The adaptive, cut-cell Cartesian approach (warts and all)

NASA Technical Reports Server (NTRS)

Powell, Kenneth G.

1995-01-01

Solution-adaptive methods based on cutting bodies out of Cartesian grids are gaining popularity now that the ways of circumventing the accuracy problems associated with small cut cells have been developed. Researchers are applying Cartesian-based schemes to a broad class of problems now, and, although there is still development work to be done, it is becoming clearer which problems are best suited to the approach (and which are not). The purpose of this paper is to give a candid assessment, based on applying Cartesian schemes to a variety of problems, of the strengths and weaknesses of the approach as it is currently implemented.

Space Photovoltaic Research and Technology 1986. High Efficiency, Space Environment, and Array Technology

NASA Technical Reports Server (NTRS)

1987-01-01

The conference provided a forum to assess the progress made, the problems remaining, and the strategy for the future of photovoltaic research. Cell research and technology, space environmental effects, array technology and applications were discussed.

Normal Untreated Jurkat Cells

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions. These Jurkat cells, a human acute T-cell leukemia was obtained to evaluate three types of potential experimental stressors: a) Temperature elevation; b) Serum starvation; and c) Centrifugal force. The data from previous spaceflight experiments showed that actin filaments and cell shape are significantly different for the control. These normal cells serve as the baseline for future spaceflight experiments.

Stem cell research: applicability in dentistry.

PubMed

Mathur, Shivani; Chopra, Rahul; Pandit, I K; Srivastava, Nikhil; Gugnani, Neeraj

2014-01-01

In the face of extraordinary advances in the prevention, diagnosis, and treatment of human diseases, the inability of most tissues and organs to repair and regenerate after damage is a problem that needs to be solved. Stem cell research is being pursued in the hope of achieving major medical breakthroughs. Scientists are striving to create therapies that rebuild or replace damaged cells with tissues grown from stem cells that will offer hope to people suffering from various ailments. Regeneration of damaged periodontal tissue, bone, pulp, and dentin is a problem that dentists face today. Stem cells present in dental pulp, periodontal ligament, and alveolar bone marrow have the potential to repair and regenerate teeth and periodontal structures. These stem cells can be harvested from dental pulp, periodontal ligament, and/or alveolar bone marrow; expanded; embedded in an appropriate scaffold; and transplanted back into a defect to regenerate bone and tooth structures. These cells have the potential to regenerate dentin, periodontal ligament, and cementum and can also be used to restore bone defects. The kind of scaffold, the source of cells, the type of in vitro culturing, and the type of surgical procedure to be used all require careful consideration. The endeavor is clearly multidisciplinary in nature, and the practicing dental surgeon has a critical role in it. Playing this role in the most effective way requires awareness of the huge potential associated with the use of stem cells in a clinical setting, as well as a proper understanding of the related problems.

From iPSC towards cardiac tissue-a road under construction.

PubMed

Peischard, Stefan; Piccini, Ilaria; Strutz-Seebohm, Nathalie; Greber, Boris; Seebohm, Guiscard

2017-10-01

The possibility to generate induced pluripotent stem cells (iPSC) opens the way to generate virtually all cell types of our human body. In combination with modern gene editing techniques like CRISPR/CAS, a new set of powerful tools becomes available for life science. Scientific fields like genotype and cell type-specific pharmacology, disease modeling, stem cell biology, and developmental biology have been dramatically fostered and their faces have been changed. However, as golden as the age of iPSC-derived cells and their manipulation has started, the shine begins to tarnish. Researchers face more and more practical problems intrinsic to the system. These problems are related to the specific culturing conditions which are not yet sufficient to mimic the natural environment of native stem cells differentiating towards adult cells. However, researchers work hard to uncover these factors. Here, we review a common standard approach to generate iPSCs and transduce these to iPSC cardiomyocytes. Further, we review recent achievements and discuss their current limitations and future perspectives. We are on track, but the road is still under construction.

Biotechnology Apprenticeship for Secondary-Level Students: Teaching Advanced Cell Culture Techniques for Research.

ERIC Educational Resources Information Center

Lewis, Jennifer R.; Kotur, Mark S.; Butt, Omar; Kulcarni, Sumant; Riley, Alyssa A.; Ferrell, Nick; Sullivan, Kathryn D.; Ferrari, Mauro

2002-01-01

Discusses small-group apprenticeships (SGAs) as a method for introducing cell culture techniques to high school participants. Teaches cell culture practices and introduces advance imaging techniques to solve various biomedical engineering problems. Clarifies and illuminates the value of small-group laboratory apprenticeships. (Author/KHR)

Research, development and demonstration of lead-acid batteries for electric vehicle propulsion

NASA Astrophysics Data System (ADS)

Bowman, D. E.

1983-08-01

Research programs on lead-acid batteries are reported that cover active materials utilization, active material integrity, and some technical support projects. Processing problems were encountered and corrected. Components and materials, a lead-plastic composite grid, cell designs, and deliverables are described. Cell testing is discussed, as well as battery subsystems, including fuel gage, thermal management, and electrolyte circulation.

[Advances in microbial solar cells--A review].

PubMed

Guo, Xiaoyun; Yu, Changping; Zheng, Tianling

2015-08-04

The energy crisis has become one of the major problems hindering the development of the world. The emergence of microbial fuel cells provides a new solution to the energy crisis. Microbial solar cells, integrating photosynthetic organisms such as plants and microalgae into microbial fuel cells, can convert solar energy into electrical energy. Microbial solar cell has steady electric energy, and broad application prospects in wastewater treatment, biodiesel processing and intermediate metabolites production. Here we reviewed recent progress of microbial solar cells from the perspective of the role of photosynthetic organisms in microbial fuel cells, based on a vast amount of literature, and discussed their advantages and deficiency. At last, brief analysis of the facing problems and research needs of microbial fuel cells are undertaken. This work was expected to be beneficial for the application of the microbial solar cells technology.

Cell separation: Terminology and practical considerations

PubMed Central

Tomlinson, Sophie; Yang, Xuebin B; Kirkham, Jennifer

2013-01-01

Cell separation is a powerful tool in biological research. Increasing usage, particularly within the tissue engineering and regenerative medicine communities, means that researchers from a diverse range of backgrounds are utilising cell separation technologies. This review aims to offer potential solutions to cell sorting problems and to clarify common ambiguities in terminology and experimental design. The frequently used cell separation terms of ‘purity’, ‘recovery’ and ‘viability’ are discussed, and attempts are made to reach a consensus view of their sometimes ambiguous meanings. The importance of appropriate experimental design is considered, with aspects such as marker expression, tissue isolation and original cell population analysis discussed. Finally, specific technical issues such as cell clustering, dead cell removal and non-specific antibody binding are considered and potential solutions offered. The solutions offered may provide a starting point to improve the quality of cell separations achieved by both the novice and experienced researcher alike. PMID:23440031

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions. These Jurkat cells, a human acute T-cell leukemia was obtained to evaluate three types of potential experimental stressors: a) Temperature elevation; b) Serum starvation; and c) Centrifugal force. The data from previous spaceflight experiments showed that actin filaments and cell shape are significantly different for the control. These normal cells serve as the baseline for future spaceflight experiments.

Biotechnology Apprenticeship for Secondary-Level Students: Teaching Advanced Cell Culture Techniques for Research

ERIC Educational Resources Information Center

Lewis, Jennifer R.; Kotur, Mark S.; Butt, Omar; Kulcarni, Sumant; Riley, Alyssa A.; Ferrell, Nick; Sullivan, Kathryn D.; Ferrari, Mauro

2002-01-01

The purpose of this article is to discuss "small-group apprenticeships (SGAs)" as a method to instruct cell culture techniques to high school participants. The study aimed to teach cell culture practices and to introduce advanced imaging techniques to solve various biomedical engineering problems. Participants designed and completed experiments…

Machine Learning Approach to Automated Quality Identification of Human Induced Pluripotent Stem Cell Colony Images.

PubMed

Joutsijoki, Henry; Haponen, Markus; Rasku, Jyrki; Aalto-Setälä, Katriina; Juhola, Martti

2016-01-01

The focus of this research is on automated identification of the quality of human induced pluripotent stem cell (iPSC) colony images. iPS cell technology is a contemporary method by which the patient's cells are reprogrammed back to stem cells and are differentiated to any cell type wanted. iPS cell technology will be used in future to patient specific drug screening, disease modeling, and tissue repairing, for instance. However, there are technical challenges before iPS cell technology can be used in practice and one of them is quality control of growing iPSC colonies which is currently done manually but is unfeasible solution in large-scale cultures. The monitoring problem returns to image analysis and classification problem. In this paper, we tackle this problem using machine learning methods such as multiclass Support Vector Machines and several baseline methods together with Scaled Invariant Feature Transformation based features. We perform over 80 test arrangements and do a thorough parameter value search. The best accuracy (62.4%) for classification was obtained by using a k-NN classifier showing improved accuracy compared to earlier studies.

The August Krogh principle applies to plants

NASA Technical Reports Server (NTRS)

Wayne, R.; Staves, M. P.

1996-01-01

The Krogh principle refers to the use of a large number of animals to study the large number of physiological problems, rather than limiting study to a particular organism for all problems. There may be organisms that are more suited to study of a particular problem than others. This same principle applies to plants. The authors are concerned with the recent trend in plant biology of using Arabidopsis thaliana as the "organism of choice." Arabidopsis is an excellent organism for molecular genetic research, but other plants are superior models for other research areas of plant biology. The authors present examples of the successful use of the Krogh principle in plant cell biology research, emphasizing the particular characteristics of the selected research organisms that make them the appropriate choice.

Personalized targeted therapy for esophageal squamous cell carcinoma

PubMed Central

Kang, Xiaozheng; Chen, Keneng; Li, Yicheng; Li, Jianying; D'Amico, Thomas A; Chen, Xiaoxin

2015-01-01

Esophageal squamous cell carcinoma continues to heavily burden clinicians worldwide. Researchers have discovered the genomic landscape of esophageal squamous cell carcinoma, which holds promise for an era of personalized oncology care. One of the most pressing problems facing this issue is to improve the understanding of the newly available genomic data, and identify the driver-gene mutations, pathways, and networks. The emergence of a legion of novel targeted agents has generated much hope and hype regarding more potent treatment regimens, but the accuracy of drug selection is still arguable. Other problems, such as cancer heterogeneity, drug resistance, exceptional responders, and side effects, have to be surmounted. Evolving topics in personalized oncology, such as interpretation of genomics data, issues in targeted therapy, research approaches for targeted therapy, and future perspectives, will be discussed in this editorial. PMID:26167067

Cancer Cell Biology: A Student-Centered Instructional Module Exploring the Use of Multimedia to Enrich Interactive, Constructivist Learning of Science

PubMed Central

Bockholt, Susanne M.; West, J. Paige; Bollenbacher, Walter E.

2003-01-01

Multimedia has the potential of providing bioscience education novel learning environments and pedagogy applications to foster student interest, involve students in the research process, advance critical thinking/problem-solving skills, and develop conceptual understanding of biological topics. Cancer Cell Biology, an interactive, multimedia, problem-based module, focuses on how mutations in protooncogenes and tumor suppressor genes can lead to uncontrolled cell proliferation by engaging students as research scientists/physicians with the task of diagnosing the molecular basis of tumor growth for a group of patients. The process of constructing the module, which was guided by scientist and student feedback/responses, is described. The completed module and insights gained from its development are presented as a potential “multimedia pedagogy” for the development of other multimedia science learning environments. PMID:12822037

World Stem Cell Summit 2014. 3-5 December 2014, San Antonio, TX, USA.

PubMed

Hasegawa, Kouichi; Asada, Takashi; Sengoku, Shintaro; Nakatsuji, Norio

2015-05-01

Among the many international conferences in the field of stem cells and regenerative medicine, WSCS is distinct in focusing its efforts to serve as the meeting point by multisector communities of research, clinics, industry, regulation, policy making and ethics. All are aiming at advancing stem cell innovation and new therapies, under the banner of 'connect, collaborate and cure'. As same as past years, presenters and attendees included not only researchers but also clinicians, funding agencies, government officials, industries and patients. Thus, many sessions focused on the clinical translation from basic research. Another important agenda were industrial and social aspects, and problems to be solved before realization of practical and sustainable stem cell-based therapies.

Biomedical research publications: 1980 - 1982

NASA Technical Reports Server (NTRS)

Pleasant, L. G.; Limbach, L.

1982-01-01

Publications concerning the major physiological and psychological problems encountered by man when he undertakes space flight are listed. Nine research areas are included: cardiovascular deconditioning, motion sickness, bone alterations, muscle atrophy, blood cell alterations, fluid and eletrolyte changes, radiation effects and protection, behavior and performance, and general biomedical research.

Cell Source and Mechanism of Hair Cell Regeneration in the Neonatal Mouse Cochlea

DTIC Science & Technology

2015-09-30

indicating that the neonatal mouse cochlea can, to a limited ex tent. pro liferate in response to HC loss and th at some of these RESEARCH ARTICLE Atoh1...cations for other tetracycline-inducible mouse models used in inner ear research . Our studies also highlight potential problems with long term expression... studies for the 10% HC death model are underway. Further research is in progress to obtain a tamoxifen induction paradigm that will target 25% ofHCs

INVESTIGATION OF THE PERSISTENCE AND REPLICATION OF NUCLEAR POLYHEDROSIS VIRUSES IN VERTEBRATE AND INSECT CELL CULTURES BY THE USE OF HYBRIDIZATION TECHNIQUES

EPA Science Inventory

The Health Effects Research Laboratory, Research Triangle Park, conducts a coordinaged environmental health research program in toxicology, epidemiology, and clinical studies using human volunteer subjects. These studies address problems in air pollution, non-ionizing radiation, ...

Challenges of primate embryonic stem cell research.

PubMed

Bavister, Barry D; Wolf, Don P; Brenner, Carol A

2005-01-01

Embryonic stem (ES) cells hold great promise for treating degenerative diseases, including diabetes, Parkinson's, Alzheimer's, neural degeneration, and cardiomyopathies. This research is controversial to some because producing ES cells requires destroying embryos, which generally means human embryos. However, some of the surplus human embryos available from in vitro fertilization (IVF) clinics may have a high rate of genetic errors and therefore would be unsuitable for ES cell research. Although gross chromosome errors can readily be detected in ES cells, other anomalies such as mitochondrial DNA defects may have gone unrecognized. An insurmountable problem is that there are no human ES cells derived from in vivo-produced embryos to provide normal comparative data. In contrast, some monkey ES cell lines have been produced using in vivo-generated, normal embryos obtained from fertile animals; these can represent a "gold standard" for primate ES cells. In this review, we argue a need for strong research programs using rhesus monkey ES cells, conducted in parallel with studies on human ES and adult stem cells, to derive the maximum information about the biology of normal stem cells and to produce technical protocols for their directed differentiation into safe and functional replacement cells, tissues, and organs. In contrast, ES cell research using only human cell lines is likely to be incomplete, which could hinder research progress, and delay or diminish the effective application of ES cell technology to the treatment of human diseases.

Nanosilver microalgae biosynthesis: cell appearance based on SEM and EDX methods

NASA Astrophysics Data System (ADS)

Pancasakti Kusumaningrum, Hermin; Zainuri, Muhammad; Marhaendrajaya, Indras; Subagio, Agus

2018-05-01

Microbial contamination has caused public health problems in the world population. This problem has spurred the development of methods to overcome and prevent microbial invasion. The extensive use of antibiotics has facilitated the continued emergence and spread of resistant organisms. Synthesized of silver nanoparticle (AgNPs) on microalgae Chlorella pyrenoidosa offer environmentally safe antimicrobial agent. The present study is focused on the biosynthesis of AgNPs using microalgae C. pyrenoidosa. The research methods was conducted by insertion of nanosilver particle into microalgae cells with and without agitation to speed up the process of formation nanosilver microalgae. The formation of microalgae SNP was analyzes by UV-Vis spectrophotometer, Scanning Electron Micrograph (SEM) and Energy-dispersive X-ray spectroscopy (EDX) methods. The research result showed that nanosilver microalgae biosynthesis using the agitation treatment was exhibited better performance in particle insertion and cell stability, comparing with no agitation treatment. However, synthesis of nanosilver microalgae tend to reduce the cell size.

Discovery of HeLa Cell Contamination in HES Cells: Call for Cell Line Authentication in Reproductive Biology Research.

PubMed

Kniss, Douglas A; Summerfield, Taryn L

2014-08-01

Continuous cell lines are used frequently in reproductive biology research to study problems in early pregnancy events and parturition. It has been recognized for 50 years that many mammalian cell lines contain inter- or intraspecies contaminations with other cells. However, most investigators do not routinely test their culture systems for cross-contamination. The most frequent contributor to cross-contamination of cell lines is the HeLa cell isolated from an aggressive cervical adenocarcinoma. We report on the discovery of HeLa cell contamination of the human endometrial epithelial cell line HES isolated in our laboratory. Short tandem repeat analysis of 9 unique genetic loci demonstrated molecular identity between HES and HeLa cells. In addition, we verified that WISH cells, isolated originally from human amnion epithelium, were also contaminated with HeLa cells. Inasmuch as our laboratory did not culture HeLa cells at the time of HES cell derivations, the source of contamination was the WISH cell line. These data highlight the need for continued diligence in authenticating cell lines used in reproductive biology research. © The Author(s) 2014.

The Promising Applications of Stem Cells in the Oral Region: Literature Review

PubMed Central

Silva, Luciano Barreto; Neto, Alexandrino Pereira Dos Santos; Pacheco, Rachel Gomes Pelozo; Júnior, Severino Alves; de Menezes, Rebeca Ferraz; Carneiro, Vanda Sanderana Macedo; Araújo, Natália Costa; da Silveira, Marcia Maria Fonseca; de Albuquerque, Diana Santana; Gerbi, Marleny Elizabeth Marquez de Martinez; Álvares, Pamella Recco; de Arruda, José Alcides Almeida; Sobral, Ana Paula Veras

2016-01-01

Introduction: For a long time researchers have tried to find out a way to grow tissues back to the human body in order to solve transplantation problems by offering the unique opportunity to have their organs back, working properly, in search of life dignity. Literature Review: Stem cells seem to be present in many other tissues than researchers had once thought; and in some specific sites they can be easily collected, without the need of expensive interventions. The oral cavity is one of these regions where their collection can be accomplished, with plenty of accessible sites enriched with these precious cells. Aim: The aim of this literature review is to research where in the mouth can scientists find stem cells to be used in the near future. Key-message: The aim of this literature review is to research where stem cells can be found and collected in the oral cavity. PMID:27386008

Ultra-wideband electronics, design methods, algorithms, and systems for dielectric spectroscopy of isolated B16 tumor cells in liquid medium

NASA Astrophysics Data System (ADS)

Maxwell, Erick N.

Quantifying and characterizing isolated tumor cells (ITCs) is of interest in surgical pathology and cytology for its potential to provide data for cancer staging, classification, and treatment. Although the independent prognostic significance of circulating ITCs has not been proven, their presence is gaining clinical relevance as an indicator. However, researchers have not established an optimal method for detecting ITCs. Consequently, this Ph.D. dissertation is concerned with the development and evaluation of dielectric spectroscopy as a low-cost method for cell characterization and quantification. In support of this goal, ultra-wideband (UWB), microwave pulse generator circuits, coaxial transmission line fixtures, permittivity extraction algorithms, and dielectric spectroscopy measurement systems were developed for evaluating the capacity to quantify B16-F10 tumor cells in suspension. First, this research addressed challenges in developing tunable UWB circuits for pulse generation. In time-domain dielectric spectroscopy, a tunable UWB pulse generator facilitates exploration of microscopic dielectric mechanisms, which contribute to dispersion characteristics. Conventional approaches to tunable pulse generator design have resulted in complex circuit topologies and unsymmetrical waveform morphologies. In this research, a new design approach for low-complexity, tunable, sub-nanosecond and UWB pulse generator was developed. This approach was applied to the development of a novel generator that produces symmetrical waveforms (patent pending 60/597,746). Next, this research addressed problems with transmission-reflection (T/R) measurement of cell suspensions. In T/R measurement, coaxial transmission line fixtures have historically required an elaborate sample holder for containing liquids, resulting in high cost and complexity. Furthermore, the algorithms used to extract T/R dielectric properties have suffered from myriad problems including local minima and halfwavelength resonance. In this dissertation, a simple coaxial transmission line fixture for holding liquids by dispensing with the air-core assumption inherent in previous designs was developed (patent pending 60/916,042). In addition, a genetic algorithm was applied towards extracting dielectric properties from measurement data to circumvent problems of local minima and half wavelength resonance. Finally, in this research the capacity for using dielectric properties to quantify isolated B16-F10 tumor cells in McCoy's liquid medium was investigated. In so doing, the utility of the Maxwell-Wagner mixture formula for cell quantification was demonstrated by measuring distinct dielectric properties for differing volumes of cell suspensions using frequency- and time-domain dielectric spectroscopy.

Step by Step: Biology Undergraduates' Problem-Solving Procedures during Multiple-Choice Assessment.

PubMed

Prevost, Luanna B; Lemons, Paula P

2016-01-01

This study uses the theoretical framework of domain-specific problem solving to explore the procedures students use to solve multiple-choice problems about biology concepts. We designed several multiple-choice problems and administered them on four exams. We trained students to produce written descriptions of how they solved the problem, and this allowed us to systematically investigate their problem-solving procedures. We identified a range of procedures and organized them as domain general, domain specific, or hybrid. We also identified domain-general and domain-specific errors made by students during problem solving. We found that students use domain-general and hybrid procedures more frequently when solving lower-order problems than higher-order problems, while they use domain-specific procedures more frequently when solving higher-order problems. Additionally, the more domain-specific procedures students used, the higher the likelihood that they would answer the problem correctly, up to five procedures. However, if students used just one domain-general procedure, they were as likely to answer the problem correctly as if they had used two to five domain-general procedures. Our findings provide a categorization scheme and framework for additional research on biology problem solving and suggest several important implications for researchers and instructors. © 2016 L. B. Prevost and P. P. Lemons. CBE—Life Sciences Education © 2016 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

The use of human cells in biomedical research and testing.

PubMed

Combes, Robert D

2004-06-01

The ability to use human cells in biomedical research and testing has the obvious advantage over the use of laboratory animals that the need for species extrapolation is obviated, due to the presence of more-relevant morphological, physiological and biochemical properties, including receptors. Moreover, human cells exhibit the same advantages as animal cells in culture in that different cell types can be used, from different tissues, with a wide range of techniques, to investigate a wide variety of biological phenomena in tissue culture. Human cells can also be grown as organotypic cultures to facilitate the extrapolation from cells to whole organisms. Human cell lines have been available for many years on an ad hoc basis from individual researchers, and also from recognised sources, such as the European Collection of Animal Cell Cultures (ECACC) and, in the USA, the Human Cell Culture Centre (HCCC). Such cells have usually been derived from tumours and this has restricted the variety of types of cells available. This problem has been addressed by using primary human cells that can be obtained from a variety of sources, such as cadavers, diseased tissue, skin strips, peripheral blood, buccal cavity smears, hair follicles and surgical waste from biopsy material that is unsuitable for transplantation purposes. However, primary human cells need to be obtained, processed, distributed and handled in a safe and ethical manner. They also have to be made available at the correct time to researchers very shortly after they become available. It is only comparatively recently that the safe and controlled acquisition of surgical waste and non-transplantable human tissues has become feasible with the establishment of several human tissue banks. Recently, the formation of a UK and European centralised network for human tissue supply has been initiated. The problems of short longevity and loss of specialisation in culture are being approached by: a) cell immortalisation to generate a cell type possessing the properties of both primary cells and cell lines; b) the inhibition of intracellular activities resulting in oxidative stress; and c) the use of stem cells, both of embryonic and adult origin.

Students' understandings of electrochemistry

NASA Astrophysics Data System (ADS)

O'Grady-Morris, Kathryn

Electrochemistry is considered by students to be a difficult topic in chemistry. This research was a mixed methods study guided by the research question: At the end of a unit of study, what are students' understandings of electrochemistry? The framework of analysis used for the qualitative and quantitative data collected in this study was comprised of three categories: types of knowledge used in problem solving, levels of representation of knowledge in chemistry (macroscopic, symbolic, and particulate), and alternative conceptions. Although individually each of the three categories has been reported in previous studies, the contribution of this study is the inter-relationships among them. Semi-structured, task-based interviews were conducted while students were setting up and operating electrochemical cells in the laboratory, and a two-tiered, multiple-choice diagnostic instrument was designed to identify alternative conceptions that students held at the end of the unit. For familiar problems, those involving routine voltaic cells, students used a working-forwards problem-solving strategy, two or three levels of representation of knowledge during explanations, scored higher on both procedural and conceptual knowledge questions in the diagnostic instrument, and held fewer alternative conceptions related to the operation of these cells. For less familiar problems, those involving non-routine voltaic cells and electrolytic cells, students approached problem-solving with procedural knowledge, used only one level of representation of knowledge when explaining the operation of these cells, scored higher on procedural knowledge than conceptual knowledge questions in the diagnostic instrument, and held a greater number of alternative conceptions. Decision routines that involved memorized formulas and procedures were used to solve both quantitative and qualitative problems and the main source of alternative conceptions in this study was the overgeneralization of theory related to the particulate level of representation of knowledge. The findings from this study may contribute further to our understanding of students' conceptions in electrochemistry. Furthermore, understanding the influence of the three categories in the framework of analysis and their inter-relationships on how students make sense of this field may result in a better understanding of classroom practice that could promote the acquisition of conceptual knowledge --- knowledge that is "rich in relationships".

NCI 1st International Workshop on the Biology, Prevention, and Treatment of Relapse After Allogeneic Hematopoietic Stem Cell Transplantation: Summary and Recommendations from the Organizing Committee

PubMed Central

Bishop, Michael R.; Alyea, Edwin P.; Cairo, Mitchell S.; Falkenburg, J.H. Frederik; June, Carl H.; Kröger, Nicolaus; Little, Richard F.; Miller, Jeffrey S.; Pavletic, Steven Z.; Porter, David L.; Riddell, Stanley R.; van Besien, Koen; Wayne, Alan S.; Weisdorf, Daniel J.; Wu, Roy S.; Giralt, Sergio

2011-01-01

The First International Workshop on The Biology, Prevention, and Treatment of Relapse After Allogeneic Hematopoietic Stem Cell Transplantation was organized and convened to identify, prioritize, and coordinate future research activities related to relapse after allogeneic hematopoietic stem cell transplantation (alloHSCT). Each of the Workshop’s six working committees have published individual reports of ongoing basic, translational and clinical research and recommended areas for future research related to the areas of relapse biology, epidemiology, prevention and treatment. This document summarizes each of the committees’ recommendations and suggests three major initiatives for a coordinated research effort to address the problem of relapse after alloHSCT. The first is the need to establish multi-center correlative and clinical trials networks for basic/translational, epidemiological, and clinical research. Second, there is a need for a network of biorepositories for the collection of samples pre- and post-alloHSCT to aid in laboratory and clinical studies. Third, there should be further refinement, implementation, and study of the proposed Workshop disease-specific response and relapse definitions and the recommendations for monitoring of minimal residual disease. These recommendations, in coordination with ongoing research initiatives and transplant organizations, provide a research framework to rapidly and efficiently address the significant problem of relapse following alloHSCT. PMID:21224011

The procurement of cells for the derivation of human embryonic stem cell lines for therapeutic use: recommendations for good practice.

PubMed

Murdoch, Alison; Braude, Peter; Courtney, Aidan; Brison, Daniel; Hunt, Charles; Lawford-Davies, James; Moore, Harry; Stacey, Glyn; Sethe, Sebastian

2012-03-01

The donation of human embryos for the derivation of embryonic stem cell lines that may be used in the development of therapeutic products raises more complex ethical, practical and regulatory problems than the donation of embryos for non-clinical research. This review considers these issues and offers recommendations for good practice.

The role of nanotechnology in induced pluripotent and embryonic stem cells research.

PubMed

Chen, Lukui; Qiu, Rong; Li, Lushen

2014-12-01

This paper reviews the recent studies on development of nanotechnology in the field of induced pluripotent and embryonic stem cells. Stem cell therapy is a promising therapy that can improve the quality of life for patients with refractory diseases. However, this option is limited by the scarcity of tissues, ethical problem, and tumorigenicity. Nanotechnology is another promising therapy that can be used to mimic the extracellular matrix, label the implanted cells, and also can be applied in the tissue engineering. In this review, we briefly introduce implementation of nanotechnology in induced pluripotent and embryonic stem cells research. Finally, the potential application of nanotechnology in tissue engineering and regenerative medicine is also discussed.

How Can We Treat Cancer Disease Not Cancer Cells?

PubMed

Kim, Kyu-Won; Lee, Su-Jae; Kim, Woo-Young; Seo, Ji Hae; Lee, Ho-Young

2017-01-01

Since molecular biology studies began, researches in biological science have centered on proteins and genes at molecular level of a single cell. Cancer research has also focused on various functions of proteins and genes that distinguish cancer cells from normal cells. Accordingly, most contemporary anticancer drugs have been developed to target abnormal characteristics of cancer cells. Despite the great advances in the development of anticancer drugs, vast majority of patients with advanced cancer have shown grim prognosis and high rate of relapse. To resolve this problem, we must reevaluate our focuses in current cancer research. Cancer should be considered as a systemic disease because cancer cells undergo a complex interaction with various surrounding cells in cancer tissue and spread to whole body through metastasis under the control of the systemic modulation. Human body relies on the cooperative interaction between various tissues and organs, and each organ performs its specialized function through tissue-specific cell networks. Therefore, investigation of the tumor-specific cell networks can provide novel strategy to overcome the limitation of current cancer research. This review presents the limitations of the current cancer research, emphasizing the necessity of studying tissue-specific cell network which could be a new perspective on treating cancer disease, not cancer cells.

Anchorage Dependent Cells Attached to a Polymer

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Anchorage dependent cells on STS-95 will be grown on beads similar to these cells produced during previous investigations. Recombinant proteins may offer the possibility of reducing or eliminating transplant rejections. Research by Synthecon, Inc. using the BioDyn Bioreactor will focus on the preliminary process for growing a proprietary recombinant protein that can decrease rejection of transplanted tissue. The cells producing this protein are anchorage dependent, meaning that they must attach to something to grow. These cells will be cultured in the bioreactor in a medium containing polymer microbeads. Synthecon hopes that the data from this mission will lead to the development of a commercial protein that will aid in prevention of transplant rejection.

Anchorage Dependent Cells Attached to a Polymer

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Anchorage dependent cells on STS-95 will be grown on beads, similar to these cells produced during previous investigations. Recombinant proteins may offer the possibility of reducing or eliminating transplant rejections. Research by Synthecon, Inc. using the BioDyn Bioreactor will focus on the preliminary process for growing a proprietary recombinant protein that can decrease rejection of transplanted tissue. The cells producing this protein are anchorage dependent, meaning that they must attach to something to grow. These cells will be cultured in the bioreactor in a medium containing polymer microbeads. Synthecon hopes that the data from this mission will lead to the development of a commercial protein that will aid in prevention of transplant rejection.

Mechanisms of Immune Evasion in Leishmaniasis

PubMed Central

Gupta, Gaurav; Oghumu, Steve; Satoskar, Abhay R.

2013-01-01

Diseases caused by Leishmania present a worldwide problem, and current therapeutic approaches are unable to achieve a sterile cure. Leishmania is able to persist in host cells by evading or exploiting host immune mechanisms. A thorough understanding of these mechanisms could lead to better strategies for effective management of Leishmania infections. Current research has focused on parasite modification of host cell signaling pathways, entry into phagocytic cells, and modulation of cytokine and chemokine profiles that alter immune cell activation and trafficking to sites of infection. Immuno-therapeutic approaches that target these mechanisms of immune evasion by Leishmania offer promising areas for preclinical and clinical research. PMID:23415155

Cancer: A Problem of Developmental Biology; Scientific Evidence for Reprogramming and Differentiation Therapy.

PubMed

Sell, Stewart; Nicolini, Andrea; Ferrari, Paola; Biava, Pier M

2016-01-01

Current medical literature acknowledges that embryonic micro-environment is able to suppress tumor development. Administering carcinogenic substances during organogenesis in fact leads to embryonic malformations, but not to offspring tumor growth. Once organogenesis has ended, administration of carcinogenic substances causes a rise in offspring tumor development. These data indicate that cancer can be considered a deviation in normal development, which can be regulated by factors of the embryonic microenvironment. Furthermore, it has been demonstrated that teratoma differentiates into normal tissues once it is implanted in the embryo. Recently, it has been shown that implanting a melanoma in Zebrafish embryo did not result in a tumor development; however, it did in the adult specimen. This demonstrates that cancer cells can differentiate into normal tissues when implanted in the embryo. In addition, it was demonstrated that other tumors can revert into a normal phenotype and/or differentiate into normal tissue when implanted in the embryo. These studies led some authors to define cancer as a problem of developmental biology and to predict the present concept of "cancer stem cells theory". In this review, we record the most important researches about the reprogramming and differentiation treatments of cancer cells to better clarify how the substances taken from developing embryo or other biological substances can induce differentiation of malignant cells. Lastly, a model of cancer has been proposed here, conceived by one of us, which is consistent with the reality, as demonstrated by a great number of researches. This model integrates the theory of the "maturation arrest" of cancer cells as conceived by B. Pierce with the theory which describes cancer as a process of deterministic chaos determined by genetic and/or epigenetic alterations in differentiated cells, which leads a normal cell to become cancerous. All the researches here described demonstrated that cancer can be considered a problem of developmental biology and that one of the most important hallmarks of cancer is the loss of differentiation as already described by us in other articles.

UCSF Small Molecule Discovery Center: innovation, collaboration and chemical biology in the Bay Area.

PubMed

Arkin, Michelle R; Ang, Kenny K H; Chen, Steven; Davies, Julia; Merron, Connie; Tang, Yinyan; Wilson, Christopher G M; Renslo, Adam R

2014-05-01

The Small Molecule Discovery Center (SMDC) at the University of California, San Francisco, works collaboratively with the scientific community to solve challenging problems in chemical biology and drug discovery. The SMDC includes a high throughput screening facility, medicinal chemistry, and research labs focused on fundamental problems in biochemistry and targeted drug delivery. Here, we outline our HTS program and provide examples of chemical tools developed through SMDC collaborations. We have an active research program in developing quantitative cell-based screens for primary cells and whole organisms; here, we describe whole-organism screens to find drugs against parasites that cause neglected tropical diseases. We are also very interested in target-based approaches for so-called "undruggable", protein classes and fragment-based lead discovery. This expertise has led to several pharmaceutical collaborations; additionally, the SMDC works with start-up companies to enable their early-stage research. The SMDC, located in the biotech-focused Mission Bay neighborhood in San Francisco, is a hub for innovative small-molecule discovery research at UCSF.

Research and developing countries: hopes and hypes.

PubMed

Moazam, Farhat

2006-01-01

The paper outlines the universal problem of ensuring ethical practices in human subject research, and focuses on specific difficulties faced in the developing world with particular reference to Pakistan. It discusses the influence of traditional and hierarchical social norms of physician-patient relationships in heightening these problems. Two emerging issues of specific concern in Pakistan are described: an exponential rise in multinational clinical drug trials, and commercial ventures offering unproven stem cell "therapy" for all kinds of diseases. The importance of introducing ethical practices in research within the context of local cultural and socioeconomic realities is highlighted.

Vision-guided micromanipulation system for biomedical application

NASA Astrophysics Data System (ADS)

Shim, Jae-Hong; Cho, Sung-Yong; Cha, Dong-Hyuk

2004-10-01

In these days, various researches for biomedical application of robots have been carried out. Particularly, robotic manipulation of the biological cells has been studied by many researchers. Usually, most of the biological cell's shape is sphere. Commercial biological manipulation systems have been utilized the 2-Dimensional images through the optical microscopes only. Moreover, manipulation of the biological cells mainly depends on the subjective viewpoint of an operator. Due to these reasons, there exist lots of problems such as slippery and destruction of the cell membrane and damage of the pipette tip etc. In order to overcome the problems, we have proposed a vision-guided biological cell manipulation system. The newly proposed manipulation system makes use of vision and graphic techniques. Through the proposed procedures, an operator can inject the biological cell scientifically and objectively. Also, the proposed manipulation system can measure the contact force occurred at injection of a biological cell. It can be transmitted a measured force to the operator by the proposed haptic device. Consequently, the proposed manipulation system could safely handle the biological cells without any damage. This paper presents the introduction of our vision-guided manipulation techniques and the concept of the contact force sensing. Through a series of experiments the proposed vision-guided manipulation system shows the possibility of application for precision manipulation of the biological cell such as DNA.

Biotechnology Apprenticeship for Secondary-Level Students: Teaching Advanced Cell Culture Techniques for Research

PubMed Central

Lewis, Jennifer R.; Kotur, Mark S.; Butt, Omar; Kulcarni, Sumant; Riley, Alyssa A.; Ferrell, Nick; Sullivan, Kathryn D.; Ferrari, Mauro

2002-01-01

The purpose of this article is to discuss small-group apprenticeships (SGAs) as a method to instruct cell culture techniques to high school participants. The study aimed to teach cell culture practices and to introduce advanced imaging techniques to solve various biomedical engineering problems. Participants designed and completed experiments using both flow cytometry and laser scanning cytometry during the 1-month summer apprenticeship. In addition to effectively and efficiently teaching cell biology laboratory techniques, this course design provided an opportunity for research training, career exploration, and mentoring. Students participated in active research projects, working with a skilled interdisciplinary team of researchers in a large research institution with access to state-of-the-art instrumentation. The instructors, composed of graduate students, laboratory managers, and principal investigators, worked well together to present a real and worthwhile research experience. The students enjoyed learning cell culture techniques while contributing to active research projects. The institution's researchers were equally enthusiastic to instruct and serve as mentors. In this article, we clarify and illuminate the value of small-group laboratory apprenticeships to the institution and the students by presenting the results and experiences of seven middle and high school participants and their instructors. PMID:12587031

Biotechnology apprenticeship for secondary-level students: teaching advanced cell culture techniques for research.

PubMed

Lewis, Jennifer R; Kotur, Mark S; Butt, Omar; Kulcarni, Sumant; Riley, Alyssa A; Ferrell, Nick; Sullivan, Kathryn D; Ferrari, Mauro

2002-01-01

The purpose of this article is to discuss small-group apprenticeships (SGAs) as a method to instruct cell culture techniques to high school participants. The study aimed to teach cell culture practices and to introduce advanced imaging techniques to solve various biomedical engineering problems. Participants designed and completed experiments using both flow cytometry and laser scanning cytometry during the 1-month summer apprenticeship. In addition to effectively and efficiently teaching cell biology laboratory techniques, this course design provided an opportunity for research training, career exploration, and mentoring. Students participated in active research projects, working with a skilled interdisciplinary team of researchers in a large research institution with access to state-of-the-art instrumentation. The instructors, composed of graduate students, laboratory managers, and principal investigators, worked well together to present a real and worthwhile research experience. The students enjoyed learning cell culture techniques while contributing to active research projects. The institution's researchers were equally enthusiastic to instruct and serve as mentors. In this article, we clarify and illuminate the value of small-group laboratory apprenticeships to the institution and the students by presenting the results and experiences of seven middle and high school participants and their instructors.

Bone regeneration and stem cells

PubMed Central

Arvidson, K; Abdallah, B M; Applegate, L A; Baldini, N; Cenni, E; Gomez-Barrena, E; Granchi, D; Kassem, M; Konttinen, Y T; Mustafa, K; Pioletti, D P; Sillat, T; Finne-Wistrand, A

2011-01-01

Abstract This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed. PMID:21129153

Benefiting from 'evil': an incipient moral problem in human stem cell research.

PubMed

Green, Ronald M

2002-11-01

When does benefiting from others' wrongdoing effectively make one a moral accomplice in their evil deeds? If stem cell research lives up to its therapeutic promise, this question (which has previously cropped up in debates over fetal tissue research or the use of Nazi research data) is likely to become a central one for opponents of embryo destruction. I argue that benefiting from wrongdoing is prima facie morally wrong under any of three conditions: (1) when the wrongdoing is one's agent; (2) when acceptance of benefit directly encourages the repetition of the wrongful deed (even though no agency relationship is involved); and (3) when acceptance of a benefit legitimates a wrongful practice. I conclude by showing that, because of the ways in which most embryonic stem cell lines come into being, people who oppose embryo destruction may use human embryonic stem cells without incurring moral blame.

Statistical Inference-Based Cache Management for Mobile Learning

ERIC Educational Resources Information Center

Li, Qing; Zhao, Jianmin; Zhu, Xinzhong

2009-01-01

Supporting efficient data access in the mobile learning environment is becoming a hot research problem in recent years, and the problem becomes tougher when the clients are using light-weight mobile devices such as cell phones whose limited storage space prevents the clients from holding a large cache. A practical solution is to store the cache…

Induced Pluripotent Stem Cells in Huntington's Disease Research: Progress and Opportunity.

PubMed

Tousley, Adelaide; Kegel-Gleason, Kimberly B

2016-06-28

Induced pluripotent stem cells (iPSCs) derived from controls and patients can act as a starting point for in vitro differentiation into human brain cells for discovery of novel targets and treatments for human disease without the same ethical limitations posed by embryonic stem cells. Numerous groups have successfully produced and characterized Huntington's disease (HD) iPSCs with different CAG repeat lengths, including cells from patients with one or two HD alleles. HD iPSCs and the neural cell types derived from them recapitulate some disease phenotypes found in both human patients and animal models. Although these discoveries are encouraging, the use of iPSCs for cutting edge and reproducible research has been limited due to some of the inherent problems with cell lines and the technological differences in the way laboratories use them. The goal of this review is to summarize the current state of the HD iPSC field, and to highlight some of the issues that need to be addressed to maximize their potential as research tools.

[Therapeutic cloning in debate].

PubMed

de Wert, G

2001-11-03

Human embryos can be conceived by cell nuclear transfer in order to isolate human embryonic stem cells (hES cells) for research into autologous cell therapy (therapeutic cloning). However, this technique broaches the major ethical problem concerning the instrumental use of human preimplantation embryos. From the viewpoint of subsidiarity, it is argued that various potential alternatives for therapeutic cloning should first be investigated further. The question as to whether therapeutic cloning should be allowed only becomes apparent when research with surplus embryos obtained in the course of in-vitro fertilization suggests that usable transplants can be obtained in vitro from hES cells, and when the potential alternatives for therapeutic cloning are either less promising or need more time for development than is currently expected.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Anchorage dependent cells on STS-95 will be grown on beads similar to these cells produced during previous investigations. Recombinant proteins may offer the possibility of reducing or eliminating transplant rejections. Research by Synthecon, Inc. using the BioDyn Bioreactor will focus on the preliminary process for growing a proprietary recombinant protein that can decrease rejection of transplanted tissue. The cells producing this protein are anchorage dependent, meaning that they must attach to something to grow. These cells will be cultured in the bioreactor in a medium containing polymer microbeads. Synthecon hopes that the data from this mission will lead to the development of a commercial protein that will aid in prevention of transplant rejection.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Anchorage dependent cells on STS-95 will be grown on beads, similar to these cells produced during previous investigations. Recombinant proteins may offer the possibility of reducing or eliminating transplant rejections. Research by Synthecon, Inc. using the BioDyn Bioreactor will focus on the preliminary process for growing a proprietary recombinant protein that can decrease rejection of transplanted tissue. The cells producing this protein are anchorage dependent, meaning that they must attach to something to grow. These cells will be cultured in the bioreactor in a medium containing polymer microbeads. Synthecon hopes that the data from this mission will lead to the development of a commercial protein that will aid in prevention of transplant rejection.

Chemical Biodynamics Division. Annual report 1979

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

Not Available

1980-08-01

The Chemical Biodynamics Division of LBL continues to conduct basic research on the dynamics of living cells and on the interaction of radiant energy with organic matter. Many aspects of this basic research are related to problems of environmental and health effects of fossil fuel combustion, solar energy conversion and chemical/ viral carcinogenesis.

Current and emerging global themes in the bioethics of regenerative medicine: the tangled web of stem cell translation.

PubMed

Chan, Sarah

2017-10-01

Probably the most serious problem facing the field of regenerative medicine today is the challenge of effective translation and development of viable stem cell-based therapies. Particular concerns have been raised over the growing market in unproven cell therapies. In this article, I explore recent developments in the stem cell therapy landscape and argue that while the sale of unproven therapies undoubtedly poses ethical concerns, it must be understood as part of a larger problem at the interface between biomedicine, healthcare, publics, policy and the market. Addressing this will require a broader perspective incorporating the shifting relationships between different stakeholder groups, the global politics of research and innovation, and the evolving role of publics and patients with respect to science.

Cell transplantation and genetic engineering: new approaches to cardiac pathology.

PubMed

Leor, Jonathan; Barbash, Israel M

2003-10-01

The remarkable progress in experimental cell transplantation, stem cell biology and genetic engineering promise new therapy and hopefully a cure for patients with end stage heart failure. Engineering of viable cardiac grafts with the potential to grow and remodel will provide new solutions to the serious problems of heart donor shortage. The ability to replace the injured heart muscle will have a dramatic influence on medicine, especially with the increasing number of patients with heart failure. This innovative research, now tested in human patients, still faces significant problems that need to be solved before it can be considered as an established therapeutic tool. The present review will focus on selected topics related to the promise and obstacles associated with cell transplantation, with and without genetic manipulation, for myocardial repair.

Current and emerging global themes in the bioethics of regenerative medicine: the tangled web of stem cell translation

PubMed Central

Chan, Sarah

2017-01-01

Probably the most serious problem facing the field of regenerative medicine today is the challenge of effective translation and development of viable stem cell-based therapies. Particular concerns have been raised over the growing market in unproven cell therapies. In this article, I explore recent developments in the stem cell therapy landscape and argue that while the sale of unproven therapies undoubtedly poses ethical concerns, it must be understood as part of a larger problem at the interface between biomedicine, healthcare, publics, policy and the market. Addressing this will require a broader perspective incorporating the shifting relationships between different stakeholder groups, the global politics of research and innovation, and the evolving role of publics and patients with respect to science. PMID:29119870

Lung Cancer Cell Lines as Tools for Biomedical Discovery and Research

PubMed Central

Girard, Luc; Lockwood, William W.; Lam, Wan L.; Minna, John D.

2010-01-01

Lung cancer cell lines have made a substantial contribution to lung cancer translational research and biomedical discovery. A systematic approach to initiating and characterizing cell lines from small cell and non–small cell lung carcinomas has led to the current collection of more than 200 lung cancer cell lines, a number that exceeds those for other common epithelial cancers combined. The ready availability and widespread dissemination of the lines to investigators worldwide have resulted in more than 9000 citations, including multiple examples of important biomedical discoveries. The high (but not perfect) genomic similarities between lung cancer cell lines and the lung tumor type from which they were derived provide evidence of the relevance of their use. However, major problems including misidentification or cell line contamination remain. Ongoing studies and new approaches are expected to reveal the full potential of the lung cancer cell line panel. PMID:20679594

Cell culture purity issues and DFAT cells

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

Wei, Shengjuan; Department of Animal Sciences, Washington State University, Pullman, WA 99164; Bergen, Werner G.

2013-04-12

Highlights: •DFAT cells are progeny cells derived from dedifferentiated mature adipocytes. •Common problems in this research is potential cell contamination of initial cultures. •The initial cell culture purity is crucial in DFAT cell research field. -- Abstract: Dedifferentiation of mature adipocytes, in vitro, has been pursued/documented for over forty years. The subsequent progeny cells are named dedifferentiated adipocyte-derived progeny cells (DFAT cells). DFAT cells are proliferative and likely to possess mutilineage potential. As a consequence, DFAT cells and their progeny/daughter cells may be useful as a potential tool for various aspects of tissue engineering and as potential vectors for themore » alleviation of several disease states. Publications in this area have been increasing annually, but the purity of the initial culture of mature adipocytes has seldom been documented. Consequently, it is not always clear whether DFAT cells are derived from dedifferentiated mature (lipid filled) adipocytes or from contaminating cells that reside in an impure culture.« less

Silicon-sheet and thin-film cell and module technology potential: Issue study

NASA Technical Reports Server (NTRS)

Shimada, K.; Costogue, E. N.; Ferber, R. R.

1984-01-01

The development of high-efficiency low-cost crystalline silicon ribbon and thih-film solar cells for the energy national photovoltaics program was examined. The findings of an issue study conducted are presented. The collected data identified the status of the technology, future research needs, and problems experienced. The potentials of present research activities to meet the Federal/industry long-term technical goal of achieving 15 cents per kilowatt-hour levelized PV energy cost are assessed. Recommendations for future research needs related to crystalline silicon ribbon and thin-film technologies for flat-plate collectors are also included.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions.

Human Lymphocytes

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. The objective of the research was to define a way to differentiate between effects due to microgravity and those due to possible stress from non-optimal spaceflight conditions.

Feasibility survey on international cooperation for high efficiency energy conversion technology in fiscal 1993

NASA Astrophysics Data System (ADS)

1994-03-01

Following cooperative researches on fuel cell jointly conducted by NEDO and EGAT (Electricity Generating Authority of Thailand), the survey on international cooperation relating to high efficiency energy conversion technology was carried out for the ASEAN countries. The paper summed up the results of the survey. The study of the international cooperation is made for the following three items: a program for periodical exchange of information with EGAT, a project for cooperative research on phosphoric acid fuel cell in Indonesia, and a project for cooperative research with EGAT on electric power storage by advanced battery. In Malaysia, which is small in scale of state, part of the Ministry of Energy, Telecommunication and Posts is only in charge of the energy issue. Therefore, the situation is that they cannot answer well to many items of research/development cooperation brought in from Japan. The item of medium- and long-term developmental research in the Philippines is about the problems which are seen subsequently in the Manila metropolitan area where the problem of outage is being settled. Accordingly, it is essential to promote the cooperative research, well confirming policies and systems of the Ministry of Energy and the national electricity corporation.

CAREST—Multilingual Regional Integration for Health Promotion and Research on Sickle Cell Disease and Thalassemia

PubMed Central

Knight-Madden, Jennifer; Romana, Marc; Villaescusa, Rinaldo; Reid, Marvin; Etienne-Julan, Maryse; Boutin, Laurence; Elana, Gisèle; Elenga, Narcisse; Wheeler, Gillian; Lee, Ketty; Nieves, Rosa; Jones Lecointe, Althea; Lalanne-Mistrih, Marie-Laure; Loko, Gylna; Keclard-Christophe, Lisiane

2016-01-01

Sickle cell disease (SCD) is a significant problem in the Caribbean, where many individuals have African and Asian forebears. However, reliable prevalence data and specific health care programs for SCD are often missing in this region. Closer collaboration between Caribbean territories initiated in 2006 to set up strategies to promote better equity in the health care system for SCD patients led to the formation of CAREST: the Caribbean Network of Researchers on Sickle Cell Disease and Thalassemia. We present the effectiveness of collaborations established by CAREST to promote SCD newborn screening programs and early childhood care, to facilitate health worker training and approaches for prevention and treatment of SCD complications, and to carry out inter-Caribbean research studies. PMID:26999505

[Nuclear transfer and therapeutic cloning].

PubMed

Xu, Xiao-Ming; Lei, An-Min; Hua, Jin-Lian; Dou, Zhong-Ying

2005-03-01

Nuclear transfer and therapeutic cloning have widespread and attractive prospects in animal agriculture and biomedical applications. We reviewed that the quality of oocytes and nuclear reprogramming of somatic donor cells were the main reasons of the common abnormalities in cloned animals and the low efficiency of cloning and showed the problems and outlets in therapeutic cloning, such as some basic problems in nuclear transfer affected clinical applications of therapeutic cloning. Study on isolation and culture of nuclear transfer embryonic stem (ntES) cells and specific differentiation of ntES cells into important functional cells should be emphasized and could enhance the efficiency. Adult stem cells could help to cure some great diseases, but could not replace therapeutic cloning. Ethics also impeded the development of therapeutic cloning. It is necessary to improve many techniques and reinforce the research of some basic theories, then somatic nuclear transfer and therapeutic cloning may apply to agriculture reproduction and benefit to human life better.

Functional imaging of microdomains in cell membranes.

PubMed

Duggan, James; Jamal, Ghadir; Tilley, Mark; Davis, Ben; McKenzie, Graeme; Vere, Kelly; Somekh, Michael G; O'Shea, Paul; Harris, Helen

2008-10-01

The presence of microdomains or rafts within cell membranes is a topic of intense study and debate. The role of these structures in cell physiology, however, is also not yet fully understood with many outstanding problems. This problem is partly based on the small size of raft structures that presents significant problems to their in vivo study, i.e., within live cell membranes. But the structure and dynamics as well as the factors that control the assembly and disassembly of rafts are also of major interest. In this review we outline some of the problems that the study of rafts in cell membranes present as well as describing some views of what are considered the generalised functions of membrane rafts. We point to the possibility that there may be several different 'types' of membrane raft in cell membranes and consider the factors that affect raft assembly and disassembly, particularly, as some researchers suggest that the lifetimes of rafts in cell membranes may be sub-second. We attempt to review some of the methods that offer the ability to interrogate rafts directly as well as describing factors that appear to affect their functionality. The former include both near-field and far-field optical approaches as well as scanning probe techniques. Some of the advantages and disadvantages of these techniques are outlined. Finally, we describe our own views of raft functionality and properties, particularly, concerning the membrane dipole potential, and describe briefly some of the imaging strategies we have developed for their study.

"Cancer Cell Biology:" A Student-Centered Instructional Module Exploring the Use of Multimedia to Enrich Interactive, Constructivist Learning of Science

ERIC Educational Resources Information Center

Bockholt, Susanne M.; West, J. Paige; Bollenbacher, Walter E.

2003-01-01

Multimedia has the potential of providing bioscience education novel learning environments and pedagogy applications to foster student interest, involve students in the research process, advance critical thinking/problem-solving skills, and develop conceptual understanding of biological topics. "Cancer Cell Biology," an interactive, multimedia,…

Research, development and pilot production of high output thin silicon solar cells

NASA Technical Reports Server (NTRS)

Iles, P. A.

1976-01-01

Work was performed to define and apply processes which could lead to high output from thin (2-8 mils) silicon solar cells. The overall problems are outlined, and two satisfactory process sequences were developed. These sequences led to good output cells in the thickness range to just below 4 mils; although the initial contract scope was reduced, one of these sequences proved capable of operating beyond a pilot line level, to yield good quality 4-6 mil cells of high output.

Getting to the root of plant biology: impact of the Arabidopsis genome sequence on root research

PubMed Central

Benfey, Philip N.; Bennett, Malcolm; Schiefelbein, John

2010-01-01

Summary Prior to the availability of the genome sequence, the root of Arabidopsis had attracted a small but ardent group of researchers drawn to its accessibility and developmental simplicity. Roots are easily observed when grown on the surface of nutrient agar media, facilitating analysis of responses to stimuli such as gravity and touch. Developmental biologists were attracted to the simple radial organization of primary root tissues, which form a series of concentric cylinders around the central vascular tissue. Equally attractive was the mode of propagation, with stem cells at the tip giving rise to progeny that were confined to cell files. These properties of root development reduced the normal four-dimensional problem of development (three spatial dimensions and time) to a two-dimensional problem, with cell type on the radial axis and developmental time along the longitudinal axis. The availability of the complete Arabidopsis genome sequence has dramatically accelerated traditional genetic research on root biology, and has also enabled entirely new experimental strategies to be applied. Here we review examples of the ways in which availability of the Arabidopsis genome sequence has enhanced progress in understanding root biology. PMID:20409273

Reprogramming cells from Gulf War veterans into neurons to study Gulf War illness.

PubMed

Qiang, Liang; Rao, Anand N; Mostoslavsky, Gustavo; James, Marianne F; Comfort, Nicole; Sullivan, Kimberly; Baas, Peter W

2017-05-16

Gulf War illness (GWI), which afflicts at least 25% of veterans who served in the 1990-1991 war in the Persian Gulf, is thought to be caused by deployment exposures to various neurotoxicants, including pesticides, anti-nerve gas pills, and low-level nerve agents including sarin/cyclosarin. GWI is a multisymptom disorder characterized by fatigue, joint pain, cognitive problems, and gastrointestinal complaints. The most prominent symptoms of GWI (memory problems, poor attention/concentration, chronic headaches, mood alterations, and impaired sleep) suggest that the disease primarily affects the CNS. Development of urgently needed treatments depends on experimental models appropriate for testing mechanistic hypotheses and for screening therapeutic compounds. Rodent models have been useful thus far, but are limited by their inability to assess the contribution of genetic or epigenetic background to the disease, and because disease-vulnerable proteins and pathways may be different in humans relative to rodents. As of yet, no postmortem tissue from the veterans has become available for research. We are moving forward with a paradigm shift in the study of GWI, which utilizes contemporary stem cell technology to convert somatic cells from Gulf War veterans into pluripotent cell lines that can be differentiated into various cell types, including neurons, glia, muscle, or other relevant cell types. Such cell lines are immortal and will be a resource for GWI researchers to pursue mechanistic hypotheses and therapeutics. © 2017 American Academy of Neurology.

Reprogramming cells from Gulf War veterans into neurons to study Gulf War illness

PubMed Central

Qiang, Liang; Rao, Anand N.; Mostoslavsky, Gustavo; James, Marianne F.; Comfort, Nicole; Sullivan, Kimberly

2017-01-01

Gulf War illness (GWI), which afflicts at least 25% of veterans who served in the 1990–1991 war in the Persian Gulf, is thought to be caused by deployment exposures to various neurotoxicants, including pesticides, anti–nerve gas pills, and low-level nerve agents including sarin/cyclosarin. GWI is a multisymptom disorder characterized by fatigue, joint pain, cognitive problems, and gastrointestinal complaints. The most prominent symptoms of GWI (memory problems, poor attention/concentration, chronic headaches, mood alterations, and impaired sleep) suggest that the disease primarily affects the CNS. Development of urgently needed treatments depends on experimental models appropriate for testing mechanistic hypotheses and for screening therapeutic compounds. Rodent models have been useful thus far, but are limited by their inability to assess the contribution of genetic or epigenetic background to the disease, and because disease-vulnerable proteins and pathways may be different in humans relative to rodents. As of yet, no postmortem tissue from the veterans has become available for research. We are moving forward with a paradigm shift in the study of GWI, which utilizes contemporary stem cell technology to convert somatic cells from Gulf War veterans into pluripotent cell lines that can be differentiated into various cell types, including neurons, glia, muscle, or other relevant cell types. Such cell lines are immortal and will be a resource for GWI researchers to pursue mechanistic hypotheses and therapeutics. PMID:28507260

The effects of clamp torque, humidity, and carbon oxygen poisoning on PEM fuel cell performance

NASA Astrophysics Data System (ADS)

Lee, Woo-Kum

2000-10-01

Proton exchange membrane fuel cell (PEMFC) is attracting much attention as a power source of electric vehicles due to high power density capability. Although there has been much research and development done on PEWC, there are still many problems to be solved. One of the major problems is water management inside the fuel cell. The performance of the fuel cell is strongly influenced by the state of hydration of the membrane. If the membrane is too dry, its conductivity drops resulting in reduced cell performance. An excess of water in the fuel cell can lead to flooding problems, also resulting in performance drop. This dissertation presents experimental data that may be used to verify numerical simulations of a PEM fuel cell. The key to this usefulness is the closure of a water balance in the fuel cell for various operating conditions. The closure results from experimental data showed that the inlet gas streams are not fully saturated with water vapor. Another key to the usefulness of the data is the measurement of the internal compression pressure that is exerted on the gas diffusion layer. Data is presented to show the effect of this compression on the performance of the PEMFC and on the water balance results. Another problem in application of a PEM fuel cell is CO poisoning on the MEA. Gas reformed from methanol or gasoline contains small amount of CO resulting in significant decreasing fuel cell performance. Several recovery techniques were discussed to solve the CO problem. The use of Pt-Ru alloys as anode catalyst has shown that CO is oxidized at more negative potentials as compared to pure Pt. According to the result, an improvement has been achieved at CO level 5 ppm. Another method to prevent CO poisoning has been described by blowing 5% of air into the anode side. The result shows that the performance recovers very quickly as the air is injected during reformate (50 ppm CO).

The NASA Lithium Technology Program

NASA Technical Reports Server (NTRS)

Halpert, G.; Frank, H.

1984-01-01

NASA is sponsoring research to develop advanced primary and secondary lithium cells. Lithium cells are conducive to aerospace use because they have high specific energy, volumetric energy density, and long storage capability. The primary cell research is centered on the Li/SOCl2 system. It is in the late development stage and all effort is being placed on resolving safety problems. The secondary cell, which is in the development stage, is the Li/TiS2 system. The objective is to produce a 100 wh/kg cell capable of operating in a geosynchronous orbit for 10 years. The development of improved conductivity polymeric films for electrochemical use is also being investigated. The lightweight batteries will have many applications in space and are already being prepared for the 1986 Galileo mission to Jupiter.

Progress in Aluminum Electrolysis Control and Future Direction for Smart Aluminum Electrolysis Plant

NASA Astrophysics Data System (ADS)

Zhang, Hongliang; Li, Tianshuang; Li, Jie; Yang, Shuai; Zou, Zhong

2017-02-01

The industrial aluminum reduction cell is an electrochemistry reactor that operates under high temperatures and highly corrosive conditions. However, these conditions have restricted the measurement of key control parameters, making the control of aluminum reduction cells a difficult problem in the industry. Because aluminum electrolysis control systems have a significant economic influence, substantial research has been conducted on control algorithms, control systems and information systems for aluminum reduction cells. This article first summarizes the development of control systems and then focuses on the progress made since 2000, including alumina concentration control, temperature control and electrolyte molecular ratio control, fault diagnosis, cell condition prediction and control system expansion. Based on these studies, the concept of a smart aluminum electrolysis plant is proposed. The frame construction, key problems and current progress are introduced. Finally, several future directions are discussed.

Culture conditions tailored to the cell of origin are critical for maintaining native properties and tumorigenicity of glioma cells

PubMed Central

Ledur, Pítia F.; He, Hua; Harris, Alexandra R.; Minussi, Darlan C.; Zhou, Hai-Yan; Shaffrey, Mark E.; Asthagiri, Ashok; Lopes, Maria Beatriz S.; Schiff, David; Lu, Yi-Cheng; Mandell, James W.; Lenz, Guido; Zong, Hui

2016-01-01

Background Cell culture plays a pivotal role in cancer research. However, culture-induced changes in biological properties of tumor cells profoundly affect research reproducibility and translational potential. Establishing culture conditions tailored to the cancer cell of origin could resolve this problem. For glioma research, it has been previously shown that replacing serum with defined growth factors for neural stem cells (NSCs) greatly improved the retention of gene expression profile and tumorigenicity. However, among all molecular subtypes of glioma, our laboratory and others have previously shown that the oligodendrocyte precursor cell (OPC) rather than the NSC serves as the cell of origin for the proneural subtype, raising questions regarding the suitability of NSC-tailored media for culturing proneural glioma cells. Methods OPC-originated mouse glioma cells were cultured in conditions for normal OPCs or NSCs, respectively, for multiple passages. Gene expression profiles, morphologies, tumorigenicity, and drug responsiveness of cultured cells were examined in comparison with freshly isolated tumor cells. Results OPC media-cultured glioma cells maintained tumorigenicity, gene expression profiles, and morphologies similar to freshly isolated tumor cells. In contrast, NSC-media cultured glioma cells gradually lost their OPC features and most tumor-initiating ability and acquired heightened sensitivity to temozolomide. Conclusions To improve experimental reproducibility and translational potential of glioma research, it is important to identify the cell of origin, and subsequently apply this knowledge to establish culture conditions that allow the retention of native properties of tumor cells. PMID:27106408

Ethical Problems in Fetal Research

ERIC Educational Resources Information Center

Nathan, David G.

1975-01-01

The characteristics and frequency of Cooley's anemia and sickle cell anemia were briefly reviewed. As well the genetic rationale for antenatal diagnosis of these conditions were discussed along with the present status of diagnostic technology. (Author/RK)

Defining the phenotype of young healthy nucleus pulposus cells: recommendations of the Spine Research Interest Group at the 2014 annual ORS meeting.

PubMed

Risbud, Makarand V; Schoepflin, Zachary R; Mwale, Fackson; Kandel, Rita A; Grad, Sibylle; Iatridis, James C; Sakai, Daisuke; Hoyland, Judith A

2015-03-01

Low back pain is a major physical and socioeconomic problem. Degeneration of the intervertebral disc and especially that of nucleus pulposus (NP) has been linked to low back pain. In spite of much research focusing on the NP, consensus among the research community is lacking in defining the NP cell phenotype. A consensus agreement will allow easier distinguishing of NP cells from annulus fibrosus (AF) cells and endplate chondrocytes, a better gauge of therapeutic success, and a better guidance of tissue-engineering-based regenerative strategies that attempt to replace lost NP tissue. Most importantly, a clear definition will further the understanding of physiology and function of NP cells, ultimately driving development of novel cell-based therapeutic modalities. The Spine Research Interest Group at the 2014 Annual ORS Meeting in New Orleans convened with the task of compiling a working definition of the NP cell phenotype with hope that a consensus statement will propel disc research forward into the future. Based on evaluation of recent studies describing characteristic NP markers and their physiologic relevance, we make the recommendation of the following healthy NP phenotypic markers: stabilized expression of HIF-1α, GLUT-1, aggrecan/collagen II ratio >20, Shh, Brachyury, KRT18/19, CA12, and CD24. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

[Hepatosplenic T-cell lymphoma: The problems of diagnosis and treatment].

PubMed

Chernova, N G; Julhakyan, H L; Vinogradova, Yu E; Sidorova, Yu V; Ryzhikova, N V; Korzhova, S M; Sinitsyna, M N; Tikhomirov, D S; Naumova, E V; Obukhova, T N; Dvirnyk, V N; Sudarikov, A B; Kovrigina, A M; Kravchenko, S K; Melikyan, A L; Kuzmina, L A; Galtseva, I V; Smirnova, S Yu; Gemdzhian, E G; Zvonkov, E E; Parovichnikova, E N; Savchenko, V G

2016-01-01

In the past decade, a notable advance has been made in the understanding of the pathogenesis of NK/T-cell lymphomas; however, their diagnosis remains difficult because of their rarity and clinical and morphological variabilities. The paper generalizes the ten-year experience of the Hematology Research Center, Ministry of Health of Russia, in diagnosing and treating hepatosplenic T-cell lymphoma (HSTL), considers the problems of differential diagnosis with other hematological diseases occurring with similar clinical and laboratory symptoms, and lays down current approaches to the diagnosis and treatment of this condition. A clinician's view of the problem of diagnosis and treatment of this disease is given. HSTL is shown to be a heterogeneous group of diseases differing in a T-cell receptor chain gene rearrangement, the clinical course of the disease, and overall survival (OS). According to our data, 3-year OS was 12%; the median survival was 26 months. Two-year OS for γδ and αβ HSTL was equal to 25 and 70%, respectively. The difference in OS for the variants of HSTL failed to reach statistical significance (because the sample might be insufficient).

Attributed relational graphs for cell nucleus segmentation in fluorescence microscopy images.

PubMed

Arslan, Salim; Ersahin, Tulin; Cetin-Atalay, Rengul; Gunduz-Demir, Cigdem

2013-06-01

More rapid and accurate high-throughput screening in molecular cellular biology research has become possible with the development of automated microscopy imaging, for which cell nucleus segmentation commonly constitutes the core step. Although several promising methods exist for segmenting the nuclei of monolayer isolated and less-confluent cells, it still remains an open problem to segment the nuclei of more-confluent cells, which tend to grow in overlayers. To address this problem, we propose a new model-based nucleus segmentation algorithm. This algorithm models how a human locates a nucleus by identifying the nucleus boundaries and piecing them together. In this algorithm, we define four types of primitives to represent nucleus boundaries at different orientations and construct an attributed relational graph on the primitives to represent their spatial relations. Then, we reduce the nucleus identification problem to finding predefined structural patterns in the constructed graph and also use the primitives in region growing to delineate the nucleus borders. Working with fluorescence microscopy images, our experiments demonstrate that the proposed algorithm identifies nuclei better than previous nucleus segmentation algorithms.

A summary report on the Flat-Plate Solar Array Project Workshop on Transparent Conducting Polymers

NASA Technical Reports Server (NTRS)

Kachare, R.; Moacanin, J.

1985-01-01

The proceedings and technical discussions of a workshop on Transparent Conducting Polymers (TCP) for solar cell applications are reported. This is in support of the Device Research Task of the Flat-Flate Solar Array Project. The workshop took place on January 11 and 12, 1985, in Santa Barbara, California. Participants included university and industry researchers. The discussions focused on the electronic and optical properties of TCP, and on experimental issues and problems that should be addressed for high-efficiency solar cell application.

Cell lines authentication and mycoplasma detection as minimun quality control of cell lines in biobanking.

PubMed

Corral-Vázquez, C; Aguilar-Quesada, R; Catalina, P; Lucena-Aguilar, G; Ligero, G; Miranda, B; Carrillo-Ávila, J A

2017-06-01

Establishment of continuous cell lines from human normal and tumor tissues is an extended and useful methodology for molecular characterization of cancer pathophysiology and drug development in research laboratories. The exchange of these cell lines between different labs is a common practice that can compromise assays reliability due to contamination with microorganism such as mycoplasma or cells from different flasks that compromise experiment reproducibility and reliability. Great proportions of cell lines are contaminated with mycoplasma and/or are replaced by cells derived for a different origin during processing or distribution process. The scientific community has underestimated this problem and thousand of research experiment has been done with cell lines that are incorrectly identified and wrong scientific conclusions have been published. Regular contamination and authentication tests are necessary in order to avoid negative consequences of widespread misidentified and contaminated cell lines. Cell banks generate, store and distribute cell lines for research, being mandatory a consistent and continuous quality program. Methods implementation for guaranteeing both, the absence of mycoplasma and authentication in the supplied cell lines, has been performed in the Andalusian Health System Biobank. Specifically, precise results were obtained using real time PCR detection for mycoplasma and 10 STRs identification by capillary electrophoresis for cell line authentication. Advantages and disadvantages of these protocols are discussed.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc., has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc., is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Microgravity

NASA Image and Video Library

2004-04-15

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc. has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc. is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Single cell biology beyond the era of antibodies: relevance, challenges, and promises in biomedical research.

PubMed

Abraham, Parvin; Maliekal, Tessy Thomas

2017-04-01

Research of the past two decades has proved the relevance of single cell biology in basic research and translational medicine. Successful detection and isolation of specific subsets is the key to understand their functional heterogeneity. Antibodies are conventionally used for this purpose, but their relevance in certain contexts is limited. In this review, we discuss some of these contexts, posing bottle neck for different fields of biology including biomedical research. With the advancement of chemistry, several methods have been introduced to overcome these problems. Even though microfluidics and microraft array are newer techniques exploited for single cell biology, fluorescence-activated cell sorting (FACS) remains the gold standard technique for isolation of cells for many biomedical applications, like stem cell therapy. Here, we present a comprehensive and comparative account of some of the probes that are useful in FACS. Further, we illustrate how these techniques could be applied in biomedical research. It is postulated that intracellular molecular markers like nucleostemin (GNL3), alkaline phosphatase (ALPL) and HIRA can be used for improving the outcome of cardiac as well as bone regeneration. Another field that could utilize intracellular markers is diagnostics, and we propose the use of specific peptide nucleic acid probes (PNPs) against certain miRNAs for cancer surgical margin prediction. The newer techniques for single cell biology, based on intracellular molecules, will immensely enhance the repertoire of possible markers for the isolation of cell types useful in biomedical research.

[Transplantation in diabetes type 1--current problems and perspectives].

PubMed

Wasikowa, Renata; Noczyńska, Anna; Basiak, Aleksander

2004-01-01

Diabetes type 1 is, as we know, a chronic progressive disease, which requires a substitutional therapy with insulin for the whole life. The cause is a definite destruction of the pancreatic beta cells. For many years there have been intensive investigations on the possibility to obtain a complete, persistent withdrawal of the symptoms. Substitution of the destroyed, not active cells, could take place after transplantation of the whole pancreas, transplantation of pancreatic islets or transplantation of stem cells. This is now the only method which may cause an independence from exogenous insulin, persistent normoglycemia, normal HbA1c level, without risk of hypoglycemia. Pancreas and islets transplantations, however, are connected till now with the necessity of an immunosuppressive therapy for the whole life, with the toxicity of the drugs, incidence of frequent infections and malignancy. Pancreas transplantation is a serious surgical intervention, connected with numerous risks and complications, considerably less risk appears in islet cell transplantations. Since 2000 exclusively islet cell transplantations have been performed. One of the leading centers is Edmonton, where professor Shapiro prepared the so called. Edmonton protocol which is characterized by using corticosteroid-free immunosuppressive drugs, islet cells from two or more donors, repeated till the attainment of insulin dependence. A problem now is that the islets are obtained from cadavers. Therefore intensive research is conducted for alternative sources of beta cells. At this moment it is mostly preferred for receiving a sufficient number of insulin producing cells to develop stem cells with a subsequent differentiation to insulin producing cells. The mentioned cells have an unlimited ability of reproduction, in this case also immunosuppressive therapy is not necessary. Alternative sources of beta cells are cells achieved on the genetic engineering, embryonic or adult somatic stem cells. It is however important to stress, that adult stem cells as insulin producing cells are not unequivocally identified. For obtaining better, permanent results after transplantation the following are important: optimalization of "islands growth" in the liver, prevention of the early inflammations, further development of highly selective, well tolerated, corticosteroid-free immunosuppressive drugs, identification of rejecting markers, induction of immunotolerance, micro- and macro-capsulation of the islets to protect the recipient against the immunological attack. Several multicenter studies in important scientific centers are opened, there is also Juvenile Research Foundation International. In spite of a permanent progress there are still many important problems to solve. It is necessary to institute further multicenter, international research to ascertain the effect of transplantation concerning the normalisation of glycemia, prevention or inhibition of the progress of diabetic complications and to prolong the life span in patients with type 1 diabetes after transplantation.

Stem cell research and therapies in Argentina: the legal and regulatory approach.

PubMed

de Arzuaga, Fabiana C

2013-12-01

Argentina has a significant number of researchers in public and private institutions conducting research in regenerative medicine and stem cells. There is not specific legislation in this area; however, the National Ministry of Health has issued regulations under the scope of the Transplant Act and the Medicines Act. Alongside the groups doing research, it is possible to find professionals offering experimental stem cell therapies to patients. These professionals take refuge in the term "medical practice" and sell experimental treatment to patients with no guarantee of safety and security given that they were not tested in clinical research. These practices offered to patients in a scheme, apparently legal, are generating an important number of judicial actions requesting the payment of said treatments. The decisions of the courts ordering payment in most cases are generating a transfer of funds from patients, social welfare systems, and the state to medical centers offering stem cell experimental therapies. This article describes the current regulations as well as the course of action to solve the emerging problems of these new technologies at legislative level.

Numerical modelling of closed-cell aluminium foam under dynamic loading

NASA Astrophysics Data System (ADS)

Hazell, Paul; Kader, M. A.; Islam, M. A.; Escobedo, J. P.; Saadatfar, M.

2015-06-01

Closed-cell aluminium foams are extensively used in aerospace and automobile industries. The understanding of their behaviour under impact loading conditions is extremely important since impact problems are directly related to design of these engineering structures. This research investigates the response of a closed-cell aluminium foam (CYMAT) subjected to dynamic loading using the finite element software ABAQUS/explicit. The aim of this research is to numerically investigate the material and structural properties of closed-cell aluminium foam under impact loading conditions with interest in shock propagation and its effects on cell wall deformation. A μ-CT based 3D foam geometry is developed to simulate the local cell collapse behaviours. A number of numerical techniques are applied for modelling the crush behaviour of aluminium foam to obtain the more accurate results. The simulation results are compared with experimental data. Comparison of the results shows a good correlation between the experimental results and numerical predictions.

Therapeutic cloning research and ethical oversight.

PubMed

Spriggs, M

2003-08-01

Cloning Trevor, a story about therapeutic cloning research, appeared in the June issue of The Atlantic Monthly. The story gives a human face to the people whom therapeutic cloning could benefit. It presents an argument for government funding and it puts the usual calls for a moratorium on embryonic stem cell research to allow for more debate, in a less favourable light. The story also highlights some problems with ethical oversight.

The East German Research Landscape in Transition. Part B. Non-University Institutes

DTIC Science & Technology

1993-03-02

struc- tures and metal ions: Basic research of the biosorption , bioaccumulation and metal desorption mechanisms Influence and increase of the sorption...microbial corrosion problems - Investigation of che interaction between microbial structures and metal ions: Basic research of the biosorption ...Additional work has been undertaken on the response of the cell at the molecular level to various stresses, including heat and heavy metals . In both cases

PICsar: Particle in cell pulsar magnetosphere simulator

NASA Astrophysics Data System (ADS)

Belyaev, Mikhail A.

2016-07-01

PICsar simulates the magnetosphere of an aligned axisymmetric pulsar and can be used to simulate other arbitrary electromagnetics problems in axisymmetry. Written in Fortran, this special relativistic, electromagnetic, charge conservative particle in cell code features stretchable body-fitted coordinates that follow the surface of a sphere, simplifying the application of boundary conditions in the case of the aligned pulsar; a radiation absorbing outer boundary, which allows a steady state to be set up dynamically and maintained indefinitely from transient initial conditions; and algorithms for injection of charged particles into the simulation domain. PICsar is parallelized using MPI and has been used on research problems with 1000 CPUs.

Fuzzy entropy thresholding and multi-scale morphological approach for microscopic image enhancement

NASA Astrophysics Data System (ADS)

Zhou, Jiancan; Li, Yuexiang; Shen, Linlin

2017-07-01

Microscopic images provide lots of useful information for modern diagnosis and biological research. However, due to the unstable lighting condition during image capturing, two main problems, i.e., high-level noises and low image contrast, occurred in the generated cell images. In this paper, a simple but efficient enhancement framework is proposed to address the problems. The framework removes image noises using a hybrid method based on wavelet transform and fuzzy-entropy, and enhances the image contrast with an adaptive morphological approach. Experiments on real cell dataset were made to assess the performance of proposed framework. The experimental results demonstrate that our proposed enhancement framework increases the cell tracking accuracy to an average of 74.49%, which outperforms the benchmark algorithm, i.e., 46.18%.

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

Identification of Yeast V-ATPase Mutants by Western Blots Analysis of Whole Cell Lysates

NASA Astrophysics Data System (ADS)

Parra-Belky, Karlett

2002-11-01

A biochemistry laboratory was designed for an undergraduate course to help students better understand the link between molecular engineering and biochemistry. Students identified unknown yeast strains with high specificity using SDS-PAGE and Western blot analysis of whole cell lysates. This problem-solving exercise is a common application of biochemistry in biotechnology research. Three different strains were used: a wild-type and two mutants for the proton pump vacuolar ATPase (V-ATPase). V-ATPases are multisubunit enzymes and the mutants used were deletion mutants; each lacked one structural gene of the complex. After three, three-hour labs, mutant strains were easily identified by the students and distinguished from wild-type cells analyzing the pattern of SDS-PAGE distribution of proteins. Identifying different subunits of one multimeric protein allowed for discussion of the structure and function of this metabolic enzyme, which captured the interest of the students. The experiment can be adapted to other multimeric protein complexes and shows improvement of the described methodology over previous reports, perhaps because the problem and its solution are representative of the type of techniques currently used in research labs.

Status of FEP encapsulated solar cell modules used in terrestrial applications

NASA Technical Reports Server (NTRS)

Ratajczak, A. F.; Forestieri, A. F.

1974-01-01

The Lewis Research Center has been engaged in transferring the FEP encapsulated solar cell technology developed for the space program to terrestrial applications. FEP encapsulated solar cell modules and arrays were designed and built expressly for terrestrial applications. Solar cell power systems were installed at three different land sites, while individual modules are undergoing marine environment tests. Four additional power systems are being completed for installation during the summer of 1974. These tests have revealed some minor problems which have been corrected. The results confirm the inherent utility of FEP encapsulated terrestrial solar cell systems.

All-Weather Solar Cells: A Rising Photovoltaic Revolution.

PubMed

Tang, Qunwei

2017-06-16

Solar cells have been considered as one of the foremost solutions to energy and environmental problems because of clean, high efficiency, cost-effective, and inexhaustible features. The historical development and state-of-the-art solar cells mainly focus on elevating photoelectric conversion efficiency upon direct sunlight illumination. It is still a challenging problem to realize persistent high-efficiency power generation in rainy, foggy, haze, and dark-light conditions (night). The physical proof-of-concept for all-weather solar cells opens a door for an upcoming photovoltaic revolution. Our group has been exploring constructive routes to build all-weather solar cells so that these advanced photovoltaic technologies can be an indication for global solar industry in bringing down the cost of energy harvesting. How the all-weather solar cells are built without reducing photo performances and why such architectures can realize electricity outputs with no visible-light are discussed. Potential pathways and opportunities to enrich all-weather solar cell families are envisaged. The aspects discussed here may enable researchers to develop undiscovered abilities and to explore wide applications of advanced photovoltaics. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cell Culturing of Cytoskeleton

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc., has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc., is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Cell Culturing of Cytoskeleton

NASA Technical Reports Server (NTRS)

2004-01-01

Biomedical research offers hope for a variety of medical problems, from diabetes to the replacement of damaged bone and tissues. Bioreactors, which are used to grow cells and tissue cultures, play a major role in such research and production efforts. Cell culturing, such as this bone cell culture, is an important part of biomedical research. The BioDyn payload includes a tissue engineering investigation. The commercial affiliate, Millenium Biologix, Inc. has been conducting bone implant experiments to better understand how synthetic bone can be used to treat bone-related illnesses and bone damaged in accidents. On STS-95, the BioDyn payload will include a bone cell culture aimed to help develop this commercial synthetic bone product. Millenium Biologix, Inc. is exploring the potential for making human bone implantable materials by seeding its proprietary artificial scaffold material with human bone cells. The product of this tissue engineering experiment using the Bioprocessing Modules (BPMs) on STS-95 is space-grown bone implants, which could have potential for dental implants, long bone grafts, and coating for orthopedic implants such as hip replacements.

Research methodology of the artifact effect in the blood to the result of cell classification

NASA Astrophysics Data System (ADS)

Polyakov, E. V.; Nikitaev, V. G.; Seldyukov, S. O.

2017-01-01

A study of the influence of artifacts on the result of the division of blasts and lymphocytes in the problem of diagnosing the types of acute leukemia was conducted. A group of artifacts was formed to conduct the study. Preliminary studies allowed to estimate the degree of influence of artifacts on the results of the classification of red blood cells.

Proceedings of the Flat-plate Solar Array Project Research Forum on the High-speed Growth and Characterization of Crystals for Solar Cells

NASA Technical Reports Server (NTRS)

Dumas, K. A. (Editor)

1984-01-01

Theoretical and experimental phenomena, applications, and characterization including stress/strain and other problem areas that limit the rate of growth of crystals suitable for processing into efficient, cost-effective solar cells are discussed. Melt spinning, ribbon growth, rapid solidification, laser recrystallization, and ignot growth of silicon and metals are also discussed.

Nicholas J. Grundl | NREL

Science.gov Websites

-3228 Research Interests Application of numerical methods to process problems Fuel and chemical biochemistry and numerical methods), University of Wisconsin at Madison, 2009-2014 Professional Experience Stem Cells Under Defined Conditions," Tissue Engineering Part C Methods (2013)

Continuous beer fermentation using immobilized yeast cell bioreactor systems.

PubMed

Brányik, Tomás; Vicente, António A; Dostálek, Pavel; Teixeira, José A

2005-01-01

Traditional beer fermentation and maturation processes use open fermentation and lager tanks. Although these vessels had previously been considered indispensable, during the past decades they were in many breweries replaced by large production units (cylindroconical tanks). These have proved to be successful, both providing operating advantages and ensuring the quality of the final beer. Another promising contemporary technology, namely, continuous beer fermentation using immobilized brewing yeast, by contrast, has found only a limited number of industrial applications. Continuous fermentation systems based on immobilized cell technology, albeit initially successful, were condemned to failure for several reasons. These include engineering problems (excess biomass and problems with CO(2) removal, optimization of operating conditions, clogging and channeling of the reactor), unbalanced beer flavor (altered cell physiology, cell aging), and unrealized cost advantages (carrier price, complex and unstable operation). However, recent development in reactor design and understanding of immobilized cell physiology, together with application of novel carrier materials, could provide a new stimulus to both research and application of this promising technology.

Differential equations with applications in cancer diseases.

PubMed

Ilea, M; Turnea, M; Rotariu, M

2013-01-01

Mathematical modeling is a process by which a real world problem is described by a mathematical formulation. The cancer modeling is a highly challenging problem at the frontier of applied mathematics. A variety of modeling strategies have been developed, each focusing on one or more aspects of cancer. The vast majority of mathematical models in cancer diseases biology are formulated in terms of differential equations. We propose an original mathematical model with small parameter for the interactions between these two cancer cell sub-populations and the mathematical model of a vascular tumor. We work on the assumption that, the quiescent cells' nutrient consumption is long. One the equations system includes small parameter epsilon. The smallness of epsilon is relative to the size of the solution domain. MATLAB simulations obtained for transition rate from the quiescent cells' nutrient consumption is long, we show a similar asymptotic behavior for two solutions of the perturbed problem. In this system, the small parameter is an asymptotic variable, different from the independent variable. The graphical output for a mathematical model of a vascular tumor shows the differences in the evolution of the tumor populations of proliferating, quiescent and necrotic cells. The nutrient concentration decreases sharply through the viable rim and tends to a constant level in the core due to the nearly complete necrosis in this region. Many mathematical models can be quantitatively characterized by ordinary differential equations or partial differential equations. The use of MATLAB in this article illustrates the important role of informatics in research in mathematical modeling. The study of avascular tumor growth cells is an exciting and important topic in cancer research and will profit considerably from theoretical input. Interpret these results to be a permanent collaboration between math's and medical oncologists.

Children's Media Use and Sleep Problems: Issues and Unanswered Questions. Research Brief

ERIC Educational Resources Information Center

Zimmerman, Frederick J.

2008-01-01

Research shows that most children and adolescents do not get enough high-quality sleep, and that their sleep times appear to have declined over the last two decades. Coinciding with this trend has been the rise in popularity of new media forms including the Internet, video games, cell phones and DVDs. Because of the immediacy and interactivity of…

[The progressive legal vulnerability of embryonic human life in Spain: the law 35/1988 to 14/2006 and law 14/2007].

PubMed

Germán Zurriaráin, Roberto

2009-01-01

This article examines the Laws on Human Assisted Reproduction and Biomedical Research in Spain. The Laws permit the use of human ovules, embryos and fetuses. Close to the technical and ethical problems that carry the research on embryonic stem cells, the detection of induced reprogramming of adult cells to an embryonic stage (iPS) opens up new perspectives in regenerative medicine. It makes unnecessary the use of frozen embryos or produced by nuclear transfer. These reasons would involve a review of the Spanish Legislation in this matter, in order that the human life is an ethical barrier and a fundamental to actual biomedical research.

Landscaping the epigenetic landscape of cancer.

PubMed

Aranda-Anzaldo, Armando; Dent, Myrna A R

2018-06-08

Waddington's epigenetic landscape was introduced in biology for understanding the complex process of metazoan development in an accessible fashion. The epigenetic landscape concept implies the coupling of cell differentiation and tissue/organ morphogenesis under a simple visual metaphor or analogy with significant heuristic value. Yet in recent times the epigenetic landscape has been reduced to an illustration device just for cell differentiation thus diminishing its explanatory power and heuristic value. On the other hand, the current mainstream in cancer research is concentrated on the search for proximate causes but not on achieving a deeper understanding of the phenomenon. Nevertheless an emerging alternative perspective that understands cancer as a problem related to tissue/organ morphology and structural organization is getting wider attention. Within such a perspective here we present and discuss a historically restored, non-reductionist, version of the epigenetic landscape that when applied to the problem of cancer improves our understanding of it as a common biological phenomenon resulting from the uncoupling of morphogenesis and cell differentiation as a consequence of the progressive erosion of the epigenetic landscape. The following discussion aims at finding a general framework, not dependent on proximate causes, for understanding the phenomenon of cancer and suggests new research strategies on this problem but away from the current emphasis on the putative genetic causes of cancer. Copyright © 2018 Elsevier Ltd. All rights reserved.

Modeling Alzheimer’s disease with human induced pluripotent stem (iPS) cells

PubMed Central

Mungenast, Alison E.; Siegert, Sandra; Tsai, Li-Huei

2018-01-01

In the last decade, induced pluripotent stem (iPS) cells have revolutionized the utility of human in vitro models of neurological disease. The iPS-derived and differentiated cells allow researchers to study the impact of a distinct cell type in health and disease as well as performing therapeutic drug screens on a human genetic background. In particular, clinical trials for Alzheimer’s disease (AD) have been often failing. Two of the potential reasons are first, the species gap involved in proceeding from initial discoveries in rodent models to human studies, and second, an unsatisfying patient stratification, meaning subgrouping patients based on the disease severity due to the lack of phenotypic and genetic markers. iPS cells overcome this obstacles and will improve our understanding of disease subtypes in AD. They allow researchers conducting in depth characterization of neural cells from both familial and sporadic AD patients as well as preclinical screens on human cells. In this review, we briefly outline the status quo of iPS cell research in neurological diseases along with the general advantages and pitfalls of these models. We summarize how genome-editing techniques such as CRISPR/Cas will allow researchers to reduce the problem of genomic variability inherent to human studies, followed by recent iPS cell studies relevant to AD. We then focus on current techniques for the differentiation of iPS cells into neural cell types that are relevant to AD research. Finally, we discuss how the generation of three-dimensional cell culture systems will be important for understanding AD phenotypes in a complex cellular milieu, and how both two- and three-dimensional iPS cell models can provide platforms for drug discovery and translational studies into the treatment of AD. PMID:26657644

Modeling Alzheimer's disease with human induced pluripotent stem (iPS) cells.

PubMed

Mungenast, Alison E; Siegert, Sandra; Tsai, Li-Huei

2016-06-01

In the last decade, induced pluripotent stem (iPS) cells have revolutionized the utility of human in vitro models of neurological disease. The iPS-derived and differentiated cells allow researchers to study the impact of a distinct cell type in health and disease as well as performing therapeutic drug screens on a human genetic background. In particular, clinical trials for Alzheimer's disease (AD) have been failing. Two of the potential reasons are first, the species gap involved in proceeding from initial discoveries in rodent models to human studies, and second, an unsatisfying patient stratification, meaning subgrouping patients based on the disease severity due to the lack of phenotypic and genetic markers. iPS cells overcome this obstacles and will improve our understanding of disease subtypes in AD. They allow researchers conducting in depth characterization of neural cells from both familial and sporadic AD patients as well as preclinical screens on human cells. In this review, we briefly outline the status quo of iPS cell research in neurological diseases along with the general advantages and pitfalls of these models. We summarize how genome-editing techniques such as CRISPR/Cas9 will allow researchers to reduce the problem of genomic variability inherent to human studies, followed by recent iPS cell studies relevant to AD. We then focus on current techniques for the differentiation of iPS cells into neural cell types that are relevant to AD research. Finally, we discuss how the generation of three-dimensional cell culture systems will be important for understanding AD phenotypes in a complex cellular milieu, and how both two- and three-dimensional iPS cell models can provide platforms for drug discovery and translational studies into the treatment of AD. Copyright © 2015 Elsevier Inc. All rights reserved.

Successful propagation of shrimp yellow head virus in immortal mosquito cells.

PubMed

Gangnonngiw, Warachin; Kanthong, Nipaporn; Flegel, Timothy W

2010-05-18

Research on crustacean viruses is hampered by the lack of continuous cell lines susceptible to them. To overcome this problem, we previously challenged immortal mosquito and lepidopteran cell lines with shrimp yellow head virus (YHV), followed by serial, split-passage of whole cells, and showed that this produced cells that persistently expressed YHV antigens. To determine whether such insect cultures positive for YHV antigens could be used to infect shrimp Penaeus monodon with YHV, culture supernatants and whole-cell homogenates were used to challenge shrimp by injection. Shrimp injected with culture supernatants could not be infected. However, shrimp injection-challenged with whole-cell homogenates from Passage 5 (early-passage) of such cultures died with histological and clinical signs typical for yellow head disease (YHD), while homogenates of mock-passaged, YHV-challenged cells did not. By contrast, shrimp challenged with cell homogenates of late-passage cultures became infected with YHV, but survived, suggesting that YHV attenuation had occurred during its long-term serial passage in insect cells. Thus, YHV could be propagated successfully in C6/36 mosquito cells and used at low passage numbers as a source of inoculum to initiate lethal infections in shrimp. This partially solves the problem of lack of continuous shrimp cell lines for cultivation of YHV.

Metabolomics Approach for Toxicity Screening of Volatile Substances

EPA Science Inventory

In 2007 the National Research Council envisioned the need for inexpensive, high throughput, cell based toxicity testing methods relevant to human health. High Throughput Screening (HTS) in vitro screening approaches have addressed these problems by using robotics. However, the ch...

Chitosan and alginate types of bio-membrane in fuel cell application: An overview

NASA Astrophysics Data System (ADS)

Shaari, N.; Kamarudin, S. K.

2015-09-01

The major problems of polymer electrolyte membrane fuel cell technology that need to be highlighted are fuel crossovers (e.g., methanol or hydrogen leaking across fuel cell membranes), CO poisoning, low durability, and high cost. Chitosan and alginate-based biopolymer membranes have recently been used to solve these problems with promising results. Current research in biopolymer membrane materials and systems has focused on the following: 1) the development of novel and efficient biopolymer materials; and 2) increasing the processing capacity of membrane operations. Consequently, chitosan and alginate-based biopolymers seek to enhance fuel cell performance by improving proton conductivity, membrane durability, and reducing fuel crossover and electro-osmotic drag. There are four groups of chitosan-based membranes (categorized according to their reaction and preparation): self-cross-linked and salt-complexed chitosans, chitosan-based polymer blends, chitosan/inorganic filler composites, and chitosan/polymer composites. There are only three alginate-based membranes that have been synthesized for fuel cell application. This work aims to review the state-of-the-art in the growth of chitosan and alginate-based biopolymer membranes for fuel cell applications.

Ethical issues in neonatal and pediatric clinical trials.

PubMed

Laventhal, Naomi; Tarini, Beth A; Lantos, John

2012-10-01

Children have been identified as uniquely vulnerable clinical research subjects since the early 1970s. This article reviews the historical underpinnings of this designation, the current regulatory framework for pediatric and neonatal research, and common problems in pediatric research oversight. It also presents 3 areas of pediatric and neonatal research (genomic screening, healthy children donating stem cells, and therapeutic hypothermia for neonates with hypoxic-ischemic encephalopathy) that highlight contemporary challenges in pediatric research ethics, including balancing risk and benefit, informed consent and assent, and clinical equipoise. Copyright © 2012 Elsevier Inc. All rights reserved.

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

Liphardt, Jan

In April 1953, Watson and Crick largely defined the program of 20th century biology: obtaining the blueprint of life encoded in the DNA. Fifty years later, in 2003, the sequencing of the human genome was completed. Like any major scientific breakthrough, the sequencing of the human genome raised many more questions than it answered. I'll brief you on some of the big open problems in cell and developmental biology, and I'll explain why approaches, tools, and ideas from the physical sciences are currently reshaping biological research. Super-resolution light microscopies are revealing the intricate spatial organization of cells, single-molecule methods showmore » how molecular machines function, and new probes are clarifying the role of mechanical forces in cell and tissue function. At the same time, Physics stands to gain beautiful new problems in soft condensed matter, quantum mechanics, and non-equilibrium thermodynamics.« less

The Intersection of Physics and Biology

ScienceCinema

Liphardt, Jan

2017-12-22

In April 1953, Watson and Crick largely defined the program of 20th century biology: obtaining the blueprint of life encoded in the DNA. Fifty years later, in 2003, the sequencing of the human genome was completed. Like any major scientific breakthrough, the sequencing of the human genome raised many more questions than it answered. I'll brief you on some of the big open problems in cell and developmental biology, and I'll explain why approaches, tools, and ideas from the physical sciences are currently reshaping biological research. Super-resolution light microscopies are revealing the intricate spatial organization of cells, single-molecule methods show how molecular machines function, and new probes are clarifying the role of mechanical forces in cell and tissue function. At the same time, Physics stands to gain beautiful new problems in soft condensed matter, quantum mechanics, and non-equilibrium thermodynamics.

[Embryos and embryo-like entities: problem of definition in the draft of the Swiss embryonic research law].

PubMed

Bürgin, M T; Bürkli, P

2002-11-01

At the end of May 2002, the draft of the Swiss "Federal Act on Research on Surplus Embryos and Embryonic Stem Cells" (EFG, Embryonic Research Act) reached the pre-legislative consultation stage. Under certain conditions, it would allow research on "surplus" embryos from in-vitro fertilization, and the derivation of embryonic stem cells from surplus embryos for research purposes. The EFG draft defines an embryo as "the developing organism from the point of nuclear fusion until the completion of organ development". New technological developments show that embryo-like entities can also be created without nuclear fusion having taken place. It remains unclear how to treat embryonic entities that don't fall under the draft's narrow definition of an embryo. Expanding this definition would be a welcome improvement.

Culture conditions tailored to the cell of origin are critical for maintaining native properties and tumorigenicity of glioma cells.

PubMed

Ledur, Pítia F; Liu, Chong; He, Hua; Harris, Alexandra R; Minussi, Darlan C; Zhou, Hai-Yan; Shaffrey, Mark E; Asthagiri, Ashok; Lopes, Maria Beatriz S; Schiff, David; Lu, Yi-Cheng; Mandell, James W; Lenz, Guido; Zong, Hui

2016-10-01

Cell culture plays a pivotal role in cancer research. However, culture-induced changes in biological properties of tumor cells profoundly affect research reproducibility and translational potential. Establishing culture conditions tailored to the cancer cell of origin could resolve this problem. For glioma research, it has been previously shown that replacing serum with defined growth factors for neural stem cells (NSCs) greatly improved the retention of gene expression profile and tumorigenicity. However, among all molecular subtypes of glioma, our laboratory and others have previously shown that the oligodendrocyte precursor cell (OPC) rather than the NSC serves as the cell of origin for the proneural subtype, raising questions regarding the suitability of NSC-tailored media for culturing proneural glioma cells. OPC-originated mouse glioma cells were cultured in conditions for normal OPCs or NSCs, respectively, for multiple passages. Gene expression profiles, morphologies, tumorigenicity, and drug responsiveness of cultured cells were examined in comparison with freshly isolated tumor cells. OPC media-cultured glioma cells maintained tumorigenicity, gene expression profiles, and morphologies similar to freshly isolated tumor cells. In contrast, NSC-media cultured glioma cells gradually lost their OPC features and most tumor-initiating ability and acquired heightened sensitivity to temozolomide. To improve experimental reproducibility and translational potential of glioma research, it is important to identify the cell of origin, and subsequently apply this knowledge to establish culture conditions that allow the retention of native properties of tumor cells. © The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Space solar cell research: Problems and potential

NASA Technical Reports Server (NTRS)

Flood, D. J.

1986-01-01

The value of a passive, maintenance-free, renewable energy source was apparent in the early days of the space program, and the silicon solar cell was pressed into service. Efficiencies of those early space solar arrays were low, and lifetimes shorter than hoped for, but within a decade significant advances had been made in both areas. Better performance was achieved through improvements in silicon single crystal material, better device designs, and a better understanding of the factors that affect the performance of a solar cell in space. Chief among the latter, particularly for the mid-to-high altitude (HEO) and geosynchronous (GEO) orbits, are the effects of the naturally occurring particulate radiation environment. Although not as broadly important to the photovoltaic community at large as increased efficiency, the topic of radiation damage is critically important to use of solar cells in space, and is a major component of the NASA research program in space photovoltaics. A brief overview of some of the opportunities and challenges for space photovoltaic applications is given, and some of the current research directed at achieving high efficiency and controlling radiation damage in space solar cells is discussed.

Collaborative modelling: the future of computational neuroscience?

PubMed

Davison, Andrew P

2012-01-01

Given the complexity of biological neural circuits and of their component cells and synapses, building and simulating robust, well-validated, detailed models increasingly surpasses the resources of an individual researcher or small research group. In this article, I will briefly review possible solutions to this problem, argue for open, collaborative modelling as the optimal solution for advancing neuroscience knowledge, and identify potential bottlenecks and possible solutions.

Micro and Nano-mediated 3D Cardiac Tissue Engineering

DTIC Science & Technology

2012-09-01

as many forms of heart disease involve stiff scar tissue in the heart. Research Group: Larry Schook Period Sept ’11 to Sept ‘12 Deliverables...to their influence on cell attachment. Modeling disease systems and using recently developed biomaterials on PC biosensors with this new technique...will allow new insight into these problems, enabling researchers to develop more successful therapeutic approaches to clinical disease . VII

Sensing and enumerating rare circulating cells with diffuse light

NASA Astrophysics Data System (ADS)

Zettergren, Eric; Vickers, Dwayne; Niedre, Mark

2011-02-01

Detection and quantification of circulating cells in live animals is a challenging and important problem in many areas of biomedical research. Current methods involve extraction of blood samples and counting of cells ex-vivo. Since only small blood volumes are analyzed at specific time points, monitoring of changes in cell populations over time is difficult and rare cells often escape detection. The goal of this research is to develop a method for enumerating very rare circulating cells in the bloodstream non-invasively. This would have many applications in biomedical research, including monitoring of cancer metastasis and tracking of hematopoietic stem cells. In this work we describe the optical configuration of our instrument which allows fluorescence detection of single cells in diffusive media at the mesoscopic scale. Our instrument design consists of two continuous wave laser diode sources and an 8-channel fiber coupled multi-anode photon counting PMT. Fluorescence detector fibers were arranged circularly around the target in a miniaturized ring configuration. Cell-simulating fluorescent microspheres and fluorescently-labeled cells were passed through a limb mimicking phantom with similar optical properties and background fluorescence as a limb of a mouse. Our data shows that we are able to successfully detect and count these with high quantitative accuracy. Future work includes characterization of our instrument using fluorescently labeled cells in-vivo. If successful, this technique would allow several orders of magnitude in vivo detection sensitivity improvement versus current approaches.

Automated live cell screening system based on a 24-well-microplate with integrated micro fluidics.

PubMed

Lob, V; Geisler, T; Brischwein, M; Uhl, R; Wolf, B

2007-11-01

In research, pharmacologic drug-screening and medical diagnostics, the trend towards the utilization of functional assays using living cells is persisting. Research groups working with living cells are confronted with the problem, that common endpoint measurement methods are not able to map dynamic changes. With consideration of time as a further dimension, the dynamic and networked molecular processes of cells in culture can be monitored. These processes can be investigated by measuring several extracellular parameters. This paper describes a high-content system that provides real-time monitoring data of cell parameters (metabolic and morphological alterations), e.g., upon treatment with drug compounds. Accessible are acidification rates, the oxygen consumption and changes in adhesion forces within 24 cell cultures in parallel. Addressing the rising interest in biomedical and pharmacological high-content screening assays, a concept has been developed, which integrates multi-parametric sensor readout, automated imaging and probe handling into a single embedded platform. A life-maintenance system keeps important environmental parameters (gas, humidity, sterility, temperature) constant.

The "Growing" Reality of the Neurological Complications of Global "Stem Cell Tourism".

PubMed

Julian, Katie; Yuhasz, Nick; Hollingsworth, Ethan; Imitola, Jaime

2018-04-01

"Stem cell tourism" is defined as the unethical practice of offering unproven cellular preparations to patients suffering from various medical conditions. This phenomenon is rising in the field of neurology as patients are requesting information and opportunities for treatment with stem cells for incurable conditions such as multiple sclerosis and amyotrophic lateral sclerosis, despite their clinical research and experimental designation. Here, we review the recent trends in "stem cell tourism" in both the United States and abroad, and discuss the recent reports of neurological complications from these activities. Finally, we frame critical questions for the field of neurology regarding training in the ethical, legal, and societal issues of the global "stem cell tourism," as well as suggest strategies to alleviate this problem. Although there are ongoing legitimate clinical trials with stem cells for neurological diseases, procedures offered by "stem cell clinics" cannot be defined as clinical research. They lack the experimental and state-of-the-art framework defined by peers and the FDA that focus on human research that safeguard the protection of human subjects against economical exploitation, unwanted side effects, and futility of unproven procedures. "Stem cell tourism" ultimately exploits therapeutic hope of patients and families with incurable neurological diseases and can put in danger the legitimacy of stem cell research as a whole. We posit that an improvement in education, regulation, legislation, and involvement of authorities in global health in neurology and neurosurgery is required. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

[Progress of research on the microbial fuel cells in the application of environment pollution treatment--a review].

PubMed

Yang, Yonggang; Sun, Guoping; Xu, Meiying

2010-07-01

Microbial fuel cells (MFCs) are bio-electrochemical reactors that have the capacity to convert chemical energy of biodegradable organic chemicals to electrical energy, and developed rapidly in the past few years. With an increasing concern for energy crisis and environment pollution, MFCs has became a promising technology in the researches of environment pollution treatments and biology electricity. In this paper, we offered a comprehensive review of the recent research progress of MFCs in environment pollution treatment, includes denitrification, desufurization, organic pollutants degradation, heavy metal reduction and landfill leachate treatment. Also, we pointed out the challenges and problems which were bottle necks for a wide application of MFCs and the potential future development.

Cell dynamic morphology classification using deep convolutional neural networks.

PubMed

Li, Heng; Pang, Fengqian; Shi, Yonggang; Liu, Zhiwen

2018-05-15

Cell morphology is often used as a proxy measurement of cell status to understand cell physiology. Hence, interpretation of cell dynamic morphology is a meaningful task in biomedical research. Inspired by the recent success of deep learning, we here explore the application of convolutional neural networks (CNNs) to cell dynamic morphology classification. An innovative strategy for the implementation of CNNs is introduced in this study. Mouse lymphocytes were collected to observe the dynamic morphology, and two datasets were thus set up to investigate the performances of CNNs. Considering the installation of deep learning, the classification problem was simplified from video data to image data, and was then solved by CNNs in a self-taught manner with the generated image data. CNNs were separately performed in three installation scenarios and compared with existing methods. Experimental results demonstrated the potential of CNNs in cell dynamic morphology classification, and validated the effectiveness of the proposed strategy. CNNs were successfully applied to the classification problem, and outperformed the existing methods in the classification accuracy. For the installation of CNNs, transfer learning was proved to be a promising scheme. © 2018 International Society for Advancement of Cytometry. © 2018 International Society for Advancement of Cytometry.

Professional Advanced Research and Analysis

NASA Technical Reports Server (NTRS)

Coulman, George A.

1996-01-01

Reported here is a summary of studies examining some problems in an energy conversion system. Regenerative fuel cell systems have been suggested for future manned space missions, but to meet the needed specific power requirements substantial improvements in the state-of-the-art technologies are needed. Similar improvements are needed, with emphasis on cost reduction in addition to higher conversion efficiency, for fuel cell systems that have potential for terrestrial applications. Polymer Electrolyte Membrane (PEM) fuel cells have been identified as promising candidates for development that would lead to the desired cost reduction and increased efficiency.

Immune checkpoint inhibitors in lung cancer: current status and future directions.

PubMed

Fan, Yun; Mao, Weimin

2017-04-01

Recently, the immune checkpoint inhibitors that target programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) have made a breakthrough in treating advanced non-small cell lung cancer (NSCLC) with the efficacy of approximately 20%; among which, nivolumab has acquired treatment indications in lung squamous cell carcinoma. The inhibitors targeting cytotoxic T lymphocyte associated antigen 4 (CTLA-4) are also undergoing clinical trials. Researches on immune checkpoint inhibitors have been rapidly implemented in a variety of different types of lung cancer, such as small cell lung cancer (SCLC) and locally advanced NSCLC, and these inhibitors began to be applied in combination with some established treatments, including chemotherapy, targeting therapy and radiotherapy. Undoubtedly, the immune checkpoint inhibitors have become a hot spot in the research and treatment of lung cancer. However, many problems wait to be solved, such as searching for ideal biomarkers, constituting the best criteria for curative effect evaluation, exploring different combination treatment models, and clearly understanding the mechanisms of primary or secondary drug resistance. Along with these problems to be successfully solved, the immune checkpoint inhibitors will have more broad applications in lung cancer therapy.

In Vitro Toxicity Screening Technique for Volatile Substances Using Flow-Through System@@

EPA Science Inventory

In 2007, the National Research Council envisioned the need for inexpensive, rapid, cell-based toxicity testing methods relevant to human health. in vitro screening approaches have largely addressed these problems by using robotics and automation. However, the challenge is that ma...

In Vitro Toxicity Screening Technique for Volatile Substances Using Flow-Through System

EPA Science Inventory

In 2007 the National Research Council envisioned the need for inexpensive, rapid, cell based toxicity testing methods relevant to human health. Recent advances in robotics, automation, and miniaturization have been used to address these problems. However, one challenge is that ma...

Childhood Central Nervous System Germ Cell Tumors Treatment

MedlinePlus

... very tired. Having problems with school work. Imaging studies and tests are used to detect (find) and diagnose childhood ... or after starting their cancer treatment. Follow-up tests may be needed. ... trial is a research study meant to help improve current treatments or obtain ...

In Vitro Toxicity Screening Technique for Volatile Substances Using Flow-Through System#

EPA Science Inventory

In 2007 the National Research Council envisioned the need for inexpensive, high throughput, cell based toxicity testing methods relevant to human health. High Throughput Screening (HTS) in vitro screening approaches have addressed these problems by using robotics. However the cha...

Anticancer Activity of Curcumin and Its Analogues: Preclinical and Clinical Studies.

PubMed

Allegra, Alessandro; Innao, Vanessa; Russo, Sabina; Gerace, Demetrio; Alonci, Andrea; Musolino, Caterina

2017-01-02

Curcumin has been shown to have a wide variety of therapeutic effects, ranging from anti-inflammatory, chemopreventive, anti-proliferative, and anti-metastatic. This review provides an overview of the recent research conducted to overcome the problems with the bioavailability of curcumin, and of the preclinical and clinical studies that have reported success in combinatorial strategies coupling curcumin with other treatments. Research on the signaling pathways that curcumin treatment targets shows that it potently acts on major intracellular components involved in key processes such as genomic modulations, cell invasion and cell death pathways. Curcumin is a promising molecule for the prevention and treatment of cancer.

The Tick Cell Biobank: A global resource for in vitro research on ticks, other arthropods and the pathogens they transmit.

PubMed

Bell-Sakyi, Lesley; Darby, Alistair; Baylis, Matthew; Makepeace, Benjamin L

2018-05-31

Tick cell lines are increasingly used in many fields of tick and tick-borne disease research. The Tick Cell Biobank was established in 2009 to facilitate the development and uptake of these unique and valuable resources. As well as serving as a repository for existing and new ixodid and argasid tick cell lines, the Tick Cell Biobank supplies cell lines and training in their maintenance to scientists worldwide and generates novel cultures from tick species not already represented in the collection. Now part of the Institute of Infection and Global Health at the University of Liverpool, the Tick Cell Biobank has embarked on a new phase of activity particularly targeted at research on problems caused by ticks, other arthropods and the diseases they transmit in less-developed, lower- and middle-income countries. We are carrying out genotypic and phenotypic characterisation of selected cell lines derived from tropical tick species. We continue to expand the culture collection, currently comprising 63 cell lines derived from 18 ixodid and argasid tick species and one each from the sand fly Lutzomyia longipalpis and the biting midge Culicoides sonorensis, and are actively engaging with collaborators to obtain starting material for primary cell cultures from other midge species, mites, tsetse flies and bees. Outposts of the Tick Cell Biobank will be set up in Malaysia, Kenya and Brazil to facilitate uptake and exploitation of cell lines and associated training by scientists in these and neighbouring countries. Thus the Tick Cell Biobank will continue to underpin many areas of global research into biology and control of ticks, other arthropods and vector-borne viral, bacterial and protozoan pathogens. Copyright © 2018 The Authors. Published by Elsevier GmbH.. All rights reserved.

HIV infection and women's sexual functioning.

PubMed

Wilson, Tracey E; Jean-Louis, Girardin; Schwartz, Rebecca; Golub, Elizabeth T; Cohen, Mardge H; Maki, Pauline; Greenblatt, Ruth; Massad, L Stewart; Robison, Esther; Goparaju, Lakshmi; Lindau, Stacy

2010-08-01

To compare sexual problems among HIV-positive and HIV-negative women and describe clinical and psychosocial factors associated with these problems. Data were collected during a study visit of the Women's Interagency HIV Study (WIHS). The WIHS studies the natural and treated history of HIV among women in the United States. Between October 01, 2006, and March 30, 2007, 1805 women (1279 HIV positive and 526 HIV negative) completed a study visit that included administration of the Female Sexual Function Index. In addition, the visit included completion of standardized interviewer-administered surveys, physical and gynecological examinations, and blood sample collection. Women with HIV reported greater sexual problems than did those without HIV. Women also reported lower sexual function if they were classified as menopausal, had symptoms indicative of depression, or if they reported not being in a relationship. CD4 cell count was associated with Female Sexual Function Index scores, such that those with CD4

HIV Infection and Women’s Sexual Functioning

PubMed Central

Wilson, Tracey E.; Jean-Louis, Girardin; Schwartz, Rebecca; Golub, Elizabeth T.; Cohen, Mardge H.; Maki, Pauline; Greenblatt, Ruth; Massad, L. Stewart; Robison, Esther; Goparaju, Lakshmi; Lindau, Stacy

2010-01-01

Objective To compare sexual problems among HIV-positive and HIV-negative women, and describe clinical and psychosocial factors associated with these problems. Design Data were collected during a study visit of the Women’s Interagency HIV Study (WIHS). The WIHS studies the natural and treated history of HIV among women in the United States. Methods Between 10/01/2006 and 3/30/2007, 1,805 women (1,279 HIV-positive and 526 HIV-negative) completed a study visit that included administration of the Female Sexual Function Index (FSFI). In addition, the visit included completion of standardized, interviewer-administered surveys, physical and gynecological examinations, and blood sample collection. Results Women with HIV reported greater sexual problems than did those without HIV. Women also reported lower sexual function if they were classified as menopausal, had symptoms indicative of depression, or if they reported not being in a relationship. CD4+ cell count was associated with FSFI scores, such that those with CD4 ≤199 cells/µL reported lower functioning as compared to those whose cell count was 200 or higher. Conclusions Given research documenting relationships between self-reported sexual problems and both clinical diagnoses of sexual dysfunction and women’s quality of life, greater attention to this issue as a potential component of women’s overall HIV care is warranted. PMID:20179602

Tiny cells meet big questions: a closer look at bacterial cell biology.

PubMed

Goley, Erin D

2013-04-01

While studying actin assembly as a graduate student with Matt Welch at the University of California at Berkeley, my interest was piqued by reports of surprising observations in bacteria: the identification of numerous cytoskeletal proteins, actin homologues fulfilling spindle-like functions, and even the presence of membrane-bound organelles. Curiosity about these phenomena drew me to Lucy Shapiro's lab at Stanford University for my postdoctoral research. In the Shapiro lab, and now in my lab at Johns Hopkins, I have focused on investigating the mechanisms of bacterial cytokinesis. Spending time as both a eukaryotic cell biologist and a bacterial cell biologist has convinced me that bacterial cells present the same questions as eukaryotic cells: How are chromosomes organized and accurately segregated? How is force generated for cytokinesis? How is polarity established? How are signals transduced within and between cells? These problems are conceptually similar between eukaryotes and bacteria, although their solutions can differ significantly in specifics. In this Perspective, I provide a broad view of cell biological phenomena in bacteria, the technical challenges facing those of us who peer into bacterial cells, and areas of common ground as research in eukaryotic and bacterial cell biology moves forward.

Splenic red pulp macrophages are intrinsically superparamagnetic and contaminate magnetic cell isolates.

PubMed

Franken, Lars; Klein, Marika; Spasova, Marina; Elsukova, Anna; Wiedwald, Ulf; Welz, Meike; Knolle, Percy; Farle, Michael; Limmer, Andreas; Kurts, Christian

2015-08-11

A main function of splenic red pulp macrophages is the degradation of damaged or aged erythrocytes. Here we show that these macrophages accumulate ferrimagnetic iron oxides that render them intrinsically superparamagnetic. Consequently, these cells routinely contaminate splenic cell isolates obtained with the use of MCS, a technique that has been widely used in immunological research for decades. These contaminations can profoundly alter experimental results. In mice deficient for the transcription factor SpiC, which lack red pulp macrophages, liver Kupffer cells take over the task of erythrocyte degradation and become superparamagnetic. We describe a simple additional magnetic separation step that avoids this problem and substantially improves purity of magnetic cell isolates from the spleen.

Polymer Formulations for Cartilage Repair

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

Gutowska, Anna; Jasionowski, Marek; Morris, J. E.

2001-05-15

Regeneration of destroyed articular cartilage can be induced by transplantation of cartilage cells into a defect. The best results are obtained with the use of autologus cells. However, obtaining large amounts of autologus cartilage cells causes a problem of creating a large cartilage defect in a donor site. Techniques are currently being developed to harvest a small number of cells and propagate them in vitro. It is a challenging task, however, due to the fact that ordinarily, in a cell culture on flat surfaces, chondrocytes do not maintain their in vivo phenotype and irreversibly diminish or cease the synthesis ofmore » aggregating proteoglycans. Therefore, the research is continuing to develop culture conditions for chondrocytes with the preserved phenotype.« less

Recent researches in airship construction II : bending stresses on an airship in flight

NASA Technical Reports Server (NTRS)

Naatz, H

1924-01-01

The first part of this report shows the differences between commercial and war airships and then goes on to show how some of the problems were solved. Their thorough investigations of these problems finally enabled the Schutte-Lanz Company to construct bulkhead diagrams for determining the buoyancy of airships, by means of which the size of each cell was established. These diagrams were derived from bulkhead diagrams employed in ship designing and are used in a similar manner.

Regeneration of articular cartilage by adipose tissue derived mesenchymal stem cells: perspectives from stem cell biology and molecular medicine.

PubMed

Wu, Ling; Cai, Xiaoxiao; Zhang, Shu; Karperien, Marcel; Lin, Yunfeng

2013-05-01

Adipose-derived stem cells (ASCs) have been discovered for more than a decade. Due to the large numbers of cells that can be harvested with relatively little donor morbidity, they are considered to be an attractive alternative to bone marrow derived mesenchymal stem cells. Consequently, isolation and differentiation of ASCs draw great attention in the research of tissue engineering and regenerative medicine. Cartilage defects cause big therapeutic problems because of their low self-repair capacity. Application of ASCs in cartilage regeneration gives hope to treat cartilage defects with autologous stem cells. In recent years, a lot of studies have been performed to test the possibility of using ASCs to re-construct damaged cartilage tissue. In this article, we have reviewed the most up-to-date articles utilizing ASCs for cartilage regeneration in basic and translational research. Our topic covers differentiation of adipose tissue derived mesenchymal stem cells into chondrocytes, increased cartilage formation by co-culture of ASCs with chondrocytes and enhancing chondrogenic differentiation of ASCs by gene manipulation. Copyright © 2012 Wiley Periodicals, Inc.

The potential of induced pluripotent stem cells as a tool to study skeletal dysplasias and cartilage-related pathologic conditions.

PubMed

Liu, H; Yang, L; Yu, F F; Wang, S; Wu, C; Qu, C; Lammi, M J; Guo, X

2017-05-01

The development of induced pluripotent stem cells (iPSCs) technology has opened up new horizons for development of new research tools especially for skeletal dysplasias, which often lack human disease models. Regenerative medicine and tissue engineering could be the next areas to benefit from refinement of iPSC methods to repair focal cartilage defects, while applications for osteoarthritis (OA) and drug screening have evolved rather slowly. Although the advances in iPSC research of skeletal dysplasias and repair of focal cartilage lesions are not directly relevant to OA, they can be considered to pave the way to future prospects and solutions to OA research, too. The same problems which face the present cell-based treatments of cartilage injuries concern also the iPSC-based ones. However, established iPSC lines, which have no genomic aberrations and which efficiently differentiate into extracellular matrix secreting chondrocytes, could be an invaluable cell source for cell transplantations in the future. The safety issues concerning the recipient risks of teratoma formation and immune response still have to be solved before the potential use of iPSCs in cartilage repair of focal cartilage defects and OA. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

T-cell and natural killer cell therapies for hematologic malignancies after hematopoietic stem cell transplantation: enhancing the graft-versus-leukemia effect

PubMed Central

Cruz, C. Russell; Bollard, Catherine M.

2015-01-01

Hematopoietic stem cell transplantation has revolutionized the treatment of hematologic malignancies, but infection, graft-versus-host disease and relapse are still important problems. Calcineurin inhibitors, T-cell depletion strategies, and immunomodulators have helped to prevent graft-versus-host disease, but have a negative impact on the graft-versus-leukemia effect. T cells and natural killer cells are both thought to be important in the graft-versus-leukemia effect, and both cell types are amenable to ex vivo manipulation and clinical manufacture, making them versatile immunotherapeutics. We provide an overview of these immunotherapeutic strategies following hematopoietic stem cell transplantation, with discussions centered on natural killer and T-cell biology. We discuss the contributions of each cell type to graft-versus-leukemia effects, as well as the current research directions in the field as related to adoptive cell therapy after hematopoietic stem cell transplantation. PMID:26034113

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

PubMed

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

2017-01-01

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

Angiogenesis Research to Improve Therapies for Vascular Leak Syndromes, Intra-abdominal Adhesions, and Arterial Injuries

DTIC Science & Technology

2008-04-01

small-cell lung cancer; TFP1, transferrin pseudogene 1; TGFβ, transforming growth factor-β; TNF, tumour- necrosis factor; uPA, urokinase-type plasminogen...Cell 79, 315–328 (1994). 23. Frater-Schroder, M., Risau, W., Hallmann, R., Gautschi, P. & Bohlen, P. Tumor necrosis factor type α, a potent inhibitor...relatively thin (skin) or avascular (cartilage) tissues, where post- implantation vascularization from the host is sufficient. To overcome the problem

Implicit Plasma Kinetic Simulation Using The Jacobian-Free Newton-Krylov Method

NASA Astrophysics Data System (ADS)

Taitano, William; Knoll, Dana; Chacon, Luis

2009-11-01

The use of fully implicit time integration methods in kinetic simulation is still area of algorithmic research. A brute-force approach to simultaneously including the field equations and the particle distribution function would result in an intractable linear algebra problem. A number of algorithms have been put forward which rely on an extrapolation in time. They can be thought of as linearly implicit methods or one-step Newton methods. However, issues related to time accuracy of these methods still remain. We are pursuing a route to implicit plasma kinetic simulation which eliminates extrapolation, eliminates phase-space from the linear algebra problem, and converges the entire nonlinear system within a time step. We accomplish all this using the Jacobian-Free Newton-Krylov algorithm. The original research along these lines considered particle methods to advance the distribution function [1]. In the current research we are advancing the Vlasov equations on a grid. Results will be presented which highlight algorithmic details for single species electrostatic problems and coupled ion-electron electrostatic problems. [4pt] [1] H. J. Kim, L. Chac'on, G. Lapenta, ``Fully implicit particle in cell algorithm,'' 47th Annual Meeting of the Division of Plasma Physics, Oct. 24-28, 2005, Denver, CO

Anticancer activity of Sargassum oligocystum water extract against human cancer cell lines.

PubMed

Zandi, K; Ahmadzadeh, S; Tajbakhsh, S; Rastian, Z; Yousefi, F; Farshadpour, F; Sartavi, K

2010-08-01

Antitumor drug resistance and side effects of antitumor compounds are the most common problems in medicine. Therefore, finding new antitumor agents with low side effects could be interesting. This study was designed to assay antitumor activity of the extract from brown alga Sargassum oligocystum, gathered from Persian Gulf seashore, against K562 and Daudi human cancer cell lines. The research was performed as an in vitro study. The effect of the alga extract on proliferation of cell lines were measured by two methods: MTT assay and trypan blue exclusion test. The most effective antitumor activity has been shown at concentrations 500 microg/ml and 400 microg/ml of the alga extract against Daudi and K562 cell lines, respectively. The results showed that the extracts of brown alga Sargassum oligocystum have remarkable antitumor activity against K562 and Daudi cell lines. It is justified to be suggested for further research such as algal extract fractionation and purification and in vivo studies in order to formulate natural compounds with antitumor activities.

Translational Cellular Research on the International Space Station

NASA Technical Reports Server (NTRS)

Love, John; Cooley, Vic

2016-01-01

The emerging field of Translational Research aims to coalesce interdisciplinary findings from basic science for biomedical applications. To complement spaceflight research using human subjects, translational studies can be designed to address aspects of space-related human health risks and help develop countermeasures to prevent or mitigate them, with therapeutical benefits for analogous conditions experienced on Earth. Translational research with cells and model organisms is being conducted onboard the International Space Station (ISS) in connection with various human systems impacted by spaceflight, such as the cardiovascular, musculoskeletal, and immune systems. Examples of recent cell-based translational investigations on the ISS include the following. The JAXA investigation Cell Mechanosensing seeks to identify gravity sensors in skeletal muscle cells to develop muscle atrophy countermeasures by analyzing tension fluctuations in the plasma membrane, which changes the expression of key proteins and genes. Earth applications of this study include therapeutic approaches for some forms of muscular dystrophy, which appear to parallel aspects of muscle wasting in space. Spheroids is an ESA investigation examining the system of endothelial cells lining the inner surface of all blood vessels in terms of vessel formation, cellular proliferation, and programmed cell death, because injury to the endothelium has been implicated as underpinning various cardiovascular and musculoskeletal problems arising during spaceflight. Since endothelial cells are involved in the functional integrity of the vascular wall, this research has applications to Earth diseases such as atherosclerosis, diabetes, and hypertension. The goal of the T-Cell Activation in Aging NASA investigation is to understand human immune system depression in microgravity by identifying gene expression patterns of candidate molecular regulators, which will provide further insight into factors that may play a critical role in immune function loss during aging. In addition, Omics investigations with cells have synergistic applications ranging from the evaluation of pharmacological countermeasures to drug discovery. Thus, cell-based translational research onboard the ISS is bidirectionally bridging cutting-edge cellular and molecular approaches with space bioastronautics and human health methodologies on Earth.

Investigating the role of retinal Müller cells with approaches in genetics and cell biology.

PubMed

Fu, Suhua; Zhu, Meili; Ash, John D; Wang, Yunchang; Le, Yun-Zheng

2014-01-01

Müller cells are major macroglia and play many essential roles as a supporting cell in the retina. As Müller cells only constitute a small portion of retinal cells, investigating the role of Müller glia in retinal biology and diseases is particularly challenging. To overcome this problem, we first generated a Cre/lox-based conditional gene targeting system that permits the genetic manipulation and functional dissection of gene of interests in Müller cells. To investigate diabetes-induced alteration of Müller cells, we recently adopted methods to analyze Müller cells survival/death in vitro and in vivo. We also used normal and genetically altered primary cell cultures to reveal the mechanistic insights for Müller cells in biological and disease processes. In this article, we will discuss the applications and limitations of these methodologies, which may be useful for research in retinal Müller cell biology and pathophysiology.

Current Psychopathology in Previously Assaulted Older Adults

ERIC Educational Resources Information Center

Acierno, Ron; Lawyer, Steven R.; Rheingold, Alyssa; Kilpatrick, Dean G.; Resnick, Heidi S.; Saunders, Benjamin E.

2007-01-01

Older adult women age 55+ years (N = 549) were interviewed as part of a population-based epidemiological research study of lifetime experiences with physical and sexual assault and current mental health problems. Although overall rates of psychopathology were low, producing very small cells for comparison, women who reported experiencing physical…

Aerodynamics of Engine-Airframe Interaction

NASA Technical Reports Server (NTRS)

Caughey, D. A.

1986-01-01

The report describes progress in research directed towards the efficient solution of the inviscid Euler and Reynolds-averaged Navier-Stokes equations for transonic flows through engine inlets, and past complete aircraft configurations, with emphasis on the flowfields in the vicinity of engine inlets. The research focusses upon the development of solution-adaptive grid procedures for these problems, and the development of multi-grid algorithms in conjunction with both, implicit and explicit time-stepping schemes for the solution of three-dimensional problems. The work includes further development of mesh systems suitable for inlet and wing-fuselage-inlet geometries using a variational approach. Work during this reporting period concentrated upon two-dimensional problems, and has been in two general areas: (1) the development of solution-adaptive procedures to cluster the grid cells in regions of high (truncation) error;and (2) the development of a multigrid scheme for solution of the two-dimensional Euler equations using a diagonalized alternating direction implicit (ADI) smoothing algorithm.

Enhanced conversion of induced neuronal cells (iN cells) from human fibroblasts: utility in uncovering cellular deficits in mental illness-associated chromosomal abnormalities

PubMed Central

Passeri, Eleonora; Wilson, Ashley M.; Primerano, Amedeo; Kondo, Mari A.; Sengupta, Srona; Srivastava, Rupali; Koga, Minori; Obie, Cassandra; Zandi, Peter P.; Goes, Fernando S.; Valle, David; Rapoport, Judith L.; Sawa, Akira; Kano, Shin-ichi; Ishizuka, Koko

2016-01-01

The novel technology of induced neuronal cells (iN cells) is promising for translational neuroscience, as it allows the conversion of human fibroblasts into cells with postmitotic neuronal traits. However, a major technical barrier is the low conversion rate. To overcome this problem, we optimized the conversion media. Using our improved formulation, we studied how major mental illness-associated chromosomal abnormalities may impact the characteristics of iN cells. We demonstrated that our new iN cell culture protocol enabled us to obtain more precise measurement of neuronal cellular phenotypes than previous iN cell methods. Thus, this iN cell culture provides a platform to efficiently obtain possible cellular phenotypes caused by genetic differences, which can be more thoroughly studied in research using other human cell models such as induced pluripotent stem cells. PMID:26260244

Mix-ups and mycoplasma: the enemies within.

PubMed

Drexler, Hans G; Uphoff, Cord C; Dirks, Willy G; MacLeod, Roderick A F

2002-04-01

Human leukemia-lymphoma (LL) cell lines represent important tools for experimental research. Among the various problems associated with cell lines, the two most common concern contaminations: (1) cross-contamination with unrelated cells and (2) contamination with microorganisms, in particular mycoplasma. The bad news is that about one-third of the cell lines are either cross-contaminated or mycoplasma-infected or both. The good news is that there are means to recognize and overcome these problems. In cases where, during attempts to establish new LL cell lines, primary LL cultures are cross-contaminated with continuous cell lines, intended new cell lines simply cannot be established ("early" cross-contamination). In cases of "late" cross-contamination of existing LL cell lines where the intrusive cells have a growth advantage, the original ("uncontaminated") cell lines may still be available elsewhere. DNA fingerprinting and cytogenetic analysis appear to be the most suitable approaches to detect cross-contaminations and to authenticate LL cell lines. A different but related aspect of "false" LL cell lines is the frequent misclassification of cell lines whereby the actual cell type of the cell line does not correspond to the purported model character of the cell line. Mycoplasma infection can have a multitude of effects on the eukaryotic cells which, due to the variety of infecting mycoplasma species and many other contributing parameters, cannot be predicted, rendering resulting data questionable at best. Practical procedures for the detection and elimination of mycoplasma contamination have been developed. Diagnostic and preventive strategies in order to hem the alarming increase in "false" and mycoplasma-positive LL cell lines are recommended.

Combining FMEA with DEMATEL models to solve production process problems

PubMed Central

Tsai, Sang-Bing; Zhou, Jie; Gao, Yang; Wang, Jiangtao; Li, Guodong; Zheng, Yuxiang; Ren, Peng; Xu, Wei

2017-01-01

Failure mode and effects analysis (FMEA) is an analysis tool for identifying and preventing flaws or defects in products during the design and process planning stage, preventing the repeated occurrence of problems, reducing the effects of these problems, enhancing product quality and reliability, saving costs, and improving competitiveness. However, FMEA can only analyze one influence factor according to its priority, rendering this method ineffective for systems containing multiple FMs whose effects are simultaneous or interact with one another. Accordingly, when FMEA fails to identify the influence factors and the factors being influenced, the most crucial problems may be placed in lower priority or remain unresolved. Decision-Making Trial and Evaluation Laboratory (DEMATEL) facilitates the determination of cause and effect factors; by identifying the causal factors that should be prioritized, prompt and effective solutions to core problems can be derived, thereby enhancing performance. Using the photovoltaic cell manufacturing industry in China as the research target, the present study combined FMEA with DEMATEL to amend the flaws of FMEA and enhance its effectiveness. First, FMEA was used to identify items requiring improvement. Then, DEMATEL was employed to examine the interactive effects and causal relationships of these items. Finally, the solutions to the problems were prioritized. The proposed method effectively combined the advantages of FMEA and DEMATEL to facilitate the identification of core problems and prioritization of solutions in the Chinese photovoltaic cell industry. PMID:28837663

Combining FMEA with DEMATEL models to solve production process problems.

PubMed

Tsai, Sang-Bing; Zhou, Jie; Gao, Yang; Wang, Jiangtao; Li, Guodong; Zheng, Yuxiang; Ren, Peng; Xu, Wei

2017-01-01

Failure mode and effects analysis (FMEA) is an analysis tool for identifying and preventing flaws or defects in products during the design and process planning stage, preventing the repeated occurrence of problems, reducing the effects of these problems, enhancing product quality and reliability, saving costs, and improving competitiveness. However, FMEA can only analyze one influence factor according to its priority, rendering this method ineffective for systems containing multiple FMs whose effects are simultaneous or interact with one another. Accordingly, when FMEA fails to identify the influence factors and the factors being influenced, the most crucial problems may be placed in lower priority or remain unresolved. Decision-Making Trial and Evaluation Laboratory (DEMATEL) facilitates the determination of cause and effect factors; by identifying the causal factors that should be prioritized, prompt and effective solutions to core problems can be derived, thereby enhancing performance. Using the photovoltaic cell manufacturing industry in China as the research target, the present study combined FMEA with DEMATEL to amend the flaws of FMEA and enhance its effectiveness. First, FMEA was used to identify items requiring improvement. Then, DEMATEL was employed to examine the interactive effects and causal relationships of these items. Finally, the solutions to the problems were prioritized. The proposed method effectively combined the advantages of FMEA and DEMATEL to facilitate the identification of core problems and prioritization of solutions in the Chinese photovoltaic cell industry.

[Research on the eventual cross-reactivity of anti-Wr(a) with various viral, bacterial and mycotic antigenes (author's transl)].

PubMed

Garelli, S; Valbonesi, M; Picerno, G; Vazzana, A

1978-09-01

Among the sera of 1011 blood donors, they have been collected 34 anti-Wr(a) antibodies. By IgG antiglobulin test, the titer was 1/8 or more in 21 sera. After absorption on viral, bacterial and mycotic antigens, the sera were still reactive with Wr(a) + red blood cells. These results show that no tested antigen is cross-reactive with Wr(a) antigen. However, the AA. suggest that the research of a widley diffused antigen, cross-reactive with Wr(a) + red blood cells, is a valuable approach to the problem of IgG anti-Wr(a) antibodies in normal, never transfused blood donors.

Algorithms for optimization of the transport system in living and artificial cells.

PubMed

Melkikh, A V; Sutormina, M I

2011-06-01

An optimization of the transport system in a cell has been considered from the viewpoint of the operations research. Algorithms for an optimization of the transport system of a cell in terms of both the efficiency and a weak sensitivity of a cell to environmental changes have been proposed. The switching of various systems of transport is considered as the mechanism of weak sensitivity of a cell to changes in environment. The use of the algorithms for an optimization of a cardiac cell has been considered by way of example. We received theoretically for a cell of a cardiac muscle that at the increase of potassium concentration in the environment switching of transport systems for this ion takes place. This conclusion qualitatively coincides with experiments. The problem of synthesizing an optimal system in an artificial cell has been stated.

Analysis of Invasion Dynamics of Matrix-Embedded Cells in a Multisample Format.

PubMed

Van Troys, Marleen; Masuzzo, Paola; Huyck, Lynn; Bakkali, Karima; Waterschoot, Davy; Martens, Lennart; Ampe, Christophe

2018-01-01

In vitro tests of cancer cell invasion are the "first line" tools of preclinical researchers for screening the multitude of chemical compounds or cell perturbations that may aid in halting or treating cancer malignancy. In order to have predictive value or to contribute to designing personalized treatment regimes, these tests need to take into account the cancer cell environment and measure effects on invasion in sufficient detail. The in vitro invasion assays presented here are a trade-off between feasibility in a multisample format and mimicking the complexity of the tumor microenvironment. They allow testing multiple samples and conditions in parallel using 3D-matrix-embedded cells and deal with the heterogeneous behavior of an invading cell population in time. We describe the steps to take, the technical problems to tackle and useful software tools for the entire workflow: from the experimental setup to the quantification of the invasive capacity of the cells. The protocol is intended to guide researchers to standardize experimental set-ups and to annotate their invasion experiments in sufficient detail. In addition, it provides options for image processing and a solution for storage, visualization, quantitative analysis, and multisample comparison of acquired cell invasion data.

Cell-assisted lipotransfer in the clinical treatment of facial soft tissue deformity

PubMed Central

Ma, Li; Wen, Huicai; Jian, Xueping; Liao, Huaiwei; Sui, Yunpeng; Liu, Yanping; Xu, Guizhen

2015-01-01

Cosmetic surgeons have experimented with a variety of substances to improve soft tissue deformities of the face. Autologous fat grafting provides significant advantages over other modalities because it leaves no scar, is easy to use and is well tolerated by most patients. Autologous fat grafting has become one of the most popular techniques in the field of facial plastic surgery. Unfortunately, there are still two major problems affecting survival rate and development: revascularization after transplantion; and cell reservation proliferation and survival. Since Zuk and Yosra developed a technology based on adipose-derived stem cells and cell-assisted lipotrophy, researchers have hoped that this technology would promote the survival and reduce the absorption of grafted fat cells. Autologous adipose-derived stem cells may have great potential in skin repair applications, aged skin rejuvenation and other aging-related skin lesion treatments. Recently, the study of adipose-derived stem cells has gained increased attention. More researchers have started to adopt this technology in the clinical treatment of facial soft tissue deformity. The present article reviews the history of facial soft tissue augmentation and the advent of adipose-derived stem cells in the area of the clinical treatment of facial soft tissue deformity. PMID:26361629

The costs of using unauthenticated, over-passaged cell lines: how much more data do we need?

PubMed

Hughes, Peyton; Marshall, Damian; Reid, Yvonne; Parkes, Helen; Gelber, Cohava

2007-11-01

Increasing data demonstrate that cellular cross-contamination, misidentified cell lines, and the use of cultures at high-passage levels contribute to the generation of erroneous and misleading results as well as wasted research funds. Contamination of cell lines by other lines has been recognized and documented back to the 1950s. Based on submissions to major cell repositories in the last decade, it is estimated that between 18% and 36% of cell lines may be contaminated or misidentified. More recently, problems surrounding practices of over-subculturing cells are being identified. As a result of selective pressures and genetic drift, cell lines, when kept in culture too long, exhibit reduced or altered key functions and often no longer represent reliable models of their original source material. A review of papers showing significant experimental variances between low- and high-passage cell culture numbers, as well as contaminated lines, makes a strong case for using verified, tested cell lines at low- or defined passage numbers. In the absence of cell culture guidelines, mandates from the National Institutes of Health (NIH) and other funding agencies or journal requirements, it becomes the responsibility of the scientific community to perform due diligence to ensure the integrity of cell cultures used in research.

How Not To Drown in Data: A Guide for Biomaterial Engineers.

PubMed

Vasilevich, Aliaksei S; Carlier, Aurélie; de Boer, Jan; Singh, Shantanu

2017-08-01

High-throughput assays that produce hundreds of measurements per sample are powerful tools for quantifying cell-material interactions. With advances in automation and miniaturization in material fabrication, hundreds of biomaterial samples can be rapidly produced, which can then be characterized using these assays. However, the resulting deluge of data can be overwhelming. To the rescue are computational methods that are well suited to these problems. Machine learning techniques provide a vast array of tools to make predictions about cell-material interactions and to find patterns in cellular responses. Computational simulations allow researchers to pose and test hypotheses and perform experiments in silico. This review describes approaches from these two domains that can be brought to bear on the problem of analyzing biomaterial screening data. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of the lithium/thionyl chloride battery

NASA Technical Reports Server (NTRS)

White, Ralph E.

1987-01-01

The progress which has been made in modeling the lithium/thionyl chloride cell over the past year and proposed research for the coming year are discussed. A one-dimensional mathematical model for a lithium/thionyl chloride cell has been developed and used to investigate methods of improving cell performance. During the course of the work a problem was detected with the banded solver being used. It was replaced with one more reliable. Future work may take one of two directions. The one-dimensional model could be augmented to include additional features and to investigate in more detail the cell temperature behavior, or a simplified two-dimensional model for the spirally wound design of this battery could be developed to investigate the heat flow within the cell.

Circulating Tumor Cells: From Theory to Nanotechnology-Based Detection

PubMed Central

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

2017-01-01

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

[Process in menstrual blood-derived mesenchymal stem cells for treatment of central nervous system diseases].

PubMed

Liu, Mengmeng; Cheng, Xinran; Li, Kaikai; Xu, Mingrui; Wu, Yongji; Wang, Mengli; Zhang, Qianru; Yan, Wenyong; Luo, Chang; Zhao, Shanting

2018-05-25

Stem cell research has become a frontier in the field of life sciences, and provides an ideal model for exploring developmental biology problems such as embryogenesis, histiocytosis, and gene expression regulation, as well as opens up new doors for clinical tissue defective and inheritance diseases. Among them, menstrual blood-derived stem cells (MenSCs) are characterized by wide source, multi-directional differentiation potential, low immune rejection characteristics. Thus, MenSCs can achieve individual treatment and have the most advantage of the clinical application. The central nervous system, including brain and spinal cord, is susceptible to injury. And lethality and morbidity of them tops the list of all types of trauma. Compared to peripheral nervous system, recovery of central nervous system after damage remains extremely hard. However, the treatment of stem cells, especially MenSCs, is expected to solve this problem. Therefore, biological characteristics of MenSCs and their treatment in the respect of central nervous system diseases have been reviewed at home and abroad in recent years, so as to provide reference for the treatment of central nervous system diseases.

Biology of lung cancer: genetic mutation, epithelial-mesenchymal transition, and cancer stem cells.

PubMed

Aoi, Takashi

2016-09-01

At present, most cases of unresectable cancer cannot be cured. Genetic mutations, EMT, and cancer stem cells are three major issues linked to poor prognosis in such cases, all connected by inter- and intra-tumor heterogeneity. Issues on inter-/intra-tumor heterogeneity of genetic mutation could be resolved with recent and future technologies of deep sequencers, whereas, regarding such issues as the "same genome, different epigenome/phenotype", we expect to solve many of these problems in the future through further research in stem cell biology. We herein review and discuss the three major issues in the biology of cancers, especially from the standpoint of stem cell biology.

US Army Medical Bioengineering Research and Development Laboratory Annual Progress Report for FY 83.

DTIC Science & Technology

1983-10-01

Army consumes is chlorinated. Also, the water from Army wastewater treatment plants is chlorinated before it is returned to the environment.I Because...12K; CY - K; BY - OK PROBLEM DEFINITION: Chlorination of drinking water and of effluents from wastewater treatment plants is standard practice employed...FY81 indicated no research - activity on this type of photocell. Materials and chemicals have been ordered and assembled. A preliminary cell has been

Comparison of fundamental physical properties of the model cells (protocells) and the living cells reveals the need in protophysiology

NASA Astrophysics Data System (ADS)

Matveev, V. V.

2017-01-01

A hypothesis is proposed about potassium ponds being the cradles of life enriches the gamut of ideas about the possible conditions of pre-biological evolution on the primeval Earth, but does not bring us closer to solving the real problem of the origin of life. The gist of the matter lies in the mechanism of making a delimitation between two environments - the intracellular environment and the habitat of protocells. Since the sodium-potassium pump (Na+/K+-ATPase) was discovered, no molecular model has been proposed for a predecessor of the modern sodium pump. This has brought into life the idea of the potassium pond, wherein protocells would not need a sodium pump. However, current notions of the operation of living cells come into conflict with even physical laws when trying to use them to explain the origin and functioning of protocells. Thus, habitual explanations of the physical properties of living cells have become inapplicable to explain the corresponding properties of Sidney Fox's microspheres. Likewise, existing approaches to solving the problem of the origin of life do not see the need for the comparative study of living cells and cell models, assemblies of biological and artificial small molecules and macromolecules under physical conditions conducive to the origin of life. The time has come to conduct comprehensive research into the fundamental physical properties of protocells and create a new discipline - protocell physiology or protophysiology - which should bring us much closer to solving the problem of the origin of life.

Incident Involving 30-Ah Li-ion Cell at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Bennett, William

2006-01-01

The key lesson learned from the February 17, 2006 cell explosion incident is that PC-based test-systems, even those having built-in watchdog monitors, can lose control and malfunction. In the case of lithiumion cell/battery testing, the stored energy can be released explosively causing considerable injury and damage to facilities. The investigation showed that although the Arbin system has a built-in watchdog monitor, the circumstances of the incident defeated the action of the watchdog and allowed the cycler to continue operation without control. An upgrade to the most recent version of Arbin software (version 4) was provided as a fix to the presumed control problem. This upgrade included newer EPROM s for the cycler microprocessor. Investigation revealed that similar incidents have occurred at other NASA centers with a variety of PC-based test instruments. JPL suffered an incident with Maccor testers and the GRC fuel cell group observed similar problems with LabView software. This is not exclusively an Arbin problem, but an issue with all PC-based systems. In this incident, it was fortunate that the event occurred after-hours with no-one in the room. The facility arrangement placed control consoles adjacent to the test chamber doors. Had someone been in the room during the event, they would have been exposed to hot debris and toxic combustion products. It was also fortunate that the exploded cell stayed inside the chamber after the door was forced open. If the cell had been ejected into the room it could have caused serious facility damage by impact and possibly caused a fire in the facility.

Learning Nucleic Acids Solving by Bioinformatics Problems

ERIC Educational Resources Information Center

Nunes, Rhewter; de Almeida Júnior, Edivaldo Barbosa; de Menezes, Ivandilson Pessoa Pinto; Malafaia, Guilherme

2015-01-01

The article describes the development of a new approach to teach molecular biology to undergraduate biology students. The 34 students who participated in this research belonged to the first period of the Biological Sciences teaching course of the Instituto Federal Goiano at Urutaí Campus, Brazil. They were registered in Cell Biology in the first…

Transfer of space technology to industry

NASA Technical Reports Server (NTRS)

Hamilton, J. T.

1974-01-01

Some of the most significant applications of the NASA aerospace technology transfer to industry and other government agencies are briefly outlined. The technology utilization program encompasses computer programs for structural problems, life support systems, fuel cell development, and rechargeable cardiac pacemakers as well as reliability and quality research for oil recovery operations and pollution control.

White blood cell segmentation by circle detection using electromagnetism-like optimization.

PubMed

Cuevas, Erik; Oliva, Diego; Díaz, Margarita; Zaldivar, Daniel; Pérez-Cisneros, Marco; Pajares, Gonzalo

2013-01-01

Medical imaging is a relevant field of application of image processing algorithms. In particular, the analysis of white blood cell (WBC) images has engaged researchers from fields of medicine and computer vision alike. Since WBCs can be approximated by a quasicircular form, a circular detector algorithm may be successfully applied. This paper presents an algorithm for the automatic detection of white blood cells embedded into complicated and cluttered smear images that considers the complete process as a circle detection problem. The approach is based on a nature-inspired technique called the electromagnetism-like optimization (EMO) algorithm which is a heuristic method that follows electromagnetism principles for solving complex optimization problems. The proposed approach uses an objective function which measures the resemblance of a candidate circle to an actual WBC. Guided by the values of such objective function, the set of encoded candidate circles are evolved by using EMO, so that they can fit into the actual blood cells contained in the edge map of the image. Experimental results from blood cell images with a varying range of complexity are included to validate the efficiency of the proposed technique regarding detection, robustness, and stability.

White Blood Cell Segmentation by Circle Detection Using Electromagnetism-Like Optimization

PubMed Central

Oliva, Diego; Díaz, Margarita; Zaldivar, Daniel; Pérez-Cisneros, Marco; Pajares, Gonzalo

2013-01-01

Medical imaging is a relevant field of application of image processing algorithms. In particular, the analysis of white blood cell (WBC) images has engaged researchers from fields of medicine and computer vision alike. Since WBCs can be approximated by a quasicircular form, a circular detector algorithm may be successfully applied. This paper presents an algorithm for the automatic detection of white blood cells embedded into complicated and cluttered smear images that considers the complete process as a circle detection problem. The approach is based on a nature-inspired technique called the electromagnetism-like optimization (EMO) algorithm which is a heuristic method that follows electromagnetism principles for solving complex optimization problems. The proposed approach uses an objective function which measures the resemblance of a candidate circle to an actual WBC. Guided by the values of such objective function, the set of encoded candidate circles are evolved by using EMO, so that they can fit into the actual blood cells contained in the edge map of the image. Experimental results from blood cell images with a varying range of complexity are included to validate the efficiency of the proposed technique regarding detection, robustness, and stability. PMID:23476713

Where will the stem cells lead us? Prospects for dentistry in the 21st century

PubMed Central

Sreenivas, S. Durga; Rao, Akula Sreenivasa; Satyavani, S. Sri; Reddy, Bavigadda Harish; Vasudevan, Sanjay

2011-01-01

It is dentists’ dream to achieve bone repair with predictability, but without donor site morbidity as well as reconstruction of injured or pathologically damaged complex dental structures, however, this will no longer be a dream as these are being made into a reality using stem cell science. Stem cell science is clearly an intriguing and promising area of science. Stem cells have been isolated from a variety of embryonic and adult tissues. Dental stem cells are multipotent mesenchymal stem cells (MSCs) brought new enthusiasm among the researchers because of their easy accessibility, high quality and they don’t pose the same ethical concerns and controversy in comparison with embryonic stem cells. This review article provides brief insights about stem cell basics, the state of art in human dental stem cell research and its possible impact on future dentistry. Even though most of these modalities are still in infancy, it is evident that the 21st century dentist is going to play a critical role in the field of medicine. The aim of this article is to bring awareness among the dentists about the huge potential associated with the use of stem cells in a clinical setting, as well as proper understanding of related problems. PMID:22028504

Clinical translation of bioartificial liver support systems with human pluripotent stem cell-derived hepatic cells

PubMed Central

Sakiyama, Ryoichi; Blau, Brandon J; Miki, Toshio

2017-01-01

There is currently a pressing need for alternative therapies to liver transplantation. The number of patients waiting for a liver transplant is substantially higher than the number of transplantable donor livers, resulting in a long waiting time and a high waiting list mortality. An extracorporeal liver support system is one possible approach to overcome this problem. However, the ideal cell source for developing bioartificial liver (BAL) support systems has yet to be determined. Recent advancements in stem cell technology allow researchers to generate highly functional hepatocyte-like cells from human pluripotent stem cells (hPSCs). In this mini-review, we summarize previous clinical trials with different BAL systems, and discuss advantages of and potential obstacles to utilizing hPSC-derived hepatic cells in clinical-scale BAL systems. PMID:28373763

The Energy Problem: What the Helios Project Can Do About it (LBNL Science at the Theater)

ScienceCinema

Chu, Steven

2018-06-15

The energy problem is one of the most important issues that science and technology has to solve. Nobel laureate and Berkeley Lab Director Steven Chu proposes an aggressive research program to transform the existing and future energy systems of the world away from technologies that emit greenhouse gases. Berkeley Lab's Helios Project concentrates on renewable fuels, such as biofuels, and solar technologies, including a new generation of solar photovoltaic cells and the conversion of electricity into chemical storage to meet future demand.

Learning nucleic acids solving by bioinformatics problems.

PubMed

Nunes, Rhewter; Barbosa de Almeida Júnior, Edivaldo; Pessoa Pinto de Menezes, Ivandilson; Malafaia, Guilherme

2015-01-01

The article describes the development of a new approach to teach molecular biology to undergraduate biology students. The 34 students who participated in this research belonged to the first period of the Biological Sciences teaching course of the Instituto Federal Goiano at Urutaí Campus, Brazil. They were registered in Cell Biology in the first semester of 2013. They received four 55 min-long expository/dialogued lectures that covered the content of "structure and functions of nucleic acids". Later the students were invited to attend four meetings (in a computer laboratory) in which some concepts of Bioinformatics were presented and some problems of the Rosalind platform were solved. The observations we report here are very useful as a broad groundwork to development new research. An interesting possibility is research into the effects of bioinformatics interventions that improve molecular biology learning. © 2015 The International Union of Biochemistry and Molecular Biology.

Biomimicry in biomedical research

PubMed Central

Zhang, Ge

2012-01-01

Biomimicry (literally defined as the imitation of life or nature) has sparked a variety of human innovations and inspired countless cutting-edge designs. From spider silk-made artificial skin to lotus leaf-inspired self-cleaning materials, biomimicry endeavors to solve human problems. Biomimetic approaches have contributed significantly to advances biomedical research during recent years. Using polyacrylamide gels to mimic the elastic modulus of different biological tissues, Disher’s lab has directed meschymal stem cell differentiation into specific lineages.1 They have shown that soft substrates mimicking the elastic modulus of brain tissues (0.1~1 kPa) were neurogenic, substrates of intermediate elastic modulus mimicking muscle (8 ~17 kPa) were myogenic, and substrates with bone-like elastic modulus (25~40 kPa) were osteogenic. This work represents a novel way to regulate the fate of stem cells and exerts profound influence on stem cell research. Biomimcry also drives improvements in tissue engineering. Novel scaffolds have been designed to capture extracellular matrix-like structures, binding of ligands, sustained release of cytokines, and mechanical properties intrinsic to specific tissues for tissue engineering applications.2,3 For example, tissue engineering skin grafts have been designed to mimic the cell composition and layered structure of native skin.4 Similarly, in the field of regenerative medicine, researchers aim to create biomimetic scaffolds to mimic the properties of a native stem cell environment (niche) to dynamically interact with the entrapped stem cells and direct their response.5 PMID:23275257

Henrietta Lacks, HeLa cells, and cell culture contamination.

PubMed

Lucey, Brendan P; Nelson-Rees, Walter A; Hutchins, Grover M

2009-09-01

Henrietta Lacks died in 1951 of an aggressive adenocarcinoma of the cervix. A tissue biopsy obtained for diagnostic evaluation yielded additional tissue for Dr George O. Gey's tissue culture laboratory at Johns Hopkins (Baltimore, Maryland). The cancer cells, now called HeLa cells, grew rapidly in cell culture and became the first human cell line. HeLa cells were used by researchers around the world. However, 20 years after Henrietta Lacks' death, mounting evidence suggested that HeLa cells contaminated and overgrew other cell lines. Cultures, supposedly of tissues such as breast cancer or mouse, proved to be HeLa cells. We describe the history behind the development of HeLa cells, including the first published description of Ms Lacks' autopsy, and the cell culture contamination that resulted. The debate over cell culture contamination began in the 1970s and was not harmonious. Ultimately, the problem was not resolved and it continues today. Finally, we discuss the philosophical implications of the immortal HeLa cell line.

The Holy Grail of Orthopedic Surgery: Mesenchymal Stem Cells—Their Current Uses and Potential Applications

PubMed Central

Berebichez-Fridman, Roberto; Gómez-García, Ricardo; Berebichez-Fastlicht, Enrique; Olivos-Meza, Anell; Granados, Julio; Velasquillo, Cristina

2017-01-01

Only select tissues and organs are able to spontaneously regenerate after disease or trauma, and this regenerative capacity diminishes over time. Human stem cell research explores therapeutic regenerative approaches to treat various conditions. Mesenchymal stem cells (MSCs) are derived from adult stem cells; they are multipotent and exert anti-inflammatory and immunomodulatory effects. They can differentiate into multiple cell types of the mesenchyme, for example, endothelial cells, osteoblasts, chondrocytes, fibroblasts, tenocytes, vascular smooth muscle cells, and sarcomere muscular cells. MSCs are easily obtained and can be cultivated and expanded in vitro; thus, they represent a promising and encouraging treatment approach in orthopedic surgery. Here, we review the application of MSCs to various orthopedic conditions, namely, orthopedic trauma; muscle injury; articular cartilage defects and osteoarthritis; meniscal injuries; bone disease; nerve, tendon, and ligament injuries; spinal cord injuries; intervertebral disc problems; pediatrics; and rotator cuff repair. The use of MSCs in orthopedics may transition the practice in the field from predominately surgical replacement and reconstruction to bioregeneration and prevention. However, additional research is necessary to explore the safety and effectiveness of MSC treatment in orthopedics, as well as applications in other medical specialties. PMID:28698718

Human embryonic stem cell lines: socio-legal concerns and therapeutic promise.

PubMed

McLaren, Anne

2002-10-01

Stem cell lines would be very valuable for the repair of diseased or damaged organs. Stem cells derived from adult tissues raise few ethical problems, and would not be rejected if derived from the patient. They show considerable plasticity and might be appropriate for some clinical conditions, but they tend not to grow well in culture. Stem cells derived from the early human embryo proliferate indefinitely in culture and can give rise to many different tissues, but their derivation requires destruction of the embryo, which is not ethically acceptable in some countries. Other countries allow strictly regulated destructive research on human embryos, usually those that have been produced for infertile couples in infertility clinics. Embryos that are no longer required for the couple's own reproductive project could be donated for research rather than just discarded. Different approaches are being developed to avoid immunological rejection of embryonic stem cells used for therapy. Derivation of embryonic stem cell lines by somatic cell nuclear transfer ('cloning') from the patients themselves might be one possible approach, but is unlikely to be used in routine clinical practice if more cost-effective methods are available.

Desired Precision in Multi-Objective Optimization: Epsilon Archiving or Rounding Objectives?

NASA Astrophysics Data System (ADS)

Asadzadeh, M.; Sahraei, S.

2016-12-01

Multi-objective optimization (MO) aids in supporting the decision making process in water resources engineering and design problems. One of the main goals of solving a MO problem is to archive a set of solutions that is well-distributed across a wide range of all the design objectives. Modern MO algorithms use the epsilon dominance concept to define a mesh with pre-defined grid-cell size (often called epsilon) in the objective space and archive at most one solution at each grid-cell. Epsilon can be set to the desired precision level of each objective function to make sure that the difference between each pair of archived solutions is meaningful. This epsilon archiving process is computationally expensive in problems that have quick-to-evaluate objective functions. This research explores the applicability of a similar but computationally more efficient approach to respect the desired precision level of all objectives in the solution archiving process. In this alternative approach each objective function is rounded to the desired precision level before comparing any new solution to the set of archived solutions that already have rounded objective function values. This alternative solution archiving approach is compared to the epsilon archiving approach in terms of efficiency and quality of archived solutions for solving mathematical test problems and hydrologic model calibration problems.

Blood-brain barrier and foetal-onset hydrocephalus, with a view on potential novel treatments beyond managing CSF flow.

PubMed

Guerra, M; Blázquez, J L; Rodríguez, E M

2017-07-13

Despite decades of research, no compelling non-surgical therapies have been developed for foetal hydrocephalus. So far, most efforts have pointed to repairing disturbances in the cerebrospinal fluid (CSF) flow and to avoid further brain damage. There are no reports trying to prevent or diminish abnormalities in brain development which are inseparably associated with hydrocephalus. A key problem in the treatment of hydrocephalus is the blood-brain barrier that restricts the access to the brain for therapeutic compounds or systemically grafted cells. Recent investigations have started to open an avenue for the development of a cell therapy for foetal-onset hydrocephalus. Potential cells to be used for brain grafting include: (1) pluripotential neural stem cells; (2) mesenchymal stem cells; (3) genetically-engineered stem cells; (4) choroid plexus cells and (5) subcommissural organ cells. Expected outcomes are a proper microenvironment for the embryonic neurogenic niche and, consequent normal brain development.

Governing stem cell therapy in India: regulatory vacuum or jurisdictional ambiguity?

PubMed Central

Tiwari, Shashank S.; Raman, Sujatha

2014-01-01

Stem cell treatments are being offered in Indian clinics although preclinical evidence of their efficacy and safety is lacking. This is attributed to a governance vacuum created by the lack of legally binding research guidelines. By contrast, this paper highlights jurisdictional ambiguities arising from trying to regulate stem cell therapy under the auspices of research guidelines when treatments are offered in a private market disconnected from clinical trials. While statutory laws have been strengthened in 2014, prospects for their implementation remain weak, given embedded challenges of putting healthcare laws and professional codes into practice. Finally, attending to the capacities of consumer law and civil society activism to remedy the problem of unregulated treatments, the paper finds that the very definition of a governance vacuum needs to be reframed to clarify whose rights to health care are threatened by the proliferation of commercial treatments and individualized negligence-based remedies for grievances. PMID:25431534

Nuclear transfer to study the nuclear reprogramming of human stem cells.

PubMed

Saito, Shigeo; Sawai, Ken; Murayama, Yoshinobu; Fukuda, Keiichi; Yokoyama, Kazunari

2008-01-01

Research of stem cells will enable us to understand the development and function of tissues and organs in mammals. The ability to induce regeneration of new tissues from embryonic stem (ES) cells derived from cloned blastocysts via nuclear transfer can be expected in the not-too-distant future. The fact that there is no way except nuclear cloning for the return of differentiated cells to undifferentiated cells remains an interesting problem to be solved. We describe protocols for the production of cloned calves from bovine ES cells to study nuclear reprogramming ability of stem cells. The frequency of term pregnancies for blastocysts from ES cells is higher than those of early pregnancies and maintained pregnancies after nuclear transfer with bovine somatic cells. We also describe protocols for gene introduction into bovine ES cells in vitro, particularly the human leukocyte antigens (HLA). Bovine ES cells provide a powerful tool for the generation of transgenic clonal offspring. This technique, when perfected for humans, may be critical for neural stem cell transplantation.

Nickel-hydrogen separator development

NASA Technical Reports Server (NTRS)

Gonzalez-Sanabria, O. D.

1986-01-01

The separator technology is a critical element in the nickel-hydrogen (Ni-H2) systems. Previous research and development work carried out at NASA Lewis Research Center has determined that separators made from zirconium oxide (ZrO2) and potassium titanate (PKT) fibers will function satisfactorily in Ni-H2 cells without exhibiting the problems associated with the asbestos separators. A program has been established to transfer the separator technology into a commercial production line. A detailed plan of this program will be presented and the preliminary results will be discussed.

Biomedical research

NASA Technical Reports Server (NTRS)

1981-01-01

Biomedical problems encountered by man in space which have been identified as a result of previous experience in simulated or actual spaceflight include cardiovascular deconditioning, motion sickness, bone loss, muscle atrophy, red cell alterations, fluid and electrolyte loss, radiation effects, radiation protection, behavior, and performance. The investigations and the findings in each of these areas were reviewed. A description of how biomedical research is organized within NASA, how it is funded, and how it is being reoriented to meet the needs of future manned space missions is also provided.

Biodegradable Polymers and Stem Cells for Bioprinting.

PubMed

Lei, Meijuan; Wang, Xiaohong

2016-04-29

It is imperative to develop organ manufacturing technologies based on the high organ failure mortality and serious donor shortage problems. As an emerging and promising technology, bioprinting has attracted more and more attention with its super precision, easy reproduction, fast manipulation and advantages in many hot research areas, such as tissue engineering, organ manufacturing, and drug screening. Basically, bioprinting technology consists of inkjet bioprinting, laser-based bioprinting and extrusion-based bioprinting techniques. Biodegradable polymers and stem cells are common printing inks. In the printed constructs, biodegradable polymers are usually used as support scaffolds, while stem cells can be engaged to differentiate into different cell/tissue types. The integration of biodegradable polymers and stem cells with the bioprinting techniques has provided huge opportunities for modern science and technologies, including tissue repair, organ transplantation and energy metabolism.

Differential Effects of Tissue Culture Coating Substrates on Prostate Cancer Cell Adherence, Morphology and Behavior

PubMed Central

Liberio, Michelle S.; Sadowski, Martin C.; Soekmadji, Carolina; Davis, Rohan A.; Nelson, Colleen C.

2014-01-01

Weak cell-surface adhesion of cell lines to tissue culture surfaces is a common problem and presents technical limitations to the design of experiments. To overcome this problem, various surface coating protocols have been developed. However, a comparative and precise real-time measurement of their impact on cell behavior has not been conducted. The prostate cancer cell line LNCaP, derived from a patient lymph node metastasis, is a commonly used model system in prostate cancer research. However, the cells’ characteristically weak attachment to the surface of tissue culture vessels and cover slips has impeded their manipulation and analysis and use in high throughput screening. To improve the adherence of LNCaP cells to the culture surface, we compared different coating reagents (poly-l-lysine, poly-l-ornithine, collagen type IV, fibronectin, and laminin) and culturing conditions and analyzed their impact on cell proliferation, adhesion, morphology, mobility and gene expression using real-time technologies. The results showed that fibronectin, poly-l-lysine and poly-l-ornithine improved LNCaP cells adherence and provoked cell morphology alterations, such as increase of nuclear and cellular area. These coating reagents also induced a higher expression of F-actin and reduced cell mobility. In contrast, laminin and collagen type IV did not improve adherence but promoted cell aggregation and affected cell morphology. Cells cultured in the presence of laminin displayed higher mobility than control cells. All the coating conditions significantly affected cell viability; however, they did not affect the expression of androgen receptor-regulated genes. Our comparative findings provide important insight for the selection of the ideal coating reagent and culture conditions for the cancer cell lines with respect to their effect on proliferation rate, attachment, morphology, migration, transcriptional response and cellular cytoskeleton arrangement. PMID:25375165

Cell-based delivery of oncolytic viruses: a new strategic alliance for a biological strike against cancer.

PubMed

Power, Anthony T; Bell, John C

2007-04-01

Recent years have seen tremendous advances in the development of exquisitely targeted replicating virotherapeutics that can safely destroy malignant cells. Despite this promise, clinical advancement of this powerful and unique approach has been hindered by vulnerability to host defenses and inefficient systemic delivery. However, it now appears that delivery of oncolytic viruses within carrier cells may offer one solution to this critical problem. In this review, we compare the advantages and limitations of the numerous cell lineages that have been investigated as delivery platforms for viral therapeutics, and discuss examples showing how combined cell-virus biotherapeutics can be used to achieve synergistic gains in antitumor activity. Finally, we highlight avenues for future preclinical research that might be taken in order to refine cell-virus biotherapeutics in preparation for human trials.

Lithium cell tests at Langley Research Center. [for the long duration exposure facility

NASA Technical Reports Server (NTRS)

Bene, J.

1977-01-01

The long duration exposure facility mission places temperature requirements of from -30 F to +150 F on the batteries to be used. A hermetically sealed lithium sulfur dioxide cell was tested to predict what the temperature of the battery would be over a given spectrum of temperatures of operation. Near the end of cell discharge, as the voltage started collapsing, a very high heat output rise due to chemical reaction took place. However, if the cells were thermally insulated, they vented, ignited, and burned if an attempt was made to discharge them all the way. The cells do not go into reversal. It was determined that the root of the problem was probably the chemical reaction between the lithium and the acetonitrite solvent. A redesigned cell is discussed as well as some alternates.

The Problem of Scale in the Interpretation of Pictorial Representations of Cell Structure

ERIC Educational Resources Information Center

Vlaardingerbroek, Barend; Taylor, Neil; Bale, Colin

2014-01-01

Diagrams feature prominently in science education, and there has been an increase in research focusing on students' use of them in knowledge construction. This paper reports on an investigation into first year university students' perceptions of scale and size at the cellular level. It was found that many students appeared to tacitly assume that…

Solar Cell Fabrication Studies Pertinent to Developing Countries.

NASA Astrophysics Data System (ADS)

Prah, Joseph Henry

That there is a need in the world today, and in the Third World in particular, for developing renewable energy sources is a proposition without question. Toward that end, the harnessing of solar energy has attracted much attention recently. In this thesis, we have addressed the question of Photovoltaics among the many approaches to the problem as being of poignant relevance in the Third World. Based on our studies, which involved the physics of solar cells, various solar cell configurations, the materials for their fabrication and their fabrication sequences, we arrived at the conclusion that silicon homojunction solar cells are best suited to the present needs and environment of, and suitable for development in the Third World, though Cadmium Sulphide-Cuprous Sulphide solar cell could be considered as a viable future candidate. Attendant with the adoption of photovoltaics as electric energy supply, is the problem of technology transfer and development. Towards that goal, we carried out in the laboratory, the fabrication of solar cells using very simple fabrication sequences and materials to demonstrate that tolerable efficiencies are achievable by their use. The view is also presented that for a thriving and viable solar cell industry in the Third World, the sine qua non is an integrated national policies involving all facets of solar cell manufacture and application, namely, material processing and fabrication, basic research, and development and socio -economic acceptance of solar cell appliances. To demonstrate how basic research could benefit solar cell fabrication, we undertook a number of experiments, such as varying our fabrication sequences and materials, finding their radiation tolerance, and carrying out Deep Level Transient Spectroscopy (DLTS) studies, in an attempt to understand some of the fabrication and environmental factors which limit solar cell performance. We thus found that subjecting wafers to preheat treatments does not improve solar cell performance, but rather reduces solar cell radiation tolerance. Also P-type substrate solar cells were found to be more radiation resistant than N-type substrate solar cells. The Deep Level Transient Spectroscopy results showed that carbon and oxygen, as one would expect, are chief contaminants of the silicon wafers that we used in the fabrication of our solar cells. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI.

SINGLE MOLECULE APPROACHES TO BIOLOGY, 2010 GORDON RESEARCH CONFERENCE, JUNE 27-JULY 2, 2010, ITALY

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

Professor William Moerner

2010-07-09

The 2010 Gordon Conference on Single-Molecule Approaches to Biology focuses on cutting-edge research in single-molecule science. Tremendous technical developments have made it possible to detect, identify, track, and manipulate single biomolecules in an ambient environment or even in a live cell. Single-molecule approaches have changed the way many biological problems are addressed, and new knowledge derived from these approaches continues to emerge. The ability of single-molecule approaches to avoid ensemble averaging and to capture transient intermediates and heterogeneous behavior renders them particularly powerful in elucidating mechanisms of biomolecular machines: what they do, how they work individually, how they work together,more » and finally, how they work inside live cells. The burgeoning use of single-molecule methods to elucidate biological problems is a highly multidisciplinary pursuit, involving both force- and fluorescence-based methods, the most up-to-date advances in microscopy, innovative biological and chemical approaches, and nanotechnology tools. This conference seeks to bring together top experts in molecular and cell biology with innovators in the measurement and manipulation of single molecules, and will provide opportunities for junior scientists and graduate students to present their work in poster format and to exchange ideas with leaders in the field. A number of excellent poster presenters will be selected for short oral talks. Topics as diverse as single-molecule sequencing, DNA/RNA/protein interactions, folding machines, cellular biophysics, synthetic biology and bioengineering, force spectroscopy, new method developments, superresolution imaging in cells, and novel probes for single-molecule imaging will be on the program. Additionally, the collegial atmosphere of this Conference, with programmed discussion sessions as well as opportunities for informal gatherings in the afternoons and evenings in the beauty of the Il Ciocco site in Tuscany, provides an avenue for scientists from different disciplines to interact and brainstorm and promotes cross-disciplinary collaborations directed toward compelling biological problems.« less

Inverters for interfacing of solar cells with the power grid

NASA Astrophysics Data System (ADS)

Karamanzanis, G. N.; Jackson, R. D.

In this work, based on a research course in the Engineering Dep. Cambridge University, some non-classical inverter circuits are studied. They can be used for interfacing solar cells with the power grid at low voltage (230V) and at low power level. They are based on d.c. choppers which have a fast switching transistor. Their theoretical efficiency is 100 percent and they provide a satisfactory output current waveform in phase to the a.c. line voltage. The problems of control are also studied using a suitable mathematical model.

Single-cell sequencing technologies: current and future.

PubMed

Liang, Jialong; Cai, Wanshi; Sun, Zhongsheng

2014-10-20

Intensively developed in the last few years, single-cell sequencing technologies now present numerous advantages over traditional sequencing methods for solving the problems of biological heterogeneity and low quantities of available biological materials. The application of single-cell sequencing technologies has profoundly changed our understanding of a series of biological phenomena, including gene transcription, embryo development, and carcinogenesis. However, before single-cell sequencing technologies can be used extensively, researchers face the serious challenge of overcoming inherent issues of high amplification bias, low accuracy and reproducibility. Here, we simply summarize the techniques used for single-cell isolation, and review the current technologies used in single-cell genomic, transcriptomic, and epigenomic sequencing. We discuss the merits, defects, and scope of application of single-cell sequencing technologies and then speculate on the direction of future developments. Copyright © 2014 Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, and Genetics Society of China. Published by Elsevier Ltd. All rights reserved.

New technologies for the human cytome project.

PubMed

Tárnok, A

2004-01-01

Cytomes or cell systems are composed of various kinds of single-cells and constitute the elementary building units of organs and organisms. Their individualised (cytomic) analysis overcomes the problem of averaged results from cell and tissue homogenates where molecular changes in low frequency cell populations may be hidden and wrongly interpreted. Analysis of the cytome is of pivotal importance in basic research for the understanding of cells and their interrelations in complex environments like tissues and in predictive medicine where it is a prerequisite for individualised preventive therapy. Analysis of molecular phenotypes requires instrumentation that on the one hand provides high-throughput measurement of individual cells and is on the other hand highly multiplexed, enabling the simultaneous acquisition of many parameters on the single cell level. Upcoming technology suitable to this task, such as slide based cytometry is available or under development. The realisation of cytomic technology is important for the realisation of the human cytome project.

Contested embryonic culture in Japan--public discussion, and human embryonic stem cell research in an aging welfare society.

PubMed

Sleeboom-Faulkner, Margaret

2010-01-01

This article explores the reasons for the lack of a broad discussion on bioethical regulation of human embryonic stem cell research (hESR) in Japan and asks why scientists experience difficulties accessing resources for hESR despite the acclaimed indifference of dominant Japanese culture to embryo research. The article shows how various social actors express their views on the embryo and oocyte donation in terms of dominant Japanese culture, foiled against what is regarded as Western culture. Second, it shows how the lack of concern with hESR should be understood in the context of public health policies and communications and bioethics decision making in Japan. Finally, it interprets the meaning of the embryo in the context of Japan as an aging modern welfare society, explaining how policymakers have come to emphasize the urgency of infertility problems over issues around abortion and embryonic life.

[Fine structure of glial cells in the central nervous system of the tapeworm Grillotia erinaceus (Cestoda: Trypanorhyncha)].

PubMed

Biserova, N M

2008-01-01

The problem of glial cells existing in parasitic and free living flatworms is correlated with organization of parenchyma in platyhelmintes. In the contrary to the widespread opinion that myelin-like envelopes and glial cells do not exist in the nervous system of parasitic flatworms, it has been shown by ultrastructural researches that Amphilina foliacea (Cestoda, Amphilinidea) has well developed glial cells and myelin-like envelopes in the ganglia and main cords, which include both glial cells and intercellular components. The aim of our research was to reveal and investigate in details structural components corresponding to the concept of the glial cell in the CNS of Grillotia erinaceus (Cestoda: Trypanorhyncha). Three types of glial cells have been found. The first type is the fibroblast-like glial cells; cells locate in the cerebral ganglion, contain in cytoplasm and extract out fibrillar matrix, form desmosomes and have supporting function. The glial cells of the second type form myeline-like envelope of the giant axons and bulbar nerves in scolex and have laminar cytoplasm. These cells are numerous and exceed in number the neurons bodies into the nerve. The glial cells of the third type form multilayer envelopes in the main nerve cords; extra cellular fibers and gap-junctions take place between the layers. There are contacts between the glial cells of the third type and excretory epithelium but specialized contacts with neurons have been not found. The existing of glial cells in free living and parasitic flatworms is discussed.

Stem cell sources for clinical islet transplantation in type 1 diabetes: embryonic and adult stem cells.

PubMed

Miszta-Lane, Helena; Mirbolooki, Mohammadreza; James Shapiro, A M; Lakey, Jonathan R T

2006-01-01

Lifelong immunosuppressive therapy and inadequate sources of transplantable islets have led the islet transplantation benefits to less than 0.5% of type 1 diabetics. Whereas the potential risk of infection by animal endogenous viruses limits the uses of islet xeno-transplantation, deriving islets from stem cells seems to be able to overcome the current problems of islet shortages and immune compatibility. Both embryonic (derived from the inner cell mass of blastocysts) and adult stem cells (derived from adult tissues) have shown controversial results in secreting insulin in vitro and normalizing hyperglycemia in vivo. ESCs research is thought to have much greater developmental potential than adult stem cells; however it is still in the basic research phase. Existing ESC lines are not believed to be identical or ideal for generating islets or beta-cells and additional ESC lines have to be established. Research with ESCs derived from humans is controversial because it requires the destruction of a human embryo and/or therapeutic cloning, which some believe is a slippery slope to reproductive cloning. On the other hand, adult stem cells are already in some degree specialized, recipients may receive their own stem cells. They are flexible but they have shown mixed degree of availability. Adult stem cells are not pluripotent. They may not exist for all organs. They are difficult to purify and they cannot be maintained well outside the body. In order to draw the future avenues in this field, existent discrepancies between the results need to be clarified. In this study, we will review the different aspects and challenges of using embryonic or adult stem cells in clinical islet transplantation for the treatment of type 1 diabetes.

Safety considerations of lithium-thionyl chloride cells

NASA Astrophysics Data System (ADS)

Subbarao, Surampudi; Halpert, Gerald; Stein, Irving

1986-06-01

The use of spirally wound lithium-thionyl chloride (Li-SOCl2) cells is currently limited because of their hazardous behavior. Safety hazards have ranged from mild venting of toxic materials to violent explosions and fires. These incidents may be related to both user- and manufacturer-induced causes. Many explanations have been offered to explain the unsafe behavior of the cells under operating and abuse conditions. Explanations fall into two categories: (1) thermal mechanisms, and (2) chemical mechanisms. However, it is quite difficult to separate the two. Both may be responsible for cell venting or explosion. Some safety problems encountered with these cells also may be due to design deficiencies and ineffective quality control during cell fabrication. A well-coordinated basic and applied research program is needed to develop safe Li-SOCl2 cells. Recommendations include: (1) learnig more about Li-SOL2 cell chemistry; (2) modeling cell and battery behavior; (3) optimizing cell design for safety and performance, (4) implementing quality control procedures; and (5) educating users.

Safety considerations of lithium-thionyl chloride cells

NASA Technical Reports Server (NTRS)

Subbarao, Surampudi; Halpert, Gerald; Stein, Irving

1986-01-01

The use of spirally wound lithium-thionyl chloride (Li-SOCl2) cells is currently limited because of their hazardous behavior. Safety hazards have ranged from mild venting of toxic materials to violent explosions and fires. These incidents may be related to both user- and manufacturer-induced causes. Many explanations have been offered to explain the unsafe behavior of the cells under operating and abuse conditions. Explanations fall into two categories: (1) thermal mechanisms, and (2) chemical mechanisms. However, it is quite difficult to separate the two. Both may be responsible for cell venting or explosion. Some safety problems encountered with these cells also may be due to design deficiencies and ineffective quality control during cell fabrication. A well-coordinated basic and applied research program is needed to develop safe Li-SOCl2 cells. Recommendations include: (1) learnig more about Li-SOL2 cell chemistry; (2) modeling cell and battery behavior; (3) optimizing cell design for safety and performance, (4) implementing quality control procedures; and (5) educating users.

Research on treatment of wastewater containing heavy metal by microbial fuel cell

NASA Astrophysics Data System (ADS)

Chen, Zixuan; Lu, Xun; Yin, Ruixia; Luo, Yunyi; Mai, Hanjian; Zhang, Nan; Xiong, Jingfang; Zhang, Hongguo; Tang, Jinfeng; Luo, Dinggui

2018-02-01

With rapid development of social economy, serious problem has been caused by wastewater containing heavy metals, which was difficult to be treated by many kinds of traditional treatment methods, such as complex processes, high cost or easy to cause secondary pollution. As a novel biological treatment technology, microbial fuel cells (MFC) can generate electric energy while dealing with wastewater, which was proposed and extensively studied. This paper introduced the working principle of MFC, the classification of cathode, and the research progress on the treatment of wastewater containing Cr(VI), Cu(II), Ag(I), Mn(II) and Cd(II) by MFC. The study found that different cathode, different heavy metals anddifferent hybrid systems would affect the performance of the system and removal effect for heavy metal in MFC. MFC was a highly potential pollution control technology. Until now, the research was still in the laboratory stage. Its industrial application for recovery of heavy metal ion, improving the energy recovery rate and improvement or innovation of system were worthy of further research.

Steam electrolysis by solid oxide electrolysis cells (SOECs) with proton-conducting oxides.

PubMed

Bi, Lei; Boulfrad, Samir; Traversa, Enrico

2014-12-21

Energy crisis and environmental problems caused by the conventional combustion of fossil fuels boost the development of renewable and sustainable energies. H2 is regarded as a clean fuel for many applications and it also serves as an energy carrier for many renewable energy sources, such as solar and wind power. Among all the technologies for H2 production, steam electrolysis by solid oxide electrolysis cells (SOECs) has attracted much attention due to its high efficiency and low environmental impact, provided that the needed electrical power is generated from renewable sources. However, the deployment of SOECs based on conventional oxygen-ion conductors is limited by several issues, such as high operating temperature, hydrogen purification from water, and electrode stability. To avoid these problems, proton-conducting oxides are proposed as electrolyte materials for SOECs. This review paper provides a broad overview of the research progresses made for proton-conducting SOECs, summarizing the past work and finding the problems for the development of proton-conducting SOECs, as well as pointing out potential development directions.

Maternal cell phone use during pregnancy and child behavioral problems in five birth cohorts.

PubMed

Birks, Laura; Guxens, Mònica; Papadopoulou, Eleni; Alexander, Jan; Ballester, Ferran; Estarlich, Marisa; Gallastegi, Mara; Ha, Mina; Haugen, Margaretha; Huss, Anke; Kheifets, Leeka; Lim, Hyungryul; Olsen, Jørn; Santa-Marina, Loreto; Sudan, Madhuri; Vermeulen, Roel; Vrijkotte, Tanja; Cardis, Elisabeth; Vrijheid, Martine

2017-07-01

Previous studies have reported associations between prenatal cell phone use and child behavioral problems, but findings have been inconsistent and based on retrospective assessment of cell phone use. This study aimed to assess this association in a multi-national analysis, using data from three cohorts with prospective data on prenatal cell phone use, together with previously published data from two cohorts with retrospectively collected cell phone use data. We used individual participant data from 83,884 mother-child pairs in the five cohorts from Denmark (1996-2002), Korea (2006-2011), the Netherlands (2003-2004), Norway (2004-2008), and Spain (2003-2008). We categorized cell phone use into none, low, medium, and high, based on frequency of calls during pregnancy reported by the mothers. Child behavioral problems (reported by mothers using the Strengths and Difficulties Questionnaire or Child Behavior Checklist) were classified in the borderline/clinical and clinical ranges using validated cut-offs in children aged 5-7years. Cohort specific risk estimates were meta-analyzed. Overall, 38.8% of mothers, mostly from the Danish cohort, reported no cell phone use during pregnancy and these mothers were less likely to have a child with overall behavioral, hyperactivity/inattention or emotional problems. Evidence for a trend of increasing risk of child behavioral problems through the maternal cell phone use categories was observed for hyperactivity/inattention problems (OR for problems in the clinical range: 1.11, 95%CI 1.01, 1.22; 1.28, 95%CI 1.12, 1.48, among children of medium and high users, respectively). This association was fairly consistent across cohorts and between cohorts with retrospectively and prospectively collected cell phone use data. Maternal cell phone use during pregnancy may be associated with an increased risk for behavioral problems, particularly hyperactivity/inattention problems, in the offspring. The interpretation of these results is unclear as uncontrolled confounding may influence both maternal cell phone use and child behavioral problems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Asymmetric cell division requires specific mechanisms for adjusting global transcription.

PubMed

Mena, Adriana; Medina, Daniel A; García-Martínez, José; Begley, Victoria; Singh, Abhyudai; Chávez, Sebastián; Muñoz-Centeno, Mari C; Pérez-Ortín, José E

2017-12-01

Most cells divide symmetrically into two approximately identical cells. There are many examples, however, of asymmetric cell division that can generate sibling cell size differences. Whereas physical asymmetric division mechanisms and cell fate consequences have been investigated, the specific problem caused by asymmetric division at the transcription level has not yet been addressed. In symmetrically dividing cells the nascent transcription rate increases in parallel to cell volume to compensate it by keeping the actual mRNA synthesis rate constant. This cannot apply to the yeast Saccharomyces cerevisiae, where this mechanism would provoke a never-ending increasing mRNA synthesis rate in smaller daughter cells. We show here that, contrarily to other eukaryotes with symmetric division, budding yeast keeps the nascent transcription rates of its RNA polymerases constant and increases mRNA stability. This control on RNA pol II-dependent transcription rate is obtained by controlling the cellular concentration of this enzyme. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Keeping in touch. Cell phone use in people with schizophrenia disorders.

PubMed

Beebe, Lora Humphrey; Smith, Kathlene; Bennett, Chris; Bentley, Katherine; Walters, Amanda B; Hancock, Beverly; Farmer, Shirley Y; Earle, Karen; White, Sheila

2010-04-01

There is limited research exploring telephone intervention for psychiatric clients; no studies specific to cell phone use have been conducted. This pilot study examined the feasibility and acceptability of cell phone use in individuals with schizophrenia spectrum disorders (SSDs). Ten outpatients with SSDs were provided with previously activated cell phones for 5 months; trained nurses contacted participants weekly. Seven participants completed the 5-month follow-up period. A minority of participants reported difficulty retrieving messages and answering or charging their phone. These preliminary findings indicate the majority of individuals with SSDs are willing to use this method of communication and are able to do so with few problems. Possible barriers to the use of cell phones with this group include lifestyle factors and poor decision making. Future investigations should examine the use of cell phone access to foster personal safety, gain a sense of connectedness to others, and enhance quality of life.

A Checklist for Successful Quantitative Live Cell Imaging in Systems Biology

PubMed Central

Sung, Myong-Hee

2013-01-01

Mathematical modeling of signaling and gene regulatory networks has provided unique insights about systems behaviors for many cell biological problems of medical importance. Quantitative single cell monitoring has a crucial role in advancing systems modeling of molecular networks. However, due to the multidisciplinary techniques that are necessary for adaptation of such systems biology approaches, dissemination to a wide research community has been relatively slow. In this essay, I focus on some technical aspects that are often under-appreciated, yet critical in harnessing live cell imaging methods to achieve single-cell-level understanding and quantitative modeling of molecular networks. The importance of these technical considerations will be elaborated with examples of successes and shortcomings. Future efforts will benefit by avoiding some pitfalls and by utilizing the lessons collectively learned from recent applications of imaging in systems biology. PMID:24709701

The ghosts of HeLa: How cell line misidentification contaminates the scientific literature

PubMed Central

2017-01-01

While problems with cell line misidentification have been known for decades, an unknown number of published papers remains in circulation reporting on the wrong cells without warning or correction. Here we attempt to make a conservative estimate of this ‘contaminated’ literature. We found 32,755 articles reporting on research with misidentified cells, in turn cited by an estimated half a million other papers. The contamination of the literature is not decreasing over time and is anything but restricted to countries in the periphery of global science. The decades-old and often contentious attempts to stop misidentification of cell lines have proven to be insufficient. The contamination of the literature calls for a fair and reasonable notification system, warning users and readers to interpret these papers with appropriate care. PMID:29023500

Rouleaux red blood cells splitting in microscopic thin blood smear images via local maxima, circles drawing, and mapping with original RBCs.

PubMed

Rehman, Amjad; Abbas, Naveed; Saba, Tanzila; Mahmood, Toqeer; Kolivand, Hoshang

2018-04-10

Splitting the rouleaux RBCs from single RBCs and its further subdivision is a challenging area in computer-assisted diagnosis of blood. This phenomenon is applied in complete blood count, anemia, leukemia, and malaria tests. Several automated techniques are reported in the state of art for this task but face either under or over splitting problems. The current research presents a novel approach to split Rouleaux red blood cells (chains of RBCs) precisely, which are frequently observed in the thin blood smear images. Accordingly, this research address the rouleaux splitting problem in a realistic, efficient and automated way by considering the distance transform and local maxima of the rouleaux RBCs. Rouleaux RBCs are splitted by taking their local maxima as the centres to draw circles by mid-point circle algorithm. The resulting circles are further mapped with single RBC in Rouleaux to preserve its original shape. The results of the proposed approach on standard data set are presented and analyzed statistically by achieving an average recall of 0.059, an average precision of 0.067 and F-measure 0.063 are achieved through ground truth with visual inspection. © 2018 Wiley Periodicals, Inc.

Use of bioreactors in maxillofacial tissue engineering.

PubMed

Depprich, Rita; Handschel, Jörg; Wiesmann, Hans-Peter; Jäsche-Meyer, Janine; Meyer, Ulrich

2008-07-01

Engineering of various oral tissues is a challenging issue in contemporary maxillofacial reconstructive research. In contrast to the classic biomaterial approach, tissue engineering is based on the understanding of cell driven tissue formation, and aims to generate new functional tissues, rather than just to implant non-living space holders. Researchers hope to reach this goal by combining knowledge from biology, physics, materials science, engineering, and medicine in an integrated manner. Several major technical advances have been made in this field during the last decade, and clinical application is at the stage of first clinical trials. A recent limitation of extracorporally engineered cellular substitutes is the problem of growing enlarged tissues ex vivo. One of the main research topics is therefore to scale up artificial tissue constructs for use in extended defect situations. To overcome the monolayer inherent two-dimensional cell assembly, efforts have been made to grow cells in a three-dimensional space. Bioreactors have therefore been in focus for a considerable time to build up enlarged tissues. The shift from the ex vivo approach of cell multiplication to the generation of a real tissue growth is mirrored by the development of bioreactors, enabling scientists to grow more complex tissue constructs. This present review intends to provide an overview of the current state of art in maxillofacial tissue engineering by the use of bioreactors, its limitations and hopes, as well as the future research trends.

Active radar guides missile to its target: receptor-based targeted treatment of hepatocellular carcinoma by nanoparticulate systems.

PubMed

Yan, Jing-Jun; Liao, Jia-Zhi; Lin, Ju-Sheng; He, Xing-Xing

2015-01-01

Patients with hepatocellular carcinoma (HCC) usually present at advanced stages and do not benefit from surgical resection, so drug therapy should deserve a prominent place in unresectable HCC treatment. But chemotherapy agents, such as doxorubicin, cisplatin, and paclitaxel, frequently encounter important problems such as low specificity and non-selective biodistribution. Recently, the development of nanotechnology led to significant breakthroughs to overcome these problems. Decorating the surfaces of nanoparticulate-based drug carriers with homing devices has demonstrated its potential in concentrating chemotherapy agents specifically to HCC cells. In this paper, we reviewed the current status of active targeting strategies for nanoparticulate systems based on various receptors such as asialoglycoprotein receptor, transferrin receptor, epidermal growth factor receptor, folate receptor, integrin, and CD44, which are abundantly expressed on the surfaces of hepatocytes or liver cancer cells. Furthermore, we pointed out their merits and defects and provided theoretical references for further research.

Ethical aspects of aging research.

PubMed

Seppet, Enn; Pääsuke, Mati; Conte, Maria; Capri, Miriam; Franceschi, Claudio

2011-12-01

During the last 50-60 years, due to development of medical care and hygienically safe living conditions, the average life span of European citizens has substantially increased, with a rapid growth of the population older than 65 years. This trend places ever-growing medical and economical burden on society, as many of the older subjects suffer from age-related diseases and frailty. Coping with these problems requires not only appropriate medical treatment and social support but also extensive research in many fields of aging-from biology to sociology, with involvement of older people as the research subjects. This work anticipates development and application of ethical standards suited to dynamic advances in aging research. The aim of this review is to update the knowledge in ethical requirements toward recruitment of older research subjects, obtaining of informed consent, collection of biological samples, and use of stem cells in preclinical and clinical settings. It is concluded that application of adequate ethical platform markedly facilitates recruitment of older persons for participation in research. Currently, the basic ethical concepts are subjected to extensive discussion, with participation of all interested parties, in order to guarantee successful research on problems of human aging, protect older people from undesired interference, and afford their benefits through supporting innovations in research, therapy, and care.

A New, Dynamic Era for Somatic Cell Nuclear Transfer?

PubMed

Loi, Pasqualino; Iuso, Domenico; Czernik, Marta; Ogura, Atsuo

2016-10-01

Cloning animals by somatic cell nuclear transfer (SCNT) has remained an uncontrollable process for many years. High rates of embryonic losses, stillbirths, and postnatal mortality have been typical outcomes. These developmental problems arise from abnormal genomic reprogramming: the capacity of the oocyte to reset the differentiated memory of a somatic cell. However, effective reprogramming strategies are now available. These target the whole genome or single domains such as the Xist gene, and their effectiveness has been validated with the ability of experimental animals to develop to term. Thus, SCNT has become a controllable process that can be used to 'rescue' endangered species, and for biomedical research such as therapeutic cloning and the isolation of induced pluripotent stem cells (iPSCs). Copyright © 2016 Elsevier Ltd. All rights reserved.

Nickel-hydrogen separator development

NASA Technical Reports Server (NTRS)

Gonzalez-Sanabria, O. D.

1986-01-01

The separator technology is a critical element in the nickel-hydrogen (Ni-H2) systems. Previous research and development work carried out at NASA Lewis Research Center has determined that separators made from zirconium oxide (ZrO2) and potassium titanate (PKT) fibers will function satisfactorily in Ni-H2 cells without exhibiting the problems associated with the asbestos separators. These separators and their characteristics were previously discussed. A program was established to transfer the separator technology into a commercial production line. A detailed plan of this program will be presented and the preliminary results will be discussed.

Multicell migration tracking within angiogenic networks by deep learning-based segmentation and augmented Bayesian filtering.

PubMed

Wang, Mengmeng; Ong, Lee-Ling Sharon; Dauwels, Justin; Asada, H Harry

2018-04-01

Cell migration is a key feature for living organisms. Image analysis tools are useful in studying cell migration in three-dimensional (3-D) in vitro environments. We consider angiogenic vessels formed in 3-D microfluidic devices (MFDs) and develop an image analysis system to extract cell behaviors from experimental phase-contrast microscopy image sequences. The proposed system initializes tracks with the end-point confocal nuclei coordinates. We apply convolutional neural networks to detect cell candidates and combine backward Kalman filtering with multiple hypothesis tracking to link the cell candidates at each time step. These hypotheses incorporate prior knowledge on vessel formation and cell proliferation rates. The association accuracy reaches 86.4% for the proposed algorithm, indicating that the proposed system is able to associate cells more accurately than existing approaches. Cell culture experiments in 3-D MFDs have shown considerable promise for improving biology research. The proposed system is expected to be a useful quantitative tool for potential microscopy problems of MFDs.

RNA Imaging with Dimeric Broccoli in Live Bacterial and Mammalian Cells

PubMed Central

Filonov, Grigory S.

2016-01-01

RNA spatial dynamics play a crucial role in cell physiology and thus the ability to monitor RNA localization in live cells can provide insight into important biological problems. This article focuses on imaging RNAs using an “RNA mimic of GFP”. This approach relies on a RNA aptamer, called dimeric Broccoli, which binds to and switches on the fluorescence of DFHBI, a small molecule mimicking the fluorophore in GFP. Dimeric Broccoli is tagged to heterologously expressed RNAs and upon DFHBI binding the fluorescent signal of dimeric Broccoli reports the transcript’s localization in cells. This protocol describes the process of validating the fluorescence of dimeric Broccoli-labeled transcripts in vitro and in cells, flow cytometry analysis to determine overall fluorescence levels in cells, and fluorescence imaging in bacterial and mammalian cells. Overall, the current protocol should be useful for researchers seeking to image high abundance RNAs, such as transcribed off the T7 promoter in bacteria or off Pol III-dependent promoters in mammalian cells. PMID:26995352

The legal status of embryos and implications for reproductive technologies and biotechnology research.

PubMed

Bowens, Krietta Kai

2006-01-01

The legal status of embryos in American law is changing. At present, most states do not afford embryos the same protections as a born person, but some states are attempting to change this standard. Granting embryos the same legal status as born human beings poses a significant problem for industries that work with embryos, especially fertility treatment facilities and scientists researching stem cell and gene therapy technologies. This paper describes the methods of defining embryos in American law, and discusses the implications of granting embryos the same rights as born persons for the reproductive technology and scientific research industries.

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

Thrall, Brian D.; Minard, Kevin R.; Teeguarden, Justin G.

A Cooperative Research and Development Agreement (CRADA) was sponsored by Battelle Memorial Institute (Battelle, Columbus), to initiate a collaborative research program across multiple Department of Energy (DOE) National Laboratories aimed at developing a suite of new capabilities for predictive toxicology. Predicting the potential toxicity of emerging classes of engineered nanomaterials was chosen as one of two focusing problems for this program. PNNL’s focus toward this broader goal was to refine and apply experimental and computational tools needed to provide quantitative understanding of nanoparticle dosimetry for in vitro cell culture systems, which is necessary for comparative risk estimates for different nanomaterialsmore » or biological systems. Research conducted using lung epithelial and macrophage cell models successfully adapted magnetic particle detection and fluorescent microscopy technologies to quantify uptake of various forms of engineered nanoparticles, and provided experimental constraints and test datasets for benchmark comparison against results obtained using an in vitro computational dosimetry model, termed the ISSD model. The experimental and computational approaches developed were used to demonstrate how cell dosimetry is applied to aid in interpretation of genomic studies of nanoparticle-mediated biological responses in model cell culture systems. The combined experimental and theoretical approach provides a highly quantitative framework for evaluating relationships between biocompatibility of nanoparticles and their physical form in a controlled manner.« less

Expression of keratinocyte growth factor (KGF) and its receptor in a middle-ear cavity problem.

PubMed

Yamamoto-Fukuda, Tomomi; Takahashi, Haruo; Koji, Takehiko

2012-01-01

To investigate the pathogenesis of one of the most troublesome conditions following ear surgery, a middle-ear cavity problem. Keratinocyte growth factor (KGF) and its receptor (KGFR), the ratio of proliferating epithelial cells using Ki-67, and the extent of infiltration of B cells and T cells were examined immunohistochemically in 10 ears with a cavity problem, 70 ears with cholesteatoma and 8 ears with normal skin at the retroauricular incision. KGF was positive in 40% of cavity problem specimens, 37.5% of normal skin specimens, and was positive in 88% of cholesteatoma specimens (cavity problem vs. cholesteatoma, p=0.0004). The positive rate of KGFR in the cavity problem group (33.3%) was between those in cholesteatoma (60%) and normal skin (0%). In contrast to the cholesteatoma specimens, a significantly smaller number of Ki-67 labeling index (LI) was detected in the cavity problem specimens. B cell LI was significantly higher but T cell LI was significantly lower in the cavity problem specimens than in the cholesteatoma group. Our present study indicated that the discordance of paracrine action between stromal KGF and epithelial KGFR with a large number of infiltrating B cells may play an important role in the pathogenesis of a cavity problem. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Apparatus for electroplating particles of small dimension

DOEpatents

Yu, C.M.; Illige, J.D.

1980-09-19

The thickness, uniformity, and surface smoothness requirements for surface coatings of glass microspheres for use as targets for laser fusion research are critical. Because of thier minute size, the microspheres are difficult to manipulate and control in electroplating systems. The electroplating apparatus of the present invention addresses these problems by providing a cathode cell having a cell chamber, a cathode and an anode electrically isolated from each other and connected to an electrical power source. During the plating process, the cathode is controllably vibrated along with solution pulse to maintain the particles in random free motion so as to attain the desired properties.

The knee meniscus: structure-function, pathophysiology, current repair techniques, and prospects for regeneration

PubMed Central

Makris, Eleftherios A.; Hadidi, Pasha; Athanasiou, Kyriacos A.

2011-01-01

Extensive scientific investigations in recent decades have established the anatomical, biomechanical, and functional importance that the meniscus holds within the knee joint. As a vital part of the joint, it acts to prevent the deterioration and degeneration of articular cartilage, and the onset and development of osteoarthritis. For this reason, research into meniscus repair has been the recipient of particular interest from the orthopedic and bioengineering communities. Current repair techniques are only effective in treating lesions located in the peripheral vascularized region of the meniscus. Healing lesions found in the inner avascular region, which functions under a highly demanding mechanical environment, is considered to be a significant challenge. An adequate treatment approach has yet to be established, though many attempts have been undertaken. The current primary method for treatment is partial meniscectomy, which commonly results in the progressive development of osteoarthritis. This drawback has shifted research interest towards the fields of biomaterials and bioengineering, where it is hoped that meniscal deterioration can be tackled with the help of tissue engineering. So far, different approaches and strategies have contributed to the in vitro generation of meniscus constructs, which are capable of restoring meniscal lesions to some extent, both functionally as well as anatomically. The selection of the appropriate cell source (autologous, allogeneic, or xenogeneic cells, or stem cells) is undoubtedly regarded as key to successful meniscal tissue engineering. Furthermore, a large variation of scaffolds for tissue engineering have been proposed and produced in experimental and clinical studies, although a few problems with these (e.g., byproducts of degradation, stress shielding) have shifted research interest towards new strategies (e.g., scaffoldless approaches, self-assembly). A large number of different chemical (e.g., TGF-β1, C-ABC) and mechanical stimuli (e.g., direct compression, hydrostatic pressure) have also been investigated, both in terms of encouraging functional tissue formation, as well as in differentiating stem cells. Even though the problems accompanying meniscus tissue engineering research are considerable, we are undoubtedly in the dawn of a new era, whereby recent advances in biology, engineering, and medicine are leading to the successful treatment of meniscal lesions. PMID:21764438

Lung cancer cell lines: Useless artifacts or invaluable tools for medical science?

PubMed Central

Gazdar, Adi F.; Gao, Boning; Minna, John D.

2011-01-01

Multiple cell lines (estimated at 300–400) have been established from human small cell (SCLC) and non-small cell lung cancers (NSCLC). These cell lines have been widely dispersed to and used by the scientific community worldwide, with over 8000 citations resulting from their study. However, there remains considerable skepticism on the part of the scientific community as to the validity of research resulting from their use. These questions center around the genomic instability of cultured cells, lack of differentiation of cultured cells and absence of stromal–vascular–inflammatory cell compartments. In this report we discuss the advantages and disadvantages of the use of cell lines, address the issues of instability and lack of differentiation. Perhaps the most important finding is that every important, recurrent genetic and epigenetic change including gene mutations, deletions, amplifications, translocations and methylation-induced gene silencing found in tumors has been identified in cell lines and vice versa. These “driver mutations” represented in cell lines offer opportunities for biological characterization and application to translational research. Another potential shortcoming of cell lines is the difficulty of studying multistage pathogenesis in vitro.To overcome this problem, we have developed cultures from central and peripheral airways that serve as models for the multistage pathogenesis of tumors arising in these two very different compartments. Finally the issue of cell line contamination must be addressed and safeguarded against. A full understanding of the advantages and shortcomings of cell lines is required for the investigator to derive the maximum benefit from their use. PMID:20079948

Flow cytometry and sorting

NASA Astrophysics Data System (ADS)

Yentsch, Clarice M.

For the first time oceanographers have a tool, known as a flow cytometer and sorter, which is useful for simultaneous measurement of multiple parameters of individual cells and particles at rapid rates. We are now able to exploit the fluorescent capability of pigments and stains as signals to quantify and separate subpopulations of cells and particles in the 1.0 to 150 μm size range. Analysis rates exceed 1000 cells per second and high sensitivity is attained using laser excitation.The addition of this new technology to the ocean sciences will enable researchers to address problems which were previously intractable. The first unit, funded by the Office of Naval Research and the National Science Foundation, will be at Bigelow Laboratory for Ocean Sciences in West Boothbay Harbor, Maine, in the laboratory of Clarice M. Yentsch and David A. Phinney. In anticipation of this award, a workshop course on flow cytometry (FCM) and sorting techniques was held from October 24 through November 1, 1982, at the Bermuda Biological Station.

Viral Vector-Based Innovative Approaches to Directly Abolishing Tumorigenic Pluripotent Stem Cells for Safer Regenerative Medicine.

PubMed

Mitsui, Kaoru; Ide, Kanako; Takahashi, Tomoyuki; Kosai, Ken-Ichiro

2017-06-16

Human pluripotent stem cells (hPSCs) are a promising source of regenerative material for clinical applications. However, hPSC transplant therapies pose the risk of teratoma formation and malignant transformation of undifferentiated remnants. These problems underscore the importance of developing technologies that completely prevent tumorigenesis to ensure safe clinical application. Research to date has contributed to establishing safe hPSC lines, improving the efficiency of differentiation induction, and indirectly ensuring the safety of products. Despite such efforts, guaranteeing the clinical safety of regenerative medicine products remains a key challenge. Given the intrinsic genome instability of hPSCs, selective growth advantage of cancer cells, and lessons learned through failures in previous attempts at hematopoietic stem cell gene therapy, conventional strategies are unlikely to completely overcome issues related to hPSC tumorigenesis. Researchers have recently embarked on studies aimed at locating and directly treating hPSC-derived tumorigenic cells. In particular, novel approaches to directly killing tumorigenic cells by transduction of suicide genes and oncolytic viruses are expected to improve the safety of hPSC-based therapy. This article discusses the current status and future perspectives of methods aimed at directly eradicating undifferentiated tumorigenic hPSCs, with a focus on viral vector transduction.

Implications of HLA-allele associations for the study of type IV drug hypersensitivity reactions.

PubMed

Sullivan, A; Watkinson, J; Waddington, J; Park, B K; Naisbitt, D J

2018-03-01

Type IV drug hypersensitivity remains an important clinical problem and an obstacle to the development of new drugs. Several forms of drug hypersensitivity are associated with expression of specific HLA alleles. Furthermore, drug-specific T-lymphocytes have been isolated from patients with reactions. Despite this, controversy remains as to how drugs interact with immune receptors to stimulate a T-cell response. Areas covered: This article reviews the pathways of T-cell activation by drugs and how the ever increasing number of associations between expression of HLA alleles and susceptibility to hypersensitivity is impacting on our research effort to understanding this form of iatrogenic disease. Expert opinion: For a drug to activate a T-cell, a complex is formed between HLA molecules, an HLA binding peptide, the drug and the T-cell receptor. T-cell responses can involve drugs and stable or reactive metabolites bound covalently or non-covalently to any component of this complex. Recent research has linked the HLA associations to the disease through the characterization of drug-specific T-cell responses restricted to specific alleles. However, there is now a need to identify the additional genetic or environment factors that determine susceptibility and use our increased knowledge to develop predictive immunogenicity tests that offer benefit to Pharma developing new drugs.

Cancer stem cells: a metastasizing menace!

PubMed

Bandhavkar, Saurabh

2016-04-01

Cancer is one of the leading causes of death worldwide, and is estimated to be a reason of death of more than 18 billion people in the coming 5 years. Progress has been made in diagnosis and treatment of cancer; however, a sound understanding of the underlying cell biology still remains an unsolved mystery. Current treatments include a combination of radiation, surgery, and/or chemotherapy. However, these treatments are not a complete cure, aimed simply at shrinking the tumor and in majority of cases, there is a relapse of tumor. Several evidences suggest the presence of cancer stem cells (CSCs) or tumor-initiating stem-like cells, a small population of cells present in the tumor, capable of self-renewal and generation of differentiated progeny. The presence of these CSCs can be attributed to the failure of cancer treatments as these cells are believed to exhibit therapy resistance. As a result, increasing attention has been given to CSC research to resolve the therapeutic problems related to cancer. Progress in this field of research has led to the development of novel strategies to treat several malignancies and has become a hot topic of discussion. In this review, we will briefly focus on the main characteristics, therapeutic implications, and perspectives of CSCs in cancer therapy. © 2016 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

Repair Mechanism of UV-damaged DNA in Xeroderma Pigmentosum | Center for Cancer Research

Cancer.gov

Xeroderma pigmentosum (XP) is a rare, inherited disorder characterized by extreme skin sensitivity to ultraviolet (UV) rays from sunlight. XP is caused by mutations in genes involved in nucleotide excision repair (NER) of damaged DNA. Normal cells are usually able to fix this damage before it leads to problems; however, the DNA damage is not repaired normally in patients with

Summaries of Research - Fiscal Year 1984.

DTIC Science & Technology

1984-09-01

findings suggest that the degradation of fibronectin may be important for potentially pathogenic gram-negative organisms to colonize oral soft tissues ...ACCOMPLISHMENTS (Continued) SCIENTIFIC INVESTIGATIONS DEPARTMENT (Continued) influencing the attachment of bacterial cells to soft tissues . Recent work has shown...of dental and oral health in Navy and Marine Corps populations andon problems of fleet an m , . -fielif tistry. s PERSONNEL -. As of 30 September 1984

From junior to senior: advice from the benefit of 20/20 hindsight

PubMed Central

Schmid, Sandra L.

2014-01-01

As the first recipient of both the Women in Cell Biology Junior and Senior Awards, I look back to identify key components that have provided the foundation for my successful research career. In retrospect, the three most important building blocks have been: identifying and pursing important problems; attracting and mentoring talented postdoctoral fellows and students; and establishing and nurturing strong collaborations. PMID:25360045

Computing through Scientific Abstractions in SysBioPS

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

Chin, George; Stephan, Eric G.; Gracio, Deborah K.

2004-10-13

Today, biologists and bioinformaticists have a tremendous amount of computational power at their disposal. With the availability of supercomputers, burgeoning scientific databases and digital libraries such as GenBank and PubMed, and pervasive computational environments such as the Grid, biologists have access to a wealth of computational capabilities and scientific data at hand. Yet, the rapid development of computational technologies has far exceeded the typical biologist’s ability to effectively apply the technology in their research. Computational sciences research and development efforts such as the Biology Workbench, BioSPICE (Biological Simulation Program for Intra-Cellular Evaluation), and BioCoRE (Biological Collaborative Research Environment) are importantmore » in connecting biologists and their scientific problems to computational infrastructures. On the Computational Cell Environment and Heuristic Entity-Relationship Building Environment projects at the Pacific Northwest National Laboratory, we are jointly developing a new breed of scientific problem solving environment called SysBioPSE that will allow biologists to access and apply computational resources in the scientific research context. In contrast to other computational science environments, SysBioPSE operates as an abstraction layer above a computational infrastructure. The goal of SysBioPSE is to allow biologists to apply computational resources in the context of the scientific problems they are addressing and the scientific perspectives from which they conduct their research. More specifically, SysBioPSE allows biologists to capture and represent scientific concepts and theories and experimental processes, and to link these views to scientific applications, data repositories, and computer systems.« less

Sickle cell disease in Africa: burden and research priorities

PubMed Central

Makani, J.; Williams, T. N.; Marsh, K.

2017-01-01

Sickle cell disease (SCD) has recently been recognised as a problem of major public-health significance by the World Health Organization. Despite the fact that >70% of sufferers live in Africa, expenditure on the related care and research in the continent is negligible, and most advances in the understanding and management of this condition have been based on research conducted in the North. In order to target limited resources, African countries need to focus research and interventions on areas that will lead to the maximum impact. This review details the epidemiological and clinical background of SCD, with an emphasis on Africa, before identifying the research priorities that will provide the necessary evidence base for improving the management of African patients. Malaria, bacterial and viral infections and cerebrovascular accidents are areas in which further research may lead to a significant improvement in SCD-related morbidity and mortality. As patients with high concentrations of foetal haemoglobin (HbF) appear to be protected from all but mild SCD, the various factors and pharmacological agents that might increase HbF levels need to be assessed in Africa, as options for interventions that would improve quality of life and reduce mortality. PMID:17244405

Culturally relevant inquiry-based laboratory module implementations in upper-division genetics and cell biology teaching laboratories.

PubMed

Siritunga, Dimuth; Montero-Rojas, María; Carrero, Katherine; Toro, Gladys; Vélez, Ana; Carrero-Martínez, Franklin A

2011-01-01

Today, more minority students are entering undergraduate programs than ever before, but they earn only 6% of all science or engineering PhDs awarded in the United States. Many studies suggest that hands-on research activities enhance students' interest in pursuing a research career. In this paper, we present a model for the implementation of laboratory research in the undergraduate teaching laboratory using a culturally relevant approach to engage students. Laboratory modules were implemented in upper-division genetics and cell biology courses using cassava as the central theme. Students were asked to bring cassava samples from their respective towns, which allowed them to compare their field-collected samples against known lineages from agricultural stations at the end of the implementation. Assessment of content and learning perceptions revealed that our novel approach allowed students to learn while engaged in characterizing Puerto Rican cassava. In two semesters, based on the percentage of students who answered correctly in the premodule assessment for content knowledge, there was an overall improvement of 66% and 55% at the end in the genetics course and 24% and 15% in the cell biology course. Our proposed pedagogical model enhances students' professional competitiveness by providing students with valuable research skills as they work on a problem to which they can relate.

Culturally Relevant Inquiry-Based Laboratory Module Implementations in Upper-Division Genetics and Cell Biology Teaching Laboratories

PubMed Central

Siritunga, Dimuth; Montero-Rojas, María; Carrero, Katherine; Toro, Gladys; Vélez, Ana; Carrero-Martínez, Franklin A.

2011-01-01

Today, more minority students are entering undergraduate programs than ever before, but they earn only 6% of all science or engineering PhDs awarded in the United States. Many studies suggest that hands-on research activities enhance students’ interest in pursuing a research career. In this paper, we present a model for the implementation of laboratory research in the undergraduate teaching laboratory using a culturally relevant approach to engage students. Laboratory modules were implemented in upper-division genetics and cell biology courses using cassava as the central theme. Students were asked to bring cassava samples from their respective towns, which allowed them to compare their field-collected samples against known lineages from agricultural stations at the end of the implementation. Assessment of content and learning perceptions revealed that our novel approach allowed students to learn while engaged in characterizing Puerto Rican cassava. In two semesters, based on the percentage of students who answered correctly in the premodule assessment for content knowledge, there was an overall improvement of 66% and 55% at the end in the genetics course and 24% and 15% in the cell biology course. Our proposed pedagogical model enhances students’ professional competitiveness by providing students with valuable research skills as they work on a problem to which they can relate. PMID:21885825

A comparison of sodium borohydride as a fuel for proton exchange membrane fuel cells and for direct borohydride fuel cells

NASA Astrophysics Data System (ADS)

Wee, Jung-Ho

Two types of fuel cell systems using NaBH 4 aqueous solution as a fuel are possible: the hydrogen/air proton exchange membrane fuel cell (PEMFC) which uses onsite H 2 generated via the NaBH 4 hydrolysis reaction (B-PEMFC) at the anode and the direct borohydride fuel cell (DBFC) system which directly uses NaBH 4 aqueous solution at the anode and air at the cathode. Recently, research on these two types of fuel cells has begun to attract interest due to the various benefits of this liquid fuel for fuel cell systems for portable applications. It might therefore be relevant at this stage to evaluate the relative competitiveness of the two fuel cells. Considering their current technologies and the high price of NaBH 4, this paper evaluated and analyzed the factors influencing the relative favorability of each type of fuel cell. Their relative competitiveness was strongly dependent on the extent of the NaBH 4 crossover. When considering the crossover in DBFC systems, the total costs of the B-PEMFC system were the most competitive among the fuel cell systems. On the other hand, if the crossover problem were to be completely overcome, the total cost of the DBFC system generating six electrons (6e-DBFC) would be very similar to that of the B-PEMFC system. The DBFC system generating eight electrons (8e-DBFC) became even more competitive if the problem of crossover can be overcome. However, in this case, the volume of NaBH 4 aqueous solution consumed by the DBFC was larger than that consumed by the B-PEMFC.

Spirally-patterned pinhole arrays for long-term fluorescence cell imaging.

PubMed

Koo, Bon Ung; Kang, YooNa; Moon, SangJun; Lee, Won Gu

2015-11-07

Fluorescence cell imaging using a fluorescence microscope is an extensively used technique to examine the cell nucleus, internal structures, and other cellular molecules with fluorescence response time and intensity. However, it is difficult to perform high resolution cell imaging for a long period of time with this technique due to necrosis and apoptosis depending on the type and subcellular location of the damage caused by phototoxicity. A large number of studies have been performed to resolve this problem, but researchers have struggled to meet the challenge between cellular viability and image resolution. In this study, we employ a specially designed disc to reduce cell damage by controlling total fluorescence exposure time without deterioration of the image resolution. This approach has many advantages such as, the apparatus is simple, cost-effective, and easily integrated into the optical pathway through a conventional fluorescence microscope.

Preparation of a Three-Dimensional Full Thickness Skin Equivalent.

PubMed

Reuter, Christian; Walles, Heike; Groeber, Florian

2017-01-01

In vitro test systems are a promising alternative to animal models. Due to the use of human cells in a three-dimensional arrangement that allows cell-cell or cell-matrix interactions these models may be more predictive for the human situation compared to animal models or two-dimensional cell culture systems. Especially for dermatological research, skin models such as epidermal or full-thickness skin equivalents (FTSE) are used for different applications. Although epidermal models provide highly standardized conditions for risk assessment, FTSE facilitate a cellular crosstalk between the dermal and epidermal layer and thus can be used as more complex models for the investigation of processes such as wound healing, skin development, or infectious diseases. In this chapter, we describe the generation and culture of an FTSE, based on a collagen type I matrix and provide troubleshooting tips for commonly encountered technical problems.

Effects of the physicochemical properties of gold nanostructures on cellular internalization

PubMed Central

Zhang, Jinchao; Wang, Paul C.; Liang, Xing-Jie

2015-01-01

Unique physicochemical properties of Au nanomaterials make them potential star materials in biomedical applications. However, we still know a little about the basic problem of what really matters in fabrication of Au nanomaterials which can get into biological systems, especially cells, with high efficiency. An understanding of how the physicochemical properties of Au nanomaterials affect their cell internalization is of significant interest. Studies devoted to clarify the functions of various properties of Au nanostructures such as size, shape and kinds of surface characteristics in cell internalization are under way. These fundamental investigations will give us a foundation for constructing Au nanomaterial-based biomedical devices in the future. In this review, we present the current advances and rationales in study of the relationship between the physicochemical properties of Au nanomaterials and cell uptake. We also provide a perspective on the Au nanomaterial-cell interaction research. PMID:26813673

Using the history of research on sickle-cell anemia to affect preservice teachers' conceptions of the nature of science

NASA Astrophysics Data System (ADS)

Howe, Eric M.

Preservice elementary teachers enrolled in an elective biology course participated in an eight-class unit of instruction based on the history of research in understanding the disease sickle-cell anemia. Students were introduced to the disease as a "mystery" for them to solve, and subsequently developed an understanding of the disease from several disciplines in biology (e.g., genetics, ecology, evolution, molecular biology). The unit involved open-ended problems in which students examined evidence and developed explanations in a manner analogous to the reasoning used by Anthony C. Allison and his colleagues during the early to middle part of the twentieth century. Throughout the unit, students were challenged to explicitly and reflectively connect their work with the historical material to more general conclusions about aspects of the nature of science. These aspects included (a) the nature of scientific theories, (b) the tentative nature of science, (c) the difference between scientific theories and laws, (d) the validity of observational methods in science, and (e) the subjective (theory-laden) nature of science. The research measured students' pre- and post-instruction views by using both an open-ended survey (VNOS) and follow-up, semi-structured interviews. The results indicated that an appreciable number of students underwent a change or enrichment in their views for some of the nature of science aspects. Moreover, change or enrichment in students' views was directly attributable to their work in the sickle-cell unit as evidenced from the specific examples students articulated in their post-instruction responses in support of their more informed views. In general, the findings of this research lend empirical support to the value of having students actively recapitulate the history of science to improve their nature of science conceptions. This is facilitated when the lessons challenge students to explicitly and reflectively develop views of the nature of science in tandem with their examinations of the problems taken from the history of science.

Discovery and development of new antibacterial drugs: learning from experience?

PubMed

Jackson, Nicole; Czaplewski, Lloyd; Piddock, Laura J V

2018-06-01

Antibiotic (antibacterial) resistance is a serious global problem and the need for new treatments is urgent. The current antibiotic discovery model is not delivering new agents at a rate that is sufficient to combat present levels of antibiotic resistance. This has led to fears of the arrival of a 'post-antibiotic era'. Scientific difficulties, an unfavourable regulatory climate, multiple company mergers and the low financial returns associated with antibiotic drug development have led to the withdrawal of many pharmaceutical companies from the field. The regulatory climate has now begun to improve, but major scientific hurdles still impede the discovery and development of novel antibacterial agents. To facilitate discovery activities there must be increased understanding of the scientific problems experienced by pharmaceutical companies. This must be coupled with addressing the current antibiotic resistance crisis so that compounds and ultimately drugs are delivered to treat the most urgent clinical challenges. By understanding the causes of the failures and successes of the pharmaceutical industry's research history, duplication of discovery programmes will be reduced, increasing the productivity of the antibiotic drug discovery pipeline by academia and small companies. The most important scientific issues to address are getting molecules into the Gram-negative bacterial cell and avoiding their efflux. Hence screening programmes should focus their efforts on whole bacterial cells rather than cell-free systems. Despite falling out of favour with pharmaceutical companies, natural product research still holds promise for providing new molecules as a basis for discovery.

Diamond, graphite, and graphene oxide nanoparticles decrease migration and invasiveness in glioblastoma cell lines by impairing extracellular adhesion

PubMed Central

Wierzbicki, Mateusz; Jaworski, Sławomir; Kutwin, Marta; Grodzik, Marta; Strojny, Barbara; Kurantowicz, Natalia; Zdunek, Krzysztof; Chodun, Rafał; Chwalibog, André; Sawosz, Ewa

2017-01-01

The highly invasive nature of glioblastoma is one of the most significant problems regarding the treatment of this tumor. Diamond nanoparticles (ND), graphite nanoparticles (NG), and graphene oxide nanoplatelets (nGO) have been explored for their biomedical applications, especially for drug delivery. The objective of this research was to assess changes in the adhesion, migration, and invasiveness of two glioblastoma cell lines, U87 and U118, after ND, NG, and nGO treatment. All treatments affected the cell surface structure, adhesion-dependent EGFR/AKT/mTOR, and β-catenin signaling pathways, decreasing the migration and invasiveness of both glioblastoma cell lines. The examined nanoparticles did not show strong toxicity but effectively deregulated cell migration. ND was effectively taken up by cells, whereas nGO and NG strongly interacted with the cell surface. These results indicate that nanoparticles could be used in biomedical applications as a low toxicity active compound for glioblastoma treatment. PMID:29042773

Diamond, graphite, and graphene oxide nanoparticles decrease migration and invasiveness in glioblastoma cell lines by impairing extracellular adhesion.

PubMed

Wierzbicki, Mateusz; Jaworski, Sławomir; Kutwin, Marta; Grodzik, Marta; Strojny, Barbara; Kurantowicz, Natalia; Zdunek, Krzysztof; Chodun, Rafał; Chwalibog, André; Sawosz, Ewa

2017-01-01

The highly invasive nature of glioblastoma is one of the most significant problems regarding the treatment of this tumor. Diamond nanoparticles (ND), graphite nanoparticles (NG), and graphene oxide nanoplatelets (nGO) have been explored for their biomedical applications, especially for drug delivery. The objective of this research was to assess changes in the adhesion, migration, and invasiveness of two glioblastoma cell lines, U87 and U118, after ND, NG, and nGO treatment. All treatments affected the cell surface structure, adhesion-dependent EGFR/AKT/mTOR, and β-catenin signaling pathways, decreasing the migration and invasiveness of both glioblastoma cell lines. The examined nanoparticles did not show strong toxicity but effectively deregulated cell migration. ND was effectively taken up by cells, whereas nGO and NG strongly interacted with the cell surface. These results indicate that nanoparticles could be used in biomedical applications as a low toxicity active compound for glioblastoma treatment.

[Primary culture of human normal epithelial cells].

PubMed

Tang, Yu; Xu, Wenji; Guo, Wanbei; Xie, Ming; Fang, Huilong; Chen, Chen; Zhou, Jun

2017-11-28

The traditional primary culture methods of human normal epithelial cells have disadvantages of low activity of cultured cells, the low cultivated rate and complicated operation. To solve these problems, researchers made many studies on culture process of human normal primary epithelial cell. In this paper, we mainly introduce some methods used in separation and purification of human normal epithelial cells, such as tissue separation method, enzyme digestion separation method, mechanical brushing method, red blood cell lysis method, percoll layered medium density gradient separation method. We also review some methods used in the culture and subculture, including serum-free medium combined with low mass fraction serum culture method, mouse tail collagen coating method, and glass culture bottle combined with plastic culture dish culture method. The biological characteristics of human normal epithelial cells, the methods of immunocytochemical staining, trypan blue exclusion are described. Moreover, the factors affecting the aseptic operation, the conditions of the extracellular environment, the conditions of the extracellular environment during culture, the number of differential adhesion, and the selection and dosage of additives are summarized.

Introduction to Single-Cell RNA Sequencing.

PubMed

Olsen, Thale Kristin; Baryawno, Ninib

2018-04-01

During the last decade, high-throughput sequencing methods have revolutionized the entire field of biology. The opportunity to study entire transcriptomes in great detail using RNA sequencing (RNA-seq) has fueled many important discoveries and is now a routine method in biomedical research. However, RNA-seq is typically performed in "bulk," and the data represent an average of gene expression patterns across thousands to millions of cells; this might obscure biologically relevant differences between cells. Single-cell RNA-seq (scRNA-seq) represents an approach to overcome this problem. By isolating single cells, capturing their transcripts, and generating sequencing libraries in which the transcripts are mapped to individual cells, scRNA-seq allows assessment of fundamental biological properties of cell populations and biological systems at unprecedented resolution. Here, we present the most common scRNA-seq protocols in use today and the basics of data analysis and discuss factors that are important to consider before planning and designing an scRNA-seq project. © 2018 by John Wiley & Sons, Inc. Copyright © 2018 John Wiley & Sons, Inc.

Visualizing Cell Architecture and Molecular Location Using Soft X-Ray Tomography and Correlated Cryo-Light Microscopy

PubMed Central

McDermott, Gerry; Le Gros, Mark A.; Larabell, Carolyn A.

2012-01-01

Living cells are structured to create a range of microenvironments that support specific chemical reactions and processes. Understanding how cells function therefore requires detailed knowledge of both the subcellular architecture and the location of specific molecules within this framework. Here we review the development of two correlated cellular imaging techniques that fulfill this need. Cells are first imaged using cryogenic fluorescence microscopy to determine the location of molecules of interest that have been labeled with fluorescent tags. The same specimen is then imaged using soft X-ray tomography to generate a high-contrast, 3D reconstruction of the cells. Data from the two modalities are then combined to produce a composite, information-rich view of the cell. This correlated imaging approach can be applied across the spectrum of problems encountered in cell biology, from basic research to biotechnological and biomedical applications such as the optimization of biofuels and the development of new pharmaceuticals. PMID:22242730

Tissue engineering.

PubMed

Katari, Ravi S; Peloso, Andrea; Orlando, Giuseppe

2014-01-01

Ultimately much work remains to be done in the companion fields of biomaterials and stem cells. Nonetheless, the monumental progress in TE that has been reported in the studies summarized here demonstrates that regenerative approaches to problems in general surgery need to be explored in more depth. Furthermore, the surgical disciplines of reconstruction and transplantation need to recognize their research counterparts in TE, given its potential to actualize freedom from immunosuppression, one of the most elusive goals in modern surgery. The engineering and proliferation of autologous cells, tissues, and organs ex vivo before surgical operation can significantly reduce the obstacles current practitioners are intimately familiar with: donor site morbidity and immunologic rejection. Therefore, in addition to the truly exciting research and development prospects and implications for the commercial sector, patients with end-stage diseases and debilitating injury stand to gain the most from clinically adapted TE therapies.

Social science in a stem cell laboratory: what happened when social and life sciences met.

PubMed

Stacey, Glyn; Stephens, Neil

2012-01-01

We describe the experience of conducting intensive social science research at the UK Stem Cell Bank from the viewpoint of both the person conducting the social science research and the Director of the Bank. We detail the initial misunderstandings and concerns held by both and the problems these caused. Then we describe how the relationship developed as the project progressed and shared benefits became apparent. Finally, while acknowledging potential areas of tension between the life and social sciences, we suggest further interaction between the disciplines would prove beneficial for both and speculate as to how this may be achieved. In the discussion we identify a set of learning points from our experience and definitions of social science terminology that may help to inform future engagements between life and social scientists.

Bioengineering/Biophysicist Post-doctoral Fellow | Center for Cancer Research

Cancer.gov

A post-doctoral fellow position is available in the Tissue Morphodynamics Unit headed by Dr. Kandice Tanner at the National Cancer Institute. The Tanner lab combines biophysical and cell biological approaches to understand the interplay between tissue architecture and metastasis. We use a combination of imaging modalities, cell biology and animal models. It is expected that as a member of this lab, one will have an opportunity to be exposed to all these areas. We value a vibrant and collaborative environment where lab members share ideas, reagents and expertise and want to work on fundamental problems in the establishment of metastatic lesions. Our lab is located in the NIH main campus in Bethesda. The research facilities at NIH are outstanding and the lab has state-of-the-art equipment such as multi-photon and confocal microscopes, FACS facilities and animal vivarium.

Dye-sensitized solar cells using ionic liquids as redox mediator

NASA Astrophysics Data System (ADS)

Denizalti, Serpil; Ali, Abdulrahman Khalaf; Ela, Çağatay; Ekmekci, Mesut; Erten-Ela, Sule

2018-01-01

In this research, the influence of ionic liquid on the conversion efficiency, incident photons to converted electrons (IPCE) and performance of fabricated solar cell was investigated using various ionic liquids. Ionic liquids with different substituents and ions were prepared and used as redox mediators in dye-sensitized solar cells (DSSCs). Ionic liquids were characterized 1H and 13C NMR spectra. We practically investigated the performance of ionic liquid salts were used as the mobile ions and found that the efficiencies of DSSCs were increased up to 40% comparing commercial electrolyte system. The ionic liquid compounds were incorporated in DSSCs to obtain an efficient charge transfer, solving the corrosion problem of platinum layer in counter electrode compared to commercial electrolyte.

Fluorine-19 MRI Contrast Agents for Cell Tracking and Lung Imaging

PubMed Central

Fox, Matthew S.; Gaudet, Jeffrey M.; Foster, Paula J.

2015-01-01

Fluorine-19 (19F)-based contrast agents for magnetic resonance imaging stand to revolutionize imaging-based research and clinical trials in several fields of medical intervention. First, their use in characterizing in vivo cell behavior may help bring cellular therapy closer to clinical acceptance. Second, their use in lung imaging provides novel noninvasive interrogation of the ventilated airspaces without the need for complicated, hard-to-distribute hardware. This article reviews the current state of 19F-based cell tracking and lung imaging using magnetic resonance imaging and describes the link between the methods across these fields and how they may mutually benefit from solutions to mutual problems encountered when imaging 19F-containing compounds, as well as hardware and software advancements. PMID:27042089

Electrocatalysts by atomic layer deposition for fuel cell applications

DOE PAGES

Cheng, Niancai; Shao, Yuyan; Liu, Jun; ...

2016-01-22

Here, fuel cells are a promising technology solution for reliable and clean energy because they offer high energy conversion efficiency and low emission of pollutants. However, high cost and insufficient durability are considerable challenges for widespread adoption of polymer electrolyte membrane fuel cells (PEMFCs) in practical applications. Current PEMFCs catalysts have been identified as major contributors to both the high cost and limited durability. Atomic layer deposition (ALD) is emerging as a powerful technique for solving these problems due to its exclusive advantages over other methods. In this review, we summarize recent developments of ALD in PEMFCs with a focusmore » on design of materials for improved catalyst activity and durability. New research directions and future trends have also been discussed.« less

Maternal cell phone and cordless phone use during pregnancy and behaviour problems in 5-year-old children.

PubMed

Guxens, Mònica; van Eijsden, Manon; Vermeulen, Roel; Loomans, Eva; Vrijkotte, Tanja G M; Komhout, Hans; van Strien, Rob T; Huss, Anke

2013-05-01

A previous study found an association between maternal cell phone use during pregnancy and maternal-reported child behaviour problems at age 7. Together with cell phones, cordless phones represent the main exposure source of radiofrequency-electromagnetic fields to the head. Therefore, we assessed the association between maternal cell phone and cordless phone use during pregnancy and teacher-reported and maternal-reported child behaviour problems at age 5. The study was embedded in the Amsterdam Born Children and their Development study, a population-based birth cohort study in Amsterdam, the Netherlands (2003-2004). Teachers and mothers reported child behaviour problems using the Strength and Difficulties Questionnaire at age 5. Maternal cell phone and cordless phone use during pregnancy was asked when children were 7 years old. A total of 2618 children were included. As compared to non-users, those exposed to prenatal cell phone use showed an increased but non-significant association of having teacher-reported overall behaviour problems, although without dose-response relationship with the number of calls (OR=2.12 (95% CI 0.95 to 4.74) for <1 call/day, OR=1.58 (95% CI 0.69 to 3.60) for 1-4 calls/day and OR=2.04 (95% CI 0.86 to 4.80) for ≥5 calls/day). ORs for having teacher-reported overall behaviour problems across categories of cordless phone use were below 1 or close to unity. Associations of maternal cell phone and cordless phone use with maternal-reported overall behaviour problems remained non-significant. Non-significant associations were found for the specific behaviour problem subscales. Our results do not suggest that maternal cell phone or cordless phone use during pregnancy increases the odds of behaviour problems in their children.

The analysis method of the DRAM cell pattern hotspot

NASA Astrophysics Data System (ADS)

Lee, Kyusun; Lee, Kweonjae; Chang, Jinman; Kim, Taeheon; Han, Daehan; Hong, Aeran; Kim, Yonghyeon; Kang, Jinyoung; Choi, Bumjin; Lee, Joosung; Lee, Jooyoung; Hong, Hyeongsun; Lee, Kyupil; Jin, Gyoyoung

2015-03-01

It is increasingly difficult to determine degree of completion of the patterning and the distribution at the DRAM Cell Patterns. When we research DRAM Device Cell Pattern, there are three big problems currently, it is as follows. First, due to etch loading, it is difficult to predict the potential defect. Second, due to under layer topology, it is impossible to demonstrate the influence of the hotspot. Finally, it is extremely difficult to predict final ACI pattern by the photo simulation, because current patterning process is double patterning technology which means photo pattern is completely different from final etch pattern. Therefore, if the hotspot occurs in wafer, it is very difficult to find it. CD-SEM is the most common pattern measurement tool in semiconductor fabrication site. CD-SEM is used to accurately measure small region of wafer pattern primarily. Therefore, there is no possibility of finding places where unpredictable defect occurs. Even though, "Current Defect detector" can measure a wide area, every chip has same pattern issue, the detector cannot detect critical hotspots. Because defect detecting algorithm of bright field machine is based on image processing, if same problems occur on compared and comparing chip, the machine cannot identify it. Moreover this instrument is not distinguished the difference of distribution about 1nm~3nm. So, "Defect detector" is difficult to handle the data for potential weak point far lower than target CD. In order to solve those problems, another method is needed. In this paper, we introduce the analysis method of the DRAM Cell Pattern Hotspot.

Recommendation of short tandem repeat profiling for authenticating human cell lines, stem cells, and tissues

PubMed Central

Barallon, Rita; Bauer, Steven R.; Butler, John; Capes-Davis, Amanda; Dirks, Wilhelm G.; Furtado, Manohar; Kline, Margaret C.; Kohara, Arihiro; Los, Georgyi V.; MacLeod, Roderick A. F.; Masters, John R. W.; Nardone, Mark; Nardone, Roland M.; Nims, Raymond W.; Price, Paul J.; Reid, Yvonne A.; Shewale, Jaiprakash; Sykes, Gregory; Steuer, Anton F.; Storts, Douglas R.; Thomson, Jim; Taraporewala, Zenobia; Alston-Roberts, Christine; Kerrigan, Liz

2010-01-01

Cell misidentification and cross-contamination have plagued biomedical research for as long as cells have been employed as research tools. Examples of misidentified cell lines continue to surface to this day. Efforts to eradicate the problem by raising awareness of the issue and by asking scientists voluntarily to take appropriate actions have not been successful. Unambiguous cell authentication is an essential step in the scientific process and should be an inherent consideration during peer review of papers submitted for publication or during review of grants submitted for funding. In order to facilitate proper identity testing, accurate, reliable, inexpensive, and standardized methods for authentication of cells and cell lines must be made available. To this end, an international team of scientists is, at this time, preparing a consensus standard on the authentication of human cells using short tandem repeat (STR) profiling. This standard, which will be submitted for review and approval as an American National Standard by the American National Standards Institute, will provide investigators guidance on the use of STR profiling for authenticating human cell lines. Such guidance will include methodological detail on the preparation of the DNA sample, the appropriate numbers and types of loci to be evaluated, and the interpretation and quality control of the results. Associated with the standard itself will be the establishment and maintenance of a public STR profile database under the auspices of the National Center for Biotechnology Information. The consensus standard is anticipated to be adopted by granting agencies and scientific journals as appropriate methodology for authenticating human cell lines, stem cells, and tissues. PMID:20614197

Recommendation of short tandem repeat profiling for authenticating human cell lines, stem cells, and tissues.

PubMed

Barallon, Rita; Bauer, Steven R; Butler, John; Capes-Davis, Amanda; Dirks, Wilhelm G; Elmore, Eugene; Furtado, Manohar; Kline, Margaret C; Kohara, Arihiro; Los, Georgyi V; MacLeod, Roderick A F; Masters, John R W; Nardone, Mark; Nardone, Roland M; Nims, Raymond W; Price, Paul J; Reid, Yvonne A; Shewale, Jaiprakash; Sykes, Gregory; Steuer, Anton F; Storts, Douglas R; Thomson, Jim; Taraporewala, Zenobia; Alston-Roberts, Christine; Kerrigan, Liz

2010-10-01

Cell misidentification and cross-contamination have plagued biomedical research for as long as cells have been employed as research tools. Examples of misidentified cell lines continue to surface to this day. Efforts to eradicate the problem by raising awareness of the issue and by asking scientists voluntarily to take appropriate actions have not been successful. Unambiguous cell authentication is an essential step in the scientific process and should be an inherent consideration during peer review of papers submitted for publication or during review of grants submitted for funding. In order to facilitate proper identity testing, accurate, reliable, inexpensive, and standardized methods for authentication of cells and cell lines must be made available. To this end, an international team of scientists is, at this time, preparing a consensus standard on the authentication of human cells using short tandem repeat (STR) profiling. This standard, which will be submitted for review and approval as an American National Standard by the American National Standards Institute, will provide investigators guidance on the use of STR profiling for authenticating human cell lines. Such guidance will include methodological detail on the preparation of the DNA sample, the appropriate numbers and types of loci to be evaluated, and the interpretation and quality control of the results. Associated with the standard itself will be the establishment and maintenance of a public STR profile database under the auspices of the National Center for Biotechnology Information. The consensus standard is anticipated to be adopted by granting agencies and scientific journals as appropriate methodology for authenticating human cell lines, stem cells, and tissues.

Alginate Encapsulation of Pluripotent Stem Cells Using a Co-axial Nozzle

PubMed Central

Horiguchi, Ikki; Sakai, Yasuyuki

2015-01-01

Pluripotent stem cells (PS cells) are the focus of intense research due to their role in regenerative medicine and drug screening. However, the development of a mass culture system would be required for using PS cells in these applications. Suspension culture is one promising culture method for the mass production of PS cells, although some issues such as controlling aggregation and limiting shear stress from the culture medium are still unsolved. In order to solve these problems, we developed a method of calcium alginate (Alg-Ca) encapsulation using a co-axial nozzle. This method can control the size of the capsules easily by co-flowing N2 gas. The controllable capsule diameter must be larger than 500 µm because too high a flow rate of N2 gas causes the breakdown of droplets and thus heterogeneous-sized capsules. Moreover, a low concentration of Alg-Na and CaCl2 causes non-spherical capsules. Although an Alg-Ca capsule without a coating of Alg-PLL easily dissolves enabling the collection of cells, they can also potentially leak out from capsules lacking an Alg-PLL coating. Indeed, an alginate-PLL coating can prevent cellular leakage but is also hard to break. This technology can be used to research the stem cell niche as well as the mass production of PS cells because encapsulation can modify the micro-environment surrounding cells including the extracellular matrix and the concentration of secreted factors. PMID:26168084

A problem-solving education intervention in caregivers and patients during allogeneic hematopoietic stem cell transplantation.

PubMed

Bevans, Margaret; Wehrlen, Leslie; Castro, Kathleen; Prince, Patricia; Shelburne, Nonniekaye; Soeken, Karen; Zabora, James; Wallen, Gwenyth R

2014-05-01

The aim of this study was to determine the effect of problem-solving education on self-efficacy and distress in informal caregivers of allogeneic hematopoietic stem cell transplantation patients. Patient/caregiver teams attended three 1-hour problem-solving education sessions to help cope with problems during hematopoietic stem cell transplantation. Primary measures included the Cancer Self-Efficacy Scale-transplant and Brief Symptom Inventory-18. Active caregivers reported improvements in self-efficacy (p < 0.05) and distress (p < 0.01) post-problem-solving education; caregiver responders also reported better health outcomes such as fatigue. The effect of problem-solving education on self-efficacy and distress in hematopoietic stem cell transplantation caregivers supports its inclusion in future interventions to meet the multifaceted needs of this population.

Recommendations for managing cutaneous disorders associated with advancing age

PubMed Central

Humbert, Philippe; Dréno, Brigitte; Krutmann, Jean; Luger, Thomas Anton; Triller, Raoul; Meaume, Sylvie; Seité, Sophie

2016-01-01

The increasingly aged population worldwide means more people are living with chronic diseases, reduced autonomy, and taking various medications. Health professionals should take these into consideration when managing dermatological problems in elderly patients. Accordingly, current research is investigating the dermatological problems associated with the loss of cutaneous function with age. As cell renewal slows, the physical and chemical barrier function declines, cutaneous permeability increases, and the skin becomes increasingly vulnerable to external factors. In geriatric dermatology, the consequences of cutaneous aging lead to xerosis, skin folding, moisture-associated skin damage, and impaired wound healing. These problems pose significant challenges for both the elderly and their carers. Most often, nurses manage skin care in the elderly. However, until recently, little attention has been paid to developing appropriate, evidence-based, skincare protocols. The objective of this paper is to highlight common clinical problems with aging skin and provide some appropriate advice on cosmetic protocols for managing them. A review of the literature from 2004 to 2014 using PubMed was performed by a working group of six European dermatologists with clinical and research experience in dermatology. Basic topical therapy can restore and protect skin barrier function, which relieves problems associated with xerosis, prevents aggravating moisture-associated skin damage, and enhances quality of life. In conclusion, the authors provide physicians with practical recommendations to assist them in implementing basic skin care for the elderly in an integrated care approach. PMID:26929610

Extending the knowledge in histochemistry and cell biology.

PubMed

Heupel, Wolfgang-Moritz; Drenckhahn, Detlev

2010-01-01

Central to modern Histochemistry and Cell Biology stands the need for visualization of cellular and molecular processes. In the past several years, a variety of techniques has been achieved bridging traditional light microscopy, fluorescence microscopy and electron microscopy with powerful software-based post-processing and computer modeling. Researchers now have various tools available to investigate problems of interest from bird's- up to worm's-eye of view, focusing on tissues, cells, proteins or finally single molecules. Applications of new approaches in combination with well-established traditional techniques of mRNA, DNA or protein analysis have led to enlightening and prudent studies which have paved the way toward a better understanding of not only physiological but also pathological processes in the field of cell biology. This review is intended to summarize articles standing for the progress made in "histo-biochemical" techniques and their manifold applications.

[Advances in application of clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 system in stem cells research].

PubMed

Sun, S J; Huo, J H; Geng, Z J; Sun, X Y; Fu, X B

2018-04-20

Gene engineering has attracted worldwide attention because of its ability of precise location of disease mutations in genome. As a new gene editing technology, clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system is simple, fast, and accurate to operate at a specific gene site. It overcomes the long-standing problem of conventional operation. At the same time, stem cells are a good foundation for establishing disease model in vitro. Therefore, it has great significance to combine stem cells with the rapidly developing gene manipulation techniques. In this review, we mainly focus on the mechanism of CRISPR/Cas9 technology and its application in stem cell genomic editing, so as to pave the way for promoting rapid application and development of CRISPR/Cas9 technology.

[Laser microdissection for biology and medicine].

PubMed

Podgornyĭ, O V; Lazarev, V N; Govorun, V M

2012-01-01

For routine extraction of DNA, RNA, proteins and metabolites, small tissue pieces are placed into lysing solution. These tissue pieces in general contain different cell types. For this reason, lysate contains components of different cell types, which complicates the interpretation of molecular analysis results. The laser microdissection allows overcoming this trouble. The laser microdissection is a method to procure tissue samples contained defined cell subpopulations, individual cells and even subsellular components under direct microscopic visualization. Collected samples can be undergone to different downstream molecular assays: DNA analysis, RNA transcript profiling, cDNA library generation and gene expression analysis, proteomic analysis and metabolite profiling. The laser microdissection has wide applications in oncology (research and routine), cellular and molecular biology, biochemistry and forensics. This paper reviews the principles of different laser microdissection instruments, examples of laser microdissection application and problems of sample preparation for laser microdissection.

Bioprocess Intensification of Beer Fermentation Using Immobilised Cells

NASA Astrophysics Data System (ADS)

Verbelen, Pieter J.; Nedović, Viktor A.; Manojlović, Verica; Delvaux, Freddy R.; Laskošek-Čukalović, Ida; Bugarski, Branko; Willaert, Ronnie

Beer production with immobilised yeast has been the subject of research for approximately 30 years but has so far found limited application in the brewing industry, due to engineering problems, unrealised cost advantages, microbial contaminations and an unbalanced beer flavor (Linko et al. 1998; Brányik et al. 2005; Willaert and Nedović 2006). The ultimate aim of this research is the production of beer of desired quality within 1-3 days. Traditional beer fermentation systems use freely suspended yeast cells to ferment wort in an unstirred batch reactor. The primary fermentation takes approximately 7 days with a subsequent secondary fermentation (maturation) of several weeks. A batch culture system employing immobilization could benefit from an increased rate of fermentation. However, it appears that in terms of increasing productivity, a continuous fermentation system with immobilization would be the best method (Verbelen et al. 2006). An important issue of the research area is whether beer can be produced by immobilised yeast in continuous culture with the same characteristic as the traditional method.

Sterilization of polydimethylsiloxane surface with Chinese herb extract: a new antibiotic mechanism of chlorogenic acid

PubMed Central

Ren, Song; Wu, Ming; Guo, Jiayu; Zhang, Wang; Liu, Xiaohan; Sun, Lili; Holyst, Robert; Hou, Sen; Fang, Yongchun; Feng, Xizeng

2015-01-01

Coating of polydimethylsiloxane (PDMS) surface with a traditional Chinese herb extract chlorogenic acid (CA) solves the contemporary problem of sterilization of PDMS surface. The E. coli grows slower and has a higher death rate on the CA-coated PDMS surfaces. A smoother morphology of these E. coli cell wall is observed by atomic force microscopy (AFM). Unlike the reported mechanism, where CA inhibits bacterial growth by damaging the cell membrane in the bulk solution, we find the CA-coated PDMS surface also decreases the stiffness of the cell wall. A decrease in the Young’s modulus of the cell wall from 3 to 0.8 MPa is reported. Unexpectedly, the CA effect on the swarming ability and the biofilm stability of the bacteria can be still observed, even after they have been removed from the CA environment, indicating a decrease in their resistance to antibiotics for a prolonged time. The CA-coated PDMS surface shows better antibiotic effect against three types of both Gram-positive and Gran-negative bacteria than the gentamicin-coated PDMS surface. Coating of CA on PDMS surface not only solves the problem of sterilization of PDMS surface, but also shines light on the application of Chinese traditional herbs in scientific research. PMID:25993914

Sterilization of polydimethylsiloxane surface with Chinese herb extract: a new antibiotic mechanism of chlorogenic acid.

PubMed

Ren, Song; Wu, Ming; Guo, Jiayu; Zhang, Wang; Liu, Xiaohan; Sun, Lili; Holyst, Robert; Hou, Sen; Fang, Yongchun; Feng, Xizeng

2015-05-21

Coating of polydimethylsiloxane (PDMS) surface with a traditional Chinese herb extract chlorogenic acid (CA) solves the contemporary problem of sterilization of PDMS surface. The E. coli grows slower and has a higher death rate on the CA-coated PDMS surfaces. A smoother morphology of these E. coli cell wall is observed by atomic force microscopy (AFM). Unlike the reported mechanism, where CA inhibits bacterial growth by damaging the cell membrane in the bulk solution, we find the CA-coated PDMS surface also decreases the stiffness of the cell wall. A decrease in the Young's modulus of the cell wall from 3 to 0.8 MPa is reported. Unexpectedly, the CA effect on the swarming ability and the biofilm stability of the bacteria can be still observed, even after they have been removed from the CA environment, indicating a decrease in their resistance to antibiotics for a prolonged time. The CA-coated PDMS surface shows better antibiotic effect against three types of both Gram-positive and Gran-negative bacteria than the gentamicin-coated PDMS surface. Coating of CA on PDMS surface not only solves the problem of sterilization of PDMS surface, but also shines light on the application of Chinese traditional herbs in scientific research.

The functional basis of adaptive evolution in chemostats.

PubMed

Gresham, David; Hong, Jungeui

2015-01-01

Two of the central problems in biology are determining the molecular basis of adaptive evolution and understanding how cells regulate their growth. The chemostat is a device for culturing cells that provides great utility in tackling both of these problems: it enables precise control of the selective pressure under which organisms evolve and it facilitates experimental control of cell growth rate. The aim of this review is to synthesize results from studies of the functional basis of adaptive evolution in long-term chemostat selections using Escherichia coli and Saccharomyces cerevisiae. We describe the principle of the chemostat, provide a summary of studies of experimental evolution in chemostats, and use these studies to assess our current understanding of selection in the chemostat. Functional studies of adaptive evolution in chemostats provide a unique means of interrogating the genetic networks that control cell growth, which complements functional genomic approaches and quantitative trait loci (QTL) mapping in natural populations. An integrated approach to the study of adaptive evolution that accounts for both molecular function and evolutionary processes is critical to advancing our understanding of evolution. By renewing efforts to integrate these two research programs, experimental evolution in chemostats is ideally suited to extending the functional synthesis to the study of genetic networks. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

Human cells and cell cultures: availability, authentication and future prospects.

PubMed

Hay, R J

1996-09-01

The availability of well characterized, viable human cells, tissues and cell lines along with pertinent data on the specific patient donors is a prerequisite for much current transplantation and biomedical research. In the USA, institutional and multi-center networks have been established for provision of primary human cells and tissues to qualified clinicians and research scientists. Monetary support derives from government, university, institutional and fee sources. Problems involved include concern for the rights and privacy of tissue donors, cultural reservations relating to tissue provision, the need for safe and expeditious transport, short term survival and limited supply, adequate correlation of patient data with samples provided, presence of infectious viruses and microorganisms, as well as state or government regulations regarding national or international shipping. The use of human cell lines with continuous or even somewhat limited doubling potentials overcomes many of the above difficulties. National cell banks have been established to provide reference lines for use by multiple investigators. Use of such cell lines assures improved research comparability both geographically and with time. Authentication procedures are critically important for all of these programs. Verification of tissue types and conditions is required through histological, biochemical and immunological assays. Tests for microbial and viral contaminants must be applied. In addition to such procedures utilized for tissues, with cell lines the banking agency must also verify species and where possible identity, properties and functions. The literature is replete with descriptions documenting incorrect identifications and infections of proliferating cell strains used for research. The availability of viable tissue through local sources and distribution agencies in the USA is becoming more commonplace even including full family participation and collection of related, detailed histories. Increased support for this developmental activity is needed, coupled with provision of blood and normal cells and cell lines from family members in many disease categories. Modern techniques, new and improved culture ware, serum-free media, reagents such as growth, adherence and transfer factors will permit isolation, propagation and wide spread distribution not only of human tumor cells but also normal and functional human cells of most renewing and expanding tissue types. Hybridization and immortalization techniques are enhancing this capability such that virtually all human cell types should be available for short or longer-term propagation and study in the foreseeable future.

Colour helps to solve the binocular matching problem

PubMed Central

den Ouden, HEM; van Ee, R; de Haan, EHF

2005-01-01

The spatial differences between the two retinal images, called binocular disparities, can be used to recover the three-dimensional (3D) aspects of a scene. The computation of disparity depends upon the correct identification of corresponding features in the two images. Understanding what image features are used by the brain to solve this binocular matching problem is an important issue in research on stereoscopic vision. The role of colour in binocular vision is controversial and it has been argued that colour is ineffective in achieving binocular vision. In the current experiment subjects were required to indicate the amount of perceived depth. The stimulus consisted of an array of fronto-parallel bars uniformly distributed in a constant sized volume. We studied the perceived depth in those 3D stimuli by manipulating both colour (monochrome, trichrome) and luminance (congruent, incongruent). Our results demonstrate that the amount of perceived depth was influenced by colour, indicating that the visual system uses colour to achieve binocular matching. Physiological data have revealed cortical cells in macaque V2 that are tuned both to binocular disparity and to colour. We suggest that one of the functional roles of these cells may be to help solve the binocular matching problem. PMID:15975983

Colour helps to solve the binocular matching problem.

PubMed

den Ouden, H E M; van Ee, R; de Haan, E H F

2005-09-01

The spatial differences between the two retinal images, called binocular disparities, can be used to recover the three-dimensional (3D) aspects of a scene. The computation of disparity depends upon the correct identification of corresponding features in the two images. Understanding what image features are used by the brain to solve this binocular matching problem is an important issue in research on stereoscopic vision. The role of colour in binocular vision is controversial and it has been argued that colour is ineffective in achieving binocular vision. In the current experiment subjects were required to indicate the amount of perceived depth. The stimulus consisted of an array of fronto-parallel bars uniformly distributed in a constant sized volume. We studied the perceived depth in those 3D stimuli by manipulating both colour (monochrome, trichrome) and luminance (congruent, incongruent). Our results demonstrate that the amount of perceived depth was influenced by colour, indicating that the visual system uses colour to achieve binocular matching. Physiological data have revealed cortical cells in macaque V2 that are tuned both to binocular disparity and to colour. We suggest that one of the functional roles of these cells may be to help solve the binocular matching problem.

The Emerging Cell Biology of Thyroid Stem Cells

PubMed Central

Latif, Rauf; Minsky, Noga C.; Ma, Risheng

2011-01-01

Context: Stem cells are undifferentiated cells with the property of self-renewal and give rise to highly specialized cells under appropriate local conditions. The use of stem cells in regenerative medicine holds great promise for the treatment of many diseases, including those of the thyroid gland. Evidence Acquisition: This review focuses on the progress that has been made in thyroid stem cell research including an overview of cellular and molecular events (most of which were drawn from the period 1990–2011) and discusses the remaining problems encountered in their differentiation. Evidence Synthesis: Protocols for the in vitro differentiation of embryonic stem cells, based on normal developmental processes, have generated thyroid-like cells but without full thyrocyte function. However, agents have been identified, including activin A, insulin, and IGF-I, which are able to stimulate the generation of thyroid-like cells in vitro. In addition, thyroid stem/progenitor cells have been identified within the normal thyroid gland and within thyroid cancers. Conclusions: Advances in thyroid stem cell biology are providing not only insight into thyroid development but may offer therapeutic potential in thyroid cancer and future thyroid cell replacement therapy. PMID:21778219

Research in Optical Sciences

DTIC Science & Technology

1990-03-12

where this is not so (see, e.g., the Jaynes - Cummings problem). This is why this model , and the closely related micromaser, remain exceedingly important...55 one calculates the plane- wave spectrum ( without 7.), one must arbitrarily impose nearly zero phase mismatch to obtain a similar spectrum.3" 2.7...taking approximately 3 CPU minutes. To model the intentionally introduced astigmatism, a phase term was added to the input wavefront at the cell entrance

From junior to senior: advice from the benefit of 20/20 hindsight.

PubMed

Schmid, Sandra L

2014-11-01

As the first recipient of both the Women in Cell Biology Junior and Senior Awards, I look back to identify key components that have provided the foundation for my successful research career. In retrospect, the three most important building blocks have been: identifying and pursing important problems; attracting and mentoring talented postdoctoral fellows and students; and establishing and nurturing strong collaborations. © 2014 Schmid.

Joint actions of environmental nonionizing electromagnetic fields and chemical pollution in cancer promotion.

PubMed Central

Adey, W R

1990-01-01

Studies of environmental electromagnetic (EM) field interactions in tissues have contributed to a new understanding of both normal growth and the biology of cancer in cell growth. From cancer research comes a floodtide of new knowledge about the disruption of communication by cancer-promoting chemicals with an onset of unregulated growth. Bioelectromagnetic research reveals clear evidence of joint actions at cell membranes of chemical cancer promoters and environmental electromagnetic fields. The union of these two disciplines has resulted in the first major new approach to tumor formation in 75 years, directing attention to dysfunctions in inward and outward streams of signals at cell membranes, rather than to damage DNA in cell nuclei, and to synergic actions of chemical pollutants and environmental electromagnetic fields. We are witnesses and, in great measure, participants in one of the great revolutions in the history of biology. In little more than a century, we have moved from organs, to tissues, to cells, and finally to the molecules that are the elegant fabric of living tissues. Today, we stand at a new frontier. It may be more difficult to comprehend, but it is far more significant; for it is at the atomic level, rather than the molecular, that physical, rather than chemical, processes appear to shape the flow of signals that are at the essence of living matter. To pursue these problems in the environment and in the laboratory, our needs for further research with appropriate budgets are great.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2205491

Efficient particle-in-cell simulation of auroral plasma phenomena using a CUDA enabled graphics processing unit

NASA Astrophysics Data System (ADS)

Sewell, Stephen

This thesis introduces a software framework that effectively utilizes low-cost commercially available Graphic Processing Units (GPUs) to simulate complex scientific plasma phenomena that are modeled using the Particle-In-Cell (PIC) paradigm. The software framework that was developed conforms to the Compute Unified Device Architecture (CUDA), a standard for general purpose graphic processing that was introduced by NVIDIA Corporation. This framework has been verified for correctness and applied to advance the state of understanding of the electromagnetic aspects of the development of the Aurora Borealis and Aurora Australis. For each phase of the PIC methodology, this research has identified one or more methods to exploit the problem's natural parallelism and effectively map it for execution on the graphic processing unit and its host processor. The sources of overhead that can reduce the effectiveness of parallelization for each of these methods have also been identified. One of the novel aspects of this research was the utilization of particle sorting during the grid interpolation phase. The final representation resulted in simulations that executed about 38 times faster than simulations that were run on a single-core general-purpose processing system. The scalability of this framework to larger problem sizes and future generation systems has also been investigated.

US Army Research Laboratory power sources R and D programs

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

Christopher, H.A.; Gilman, S.; Hamlen, R.P.

1993-05-01

The development and application of new electronic technologies over the recent past has resulted in a major evolution of new electronic battlefield equipment. The need for lighter-weight and more cost effective power sources with higher power/energy density capability is critical to the successful development and deployment of these new, high performance battlefield devices. The current status and thrust of the Army Research Laboratory's (ARL's) battery and fuel cell R and D programs that support these new and emerging applications will be reviewed. Major technical barriers will be identified along with the corresponding proposed approaches to solving these anticipated problems.

Genes, cells, and biobanks: Yes, there’s still a consent problem

PubMed Central

Murdoch, Blake

2017-01-01

From a research perspective, the interest in biobanking continues to intensify. Governments and industry have invested heavily in biobanks, as exemplified by initiatives like the United Kingdom Biobank and United States' Precision Medicine Initiative. But despite this enthusiasm, many profound legal and ethical challenges remain unresolved. Indeed, there continues to be disagreements about how best to obtain consent and the degree and nature of control that research participants retain over donated samples and health information. Emerging social trends—including concerns about commercialization and perceived rights of continuing control (“biorights”)—seem likely to intensify these issues. PMID:28742850

Apparatus for electroplating particles of small dimension

DOEpatents

Yu, Conrad M.; Illige, John D.

1982-01-01

The thickness, uniformity, and surface smoothness requirements for surface coatings of glass microspheres for use as targets for laser fusion research are critical. Because of their minute size, the microspheres are difficult to manipulate and control in electroplating systems. The electroplating apparatus (10) of the present invention addresses these problems by providing a cathode cell (20) having a cell chamber (22), a cathode (23) and an anode (26) electrically isolated from each other and connected to an electrical power source (24). During the plating process, the cathode (23) is controllably vibrated along with solution pulse to maintain the particles in random free motion so as to attain the desired properties.

Space solar cell research - Problems and potential

NASA Technical Reports Server (NTRS)

Flood, Dennis J.

1986-01-01

The value of a passive, maintenance-free, renewable energy source was immediately recognized in the early days of the space program, and the silicon solar cell, despite its infancy, was quickly pressed into service. Efficiencies of those early space solar arrays were low, and lifetimes shorter than hoped for, but within a decade significant advances had been made in both areas. Better performance was achieved because of a variety of factors, ranging from improvements in silicon single crystal material, to better device designs, to a better understanding of the factors that affect the performance of a solar cell in space. Chief among the latter, particularly for the mid-to-high altitude (HEO) and geosynchronous (GEO) orbits, are the effects of the naturally occurring particulate radiation environment. Although not as broadly important to the photovoltaic community at large as increased efficiency, the topic of radiation damage is critically important to use of solar cells in space, and is a major component of the NASA research program in space photovoltaics. This paper will give a brief overview of some of the opportunities and challenges for space photovoltaic applications, and will discuss some of the current reseach directed at achieving high efficiency and controlling the effects of radiation damage in space solar cells.

Novel cell-biological ideas deducible from morphological observations on "dark" neurons revisited.

PubMed

Gallyas, Ferenc

2007-05-30

The origin, nature and fate of "dark" (dramatically shrunken and hyperbasophilic) neurons are century-old problems in both human and experimental neuropathology. Until a few years ago, hardly any cell-biological conclusion had been drawn from their histological investigation. On the basis of light and electron microscopic findings in animal experiments performed during the past few years, my research team has put forward novel ideas concerning 1. the nature of "dark" neurons (malfunction of an energy-storing gel-structure that is ubiquitously present in all intracellular spaces between the ultrastructural elements), 2. the mechanism of their formation (non-programmed initiation of a whole-cell phase-transition in this gel-structure), 3. their capability of recovery (programmed for some physiological purpose), 4. their death mode (neither necrotic nor apoptotic), and 5. their relationship with the apoptotic cell death (the gel structure in question is programmed for the morphological execution of ontogenetic apoptosis). Based on morphological observations, this paper revisits these ideas in order to bring them to the attention of researchers who are in a position to investigate their validity by means of experimental paradigms other than those used here.

Analysis of the reflective multibandgap solar cell concept

NASA Technical Reports Server (NTRS)

Stern, T. G.

1983-01-01

A new and unique approach to improving photovoltaic conversion efficiency, the reflective multiband gap solar cell concept, was examined. This concept uses back surface reflectors and light trapping with several physically separated cells of different bandgaps to make more effective use of energy from different portions of the solar spectrum. Preliminary tests performed under General Dynamics Independent Research and Development (IRAD) funding have demonstrated the capability for achieving in excess of 20% conversion efficiency with aluminum gallium arsenide and silicon. This study analyzed the ultimate potential for high conversion efficiency with 2, 3, 4, and 5 different bandgap materials, determined the appropriate bandgaps needed to achieve this optimized efficiency, and identified potential problems or constraints. The analysis indicated that an improvement in efficiency of better than 40% could be attained in this multibandgap approach, compared to a single bandgap converter under the same assumptions. Increased absorption loss on the back surface reflector was found to incur a minimal penalty on efficiency for two and three bandgap systems. Current models for bulk absorption losses in 3-5 materials were found to be inadequate for explaining laboratory observed transmission losses. Recommendations included the continued development of high bandgap back surface reflector cells and basic research on semiconductor absorption mechanisms.

[Development of studies on bioeffects of ultrasound-acupuncture therapy and its underlying mechanism].

PubMed

Yang, Yu-Hua; Zhang, Di; Sa, Zhe-Yan; Huang, Meng; Ding, Guang-Hong

2012-08-01

The so-called ultrasound acupuncture is a therapeutic approach for clinical problems and health care by applying the ultrasound energy to the acupoints of the human body directly or indirectly. It has been applied in clinic for about 30 years since 1980s. In the present paper, the authors review the development of both experimental and clinical researches in the past 30 years. Its clinical application includes allergic rhinitis, local pain, mastitis, angina pectoris of coronary heart disease, stroke, etc. Regarding the researches on the underlying mechanism of ultrasound and ultrasound acupuncture, the authors make a summary from 1) bioeffects (thermal and nonthermal effects) of ultrasound intervention; 2) cell lysis and nonlysis effects of ultrasound intervention; and 3) effects of ultrasound acupuncture on the degranulation of mast cells. Based on the idea that "inflammatory reaction caused by mast cell degranulation is one of the initial factors of acupuncture for inducing therapeutic effects", bioeffects including cellular changes, especially mast cell degranulation caused by ultrasound stimulation, are thought to be the main possible mechanisms underlying the favorable efficacy of ultrasound acupuncture intervention. However, the ultrasound metrology and the specific superiority of ultrasound acupuncture remain unknown up to now.

Immune cell functions in pancreatic cancer.

PubMed

Plate, J M; Harris, J E

2000-01-01

Pancreatic cancer kills nearly 29,000 people in the United States annually-as many people as are diagnosed with the disease. Chemotherapeutic treatment is ineffective in halting progression of the disease. Yet, specific immunity to pancreatic tumor cells in subjects with pancreatic cancer has been demonstrated repeatedly during the last 24 years. Attempts to expand and enhance tumor-specific immunity with biotherapy, however, have not met with success. The question remains, "Why can't specific immunity regulate pancreatic cancer growth?" The idea that tumor cells have evolved protective mechanisms against immunity was raised years ago and has recently been revisited by a number of research laboratories. In pancreatic cancer, soluble factors produced by and for the protection of the tumor environment have been detected and are often distributed to the victim's circulatory system where they may effect a more generalized immunosuppression. Yet the nature of these soluble factors remains controversial, since some also serve as tumor antigens that are recognized by the same T cells that may become inactivated by them. Unless the problem of tumor-derived immunosuppressive products is addressed directly through basic and translational research studies, successful biotherapeutic treatment for pancreatic cancer may not be forthcoming.

A Virtual Aluminum Reduction Cell

NASA Astrophysics Data System (ADS)

Zhang, Hongliang; Zhou, Chenn Q.; Wu, Bing; Li, Jie

2013-11-01

The most important component in the aluminum industry is the aluminum reduction cell; it has received considerable interests and resources to conduct research to improve its productivity and energy efficiency. The current study focused on the integration of numerical simulation data and virtual reality technology to create a scientifically and practically realistic virtual aluminum reduction cell by presenting complex cell structures and physical-chemical phenomena. The multiphysical field simulation models were first built and solved in ANSYS software (ANSYS Inc., Canonsburg, PA, USA). Then, the methodology of combining the simulation results with virtual reality was introduced, and a virtual aluminum reduction cell was created. The demonstration showed that a computer-based world could be created in which people who are not analysis experts can see the detailed cell structure in a context that they can understand easily. With the application of the virtual aluminum reduction cell, even people who are familiar with aluminum reduction cell operations can gain insights that make it possible to understand the root causes of observed problems and plan design changes in much less time.

Advances in fuel cell vehicle design

NASA Astrophysics Data System (ADS)

Bauman, Jennifer

Factors such as global warming, dwindling fossil fuel reserves, and energy security concerns combine to indicate that a replacement for the internal combustion engine (ICE) vehicle is needed. Fuel cell vehicles have the potential to address the problems surrounding the ICE vehicle without imposing any significant restrictions on vehicle performance, driving range, or refuelling time. Though there are currently some obstacles to overcome before attaining the widespread commercialization of fuel cell vehicles, such as improvements in fuel cell and battery durability, development of a hydrogen infrastructure, and reduction of high costs, the fundamental concept of the fuel cell vehicle is strong: it is efficient, emits zero harmful emissions, and the hydrogen fuel can be produced from various renewable sources. Therefore, research on fuel cell vehicle design is imperative in order to improve vehicle performance and durability, increase efficiency, and reduce costs. This thesis makes a number of key contributions to the advancement of fuel cell vehicle design within two main research areas: powertrain design and DC/DC converters. With regards to powertrain design, this research first analyzes various powertrain topologies and energy storage system types. Then, a novel fuel cell-battery-ultracapacitor topology is presented which shows reduced mass and cost, and increased efficiency, over other promising topologies found in the literature. A detailed vehicle simulator is created in MATLAB/Simulink in order to simulate and compare the novel topology with other fuel cell vehicle powertrain options. A parametric study is performed to optimize each powertrain and general conclusions for optimal topologies, as well as component types and sizes, for fuel cell vehicles are presented. Next, an analytical method to optimize the novel battery-ultracapacitor energy storage system based on maximizing efficiency, and minimizing cost and mass, is developed. This method can be applied to any system utilizing the novel battery-ultracapacitor energy storage system and is not limited in application to only fuel cell vehicles. With regards to DC/DC converters, it is important to design efficient and light-weight converters for use in fuel cell and other electric vehicles to improve overall vehicle fuel economy. Thus, this research presents a novel soft-switching method, the capacitor-switched regenerative snubber, for the high-power DC/DC boost converters commonly used in fuel cell vehicles. This circuit is shown to increase the efficiency and reduce the overall mass of the DC/DC boost converter.

The heterologous expression strategies of antimicrobial peptides in microbial systems.

PubMed

Deng, Ting; Ge, Haoran; He, Huahua; Liu, Yao; Zhai, Chao; Feng, Liang; Yi, Li

2017-12-01

Antimicrobial peptides (AMPs) consist of molecules acting on the defense systems of numerous organisms toward tumor and multiple pathogens, such as bacteria, fungi, viruses, and parasites. Compared to traditional antibiotics, AMPs are more stable and have lower propensity for developing resistance through functioning in the innate immune system, thus having important applications in the fields of medicine, food and so on. However, despite of their high economic values, the low yield and the cumbersome extraction process in AMPs production are problems that limit their industrial application and scientific research. To conquer these obstacles, optimized heterologous expression technologies were developed that could provide effective ways to increase the yield of AMPs. In this review, the research progress on heterologous expression of AMPs using Escherichia coli, Bacillus subtilis, Pichia pastoris and Saccharomyces cerevisiae as host cells was mainly summarized, which might guide the expression strategies of AMPs in these cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Infrared micro-spectroscopy of human tissue: principles and future promises.

PubMed

Diem, Max; Ergin, Ayşegül; Remiszewski, Stan; Mu, Xinying; Akalin, Ali; Raz, Dan

2016-06-23

This article summarizes the methods employed, and the progress achieved over the past two decades in applying vibrational (Raman and IR) micro-spectroscopy to problems of medical diagnostics and cellular biology. During this time, several research groups have verified the enormous information contained in vibrational spectra; in fact, information on protein, lipid and metabolic composition of cells and tissues can be deduced by decoding the observed vibrational spectra. This decoding process is aided by the availability of computer workstations and advanced algorithms for data analysis. Furthermore, commercial instrumentation for the fast collection of both Raman and infrared micro-spectral data has enabled the collection of images of cells and tissues based solely on vibrational spectroscopic data. The progress in the field has been manifested by a steady increase in the number and quality of publications submitted by established and new research groups in vibrational spectroscopy in the biological and biomedical arenas.

Bio-engineering inslulin-secreting cells from embryonic stem cells: a review of progress.

PubMed

Roche, E; Sepulcre, M P; Enseñat-Waser, R; Maestre, I; Reig, J A; Soria, B

2003-07-01

According to the Edmonton protocol, human islet transplantation can result in insulin independency for periods longer than 3 years. However, this therapy for type 1 diabetes is limited by the scarcity of cadaveric donors. Owing to the ability of embryonic stem cells to expand in vitro and differentiate into a variety of cell types, research has focused on ways to manipulate these cells to overcome this problem. It has been demonstrated that mouse embryonic stem cells can differentiate into insulin-containing cells, restoring normoglycaemia in diabetic mice. To this end, mouse embryonic stem cells were transfected with a DNA construct that provides resistance to neomycin under the control of the regulatory regions of the human insulin gene. However, this protocol has a very low efficiency, needing improvements for this technology to be transferred to human stem cells. Optimum protocols will be instrumental in the production of an unlimited source of cells that synthesise, store and release insulin in a physiological manner. The review focuses on the alternative source of tissue offered by embryonic stem cells for regenerative medicine in diabetes and some key points that should be considered in order for a definitive protocol for in vitro differentiation to be established.

A 3D finite element ALE method using an approximate Riemann solution

DOE PAGES

Chiravalle, V. P.; Morgan, N. R.

2016-08-09

Arbitrary Lagrangian–Eulerian finite volume methods that solve a multidimensional Riemann-like problem at the cell center in a staggered grid hydrodynamic (SGH) arrangement have been proposed. This research proposes a new 3D finite element arbitrary Lagrangian–Eulerian SGH method that incorporates a multidimensional Riemann-like problem. Here, two different Riemann jump relations are investigated. A new limiting method that greatly improves the accuracy of the SGH method on isentropic flows is investigated. A remap method that improves upon a well-known mesh relaxation and remapping technique in order to ensure total energy conservation during the remap is also presented. Numerical details and test problemmore » results are presented.« less

A 3D finite element ALE method using an approximate Riemann solution

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

Chiravalle, V. P.; Morgan, N. R.

Arbitrary Lagrangian–Eulerian finite volume methods that solve a multidimensional Riemann-like problem at the cell center in a staggered grid hydrodynamic (SGH) arrangement have been proposed. This research proposes a new 3D finite element arbitrary Lagrangian–Eulerian SGH method that incorporates a multidimensional Riemann-like problem. Here, two different Riemann jump relations are investigated. A new limiting method that greatly improves the accuracy of the SGH method on isentropic flows is investigated. A remap method that improves upon a well-known mesh relaxation and remapping technique in order to ensure total energy conservation during the remap is also presented. Numerical details and test problemmore » results are presented.« less

Classical dense matter physics: some basic methods and results

NASA Astrophysics Data System (ADS)

Čelebonović, Vladan

2002-07-01

This is an introduction to the basic notions, some methods and open problems of dense matter physics and their applications in astrophysics. Experimental topics cover the range from the work of P. W. Bridgman to the discovery and basic results of use of the diamond anvil cell. On the theoretical side, the semiclassical method of P. Savić and R. Kašanin is described. The choice of these topics is conditioned by their applicability in astrophysics and the author's research experience. At the end of the paper is presented a list of some unsolved problems in dense matter physics and astrophysics, some (or all) of which could form a basis of future collaborations.

Optimal control for Malaria disease through vaccination

NASA Astrophysics Data System (ADS)

Munzir, Said; Nasir, Muhammad; Ramli, Marwan

2018-01-01

Malaria is a disease caused by an amoeba (single-celled animal) type of plasmodium where anopheles mosquito serves as the carrier. This study examines the optimal control problem of malaria disease spread based on Aron and May (1982) SIR type models and seeks the optimal solution by minimizing the prevention of the spreading of malaria by vaccine. The aim is to investigate optimal control strategies on preventing the spread of malaria by vaccination. The problem in this research is solved using analytical approach. The analytical method uses the Pontryagin Minimum Principle with the symbolic help of MATLAB software to obtain optimal control result and to analyse the spread of malaria with vaccination control.

Air Force electrochemical power research and technology program for space applications

NASA Technical Reports Server (NTRS)

Allen, Douglas

1987-01-01

An overview is presented of the existing Air Force electrochemical power, battery, and fuel cell programs for space application. Present thrusts are described along with anticipated technology availability dates. Critical problems to be solved before system applications occur are highlighted. Areas of needed performance improvement of batteries and fuel cells presently used are outlined including target dates for key demonstrations of advanced technology. Anticipated performance and current schedules for present technology programs are reviewed. Programs that support conventional military satellite power systems and special high power applications are reviewed. Battery types include bipolar lead-acid, nickel-cadmium, silver-zinc, nickel-hydrogen, sodium-sulfur, and some candidate advanced couples. Fuel cells for pulsed and transportation power applications are discussed as are some candidate advanced regenerative concepts.

Degradable Organically-Derivatized Polyoxometalate with Enhanced Activity against Glioblastoma Cell Line

NASA Astrophysics Data System (ADS)

She, Shan; Bian, Shengtai; Huo, Ruichao; Chen, Kun; Huang, Zehuan; Zhang, Jiangwei; Hao, Jian; Wei, Yongge

2016-09-01

High efficacy and low toxicity are critical for cancer treatment. Polyoxometalates (POMs) have been reported as potential candidates for cancer therapy. On accounts of the slow clearance of POMs, leading to long-term toxicity, the clinical application of POMs in cancer treatment is restricted. To address this problem, a degradable organoimido derivative of hexamolybdate is developed by modifying it with a cleavable organic group, leading to its degradation. Of note, this derivative exhibits favourable pharmacodynamics towards human malignant glioma cell (U251), the ability to penetrate across blood brain barrier and low toxicity towards rat pheochromocytoma cell (PC12). This line of research develops an effective POM-based agent for glioblastoma inhibition and will pave a new way to construct degradable anticancer agents for clinical cancer therapy.

Quorum sensing and microbial drug resistance.

PubMed

Chen, Yu-fan; Liu, Shi-yin; Liang, Zhi-bin; Lv, Ming-fa; Zhou, Jia-nuan; Zhang, Lian-hui

2016-10-20

Microbial drug resistance has become a serious problem of global concern, and the evolution and regulatory mechanisms of microbial drug resistance has become a hotspot of research in recent years. Recent studies showed that certain microbial resistance mechanisms are regulated by quorum sensing system. Quorum sensing is a ubiquitous cell-cell communication system in the microbial world, which associates with cell density. High-density microbial cells produce sufficient amount of small signal molecules, activating a range of downstream cellular processes including virulence and drug resistance mechanisms, which increases bacterial drug tolerance and causes infections on host organisms. In this review, the general mechanisms of microbial drug resistance and quorum-sensing systems are summarized with a focus on the association of quorum sensing and chemical signaling systems with microbial drug resistance mechanisms, including biofilm formation and drug efflux pump. The potential use of quorum quenching as a new strategy to control microbial resistance is also discussed.

The role of the cell wall in fungal pathogenesis

PubMed Central

Arana, David M.; Prieto, Daniel; Román, Elvira; Nombela, César; Alonso‐Monge, Rebeca; Pla, Jesús

2009-01-01

Summary Fungal infections are a serious health problem. In recent years, basic research is focusing on the identification of fungal virulence factors as promising targets for the development of novel antifungals. The wall, as the most external cellular component, plays a crucial role in the interaction with host cells mediating processes such as adhesion or phagocytosis that are essential during infection. Specific components of the cell wall (called PAMPs) interact with specific receptors in the immune cell (called PRRs), triggering responses whose molecular mechanisms are being elucidated. We review here the main structural carbohydrate components of the fungal wall (glucan, mannan and chitin), how their biogenesis takes place in fungi and the specific receptors that they interact with. Different model fungal pathogens are chosen to illustrate the functional consequences of this interaction. Finally, the identification of the key components will have important consequences in the future and will allow better approaches to treat fungal infections. PMID:21261926

Air pollution effects on the guard cells of the injury resistant leaf of Laurus nobilis L

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

Christodoulakis, N.S.

1993-09-01

The need for cleaner air has led to detailed investigations not only on the sources and types of air pollutants but also on the effect that these compounds have on various life forms. The plants are the first [open quotes]victims[close quotes] of the air pollutants. Extensive literature exists on the structural damages and functional problems that plants suffer after being exposed to air pollutants. Many investigators prefer to deal with damages, caused to various organs, in plants growing in non polluted environments, after being fumigated with certain air pollutants. Others investigate the problems in plants growing in polluted areas thusmore » being subject to long-term exposure to air pollutants. Generally it seems that primary producers suffer injuries, most of the time serious, that finally lead to the suppression of photosynthesis with all the undesirable consequences that this situation has for the ecosystem. Unfortunately Athens is not only the most polluted city in Greece but also an example to be avoided among the most polluted cities in the world. Serious problems occur in plants living in this environment. One exception is Laurus nobilis, introduced as an injury resistant species. These researchers studied the plant cells and the structure of their organelles, focusing on the guard cells of the leaves. They occur on the underside of leaves and they are directly affected by polluted air. Studies show that the air pollution injury resistance of Laurus is genetic. 25 refs., 21 figs« less

A Novel Fluorescence-Labeled Curcumin Conjugate: Synthesis, Evaluation And Imaging On Human Cell Lines.

PubMed

Sheikh, Sumbla; Sturzu, Alexander; Kalbacher, Hubert; Nagele, Thomas; Weidenmaier, Christopher; Horger, Marius; Schwentner, Christian; Ernemann, Ulrike; Heckl, Stefan

2018-04-05

Curcumin, as the main ingredient of the curcuma spice has increasingly become the target of scientific research. The turmeric root which the spice is obtained from has been widely used in traditional medicine and scientific studies found anti-inflammatory, anti-cancer, anti-angiogenic effects as well as antibacterial properties for curcumin. Recently, curcumin has gathered interest as potential therapeutic agent in the research on Alzheimer's disease. A consistent problem in the investigative and therapeutic applications of curcumin is its poor solubility in aqueous solutions. In the present study we synthesized a conjugate of curcumin, the amino acid lysine and the fluorescent dye fluorescein. This conjugate was soluble in cell culture medium and facilitated the examination of curcumin with fluorescence imaging methods. We studied the cell growth impact of unmodified curcumin on seven different human cell lines and then analyzed the uptake and cellular localization of our curcumin conjugate with confocal laser scanning imaging and flow cytometry on the seven cell lines. We found that unbound curcumin inhibited cell growth in vitro and was not taken up into the cells. The curcumin conjugate was internalized into the cell cytoplasm in a dot-like pattern and cellular uptake correlated with cell membrane damage which was measured using propidium iodide. The CAL-72 osteosarcoma cell exhibited 3-4fold increased conjugate uptake and a strong uniform fluorescein staining in addition to the dot-like pattern observed in all cell lines. In conclusion we successfully synthesized a novel water-soluble fluorescent curcumin conjugate which showed a strong preference for CAL-72 osteosarcoma cells in vitro. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Mucosal-associated invariant T cells from induced pluripotent stem cells: A novel approach for modeling human diseases

PubMed Central

Sugimoto, Chie; Fujita, Hiroyoshi; Wakao, Hiroshi

2016-01-01

Mice have frequently been used to model human diseases involving immune dysregulation such as autoimmune and inflammatory diseases. These models help elucidate the mechanisms underlying the disease and in the development of novel therapies. However, if mice are deficient in certain cells and/or effectors associated with human diseases, how can their functions be investigated in this species? Mucosal-associated invariant T (MAIT) cells, a novel innate-like T cell family member, are a good example. MAIT cells are abundant in humans but scarce in laboratory mice. MAIT cells harbor an invariant T cell receptor and recognize nonpeptidic antigens vitamin B2 metabolites from bacteria and yeasts. Recent studies have shown that MAIT cells play a pivotal role in human diseases such as bacterial infections and autoimmune and inflammatory diseases. MAIT cells possess granulysin, a human-specific effector molecule, but granulysin and its homologue are absent in mice. Furthermore, MAIT cells show poor proliferation in vitro. To overcome these problems and further our knowledge of MAIT cells, we have established a method to expand MAIT cells via induced pluripotent stem cells (iPSCs). In this review, we describe recent advances in the field of MAIT cell research and our approach for human disease modeling with iPSC-derived MAIT cells. PMID:27114747

NASA flight cell and battery issues

NASA Technical Reports Server (NTRS)

Schulze, N. R.

1989-01-01

The author presents the important battery and cell problems, encompassing both test failures and accidents, which were encountered during the past year. Practical issues facing programs, which have to be considered in the development of a battery program strategy, are addressed. The problems of one program, the GRO (Gamma Ray Observatory), during the past year are focused on to illustrate the fundamental types of battery problems that occur. Problems encountered by other programs are briefly mentioned to complete the accounting. Two major categories of issues are defined, namely, whose which are quality and design related, i.e., problems having inherent manufacturing-process-related aspects with an impact on cell reliability, and these which are accident triggered or man induced, i.e., those operational issues having an impact on battery and cell reliability.

Exploiting Bounded Signal Flow for Graph Orientation Based on Cause-Effect Pairs

NASA Astrophysics Data System (ADS)

Dorn, Britta; Hüffner, Falk; Krüger, Dominikus; Niedermeier, Rolf; Uhlmann, Johannes

We consider the following problem: Given an undirected network and a set of sender-receiver pairs, direct all edges such that the maximum number of "signal flows" defined by the pairs can be routed respecting edge directions. This problem has applications in communication networks and in understanding protein interaction based cell regulation mechanisms. Since this problem is NP-hard, research so far concentrated on polynomial-time approximation algorithms and tractable special cases. We take the viewpoint of parameterized algorithmics and examine several parameters related to the maximum signal flow over vertices or edges. We provide several fixed-parameter tractability results, and in one case a sharp complexity dichotomy between a linear-time solvable case and a slightly more general NP-hard case. We examine the value of these parameters for several real-world network instances. For many relevant cases, the NP-hard problem can be solved to optimality. In this way, parameterized analysis yields both deeper insight into the computational complexity and practical solving strategies.

Revisiting the mitogenetic effect of ultra-weak photon emission

PubMed Central

Volodyaev, Ilya; Beloussov, Lev V.

2015-01-01

This paper reviews the 90 years long controversial history of the so-called “mitogenetic radiation,” the first case of non-chemical distant interactions, reported by Gurwitsch (1923). It was soon described as ultraweak UV, emitted by a number of biological systems, and stimulating mitosis in “competent” (in this sense) cells. In the following 20 years this phenomenon attracted enormous interest of the scientific community, and gave rise to more than 700 publications around the world. Yet, this wave of research vanished after several ostensibly disproving works in late 1930-s, and was not resumed later, regardless of quite serious grounds for that. The authors discuss separately two aspects of the problem: (1) do living organisms emit ultraweak radiation in the UV range (irrespective of whether it has any biological role), and (2) are there any real effects of this ultraweak photon emission (UPE) upon cell division and/or other biological functions? Analysis of the available data permits to conclude, that UV fraction of UPE should be regarded real, while its biological effects are difficult to reproduce. This causes a paradox. A number of presently known qualities of UPE were initially discovered (predicted?) by the “early workers” on the basis of biological effects. Yet the qualities they discovered were proved later (the UV component of UPE, the sources of UPE among biological systems, etc…), while the biological effect they used for UPE “detection” remains questionable. Importance of this area for basic biology and medicine, and potential usefulness of UPE as a non-invasive research method, invite scientists to attack this problem again, applying powerful research facilities of modern science. Yet, because of complexity and uncertainty of the problem, further progress in this area demands comprehensive examination of both positive and negative works, with particular attention to their methodical details. PMID:26441668

Use of a fiber glass optical system to measure the contractile characteristics of a single isolated muscle cell

NASA Astrophysics Data System (ADS)

Chen, Chulung; Yin, Shizhuo; Li, Jiang; Yu, Francis T. S.; Cheung, Joseph Y.; Zhang, Xueqian; Lei, Xiaoxiao; Wu, Zhongkong

1998-05-01

Cell is the basic structural and fundamental unit of all organisms; the smallest structure capable of performing all the activities vital to life. One goal of current research interest is to learn how the muscle varies the strength of its contraction in response to electric stimuli. A wide variety of techniques have been developed to monitor the mechanical response of isolated cardiac myocytes. Some success has been reported either with the use of intact rat myocytes supported by suction micropipettes or in guinea pig myocytes adhering to glass beams. However, the usual measuring techniques exhibit destructive contact performance on live cells. They could not solve the problem, since the cell may die during or after the time-consuming attachment process at the beginning of each experiment. In contrast, a novel optical system, which consists of a microglass tube with an inner diameter the same size of a real cardiac cell, is proposed to simulate real cell's twitch process. the physical parameters of synthetic cell are well known. By comparing the dynamics of the real cell with that of the simulated cell, the twitch characteristics of the real cell can be measured.

Prevalence of problematic cell phone use in an adult population in Spain as assessed by the Mobile Phone Problem Use Scale (MPPUS).

PubMed

de-Sola, José; Talledo, Hernán; Rodríguez de Fonseca, Fernando; Rubio, Gabriel

2017-01-01

Problematic cell phone use has alarmingly increased in industrialized countries in the past 10 years. For many perpetrators, it can turn into a behavioural addiction, although this is not a recognized medical condition. Although there are many tools for evaluating this use, one of the most widely used tools is the Mobile Phone Problematic Use Scale (MPPUS), which we test on a representative sample of the population in Spain to obtain an estimate of the prevalence of problematic cell phone use in our midst. The age range consists of 16-65 years, with 1,126 surveys conducted. In this population, we verify that the reliability and internal consistency of the MPPUS (α = 0.939) are maintained. Additionally, the construct validity, considering the derived factors (Abuse and Dependence, Craving and Loss of Control, and Dependence on the Social Environment) are aligned with other research and with diverse external criteria of addiction. We establish four categories of users (Casual, Regular, At Risk, and Problematic) and obtain a prevalence of 15.4% among At Risk Users and 5.1% among Problematic Users. This finding implies a total of 20.5% of Users with Problems. A binary logistic regression analysis shows that age, gender, level of education, and daily cell phone use predict problematic cell phone use. The results, based on multiple criteria, show that such problematic use shares features of recognized addictions, affecting large segments of the population and not only adolescents.

Research on Life Science and Life Support Engineering Problems of Manned Deep Space Exploration Mission

NASA Astrophysics Data System (ADS)

Qi, Bin; Guo, Linli; Zhang, Zhixian

2016-07-01

Space life science and life support engineering are prominent problems in manned deep space exploration mission. Some typical problems are discussed in this paper, including long-term life support problem, physiological effect and defense of varying extraterrestrial environment. The causes of these problems are developed for these problems. To solve these problems, research on space life science and space medical-engineering should be conducted. In the aspect of space life science, the study of space gravity biology should focus on character of physiological effect in long term zero gravity, co-regulation of physiological systems, impact on stem cells in space, etc. The study of space radiation biology should focus on target effect and non-target effect of radiation, carcinogenicity of radiation, spread of radiation damage in life system, etc. The study of basic biology of space life support system should focus on theoretical basis and simulating mode of constructing the life support system, filtration and combination of species, regulation and optimization method of life support system, etc. In the aspect of space medical-engineering, the study of bio-regenerative life support technology should focus on plants cultivation technology, animal-protein production technology, waste treatment technology, etc. The study of varying gravity defense technology should focus on biological and medical measures to defend varying gravity effect, generation and evaluation of artificial gravity, etc. The study of extraterrestrial environment defense technology should focus on risk evaluation of radiation, monitoring and defending of radiation, compound prevention and removal technology of dust, etc. At last, a case of manned lunar base is analyzed, in which the effective schemes of life support system, defense of varying gravity, defense of extraterrestrial environment are advanced respectively. The points in this paper can be used as references for intensive study on key technologies.

Short tandem repeat DNA typing provides an international reference standard for authentication of human cell lines.

PubMed

Dirks, Wilhelm Gerhard; Faehnrich, Silke; Estella, Isabelle Annick Janine; Drexler, Hans Guenter

2005-01-01

Cell lines have wide applications as model systems in the medical and pharmaceutical industry. Much drug and chemical testing is now first carried out exhaustively on in vitro systems, reducing the need for complicated and invasive animal experiments. The basis for any research, development or production program involving cell lines is the choice of an authentic cell line. Microsatellites in the human genome that harbour short tandem repeat (STR) DNA markers allow individualisation of established cell lines at the DNA level. Fluorescence polymerase chain reaction amplification of eight highly polymorphic microsatellite STR loci plus gender determination was found to be the best tool to screen the uniqueness of DNA profiles in a fingerprint database. Our results demonstrate that cross-contamination and misidentification remain chronic problems in the use of human continuous cell lines. The combination of rapidly generated DNA types based on single-locus STR and their authentication or individualisation by screening the fingerprint database constitutes a highly reliable and robust method for the identification and verification of cell lines.

Cytoprotective Effect of Epigallocatechin Gallate (EGCG)-5'-O-α-Glucopyranoside, a Novel EGCG Derivative.

PubMed

Han, Sang Yun; Kim, Eunji; Hwang, Kyeonghwan; Ratan, Zubair Ahmed; Hwang, Hyunsik; Kim, Eun-Mi; Kim, Doman; Park, Junseong; Cho, Jae Youl

2018-05-15

Epigallocatechin gallate (EGCG) is a well-studied polyphenol with antioxidant effects. Since EGCG has low solubility and stability, many researchers have modified EGCG residues to ameliorate these problems. A novel EGCG derivative, EGCG-5'- O -α-glucopyranoside (EGCG-5'Glu), was synthesized, and its characteristics were investigated. EGCG-5'Glu showed antioxidant effects in cell and cell-free systems. Under SNP-derived radical exposure, EGCG-5'Glu decreased nitric oxide (NO) production, and recovered ROS-mediated cell viability. Moreover, EGCG-5'Glu regulated apoptotic pathways (caspases) and cell survival molecules (phosphoinositide 3-kinase (PI3K) and phosphoinositide-dependent kinase 1 (PDK1)). In another radical-induced condition, ultraviolet B (UVB) irradiation, EGCG-5'Glu protected cells from UVB and regulated the PI3K/PDK1/AKT pathway. Next, the proliferative effect of EGCG-5'Glu was examined. EGCG-5'Glu increased cell proliferation by modulating nuclear factor (NF)-κB activity. EGCG-5'Glu protects and repairs cells from external damage via its antioxidant effects. These results suggest that EGCG-5'Glu could be used as a cosmetics ingredient or dietary supplement.

Stem cell research and transplantation: science leading ethics.

PubMed

Daar, A S; Bhatt, A; Court, E; Singer, P A

2004-10-01

One of the most exciting developments in the biological sciences in the past decade has been the discovery and characterization of human embryonic stem cells (ESCs). The interest to transplanters is the potential applications of stem cells in regenerative medicine (RM), which may involve tissue engineering, genetic engineering, and other techniques to repair, replace, or regenerate failing tissues and organs. There is little controversy surrounding human adult stem cells. However, human ESCs are surrounded by a number of ethical controversies, the extent of which is partly dependent on their source. Those derived from currently existing embryonic stem cell lines are less controversial than those derived from "excess" embryos from in vitro fertilization (IVF) clinics, while ESCs derived from IVF embryos specifically created for the purpose are not acceptable to many people arguing from religious and other moral perspectives. Somatic cell nuclear transfer, or therapeutic cloning, must be distinguished from reproductive cloning. It holds the most promise for regenerative medicine. ESCs can also be derived from gonadal ridges of aborted fetuses. The transplant community must strive to uphold societal values in its effort to find remedies for their ailing patients and address the perennial problem of organ shortage. Transplanters also have a responsibility to engage the public in their efforts to gain public understanding and support, and policy makers must take into account public opinion. Only in this way can we realize the great potential of stem cell research for organ transplantation.

Constraint Programming to Solve Maximal Density Still Life

NASA Astrophysics Data System (ADS)

Chu, Geoffrey; Petrie, Karen Elizabeth; Yorke-Smith, Neil

The Maximum Density Still Life problem fills a finite Game of Life board with a stable pattern of cells that has as many live cells as possible. Although simple to state, this problem is computationally challenging for any but the smallest sizes of board. Especially difficult is to prove that the maximum number of live cells has been found. Various approaches have been employed. The most successful are approaches based on Constraint Programming (CP). We describe the Maximum Density Still Life problem, introduce the concept of constraint programming, give an overview on how the problem can be modelled and solved with CP, and report on best-known results for the problem.

Harnessing biomechanics to develop cartilage regeneration strategies.

PubMed

Athanasiou, Kyriacos A; Responte, Donald J; Brown, Wendy E; Hu, Jerry C

2015-02-01

As this review was prepared specifically for the American Society of Mechanical Engineers H.R. Lissner Medal, it primarily discusses work toward cartilage regeneration performed in Dr. Kyriacos A. Athanasiou's laboratory over the past 25 years. The prevalence and severity of degeneration of articular cartilage, a tissue whose main function is largely biomechanical, have motivated the development of cartilage tissue engineering approaches informed by biomechanics. This article provides a review of important steps toward regeneration of articular cartilage with suitable biomechanical properties. As a first step, biomechanical and biochemical characterization studies at the tissue level were used to provide design criteria for engineering neotissues. Extending this work to the single cell and subcellular levels has helped to develop biochemical and mechanical stimuli for tissue engineering studies. This strong mechanobiological foundation guided studies on regenerating hyaline articular cartilage, the knee meniscus, and temporomandibular joint (TMJ) fibrocartilage. Initial tissue engineering efforts centered on developing biodegradable scaffolds for cartilage regeneration. After many years of studying scaffold-based cartilage engineering, scaffoldless approaches were developed to address deficiencies of scaffold-based systems, resulting in the self-assembling process. This process was further improved by employing exogenous stimuli, such as hydrostatic pressure, growth factors, and matrix-modifying and catabolic agents, both singly and in synergistic combination to enhance neocartilage functional properties. Due to the high cell needs for tissue engineering and the limited supply of native articular chondrocytes, costochondral cells are emerging as a suitable cell source. Looking forward, additional cell sources are investigated to render these technologies more translatable. For example, dermis isolated adult stem (DIAS) cells show potential as a source of chondrogenic cells. The challenging problem of enhanced integration of engineered cartilage with native cartilage is approached with both familiar and novel methods, such as lysyl oxidase (LOX). These diverse tissue engineering strategies all aim to build upon thorough biomechanical characterizations to produce functional neotissue that ultimately will help combat the pressing problem of cartilage degeneration. As our prior research is reviewed, we look to establish new pathways to comprehensively and effectively address the complex problems of musculoskeletal cartilage regeneration.

The Factors Affecting Definition of Research Problems in Educational Technology Researches

ERIC Educational Resources Information Center

Bahçekapili, Ekrem; Bahçekapili, Tugba; Fis Erümit, Semra; Göktas, Yüksel; Sözbilir, Mustafa

2013-01-01

Research problems in a scientific research are formed after a certain process. This process starts with defining a research topic and transforms into a specific research problem or hypothesis. The aim of this study was to examine the way educational technology researchers identify their research problems. To this end, sources that educational…

Estimating Rates of Psychosocial Problems in Urban and Poor Children with Sickle Cell Anemia.

ERIC Educational Resources Information Center

Barbarin, Oscar A.; And Others

1994-01-01

Examined adjustment problems for children and adolescents with sickle cell anemia (SCA). Parents provided information on social, emotional, academic, and family adjustment of 327 children with SCA. Over 25% of children had emotional adjustment problems in form of internalizing symptoms (anxiety and depression); at least 20% had problems related to…

Methods and analysis of factors impact on the efficiency of the photovoltaic generation

NASA Astrophysics Data System (ADS)

Tianze, Li; Xia, Zhang; Chuan, Jiang; Luan, Hou

2011-02-01

First of all, the thesis elaborates two important breakthroughs which happened In the field of the application of solar energy in the 1950s.The 21st century the development of solar photovoltaic power generation will have the following characteristics: the continued high growth of industrial development, the significantly reducing cost of the solar cell, the large-scale high-tech development of photovoltaic industries, the breakthroughs of the film battery technology, the rapid development of solar PV buildings integration and combined to the grids. The paper makes principles of solar cells the theoretical analysis. On the basis, we study the conversion efficiency of solar cells, find the factors impact on the efficiency of the photovoltaic generation, solve solar cell conversion efficiency of technical problems through the development of new technology, and open up new ways to improve the solar cell conversion efficiency. Finally, the paper connecting with the practice establishes policies and legislation to the use of encourage renewable energy, development strategy, basic applied research etc.

Stem Cells as a Tool to Improve Outcomes of Islet Transplantation

PubMed Central

Sims, Emily; Evans-Molina, Carmella

2012-01-01

The publication of the promising results of the Edmonton protocol in 2000 generated optimism for islet transplantation as a potential cure for Type 1 Diabetes Mellitus. Unfortunately, follow-up data revealed that less than 10% of patients achieved long-term insulin independence. More recent data from other large trials like the Collaborative Islet Transplant Registry show incremental improvement with 44% of islet transplant recipients maintaining insulin independence at three years of follow-up. Multiple underlying issues have been identified that contribute to islet graft failure, and newer research has attempted to address these problems. Stem cells have been utilized not only as a functional replacement for β cells, but also as companion or supportive cells to address a variety of different obstacles that prevent ideal graft viability and function. In this paper, we outline the manners in which stem cells have been applied to address barriers to the achievement of long-term insulin independence following islet transplantation. PMID:22970344

Biomimetic materials for controlling bone cell responses.

PubMed

Drevelle, Olivier; Faucheux, Nathalie

2013-01-01

Bone defects that cannot "heal spontaneously during life" will become an ever greater health problem as populations age. Harvesting autografts has several drawbacks, such as pain and morbidity at both donor and acceptor sites, the limited quantity of material available, and frequently its inappropriate shape. Researchers have therefore developed alternative strategies that involve biomaterials to fill bone defects. These biomaterials must be biocompatible and interact with the surrounding bone tissue to allow their colonization by bone cells and blood vessels. The latest generation biomaterials are not inert; they control cell responses like adhesion, proliferation and differentiation. These biomaterials are called biomimetic materials. This review focuses on the development of third generation materials. We first briefly describe the bone tissue with its cells and matrix, and then how bone cells interact with the extracellular matrix. The next section covers the materials currently used to repair bone defects. Finally, we describe the strategies employed to modify the surface of materials, such as coating with hydroxyapatite and grafting biomolecules.

The perpetual movements of anaphase.

PubMed

Maiato, Helder; Lince-Faria, Mariana

2010-07-01

One of the most extraordinary events in the lifetime of a cell is the coordinated separation of sister chromatids during cell division. This is truly the essence of the entire mitotic process and the reason for the most profound morphological changes in cytoskeleton and nuclear organization that a cell may ever experience. It all occurs within a very short time window known as "anaphase", as if the cell had spent the rest of its existence getting ready for this moment in an ultimate act of survival. And there is a good reason for this: no space for mistakes. Problems in the distribution of chromosomes during cell division have been correlated with aneuploidy, a common feature observed in cancers and several birth defects, and the main cause of spontaneous abortion in humans. In this paper, we critically review the mechanisms of anaphase chromosome motion that resisted the scrutiny of more than 100 years of research, as part of a tribute to the pioneering work of Miguel Mota.

The unregulated commercialization of stem cell treatments: a global perspective.

PubMed

Sipp, Douglas

2011-12-01

Research into the biological properties and clinical potential of stem cells has spurred strong public investment, industry development, media coverage, and patient interest in recent years. To date, however, few clinical applications of demonstrated safety and efficacy have been developed with the exception of uses of hematopoietic stem cells in the treatment of diseases of the blood and immune systems. This lack of an evidence basis notwithstanding, hundreds of companies and private clinics around the world now sell putative stem cell treatments for an enormously broad range of medical and quality-of-life conditions. This represents a major challenge for legitimate scientists working in the field, for authorities seeking to protect their constituencies, and for patients and consumers targeted by such companies' marketing strategies. In this review, I provide an overview of the global industry in pseudomedical stem cell treatments, with an investigation of claims in a single disease area (amyotrophic lateral sclerosis), and make recommendations for the introduction and enforcement of appropriate regulatory responses to this problem.

Rethinking cell-cycle-dependent gene expression in Schizosaccharomyces pombe.

PubMed

Cooper, Stephen

2017-11-01

Three studies of gene expression during the division cycle of Schizosaccharomyces pombe led to the proposal that a large number of genes are expressed at particular times during the S. pombe cell cycle. Yet only a small fraction of genes proposed to be expressed in a cell-cycle-dependent manner are reproducible in all three published studies. In addition to reproducibility problems, questions about expression amplitudes, cell-cycle timing of expression, synchronization artifacts, and the problem with methods for synchronizing cells must be considered. These problems and complications prompt the idea that caution should be used before accepting the conclusion that there are a large number of genes expressed in a cell-cycle-dependent manner in S. pombe.

A Transparent Window into Biology: A Primer on Caenorhabditis elegans.

PubMed

Corsi, Ann K; Wightman, Bruce; Chalfie, Martin

2015-06-01

A little over 50 years ago, Sydney Brenner had the foresight to develop the nematode (round worm) Caenorhabditis elegans as a genetic model for understanding questions of developmental biology and neurobiology. Over time, research on C. elegans has expanded to explore a wealth of diverse areas in modern biology including studies of the basic functions and interactions of eukaryotic cells, host-parasite interactions, and evolution. C. elegans has also become an important organism in which to study processes that go awry in human diseases. This primer introduces the organism and the many features that make it an outstanding experimental system, including its small size, rapid life cycle, transparency, and well-annotated genome. We survey the basic anatomical features, common technical approaches, and important discoveries in C. elegans research. Key to studying C. elegans has been the ability to address biological problems genetically, using both forward and reverse genetics, both at the level of the entire organism and at the level of the single, identified cell. These possibilities make C. elegans useful not only in research laboratories, but also in the classroom where it can be used to excite students who actually can see what is happening inside live cells and tissues. Copyright © 2015 Corsi, Wightman, and Chalfie.

The SIMRAND methodology - Simulation of Research and Development Projects

NASA Technical Reports Server (NTRS)

Miles, R. F., Jr.

1984-01-01

In research and development projects, a commonly occurring management decision is concerned with the optimum allocation of resources to achieve the project goals. Because of resource constraints, management has to make a decision regarding the set of proposed systems or tasks which should be undertaken. SIMRAND (Simulation of Research and Development Projects) is a methodology which was developed for aiding management in this decision. Attention is given to a problem description, aspects of model formulation, the reduction phase of the model solution, the simulation phase, and the evaluation phase. The implementation of the considered approach is illustrated with the aid of an example which involves a simplified network of the type used to determine the price of silicon solar cells.

Determination system for solar cell layout in traffic light network using dominating set

NASA Astrophysics Data System (ADS)

Eka Yulia Retnani, Windi; Fambudi, Brelyanes Z.; Slamin

2018-04-01

Graph Theory is one of the fields in Mathematics that solves discrete problems. In daily life, the applications of Graph Theory are used to solve various problems. One of the topics in the Graph Theory that is used to solve the problem is the dominating set. The concept of dominating set is used, for example, to locate some objects systematically. In this study, the dominating set are used to determine the dominating points for solar panels, where the vertex represents the traffic light point and the edge represents the connection between the points of the traffic light. To search the dominating points for solar panels using the greedy algorithm. This algorithm is used to determine the location of solar panel. This research produced applications that can determine the location of solar panels with optimal results, that is, the minimum dominating points.

The Role of Functional Foods, Nutraceuticals, and Food Supplements in Intestinal Health

PubMed Central

Cencic, Avrelija; Chingwaru, Walter

2010-01-01

New eating habits, actual trends in production and consumption have a health, environmental and social impact. The European Union is fighting diseases characteristic of a modern age, such as obesity, osteoporosis, cancer, diabetes, allergies and dental problems. Developed countries are also faced with problems relating to aging populations, high energy foods, and unbalanced diets. The potential of nutraceuticals/functional foods/food supplements in mitigating health problems, especially in the gastrointestinal (GI) tract, is discussed. Certain members of gut microflora (e.g., probiotic/protective strains) play a role in the host health due to its involvement in nutritional, immunologic and physiological functions. The potential mechanisms by which nutraceuticals/functional foods/food supplements may alter a host’s health are also highlighted in this paper. The establishment of novel functional cell models of the GI and analytical tools that allow tests in controlled experiments are highly desired for gut research. PMID:22254045

Sickle Cell Screening: Medical, Legal, Ethical, Psychological and Social Problems; A Sickle Cell Crisis.

ERIC Educational Resources Information Center

Bowman, James E.

In recent years, sickle cell screening programs have been initiated by community groups, health centers, hospitals, medical schools, health departments, school systems, city and State governments, various branches of the Federal Government, fraternal and social clubs, and other organizations. Problems have resulted from mass sickle cell screening,…

Tendon Reconstruction with Tissue Engineering Approach--A Review.

PubMed

Verdiyeva, Gunay; Koshy, Kiron; Glibbery, Natalia; Mann, Haroon; Seifalian, Alexander M

2015-09-01

Tendon injuries are a common and rising occurrence, associated with significant impairment to quality of life and financial burden to the healthcare system. Clinically, they represent an unresolved problem, due to poor natural tendon healing and the inability of current treatment strategies to restore the tendon to its native state. Tissue engineering offers a promising alternative, with the incorporation of scaffolds, cells and growth factors to support the complete regeneration of the tendon. The materials used in tendon engineering to date have provided significant advances in structural integrity and biological compatibility and in many cases the results obtained are superior to those observed in natural healing. However, grafts fail to reproduce the qualities of the pre-injured tendon and each has weaknesses subject to its constituent parts. Furthermore, many materials and cell types are being investigated concurrently, with seemingly little association or comparison between research results. In this review the properties of the most-investigated and effective components have been appraised in light of the surrounding literature, with research from early in-vitro experiments to clinical trials being discussed. Extensive comparisons have been made between scaffolds, cell types and growth factors used, listing strengths and weaknesses to provide a stable platform for future research. Promising future endeavours are also described in the field of nanocomposite material science, stem cell sources and growth factors, which may bypass weaknesses found in individual elements. The future of tendon engineering looks bright, with growing understanding in material technology, cell and growth factor application and encouraging recent advances bringing us ever closer to regenerating the native tendon.

Unproven stem cell-based interventions and achieving a compromise policy among the multiple stakeholders.

PubMed

Matthews, Kirstin R W; Iltis, Ana S

2015-11-04

In 2004, patient advocate groups were major players in helping pass and implement significant public policy and funding initiatives in stem cells and regenerative medicine. In the following years, advocates were also actively engaged in Washington DC, encouraging policy makers to broaden embryonic stem cell research funding, which was ultimately passed after President Barack Obama came into office. Many advocates did this because they were told stem cell research would lead to cures. After waiting more than 10 years, many of these same patients are now approaching clinics around the world offering experimental stem cell-based interventions instead of waiting for scientists in the US to complete clinical trials. How did the same groups who were once (and often still are) the strongest supporters of stem cell research become stem cell tourists? And how can scientists, clinicians, and regulators work to bring stem cell patients back home to the US and into the clinical trial process? In this paper, we argue that the continued marketing and use of experimental stem cell-based interventions is problematic and unsustainable. Central problems include the lack of patient protection, US liability standards, regulation of clinical sites, and clinician licensing. These interventions have insufficient evidence of safety and efficacy; patients may be wasting money and time, and they may be forgoing other opportunities for an intervention that has not been shown to be safe and effective. Current practices do not contribute to scientific progress because the data from the procedures are unsuitable for follow-up research to measure outcomes. In addition, there is no assurance for patients that they are receiving the interventions promised or of what dosage they are receiving. Furthermore, there is inconsistent or non-existent follow-up care. Public policy should be developed to correct the current situation. The current landscape of stem cell tourism should prompt a re-evaluation of current approaches to study cell-based interventions with respect to the design, initiation, and conduct of US clinical trials. Stakeholders, including scientists, clinicians, regulators and patient advocates, need to work together to find a compromise to keep patients in the US and within the clinical trial process. Using HIV/AIDS and breast cancer advocate cases as examples, we identify key priorities and goals for this policy effort.

Secretome within the bone marrow microenvironment: A basis for mesenchymal stem cell treatment and role in cancer dormancy.

PubMed

Eltoukhy, Hussam S; Sinha, Garima; Moore, Caitlyn; Gergues, Marina; Rameshwar, Pranela

2018-05-31

The secretome produced by cells within the bone marrow is significant to homeostasis. The bone marrow, a well-studied organ, has multiple niches with distinct roles for supporting stem cell functions. Thus, an understanding of mediators involved in the regulation of stem cells could serve as a model for clinical problems and solutions such as tissue repair and regeneration. The exosome secretome of bone marrow stem cells is a developing area of research with respect to the regenerative potential by bone marrow cell, particularly the mesenchymal stem cells. The bone marrow niche regulates endogenous processes such as hematopoiesis but could also support the survival of tumors such as facilitating the cancer stem cells to exist in dormancy for decades. The bone marrow-derived secretome will be critical to future development of therapeutic strategies for oncologic diseases, in addition to regenerative medicine. This article discusses the importance for parallel studies to determine how the same secretome may compromise safety during the use of stem cells in regenerative medicine. Copyright © 2018 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

European network using fish as osteoporosis research models (ENFORM)

NASA Astrophysics Data System (ADS)

Goerlich, R.; Renn, J.; Alestrom, P.; Nouizadeh-Lillabadi, R.; Schartl, M.; Winkler, C.; Muller, M.; Midtyng, P. J.; Eberius, M.; Slenzka, K.

2005-08-01

Osteoporosis, characterised by loss of bone density, is one of the most important bone diseases of humans worldwide. It causes problems in post-menopausal women, in astronauts during long-term spaceflights and in industrial animal production. Bone alterations leading to osteoporosis are well-documented at the cellular level, but the underlying molecular events are still poorly understood and most of our knowledge is derived from in vitro studies using cell culture systems. Recent findings indicate a remarkable conservation of the key regulators of bone development and homeostasis between mammals and fish. Medaka (Oryzias latipes) and zebrafish (Danio rerio) offer experimental advantages that can be exploited for bone research.

Evaluation of new collision-pair selection models in DSMC

NASA Astrophysics Data System (ADS)

Akhlaghi, Hassan; Roohi, Ehsan

2017-10-01

The current paper investigates new collision-pair selection procedures in a direct simulation Monte Carlo (DSMC) method. Collision partner selection based on the random procedure from nearest neighbor particles and deterministic selection of nearest neighbor particles have already been introduced as schemes that provide accurate results in a wide range of problems. In the current research, new collision-pair selections based on the time spacing and direction of the relative movement of particles are introduced and evaluated. Comparisons between the new and existing algorithms are made considering appropriate test cases including fluctuations in homogeneous gas, 2D equilibrium flow, and Fourier flow problem. Distribution functions for number of particles and collisions in cell, velocity components, and collisional parameters (collision separation, time spacing, relative velocity, and the angle between relative movements of particles) are investigated and compared with existing analytical relations for each model. The capability of each model in the prediction of the heat flux in the Fourier problem at different cell numbers, numbers of particles, and time steps is examined. For new and existing collision-pair selection schemes, the effect of an alternative formula for the number of collision-pair selections and avoiding repetitive collisions are investigated via the prediction of the Fourier heat flux. The simulation results demonstrate the advantages and weaknesses of each model in different test cases.

A tesselated probabilistic representation for spatial robot perception and navigation

NASA Technical Reports Server (NTRS)

Elfes, Alberto

1989-01-01

The ability to recover robust spatial descriptions from sensory information and to efficiently utilize these descriptions in appropriate planning and problem-solving activities are crucial requirements for the development of more powerful robotic systems. Traditional approaches to sensor interpretation, with their emphasis on geometric models, are of limited use for autonomous mobile robots operating in and exploring unknown and unstructured environments. Here, researchers present a new approach to robot perception that addresses such scenarios using a probabilistic tesselated representation of spatial information called the Occupancy Grid. The Occupancy Grid is a multi-dimensional random field that maintains stochastic estimates of the occupancy state of each cell in the grid. The cell estimates are obtained by interpreting incoming range readings using probabilistic models that capture the uncertainty in the spatial information provided by the sensor. A Bayesian estimation procedure allows the incremental updating of the map using readings taken from several sensors over multiple points of view. An overview of the Occupancy Grid framework is given, and its application to a number of problems in mobile robot mapping and navigation are illustrated. It is argued that a number of robotic problem-solving activities can be performed directly on the Occupancy Grid representation. Some parallels are drawn between operations on Occupancy Grids and related image processing operations.

Fuel cells feasibility

NASA Technical Reports Server (NTRS)

Schonfeld, D.; Charng, T.

1981-01-01

The technical and economic status of fuel cells is assessed with emphasis on their potential benefits to the Deep Space Network. The fuel cell, what it is, how it operates, and what its outputs are, is reviewed. Major technical problems of the fuel cell and its components are highlighted. Due to these problems and economic considerations it is concluded that fuel cells will not become commercially viable until the early 1990s.

MATCHED FILTER COMPUTATION ON FPGA, CELL, AND GPU

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

BAKER, ZACHARY K.; GOKHALE, MAYA B.; TRIPP, JUSTIN L.

2007-01-08

The matched filter is an important kernel in the processing of hyperspectral data. The filter enables researchers to sift useful data from instruments that span large frequency bands. In this work, they evaluate the performance of a matched filter algorithm implementation on accelerated co-processor (XD1000), the IBM Cell microprocessor, and the NVIDIA GeForce 6900 GTX GPU graphics card. They provide extensive discussion of the challenges and opportunities afforded by each platform. In particular, they explore the problems of partitioning the filter most efficiently between the host CPU and the co-processor. Using their results, they derive several performance metrics that providemore » the optimal solution for a variety of application situations.« less

Pancreatic cancer biology and genetics from an evolutionary perspective

PubMed Central

Makohon-Moore, Alvin; Iacobuzio-Donahue, Christine A.

2017-01-01

Cancer is an evolutionary disease, containing the hallmarks of an asexually reproducing unicellular organism subject to evolutionary paradigms. Pancreatic ductal adenocarcinoma (hereafter referred to as pancreatic cancer) is a particularly robust example of this phenomenon. Genomic features indicate that pancreatic cancer cells are selected for fitness advantages when encountering the geographic and resource-depleted constraints of the microenvironment. Phenotypic adaptations to these pressures help disseminated cells to survive in secondary sites, a major clinical problem for patients with this disease. In this Review we gather the wide-ranging aspects of pancreatic cancer research into a single concept rooted in Darwinian evolution, with the goal of identifying novel insights and opportunities for study. PMID:27444064

Repair Mechanism of UV-damaged DNA in Xeroderma Pigmentosum | Center for Cancer Research

Cancer.gov

Xeroderma pigmentosum (XP) is a rare, inherited disorder characterized by extreme skin sensitivity to ultraviolet (UV) rays from sunlight. XP is caused by mutations in genes involved in nucleotide excision repair (NER) of damaged DNA. Normal cells are usually able to fix this damage before it leads to problems; however, the DNA damage is not repaired normally in patients with XP. As more abnormalities form in DNA, cells malfunction and eventually become cancerous or die. XP patients have more than a 10,000-fold increased risk of developing skin cancer. Kenneth Kraemer, M.D., in CCR’s Dermatology Branch, has been studying XP patients at the Clinical Center for more than 40 years.

Human Brain Microvascular Endothelial Cells Derived from the BC1 iPS Cell Line Exhibit a Blood-Brain Barrier Phenotype.

PubMed

Katt, Moriah E; Xu, Zinnia S; Gerecht, Sharon; Searson, Peter C

2016-01-01

The endothelial cells that form capillaries in the brain are highly specialized, with tight junctions that minimize paracellular transport and an array of broad-spectrum efflux pumps that make drug delivery to the brain extremely challenging. One of the major limitations in blood-brain barrier research and the development of drugs to treat central nervous system diseases is the lack of appropriate cell lines. Recent reports indicate that the derivation of human brain microvascular endothelial cells (hBMECs) from human induced pluripotent stem cells (iPSCs) may provide a solution to this problem. Here we demonstrate the derivation of hBMECs extended to two new human iPSC lines: BC1 and GFP-labeled BC1. These hBMECs highly express adherens and tight junction proteins VE-cadherin, ZO-1, occludin, and claudin-5. The addition of retinoic acid upregulates VE-cadherin expression, and results in a significant increase in transendothelial electrical resistance to physiological values. The permeabilities of tacrine, rhodamine 123, and Lucifer yellow are similar to values obtained for MDCK cells. The efflux ratio for rhodamine 123 across hBMECs is in the range 2-4 indicating polarization of efflux transporters. Using the rod assay to assess cell organization in small vessels and capillaries, we show that hBMECs resist elongation with decreasing diameter but show progressive axial alignment. The derivation of hBMECs with a blood-brain barrier phenotype from the BC1 cell line highlights that the protocol is robust. The expression of GFP in hBMECs derived from the BC1-GFP cell line provides an important new resource for BBB research.

Facial fluid synthesis for assessment of acne vulgaris using luminescent visualization system through optical imaging and integration of fluorescent imaging system

NASA Astrophysics Data System (ADS)

Balbin, Jessie R.; Dela Cruz, Jennifer C.; Camba, Clarisse O.; Gozo, Angelo D.; Jimenez, Sheena Mariz B.; Tribiana, Aivje C.

2017-06-01

Acne vulgaris, commonly called as acne, is a skin problem that occurs when oil and dead skin cells clog up in a person's pores. This is because hormones change which makes the skin oilier. The problem is people really do not know the real assessment of sensitivity of their skin in terms of fluid development on their faces that tends to develop acne vulgaris, thus having more complications. This research aims to assess Acne Vulgaris using luminescent visualization system through optical imaging and integration of image processing algorithms. Specifically, this research aims to design a prototype for facial fluid analysis using luminescent visualization system through optical imaging and integration of fluorescent imaging system, and to classify different facial fluids present in each person. Throughout the process, some structures and layers of the face will be excluded, leaving only a mapped facial structure with acne regions. Facial fluid regions are distinguished from the acne region as they are characterized differently.

Getting mitochondria to center stage

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

Schatz, Gottfried, E-mail: gottfried.schatz@unibas.ch

2013-05-10

The question of how eukaryotic cells assemble their mitochondria was long considered to be inaccessible to biochemical investigation. This attitude changed about fifty years ago when the powerful tools of yeast genetics, electron microscopy and molecular biology were brought to bear on this problem. The rising interest in mitochondrial biogenesis thus paralleled and assisted in the birth of modern biology. This brief recollection recounts the days when research on mitochondrial biogenesis was an exotic effort limited to a small group of outsiders.

Tackling breast cancer chemoresistance with nano-formulated siRNA

PubMed Central

Jones, SK; Merkel, OM

2017-01-01

Breast cancer is the leading cancer diagnosed in women and the second leading cause of cancer-related deaths in women. Current limitations to standard chemotherapy in the clinic are extensively researched, including problems arising from repeated treatments with the same drugs. The phenomenon that cancer cells become resistant toward certain chemo drugs is called chemotherapy resistance. In this review, we are focusing on nanoformulation of siRNA for the fight against breast cancer chemoresistance. PMID:27648580

Overview of past, present and future marine power plants

NASA Astrophysics Data System (ADS)

Morsy El-Gohary, M.

2013-06-01

In efforts to overcome an foreseeable energy crisis predicated on limited oil and gas supplies, reserves; economic variations facing the world, and of course the environmental side effects of fossil fuels, an urgent need for energy sources that provide sustainable, safe and economic supplies for the world is imperative. The current fossil fuel energy system must be improved to ensure a better and cleaner transportation future for the world. Despite the fact that the marine transportation sector consumes only 5% of global petroleum production; it is responsible for 15% of the world NO x and SO x emissions. These figures must be the engine that powers the scientific research worldwide to develop new solutions for a very old energy problem. In this paper, the most effective types of marine power plants were discussed. The history of the development of each type was presented first and the technical aspects were discussed second. Also, the fuel cells as a new type of power plants used in marine sector were briefed to give a complete overview of the past, present and future of the marine power plants development. Based on the increased worldwide concerns regarding harmful emissions, many researchers have introduced solutions to this problem, including the adoption of new cleaner fuels. This paper was guided using the same trend and by implementing the hydrogen as fuel for marine internal combustion engine, gas turbines, and fuel cells.

[Clinical Development of Immune Checkpoint Inhibitors in Patients with Small Cell Lung Cancer].

PubMed

Zhang, Shuang; Liu, Jingjing; Cheng, Ying

2017-09-20

Small cell lung cancer (SCLC) is a poorly differentiated high-grade neuroendocrine tumor, accounts for approximately 14% of all lung cancers. SCLC is characterized by rapid growth, early metastasis without effective treatments after recurrence. It is urgently need to improve the therapy of patients with SCLC. In recent years Tumor immunotherapy has shown promising efficacy, especially in immune checkpoints including inhibitors programmed cell-death protein 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4). These immune checkpoint inhibitors of the researches are changing the clinical practice of many kinds of solid tumor. SCLC is a potential ideal type of tumor immunotherapy for tobacco exposure and the highest mutational load. In this report, the authors review the current state of the immunotherapy in SCLC, to discussing the problems, challenge and application development prospect.

Automated solar cell assembly team process research

NASA Astrophysics Data System (ADS)

Nowlan, M. J.; Hogan, S. J.; Darkazalli, G.; Breen, W. F.; Murach, J. M.; Sutherland, S. F.; Patterson, J. S.

1994-06-01

This report describes work done under the Photovoltaic Manufacturing Technology (PVMaT) project, Phase 3A, which addresses problems that are generic to the photovoltaic (PV) industry. Spire's objective during Phase 3A was to use its light soldering technology and experience to design and fabricate solar cell tabbing and interconnecting equipment to develop new, high-yield, high-throughput, fully automated processes for tabbing and interconnecting thin cells. Areas that were addressed include processing rates, process control, yield, throughput, material utilization efficiency, and increased use of automation. Spire teamed with Solec International, a PV module manufacturer, and the University of Massachusetts at Lowell's Center for Productivity Enhancement (CPE), automation specialists, who are lower-tier subcontractors. A number of other PV manufacturers, including Siemens Solar, Mobil Solar, Solar Web, and Texas instruments, agreed to evaluate the processes developed under this program.

[Nutrigenetics and nutrigenomics - application of „omics” technologies in optimization of human nutrition].

PubMed

Panczyk, Mariusz

2013-01-01

Nowadays nutrigenetics and nutrigenomics are perceived as one of the most important research areas ensuring better understanding of an impact of nutrition on human health. Since such researches are interdisciplinary in type, there is a problem with their widespread acceptance and practical clinical application of obtained results. Understanding the new ideas and hypotheses published in researches on nutrigenetics/nutrigenomics requires some knowledge of genetics, biochemistry, molecular biology, and capabilities and limitations that are associated with the use of statistical and bioinformatic analysis, and above all „omics” research technologies (genomics, transcriptomics, proteomics, metabolomics). Highly efficient genome and proteome analysis techniques allow to obtain data necessary for profiling of an individual patient. The main problem is still our insufficient knowledge of cell physiology and biochemistry. The vast amount of information is obtained with the use of „omics” technologies what makes it difficult to interpret and infer. An unquestionable advantage of this type of research is the possibility to utilize system analysis (system biology) which is important in the context of a holistic interpretation of biological phenomena. This review is an attempt to present the main hypotheses and objectives which are carried out by researchers in nutrigenetics/nutrigenomics. This article describes the most important directions of research and anticipated results that are related to the practical use of nutritional genomics as well as the critical assessment of the possible impact of future developments on public health.

Establishment of novel detection system for embryonic stem cell-derived hepatocyte-like cells based on nongenetic manipulation with indocyanine green.

PubMed

Yoshie, Susumu; Ito, Jun; Shirasawa, Sakiko; Yokoyama, Tadayuki; Fujimura, Yuu; Takeda, Kazuo; Mizuguchi, Masahiro; Matsumoto, Ken; Tomotsune, Daihachiro; Sasaki, Katsunori

2012-01-01

Hepatocytes derived from embryonic stem cells (ESCs) are expected to be useful for basic research and clinical applications. However, in several studies, genetic methods used to detect and obtain them are difficult and pose major safety problems. Therefore, in this study, we established a novel detection system for hepatocytes by using indocyanine green (ICG), which is selectively taken up by hepatocytes, based on nongenetic manipulation. ICG has maximum light absorption near 780 nm, and it fluoresces between 800 and 900 nm. Making use of these properties, we developed flow cytometry equipped with an excitation lazer of 785 nm and specific bandpass filters and successfully detected ESC-derived ICG-positive cells that were periodic acid-Schiff positive and expressed hepatocyte phenotypic mRNAs. These results demonstrate that this detection system based on nongenetic manipulation with ICG will lead to isolate hepatocytes generated from ESCs and provide the appropriate levels of stability, quality, and safety required for cell source for cell-based therapy and pharmaceutical studies such as toxicology.

Network embedding-based representation learning for single cell RNA-seq data.

PubMed

Li, Xiangyu; Chen, Weizheng; Chen, Yang; Zhang, Xuegong; Gu, Jin; Zhang, Michael Q

2017-11-02

Single cell RNA-seq (scRNA-seq) techniques can reveal valuable insights of cell-to-cell heterogeneities. Projection of high-dimensional data into a low-dimensional subspace is a powerful strategy in general for mining such big data. However, scRNA-seq suffers from higher noise and lower coverage than traditional bulk RNA-seq, hence bringing in new computational difficulties. One major challenge is how to deal with the frequent drop-out events. The events, usually caused by the stochastic burst effect in gene transcription and the technical failure of RNA transcript capture, often render traditional dimension reduction methods work inefficiently. To overcome this problem, we have developed a novel Single Cell Representation Learning (SCRL) method based on network embedding. This method can efficiently implement data-driven non-linear projection and incorporate prior biological knowledge (such as pathway information) to learn more meaningful low-dimensional representations for both cells and genes. Benchmark results show that SCRL outperforms other dimensional reduction methods on several recent scRNA-seq datasets. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

Cell light scattering characteristic numerical simulation research based on FDTD algorithm

NASA Astrophysics Data System (ADS)

Lin, Xiaogang; Wan, Nan; Zhu, Hao; Weng, Lingdong

2017-01-01

In this study, finite-difference time-domain (FDTD) algorithm has been used to work out the cell light scattering problem. Before beginning to do the simulation contrast, finding out the changes or the differences between normal cells and abnormal cells which may be cancerous or maldevelopment is necessary. The preparation of simulation are building up the simple cell model of cell which consists of organelles, nucleus and cytoplasm and setting up the suitable precision of mesh. Meanwhile, setting up the total field scattering field source as the excitation source and far field projection analysis group is also important. Every step need to be explained by the principles of mathematic such as the numerical dispersion, perfect matched layer boundary condition and near-far field extrapolation. The consequences of simulation indicated that the position of nucleus changed will increase the back scattering intensity and the significant difference on the peak value of scattering intensity may result from the changes of the size of cytoplasm. The study may help us find out the regulations based on the simulation consequences and the regulations can be meaningful for early diagnosis of cancers.

Single-cell transcriptomics for microbial eukaryotes.

PubMed

Kolisko, Martin; Boscaro, Vittorio; Burki, Fabien; Lynn, Denis H; Keeling, Patrick J

2014-11-17

One of the greatest hindrances to a comprehensive understanding of microbial genomics, cell biology, ecology, and evolution is that most microbial life is not in culture. Solutions to this problem have mainly focused on whole-community surveys like metagenomics, but these analyses inevitably loose information and present particular challenges for eukaryotes, which are relatively rare and possess large, gene-sparse genomes. Single-cell analyses present an alternative solution that allows for specific species to be targeted, while retaining information on cellular identity, morphology, and partitioning of activities within microbial communities. Single-cell transcriptomics, pioneered in medical research, offers particular potential advantages for uncultivated eukaryotes, but the efficiency and biases have not been tested. Here we describe a simple and reproducible method for single-cell transcriptomics using manually isolated cells from five model ciliate species; we examine impacts of amplification bias and contamination, and compare the efficacy of gene discovery to traditional culture-based transcriptomics. Gene discovery using single-cell transcriptomes was found to be comparable to mass-culture methods, suggesting single-cell transcriptomics is an efficient entry point into genomic data from the vast majority of eukaryotic biodiversity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Feasibility studies of oncornavirus production in microcarrier cultures.

PubMed

Manousos, M; Ahmed, M; Torchio, C; Wolff, J; Shibley, G; Stephens, R; Mayyasi, S

1980-06-01

Studies conducted with virus-infected monolayer cell cultures have demonstrated the feasibility of producing several tumor-associated viruses in microcarrier (mc) cultures (Sephadex G50 beads treated with DEAE-chloride). The efficiency of cell adherence to mc varied with the cell type, the pH of the growth medium, and the stirring force applied to keep the mc in suspension. Most cells attached firmly to the mc and could not be removed easily with routine trypsinization procedures. Techniques using Enzar-T and Pronase were effective in detaching cells from mc in 10 to 15 min while retaining 95% cell viability. After detachment, Ficoll gradients were used for rapid and complete separation of viable cell suspensions from the mc. Retrovirus production in large volumes of mc cultures was investigated with periodic harvesting of growth fluids. Physical, biochemical, and biological properties of the Mason-Pfizer monkey virus and the RD114 virus recovered from the mc cultures were identical to those produced in conventional cultures. The utilization of mc has several applications in research and short-term cultures, but the as-yet-unsolved technical problems met were found to be serious limitations when attempting mass cell culturing on a long-term basis.

Technology advancement for integrative stem cell analyses.

PubMed

Jeong, Yoon; Choi, Jonghoon; Lee, Kwan Hyi

2014-12-01

Scientists have endeavored to use stem cells for a variety of applications ranging from basic science research to translational medicine. Population-based characterization of such stem cells, while providing an important foundation to further development, often disregard the heterogeneity inherent among individual constituents within a given population. The population-based analysis and characterization of stem cells and the problems associated with such a blanket approach only underscore the need for the development of new analytical technology. In this article, we review current stem cell analytical technologies, along with the advantages and disadvantages of each, followed by applications of these technologies in the field of stem cells. Furthermore, while recent advances in micro/nano technology have led to a growth in the stem cell analytical field, underlying architectural concepts allow only for a vertical analytical approach, in which different desirable parameters are obtained from multiple individual experiments and there are many technical challenges that limit vertically integrated analytical tools. Therefore, we propose--by introducing a concept of vertical and horizontal approach--that there is the need of adequate methods to the integration of information, such that multiple descriptive parameters from a stem cell can be obtained from a single experiment.

Technology Advancement for Integrative Stem Cell Analyses

PubMed Central

Jeong, Yoon

2014-01-01

Scientists have endeavored to use stem cells for a variety of applications ranging from basic science research to translational medicine. Population-based characterization of such stem cells, while providing an important foundation to further development, often disregard the heterogeneity inherent among individual constituents within a given population. The population-based analysis and characterization of stem cells and the problems associated with such a blanket approach only underscore the need for the development of new analytical technology. In this article, we review current stem cell analytical technologies, along with the advantages and disadvantages of each, followed by applications of these technologies in the field of stem cells. Furthermore, while recent advances in micro/nano technology have led to a growth in the stem cell analytical field, underlying architectural concepts allow only for a vertical analytical approach, in which different desirable parameters are obtained from multiple individual experiments and there are many technical challenges that limit vertically integrated analytical tools. Therefore, we propose—by introducing a concept of vertical and horizontal approach—that there is the need of adequate methods to the integration of information, such that multiple descriptive parameters from a stem cell can be obtained from a single experiment. PMID:24874188

Advances toward regenerative medicine in the central nervous system: challenges in making stem cell therapy a viable clinical strategy.

PubMed

Stoll, Elizabeth A

2014-01-01

Over recent years, there has been a great deal of interest in the prospects of stem cell-based therapies for the treatment of nervous system disorders. The eagerness of scientists, clinicians, and spin-out companies to develop new therapies led to premature clinical trials in human patients, and now the initial excitement has largely turned to skepticism. Rather than embracing a defeatist attitude or pressing blindly ahead, I argue it is time to evaluate the challenges encountered by regenerative medicine in the central nervous system and the progress that is being made to solve these problems. In the twenty years since the adult brain was discovered to have an endogenous regenerative capacity, much basic research has been done to elucidate mechanisms controlling proliferation and cellular identity; how stem cells may be directed into neuronal lineages; genetic, pharmacological, and behavioral interventions that modulate neurogenic activity; and the exact nature of limitations to regeneration in the adult, aged, diseased and injured CNS. These findings should prove valuable in designing realistic clinical strategies to improve the prospects of stem cell-based therapies. In this review, I discuss how basic research continues to play a critical role in identifying both barriers and potential routes to regenerative therapy in the CNS.

Artificial Cell Therapy: New Strategies for the Therapeutic Delivery of Live Bacteria

PubMed Central

2005-01-01

There has been rapid growth in research regarding the use of live bacterial cells for therapeutic purposes. The recognition that these cells can be genetically engineered to synthesize products that have therapeutic potential has generated considerable interest and excitement among clinicians and health professionals. It is expected that a wide range of disease modifying substrates such as enzymes, hormones, antibodies, vaccines, and other genetic products will be used successfully and will impact upon health care substantially. However, a major limitation in the use of these bacterial cells is the complexity of delivering them to the correct target tissues. Oral delivery of live cells, lyophilized cells, and immobilized cells has been attempted but with limited success. Primarily, this is because bacterial cells are incapable of surviving passage through the gastrointestinal tract. In many occasions, when given orally, these cells have been found to provoke immunogenic responses that are undesirable. Recent studies show that these problems can be overcome by delivering live bacterial cells, such as genetically engineered cells, using artificial cell microcapsules. This review summarizes recent advances in the therapeutic use of live bacterial cells for therapy, discusses the principles of using artificial cells for the oral delivery of bacterial cells, outlines methods for preparing suitable artificial cells for this purpose, addresses potentials and limitations for their application in therapy, and provides insight for the future direction of this emergent and highly prospective technology. PMID:15689638

Multivariate Calibration Approach for Quantitative Determination of Cell-Line Cross Contamination by Intact Cell Mass Spectrometry and Artificial Neural Networks.

PubMed

Valletta, Elisa; Kučera, Lukáš; Prokeš, Lubomír; Amato, Filippo; Pivetta, Tiziana; Hampl, Aleš; Havel, Josef; Vaňhara, Petr

2016-01-01

Cross-contamination of eukaryotic cell lines used in biomedical research represents a highly relevant problem. Analysis of repetitive DNA sequences, such as Short Tandem Repeats (STR), or Simple Sequence Repeats (SSR), is a widely accepted, simple, and commercially available technique to authenticate cell lines. However, it provides only qualitative information that depends on the extent of reference databases for interpretation. In this work, we developed and validated a rapid and routinely applicable method for evaluation of cell culture cross-contamination levels based on mass spectrometric fingerprints of intact mammalian cells coupled with artificial neural networks (ANNs). We used human embryonic stem cells (hESCs) contaminated by either mouse embryonic stem cells (mESCs) or mouse embryonic fibroblasts (MEFs) as a model. We determined the contamination level using a mass spectra database of known calibration mixtures that served as training input for an ANN. The ANN was then capable of correct quantification of the level of contamination of hESCs by mESCs or MEFs. We demonstrate that MS analysis, when linked to proper mathematical instruments, is a tangible tool for unraveling and quantifying heterogeneity in cell cultures. The analysis is applicable in routine scenarios for cell authentication and/or cell phenotyping in general.

Multivariate Calibration Approach for Quantitative Determination of Cell-Line Cross Contamination by Intact Cell Mass Spectrometry and Artificial Neural Networks

PubMed Central

Prokeš, Lubomír; Amato, Filippo; Pivetta, Tiziana; Hampl, Aleš; Havel, Josef; Vaňhara, Petr

2016-01-01

Cross-contamination of eukaryotic cell lines used in biomedical research represents a highly relevant problem. Analysis of repetitive DNA sequences, such as Short Tandem Repeats (STR), or Simple Sequence Repeats (SSR), is a widely accepted, simple, and commercially available technique to authenticate cell lines. However, it provides only qualitative information that depends on the extent of reference databases for interpretation. In this work, we developed and validated a rapid and routinely applicable method for evaluation of cell culture cross-contamination levels based on mass spectrometric fingerprints of intact mammalian cells coupled with artificial neural networks (ANNs). We used human embryonic stem cells (hESCs) contaminated by either mouse embryonic stem cells (mESCs) or mouse embryonic fibroblasts (MEFs) as a model. We determined the contamination level using a mass spectra database of known calibration mixtures that served as training input for an ANN. The ANN was then capable of correct quantification of the level of contamination of hESCs by mESCs or MEFs. We demonstrate that MS analysis, when linked to proper mathematical instruments, is a tangible tool for unraveling and quantifying heterogeneity in cell cultures. The analysis is applicable in routine scenarios for cell authentication and/or cell phenotyping in general. PMID:26821236

Aspects of emotional functioning following oesophageal cancer surgery in a population-based cohort study.

PubMed

Hellstadius, Ylva; Lagergren, Pernilla; Lagergren, Jesper; Johar, Asif; Hultman, Christina M; Wikman, Anna

2015-01-01

The aim of this study was to establish the proportion of patients reporting emotional problems following oesophagectomy for cancer and identify the risk characteristics for emotional problems. A Swedish population-based cohort study of patients with surgically treated oesophageal cancer was used. The European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 was used to assess tension, worry, irritation and depressed mood at 6 months and 5 years after surgery. Potential risk characteristics were retrieved from medical notes and data linkages to Swedish health registries. Multivariable logistic regression analyses were performed to examine risk characteristics for poor emotional recovery. Of 401 patients included at 6 months, 49% reported problems with tension, 61% worry, 62% irritation and 63% depressed mood. Of the 140 (35%) patients who completed the 5-year follow-up, 39% reported problems with tension and about half of the patients reported problems with worry, irritation, and depressed mood (49, 45 and 52%, respectively). Squamous cell carcinoma was identified as a risk characteristic for tension (OR 2.15, 95% CI 1.30-3.55), worry (OR 2.02, 95% CI 1.19-3.40) and depressed mood (OR 1.71, 95% CI 1.01-2.90) at 6 months compared with adenocarcinoma. Compared with higher education, lower education was associated with tension (upper secondary schooling: OR 1.97, 95% CI 1.02-3.79 and 9-year compulsory: OR 2.46, 95% CI 1.28-4.74), while non-cohabitating patients were less likely to report problems with worry at 6 months (OR 0.53, 95% CI 0.34-0.84) compared with cohabitating patients. A substantial proportion of patients reports emotional problems following oesophagectomy, and risk characteristics include squamous cell carcinoma histology and low educational level. Copyright © 2014 John Wiley & Sons, Ltd.

An adaptive simplex cut-cell method for high-order discontinuous Galerkin discretizations of elliptic interface problems and conjugate heat transfer problems

NASA Astrophysics Data System (ADS)

Sun, Huafei; Darmofal, David L.

2014-12-01

In this paper we propose a new high-order solution framework for interface problems on non-interface-conforming meshes. The framework consists of a discontinuous Galerkin (DG) discretization, a simplex cut-cell technique, and an output-based adaptive scheme. We first present a DG discretization with a dual-consistent output evaluation for elliptic interface problems on interface-conforming meshes, and then extend the method to handle multi-physics interface problems, in particular conjugate heat transfer (CHT) problems. The method is then applied to non-interface-conforming meshes using a cut-cell technique, where the interface definition is completely separate from the mesh generation process. No assumption is made on the interface shape (other than Lipschitz continuity). We then equip our strategy with an output-based adaptive scheme for an accurate output prediction. Through numerical examples, we demonstrate high-order convergence for elliptic interface problems and CHT problems with both smooth and non-smooth interface shapes.

Resource Letter RPS-1: Research in problem solving

NASA Astrophysics Data System (ADS)

Hsu, Leonardo; Brewe, Eric; Foster, Thomas M.; Harper, Kathleen A.

2004-09-01

This Resource Letter provides a guide to the literature on research in problem solving, especially in physics. The references were compiled with two audiences in mind: physicists who are (or might become) engaged in research on problem solving, and physics instructors who are interested in using research results to improve their students' learning of problem solving. In addition to general references, journal articles and books are cited for the following topics: cognitive aspects of problem solving, expert-novice problem-solver characteristics, problem solving in mathematics, alternative problem types, curricular interventions, and the use of computers in problem solving.

Cell and tissue engineering and clinical applications: an overview.

PubMed

Stoltz, J F; Bensoussan, D; Decot, V; Ciree, A; Netter, P; Gillet, P

2006-01-01

Most human tissues do not regenerate spontaneously; this is why cell therapies and tissue engineering are promising alternatives. The principle is simple: cells are collected in a patient and introduced in the damaged tissue or in a tridimentional porous support and harvested in a bioreactor in which the physico-chemical and mechanical parameters are controlled. Once the tissues (or the cells) are mature they may be implanted. In parallel, the development of biotherapies with stem cells is a field of research in turmoil given the hopes for clinical applications that it brings up. Embryonic stem cells are potentially more interesting since they are totipotent, but they can only be obtained at the very early stages of the embryo. The potential of adult stem cells is limited but isolating them induces no ethical problem and it has been known for more than 40 years that bone marrow does possess the regenerating functions of blood cells. Finally, the properties of foetal stem cells (blood cells from the umbilical cord) are forerunners of the haematopoietic system but the ability of these cells to participate to the formation of other tissues is more problematic. Another field for therapeutic research is that of dendritic cells, antigen presenting cells. Their efficiency in cell therapy relies on the initiation of specific immune responses. They represent a promising tool in the development of a protective immune response against antigens which the host is usually unable to generate an efficient response (melanomas, breast against cancer, prostate cancer, ..). Finally, gene therapy, has been nourishing high hopes but few clinical applications can be envisaged in the short term, although potential applications are multiple (haemophilia, myopathies, ..). A large number of clinical areas stand as candidates for clinical applications: leukaemia and cancers, cardiac insufficiency and vascular diseases, cartilage and bone repair, ligaments and tendons, liver diseases, ophthalmology, diabetes, neurological diseases (Parkinson, Huntington disease, ..), .. Various aspects of this new regenerative therapeutic medicine are developed in this work.

Resource Allocation Algorithms for the Next Generation Cellular Networks

NASA Astrophysics Data System (ADS)

Amzallag, David; Raz, Danny

This chapter describes recent results addressing resource allocation problems in the context of current and future cellular technologies. We present models that capture several fundamental aspects of planning and operating these networks, and develop new approximation algorithms providing provable good solutions for the corresponding optimization problems. We mainly focus on two families of problems: cell planning and cell selection. Cell planning deals with choosing a network of base stations that can provide the required coverage of the service area with respect to the traffic requirements, available capacities, interference, and the desired QoS. Cell selection is the process of determining the cell(s) that provide service to each mobile station. Optimizing these processes is an important step towards maximizing the utilization of current and future cellular networks.

Inverse problem of HIV cell dynamics using Genetic Algorithms

NASA Astrophysics Data System (ADS)

González, J. A.; Guzmán, F. S.

2017-01-01

In order to describe the cell dynamics of T-cells in a patient infected with HIV, we use a flavour of Perelson's model. This is a non-linear system of Ordinary Differential Equations that describes the evolution of healthy, latently infected, infected T-cell concentrations and the free viral cells. Different parameters in the equations give different dynamics. Considering the concentration of these types of cells is known for a particular patient, the inverse problem consists in estimating the parameters in the model. We solve this inverse problem using a Genetic Algorithm (GA) that minimizes the error between the solutions of the model and the data from the patient. These errors depend on the parameters of the GA, like mutation rate and population, although a detailed analysis of this dependence will be described elsewhere.

Physarum polycephalum—a new take on a classic model system

NASA Astrophysics Data System (ADS)

Oettmeier, Christina; Brix, Klaudia; Döbereiner, Hans-Günther

2017-10-01

Physarum polycephalum, literally the ‘many-headed’ slime mold, is a giant multi-nucleated but unicellular protist. Since the time of its first description, it has been the subject of a multitude of cell biological, biochemical, genetic, and lately physical studies. The enormous size of the cell, the easy method of in vitro cultivation, the unique life cycle and its highly visible internal cytoplasmic streaming have made it invaluable for investigations on cell cycle regulation, differentiation, cytoskeleton and locomotion. Research on P. polycephalum lost its prominent role when animal cell culture and genetic techniques became more advanced, thereby replacing the slime mold as a state-of-the-art model. However, research continued, driven by a small number of groups, resulting in full sequencing of the slime mold’s genome, hence reviving interest in studying molecular processes that enable the astounding features of P. polycephalum. In recent years, research on P. polycephalum has again become cutting-edge. In 2000, Japanese researcher Toshiyuki Nakagaki performed a seminal experiment showing that the slime mold is able to find the shortest route through a maze. Ever since, smart problem-solving P. polycephalum has returned from the shadows and is nowadays back to center-stage when questions regarding the origins of intelligence and cognition are discussed. The basic mechanisms with which organisms perceive their environment, integrate this information and make decisions based on this input are investigated. The aim is to find underlying universal mechanisms of decision making and awareness. If those mechanisms can be found in as primordial an organism as a slime mold, it could fundamentally change our perception of the nature and evolution of cognition.

Biocompatible fluorescent silicon nanocrystals for single-molecule tracking and fluorescence imaging

PubMed Central

Nishimura, Hirohito; Ritchie, Ken; Kasai, Rinshi S.; Goto, Miki; Morone, Nobuhiro; Sugimura, Hiroyuki; Tanaka, Koichiro; Sase, Ichiro; Yoshimura, Akihiko; Nakano, Yoshitaro; Fujiwara, Takahiro K.

2013-01-01

Fluorescence microscopy is used extensively in cell-biological and biomedical research, but it is often plagued by three major problems with the presently available fluorescent probes: photobleaching, blinking, and large size. We have addressed these problems, with special attention to single-molecule imaging, by developing biocompatible, red-emitting silicon nanocrystals (SiNCs) with a 4.1-nm hydrodynamic diameter. Methods for producing SiNCs by simple chemical etching, for hydrophilically coating them, and for conjugating them to biomolecules precisely at a 1:1 ratio have been developed. Single SiNCs neither blinked nor photobleached during a 300-min overall period observed at video rate. Single receptor molecules in the plasma membrane of living cells (using transferrin receptor) were imaged for ≥10 times longer than with other probes, making it possible for the first time to observe the internalization process of receptor molecules at the single-molecule level. Spatial variations of molecular diffusivity in the scale of 1–2 µm, i.e., a higher level of domain mosaicism in the plasma membrane, were revealed. PMID:24043702

Phenolic compounds from Viscum album tinctures enhanced antitumor activity in melanoma murine cancer cells.

PubMed

Melo, Michelle Nonato de Oliveira; Oliveira, Adriana Passos; Wiecikowski, Adalgisa Felippe; Carvalho, Renato Sampaio; Castro, Juliana de Lima; de Oliveira, Felipe Alves Gomes; Pereira, Henrique Marcelo Gualberto; da Veiga, Venicio Feo; Capella, Marcia Marques Alves; Rocha, Leandro; Holandino, Carla

2018-03-01

Cancer is one of the biggest problems in public health worldwide. Plants have been shown important role in anticancer research. Viscum album L. (Santalaceae), commonly known as mistletoe, is a semi-parasitic plant that grows on different host trees. In complementary medicine, extracts from European mistletoe ( Viscum album L.) have been used in the treatment of cancer. The study was conducted to identify chemical composition and antitumor potential of Viscum album tinctures. Chemical analysis performed by high resolution chromatography equipped with high resolution mass spectrometer identified caffeic acid, chlorogenic acid, sakuranetin, isosakuranetin, syringenin 4-O-glucoside, syringenin 4-O-apiosyl-glucoside, alangilignoside C and ligalbumoside A compounds. Some of these compounds are probably responsible for the reduction of tumoral cellular growth in a dose-dependent manner. It was observed that melanoma murine cells (B16F10) were more sensitive to V. album tinctures than human leukaemic cells (K562), besides non-tumoral cells (MA-104) had a much lower cytotoxicity to them. Apoptotic-like cells were observed under light microscopy and were confirmed by a typical DNA fragmentation pattern. Additionally, flow cytometry results using Annexin-V/FITC permitted to quantify increased expression of early and late apoptotic markers on tumoral cells, confirming augmented Sub G0 population, which was probably associated with a consistent decrease in G1, and an increase in S or G2/M populations. Results indicate the chemical composition of V. album tinctures influences the mechanisms of in vitro tumoral cell death, suggesting a potential use in cancer pharmacotherapy research.

The use of peritoneal mesothelium as a potential source of adult stem cells.

PubMed

Gotloib, L; Gotloib, L C; Khrizman, V

2007-06-01

At the dawn of the 21st century, classical curative medicine is being challenged by the fact that efforts to fight and prevent not a few diseases, are in many circumstances, beyond the power of the pharmacological armamentarium of the medical profession. On the other hand, replacement of lost function by mechanical or biophysical devices, or even by organ transplantation, prolongs life but generally derives in new and, at times, unsolvable problems. Regenerative therapy using stem cells began a revolutionary trend that may well change both the therapeutic approach to not a few of the diseases resulting from failing organs, as well as the fate and quality of life of millions of patients. The presence of pluripotent mesenchymal cells in the mesothelial monolayer as well as in the submesothelial connective tissue raises the possibility of using the peritoneal mesothelium in regenerative therapies. This perception of the problem is also based on observations made in humans as well as in laboratory animals showing bone, bone marrow, cartilaginous tissue, glomerular-like structures and creation of blood conducts, pathological situations (mesothelioma, sclerosing peritonitis), or after in vivo or ex vivo experimental interventions. The main concept emerging from this information is that peritoneal mesothelial cells are endowed with such a degree of plasticity that, if placed in the appropriate micro-environment, they have a remarkable potential to generate other mesenchymal-derived cell lines. Intensive research is required to define the best environmental conditions to take advantage of this plasticity and make the peritoneal mesothelium an actual option to be applied in regenerative medicine.

Prevalence of problematic cell phone use in an adult population in Spain as assessed by the Mobile Phone Problem Use Scale (MPPUS)

PubMed Central

de-Sola, José; Talledo, Hernán; Rubio, Gabriel

2017-01-01

Problematic cell phone use has alarmingly increased in industrialized countries in the past 10 years. For many perpetrators, it can turn into a behavioural addiction, although this is not a recognized medical condition. Although there are many tools for evaluating this use, one of the most widely used tools is the Mobile Phone Problematic Use Scale (MPPUS), which we test on a representative sample of the population in Spain to obtain an estimate of the prevalence of problematic cell phone use in our midst. The age range consists of 16–65 years, with 1,126 surveys conducted. In this population, we verify that the reliability and internal consistency of the MPPUS (α = 0.939) are maintained. Additionally, the construct validity, considering the derived factors (Abuse and Dependence, Craving and Loss of Control, and Dependence on the Social Environment) are aligned with other research and with diverse external criteria of addiction. We establish four categories of users (Casual, Regular, At Risk, and Problematic) and obtain a prevalence of 15.4% among At Risk Users and 5.1% among Problematic Users. This finding implies a total of 20.5% of Users with Problems. A binary logistic regression analysis shows that age, gender, level of education, and daily cell phone use predict problematic cell phone use. The results, based on multiple criteria, show that such problematic use shares features of recognized addictions, affecting large segments of the population and not only adolescents. PMID:28771626

Energy Conversion: Nano Solar Cell

NASA Astrophysics Data System (ADS)

Yahaya, Muhammad; Yap, Chi Chin; Mat Salleh, Muhamad

2009-09-01

Problems of fossil-fuel-induced climate change have sparked a demand for sustainable energy supply for all sectors of economy. Most laboratories continue to search for new materials and new technique to generate clean energy at affordable cost. Nanotechnology can play a major role in solving the energy problem. The prospect for solar energy using Si-based technology is not encouraging. Si photovoltaics can produce electricity at 20-30 c//kWhr with about 25% efficiency. Nanoparticles have a strong capacity to absorb light and generate more electrons for current as discovered in the recent work of organic and dye-sensitized cell. Using cheap preparation technique such as screen-printing and self-assembly growth, organic cells shows a strong potential for commercialization. Thin Films research group at National University Malaysia has been actively involved in these areas, and in this seminar, we will present a review works on nanomaterials for solar cells and particularly on hybrid organic solar cell based on ZnO nanorod arrays. The organic layer consisting of poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEHPPV) and [6, 6]-phenyl C61-butyric acid 3-ethylthiophene ester (PCBE) was spin-coated on ZnO nanorod arrays. ZnO nanorod arrays were grown on FTO glass substrates which were pre-coated with ZnO nanoparticles using a low temperature chemical solution method. A gold electrode was used as the top contact. The device gave a short circuit current density of 2.49×10-4 mA/cm2 and an open circuit voltage of 0.45 V under illumination of a projector halogen light at 100 mW/cm2.

The aryl hydrocarbon receptor and food allergy.

PubMed

Schulz, V J; Smit, J J; Pieters, R H H

2013-06-01

The immune system is important for protection against pathogens and malignant cells. However, malfunction of the immune system can also result in detrimental auto-immune diseases, inflammatory diseases, cancers and allergies. The aryl hydrocarbon receptor (AhR), present in numerous tissues and cell subsets, including cells of the immune system, plays an important role in the functioning of the immune system. Activation of the AhR is for example associated with various effects on dendritic cells (DCs), regulatory T cells and the Th1/Th2 cell balance. These cells play a major role in the development of food allergy. Food allergy is an increasing health problem in both humans and animals. Despite the knowledge in risk factors and cellular mechanisms for food allergy, no approved treatments are available yet. Recently, it has been shown that activation of the AhR by dioxin-like compounds suppresses allergic sensitization by suppressing the absolute number of precursor and effector T cells, by preserving CD4(+)CD25(+)Foxp3(+) Treg cells and by affecting DCs and their interaction with effector T cells. Future research should elucidate whether and how AhR activation can be used to interfere in food allergic responses in humans and in animals. This may lead to new prevention strategies and therapeutic possibilities for food allergy.

MAC/GMC 4.0 User's Manual: Example Problem Manual. Volume 3

NASA Technical Reports Server (NTRS)

Bednarcyk, Brett A.; Arnold, Steven M.

2002-01-01

This document is the third volume in the three volume set of User's Manuals for the Micromechanics Analysis Code with Generalized Method of Cells Version 4.0 (MAC/GMC 4.0). Volume 1 is the Theory Manual, Volume 2 is the Keywords Manual, and this document is the Example Problems Manual. MAC/GMC 4.0 is a composite material and laminate analysis software program developed at the NASA Glenn Research Center. It is based on the generalized method of cells (GMC) micromechanics theory, which provides access to the local stress and strain fields in the composite material. This access grants GMC the ability to accommodate arbitrary local models for inelastic material behavior and various types of damage and failure analysis. MAC/GMC 4.0 has been built around GMC to provide the theory with a user-friendly framework, along with a library of local inelastic, damage, and failure models. Further, application of simulated thermo-mechanical loading, generation of output results, and selection of architectures to represent the composite material, have been automated in MAC/GMC 4.0. Finally, classical lamination theory has been implemented within MAC/GMC 4.0 wherein GMC is used to model the composite material response of each ply. Consequently, the full range of GMC composite material capabilities is available for analysis of arbitrary laminate configurations as well. This volume provides in-depth descriptions of 43 example problems, which were specially designed to highlight many of the most important capabilities of the code. The actual input files associated with each example problem are distributed with the MAC/GMC 4.0 software; thus providing the user with a convenient starting point for their own specialized problems of interest.

Berkeley Lab Sheds Light on Improving Solar Cell Efficiency

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

Lawrence Berkeley National Laboratory

2007-07-20

Typical manufacturing methods produce solar cells with an efficiency of 12-15%; and 14% efficiency is the bare minimum for achieving a profit. In work performed at the Ernest Orlando Lawrence Berkeley National Laboratory (Berkeley, CA, 5 10-486-577 1)--a US Department of Energy national laboratory that conducts unclassified scientific research and is managed by the University of California--scientist Scott McHugo has obtained keen insights into the impaired performance of solar cells manufactured from polycrystalline silicon. The solar cell market is potentially vast, according to Berkeley Lab. Lightweight solar panels are highly beneficial for providing electrical power to remote locations in developingmore » nations, since there is no need to build transmission lines or truck-in generator fuel. Moreover, industrial nations confronted with diminishing resources have active programs aimed at producing improved, less expensive solar cells. 'In a solar cell, there is a junction between p-type silicon and an n-type layer, such as diffused-in phosphorous', explained McHugo, who is now with Berkeley Lab's Accelerator and Fusion Research Division. 'When sunlight is absorbed, it frees electrons, which start migrating in a random-walk fashion toward that junction. If the electrons make it to the junction; they contribute to the cell's output of electric current. Often, however, before they reach the junction, they recombine at specific sites in the crystal' (and, therefore, cannot contribute to current output). McHugo scrutinized a map of a silicon wafer in which sites of high recombination appeared as dark regions. Previously, researchers had shown that such phenomena occurred not primarily at grain boundaries in the polycrystalline material, as might be expected, but more often at dislocations in the crystal. However, the dislocations themselves were not the problem. Using a unique heat treatment technique, McHugo performed electrical measurements to investigate the material at the dislocations. He was purportedly the first to show that they were 'decorated' with iron.« less

RESEARCH RECORDS AND THE RESOLUTION OF MISCONDUCT ALLEGATIONS AT RESEARCH UNIVERSITIES

PubMed Central

WILSON, KENNETH; SCHREIER, ALAN; GRIFFIN, ANGEL; RESNIK, DAVID

2014-01-01

Accurate record keeping is an important part of the responsible conduct of research. However, there is very little empirical research on scientific record keeping. No one knows the incidence of serious problems with research records, the types of problems that occur, nor their consequences. In this study, we examined the role of research records in the resolution of misconduct allegations as a useful barometer for the incidence and types of problems that occur with records. We interviewed Research Integrity Officers (RIOs) at 90 major research universities and conducted focus groups with active research faculty. RIOs reported problems with research records in 38% of the 553 investigations they conducted. Severe problems with research records often prevented completion of investigations while problems that are more typical lengthened them by 2 to 3 weeks. Five types of poor record keeping practices accounted for 75% of the problems with incomplete/inadequate records being the most common (30%). The focus groups concurred with the findings from the interviews with RIOs, stressed the importance of the research group leader in setting and maintaining record practices, and offered additional insights. While university officials and faculty members have suspected for many years that there are serious problems with research record keeping, our study provides empirical evidence for this belief. By documenting some of the problems with record keeping in university-based research, the results of our study provide information that will be useful for policy development at academic institutions. PMID:17847607

Research records and the resolution of misconduct allegations at research universities.

PubMed

Wilson, Kenneth; Schreier, Alan; Griffin, Angel; Resnik, David

2007-01-01

Accurate record keeping is an important part of the responsible conduct of research. However, there is very little empirical research on scientific record keeping. No one knows the incidence of serious problems with research records, the types of problems that occur, nor their consequences. In this study, we examined the role of research records in the resolution of misconduct allegations as a useful barometer for the incidence and types of problems that occur with records. We interviewed Research Integrity Officers (RIOs) at 90 major research universities and conducted focus groups with active research faculty. RIOs reported problems with research records in 38% of the 553 investigations they conducted. Severe problems with research records often prevented completion of investigations while problems that are more typical lengthened them by 2 to 3 weeks. Five types of poor record keeping practices accounted for 75 % of the problems with incomplete/inadequate records being the most common (30%). The focus groups concurred with the findings from the interviews with RIOs, stressed the importance of the research group leader in setting and maintaining record practices, and offered additional insights. While university officials and faculty members have suspected for many years that there are serious problems with research record keeping, our study provides empirical evidence for this belief. By documenting some of the problems with record keeping in university-based research, the results of our study provide information that will be useful for policy development at academic institutions.

Efforts to develop a cultured sponge cell line: revisiting an intractable problem.

PubMed

Grasela, James J; Pomponi, Shirley A; Rinkevich, Buki; Grima, Jennifer

2012-01-01

Residents of the marine environment, sponges (Porifera) have the ability to produce organic compounds known as secondary metabolites, which are not directly involved in the normal growth, development, or reproduction of an organism. Because of their sessile nature, the production of these bioactive compounds has been interpreted as a functional adaptation to serve in an important survival role as a means to counter various environmental stress factors such as predation, overgrowth by fouling organisms, or competition for limited space. Regardless of the reasons for this adaptation, a variety of isolated compounds have already proven to demonstrate remarkable anticancer, fungicidal, and antibiotic properties. A major obstacle to the isolation and production of novel compounds from sponges is the lack of a large, reliable source of sponge material. Sponge collection from the sea would be environmentally detrimental to the already stressed and sparse sponge populations. Sponge production in an aquaculture setting might appear to be an ideal alternative but would also be cost-ineffective and sponge growth is extremely slow. A third approach involves the development of a sponge cell culture system capable of producing the necessary cell numbers to harvest for research purposes as well as for the eventual commercial-scale production of promising bioactive compounds. Unfortunately, little progress has been made in this direction other than the establishment of temporary cultures containing aggregates and fragments of cells. One impediment toward successful sponge cell culture might be ascribed to a lack of published knowledge of failed methodologies, and thus, time and effort is wasted on continued reinvention of the same methods and procedures. Consequently, we have undertaken here to chart some of our unsuccessful research efforts, our methodology, and results to provide the sponge research community with knowledge to assist them to better avoid taking the same failed pathways.

Design and research of built-in sample cell with multiple optical reflections

NASA Astrophysics Data System (ADS)

Liu, Jianhui; Wang, Shuyao; Lv, Jinwei; Liu, Shuyang; Zhou, Tao; Jia, Xiaodong

2017-10-01

In the field of trace gas measurement, with the characteristics of high sensitivity, high selectivity and rapid detection, tunable diode laser absorption spectroscopy (TDLAS) is widely used in industrial process and trace gas pollution monitoring. Herriott cell is a common form of multiple reflections of the sample cell, the structure of the Herriott cell is relatively simple, which be used to application of trace gas absorption spectroscopy. In the pragmatic situation, the gas components are complicated, and the continuous testing process for a long time can lead to different degree of pollution and corrosion for the reflector in the sample cell. If the mirror is not cleaned up in time, it will have a great influence on the detection accuracy. In order to solve this problem in the process of harsh environment detection, this paper presents a design of the built-in sample cell to avoid the contact of gas and the mirror, thereby effectively reducing corrosion pollution. If there is optical pollution, direct replacement of the built-in optical sample cell can easily to be disassembled, and cleaned. The advantage of this design is long optical path, high precision, cost savings and so on.

Microhydrodynamics of deformable particles: surprising responses of drops and vesicles to uniform electric field or shear flow

NASA Astrophysics Data System (ADS)

Vlahovska, Petia

2015-11-01

Particle motion in a viscous fluid is a classic problem that continues to surprise researchers. In this talk, I will discuss some intriguing, experimentally-observed behaviors of droplets and giant vesicles (cell-size lipid membrane sacs) in electric or flow fields. In a uniform electric field, a droplet deforms into an ellipsoid that can either be steadily tilted relative to the applied field direction or undergo unsteady motions (periodic shape oscillations or irregular flipping); a spherical vesicle can adopt a transient square shape or reversibly porate. In a steady shear flow, a vesicle can tank-tread, tumble or swing. Theoretical models show that the nonlinear drop dynamics originates from the interplay of Quincke rotation and interface deformation, while the vesicle dynamics stems from the membrane inextensibility. The practical motivation for this research lies in an improved understanding of technologies that rely on the manipulation of drops and cells by flow or electric fields.

Model Averaging for Predicting the Exposure to Aflatoxin B1 Using DNA Methylation in White Blood Cells of Infants

NASA Astrophysics Data System (ADS)

Rahardiantoro, S.; Sartono, B.; Kurnia, A.

2017-03-01

In recent years, DNA methylation has been the special issue to reveal the pattern of a lot of human diseases. Huge amount of data would be the inescapable phenomenon in this case. In addition, some researchers interesting to take some predictions based on these huge data, especially using regression analysis. The classical approach would be failed to take the task. Model averaging by Ando and Li [1] could be an alternative approach to face this problem. This research applied the model averaging to get the best prediction in high dimension of data. In the practice, the case study by Vargas et al [3], data of exposure to aflatoxin B1 (AFB1) and DNA methylation in white blood cells of infants in The Gambia, take the implementation of model averaging. The best ensemble model selected based on the minimum of MAPE, MAE, and MSE of predictions. The result is ensemble model by model averaging with number of predictors in model candidate is 15.

Science and technology of farm animal cloning: state of the art.

PubMed

Vajta, Gábor; Gjerris, Mickey

2006-05-01

Details of the first mammal born after nuclear transfer cloning were published by Steen Malte Willadsen in 1986. In spite of its enormous scientific significance, this discovery failed to trigger much public concern, possibly because the donor cells were derived from pre-implantation stage embryos. The major breakthrough in terms of public recognition has happened when Ian Wilmut et al. [Wilmut, I., Schnieke, A.E., McWhir, J., Kind, A.J., Campbell, K.H., 1997. Viable offspring derived from fetal és adult mammalian cells. Nature 385, 810-813] described the successful application of almost exactly the same method, but using the nuclei of somatic cells from an adult mammal, to create Dolly the sheep. It has become theoretically possible to produce an unlimited number of genetic replicates from an adult animal or a post-implantation foetus. Since 1997 a number of different species including pigs, goats, horses, cats, etc. have been cloned with the somatic cell nuclear transfer technique. Although the technology still has relatively low success rates and there seems to be substantial problems with the welfare of some of the cloned animals, cloning is used both within basic research and the biomedical sector. The next step seems to be to implement cloning in the agricultural production system and several animals have been developed in this direction. This article reviews the current state of the art of farm animal cloning from a scientific and technological perspective, describes the animal welfare problems and critically assess different applications of farm animal cloning. The scope is confined to animal biotechnologies in which the use of cell nuclear transfer is an essential part and extends to both biomedical and agricultural applications of farm animal cloning. These applications include the production of genetically identical animals for research purposes, and also the creation of genetically modified animals. In the agricultural sector, cloning can be used as a tool within farm animal breeding. We do not intend to give an exhaustive review of the all the literature available; instead we pinpoint issues and events pivotal to the development of current farm animal cloning practices and their possible applications.

Engineering approaches to immunotherapy.

PubMed

Swartz, Melody A; Hirosue, Sachiko; Hubbell, Jeffrey A

2012-08-22

As the science of immunology grows increasingly mechanistic, motivation for developing quantitative, design-based engineering approaches has also evolved, both for therapeutic interventions and for elucidating immunological pathways in human disease. This has seeded the nascent field of "immunoengineering," which seeks to apply engineering analyses and design approaches to problems in translational immunology. For example, cell engineers are creating ways to tailor and use immune cells as living therapeutics; protein engineers are devising new methods of rapid antibody discovery; biomaterials scientists are guiding vaccine delivery and immune-cell activation with novel constructs; and systems immunologists are deciphering the evolution and maintenance of T and B cell receptor repertoires, which could help guide vaccine design. The field is multidisciplinary and collaborative, with engineers and immunologists working together to better understand and treat disease. We discuss the scientific progress in this young, yet rapidly evolving research area, which has yielded numerous start-up companies that are betting on impact in clinical and commercial translation in the near future.

Getting the current out

NASA Astrophysics Data System (ADS)

Burger, D. R.

1983-11-01

Progress of a photovoltaic (PV) device from a research concept to a competitive power-generation source requires an increasing concern with current collection. The initial metallization focus is usually on contact resistance, since a good ohmic contact is desirable for accurate device characterization measurements. As the device grows in size, sheet resistance losses become important and a metal grid is usually added to reduce the effective sheet resistance. Later, as size and conversion efficiency continue to increase, grid-line resistance and cell shadowing must be considered simultaneously, because grid-line resistance is inversely related to total grid-line area and cell shadowing is directly related. A PV cell grid design must consider the five power-loss phenomena mentioned above: sheet resistance, contact resistance, grid resistance, bus-bar resistance and cell shadowing. Although cost, reliability and usage are important factors in deciding upon the best metallization system, this paper will focus only upon grid-line design and substrate material problems for flat-plate solar arrays.

Attachment Anxiety is Linked to Alterations in Cortisol Production and Cellular Immunity

PubMed Central

Jaremka, Lisa M.; Glaser, Ronald; Loving, Timothy J.; Malarkey, William B.; Stowell, Jeffrey R.; Kiecolt-Glaser, Janice K.

2013-01-01

Although evidence suggests that attachment anxiety may increase risk for health problems, the mechanisms are not well understood. Married couples (N = 85, Mage = 38.67) provided saliva samples over three days and blood samples on two occasions. Participants with higher attachment anxiety produced more cortisol and had fewer numbers of CD3+ T-cells, CD45+ T-cells, CD3+CD4+ helper T-cells, and CD3+CD8+ cytotoxic T-cells than those with lower attachment anxiety. Higher cortisol was also related to fewer numbers of CD3+, CD45+, CD3+CD4+, and CD3+CD8+, which is mechanistically consistent with research showing that cortisol alters the cellular immune response. These data suggest that attachment anxiety may have physiological costs and provide a glimpse into the pathways through which social relationships impact health. The current study also extends attachment theory in an important new direction by utilizing a psychoneuroimmunological approach to the study of attachment anxiety, stress, and health. PMID:23307944

Engineering organs.

PubMed

Atala, Anthony

2009-10-01

Applications of regenerative medicine technology may offer novel therapies for patients with injuries, end-stage organ failure, or other clinical problems. Currently, patients suffering from diseased and injured organs can be treated with transplanted organs. However, there is a severe shortage of donor organs that is worsening yearly as the population ages and new cases of organ failure increase. Scientists in the field of regenerative medicine and tissue engineering are now applying the principles of cell transplantation, material science, and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. The stem cell field is also advancing rapidly, opening new avenues for this type of therapy. For example, therapeutic cloning and cellular reprogramming may one day provide a potentially limitless source of cells for tissue engineering applications. Although stem cells are still in the research phase, some therapies arising from tissue engineering endeavors have already entered the clinical setting successfully, indicating the promise regenerative medicine holds for the future.

A controlled double-duration inducible gene expression system for cartilage tissue engineering.

PubMed

Ma, Ying; Li, Junxiang; Yao, Yi; Wei, Daixu; Wang, Rui; Wu, Qiong

2016-05-25

Cartilage engineering that combines competent seeding cells and a compatible scaffold is increasingly gaining popularity and is potentially useful for the treatment of various bone and cartilage diseases. Intensive efforts have been made by researchers to improve the viability and functionality of seeding cells of engineered constructs that are implanted into damaged cartilage. Here, we designed an integrative system combining gene engineering and the controlled-release concept to solve the problems of both seeding cell viability and functionality through precisely regulating the anti-apoptotic gene bcl-2 in the short-term and the chondrogenic master regulator Sox9 in the long-term. Both in vitro and in vivo experiments demonstrated that our system enhances the cell viability and chondrogenic effects of the engineered scaffold after introduction of the system while restricting anti-apoptotic gene expression to only the early stage, thereby preventing potential oncogenic and overdose effects. Our system was designed to be modular and can also be readily adapted to other tissue engineering applications with minor modification.

Circulating Tumor Cells (CTCs): Emerging Technologies for Detection, Diagnosis and Treatment

NASA Astrophysics Data System (ADS)

McCarty, Owen

2010-03-01

Circulating tumor cell enumeration and characterization have the potential of providing real-time access to epithelial cancers in patients. This fluid phase biopsy of solid phase tumors is crucial to the development of quantitative diagnostic aiding personalized medicine. Cancer is a highly heterogeneous disease over space and time. Our goal is to generate a mechanistic, yet comprehensive view of both the `FORCE-journey' of a cancer cell during the metastatic phase, and a `TIME-journey' of the disease as it progresses. The approach will correlate the `FORCE' and `TIME' journey with both the bio-clinical aspects and the genomics of this complex problem. Presented will be results from a case study in lung cancer patients for which CTC analysis is compared with clinical progression. Morphologic and molecular characterization at the single cell level will be discussed in the context of the data set and in the context of individual patient management. Preliminary data will be shown to guide a future research agenda to investigate the fluid phase of solid tumors.

Patterned Cell Alignment in Response to Macroscale Curvature

NASA Astrophysics Data System (ADS)

Bade, Nathan; Kamien, Randall; Assoian, Richard; Stebe, Kathleen

The formation of spatial behavior patterns in tissues is a long-standing problem in biology. Decades of research have focused on understanding how biochemical signaling and morphogen gradients establish cell patterns during development and tissue morphogenesis. Here, we show that geometry and physical cues can drive organization and pattern formation. We find that mouse embryonic fibroblasts and human vascular smooth muscle cells sense curvature differently when in monolayers than when isolated on surfaces with various amounts of Gaussian curvature. While the long, apical stress fibers within these cells align in the direction of minimum curvature on cylindrical substrates, a subpopulation of stress fibers beneath the nucleus aligns in the circumferential direction and is bent maximally. We find dramatic reorganization of the actin cytoskeleton upon activation of RhoA, which is associated with increased contractility of the fibers. Thus, stress fiber alignment is likely a result of a complex balance between energy penalties associated with stress fiber bending, contractility, and the dynamics of F-actin assembly.

The Case for Absolute Ligand Discrimination: Modeling Information Processing and Decision by Immune T Cells

NASA Astrophysics Data System (ADS)

François, Paul; Altan-Bonnet, Grégoire

2016-03-01

Some cells have to take decision based on the quality of surroundings ligands, almost irrespective of their quantity, a problem we name "absolute discrimination". An example of absolute discrimination is recognition of not-self by immune T Cells. We show how the problem of absolute discrimination can be solved by a process called "adaptive sorting". We review several implementations of adaptive sorting, as well as its generic properties such as antagonism. We show how kinetic proofreading with negative feedback implement an approximate version of adaptive sorting in the immune context. Finally, we revisit the decision problem at the cell population level, showing how phenotypic variability and feedbacks between population and single cells are crucial for proper decision.

High-throughput proteomics : optical approaches.

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

Davidson, George S.

2008-09-01

Realistic cell models could greatly accelerate our ability to engineer biochemical pathways and the production of valuable organic products, which would be of great use in the development of biofuels, pharmaceuticals, and the crops for the next green revolution. However, this level of engineering will require a great deal more knowledge about the mechanisms of life than is currently available. In particular, we need to understand the interactome (which proteins interact) as it is situated in the three dimensional geometry of the cell (i.e., a situated interactome), and the regulation/dynamics of these interactions. Methods for optical proteomics have become availablemore » that allow the monitoring and even disruption/control of interacting proteins in living cells. Here, a range of these methods is reviewed with respect to their role in elucidating the interactome and the relevant spatial localizations. Development of these technologies and their integration into the core competencies of research organizations can position whole institutions and teams of researchers to lead in both the fundamental science and the engineering applications of cellular biology. That leadership could be particularly important with respect to problems of national urgency centered around security, biofuels, and healthcare.« less

Food-Induced Acute Pancreatitis.

PubMed

Manohar, Murli; Verma, Alok K; Upparahalli Venkateshaiah, Sathisha; Goyal, Hemant; Mishra, Anil

2017-12-01

Food allergy, a commonly increasing problem worldwide, defined as an adverse immune response to food. A variety of immune-related effector cells such as mast cells, eosinophils, neutrophils, and T cells are involved in food-related allergic responses categorized as IgE mediated, non-IgE mediated, and mixed (IgE and non-IgE) depending upon underlying immunological mechanisms. The dietary antigens mainly target the gastrointestinal tract including pancreas that gets inflamed due to food allergy and leads acute pancreatitis. Reports indicate several food proteins induce pancreatitis; however, detailed underlying mechanism of food-induced pancreatitis is unexplored. The aim of the review is to understand and update the current scenario of food-induced pancreatitis. A comprehensive literature search of relevant research articles has been performed through PubMed, and articles were chosen based on their relevance to food allergen-mediated pancreatitis. Several cases in the literature indicate that acute pancreatitis has been provoked after the consumption of mustard, milk, egg, banana, fish, and kiwi fruits. Food-induced pancreatitis is an ignored and unexplored area of research. The review highlights the significance of food in the development of pancreatitis and draws the attention of physicians and scientists to consider food allergies as a possible cause for initiation of pancreatitis pathogenesis.

Cognitive hypnotherapy for pain management.

PubMed

Elkins, Gary; Johnson, Aimee; Fisher, William

2012-04-01

Pain is a serious health care problem and there is growing evidence to support the use of hypnosis and cognitive-behavioral interventions for pain management. This article reviews clinical techniques and methods of cognitive hypnotherapy for pain management. Current research with emphasis given to randomized, controlled trials is presented and the efficacy of hypnotherapy for pain management is discussed. Evidence for cognitive hypnotherapy in the treatment in chronic pain, cancer, osteoarthritis, sickle cell disease, temporomandibular disorder, fibromyalgia, non-cardiac chest pain, and disability related chronic pains are identified. Implications for clinical practice and research are discussed in light of the accumulating evidence in support of the efficacy and effectiveness of cognitive hypnotherapy for pain management.

Life sciences and environmental sciences

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

Not Available

1992-02-01

The DOE laboratories play a unique role in bringing multidisciplinary talents -- in biology, physics, chemistry, computer sciences, and engineering -- to bear on major problems in the life and environmental sciences. Specifically, the laboratories utilize these talents to fulfill OHER's mission of exploring and mitigating the health and environmental effects of energy use, and of developing health and medical applications of nuclear energy-related phenomena. At Lawrence Berkeley Laboratory (LBL) support of this mission is evident across the spectrum of OHER-sponsored research, especially in the broad areas of genomics, structural biology, basic cell and molecular biology, carcinogenesis, energy and environment,more » applications to biotechnology, and molecular, nuclear and radiation medicine. These research areas are briefly described.« less

The quest for a new modelling framework in mathematical biology. Comment on "On the interplay between mathematics and biology: Hallmarks towards a new systems biology" by N. Bellomo et al.

NASA Astrophysics Data System (ADS)

Eftimie, Raluca

2015-03-01

One of the main unsolved problems of modern physics is finding a "theory of everything" - a theory that can explain, with the help of mathematics, all physical aspects of the universe. While the laws of physics could explain some aspects of the biology of living systems (e.g., the phenomenological interpretation of movement of cells and animals), there are other aspects specific to biology that cannot be captured by physics models. For example, it is generally accepted that the evolution of a cell-based system is influenced by the activation state of cells (e.g., only activated and functional immune cells can fight diseases); on the other hand, the evolution of an animal-based system can be influenced by the psychological state (e.g., distress) of animals. Therefore, the last 10-20 years have seen also a quest for a "theory of everything"-approach extended to biology, with researchers trying to propose mathematical modelling frameworks that can explain various biological phenomena ranging from ecology to developmental biology and medicine [1,2,6]. The basic idea behind this approach can be found in a few reviews on ecology and cell biology [6,7,9-11], where researchers suggested that due to the parallel between the micro-scale dynamics and the emerging macro-scale phenomena in both cell biology and in ecology, many mathematical methods used for ecological processes could be adapted to cancer modelling [7,9] or to modelling in immunology [11]. However, this approach generally involved the use of different models to describe different biological aspects (e.g., models for cell and animal movement, models for competition between cells or animals, etc.).

Unresolved issues in mammalian fertilization.

PubMed

Olds-Clarke, Patricia

2003-01-01

This review considers the role of the sperm in fertilization, addressing areas of misunderstanding and unfounded assumptions and taking particular advantage of the large body of data resulting from work with rodent species in vitro. Considerable attention is given to the appropriate use and interpretation of assays for capacitation, acrosomal exocytosis, hyperactivation, and sperm protein phosphorylation, as well as tests for sperm-zona and sperm-oocyte membrane interactions. The lack of general agreement on the means of sperm adhesion to and penetration of the zona pellucida is addressed, and the need for new approaches to this problem is pointed out. Some molecular advances in our understanding of specific steps in the process of fertilization are discussed in the context of intact cell-matrix and cell-cell interaction. This review should provide practical information for researchers just beginning the study of fertilization and interesting but not widely known observations to stimulate new ideas in experienced scientists.

Cell proliferation assessment in oncology.

PubMed

Hofstädter, F; Knüchel, R; Rüschoff, J

1995-01-01

A review of the current knowledge on cell cycle control and the techniques used to assess proliferation of normal and neoplastic cells was the focus of a workshop in Regensburg, Germany, held under the joint auspices of the Graduiertenkolleg: Therapieforschung Onkologie and the Committee on AgNOR Quantification. An overview of the recently discovered group of cyclins and their specific kinases, and of other proliferation-associated antigens, such as Ki67, PCNA and topoiseromase II alpha, was given. The topics continued with a reappraisal of modern imaging and flow-cytometric techniques. An update of the relation of AgNORs to cellular proliferation and differentiation was the link to presentations on clinical data, problems and strategies for standardization, as well as guidelines to establish the prognostic value of marker molecules. These lectures were supported by posters. Bringing together researchers from life sciences, technically oriented workers, pathologists, and clinicians resulted in a lively and constructive discussion, which is briefly summarized in the Concluding remarks.

A study of upwind schemes on the laminar hypersonic heating predictions for the reusable space vehicle

NASA Astrophysics Data System (ADS)

Qu, Feng; Sun, Di; Zuo, Guang

2018-06-01

With the rapid development of the Computational Fluid Dynamics (CFD), Accurate computing hypersonic heating is in a high demand for the design of the new generation reusable space vehicle to conduct deep space exploration. In the past years, most researchers try to solve this problem by concentrating on the choice of the upwind schemes or the definition of the cell Reynolds number. However, the cell Reynolds number dependencies and limiter dependencies of the upwind schemes, which are of great importance to their performances in hypersonic heating computations, are concerned by few people. In this paper, we conduct a systematic study on these properties respectively. Results in our test cases show that SLAU (Simple Low-dissipation AUSM-family) is with a much higher level of accuracy and robustness in hypersonic heating predictions. Also, it performs much better in terms of the limiter dependency and the cell Reynolds number dependency.

State participation in the creation of fuel-cell-based power plants to meet civilian demand in Russia

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

Pekhota, F.N.

1996-04-01

At present, up to 70% of Russian territory is not covered by central electrical distribution systems. In the field of fuel cell power plants, Russia is at parity with the leading foreign countries with respect to both technical and economic performance and the level of research being conducted. Civilian use of these generating systems on a broad scale, however, demands that a number of problems be solved, particularly those relating to the need for longer plant service life, lower unit cost of electricity, etc. The Ministry of Science and technical Policy of the Russian Federation issued a decree creating amore » new are of concentration, `Fuel Cell Based Power Plants for Civilian Needs,` in the GNTPR `Environmentally Clean Power Industry,` which will form the basis for financial support in this area out of the federal budget.« less

Atmospheric-Pressure-Spray, Chemical- Vapor-Deposited Thin-Film Materials Being Developed for High Power-to- Weight-Ratio Space Photovoltaic Applications

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; Harris, Jerry D.; Raffaelle, Ryne P.; Banger, Kulbinder K.; Smith, Mark A.; Cowen, Jonathan E.

2001-01-01

The key to achieving high specific power (watts per kilogram) space photovoltaic arrays is the development of high-efficiency thin-film solar cells that are fabricated on lightweight, space-qualified substrates such as Kapton (DuPont) or another polymer film. Cell efficiencies of 20 percent air mass zero (AM0) are required. One of the major obstacles to developing lightweight, flexible, thin-film solar cells is the unavailability of lightweight substrate or superstrate materials that are compatible with current deposition techniques. There are two solutions for working around this problem: (1) develop new substrate or superstrate materials that are compatible with current deposition techniques, or (2) develop new deposition techniques that are compatible with existing materials. The NASA Glenn Research Center has been focusing on the latter approach and has been developing a deposition technique for depositing thin-film absorbers at temperatures below 400 C.

Nanomedicine: Techniques, Potentials, and Ethical Implications

PubMed Central

Ebbesen, Mette; Jensen, Thomas G.

2006-01-01

Nanotechnology is concerned with materials and systems whose structures and components exhibit novel physical, chemical, and biological properties due to their nanoscale size. This paper focuses on what is known as nanomedicine, referring to the application of nanotechnology to medicine. We consider the use and potentials of emerging nanoscience techniques in medicine such as nanosurgery, tissue engineering, and targeted drug delivery, and we discuss the ethical questions that these techniques raise. The ethical considerations involved in nanomedicine are related to risk assessment in general, somatic-cell versus germline-cell therapy, the enhancement of human capabilities, research into human embryonic stem cells and the toxicity, uncontrolled function and self-assembly of nanoparticles. The ethical considerations associated with the application of nanotechnology to medicine have not been greatly discussed. This paper aims to balance clear ethical discussion and sound science and so provide nanotechnologists and biotechnologists with tools to assess ethical problems in nanomedicine. PMID:17489016

Advances in combining gene therapy with cell and tissue engineering-based approaches to enhance healing of the meniscus.

PubMed

Cucchiarini, M; McNulty, A L; Mauck, R L; Setton, L A; Guilak, F; Madry, H

2016-08-01

Meniscal lesions are common problems in orthopaedic surgery and sports medicine, and injury or loss of the meniscus accelerates the onset of knee osteoarthritis (OA). Despite a variety of therapeutic options in the clinics, there is a critical need for improved treatments to enhance meniscal repair. In this regard, combining gene-, cell-, and tissue engineering-based approaches is an attractive strategy to generate novel, effective therapies to treat meniscal lesions. In the present work, we provide an overview of the tools currently available to improve meniscal repair and discuss the progress and remaining challenges for potential future translation in patients. Copyright © 2016 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Transient thermal state of an active Braille matrix with incorporated thermal actuators by means of finite element method.

PubMed

Aluţei, Alexandra-Maria; Szelitzky, Emoke; Mândru, Dan

2013-01-01

In this article the authors present the transient thermal analysis for a developed thermal linear actuator based on wax paraffin used to drive the cells of a Braille device. A numerical investigation of transient heat transfer phenomenon during paraffin melting and solidification in an encapsulated recipient has been carried out using the ANSYS v.12 software. The researchers offer data on the heat distribution in the proposed model of the actuator as well as on the material properties required for these applications and provide the opportunity to identify new problems specific to thermal actuation, such as the heater properties and the cooling process of the active material in the structure of the Braille cell.

Hydrodynamic Contributions to Amoeboid Cell Motility

NASA Astrophysics Data System (ADS)

Lewis, Owen; Guy, Robert

2011-11-01

Understanding the methods by which cells move is a fundamental problem in modern biology. Recent evidence has shown that the fluid dynamics of cytoplasm can play a vital role in cellular motility. The slime mold Physarum polycephalum provides an excellent model organism for the study of amoeboid motion. In this research, we use both analytic and computational models to investigate intracellular fluid flow in a simple model of Physarum. In both models, of we are specifically interested in stresses generated by cytoplasmic flow which act in the direction of cellular motility. In our numerical model, the Immersed Boundary Method is used to account for such stresses. We investigate the relationship between contraction waves, low waves and locomotive forces, and attempt characterize conditions necessary to generate directed motion.

"Discovering the Cell": An Educational Game about Cell and Molecular Biology

ERIC Educational Resources Information Center

Spiegel, Carolina N.; Alves, Gutemberg G.; Cardona, Tania da S.; Melim, Leandra M. C.; Luz, Mauricio R. M. P.; Araujo-Jorge, Tania C.; Henriques-Pons, Andrea

2008-01-01

The role of games within education becomes clearer as students become more active and are able to take decisions, solve problems and react to the results of those decisions. The educational board game "Discovering the Cell" ("Celula Adentro"), is based on problem-solving learning. This investigative game attempts to stimulate…

Representations of stem cell clinics on Twitter.

PubMed

Kamenova, Kalina; Reshef, Amir; Caulfield, Timothy

2014-12-01

The practice of travelling abroad to receive unproven and unregulated stem cell treatments has become an increasingly problematic global phenomenon known as 'stem cell tourism'. In this paper, we examine representations of nine major clinics and providers of such treatments on the microblogging network Twitter. We collected and conducted a content analysis of Twitter posts (n = 363) by these establishments and by other users mentioning them, focusing specifically on marketing claims about treatment procedures and outcomes, discussions of safety and efficacy of stem cell transplants, and specific representations of patients' experiences. Our analysis has shown that there were explicit claims or suggestions of benefits associated with unproven stem cell treatments in approximately one third of the tweets and that patients' experiences, whenever referenced, were presented as invariably positive and as testimonials about the efficacy of stem cell transplants. Furthermore, the results indicated that the tone of most tweets (60.2 %) was overwhelmingly positive and there were rarely critical discussions about significant health risks associated with unproven stem cell therapies. When placed in the context of past research on the problems associated with the marketing of unproven stem cell therapies, this analysis of representations on Twitter suggests that discussions in social media have also remained largely uncritical of the stem cell tourism phenomenon, with inaccurate representations of risks and benefits for patients.

Role of Child and Maternal Processes in the Psychological Adjustment of Children with Sickle Cell Disease.

ERIC Educational Resources Information Center

Thompson, Robert J., Jr.; And Others

1993-01-01

Found that 64% of 50 children aged 7-12 years with sickle cell disease had parent-reported behavior problem. Internalizing types of behavior problems and diagnoses were most frequent. Maternal anxiety accounted for 16-33% of variance in mother-reported internalizing and externalizing behavior problems, respectively, and child pain-coping…

Disciplinary Foundations for Solving Interdisciplinary Scientific Problems

ERIC Educational Resources Information Center

Zhang, Dongmei; Shen, Ji

2015-01-01

Problem-solving has been one of the major strands in science education research. But much of the problem-solving research has been conducted on discipline-based contexts; little research has been done on how students, especially individuals, solve interdisciplinary problems. To understand how individuals reason about interdisciplinary problems, we…

[Analysis on research projects for acupuncture and moxibustion supported by NSFC during the 11th 5-year-plan].

PubMed

Zhao, Chang-Long; Jing, Xiang-Hong; Li, Yu-Qing; Li, Liang; Rong, Pei-Jing; Wang, Chang-En

2012-08-01

In the present paper, the authors introduce the approved and finished research projects for acupuncture and moxibustion therapies supported by the National Natural Science Foundation of China (NSFC) during the 11th 5-year-plan. A total of 194 research projects were subsidized by NSFC from 2006 to 2010. These projects include 6 aspects: meridian-collaterals, acupoint theory, acupuncture analgesia, mechanisms underlying improvement of different clinical problems, clinical trials, and moxibustion therapy. The research on acupoints has been becoming a new hotspot in recent years. Majority of the research projects focus on the mechanism of acu-moxibustion underlying improvement of different clinical problems, while fewer projects on clinical trials. During the 11th 5-year-plan, 119 projects were completed; most of them involved meridian-collateral theory, acupoint theory, mechanism of acu-moxibustion underlying improvement of clinical problems and acupuncture manipulations. Following analysis of the finished research projects, we find that 1) many neurobiological methods and techniques are commonly used in the research on meridian-collateral theory; 2) the research on acupoint theory is changing from observing the local morphological structure to identifying characteristics of the regional activated receptors, particularly under the circumstances of visceral pathological conditions and efficacies of acupoints; 3) researches on the underlying mechanism of acu-moxibusiton for improving clinical disorders mainly focused on its cerebral protective effects against cerebral ischemia, in addition, researches about other diseases on clinical conditions have been also carried out, but the related mechanisms are far from understanding; 4) In many research projects, various new methods and techniques, such as fMRI, position emission tomography, genomics, proteomics, molecular biology, nerve stem cell, etc. were widely used; 5) Randomized controlled multi-center clinical trials are definitely insufficient. Only two clinical projects were finished during the 11th 5-year-plan. Moreover, it should be noted that in the subject of acu-moxibustion, independent innovation researches are fewer; the foundation of competitive ability is relatively weaker; the supporting conditions for finishing the research projects are poorer in some institutes or districts; and the interrelations among the theoretical, experimental and clinical researches are not intimately close, leading to relative lag in the subject development.

Highly efficient targeted mutagenesis in one-cell mouse embryos mediated by the TALEN and CRISPR/Cas systems.

PubMed

Yasue, Akihiro; Mitsui, Silvia Naomi; Watanabe, Takahito; Sakuma, Tetsushi; Oyadomari, Seiichi; Yamamoto, Takashi; Noji, Sumihare; Mito, Taro; Tanaka, Eiji

2014-07-16

Since the establishment of embryonic stem (ES) cell lines, the combined use of gene targeting with homologous recombination has aided in elucidating the functions of various genes. However, the ES cell technique is inefficient and time-consuming. Recently, two new gene-targeting technologies have been developed: the transcription activator-like effector nuclease (TALEN) system, and the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas) system. In addition to aiding researchers in solving conventional problems, these technologies can be used to induce site-specific mutations in various species for which ES cells have not been established. Here, by targeting the Fgf10 gene through RNA microinjection in one-cell mouse embryos with the TALEN and CRISPR/Cas systems, we produced the known limb-defect phenotypes of Fgf10-deficient embryos at the F0 generation. Compared to the TALEN system, the CRISPR/Cas system induced the limb-defect phenotypes with a strikingly higher efficiency. Our results demonstrate that although both gene-targeting technologies are useful, the CRISPR/Cas system more effectively elicits single-step biallelic mutations in mice.

A novel cobalt-free layered GdBaFe 2O 5+ δ cathode for proton conducting solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Ding, Hanping; Xue, Xingjian

While cobalt-containing perovskite-type cathode materials facilitate the activation of oxygen reduction, they also suffer from problems like poor chemical stability in CO 2 and high thermal expansion coefficients. In this research, a cobalt-free layered GdBaFe 2O 5+ δ (GBF) perovskite was developed as a cathode material for protonic ceramic membrane fuel cells (PCMFCs) based on proton conducting electrolyte of stable BaZr 0.1Ce 0.7Y 0.2O 3- δ (BZCY7). The button cells of Ni-BZCY7|BZCY7|GBF were fabricated and characterized using complex impedance technique from 600 to 700 °C. An open-circuit potential of 1.007 V, maximum power density of 417 mW cm -2, and a low electrode polarization resistance of 0.18 Ω cm 2 were achieved at 700 °C. The results indicate that layered GBF perovskite is a good candidate for cobalt-free cathode material, while the developed Ni-BZCY7|BZCY7|GBF cell is a promising functional material system for solid oxide fuel cells.

Automated Ki-67 Quantification of Immunohistochemical Staining Image of Human Nasopharyngeal Carcinoma Xenografts.

PubMed

Shi, Peng; Zhong, Jing; Hong, Jinsheng; Huang, Rongfang; Wang, Kaijun; Chen, Yunbin

2016-08-26

Nasopharyngeal carcinoma is one of the malignant neoplasm with high incidence in China and south-east Asia. Ki-67 protein is strictly associated with cell proliferation and malignant degree. Cells with higher Ki-67 expression are always sensitive to chemotherapy and radiotherapy, the assessment of which is beneficial to NPC treatment. It is still challenging to automatically analyze immunohistochemical Ki-67 staining nasopharyngeal carcinoma images due to the uneven color distributions in different cell types. In order to solve the problem, an automated image processing pipeline based on clustering of local correlation features is proposed in this paper. Unlike traditional morphology-based methods, our algorithm segments cells by classifying image pixels on the basis of local pixel correlations from particularly selected color spaces, then characterizes cells with a set of grading criteria for the reference of pathological analysis. Experimental results showed high accuracy and robustness in nucleus segmentation despite image data variance. Quantitative indicators obtained in this essay provide a reliable evidence for the analysis of Ki-67 staining nasopharyngeal carcinoma microscopic images, which would be helpful in relevant histopathological researches.

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.

Numerical algebraic geometry for model selection and its application to the life sciences

PubMed Central

Gross, Elizabeth; Davis, Brent; Ho, Kenneth L.; Bates, Daniel J.

2016-01-01

Researchers working with mathematical models are often confronted by the related problems of parameter estimation, model validation and model selection. These are all optimization problems, well known to be challenging due to nonlinearity, non-convexity and multiple local optima. Furthermore, the challenges are compounded when only partial data are available. Here, we consider polynomial models (e.g. mass-action chemical reaction networks at steady state) and describe a framework for their analysis based on optimization using numerical algebraic geometry. Specifically, we use probability-one polynomial homotopy continuation methods to compute all critical points of the objective function, then filter to recover the global optima. Our approach exploits the geometrical structures relating models and data, and we demonstrate its utility on examples from cell signalling, synthetic biology and epidemiology. PMID:27733697

How can we improve problem solving in undergraduate biology? Applying lessons from 30 years of physics education research.

PubMed

Hoskinson, A-M; Caballero, M D; Knight, J K

2013-06-01

If students are to successfully grapple with authentic, complex biological problems as scientists and citizens, they need practice solving such problems during their undergraduate years. Physics education researchers have investigated student problem solving for the past three decades. Although physics and biology problems differ in structure and content, the instructional purposes align closely: explaining patterns and processes in the natural world and making predictions about physical and biological systems. In this paper, we discuss how research-supported approaches developed by physics education researchers can be adopted by biologists to enhance student problem-solving skills. First, we compare the problems that biology students are typically asked to solve with authentic, complex problems. We then describe the development of research-validated physics curricula emphasizing process skills in problem solving. We show that solving authentic, complex biology problems requires many of the same skills that practicing physicists and biologists use in representing problems, seeking relationships, making predictions, and verifying or checking solutions. We assert that acquiring these skills can help biology students become competent problem solvers. Finally, we propose how biology scholars can apply lessons from physics education in their classrooms and inspire new studies in biology education research.

Application of tabu search to deterministic and stochastic optimization problems

NASA Astrophysics Data System (ADS)

Gurtuna, Ozgur

During the past two decades, advances in computer science and operations research have resulted in many new optimization methods for tackling complex decision-making problems. One such method, tabu search, forms the basis of this thesis. Tabu search is a very versatile optimization heuristic that can be used for solving many different types of optimization problems. Another research area, real options, has also gained considerable momentum during the last two decades. Real options analysis is emerging as a robust and powerful method for tackling decision-making problems under uncertainty. Although the theoretical foundations of real options are well-established and significant progress has been made in the theory side, applications are lagging behind. A strong emphasis on practical applications and a multidisciplinary approach form the basic rationale of this thesis. The fundamental concepts and ideas behind tabu search and real options are investigated in order to provide a concise overview of the theory supporting both of these two fields. This theoretical overview feeds into the design and development of algorithms that are used to solve three different problems. The first problem examined is a deterministic one: finding the optimal servicing tours that minimize energy and/or duration of missions for servicing satellites around Earth's orbit. Due to the nature of the space environment, this problem is modeled as a time-dependent, moving-target optimization problem. Two solution methods are developed: an exhaustive method for smaller problem instances, and a method based on tabu search for larger ones. The second and third problems are related to decision-making under uncertainty. In the second problem, tabu search and real options are investigated together within the context of a stochastic optimization problem: option valuation. By merging tabu search and Monte Carlo simulation, a new method for studying options, Tabu Search Monte Carlo (TSMC) method, is developed. The theoretical underpinnings of the TSMC method and the flow of the algorithm are explained. Its performance is compared to other existing methods for financial option valuation. In the third, and final, problem, TSMC method is used to determine the conditions of feasibility for hybrid electric vehicles and fuel cell vehicles. There are many uncertainties related to the technologies and markets associated with new generation passenger vehicles. These uncertainties are analyzed in order to determine the conditions in which new generation vehicles can compete with established technologies.

Oversight of human participants research: identifying problems to evaluate reform proposals.

PubMed

Emanuel, Ezekiel J; Wood, Anne; Fleischman, Alan; Bowen, Angela; Getz, Kenneth A; Grady, Christine; Levine, Carol; Hammerschmidt, Dale E; Faden, Ruth; Eckenwiler, Lisa; Muse, Carianne Tucker; Sugarman, Jeremy

2004-08-17

The oversight of research involving human participants is widely believed to be inadequate. The U.S. Congress, national commissions, the Department of Health and Human Services, the Institute of Medicine, numerous professional societies, and others are proposing remedies based on the assumption that the main problems are researchers' conflict of interest, lack of institutional review board (IRB) resources, and the volume and complexity of clinical research. Developing appropriate reform proposals requires carefully delineating the problems of the current system to know what reforms are needed. To stimulate a more informed and meaningful debate, we delineate 15 current problems into 3 broad categories. First, structural problems encompass 8 specific problems related to the way the research oversight system is organized. Second, procedural problems constitute 5 specific problems related to the operations of IRB review. Finally, performance assessment problems include 2 problems related to absence of systematic assessment of the outcomes of the oversight system. We critically assess proposed reforms, such as accreditation and central IRBs, according to how well they address these 15 problems. None of the reforms addresses all 15 problems. Indeed, most focus on the procedural problems, failing to address either the structure or the performance assessment problems. Finally, on the basis of the delineation of problems, we outline components of a more effective reform proposal, including bringing all research under federal oversight, a permanent advisory committee to address recurrent ethical issues in clinical research, mandatory single-time review for multicenter research protocols, additional financial support for IRB functions, and a standardized system for collecting and disseminating data on both adverse events and the performance assessment of IRBs.

Tackling bioactive glass excessive in vitro bioreactivity: Preconditioning approaches for cell culture tests.

PubMed

Ciraldo, Francesca E; Boccardi, Elena; Melli, Virginia; Westhauser, Fabian; Boccaccini, Aldo R

2018-05-21

Bioactive glasses (BGs) are being increasingly considered for biomedical applications in bone and soft tissue replacement approaches thanks to their ability to form strong bonding with tissues. However, due to their high reactivity once in contact with water-based solutions BGs rapidly exchange ions with the surrounding environment leading in most cases to an undesired increase of the pH under static in vitro conditions (due to alkaline ion "burst release"), making difficult or even impossible to perform cell culture studies. Several pre-conditioning treatments have been therefore proposed in laboratories worldwide to limit this problem. This paper presents an overview of the different strategies that have been put forward to pre-treat BG samples to tackle the pH raise issue in order to enable cell biology studies. The paper also discusses the relevant criteria that determine the selection of the optimal pre-treatment depending on the BG composition and morphology (e.g. particles, scaffolds). Bioactive glasses (BGs), since their discovery in 1971 by L.L Hench, have been widely used for bone replacement and repair, and, more recently, they are becoming highly attractive for bone and soft tissue engineering applications. BGs have in fact the ability to form a strong bond with both hard and soft tissues once in contact with biological fluid. The enhanced interaction of BGs with the biological environment is based on their significant surface bioreactivity. This surface effect of BGs is, on the other hand, problematic for cell biology studies by standard (static) cell culture methods: an excessive bioreactivity leads in most cases to a rapid and dramatic increase of the pH of the surrounding medium, which results in cell death and makes cell culture tests on BG samples impossible. The BG research community has been aware of this for many years and numerous pre-treatments have been proposed by different groups worldwide to limit this problem. For the first time, we have reviewed in this paper the variety of surface preconditioning treatments that have been put forward over the years, we provide a summary of such pre-treatments used in laboratory practice, discussing and offering criteria that can be used for the determination of the optimal pre-treatment depending on BG composition and morphology of the sample tested (bulk, particulate, scaffolds). The information and discussion provided in this review should support best research practice when testing bioactive glasses in cell culture. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

"Comments on Bulterman-Bos": Education Research as a Distributed Activity across Universities

ERIC Educational Resources Information Center

Lagemann, Ellen Condliffe

2008-01-01

In response to Bulterman-Bos (2008), this article discusses three kinds of research needed in education: problem-finding research, which helps frame good research questions; problem-solving research, which helps illuminate educational problems; and translational work, which transforms the findings of research into tools that practitioners and…

A study of alternative designs for a system to concentrate carbon dioxide in a hydrogen-depolarized cell

NASA Technical Reports Server (NTRS)

1973-01-01

Experimental results are presented on alternative designs for a hydrogen depolarized cell to concentrate CO2 in spacecraft atmospheric control systems. Data cover technical problems, methods for solving these problems, and the suitability of such a cell for CO2 removal and control of atmospheric humidity during the flight mode.

[Strategies and mechanisms of soil springtails in adapting lower temperature environment: research progress].

PubMed

Liu, Jing; Wang, Yun-Biao; Wu, Dong-Hui

2012-12-01

Low temperature and drought are the main environmental factors threatening the animals living in arctic area and cold temperate regions. To adapt the severe environment, the animals should adopt appropriate strategies. As a group of arthopods with freeze-avoiding strategy, soil springtails have the similar ecological mechanisms and modes of cold resistance/tolerance as insects, manifesting in the cold acclimation and drought tolerance to decrease the damage of ice crystal formation. During cold acclimation, there are a rapid increase of glycerol, a rapid decrease of fucose and glucose, and the production of anti-freeze proteins (AFP) , and exists the inter-transformation of different kinds of lipids to improve the flow of cell membrane to protect the cell from low temperature injury. In addition, soil springtails have their own specific modes and mechanisms to tolerate low temperature stress, mainly the vertical migration under the protection of snow cover and the excretion of ice nucleator from haemolymph, illustrating that it's of significance to research the cryobiology of soil springtails. This paper summarized the modes and mechanisms of soil springtails in tolerating low temperature environment, reviewed the research progress on the eco-physiology of the springtails, discussed the existing problems of the researches on the low temperature tolerance of the springtails, and prospected the research directions of the springtails low temperature ecology under the background of global change.

Academic and molecular matrices: A study of the transformations of connective tissue research at the University of Manchester (1947–1996)☆

PubMed Central

García-Sancho, Miguel

2011-01-01

This paper explores the different identities adopted by connective tissue research at the University of Manchester during the second half of the 20th century. By looking at the long-term redefinition of a research programme, it sheds new light on the interactions between different and conflicting levels in the study of biomedicine, such as the local and the global, or the medical and the biological. It also addresses the gap in the literature between the first biomedical complexes after World War II and the emergence of biotechnology. Connective tissue research in Manchester emerged as a field focused on new treatments for rheumatic diseases. During the 1950s and 60s, it absorbed a number of laboratory techniques from biology, namely cell culture and electron microscopy. The transformations in scientific policy during the late 70s and the migration of Manchester researchers to the US led them to adopt recombinant DNA methods, which were borrowed from human genetics. This resulted in the emergence of cell matrix biology, a new field which had one of its reference centres in Manchester. The Manchester story shows the potential of detailed and chronologically wide local studies of patterns of work to understand the mechanisms by which new biomedical tools and institutions interact with long-standing problems and existing affiliations. PMID:21486662

Imaging Transcriptional Regulation of Eukaryotic mRNA Genes: Advances and Outlook.

PubMed

Yao, Jie

2017-01-06

Regulation of eukaryotic transcription in vivo occurs at distinct stages. Previous research has identified many active or repressive transcription factors (TFs) and core transcription components and studied their functions in vitro and in vivo. Nonetheless, how individual TFs act in concert to regulate mRNA gene expression in a single cell remains poorly understood. Direct observation of TF assembly and disassembly and various biochemical reactions during transcription of a single-copy gene in vivo is the ideal approach to study this problem. Research in this area requires developing novel techniques for single-cell transcription imaging and integrating imaging studies into understanding the molecular biology of transcription. In the past decade, advanced cell imaging has enabled unprecedented capabilities to visualize individual TF molecules, to track single transcription sites, and to detect individual mRNA in fixed and living cells. These studies have raised several novel insights on transcriptional regulation such as the "hit-and-run" model and transcription bursting that could not be obtained by in vitro biochemistry analysis. At this point, the key question is how to achieve deeper understandings or discover novel mechanisms of eukaryotic transcriptional regulation by imaging transcription in single cells. Meanwhile, further technical advancements are likely required for visualizing distinct kinetic steps of transcription on a single-copy gene in vivo. This review article summarizes recent progress in the field and describes the challenges and opportunities ahead. Copyright © 2016 Elsevier Ltd. All rights reserved.

Bioreactors Drive Advances in Tissue Engineering

NASA Technical Reports Server (NTRS)

2012-01-01

It was an unlikely moment for inspiration. Engineers David Wolf and Ray Schwarz stopped by their lab around midday. Wolf, of Johnson Space Center, and Schwarz, with NASA contractor Krug Life Sciences (now Wyle Laboratories Inc.), were part of a team tasked with developing a unique technology with the potential to enhance medical research. But that wasn t the focus at the moment: The pair was rounding up colleagues interested in grabbing some lunch. One of the lab s other Krug engineers, Tinh Trinh, was doing something that made Wolf forget about food. Trinh was toying with an electric drill. He had stuck the barrel of a syringe on the bit; it spun with a high-pitched whirr when he squeezed the drill s trigger. At the time, a multidisciplinary team of engineers and biologists including Wolf, Schwarz, Trinh, and project manager Charles D. Anderson, who formerly led the recovery of the Apollo capsules after splashdown and now worked for Krug was pursuing the development of a technology called a bioreactor, a cylindrical device used to culture human cells. The team s immediate goal was to grow human kidney cells to produce erythropoietin, a hormone that regulates red blood cell production and can be used to treat anemia. But there was a major barrier to the technology s success: Moving the liquid growth media to keep it from stagnating resulted in turbulent conditions that damaged the delicate cells, causing them to quickly die. The team was looking forward to testing the bioreactor in space, hoping the device would perform more effectively in microgravity. But on January 28, 1986, the Space Shuttle Challenger broke apart shortly after launch, killing its seven crewmembers. The subsequent grounding of the shuttle fleet had left researchers with no access to space, and thus no way to study the effects of microgravity on human cells. As Wolf looked from Trinh s syringe-capped drill to where the bioreactor sat on a workbench, he suddenly saw a possible solution to both problems. It dawned on me that rotating the wall of the reactor would solve one of our fundamental fluid mechanical problems, specifically by removing the velocity gradient of the tissue culture fluid media near the reactor s walls, says Wolf. It looked as though it would allow us to suspend the growing cells within the reactor without introducing turbulent fluid mechanical conditions.

Advanced chemical hydride-based hydrogen generation/storage system for fuel cell vehicles

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

Breault, R.W.; Rolfe, J.

1998-08-01

Because of the inherent advantages of high efficiency, environmental acceptability, and high modularity, fuel cells are potentially attractive power supplies. Worldwide concerns over clean environments have revitalized research efforts on developing fuel cell vehicles (FCV). As a result of intensive research efforts, most of the subsystem technology for FCV`s are currently well established. These include: high power density PEM fuel cells, control systems, thermal management technology, and secondary power sources for hybrid operation. For mobile applications, however, supply of hydrogen or fuel for fuel cell operation poses a significant logistic problem. To supply high purity hydrogen for FCV operation, Thermomore » Power`s Advanced Technology Group is developing an advanced hydrogen storage technology. In this approach, a metal hydride/organic slurry is used as the hydrogen carrier and storage media. At the point of use, high purity hydrogen will be produced by reacting the metal hydride/organic slurry with water. In addition, Thermo Power has conceived the paths for recovery and regeneration of the spent hydride (practically metal hydroxide). The fluid-like nature of the spent hydride/organic slurry will provide a unique opportunity for pumping, transporting, and storing these materials. The final product of the program will be a user-friendly and relatively high energy storage density hydrogen supply system for fuel cell operation. In addition, the spent hydride can relatively easily be collected at the pumping station and regenerated utilizing renewable sources, such as biomass, natural, or coal, at the central processing plants. Therefore, the entire process will be economically favorable and environmentally friendly.« less

Disturb-Free Three-Dimensional Vertical Floating Gate NAND with Separated-Sidewall Control Gate

NASA Astrophysics Data System (ADS)

Seo, Moon-Sik; Endoh, Tetsuo

2012-02-01

Recently, the three-dimensional (3D) vertical floating gate (FG) type NAND cell arrays with the sidewall control gate (SCG) structure are receiving attention to overcome the reliability issues of charge trap (CT) type 3D NAND. In order to achieve the multilevel cell (MLC) operation for lower bit cost in 3D NAND, it is important to eliminate reliability issues, such as the Vth distribution with interference and disturbance problems and Vth shift with retention issues. In this paper, we intensively investigated the disturbance problems of the 3D vertical FG type NAND cell with separated-sidewall control gate (S-SCG) structure for the reliable MLC operation. Above all, we successfully demonstrate the fully suppressed disturbance problems, such as indirect programming of the unselected cells, hot electron injection of the edge cells and direct influence to the neighboring passing cells, by using the S-SCG with 30 nm pillar size.

Force sensing using 3D displacement measurements in linear elastic bodies

NASA Astrophysics Data System (ADS)

Feng, Xinzeng; Hui, Chung-Yuen

2016-07-01

In cell traction microscopy, the mechanical forces exerted by a cell on its environment is usually determined from experimentally measured displacement by solving an inverse problem in elasticity. In this paper, an innovative numerical method is proposed which finds the "optimal" traction to the inverse problem. When sufficient regularization is applied, we demonstrate that the proposed method significantly improves the widely used approach using Green's functions. Motivated by real cell experiments, the equilibrium condition of a slowly migrating cell is imposed as a set of equality constraints on the unknown traction. Our validation benchmarks demonstrate that the numeric solution to the constrained inverse problem well recovers the actual traction when the optimal regularization parameter is used. The proposed method can thus be applied to study general force sensing problems, which utilize displacement measurements to sense inaccessible forces in linear elastic bodies with a priori constraints.

Development and Evaluation of the Tigriopus Course-Based Undergraduate Research Experience: Impacts on Students' Content Knowledge, Attitudes, and Motivation in a Majors Introductory Biology Course.

PubMed

Olimpo, Jeffrey T; Fisher, Ginger R; DeChenne-Peters, Sue Ellen

2016-01-01

Within the past decade, course-based undergraduate research experiences (CUREs) have emerged as a viable mechanism to enhance novices' development of scientific reasoning and process skills in the science, technology, engineering, and mathematics disciplines. Recent evidence within the bioeducation literature suggests that student engagement in such experiences not only increases their appreciation for and interest in scientific research but also enhances their ability to "think like a scientist." Despite these critical outcomes, few studies have objectively explored CURE versus non-CURE students' development of content knowledge, attitudes, and motivation in the discipline, particularly among nonvolunteer samples. To address these concerns, we adopted a mixed-methods approach to evaluate the aforementioned outcomes following implementation of a novel CURE in an introductory cell/molecular biology course. Results indicate that CURE participants exhibited more expert-like outcomes on these constructs relative to their non-CURE counterparts, including in those areas related to self-efficacy, self-determination, and problem-solving strategies. Furthermore, analysis of end-of-term survey data suggests that select features of the CURE, such as increased student autonomy and collaboration, mediate student learning and enjoyment. Collectively, this research provides novel insights into the benefits achieved as a result of CURE participation and can be used to guide future development and evaluation of authentic research opportunities. © 2016 J. T. Olimpo et al. CBE—Life Sciences Education © 2016 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Fuel cells for transport: can the promise be fulfilled? Technical requirements and demands from customers

NASA Astrophysics Data System (ADS)

Klaiber, Thomas

The paper discusses the technical requirements and the customer demands for vehicles that have an on-board methanol reformer and fuel cells. The research concentrates on the technical developmental risks which include minimizing volume, reducing weight and, at the same time, improving efficiency and system dynamics. Fuel cell powered vehicles with methanol reformers are not only suitable for a niche market but also these vehicles will compete with conventional vehicles. The greatest hindrance will be the price of the fuel cell. A possible progressive development of the number of fuel cell powered vehicles in conjunction with a reduction in costs will be discussed in the paper. When fuel cell vehicles come to the market it is necessary that an infrastructure for the fuel methanol or hydrogen is installed. Therefore, it will only be possible to introduce fuel cell vehicles into special markets, e.g. California. Such a process will need to be subsidized by additional incentives like tax concessions. Today there are many technical risks and unsolved problems relating to production technologies, infrastructure, and costs. Nevertheless, among the alternative power units, the fuel cell seems to be the only one that might be competitive to the conventional power unit, especially relating to emissions.

TTWand NHT in problem solving

NASA Astrophysics Data System (ADS)

Anthycamurty, R. C. C.; Mardiyana; Saputro, D. R. S.

2018-05-01

This research aims to analyze and determine effect of the model on problem solving. Subjects in this research are students of class X SMK in Purworejo. The learning model used in this research was TTW in class experimental 1 and NHT class experiment 2. This research used quasi experiment. Data analysis technique in this research used ANOVA two way. Data collection techniques in this research used tests to measure student problem solving and GEFT to measure students' cognitive style. The results of this research indicate that there are differences in problem solving between experimental classes used TTW and NHT. The impact of this research is that students are able to remind problem solving used learning model and to know cognitive style of the students.

How to Arrive at Good Research Questions?

ERIC Educational Resources Information Center

Gafoor, K. Abdul

2008-01-01

Identifying an area of research a topic, deciding on a problem, and formulating it in to a researchable question are very difficult stages in the whole research process at least for beginners. Few books on research methodology elaborates the various process involved in problem selection and clarification. Viewing research and problem selection as…

NASA Solar Array Demonstrates Commercial Potential

NASA Technical Reports Server (NTRS)

Creech, Gray

2006-01-01

A state-of-the-art solar-panel array demonstration site at NASA's Dryden Flight Research Center provides a unique opportunity for studying the latest in high-efficiency solar photovoltaic cells. This five-kilowatt solar-array site (see Figure 1) is a technology-transfer and commercialization success for NASA. Among the solar cells at this site are cells of a type that was developed in Dryden Flight Research Center s Environmental Research Aircraft and Sensor Technology (ERAST) program for use in NASA s Helios solar-powered airplane. This cell type, now denoted as A-300, has since been transferred to SunPower Corporation of Sunnyvale, California, enabling mass production of the cells for the commercial market. High efficiency separates these advanced cells from typical previously commercially available solar cells: Whereas typical previously commercially available cells are 12 to 15 percent efficient at converting sunlight to electricity, these advanced cells exhibit efficiencies approaching 23 percent. The increase in efficiency is due largely to the routing of electrical connections behind the cells (see Figure 2). This approach to increasing efficiency originated as a solution to the problem of maximizing the degree of utilization of the limited space available atop the wing of the Helios airplane. In retrospect, the solar cells in use at this site could be used on Helios, but the best cells otherwise commercially available could not be so used, because of their lower efficiencies. Historically, solar cells have been fabricated by use of methods that are common in the semiconductor industry. One of these methods includes the use of photolithography to define the rear electrical-contact features - diffusions, contact openings, and fingers. SunPower uses these methods to produce the advanced cells. To reduce fabrication costs, SunPower continues to explore new methods to define the rear electrical-contact features. The equipment at the demonstration site includes two fixed-angle solar arrays and one single-axis Sun-tracking array. One of the fixed arrays contains typical less-efficient commercial solar cells and is being used as a baseline for comparison of the other fixed array, which contains the advanced cells. The Sun-tracking array tilts to follow the Sun, using an advanced, real-time tracking device rather than customary pre-programmed mechanisms. Part of the purpose served by the demonstration is to enable determination of any potential advantage of a tracking array over a fixed array. The arrays are monitored remotely on a computer that displays pertinent information regarding the functioning of the arrays.

Cutaneous Scarring: Basic Science, Current Treatments, and Future Directions.

PubMed

Marshall, Clement D; Hu, Michael S; Leavitt, Tripp; Barnes, Leandra A; Lorenz, H Peter; Longaker, Michael T

2018-02-01

Significance: Scarring of the skin from burns, surgery, and injury constitutes a major burden on the healthcare system. Patients affected by major scars, particularly children, suffer from long-term functional and psychological problems. Recent Advances: Scarring in humans is the end result of the wound healing process, which has evolved to rapidly repair injuries. Wound healing and scar formation are well described on the cellular and molecular levels, but truly effective molecular or cell-based antiscarring treatments still do not exist. Recent discoveries have clarified the role of skin stem cells and fibroblasts in the regeneration of injuries and formation of scar. Critical Issues: It will be important to show that new advances in the stem cell and fibroblast biology of scarring can be translated into therapies that prevent and reduce scarring in humans without major side effects. Future Directions: Novel therapies involving the use of purified human cells as well as agents that target specific cells and modulate the immune response to injury are currently undergoing testing. In the basic science realm, researchers continue to refine our understanding of the role that particular cell types play in the development of scar.

[Investigation of permeability of intranasal formulations using Side-Bi-Side horizontal diffusion cell].

PubMed

Horváth Tamás; Ambrus, Rita; Szabóné, Révész Piroska

2015-01-01

Nowadays the nasal route has received a great attention as a reliable administration for the systemic administration. In the Department of Pharmaceutical Technology, University of Szeged, the main research work is the design and development of innovative nasal formulations, which can open new possibilities for some well-known agents and may also help some drug-candidates delivery problems. The aim of this work was to present some reliable models for investigation of permeability, such as Spectra/Por Dialisys Membran, ZelluTrans/Roth Mini Dialyzer, μFLUX diffusion Cell, Navicyte Vertical and Horizontal Diffusion Chamber System and In-line Cell. In addition, the horizontal membrane diffusion model (Side-Bi-Side) was used to investigate in vitro and ex vivo studies of permeability of meloxicam in comparison with the vertical diffusion cell (Franz). The present study investigated the meloxicam in different dosage forms (powder, spray, gel). It was found that the Side-Bi-Side cell is suitable to test the nasal formulations, but the uniform distribution of the active substance cannot be ensured in donor place by increasing the viscosity of the compositions, therefore the Franz cell is recommended for investigation of nasal gel. Previous measurement cannot be found related to this topic.

Antidiabetic and cytotoxicity screening of five medicinal plants used by traditional African health practitioners in the Nelson Mandela Metropole, South Africa.

PubMed

van Huyssteen, Mea; Milne, Pieter J; Campbell, Eileen E; van de Venter, Maryna

2011-01-01

Diabetes mellitus is a growing problem in South Africa and of concern to traditional African health practitioners in the Nelson Mandela Metropole, because they experience a high incidence of diabetic cases in their practices. A collaborative research project with these practitioners focused on the screening of Bulbine frutescens, Ornithogalum longibracteatum, Ruta graveolens, Tarchonanthus camphoratus and Tulbaghia violacea for antidiabetic and cytotoxic potential. In vitro glucose utilisation assays with Chang liver cells and C2C12 muscle cells, and growth inhibition assays with Chang liver cells were conducted. The aqueous extracts of Bulbine frutescens (143.5%), Ornithogalum longibracteatum (131.9%) and Tarchonanthus camphoratus (131.5%) showed significant increased glucose utilisation activity in Chang liver cells. The ethanol extracts of Ruta graveolens (136.9%) and Tulbaghia violacea (140.5%) produced the highest increase in glucose utilisation in C2C12 muscle cells. The ethanol extract of Bulbine frutescens produced the most pronounced growth inhibition (33.3%) on Chang liver cells. These findings highlight the potential for the use of traditional remedies in the future for the management of diabetes and it is recommended that combinations of these plants be tested in future.

Hyaluronic Acid (HA) Scaffolds and Multipotent Stromal Cells (MSCs) in Regenerative Medicine.

PubMed

Prè, Elena Dai; Conti, Giamaica; Sbarbati, Andrea

2016-12-01

Traditional methods for tissue regeneration commonly used synthetic scaffolds to regenerate human tissues. However, they had several limitations, such as foreign body reactions and short time duration. In order to overcome these problems, scaffolds made of natural polymers are preferred. One of the most suitable and widely used materials to fabricate these scaffolds is hyaluronic acid. Hyaluronic acid is the primary component of the extracellular matrix of the human connective tissue. It is an ideal material for scaffolds used in tissue regeneration, thanks to its properties of biocompatibility, ease of chemical functionalization and degradability. In the last few years, especially from 2010, scientists have seen that the cell-based engineering of these natural scaffolds allows obtaining even better results in terms of tissue regeneration and the research started to grow in this direction. Multipotent stromal cells, also known as mesenchymal stem cells, plastic-adherent cells isolated from bone marrow and other mesenchymal tissues, with self-renew and multi-potency properties are ideal candidates for this aim. Normally, they are pre-seeded onto these scaffolds before their implantation in vivo. This review discusses the use of hyaluronic acid-based scaffolds together with multipotent stromal cells, as a very promising tool in regenerative medicine.

Implementation Plans for a Systems Microbiology and Extremophile Research Facility

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

Wiley, H. S.

Introduction Biological organisms long ago solved many problems for which scientists and engineers seek solutions. Microbes in particular offer an astonishingly diverse set of capabilities that can help revolutionize our approach to solving many important DOE problems. For example, photosynthetic organisms can generate hydrogen from light while simultaneously sequestering carbon. Others can produce enzymes that break down cellulose and other biomass to produce liquid fuels. Microbes in water and soil can capture carbon and store it in the earth and ocean depths. Understanding the dynamic interaction between living organisms and the environment is critical to predicting and mitigating the impactsmore » of energy-production-related activities on the environment and human health. Collectively, microorganisms contain most of the biochemical diversity on Earth and they comprise nearly one-half of its biomass. They primary impact the planet by acting as catalysts of biogeochemical cycles; they capture light energy and fix CO2 in the worlds oceans, they degrade plant polymers and convert them to humus in soils, they weather rocks and facilitate mineral precipitation. Although the ability of selected microorganisms to participate in these processes is known, they rarely live in monoculture but rather function within communities. In spite of this, little is known about the composition of microbial communities and how individual species function within them. We lack an understanding of the nature of the individual organisms and their genes, how they interact to perform complex functions such as energy and materials exchange, how they sense and respond to their environment and how they evolve and adapt to environmental change. Understanding these aspects of microbes and their communities would be transformational with far-reaching impacts on climate, energy and human health. This knowledge would create a foundation for predicting their behavior and, ultimately, manipulating them to solve DOE problems. Recent advances in whole-genome sequencing for a variety of organisms and improvements in high-throughput instrumentation have contributed to a rapid transition of the biological research paradigm towards understanding biology at a systems level. As a result, biology is evolving from a descriptive to a quantitative, ultimately predictive science where the ability to collect and productively use large amounts of biological data is crucial. Understanding how the ensemble of proteins in cells gives rise to biological outcomes is fundamental to systems biology. These advances will require new technologies and approaches to measure and track the temporal and spatial disposition of proteins in cells and how networks of proteins and other regulatory molecules give rise to specific activities. The DOE has a strong interest in promoting the application of systems biology to understanding microbial function and this comprises a major focus of its Genomics:GTL program. A major problem in pursuing what has been termed “systems microbiology” is the lack of the facilities and infrastructure for conducting this new style of research. To solve this problem, the Genomics:GTL program has funded a number of large-scale research centers focused on either mission-oriented outcomes, such as bioenergy, or basic technologies, such as gene sequencing, high-throughput proteomics or the identification of protein complexes. Although these centers generate data that will be useful to the research community, their scientific goals are relatively narrow and are not designed to accommodate the general community need for advanced capabilities for systems microbiology research.« less

Examining problem solving in physics-intensive Ph.D. research

NASA Astrophysics Data System (ADS)

Leak, Anne E.; Rothwell, Susan L.; Olivera, Javier; Zwickl, Benjamin; Vosburg, Jarrett; Martin, Kelly Norris

2017-12-01

Problem-solving strategies learned by physics undergraduates should prepare them for real-world contexts as they transition from students to professionals. Yet, graduate students in physics-intensive research face problems that go beyond problem sets they experienced as undergraduates and are solved by different strategies than are typically learned in undergraduate coursework. This paper expands the notion of problem solving by characterizing the breadth of problems and problem-solving processes carried out by graduate students in physics-intensive research. We conducted semi-structured interviews with ten graduate students to determine the routine, difficult, and important problems they engage in and problem-solving strategies they found useful in their research. A qualitative typological analysis resulted in the creation of a three-dimensional framework: context, activity, and feature (that made the problem challenging). Problem contexts extended beyond theory and mathematics to include interactions with lab equipment, data, software, and people. Important and difficult contexts blended social and technical skills. Routine problem activities were typically well defined (e.g., troubleshooting), while difficult and important ones were more open ended and had multiple solution paths (e.g., evaluating options). In addition to broadening our understanding of problems faced by graduate students, our findings explore problem-solving strategies (e.g., breaking down problems, evaluating options, using test cases or approximations) and characteristics of successful problem solvers (e.g., initiative, persistence, and motivation). Our research provides evidence of the influence that problems students are exposed to have on the strategies they use and learn. Using this evidence, we have developed a preliminary framework for exploring problems from the solver's perspective. This framework will be examined and refined in future work. Understanding problems graduate students face and the strategies they use has implications for improving how we approach problem solving in undergraduate physics and physics education research.

BioPreDyn-bench: a suite of benchmark problems for dynamic modelling in systems biology.

PubMed

Villaverde, Alejandro F; Henriques, David; Smallbone, Kieran; Bongard, Sophia; Schmid, Joachim; Cicin-Sain, Damjan; Crombach, Anton; Saez-Rodriguez, Julio; Mauch, Klaus; Balsa-Canto, Eva; Mendes, Pedro; Jaeger, Johannes; Banga, Julio R

2015-02-20

Dynamic modelling is one of the cornerstones of systems biology. Many research efforts are currently being invested in the development and exploitation of large-scale kinetic models. The associated problems of parameter estimation (model calibration) and optimal experimental design are particularly challenging. The community has already developed many methods and software packages which aim to facilitate these tasks. However, there is a lack of suitable benchmark problems which allow a fair and systematic evaluation and comparison of these contributions. Here we present BioPreDyn-bench, a set of challenging parameter estimation problems which aspire to serve as reference test cases in this area. This set comprises six problems including medium and large-scale kinetic models of the bacterium E. coli, baker's yeast S. cerevisiae, the vinegar fly D. melanogaster, Chinese Hamster Ovary cells, and a generic signal transduction network. The level of description includes metabolism, transcription, signal transduction, and development. For each problem we provide (i) a basic description and formulation, (ii) implementations ready-to-run in several formats, (iii) computational results obtained with specific solvers, (iv) a basic analysis and interpretation. This suite of benchmark problems can be readily used to evaluate and compare parameter estimation methods. Further, it can also be used to build test problems for sensitivity and identifiability analysis, model reduction and optimal experimental design methods. The suite, including codes and documentation, can be freely downloaded from the BioPreDyn-bench website, https://sites.google.com/site/biopredynbenchmarks/ .

How Can We Improve Problem Solving in Undergraduate Biology? Applying Lessons from 30 Years of Physics Education Research

PubMed Central

Hoskinson, A.-M.; Caballero, M. D.; Knight, J. K.

2013-01-01

If students are to successfully grapple with authentic, complex biological problems as scientists and citizens, they need practice solving such problems during their undergraduate years. Physics education researchers have investigated student problem solving for the past three decades. Although physics and biology problems differ in structure and content, the instructional purposes align closely: explaining patterns and processes in the natural world and making predictions about physical and biological systems. In this paper, we discuss how research-supported approaches developed by physics education researchers can be adopted by biologists to enhance student problem-solving skills. First, we compare the problems that biology students are typically asked to solve with authentic, complex problems. We then describe the development of research-validated physics curricula emphasizing process skills in problem solving. We show that solving authentic, complex biology problems requires many of the same skills that practicing physicists and biologists use in representing problems, seeking relationships, making predictions, and verifying or checking solutions. We assert that acquiring these skills can help biology students become competent problem solvers. Finally, we propose how biology scholars can apply lessons from physics education in their classrooms and inspire new studies in biology education research. PMID:23737623

New challenges in microalgae biotechnology.

PubMed

Valverde, Federico; Romero-Campero, Francisco J; León, Rosa; Guerrero, Miguel G; Serrano, Aurelio

2016-08-01

Photosynthetic protists, also called microalgae, have been systematically studied for more than a century. However, only recently broad biotechnological applications have fostered a novel wave of research on their potentialities as sustainable resources of renewable energy as well as valuable industrial and agro-food products. At the recent VII European Congress of Protistology held in Seville, three outstanding examples of different research strategies on microalgae with biotechnological implications were presented, which suggested that integrative approaches will produce very significant advances in this field in the next future. In any case, intense research and the application of systems biology and genetic engineering techniques are absolutely essential to reach the full potential of microalgae as cell-factories of bio-based products and, therefore, could contribute significantly to solve the problems of biosustainability and energy shortage. Copyright © 2016 Elsevier GmbH. All rights reserved.

Heart Failure With Preserved Ejection Fraction in Diabetes: Mechanisms and Management.

PubMed

Meagher, Patrick; Adam, Mohamed; Civitarese, Robert; Bugyei-Twum, Antoinette; Connelly, Kim A

2018-05-01

Diabetes mellitus (DM) is a major cause of heart failure in the Western world, either secondary to coronary artery disease or from a distinct entity known as "diabetic cardiomyopathy." Furthermore, heart failure with preserved ejection fraction (HFpEF) is emerging as a significant clinical problem for patients with DM. Current clinical data suggest that between 30% and 40% of patients with HFpEF suffer from DM. The typical structural phenotype of the HFpEF heart consists of endothelial dysfunction, increased interstitial and perivascular fibrosis, cardiomyocyte stiffness, and hypertrophy along with advanced glycation end products deposition. There is a myriad of mechanisms that result in the phenotypical HFpEF heart including impaired cardiac metabolism and substrate utilization, altered insulin signalling leading to protein kinase C activation, advanced glycated end products deposition, prosclerotic cytokine activation (eg, transforming growth factor-β activation), along with impaired nitric oxide production from the endothelium. Moreover, recent investigations have focused on the role of endothelial-myocyte interactions. Despite intense research, current therapeutic strategies have had little effect on improving morbidity and mortality in patients with DM and HFpEF. Possible explanations for this include a limited understanding of the role that direct cell-cell communication or indirect cell-cell paracrine signalling plays in the pathogenesis of DM and HFpEF. Additionally, integrins remain another important mediator of signals from the extracellular matrix to cells within the failing heart and might play a significant role in cell-cell cross-talk. In this review we discuss the characteristics and mechanisms of DM and HFpEF to stimulate potential future research for patients with this common, and morbid condition. Copyright © 2018 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

VirtualLeaf: an open-source framework for cell-based modeling of plant tissue growth and development.

PubMed

Merks, Roeland M H; Guravage, Michael; Inzé, Dirk; Beemster, Gerrit T S

2011-02-01

Plant organs, including leaves and roots, develop by means of a multilevel cross talk between gene regulation, patterned cell division and cell expansion, and tissue mechanics. The multilevel regulatory mechanisms complicate classic molecular genetics or functional genomics approaches to biological development, because these methodologies implicitly assume a direct relation between genes and traits at the level of the whole plant or organ. Instead, understanding gene function requires insight into the roles of gene products in regulatory networks, the conditions of gene expression, etc. This interplay is impossible to understand intuitively. Mathematical and computer modeling allows researchers to design new hypotheses and produce experimentally testable insights. However, the required mathematics and programming experience makes modeling poorly accessible to experimental biologists. Problem-solving environments provide biologically intuitive in silico objects ("cells", "regulation networks") required for setting up a simulation and present those to the user in terms of familiar, biological terminology. Here, we introduce the cell-based computer modeling framework VirtualLeaf for plant tissue morphogenesis. The current version defines a set of biologically intuitive C++ objects, including cells, cell walls, and diffusing and reacting chemicals, that provide useful abstractions for building biological simulations of developmental processes. We present a step-by-step introduction to building models with VirtualLeaf, providing basic example models of leaf venation and meristem development. VirtualLeaf-based models provide a means for plant researchers to analyze the function of developmental genes in the context of the biophysics of growth and patterning. VirtualLeaf is an ongoing open-source software project (http://virtualleaf.googlecode.com) that runs on Windows, Mac, and Linux.

Flexibility in Mathematics Problem Solving Based on Adversity Quotient

NASA Astrophysics Data System (ADS)

Dina, N. A.; Amin, S. M.; Masriyah

2018-01-01

Flexibility is an ability which is needed in problem solving. One of the ways in problem solving is influenced by Adversity Quotient (AQ). AQ is the power of facing difficulties. There are three categories of AQ namely climber, camper, and quitter. This research is a descriptive research using qualitative approach. The aim of this research is to describe flexibility in mathematics problem solving based on Adversity Quotient. The subjects of this research are climber student, camper student, and quitter student. This research was started by giving Adversity Response Profile (ARP) questioner continued by giving problem solving task and interviews. The validity of data measurement was using time triangulation. The results of this research shows that climber student uses two strategies in solving problem and doesn’t have difficulty. The camper student uses two strategies in solving problem but has difficulty to finish the second strategies. The quitter student uses one strategy in solving problem and has difficulty to finish it.

Improvement of mouse cloning using nuclear transfer-derived embryonic stem cells and/or histone deacetylase inhibitor.

PubMed

Wakayama, Sayaka; Wakayama, Teruhiko

2010-01-01

Nuclear transfer-derived ES (ntES) cell lines can be established from somatic cell nuclei with a relatively high success rate. Although ntES cells have been shown to be equivalent to ES cells, there are ethical objections concerning human cells, such as the use of fresh oocyte donation from young healthy woman. In contrast, the use of induced pluripotent stem (iPS) cells for cloning poses few ethical problems and is a relatively easy technique compared with nuclear transfer. Therefore, although there are several reports proposing the use of ntES cells as a model of regenerative medicine, the use of these cells in preliminary medical research is waning. However, in theory, 5 to 10 donor cells can establish one ntES cell line and, once established, these cells will propagate indefinitely. These cells can be used to generate cloned animals from ntES cell lines using a second round of NT. Even in infertile and "unclonable" strains of mice, we can generate offspring from somatic cells by combining cloning with ntES technology. Moreover, cloned offspring can be generated potentially even from the nuclei of dead bodies or freeze-dried cells via ntES cells, such as from an extinct frozen animal. Currently, only the ntES technology is available for this purpose, because all other techniques, including iPS cell derivation, require significant numbers of living donor cells. This review describes how to improve the efficiency of cloning, the establishment of clone-derived embryonic stem cells and further applications.

Effect of Concentrated Growth Factor (CGF) on the Promotion of Osteogenesis in Bone Marrow Stromal Cells (BMSC) in vivo.

PubMed

Chen, Xia; Wang, Jian; Yu, Li; Zhou, Jia; Zheng, Danning; Zhang, Bo

2018-04-12

The therapeutic method traditionally used in bone defect reconstruction is autologous bone grafting. The most common problems affecting this type of repair approach are bone absorption and donor trauma. The approach taken in this study overcomes these problems. Bone marrow stromal cells (BMSCs) provided the crucial seed cells. Fibrin biological scaffolds were formed by combining the BMSCs with concentrated growth factor (CGF). BMSCs were isolated from Wistar rat femurs; CGF was prepared from rat heart blood. Five repair groups were created for comparative purposes: (A) CGF + BMSCs; (B) CGF; (C) collagen + BMSCs; (D) collagen; (E) blank. After three months, the rats were sacrificed, and histopathology and three-dimensional CT images produced. Bone regeneration was significantly higher in the (A) CGF + BMSC group; osteogenesis was lower in the (B) CGF and (C) collagen + BMSC groups, at very similar levels; the (D) collagen and (E) blank groups scored the lowest results. Our research suggests that combining CGF with BMSCs leads to the formation of fibrin scaffolds that have a powerful effect on osteogenesis as well as a subsidiary angiogenic effect. SEM images of the CGF scaffolds cultured with BMSCs confirmed good CGF biocompatibility. The superior osteoinductive activity of the CGF + BMSC combination makes it an excellent biomaterial for bone regeneration.

Building better bone: The weaving of biologic and engineering strategies for managing bone loss.

PubMed

Schwartz, Andrew M; Schenker, Mara L; Ahn, Jaimo; Willett, Nick J

2017-09-01

Segmental bone loss remains a challenging clinical problem for orthopaedic trauma surgeons. In addition to the missing bone itself, the local tissues (soft tissue, vascular) are often highly traumatized as well, resulting in a less than ideal environment for bone regeneration. As a result, attempts at limb salvage become a highly expensive endeavor, often requiring multiple operations and necessitating the use of every available strategy (autograft, allograft, bone graft substitution, Masquelet, bone transport, etc.) to achieve bony union. A cost-sensitive, functionally appropriate, and volumetrically adequate engineered substitute would be practice-changing for orthopaedic trauma surgeons and these patients with difficult clinical problems. In tissue engineering and bone regeneration fields, numerous research efforts continue to make progress toward new therapeutic interventions for segmental bone loss, including novel biomaterial development as well as cell-based strategies. Despite an ever-evolving literature base of these new therapeutic and engineered options, there remains a disconnect with the clinical practice, with very few translating into clinical use. A symposium entitled "Building better bone: The weaving of biologic and engineering strategies for managing bone loss," was presented at the 2016 Orthopaedic Research Society Conference to further explore this engineering-clinical disconnect, by surveying basic, translational, and clinical researchers along with orthopaedic surgeons and proposing ideas for pushing the bar forward in the field of segmental bone loss. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1855-1864, 2017. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Ant Colony Optimization Algorithm for Centralized Dynamic Channel Allocation in Multi-Cell OFDMA Systems

NASA Astrophysics Data System (ADS)

Kim, Hyo-Su; Kim, Dong-Hoi

The dynamic channel allocation (DCA) scheme in multi-cell systems causes serious inter-cell interference (ICI) problem to some existing calls when channels for new calls are allocated. Such a problem can be addressed by advanced centralized DCA design that is able to minimize ICI. Thus, in this paper, a centralized DCA is developed for the downlink of multi-cell orthogonal frequency division multiple access (OFDMA) systems with full spectral reuse. However, in practice, as the search space of channel assignment for centralized DCA scheme in multi-cell systems grows exponentially with the increase of the number of required calls, channels, and cells, it becomes an NP-hard problem and is currently too complicated to find an optimum channel allocation. In this paper, we propose an ant colony optimization (ACO) based DCA scheme using a low-complexity ACO algorithm which is a kind of heuristic algorithm in order to solve the aforementioned problem. Simulation results demonstrate significant performance improvements compared to the existing schemes in terms of the grade of service (GoS) performance and the forced termination probability of existing calls without degrading the system performance of the average throughput.

Reduction of the discretization stencil of direct forcing immersed boundary methods on rectangular cells: The ghost node shifting method

NASA Astrophysics Data System (ADS)

Picot, Joris; Glockner, Stéphane

2018-07-01

We present an analytical study of discretization stencils for the Poisson problem and the incompressible Navier-Stokes problem when used with some direct forcing immersed boundary methods. This study uses, but is not limited to, second-order discretization and Ghost-Cell Finite-Difference methods. We show that the stencil size increases with the aspect ratio of rectangular cells, which is undesirable as it breaks assumptions of some linear system solvers. To circumvent this drawback, a modification of the Ghost-Cell Finite-Difference methods is proposed to reduce the size of the discretization stencil to the one observed for square cells, i.e. with an aspect ratio equal to one. Numerical results validate this proposed method in terms of accuracy and convergence, for the Poisson problem and both Dirichlet and Neumann boundary conditions. An improvement on error levels is also observed. In addition, we show that the application of the chosen Ghost-Cell Finite-Difference methods to the Navier-Stokes problem, discretized by a pressure-correction method, requires an additional interpolation step. This extra step is implemented and validated through well known test cases of the Navier-Stokes equations.

The usefulness of three-dimensional cell culture in induction of cancer stem cells from esophageal squamous cell carcinoma cell lines

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

Fujiwara, Daisuke; Kato, Kazunori, E-mail: kzkatou@juntendo.ac.jp; Department of Atopy Research Center, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421

2013-05-17

Highlights: •Spheroids were created from esophageal carcinoma cells using NanoCulture® Plates. •The proportion of strongly ALDH-positive cells increased in 3-D culture. •Expression of cancer stem cell-related genes was enhanced in 3-D culture. •CA-9 expression was enhanced, suggesting hypoxia had been induced in 3-D culture. •Drug resistance was increased. 3-D culture is useful for inducing cancer stem cells. -- Abstract: In recent years, research on resistance to chemotherapy and radiotherapy in cancer treatment has come under the spotlight, and researchers have also begun investigating the relationship between resistance and cancer stem cells. Cancer stem cells are assumed to be present inmore » esophageal cancer, but experimental methods for identification and culture of these cells have not yet been established. To solve this problem, we created spheroids using a NanoCulture® Plate (NCP) for 3-dimensional (3-D) cell culture, which was designed as a means for experimentally reproducing the 3-D structures found in the body. We investigated the potential for induction of cancer stem cells from esophageal cancer cells. Using flow cytometry we analyzed the expression of surface antigen markers CD44, CD133, CD338 (ABCG2), CD318 (CDCP1), and CD326 (EpCAM), which are known cancer stem cell markers. None of these surface antigen markers showed enhanced expression in 3-D cultured cells. We then analyzed aldehyde dehydrogenase (ALDH) enzymatic activity using the ALDEFLUOR reagent, which can identify immature cells such as stem cells and precursor cells. 3-D-cultured cells were strongly positive for ALDH enzyme activity. We also analyzed the expression of the stem cell-related genes Sox-2, Nanog, Oct3/4, and Lin28 using RT-PCR. Expression of Sox-2, Nanog, and Lin28 was enhanced. Analysis of expression of the hypoxic surface antigen marker carbonic anhydrase-9 (CA-9), which is an indicator of cancer stem cell induction and maintenance, revealed that CA-9 expression was enhanced, suggesting that hypoxia had been induced. Comparison of cancer drug resistance using cisplatin and doxorubicin in 3-D-cultured esophageal cancer cells showed that cancer drug resistance had increased. These results indicate that 3-D culture of esophageal squamous cell carcinoma lines is a useful method for inducing cancer stem cells.« less

Constructing space difference schemes which satisfy a cell entropy inequality

NASA Technical Reports Server (NTRS)

Merriam, Marshal L.

1989-01-01

A numerical methodology for solving convection problems is presented, using finite difference schemes which satisfy the second law of thermodynamics on a cell-by-cell basis in addition to the usual conservation laws. It is shown that satisfaction of a cell entropy inequality is sufficient, in some cases, to guarantee nonlinear stability. Some details are given for several one-dimensional problems, including the quasi-one-dimensional Euler equations applied to flow in a nozzle.

Lithium-thionyl chloride battery safety

NASA Technical Reports Server (NTRS)

Carter, B.; Williams, R.; Tsay, F.; Rodriguez, A.; Frank, H.

1982-01-01

Primary lithium cells which use LiAlCl4/SOCl2 electrolyte exhibit high energy density and long life. Currently these cells pose a safety problem since they have been found to vent or explode. This paper summarizes experiments to resolve the safety problem of Li-SOCl2 cells by thermal modeling and identification of possibly hazardous intermediates formed during discharge of these cells. A thermal model and mechanism for the reduction of SOCl2 are presented, as well as a discussion of their application to Li-SOCl2 cell safety.

Single-cell paired-end genome sequencing reveals structural variation per cell cycle

PubMed Central

Voet, Thierry; Kumar, Parveen; Van Loo, Peter; Cooke, Susanna L.; Marshall, John; Lin, Meng-Lay; Zamani Esteki, Masoud; Van der Aa, Niels; Mateiu, Ligia; McBride, David J.; Bignell, Graham R.; McLaren, Stuart; Teague, Jon; Butler, Adam; Raine, Keiran; Stebbings, Lucy A.; Quail, Michael A.; D’Hooghe, Thomas; Moreau, Yves; Futreal, P. Andrew; Stratton, Michael R.; Vermeesch, Joris R.; Campbell, Peter J.

2013-01-01

The nature and pace of genome mutation is largely unknown. Because standard methods sequence DNA from populations of cells, the genetic composition of individual cells is lost, de novo mutations in cells are concealed within the bulk signal and per cell cycle mutation rates and mechanisms remain elusive. Although single-cell genome analyses could resolve these problems, such analyses are error-prone because of whole-genome amplification (WGA) artefacts and are limited in the types of DNA mutation that can be discerned. We developed methods for paired-end sequence analysis of single-cell WGA products that enable (i) detecting multiple classes of DNA mutation, (ii) distinguishing DNA copy number changes from allelic WGA-amplification artefacts by the discovery of matching aberrantly mapping read pairs among the surfeit of paired-end WGA and mapping artefacts and (iii) delineating the break points and architecture of structural variants. By applying the methods, we capture DNA copy number changes acquired over one cell cycle in breast cancer cells and in blastomeres derived from a human zygote after in vitro fertilization. Furthermore, we were able to discover and fine-map a heritable inter-chromosomal rearrangement t(1;16)(p36;p12) by sequencing a single blastomere. The methods will expedite applications in basic genome research and provide a stepping stone to novel approaches for clinical genetic diagnosis. PMID:23630320

Immortalized sheep microglial cells are permissive to a diverse range of ruminant viruses.

PubMed

Stanton, James B; Swanson, Beryl; Orozco, Edith; Muñoz-Gutiérrez, Juan F; Evermann, James F; Ridpath, Julia F

2017-12-01

Ruminants, including sheep and goats (small ruminants), are key agricultural animals in many parts of the world. Infectious diseases, including many viral diseases, are significant problems to efficient production of ruminants. Unfortunately, reagents tailored to viruses of ruminants, and especially small ruminants, are lacking compared to other animals more typically used for biomedical research. The purpose of this study was to determine the permissibility of a stably immortalized, sheep microglial cell line to viruses that are reported to infect ruminants: bovine viral diarrhea virus (BVDV), bovine herpesvirus 1 (BoHV-1), small ruminant lentiviruses (SRLV), and bovine respiratory syncytial virus (BRSV). Sublines A and H of previously isolated, immortalized, and characterized (CD14-positive) ovine microglial cells were used. Bovine turbinate cells and goat synovial membrane cells were used for comparison. Cytopathic changes were used to confirm infection of individual wells, which were then counted and used to calculate the 50% tissue culture infectious dose. Uninoculated cells served as negative controls and confirmed that the cells were not previously infected with these viruses using polymerase chain reaction (PCR). Inoculation of the two microglial cell sublines with laboratory and field isolates of BVDV, BoHV-1, and BRSV resulted in viral infection in a manner similar to bovine turbinate cells. Immortalized microglia cells are also permissive to SRLV, similar to goat synovial membrane cells. These immortalized sheep microglial cells provide a new tool for the study of ruminant viruses in ruminant microglial cell line.

Synthesis of polypyrrole within the cell wall of yeast by redox-cycling of [Fe(CN)6](3-)/[Fe(CN)6](4-).

PubMed

Ramanavicius, Arunas; Andriukonis, Eivydas; Stirke, Arunas; Mikoliunaite, Lina; Balevicius, Zigmas; Ramanaviciene, Almira

2016-02-01

Yeast cells are often used as a model system in various experiments. Moreover, due to their high metabolic activity, yeast cells have a potential to be applied as elements in the design of biofuel cells and biosensors. However a wider application of yeast cells in electrochemical systems is limited due to high electric resistance of their cell wall. In order to reduce this problem we have polymerized conducting polymer polypyrrole (Ppy) directly in the cell wall and/or within periplasmic membrane. In this research the formation of Ppy was induced by [Fe(CN)6](3-)ions, which were generated from K4[Fe(CN)6], which was initially added to polymerization solution. The redox process was catalyzed by oxido-reductases, which are present in the plasma membrane of yeast cells. The formation of Ppy was confirmed by spectrophotometry and atomic force microscopy. It was confirmed that the conducting polymer polypyrrole was formed within periplasmic space and/or within the cell wall of yeast cells, which were incubated in solution containing pyrrole, glucose and [Fe(CN)6](4-). After 24h drying at room temperature we have observed that Ppy-modified yeast cell walls retained their initial spherical form. In contrast to Ppy-modified cells, the walls of unmodified yeast have wrinkled after 24h drying. The viability of yeast cells in the presence of different pyrrole concentrations has been evaluated. Copyright © 2015 Elsevier Inc. All rights reserved.

Hydrodynamic Contributions to Amoeboid Cell Motility

NASA Astrophysics Data System (ADS)

Lewis, Owen; Guy, Robert

2012-11-01

Understanding the methods by which cells move is a fundamental problem in modern biology. Recent evidence has shown that the fluid dynamics of cytoplasm can play a vital role in cellular motility. The slime mold Physarum polycephalum provides an excellent model organism for the study of amoeboid motion. In this research, we use a simply analytic model in conjuction with computational experiments to investigate intracellular fluid flow in a simple model of Physarum. Of particlar interest are stresses generated by cytoplasmic flow which may be used to aid in cellular motility. In our numerical model, the Immersed Boundary Method is used to account for such stresses. We investigate the relationship between contraction waves, flow waves, adhesion, and locomotive forces in an attempt to characterize conditions necessary to generate directed motion.

Observational Research: Formalized Curiosity

ERIC Educational Resources Information Center

Skaggs, Paul

2004-01-01

Design research is a valuable tool to help the designer understand the problem that he/she needs to solve. The purpose of design research is to help state or understand the problems better, which will lead to better solutions. Observational research is a design research method for helping the designer understand and define the problem.…

11th IUBMB Focused Meeting on the Aminoacyl-tRNA Synthetases: Sailing a New Sea of Complex Functions in Human Biology and Disease.

PubMed

Francklyn, Christopher; Roy, Herve; Alexander, Rebecca

2018-05-01

The 11th IUBMB Focused Meeting on Aminoacyl-tRNA Synthetases was held in Clearwater Beach, Florida from 29 October⁻2 November 2017, with the aim of presenting the latest research on these enzymes and promoting interchange among aminoacyl-tRNA synthetase (ARS) researchers. Topics covered in the meeting included many areas of investigation, including ARS evolution, mechanism, editing functions, biology in prokaryotic and eukaryotic cells and their organelles, their roles in human diseases, and their application to problems in emerging areas of synthetic biology. In this report, we provide a summary of the major themes of the meeting, citing contributions from the oral presentations in the meeting.

Research on the honeycomb restrain layer application to the high power microwave dielectric window

NASA Astrophysics Data System (ADS)

Zhang, Qingyuan; Shao, Hao; Huang, Wenhua; Guo, Letian

2018-01-01

Dielectric window breakdown is an important problem of high power microwave radiation. A honeycomb layer can suppress the multipactor in two directions to restrain dielectric window breakdown. This paper studies the effect of the honeycomb restrain layer on improving the dielectric window power capability. It also studies the multipactor suppression mechanism by using the electromagnetic particle-in-cell software, gives the design method, and accomplishes the test experiment. The experimental results indicated that the honeycomb restrain layer can effectively improve the power capability twice.

New insights into the dual role of TGF-beta | Center for Cancer Research

Cancer.gov

The dual role of TGF-beta in cancer continues to challenge investigators in the field. TGF-beta is a well-known factor associated with tumor suppression in normal cells and yet promotes tumor progression in advanced stages of cancer. For years, the mechanisms that underpin this conundrum have not been fully understood. Ying Zhang, Ph.D., senior investigator in the Laboratory of Cellular and Molecular Biology, has been exploring this problem by examining and characterizing several key molecules in the TGF-beta signaling pathway. Read more…

Research on the honeycomb restrain layer application to the high power microwave dielectric window.

PubMed

Zhang, Qingyuan; Shao, Hao; Huang, Wenhua; Guo, Letian

2018-01-01

Dielectric window breakdown is an important problem of high power microwave radiation. A honeycomb layer can suppress the multipactor in two directions to restrain dielectric window breakdown. This paper studies the effect of the honeycomb restrain layer on improving the dielectric window power capability. It also studies the multipactor suppression mechanism by using the electromagnetic particle-in-cell software, gives the design method, and accomplishes the test experiment. The experimental results indicated that the honeycomb restrain layer can effectively improve the power capability twice.

X-ray diffraction on radioactive materials

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

Schiferl, D.; Roof, R.B.

1978-01-01

X-ray diffraction studies on radioactive materials are discussed with the aim of providing a guide to new researchers in the field. Considerable emphasis is placed on the safe handling and loading of not-too-exotic samples. Special considerations such as the problems of film blackening by the gamma rays and changes induced by the self-irradiation of the sample are covered. Some modifications of common diffraction techniques are presented. Finally, diffraction studies on radioactive samples under extreme conditions are discussed, with primary emphasis on high-pressure studies involving diamond-anvil cells.

The molecular and cellular basis of gonadal sex reversal in mice and humans

PubMed Central

Warr, Nick; Greenfield, Andy

2012-01-01

The mammalian gonad is adapted for the production of germ cells and is an endocrine gland that controls sexual maturation and fertility. Gonadal sex reversal, namely, the development of ovaries in an XY individual or testes in an XX, has fascinated biologists for decades. The phenomenon suggests the existence of genetic suppressors of the male and female developmental pathways and molecular genetic studies, particularly in the mouse, have revealed controlled antagonism at the core of mammalian sex determination. Both testis and ovary determination represent design solutions to a number of problems: how to generate cells with the right properties to populate the organ primordium; how to produce distinct organs from an initially bipotential primordium; how to pattern an organ when the expression of key cell fate determinants is initiated only in a discrete region of the primordium and extends to other regions asynchronously; how to coordinate the interaction between distinct cell types in time and space and stabilize the resulting morphology; and how to maintain the differentiated state of the organ throughout the adult period. Some of these, and related problems, are common to organogenesis in general; some are distinctive to gonad development. In this review, we discuss recent studies of the molecular and cellular events underlying testis and ovary development, with an emphasis on the phenomenon of gonadal sex reversal and its causes in mice and humans. Finally, we discuss sex-determining loci and disorders of sex development in humans and the future of research in this important area. WIREs Dev Biol 2012, 1:559–577. doi: 10.1002/wdev.42 PMID:23801533

Preliminary results: Root cause investigation of orbital anomalies and failures in NASA standard 50 ampere-hour nickel-cadmium batteries

NASA Technical Reports Server (NTRS)

Toft, Mark R.

1993-01-01

Two lots of NASA standard 50 A.H. Ni-Cd battery cells, manufactured by Gates Aerospace Batteries and built into batteries by McDonnell Douglas, have experienced significant performance problems. The two lots were used on the Compton Gamma Ray Observatory and the Upper Atmosphere Research Satellite. Both of these satellites are Low Earth Orbital (LEO) satellites containing batteries on a parallel bus charged to NASA standard V/T curves using a NASA standard power regulator. The following preliminary conclusions were reached: (1) several plate and cell parameters have migrated within their spec limits over the years (in some cases, from one extreme to the other); (2) several parametric relationships, not generally monitored and therefore not under specification control, have also migrated over the years; (3) many of these changes appear to have taken place as a natural consequence of changes in GE/GAB materials and processes; (4) several of these factors may be 'conspiring' to aggravate known cell failure mechanisms (factors such as heavier plate, less teflon and/or less-uniform teflon, and less electrolyte) but all are still in spec (where specs exist); (5) the weight of the evidence collected to characterize the anomalies and to characterize the negative electrode itself, strongly suggests that alterations to the structure, composition, uniformity, and efficiency of the negative electrode are at the heart of the battery performance problems currently being experienced; and (6) further investigation at all levels (plate, cell, battery, and system) continues to be warranted.

In Vitro Toxicity Screening Technique for Volatile Substances ...

EPA Pesticide Factsheets

In 2007 the National Research Council envisioned the need for inexpensive, high throughput, cell based toxicity testing methods relevant to human health. High Throughput Screening (HTS) in vitro screening approaches have addressed these problems by using robotics. However the challenge is that many of these chemicals are volatile and not amenable to HTS robotic liquid handling applications. We assembled an in vitro cell culture apparatus capable of screening volatile chemicals for toxicity with potential for miniaturization for high throughput. BEAS-2B lung cells were grown in an enclosed culture apparatus under air-liquid interface (ALI) conditions, and exposed to an array of xenobiotics in 5% CO2. Use of ALI conditions allows direct contact of cells with a gas xenobiotic, as well as release of endogenous gaseous molecules without interference by medium on the apical surface. To identify potential xenobiotic-induced perturbations in cell homeostasis, we monitored for alterations of endogenously-produced gaseous molecules in air directly above the cells, termed “headspace”. Alterations in specific endogenously-produced gaseous molecules (e.g., signaling molecules nitric oxide (NO) and carbon monoxide (CO) in headspace is indicative of xenobiotic-induced perturbations of specific cellular processes. Additionally, endogenously produced volatile organic compounds (VOCs) may be monitored in a nonspecific, discovery manner to determine whether cell processes are

Cell segmentation in histopathological images with deep learning algorithms by utilizing spatial relationships.

PubMed

Hatipoglu, Nuh; Bilgin, Gokhan

2017-10-01

In many computerized methods for cell detection, segmentation, and classification in digital histopathology that have recently emerged, the task of cell segmentation remains a chief problem for image processing in designing computer-aided diagnosis (CAD) systems. In research and diagnostic studies on cancer, pathologists can use CAD systems as second readers to analyze high-resolution histopathological images. Since cell detection and segmentation are critical for cancer grade assessments, cellular and extracellular structures should primarily be extracted from histopathological images. In response, we sought to identify a useful cell segmentation approach with histopathological images that uses not only prominent deep learning algorithms (i.e., convolutional neural networks, stacked autoencoders, and deep belief networks), but also spatial relationships, information of which is critical for achieving better cell segmentation results. To that end, we collected cellular and extracellular samples from histopathological images by windowing in small patches with various sizes. In experiments, the segmentation accuracies of the methods used improved as the window sizes increased due to the addition of local spatial and contextual information. Once we compared the effects of training sample size and influence of window size, results revealed that the deep learning algorithms, especially convolutional neural networks and partly stacked autoencoders, performed better than conventional methods in cell segmentation.

Fluorescence lifetime imaging of lipids during 3T3-L1 cell differentiation

NASA Astrophysics Data System (ADS)

Song, Young Sik; Won, Young Jae; Lee, Sang-Hak; Kim, Dug Young

2014-03-01

Obesity is becoming a big health problem in these days. Since increased body weight is due to increased number and size of the triglyceride-storing adipocytes, many researchers are working on differentiation conditions and processes of adipocytes. Adipocytes also work as regulators of whole-body energy homeostasis by secreting several proteins that regulate processes as diverse as haemostasis, blood pressure, immune function, angiogenesis and energy balance. 3T3-L1 cells are widely used cell line for studying adipogenesis because it can differentiate into an adipocyte-like phenotype under appropriate conditions. In this paper, we propose an effective fluorescence lifetime imaging technique which can easily distinguish lipids in membrane and those in lipid droplets. Nile red dyes are attached to lipids in 3T3-L1 cells. Fluorescence lifetime images were taken for 2 week during differentiation procedure of 3T3-L1 cells into adipocytes. We used 488 nm pulsed laser with 5MHz repetition rate and emission wavelength is 520 nm of Nile Red fluorescent dye. Results clearly show that the lifetime of Nile red in lipid droplets are smaller than those in cell membrane. Our results suggest that fluorescence lifetime imaging can be a very powerful tool to monitor lipid droplet formation in adipocytes from 3T3-L1 cells.

Quantitative Analysis of Intracellular Motility Based on Optical Flow Model

PubMed Central

Li, Heng

2017-01-01

Analysis of cell mobility is a key issue for abnormality identification and classification in cell biology research. However, since cell deformation induced by various biological processes is random and cell protrusion is irregular, it is difficult to measure cell morphology and motility in microscopic images. To address this dilemma, we propose an improved variation optical flow model for quantitative analysis of intracellular motility, which not only extracts intracellular motion fields effectively but also deals with optical flow computation problem at the border by taking advantages of the formulation based on L1 and L2 norm, respectively. In the energy functional of our proposed optical flow model, the data term is in the form of L2 norm; the smoothness of the data changes with regional features through an adaptive parameter, using L1 norm near the edge of the cell and L2 norm away from the edge. We further extract histograms of oriented optical flow (HOOF) after optical flow field of intracellular motion is computed. Then distances of different HOOFs are calculated as the intracellular motion features to grade the intracellular motion. Experimental results show that the features extracted from HOOFs provide new insights into the relationship between the cell motility and the special pathological conditions. PMID:29065574

A cGMP-applicable expansion method for aggregates of human neural stem and progenitor cells derived from pluripotent stem cells or fetal brain tissue.

PubMed

Shelley, Brandon C; Gowing, Geneviève; Svendsen, Clive N

2014-06-15

A cell expansion technique to amass large numbers of cells from a single specimen for research experiments and clinical trials would greatly benefit the stem cell community. Many current expansion methods are laborious and costly, and those involving complete dissociation may cause several stem and progenitor cell types to undergo differentiation or early senescence. To overcome these problems, we have developed an automated mechanical passaging method referred to as "chopping" that is simple and inexpensive. This technique avoids chemical or enzymatic dissociation into single cells and instead allows for the large-scale expansion of suspended, spheroid cultures that maintain constant cell/cell contact. The chopping method has primarily been used for fetal brain-derived neural progenitor cells or neurospheres, and has recently been published for use with neural stem cells derived from embryonic and induced pluripotent stem cells. The procedure involves seeding neurospheres onto a tissue culture Petri dish and subsequently passing a sharp, sterile blade through the cells effectively automating the tedious process of manually mechanically dissociating each sphere. Suspending cells in culture provides a favorable surface area-to-volume ratio; as over 500,000 cells can be grown within a single neurosphere of less than 0.5 mm in diameter. In one T175 flask, over 50 million cells can grow in suspension cultures compared to only 15 million in adherent cultures. Importantly, the chopping procedure has been used under current good manufacturing practice (cGMP), permitting mass quantity production of clinical-grade cell products.

A Study of Moroccan Pupils' Difficulties at Second Baccalaureate Year in Solving Chemistry Problems Relating to the Reactivity of Ethanoate Ions and to Copper-Aluminium Cells

ERIC Educational Resources Information Center

Ouasri, Ali

2017-01-01

This paper investigates the difficulties that Moroccan pupils (18-19) of the second Baccalaureate year encountered in solving chemical equilibrium problems relating to ethanoate ions' reactivity with water and methanoic acid, and to copper-aluminum cells. The pupils were asked to provide answers to questions derived from two problems. The…

Electronic media, violence, and adolescents: an emerging public health problem.

PubMed

David-Ferdon, Corinne; Hertz, Marci Feldman

2007-12-01

Adolescents' access to and use of new media technology (e.g., cell phone, personal data assistant, computer for Internet access) are on the rise, and this explosion of technology brings with it potential benefits and risks. Attention is growing about the risk of adolescents to become victims of aggression perpetrated by peers with new technology. In September 2006, the Centers for Disease Control and Prevention convened a panel of experts in technology and youth aggression to examine this specific risk. This special issue of the Journal of Adolescent Health presents the data and recommendations for future directions discussed at the meeting. The articles in the Journal support the argument that electronic aggression is an emerging public health problem in need of additional prevalence and etiological research to support the development and evaluation of effective prevention programs.

Alcohol studies and science: trapped in the velvet cage of medical research? An editorial.

PubMed

Roman, Paul M

2014-01-01

This article offers the author's assessment of the progress in research on alcohol related to alcohol misuse and alcohol use disorders. The historical background of alcohol-problem research is reviewed in the context of defining problems for study and the pattern by which research is funded. Progress in terms of cumulative research has been affected by the lack of central authority and the National Institutes of Health structure within which almost all funding for alcohol research in the United States has occurred. Problems are traced to the particular history and nature of alcohol-problem research, the continuing prominence of moral elements, and particular features of the treatment of alcohol use disorders. Although the scope of activity and production of publications in alcohol research has expanded greatly during the past 75 years, there is a potential shortfall in the cumulative research that has led to solutions to major problems associated with alcohol.

The Problems with Problem Solving: Reflections on the Rise, Current Status, and Possible Future of a Cognitive Research Paradigm

ERIC Educational Resources Information Center

Ohlsson, Stellan

2012-01-01

The research paradigm invented by Allen Newell and Herbert A. Simon in the late 1950s dominated the study of problem solving for more than three decades. But in the early 1990s, problem solving ceased to drive research on complex cognition. As part of this decline, Newell and Simon's most innovative research practices--especially their method for…

Tracking cells in Life Cell Imaging videos using topological alignments.

PubMed

Mosig, Axel; Jäger, Stefan; Wang, Chaofeng; Nath, Sumit; Ersoy, Ilker; Palaniappan, Kannap-pan; Chen, Su-Shing

2009-07-16

With the increasing availability of live cell imaging technology, tracking cells and other moving objects in live cell videos has become a major challenge for bioimage informatics. An inherent problem for most cell tracking algorithms is over- or under-segmentation of cells - many algorithms tend to recognize one cell as several cells or vice versa. We propose to approach this problem through so-called topological alignments, which we apply to address the problem of linking segmentations of two consecutive frames in the video sequence. Starting from the output of a conventional segmentation procedure, we align pairs of consecutive frames through assigning sets of segments in one frame to sets of segments in the next frame. We achieve this through finding maximum weighted solutions to a generalized "bipartite matching" between two hierarchies of segments, where we derive weights from relative overlap scores of convex hulls of sets of segments. For solving the matching task, we rely on an integer linear program. Practical experiments demonstrate that the matching task can be solved efficiently in practice, and that our method is both effective and useful for tracking cells in data sets derived from a so-called Large Scale Digital Cell Analysis System (LSDCAS). The source code of the implementation is available for download from http://www.picb.ac.cn/patterns/Software/topaln.

A pressure relaxation closure model for one-dimensional, two-material Lagrangian hydrodynamics based on the Riemann problem

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

Kamm, James R; Shashkov, Mikhail J

2009-01-01

Despite decades of development, Lagrangian hydrodynamics of strengthfree materials presents numerous open issues, even in one dimension. We focus on the problem of closing a system of equations for a two-material cell under the assumption of a single velocity model. There are several existing models and approaches, each possessing different levels of fidelity to the underlying physics and each exhibiting unique features in the computed solutions. We consider the case in which the change in heat in the constituent materials in the mixed cell is assumed equal. An instantaneous pressure equilibration model for a mixed cell can be cast asmore » four equations in four unknowns, comprised of the updated values of the specific internal energy and the specific volume for each of the two materials in the mixed cell. The unique contribution of our approach is a physics-inspired, geometry-based model in which the updated values of the sub-cell, relaxing-toward-equilibrium constituent pressures are related to a local Riemann problem through an optimization principle. This approach couples the modeling problem of assigning sub-cell pressures to the physics associated with the local, dynamic evolution. We package our approach in the framework of a standard predictor-corrector time integration scheme. We evaluate our model using idealized, two material problems using either ideal-gas or stiffened-gas equations of state and compare these results to those computed with the method of Tipton and with corresponding pure-material calculations.« less

Features and Characteristics of Problem Based Learning

ERIC Educational Resources Information Center

Ceker, Eser; Ozdamli, Fezile

2016-01-01

Throughout the years, there appears to be an increase in Problem Based Learning applications in education; and Problem Based Learning related research areas. The main aim of this research is to underline the fundamentals (basic elements) of Problem Based Learning, investigate the dimensions of research approached to PBL oriented areas (with a look…

Problems of Conducting Research in Organizations: The Case of Police Departments.

ERIC Educational Resources Information Center

Lefkowitz, Joel

This paper presents a description of police research problems in such fashion that it could be generalized to other types of organizations. A two-dimensional taxonomy of problems in conducting psychological research in police departments is discussed. The first dimension concerns generality-uniqueness of the problem, relative to formal…

Magnetically modified bioсells in constant magnetic field

NASA Astrophysics Data System (ADS)

Abramov, E. G.; Panina, L. K.; Kolikov, V. A.; Bogomolova, E. V.; Snetov, V. N.; Cherepkova, I. A.; Kiselev, A. A.

2017-02-01

Paper addresses the inverse problem in determining the area, where the external constant magnetic field captures the biological cells modified by the magnetic nanoparticles. Zero velocity isolines, in area where the modified cells are captured by the magnetic field were determined by numerical method for two locations of the magnet. The problem was solved taking into account the gravitational field, magnetic induction, density of medium, concentration and size of cells, and size and magnetization of nanoparticles attached to the cell. Increase in the number of the nanoparticles attached to the cell and decrease in the cell' size, enlarges the area, where the modified cells are captured and concentrated by the magnet. Solution is confirmed by the visible pattern formation of the modified cells Saccharomyces cerevisiae.

Hydrogen embrittlement in nickel-hydrogen cells

NASA Technical Reports Server (NTRS)

Gross, Sidney

1989-01-01

It was long known that many strong metals can become weakened and brittle as the result of the accumulation of hydrogen within the metal. When the metal is stretched, it does not show normal ductile properties, but fractures prematurely. This problem can occur as the result of a hydrogen evolution reaction such as corrosion or electroplating, or due to hydrogen in the environment at the metal surface. High strength alloys such as steels are especially susceptible to hydrogen embrittlement. Nickel-hydrogen cells commonly use Inconel 718 alloy for the pressure container, and this also is susceptible to hydrogen embrittlement. Metals differ in their susceptibility to embrittlement. Hydrogen embrittlement in nickel-hydrogen cells is analyzed and the reasons why it may or may not occur are discussed. Although Inconel 718 can display hydrogen embrittlement, experience has not identified any problem with nickel-hydrogen cells. No hydrogen embrittlement problem is expected with the 718 alloy pressure container used in nickel-hydrogen cells.

Traction patterns of tumor cells.

PubMed

Ambrosi, D; Duperray, A; Peschetola, V; Verdier, C

2009-01-01

The traction exerted by a cell on a planar deformable substrate can be indirectly obtained on the basis of the displacement field of the underlying layer. The usual methodology used to address this inverse problem is based on the exploitation of the Green tensor of the linear elasticity problem in a half space (Boussinesq problem), coupled with a minimization algorithm under force penalization. A possible alternative strategy is to exploit an adjoint equation, obtained on the basis of a suitable minimization requirement. The resulting system of coupled elliptic partial differential equations is applied here to determine the force field per unit surface generated by T24 tumor cells on a polyacrylamide substrate. The shear stress obtained by numerical integration provides quantitative insight of the traction field and is a promising tool to investigate the spatial pattern of force per unit surface generated in cell motion, particularly in the case of such cancer cells.

Design challenges for space bioreactors

NASA Technical Reports Server (NTRS)

Seshan, P. K.; Petersen, G. R.

1989-01-01

The design of bioreactors for operation under conditions of microgravity presents problems and challenges. Absence of a significant body force such as gravity can have profound consequences for interfacial phenomena. Marangoni convection can no longer be overlooked. Many speculations on the advantages and benefits of microgravity can be found in the literature. Initial bioreactor research considerations for space applications had little regard for the suitability of the designs for conditions of microgravity. Bioreactors can be classified in terms of their function and type of operation. The complex interaction of parameters leading to optimal design and operation of a bioreactor is illustrated by the JSC mammalian cell culture system. The design of a bioreactor is strongly dependent upon its intended use as a production unit for cell mass and/or biologicals or as a research reactor for the study of cell growth and function. Therefore a variety of bioreactor configurations are presented in rapid summary. Following this, a rationale is presented for not attempting to derive key design parameters such as the oxygen transfer coefficient from ground-based data. A set of themes/objectives for flight experiments to develop the expertise for design of space bioreactors is then proposed for discussion. These experiments, carried out systematically, will provide a database from which engineering tools for space bioreactor design will be derived.

Teacher stress research: problems and progress.

PubMed

Pithers, R T

1995-12-01

There is a reasonably large body of published research evidence available which indicates that teaching is a 'highly' or 'extremely highly' stressful occupation for up to one-third of its professionals. Generalisations such as this one, however, are wrought with problems. These problems, for instance, range from confusion about the definition of stress through to how it is to be measured. They include methodological problems inherent in some of the research used to examine the area of teacher stress and as well include, for example, confusion about the effect of mediating variables in the production of stress and strain. This paper examines some of the more important pervasive research problems in current research on teacher stress and makes some suggestions for research progress.

Lineage mapper: A versatile cell and particle tracker

NASA Astrophysics Data System (ADS)

Chalfoun, Joe; Majurski, Michael; Dima, Alden; Halter, Michael; Bhadriraju, Kiran; Brady, Mary

2016-11-01

The ability to accurately track cells and particles from images is critical to many biomedical problems. To address this, we developed Lineage Mapper, an open-source tracker for time-lapse images of biological cells, colonies, and particles. Lineage Mapper tracks objects independently of the segmentation method, detects mitosis in confluence, separates cell clumps mistakenly segmented as a single cell, provides accuracy and scalability even on terabyte-sized datasets, and creates division and/or fusion lineages. Lineage Mapper has been tested and validated on multiple biological and simulated problems. The software is available in ImageJ and Matlab at isg.nist.gov.

The Profile of Creativity and Proposing Statistical Problem Quality Level Reviewed From Cognitive Style

NASA Astrophysics Data System (ADS)

Awi; Ahmar, A. S.; Rahman, A.; Minggi, I.; Mulbar, U.; Asdar; Ruslan; Upu, H.; Alimuddin; Hamda; Rosidah; Sutamrin; Tiro, M. A.; Rusli

2018-01-01

This research aims to reveal the profile about the level of creativity and the ability to propose statistical problem of students at Mathematics Education 2014 Batch in the State University of Makassar in terms of their cognitive style. This research uses explorative qualitative method by giving meta-cognitive scaffolding at the time of research. The hypothesis of research is that students who have field independent (FI) cognitive style in statistics problem posing from the provided information already able to propose the statistical problem that can be solved and create new data and the problem is already been included as a high quality statistical problem, while students who have dependent cognitive field (FD) commonly are still limited in statistics problem posing that can be finished and do not load new data and the problem is included as medium quality statistical problem.

Mathematical Problem Solving. Issues in Research.

ERIC Educational Resources Information Center

Lester, Frank K., Jr., Ed.; Garofalo, Joe, Ed.

This set of papers was originally developed for a conference on Issues and Directions in Mathematics Problem Solving Research held at Indiana University in May 1981. The purpose is to contribute to the clear formulation of the key issues in mathematical problem-solving research by presenting the ideas of actively involved researchers. An…

The neurobiology of individuality

NASA Astrophysics Data System (ADS)

de Bivort, Benjamin

2015-03-01

Individuals often display conspicuously different patterns of behavior, even when they are very closely related genetically. These differences give rise to our sense of individuality, but what is their molecular and neurobiological basis? Individuals that are nominally genetically identical differ at various molecular and neurobiological levels: cell-to-cell variation in somatic genomes, cell-to-cell variation in expression patterns, individual-to-individual variation in neuronal morphology and physiology, and individual-to-individual variation in patterns of brain activity. It is unknown which of these levels is fundamentally causal of behavioral differences. To investigate this problem, we use the fruit fly Drosophila melanogaster, whose genetic toolkit allows the manipulation of each of these mechanistic levels, and whose rapid lifecycle and small size allows for high-throughput automation of behavioral assays. This latter point is crucial; identifying inter-individual behavioral differences requires high sample sizes both within and across individual animals. Automated behavioral characterization is at the heart of our research strategy. In every behavior examined, individual flies have individual behavioral preferences, and we have begun to identify both neural genes and circuits that control the degree of behavioral variability between individuals.

Effects of Mg{sup 2+}, Co{sup 2+}, and Hg{sup 2+} on the nucleus and nucleolus in root tip cells of allium cepa

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

Liu, D.; Jiang, W.; Wang, W.

Metal toxicity in plants has been known for a long time. Much importance has increasingly been attached to the problems of metal pollution with the development of modern industry and agriculture. If metals in plants are accumulated to a large extent, it might seriously affect them. The cytological effects of cobalt and mercury have been studied in Allium cepa by documentation of c-mitosis. Also, the quantification of chromosome aberration in Vicia faba root-tip cells treated by magnesium sulphate and in Allium cepa by metyl mercury chloride and mercuric chloride has been reported. Cytological research on the poisoning effects of Mg,more » Co and Hg on the nuclei and nucleoli in root-tip cells of plants has hardly been reported. The aim of this study was to determine the effects of different concentrations of magnesium, cobalt and mercury ions on root growth, and on the nuclei and nucleoli of root tip cells of Allium-cepa. 20 refs., 3 figs.« less

Interference thinking in constructing students’ knowledge to solve mathematical problems

NASA Astrophysics Data System (ADS)

Jayanti, W. E.; Usodo, B.; Subanti, S.

2018-04-01

This research aims to describe interference thinking in constructing students’ knowledge to solve mathematical problems. Interference thinking in solving problems occurs when students have two concepts that interfere with each other’s concept. Construction of problem-solving can be traced using Piaget’s assimilation and accommodation framework, helping to know the students’ thinking structures in solving the problems. The method of this research was a qualitative method with case research strategy. The data in this research involving problem-solving result and transcripts of interviews about students’ errors in solving the problem. The results of this research focus only on the student who experience proactive interference, where student in solving a problem using old information to interfere with the ability to recall new information. The student who experience interference thinking in constructing their knowledge occurs when the students’ thinking structures in the assimilation and accommodation process are incomplete. However, after being given reflection to the student, then the students’ thinking process has reached equilibrium condition even though the result obtained remains wrong.

Effectiveness of discovery learning model on mathematical problem solving

NASA Astrophysics Data System (ADS)

Herdiana, Yunita; Wahyudin, Sispiyati, Ririn

2017-08-01

This research is aimed to describe the effectiveness of discovery learning model on mathematical problem solving. This research investigate the students' problem solving competency before and after learned by using discovery learning model. The population used in this research was student in grade VII in one of junior high school in West Bandung Regency. From nine classes, class VII B were randomly selected as the sample of experiment class, and class VII C as control class, which consist of 35 students every class. The method in this research was quasi experiment. The instrument in this research is pre-test, worksheet and post-test about problem solving of mathematics. Based on the research, it can be conclude that the qualification of problem solving competency of students who gets discovery learning model on level 80%, including in medium category and it show that discovery learning model effective to improve mathematical problem solving.

Cadmium exposure in newborn rats ovary induces developmental disorders of primordial follicles and the differential expression of SCF/c-kit gene.

PubMed

Zhang, Wenchang; Wu, Tingting; Zhang, Chenyun; Luo, Lingfeng; Xie, Meimei; Huang, Huiling

2017-10-05

Since the 1990s, the rising problem that gonad reproductive toxicity on adult female after exposing to cadmium (Cd), an environmental endocrine disruptor, has attracted high attention at home and abroad,and was systematically studied. Our research focuses on a further problem is that early cadmium exposure (during birth to before puberty) impact on development and function of ovarian cells and its possible mechanism. Our research focuses on the changes of ovarian cells growth and development after the newborn rat ovaries with cadmium exposure in vitro, and different expression of ovarian cells development-related factors, SCF/c-kit and changes of their DNA methylation status. We obtained ovaries from 4-day-old SD rats and cultured them in DMEM/F12 mixed with α-MEM media in vitro. Different doses of cadmium were designed as control, 0.5, 5, 10 and 50μM, and then the constituent ratio of ovarian follicle and follicular oocytes diameter were observed with microscope after 4-h exposure. We found that the increased constituent ratio of original follicle and decreased diameter of all levels of follicular oocytes(compared with control, with statistically significant differences, P<0.01).After the measurement of expression of SCF/c-kit by qRT-PCR and Western Blotting, the mRNA and protein expression of SCF/c-kit in ovarian were both decreased. We further found that the increased constituent ratio of growth follicle and increased diameter of oocytes under the treatment of adding SCF in cell culture media. Finally, MALDI-TOF-MS method showed DNA-low methylation status of SCF/c-kit promoter region after Cd exposure. Overall, we concluded that the exposure of cadimium (5-50μM) on newborn rats ovaries could inhibit follicle development.SCF/c-kit system might mediate follicle development damage caused by cadmium, which is associated with DNA hypomethylation of SCF/c-kit promoter region may be worthy of further study. Copyright © 2017. Published by Elsevier B.V.

Cold start dynamics and temperature sliding observer design of an automotive SOFC APU

NASA Astrophysics Data System (ADS)

Lin, Po-Hsu; Hong, Che-Wun

This paper presents a dynamic model for studying the cold start dynamics and observer design of an auxiliary power unit (APU) for automotive applications. The APU is embedded with a solid oxide fuel cell (SOFC) stack which is a quiet and pollutant-free electric generator; however, it suffers from slow start problem from ambient conditions. The SOFC APU system equips with an after-burner to accelerate the start-up transient in this research. The combustion chamber burns the residual fuel (and air) left from the SOFC to raise the exhaust temperature to preheat the SOFC stack through an energy recovery unit. Since thermal effect is the dominant factor that influences the SOFC transient and steady performance, a nonlinear real-time sliding observer for stack temperature was implemented into the system dynamics to monitor the temperature variation for future controller design. The simulation results show that a 100 W APU system in this research takes about 2 min (in theory) for start-up without considering the thermal limitation of the cell fracture.

Ubiquitous Indoor Geolocation: a Case Study of Jewellery Management System

NASA Astrophysics Data System (ADS)

Nikparvar, B.; Sadeghi-Niaraki, A.; Azari, P.

2014-10-01

Addressing and geolocation for indoor environments are important fields of research in the recent years. The problem of finding location of objects in indoor spaces is proposed to solve in two ways. The first, is to assign coordinates to objects and second is to divide space into cells and detect the presence or absence of objects in each cell to track them. In this paper the second approach is discussed by using Radio Frequency Identification technology to identify and track high value objects in jewellery retail industry. In Ubiquitous Sensor Networks, the reactivity or proactivity of the environment are important issues. Reactive environments wait for a request to response to it. Instead, in proactive spaces, the environment acts in advance to deal with an expected action. In this research, a geo-sensor network containing RFID readers, tags, and antennas which continuously exchange radio frequency signal streams is proposed to manage and monitor jewellery galleries ubiquitously. The system is also equipped with a GIS representation which provides a more user-friendly system to manage a jewellery gallery.

Development and application of biological technologies in fish genetic breeding.

PubMed

Xu, Kang; Duan, Wei; Xiao, Jun; Tao, Min; Zhang, Chun; Liu, Yun; Liu, ShaoJun

2015-02-01

Fish genetic breeding is a process that remolds heritable traits to obtain neotype and improved varieties. For the purpose of genetic improvement, researchers can select for desirable genetic traits, integrate a suite of traits from different donors, or alter the innate genetic traits of a species. These improved varieties have, in many cases, facilitated the development of the aquaculture industry by lowering costs and increasing both quality and yield. In this review, we present the pertinent literatures and summarize the biological bases and application of selection breeding technologies (containing traditional selective breeding, molecular marker-assisted breeding, genome-wide selective breeding and breeding by controlling single-sex groups), integration breeding technologies (containing cross breeding, nuclear transplantation, germline stem cells and germ cells transplantation, artificial gynogenesis, artificial androgenesis and polyploid breeding) and modification breeding technologies (represented by transgenic breeding) in fish genetic breeding. Additionally, we discuss the progress our laboratory has made in the field of chromosomal ploidy breeding of fish, including distant hybridization, gynogenesis, and androgenesis. Finally, we systematically summarize the research status and known problems associated with each technology.

Sleep Disruption in Hematopoietic Cell Transplant Recipients: Prevalence, Severity, and Clinical Management

PubMed Central

Jim, Heather S.L.; Evans, Bryan; Jeong, Jiyeon M.; Gonzalez, Brian D.; Johnston, Laura; Nelson, Ashley M.; Kesler, Shelli; Phillips, Kristin M.; Barata, Anna; Pidala, Joseph; Palesh, Oxana

2014-01-01

Sleep disruption is common among hematopoietic cell transplant (HCT) recipients, with over 50% of patients experiencing sleep disruption pre-transplant, up to 82% experiencing moderate to severe sleep disruption during hospitalization for transplant, and up to 43% in the post-transplant period. These rates of sleep disruption are substantially higher than the general population. Although sleep disruption can be distressing to patients and contribute to diminished quality of life, it is rarely discussed during clinical visits. The goal of the current review is to draw attention to sleep disruption as a clinical problem in HCT in order to facilitate patient education, intervention, and research. The review opens with a discussion of sleep disruption measurement and clinical diagnosis of sleep disorders. An overview of the prevalence, severity, and chronicity of sleep disruption and disorders in patients receiving HCT follows. Current evidence regarding sociodemographic and clinical predictors of sleep disruption and disorders is summarized. The review concludes with suggestions for behavioral and pharmacologic management of sleep disruption and disorders as well as directions for future research. PMID:24747335

Biological effects of weightlessness and clinostatic conditions registered in cells of root meristem and cap of higher plants

NASA Astrophysics Data System (ADS)

Sytnik, K. M.; Kordyum, E. L.; Belyavskaya, N. A.; Nedukha, E. M.; Tarasenko, V. A.

Research in cellular reproduction, differentiation and vital activity, i.e. processes underlying the development and functioning of organisms, plants included, is essential for solving fundamental and applied problems of space biology. Detailed anatomical analysis of roots of higher plants grown on board the Salyut 6 orbital research station show that under conditions of weightlessness for defined duration mitosis, cytokinesis and tissue differentiation in plant vegetative organs occur essentially normally. At the same time, certain rearrangements in the structural organization of cellular organelles - mainly the plastid apparatus, mitochondria, Golgi apparatus and nucleus - are established in the root meristem and cap of the experimental plants. This is evidence for considerable changes in cellular metabolism. The structural changes in the subcellular level arising under spaceflight conditions are partially absent in clinostat experiments designed to simulate weightlessness. Various clinostatic conditions have different influences on the cell structural and functional organization than does space flight. It is suggested that alterations of cellular metabolism under weightlessness and clinostatic conditions occur within existing genetic programs.

Japan's Sunshine Project

NASA Astrophysics Data System (ADS)

1992-07-01

A summary report is given on the results of hydrogen energy research and development achieved during 1991 under the Sunshine Project. In hydrogen manufacturing, regenerative cells that can also generate power as fuel cells were discussed by using solid macromolecular electrolytic films for the case where no electrolysis is carried out with water electrolysis. Yttria stabilized zirconia (YSZ), an oxide solid electrolyte was used for the basic research on high-temperature steam electrolysis. Compositions of hydrogen storage alloys and their deterioration mechanisms were investigated to develop hydrogen transportation and storage technologies. High-density hydrides were searched, and fluidization due to paraffin was discussed. Electrode materials and forming technologies were discussed to develop a hydrogen to power conversion system using hydrogen storage alloys as reversible electrodes. Hydrogen-oxygen combustion was studied in terms of reactive theories, and so was the control of ignition and combustion using ultraviolet ray ignition plasma. Studies were made on hydrogen brittlement in welds on materials in hydrogen utilization and its preventive measures. Surveys were given on technical movements and development problems in high-efficiency, pollution-free hydrogen combustion turbines.

Increased reprogramming of human fetal hepatocytes compared with adult hepatocytes in feeder-free conditions.

PubMed

Hansel, Marc C; Gramignoli, Roberto; Blake, William; Davila, Julio; Skvorak, Kristen; Dorko, Kenneth; Tahan, Veysel; Lee, Brian R; Tafaleng, Edgar; Guzman-Lepe, Jorge; Soto-Gutierrez, Alejandro; Fox, Ira J; Strom, Stephen C

2014-01-01

Hepatocyte transplantation has been used to treat liver disease. The availability of cells for these procedures is quite limited. Human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) may be a useful source of hepatocytes for basic research and transplantation if efficient and effective differentiation protocols were developed and problems with tumorigenicity could be overcome. Recent evidence suggests that the cell of origin may affect hiPSC differentiation. Thus, hiPSCs generated from hepatocytes may differentiate back to hepatocytes more efficiently than hiPSCs from other cell types. We examined the efficiency of reprogramming adult and fetal human hepatocytes. The present studies report the generation of 40 hiPSC lines from primary human hepatocytes under feeder-free conditions. Of these, 37 hiPSC lines were generated from fetal hepatocytes, 2 hiPSC lines from normal hepatocytes, and 1 hiPSC line from hepatocytes of a patient with Crigler-Najjar syndrome, type 1. All lines were confirmed reprogrammed and expressed markers of pluripotency by gene expression, flow cytometry, immunocytochemistry, and teratoma formation. Fetal hepatocytes were reprogrammed at a frequency over 50-fold higher than adult hepatocytes. Adult hepatocytes were only reprogrammed with six factors, while fetal hepatocytes could be reprogrammed with three (OCT4, SOX2, NANOG) or four factors (OCT4, SOX2, NANOG, LIN28 or OCT4, SOX2, KLF4, C-MYC). The increased reprogramming efficiency of fetal cells was not due to increased transduction efficiency or vector toxicity. These studies confirm that hiPSCs can be generated from adult and fetal hepatocytes including those with genetic diseases. Fetal hepatocytes reprogram much more efficiently than adult hepatocytes, although both could serve as useful sources of hiPSC-derived hepatocytes for basic research or transplantation.

3D Printing of Human Tissue Mimics via Layer-by-Layer Assembly of Polymer/Hydrogel Biopapers

NASA Astrophysics Data System (ADS)

Ringeisen, Bradley

2015-03-01

The foundations of tissue engineering were built on two fundamental areas of research: cells and scaffolds. Multipotent cells and their derivatives are traditionally randomly seeded into sophisticated polymer or hydrogel scaffolds, ultimately with the goal of forming a tissue-like material through cell differentiation and cell-material interactions. One problem with this approach is that no matter how complex or biomimetic the scaffold is, the cells are still homogeneously distributed throughout this three dimensional (3D) material. Natural tissue is inherently heterogeneous on both a microscopic and macroscopic level. It also contains different types of cells in close proximity, extracellular matrix, voids, and a complex vascularized network. Recently developed 3D cell and organ printers may be able to enhance traditional tissue engineering experiments by building scaffolds layer-by-layer that are crafted to mimic the microscopic and macroscopic structure of natural tissue or organs. Over the past decade, my laboratory has developed a capillary-free, live cell printer termed biological laser printing, or BioLP. We find that printed cells do not express heat shock protein and retain >99% viability. Printed cells also incur no DNA strand fracture and preserve their ability to differentiate. Recent work has used a layer-by-layer approach, stacking sheets of hybrid polymer/hydrogel biopapers in conjunction with live cell printing to create 3D tissue structures. Our specific work is now focused on the blood-brain-barrier and air-lung interface and will be described during the presentation.

Production of human CD59-transgenic pigs by embryonic germ cell nuclear transfer

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

Ahn, Kwang Sung; Won, Ji Young; Park, Jin-Ki

Research highlights: {yields} Human CD59 (hCD59) gene was introduced into porcine embryonic germ (EG) cells. {yields} hCD59-transgenic EG cells were resistant to hyperacute rejection in cytolytic assay. {yields} hCD59-transgenic pigs were produced by EG cell nuclear transfer. -- Abstract: This study was performed to produce transgenic pigs expressing the human complement regulatory protein CD59 (hCD59) using the nuclear transfer (NT) of embryonic germ (EG) cells, which are undifferentiated stem cells derived from primordial germ cells. Because EG cells can be cultured indefinitely in an undifferentiated state, they may provide an inexhaustible source of nuclear donor cells for NT to producemore » transgenic pigs. A total of 1980 NT embryos derived from hCD59-transgenic EG cells were transferred to ten recipients, resulting in the birth of fifteen piglets from three pregnancies. Among these offspring, ten were alive without overt health problems. Based on PCR analysis, all fifteen piglets were confirmed as hCD59 transgenic. The expression of the hCD59 transgene in the ten living piglets was verified by RT-PCR. Western analysis showed the expression of the hCD59 protein in four of the ten RT-PCR-positive piglets. These results demonstrate that hCD59-transgenic pigs could effectively be produced by EG cell NT and that such transgenic pigs may be used as organ donors in pig-to-human xenotransplantation.« less

Optimization-based mesh correction with volume and convexity constraints

DOE PAGES

D'Elia, Marta; Ridzal, Denis; Peterson, Kara J.; ...

2016-02-24

In this study, we consider the problem of finding a mesh such that 1) it is the closest, with respect to a suitable metric, to a given source mesh having the same connectivity, and 2) the volumes of its cells match a set of prescribed positive values that are not necessarily equal to the cell volumes in the source mesh. This volume correction problem arises in important simulation contexts, such as satisfying a discrete geometric conservation law and solving transport equations by incremental remapping or similar semi-Lagrangian transport schemes. In this paper we formulate volume correction as a constrained optimizationmore » problem in which the distance to the source mesh defines an optimization objective, while the prescribed cell volumes, mesh validity and/or cell convexity specify the constraints. We solve this problem numerically using a sequential quadratic programming (SQP) method whose performance scales with the mesh size. To achieve scalable performance we develop a specialized multigrid-based preconditioner for optimality systems that arise in the application of the SQP method to the volume correction problem. Numerical examples illustrate the importance of volume correction, and showcase the accuracy, robustness and scalability of our approach.« less