Testing Scientific Software: A Systematic Literature Review

PubMed Central

Kanewala, Upulee; Bieman, James M.

2014-01-01

Context Scientific software plays an important role in critical decision making, for example making weather predictions based on climate models, and computation of evidence for research publications. Recently, scientists have had to retract publications due to errors caused by software faults. Systematic testing can identify such faults in code. Objective This study aims to identify specific challenges, proposed solutions, and unsolved problems faced when testing scientific software. Method We conducted a systematic literature survey to identify and analyze relevant literature. We identified 62 studies that provided relevant information about testing scientific software. Results We found that challenges faced when testing scientific software fall into two main categories: (1) testing challenges that occur due to characteristics of scientific software such as oracle problems and (2) testing challenges that occur due to cultural differences between scientists and the software engineering community such as viewing the code and the model that it implements as inseparable entities. In addition, we identified methods to potentially overcome these challenges and their limitations. Finally we describe unsolved challenges and how software engineering researchers and practitioners can help to overcome them. Conclusions Scientific software presents special challenges for testing. Specifically, cultural differences between scientist developers and software engineers, along with the characteristics of the scientific software make testing more difficult. Existing techniques such as code clone detection can help to improve the testing process. Software engineers should consider special challenges posed by scientific software such as oracle problems when developing testing techniques. PMID:25125798

Process variation challenges and resolution in the negative-tone develop double patterning for 20nm and below technology node

NASA Astrophysics Data System (ADS)

Mehta, Sohan S.; Ganta, Lakshmi K.; Chauhan, Vikrant; Wu, Yixu; Singh, Sunil; Ann, Chia; Subramany, Lokesh; Higgins, Craig; Erenturk, Burcin; Srivastava, Ravi; Singh, Paramjit; Koh, Hui Peng; Cho, David

2015-03-01

Immersion based 20nm technology node and below becoming very challenging to chip designers, process and integration due to multiple patterning to integrate one design layer . Negative tone development (NTD) processes have been well accepted by industry experts for enabling technologies 20 nm and below. 193i double patterning is the technology solution for pitch down to 80 nm. This imposes tight control in critical dimension(CD) variation in double patterning where design patterns are decomposed in two different masks such as in litho-etch-litho etch (LELE). CD bimodality has been widely studied in LELE double patterning. A portion of CD tolerance budget is significantly consumed by variations in CD in double patterning. The objective of this work is to study the process variation challenges and resolution in the Negative Tone Develop Process for 20 nm and Below Technology Node. This paper describes the effect of dose slope on CD variation in negative tone develop LELE process. This effect becomes even more challenging with standalone NTD developer process due to q-time driven CD variation. We studied impact of different stacks with combination of binary and attenuated phase shift mask and estimated dose slope contribution individually from stack and mask type. Mask 3D simulation was carried out to understand theoretical aspect. In order to meet the minimum insulator requirement for the worst case on wafer the overlay and critical dimension uniformity (CDU) budget margins have slimmed. Besides the litho process and tool control using enhanced metrology feedback, the variation control has other dependencies too. Color balancing between the two masks in LELE is helpful in countering effects such as iso-dense bias, and pattern shifting. Dummy insertion and the improved decomposition techniques [2] using multiple lower priority constraints can help to a great extent. Innovative color aware routing techniques [3] can also help with achieving more uniform density and color balanced layouts.

77 FR 75355 - Bill of Rights Day, 2012

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-19

... that the freedoms it protects--among them speech, worship, assembly, and due process--are freedoms that... that challenge. They have been defenders who stood watch at freedom's frontier, marchers who broke down...

Board of Curators of the University of Missouri v. Horowitz: Student Due Process Rights and Judicial Deference to Academic Dismissals.

ERIC Educational Resources Information Center

Brock, Allan D.

1979-01-01

The Horowitz case is consistent with the general reluctance of courts to sustain constitutional challenges to decisions by educators in academic matters. Precedent is heavily weighted in favor of the academic community and should be overcome in future challenges. (Journal availability: Willamette University College of Law, Salem, OR 97301, $5.00…

Nanotechnology in meat processing and packaging: potential applications - a review.

PubMed

Ramachandraiah, Karna; Han, Sung Gu; Chin, Koo Bok

2015-02-01

Growing demand for sustainable production, increasing competition and consideration of health concerns have led the meat industries on a path to innovation. Meat industries across the world are focusing on the development of novel meat products and processes to meet consumer demand. Hence, a process innovation, like nanotechnology, can have a significant impact on the meat processing industry through the development of not only novel functional meat products, but also novel packaging for the products. The potential benefits of utilizing nanomaterials in food are improved bioavailability, antimicrobial effects, enhanced sensory acceptance and targeted delivery of bioactive compounds. However, challenges exist in the application of nanomaterials due to knowledge gaps in the production of ingredients such as nanopowders, stability of delivery systems in meat products and health risks caused by the same properties which also offer the benefits. For the success of nanotechnology in meat products, challenges in public acceptance, economics and the regulation of food processed with nanomaterials which may have the potential to persist, accumulate and lead to toxicity need to be addressed. So far, the most promising area for nanotechnology application seems to be in meat packaging, but the long term effects on human health and environment due to migration of the nanomaterials from the packaging needs to be studied further. The future of nanotechnology in meat products depends on the roles played by governments, regulatory agencies and manufacturers in addressing the challenges related to the application of nanomaterials in food.

Nanotechnology in Meat Processing and Packaging: Potential Applications — A Review

PubMed Central

Ramachandraiah, Karna; Han, Sung Gu; Chin, Koo Bok

2015-01-01

Growing demand for sustainable production, increasing competition and consideration of health concerns have led the meat industries on a path to innovation. Meat industries across the world are focusing on the development of novel meat products and processes to meet consumer demand. Hence, a process innovation, like nanotechnology, can have a significant impact on the meat processing industry through the development of not only novel functional meat products, but also novel packaging for the products. The potential benefits of utilizing nanomaterials in food are improved bioavailability, antimicrobial effects, enhanced sensory acceptance and targeted delivery of bioactive compounds. However, challenges exist in the application of nanomaterials due to knowledge gaps in the production of ingredients such as nanopowders, stability of delivery systems in meat products and health risks caused by the same properties which also offer the benefits. For the success of nanotechnology in meat products, challenges in public acceptance, economics and the regulation of food processed with nanomaterials which may have the potential to persist, accumulate and lead to toxicity need to be addressed. So far, the most promising area for nanotechnology application seems to be in meat packaging, but the long term effects on human health and environment due to migration of the nanomaterials from the packaging needs to be studied further. The future of nanotechnology in meat products depends on the roles played by governments, regulatory agencies and manufacturers in addressing the challenges related to the application of nanomaterials in food. PMID:25557827

New Processes for Freeze-Drying in Dual-Chamber Systems.

PubMed

Werk, T; Ludwig, I S; Luemkemann, J; Huwyler, J; Mahler, H-C; Haeuser, C R; Hafner, M

2016-01-01

Dual-chamber systems can offer self-administration and home care use for lyophilized biologics. Only a few products have been launched in dual-chamber systems so far-presumably due to dual-chamber systems' complex and costly drug product manufacturing process. Within this paper, two improved processes (both based on tray filling technology) for freeze-drying pharmaceuticals in dual-chamber systems are described. Challenges with regards to heat transfer were tackled by (1) performing the freeze-drying step in a needle-down orientation in combination with an aluminum block, or (2) freeze-drying the drug product "externally" in a metal cartridge with subsequent filling of the lyophilized cake into the dual-chamber system. Metal-mediated heat transfer was shown to be efficient in both cases and batch (unit-to-unit) homogeneity with regards to sublimation rate was increased. It was difficult to influence ice crystal size using different methods when in use with an aluminum block due to its heat capacity. Using such a metal carrier implies a large heat capacity leading to relatively small ice crystals. Compared to the established process, drying times were reduced by half using the new processes. The drying time was, however, longer for syringes compared to vials due to the syringe design (long and slim). The differences in drying times were less pronounced for aggressive drying cycles. The proposed processes may help to considerably decrease investment costs into dual-chamber system fill-finish equipment. Dual-chamber syringes offer self-administration and home care use for freeze-dried pharmaceuticals. Only a few products have been launched in dual-chamber syringes so far-presumably due to their complex and costly drug product manufacturing process. In this paper two improved processes for freeze-drying pharmaceuticals in dual-chamber syringes are described. The major challenge of freeze-drying is to transfer heat through a vacuum. The proposed processes cope with this challenge by (1) freeze-drying the drug product in the syringe in an orientation in which the product is closest to the heat source, or (2) freeze-drying the drug product outside the syringe in a metal tube. The latter requires filling the freeze-dried product subsequently into the dual-chamber syringe. Both processes were very efficient and promised to achieve similar freeze-drying conditions for all dual-chamber syringes within one production run. The proposed processes may help to considerably decrease investment costs into dual-chamber syringe fill-finish equipment. © PDA, Inc. 2016.

Recent Advances and Challenges towards Sustainable Polyhydroxyalkanoate (PHA) Production.

PubMed

Kourmentza, Constantina; Plácido, Jersson; Venetsaneas, Nikolaos; Burniol-Figols, Anna; Varrone, Cristiano; Gavala, Hariklia N; Reis, Maria A M

2017-06-11

Sustainable biofuels, biomaterials, and fine chemicals production is a critical matter that research teams around the globe are focusing on nowadays. Polyhydroxyalkanoates represent one of the biomaterials of the future due to their physicochemical properties, biodegradability, and biocompatibility. Designing efficient and economic bioprocesses, combined with the respective social and environmental benefits, has brought together scientists from different backgrounds highlighting the multidisciplinary character of such a venture. In the current review, challenges and opportunities regarding polyhydroxyalkanoate production are presented and discussed, covering key steps of their overall production process by applying pure and mixed culture biotechnology, from raw bioprocess development to downstream processing.

Truth in Testing Legislation and Private Property Concepts.

ERIC Educational Resources Information Center

Burns, Daniel J.

1981-01-01

Truth in testing laws are subject to challenge on the grounds that they invade federally protected rights and interests of the test-makers through the due process clauses of the Constitution and federal copyright protections. (Author/MLF)

Voice Onset Time in Consonant Cluster Errors: Can Phonetic Accommodation Differentiate Cognitive from Motor Errors?

ERIC Educational Resources Information Center

Pouplier, Marianne; Marin, Stefania; Waltl, Susanne

2014-01-01

Purpose: Phonetic accommodation in speech errors has traditionally been used to identify the processing level at which an error has occurred. Recent studies have challenged the view that noncanonical productions may solely be due to phonetic, not phonological, processing irregularities, as previously assumed. The authors of the present study…

Using Networks to Visualize and Analyze Process Data for Educational Assessment

ERIC Educational Resources Information Center

Zhu, Mengxiao; Shu, Zhan; von Davier, Alina A.

2016-01-01

New technology enables interactive and adaptive scenario-based tasks (SBTs) to be adopted in educational measurement. At the same time, it is a challenging problem to build appropriate psychometric models to analyze data collected from these tasks, due to the complexity of the data. This study focuses on process data collected from SBTs. We…

Evaluating crown fire rate of spread predictions from physics-based models

Treesearch

C. M. Hoffman; J. Ziegler; J. Canfield; R. R. Linn; W. Mell; C. H. Sieg; F. Pimont

2015-01-01

Modeling the behavior of crown fires is challenging due to the complex set of coupled processes that drive the characteristics of a spreading wildfire and the large range of spatial and temporal scales over which these processes occur. Detailed physics-based modeling approaches such as FIRETEC and the Wildland Urban Interface Fire Dynamics Simulator (WFDS) simulate...

Atmospheric rivers and past hydrometeorological extremes: Challenges and opportunities

NASA Astrophysics Data System (ADS)

Sodemann, Harald

2017-04-01

Atmospheric rivers are a key term for describing water vapour transport in extratropical regions. The concept has become particularly valuable for linking meteorological process understanding with research focused on the impacts of heavy precipitation. Atmospheric rivers are narrow, elongated features of high integrated water vapour and water vapour flux can lead to severe precipitation and flooding if moisture is extracted efficiently. The orographic rises at the West Coast of the United States and Western Norway are regions where Atmospheric Rivers are one of the prime mechanisms for moisture delivery and precipitation extremes in the present climate. Due to the small horizontal scales of some of the processes climate models are challenged to represent this important transport process between mid-latitudes and the subtropics faithfully. Recent aircraft data and regional tracer model studies provide new insight into the formation and moisture transport mechanisms. In this study I review the concept and pertinent processes of Atmospheric Rivers, thereby focusing on caveats, challenges and opportunities for understanding past hydrometeorological extremes.

Corrosion Challenges for the Oil and Gas Industry in the State of Qatar

NASA Astrophysics Data System (ADS)

Johnsen, Roy

In Qatar oil and gas has been produced from onshore fields in more than 70 years, while the first offshore field delivered its first crude oil in 1965. Due to the atmospheric conditions in Qatar with periodically high humidity, high chloride content, dust/sand combined with the temperature variations, external corrosion is a big treat to the installations and connecting infrastructure. Internal corrosion in tubing, piping and process systems is also a challenge due to high H2S content in the hydrocarbon mixture and exposure to corrosive aquifer water. To avoid corrosion different type of mitigations like application of coating, chemical treatment and material selection are important elements. This presentation will review the experiences with corrosion challenges for oil & gas installations in Qatar including some examples of corrosion failures that have been seen.

Composting technology in waste stabilization: On the methods, challenges and future prospects.

PubMed

Onwosi, Chukwudi O; Igbokwe, Victor C; Odimba, Joyce N; Eke, Ifeanyichukwu E; Nwankwoala, Mary O; Iroh, Ikemdinachi N; Ezeogu, Lewis I

2017-04-01

Composting technology has become invaluable in stabilization of municipal waste due to its environmental compatibility. In this review, different types of composting methods reportedly applied in waste management were explored. Further to that, the major factors such as temperature, pH, C/N ratio, moisture, particle size that have been considered relevant in the monitoring of the composting process were elucidated. Relevant strategies to improve and optimize process effectiveness were also addressed. However, during composting, some challenges such as leachate generation, gas emission and lack of uniformity in assessing maturity indices are imminent. Here in, these challenges were properly addressed and some strategies towards ameliorating them were proffered. Finally, we highlighted some recent technologies that could improve composting. Copyright © 2016 Elsevier Ltd. All rights reserved.

Modeling and simulation of the fluid flow in wire electrochemical machining with rotating tool (wire ECM)

NASA Astrophysics Data System (ADS)

Klocke, F.; Herrig, T.; Zeis, M.; Klink, A.

2017-10-01

Combining the working principle of electrochemical machining (ECM) with a universal rotating tool, like a wire, could manage lots of challenges of the classical ECM sinking process. Such a wire-ECM process could be able to machine flexible and efficient 2.5-dimensional geometries like fir tree slots in turbine discs. Nowadays, established manufacturing technologies for slotting turbine discs are broaching and wire electrical discharge machining (wire EDM). Nevertheless, high requirements on surface integrity of turbine parts need cost intensive process development and - in case of wire-EDM - trim cuts to reduce the heat affected rim zone. Due to the process specific advantages, ECM is an attractive alternative manufacturing technology and is getting more and more relevant for sinking applications within the last few years. But ECM is also opposed with high costs for process development and complex electrolyte flow devices. In the past, few studies dealt with the development of a wire ECM process to meet these challenges. However, previous concepts of wire ECM were only suitable for micro machining applications. Due to insufficient flushing concepts the application of the process for machining macro geometries failed. Therefore, this paper presents the modeling and simulation of a new flushing approach for process assessment. The suitability of a rotating structured wire electrode in combination with an axial flushing for electrodes with high aspect ratios is investigated and discussed.

Application of advanced diffraction based optical metrology overlay capabilities for high-volume manufacturing

NASA Astrophysics Data System (ADS)

Chen, Kai-Hsiung; Huang, Guo-Tsai; Hsieh, Hung-Chih; Ni, Wei-Feng; Chuang, S. M.; Chuang, T. K.; Ke, Chih-Ming; Huang, Jacky; Rao, Shiuan-An; Cumurcu Gysen, Aysegul; d'Alfonso, Maxime; Yueh, Jenny; Izikson, Pavel; Soco, Aileen; Wu, Jon; Nooitgedagt, Tjitte; Ottens, Jeroen; Kim, Yong Ho; Ebert, Martin

2017-03-01

On-product overlay requirements are becoming more challenging with every next technology node due to the continued decrease of the device dimensions and process tolerances. Therefore, current and future technology nodes require demanding metrology capabilities such as target designs that are robust towards process variations and high overlay measurement density (e.g. for higher order process corrections) to enable advanced process control solutions. The impact of advanced control solutions based on YieldStar overlay data is being presented in this paper. Multi patterning techniques are applied for critical layers and leading to additional overlay measurement demands. The use of 1D process steps results in the need of overlay measurements relative to more than one layer. Dealing with the increased number of overlay measurements while keeping the high measurement density and metrology accuracy at the same time presents a challenge for high volume manufacturing (HVM). These challenges are addressed by the capability to measure multi-layer targets with the recently introduced YieldStar metrology tool, YS350. On-product overlay results of such multi-layers and standard targets are presented including measurement stability performance.

Recent Advances and Challenges towards Sustainable Polyhydroxyalkanoate (PHA) Production

PubMed Central

Kourmentza, Constantina; Plácido, Jersson; Venetsaneas, Nikolaos; Burniol-Figols, Anna; Varrone, Cristiano; Gavala, Hariklia N.; Reis, Maria A. M.

2017-01-01

Sustainable biofuels, biomaterials, and fine chemicals production is a critical matter that research teams around the globe are focusing on nowadays. Polyhydroxyalkanoates represent one of the biomaterials of the future due to their physicochemical properties, biodegradability, and biocompatibility. Designing efficient and economic bioprocesses, combined with the respective social and environmental benefits, has brought together scientists from different backgrounds highlighting the multidisciplinary character of such a venture. In the current review, challenges and opportunities regarding polyhydroxyalkanoate production are presented and discussed, covering key steps of their overall production process by applying pure and mixed culture biotechnology, from raw bioprocess development to downstream processing. PMID:28952534

Challenges in process marginality for advanced technology nodes and tackling its contributors

NASA Astrophysics Data System (ADS)

Narayana Samy, Aravind; Schiwon, Roberto; Seltmann, Rolf; Kahlenberg, Frank; Katakamsetty, Ushasree

2013-10-01

Process margin is getting critical in the present node shrinkage scenario due to the physical limits reached (Rayleigh's criterion) using ArF lithography tools. K1 is used to its best for better resolution and to enhance the process margin (28nm metal patterning k1=0.31). In this paper, we would like to give an overview of various contributors in the advanced technology nodes which limit the process margins and how the challenges have been tackled in a modern foundry model. Advanced OPC algorithms are used to make the design content at the mask optimum for patterning. However, as we work at the physical limit, critical features (Hot-spots) are very susceptible to litho process variations. Furthermore, etch can have a significant impact as well. Pattern that still looks healthy at litho can fail due to etch interactions. This makes the traditional 2D contour output from ORC tools not able to predict accurately all defects and hence not able to fully correct it in the early mask tapeout phase. The above makes a huge difference in the fast ramp-up and high yield in a competitive foundry market. We will explain in this paper how the early introduction of 3D resist model based simulation of resist profiles (resist top-loss, bottom bridging, top-rounding, etc.,) helped in our prediction and correction of hot-spots in the early 28nm process development phase. The paper also discusses about the other overall process window reduction contributors due to mask 3D effects, wafer topography (focus shifts/variations) and how this has been addressed with different simulation efforts in a fast and timely manner.

Additive manufacturing for steels: a review

NASA Astrophysics Data System (ADS)

Zadi-Maad, A.; Rohib, R.; Irawan, A.

2018-01-01

Additive manufacturing (AM) of steels involves the layer by layer consolidation of powder or wire feedstock using a heating beam to form near net shape products. For the past decades, the AM technique reaches the maturation of both research grade and commercial production due to significant research work from academic, government and industrial research organization worldwide. AM process has been implemented to replace the conventional process of steel fabrication due to its potentially lower cost and flexibility manufacturing. This paper provides a review of previous research related to the AM methods followed by current challenges issues. The relationship between microstructure, mechanical properties, and process parameters will be discussed. Future trends and recommendation for further works are also provided.

Ecological and genetic systems underlying sustainable horticulture

USDA-ARS?s Scientific Manuscript database

Agriculture in the 21st century will face unprecedented challenges due to rising energy costs, global climate change, and increasingly scarce production resources. It will become imperative for producers to adopt sustainable systems that rely on natural system processes and use inputs as efficientl...

A comparative study of ethylene oxide gas, hydrogen peroxide gas plasma, and low-temperature steam formaldehyde sterilization.

PubMed

Kanemitsu, Keiji; Imasaka, Takayuki; Ishikawa, Shiho; Kunishima, Hiroyuki; Harigae, Hideo; Ueno, Kumi; Takemura, Hiromu; Hirayama, Yoshihiro; Kaku, Mitsuo

2005-05-01

To compare the efficacies of ethylene oxide gas (EOG), hydrogen peroxide gas plasma (PLASMA), and low-temperature steam formaldehyde (LTSF) sterilization methods. The efficacies of EOG, PLASMA, and LTSF sterilization were tested using metal and plastic plates, common medical instruments, and three process challenge devices with narrow lumens. All items were contaminated with Bacillus stearothermophilus spores or used a standard biological indicator. EOG and LTSF demonstrated effective killing of B. stearothermophilus spores, with or without serum, on plates, on instruments, and in process challenge devices. PLASMA failed to adequately sterilize materials on multiple trials in several experiments, including two of three plates, two of three instruments, and all process challenge devices. Our results suggest that PLASMA sterilization may be unsuccessful under certain conditions, particularly when used for items with complex shapes and narrow lumens. Alternatively, LTSF sterilization demonstrates excellent efficacy and is comparable to EOG sterilization. LTSF could potentially act as a substitute if EOG becomes unavailable due to environmental concerns.

Recycled poly(ethylene terephthalate) for direct food contact applications: challenge test of an inline recycling process.

PubMed

Franz, R; Welle, F

2002-05-01

Of all the plastics used for packaging, due to its low diffusivity and chemical inertness, poly(ethylene terephthalate) (PET) is one of the favoured candidate plastics for closed-loop recycling for new packaging applications. In the work reported here, a PET-recycling process was investigated with respect to its cleaning efficiency and compliance of the PET recyclate with food law. The key technology of the investigated PET-recycling process to remove contaminants consists of a predecontamination-extruder combination. At the end of the recycling process, there is either a pelletizing system or downstream equipment to produce preforms or flat sheets. Therefore, the process has two process options, an inline production of PET preforms and a batch option producing PET pellets. In the case of possible misuse of PET bottles by the consumer, the inline process produces higher concentrations in the bottle wall of the recyclate containing preforms. Owing to the dilution of the PET output material by large amounts of uncontaminated PET, the batch option is the less critical process in terms of consumer protection. Regarding an appropriate testing procedure for the evaluation of a bottle-to-bottle recycling process, both process options have their own specific requirements with respect to the design of a challenge test. A novel challenge test approach to the inline mode of a recycling process is presented here.

Automotive HMI design and participatory user involvement: review and perspectives.

PubMed

François, Mathilde; Osiurak, François; Fort, Alexandra; Crave, Philippe; Navarro, Jordan

2017-04-01

Automotive human-machine interface (HMI) design is facing new challenges due to the technological advances of the last decades. The design process has to be adapted in order to address human factors and road safety challenges. It is now widely accepted that user involvement in the HMI design process is valuable. However, the current form of user involvement in industry remains at the stages of concept assessment and usability tests. Moreover, the literature in other fields (e.g. information systems) promotes a broader user involvement with participatory design (i.e. the user is fully involved in the development process). This article reviews the established benefits of participatory design and reveals perspectives for automotive HMI quality improvement in a cognitive ergonomic framework. Practitioner Summary: Automotive HMI quality determines, in part, drivers' ability to perform primary driving tasks while using in-vehicle devices. User involvement in the design process is a key point to contribute to HMI quality. This article reports the potential benefits of a broad involvement from drivers to meet automotive HMI design challenges.

Thermographic In-Situ Process Monitoring of the Electron Beam Melting Technology used in Additive Manufacturing

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

Dinwiddie, Ralph Barton; Dehoff, Ryan R; Lloyd, Peter D

2013-01-01

Oak Ridge National Laboratory (ORNL) has been utilizing the ARCAM electron beam melting technology to additively manufacture complex geometric structures directly from powder. Although the technology has demonstrated the ability to decrease costs, decrease manufacturing lead-time and fabricate complex structures that are impossible to fabricate through conventional processing techniques, certification of the component quality can be challenging. Because the process involves the continuous deposition of successive layers of material, each layer can be examined without destructively testing the component. However, in-situ process monitoring is difficult due to metallization on inside surfaces caused by evaporation and condensation of metal from themore » melt pool. This work describes a solution to one of the challenges to continuously imaging inside of the chamber during the EBM process. Here, the utilization of a continuously moving Mylar film canister is described. Results will be presented related to in-situ process monitoring and how this technique results in improved mechanical properties and reliability of the process.« less

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.

Trend and current practices of palm oil mill effluent polishing: Application of advanced oxidation processes and their future perspectives.

PubMed

Bello, Mustapha Mohammed; Abdul Raman, Abdul Aziz

2017-08-01

Palm oil processing is a multi-stage operation which generates large amount of effluent. On average, palm oil mill effluent (POME) may contain up to 51, 000 mg/L COD, 25,000 mg/L BOD, 40,000 TS and 6000 mg/L oil and grease. Due to its potential to cause environmental pollution, palm oil mills are required to treat the effluent prior to discharge. Biological treatments using open ponding system are widely used for POME treatment. Although these processes are capable of reducing the pollutant concentrations, they require long hydraulic retention time and large space, with the effluent frequently failing to satisfy the discharge regulation. Due to more stringent environmental regulations, research interest has recently shifted to the development of polishing technologies for the biologically-treated POME. Various technologies such as advanced oxidation processes, membrane technology, adsorption and coagulation have been investigated. Among these, advanced oxidation processes have shown potentials as polishing technologies for POME. This paper offers an overview on the POME polishing technologies, with particularly emphasis on advanced oxidation processes and their prospects for large scale applications. Although there are some challenges in large scale applications of these technologies, this review offers some perspectives that could help in overcoming these challenges. Copyright © 2017 Elsevier Ltd. All rights reserved.

Selective dry etching of silicon containing anti-reflective coating

NASA Astrophysics Data System (ADS)

Sridhar, Shyam; Nolan, Andrew; Wang, Li; Karakas, Erdinc; Voronin, Sergey; Biolsi, Peter; Ranjan, Alok

2018-03-01

Multi-layer patterning schemes involve the use of Silicon containing Anti-Reflective Coating (SiARC) films for their anti-reflective properties. Patterning transfer completion requires complete and selective removal of SiARC which is very difficult due to its high silicon content (>40%). Typically, SiARC removal is accomplished through a non-selective etch during the pattern transfer process using fluorine containing plasmas, or an ex-situ wet etch process using hydrofluoric acid is employed to remove the residual SiARC, post pattern transfer. Using a non-selective etch may result in profile distortion or wiggling, due to distortion of the underlying organic layer. The drawbacks of using wet etch process for SiARC removal are increased overall processing time and the need for additional equipment. Many applications may involve patterning of active structures in a poly-Si layer with an underlying oxide stopping layer. In such applications, SiARC removal selective to oxide using a wet process may prove futile. Removing SiARC selectively to SiO2 using a dry etch process is also challenging, due to similarity in the nature of chemical bonds (Si - O) in the two materials. In this work, we present highly selective etching of SiARC, in a plasma driven by a surface wave radial line slot antenna. The first step in the process involves an in-situ modification of the SiARC layer in O2 plasma followed by selective etching in a NF3/H2 plasma. Surface treatment in O2 plasma resulted in enhanced etching of the SiARC layer. For the right processing conditions, in-situ NF3/H2 dry etch process demonstrated selectivity values greater than 15:1 with respect to SiO2. The etching chemistry, however, was sensitive to NF3:H2 gas ratio. For dilute NF3 in H2, no SiARC etching was observed. Presumably, this is due to the deposition of ammonium fluorosilicate layer that occurs for dilute NF3/H2 plasmas. Additionally, challenges involved in selective SiARC removal (selective to SiO2, organic and Si layers) post pattern transfer, in a multi-layer structure will be discussed.

A Software Development Simulation Model of a Spiral Process

NASA Technical Reports Server (NTRS)

Mizell, Carolyn; Malone, Linda

2007-01-01

There is a need for simulation models of software development processes other than the waterfall because processes such as spiral development are becoming more and more popular. The use of a spiral process can make the inherently difficult job of cost and schedule estimation even more challenging due to its evolutionary nature, but this allows for a more flexible process that can better meet customers' needs. This paper will present a discrete event simulation model of spiral development that can be used to analyze cost and schedule effects of using such a process in comparison to a waterfall process.

"Board of Curators of the University of Missouri v. Horowitz": Student Due Process Rights and Judicial Deference to Academic Dismissals.

ERIC Educational Resources Information Center

Brock, Allan D.

1979-01-01

The "Horowitz" case is consistent with the general reluctance of courts to sustain constitutional challenges to decisions by educators in academic matters. Available from Willamette University College of Law, Salem, OR 97301. (Author)

HYDROCARBON OXIDATION OVER VANADIUM PHOSPHORUS OXIDE CATALYST USING HYDROGEN PEROXIDE

EPA Science Inventory

Selective oxidation of hydrocarbons is one of the very important and challenging areas in industrial chemistry due to the wide ranging utility of the resulting oxygenates in fine chemical synthesis. Most of the existing processes for their oxidations employ toxic and often stoich...

A Comparison of three chromatographic retention time prediction models (ACS 2017 Fall meeting 2 of 3)

EPA Science Inventory

High resolution mass spectrometry (HRMS) data has revolutionized the identification of environmental contaminants through non-targeted analyses (NTA). However, data processing and chemical identification and prioritization remain challenging due to the vast number of unknowns ob...

Challenges of Global Change for Lakes

NASA Astrophysics Data System (ADS)

Seekell, D.

2016-12-01

Lakes comprise a tiny fraction of Earth's surface, but contribute significantly to human life and wellbeing. Many lakes are disappearing due to climate change and water diversions, and there are widespread disruptions to ecosystem processes due to human influences. For example, pollution by nutrients and toxic chemicals causes toxicity to humans, livestock, fish, and wildlife. Lake desiccation reduces economic opportunity and food security, displacing entire communities. Understanding these changes at the global scale, and their implications for human societies, are a key challenges for aquatic scientists. In this talk, I will use results from my research to highlight some of the key uncertainties related to global change and lakes, as well as recent developments by aquatic scientists aimed at predicting, mitigating, and coping with these changes.

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.

Sandwich ELISA Microarrays: Generating Reliable and Reproducible Assays for High-Throughput Screens

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

Gonzalez, Rachel M.; Varnum, Susan M.; Zangar, Richard C.

The sandwich ELISA microarray is a powerful screening tool in biomarker discovery and validation due to its ability to simultaneously probe for multiple proteins in a miniaturized assay. The technical challenges of generating and processing the arrays are numerous. However, careful attention to possible pitfalls in the development of your antibody microarray assay can overcome these challenges. In this chapter, we describe in detail the steps that are involved in generating a reliable and reproducible sandwich ELISA microarray assay.

Supporting Public Administration with an Integrated BPR Environment

NASA Astrophysics Data System (ADS)

Ciaghi, Aaron; Villafiorita, Adolfo; Weldemariam, Komminist; Mattioli, Andrea; Phan, Quoc-Sang

The definition or redesign of Public Administration (PA) procedures is particularly challenging. This is, for example, due to the requirement of cooperation of different organizational units and actors, different laws and procedures for the production of several artifacts, and maintaining traceability while integrating processes with new laws.

Systems metabolic engineering of microorganisms to achieve large-scale production of flavonoid scaffolds.

PubMed

Wu, Junjun; Du, Guocheng; Zhou, Jingwen; Chen, Jian

2014-10-20

Flavonoids possess pharmaceutical potential due to their health-promoting activities. The complex structures of these products make extraction from plants difficult, and chemical synthesis is limited because of the use of many toxic solvents. Microbial production offers an alternate way to produce these compounds on an industrial scale in a more economical and environment-friendly manner. However, at present microbial production has been achieved only on a laboratory scale and improvements and scale-up of these processes remain challenging. Naringenin and pinocembrin, which are flavonoid scaffolds and precursors for most of the flavonoids, are the model molecules that are key to solving the current issues restricting industrial production of these chemicals. The emergence of systems metabolic engineering, which combines systems biology with synthetic biology and evolutionary engineering at the systems level, offers new perspectives on strain and process optimization. In this review, current challenges in large-scale fermentation processes involving flavonoid scaffolds and the strategies and tools of systems metabolic engineering used to overcome these challenges are summarized. This will offer insights into overcoming the limitations and challenges of large-scale microbial production of these important pharmaceutical compounds. Copyright © 2014 Elsevier B.V. All rights reserved.

Peel-and-Stick: Fabricating Thin Film Solar Cell on Universal Substrates

PubMed Central

Lee, Chi Hwan; Kim, Dong Rip; Cho, In Sun; William, Nemeth; Wang, Qi; Zheng, Xiaolin

2012-01-01

Fabrication of thin-film solar cells (TFSCs) on substrates other than Si and glass has been challenging because these nonconventional substrates are not suitable for the current TFSC fabrication processes due to poor surface flatness and low tolerance to high temperature and chemical processing. Here, we report a new peel-and-stick process that circumvents these fabrication challenges by peeling off the fully fabricated TFSCs from the original Si wafer and attaching TFSCs to virtually any substrates regardless of materials, flatness and rigidness. With the peel-and-stick process, we integrated hydrogenated amorphous silicon (a-Si:H) TFSCs on paper, plastics, cell phone and building windows while maintaining the original 7.5% efficiency. The new peel-and-stick process enables further reduction of the cost and weight for TFSCs and endows TFSCs with flexibility and attachability for broader application areas. We believe that the peel-and-stick process can be applied to thin film electronics as well. PMID:23277871

Peel-and-Stick: Fabricating Thin Film Solar Cell on Universal Substrates

NASA Astrophysics Data System (ADS)

Lee, Chi Hwan; Kim, Dong Rip; Cho, In Sun; William, Nemeth; Wang, Qi; Zheng, Xiaolin

2012-12-01

Fabrication of thin-film solar cells (TFSCs) on substrates other than Si and glass has been challenging because these nonconventional substrates are not suitable for the current TFSC fabrication processes due to poor surface flatness and low tolerance to high temperature and chemical processing. Here, we report a new peel-and-stick process that circumvents these fabrication challenges by peeling off the fully fabricated TFSCs from the original Si wafer and attaching TFSCs to virtually any substrates regardless of materials, flatness and rigidness. With the peel-and-stick process, we integrated hydrogenated amorphous silicon (a-Si:H) TFSCs on paper, plastics, cell phone and building windows while maintaining the original 7.5% efficiency. The new peel-and-stick process enables further reduction of the cost and weight for TFSCs and endows TFSCs with flexibility and attachability for broader application areas. We believe that the peel-and-stick process can be applied to thin film electronics as well.

Quantum simulator review

NASA Astrophysics Data System (ADS)

Bednar, Earl; Drager, Steven L.

2007-04-01

Quantum information processing's objective is to utilize revolutionary computing capability based on harnessing the paradigm shift offered by quantum computing to solve classically hard and computationally challenging problems. Some of our computationally challenging problems of interest include: the capability for rapid image processing, rapid optimization of logistics, protecting information, secure distributed simulation, and massively parallel computation. Currently, one important problem with quantum information processing is that the implementation of quantum computers is difficult to realize due to poor scalability and great presence of errors. Therefore, we have supported the development of Quantum eXpress and QuIDD Pro, two quantum computer simulators running on classical computers for the development and testing of new quantum algorithms and processes. This paper examines the different methods used by these two quantum computing simulators. It reviews both simulators, highlighting each simulators background, interface, and special features. It also demonstrates the implementation of current quantum algorithms on each simulator. It concludes with summary comments on both simulators.

Biogas Production from Sugarcane Waste: Assessment on Kinetic Challenges for Process Designing.

PubMed

Janke, Leandro; Leite, Athaydes; Nikolausz, Marcell; Schmidt, Thomas; Liebetrau, Jan; Nelles, Michael; Stinner, Walter

2015-08-31

Biogas production from sugarcane waste has large potential for energy generation, however, to enable the optimization of the anaerobic digestion (AD) process each substrate characteristic should be carefully evaluated. In this study, the kinetic challenges for biogas production from different types of sugarcane waste were assessed. Samples of vinasse, filter cake, bagasse, and straw were analyzed in terms of total and volatile solids, chemical oxygen demand, macronutrients, trace elements, and nutritional value. Biochemical methane potential assays were performed to evaluate the energy potential of the substrates according to different types of sugarcane plants. Methane yields varied considerably (5-181 Nm³·tonFM(-1)), mainly due to the different substrate characteristics and sugar and/or ethanol production processes. Therefore, for the optimization of AD on a large-scale, continuous stirred-tank reactor with long hydraulic retention times (>35 days) should be used for biogas production from bagasse and straw, coupled with pre-treatment process to enhance the degradation of the fibrous carbohydrates. Biomass immobilization systems are recommended in case vinasse is used as substrate, due to its low solid content, while filter cake could complement the biogas production from vinasse during the sugarcane offseason, providing a higher utilization of the biogas system during the entire year.

Biogas Production from Sugarcane Waste: Assessment on Kinetic Challenges for Process Designing

PubMed Central

Janke, Leandro; Leite, Athaydes; Nikolausz, Marcell; Schmidt, Thomas; Liebetrau, Jan; Nelles, Michael; Stinner, Walter

2015-01-01

Biogas production from sugarcane waste has large potential for energy generation, however, to enable the optimization of the anaerobic digestion (AD) process each substrate characteristic should be carefully evaluated. In this study, the kinetic challenges for biogas production from different types of sugarcane waste were assessed. Samples of vinasse, filter cake, bagasse, and straw were analyzed in terms of total and volatile solids, chemical oxygen demand, macronutrients, trace elements, and nutritional value. Biochemical methane potential assays were performed to evaluate the energy potential of the substrates according to different types of sugarcane plants. Methane yields varied considerably (5–181 Nm3·tonFM−1), mainly due to the different substrate characteristics and sugar and/or ethanol production processes. Therefore, for the optimization of AD on a large-scale, continuous stirred-tank reactor with long hydraulic retention times (>35 days) should be used for biogas production from bagasse and straw, coupled with pre-treatment process to enhance the degradation of the fibrous carbohydrates. Biomass immobilization systems are recommended in case vinasse is used as substrate, due to its low solid content, while filter cake could complement the biogas production from vinasse during the sugarcane offseason, providing a higher utilization of the biogas system during the entire year. PMID:26404248

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.

The Legal Implications of Administrative Decision-Making.

ERIC Educational Resources Information Center

Bender, Louis W.

Administrative decision-making encompasses three levels on which increasing legal challenges and liability and their implications need to be considered. At the local level, this may involve violations of procedural due process. A second level concerns state laws and regulations. Line administrators, who frequently make decisions on programs,…

NCI-CPTAC DREAM Proteogenomics Challenge (Registration Now Open) | Office of Cancer Clinical Proteomics Research

Cancer.gov

Proteogenomics, integration of proteomics, genomics, and transcriptomics, is an emerging approach that promises to advance basic, translational and clinical research.  By combining genomic and proteomic information, leading scientists are gaining new insights due to a more complete and unified understanding of complex biological processes.

No Pass-No Play: Academic Requirements for Extracurricular Activities.

ERIC Educational Resources Information Center

Cromartie, Martha

1986-01-01

Discusses "no pass-no play" rules adopted by many state legislatures and local school districts that raise the academic standards students must meet before participating in extracurricular activities. Reviews two recent court challenges to the rules' constitutionality, focusing on due process, authority, and participation as a right or…

Truth in Testing: Arguments Examined.

ERIC Educational Resources Information Center

Burns, Daniel J.

1981-01-01

Costs and benefits of New York's Truth-in-Testing law are reviewed and related to constitutional issues and fairness to test-makers as well as test-takers. Besides matters of cost and test question availability, challenges to the legislation also involve issues of due process, equal protection, and infringement of existing copyright laws. (MSE)

Factors Influencing Science Content Accuracy in Elementary Inquiry Science Lessons

ERIC Educational Resources Information Center

Nowicki, Barbara L.; Sullivan-Watts, Barbara; Shim, Minsuk K.; Young, Betty; Pockalny, Robert

2013-01-01

Elementary teachers face increasing demands to engage children in authentic science process and argument while simultaneously preparing them with knowledge of science facts, vocabulary, and concepts. This reform is particularly challenging due to concerns that elementary teachers lack adequate science background to teach science accurately. This…

Extraction and recovery of phosphorus from pig manure using the quick wash process

USDA-ARS?s Scientific Manuscript database

Land disposal of manure is a challenging environmental problem in areas with intense confined pig production. Due to nutrient imbalance, manure applied to soil at optimal nitrogen rates for crop growth can promote soil phosphorus (P) surplus and potential pollution of water resources. Although manur...

The Legal Issues Surrounding the TAAS Case.

ERIC Educational Resources Information Center

Saucedo, Leticia M.

2000-01-01

Reviews legal claims made by the Mexican American Legal Defense and Educational Fund on behalf of plaintiffs challenging the Texas graduation requirement that students pass the Texas Assessment of Academic Skills. Discusses the requirement as a violation of minority students' equal protection and due process rights. Analyzes court actions and the…

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...

Intervention technologies for food safety on minimally processed produce:Perspectives on food-borne and plant pathogens

USDA-ARS?s Scientific Manuscript database

Produce contamination associated with enteric pathogens such Escherichia coli O157:H7, salmonella spp., Listeria monocytogenes, Shigella and others are significant challenges to food safety. This is due to the illnesses and economic impacts resulting from the outbreaks. Innovative technologies for i...

Organogel as an approach to protect omega-3 oils from oxidation

USDA-ARS?s Scientific Manuscript database

The global omega-3 oil market is steadily growing due to their beneficial health effects. However, it has been challenging to prevent oxidation of omega-3 oils since their polyunsaturated fats are very prone to oxidation during manufacturing processes, transportation, and storage. Organogels have ga...

Use of new scientific developments in regulatory risk assessments: challenges and opportunities.

PubMed

Tarazona, Jose V

2013-07-01

Since the 1990s, science based ecological risk assessments constitute an essential tool for supporting decision making in the regulatory context. Using the European REACH Regulation as example, this article presents the challenges and opportunities for new scientific developments within the area of chemical control and environmental protection. These challenges can be sorted out in 3 main related topics (sets). In the short term, the challenges are directly associated with the regulatory requirements, required for facilitating a scientifically sound implementation of the different obligations for industry and authorities. It is important to mention that although the actual tools are different due to the regulatory requirements, the basic needs are still the same as those addressed in the early 1990s: understanding the ecological relevance of the predicted effects, including the uncertainty, and facilitating the link with the socio-economic assessment. The second set of challenges covers the opportunities for getting an added value from the regulatory efforts. The information compiled through REACH registration and notification processes is analyzed as source for new integrative developments for assessing the combined chemical risk at the regional level. Finally, the article discusses the challenge of inverting the process and developing risk assessment methods focusing on the receptor, the individual or ecosystem, instead of on the stressor or source. These approaches were limited in the past due to the lack of information, but the identification and dissemination of standard information, including uses, manufacturing sites, physical-chemical, environmental, ecotoxicological, and toxicological properties as well as operational conditions and risk management measures for thousands of chemicals, combined by the knowledge gathered through large scale monitoring programs and spatial information systems is generating new opportunities. The challenge is liking predictions and measured data in an integral "-omic type" approach, considering collectively data from different sources and offering a complete assessment of the chemical risk of individuals and ecosystems, with new conceptual approaches that could be defined as "risk-omics based" paradigms and models. Copyright © 2013 SETAC.

Reconciling Scale Mismatch in Water Governance, Hydro-climatic Processes and Infrastructure Systems of Water Supply in Las Vegas

NASA Astrophysics Data System (ADS)

Garcia, M. E.; Alarcon, T.; Portney, K.; Islam, S.

2013-12-01

Water resource systems are a classic example of a common pool resource due to the high cost of exclusion and the subtractability of the resource; for common pool resources, the performance of governance systems primarily depends on how well matched the institutional arrangements and rules are to the biophysical conditions and social norms. Changes in water governance, hydro-climatic processes and infrastructure systems occur on disparate temporal and spatial scales. A key challenge is the gap between current climate change model resolution, and the spatial and temporal scale of urban water supply decisions. This gap will lead to inappropriate management policies if not mediated through a carefully crafted decision making process. Traditional decision support and planning methods (DSPM) such as classical decision analysis are not equipped to deal with a non-static climate. While emerging methods such as decision scaling, robust decision making and real options are designed to deal with a changing climate, governance systems have evolved under the assumption of a static climate and it is not clear if these methods are well suited to the existing governance regime. In our study, these questions are contextualized by examining an urban water utility that has made significant changes in policy to adapt to changing conditions: the Southern Nevada Water Authority (SNWA) which serves metropolitan Las Vegas. Like most desert cities, Las Vegas exists because of water; the artesian springs of the Las Vegas Valley once provided an ample water supply for Native Americans, ranchers and later a small railroad city. However, population growth has increased demands far beyond local supplies. The area now depends on the Colorado River for the majority of its water supply. Natural climate variability with periodic droughts has further challenged water providers; projected climate changes and further population growth will exacerbate these challenges. Las Vegas is selected as a case study due to the combined challenges of population growth and climate change, common in the arid west, and due its cooperative institutional response to these challenges, unprecedented in the arid west. To begin to disentangle this question we have analyzed the institutional arrangements and rules which govern water decision making in the Las Vegas Valley and evaluated the existing DSPM used by the SNWA and partner utilities. Presented here are the preliminary results from an ongoing project.

Meta-control of combustion performance with a data mining approach

NASA Astrophysics Data System (ADS)

Song, Zhe

Large scale combustion process is complex and proposes challenges of optimizing its performance. Traditional approaches based on thermal dynamics have limitations on finding optimal operational regions due to time-shift nature of the process. Recent advances in information technology enable people collect large volumes of process data easily and continuously. The collected process data contains rich information about the process and, to some extent, represents a digital copy of the process over time. Although large volumes of data exist in industrial combustion processes, they are not fully utilized to the level where the process can be optimized. Data mining is an emerging science which finds patterns or models from large data sets. It has found many successful applications in business marketing, medical and manufacturing domains The focus of this dissertation is on applying data mining to industrial combustion processes, and ultimately optimizing the combustion performance. However the philosophy, methods and frameworks discussed in this research can also be applied to other industrial processes. Optimizing an industrial combustion process has two major challenges. One is the underlying process model changes over time and obtaining an accurate process model is nontrivial. The other is that a process model with high fidelity is usually highly nonlinear, solving the optimization problem needs efficient heuristics. This dissertation is set to solve these two major challenges. The major contribution of this 4-year research is the data-driven solution to optimize the combustion process, where process model or knowledge is identified based on the process data, then optimization is executed by evolutionary algorithms to search for optimal operating regions.

Navy Successes and Challenges in Cr6+ Minimization

DTIC Science & Technology

2011-05-12

Authorization to Use Hexavalent Chromium. YES NO • Approval of alternatives by W/S PM and Corrosion SME designee. • Change technical/maintenance...Inorganic Coatings and Processes – Alternatives authorized for • Aluminum and magnesium anodizing • Hard Chrome Plating • Type II, Class 1A conversion...savings due to use of aluminum cathodes – Allows for consolidation of anodizing processes – Elimination of Hexavalent Chromium 80% 5% 14% 1% Type II

Current Challenges in Commercially Producing Biofuels from Lignocellulosic Biomass

PubMed Central

Balan, Venkatesh

2014-01-01

Biofuels that are produced from biobased materials are a good alternative to petroleum based fuels. They offer several benefits to society and the environment. Producing second generation biofuels is even more challenging than producing first generation biofuels due the complexity of the biomass and issues related to producing, harvesting, and transporting less dense biomass to centralized biorefineries. In addition to this logistic challenge, other challenges with respect to processing steps in converting biomass to liquid transportation fuel like pretreatment, hydrolysis, microbial fermentation, and fuel separation still exist and are discussed in this review. The possible coproducts that could be produced in the biorefinery and their importance to reduce the processing cost of biofuel are discussed. About $1 billion was spent in the year 2012 by the government agencies in US to meet the mandate to replace 30% existing liquid transportation fuels by 2022 which is 36 billion gallons/year. Other countries in the world have set their own targets to replace petroleum fuel by biofuels. Because of the challenges listed in this review and lack of government policies to create the demand for biofuels, it may take more time for the lignocellulosic biofuels to hit the market place than previously projected. PMID:25937989

United States: challenges filed to anti-prostitution pledge requirement.

PubMed

Schleifer, Rebecca

2005-12-01

Two separate lawsuits were filed recently in US federal courts challenging a provision of US law requiring that non-governmental organizations have a policy "explicitly opposing prostitution" as a condition of receiving funding under the United States Leadership against HIV/AIDS, Tuberculosis, and Malaria Act of 2003 (US Global AIDS Act). US-based plaintiffs in both cases argue that the anti-prostitution pledge requirement in the Act violates US Constitutional guarantees of free speech and due process, and undermines proven, effective efforts to fight HIV/AIDS among sex workers.

Co-Producing Accessible Climate Knowledge: Case Study of a Scientific Challenge

NASA Astrophysics Data System (ADS)

Bourqui, M.; Charriere, M. K. M.; Bolduc, C.

2016-12-01

This talk presents the process of and the lessons learned from a scientific challenge where climate scientists re-framed their research for the general public in interaction with members of the general public. This challenge was organized by Climanosco in the context of its launch in the fall 2015 and is due to end in September 2016. It led to the publication of 11 articles from scientific authors spanning 7 countries and engaged the participation of 24 members of the general public. The process of interaction between scientists and members of the general public took place along an extended peer-review process which included on-line community discussions and non-scientific review reports. Details of this interaction, as perceived by the participants and evaluated by a survey, will be discussed in this talk. On the longer term this co-production of accessible climate knowledge, which represents the main goal of the non-profit association Climanosco, is meant to serve as a reliable, research-based source, the decision makers but also the journalists, teachers and communities around the world.

The Benefits and Challenges of Preconsent in a Multisite, Pediatric Sickle Cell Intervention Trial.

PubMed

Nimmer, Mark; Czachor, Jason; Turner, Laura; Thomas, Bobbe; Woodford, Ashley L; Carpenter, Karli; Gonzalez, Victor; Liem, Robert I; Ellison, Angela; Casper, T Charles; Brousseau, David C

2016-09-01

Enrollment of patients in sickle cell intervention trials has been challenging due to difficulty in obtaining consent from a legal guardian and lack of collaboration between emergency medicine and hematology. We utilized education and preconsent in a pediatric multisite sickle cell intervention trial to overcome these challenges. Overall, 48 patients were enrolled after being preconsented. Variable Institutional Review Board policies related to preconsent validity and its allowable duration decreased the advantages of preconsent at some sites. The utility of preconsent for future intervention trials largely depends on local Institutional Review Board policies. Preeducation may also benefit the consent process, regardless of site differences. © 2016 Wiley Periodicals, Inc.

A Simple Text File for Curing Rainbow Blindness

NASA Technical Reports Server (NTRS)

Krylo, Robert; Tomlin, Marilyn; Seager, Michael

2008-01-01

This slide presentation reviews the use of a simple text file to work with large, multi-component thermal models that present a post-processing challenge. This complexity is due to temperatures for many components, with varying requirements, need to be examined and that false color temperature maps, or rainbows, provide a qualitative assessment of results.

Preparing Marketing for the Future: Strategic Marketing Challenges for Continuing Education

ERIC Educational Resources Information Center

Fong, James

2013-01-01

Today's programs and delivery methods in continuing education for the adult student are evolving due to changing needs, competition, and new markets and technologies. The marketing infrastructure, including staffing, budgeting, and processes such as customer relationship marketing and market research, must be in alignment with changing needs.

Is It Not Now?: School Counselors' Training in Tanzania Secondary Schools

ERIC Educational Resources Information Center

Mabula, Nkuba; Edna, Kyaruzi

2015-01-01

Counseling is currently becoming a necessary service for school learners in the developing world, this is due to fact that, the challenges facing learners in their learning process results into both internalizing and externalizing problems which affect student's learning in terms of social, psychology and academic. This paper explores the status…

A Design Case of Scaffolding Hybrid/Online Student-Centered Learning with Multimedia

ERIC Educational Resources Information Center

Hsiao, E-Ling; Mikolaj, Peter; Shih, Ya-Ting

2017-01-01

Implementing student-centered learning in hybrid/online settings is very challenging due to the physical separation of instructor and students. This article discusses the need for instructors to provide scaffolds and multimedia modules to facilitate knowledge construction in the student-centered learning process. To offer students solid learning…

Teacher Collaborative Curriculum Design in Technical Vocational Colleges: A Strategy for Maintaining Curriculum Consistency?

ERIC Educational Resources Information Center

Albashiry, Nabeel M.; Voogt, Joke M.; Pieters, Jules M.

2015-01-01

The Technical Vocational Education and Training (TVET) curriculum requires continuous renewal and constant involvement of stakeholders in the redesign process. Due to a lack of curriculum design expertise, TVET institutions in developing contexts encounter challenges maintaining and advancing the quality and relevance of their programmes to the…

Detecting Plagiarism in MS Access Assignments

ERIC Educational Resources Information Center

Singh, Anil

2013-01-01

Assurance of individual effort from students in computer-based assignments is a challenge. Due to digitization, students can easily use a copy of their friend's work and submit it as their own. Plagiarism in assignments puts students who cheat at par with those who work honestly and this compromises the learning evaluation process. Using a…

Professional Development to Improve Accommodations Decisions--A Review of the Literature. Synthesis Report 84

ERIC Educational Resources Information Center

Hodgson, Jennifer R.; Lazarus, Sheryl S.; Thurlow, Martha L.

2011-01-01

Teachers play an important role in making decisions about students' accommodations for instruction and assessment. Although teachers are a significant part of the decision-making process, "gaps" in teachers' accommodations knowledge are well documented. Some of these gaps may be due to challenges in providing teacher professional…

Evaluating the SWAT model for a low-gradient forested watershed in coastal South Carolina

Treesearch

D.M. Amatya; M.K. Jha.

2011-01-01

Modeling the hydrology of low�]gradient forested watersheds on shallow, poorly drained soils of the coastal plain is a challenging task due to complexities in watershed delineation, microtopography, evapotranspiration, runoff generation processes and pathways including flooding and submergence caused by tropical storms, and complexity of vegetation species....

Cultural Considerations for Twice-Exceptional Children from Asian Families

ERIC Educational Resources Information Center

Park, Soeun

2015-01-01

Since the term twice-exceptional has been entered to the field of gifted education, many studies have investigated the population of students who possess both giftedness and disabilities. It has been shown that there are some challenges to recognizing twice-exceptional children due to current screening and identification process. For this reason,…

Reduced cost and improved figure of sapphire optical components

NASA Astrophysics Data System (ADS)

Walters, Mark; Bartlett, Kevin; Brophy, Matthew R.; DeGroote Nelson, Jessica; Medicus, Kate

2015-10-01

Sapphire presents many challenges to optical manufacturers due to its high hardness and anisotropic properties. Long lead times and high prices are the typical result of such challenges. The cost of even a simple 'grind and shine' process can be prohibitive. The high precision surfaces required by optical sensor applications further exacerbate the challenge of processing sapphire thereby increasing cost further. Optimax has demonstrated a production process for such windows that delivers over 50% time reduction as compared to traditional manufacturing processes for sapphire, while producing windows with less than 1/5 wave rms figure error. Optimax's sapphire production process achieves significant improvement in cost by implementation of a controlled grinding process to present the best possible surface to the polishing equipment. Following the grinding process is a polishing process taking advantage of chemical interactions between slurry and substrate to deliver excellent removal rates and surface finish. Through experiments, the mechanics of the polishing process were also optimized to produce excellent optical figure. In addition to reducing the cost of producing large sapphire sensor windows, the grinding and polishing technology Optimax has developed aids in producing spherical sapphire components to better figure quality. In addition to reducing the cost of producing large sapphire sensor windows, the grinding and polishing technology Optimax has developed aids in producing spherical sapphire components to better figure quality. Through specially developed polishing slurries, the peak-to-valley figure error of spherical sapphire parts is reduced by over 80%.

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

Kazyak, Eric; Chen, Kuan-Hung; Wood, Kevin N.

Lithium solid electrolytes are a promising platform for achieving high energy density, long-lasting, and safe rechargeable batteries, which could have widespread societal impact. In particular, the ceramic oxide garnet Li7La3Zr2O12 (LLZO) has been shown to be a promising electrolyte due to its stability and high ionic conductivity. Two major challenges for commercialization are manufacturing of thin layers and creating stable, low-impedance, interfaces with both anode and cathode materials. Atomic Layer Deposition (ALD) has recently been shown as a potential method for depositing both solid electrolytes and interfacial layers to improve the stability and performance at electrode-electrolyte interfaces in battery systems.more » Herein we present the first reported ALD process for LLZO, demonstrating the ability to tune composition within the amorphous film and anneal to achieve the desired cubic garnet phase. Formation of the cubic phase was observed at temperatures as low as 555°C, significantly lower than is required for bulk processing. Additionally, challenges associated with achieving a dense garnet phase due to substrate reactivity, morphology changes and Li loss under the necessary high temperature annealing are quantified via in situ synchrotron diffraction.« less

Young Stellar Objects from Soft to Hard X-rays

NASA Astrophysics Data System (ADS)

Güdel, Manuel

2009-05-01

Magnetically active stars are the sites of efficient particle acceleration and plasma heating, processes that have been studied in detail in the solar corona. Investigation of such processes in young stellar objects is much more challenging due to various absorption processes. There is, however, evidence for violent magnetic energy release in very young stellar objects. The impact on young stellar environments (e.g., circumstellar disk heating and ionization, operation of chemical networks, photoevaporation) may be substantial. Hard X-ray devices like those carried on Simbol-X will establish a basis for detailed studies of these processes.

Progress in Operational Analysis of Launch Vehicles in Nonstationary Flight

NASA Technical Reports Server (NTRS)

James, George; Kaouk, Mo; Cao, Timothy

2013-01-01

This paper presents recent results in an ongoing effort to understand and develop techniques to process launch vehicle data, which is extremely challenging for modal parameter identification. The primary source of difficulty is due to the nonstationary nature of the situation. The system is changing, the environment is not steady, and there is an active control system operating. Hence, the primary tool for producing clean operational results (significant data lengths and data averaging) is not available to the user. This work reported herein uses a correlation-based two step operational modal analysis approach to process the relevant data sets for understanding and development of processes. A significant drawback for such processing of short time histories is a series of beating phenomena due to the inability to average out random modal excitations. A recursive correlation process coupled to a new convergence metric (designed to mitigate the beating phenomena) is the object of this study. It has been found in limited studies that this process creates clean modal frequency estimates but numerically alters the damping.

The development of additive manufacturing technique for nickel-base alloys: A review

NASA Astrophysics Data System (ADS)

Zadi-Maad, Ahmad; Basuki, Arif

2018-04-01

Nickel-base alloys are an attractive alloy due to its excellent mechanical properties, a high resistance to creep deformation, corrosion, and oxidation. However, it is a hard task to control performance when casting or forging for this material. In recent years, additive manufacturing (AM) process has been implemented to replace the conventional directional solidification process for the production of nickel-base alloys. Due to its potentially lower cost and flexibility manufacturing process, AM is considered as a substitute technique for the existing. This paper provides a comprehensive review of the previous work related to the AM techniques for Ni-base alloys while highlighting current challenges and methods to solving them. The properties of conventionally manufactured Ni-base alloys are also compared with the AM fabricated alloys. The mechanical properties obtained from tension, hardness and fatigue test are included, along with discussions of the effect of post-treatment process. Recommendations for further work are also provided.

On the use of fractional order PK-PD models

NASA Astrophysics Data System (ADS)

Ionescu, Clara; Copot, Dana

2017-01-01

Quantifying and controlling depth of anesthesia is a challenging process due to lack of measurement technology for direct effects of drug supply into the body. Efforts are being made to develop new sensor techniques and new horizons are explored for modeling this intricate process. This paper introduces emerging tools available on the ‘engineering market’ imported from the area of fractional calculus. A novel interpretation of the classical drug-effect curve is given, enabling linear control. This enables broadening the horizon of signal processing and control techniques and suggests future research lines.

Myoelectric signal processing for control of powered limb prostheses.

PubMed

Parker, P; Englehart, K; Hudgins, B

2006-12-01

Progress in myoelectric control technology has over the years been incremental, due in part to the alternating focus of the R&D between control methodology and device hardware. The technology has over the past 50 years or so moved from single muscle control of a single prosthesis function to muscle group activity control of multifunction prostheses. Central to these changes have been developments in the means of extracting information from the myoelectric signal. This paper gives an overview of the myoelectric signal processing challenge, a brief look at the challenge from an historical perspective, the state-of-the-art in myoelectric signal processing for prosthesis control, and an indication of where this field is heading. The paper demonstrates that considerable progress has been made in providing clients with useful and reliable myoelectric communication channels, and that exciting work and developments are on the horizon.

Review of enhanced processes for anaerobic digestion treatment of sewage sludge

NASA Astrophysics Data System (ADS)

Liu, Xinyuan; Han, Zeyu; Yang, Jie; Ye, Tianyi; Yang, Fang; Wu, Nan; Bao, Zhenbo

2018-02-01

Great amount of sewage sludge had been produced each year, which led to serious environmental pollution. Many new technologies had been developed recently, but they were hard to be applied in large scales. As one of the traditional technologies, anaerobic fermentation process was capable of obtaining bioenergy by biogas production under the functions of microbes. However, the anaerobic process is facing new challenges due to the low fermentation efficiency caused by the characteristics of sewage sludge itself. In order to improve the energy yield, the enhancement technologies including sewage sludge pretreatment process, co-digestion process, high-solid digestion process and two-stage fermentation process were widely studied in the literatures, which were introduced in this article.

Integrated Data Modeling and Simulation on the Joint Polar Satellite System Program

NASA Technical Reports Server (NTRS)

Roberts, Christopher J.; Boyce, Leslye; Smith, Gary; Li, Angela; Barrett, Larry

2012-01-01

The Joint Polar Satellite System is a modern, large-scale, complex, multi-mission aerospace program, and presents a variety of design, testing and operational challenges due to: (1) System Scope: multi-mission coordination, role, responsibility and accountability challenges stemming from porous/ill-defined system and organizational boundaries (including foreign policy interactions) (2) Degree of Concurrency: design, implementation, integration, verification and operation occurring simultaneously, at multiple scales in the system hierarchy (3) Multi-Decadal Lifecycle: technical obsolesce, reliability and sustainment concerns, including those related to organizational and industrial base. Additionally, these systems tend to become embedded in the broader societal infrastructure, resulting in new system stakeholders with perhaps different preferences (4) Barriers to Effective Communications: process and cultural issues that emerge due to geographic dispersion and as one spans boundaries including gov./contractor, NASA/Other USG, and international relationships.

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

Competence to proceed in SVP commitment hearings: Irrelevant or fundamental due process right?

PubMed

Fanniff, Amanda M; Otto, Randy K; Petrila, John

2010-01-01

Sexually Violent Predator (SVP) civil commitment, intended to incapacitate offenders and protect the public, has been implemented in 21 jurisdictions. While respondents in traditional civil commitment proceedings need not be competent to proceed, SVP commitment may present a greater deprivation of liberty and therefore greater procedural protections may be merited. Statutes and case law regarding competence in this context address two issues: competence to challenge unproven sexual offense allegations and competence to participate in the SVP commitment process. Of the 14 states that have addressed the issue, one concluded that respondents must be competent to challenge unproven allegations and one concluded that all SVP respondents must be competent to participate in the commitment process. Differences between SVP and traditional civil commitment, the rationale underlying the competence requirement, and decisions regarding competence in SVP commitment are reviewed to inform debate regarding whether SVP respondents must be competent to proceed with the commitment process. Copyright © 2010 John Wiley & Sons, Ltd.

THz spectroscopy: An emerging technology for pharmaceutical development and pharmaceutical Process Analytical Technology (PAT) applications

NASA Astrophysics Data System (ADS)

Wu, Huiquan; Khan, Mansoor

2012-08-01

As an emerging technology, THz spectroscopy has gained increasing attention in the pharmaceutical area during the last decade. This attention is due to the fact that (1) it provides a promising alternative approach for in-depth understanding of both intermolecular interaction among pharmaceutical molecules and pharmaceutical product quality attributes; (2) it provides a promising alternative approach for enhanced process understanding of certain pharmaceutical manufacturing processes; and (3) the FDA pharmaceutical quality initiatives, most noticeably, the Process Analytical Technology (PAT) initiative. In this work, the current status and progress made so far on using THz spectroscopy for pharmaceutical development and pharmaceutical PAT applications are reviewed. In the spirit of demonstrating the utility of first principles modeling approach for addressing model validation challenge and reducing unnecessary model validation "burden" for facilitating THz pharmaceutical PAT applications, two scientific case studies based on published THz spectroscopy measurement results are created and discussed. Furthermore, other technical challenges and opportunities associated with adapting THz spectroscopy as a pharmaceutical PAT tool are highlighted.

Bioengineering Solutions for Manufacturing Challenges in CAR T Cells

PubMed Central

Piscopo, Nicole J.; Mueller, Katherine P.; Das, Amritava; Hematti, Peiman; Murphy, William L.; Palecek, Sean P.; Capitini, Christian M.

2017-01-01

The next generation of therapeutic products to be approved for the clinic is anticipated to be cell therapies, termed “living drugs” for their capacity to dynamically and temporally respond to changes during their production ex vivo and after their administration in vivo. Genetically engineered chimeric antigen receptor (CAR) T cells have rapidly developed into powerful tools to harness the power of immune system manipulation against cancer. Regulatory agencies are beginning to approve CAR T cell therapies due to their striking efficacy in treating some hematological malignancies. However, the engineering and manufacturing of such cells remains a challenge for widespread adoption of this technology. Bioengineering approaches including biomaterials, synthetic biology, metabolic engineering, process control and automation, and in vitro disease modeling could offer promising methods to overcome some of these challenges. Here, we describe the manufacturing process of CAR T cells, highlighting potential roles for bioengineers to partner with biologists and clinicians to advance the manufacture of these complex cellular products under rigorous regulatory and quality control. PMID:28840981

Challenges ahead for mass spectrometry and proteomics applications in epigenetics.

PubMed

Kessler, Benedikt M

2010-02-01

Inheritance of biological information to future generations depends on the replication of DNA and the Mendelian principle of distribution of genes. In addition, external and environmental factors can influence traits that can be propagated to offspring, but the molecular details of this are only beginning to be understood. The discoveries of DNA methylation and post-translational modifications on chromatin and histones provided entry points for regulating gene expression, an area now defined as epigenetics and epigenomics. Mass spectrometry turned out to be instrumental in uncovering molecular details involved in these processes. The central role of histone post-translational modifications in epigenetics related biological processes has revitalized mass spectrometry based investigations. In this special report, current approaches and future challenges that lay ahead due to the enormous complexity are discussed.

Cancer in the Solomon Islands.

PubMed

Martiniuk, Alexandra; Jagilli, Rooney; Natuzzi, Eileen; Ilopitu, John Wesley; Oipata, Meltus; Christie, Annie-Marie; Korini, Jefferey; Vujovich-Dunn, Cassandra; Yu, William

2017-10-01

The Solomon Islands, with a population of 550,000, has significant challenges in addressing non-communicable diseases, including cancer, in the face of significant economic, cultural, general awareness and health system challenges. To summarise the existing knowledge regarding cancer in the Solomon Islands, to gather new data and make recommendations. A literature review was undertaken and cancer data from the National Referral Hospital, Honiara were analysed and are presented. Key stakeholders were interviewed for their perspectives including areas to target for ongoing, incremental improvements. Last, a health services audit for cancer using the WHO SARA tool was undertaken. Breast and cervical cancer remain the first and second most commonly identified cancers in the Solomon Islands. The Solomons cancer registry is hospital based and suffers from incomplete data collection due to its passive nature, lack of resources for data entry and processing resulting in weak data which is rarely used for decision-making. The health system audit revealed system and individual reasons for delayed diagnosis or lack of cancer treatment or palliation in the Solomon Islands. Reasons included lack of patient knowledge regarding symptoms, late referrals to the National Referral Hospital and inability of health care workers to detect cancers either due to lack of skills to do so, or lack of diagnostic capabilities, and an overall lack of access to any health care, due to geographical barriers and overall national economic fragility. The Solomon Islands is challenged in preventing, diagnosing, treating and palliating cancer. Stakeholders recommend establishing specialty expertise (in the form of a cancer unit), improved registry processes and increased collaboration between the sole tertiary hospital nationwide and other Solomon health services as important targets for incremental improvement. Copyright © 2017. Published by Elsevier Ltd.

Automatic Domain Adaptation of Word Sense Disambiguation Based on Sublanguage Semantic Schemata Applied to Clinical Narrative

ERIC Educational Resources Information Center

Patterson, Olga

2012-01-01

Domain adaptation of natural language processing systems is challenging because it requires human expertise. While manual effort is effective in creating a high quality knowledge base, it is expensive and time consuming. Clinical text adds another layer of complexity to the task due to privacy and confidentiality restrictions that hinder the…

Transition Processes from College to Career.

ERIC Educational Resources Information Center

Hettich, Paul

The transition from college to career is one of the most challenging jobs an individual will experience. This is particularly true for students who have limited work experience. The fact that 50-80% of new college graduates leave their first job within three years may be due to poor career planning and problems inherent in the college-to-work…

Taylor-Aris Dispersion: An Explicit Example for Understanding Multiscale Analysis via Volume Averaging

ERIC Educational Resources Information Center

Wood, Brian D.

2009-01-01

Although the multiscale structure of many important processes in engineering is becoming more widely acknowledged, making this connection in the classroom is a difficult task. This is due in part because the concept of multiscale structure itself is challenging and it requires the students to develop new conceptual pictures of physical systems,…

Personal Inquiry Learning Trajectories in Geography: Technological Support across Contexts

ERIC Educational Resources Information Center

Kerawalla, Lucinda; Littleton, Karen; Scanlon, Eileen; Jones, Ann; Gaved, Mark; Collins, Trevor; Mulholland, Paul; Blake, Canan; Clough, Gill; Conole, Gráinne; Petrou, Marilena

2013-01-01

Student engagement in the design and implementation of inquiries is an effective way for them to learn about the inquiry process and the domain being studied. However, inquiry learning in geography can be challenging for teachers and students due to the complexity of scientific inquiry and the diversity of pupils' and teachers' knowledge and…

A review of the challenges and opportunities in estimating above ground forest biomass using tree-level models

Treesearch

Hailemariam Temesgen; David Affleck; Krishna Poudel; Andrew Gray; John Sessions

2015-01-01

Accurate biomass measurements and analyses are critical components in quantifying carbon stocks and sequestration rates, assessing potential impacts due to climate change, locating bio-energy processing plants, and mapping and planning fuel treatments. To this end, biomass equations will remain a key component of future carbon measurements and estimation. As...

Critical Approaches to Financial Delegation in Public Education in Post-Communist Romania

ERIC Educational Resources Information Center

Popescu, Ana-Cristina

2011-01-01

The article focuses on tracking financial delegation (introduced nationally in January 2010) as part of the broader process of education restructuring and decentralisation in post-communist Romania. The aim is to critically pinpoint some of the challenges specific to the Romanian context, such as the multitude of policies and legislation (due to…

Potato processing scenario in India: Industrial constraints, future projections, challenges ahead and remedies - A review.

PubMed

Marwaha, R S; Pandey, S K; Kumar, Dinesh; Singh, S V; Kumar, Parveen

2010-03-01

Indian potato (Solanum tuberosum L.) processing industry has emerged fast due to economic liberalization coupled with growing urbanization, expanding market options and development of indegenous processing varieties. India's first potato processing varieties 'Kufri Chipsona-1' and 'Kufri Chipsona-2' were developed in 1998, followed by an improved processing variety 'Kufri Chipsona-3' in 2005 for the Indian plains and first chipping variety 'Kufri Himsona' for the hills. These varieties have >21% tuber dry matter content, contain low reducing sugars (<0.1% on fresh wt) and are most suitable for producing chips, French fries and dehydrated products. The availability of these varieties and standardization of storage techniques for processing potatoes at 10-12°C with sprout suppressant isopropyl N-(3-chlorophenyl) carbamate have revolutionized the processing scenario within a short span of 10 years. Currently about 4% of total potato produce is being processed in organized and unorganized sector. Potato processing industry mainly comprises 4 segments: potato chips, French fries, potato flakes/powder and other processed products. However, potato chips still continue to be the most popular processed product. The major challenge facing the industries lies in arranging round the year supply of processing varieties at reasonable price for their uninterrupted operation, besides several others which have been discussed at length and addressed with concrete solutions.

Reference software implementation for GIFTS ground data processing

NASA Astrophysics Data System (ADS)

Garcia, R. K.; Howell, H. B.; Knuteson, R. O.; Martin, G. D.; Olson, E. R.; Smuga-Otto, M. J.

2006-08-01

Future satellite weather instruments such as high spectral resolution imaging interferometers pose a challenge to the atmospheric science and software development communities due to the immense data volumes they will generate. An open-source, scalable reference software implementation demonstrating the calibration of radiance products from an imaging interferometer, the Geosynchronous Imaging Fourier Transform Spectrometer1 (GIFTS), is presented. This paper covers essential design principles laid out in summary system diagrams, lessons learned during implementation and preliminary test results from the GIFTS Information Processing System (GIPS) prototype.

Towards an Integrated QR Code Biosensor: Light-Driven Sample Acquisition and Bacterial Cellulose Paper Substrate.

PubMed

Yuan, Mingquan; Jiang, Qisheng; Liu, Keng-Ku; Singamaneni, Srikanth; Chakrabartty, Shantanu

2018-06-01

This paper addresses two key challenges toward an integrated forward error-correcting biosensor based on our previously reported self-assembled quick-response (QR) code. The first challenge involves the choice of the paper substrate for printing and self-assembling the QR code. We have compared four different substrates that includes regular printing paper, Whatman filter paper, nitrocellulose membrane and lab synthesized bacterial cellulose. We report that out of the four substrates bacterial cellulose outperforms the others in terms of probe (gold nanorods) and ink retention capability. The second challenge involves remote activation of the analyte sampling and the QR code self-assembly process. In this paper, we use light as a trigger signal and a graphite layer as a light-absorbing material. The resulting change in temperature due to infrared absorption leads to a temperature gradient that then exerts a diffusive force driving the analyte toward the regions of self-assembly. The working principle has been verified in this paper using assembled biosensor prototypes where we demonstrate higher sample flow rate due to light induced thermal gradients.

Combating the Reliability Challenge of GPU Register File at Low Supply Voltage

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

Tan, Jingweijia; Song, Shuaiwen; Yan, Kaige

Supply voltage reduction is an effective approach to significantly reduce GPU energy consumption. As the largest on-chip storage structure, the GPU register file becomes the reliability hotspot that prevents further supply voltage reduction below the safe limit (Vmin) due to process variation effects. This work addresses the reliability challenge of the GPU register file at low supply voltages, which is an essential first step for aggressive supply voltage reduction of the entire GPU chip. We propose GR-Guard, an architectural solution that leverages long register dead time to enable reliable operations from unreliable register file at low voltages.

BNL 56 MHz HOM damper prototype fabrication at JLAB

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

Huque, N.; McIntyre, G.; Daly, E. F.

A prototype Higher-Order Mode (HOM) Damper was fabricated at JLab for the Relativistic Heavy-Ion Collider’s (RHIC) 56 MHz cavity at Brookhaven National Laboratory (BNL). Primarily constructed from high RRR Niobium and Sapphire, the coaxial damper presented significant challenges in electron-beam welding (EBW), brazing and machining via acid etching. The results of the prototype operation brought about changes in the damper design, due to overheating braze alloys and possible multi-pacting. Five production HOM dampers are currently being fabricated at JLab. This paper outlines the challenges faced in the fabrication process, and the solutions put in place.

BNL 56 MHz HOM Damper Prototype Fabrication at JLab

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

Huque, Naeem A.; Daly, Edward F.; Clemens, William A.

A prototype Higher-Order Mode (HOM) Damper was fabricated at JLab for the Relativistic Heavy-Ion Collider's (RHIC) 56 MHz cavity at Brookhaven National Laboratory (BNL). Primarily constructed from high RRR Niobium and Sapphire, the coaxial damper presented significant challenges in electron-beam welding (EBW), brazing and machining via acid etching. The results of the prototype operation brought about changes in the damper design, due to overheating braze alloys and possible multi-pacting. Five production HOM dampers are currently being fabricated at JLab. This paper outlines the challenges faced in the fabrication process, and the solutions put in place.

Additive manufacturing in production: challenges and opportunities

NASA Astrophysics Data System (ADS)

Ahuja, Bhrigu; Karg, Michael; Schmidt, Michael

2015-03-01

Additive manufacturing, characterized by its inherent layer by layer fabrication methodology has been coined by many as the latest revolution in the manufacturing industry. Due to its diversification of Materials, processes, system technology and applications, Additive Manufacturing has been synonymized with terminology such as Rapid prototyping, 3D printing, free-form fabrication, Additive Layer Manufacturing, etc. A huge media and public interest in the technology has led to an innovative attempt of exploring the technology for applications beyond the scope of the traditional engineering industry. Nevertheless, it is believed that a critical factor for the long-term success of Additive Manufacturing would be its ability to fulfill the requirements defined by the traditional manufacturing industry. A parallel development in market trends and product requirements has also lead to a wider scope of opportunities for Additive Manufacturing. The presented paper discusses some of the key challenges which are critical to ensure that Additive Manufacturing is truly accepted as a mainstream production technology in the industry. These challenges would highlight on various aspects of production such as product requirements, process management, data management, intellectual property, work flow management, quality assurance, resource planning, etc. In Addition, changing market trends such as product life cycle, mass customization, sustainability, environmental impact and localized production will form the foundation for the follow up discussion on the current limitations and the corresponding research opportunities. A discussion on ongoing research to address these challenges would include topics like process monitoring, design complexity, process standardization, multi-material and hybrid fabrication, new material development, etc.

Current Challenges in Commercially Producing Biofuels from Lignocellulosic Biomass

DOE PAGES

Balan, Venkatesh

2014-01-01

Biofuels that are produced from biobased materials are a good alternative to petroleum based fuels. They offer several benefits to society and the environment. Producing second generation biofuels is even more challenging than producing first generation biofuels due the complexity of the biomass and issues related to producing, harvesting, and transporting less dense biomass to centralized biorefineries. In addition to this logistic challenge, other challenges with respect to processing steps in converting biomass to liquid transportation fuel like pretreatment, hydrolysis, microbial fermentation, and fuel separation still exist and are discussed in this review. The possible coproducts that could be producedmore » in the biorefinery and their importance to reduce the processing cost of biofuel are discussed. About $1 billion was spent in the year 2012 by the government agencies in US to meet the mandate to replace 30% existing liquid transportation fuels by 2022 which is 36 billion gallons/year. Other countries in the world have set their own targets to replace petroleum fuel by biofuels. Because of the challenges listed in this review and lack of government policies to create the demand for biofuels, it may take more time for the lignocellulosic biofuels to hit the market place than previously projected.« less

Reverse osmosis integrity monitoring in water reuse: The challenge to verify virus removal - A review.

PubMed

Pype, Marie-Laure; Lawrence, Michael G; Keller, Jurg; Gernjak, Wolfgang

2016-07-01

A reverse osmosis (RO) process is often included in the treatment train to produce high quality reuse water from treated effluent for potable purposes because of its high removal efficiency for salinity and many inorganic and organic contaminants, and importantly, it also provides an excellent barrier for pathogens. In order to ensure the continued protection of public health from pathogen contamination, monitoring RO process integrity is necessary. Due to their small sizes, viruses are the most difficult class of pathogens to be removed in physical separation processes and therefore often considered the most challenging pathogen to monitor. To-date, there is a gap between the current log credit assigned to this process (determined by integrity testing approved by regulators) and its actual log removal capability as proven in a variety of laboratory and pilot studies. Hence, there is a challenge to establish a methodology that more closely links to the theoretical performance. In this review, after introducing the notion of risk management in water reuse, we provide an overview of existing and potentially new RO integrity monitoring techniques, highlight their strengths and drawbacks, and debate their applicability to full-scale treatment plants, which open to future research opportunities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Towards Compensation Correctness in Interactive Systems

NASA Astrophysics Data System (ADS)

Vaz, Cátia; Ferreira, Carla

One fundamental idea of service-oriented computing is that applications should be developed by composing already available services. Due to the long running nature of service interactions, a main challenge in service composition is ensuring correctness of failure recovery. In this paper, we use a process calculus suitable for modelling long running transactions with a recovery mechanism based on compensations. Within this setting, we discuss and formally state correctness criteria for compensable processes compositions, assuming that each process is correct with respect to failure recovery. Under our theory, we formally interpret self-healing compositions, that can detect and recover from failures, as correct compositions of compensable processes.

Printed batteries and conductive patterns in technical textiles

NASA Astrophysics Data System (ADS)

Willert, Andreas; Meuser, Carmen; Baumann, Reinhard R.

2018-05-01

Various applications of functional devices need a tailored and reliable supply of electrical energy. Batteries are electrochemical systems that deliver energy for functional devices and applications. Due to the common use, several rigid types of batteries have been standardized. To fully integrate the battery into a product that is bendable, free in geometry and less than 1 mm thick, printing of power adaptable batteries is a challenging area of research. Therefore, the well-known zinc-manganese system, which is very promising due to its environmental sustainability and its simplicity, has been used to manufacture battery solutions on a new kind of substrate: technical textiles. Another challenge is the deposition of conductive patterns. At present, embroidery with metallic yarn is the only possibility to provide conducting paths on technical textiles, a time-consuming and elaborate process. Screen printed conductive pathways will generate a new momentum in the manufacturing of conductivity on textiles.

Collaboration in Global Software Engineering Based on Process Description Integration

NASA Astrophysics Data System (ADS)

Klein, Harald; Rausch, Andreas; Fischer, Edward

Globalization is one of the big trends in software development. Development projects need a variety of different resources with appropriate expert knowledge to be successful. More and more of these resources are nowadays obtained from specialized organizations and countries all over the world, varying in development approaches, processes, and culture. As seen with early outsourcing attempts, collaboration may fail due to these differences. Hence, the major challenge in global software engineering is to streamline collaborating organizations towards a successful conjoint development. Based on typical collaboration scenarios, this paper presents a structured approach to integrate processes in a comprehensible way.

Conformational Transitions in Molecular Systems

NASA Astrophysics Data System (ADS)

Bachmann, M.; Janke, W.

2008-11-01

Proteins are the "work horses" in biological systems. In almost all functions specific proteins are involved. They control molecular transport processes, stabilize the cell structure, enzymatically catalyze chemical reactions; others act as molecular motors in the complex machinery of molecular synthetization processes. Due to their significance, misfolds and malfunctions of proteins typically entail disastrous diseases, such as Alzheimer's disease and bovine spongiform encephalopathy (BSE). Therefore, the understanding of the trinity of amino acid composition, geometric structure, and biological function is one of the most essential challenges for the natural sciences. Here, we glance at conformational transitions accompanying the structure formation in protein folding processes.

Onboard Classification of Hyperspectral Data on the Earth Observing One Mission

NASA Technical Reports Server (NTRS)

Chien, Steve; Tran, Daniel; Schaffer, Steve; Rabideau, Gregg; Davies, Ashley Gerard; Doggett, Thomas; Greeley, Ronald; Ip, Felipe; Baker, Victor; Doubleday, Joshua;

Identifying challenges in project consultants engagement practices

NASA Astrophysics Data System (ADS)

Shariffuddin, Nadia Alina Amir; Abidin, Nazirah Zainul

2017-10-01

Construction projects, green or conventional, involve multi-faceted disciplines engaged with the goal of delivering products i.e. building, infrastructure etc. at the best quality within stipulated budgets. For green projects, additional attention is added for environmental quality. Due to the various responsibilities and liabilities involved as well as the complexity of the construction process itself, formal engagement of multi-disciplinary professionals i.e. project consultants is required in any construction project. Poor selection of project consultants will lead to a multitude of complications resulting in delay, cost escalation, conflicts and poor quality. This paper explores the challenges that occur during the engagement of project consultants in a green project. As the engagement decision involves developers and architects, these two groups of respondents with green project backgrounds were approached qualitatively using interview technique. The challenges identified are limited experience and knowledge, consultants' fee vs. quality, green complexity, conflicts of interest, clients' extended expectation and less demand in green projects. The construction shifts to green project demands engagement of project consultants with added skills. It is expected that through the identification of challenges, better management and administration can be created which would give impact to the overall process of engagement in green projects.

Design of a framework for modeling, integration and simulation of physiological models.

PubMed

Erson, E Zeynep; Cavuşoğlu, M Cenk

2012-09-01

Multiscale modeling and integration of physiological models carry challenges due to the complex nature of physiological processes. High coupling within and among scales present a significant challenge in constructing and integrating multiscale physiological models. In order to deal with such challenges in a systematic way, there is a significant need for an information technology framework together with related analytical and computational tools that will facilitate integration of models and simulations of complex biological systems. Physiological Model Simulation, Integration and Modeling Framework (Phy-SIM) is an information technology framework providing the tools to facilitate development, integration and simulation of integrated models of human physiology. Phy-SIM brings software level solutions to the challenges raised by the complex nature of physiological systems. The aim of Phy-SIM, and this paper is to lay some foundation with the new approaches such as information flow and modular representation of the physiological models. The ultimate goal is to enhance the development of both the models and the integration approaches of multiscale physiological processes and thus this paper focuses on the design approaches that would achieve such a goal. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

A New Biogeochemical Computational Framework Integrated within the Community Land Model

NASA Astrophysics Data System (ADS)

Fang, Y.; Li, H.; Liu, C.; Huang, M.; Leung, L.

2012-12-01

Terrestrial biogeochemical processes, particularly carbon cycle dynamics, have been shown to significantly influence regional and global climate changes. Modeling terrestrial biogeochemical processes within the land component of Earth System Models such as the Community Land model (CLM), however, faces three major challenges: 1) extensive efforts in modifying modeling structures and rewriting computer programs to incorporate biogeochemical processes with increasing complexity, 2) expensive computational cost to solve the governing equations due to numerical stiffness inherited from large variations in the rates of biogeochemical processes, and 3) lack of an efficient framework to systematically evaluate various mathematical representations of biogeochemical processes. To address these challenges, we introduce a new computational framework to incorporate biogeochemical processes into CLM, which consists of a new biogeochemical module with a generic algorithm and reaction database. New and updated biogeochemical processes can be incorporated into CLM without significant code modification. To address the stiffness issue, algorithms and criteria will be developed to identify fast processes, which will be replaced with algebraic equations and decoupled from slow processes. This framework can serve as a generic and user-friendly platform to test out different mechanistic process representations and datasets and gain new insight on the behavior of the terrestrial ecosystems in response to climate change in a systematic way.

Signal processing for non-destructive testing of railway tracks

NASA Astrophysics Data System (ADS)

Heckel, Thomas; Casperson, Ralf; Rühe, Sven; Mook, Gerhard

2018-04-01

Increased speed, heavier loads, altered material and modern drive systems result in an increasing number of rail flaws. The appearance of these flaws also changes continually due to the rapid change in damage mechanisms of modern rolling stock. Hence, interpretation has become difficult when evaluating non-destructive rail testing results. Due to the changed interplay between detection methods and flaws, the recorded signals may result in unclassified types of rail flaws. Methods for automatic rail inspection (according to defect detection and classification) undergo continual development. Signal processing is a key technology to master the challenge of classification and maintain resolution and detection quality, independent of operation speed. The basic ideas of signal processing, based on the Glassy-Rail-Diagram for classification purposes, are presented herein. Examples for the detection of damages caused by rolling contact fatigue also are given, and synergetic effects of combined evaluation of diverse inspection methods are shown.

Using Speech Recognition Software to Improve Writing Skills

ERIC Educational Resources Information Center

Diaz, Felix

2014-01-01

Orthopedically impaired (OI) students face a formidable challenge during the writing process due to their limited or non-existing ability to use their hands to hold a pen or pencil or even to press the keys on a keyboard. While they may have a clear mental picture of what they want to write, the biggest hurdle comes well before having to tackle…

Fluid Bed Dehydration of Magnesium Chloride

NASA Astrophysics Data System (ADS)

Adham, K.; Lee, C.; O'Keefe, K.

Molten salt electrolysis of MgCl2 is commonly used for the production of magnesium metal. However, the electrolysis feed must be completely dry with minimum oxygen content. Therefore, complete dehydration of the MgCl2 brine or the hydrated prill is a required process, which is very challenging because of the ease of thermal degradation due to hydrolysis of magnesium chloride.

Asylum, Participation and the Best Interests of the Child: New Lessons from Norway

ERIC Educational Resources Information Center

Liden, Hilde; Rusten, Hilde

2007-01-01

This article discusses Norway's implementation of the Convention on the Rights of the Child (CRC) in relation to the field of asylum. In particular, we explore the dilemmas and challenges posed by efforts to realise children's right to express their views and have these views given due weight in decision-making processes as stipulated in Article…

Calibration and validation of the SWAT model for a forested watershed in coastal South Carolina

Treesearch

Devendra M. Amatya; Elizabeth B. Haley; Norman S. Levine; Timothy J. Callahan; Artur Radecki-Pawlik; Manoj K. Jha

2008-01-01

Modeling the hydrology of low-gradient coastal watersheds on shallow, poorly drained soils is a challenging task due to the complexities in watershed delineation, runoff generation processes and pathways, flooding, and submergence caused by tropical storms. The objective of the study is to calibrate and validate a GIS-based spatially-distributed hydrologic model, SWAT...

New plastic recycling technology | Science Inventory | US EPA

EPA Pesticide Factsheets

Greater than 60% of the total plastic content of municipal solid waste is comprised of polyolefins (high-density, low-density, and linear polyethylene and polypropylene. Polyethylene (PE) is the largest-volume component but presents a challenge due to the absence of low-energy degradation processes. This news column provides a digest of recent technical reports relating to clean technology and environmental policy,

Affordances of the Cultural Inquiry Process in Building Secondary Mathematics Teachers' Capacity for Cultural Responsiveness

ERIC Educational Resources Information Center

Parker, Frieda; Bartell, Tonya; Novak, Jodie D.

2017-01-01

Over the last couple of decades, there has been a growing call for teachers to become more responsive to the increasing cultural diversity of students as a means of improving students' experiences in school and their learning outcomes. Challenges exist in working with secondary mathematics teachers due to the common belief that math is…

Engaging Biology Undergraduates in the Scientific Process through Writing a Theoretical Research Proposal

ERIC Educational Resources Information Center

Stanford, Jennifer S.; Duwel, Laura E.

2013-01-01

It has been suggested that research experiences are an important element that should be included in all undergraduate Biology curricula. This is a difficult suggestion to accommodate due to issues with cost, space and time. We addressed this challenge through development of a capstone project in which Biology majors work in groups to develop novel…

Artful Language: Academic Writing for the Art Student

ERIC Educational Resources Information Center

Apps, Linda; Mamchur, Carolyn

2009-01-01

The task of writing about the process of making and contextualising art can be overwhelming for some graduate students. While the challenge may be due in part to limited time and attention to the practice of writing, in a practice-based arts thesis there is a deeper issue: how the visual and written components are attended to in a manner that…

Secure Skyline Queries on Cloud Platform.

PubMed

Liu, Jinfei; Yang, Juncheng; Xiong, Li; Pei, Jian

2017-04-01

Outsourcing data and computation to cloud server provides a cost-effective way to support large scale data storage and query processing. However, due to security and privacy concerns, sensitive data (e.g., medical records) need to be protected from the cloud server and other unauthorized users. One approach is to outsource encrypted data to the cloud server and have the cloud server perform query processing on the encrypted data only. It remains a challenging task to support various queries over encrypted data in a secure and efficient way such that the cloud server does not gain any knowledge about the data, query, and query result. In this paper, we study the problem of secure skyline queries over encrypted data. The skyline query is particularly important for multi-criteria decision making but also presents significant challenges due to its complex computations. We propose a fully secure skyline query protocol on data encrypted using semantically-secure encryption. As a key subroutine, we present a new secure dominance protocol, which can be also used as a building block for other queries. Finally, we provide both serial and parallelized implementations and empirically study the protocols in terms of efficiency and scalability under different parameter settings, verifying the feasibility of our proposed solutions.

The Challenges in the Development of a Long Duration Space Mission Food System

NASA Technical Reports Server (NTRS)

Perchonok, Michele H.; Swango, Beverly; Toerne, Mary E.; Russo, Dane M. (Technical Monitor)

2001-01-01

The Advanced Food System at Johnson Space Center/NASA will be responsible for supplying food to the crew for long duration exploratory missions. These missions require development of both a Transit Food System and of a Planetary Food System. The Transit Food System will consist of pre-packaged food of extended shelf life. It will be supplemented with salad crops that will be consumed fresh. The challenge is to develop a food system with a shelf life of 3 - 5 years that will use minimal power and create minimal waste from the food packaging. The Planetary Food System will allow for food processing of crops grown on the planetary surface due to the presence of some gravitational force. Crops will be processed to final products to provide a nutritious and acceptable diet for the crew. The food system must be flexible due to crop variation, availability, and shelf life. Crew meals, based on thesc: crops, must be nutritious, high quality, safe, and contain variety. The Advanced Food System becomes a fulcrum creating the right connection from crops to crew meals while dealing with issues of integration within a closed self-regenerative system (e.g., safety, waste production, volumes, water usage, etc.).

Mode-converting coupler for silicon-on-sapphire devices

NASA Astrophysics Data System (ADS)

Zlatanovic, S.; Offord, B. W.; Owen, M.; Shimabukuro, R.; Jacobs, E. W.

2015-02-01

Silicon-on-sapphire devices are attractive for the mid-infrared optical applications up to 5 microns due to the low loss of both silicon and sapphire in this wavelength band. Designing efficient couplers for silicon-on-sapphire devices presents a challenge due to a highly confined mode in silicon and large values of refractive index of both silicon and sapphire. Here, we present design, fabrication, and measurements of a mode-converting coupler for silicon-on-sapphire waveguides. We utilize a mode converter layout that consists of a large waveguide that is overlays a silicon inverse tapered waveguide. While this geometry was previously utilized for silicon-on-oxide devices, the novelty is in using materials that are compatible with the silicon-on-sapphire platform. In the current coupler the overlaying waveguide is made of silicon nitride. Silicon nitride is the material of choice because of the large index of refraction and low absorption from near-infrared to mid-infrared. The couplers were fabricated using a 0.25 micron silicon-on-sapphire process. The measured coupling loss from tapered lensed silica fibers to the silicon was 4.8dB/coupler. We will describe some challenges in fabrication process and discuss ways to overcome them.

Challenges and solutions to incorporation of nutraceuticals in foods.

PubMed

Augustin, Mary Ann; Sanguansri, Luz

2015-01-01

Manufacturers often cannot simply add a nutraceutical to a food when formulating functional foods that have acceptable sensory appeal as well as the desired health benefits. The appropriate application of microencapsulation for stabilizing nutraceuticals enables their effective delivery through food. Careful design of the delivery system helps protect sensitive nutraceuticals from the environment and processing stresses encountered during food manufacture, and prevents undesirable interactions of the nutraceutical with components in the food matrix. Microencapsulation technologies overcome hurdles associated with the successful delivery of nutraceuticals in healthy foods if due consideration is given to challenges at all stages throughout the supply chain. This encompasses stabilizing and protecting nutraceuticals from degradation in ingredient formats, during processing, in the final food product, and during intestinal transit until they are released at the desired site in the gastrointestinal tract to impart their targeted health effects.

Privacy preserving processing of genomic data: A survey.

PubMed

Akgün, Mete; Bayrak, A Osman; Ozer, Bugra; Sağıroğlu, M Şamil

2015-08-01

Recently, the rapid advance in genome sequencing technology has led to production of huge amount of sensitive genomic data. However, a serious privacy challenge is confronted with increasing number of genetic tests as genomic data is the ultimate source of identity for humans. Lately, privacy threats and possible solutions regarding the undesired access to genomic data are discussed, however it is challenging to apply proposed solutions to real life problems due to the complex nature of security definitions. In this review, we have categorized pre-existing problems and corresponding solutions in more understandable and convenient way. Additionally, we have also included open privacy problems coming with each genomic data processing procedure. We believe our classification of genome associated privacy problems will pave the way for linking of real-life problems with previously proposed methods. Copyright © 2015 Elsevier Inc. All rights reserved.

Processing of Onion-like Carbon for Electrochemical Capacitors

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

Van Aken, Katherine L.; Maleski, Kathleen; Mathis, Tyler S.

Multi-shell fullerenes known as onion-like carbon (OLC) are especially attractive in applications relative to energy storage, such as electrochemical capacitors, due to a near-spherical shape of particles, their nanoscale diameters and high conductivity leading to fast rate performance. Because of this, onion-like carbon can be fabricated into electrodes, used as a conductive additive, and may have potential in composites and additive manufacturing. However due to agglomeration of OLC particles, creating a stable, aqueous dispersion for ink production or formulating composites proves challenging. Also, we explore how attrition milling, acid treatment, and probe sonication can be employed to decrease agglomeration andmore » provide colloidal stability in aqueous media. We also investigate how the electrochemical performance changes with each processing step as well as the treatments in succession. When tested in electrochemical capacitors, the processing increases the capacitance by a factor of three, due to an added pseudocapacitive contribution which is not present in untreated OLC. As a result, the processing of OLC proves to be advantageous for the production of stable, aqueous solutions, which also exhibit improved electrochemical properties suitable for functional inks, conductive additives, and fabrication of composite electrodes.« less

Processing of Onion-like Carbon for Electrochemical Capacitors

DOE PAGES

Van Aken, Katherine L.; Maleski, Kathleen; Mathis, Tyler S.; ...

2017-02-04

Multi-shell fullerenes known as onion-like carbon (OLC) are especially attractive in applications relative to energy storage, such as electrochemical capacitors, due to a near-spherical shape of particles, their nanoscale diameters and high conductivity leading to fast rate performance. Because of this, onion-like carbon can be fabricated into electrodes, used as a conductive additive, and may have potential in composites and additive manufacturing. However due to agglomeration of OLC particles, creating a stable, aqueous dispersion for ink production or formulating composites proves challenging. Also, we explore how attrition milling, acid treatment, and probe sonication can be employed to decrease agglomeration andmore » provide colloidal stability in aqueous media. We also investigate how the electrochemical performance changes with each processing step as well as the treatments in succession. When tested in electrochemical capacitors, the processing increases the capacitance by a factor of three, due to an added pseudocapacitive contribution which is not present in untreated OLC. As a result, the processing of OLC proves to be advantageous for the production of stable, aqueous solutions, which also exhibit improved electrochemical properties suitable for functional inks, conductive additives, and fabrication of composite electrodes.« less

Digitalizing historical high resolution water level data: Challenges and opportunities

NASA Astrophysics Data System (ADS)

Holinde, Lars; Hein, Hartmut; Barjenbruch, Ulrich

2017-04-01

Historical tide-gauge data offer the opportunities for determining variations in key characteristics for water level data and the analyses of past extreme events (storm surges). These information are important for calculating future trends and scenarios. But there are challenges involved due to the extensive effort needed to digitalize gauge sheets and quality control the resulting historical data. Based on these conditions, two main sources for inaccuracies in historical time series can be identified. First are several challenges due to the digitalization of the historical data, e.g. general quality of the sheets, multiple crossing lines of the observed water levels and additional comments on the sheet describing problems or additional information during the measurements. Second are problems during the measurements themselves. These can include the incorrect positioning of the sheets, trouble with the tide-gauge and maintenance. Errors resulting from these problems can be e.g. flat lines, discontinuities and outlier. Especially, the characterization of outliers has to be conducted carefully, to distinguish between real outliers and the appearance of extreme events. Methods for the quality control process involve the use of statistics, machine learning and neural networks. These will be described and applied to three different time series from tide gauge stations at the cost of Lower Saxony, Germany. Resulting difficulties and outcomes of the quality control process will be presented and explained. Furthermore, we will present a first glance at analyses for these time series.

Challenging an immediate suspension of a DEA registration: is it time for a new tact?

PubMed

Behr, Douglas J

2014-01-01

A Drug Enforcement Administration ("DEA") registration is not only a necessity, but also an invaluable commodity for doctors, pharmacists, hospitals and drug wholesalers who prescribe, stock, and distribute controlled substances. While the DEA may only suspend a registration by issuing an immediate suspension order ("ISO) after an ex parte finding of "imminent danger to the public health or safety," the law fails to explicitly protect the registrant by way of a post-suspension hearing on the ISO, despite the registrant's constitutionally protected property interest in the registration. A registrant has only two procedural options--which are often unsuccessful--to challenge the ISO: endure a long and arduous administrative review proceeding or petition the court for a "not-so-easily proven" injunction, all the while the suspension remains in effect and the controlled substance business operations cease. Accordingly, a suspension of the registration may be certain death to doctors and pharmacists without the financial means to operate the business in the absence of the registration. Because the DEA registration is a constitutionally-protected interest, there is a better way to challenge the suspension. The Supreme Court has held that once a license is issued, the continued possession of it is essential to the registrant's livelihood. Therefore suspension or revocation of such a protected interest requires due process. Due-process hearings, while varied, will provide the necessary avenues of review to provide a fair review of the justification of the suspension and its continuance, i.e., whether there truly is imminent danger to public health or safety and whether the suspension is overbroad and should be limited. To date, this thesis remains to be tested and awaits a petitioner with a justiciable claim and the financial resources to challenge the DEA in court. But in the field of DEA ISO challenges, it is time for a new tact!

EvoGraph: On-The-Fly Efficient Mining of Evolving Graphs on GPU

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

Sengupta, Dipanjan; Song, Shuaiwen

With the prevalence of the World Wide Web and social networks, there has been a growing interest in high performance analytics for constantly-evolving dynamic graphs. Modern GPUs provide massive AQ1 amount of parallelism for efficient graph processing, but the challenges remain due to their lack of support for the near real-time streaming nature of dynamic graphs. Specifically, due to the current high volume and velocity of graph data combined with the complexity of user queries, traditional processing methods by first storing the updates and then repeatedly running static graph analytics on a sequence of versions or snapshots are deemed undesirablemore » and computational infeasible on GPU. We present EvoGraph, a highly efficient and scalable GPU- based dynamic graph analytics framework.« less

Exploring the Notion of Context in Medical Data.

PubMed

Mylonas, Phivos

2017-01-01

Scientific and technological knowledge and skills are becoming crucial for most data analysis activities. Two rather distinct, but at the same time collaborating, domains are the ones of computer science and medicine; the former offers significant aid towards a more efficient understanding of the latter's research trends. Still, the process of meaningfully analyzing and understanding medical information and data is a tedious one, bound to several challenges. One of them is the efficient utilization of contextual information in the process leading to optimized, context-aware data analysis results. Nowadays, researchers are provided with tools and opportunities to analytically study medical data, but at the same time significant and rather complex computational challenges are yet to be tackled, among others due to the humanistic nature and increased rate of new content and information production imposed by related hardware and applications. So, the ultimate goal of this position paper is to provide interested parties an overview of major contextual information types to be identified within the medical data processing framework.

A Software Product Line Process to Develop Agents for the IoT.

PubMed

Ayala, Inmaculada; Amor, Mercedes; Fuentes, Lidia; Troya, José M

2015-07-01

One of the most important challenges of this decade is the Internet of Things (IoT), which aims to enable things to be connected anytime, anyplace, with anything and anyone, ideally using any path/network and any service. IoT systems are usually composed of heterogeneous and interconnected lightweight devices that support applications that are subject to change in their external environment and in the functioning of these devices. The management of the variability of these changes, autonomously, is a challenge in the development of these systems. Agents are a good option for developing self-managed IoT systems due to their distributed nature, context-awareness and self-adaptation. Our goal is to enhance the development of IoT applications using agents and software product lines (SPL). Specifically, we propose to use Self-StarMASMAS, multi-agent system) agents and to define an SPL process using the Common Variability Language. In this contribution, we propose an SPL process for Self-StarMAS, paying particular attention to agents embedded in sensor motes.

Improving the estimation of flavonoid intake for study of health outcomes

PubMed Central

Dwyer, Johanna T.; Jacques, Paul F.; McCullough, Marjorie L.

2015-01-01

Imprecision in estimating intakes of non-nutrient bioactive compounds such as flavonoids is a challenge in epidemiologic studies of health outcomes. The sources of this imprecision, using flavonoids as an example, include the variability of bioactive compounds in foods due to differences in growing conditions and processing, the challenges in laboratory quantification of flavonoids in foods, the incompleteness of flavonoid food composition tables, and the lack of adequate dietary assessment instruments. Steps to improve databases of bioactive compounds and to increase the accuracy and precision of the estimation of bioactive compound intakes in studies of health benefits and outcomes are suggested. PMID:26084477

A review on management of chrome-tanned leather shavings: a holistic paradigm to combat the environmental issues.

PubMed

Pati, Anupama; Chaudhary, Rubina; Subramani, Saravanabhavan

2014-10-01

Raw hide/skins come to the tanners as a by-product of meat industry which is converted into value-added leather as product for fashion market. Leather manufacturing is a chemical process of natural biological matrix. It employs a huge quantity of water and inorganic and organic chemicals for processing and thereby discharges solid and liquid wastes into the environment. One of the potential solid wastes generated from leather industry is chrome-tanned leather shavings (CTLSs), and its disposal is increasingly becoming a huge challenge on disposal to tanners due to presence of heavy metal chromium. Hence, finding a sustainable solution to the CTLS disposal problem is a prime challenge for global tanners and researchers. This paper aims to the deeper review of various disposal methods on CTLS such as protein, chromium, and energy recovery processes and its utilization methodologies. Sustainable technologies have been developed to overcome CTLS solid wastes emanating from leather processing operations. Further, this review paper brings a broader classification of developed methodologies for treatment of CTLSs.

Pen-based computers: Computers without keys

NASA Technical Reports Server (NTRS)

Conklin, Cheryl L.

1994-01-01

The National Space Transportation System (NSTS) is comprised of many diverse and highly complex systems incorporating the latest technologies. Data collection associated with ground processing of the various Space Shuttle system elements is extremely challenging due to the many separate processing locations where data is generated. This presents a significant problem when the timely collection, transfer, collation, and storage of data is required. This paper describes how new technology, referred to as Pen-Based computers, is being used to transform the data collection process at Kennedy Space Center (KSC). Pen-Based computers have streamlined procedures, increased data accuracy, and now provide more complete information than previous methods. The end results is the elimination of Shuttle processing delays associated with data deficiencies.

Toxicological challenges to microbial bioethanol production and strategies for improved tolerance

DOE PAGES

Akinsho, Hannah; Rydzak, Thomas; Borole, Abhijeet P.; ...

2015-09-30

Bioethanol production output has increased steadily over the last two decades and is now beginning to become competitive with traditional liquid transportation fuels due to advances in engineering, the identification of new production host organisms, and the development of novel biodesign strategies. A significant portion of these efforts has been dedicated to mitigating the toxicological challenges encountered across the bioethanol production process. From the release of potentially cytotoxic or inhibitory compounds from input feedstocks, through the metabolic co-synthesis of ethanol and potentially detrimental byproducts, and to the potential cytotoxicity of ethanol itself, each stage of bioethanol production requires the applicationmore » of genetic or engineering controls that ensure the host organisms remain healthy and productive to meet the necessary economies required for large scale production. In addition, as production levels continue to increase, there is an escalating focus on the detoxification of the resulting waste streams to minimize their environmental impact. Thus, this review will present the major toxicological challenges encountered throughout each stage of the bioethanol production process and the commonly employed strategies for reducing or eliminating potential toxic effects.« less

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.

Wafer-shape metrics based foundry lithography

NASA Astrophysics Data System (ADS)

Kim, Sungtae; Liang, Frida; Mileham, Jeffrey; Tsai, Damon; Bouche, Eric; Lee, Sean; Huang, Albert; Hua, C. F.; Wei, Ming Sheng

2017-03-01

As device shrink, there are many difficulties with process integration and device yield. Lithography process control is expected to be a major challenge due to tighter overlay and focus control requirement. The understanding and control of stresses accumulated during device fabrication has becoming more critical at advanced technology nodes. Within-wafer stress variations cause local wafer distortions which in turn present challenges for managing overlay and depth of focus during lithography. A novel technique for measuring distortion is Coherent Gradient Sensing (CGS) interferometry, which is capable of generating a high-density distortion data set of the full wafer within a time frame suitable for a high volume manufacturing (HVM) environment. In this paper, we describe the adoption of CGS (Coherent Gradient Sensing) interferometry into high volume foundry manufacturing to overcome these challenges. Leveraging this high density 3D metrology, we characterized its In-plane distortion as well as its topography capabilities applied to the full flow of an advanced foundry manufacturing. Case studies are presented that summarize the use of CGS data to reveal correlations between in-plane distortion and overlay variation as well as between topography and device yield.

Negotiating and Reshaping Christian Values and Professional Identities through Action Research: Experiential Learning and Professional Development among Christian Religious Education Teachers

ERIC Educational Resources Information Center

Johannessen, Øystein Lund

2015-01-01

In European societies, major patterns of plurality have changed over recent decades due to modernization and globalization. In schools, these new patterns of plurality have consequences for learning processes and may be challenging for students and teachers. This article investigates these issues, taking as its point of departure the way they…

The Transmission of Environmental Values from Sources of Influence to Young Adults: Toward an Understanding of the Process Leading to Environmental Values Internalization

ERIC Educational Resources Information Center

Depper, Gina L.

2017-01-01

The world faces significant environmental challenges due largely to unsustainable human behavior. Values have been found to be a direct and indirect predictor of human behavior and understanding how they are formed/influenced is critical to any strategy of behavioral change. Our understanding of how environmental values are transmitted and…

Direct Numerical Simulations of Concentration and Temperature Polarization in Direct Contact Membrane Distillation

NASA Astrophysics Data System (ADS)

Lou, Jincheng; Tilton, Nils

2017-11-01

Membrane distillation (MD) is a method of desalination with boundary layers that are challenging to simulate. MD is a thermal process in which warm feed and cool distilled water flow on opposite sides of a hydrophobic membrane. The temperature difference causes water to evaporate from the feed, travel through the membrane, and condense in the distillate. Two challenges to MD are temperature and concentration polarization. Temperature polarization represents a reduction in the transmembrane temperature difference due to heat transfer through the membrane. Concentration polarization describes the accumulation of solutes near the membrane. These phenomena reduce filtration and lead to membrane fouling. They are difficult to simulate due to the coupling between the velocity, temperature, and concentration fields on the membrane. Unsteady regimes are particularly challenging because noise at the outlets can pollute the near-membrane flow fields. We present the development of a finite-volume method for the simulation of fluid flow, heat, and mass transport in MD systems. Using the method, we perform a parametric study of the polarization boundary layers, and show that the concentration boundary layer shows self-similar behavior that satisfies power laws for the downstream growth. Funded by the U.S. Bureau of Reclamation.

Occupational Rhinoconjunctivitis due to Maize in a Snack Processor: A Cross-Reactivity Study Between Lipid Transfer Proteins From Different Cereals and Peach.

PubMed

Guillen, Daiana; Barranco, Pilar; Palacín, Arantxa; Quirce, Santiago

2014-09-01

We report the case of a snack processor who developed occupational rhinoconjunctivitis due to maize brand exposure during the extrusion process, and who experienced abdominal pain upon drinking beer. The allergens implicated and the cross-reactivity between non-specific lipid transfer proteins (LTPs) from different cereals and peach were investigated. Skin prick tests and specific IgE to cereal flours, pulmonary functions tests and specific conjunctival and inhalation challenges to maize extract were performed. In vitro studies included IgE immunoblotting and ELISA inhibition assays. Skin prick tests with maize flour, maize brand and wheat flour extracts were positive, whereas serum specific IgE was positive only to maize flour. Specific inhalation challenge (SIC) to maize flour did not elicit an asthmatic reaction; however, conjunctival challenge test with the same extract was positive. Patient's serum recognized IgE-binding bands in the maize and beer extracts corresponding to LTPs. In the ELISA inhibition assays, a significant degree of allergenic cross-reactivity was found between maize and beer LTPs, whereas no cross-reactivity was observed between maize LTP and wheat and peach LTPs.

Effects of Cavity on the Performance of Dual Throat Nozzle During the Thrust-Vectoring Starting Transient Process.

PubMed

Gu, Rui; Xu, Jinglei

2014-01-01

The dual throat nozzle (DTN) technique is capable to achieve higher thrust-vectoring efficiencies than other fluidic techniques, without compromising thrust efficiency significantly during vectoring operation. The excellent performance of the DTN is mainly due to the concaved cavity. In this paper, two DTNs of different scales have been investigated by unsteady numerical simulations to compare the parameter variations and study the effects of cavity during the vector starting process. The results remind us that during the vector starting process, dynamic loads may be generated, which is a potentially challenging problem for the aircraft trim and control.

Study of Nickel Silicide as a Copper Diffusion Barrier in Monocrystalline Silicon Solar Cells

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

Kale, Abhijit; Beese, Emily; Saenz, Theresa

NiSi as a conductive diffusion barrier to silicon has been studied. We demonstrate that the NiSi films formed using the single step annealing process are as good as the two step process using XRD and Raman. Quality of NiSi films formed using e-beam Ni and electroless Ni process has been compared. Incomplete surface coverage and presence of constituents other than Ni are the main challenges with electroless Ni. We also demonstrate that Cu reduces the thermal stability of NiSi films. The detection of Cu has proven to be difficult due to temperature limitations.

Strategies to Suspension Serum-Free Adaptation of Mammalian Cell Lines for Recombinant Glycoprotein Production.

PubMed

Caron, Angelo Luis; Biaggio, Rafael Tagé; Swiech, Kamilla

2018-01-01

Serum-free suspension cultures are preferably required for recombinant protein production due to its readiness in upstream/downstream processing and scale-up, therefore increasing process productivity and competitiveness. This type of culture replaces traditional cell culturing as the presence of animal-derived components may introduce lot-a-lot variability and adventitious pathogens to the process. However, adapting cells to serum-free conditions is challenging, time-consuming, and cell line and medium dependent. In this chapter, we present different approaches that can be used to adapt mammalian cell lines from an anchorage-dependent serum supplemented culture to a suspension serum-free culture.

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

Anaerobic digestion of food waste - Challenges and opportunities.

PubMed

Xu, Fuqing; Li, Yangyang; Ge, Xumeng; Yang, Liangcheng; Li, Yebo

2018-01-01

The disposal of large amounts of food waste has caused significant environmental pollution and financial costs globally. Compared with traditional disposal methods (i.e., landfilling, incineration, and composting), anaerobic digestion (AD) is a promising technology for food waste management, but has not yet been fully applied due to a few technical and social challenges. This paper summarizes the quantity, composition, and methane potential of various types of food waste. Recent research on different strategies to enhance AD of food waste, including co-digestion, addition of micronutrients, control of foaming, and process design, is discussed. It is envisaged that AD of food waste could be combined with an existing AD facility or be integrated with the production of value-added products to reduce costs and increase revenue. Further understanding of the fundamental biological and physicochemical processes in AD is required to improve the technology. Copyright © 2017 Elsevier Ltd. All rights reserved.

Factors governing dissolution process of lignocellulosic biomass in ionic liquid: current status, overview and challenges.

PubMed

Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

2015-02-01

The utilisation of non-feed lignocellulosic biomass as a source of renewable bio-energy and synthesis of fine chemical products is necessary for the sustainable development. The methods for the dissolution of lignocellulosic biomass in conventional solvents are complex and tedious due to the complex chemical ultra-structure of biomass. In view of this, recent developments for the use of ionic liquid solvent (IL) has received great attention, as ILs can solubilise such complex biomass and thus provides industrial scale-up potential. In this review, we have discussed the state-of-art for the dissolution of lignocellulosic material in representative ILs. Furthermore, various process parameters and their influence for biomass dissolution were reviewed. In addition to this, overview of challenges and opportunities related to this interesting area is presented. Copyright © 2014 Elsevier Ltd. All rights reserved.

Improving Secondary Organic Aerosol (SOA) Models using Global Sensitivity Analysis and by Comparison to Chamber Data.

NASA Astrophysics Data System (ADS)

Miller, D. O.; Brune, W. H.

2017-12-01

Accurate estimates of secondary organic aerosol (SOA) from atmospheric models is a major research challenge due to the complexity of the chemical and physical processes involved in the SOA formation and continuous aging. The primary uncertainties of SOA models include those associated with the formation of gas-phase products, the conversion between gas phase and particle phase, the aging mechanisms of SOA, and other processes related to the heterogeneous and particle-phase reactions. To address this challenge, we us a modular modeling framework that combines both simple and near-explicit gas-phase reactions and a two-dimensional volatility basis set (2D-VBS) to simulate the formation and evolution of SOA. Global sensitivity analysis is used to assess the relative importance of the model input parameters. In addition, the model is compared to the measurements from the Focused Isoprene eXperiment at the California Institute of Technology (FIXCIT).

The difficulties of conducting maternal death reviews in Malawi.

PubMed

Kongnyuy, Eugene J; van den Broek, Nynke

2008-09-11

Maternal death reviews is a tool widely recommended to improve the quality of obstetric care and reduce maternal mortality. Our aim was to explore the challenges encountered in the process of facility-based maternal death review in Malawi, and to suggest sustainable and logically sound solutions to these challenges. SWOT (strengths, weaknesses, opportunities and threats) analysis of the process of maternal death review during a workshop in Malawi. Strengths: Availability of data from case notes, support from hospital management, and having maternal death review forms. Weaknesses: fear of blame, lack of knowledge and skills to properly conduct death reviews, inadequate resources and missing documentation. Opportunities: technical assistance from expatriates, support from the Ministry of Health, national protocols and high maternal mortality which serves as motivation factor. Threats: Cultural practices, potential lawsuit, demotivation due to the high maternal mortality and poor planning at the district level. Solutions: proper documentation, conducting maternal death review in a blame-free manner, good leadership, motivation of staff, using guidelines, proper stock inventory and community involvement. Challenges encountered during facility-based maternal death review are provider-related, administrative, client related and community related. Countries with similar socioeconomic profiles to Malawi will have similar 'pull-and-push' factors on the process of facility-based maternal death reviews, and therefore we will expect these countries to have similar potential solutions.

Unexpected ethical dilemmas in sex assignment in 46,XY DSD due to 5-alpha reductase type 2 deficiency.

PubMed

Byers, Heather M; Mohnach, Lauren H; Fechner, Patricia Y; Chen, Ming; Thomas, Inas H; Ramsdell, Linda A; Shnorhavorian, Margarett; McCauley, Elizabeth A; Amies Oelschlager, Anne-Marie E; Park, John M; Sandberg, David E; Adam, Margaret P; Keegan, Catherine E

2017-06-01

Sex assignment at birth remains one of the most clinically challenging and controversial topics in 46,XY disorders of sexual development (DSD). This is particularly challenging in deficiency of 5-alpha reductase type 2 given that external genitalia are typically undervirilized at birth but typically virilize at puberty to a variable degree. Historically, most individuals with 5-alpha reductase deficiency were raised females. However, reports that over half of patients who underwent a virilizing puberty adopted an adult male gender identity have challenged this practice. Consensus guidelines on assignment of sex of rearing at birth are equivocal or favor male assignment in the most virilized cases. While a male sex of rearing assignment may avoid lifelong hormonal therapy and/or allow the potential for fertility, female sex assignment may be more consistent with external anatomy in the most severely undervirilized cases. Herein, we describe five patients with 46,XY DSD due 5-alpha-reductase type 2 deficiency, all with a severe phenotype. An inter-disciplinary DSD medical team at one of two academic centers evaluated each patient. This case series illustrates the complicated decision-making process of assignment of sex of rearing at birth in 5-alpha reductase type 2 deficiency and the challenges that arise when the interests of the child, parental wishes, recommendations of the medical team, and state law collide. © 2017 Wiley Periodicals, Inc.

Therapists' Metacognitive Monitoring of the Psychotherapeutic Process With Patients With Borderline Personality Disorder.

PubMed

Bourke, Marianne E; Grenyer, Brin F S

2017-07-01

Therapy for borderline personality disorder (BPD) is challenging, in part, because of the impact of BPD on the therapeutic relationship. The therapist's metacognitive capacity within therapy may be perturbed due to the complexity of verbal and nonverbal affect and cognition in the therapeutic interchange; however, research on this issue is lacking. Therapists (N=20 clinical psychologists) were asked to discuss the treatment process when working with their patients with BPD (N=40) and their patients with major depressive disorder (N=40). Verbatim transcripts of the therapists' verbalizations were then scored using computerized linguistic content analysis. When discussing their patients with BPD, clinicians used significantly fewer words associated with cognitive processes (think, understand, realize) or words indicating causation (cause, because, effect), and more first-person singular pronouns, and adverbs. When describing their depressed patients, the therapists used more words associated with negative emotions, anxiety, anger, and sadness than positive words. The results did not seem to be influenced by the therapists' age, sex, or years of experience. Reflection on the psychotherapeutic process with patients with BPD induced in therapists a self-focused, emotionally intense linguistic style dominated by references to themselves and their experience of intense emotional states. These results suggest that, when describing their work with patients with BPD, therapists experience metacognitive challenges and mentalization processes that may parallel the challenges therapists face when thinking and working during the psychotherapy sessions themselves. The results underscore the important role of supervision in assisting therapists to organize their reflective processes when working with patients with BPD.

Autocorrelated process control: Geometric Brownian Motion approach versus Box-Jenkins approach

NASA Astrophysics Data System (ADS)

Salleh, R. M.; Zawawi, N. I.; Gan, Z. F.; Nor, M. E.

2018-04-01

Existing of autocorrelation will bring a significant effect on the performance and accuracy of process control if the problem does not handle carefully. When dealing with autocorrelated process, Box-Jenkins method will be preferred because of the popularity. However, the computation of Box-Jenkins method is too complicated and challenging which cause of time-consuming. Therefore, an alternative method which known as Geometric Brownian Motion (GBM) is introduced to monitor the autocorrelated process. One real case of furnace temperature data is conducted to compare the performance of Box-Jenkins and GBM methods in monitoring autocorrelation process. Both methods give the same results in terms of model accuracy and monitoring process control. Yet, GBM is superior compared to Box-Jenkins method due to its simplicity and practically with shorter computational time.

Challenges in Modelling and Control of Offshore De-oiling Hydrocyclone Systems

NASA Astrophysics Data System (ADS)

Durdevic, Petar; Pedersen, Simon; Yang, Zhenyu

2017-01-01

Offshore de-oiling installations are facing an increasing challenge with regards to removing oil residuals from produced water prior to discharge into the ocean. The de-oiling of produced water is initially achieved in the primary separation processes using gravity-based multi-phase separators, which can effectively handle large amounts of oil-well fluids but may struggle with the efficient separation of small dispersed oil particles. Thereby hydrocyclone systems are commonly employed in the downstream Produced Water Treatment (PWT) process for further reducing the oil concentration in the produced water before it can be discharged into the ocean. The popularity of hydrocyclone technology in the offshore oil and gas industry is mainly due to its rugged design and low maintenance requirements. However, to operate and control this type of system in an efficient way is far less simple, and alternatively this task imposes a number of key control challenges. Specifically, there is much research to be performed in the direction of dynamic modelling and control of de-oiling hydrocyclone systems. The current solutions rely heavily on empirical trial-and-error approaches. This paper gives a brief review of current hydrocyclone control solutions and the remaining challenges and includes some of our recent work in this topic and ends with a motivation for future work.

A Review on Potential Issues and Challenges in MR Imaging

PubMed Central

Kanakaraj, Jagannathan

2013-01-01

Magnetic resonance imaging is a noninvasive technique that has been developed for its excellent depiction of soft tissue contrasts. Instruments capable of ultra-high field strengths, ≥7 Tesla, were recently engineered and have resulted in higher signal-to-noise and higher resolution images. This paper presents various subsystems of the MR imaging systems like the magnet subsystem, gradient subsystem, and also various issues which arise due to the magnet. Further, it also portrays finer details about the RF coils and transceiver and also various limitations of the RF coils and transceiver. Moreover, the concept behind the data processing system and the challenges related to it were also depicted. Finally, the various artifacts associated with the MR imaging were clearly pointed out. It also presents a brief overview about all the challenges related to MR imaging systems. PMID:24381523

Engineering empty space between Si nanoparticles for lithium-ion battery anodes.

PubMed

Wu, Hui; Zheng, Guangyuan; Liu, Nian; Carney, Thomas J; Yang, Yuan; Cui, Yi

2012-02-08

Silicon is a promising high-capacity anode material for lithium-ion batteries yet attaining long cycle life remains a significant challenge due to pulverization of the silicon and unstable solid-electrolyte interphase (SEI) formation during the electrochemical cycles. Despite significant advances in nanostructured Si electrodes, challenges including short cycle life and scalability hinder its widespread implementation. To address these challenges, we engineered an empty space between Si nanoparticles by encapsulating them in hollow carbon tubes. The synthesis process used low-cost Si nanoparticles and electrospinning methods, both of which can be easily scaled. The empty space around the Si nanoparticles allowed the electrode to successfully overcome these problems Our anode demonstrated a high gravimetric capacity (~1000 mAh/g based on the total mass) and long cycle life (200 cycles with 90% capacity retention). © 2012 American Chemical Society

A Multi-Scale Integrated Approach to Representing Watershed Systems: Significance and Challenges

NASA Astrophysics Data System (ADS)

Kim, J.; Ivanov, V. Y.; Katopodes, N.

2013-12-01

A range of processes associated with supplying services and goods to human society originate at the watershed level. Predicting watershed response to forcing conditions has been of high interest to many practical societal problems, however, remains challenging due to two significant properties of the watershed systems, i.e., connectivity and non-linearity. Connectivity implies that disturbances arising at any larger scale will necessarily propagate and affect local-scale processes; their local effects consequently influence other processes, and often convey nonlinear relationships. Physically-based, process-scale modeling is needed to approach the understanding and proper assessment of non-linear effects between the watershed processes. We have developed an integrated model simulating hydrological processes, flow dynamics, erosion and sediment transport, tRIBS-OFM-HRM (Triangulated irregular network - based Real time Integrated Basin Simulator-Overland Flow Model-Hairsine and Rose Model). This coupled model offers the advantage of exploring the hydrological effects of watershed physical factors such as topography, vegetation, and soil, as well as their feedback mechanisms. Several examples investigating the effects of vegetation on flow movement, the role of soil's substrate on sediment dynamics, and the driving role of topography on morphological processes are illustrated. We show how this comprehensive modeling tool can help understand interconnections and nonlinearities of the physical system, e.g., how vegetation affects hydraulic resistance depending on slope, vegetation cover fraction, discharge, and bed roughness condition; how the soil's substrate condition impacts erosion processes with an non-unique characteristic at the scale of a zero-order catchment; and how topographic changes affect spatial variations of morphologic variables. Due to feedback and compensatory nature of mechanisms operating in different watershed compartments, our conclusion is that a key to representing watershed systems lies in an integrated, interdisciplinary approach, whereby a physically-based model is used for assessments/evaluations associated with future changes in landuse, climate, and ecosystems.

FPGA chip performance improvement with gate shrink through alternating PSM 90nm process

NASA Astrophysics Data System (ADS)

Yu, Chun-Chi; Shieh, Ming-Feng; Liu, Erick; Lin, Benjamin; Ho, Jonathan; Wu, Xin; Panaite, Petrisor; Chacko, Manoj; Zhang, Yunqiang; Lei, Wen-Kang

2005-11-01

In the post-physical verification space called 'Mask Synthesis' a key component of design-for-manufacturing (DFM), double-exposure based, dark-field, alternating PSM (Alt-PSM) is being increasingly applied at the 90nm node in addition with other mature resolution enhancement techniques (RETs) such as optical proximity correction (OPC) and sub-resolution assist features (SRAF). Several high-performance IC manufacturers already use alt-PSM technology in 65nm production. At 90nm having strong control over the lithography process is a critical component in meeting targeted yield goals. However, implementing alt-PSM in production has been challenging due to several factors such as phase conflict errors, mask manufacturing, and the increased production cost due to the need for two masks in the process. Implementation of Alt-PSM generally requires phase compliance rules and proper phase topology in the layout and this has been successful for the technology node with these rules implemented. However, this may not be true for a mature, production process technology, in this case 90 nm. Especially, in the foundry-fabless business model where the foundry provides a standard set of design rules to its customers for a given process technology, and where not all the foundry customers require Alt-PSM in their tapeout flow. With minimum design changes, design houses usually are motivated by higher product performance for the existing designs. What follows is an in-depth review of the motivation to apply alt-PSM on a production FPGA, the DFM challenges to each partner faced, its effect on the tapeout flow, and how design, manufacturing, and EDA teams worked together to resolve phase conflicts, tapeout the chip, and finally verify the silicon results in production.

Nurse Perspectives on the Practical, Emotional, and Professional Impacts of Living and Working in Post-earthquake Canterbury, New Zealand.

PubMed

Johal, Sarbjit S; Mounsey, Zoe; Brannelly, Petula; Johnston, David M

2016-02-01

This report explores nurses' perspectives following the Canterbury (New Zealand) 2010-2011 earthquake sequence and the subsequent recovery process. Problem Little is known about the experiences of health care professionals during a disaster recovery process, and this research generates insights about the challenges faced. Qualitative semi-structured interviews were undertaken with 11 nurses from the Christchurch (New Zealand) area to explore the challenges faced by the nurses during and following the earthquakes. The interviews took place three years after the start of the earthquake experience to enable exploration of longer term aspects of the recovery process. The interview transcripts were analyzed and coded using a grounded theory approach. The data analysis identified that the nurses had faced a number of challenges and these were characterized as practical, emotional, and professional. While some of the challenges were short-lived in the aftermath of the earthquakes, some were long-lasting due to the extended nature of the recovery process. Dealing with house damage, insurance negotiations, and working in damaged environments had a negative impact on the nurses. The nurses experienced a range of emotions, both negative and positive, after the disaster, though many had needed time to elapse before feeling able to reflect on their experiences. The findings suggest that secondary stressors have a negative impact on the psychosocial recovery process. The nurses recognized that they received support from others and were also required to focus on others. Keeping busy appeared to be the most common coping strategy. This lack of reflection on their experiences may have resulted in delayed emotional responses. Some of the nurses changed their work role, hours, and responsibilities suggesting that working in this environment was having a detrimental impact. The research indicates the challenges faced by nurses in the initial impact of the earthquakes and during the longer term recovery process. There is a need to consider the psychosocial impact of working and living in a post-disaster context and to develop support packages to ensure the health and well-being of nurses in this environment.

Solution-Processed Organic and Halide Perovskite Transistors on Hydrophobic Surfaces.

PubMed

Ward, Jeremy W; Smith, Hannah L; Zeidell, Andrew; Diemer, Peter J; Baker, Stephen R; Lee, Hyunsu; Payne, Marcia M; Anthony, John E; Guthold, Martin; Jurchescu, Oana D

2017-05-31

Solution-processable electronic devices are highly desirable due to their low cost and compatibility with flexible substrates. However, they are often challenging to fabricate due to the hydrophobic nature of the surfaces of the constituent layers. Here, we use a protein solution to modify the surface properties and to improve the wettability of the fluoropolymer dielectric Cytop. The engineered hydrophilic surface is successfully incorporated in bottom-gate solution-deposited organic field-effect transistors (OFETs) and hybrid organic-inorganic trihalide perovskite field-effect transistors (HTP-FETs) fabricated on flexible substrates. Our analysis of the density of trapping states at the semiconductor-dielectric interface suggests that the increase in the trap density as a result of the chemical treatment is minimal. As a result, the devices exhibit good charge carrier mobilities, near-zero threshold voltages, and low electrical hysteresis.

Concise Review: Mind the Gap: Challenges in Characterizing and Quantifying Cell- and Tissue-Based Therapies for Clinical Translation

PubMed Central

Rayment, Erin A; Williams, David J

2010-01-01

There are many challenges associated with characterizing and quantifying cells for use in cell- and tissue-based therapies. From a regulatory perspective, these advanced treatments must not only be safe and effective but also be made by high-quality manufacturing processes that allow for on-time delivery of viable products. Although sterility assays can be adapted from conventional bioprocessing, cell- and tissue-based therapies require more stringent safety assessments, especially in relation to use of animal products, immune reaction, and potential instability due to extended culture times. Furthermore, cell manufacturers who plan to use human embryonic stem cells in their therapies need to be particularly stringent in their final purification steps, due to the unrestricted growth potential of these cells. This review summarizes the current issues in characterization and quantification for cell- and tissue-based therapies, dividing these challenges into the regulatory themes of safety, potency, and manufacturing quality. It outlines current assays in use, as well as highlights the limits of many of these product release tests. Mode of action is discussed, with particular reference to in vitro surrogate assays that can be used to provide information to correlate with proposed in vivo patient efficacy. Importantly, this review highlights the requirement for basic research to improve current knowledge on the in vivo fate of these treatments; as well as an improved stakeholder negotiation process to identify the measurement requirements that will ensure the manufacture of the best possible cell- and tissue-based therapies within the shortest timeframe for the most patient benefit. PMID:20333747

Legal challenges in neurological practice.

PubMed

Jayalakshmi, Sita; Vooturi, Sudhindra

2016-10-01

Clinical neuroscience has made tremendous advances over the last century. Neurology as a discipline is still considered challenging and at times risky due to the natural history and progressive course of few of the neurological diseases. Encouragingly, the patient and their caregivers are now increasingly willing to be actively involved in making decisions. The patients' relationship with the doctor is a reflection of the society. A society that is orienting itself toward "rating" and "feedback" has made this doctor-patient relationship, a consumer-service provider relationship. This perhaps is due to commercialization of health that usually accompanies globalization. Moreover, a rapid influx of information from potential erroneous sources such as the Internet has also made patient and caregivers not being hesitant to taking legal course in the case of adverse events during treatment or simply because of dissatisfaction. The purpose of the legal process initiated by patients with neurological ailments is more often to compensate for the income lost, physical and psychological anguish that accompanies disease and its treatment, and to fund treatment or rehabilitation requirements. However, it is not clearly established if monetary benefits acquired lead to better opportunities for recovery of the patient. The consumer protection act and commercialization of medical services may well have an adverse effect on the doctor and patient relationship. Hence, there is a great need for all medical professionals to mutually complement and update each other. This review examines legal (litigation) processes with special interest on medicolegal system in patients with neurological ailments and the challenges faced by the neurologist during day-to-day clinical practice.

Relative Binding Free Energy Calculations in Drug Discovery: Recent Advances and Practical Considerations.

PubMed

Cournia, Zoe; Allen, Bryce; Sherman, Woody

2017-12-26

Accurate in silico prediction of protein-ligand binding affinities has been a primary objective of structure-based drug design for decades due to the putative value it would bring to the drug discovery process. However, computational methods have historically failed to deliver value in real-world drug discovery applications due to a variety of scientific, technical, and practical challenges. Recently, a family of approaches commonly referred to as relative binding free energy (RBFE) calculations, which rely on physics-based molecular simulations and statistical mechanics, have shown promise in reliably generating accurate predictions in the context of drug discovery projects. This advance arises from accumulating developments in the underlying scientific methods (decades of research on force fields and sampling algorithms) coupled with vast increases in computational resources (graphics processing units and cloud infrastructures). Mounting evidence from retrospective validation studies, blind challenge predictions, and prospective applications suggests that RBFE simulations can now predict the affinity differences for congeneric ligands with sufficient accuracy and throughput to deliver considerable value in hit-to-lead and lead optimization efforts. Here, we present an overview of current RBFE implementations, highlighting recent advances and remaining challenges, along with examples that emphasize practical considerations for obtaining reliable RBFE results. We focus specifically on relative binding free energies because the calculations are less computationally intensive than absolute binding free energy (ABFE) calculations and map directly onto the hit-to-lead and lead optimization processes, where the prediction of relative binding energies between a reference molecule and new ideas (virtual molecules) can be used to prioritize molecules for synthesis. We describe the critical aspects of running RBFE calculations, from both theoretical and applied perspectives, using a combination of retrospective literature examples and prospective studies from drug discovery projects. This work is intended to provide a contemporary overview of the scientific, technical, and practical issues associated with running relative binding free energy simulations, with a focus on real-world drug discovery applications. We offer guidelines for improving the accuracy of RBFE simulations, especially for challenging cases, and emphasize unresolved issues that could be improved by further research in the field.

Reproductive Disorders in Snakes.

PubMed

Di Girolamo, Nicola; Selleri, Paolo

2017-05-01

Reproduction of snakes is one of the challenging aspects of herpetology medicine. Due to the complexity of reproduction, several disorders may present before, during, or after this process. This article describes the physical examination, and radiographic, ultrasonographic, and endoscopic findings associated with reproductive disorders in snakes. Surgical techniques used to resolve reproductive disorders in snakes are described. Finally, common reproductive disorders in snakes are individually discussed. Copyright © 2017 Elsevier Inc. All rights reserved.

FlavonQ: An Automated Data Processing Tool for Profiling Flavone/flavonol Glycosides Using Ultra High-performance Liquid Chromatography Diode Array Detection and High-Resolution Accurate-Mass Mass Spectrometry (UHPLC HRAM-MS)

USDA-ARS?s Scientific Manuscript database

Flavonoids are well-known for their health benefits and can be found in nearly every plant. There are more than 5,000 known flavonoids existing in foods. Profiling flavonoids in natural products poses great challenges due to the diversity of flavonoids, the lack of commercially available standards, ...

Medical journal peer review: process and bias.

PubMed

Manchikanti, Laxmaiah; Kaye, Alan D; Boswell, Mark V; Hirsch, Joshua A

2015-01-01

Scientific peer review is pivotal in health care research in that it facilitates the evaluation of findings for competence, significance, and originality by qualified experts. While the origins of peer review can be traced to the societies of the eighteenth century, it became an institutionalized part of the scholarly process in the latter half of the twentieth century. This was a response to the growth of research and greater subject specialization. With the current increase in the number of specialty journals, the peer review process continues to evolve to meet the needs of patients, clinicians, and policy makers. The peer review process itself faces challenges. Unblinded peer review might suffer from positive or negative bias towards certain authors, specialties, and institutions. Peer review can also suffer when editors and/or reviewers might be unable to understand the contents of the submitted manuscript. This can result in an inability to detect major flaws, or revelations of major flaws after acceptance of publication by the editors. Other concerns include potentially long delays in publication and challenges uncovering plagiarism, duplication, corruption and scientific misconduct. Conversely, a multitude of these challenges have led to claims of scientific misconduct and an erosion of faith. These challenges have invited criticism of the peer review process itself. However, despite its imperfections, the peer review process enjoys widespread support in the scientific community. Peer review bias is one of the major focuses of today's scientific assessment of the literature. Various types of peer review bias include content-based bias, confirmation bias, bias due to conservatism, bias against interdisciplinary research, publication bias, and the bias of conflicts of interest. Consequently, peer review would benefit from various changes and improvements with appropriate training of reviewers to provide quality reviews to maintain the quality and integrity of research without bias. Thus, an appropriate, transparent peer review is not only ideal, but necessary for the future to facilitate scientific progress.

Establishing and sustaining a biorepository network in Israel: challenges and progress.

PubMed

Cohen, Yehudit; Almog, Ronit; Onn, Amir; Itzhaki-Alfia, Ayelet; Meir, Karen

2013-12-01

Over the past 5 years, using European and North American biobanks as models, the grass-roots establishment of independently operating biobanks has occurred virtually simultaneously in large Israeli teaching hospitals. The process of establishing a national biorepository network in Israel has progressed slowly, sustained mainly by a few proponents working together on a personal level. Slow progress has been due to limited funding and the lack of a legal framework specific to biobanking activities. Recently, due to increasing pressure from the scientific community, the government has earmarked funds for a national biorepository network, and the structure is now being established. In forming a network, Israel's biobanks face certain difficulties, particularly lack of support. Additional challenges include harmonization of standard operating procedures, database centralization, and use of a common informed consent form. In this article, we highlight some of the issues faced by Israel's biobank managers in establishing and sustaining a functional biobank network, information that could provide guidance for other small countries with limited resources.

Polymer structure-property requirements for stereolithographic 3D printing of soft tissue engineering scaffolds.

PubMed

Mondschein, Ryan J; Kanitkar, Akanksha; Williams, Christopher B; Verbridge, Scott S; Long, Timothy E

2017-09-01

This review highlights the synthesis, properties, and advanced applications of synthetic and natural polymers 3D printed using stereolithography for soft tissue engineering applications. Soft tissue scaffolds are of great interest due to the number of musculoskeletal, cardiovascular, and connective tissue injuries and replacements humans face each year. Accurately replacing or repairing these tissues is challenging due to the variation in size, shape, and strength of different types of soft tissue. With advancing processing techniques such as stereolithography, control of scaffold resolution down to the μm scale is achievable along with the ability to customize each fabricated scaffold to match the targeted replacement tissue. Matching the advanced manufacturing technique to polymer properties as well as maintaining the proper chemical, biological, and mechanical properties for tissue replacement is extremely challenging. This review discusses the design of polymers with tailored structure, architecture, and functionality for stereolithography, while maintaining chemical, biological, and mechanical properties to mimic a broad range of soft tissue types. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Challenge of Producing Fiber-Based Organic Electronic Devices

PubMed Central

Könyves-Toth, Tobias; Gassmann, Andrea; von Seggern, Heinz

2014-01-01

The implementation of organic electronic devices on fibers is a challenging task, not yet investigated in detail. As was shown earlier, a direct transition from a flat device structure to a fiber substrate is in principle possible. However, a more detailed investigation of the process reveals additional complexities than just the transition in geometry. It will be shown, that the layer formation of evaporated materials behaves differently due to the multi-angled incidence on the fibers surface. In order to achieve homogenous layers the evaporation process has to be adapted. Additionally, the fiber geometry itself facilitates damaging of its surface due to mechanical impact and leads to a high surface roughness, thereby often hindering commercial fibers to be used as substrates. In this article, a treatment of commercial polymer-coated glass fibers will be demonstrated that allows for the fabrication of rather flexible organic light-emitting diodes (OLEDs) with cylindrical emission characteristics. Since OLEDs rely the most on a smooth substrate, fibers undergoing the proposed treatment are applicable for other organic electronic devices such as transistors and solar cells. Finally, the technique also supports the future fabrication of organic electronics not only in smart textiles and woven electronics but also in bent surfaces, which opens a wide range of applications. PMID:28788128

Real-time imaging through strongly scattering media: seeing through turbid media, instantly

PubMed Central

Sudarsanam, Sriram; Mathew, James; Panigrahi, Swapnesh; Fade, Julien; Alouini, Mehdi; Ramachandran, Hema

2016-01-01

Numerous everyday situations like navigation, medical imaging and rescue operations require viewing through optically inhomogeneous media. This is a challenging task as photons propagate predominantly diffusively (rather than ballistically) due to random multiple scattering off the inhomogenieties. Real-time imaging with ballistic light under continuous-wave illumination is even more challenging due to the extremely weak signal, necessitating voluminous data-processing. Here we report imaging through strongly scattering media in real-time and at rates several times the critical flicker frequency of the eye, so that motion is perceived as continuous. Two factors contributed to the speedup of more than three orders of magnitude over conventional techniques - the use of a simplified algorithm enabling processing of data on the fly, and the utilisation of task and data parallelization capabilities of typical desktop computers. The extreme simplicity of the technique, and its implementation with present day low-cost technology promises its utility in a variety of devices in maritime, aerospace, rail and road transport, in medical imaging and defence. It is of equal interest to the common man and adventure sportsperson like hikers, divers, mountaineers, who frequently encounter situations requiring realtime imaging through obscuring media. As a specific example, navigation under poor visibility is examined. PMID:27114106

Secure Skyline Queries on Cloud Platform

PubMed Central

Liu, Jinfei; Yang, Juncheng; Xiong, Li; Pei, Jian

2017-01-01

Outsourcing data and computation to cloud server provides a cost-effective way to support large scale data storage and query processing. However, due to security and privacy concerns, sensitive data (e.g., medical records) need to be protected from the cloud server and other unauthorized users. One approach is to outsource encrypted data to the cloud server and have the cloud server perform query processing on the encrypted data only. It remains a challenging task to support various queries over encrypted data in a secure and efficient way such that the cloud server does not gain any knowledge about the data, query, and query result. In this paper, we study the problem of secure skyline queries over encrypted data. The skyline query is particularly important for multi-criteria decision making but also presents significant challenges due to its complex computations. We propose a fully secure skyline query protocol on data encrypted using semantically-secure encryption. As a key subroutine, we present a new secure dominance protocol, which can be also used as a building block for other queries. Finally, we provide both serial and parallelized implementations and empirically study the protocols in terms of efficiency and scalability under different parameter settings, verifying the feasibility of our proposed solutions. PMID:28883710

Implementation and benefits of advanced process control for lithography CD and overlay

NASA Astrophysics Data System (ADS)

Zavyalova, Lena; Fu, Chong-Cheng; Seligman, Gary S.; Tapp, Perry A.; Pol, Victor

2003-05-01

Due to the rapidly reduced imaging process windows and increasingly stingent device overlay requirements, sub-130 nm lithography processes are more severely impacted than ever by systamic fault. Limits on critical dimensions (CD) and overlay capability further challenge the operational effectiveness of a mix-and-match environment using multiple lithography tools, as such mode additionally consumes the available error budgets. Therefore, a focus on advanced process control (APC) methodologies is key to gaining control in the lithographic modules for critical device levels, which in turn translates to accelerated yield learning, achieving time-to-market lead, and ultimately a higher return on investment. This paper describes the implementation and unique challenges of a closed-loop CD and overlay control solution in high voume manufacturing of leading edge devices. A particular emphasis has been placed on developing a flexible APC application capable of managing a wide range of control aspects such as process and tool drifts, single and multiple lot excursions, referential overlay control, 'special lot' handling, advanced model hierarchy, and automatic model seeding. Specific integration cases, including the multiple-reticle complementary phase shift lithography process, are discussed. A continuous improvement in the overlay and CD Cpk performance as well as the rework rate has been observed through the implementation of this system, and the results are studied.

Computational characterization of ordered nanostructured surfaces

NASA Astrophysics Data System (ADS)

Mohieddin Abukhdeir, Nasser

2016-08-01

A vital and challenging task for materials researchers is to determine relationships between material characteristics and desired properties. While the measurement and assessment of material properties can be complex, quantitatively characterizing their structure is frequently a more challenging task. This issue is magnified for materials researchers in the areas of nanoscience and nanotechnology, where material structure is further complicated by phenomena such as self-assembly, collective behavior, and measurement uncertainty. Recent progress has been made in this area for both self-assembled and nanostructured surfaces due to increasing accessibility of imaging techniques at the nanoscale. In this context, recent advances in nanomaterial surface structure characterization are reviewed including the development of new theory and image processing methods.

From Nonissue to Healthcare Crisis: A Historical Review of Aging and Dying With an Intellectual and Developmental Disability.

PubMed

McGinley, Jacqueline M

2016-04-01

Individuals with intellectual and developmental disabilities are living unprecedentedly longer lives primarily due to the long-term benefits of the deinstitutionalization movement and widespread improvements in health outcomes. However, the consequences of this protracted aging process are significant, complex, and often poor not only for the individuals and their caregivers but for the mainstream healthcare community. This article will explore, utilizing a constructionist perspective, how these challenges evolved from a nonissue to an impending crisis in less than 25 years. Additionally, present-day efforts by researchers, policymakers, and practitioners to address these challenges will be explored and recommendations will be made for future directions.

A new data-processing approach to study particle motion using ultrafast X-ray tomography scanner: case study of gravitational mass flow

NASA Astrophysics Data System (ADS)

Waktola, Selam; Bieberle, Andre; Barthel, Frank; Bieberle, Martina; Hampel, Uwe; Grudzień, Krzysztof; Babout, Laurent

2018-04-01

In most industrial products, granular materials are often required to flow under gravity in various kinds of silo shapes and usually through an outlet in the bottom. There are several interrelated parameters which affect the flow, such as internal friction, bulk and packing density, hopper geometry, and material type. Due to the low-spatial resolution of electrical capacitance tomography or scanning speed limitation of standard X-ray CT systems, it is extremely challenging to measure the flow velocity and possible centrifugal effects of granular materials flow effectively. However, ROFEX (ROssendorf Fast Electron beam X-ray tomography) opens new avenues of granular flow investigation due to its very high temporal resolution. This paper aims to track particle movements and evaluate the local grain velocity during silo discharging process in the case of mass flow. The study has considered the use of the Seramis material, which can also serve as a type of tracer particles after impregnation, due to its porous nature. The presented novel image processing and analysis approach allows satisfyingly measuring individual particle velocities but also tracking their lateral movement and three-dimensional rotations.

In-network processing of joins in wireless sensor networks.

PubMed

Kang, Hyunchul

2013-03-11

The join or correlated filtering of sensor readings is one of the fundamental query operations in wireless sensor networks (WSNs). Although the join in centralized or distributed databases is a well-researched problem, join processing in WSNs has quite different characteristics and is much more difficult to perform due to the lack of statistics on sensor readings and the resource constraints of sensor nodes. Since data transmission is orders of magnitude more costly than processing at a sensor node, in-network processing of joins is essential. In this paper, the state-of-the-art techniques for join implementation in WSNs are surveyed. The requirements and challenges, join types, and components of join implementation are described. The open issues for further research are identified.

In-Network Processing of Joins in Wireless Sensor Networks

PubMed Central

Kang, Hyunchul

2013-01-01

The join or correlated filtering of sensor readings is one of the fundamental query operations in wireless sensor networks (WSNs). Although the join in centralized or distributed databases is a well-researched problem, join processing in WSNs has quite different characteristics and is much more difficult to perform due to the lack of statistics on sensor readings and the resource constraints of sensor nodes. Since data transmission is orders of magnitude more costly than processing at a sensor node, in-network processing of joins is essential. In this paper, the state-of-the-art techniques for join implementation in WSNs are surveyed. The requirements and challenges, join types, and components of join implementation are described. The open issues for further research are identified. PMID:23478603

Data-driven monitoring for stochastic systems and its application on batch process

NASA Astrophysics Data System (ADS)

Yin, Shen; Ding, Steven X.; Haghani Abandan Sari, Adel; Hao, Haiyang

2013-07-01

Batch processes are characterised by a prescribed processing of raw materials into final products for a finite duration and play an important role in many industrial sectors due to the low-volume and high-value products. Process dynamics and stochastic disturbances are inherent characteristics of batch processes, which cause monitoring of batch processes a challenging problem in practice. To solve this problem, a subspace-aided data-driven approach is presented in this article for batch process monitoring. The advantages of the proposed approach lie in its simple form and its abilities to deal with stochastic disturbances and process dynamics existing in the process. The kernel density estimation, which serves as a non-parametric way of estimating the probability density function, is utilised for threshold calculation. An industrial benchmark of fed-batch penicillin production is finally utilised to verify the effectiveness of the proposed approach.

Understanding the dispensary workflow at the Birmingham Free Clinic: a proposed framework for an informatics intervention.

PubMed

Fisher, Arielle M; Herbert, Mary I; Douglas, Gerald P

2016-02-19

The Birmingham Free Clinic (BFC) in Pittsburgh, Pennsylvania, USA is a free, walk-in clinic that serves medically uninsured populations through the use of volunteer health care providers and an on-site medication dispensary. The introduction of an electronic medical record (EMR) has improved several aspects of clinic workflow. However, pharmacists' tasks involving medication management and dispensing have become more challenging since EMR implementation due to its inability to support workflows between the medical and pharmaceutical services. To inform the design of a systematic intervention, we conducted a needs assessment study to identify workflow challenges and process inefficiencies in the dispensary. We used contextual inquiry to document the dispensary workflow and facilitate identification of critical aspects of intervention design specific to the user. Pharmacists were observed according to contextual inquiry guidelines. Graphical models were produced to aid data and process visualization. We created a list of themes describing workflow challenges and asked the pharmacists to rank them in order of significance to narrow the scope of intervention design. Three pharmacists were observed at the BFC. Observer notes were documented and analyzed to produce 13 themes outlining the primary challenges pharmacists encounter during dispensation at the BFC. The dispensary workflow is labor intensive, redundant, and inefficient when integrated with the clinical service. Observations identified inefficiencies that may benefit from the introduction of informatics interventions including: medication labeling, insufficient process notification, triple documentation, and inventory control. We propose a system for Prescription Management and General Inventory Control (RxMAGIC). RxMAGIC is a framework designed to mitigate workflow challenges and improve the processes of medication management and inventory control. While RxMAGIC is described in the context of the BFC dispensary, we believe it will be generalizable to pharmacies in other low-resource settings, both domestically and internationally.

Improving medical stores management through automation and effective communication.

PubMed

Kumar, Ashok; Cariappa, M P; Marwaha, Vishal; Sharma, Mukti; Arora, Manu

2016-01-01

Medical stores management in hospitals is a tedious and time consuming chore with limited resources tasked for the purpose and poor penetration of Information Technology. The process of automation is slow paced due to various inherent factors and is being challenged by the increasing inventory loads and escalating budgets for procurement of drugs. We carried out an indepth case study at the Medical Stores of a tertiary care health care facility. An iterative six step Quality Improvement (QI) process was implemented based on the Plan-Do-Study-Act (PDSA) cycle. The QI process was modified as per requirement to fit the medical stores management model. The results were evaluated after six months. After the implementation of QI process, 55 drugs of the medical store inventory which had expired since 2009 onwards were replaced with fresh stock by the suppliers as a result of effective communication through upgraded database management. Various pending audit objections were dropped due to the streamlined documentation and processes. Inventory management improved drastically due to automation, with disposal orders being initiated four months prior to the expiry of drugs and correct demands being generated two months prior to depletion of stocks. The monthly expense summary of drugs was now being done within ten days of the closing month. Improving communication systems within the hospital with vendor database management and reaching out to clinicians is important. Automation of inventory management requires to be simple and user-friendly, utilizing existing hardware. Physical stores monitoring is indispensable, especially due to the scattered nature of stores. Staff training and standardized documentation protocols are the other keystones for optimal medical store management.

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.

Production of Copper-Plated Beamline Bellows and Spools for LCLS-II

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

Wilson, Katherine M.; Carpenter, Brian C.; Daly, Ed

The SLAC National Accelerator Laboratory is currently constructing a major upgrade to its accelerator, the Linac Coherent Light Source II (LCLS-II). Several Department of Energy national laboratories, including the Thomas Jefferson National Accelerator Facility (JLab) and Fermi National Accelerator Laboratory (FNAL), are participating in this project. The 1.3-GHz cryomodules for this project consist of eight cavities separated by bellows (expansion joints) and spools (tube sections), which are copper plated for RF conduction. JLab is responsible for procurement of these bellows and spools, which are delivered to JLab and FNAL for assembly into cryomodules. Achieving accelerator-grade copper plating is always amore » challenge and requires careful specification of requirements and application of quality control processes. Due to the demanding technical requirements of this part, JLab implemented procurement strategies to make the process more efficient as well as provide process redundancy. This paper discusses the manufacturing challenges that were encountered and resolved, as well as the strategies that were employed to minimize the impact of any technical issues.« less

A Software Product Line Process to Develop Agents for the IoT

PubMed Central

Ayala, Inmaculada; Amor, Mercedes; Fuentes, Lidia; Troya, José M.

2015-01-01

One of the most important challenges of this decade is the Internet of Things (IoT), which aims to enable things to be connected anytime, anyplace, with anything and anyone, ideally using any path/network and any service. IoT systems are usually composed of heterogeneous and interconnected lightweight devices that support applications that are subject to change in their external environment and in the functioning of these devices. The management of the variability of these changes, autonomously, is a challenge in the development of these systems. Agents are a good option for developing self-managed IoT systems due to their distributed nature, context-awareness and self-adaptation. Our goal is to enhance the development of IoT applications using agents and software product lines (SPL). Specifically, we propose to use Self-StarMASMAS, multi-agent system) agents and to define an SPL process using the Common Variability Language. In this contribution, we propose an SPL process for Self-StarMAS, paying particular attention to agents embedded in sensor motes. PMID:26140350

Mitigating the risk of Zika virus contamination of raw materials and cell lines in the manufacture of biologicals.

PubMed

Zmurko, Joanna; Vasey, Douglas B; Donald, Claire L; Armstrong, Alison A; McKee, Marian L; Kohl, Alain; Clayton, Reginald F

2018-02-01

Ensuring the virological safety of biologicals is challenging due to the risk of viral contamination of raw materials and cell banks, and exposure during in-process handling to known and/or emerging viral pathogens. Viruses may contaminate raw materials and biologicals intended for human or veterinary use and remain undetected until appropriate testing measures are employed. The outbreak and expansive spread of the mosquito-borne flavivirus Zika virus (ZIKV) poses challenges to screening human- and animal -derived products used in the manufacture of biologicals. Here, we report the results of an in vitro study where detector cell lines were challenged with African and Asian lineages of ZIKV. We demonstrate that this pathogen is robustly detectable by in vitro assay, thereby providing assurance of detection of ZIKV, and in turn underpinning the robustness of in vitro virology assays in safety testing of biologicals.

Microfluidic Exosome Analysis toward Liquid Biopsy for Cancer.

PubMed

He, Mei; Zeng, Yong

2016-08-01

Assessment of a tumor's molecular makeup using biofluid samples, known as liquid biopsy, is a prominent research topic in precision medicine for cancer, due to its noninvasive property allowing repeat sampling for monitoring molecular changes of tumors over time. Circulating exosomes recently have been recognized as promising tumor surrogates because they deliver enriched biomarkers, such as proteins, RNAs, and DNA. However, purification and characterization of these exosomes are technically challenging. Microfluidic lab-on-a-chip technology effectively addresses these challenges owing to its inherent advantages in integration and automation of multiple functional modules, enhancing sensing performance, and expediting analysis processes. In this article, we review the state-of-the-art development of microfluidic technologies for exosome isolation and molecular characterization with emphasis on their applications toward liquid biopsy-based analysis of cancer. Finally, we share our perspectives on current challenges and future directions of microfluidic exosome analysis. © 2016 Society for Laboratory Automation and Screening.

RRAM-based hardware implementations of artificial neural networks: progress update and challenges ahead

NASA Astrophysics Data System (ADS)

Prezioso, M.; Merrikh-Bayat, F.; Chakrabarti, B.; Strukov, D.

2016-02-01

Artificial neural networks have been receiving increasing attention due to their superior performance in many information processing tasks. Typically, scaling up the size of the network results in better performance and richer functionality. However, large neural networks are challenging to implement in software and customized hardware are generally required for their practical implementations. In this work, we will discuss our group's recent efforts on the development of such custom hardware circuits, based on hybrid CMOS/memristor circuits, in particular of CMOL variety. We will start by reviewing the basics of memristive devices and of CMOL circuits. We will then discuss our recent progress towards demonstration of hybrid circuits, focusing on the experimental and theoretical results for artificial neural networks based on crossbarintegrated metal oxide memristors. We will conclude presentation with the discussion of the remaining challenges and the most pressing research needs.

Lessons in the Design and Characterization Testing of the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

NASA Technical Reports Server (NTRS)

2012-01-01

This paper focuses on some of the more challenging design processes and characterization tests of the Semi-Span Super-Sonic Transport (S4T)-Active Controls Testbed (ACT). The model was successfully tested in four entries in the National Aeronautics and Space Administration Langley Transonic Dynamics Tunnel to satisfy the goals and objectives of the Fundamental Aeronautics Program Supersonic Project Aero-Propulso-Servo-Elastic effort. Due to the complexity of the S4T-ACT, only a small sample of the technical challenges for designing and characterizing the model will be presented. Specifically, the challenges encountered in designing the model include scaling the Technology Concept Airplane to model scale, designing the model fuselage, aileron actuator, and engine pylons. Characterization tests included full model ground vibration tests, wing stiffness measurements, geometry measurements, proof load testing, and measurement of fuselage static and dynamic properties.

Data Mining for Wearable Sensors in Health Monitoring Systems: A Review of Recent Trends and Challenges

PubMed Central

Banaee, Hadi; Ahmed, Mobyen Uddin; Loutfi, Amy

2013-01-01

The past few years have witnessed an increase in the development of wearable sensors for health monitoring systems. This increase has been due to several factors such as development in sensor technology as well as directed efforts on political and stakeholder levels to promote projects which address the need for providing new methods for care given increasing challenges with an aging population. An important aspect of study in such system is how the data is treated and processed. This paper provides a recent review of the latest methods and algorithms used to analyze data from wearable sensors used for physiological monitoring of vital signs in healthcare services. In particular, the paper outlines the more common data mining tasks that have been applied such as anomaly detection, prediction and decision making when considering in particular continuous time series measurements. Moreover, the paper further details the suitability of particular data mining and machine learning methods used to process the physiological data and provides an overview of the properties of the data sets used in experimental validation. Finally, based on this literature review, a number of key challenges have been outlined for data mining methods in health monitoring systems. PMID:24351646

Data mining for wearable sensors in health monitoring systems: a review of recent trends and challenges.

PubMed

Banaee, Hadi; Ahmed, Mobyen Uddin; Loutfi, Amy

2013-12-17

The past few years have witnessed an increase in the development of wearable sensors for health monitoring systems. This increase has been due to several factors such as development in sensor technology as well as directed efforts on political and stakeholder levels to promote projects which address the need for providing new methods for care given increasing challenges with an aging population. An important aspect of study in such system is how the data is treated and processed. This paper provides a recent review of the latest methods and algorithms used to analyze data from wearable sensors used for physiological monitoring of vital signs in healthcare services. In particular, the paper outlines the more common data mining tasks that have been applied such as anomaly detection, prediction and decision making when considering in particular continuous time series measurements. Moreover, the paper further details the suitability of particular data mining and machine learning methods used to process the physiological data and provides an overview of the properties of the data sets used in experimental validation. Finally, based on this literature review, a number of key challenges have been outlined for data mining methods in health monitoring systems.

Isothermal Maxwell demon as a quantum ``sewing machine''

NASA Astrophysics Data System (ADS)

Čápek, V.

1998-04-01

A model of an open microscopic quantum system interacting with an isothermal bath and able to bind actively particles from a reservoir to their even excited bound states at the cost of the bath energy is presented. The binding (potentially important in, e.g., chain reactions-hence ``sewing'') is due to dynamic processes in a central part of the system accompanying the particle transfer. The outcome thus challenges the second law of thermodynamics.

Challenges in assessing college students' conception of duality: the case of infinity

NASA Astrophysics Data System (ADS)

Babarinsa-Ochiedike, Grace Olutayo

Interpreting students' views of infinity posits a challenge for researchers due to the dynamic nature of the conception. There is diversity and variation among students' process-object perceptions. The fluctuations between students' views however reveal an undeveloped duality conception. This study examined college students' conception of duality in understanding and representing infinity with the intent to design strategies that could guide researchers in categorizing students' views of infinity into different levels. Data for the study were collected from N=238 college students enrolled in Calculus sequence courses (Pre-Calculus, Calculus I through Calculus III) at one of the southwestern universities in the U.S. using self-report questionnaires and semi-structured individual task-based interviews. Data was triangulated using multiple measures analyzed by three independent experts using self-designed coding sheets to assess students' externalization of the duality conception of infinity. Results of this study reveal that college students' experiences in traditional Calculus sequence courses are not supportive of the development of duality conception. On the contrary, it strengthens the singularity perspective on fundamental ideas of mathematics such as infinity. The study also found that coding and assessing college students' conception of duality is a challenging and complex process due to the dynamic nature of the conception that is task-dependent and context-dependent. Practical significance of the study is that it helps to recognize misconceptions and starts addressing them so students will have a more comprehensive view of fundamental mathematical ideas as they progress through the Calculus coursework sequence. The developed duality concept development framework called Action-Process-Object-Duality (APOD) adapted from the APOS theory could guide educators and researchers as they engage in assessing students' conception of duality. The results of this study could serve as a facilitating instrument to further analyze cognitive obstacles in college students' understanding of the infinity concept.

Novel approach to engineer strains for simultaneous sugar utilization.

PubMed

Gawand, Pratish; Hyland, Patrick; Ekins, Andrew; Martin, Vincent J J; Mahadevan, Radhakrishnan

2013-11-01

Use of lignocellulosic biomass as a second generation feedstock in the biofuels industry is a pressing challenge. Among other difficulties in using lignocellulosic biomass, one major challenge is the optimal utilization of both 6-carbon (glucose) and 5-carbon (xylose) sugars by industrial microorganisms. Most industrial microorganisms preferentially utilize glucose over xylose owing to the regulatory phenomenon of carbon catabolite repression (CCR). Microorganisms that can co-utilize glucose and xylose are of considerable interest to the biofuels industry due to their ability to simplify the fermentation processes. However, elimination of CCR in microorganisms is challenging due to the multiple coordinating mechanisms involved. We report a novel algorithm, SIMUP, which finds metabolic engineering strategies to force co-utilization of two sugars, without targeting the regulatory pathways of CCR. Mutants of Escherichia coli based on SIMUP algorithm showed predicted growth phenotypes and co-utilized glucose and xylose; however, consumed the sugars slower than the wild-type. Some solutions identified by the algorithm were based on stoichiometric imbalance and were not obvious from the metabolic network topology. Furthermore, sequencing studies on the genes involved in CCR showed that the mechanism for co-utilization of the sugars could be different from previously known mechanisms. Copyright © 2013 Elsevier Inc. All rights reserved.

Environmental conditions shape the temporal pattern of investment in reproduction and survival.

PubMed

Marasco, Valeria; Boner, Winnie; Griffiths, Kate; Heidinger, Britt; Monaghan, Pat

2018-01-10

The relationship between environmental stress exposure and ageing is likely to vary with stressor severity, life-history stage and the time scale over which effects are measured. Such factors could influence whether stress exposure accelerates or slows the ageing process, but their interactions have not previously been experimentally investigated. We found that experimental exposure of zebra finches to mildly challenging environmental circumstances from young to old adulthood, which increased exposure to stress hormones, reduced breeding performance during early adulthood, but had positive effects when individuals were bred in old adulthood. This difference was not due to selective mortality, because the effects were evident within individuals, and no evidence of habituation in the response to the stressor was found. The more stressful environment had no effects on survival during young or old adulthood, but substantially improved survival during middle age. Changes in the effects at different ages could be due to the duration and nature of the challenging exposure, or to variation in coping capacity or strategy with age. These results show that living under challenging environmental circumstances can influence ageing trajectories in terms of both reproductive performance and longevity. Our results provide experimental support for the emerging idea that stress exposure needs to be optimized rather than minimized to obtain the best health outcomes. © 2018 The Author(s).

Microwave sensing for meat and fish structure evaluation

NASA Astrophysics Data System (ADS)

Clerjon, S.; Damez, J. L.

2007-04-01

Monitoring changes in muscle structure during the ageing of bovine meat and quality loss due to fish freezing are major industrial challenges. During ageing, bovine muscle becomes tender through muscle fibre deterioration, and full control of this process is essential. Conversely, degradation of fish muscle, often due to long storage or a freezing cycle, lowers quality. To improve competitiveness, and to respond to consumer quality demand, muscle structure needs to be evaluated in-line. We present here a polarimetric microwave method (10-24 GHz) consisting in free space and contact reflection coefficient measurements using a horn antenna and rectangular probes, respectively. This method is based on the measurement of dielectric properties of tissues parallel and perpendicular to muscle fibre directions. The dielectric properties of structured tissues such as muscles are anisotropic, but during processing structural disorganization reduces this anisotropy. The method is illustrated by the discrimination of fresh and frozen-thawed fish fillets and by monitoring of meat ageing.

Multi-category micro-milling tool wear monitoring with continuous hidden Markov models

NASA Astrophysics Data System (ADS)

Zhu, Kunpeng; Wong, Yoke San; Hong, Geok Soon

2009-02-01

In-process monitoring of tool conditions is important in micro-machining due to the high precision requirement and high tool wear rate. Tool condition monitoring in micro-machining poses new challenges compared to conventional machining. In this paper, a multi-category classification approach is proposed for tool flank wear state identification in micro-milling. Continuous Hidden Markov models (HMMs) are adapted for modeling of the tool wear process in micro-milling, and estimation of the tool wear state given the cutting force features. For a noise-robust approach, the HMM outputs are connected via a medium filter to minimize the tool state before entry into the next state due to high noise level. A detailed study on the selection of HMM structures for tool condition monitoring (TCM) is presented. Case studies on the tool state estimation in the micro-milling of pure copper and steel demonstrate the effectiveness and potential of these methods.

Cooperative polymerization of α-helices induced by macromolecular architecture

NASA Astrophysics Data System (ADS)

Baumgartner, Ryan; Fu, Hailin; Song, Ziyuan; Lin, Yao; Cheng, Jianjun

2017-07-01

Catalysis observed in enzymatic processes and protein polymerizations often relies on the use of supramolecular interactions and the organization of functional elements in order to gain control over the spatial and temporal elements of fundamental cellular processes. Harnessing these cooperative interactions to catalyse reactions in synthetic systems, however, remains challenging due to the difficulty in creating structurally controlled macromolecules. Here, we report a polypeptide-based macromolecule with spatially organized α-helices that can catalyse its own formation. The system consists of a linear polymeric scaffold containing a high density of initiating groups from which polypeptides are grown, forming a brush polymer. The folding of polypeptide side chains into α-helices dramatically enhances the polymerization rate due to cooperative interactions of macrodipoles between neighbouring α-helices. The parameters that affect the rate are elucidated by a two-stage kinetic model using principles from nucleation-controlled protein polymerizations; the key difference being the irreversible nature of this polymerization.

A liberation psychology approach to acculturative integration of migrant populations.

PubMed

García-Ramírez, Manuel; de la Mata, Manuel L; Paloma, Virginia; Hernández-Plaza, Sonia

2011-03-01

This paper describes an acculturative integration approach that stresses the contribution of liberation psychology. Immigrant integration is a challenge for receiving countries in the Western world due to the frequent asymmetrical and oppressive conditions suffered by newcomers in their new settlements. The cross-cultural perspective connects integration with psychological acculturation, emphasizing harmony between acquisitions of the new culture while maintaining cultural heritage, and creating opportunities for intergroup relationships. In turn, liberation psychology permits an understanding of the acculturative transition as an empowerment and self-construction process by which immigrants acquire a new vision of the world and of themselves, transforming both structural conditions and themselves. From this perspective we conceptualize acculturative integration as the process by which newcomers become an accepted part of the new society through a reflexive and evaluative process, changing their social references and position, rebuilding their social and personal resources, and achieving a new agency in coherence with their new challenges and goals. In this process, they acquire critical thinking about unequal conditions, gain capacities to respond to the inequalities, and take effective actions to confront them. We illustrate this process using the narratives of nine Moroccan women who are living in asymmetrical and oppressive local contexts in Andalusia, the southern-most region of Spain.

Addressing FinFET metrology challenges in 1X node using tilt-beam CD-SEM

NASA Astrophysics Data System (ADS)

Zhang, Xiaoxiao; Zhou, Hua; Ge, Zhenhua; Vaid, Alok; Konduparthi, Deepasree; Osorio, Carmen; Ventola, Stefano; Meir, Roi; Shoval, Ori; Kris, Roman; Adan, Ofer; Bar-Zvi, Maayan

2014-04-01

At 1X node, 3D FinFETS raise a number of new metrology challenges. Gate height and fin height are two of the most important parameters for process control. At present there is a metrology gap in inline in-die measurement of these parameters. In order to fill this metrology gap, in-column beam tilt has been developed and implemented on Applied Materials V4i+ top-down CD-SEM for height measurement. A low tilt (5°) beam and a high tilt (14°) beam have been calibrated to obtain two sets of images providing measurement of sidewall edge width to calculate height in the host. Evaluations are done with applications in both gate height and fin height. TEM correlation with R2 being 0.89 and precision of 0.81nm have been achieved on various in-die features in gate height application. Fin height measurement shows less accuracy (R2 being 0.77) and precision (1.49 nm) due to challenges brought by fin geometry, yet still promising as first attempt. Sensitivity to DOE offset, die-to-die and in-die variation is demonstrated in both gate height and fin height. Process defect is successfully captured from inline wafers with gate height measurement implemented in production. This is the first successful demonstration of inline in-die gate height measurement for 14nm FinFET process control.

Interference Alignment With Partial CSI Feedback in MIMO Cellular Networks

NASA Astrophysics Data System (ADS)

Rao, Xiongbin; Lau, Vincent K. N.

2014-04-01

Interference alignment (IA) is a linear precoding strategy that can achieve optimal capacity scaling at high SNR in interference networks. However, most existing IA designs require full channel state information (CSI) at the transmitters, which would lead to significant CSI signaling overhead. There are two techniques, namely CSI quantization and CSI feedback filtering, to reduce the CSI feedback overhead. In this paper, we consider IA processing with CSI feedback filtering in MIMO cellular networks. We introduce a novel metric, namely the feedback dimension, to quantify the first order CSI feedback cost associated with the CSI feedback filtering. The CSI feedback filtering poses several important challenges in IA processing. First, there is a hidden partial CSI knowledge constraint in IA precoder design which cannot be handled using conventional IA design methodology. Furthermore, existing results on the feasibility conditions of IA cannot be applied due to the partial CSI knowledge. Finally, it is very challenging to find out how much CSI feedback is actually needed to support IA processing. We shall address the above challenges and propose a new IA feasibility condition under partial CSIT knowledge in MIMO cellular networks. Based on this, we consider the CSI feedback profile design subject to the degrees of freedom requirements, and we derive closed-form trade-off results between the CSI feedback cost and IA performance in MIMO cellular networks.

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

Mouton, S.; Ledoux, Y.; Teissandier, D.

A key challenge for the future is to reduce drastically the human impact on the environment. In the aeronautic field, this challenge aims at optimizing the design of the aircraft to decrease the global mass. This reduction leads to the optimization of every part constitutive of the plane. This operation is even more delicate when the used material is composite material. In this case, it is necessary to find a compromise between the strength, the mass and the manufacturing cost of the component. Due to these different kinds of design constraints it is necessary to assist engineer with decision supportmore » system to determine feasible solutions. In this paper, an approach is proposed based on the coupling of the different key characteristics of the design process and on the consideration of the failure risk of the component. The originality of this work is that the manufacturing deviations due to the RTM process are integrated in the simulation of the assembly process. Two kinds of deviations are identified: volume impregnation (injection phase of RTM process) and geometrical deviations (curing and cooling phases). The quantification of these deviations and the related failure risk calculation is based on finite element simulations (Pam RTM registered and Samcef registered softwares). The use of genetic algorithm allows to estimate the impact of the design choices and their consequences on the failure risk of the component. The main focus of the paper is the optimization of tool design. In the framework of decision support systems, the failure risk calculation is used for making the comparison of possible industrialization alternatives. It is proposed to apply this method on a particular part of the airplane structure: a spar unit made of carbon fiber/epoxy composite.« less

A Fundamental Study of Inorganic Clathrate and Other Open-Framework Materials

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

Nolas, George

Due to formidable synthetic challenges, many materials of scientific and technological interest are first obtained as microcrystalline powders. High purity, high yield processing techniques are often lacking and thus care must be taken in interpretation of the observed structural, chemical, and physical properties of powder or polycrystalline materials, which can be strongly influenced by extrinsic properties. Furthermore, the preparation of high-quality single crystals for many materials by traditional techniques can be especially challenging in cases where the elemental constituents have greatly differing melting points and/or vapor pressures, when the desired compound is thermodynamically metastable, or where growth with participation ofmore » the melt is generally not possible. New processing techniques are therefore imperative in order to investigate the intrinsic properties of these materials and elucidate their fundamental physical properties. Intermetallic clathrates constitute one such class of materials. The complex crystal structures of intermetallic clathrates are characterized by mainly group 14 host frameworks encapsulating guest-ions in polyhedral cages. The unique features of clathrate structures are intimately related to their physical properties, offering ideal systems for the study of structure-property relationships in crystalline solids. Moreover, intermetallic clathrates are being actively investigated due to their potential for application in thermoelectrics, photovoltaics and opto-electronics, superconductivity, and magnetocaloric technologies. We have developed different processing techniques in order to synthesize phase-pure high yield clathrates reproducibly, as well as grow single crystals for the first time. We also employed these techniques to synthesize new “open-framework” compounds. These advances in materials processing and crystal growth allowed for the investigation of the physical properties of a variety of different clathrate compositions for the first time.« less

Challenges of caring for children with mental disorders: Experiences and views of caregivers attending the outpatient clinic at Muhimbili National Hospital, Dar es Salaam - Tanzania.

PubMed

Ambikile, Joel Semel; Outwater, Anne

2012-07-05

It is estimated that world-wide up to 20 % of children suffer from debilitating mental illness. Mental disorders that pose a significant concern include learning disorders, hyperkinetic disorders (ADHD), depression, psychosis, pervasive development disorders, attachment disorders, anxiety disorders, conduct disorder, substance abuse and eating disorders. Living with such children can be very stressful for caregivers in the family. Therefore, determination of challenges of living with these children is important in the process of finding ways to help or support caregivers to provide proper care for their children. The purpose of this study was to explore the psychological and emotional, social, and economic challenges that parents or guardians experience when caring for mentally ill children and what they do to address or deal with them. A qualitative study design using in-depth interviews and focus group discussions was applied. The study was conducted at the psychiatric unit of Muhimbili National Hospital in Tanzania. Two focus groups discussions (FGDs) and 8 in-depth interviews were conducted with caregivers who attended the psychiatric clinic with their children. Data analysis was done using content analysis. The study revealed psychological and emotional, social, and economic challenges caregivers endure while living with mentally ill children. Psychological and emotional challenges included being stressed by caring tasks and having worries about the present and future life of their children. They had feelings of sadness, and inner pain or bitterness due to the disturbing behaviour of the children. They also experienced some communication problems with their children due to their inability to talk. Social challenges were inadequate social services for their children, stigma, burden of caring task, lack of public awareness of mental illness, lack of social support, and problems with social life. The economic challenges were poverty, child care interfering with various income generating activities in the family, and extra expenses associated with the child's illness. Caregivers of mentally ill children experience various psychological and emotional, social, and economic challenges. Professional assistance, public awareness of mental illnesses in children, social support by the government, private sector, and non-governmental organizations (NGOs) are important in addressing these challenges.

Use of near-infrared spectroscopy (NIRs) in the biopharmaceutical industry for real-time determination of critical process parameters and integration of advanced feedback control strategies using MIDUS control.

PubMed

Vann, Lucas; Sheppard, John

2017-12-01

Control of biopharmaceutical processes is critical to achieve consistent product quality. The most challenging unit operation to control is cell growth in bioreactors due to the exquisitely sensitive and complex nature of the cells that are converting raw materials into new cells and products. Current monitoring capabilities are increasing, however, the main challenge is now becoming the ability to use the data generated in an effective manner. There are a number of contributors to this challenge including integration of different monitoring systems as well as the functionality to perform data analytics in real-time to generate process knowledge and understanding. In addition, there is a lack of ability to easily generate strategies and close the loop to feedback into the process for advanced process control (APC). The current research aims to demonstrate the use of advanced monitoring tools along with data analytics to generate process understanding in an Escherichia coli fermentation process. NIR spectroscopy was used to measure glucose and critical amino acids in real-time to help in determining the root cause of failures associated with different lots of yeast extract. First, scale-down of the process was required to execute a simple design of experiment, followed by scale-up to build NIR models as well as soft sensors for advanced process control. In addition, the research demonstrates the potential for a novel platform technology that enables manufacturers to consistently achieve "goldenbatch" performance through monitoring, integration, data analytics, understanding, strategy design and control (MIDUS control). MIDUS control was employed to increase batch-to-batch consistency in final product titers, decrease the coefficient of variability from 8.49 to 1.16%, predict possible exhaust filter failures and close the loop to prevent their occurrence and avoid lost batches.

Incorporation of negative rules and evolution of a fuzzy controller for yeast fermentation process.

PubMed

Birle, Stephan; Hussein, Mohamed Ahmed; Becker, Thomas

2016-08-01

The control of bioprocesses can be very challenging due to the fact that these kinds of processes are highly affected by various sources of uncertainty like the intrinsic behavior of the used microorganisms. Due to the reason that these kinds of process uncertainties are not directly measureable in most cases, the overall control is either done manually because of the experience of the operator or intelligent expert systems are applied, e.g., on the basis of fuzzy logic theory. In the latter case, however, the control concept is mainly represented by using merely positive rules, e.g., "If A then do B". As this is not straightforward with respect to the semantics of the human decision-making process that also includes negative experience in form of constraints or prohibitions, the incorporation of negative rules for process control based on fuzzy logic is emphasized. In this work, an approach of fuzzy logic control of the yeast propagation process based on a combination of positive and negative rules is presented. The process is guided along a reference trajectory for yeast cell concentration by alternating the process temperature. The incorporation of negative rules leads to a much more stable and accurate control of the process as the root mean squared error of reference trajectory and system response could be reduced by an average of 62.8 % compared to the controller using only positive rules.

Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production

PubMed Central

Patel, Vinay R.; Dumancas, Gerard G.; Kasi Viswanath, Lakshmi C.; Maples, Randall; Subong, Bryan John J.

2016-01-01

Castor oil, produced from castor beans, has long been considered to be of important commercial value primarily for the manufacturing of soaps, lubricants, and coatings, among others. Global castor oil production is concentrated primarily in a small geographic region of Gujarat in Western India. This region is favorable due to its labor-intensive cultivation method and subtropical climate conditions. Entrepreneurs and castor processors in the United States and South America also cultivate castor beans but are faced with the challenge of achieving high castor oil production efficiency, as well as obtaining the desired oil quality. In this manuscript, we provide a detailed analysis of novel processing methods involved in castor oil production. We discuss novel processing methods by explaining specific processing parameters involved in castor oil production. PMID:27656091

Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production.

PubMed

Patel, Vinay R; Dumancas, Gerard G; Kasi Viswanath, Lakshmi C; Maples, Randall; Subong, Bryan John J

2016-01-01

Castor oil, produced from castor beans, has long been considered to be of important commercial value primarily for the manufacturing of soaps, lubricants, and coatings, among others. Global castor oil production is concentrated primarily in a small geographic region of Gujarat in Western India. This region is favorable due to its labor-intensive cultivation method and subtropical climate conditions. Entrepreneurs and castor processors in the United States and South America also cultivate castor beans but are faced with the challenge of achieving high castor oil production efficiency, as well as obtaining the desired oil quality. In this manuscript, we provide a detailed analysis of novel processing methods involved in castor oil production. We discuss novel processing methods by explaining specific processing parameters involved in castor oil production.

Accurate, fast, and secure biometric fingerprint recognition system utilizing sensor fusion of fingerprint patterns

NASA Astrophysics Data System (ADS)

El-Saba, Aed; Alsharif, Salim; Jagapathi, Rajendarreddy

2011-04-01

Fingerprint recognition is one of the first techniques used for automatically identifying people and today it is still one of the most popular and effective biometric techniques. With this increase in fingerprint biometric uses, issues related to accuracy, security and processing time are major challenges facing the fingerprint recognition systems. Previous work has shown that polarization enhancementencoding of fingerprint patterns increase the accuracy and security of fingerprint systems without burdening the processing time. This is mainly due to the fact that polarization enhancementencoding is inherently a hardware process and does not have detrimental time delay effect on the overall process. Unpolarized images, however, posses a high visual contrast and when fused (without digital enhancement) properly with polarized ones, is shown to increase the recognition accuracy and security of the biometric system without any significant processing time delay.

Exosomes as therapeutic drug carriers and delivery vehicles across biological membranes: current perspectives and future challenges.

PubMed

Ha, Dinh; Yang, Ningning; Nadithe, Venkatareddy

2016-07-01

Exosomes are small intracellular membrane-based vesicles with different compositions that are involved in several biological and pathological processes. The exploitation of exosomes as drug delivery vehicles offers important advantages compared to other nanoparticulate drug delivery systems such as liposomes and polymeric nanoparticles; exosomes are non-immunogenic in nature due to similar composition as body׳s own cells. In this article, the origin and structure of exosomes as well as their biological functions are outlined. We will then focus on specific applications of exosomes as drug delivery systems in pharmaceutical drug development. An overview of the advantages and challenges faced when using exosomes as a pharmaceutical drug delivery vehicles will also be discussed.

Procedural Challenges In International Collaborative Research

PubMed Central

Loo, Kek Khee

2009-01-01

There is tremendous promise for a rewarding experience in an international research project due to the collaboration, mutual learning and cultural bridging that intrinsically occur. However, knowledge of the procedural requirements for international research is not widely disseminated to investigators who may not have been involved in the administration of a federal grant with a foreign component. The purpose of this article is to highlight the major challenges in administrative, procedural and equipment management aspects of grant implementation when federal funding is involved in international collaborative research. It is hoped that awareness of these difficulties and demystification of the process for future investigators can minimize the potential encumbrances in a rewarding journey towards realizing the scientific goals in an international collaborative research project. PMID:19574522

Nano-plasmonic exosome diagnostics

PubMed Central

Im, Hyungsoon; Shao, Huilin; Weissleder, Ralph; Castro, Cesar M.; Lee, Hakho

2015-01-01

Exosomes have emerged as a promising biomarker. These vesicles abound in biofluids and harbor molecular constituents from their parent cells, thereby offering a minimally-invasive avenue for molecular analyses. Despite such clinical potential, routine exosomal analysis, particularly the protein assay, remains challenging, due to requirements for large sample volumes and extensive processing. We have been developing miniaturized systems to facilitate clinical exosome studies. These systems can be categorized into two components: microfluidics for sample preparation and analytical tools for protein analyses. In this report, we review a new assay platform, nano-plasmonic exosome (nPLEX), in which sensing is based on surface plasmon resonance to achieve label-free exosome detection. Looking forward, we also discuss some potential challenges and improvements in exosome studies. PMID:25936957

HSPF Modeling for Compliance and Enforcement: An Urban Case Study

NASA Astrophysics Data System (ADS)

Marshalonis, D.

2017-12-01

Stormwater runoff is one of the most significant challenges to water quality facing surface waters globally. In the United States, the Environmental Protection Agency (EPA) regulates stormwater flows through its National Pollutant Discharge Elimination System (NPDES) program permits. When egregious violations occur, EPA may develop its case and prove those violations through the legal dispute process. However, evidence in stormwater-related cases is ephemeral, difficult to collect due to unpredictable weather dynamics, and there are usually no witnesses. The work presented here illustrates an approach EPA takes for certain wet weather cases: introduce results from hydrologic and hydraulic models as evidence to meet legal burden of proof standards. The challenges and opportunities of using models in stormwater discharge modeling are highlighted.

Trajectory design for Saturnian Ocean Worlds orbiters using multidimensional Poincaré maps

NASA Astrophysics Data System (ADS)

Davis, Diane Craig; Phillips, Sean M.; McCarthy, Brian P.

2018-02-01

Missions based on low-energy orbits in the vicinity of planetary moons, such as Titan or Enceladus, involve significant end-to-end trajectory design challenges due to the gravitational effects of the distant larger primary. To address these challenges, the current investigation focuses on the visualization and use of multidimensional Poincaré maps to perform preliminary design of orbits with significant out-of-plane components, including orbits that provide polar coverage. Poincaré maps facilitate the identification of families of solutions to a given orbit problem and provide the ability to easily respond to changing inputs and requirements. A visual-based design process highlights a variety of trajectory options near Saturn's ocean worlds, including both moon-centered orbits and libration point orbits.

Shamba Maisha: Pilot agricultural intervention for food security and HIV health outcomes in Kenya: design, methods, baseline results and process evaluation of a cluster-randomized controlled trial.

PubMed

Cohen, Craig R; Steinfeld, Rachel L; Weke, Elly; Bukusi, Elizabeth A; Hatcher, Abigail M; Shiboski, Stephen; Rheingans, Richard; Scow, Kate M; Butler, Lisa M; Otieno, Phelgona; Dworkin, Shari L; Weiser, Sheri D

2015-01-01

Despite advances in treatment of people living with HIV, morbidity and mortality remains unacceptably high in sub-Saharan Africa, largely due to parallel epidemics of poverty and food insecurity. We conducted a pilot cluster randomized controlled trial (RCT) of a multisectoral agricultural and microfinance intervention (entitled Shamba Maisha) designed to improve food security, household wealth, HIV clinical outcomes and women's empowerment. The intervention was carried out at two HIV clinics in Kenya, one randomized to the intervention arm and one to the control arm. HIV-infected patients >18 years, on antiretroviral therapy, with moderate/severe food insecurity and/or body mass index (BMI) <18.5, and access to land and surface water were eligible for enrollment. The intervention included: 1) a microfinance loan (~$150) to purchase the farming commodities, 2) a micro-irrigation pump, seeds, and fertilizer, and 3) trainings in sustainable agricultural practices and financial literacy. Enrollment of 140 participants took four months, and the screening-to-enrollment ratio was similar between arms. We followed participants for 12 months and conducted structured questionnaires. We also conducted a process evaluation with participants and stakeholders 3-5 months after study start and at study end. Baseline results revealed that participants at the two sites were similar in age, gender and marital status. A greater proportion of participants at the intervention site had a low BMI in comparison to participants at the control site (18% vs. 7%, p = 0.054). While median CD4 count was similar between arms, a greater proportion of participants enrolled at the intervention arm had a detectable HIV viral load compared with control participants (49% vs. 28%, respectively, p < 0.010). Process evaluation findings suggested that Shamba Maisha had high acceptability in recruitment, delivered strong agricultural and financial training, and led to labor saving due to use of the water pump. Implementation challenges included participant concerns about repaying loans, agricultural challenges due to weather patterns, and a challenging partnership with the microfinance institution. We expect the results from this pilot study to provide useful data on the impacts of livelihood interventions and will help in the design of a definitive cluster RCT. This trial is registered at ClinicalTrials.gov, NCT01548599.

Stress Physiology in Infancy and Early Childhood: Cortisol Flexibility, Attunement and Coordination.

PubMed

Atkinson, L; Jamieson, B; Khoury, J; Ludmer, J; Gonzalez, A

2016-08-01

Research on stress physiology in infancy has assumed increasing importance due to its lifelong implications. In this review, we focus on measurement of hypothalamic-pituitary-adrenal (HPA) function, in particular, and on complementary autonomic processes. We suggest that the measure of HPA function has been overly exclusive, focusing on individual reactivity to single, pragmatically selected laboratory challenges. We advocate use of multiple, strategically chosen challenges and within-subject designs. By administering one challenge that typically does not provoke reactivity and another that does, it is possible to represent allostatic load in terms of "flexibility," the capacity to titrate response to challenge. We also recommend assessing infant reactivity in the context of the primary caregiver's physiological function. Infant-mother "attunement" is central to developmental psychology, permeating diverse developmental domains with varied consequences. A review of adrenocortical attunement suggests that attunement is a reliable process, manifest across varied populations. However, attunement appears stronger in the context of more highly stressful circumstances, such that administration of multiple, selected challenges may help evaluate the degree to which individuals titrate attunement to challenge and determine the correlates of this differential attunement. Finally, we advocate studying the "coordination" of HPA function with other aspects of stress physiology and variation in the degree of this coordination. The use of multiple stressors is important here because each stress system is differentially sensitive to different types of challenge. Therefore, use of single stressors in between-subject designs impedes full recognition of the role played by each system. Overall, we recommend measure of flexibility, attunement, and coordination in the context of multiple challenges to capture allostasis in environmental and physiological context. The simultaneous use of such inclusive and integrative metrics may yield more reliable findings than has hitherto been the case. The interrelation of these metrics can be understood in the context of the adaptive calibration model.. © 2016 British Society for Neuroendocrinology.

Investigating the Hurst-Kolmogorov behavior of Sicily's climatological time series

NASA Astrophysics Data System (ADS)

Giglioni, M.; Lombardo, F.; Mineo, C.

2017-07-01

There is evidence that many geophysical processesexhibit long-term persistence(LTP, also calledlong-range dependence). Overlooking this type of behaviorcan lead to wrong inferences and false claims about the properties of processes studied in the fields of hydrology, hydraulics, meteorology, and engineering. In this light, the present study investigates the statistical properties of precipitation and temperature datasets from Sicily (Italy),in order to analyzethe presence of LTP. The case study region(i.e., the largest island in the Mediterranean)is characterized by typical Mediterranean climate with mild winter and severe drought conditions in summer time. The latter have become one of the most challenging issuesall over the Mediterranean region due to the growth of population, contamination of water supplies, and expansion of agricultural, energy and industrial sectors. The severity and duration of the drought eventsare clearly influenced by the presence of LTP in precipitation and temperature processes. Improving understanding ofsuch phenomenonis therefore central to new research challenges related to the estimation and management of water resources.

Fiber Bragg Grating Sensors toward Structural Health Monitoring in Composite Materials: Challenges and Solutions

PubMed Central

Kinet, Damien; Mégret, Patrice; Goossen, Keith W.; Qiu, Liang; Heider, Dirk; Caucheteur, Christophe

2014-01-01

Nowadays, smart composite materials embed miniaturized sensors for structural health monitoring (SHM) in order to mitigate the risk of failure due to an overload or to unwanted inhomogeneity resulting from the fabrication process. Optical fiber sensors, and more particularly fiber Bragg grating (FBG) sensors, outperform traditional sensor technologies, as they are lightweight, small in size and offer convenient multiplexing capabilities with remote operation. They have thus been extensively associated to composite materials to study their behavior for further SHM purposes. This paper reviews the main challenges arising from the use of FBGs in composite materials. The focus will be made on issues related to temperature-strain discrimination, demodulation of the amplitude spectrum during and after the curing process as well as connection between the embedded optical fibers and the surroundings. The main strategies developed in each of these three topics will be summarized and compared, demonstrating the large progress that has been made in this field in the past few years. PMID:24763215

Pandoraea sp. B-6 assists the deep eutectic solvent pretreatment of rice straw via promoting lignin depolymerization.

PubMed

Liu, Dan; Yan, Xu; Zhuo, Shengnan; Si, Mengying; Liu, Mingren; Wang, Sheng; Ren, Lili; Chai, Liyuan; Shi, Yan

2018-06-01

Lignin depolymerization is a challenging process in biorefinery due to the recalcitrant and complex structure of lignin. This challenge was herein addressed via elaborating a new strategy of combining the bacterial strain Pandoraea sp. B-6 (hereafter B-6) with a deep eutectic solvent (DES) to pretreat rice straw (RS). In this approach, DES effectively depolymerized lignin yet easily caused sugar loss under severe conditions. B-6 not only overcame the obstacle of lignin droplets, but also significantly improved enzymatic digestibility. After B-6 assisted DES pretreatment, the reducing sugar yield increases by 0.3-1.5 times over DES pretreatment and 0.9-3.1 times over the untreated RS. Furthermore, a "cornhusking" mechanism explaining the improvement of the enzymatic digestibility by B-6 was suggested based on physicochemical characterizations of the untreated and pretreated RS. The findings provided a comprehensive perspective to establish a DES-microbial process for lignocellulose pretreatment. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enabling X-ray free electron laser crystallography for challenging biological systems from a limited number of crystals

DOE PAGES

Uervirojnangkoorn, Monarin; Zeldin, Oliver B.; Lyubimov, Artem Y.; ...

2015-03-17

There is considerable potential for X-ray free electron lasers (XFELs) to enable determination of macromolecular crystal structures that are difficult to solve using current synchrotron sources. Prior XFEL studies often involved the collection of thousands to millions of diffraction images, in part due to limitations of data processing methods. We implemented a data processing system based on classical post-refinement techniques, adapted to specific properties of XFEL diffraction data. When applied to XFEL data from three different proteins collected using various sample delivery systems and XFEL beam parameters, our method improved the quality of the diffraction data as well as themore » resulting refined atomic models and electron density maps. Moreover, the number of observations for a reflection necessary to assemble an accurate data set could be reduced to a few observations. In conclusion, these developments will help expand the applicability of XFEL crystallography to challenging biological systems, including cases where sample is limited.« less

Enabling X-ray free electron laser crystallography for challenging biological systems from a limited number of crystals

DOE PAGES

Uervirojnangkoorn, Monarin; Zeldin, Oliver B.; Lyubimov, Artem Y.; ...

2015-03-17

There is considerable potential for X-ray free electron lasers (XFELs) to enable determination of macromolecular crystal structures that are difficult to solve using current synchrotron sources. Prior XFEL studies often involved the collection of thousands to millions of diffraction images, in part due to limitations of data processing methods. We implemented a data processing system based on classical post-refinement techniques, adapted to specific properties of XFEL diffraction data. When applied to XFEL data from three different proteins collected using various sample delivery systems and XFEL beam parameters, our method improved the quality of the diffraction data as well as themore » resulting refined atomic models and electron density maps. Moreover, the number of observations for a reflection necessary to assemble an accurate data set could be reduced to a few observations. These developments will help expand the applicability of XFEL crystallography to challenging biological systems, including cases where sample is limited.« less

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).

A scheme to calculate higher-order homogenization as applied to micro-acoustic boundary value problems

NASA Astrophysics Data System (ADS)

Vagh, Hardik A.; Baghai-Wadji, Alireza

2008-12-01

Current technological challenges in materials science and high-tech device industry require the solution of boundary value problems (BVPs) involving regions of various scales, e.g. multiple thin layers, fibre-reinforced composites, and nano/micro pores. In most cases straightforward application of standard variational techniques to BVPs of practical relevance necessarily leads to unsatisfactorily ill-conditioned analytical and/or numerical results. To remedy the computational challenges associated with sub-sectional heterogeneities various sophisticated homogenization techniques need to be employed. Homogenization refers to the systematic process of smoothing out the sub-structural heterogeneities, leading to the determination of effective constitutive coefficients. Ordinarily, homogenization involves a sophisticated averaging and asymptotic order analysis to obtain solutions. In the majority of the cases only zero-order terms are constructed due to the complexity of the processes involved. In this paper we propose a constructive scheme for obtaining homogenized solutions involving higher order terms, and thus, guaranteeing higher accuracy and greater robustness of the numerical results. We present

Enabling X-ray free electron laser crystallography for challenging biological systems from a limited number of crystals

PubMed Central

Uervirojnangkoorn, Monarin; Zeldin, Oliver B; Lyubimov, Artem Y; Hattne, Johan; Brewster, Aaron S; Sauter, Nicholas K; Brunger, Axel T; Weis, William I

2015-01-01

There is considerable potential for X-ray free electron lasers (XFELs) to enable determination of macromolecular crystal structures that are difficult to solve using current synchrotron sources. Prior XFEL studies often involved the collection of thousands to millions of diffraction images, in part due to limitations of data processing methods. We implemented a data processing system based on classical post-refinement techniques, adapted to specific properties of XFEL diffraction data. When applied to XFEL data from three different proteins collected using various sample delivery systems and XFEL beam parameters, our method improved the quality of the diffraction data as well as the resulting refined atomic models and electron density maps. Moreover, the number of observations for a reflection necessary to assemble an accurate data set could be reduced to a few observations. These developments will help expand the applicability of XFEL crystallography to challenging biological systems, including cases where sample is limited. DOI: http://dx.doi.org/10.7554/eLife.05421.001 PMID:25781634

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.

Diversifying bio-petro fuel sources for future energy sustainability and its challenges

NASA Astrophysics Data System (ADS)

Othman, M. R.; Helwani, Z.; Idris, I.

2018-04-01

Petroleum has been important in the energy industry since 19th century when the refining of paraffin from crude oil began. The industry recently appears to be in a downtown and fragile moment despite the price of oil is slowly rising. Renewable alternatives such as biofuels have gained increasing traction while petroleum fuel seemingly concedes to bio-fuels due to the rising public concern on the environment and stricter emission regulations. To be a strategic fuel in the energy security matrix, both fossil and bio-fuels options should be considered. However, the use of bio-fuels to achieve a degree of carbon neutrality is not without challenges. Among the challenges are land development and socio-political issue, carbon neutrality due to ILUC, high 2G bio-fuel feedstock and production cost, competing technology from electric vehicles and the impending fourth industrial revolution, NOx emissions and variation in biodiesel quality. This paper briefly reviews the potential of fuels source diversification and the challenges and how they can raise up to the challenges in order to be sustainable and attractive. In order to achieve this objective, first carbon credit through carbon trading needs to continue to stabilize the energy price. Second, 1G bio-fuel needs to forgo the use of natural, peat forest, rubber estate since these are an effective carbon sink and oxygen source. Third, advanced bio-fuels with high yield, process economics and sustainability need to be innovated. Fourth, the quality and standard bio-fuel that reduces NOx emission need to be improved. Finally and most importantly, carbon capture technology needs to be deployed immediately in fossil fuel power plants.

Laser Processed Silver Nanowire Network Transparent Electrodes for Novel Electronic Devices

NASA Astrophysics Data System (ADS)

Spechler, Joshua Allen

Silver nanowire network transparent conducting layers are poised to make headway into a space previously dominated by transparent conducting oxides due to the promise of a flexible, scaleable, lab-atmosphere processable alternative. However, there are many challenges standing in the way between research scale use and consumer technology scale adaptation of this technology. In this thesis we will explore many, and overcome a few of these challenges. We will address the poor conductivity at the narrow nanowire-nanowire junction points in the network by developing a laser based process to weld nanowires together on a microscopic scale. We address the need for a comparative metric for transparent conductors in general, by taking a device level rather than a component level view of these layers. We also address the mechanical, physical, and thermal limitations to the silver nanowire networks by making composites from materials including a colorless polyimide and titania sol-gel. Additionally, we verify our findings by integrating these processes into devices. Studying a hybrid organic/inorganic heterojunction photovoltaic device we show the benefits of a laser processed electrode. Green phosphorescent organic light emitting diodes fabricated on a solution phase processed silver nanowire based electrode show favorable device metrics compared to a conductive oxide electrode based control. The work in this thesis is intended to push the adoption of silver nanowire networks to further allow new device architectures, and thereby new device applications.

Recent Advances of Rare-Earth Ion Doped Luminescent Nanomaterials in Perovskite Solar Cells.

PubMed

Qiao, Yu; Li, Shuhan; Liu, Wenhui; Ran, Meiqing; Lu, Haifei; Yang, Yingping

2018-01-15

Organic-inorganic lead halide based perovskite solar cells have received broad interest due to their merits of low fabrication cost, a low temperature solution process, and high energy conversion efficiencies. Rare-earth (RE) ion doped nanomaterials can be used in perovskite solar cells to expand the range of absorption spectra and improve the stability due to its upconversion and downconversion effect. This article reviews recent progress in using RE-ion-doped nanomaterials in mesoporous electrodes, perovskite active layers, and as an external function layer of perovskite solar cells. Finally, we discuss the challenges facing the effective use of RE-ion-doped nanomaterials in perovskite solar cells and present some prospects for future research.

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

Kamran, Mudassar, E-mail: kamranm@mir.wustl.edu; Fowler, Kathryn J., E-mail: fowlerk@mir.wustl.edu; Mellnick, Vincent M., E-mail: mellnickv@mir.wustl.edu

Primary aortic neoplasms are rare. Aortic sarcoma arising after endovascular aneurysm repair (EVAR) is a scarce subset of primary aortic malignancies, reports of which are infrequent in the published literature. The diagnosis of aortic sarcoma is challenging due to its non-specific clinical presentation, and the prognosis is poor due to delayed diagnosis, rapid proliferation, and propensity for metastasis. Post-EVAR, aortic sarcomas may mimic other more common aortic processes on surveillance imaging. Radiologists are rarely knowledgeable about this rare entity for which multimodality imaging and awareness are invaluable in early diagnosis. A series of three pathologically confirmed cases are presented tomore » display the multimodality imaging features and clinical presentations of aortic sarcoma arising after EVAR.« less

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.

Physics and Women: A Challenge Being Successfully Met in Cuba

NASA Astrophysics Data System (ADS)

Arias de Fuentes, Olimpia

The history of physics in Cuba, like all the country's educational and scientific development, cannot be understood without taking into account its close relationship with the social changes that took place in Cuba during the five decades elapsed since 1959. This should include due consideration to the role played by women in this process, all the more since the link between science and gender is now generally regarded as a subject of growing special interest

Improving medical stores management through automation and effective communication

PubMed Central

Kumar, Ashok; Cariappa, M.P.; Marwaha, Vishal; Sharma, Mukti; Arora, Manu

2016-01-01

Background Medical stores management in hospitals is a tedious and time consuming chore with limited resources tasked for the purpose and poor penetration of Information Technology. The process of automation is slow paced due to various inherent factors and is being challenged by the increasing inventory loads and escalating budgets for procurement of drugs. Methods We carried out an indepth case study at the Medical Stores of a tertiary care health care facility. An iterative six step Quality Improvement (QI) process was implemented based on the Plan–Do–Study–Act (PDSA) cycle. The QI process was modified as per requirement to fit the medical stores management model. The results were evaluated after six months. Results After the implementation of QI process, 55 drugs of the medical store inventory which had expired since 2009 onwards were replaced with fresh stock by the suppliers as a result of effective communication through upgraded database management. Various pending audit objections were dropped due to the streamlined documentation and processes. Inventory management improved drastically due to automation, with disposal orders being initiated four months prior to the expiry of drugs and correct demands being generated two months prior to depletion of stocks. The monthly expense summary of drugs was now being done within ten days of the closing month. Conclusion Improving communication systems within the hospital with vendor database management and reaching out to clinicians is important. Automation of inventory management requires to be simple and user-friendly, utilizing existing hardware. Physical stores monitoring is indispensable, especially due to the scattered nature of stores. Staff training and standardized documentation protocols are the other keystones for optimal medical store management. PMID:26900225

Advantages and challenges of the spray-drying technology for the production of pure drug particles and drug-loaded polymeric carriers.

PubMed

Sosnik, Alejandro; Seremeta, Katia P

2015-09-01

Spray-drying is a rapid, continuous, cost-effective, reproducible and scalable process for the production of dry powders from a fluid material by atomization through an atomizer into a hot drying gas medium, usually air. Often spray-drying is considered only a dehydration process, though it also can be used for the encapsulation of hydrophilic and hydrophobic active compounds within different carriers without substantial thermal degradation, even of heat-sensitive substances due to fast drying (seconds or milliseconds) and relatively short exposure time to heat. The solid particles obtained present relatively narrow size distribution at the submicron-to-micron scale. Generally, the yield% of spray-drying at laboratory scale with conventional spray-dryers is not optimal (20-70%) due to the loss of product in the walls of the drying chamber and the low capacity of the cyclone to separate fine particles (<2 μm). Aiming to overcome this crucial drawback in early development stages, new devices that enable the production of submicron particles with high yield, even for small sample amounts, have been introduced into the market. This review describes the most outstanding advantages and challenges of the spray-drying method for the production of pure drug particles and drug-loaded polymeric particles and discusses the potential of this technique and the more advanced equipment to pave the way toward reproducible and scalable processes that are critical to the bench-to-bedside translation of innovative pharmaceutical products. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

Monitoring of Students' Interaction in Online Learning Settings by Structural Network Analysis and Indicators.

PubMed

Ammenwerth, Elske; Hackl, Werner O

2017-01-01

Learning as a constructive process works best in interaction with other learners. Support of social interaction processes is a particular challenge within online learning settings due to the spatial and temporal distribution of participants. It should thus be carefully monitored. We present structural network analysis and related indicators to analyse and visualize interaction patterns of participants in online learning settings. We validate this approach in two online courses and show how the visualization helps to monitor interaction and to identify activity profiles of learners. Structural network analysis is a feasible approach for an analysis of the intensity and direction of interaction in online learning settings.

Galileo spacecraft integration - International cooperation on a planetary mission in the Shuttle era

NASA Technical Reports Server (NTRS)

Spehalski, R. J.

1983-01-01

The Galileo mission is designed to greatly expand scientific knowledge of Jupiter and its system. The retropropulsion module (RPM) as a major functional element of the Galileo spacecraft is described. The major mission and spacecraft requirements on the RPM are presented. Complexities of the integration process due to the international interface are identified. Challenges associated with integration with new launch vehicles, the Shuttle and upper stage, and their relationships to the RPM are discussed. The results of the integration process involving mission and propulsion performance, reliability, mechanical and thermal interfaces, and safety are described. Finally, considerations and recommendations for future missions involving international cooperation are given.

A perspective on modeling the multiscale response of energetic materials

NASA Astrophysics Data System (ADS)

Rice, Betsy M.

2017-01-01

The response of an energetic material to insult is perhaps one of the most difficult processes to model due to concurrent chemical and physical phenomena occurring over scales ranging from atomistic to continuum. Unraveling the interdependencies of these complex processes across the scales through modeling can only be done within a multiscale framework. In this paper, I will describe progress in the development of a predictive, experimentally validated multiscale reactive modeling capability for energetic materials at the Army Research Laboratory. I will also describe new challenges and research opportunities that have arisen in the course of our development which should be pursued in the future.

New Trends and Technological Challenges in the Industrial Production and Purification of Fructo-oligosaccharides.

PubMed

Nobre, Clarisse; Teixeira, José A; Rodrigues, Lígia R

2015-01-01

An increased commercial interest in fructo-oligosaccharides (FOS) has emerged in the last decade due to their prebiotic activity. At large scale, the FOS are produced by microbial enzymes from sucrose. A mixture of FOS and other saccharides is obtained in this process. The presence of such saccharides reduces the prebiotic, caloric, and cariogenic value of the final product. Therefore, many efforts have been conducted to obtain a product with increased FOS purity. This review comprises the most important technological and physicochemical aspects including FOS production and recovery processes; safety, dose and health claims concerning its intake; and commercially available FOS.

300 mm arrays and 30 nm Features: Frontiers in Sorting Biological Objects

NASA Astrophysics Data System (ADS)

Austin, Robert; Comella, Brandon; D'Silva, Joseph; Sturm, James

2014-03-01

One of the great challenges in prediction of metastasis is determining when the metastatic process actually begins. It is presumed that this process occurs due to passage of biological objects in the blood from tumor to remote sites. We will discuss our attempts to find both very large objects (circulating tumor cell clumps) and very small (exosomes) using a combination of extremely large scale photolithography on 300 mm wafers and deep-UV lithography to produce sub-100 nm arrays to sort exosomes. These technologies push the envelope of present day academic facilities . Supported by the National Science Foundation and the National Cancer Institute.

Development of Graphene Nanoplatelet-Reinforced AZ91 Magnesium Alloy by Solidification Processing

NASA Astrophysics Data System (ADS)

Kandemir, Sinan

2018-04-01

It is a challenging task to effectively incorporate graphene nanoplatelets (GNPs) which have recently emerged as potential reinforcement for strengthening metals into magnesium-based matrices by conventional solidification processes due to their large surface areas and poor wettability. A solidification processing which combines mechanical stirring and ultrasonic dispersion of reinforcements in liquid matrix was employed to develop AZ91 magnesium alloy matrix composites reinforced with 0.25 and 0.5 wt.% GNPs. The microstructural studies conducted with scanning and transmission electron microscopes revealed that fairly uniform distribution and dispersion of GNPs through the matrix were achieved due to effective combination of mechanical and ultrasonic stirring. The GNPs embedded into the magnesium matrix led to significant enhancement in the hardness, tensile strength and ductility of the composites compared to those of unreinforced AZ91 alloy. The strength enhancement was predominantly attributed to the grain refinement by the GNP addition and dislocation generation strengthening due to the coefficient of thermal expansion mismatch between the matrix and reinforcement. The improved ductility was attributed to the refinement of β eutectics by transforming from lamellar to the divorced eutectics due to the GNP additions. In addition, the strengthening efficiency of the composite with 0.25 wt.% GNP was found to be higher than those of the composite with 0.5 wt.% GNP as the agglomeration tendency of GNPs is increased with increasing GNP content. These results were compared with those of the GNP-reinforced magnesium composites reported in the literature, indicating the potential of the process introduced in this study in terms of fabricating light and high-performance metal matrix composites.

Giving parents a voice: A qualitative study of the challenges experienced by parents of children with disabilities.

PubMed

Resch, J Aaron; Mireles, Gerardo; Benz, Michael R; Grenwelge, Cheryl; Peterson, Rick; Zhang, Dalun

2010-05-01

This study sought to examine the specific sources of challenges as identified by parents of children with disabilities. Focus groups were conducted with 40 parent caregivers. Data gathered were coded into themes which were then analyzed through an intentional process of data reduction that resulted in the cross site validation of four superordinate themes. Four themes emerged as the most prominent barriers to positive parent wellbeing: (a) access to information and services, (b) financial barriers, (c) school and community inclusion, and (d) family support. These four themes are indicative of problems associated with a lack of match between caregiver needs and services, resources, or support available in the community to meet those needs. Caring for a child with a disability can be challenging, but many of these challenges are likely due to a lack of necessary environmental supports. Future research should expand on these findings and policy makers, scientists and providers should give particular attention to the environmental support needs of parents in order to create policies and interventions that are more family-centered.

Transcriptome of American oysters, Crassostrea virginica, in response to bacterial challenge: insights into potential mechanisms of disease resistance.

PubMed

McDowell, Ian C; Nikapitiya, Chamilani; Aguiar, Derek; Lane, Christopher E; Istrail, Sorin; Gomez-Chiarri, Marta

2014-01-01

The American oyster Crassostrea virginica, an ecologically and economically important estuarine organism, can suffer high mortalities in areas in the Northeast United States due to Roseovarius Oyster Disease (ROD), caused by the gram-negative bacterial pathogen Roseovarius crassostreae. The goals of this research were to provide insights into: 1) the responses of American oysters to R. crassostreae, and 2) potential mechanisms of resistance or susceptibility to ROD. The responses of oysters to bacterial challenge were characterized by exposing oysters from ROD-resistant and susceptible families to R. crassostreae, followed by high-throughput sequencing of cDNA samples from various timepoints after disease challenge. Sequence data was assembled into a reference transcriptome and analyzed through differential gene expression and functional enrichment to uncover genes and processes potentially involved in responses to ROD in the American oyster. While susceptible oysters experienced constant levels of mortality when challenged with R. crassostreae, resistant oysters showed levels of mortality similar to non-challenged oysters. Oysters exposed to R. crassostreae showed differential expression of transcripts involved in immune recognition, signaling, protease inhibition, detoxification, and apoptosis. Transcripts involved in metabolism were enriched in susceptible oysters, suggesting that bacterial infection places a large metabolic demand on these oysters. Transcripts differentially expressed in resistant oysters in response to infection included the immune modulators IL-17 and arginase, as well as several genes involved in extracellular matrix remodeling. The identification of potential genes and processes responsible for defense against R. crassostreae in the American oyster provides insights into potential mechanisms of disease resistance.

Transcriptome of American Oysters, Crassostrea virginica, in Response to Bacterial Challenge: Insights into Potential Mechanisms of Disease Resistance

PubMed Central

McDowell, Ian C.; Nikapitiya, Chamilani; Aguiar, Derek; Lane, Christopher E.; Istrail, Sorin; Gomez-Chiarri, Marta

2014-01-01

The American oyster Crassostrea virginica, an ecologically and economically important estuarine organism, can suffer high mortalities in areas in the Northeast United States due to Roseovarius Oyster Disease (ROD), caused by the gram-negative bacterial pathogen Roseovarius crassostreae. The goals of this research were to provide insights into: 1) the responses of American oysters to R. crassostreae, and 2) potential mechanisms of resistance or susceptibility to ROD. The responses of oysters to bacterial challenge were characterized by exposing oysters from ROD-resistant and susceptible families to R. crassostreae, followed by high-throughput sequencing of cDNA samples from various timepoints after disease challenge. Sequence data was assembled into a reference transcriptome and analyzed through differential gene expression and functional enrichment to uncover genes and processes potentially involved in responses to ROD in the American oyster. While susceptible oysters experienced constant levels of mortality when challenged with R. crassostreae, resistant oysters showed levels of mortality similar to non-challenged oysters. Oysters exposed to R. crassostreae showed differential expression of transcripts involved in immune recognition, signaling, protease inhibition, detoxification, and apoptosis. Transcripts involved in metabolism were enriched in susceptible oysters, suggesting that bacterial infection places a large metabolic demand on these oysters. Transcripts differentially expressed in resistant oysters in response to infection included the immune modulators IL-17 and arginase, as well as several genes involved in extracellular matrix remodeling. The identification of potential genes and processes responsible for defense against R. crassostreae in the American oyster provides insights into potential mechanisms of disease resistance. PMID:25122115

Secure distributed genome analysis for GWAS and sequence comparison computation.

PubMed

Zhang, Yihua; Blanton, Marina; Almashaqbeh, Ghada

2015-01-01

The rapid increase in the availability and volume of genomic data makes significant advances in biomedical research possible, but sharing of genomic data poses challenges due to the highly sensitive nature of such data. To address the challenges, a competition for secure distributed processing of genomic data was organized by the iDASH research center. In this work we propose techniques for securing computation with real-life genomic data for minor allele frequency and chi-squared statistics computation, as well as distance computation between two genomic sequences, as specified by the iDASH competition tasks. We put forward novel optimizations, including a generalization of a version of mergesort, which might be of independent interest. We provide implementation results of our techniques based on secret sharing that demonstrate practicality of the suggested protocols and also report on performance improvements due to our optimization techniques. This work describes our techniques, findings, and experimental results developed and obtained as part of iDASH 2015 research competition to secure real-life genomic computations and shows feasibility of securely computing with genomic data in practice.

Secure distributed genome analysis for GWAS and sequence comparison computation

PubMed Central

2015-01-01

Background The rapid increase in the availability and volume of genomic data makes significant advances in biomedical research possible, but sharing of genomic data poses challenges due to the highly sensitive nature of such data. To address the challenges, a competition for secure distributed processing of genomic data was organized by the iDASH research center. Methods In this work we propose techniques for securing computation with real-life genomic data for minor allele frequency and chi-squared statistics computation, as well as distance computation between two genomic sequences, as specified by the iDASH competition tasks. We put forward novel optimizations, including a generalization of a version of mergesort, which might be of independent interest. Results We provide implementation results of our techniques based on secret sharing that demonstrate practicality of the suggested protocols and also report on performance improvements due to our optimization techniques. Conclusions This work describes our techniques, findings, and experimental results developed and obtained as part of iDASH 2015 research competition to secure real-life genomic computations and shows feasibility of securely computing with genomic data in practice. PMID:26733307

Manufacturing DTaP-based combination vaccines: industrial challenges around essential public health tools.

PubMed

Vidor, Emmanuel; Soubeyrand, Benoit

2016-12-01

The manufacture of DTP-backboned combination vaccines is complex, and vaccine quality is evaluated by both batch composition and conformance of manufacturing history. Since their first availability, both the manufacturing regulations for DTP combination vaccines and their demand have evolved significantly. This has resulted in a constant need to modify manufacturing and quality control processes. Areas covered: Regulations that govern the manufacture of complex vaccines can be inconsistent between countries and need to be aligned with the regulatory requirements that apply in all countries of distribution. Changes in product mix and quantities can lead to uncertainty in vaccine supply maintenance. These problems are discussed in the context of the importance of these products as essential public health tools. Expert commentary: Increasing demand for complex vaccines globally has led to problems in supply due to intrinsically complex manufacturing and regulatory procedures. Vaccine manufacturers are fully engaged in the resolution of these challenges, but currently changes in demand need ideally to be anticipated approximately 3 years in advance due to long production cycle times.

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

Probing compressed mass spectra in electroweak supersymmetry with Recursive Jigsaw Reconstruction

NASA Astrophysics Data System (ADS)

Santoni, M.

2018-05-01

The lack of evidence for the production of colored supersymmetric particles at the LHC has increased interest in searches for superpartners of the electroweak SM gauge bosons, namely the neutralinos and charginos. These are challenging due to the weak nature of the production process, and the existing discovery reach has significant gaps in due to the difficulty of separating the supersymmetric signal from SM diboson events that produce similar final states and kinematics. We apply the Recursive Jigsaw Reconstruction technique to study final states enriched in charged leptons and missing transverse momentum, focusing on compressed topologies with direct production of charginos and neutralinos decaying to the lightest neutral supersymmetric particle through the emission of W and Z bosons. After presenting prototype analysis designs for future LHC runs, we demonstrate that its detectors have the potential to probe a significant amount of unexplored parameter space for chargino-neutralino associated production within the next few years, and show that the very challenging successful search for chargino pair production with compressed spectra might be possible by the end of the LHC lifetime.

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.

Leveraging human oversight and intervention in large-scale parallel processing of open-source data

NASA Astrophysics Data System (ADS)

Casini, Enrico; Suri, Niranjan; Bradshaw, Jeffrey M.

2015-05-01

The popularity of cloud computing along with the increased availability of cheap storage have led to the necessity of elaboration and transformation of large volumes of open-source data, all in parallel. One way to handle such extensive volumes of information properly is to take advantage of distributed computing frameworks like Map-Reduce. Unfortunately, an entirely automated approach that excludes human intervention is often unpredictable and error prone. Highly accurate data processing and decision-making can be achieved by supporting an automatic process through human collaboration, in a variety of environments such as warfare, cyber security and threat monitoring. Although this mutual participation seems easily exploitable, human-machine collaboration in the field of data analysis presents several challenges. First, due to the asynchronous nature of human intervention, it is necessary to verify that once a correction is made, all the necessary reprocessing is done in chain. Second, it is often needed to minimize the amount of reprocessing in order to optimize the usage of resources due to limited availability. In order to improve on these strict requirements, this paper introduces improvements to an innovative approach for human-machine collaboration in the processing of large amounts of open-source data in parallel.

Photocatalytic Anatase TiO2 Thin Films on Polymer Optical Fiber Using Atmospheric-Pressure Plasma.

PubMed

Baba, Kamal; Bulou, Simon; Choquet, Patrick; Boscher, Nicolas D

2017-04-19

Due to the undeniable industrial advantages of low-temperature atmospheric-pressure plasma processes, such as low cost, low temperature, easy implementation, and in-line process capabilities, they have become the most promising next-generation candidate system for replacing thermal chemical vapor deposition or wet chemical processes for the deposition of functional coatings. In the work detailed in this article, photocatalytic anatase TiO 2 thin films were deposited at a low temperature on polymer optical fibers using an atmospheric-pressure plasma process. This method overcomes the challenge of forming crystalline transition metal oxide coatings on polymer substrates by using a dry and up-scalable method. The careful selection of the plasma source and the titanium precursor, i.e., titanium ethoxide with a short alkoxy group, allowed the deposition of well-adherent, dense, and crystalline TiO 2 coatings at low substrate temperature. Raman and XRD investigations showed that the addition of oxygen to the precursor's carrier gas resulted in a further increase of the film's crystallinity. Furthermore, the films deposited in the presence of oxygen exhibited a better photocatalytic activity toward methylene blue degradation assumedly due to their higher amount of photoactive {101} facets.

High-throughput electrical characterization for robust overlay lithography control

NASA Astrophysics Data System (ADS)

Devender, Devender; Shen, Xumin; Duggan, Mark; Singh, Sunil; Rullan, Jonathan; Choo, Jae; Mehta, Sohan; Tang, Teck Jung; Reidy, Sean; Holt, Jonathan; Kim, Hyung Woo; Fox, Robert; Sohn, D. K.

2017-03-01

Realizing sensitive, high throughput and robust overlay measurement is a challenge in current 14nm and advanced upcoming nodes with transition to 300mm and upcoming 450mm semiconductor manufacturing, where slight deviation in overlay has significant impact on reliability and yield1). Exponentially increasing number of critical masks in multi-patterning lithoetch, litho-etch (LELE) and subsequent LELELE semiconductor processes require even tighter overlay specification2). Here, we discuss limitations of current image- and diffraction- based overlay measurement techniques to meet these stringent processing requirements due to sensitivity, throughput and low contrast3). We demonstrate a new electrical measurement based technique where resistance is measured for a macro with intentional misalignment between two layers. Overlay is quantified by a parabolic fitting model to resistance where minima and inflection points are extracted to characterize overlay control and process window, respectively. Analyses using transmission electron microscopy show good correlation between actual overlay performance and overlay obtained from fitting. Additionally, excellent correlation of overlay from electrical measurements to existing image- and diffraction- based techniques is found. We also discuss challenges of integrating electrical measurement based approach in semiconductor manufacturing from Back End of Line (BEOL) perspective. Our findings open up a new pathway for accessing simultaneous overlay as well as process window and margins from a robust, high throughput and electrical measurement approach.

Direct compression of chitosan: process and formulation factors to improve powder flow and tablet performance.

PubMed

Buys, Gerhard M; du Plessis, Lissinda H; Marais, Andries F; Kotze, Awie F; Hamman, Josias H

2013-06-01

Chitosan is a polymer derived from chitin that is widely available at relatively low cost, but due to compression challenges it has limited application for the production of direct compression tablets. The aim of this study was to use certain process and formulation variables to improve manufacturing of tablets containing chitosan as bulking agent. Chitosan particle size and flow properties were determined, which included bulk density, tapped density, compressibility and moisture uptake. The effect of process variables (i.e. compression force, punch depth, percentage compaction in a novel double fill compression process) and formulation variables (i.e. type of glidant, citric acid, pectin, coating with Eudragit S®) on chitosan tablet performance (i.e. mass variation, tensile strength, dissolution) was investigated. Moisture content of the chitosan powder, particle size and the inclusion of glidants had a pronounced effect on its flow ability. Varying the percentage compaction during the first cycle of a double fill compression process produced chitosan tablets with more acceptable tensile strength and dissolution rate properties. The inclusion of citric acid and pectin into the formulation significantly decreased the dissolution rate of isoniazid from the tablets due to gel formation. Direct compression of chitosan powder into tablets can be significantly improved by the investigated process and formulation variables as well as applying a double fill compression process.

Challenges and opportunities for heavy scalar searches in the tt¯ channel at the LHC

DOE PAGES

Carena, Marcela; Liu, Zhen

2016-11-25

Heavy scalar and pseudoscalar resonance searches through themore » $$gg\\rightarrow S\\rightarrow t\\bar t$$ process are challenging due to the peculiar behavior of the large interference effects with the standard model $$t\\bar t$$ background. Such effects generate non-trivial lineshapes from additional relative phases between the signal and background amplitudes. We provide the analytic expressions for the differential cross sections to understand the interference effects in the heavy scalar signal lineshapes. We extend our study to the case of CP-violation and further consider the effect of bottom quarks in the production and decay processes. We also evaluate the contributions from additional particles to the gluon fusion production process, such as stops and vector-like quarks, that could lead to significant changes in the behavior of the signal lineshapes. Taking into account the large interference effects, we perform lineshape searches at the LHC and discuss the importance of the systematic uncertainties and smearing effects. Lastly, we present projected sensitivities for two LHC performance scenarios to probe the $$gg\\rightarrow S \\rightarrow t\\bar t$$ channel in various models.« less

Radiation processing techniques in remediation of pollutants, and the role of the IAEA in supporting capacity building in developing countries

NASA Astrophysics Data System (ADS)

Haji-Saeid, S. Mohammad.; Sampa, M. H.; Safrany, A.; Sabharwal, S.; Ramamoorthy, N.

2012-08-01

Radiation treatment, or a combination of radiation with conventional biological-chemical-physical processes, can help in the remediation of contaminated surfaces and in combating industrial chemical effluents and air pollution. The use of ionizing radiation as a powerful tool for inactivation of microbes is a valuable option to address likely threats from biohazard contamination that could be introduced either deliberately or inadvertently into areas where the public are exposed to, as well as for treatment of volatile organic compounds and similar hazardous chemical agents is an emerging development in tackling harmful pollutants. The role of the IAEA has been crucial both in supporting the development of local capabilities as well as in fostering international cooperation due to the multidisciplinary expertise required for achieving sustainable benefits. The IAEA is implementing Coordinated Research Projects, (CRP) thematic topical reviews of issues and challenges involved, and Technical Cooperation (TC) assistance in establishing and maintaining infrastructure in the MS. This paper will give an insight into the above mentioned IAEA activities, with examples of successes achieved through CRPs, as well as challenges on the road for broader dissemination of radiation processing technology for environmental remediation.

Engineered decellularized matrices to instruct bone regeneration processes.

PubMed

Papadimitropoulos, Adam; Scotti, Celeste; Bourgine, Paul; Scherberich, Arnaud; Martin, Ivan

2015-01-01

Despite the significant progress in the field of bone tissue engineering, cell-based products have not yet reached the stage of clinical adoption. This is due to the uncertain advantages from the standard-of-care, combined with challenging cost-and regulatory-related issues. Novel therapeutic approaches could be based on exploitation of the intrinsic regenerative capacity of bone tissue, provided the development of a deeper understanding of its healing mechanisms. While it is well-established that endogenous progenitors can be activated toward bone formation by overdoses of single morphogens, the challenge to stimulate the healing processes by coordinated and controlled stimulation of specific cell populations remains open. Here, we review the recent approaches to generate osteoinductive materials based on the use of decellularized extracellular matrices (ECM) as reservoirs of multiple factors presented at physiological doses and through the appropriate ligands. We then propose the generation of customized engineered and decellularized ECM (i) as a tool to better understand the processes of bone regeneration and (ii) as safe and effective "off-the-shelf" bone grafts for clinical use. This article is part of a Special Issue entitled Stem Cells and Bone. Copyright © 2014 Elsevier Inc. All rights reserved.

Efficient Exploration of Membrane-Associated Phenomena at Atomic Resolution.

PubMed

Vermaas, Josh V; Baylon, Javier L; Arcario, Mark J; Muller, Melanie P; Wu, Zhe; Pogorelov, Taras V; Tajkhorshid, Emad

2015-06-01

Biological membranes constitute a critical component in all living cells. In addition to providing a conducive environment to a wide range of cellular processes, including transport and signaling, mounting evidence has established active participation of specific lipids in modulating membrane protein function through various mechanisms. Understanding lipid-protein interactions underlying these mechanisms at a sufficiently high resolution has proven extremely challenging, partly due to the semi-fluid nature of the membrane. In order to address this challenge computationally, multiple methods have been developed, including an alternative membrane representation termed highly mobile membrane mimetic (HMMM) in which lateral lipid diffusion has been significantly enhanced without compromising atomic details. The model allows for efficient sampling of lipid-protein interactions at atomic resolution, thereby significantly enhancing the effectiveness of molecular dynamics simulations in capturing membrane-associated phenomena. In this review, after providing an overview of HMMM model development, we will describe briefly successful application of the model to study a variety of membrane processes, including lipid-dependent binding and insertion of peripheral proteins, the mechanism of phospholipid insertion into lipid bilayers, and characterization of optimal tilt angle of transmembrane helices. We conclude with practical recommendations for proper usage of the model in simulation studies of membrane processes.

Multiphysical FE-analysis of a front-end bending phenomenon in a hot strip mill

NASA Astrophysics Data System (ADS)

Ilmola, Joonas; Seppälä, Oskari; Leinonen, Olli; Pohjonen, Aarne; Larkiola, Jari; Jokisaari, Juha; Putaansuu, Eero

2018-05-01

In hot steel rolling processes, a slab is generally rolled to a transfer bar in a roughing process and to a strip in a hot strip rolling process. Over several rolling passes the front-end may bend upward or downward due to asymmetrical rolling conditions causing entry problems in the next rolling pass. Many different factors may affect the front-end bending phenomenon and are very challenging to measure. Thus, a customized finite element model is designed and built to simulate the front-end bending phenomenon in a hot strip rolling process. To simulate the functioning of the hot strip mill precisely, automated controlling logic of the mill must be considered. In this paper we studied the effect of roll bite friction conditions and amount of reduction on the front-end bending phenomenon in a hot strip rolling process.

Automating multistep flow synthesis: approach and challenges in integrating chemistry, machines and logic

PubMed Central

Shukla, Chinmay A

2017-01-01

The implementation of automation in the multistep flow synthesis is essential for transforming laboratory-scale chemistry into a reliable industrial process. In this review, we briefly introduce the role of automation based on its application in synthesis viz. auto sampling and inline monitoring, optimization and process control. Subsequently, we have critically reviewed a few multistep flow synthesis and suggested a possible control strategy to be implemented so that it helps to reliably transfer the laboratory-scale synthesis strategy to a pilot scale at its optimum conditions. Due to the vast literature in multistep synthesis, we have classified the literature and have identified the case studies based on few criteria viz. type of reaction, heating methods, processes involving in-line separation units, telescopic synthesis, processes involving in-line quenching and process with the smallest time scale of operation. This classification will cover the broader range in the multistep synthesis literature. PMID:28684977

Thermal sensors to control polymer forming. Challenge and solutions

NASA Astrophysics Data System (ADS)

Lemeunier, F.; Boyard, N.; Sarda, A.; Plot, C.; Lefèvre, N.; Petit, I.; Colomines, G.; Allanic, N.; Bailleul, J. L.

2017-10-01

Many thermal sensors are already used, for many years, to better understand and control material forming processes, especially polymer processing. Due to technical constraints (high pressure, sealing, sensor dimensions…) the thermal measurement is often performed in the tool or close its surface. Thus, it only gives partial and disturbed information. Having reliable information about the heat flux exchanges between the tool and the material during the process would be very helpful to improve the control of the process and to favor the development of new materials. In this work, we present several sensors developed in labs to study the molding steps in forming processes. The analysis of the obtained thermal measurements (temperature, heat flux) shows the required sensitivity threshold of sensitivity of thermal sensors to be able to detect on-line the rate of thermal reaction. Based on these data, we will present new sensor designs which have been patented.

Efficient LIDAR Point Cloud Data Managing and Processing in a Hadoop-Based Distributed Framework

NASA Astrophysics Data System (ADS)

Wang, C.; Hu, F.; Sha, D.; Han, X.

2017-10-01

Light Detection and Ranging (LiDAR) is one of the most promising technologies in surveying and mapping city management, forestry, object recognition, computer vision engineer and others. However, it is challenging to efficiently storage, query and analyze the high-resolution 3D LiDAR data due to its volume and complexity. In order to improve the productivity of Lidar data processing, this study proposes a Hadoop-based framework to efficiently manage and process LiDAR data in a distributed and parallel manner, which takes advantage of Hadoop's storage and computing ability. At the same time, the Point Cloud Library (PCL), an open-source project for 2D/3D image and point cloud processing, is integrated with HDFS and MapReduce to conduct the Lidar data analysis algorithms provided by PCL in a parallel fashion. The experiment results show that the proposed framework can efficiently manage and process big LiDAR data.

[Postdonation information: the French fourth hemovigilance sub-process].

PubMed

Py, J-Y; Sandid, I; Jbilou, S; Dupuis, M; Adda, R; Narbey, D; Djoudi, R

2014-11-01

Postdonation information is the knowledge of information about the donor or his donation, occurring after it, which challenges quality or safety of the blood products stemming from this or other donations. Classical hemovigilance sub-processes concerning donors or recipients adverse events do not cover this topic. France is just about to make it official as a fourth sub-process. Less formal management of postdonation information is already set up for more than ten years. French data of the year 2013 are presented, including the regional notification level and the national reporting one. A significant level of heterogeneity is observed as for other hemovigilance sub-processes. It is mainly due to subjective rather than objective differences in risk appreciation. A real consensual work is expected about it in the future. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Culturally Competent Informed-Consent Process to Evaluate a Social Policy for Older Persons With Low Literacy: The Mexican Case

PubMed Central

Aguila, Emma; Weidmer, Beverly A.; Illingworth, Alfonso Rivera; Martinez, Homero

2017-01-01

The informed-consent process seeks to provide complete information to participants about a research project and to protect personal information they may disclose. In this article, we present an informed-consent process that we piloted and improved to obtain consent from older adults in Yucatan, Mexico. Respondents had limited fluency in Spanish, spoke the local Mayan language, and had some physical limitations due to their age. We describe how we adapted the informed-consent process to comply with U.S. and Mexican regulations, while simplifying the forms and providing them in Spanish and Mayan. We present the challenges and lessons learned when dealing with low-literacy older populations, some with diminished autonomy, in a bilingual context and a binational approach to the legal framework. PMID:28824826

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.

Modified SPC for short run test and measurement process in multi-stations

NASA Astrophysics Data System (ADS)

Koh, C. K.; Chin, J. F.; Kamaruddin, S.

2018-03-01

Due to short production runs and measurement error inherent in electronic test and measurement (T&M) processes, continuous quality monitoring through real-time statistical process control (SPC) is challenging. Industry practice allows the installation of guard band using measurement uncertainty to reduce the width of acceptance limit, as an indirect way to compensate the measurement errors. This paper presents a new SPC model combining modified guard band and control charts (\\bar{\\text{Z}} chart and W chart) for short runs in T&M process in multi-stations. The proposed model standardizes the observed value with measurement target (T) and rationed measurement uncertainty (U). S-factor (S f) is introduced to the control limits to improve the sensitivity in detecting small shifts. The model was embedded in automated quality control system and verified with a case study in real industry.

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

LaRue, Jerry; Krejci, Ondrej; Yu, Liang

Here, the direct elucidation of the reaction pathways in heterogeneous catalysis has been challenging due the short-lived nature of reaction intermediates. Here, we directly measured on ultrafast timescales the initial hydrogenation steps of adsorbed CO on a Ru catalyst surface, which is known as the bottleneck reaction in syngas and CO 2 reforming processes. We initiated the hydrogenation of CO with an ultrafast laser temperature jump and probed transient changes in the electronic structure using real-time x-ray spectroscopy. In combination with theoretical simulations, we verified the formation of CHO during CO hydrogenation.

Par-baked Bread Technology: Formulation and Process Studies to Improve Quality.

PubMed

Almeida, Eveline Lopes; Steel, Caroline Joy; Chang, Yoon Kil

2016-01-01

Extending the shelf-life of bakery products has been an important requirement resulting from the mechanization of this industry and the need to increase the distance for the distribution of final products, caused by the increase in production and consumer demand. Technologies based on the interruption of the breadmaking process represent an alternative to overcome product staling and microbiological deterioration. The production of par-baked breads is one of these technologies. It consists of baking the bread in two stages, and due to the possibility of retarding the second stage, it can be said that the bread can always be offered fresh to the consumer. The technology inserts logistics as part of the production process and creates the "hot point" concept, these being the locations where the bread is finalized, such as in the consumers' homes or sales locations. In this work, a review of the papers published on this subject was carried out, and aspects related to both the formulation and the process were considered. This technology still faces a few challenges, such as solving bread quality problems that appear due to process modifications, and these will also be considered. The market for these breads has grown rapidly and the bakery industry searches innovations related to par-baked bread technology.

Selective laser melting of Inconel super alloy-a review

NASA Astrophysics Data System (ADS)

Karia, M. C.; Popat, M. A.; Sangani, K. B.

2017-07-01

Additive manufacturing is a relatively young technology that uses the principle of layer by layer addition of material in solid, liquid or powder form to develop a component or product. The quality of additive manufactured part is one of the challenges to be addressed. Researchers are continuously working at various levels of additive manufacturing technologies. One of the significant powder bed processes for met als is Selective Laser Melting (SLM). Laser based processes are finding more attention of researchers and industrial world. The potential of this technique is yet to be fully explored. Due to very high strength and creep resistance Inconel is extensively used nickel based super alloy for manufacturing components for aerospace, automobile and nuclear industries. Due to law content of Aluminum and Titanium, it exhibits good fabricability too. Therefore the alloy is ideally suitable for selective laser melting to manufacture intricate components with high strength requirements. The selection of suitable process for manufacturing for a specific component depends on geometrical complexity, production quantity, and cost and required strength. There are numerous researchers working on various aspects like metallurgical and micro structural investigations and mechanical properties, geometrical accuracy, effects of process parameters and its optimization and mathematical modeling etc. The present paper represents a comprehensive overview of selective laser melting process for Inconel group of alloys.

Ultrasonic grinding of optical materials

NASA Astrophysics Data System (ADS)

Cahill, Michael; Bechtold, Michael; Fess, Edward; Stephan, Thomas; Bechtold, Rob

2017-10-01

Hard ceramic optical materials such as sapphire, ALON, Spinel, PCA, or Silicon Carbide can present a significant challenge in manufacturing precision optical components due to their tough mechanical properties. These are also the same mechanical properties that make them desirable materials when used in harsh environments. Slow processing speeds, premature tool wear, and poor surface quality are common results of the tough mechanical properties of these materials. Often, as a preparatory stage for polishing, the finish of the ground surface greatly influences the polishing process and the resulting finished product. To overcome these challenges, OptiPro Systems has developed an ultrasonic assisted grinding technology, OptiSonic, which has been designed for the precision optics and ceramics industry. OptiSonic utilizes a custom tool holder designed to produce oscillations, in microns of amplitude, in line with the rotating spindle. A software package, IntelliSonic, is integral to the function of this platform. IntelliSonic can automatically characterize tooling during setup to identify and select the ideal resonant peak which to operate at. Then, while grinding, IntelliSonic continuously adjusts the output frequency for optimal grinding efficiency while in contact with the part. This helps maintain a highly consistent process under changing load conditions for a more precise surface. Utilizing a variety of instruments, tests have proven to show a reduction in force between tool and part by up to 50%, while increasing the surface quality and reducing tool wear. This paper will present the challenges associated with these materials and solutions created to overcome them.

Preprocessing Structured Clinical Data for Predictive Modeling and Decision Support

PubMed Central

Oliveira, Mónica Duarte; Janela, Filipe; Martins, Henrique M. G.

2016-01-01

Summary Background EHR systems have high potential to improve healthcare delivery and management. Although structured EHR data generates information in machine-readable formats, their use for decision support still poses technical challenges for researchers due to the need to preprocess and convert data into a matrix format. During our research, we observed that clinical informatics literature does not provide guidance for researchers on how to build this matrix while avoiding potential pitfalls. Objectives This article aims to provide researchers a roadmap of the main technical challenges of preprocessing structured EHR data and possible strategies to overcome them. Methods Along standard data processing stages – extracting database entries, defining features, processing data, assessing feature values and integrating data elements, within an EDPAI framework –, we identified the main challenges faced by researchers and reflect on how to address those challenges based on lessons learned from our research experience and on best practices from related literature. We highlight the main potential sources of error, present strategies to approach those challenges and discuss implications of these strategies. Results Following the EDPAI framework, researchers face five key challenges: (1) gathering and integrating data, (2) identifying and handling different feature types, (3) combining features to handle redundancy and granularity, (4) addressing data missingness, and (5) handling multiple feature values. Strategies to address these challenges include: cross-checking identifiers for robust data retrieval and integration; applying clinical knowledge in identifying feature types, in addressing redundancy and granularity, and in accommodating multiple feature values; and investigating missing patterns adequately. Conclusions This article contributes to literature by providing a roadmap to inform structured EHR data preprocessing. It may advise researchers on potential pitfalls and implications of methodological decisions in handling structured data, so as to avoid biases and help realize the benefits of the secondary use of EHR data. PMID:27924347

Genome-Wide Association Studies of Drug-Resistance Determinants.

PubMed

Volkman, Sarah K; Herman, Jonathan; Lukens, Amanda K; Hartl, Daniel L

2017-03-01

Population genetic strategies that leverage association, selection, and linkage have identified drug-resistant loci. However, challenges and limitations persist in identifying drug-resistance loci in malaria. In this review we discuss the genetic basis of drug resistance and the use of genome-wide association studies, complemented by selection and linkage studies, to identify and understand mechanisms of drug resistance and response. We also discuss the implications of nongenetic mechanisms of drug resistance recently reported in the literature, and present models of the interplay between nongenetic and genetic processes that contribute to the emergence of drug resistance. Throughout, we examine artemisinin resistance as an example to emphasize challenges in identifying phenotypes suitable for population genetic studies as well as complications due to multiple-factor drug resistance. Copyright © 2016. Published by Elsevier Ltd.

Challenges in the analysis of complex systems: introduction and overview

NASA Astrophysics Data System (ADS)

Hastings, Harold M.; Davidsen, Jörn; Leung, Henry

2017-12-01

One of the main challenges of modern physics is to provide a systematic understanding of systems far from equilibrium exhibiting emergent behavior. Prominent examples of such complex systems include, but are not limited to the cardiac electrical system, the brain, the power grid, social systems, material failure and earthquakes, and the climate system. Due to the technological advances over the last decade, the amount of observations and data available to characterize complex systems and their dynamics, as well as the capability to process that data, has increased substantially. The present issue discusses a cross section of the current research on complex systems, with a focus on novel experimental and data-driven approaches to complex systems that provide the necessary platform to model the behavior of such systems.

Development of a public health reporting data warehouse: lessons learned.

PubMed

Rizi, Seyed Ali Mussavi; Roudsari, Abdul

2013-01-01

Data warehouse projects are perceived to be risky and prone to failure due to many organizational and technical challenges. However, often iterative and lengthy processes of implementation of data warehouses at an enterprise level provide an opportunity for formative evaluation of these solutions. This paper describes lessons learned from successful development and implementation of the first phase of an enterprise data warehouse to support public health surveillance at British Columbia Centre for Disease Control. Iterative and prototyping approach to development, overcoming technical challenges of extraction and integration of data from large scale clinical and ancillary systems, a novel approach to record linkage, flexible and reusable modeling of clinical data, and securing senior management support at the right time were the main factors that contributed to the success of the data warehousing project.

Monitoring biological diversity: strategies, tools, limitations, and challenges

USGS Publications Warehouse

Beever, E.A.

2006-01-01

Monitoring is an assessment of the spatial and temporal variability in one or more ecosystem properties, and is an essential component of adaptive management. Monitoring can help determine whether mandated environmental standards are being met and can provide an early-warning system of ecological change. Development of a strategy for monitoring biological diversity will likely be most successful when based upon clearly articulated goals and objectives and may be enhanced by including several key steps in the process. Ideally, monitoring of biological diversity will measure not only composition, but also structure and function at the spatial and temporal scales of interest. Although biodiversity monitoring has several key limitations as well as numerous theoretical and practical challenges, many tools and strategies are available to address or overcome such challenges; I summarize several of these. Due to the diversity of spatio-temporal scales and comprehensiveness encompassed by existing definitions of biological diversity, an effective monitoring design will reflect the desired sampling domain of interest and its key stressors, available funding, legal requirements, and organizational goals.

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.

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.

Industrial Development and Challenges of Water Pollution in Coastal Areas: The Case of Surat, India

NASA Astrophysics Data System (ADS)

Bansal, Neeru

2018-03-01

Industrialisation plays an important role in the economic development of a country, however, pollution is the inevitable price paid for this development. Surat, a major industrial hub in western India, is located on the bank of the river Tapi and extends up to the Arabian Sea. The city is characterised by the presence of a number of creeks (known as ‘khadis’ in local language). This paper focusses on the industrial development in Surat and the challenges faced by the city due to water pollution. A constant deterioration in the quality of surface water resources has been observed due to discharge of treated or partially treated effluents from the industries. The problem of water pollution becomes critical due to increase in frequency of flooding, risks faced by the city due to climate change and the ineffective environmental governance. The paper provides insights into the challenges faced by the city and the learnings can lead to adoption of policy initiatives and other measures which can effectively address these challenges.

Recent Advances of Rare-Earth Ion Doped Luminescent Nanomaterials in Perovskite Solar Cells

PubMed Central

Qiao, Yu; Li, Shuhan; Liu, Wenhui; Ran, Meiqing; Lu, Haifei

2018-01-01

Organic-inorganic lead halide based perovskite solar cells have received broad interest due to their merits of low fabrication cost, a low temperature solution process, and high energy conversion efficiencies. Rare-earth (RE) ion doped nanomaterials can be used in perovskite solar cells to expand the range of absorption spectra and improve the stability due to its upconversion and downconversion effect. This article reviews recent progress in using RE-ion-doped nanomaterials in mesoporous electrodes, perovskite active layers, and as an external function layer of perovskite solar cells. Finally, we discuss the challenges facing the effective use of RE-ion-doped nanomaterials in perovskite solar cells and present some prospects for future research. PMID:29342950

Multimodality Imaging Approach towards Primary Aortic Sarcomas Arising after Endovascular Abdominal Aortic Aneurysm Repair: Case Series Report.

PubMed

Kamran, Mudassar; Fowler, Kathryn J; Mellnick, Vincent M; Sicard, Gregorio A; Narra, Vamsi R

2016-06-01

Primary aortic neoplasms are rare. Aortic sarcoma arising after endovascular aneurysm repair (EVAR) is a scarce subset of primary aortic malignancies, reports of which are infrequent in the published literature. The diagnosis of aortic sarcoma is challenging due to its non-specific clinical presentation, and the prognosis is poor due to delayed diagnosis, rapid proliferation, and propensity for metastasis. Post-EVAR, aortic sarcomas may mimic other more common aortic processes on surveillance imaging. Radiologists are rarely knowledgeable about this rare entity for which multimodality imaging and awareness are invaluable in early diagnosis. A series of three pathologically confirmed cases are presented to display the multimodality imaging features and clinical presentations of aortic sarcoma arising after EVAR.

Preface: Special Topic on Nucleation: New Concepts and Discoveries.

PubMed

Kelton, K F; Frenkel, Daan

2016-12-07

Many phenomena in the world around us depend on infrequent, yet short-lived, events that completely alter how a system subsequently develops in time. In the physical sciences, there are many examples of such crucial "rare events." Among the most important of these are nucleation processes, in which, due to a rare fluctuation, a new phase forms spontaneously within a meta-stable parent phase. Because nucleation processes are both rare and rapid and happen on a microscopic spatial scale, their experimental study is challenging. In recent years, there have been major developments both in the experimental study of nucleation phenomena and in the numerical simulation of such processes. As the articles in this special issue demonstrate, these recent advances in the ability to probe nucleation phenomena have transformed our understanding of the field.

3D interconnect metrology in CMS/ITRI

NASA Astrophysics Data System (ADS)

Ku, Y. S.; Shyu, D. M.; Hsu, W. T.; Chang, P. Y.; Chen, Y. C.; Pang, H. L.

2011-05-01

Semiconductor device packaging technology is rapidly advancing, in response to the demand for thinner and smaller electronic devices. Three-dimensional chip/wafer stacking that uses through-silicon vias (TSV) is a key technical focus area, and the continuous development of this novel technology has created a need for non-contact characterization. Many of these challenges are novel to the industry due to the relatively large variety of via sizes and density, and new processes such as wafer thinning and stacked wafer bonding. This paper summarizes the developing metrology that has been used during via-middle & via-last TSV process development at EOL/ITRI. While there is a variety of metrology and inspection applications for 3D interconnect processing, the main topics covered here are via CD/depth measurement, thinned wafer inspection and wafer warpage measurement.

The Dawn of Lead-Free Perovskite Solar Cell: Highly Stable Double Perovskite Cs2AgBiBr6 Film.

PubMed

Wu, Cuncun; Zhang, Qiaohui; Liu, Yang; Luo, Wei; Guo, Xuan; Huang, Ziru; Ting, Hungkit; Sun, Weihai; Zhong, Xinrui; Wei, Shiyuan; Wang, Shufeng; Chen, Zhijian; Xiao, Lixin

2018-03-01

Recently, lead-free double perovskites have emerged as a promising environmentally friendly photovoltaic material for their intrinsic thermodynamic stability, appropriate bandgaps, small carrier effective masses, and low exciton binding energies. However, currently no solar cell based on these double perovskites has been reported, due to the challenge in film processing. Herein, a first lead-free double perovskite planar heterojunction solar cell with a high quality Cs 2 AgBiBr 6 film, fabricated by low-pressure assisted solution processing under ambient conditions, is reported. The device presents a best power conversion efficiency of 1.44%. The preliminary efficiency and the high stability under ambient condition without encapsulation, together with the high film quality with simple processing, demonstrate promise for lead-free perovskite solar cells.

a Hadoop-Based Distributed Framework for Efficient Managing and Processing Big Remote Sensing Images

NASA Astrophysics Data System (ADS)

Wang, C.; Hu, F.; Hu, X.; Zhao, S.; Wen, W.; Yang, C.

2015-07-01

Various sensors from airborne and satellite platforms are producing large volumes of remote sensing images for mapping, environmental monitoring, disaster management, military intelligence, and others. However, it is challenging to efficiently storage, query and process such big data due to the data- and computing- intensive issues. In this paper, a Hadoop-based framework is proposed to manage and process the big remote sensing data in a distributed and parallel manner. Especially, remote sensing data can be directly fetched from other data platforms into the Hadoop Distributed File System (HDFS). The Orfeo toolbox, a ready-to-use tool for large image processing, is integrated into MapReduce to provide affluent image processing operations. With the integration of HDFS, Orfeo toolbox and MapReduce, these remote sensing images can be directly processed in parallel in a scalable computing environment. The experiment results show that the proposed framework can efficiently manage and process such big remote sensing data.

Uncharted territories of the patent-restoration due-diligence challenge.

PubMed

Gaudry, Kate S

2011-01-01

The innovation and development incentives offered by the patent system are mitigated if a substantial portion of the patent term is lost while obtaining product approval through the Food and Drug Administration (FDA). The Drug Price Competition and Patent Restoration Act was enacted to return some of the lost patent term to the patentee. However, any person can petition the FDA, contending that the patentee did not act with due diligence in seeking FDA approval of the product during the regulatory review period. A successful challenge will reduce the restored term, such that the patentee is not compensated for time lost due to his own non-diligent actions. While the current due-diligence regulations provide a vague and flexible standard, earlier drafts of the regulations and FDA responses to comments provide insight as to the types of factors the FDA is likely to consider when assessing an applicant's diligence. A due-diligence petition has only been filed three times, and in none of these cases did the FDA issue a decision based on substantive diligence matters. Still, detailed examination of these petitions is also instructive in predicting the success of due-diligence challenges. Statute-imposed maximums and applicants' own incentives to act diligently may minimize the utility of the due-diligence challenges in some contexts. However, in other contexts, I propose that these petitions offer a feasible approach towards limiting pharmaceutical monopolies.

Dynamic-template-directed multiscale assembly for large-area coating of highly-aligned conjugated polymer thin films

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

Mohammadi, Erfan; Zhao, Chuankai; Meng, Yifei

Solution processable semiconducting polymers have been under intense investigations due to their diverse applications from printed electronics to biomedical devices. However, controlling the macromolecular assembly across length scales during solution coating remains a key challenge, largely due to the disparity in timescales of polymer assembly and high-throughput printing/coating. Herein we propose the concept of dynamic templating to expedite polymer nucleation and the ensuing assembly process, inspired by biomineralization templates capable of surface reconfiguration. Molecular dynamic simulations reveal that surface reconfigurability is key to promoting template–polymer interactions, thereby lowering polymer nucleation barrier. Employing ionic-liquid-based dynamic template during meniscus-guided coating results inmore » highly aligned, highly crystalline donor-acceptor polymer thin films over large area (41cm 2) and promoted charge transport along both the polymer backbone and the π-π stacking direction in field-effect transistors. We further demonstrate that the charge transport anisotropy can be reversed by tuning the degree of polymer backbone alignment.« less

Dynamic-template-directed multiscale assembly for large-area coating of highly-aligned conjugated polymer thin films

PubMed Central

Mohammadi, Erfan; Zhao, Chuankai; Meng, Yifei; Qu, Ge; Zhang, Fengjiao; Zhao, Xikang; Mei, Jianguo; Zuo, Jian-Min; Shukla, Diwakar; Diao, Ying

2017-01-01

Solution processable semiconducting polymers have been under intense investigations due to their diverse applications from printed electronics to biomedical devices. However, controlling the macromolecular assembly across length scales during solution coating remains a key challenge, largely due to the disparity in timescales of polymer assembly and high-throughput printing/coating. Herein we propose the concept of dynamic templating to expedite polymer nucleation and the ensuing assembly process, inspired by biomineralization templates capable of surface reconfiguration. Molecular dynamic simulations reveal that surface reconfigurability is key to promoting template–polymer interactions, thereby lowering polymer nucleation barrier. Employing ionic-liquid-based dynamic template during meniscus-guided coating results in highly aligned, highly crystalline donor–acceptor polymer thin films over large area (>1 cm2) and promoted charge transport along both the polymer backbone and the π–π stacking direction in field-effect transistors. We further demonstrate that the charge transport anisotropy can be reversed by tuning the degree of polymer backbone alignment. PMID:28703136

Active temporal multiplexing of indistinguishable heralded single photons

PubMed Central

Xiong, C.; Zhang, X.; Liu, Z.; Collins, M. J.; Mahendra, A.; Helt, L. G.; Steel, M. J.; Choi, D. -Y.; Chae, C. J.; Leong, P. H. W.; Eggleton, B. J.

2016-01-01

It is a fundamental challenge in quantum optics to deterministically generate indistinguishable single photons through non-deterministic nonlinear optical processes, due to the intrinsic coupling of single- and multi-photon-generation probabilities in these processes. Actively multiplexing photons generated in many temporal modes can decouple these probabilities, but key issues are to minimize resource requirements to allow scalability, and to ensure indistinguishability of the generated photons. Here we demonstrate the multiplexing of photons from four temporal modes solely using fibre-integrated optics and off-the-shelf electronic components. We show a 100% enhancement to the single-photon output probability without introducing additional multi-photon noise. Photon indistinguishability is confirmed by a fourfold Hong–Ou–Mandel quantum interference with a 91±16% visibility after subtracting multi-photon noise due to high pump power. Our demonstration paves the way for scalable multiplexing of many non-deterministic photon sources to a single near-deterministic source, which will be of benefit to future quantum photonic technologies. PMID:26996317

A review on sludge dewatering indices.

PubMed

To, Vu Hien Phuong; Nguyen, Tien Vinh; Vigneswaran, Saravanamuth; Ngo, Huu Hao

2016-01-01

Dewatering of sludge from sewage treatment plants is proving to be a significant challenge due to the large amounts of residual sludges generated annually. In recent years, research and development have focused on improving the dewatering process in order to reduce subsequent costs of sludge management and transport. To achieve this goal, it is necessary to establish reliable indices that reflect the efficiency of sludge dewatering. However, the evaluation of sludge dewaterability is not an easy task due to the highly complex nature of sewage sludge and variations in solid-liquid separation methods. Most traditional dewatering indices fail to predict the maximum cake solids content achievable during full-scale dewatering. This paper reviews the difficulties in assessing sludge dewatering performance, and the main techniques used to evaluate dewatering performance are compared and discussed in detail. Finally, the paper suggests a new dewatering index, namely the modified centrifugal index, which is demonstrated to be an appropriate indicator for estimating the final cake solids content as well as simulating the prototype dewatering process.

Dynamic-template-directed multiscale assembly for large-area coating of highly-aligned conjugated polymer thin films

DOE PAGES

Mohammadi, Erfan; Zhao, Chuankai; Meng, Yifei; ...

2017-07-13

Solution processable semiconducting polymers have been under intense investigations due to their diverse applications from printed electronics to biomedical devices. However, controlling the macromolecular assembly across length scales during solution coating remains a key challenge, largely due to the disparity in timescales of polymer assembly and high-throughput printing/coating. Herein we propose the concept of dynamic templating to expedite polymer nucleation and the ensuing assembly process, inspired by biomineralization templates capable of surface reconfiguration. Molecular dynamic simulations reveal that surface reconfigurability is key to promoting template–polymer interactions, thereby lowering polymer nucleation barrier. Employing ionic-liquid-based dynamic template during meniscus-guided coating results inmore » highly aligned, highly crystalline donor-acceptor polymer thin films over large area (41cm 2) and promoted charge transport along both the polymer backbone and the π-π stacking direction in field-effect transistors. We further demonstrate that the charge transport anisotropy can be reversed by tuning the degree of polymer backbone alignment.« less

The U.S. Geological Survey Climate Geo Data Portal: an integrated broker for climate and geospatial data

USGS Publications Warehouse

Blodgett, David L.

2013-01-01

The increasing availability of downscaled climate projections and other data products that summarize or predict climate conditions, is making climate data use more common in research and management. Scientists and decisionmakers often need to construct ensembles and compare climate hindcasts and future projections for particular spatial areas. These tasks generally require an investigator to procure all datasets of interest en masse, integrate the various data formats and representations into commonly accessible and comparable formats, and then extract the subsets of the datasets that are actually of interest. This process can be challenging and time intensive due to data-transfer, -storage, and(or) -processing limits, or unfamiliarity with methods of accessing climate data. Data management for modeling and assessing the impacts of future climate conditions is also becoming increasingly expensive due to the size of the datasets. The Climate Geo Data Portal (http://cida.usgs.gov/climate/gdp/) addresses these limitations, making access to numerous climate datasets for particular areas of interest a simple and efficient task.

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.

[Research & development and evaluation of oral films].

PubMed

Ren, Lian-Jie; Liu, Juan; Ma, Jun-Wei; Yan, Jia-Chen; Yin, Li-Fang

2017-10-01

Oral film is a new type of oral preparation. Due to portability, simple preparation process and good clinical compliance, oral films have become the focus of novel drug delivery system in recent years. Meanwhile, oral films have been gradually used in the development of Chinese medicine preparations. According to the application and approval situation of different types of oral films both at home and abroad in recent years, their research and development status was analyzed, including the basic concept, formulation, manufacturing process and quality control, as well as related progress and development prospects of oral films applied in traditional Chinese medicine. Some suggestions on the technical evaluation of oral films were put forward by considering specific requirements from regulatory agencies. This paper could provide some references for the development and evaluation of oral films. Due to the complexity of the drug substances and the particularity of the drug product, the development and application of oral films in traditional Chinese medicine are still faced with opportunity and challenges. Copyright© by the Chinese Pharmaceutical Association.

Challenges of caring for children with mental disorders: Experiences and views of caregivers attending the outpatient clinic at Muhimbili National Hospital, Dar es Salaam - Tanzania

PubMed Central

2012-01-01

Background It is estimated that world-wide up to 20 % of children suffer from debilitating mental illness. Mental disorders that pose a significant concern include learning disorders, hyperkinetic disorders (ADHD), depression, psychosis, pervasive development disorders, attachment disorders, anxiety disorders, conduct disorder, substance abuse and eating disorders. Living with such children can be very stressful for caregivers in the family. Therefore, determination of challenges of living with these children is important in the process of finding ways to help or support caregivers to provide proper care for their children. The purpose of this study was to explore the psychological and emotional, social, and economic challenges that parents or guardians experience when caring for mentally ill children and what they do to address or deal with them. Methodology A qualitative study design using in-depth interviews and focus group discussions was applied. The study was conducted at the psychiatric unit of Muhimbili National Hospital in Tanzania. Two focus groups discussions (FGDs) and 8 in-depth interviews were conducted with caregivers who attended the psychiatric clinic with their children. Data analysis was done using content analysis. Results The study revealed psychological and emotional, social, and economic challenges caregivers endure while living with mentally ill children. Psychological and emotional challenges included being stressed by caring tasks and having worries about the present and future life of their children. They had feelings of sadness, and inner pain or bitterness due to the disturbing behaviour of the children. They also experienced some communication problems with their children due to their inability to talk. Social challenges were inadequate social services for their children, stigma, burden of caring task, lack of public awareness of mental illness, lack of social support, and problems with social life. The economic challenges were poverty, child care interfering with various income generating activities in the family, and extra expenses associated with the child’s illness. Conclusion Caregivers of mentally ill children experience various psychological and emotional, social, and economic challenges. Professional assistance, public awareness of mental illnesses in children, social support by the government, private sector, and non-governmental organizations (NGOs) are important in addressing these challenges. PMID:22559084

Emerging topics in cutaneous wound repair.

PubMed

Valacchi, Giuseppe; Zanardi, Iacopo; Sticozzi, Claudia; Bocci, Velio; Travagli, Valter

2012-07-01

The intervention strategies in various types of skin wounds include several treatment programs that depend on the identified disease. Several factors such as aging, defective nutrition, traumatism, atherosclerosis, and diabetes may contribute to the formation of a wound that has no tendency to heal due to a defective and complicated repair process. The numerous advances in the understanding of the wound-healing process in both acute and chronic lesions have been recently described. The purpose of this paper is to describe relatively new approaches as viable alternatives to current wound-healing therapies. The future challenges for both the best targeting and optimization of these potential treatments are also described. © 2012 New York Academy of Sciences.

Plutonium Metallurgy

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

Freibert, Franz J.

2012-08-09

Due to its nuclear properties, Pu will remain a material of global interest well into the future. Processing, Structure, Properties and Performance remains a good framework for discussion of Pu materials science Self-irradiation and aging effects continue to be central in discussions of Pu metallurgy Pu in its elemental form is extremely unstable, but alloying helps to stabilize Pu; but, questions remain as to how and why this stabilization occurs. Which is true Pu-Ga binary phase diagram: US or Russian? Metallurgical issues such as solute coring, phase instability, crystallographic texture, etc. result in challenges to casting, processing, and properties modelingmore » and experiments. For Ga alloyed FCC stabilized Pu, temperature and pressure remain as variables impacting phase stability.« less

Depiction of interfacial morphology in impact welded Ti/Cu bimetallic systems using smoothed particle hydrodynamics

NASA Astrophysics Data System (ADS)

Nassiri, Ali; Vivek, Anupam; Abke, Tim; Liu, Bert; Lee, Taeseon; Daehn, Glenn

2017-06-01

Numerical simulations of high-velocity impact welding are extremely challenging due to the coupled physics and highly dynamic nature of the process. Thus, conventional mesh-based numerical methodologies are not able to accurately model the process owing to the excessive mesh distortion close to the interface of two welded materials. A simulation platform was developed using smoothed particle hydrodynamics, implemented in a parallel architecture on a supercomputer. Then, the numerical simulations were compared to experimental tests conducted by vaporizing foil actuator welding. The close correspondence of the experiment and modeling in terms of interface characteristics allows the prediction of local temperature and strain distributions, which are not easily measured.

Intravesical dosimetry applied to laser positioning in photodynamic therapy

NASA Astrophysics Data System (ADS)

Beslon, Guillaume; Ambroise, Philippe; Heit, Bernard; Bremont, Jacques; Guillemin, Francois H.

1996-12-01

Superficial bladder tumor is a challenging indication for photodynamic therapy. Due to lack of specificity of the sensitizers, the light has to be precisely monitored over the bladder surface, illuminated by an isotropic source, to restrict the cytotoxic effect to the tumor without affecting the normal epithelium. In order to assist the surgeon while processing the therapy, an urothelium illumination model is proposed. It is computed through a spline interpolation, on the basis of 12 intravesical sensors. This paper presents the overall system architecture and details the modelization and visualization processes. With this model, the surgeon is able to master the source displacement inside the bladder and to homogenize the tissue exposure.

Machinability of nickel based alloys using electrical discharge machining process

NASA Astrophysics Data System (ADS)

Khan, M. Adam; Gokul, A. K.; Bharani Dharan, M. P.; Jeevakarthikeyan, R. V. S.; Uthayakumar, M.; Thirumalai Kumaran, S.; Duraiselvam, M.

2018-04-01

The high temperature materials such as nickel based alloys and austenitic steel are frequently used for manufacturing critical aero engine turbine components. Literature on conventional and unconventional machining of steel materials is abundant over the past three decades. However the machining studies on superalloy is still a challenging task due to its inherent property and quality. Thus this material is difficult to be cut in conventional processes. Study on unconventional machining process for nickel alloys is focused in this proposed research. Inconel718 and Monel 400 are the two different candidate materials used for electrical discharge machining (EDM) process. Investigation is to prepare a blind hole using copper electrode of 6mm diameter. Electrical parameters are varied to produce plasma spark for diffusion process and machining time is made constant to calculate the experimental results of both the material. Influence of process parameters on tool wear mechanism and material removal are considered from the proposed experimental design. While machining the tool has prone to discharge more materials due to production of high energy plasma spark and eddy current effect. The surface morphology of the machined surface were observed with high resolution FE SEM. Fused electrode found to be a spherical structure over the machined surface as clumps. Surface roughness were also measured with surface profile using profilometer. It is confirmed that there is no deviation and precise roundness of drilling is maintained.

Precise Positioning of Uavs - Dealing with Challenging Rtk-Gps Measurement Conditions during Automated Uav Flights

NASA Astrophysics Data System (ADS)

Zimmermann, F.; Eling, C.; Klingbeil, L.; Kuhlmann, H.

2017-08-01

For some years now, UAVs (unmanned aerial vehicles) are commonly used for different mobile mapping applications, such as in the fields of surveying, mining or archeology. To improve the efficiency of these applications an automation of the flight as well as the processing of the collected data is currently aimed at. One precondition for an automated mapping with UAVs is that the georeferencing is performed directly with cm-accuracies or better. Usually, a cm-accurate direct positioning of UAVs is based on an onboard multi-sensor system, which consists of an RTK-capable (real-time kinematic) GPS (global positioning system) receiver and additional sensors (e.g. inertial sensors). In this case, the absolute positioning accuracy essentially depends on the local GPS measurement conditions. Especially during mobile mapping applications in urban areas, these conditions can be very challenging, due to a satellite shadowing, non-line-of sight receptions, signal diffraction or multipath effects. In this paper, two straightforward and easy to implement strategies will be described and analyzed, which improve the direct positioning accuracies for UAV-based mapping and surveying applications under challenging GPS measurement conditions. Based on a 3D model of the surrounding buildings and vegetation in the area of interest, a GPS geometry map is determined, which can be integrated in the flight planning process, to avoid GPS challenging environments as far as possible. If these challenging environments cannot be avoided, the GPS positioning solution is improved by using obstruction adaptive elevation masks, to mitigate systematic GPS errors in the RTK-GPS positioning. Simulations and results of field tests demonstrate the profit of both strategies.

Use of an ultrasonic reflectance technique to examine bubble size changes in dough

NASA Astrophysics Data System (ADS)

Strybulevych, A.; Leroy, V.; Shum, A. L.; Koksel, H. F.; Scanlon, M. G.; Page, J. H.

2012-12-01

Bread quality largely depends on the manner in which bubbles are created and manipulated in the dough during processing. We have developed an ultrasonic reflectance technique to monitor bubbles in dough, even at high volume fractions, where near the bubble resonances it is difficult to make measurements using transmission techniques. A broadband transducer centred at 3.5 MHz in a normal incidence wave reflection set-up is used to measure longitudinal velocity and attenuation from acoustic impedance measurements. The technique is illustrated by examining changes in bubbles in dough due to two very different physical effects. In dough made without yeast, a peak in attenuation due to bubble resonance is observed at approximately 2 MHz. This peak diminishes rapidly and shifts to lower frequencies, indicative of Ostwald ripening of bubbles within the dough. The second effect involves the growth of bubble sizes due to gas generated by yeast during fermentation. This process is experimentally challenging to investigate with ultrasound because of very high attenuation. The reflectance technique allows the changes of the velocity and attenuation during fermentation to be measured as a function of frequency and time, indicating bubble growth effects that can be monitored even at high volume fractions of bubbles.

Multi-scale sensitivity analysis of pile installation using DEM

NASA Astrophysics Data System (ADS)

Esposito, Ricardo Gurevitz; Velloso, Raquel Quadros; , Eurípedes do Amaral Vargas, Jr.; Danziger, Bernadete Ragoni

2017-12-01

The disturbances experienced by the soil due to the pile installation and dynamic soil-structure interaction still present major challenges to foundation engineers. These phenomena exhibit complex behaviors, difficult to measure in physical tests and to reproduce in numerical models. Due to the simplified approach used by the discrete element method (DEM) to simulate large deformations and nonlinear stress-dilatancy behavior of granular soils, the DEM consists of an excellent tool to investigate these processes. This study presents a sensitivity analysis of the effects of introducing a single pile using the PFC2D software developed by Itasca Co. The different scales investigated in these simulations include point and shaft resistance, alterations in porosity and stress fields and particles displacement. Several simulations were conducted in order to investigate the effects of different numerical approaches showing indications that the method of installation and particle rotation could influence greatly in the conditions around the numerical pile. Minor effects were also noted due to change in penetration velocity and pile-soil friction. The difference in behavior of a moving and a stationary pile shows good qualitative agreement with previous experimental results indicating the necessity of realizing a force equilibrium process prior to any load-test to be simulated.

Multi-scale sensitivity analysis of pile installation using DEM

NASA Astrophysics Data System (ADS)

Esposito, Ricardo Gurevitz; Velloso, Raquel Quadros; , Eurípedes do Amaral Vargas, Jr.; Danziger, Bernadete Ragoni

2018-07-01

The disturbances experienced by the soil due to the pile installation and dynamic soil-structure interaction still present major challenges to foundation engineers. These phenomena exhibit complex behaviors, difficult to measure in physical tests and to reproduce in numerical models. Due to the simplified approach used by the discrete element method (DEM) to simulate large deformations and nonlinear stress-dilatancy behavior of granular soils, the DEM consists of an excellent tool to investigate these processes. This study presents a sensitivity analysis of the effects of introducing a single pile using the PFC2D software developed by Itasca Co. The different scales investigated in these simulations include point and shaft resistance, alterations in porosity and stress fields and particles displacement. Several simulations were conducted in order to investigate the effects of different numerical approaches showing indications that the method of installation and particle rotation could influence greatly in the conditions around the numerical pile. Minor effects were also noted due to change in penetration velocity and pile-soil friction. The difference in behavior of a moving and a stationary pile shows good qualitative agreement with previous experimental results indicating the necessity of realizing a force equilibrium process prior to any load-test to be simulated.

Improved process robustness by using closed loop control in deep drawing applications

NASA Astrophysics Data System (ADS)

Barthau, M.; Liewald, M.; Christian, Held

2017-09-01

The production of irregular shaped deep-drawing parts with high quality requirements, which are common in today’s automotive production, permanently challenges production processes. High requirements on lightweight construction of passenger car bodies following European regulations until 2020 have been massively increasing the use of high strength steels substantially for years and are also leading to bigger challenges in sheet metal part production. Of course, the more and more complex shapes of today’s car body shells also intensify the issue due to modern and future design criteria. The metal forming technology tries to meet these challenges by developing a highly sophisticated layout of deep drawing dies that consider part quality requirements, process robustness and controlled material flow during the deep or stretch drawing process phase. A new method for controlling material flow using a closed loop system was developed at the IFU Stuttgart. In contrast to previous approaches, this new method allows a control intervention during the deep-drawing stroke. The blank holder force around the outline of the drawn part is used as control variable. The closed loop is designed as trajectory follow up with feed forward control. The used command variable is the part-wall stress that is measured with a piezo-electric measuring pin. In this paper the used control loop will be described in detail. The experimental tool that was built for testing the new control approach is explained here with its features. A method for gaining the follow up trajectories from simulation will also be presented. Furthermore, experimental results considering the robustness of the deep drawing process and the gain in process performance with developed control loop will be shown. Finally, a new procedure for the industrial application of the new control method of deep drawing will be presented by using a new kind of active element to influence the local blank holder pressure onto part flange.

Hydrologic impacts of thawing permafrost—A review

USGS Publications Warehouse

Walvoord, Michelle Ann; Kurylyk, Barret L.

2016-01-01

Where present, permafrost exerts a primary control on water fluxes, flowpaths, and distribution. Climate warming and related drivers of soil thermal change are expected to modify the distribution of permafrost, leading to changing hydrologic conditions, including alterations in soil moisture, connectivity of inland waters, streamflow seasonality, and the partitioning of water stored above and below ground. The field of permafrost hydrology is undergoing rapid advancement with respect to multiscale observations, subsurface characterization, modeling, and integration with other disciplines. However, gaining predictive capability of the many interrelated consequences of climate change is a persistent challenge due to several factors. Observations of hydrologic change have been causally linked to permafrost thaw, but applications of process-based models needed to support and enhance the transferability of empirical linkages have often been restricted to generalized representations. Limitations stem from inadequate baseline permafrost and unfrozen hydrogeologic characterization, lack of historical data, and simplifications in structure and process representation needed to counter the high computational demands of cryohydrogeologic simulations. Further, due in part to the large degree of subsurface heterogeneity of permafrost landscapes and the nonuniformity in thaw patterns and rates, associations between various modes of permafrost thaw and hydrologic change are not readily scalable; even trajectories of change can differ. This review highlights promising advances in characterization and modeling of permafrost regions and presents ongoing research challenges toward projecting hydrologic and ecologic consequences of permafrost thaw at time and spatial scales that are useful to managers and researchers.

Complex functional and epithetic rehabilitation after ablation of recurrent retroauricular basal cell carcinoma – a case study

PubMed Central

Reich, Waldemar; Exner, Anika; Winter, Eileen; Al-Nawas, Bilal; Eckert, Alexander Walter

2017-01-01

The reconstruction of extended defects of the concha poses a complex challenge for plastic surgeons. In cases of subtotal ablation, an alternative method designed especially for elderly oncological patients consists of epithetic rehabilitation. However, inserting an implant-retained concha epithesis proves challenging in patients with antecedents of deep resections involving the mastoid process. In the present case study, we report on the long-term treatment course (2009–2017) of a 79-year-old male patient suffering from a recurrent basal cell carcinoma of the retroauricular region. Following tumor resection, along with lateral mastoidectomy, reconstruction, and adjuvant radiotherapy, functional and esthetic deficits primarily due to peripheral facial nerve palsy were successfully managed using a multistep procedure. The procedure was completed by inserting an implant-retained concha epithesis, resulting in improved quality of life. Due to prior lateral mastoidectomy, ultra-short implants (4 mm) were inserted, partially at atypical positions. For maintaining healthy periimplant soft tissue, aftercare comprised cold plasma treatment. This oncologic case demonstrates the therapeutic necessity of using a broad spectrum of reconstructive procedures, along with their limitations, in a critical anatomic region. Specific features include the presentation of a workflow using ultra-short implants in a compromised mastoid region. Surgeons should consider alternative implant positions in the event of any compromised mastoid process. A particular emphasis has been put on meticulous aftercare to preserve healthy periimplant soft tissues. PMID:29423354

Laser heating challenges of high yield MagLIF targets

NASA Astrophysics Data System (ADS)

Slutz, Stephen; Sefkow, Adam; Vesey, Roger

2014-10-01

The MagLIF (Magnetized Liner Inertial Fusion) concept is predicted by numerical simulation to produce fusion yields of about 100 kJ, when driven by 25 MA from the existing Z accelerator [S. A. Slutz et al. Phys. Plasmas 17, 056303 (2010)] and much higher yields with future accelerators delivering higher currents [Slutz and Vesey PRL 108, 025003 (2012)]. The fuel must be heated before compression to obtain significant fusion yields due to the relatively slow implosion velocities (~ 100 km/s) of magnetically driven liners. Lasers provide a convenient means to accomplish this pre-compressional heating of the fusion fuel, but there are challenges. The laser must penetrate a foil covering the laser entrance hole and deposit 20-30 kJ within the ~1 cm length of the liner in fuel at 6-12 mg/cc. Such high densities could result in beam scattering due to refraction and laser plasma interactions. Numerical simulations of the laser heating process are presented, which indicate that energies as high as 30 kJ could be deposited in the fuel by using two laser pulses of different wavelengths. Simulations of this process will be presented as well of results for a MagLIF design for a potential new machine delivering 50 MA of current. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

Process Evaluation of Communitisation Programme in Public Sector Health Facilities, Mokokchung District, Nagaland, 2015.

PubMed

Tushi, Aonungdok; Kaur, Prabhdeep

2017-01-01

Public sector health facilities were poorly managed due to a history of conflict in Nagaland, India. Government of Nagaland introduced "Nagaland Communitisation of Public Institutions and Services Act" in 2002. Main objectives of the evaluation were to review the functioning of Health Center Managing Committees (HCMCs), deliver health services in the institutions managed by HCMC, identify strengths as well as challenges perceived by HCMC members in the rural areas of Mokokchung district, Nagaland. The evaluation was made using input, process and output indicators. A doctor, the HCMC Chairman and one member from each of the three community health centers (CHC) and four primary health centers (PHC) were surveyed using a semi-structured questionnaire and an in-depth interview guide. Proportions for quantitative data were computed and key themes from the same were identified. Overall; the infrastructure, equipment and outpatient/inpatient service availability was satisfactory. There was a lack of funds and shortage of doctors, drugs as well as laboratory facilities. HCMCs were in place and carried out administrative activities. HCMCs felt ownership, mobilized community contributions and managed human resources. HCMC members had inadequate funds for their transport and training. They faced challenges in service delivery due to political interference and lack of adequate human, material, financial resources. Communitisation program was operational in the district. HCMC members felt the ownership of health facilities. Administrative, political support and adequate funds from the government are needed for effective functioning of HCMCs and optimal service delivery in public sector facilities.

Peak water from glaciers: advances and challenges in a global perspective

NASA Astrophysics Data System (ADS)

Huss, M.; Hock, R.

2014-12-01

Mountain glaciers show a high sensitivity to changes in climate forcing. In a global perspective, their anticipated retreat will pose far-reaching challenges to the management of fresh water resources and will raise sea levels significantly within only a few decades. Different model frameworks have been applied to simulate melt water contributions of glaciers outside the two ice sheets for the recent IPCC report. However, these models depend on strongly simplified, and often empirical descriptions of the driving processes hampering the reliability of the results. Thus, a transition from the physically-based mass balance-ice flow models developed for single glaciers to the application at the global scale is urgently needed. The challenges are manifold but can be tackled with the new data sets, methods and process-understanding that have emerged during the last years. Here, we present a novel glacier model for calculating the response of surface mass balance and 3D glacier geometry for each individual glacier around the globe. Our approach accounts for feedbacks due to glacier retreat and includes models for mass loss due to frontal ablation and refreezing of water in the snow/firn. This allows the calculation of the components of proglacial runoff for each individual glacier in a process-based way. The current surface geometry and thickness distribution for each of the world's roughly 200'000 glaciers is extracted from the Randolph Glacier Inventory v3.3 and terrain models. Our simulations are driven with 14 Global Circulation Models from the CMIP5 project using the RCP4.5, RCP8.5 and RCP2.6 scenarios. We focus on the timing of peak water from glacierized catchments in all climatic regions of the earth and the corresponding importance of these regime changes on hydrological stress. Peak water represents a crucial tipping point for sustained water supply even for regions with only a minor glacier coverage, and is relevant to the dynamics of sea level rise. The maximum rate of water release from glacial storage is subject to a high spatio-temporal variability depending on the glacier-specific geometry and its transient response to climatic change.

Application of a distributed systems architecture for increased speed in image processing on an autonomous ground vehicle

NASA Astrophysics Data System (ADS)

Wright, Adam A.; Momin, Orko; Shin, Young Ho; Shakya, Rahul; Nepal, Kumud; Ahlgren, David J.

2010-01-01

This paper presents the application of a distributed systems architecture to an autonomous ground vehicle, Q, that participates in both the autonomous and navigation challenges of the Intelligent Ground Vehicle Competition. In the autonomous challenge the vehicle is required to follow a course, while avoiding obstacles and staying within the course boundaries, which are marked by white lines. For the navigation challenge, the vehicle is required to reach a set of target destinations, known as way points, with given GPS coordinates and avoid obstacles that it encounters in the process. Previously the vehicle utilized a single laptop to execute all processing activities including image processing, sensor interfacing and data processing, path planning and navigation algorithms and motor control. National Instruments' (NI) LabVIEW served as the programming language for software implementation. As an upgrade to last year's design, a NI compact Reconfigurable Input/Output system (cRIO) was incorporated to the system architecture. The cRIO is NI's solution for rapid prototyping that is equipped with a real time processor, an FPGA and modular input/output. Under the current system, the real time processor handles the path planning and navigation algorithms, the FPGA gathers and processes sensor data. This setup leaves the laptop to focus on running the image processing algorithm. Image processing as previously presented by Nepal et. al. is a multi-step line extraction algorithm and constitutes the largest processor load. This distributed approach results in a faster image processing algorithm which was previously Q's bottleneck. Additionally, the path planning and navigation algorithms are executed more reliably on the real time processor due to the deterministic nature of operation. The implementation of this architecture required exploration of various inter-system communication techniques. Data transfer between the laptop and the real time processor using UDP packets was established as the most reliable protocol after testing various options. Improvement can be made to the system by migrating more algorithms to the hardware based FPGA to further speed up the operations of the vehicle.

Bioengineering approaches to study multidrug resistance in tumor cells

PubMed Central

Fallica, Brian; Makin, Guy

2015-01-01

The ability of cancer cells to become resistant to chemotherapeutic agents is a major challenge for the treatment of malignant tumors. Several strategies have emerged to attempt to inhibit chemoresistance, but the fact remains that resistance is a problem for every effective anticancer drug. The first part of this review will focus on the mechanisms of chemoresistance. It is important to understand the environmental cues, transport limitations and the cellular signaling pathways associated with chemoresistance before we can hope to effectively combat it. The second part of this review focuses on the work that needs to be done moving forward. Specifically, this section focuses on the necessity of translational research and interdisciplinary directives. It is critical that the expertise of oncologists, biologists, and engineers be brought together to attempt to tackle the problem. This discussion is from an engineering perspective, as the dialogue between engineers and other cancer researchers is the most challenging due to non-overlapping background knowledge. Chemoresistance is a complex and devastating process, meaning that we urgently need sophisticated methods to study the process of how cells become resistant. PMID:21387035

Design of the Williams Field Services Mobile Bay ethane recovery plant

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

Vogel, D.C.; McKenzie, D.

1999-07-01

ABB Randall designed, procured and constructed a two train expander plant with a base case design capacity of 525 MMscfd and a hydraulic design capacity of 600 MMscfd. Randall has used its Recycle Reflux Process, proven in other installations, resulting in a calculated ethane recovery of 93% at 525 MMscfd (78% at 600 MMscfd) and ethane rejection. Liquids production creates a design challenge due to the presence of acid gas components such as CO{sub 2}, H{sub 2}S, mercaptans and COS, with the latter three causing the product to fail the copper strip test. The challenge is to remove the componentsmore » to the required level with minimum cost and in an operator-friendly manner. The following combinations of processes were reviewed: DGA, MDEA and Merichem, COS Hydrolysis and MDEA, MDEA and KOH, Sulfinol, MDEA and SulfaClean; and MDEA and mol sieve. This paper will give a brief description, an illustration and economic impact information of each one. Lastly, the rationale behind the selection of the COS Hydrolysis bed, MDEA absorber and provisions to add an iron sponge bed is discussed.« less

Chip Design Process Optimization Based on Design Quality Assessment

NASA Astrophysics Data System (ADS)

Häusler, Stefan; Blaschke, Jana; Sebeke, Christian; Rosenstiel, Wolfgang; Hahn, Axel

2010-06-01

Nowadays, the managing of product development projects is increasingly challenging. Especially the IC design of ASICs with both analog and digital components (mixed-signal design) is becoming more and more complex, while the time-to-market window narrows at the same time. Still, high quality standards must be fulfilled. Projects and their status are becoming less transparent due to this complexity. This makes the planning and execution of projects rather difficult. Therefore, there is a need for efficient project control. A main challenge is the objective evaluation of the current development status. Are all requirements successfully verified? Are all intermediate goals achieved? Companies often develop special solutions that are not reusable in other projects. This makes the quality measurement process itself less efficient and produces too much overhead. The method proposed in this paper is a contribution to solve these issues. It is applied at a German design house for analog mixed-signal IC design. This paper presents the results of a case study and introduces an optimized project scheduling on the basis of quality assessment results.

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.

Underwater microscopy for in situ studies of benthic ecosystems

NASA Astrophysics Data System (ADS)

Mullen, Andrew D.; Treibitz, Tali; Roberts, Paul L. D.; Kelly, Emily L. A.; Horwitz, Rael; Smith, Jennifer E.; Jaffe, Jules S.

2016-07-01

Microscopic-scale processes significantly influence benthic marine ecosystems such as coral reefs and kelp forests. Due to the ocean's complex and dynamic nature, it is most informative to study these processes in the natural environment yet it is inherently difficult. Here we present a system capable of non-invasively imaging seafloor environments and organisms in situ at nearly micrometre resolution. We overcome the challenges of underwater microscopy through the use of a long working distance microscopic objective, an electrically tunable lens and focused reflectance illumination. The diver-deployed instrument permits studies of both spatial and temporal processes such as the algal colonization and overgrowth of bleaching corals, as well as coral polyp behaviour and interspecific competition. By enabling in situ observations at previously unattainable scales, this instrument can provide important new insights into micro-scale processes in benthic ecosystems that shape observed patterns at much larger scales.

Challenges in Laser Sintering of Melt-Processable Thermoset Imide Resin

NASA Technical Reports Server (NTRS)

Chuang, Kathy C.; Gornet, Timothy; Koerner, Hilmar

2016-01-01

Polymer Laser Sintering (LS) is an additive manufacturing technique that builds 3D models layer by layer using a laser to selectively melt cross sections in powdered polymeric materials, following sequential slices of the CAD model. LS generally uses thermoplastic polymeric powders, such as polyamides (i.e. Nylon), and the resultant 3D objects are often weaker in their strength compared to traditionally processed materials, due to the lack of polymer inter-chain connection in the z-direction. The objective of this project is to investigate the possibility of printing a melt-processable RTM370 imide resin powder terminated with reactive phenylethynyl groups by LS, followed by a postcure in order to promote additional crosslinking to achieve higher temperature (250-300 C) capability. A preliminary study to build tensile specimens by LS and the corresponding DSC and rheology study of RTM370 during LS process is presented.

Rethinking exploitation: a process-centered account.

PubMed

Jansen, Lynn A; Wall, Steven

2013-12-01

Exploitation has become an important topic in recent discussions of biomedical and research ethics. This is due in no small measure to the influence of Alan Wertheimer's path-breaking work on the subject. This paper presents some objections to Wertheimer's account of the concept. The objections attempt to show that his account places too much emphasis on outcome-based considerations and too little on process-based considerations. Building on these objections, the paper develops an alternative process-centered account of the concept. This alternative account of exploitation takes as its point of departure the broadly Kantian notion that it is wrong to use another as an instrument for the advancement of one's own ends. It sharpens this slippery notion and adds a number of refinements to it. The paper concludes by arguing that process-centered accounts of exploitation better illuminate the ethical challenges posed by research on human subjects than outcome-centered accounts.

Simulation and optimization of an experimental membrane wastewater treatment plant using computational intelligence methods.

PubMed

Ludwig, T; Kern, P; Bongards, M; Wolf, C

2011-01-01

The optimization of relaxation and filtration times of submerged microfiltration flat modules in membrane bioreactors used for municipal wastewater treatment is essential for efficient plant operation. However, the optimization and control of such plants and their filtration processes is a challenging problem due to the underlying highly nonlinear and complex processes. This paper presents the use of genetic algorithms for this optimization problem in conjunction with a fully calibrated simulation model, as computational intelligence methods are perfectly suited to the nonconvex multi-objective nature of the optimization problems posed by these complex systems. The simulation model is developed and calibrated using membrane modules from the wastewater simulation software GPS-X based on the Activated Sludge Model No.1 (ASM1). Simulation results have been validated at a technical reference plant. They clearly show that filtration process costs for cleaning and energy can be reduced significantly by intelligent process optimization.

Ultrafiltration of hemicellulose hydrolysate fermentation broth

NASA Astrophysics Data System (ADS)

Kresnowati, M. T. A. P.; Desiriani, Ria; Wenten, I. G.

2017-03-01

Hemicelulosic material is often used as the main substrate to obtain high-value products such as xylose. The five carbon sugar, xylose, could be further processed by fermentation to produce xylitol. However, not only the hemicellulose hydrolysate fermentation broth contains xylitol, but also metabolite products, residual substances, biomass and mineral salts. Therefore, in order to obtain the end products, various separation processes are required to separate and purify the desired product from the fermentation broth. One of the most promising downstream processing methods of fermentation broth clarification is ultrafiltration due to its potential for energy saving and higher purity. In addition, ultrafiltration membrane has a high performance in separating inhibitory components in the fermentation broth. This paper assesses the influence of operating conditions; including trans-membrane pressure, velocity, pH of the fermentation broth solutions, and also to the xylitol concentration in the product. The challenges of the ultrafiltration process will be pointed out.

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.

[The Articulator of Primary Health Care Program: an innovative proposal for qualification of Primary Health Care].

PubMed

Doricci, Giovanna Cabral; Guanaes-Lorenzi, Carla; Pereira, Maria José Bistafa

2017-06-01

In 2009, the Secretary of State for Health of Sao Paulo created a Program with a view to qualify the primary care in the state. This proposal includes a new job function, namely the articulator of primary care. Due to the scarcity of information about the practice of these new professionals in the scientific literature, this article seeks to analyze how articulators interpret their function and how they describe their daily routines. Thirteen articulators were interviewed. The interviews were duly analyzed by qualitative delineation. The results describe three themes: 1)Roles of the articulator: technical communicator and political advisor; 2) Activities performed to comply with the expected roles, examples being diagnosis of the municipalities, negotiation of proposals, participation in meetings, visits to municipalities; and 3) Challenges of the role, which are configured as challenges to the health reform process, examples being the lack of physical and human resources, activities of professionals in the medical-centered model, among others. The conclusion drawn is that the Program has great potential to provide input for the development and enhancement of Primary Care. Nevertheless, there are a series of challenges to be overcome, namely challenges to the context per se.

Socio-economic and cultural vulnerabilities to cervical cancer and challenges faced by patients attending care at Tikur Anbessa Hospital: a cross sectional and qualitative study.

PubMed

Tadesse, Sara Kebede

2015-09-16

Cervical cancer is a leading cause of death among women in Ethiopia, affecting them at a time of their life when they are critical to social and economic stability. This study was mainly focused on assessing different socioeconomic and cultural related factors that make women vulnerable to cervical cancer and challenges women face in the process of diagnosis and treatment. To achieve the objective of the study both qualitative and quantitative methods were utilized.198 participants were enrolled in a cross- sectional survey and 10 in-depth interviews were conducted with patients in Tikur Anbessa Hospital. A consecutive sampling method was used to select participants in the survey while purposive sampling was employed to select participants in the qualitative design. For the population covered in the study, poverty along with other socio-cultural practices such as early marriage, high parity and to certain extent polygamy were identified as factors that increased the vulnerability of women to cervical cancer. In addition, the study has uncovered several challenges faced by cervical cancer patients in the diagnosis and treatment process. Three types of challenges that include, health care based, psychological and economic were identified. System and practitioner delay were found as the main hurdles within the variable of health care related challenges. What's more, the psychological challenges identified included, fear of recurrence, negative social attitude and distress associated with the side effects from treatments such as fecal & urinary leakage. Furthermore, inability of bearing costs related to treatment and accommodation were cited as the main economic challenges. The study showed various socio-economic and cultural vulnerabilities that expose women to cervical cancer and the challenges encountered by cervical cancer patients after their diagnosis. Addressing this issue largely lies in strengthening primary and secondary preventive mechanisms, providing public education about safer sex practices, family planning and eliminating cultural practices such as early marriage and polygamy in connection to cervical cancer. Furthermore, improving the diagnostic and treatment procedures and facilities is also a crucial component that needs due emphasis in the fight against cervical cancer.

Optimization of insect cell based protein production processes - online monitoring, expression systems, scale up.

PubMed

Druzinec, Damir; Salzig, Denise; Brix, Alexander; Kraume, Matthias; Vilcinskas, Andreas; Kollewe, Christian; Czermak, Peter

2013-01-01

Due to the increasing use of insect cell based expression systems in research and industrial recombinant protein production, the development of efficient and reproducible production processes remains a challenging task. In this context, the application of online monitoring techniques is intended to ensure high and reproducible product qualities already during the early phases of process development. In the following chapter, the most common transient and stable insect cell based expression systems are briefly introduced. Novel applications of insect cell based expression systems for the production of insect derived antimicrobial peptides/proteins (AMPs) are discussed using the example of G. mellonella derived gloverin. Suitable in situ sensor techniques for insect cell culture monitoring in disposable and common bioreactor systems are outlined with respect to optical and capacitive sensor concepts. Since scale up of production processes is one of the most critical steps in process development, a conclusive overview is given about scale up aspects for industrial insect cell culture processes.

Virtual tryout planning in automotive industry based on simulation metamodels

NASA Astrophysics Data System (ADS)

Harsch, D.; Heingärtner, J.; Hortig, D.; Hora, P.

2016-11-01

Deep drawn sheet metal parts are increasingly designed to the feasibility limit, thus achieving a robust manufacturing is often challenging. The fluctuation of process and material properties often lead to robustness problems. Therefore, numerical simulations are used to detect the critical regions. To enhance the agreement with the real process conditions, the material data are acquired through a variety of experiments. Furthermore, the force distribution is taken into account. The simulation metamodel contains the virtual knowledge of a particular forming process, which is determined based on a series of finite element simulations with variable input parameters. Based on the metamodels, virtual process windows can be displayed for different configurations. This helps to improve the operating point as well as to adjust process settings in case the process becomes unstable. Furthermore, the time of tool tryout can be shortened due to transfer of the virtual knowledge contained in the metamodels on the optimisation of the drawbeads. This allows the tool manufacturer to focus on the essential, to save time and to recognize complex relationships.

Nanocharacterization Challenges in a Changing Microelectronics Landscape

NASA Astrophysics Data System (ADS)

Brilloüt, Michel

2011-11-01

As the microelectronics industry enters the "nano"-era new challenges emerge. Traditional scaling of the MOS transistor faces major obstacles in fulfilling "Moore's law". New features like strain and new materials (e.g. high k—metal gate stack) are introduced in order to sustain performance increases. For a better electrostatic control, devices will use the third dimension, e.g., in gate-all-around nanowire structures. Due to the escalating cost and complexity of sub-28 nm technologies fewer industrial players can afford the development and production of advanced CMOS processes and many companies acknowledge the fact that the value in products can also be obtained in using more diversified non-digital technologies (the so-called "More-than-Moore" domain). This evolving landscape brings new requirements—discussed in this paper—in terms of physical characterization of technologies and devices.

Opto-Mechanics of the Constellation-X SXT Mirrors: Challenges in Mounting and Assembling the Mirror Segments

NASA Technical Reports Server (NTRS)

Chan, Kai-Wing; Zhang, WIlliam W.; Saha, Timo; Lehan, John P.; Mazzarella, James; Lozipone, Lawrence; Hong, Melinda; Byron, Glenn

2008-01-01

The Constellation-X Spectroscopy X-Ray Telescopes consists of segmented glass mirrors with an axial length of 200 mm, a width of up to 400 mm, and a thickness of 0.4 mm. To meet the requirement of less than 15 arc-second half-power diameter with the small thickness and relatively large size is a tremendous challenge in opto-mechanics. How shall we limit distortion of the mirrors due to gravity in ground tests, that arises from thermal stress, and that occurs in the process of mounting, affixing and assembling of these mirrors? In this paper, we will describe our current opto-mechanical approach to these problems. We will discuss, in particular, the approach and experiment where the mirrors are mounted vertically by first suspending it at two points.

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.

Carbon Nanotube Thin Film Transistors for Flat Panel Display Application.

PubMed

Liang, Xuelei; Xia, Jiye; Dong, Guodong; Tian, Boyuan; Peng, Lianmao

2016-12-01

Carbon nanotubes (CNTs) are promising materials for both high performance transistors for high speed computing and thin film transistors for macroelectronics, which can provide more functions at low cost. Among macroelectronics applications, carbon nanotube thin film transistors (CNT-TFT) are expected to be used soon for backplanes in flat panel displays (FPDs) due to their superior performance. In this paper, we review the challenges of CNT-TFT technology for FPD applications. The device performance of state-of-the-art CNT-TFTs are compared with the requirements of TFTs for FPDs. Compatibility of the fabrication processes of CNT-TFTs and current TFT technologies are critically examined. Though CNT-TFT technology is not yet ready for backplane production line of FPDs, the challenges can be overcome by close collaboration between research institutes and FPD manufacturers in the short term.

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

Construction of a nontoxigenic Clostridium botulinum strain for food challenge studies.

PubMed

Bradshaw, Marite; Marshall, Kristin M; Heap, John T; Tepp, William H; Minton, Nigel P; Johnson, Eric A

2010-01-01

Clostridium botulinum produces the most poisonous natural toxin known and is a perennial concern to the food industry and to regulatory agencies due to the potential threat of food-borne botulism. To ensure the botulinal safety of foods, rigorous food challenge testing to validate food-processing conditions and food formulations has been routinely performed. Detection of the botulinum neurotoxin is performed by using a mouse bioassay and/or in vitro assays. There has been considerable interest by the food industry and regulatory agencies in minimizing or even replacing the use of animals in these challenge studies. In addition, due to stringent select-agent regulations, the testing of various foods using toxigenic C. botulinum strains requires facilities and personnel that are certified for work with this organism. For this purpose we propose to generate sets of nontoxigenic C. botulinum strains from proteolytic and nonproteolytic groups that differ from the wild-type strains only by their inability to produce botulinum neurotoxin. In this initial study we describe the generation of a nontoxigenic mutant of C. botulinum strain 62A using the ClosTron mutagenesis system by inserting a group II intron into the botulinum neurotoxin type A gene (bont/A). The mutant clones were nontoxigenic as determined by Western blots and mouse bioassays but showed physiological characteristics, including growth properties and sporulation, that were similar to those of the parent strain in laboratory media. Additional studies will be required to evaluate comparable characteristics in various food matrices. The availability of suitable nontoxigenic C. botulinum strains for food challenge studies will be beneficial for enhancing the botulinal safety of foods as well as increasing the biosafety of workers and may eliminate the use of laboratory animals.

A generic biogeochemical module for earth system models

NASA Astrophysics Data System (ADS)

Fang, Y.; Huang, M.; Liu, C.; Li, H.-Y.; Leung, L. R.

2013-06-01

Physical and biogeochemical processes regulate soil carbon dynamics and CO2 flux to and from the atmosphere, influencing global climate changes. Integration of these processes into earth system models (e.g. community land models - CLM), however, currently faces three major challenges: (1) extensive efforts are required to modify modeling structures and to rewrite computer programs to incorporate new or updated processes as new knowledge is being generated, (2) computational cost is prohibitively expensive to simulate biogeochemical processes in land models due to large variations in the rates of biogeochemical processes, and (3) various mathematical representations of biogeochemical processes exist to incorporate different aspects of fundamental mechanisms, but systematic evaluation of the different mathematical representations is difficult, if not impossible. To address these challenges, we propose a new computational framework to easily incorporate physical and biogeochemical processes into land models. The new framework consists of a new biogeochemical module with a generic algorithm and reaction database so that new and updated processes can be incorporated into land models without the need to manually set up the ordinary differential equations to be solved numerically. The reaction database consists of processes of nutrient flow through the terrestrial ecosystems in plants, litter and soil. This framework facilitates effective comparison studies of biogeochemical cycles in an ecosystem using different conceptual models under the same land modeling framework. The approach was first implemented in CLM and benchmarked against simulations from the original CLM-CN code. A case study was then provided to demonstrate the advantages of using the new approach to incorporate a phosphorus cycle into the CLM model. To our knowledge, the phosphorus-incorporated CLM is a new model that can be used to simulate phosphorus limitation on the productivity of terrestrial ecosystems.

Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System

PubMed Central

Bhudolia, Somen K.; Perrotey, Pavel; Joshi, Sunil C.

2017-01-01

For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs) composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA) thermoplastic matrix, Elium®. Vacuum assisted resin infusion (VARI) process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS) and NCF with novel reactive thermoplastic (TP) resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented. PMID:28772654

Optimizing Polymer Infusion Process for Thin Ply Textile Composites with Novel Matrix System.

PubMed

Bhudolia, Somen K; Perrotey, Pavel; Joshi, Sunil C

2017-03-15

For mass production of structural composites, use of different textile patterns, custom preforming, room temperature cure high performance polymers and simplistic manufacturing approaches are desired. Woven fabrics are widely used for infusion processes owing to their high permeability but their localised mechanical performance is affected due to inherent associated crimps. The current investigation deals with manufacturing low-weight textile carbon non-crimp fabrics (NCFs) composites with a room temperature cure epoxy and a novel liquid Methyl methacrylate (MMA) thermoplastic matrix, Elium ® . Vacuum assisted resin infusion (VARI) process is chosen as a cost effective manufacturing technique. Process parameters optimisation is required for thin NCFs due to intrinsic resistance it offers to the polymer flow. Cycles of repetitive manufacturing studies were carried out to optimise the NCF-thermoset (TS) and NCF with novel reactive thermoplastic (TP) resin. It was noticed that the controlled and optimised usage of flow mesh, vacuum level and flow speed during the resin infusion plays a significant part in deciding the final quality of the fabricated composites. The material selections, the challenges met during the manufacturing and the methods to overcome these are deliberated in this paper. An optimal three stage vacuum technique developed to manufacture the TP and TS composites with high fibre volume and lower void content is established and presented.

Factors influencing intercultural doctor-patient communication: a realist review.

PubMed

Paternotte, Emma; van Dulmen, Sandra; van der Lee, Nadine; Scherpbier, Albert J J A; Scheele, Fedde

2015-04-01

Due to migration, doctors see patients from different ethnic backgrounds. This causes challenges for the communication. To develop training programs for doctors in intercultural communication (ICC), it is important to know which barriers and facilitators determine the quality of ICC. This study aimed to provide an overview of the literature and to explore how ICC works. A systematic search was performed to find literature published before October 2012. The search terms used were cultural, communication, healthcare worker. A realist synthesis allowed us to use an explanatory focus to understand the interplay of communication. In total, 145 articles met the inclusion criteria. We found ICC challenges due to language, cultural and social differences, and doctors' assumptions. The mechanisms were described as factors influencing the process of ICC and divided into objectives, core skills and specific skills. The results were synthesized in a framework for the development of training. The quality of ICC is influenced by the context and by the mechanisms. These mechanisms translate into practical points for training, which seem to have similarities with patient-centered communication. Training for improving ICC can be developed as an extension of the existing training for patient-centered communication. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Executing SPARQL Queries over the Web of Linked Data

NASA Astrophysics Data System (ADS)

Hartig, Olaf; Bizer, Christian; Freytag, Johann-Christoph

The Web of Linked Data forms a single, globally distributed dataspace. Due to the openness of this dataspace, it is not possible to know in advance all data sources that might be relevant for query answering. This openness poses a new challenge that is not addressed by traditional research on federated query processing. In this paper we present an approach to execute SPARQL queries over the Web of Linked Data. The main idea of our approach is to discover data that might be relevant for answering a query during the query execution itself. This discovery is driven by following RDF links between data sources based on URIs in the query and in partial results. The URIs are resolved over the HTTP protocol into RDF data which is continuously added to the queried dataset. This paper describes concepts and algorithms to implement our approach using an iterator-based pipeline. We introduce a formalization of the pipelining approach and show that classical iterators may cause blocking due to the latency of HTTP requests. To avoid blocking, we propose an extension of the iterator paradigm. The evaluation of our approach shows its strengths as well as the still existing challenges.

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

Online Adaptive Radiation Therapy: Implementation of a New Process of Care

PubMed Central

Cao, Minsong; Kishan, Amar; Agazaryan, Nzhde; Thomas, David H; Shaverdian, Narek; Yang, Yingli; Ray, Suzette; Low, Daniel A; Raldow, Ann; Steinberg, Michael L.; Lee, Percy

2017-01-01

Onboard magnetic resonance imaging (MRI) guided radiotherapy is now clinically available in nine centers in the world. This technology has facilitated the clinical implementation of online adaptive radiotherapy (OART), or the ability to alter the daily treatment plan based on tumor and anatomical changes in real-time while the patient is on the treatment table. However, due to the time sensitive nature of OART, implementation in a large and busy clinic has many potential obstacles as well as patient-related safety considerations. In this work, we have described the implementation of this new process of care in the Department of Radiation Oncology at the University of California, Los Angeles (UCLA). We describe the rationale, the initial challenges such as treatment time considerations, technical issues during the process of re-contouring, re-optimization, quality assurance, as well as our current solutions to overcome these challenges. In addition, we describe the implementation of a coverage system with a physician of the day as well as online planners (physicists or dosimetrists) to oversee each OART treatment with patient-specific ‘hand-off’ directives from the patient’s treating physician. The purpose of this effort is to streamline the process without compromising treatment quality and patient safety. As more MRI-guided radiotherapy programs come online, we hope that our experience can facilitate successful adoption of OART in a way that maximally benefits the patient. PMID:29104835

Comparing the role of selective and divided attention in the composite face effect: Insights from Attention Operating Characteristic (AOC) plots and cross-contingency correlations.

PubMed

Fitousi, Daniel

2016-03-01

Composite faces combine the top half of one face with the bottom half of another to create a compelling illusion of a new face. Evidence for holistic processing with composite faces comes primarily from a matching procedure in a selective attention task. In the present study, a dual-task approach has been employed to study whether composite faces reflect genuine holistic (i.e., fusion of parts) or non-holistic processing strategies (i.e., switching, resource sharing). This has been accomplished by applying the Attention Operation Characteristic methodology (AOC, Sperling & Melchner, 1978a, 1978b) and cross-contingency correlations (Bonnel & Prinzmetal, 1998) to composite faces. Overall, the results converged on the following conclusions: (a) observers can voluntarily allocate differential amounts of attention to the top and bottom parts in both spatially aligned and misaligned composite faces, (b) the interaction between composite face halves is due to attentional limitations, not due to switching or fusion strategies, and (c) the processing of aligned and misaligned composite faces is quantitatively and qualitatively similar. Taken together, these results challenge the holistic interpretation of the composite face illusion. Copyright © 2015 Elsevier B.V. All rights reserved.

Decentralized system identification using stochastic subspace identification on wireless smart sensor networks

NASA Astrophysics Data System (ADS)

Sim, Sung-Han; Spencer, Billie F., Jr.; Park, Jongwoong; Jung, Hyungjo

2012-04-01

Wireless Smart Sensor Networks (WSSNs) facilitates a new paradigm to structural identification and monitoring for civil infrastructure. Conventional monitoring systems based on wired sensors and centralized data acquisition and processing have been considered to be challenging and costly due to cabling and expensive equipment and maintenance costs. WSSNs have emerged as a technology that can overcome such difficulties, making deployment of a dense array of sensors on large civil structures both feasible and economical. However, as opposed to wired sensor networks in which centralized data acquisition and processing is common practice, WSSNs require decentralized computing algorithms to reduce data transmission due to the limitation associated with wireless communication. Thus, several system identification methods have been implemented to process sensor data and extract essential information, including Natural Excitation Technique with Eigensystem Realization Algorithm, Frequency Domain Decomposition (FDD), and Random Decrement Technique (RDT); however, Stochastic Subspace Identification (SSI) has not been fully utilized in WSSNs, while SSI has the strong potential to enhance the system identification. This study presents a decentralized system identification using SSI in WSSNs. The approach is implemented on MEMSIC's Imote2 sensor platform and experimentally verified using a 5-story shear building model.

An ultrasensitive bio-surrogate for nanoporous filter membrane performance metrology directed towards contamination control in microlithography applications

NASA Astrophysics Data System (ADS)

Ahmad, Farhan; Mish, Barbara; Qiu, Jian; Singh, Amarnauth; Varanasi, Rao; Bedford, Eilidh; Smith, Martin

2016-03-01

Contamination tolerances in semiconductor manufacturing processes have changed dramatically in the past two decades, reaching below 20 nm according to the guidelines of the International Technology Roadmap for Semiconductors. The move to narrower line widths drives the need for innovative filtration technologies that can achieve higher particle/contaminant removal performance resulting in cleaner process fluids. Nanoporous filter membrane metrology tools that have been the workhorse over the past decade are also now reaching limits. For example, nanoparticle (NP) challenge testing is commonly applied for assessing particle retention performance of filter membranes. Factors such as high NP size dispersity, low NP detection sensitivity, and high NP particle-filter affinity impose challenges in characterizing the next generation of nanoporous filter membranes. We report a novel bio-surrogate, 5 nm DNA-dendrimer conjugate for evaluating particle retention performance of nanoporous filter membranes. A technique capable of single molecule detection is employed to detect sparse concentration of conjugate in filter permeate, providing >1000- fold higher detection sensitivity than any existing 5 nm-sized particle enumeration technique. This bio-surrogate also offers narrow size distribution, high stability and chemical tunability. This bio-surrogate can discriminate various sub-15 nm pore-rated nanoporous filter membranes based on their particle retention performance. Due to high bio-surrogate detection sensitivity, a lower challenge concentration of bio-surrogate (as compared to other NPs of this size) can be used for filter testing, providing a better representation of customer applications. This new method should provide better understanding of the next generation filter membranes for removing defect-causing contaminants from lithography processes.

Using pedagogical approaches to influence evidence-based practice integration - processes and recommendations: findings from a grounded theory study.

PubMed

Malik, Gulzar; McKenna, Lisa; Griffiths, Debra

2017-04-01

The study aimed to explore the processes undertaken by nurse academics when integrating evidence-based practice (EBP) into their teaching and learning practices. This article focuses on pedagogical approaches employed by academics to influence evidence-based practice integration into undergraduate programs across Australian universities. Nursing academics are challenged to incorporate a variety of teaching and learning strategies to teach evidence-based practice and determine their effectiveness. However, literature suggests that there are limited studies available focusing on pedagogical approaches in evidence-based practice education. A constructivist grounded theory methodology, informed by Charmaz was used for this study. Data were collected during 2014 from 23 nurse academics across Australian universities through semi-structured interviews. Additionally, nine were observed during teaching of undergraduate students. Twenty subject outlines were also analysed following Charmaz's approach of data analysis. 'Influencing EBP integration' describes the pedagogical approaches employed by academics to incorporate EBP knowledge and skills into undergraduate curricula. With the use of various teaching and learning strategies, academics attempted to contextualize EBP by engaging students with activities aiming to link evidence to practice and with the EBP process. Although, some strategies appeared to be engaging, others were traditional and seemed to be disengaging for students due to the challenges experienced by participants that impeded the use of the most effective teaching methods. Study findings offer valuable insights into the teaching practices and identify some key challenges that require the adoption of appropriate strategies to ensure future nurses are well prepared in the paradigm of evidence-based practice. © 2016 John Wiley & Sons Ltd.

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

NASA Technical Reports Server (NTRS)

Stephan, Ryan A.

2011-01-01

The now-cancelled Constellation Program included the Orion, Altair, and Lunar Surface Systems project offices. The first two elements, Orion and Altair, were planned to be manned space vehicles while the third element was much more diverse and included several sub-elements. Among other things, these sub-elements were Rovers and a Lunar Habitat. The planned missions involving these systems and vehicles included several risks and design challenges. Due to the unique thermal operating environment, many of these risks and challenges were associated with the vehicles thermal control system. NASA s Exploration Technology Development Program (ETDP) consisted of various technology development projects. The project chartered with mitigating the aforementioned thermal risks and design challenges was the Thermal Control System Development for Exploration Project. These risks and design challenges were being addressed through a rigorous technology development process that was planned to culminate with an integrated thermal control system test. Although the technologies being developed were originally aimed towards mitigating specific Constellation risks, the technology development process is being continued within a new program. This continued effort is justified by the fact that many of the technologies are generically applicable to future spacecraft thermal control systems. The current 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 a material compatibility assessment for a promising thermal control system working fluid. The to-date progress and lessons-learned from these development efforts will be discussed throughout the paper.

Application of science-based restoration planning to a desert river system.

PubMed

Laub, Brian G; Jimenez, Justin; Budy, Phaedra

2015-06-01

Persistence of many desert river species is threatened by a suite of impacts linked to water infrastructure projects that provide human water security where water is scarce. Many desert rivers have undergone regime shifts from spatially and temporally dynamic ecosystems to more stable systems dominated by homogenous physical habitat. Restoration of desert river systems could aid in biodiversity conservation, but poses formidable challenges due to multiple threats and the infeasibility of recovery to pre-development conditions. The challenges faced in restoring desert rivers can be addressed by incorporating scientific recommendations into restoration planning efforts at multiple stages, as demonstrated here through an example restoration project. In particular, use of a watershed-scale planning process can identify data gaps and irreversible constraints, which aid in developing achievable restoration goals and objectives. Site-prioritization focuses limited the resources for restoration on areas with the greatest potential to improve populations of target organisms. Investment in research to understand causes of degradation, coupled with adoption of a guiding vision is critical for identifying feasible restoration actions that can enhance river processes. Setting monitoring as a project goal, developing hypotheses for expected outcomes, and implementing restoration as an experimental design will facilitate adaptive management and learning from project implementation. Involvement of scientists and managers during all planning stages is critical for developing process-based restoration actions and an implementation plan to maximize learning. The planning process developed here provides a roadmap for use of scientific recommendations in future efforts to recover dynamic processes in imperiled riverine ecosystems.

Application of Science-Based Restoration Planning to a Desert River System

NASA Astrophysics Data System (ADS)

Laub, Brian G.; Jimenez, Justin; Budy, Phaedra

2015-06-01

Persistence of many desert river species is threatened by a suite of impacts linked to water infrastructure projects that provide human water security where water is scarce. Many desert rivers have undergone regime shifts from spatially and temporally dynamic ecosystems to more stable systems dominated by homogenous physical habitat. Restoration of desert river systems could aid in biodiversity conservation, but poses formidable challenges due to multiple threats and the infeasibility of recovery to pre-development conditions. The challenges faced in restoring desert rivers can be addressed by incorporating scientific recommendations into restoration planning efforts at multiple stages, as demonstrated here through an example restoration project. In particular, use of a watershed-scale planning process can identify data gaps and irreversible constraints, which aid in developing achievable restoration goals and objectives. Site-prioritization focuses limited the resources for restoration on areas with the greatest potential to improve populations of target organisms. Investment in research to understand causes of degradation, coupled with adoption of a guiding vision is critical for identifying feasible restoration actions that can enhance river processes. Setting monitoring as a project goal, developing hypotheses for expected outcomes, and implementing restoration as an experimental design will facilitate adaptive management and learning from project implementation. Involvement of scientists and managers during all planning stages is critical for developing process-based restoration actions and an implementation plan to maximize learning. The planning process developed here provides a roadmap for use of scientific recommendations in future efforts to recover dynamic processes in imperiled riverine ecosystems.

Application of science-based restoration planning to a desert river system

USGS Publications Warehouse

Laub, Brian G.; Jimenez, Justin; Budy, Phaedra

2015-01-01

Persistence of many desert river species is threatened by a suite of impacts linked to water infrastructure projects that provide human water security where water is scarce. Many desert rivers have undergone regime shifts from spatially and temporally dynamic ecosystems to more stable systems dominated by homogenous physical habitat. Restoration of desert river systems could aid in biodiversity conservation, but poses formidable challenges due to multiple threats and the infeasibility of recovery to pre-development conditions. The challenges faced in restoring desert rivers can be addressed by incorporating scientific recommendations into restoration planning efforts at multiple stages, as demonstrated here through an example restoration project. In particular, use of a watershed-scale planning process can identify data gaps and irreversible constraints, which aid in developing achievable restoration goals and objectives. Site-prioritization focuses limited the resources for restoration on areas with the greatest potential to improve populations of target organisms. Investment in research to understand causes of degradation, coupled with adoption of a guiding vision is critical for identifying feasible restoration actions that can enhance river processes. Setting monitoring as a project goal, developing hypotheses for expected outcomes, and implementing restoration as an experimental design will facilitate adaptive management and learning from project implementation. Involvement of scientists and managers during all planning stages is critical for developing process-based restoration actions and an implementation plan to maximize learning. The planning process developed here provides a roadmap for use of scientific recommendations in future efforts to recover dynamic processes in imperiled riverine ecosystems.

Architecture-Centric Development in Globally Distributed Projects

NASA Astrophysics Data System (ADS)

Sauer, Joachim

In this chapter architecture-centric development is proposed as a means to strengthen the cohesion of distributed teams and to tackle challenges due to geographical and temporal distances and the clash of different cultures. A shared software architecture serves as blueprint for all activities in the development process and ties them together. Architecture-centric development thus provides a plan for task allocation, facilitates the cooperation of globally distributed developers, and enables continuous integration reaching across distributed teams. Advice is also provided for software architects who work with distributed teams in an agile manner.

Lignin carbon fiber: The path for quality

DOE PAGES

Yuan, Joshua S.; Li, Qiang; Ragauskas, Arthur J.

2017-03-01

Lignin represents an abundant biopolymer and a major waste from lignocellulosic processing plants, yet the utilization of lignin for fungible products remains one of the most challenging technical barriers for pulp mills and the modern biorefinery industry. In recent decades, lignin has been sought after as a precursor polymer for carbon fiber due to the high carbon content (up to 60%). Furthermore lignin carbon fiber is expected to be compatible with the market size of the pulp and paper industry and may have transformative impact on petroleum-based carbon fiber.

PREHAB vs. REHAB - presurgical treatment in vestibular schwannoma surgery enhances recovery of postural control better than postoperative rehabilitation: Retrospective case series.

PubMed

Tjernström, Fredrik; Fransson, Per-Anders; Kahlon, Babar; Karlberg, Mikael; Lindberg, Sven; Siesjö, Peter; Magnusson, Måns

2018-01-01

To evaluate post-surgical postural stability when treating patients with remaining vestibular function with intratympanic gentamicin (PREHAB) prior to schwannoma surgery. 44 consecutive patients with some form remaining vestibular function scheduled for vestibular schwannoma surgery. 20 were medically deafferented with intratympanic gentamicin before surgery and 24 were not. Both groups were of the same age, had the same tumor size, same type of surgery, and same perioperative sensory rehabilitation (training exercises), and no surgical complications. Postural stability measured as energy expenditure while standing on a force platform during vibratory stimulation of the calf muscles, performed prior to surgery (or gentamicin treatment) and 6 months after surgery. Patients pretreated with gentamicin had significantly better postural stability at the time for follow-up (p < 0.05) and displayed a better adaptive capacity when faced with a postural challenge (p < 0.01). They were also able to use vision more efficiently to control their stability (p < 0.05). By separating the sensory loss (through intratympanic gentamicin, that ablates the remaining vestibular function) from the intracranial surgical trauma, the postural control system benefited from a better short-term (adaptation) and long-term (habituation) recovery, when experiencing a postural challenge or resolving a sensory conflict. The benefits could be attributed to; active and continuous motor learning as the vestibular function slowly attenuates; no concomitant central nervous dysfunction due to effects from neurosurgery, thus allowing time for a separate unimpeded recovery process with more limited challenges and objectives; and the initiation and certain progression of sensory reweighting processes allowed prior to surgery. In contrast, worse compensation could be due to; immobilization from nausea after surgery, harmful amount of stress and cognitive dysfunction from the combination of surgical and sensory trauma and an abrupt vestibular deafferentation and its consequences on sensory reweighting.

Reconstruction of structure and function in tissue engineering of solid organs: Toward simulation of natural development based on decellularization.

PubMed

Zheng, Chen-Xi; Sui, Bing-Dong; Hu, Cheng-Hu; Qiu, Xin-Yu; Zhao, Pan; Jin, Yan

2018-04-27

Failure of solid organs, such as the heart, liver, and kidney, remains a major cause of the world's mortality due to critical shortage of donor organs. Tissue engineering, which uses elements including cells, scaffolds, and growth factors to fabricate functional organs in vitro, is a promising strategy to mitigate the scarcity of transplantable organs. Within recent years, different construction strategies that guide the combination of tissue engineering elements have been applied in solid organ tissue engineering and have achieved much progress. Most attractively, construction strategy based on whole-organ decellularization has become a popular and promising approach, because the overall structure of extracellular matrix can be well preserved. However, despite the preservation of whole structure, the current constructs derived from decellularization-based strategy still perform partial functions of solid organs, due to several challenges, including preservation of functional extracellular matrix structure, implementation of functional recellularization, formation of functional vascular network, and realization of long-term functional integration. This review overviews the status quo of solid organ tissue engineering, including both advances and challenges. We have also put forward a few techniques with potential to solve the challenges, mainly focusing on decellularization-based construction strategy. We propose that the primary concept for constructing tissue-engineered solid organs is fabricating functional organs based on intact structure via simulating the natural development and regeneration processes. Copyright © 2018 John Wiley & Sons, Ltd.

Cognitive control in media multitaskers

PubMed Central

Ophir, Eyal; Nass, Clifford; Wagner, Anthony D.

2009-01-01

Chronic media multitasking is quickly becoming ubiquitous, although processing multiple incoming streams of information is considered a challenge for human cognition. A series of experiments addressed whether there are systematic differences in information processing styles between chronically heavy and light media multitaskers. A trait media multitasking index was developed to identify groups of heavy and light media multitaskers. These two groups were then compared along established cognitive control dimensions. Results showed that heavy media multitaskers are more susceptible to interference from irrelevant environmental stimuli and from irrelevant representations in memory. This led to the surprising result that heavy media multitaskers performed worse on a test of task-switching ability, likely due to reduced ability to filter out interference from the irrelevant task set. These results demonstrate that media multitasking, a rapidly growing societal trend, is associated with a distinct approach to fundamental information processing. PMID:19706386

The Dawn of Lead‐Free Perovskite Solar Cell: Highly Stable Double Perovskite Cs2AgBiBr6 Film

PubMed Central

Wu, Cuncun; Zhang, Qiaohui; Liu, Yang; Luo, Wei; Guo, Xuan; Huang, Ziru; Ting, Hungkit; Sun, Weihai; Zhong, Xinrui; Wei, Shiyuan

2017-01-01

Abstract Recently, lead‐free double perovskites have emerged as a promising environmentally friendly photovoltaic material for their intrinsic thermodynamic stability, appropriate bandgaps, small carrier effective masses, and low exciton binding energies. However, currently no solar cell based on these double perovskites has been reported, due to the challenge in film processing. Herein, a first lead‐free double perovskite planar heterojunction solar cell with a high quality Cs2AgBiBr6 film, fabricated by low‐pressure assisted solution processing under ambient conditions, is reported. The device presents a best power conversion efficiency of 1.44%. The preliminary efficiency and the high stability under ambient condition without encapsulation, together with the high film quality with simple processing, demonstrate promise for lead‐free perovskite solar cells. PMID:29593974

Behaviors of printed circuit boards due to microwave supported curing process of coating materials.

PubMed

Bremerkamp, Felix; Nowottnick, Mathias; Seehase, Dirk; Bui, Trinh Dung

2012-01-01

The Application of a microwave supported curing process for coatings in the field of electronic industry poses a challenge. Here the implementation of this technology is represented. Within the scope of the investigation special PCB Test Layouts were designed and the polymer curing process examined by the method of dielectric analysis. Furthermore the coupling of microwave radiation with conductive PCB structures was analyzed experimentally by means of special test boards. The formation of standing waves and regular heating distribution along the conductive wires on the PCB could be observed. The experimental results were compared with numerical simulation. In this context the numerical analysis of microwave PCB interaction led to important findings concerning wave propagation on wired PCB. The final valuation demonstrated a substantial similarity between numerical simulations and experimental results.

Study of hole characteristics in Laser Trepan Drilling of ZTA

NASA Astrophysics Data System (ADS)

Saini, Surendra K.; Dubey, Avanish K.; Upadhyay, B. N.; Choubey, A.

2018-07-01

Zirconia Toughened Alumina ceramic is widely used for aerospace components, combustion chambers, heat exchangers, bearings and pumps mainly due to its improved mechanical and thermal properties. To make holes in thick section Zirconia Toughened Alumina ceramics is a major challenge due to its unfavorable machining characteristics. Recent researches have explored that laser machining can overcome the machining limitations of advanced materials having improved mechanical properties. In present research, authors have analyzed the effect of Laser Trepan Drilling on hole characteristics of 6.0 mm thick Zirconia Toughened Alumina. Effect of significant process parameters on hole characteristics such as hole circularity at top and bottom, hole taper, and spatter size have been studied. The optimum ranges of these parameters have been suggested on the basis of empirical modeling and optimization.

Towards a Cloud Computing Environment: Near Real-time Cloud Product Processing and Distribution for Next Generation Satellites

NASA Astrophysics Data System (ADS)

Nguyen, L.; Chee, T.; Minnis, P.; Palikonda, R.; Smith, W. L., Jr.; Spangenberg, D.

2016-12-01

The NASA LaRC Satellite ClOud and Radiative Property retrieval System (SatCORPS) processes and derives near real-time (NRT) global cloud products from operational geostationary satellite imager datasets. These products are being used in NRT to improve forecast model, aircraft icing warnings, and support aircraft field campaigns. Next generation satellites, such as the Japanese Himawari-8 and the upcoming NOAA GOES-R, present challenges for NRT data processing and product dissemination due to the increase in temporal and spatial resolution. The volume of data is expected to increase to approximately 10 folds. This increase in data volume will require additional IT resources to keep up with the processing demands to satisfy NRT requirements. In addition, these resources are not readily available due to cost and other technical limitations. To anticipate and meet these computing resource requirements, we have employed a hybrid cloud computing environment to augment the generation of SatCORPS products. This paper will describe the workflow to ingest, process, and distribute SatCORPS products and the technologies used. Lessons learn from working on both AWS Clouds and GovCloud will be discussed: benefits, similarities, and differences that could impact decision to use cloud computing and storage. A detail cost analysis will be presented. In addition, future cloud utilization, parallelization, and architecture layout will be discussed for GOES-R.

Challenges and opportunities in the design and construction of a GIS-based emission inventory infrastructure for the Niger Delta region of Nigeria.

PubMed

Fagbeja, Mofoluso A; Hill, Jennifer L; Chatterton, Tim J; Longhurst, James W S; Akpokodje, Joseph E; Agbaje, Ganiy I; Halilu, Shaba A

2017-03-01

Environmental monitoring in middle- and low-income countries is hampered by many factors which include enactment and enforcement of legislations; deficiencies in environmental data reporting and documentation; inconsistent, incomplete and unverifiable data; a lack of access to data; and technical expertise. This paper describes the processes undertaken and the major challenges encountered in the construction of the first Niger Delta Emission Inventory (NDEI) for criteria air pollutants and CO 2 released from the anthropogenic activities in the region. This study focused on using publicly available government and research data. The NDEI has been designed to provide a Geographic Information System-based component of an air quality and carbon management framework. The NDEI infrastructure was designed and constructed at 1-, 10- and 20-km grid resolutions for point, line and area sources using industry standard processes and emission factors derived from activities similar to those in the Niger Delta. Due to inadequate, incomplete, potentially inaccurate and unavailable data, the infrastructure was populated with data based on a series of best possible assumptions for key emission sources. This produces outputs with variable levels of certainty, which also highlights the critical challenges in the estimation of emissions from a developing country. However, the infrastructure is functional and has the ability to produce spatially resolved emission estimates.

Integration and interpretation of InSAR deformation products from the Sentinel-1 constellation - experiences from the InSARap project

NASA Astrophysics Data System (ADS)

Dehls, John F.; Larsen, Yngvar; Marinkovic, Petar; Perski, Zbigniew

2017-04-01

The Sentinel-1 mission has been in operational mode for more than two years, and with the successful commissioning of S1B in Sep 2016, the constellation is now complete. While the InSAR community initially faced many processing challenges due to the introduction of the new TOPS mode, these issues can by now considered resolved. However, truly operational workflows are still to be designed and deployed, and there are a number of integration and interpretation challenges that need to be addressed to achieve operational processing of 6-day revisit InSAR data. In this contribution, we will focus mainly on the integration and interpretation of InSAR products in scientific workflows, rather than on algorithmic details. We will motivate discussion with results obtained from selected pilot sites within the ESA SEOM InSARap project. The sites cover a large part of the application domain for InSAR - "from decimeter to millimeter". Specifically, landslide and corner reflector validation test sites in Norway and Poland will be discussed. The results will serve as basis for a discussion on how to communicate and streamline a portfolio of subsidence products to end users, which is a challenge in itself. We will conclude with a discussion on remaining open questions regarding how we as a community can address these issues to a wider audience.

Light assisted drying (LAD) for protein stabilization: optical characterization of samples

NASA Astrophysics Data System (ADS)

Young, Madison A.; McKinnon, Madison E.; Elliott, Gloria D.; Trammell, Susan R.

2018-02-01

Light-Assisted Drying (LAD) is a novel biopreservation technique which allows proteins to be immobilized in a dry, amorphous solid at room temperature. Indicator proteins are used in a variety of diagnostic assays ranging from highthroughput 96-well plates to new microfluidic devices. A challenge in the development of protein-based assays is preserving the structure of the protein during production and storage of the assay, as the structure of the protein is responsible for its functional activity. Freeze-drying or freezing are currently the standard for the preservation of proteins, but these methods are expensive and can be challenging in some environments due to a lack of available infrastructure. An inexpensive, simple processing method that enables supra-zero temperature storage of proteins used in assays is needed. Light-assisted drying offers a relatively inexpensive method for drying samples. Proteins suspended in a trehalose solution are dehydrated using near-infrared laser light. The laser radiation speeds drying and as water is removed the sugar forms a protective matrix. The goal of this study is optically characterize samples processed with LAD. We use polarized light imaging (PLI) to look at crystallization kinetics of samples and determine optimal humidity. PLI shows a 62.5% chance of crystallization during LAD processing and negligible crystallization during low RH storage.

The Lisbon new international airport: The story of a decision-making process and the role of Strategic Environmental Assessment

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

Partidario, Maria R., E-mail: mrp@civil.ist.utl.p; Coutinho, Miguel, E-mail: miguel.coutinho@ua.p

2011-04-15

This is the brief story of a decision process and the role of Strategic Environmental Assessment in government political decision-making. Following a prolonged, and agitated, decision process, initiated in the 1960s, the Government of Portugal in 2005 took the final decision to build the new international airport of Lisbon at the controversial location of Ota, 40 km north of Lisbon. The detailed project design and EIA were started. However this decision would change in 2007 due to the challenge raised by a private sponsored study that identified an alternative location for the airport at Campo de Tiro de Alcochete (CTA).more » This new site, which had never been considered as an option before, appeared to avoid many of the problems that caused public controversy at the Ota site. The Government, pressured by this challenge, promoted a strategic comparative assessment between the two sites. The result of this study was the choice of CTA as the preferred location. This paper discusses this radical change in the decision from a socio-political perspective. It will highlight the relevance of Strategic Environmental Assessment (SEA), and the strategic and constructive approach it enables in mega-project decision-making.« less

Public relations and the radiation processing industry

NASA Astrophysics Data System (ADS)

Coates, T. Donna

The world's uneasiness and mistrust regarding anything nuclear has heightened in recent years due to events such as Chernobyl and Three Mile Island. Opinion polls and attitude surveys document the public's growing concern about issues such as the depletion of the ozone layer, the resulting greenhouse effect and exposure of our planet to cosmic radiation. Ultimately, such research reveals an underlying fear regarding the unseen impacts of modern technology on the environment and on human health. These concerns have obvious implications for the radiation processing industry, whose technology is nuclear based and not easily understood by the public. We have already seen organized nuclear opponents mobilize public anxiety, fear and misunderstanding in order to oppose the installation of radiation processing facilities and applications such as food irradiation. These opponents will no doubt try to strengthen resistance to our technology in the future. Opponents will attempt to convince the public that the risks to public and personal health and safety outweigh the benefits of our technology. We in the industry must head off any tendency for the public to see us as the "enemy". Our challenge is to counter public uneasiness and misunderstanding by effectively communicating the human benefits of our technology. Clearly it is a challenge we cannot afford to ignore.

Decision analysis and drug development portfolio management: uncovering the real options value of your projects.

PubMed

Rosati, Nicoletta

2002-04-01

Project selection and portfolio management are particularly challenging in the pharmaceutical industry due to the high risk - high stake nature of the drug development process. In the recent years, scholars and industry experts have agreed that traditional Net-Present-Value evaluation of the projects fails to capture the value of managerial flexibility, and encouraged adopting a real options approach to recover the missed value. In this paper, we take a closer look at the drug development process and at the indices currently used to rank projects. We discuss the economic value of information and of real options arising in drug development and present decision analysis as an ideal framework for the implementation of real options valuation.

Progress towards CSR RL06 GRACE gravity solutions

NASA Astrophysics Data System (ADS)

Save, Himanshu

2017-04-01

The GRACE project plans to re-processes the GRACE mission data in order to be consistent with the first gravity products released by the GRACE-FO project. The next generation Release-06 (RL06) gravity products from GRACE will include the improvements in GRACE Level-1 data products, background gravity models and the processing methodology. This paper will outline the planned improvements for CSR - RL06 and discuss the preliminary results. This paper will discuss the evolution of the quality of the GRACE solutions, especially over the past few years. We will also discuss the possible challenges we may face in connecting/extending the measurements of mass fluxes from the GRACE era to the GRACE-FO era due quality of the GRACE solutions from recent years.

Verification of Triple Modular Redundancy (TMR) Insertion for Reliable and Trusted Systems

NASA Technical Reports Server (NTRS)

Berg, Melanie; LaBel, Kenneth A.

2016-01-01

We propose a method for TMR insertion verification that satisfies the process for reliable and trusted systems. If a system is expected to be protected using TMR, improper insertion can jeopardize the reliability and security of the system. Due to the complexity of the verification process, there are currently no available techniques that can provide complete and reliable confirmation of TMR insertion. This manuscript addresses the challenge of confirming that TMR has been inserted without corruption of functionality and with correct application of the expected TMR topology. The proposed verification method combines the usage of existing formal analysis tools with a novel search-detect-and-verify tool. Field programmable gate array (FPGA),Triple Modular Redundancy (TMR),Verification, Trust, Reliability,

Building a print on demand web service

NASA Astrophysics Data System (ADS)

Reddy, Prakash; Rozario, Benedict; Dudekula, Shariff; V, Anil Dev

2011-03-01

There is considerable effort underway to digitize all books that have ever been printed. There is need for a service that can take raw book scans and convert them into Print on Demand (POD) books. Such a service definitely augments the digitization effort and enables broader access to a wider audience. To make this service practical we have identified three key challenges that needed to be addressed. These are: a) produce high quality image images by eliminating artifacts that exist due to the age of the document or those that are introduced during the scanning process b) develop an efficient automated system to process book scans with minimum human intervention; and c) build an eco system which allows us the target audience to discover these books.

Virtual Observation System for Earth System Model: An Application to ACME Land Model Simulations

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

Wang, Dali; Yuan, Fengming; Hernandez, Benjamin

Investigating and evaluating physical-chemical-biological processes within an Earth system model (EMS) can be very challenging due to the complexity of both model design and software implementation. A virtual observation system (VOS) is presented to enable interactive observation of these processes during system simulation. Based on advance computing technologies, such as compiler-based software analysis, automatic code instrumentation, and high-performance data transport, the VOS provides run-time observation capability, in-situ data analytics for Earth system model simulation, model behavior adjustment opportunities through simulation steering. A VOS for a terrestrial land model simulation within the Accelerated Climate Modeling for Energy model is also presentedmore » to demonstrate the implementation details and system innovations.« less

Usage of machine learning for the separation of electroweak and strong Zγ production at the LHC experiments

NASA Astrophysics Data System (ADS)

Petukhov, A. M.; Soldatov, E. Yu

2017-12-01

Separation of electroweak component from strong component of associated Zγ production on hadron colliders is a very challenging task due to identical final states of such processes. The only difference is the origin of two leading jets in these two processes. Rectangular cuts on jet kinematic variables from ATLAS/CMS 8 TeV Zγ experimental analyses were improved using machine learning techniques. New selection variables were also tested. The expected significance of separation for LHC experiments conditions at the second datataking period (Run2) and 120 fb-1 amount of data reaches more than 5σ. Future experimental observation of electroweak Zγ production can also lead to the observation physics beyond Standard Model.

Virtual Observation System for Earth System Model: An Application to ACME Land Model Simulations

DOE PAGES

Wang, Dali; Yuan, Fengming; Hernandez, Benjamin; ...

2017-01-01

Investigating and evaluating physical-chemical-biological processes within an Earth system model (EMS) can be very challenging due to the complexity of both model design and software implementation. A virtual observation system (VOS) is presented to enable interactive observation of these processes during system simulation. Based on advance computing technologies, such as compiler-based software analysis, automatic code instrumentation, and high-performance data transport, the VOS provides run-time observation capability, in-situ data analytics for Earth system model simulation, model behavior adjustment opportunities through simulation steering. A VOS for a terrestrial land model simulation within the Accelerated Climate Modeling for Energy model is also presentedmore » to demonstrate the implementation details and system innovations.« less

Search for $WZ/ZZ$ Production in the Lepton(s) + MET + Jets Channel with the CDF Experiment at the Tevatron Collider

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

Trovato, Marco

2014-01-01

In this thesis we present a search for the WZ and ZZ production in a final state ("W+2 jets") with a leptonically-decaying W and two energetic jets. We use the full dataset ( ∫ Ldt = 8:9 fb -1) recorded with the CDF detector at Fermilab. The challenge consists in extracting the small Z-hadronic peak from the large amount of background processes. Those processes also include the WW, whose hadronic peak cannot be distinguished from the Z peak, due to the poor calorimeter resolution. In the past such a signature was used to measure the diboson cross section, which ismore » highly dominated by the WW cross section.« less

Perampanel and Challenging Behaviour in Intellectual Disability and Epilepsy: A Management Dilemma

PubMed Central

Choudry, Ansar

2014-01-01

We describe a case of a patient with a diagnosis of moderate learning disability with challenging behaviour and treatment refractory epilepsy. Antiepileptics can increase challenging behaviour; however, antipsychotics can provoke seizures. This results in a difficult balance for patient care. Due to worsening seizures, the patient was prescribed perampanel. This increased her aggression and agitation resulting in admission. We trialled four antipsychotic drugs to reduce her challenging behaviour, two of which worsened her seizures. It was necessary to continue antiepileptic medication to maintain adequate seizure control. However, the resulting uncontrolled challenging behaviour persisted, meaning she was unable to return to her family home on discharge. This case emphasises the difficult scenario clinician's encounter when balancing the use of antipsychotics and antiepileptics. The case demonstrates the significant functional loss due to challenging behaviour, balanced against controlling life threatening seizures. PMID:25580340

Visualization of DNA in highly processed botanical materials.

PubMed

Lu, Zhengfei; Rubinsky, Maria; Babajanian, Silva; Zhang, Yanjun; Chang, Peter; Swanson, Gary

2018-04-15

DNA-based methods have been gaining recognition as a tool for botanical authentication in herbal medicine; however, their application in processed botanical materials is challenging due to the low quality and quantity of DNA left after extensive manufacturing processes. The low amount of DNA recovered from processed materials, especially extracts, is "invisible" by current technology, which has casted doubt on the presence of amplifiable botanical DNA. A method using adapter-ligation and PCR amplification was successfully applied to visualize the "invisible" DNA in botanical extracts. The size of the "invisible" DNA fragments in botanical extracts was around 20-220 bp compared to fragments of around 600 bp for the more easily visualized DNA in botanical powders. This technique is the first to allow characterization and visualization of small fragments of DNA in processed botanical materials and will provide key information to guide the development of appropriate DNA-based botanical authentication methods in the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Novel Method for Making Biomedical Segregation-Free Ti-30Ta Alloy Spherical Powder for Additive Manufacturing

NASA Astrophysics Data System (ADS)

Xia, Yang; Fang, Zhigang Zak; Sun, Pei; Zhang, Ying; Zhu, Jun

2018-03-01

Ti-Ta alloys offer a good combination of high strength and low modulus among Ti-based alloys, and are ideal for biomedical applications. However, making Ti-Ta alloys has always been challenging because they tend to suffer from compositional segregation during melting due to the large difference between the melting points of Ti and Ta. This article describes a novel process for making spherical Ti-30Ta alloy powder through a unique powder metallurgy technique, namely the granulation-sintering-deoxygenation process. The results indicate that the compositional segregation problem can be overcome using this process technology. Combined with use of a deoxygenation process, the critical interstitial element, oxygen, can be controlled to < 400 ppm for powder with particle size < 75 µm. The destabilization effect of Ta on Ti-O solid solutions, and the resulting improved deoxygenation process for Ti-Ta, are discussed, as well as the phase composition and microstructure of the powders.

Experimental investigation of springback in air bending process

NASA Astrophysics Data System (ADS)

Alhammadi, Aysha; Rafique, Hafsa; Alkaabi, Meera; Abu Qudeiri, Jaber

2018-03-01

Bending processes is one of the important processes in sheet metal forming. One of the challenge that faces the air bending process is springback, which happens due to the elastic recovery during unloading stage. An accurate analysis of springback during the bending process is crucial to achieve a required bend angle. This paper will investigate the springback experimentally by changing many parameters such as tested material, die opening, thickness, etc. and finding its effect on the value of springback. Additionally, the paper will investigate the effect of loading time at the end of loading stage on the springback by proposing a multistage bending technique (MBT). In MBT, the loading will stop during loading stage just before the end of this stage and it will restart again shortly after. In this study, three sheet metals with different thickness will be examined, namely stainless steel, aluminium and brass. Artificial neural network (ANN) will be utilized to develop a prediction model to predict springback based on the experimental results.

Spinal cord grey matter segmentation challenge.

PubMed

Prados, Ferran; Ashburner, John; Blaiotta, Claudia; Brosch, Tom; Carballido-Gamio, Julio; Cardoso, Manuel Jorge; Conrad, Benjamin N; Datta, Esha; Dávid, Gergely; Leener, Benjamin De; Dupont, Sara M; Freund, Patrick; Wheeler-Kingshott, Claudia A M Gandini; Grussu, Francesco; Henry, Roland; Landman, Bennett A; Ljungberg, Emil; Lyttle, Bailey; Ourselin, Sebastien; Papinutto, Nico; Saporito, Salvatore; Schlaeger, Regina; Smith, Seth A; Summers, Paul; Tam, Roger; Yiannakas, Marios C; Zhu, Alyssa; Cohen-Adad, Julien

2017-05-15

An important image processing step in spinal cord magnetic resonance imaging is the ability to reliably and accurately segment grey and white matter for tissue specific analysis. There are several semi- or fully-automated segmentation methods for cervical cord cross-sectional area measurement with an excellent performance close or equal to the manual segmentation. However, grey matter segmentation is still challenging due to small cross-sectional size and shape, and active research is being conducted by several groups around the world in this field. Therefore a grey matter spinal cord segmentation challenge was organised to test different capabilities of various methods using the same multi-centre and multi-vendor dataset acquired with distinct 3D gradient-echo sequences. This challenge aimed to characterize the state-of-the-art in the field as well as identifying new opportunities for future improvements. Six different spinal cord grey matter segmentation methods developed independently by various research groups across the world and their performance were compared to manual segmentation outcomes, the present gold-standard. All algorithms provided good overall results for detecting the grey matter butterfly, albeit with variable performance in certain quality-of-segmentation metrics. The data have been made publicly available and the challenge web site remains open to new submissions. No modifications were introduced to any of the presented methods as a result of this challenge for the purposes of this publication. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Quantitative and qualitative processes of change during staff-coaching sessions: an exploratory study.

PubMed

van Oorsouw, Wietske M W J; Embregts, Petri J C M; Bosman, Anna M T

2013-05-01

Staff training is one of the interventions that managers can embed in their organizations to help staff improve their professional competences related to challenging behaviour of clients with intellectual disabilities. Individual coaching adds learning opportunities that are feasible but difficult to achieve in an in-service setting. In the present study, we have followed the coaching process of three staff members. Based on differences in the Linell balance of power across sessions, we explored the question: do different coaching processes have similar patterns in the development of dominance and coherence in interactions between coach and staff? Additionally, a qualitative approach was conducted to illustrate and enrich the meaning of quantitative outcomes. Processes were different regarding the balance of power at the start of the coaching, probably due to differences in resistance and insecurity. As a consequence of different starting points and differences in learning styles, each coaching process had its unique development over time. At the end, all dyads were comparable in the sense that all dyads were highly satisfied about the outcomes and process of coaching. This is in line with similar levels of power at the end of the coaching sessions suggesting equal contributions and leadership. The present findings suggest some relevant competencies of coaches within health-care services. Due to the small number of participants, the results have to be interpreted with caution. The present study provides suggestions for future research and clinical practice. Copyright © 2013 Elsevier Ltd. All rights reserved.

Methodological strategies in using home sleep apnea testing in research and practice.

PubMed

Miller, Jennifer N; Schulz, Paula; Pozehl, Bunny; Fiedler, Douglas; Fial, Alissa; Berger, Ann M

2017-11-14

Home sleep apnea testing (HSAT) has increased due to improvements in technology, accessibility, and changes in third party reimbursement requirements. Research studies using HSAT have not consistently reported procedures and methodological challenges. This paper had two objectives: (1) summarize the literature on use of HSAT in research of adults and (2) identify methodological strategies to use in research and practice to standardize HSAT procedures and information. Search strategy included studies of participants undergoing sleep testing for OSA using HSAT. MEDLINE via PubMed, CINAHL, and Embase with the following search terms: "polysomnography," "home," "level III," "obstructive sleep apnea," and "out of center testing." Research articles that met inclusion criteria (n = 34) inconsistently reported methods and methodological challenges in terms of: (a) participant sampling; (b) instrumentation issues; (c) clinical variables; (d) data processing; and (e) patient acceptability. Ten methodological strategies were identified for adoption when using HSAT in research and practice. Future studies need to address the methodological challenges summarized in this paper as well as identify and report consistent HSAT procedures and information.

Informed consent in psychiatry clinical research: A conceptual review of issues, challenges, and recommendations

PubMed Central

Gupta, Umesh Chandra; Kharawala, Saifuddin

2012-01-01

Obtaining informed consent in psychiatry clinical research involving subjects with diminished mental abilities and impaired consent capacity has been a challenge for researchers, posing many ethical concerns and procedural hurdles due to participants’ cognitive deficits and impaired ability to judge reality. Regulations seem inadequate and provide limited guidance, not sufficient to address all the ethical issues inherent in different situations related to obtaining consent from decisionally impaired persons. Researchers are struggling to find a balance between risk-benefit ratio, research advancement, and autonomy of study subjects. Inspired to improve the consent process in psychiatry clinical research, many studies have been conducted focusing on various informed consent-related ethical concerns, with the aim of developing appropriate strategies and optimizing the informed consent procedure in psychiatry clinical research, overcoming the ethical concerns. This article critically reviews the various ethical issues and consent challenges, their underlying reasons, and investigates the appropriate strategies and practices needed to be adopted while obtaining informed consent from subjects with impaired consent capacity, participating in psychiatry clinical research. PMID:22347696

Eliminating Iodine Deficiency in China: Achievements, Challenges and Global Implications

PubMed Central

Sun, Dianjun; Codling, Karen; Chang, Suying; Zhang, Shubin; Shen, Hongmei; Su, Xiaohui; Chen, Zupei; Scherpbier, Robert W.; Yan, Jun

2017-01-01

The prevention of iodine deficiency through salt iodization has been recognized as a global success story, and China stands at the forefront of this achievement with one of the most successful programs in the world. High level political commitment, national mandatory legislation, a state-managed edible salt industry and a complex and highly sophisticated surveillance system have facilitated the success of the program. Challenges have arisen however, including: (i) concern that adequate iodine status in pregnant women cannot be achieved without causing above adequate iodine intakes in children; (ii) declining iodine intake as a result of reductions in salt consumption and increased consumption of processed foods, which may not be made with iodized salt; (iii) the existence of areas with high iodine content in the water; and (iv) declines in household use of iodized salt due to concerns about excess iodine intake and thyroid disease. This article reviews the achievements and challenges of the Chinese Iodine Deficiency Disorders (IDD) Elimination Program and reflects on lessons learned and implications for other national salt iodization programs. PMID:28379180

Risk of Performance Decrement and Crew Illness Due to an Inadequate Food System

NASA Technical Reports Server (NTRS)

Douglas, Grace L.; Cooper, Maya; Bermudez-Aguirre, Daniela; Sirmons, Takiyah

2016-01-01

NASA is preparing for long duration manned missions beyond low-Earth orbit that will be challenged in several ways, including long-term exposure to the space environment, impacts to crew physiological and psychological health, limited resources, and no resupply. The food system is one of the most significant daily factors that can be altered to improve human health, and performance during space exploration. Therefore, the paramount importance of determining the methods, technologies, and requirements to provide a safe, nutritious, and acceptable food system that promotes crew health and performance cannot be underestimated. The processed and prepackaged food system is the main source of nutrition to the crew, therefore significant losses in nutrition, either through degradation of nutrients during processing and storage or inadequate food intake due to low acceptability, variety, or usability, may significantly compromise the crew's health and performance. Shelf life studies indicate that key nutrients and quality factors in many space foods degrade to concerning levels within three years, suggesting that food system will not meet the nutrition and acceptability requirements of a long duration mission beyond low-Earth orbit. Likewise, mass and volume evaluations indicate that the current food system is a significant resource burden. Alternative provisioning strategies, such as inclusion of bioregenerative foods, are challenged with resource requirements, and food safety and scarcity concerns. Ensuring provisioning of an adequate food system relies not only upon determining technologies, and requirements for nutrition, quality, and safety, but upon establishing a food system that will support nutritional adequacy, even with individual crew preference and self-selection. In short, the space food system is challenged to maintain safety, nutrition, and acceptability for all phases of an exploration mission within resource constraints. This document presents the evidence for the Risk of Performance Decrement and Crew Illness Due to an Inadequate Food System and the gaps in relation to exploration, as identified by the NASA Human Research Program (HRP). The research reviewed here indicates strategies to establish methods, technologies, and requirements that increase food stability, support adequate nutrition, quality, and variety, enable supplementation with grow-pick-and-eat salad crops, ensure safety, and reduce resource use. Obtaining the evidence to establish an adequate food system is essential, as the resources allocated to the food system may be defined based on the data relating nutritional stability and food quality requirements to crew performance and health.

Composite wastewater treatment by aerated electrocoagulation and modified peroxi-coagulation processes.

PubMed

Kumar, Abhijeet; Nidheesh, P V; Suresh Kumar, M

2018-08-01

Treatment of composite wastewater generating from the industrial estates is a great challenge. The present study examines the applicability of aerated electrocoagulation and modified peroxi-coagulation processes for removing color and COD from composite wastewater. Iron plates were used as anodes and cathodes in both electrochemical processes and experiments were carried out in a working volume of 2 L. Aeration enhanced the efficiency of electrocoagulation process significantly. More than 50% of COD and 60% of color were removed after 1 h of electrocoagulation process operated at pH 3 and applied voltage of 1 V. Efficiency of the modified peroxi-coagulation process was significantly higher than that of aerated electrocoagulation. COD and color removal efficiencies of the modified peroxi-coagulation process were found as 77.7% and 97%, respectively after 1 h of electrolysis operated at 1 V, solution pH 3 and 50 mM hydrogen peroxide addition. This improved efficiency of modified peroxi-coagulation compared to aerated electrocoagulation is mainly due to the attack of in-situ generated hydroxyl radicals. Copyright © 2018 Elsevier Ltd. All rights reserved.

Kinect Posture Reconstruction Based on a Local Mixture of Gaussian Process Models.

PubMed

Liu, Zhiguang; Zhou, Liuyang; Leung, Howard; Shum, Hubert P H

2016-11-01

Depth sensor based 3D human motion estimation hardware such as Kinect has made interactive applications more popular recently. However, it is still challenging to accurately recognize postures from a single depth camera due to the inherently noisy data derived from depth images and self-occluding action performed by the user. In this paper, we propose a new real-time probabilistic framework to enhance the accuracy of live captured postures that belong to one of the action classes in the database. We adopt the Gaussian Process model as a prior to leverage the position data obtained from Kinect and marker-based motion capture system. We also incorporate a temporal consistency term into the optimization framework to constrain the velocity variations between successive frames. To ensure that the reconstructed posture resembles the accurate parts of the observed posture, we embed a set of joint reliability measurements into the optimization framework. A major drawback of Gaussian Process is its cubic learning complexity when dealing with a large database due to the inverse of a covariance matrix. To solve the problem, we propose a new method based on a local mixture of Gaussian Processes, in which Gaussian Processes are defined in local regions of the state space. Due to the significantly decreased sample size in each local Gaussian Process, the learning time is greatly reduced. At the same time, the prediction speed is enhanced as the weighted mean prediction for a given sample is determined by the nearby local models only. Our system also allows incrementally updating a specific local Gaussian Process in real time, which enhances the likelihood of adapting to run-time postures that are different from those in the database. Experimental results demonstrate that our system can generate high quality postures even under severe self-occlusion situations, which is beneficial for real-time applications such as motion-based gaming and sport training.

Investigation of electromigration behavior in lead-free flip chip solder bumps

NASA Astrophysics Data System (ADS)

Kalkundri, Kaustubh Jayant

Packaging technology has also evolved over time in an effort to keep pace with the demanding requirements. Wirebond and flip chip packaging technologies have become extremely versatile and ubiquitous in catering to myriad applications due to their inherent potential. This research is restricted strictly to flip chip technology. This technology incorporates a process in which the bare chip is turned upside down, i.e., active face down, and is bonded through the I/O to the substrate, hence called flip chip. A solder interconnect that provides electrical connection between the chip and substrate is bumped on a processed silicon wafer prior to dicing for die-attach. The assembly is then reflow-soldered followed by the underfill process to provide the required encapsulation. The demand for smaller and lighter products has increased the number of I/Os without increasing the package sizes, thereby drastically reducing the size of the flip chip solder bumps and their pitch. Reliability assessment and verification of these devices has gained tremendous importance due to their shrinking size. To add to the complexity, changing material sets that are results of recently enacted lead-free solder legislations have raised some compatibility issues that are already being researched. In addition to materials and process related flip chip challenges such as solder-flux compatibility, Coefficient of Thermal Expansion (CTE) mismatch, underfill-flux compatibility and thermal management, flip chip packages are vulnerable to a comparatively newer challenge, namely electromigration observed in solder bumps. It is interesting to note that electromigration has come to the forefront of challenges only recently. It has been exacerbated by the reduction in bump cross-section due to the seemingly continuous shrinking in package size over time. The focus of this research was to understand the overall electromigration behavior in lead-free (SnAg) flip chip solder bumps. The objectives of the research were to comprehend the physics of failure mechanism in electromigration for lead-free solder bumps assembled in a flip chip ceramic package having thick copper under bump metallization and to estimate the unknown critical material parameters from Black's equation that describe failure due to electromigration. In addition, the intent was to verify the 'use condition reliability' by extrapolation from experimental conditions. The methodology adopted for this research was comprised of accelerated electromigration tests on SnAg flip chip solder bumps assembled on ceramic substrate with a thick copper under bump metallization. The experimental approach was comprised of elaborate measurement of the temperature of each sample by separate metallization resistance exhibiting positive resistance characteristics to overcome the variation in Joule heating. After conducting the constant current experiments and analyzing the failed samples, it was found that the primary electromigration failure mode observed was the dissolution of the thick copper under bump metallization in the solder, leading to a change in resistance. The lifetime data obtained from different experiments was solved simultaneously using a multiple regression approach to yield the unknown Black's equation parameters of current density exponent and activation energy. In addition to the implementation of a systematic failure analysis and data analysis procedure, it was also deduced that thermomigration due to the temperature gradient across the chip does impact the overall electromigration behavior. This research and the obtained results were significant in bridging the gap for an overall understanding of this critical failure mode observed in flip chip solder bumps. The measurement of each individual sample temperature instead of an average temperature enabled an accurate analysis for predicting the 'use condition reliability' of a comparable product. The obtained results and the conclusions can be used as potential inputs in future designs and newer generations of flip chip devices that might undergo aggressive scaling. This will enable these devices to retain their functionality during their intended useful life with minimal threat of failure due to the potent issue of electromigration. (Abstract shortened by UMI.)

High index glass thin film processing for photonics and photovoltaic (PV) applications

NASA Astrophysics Data System (ADS)

Ogbuu, Okechukwu Anthony

To favorably compete with fossil-fuel technology, the greatest challenge for thin film solar-cells is to improve efficiency and reduce material cost. Thickness scaling to thin film reduces material cost but affects the light absorption in the cells; therefore a concept that traps incident photons and increases its optical path length is needed to boost absorption in thin film solar cells. One approach is the integration of low symmetric gratings (LSG), using high index material, on either the front-side or backside of 30 um thin c-Si cells. In this study, Multicomponent TeO2--Bi2O 3--ZnO (TBZ) glass thin films were prepared using RF magnetron sputtering under different oxygen flow rates. The influences of oxygen flow rate on the structural and optical properties of the resulting thin films were investigated. The structural origin of the optical property variation was studied using X-ray diffraction, X-ray photoelectron spectroscopy, Raman Spectroscopy, and transmission electron microscopy. The results indicate that TBZ glass thin film is a suitable material for front side LSG material photovoltaic and photonics applications due to their amorphous nature, high refractive index (n > 2), broad band optical transparency window, low processing temperature. We developed a simple maskless method to pattern sputtered tellurite based glass thin films using unconventional agarose hydrogel mediated wet etching. Conventional wet etching process, while claiming low cost and high throughput, suffers from reproducibility and pattern fidelity issues due to the isotropic nature of wet chemical etching when applied to glasses and polymers. This method overcomes these challenges by using an agarose hydrogel stamp to mediate a conformal etching process. In our maskless method, agarose hydrogel stamps are patterned following a standard soft lithography and replica molding process from micropatterned masters and soaked in a chemical etchant. The micro-scale features on the stamp are subsequently transferred into glass and polymer thin films via conformal wet etching. High refractive index chalcogenide glass (n = 2.6) thin films with composition As20Se80 was selected for backside LSG material due to their attractive properties. We developed an optimized integration protocol for LSG integration and successfully integrated these LSG structures at the back side of both 30 microm c-Si solar cells and standalone 30 microm c-Si wafers. Optical and electrical characterization of LSG on thin c-Si cells shows that LSG structures create higher absorption enhancement and external quantum efficiency at long wavelengths.

Image segmentation using joint spatial-intensity-shape features: application to CT lung nodule segmentation

NASA Astrophysics Data System (ADS)

Ye, Xujiong; Siddique, Musib; Douiri, Abdel; Beddoe, Gareth; Slabaugh, Greg

2009-02-01

Automatic segmentation of medical images is a challenging problem due to the complexity and variability of human anatomy, poor contrast of the object being segmented, and noise resulting from the image acquisition process. This paper presents a novel feature-guided method for the segmentation of 3D medical lesions. The proposed algorithm combines 1) a volumetric shape feature (shape index) based on high-order partial derivatives; 2) mean shift clustering in a joint spatial-intensity-shape (JSIS) feature space; and 3) a modified expectation-maximization (MEM) algorithm on the mean shift mode map to merge the neighboring regions (modes). In such a scenario, the volumetric shape feature is integrated into the process of the segmentation algorithm. The joint spatial-intensity-shape features provide rich information for the segmentation of the anatomic structures or lesions (tumors). The proposed method has been evaluated on a clinical dataset of thoracic CT scans that contains 68 nodules. A volume overlap ratio between each segmented nodule and the ground truth annotation is calculated. Using the proposed method, the mean overlap ratio over all the nodules is 0.80. On visual inspection and using a quantitative evaluation, the experimental results demonstrate the potential of the proposed method. It can properly segment a variety of nodules including juxta-vascular and juxta-pleural nodules, which are challenging for conventional methods due to the high similarity of intensities between the nodules and their adjacent tissues. This approach could also be applied to lesion segmentation in other anatomies, such as polyps in the colon.

SWCD: a sliding window and self-regulated learning-based background updating method for change detection in videos

NASA Astrophysics Data System (ADS)

Işık, Şahin; Özkan, Kemal; Günal, Serkan; Gerek, Ömer Nezih

2018-03-01

Change detection with background subtraction process remains to be an unresolved issue and attracts research interest due to challenges encountered on static and dynamic scenes. The key challenge is about how to update dynamically changing backgrounds from frames with an adaptive and self-regulated feedback mechanism. In order to achieve this, we present an effective change detection algorithm for pixelwise changes. A sliding window approach combined with dynamic control of update parameters is introduced for updating background frames, which we called sliding window-based change detection. Comprehensive experiments on related test videos show that the integrated algorithm yields good objective and subjective performance by overcoming illumination variations, camera jitters, and intermittent object motions. It is argued that the obtained method makes a fair alternative in most types of foreground extraction scenarios; unlike case-specific methods, which normally fail for their nonconsidered scenarios.

Design of a rear anamorphic attachment for digital cinematography

NASA Astrophysics Data System (ADS)

Cifuentes, A.; Valles, A.

2008-09-01

Digital taking systems for HDTV and now for the film industry present a particularly challenging design problem for rear adapters in general. The thick 3-channel prism block in the camera provides an important challenge in the design. In this paper the design of a 1.33x rear anamorphic attachment is presented. The new design departs significantly from the traditional Bravais condition due to the thick dichroic prism block. Design strategies for non-rotationally symmetric systems and fields of view are discussed. Anamorphic images intrinsically have a lower contrast and less resolution than their rotationally symmetric counterparts, therefore proper image evaluation must be considered. The interpretation of the traditional image quality methods applied to anamorphic images is also discussed in relation to the design process. The final design has a total track less than 50 mm, maintaining the telecentricity of the digital prime lens and taking full advantage of the f/1.4 prism block.

Access to Fresh Fruits and Vegetables in School Lunches: A Policy Analysis.

PubMed

Schultz, Celeste; Thorlton, Janet

2018-01-01

Consumption of fresh fruits and vegetables helps to reduce childhood obesity and improves academic achievement and attendance. However, providing fresh fruits and vegetables is challenging for some schools due to cost, administrative burden, and concern for food waste. To address these challenges, the Fruit and Vegetable Access for Children Act proposes to allow federally funded programs to substitute fresh fruits and vegetables with canned, frozen, or pureed versions. In this policy analysis, we propose options for providing fresh fruits and vegetables to children enrolled in the National School Lunch Program. We recommend that school nurses actively facilitate the process of obtaining fresh fruits and vegetables by being appointed members of Team Nutrition giving them authority to collaborate with local famers, entrepreneurs, and land-grant universities in Farm to School Programs. This strategy empowers school nurses in promoting healthy eating habits, reducing obesity, and improving academic performance and school attendance.

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.

Reference Materials: Significance, General Requirements, and Demand.

PubMed

Kiełbasa, Anna; Gadzała-Kopciuch, Renata; Buszewski, Bogusław

2016-05-03

Reference materials play an important part in the quality control of measurements. Rapid development of such new scientific disciplines as proteomics, metabolomics, and genomics also necessitates development of new reference materials. This is a great challenge due to the complexity of the production of new reference materials and difficulties associated with achieving their homogeneity and stability. CRMs of tissue are of particular importance. They can be counted among the matrices that are most complex and time consuming in preparation. Tissue is the place of transformation and accumulation of many substances (e.g., metabolites, which are intermediate or end products resulting from metabolic processes). Trace amounts of many substances in tissues must be determined with adequate precision and accuracy. To meet the needs stemming from research and from problems and challenges faced by chemists, analysts, and toxicologists, the number of certified reference materials should be continuously increased.

Functional imaging and the cerebellum: recent developments and challenges. Editorial.

PubMed

Habas, Christophe

2012-06-01

Recent neuroimaging developments allow a better in vivo characterization of the structural and functional connectivity of the human cerebellum. Ultrahigh fields, which considerably increase spatial resolution, enable to visualize deep cerebellar nuclei and cerebello-cortical sublayers. Tractography reconstructs afferent and efferent pathway of the cerebellum. Resting-state functional connectivity individualizes the prewired, parallel close-looped sensorimotor, cognitive, and affective networks passing through the cerebellum. These results are un agreement with activation maps obtained during stimulation functional neuroimaging or inferred from neurological deficits due to cerebellar lesions. Therefore, neuroimaging supports the hypothesis that cerebellum constitutes a general modulator involved in optimizing mental performance and computing internal models. However, the great challenges will remain to unravel: (1) the functional role of red and bulbar olivary nuclei, (2) the information processing in the cerebellar microcircuitry, and (3) the abstract computation performed by the cerebellum and shared by sensorimotor, cognitive, and affective domains.

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

Cheng, Shiwang; Xie, Shi-Jie; Carrillo, Jan-Michael Y.

Polymer nanocomposites (PNCs) are important materials that are widely used in many current technologies and potentially have broader applications in the future due to their excellent property of tunability, light weight and low cost. But, expanding the limits in property enhancement remains a fundamental scientific challenge. We demonstrate that well-dispersed, small (diameter ~1.8 nm) nanoparticles with attractive interactions lead to unexpectedly large and qualitatively new changes in PNC structural dynamics in comparison to conventional composites based on particles of diameter ~10-50 nm. At the same time, the zero-shear viscosity at high temperatures remains comparable to that of the neat polymer,more » thereby retaining good processibility and resolving a major challenge in PNC applications. These results suggest that the nanoparticle mobility and relatively short lifetimes of nanoparticlepolymer associations open qualitatively new horizons in tunability of macroscopic properties in nanocomposites with high potential for the development of new functional materials.« less

New challenges in solar energy resource and forecasting in Greece

NASA Astrophysics Data System (ADS)

Kazantzidis, A.; Nikitidou, E.; Salamalikis, V.; Tzoumanikas, P.; Zagouras, A.

2018-05-01

Aerosols and clouds are the most important constituents in the atmosphere that affect the incoming solar radiation, either directly through absorbing and scattering processes or indirectly by changing the optical properties and lifetime of clouds. Under clear skies, aerosols become the dominant factor that affect the intensity of solar irradiance reaching the ground. Under cloudy skies, the high temporal and spatial variability of cloudiness is the key factor for the estimation of solar irradiance. In this study, recent research activities related to the climatology and the prediction of solar energy in Greece are presented with emphasis on new challenges in the climatology of global horizontal irradiance (GHI) and direct normal irradiance (DNI), the changes of DNI due to the decreasing aerosol optical depth and the short-term (15-240 min) forecasts of solar irradiance with the collaborative use of neural networks and satellite images.

Signal Processing for Metagenomics: Extracting Information from the Soup

PubMed Central

Rosen, Gail L.; Sokhansanj, Bahrad A.; Polikar, Robi; Bruns, Mary Ann; Russell, Jacob; Garbarine, Elaine; Essinger, Steve; Yok, Non

2009-01-01

Traditionally, studies in microbial genomics have focused on single-genomes from cultured species, thereby limiting their focus to the small percentage of species that can be cultured outside their natural environment. Fortunately, recent advances in high-throughput sequencing and computational analyses have ushered in the new field of metagenomics, which aims to decode the genomes of microbes from natural communities without the need for cultivation. Although metagenomic studies have shed a great deal of insight into bacterial diversity and coding capacity, several computational challenges remain due to the massive size and complexity of metagenomic sequence data. Current tools and techniques are reviewed in this paper which address challenges in 1) genomic fragment annotation, 2) phylogenetic reconstruction, 3) functional classification of samples, and 4) interpreting complementary metaproteomics and metametabolomics data. Also surveyed are important applications of metagenomic studies, including microbial forensics and the roles of microbial communities in shaping human health and soil ecology. PMID:20436876

Atmospheric turbulence compensation in orbital angular momentum communications: Advances and perspectives

NASA Astrophysics Data System (ADS)

Li, Shuhui; Chen, Shi; Gao, Chunqing; Willner, Alan E.; Wang, Jian

2018-02-01

Orbital angular momentum (OAM)-carrying beams have recently generated considerable interest due to their potential use in communication systems to increase transmission capacity and spectral efficiency. For OAM-based free-space optical (FSO) links, a critical challenge is the atmospheric turbulence that will distort the helical wavefronts of OAM beams leading to the decrease of received power, introducing crosstalk between multiple channels, and impairing link performance. In this paper, we review recent advances in turbulence effects compensation techniques for OAM-based FSO communication links. First, basic concepts of atmospheric turbulence and theoretical model are introduced. Second, atmospheric turbulence effects on OAM beams are theoretically and experimentally investigated and discussed. Then, several typical turbulence compensation approaches, including both adaptive optics-based (optical domain) and signal processing-based (electrical domain) techniques, are presented. Finally, key challenges and perspectives of compensation of turbulence-distorted OAM links are discussed.

Monitoring Quality of Biotherapeutic Products Using Multivariate Data Analysis.

PubMed

Rathore, Anurag S; Pathak, Mili; Jain, Renu; Jadaun, Gaurav Pratap Singh

2016-07-01

Monitoring the quality of pharmaceutical products is a global challenge, heightened by the implications of letting subquality drugs come to the market on public safety. Regulatory agencies do their due diligence at the time of approval as per their prescribed regulations. However, product quality needs to be monitored post-approval as well to ensure patient safety throughout the product life cycle. This is particularly complicated for biotechnology-based therapeutics where seemingly minor changes in process and/or raw material attributes have been shown to have a significant effect on clinical safety and efficacy of the product. This article provides a perspective on the topic of monitoring the quality of biotech therapeutics. In the backdrop of challenges faced by the regulatory agencies, the potential use of multivariate data analysis as a tool for effective monitoring has been proposed. Case studies using data from several insulin biosimilars have been used to illustrate the key concepts.

Facing technological challenges of Solar Updraft Power Plants

NASA Astrophysics Data System (ADS)

Lupi, F.; Borri, C.; Harte, R.; Krätzig, W. B.; Niemann, H.-J.

2015-01-01

The Solar Updraft Power Plant technology addresses a very challenging idea of combining two kinds of renewable energy: wind and solar. The working principle is simple: a Solar Updraft Power Plant (SUPP) consists of a collector area to heat the air due to the wide-banded ultra-violet solar radiation, the high-rise solar tower to updraft the heated air to the atmosphere, and in between the power conversion unit, where a system of coupled turbines and generators transforms the stream of heated air into electric power. A good efficiency of the power plant can only be reached with extra-large dimensions of the tower and/or the collector area. The paper presents an up-to-date review of the SUPP technology, focusing on the multi-physics modeling of the power plant, on the structural behavior of the tower and, last but not least, on the modeling of the stochastic wind loading process.

Enantioselective cyclizations and cyclization cascades of samarium ketyl radicals

NASA Astrophysics Data System (ADS)

Kern, Nicolas; Plesniak, Mateusz P.; McDouall, Joseph J. W.; Procter, David J.

2017-12-01

The rapid generation of molecular complexity from simple starting materials is a key challenge in synthesis. Enantioselective radical cyclization cascades have the potential to deliver complex, densely packed, polycyclic architectures, with control of three-dimensional shape, in one step. Unfortunately, carrying out reactions with radicals in an enantiocontrolled fashion remains challenging due to their high reactivity. This is particularly the case for reactions of radicals generated using the classical reagent, SmI2. Here, we demonstrate that enantioselective SmI2-mediated radical cyclizations and cascades that exploit a simple, recyclable chiral ligand can convert symmetrical ketoesters to complex carbocyclic products bearing multiple stereocentres with high enantio- and diastereocontrol. A computational study has been used to probe the origin of the enantioselectivity. Our studies suggest that many processes that rely on SmI2 can be rendered enantioselective by the design of suitable ligands.

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.

Geological mapping goes 3-D in response to societal needs

USGS Publications Warehouse

Thorleifson, H.; Berg, R.C.; Russell, H.A.J.

2010-01-01

The transition to 3-D mapping has been made possible by technological advances in digital cartography, GIS, data storage, analysis, and visualization. Despite various challenges, technological advancements facilitated a gradual transition from 2-D maps to 2.5-D draped maps to 3-D geological mapping, supported by digital spatial and relational databases that can be interrogated horizontally or vertically and viewed interactively. Challenges associated with data collection, human resources, and information management are daunting due to their resource and training requirements. The exchange of strategies at the workshops has highlighted the use of basin analysis to develop a process-based predictive knowledge framework that facilitates data integration. Three-dimensional geological information meets a public demand that fills in the blanks left by conventional 2-D mapping. Two-dimensional mapping will, however, remain the standard method for extensive areas of complex geology, particularly where deformed igneous and metamorphic rocks defy attempts at 3-D depiction.

Self-Biased Hybrid Piezoelectric-Photoelectrochemical Cell with Photocatalytic Functionalities.

PubMed

Tan, Chuan Fu; Ong, Wei Li; Ho, Ghim Wei

2015-07-28

Utilizing solar energy for environmental and energy remediations based on photocatalytic hydrogen (H2) generation and water cleaning poses great challenges due to inadequate visible-light power conversion, high recombination rate, and intermittent availability of solar energy. Here, we report an energy-harvesting technology that utilizes multiple energy sources for development of sustainable operation of dual photocatalytic reactions. The fabricated hybrid cell combines energy harvesting from light and vibration to run a power-free photocatalytic process that exploits novel metal-semiconductor branched heterostructure (BHS) of its visible light absorption, high charge-separation efficiency, and piezoelectric properties to overcome the aforementioned challenges. The desirable characteristics of conductive flexible piezoelectrode in conjunction with pronounced light scattering of hierarchical structure originate intrinsically from the elaborate design yet facile synthesis of BHS. This self-powered photocatalysis system could potentially be used as H2 generator and water treatment system to produce clean energy and water resources.

Faculty Experiences of Merger and Organizational Change in a Social Work Program.

PubMed

Adedoyin, A Christson; Miller, Monte; Jackson, Mary S; Dodor, Bernice; Hall, Kristen

2016-01-01

Social work programs are experiencing unprecedented organizational changes due to budget cuts, dwindling resources, global, and technological challenges. However, there is limited information in the literature about the merger experiences of faculty in social work programs. On one hand undergoing merger and reorganization provides the opportunity to reorganize, reprioritize, re-assess, develop strategies, and explore previously untapped opportunities for social work programs. Conversely, merger experiences have caused frustration, intention to quit, confusion, and loss of professional identity for social work faculty. In this article the authors utilize a journaling method and sense-making approach of the merger experiences of some of the faculty members of a social work program in the United States. The authors suggest a framework to understand how the faculty confronted the challenges, overcame the pitfalls, and maximized the opportunities offered during the merger and organizational change process.

Wireless Multimedia Sensor Networks: Current Trends and Future Directions

PubMed Central

Almalkawi, Islam T.; Zapata, Manel Guerrero; Al-Karaki, Jamal N.; Morillo-Pozo, Julian

2010-01-01

Wireless Multimedia Sensor Networks (WMSNs) have emerged and shifted the focus from the typical scalar wireless sensor networks to networks with multimedia devices that are capable to retrieve video, audio, images, as well as scalar sensor data. WMSNs are able to deliver multimedia content due to the availability of inexpensive CMOS cameras and microphones coupled with the significant progress in distributed signal processing and multimedia source coding techniques. In this paper, we outline the design challenges of WMSNs, give a comprehensive discussion of the proposed architectures, algorithms and protocols for the different layers of the communication protocol stack for WMSNs, and evaluate the existing WMSN hardware and testbeds. The paper will give the reader a clear view of the state of the art at all aspects of this research area, and shed the light on its main current challenges and future trends. We also hope it will foster discussions and new research ideas among its researchers. PMID:22163571

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

The Challenges of Field Testing the Traffic Management Advisor (TMA) in an Operational Air Traffic Control Facility

NASA Technical Reports Server (NTRS)

Hoang, Ty; Swenson, Harry N.

1997-01-01

The Traffic Management Advisor (TMA), the sequence and schedule tool of the Center/TRACON Automation System (CTAS), was evaluated at the Fort Worth Center (ZFW) in the summer of 1996. This paper describes the challenges encountered during the various phases of the TMA field evaluation, which included system (hardware and software) installation, personnel training, and data collection. Operational procedures were developed and applied to the evaluation process that would ensure air safety. The five weeks of field evaluation imposed minimal impact on the hosting facility and provided valuable engineering and human factors data. The collection of data was very much an opportunistic affair, due to dynamic traffic conditions. One measure of the success of the TMA evaluation is that, rather than remove TMA after the evaluation until it could be fully implemented, the prototype TMA is in continual use at ZFW as the fully operational version is readied for implementation.

Agmatine rescues autistic behaviors in the valproic acid-induced animal model of autism.

PubMed

Kim, Ji-Woon; Seung, Hana; Kim, Ki Chan; Gonzales, Edson Luck T; Oh, Hyun Ah; Yang, Sung Min; Ko, Mee Jung; Han, Seol-Heui; Banerjee, Sourav; Shin, Chan Young

2017-02-01

Autism spectrum disorder (ASD) is an immensely challenging developmental disorder characterized primarily by two core behavioral symptoms of social communication deficits and restricted/repetitive behaviors. Investigating the etiological process and identifying an appropriate therapeutic target remain as formidable challenges to overcome ASD due to numerous risk factors and complex symptoms associated with the disorder. Among the various mechanisms that contribute to ASD, the maintenance of excitation and inhibition balance emerged as a key factor to regulate proper functioning of neuronal circuitry. Interestingly, our previous study involving the valproic acid animal model of autism (VPA animal model) has demonstrated excitatory-inhibitory imbalance (E/I imbalance) due to enhanced differentiation of glutamatergic neurons and reduced GABAergic neurons. Here, we investigated the potential of agmatine, an endogenous NMDA receptor antagonist, as a novel therapeutic candidate in ameliorating ASD symptoms by modulating E/I imbalance using the VPA animal model. We observed that a single treatment of agmatine rescued the impaired social behaviors as well as hyperactive and repetitive behaviors in the VPA animal model. We also observed that agmatine treatment rescued the overly activated ERK1/2 signaling in the prefrontal cortex and hippocampus of VPA animal models, possibly, by modulating over-excitability due to enhanced excitatory neural circuit. Taken together, our results have provided experimental evidence suggesting a possible therapeutic role of agmatine in ameliorating ASD-like symptoms in the VPA animal model of ASD. Copyright © 2016 Elsevier Ltd. All rights reserved.

NASA Institute for Advanced Concepts

NASA Technical Reports Server (NTRS)

Cassanova, Robert A.

1999-01-01

The purpose of NASA Institute for Advanced Concepts (NIAC) is to provide an independent, open forum for the external analysis and definition of space and aeronautics advanced concepts to complement the advanced concepts activities conducted within the NASA Enterprises. The NIAC will issue Calls for Proposals during each year of operation and will select revolutionary advanced concepts for grant or contract awards through a peer review process. Final selection of awards will be with the concurrence of NASA's Chief Technologist. The operation of the NIAC is reviewed biannually by the NIAC Science, Exploration and Technology Council (NSETC) whose members are drawn from the senior levels of industry and universities. The process of defining the technical scope of the initial Call for Proposals was begun with the NIAC "Grand Challenges" workshop conducted on May 21-22, 1998 in Columbia, Maryland. These "Grand Challenges" resulting from this workshop became the essence of the technical scope for the first Phase I Call for Proposals which was released on June 19, 1998 with a due date of July 31, 1998. The first Phase I Call for Proposals attracted 119 proposals. After a thorough peer review, prioritization by NIAC and technical concurrence by NASA, sixteen subgrants were awarded. The second Phase I Call for Proposals was released on November 23, 1998 with a due date of January 31, 1999. Sixty-three (63) proposals were received in response to this Call. On December 2-3, 1998, the NSETC met to review the progress and future plans of the NIAC. The next NSETC meeting is scheduled for August 5-6, 1999. The first Phase II Call for Proposals was released to the current Phase I grantees on February 3,1999 with a due date of May 31, 1999. Plans for the second year of the contract include a continuation of the sequence of Phase I and Phase II Calls for Proposals and hosting the first NIAC Annual Meeting and USRA/NIAC Technical Symposium in NASA HQ.

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.

Developing synthesis techniques for zeolitic-imidazolate framework membranes for high resolution propylene/propane separation

NASA Astrophysics Data System (ADS)

Kwon, Hyuk Taek

Propylene/propane separation is one of the most challenging separations, currently achieved by energy-intensive cryogenic distillation. Despite the great potentials for energy-efficient membrane-based propylene/propane separation processes, no commercial membranes are available due to the limitations (i.e., low selectivity) of current polymeric materials. Zeolitic imidazolate frameworks (ZIFs) are promising membrane materials primarily due to their well-defined ultra-micropores with controllable surface chemistry along with their relatively high thermal/chemical stabilities. In particular, ZIF-8 with the effective aperture size of ~ 4.0 A has been shown very promising for propylene/propane separation. Despite the extensive research on ZIF-8 membranes, only a few of ZIF-8 membranes have displayed good propylene/propane separation performances presumably due to the challenges of controlling the microstructures of polycrystalline membranes. Since the membrane microstructures are greatly influenced by processing techniques, it is critically important to develop new techniques. In this dissertation, three state-of-the-art ZIF membrane synthesis techniques are developed. The first is a one-step in-situ synthesis technique based on the concept of counter diffusion. The technique enabled us to obtain highly propylene selective ZIF-8 membranes in less than a couple of hours with exceptional mechanical strength. Most importantly, due to the nature of the counter-diffusion concept, the new method offered unique opportunities such as healing defective membranes (i.e., poorly-intergrown) as well as significantly reducing the consumption of costly ligands and organic solvents. The second is a microwave-assisted seeding technique. Using this new seeding technique, we were able to prepare seeded supports with a high packing density in a couple of minutes, which subsequently grown into highly propylene-selective ZIF-8 membranes with an average propylene/propane selectivity of ~40. The last is a heteroepitaxial growth technique. The first well-intergrown membranes of ZIF-67 (Co-substituted ZIF-8) by heteroepitaxially growing ZIF-67 on ZIF-8 seed layers were reported. The ZIF-67 membranes exhibited impressively high propylene/propane separation capabilities. The presence of a methanol co-solvent in the growth solution was critically important to reproducibly prepare high quality ZIF-67 membranes. Furthermore, when the tertiary growth of ZIF-8 layers was applied to the ZIF-67 membranes, the membranes exhibited unprecedentedly high propylene/propane separation factors of ~ 200 possibly due to enhanced grain boundary structure.

Towards real-time remote processing of laparoscopic video

NASA Astrophysics Data System (ADS)

Ronaghi, Zahra; Duffy, Edward B.; Kwartowitz, David M.

2015-03-01

Laparoscopic surgery is a minimally invasive surgical technique where surgeons insert a small video camera into the patient's body to visualize internal organs and small tools to perform surgical procedures. However, the benefit of small incisions has a drawback of limited visualization of subsurface tissues, which can lead to navigational challenges in the delivering of therapy. Image-guided surgery (IGS) uses images to map subsurface structures and can reduce the limitations of laparoscopic surgery. One particular laparoscopic camera system of interest is the vision system of the daVinci-Si robotic surgical system (Intuitive Surgical, Sunnyvale, CA, USA). The video streams generate approximately 360 megabytes of data per second, demonstrating a trend towards increased data sizes in medicine, primarily due to higher-resolution video cameras and imaging equipment. Processing this data on a bedside PC has become challenging and a high-performance computing (HPC) environment may not always be available at the point of care. To process this data on remote HPC clusters at the typical 30 frames per second (fps) rate, it is required that each 11.9 MB video frame be processed by a server and returned within 1/30th of a second. The ability to acquire, process and visualize data in real-time is essential for performance of complex tasks as well as minimizing risk to the patient. As a result, utilizing high-speed networks to access computing clusters will lead to real-time medical image processing and improve surgical experiences by providing real-time augmented laparoscopic data. We aim to develop a medical video processing system using an OpenFlow software defined network that is capable of connecting to multiple remote medical facilities and HPC servers.

Thyrotropinoma and multinodular goiter: A diagnostic challenge for hyperthyroidism.

PubMed

Aksoy, Duygu Yazgan; Gedik, Arzu; Cinar, Nese; Soylemezoglu, Figen; Berker, Mustafa; Gurlek, Omer Alper

2013-11-01

Thyroid disorders are frequently encountered. The diagnosis is straightforward unless clinical or laboratory findings are inconclusive and/or perplexing. Hyperthyroidism due to a thyrotropin-secreting pituitary adenoma rarely occurs and symptoms due to thyroid hormone excess are subtle. The presentation of the disease becomes unusual when co-secretion of other hormones with thyrotropin or concomitant thyroid parenchymal pathology exist. We present the case of a 63-year-old female patient with thyrotropinoma co-secreting growth hormone and multinodular goiter. She developed hyperthyroidism first due to thyrotropinoma and later due to a toxic nodule. Herein, we discuss the diagnostic and therapeutic challenges of hyperthyroidism with atypical presentation.

Modeling solvent evaporation during thin film formation in phase separating polymer mixtures

DOE PAGES

Cummings, John; Lowengrub, John S.; Sumpter, Bobby G.; ...

2018-02-09

Preparation of thin films by dissolving polymers in a common solvent followed by evaporation of the solvent has become a routine processing procedure. However, modeling of thin film formation in an evaporating solvent has been challenging due to a need to simulate processes at multiple length and time scales. In this paper, we present a methodology based on the principles of linear non-equilibrium thermodynamics, which allows systematic study of various effects such as the changes in the solvent properties due to phase transformation from liquid to vapor and polymer thermodynamics resulting from such solvent transformations. The methodology allows for themore » derivation of evaporative flux and boundary conditions near each surface for simulations of systems close to the equilibrium. We apply it to study thin film microstructural evolution in phase segregating polymer blends dissolved in a common volatile solvent and deposited on a planar substrate. Finally, effects of the evaporation rates, interactions of the polymers with the underlying substrate and concentration dependent mobilities on the kinetics of thin film formation are studied.« less

Modeling solvent evaporation during thin film formation in phase separating polymer mixtures

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

Cummings, John; Lowengrub, John S.; Sumpter, Bobby G.

Preparation of thin films by dissolving polymers in a common solvent followed by evaporation of the solvent has become a routine processing procedure. However, modeling of thin film formation in an evaporating solvent has been challenging due to a need to simulate processes at multiple length and time scales. In this paper, we present a methodology based on the principles of linear non-equilibrium thermodynamics, which allows systematic study of various effects such as the changes in the solvent properties due to phase transformation from liquid to vapor and polymer thermodynamics resulting from such solvent transformations. The methodology allows for themore » derivation of evaporative flux and boundary conditions near each surface for simulations of systems close to the equilibrium. We apply it to study thin film microstructural evolution in phase segregating polymer blends dissolved in a common volatile solvent and deposited on a planar substrate. Finally, effects of the evaporation rates, interactions of the polymers with the underlying substrate and concentration dependent mobilities on the kinetics of thin film formation are studied.« less

Maskless Lithography and in situ Visualization of Conductivity of Graphene using Helium Ion Microscopy

DOE PAGES

Iberi, Vighter O.; Vlassiouk, Ivan V.; Zhang, X. -G.; ...

2015-07-07

The remarkable mechanical and electronic properties of graphene make it an ideal candidate for next generation nanoelectronics. With the recent development of commercial-level single-crystal graphene layers, the potential for manufacturing household graphene-based devices has improved, but significant challenges still remain with regards to patterning the graphene into devices. In the case of graphene supported on a substrate, traditional nanofabrication techniques such as e-beam lithography (EBL) are often used in fabricating graphene nanoribbons but the multi-step processes they require can result in contamination of the graphene with resists and solvents. In this letter, we report the utility of scanning helium ionmore » lithography for fabricating functional graphene nanoconductors that are supported directly on a silicon dioxide layer, and we measure the minimum feature size achievable due to limitations imposed by thermal fluctuations and ion scattering during the milling process. Further we demonstrate that ion beams, due to their positive charging nature, may be used to observe and test the conductivity of graphene-based nanoelectronic devices in situ.« less

Super-formable pure magnesium at room temperature.

PubMed

Zeng, Zhuoran; Nie, Jian-Feng; Xu, Shi-Wei; H J Davies, Chris; Birbilis, Nick

2017-10-17

Magnesium, the lightest structural metal, is difficult to form at room temperature due to an insufficient number of deformation modes imposed by its hexagonal structure and a strong texture developed during thermomechanical processes. Although appropriate alloying additions can weaken the texture, formability improvement is limited because alloying additions do not fundamentally alter deformation modes. Here we show that magnesium can become super-formable at room temperature without alloying. Despite possessing a strong texture, magnesium can be cold rolled to a strain at least eight times that possible in conventional processing. The resultant cold-rolled sheet can be further formed without cracking due to grain size reduction to the order of one micron and inter-granular mechanisms becoming dominant, rather than the usual slip and twinning. These findings provide a pathway for developing highly formable products from magnesium and other hexagonal metals that are traditionally difficult to form at room temperature.Replacing steel or aluminium vehicle parts with magnesium would result in reduced emissions, but shaping magnesium without cracking remains challenging. Here, the authors successfully extrude and roll textured magnesium into ductile foil at low temperatures by activating intra-granular mechanisms.

Physico-Chemical Alternatives in Lignocellulosic Materials in Relation to the Kind of Component for Fermenting Purposes

PubMed Central

Coz, Alberto; Llano, Tamara; Cifrián, Eva; Viguri, Javier; Maican, Edmond; Sixta, Herbert

2016-01-01

The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulosic-based biorefinery. However, due to the structure of the lignocellulosic materials, and depending basically on the main parameters within the pretreatment steps, numerous byproducts are generated and they act as inhibitors in the fermentation operations. In this sense, the impact of inhibitory compounds derived from lignocellulosic materials is one of the major challenges for a sustainable biomass-to-biofuel and -bioproduct industry. In order to minimise the negative effects of these compounds, numerous methodologies have been tested including physical, chemical, and biological processes. The main physical and chemical treatments have been studied in this work in relation to the lignocellulosic material and the inhibitor in order to point out the best mechanisms for fermenting purposes. In addition, special attention has been made in the case of lignocellulosic hydrolysates obtained by chemical processes with SO2, due to the complex matrix of these materials and the increase in these methodologies in future biorefinery markets. Recommendations of different detoxification methods have been given. PMID:28773700

Gaussian Process modelling of blood glucose response to free-living physical activity data in people with type 1 diabetes.

PubMed

Valletta, John Joseph; Chipperfield, Andrew J; Byrne, Christopher D

2009-01-01

Good blood glucose control is important to people with type 1 diabetes to prevent diabetes-related complications. Too much blood glucose (hyperglycaemia) causes long-term micro-vascular complications, while a severe drop in blood glucose (hypoglycaemia) can cause life-threatening coma. Finding the right balance between quantity and type of food intake, physical activity levels and insulin dosage, is a daily challenge. Increased physical activity levels often cause changes in blood glucose due to increased glucose uptake into tissues such as muscle. To date we have limited knowledge about the minute by minute effects of exercise on blood glucose levels, in part due to the difficulty in measuring glucose and physical activity levels continuously, in a free-living environment. By using a light and user-friendly armband we can record physical activity energy expenditure on a minute-by-minute basis. Simultaneously, by using a continuous glucose monitoring system we can record glucose concentrations. In this paper, Gaussian Processes are used to model the glucose excursions in response to physical activity data, to study its effect on glycaemic control.

ADMultiImg: a novel missing modality transfer learning based CAD system for diagnosis of MCI due to AD using incomplete multi-modality imaging data

NASA Astrophysics Data System (ADS)

Liu, Xiaonan; Chen, Kewei; Wu, Teresa; Weidman, David; Lure, Fleming; Li, Jing

2018-02-01

Alzheimer's Disease (AD) is the most common cause of dementia and currently has no cure. Treatments targeting early stages of AD such as Mild Cognitive Impairment (MCI) may be most effective to deaccelerate AD, thus attracting increasing attention. However, MCI has substantial heterogeneity in that it can be caused by various underlying conditions, not only AD. To detect MCI due to AD, NIA-AA published updated consensus criteria in 2011, in which the use of multi-modality images was highlighted as one of the most promising methods. It is of great interest to develop a CAD system based on automatic, quantitative analysis of multi-modality images and machine learning algorithms to help physicians more adequately diagnose MCI due to AD. The challenge, however, is that multi-modality images are not universally available for many patients due to cost, access, safety, and lack of consent. We developed a novel Missing Modality Transfer Learning (MMTL) algorithm capable of utilizing whatever imaging modalities are available for an MCI patient to diagnose the patient's likelihood of MCI due to AD. Furthermore, we integrated MMTL with radiomics steps including image processing, feature extraction, and feature screening, and a post-processing for uncertainty quantification (UQ), and developed a CAD system called "ADMultiImg" to assist clinical diagnosis of MCI due to AD using multi-modality images together with patient demographic and genetic information. Tested on ADNI date, our system can generate a diagnosis with high accuracy even for patients with only partially available image modalities (AUC=0.94), and therefore may have broad clinical utility.

Innovative and water based stripping approach for thick and bulk photoresists

NASA Astrophysics Data System (ADS)

Rudolph, Matthias; Schumann, Dirk; Thrun, Xaver; Esche, Silvio; Hohle, Christoph

2014-10-01

The usage of phase fluid based stripping agents to remove photoresists from silicon substrates was studied. Photoresists are required for many silicon based technologies such as MEMS patterning, 3D-Integration or frontend and backend of line semiconductor applications [1]. Although the use of resists is very common, their successful integration often depends on the ability to remove the resist after certain processing steps. On the one hand the resist is changing during subsequent process steps that can cause a thermally activated cross-linking which increases the stripping complexity. Resist removal is also challenging after the formation of a hard polymer surface layer during plasma or implant processes which is called skin or crust [2]. On the other hand the choice of stripping chemistry is often limited due to the presence of functional materials such as metals which can be damaged by aggressive stripping chemistries [3].

Decapsulation Method for Flip Chips with Ceramics in Microelectronic Packaging

NASA Astrophysics Data System (ADS)

Shih, T. I.; Duh, J. G.

2008-06-01

The decapsulation of flip chips bonded to ceramic substrates is a challenging task in the packaging industry owing to the vulnerability of the chip surface during the process. In conventional methods, such as manual grinding and polishing, the solder bumps are easily damaged during the removal of underfill, and the thin chip may even be crushed due to mechanical stress. An efficient and reliable decapsulation method consisting of thermal and chemical processes was developed in this study. The surface quality of chips after solder removal is satisfactory for the existing solder rework procedure as well as for die-level failure analysis. The innovative processes included heat-sink and ceramic substrate removal, solder bump separation, and solder residue cleaning from the chip surface. In the last stage, particular temperatures were selected for the removal of eutectic Pb-Sn, high-lead, and lead-free solders considering their respective melting points.

Challenges in Laser Sintering of Thermoset Imide Resin

NASA Technical Reports Server (NTRS)

Chuang, Kathy C.; Gornet, Timothy; Koerner, Hilmar

2016-01-01

Polymer Laser Sintering (LS) is an additive manufacturing technique that builds 3D models layer by layer using a laser to selectively melt cross sections in powdered polymeric materials, following sequential slices of the CAD model. LS generally uses thermoplastic polymeric powders, such as polyamides (i.e. Nylon), and the resultant 3D objects are often weaker in their strength compared to traditionally processed materials, due to the lack of polymer inter-chain connection in the z-direction. The objective of this project is to investigate the possibility of printing a melt-processable RTM370 imide resin powder terminated with reactive phenylethynyl groups by LS, followed by a postcure in order to promote additional crosslinking to achieve higher temperature (250-300 C) capability. A preliminary study to build tensile specimens by LS and the corresponding DSC and rheology study of RTM370 during LS process is presented.

Selective removal of cesium by ammonium molybdophosphate - polyacrylonitrile bead and membrane.

PubMed

Ding, Dahu; Zhang, Zhenya; Chen, Rongzhi; Cai, Tianming

2017-02-15

The selective removal of radionuclides with extremely low concentrations from environmental medium remains a big challenge. Ammonium molybdophosphate possess considerable selectivity towards cesium ion (Cs + ) due to the specific ion exchange between Cs + and NH 4 + . Ammonium molybdophosphate - polyacrylonitrile (AMP-PAN) membrane was successfully prepared for the first time in this study. Efficient removal of Cs + (95.7%, 94.1% and 91.3% of 1mgL -1 ) from solutions with high ionic strength (400mgL -1 of Na + , Ca 2+ or K + ) was achieved by AMP-PAN composite. Multilayer chemical adsorption process was testified through kinetic and isotherm studies. The estimated maximum adsorption capacities even reached 138.9±21.3mgg -1 . Specifically, the liquid film diffusion was identified as the rate-limiting step throughout the removal process. Finally, AMP-PAN membrane could eliminate Cs + from water effectively through the filtration adsorption process. Copyright © 2016 Elsevier B.V. All rights reserved.

Registration of adaptive optics corrected retinal nerve fiber layer (RNFL) images

PubMed Central

Ramaswamy, Gomathy; Lombardo, Marco; Devaney, Nicholas

2014-01-01

Glaucoma is the leading cause of preventable blindness in the western world. Investigation of high-resolution retinal nerve fiber layer (RNFL) images in patients may lead to new indicators of its onset. Adaptive optics (AO) can provide diffraction-limited images of the retina, providing new opportunities for earlier detection of neuroretinal pathologies. However, precise processing is required to correct for three effects in sequences of AO-assisted, flood-illumination images: uneven illumination, residual image motion and image rotation. This processing can be challenging for images of the RNFL due to their low contrast and lack of clearly noticeable features. Here we develop specific processing techniques and show that their application leads to improved image quality on the nerve fiber bundles. This in turn improves the reliability of measures of fiber texture such as the correlation of Gray-Level Co-occurrence Matrix (GLCM). PMID:24940551

Registration of adaptive optics corrected retinal nerve fiber layer (RNFL) images.

PubMed

Ramaswamy, Gomathy; Lombardo, Marco; Devaney, Nicholas

2014-06-01

Glaucoma is the leading cause of preventable blindness in the western world. Investigation of high-resolution retinal nerve fiber layer (RNFL) images in patients may lead to new indicators of its onset. Adaptive optics (AO) can provide diffraction-limited images of the retina, providing new opportunities for earlier detection of neuroretinal pathologies. However, precise processing is required to correct for three effects in sequences of AO-assisted, flood-illumination images: uneven illumination, residual image motion and image rotation. This processing can be challenging for images of the RNFL due to their low contrast and lack of clearly noticeable features. Here we develop specific processing techniques and show that their application leads to improved image quality on the nerve fiber bundles. This in turn improves the reliability of measures of fiber texture such as the correlation of Gray-Level Co-occurrence Matrix (GLCM).

Harmony search optimization in dimensional accuracy of die sinking EDM process using SS316L stainless steel

NASA Astrophysics Data System (ADS)

Deris, A. M.; Zain, A. M.; Sallehuddin, R.; Sharif, S.

2017-09-01

Electric discharge machine (EDM) is one of the widely used nonconventional machining processes for hard and difficult to machine materials. Due to the large number of machining parameters in EDM and its complicated structural, the selection of the optimal solution of machining parameters for obtaining minimum machining performance is remain as a challenging task to the researchers. This paper proposed experimental investigation and optimization of machining parameters for EDM process on stainless steel 316L work piece using Harmony Search (HS) algorithm. The mathematical model was developed based on regression approach with four input parameters which are pulse on time, peak current, servo voltage and servo speed to the output response which is dimensional accuracy (DA). The optimal result of HS approach was compared with regression analysis and it was found HS gave better result y giving the most minimum DA value compared with regression approach.

Thrombocytosis: Diagnostic Evaluation, Thrombotic Risk Stratification, and Risk-Based Management Strategies

PubMed Central

Bleeker, Jonathan S.; Hogan, William J.

2011-01-01

Thrombocytosis is a commonly encountered clinical scenario, with a large proportion of cases discovered incidentally. The differential diagnosis for thrombocytosis is broad and the diagnostic process can be challenging. Thrombocytosis can be spurious, attributed to a reactive process or due to clonal disorder. This distinction is important as it carries implications for evaluation, prognosis, and treatment. Clonal thrombocytosis associated with the myeloproliferative neoplasms, especially essential thrombocythemia and polycythemia vera, carries a unique prognostic profile, with a markedly increased risk of thrombosis. This risk is the driving factor behind treatment strategies in these disorders. Clinical trials utilizing targeted therapies in thrombocytosis are ongoing with new therapeutic targets waiting to be explored. This paper will outline the mechanisms underlying thrombocytosis, the diagnostic evaluation of thrombocytosis, complications of thrombocytosis with a special focus on thrombotic risk as well as treatment options for clonal processes leading to thrombocytosis, including essential thrombocythemia and polycythemia vera. PMID:22084665

A strategy to improve priority setting in developing countries.

PubMed

Kapiriri, Lydia; Martin, Douglas K

2007-09-01

Because the demand for health services outstrips the available resources, priority setting is one of the most difficult issues faced by health policy makers, particularly those in developing countries. Priority setting in developing countries is fraught with uncertainty due to lack of credible information, weak priority setting institutions, and unclear priority setting processes. Efforts to improve priority setting in these contexts have focused on providing information and tools. In this paper we argue that priority setting is a value laden and political process, and although important, the available information and tools are not sufficient to address the priority setting challenges in developing countries. Additional complementary efforts are required. Hence, a strategy to improve priority setting in developing countries should also include: (i) capturing current priority setting practices, (ii) improving the legitimacy and capacity of institutions that set priorities, and (iii) developing fair priority setting processes.

[Cultural dimensions of the childhood primary health care delivery from the mothers' perceptions in the Araucania-Chile].

PubMed

Alarcón-Muñoz, Ana Maria; Vidal-Herrera, Aldo Conrado

2005-01-01

To explore the cultural dimensions of the childhood primary health care delivery process from the mothers' perceptions in the Araucania region of Chile. Qualitative study performed in the year 2003 within the zone with the highest ethnicity rate of the country. Ninety four Mapuche and non-Mapuche mothers agreed to be in depth interviewed. The analysis drew three cultural dimensions: a) Explanatory models of disease were associated with cultural, political-economy, and environmental factors; b) The therapeutic itinerary blends indigenous, popular, and biomedical resources and; c) Health care delivery process lacks of cultural competence. The mothers explain their children diseases articulating religious, magic, and natural (hot, cold, humidity) causes. The main challenge of the primary healthcare delivery process is to overcome the communicational barriers due to the social and linguistic differences between mothers and health care providers.

Open circuit potential monitored digital photocorrosion of GaAs/AlGaAs quantum well microstructures

NASA Astrophysics Data System (ADS)

Aithal, Srivatsa; Dubowski, Jan J.

2018-04-01

Nanostructuring of semiconductor wafers with an atomic level depth resolution is a challenging task, primarily due to the limited availability of instruments for in situ monitoring of such processes. Conventional digital etching relies on calibration procedures and cumbersome diagnostics applied between or at the end of etching cycles. We have developed a photoluminescence (PL) based process for monitoring in situ digital photocorrosion (DPC) of GaAs/AlGaAs microstructures at rates below 0.2 nm per cycle. In this communication, we demonstrate that DPC of GaAs/AlGaAs microstructures could be monitored with open circuit potential (OCP) measured between the photocorroding surface of a microstructure and an Ag/AgCl reference electrode installed in the sample chamber. The excellent correlation between the position of both PL and OCP maxima indicates that the DPC process could be monitored in situ for materials that do not necessarily exhibit measurable PL emission.

Astrocytic control of synaptic function.

PubMed

Papouin, Thomas; Dunphy, Jaclyn; Tolman, Michaela; Foley, Jeannine C; Haydon, Philip G

2017-03-05

Astrocytes intimately interact with synapses, both morphologically and, as evidenced in the past 20 years, at the functional level. Ultrathin astrocytic processes contact and sometimes enwrap the synaptic elements, sense synaptic transmission and shape or alter the synaptic signal by releasing signalling molecules. Yet, the consequences of such interactions in terms of information processing in the brain remain very elusive. This is largely due to two major constraints: (i) the exquisitely complex, dynamic and ultrathin nature of distal astrocytic processes that renders their investigation highly challenging and (ii) our lack of understanding of how information is encoded by local and global fluctuations of intracellular calcium concentrations in astrocytes. Here, we will review the existing anatomical and functional evidence of local interactions between astrocytes and synapses, and how it underlies a role for astrocytes in the computation of synaptic information.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity'. © 2017 The Author(s).

Prevention of work disability due to musculoskeletal disorders: the challenge of implementing evidence.

PubMed

Loisel, Patrick; Buchbinder, Rachelle; Hazard, Rowland; Keller, Robert; Scheel, Inger; van Tulder, Maurits; Webster, Barbara

2005-12-01

The process of returning disabled workers to work presents numerous challenges. In spite of the growing evidence regarding work disability prevention, little uptake of this evidence has been observed. One reason for limited dissemination of evidence is the complexity of the problem, as it is subject to multiple legal, administrative, social, political, and cultural challenges. A literature review and collection of experts' opinion is presented, on the current evidence for work disability prevention, and barriers to evidence implementation. Recommendations are presented for enhancing implementation of research results. The current evidence regarding work disability prevention shows that some clinical interventions (advice to return to modified work and graded activity programs) and some non-clinical interventions (at a service and policy/community level but not at a practice level) are effective in reducing work absenteeism. Implementation of evidence in work disability is a major challenge because intervention recommendations are often imprecise and not yet practical for immediate use, many barriers exist, and many stakeholders are involved. Future studies should involve all relevant stakeholders and aim at developing new strategies that are effective, efficient, and have a potential for successful implementation. These studies should be based upon a clearer conceptualization of the broader context and inter-relationships that determine return to work outcomes.

Comparing algorithms for automated vessel segmentation in computed tomography scans of the lung: the VESSEL12 study

PubMed Central

Rudyanto, Rina D.; Kerkstra, Sjoerd; van Rikxoort, Eva M.; Fetita, Catalin; Brillet, Pierre-Yves; Lefevre, Christophe; Xue, Wenzhe; Zhu, Xiangjun; Liang, Jianming; Öksüz, İlkay; Ünay, Devrim; Kadipaşaogandcaron;lu, Kamuran; Estépar, Raúl San José; Ross, James C.; Washko, George R.; Prieto, Juan-Carlos; Hoyos, Marcela Hernández; Orkisz, Maciej; Meine, Hans; Hüllebrand, Markus; Stöcker, Christina; Mir, Fernando Lopez; Naranjo, Valery; Villanueva, Eliseo; Staring, Marius; Xiao, Changyan; Stoel, Berend C.; Fabijanska, Anna; Smistad, Erik; Elster, Anne C.; Lindseth, Frank; Foruzan, Amir Hossein; Kiros, Ryan; Popuri, Karteek; Cobzas, Dana; Jimenez-Carretero, Daniel; Santos, Andres; Ledesma-Carbayo, Maria J.; Helmberger, Michael; Urschler, Martin; Pienn, Michael; Bosboom, Dennis G.H.; Campo, Arantza; Prokop, Mathias; de Jong, Pim A.; Ortiz-de-Solorzano, Carlos; Muñoz-Barrutia, Arrate; van Ginneken, Bram

2016-01-01

The VESSEL12 (VESsel SEgmentation in the Lung) challenge objectively compares the performance of different algorithms to identify vessels in thoracic computed tomography (CT) scans. Vessel segmentation is fundamental in computer aided processing of data generated by 3D imaging modalities. As manual vessel segmentation is prohibitively time consuming, any real world application requires some form of automation. Several approaches exist for automated vessel segmentation, but judging their relative merits is difficult due to a lack of standardized evaluation. We present an annotated reference dataset containing 20 CT scans and propose nine categories to perform a comprehensive evaluation of vessel segmentation algorithms from both academia and industry. Twenty algorithms participated in the VESSEL12 challenge, held at International Symposium on Biomedical Imaging (ISBI) 2012. All results have been published at the VESSEL12 website http://vessel12.grand-challenge.org. The challenge remains ongoing and open to new participants. Our three contributions are: (1) an annotated reference dataset available online for evaluation of new algorithms; (2) a quantitative scoring system for objective comparison of algorithms; and (3) performance analysis of the strengths and weaknesses of the various vessel segmentation methods in the presence of various lung diseases. PMID:25113321

Toward reliable and repeatable automated STEM-EDS metrology with high throughput

NASA Astrophysics Data System (ADS)

Zhong, Zhenxin; Donald, Jason; Dutrow, Gavin; Roller, Justin; Ugurlu, Ozan; Verheijen, Martin; Bidiuk, Oleksii

2018-03-01

New materials and designs in complex 3D architectures in logic and memory devices have raised complexity in S/TEM metrology. In this paper, we report about a newly developed, automated, scanning transmission electron microscopy (STEM) based, energy dispersive X-ray spectroscopy (STEM-EDS) metrology method that addresses these challenges. Different methodologies toward repeatable and efficient, automated STEM-EDS metrology with high throughput are presented: we introduce the best known auto-EDS acquisition and quantification methods for robust and reliable metrology and present how electron exposure dose impacts the EDS metrology reproducibility, either due to poor signalto-noise ratio (SNR) at low dose or due to sample modifications at high dose conditions. Finally, we discuss the limitations of the STEM-EDS metrology technique and propose strategies to optimize the process both in terms of throughput and metrology reliability.

Neuropsychiatric features associated with nutritional and metabolic status in a gastric bypass patient.

PubMed

Waserman, Jessica E; Hategan, Ana; Bourgeois, James A

2015-01-01

Bariatric patients may present for psychiatric evaluation due to exacerbation of preexisting psychiatric disorders, new onset psychiatric disorders and/or neuropsychiatric complications associated with abnormal nutritional and metabolic states following the surgical procedure. These neuropsychiatric complications can be insidious, and clinical manifestations may vary, possibly due to the individual central nervous system (CNS) vulnerability to nutritional decline. Lack of awareness of these complications and their symptoms can result in delays in diagnosis and treatment. Identifying and correcting underlying pathophysiologic processes that lead to such neuropsychiatric syndromes can be challenging. We report a case of a patient who developed a protracted course of mood and cognitive disorder after gastric bypass surgery, which illustrates some of the complexities encountered in diagnosing and managing these patients. Copyright © 2015 Elsevier Inc. All rights reserved.

Integral-geometry characterization of photobiomodulation effects on retinal vessel morphology

PubMed Central

Barbosa, Marconi; Natoli, Riccardo; Valter, Kriztina; Provis, Jan; Maddess, Ted

2014-01-01

The morphological characterization of quasi-planar structures represented by gray-scale images is challenging when object identification is sub-optimal due to registration artifacts. We propose two alternative procedures that enhances object identification in the integral-geometry morphological image analysis (MIA) framework. The first variant streamlines the framework by introducing an active contours segmentation process whose time step is recycled as a multi-scale parameter. In the second variant, we used the refined object identification produced in the first variant to perform the standard MIA with exact dilation radius as multi-scale parameter. Using this enhanced MIA we quantify the extent of vaso-obliteration in oxygen-induced retinopathic vascular growth, the preventative effect (by photobiomodulation) of exposure during tissue development to near-infrared light (NIR, 670 nm), and the lack of adverse effects due to exposure to NIR light. PMID:25071966

Characterization and biocompatibility studies of lead free X-ray shielding polymer composite for healthcare application

NASA Astrophysics Data System (ADS)

Singh, Anil Kumar; Singh, Rakesh Kumar; Sharma, Bhupesh; Tyagi, Ajay Kumar

2017-09-01

Lead based X-ray shielding systems are widely being used in healthcare and radiation processing centers to protect technicians, operators and patients from unwanted exposure to ionizing radiation. However, the use of lead is avoided mainly due to its toxic effects on human health and environment, and also discomfort due to heavier in weight. Hence, production of non-toxic, environment friendly, lead-free X-ray shielding system with less weight and good radiation shielding efficiency compared to conventional lead-based shielding systems is a challenging issue and need of the day. The objectives of present study are to develop, characterize and establish synergy of the materials making radiation shielding composition and their biocompatibility without compromising on radiation shielding efficiency and physico-mechanical attributes vis-à-vis lead based systems.

Estimating challenge load due to disease outbreaks and other challenges using reproduction records of sows.

PubMed

Mathur, P K; Herrero-Medrano, J M; Alexandri, P; Knol, E F; ten Napel, J; Rashidi, H; Mulder, H A

2014-12-01

A method was developed and tested to estimate challenge load due to disease outbreaks and other challenges in sows using reproduction records. The method was based on reproduction records from a farm with known disease outbreaks. It was assumed that the reduction in weekly reproductive output within a farm is proportional to the magnitude of the challenge. As the challenge increases beyond certain threshold, it is manifested as an outbreak. The reproduction records were divided into 3 datasets. The first dataset called the Training dataset consisted of 57,135 reproduction records from 10,901 sows from 1 farm in Canada with several outbreaks of porcine reproductive and respiratory syndrome (PRRS). The known disease status of sows was regressed on the traits number born alive, number of losses as a combination of still birth and mummified piglets, and number of weaned piglets. The regression coefficients from this analysis were then used as weighting factors for derivation of an index measure called challenge load indicator. These weighting factors were derived with i) a two-step approach using residuals or year-week solutions estimated from a previous step, and ii) a single-step approach using the trait values directly. Two types of models were used for each approach: a logistic regression model and a general additive model. The estimates of challenge load indicator were then compared based on their ability to detect PRRS outbreaks in a Test dataset consisting of records from 65,826 sows from 15 farms in the Netherlands. These farms differed from the Canadian farm with respect to PRRS virus strains, severity and frequency of outbreaks. The single-step approach using a general additive model was best and detected 14 out of the 15 outbreaks. This approach was then further validated using the third dataset consisting of reproduction records of 831,855 sows in 431 farms located in different countries in Europe and America. A total of 41 out of 48 outbreaks detected using data analysis were confirmed based on diagnostic information received from the farms. Among these, 30 outbreaks were due to PRRS while 11 were due to other diseases and challenging conditions. The results suggest that proposed method could be useful for estimation of challenge load and detection of challenge phases such as disease outbreaks.

The Challenge of Timely, Responsive and Rigorous Ethics Review of Disaster Research: Views of Research Ethics Committee Members.

PubMed

Hunt, Matthew; Tansey, Catherine M; Anderson, James; Boulanger, Renaud F; Eckenwiler, Lisa; Pringle, John; Schwartz, Lisa

2016-01-01

Research conducted following natural disasters such as earthquakes, floods or hurricanes is crucial for improving relief interventions. Such research, however, poses ethical, methodological and logistical challenges for researchers. Oversight of disaster research also poses challenges for research ethics committees (RECs), in part due to the rapid turnaround needed to initiate research after a disaster. Currently, there is limited knowledge available about how RECs respond to and appraise disaster research. To address this knowledge gap, we investigated the experiences of REC members who had reviewed disaster research conducted in low- or middle-income countries. We used interpretive description methodology and conducted in-depth interviews with 15 respondents. Respondents were chairs, members, advisors, or coordinators from 13 RECs, including RECs affiliated with universities, governments, international organizations, a for-profit REC, and an ad hoc committee established during a disaster. Interviews were analyzed inductively using constant comparative techniques. Through this process, three elements were identified as characterizing effective and high-quality review: timeliness, responsiveness and rigorousness. To ensure timeliness, many RECs rely on adaptations of review procedures for urgent protocols. Respondents emphasized that responsive review requires awareness of and sensitivity to the particularities of disaster settings and disaster research. Rigorous review was linked with providing careful assessment of ethical considerations related to the research, as well as ensuring independence of the review process. Both the frequency of disasters and the conduct of disaster research are on the rise. Ensuring effective and high quality review of disaster research is crucial, yet challenges, including time pressures for urgent protocols, exist for achieving this goal. Adapting standard REC procedures may be necessary. However, steps should be taken to ensure that ethics review of disaster research remains diligent and thorough.

Multimodal Wireless Sensor Network-Based Ambient Assisted Living in Real Homes with Multiple Residents

PubMed Central

Tunca, Can; Alemdar, Hande; Ertan, Halil; Incel, Ozlem Durmaz; Ersoy, Cem

2014-01-01

Human activity recognition and behavior monitoring in a home setting using wireless sensor networks (WSNs) provide a great potential for ambient assisted living (AAL) applications, ranging from health and wellbeing monitoring to resource consumption monitoring. However, due to the limitations of the sensor devices, challenges in wireless communication and the challenges in processing large amounts of sensor data in order to recognize complex human activities, WSN-based AAL systems are not effectively integrated in the home environment. Additionally, given the variety of sensor types and activities, selecting the most suitable set of sensors in the deployment is an important task. In order to investigate and propose solutions to such challenges, we introduce a WSN-based multimodal AAL system compatible for homes with multiple residents. Particularly, we focus on the details of the system architecture, including the challenges of sensor selection, deployment, networking and data collection and provide guidelines for the design and deployment of an effective AAL system. We also present the details of the field study we conducted, using the systems deployed in two different real home environments with multiple residents. With these systems, we are able to collect ambient sensor data from multiple homes. This data can be used to assess the wellbeing of the residents and identify deviations from everyday routines, which may be indicators of health problems. Finally, in order to elaborate on the possible applications of the proposed AAL system and to exemplify directions for processing the collected data, we provide the results of several human activity inference experiments, along with examples on how such results could be interpreted. We believe that the experiences shared in this work will contribute towards accelerating the acceptance of WSN-based AAL systems in the home setting. PMID:24887044

The Challenge of Timely, Responsive and Rigorous Ethics Review of Disaster Research: Views of Research Ethics Committee Members

PubMed Central

Hunt, Matthew; Tansey, Catherine M.

2016-01-01

Background Research conducted following natural disasters such as earthquakes, floods or hurricanes is crucial for improving relief interventions. Such research, however, poses ethical, methodological and logistical challenges for researchers. Oversight of disaster research also poses challenges for research ethics committees (RECs), in part due to the rapid turnaround needed to initiate research after a disaster. Currently, there is limited knowledge available about how RECs respond to and appraise disaster research. To address this knowledge gap, we investigated the experiences of REC members who had reviewed disaster research conducted in low- or middle-income countries. Methods We used interpretive description methodology and conducted in-depth interviews with 15 respondents. Respondents were chairs, members, advisors, or coordinators from 13 RECs, including RECs affiliated with universities, governments, international organizations, a for-profit REC, and an ad hoc committee established during a disaster. Interviews were analyzed inductively using constant comparative techniques. Results Through this process, three elements were identified as characterizing effective and high-quality review: timeliness, responsiveness and rigorousness. To ensure timeliness, many RECs rely on adaptations of review procedures for urgent protocols. Respondents emphasized that responsive review requires awareness of and sensitivity to the particularities of disaster settings and disaster research. Rigorous review was linked with providing careful assessment of ethical considerations related to the research, as well as ensuring independence of the review process. Conclusion Both the frequency of disasters and the conduct of disaster research are on the rise. Ensuring effective and high quality review of disaster research is crucial, yet challenges, including time pressures for urgent protocols, exist for achieving this goal. Adapting standard REC procedures may be necessary. However, steps should be taken to ensure that ethics review of disaster research remains diligent and thorough. PMID:27327165

Multimodal wireless sensor network-based ambient assisted living in real homes with multiple residents.

PubMed

Tunca, Can; Alemdar, Hande; Ertan, Halil; Incel, Ozlem Durmaz; Ersoy, Cem

2014-05-30

Human activity recognition and behavior monitoring in a home setting using wireless sensor networks (WSNs) provide a great potential for ambient assisted living (AAL) applications, ranging from health and wellbeing monitoring to resource consumption monitoring. However, due to the limitations of the sensor devices, challenges in wireless communication and the challenges in processing large amounts of sensor data in order to recognize complex human activities, WSN-based AAL systems are not effectively integrated in the home environment. Additionally, given the variety of sensor types and activities, selecting the most suitable set of sensors in the deployment is an important task. In order to investigate and propose solutions to such challenges, we introduce a WSN-based multimodal AAL system compatible for homes with multiple residents. Particularly, we focus on the details of the system architecture, including the challenges of sensor selection, deployment, networking and data collection and provide guidelines for the design and deployment of an effective AAL system. We also present the details of the field study we conducted, using the systems deployed in two different real home environments with multiple residents. With these systems, we are able to collect ambient sensor data from multiple homes. This data can be used to assess the wellbeing of the residents and identify deviations from everyday routines, which may be indicators of health problems. Finally, in order to elaborate on the possible applications of the proposed AAL system and to exemplify directions for processing the collected data, we provide the results of several human activity inference experiments, along with examples on how such results could be interpreted. We believe that the experiences shared in this work will contribute towards accelerating the acceptance of WSN-based AAL systems in the home setting.

Towards roll-to-roll manufacturing of polymer photonic devices

NASA Astrophysics Data System (ADS)

Subbaraman, Harish; Lin, Xiaohui; Ling, Tao; Guo, L. Jay; Chen, Ray T.

2014-03-01

Traditionally, polymer photonic devices are fabricated using clean-room processes such as photolithography, e-beam lithography, reactive ion etching (RIE) and lift-off methods etc, which leads to long fabrication time, low throughput and high cost. We have utilized a novel process for fabricating polymer photonic devices using a combination of imprinting and ink jet printing methods, which provides high throughput on a variety of rigid and flexible substrates with low cost. We discuss the manufacturing challenges that need to be overcome in order to realize true implementation of roll-to-roll manufacturing of flexible polymer photonic systems. Several metrology and instrumentation challenges involved such as availability of particulate-free high quality substrate, development and implementation of high-speed in-line and off-line inspection and diagnostic tools with adaptive control for patterned and unpatterned material films, development of reliable hardware, etc need to be addressed and overcome in order to realize a successful manufacturing process. Due to extreme resolution requirements compared to print media, the burden of software and hardware tools on the throughput also needs to be carefully determined. Moreover, the effect of web wander and variations in web speed need to accurately be determined in the design of the system hardware and software. In this paper, we show the realization of solutions for few challenges, and utilizing these solutions for developing a high-rate R2R dual stage ink-jet printer that can provide alignment accuracy of <10μm at a web speed of 5m/min. The development of a roll-to-roll manufacturing system for polymer photonic systems opens limitless possibilities for the deployment of high performance components in a variety of applications including communication, sensing, medicine, agriculture, energy, lighting etc.

Small scale rainfall simulators: Challenges for a future use in soil erosion research

NASA Astrophysics Data System (ADS)

Ries, Johannes B.; Iserloh, Thomas; Seeger, Manuel

2013-04-01

Rainfall simulation on micro-plot scale is a method used worldwide to assess the generation of overland flow, soil erosion, infiltration and interrelated processes such as soil sealing, crusting, splash and redistribution of solids and solutes. The produced data are of great significance not only for the analysis of the simulated processes, but also as a source of input-data for soil erosion modelling. The reliability of the data is therefore of paramount importance, and quality management of rainfall simulation procedure a general responsibility of the rainfall simulation community. This was an accepted outcome at the "International Rainfall Simulator Workshop 2011" at Trier University. The challenges of the present and near future use of small scale rainfall simulations concern the comparability of results and scales, the quality of the data for soil erosion modelling, and further technical developments to overcome physical limitations and constraints. Regarding the high number of research questions, different fields of application, and due to the great technical creativity of researchers, a large number of different types of rainfall simulators is available. But each of the devices produces a different rainfall, leading to different kinetic energy values influencing soil surface and erosion processes. Plot sizes are also variable, as well as the experimental simulation procedures. As a consequence, differing runoff and erosion results are produced. The presentation summarises the three important aspects of rainfall simulations, following a processual order: 1. Input-factor "rain" and its calibration 2. Surface-factor "plot" and its documentation 3. Output-factors "runoff" and "sediment concentration" Finally, general considerations about the limitations and challenges for further developments and applications of rainfall simulation data are presented.

Challenges in Developing Models Describing Complex Soil Systems

NASA Astrophysics Data System (ADS)

Simunek, J.; Jacques, D.

2014-12-01

Quantitative mechanistic models that consider basic physical, mechanical, chemical, and biological processes have the potential to be powerful tools to integrate our understanding of complex soil systems, and the soil science community has often called for models that would include a large number of these diverse processes. However, once attempts have been made to develop such models, the response from the community has not always been overwhelming, especially after it discovered that these models are consequently highly complex, requiring not only a large number of parameters, not all of which can be easily (or at all) measured and/or identified, and which are often associated with large uncertainties, but also requiring from their users deep knowledge of all/most of these implemented physical, mechanical, chemical and biological processes. Real, or perceived, complexity of these models then discourages users from using them even for relatively simple applications, for which they would be perfectly adequate. Due to the nonlinear nature and chemical/biological complexity of the soil systems, it is also virtually impossible to verify these types of models analytically, raising doubts about their applicability. Code inter-comparisons, which is then likely the most suitable method to assess code capabilities and model performance, requires existence of multiple models of similar/overlapping capabilities, which may not always exist. It is thus a challenge not only to developed models describing complex soil systems, but also to persuade the soil science community in using them. As a result, complex quantitative mechanistic models are still an underutilized tool in soil science research. We will demonstrate some of the challenges discussed above on our own efforts in developing quantitative mechanistic models (such as HP1/2) for complex soil systems.

Challenges and opportunities to improve understanding on wetland ecosystem and function at the local catchment scale: data fusion, data-model integration, and prediction uncertainty.

NASA Astrophysics Data System (ADS)

Yeo, I. Y.

2016-12-01

Wetlands are valuable landscape features that provide important ecosystem functions and services. The ecosystem processes in wetlands are highly dependent on the hydrology. However, hydroperiod (i.e., change dynamics in inundation extent) is highly variable spatially and temporarily, and extremely difficult to predict owing to the complexity in hydrological processes within wetlands and its interaction with surrounding areas. This study reports the challenges and progress in assessing the catchment scale benefits of wetlands to regulate hydrological regime and water quality improvement in agricultural watershed. A process-based watershed model, Soil and Water Assessment Tool (SWAT) was improved to simulate the cumulative impacts of wetlands on downstream. Newly developed remote sensing products from LiDAR intensity and time series Landsat records, which show the inter-annual changes in fraction inundation, were utilized to describe the change status of inundated areas within forested wetlands, develop spatially varying wetland parameters, and evaluate the predicted inundated areas at the landscape level. We outline the challenges on developing the time series inundation mapping products at a high spatial and temporal resolution and reconciling the catchment scale model with the moderate remote sensing products. We then highlight the importance of integrating spatialized information to model calibration and evaluation to address the issues of equi-finality and prediction uncertainty. This integrated approach was applied to the upper region of Choptank River Watershed, the agricultural watershed in the Coastal Plain of Chesapeake Bay Watershed (in US). In the Mid- Atlantic US, the provision of pollution regulation services provided by wetlands has been emphasized due to declining water quality within the Chesapeake Bay and watersheds, and the preservation and restoration of wetlands has become the top priority to manage nonpoint source water pollution.

Recruiting primary care practices for practice-based research: a case study of a group-randomized study (TRANSLATE CKD) recruitment process.

PubMed

Loskutova, Natalia Y; Smail, Craig; Ajayi, Kemi; Pace, Wilson D; Fox, Chester H

2018-01-16

We assessed the challenging process of recruiting primary care practices in a practice-based research study. In this descriptive case study of recruitment data collected for a large practice-based study (TRANSLATE CKD), 48 single or multiple-site health care organizations in the USA with a total of 114 practices were invited to participate. We collected quantitative and qualitative measures of recruitment process and outcomes for the first 25 practices recruited. Information about 13 additional practices is not provided due to staff transitions and limited data collection resources. Initial outreach was made to 114 practices (from 48 organizations, 41% small); 52 (45%) practices responded with interest. Practices enrolled in the study (n = 25) represented 22% of the total outreach number, or 48% of those initially interested. Average time to enroll was 71 calendar days (range 11-107). There was no difference in the number of days practices remained under recruitment, based on enrolled versus not enrolled (44.8 ± 30.4 versus 46.8 ± 25.4 days, P = 0.86) or by the organization size, i.e. large versus small (defined by having ≤4 distinct practices; 52 ± 23.6 versus 43.6 ± 27.8 days; P = 0.46). The most common recruitment barriers were administrative, e.g. lack of perceived direct organizational benefit, and were more prominent among large organizations. Despite the general belief that the research topic, invitation method, and interest in research may facilitate practice recruitment, our results suggest that most of the recruitment challenges represent managerial challenges. Future research projects may need to consider relevant methodologies from businesses administration and marketing fields. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Scalable imprinting of shape-specific polymeric nanocarriers using a release layer of switchable water solubility.

PubMed

Agarwal, Rachit; Singh, Vikramjit; Jurney, Patrick; Shi, Li; Sreenivasan, S V; Roy, Krishnendu

2012-03-27

There is increasing interest in fabricating shape-specific polymeric nano- and microparticles for efficient delivery of drugs and imaging agents. The size and shape of these particles could significantly influence their transport properties and play an important role in in vivo biodistribution, targeting, and cellular uptake. Nanoimprint lithography methods, such as jet-and-flash imprint lithography (J-FIL), provide versatile top-down processes to fabricate shape-specific, biocompatible nanoscale hydrogels that can deliver therapeutic and diagnostic molecules in response to disease-specific cues. However, the key challenges in top-down fabrication of such nanocarriers are scalable imprinting with biological and biocompatible materials, ease of particle-surface modification using both aqueous and organic chemistry as well as simple yet biocompatible harvesting. Here we report that a biopolymer-based sacrificial release layer in combination with improved nanocarrier-material formulation can address these challenges. The sacrificial layer improves scalability and ease of imprint-surface modification due to its switchable solubility through simple ion exchange between monovalent and divalent cations. This process enables large-scale bionanoimprinting and efficient, one-step harvesting of hydrogel nanoparticles in both water- and organic-based imprint solutions. © 2012 American Chemical Society

Proteins for breaking barriers in lignocellulosic bioethanol production.

PubMed

Ulaganathan, Kandasamy; Goud, Burragoni S; Reddy, Mettu M; Kumar, Vanaparthi P; Balsingh, Jatoth; Radhakrishna, Surabhi

2015-01-01

Reduction in fossil fuel consumption by using alternate sources of energy is a major challenge facing mankind in the coming decades. Bioethanol production using lignocellulosic biomass is the most viable option for addressing this challenge. Industrial bioconversion of lignocellulosic biomass, though possible now, is not economically viable due to presence of barriers that escalate the cost of production. As cellulose and hemicellulose are the major constituents of terrestrial biomass, which is available in massive quantities, hydrolysis of cellulose and hemicellulose by the microorganisms are the most prominent biochemical processes happening in the earth. Microorganisms possess different categories of proteins associated with different stages of bioethanol production and a number of them are already found and characterized. Many more of these proteins need to be identified which suit the specificities needed for the bioethanol production process. Discovery of proteins with novel specificities and application of genetic engineering technologies to harvest the synergies existing between them with the aim to develop consolidated bioprocess is the major direction of research in the future. In this review, we discuss the different categories of proteins used for bioethanol production in the context of breaking the barriers existing for the economically feasible lignocellulosic bioethanol production.

Computer-aided biochemical programming of synthetic microreactors as diagnostic devices.

PubMed

Courbet, Alexis; Amar, Patrick; Fages, François; Renard, Eric; Molina, Franck

2018-04-26

Biological systems have evolved efficient sensing and decision-making mechanisms to maximize fitness in changing molecular environments. Synthetic biologists have exploited these capabilities to engineer control on information and energy processing in living cells. While engineered organisms pose important technological and ethical challenges, de novo assembly of non-living biomolecular devices could offer promising avenues toward various real-world applications. However, assembling biochemical parts into functional information processing systems has remained challenging due to extensive multidimensional parameter spaces that must be sampled comprehensively in order to identify robust, specification compliant molecular implementations. We introduce a systematic methodology based on automated computational design and microfluidics enabling the programming of synthetic cell-like microreactors embedding biochemical logic circuits, or protosensors , to perform accurate biosensing and biocomputing operations in vitro according to temporal logic specifications. We show that proof-of-concept protosensors integrating diagnostic algorithms detect specific patterns of biomarkers in human clinical samples. Protosensors may enable novel approaches to medicine and represent a step toward autonomous micromachines capable of precise interfacing of human physiology or other complex biological environments, ecosystems, or industrial bioprocesses. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

Implementation of clinical research trials using web-based and mobile devices: challenges and solutions.

PubMed

Eagleson, Roy; Altamirano-Diaz, Luis; McInnis, Alex; Welisch, Eva; De Jesus, Stefanie; Prapavessis, Harry; Rombeek, Meghan; Seabrook, Jamie A; Park, Teresa; Norozi, Kambiz

2017-03-17

With the increasing implementation of web-based, mobile health interventions in clinical trials, it is crucial for researchers to address the security and privacy concerns of patient information according to high ethical standards. The full process of meeting these standards is often made more complicated due to the use of internet-based technology and smartphones for treatment, telecommunication, and data collection; however, this process is not well-documented in the literature. The Smart Heart Trial is a single-arm feasibility study that is currently assessing the effects of a web-based, mobile lifestyle intervention for overweight and obese children and youth with congenital heart disease in Southwestern Ontario. Participants receive telephone counseling regarding nutrition and fitness; and complete goal-setting activities on a web-based application. This paper provides a detailed overview of the challenges the study faced in meeting the high standards of our Research Ethics Board, specifically regarding patient privacy. We outline our solutions, successes, limitations, and lessons learned to inform future similar studies; and model much needed transparency in ensuring high quality security and protection of patient privacy when using web-based and mobile devices for telecommunication and data collection in clinical research.

Quantum mechanical prediction of four-phonon scattering rates and reduced thermal conductivity of solids

NASA Astrophysics Data System (ADS)

Feng, Tianli; Ruan, Xiulin

2016-01-01

Recently, first principle-based predictions of lattice thermal conductivity κ from perturbation theory have achieved significant success. However, it only includes three-phonon scattering due to the assumption that four-phonon and higher-order processes are generally unimportant. Also, directly evaluating the scattering rates of four-phonon and higher-order processes has been a long-standing challenge. In this work, however, we have developed a formalism to explicitly determine quantum mechanical scattering probability matrices for four-phonon scattering in the full Brillouin zone, and by mitigating the computational challenge we have directly calculated four-phonon scattering rates. We find that four-phonon scattering rates are comparable to three-phonon scattering rates at medium and high temperatures, and they increase quadratically with temperature. As a consequence, κ of Lennard-Jones argon is reduced by more than 60% at 80 K when four-phonon scattering is included. Also, in less anharmonic materials—diamond, silicon, and germanium—κ is still reduced considerably at high temperature by four-phonon scattering by using the classical Tersoff potentials. Also, the thermal conductivity of optical phonons is dominated by the fourth- and higher-orders phonon scattering even at low temperature.

Report of the Presidential Commission on the Space Shuttle Challenger Accident, Volume 1

NASA Technical Reports Server (NTRS)

Rogers, W. P.; Armstrong, N. A.; Acheson, D. C.; Covert, E. E.; Feynman, R. P.; Hotz, R. B.; Kutyna, D. J.; Ride, S. K.; Rummel, R. W.; Sutter, J. F.

1986-01-01

The findings of the Commission regarding the circumstances surrounding the Challenger accident are reported and recommendations for corrective action are outlined. All available mission data, subsequent tests, and wreckage analyses were reviewed and specific failure scenarios were developed. The Commission concluded that the cause of the Mission 51-L accident was the failure of the pressure seal in the aft field joint of the right solid rocket motor. The failure was due to a faulty design unacceptably sensitive to a number of factors. These factors were the effects of temperature, physical dimensions, the character of materials, the effects of reuse, processing, and the reaction of the joint to dynamic loading. In addition to analyzing the material causes of the accident, the Commission examined the chain of decisions that culminated in approval of the launch. It concluded that the decision making process was flawed in several ways including (1) failure in communication resulting in a launch decision based on incomplete and misleading information, (2) a conflict between engineering data and management judgements, and (3) a NASA management structure that permitted flight safety problems to bypass key Shuttle managers.

Interactive target tracking for persistent wide-area surveillance

NASA Astrophysics Data System (ADS)

Ersoy, Ilker; Palaniappan, Kannappan; Seetharaman, Guna S.; Rao, Raghuveer M.

2012-06-01

Persistent aerial surveillance is an emerging technology that can provide continuous, wide-area coverage from an aircraft-based multiple-camera system. Tracking targets in these data sets is challenging for vision algorithms due to large data (several terabytes), very low frame rate, changing viewpoint, strong parallax and other imperfections due to registration and projection. Providing an interactive system for automated target tracking also has additional challenges that require online algorithms that are seamlessly integrated with interactive visualization tools to assist the user. We developed an algorithm that overcomes these challenges and demonstrated it on data obtained from a wide-area imaging platform.

Autism: a transdiagnostic, dimensional, construct of reasoning?

PubMed

Aggernaes, Bodil

2018-03-01

The concept of autism has changed across time, from the Bleulerian concept, which defined it as one of several symptoms of dementia praecox, to the present-day concept representing a pervasive development disorder. The present theoretical contribution to this special issue of EJN on autism introduces new theoretical ideas and discusses them in light of selected prior theories, clinical examples, and recent empirical evidence. The overall aim is to identify some present challenges of diagnostic practice and autism research and to suggest new pathways that may help direct future research. Future research must agree on the definitions of core concepts such as autism and psychosis. A possible redefinition of the concept of autism may be a condition in which the rationale of an individual's behaviour differs qualitatively from that of the social environment due to characteristic cognitive impairments affecting reasoning. A broad concept of psychosis could focus on deviances in the experience of reality resulting from impairments of reasoning. In this light and consistent with recent empirical evidence, it may be appropriate to redefine dementia praecox as a developmental disorder of reasoning. A future challenge of autism research may be to develop theoretical models that can account for the impact of complex processes acting at the social level in addition to complex neurobiological and psychological processes. Such models could profit from a distinction among processes related to (i) basic susceptibility, (ii) adaptive processes and (iii) decompensating factors involved in the development of manifest illness. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

How organizational context affects bioethical decision-making: pharmacists' management of gatekeeping processes in retail and hospital settings.

PubMed

Chiarello, Elizabeth

2013-12-01

Social science studies of bioethics demonstrate that ethics are highly contextual, functioning differently across local settings as actors make daily decisions "on the ground." Sociological studies that demonstrate the key role organizations play in shaping ethical decision-making have disproportionately focused on physicians and nurses working in hospital settings where they contend with life and death issues. This study broadens our understanding of the contexts of ethical decision-making by empirically examining understudied healthcare professionals - pharmacists - working in two organizational settings, retail and hospital, where they act as gatekeepers to regulated goods and services as they contend with ethical issues ranging from the serious to the mundane. This study asks: How do organizations shape pharmacists' identification, negotiation, and resolution of ethical challenges; in other words, how do organizations shape pharmacists' gatekeeping processes? Based on 95 semi-structured interviews with U.S. pharmacists practicing in retail and hospital pharmacies conducted between September 2009 and May 2011, this research finds that organizations influence ethical decision-making by shaping how pharmacists construct four gatekeeping processes: medical, legal, fiscal, and moral. Each gatekeeping process manifests differently across organizations due to how these settings structure inter-professional power dynamics, proximity to patients, and means of accessing information. Findings suggest new directions for theorizing about ethical decision-making in medical contexts by drawing attention to new ethical actors, new organizational settings, an expanded definition of ethical challenges, and a broader conceptualization of gatekeeping. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Process of Translation and Linguistic Validation of the Functional Assessment of Cancer Therapy-Brain Quality of Life Instrument from English to Malayalam: The Challenges Faced.

PubMed

Menon, Durgapoorna; Venkateswaran, Chitra

2017-01-01

Both brain tumors and their treatments have a major negative impact on the quality of life (QoL). EORTC BN20 and Functional Assessment of Cancer Therapy-Brain (FACT-BR) are the most commonly used tools to assess QoL. The FACT-BR is a 23-item questionnaire, especially about the psychosocial aspects of QoL. This paper describes the challenges we faced during the process of translation and validation of the FACT-BR into Malayalam. We first screened the patients to ensure their mental status was satisfactory and that they could communicate well in both languages. According to the Functional Assessment of Chronic Illness Therapy methodology, there were two forward translations from English to Malayalam by two independent translators, a reconciliation of the two forward translations, a back-translation into English, a review/finalization by a fifth translator, proofreading, and then testing on a small cohort of patients. The whole process of translation was fraught with small and large hurdles - from small technical issues to the gaps in sociocultural norms. The sub item BR 7, due to the lack of an exact equivalent word, had issues that persisted up to the validation phase. The postquestionnaire debriefing interviews confirmed that the translations were well understood and conceptually equivalent to the original English one. Translation of the FACT-BR into Malayalam nearly completely reproduced the concepts of the original English questionnaire, as proved in the subsequent validation process.

Critical elements in implementations of just-in-time management: empirical study of cement industry in Pakistan.

PubMed

Qureshi, Muhammad Imran; Iftikhar, Mehwish; Bhatti, Mansoor Nazir; Shams, Tauqeer; Zaman, Khalid

2013-01-01

In recent years, inventory management is continuous challenge for all organizations not only due to heavy cost associated with inventory holding, but also it has a great deal to do with the organizations production process. Cement industry is a growing sector of Pakistan's economy which is now facing problems in capacity utilization of their plants. This study attempts to identify the key strategies for successful implementation of just-in-time (JIT) management philosophy on the cement industry of Pakistan. The study uses survey responses from four hundred operations' managers of cement industry in order to know about the advantages and benefits that cement industry have experienced by Just in time (JIT) adoption. The results show that implementing the quality, product design, inventory management, supply chain and production plans embodied through the JIT philosophy which infect enhances cement industry competitiveness in Pakistan. JIT implementation increases performance by lower level of inventory, reduced operations & inventory costs was reduced eliminates wastage from the processes and reduced unnecessary production which is a big challenge for the manufacturer who are trying to maintain the continuous flow processes. JIT implementation is a vital manufacturing strategy that reaches capacity utilization and minimizes the rate of defect in continuous flow processes. The study emphasize the need for top management commitment in order to incorporate the necessary changes that need to take place in cement industry so that JIT implementation can take place in an effective manner.

Dimensional accuracy of aluminium extrusions in mechanical calibration

NASA Astrophysics Data System (ADS)

Raknes, Christian Arne; Welo, Torgeir; Paulsen, Frode

2018-05-01

Reducing dimensional variations in the extrusion process without increasing cost is challenging due to the nature of the process itself. An alternative approach—also from a cost perspective—is using extruded profiles with standard tolerances and utilize downstream processes, and thus calibrate the part within tolerance limits that are not achievable directly from the extrusion process. In this paper, two mechanical calibration strategies for the extruded product are investigated, utilizing the forming lines of the manufacturer. The first calibration strategy is based on global, longitudinal stretching in combination with local bending, while the second strategy utilizes the principle of transversal stretching and local bending of the cross-section. An extruded U-profile is used to make a comparison between the two methods using numerical analyses. To provide response surfaces with the FEA program, ABAQUS is used in combination with Design of Experiment (DOE). DOE is conducted with a two-level fractional factorial design to collect the appropriate data. The aim is to find the main factors affecting the dimension accuracy of the final part obtained by the two calibration methods. The results show that both calibration strategies have proven to reduce cross-sectional variations effectively form standard extrusion tolerances. It is concluded that mechanical calibration is a viable, low-cost alternative for aluminium parts that demand high dimensional accuracy, e.g. due to fit-up or welding requirements.

Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles

PubMed Central

Wei, Xi; Syed, Abeer; Mao, Pan; Han, Jongyoon; Song, Yong-Ak

2016-01-01

Polydimethylsiloxane (PDMS) is the prevailing building material to make microfluidic devices due to its ease of molding and bonding as well as its transparency. Due to the softness of the PDMS material, however, it is challenging to use PDMS for building nanochannels. The channels tend to collapse easily during plasma bonding. In this paper, we present an evaporation-driven self-assembly method of silica colloidal nanoparticles to create nanofluidic junctions with sub-50 nm pores between two microchannels. The pore size as well as the surface charge of the nanofluidic junction is tunable simply by changing the colloidal silica bead size and surface functionalization outside of the assembled microfluidic device in a vial before the self-assembly process. Using the self-assembly of nanoparticles with a bead size of 300 nm, 500 nm, and 900 nm, it was possible to fabricate a porous membrane with a pore size of ~45 nm, ~75 nm and ~135 nm, respectively. Under electrical potential, this nanoporous membrane initiated ion concentration polarization (ICP) acting as a cation-selective membrane to concentrate DNA by ~1,700 times within 15 min. This non-lithographic nanofabrication process opens up a new opportunity to build a tunable nanofluidic junction for the study of nanoscale transport processes of ions and molecules inside a PDMS microfluidic chip. PMID:27023724

Sustainability Characterization for Additive Manufacturing.

PubMed

Mani, Mahesh; Lyons, Kevin W; Gupta, S K

2014-01-01

Additive manufacturing (AM) has the potential to create geometrically complex parts that require a high degree of customization, using less material and producing less waste. Recent studies have shown that AM can be an economically viable option for use by the industry, yet there are some inherent challenges associated with AM for wider acceptance. The lack of standards in AM impedes its use for parts production since industries primarily depend on established standards in processes and material selection to ensure the consistency and quality. Inability to compare AM performance against traditional manufacturing methods can be a barrier for implementing AM processes. AM process sustainability has become a driver due to growing environmental concerns for manufacturing. This has reinforced the importance to understand and characterize AM processes for sustainability. Process characterization for sustainability will help close the gaps for comparing AM performance to traditional manufacturing methods. Based on a literature review, this paper first examines the potential environmental impacts of AM. A methodology for sustainability characterization of AM is then proposed to serve as a resource for the community to benchmark AM processes for sustainability. Next, research perspectives are discussed along with relevant standardization efforts.

Combined heterogeneous Electro-Fenton and biological process for the treatment of stabilized landfill leachate.

PubMed

Baiju, Archa; Gandhimathi, R; Ramesh, S T; Nidheesh, P V

2018-03-15

Treatment of stabilized landfill leachate is a great challenge due to its poor biodegradability. Present study made an attempt to treat this wastewater by combining electro-Fenton (E-Fenton) and biological process. E-Fenton treatment was applied prior to biological process to enhance the biodegradability of leachate, which will be beneficial for the subsequent biological process. This study also investigates the efficiency of iron molybdophosphate (FeMoPO) nanoparticles as a heterogeneous catalyst in E-Fenton process. The effects of initial pH, catalyst dosage, applied voltage and electrode spacing on Chemical Oxygen Demand (COD) removal efficiency were analyzed to determine the optimum conditions. Heterogeneous E-Fenton process gave 82% COD removal at pH 2, catalyst dosage of 50 mg/L, voltage 5 V, electrode spacing 3 cm and electrode area 25 cm 2 . Combined E-Fenton and biological treatment resulted an overall COD removal of 97%, bringing down the final COD to 192 mg/L. Copyright © 2018 Elsevier Ltd. All rights reserved.

Systems view on spatial planning and perception based on invariants in agent-environment dynamics

PubMed Central

Mettler, Bérénice; Kong, Zhaodan; Li, Bin; Andersh, Jonathan

2015-01-01

Modeling agile and versatile spatial behavior remains a challenging task, due to the intricate coupling of planning, control, and perceptual processes. Previous results have shown that humans plan and organize their guidance behavior by exploiting patterns in the interactions between agent or organism and the environment. These patterns, described under the concept of Interaction Patterns (IPs), capture invariants arising from equivalences and symmetries in the interaction with the environment, as well as effects arising from intrinsic properties of human control and guidance processes, such as perceptual guidance mechanisms. The paper takes a systems' perspective, considering the IP as a unit of organization, and builds on its properties to present a hierarchical model that delineates the planning, control, and perceptual processes and their integration. The model's planning process is further elaborated by showing that the IP can be abstracted, using spatial time-to-go functions. The perceptual processes are elaborated from the hierarchical model. The paper provides experimental support for the model's ability to predict the spatial organization of behavior and the perceptual processes. PMID:25628524

Predictive modeling of solidification during laser additive manufacturing of nickel superalloys: recent developments, future directions

NASA Astrophysics Data System (ADS)

Ghosh, Supriyo

2018-01-01

Additive manufacturing (AM) processes produce parts with improved physical, chemical, and mechanical properties compared to conventional manufacturing processes. In AM processes, intricate part geometries are produced from multicomponent alloy powder, in a layer-by-layer fashion with multipass laser melting, solidification, and solid-state phase transformations, in a shorter manufacturing time, with minimal surface finishing, and at a reasonable cost. However, there is an increasing need for post-processing of the manufactured parts via, for example, stress relieving heat treatment and hot isostatic pressing to achieve homogeneous microstructure and properties at all times. Solidification in an AM process controls the size, shape, and distribution of the grains, the growth morphology, the elemental segregation and precipitation, the subsequent solid-state phase changes, and ultimately the material properties. The critical issues in this process are linked with multiphysics (such as fluid flow and diffusion of heat and mass) and multiscale (lengths, times and temperature ranges) challenges that arise due to localized rapid heating and cooling during AM processing. The alloy chemistry-process-microstructure-property-performance correlation in this process will be increasingly better understood through multiscale modeling and simulation.

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

Marra, James; Kim, Dong -Sang; Maio, Vincent

A number of waste components in US defense high level radioactive wastes (HLW) have proven challenging for current Joule heated ceramic melter (JHCM) operations and have limited the ability to increase waste loadings beyond already realized levels. Many of these “troublesome" waste species cause crystallization in the glass melt that can negatively impact product quality or have a deleterious effect on melter processing. Recent efforts at US Department of Energy laboratories have focused on understanding crystallization behavior within HLW glass melts and investigating approaches to mitigate the impacts of crystallization so that increases in waste loading can be realized. Advancedmore » glass formulations have been developed to highlight the unique benefits of next-generation melter technologies such as the Cold Crucible Induction Melter (CCIM). Crystal-tolerant HLW glasses have been investigated to allow sparingly soluble components such as chromium to crystallize in the melter but pass out of the melter before accumulating.The Hanford site AZ-101 tank waste composition represents a waste group that is waste loading limited primarily due to high concentrations of Fe 2O 3 (also with high Al 2O 3 concentrations). Systematic glass formulation development utilizing slightly higher process temperatures and higher tolerance to spinel crystals demonstrated that an increase in waste loading of more than 20% could be achieved for this waste composition, and by extension higher loadings for wastes in the same group. An extended duration CCIM melter test was conducted on an AZ-101 waste simulant using the CCIM platform at the Idaho National Laboratory (INL). The melter was continually operated for approximately 80 hours demonstrating that the AZ-101 high waste loading glass composition could be readily processed using the CCIM technology. The resulting glass was close to the targeted composition and exhibited excellent durability in both the as poured state and after being slowly cooled according to the canister centerline cooling (CCC) profile. Glass formulation development was also completed on other Hanford tank wastes that were identified to further challenge waste loading due to the presence of appreciable quantities (>750 g) of plutonium in the waste tanks. In addition to containing appreciable Pu quantities, the C-102 waste tank and the 244-TX waste tank contain high concentrations of aluminum and iron, respectively that will further challenge vitrification processing. Glass formulation testing also demonstrated that high waste loadings could be achieved with these tank compositions using the attributes afforded by the CCIM technology.« less

Sensor placement in nuclear reactors based on the generalized empirical interpolation method

NASA Astrophysics Data System (ADS)

Argaud, J.-P.; Bouriquet, B.; de Caso, F.; Gong, H.; Maday, Y.; Mula, O.

2018-06-01

In this paper, we apply the so-called generalized empirical interpolation method (GEIM) to address the problem of sensor placement in nuclear reactors. This task is challenging due to the accumulation of a number of difficulties like the complexity of the underlying physics and the constraints in the admissible sensor locations and their number. As a result, the placement, still today, strongly relies on the know-how and experience of engineers from different areas of expertise. The present methodology contributes to making this process become more systematic and, in turn, simplify and accelerate the procedure.

Lunar Dust 101

NASA Technical Reports Server (NTRS)

Gaier, James R.

2008-01-01

Largely due to rock and soil samples returned during the Apollo program, much has been learned about the composition and properties of lunar regolith. Although, for the most part, the mineral composition resembles terrestrial minerals, the characteristics of the lunar environment have led to very different weathering processes. These result in substantial differences in the particle shapes, particle size distributions, and surface chemistry. These differences lead to non-intuitive adhesion, abrasion, and possible health properties that will pose challenges to future lunar missions. An overview of lunar dust composition and properties will be given with a particular emphasis on possible health effects.

Light sheet microscopy.

PubMed

Weber, Michael; Mickoleit, Michaela; Huisken, Jan

2014-01-01

This chapter introduces the concept of light sheet microscopy along with practical advice on how to design and build such an instrument. Selective plane illumination microscopy is presented as an alternative to confocal microscopy due to several superior features such as high-speed full-frame acquisition, minimal phototoxicity, and multiview sample rotation. Based on our experience over the last 10 years, we summarize the key concepts in light sheet microscopy, typical implementations, and successful applications. In particular, sample mounting for long time-lapse imaging and the resulting challenges in data processing are discussed in detail. © 2014 Elsevier Inc. All rights reserved.

Health issues amongst call center employees, an emerging occupational group in India.

PubMed

Raja, Jeyapal Dinesh; Bhasin, Sanjiv Kumar

2014-07-01

Call center sector in India is a relatively new industry and one of the fastest growing sectors driving employment and growth in modern India today. While employment in the business process outsourcing (BPO) sector has meant that young adults are reaching their career milestones and financial goals much earlier than before, surveys and anecdotal evidence show that workers in the BPO sector experience high levels of stress and its related disorders, primarily due to its contemporary work settings. Safeguarding the health of youngsters employed in this new, growing economy becomes an occupational health challenge to public health specialists.

Natural products as reservoirs of novel therapeutic agents.

PubMed

Mushtaq, Sadaf; Abbasi, Bilal Haider; Uzair, Bushra; Abbasi, Rashda

2018-01-01

Since ancient times, natural products from plants, animals, microbial and marine sources have been exploited for treatment of several diseases. The knowledge of our ancestors is the base of modern drug discovery process. However, due to the presence of extensive biodiversity in natural sources, the percentage of secondary metabolites screened for bioactivity is low. This review aims to provide a brief overview of historically significant natural therapeutic agents along with some current potential drug candidates. It will also provide an insight into pros and cons of natural product discovery and how development of recent approaches has answered the challenges associated with it.

Comparing interpolation techniques for annual temperature mapping across Xinjiang region

NASA Astrophysics Data System (ADS)

Ren-ping, Zhang; Jing, Guo; Tian-gang, Liang; Qi-sheng, Feng; Aimaiti, Yusupujiang

2016-11-01

Interpolating climatic variables such as temperature is challenging due to the highly variable nature of meteorological processes and the difficulty in establishing a representative network of stations. In this paper, based on the monthly temperature data which obtained from the 154 official meteorological stations in the Xinjiang region and surrounding areas, we compared five spatial interpolation techniques: Inverse distance weighting (IDW), Ordinary kriging, Cokriging, thin-plate smoothing splines (ANUSPLIN) and Empirical Bayesian kriging(EBK). Error metrics were used to validate interpolations against independent data. Results indicated that, the ANUSPLIN performed best than the other four interpolation methods.

Development of a passive phase separator for space and earth applications

PubMed Central

Wu, Xiongjun; Loraine, Greg; Hsiao, Chao-Tsung; Chahine, Georges L.

2018-01-01

The limited amount of liquids and gases that can be carried to space makes it imperative to recycle and reuse these fluids for extended human operations. During recycling processes gas and liquid phases are often intermixed. In the absence of gravity, separating gases from liquids is challenging due to the absence of buoyancy. This paper describes development of a passive phase separator that is capable of efficiently and reliably separating gas–liquid mixtures of both high and low void fractions in a wide range of flow rates that is applicable to for both space and earth applications. PMID:29628785

Care of older people in migration contexts: local and transnational arrangements between Peru and Spain.

PubMed

Gorfinkiel, Magdalena Díaz; Escrivá, Ángeles

2012-01-01

Care arrangements for the elderly are becoming a main social process in contemporary societies due to socio-political and lifestyle changes over the last few decades. The family and the State play a basic role in the construction of care systems and in the establishment of strategies to access care resources. In the present context of migration, these resources interact at a transnational level, challenging family and State migratory regimes. These new realities need the recognition of basic international social rights, as the experiences of Peruvians living in a migration context in Spain show.

Real-time elucidation of catalytic pathways in CO hydrogenation on Ru

DOE PAGES

LaRue, Jerry; Krejci, Ondrej; Yu, Liang; ...

2017-07-31

Here, the direct elucidation of the reaction pathways in heterogeneous catalysis has been challenging due the short-lived nature of reaction intermediates. Here, we directly measured on ultrafast timescales the initial hydrogenation steps of adsorbed CO on a Ru catalyst surface, which is known as the bottleneck reaction in syngas and CO 2 reforming processes. We initiated the hydrogenation of CO with an ultrafast laser temperature jump and probed transient changes in the electronic structure using real-time x-ray spectroscopy. In combination with theoretical simulations, we verified the formation of CHO during CO hydrogenation.

Nanoparticle photoresist studies for EUV lithography

NASA Astrophysics Data System (ADS)

Kasahara, Kazuki; Xu, Hong; Kosma, Vasiliki; Odent, Jeremy; Giannelis, Emmanuel P.; Ober, Christopher K.

2017-03-01

EUV (extreme ultraviolet) lithography is one of the most promising candidates for next generation lithography. The main challenge for EUV resists is to simultaneously satisfy resolution, LWR (line-width roughness) and sensitivity requirements according to the ITRS roadmap. Though polymer type CAR (chemically amplified resist) is the currently standard photoresist, entirely new resist platforms are required due to the performance targets of smaller process nodes. In this paper, recent progress in nanoparticle photoresists which Cornell University has intensely studied is discussed. Lithography performance, especially scum elimination, improvement studies with the dissolution rate acceleration concept and new metal core applications are described.

Performance of a Lexical and POS Tagger for Sanskrit

NASA Astrophysics Data System (ADS)

Hellwig, Oliver

Due to the phonetic, morphological, and lexical complexity of Sanskrit, the automatic analysis of this language is a real challenge in the area of natural language processing. The paper describes a series of tests that were performed to assess the accuracy of the tagging program SanskritTagger. To our knowlegde, it offers the first reliable benchmark data for evaluating the quality of taggers for Sanskrit using an unrestricted dictionary and texts from different domains. Based on a detailed analysis of the test results, the paper points out possible directions for future improvements of statistical tagging procedures for Sanskrit.

[Judicial institutions of medical experts].

PubMed

Godoy, Roberto Lm

2016-05-01

This article considers the evolutive process that judicial organisms of medical experts have experienced in Argentina since their creation and formulates a proposal for its adequacy and modernization. Due to multiple and various evolutive factors, judicial organisms managing medicolegal expert activities show, nowadays, signals that a structural and dynamic reform is needed. They remain as organizational units of Public Administration and their effectiveness and efficiency depends not only of a scientific criteria but a managing one. The present and future challenge will be their conceptual transformation, from "corporate scientific entities" to "public-service-providing units" within the justice administration system.

On the Nature of Part-Time Radio Pulsars

NASA Astrophysics Data System (ADS)

Li, Xiang-Dong

2006-08-01

The recent discovery of rotating radio transients and the quasi-periodicity of pulsar activity in the radio pulsar PSR B1931+24 has challenged the conventional theory of radio pulsar emission. Here we suggest that these phenomena could be due to the interaction between the neutron star magnetosphere and the surrounding debris disk. The pattern of pulsar emission depends on whether the disk can penetrate the light cylinder and efficiently quench the processes of particle production and acceleration inside the magnetospheric gap. A precessing disk may naturally account for the switch-on/off behavior in PSR B1931+24.

Microbial Cellulases and Their Industrial Applications

PubMed Central

Kuhad, Ramesh Chander; Gupta, Rishi; Singh, Ajay

2011-01-01

Microbial cellulases have shown their potential application in various industries including pulp and paper, textile, laundry, biofuel production, food and feed industry, brewing, and agriculture. Due to the complexity of enzyme system and immense industrial potential, cellulases have been a potential candidate for research by both the academic and industrial research groups. Nowadays, significant attentions have been devoted to the current knowledge of cellulase production and the challenges in cellulase research especially in the direction of improving the process economics of various industries. Scientific and technological developments and the future prospects for application of cellulases in different industries are discussed in this paper. PMID:21912738

Modular open RF architecture: extending VICTORY to RF systems

NASA Astrophysics Data System (ADS)

Melber, Adam; Dirner, Jason; Johnson, Michael

2015-05-01

Radio frequency products spanning multiple functions have become increasingly critical to the warfighter. Military use of the electromagnetic spectrum now includes communications, electronic warfare (EW), intelligence, and mission command systems. Due to the urgent needs of counterinsurgency operations, various quick reaction capabilities (QRCs) have been fielded to enhance warfighter capability. Although these QRCs were highly successfully in their respective missions, they were designed independently resulting in significant challenges when integrated on a common platform. This paper discusses how the Modular Open RF Architecture (MORA) addresses these challenges by defining an open architecture for multifunction missions that decomposes monolithic radio systems into high-level components with welldefined functions and interfaces. The functional decomposition maximizes hardware sharing while minimizing added complexity and cost due to modularization. MORA achieves significant size, weight and power (SWaP) savings by allowing hardware such as power amplifiers and antennas to be shared across systems. By separating signal conditioning from the processing that implements the actual radio application, MORA exposes previously inaccessible architecture points, providing system integrators with the flexibility to insert third-party capabilities to address technical challenges and emerging requirements. MORA leverages the Vehicular Integration for Command, Control, Communication, Computers, Intelligence, Surveillance, and Reconnaissance (C4ISR)/EW Interoperability (VICTORY) framework. This paper concludes by discussing how MORA, VICTORY and other standards such as OpenVPX are being leveraged by the U.S. Army Research, Development, and Engineering Command (RDECOM) Communications Electronics Research, Development, and Engineering Center (CERDEC) to define a converged architecture enabling rapid technology insertion, interoperability and reduced SWaP.

Way Forward for High Performance Payload Processing Development

NASA Astrophysics Data System (ADS)

Notebaert, Olivier; Franklin, John; Lefftz, Vincent; Moreno, Jose; Patte, Mathieu; Syed, Mohsin; Wagner, Arnaud

2012-08-01

Payload processing is facing technological challenges due to the large increase of performance requirements of future scientific, observation and telecom missions as well as the future instruments technologies capturing much larger amount of data. For several years, with the perspective of higher performance together with the planned obsolescence of solutions covering the current needs, ESA and the European space industry has been developing several technology solutions. Silicon technologies, radiation mitigation techniques and innovative functional architectures are developed with the goal of designing future space qualified processing devices with a much higher level of performance than today. The fast growing commercial market application have developed very attractive technologies but which are not fully suitable with respect to their tolerance to space environment. Without the financial capacity to explore and develop all possible technology paths, a specific and global approach is required to cover the future mission needs and their necessary performance targets with effectiveness.The next sections describe main issues and priorities and provides further detailed relevant for this approach covering the high performance processing technology.

Novel technologies for reverse osmosis concentrate treatment: a review.

PubMed

Joo, Sung Hee; Tansel, Berrin

2015-03-01

Global water shortages due to droughts and population growth have created increasing interest in water reuse and recycling and, concomitantly, development of effective water treatment processes. Pressured membrane processes, in particular reverse osmosis, have been adopted in water treatment industries and utilities despite the relatively high operational cost and energy consumption. However, emerging contaminants are present in reverse osmosis concentrate in higher concentrations than in the feed water, and have created challenges for treatment of the concentrate. Further, standards and guidelines for assessment and treatment of newly identified contaminants are currently lacking. Research is needed regarding the treatment and disposal of emerging contaminants of concern in reverse osmosis concentrate, in order to develop cost-effective methods for minimizing potential impacts on public health and the environment. This paper reviews treatment options for concentrate from membrane processes. Barriers to emerging treatment options are discussed and novel treatment processes are evaluated based on a literature review. Copyright © 2014 Elsevier Ltd. All rights reserved.

Distinct neural substrates for semantic knowledge and naming in the temporoparietal network.

PubMed

Gesierich, Benno; Jovicich, Jorge; Riello, Marianna; Adriani, Michela; Monti, Alessia; Brentari, Valentina; Robinson, Simon D; Wilson, Stephen M; Fairhall, Scott L; Gorno-Tempini, Maria Luisa

2012-10-01

Patients with anterior temporal lobe (ATL) lesions show semantic and lexical retrieval deficits, and the differential role of this area in the 2 processes is debated. Functional neuroimaging in healthy individuals has not clarified the matter because semantic and lexical processes usually occur simultaneously and automatically. Furthermore, the ATL is a region challenging for functional magnetic resonance imaging (fMRI) due to susceptibility artifacts, especially at high fields. In this study, we established an optimized ATL-sensitive fMRI acquisition protocol at 4 T and applied an event-related paradigm to study the identification (i.e., association of semantic biographical information) of celebrities, with and without the ability to retrieve their proper names. While semantic processing reliably activated the ATL, only more posterior areas in the left temporal and temporal-parietal junction were significantly modulated by covert lexical retrieval. These results suggest that within a temporoparietal network, the ATL is relatively more important for semantic processing, and posterior language regions are relatively more important for lexical retrieval.

A survey of GPU-based medical image computing techniques

PubMed Central

Shi, Lin; Liu, Wen; Zhang, Heye; Xie, Yongming

2012-01-01

Medical imaging currently plays a crucial role throughout the entire clinical applications from medical scientific research to diagnostics and treatment planning. However, medical imaging procedures are often computationally demanding due to the large three-dimensional (3D) medical datasets to process in practical clinical applications. With the rapidly enhancing performances of graphics processors, improved programming support, and excellent price-to-performance ratio, the graphics processing unit (GPU) has emerged as a competitive parallel computing platform for computationally expensive and demanding tasks in a wide range of medical image applications. The major purpose of this survey is to provide a comprehensive reference source for the starters or researchers involved in GPU-based medical image processing. Within this survey, the continuous advancement of GPU computing is reviewed and the existing traditional applications in three areas of medical image processing, namely, segmentation, registration and visualization, are surveyed. The potential advantages and associated challenges of current GPU-based medical imaging are also discussed to inspire future applications in medicine. PMID:23256080

High-Throughput Printing Process for Flexible Electronics

NASA Astrophysics Data System (ADS)

Hyun, Woo Jin

Printed electronics is an emerging field for manufacturing electronic devices with low cost and minimal material waste for a variety of applications including displays, distributed sensing, smart packaging, and energy management. Moreover, its compatibility with roll-to-roll production formats and flexible substrates is desirable for continuous, high-throughput production of flexible electronics. Despite the promise, however, the roll-to-roll production of printed electronics is quite challenging due to web movement hindering accurate ink registration and high-fidelity printing. In this talk, I will present a promising strategy for roll-to-roll production using a novel printing process that we term SCALE (Self-aligned Capillarity-Assisted Lithography for Electronics). By utilizing capillarity of liquid inks on nano/micro-structured substrates, the SCALE process facilitates high-resolution and self-aligned patterning of electrically functional inks with greatly improved printing tolerance. I will show the fabrication of key building blocks (e.g. transistor, resistor, capacitor) for electronic circuits using the SCALE process on plastics.

Real-time spectral characterization of a photon pair source using a chirped supercontinuum seed.

PubMed

Erskine, Jennifer; England, Duncan; Kupchak, Connor; Sussman, Benjamin

2018-02-15

Photon pair sources have wide ranging applications in a variety of quantum photonic experiments and protocols. Many of these protocols require well controlled spectral correlations between the two output photons. However, due to low cross-sections, measuring the joint spectral properties of photon pair sources has historically been a challenging and time-consuming task. Here, we present an approach for the real-time measurement of the joint spectral properties of a fiber-based four wave mixing source. We seed the four wave mixing process using a broadband chirped pulse, studying the stimulated process to extract information regarding the spontaneous process. In addition, we compare stimulated emission measurements with the spontaneous process to confirm the technique's validity. Joint spectral measurements have taken many hours historically and several minutes with recent techniques. Here, measurements have been demonstrated in 5-30 s depending on resolution, offering substantial improvement. Additional benefits of this approach include flexible resolution, large measurement bandwidth, and reduced experimental overhead.

SAGE II Measurements of Stratospheric Aerosol Properties at Non-Volcanic Levels

NASA Technical Reports Server (NTRS)

Thomason, Larry W.; Burton, Sharon P.; Luo, Bei-Ping; Peter, Thomas

2008-01-01

Since 2000, stratospheric aerosol levels have been relatively stable and at the lowest levels observed in the historical record. Given the challenges of making satellite measurements of aerosol properties at these levels, we have performed a study of the sensitivity of the product to the major components of the processing algorithm used in the production of SAGE II aerosol extinction measurements and the retrieval process that produces the operational surface area density (SAD) product. We find that the aerosol extinction measurements, particularly at 1020 nm, remain robust and reliable at the observed aerosol levels. On the other hand, during background periods, the SAD operational product has an uncertainty of at least a factor of 2 during due to the lack of sensitivity to particles with radii less than 100 nm.

Reducing Sodium in Foods: The Effect on Flavor

PubMed Central

Liem, Djin Gie; Miremadi, Fatemeh; Keast, Russell S. J.

2011-01-01

Sodium is an essential micronutrient and, via salt taste, appetitive. High consumption of sodium is, however, related to negative health effects such as hypertension, cardiovascular diseases and stroke. In industrialized countries, about 75% of sodium in the diet comes from manufactured foods and foods eaten away from home. Reducing sodium in processed foods will be, however, challenging due to sodium’s specific functionality in terms of flavor and associated palatability of foods (i.e., increase of saltiness, reduction of bitterness, enhancement of sweetness and other congruent flavors). The current review discusses the sensory role of sodium in food, determinants of salt taste perception and a variety of strategies, such as sodium replacers (i.e., potassium salts) and gradual reduction of sodium, to decrease sodium in processed foods while maintaining palatability. PMID:22254117

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.