spectrometry Society, and National Jewish Health. The goal of this workshop was to convene, for the first time, relevant experts in lung proteomics and metabolomics to discuss and overcome specific challenges in these fields that are unique to the lung. The main objectives of this workshop were to identify, review, and/or understand: (1) emerging technologies in metabolomics and proteomics as applied to the study of the lung; (2) the unique composition and challenges of lung-specific biological specimens for metabolomic and proteomic analysis; (3) the diverse informatics approaches and databases unique to metabolomics and proteomics, with special emphasis on the lung; (4) integrative platforms across genetic and genomic databases that can be applied to lung-related metabolomic and proteomic studies; and (5) the clinical applications of proteomics and metabolomics. The major findings and conclusions of this workshop are summarized at the end of the report, and outline the progress and challenges that face these rapidly advancing fields.

Real-time measurement of blood pressure with Nexfin in a patient with thalidomide-related phocomelia.

PubMed

Earle, Rosie; Vaghadia, Himat; Shanahan, Enda; Tang, Raymond; Sawka, Andrew

2016-11-01

We report the novel application of photoplethysmographic technology with the Nexfin HD monitor for real-time measurement of blood pressure (BP) in a patient with tetraamelia. The patient was a 58-year-old man with tetraamelia secondary to thalidomide exposure in utero, who presented for surgical excision of a maxillary schwannoma. Because difficulty of cuff use on rudimentary limbs and failure to gain invasive arterial access due to abnormalities of limb vasculature, this population is known to pose some unique challenges for BP measurement. Nexfin may offer an alternative noninvasive method to detect BP in patients with phocomelia during the perioperative period. Copyright © 2016 Elsevier Inc. All rights reserved.

Breast cancer brain metastases: evidence for neuronal-like adaptation in a ‘breast-to-brain’ transition?

PubMed Central

2014-01-01

Brain metastases remain a significant challenge in the treatment of breast cancer patients due to the unique environment posed by the central nervous system. A better understanding of the biology of breast cancer cells that have metastasized to the brain is required to develop improved therapies. A recent Proceedings of the National Academy of Sciences article demonstrates that breast cancer cells in the brain microenvironment express γ-aminobutyric acid (GABA)-related genes, enabling them to utilize GABA as an oncometabolite, thus gaining a proliferative advantage. In this viewpoint, we highlight these findings and their potential impact on the treatment of breast cancer brain metastases. PMID:25679873

Recent Advances on Inorganic Nanoparticle-Based Cancer Therapeutic Agents

PubMed Central

Wang, Fenglin; Li, Chengyao; Cheng, Jing; Yuan, Zhiqin

2016-01-01

Inorganic nanoparticles have been widely investigated as therapeutic agents for cancer treatments in biomedical fields due to their unique physical/chemical properties, versatile synthetic strategies, easy surface functionalization and excellent biocompatibility. This review focuses on the discussion of several types of inorganic nanoparticle-based cancer therapeutic agents, including gold nanoparticles, magnetic nanoparticles, upconversion nanoparticles and mesoporous silica nanoparticles. Several cancer therapy techniques are briefly introduced at the beginning. Emphasis is placed on how these inorganic nanoparticles can provide enhanced therapeutic efficacy in cancer treatment through site-specific accumulation, targeted drug delivery and stimulated drug release, with elaborations on several examples to highlight the respective strategies adopted. Finally, a brief summary and future challenges are included. PMID:27898016

Challenges in verification and validation of autonomous systems for space exploration

NASA Technical Reports Server (NTRS)

Brat, Guillaume; Jonsson, Ari

2005-01-01

Space exploration applications offer a unique opportunity for the development and deployment of autonomous systems, due to limited communications, large distances, and great expense of direct operation. At the same time, the risk and cost of space missions leads to reluctance to taking on new, complex and difficult-to-understand technology. A key issue in addressing these concerns is the validation of autonomous systems. In recent years, higher-level autonomous systems have been applied in space applications. In this presentation, we will highlight those autonomous systems, and discuss issues in validating these systems. We will then look to future demands on validating autonomous systems for space, identify promising technologies and open issues.

Arterial Spin Labeling: a one-stop-shop for measurement of brain perfusion in the clinical settings.

PubMed

Golay, Xavier; Petersen, Esben T; Zimine, Ivan; Lim, Tchoyoson C C

2007-01-01

Arterial Spin Labeling (ASL) has opened a unique window into the human brain function and perfusion physiology. Altogether fast and of intrinsic high spatial resolution, ASL is a technique very appealing not only for the diagnosis of vascular diseases, but also in basic neuroscience for the follow-up of small perfusion changes occurring during brain activation. However, due to limited signal-to-noise ratio and complex flow kinetics, ASL is one of the more challenging disciplines within magnetic resonance imaging. In this paper, the theoretical background and main implementations of ASL are revisited. In particular, the different uses of ASL, the pitfalls and possibilities are described and illustrated using clinical cases.

2D nanomaterials assembled from sequence-defined molecules

DOE PAGES

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

2017-10-21

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. Here, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. We also discuss the challenges andmore » opportunities in this new field.« less

2D nanomaterials assembled from sequence-defined molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. Here, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. We also discuss the challenges andmore » opportunities in this new field.« less

Going clean: structure and dynamics of peptides in the gas phase and paths to solvation.

PubMed

Baldauf, Carsten; Rossi, Mariana

2015-12-16

The gas phase is an artificial environment for biomolecules that has gained much attention both experimentally and theoretically due to its unique characteristic of providing a clean room environment for the comparison between theory and experiment. In this review we give an overview mainly on first-principles simulations of isolated peptides and the initial steps of their interactions with ions and solvent molecules: a bottom up approach to the complexity of biological environments. We focus on the accuracy of different methods to explore the conformational space, the connections between theory and experiment regarding collision cross section evaluations and (anharmonic) vibrational spectra, and the challenges faced in this field.

Recent Advances on Inorganic Nanoparticle-Based Cancer Therapeutic Agents.

PubMed

Wang, Fenglin; Li, Chengyao; Cheng, Jing; Yuan, Zhiqin

2016-11-25

Inorganic nanoparticles have been widely investigated as therapeutic agents for cancer treatments in biomedical fields due to their unique physical/chemical properties, versatile synthetic strategies, easy surface functionalization and excellent biocompatibility. This review focuses on the discussion of several types of inorganic nanoparticle-based cancer therapeutic agents, including gold nanoparticles, magnetic nanoparticles, upconversion nanoparticles and mesoporous silica nanoparticles. Several cancer therapy techniques are briefly introduced at the beginning. Emphasis is placed on how these inorganic nanoparticles can provide enhanced therapeutic efficacy in cancer treatment through site-specific accumulation, targeted drug delivery and stimulated drug release, with elaborations on several examples to highlight the respective strategies adopted. Finally, a brief summary and future challenges are included.

Research progress on trifluoromethyl-based radical reaction process

NASA Astrophysics Data System (ADS)

Song, Hao

2017-12-01

Due to the unique properties imparted by the trifluoromethyl group, such as high electron density and strong lipotropy, which effectively improve acidity, lipophilicity and metabolic stability of the molecule itself, trifluoromethyl-substituted organic compounds are becoming increasingly important as structural motifs in pharmaceuticals, agrochemicals and organic materials. In this review, we present several methods developed for the direct introduction of a trifluoromethyl group, beginning with its rich and storied history. Then the present article addresses mechanism and process in carbon-carbon bond forming reaction based on radical process which is divided into three parts according to the way of CF3 radical generation. Finally, challenges and opportunities of researches on trifluoromethylation reactions facing are prospected.

Wireless Metal Detection and Surface Coverage Sensing for All-Surface Induction Heating

PubMed Central

Kilic, Veli Tayfun; Unal, Emre; Demir, Hilmi Volkan

2016-01-01

All-surface induction heating systems, typically comprising small-area coils, face a major challenge in detecting the presence of a metallic vessel and identifying its partial surface coverage over the coils to determine which of the coils to power up. The difficulty arises due to the fact that the user can heat vessels made of a wide variety of metals (and their alloys). To address this problem, we propose and demonstrate a new wireless detection methodology that allows for detecting the presence of metallic vessels together with uniquely sensing their surface coverages while also identifying their effective material type in all-surface induction heating systems. The proposed method is based on telemetrically measuring simultaneously inductance and resistance of the induction coil coupled with the vessel in the heating system. Here, variations in the inductance and resistance values for an all-surface heating coil loaded by vessels (made of stainless steel and aluminum) at different positions were systematically investigated at different frequencies. Results show that, independent of the metal material type, unique identification of the surface coverage is possible at all freqeuncies. Additionally, using the magnitude and phase information extracted from the coupled coil impedance, unique identification of the vessel effective material is also achievable, this time independent of its surface coverage. PMID:26978367

Face recognition in the thermal infrared domain

NASA Astrophysics Data System (ADS)

Kowalski, M.; Grudzień, A.; Palka, N.; Szustakowski, M.

2017-10-01

Biometrics refers to unique human characteristics. Each unique characteristic may be used to label and describe individuals and for automatic recognition of a person based on physiological or behavioural properties. One of the most natural and the most popular biometric trait is a face. The most common research methods on face recognition are based on visible light. State-of-the-art face recognition systems operating in the visible light spectrum achieve very high level of recognition accuracy under controlled environmental conditions. Thermal infrared imagery seems to be a promising alternative or complement to visible range imaging due to its relatively high resistance to illumination changes. A thermal infrared image of the human face presents its unique heat-signature and can be used for recognition. The characteristics of thermal images maintain advantages over visible light images, and can be used to improve algorithms of human face recognition in several aspects. Mid-wavelength or far-wavelength infrared also referred to as thermal infrared seems to be promising alternatives. We present the study on 1:1 recognition in thermal infrared domain. The two approaches we are considering are stand-off face verification of non-moving person as well as stop-less face verification on-the-move. The paper presents methodology of our studies and challenges for face recognition systems in the thermal infrared domain.

GPU-BSM: A GPU-Based Tool to Map Bisulfite-Treated Reads

PubMed Central

Manconi, Andrea; Orro, Alessandro; Manca, Emanuele; Armano, Giuliano; Milanesi, Luciano

2014-01-01

Cytosine DNA methylation is an epigenetic mark implicated in several biological processes. Bisulfite treatment of DNA is acknowledged as the gold standard technique to study methylation. This technique introduces changes in the genomic DNA by converting cytosines to uracils while 5-methylcytosines remain nonreactive. During PCR amplification 5-methylcytosines are amplified as cytosine, whereas uracils and thymines as thymine. To detect the methylation levels, reads treated with the bisulfite must be aligned against a reference genome. Mapping these reads to a reference genome represents a significant computational challenge mainly due to the increased search space and the loss of information introduced by the treatment. To deal with this computational challenge we devised GPU-BSM, a tool based on modern Graphics Processing Units. Graphics Processing Units are hardware accelerators that are increasingly being used successfully to accelerate general-purpose scientific applications. GPU-BSM is a tool able to map bisulfite-treated reads from whole genome bisulfite sequencing and reduced representation bisulfite sequencing, and to estimate methylation levels, with the goal of detecting methylation. Due to the massive parallelization obtained by exploiting graphics cards, GPU-BSM aligns bisulfite-treated reads faster than other cutting-edge solutions, while outperforming most of them in terms of unique mapped reads. PMID:24842718

International Student Mental Health

ERIC Educational Resources Information Center

Prieto-Welch, Susan L.

2016-01-01

This chapter describes the mental health status of international students in institutions of higher education, unique challenges these students face and their impact on mental health, and suggestions for ways to address these challenges.

Pediatric reference intervals for alkaline phosphatase.

PubMed

Zierk, Jakob; Arzideh, Farhad; Haeckel, Rainer; Cario, Holger; Frühwald, Michael C; Groß, Hans-Jürgen; Gscheidmeier, Thomas; Hoffmann, Reinhard; Krebs, Alexander; Lichtinghagen, Ralf; Neumann, Michael; Ruf, Hans-Georg; Steigerwald, Udo; Streichert, Thomas; Rascher, Wolfgang; Metzler, Markus; Rauh, Manfred

2017-01-01

Interpretation of alkaline phosphatase activity in children is challenging due to extensive changes with growth and puberty leading to distinct sex- and age-specific dynamics. Continuous percentile charts from birth to adulthood allow accurate consideration of these dynamics and seem reasonable for an analyte as closely linked to growth as alkaline phosphatase. However, the ethical and practical challenges unique to pediatric reference intervals have restricted the creation of such percentile charts, resulting in limitations when clinical decisions are based on alkaline phosphatase activity. We applied an indirect method to generate percentile charts for alkaline phosphatase activity using clinical laboratory data collected during the clinical care of patients. A total of 361,405 samples from 124,440 patients from six German tertiary care centers and one German laboratory service provider measured between January 2004 and June 2015 were analyzed. Measurement of alkaline phosphatase activity was performed on Roche Cobas analyzers using the IFCC's photometric method. We created percentile charts for alkaline phosphatase activity in girls and boys from birth to 18 years which can be used as reference intervals. Additionally, data tables of age- and sex-specific percentile values allow the incorporation of these results into laboratory information systems. The percentile charts provided enable the appropriate differential diagnosis of changes in alkaline phosphatase activity due to disease and changes due to physiological development. After local validation, integration of the provided percentile charts into result reporting facilitates precise assessment of alkaline phosphatase dynamics in pediatrics.

BOLD magnetic resonance imaging in nephrology

PubMed Central

Hall, Michael E; Jordan, Jennifer H; Juncos, Luis A; Hundley, W Gregory; Hall, John E

2018-01-01

Magnetic resonance (MR) imaging, a non-invasive modality that provides anatomic and physiologic information, is increasingly used for diagnosis of pathophysiologic conditions and for understanding renal physiology in humans. Although functional MR imaging methods were pioneered to investigate the brain, they also offer powerful techniques for investigation of other organ systems such as the kidneys. However, imaging the kidneys provides unique challenges due to potential complications from contrast agents. Therefore, development of non-contrast techniques to study kidney anatomy and physiology is important. Blood oxygen level-dependent (BOLD) MR is a non-contrast imaging technique that provides functional information related to renal tissue oxygenation in various pathophysiologic conditions. Here we discuss technical considerations, clinical uses and future directions for use of BOLD MR as well as complementary MR techniques to better understand renal pathophysiology. Our intent is to summarize kidney BOLD MR applications for the clinician rather than focusing on the complex physical challenges that functional MR imaging encompasses; however, we briefly discuss some of those issues. PMID:29559807

Exploiting the unique regenerative capacity of the liver to underpin cell and gene therapy strategies for genetic and acquired liver disease.

PubMed

Logan, Grant J; de Alencastro, Gustavo; Alexander, Ian E; Yeoh, George C

2014-11-01

The number of genetic or acquired diseases of the liver treatable by organ transplantation is ever-increasing as transplantation techniques improve placing additional demands on an already limited organ supply. While cell and gene therapies are distinctly different modalities, they offer a synergistic alternative to organ transplant due to distinct architectural and physiological properties of the liver. The hepatic blood supply and fenestrated endothelial system affords relatively facile accessibility for cell and/or gene delivery. More importantly, however, the remarkable capacity of hepatocytes to proliferate and repopulate the liver creates opportunities for new treatments based on emerging technologies. This review will summarise current understanding of liver regeneration, describe clinical and experimental cell and gene therapeutic modalities and discuss critical challenges to translate these new technologies to wider clinical utility. This article is part of a Directed Issue entitled: "Regenerative Medicine: the challenge of translation". Copyright © 2014 Elsevier Ltd. All rights reserved.

Modular and Stochastic Approaches to Molecular Pathway Models of ATM, TGF beta, and WNT Signaling

NASA Technical Reports Server (NTRS)

Cucinotta, Francis A.; O'Neill, Peter; Ponomarev, Artem; Carra, Claudio; Whalen, Mary; Pluth, Janice M.

2009-01-01

Deterministic pathway models that describe the biochemical interactions of a group of related proteins, their complexes, activation through kinase, etc. are often the basis for many systems biology models. Low dose radiation effects present a unique set of challenges to these models including the importance of stochastic effects due to the nature of radiation tracks and small number of molecules activated, and the search for infrequent events that contribute to cancer risks. We have been studying models of the ATM, TGF -Smad and WNT signaling pathways with the goal of applying pathway models to the investigation of low dose radiation cancer risks. Modeling challenges include introduction of stochastic models of radiation tracks, their relationships to more than one substrate species that perturb pathways, and the identification of a representative set of enzymes that act on the dominant substrates. Because several pathways are activated concurrently by radiation the development of modular pathway approach is of interest.

SACRB-MAC: A High-Capacity MAC Protocol for Cognitive Radio Sensor Networks in Smart Grid

PubMed Central

Yang, Zhutian; Shi, Zhenguo; Jin, Chunlin

2016-01-01

The Cognitive Radio Sensor Network (CRSN) is considered as a viable solution to enhance various aspects of the electric power grid and to realize a smart grid. However, several challenges for CRSNs are generated due to the harsh wireless environment in a smart grid. As a result, throughput and reliability become critical issues. On the other hand, the spectrum aggregation technique is expected to play an important role in CRSNs in a smart grid. By using spectrum aggregation, the throughput of CRSNs can be improved efficiently, so as to address the unique challenges of CRSNs in a smart grid. In this regard, we proposed Spectrum Aggregation Cognitive Receiver-Based MAC (SACRB-MAC), which employs the spectrum aggregation technique to improve the throughput performance of CRSNs in a smart grid. Moreover, SACRB-MAC is a receiver-based MAC protocol, which can provide a good reliability performance. Analytical and simulation results demonstrate that SACRB-MAC is a promising solution for CRSNs in a smart grid. PMID:27043573

SACRB-MAC: A High-Capacity MAC Protocol for Cognitive Radio Sensor Networks in Smart Grid.

PubMed

Yang, Zhutian; Shi, Zhenguo; Jin, Chunlin

2016-03-31

The Cognitive Radio Sensor Network (CRSN) is considered as a viable solution to enhance various aspects of the electric power grid and to realize a smart grid. However, several challenges for CRSNs are generated due to the harsh wireless environment in a smart grid. As a result, throughput and reliability become critical issues. On the other hand, the spectrum aggregation technique is expected to play an important role in CRSNs in a smart grid. By using spectrum aggregation, the throughput of CRSNs can be improved efficiently, so as to address the unique challenges of CRSNs in a smart grid. In this regard, we proposed Spectrum Aggregation Cognitive Receiver-Based MAC (SACRB-MAC), which employs the spectrum aggregation technique to improve the throughput performance of CRSNs in a smart grid. Moreover, SACRB-MAC is a receiver-based MAC protocol, which can provide a good reliability performance. Analytical and simulation results demonstrate that SACRB-MAC is a promising solution for CRSNs in a smart grid.

Super-Resolution Microscopy: Shedding Light on the Cellular Plasma Membrane.

PubMed

Stone, Matthew B; Shelby, Sarah A; Veatch, Sarah L

2017-06-14

Lipids and the membranes they form are fundamental building blocks of cellular life, and their geometry and chemical properties distinguish membranes from other cellular environments. Collective processes occurring within membranes strongly impact cellular behavior and biochemistry, and understanding these processes presents unique challenges due to the often complex and myriad interactions between membrane components. Super-resolution microscopy offers a significant gain in resolution over traditional optical microscopy, enabling the localization of individual molecules even in densely labeled samples and in cellular and tissue environments. These microscopy techniques have been used to examine the organization and dynamics of plasma membrane components, providing insight into the fundamental interactions that determine membrane functions. Here, we broadly introduce the structure and organization of the mammalian plasma membrane and review recent applications of super-resolution microscopy to the study of membranes. We then highlight some inherent challenges faced when using super-resolution microscopy to study membranes, and we discuss recent technical advancements that promise further improvements to super-resolution microscopy and its application to the plasma membrane.

Sustainable Approaches for Materials Management in Remote, Economically Challenged Areas of the Pacific

EPA Science Inventory

Remote, economically challenged areas in the Commonwealth of the Northern Marianas Islands (CNMI) and American Samoa in the US Pacific island territories face unique challenges with respect to solid waste management. These islands are remote and isolated, with some islands suppo...

Coupling of Large Amplitude Inversion with Other States

NASA Astrophysics Data System (ADS)

Pearson, John; Yu, Shanshan

2016-06-01

The coupling of a large amplitude motion with a small amplitude vibration remains one of the least well characterized problems in molecular physics. Molecular inversion poses a few unique and not intuitively obvious challenges to the large amplitude motion problem. In spite of several decades of theoretical work numerous challenges in calculation of transition frequencies and more importantly intensities persist. The most challenging aspect of this problem is that the inversion coordinate is a unique function of the overall vibrational state including both the large and small amplitude modes. As a result, the r-axis system and the meaning of the K-quantum number in the rotational basis set are unique to each vibrational state of large or small amplitude motion. This unfortunate reality has profound consequences to calculation of intensities and the coupling of nearly degenerate vibrational states. The case of NH3 inversion and inversion through a plane of symmetry in alcohols will be examined to find a general path forward.

Mixture model normalization for non-targeted gas chromatography/mass spectrometry metabolomics data.

PubMed

Reisetter, Anna C; Muehlbauer, Michael J; Bain, James R; Nodzenski, Michael; Stevens, Robert D; Ilkayeva, Olga; Metzger, Boyd E; Newgard, Christopher B; Lowe, William L; Scholtens, Denise M

2017-02-02

Metabolomics offers a unique integrative perspective for health research, reflecting genetic and environmental contributions to disease-related phenotypes. Identifying robust associations in population-based or large-scale clinical studies demands large numbers of subjects and therefore sample batching for gas-chromatography/mass spectrometry (GC/MS) non-targeted assays. When run over weeks or months, technical noise due to batch and run-order threatens data interpretability. Application of existing normalization methods to metabolomics is challenged by unsatisfied modeling assumptions and, notably, failure to address batch-specific truncation of low abundance compounds. To curtail technical noise and make GC/MS metabolomics data amenable to analyses describing biologically relevant variability, we propose mixture model normalization (mixnorm) that accommodates truncated data and estimates per-metabolite batch and run-order effects using quality control samples. Mixnorm outperforms other approaches across many metrics, including improved correlation of non-targeted and targeted measurements and superior performance when metabolite detectability varies according to batch. For some metrics, particularly when truncation is less frequent for a metabolite, mean centering and median scaling demonstrate comparable performance to mixnorm. When quality control samples are systematically included in batches, mixnorm is uniquely suited to normalizing non-targeted GC/MS metabolomics data due to explicit accommodation of batch effects, run order and varying thresholds of detectability. Especially in large-scale studies, normalization is crucial for drawing accurate conclusions from non-targeted GC/MS metabolomics data.

Parallel Comparison of N-Linked Glycopeptide Enrichment Techniques Reveals Extensive Glycoproteomic Analysis of Plasma Enabled by SAX-ERLIC.

PubMed

Totten, Sarah M; Feasley, Christa L; Bermudez, Abel; Pitteri, Sharon J

2017-03-03

Protein glycosylation is of increasing interest due to its important roles in protein function and aberrant expression with disease. Characterizing protein glycosylation remains analytically challenging due to its low abundance, ion suppression issues, and microheterogeneity at glycosylation sites, especially in complex samples such as human plasma. In this study, the utility of three common N-linked glycopeptide enrichment techniques is compared using human plasma. By analysis on an LTQ-Orbitrap Elite mass spectrometer, electrostatic repulsion hydrophilic interaction liquid chromatography using strong anion exchange solid-phase extraction (SAX-ERLIC) provided the most extensive N-linked glycopeptide enrichment when compared with multilectin affinity chromatography (M-LAC) and Sepharose-HILIC enrichments. SAX-ERLIC enrichment yielded 191 unique glycoforms across 72 glycosylation sites from 48 glycoproteins, which is more than double that detected using other enrichment techniques. The greatest glycoform diversity was observed in SAX-ERLIC enrichment, with no apparent bias toward specific glycan types. SAX-ERLIC enrichments were additionally analyzed by an Orbitrap Fusion Lumos mass spectrometer to maximize glycopeptide identifications for a more comprehensive assessment of protein glycosylation. In these experiments, 829 unique glycoforms were identified across 208 glycosylation sites from 95 plasma glycoproteins, a significant improvement from the initial method comparison and one of the most extensive site-specific glycosylation analysis in immunodepleted human plasma to date. Data are available via ProteomeXchange with identifier PXD005655.

Viral infections in transplant recipients.

PubMed

Razonable, R R; Eid, A J

2009-12-01

Solid organ and hematopoietic stem cell transplant recipients are uniquely predisposed to develop clinical illness, often with increased severity, due to a variety of common and opportunistic viruses. Patients may acquire viral infections from the donor (donor-derived infections), from reactivation of endogenous latent virus, or from the community. Herpes viruses, most notably cytomegalovirus and Epstein Barr virus, are the most common among opportunistic viral pathogens that cause infection after solid organ and hematopoietic stem cell transplantation. The polyoma BK virus causes opportunistic clinical syndromes predominantly in kidney and allogeneic hematopoietic stem cell transplant recipients. The agents of viral hepatitis B and C present unique challenges particularly among liver transplant recipients. Respiratory viral illnesses due to influenza, respiratory syncytial virus, and parainfluenza virus may affect all types of transplant recipients, although severe clinical disease is observed more commonly among lung and allogeneic hematopoietic stem cell transplant recipients. Less common viral infections affecting transplant recipients include those caused by adenoviruses, parvovirus B19, and West Nile virus. Treatment for viruses with proven effective antiviral drug therapies should be complemented by reduction in the degree of immunosuppression. For others with no proven antiviral drugs for therapy, reduction in the degree of immunosuppression remains as the sole effective strategy for management. Prevention of viral infections is therefore of utmost importance, and this may be accomplished through vaccination, antiviral strategies, and aggressive infection control measures.

Unique Approach to Dental Management of Children with Hearing Impairment.

PubMed

Renahan, Navanith; Varma, R Balagopal; Kumaran, Parvathy; Xavier, Arun M

2017-01-01

The number of deaf children has dramatically increased in the past few decades. These children present to the pediatric dentist a unique set of challenges mostly pertaining to the establishment of communication with them. There have been very few attempts in the past to break down these challenges and formulate a strategy on how to manage them effectively. This is a case report of a child who was successfully managed using two different modes of communication. Finally, the advantages and disadvantages are mentioned, and a common strategy incorporating the positives of both the methods has been devised. Renahan N, Varma RB, Kumaran P, Xavier AM. Unique Approach to Dental Management of Children with Hearing Impairment. Int J Clin Pediatr Dent 2017;10(1):107-110.

Practical Considerations and Challenges Involved in Surfactant Enhanced Bioremediation of Oil

PubMed Central

Mohanty, Sagarika; Jasmine, Jublee

2013-01-01

Surfactant enhanced bioremediation (SEB) of oil is an approach adopted to overcome the bioavailability constraints encountered in biotransformation of nonaqueous phase liquid (NAPL) pollutants. Fuel oils contain n-alkanes and other aliphatic hydrocarbons, monoaromatics, and polynuclear aromatic hydrocarbons (PAHs). Although hydrocarbon degrading cultures are abundant in nature, complete biodegradation of oil is rarely achieved even under favorable environmental conditions due to the structural complexity of oil and culture specificities. Moreover, the interaction among cultures in a consortium, substrate interaction effects during the degradation and ability of specific cultures to alter the bioavailability of oil invariably affect the process. Although SEB has the potential to increase the degradation rate of oil and its constituents, there are numerous challenges in the successful application of this technology. Success is dependent on the choice of appropriate surfactant type and dose since the surfactant-hydrocarbon-microorganism interaction may be unique to each scenario. Surfactants not only enhance the uptake of constituents through micellar solubilization and emulsification but can also alter microbial cell surface characteristics. Moreover, hydrocarbons partitioned in micelles may not be readily bioavailable depending on the microorganism-surfactant interactions. Surfactant toxicity and inherent biodegradability of surfactants may pose additional challenges as discussed in this review. PMID:24350261

A predictive machine learning approach for microstructure optimization and materials design

NASA Astrophysics Data System (ADS)

Liu, Ruoqian; Kumar, Abhishek; Chen, Zhengzhang; Agrawal, Ankit; Sundararaghavan, Veera; Choudhary, Alok

2015-06-01

This paper addresses an important materials engineering question: How can one identify the complete space (or as much of it as possible) of microstructures that are theoretically predicted to yield the desired combination of properties demanded by a selected application? We present a problem involving design of magnetoelastic Fe-Ga alloy microstructure for enhanced elastic, plastic and magnetostrictive properties. While theoretical models for computing properties given the microstructure are known for this alloy, inversion of these relationships to obtain microstructures that lead to desired properties is challenging, primarily due to the high dimensionality of microstructure space, multi-objective design requirement and non-uniqueness of solutions. These challenges render traditional search-based optimization methods incompetent in terms of both searching efficiency and result optimality. In this paper, a route to address these challenges using a machine learning methodology is proposed. A systematic framework consisting of random data generation, feature selection and classification algorithms is developed. Experiments with five design problems that involve identification of microstructures that satisfy both linear and nonlinear property constraints show that our framework outperforms traditional optimization methods with the average running time reduced by as much as 80% and with optimality that would not be achieved otherwise.

Drugs in development for toxoplasmosis: advances, challenges, and current status.

PubMed

Alday, P Holland; Doggett, Joseph Stone

2017-01-01

Toxoplasma gondii causes fatal and debilitating brain and eye diseases. Medicines that are currently used to treat toxoplasmosis commonly have toxic side effects and require prolonged courses that range from weeks to more than a year. The need for long treatment durations and the risk of relapsing disease are in part due to the lack of efficacy against T. gondii tissue cysts. The challenges for developing a more effective treatment for toxoplasmosis include decreasing toxicity, achieving therapeutic concentrations in the brain and eye, shortening duration, eliminating tissue cysts from the host, safety in pregnancy, and creating a formulation that is inexpensive and practical for use in resource-poor areas of the world. Over the last decade, significant progress has been made in identifying and developing new compounds for the treatment of toxoplasmosis. Unlike clinically used medicines that were repurposed for toxoplasmosis, these compounds have been optimized for efficacy against toxoplasmosis during preclinical development. Medicines with enhanced efficacy as well as features that address the unique aspects of toxoplasmosis have the potential to greatly improve toxoplasmosis therapy. This review discusses the facets of toxoplasmosis that are pertinent to drug design and the advances, challenges, and current status of preclinical drug research for toxoplasmosis.

Drugs in development for toxoplasmosis: advances, challenges, and current status

PubMed Central

Alday, P Holland; Doggett, Joseph Stone

2017-01-01

Toxoplasma gondii causes fatal and debilitating brain and eye diseases. Medicines that are currently used to treat toxoplasmosis commonly have toxic side effects and require prolonged courses that range from weeks to more than a year. The need for long treatment durations and the risk of relapsing disease are in part due to the lack of efficacy against T. gondii tissue cysts. The challenges for developing a more effective treatment for toxoplasmosis include decreasing toxicity, achieving therapeutic concentrations in the brain and eye, shortening duration, eliminating tissue cysts from the host, safety in pregnancy, and creating a formulation that is inexpensive and practical for use in resource-poor areas of the world. Over the last decade, significant progress has been made in identifying and developing new compounds for the treatment of toxoplasmosis. Unlike clinically used medicines that were repurposed for toxoplasmosis, these compounds have been optimized for efficacy against toxoplasmosis during preclinical development. Medicines with enhanced efficacy as well as features that address the unique aspects of toxoplasmosis have the potential to greatly improve toxoplasmosis therapy. This review discusses the facets of toxoplasmosis that are pertinent to drug design and the advances, challenges, and current status of preclinical drug research for toxoplasmosis. PMID:28182168

Rotorcraft Health Management Issues and Challenges

NASA Technical Reports Server (NTRS)

Zakrajsek, James J.; Dempsey, Paula J.; Huff, Edward M.; Augustin, Michael; Safa-Bakhsh, Robab; Ephraim, Piet; Grabil, Paul; Decker, Harry J.

2006-01-01

This paper presents an overview of health management issues and challenges that are specific to rotorcraft. Rotorcraft form a unique subset of air vehicles in that their propulsion system is used not only for propulsion, but also serves as the primary source of lift and maneuvering of the vehicle. No other air vehicle relies on the propulsion system to provide these functions through a transmission system with single critical load paths without duplication or redundancy. As such, health management of the power train is a critical and unique part of any rotorcraft health management system. This paper focuses specifically on the issues and challenges related to the dynamic mechanical components in the main power train. This includes the transmission and main rotor mechanisms. This paper will review standard practices used for rotorcraft health management, lessons learned from fielded trials, and future challenges.

Medical Operational Challenges in the Expedition 16 Landing and Recovery

NASA Technical Reports Server (NTRS)

Moynihan, S.; Johnston, S. L.; Ilcus, L. S.; Shevchenko, V.

2009-01-01

On April 19, 2008 the crew of Expedition 16 left the International Space Station and returned to earth via their Soyuz TMA-11 capsule after 192 days on orbit. Their capsule experienced the second consecutive and third ballistic reentry in the last 10 TMA recoveries and landed approximately 260 miles (420 km) from the prime landing site. Issues: The purpose of this presentation will be to describe, not only the typical medical operational challenges faced by Flight Surgeons recovering a long duration crew from space, but also address the unique challenges that existed with the Expedition 16 landing and crew recovery. Nominal Soyuz recovery challenges include remote recovery sites with crew exposures to sleep shifting and fatigue, dehydration, hypothermia and hyperthermia, and rotational, sustained, and impact g-forces. These environmental factors coupled with the patho-physiologic neuro-vestibular and orthostatic intolerance changes that occur secondary to the crews reintroduction into the earth s gravity field will be detailed. Additional challenges that were unique to this expedition included a ballistic reentry with higher g-loads, the presence of fire outside of the capsule on landing, a contingency medical event of a ground support personnel, and loss of communications with the crew just prior to landing and during recovery operations. Conclusions: In spite of these unique challenges the Russian Search and Rescue Forces and Medical Support personnel along with U.S. Medical Support performed well together. Possible improvements in training and coordination will be discussed.

Supporting Middle School Students Whose Parents Are Deployed: Challenges and Strategies for Schools

ERIC Educational Resources Information Center

Williams, Brenda

2013-01-01

Middle school students from military families face unique challenges, especially when their parents are deployed. Among the challenges they experience are frequent relocations; issues that affect academic achievement; uncertainty; and changes in roles, responsibilities, and relationships at home. Reunification involves issues of the returning…

Essential Tensions in Interdisciplinary Scholarship: Navigating Challenges in Affect, Epistemologies, and Structure in Environment-Society Research Centers

ERIC Educational Resources Information Center

Turner, V. Kelly; Benessaiah, Karina; Warren, Scott; Iwaniec, David

2015-01-01

Scholars have enumerated unique challenges to collaborative interdisciplinary research, many of which evade prescriptive solutions. Some of these challenges can be understood as "essential tensions," necessary and persistent contradictory imperatives in the scientific process. Drawing from interviews with internationally renowned…

Student Media Production to Meet Challenges in Climate Change Science Education

ERIC Educational Resources Information Center

Rooney-Varga, Juliette N.; Brisk, Angelica Allende; Adams, Elizabeth; Shuldman, Elizabeth; Rath, Kenneth

2014-01-01

While the need for effective climate change education is growing, this area of geoscience also poses unique educational challenges. These challenges include the politicization of climate change, the psychological and affective responses it elicits, and common misconceptions, which can all create barriers to learning. Here, we present an…

NASA Space Rocket Logistics Challenges

NASA Technical Reports Server (NTRS)

Bramon, Chris; Neeley, James R.; Jones, James V.; Watson, Michael D.; Inman, Sharon K.; Tuttle, Loraine

2014-01-01

The Space Launch System (SLS) is the new NASA heavy lift launch vehicle in development and is scheduled for its first mission in 2017. SLS has many of the same logistics challenges as any other large scale program. However, SLS also faces unique challenges. This presentation will address the SLS challenges, along with the analysis and decisions to mitigate the threats posed by each.

Mass Spectrometry for Planetary Probes: Past, Present and Future

NASA Technical Reports Server (NTRS)

Niemann, Hasso B.; Harpold, Dan N.; Jamieson, Brian G.; Mahaffy, Paul R.

2005-01-01

Atmospheric entry probes present a unique opportunity for performing quantitative analysis of extra-terrestrial atmospheres in cases where remote sensing alone may not be sufficient and measurements with balloons or aircraft is not practical. An entry probe can provide a complete vertical profile of atmospheric parameters including chemical composition, which cannot be obtained with most other techniques. There are, however, unique challenges associated with building instruments for an entry probe, as compared to orbiters, landers, or rovers. Conditions during atmospheric entry are extreme, there are inherent time constraints due to the short duration of the experiment, and the instrument experiences rapid environmental changes in temperature and pressure as it descends. In addition, there are resource limitations, i.e. mass, power, size and bandwidth. Finally, the demands on the instrument design are determined in large part by conditions (pressure, temperature, composition) unique to the particular body under study, and as a result there is no one-size-fits-all instrument for an atmospheric probe. Many of these requirements can be more easily met by miniaturizing the probe instrument. Our experience building mass spectrometers for atmospheric entry probes leads us to believe that the time is right for a fundamental change in the way spaceflight mass spectrometers are built. The emergence over the past twenty years of Micro-electro- mechanical Systems (MEMS), utilizing lithographic semiconductor fabrication techniques to produce instrument systems in miniature, holds great promise for application to spaceflight mass spectrometry. A highly miniaturized, high performance and low-power mass spectrometer would be an enormous benefit to future entry probe missions, allowing, for example, parallel measurements (e.g., multiple simultaneous gas chromatographic analyses and direct atmospheric leaks.) Such an instrument would also enable mass spectrometry on board small multiple entry probes. In the development of a MEMS Mass Spectrometer, the challenge facing us is to move beyond the proof-of-concept, where research dollars tend to focus, and carry out the detailed work of developing a high performance mass spectrometer system on a chip which meets the unique technical requirements for an atmospheric entry probe described above.

A narrative literature review of depression following traumatic brain injury: prevalence, impact, and management challenges.

PubMed

Juengst, Shannon B; Kumar, Raj G; Wagner, Amy K

2017-01-01

Depression is one of the most common conditions to emerge after traumatic brain injury (TBI), and despite its potentially serious consequences it remains undertreated. Treatment for post-traumatic depression (PTD) is complicated due to the multifactorial etiology of PTD, ranging from biological pathways to psychosocial adjustment. Identifying the unique, personalized factors contributing to the development of PTD could improve long-term treatment and management for individuals with TBI. The purpose of this narrative literature review was to summarize the prevalence and impact of PTD among those with moderate to severe TBI and to discuss current challenges in its management. Overall, PTD has an estimated point prevalence of 30%, with 50% of individuals with moderate to severe TBI experiencing an episode of PTD in the first year after injury alone. PTD has significant implications for health, leading to more hospitalizations and greater caregiver burden, for participation, reducing rates of return to work and affecting social relationships, and for quality of life. PTD may develop directly or indirectly as a result of biological changes after injury, most notably post-injury inflammation, or through psychological and psychosocial factors, including pre injury personal characteristics and post-injury adjustment to disability. Current evidence for effective treatments is limited, although the strongest evidence supports antidepressants and cognitive behavioral interventions. More personalized approaches to treatment and further research into unique therapy combinations may improve the management of PTD and improve the health, functioning, and quality of life for individuals with TBI.

Engineering graphene and TMDs based van der Waals heterostructures for photovoltaic and photoelectrochemical solar energy conversion.

PubMed

Li, Changli; Cao, Qi; Wang, Faze; Xiao, Yequan; Li, Yanbo; Delaunay, Jean-Jacques; Zhu, Hongwei

2018-05-08

Graphene and two-dimensional (2D) transition metal dichalcogenides (TMDs) have attracted significant interest due to their unique properties that cannot be obtained in their bulk counterparts. These atomically thin 2D materials have demonstrated strong light-matter interactions, tunable optical bandgap structures and unique structural and electrical properties, rendering possible the high conversion efficiency of solar energy with a minimal amount of active absorber material. The isolated 2D monolayer can be stacked into arbitrary van der Waals (vdWs) heterostructures without the need to consider lattice matching. Several combinations of 2D/3D and 2D/2D materials have been assembled to create vdWs heterojunctions for photovoltaic (PV) and photoelectrochemical (PEC) energy conversion. However, the complex, less-constrained, and more environmentally vulnerable interface in a vdWs heterojunction is different from that of a conventional, epitaxially grown heterojunction, engendering new challenges for surface and interface engineering. In this review, the physics of band alignment, the chemistry of surface modification and the behavior of photoexcited charge transfer at the interface during PV and PEC processes will be discussed. We will present a survey of the recent progress and challenges of 2D/3D and 2D/2D vdWs heterojunctions, with emphasis on their applicability to PV and PEC devices. Finally, we will discuss emerging issues yet to be explored for 2D materials to achieve high solar energy conversion efficiency and possible strategies to improve their performance.

Electroluminescence and electrical degradation of insulating polymers at electrode interfaces under divergent fields

NASA Astrophysics Data System (ADS)

Zhang, Shuai; Li, Qi; Hu, Jun; Zhang, Bo; He, Jinliang

2018-04-01

Electrical degradation of insulating polymers at electrode interfaces is an essential factor in determining long-term reliability. A critical challenge is that the exact mechanism of degradation is not fully understood, either experimentally or theoretically, due to the inherent complex processes. Consequently, in this study, we investigate electroluminescence (EL) at the interface of an electrode and insulator, and determine the relationship between EL and electrical degradation. Using a tip-plate electrode structure, the unique features of EL under a highly divergent field are investigated. The voltage type (alternating or direct current), the polymer matrix, and the time of pressing are also investigated separately. A study of EL from insulators under a divergent field is provided, and the relationship between EL spectra and degradation is discussed. It is shown that EL spectra under a divergent field have unique characteristics compared with EL spectra from polymer films under a uniform field and the most obvious one is the UV emission. The results obtained in the current investigation bring us a step closer to understanding the process of electrical degradation and provide a potential way to diagnose insulator defects.

Innovative pharmaceutical development based on unique properties of nanoscale delivery formulation

PubMed Central

Mozhi, Anbu; Zhang, Xu; Zhao, Yuanyuan; Xue, Xiangdong; Hao, Yanli; Zhang, Xiaoning; Wang, Paul C.; Liang, Xing-Jie

2014-01-01

The advent of nanotechnology has reignited interest in the field of pharmaceutical science for the development of nanomedicine. Nanomedicinal formulations are nanometer-sized carrier materials designed for increasing the drug tissue bioavailability, thereby improving the treatment of systemically applied chemotherapeutic drugs. Nanomedicine is a new approach to deliver the pharmaceuticals through different routes of administration with safer and more effective therapies compared to conventional methods. To date, various kinds of nanomaterials have been developed over the years to make delivery systems more effective for the treatment of various diseases. Even though nanomaterials have significant advantages due to their unique nanoscale properties, there are still significant challenges in the improvement and development of nanoformulations with composites and other materials. Here in this review, we highlight the nanomedicinal formulations aiming to improve the balance between the efficacy and the toxicity of therapeutic interventions through different routes of administration and how to design nanomedicine for safer and more effective ways to improve the treatment quality. We also emphasize the environmental and health prospects of nanomaterials for human health care. PMID:23860639

Essential Role of Lymph Nodes in Contact Hypersensitivity Revealed in Lymphotoxin-α–Deficient Mice

PubMed Central

Rennert, Paul D.; Hochman, Paula S.; Flavell, Richard A.; Chaplin, David D.; Jayaraman, Sundararajan; Browning, Jeffrey L.; Fu, Yang-Xin

2001-01-01

Lymph nodes (LNs) are important sentinal organs, populated by circulating lymphocytes and antigen-bearing cells exiting the tissue beds. Although cellular and humoral immune responses are induced in LNs by antigenic challenge, it is not known if LNs are essential for acquired immunity. We examined immune responses in mice that lack LNs due to genetic deletion of lymphotoxin ligands or in utero blockade of membrane lymphotoxin. We report that LNs are absolutely required for generating contact hypersensitivity, a T cell–dependent cellular immune response induced by epicutaneous hapten. We show that the homing of epidermal Langerhans cells in response to hapten application is specifically directed to LNs, providing a cellular basis for this unique LN function. In contrast, the spleen cannot mediate contact hypersensitivity because antigen-bearing epidermal Langerhans cells do not access splenic white pulp. Finally, we formally demonstrate that LNs provide a unique environment essential for generating this acquired immune response by reversing the LN defect in lymphotoxin-α−/− mice, thereby restoring the capacity for contact hypersensitivity. PMID:11390430

β-Cell Autophagy in Diabetes Pathogenesis.

PubMed

Marasco, Michelle R; Linnemann, Amelia K

2018-05-01

Nearly 100 years have passed since Frederick Banting and Charles Best first discovered and purified insulin. Their discovery and subsequent improvements revolutionized the treatment of diabetes, and the field continues to move at an ever-faster pace with respect to unique treatments for both type 1 and type 2 diabetes. Despite these advances, we still do not fully understand how apoptosis of the insulin-producing β-cells is triggered, presenting a challenge in the development of preventative measures. In recent years, the process of autophagy has generated substantial interest in this realm due to discoveries highlighting its clear role in the maintenance of cellular homeostasis. As a result, the number of studies focused on islet and β-cell autophagy has increased substantially in recent years. In this review, we will discuss what is currently known regarding the role of β-cell autophagy in type 1 and type 2 diabetes pathogenesis, with an emphasis on new and exciting developments over the past 5 years. Further, we will discuss how these discoveries might be translated into unique treatments in the coming years.

Self‐Assembled Graphene‐Based Architectures and Their Applications

PubMed Central

Yuan, Zhongke; Xiao, Xiaofen; Li, Jing; Zhao, Zhe

2017-01-01

Abstract Due to unique planar structures and remarkable thermal, electronic, and mechanical properties, chemically modified graphenes (CMGs) such as graphene oxides, reduced graphene oxides, and the related derivatives are recognized as the attractive building blocks for “bottom‐up” nanotechnology, while self‐assembly of CMGs has emerged as one of the most promising approaches to construct advanced functional materials/systems based on graphene. By virtue of a variety of noncovalent forces like hydrogen bonding, van der Waals interaction, metal‐to‐ligand bonds, electrostatic attraction, hydrophobic–hydrophilic interactions, and π–π interactions, the CMGs bearing various functional groups are highly desirable for the assemblies with themselves and a variety of organic and/or inorganic species which can yield various hierarchical nanostructures and macroscopic composites endowed with unique structures, properties, and functions for widespread technological applications such as electronics, optoelectronics, electrocatalysis/photocatalysis, environment, and energy storage and conversion. In this review, significant recent advances concerning the self‐assembly of CMGs are summarized, and the broad applications of self‐assembled graphene‐based materials as well as some future opportunities and challenges in this vibrant area are elucidated. PMID:29619311

Capacity improvement of the carbon-based electrochemical capacitor by zigzag-edge introduced graphene

NASA Astrophysics Data System (ADS)

Tamura, Naoki; Tomai, Takaaki; Oka, Nobuto; Honma, Itaru

2018-01-01

The electrochemical properties of graphene edge has been attracted much attention. Especially, zigzag edge has high electrochemical activity because neutral radical exits on edge. However, due to a lack of efficient production method for zigzag graphene, the electrochemical properties of zigzag edge have not been experimentally demonstrated and the capacitance enhancement of carbonaceous materials in energy storage devices by the control in their edge states is still challenge. In this study, we fabricated zigzag-edge-rich graphene by a one-step method combining graphene exfoliation in supercritical fluid and anisotropic etching by catalytic nanoparticles. This efficient production of zigzag-edge-rich graphene allows us to investigate the electrochemical activity of zigzag edge. By cyclic voltammetry, we revealed the zigzag edge-introduced graphene exhibited unique redox reaction in aqueous acid solution. Moreover, by the calculation on the density function theory (DFT), this unique redox potential for zigzag edge-introduced graphene can be attributed to the proton-insertion/-extraction reactions at the zigzag edge. This finding indicates that the graphene edge modification can contribute to the further increase in the capacitance of the carbon-based electrochemical capacitor.

Innovative pharmaceutical development based on unique properties of nanoscale delivery formulation

NASA Astrophysics Data System (ADS)

Kumar, Anil; Chen, Fei; Mozhi, Anbu; Zhang, Xu; Zhao, Yuanyuan; Xue, Xiangdong; Hao, Yanli; Zhang, Xiaoning; Wang, Paul C.; Liang, Xing-Jie

2013-08-01

The advent of nanotechnology has reignited interest in the field of pharmaceutical science for the development of nanomedicine. Nanomedicinal formulations are nanometer-sized carrier materials designed for increasing the drug tissue bioavailability, thereby improving the treatment of systemically applied chemotherapeutic drugs. Nanomedicine is a new approach to deliver the pharmaceuticals through different routes of administration with safer and more effective therapies compared to conventional methods. To date, various kinds of nanomaterials have been developed over the years to make delivery systems more effective for the treatment of various diseases. Even though nanomaterials have significant advantages due to their unique nanoscale properties, there are still significant challenges in the improvement and development of nanoformulations with composites and other materials. Here in this review, we highlight the nanomedicinal formulations aiming to improve the balance between the efficacy and the toxicity of therapeutic interventions through different routes of administration and how to design nanomedicine for safer and more effective ways to improve the treatment quality. We also emphasize the environmental and health prospects of nanomaterials for human health care.

Challenges for Novice School Leaders: Facing Today's Issues in School Administration

ERIC Educational Resources Information Center

Beam, Andrea P.; Claxton, Russell L.; Smith, Samuel J.

2016-01-01

Challenges for novice school leaders evolve as information is managed differently and as societal and regulatory expectations change. This study addresses unique challenges faced by practicing school administrators (n = 159) during their first three years in a school leadership position. It focuses on their perceptions, how perceptions of present…

Showing Your Students You Care: Seeing the Individual Trees in the Classroom Forest

ERIC Educational Resources Information Center

Philipp, Randolph A.; Thanheiser, Eva

2010-01-01

Teaching is a complex profession, and although every context is unique, teachers face common challenges. The authors have identified two challenges that nearly every teacher encounters: (1) managing a classroom of students; and (2) addressing the needs of individual students. Although these are not teachers' only challenges, the authors highlight…

Postsecondary Strengths, Challenges, and Supports Experienced by Foster Care Alumni College Graduates

ERIC Educational Resources Information Center

Salazar, Amy M.; Jones, Kevin R.; Emerson, John C.; Mucha, Lauren

2016-01-01

Young people transitioning from foster care to college experience unique identities and circumstances that make being successful in college especially challenging. We used qualitative survey data from 248 college graduates who were formerly in foster care to explore the strengths, challenges, and supports they experienced while in college that…

Understanding Diversity of English Language Learners: Identification of ELLs and ELLs with Disabilities

ERIC Educational Resources Information Center

Wang, Charity

2014-01-01

English Language Learners (ELLs) are one of the fastest growing student populations throughout the country. With ELLs come unique challenges schools must navigate to best serve these students. One challenge is the identification of these students and proper placement and service within ELL programs offered by schools. Another challenge is…

Ethical Challenges of Military Social Workers Serving in a Combat Zone

ERIC Educational Resources Information Center

Simmons, Catherine A.; Rycraft, Joan R.

2010-01-01

Often faced with ethical challenges that may appear extraordinary, military social workers comprise a distinctive subgroup of the social work profession. From the unique paradigms in which they practice their craft, obvious questions about how military social workers address the ethical challenges inherent to their wartime mission arise. Using a…

NASA Space Flight Vehicle Fault Isolation Challenges

NASA Technical Reports Server (NTRS)

Neeley, James R.; Jones, James V.; Bramon, Christopher J.; Inman, Sharon K.; Tuttle, Loraine

2016-01-01

The Space Launch System (SLS) is the new NASA heavy lift launch vehicle in development and is scheduled for its first mission in 2018.SLS has many of the same logistics challenges as any other large scale program. However, SLS also faces unique challenges related to testability. This presentation will address the SLS challenges for diagnostics and fault isolation, along with the analyses and decisions to mitigate risk..

Unique research challenges for high-speed civil transports

NASA Technical Reports Server (NTRS)

Jackson, Charlie M., Jr.; Morris, E. K., Jr.

1988-01-01

Market growth and technological advances are expected to lead to a generation of long-range transports that cruise at supersonic or even hypersonic speeds. Current NASA/industry studies will define the market windows in terms of time frame, Mach number, and technology requirements for these aircraft. Initial results indicate that, for the years 2000 to 2020, economically attractive vehicles could have a cruise speed up to Mach 6. The resulting research challenges are unique. They must be met with technologies that will produce commercially successful and environmentally compatible vehicles where none have existed. Several important areas of research were identified for the high-speed civil transports. Among these are sonic boom, takeoff noise, thermal management, lightweight structures with long life, unique propulsion concepts, unconventional fuels, and supersonic laminar flow.

Unique research challenges for high-speed civil transports

NASA Technical Reports Server (NTRS)

Jackson, Charlie M., Jr.; Morris, Charles E. K., Jr.

1987-01-01

Market growth and technological advances are expected to lead to a generation of long-range transports that cruise at supersonic or even hypersonic speeds. Current NASA/industry studies will define the market windows in terms of time frame, Mach number, and technology requirements for these aircraft. Initial results indicate that, for the years 2000 to 2020, economically attractive vehicles could have a cruise speed up to Mach 6. The resulting research challenges are unique. They must be met with technologies that will produce commercially successful and environmentally compatible vehicles where none have existed. Several important areas of research were identified for the high-speed civil transports. Among these are sonic boom, takeoff noise, thermal management, lightweight structures with long life, unique propulsion concepts, unconventional fuels, and supersonic laminar flow.

Challenges of Applying a Comprehensive Model of Intervention Fidelity

PubMed Central

Bosak, Kelly; Pozehl, Bunny; Yates, Bernice

2014-01-01

Applying a comprehensive model of fidelity to interventions delivered by Information and Communication Technology (ICT) has multiple challenges. Fidelity must be considered in the design, implementation, evaluation, and reporting of the intervention. The fidelity strategies must address the unique aspects of the technology, including training providers to instruct participants to use the technology and to provide standardized feedback, rather than deliver the intervention in-person. Other challenges include the nonspecific effects resulting from participants accessing unintended content in interventions delivered by the Internet. ICT allows participant receipt and enactment of intervention skills to be assessed by electronic evidence, rather than in-person observation. Interventions using ICT, such as the Internet are unique, and there is less control of participant interaction with various electronic components. Monitoring participant use and providing standardized feedback for receipt and enactment of intervention skills is key to ensuring intervention fidelity. The final challenges involve evaluating and reporting fidelity. PMID:21474676

Resilient and Corrosion-proof Rolling Element Bearings Made from Ni-ti Alloys for Aerospace Mechanism Applications and the Ultimate Space Technology Development Platform

NASA Technical Reports Server (NTRS)

Dellacorte, Christopher

2014-01-01

The International Space Station provides a unique microgravity laboratory environment for research. The ISS also serves as an effective platform for the development of technologies and engineered solutions related to living and working in space. The space environment also challenges our capabilities related to lubrication and tribology. In this seminar, Dr. DellaCorte will review the basics of space mechanism tribology and the challenges of providing good lubrication and long-life in the harsh space environment. He will also discuss recent tribological challenges associated with the Solar Alpha Rotary Joint (SARJ) bearings and life support hardware that must operate under severe conditions that are literally out of this world. Each tribology challenge is unique and their solutions often result in new technologies that benefit the tribology community everywhere, even back on Earth

Circulating Tumor Cells: From Theory to Nanotechnology-Based Detection.

PubMed

Ming, Yue; Li, Yuanyuan; Xing, Haiyan; Luo, Minghe; Li, Ziwei; Chen, Jianhong; Mo, Jingxin; Shi, Sanjun

2017-01-01

Cancer stem cells with stem-cell properties are regarded as tumor initiating cells. Sharing stem-cell properties, circulating tumor cells (CTCs) are responsible for the development of metastasis, which significant affects CTC analysis in clinical practice. Due to their extremely low occurrence in blood, however, it is challenging to enumerate and analyze CTCs. Nanotechnology is able to address the problems of insufficient capture efficiency and low purity of CTCs owing to the unique structural and functional properties of nanomaterials, showing strong promise for CTC isolation and detection. In this review, we discuss the role of stem-like CTCs in metastases, provide insight into recent progress in CTC isolation and detection approaches using various nanoplatforms, and highlight the role of nanotechnology in the advancement of CTC research.

Transparent and stretchable high-performance supercapacitors based on wrinkled graphene electrodes.

PubMed

Chen, Tao; Xue, Yuhua; Roy, Ajit K; Dai, Liming

2014-01-28

Transparent and/or stretchable energy storage devices have attracted intense attention due to their unique optical and/or mechanical properties as well as their intrinsic energy storage function. However, it remains a great challenge to integrate transparent and stretchable properties into an energy storage device because the currently developed electrodes are either transparent or stretchable, but not both. Herein, we report a simple method to fabricate wrinkled graphene with high stretchability and transparency. The resultant wrinkled graphene sheets were used as both current collector and electrode materials to develop transparent and stretchable supercapacitors, which showed a high transparency (57% at 550 nm) and can be stretched up to 40% strain without obvious performance change over hundreds of stretching cycles.

VHF NEMS-CMOS piezoresistive resonators for advanced sensing applications

NASA Astrophysics Data System (ADS)

Arcamone, Julien; Dupré, Cécilia; Arndt, Grégory; Colinet, Eric; Hentz, Sébastien; Ollier, Eric; Duraffourg, Laurent

2014-10-01

This work reports on top-down nanoelectromechanical resonators, which are among the smallest resonators listed in the literature. To overcome the fact that their electromechanical transduction is intrinsically very challenging due to their very high frequency (100 MHz) and ultimate size (each resonator is a 1.2 μm long, 100 nm wide, 20 nm thick silicon beam with 100 nm long and 30 nm wide piezoresistive lateral nanowire gauges), they have been monolithically integrated with an advanced fully depleted SOI CMOS technology. By advantageously combining the unique benefits of nanomechanics and nanoelectronics, this hybrid NEMS-CMOS device paves the way for novel breakthrough applications, such as NEMS-based mass spectrometry or hybrid NEMS/CMOS logic, which cannot be fully implemented without this association.

Experience of Implementing ISO 15189 Accreditation at a University Laboratory

PubMed Central

2015-01-01

The present article summarizes the authors’ experience with the implementation of a quality management system based on ISO 17025 and ISO 15189 standards at university laboratories. The accreditation of the analytical procedures at the Universidad Mariano Gálvez represented a challenge due to the unique nature of an educational institution and the difference in nature to the standards implemented. Sample handling and care of the patient were combined to achieve an integrated management system. We explain the development of the management system, the obstacles and benefits of the system and concluding that it is possible to design a management system based on ISO 15189 for the university lab that allowed delivering results assuring technical competence to patient care and welfare. PMID:27683499

2D nanomaterials assembled from sequence-defined molecules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mu, Peng; Zhou, Guangwen; Chen, Chun-Long

Two dimensional (2D) nanomaterials have attracted broad interest owing to their unique physical and chemical properties with potential applications in electronics, chemistry, biology, medicine and pharmaceutics. Due to the current limitations of traditional 2D nanomaterials (e.g., graphene and graphene oxide) in tuning surface chemistry and compositions, 2D nanomaterials assembled from sequence-defined molecules (e.g., DNAs, proteins, peptides and peptoids) have recently been developed. They represent an emerging class of 2D nanomaterials with attractive physical and chemical properties. In this mini-review, we summarize the recent progress in the synthesis and applications of this type of sequence-defined 2D nanomaterials. The challenges and opportunitiesmore » in this new field are also discussed.« less

Evaluation of Current Planetary Boundary Layer Retrieval Capabilities from Space

NASA Technical Reports Server (NTRS)

Santanello, Joseph A., Jr.; Schaefer, Alexander J.; Blaisdell, John; Yorks, John

2016-01-01

The PBL over land remains a significant gap in our water and energy cycle understanding from space. This work combines unique NASA satellite and model products to demonstrate the ability of current sensors (advanced IR sounding and lidar) to retrieve PBL properties and in turn their potential to be used globally to evaluate and improve weather and climate prediction models. While incremental progress has been made in recent AIRS retrieval versions, insufficient vertical resolution remains in terms of detecting PBL properties. Lidar shows promise in terms of detecting vertical gradients (and PBLh) in the lower troposphere, but daytime conditions over land remain a challenge due to noise, and their coverage is limited to approximately 2 weeks or longer return times.

Clinical characteristics of Staphylococcus epidermidis: a systematic review

PubMed Central

Namvar, Amirmorteza Ebrahimzadeh; Bastarahang, Sara; Abbasi, Niloufar; Ghehi, Ghazaleh Sheikhi; Farhadbakhtiarian, Sara; Arezi, Parastoo; Hosseini, Mahsa; Baravati, Sholeh Zaeemi; Jokar, Zahra; Chermahin, Sara Ganji

2014-01-01

Staphylococci are known as clustering Gram-positive cocci, nonmotile, non-spore forming facultatively anaerobic that classified in two main groups, coagulase-positive and coagulase-negative. Staphylococcus epidermidis with the highest percentage has the prominent role among coagulase-negative Staphylococci that is the most important reason of clinical infections. Due to various virulence factors and unique features, this microorganism is respected as a common cause of nosocomial infections. Because of potential ability in biofilm formation and colonization in different surfaces, also using of medical implant devices in immunocompromised and hospitalized patients the related infections have been increased. In recent decades the clinical importance and the emergence of methicillin-resistant Staphylococcus epidermidis strains have created many challenges in the treatment process. PMID:25285267

Gold-Catalyzed Enantio- and Diastereoselective Syntheses of Left Fragments of Azadirachtin/Meliacarpin-Type Limonoids.

PubMed

Shi, Hang; Tan, Ceheng; Zhang, Weibin; Zhang, Zichun; Long, Rong; Gong, Jianxian; Luo, Tuoping; Yang, Zhen

2016-02-05

Meliacarpin-type limonoids are an important class of organic insecticides. Their syntheses are challenging due to their chemical complexity. Here, we report the highly enantio- and diastereoselective synthesis of the left fragments of azadirachtin I and 1-cinnamoylmelianolone, being two important family members of meliacarpin-type limonoids, via pairwise palladium- and gold-catalyzed cascade reactions. Gold-catalyzed reactions of 1,7-diynes were performed as model studies, and the efficient construction of tetracyclic late-stage intermediates was achieved on the basis of this key transformation. Our unique route gave both of the left fragments in 23 steps from the commercially available chiral starting material (-)-carvone. This study significantly advances research on the synthesis of the meliacarpin-type limonoids.

Distributed computation: the new wave of synthetic biology devices.

PubMed

Macía, Javier; Posas, Francesc; Solé, Ricard V

2012-06-01

Synthetic biology (SB) offers a unique opportunity for designing complex molecular circuits able to perform predefined functions. But the goal of achieving a flexible toolbox of reusable molecular components has been shown to be limited due to circuit unpredictability, incompatible parts or random fluctuations. Many of these problems arise from the challenges posed by engineering the molecular circuitry: multiple wires are usually difficult to implement reliably within one cell and the resulting systems cannot be reused in other modules. These problems are solved by means of a nonstandard approach to single cell devices, using cell consortia and allowing the output signal to be distributed among different cell types, which can be combined in multiple, reusable and scalable ways. Copyright © 2012 Elsevier Ltd. All rights reserved.

Graphene-like 2D nanomaterial-based biointerfaces for biosensing applications.

PubMed

Zhu, Chengzhou; Du, Dan; Lin, Yuehe

2017-03-15

Due to their unique structures and multifunctionalities, two-dimensional (2D) nanomaterials have aroused increasing interest in the construction of the novel biointerfaces for biosensing applications. Efforts in constructing novel biointerfaces led to exploit the more versatile and tunable graphene-like 2D nanomaterials (e.g. graphitic carbon nitride, boron nitride, transition metal dichalcogenides, and transition metal oxides) with various structural and compositional characteristics. This review highlights recent efforts in the design of graphene-like 2D nanomaterials and their derived biointerfaces and exploitation of their research on fluorescent sensors and a series of electrochemical sensors, including amperometric, electrochemiluminescence, photoelectrochemical and field-effect transistor sensors. Finally, we discuss some critical challenges and future perspectives in this field. Copyright © 2016. Published by Elsevier B.V.

Designing for Reliability and Robustness in International Space Station Exercise Countermeasures Systems

NASA Technical Reports Server (NTRS)

Moore, Cherice; Svetlik, Randall; Williams, Antony

2017-01-01

As spaceflight durations have increased over the last four decades, the effects of microgravity on the human body have become far better understood, as have the exercise countermeasures. Through use of a combination of aerobic and resistive exercise devices, today's astronauts and cosmonauts are able to partially counter the losses in muscle strength, aerobic fitness, and bone strength that otherwise might occur during their missions on the International Space Station (ISS). Since 2000, the ISS has employed a variety of exercise equipment used as countermeasures to these risks. Providing reliable and available exercise systems has presented significant challenges due to the unique environment. In solving these, lessons have been learned that can inform development of future systems.

CHILDREN'S HEALTH AND THE ENVIRONMENT: PUBLIC HEALTH ISSUES AND CHALLENGES FOR RISK ASSESSMENT

EPA Science Inventory

Infants and children are not little adults. They are uniquely vulnerable to environmental toxicants. To protect infants and children against toxicants, the National Research Council in 1993 called for development of an approach to risk assessment that considers children's unique...

Strategies for Increasing Academic Achievement in Higher Education

ERIC Educational Resources Information Center

Ensign, Julene; Woods, Amelia Mays

2014-01-01

Higher education today faces unique challenges. Decreasing student engagement, increasing diversity, and limited resources all contribute to the issues being faced by students, educators, and administrators alike. The unique characteristics and expectations that students bring to their professional programs require new methods of addressing…

Children's Health and the Environment: Public Health Issues and Challenges for Risk Assessment

EPA Science Inventory

Infants and children are not little adults. They are uniquely vulnerable to environmental toxicants. To protect infants and children against toxicants, the National Research Council in 1993 called for development of an approach to risk assessment that considers children's unique...

Regulatory Considerations in the Design and Manufacturing of Implantable 3D‐Printed Medical Devices

PubMed Central

Morrison, Robert J.; Kashlan, Khaled N.; Flanangan, Colleen L.; Wright, Jeanne K.; Green, Glenn E.; Hollister, Scott J.

2015-01-01

Abstract Three‐dimensional (3D) printing, or additive manufacturing, technology has rapidly penetrated the medical device industry over the past several years, and innovative groups have harnessed it to create devices with unique composition, structure, and customizability. These distinctive capabilities afforded by 3D printing have introduced new regulatory challenges. The customizability of 3D‐printed devices introduces new complexities when drafting a design control model for FDA consideration of market approval. The customizability and unique build processes of 3D‐printed medical devices pose unique challenges in meeting regulatory standards related to the manufacturing quality assurance. Consistent material powder properties and optimal printing parameters such as build orientation and laser power must be addressed and communicated to the FDA to ensure a quality build. Postprinting considerations unique to 3D‐printed devices, such as cleaning, finishing and sterilization are also discussed. In this manuscript we illustrate how such regulatory hurdles can be navigated by discussing our experience with our group's 3D‐printed bioresorbable implantable device. PMID:26243449

Challenges Facing Healthwatch, a New Consumer Champion in England.

PubMed

Carter, Pam; Martin, Graham

2016-01-21

This article engages with debates about the conceptualisation and practical challenges of patient and public involvement (PPI) in health and social care services. Policy in this area in England has shifted numerous times but increasingly a consumerist discourse seems to override more democratic ideas concerning the relationship between citizens and public services. Recent policy change in England has seen the creation of new consumer champion bodies in the form of local Healthwatch. The article describes these new organisational structures for PPI and shows how those who seek to influence planning and delivery of services or comment or complain about aspects of their care face considerable complexity. This is due, in part, to the ambiguous remit set out for newly instigated Healthwatch organisations by government. Drawing on governance theory, we show that it can also be understood as a function of an increasingly polycentric governance arena. Challenges that flow from this include problems of specifying jurisdictional responsibility, accountability, and legitimacy. We review Healthwatch progress to date, then we set out four challenges facing local Healthwatch organisations before discussing the implications of these for patients and the public. The first challenge relates to non-coterminous boundaries and jurisdictional integrity. Secondly, establishing the unique features of Healthwatch is problematic in the crowded PPI arena. The third challenge arises from limited resources as well as the fact that resources flow to Healthwatch from the local authorities that Healthwatch are expected to hold to account. The fourth challenge we identify is how local Healthwatch organisations negotiate the complexity of being a partner to statutory and other organisations, while at the same time being expected to champion local people's views. © 2016 by Kerman University of Medical Sciences.

Isotope labeling for studying RNA by solid-state NMR spectroscopy.

PubMed

Marchanka, Alexander; Kreutz, Christoph; Carlomagno, Teresa

2018-04-12

Nucleic acids play key roles in most biological processes, either in isolation or in complex with proteins. Often they are difficult targets for structural studies, due to their dynamic behavior and high molecular weight. Solid-state nuclear magnetic resonance spectroscopy (ssNMR) provides a unique opportunity to study large biomolecules in a non-crystalline state at atomic resolution. Application of ssNMR to RNA, however, is still at an early stage of development and presents considerable challenges due to broad resonances and poor dispersion. Isotope labeling, either as nucleotide-specific, atom-specific or segmental labeling, can resolve resonance overlaps and reduce the line width, thus allowing ssNMR studies of RNA domains as part of large biomolecules or complexes. In this review we discuss the methods for RNA production and purification as well as numerous approaches for isotope labeling of RNA. Furthermore, we give a few examples that emphasize the instrumental role of isotope labeling and ssNMR for studying RNA as part of large ribonucleoprotein complexes.

Carbon dot/polyvinylpyrrolidone hybrid nanofibers with efficient solid-state photoluminescence constructed using an electrospinning technique

NASA Astrophysics Data System (ADS)

Zhai, Yue; Bai, Xue; Cui, Haining; Zhu, Jinyang; Liu, Wei; Zhang, Tianxiang; Dong, Biao; Pan, Gencai; Xu, Lin; Zhang, Shuang; Song, Hongwei

2018-01-01

Carbon dots (CDs) are the promising candidates for application in optoelectronic and biological areas due to their excellent photostability, unique photoluminescence, good biocompatibility, low toxicity and chemical inertness. However, the self-quenching of photoluminescence as they are dried into the solid state dramatically limits their further application. Therefore, realizing efficient photoluminescence and large-scale production of CDs in the solid state is an urgent challenge. Herein, solid-state hybrid nanofibers based on CDs and polyvinylpyrrolidone (PVP) are constructed through an electrospinning process. The resulting solid-state hybrid PVP/CD nanofibers present much enhanced photoluminescence performance compared to the corresponding pristine colloidal CDs due to the decrease in non-radiative recombination of electron-holes. Owing to the suppressed self-quenching of CDs, the photoluminescence quantum yield is considerably improved from 42.9% of pristine CDs to 83.5% of nanofibers under the excitation wavelength of 360 nm. This has great application potential in optical or optoelectronic devices.

Integrating a redox-coupled dye-sensitized photoelectrode into a lithium-oxygen battery for photoassisted charging.

PubMed

Yu, Mingzhe; Ren, Xiaodi; Ma, Lu; Wu, Yiying

2014-10-03

With a high theoretical specific energy, the non-aqueous rechargeable lithium-oxygen battery is a promising next-generation energy storage technique. However, the large charging overpotential remains a challenge due to the difficulty in electrochemically oxidizing the insulating lithium peroxide. Recently, a redox shuttle has been introduced into the electrolyte to chemically oxidize lithium peroxide. Here, we report the use of a triiodide/iodide redox shuttle to couple a built-in dye-sensitized titanium dioxide photoelectrode with the oxygen electrode for the photoassisted charging of a lithium-oxygen battery. On charging under illumination, triiodide ions are generated on the photoelectrode, and subsequently oxidize lithium peroxide. Due to the contribution of the photovoltage, the charging overpotential is greatly reduced. The use of a redox shuttle to couple a photoelectrode and an oxygen electrode offers a unique strategy to address the overpotential issue of non-aqueous lithium-oxygen batteries and also a distinct approach for integrating solar cells and batteries.

Halophiles, coming stars for industrial biotechnology.

PubMed

Yin, Jin; Chen, Jin-Chun; Wu, Qiong; Chen, Guo-Qiang

2015-11-15

Industrial biotechnology aims to produce chemicals, materials and biofuels to ease the challenges of shortage on petroleum. However, due to the disadvantages of bioprocesses including energy consuming sterilization, high fresh water consumption, discontinuous fermentation to avoid microbial contamination, highly expensive stainless steel fermentation facilities and competing substrates for human consumption, industrial biotechnology is less competitive compared with chemical processes. Recently, halophiles have shown promises to overcome these shortcomings. Due to their unique halophilic properties, some halophiles are able to grow in high pH and high NaCl containing medium under higher temperature, allowing fermentation processes to run contamination free under unsterile conditions and continuous way. At the same time, genetic manipulation methods have been developed for halophiles. So far, halophiles have been used to produce bioplastics polyhydroxyalkanoates (PHA), ectoines, enzymes, and bio-surfactants. Increasing effects have been made to develop halophiles into a low cost platform for bioprocessing with advantages of low energy, less fresh water consumption, low fixed capital investment, and continuous production. Copyright © 2014 Elsevier Inc. All rights reserved.

Assessing downstream flood impacts due to a potential GLOF from Imja Lake in Nepal

NASA Astrophysics Data System (ADS)

Somos-Valenzuela, M. A.; McKinney, D. C.; Byers, A. C.; Rounce, D. R.; Portocarrero, C.; Lamsal, D.

2014-11-01

Glacial-dominated areas pose unique challenges to downstream communities in adapting to recent and continuing global climate change, including increased threats of glacial lake outburst floods (GLOFs) that can increase risk due to flooding of downstream communities and cause substantial impacts on regional social, environmental and economic systems. The Imja glacial lake in Nepal, with potential to generate a GLOF, was studied using a two-dimensional debris flow inundation model in order to evaluate the effectiveness of proposed measures to reduce possible flooding impacts to downstream communities by lowering the lake level. The results indicate that only minor flood impact reduction is achieved in the downstream community of Dingboche with modest (~3 m) lake lowering. Lowering the lake by 10 m shows a significant reduction in inundated area. However, lowering the lake by 20 m almost eliminates all flood impact at Dingboche. Further downstream at Phakding, the impact of the GLOF is significant and similar reductions in inundation are likely as a result of lake lowering.

Designing Mission Operations for the Gravity Recovery and Interior Laboratory Mission

NASA Technical Reports Server (NTRS)

Havens, Glen G.; Beerer, Joseph G.

2012-01-01

NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission, to understand the internal structure and thermal evolution of the Moon, offered unique challenges to mission operations. From launch through end of mission, the twin GRAIL orbiters had to be operated in parallel. The journey to the Moon and into the low science orbit involved numerous maneuvers, planned on tight timelines, to ultimately place the orbiters into the required formation-flying configuration necessary. The baseline GRAIL mission is short, only 9 months in duration, but progressed quickly through seven very unique mission phases. Compressed into this short mission timeline, operations activities and maneuvers for both orbiters had to be planned and coordinated carefully. To prepare for these challenges, development of the GRAIL Mission Operations System began in 2008. Based on high heritage multi-mission operations developed by NASA's Jet Propulsion Laboratory and Lockheed Martin, the GRAIL mission operations system was adapted to meet the unique challenges posed by the GRAIL mission design. This paper describes GRAIL's system engineering development process for defining GRAIL's operations scenarios and generating requirements, tracing the evolution from operations concept through final design, implementation, and validation.

The Challenge of Separating Effects of Simultaneous Education Projects on Student Achievement

ERIC Educational Resources Information Center

Ma, Xin; Ma, Lingling

2009-01-01

When multiple education projects operate in an overlapping or rear-ended manner, it is always a challenge to separate unique project effects on schooling outcomes. Our analysis represents a first attempt to address this challenge. A three-level hierarchical linear model (HLM) was presented as a general analytical framework to separate program…

Proton Exchange Membrane (PEM) Fuel Cells for Space Applications

NASA Technical Reports Server (NTRS)

Bradley, Karla

2004-01-01

This presentation will provide a summary of the PEM fuel cell development at the National Aeronautics and Space Administration, Johnson Space Center (NASA, JSC) in support of future space applications. Fuel cells have been used for space power generation due to their high energy storage density for multi-day missions. The Shuttle currently utilizes the alkaline fuel cell technology, which has highly safe and reliable performance. However, the alkaline technology has a limited life due to the corrosion inherent to the alkaline technology. PEM fuel cells are under development by industry for transportation, residential and commercial stationary power applications. NASA is trying to incorporate some of this stack technology development in the PEM fuel cells for space. NASA has some unique design and performance parameters which make developing a PEM fuel cell system more challenging. Space fuel cell applications utilize oxygen, rather than air, which yields better performance but increases the hazard level. To reduce the quantity of reactants that need to be flown in space, NASA also utilizes water separation and reactant recirculation. Due to the hazards of utilizing active components for recirculation and water separation, NASA is trying to develop passive recirculation and water separation methods. However, the ability to develop recirculation components and water separators that are gravity-independent and successfully operate over the full range of power levels is one of the greatest challenges to developing a safe and reliable PEM fuel cell system. PEM stack, accessory component, and system tests that have been performed for space power applications will be discussed.

Structural and Functional Characterization of a Hole-Hole Homodimer Variant in a "Knob-Into-Hole" Bispecific Antibody.

PubMed

Zhang, Hui-Min; Li, Charlene; Lei, Ming; Lundin, Victor; Lee, Ho Young; Ninonuevo, Milady; Lin, Kevin; Han, Guanghui; Sandoval, Wendy; Lei, Dongsheng; Ren, Gang; Zhang, Jennifer; Liu, Hongbin

2017-12-19

Bispecific antibodies have great potential to be the next-generation biotherapeutics due to their ability to simultaneously recognize two different targets. Compared to conventional monoclonal antibodies, knob-into-hole bispecific antibodies face unique challenges in production and characterization due to the increase in variant possibilities, such as homodimerization in covalent and noncovalent forms. In this study, a storage- and pH-sensitive hydrophobic interaction chromatography (HIC) profile change was observed for the hole-hole homodimer, and the multiple HIC peaks were explored and shown to be conformational isomers. We combined traditional analytical methods with hydrogen/deuterium exchange mass spectrometry (HDX MS), native mass spectrometry, and negative-staining electron microscopy to comprehensively characterize the hole-hole homodimer. HDX MS revealed conformational changes at the resolution of a few amino acids overlapping the C H 2-C H 3 domain interface. Conformational heterogeneity was also assessed by HDX MS isotopic distribution. The hole-hole homodimer was demonstrated to adopt a more homogeneous conformational distribution during storage. This conformational change is likely caused by a lack of C H 3 domain dimerization (due to the three "hole" point mutations), resulting in a unique storage- and pH-dependent conformational destabilization and refolding of the hole-hole homodimer Fc. Compared with the hole-hole homodimer under different storage conditions, the bispecific heterodimer, guided by the knob-into-hole assembly, proved to be a stable conformation with homogeneous distribution, confirming its high quality as a desired therapeutic. Functional studies by antigen binding and neonatal Fc receptor (FcRn) binding correlated very well with the structural characterization. Comprehensive interpretation of the results has provided a better understanding of both the homodimer variant and the bispecific molecule.

Robust Production, Crystallization, Structure Determination, and Analysis of [Fe-S] Proteins: Uncovering Control of Electron Shuttling and Gating in the Respiratory Metabolism of Molybdopterin Guanine Dinucleotide Enzymes.

PubMed

Tsai, Chi-Lin; Tainer, John A

2018-01-01

[Fe-S] clusters are essential cofactors in all domains of life. They play many biological roles due to their unique abilities for electron transfer and conformational control. Yet, producing and analyzing Fe-S proteins can be difficult and even misleading if not done anaerobically. Due to unique redox properties of [Fe-S] clusters and their oxygen sensitivity, they pose multiple challenges and can lose enzymatic activity or cause their component proteins to be structurally disordered due to [Fe-S] cluster oxidation and loss in air. Here we highlight tested protocols and strategies enabling efficient and stable [Fe-S] protein production, purification, crystallization, X-ray diffraction data collection, and structure determination. From multiple high-resolution anaerobic crystal structures, we furthermore analyze exemplary data defining [Fe-S] clusters, substrate entry, and product exit for the functional oxidation states of type II molybdo-bis(molybdopterin guanine dinucleotide) (Mo-bisMGD) enzymes. Notably, these enzymes perform electron shuttling between quinone pools and specific substrates to catalyze respiratory metabolism. The identified structure-activity relationships for this enzyme class have broad implications germane to perchlorate environments on Earth and Mars extending to an alternative mechanism underlying metabolic origins for the evolution of the oxygen atmosphere. Integrated structural analyses of type II Mo-bisMGD enzymes unveil novel distinctive shared molecular mechanisms for dynamic control of substrate entry and product release gated by hydrophobic residues. Collective findings support a prototypic model for type II Mo-bisMGD enzymes including insights for a fundamental molecular mechanistic understanding of selectivity and regulation by a conformationally gated channel with general implications for [Fe-S] cluster respiratory enzymes. © 2018 Elsevier Inc. All rights reserved.

Challenges and Opportunities in Reactive Processing and Applications of Advanced Ceramic Materials

NASA Technical Reports Server (NTRS)

Singh, Mrityunjay

2003-01-01

Recently, there has been a great deal of interest in the research, development, and commercialization of innovative synthesis and processing technologies for advanced ceramics and composite materials. Reactive processing approaches have been actively considered due to their robustness, flexibility, and affordability. A wide variety of silicon carbide-based advanced ceramics and composites are currently being fabricated using the processing approaches involving reactive infiltration of liquid and gaseous species into engineered fibrous or microporous carbon performs. The microporous carbon performs have been fabricated using the temperature induced phase separation and pyrolysis of two phase organic (resin-pore former) mixtures and fiber reinforcement of carbon and ceramic particulate bodies. In addition, pyrolyzed native plant cellulose tissues also provide unique carbon templates for manufacturing of non-oxide and oxide ceramics. In spite of great interest in this technology due to their affordability and robustness, there is a lack of scientific basis for process understanding and many technical challenges still remain. The influence of perform properties and other parameters on the resulting microstructure and properties of final material is not well understood. In this presentation, mechanism of silicon-carbon reaction in various systems and the effect of perform microstructure on the mechanical properties of advanced silicon carbide based materials will be discussed. Various examples of applications of reactively processed advanced silicon carbide ceramics and composite materials will be presented.

Pisgah Lava Cave Communication Test: Science Case Study for the Networked Constellations Initiative

NASA Technical Reports Server (NTRS)

Belov, K.; Ellison, D.; Fraeman, A.

2017-01-01

As part of the science case study for the Networked Constellations initiative, a team of JPL scientists explore the possibility of a mission to study the lava caves on Mars. Natural caves on Mars and the Moon present a unique opportunity to learn about the planetary geology and to provide a shelter for human explorers. Due to power and communication challenges, a network of assets has significant advantages over a single asset sent inside a cave. However, communication between the assets and the data downlink present significant difficulties due to the presence of rough walls, boulders, and other obstacles with unknown dielectric constant inside a typical cave, disturbing the propagation of the radio waves. A detailed study is needed to establish the limitations of the current communication technologies and to develop requirements for the new communication technology applicable to the cave environment. On May 4 of 2017, Konstantin Belov, Doug Ellison, and Abby Fraeman visited a lava cave in Pisgah, CA. The purpose of the visit was to build a 3D map of the cave, which could be used to create a model of radio wave propagation, and to conduct a series of communication tests using off-the-shelf equipment to verify the in-cave communication challenges. This experiment should be considered as a simple 'proof of concept' and is the subject of this report.

Toward a dose reduction strategy using model-based reconstruction with limited-angle tomosynthesis

NASA Astrophysics Data System (ADS)

Haneda, Eri; Tkaczyk, J. E.; Palma, Giovanni; Iordache, Rǎzvan; Zelakiewicz, Scott; Muller, Serge; De Man, Bruno

2014-03-01

Model-based iterative reconstruction (MBIR) is an emerging technique for several imaging modalities and appli- cations including medical CT, security CT, PET, and microscopy. Its success derives from an ability to preserve image resolution and perceived diagnostic quality under impressively reduced signal level. MBIR typically uses a cost optimization framework that models system geometry, photon statistics, and prior knowledge of the recon- structed volume. The challenge of tomosynthetic geometries is that the inverse problem becomes more ill-posed due to the limited angles, meaning the volumetric image solution is not uniquely determined by the incom- pletely sampled projection data. Furthermore, low signal level conditions introduce additional challenges due to noise. A fundamental strength of MBIR for limited-views and limited-angle is that it provides a framework for constraining the solution consistent with prior knowledge of expected image characteristics. In this study, we analyze through simulation the capability of MBIR with respect to prior modeling components for limited-views, limited-angle digital breast tomosynthesis (DBT) under low dose conditions. A comparison to ground truth phantoms shows that MBIR with regularization achieves a higher level of fidelity and lower level of blurring and streaking artifacts compared to other state of the art iterative reconstructions, especially for high contrast objects. The benefit of contrast preservation along with less artifacts may lead to detectability improvement of microcalcification for more accurate cancer diagnosis.

Development challenges of secondary and small airports in California [research brief].

DOT National Transportation Integrated Search

2012-06-01

This report investigates the challenges facing secondary and small airports in California. Low-cost carriers (LCC) have slowly risen to become the dominant air service providers in the state. Their dominance and their unique business model have signi...

International Students at Community Colleges: Challenges and Opportunities for This Unique Segment of U.S. Higher Education

ERIC Educational Resources Information Center

Jennings, Ross

2017-01-01

In unprecedented numbers, American community colleges are seeking to boost their recruitment and retention of international students. This chapter uncovers the challenges and opportunities based on successful experiences in community college efforts.

Dental care in children with developmental disabilities: attention deficit disorder, intellectual disabilities, and autism.

PubMed

Charles, Jane M

2010-01-01

The Federal government reports that 13% of Americans between birth and 18 years of old meet the definition of a child with special health care needs. These children and young adults present unique challenges for both pediatric and general dentists to provide access to the oral health care system--establishing a treatment plan for those with unique medical, behavioral and dental needs and maintaining oral health over the lifetime. The purpose of this article was to describe the characteristics of 3 common developmental disabilities and the challenges these issues present to the oral health care practitioner.

Meeting the Needs of Students with Coexisting Visual Impairments and Learning Disabilities

ERIC Educational Resources Information Center

Jones, Beth A.; Hensley-Maloney, Lauren

2015-01-01

The coexistence of visual impairments and learning disabilities presents unique challenges. It is imperative that teachers be apprised of the characteristics of this population as well as instructional strategies targeted at meeting their unique needs. The authors highlight typical patterns of performance and provide suggestions for effective…

Problems and Prospects of SWAT Model Application on an Arid/Semi-arid Watershed in Arizona

EPA Science Inventory

Hydrological characteristics in the semi-arid southwest create unique challenges to watershed modelers. Streamflow in these regions is largely dependent on seasonal, short term, and high intensity rainfall events. The objectives of this study are: 1) to analyze the unique hydrolo...

Novice Career Changers Weather the Classroom Weather

ERIC Educational Resources Information Center

Gifford, James; Snyder, Mary Grace; Cuddapah, Jennifer Locraft

2013-01-01

A close look at one professional's career change into teaching illustrates unique challenges and qualities, showing in stark relief what makes the induction smoother and the experience more successful. This article presents the story of a novice career changer teacher that illustrates their unique problems and dispositions, as well as…

Is Self-Assessment in Religious Education Unique?

ERIC Educational Resources Information Center

Brooks, Val; Fancourt, Nigel

2012-01-01

This paper addresses the question: is self-assessment in religious education unique? It first presents an overview of some challenges for assessment from subject differences, and then reviews the generic literature on self-assessment. It builds on earlier empirical research on self-assessment in religious education, carried out in an English state…

Problems and Prospects of Swat Model Application on an Arid/Semi-Arid Watershed in Arizona

EPA Science Inventory

Hydrological characteristics in the semi-arid southwest create unique challenges to watershed modellers. Streamflow in these regions is largely dependent on seasonal, short term, and high intensity rainfall events. The objectives of this study are: 1) to analyze the unique hydrol...

An Overview of the Thermal Challenges of Designing Microgravity Furnaces

NASA Technical Reports Server (NTRS)

Westra, Douglas G.

2001-01-01

Marshall Space Flight Center is involved in a wide variety of microgravity projects that require furnaces, with hot zone temperatures ranging from 300 C to 2300 C, requirements for gradient processing and rapid quench, and both semi-conductor and metal materials. On these types of projects, the thermal engineer is a key player in the design process. Microgravity furnaces present unique challenges to the thermal designer. One challenge is designing a sample containment assembly that achieves dual containment, yet allows a high radial heat flux. Another challenge is providing a high axial gradient but a very low radial gradient. These furnaces also present unique challenges to the thermal analyst. First, there are several orders of magnitude difference in the size of the thermal 'conductors' between various parts of the model. A second challenge is providing high fidelity in the sample model, and connecting the sample with the rest of the furnace model, yet maintaining some sanity in the number of total nodes in the model. The purpose of this paper is to present an overview of the challenges involved in designing and analyzing microgravity furnaces and how some of these challenges have been overcome. The thermal analysis tools presently used to analyze microgravity furnaces and will be listed. Challenges for the future and a description of future analysis tools will be given.

On the Development, Characterization, and Use of Protein Fluorescence and Infrared Spectroscopic Probes

NASA Astrophysics Data System (ADS)

Hilaire, Mary Rose

Proteins possess unique physical and chemical properties that allow them to carry out a wide variety of biological activities and functions. While it is generally understood that a protein's function is dictated by its structure and dynamics, arriving at a molecule-level understanding of the underlying structure-dynamics-function relationship still poses a challenging task in many cases. This is due, at least in part, to the fact that we lack the ability to take snapshots along the reaction coordinate of proteins with sufficient temporal and structural resolution. Therefore, to improve one's ability to acquire site-specific structural and/or environmental information of proteins via either infrared (IR) or fluorescence spectroscopy, the main focus of this thesis is to develop and characterize amino acid-based spectroscopic probes as well as to use such probes to study important biological questions. Specifically, we show that (1) p-cyanophenylalanine and selenomethionine constitute an efficient fluorophore-quencher pair, useful for characterizing protein conformational changes that occur on a short distance; (2) 4-cyanotryptophan is a novel blue fluorescent amino acid, applicable for biological imaging due to its unique photophysical properties; (3) the dielectric constant inside the hydrophobic interior of staphylococcal nuclease is about 10-15, significantly larger than previously assumed; and (4) a single mutation in a short segment of the protein transthyretin (i.e., 110-115) induces formation of amyloid fibrils consisting of both beta- and alpha-sheets, where the latter is a proposed structure in proteins, but has never been observed previously.

Computational Approaches for Revealing the Structure of Membrane Transporters: Case Study on Bilitranslocase.

PubMed

Venko, Katja; Roy Choudhury, A; Novič, Marjana

2017-01-01

The structural and functional details of transmembrane proteins are vastly underexplored, mostly due to experimental difficulties regarding their solubility and stability. Currently, the majority of transmembrane protein structures are still unknown and this present a huge experimental and computational challenge. Nowadays, thanks to X-ray crystallography or NMR spectroscopy over 3000 structures of membrane proteins have been solved, among them only a few hundred unique ones. Due to the vast biological and pharmaceutical interest in the elucidation of the structure and the functional mechanisms of transmembrane proteins, several computational methods have been developed to overcome the experimental gap. If combined with experimental data the computational information enables rapid, low cost and successful predictions of the molecular structure of unsolved proteins. The reliability of the predictions depends on the availability and accuracy of experimental data associated with structural information. In this review, the following methods are proposed for in silico structure elucidation: sequence-dependent predictions of transmembrane regions, predictions of transmembrane helix-helix interactions, helix arrangements in membrane models, and testing their stability with molecular dynamics simulations. We also demonstrate the usage of the computational methods listed above by proposing a model for the molecular structure of the transmembrane protein bilitranslocase. Bilitranslocase is bilirubin membrane transporter, which shares similar tissue distribution and functional properties with some of the members of the Organic Anion Transporter family and is the only member classified in the Bilirubin Transporter Family. Regarding its unique properties, bilitranslocase is a potentially interesting drug target.

Synthesis of carbon nanotubes over 3D cubical Co-KIT-6 and nickel decorated graphene by Hummer's method, its application as counter electrode in dye sensitive solar cell

NASA Astrophysics Data System (ADS)

Subramanian, Sunu; Pandurangan, Arumugam

2016-04-01

The challenges on carbon nanotubes and graphene are still the subject of many research works due to its unique properties. There are three main methods to synthesis carbon nanotubes in which chemical vapor deposition (CVD) method can use for large scale production. The principle of CVD is the decomposition of various hydrocarbons over transition metal supported catalyst. KIT-6 molecular sieve was used as a support to prepare cobalt catalyst for CVD method using metal impregnation method to produce cobalt loadings of 2, 4 and 6 wt%. The catalysts were characterized by XRD, FTIR &TEM. Carbon nanotubes (CNTs) synthesized on Co-KIT-6 was also characterized by XRD, TGA, SEM & Raman spectra. Graphene was synthesized by Hummers method, which is the most common method for preparing graphene oxide. Graphene oxide was prepared by oxidation of graphite using some oxidizing agents like sulphuric acid, sodium nitrate and potassium permanganate. This graphene oxide is further treated with hydrazine solution to convert it into chemically converted graphene and also decorated with nickel metal and characterized. Hummer's method is important for large scale production of graphene. Both Graphene and carbon nanotubes are used in different fields due to its unique properties. Both Graphene and carbon nanotubes are fabricated in counter electrode of Dye sensitized solar cells (DSSC). By cyclic voltammetry study, it confirms that both materials are good and efficient to replace platinum in the DSSC.

Gender Dysphoria in the Military.

PubMed

Ford, Shannon; Schnitzlein, Carla

2017-11-07

With the announcement that members of the military who identify as transgender are allowed to serve openly, the need for Department of Defense behavioral health providers to be comfortable in the assessment, diagnosis, and treatment of this population becomes quickly evident. This population has been seeking care in the community and standards have been developed to help guide decision-making, but a comparable document does not exist for the military population. Previously published papers were written in anticipation of the policy allowing for open service. The civilian sector has treatment guidelines and evidence supporting the same for reference. There is no similar document for the military population, likely due to the recent change and ongoing development. This paper attempts to provide an overview of the recent Department of Defense policy and walks the reader through key considerations when providing care to a transgender member of the military as it relates to those who are currently serving in the military through the use of a case example. The military transgender population faces some unique challenges due to the need to balance readiness and deployability with medically necessary health care. Also complicating patient care is that policy development is ongoing-as of this publication, the decision has not yet been made regarding how people who identify as transgender will access into the military nor is there final approval regarding coverage for surgical procedures. Unique circumstances of this population are brought up to generate more discussion and encourage further evaluation and refinement of the process.

Synthetic biology of cyanobacteria: unique challenges and opportunities

PubMed Central

Berla, Bertram M.; Saha, Rajib; Immethun, Cheryl M.; Maranas, Costas D.; Moon, Tae Seok; Pakrasi, Himadri B.

2013-01-01

Photosynthetic organisms, and especially cyanobacteria, hold great promise as sources of renewably-produced fuels, bulk and specialty chemicals, and nutritional products. Synthetic biology tools can help unlock cyanobacteria's potential for these functions, but unfortunately tool development for these organisms has lagged behind that for S. cerevisiae and E. coli. While these organisms may in many cases be more difficult to work with as “chassis” strains for synthetic biology than certain heterotrophs, the unique advantages of autotrophs in biotechnology applications as well as the scientific importance of improved understanding of photosynthesis warrant the development of these systems into something akin to a “green E. coli.” In this review, we highlight unique challenges and opportunities for development of synthetic biology approaches in cyanobacteria. We review classical and recently developed methods for constructing targeted mutants in various cyanobacterial strains, and offer perspective on what genetic tools might most greatly expand the ability to engineer new functions in such strains. Similarly, we review what genetic parts are most needed for the development of cyanobacterial synthetic biology. Finally, we highlight recent methods to construct genome-scale models of cyanobacterial metabolism and to use those models to measure properties of autotrophic metabolism. Throughout this paper, we discuss some of the unique challenges of a diurnal, autotrophic lifestyle along with how the development of synthetic biology and biotechnology in cyanobacteria must fit within those constraints. PMID:24009604

Managing large energy and mineral resources (EMR) projects in challenging environments

NASA Astrophysics Data System (ADS)

Chanmeka, Arpamart

The viability of energy mineral resources (EMR) construction projects is contingent upon the state of the world economic climate. Oil sands projects in Alberta, Canada exemplify large EMR projects that are highly sensitive to fluctuations in the world market. Alberta EMR projects are constrained by high fixed production costs and are also widely recognized as one of the most challenging construction projects to successfully deliver due to impacts from extreme weather conditions, remote locations and issues with labor availability amongst others. As indicated in many studies, these hardships strain the industry's ability to execute work efficiently, resulting in declining productivity and mounting cost and schedule overruns. Therefore, to enhance the competitiveness of Alberta EMR projects, project teams are targeting effective management strategies to enhance project performance and productivity by countering the uniquely challenging environment in Alberta. The main purpose of this research is to develop industry wide benchmarking tailored to the specific constraints and challenges of Alberta. Results support quantitative assessments and identify the root causes of project performance and ineffective field productivity problems in the heavy industry sector capital projects. Customized metrics produced from the data collected through a web-based survey instrument were used to quantitatively assess project performance in the following dimensions: cost, schedule, change, rework, safety, engineering and construction productivity and construction practices. The system enables the industry to measure project performance more accurately, get meaningful comparisons, while establishing credible norms specific to Alberta projects. Data analysis to identify the root cause of performance problems was conducted. The analysis of Alberta projects substantiated lessons of previous studies to create an improved awareness of the abilities of Alberta-based companies to manage their unique projects. This investigation also compared Alberta-based projects with U.S. projects to point out the differences in project process and management strategies under different environments. The relative impact of factors affecting construction productivity were identified and validated by the input from industry experts. The findings help improve the work processes used by companies developing projects in Alberta.

The VSEPR Challenge: A Student's Perspective

ERIC Educational Resources Information Center

Jennings, Ashley S.

2010-01-01

To solve the challenge of learning VSEPR molecules in three dimensions, a high school student leverages her passion for 3D computer animation to develop a creative solution. This article outlines the process and story behind the creation of her unique video. (Contains 1 figure.)

Tailoring Modified Moore Method Techniques to Liberal Arts Mathematics Courses

ERIC Educational Resources Information Center

Hitchman, Theron J.; Shaw, Douglas

2015-01-01

Inquiry-based learning (IBL) techniques can be used in mathematics courses for non-majors, such as courses required for liberal arts majors to fulfill graduation requirements. Unique challenges are discussed, followed by adaptations of IBL techniques to overcome those challenges.

STEM Intervention Programs: Funding Practices and Challenges

ERIC Educational Resources Information Center

Rincon, Blanca E.; George-Jackson, Casey E.

2016-01-01

This study examines the funding practices and challenges of diversity initiatives found in the science, technology, engineering, and mathematics (STEM) fields. Interviews with 55 intervention program administrators, representing 48 unique STEM intervention programs, were conducted at nine large research-intensive universities. The interviews,…

Mississippi communities for healthy living: implementing a nutrition intervention effectiveness study in a rural health disparate region

USDA-ARS?s Scientific Manuscript database

Intervention research in rural, health disparate communities presents unique challenges for study design, implementation, and evaluation. Challenges include: 1) culturally appropriate intervention components; 2) participant recruitment and retention; 3) treatment cross-contamination; 4) intervention...

Conventional Wisdom versus Actual Outcomes: Challenges in the Conduct of an Ebola Vaccine Trial in Liberia during the International Public Health Emergency.

PubMed

Larson, Gregg S; Baseler, Beth R; Hoover, Marie L; Pierson, Jerome F; Tegli, Jemee K; Johnson, Melvin P; Kieh, Mark W S; McNay, Laura A; Njoh, Wissedi Sio

2017-07-01

Clinical trials are challenging endeavors. Planning and implementing an investigational vaccine trial in Liberia, in the midst of an Ebola virus disease (EVD) epidemic that World Health Organization classified a public health emergency of international concern, presented extraordinary challenges. Normally, years of preparation and a litany of tasks lay the groundwork for a successful, randomized, blinded, placebo-controlled trial focused on safety and efficacy. Difficult research settings, unpredictable events, and other unique circumstances can add complexity. The setting in Liberia was especially problematic due to an infrastructure still badly damaged following a lengthy civil war and a very fragile health-care system that was further devastated by the EVD outbreak. The Partnership for Research on Vaccines in Liberia I EVD vaccine trial was planned and implemented in less than 3 months by a Liberian and U.S. research partnership, and its Phase II substudy was fully enrolled 3 months later. Contrasting conventional wisdom with trial outcomes offers an opportunity to compare early assumptions, barriers encountered, and adaptive strategies used, with end results. Understanding what was learned can inform future trial responses when disease outbreaks, especially in resource-poor locations with minimal infrastructure, pose a significant threat to public health.

Conventional Wisdom versus Actual Outcomes: Challenges in the Conduct of an Ebola Vaccine Trial in Liberia during the International Public Health Emergency

PubMed Central

Larson, Gregg S.; Baseler, Beth R.; Hoover, Marie L.; Pierson, Jerome F.; Tegli, Jemee K.; Johnson, Melvin P.; Kieh, Mark W. S.; McNay, Laura A.; Njoh, Wissedi Sio

2017-01-01

Abstract. Clinical trials are challenging endeavors. Planning and implementing an investigational vaccine trial in Liberia, in the midst of an Ebola virus disease (EVD) epidemic that World Health Organization classified a public health emergency of international concern, presented extraordinary challenges. Normally, years of preparation and a litany of tasks lay the groundwork for a successful, randomized, blinded, placebo-controlled trial focused on safety and efficacy. Difficult research settings, unpredictable events, and other unique circumstances can add complexity. The setting in Liberia was especially problematic due to an infrastructure still badly damaged following a lengthy civil war and a very fragile health-care system that was further devastated by the EVD outbreak. The Partnership for Research on Vaccines in Liberia I EVD vaccine trial was planned and implemented in less than 3 months by a Liberian and U.S. research partnership, and its Phase II substudy was fully enrolled 3 months later. Contrasting conventional wisdom with trial outcomes offers an opportunity to compare early assumptions, barriers encountered, and adaptive strategies used, with end results. Understanding what was learned can inform future trial responses when disease outbreaks, especially in resource-poor locations with minimal infrastructure, pose a significant threat to public health. PMID:28719299

UNICEF, syphilis and the state: negotiating female citizenship in the post-Second World War world.

PubMed

Morris, Jennifer

2010-01-01

Few charitable organizations have achieved the status of global recognition enjoyed by UNICEF, the United Nations Children's Fund, which embodies the international effort to provide for needy children the world over. Created because of its synchronicity with the United Nations' stated purpose—to maintain peace in the world—UNICEF launched its operations in 1946. Its founding, early operations and eventual restructuring reveal a great deal about concurrent political and economic events, but also provide keen insight into international ideas about who qualified for full citizenship in the post-war world. The consequences of UNICEF's policies, procedures and practices posed challenges to notions of citizenship for both women and children. It challenged citizenship not by questioning sex-specific gender roles, but by judiciously adhering to the United Nations' promise to create equality for men and women alike. UNICEF found itself in the unique position to be able to globalize definitions of what constituted full citizenship in any nation, due to its rapid expansion throughout the world. Through its programs, especially those related to health care, it not only challenged these roles in the West, but began over several decades to complicate the definition of citizenship as it became a forceful presence in Asia and Africa throughout the 1970s.

Addressing China's grand challenge of achieving food security while ensuring environmental sustainability.

PubMed

Lu, Yonglong; Jenkins, Alan; Ferrier, Robert C; Bailey, Mark; Gordon, Iain J; Song, Shuai; Huang, Jikun; Jia, Shaofeng; Zhang, Fusuo; Liu, Xuejun; Feng, Zhaozhong; Zhang, Zhibin

2015-02-01

China's increasingly urbanized and wealthy population is driving a growing and changing demand for food, which might not be met without significant increase in agricultural productivity and sustainable use of natural resources. Given the past relationship between lack of access to affordable food and political instability, food security has to be given a high priority on national political agendas in the context of globalization. The drive for increased food production has had a significant impact on the environment, and the deterioration in ecosystem quality due to historic and current levels of pollution will potentially compromise the food production system in China. We discuss the grand challenges of not only producing more food but also producing it sustainably and without environmental degradation. In addressing these challenges, food production should be considered as part of an environmental system (soil, air, water, and biodiversity) and not independent from it. It is imperative that new ways of meeting the demand for food are developed while safeguarding the natural resources upon which food production is based. We present a holistic approach to both science and policy to ensure future food security while embracing the ambition of achieving environmental sustainability in China. It is a unique opportunity for China to be a role model as a new global player, especially for other emerging economies.

Haptic control of a pneumatic muscle actuator to provide resistance for simulated isokinetic exercise; part II: control development and testing.

PubMed

Hall, Kara L; Phillips, Chandler A; Reynolds, David B; Mohler, Stanley R; Rogers, Dana B; Neidhard-Doll, Amy T

2015-01-01

Pneumatic muscle actuators (PMAs) have a high power to weight ratio and possess unique characteristics which make them ideal actuators for applications involving human interaction. PMAs are difficult to control due to nonlinear dynamics, presenting challenges in system implementation. Despite these challenges, PMAs have great potential as a source of resistance for strength training and rehabilitation. The objective of this work was to control a PMA for use in isokinetic exercise, potentially benefiting anyone in need of optimal strength training through a joint's range of motion. The controller, based on an inverse three-element phenomenological model and adaptive nonlinear control, allows the system to operate as a type of haptic device. A human quadriceps dynamic simulator was developed (as described in Part I of this work) so that control effectiveness and accommodation could be tested prior to human implementation. Tracking error results indicate that the control system is effective at producing PMA displacement and resistance necessary for a scaled, simulated neuromuscular actuator to maintain low-velocity isokinetic movement during simulated concentric and eccentric knee extension.

SVAS3: Strain Vector Aided Sensorization of Soft Structures.

PubMed

Culha, Utku; Nurzaman, Surya G; Clemens, Frank; Iida, Fumiya

2014-07-17

Soft material structures exhibit high deformability and conformability which can be useful for many engineering applications such as robots adapting to unstructured and dynamic environments. However, the fact that they have almost infinite degrees of freedom challenges conventional sensory systems and sensorization approaches due to the difficulties in adapting to soft structure deformations. In this paper, we address this challenge by proposing a novel method which designs flexible sensor morphologies to sense soft material deformations by using a functional material called conductive thermoplastic elastomer (CTPE). This model-based design method, called Strain Vector Aided Sensorization of Soft Structures (SVAS3), provides a simulation platform which analyzes soft body deformations and automatically finds suitable locations for CTPE-based strain gauge sensors to gather strain information which best characterizes the deformation. Our chosen sensor material CTPE exhibits a set of unique behaviors in terms of strain length electrical conductivity, elasticity, and shape adaptability, allowing us to flexibly design sensor morphology that can best capture strain distributions in a given soft structure. We evaluate the performance of our approach by both simulated and real-world experiments and discuss the potential and limitations.

Preparedness in Long-Term Care: A Novel Approach to Address Gaps in Evacuation Tracking.

PubMed

Prot, Emilie Y; Clements, Bruce

2017-02-01

With an aging population, the number of elderly individuals residing in long-term care (LTC) facilities will continue to grow and pose unique challenges to disaster preparedness and response. With this rapidly growing vulnerable population, it becomes imperative to identify enhanced and novel preparedness strategies and measures. LTC residents not only have complicated medical needs, including the timing of dispensing multiple medications, but frequently have cognitive and mobility deficits as well. In nearly every major disaster, elderly populations have suffered disproportionate morbidity and mortality. This is often due to elderly evacuees getting overlooked in the chaos of an initial response. Instituting measures to rapidly recognize this population in a crowd during an evacuation will reduce their risk. This commentary reviews the LTC facility evacuation challenges of the 2013 explosion of the West Fertilizer Company plant in West, Texas, and offers a novel solution of mandating the wearing of pink vests by all nursing home residents in case of an evacuation. The pink vests quickly alert disaster rescue and response workers of LTC residents with special needs. (Disaster Med Public Health Preparedness. 2017;11:28-30).

Next-generation multiple myeloma treatment: a pharmacoeconomic perspective

PubMed Central

Harousseau, Jean Luc

2016-01-01

Advances in the diagnosis and treatment of multiple myeloma have come at a rapid pace, especially with several new drugs entering the market in the last few years. However, access to and affordability of new treatments poses a major challenge, both in the United States and around the world. High costs of life-saving drugs are detrimental to both the personal finances of the individual patient, as well as society which must bear the increasing costs in terms of increased health insurance premiums, taxes, or both. The challenges are not unique to myeloma, but are commonly encountered in several other cancers as well. But to some extent these pharmacoeconomic concerns are amplified in myeloma due to the need for multidrug regimens that combine 2 or more expensive new drugs, continuous therapy, and the prolonged disease course in most patients. We examine current myeloma therapy from a pharmacoeconomic perspective, and discuss the costs involved. We outline the underlying reasons why cancer drugs are so expensive, the measures that are required to lower cost, and propose potential ways in which costs can be reduced while still delivering high-quality care. PMID:27742709

Innovative Robot Archetypes for In-Space Construction and Maintenance

NASA Technical Reports Server (NTRS)

Rehnmark, Fredrik; Ambrose, Robert O.; Kennedy, Brett; Diftler, Myron; Mehling Joshua; Brigwater, Lyndon; Radford, Nicolaus; Goza, S. Michael; Culbert, Christopher

2005-01-01

The space environment presents unique challenges and opportunities in the assembly, inspection and maintenance of orbital and transit spaceflight systems. While conventional Extra-Vehicular Activity (EVA) technology, out of necessity, addresses each of the challenges, relatively few of the opportunities have been exploited due to crew safety and reliability considerations. Extra-Vehicular Robotics (EVR) is one of the least-explored design spaces but offers many exciting innovations transcending the crane-like Space Shuttle and International Space Station Remote Manipulator System (RMS) robots used for berthing, coarse positioning and stabilization. Microgravity environments can support new robotic archetypes with locomotion and manipulation capabilities analogous to undersea creatures. Such diversification could enable the next generation of space science platforms and vehicles that are too large and fragile to launch and deploy as self-contained payloads. Sinuous manipulators for minimally invasive inspection and repair in confined spaces, soft-stepping climbers with expansive leg reach envelopes and free-flying nanosatellite cameras can access EVA worksites generally not accessible to humans in spacesuits. These and other novel robotic archetypes are presented along with functionality concepts

NRF1 Is an ER Membrane Sensor that Is Central to Cholesterol Homeostasis.

PubMed

Widenmaier, Scott B; Snyder, Nicole A; Nguyen, Truc B; Arduini, Alessandro; Lee, Grace Y; Arruda, Ana Paula; Saksi, Jani; Bartelt, Alexander; Hotamisligil, Gökhan S

2017-11-16

Cholesterol is a critical nutrient requiring tight constraint in the endoplasmic reticulum (ER) due to its uniquely challenging biophysical properties. While the mechanisms by which the ER defends against cholesterol insufficiency are well described, it remains unclear how the ER senses and effectively defends against cholesterol excess. Here, we identify the ER-bound transcription factor nuclear factor erythroid 2 related factor-1, Nrf1/Nfe2L1, as a critical mediator of this process. We show that Nrf1 directly binds to and specifically senses cholesterol in the ER through a defined domain and that cholesterol regulates Nrf1 turnover, processing, localization, and activity. In Nrf1 deficiency, in vivo cholesterol challenges induce massive hepatic cholesterol accumulation and damage, which is rescued by replacing Nrf1 exogenously. This Nrf1-mediated mechanism involves the suppression of CD36-driven inflammatory signaling and derepression of liver X receptor activity. These findings reveal Nrf1 as a guardian of cholesterol homeostasis and a core component of adaptive responses to excess cellular cholesterol. Copyright © 2017. Published by Elsevier Inc.

Why decision support systems are important for medical education.

PubMed

Konstantinidis, Stathis Th; Bamidis, Panagiotis D

2016-03-01

During the last decades, the inclusion of digital tools in health education has rapidly lead to a continuously enlarging digital era. All the online interactions between learners and tutors, the description, creation, reuse and sharing of educational digital resources and the interlinkage between them in conjunction with cheap storage technology has led to an enormous amount of educational data. Medical education is a unique type of education due to accuracy of information needed, continuous changing competences required and alternative methods of education used. Nowadays medical education standards provide the ground for organising the educational data and the paradata. Analysis of such education data through education data mining techniques is in its infancy, but decision support systems (DSSs) for medical education need further research. To the best of our knowledge, there is a gap and a clear need for identifying the challenges for DSSs in medical education in the era of medical education standards. Thus, in this Letter the role and the attributes of such a DSS for medical education are delineated and the challenges and vision for future actions are identified.

Development of the Multiple Use Plug Hybrid for Nanosats (MUPHyN) miniature thruster

NASA Astrophysics Data System (ADS)

Eilers, Shannon

The Multiple Use Plug Hybrid for Nanosats (MUPHyN) prototype thruster incorporates solutions to several major challenges that have traditionally limited the deployment of chemical propulsion systems on small spacecraft. The MUPHyN thruster offers several features that are uniquely suited for small satellite applications. These features include 1) a non-explosive ignition system, 2) non-mechanical thrust vectoring using secondary fluid injection on an aerospike nozzle cooled with the oxidizer flow, 3) a non-toxic, chemically-stable combination of liquid and inert solid propellants, 4) a compact form factor enabled by the direct digital manufacture of the inert solid fuel grain. Hybrid rocket motors provide significant safety and reliability advantages over both solid composite and liquid propulsion systems; however, hybrid motors have found only limited use on operational vehicles due to 1) difficulty in modeling the fuel flow rate 2) poor volumetric efficiency and/or form factor 3) significantly lower fuel flow rates than solid rocket motors 4) difficulty in obtaining high combustion efficiencies. The features of the MUPHyN thruster are designed to offset and/or overcome these shortcomings. The MUPHyN motor design represents a convergence of technologies, including hybrid rocket regression rate modeling, aerospike secondary injection thrust vectoring, multiphase injector modeling, non-pyrotechnic ignition, and nitrous oxide regenerative cooling that address the traditional challenges that limit the use of hybrid rocket motors and aerospike nozzles. This synthesis of technologies is unique to the MUPHyN thruster design and no comparable work has been published in the open literature.

Environmental design implications for two deep space SmallSats

NASA Astrophysics Data System (ADS)

Kahn, Peter; Imken, Travis; Elliott, John; Sherwood, Brent; Frick, Andreas; Sheldon, Douglas; Lunine, Jonathan

2017-10-01

The extreme environmental challenges of deep space exploration force unique solutions to small satellite design in order to enable their use as scientifically viable spacecraft. The challenges of implementing small satellites within limited resources can be daunting when faced with radiation effects on delicate electronics that require shielding or unique adaptations for protection, or mass, power and volume limitations due to constraints placed by the carrier spacecraft, or even Planetary Protection compliant design techniques that drive assembly and testing. This paper will explore two concept studies where the environmental constraints and/or planetary protection mitigations drove the design of the Flight System. The paper will describe the key technical drivers on the Sylph mission concept to explore a plume at Europa as a secondary free-flyer as a part of the planned Europa Mission. Sylph is a radiation-hardened smallsat concept that would utilize terrain relative navigation to fly at low altitudes through a plume, if found, and relay the mass spectra data back through the flyby spacecraft during its 24-h mission. The second topic to be discussed will be the mission design constraints of the Near Earth Asteroid (NEA) Scout concept. NEAScout is a 6U cubesat that would utilize an 86 sq. m solar sail as propulsion to execute a flyby with a near-Earth asteroid and help retire Strategic Knowledge Gaps for future human exploration. NEAScout would cruise for 24 months to reach and characterize one Near-Earth asteroid that is representative of Human Exploration targets and telemeter that data directly back to Earth at the end of its roughly 2.5 year mission.

Investigation of pedestrian crashes on two-way two-lane rural roads in Ethiopia.

PubMed

Tulu, Getu Segni; Washington, Simon; Haque, Md Mazharul; King, Mark J

2015-05-01

Understanding pedestrian crash causes and contributing factors in developing countries is critically important as they account for about 55% of all traffic crashes. Not surprisingly, considerable attention in the literature has been paid to road traffic crash prediction models and methodologies in developing countries of late. Despite this interest, there are significant challenges confronting safety managers in developing countries. For example, in spite of the prominence of pedestrian crashes occurring on two-way two-lane rural roads, it has proven difficult to develop pedestrian crash prediction models due to a lack of both traffic and pedestrian exposure data. This general lack of available data has further hampered identification of pedestrian crash causes and subsequent estimation of pedestrian safety performance functions. The challenges are similar across developing nations, where little is known about the relationship between pedestrian crashes, traffic flow, and road environment variables on rural two-way roads, and where unique predictor variables may be needed to capture the unique crash risk circumstances. This paper describes pedestrian crash safety performance functions for two-way two-lane rural roads in Ethiopia as a function of traffic flow, pedestrian flows, and road geometry characteristics. In particular, random parameter negative binomial model was used to investigate pedestrian crashes. The models and their interpretations make important contributions to road crash analysis and prevention in developing countries. They also assist in the identification of the contributing factors to pedestrian crashes, with the intent to identify potential design and operational improvements. Copyright © 2015. Published by Elsevier Ltd.

Prediction of Indentation Behavior of Superelastic TiNi

NASA Astrophysics Data System (ADS)

Neupane, Rabin; Farhat, Zoheir

2014-09-01

Superelastic TiNi shape memory alloys have been extensively used in various applications. The great interest in TiNi alloys is due to its unique shape memory and superelastic effects, along with its superior wear and dent resistance. Assessment of mechanical properties and dent resistance of superelastic TiNi is commonly performed using indentation techniques. However, the coupling of deformation and reversible martensitic transformation of TiNi under indentation conditions makes the interpretation of results challenging. An attempt is made to enhance current interpretation of indentation data. A load-depth curve is predicted that takes into consideration the reversible martensitic transformation. The predicted curve is in good agreement with experimental results. It is found in this study that the elastic modulus is a function of indentation depth. At shallow depths, the elastic modulus is high due to austenite dominance, while at high depths, the elastic modulus drops as the depth increases due to austenite to martensite transition, i.e., martensite dominance. It is also found that TiNi exhibits superior dent resistance compared to AISI 304 steel. There is two orders of magnitude improvement in dent resistance of TiNi in comparison to AISI 304 steel.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harris, R.A.; Hines, T.L.

Utilization of remote gas resources in developing countries continues to offer challenges and opportunities to producers and contractors. The Aguaytia Gas and Power Project is an example where perseverance and creativity resulted in successful utilization of natural gas resources in the Ucayali Region of Central Peru, a country which previously had no natural gas infrastructure. The resource for the project was first discovered by Mobil in 1961, and remained undeveloped for over thirty years due to lack of infrastructure and markets. Maple Gas won a competitively bid contract to develop the Aguaytia gas reserves in March of 1993. The challengesmore » facing Maple Gas were to develop downstream markets for the gas, execute contracts with Perupetro S.A. and other Peruvian government entities, raise financing for the project, and solicit and execute engineering procurement and construction (EPC) contracts for the execution of the project. The key to development of the downstream markets was the decision to generate electric power and transmit the power over the Andes to the main electrical grid along the coast of Peru. Supplemental revenue could be generated by gas sales to a small regional power plant and extraction of LPG and natural gasoline for consumption in the Peruvian market. Three separate lump sum contracts were awarded to Asea Brown Boveri (ABB) companies for the gas project, power project and transmission project. Each project presented its unique challenges, but the commonalities were the accelerated schedule, high rainfall in a prolonged wet season and severe logistics due to lack of infrastructure in the remote region. This presentation focuses on how the gas plant contractor, ABB Randall, working in harmony with the developer, Maple Gas, tackled the challenges to monetize a remote gas resource.« less

DREAM: Distributed Resources for the Earth System Grid Federation (ESGF) Advanced Management

NASA Astrophysics Data System (ADS)

Williams, D. N.

2015-12-01

The data associated with climate research is often generated, accessed, stored, and analyzed on a mix of unique platforms. The volume, variety, velocity, and veracity of this data creates unique challenges as climate research attempts to move beyond stand-alone platforms to a system that truly integrates dispersed resources. Today, sharing data across multiple facilities is often a challenge due to the large variance in supporting infrastructures. This results in data being accessed and downloaded many times, which requires significant amounts of resources, places a heavy analytic development burden on the end users, and mismanaged resources. Working across U.S. federal agencies, international agencies, and multiple worldwide data centers, and spanning seven international network organizations, the Earth System Grid Federation (ESGF) has begun to solve this problem. Its architecture employs a system of geographically distributed peer nodes that are independently administered yet united by common federation protocols and application programming interfaces. However, significant challenges remain, including workflow provenance, modular and flexible deployment, scalability of a diverse set of computational resources, and more. Expanding on the existing ESGF, the Distributed Resources for the Earth System Grid Federation Advanced Management (DREAM) will ensure that the access, storage, movement, and analysis of the large quantities of data that are processed and produced by diverse science projects can be dynamically distributed with proper resource management. This system will enable data from an infinite number of diverse sources to be organized and accessed from anywhere on any device (including mobile platforms). The approach offers a powerful roadmap for the creation and integration of a unified knowledge base of an entire ecosystem, including its many geophysical, geographical, social, political, agricultural, energy, transportation, and cyber aspects. The resulting aggregation of data combined with analytics services has the potential to generate an informational universe and knowledge system of unprecedented size and value to the scientific community, downstream applications, decision makers, and the public.

Design control considerations for biologic-device combination products.

PubMed

Anderson, Dave; Liu, Roger; Anand Subramony, J; Cammack, Jon

2017-03-01

Combination products are therapeutic and diagnostic medical products that combine drugs, devices, and/or biological products with one another. Historically, biologics development involved identifying efficacious doses administered to patients intravenously or perhaps by a syringe. Until fairly recently, there has been limited focus on developing an accompanying medical device, such as a prefilled syringe or auto-injector, to enable easy and more efficient delivery. For the last several years, and looking forward, where there may be little to distinguish biologics medicines with relatively similar efficacy profiles, the biotechnology market is beginning to differentiate products by patient-focused, biologic-device based combination products. As innovative as biologic-device combination products are, they can pose considerable development, regulatory, and commercialization challenges due to unique physicochemical properties and special clinical considerations (e.g., dosing volumes, frequency, co-medications, etc.) of the biologic medicine. A biologic-device combination product is a marriage between two partners with "cultural differences," so to speak. There are clear differences in the development, review, and commercialization processes of the biologic and the device. When these two cultures come together in a combination product, developers and reviewers must find ways to address the design controls and risk management processes of both the biologic and device, and knit them into a single entity with supporting product approval documentation. Moreover, digital medicine and connected health trends are pushing the boundaries of combination product development and regulations even further. Despite an admirable cooperation between industry and FDA in recent years, unique product configurations and design features have resulted in review challenges. These challenges have prompted agency reviewers to modernize consultation processes, while at the same time, promoting development of innovative, safe and effective combination products. It remains the manufacturer's responsibility to comply with the relevant requirements and regulations, and develop good business practices that clearly describe how these practices comply with FDA's final rule (21 CFR Part 4) and aligns with the company's already established quality system. Copyright © 2017 Elsevier B.V. All rights reserved.

Recognizing Campus Landscapes as Learning Spaces

ERIC Educational Resources Information Center

Scholl, Kathleen G.; Gulwadi, Gowri Betrabet

2015-01-01

American higher education institutions face unique twenty-first century changes and challenges in providing good, holistic learning spaces for the diverse and evolving needs of today's college student. Continued enrollment growth, societal and technological changes, financial challenges, and a need for increased universal and open access create…

Application Security Automation

ERIC Educational Resources Information Center

Malaika, Majid A.

2011-01-01

With today's high demand for online applications and services running on the Internet, software has become a vital component in our lives. With every revolutionary technology comes challenges unique to its characteristics; for online applications, security is one huge concern and challenge. Currently, there are several schemes that address…

Automated vehicle identification tags in San Antonio : lessons learned from the metropolitan model deployment initiative : unique method for collecting arterial travel speed information

DOT National Transportation Integrated Search

2000-10-01

This report demonstrates a unique solution to the challenge of providing accurate, timely estimates of arterial travel times to the motoring public. In particular, it discusses the lessons learned in deploying the Vehicle Tag Project in San Antonio, ...

Myth 17: Gifted and Talented Individuals Do Not Have Unique Social and Emotional Needs

ERIC Educational Resources Information Center

Peterson, Jean Sunde

2009-01-01

Empirical and clinical literatures have challenged the myth that gifted students do not have unique social and emotional concerns. When this myth prevails, pertinent concerns are not recognized and addressed formally or informally, proactively or reactively. Educators, parents, coaches, and even counselors may miss indications of distress. Lack of…

Building Vocabulary of English Learners with Reading Disabilities through Computer-Assisted Morphology Instruction

ERIC Educational Resources Information Center

Lo, Ya-yu; Anderson, Adrienne L.; Bunch-Crump, Kimberly

2017-01-01

Many educators in public schools in the United States experience challenges in meeting the unique needs of the growing population of English learners who must simultaneously attain academic skills while acquiring English language proficiency. Such unique needs intensify for English learners with reading disabilities. Morphological awareness is key…

Examining the Development of Self-Authorship among Student Veterans

ERIC Educational Resources Information Center

Stone, Sharon L. M.

2014-01-01

The literature has shown that student veterans arrive in college with unique characteristics and also face unique challenges (Black et al., 2007; Bonar & Domenici, 2011; Church, 2009; DiRamio & Jarvis, 2011). There is also some evidence that student veterans develop complex ways of making meaning at younger ages than students in the…

Mystic Chords of Memory: Cultivating America's Unique Form of Patriotism.

ERIC Educational Resources Information Center

Berns, Walter

2002-01-01

Describes the history of U.S. patriotism, asserting that anchored though it is to a set of ideas, there are unique challenges to educating patriots. Suggests the importance of telling the nation's stories through civics education. Explains that patriotism is cultivated when students learn about democratic values, people and events shaping the…

Morphology supporting function: attenuation correction for SPECT/CT, PET/CT, and PET/MR imaging

PubMed Central

Lee, Tzu C.; Alessio, Adam M.; Miyaoka, Robert M.; Kinahan, Paul E.

2017-01-01

Both SPECT, and in particular PET, are unique in medical imaging for their high sensitivity and direct link to a physical quantity, i.e. radiotracer concentration. This gives PET and SPECT imaging unique capabilities for accurately monitoring disease activity for the purposes of clinical management or therapy development. However, to achieve a direct quantitative connection between the underlying radiotracer concentration and the reconstructed image values several confounding physical effects have to be estimated, notably photon attenuation and scatter. With the advent of dual-modality SPECT/CT, PET/CT, and PET/MR scanners, the complementary CT or MR image data can enable these corrections, although there are unique challenges for each combination. This review covers the basic physics underlying photon attenuation and scatter and summarizes technical considerations for multimodal imaging with regard to PET and SPECT quantification and methods to address the challenges for each multimodal combination. PMID:26576737

Clay-based polymer nanocomposites: research and commercial development.

PubMed

Zeng, Q H; Yu, A B; Lu, G Q; Paul, D R

2005-10-01

This paper reviews the recent research and development of clay-based polymer nanocomposites. Clay minerals, due to their unique layered structure, rich intercalation chemistry and availability at low cost, are promising nanoparticle reinforcements for polymers to manufacture low-cost, lightweight and high performance nanocomposites. We introduce briefly the structure, properties and surface modification of clay minerals, followed by the processing and characterization techniques of polymer nanocomposites. The enhanced and novel properties of such nanocomposites are then discussed, including mechanical, thermal, barrier, electrical conductivity, biodegradability among others. In addition, their available commercial and potential applications in automotive, packaging, coating and pigment, electrical materials, and in particular biomedical fields are highlighted. Finally, the challenges for the future are discussed in terms of processing, characterization and the mechanisms governing the behaviour of these advanced materials.

Polymer/Carbon-Based Hybrid Aerogels: Preparation, Properties and Applications

PubMed Central

Zuo, Lizeng; Zhang, Youfang; Zhang, Longsheng; Miao, Yue-E; Fan, Wei; Liu, Tianxi

2015-01-01

Aerogels are synthetic porous materials derived from sol-gel materials in which the liquid component has been replaced with gas to leave intact solid nanostructures without pore collapse. Recently, aerogels based on natural or synthetic polymers, called polymer or organic aerogels, have been widely explored due to their porous structures and unique properties, such as high specific surface area, low density, low thermal conductivity and dielectric constant. This paper gives a comprehensive review about the most recent progresses in preparation, structures and properties of polymer and their derived carbon-based aerogels, as well as their potential applications in various fields including energy storage, adsorption, thermal insulation and flame retardancy. To facilitate further research and development, the technical challenges are discussed, and several future research directions are also suggested in this review. PMID:28793602

Robots and therapeutic play: evaluation of a wireless interface device for interaction with a robot playmate.

PubMed

Roberts, Luke; Park, Hae Won; Howard, Ayanna M

2012-01-01

Rehabilitation robots in home environments has the potential to dramatically improve quality of life for individuals who experience disabling circumstances due to injury or chronic health conditions. Unfortunately, although classes of robotic systems for rehabilitation exist, these devices are typically not designed for children. And since over 150 million children in the world live with a disability, this causes a unique challenge for deploying such robotics for this target demographic. To overcome this barrier, we discuss a system that uses a wireless arm glove input device to enable interaction with a robotic playmate during various play scenarios. Results from testing the system with 20 human subjects shows that the system has potential, but certain aspects need to be improved before deployment with children.

Circulating Tumor Cells: From Theory to Nanotechnology-Based Detection

PubMed Central

Ming, Yue; Li, Yuanyuan; Xing, Haiyan; Luo, Minghe; Li, Ziwei; Chen, Jianhong; Mo, Jingxin; Shi, Sanjun

2017-01-01

Cancer stem cells with stem-cell properties are regarded as tumor initiating cells. Sharing stem-cell properties, circulating tumor cells (CTCs) are responsible for the development of metastasis, which significant affects CTC analysis in clinical practice. Due to their extremely low occurrence in blood, however, it is challenging to enumerate and analyze CTCs. Nanotechnology is able to address the problems of insufficient capture efficiency and low purity of CTCs owing to the unique structural and functional properties of nanomaterials, showing strong promise for CTC isolation and detection. In this review, we discuss the role of stem-like CTCs in metastases, provide insight into recent progress in CTC isolation and detection approaches using various nanoplatforms, and highlight the role of nanotechnology in the advancement of CTC research. PMID:28203204

Review of Adaptive Programmable Materials and Their Bioapplications.

PubMed

Fan, Xiaoshan; Chung, Jing Yang; Lim, Yong Xiang; Li, Zibiao; Loh, Xian Jun

2016-12-14

Adaptive programmable materials have attracted increasing attention due to their high functionality, autonomous behavior, encapsulation, and site-specific confinement capabilities in various applications. Compared to conventional materials, adaptive programmable materials possess unique single-material architecture that can maintain, respond, and change their shapes and dimensions when they are subjected to surrounding environment changes, such as alternation in temperature, pH, and ionic strength. In this review, the most-recent advances in the design strategies of adaptive programmable materials are presented with respect to different types of architectural polymers, including stimuli-responsive polymers and shape-memory polymers. The diverse functions of these sophisticated materials and their significance in therapeutic agent delivery systems are also summarized in this review. Finally, the challenges for facile fabrication of these materials and future prospective are also discussed.

Sustaining Health for Wealth: Perspectives for the Post-2015 Agenda

PubMed Central

Armah, Bartholomew K.

2015-01-01

The sustainable development goals (SDGs) offer a unique opportunity for policy-makers to build on the millennium development goals (MDGs) by adopting more sustainable approaches to addressing global development challenges. The delivery of health services is of particular concern. Most African countries are unlikely to achieve the health MDGs, however, significant progress has been made particularly in the area of child and maternal health due in part to significant external support. The weak global recovery, and persistent inequalities in access to healthcare, however, call into question the sustainability of the achievements made. Building on the principles articulated in Binagwaho and Scott, this commentary argues that addressing inequalities and promoting more integrated approaches to health service delivery is vital for consolidating and sustaining the health sector achievements in Africa. PMID:26673177

Superparamagnetic iron oxide nanoparticles: promises for diagnosis and treatment of cancer

PubMed Central

Laurent, Sophie; Mahmoudi, Morteza

2011-01-01

During the last decade, significant scientific research efforts have led to a significant growth in understanding of cancer at the genetic, molecular, and cellular levels providing great opportunities for diagnosis and treatment of cancer diseases. The hopes for fast cancer diagnosis and treatment were significantly increased by the entrance of nanoparticles to the medical sciences. Nanoparticles are attractive due to their unique opportunities together with negligible side effects not only in cancer therapy but also in the treatment of other ailments. Among all types of nanoparticles, surface-engineered superparamagnetic iron oxide nanoparticles (SPIONs) have been attracted a great attention for cancer therapy applications. This review covers the recent advances in the development of SPIONs together with their opportunities and challenges, as theranosis agents, in cancer treatment. PMID:22199999

Japan's advanced medicine.

PubMed

Sho, Ri; Narimatsu, Hiroto; Murakami, Masayasu

2013-10-01

Like health care systems in other developed countries, Japan's health care system faces significant challenges due to aging of the population and economic stagnation. Advanced medicine (Senshin Iryou) is a unique system of medical care in Japan offering highly technology-driven medical care that is not covered by public health insurance. Advanced medicine has recently developed and expanded as part of health care reform. Will it work? To answer this question, we briefly trace the historical development of advanced medicine and describe the characteristics and current state of advanced medical care in Japan. We then offer our opinions on the future of advanced medicine with careful consideration of its pros and cons. We believe that developing advanced medicine is an attempt to bring health care reform in line rather than the goal of health care reform.

Understanding risks and complications in the management of ankle fractures

PubMed Central

Mehta, Saurabh Sagar; Rees, Kishan; Cutler, Lucy; Mangwani, Jitendra

2014-01-01

Ankle fracture (AF) is a common injury with potentially significant morbidity associated with it. The most common age groups affected are young active patients, sustaining high energy trauma and elderly patients with comorbidities. Both these groups pose unique challenges for appropriate management of these injuries. Young patients are at risk of developing posttraumatic osteoarthritis, with a significant impact on quality of life due to pain and impaired function. Elderly patients, especially with poorly controlled diabetes and osteoporosis are at increased risk of wound complications, infection and failure of fixation. In the most severe cases, this can lead to amputation and mortality. Therefore, individualized approach to the management of AF is vital. This article highlights commonly encountered complications and discusses the measures needed to minimize them when dealing with these injuries. PMID:25298549

Nanofabrication of ultra-low reflectivity black silicon surfaces and devices (Presentation Recording)

NASA Astrophysics Data System (ADS)

White, Victor E.; Yee, Karl Y.; Balasubramanian, Kunjithapatham; Echternach, Pierre M.; Muller, Richard E.; Dickie, Matthew R.; Cady, Eric; Ryan, Daniel J.; Eastwood, Michael; van Gorp, Byron; Riggs, A. J. Eldorado; Zimmerman, Niel; Kasdin, N. Jeremy

2015-08-01

Optical devices with features exhibiting ultra low reflectivity on the order of 10-7 specular reflectance in the visible spectrum are required for coronagraph instruments and some spectrometers employed in space research. Nanofabrication technologies have been developed to produce such devices with various shapes and feature dimensions to meet these requirements. Infrared reflection is also suppressed significantly with chosen wafers and processes. Particularly, devices with very high (>0.9) and very low reflectivity (<10-7) on adjacent areas have been fabricated and characterized. Significantly increased surface area due to the long needle like nano structures also provides some unique applications in other technology areas. We present some of the approaches, challenges and achieved results in producing and characterizing such devices currently employed in laboratory testbeds and instruments.

A non-uniformly sampled 4D HCC(CO)NH-TOCSY experiment processed using maximum entropy for rapid protein sidechain assignment

PubMed Central

Mobli, Mehdi; Stern, Alan S.; Bermel, Wolfgang; King, Glenn F.; Hoch, Jeffrey C.

2010-01-01

One of the stiffest challenges in structural studies of proteins using NMR is the assignment of sidechain resonances. Typically, a panel of lengthy 3D experiments are acquired in order to establish connectivities and resolve ambiguities due to overlap. We demonstrate that these experiments can be replaced by a single 4D experiment that is time-efficient, yields excellent resolution, and captures unique carbon-proton connectivity information. The approach is made practical by the use of non-uniform sampling in the three indirect time dimensions and maximum entropy reconstruction of the corresponding 3D frequency spectrum. This 4D method will facilitate automated resonance assignment procedures and it should be particularly beneficial for increasing throughput in NMR-based structural genomics initiatives. PMID:20299257

Synthesis of Helical Carbon Fibers and Related Materials: A Review on the Past and Recent Developments

PubMed Central

Raghubanshi, Himanshu; Dikio, Ezekiel Dixon

2015-01-01

Helical carbon fibers (HCFs) have been widely studied due to their unique helical morphology and superior properties, which make them efficient materials for several potential applications. This review summarizes the past and current advancement on the synthesis of HCFs. The review focuses and discusses synthesis strategies and effect of experimental parameters on the growth of HCFs. The effect of preparation method of catalyst, catalyst nature, catalyst composition, catalyst size, catalyst initial and final shape, reaction temperature, reaction time, carbon source, impurities, and electromagnetic field on the growth of HCFs is reviewed. We also discuss the growth mechanism for HCFs and the synthesis of HCFs related materials. Finally, we conclude with a brief summary and an outlook on the challenges and future prospects of HCFs. PMID:28347045

Influence of IR sensor technology on the military and civil defense

NASA Astrophysics Data System (ADS)

Becker, Latika

2006-02-01

Advances in basic infrared science and developments in pertinent technology applications have led to mature designs being incorporated in civil as well as military area defense systems. Military systems include both tactical and strategic, and civil area defense includes homeland security. Technical challenges arise in applying infrared sensor technology to detect and track targets for space and missile defense. Infrared sensors are valuable due to their passive capability, lower mass and power consumption, and their usefulness in all phases of missile defense engagements. Nanotechnology holds significant promise in the near future by offering unique material and physical properties to infrared components. This technology is rapidly developing. This presentation will review the current IR sensor technology, its applications, and future developments that will have an influence in military and civil defense applications.

Challenges and climate of business environment and resources to support pediatric device development.

PubMed

Iqbal, Corey W; Wall, James; Harrison, Michael R

2015-06-01

The incidence of pediatric disease conditions pales in comparison to adult disease. Consequently, many pediatric disorders are considered orphan diseases. Resources for the development of devices targeting orphan diseases are scarce and this poses a unique challenge to the development of pediatric devices. This article outlines these challenges and offers solutions. Copyright © 2015 Elsevier Inc. All rights reserved.

Anesthetic management during cardiopulmonary bypass: a systematic review.

PubMed

Barry, Aaron E; Chaney, Mark A; London, Martin J

2015-04-01

Cardiopulmonary bypass (CPB) required for cardiac surgery presents unique challenges to the cardiac anesthesiologist responsible for providing the 3 most basic facets of any anesthetic: amnesia, analgesia, and muscle relaxation. Unique pathophysiologic changes during CPB result in pharmacokinetic alterations that impact the serum and tissue concentrations of IV and volatile anesthetics. Similarly, CPB causes pharmacodynamic alterations that impact anesthetic efficacy. The clinical significance of these alterations represents a "moving target" as practice evolves and the technology of CPB circuitry advances. In addition, perfusionists choose, modify, and maintain the CPB circuitry and membrane oxygenator. Thus, their significance may not be fully appreciated by the anesthesiologist. These issues have a profound impact on the anesthetic state of the patient. The delivery and maintenance of anesthesia during CPB present unique challenges. The perfusionist may be directly responsible for the delivery of anesthetic during CPB, a situation unique to the cardiac suite. In addition, monitors of anesthetic depth-assessment of clinical signs, hemodynamic indicators, the bispectral index monitor, end-tidal anesthetic concentration, or twitch monitoring-are often absent, unreliable, or directly impacted by the unique pathophysiology associated with CPB. The magnitude of these challenges is reflected in the higher incidence of intraoperative awareness during cardiac surgery. Further complicating matters are the lack of specific clinical guidelines and varying international policies regarding medical device specifications that add further layers of complexity and introduce practice variability both within institutions and among nations. We performed a systematic survey of the literature to identify where anesthetic practice during CPB is evidence based (or not), identify gaps in the literature to guide future investigations, and explore the implications of evolving surgical practice, perfusion techniques, and national policies that impact amnesia, analgesia, and muscle relaxation during CPB.

Information technology and behavioral medicine: impact on autism treatment & research.

PubMed

Oberleitner, Ron; Laxminarayan, Swamy

2004-01-01

Families, clinicians and researchers involved with varying neurological disorders face amazing challenges to understand, treat, and assist the people they are serving. Autism brings unique challenges and serves as an important model for the application of important concepts in information technology and telemedicine. The rising incidence of autism with limited professional resources has led to more consideration for using information technology and related specialties to link families and professionals, and to implement strategies which implement information technology to improve the outcomes for individuals with autism and their families. These are reviewed in context of the unique health, education, and the research issues facing those dealing with autism.

Technology Challenges for Deep-Throttle Cryogenic Engines for Space Exploration

NASA Technical Reports Server (NTRS)

Brown, Kendall K.; Nelson, Karl W.

2005-01-01

Historically, cryogenic rocket engines have not been used for in-space applications due to their additional complexity, the mission need for high reliability, and the challenges of propellant boil-off. While the mission and vehicle architectures are not yet defined for the lunar and Martian robotic and human exploration objectives, cryogenic rocket engines offer the potential for higher performance and greater architecture/mission flexibility. In-situ cryogenic propellant production could enable a more robust exploration program by significantly reducing the propellant mass delivered to low earth orbit, thus warranting the evaluation of cryogenic rocket engines versus the hypergolic bi-propellant engines used in the Apollo program. A multi-use engine. one which can provide the functionality that separate engines provided in the Apollo mission architecture, is desirable for lunar and Mars exploration missions because it increases overall architecture effectiveness through commonality and modularity. The engine requirement derivation process must address each unique mission application and each unique phase within each mission. The resulting requirements, such as thrust level, performance, packaging, bum duration, number of operations; required impulses for each trajectory phase; operation after extended space or surface exposure; availability for inspection and maintenance; throttle range for planetary descent, ascent, acceleration limits and many more must be addressed. Within engine system studies, the system and component technology, capability, and risks must be evaluated and a balance between the appropriate amount of technology-push and technology-pull must be addressed. This paper will summarize many of the key technology challenges associated with using high-performance cryogenic liquid propellant rocket engine systems and components in the exploration program architectures. The paper is divided into two areas. The first area describes how the mission requirements affect the engine system requirements and create system level technology challenges. An engine system architecture for multiple applications or a family of engines based upon a set of core technologies, design, and fabrication approaches may reduce overall programmatic cost and risk. The engine system discussion will also address the characterization of engine cycle figures of merit, configurations, and design approaches for some in-space vehicle alternatives under consideration. The second area evaluates the component-level technology challenges induced from the system requirements. Component technology issues are discussed addressing injector, thrust chamber, ignition system, turbopump assembly, and valve design for the challenging requirements of high reliability, robustness, fault tolerance, deep throttling, reasonable performance (with respect to weight and specific impulse).

Technology Challenges for Deep-Throttle Cryogenic Engines for Space Exploration

NASA Astrophysics Data System (ADS)

Brown, Kendall K.; Nelson, Karl W.

2005-02-01

Historically, cryogenic rocket engines have not been used for in-space applications due to their additional complexity, the mission need for high reliability, and the challenges of propellant boil-off. While the mission and vehicle architectures are not yet defined for the lunar and Martian robotic and human exploration objectives, cryogenic rocket engines offer the potential for higher performance and greater architecture/mission flexibility. In-situ cryogenic propellant production could enable a more robust exploration program by significantly reducing the propellant mass delivered to low earth orbit, thus warranting the evaluation of cryogenic rocket engines versus the hypergolic bipropellant engines used in the Apollo program. A multi-use engine, one which can provide the functionality that separate engines provided in the Apollo mission architecture, is desirable for lunar and Mars exploration missions because it increases overall architecture effectiveness through commonality and modularity. The engine requirement derivation process must address each unique mission application and each unique phase within each mission. The resulting requirements, such as thrust level, performance, packaging, burn duration, number of operations; required impulses for each trajectory phase; operation after extended space or surface exposure; availability for inspection and maintenance; throttle range for planetary descent, ascent, acceleration limits and many more must be addressed. Within engine system studies, the system and component technology, capability, and risks must be evaluated and a balance between the appropriate amount of technology-push and technology-pull must be addressed. This paper will summarize many of the key technology challenges associated with using high-performance cryogenic liquid propellant rocket engine systems and components in the exploration program architectures. The paper is divided into two areas. The first area describes how the mission requirements affect the engine system requirements and create system level technology challenges. An engine system architecture for multiple applications or a family of engines based upon a set of core technologies, design, and fabrication approaches may reduce overall programmatic cost and risk. The engine system discussion will also address the characterization of engine cycle figures of merit, configurations, and design approaches for some in-space vehicle alternatives under consideration. The second area evaluates the component-level technology challenges induced from the system requirements. Component technology issues are discussed addressing injector, thrust chamber, ignition system, turbopump assembly, and valve design for the challenging requirements of high reliability, robustness, fault tolerance, deep throttling, reasonable performance (with respect to weight and specific impulse).

Adolescence and AAC: Intervention Challenges and Possible Solutions

ERIC Educational Resources Information Center

Smith, Martine M.

2015-01-01

Adolescence is a unique developmental period, spanning the gulf between childhood and adulthood. For adolescents who use augmentative and alternative communication (AAC), the major physical, cognitive, linguistic, social, and emotional changes associated with adolescence may have significant implications for their use of AAC. These challenges are…

How to Survive the First Year of Teaching.

ERIC Educational Resources Information Center

Harris, Judy J.

2003-01-01

Discusses the unique challenges of the first year of teaching. Challenges include over enrollment, long hours, and overload of paperwork. Gives advice on how new teachers can overcome problems by creating alliances within the spiritual community, working with administrators, and taking care of their health. (MZ)

A Story of African American Students as Mathematics Learners

ERIC Educational Resources Information Center

Morton, Crystal Hill

2014-01-01

Educational systems throughout the world serve students from diverse populations. Often students from minority populations (i.e. racial, ethnic, linguistic, cultural, economic) face unique challenges when learning in contexts based on the cultural traditions and learning theories of the majority population. These challenges often leave minority…

Extracellular-Matrix-Based and Arg-Gly-Asp–Modified Photopolymerizing Hydrogels for Cartilage Tissue Engineering

PubMed Central

Kim, Hwan D.; Heo, Jiseung; Hwang, Yongsung; Kwak, Seon-Yeong; Park, Ok Kyu; Kim, Hyunbum; Varghese, Shyni

2015-01-01

Articular cartilage damage is a persistent and increasing problem with the aging population. Strategies to achieve complete repair or functional restoration remain a challenge. Photopolymerizing-based hydrogels have long received an attention in the cartilage tissue engineering, due to their unique bioactivities, flexible method of synthesis, range of constituents, and desirable physical characteristics. In the present study, we have introduced unique bioactivity within the photopolymerizing-based hydrogels by copolymerizing polyethylene glycol (PEG) macromers with methacrylated extracellular matrix (ECM) molecules (hyaluronic acid and chondroitin sulfate [CS]) and integrin binding peptides (RGD peptide). Results indicate that cellular morphology, as observed by the actin cytoskeleton structures, was strongly dependent on the type of ECM component as well as the presence of integrin binding moieties. Further, CS-based hydrogel with integrin binding RGD moieties increased the lubricin (or known as superficial zone protein [SZP]) gene expression of the encapsulated chondrocytes. Additionally, CS-based hydrogel displayed cell-responsive degradation and resulted in increased DNA, GAG, and collagen accumulation compared with other hydrogels. This study demonstrates that integrin-mediated interactions within CS microenvironment provide an optimal hydrogel scaffold for cartilage tissue engineering application. PMID:25266634

From silk to satellite: half a century of ocean colour anomalies in the Northeast Atlantic.

PubMed

Raitsos, Dionysios E; Pradhan, Yaswant; Lavender, Samantha J; Hoteit, Ibrahim; McQuatters-Gollop, Abigail; Reid, Phillip C; Richardson, Anthony J

2014-07-01

Changes in phytoplankton dynamics influence marine biogeochemical cycles, climate processes, and food webs, with substantial social and economic consequences. Large-scale estimation of phytoplankton biomass was possible via ocean colour measurements from two remote sensing satellites - the Coastal Zone Colour Scanner (CZCS, 1979-1986) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS, 1998-2010). Due to the large gap between the two satellite eras and differences in sensor characteristics, comparison of the absolute values retrieved from the two instruments remains challenging. Using a unique in situ ocean colour dataset that spans more than half a century, the two satellite-derived chlorophyll-a (Chl-a) eras are linked to assess concurrent changes in phytoplankton variability and bloom timing over the Northeast Atlantic Ocean and North Sea. Results from this unique re-analysis reflect a clear increasing pattern of Chl-a, a merging of the two seasonal phytoplankton blooms producing a longer growing season and higher seasonal biomass, since the mid-1980s. The broader climate plays a key role in Chl-a variability as the ocean colour anomalies parallel the oscillations of the Northern Hemisphere Temperature (NHT) since 1948. © 2013 John Wiley & Sons Ltd.

Unique Cobalt Sulfide/Reduced Graphene Oxide Composite as an Anode for Sodium-Ion Batteries with Superior Rate Capability and Long Cycling Stability.

PubMed

Peng, Shengjie; Han, Xiaopeng; Li, Linlin; Zhu, Zhiqiang; Cheng, Fangyi; Srinivansan, Madhavi; Adams, Stefan; Ramakrishna, Seeram

2016-03-09

Exploitation of high-performance anode materials is essential but challenging to the development of sodium-ion batteries (SIBs). Among all proposed anode materials for SIBs, sulfides have been proved promising candidates due to their unique chemical and physical properties. In this work, a facile solvothermal method to in situ decorate cobalt sulfide (CoS) nanoplates on reduced graphene oxide (rGO) to build CoS@rGO composite is described. When evaluated as anode for SIBs, an impressive high specific capacity (540 mAh g(-1) at 1 A g(-1) ), excellent rate capability (636 mAh g(-1) at 0.1 A g(-1) and 306 mAh g(-1) at 10 A g(-1)), and extraordinarily cycle stability (420 mAh g(-1) at 1 A g(-1) after 1000 cycles) have been demonstrated by CoS@rGO composite for sodium storage. The synergetic effect between the CoS nanoplates and rGO matrix contributes to the enhanced electrochemical performance of the hybrid composite. The results provide a facile approach to fabricate promising anode materials for high-performance SIBs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Right-Handed Helical Foldamers Consisting of De Novo d -AApeptides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teng, Peng; Ma, Ning; Cerrato, Darrell Cole

New types of foldamer scaffolds are formidably challenging to design and synthesize, yet highly desirable as structural mimics of peptides/proteins with a wide repertoire of functions. In particular, the development of peptidomimetic helical foldamers holds promise for new biomaterials, catalysts, and drug molecules. Unnatural l-sulfono-γ-AApeptides were recently developed and shown to have potential applications in both biomedical and material sciences. However, d-sulfono-γ-AApeptides, the enantiomers of l-sulfono-γ-AApeptides, have never been studied due to the lack of high-resolution three-dimensional structures to guide structure-based design. Herein, we report the first synthesis and X-ray crystal structures of a series of 2:1 l-amino acid/d-sulfono-γ-AApeptide hybridmore » foldamers, and elucidate their folded conformation at the atomic level. Single-crystal X-ray crystallography indicates that this class of oligomers folds into well-defined right-handed helices with unique helical parameters. The helical structures were consistent with data obtained from solution 2D NMR, CD studies, and molecular dynamics simulations. Our findings are expected to inspire the structure-based design of this type of unique folding biopolymers for biomaterials and biomedical applications.« less

Development of a Dynamically Scaled Generic Transport Model Testbed for Flight Research Experiments

NASA Technical Reports Server (NTRS)

Jordan, Thomas; Langford, William; Belcastro, Christine; Foster, John; Shah, Gautam; Howland, Gregory; Kidd, Reggie

2004-01-01

This paper details the design and development of the Airborne Subscale Transport Aircraft Research (AirSTAR) test-bed at NASA Langley Research Center (LaRC). The aircraft is a 5.5% dynamically scaled, remotely piloted, twin-turbine, swept wing, Generic Transport Model (GTM) which will be used to provide an experimental flight test capability for research experiments pertaining to dynamics modeling and control beyond the normal flight envelope. The unique design challenges arising from the dimensional, weight, dynamic (inertial), and actuator scaling requirements necessitated by the research community are described along with the specific telemetry and control issues associated with a remotely piloted subscale research aircraft. Development of the necessary operational infrastructure, including operational and safety procedures, test site identification, and research pilots is also discussed. The GTM is a unique vehicle that provides significant research capacity due to its scaling, data gathering, and control characteristics. By combining data from this testbed with full-scale flight and accident data, wind tunnel data, and simulation results, NASA will advance and validate control upset prevention and recovery technologies for transport aircraft, thereby reducing vehicle loss-of-control accidents resulting from adverse and upset conditions.

Hippocampal maturity promotes memory distinctiveness in childhood and adolescence

PubMed Central

Keresztes, Attila; Bender, Andrew R.; Bodammer, Nils C.; Shing, Yee Lee

2017-01-01

Adaptive learning systems need to meet two complementary and partially conflicting goals: detecting regularities in the world versus remembering specific events. The hippocampus (HC) keeps a fine balance between computations that extract commonalities of incoming information (i.e., pattern completion) and computations that enable encoding of highly similar events into unique representations (i.e., pattern separation). Histological evidence from young rhesus monkeys suggests that HC development is characterized by the differential development of intrahippocampal subfields and associated networks. However, due to challenges in the in vivo investigation of such developmental organization, the ontogenetic timing of HC subfield maturation remains controversial. Delineating its course is important, as it directly influences the fine balance between pattern separation and pattern completion operations and, thus, developmental changes in learning and memory. Here, we relate in vivo, high-resolution structural magnetic resonance imaging data of HC subfields to behavioral memory performance in children aged 6–14 y and in young adults. We identify a multivariate profile of age-related differences in intrahippocampal structures and show that HC maturity as captured by this pattern is associated with age differences in the differential encoding of unique memory representations. PMID:28784801

Bayesian inversion of the global present-day GIA signal uncertainty from RSL data

NASA Astrophysics Data System (ADS)

Caron, Lambert; Ivins, Erik R.; Adhikari, Surendra; Larour, Eric

2017-04-01

Various geophysical signals measured in the process of studying the present-day climate change (such as changes in the Earth gravitational potential, ocean altimery or GPS data) include a secular Glacial Isostatic Adjustment contribution that has to be corrected for. Yet, one of the current major challenges that Glacial Isostatic Adjustment modelling is currently struggling with is to accurately determine the uncertainty of the predicted present-day GIA signal. This is especially true at the global scale, where coupling between ice history and mantle rheology greatly contributes to the non-uniqueness of the solutions. Here we propose to use more than 11000 paleo sea level records to constrain a set of GIA Bayesian inversions and thoroughly explore its parameters space. We include two linearly relaxing models to represent the mantle rheology and couple them with a scalable ice history model in order to better assess the non-uniqueness of the solutions. From the resulting estimates of the Probability Density Function, we then extract maps of uncertainty affecting the present-day vertical land motion and geoid due to GIA at the global scale, and their associated expectation of the signal.

A cellulosic responsive "living" membrane.

PubMed

Qin, Guokui; Panilaitis, Bruce J; Kaplan, Zhongyuan Sun David L

2014-01-16

Bacterial cellulose has been demonstrated to be a remarkably versatile biomaterial and widely used in biomedical applications due to its unique physical properties. Here we reported for the first time a "living membrane" system based on recombinant Escherichia coli bacterial strains entrapped in cellulosic membranes produced by Gluconacetobacter xylinus. Biologically driven detection and identification of a range of target molecules presents unique challenges, and requires that detection methods are developed to be rapid, specific and sensitive. The compatibility of G. xylinus and recombinant E. coli strains was first investigated for co-cultivation, and the relationship between the number of entrapped E. coli and the level of inducible signal achieved was further explored by fluorescent signal observation in confocal microscopy. Finally to amplify the response to inducers for maximum fluorescent signal, a positive-feedback genetic amplifier was designed within recombinant E. coli strain entrapped in the living cellulosic membrane system, allowing for the detection mechanism to be extremely sensitive and resulting in a significant fluorescent signal from a single receptor binding event. The living membrane system proposed here will create devices of greater complexity in function for applications in biological and chemical detection. Copyright © 2013. Published by Elsevier Ltd.

A diagnostic signal selection scheme for planetary gearbox vibration monitoring under non-stationary operational conditions

NASA Astrophysics Data System (ADS)

Feng, Ke; Wang, KeSheng; Zhang, Mian; Ni, Qing; Zuo, Ming J.

2017-03-01

The planetary gearbox, due to its unique mechanical structures, is an important rotating machine for transmission systems. Its engineering applications are often in non-stationary operational conditions, such as helicopters, wind energy systems, etc. The unique physical structures and working conditions make the vibrations measured from planetary gearboxes exhibit a complex time-varying modulation and therefore yield complicated spectral structures. As a result, traditional signal processing methods, such as Fourier analysis, and the selection of characteristic fault frequencies for diagnosis face serious challenges. To overcome this drawback, this paper proposes a signal selection scheme for fault-emphasized diagnostics based upon two order tracking techniques. The basic procedures for the proposed scheme are as follows. (1) Computed order tracking is applied to reveal the order contents and identify the order(s) of interest. (2) Vold-Kalman filter order tracking is used to extract the order(s) of interest—these filtered order(s) constitute the so-called selected vibrations. (3) Time domain statistic indicators are applied to the selected vibrations for faulty information-emphasized diagnostics. The proposed scheme is explained and demonstrated in a signal simulation model and experimental studies and the method proves to be effective for planetary gearbox fault diagnosis.

Fast flux module detection using matroid theory.

PubMed

Reimers, Arne C; Bruggeman, Frank J; Olivier, Brett G; Stougie, Leen

2015-05-01

Flux balance analysis (FBA) is one of the most often applied methods on genome-scale metabolic networks. Although FBA uniquely determines the optimal yield, the pathway that achieves this is usually not unique. The analysis of the optimal-yield flux space has been an open challenge. Flux variability analysis is only capturing some properties of the flux space, while elementary mode analysis is intractable due to the enormous number of elementary modes. However, it has been found by Kelk et al. (2012) that the space of optimal-yield fluxes decomposes into flux modules. These decompositions allow a much easier but still comprehensive analysis of the optimal-yield flux space. Using the mathematical definition of module introduced by Müller and Bockmayr (2013b), we discovered useful connections to matroid theory, through which efficient algorithms enable us to compute the decomposition into modules in a few seconds for genome-scale networks. Using that every module can be represented by one reaction that represents its function, in this article, we also present a method that uses this decomposition to visualize the interplay of modules. We expect the new method to replace flux variability analysis in the pipelines for metabolic networks.

Temporomandibular Joint Regenerative Medicine

PubMed Central

Van Bellinghen, Xavier; Idoux-Gillet, Ysia; Pugliano, Marion; Strub, Marion; Bornert, Fabien; Clauss, Francois; Schwinté, Pascale; Keller, Laetitia; Benkirane-Jessel, Nadia; Lutz, Jean Christophe; Fioretti, Florence

2018-01-01

The temporomandibular joint (TMJ) is an articulation formed between the temporal bone and the mandibular condyle which is commonly affected. These affections are often so painful during fundamental oral activities that patients have lower quality of life. Limitations of therapeutics for severe TMJ diseases have led to increased interest in regenerative strategies combining stem cells, implantable scaffolds and well-targeting bioactive molecules. To succeed in functional and structural regeneration of TMJ is very challenging. Innovative strategies and biomaterials are absolutely crucial because TMJ can be considered as one of the most difficult tissues to regenerate due to its limited healing capacity, its unique histological and structural properties and the necessity for long-term prevention of its ossified or fibrous adhesions. The ideal approach for TMJ regeneration is a unique scaffold functionalized with an osteochondral molecular gradient containing a single stem cell population able to undergo osteogenic and chondrogenic differentiation such as BMSCs, ADSCs or DPSCs. The key for this complex regeneration is the functionalization with active molecules such as IGF-1, TGF-β1 or bFGF. This regeneration can be optimized by nano/micro-assisted functionalization and by spatiotemporal drug delivery systems orchestrating the 3D formation of TMJ tissues. PMID:29393880

Rational Design of Au@Pt Multibranched Nanostructures as Bifunctional Nanozymes.

PubMed

Wu, Jiangjiexing; Qin, Kang; Yuan, Dan; Tan, Jun; Qin, Li; Zhang, Xuejin; Wei, Hui

2018-04-18

One of the current challenges in nanozyme-based nanotechnology is the utilization of multifunctionalities in one material. In this regard, Au@Pt nanoparticles (NPs) with excellent enzyme-mimicking activities due to the Pt shell and unique surface plasmon resonance features from the Au core have attracted enormous research interest. However, the unique surface plasmon resonance features from the Au core have not been widely utilized. The practical problem of the optical-damping nature of Pt hinders the research into the combination of Au@Pt NPs' enzyme-mimicking properties with their surface-enhanced Raman scattering (SERS) activities. Herein, we rationally tuned the Pt amount to achieve Au@Pt NPs with simultaneous plasmonic and enzyme-mimicking activities. The results showed that Au@Pt NPs with 2.5% Pt produced the highest Raman signal in 2 min, which benefited from the remarkably accelerated catalytic oxidation of 3,3',5,5'-tetramethylbenzidine with the decorated Pt and strong electric field retained from the Au core for SERS. This study not only demonstrates the great promise of combining bimetallic nanomaterials' multiple functionalities but also provides rational guidelines to design high-performance nanozymes for potential biomedical applications.

Contemporary issues on the epidemiology and antiretroviral adherence of HIV-infected adolescents in sub-Saharan Africa: a narrative review

PubMed Central

Adejumo, Olurotimi A; Malee, Kathleen M; Ryscavage, Patrick; Hunter, Scott J; Taiwo, Babafemi O

2015-01-01

Introduction Adolescents are a unique and sometimes neglected group in the planning of healthcare services. This is the case in many parts of sub-Saharan Africa, where more than eight out of ten of the world's HIV-infected adolescents live. Although the last decade has seen a reduction in AIDS-related mortality worldwide, largely due to improved access to effective antiretroviral therapy (ART), AIDS remains a significant contributor to adolescent mortality in sub-Saharan Africa. Although inadequate access to ART in parts of the subcontinent may be implicated, research among youth with HIV elsewhere in the world suggests that suboptimal adherence to ART may play a significant role. In this article, we summarize the epidemiology of HIV among sub-Saharan African adolescents and review their adherence to ART, emphasizing the unique challenges and factors associated with adherence behaviour. Methods We conducted a comprehensive search of online databases for articles, relevant abstracts, and conference reports from meetings held between 2010 and 2014. Our search terms included “adherence,” “compliance,” “antiretroviral use” and “antiretroviral adherence,” in combination with “adolescents,” “youth,” “HIV,” “Africa,” “interventions” and the MeSH term “Africa South of the Sahara.” Of 19,537 articles and abstracts identified, 215 met inclusion criteria, and 148 were reviewed. Discussion Adolescents comprise a substantial portion of the population in many sub-Saharan African countries. They are at particular risk of HIV and may experience worse outcomes. Although demonstrated to have unique challenges, there is a dearth of comprehensive health services for adolescents, especially for those with HIV in sub-Saharan Africa. ART adherence is poorer among older adolescents than other age groups, and psychosocial, socio-economic, individual, and treatment-related factors influence adherence behaviour among adolescents in this region. With the exception of a few examples based on affective, cognitive, and behavioural strategies, most adherence interventions have been targeted at adults with HIV. Conclusions Although higher levels of ART adherence have been reported in sub-Saharan Africa than in other well-resourced settings, adolescents in the region may have poorer adherence patterns. There is substantial need for interventions to improve adherence in this unique population. PMID:26385853

Unique phase identification of trimetallic copper iron manganese oxygen carrier using simultaneous differential scanning calorimetry/thermogravimetric analysis during chemical looping combustion reactions with methane

DOE PAGES

Benincosa, William; Siriwardane, Ranjani; Tian, Hanjing; ...

2017-07-05

Chemical looping combustion (CLC) is a promising combustion technology that generates heat and sequestration-ready carbon dioxide that is undiluted by nitrogen from the combustion of carbonaceous fuels with an oxygen carrier, or metal oxide. This process is highly dependent on the reactivity and stability of the oxygen carrier. The development of oxygen carriers remains one of the major barriers for commercialization of CLC. Synthetic oxygen carriers, consisting of multiple metal components, have demonstrated enhanced performance and improved CLC operation compared to single metal oxides. However, identification of the complex mixed metal oxide phases that form after calcination or during CLCmore » reactions has been challenging. Without an understanding of the dominant metal oxide phase, it is difficult to determine reaction parameters and the oxygen carrier reduction pathway, which are necessary for CLC reactor design. This is particularly challenging for complex multi-component oxygen carriers such as copper iron manganese oxide (CuFeMnO 4). This study aims to differentiate the unique phase formation of a highly reactive, complex trimetallic oxygen carrier, CuFeMnO 4, from its single and bimetallic counterparts using thermochemical and reaction data obtained from simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) during temperature programmed reductions (TPR) with methane. DSC/TGA experiments during TPR with methane provides heat flow data and corresponding reaction rate data that can be used to determine reaction routes and mechanisms during methane reduction. Furthermore, non-isothermal TPR data provides the advantage of distinguishing reactions that may not be observable in isothermal analysis. The detailed thermochemical and reaction data, obtained during TPR with methane, distinguished a unique reduction pathway for CuFeMnO 4 that differed from its single and bimetallic counterparts. This is remarkable since X-ray diffraction (XRD) data alone could not be used to distinguish the reactive trimetallic oxide phase due to overlapping peaks from various single and mixed metal oxides. The unique reduction pathway of CuFeMnO 4 was further characterized in this study using in-situ XRD TPR with methane to determine changes in the dominant trimetallic phase that influenced the thermochemical and reaction rate data.« less

Unique phase identification of trimetallic copper iron manganese oxygen carrier using simultaneous differential scanning calorimetry/thermogravimetric analysis during chemical looping combustion reactions with methane

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benincosa, William; Siriwardane, Ranjani; Tian, Hanjing

Chemical looping combustion (CLC) is a promising combustion technology that generates heat and sequestration-ready carbon dioxide that is undiluted by nitrogen from the combustion of carbonaceous fuels with an oxygen carrier, or metal oxide. This process is highly dependent on the reactivity and stability of the oxygen carrier. The development of oxygen carriers remains one of the major barriers for commercialization of CLC. Synthetic oxygen carriers, consisting of multiple metal components, have demonstrated enhanced performance and improved CLC operation compared to single metal oxides. However, identification of the complex mixed metal oxide phases that form after calcination or during CLCmore » reactions has been challenging. Without an understanding of the dominant metal oxide phase, it is difficult to determine reaction parameters and the oxygen carrier reduction pathway, which are necessary for CLC reactor design. This is particularly challenging for complex multi-component oxygen carriers such as copper iron manganese oxide (CuFeMnO 4). This study aims to differentiate the unique phase formation of a highly reactive, complex trimetallic oxygen carrier, CuFeMnO 4, from its single and bimetallic counterparts using thermochemical and reaction data obtained from simultaneous differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) during temperature programmed reductions (TPR) with methane. DSC/TGA experiments during TPR with methane provides heat flow data and corresponding reaction rate data that can be used to determine reaction routes and mechanisms during methane reduction. Furthermore, non-isothermal TPR data provides the advantage of distinguishing reactions that may not be observable in isothermal analysis. The detailed thermochemical and reaction data, obtained during TPR with methane, distinguished a unique reduction pathway for CuFeMnO 4 that differed from its single and bimetallic counterparts. This is remarkable since X-ray diffraction (XRD) data alone could not be used to distinguish the reactive trimetallic oxide phase due to overlapping peaks from various single and mixed metal oxides. The unique reduction pathway of CuFeMnO 4 was further characterized in this study using in-situ XRD TPR with methane to determine changes in the dominant trimetallic phase that influenced the thermochemical and reaction rate data.« less

Video-mosaicking of in vivo reflectance confocal microscopy images for noninvasive examination of skin lesion (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kose, Kivanc; Gou, Mengran; Yelamos, Oriol; Cordova, Miguel A.; Rossi, Anthony; Nehal, Kishwer S.; Camps, Octavia I.; Dy, Jennifer G.; Brooks, Dana H.; Rajadhyaksha, Milind

2017-02-01

In this report we describe a computer vision based pipeline to convert in-vivo reflectance confocal microscopy (RCM) videos collected with a handheld system into large field of view (FOV) mosaics. For many applications such as imaging of hard to access lesions, intraoperative assessment of MOHS margins, or delineation of lesion margins beyond clinical borders, raster scan based mosaicing techniques have clinically significant limitations. In such cases, clinicians often capture RCM videos by freely moving a handheld microscope over the area of interest, but the resulting videos lose large-scale spatial relationships. Videomosaicking is a standard computational imaging technique to register, and stitch together consecutive frames of videos into large FOV high resolution mosaics. However, mosaicing RCM videos collected in-vivo has unique challenges: (i) tissue may deform or warp due to physical contact with the microscope objective lens, (ii) discontinuities or "jumps" between consecutive images and motion blur artifacts may occur, due to manual operation of the microscope, and (iii) optical sectioning and resolution may vary between consecutive images due to scattering and aberrations induced by changes in imaging depth and tissue morphology. We addressed these challenges by adapting or developing new algorithmic methods for videomosaicking, specifically by modeling non-rigid deformations, followed by automatically detecting discontinuities (cut locations) and, finally, applying a data-driven image stitching approach that fully preserves resolution and tissue morphologic detail without imposing arbitrary pre-defined boundaries. We will present example mosaics obtained by clinical imaging of both melanoma and non-melanoma skin cancers. The ability to combine freehand mosaicing for handheld microscopes with preserved cellular resolution will have high impact application in diverse clinical settings, including low-resource healthcare systems.

Comparison of Student and Instructor Perceptions of Social Presence

ERIC Educational Resources Information Center

Mathieson, Kathleen; Leafman, Joan S.

2014-01-01

As enrollment in online courses continues to grow and online education is increasingly recognized as an established instructional mode, the unique challenges posed by this learning environment should be addressed. A primary challenge for virtual educators is developing social presence such that participants feel a sense of human connection with…

Adoption of Internet2 in a Southwestern University: Human Resources Concerns

ERIC Educational Resources Information Center

Mendoza-Diaz, Noemi V.; Dooley, Larry M.; Dooley, Kim E.

2007-01-01

Human Resources are often times challenged by the integration of new technologies (Benson, Johnson, & Kichinke, 2002). Universities pose a unique challenge since they reluctantly adapt to changes (Torraco & Hoover, 2005; Watkins 2005). This is a dissertation study of the human resource concerns about adopting Internet2 in a…

Communication Challenges During Incidents of National Significance: A Lesson From Hurricane Katrina

DTIC Science & Technology

2006-03-15

Belle Chasse 17 Sep Qualcomm cellular tower installed at NAS New Orleans23 The timeline referenced above illustrates the very limited communications...active Army do provide unique assets in their responses to such crises . A significant challenge of interoperability between the DoD assets and first

Classroom Management Challenges in the Dance Class

ERIC Educational Resources Information Center

Clark, Dawn

2007-01-01

Teaching dance can be a challenge because of the unique classroom-management situations that arise from the dynamic nature of the class content. Management is a delicate navigation of advance planning; rule setting; the establishment and implementation of daily protocols, routines, and interventions; and the teacher's own presentation. This…

Contextual Influences on Faculty Diversity Conceptualizations when Working with Trainee Competence Problems

ERIC Educational Resources Information Center

Shen-Miller, David S.; Forrest, Linda; Burt, Michelle

2012-01-01

Trainees with problems of professional competence (TPPC) present trainers with unique challenges. When TPPC situations include diversity issues, the complexity of such challenges increases. Although attention to such intersections is important, little is known about what influences faculty thinking about diversity issues when trainee competence…

Evaluation Options for Family Resource Centers.

ERIC Educational Resources Information Center

Horsch, Karen, Ed.; Weiss, Heather B., Ed.

Family resource centers (FRC) are emerging as a promising program approach to solving urgent social problems. Evaluation plays an important role in learning how these programs work, what their impact is, and whether they should be expanded. However, FRCs pose unique challenges to evaluation. This report considers the challenges to evaluating FRCs,…

Student Parents and Financial Aid. Working Paper

ERIC Educational Resources Information Center

Huelsman, Mark; Engle, Jennifer

2013-01-01

Student parents face many challenges to accessing, persisting, and completing postsecondary education. While some of these challenges are unique to student parents--such as finding quality child care during class and work hours and juggling studying and academic assignments with parenting duties--others are typical of low-income and underserved…

Increasing Participation of Rural and Regional Students in Higher Education

ERIC Educational Resources Information Center

Fleming, Michele J.; Grace, Diana M.

2014-01-01

Regional and rural students in Australia face unique challenges when aspiring to higher education. These challenges reflect systematic disadvantage experienced by rural and regional populations as a whole. In an effort to redress these inequities, and aided by the Australian Government's Higher Education Participation and Partnerships Program…

Improving Information Products for System 2 Decision Support

ERIC Educational Resources Information Center

Gibson, Neal

2010-01-01

The creation, maintenance, and management of Information Product (IP) systems that are used by organizations for complex decisions represent a unique set of challenges. These challenges are compounded when the purpose of such a systems is also for knowledge creation and dissemination. Information quality research to date has focused mainly upon…

The Unique Challenges to the Well-Being of California's Border Kids

ERIC Educational Resources Information Center

Barondess, Heather; Newhouse, Corey

2007-01-01

This report presents community-level indicators about the educational, health, and economic status of children and families living along the California/Mexico border. Providing a balanced view of the communities' strengths and areas for improvement, this report challenges negative stereotypes of the region while calling for substantial…

Effective Strategies for Talking about Climate Change in the Classroom

ERIC Educational Resources Information Center

Busch, K. C.; Osborne, Jonathan

2014-01-01

Teaching about climate science presents some unique challenges. Unlike many other science topics, mitigation and adaptation to climate change will require students to take action. This article outlines five major challenges to communicating about climate change in the classroom, drawing on research in environmental psychology: scepticism,…

Special Educators' Perceptions of State Standards in a Large, Urban School District

ERIC Educational Resources Information Center

Cramer, Elizabeth D.; Gallo, Rosalia F.

2017-01-01

The implementation of Common Core State Standards raises challenges for teachers, particularly those in urban settings and those who work with students with unique learning challenges, particularly students with disabilities. This article provides the results of a study that surveyed special education teachers' perspectives related to the…

A Challenge to Watson

ERIC Educational Resources Information Center

Detterman, Douglas K.

2011-01-01

Watson's Jeopardy victory raises the question of the similarity of artificial intelligence and human intelligence. Those of us who study human intelligence issue a challenge to the artificial intelligence community. We will construct a unique battery of tests for any computer that would provide an actual IQ score for the computer. This is the same…

Bridging Borders: Global Perspectives in Education

ERIC Educational Resources Information Center

Lath, Meenakshi

2009-01-01

The individualization of curriculum is a challenge for the teacher education system in India. Curricula are prescribed by Universities for all the affiliated colleges, and these undergo revision only every few years. The curriculum innovation described in this report is a response to this challenge. The study explores a unique case of the…

Women Superintendents in Illinois: Gender Barriers and Challenges

ERIC Educational Resources Information Center

VanTuyle, Vicki; Watkins, Sandra G.

2009-01-01

Women face unique challenges as superintendents. This study determined barriers women face as superintendents and elicited reasons why these women would consider leaving the superintendent's position. Thirty-nine PreK-12 women superintendents in Illinois participated in a web-based survey in January 2008. Survey items included information…

The Contemporary Student Center: Challenges at Metropolitan Universities

ERIC Educational Resources Information Center

Henry, Wilma J.

2004-01-01

As the student center movement--to upgrade, expand, or acquire a new facility--continues in the new millennium, metropolitan institutions, in particular, are finding that their unique circumstances often challenge their ability to keep pace with their nonmetropolitan counterparts. This research presents the results of a study of the role of…

The Impact of Divorce: A Multivariate Study.

ERIC Educational Resources Information Center

Kolevzon, Michael S.; Gottlieb, Susan J.

1983-01-01

Surveyed 157 divorced parents to assess phases of emotional adjustment following divorce. Findings provided no evidence to suggest that particular dimensions of emotional adjustment represent challenges unique to particular stages of divorce. The intensity and the duration of emotional challenges were affected by a number of intervening variables.…

Classroom Needs of Community College Students with Asperger's Disorder and Autism Spectrum Disorders

ERIC Educational Resources Information Center

Gobbo, Ken; Shmulsky, Solvegi

2012-01-01

Community college students with Asperger's Disorder and Autism Spectrum Disorders can experience significant challenges from the social aspect of classroom learning and college life in comparison to their peers. This article explains unique challenges of postsecondary learners with Asperger's Disorder and Autism Spectrum Disorders. It also…

Parenting and the Process of Migration: Possibilities within South Asian Families

ERIC Educational Resources Information Center

Deepak, Anne C.

2005-01-01

The migration experience creates a unique set of challenges for families, which can result in intergenerational conflict and create the conditions for abuse or neglect. Alternatively, families can cope with these challenges in creative and seemingly contradictory ways, thus strengthening family relationships. This article introduces the process of…

Career Development Practitioners as Advocates for Transgender Individuals: Understanding Gender Transition

ERIC Educational Resources Information Center

Sangganjanavanich, Varunee Faii

2009-01-01

Assisting transgender individuals is a concern for career development practitioners because there is a lack of knowledge on this topic. The complexity of gender reassignment surgery brings challenges and unique needs to this population, throughout gender transition, and requires career development practitioners to understand these challenges and…

A Working Model of a New American University

ERIC Educational Resources Information Center

Crow, Michael M.; Loui, Kimberly

2006-01-01

American universities confront unique challenges as they move into the twenty-first century. These include rapid population growth, demographic and economic changes on both global and regional levels, and the numerous local challenges that face today's communities. Modern universities must engage, and in turn be engaged by, their communities in…

Career Decision-Making and College and Career Access among Recent African Immigrant Students

ERIC Educational Resources Information Center

Wambu, Grace; Hutchison, Brian; Pietrantoni, Zachary

2017-01-01

The number of African immigrant youth in American classrooms is on the rise. School counselors are uniquely positioned to help these students to be college and career ready. Using the Social Cognitive Career Theory framework, this article aims to address the unique career development needs, college and career access challenges faced by African…

Increasing Research Capacity in Ontario Child Welfare Organizations: A Unique University-Child Welfare Agency Partnership

ERIC Educational Resources Information Center

Fallon, Barbara; Trocmé, Nico; Van Wert, Melissa; Budau, Krista; Ballantyne, Mary; Lwin, Kristen

2015-01-01

The objective of this article is to describe the successes and challenges of a unique knowledge mobilization initiative that was funded through the Social Sciences and Humanities Research Council of Canada. This initiative focused on promoting knowledge mobilization by increasing the capacity of child welfare organizations in Ontario to conduct…

Education, Technology, and the Asian-American Community: Forging a Unique Identity in the Face of Unique Challenges

ERIC Educational Resources Information Center

Subramony, Deepak Prem

2007-01-01

In an effort to mitigate our field's historic neglect of issues of cultural diversity, this article seeks to introduce Asian-Americans--a fascinating, important, and under-researched group of learners and technology users--to educational technology scholars and practitioners. It describes Asian-Americans' admirable levels of educational…

The unique character of traditional forest-related knowledge: threats and challenges ahead

Treesearch

Ronald L. Trosper; John A. Parrotta; Mauro Agnoletti; Vladimir Bocharnikov; Suzanne A. Feary; Monica Gabay; Christian Gamborg; Jesus García Latorre; Elisabeth Johann; Andrey Laletin; Hin Fui Lim; Alfred Oteng-Yeboah; Miguel A. Pinedo-Vasquez; P.S. Ramakrishnan; Yeo-Chang Youn

2012-01-01

This chapter refl ects on the major fi ndings of the lead authors of this book regarding traditional forest-related knowledge (TFRK) using five criteria for distinguishing the unique character of traditional knowledge: (1) its attention to sustainability; (2) relationships to land; (3) identity; (4) reciprocity; and (5) limitations on market involvement. Following an...

Unlocking Women's Leadership Potential: A Curricular Example for Developing Female Leaders in Academia

ERIC Educational Resources Information Center

Knipfer, Kristin; Shaughnessy, Brooke; Hentschel, Tanja; Schmid, Ellen

2017-01-01

Women in academia face unique challenges when it comes to advancing to professorship. Using latest research about gender and academic leadership, we present a training curriculum that is sensitive to the unique demands of women in and aspiring to leadership positions in academia. The context-specific and evidence-based approach and a focus on…

An Analysis of the Impact of Financial Factors on the Well-Being of Military Officers

DTIC Science & Technology

2015-12-01

34 Figure 18. Job Fields of Participants ...........................................................................34 Figure 19...financial environment as their civilian counterparts, but with some unique challenges and unique benefits. Benefits include relative job stability...instruction goes on to state that personal financial management services shall support the commander, promote readiness and retention , include education

What Is Different about Deaf Education? The Effects of Child and Family Factors on Educational Services

ERIC Educational Resources Information Center

Luft, Pamela

2017-01-01

Deaf education is characterized by several distinctive aspects, beginning with qualities unique to deaf and hard-of-hearing (DHH) children and their families. Consisting of approximately 1.2% of the special education K-12 population, educational and disability systems often struggle to meet the unique challenges that these children and their…

Another Tool in the Belt: Self-Directed Professional Learning for Teachers of Students with Moderate and Severe Disabiliites

ERIC Educational Resources Information Center

Shurr, Jordan; Hirth, Marilyn; Jasper, Andrea; McCollow, Meaghan; Heroux, JoDell

2014-01-01

Chronic shortages, high attrition rates, the unique demands of the job, and geographic isolation from colleagues have been identified as unique challenges within the profession for teachers of students with moderate and severe disabilities. Many different forms of professional development exist for educators; however, these experiences do not…

The Emergence of Hybrid Role Conflict in Conflicting Settings: A Unique Challenge for School Leaders

ERIC Educational Resources Information Center

Nir, Adam E.

2011-01-01

To what extent do divided cities characterized by geopolitical conflicts and a variety of contradictory expectations create a distinctive context and a unique professional conflict for individuals holding boundary-spanning roles? Data collected in a set of in-depth interviews conducted with school principals leading Arab schools located in East…

Tech-Prep in New York State: Profiles of Four Diverse Programs.

ERIC Educational Resources Information Center

Frenkel, Michael W.; Brodsky, Stanley M.

These case studies highlight the diversity of four tech programs that responded with a unique set of organizational policies and procedures to a unique set of challenges. The case study on City Tech Tech-Prep Consortium in Brooklyn focuses on three strategies: transition to City Tech program, postsecondary component, and program evaluation. The…

Unique challenges of hospice for patients with heart failure: A qualitative study of hospice clinicians.

PubMed

Lum, Hillary D; Jones, Jacqueline; Lahoff, Dana; Allen, Larry A; Bekelman, David B; Kutner, Jean S; Matlock, Daniel D

2015-09-01

Patients with heart failure have end-of-life care needs that may benefit from hospice care. The goal of this descriptive study was to understand hospice clinicians' perspectives on the unique aspects of caring for patients with heart failure to inform approaches to improving end-of-life care. This qualitative study explored experiences, observations, and perspectives of hospice clinicians regarding hospice care for patients with heart failure. Thirteen hospice clinicians from a variety of professional disciplines and clinical roles, diverse geographic regions, and varying lengths of time working in hospice participated in semistructured interviews. Through team-based, iterative qualitative analysis, we identified 3 major themes. Hospice clinicians identified 3 themes regarding care for patients with heart failure. First, care for patients with heart failure involves clinical complexity and a tailored approach to cardiac medications and advanced cardiac technologies. Second, hospice clinicians describe the difficulty patients with heart failure have in trusting hospice care due to patient optimism, prognostic uncertainty, and reliance on prehospice health care providers. Third, hospice clinicians described opportunities to improve heart failure-specific hospice care, highlighting the desire for collaboration with referring cardiologists. From a hospice clinician perspective, caring for patients with heart failure is unique compared with other hospice populations. This study suggests potential opportunities for hospice clinicians and referring providers who seek to collaborate to improve care for patients with heart failure during the transition to hospice care. Published by Elsevier Inc.

Low-Frequency Shear and Layer-Breathing Modes in Raman Scattering of Two-Dimensional Materials.

PubMed

Liang, Liangbo; Zhang, Jun; Sumpter, Bobby G; Tan, Qing-Hai; Tan, Ping-Heng; Meunier, Vincent

2017-12-26

Ever since the isolation of single-layer graphene in 2004, two-dimensional layered structures have been among the most extensively studied classes of materials. To date, the pool of two-dimensional materials (2DMs) continues to grow at an accelerated pace and already covers an extensive range of fascinating and technologically relevant properties. An array of experimental techniques have been developed and used to characterize and understand these properties. In particular, Raman spectroscopy has proven to be a key experimental technique, thanks to its capability to identify minute structural and electronic effects in nondestructive measurements. While high-frequency (HF) intralayer Raman modes have been extensively employed for 2DMs, recent experimental and theoretical progress has demonstrated that low-frequency (LF) interlayer Raman modes are more effective at determining layer numbers and stacking configurations and provide a unique opportunity to study interlayer coupling. These advantages are due to 2DMs' unique interlayer vibration patterns where each layer behaves as an almost rigidly moving object with restoring forces corresponding to weak interlayer interactions. Compared to HF Raman modes, the relatively small attention originally devoted to LF Raman modes is largely due to their weaker signal and their proximity to the strong Rayleigh line background, which previously made their detection challenging. Recent progress in Raman spectroscopy with technical and hardware upgrades now makes it possible to probe LF modes with a standard single-stage Raman system and has proven crucial to characterize and understand properties of 2DMs. Here, we present a comprehensive and forward-looking review on the current status of exploiting LF Raman modes of 2DMs from both experimental and theoretical perspectives, revealing the fundamental physics and technological significance of LF Raman modes in advancing the field of 2DMs. We review a broad array of materials, with varying thickness and stacking configurations, discuss the effect of in-plane anisotropy, and present a generalized linear chain model and interlayer bond polarizability model to rationalize the experimental findings. We also discuss the instrumental improvements of Raman spectroscopy to enhance and separate LF Raman signals from the Rayleigh line. Finally, we highlight the opportunities and challenges ahead in this fast-developing field.

Web-Scale Search-Based Data Extraction and Integration

DTIC Science & Technology

2011-10-17

differently, posing challenges for aggregating this information. For example, for the task of finding population for cities in Benin, we were faced with...merged record. Our GeoMerging algorithm attempts to address various ambiguity challenges : • For name: The name of a hospital is not a unique...departments in the same building. For agent-extractor results from structured sources, our GeoMerging algorithm overcomes these challenges using a two

A proposed reductionist solution to address the methodological challenges of inconsistent reflexology maps and poor experimental controls in reflexology research: a discussion paper.

PubMed

Jones, Jenny; Thomson, Patricia; Lauder, William; Leslie, Stephen J

2013-03-01

Reflexology is a complex massage intervention, based on the concept that specific areas of the feet (reflex points) correspond to individual internal organs within the body. Reflexologists trained in the popular Ingham reflexology method claim that massage to these points, using massage techniques unique to reflexology, stimulates an increase in blood supply to the corresponding organ. Reflexology researchers face two key methodological challenges that need to be addressed if a specific treatment-related hemodynamic effect is to be scientifically demonstrated. The first is the problem of inconsistent reflexology foot maps; the second is the issue of poor experimental controls. This article proposes a potential experimental solution that we believe can address both methodological challenges and in doing so, allow any specific hemodynamic treatment effect unique to reflexology to experimentally reveal itself.

Follicular thyroid cancer and Hürthle cell carcinoma: challenges in diagnosis, treatment, and clinical management.

PubMed

Grani, Giorgio; Lamartina, Livia; Durante, Cosimo; Filetti, Sebastiano; Cooper, David S

2018-06-01

Follicular thyroid cancer is the second most common differentiated thyroid cancer histological type and has been overshadowed by its more common counterpart-papillary thyroid cancer-despite its unique biological behaviour and less favourable outcomes. In this Review, we comprehensively review the literature on follicular thyroid cancer to provide an evidence-based guide to the management of these tumours, to highlight the lack of evidence behind guideline recommendations, and to identify changes and challenges over the past decades in diagnosis, prognosis, and treatment. We highlight that correct identification of cancer in indeterminate cytological samples is challenging and ultrasonographic features can be misleading. Despite certain unique aspects of follicular thyroid cancer presentation and prognosis, no specific recommendations exist for follicular thyroid cancer and Hürthle cell carcinoma in evidence-based guidelines. Efforts should be made to stimulate additional research in this field. Copyright © 2018 Elsevier Ltd. All rights reserved.

Lorcaserin: drug profile and illustrative model of the regulatory challenges of weight-loss drug development.

PubMed

Bays, Harold E

2011-03-01

Lorcaserin is a selective 5-hydroxytryptamine receptor 2c agonist developed as a weight-loss drug. Phase II and III clinical trials support lorcaserin as not only reducing adiposity (i.e., fat mass), but also as improving the metabolic diseases commonly associated with adiposopathy (i.e., fat dysfunction). At the time of this writing, regulatory processes continue towards evaluating lorcaserin as a potentially marketed weight-loss and weight-maintenance agent. Some of the challenges facing lorcaserin are similar to the difficulties encountered by all investigational weight-loss therapeutic agents, which include evolving paths towards approval. While important for clinicians to understand approval hurdles for all therapeutics, it is especially critical for researchers and developers to grasp the unique regulatory complexities of anti-obesity agents. This article profiles lorcaserin as an illustrative example of general drug development regulatory processes, and specifically details the unique challenge of weight-loss drug development.

Methane Leak Detection and Emissions Quantification with UAVs

NASA Astrophysics Data System (ADS)

Barchyn, T.; Fox, T. A.; Hugenholtz, C.

2016-12-01

Robust leak detection and emissions quantification algorithms are required to accurately monitor greenhouse gas emissions. Unmanned aerial vehicles (UAVs, `drones') could both reduce the cost and increase the accuracy of monitoring programs. However, aspects of the platform create unique challenges. UAVs typically collect large volumes of data that are close to source (due to limited range) and often lower quality (due to weight restrictions on sensors). Here we discuss algorithm development for (i) finding sources of unknown position (`leak detection') and (ii) quantifying emissions from a source of known position. We use data from a simulated leak and field study in Alberta, Canada. First, we detail a method for localizing a leak of unknown spatial location using iterative fits against a forward Gaussian plume model. We explore sources of uncertainty, both inherent to the method and operational. Results suggest this method is primarily constrained by accurate wind direction data, distance downwind from source, and the non-Gaussian shape of close range plumes. Second, we examine sources of uncertainty in quantifying emissions with the mass balance method. Results suggest precision is constrained by flux plane interpolation errors and time offsets between spatially adjacent measurements. Drones can provide data closer to the ground than piloted aircraft, but large portions of the plume are still unquantified. Together, we find that despite larger volumes of data, working with close range plumes as measured with UAVs is inherently difficult. We describe future efforts to mitigate these challenges and work towards more robust benchmarking for application in industrial and regulatory settings.

Echocardiographic evaluation of right ventricular systolic function: The traditional and innovative approach.

PubMed

Smolarek, Dorota; Gruchała, Marcin; Sobiczewski, Wojciech

2017-01-01

Estimation of right ventricular (RV) performance still remains technically challenging due to its anatomical and functional distinctiveness. The current guidelines for the echocardiographic quantification of RV function recommend using multiple indices to describe the RV in a thorough and comprehensive manner, such as RV index of myocardial performance, tricuspid annular plane systolic excursion, fractional area change, Doppler tissue imaging-derived tricuspid lateral annular systolic velocity (S'-wave), three-dimensional RV ejection fraction (3D RVEF), RV longitudinal strain (RVLS)/strain rate by speckle- tracking echocardiography (STE). Among these, the last one mentioned here is an innovative and a particularly promising tool that yields more precise information about complex regional and global RV mechanics. STE was initially designed to evaluate left ventricular function, but recently it has been introduced to assess RV performance, which is difficult due to its unique structure and physiology. Many studies have shown that both free wall and 6-segment RVLS present a stronger correlation with the RVEF assessed by cardiac magnetic resonance than conventional parameters and seem to be more sensitive in detecting myocardial dysfunction at an earlier, subclinical stage.

Simple thermal to thermal face verification method based on local texture descriptors

NASA Astrophysics Data System (ADS)

Grudzien, A.; Palka, Norbert; Kowalski, M.

2017-08-01

Biometrics is a science that studies and analyzes physical structure of a human body and behaviour of people. Biometrics found many applications ranging from border control systems, forensics systems for criminal investigations to systems for access control. Unique identifiers, also referred to as modalities are used to distinguish individuals. One of the most common and natural human identifiers is a face. As a result of decades of investigations, face recognition achieved high level of maturity, however recognition in visible spectrum is still challenging due to illumination aspects or new ways of spoofing. One of the alternatives is recognition of face in different parts of light spectrum, e.g. in infrared spectrum. Thermal infrared offer new possibilities for human recognition due to its specific properties as well as mature equipment. In this paper we present the scheme of subject's verification methodology by using facial images in thermal range. The study is focused on the local feature extraction methods and on the similarity metrics. We present comparison of two local texture-based descriptors for thermal 1-to-1 face recognition.

Genetic testing and genetic counseling in patients with sudden death risk due to heritable arrhythmias.

PubMed

Spoonamore, Katherine G; Ware, Stephanie M

2016-03-01

Sudden cardiac death due to heritable ventricular arrhythmias is an important cause of mortality, especially in young healthy individuals. The identification of the genetic basis of Mendelian diseases associated with arrhythmia has allowed the integration of this information into the diagnosis and clinical management of patients and at-risk family members. The rapid expansion of genetic testing options and the increasing complexity involved in the interpretation of results creates unique opportunities and challenges. There is a need for competency to incorporate genetics into clinical management and to provide appropriate family-based risk assessment and information. In addition, disease-specific genetic knowledge is required to order and correctly interpret and apply genetic testing results. Importantly, genetic diagnosis has a critical role in the risk stratification and clinical management of family members. This review summarizes the approach to genetic counseling and genetic testing for inherited arrhythmias and highlights specific genetic principles that apply to long QT syndrome, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Incidence and prevalence of pregnancy-related heart disease.

PubMed

Sliwa, Karen; Böhm, Michael

2014-03-15

Worldwide, the numbers of women who have a pre-existing cardiovascular disease or develop cardiac problems during pregnancy are increasing and, due to the lack of evidenced-based data, this provides challenges for the treating physician. Cardiovascular disease in pregnancy is a complex topic as women can present either pre- or post-partum, due to a pre-existing heart disease such as operated on or unoperated on congenital heart disease, valvular heart disease, chronic hypertension, or familial dilated cardiomyopathy. Women often present with symptoms and signs of acute heart failure. On the other hand, there are diseases which are directly related to pregnancy, such as hypertensive disorders of pregnancy and peripartum cardiomyopathy, or where pregnancy increases risk of a disease as, for example, the risk of myocardial infarction. These diseases can have long-term implications to the life of the affected women and their families. There is, in particular, a paucity of data from developing countries of this unique disease pattern and its presentations. This review summarizes the current knowledge of the incidence and prevalence of pregnancy-related cardiovascular disease in women presenting pre- or post-partum.

Flexible and stretchable electronics for wearable healthcare devices and minimally invasive surgical tools

NASA Astrophysics Data System (ADS)

Kim, Dae-Hyeong; Lee, Mincheol; Lee, Hyunjae

2016-05-01

Recent advances in soft electronics have attracted great attention, largely due to their potential applications in personalized, bio-integrated healthcare devices. The mechanical mismatch between conventional electronic/optoelectronic devices and soft human tissues/organs have presented many challenges, such as the low signalto- noise ratio of biosensors because of the incomplete integration of rigid devices with the body, inflammation and excessive immune responses of implanted stiff devices originated from friction and their foreign nature to biotic systems, and the considerable discomfort and consequent stress experienced by users when wearing/implanting these devices. Ultra-flexible and stretchable electronic devices are being highlighted due to their low system modulus and the intrinsic system-level softness that are important to solve these issues. Here, we describe our unique strategies for the nanomaterial synthesis and fabrication, their seamless assembly and integration, and the design and development of corresponding wearable healthcare devices and minimally invasive surgical tools. These bioelectronic systems fully utilize recent breakthroughs in unconventional soft electronics based on nanomaterials to address unsolved issues in clinical medicine and to provide new opportunities in the personalized healthcare.

Nanoparticles-Based Systems for Osteochondral Tissue Engineering.

PubMed

Oliveira, Isabel; Vieira, Sílvia; Oliveira, J Miguel; Reis, Rui L

2018-01-01

Osteochondral lesions represent one of the major causes of disabilities in the world. These defects are due to degenerative or inflammatory arthritis, but both affect the articular cartilage and the underlying subchondral bone. Defects from trauma or degenerative pathology frequently cause severe pain, joint deformity, and loss of joint motion. Osteochondral defects are a significant challenge in orthopedic surgery, due to the cartilage complexity and unique structure, as well as its exposure to high pressure and motion. Although there are treatments routinely performed in the clinical practice, they present several limitations. Tissue engineering can be a suitable alternative for osteochondral defects since bone and cartilage engineering had experienced a notable advance over the years. Allied with nanotechnology, osteochondral tissue engineering (OCTE) can be leveled up, being possible to create advanced structures similar to the OC tissue. In this chapter, the current strategies using nanoparticles-based systems are overviewed. The results of the studies herein considered confirm that advanced nanomaterials will undoubtedly play a crucial role in the design of strategies for treatment of osteochondral defects in the near future.

Assessing downstream flood impacts due to a potential GLOF from Imja Tsho in Nepal

NASA Astrophysics Data System (ADS)

Somos-Valenzuela, M. A.; McKinney, D. C.; Byers, A. C.; Rounce, D. R.; Portocarrero, C.; Lamsal, D.

2015-03-01

Glacial-dominated areas pose unique challenges to downstream communities in adapting to recent and continuing global climate change, including increased threats of glacial lake outburst floods (GLOFs) that can increase risk due to flooding of downstream communities and cause substantial impacts on regional social, environmental and economic systems. The Imja glacial lake (or Imja Tsho) in Nepal, which has the potential to generate a GLOF, was studied using a two-dimensional debris-flow inundation model in order to evaluate the effectiveness of proposed measures to reduce possible flooding impacts to downstream communities by lowering the lake level. The results indicate that only minor flood impact reduction is achieved in the downstream community of Dingboche with modest (~3 m) lake lowering. Lowering the lake by 10 m shows a significant reduction in inundated area. However, lowering the lake by 20 m almost eliminates all flood impact at Dingboche. Further downstream at Phakding, the impact of the GLOF is significant and similar reductions in inundation are likely as a result of lake lowering.

4D-tomographic reconstruction of water vapor using the hybrid regularization technique with application to the North West of Iran

NASA Astrophysics Data System (ADS)

Adavi, Zohre; Mashhadi-Hossainali, Masoud

2015-04-01

Water vapor is considered as one of the most important weather parameter in meteorology. Its non-uniform distribution, which is due to the atmospheric phenomena above the surface of the earth, depends both on space and time. Due to the limited spatial and temporal coverage of observations, estimating water vapor is still a challenge in meteorology and related fields such as positioning and geodetic techniques. Tomography is a method for modeling the spatio-temporal variations of this parameter. By analyzing the impact of troposphere on the Global Navigation Satellite (GNSS) signals, inversion techniques are used for modeling the water vapor in this approach. Non-uniqueness and instability of solution are the two characteristic features of this problem. Horizontal and/or vertical constraints are usually used to compute a unique solution for this problem. Here, a hybrid regularization method is used for computing a regularized solution. The adopted method is based on the Least-Square QR (LSQR) and Tikhonov regularization techniques. This method benefits from the advantages of both the iterative and direct techniques. Moreover, it is independent of initial values. Based on this property and using an appropriate resolution for the model, firstly the number of model elements which are not constrained by GPS measurement are minimized and then; water vapor density is only estimated at the voxels which are constrained by these measurements. In other words, no constraint is added to solve the problem. Reconstructed profiles of water vapor are validated using radiosonde measurements.

Mechanical Behavior of Al-SiC Nanolaminate Composites Using Micro-Scale Testing Methods

NASA Astrophysics Data System (ADS)

Mayer, Carl Randolph

Nanolaminate composite materials consist of alternating layers of materials at the nanoscale (≤100 nm). Due to the nanometer scale thickness of their layers, these materials display unique and tailorable properties. This enables us to alter both mechanical attributes such as strength and wear properties, as well as functional characteristics such as biocompatibility, optical, and electronic properties. This dissertation focuses on understanding the mechanical behavior of the Al-SiC system. From a practical perspective, these materials exhibit a combination of high toughness and strength which is attractive for many applications. Scientifically, these materials are interesting due to the large elastic modulus mismatch between the layers. This, paired with the small layer thickness, allows a unique opportunity for scientists to study the plastic deformation of metals under extreme amounts of constraint. Previous studies are limited in scope and a more diverse range of mechanical characterization is required to understand both the advantages and limitations of these materials. One of the major challenges with testing these materials is that they are only able to be made in thicknesses on the order of micrometers so the testing methods are limited to small volume techniques. This work makes use of both microscale testing techniques from the literature as well as novel methodologies. Using these techniques we are able to gain insight into aspects of the material's mechanical behavior such as the effects of layer orientation, flaw dependent fracture, tension-compression asymmetry, fracture toughness as a function of layer thickness, and shear behavior as a function of layer thickness.

Using Java to generate globally unique identifiers for DICOM objects.

PubMed

Kamauu, Aaron W C; Duvall, Scott L; Avrin, David E

2009-03-01

Digital imaging and communication in medicine (DICOM) specifies that all DICOM objects have globally unique identifiers (UIDs). Creating these UIDs can be a difficult task due to the variety of techniques in use and the requirement to ensure global uniqueness. We present a simple technique of combining a root organization identifier, assigned descriptive identifiers, and JAVA generated unique identifiers to construct DICOM compliant UIDs.

Proteoglycomics: Recent Progress and Future Challenges

PubMed Central

Ly, Mellisa; Laremore, Tatiana N.

2010-01-01

Abstract Proteoglycomics is a systematic study of structure, expression, and function of proteoglycans, a posttranslationally modified subset of a proteome. Although relying on the established technologies of proteomics and glycomics, proteoglycomics research requires unique approaches for elucidating structure–function relationships of both proteoglycan components, glycosaminoglycan chain, and core protein. This review discusses our current understanding of structure and function of proteoglycans, major players in the development, normal physiology, and disease. A brief outline of the proteoglycomic sample preparation and analysis is provided along with examples of several recent proteoglycomic studies. Unique challenges in the characterization of glycosaminoglycan component of proteoglycans are discussed, with emphasis on the many analytical tools used and the types of information they provide. PMID:20450439

Implications and challenges for implementation of the FDA’s final deeming rule for waterpipe tobacco

PubMed Central

Sutfin, Erin L; Soule, Eric K; McKelvey, Karma; Jenson, Desmond

2017-01-01

For the first time, the Food and Drug Administration’s (FDAs) Center for Tobacco Products now has regulatory authority over all tobacco products, including waterpipe tobacco. In the rule expanding its authority to cover all tobacco products, the FDA uses largely a one-size-fits-all approach. However, several aspects of waterpipe tobacco smoking make it unique from other tobacco products, which may require more specific, tailored rules. This paper describes the distinct features of waterpipe tobacco products and accessories, and identifies unique challenges to the current regulation posed by this form of tobacco use. Additionally, we highlight the need for further research-generated evidence to support additional rulemaking. PMID:28667092

A proposed UAV for indoor patient care.

PubMed

Todd, Catherine; Watfa, Mohamed; El Mouden, Yassine; Sahir, Sana; Ali, Afrah; Niavarani, Ali; Lutfi, Aoun; Copiaco, Abigail; Agarwal, Vaibhavi; Afsari, Kiyan; Johnathon, Chris; Okafor, Onyeka; Ayad, Marina

2015-09-10

Indoor flight, obstacle avoidance and client-server communication of an Unmanned Aerial Vehicle (UAV) raises several unique research challenges. This paper examines current methods and associated technologies adapted within the literature toward autonomous UAV flight, for consideration in a proposed system for indoor healthcare administration with a quadcopter. We introduce Healthbuddy, a unique research initiative towards overcoming challenges associated with indoor navigation, collision detection and avoidance, stability, wireless drone-server communications and automated decision support for patient care in a GPS-denied environment. To address the identified research deficits, a drone-based solution is presented. The solution is preliminary as we develop and refine the suggested algorithms and hardware system to achieve the research objectives.

The challenge of doing science in wilderness: historical, legal, and policy context

Treesearch

Peter Landres; Judy Alderson; David J. Parsons

2003-01-01

Lands designated by Congress under the Wilderness Act of 1964 (Public Law 88-577) offer unique opportunities for social and biophysical research in areas that are relatively unmodified by modern human actions. Wilderness designation also imposes a unique set of constraints on the methods that may be used or permitted to conduct this research. For example, legislated...

Taking Care of You: Body, Mind, Spirit--A Unique Stress Management Program That Improves Lifestyle Behaviors

ERIC Educational Resources Information Center

Vetter-Smith, Molly; Massey, Vera; Rellergert, Linda; Wissmann, Mary

2014-01-01

Taking Care of You: Body, Mind, Spirit is a multi-session group program developed by University of Missouri Extension that provides a unique and practical approach to helping adults better managing their stress and bounce back from life's challenges while improving lifestyle behaviors. The program combines mindfulness and a variety of other…

A Unique Sequence of Financial Accounting Courses Featuring Team Teaching, Linked Courses, Challenging Assignments, and Instruments for Evaluation and Assessment

ERIC Educational Resources Information Center

Lundblad, Heidemarie; Wilson, Barbara A.

2008-01-01

The Department of Accounting at California State University Northridge (CSUN) has developed a unique sequence of courses designed to ensure that accounting students are trained not only in technical accounting, but also acquire critical thinking, research and communication skills. The courses have proven effective and have embedded assessment…

Starting small: Revisiting young children's perceptions of social withdrawal in China.

PubMed

Ding, Xuechen; Coplan, Robert J; Sang, Biao; Liu, Junsheng; Pan, Tingting; Cheng, Chen

2015-06-01

In this reply to the commentaries by Xinyin Chen, Charissa Cheah, Yiyuan Xu, and Dawn Watling, we further discuss the conceptual and methodological challenges that arise when attempting to study beliefs about social withdrawal (1) in the unique cultural context of China and (2) in the unique developmental age period of early childhood. © 2015 The British Psychological Society.

Psychological aspects of human cloning and genetic manipulation: the identity and uniqueness of human beings.

PubMed

Morales, N M

2009-01-01

Human cloning has become one of the most controversial debates about reproduction in Western civilization. Human cloning represents asexual reproduction, but the critics of human cloning argue that the result of cloning is not a new individual who is genetically unique. There is also awareness in the scientific community, including the medical community, that human cloning and the creation of clones are inevitable. Psychology and other social sciences, together with the natural sciences, will need to find ways to help the healthcare system, to be prepared to face the new challenges introduced by the techniques of human cloning. One of those challenges is to help the healthcare system to find specific standards of behaviour that could be used to help potential parents to interact properly with cloned babies or children created through genetic manipulation. In this paper, the concepts of personality, identity and uniqueness are discussed in relationship to the contribution of twin studies in these areas. The author argues that an individual created by human cloning techniques or any other type of genetic manipulation will not show the donor's characteristics to the extent of compromising uniqueness. Therefore, claims to such an effect are needlessly alarmist.

Perceptions of ESL Program Management in Canadian Higher Education: A Qualitative Case Study

ERIC Educational Resources Information Center

Eaton, Sarah Elaine

2017-01-01

ESL programs at post-secondary institutions must often generate revenue in addition to teaching students English. Institutions often impose explicit expectations on these programs to generate profit, creating unique challenges for those who administer them. This qualitative case study investigated challenges faced by ESL program directors at one…

Adult English Language Learners with Limited Literacy

ERIC Educational Resources Information Center

Bigelow, Martha; Schwarz, Robin Lovrien

2010-01-01

Adult English language learners who lack print literacy or experience with formal education encounter a unique set of challenges in their lives and their efforts to learn English. Educators and policymakers are similarly challenged by how best to help these adults acquire English literacy. This paper reviews a variety of research, including that…

Interventions for Children with Autism Spectrum Disorders in Inclusive School Settings

ERIC Educational Resources Information Center

Koegel, Lynn; Matos-Freden, Rosy; Lang, Russell; Koegel, Robert

2012-01-01

Students with ASD present unique challenges to school systems. Despite these challenges, federal laws require that schools implement research-based practices in the least restrictive environment (LRE). The LRE is often deemed to be the general education classroom and the primary intervention agent is often the classroom teacher. Ensuring students…

Social media as a platform for science and health engagement: challenges and opportunities.

PubMed

Dixon, Graham

2016-01-01

Social media has become a major platform for debates on science and health. This commentary argues that while social media can present challenges to communicating important health matters, it can also provide health experts a unique opportunity to engage with and build trust among members of the public.

Tenured Women Counselor Educators at Research Universities: Navigating Multiple Roles and Personal Well-Being

ERIC Educational Resources Information Center

Rosenberg, Melissa A.

2013-01-01

Women in academia navigate multiple professional and personal roles, and may face unique challenges to integrate their intellectual, emotional, physical, and spiritual selves. The narrative of constraint underscores the disadvantages, challenges, and inequities that women who are mothers and academics face in their lives. This lack of privilege…

Building an Academe and Government Partnership in Workforce Education: Challenges and Possibilities

ERIC Educational Resources Information Center

Kearney, Kerri S.; Self, Mary Jo; Bailey, Lucy; Harris, Ed; Halcomb, Starla; Hill, Brent; Shimp, Upton

2007-01-01

In 2004, the College of Education at Oklahoma State University began the task of building a partnership with the Defense Ammunition Center (DAC) in McAlester, Oklahoma, and implementing research-driven, experience-based workforce education. In this article, the authors describe unique features and challenges of this multi-year…

Counselling in Primary Care: Past, Present, and Future.

ERIC Educational Resources Information Center

Eatock, John

2000-01-01

Presents a brief history of the growth of counseling in primary care. Discusses the challenges for primary care counselors and counseling, as well as the need for coordination, regulation and management. Also discusses the imperative for research support and the unique nature of counseling in primary care including challenges to its survival. (MKA)

Teaching Children to Understand Operations in Early Childhood

ERIC Educational Resources Information Center

Ladhams, Jan

2005-01-01

The author discusses teaching early child mathematics in an environment of unique challenge in a remote region of Western Australia. The challenges include: (1) a high proportion of transient students; (2) a student population that is forty percent aboriginal, many for whom English is a second language; (3) students who consistently perform below…

Do We Expect Too Much of Bilingual Teachers? Bilingual Teaching in Developing Countries

ERIC Educational Resources Information Center

Benson, Carol

2004-01-01

Given the unique character of bilingual students and the programmes that support them, primary bilingual teaching is a challenging job in any country. However, bilingual teachers in developing contexts are especially challenged; they are often undertrained and underpaid, and must function in under-resourced schools with undernourished students.…

Active Learning: Engaging Students to Maximize Learning in an Online Course

ERIC Educational Resources Information Center

Khan, Arshia; Egbue, Ona; Palkie, Brooke; Madden, Janna

2017-01-01

Student engagement is key to successful teaching and learning, irrespective of the content and format of the content delivery mechanism. However, engaging students presents a particular challenge in online learning environments. Unlike face-to-face courses, online courses present a unique challenge as the only social presence between the faculty…

Using School Change States to Analyze Comprehensive School Reform Projects

ERIC Educational Resources Information Center

Wetherill, Karen S.; Applefield, James M.

2005-01-01

Comprehensive school reform (CSR) projects are being funded throughout the United States in a determined effort to improve the performance of public education. The multidimensional nature of comprehensive school reform presents unique challenges for explaining widely discrepant outcomes among schools. These challenges are addressed in a study of 8…

Forming an Institutional Culture with Multinational Administrators and Teachers at Effat College, Saudi Arabia

ERIC Educational Resources Information Center

Glowacki-Dudka, Michelle; Treff, Marjorie

2011-01-01

This article describes the teaching and learning culture of a newly established women's college in Jeddah, Saudi Arabia. The academic culture at Effat College in 2002 included administrators and teachers from many nations, which created unique challenges in cross-cultural communication. These challenges, in turn, affected the development and…

Boundary-Spanning Actors in Urban 4-H: An Action Research Case Study

ERIC Educational Resources Information Center

David, Victoria Dotson

2014-01-01

Today's Cooperative Extension organization continues to face challenges of providing relevant, quality programming in urban communities. Challenges include the ability to build capacity in Extension's urban youth educators to assess and interpret the unique, variable needs of urban clients and to communicate effectively the identified…

Leadership for Rural Schools: Lessons for All Educators.

ERIC Educational Resources Information Center

Chalker, Donald M., Ed.

Rural schools present unique challenges for school administrators, challenges that require knowledge of various skills in a range of disciplines. This book touches nearly every aspect of rural school leadership. It aims to help educational leaders in small or rural schools better understand their role, and to help all educators learn elements of…

Creating Learning Momentum through Overt Teaching Interactions during Real Acute Care Episodes

ERIC Educational Resources Information Center

Piquette, Dominique; Moulton, Carol-Anne; LeBlanc, Vicki R.

2015-01-01

Clinical supervisors fulfill a dual responsibility towards patient care and learning during clinical activities. Assuming such roles in today's clinical environments may be challenging. Acute care environments present unique learning opportunities for medical trainees, as well as specific challenges. The goal of this paper was to better understand…

Overcoming the glass ceiling: views from the cellar and the roof.

PubMed

McCrady, Barbara S

2012-12-01

Women's experiences as professionals and behavior therapists have changed considerably in the past 40 years. The author describes early challenges and experiences of discrimination as a young female professional. Although women's opportunities have improved considerably, women still experience unique career challenges and choices. The author provides some suggestions for women's career development.

Landing the Job: How Special Libraries Can Support Career Research Introduction

ERIC Educational Resources Information Center

Howard, Heather

2017-01-01

"Special Libraries, Special Challenges" is a column dedicated to exploring the unique public services challenges that arise in libraries that specialize in a particular subject, such as law, medicine, business, and so forth. In each column, the author will discuss public service dilemmas and opportunities that arise in special libraries.…

Understanding Planned Change among Remote Nonfaculty Employees in Higher Education

ERIC Educational Resources Information Center

Lubin, Erin Heather

2017-01-01

Implementing planned change in online university divisions with remote nonfaculty employees is a unique challenge. The problem that compelled this study was the need to understand the challenges of implementing planned change for a group of geographically remote nonfaculty employees who served as field team members (FTM) in an online university's…

Commentary: Challenging Views and Creative Insights from a Social Cultural Perspective

ERIC Educational Resources Information Center

Hui, Anna N. N.

2015-01-01

This commentary focuses on the challenging views and creative insights inspired by the four articles in this special issue of the journal. The studies have integrated creativity research with social psychological and cultural perspectives. I have highlighted the unique contribution of how Karwowski, Tanggaard, Glaveanu, and Hennessey have each…

Managing Student Behavior in an Elementary School Music Classroom: A Study of Class-Wide Function-Related Intervention Teams

ERIC Educational Resources Information Center

Caldarella, Paul; Williams, Leslie; Jolstead, Krystine A.; Wills, Howard P.

2017-01-01

Classroom management is a common concern for teachers. Music teachers in particular experience unique behavior challenges because of large class sizes, uncommon pacing requirements, and performance-based outcomes. Positive behavior support is an evidence-based framework for preventing or eliminating challenging behaviors by teaching and…

Career Development with Transgender College Students: Implications for Career and Employment Counselors

ERIC Educational Resources Information Center

Scott, David A.; Belke, Stephanie L.; Barfield, Hannah G.

2011-01-01

The number of transgender college students continues to increase every year. These students face unique challenges that many college and university career centers are not prepared to handle. This article describes some of the challenges facing transgender students and college career centers. A professional development design is proposed to assist…

A Better Tomorrow: Examination of International Students' Success in Higher Education

ERIC Educational Resources Information Center

Shen, Yue

2017-01-01

International student enrollment in U.S. higher education has increased and diversified over the past decade. The unique needs and challenges international students face in pursuing higher education in the U.S. need a systematic investigation. Previous research literature has identified cultural diversity as one main challenge against…

Life Journey through Autism: A Guide for Military Families

ERIC Educational Resources Information Center

Alexander, Katie C.; Clemens, Erin M.; Gilbert, Marilyn; McBreen, Joseph

2010-01-01

Autism presents parents and families with many challenges under normal circumstances. Autism in a military family magnifies many of those challenges and adds a few more that are unique to the demands of military life and service, further complicating an already complex neurobiological disorder. Military sources indicate that more than 13,000…

Impact of Military Lifestyle on Military Spouses' Educational and Career Goals

ERIC Educational Resources Information Center

Ott, Laura E.; Kellley Morgan, Jessica; Akroyd, H. Duane

2018-01-01

The military lifestyle imposes unique challenges for military spouses in regards to their education and careers. To help alleviate these challenges, military spouses are encouraged to pursue portable career paths. This causes one to question whether spouses desire these portable careers and what influences spouses place on pursuing specific…

Business Process Reengineering towards an Integrated Learning Management System

ERIC Educational Resources Information Center

Basal, Abdelraheem Mousa

2010-01-01

The task of managing an information technology (IT) system in a school environment poses unique challenges. For example, one of the greatest challenges facing individual schools is the lack of integration among various information systems. The present situation in many schools is that there are many disconnected systems managing many different…

Benchmarking neuromorphic vision: lessons learnt from computer vision

PubMed Central

Tan, Cheston; Lallee, Stephane; Orchard, Garrick

2015-01-01

Neuromorphic Vision sensors have improved greatly since the first silicon retina was presented almost three decades ago. They have recently matured to the point where they are commercially available and can be operated by laymen. However, despite improved availability of sensors, there remains a lack of good datasets, while algorithms for processing spike-based visual data are still in their infancy. On the other hand, frame-based computer vision algorithms are far more mature, thanks in part to widely accepted datasets which allow direct comparison between algorithms and encourage competition. We are presented with a unique opportunity to shape the development of Neuromorphic Vision benchmarks and challenges by leveraging what has been learnt from the use of datasets in frame-based computer vision. Taking advantage of this opportunity, in this paper we review the role that benchmarks and challenges have played in the advancement of frame-based computer vision, and suggest guidelines for the creation of Neuromorphic Vision benchmarks and challenges. We also discuss the unique challenges faced when benchmarking Neuromorphic Vision algorithms, particularly when attempting to provide direct comparison with frame-based computer vision. PMID:26528120

Graphene and its derivatives as biomedical materials: future prospects and challenges.

PubMed

Banerjee, Arghya Narayan

2018-06-06

Graphene and its derivatives possess some intriguing properties, which generates tremendous interests in various fields, including biomedicine. The biomedical applications of graphene-based nanomaterials have attracted great interests over the last decade, and several groups have started working on this field around the globe. Because of the excellent biocompatibility, solubility and selectivity, graphene and its derivatives have shown great potential as biosensing and bio-imaging materials. Also, due to some unique physico-chemical properties of graphene and its derivatives, such as large surface area, high purity, good bio-functionalizability, easy solubility, high drug loading capacity, capability of easy cell membrane penetration, etc., graphene-based nanomaterials become promising candidates for bio-delivery carriers. Besides, graphene and its derivatives have also shown interesting applications in the fields of cell-culture, cell-growth and tissue engineering. In this article, a comprehensive review on the applications of graphene and its derivatives as biomedical materials has been presented. The unique properties of graphene and its derivatives (such as graphene oxide, reduced graphene oxide, graphane, graphone, graphyne, graphdiyne, fluorographene and their doped versions) have been discussed, followed by discussions on the recent efforts on the applications of graphene and its derivatives in biosensing, bio-imaging, drug delivery and therapy, cell culture, tissue engineering and cell growth. Also, the challenges involved in the use of graphene and its derivatives as biomedical materials are discussed briefly, followed by the future perspectives of the use of graphene-based nanomaterials in bio-applications. The review will provide an outlook to the applications of graphene and its derivatives, and may open up new horizons to inspire broader interests across various disciplines.

Advantages and Challenges of Relaxor-PbTiO3 Ferroelectric Crystals for Electroacoustic Transducers- A Review.

PubMed

Zhang, Shujun; Li, Fei; Jiang, Xiaoning; Kim, Jinwook; Luo, Jun; Geng, Xuecang

2015-03-01

Relaxor-PbTiO 3 (PT) based ferroelectric crystals with the perovskite structure have been investigated over the last few decades due to their ultrahigh piezoelectric coefficients ( d 33 > 1500 pC/N) and electromechanical coupling factors ( k 33 > 90%), far outperforming state-of-the-art ferroelectric polycrystalline Pb(Zr,Ti)O 3 ceramics, and are at the forefront of advanced electroacoustic applications. In this review, the performance merits of relaxor-PT crystals in various electroacoustic devices are presented from a piezoelectric material viewpoint. Opportunities come from not only the ultrahigh properties, specifically coupling and piezoelectric coefficients, but through novel vibration modes and crystallographic/domain engineering. Figure of merits (FOMs) of crystals with various compositions and phases were established for various applications, including medical ultrasonic transducers, underwater transducers, acoustic sensors and tweezers. For each device application, recent developments in relaxor-PT ferroelectric crystals were surveyed and compared with state-of-the-art polycrystalline piezoelectrics, with an emphasis on their strong anisotropic features and crystallographic uniqueness, including engineered domain - property relationships. This review starts with an introduction on electroacoustic transducers and the history of piezoelectric materials. The development of the high performance relaxor-PT single crystals, with a focus on their uniqueness in transducer applications, is then discussed. In the third part, various FOMs of piezoelectric materials for a wide range of ultrasound applications, including diagnostic ultrasound, therapeutic ultrasound, underwater acoustic and passive sensors, tactile sensors and acoustic tweezers, are evaluated to provide a thorough understanding of the materials' behavior under operational conditions. Structure-property-performance relationships are then established. Finally, the impacts and challenges of relaxor-PT crystals are summarized to guide on-going and future research in the development of relaxor-PT crystals for the next generation electroacoustic transducers.

Needles in the blue sea: sub-species specificity in targeted protein biomarker analyses within the vast oceanic microbial metaproteome.

PubMed

Saito, Mak A; Dorsk, Alexander; Post, Anton F; McIlvin, Matthew R; Rappé, Michael S; DiTullio, Giacomo R; Moran, Dawn M

2015-10-01

Proteomics has great potential for studies of marine microbial biogeochemistry, yet high microbial diversity in many locales presents us with unique challenges. We addressed this challenge with a targeted metaproteomics workflow for NtcA and P-II, two nitrogen regulatory proteins, and demonstrated its application for cyanobacterial taxa within microbial samples from the Central Pacific Ocean. Using METATRYP, an open-source Python toolkit, we examined the number of shared (redundant) tryptic peptides in representative marine microbes, with the number of tryptic peptides shared between different species typically being 1% or less. The related cyanobacteria Prochlorococcus and Synechococcus shared an average of 4.8 ± 1.9% of their tryptic peptides, while shared intraspecies peptides were higher, 13 ± 15% shared peptides between 12 Prochlorococcus genomes. An NtcA peptide was found to target multiple cyanobacteria species, whereas a P-II peptide showed specificity to the high-light Prochlorococcus ecotype. Distributions of NtcA and P-II in the Central Pacific Ocean were similar except at the Equator likely due to differential nitrogen stress responses between Prochlorococcus and Synechococcus. The number of unique tryptic peptides coded for within three combined oceanic microbial metagenomes was estimated to be ∼4 × 10(7) , 1000-fold larger than an individual microbial proteome and 27-fold larger than the human proteome, yet still 20 orders of magnitude lower than the peptide diversity possible in all protein space, implying that peptide mapping algorithms should be able to withstand the added level of complexity in metaproteomic samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dexmedetomidine for an awake fiber-optic intubation of a parturient with Klippel-Feil syndrome, Type I Arnold Chiari malformation and status post released tethered spinal cord presenting for repeat cesarean section

PubMed Central

Shah, Tanmay H.; Badve, Manasi S.; Olajide, Kowe O.; Skorupan, Havyn M.; Waters, Jonathan H.; Vallejo, Manuel C.

2011-01-01

Patients with Klippel-Feil Syndrome (KFS) have congenital fusion of their cervical vertebrae due to a failure in the normal segmentation of the cervical vertebrae during the early weeks of gestation and also have myriad of other associated anomalies. Because of limited neck mobility, airway management in these patients can be a challenge for the anesthesiologist. We describe a unique case in which a dexmedetomidine infusion was used as sedation for an awake fiber-optic intubation in a parturient with Klippel-Feil Syndrome, who presented for elective cesarean delivery. A 36-year-old female, G2P1A0 with KFS (fusion of cervical vertebrae) who had prior cesarean section for breech presentation with difficult airway management was scheduled for repeat cesarean delivery. After obtaining an informed consent, patient was taken in the operating room and non-invasive monitors were applied. Dexmedetomidine infusion was started and after adequate sedation, an awake fiber-optic intubation was performed. General anesthetic was administered after intubation and dexmedetomidine infusion was continued on maintenance dose until extubation. Klippel-Feil Syndrome (KFS) is a rare congenital disorder for which the true incidence is unknown, which makes it even rare to see a parturient with this disease. Patients with KFS usually have other congenital abnormalities as well, sometimes including the whole thoraco-lumbar spine (Type III) precluding the use of neuraxial anesthesia for these patients. Obstetric patients with KFS can present unique challenges in administering anesthesia and analgesia, primarily as it relates to the airway and dexmedetomidine infusion has shown promising result to manage the airway through awake fiberoptic intubation without any adverse effects on mother and fetus. PMID:24765318

Mesothelium of the Murine Allantois Exhibits Distinct Regional Properties

PubMed Central

Daane, Jacob M.; Enders, Allen C.; Downs, Karen M.

2011-01-01

The rodent allantois is thought to be unique amongst mammals in not having an endodermal component. Here, we have investigated the mesothelium, or outer surface, of murine umbilical precursor tissue, the allantois (~7.25–8.5 days postcoitum, dpc) to discover whether it exhibits the properties of an epithelium. A combination of morphology, challenge with biotinylated dextran amines (BDAs), and immunohistochemistry revealed that the mesothelium of the mouse allantois exhibits distinct regional properties. By headfold stages (~7.75–8.0 dpc), distal mesothelium was generally squamous in shape, and highly permeable to BDA challenge, whereas ventral proximal mesothelium, referred to as “ventral cuboidal mesothelium” (VCM) for the characteristic cuboidal shape of its cells, was relatively impermeable. Although “dorsal cuboidal mesothelium” (DCM) resembled the VCM in cell shape, its permeability to BDA was intermediate between the other two regions. Results of immunostaining for Zonula Occludens-1 (ZO-1) and Epithelial-cadherin (E-cadherin), together with transmission electron microscopy (TEM), suggested that impermeability in the VCM may be due to greater cellular contact area between cells and close packing rather than to maturity of tight junctions, the latter of which, by comparison with the visceral yolk sac, appeared to be rare or absent from the allantoic surface. Both VCM and DCM exhibited an ultrastructure more favorable for protein synthesis than did the distal squamous mesothelium; however, at most stages, VCM exhibited robust afadin (AF-6), whereas the DCM uniquely contained alpha-4-integrin. These observations demonstrate that the allantoic mesothelium is not a conventional epithelium but possesses regional ultrastructural, functional and molecular differences that may play important roles in the correct deployment of the umbilical cord and its associated vascular, hematopoietic, and other cell types. PMID:21284019

US Navy Women's Experience of an Abnormal Cervical Cancer Screening.

PubMed

Braun, Lisa A; Kennedy, Holly Powell; Sadler, Lois S; Dixon, Jane; Womack, Julie; Wilson, Candy

2016-01-01

Recent policy revisions allow greater inclusion of military women in operational and/or deployable positions (ie, shipboard, overseas, and war zone duty assignments), but these positions can create unique health care challenges. Military members are often transient due to deployments and change of duty stations, impacting timely follow-up care for treatable health conditions. There has been minimal research on challenges or strategies in preventive health screening and follow-up for US military women. The purpose of this qualitative research study was to describe US Navy women's experiences with abnormal cervical cancer screenings requiring colposcopic follow-up care. Ship- and shored-based women receiving care at a military colposcopy clinic completed interviews about their experience. Two forms of narrative analysis, Labov's sociolinguistic structural analysis and Braun and Clarke's thematic analysis, were employed to gain a more robust understanding of the women's experiences. The sample was comprised of 26 women (16 ship-based, 10 shore-based). Five themes were identified: 1) It's like this bombshell (initial abnormal results notification); 2) I didn't understand (self-discovery process); 3) Freaked (emotional toll); 4) It's kind of like this back and forth (scheduling and navigating care); and 5) It really opened my eyes (lessons learned). The women's stories highlighted some issues unique to military health care, such as operational demands and follow-up care; other issues are likely common for most women learning about an abnormal cervical cancer screening result. Areas important for practice and future research include improving notification practices, providing information, understanding women's fear, and continuity of care. Research exploring educational initiatives and self-management practices are critical within military populations. © 2016 by the American College of Nurse-Midwives.

Advantages and Challenges of Relaxor-PbTiO3 Ferroelectric Crystals for Electroacoustic Transducers- A Review

PubMed Central

Zhang, Shujun; Li, Fei; Jiang, Xiaoning; Kim, Jinwook; Luo, Jun; Geng, Xuecang

2014-01-01

Relaxor-PbTiO3 (PT) based ferroelectric crystals with the perovskite structure have been investigated over the last few decades due to their ultrahigh piezoelectric coefficients (d33 > 1500 pC/N) and electromechanical coupling factors (k33 > 90%), far outperforming state-of-the-art ferroelectric polycrystalline Pb(Zr,Ti)O3 ceramics, and are at the forefront of advanced electroacoustic applications. In this review, the performance merits of relaxor-PT crystals in various electroacoustic devices are presented from a piezoelectric material viewpoint. Opportunities come from not only the ultrahigh properties, specifically coupling and piezoelectric coefficients, but through novel vibration modes and crystallographic/domain engineering. Figure of merits (FOMs) of crystals with various compositions and phases were established for various applications, including medical ultrasonic transducers, underwater transducers, acoustic sensors and tweezers. For each device application, recent developments in relaxor-PT ferroelectric crystals were surveyed and compared with state-of-the-art polycrystalline piezoelectrics, with an emphasis on their strong anisotropic features and crystallographic uniqueness, including engineered domain - property relationships. This review starts with an introduction on electroacoustic transducers and the history of piezoelectric materials. The development of the high performance relaxor-PT single crystals, with a focus on their uniqueness in transducer applications, is then discussed. In the third part, various FOMs of piezoelectric materials for a wide range of ultrasound applications, including diagnostic ultrasound, therapeutic ultrasound, underwater acoustic and passive sensors, tactile sensors and acoustic tweezers, are evaluated to provide a thorough understanding of the materials’ behavior under operational conditions. Structure-property-performance relationships are then established. Finally, the impacts and challenges of relaxor-PT crystals are summarized to guide on-going and future research in the development of relaxor-PT crystals for the next generation electroacoustic transducers. PMID:25530641

Reliable retrieval of atmospheric and aquatic parameters in coastal and inland environments from polar-orbiting and geostationary platforms: challenges and opportunities

NASA Astrophysics Data System (ADS)

Stamnes, Knut; Li, Wei; Lin, Zhenyi; Fan, Yongzhen; Chen, Nan; Gatebe, Charles; Ahn, Jae-Hyun; Kim, Wonkook; Stamnes, Jakob J.

2017-04-01

Simultaneous retrieval of aerosol and surface properties by means of inverse techniques based on a coupled atmosphere-surface radiative transfer model, neural networks, and optimal estimation can yield considerable improvements in retrieval accuracy in complex aquatic environments compared with traditional methods. Remote sensing of such environments represent specific challenges due (i) the complexity of the atmosphere and water inherent optical properties, (ii) unique bidirectional dependencies of the water-leaving radiance, and (iii) the desire to do retrievals for large solar zenith and viewing angles. We will discuss (a) how challenges related to atmospheric gaseous absorption, absorbing aerosols, and turbid waters can be addressed by using a coupled atmosphere-surface radiative transfer (forward) model in the retrieval process, (b) how the need to correct for bidirectional effects can be accommodated in a systematic and reliable manner, (c) how polarization information can be utilized, (d) how the curvature of the atmosphere can be taken into account, and (e) how neural networks and optimal estimation can be used to obtain fast yet accurate retrievals. Special emphasis will be placed on how information from existing and future sensors deployed on polar-orbiting and geostationary platforms can be obtained in a reliable and accurate manner. The need to provide uncertainty assessments and error budgets will also be discussed.

Challenges and solutions in medically managed ACS in the Asia-Pacific region: expert recommendations from the Asia-Pacific ACS Medical Management Working Group.

PubMed

Huo, Yong; Thompson, Peter; Buddhari, Wacin; Ge, Junbo; Harding, Scott; Ramanathan, Letchuman; Reyes, Eugenio; Santoso, Anwar; Tam, Li-Wah; Vijayaraghavan, Govindan; Yeh, Hung-I

2015-03-15

Acute coronary syndromes (ACS) remain a leading cause of mortality and morbidity in the Asia-Pacific (APAC) region. International guidelines advocate invasive procedures in all but low-risk ACS patients; however, a high proportion of ACS patients in the APAC region receive solely medical management due to a combination of unique geographical, socioeconomic, and population-specific barriers. The APAC ACS Medical Management Working Group recently convened to discuss the ACS medical management landscape in the APAC region. Local and international ACS guidelines and the global and APAC clinical evidence-base for medical management of ACS were reviewed. Challenges in the provision of optimal care for these patients were identified and broadly categorized into issues related to (1) accessibility/systems of care, (2) risk stratification, (3) education, (4) optimization of pharmacotherapy, and (5) cost/affordability. While ACS guidelines clearly represent a valuable standard of care, the group concluded that these challenges can be best met by establishing cardiac networks and individual hospital models/clinical pathways taking into account local risk factors (including socioeconomic status), affordability and availability of pharmacotherapies/invasive facilities, and the nature of local healthcare systems. Potential solutions central to the optimization of ACS medical management in the APAC region are outlined with specific recommendations. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Africa has unique and urgent barriers to cleft care: lessons from practitioners at the Pan-African Congress on Cleft Lip and Palate.

PubMed

Adetayo, Oluwaseun; Ford, Rachel; Martin, Mark

2012-01-01

The goals of this study were to delineate the protocols employed for managing patients with cleft lip and palate deformities, delineate the challenges facing practitioners and patients, and to determine the patient and physician barriers to cleft care delivery in the region. Survey questionnaires were administered to practitioners attending the second Pan-African Congress on Cleft Lip and Palate (PACCLIP), which took place in Ibadan, Nigeria, West Africa from February 4-7, 2007. The conference included 225 participants, representing 17 African countries Protocols for repair of cleft lip and palate deformities were varied, with Millard's and von Langenbeck's techniques being the preferred approach for the management of cleft lip and palate deformities, respectively. A large proportion of providers have limited access to core cleft care supporting teams, especially speech language pathologists, orthodontists, and audiologists. Several challenging barriers to cleft care were also identified at both the institutional and individual levels and are reported. Geographic separation in Africa presents a similar challenge due to isolationism as it does to surgeons in Europe. Specific to Africa are the increased barriers to care, and economic and financial hardship at various levels. A focus on funding, team building, infrastructural support, and patient education appear to be crucial in improving the care and lives of children with facial clefts in Africa.

Challenges in fitting a hearing aid to a severely collapsed ear canal and mixed hearing loss.

PubMed

Oeding, Kristi; Valente, Michael; Chole, Richard

2012-04-01

Collapsed ear canals typically occur when an outside force, such as a headset for audiometric testing, is present. However, when a collapsed ear canal occurs without external pressure, this creates a challenge not only for performing audiometric testing but also for coupling a hearing aid to the ear canal. This case report highlights the challenges associated with fitting a hearing aid on a patient with a severe anterior-posterior collapsed ear canal with a mixed hearing loss. A 67-yr-old female originally presented to Washington University in St. Louis School of Medicine in 1996 with a long-standing history of bilateral otosclerosis. She had chronic ear infections in the right ear and a severely collapsed ear canal in the left ear and was fit with a bone anchored hearing aid (BAHA®) on the right side in 2003. However, benefit from the BAHA started to decrease due to changes in hearing, and a different hearing solution was needed. It was proposed that a hearing aid be fit to her collapsed left ear canal; however, trying to couple a hearing aid to the collapsed ear canal required unique noncustom earmold solutions. This case study highlights some of the obstacles and potential solutions for coupling a hearing aid to a severely collapsed ear canal. American Academy of Audiology.

Addressing China’s grand challenge of achieving food security while ensuring environmental sustainability

PubMed Central

Lu, Yonglong; Jenkins, Alan; Ferrier, Robert C.; Bailey, Mark; Gordon, Iain J.; Song, Shuai; Huang, Jikun; Jia, Shaofeng; Zhang, Fusuo; Liu, Xuejun; Feng, Zhaozhong; Zhang, Zhibin

2015-01-01

China’s increasingly urbanized and wealthy population is driving a growing and changing demand for food, which might not be met without significant increase in agricultural productivity and sustainable use of natural resources. Given the past relationship between lack of access to affordable food and political instability, food security has to be given a high priority on national political agendas in the context of globalization. The drive for increased food production has had a significant impact on the environment, and the deterioration in ecosystem quality due to historic and current levels of pollution will potentially compromise the food production system in China. We discuss the grand challenges of not only producing more food but also producing it sustainably and without environmental degradation. In addressing these challenges, food production should be considered as part of an environmental system (soil, air, water, and biodiversity) and not independent from it. It is imperative that new ways of meeting the demand for food are developed while safeguarding the natural resources upon which food production is based. We present a holistic approach to both science and policy to ensure future food security while embracing the ambition of achieving environmental sustainability in China. It is a unique opportunity for China to be a role model as a new global player, especially for other emerging economies. PMID:26601127

Laser Remediation of Threats Posed by Small Orbital Debris

NASA Technical Reports Server (NTRS)

Fork, Richard L.; Rogers, Jan R.; Hovater, Mary A.

2012-01-01

The continually increasing amount of orbital debris in near Earth space poses an increasing challenge to space situational awareness. Recent collisions of spacecraft caused abrupt increases in the density of both large and small debris in near Earth space. An especially challenging class of threats is that due to the increasing density of small (1 mm to 10 cm dimension) orbital debris. This small debris poses a serious threat since: (1) The high velocity enables even millimeter dimension debris to cause serious damage to vulnerable areas of space assets, e.g., detector windows; (2) The small size and large number of debris elements prevent adequate detection and cataloguing. We have identified solutions to this threat in the form of novel laser systems and novel ways of using these laser systems. While implementation of the solutions we identify is challenging we find approaches offering threat mitigation within time frames and at costs of practical interest. We base our analysis on the unique combination of coherent light specifically structured in both space and time and applied in novel ways entirely within the vacuum of space to deorbiting small debris. We compare and contrast laser based small debris removal strategies using ground based laser systems with strategies using space based laser systems. We find laser systems located and used entirely within space offer essential and decisive advantages over groundbased laser systems.

Continuous-flow mass production of silicon nanowires via substrate-enhanced metal-catalyzed electroless etching of silicon with dissolved oxygen as an oxidant.

PubMed

Hu, Ya; Peng, Kui-Qing; Liu, Lin; Qiao, Zhen; Huang, Xing; Wu, Xiao-Ling; Meng, Xiang-Min; Lee, Shuit-Tong

2014-01-13

Silicon nanowires (SiNWs) are attracting growing interest due to their unique properties and promising applications in photovoltaic devices, thermoelectric devices, lithium-ion batteries, and biotechnology. Low-cost mass production of SiNWs is essential for SiNWs-based nanotechnology commercialization. However, economic, controlled large-scale production of SiNWs remains challenging and rarely attainable. Here, we demonstrate a facile strategy capable of low-cost, continuous-flow mass production of SiNWs on an industrial scale. The strategy relies on substrate-enhanced metal-catalyzed electroless etching (MCEE) of silicon using dissolved oxygen in aqueous hydrofluoric acid (HF) solution as an oxidant. The distinct advantages of this novel MCEE approach, such as simplicity, scalability and flexibility, make it an attractive alternative to conventional MCEE methods.

Applications of Fluorogens with Rotor Structures in Solar Cells.

PubMed

Ong, Kok-Haw; Liu, Bin

2017-05-29

Solar cells are devices that convert light energy into electricity. To drive greater adoption of solar cell technologies, higher cell efficiencies and reductions in manufacturing cost are necessary. Fluorogens containing rotor structures may be helpful in addressing some of these challenges due to their unique twisted structures and photophysics. In this review, we discuss the applications of rotor-containing molecules as dyes for luminescent down-shifting layers and luminescent solar concentrators, where their aggregation-induced emission properties and large Stokes shifts are highly desirable. We also discuss the applications of molecules containing rotors in third-generation solar cell technologies, namely dye-sensitized solar cells and organic photovoltaics, where the twisted 3-dimensional rotor structures are used primarily for aggregation control. Finally, we discuss perspectives on the future role of molecules containing rotor structures in solar cell technologies.

An improved interim therapeutic restoration technique for management of anterior early childhood caries: report of two cases.

PubMed

Nelson, Travis

2013-01-01

Early childhood caries presents unique treatment challenges that often require advanced behavior management techniques, such as general anesthesia or procedural sedation. In some cases, use of these pharmacologic adjuncts is undesirable or not possible. The interim therapeutic restoration is a treatment method that, while sometimes employed in such cases, can often produce unsatisfactory results in primary anterior teeth. This is often due to insufficient bulk of material and lack of retention. The purpose of this report was to describe a simple alternative technique (resin modified glass ionomer strip crowns) that may be employed to deliver esthetic anterior restorations to marginally cooperative children in the dental clinic setting and to report on two cases in which it was successfully used. \\\\\\Department of Pediatric Dentistry, University of Washington, Seattle, Wash., USA. tmnelson@uw.edu

Characterizing intestinal strictures with acoustic resolution photoacoustic microscopy

NASA Astrophysics Data System (ADS)

Lei, Hao; Xu, Guan; Liu, Shengchun; Johnson, Laura A.; Moons, David S.; Higgins, Peter D. R.; Rice, Michael D.; Ni, Jun; Wang, Xueding

2016-03-01

Crohn's disease (CD) is an autoimmune disease, which may cause obstructing intestinal strictures due to inflammation, fibrosis (deposition of collagen), or a combination of both. Identifying the different stages of the disease progression is still challenging. In this work, we indicated the feasibility of non-invasively characterizing intestinal strictures using photoacoustic imaging (PAI), utilizing the uniquely optical absorption of hemoglobin and collagen. Surgically removed human intestinal stricture specimens were investigated with a prototype PAI system. 2D PA images with acoustic resolution at wavelength 532, 1210 and 1310 nm were formulated, and furthermore, the PA histochemical components images which show the microscopic distributions of histochemical components were solved. Imaging experiments on surgically removed human intestinal specimens has demonstrated the solved PA images were significantly different associated with the presence of fibrosis, which could be applied to characterize the intestinal strictures for given specimens.

Using Model Replication to Improve the Reliability of Agent-Based Models

NASA Astrophysics Data System (ADS)

Zhong, Wei; Kim, Yushim

The basic presupposition of model replication activities for a computational model such as an agent-based model (ABM) is that, as a robust and reliable tool, it must be replicable in other computing settings. This assumption has recently gained attention in the community of artificial society and simulation due to the challenges of model verification and validation. Illustrating the replication of an ABM representing fraudulent behavior in a public service delivery system originally developed in the Java-based MASON toolkit for NetLogo by a different author, this paper exemplifies how model replication exercises provide unique opportunities for model verification and validation process. At the same time, it helps accumulate best practices and patterns of model replication and contributes to the agenda of developing a standard methodological protocol for agent-based social simulation.

Facility design consideration for continuous mix production of class 1.3 propellant

NASA Technical Reports Server (NTRS)

Williamson, K. L.; Schirk, P. G.

1994-01-01

In November of 1989, NASA awarded the Advanced Solid Rocket Motor (ASRM) contract to Lockheed Missiles and Space Company (LMSC) for production of advanced solid rocket motors using the continuous mix process. Aerojet ASRM division (AAD) was selected as the facility operator and RUST International Corporation provided the engineering, procurement, and construction management services. The continuous mix process mandates that the mix and cast facilities be 'close-coupled' along with the premix facilities, creating unique and challenging requirements for the facility designer. The classical approach to handling energetic materials-division into manageable quantities, segregation, and isolation-was not available due to these process requirements and quantities involved. This paper provides a description of the physical facilities, the continuous mix process, and discusses the monitoring and detection techniques used to mitigate hazards and prevent an incident.

Nanomaterials as analytical tools for genosensors.

PubMed

Abu-Salah, Khalid M; Alrokyan, Salman A; Khan, Muhammad Naziruddin; Ansari, Anees Ahmad

2010-01-01

Nanomaterials are being increasingly used for the development of electrochemical DNA biosensors, due to the unique electrocatalytic properties found in nanoscale materials. They offer excellent prospects for interfacing biological recognition events with electronic signal transduction and for designing a new generation of bioelectronic devices exhibiting novel functions. In particular, nanomaterials such as noble metal nanoparticles (Au, Pt), carbon nanotubes (CNTs), magnetic nanoparticles, quantum dots and metal oxide nanoparticles have been actively investigated for their applications in DNA biosensors, which have become a new interdisciplinary frontier between biological detection and material science. In this article, we address some of the main advances in this field over the past few years, discussing the issues and challenges with the aim of stimulating a broader interest in developing nanomaterial-based biosensors and improving their applications in disease diagnosis and food safety examination.

Recent Progress for the Effective Prevention and Treatment of Recurrent Clostridium difficile Infection.

PubMed

Ramsay, Isobel; Brown, Nicholas M; Enoch, David A

2018-01-01

Recurrence occurs in approximately 25% of all cases of Clostridium difficile infection (CDI) and poses a unique clinical challenge. Traditionally, treatment options of CDI have been limited to regimes of established antibiotics (eg, pulsed/tapered vancomycin) but faecal transplantation is emerging as a useful alternative. In recent years, promising new strategies have emerged for effective prevention of recurrent CDI (rCDI) including new antimicrobials (eg, fidaxomicin) and monoclonal antibodies (eg, bezlotoxumab). Despite promising progress in this area, obstacles remain for making the best use of these resources due to uncertainty over patient selection. This commentary describes the current epidemiology of rCDI, its clinical impact and risk factors, some of the measures used for treating and preventing rCDI, and some of the emerging treatment options. It then describes some of the obstacles that need to be overcome.

Automated On-tip Affinity Capture Coupled with Mass Spectrometry to Characterize Intact Antibody-Drug Conjugates from Blood

NASA Astrophysics Data System (ADS)

Li, Ke Sherry; Chu, Phillip Y.; Fourie-O'Donohue, Aimee; Srikumar, Neha; Kozak, Katherine R.; Liu, Yichin; Tran, John C.

2018-05-01

Antibody-drug conjugates (ADCs) present unique challenges for ligand-binding assays primarily due to the dynamic changes of the drug-to-antibody ratio (DAR) distribution in vivo and in vitro. Here, an automated on-tip affinity capture platform with subsequent mass spectrometry analysis was developed to accurately characterize the DAR distribution of ADCs from biological matrices. A variety of elution buffers were tested to offer optimal recovery, with trastuzumab serving as a surrogate to the ADCs. High assay repeatability (CV 3%) was achieved for trastuzumab antibody when captured below the maximal binding capacity of 7.5 μg. Efficient on-tip deglycosylation was also demonstrated in 1 h followed by affinity capture. Moreover, this tip-based platform affords higher throughput for DAR characterization when compared with a well-characterized bead-based method.

A Full-Time Nurse for Every School: A Call to Action to Make It Happen.

PubMed

Nikpour, Jacqueline; Hassmiller, Susan

2017-09-01

In June 2016, the American Academy of Pediatrics released its new policy statement recommending a full-time registered nurse in every school building. Indeed, increasing attention is being focused on school nursing, in part due to recent legislation, including the Affordable Care Act, the Healthy Hunger-Free Kids Act, and the Every Student Succeeds Act. Advocating for nursing practice within an education setting presents unique challenges in terms of changing the common perception of school nurses, variances in funding streams for school nursing, and the ability to link health outcomes with educational outcomes. The purpose of this article is to discuss the rationale for a school nurse in every building along with presenting action steps that individual and groups of school nurses can utilize to advocate for a full-time registered nurse in every school.

Methods for Discerning Cloud Reflectivity Changes due to the Indirect Effect of Aerosol: A Pilot-study for Triana

NASA Technical Reports Server (NTRS)

Kinne, S.; Wiscombe, Warren; Einaudi, Franco (Technical Monitor)

2001-01-01

Understanding the effect of aerosol on cloud systems is one of the major challenges in atmospheric and climate research. Local studies suggest a multitude of influences on cloud properties. Yet the overall effect on cloud albedo, a critical parameter in climate simulations, remains uncertain. NASA's Triana mission will provide, from its EPIC multi-spectral imager, simultaneous data on aerosol properties and cloud reflectivity. With Triana's unique position in space these data will be available not only globally but also over the entire daytime, well suited to accommodate the often short lifetimes of aerosol and investigations around diurnal cycles. This pilot study explores the ability to detect relationships between aerosol properties and cloud reflectivity with sophisticated statistical methods. Sample results using data from the EOS Terra platform to simulate Triana are presented.

Geriatric Oral Health: A Review Article

PubMed Central

Razak, P Abdul; Richard, K M Jose; Thankachan, Rekha P; Hafiz, K A Abdul; Kumar, K Nanda; Sameer, K M

2014-01-01

Oral health is not separate from general health, but maintaining oral health is definitely difficult and different in old age. Even though, few elderly have physical and/or mental situation that call for particular interest in the dental workplace, one should not presume that all elderly community shares these circumstances. In order to achieve health, it is necessary to know few aspects of old age. In due course of old age body tissues get harder, collection of waste products in body cells and loss of lubrication leads to impaired functions of various organs. The design and implementation of comprehensive preventive dentistry protocols for elders presents the dental profession with many challenges. Although a specific protocol must be tailored to meet the unique needs of the individual patient, there are certain factors common to elderly segment of the population that may influence these protocols. PMID:25628498

Nanomaterials as Analytical Tools for Genosensors

PubMed Central

Abu-Salah, Khalid M.; Alrokyan, Salman A.; Khan, Muhammad Naziruddin; Ansari, Anees Ahmad

2010-01-01

Nanomaterials are being increasingly used for the development of electrochemical DNA biosensors, due to the unique electrocatalytic properties found in nanoscale materials. They offer excellent prospects for interfacing biological recognition events with electronic signal transduction and for designing a new generation of bioelectronic devices exhibiting novel functions. In particular, nanomaterials such as noble metal nanoparticles (Au, Pt), carbon nanotubes (CNTs), magnetic nanoparticles, quantum dots and metal oxide nanoparticles have been actively investigated for their applications in DNA biosensors, which have become a new interdisciplinary frontier between biological detection and material science. In this article, we address some of the main advances in this field over the past few years, discussing the issues and challenges with the aim of stimulating a broader interest in developing nanomaterial-based biosensors and improving their applications in disease diagnosis and food safety examination. PMID:22315580

Polymer and ceramic nanocomposites for aerospace applications

NASA Astrophysics Data System (ADS)

Rathod, Vivek T.; Kumar, Jayanth S.; Jain, Anjana

2017-11-01

This paper reviews the potential of polymer and ceramic matrix composites for aerospace/space vehicle applications. Special, unique and multifunctional properties arising due to the dispersion of nanoparticles in ceramic and metal matrix are briefly discussed followed by a classification of resulting aerospace applications. The paper presents polymer matrix composites comprising majority of aerospace applications in structures, coating, tribology, structural health monitoring, electromagnetic shielding and shape memory applications. The capabilities of the ceramic matrix nanocomposites to providing the electromagnetic shielding for aircrafts and better tribological properties to suit space environments are discussed. Structural health monitoring capability of ceramic matrix nanocomposite is also discussed. The properties of resulting nanocomposite material with its disadvantages like cost and processing difficulties are discussed. The paper concludes after the discussion of the possible future perspectives and challenges in implementation and further development of polymer and ceramic nanocomposite materials.

Surveillance in a Telemedicine Setting: Application of Epidemiologic Methods at NASA Johnson Space Center Adriana

NASA Technical Reports Server (NTRS)

Babiak-Vazquez, Adriana; Ruffaner, Lanie; Wear, Mary; Crucian Brian; Sams, Clarence; Lee, Lesley R.; Van Baalen, Mary

2016-01-01

Space medicine presents unique challenges and opportunities for epidemiologists, such as the use of telemedicine during spaceflight. Medical capabilities aboard the International Space Station (ISS) are limited due to severe restrictions on power, volume, and mass. Consequently, inflight health information is based heavily on crewmember (CM) self-report of signs and symptoms, rather than formal diagnoses. While CM's are in flight, the primary source of crew health information is verbal communication between physicians and crewmembers. In 2010 NASA implemented the Lifetime Surveillance of Astronaut Health, an occupational surveillance program for the U.S. Astronaut corps. This has shifted the epidemiological paradigm from tracking diagnoses based on traditional terrestrial clinical practice to one that incorporates symptomatology and may gain a more population-based understanding of early detection of disease process.

Electrochemical biosensors for hormone analyses.

PubMed

Bahadır, Elif Burcu; Sezgintürk, Mustafa Kemal

2015-06-15

Electrochemical biosensors have a unique place in determination of hormones due to simplicity, sensitivity, portability and ease of operation. Unlike chromatographic techniques, electrochemical techniques used do not require pre-treatment. Electrochemical biosensors are based on amperometric, potentiometric, impedimetric, and conductometric principle. Amperometric technique is a commonly used one. Although electrochemical biosensors offer a great selectivity and sensitivity for early clinical analysis, the poor reproducible results, difficult regeneration steps remain primary challenges to the commercialization of these biosensors. This review summarizes electrochemical (amperometric, potentiometric, impedimetric and conductometric) biosensors for hormone detection for the first time in the literature. After a brief description of the hormones, the immobilization steps and analytical performance of these biosensors are summarized. Linear ranges, LODs, reproducibilities, regenerations of developed biosensors are compared. Future outlooks in this area are also discussed. Copyright © 2014 Elsevier B.V. All rights reserved.

Porous plug for Gravity Probe B

NASA Astrophysics Data System (ADS)

Wang, Suwen; Everitt, C. W. Francis; Frank, David J.; Lipa, John A.; Muhlfelder, Barry F.

2015-11-01

The confinement of superfluid helium for a Dewar in space poses a unique challenge due to its propensity to minimize thermal gradients by essentially viscous-free counterflow. This poses the risk of losing liquid through a vent pipe, reducing the efficiency of the cooling process. To confine the liquid helium in the Gravity Probe B (GP-B) flight Dewar, a porous plug technique was invented at Stanford University. Here, we review the history of the porous plug and its development, and describe the physics underlying its operation. We summarize a few missions that employed porous plugs, some of which preceded the launch of GP-B. The design, manufacture and flight performance of the GP-B plug are described, and its use resulted in the successful operation of the 2441 l flight Dewar on-orbit for 17.3 months.

[Current insights about recurrence of glomerular diseases after renal transplantation].

PubMed

Kofman, Tomek; Oniszczuk, Julie; Lang, Philippe; Grimbert, Philippe; Audard, Vincent

2018-05-01

Recurrence of glomerular disease after renal transplantation is a frequent cause of graft loss. Incidence, risk factors and outcome of recurrence are widely due to the underlying glomerular disease. Graft biopsy analysis is required to confirm the definitive diagnosis of recurrence and to start an appropriate therapy that, in some cases, remains challenging to prevent graft failure. Increased use of protocol biopsy and recent advances in our understanding of the pathogenesis of some glomerular diseases with the identification of some relevant biomarkers provide a unique opportunity to initiate kidney-protective therapy at early stages of recurrence on the graft. This review summarizes our current knowledge on the management of many recurrent primary and secondary glomerulonephritis after kidney transplantation. Copyright © 2018 Société francophone de néphrologie, dialyse et transplantation. Published by Elsevier Masson SAS. All rights reserved.

Neurogaming Technology Meets Neuroscience Education: A Cost-Effective, Scalable, and Highly Portable Undergraduate Teaching Laboratory for Neuroscience

PubMed Central

de Wit, Bianca; Badcock, Nicholas A.; Grootswagers, Tijl; Hardwick, Katherine; Teichmann, Lina; Wehrman, Jordan; Williams, Mark; Kaplan, David Michael

2017-01-01

Active research-driven approaches that successfully incorporate new technology are known to catalyze student learning. Yet achieving these objectives in neuroscience education is especially challenging due to the prohibitive costs and technical demands of research-grade equipment. Here we describe a method that circumvents these factors by leveraging consumer EEG-based neurogaming technology to create an affordable, scalable, and highly portable teaching laboratory for undergraduate courses in neuroscience. This laboratory is designed to give students hands-on research experience, consolidate their understanding of key neuroscience concepts, and provide a unique real-time window into the working brain. Survey results demonstrate that students found the lab sessions engaging. Students also reported the labs enhanced their knowledge about EEG, their course material, and neuroscience research in general. PMID:28690430

Global impacts of U.S. bioenergy production and policy: A general equilibrium perspective

NASA Astrophysics Data System (ADS)

Evans, Samuel Garner

The conversion of biomass to energy represents a promising pathway forward in efforts to reduce fossil fuel use in the transportation and electricity sectors. In addition to potential benefits, such as greenhouse gas reductions and increased energy security, bioenergy production also presents a unique set of challenges. These challenges include tradeoffs between food and fuel production, distortions in energy markets, and terrestrial emissions associated with changing land-use patterns. Each of these challenges arises from market-mediated responses to bioenergy production, and are therefore largely economic in nature. This dissertation directly addresses these opportunities and challenges by evaluating the economic impacts of U.S. bioenergy production and policy, focusing on both existing and future biomass-to-energy pathways. The analysis approaches the issue from a global, economy-wide perspective, reflecting two important facts. First, that large-scale bioenergy production connects multiple sectors of the economy due to the use of agricultural land resources for biomass production, and competition with fossil fuels in energy markets. Second, markets for both agricultural and energy commodities are highly integrated globally, causing domestic policies to have international effects. The reader can think of this work as being comprised of three parts. Part I provides context through an extensive review of the literature on the market-mediated effects of conventional biofuel production (Chapter 2) and develops a general equilibrium modeling framework for assessing the extent to which these phenomenon present a challenge for future bioenergy pathways (Chapter 3). Part II (Chapter 4) explores the economic impacts of the lignocellulosic biofuel production targets set in the U.S. Renewable Fuel Standard on global agricultural and energy commodity markets. Part III (Chapter 5) extends the analysis to consider potential inefficiencies associated with policy-induced competition for biomass between the electricity and transportation fuel sectors.

Microscale Characterization of the Viscoelastic Properties of Hydrogel Biomaterials using Dual-Mode Ultrasound Elastography

PubMed Central

Hong, Xiaowei; Stegemann, Jan P.; Deng, Cheri X.

2016-01-01

Characterization of the microscale mechanical properties of biomaterials is a key challenge in the field of mechanobiology. Dual-mode ultrasound elastography (DUE) uses high frequency focused ultrasound to induce compression in a sample, combined with interleaved ultrasound imaging to measure the resulting deformation. This technique can be used to non-invasively perform creep testing on hydrogel biomaterials to characterize their viscoelastic properties. DUE was applied to a range of hydrogel constructs consisting of either hydroxyapatite (HA)-doped agarose, HA-collagen, HA-fibrin, or preosteoblast-seeded collagen constructs. DUE provided spatial and temporal mapping of local and bulk displacements and strains at high resolution. Hydrogel materials exhibited characteristic creep behavior, and the maximum strain and residual strain were both material- and concentration-dependent. Burger’s viscoelastic model was used to extract characteristic parameters describing material behavior. Increased protein concentration resulted in greater stiffness and viscosity, but did not affect the viscoelastic time constant of acellular constructs. Collagen constructs exhibited significantly higher modulus and viscosity than fibrin constructs. Cell-seeded collagen constructs became stiffer with altered mechanical behavior as they developed over time. Importantly, DUE also provides insight into the spatial variation of viscoelastic properties at sub-millimeter resolution, allowing interrogation of the interior of constructs. DUE presents a novel technique for non-invasively characterizing hydrogel materials at the microscale, and therefore may have unique utility in the study of mechanobiology and the characterization of hydrogel biomaterials. PMID:26928595

Microscale characterization of the viscoelastic properties of hydrogel biomaterials using dual-mode ultrasound elastography.

PubMed

Hong, Xiaowei; Stegemann, Jan P; Deng, Cheri X

2016-05-01

Characterization of the microscale mechanical properties of biomaterials is a key challenge in the field of mechanobiology. Dual-mode ultrasound elastography (DUE) uses high frequency focused ultrasound to induce compression in a sample, combined with interleaved ultrasound imaging to measure the resulting deformation. This technique can be used to non-invasively perform creep testing on hydrogel biomaterials to characterize their viscoelastic properties. DUE was applied to a range of hydrogel constructs consisting of either hydroxyapatite (HA)-doped agarose, HA-collagen, HA-fibrin, or preosteoblast-seeded collagen constructs. DUE provided spatial and temporal mapping of local and bulk displacements and strains at high resolution. Hydrogel materials exhibited characteristic creep behavior, and the maximum strain and residual strain were both material- and concentration-dependent. Burger's viscoelastic model was used to extract characteristic parameters describing material behavior. Increased protein concentration resulted in greater stiffness and viscosity, but did not affect the viscoelastic time constant of acellular constructs. Collagen constructs exhibited significantly higher modulus and viscosity than fibrin constructs. Cell-seeded collagen constructs became stiffer with altered mechanical behavior as they developed over time. Importantly, DUE also provides insight into the spatial variation of viscoelastic properties at sub-millimeter resolution, allowing interrogation of the interior of constructs. DUE presents a novel technique for non-invasively characterizing hydrogel materials at the microscale, and therefore may have unique utility in the study of mechanobiology and the characterization of hydrogel biomaterials. Copyright © 2016 Elsevier Ltd. All rights reserved.

Big Events and Risks to Global Substance Using Populations: Unique Threats and Common Challenges.

PubMed

Mackey, Tim K; Strathdee, Steffanie A

2015-01-01

In this commentary, we review a set of "Big Events" from around the world that have adversely impacted substance using populations by first identifying common thematic areas between them, and then describing the unique challenges faced by the diverse and vulnerable populations impacted. The Big Events reviewed are multifaceted and complex in nature, and include the recent global financial crisis, economic and trade sanctions, political transition and its impact on ethnic minorities, colonialism and indigenous communities, and ecological disasters. All have led to immense trauma, displacement, and disruption to critical healthcare services/treatment for people who use drugs, populations who are left underserved in the midst of these crises. It is our hope that through this comparative assessment, global policymakers will proactively identify Big Events and prioritize the development of interventions and policy that meet the unique and immediate needs of substance using population in order to mitigate the significant negative short- and long-term impacts on global public health.

Mucosal melanoma: a clinically and biologically unique disease entity.

PubMed

Carvajal, Richard D; Spencer, Sharon A; Lydiatt, William

2012-03-01

Mucosal melanoma (MM) is an aggressive and clinically complex malignancy made more challenging by its relative rarity. Because of the rarity of MM as a whole, and because of the unique biology and clinical challenges of MM arising from each anatomic location, understanding of this disease and its optimal management remains limited. The impact of various treatment strategies on disease control and survival has been difficult to assess because of the small size of most reported series of MM arising from any one particular site, the retrospective nature of most series, and the lack of a uniform comprehensive staging system for this disease. This article summarizes the clinical, pathologic, and molecular features, and the diagnostic and therapeutic considerations for the management of MM, underscoring the similarities and differences from cutaneous melanoma. Furthermore, the distinct clinical features and management implications unique to melanoma arising from the mucosal surfaces of the head and neck, the anorectal region, and the female genital tract are highlighted.

Ni-Ti Alloys for Aerospace Bearing Applications

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher

2017-01-01

Nickel-rich Ni-Ti alloys are emerging candidate materials for aerospace bearing applications. These alloys exhibit a unique combination of physical, chemical, and tribological properties that are highly relevant to challenging aerospace bearings and other mechanical components. Despite being made solely from metals, Ni-Ti alloys are classified as intermetallics with properties akin to both metals and ceramics. For instance, like metals, they are electrically conductive but they tend to be brittle like ceramics. When properly processed, they have high hardness, low elastic modulus and an extensive elastic deformation range that imparts extraordinarily high resilience and resistance to denting. New alloy compositions enable simpler thermal processing and machining and intensive microstructural analyses have helped elucidate the materials science mechanisms governing hardness. In this paper, the application of state-of-art in NiTi alloys for aerospace bearings and mechanical components is explored. In addition to reviewing future trends and remaining challenges, the unique approaches and methods of tailoring bearing design to accommodate NiTis unique properties is discussed.

Cold-water coral carbonate mounds as unique palaeo-archives: the Plio-Pleistocene Challenger Mound record (NE Atlantic)

NASA Astrophysics Data System (ADS)

Thierens, M.; Browning, E.; Pirlet, H.; Loutre, M.-F.; Dorschel, B.; Huvenne, V. A. I.; Titschack, J.; Colin, C.; Foubert, A.; Wheeler, A. J.

2013-08-01

Through the interplay of a stabilising cold-water coral framework and a dynamic sedimentary environment, cold-water coral carbonate mounds create distinctive centres of bio-geological accumulation in often complex (continental margin) settings. The IODP Expedition 307 drilling of the Challenger Mound (eastern Porcupine Seabight; NE Atlantic) not only retrieved the first complete developmental history of a coral carbonate mound, it also exposed a unique, Early-Pleistocene sedimentary sequence of exceptional resolution along the mid-latitudinal NE Atlantic margin. In this study, a comprehensive assessment of the Challenger Mound as an archive of Quaternary palaeo-environmental change and long-term coral carbonate mound development is presented. New and existing environmental proxy records, including clay mineralogy, planktonic foraminifer and calcareous nannofossil biostratigraphy and assemblage counts, planktonic foraminifer oxygen isotopes and siliciclastic particle-size, are thereby discussed within a refined chronostratigraphic and climatic context. Overall, the development of the Challenger Mound shows a strong affinity to the Plio-Pleistocene evolution of the Northern Hemisphere climate system, albeit not being completely in phase with it. The two major oceanographic and climatic transitions of the Plio-Pleistocene - the Late Pliocene/Early Pleistocene intensification of continental ice-sheet development and the mid-Pleistocene transition to the more extremely variable and more extensively glaciated late Quaternary - mark two major thresholds in Challenger Mound development: its Late Pliocene (>2.74 Ma) origin and its Middle-Late Pleistocene to recent decline. Distinct surface-water perturbations (i.e. water-mass/polar front migrations, productivity changes, melt-water pulses) are identified throughout the sequence, which can be linked to the intensity and extent of ice development on the nearby British-Irish Isles since the earliest Pleistocene. Glaciation-induced shifts in surface-water primary productivity are thereby proposed to fundamentally control cold-water coral growth, which in turn influences on-mound sediment accumulation and, hence, coral carbonate mound development throughout the Pleistocene. As local factors, such as proximal ice-sheet dynamics and on-mound changes in cold-water coral density, significantly affected the development of the Challenger Mound, they can potentially explain the nature of its palaeo-record and its offsets with the periodicities of global climate variability. On the other hand, owing to this unique setting, a regionally exceptional, high-resolution palaeo-record of Early Pleistocene (ca 2.6 to 2.1 Ma) environmental change (including early British-Irish ice-sheet development), broadly in phase with the 41 ka-paced global climate system, is preserved in the lower Challenger Mound. All in all, the Challenger Mound record highlights the wider relevance of coral carbonate mound archives and their potential to capture unique records from dynamic (continental margin) environments.

Drought Monitoring and Forecasting: Experiences from the US and Africa

NASA Astrophysics Data System (ADS)

Sheffield, Justin; Chaney, Nate; Yuan, Xing; Wood, Eric

2013-04-01

Drought has important but very different consequences regionally due to differences in vulnerability. These differences derive from variations in exposure related to climate variability and change, sensitivity of local populations, and coping capacity at all levels. Managing the risk of drought impacts relies on a variety of measures to reduce vulnerability that includes forewarning of drought development through early-warning systems. Existing systems rely on a variety of observing systems from satellites to local observers, modeling tools, and data dissemination methods. They range from sophisticated state-of-the-art systems to simple ground reports. In some regions, systems are virtually non-existent due to limited national capacity. This talk describes our experiences in developing and implementing drought monitoring and seasonal forecast systems in the US and sub-Saharan Africa as contrasting examples of the scientific challenges and user needs in developing early warning systems. In particular, early warning can help improve livelihoods based on subsistence farming in sub-Saharan Africa; whist reduction of economic impacts is generally foremost in the US. For the US, our national drought monitoring and seasonal forecast system has been operational for over 8 years and provides near real-time updates on hydrological states at ~12km resolution and hydrological forecasts out to 9 months. Output from the system contributes to national assessments such as from the NOAA Climate Prediction Center (CPC) and the US National Drought Monitor (USDM). For sub-Saharan Africa, our experimental drought monitoring system was developed as a translation of the US system but presents generally greater challenges due to, for example, lack of ground data and unique user needs. The system provides near real-time updates based on hydrological modeling and satellite based precipitation estimates, and has recently been augmented by a seasonal forecast component. We discuss the differences in experiences in development and implementation between the two systems in terms of the scientific challenges and the utility of the systems to stakeholders, for whom the information must be relevant to local conditions and needs.

Yarkovsky-driven Impact Predictions: Apophis and 1950 DA

NASA Astrophysics Data System (ADS)

Farnocchia, Davide; Chesley, S. R.; Chodas, P.; Milani, A.

2013-05-01

Abstract (2,250 Maximum Characters): Orbit determination for Near-Earth Asteroids presents unique technical challenges due to the imperative of early detection and careful assessment of the risk posed by specific Earth close approaches. The occurrence of an Earth impact can be decisively driven by the Yarkovsky effect, which is the most important nongravitational perturbation as it causes asteroids to undergo a secular variation in semimajor axis resulting in a quadratic effect in anomaly. We discuss the cases of (99942) Apophis and (29075) 1950 DA. The relevance of the Yarkovsky effect for Apophis is due to a scattering close approach in 2029 with minimum geocentric distance ~38000 km. For 1950 DA the influence of the Yarkovsky effect in 2880 is due to the long time interval preceding the impact. We use the available information on the asteroids' physical models as a starting point for a Monte Carlo method that allow us to measure how the Yarkovsky effect affects orbital predictions. For Apophis we map onto the 2029 close approach b-plane and analyze the keyholes corresponding to resonant close approaches. For 1950 DA we use the b-plane corresponding to the possible impact in 2880. We finally compute the impact probability from the mapped probability density function on the considered b-plane.

CVD growth of large-area and high-quality HfS2 nanoforest on diverse substrates

NASA Astrophysics Data System (ADS)

Zheng, Binjie; Wang, Zegao; Qi, Fei; Wang, Xinqiang; Yu, Bo; Zhang, Wanli; Chen, Yuanfu

2018-03-01

Two-dimensional layered transition metal dichalcogenides (TMDs) have attracted burgeoning attention due to their various properties and wide potential applications. As a new TMD, hafnium disulfide (HfS2) is theoretically predicted to have better electrical performance than widely studied MoS2. The experimental researches also confirmed the extraordinary feature in electronics and optoelectronics. However, the maximal device performance may not be achieved due to its own limitation of planar structure and challenge of transfer without contamination. Here, through the chemical vapor deposition (CVD) technique, inch-size HfS2 nanoforest has been directly grown on diverse objective substrates covering insulating, semiconducting and conducting substrates. This direct CVD growth without conventional transfer process avoids contamination and degradation in quality, suggesting its promising and wide applications in high-quality and multifarious devices. It is noted that all the HfS2 nanoforests grown on diverse substrates are constructed with vertically aligned few-layered HfS2 nanosheets with high crystalline quality and edge orientation. Moreover, due to its unique structure, the HfS2 nanoforest owns abundant exposed edge sites and large active surface area, which is essential to apply in high-performance catalyst, sensor, and energy storage or field emitter.

Mental Health Research in Correctional Settings: Perceptions of Risk and Vulnerabilities

PubMed Central

Johnson, Mark E.; Kondo, Karli K.; Brems, Christiane; Ironside, Erica F.; Eldridge, Gloria D.

2015-01-01

With over half of individuals incarcerated having serious mental health concerns, correctional settings offer excellent opportunities for epidemiological, prevention, and intervention research. However, due to unique ethical and structural challenges, these settings create risks and vulnerabilities for participants not typically encountered in research populations. We surveyed 1,224 researchers, IRB members, and IRB prisoner representatives to assess their perceptions of risks associated with mental health research conducted in correctional settings. Highest-ranked risks were related to privacy, stigma, and confidentiality; lowest-ranked risks were related to prisoners’ loss of privileges or becoming targets of violence due to having participated in research. Cognitive impairment, mental illness, lack of autonomy, and limited access to services emerged as the greatest sources of vulnerability; being male, being female, being over age of 60, being a minority, and being pregnant were the lowest-ranked sources of vulnerability. Researchers with corrections experience perceived lower risks and vulnerabilities than all other groups, raising the question whether these researchers accurately appraise risk and vulnerability based on experience, or if their lower risk and vulnerability perceptions reflect potential bias due to their vested interests. By identifying areas of particular risk and vulnerability, this study provides important information for researchers and research reviewers alike. PMID:27092025