WorldWideScience
1

Plant biomass and stem juice of the C4 sugarcane at elevated growth CO2 and temperature  

Science.gov (United States)

Plant biomass, stem juice and stem sugar were determined for four sugarcane cultivars grown for three months at daytime [CO2] of 360 (ambient) and 720 (doubled) ppm and temperatures (T) of 1.5 (near-ambient) and 6.0C higher than outside ambient T. Leaf area and biomass, stem biomass, stem juice and ...

2

Breast Cancer Stem-Like Cells Are Inhibited by a Non-Toxic Aryl Hydrocarbon Receptor Agonist  

UK PubMed Central (United Kingdom)

BackgroundCancer stem cells (CSCs) have increased resistance to cancer chemotherapy. They can be enriched as drug-surviving CSCs (D-CSCs) by growth with chemotherapeutic drugs, and/or...Full Text Available

3

Stem growth habit affects leaf morphology and gas exchange traits in soybean  

British Library Electronic Table of Contents (United Kingdom)

Backgrounds and Aims The stem growth habit, determinate or indeterminate, of soybean, Glycine max, varieties affects various plant morphological and developmental traits. The objective of this study is to identify the effect of stem growth habit in soybean on the stomatal conductance of single leaves in relation to their leaf morphology in order to better understand the ecological and agronomic significance of this plant trait. Methods The stomatal conductance of leaves on the main stem was measured periodically under favourable field conditions to evaluate gmax, defined as the maximum stomatal conductance at full leaf expansion, for four varieties of soybean and their respective determinate or indeterminate near isogenic lines (NILs). Leaf morphological traits including stomatal density, ...

2009-01-01

4

Growth Promotion in Pea Stem Sections. III. By Alkyl Nitriles, Alkyl Acetylenes and Insect Juvenile Hormones 1  

UK PubMed Central (United Kingdom)

C14, C15, and C16 alkyl nitriles, and C16 and C18 alkyl acetylenes at 10 to 105 micromolar concentrations promote the growth of stem sections from...Full Text Available

1969-07-01

5

The effects of high-intensity pulsed electromagnetic field on proliferation and differentiation of neural stem cells of neonatal rats in vitro.  

Science.gov (United States)

The effects of high-intensity pulsed electromagnetic stimulation (HIPEMS) on proliferation and differentiation of neonatal rat neural stem cells in vitro were investigated. Neural stem cells derived from neonatal rats were exposed to 0.1 Hz, 0.5-10 Tesla (T) [8 groups of B-I, respectively], 5 stimuli of HIPEMF. The sham exposure controls were correspondingly established. Inverted phase contrast microscope was used to observe the cultured cells, MTT assay to detect the viability of the cells as expressed by absorbance (A) value, and flow cytometry to measure differentiation of neural stem cells. The results showed that A values of neural stem cells in both 3.0 T and 4.0 T groups were significantly higher than the other groups 24 to 168 h post HPEMS, indicating a strong promotion of the growth of neural stem cells (PHPEMS groups was the same as that in control ...

2009-12-29

6

Effects of an acute dose of gamma radiation exposure on stem diameter growth, carbon gain, and biomass partitioning in Helianthus annuus  

Energy Technology Data Exchange (ETDEWEB)

Nineteen-day-old dwarf sunflower plants (Helianthus annuus, variety NK894) received a variable dose (0-40 Gy) from a cobalt-60 gamma source. A very sensitive stem monitoring device, developed at Battelle's Pacific Northwest Laboratories, Richland, Washington was used to measure real-time changes in stem diameter. Exposure of plants caused a significant reduction in stem growth and root biomass. Doses as low as 5 Gy resulted in a significant increase in leaf density, suggesting that nonreversible morphological growth changes could be induced by very low doses of radiation. Carbohydrate analysis of 40-Gy irradiated plants demonstrated significantly more starch content in leaves and significantly less starch content in stems 18 days after exposure than did control plants. In contrast, the carbohydrate content in roots of 40-Gy irradiated plants were not ...

1988-05-25

7

Further Studies of the Ability of Xyloglucan Oligosaccharides to Inhibit Auxin-Stimulated Growth 1  

UK PubMed Central (United Kingdom)

The structural features required for xyloglucan oligosaccharides to inhibit 2,4-dichlorophenoxyacetic acid-stimulated elongation of pea stem segments have been investigated. A nonasaccharide (XG9)...Full Text Available

1992-05-01

8

Differentiation of trophoblast stem cells into giant cells is triggered by p57/Kip2 inhibition of CDK1 activity  

UK PubMed Central (United Kingdom)

Genome endoreduplication during mammalian development is a rare event for which the mechanism is unknown. It first appears when fibroblast growth factor 4 (FGF4) deprivation induces differentiation...Full Text Available

2008-11-01

9

Zebrafish embryo extracts promote sphere-forming abilities of human melanoma cell line  

British Library Electronic Table of Contents (United Kingdom)

Sphere-forming abilities in culture condition are considered a hallmark of cancer stem-like cells, which represents tumor cell invasiveness and stem-like characteristics. We aimed to show that the sphere-forming subpopulation of human malignant melanoma cell line WM-266-4 acts differently to zebrafish embryo extracts compared with their bulk counterpart. Spheres were maintained in neural stem cell culture conditions. The embryos of zebrafish at specific developmental stages were collected and the extracts were purified under 100 kDa. Spheres were treated with embyo extracts and proliferation assay and immunocytochemistry were conducted. Spheroid cells expressed nestin and epidermal growth factor receptor (EGFR) but not melanoma antigen recognized by T-cells (MART)1, indicating their stem-l...

2009-01-01

10

Inhibition of prepenetration processes of the powdery mildew Golovinomyces orontii on host inflorescence stems is reduced in the Arabidopsis cuticular mutant cer3 but not in cer1  

British Library Electronic Table of Contents (United Kingdom)

The obligate biotrophic fungus Golovinomyces orontii causes powdery mildew (PM) disease on its host Arabidopsis thaliana. Most research on the G. orontii?Arabidopsis pathosystem uses rosette leaves as experimental materials, so little is known about the behavior of G. orontii on other Arabidopsis organs. We thus conducted microscopic analyses of the PM infection process on leaves, stems, fruits and roots of Arabidopsis. Adaxial and abaxial surfaces of mature rosette leaves supported G. orontii infection, but growth was somewhat suppressed on cauline leaves. Prepenetration processes (germination and appressorium formation) were strongly inhibited on stems, fruits and roots. To test the effect of alterations in the Arabidopsis cuticle on the inhibition of prepenetration processes on stems, w...

2011-01-01

11

Cryopreservation of isolated blastomeres and embryonic stem-like cells of Leopard danio, Brachydanio frankei  

British Library Electronic Table of Contents (United Kingdom)

Abstract This study aimed at developing a suitable cryopreservation protocol for embryonic stem (ES)-like cells of a tiny freshwater fish Leopard danio (Brachydanio frankei). Embryonic stem (ES)-like cells derived from blastomeres of the early blastulae stage of the developing embryo were cultured in vitro in a medium containing Leibowitz-15 supplemented with 10% foetal bovine serum, leopard danio embryo extract, sodium bicarbonate, sodium selenite, basic fibroblast growth factor, epidermal growth factor and leukaemia inhibitory factor. The ES-like cells showed properties similar to ES cells in other species. They were morphologically small, round to polygonal and present in patches and extensively expressed alkaline phosphatase and stage-specific embryonic antigen. The toxicity and chilli...

2010-01-01

12

Fire Regimes and Tree Growth in Low Rainfall Jarrah Forest of South-west Australia  

British Library Electronic Table of Contents (United Kingdom)

Regular fuel reduction burning is an important management strategy for reducing the scale and intensity of wildfires in south-west Australian native forests, but the long term effects of this on tree and stand growth are not well understood. Five fire treatments, including application of frequent and infrequent low intensity burns, and 25?years of fire exclusion, were applied to small (4?ha) experimental plots in a low rainfall mixed jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) forest to investigate the effects of these treatments on tree stem diameter growth, stand basal area increment and tree mortality. Mean tree stem growth measured over 20?years was lowest in the long unburnt treatment compared with the burn treatments, although surface soil nutrient levels were gener...

2010-01-01

13

Replication-defective vectors of reticuloendotheliosis virus transduce exogenous genes into somatic stem cells of the unincubated chicken embryo  

Energy Technology Data Exchange (ETDEWEB)

Replication-defective vectors derived from reticuloendotheliosis virus were used to transduce exogenous genes into early somatic stem cells of the chicken embryo. One of these vectors transduced and expressed the chicken growth hormone coding sequence. The helper cell line, C3, was used to generate stocks of vector containing about 10/sup 4/ transducing units per ml. Injection of 5- to 20-..mu..l volumes of vector directly beneath the blastoderm of unincubated chicken embryos led to infection of somatic stem cells. Infected embryos and adults contained unrearranged integrated proviral DNAs. Embryos expressed the transduced chicken growth hormone gene and contained high levels of serum growth hormone. Blood, brain, muscle, testis, and semen contained from individuals injected as embryos contained vector DNA. Replication-defective vectors of the reticuloendotheliosis virus transduced ...

1989-06-01

14

Collective acceleration of electrons and ions in a high current relativistic electron beam. Final report  

International Nuclear Information System (INIS)

The original purpose of this research was an investigation into the use of slow space charge waves on weakly relativistic electron beams for ion acceleration. The work had three main objectives namely, the development of a suitable ion injector, the growth and study of the properties of slow space charge waves on an electron beam, and a combination of the two components parts into a suitable proof of principle demonstration of the wave accelerator. This work focusses on the first two of these objectives.

15

Transforming Growth Factor-b Induces Differentiation of the Labyrinthine Trophoblast Stem Cell Line SM10  

British Library Electronic Table of Contents (United Kingdom)

The mammalian placenta consists of different trophoblast cell types that assist in the variety of functions required for the maintenance of pregnancy. In rodents, labyrinthine trophoblasts of the placenta are especially important, because they are capable of differentiating into fused labyrinthine cells, which form the feto-maternal exchange surface. Even though the molecular signals triggering labyrinthine trophoblast differentiation are poorly understood, transforming growth factor-b (TGF-b) has been shown to be present in the placental environment and alter trophoblast development. In this study, we investigated the effects of TGF-b on the differentiation of the labyrinthine trophoblast stem cell lines SM10 and HRP-1. RT-PCR analyses demonstrated that while the molecular expression of l...

2005-01-01

16

The endophytic fungi from wheat (Triticum aestivum L.)  

British Library Electronic Table of Contents (United Kingdom)

In order to study the species composition of endophytes from wheat healthy plants in Buenos Aires Province (Argentina) and to determine their infection frequencies from leaves, stems, glumes and grains, wheat plants were collected from five cultivars at five growth stages from crop emergence to harvest. A total of 1,750 plant segments (leaves, stems, glumes and grains) were processed from the five wheat cultivars at five growth stages, and 722 isolates of endophytic fungi recovered were identified as 30 fungal genera. Alternaria alternata, Cladosporium herbarum, Epicoccum nigrum, Cryptococcus sp., Rhodotorula rubra, Penicillium sp. and Fusarium graminearum were the fungi that showed the highest colonization frequency (CF%) in all the tissues and organs analysed. The number of taxa isolated...

2007-01-01

17

Rooting of hybrid clones of Populus tremula L. x P. tremuloides Michx. by stem cuttings derived from micropropagated plants  

Energy Technology Data Exchange (ETDEWEB)

Propagation costs could be cut by replacing part of the micropropagation process with steps involving more traditional techniques. This study explored possibilities for improving existing vegetative propagation techniques for aspen using stem cuttings obtained from micropropagated plants. Vegetative propagation through stem cuttings was studied in 10 micropropagated hybrid aspen clones (Populus tremula L. x P. tremuloides Michx). Cuttings containing one axillary bud were harvested from the same donor plants twice during the growing season: the first harvest in May and the second harvest in July. Rooting percentage was correlated positively with root length, number of roots and height of cutting plant but negatively with length of rooting. The average rooting percentage was 53% in the first harvest and 27% in second harvest. Indole-3-butyric acid treatments (1.2 mM) significantly improved rooting in the second harvest, but not in the first ...

2001-07-01

18

Genetic and somatic effects in animals maintained on tritiated water  

Energy Technology Data Exchange (ETDEWEB)

The possible genetic (dominant lethal mutations (DLM) and cytogenetic changes in the regenerating liver) and somatic (hematopoietic stem cell changes, growth and nonspecific life time shortening) effects in mice maintained on tritiated water (HTO) over two generations was investigated. Results to date are summarized. (ACR)

1981-01-01

19

Rapid vegetative propagation of conifers  

Energy Technology Data Exchange (ETDEWEB)

Factors influencing the rooting-potential of stem cuttings of conifers were studied for the purpose of improving methods of rapid vegetative propagation. Within the bounds of hereditary limits, root regeneration depends, to a considerable extent, on the qualities of rooting-media, date of cutting excision, age and physiological conditions of the stock plant, age of the cutting-wood, its position on the plant, and chemical treatment. Hardwood cuttings, which have a relatively high content of endogenous auxin and carbohydrates, and morphological root initials, gave the best results. This method made it possible to increase the growth rate of cuttings 2.5-5 times that of cuttings taken from shoots of current growth. (Refs. 21).

1981-04-01

20

Increased M?ller Cell De-Differentiation After Grafting of Retinal Stem Cell in the Sub-Retinal Space of Royal College of Surgeons Rats  

British Library Electronic Table of Contents (United Kingdom)

In several vertebrate classes, the M?ller glia are capable of de-differentiating, proliferating, and acquiring a progenitor-like state in response to acute retinal injury or in response to exogenous growth factors. Our previous study has shown that M?ller cells can be activated and de-differentiated into retinal progenitors during Royal College of Surgeons (RCS) rats' degeneration, although the limited proliferation cannot maintain retinal function. We now report that rat retinal stem cells (rSCs) transplanted into RCS rats slowed the progression of retinal morphological degeneration and prevented the functional disruption. Further, we found that retinal progenitor cells labeled with Chx10 were increased significantly after rSCs transplantation, and most of them are mainly from activated M...

2011-01-01

21

Greater than the sum of their parts: Combination strategies for immune regeneration following allogeneic hematopoietic stem cell transplantation  

British Library Electronic Table of Contents (United Kingdom)

Cytoreductive conditioning regimes designed to allow for successful allogeneic hematopoietic stem cell transplantation (allo-HSCT) paradoxically are also detrimental to recovery of the immune system in general but lymphopoiesis in particular. Post-transplant immune depletion is particularly striking within the T cell compartment which is exquisitely sensitive to negative regulation, evidenced by the profound decline in thymic function with age. As a consequence, regeneration of the immune system remains a significant unmet clinical need. Over the past decade studies have revealed several promising therapeutic strategies to address ineffective lymphopoiesis and post-transplant immune deficiency. These include the use of cytokines such as IL-7, IL-12 and IL-15; growth factors and hormones li...

2011-01-01

22

Effect of spacing and nitrogen fertilization on the establishment and biomass production of short rotation Poplar in Finland  

Energy Technology Data Exchange (ETDEWEB)

Short rotation trials using cuttings poplar (Populus x rasumowskyana) in Southern Finland investigated the establishment of poplar plantations and the effects of spacing and application of nitrogen fertilizer on biomass production over a period of 6 years. Thicker cuttings grew better whilst those of less than 1 cm diameter grew only moderately. Nitrogen fertilization improved height and diameter growth and above-ground dry mass yield. Woody biomass production was 4.2 dry tons/ha per year, at 300 kg/ha nitrogen. A spacing of 15 000 stems/ha gave the best yield after 4 years, but 5000 stems/ha was more productive spacing in the next 2 years. (author).

1989-01-01

23

Age determination of large live trees with inner cavities: radiocarbon dating of Platland tree, a giant African baobab  

British Library Electronic Table of Contents (United Kingdom)

? Introduction For large trees without a continuous sequence of growth rings in their trunk, such as the African baobab (Adansonia digitata L.), the only accurate method for age determination is radiocarbon dating. As of today, this method was limited to dating samples collected from the remains of dead specimens. ? Methods Our research extends significantly the dating of such trees to large live specimens with inner cavities. The new approach is based on collecting samples from the cavities and their subsequent radiocarbon dating. ? Results The giant two-stemmed Platland tree, also known as Sunland baobab, was investigated by using this new approach. AMS radiocarbon dates of the oldest sample segments originating from the two inner cavities indicate that the large stem I (364.5?m3) is 750...

2011-01-01

24

Development of functional foods for radiation workers  

Energy Technology Data Exchange (ETDEWEB)

In searching modulators of immunity and hematopoiesis among natural products, being used as foods, six herbs exhibited lymphocyte proliferation in vitro, and six exhibited augmentation of hematopoietic cell growth. The combined treatments showed synergistic effects of lymphocyte proliferation and of hematopoietic cell growth. On the other hand, we found four effective oriental medicinal prescriptions, used as energy tonic or blood-building decoctions, for survival and regeneration of hematopoietic cells and for protection of stem cells of intestinal crypt in irradiated mice. On the basis of these results, extracts from combinations of herbs were made in expectation of higher effects in the three respects. In immuno modulation activity by the two combinations of herbs was confirmed in mice. In culture of bone narrow cells, growth improvement of non-adherent precursor and induction of cytokine expression ...

2000-03-01

25

Stem cells: Research tools and clinical treatments  

British Library Electronic Table of Contents (United Kingdom)

Abstract The term -stem cell- most commonly refers to embryonic stem cells, particularly in the lay media; however, it also describes other cell types. A stem cell represents a cell of multi-lineage potential with the ability for self-renewal. It is now clear that the plasticity and immortality of a given stem cell will depend on what type of stem cell it is, whether an embryonic stem cell, a fetal-placental stem cell or an adult stem cell. Stem cells offer great promise as cell-based therapies for the future. With evolving technology, much of the socio-political debate regarding stem cells can now be avoided.

2011-01-01

26

Analysis of beam emittance in FEL (Free Electron Laser)  

International Nuclear Information System (INIS)

To achieve high efficiency for the conversion of electron kinetic energy in an electron beam to electromagnetic energy in a Free Electron Laser (FEL), it is important to improve the beam quality. And hence, it is necessary to study and minimize the emittance growth of the beam. According to the requirements for the beam quality in an FEL, the author analyzed the emittance growth caused by the jump of the electric field in an accelerator, energy increase, wakefield in a waveguide, space charge effect and distribution of particles in a beam as well as the wakefield in a deflect system etc. The author also estimated the emittance change caused by the variation of the microwave field from the gun to the first accelerator for such case.

27

Physiological and antioxidant responses of Mentha pulegium (Pennyroyal) to salt stress  

British Library Electronic Table of Contents (United Kingdom)

Mentha pulegium L. is a medicinal and aromatic plant belonging to the Labiatae family present in the humid to the arid bioclimatic regions of Tunisia. We studied the effect of different salt concentrations on plant growth, mineral composition and antioxidant responses. Physiological and biochemical parameters were assessed in the plant organs after 2?weeks of salt treatment with 25, 50, 75 and 100?mM NaCl. Results showed that, growth was reduced even by 25?mM, and salt effect was more pronounced in shoots (leaves and stems) than in roots. This growth decrease was accompanied by a restriction in tissue hydration and K+ uptake, as well as an increase in Na+ levels in all organs. Considering the response of antioxidant enzymes to salt, leaves and roots reacted differently to saline conditions...

2010-01-01

28

Growth dynamics and biomass production in short-rotation poplar plantations: 6-year results for three clones at four spacings  

Energy Technology Data Exchange (ETDEWEB)

Growth dynamics and biomass production in short-rotation poplar plantations were evaluated at Hanyuan Forestry Farm, Baoying County, P.R.C. Experimental treatments applied in a split-plot design included: four planting densities (1111, 833, 625 and 500 stems ha{sup -1}); three poplar clones (NL-80351, I-69 and I-72) and three rotation lengths. Survival of all three clones was excellent at the experimental site under the imposed management regime. Differences in DBH, height, LAI and above-ground biomass production, however, were manifested among the treatments. Overall the clonal ranking was in the order NL-80351 {>=}I-69 > I-72 by age 6. LAI values ranged from 0.6 to 4.4 m{sup 2} m{sup -2} and differences among four planting densities and three clones were significant throughout the first six years. Above-ground biomass productivity was affected considerably by planting density, clone and rotation length. Within the four ...

1999-07-01

29

Regression of rat mammary tumors associated with suppressed growth hormone.  

Science.gov (United States)

Serum growth hormone (GH) was suppressed in female rats bearing mammary tumors induced by 7, 12, dimethylbenz(a)anthracene (DMBA) or N-nitrosomethylurea(NMU). Serum GH was suppressed due to treatment with a human GH analog produced by the plerocercoid stage of the tapeworm Spirometra mansonoides. Rats treated with plerocercoid growth factor (PGF) via plerocercoid infection had accelerated growth rates despite marked reductions in GH levels. Approximately two-thirds of the mammary tumors induced by either DMBA or NMU regressed during three weeks of exposure to PGF while most of the control tumors continued to grow. The data support an important regulatory role for GH in growth of mammary tumors in rats. PMID:3019224

30

Magnetic resonance imaging of the pediatric brain  

International Nuclear Information System (INIS)

The atlas presents sequences of MRI sections parallel to the orbito-meatal plane in children from birth through the age of sixteen years. Each child was studied horizontally and sagitally and three-dimensional brain images were reconstructed to facilitate accurate identification of sulci and gyri. The images show crucial aspects of brain development such as the constancy of the brain stem and primitive brain from birth onward; the development of the telencephalon, characterized by deepening of sulci and growth of the cerebral cortex surface; and the different stages of white matter myelinization.

31

Pigpen, a nuclear coiled body component protein, is involved in angiogenesis  

British Library Electronic Table of Contents (United Kingdom)

We previously reported that puromycin-insensitive leucyl-specific aminopeptidase (PILSAP) is required for vascular endothelial growth factor (VEGF)- and basic fibroblast growth factor (bFGF)-induced angiogenesis and for endothelial differentiation from embryonic stem (ES) cells via the aminopeptidase activity of PILSAP. In this study, we searched for molecules that function during angiogenesis with PILSAP. We performed proteome analysis of nuclear extracts from embryoid bodies (EBs) made from ES cells transfected with mutant PILSAP lacking aminopeptidase activity and mock EBs. We identified pigpen, a 67-kDa nuclear coiled body component protein. Immunoprecipitation and western blotting demonstrated the binding of PILSAP and pigpen in endothelial cells (ECs), and this interaction was enhanc...

2010-01-01

32

Entropy and Hausdorff Dimension in Random Growing Trees  

CERN Document Server

We investigate the limiting behavior of random tree growth in preferential attachment models. The tree stems from a root, and we add vertices to the system one-by-one at random, according to a rule which depends on the degree distribution of the already existing tree. The so-called weight function, in terms of which the rule of attachment is formulated, is such that each vertex in the tree can have at most K children. We define the concept of a certain random measure mu on the leaves of the limiting tree, which captures a global property of the tree growth in a natural way. We prove that the Hausdorff and the packing dimension of this limiting measure is equal and constant with probability one. Moreover, the local dimension of mu equals the Hausdorff dimension at mu-almost every point. We give an explicit formula for the dimension, given the rule of attachment.

2010-01-01

33

Analysis and assay of flavonoid content in the vegetative and reproductive organs of the showy tick trefoil  

British Library Electronic Table of Contents (United Kingdom)

We report here a many-year study of the qualitative and quantitative content of flavonoids in the reproductive organs of the showy tick trefoil (Desmodium canadense (L.) DC., Fabaceae) - stems, leaves, buds, inflorescences,pods, and seeds - collected at different phases of growth at the Department of Medicinal Plants, Kaunas Botanical Garden, Vytautas Magnus University. HPLC studies identified 15 aglycone and glycoside flavonoids: apigenin, apigenin-7-O-glycoside, luteolin, rutin, vicenin-2, vitexin, isovitexin, vitexin rhamnoside, orientin, homoorientin, quercetrin, quercetin, hyperoside, astralagin, and kaempferol. The largest quantities of flavonoids in the vegetative organs from year 2 to year 4 of plant growth were present in the leaves (2.64% and 2.61% at budding and flowering in the...

2011-01-01

34

An Accurate Numerical Solution to the Kinetics of Breakable Filament Assembly  

CERN Document Server

Proteinaceous aggregation occurs through self-assembly-- a process not entirely understood. In a recent article [1], an analytical theory for amyloid fibril growth via secondary rather than primary nucleation was presented. Remarkably, with only a single kinetic parameter, the authors were able to unify growth characteristics for a variety of experimental data. In essence, they seem to have uncovered the underlying allometric laws governing the evolution of filament elongation simply from two coupled non-linear ordinary differential equations (ODEs) stemming from a master equation. While this work adds significantly to our understanding of filament self-assembly, it required an approximate analytical solution representation. Here, we show that the same results are found by purely numerical means once a straightforward and reliable numerical solution to the set of ODEs has been established.

2010-01-01

35

Of Microenvironments and Mammary Stem Cells  

UK PubMed Central (United Kingdom)

In most adult tissues there reside pools of stem and progenitor cells inside specialized microenvironments referred to as niches. The niche protects the stem cells from inappropriate expansion...Full Text Available

2007-06-01

36

Functional Characterization of Melanocyte Stem Cells in Hair Follicles.  

Science.gov (United States)

In mice, coat pigmentation requires a stem cell (SC) system in which the survival, proliferation, and differentiation of melanocytes (MCs) are regulated by microenvironments in hair follicles (HFs). In vitro systems are required to analyze the behavior of single melanocyte stem cells (MCSCs) and their potential to form SC systems in vivo. We describe here an experimental system for the isolation, self-renewal, and differentiation of MCSCs, as well as an in vivo reconstitution assay for assessing their potential. Using Dct(tm1(Cre)Bee)/CAG-CAT-GFP mice, we show that, in the presence of stem cell factor and basic fibroblast growth factor and the XB2 feeder cell line, purified MCSCs can undergo clonogenic proliferation, resulting in c-Kit(low) side scatter(low) cells. In culture, these cells maintain their capacity to differentiate and reconstitute an MCSC system in HFs. As these cells are present in the ...

2011-07-14

37

3 CFR - Guidelines for Human Stem Cell Research  

Science.gov (United States)

...false Guidelines for Human Stem Cell Research Presidential Documents ...2009 Guidelines for Human Stem Cell Research Memorandum for the Heads...scientifically worthy human stem cell research, including human...

2010-01-01

38

Generation of human cortical neurons from a new immortal fetal neural stem cell line  

International Nuclear Information System (INIS)

Isolation and expansion of neural stem cells (NSCs) of human origin are crucial for successful development of cell therapy approaches in neurodegenerative diseases. Different epigenetic and genetic immortalization strategies have been established for long-term maintenance and expansion of these cells in vitro. Here we report the generation of a new, clonal NSC (hc-NSC) line, derived from human fetal cortical tissue, based on v-myc immortalization. Using immunocytochemistry, we show that these cells retain the characteristics of NSCs after more than 50 passages. Under proliferation conditions, when supplemented with epidermal and basic fibroblast growth factors, the hc-NSCs expressed neural stem/progenitor cell markers like nestin, vimentin and Sox2. When growth factors were withdrawn, proliferation and expression of v-myc and telomerase were dramatically reduced, and the hc-NSCs differentiated into glia ...

2007-02-01

39

Stem Cell Research Policy Lesson Plan  

Science.gov (United States)

Students get a background on Stem Cell technology and learn to write an effective opinion essay.

2007-09-25

40

A bright field scanning transmission electron microscope (STEM ...  

Science.gov (United States)

A bright field scanning transmission electron microscope (STEM) micrograph showing a Wassonite grain in dark contrast. ...

41

Surface-loss power calculations for the LANSCE DTL  

Energy Technology Data Exchange (ETDEWEB)

The surface losses in the drift-tube linac (DTL) tanks 3 and 4 of the LANSCE linear accelerator are calculated using 3-D electromagnetic modeling with the CST MicroWave Studio (MWS). The results are used to provide more realistic power estimates for the 201.25MHz RF upgrade design within the LANSCE-R project. We compared 3-D MWS results with those from traditional 2-D Superfish computations for DTL cells and their simplified models and found differences on the level of a few percent. The differences are traced to a 3-D effect consisting in a redistribution of the surface currents on the drift tubes (DT) produced by the DT stem. The dependence of MWS results on the mesh size used in computations is also discussed.

2008-01-01

42

Standing-Wave Free-Electron Laser Two-Beam Accelerator  

Energy Technology Data Exchange (ETDEWEB)

A free-electron laser (FEL) two-beam accelerator (TBA) is proposed, in which the FEL interaction takes place in a series of drive cavities, rather than in a waveguide. Each drive cavity is 'beat-coupled' to a section of the accelerating structure. This standing-wave TBA is investigated theoretically and numerically, with analyses included of microwave extraction, growth of the FEL signal through saturation, equilibrium longitudinal beam dynamics following saturation, and sensitivity of the microwave amplitude and phase to errors in current and energy. It is found that phase errors due to current jitter are substantially reduced from previous versions of the TBA. Analytic scalings and numerical simulations are used to obtain an illustrative TBA parameter set.

1991-02-01

43

HTSC devices fabricated by selective epitaxial growth  

International Nuclear Information System (INIS)

The use of a selective epitaxial growth technique for fabricating YBCO thin-film microstructures is described. No film post-deposition processing is required; hence damage to the structure is minimized. The technique is compatible with a passivation process to protect the structure without exposure to air. The microbridges, Josephson junctions and rf SQUIDs protected by an amorphous YBCO passivation have long lifetime even after severe accelerated aging tests. Rf SQUIDs fabricated by this technique show a significant reduction of low-frequency noise when operating in weak magnetic fields compared with SQUIDs fabricated by the conventional ion beam etching technique. (author)

1999-04-01

44

Determination of a various ions such as alkali metals in leaves, stems, roots and seeds of the radish and their distribution  

Energy Technology Data Exchange (ETDEWEB)

Determination, uptake and distribution of various ions such as alkali metals in three different parts (leaf, stem and root) and seeds of radish (Kaiware daikon) were examined using flame emission spectrometry and ICP-AES. In order to examine the influence of concentration alkali metal ion concentration in the radish culture solution on the uptake and distribution of these metals, the radish was grown at pH 5.6 in solutions containing alkali metal chloride at concentrations ranging from 10{sup -5} to 10{sup -1} mol dm{sup -3}. When the radish were grown in culture solution with alkali metal ions of low concentrations (10{sup -5} and 10{sup -4} mol dm{sup -3}), Na, K, Rb and trace Li were detected in leaves, stems and roots while Cs was scarcely detected. However, the contents of Na, K, Li in these organs were the same as those in radish cultivated in pure water. An increase of Rb uptake was observed with an increased Rb concentration. In the ...

1995-05-01

45

Pitting corrosion of metals: A review of the critical factors  

Energy Technology Data Exchange (ETDEWEB)

Pitting corrosion is localized accelerated dissolution of metal that occurs as a result of a breakdown of the otherwise protective passive film on the metal surface. This paper provides an overview of the critical factors influencing the pitting corrosion of metals. The phenomenology of pitting corrosion is discussed, including the effects of alloy composition, environment, potential, and temperature. A summary is then given of studies that have focused on various stages of the pitting process, including breakdown of the passive film, metastable pitting, and pit growth. 120 refs.

1998-06-01

46

Functions of mammalian Cdc7 kinase in initiation/monitoring of DNA replication and development  

Energy Technology Data Exchange (ETDEWEB)

Cdc7 kinase plays an essential role in firing of replication origins by phosphorylating components of the replication complexes. Cdc7 kinase has also been implicated in S phase checkpoint signaling downstream of the ATR and Chk1 kinases. Inactivation of Cdc7 in yeast results in arrest of cell growth with 1C DNA content after completion of the ongoing DNA replication. In contrast, conditional inactivation of Cdc7 in undifferentiated mouse embryonic stem (ES) cells leads to growth arrest with rapid cessation of DNA synthesis, suggesting requirement of Cdc7 functions for continuation of ongoing DNA synthesis. Furthermore, loss of Cdc7 function induces recombinational repair (nuclear Rad51 foci) and G2/M checkpoint responses (inhibition of Cdc2 kinase). Eventually, p53 becomes highly activated and the cells undergo massive p53-dependent apoptosis. Thus, defective origin activation in mammalian cells can generate DNA replication ...

2003-11-27

47

Accelerator technology program. Progress report, April-December 1978  

Science.gov (United States)

This report presents highlights of activities in the Acceleartor Technology (AT) Division from April through December 1978. The report is divided into 10 sections to cover work done by the four groups that make up AT Division (AT-1, AT-2, AT-3, and AT-4). Section I is a brief summary of the whole report. Sections II through VI describe work done by At-1, the Linac Technology Group. Subjects covered are the Pion Generation for Medical Irradiation Program, the Electronuclear Fuel-Producing Accelerator Program, the Gyrocon rf Amplifier Program, the Electron Linear Accelerator Program, and the Free Electron Laser Program. Section VII covers the Linear Accelerator Beam Dynamics development, and Sec. VIII deals with work with the H/sup -/ Ion Source. Most of the work in Secs. VII and VIII was done by AT-2, the Special Projects Group, although work on factors influencing emittance growth was done by MP-9, and ...

1980-05-01

48

PKH26 as a fluorescent label for live human umbilical mesenchymal stem cells  

British Library Electronic Table of Contents (United Kingdom)

To determine whether PKH26 labeling affects the morphologies, phenotypes, proliferation, and secretion abilities of human umbilical mesenchymal stromal cells (HUMSCs) were investigated. Isolated HUMSCs were labeled with PKH26, and cell morphology was observed under microscope. Cell cycle, apoptotic cell death, expression of PKH26, and the proliferation rate were evaluated. Additionally, fluorescence intensity of PKH26 labeling at different passage times was quantified. There were no detectable differences in cell morphology, cell growth, and proliferation rate after PKH26 labeling. In addition, fluorescence intensity of PKH26 labeling was gradually reduced with increase of the passage times. The PKH26 labeling disappeared after passage six times. In summary, PKH26 labeling is a safe and ef...

2011-01-01

49

Improving protein quality of soybean through induced mutations  

International Nuclear Information System (INIS)

Soybean is one of the most economical and nutritious food packed with basic nutrients that combat diseases stemming from mal- and under-nutrition. Despite its rich nutritional profile, use of soybean in food has been limited because soybean proteins are often associated with compounds, which could exert a negative impact on the nutritional quality of the protein. Trypsin inhibitor (TI) is one of the important anti-nutritional factors that exert negative effect by causing growth inhibition. Soybean cultivar VLS-2 was irradiated with 250 Gy gamma rays in a gamma cell (200) with 60Co source installed at BARC to induce mutations for low trypsin inhibitor content. Three mutants with lower levels of TI content were identified and can be utilized for developing elite varieties of soybean. (author)

2011-02-22

50

Education for All in Latin America in the Twenty-First Century: The Challenges of Jomtien. Development Discussion Paper No. 358.  

Science.gov (United States)

A declaration for achieving universal basic education adopted by the World Conference on Education for All in Jomtien, Thailand, as it relates to Latin America is discussed in this paper. The document then offers an examination of educational expansion in Latin America, a discussion of disproportionate educational budget cuts, and an analysis of challenges that stem from two trends: (1) the growing gap between population growth and educational expansion; and (2) low educational quality and high repetition rates. Proposals are offered for major, gradual educational reforms based on an increased level of fiscal resources, and a change in resource management responsive to economic needs. The major obstacle to implementation is argued to be the political economy of education and of adjustment. International support of local initiatives is important in achieving basic educational equity. (33 references) (LMI)

1990-09-01

51

Effect of forced convection by accelerating crucible rotation on directional solidification  

Energy Technology Data Exchange (ETDEWEB)

An accelerated crucible rotation (ACR) technique was applied to the Bridgman (B) directional solidification of Al-Cu hypoeutectic and eutectic alloys. For Al-4.5% Cu hypoeutectic alloys. The development of dendrites was prevented and the cellular spacing was reduced by forced convection in the ACR-B process. For the Al-CuAl{sub 2} eutectic alloy, maximum rotation rates of 100, 200, 300 and 400 rpm were adopted, and the growth rate R was varied between 5 and 60 {mu}m/s. The results show that the periodic structure related to the crucible rotation periods occurs when the Reynold's number Re > 500, and that the average eutectic spacing decreases with the increase of Re. It is found that the convection increases the temperature gradient in front of the liquid/solid interface and reduces the depth of the concave interface, depending on Re and R. The convection also changes the solute distribution around the tips of the cells or ...

2001-05-01

52

Structure and kinetics of Sn whisker growth on Pb-free solder finish  

Energy Technology Data Exchange (ETDEWEB)

Standard Leadframes used in surface mount technology are finished with a layer of eutectic SnPb for passivation and for enhancing solder wetting during reflow. When eutectic SnPb is replaced by Pb-free solder, especially the eutectic SnCu, a large number of Sn whiskers are found on the Pb-free finish. Some of the whiskers are long enough to become shorts between the neighboring legs of the leadframe. How to suppress their growth and how to perform accelerated test of Sn whisker growth are crucial reliability issues in the electronic packaging industry. In this paper, we report the study of spontaneous Sn whisker growth at room temperature on eutectic SnCu and pure Sn finishes. Both compressive stress and surface oxide on Sn are necessary conditions for whisker growth. Structure and stress analyses by using the micro-diffraction in synchrotron radiation are reported. Cross-sectional ...

2002-07-11

53

Microstructure fracture toughness and fatigue crack growth rate in titanium alloys; Proceedings of the 1987 TMS-AIME Annual Symposium, Denver, CO, Feb. 24, 25, 1987  

Science.gov (United States)

The papers contained in this volume provide an overview of recent theoretical and experimental research related to the fracture toughness and fatigue crack growth characteristics of titanium alloys. Topics discussed include room temperature fatigue crack propagation in beta-titanium alloys, fatigue crack growth rate acceleration in alpha+beta Ti alloys, influence of transformed beta microstructures on fatigue crack growth rates in Ti-6Al-4V, and the role of inclusion and pore content on the fracture toughness of powder processed blended elemental Ti-10V-2Fe-3Al. Papers are also presented on fatigue crack growth measurements in an alpha-beta titanium alloy, the effects of thermal processing variation on the properties of Ti-6Al-4V, and the effect of microstructure on ductility and fracture toughness of alpha+beta titanium alloys.

1987-01-01

54

Variations in humanized and defined culture conditions supporting derivation of new human embryonic stem cell lines  

DEFF Research Database (Denmark)

The evolution of "humanized" (i.e., free of animal sourced reagents) and ultimately chemically defined culture systems for human embryo stem cell (hESC) isolation and culture is of importance to improving their efficacy and safety in research and therapeutic applications. This can be achieved by integration of a multitude of individual approaches to replace or eliminate specific animal sourced reagents into a single comprehensive protocol. In the present study our objective was to integrate strategies obviating reliance on some of the most poorly defined and path-critical factors associated with hESC derivation, namely the use of animal immune compliment to isolate embryo inner cell mass, and animal sourced serum products and feeder cells to sustain hESC growth and attachment. As a result we report the derivation of six new hESC lines isolated by outgrowth from whole blastocysts on an extracellular matrix substrate of purified human laminin ...

2006-01-01

55

Machinery management data for willow harvest with a bio-baler  

Energy Technology Data Exchange (ETDEWEB)

Willow harvested in 2-to-3-year rotations has been touted as a reliable source of biomass. A newly designed harvester based on a round baler was developed in 2006. The third generation biobaler was evaluated in 2009 at 2 willow plantations in Quebec. The first site at Godmanchester was a three-year old regrowth with an estimated 52,000 stems/ha of large diameter willow. The biobaler with a flail cutter harvested three plots totalling 4,136 m{sup 2}. Total harvested biomass was 10.36 t DM in 42 bales. The harvest rate averaged 29 bale/h with an average bale size of 1.22 m wide by 1.30 m in diameter. Diesel fuel consumption averaged 0.81 L/bale. Measured losses averaged 11 per cent of the yield. The second site at Saint-Roch-del'Achigan was a two-year old growth with an estimated 49,000 stems/ha of large stem willow. The biobaler harvested seven plots totalling 15,740 m{sup 2}. Total harvest was ...

2010-07-01

56

Stem Cell Research Policies around the World  

UK PubMed Central (United Kingdom)

The proliferation of stem cell research, conflated with its ethical and moral implications, has led governments to attempt regulation of both the science and funding of stem cells. Due to a diversity...Full Text Available

2009-09-01

57

SELF-RENEWAL AND DIFFERENTIATION OF MOUSE EMBRYONIC STEM CELLS AS MEASURED BY Oct4 GENE EXPRESSION: EFFECTS OF LIF, ...  

Science.gov (United States)

... from Dr. Austin Smith of the Institute for Stem Cell Research, University of Edinburgh) was modified from the CGR8 ... to thank Dr. Austin Smith, the Institute for Stem Cell Research, University of Edinbu...

58

Progress with Nonhuman Primate Embryonic Stem Cells1  

Science.gov (United States)

... based, disease treatment remains promising, the emphasis for stem cell research from the biomedical research community is clear, and ... diagnosis as a novel source of embryos for stem cell research. Repr...

59

Nucleoside Drugs Induce Cellular Differentiation by Caspase-Dependent Degradation of Stem Cell Factors  

UK PubMed Central (United Kingdom)

BackgroundStem cell characteristics are an important feature of human cancer cells and play a major role in the therapy resistance of tumours. Strategies to target cancer stem cells...Full Text Available

60

Induced pluripotent stem cells, new tools for drug discovery and new hope for stem cell therapies  

UK PubMed Central (United Kingdom)

Somatic cell nuclear transfer or therapeutic cloning has provided great hope for stem cell-based therapies. However therapeutic cloning has been experiencing both ethical and technical difficulties....Full Text Available

2009-01-01

61

Human hair genealogies and stem cell latency  

UK PubMed Central (United Kingdom)

BackgroundStem cells divide to reproduce themselves and produce differentiated progeny. A fundamental problem in human biology has been the inability to measure how often stem cells...Full Text Available

62

Human Cloning  

Science.gov (United States)

... is known as "reproductive cloning." The Link to Stem Cell Research Stem cell research and research cloning are closely linked. Scientists in ... to arrive at a position on cloning and stem cell research. Many nations, including the UK, China, and South ...

63

Function of mesenchymal stem cells following loading of gold nanotracers  

UK PubMed Central (United Kingdom)

Background:Stem cells can differentiate into multiple cell types, and therefore can be used for cellular therapies, including tissue repair. However, the participation of stem cells...Full Text Available

2011-01-01

64

Evidence for Diversity in Transcriptional Profiles of Single Hematopoietic Stem Cells  

UK PubMed Central (United Kingdom)

Hematopoietic stem cells replenish all the cells of the blood throughout the lifetime of an animal. Although thousands of stem cells reside in the bone marrow, only a few contribute to blood production...Full Text Available

2006-09-01

65

Conservation of spermatogonial stem cell self-renewal signaling between mouse and rat  

UK PubMed Central (United Kingdom)

Self-renewal of spermatogonial stem cells (SSCs) is the foundation for maintenance of spermatogenesis throughout life in males and for continuation of a species. The molecular mechanism underlying stem...Full Text Available

2005-10-04

66

C. elegans as a model for stem cell biology  

UK PubMed Central (United Kingdom)

We review the application of C. elegans as a model system to understand key aspects of stem cell biology. The only bona fide stem cells in C. elegans...Full Text Available

2010-05-01

67

High power testing of a 17 GHz photocathode RF gun  

Energy Technology Data Exchange (ETDEWEB)

The authors report experimental results on a high gradient 17 GHz RF photocathode gun. The photocathode RF gun is a novel electron beam source intended to meet the requirements set by future high-energy linear colliders and next generation free electron lasers. A coupled pair of pillbox TM{sub 010}-like resonators is excited by sidewall coupled microwaves at 17 GHz. A picosecond ultraviolet laser pulse illuminates one wall of the structure at the axis of symmetry. Electrons are released by the photoelectric effect and are accelerated by the electric field of the microwaves in the cavity. The high frequency of operation raises the RF breakdown limit allowing strong electric fields to be used. In turn, the intense fields result in rapid acceleration of the electrons to relativistic speeds and reduced space charge induced emittance growth.

1996-12-31

68

Future directions in controlling the LAMPF-PSR Accelerator Complex at Los Alamos National Laboratory  

Energy Technology Data Exchange (ETDEWEB)

Four interrelated projects are underway whose purpose is to migrate the LAMPF-PSR Accelerator Complex control systems to a system with a common set of hardware and software components. Project goals address problems in performance, maintenance and growth potential. Front-end hardware, operator interface hardware and software, computer systems, network systems and data system software are being simultaneously upgraded as part of these efforts. The efforts are being coordinated to provide for a smooth and timely migration to a client-sever model-based data acquisition and control system. An increased use of the distributed intelligence at both the front-end and operator interface is a key element of the projects. 2 refs., 2 figs.

1991-01-01

69

Electron yield enhancement in a laser wakefield accelerator driven by asymmetric laser pulses  

Energy Technology Data Exchange (ETDEWEB)

The effect of asymmetric laser pulses on electron yield from a laser wakefield accelerator has been experimentally studied using > 10{sup 19} cm{sup -3} plasmas and a 10 TW, > 45 fs, Ti:Al{sub 2}O{sub 3} laser. Laser pulse shape was controlled through non-linear chirp with a grating pair compressor. Pulses (76 fs FWHM) with a steep rise and positive chirp were found to significantly enhance the electron yield compared to pulses with a gentle rise and negative chirp. Theory and simulation show that fast rising pulses can generate larger amplitude wakes that seed the growth of the self-modulation instability and that frequency chirp is of minimal importance for the experimental parameters.

2002-08-01

70

Dating Studies of Elephant Tusks Using Accelerator Mass Spectrometry  

Energy Technology Data Exchange (ETDEWEB)

A new method for determining the year of birth, the year of death, and hence, the age at death, of post-bomb and recently deceased elephants has been developed. The technique is based on Accelerator Mass Spectrometry radiocarbon analyses of small-sized samples extracted from along the length of a ge-line of an elephant tusk. The measured radiocarbon concentrations in the samples from a tusk can be compared to the {sup 14}C atmospheric bomb-pulse curve to derive the growth years of the initial and final samples from the tusk. Initial data from the application of this method to two tusks will be presented. Potentially, the method may play a significant role in wildlife management practices of African national parks. Additionally, the method may contribute to the underpinnings of efforts to define new international trade regulations, which could, in effect, decrease poaching and the killing of very young animals.

2002-10-03

71

The advancement of stem cells in radiation medicine  

International Nuclear Information System (INIS)

It may result in acute radiation syndrome after body is exposed to ionizing radiation. The one of long-term effects of irradiation injury is leukemia. The bone marrow cells (BMC) transplantation including stem cells is the only effective therapy for acute radiation syndrome patients. Recently, with the advancement of stem cell research that the stem cells have multipotential and can convert each other, it may supply the new stem source for the irradiation injury patients. At the same time with the further research of radioprotective reagents, the hematopoietic stem cells proliferation after irradiation injury is promoted

2003-02-01

72

Unmasking Stem/Progenitor Cell Properties in Differentiated ...  

Science.gov (United States)

... In addition to changes in BrdU, we also observed transient changes in p63 gene expression in the myoepithelial/stem cell layer. ...

2007-08-01

73

Optical Spectroscopy for Noninvasive Monitoring of Stem Cell Differentiation  

UK PubMed Central (United Kingdom)

There is a requirement for a noninvasive technique to monitor stem cell differentiation. Several candidates based on optical spectroscopy are discussed in this review: Fourier transform infrared (FTIR)...Full Text Available

2010-01-01

74

Continuity and change  

Science.gov (United States)

... with the loosening of Bush-era restrictions on stem cell research, a move that was widely hailed by the ... The first two explore the contentious debate over stem cell research. Using a series of intervie...

75

Electrorheological RayleighTaylor instability at the interface between a porous layer and thin shell with poorly conducting couple stress fluid  

British Library Electronic Table of Contents (United Kingdom)

This paper is concerned with the study of the Electrorheological RayleighTaylor instability (ERTI) at the interface between a densely packed saturated poorly conducting couple stress porous layer accelerated by a lighter poorly conducting couple stress fluid in a thin shell in the presence of a transverse electric field and laser radiation. A simple theory based on fully developed flow approximations is used to derive the dispersion relation for the growth rate of ERTI. The cutoff and the maximum wave numbers and the corresponding maximum frequencies are obtained. It is shown that the effects of couple stress parameter and the electric field reduce the growth rate considerably compared to a non-conducting fluid in the absence of an electric field. These are favorable to control the surface...

2011-01-01

76

Density changes in plutonium observed from accelerated aging using Pu-238 enrichment  

Energy Technology Data Exchange (ETDEWEB)

In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 at.% of {sup 238}Pu is underway using dilatometry at 35, 50, and 65 deg. C and immersion density measurements of materials stored at 50 deg. C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After 25 equivalent years of aging, the dilatometry data shows that the alloys at 35 deg. C have expanded in volume by 0.11-0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-to-vacancy ratio from tested specimens was determined to be around 2.55. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35 deg. C. The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.

2006-09-01

77

Density changes in plutonium observed from accelerated aging using Pu-238 enrichment  

International Nuclear Information System (INIS)

In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 at.% of "2"3"8Pu is underway using dilatometry at 35, 50, and 65 deg. C and immersion density measurements of materials stored at 50 deg. C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After 25 equivalent years of aging, the dilatometry data shows that the alloys at 35 deg. C have expanded in volume by 0.11-0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-to-vacancy ratio from tested specimens was determined to be around 2.55. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35 deg. C. The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.

2006-09-01

78

Density Changes in Plutonium Observed from Accelerated Aging Using Pu-238 Enrichment  

Energy Technology Data Exchange (ETDEWEB)

In support of Stockpile Stewardship activities, accelerated aging tests on a plutonium alloy enriched with 7.3 atomic percentage of {sup 238}Pu is underway using dilatometry at 35, 50, and 65 C and immersion density measurements of material stored at 50 C. Changes in density are expected from radiation damage in the lattice and helium in-growth. After twenty-five equivalent years of aging, the dilatometry data shows that the alloys at 35 C have expanded in volume by 0.11% to 0.12% and have started to exhibit a near linear expansion behavior primarily caused by the helium accumulation. The average He-to-vacancy ratio from tested specimens was determined to be around 2.3. The model for the lattice damage and helium in-growth accurately represents the volume swelling at 35 C. The density converted from the dilatometry corresponds well to the decreasing density trend of reference plutonium alloys as a function of time.

2005-10-19

79

The crystalline-silicon photovoltaic R&D project at NREL and SNL  

Energy Technology Data Exchange (ETDEWEB)

This paper summarizes the U.S. Department of Energy R&D program in crystalline-silicon photovoltaic technology, which is jointly managed by Sandia National Laboratories and National Renewable Energy Laboratory. This program features a balance of basic an d applied R&D, and of university, industry, and national laboratory R&D. The goal of the crystalline-silicon R&D program is to accelerate the commercial growth of crystalline-silicon photovoltaic technology, and four strategic objectives were identified to address this program goal. Technical progress towards meeting these objectives is reviewed.

1996-12-31

80

High-current negative-ion beam transport  

Energy Technology Data Exchange (ETDEWEB)

The requirements for transporting high-current, negative-ion beams are presented with particular emphasis on applications involving negative-hydrogen-ion beams. In addition to the usual matching and steering problems, particular attention must be paid to beam emittance growth in the transport system. Depending on the application, a number of approaches have been developed using both magnetic and electric lenses. I discuss the design considerations for transporting and matching these beams to radiofrequency quadrupole accelerators, and present a survey of the various types of beamlines now used for negative-ion beams.

1993-01-01

81

High-current negative-ion beam transport  

Energy Technology Data Exchange (ETDEWEB)

The requirements for transporting high-current, negative-ion beams are presented with particular emphasis on applications involving negative-hydrogen-ion beams. In addition to the usual matching and steering problems, particular attention must be paid to beam emittance growth in the transport system. Depending on the application, a number of approaches have been developed using both magnetic and electric lenses. I discuss the design considerations for transporting and matching these beams to radio-frequency quadrupole accelerators, and present a survey of the various types of beamlines now used for negative-ion beams.

1992-10-05

82

High-current negative-ion beam transport  

Energy Technology Data Exchange (ETDEWEB)

The requirements for transporting high-current, negative-ion beams are presented with particular emphasis on applications involving negative-hydrogen-ion beams. In addition to the usual matching and steering problems, particular attention must be paid to beam emittance growth in the transport system. Depending on the application, a number of approaches have been developed using both magnetic and electric lenses. I discuss the design considerations for transporting and matching these beams to radiofrequency quadrupole accelerators, and present a survey of the various types of beamlines now used for negative-ion beams.

1993-04-01

83

Simon A. Levin's Passion for Ecology  

Science.gov (United States)

... prominent example today, perhaps, is the issue of stem cell research, but there is a whole list of issues ... ...

85

Effect of Al and Be ions pre-implantation on formation and growth of helium bubbles in SiC/SiC composites  

Energy Technology Data Exchange (ETDEWEB)

The effect of Al and Be ions pre-implantation on microstructural change and, the formation and growth of He bubbles in SiC/SiC composite was investigated. Four kinds of ion implanted specimens were prepared with 100 appm Al, 1000 appm Al, 100 appm Be and 1000 appm Be implanted. No microstructural change was observed in the matrices and fibers of SiC/SiC composites implanted with Al or Be ions up to 1000 appm. The un-implanted and Al or Be pre-implanted SiC/SiC composites were simultaneously irradiated to 10 dpa using triple ion-beams (6.0-MeV Si{sup 2+}, 1.0-MeV He{sup +} and 340-keV H{sup +}) at 1000 deg. C. Helium bubbles were formed in every matrix and fiber irradiated by triple ion-beams. The size of He bubbles in the matrix was increased by implanting Al or Be ions and increased with increasing amount of implanted Al or Be ions. The size of He bubbles in the fiber was slightly increased by implanting Al or Be ions. These results suggest that Al or Be as ...

2007-03-15

86

Effect of Al and Be ions pre-implantation on formation and growth of helium bubbles in SiC/SiC composites  

International Nuclear Information System (INIS)

The effect of Al and Be ions pre-implantation on microstructural change and, the formation and growth of He bubbles in SiC/SiC composite was investigated. Four kinds of ion implanted specimens were prepared with 100 appm Al, 1000 appm Al, 100 appm Be and 1000 appm Be implanted. No microstructural change was observed in the matrices and fibers of SiC/SiC composites implanted with Al or Be ions up to 1000 appm. The un-implanted and Al or Be pre-implanted SiC/SiC composites were simultaneously irradiated to 10 dpa using triple ion-beams (6.0-MeV Si"2"+, 1.0-MeV He"+ and 340-keV H"+) at 1000 deg. C. Helium bubbles were formed in every matrix and fiber irradiated by triple ion-beams. The size of He bubbles in the matrix was increased by implanting Al or Be ions and increased with increasing amount of implanted Al or Be ions. The size of He bubbles in the fiber was slightly increased by implanting Al or Be ions. These results suggest that Al or Be as transmutation ...

2007-03-01

87

Proteomic Profiling of Mesenchymal Stem Cell Responses to Mechanical Strain and TGF-B1  

Energy Technology Data Exchange (ETDEWEB)

Mesenchymal stem cells (MSCs) are a potential source of smooth muscle cells (SMCs) for constructing tissue-engineered vascular grafts. However, the details of how specific combinations of vascular microenvironmental factors regulate MSCs are not well understood. Previous studies have suggested that both mechanical stimulation with uniaxial cyclic strain and chemical stimulation with transforming growth factor {beta}1 (TGF-{beta}1) can induce smooth muscle markers in MSCs. In this study, we investigated the combined effects of uniaxial cyclic strain and TGF-{beta}1 stimulation on MSCs. By using a proteomic analysis, we found differential regulation of several proteins and genes, such as the up-regulation of TGF-{beta}1-induced protein ig-h3 (BGH3) protein levels by TGF-{beta}1 and up-regulation of calponin 3 protein level by cyclic strain. At the gene expression level, BGH3 was induced by TGF-{beta}1, but calponin 3 was not significantly ...

2009-10-12

88

Factoring Potential Accelerator Transmutation of Waste Demonstrations into Accelerator Production of Tritium Design Planning  

CERN Document Server

Factoring Potential Accelerator Transmutation of Waste Demonstrations into Accelerator Production of Tritium Design Planning

1998-01-01

92

Electron acceleration in supernova remnants and diffuse gamma rays above 1 GeV  

DEFF Research Database (Denmark)

The recently observed X-ray synchrotron emission from four supernova remnants (SNRs) has strengthened the evidence that cosmic-ray electrons are accelerated in SNRs. We show that if this is indeed the case, the local electron spectrum will be strongly time-dependent, at least above roughly 30 GeV. The time dependence stems from the Poisson fluctuations in the number of SNRs within a certain volume and within a certain time interval. As far as cosmic-ray electrons are concerned, the Galaxy looks like actively bubbling Swiss cheese rather than a steady, homogeneously filled system. Our finding has important consequences for studies of the Galactic diffuse gamma-ray emission, for which a strong excess over model predictions above 1 GeV has recently been reported. While these models relied on an electron injection spectrum with index 2.4 (chosen to fit the local electron flux up to 1 TeV), we show that an electron injection index of around 2.0 ...

1998-01-01

93

Silver nanoparticles directly formed on natural macroporous matrix and their anti-microbial activities  

Energy Technology Data Exchange (ETDEWEB)

In this study, silver nanoparticles were formed on a natural macroporous matrix, the stem of rice-paper plant, by reducing Ag{sup +} in aqueous solution through in situ processing without using any other stabilizers. The pores of the matrix, with their size of about 100 {mu}m, were thought to act as reaction compartments for the nucleation and growth of silver nanoparticles, and the control of nucleation of silver crystal during the reduction reaction was found to be important to the successful formation of nanosized silver particles onto the matrix. The diameter and amount of resultant silver particles can be controlled by changing the reaction conditions. Under optimized conditions, the content of silver particles in the matrix can reach as high as 1.8 wt% with the particle diameters being kept below 100 nm. The anti-microbial activities in terms of minimum inhibitory concentration (MIC) for the silver nanoparticle composites against ...

2007-02-07

94

Preclinical evidence for the benefits of penile rehabilitation therapy following nerve-sparing radical prostatectomy.  

Science.gov (United States)

Erectile dysfunction following radical prostatectomy remains a frequent problem despite the development of nerve-sparing techniques. This erectile dysfunction is believed to be neurogenic, enhanced by hypoxia-induced structural changes which result in additional veno-occlusive dysfunction. Recently, daily use of intracavernous vasoactive substances and oral use of PDE5-inhibitors have been clinically studied for treatment of postprostatectomy erectile dysfunction. Since these studies showed benefits of "penile rehabilitation therapy," these effects have been studied in a preclinical setting. We reviewed experimental literature on erectile tissue preserving and neuroregenerative treatment strategies, and found that preservation of the erectile tissue by the use of intracavernous nitric oxide donors or vasoactive substances, oral PDE5-inhibitors, and hyperbaric oxygen therapy improved erectile function by antifibrotic effects and preservation of smooth muscle. Furthermore, ...

2008-01-01

95

Workshop on stems and trunks in plant form and function. Final report  

Energy Technology Data Exchange (ETDEWEB)

This document is the final report on the workshop on stems and trunks in plant form and function relating to DOE grant DE-FG06-93ER20128 which took place at Oregon State University in February 1994. The resulting book is organized into four sections and a synthesis: roles of stem architecture in plant performance, roles of stems in transport and storage of water, roles of live stem cells in plant performance, and the roles of stems in preventing or reacting to response to plant injury. The synthesis stemmed from debated and discussion by the authors and a few dozen other workshop participants. The authors cover many stem functions, although the list is not exhaustive, and the focus is on terrestrial woody tree stems, primarily of temperate and boreal zones. More research on trunks, branches and twigs is important for a ...

1995-03-01

96

Molecular marks for epigenetic identification of developmental and cancer stem cells  

British Library Electronic Table of Contents (United Kingdom)

Epigenetic regulations of genes by reversible methylation of DNA (at the carbon-5 of cytosine) and numerous reversible modifications of histones play important roles in normal physiology and development, and epigenetic deregulations are associated with developmental disorders and various disease states, including cancer. Stem cells have the capacity to self-renew indefinitely. Similar to stem cells, some malignant cells have the capacity to divide indefinitely and are referred to as cancer stem cells. In recent times, direct correlation between epigenetic modifications and reprogramming of stem cell and cancer stem cell is emerging. Major discoveries were made with investigations on reprogramming gene products, also known as master regulators of totipotency and inducer of pluoripotency, na...

2011-01-01

97

Life span of multipotential hematopoietic stem cells in vivo  

Energy Technology Data Exchange (ETDEWEB)

The findings reported in this study highlight several important features of the development of hematopoietic stem cells after transplantation into irradiated recipients. First, they demonstrate the existence of a class of primitive multipotential stem cells that can function for a significant portion of the lifetime of a mouse (15 mo). In addition, they clearly show that these primitive stem cells can be infected with recombinant retroviruses and thus would be appropriate targets for gene therapy in somatic tissues. Second, our data indicate that the progeny of some, but not all, of the primitive stem cells have fully expanded into the various hematopoietic lineages by 2 mo after reconstitution. Finally, our analysis of the secondary recipients provides strong evidence suggesting that the primitive stem cell population can actually clonally expand. Our current experiments are aimed ...

1990-05-01

98

Developing defined culture systems for human pluripotent stem cells  

British Library Electronic Table of Contents (United Kingdom)

Human pluripotent stem cells hold promising potential in many therapeutics applications including regenerative medicine and drug discovery. Over the past three decades, embryonic stem cell research has illustrated that embryonic stem cells possess two important and distinct properties: the ability to continuously self-renew and the ability to differentiate into all specialized cell types. In this article, we will discuss the continuing evolution of human pluripotent stem cell culture by examining requirements needed for the maintenance of self-renewal in vitro. We will also elaborate on the future direction of the field toward generating a robust and completely defined culture system, which has brought forth collaborations amongst biologists and engineers. As human pluripotent stem cell re...

2011-01-01

99

First Result of Induction Acceleration in the KEK Proton Synchrotron  

CERN Document Server

First Result of Induction Acceleration in the KEK Proton Synchrotron

2005-01-01

100

A Bragg curve ionization chamber for acceleration mass spectrometry  

CERN Document Server

A Bragg curve ionization chamber for acceleration mass spectrometry

1985-01-01

101

The Future of Induced Pluripotent Stem Cells for Cardiac Therapy and Drug Development.  

Science.gov (United States)

The field of stem cell research was revolutionized with the advent of induced pluripotent stem cells. By reprogramming somatic cells to pluripotent stem cells, most ethical concerns associated with the use of embryonic stem cells are overcome, such that many hopes from the stem cell field now seem a step closer to reality. Several methods and cell sources have been described to create induced pluripotent stem cells and we discuss their characteristics in terms of feasibility and efficiency. From these cells, cardiac progenitors and cardiomyocytes can be derived by several protocols and most recent advances as well as remaining limitations are being discussed. However in the short time period this technology has been around, evidence emerges that induced pluripotent stem cells may be more prone to genetic defects and maintain an epigenetic ...

2011-09-15

102

Design of APhF-IH Linac for a Compact Medical Accelerator  

CERN Document Server

The design of a small injection linac for a compact medical synchrotron is discussed. The linac design is based on interdigital H-type (IH) drift-tube structure with alternative phase focusing (APhF). A high acceleration rate and an absence of magnetic lenses inside drift-tubes reduce the cost and length of APhF-IH linac in comparison with HIMAC linac based on Alvarez structure with magnet quadrupoles inside drift-tubes. To reduce effects of emittance growth, the RFQ structure is used in front of the APhF linac. In such linac layout, the current transmission of a carbon beam can reach up to 90-100%. In this report, the basic parameters of whole linac are presented, while the design of APhF structure is considered in details. Two reference designs of 4 MeV/u 200 MHz APhF linacs with different voltage distributions along the whole tank have been generated and analyzed numerically. For the first design, a constant voltage distribution along the ...

2003-01-01

103

What's the matter with Kansas?Legislative debates over stem cell research in Kansas and Massachusetts  

Science.gov (United States)

... s the matter with Kansas?Legislative debates over stem cell research in Kansas and MassachusettsBonnie StabileSchool of Public Policy, ... examines the contextual factors shaping legislative debates affec...

104

Stem Cell Research (Updated July 26, 2002).  

Science.gov (United States)

Embryonic stem cells have the ability to develop into virtually any cell in the body, and may have the potential to treat medical conditions such as diabetes and Parkinsons disease. On August 9, 2001, President Bush announced that for the first time feder...

2002-01-01

105

Refilling of Embolized Vessels in Young Stems of Laurel. Do We Need a New Paradigm?1  

UK PubMed Central (United Kingdom)

Recovery of hydraulic conductivity after the induction of embolisms was studied in woody stems of laurel (Laurus nobilis). Previous experiments confirming the recovery of hydraulic...Full Text Available

1999-05-01

106

RNA recognition by the embryonic cell fate determinant and germline totipotency factor MEX-3  

UK PubMed Central (United Kingdom)

Totipotent stem cells have the potential to differentiate into every cell type. Renewal of totipotent stem cells in the germline and cellular differentiation during early embryogenesis rely upon posttranscriptional...Full Text Available

2009-12-01

107

Purpose and regulation of stem cells: a systems-biology view from the Caenorhabditis elegans germ line  

UK PubMed Central (United Kingdom)

Stem cells are expected to play a key role in the development and maintenance of organisms, and hold great therapeutic promises. However, a number of questions must be answered to achieve an...Full Text Available

2009-01-01

108

Proteome of human colon cancer stem cells: A comparative analysis  

UK PubMed Central (United Kingdom)

AIM: To isolate and identify the biological characteristics of human colon cancer stem cells (SW1116 cells) and further study their proteome.METHODS: SW1116 cells were isolated and cultured with...Full Text Available

2011-03-14

109

Propagation of human embryonic and induced pluripotent stem cells in an indirect co-culture system  

UK PubMed Central (United Kingdom)

We have developed and validated a microporous poly(ethylene terephthalate) membrane-based indirect co-culture system for human pluripotent stem cell (hPSC) propagation, which allows real-time...Full Text Available

2010-03-05

110

Mesenchymal Stem Cells for Craniofacial Tissue Regeneration: Designing Hydrogel Delivery Vehicles  

UK PubMed Central (United Kingdom)

Craniofacial injuries require a variety of different cell types to repopulate areas of bone, cartilage, tendon, and fat. Mesenchymal stem cells (MSCs) provide a multipotent cell source for tissue...Full Text Available

2009-08-01

111

Long-Lasting Inhibitory Effects of Fetal Liver Mesenchymal Stem Cells on T-Lymphocyte Proliferation  

UK PubMed Central (United Kingdom)

Human bone marrow mesenchymal stem cells (BM-MSC) are multipotent progenitor cells that have transient immunomodulatory properties on Natural Killer (NK) cells, Dendritic Cells (DC), and T cells. This...Full Text Available

112

Identification of a stem cell candidate in the normal human prostate gland  

UK PubMed Central (United Kingdom)

Stem cells of the human prostate gland have not yet been identified utilizing a structural biomarker. We have discovered a new prostatic epithelial cell phenotype-expressing cytokeratin 6a (Ck6a+...Full Text Available

2005-03-01

113

Embryonic anti-aging niche  

UK PubMed Central (United Kingdom)

Although functional organ stem cells persist in the old, tissue damage invariably overwhelms tissue repair, ultimately causing the demise of an organism. The poor performance of stem cells in an aged...Full Text Available

114

CXCL12-Mediated Guidance of Migrating Embryonic Stem Cell-Derived Neural Progenitors Transplanted into the Hippocampus  

UK PubMed Central (United Kingdom)

Stem cell therapies for neurodegenerative disorders require accurate delivery of the transplanted cells to the sites of damage. Numerous studies have established that fluid injections to the hippocampus...Full Text Available

115

CD133 Positive Embryonal Rhabdomyosarcoma Stem-Like Cell Population Is Enriched in Rhabdospheres  

UK PubMed Central (United Kingdom)

Cancer stem cells (CSCs) have been identified in a number of solid tumors, but not yet in rhabdomyosarcoma (RMS), the most frequently occurring soft tissue tumor in childhood. Hence, the aim of this...Full Text Available

116

Abrogation of E-Cadherin-Mediated Cellular Aggregation Allows Proliferation of Pluripotent Mouse Embryonic Stem Cells in Shake Flask Bioreactors  

UK PubMed Central (United Kingdom)

BackgroundA fundamental requirement for the exploitation of embryonic stem (ES) cells in regenerative medicine is the ability to reproducibly derive sufficient numbers of cells of...Full Text Available

117

Studies of the reduction mechanism of selenium dioxide and its impact on the microstructure of manganese electrodeposit  

British Library Electronic Table of Contents (United Kingdom)

The influence of selenium dioxide (SeO2) on the microstructure and electrodeposition of manganese coatings obtained from a sulfate based neutral solution was investigated by material characterization methods and electrochemical techniques. The crystal structure and surface morphology of these coatings were studied by scanning electron microscopy (SEM) and powder X-ray diffraction spectroscopy (XRD), respectively. The SEM and XRD data showed that SeO2 could effectively accelerate phase transformation, and facilitate leveled and fine grain growth. The electrochemical results indicated that SeO2 could inhibit hydrogen evolution reaction and promote manganese deposition. The action of selenium dioxide in manganese deposition was found to be a reduction and adsorption mechanism. The process cou...

2011-01-01

118

Investigations on denting phenomenon in monel tubes  

International Nuclear Information System (INIS)

Denting phenomenon as experienced in PWR steam generators has been investigated in the laboratory of Monel-400 tubes and C-steel baffles combination. Isothermal corrosion tests have been carried out by exposing capsules, containing a crevice between Monel-400 tubes and C-steel plugs, in plausible corrodents at 300"0C. Results indicated that the denting phenomenon is strongly influenced by the chloride content in the solution. In addition, it is a time dependent process. Stress exerted on the tubes by the growth of corrosion product on the outside surface of C-steel plugs are enough to deform the Monel tubes. The results have been discussed on the basis of accelerated corrosion of C-steel by hydrolyzable metal chlorides. (author).

1981-05-01

119

A facile and green preparation of high-quality CdTe semiconductor nanocrystals at room temperature  

Energy Technology Data Exchange (ETDEWEB)

One chemical reagent, hydrazine hydrate, was discovered to accelerate the growth of semiconductor nanocrystals (cadmium telluride) instead of additional energy, which was applied to the synthesis of high-quality CdTe nanocrystals at room temperature and ambient conditions within several hours. Under this mild condition the mercapto stabilizers were not destroyed, and they guaranteed CdTe nanocrystal particle sizes with narrow and uniform distribution over the largest possible range. The CdTe nanocrystals (photoluminescence emission range of 530-660 nm) synthesized in this way had very good spectral properties; for instance, they showed high photoluminescence quantum yield of up to 60%. Furthermore, we have succeeded in detecting the living Borrelia burgdorferi of Lyme disease by its photoluminescence image using CdTe nanocrystals.

2008-06-18

121

The Pan 13th Annual Forum  

Science.gov (United States)

... Exposure Treatment Research Program (NETRP); and a panel of doctors and researchers who will discuss Embryonic Stem Cell Research. ...

2007-11-01

122

Keratoconus: Frequently Asked Questions  

Science.gov (United States)

... a new cornea? As many of you know stem cell research and efforts to develop a replacement cornea have ...

123

Anterior Approach Total Hip Replacement  

Medline Plus

... of the Taperloc Microplasty stem and E-poly antioxidant-infused technology during a hip replacement through the ...

124

Thermal fatigue of stainless steel  

Energy Technology Data Exchange (ETDEWEB)

Two austenitic steels, 316 Stainless Steel and Alloy 800, have been examined under conditions of both isothermal low cycle fatigue (LCF) and thermomechanical fatigue (TMF). The TMF tests were conducted between 649 and 360/sup 0/C with a carefully controlled triangular waveform. The LCF tests were performed at 649/sup 0/C and both kinds of tests were subjected to a strain range of 0.5%. TMF shortened life to 40% for 316 Stainless Steel and to 5% for Alloy 800. The microstructural evolution occurring in both alloys has been examined and we conclude these do not play a role in the life shortening caused by TMF. The TMF does produce asymmetric hysteresis loops with large tensile peak stresses in tests where the maximum temperature corresponded with the peak compressive stress. The influence of TMF on fatigue crack growth rates has been measured and it was found that TMF accelerated crack growth in Alloy 800 and slowed it down ...

1987-12-01

125

Suppression of receptors for prolactin and estrogen in rat liver due to treatment with the growth hormone analogue produced by the tapeworm Spirometra mansonoides.  

Science.gov (United States)

Somatogenic hormones play an important role in regulation of receptors for prolactin (PRL) and estrogen. Plerocercoids of the tapeworm, S. mansonoides produce a factor which mimics some, but not all of the actions reported for GH. Intact female rats were subjected to a constant infusion of plerocercoid growth factor (PGF) via a subcutaneous infection for two weeks to determine if PGF influences receptors for PRL, GH or estradiol. The rate of weight gain in the PGF-treated rats was accelerated in spite of a marked reduction in serum GH. Partially-purified PGF specifically displaced [125I]hGH from rat liver receptors but microsomes prepared from rats treated with PGF specifically bound significantly less [125I]hGH than microsomes from control rats. The reduction in [125I]hGH binding was not due to occupancy or to a change in affinity but to a suppression in receptor concentration. Scatchard analysis of [3H]estradiol binding in rat liver cytosols ...

1986-01-01

126

Early stages during plasma nitriding of pure iron  

Energy Technology Data Exchange (ETDEWEB)

The sequence of nitride formation during the early stages of plasma nitriding of pure iron was studied by optical microscopy, SEM, TEM and x-ray diffraction. Plasma nitriding at {approximately}490 C in a 25 vol.%H{sub 2} + 75 vol.%N{sub 2} mixture starts with the formation of {gamma}{prime}-Fe{sub 4}N after 40s. Once {gamma}{prime} nucleates, it mainly spreads laterally due to diffusion shortcuts in the discontinuous surface nitride layer. Before {gamma}{prime} is continuous on the surface, {epsilon} nucleates on top of it shortly after 40S. Epsilon is then observed to grow, both inwardly and laterally along with {gamma}{prime}. A compact {gamma}{prime}/{epsilon} bilayer forms on the surface at around 100s. The kinetics of nucleation, growth and compactation of the nitrides observed in the present work was significantly more rapid than in any of the nitriding process reported in the literature, including plasma nitriding. The acceleration of ...

1995-12-31

127

A conceptual design study of superconducting proton linac for Neutron Science Project. 1  

Energy Technology Data Exchange (ETDEWEB)

The Neutron Science Project at Japan Atomic Energy Research Institute has been proposed for the research of nuclear transmutation technology and the basic science with a spallation neutron source. The project calls for an 8MW proton linac which accelerates 5.3mA average current cw and pulsed beams up to 1.5GeV. The superconducting (SC) rf-cavity is the main option for the energy part from 100MeV to 1.5GeV because by using the SC structure, less power is consumed in cw operation than by using a normal conducting (NC) structure. A conceptual design study of the superconducting proton linac is reported. The SC linac is composed of 8 {beta} sections. Each section has the identical 5-cell cavities with the surface peak field of 16MV/m. The total number of cavities is 284, and the length of the SC linac is 690m. The lattice design is determined with the equipartitioned condition and the matched envelope equations for the minimum emittance growth. The ...

1998-09-01

128

Variation in the sensitivity of the mouse spermatogonial stem cell population to fission neutron irradiation during the cycle of the seminiferous epithelium  

Energy Technology Data Exchange (ETDEWEB)

Dose-response studies of the radiosensitivity of spermatogonial stem cells in various epithelial stages after irradiation with graded doses of fission neutrons of 1 MeV mean energy were carried out in the Cpb-N mouse. These studies on the stem cell population in stages IX-XI yielded simple exponential lines characterized by an average D0 value of 0.76 +/- 0.02 Gy. In the subsequent epithelial stages XII-III, a significantly lower D0 value of 0.55 +/- 0.02 Gy was found. In contrast to the curves obtained for stem cells in stages IX-III, the curves obtained in stages IV-VIII indicated the presence of a mixture of radioresistant and radiosensitive stem cells. In stage VII, almost no radioresistant stem cells appeared to be present and a D0 value for the radiosensitive stem cells of 0.22 +/- 0.01 Gy was derived. Previously, data were obtained on the size of colonies ...

1986-12-01

129

Establishment and Maintenance of Human Embryonic Stem Cell Lines on Human Feeder Cells Derived from Uterine Endometrium ...  

Science.gov (United States)

... and pathogen transmission. Because the ultimate object of stem cell research is cell-based clinical therapy, hES cells should ... 4%) Supported by grants (SC12021 and SC11012) from Stem Cell Research...

130

Different telomere-length dynamics at the inner cell mass versus established embryonic stem (ES) cells  

UK PubMed Central (United Kingdom)

Murine embryonic stem (ES) cells have unusually long telomeres, much longer than those in embryonic tissues. Here we address whether hyper-long telomeres are a natural property of pluripotent stem cells,...Full Text Available

2011-09-13

131

Clinical and biological assessment of cemented titanium femoral stems: an 11-year experience  

UK PubMed Central (United Kingdom)

This study prospectively assessed the outcome of 134 cemented titanium stems and serum ion levels. The stems were polished (0.1 μm Ra) with circular cross section. At the end point,...Full Text Available

2009-10-01

132

Astrocytes derived from trisomic human embryonic stem cells express markers of astrocytic cancer cells and premalignant stem-like progenitors  

UK PubMed Central (United Kingdom)

BackgroundTrisomic variants of human embryonic stem cells (hESCs) arise spontaneously in culture. Although trisomic hESCs share many properties with diploid hESCs, they also exhibit...Full Text Available

133

Production by surface sputtering and acceleration of heavy negative ions in tandem accelerators  

Energy Technology Data Exchange (ETDEWEB)

The main physical processes allowing negative ion production by surface sputtering for further acceleration in tandem acceleration are briefly reviewed. The sputtering yield and the probability of negative ion ejection are discussed. The properties of negative ion beams for an efficient acceleration in tandem accelerators are also discussed, with an emphasis on space charge problems. The main features and performances of the heavy negative ion injector of the Bucharest tandem accelerator are given.

1992-10-05

134

Crack growth in welded turbine materials at elevated temperatures  

International Nuclear Information System (INIS)

Due to thermal gradients and load changes steam-turbine casings suffer combined creep-fatigue loading. Creep and fatigue portions depend on service conditions. Special interest is focused on the behaviour of creep-fatigue cracks, originated from potential defects due to construction and manufacturing weldments, on residual lifetime assessment. The project deals with the crack-growth behaviour at 530deg C and r.t. of welded and unwelded heat-resistant cast steels: 1% CrMoV-cast (GS-17 CrMoV 5 11, two melts: low and high V-content) and 12% CrMoV-cast (G-X 22 CrMoV 12 1). The crack planes of CT-specimens investigated, taken from manual arc-welded plates, were situated in the heat-affected zone (HAZ). The fatigue, creep and combined creep-fatigue crack-growth behaviour was investigated by means of low-frequency (0.5 and 0.05 Hz) tests, holding-time (20 min) tests and constant load tests up to about 5 000 h. Metallographic investigations show that ...

1989-12-01

135

The effects of high-intensity pulsed electromagnetic field on proliferation and differentiation of neural stem cells of neonatal rats in vitro  

British Library Electronic Table of Contents (United Kingdom)

Summary The effects of high-intensity pulsed electromagnetic stimulation (HIPEMS) on proliferation and differentiation of neonatal rat neural stem cells in vitro were investigated. Neural stem cells derived from neonatal rats were exposed to 0.1 Hz, 0.5-10 Tesla (T) [8 groups of B-I, respectively], 5 stimuli of HIPEMF. The sham exposure controls were correspondingly established. Inverted phase contrast microscope was used to observe the cultured cells, MTT assay to detect the viability of the cells as expressed by absorbance (A) value, and flow cytometry to measure differentiation of neural stem cells. The results showed that A values of neural stem cells in both 3.0 T and 4.0 T groups were significantly higher than the other groups 24 to 168 h post HPEMS, indicating a strong promotion of ...

2009-01-01

136

Silund Nanosecond High-Current Linear Induction Accelerator ...  

Science.gov (United States)

... the high current induction linear accelerator of the nanosecond range, meant to be used as injector in the collective ion accelerator, are presented. ...

1972-07-13

137

Observations on the contributions of environmental restraints and innate stem cell ability to hematopoietic regeneration  

Energy Technology Data Exchange (ETDEWEB)

A competitive repopulation assay utilizing chromosome markers was used to assay the reconstituting potential of hematopoietic populations. The test populations consisted of tibial murine marrow locally irradiated with doses ranging from 1.5 Gy to 8.5 Gy and of marrow generated from either murine splenic or marrow stem cells. The purpose of this assay was to assess the innate proliferative potential and microenvironmental influences on the ability to repopulate. Regardless of origin, spleen repopulating ability consistently agreed with spleen colony-forming unit (CFU-s) content. Doses of radiation from 5 Gy to 8.5 Gy diminished, by a factor of 2, the ability to repopulate marrow despite maintenance of CFU-s levels. Marrow generated from splenic stem cells had one-fifth the repopulating ability of marrow derived from marrow stem cells, even though CFU-s levels were equivalent. The results imply that the splenic environment ...

1988-03-01

138

Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells in irradiated bone marrow cell culture in vitro  

Energy Technology Data Exchange (ETDEWEB)

Effects of cell concentrations on the survival and repopulation of haemopoietic stem cells after irradiation were studied in the long-term culture of mouse bone marrow cells in vitro. No difference was observed in the survival of the stem cells among cultures in which 0 - 10/sup 7/ cells were re-inoculated on the adherent cell colonies in the culture flask. Stem cells showed a significant proliferation within 1 week and the number of the stem cells exceeded the control in 3 weeks after irradiation in the cultures with less than 10/sup 6/ re-inoculated cells per flask. In contrast, there was a considerable delay in the onset of stem cell proliferation after irradiation in the culture with 10/sup 7/ cells per flask. Based on these results, a possibility that a stimulator of stem cell proliferation, released from irradiated stromal cells, is cancelled by an ...

1981-12-01

139

Assessing the risk of ovarian hyperstimulation syndrome in egg donation: implications for human embryonic stem cell research.  

Science.gov (United States)

Stem cell research has important implications for medicine. The source of stem cells influences their therapeutic potential, with stem cells derived from early-stage embryos remaining the most versatile. Somatic cell nuclear transfer (SCNT), a source of embryonic stem cells, allows for understandings about disease development and, more importantly, the ability to yield embryonic stem cell lines that are genetically matched to the somatic cell donor. However, SCNT requires women to donate eggs, which involves injection of ovulation-inducing hormones and egg retrieval through laparoscopy or transvaginal needle aspiration. Risks from this procedure are fiercely debated, most notably risk of ovarian hyperstimulation syndrome (OHSS). This review examines risk of OHSS resulting from oocyte donation. We conclude that risk posed by OHSS in egg donation is not significant enough to warrant ...

2011-09-01

142

Studies of accelerated compact toruses  

Energy Technology Data Exchange (ETDEWEB)

In an earlier publication we considered acceleration of plasma rings (Compact Torus). Several possible accelerator configurations were suggested and the possibility of focusing the accelerated rings was discussed. In this paper we consider one scheme, acceleration of a ring between coaxial electrodes by a B/sub theta/ field as in a coaxial rail-gun. If the electrodes are conical, a ring accelerated towards the apex of the cone undergoes self-similar compression (focusing) during acceleration. Because the allowable acceleration force, F/sub a/ = kappaU/sub m//R where (kappa < 1), increases as R/sup -2/, the accelerating distance for conical electrodes is considerably shortened over that required for coaxial electrodes. In either case, however, since the accelerating flux can expand as the ring ...

1983-01-04

143

Committed T lymphocyte stem cells of rats. Characterization by surface W3/13 antigen and radiosensitivity  

Energy Technology Data Exchange (ETDEWEB)

The existence of stem cells committed to the T lymphoid lineage was deduced from studying how rat T and B stem cells differ in their expression of membrane W3/13 antigen and in their susceptibility in vivo to gamma irradiation. Stem cell activity of rat bone marrow and fetal liver was measured in long-term radiation chimeras using B and T cell alloantigenic surface markers to identify the progeny of donor cells. Monoclonal mouse anti-rat thymocyte antibody W3/13 labeled approximately 40% of fetal liver cells and 60-70% of young rat bone marrow cells (40% brightly, 25% dimly). Bright, dim, and negative cells were separated on a fluorescence-activated cell sorter. All B and T lymphoid stem cells in fetal liver were W3/13 bright, as were B lymphoid stem cells in bone marrow. W3/13 dim bone marrow had over half the T cell repopulating activity of unseparated marrow but gave virtually no ...

1981-01-01

144

A study on the passive film of Alloy 600 and Alloy 690 formed in the high temperature aqueous solution with additives  

Energy Technology Data Exchange (ETDEWEB)

Alloy 690 and Alloy600 are used as a material for the steam generator tubing in the pressurized water reactor(PWR) of nuclear power plants due to its high corrosion resistance. Although those are a highly corrosion resistance material, their stress corrosion cracking(SCC) have been found on occasion, which are deeply related to a surface oxide film on a base material which have occurred on the primary side as well as the secondary side of a tubing. And The SCC is accelerated in the existing Pb which is the impurity of secondary steam generator components. The Oxide on a steel surface in an aqueous solution above 100 .deg. C is composed of a duplex film structure. The inner layer of the oxide is dense and less porous, which is formed by a growth of the oxide layer on the metal surface. The outer layer of the oxide is less adhesive, which is formed by a dissolution and precipitation mechanism. Growth processes of the inner ...

2008-10-15

145

A study on the passive film of Alloy 600 and Alloy 690 formed in the high temperature aqueous solution with additives  

International Nuclear Information System (INIS)

Alloy 690 and Alloy600 are used as a material for the steam generator tubing in the pressurized water reactor(PWR) of nuclear power plants due to its high corrosion resistance. Although those are a highly corrosion resistance material, their stress corrosion cracking(SCC) have been found on occasion, which are deeply related to a surface oxide film on a base material which have occurred on the primary side as well as the secondary side of a tubing. And The SCC is accelerated in the existing Pb which is the impurity of secondary steam generator components. The Oxide on a steel surface in an aqueous solution above 100 .deg. C is composed of a duplex film structure. The inner layer of the oxide is dense and less porous, which is formed by a growth of the oxide layer on the metal surface. The outer layer of the oxide is less adhesive, which is formed by a dissolution and precipitation mechanism. Growth processes of the inner ...

2008-10-01

146

The radiosensitivity of spermatogonial stem cells in C3H/101 F[sub 1] hybrid mice  

Energy Technology Data Exchange (ETDEWEB)

The radiosensitivity of spermatogonial stem cells of C3H/HeHx101/H F[sub 1] hybrid mice was determined by counting undifferentiated spermatogonia at 10 days after X-irradiation. During the spermatogenic cycle, differences in radiosensitivity were found, which were correlated with the proliferative activity of the spermatogonial stem cells. In stage VIII[sub irr], during quiescence, the spermatogonial stem cells were most radiosensitive with a D[sub 0] of 1.4 Gy. In stages XI[sub irr]-V[sub irr], when the cells were proliferatively active, the D[sub 0] was about 2.6 Gy. Based on the D[sub 0] values for sensitive and resistant spermatogonia and on the D[sub 0] for the total population, a ratio of 45:55% of sensitive to resistant spermatogonial stem cells was estimated for cell killing. When the present data were compared with data on translocation induction obtained in mice of the same genotype, a close ...

1993-12-01

147

Stem cell kinetics in spleen and bone marrow after single and fractionated irradiation of infant mice  

Energy Technology Data Exchange (ETDEWEB)

The number and type of stem cells in spleen and bone marrow of mice were determined after exposure to a single dose of 150 R on day 6, to a single dose of 500 R on day 6 or day 9 or to a fractionated dose of 150 R + 350 R on day 6 and 9. The stem cells were assayed on the basis of colony forming units (CFU) in spleen and of incorporation of iododeoxyuridine in spleen and bone marrow of lethally irradiated host mice. During the first month of life, the number of stem cells in non-irradiated mice increases markedly in bone marrow and slightly in spleen. Irradiation causes a long-lasting depression in stem cells, particularly in bone marrow and affecting preferentially erythropoietic precursor cells. Following a dose of only 150 R, the number of CFU in bone marrow is still below control levels 24 days later. An exposure to 500 R fractionated between day 6 and 9 has a markedly greater effect on ...

1980-12-01

148

Poncirin promotes osteoblast differentiation but inhibits adipocyte differentiation in mesenchymal stem cells.  

Science.gov (United States)

Poncirin, flavanone glycoside, isolated from the fruit of Poncirus trifoliata, has anti-bacterial and anti-inflammatory activities. In this study, the effects of poncirin on the differentiation of mesenchymal stem cells were investigated. The C3H10T1/2 mesenchymal stem cells and primary bone marrow mesenchymal stem cells were studied. In the C3H10T1/2 cells, poncirin prevented adipocyte differentiation, as demonstrated by inhibition of cytoplasm lipid droplet accumulation and peroxisome proliferator-activating receptor-? (PPAR-?) and CCAAT-enhancer-binding protein-? (C/EBP-?) mRNA expression. By contrast, poncirin enhanced the expression of the key osteogenic transcription factors, runt-related transcription factor 2 (Runx2) and transcriptional coactivator with PDZ-binding motif (TAZ). Poncirin also enhanced expression of the osteogenic marker genes including alkaline phosphatase (ALP) and osteocalcin (OC). Poncirin ...

2011-05-01

149

Direct sub-nanometer scale electron microscopy analysis of anion incorporation to self-ordered anodic alumina layers  

International Nuclear Information System (INIS)

Research highlights: #-># Morphological and chemical characterization at atomic scale of porous alumina layers anodised in ordered regimes. #-># Characterization based on the use of FEG-SEM, STEM-HAADF, STEM-EELS and STEM-X-EDS. #-># Nanoscale distribution of P-, C- and S-bearing species in the pore wall. - Abstract: Ordered porous alumina layers prepared by two-step anodising in phosphoric, oxalic and sulphuric acids have been characterized at sub-nanometer scale using electron microscopy techniques. FEG-SEM and STEM-HAADF images allowed estimating the pore size, cell wall and pore wall thicknesses of the layers. Nanoanalytical characterization has been performed by STEM-EELS and STEM-X-EDS. Detailed features of the spatial distribution of anions in the pore wall of the films have been obtained. Maximum concentration of P-species occurs, approximately, ...

2010-11-01

150

Cytotoxic effects of WR-2721 on mouse testicular cells  

Energy Technology Data Exchange (ETDEWEB)

WR-2721 (S-2-(3-aminopropylamino)ethylphosphorothioic acid) has been demonstrated to be cytotoxic to stem spermatogonia in the mouse. Five and 10 injections of 300 mg/kg killed sufficient numbers of stem cells to reduce sperm production 56 days after treatment by 16 and 43%, respectively. Single injections of 300 or 400 mg/kg of WR-2721 given 15 min after irradiation produced negligible toxicity to stem cells as measured by counts of repopulated tubules; 600 mg/kg reduced stem cell survival by 47%. Four daily injections of 300 mg/kg given 4, 3, 2, and 1 days prior to irradiation reduced stem cell survival by about 60%. The cytotoxic effects of WR-2721 on testicular stem cells at least partially explains the reduced protection factors observed in the testis with low doses of radiation and during fractionated treatments involving multiple injections of drug.

1984-09-01

151

Search for the active components and studies on the mechanism of the hematopoiesis improvement foods  

Energy Technology Data Exchange (ETDEWEB)

In this experiments, we established long-termed culture methods of bone marrow stromal cells for proliferation and differentiation of stem cells. And we selected some extracts which support maximal proliferation of stromal cells with this method. We conformed the synergic effects of herval mixture extracts for stromal cell growth. The proliferation of stromal cells was increased rather by the addition of mixture extracts than by addition of single strain extract. In the previous and cooperative experiments, we selected complex extracts which increased the number of nonadherent mononuclear cells. Different cytokine expression patterns were observed stromal cells cultured in the presence or absence of mixture extracts which support differentiation of nonadherent cells. Stimulation of macrophage cell line with herval extracts with the treatments of recombinant interferon-{gamma} resulted in increased nitric oxide synthesis in a dose-dependent ...

1999-04-01

152

Large Scale Laser Two-Photon Polymerization Structuring for Fabrication of Artificial Polymeric Scaffolds for Regenerative Medicine  

Science.gov (United States)

We present a femtosecond Laser Two-Photon Polymerization (LTPP) system of large scale three-dimensional structuring for applications in tissue engineering. The direct laser writing system enables fabrication of artificial polymeric scaffolds over a large area (up to cm in lateral size) with sub-micrometer resolution which could find practical applications in biomedicine and surgery. Yb:KGW femtosecond laser oscillator (Pharos, Light Conversion. Co. Ltd.) is used as an irradiation source (75 fs, 515 nm (frequency doubled), 80 MHz). The sample is mounted on wide range linear motor driven stages having 10 nm sample positioning resolution (XY--ALS130-100, Z--ALS130-50, Aerotech, Inc.). These stages guarantee an overall travelling range of 100 mm into X and Y directions and 50 mm in Z direction and support the linear scanning speed up to 300 mm/s. By moving the sample three-dimensionally the position of laser focus in the photopolymer is changed and one is able to write complex 3D ...

2010-11-10

153

Environmental benefits and economic rationale of expanding the Italian natural gas private car fleet  

International Nuclear Information System (INIS)

There are several concerns which bring to consider natural gas as a viable alternative to liquid fuels in transport. First, natural gas allows the curbing of global pollution in this steadily growing industry. Indeed, decoupling greenhouse gas emissions from transport growth has become a major issue in tackling climate change. Second, a more extensive use of natural gas would relieve city air quality, which is presently at levels harmful of human health. Nonetheless, this is just one side of the coin. The other side entails building a refuelling station network, and this carries financial requirements. The financing fraction holds a pivotal role in deciding whether natural gas for automotive purposes is an efficient solution. The final aim of this work is, therefore, to compare the natural gas advantages, stemming from avoided global and local emission, with the economic rationale of engaging in supplementary model network investments. A system ...

2005-01-01

154

Development of functional foods for radiation workers - Search for the active components and studies on the mechanism of the hematopoiesis improvement foods  

Energy Technology Data Exchange (ETDEWEB)

In this experiments, we established long-termed culture methods of bone marrow stromal cells for proliferation and differentiation of stem cells. And we selected some extracts which support maximal proliferation of stromal cells with this method. We conformed the synergic effects of herbal mixture extracts for stromal cell growth. The proliferation of stromal cells was increased rather by the addition of mixture extracts than by addition of single strain extract. In the previous and cooperative experiments, we selected complex extracts (Him-I, Him-II) which increased the number of nonadherent mononuclear cells. Different cytokine expression patterns were observed stromal cells cultured in the presence or absence of mixture extracts which support differentiation of nonadherent cells. Some fractions of Him-I and Him-II increased the proliferation of bone marrow cells irradiated {gamma}-ray(4Gray). Stimulation of macrophage cell line with herval ...

2000-04-01

155

Creation of bony microenvironment with CaP and cell-derived ECM to enhance human bone-marrow MSC behavior and delivery of BMP-2.  

Science.gov (United States)

Extracellular matrix (ECM) comprises a rich meshwork of proteins and proteoglycans, which not only contains biological cues for cell behavior, but is also a reservoir for binding growth factors and controlling their release. Here we aimed to create a suitable bony microenvironment with cell-derived ECM and biodegradable ?-tricalcium phosphate (?-TCP). More specifically, we investigated whether the ECM produced by bone marrow-derived mesenchymal stem cells (hBMSC) on a ?-TCP scaffold can bind bone morphogenetic protein-2 (BMP-2) and control its release in a sustained manner, and further examined the effect of ECM and the BMP-2 released from ECM on cell behaviors. The ECM was obtained through culturing the hBMSC on a ?-TCP porous scaffold and performing decellularization and sterilization. SEM, XPS, FTIR, and immunofluorescent staining results indicated the presence of ECM on the ?-TCP and the amount of ECM increased with the incubation time. ...

2011-05-31

156

Bridging SCADA islands: A solution for the distribution of information and commands among geographically separate control centers  

Energy Technology Data Exchange (ETDEWEB)

This paper describes a gas transmission pipeline company with dissimilar local control and Supervisory Control and Data Acquisition (SCADA) systems that had formed over time, and the solution that was put into place to consolidate those systems. Great Lakes Gas Transmission Company (GLGT) had historically operated the pipeline from four geographically different locations with a combination of various local man-machine interface (MMI) control systems and an aging SCADA system. As new control systems were installed at compressor and meter stations, local and corporate data acquisition needs changed. It became apparent that the existing SCADA system which telemetered a minimal set of control data could no longer support growth requirements. The decision was made to replace the old SCADA system with a new open state-of-the-art architecture. As a result of competitive bidding, the Valmet OASyS (Open Architecture SyStem) was selected and installed at ...

1996-12-31

157

Smart Acquisition EELS  

Energy Technology Data Exchange (ETDEWEB)

Electron energy loss (EEL) spectroscopy and high angle annular dark field (HAADF) imaging in aberration-corrected electron microscopes are powerful techniques to determine the chemical composition and structure of materials at atomic resolution. We have implemented Smart Acquisition, a flexible system of scanning transmission electron microsocpy (STEM) beam position control and EELS collection, on two aberration-corrected dedicated cold field emission gun (FEG) STEMs located at SuperSTEM, Daresbury Laboratory. This allows the collection of EEL spectra from spatially defined areas with a much lower electron dose possible than existing techniques such as spectrum imaging.

2010-07-01

158

discs large in the Drosophila testis  

UK PubMed Central (United Kingdom)

Gamete development requires a coordinated soma-germ line interaction that ensures renewal and differentiation of germline and somatic stem cells. The physical contact between the germline and somatic...Full Text Available

2010-10-01

159

Two subpopulations of stem cells for T cell lineage  

Energy Technology Data Exchange (ETDEWEB)

An assay system for the stem cell that colonizes the thymus and differentiates into T cells was developed, and by using this assay system the existence of two subpopulations of stem cells for T cell lineage was clarified. Part-body-shielded and 900-R-irradiated C57BL/6 (H-2b, Thy-1.2) recipient mice, which do not require the transfer of pluripotent stem cells for their survival, were transferred with cells from B10 X Thy-1.1 (H-2b, Thy-1.1) donor mice. The reconstitution of the recipient's thymus lymphocytes was accomplished by stem cells in the donor cells and those spared in the shielded portion of the recipient that competitively colonize the thymus. Thus, the stem cell activity of donor cells can be evaluated by determining the proportion of donor-type (Thy-1.1+) cells in the recipient's thymus. Bone marrow cells were the most potent source of ...

1985-11-01

160

The lowland forest tree community in Malinau, Kalimantan (Indonesian Borneo): results from a one-hectare plot  

British Library Electronic Table of Contents (United Kingdom)

Background: While Borneo's forests are globally recognised for their diverse vegetation many regions remain uncharacterised. Aims: We examine the tree community in one hectare of lowland (hill) forest near the Malinau River. Methods: We objectively sited a 1-ha plot in primary forest. All stems over 30 cm girth were measured and identified. Results: Stem basal area was typical for Asian rain forests, but the numbers of stems (759) and species (205) were high. The most abundant species were Gluta wallichii, Cleistanthus bakonensis and Lithocarpus cantleyanus, while those contributing most to basal area were Shorea venulosa, Dipterocarpus lowii and Calophyllum lowii. Dipterocarpaceae was the dominant family amongst the largest stems and contributes a third of stand basal area (11.5 m2). Thir...

2010-01-01

162

Stem cell transplantation for neuroblastoma  

UK PubMed Central (United Kingdom)

High-risk neuroblastoma is a childhood malignancy with a poor prognosis. Gradual improvements in survival have correlated with therapeutic intensity, and the ability to harvest, process and...Full Text Available

2008-01-01

163

Stem Cells, Nitrogen-Rich Plasma-Polymerized Culture Surfaces, and Type X Collagen Suppression  

British Library Electronic Table of Contents (United Kingdom)

Mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into chondrocytes, osteoblasts, myocytes, adipocytes, and a variety of other cell types. Several studies have been directed toward using MSCs from patients with osteoarthritis (OA) for cartilage repair, not only because these are the ones that will require a source of autologous stem cells if biological repair of cartilage lesions is to be a therapeutic option, but also to further an understanding of stem cell differentiation. Previous studies have shown that a major drawback of current cartilage and intervertebral disc tissue repair is that human MSCs from OA patients express type X collagen (COL X). COL X, a marker of late-stage chondrocyte hypertrophy, is implicated in endochondral ossification. However, those st...

2011-01-01

164

Role of the 5HT3 Receptor in Alcohol Drinking and ...  

Science.gov (United States)

... Proc Natl Acad Sci USA 97:11032-7 27. Duman RS 2002 Genetics of childhood disorders: XXXIX. Stem cell research, part 3: ...

2005-09-01

165

Patterns of proliferation and differentiation of irradiated haemopoietic stem cells cultured on normal 'stromal' cell colonies in vitro  

Energy Technology Data Exchange (ETDEWEB)

Experiments were designed to elucidate whether or not the irradiated bone marrow cells receive any stimulation for the self-replication and differentiation from normal 'stromal' cell colonies in the bone marrow cell culture in vitro. When irradiated or unirradiated bone marrow cells were overlaid on the normal adherent cell colonies, the proliferation of haemopoietic stem cells was supported, the degree of the stimulation depending on the starting cellular concentration. There was, however, no significant changes in the concentration of either CFUs or CFUc regardless of the dose of irradiation on the bone marrow cells overlaid. This was a great contrast to the dose-dependent decrease of CFUs or CFUc within the culture in which both the stem cells and stromal cells were simultaneously irradiated. These results suggest that the balance of self-replication and differentiation of the haemopoietic stem cells is ...

1981-09-01

166

Neural Tissues from the Implanted Stem Cells  

International Science & Technology Center (ISTC)

Morphological, Electrophysiological and Behavioral Investigations of the Nervous Tissue Developed from the Embryonic Matrix Zone Cells of the Dorsolateral Walls of Lateral Ventricles, Implanted into the Lesioned Regions of the Adult Rat's Brain

167

Land Cover Classification Comparison with Different Resolution ...  

Science.gov (United States)

Dec 9, 2005 ... Classification of high resolution imagery is not as straightforward as more ... The challenges of classifying high resolution imagery stems ...

169

Information Technology Experiences for Students and Teachers (ITEST)  

Science.gov (United States)

... for the development of IT classroom materials for students or teachers, or for professional ... STEM education. Innovative instructional materials and student assessments, as well as new models ...

170

HOW IS THE ETHICS OF STEM CELL RESEARCH DIFFERENT FROM THE ETHICS OF ABORTION?:  

British Library Electronic Table of Contents (United Kingdom)

Abstract: It seems that if abortion is permissible, then stem cell research must be as well: it involves the death of a less significant thing (an embryo rather than a fetus) for a greater good (lives saved rather than nine months of physical imposition avoided). However, I argue in this essay that this natural thought is mistaken. In particular, on the assumption that embryos and fetuses have the full moral status of persons, abortion is permissible but one form of stem cell research is not-the practice of creating embryos and then destroying them to extract cell material. Furthermore, I argue that the same is true on the assumption that embryos and fetuses have at least some moral status. I conclude that this form of stem cell research is permissible only if the embryos in question lack ...

2007-01-01

172

Circulating Skeletal Stem Cells  

UK PubMed Central (United Kingdom)

We report the isolation of adherent, clonogenic, fibroblast-like cells with osteogenic and adipogenic potential from the blood of four mammalian species. These cells phenotypically resemble but are...Full Text Available

2001-05-28

173

Bioethics and the Stem Cell Research Debate  

Science.gov (United States)

Bioethics--the study of ethical issues in science and medicine--has grown to become a significant academic and service-oriented discipline with its own research centers, conferences, journals, and degree programs. As these issues have moved to the center of public debate, the law has assumed an increasingly important place in the discipline of bioethics. Today, embryonic stem cell research stands out as a critically important issue about which the U.S. has neither ethical consensus nor clear, comprehensive regulation. The ethical debate centers on the fact that stem cell research involves the destruction of very early human embryos. This article provides a brief scientific background followed by a discussion of key ethical and legal/regulatory issues that surround embryonic stem cell research.

2005-12-01

174

Activation of stem cells in hepatic diseases  

UK PubMed Central (United Kingdom)

The liver has enormous regenerative capacity. Following acute liver injury, hepatocyte division regenerates the parenchyma but, if this capacity is overwhelmed during massive or chronic liver...Full Text Available

2008-01-01

175

A stem cell niche dominance theorem  

UK PubMed Central (United Kingdom)

BackgroundMultilevelness is a defining characteristic of complex systems. For example, in the intestinal tissue the epithelial lining is organized into crypts that are maintained...Full Text Available

176

A New Stem Taper Function for Short-rotation poplar  

Energy Technology Data Exchange (ETDEWEB)

A new stem taper function was established for individual trees of two poplar hybrid clones grown on a short-rotation coppice. The model could be easily fitted and required three parameters to be estimated. It can be used to estimate both diameter at a given height and height for a given top diameter. Two of the three parameters controlled the conical and the neiloid parts of the stem. Significant differences in these parameters were observed between the two clones even if no differences were observed for diameter at breast height or total height of the stem. The model could not be integrated to calculate volumes (total volume, merchantable volume), which were estimated by numerical integration. However, use of this new model allows the optimal length of billets to be determined and thus maximizes the merchantable biomass of poplar in short-rotation coppice by minimizing the biomass of residues.

2003-07-01

177

The dependence of radiation hardening and embrittlement on irradiation temperature  

International Nuclear Information System (INIS)

Assessments of the hardening and embrittlement of pressure vessel steels and welds as a function of neutron dose use trend curves derived from surveillance programs and accelerated irradiation data. A temperature dependent factor is incorporated for assessing vessel locations operating at different temperatures. As hardening and embrittlement arise from the sum of matrix damage and copper impurity precipitation, the influence of irradiation temperature on each process needs to be established. For irradiations performed below #approx# 300 C recent data shows that the dose-dependent growth of copper precipitates ceases at a mean diameter of about 2 nm that also corresponds to peak hardening and embrittlement by copper. For doses beyond this peak copper dose the property-dependence on irradiation temperature can be identified with that of matrix damage alone. An analysis of several experiments on plate steels, performed at differing irradiation ...

1994-06-20

178

Proceedings: Water treeing and aging  

Energy Technology Data Exchange (ETDEWEB)

This report presents the record of the workshop Water Treeing and Aging.'' The workshop was held in Phoenix, Arizona on December 9--11, 1990 and was sponsored by the Distribution Program of the Electrical Systems Division of the Electric Power Research Institute (EPRI). Attendance at the workshop was by invitation only. Twenty two attendees from seven countries, from universities, research organizations, electric utilities and polymeric materials suppliers took part in this workshop. The workshop was designed to assess progress in the understanding of water treeing phenomena and polymeric cable insulation aging since the last meeting of a similar forum of experts, which was organized by the Office of Exploratory Research of EPRI in December 1985. The objective of the present workshop was to assess progress and to provide direction for further studies in this field. The discussions covered a wide range of subjects including water tree structure, initiation, ...

1991-10-01

179

Parametric Resonance Ionization Cooling and Reverse Emittance Exchange for Muon Collider  

Energy Technology Data Exchange (ETDEWEB)

Two methods to cool muon beams deeply below the limit conventionally established for the ionization cooling are proposed. In Phase Ionization Cooling (PIC), the beam is focused at wedge absorber plates each half of particle oscillation period by imposing a weak parametric resonance along the beam path. The resonance growth of particle amplitude is surmounted by the ionization cooling. At optimum, such arrangement results in reduction of each of two transverse emittances by an order of value in addition to the preceding 6D ionization cooling. Next, resonance focusing and transverse cooling can be continued in the regime of a fast Reverse Emittance Exchange (REMEX). Here, the sign of the absorber wedge is opposite to PIC while the dispersion increased. REMEX to be accompanied by the bunch lengthening and acceleration in order to maintain the relative energy spread at an appropriate level. The limitations due to energy straggling in absorber will ...

2005-09-18

180

Overexpression of a maize dehydrin gene, ZmDHN2b, in tobacco enhances tolerance to low temperature  

British Library Electronic Table of Contents (United Kingdom)

Dehydrins, a subfamily of group 2 LEA proteins, are intrinsically unstructured plant proteins that accumulate in the late stages of seed development and in vegetative tissues subjected to water deficit, salinity, low temperature, or abscisic acid treatment. In this study, we isolated and characterized ZmDHN2b, a maize dehydrin gene. The genomic organization of the ZmDHN2b gene and its expression in maize seedlings were analyzed. To investigate the function of ZmDHN2b, we generated transgenic tobacco plants constitutively overexpressing ZmDHN2b. Ectopic expression of ZmDHN2b in tobacco accelerated seed germination and seedling growth at 15?C. Furthermore, ZmDHN2b-overexpressing lines had lower levels of cold-induced malondialdehyde and less electrolyte leakage than wild-type tobacco at 4?C....

2011-01-01

181

Long-term effects of prenatal x-ray of human females: reproductive experience  

Energy Technology Data Exchange (ETDEWEB)

A cohort of singleton black human females exposed to diagnostic x-ray in utero and controls matched by parity, hospital of birth and birthdate have been followed to ages 25 to 30 years in Baltimore, Maryland. The search for possible effects of prenatal irradiation has focused on health, growth, development, and reproductive experience of exposed and control women. This paper reports findings related to reproductive experience. From an original data set of 1458 matched exposed-control pairs of women, questionnaire responses were received from 1109 exposed and 1124 control women including 852 each from pairs in which both the exposed and control woman responded. After careful search for alternative explanations of the findings, the authors concluded that females exposed in utero to low doses of x-ray (probably 1 to 5 rads) had significant increases in their rates of early onset of menses, births at age 15 years or less, numbers of living children, stillbirths, and ...

1981-09-01

182

Higher Education in East Asia and Singapore: Rise of the Confucian Model  

Science.gov (United States)

The paper reviews Asia-Pacific higher education and university research, focusing principally on the "Confucian" education nations Japan, Korea, China, Hong Kong China, Taiwan, Singapore and Vietnam. Except for Vietnam, these systems exhibit a special developmental dynamism--still playing out everywhere except Japan--and have created a distinctive model of higher education more effective in some respects than systems in North America, the English-speaking world and Europe where the modern university was incubated. The Confucian Model rests on four interdependent elements: (1) strong nation-state shaping of structures, funding and priorities; (2) a tendency to universal tertiary participation, partly financed by growing levels of household funding of tuition, sustained by a private duty, grounded in Confucian values, to invest in education; (3) "one chance" national examinations that mediate social competition and university hierarchy and focus family commitments to education; (4) ...

2011-05-01

183

Effect of boron doping in the carbon support on platinum nanoparticles and carbon corrosion  

Energy Technology Data Exchange (ETDEWEB)

Carbon supported catalysts can lose their activity over a period of time due to the sintering of the nanometer-sized catalyst particles. The sintering of metal clusters on carbon supports can occur due to the weak interaction between the metal and the support and also due to the corrosion of carbon, especially in fuel cell electrocatalysts. The sintering may be reduced by increasing the interaction between the metal and the support and also by increasing the corrosion resistance of carbon supports. In an effort to mitigate the growth of the nanoparticles, carbon-substituted boron defects were introduced in the carbon lattice. The interaction between the Pt nanoparticles on the pure and boron-doped carbon supports was examined using X-ray photoelectron spectroscopy (XPS). The results indicate that the interaction between the Pt nanoparticles and the boron-doped carbon support was slightly stronger than the interaction between the Pt nanoparticles and the pure carbon ...

2009-07-15

184

Composition determination of sputter-deposited HgS films by electron microprobe analysis  

Energy Technology Data Exchange (ETDEWEB)

The composition of sputter-deposited HgS films was determined by electron microprobe analysis. From the relative x-ray intensity as a function of film thickness, the depth of the ionizations that produce SK sub(..cap alpha..) and HgM sub(..cap alpha..) was found to be approximately 0.65 ..mu..m at an accelerating voltage of 15 kV. This value agreed well with a value calculated from Castaings' empirical law after absorption correction. The determination of film composition was limited to sufficiently thicker films than this critical value, usually 1 - 2 ..mu..m thick. The relation between the conposition of bulk standard determined by chemical analysis and the x-ray intensity ratio was used for the correction of film composition. The results showed that the crystal structure of HgS films was independent of the composition, i.e., the growth of metastable ..beta..-HgS films was not caused by the nonstoichiometry, and that the composition ...

1982-01-01

185

Composition determination of sputter-deposited HgS films by electron microprobe analysis  

International Nuclear Information System (INIS)

The composition of sputter-deposited HgS films was determined by electron microprobe analysis. From the relative x-ray intensity as a function of film thickness, the depth of the ionizations that produce SK sub(#alpha#) and HgM sub(#alpha#) was found to be approximately 0.65 #mu#m at an accelerating voltage of 15 kV. This value agreed well with a value calculated from Castaings' empirical law after absorption correction. The determination of film composition was limited to sufficiently thicker films than this critical value, usually 1 - 2 #mu#m thick. The relation between the conposition of bulk standard determined by chemical analysis and the x-ray intensity ratio was used for the correction of film composition. The results showed that the crystal structure of HgS films was independent of the composition, i.e., the growth of metastable #betta#-HgS films was not caused by the nonstoichiometry, and that the composition of #alpha#-HgS films was ...

1982-01-01

186

Changes in aerobic digester performance with the use of methanol for biological nutrient removal in a full-scale sequencing batch reactor  

Energy Technology Data Exchange (ETDEWEB)

Increasingly, governments enact more stringent regulations governing nitrogen and phosphorus in the discharge effluent of wastewater treatment plants. Scientists know that nitrogen and phosphorus accelerates the eutrophication of lakes and reservoirs and stimulates algal growth. Ammonia has proven to be toxic to aquatic life forms, including fish. Engineers favour Biological Nutrient Removal (BNR) over chemical addition to wastewater treatment. Sequencing Batch Reactors (SBRs), a type of bioreactor requiring less land, provide the anaerobic, anoxic, and aerobic zones necessary for BNR. Methanol was used as an effective external source of carbon for denitrification but lacked research. The authors remedied this situation and some of the results were available. They indicated that the addition of methanol in the SBR increased solids production in the SBR, leading to increased sludge wasting to the aerobic digester. All aspects of the sludge ...

2000-07-01

187

Aging of Pentaerythritol Tetranitrate (PETN)  

Science.gov (United States)

Pentaerythritol tetranitrate (PETN) is a relatively sensitive explosive used in many electroexplosive devices as well as in medicine. Of primary interest to LLNL is its use in items such as exploding bridgewire (EBW) detonators and exploding bridge foil initiators (EFI). In these devices the crystalline powder is pressed into a granular, low-density compact that can be initiated by an exploding wire or foil. The long-term stability of this pressed compact is of interest to weapon stockpile lifetime prediction studies. Key points about potential aging mechanisms can be summarized as follows: (1) There are a number of factors that can contribute to PETN instability. These include particle size, polymorphic phase transitions, crystal structure, impurities, moisture, occlusions, chemical incompatibility and biological (microorganism) action. of these factors the most important for long-term aging of high surface area powders used in detonators appears to be that of particle size ...

2009-04-22

188

Thermal convection loop study of corrosion of alloy 800 in molten NaNO/sub 3/-KNO/sub 3/  

Energy Technology Data Exchange (ETDEWEB)

Maximum metal loss rate of Alloy 800 coupons was about 0.5 mil/year and occurred at the maximum temperature of 600/sup 0/C. Significantly greater oxide penetration into the alloy occurred in unabraded as-received tubing. Since the corrosion rate of unabraded tubing was less temperature sensitive than polished coupons, and attained a maximum value at temperatures in the range of 550 to 565/sup 0/C, a value of 1 mil/year should be used as the corrosion rate for design purposes. Because daily thermal cycling is inherent in solar central receiver operation, oxidation and chromium depletion rates can be expected to increase if surface oxide layers spall. The oxide layers formed on Alloy 800 appeared to be adherent, and adherence will benefit further from growth-derived compressive stresses in oxide layers on the salt-exposed inner diameter of receiver tubes. Since the lower duty factor in diurnal solar service may offset the accelerated metal loss ...

1983-01-01

189

Construction, testing of the 1 MW, 130-260 GHz Fusion-FEM  

Energy Technology Data Exchange (ETDEWEB)

During the previous 9 months the major part of the Fusion-FEM has been constructed. The 2 MV Insulated Core Transformer, the electron gun, the accelerator, the focusing lenses and the undulator have been tested on-site. In the present - temporary - set-up, the electron beam line consists of a 12 A, 80 keV thermionic electron gun, a 2 MeV dc accelerator, beam transport optics, the undulator and a collector. The gun is mounted in the high voltage terminal, which is now at -2 MV, and the undulator and mm-wave system am at ground potential outside the SF{sub 6}-filled pressure tank. This so-called inverse set-up allows easy access to the larger part of the beam line, the undulator and the mm-wave system, which is important in the conditioning phase. The decelerator and depressed collector am not yet installed. The design of the electron beam line has been optimised using the GPS particle-tracking code and the TOSCA code. The TOSCA code is used for ...

1995-12-31

190

Acceleration of the development of benzopyrene-induced skin cancer in mice by microwave radiation  

Energy Technology Data Exchange (ETDEWEB)

In the present study Balb/c mice were exposed to 3,4-benzopyrene, painted on the skin every 2nd day for a total of 6 months, and simultaneously irradiated with athermal (5 mW/cm/sup 2/) or subthermal (15 mW/cm/sup 2/) doses of 2,450 MHz microwaves. The other group of animals was preirradiated with microwaves at 10 mW/cm/sup 2/ power level for 1, 2, or 3 months and then treated with benzopyrene, as above. Control mice were exposed for 6 months to benzopyrene, resulting in the development of baso- or spinocellular skin carcinoma within approximately 9 months, and sham-irradiated with microwaves. The growth of the tumour was assessed according to a self-designed 7-range macroscopic scale, supported by microscopical examinations of skin sections. All protocols of microwave irradiations resulted in a significant acceleration of the development of benzopyrene-induced skin cancer and in shortening of life span of the tumour-bearing hosts. This effect ...

1982-12-01

191

Water-level variations and their effects on tree growth and mortality and on the biogeochemical system at the phytoremediation demonstration site in Fort Worth, Texas, 1996-2003  

Science.gov (United States)

In 1996, a field-scale phytoremediation demonstration project was initiated and managed by the U.S. Air Force at a site in western Fort Worth, Texas, using a plantation of 1-year-old stems harvested from branches of eastern cottonwoods during the dormant season (whips) and a plantation of 1-year-old eastern cottonwood seedlings (calipers). The primary objective of the demonstration project was to determine the effectiveness of eastern cottonwoods at reducing the mass of dissolved trichloroethene transported within an alluvial aquifer. The U.S. Geological Survey conducted a study, in cooperation with the U.S. Air Force, to determine water-level variations and their effects on tree growth and mortality and on the biogeochemical system at the phytoremediation site. As part of the study, water-level and water-quality data were collected throughout the duration of the project. This report presents water-level variations at periodic sampling ...

2004-01-01

192

Telomerase-immortalized non-malignant human prostate epithelial cells retain the properties of multipotent stem cells  

International Nuclear Information System (INIS)

Understanding prostate stem cells may provide insight into the origin of prostate cancer. Primary cells have been cultured from human prostate tissue but they usually survive only 15-20 population doublings before undergoing senescence. We report here that RC-170N/h/clone 7 cells, a clonal cell line from hTERT-immortalized primary non-malignant tissue-derived human prostate epithelial cell line (RC170N/h), retain multipotent stem cell properties. The RC-170N/h/clone 7 cells expressed a human embryonic stem cell marker, Oct-4, and potential prostate epithelial stem cell markers, CD133, integrin #alpha#2#beta#1"h"i and CD44. The RC-170N/h/clone 7 cells proliferated in KGM and Dulbecco's Modified Eagle Medium with 10% fetal bovine serum and 5 #mu#g/ml insulin (DMEM + 10% FBS + Ins.) medium, and differentiated into epithelial stem cells that expressed epithelial cell markers, including ...

2008-01-01

193

Human breast cancer cell lines contain stem-like cells that self-renew, give rise to phenotypically diverse progeny and survive chemotherapy  

UK PubMed Central (United Kingdom)

IntroductionThe phenotypic and functional differences between cells that initiate human breast tumors (cancer stem cells) and those that comprise the tumor bulk are difficult to...Full Text Available

2008-01-01

194

Human blood and marrow side population stem cell and Stro-1 positive bone marrow stromal cell numbers decline with age, with an increase in quality of surviving stem cells: Correlation with cytokines  

UK PubMed Central (United Kingdom)

Hematological deficiencies increase with aging leading to anemias, reduced hematopoietic stress responses and myelodysplasias. This study tested the hypothesis that side population hematopoietic...Full Text Available

2010-01-01

195

Ethical Issues in Human Stem Cell Research. Executive Summary, Volume 1: Report and Recommendations of the National Bioethics Advisory Commision, Volume 2: Commissioned Papers, and Volume 3: Religious Perspectives.  

Science.gov (United States)

In November 1998, President Clinton charged the National Bioethics Advisory Commission with the task of conducting a thorough review of the issues associated with human stem cell research, balancing all ethical and medical considerations. The President's ...

2000-01-01

196

Distribution of Indole-3-Acetic Acid and the Occurrence of Its Alkali-Labile Conjugates in the Extraxylary Region of Pinus sylvestris Stems 1  

UK PubMed Central (United Kingdom)

Free and conjugated indole-3-acetic acid (IAA) were measured by quantitative gas chromatography-selected ion monitoringmass spectrometry in the extraxylary region of the stem of large Pinus...Full Text Available

1990-08-01

197

Development of a machine combination for harvesting of small wood and first thinnings; Yhdistelmaekoneen kehittaeminen pienpuun korjuuseen sekae ensiharvennukseen  

Energy Technology Data Exchange (ETDEWEB)

The objective of the research was to develop a machine combination for harvesting of small wood, which carries out both the harvesting and forest haulage. The development was started in September 1995. The first prototype of the machine is ready. A Lokomo 910 forest tractor was acquired for the tests. The prototype has been mounted on the tractor, and the tests have been started in the beginning of March 1996. The reconstruction of the device will be made after the tests, as well as the description of different working praxis. Time consumption study and the analysis of it will be made after the equipment tests. The device consists of a grapple equipped with a guillotine cutting device mounted on the tractor. The actual felling is made stem by stem in the test phase. The stem can be forwarded directly into the load or it can be left aside, and new stems can be brought beside it and then all the ...

1996-12-31

198

Some thoughts on stem cells and carcinogenesis. The thyroid gland  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this review is to consider the hypothesis that cancer frequently originates from stem cells. Using the spleen transplantation assay where stem cells were transplanted in the spleen of mice lethally irradiated by ionizing radiation, the author undertook a study aimed at defining the risk of radiogenic cancer per susceptible cells with use of rat radiogenic mammary and thyroid cancers because of the high incidences of these cancers in a-bomb survivors. Measured were the number of cancer-susceptible cells initially present in the tissue, the number of such cells that survived at a given dose and the number of cancers that developed per surviving cell. Thyroid cell differentiation and proliferation in rats transplanted with thyroid cells were enhanced by thyroidectomy and low iodine diet. Further, the relationship between the low LET radiation dose and thyroid clonogen survival was also investigated. Data showed that ...

2000-07-01

199

STEM nanodiffraction technique for structural analysis of CoPt nanoparticles  

Energy Technology Data Exchange (ETDEWEB)

Studying the structure of nanoparticles as a function of their size requires a correlation between the image and the diffraction pattern of single nanoparticles. Nanobeam diffraction technique is generally used but requires long and tedious TEM investigations, particularly when nanoparticles are randomly oriented on an amorphous substrate. We bring a new development to this structural study by controlling the nanoprobe of the Bright and Dark Field STEM (BF/DF STEM) modes of the TEM. The particularity of our experiment is to make the STEM nanoprobe parallel (probe size 1 nm and convergence angle <1 mrad) using a fine tuning of the focal lengths of the microscope illumination lenses. The accurate control of the beam position offered by this technique allowed us to obtain diffraction patterns of many single nanoparticles selected in the digital STEM image. By means of this technique, we demonstrate ...

2008-06-15

200

STEM nanodiffraction technique for structural analysis of CoPt nanoparticles  

International Nuclear Information System (INIS)

Studying the structure of nanoparticles as a function of their size requires a correlation between the image and the diffraction pattern of single nanoparticles. Nanobeam diffraction technique is generally used but requires long and tedious TEM investigations, particularly when nanoparticles are randomly oriented on an amorphous substrate. We bring a new development to this structural study by controlling the nanoprobe of the Bright and Dark Field STEM (BF/DF STEM) modes of the TEM. The particularity of our experiment is to make the STEM nanoprobe parallel (probe size 1 nm and convergence angle <1 mrad) using a fine tuning of the focal lengths of the microscope illumination lenses. The accurate control of the beam position offered by this technique allowed us to obtain diffraction patterns of many single nanoparticles selected in the digital STEM image. By means of this technique, we demonstrate size ...

2008-06-01

201

Role of limited cell replicative capacity in pathological age change. A review  

Energy Technology Data Exchange (ETDEWEB)

Physiological functions are carried out by differentiated cells, with finite lifespans, which age and need to be replaced. In young individuals, tissue functions are sustained at optimal levels because cellular dysfunction and cell loss are balanced by the emergence of newly differentiated cells as stem cells and their partially differentiated descendants replicate. However, with the passage of time the mitotic rates of these cells diminish. Eventually, replications occur too infrequently to offset the loss. It is at this point that the tissue begins to show structural changes and declining function which, as they become pervasive, are identified as ageing. In this paper the theory is set forth that: (1) Diminishing mitotic activity in older tissues results from limited stem cell replicative capacity. (2) All stem cells, regardless of tissue, exhibit similar replicative patterns over time, progressing from the actively ...

1982-01-01

202

Concise review: expanding roles for hematopoietic cellular therapy and the blood transfusion services.  

Science.gov (United States)

Hematopoietic stem cells (HSCs) have remained at the forefront of stem cell research for the past 50 years, since the therapeutic potential of bone marrow transplantation was realized. Uniquely, among stem and progenitor cells, research progress has been made in parallel between the laboratory benchtop and hospital bedside during this period. Integral to this work has been the role of the transfusion medicine services in the collection, storage, and processing of HSCs. The next decade promises to bring further developments: with new fields of cellular therapies, stem cell vaccination, and stem cell drug testing opening up. This article summarizes exciting areas of research concerning the behavior and potential clinical applications of HSCs. For the purposes of clarity, we describe in turn the trafficking and transfer of HSCs; ex vivo expansion of HSC units from different sources; ...

2011-09-01

203

Optimization of shielding for a 60 MeV alpha particle accelerator  

International Nuclear Information System (INIS)

Optimization of radiation shielding for a medium energy accelerator with 60 MeV alpha ions is carried out using the cost-benefit approach. Cost optimum shield thicknesses are estimated for different operating conditions of the accelerator. (author). 5 refs, 1 tab.

1988-04-18

204

Accelerated hyperfractionation (AHF) compared to conventional fractionation (CF) in the postoperative radiotherapy of locally advanced head and neck cancer: influence of proliferation  

UK PubMed Central (United Kingdom)

Based on the assumption that an accelerated proliferation process prevails in tumour cell residues after surgery, the possibility that treatment acceleration would offer a therapeutic advantage in postoperative...Full Text Available

2002-02-12

205

A General Model of the Resistive Wall Instability in Linear Accelerators  

Energy Technology Data Exchange (ETDEWEB)

A general model for wakefield-generated instabilities in linear accelerators, originally developed for cumulative beam breakup [1], is applied to the resistive wall instability. The general solution for various bunch charge distributions and application to various accelerator configurations are presented.

2007-01-08

206

Research and Service Experience with Environmentally-Assisted Cracking in Carbon and Low-Alloy Steels in High-Temperature Water  

Energy Technology Data Exchange (ETDEWEB)

The most relevant aspects of research and service experience with environmentally-assisted cracking (EAC) of carbon (C) and low-alloy steels (LAS) in high-temperature (HT) water are reviewed, with special emphasis on the primary pressure boundary components of boiling water reactors (BWRs). The main factors controlling the susceptibility to EAC under light water reactor (LWR) conditions are discussed with respect to crack initiation and crack growth. The adequacy and conservatism of the current BWRVIP-60 stress corrosion cracking (SCC) disposition lines (DLs), ASME III fatigue design curves, and ASME XI reference fatigue crack growth curves, as well as of the GE EAC crack growth model are evaluated in the context of recent research results. The operating experience is summarized and compared to the experimental/mechanistic background knowledge. Finally, open questions and possible topics for further research are identified. ...

2005-11-15

207

Modeling pitting corrosion damage of high-level radioactive-waste containers, with emphasis on the stochastic approach  

Energy Technology Data Exchange (ETDEWEB)

Recent efforts to identify methods of modeling pitting corrosion damage of high-level radioactive-waste containers are described. The need to develop models that can provide information useful to higher level system performance assessment models is emphasized, and examples of how this could be accomplished are described. Work to date has focused upon physically-based phenomenological stochastic models of pit initiation and growth. These models may provide a way to distill information from mechanistic theories in a way that provides the necessary information to the less detailed performance assessment models. Monte Carlo implementations of the stochastic theory have resulted in simulations that are, at least qualitatively, consistent with a wide variety of experimental data. The effects of environment on pitting corrosion have been included in the model using a set of simple phenomenological equations relating the parameters of the stochastic model to key ...

1993-01-01

208

Environmental mitigation for SCC initiation of BWR core internals by hydrogen injection during start-up  

Energy Technology Data Exchange (ETDEWEB)

Hydrogen injection into the reactor water has been applied to many BWR power stations. Since hydrogen injected accelerates recombination of oxidant generated by water radiolysis, oxidant concentration, such as dissolved oxygen concentration in reactor water can be reduced. As the result of the reduction of oxidant concentration, Electrochemical Corrosion Potential (ECP) at the surface of structural material can be lowered. Lowered ECP moderates Stress Corrosion Cracking (SCC) sensitivity of structural materials, such as stainless steels. As usual, hydrogen injection system begins to work after the plant start-up is finished, when the condition of normal operation is established. Accordingly, Hydrogen Water Chemistry (HWC) does not cover all the period of plant operation. As far as SCC crack growth is considered, loss of HWC during plant start-up does not result in significant crack growth, because of duration of plant ...

2004-07-01

209

Effect of lead exposure in children  

International Nuclear Information System (INIS)

Increasing prosperity and population-growth in many developing countries are resulting in accelerated growth in population of vehicles and vehicle-kilometers traveled. In Pakistan also, the number of vehicles has jumped from 0.8 million to about 4.0 million within 20 years, showing an overall increase of more than 400%. Accordingly, the consumption of petrol (motor spirit) has increased from 828,670 metric tons to 1,189,042 metric tons. The high content of lead in petrol is a serious issue, as the end- product is the release of lead into the environment. In Pakistan, prior to July 2001, lead-content in petrol was reported to be as high as 0.35-0.84 gram per liter. The reported lead-levels in air (micrograms/cubic centimeter) in different cities of Pakistan are: Karachi (1980-81) 0.13-0.24; Peshawar (1994-95) 0.21-0.79; Lahore (1993-94) 0.15-8.36 and (1999-2000) 0.89-7.85 and Rawalpindi (1999-2000) 0.71-10.00, indicating the ...

210

IFA-2 collective ion accelerator experiments  

Energy Technology Data Exchange (ETDEWEB)

Ion acceleration has now been demonstrated with the IFA-2 collective ion accelerator system. The IFA-2 system is described, photoionization experiments are summarized, and ion results are presented. Using a 1 MeV electron beam and a 30 cm acceleration length, IFA-2 has produced 5 MeV H/sup +/, 10 MeV D/sup +/, and 20 MeV He/sup + +/. This means that accelerating fields of 33 MV/m over 30 cm have been achieved with a controlled collective accelerator for the first time.

1985-10-01

211

Proposal for the award of a blanket purchase contract for the supply of electronics subracks for the CERN accelerator control system  

CERN Document Server

Proposal for the award of a blanket purchase contract for the supply of electronics subracks for the CERN accelerator control system

2010-01-01

212

Background information on the high energy physics program and the proposed Stanford linear electron accelerator project  

CERN Document Server

Background information on the high energy physics program and the proposed Stanford linear electron accelerator project

1961-01-01

213

Accelerator technology program, January-June 1982. Status report  

International Nuclear Information System (INIS)

The major projects of the Los Alamos National Laboratory's Accelerator Technology Division are discussed, covering activities that occurred during the first six months of calendar 1982.

215

Influence of a combination of two tetrachlorobiphenyl congeners (PCB 47; PCB 77) on thyroid status, choline acetyltransferase (ChAT) activity, and short- and long-term memory in 30-day-old Sprague-Dawley rats  

International Nuclear Information System (INIS)

The important role of thyroid hormones in growth and development, maintenance of body temperature, digestion, cardiac function, and normal brain development can be disrupted by environmental contaminants like polychlorinated biphenyls (PCB). Polychlorinated biphenyls are environmental contaminants that are widespread, persistent, lipophilic, and bioaccumulate through food webs, concentrating in adipose tissue. Placental and lactational PCB exposure of offspring causes metabolic and endocrine disruptions including hypothyroxinemia, spatial learning and memory deficits, neurochemical and neurobehavioral alterations, and reproductive problems. Previous studies in our lab using the individual congeners PCB 47 (2,2',4,4'-tetrachlorobiphenyl, ortho-substituted) and PCB 77 (3,3',4,4'-tetrachlorobiphenyl, non-ortho-substituted) have demonstrated alterations in thyroid hormone levels, alterations in brain choline acetyltransferase (ChAT) activity, and spatial learning ...

2004-10-15

216

Endovascular transplantation of stem cells to the injured rat CNS  

Energy Technology Data Exchange (ETDEWEB)

Transplantation procedures using intraparenchymal injection of stem cells result in tissue injury in addition to associated surgical risks. Intravenous injection of mesenchymal stem cells gives engraftment to lesions, but the method has low efficiency and specificity. In traumatic brain injuries (TBI), there is a transient breakdown of the blood-brain barrier and an inflammatory response, which increase migration of cells from blood to parenchyma. The aim of this investigation was to analyze the effect of intra-arterial administration on cellular engraftment. Experimental TBI was produced in a rat model. Endovascular technique was used to administer human mesenchymal stem cells in the ipsilateral internal carotid artery. Evaluation of engraftment and side effects were performed by immunohistochemical analysis of the brain and several other organs. The results were compared to intravenous administration of ...

2009-10-15

221

Biochemical characterization of the molecular interaction between recombinant basic fibroblast growth factor and a recombinant soluble fibroblast growth factor receptor.  

UK PubMed Central (United Kingdom)

The extracellular domain of human fibroblast growth factor receptor (XC-FGF-R) was expressed in Escherichia coli. The protein was purified to homogeneity and the interaction with basic fibroblast growth...Full Text Available

1993-09-15

222

Kinetic Roughening and Energetics of Tetragonal Lysozyme Crystal Growth  

Science.gov (United States)

Lysozyme crystal growth rates over 5 orders of magnitude in range can be described using a

2003-01-01

223

Thyroid cancer stem cells  

British Library Electronic Table of Contents (United Kingdom)

Thyroid cancer is the most frequently diagnosed endocrine cancer and causes more deaths than all other endocrine cancers combined. Research findings support the concept that a subpopulation of thyroid cancer cells displays properties characteristic of stem cells. These putative cancer-forming entities drive tumorigenesis as a result of their dual ability to undergo self-renewal and to differentiate into various types of cancer cells; they also mediate metastasis and are resistant to the effects of chemotherapy and radiation therapy. This Review discusses the cellular origin of thyroid cancer and the properties of the thyroid cancer stem cell niche. The article critically evaluates the methods used to identify molecular markers expressed by thyroid-cancer-initiating cells and outlines prosp...

2011-01-01

224

Long-Term Follow-Up of Patients with Breast Cancer Transplanted with Autologous Ex Vivo Expanded Peripheral Blood Progenitor Cells  

British Library Electronic Table of Contents (United Kingdom)

Ex vivo expanded peripheral blood progenitor cells (PBPC) have been shown to provide rapid neutrophil engraftment, and in some patients, to eliminate neutropenia after transplantation to support high-dose chemotherapy. However, the effect of expansion culture on stem cell content and potential loss of stem cells caused by induction of differentiation remains a concern. We have transplanted 21 patients with breast cancer with expanded autologous PBPC, with 11 patients receiving expanded PBPC as their sole hematopoietic cell source. In these studies, the CD34+ cells were selected and cultured for 10 days in defined media containing 100 ng/mL each of recombinant human stem cell factor (rhSCF), recombinant human granulocyte colony stimulating factor (rhG-CSF), and recombinant human megakaryocy...

2006-01-01

225

Immunomodulatory strategies for relapse after haploidentical hematopoietic stem cell transplantation in hematologic malignancy patients  

British Library Electronic Table of Contents (United Kingdom)

Currently, human leukocyte antigen (HLA)-mismatched/haploidentical allografts have been validated as an alternative stem cell source for patients who have no immediate access to an HLA-matched related or unrelated donor. However, relapse remains a challenge after HLA-mismatched/haploidentical hematopoietic stem cell transplantation (HSCT) that is employed in the treatment of patients with hematological malignancies. In recent years, newly developed immunomodulatory strategies, which include prophylactic and therapeutic donor lymphocyte/natural killer (NK) cell infusion, donor selection based on NK alloreactivity/non-inherited maternal antigen (NIMA), immune reconstitution promotion, and application of exogenous cytokines, have made it possible to decrease the relapse rate and improve outco...

2011-01-01

226

Functionally defined substates within the human embryonic stem cell compartment.  

Science.gov (United States)

Human embryonic stem (ES) cells can undergo spontaneously differentiation in standard culture conditions, demonstrating that the undifferentiated state is relatively unstable. The heterogeneous expression of SSEA3 observed within human ES colonies, provides a means to examine undifferentiated stem cell substates. Through functional testing of single cells we have shown that undifferentiated ES cells can be segregated into functionally discrete subpopulations on the basis of SSEA3 expression: SSEA3(High), SSEA(Low) and SSEA3(Negative). Human ES subpopulations were found to be interconvertible, but they possess distinct properties when challenged to differentiate along the neural lineage. These data suggest that ES cells with pluripotent/self-renewal capacities can exhibit different responses to induction of differentiation. PMID:21763622

2011-05-11

227

Enhanced osteogenic differentiation of cord blood-derived unrestricted somatic stem cells on electrospun nanofibers  

British Library Electronic Table of Contents (United Kingdom)

A new stem cell-scaffold construct based on poly-l-lactide (PLLA) nanofibers grafted with collagen (PLLA-COL) and cord blood-derived unrestricted somatic stem cells (USSC) were proposed to hold promising characteristics for bone tissue engineering. Fabricated nanofibers were characterized using SEM, ATR-FTIR, tensile and contact angle measurements. The capacity of PLLA, plasma-treated PLLA (PLLA-pl) and PLLA-COL scaffolds to support proliferation and osteogenic differentiation of USSC was evaluated using MTT assay and common osteogenic markers such as alkaline phosphatase (ALP) activity, calcium mineral deposition and bone-related genes. All three scaffolds showed nanofibrous and porous structure with suitable physical characteristics. Higher proliferation and viability of USSC was observe...

2011-01-01

229

Status of LBL/LLNL FEL (free electron laser) research for two beam accelerator applications  

Energy Technology Data Exchange (ETDEWEB)

We review the status of free electron laser (FEL) research being conducted at LBL and LLNL as part of a broader program of research on two beam accelerators (TBAs). Induction accelerator-driven FELs for use as power sources for high-gradient accelerators are discussed, along with preliminary cost estimates for this type of power source. Finally, a promising new version of an FEL/TBA is described. 25 refs., 1 fig., 3 tabs.

1989-03-01

230

ISR site  

CERN Document Server

A last look at the green field, in the triangular wedge of land stray radiation near the CERN accelerators.

1965-01-01

231

IEE, accelerated waste mgt, McM  

Science.gov (United States)

... in ATCM Recommendation XIV-2. The USAP's materials and waste management efforts are consistent with ...

233

Foreign Affair's: Fool's Gold  

Wastenet

aged gracefully: premature and accelerated corro - sion, erosion, and stress are raising maintenance costs.Last

235

Biophotonics and Bone Biology  

Science.gov (United States)

One of the more-serious side effects of extended space flight is an accelerated bone loss

2004-01-01

236

PIC Simulations Of Ion Acceleration By Linearly And Circularly Polarized Laser Pulses  

Science.gov (United States)

Linearly polarized laser radiation accelerates electrons to very high velocities and these electron form a sheath layer on the rear side of thin targets where preferentially protons are accelerated. When mass-limited targets are used, the lateral transport of the absorbed laser energy is reduced and the accelerating field is enhanced. For targets consisting of two ion species, heavier ions facilitate formation of quasi-monoenergetic bunch of lighter ions. For circularly polarized light, fast electron production is suppressed by the absence of the oscillatory component of the ponderomotive force. Ions are accelerated on the front side by the separation field and very thin foil can be accelerated as one massive quasi-neutral block. As all ion species acquire the same velocity, this acceleration mechanism is preferred for heavier ions.

2008-06-24

237

Evaluation of the residual radiation field in the proton accelerator facility of the Proton Engineering Frontier Project (PEFP) in Korea  

British Library Electronic Table of Contents (United Kingdom)

In Korea, the Proton Engineering Frontier Project (PEFP) is building a proton linear accelerator facility with energy up to 100MeV and a beam current of 20mA. In this study, a radiation field after shutdown in the accelerator facility of the PEFP was evaluated for the purpose of the radiation shielding by using MCNPX code. A facility modeling was performed for the accelerator tunnel building, accelerator chain, target rooms and beam experiment hall. And radiation source terms were evaluated in the facility. With this facility, model and radiation source terms, the concentration of 41Ar was evaluated and the cooling time satisfying regulation in Korea was calculated.

2007-01-01

238

Collective ion acceleration in systems with a virtual cathode  

International Nuclear Information System (INIS)

The current status of research and development in the realm of physics and technology of collective ion acceleration in systems with a virtual cathode (VC) is reviewed. Three major acceleration methods and devices developed on their basis are considered: reflex triodes and their modifications, gas-filled vircators, and vacuum vircators with a Luce diode. Experimental data are outlined and the principal physical models interpreting these data are described. New ion acceleration techniques whose realization involves the production and disappearance of the VC are also discussed. All methods of collective ion acceleration are compared and the possible ways for the further development of this promising scientific field are highlighted. (reviews of topical problems)

2002-11-30

239

Ultrasonic Acoustic Emissions from the Sapwood of Thuja occidentalis Measured inside a Pressure Bomb 1  

UK PubMed Central (United Kingdom)

An improved method of counting acoustic emission (AE) events from water-stressed stems of cedar (Thuja occidentalis L.) is presented. Amplified AEs are analyzed on a real time basis...Full Text Available

1984-04-01

240

The promises and perils of p53  

UK PubMed Central (United Kingdom)

Five studies show that disabling p53, an essential tumour-suppressor protein, improves the efficiency of stem-cell production. Are these results a ‘heads up’ that cancer cells...Full Text Available

2009-08-27

241

Stem cell niches and other factors that influence the sensitivity of bone marrow to radiation-induced bone cancer and leukaemia in children and adults  

UK PubMed Central (United Kingdom)

Purpose: This paper reviews and reassesses the internationally accepted niches or ‘targets’ in bone marrow that are sensitive to the induction of leukaemia and primary...Full Text Available

2011-04-01

242

Stem Cell Therapies Benefit Alport Syndrome  

UK PubMed Central (United Kingdom)

Patients with Alport syndrome progressively lose renal function as a result of defective type IV collagen in their glomerular basement membrane. In mice lacking the α3 chain of type IV collagen...Full Text Available

2009-11-01

243

SirT1 brings stemness closer to cancer and aging  

UK PubMed Central (United Kingdom)

Sirtuin 1 acts in various cell processes, deacetylating both chromatin and non-histone proteins, and its role in cancer and aging has long been studied and debated. Here we discuss another aspect of...Full Text Available

244

Short Stat5-Interacting Peptide Derived from Phospholipase C-?3 Inhibits Hematopoietic Cell Proliferation and Myeloid Differentiation  

UK PubMed Central (United Kingdom)

Constitutive activation of the transcription factor Stat5 in hematopoietic stem/progenitor cells leads to various hematopoietic malignancies including myeloproliferative neoplasm (MPN). Our recent study...Full Text Available

245

Relationship of Xylem Embolism to Xylem Pressure Potential, Stomatal Closure, and Shoot Morphology in the Palm Rhapis excelsa1  

UK PubMed Central (United Kingdom)

Xylem failure via gas embolism (cavitation) induced by water stress was investigated in the palm Rhapis excelsa (Thumb.) Henry. Xylem embolism in excised stems and petioles was detected...Full Text Available

1986-01-01

246

RNA expression in a cartilaginous fish cell line reveals ancient 3? noncoding regions highly conserved in vertebrates  

UK PubMed Central (United Kingdom)

We have established a cartilaginous fish cell line [Squalus acanthias embryo cell line (SAE)], a mesenchymal stem cell line derived from the embryo of an elasmobranch, the spiny dogfish...Full Text Available

2007-01-23

247

Putative intermediates in the nerve cell differentiation pathway in hydra have properties of multipotent stem cells  

Energy Technology Data Exchange (ETDEWEB)

We have investigated the properties of nerve cell precursors in hydra by analyzing the differentiation and proliferation capacity of interstitial cells in the peduncle of Hydra oligactis, which is a region of active nerve cell differentiation. Our results indicate that about 50% of the interstitial cells in the peduncle can grow rapidly and also give rise to nematocyte precursors when transplanted into a gastric environment. If these cells were committed nerve cell precursors, one would not expect them to differentiate into nematocytes nor to proliferate apparently without limit. Therefore we conclude that cycling interstitial cells in peduncles are not intermediates in the nerve cell differentiation pathway but are stem cells. The remaining interstitial cells in the peduncle are in G1 and have the properties of committed nerve cell precursors. Thus, the interstitial cell population in the peduncle contains both stem cells and noncycling nerve ...

1990-12-01

248

Probing a Membrane Matrix Regulating Hormone Action  

UK PubMed Central (United Kingdom)

Auxin-induced pea (Pisum sativum) stem section elongation is enhanced at levels of 3 to 40 micromolar by six new classes of alkane derivatives additional to those described earlier,...Full Text Available

1971-11-01

249

Osterix Overexpression in Mesenchymal Stem cells Stimulates Healing of Critical-Sized Defects in Murine Calvarial Bone  

UK PubMed Central (United Kingdom)

Osterix (Osx) is a zinc-finger-containing transcription factor that is expressed in osteoblasts of all endochondral and membranous bones. In Osx null ...Full Text Available

2007-10-01

250

Non-Invasive Stem Cell Therapy in a Rat Model for Retinal Degeneration and Vascular Pathology  

UK PubMed Central (United Kingdom)

BackgroundRetinitis pigmentosa (RP) is characterized by progressive night blindness, visual field loss, altered vascular permeability and loss of central vision. Currently there...Full Text Available

251

Muscle satellite cell proliferation and association: new insights from myofiber time-lapse imaging  

UK PubMed Central (United Kingdom)

BackgroundAs the resident stem cells of skeletal muscle, satellite cells are activated by extracellular cues associated with local damage. Once activated, satellite cells will re-enter...Full Text Available

252

Monovalent and unpoised status of most genes in undifferentiated cell-enriched Drosophila testis  

UK PubMed Central (United Kingdom)

BackgroundIncreasing evidence demonstrates that stem cells maintain their identities by a unique transcription network and chromatin structure. Opposing epigenetic modifications...Full Text Available

2010-01-01

253

Methyl Jasmonate Induces Traumatic Resin Ducts, Terpenoid Resin Biosynthesis, and Terpenoid Accumulation in Developing Xylem of Norway Spruce Stems1  

UK PubMed Central (United Kingdom)

Norway spruce (Picea abies L. Karst) produces an oleoresin characterized by a diverse array of terpenoids, monoterpenoids, sesquiterpenoids, and diterpene resin acids that can protect...Full Text Available

2002-07-01

254

Loss of Function of E-Cadherin in Embryonic Stem Cells and the Relevance to Models of Tumorigenesis  

UK PubMed Central (United Kingdom)

E-cadherin is the primary cell adhesion molecule within the epithelium, and loss of this protein is associated with a more aggressive tumour phenotype and poorer patient prognosis in many cancers. Loss...Full Text Available

2011-01-01

255

Lnk controls mouse hematopoietic stem cell self-renewal and quiescence through direct interactions with JAK2  

UK PubMed Central (United Kingdom)

In addition to its role in megakaryocyte production, signaling initiated by thrombopoietin (TPO) activation of its receptor, myeloproliferative leukemia virus protooncogene (c-Mpl, or Mpl), controls...Full Text Available

2008-08-01

256

Lnk constrains myeloproliferative diseases in mice  

UK PubMed Central (United Kingdom)

Hematopoietic stem and progenitor cell (HSPC) expansion is regulated by intrinsic signaling pathways activated by cytokines. The intracellular kinase JAK2 plays an essential role in cytokine signaling,...Full Text Available

2010-06-01

257

K Kiosk - NIH Extramural Training: Information about NIH Career...  

Science.gov (United States)

Established Investigators (K18) (PAR-09-090) NIH: Career Enhancement Award for Stem Cell Research (K18) (PA-09-110) NIDCD: NIDCD Research Career Enhancement Award for Established...

2011-10-01

258

Identification of Human Prostate Cancer Stem Cells by ...  

Science.gov (United States)

... The basal markers CK5, alpha 6 integrin (CD49f), CD44, and p63 were strongly expressed by the majority of sphere-forming cells. ... p63 p63 PSCA ...

2008-04-01

259

Gravitropism in Higher Plant Shoots 1  

UK PubMed Central (United Kingdom)

Although the Cholodny-Went model of auxin redistribution has been used to explain the transduction phase of gravitropism for over 60 years, problems are apparent, especially with dicot stems. An alternative...Full Text Available

1989-12-01

260

Gravitropism in Higher Plant Shoots 1  

UK PubMed Central (United Kingdom)

Ethylene at 1.0 and 10.0 cubic centimeters per cubic meter decreased the rate of gravitropic bending in stems of cocklebur (Xanthium strumarium L.) and tomato (Lycopersicon...Full Text Available

1986-10-01

261

Efferent Control of Hair Cell and Afferent Responses in the Semicircular Canals  

UK PubMed Central (United Kingdom)

The sensations of sound and motion generated by the inner ear are controlled by the brain through extensive centripetal innervation originating within the brain stem. In the semicircular canals, brain...Full Text Available

2009-09-01

262

Effects of Human Adipose-derived Stem Cells on Cutaneous Wound Healing in Nude Mice  

UK PubMed Central (United Kingdom)

BackgroundDespite numerous treatments available for deteriorated cutaneous wound healing such as a diabetic foot, there is still the need for more effective therapy. Adipose-derived...Full Text Available

2011-05-01

263

Early Post-operative Periprosthetic Femur Fracture in the Presence of a Non-cemented Tapered Wedge Femoral Stem  

UK PubMed Central (United Kingdom)

Non-cemented femoral fixation in hip arthroplasty has become the standard of practice in the USA. However, recent literature has brought attention to an increasing incidence of periprosthetic femur...Full Text Available

2010-09-01

264

Drosophila neuroblasts retain the daughter centrosome  

UK PubMed Central (United Kingdom)

During asymmetric mitosis, both in male Drosophila germline stem cells and in mouse embryo neural progenitors, the mother centrosome is retained by the self-renewed cell; hence suggesting...Full Text Available

265

Biotin-labeled hairpin oligonucleotides: probes to detect double-strand breaks in DNA in apoptotic cells.  

UK PubMed Central (United Kingdom)

Hairpin oligonucleotides were synthesized with stems ending in a double-stranded structure, which can be ligated to double-strand breaks in DNA, and with loops that contain nucleotides modified by the...Full Text Available

1998-04-01

266

Acetic Acid Bacterial Biota of the Pink Sugar Cane Mealybug, Saccharococcus sacchari, and Its Environs  

UK PubMed Central (United Kingdom)

Saccharococcus sacchari is the primary colonizer of the developing “sterile” tissue between the leaf sheath and stem of sugar cane. The honeydew secreted by the mealybugs...Full Text Available

1990-03-01

267

A piggyBac transposon-based genome-wide library of insertionally mutated Blm-deficient murine ES cells  

UK PubMed Central (United Kingdom)

Cultured mouse or human embryonic stem (ES) cells provide access to all of the genes required to elaborate the fundamental components and physiological systems of a mammalian cell. Chemical or insertional...Full Text Available

2009-04-01

268

A highly conserved regulatory element controls hematopoietic expression of GATA-2 in zebrafish  

UK PubMed Central (United Kingdom)

BackgroundGATA-2 is a transcription factor required for hematopoietic stem cell survival as well as for neuronal development in vertebrates. It has been shown that specific expression...Full Text Available

269

A gene expression signature shared by human mature oocytes and embryonic stem cells  

UK PubMed Central (United Kingdom)

BackgroundThe first week of human pre-embryo development is characterized by the induction of totipotency and then pluripotency. The understanding of this delicate process will have...Full Text Available

270

Semiquantitative measure of immune responses against erythropoietic stem cell antigens  

Energy Technology Data Exchange (ETDEWEB)

A semiquantitative assay was developed and used to measure the effects of immune responses against 16 independent non-H-2 antigenic loci on erythropoietic stem cells. The assay compares repopulation in genetically anemic WBB6F1-W/Wv recipients that have normal immune responses, and in lethally irradiated WBB6F1 +/+ mice whose immune responses are suppressed by the irradiation. The differences in repopulating ability between these two types of recipients measure how immune responses affect erythropoietic stem cells. Stem cell repopulating abilities for the cells with antigens specified by the Thy-1, H-1, H-24, Ly-1, H-37, and H-17 loci were affected slightly, if at all. Repopulating abilities were moderately reduced by responses against antigens specified by H-15, 16, Ea-2, and Ly-2, 3 loci, and against the differences between the B6 and B10 genotypes, although marrow of these types cured W/Wv recipients. A surprising result ...

1987-01-01

271

Brazing techniques for side-coupled electron accelerator structures  

Energy Technology Data Exchange (ETDEWEB)

The collaboration between the Los Alamos National Laboratory and the National Bureau of Standards (NBS), started in 1979, has led to the development of an advanced c-w microtron accelerator design. The four 2380-MHz NBS accelerating structures, containing a total of 184 accelerating cavities, have been fabricated and delivered. New fabrication methods, coupled with refinements of hydrogen-furnace brazing techniques described in this paper, allow efficient production of side-coupled structures. Success with the NBS RTM led to Los Alamos efforts on similar 2450-MHz accelerators for the microtron accelerator operated by the Nuclear Physics Department of the University of Illinois. Two accelerators (each with 17 cavities) have been fabricated; in 1986, a 45-cavity accelerator is being fabricated by private industry with some assistance from Los ...

1986-01-01

272

Electron accelerators, present and future applications  

International Nuclear Information System (INIS)

The development and occurrence of new electron accelerators and applications are according to the human society development law, as a whole. The period of economic standstill is generating an intense creative activity in the domain of science and engineering which also resulting in great achievements in the field of electron accelerators. This paper presents the basic principle of the electron beam applications and the accelerators required characteristics for their present and potential applications in the domains: radiation sources, diagnostics, radiation processing, energetics, environment, defense and basic sciences. All these are correlated to the new generation of accelerators which, for the acceleration process, may employ electromagnetic fields generated by standard sources, atomic lasers, free electron lasers, Cerenkov effect, Smith - Purcell effect, electron beams, plasma, ...

273

Smith-Purcell free-electron laser  

International Nuclear Information System (INIS)

The term Smith-Purcell free electron laser can be employed generally to describe any coherent radiation source in which a diffraction grating is used to couple an electron beam with the electromagnetic field. To date, most practical developments of this concept have focused on devices which operate in the millimeter spectral regime. In this paper construction of a Smith-Purcell free-electron laser operating in the far-infrared (FIR) region using a novel resonator cavity design and the electron beam from a low energy (0.5-5 MeV) radio-frequency accelerator will be discussed. A tunable source in this region would have many applications and since the beam energy is low, the small size and low overall cost of such a device would make it a laboratory instrument. Current projects which are progressing towards developing a FIR source are the programs at Stanford and CREOL. Both of these projects are using permanent magnet undulators to couple the electron beam with the ...

1995-08-21

274

Residual #alpha#-Si_3N_4 in O' crystals in CeO_2-doped O' + #beta#' SiAlON ceramics  

International Nuclear Information System (INIS)

The microstructure of a pressureless sintered (1,605 C, 90 min) O' + #beta#' SiAlON ceramic with CeO_2 doping has been investigated. It is duplex in nature, consisting of very large, slablike elongated O' grains (20--30 #mu#m long), and a continuous matrix of small rodlike #beta#' grains (< 1.0 #mu#m in length). Many #alpha#-Si_3N_4 inclusions (0.1--0.5 #mu#m in size) were found in the large O' grains. CeO_2-doping and its high doping level as well as the high Al_2O_3 concentration were thought to be the main reasons for accelerating the reaction between the #alpha#-Si_3N_4 and the Si-Al-O-N liquid to precipitate O'-SiAlON. This caused the supergrowth of O' grains. The rapid growth of O' crystals isolated the remnant #alpha#-Si_3N_4 from the reacting liquid, resulting in a delay in the #alpha# #-># #beta#-Si_3N_4 transformation. The large O' grains and the #alpha#-Si_3N_4 inclusions have a pronounced effect on the strength degradation of ...

275

Development of materials resistant to metal dusting degradation.  

Energy Technology Data Exchange (ETDEWEB)

Metal dusting corrosion has been a serious problem in the petroleum and petrochemical industries, such as reforming and syngas production systems. This form of deterioration has led to worldwide material loss for 50 years. For the past three years, we have studied the mechanism of metal dusting for Fe- and Ni-base alloys. In this report, we present a correlation between the weight loss and depth of pits that form in Ni-base alloys. Nickel-base alloys were also tested at 1 and 14.8 atm (210 psi), in a high carbon activity environment. Higher system pressure was found to accelerate corrosion in most Ni-base alloys. To reduce testing time, a pre-pitting method was developed. Mechanical scratches on the alloy surface led to fast metal dusting corrosion. We have also developed preliminary data on the performance of weldments of several Ni-base alloys in a metal dusting environment. Finally, Alloy 800 tubes and plates used in a reformer plant were examined by scanning ...

2006-04-24

276

U of C site vies for new particle accelerator  

CERN Multimedia

"American dominance in the study and development of high-energy particle physics may be seriously compromised, according to a report issued by the National Academy of Sciences, unless efforts are made to ensure that the next high-energy particle accelerator - the International Linear Collider (ILC) - will be constructed in the U.S.

2006-01-01

277

Maximum proton kinetic energy and patient-generated neutron fluence considerations in proton beam arc delivery radiation therapy  

UK PubMed Central (United Kingdom)

Several compact proton accelerator systems for use in proton therapy have recently been proposed. Of paramount importance to the development of such an accelerator system is the maximum kinetic energy...Full Text Available

2009-02-01

278

Knockout of Arabidopsis ACCELERATED-CELL-DEATH11 encoding a sphingosine transfer protein causes activation of programmed cell death and defense  

UK PubMed Central (United Kingdom)

We describe the lethal, recessive accelerated-cell-death11 Arabidopsis mutant (acd11). Cell death in acd11 exhibits characteristics of animal apoptosis...Full Text Available

2002-02-15

279

Heavy-ion linear induction accelerators as drivers for inertial fusion power plants  

Energy Technology Data Exchange (ETDEWEB)

A linear induction accelerator that produces a beam of energetic heavy ions (T -- 10 GeV, A -- 200 amu) is a prime candidate as a driver for an inertial fusion power plant. Some early perceptions were that heavy-ion drive fusion would not be cost-competitive with other power sources because of the high cost of the accelerators. However, improved understanding of the physics of heavy-ion transport and acceleration (supported by experimental results), combined with advances in accelerator technology, have resulted in accelerator design costs -- 50% of previous estimates. As a result, heavy-ion drive fusion power plants are now projected to be cost-competitive with other conceptual fusion power plants. A brief formulation of transport and acceleration physics is presented here, along with a description of the induction Linac cost optimization code LIACEP. Cost ...

1988-02-01

280

Heavy-ion linear induction accelerators as drivers for inertial fusion power plants  

International Nuclear Information System (INIS)

A linear induction accelerator that produces a beam of energetic heavy ions (T #approx =# 10 GeV, A #approx =# 200 am#mu#) is a prime candidate as a driver for an inertial fusion power plant. Some early perceptions were that heavy-ion driven fusion would not be cost-competitive with other power sources because of the high cost of the accelerators. However, improved understanding of the physics of heavy-ion transport and acceleration (supported by experimental results), combined with advances in accelerator technology, have resulted in accelerator design costs -- 50% of previous estimates. As a result, heavy-ion driven fusion power plants conceptual fusion power plants. A brief formulation of transport and acceleration physics is presented here, along with a description of the induction Linac cost optimization code LIACEP. Cost trends are presented and discussed, ...

281

Development of an Accelerated Weathering Protocol using Weatherometers for Reliability Study of Mini-Modules and Encapsulation Materials  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the needs, reasoning, approaches, and technical details to establish a practical accelerated weathering test (AWT) protocol for indoor testing of the photothermal stability of encapsulation materials and encapsulated solar cells and minimodules.

2000-01-01

282

Beam-forming system for electrostatic accelerator  

International Nuclear Information System (INIS)

A simple beam-forming system is described for the electrostatic accelerator of the Scientific-Research Institute of Nuclear Physics of Moscow State University. The system allows the beam to be focused on targets at various distances for a conductor potential of from 1 to 4 MV and beam currents of up to 35 #mu# A.

1988-01-01

283

Analytical validation of accelerator mass spectrometry for pharmaceutical development  

UK PubMed Central (United Kingdom)

The validation parameters for pharmaceutical analyses were examined for the accelerator mass spectrometry measurement of 14C/C ratio, independent of chemical separation procedures....Full Text Available

2010-03-01

284

Accelerator technology program, January-June 1982. Status report  

Science.gov (United States)

The major projects of the Los Alamos National Laboratory's Accelerator Technology Division are discussed, covering activities that occurred during the first six months of calendar 1982.

1983-12-01

285

Accelerator aspects of #gamma#-#gamma# colliders  

International Nuclear Information System (INIS)

There are several on-going projects of e"+e"- colliders. If they are constructed, we can convert them into photon-photon (#gamma#-#gamma#) colliders by converting electron beams into #gamma# beams, irradiating laser beams just before the interaction point. In this report we discuss the technical issues on the accelerator.

2000-11-21

286

Accelerated surgical stay programs. A mechanism to reduce health care costs.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To increase cost-efficiency while maintaining the standard of medical care, an accelerated surgical stay program for patients having breast surgery was instituted. SUMMARY BACKGROUND DATA:...Full Text Available

1994-04-01

287

Regulation of rat hepatic low density lipoprotein receptors. In vivo stimulation by growth hormone is not mediated by insulin-like growth factor I.  

UK PubMed Central (United Kingdom)

Growth hormone (GH) has an important role in the regulation of hepatic LDL receptor expression and plasma lipoprotein levels. This investigation was undertaken to evaluate if these effects of GH on...Full Text Available

1996-01-15

288

Rapamycin inhibits trypanosome cell growth by preventing TOR complex 2 formation  

UK PubMed Central (United Kingdom)

Target of rapamycin (TOR) kinases control cell growth through two functionally distinct multiprotein complexes. TOR complex 1 (TORC1) controls temporal cell growth and is sensitive to rapamycin, whereas...Full Text Available

2008-09-23

289

Electrogenic malate uptake and improved growth energetics of the malolactic bacterium Leuconostoc oenos grown on glucose-malate mixtures.  

UK PubMed Central (United Kingdom)

Growth of the malolactic bacterium Leuconostoc oenos was improved with respect to both the specific growth rate and the biomass yield during the fermentation of glucose-malate mixtures as compared with...Full Text Available

1992-08-01

290

Cell kinetics of growth cartilage of achondroplastic (cn) mice.  

UK PubMed Central (United Kingdom)

Mice homozygous for the recessive gene achondroplasia (cn) aged 16 and 17 days and some homozygotes aged 22-34 days have disruptions in the growth of the proximal tibial growth plate which are due solely...Full Text Available

1985-05-01

291

A Patchy Growth via Successive and Simultaneous Cambia: Key to Success of the Most Widespread Mangrove Species Avicennia marina?  

UK PubMed Central (United Kingdom)

Background and AimsSecondary growth via successive cambia has been intriguing researchers for decades. Insight into the mechanism of growth layer formation is, however, limited to...Full Text Available

2008-01-01

292

The joint project for high-intensity proton accelerators  

Energy Technology Data Exchange (ETDEWEB)

Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting the joint project integrating both the Neutron Science Project (NSP) of JAERI and the Japan Hadron Facility Project (JHF) of KEK for comprehensive studies on basic science and technology using high-intensity proton accelerator. This document describes the joint project prepared by the Joint Project Team of JAERI and KEK to construct accelerators and research facilities necessary both for the NSP and the JHF at the site of JAERI Tokai Establishment. It was originally written in English and translated into Japanese with some corrections. (author)

2000-02-01

293

Operational status of the Brookhaven National Laboratory Accelerator Test Facility  

International Nuclear Information System (INIS)

Initial design parameters and early operational results of a 50 MeV high brightness electron linear accelerator are described. The system utilizes a radio frequency electron gun operating at a frequency of 2.856 GHz and a nominal output energy of 4.5 MeV followed by two, 2#pi#/3 mode, disc loaded, traveling wave accelerating sections. The gun cathode is photo excited with short (6 psec) laser pulses giving design peak currents of a few hundred amperes. The system will be utilized to carry out infra-red FEL studies and investigation of new high gradient accelerating structures.

1990-06-11

295

Improved four-stage accel-decel production of low energy highly stripped heavy ions  

Energy Technology Data Exchange (ETDEWEB)

The two model MP Tandem Van de Graaff accelerators at Brookhaven have been used in a four-stage accel-decel configuration to produce highly stripped low energy heavy ions. The performance in this mode of operation has now been substantially improved by modifications of the second accelerator. The inclined field acceleration tube electrodes at the exit of this accelerator were replaced by straight electrodes, the vacuum was improved and the maximum negative terminal potential was increased. Higher intensity beams of heavier highly stripped ions can now be produced at lower energies than before.

1983-04-01

296

Heavy-ion accelerators and predicted lifetimes of highly stripped ions  

International Nuclear Information System (INIS)

(Sep 1973). United Kingdom Sinanoglu, O. Luken, W. Yale Univ., New Haven,

1973-01-01

298

Design of a tandem accelerator free electron laser  

International Nuclear Information System (INIS)

The motivation for using a tandem electrostatic accelerator as an electron accelerator for a free electron laser (FEL) is presented. The adaptation of the HVEC EN tandem at the Weizmann Institute for this purpose, electron beam optics and nonlinear FEL computation relevant for this FEL realization are described. In the tandem configuration the terminal is held at a positive potential. The electron beam is accelerated from ground potential to the terminal in one beam tube and then decelerated down the other beam tube. The FEL wiggler and cavity are at the terminal. Due to the beam energy recovery this scheme produces a high power beam at the terminal with a small investment in electrical power. (orig.).

299

Beam stability study based on the beam trajectory jitter in the KEKB injector linac  

International Nuclear Information System (INIS)

... Tsukuba, Ibaraki (Japan) 389 p. PARTICLE ACCELERATORS beam monitoring

2001-08-01

300

Accelerated aging tests for radiation degradation of organic materials  

International Nuclear Information System (INIS)

(Jun 1984). United States Clough, RL Gillen, KT Sandia Nat'l Laboratories

1984-06-03

301
302

Effects on fatigue life of gate valves due to higher torque switch settings during operability testing  

Energy Technology Data Exchange (ETDEWEB)

Some motor operated valves now have higher torque switch settings due to regulatory requirements to ensure valve operability with appropriate margins at design basis conditions. Verifying operability with these settings imposes higher stem loads during periodic inservice testing. These higher test loads increase stresses in the various valve internal parts which may in turn increase the fatigue usage factors. This increased fatigue is judged to be a concern primarily in the valve disks, seats, yokes, stems, and stem nuts. Although the motor operators may also have significantly increased loading, they are being evaluated by the manufacturers and are beyond the scope of this study. Two gate valves representative of both relatively weak and strong valves commonly used in commercial nuclear applications were selected for fatigue analyses. Detailed dimensional and test data were available for both valves from previous studies ...

1995-12-01

303

Explosive acceleration of liquid from a cylindrical container using the implosive technique  

British Library Electronic Table of Contents (United Kingdom)

Tthe acceleration of a liquid from a cylindrical container by the products of instantaneous detonation of a superimposed explosive charge (implosion method) is studies numerically in a two-dimensional formulation. Analytical formulas for the asymptotic velocities of liquid expansion and acceleration of the container body were obtained using numerical calculations in a one-dimensional approximation. The effect of the fracture of the body on the velocity of liquid expansion was studied in a two-dimensional formulation.

2011-01-01

304

Enabling Technologies for Petascale Electromagnetic Accelerator Simulation  

Energy Technology Data Exchange (ETDEWEB)

The SciDAC2 accelerator project at SLAC aims to simulate an entire three-cryomodule radio frequency (RF) unit of the International Linear Collider (ILC) main Linac. Petascale computing resources supported by advances in Applied Mathematics (AM) and Computer Science (CS) and INCITE Program are essential to enable such very large-scale electromagnetic accelerator simulations required by the ILC Global Design Effort. This poster presents the recent advances and achievements in the areas of CS/AM through collaborations.

2007-11-09

305

Design and fabrication of a traveling-wave muffin-tin accelerating structure at 90 GHz  

Energy Technology Data Exchange (ETDEWEB)

A prototype of a muffin-tin accelerating structure operating at 32 times the SLAC frequency (2.856 GHz) was built for research in high gradient acceleration. A traveling-wave design with single input and output feeds was chosen for the prototype which was fabricated by wire electrodischarge machining. Features of the mechanical design for the prototype are described. Design improvements are presented including considerations of cooling and vacuum.

1997-05-01

306

Symbiotic regulation of plant growth, development and reproduction  

UK PubMed Central (United Kingdom)

The growth and development of rice (Oryzae sativa) seedlings was shown to be regulated epigenetically by a fungal endophyte. In contrast to un-inoculated (nonsymbiotic) plants, endophyte...Full Text Available

2009-03-01

307

STUDY OF FAILURE AND RELIABILITY IN MICROELECTRONIC DEVICES 3rd ...  

Science.gov (United States)

It is well known that the growth of purple plague is tempera- ture dependent. in Figure 2 which shows the progressive growth of purple ...

308

Physiologic changes during growth and development.  

UK PubMed Central (United Kingdom)

To express growth-related changes in physiologic or other functions in forms usable for kinetic modeling, we are interested in identifying regular relationships that take the form of simple mathematical...Full Text Available

1994-12-01

310

Environmental and toxicological aspects of insect growth regulators.  

UK PubMed Central (United Kingdom)

Insect growth regulators (IGRs) are a class of new chemicals that interfere with maturation and reproduction in insects. Proposed hypotheses on the biochemical mechanism of action are presented herein....Full Text Available

1976-04-01

311

Effects of Yttrium Microalloying on the Epitaxial Grain Growth ...  

Science.gov (United States)

... Accession Number : ADA137272. Title : Effects of Yttrium Microalloying on the Epitaxial Grain Growth in Ti-6Al-4V Weld Fusion Zones. ...

1983-10-01

312

EFFECTS OF STERIt!ZI#C AGENTS ON HiCROOR6AIISI#S  

Science.gov (United States)

6-Mercaptopurine (6-MP) inhibits the growth of. Escherichia coli B. Growth inhibition is ... reversed by subculture of the cells in 6-mercaptopurine- ...

313

Consanguinity and fetal growth in Pakistani Moslems.  

UK PubMed Central (United Kingdom)

There is conflicting evidence about the effect of parental consanguinity on fetal growth. Previous studies have not always allowed for other factors that are known to affect birth weight, in particular,...Full Text Available

1987-03-01

314

Systematic Failure in a Stem Cell Fraud Case by a Poor Quality Culture  

International Nuclear Information System (INIS)

In the years 2004 and 2005, Korea became a prospective nation noteworthy in the world through the epochal development of genetic engineering in our country. Obstinate or incurable diseases were expected to be healed in a few years by a Korean geneticist. So many worldwide patients of obstinate or incurable diseases took notice of the research outcomes and organized an aid association to collect supporting funds. World renowned journals such as 'Nature' and 'Science' published Dr. Hwang's theses. A long and distant way remedy to obstinate diseases seemed to be closer at hand so early. However, a stem cell fraud case emerged throughout the world in late 2005, the pride of the Korean people was destroyed. With this as a momentum, voices of self reflection by scientific circles were raised. The purpose of this study is not in finding the truth of the stem cell research but to propose an effective management and control measures for the future in ...

2006-05-25

315

Long-term IL-2 therapy after transplantation of T cell depleted stem cells from alternative donors in children  

British Library Electronic Table of Contents (United Kingdom)

The aim of this pilot study was to evaluate the feasibility of long-term subcutaneous application of low-dose IL-2 in children with malignancies at very high risk of relapse who underwent highly T cell and B cell depleted HLA-identical (MUD) or full haplotype mismatched related hematopoetic stem cell transplantation. We studied 11 patients with acute leukemias/myelodysplastic syndrome and juvenile myelomonocytic leukemia (active disease and/or second stem cell transplantation, n = 8; >=CR 2, n = 2) and relapsed or progressive Ewings sarcoma (n = 2) who received prophylactic IL-2 treatment for a high probability of disease recurrence after allo-HSCT. Toxicities from IL-2 were transient fever, fatigue and local inflammation. In one patient GvHD grade III with no clear association to IL-2 adm...

2011-01-01

316

Different doses of bone morphogenetic protein 4 promote the expression of early germ cell-specific gene in bone marrow mesenchymal stem cells  

British Library Electronic Table of Contents (United Kingdom)

Bone morphogenetic protein (BMP)-4 has a crucial role on primordial germ cells (PGCs) development in vivo which can promote stem cell differentiation to PG-like cells. In this study, we investigated the expression of Mvh as one of the specific genes in primordial germ cells after treatment with different doses of BMP4 on bone mesenchymal stem cells (BMSCs)-derived PGCs. Following isolation of BMSCs from male mouse femur and tibia, cells were cultured in medium for 72?h. Passage 4 murine BMSCs were characterized by CD90, CD105, CD34, and CD45 markers and osteo-adipogenic differentiation. Different doses of BMP4 (0, 0.01, 0.1, 1, 5, 25, 50, and 100?ng/ml) were added to BMSCs for PGCs differentiation during 4-days culture. Viability percent, proliferation rates, and expression of Mvh gene wer...

2011-01-01

317

STATUS OF THE DIELECTRIC WALL ACCELERATOR  

Energy Technology Data Exchange (ETDEWEB)

The dielectric wall accelerator (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL) uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. High electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The system is capable of accelerating any charge to mass ratio particle. Applications of high gradient proton and electron versions of this accelerator will be discussed. The status of the developmental new technologies that make the compact system possible will be reviewed. These include, high gradient vacuum insulators, solid dielectric materials, photoconductive switches and compact proton sources.

2009-04-22

318

Dynamical Cycles in Charge and Energy for Iron Ions Accelerated in a Hot Plasma  

Science.gov (United States)

We consider a unified model of Fe ion acceleration in the solar corona. The model comprises charge-changing processes, Coulomb energy losses, and both regular and stochastic acceleration. At a given acceleration scenario, the type of acceleration is found to have a minor effect on the mean charge states, but the shapes of the charge-state distributions produced by regular acceleration and by stochastic acceleration are different. During a continual acceleration at coronal temperatures, iron ions typically follow rising trajectories on the charge-energy plane. These trajectories are situated below the mean equilibrium charge curve defined from the balance of ionization and recombination at fixed energy. During stopping, the iron ions cross the equilibrium charge curve and run through a series of charge states above the mean equilibrium charge ...

2001-08-01

319

Compact Dielectric Wall Accelerator Development For Intensity Modulated Proton Therapy And Homeland Security Applications  

Energy Technology Data Exchange (ETDEWEB)

Compact dielectric wall (DWA) accelerator technology is being developed at the Lawrence Livermore National Laboratory. The DWA accelerator uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. Its high electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The DWA concept can be applied to accelerate charge particle beams with any charge to mass ratio and energy. Based on the DWA system, a novel compact proton therapy accelerator is being developed. This proton therapy system will produce individual pulses that can be varied in intensity, energy and spot width. The system will be capable of being sited in a conventional linac vault and provide intensity modulated rotational therapy. The status of the developmental new ...

2009-06-17

320

Treatment of hematological malignancies with nonmyeloablative, HLA-haploidentical bone marrow transplantation and high dose, post-transplantation cyclophosphamide  

British Library Electronic Table of Contents (United Kingdom)

Hematopoietic stem cell transplantation provides the only potential curative option in many patients with hematological malignancies. Finding a suitably matched donor in a timely manner is often difficult. However, most patients have a partially HLA-mismatched (HLA-haploidentical) first-degree relative readily available. Historically, HLA-haploidentical bone marrow transplantation (BMT) has been considered extremely high risk due to high rates of life-threatening graft-versus-host disease (GVHD) and non-relapse mortality (NRM). Modifications of the stem cell graft, such as T-cell depletion, have resulted in poor rates of engraftment. We have recently completed a phase II clinical trial of nonmyeloablative HLA-haploidentical hematopoietic BMT followed by post-transplantation high-cyclophosp...

2011-01-01

321

Strategies to optimize the outcome of children given T-cell depleted HLA-haploidentical hematopoietic stem cell transplantation  

British Library Electronic Table of Contents (United Kingdom)

The most advanced frontier of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is represented by the use of an HLA-partially matched relative as donor. In this type of transplantation, donor-derived natural killer (NK) cells, which are alloreactive towardtoward recipient cells, significantly contribute to the eradication of leukemia blasts. Alloreactive NK cells may also kill host dendritic cells and T lymphocytes, thus preventing graft-versus-host disease and graft rejection, respectively. Sophisticated strategies of adoptive infusion of T-cell lines/clones specific for the most life-threatening pathogens (namely cytomegalovirus, Epstein-Barr virus, Aspergillus and Adenovirus) have been envisaged, and successfully tested in a few pilot trials, to protect the recipient in the...

2011-01-01

322

Spatial ability and STEM: A sleeping giant for talent identification and development  

British Library Electronic Table of Contents (United Kingdom)

Spatial ability is a powerful systematic source of individual differences that has been neglected in complex learning and work settings; it has also been neglected in modeling the development of expertise and creative accomplishments. Nevertheless, over 50years of longitudinal research documents the important role that spatial ability plays in educational and occupational settings wherein sophisticated reasoning with figures, patterns, and shapes is essential. Given the contemporary push for developing STEM (science, technology, engineering, and mathematics) talent in the information age, an opportunity is available to highlight the psychological significance of spatial ability. Doing so is likely to inform research on aptitude-by-treatment interactions and Underwood's (1975) idea to utili...

2010-01-01

323

Short-term synaptic plasticity in the auditory brain stem by using in-vivo-like stimulation parameters  

British Library Electronic Table of Contents (United Kingdom)

Reduced systems such as brain slices offer a powerful approach to study the physiology of auditory neurons in great detail. However, when studying auditory nuclei in reduced systems such as brain slices, especially highly active auditory brain stem nuclei, one has to be aware that the unphysiological lack of activity in the reduced system compared to the in-vivo situation has a number of important effects on the neurons under investigation, and thus on the data that are measured. Most importantly, the lack of chronic activity in the slice preparation has important effects on the properties of short-term plasticity of the synapses. The main purpose of this article is to discuss how spontaneous activity in auditory neurons, or the lack thereof, can affect the data measured.

2011-01-01

324

Setting the standard in T-cell-depleted haploidentical transplantation and beyond  

British Library Electronic Table of Contents (United Kingdom)

Much progress has been made in the clinical, biological and technical aspects of the T-cell-depleted haploidentical hematopoietic stem cell transplantation (HSCT). Our experience demonstrates that infusing a megadose of extensively T-cell-depleted hematopoietic peripheral blood stem cells after an immuno-myeloablative conditioning regimen in acute leukemia patients ensures sustained engraftment with minimal GvHD without the need of any post-transplant immunosuppressive treatment. Since our first successful pilot study, our efforts have concentrated on developing new conditioning regimens, optimizing the graft processing and improving the post-transplant immunological recovery. The results we have so far achieved in high risk acute leukemia patients show that haploidentical transplantation ...

2011-01-01

325

Retracted:Effects of pro-inflammatory cytokines on mineralization potential of rat dental pulp stem cells  

British Library Electronic Table of Contents (United Kingdom)

Abstract The following article from the Journal of Tissue Engineering and Regenerative Medicine, -Effects of Pro-inflammatory Cytokines on Mineralization Potential of Rat Dental Pulp Stem Cells- by Yang X, Walboomers XF, Bian Z, Jansen JA, Fan M, published online on 11 July 2011 in Wiley Online Library (), has been retracted by agreement between the authors, the journal Editor-in-Chief, and John Wiley & Sons, Ltd. The retraction has been agreed due to two authors (Walboomers XF, and Jansen JA) not having been involved in the research described, nor made aware of their names being listed on the manuscript, nor told of its submission to the journal.

2011-01-01

326

Reproductive toxicologic evaluations of Bulbine natalensis Baker stem extract in albino rats  

British Library Electronic Table of Contents (United Kingdom)

The effects of oral administration of aqueous extract of Bulbine natalensis Baker stem at daily doses of 25, 50, and 100mg/kg body weight on the reproductive function of Wistar rats were evaluated. The indices of mating and fertility success as well as quantal frequency increased after 7 days of treatment in all the dose groups except the 100mg/kg body weight group. The number of litters was not statistically different (P>0.05) from the control. Whereas the absolute weights of the epididymis, seminal vesicle, and prostate were not affected, that of the testes was significantly increased. The epididymal sperm count, motility, morphology, and viscosity were not different from the control after 7 days of treatment. The male rat serum testosterone, progesterone, luteinizing hormone, and follic...

2009-01-01

327

Pretransplant Predictors and Posttransplant Sequels of Acute Kidney Injury after Allogeneic Stem Cell Transplantation  

British Library Electronic Table of Contents (United Kingdom)

Acute kidney injury (AKI) is a common complication after allogeneic stem cell transplantation (SCT). Although various risk factors for AKI have been reported, the influence of pretransplant comorbidity on the incidence of AKI has not been well investigated. We performed a retrospective analysis of 207 consecutive patients undergoing myeloablative or nonmyeloablative SCT between 2001 and 2009, using the hematopoietic cell transplantation-specific comorbidity index (HCT-CI) as a representative of pretransplant comorbidities. According to Risk, Injury, Failure, Loss, and End-stage kidney disease (RIFLE) criteria, 158 patients (76.3%) developed AKI, and 92 patients (44.4%) developed severe AKI (RIFLE class I or class F) within 100 days after SCT. The cumulative incidence of severe AKI within 1...

2011-01-01

328

Optimizing the conditioning regimen for allogeneic stem-cell transplantation in acute myeloid leukemia; dose intensity is still in need  

British Library Electronic Table of Contents (United Kingdom)

Allogeneic stem-cell transplantation (SCT) is potentially curative therapy in AML by providing both dose-intensive chemo-radiotherapy and induction of graft-versus-leukemia (GvL) effect. Historically, more emphasis was given to the intensity of conditioning. Over the last decade the pendulum turned more towards induction of GvL as the primary goal. A plethora of non-myeloablative (NMA) and reduced-intensity conditioning regimens (RIC) were introduced trying to reduce transplant-related toxicities and allow SCT in elderly and medically infirm patients. In addition, reduced-toxicity myeloablative regimens (RTC) based on fludarabine and myeloablative alkylating-agent doses were designed to allow safer administration of dose-intensive therapy. Conditioning dose-intensity is highly correlated w...

2011-01-01

329

Molecular pathology of tumor-initiating cells: Lessons from Philadelphia chromosome-positive leukemia  

British Library Electronic Table of Contents (United Kingdom)

Recent improvements in cell purification and transplantation techniques have contributed to the identification of cell populations known as tumor-initiating cells (TIC). This discovery has led to the -cancer stem cell hierarchy- concept, which holds that tumors are organized as a hierarchy of malignant tissues sustained by such TIC. However, this concept remains controversial. In this review, we examine recent advances in cancer stem cell research that have been generated from studies of Philadelphia (Ph) chromosome-positive leukemia. The abnormal Ph chromosome, which arises from a translocation creating the BCR-ABL1 fusion gene, is most commonly associated with chronic myelogenous leukemia (CML) and precursor B cell acute lymphoblastic leukemia (B-ALL). Examination of the pathophysiology ...

2011-01-01

330

Ionizing radiation is a potent inducer of mitotic recombination in mouse embryonic stem cells  

British Library Electronic Table of Contents (United Kingdom)

Maintenance of genomic integrity in embryonic cells is pivotal to proper embryogenesis, organogenesis and to the continuity of species. Cultured mouse embryonic stem cells (mESCs), a model for early embryonic cells, differ from cultured somatic cells in their capacity to remodel chromatin, in their repertoire of DNA repair enzymes, and in the regulation of cell cycle checkpoints. Using 129XC3HF1 mESCs heterozygous for Aprt, we characterized loss of Aprt heterozygosity after exposure to ionizing radiation. We report here that the frequency of loss of heterozygosity mutants in mESCs can be induced several hundred-fold by exposure to 5-10Gy of X-rays. This induction is 50-100-fold higher than the induction reported for mouse adult or embryonic fibroblasts. The primary mechanism underlying the...

2011-01-01

331

In vitro differentiation of rat embryonic stem cells into functional cardiomyocytes  

British Library Electronic Table of Contents (United Kingdom)

The recent breakthrough in the generation of rat embryonic stem cells (rESCs) opens the door to application of gene targeting to create models for the study of human diseases. In addition, the in vitro differentiation system from rESCs into derivatives of three germ layers will serve as a powerful tool and resource for the investigation of mammalian development, cell function, tissue repair, and drug discovery. However, these uses have been limited by the difficulty of in vitro differentiation. The aims of this study were to establish an in vitro differentiation system from rESCs and to investigate whether rESCs are capable of forming terminal-differentiated cardiomyocytes. Using newly established rESCs, we found that embryoid body (EB)-based method used in mouse ESC (mESC) differentiation...

2011-01-01

332

Importance of serum source for the in vitro replicative senescence of human bone marrow derived mesenchymal stem cells  

British Library Electronic Table of Contents (United Kingdom)

Abstract Human mesenchymal stem cells (hMSCs) may be used for therapeutic applications. Culture conditions such as the serum source may impact on cell quality and the onset of replicative senescence. We have examined the effect of culturing hMSCs in autologous serum (AS) versus fetal bovine serum (FBS) on factors involved in in vitro replicative senescence. hMSCs from four donors were cultured in 10% FBS or 10% AS until they reached senescence. Cells were harvested at early passage and near senescence to study factors known to be involved in cellular senescence. The number of population doublings till senescence was similar for cells cultured in FBS, but varied greatly for hMSCs cultured in AS. FBS cells accumulated in S phase of cell cycle. This could not be explained by increased express...

2011-01-01

333

Impact of Ecosystem Management on Microbial Community Level Physiological Profiles of Postmining Forest Rehabilitation  

British Library Electronic Table of Contents (United Kingdom)

We investigated the impacts of forest thinning, prescribed fire, and contour ripping on community level physiological profiles (CLPP) of the soil microbial population in postmining forest rehabilitation. We hypothesized that these management practices would affect CLPP via an influence on the quality and quantity of soil organic matter. The study site was an area of Jarrah (Eucalyptus marginata Donn ex Sm.) forest rehabilitation that had been mined for bauxite 12?years previously. Three replicate plots (20???20?m) were established in nontreated forest and in forest thinned from 3,000?8,000 stems ha?1 to 600?800 stems ha?1 in April (autumn) of 2003, followed either by a prescribed fire in September (spring) of 2003 or left nonburned. Soil samples were collected in August 2004 from two soil ...

2008-01-01

334

Immunoselection and clinical use of T regulatory cells in HLA-haploidentical stem cell transplantation  

British Library Electronic Table of Contents (United Kingdom)

Introduction: Haploidentical transplantation, with extensive T cell depletion to prevent GvHD, is associated with a high incidence of infection-related deaths. The key challenge is to improve immune recovery with allogeneic donor T cells without triggering GvHD. As T regulatory cells (Tregs) controlled GvHD in pre-clinical studies, the present study evaluated the impact of an infusion of donor CD4/CD25 + Tregs, followed by an inoculum of donor mature T cells (Tcons) and positively immunoselected CD34 + cells in the setting of haploidentical stem cell transplantation. Patients and methods: Twenty-eight patients were enrolled in this study (22 AML; 5 ALL; 1 NHL). All received immunoselected Tregs (CliniMACS, Miltenyi Biotec) followed by positively immunoselected CD34 + cells together with Tc...

2011-01-01

335

Gene Regulation of Extracellular Matrix Remodeling in Human Bone Marrow Stem Cell-Seeded Tissue-Engineered Grafts  

British Library Electronic Table of Contents (United Kingdom)

Tissue-engineered heart valves are prone to early structural deterioration. We hypothesize that cell?scaffold interaction and mechanical deformation results in upregulation of genes related to osteogenic/chondrogenic differentiation and thus changes extracellular matrix (ECM) composition in human bone marrow mesenchymal stem cell (hBMSC)-derived tissue-engineered grafts. hBMSC were expanded and seeded onto poly-glycolic acid/poly-lactic acid scaffold for 14 days. Seeded tissue-engineered constructs (TEC) were subjected to cyclic flexure for 24?h, whereas control TEC was maintained in roller bottles for the same duration. hBMSC, TEC, and mechanically deformed TEC were subjected to gene-array and histological analysis. Expression levels of RNA and/or protein markers related to chondrogenesis...

2011-01-01

336

Evaluation of carbon-14 (C{sup 14}) levels of terrestrial and marine food products of the environment of the site of Cogema La Hague; Evaluation des niveaux de carbone-14 ({sup 14}C) des denrees alimentaires terrestres et marines de l'environnement du site de COGEMA - La Hague  

Energy Technology Data Exchange (ETDEWEB)

This evaluation has for object to inform about the levels in carbon 14 in the environment of the factories of La Hague. Two sectors were differentiated on one hand the terrestrial environment, and on the other hand the marine environment. The investigations concerned first and foremost food products stemming as the vegetable culture (vegetables) or individual breeding (milk, eggs) but also foodstuffs stemming from the local agriculture (cereal). In touch with the second sector, the marine environment, the sampling concerned the accessible products of the sea by all and those locally marketed (fishes, molluscs, shellfishes). The different results are presented in tables. (N.C.)

2006-04-15

337

Comparison of fluorescence in situ hybridisation using peptide nucleic acid probes, Gram stain/acridine orange leukocyte cytospin and differential time to positivity methods for detection of catheter related bloodstream infection in patients after haematopoietic stem cell transplantation  

British Library Electronic Table of Contents (United Kingdom)

Abstract In 46 febrile neutropenic patients who had undergone haematopoietic stem cell transplantation, the fluorescence in situ hybridisation using peptide nucleic acid probes (PNA FISH), Gram stain/acridine orange leukocyte cytospin (Gram/AOLC), and differential time to positivity (DTP) methods were performed for detection of catheter related bloodstream infections (CRBSIs). As compared with the DTP method (which detected 11 patients with CRBSI), the PNA FISH and the Gram/AOLC methods detected ten of 11 CRBSI patients, resulting in a sensitivity, specificity, negative predictive value and positive predictive value of 91%, 100%, 97% and 100%, respectively, for the PNA FISH method as well as for the Gram/AOLC method.

2010-01-01

338

Chondrocytes and bone marrow-derived mesenchymal stem cells undergoing chondrogenesis in agarose hydrogels of solid and channelled architectures respond differentially to dynamic culture conditions  

British Library Electronic Table of Contents (United Kingdom)

Abstract The objective of this study was to investigate how a combination of different scaffold architectures and rotational culture would influence the functional properties of thick cartilaginous tissues engineered using either chondrocytes or bone marrow-derived mesenchymal stem cells (BM-MSCs). Expanded porcine chondrocytes and BM-MSCs were suspended in 2% agarose and cast in custom-designed moulds to produce either regular solid or channelled construct cylinders. The study consisted of three seperate experimental arms. First, chondrocyte and BM-MSC constructs were cultured in free swelling conditions for 9 weeks. Second, constructs were subjected to rotational culture for a period of 3 weeks. Finally, BM-MSC-seeded constructs were subjected to delayed rotational culture, in which cons...

2011-01-01

339

Biological scarcity: looking beyond regulatory exteriors in Taiwan  

British Library Electronic Table of Contents (United Kingdom)

Research and bioethical policies are increasingly seen to facilitate, rather than to impede, scientific progress. Bioethical structures, nonetheless, often fail to account for or to shape the specific social surrounds in which scientific research is conducted. In Taiwan, a perceived shortage in human biological donations threatens to hamper stem cell research progress. This paper considers the stalled national biobank project and the lack of a reliable embryo supply for stem cell research, and suggests that one must look beyond regulatory structures in seeking explanations for such shortages. Specific aspects of Taiwan's democratization and social changes combine with problematic relations between patients and physicians to shape the terrain upon which human biologicals are given or withhe...

2011-01-01

340

A novel BMT technique for treatment of various currently intractable diseases  

British Library Electronic Table of Contents (United Kingdom)

A recently-developed BMT method combines a ''Perfusion Method'' (PM) for collecting bone marrow cells (BMCs) with the Intra-Bone Marrow (IBM) injection of BMCs (IBM-BMT). As distinct from the conventional aspiration method (AM), the PM allows rapid (within 1 h) collection of BMCs without T cell contamination (T cells < 10%). Therefore, no GvHD occurs. Moreover, the burden on donors, such as back pain, bleeding and infection, can be reduced. Full chimerism can be achieved even with only mild conditioning regimens if IBM-BMT is carried out, since IBM-BMT replaces not only the recipient's hemopoietic stem cells (HSCs) but also mesenchymal stem cells (MSCs) with donor-derived HSCs and MSCs. Using this method, we show that most currently intractable diseases are HSC or MSC disorders, and that t...

2011-01-01

341

gtz_eco_dokument_cd-rom  

Wastenet

to have a long-term impact on continuous improvement and national economic growth .

342

Type I (RI) and type II (RII) receptors for transforming growth factor-beta isoforms are expressed subsequent to transforming growth factor-beta ligands during excisional wound repair.  

UK PubMed Central (United Kingdom)

Transforming growth factor (TGF)-beta isoforms (TGF-beta 1, -beta 2, and -beta 3) regulate cell growth and differentiation and have critical regulatory roles in the process of tissue repair and remodeling....Full Text Available

1997-01-01

355

Coupled Growth and Division of Model Protocell Membranes  

UK PubMed Central (United Kingdom)

The generation of synthetic forms of cellular life requires solutions...Full Text Available

2009-04-22

357

Detection of high-frequency radiation sources during the 2004 Parkfield earthquake by a matched filter analysis  

Science.gov (United States)

Introduction Uchide and Ide [SSA Spring Meeting, 2009] proposed a new framework for studying the scaling and overall nature of earthquake rupture growth in terms of cumulative moment functions. For better understanding of rupture growth processes, spatiotemporally local processes are also important. The nature of high-frequency (HF) radiation has been investigated for some time, but its role in the earthquake rupture process is still unclear. A wavelet analysis reveals that the HF radiation (e.g., 4 - 32 Hz) of the 2004 Parkfield earthquake is peaky, which implies that the sources of the HF radiation are isolated in space and time. We experiment with applying a matched filter analysis using small template events occurring near the target event rupture area to test whether it can reveal the HF radiation sources for a regular large earthquake. Method We design a matched filter for multiple components and stations. Shelly et al. [2007] attempted ...

2009-12-01

358

Heteroepitaxial growth of cubic boron nitride single crystal on diamond seed under high pressure  

International Nuclear Information System (INIS)

Single crystal cubic boron nitride (cBN) was heteroepitaxially grown on a seed crystal of diamond under static high pressure and high temperature at 5.5GPa and 1,600--1,700 C, respectively, for 10--100 hour. A temperature gradient method was employed for the crystal growth by using lithium boron nitride as a solvent. Initial growth feature of cBN crystal was found on the diamond seed surface after the growing time of 10 minutes. The nucleation sites of the crystals seem to be near the etch pits on the diamond surface which were introduced by the surface dissolution by the solvent for cBN growth. Two types of growth features, island and step growth were typically shown on the surface. It can be seen that grown crystal appearing as a (111) nitrogen face was exhibited with the step growth feature, while the (11n) face exhibited the island ...

1997-04-04

359

Breaking the Biological barriers to Cellulosic Ethanol: A Joint Research Agenda  

Energy Technology Data Exchange (ETDEWEB)

A robust fusion of the agricultural, industrial biotechnology, and energy industries can create a new strategic national capability for energy independence and climate protection. In his State of the Union Address (Bush 2006), President George W. Bush outlined the Advanced Energy Initiative, which seeks to reduce our national dependence on imported oil by accelerating the development of domestic, renewable alternatives to gasoline and diesel fuels. The president has set a national goal of developing cleaner, cheaper, and more reliable alternative energy sources to substantially replace oil imports in the coming years. Fuels derived from cellulosic biomass - the fibrous, woody, and generally inedible portions of plant matter - offer one such alternative to conventional energy sources that can dramatically impact national economic growth, national energy security, and environmental goals. Cellulosic biomass is an attractive energy feedstock ...

2006-06-01

360

Transfer of uranium and thorium from soil to different parts of medicinal plants using SSNTD  

International Nuclear Information System (INIS)

The uptake of "2"3"8U and "2"3"2Th in different parts of some selected plants used in traditional treatment of hypertension and diabetes in south-eastern Morocco (Errachidia area) has been studied using two different types of solid state nuclear track detectors (SSNTDs) LR-115 type II and CR-39. Plant uptake of radionuclides is one of many vectors for introduction of contaminants into the human food chain. Thus, it is critical to understand soil-plant relationships that control nuclide bioavailability. Soil concentrations of uranium ranged from 6.10 to 11.62 ppm, with a mean of 7.90 ppm. Soil concentrations of thorium ranged from 2.70 to 4.80 ppm, with a mean of 3.41 ppm. Mean uranium specific activities were 8.38 Bq kg"-"1 in root tissue, 5 Bq kg"-"1 in stem tissue and 6.02 Bq kg"-"1 in leaf tissue. Mean thorium specific activities were 2.53 Bq kg"-"1 in root tissue, 1.64 Bq kg"-"1 in stem tissue and 1.96 Bq kg"-"1 in leaf tissue. The transfer ...

2011-02-01

361

Tissue culture process for the clonal production of loblolly pine plantlets  

Energy Technology Data Exchange (ETDEWEB)

A tissue culture process, organogenesis, is described which involves the stepwise production of a shoot apex, which grows to have leaves and stem and finally roots, culminating in the production of a complete plant. The production and subsequent development of numerous adventitious shoots, preferably from adult tree tissues offers the greatest potential for commercial cloned plantlet production. The process describes these steps for Pinus taeda, the loblolly pine. (Refs. 25).

1981-02-01

362

The hyperon neutron star mean-field model  

Energy Technology Data Exchange (ETDEWEB)

The properties of strange neutron stars have been studied with the use of the parameter sets stemming from the effective field theory. The impact of the strength of hyperon interactions on neutron star masses has been analyzed. The inclusion of additional nonlinear meson interaction terms together with the strong hyperon-hyperon interaction leads to the existence of additional stable stellar configurations. (authors)

2007-05-15

363

Primitive hematopoietic cells resist HIV-1 infection via p21Waf1/Cip1/Sdi1  

UK PubMed Central (United Kingdom)

Hematopoietic stem cells are resistant to HIV-1 infection. Here, we report a novel mechanism by which the cyclin-dependent kinase inhibitor (CKI) p21Waf1/Cip1/Sdi1 (p21), a known regulator...Full Text Available

2007-02-01

364

PET and MR imaging in a neuro-Behcet syndrome  

Energy Technology Data Exchange (ETDEWEB)

Positron emission tomography (PET) and magnetic resonance imaging (MRI) studies were performed on a case of neuro-Behcet's syndrome. In accordance with the clinical signs, FDG PET (using /sup 18/F-labeled 2-F-2'-desoxyglucose) revealed disseminated storage defects in the cerebrum and cerebellum. Focal regions of enhanced signal intensity were demonstrated in the parietal white matter of the cerebrum in T2-weighted images and in the brain stem by MRI. (orig.).

1989-11-01

365

Niobium superconducting cavity  

CERN Multimedia

This 5-cell superconducting cavity, made from bulk-Nb, stems from the period of general studies, not all directed towards direct use at LEP. This one is dimensioned for 1.5 GHz, the frequency used at CEBAF and also studied at Saclay (LEP RF was 352.2 MHz). See also 7908227, 8007354, 8209255, 8210054, 8312339.

1980-01-01

366

Insect-Induced Conifer Defense. White Pine Weevil and Methyl Jasmonate Induce Traumatic Resinosis, de Novo Formed Volatile Emissions, and Accumulation of Terpenoid Synthase and Putative Octadecanoid Pathway Transcripts in Sitka Spruce1[w  

UK PubMed Central (United Kingdom)

Stem-boring insects and methyl jasmonate (MeJA) are thought to induce similar complex chemical and anatomical defenses in conifers. To compare insect- and MeJA-induced terpenoid responses, we analyzed...Full Text Available

2005-01-01

367

Explore - The Lab - Australian Broadcasting Corporation's Gateway to Science  

Wastenet

...Explore - The Lab - Australian Broadcasting Corporation's Gateway to Science Radio TV Shop News Sport Local Children Science Environment more Topics help Science Home News in Science Features Explore TV & Radio Dr Karl Play Podcasts DNA - The discovery of the double helix structure of DNA completely changed biology and opened up the new field of genetics. The 'backbone of life' has given us the human genome, stem cell research, ...

368

Comparison of the genetic effects of equimolar doses of ENU and MNU: While the chemicals differ dramatically in their mutagenicity in stem-cell spermatogonia, both elicit very high mutation rates in differentiating spermatogonia  

UK PubMed Central (United Kingdom)

Mutagenic, reproductive, and toxicity effects of two closely related chemicals, ethylnitrosourea (ENU) and methylnitrosourea (MNU), were compared at equimolar and near-equimolar doses in the...Full Text Available

2007-03-01

369

Life evaluation of insulating materials for electric cable by accelerated thermal-radiation combined aging  

Energy Technology Data Exchange (ETDEWEB)

Radiation-and-thermal-combined degradation of ethylene-propylene rubber (EP rubber) and chlorosulfonated polyethylene (CSM) as cable insulating and jacketing materials were evaluated by accelerated aging tests and a method to assess the lifetime of these materials under practical application was studied. EP rubber and CSM of experimental formulation were degraded at accelerated rates, that are 50 [approx] 1000 times the degradation rate under a standard condition (1Gy/h, 50degC). The degradation was investigated by measuring the tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for both EP rubber and CSM were in proportion to increase in accelerated rate. Behaviors of elongation changes showed little difference with accelerated rate. EP rubber lifetime estimated from sequential aging test had a tendency to extend beyond that from ...

1992-10-01

370

Life evaluation of insulating materials for electric cable by accelerated thermal-radiation combined aging  

International Nuclear Information System (INIS)

Radiation-and-thermal-combined degradation of ethylene-propylene rubber (EP rubber) and chlorosulfonated polyethylene (CSM) as cable insulating and jacketing materials were evaluated by accelerated aging tests and a method to assess the lifetime of these materials under practical application was studied. EP rubber and CSM of experimental formulation were degraded at accelerated rates, that are 50 #approx# 1000 times the degradation rate under a standard condition (1Gy/h, 50degC). The degradation was investigated by measuring the tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for both EP rubber and CSM were in proportion to increase in accelerated rate. Behaviors of elongation changes showed little difference with accelerated rate. EP rubber lifetime estimated from sequential aging test had a tendency to extend beyond that from ...

1992-01-01

371

Future Accelerators, Muon Colliders, and Neutrino Factories  

Energy Technology Data Exchange (ETDEWEB)

Particle physics is driven by five great topics. Neutrino oscillations and masses are now at the fore. The standard model with extensions to supersymmetry and a Higgs to generate mass explains much of the field. The origins of CP violation are not understood. The possibility of extra dimensions has raised tantalizing new questions. A fifth topic lurking in the background is the possibility of something totally different. Many of the questions raised by these topics require powerful new accelerators. It is not an overstatement to say that for some of the issues, the accelerator is almost the experiment. Indeed some of the questions require machines beyond our present capability. As this volume attests, there are parts of the particle physics program that have been significantly advanced without the use of accelerators such as the subject of neutrino oscillations and many aspects of the particle-cosmology interface. At this ...

2001-12-19

372

Effect of gasoline octane quality on vehicle acceleration performance  

Energy Technology Data Exchange (ETDEWEB)

A study was conducted under the auspices of the Coordinating Research Council, Inc. (CRC) to assess the potential effects of gasoline octane quality on vehicle acceleration performance. Twelve participating laboratories, representing both the oil and the automotive industries, tested a total of 182 vehicles as part of the 1989 CRC Octane Number Requirement Survey. The vehicles consisted of 78 with electronic knock control systems and 104 without. All testing was performed using the 1989/1990 CRC FBRU fuel series. The results showed that acceleration performance of vehicles with knock sensors was significantly affected by gasoline octane quality. Octane effects on acceleration performance were most pronounced at maximum-throttle (detent) conditions and at octane levels below the vehicles' octane requirements; however, some knock-sensor vehicles did show improved acceleration performance with ...

1991-07-01

373

Review of ion accelerators  

Energy Technology Data Exchange (ETDEWEB)

The field of ion acceleration to higher energies has grown rapidly in the last years. Many new facilities as well as substantial upgrades of existing facilities have extended the mass and energy range of available beams. Perhaps more significant for the long-term development of the field has been the expansion in the applications of these beams, and the building of facilities dedicated to areas outside of nuclear physics. This review will cover many of these new developments. Emphasis will be placed on accelerators with final energies above 50 MeV/amu. Facilities such as superconducting cyclotrons and storage rings are adequately covered in other review papers, and so will not be covered here.

1990-06-01

374

Hydrogen flame acceleration and transition to detonation  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the results obtained from two large experimental facilities built at Sandia National Laboratories in Albuquerque, NM. FLAME (Flame Acceleration Measurements and Experiments) is a large horizontal rectangular channel designed to study flame acceleration, transition to detonation, simulation of combustion in containment geometries, component heating, and other problems in hydrogen combustion relevant to reactor safety. The Heated Detonation Tube has been designed to study detonations in hydrogen-air-steam mixtures. Both facilities have been in operation for just over a year. 12 figures.

1984-01-01

375

Hydrogen flame acceleration and transition to detonation  

International Nuclear Information System (INIS)

This paper describes the results obtained from two large experimental facilities built at Sandia National Laboratories in Albuquerque, NM. FLAME (Flame Acceleration Measurements and Experiments) is a large horizontal rectangular channel designed to study flame acceleration, transition to detonation, simulation of combustion in containment geometries, component heating, and other problems in hydrogen combustion relevant to reactor safety. The Heated Detonation Tube has been designed to study detonations in hydrogen-air-steam mixtures. Both facilities have been in operation for just over a year. 12 figures.

1984-10-23

376

Collective ion acceleration by a reflexing electron beam: model and scaling. Memorandum report  

Energy Technology Data Exchange (ETDEWEB)

Analytical and numerical calculations are presented for a reflexing electron beam type of collective ion accelerator. These results are then compared to those obtained through experiment. By constraining one free parameter to experimental conditions, the self-similar solution of the ion energy distribution agrees closely with the experimental distribution. Hence the reflexing beam model appears to be a valid model for explaining the experimental data. Simulation shows in addition to the agreement with the experimental ion distribution that synchronization between accelerated ions and electric field is phase unstable. This instability seems to further restrict the maximum ion energy to several times the electron energy.

1984-05-11

377

An efficient higher order family of root finders  

British Library Electronic Table of Contents (United Kingdom)

A one parameter family of iterative methods for the simultaneous approximation of simple complex zeros of a polynomial, based on a cubically convergent Hansen-Patricks family, is studied. We show that the convergence of the basic family of the fourth order can be increased to five and six using Newtons and Halleys corrections, respectively. Since these corrections use the already calculated values, the computational efficiency of the accelerated methods is significantly increased. Further acceleration is achieved by applying the Gauss-Seidel approach (single-step mode). One of the most important problems in solving nonlinear equations, the construction of initial conditions which provide both the guaranteed and fast convergence, is considered for the proposed accelerated family. These cond...

2008-01-01

378

Why the US should spend billions on a new particle accelerator  

CERN Multimedia

"The US must develop a compelling bid to host the International Linear Collider in order to safeguard American science." (1,5 page)

2006-01-01

379

VOLUME I! - NASA Technical Report Server (NTRS)  

Science.gov (United States)

and propels the projectile to a velocity sufficient to reach ..... CLF3 + N2 4 .... 5 inches or greater accelerates a finned projectile to the veloc ...

380

Twenty Years of Tevatron Operation  

Energy Technology Data Exchange (ETDEWEB)

The superconducting Tevatron accelerator at Fermi National Accelerator Laboratory (Fermilab) has surpassed twenty years of operation. The Tevatron is still the highest energy particle accelerator in the world and will remain so until the commissioning of the LHC in Europe later this decade. The Tevatron has operated in a Fixed Target mode, accelerating a proton beam into stationary targets/detectors, as well as a Colliding Beam mode, continuously colliding counter rotating beams of protons and antiprotons. Upon completion, the Tevatron cryogenic system became the world's largest helium refrigeration system. In 1993, the Tevatron cryogenic system was given the designation of International Historic Mechanical Engineering Landmark by the American Society of Mechanical Engineers. The operational history, experiences and statistics of the Tevatron, with an emphasis on the cryogenic system, is ...

2004-07-15

381

Spontaneous excitation of an accelerated atom in a spacetime with a reflecting plane boundary  

Science.gov (United States)

We study a two-level atom in interaction with a real massless scalar quantum field in a spacetime with a reflecting boundary. The presence of the boundary modifies the quantum fluctuations of the scalar field, which in turn modifies the radiative properties of atoms. We calculate the rate of change of the mean atomic energy of the atom for both inertial motion and uniform acceleration. It is found that the modifications induced by the presence of a boundary make the spontaneous radiation rate of an excited inertial atom oscillate near the boundary and this oscillatory behavior may offer a possible opportunity for experimental tests for geometrical (boundary) effects in flat spacetime. While for accelerated atoms, the transitions from ground states to excited states are found to be possible even in a vacuum due to changes in the vacuum fluctuations induced by both the presence of the boundary and the acceleration of atoms, ...

2005-09-15

382

Optimization for Vibration Isolation.  

Science.gov (United States)

An almost linear optimization problem of importance in vibration isolation has been identified and algorithms were developed to minimize the forced vibrational response of structural systems. The constraints can be either displacements of accelerations. T...

1983-01-01

383

Open-source software accelerates bioinformatics  

UK PubMed Central (United Kingdom)

A report on the Wellcome Trust/Cold Spring Harbor Genome Informatics meeting, Cold Spring Harbor, USA, 7-11 May 2003.

2003-01-01

385

Free-electron laser driven by the LBNL laser-plasma accelerator  

Energy Technology Data Exchange (ETDEWEB)

A design of a compact free-electron laser (FEL), generating ultra-fast, high-peak flux, XUV pulses is presented. The FEL is driven by ahigh-current, 0.5 GeV electron beam from the Lawrence Berkeley National Laboratory (LBNL) laser-plasma accelerator, whose active acceleration length is only a few centimeters. The proposed ultra-fast source (~;;10 fs) would be intrinsically temporally synchronized to the drive laser pulse, enabling pump-probe studies in ultra-fast science. Owing to the high current (>10 kA) of the laser-plasma-accelerated electron beams, saturated output fluxes are potentially greater than 10^13 photons/pulse. Devices based both on self-amplified spontaneous emission and high-harmonic generated input seeds, to reduce undulator length and fluctuations, are considered.

2008-08-04

386

Fast Beam Intensity Measurements for the LHC  

CERN Document Server

Particle accelerators are constructed and operated for a wide variety of applications. In particle physics - the branch of physics that studies the elementary constituents of matter and forces between them - high energy accelerators are used to look deep into the structure of matter. Medical particle accelerators are used for example in medicine to treat tumours [31], in imaging techniques such as Positron Emission Tomography (PET) [24], or for the radio-isotopes production. They also serve in many other industrial branches, e.g. geology, radiocarbon dating [39], molecular complex spectroscopy, lithography, food preservation etc. The eld of accelerator technology draws knowledge and expertise from a wide range of scientic disciplines and uses the latest technical knowledge. The incomplete list of covered disciplines includes mathematics, physics, electronics, computing, electromagnetic eld technology, ...

2010-01-01

387

Electromagnetic forming - a potentially viable technique for accelerator technology  

International Nuclear Information System (INIS)

Modern day accelerator development encompasses a myriad technologies required for their diverse needs. Whereas RF, high voltage, vacuum, cryogenics etc., technologies meet their functional requirements, high finish lapping processes, ceramic-metal joining, oven brazing, spark erosion or wire cutting etc., are a must to meet their fabrication requirements. Electromagnetic (EM) forming technique falls in the latter category and is developed as a special technology. It is currently catering to the development as a nuclear reactor technology, but has the potential to meet accelerator requirements too. This paper highlights the general principle of its working, simple design guidelines, advantages, and suggests some specific areas where this could benefit accelerator technologies

2003-02-03

388

ELECTROMAGNETIC AND THERMAL SIMULATIONS FOR THE SWITCH REGION OF A COMPACT PROTON ACCELERATOR  

Energy Technology Data Exchange (ETDEWEB)

A compact proton accelerator for medical applications is being developed at Lawrence Livermore National Laboratory. The accelerator architecture is based on the dielectric wall accelerator (DWA) concept. One critical area to consider is the switch region. Electric field simulations and thermal calculations of the switch area were performed to help determine the operating limits of rmed SiC switches. Different geometries were considered for the field simulation including the shape of the thin Indium solder meniscus between the electrodes and SiC. Electric field simulations were also utilized to demonstrate how the field stress could be reduced. Both transient and steady steady-state thermal simulations were analyzed to find the average power capability of the switches.

2007-06-15

389

Development of mini-LIA and primary experiments  

International Nuclear Information System (INIS)

Mini-LIA is a miniature of a linear induction accelerator developed by China Academy of Engineering Physics and Tsinghua University in 2007. It has been constructed with a thermionic cathode in an electron injector and a metglas core in the induction accelerator cavities. A double-pulsed electron beam was produced for the first time in China on the Mini-LIA with a thermionic cathode in the electron gun and a metglas core in the induction accelerator cavities. A double-pulsed beam current of more than 1.1A was obtained on condition of 80 kV double-pulsed high voltage produced by pulsed power system supplying to the injector and accelerating modules. Some primary experiments for measuring the parameters of Mini-LIA has been performed, and some beam characterizations of Mini-LIA are presented. Further improvement is underway. (authors)

2009-09-01

390

Deforestation in the Tropics  

Science.gov (United States)

Government policies that encourage exploitation--in particular excessive logging and clearing for ranches and farms--are largely to blame for the accelerating destruction of tropical forests. This paper surveys the problem in detail and briefly recommends potential solutions.

1990-04-01

391

Control of linear accelerator noise in the Los Alamos free-electron laser (FEL)  

International Nuclear Information System (INIS)

FELs require tight control of the amplitudes and phase of the fields in two linear accelerator tanks to obtain stable lasing. The accelerator control loops must establish constant, stable, repeatable amplitudes and phases of the rf fields and must have excellent bandwidth to control high-frequency noise components. A model of the feedback loops has been developed that agrees well with measurements and allows easy substitution of components and circuits, thus reducing breadboarding requirements. The model permits both frequency and time-domain analysis. The accelerator control scheme and model are described and the control of noise in feedback loops is discussed, showing how low-frequency-noise components (errors) can be corrected, but high-frequency-noise components (errors) are actually amplified by the feedback circuit. Measurements of noise in both open- and closed-loop modes is shown and comparison is made with results ...

1986-09-01

392

CERN scientists confront data deluge  

CERN Multimedia

The next generation of particle accelerator is currently being designed at CERN. An understanding of the market forces in the computer industry will play a crucial role in the success of the project.

1998-01-01

393

BC  

Wastenet

added to provide resistance to UV degradation, and vulcanization control. ...Sulphur is used to vulcanize the rubber ...additives and solvents age resistors, processing aids, accelerators, vulcanizing agents, softeners and fillers

394

Applied geodesy  

Energy Technology Data Exchange (ETDEWEB)

This volume is based on the proceedings of the CERN Accelerator School's course on Applied Geodesy for Particle Accelerators held in April 1986. The purpose was to record and disseminate the knowledge gained in recent years on the geodesy of accelerators and other large systems. The latest methods for positioning equipment to sub-millimetric accuracy in deep underground tunnels several tens of kilometers long are described, as well as such sophisticated techniques as the Navstar Global Positioning System and the Terrameter. Automation of better known instruments such as the gyroscope and Distinvar is also treated along with the highly evolved treatment of components in a modern accelerator. Use of the methods described can be of great benefit in many areas of research and industrial geodesy such as surveying, nautical and aeronautical engineering, astronomical radio-interferometry, metrology of ...

1987-01-01

395

An Advance in Superconducting Magnet Technology Opens the Door...  

Science.gov (United States)

magnet research at several national laboratories through its Advanced Accelerator Technology Program. The HEP Conductor Development Program, a collaboration among national...

2011-08-20

396

Accelerator-based analytical techniques using ion and photon beams. Environmental and industrial applications  

International Nuclear Information System (INIS)

An overview of different Ion Beam Analysis (IBA) techniques is given. Examples of applications of the PIXE techniques to various types of samples are presented. (author)

1999-11-01

397

Scale prevention with special reference to threshold treatment  

Energy Technology Data Exchange (ETDEWEB)

Various chemical, physical, and mechanical methods to prevent unwanted deposition of mineral scale are described. The suitability of the different methods, which largely depends on the specific features and requirements of the system involved, is discussed. Special emphasis is placed upon the threshold treatment, where the growth process is retarded by the addition of trace amounts of growth inhibitors. Growth experiments have been performed on barium sulfate and calcium sulfate dihydrate seed crystals, suspended in a supersaturated solution with and without organic bisphosphonates as inhibitors. Two methods are selected for the analysis of the growth data. A degree of inhibition is defined to obtain a quantitative description of the influence of a growth inhibitor on the growth rate of the crystals. In addition the influence of the molecular structure of ...

1983-01-01

398

Effects of size and spacing of uniformly distributed pearlite particles on fatigue crack growth behavior of ferrite pearlite steels  

British Library Electronic Table of Contents (United Kingdom)

Fatigue crack growth tests of three ferrite-pearlite steels with different size and spacing of pearlite particles, which were uniformly distributed in the ferrite matrix, were carried out to investigate the effect of microstructure on fatigue crack growth behavior in the Paris regime. The fatigue crack growth rates for the three materials did not coincide with each other, even when the crack growth curves were arranged by the effective stress intensity factor range. From in situ observations, crack tip stress shielding phenomena, such as interlocking and branching, were found on the crack wake, which enhanced fatigue crack growth resistance. A small size and spacing of pearlite particle seemed to induce small but frequent crack deflections, which resulted in crack closure phenomena. On the...

2010-01-01

399

Transforming growth factor-?1 induces intestinal myofibroblast differentiation and modulates their migration  

UK PubMed Central (United Kingdom)

AIM: To investigate the effects of transforming growth factor β1 (TGF-β1) on the differentiation of colonic lamina propria fibroblasts (CLPF) into myofibroblasts in vitro.METHODS:...Full Text Available

2009-03-28

400

Trade-offs Between Seedling Growth and Survival in Deciduous Broadleaved Trees in a Temperate Forest  

UK PubMed Central (United Kingdom)

Background and AimsIn spatially heterogeneous environments, a trade-off between seedling survival and relative growth rate may promote the coexistence of plant species. In temperate...Full Text Available

2007-03-01

401

The Role of Placental Homeobox Genes in Human Fetal Growth Restriction  

UK PubMed Central (United Kingdom)

Fetal growth restriction (FGR) is an adverse pregnancy outcome associated with significant perinatal and paediatric morbidity and mortality, and an increased risk of chronic disease later in adult life....Full Text Available

2011-01-01

402

The Notochord, Notochordal cell and CTGF/CCN-2: ongoing activity from development through maturation  

UK PubMed Central (United Kingdom)

The growth regulating factor CTGF/CCN-2 is an integral factor in growth and development, connective tissue maintenance, wound repair and cell cycle regulation. It has recently been reported that CTGF/CCN-2...Full Text Available

2008-12-01

403

The Mammalian Neuroendocrine Hormone Norepinephrine Supplies Iron for Bacterial Growth in the Presence of Transferrin or Lactoferrin  

UK PubMed Central (United Kingdom)

Norepinephrine stimulates the growth of a range of bacterial species in nutritionally poor SAPI minimal salts medium containing 30% serum. Addition of size-fractionated serum components to SAPI...Full Text Available

2000-11-01

404

The Long-Term Effects of Prematurity and Intrauterine Growth Restriction on Cardiovascular, Renal, and Metabolic Function  

UK PubMed Central (United Kingdom)

Objective. To determine relative influences of intrauterine growth restriction (IUGR) and preterm birth on risks of cardiovascular, renal, or metabolic dysfunction in adolescent...Full Text Available

2010-01-01

405

The Hippo tumor-suppressor pathway regulates apical-domain size in parallel to tissue growth  

UK PubMed Central (United Kingdom)

SummaryThe Hippo tumor-suppressor pathway controls tissue growth in Drosophila and mammals by regulating cell proliferation and apoptosis. The Hippo pathway includes...Full Text Available

2009-07-15

406

The Effect of O2, H2O, and N2 on the Fatigue Crack Growth Behavior of an Alpha + Beta Titanium Alloy at 24 C and 177 C  

Science.gov (United States)

To study the effects of atmospheric species on the fatigue crack growth behavior of an a+B titanium

2001-01-01

407

T cell-engaging BiTE antibodies specific for EGFR potently eliminate KRAS- and BRAF-mutated colorectal cancer cells  

UK PubMed Central (United Kingdom)

Epidermal growth factor receptor (EGFR)-specific monoclonal antibodies predominantly inhibit colorectal cancer (CRC) growth by interfering with receptor signaling. Recent analyses have shown that patients...Full Text Available

2010-07-13

408

Structural basis of growth-related gain and age-related loss of bone strength  

UK PubMed Central (United Kingdom)

If bone strength was the only requirement of skeleton, it could be achieved with bulk, but bone must also be light. During growth, bone modelling and remodelling optimize strength, by depositing bone...Full Text Available

2008-07-01

409

Staphylococcus aureus Aconitase Inactivation Unexpectedly Inhibits Post-Exponential-Phase Growth and Enhances Stationary-Phase Survival  

UK PubMed Central (United Kingdom)

Staphylococcus aureus preferentially catabolizes glucose, generating pyruvate, which is subsequently oxidized to acetate under aerobic growth conditions. Catabolite repression of the...Full Text Available

2002-11-01

410

Sonic hedgehog controls growth of external genitalia by regulating cell cycle kinetics  

UK PubMed Central (United Kingdom)

During embryonic development, cells are instructed which position to occupy, they interpret these cues as differentiation programmes, and expand these patterns by growth. Sonic hedgehog...Full Text Available

2010-06-01

411

Sexual maturity in growing dinosaurs does not fit reptilian growth models  

UK PubMed Central (United Kingdom)

Recent histological studies suggest relatively rapid growth in dinosaurs. However, the timing of reproductive maturity (RM) in dinosaurs is poorly known because unambiguous indicators of RM are rare....Full Text Available

2008-01-15

412

SH2-B Is Required for Both Male and Female Reproduction  

UK PubMed Central (United Kingdom)

Many growth factors and hormones modulate the reproductive status in mammals. Among these, insulin and insulin-like growth factor I (IGF-I) regulate the development of gonadal tissues. SH2-B has been...Full Text Available

2002-05-01

413

Rapid detection of epidermal growth factor receptor mutations with multiplex PCR and primer extension in lung cancer  

UK PubMed Central (United Kingdom)

Epidermal growth factor receptor (EGFR) kinase domain mutations hyperactivate the kinase and confer kinase addiction of the non-small-cell lung cancer (NSCLC) tumor...Full Text Available

414

Quantitative Analysis of Endocytosis and Turnover of Epidermal Growth Factor (EGF) and EGF Receptor  

UK PubMed Central (United Kingdom)

Binding of epidermal growth factor (EGF) to the EGF receptor (EGFR) initiates signal transduction, ultimately leading to altered gene expression. Ligand-activated EGFR is also rapidly internalized...Full Text Available

2010-03-01

415

Promotive Effect of Minoxidil Combined with All-trans Retinoic Acid (tretinoin) on Human Hair Growth in Vitro  

UK PubMed Central (United Kingdom)

Minoxidil induces hair growth in male pattern baldness and prolongs the anagen phase. All-trans retinoic acid (ATRA) has been reported to act synergistically with minoxidil in vivo:...Full Text Available

2007-04-01

416

Preparation of internally labelled rat pituitary somatotropin (growth hormone).  

UK PubMed Central (United Kingdom)

Rat somatotropin (growth hormone) was labelled biosynthetically by incubating anterior pituitary lobes with radioactive amino acids for 24 h in a simple buffered salts medium containing glucose. The...Full Text Available

1978-03-01

417

Predictive and prognostic markers for epidermal growth factor receptor inhibitor therapy in non-small cell lung cancer  

UK PubMed Central (United Kingdom)

Epidermal growth factor receptor (EGFR) related therapies – mainly tyrosine kinase inhibitors (TKIs) such as erlotinib and gefitinib, but also monoclonal antibodies targeting EGFR, for example,...Full Text Available

2009-11-01

418

Posttraumatic growth, posttraumatic stress disorder and resilience of motor vehicle accident survivors  

UK PubMed Central (United Kingdom)

BackgroundAlthough some previous studies have suggested that posttraumatic growth (PTG) is comprised of several factors with different properties, few have examined both the association...Full Text Available

419

Polymorphisms in the epidermal growth factor receptor gene and the risk of primary lung cancer: a case-control study  

UK PubMed Central (United Kingdom)

BackgroundPolymorphisms in Epidermal Growth Factor Receptor (EGFR) gene may influence EGFR production and/or activity, thereby modulating susceptibility to lung...Full Text Available

420

Platelet-derived growth factor inhibits bone regeneration induced by osteogenin, a bone morphogenetic protein, in rat craniotomy defects.  

UK PubMed Central (United Kingdom)

Platelet-derived growth factor (PDGF) is a potent moderator of soft tissue repair through induction of the inflammatory phase of repair and subsequent enhanced collagen deposition. We examined the effect...Full Text Available

1993-12-01

421

Name of Presentation!  

Wastenet

Up-flow anaerobic attached-growth bioreactors filled with pre-treated coir fibres ...coir-fibre arranged in bottle-brush configuration bounded by a novel plastic binding technique ...-three anaerobic filter reactors in series -coir fibre as the bacteria growth media a sedimentation

422

Insulin-Like Growth Factor I Receptor Signaling Is Required for Exercise-Induced Cardiac Hypertrophy  

UK PubMed Central (United Kingdom)

The receptors for IGF-I (IGF-IR) and insulin (IR) have been implicated in physiological cardiac growth, but it is unknown whether IGF-IR or IR signaling are critically required. We generated mice with...Full Text Available

2008-11-01

423

Insect growth regulators and insect control: a critical appraisal.  

UK PubMed Central (United Kingdom)

Insect growth regulators (IGRs) of the juvenile hormone type alter physiological processes essential to insect development and appear to act specifically on insects. Three natural juvenile hormones...Full Text Available

1976-04-01

424

Improved airway healing using basic fibroblast growth factor in a canine tracheal autotransplantation model.  

UK PubMed Central (United Kingdom)

OBJECTIVE: We studied 22 dogs to examine the effect of basic fibroblast growth factor (bFGF) alone, in comparison with omental or muscular wrapping on airway healing in a tracheal autotransplantation...Full Text Available

1998-03-01

425

Growth-Phase-Dependent Expression of Virulence Factors in an M1T1 Clinical Isolate of Streptococcus pyogenes  

UK PubMed Central (United Kingdom)

The effect of growth phase on expression of virulence-associated factors was studied by Northern hybridization in an M1T1 clinical isolate of Streptococcus pyogenes. Expression of M...Full Text Available

1999-10-01

426

Growth, cell division and sporulation in mycobacteria  

UK PubMed Central (United Kingdom)

Bacteria have the ability to adapt to different growth conditions and to survive in various environments. They have also the capacity to enter into dormant states and some bacteria form spores when...Full Text Available

2010-08-01

427

Growth and Energy Generation by Lactococcus lactis subsp. lactis biovar diacetylactis during Citrate Metabolism  

UK PubMed Central (United Kingdom)

Growth of Lactococcus lactis subsp. lactis biovar diacetylactis was observed on media with citrate as the only energy source. At pH 5.6, steady state was achieved in...Full Text Available

1993-12-01

428

Factors affecting the aggregation of Actinomyces naeslundii during growth and in washed cell suspensions.  

UK PubMed Central (United Kingdom)

Various factors affecting the aggregation of Actinomyces naeslundii strain 12104 were studied. When the pH of glucose-supplemented growth medium fell below 5.5, the cells aggregated and formed microbial...Full Text Available

1978-09-01

429

Exploring posttraumatic growth in children impacted by Hurricane Katrina: Correlates of the phenomenon and developmental considerations  

UK PubMed Central (United Kingdom)

This study explored posttraumatic growth (PTG), positive change resulting from struggling with trauma, among 7- to 10-year-olds impacted by Hurricane Katrina. Analyses focused on child self-system...Full Text Available

2010-07-01

430

Estrogen and brain-derived neurotrophic factor (BDNF) in hippocampus: complexity of steroid hormone-growth factor interactions in the adult CNS.  

UK PubMed Central (United Kingdom)

In the CNS, there are widespread and diverse interactions between growth factors and estrogen. Here we examine the interactions of estrogen and brain-derived neurotrophic factor (BDNF), two...Full Text Available

2006-12-01

431

Effects of a growth hormone-releasing hormone antagonist on telomerase activity, oxidative stress, longevity, and aging in mice  

UK PubMed Central (United Kingdom)

Both deficiency and excess of growth hormone (GH) are associated with increased mortality and morbidity. GH replacement in otherwise healthy subjects leads to complications, whereas individuals with...Full Text Available

2010-12-21

432

Effect of a Longitudinally Applied Voltage Upon the Growth of Zea mays Seedlings 1  

UK PubMed Central (United Kingdom)

The electrical parameters that affect young seedling growth were investigated. Voltages ranging from 5 to 40 volts were applied longitudinally along the mesocotyl region of 4-day old Zea mays...Full Text Available

1988-08-01

433

Effect of Surgical Alteration of the Rat Gastrointestinal Tract On the Growth and Development of Hymenolepis Diminuta  

Science.gov (United States)

... Gastrointestinal Tract On the Growth and Development of Hymenolepis DiminutaKerry L. Dwinell, Paul Bass, Gordon L. Telford, ... central (CNS) nervous systems in the development of Hymenolepis diminuta usi...

434

Dynamics of Microbial Communities on Marine Snow Aggregates: Colonization, Growth, Detachment, and Grazing Mortality of Attached Bacteria  

UK PubMed Central (United Kingdom)

We studied the dynamics of microbial communities attached to model aggregates (4-mm-diameter agar spheres) and the component processes of colonization, detachment, growth, and grazing mortality. Agar...Full Text Available

2003-06-01

435

Calcitriol but no other metabolite of vitamin D is essential for normal bone growth and development in the rat.  

UK PubMed Central (United Kingdom)

To determine the relative importance of different metabolites of vitamin D in bone growth and development, weanling male rat pups suckled by vitamin D-deficient mothers were given either calcitriol...Full Text Available

1984-02-01

436

Astrocyte-Derived Vascular Endothelial Growth Factor Stabilizes Vessels in the Developing Retinal Vasculature  

UK PubMed Central (United Kingdom)

Vascular endothelial growth factor (VEGF) plays a critical role in normal development as well as retinal vasculature disease. During retinal vascularization, VEGF is most strongly expressed by not yet...Full Text Available

438

SAMS Research and Development  

Science.gov (United States)

... resolution video. RESULTS Statistics describing the typical inertial navigation error growth were collected. Typical errors ...

2008-08-06

439

Polycrystalline MBE-grown GaAs for solar cells  

Energy Technology Data Exchange (ETDEWEB)

This paper will discuss initial studies of thin-film GaAs grown by molecular-beam epitaxy for use in developing a thin-film GaAs solar cell. Photocurrent and photoluminescence intensity are related to the material morphology as a function of growth conditions. Growth temperature and V/III ratio have a dramatic effect on the photocurrent. However, it seems likely that even after optimizing such growth parameters, it will be necessary to provide substrates that can provide templates to enhance grain size from the start of thin-film growth. {copyright} {ital 1997 American Institute of Physics.}

1997-02-01

440

Liquid nitrogen dewar for protein crystal growth  

Science.gov (United States)

Gaseous Nitrogen Dewar apparatus developed by Dr. Alex McPherson of the University of California,

2001-01-01

442

Growth, Characterization and Device Development in ...  

Science.gov (United States)

... eV. In some instances the spontaneous radiation from a free electron laser system was employed to obtain images. The ...

1998-03-01

446

Advances and challenges of wood polymer composites  

Science.gov (United States)

... polypropylene, polylactic acid and polyvinyl chloride to form wood plastic composites (WPC). WPCs have seen a large growth in ... ...

447

The physics of tachyons. Pt. 2  

International Nuclear Information System (INIS)

This paper extends the development of a new formulation of the theory of tachyons to encompass the dynamics of tachyons. Energy and momentum are discussed along with the proper mass of a tachyon. The transformation of force in extended relativity (ER) is derived. Acceleration in ER is also discussed, as well as the relationship between force and acceleration. Two simple examples relating to the motion of a charged tachyon are discussed, followed by a brief explanation of why tachyons cannot emit Cerenkov radiation in a vacuum. 13 refs., 3 figs.

448

The physics of production, acceleration and neutralization of large negative ion beams  

Energy Technology Data Exchange (ETDEWEB)

Neutral beam systems for the next generation of magnetic fusion devices will be based on negative ions. Development are progressing steadily, and large negative ion-based systems are prepared for JT60-U and LHD, and are being considered for ITER. An overview of the physics of the production, acceleration and neutralization of large negative ion beams is given. the present state of the art in Research and Development is also surveyed. (author). 55 refs., 10 figs., 1 tab.

1995-12-31

449

The physics of production, acceleration and neutralization of large negative ion beams  

Energy Technology Data Exchange (ETDEWEB)

Neutral beam systems for the next generation of magnetic fusion devices will be based on negative ions. Developments are progressing steadily, and large negative ion-based systems are under preparation for JT60-U and LHD, and are being considered for ITER. An overview of the physics of the production, acceleration and neutralization of large negative ion beams is given. The present state of the art in R and D is also surveyed. (Author).

1995-11-01

450

The LLNL computer control system  

Energy Technology Data Exchange (ETDEWEB)

Lawrence Livermore National Laboratory (LLNL) has implemented a computer control system for operation of an FN tandem accelerator. The control software utilized is the Thaumaturgic Automated Control Logic (TACL) written by the Continuous Electron Beam Accelerator Facility and co-developed with LLNL. Details of the design philosophy, hardware configuration, control software, and special control algorithms will be presented. 2 refs., 4 figs.

1991-10-03

451

The Darmstadt near-infrared free-electron laser  

International Nuclear Information System (INIS)

The salient features of the near-infrared free-electron laser (FEL) that is under construction at the new Darmstadt superconducting 130-MeV electron accelerator are discussed. Special attention is given to the layout and the parameters of the accelerator, the layout of the planned FEL experiment, the characteristics of the electron gun, the subharmonic chopper-buncher system, and the hybrid undulator system of the Darmstadt FEL. A comparison of the planned Darmstadt FEL with conventional lasers, with respect to the pulse and wavelength region, is presented. 15 refs.

1989-04-24

452

Tachyons and the radiation of an accelerated charge  

Energy Technology Data Exchange (ETDEWEB)

The motion of an accelerated charge in a vacuum is analyzed, via the superposition principle and Fourier analysis, into uniform-motion components, which include bradyonic as well as tachyonic contributions. It is shown that the former contribute only to the induction fields whereas the latter are the source of the radiation emitted by the charge, via the Sommerfeld-Cerenkov mechanism. This result calls for a reexamination of some recently formulated theories of superluminal particles.

1982-10-15

453

Structure of an accelerator island with one step on double period of conserving area mapping  

International Nuclear Information System (INIS)

The structure of the P-2, S-1 accelerator mode with one step, S-1, on double period, P-2 for systems, described by the Harper mapping as well as by standard mapping, is analyzed. Detailed analysis of stability criteria is given and comparison with the results of numerical analysis is performed. Three-period compression of the P-2, S-1 island is revealed in the standard mapping. Refs. 7, figs. 7.

454

Recent developments in nuclear data for ADS  

Energy Technology Data Exchange (ETDEWEB)

Modern particle accelerators offer new opportunities to dramatically reshape the way we think about nuclear energy, and challenge some of the thorniest problems linked to its industrial use, e.g. nuclear waste. A powerful proton accelerator driving a sub-critical fission reactor could be used for producing energy more safely and burning up the extra spent fuel which so far has been stored in geological repositories.

2001-01-01

455

Potential Hazards from Neutrino Radiation at Muon Colliders  

CERN Document Server

High energy muon colliders, such as the TeV-scale conceptual designs now being considered, are found to produce enough high energy neutrinos to constitute a potentially serious off-site radiation hazard in the neighbourhood of the accelerator site. A general characterization of this radiation hazard is given, followed by an order-of-magnitude calculation for the off-site annual radiation dose and a discussion of accelerator design and site selection strategies to minimize the radiation hazard.

1999-01-01

456

Particle acceleration by stimulated emission of radiation near a solid-state active medium  

British Library Electronic Table of Contents (United Kingdom)

We report acceleration of electrons moving in free space near an active Nd:YAG slab. The power of a non-relativistic beam of electrons has increased by more than 30% when the medium was excited. It is demonstrated experimentally that the energy gained by the electrons is linearly proportional to the energy stored in the medium. Moreover, the energy gain traces closely the population inversion inferred by monitoring the spontaneous radiation.

2011-01-01

457

On-line replacement of a particle accelerator control computer  

Energy Technology Data Exchange (ETDEWEB)

This paper describes the conversion from an existing production control computer, an SEL 840, to a DEC VAX 11/780. The plan is to add a layer of hardware to accomplish a smooth and gradual transition from the 840 to the VAX while leaving the underlying equipment unchanged. The architecture of the control system software is discussed for a large linear accelerator from the standpoint of its requirements and the particular design philosophy chosen.

1981-01-01

458

Long term accelerated aging tests on distribution cables under wet conditions  

Energy Technology Data Exchange (ETDEWEB)

Two accelerated aging test procedures are proposed for use on solid dielectric extruded distribution cables under wet conditions. One test method is a fixed time duration test in which the degree of cable specimen aging is assessed in terms of breakdown tests, while the other test method is a time to breakdown test in which the cable specimens are voltage stressed until failure ensues.

1996-10-01

459

JAERI TANDEM annual report 2000. April 1, 2000 - March 31, 2001  

Energy Technology Data Exchange (ETDEWEB)

This annual report describes research activities which have been performed with the JAERI tandem accelerator and the Van de Graaff accelerator from April 1, 2000 to March 31, 2001. Summary reports of 46 papers, and lists of publication, personnel and cooperative research with universities are contained. (author)

2001-11-01

460

High-brightness photoemitter development for electron accelerator injectors  

Energy Technology Data Exchange (ETDEWEB)

Free-electron-laser (FEL) oscillators require a train of high-brightness bunches. Conventional subharmonic bunchers are currently used with rf linacs to generate pulse trains, but the resulting dilution of the transverse phase space and lower beam brightness are unacceptable for high-performance FELs. Recent developments suggest that photoemitters of high quantum efficiency combined with rapid acceleration can produce pulse trains of higher brightness than has been achieved before.

1985-01-01

461

Evaluation of high temperature accelerated aging tests used on integrated circuits. Final report  

Energy Technology Data Exchange (ETDEWEB)

Accelerated aging tests such as high temperature burn-in, which are in current use on Bendix Kansas City Division's (BKC) purchased small and medium scale integrated circuits, were evaluated to determine if they are effective and necessary to ensure the required reliability. A theoretical analysis, a literature search, and a study of lot acceptance results were used to assess the value of integrated circuit burn-in.

1986-04-01

462

Electron linear accelerators for radiotherapy  

International Nuclear Information System (INIS)

Present-day requirements for radiotherapy equipment are considered. The recently developed linacs of LUE-5, LUE-25, LUE-15MM models, as well as a newly designed unified series of medical linacs of LUER-5M, LUER-20M, LUER-40M models are described in brief. The main scientific and technical problems that were solved during their construction, namely, development of accelerating structures, a radiation head, dosimetry equipment, a programming unit, a magnetic mirror etc. are described.

1983-06-01

463

Electron beam and high-speed optical diagnostics for the Los Alamos HIBAF (High Brightness Accelerator FEL) Facility  

Energy Technology Data Exchange (ETDEWEB)

Characterization of the electron beam's properties will be a major task after the upgrade of the Los Alamos Free-Electron Laser (FEL) Facility with a photoelectric injector (PEI) and increased acceleration capability to 40 MeV. Adjustments to the previous diagnostics package that address the lower beam emittance, higher energy, and wakefield source reduction issues will be discussed. 6 refs., 8 figs., 1 tab.

1989-01-01

464

Electron accelerator unit for electron beam therapy  

Energy Technology Data Exchange (ETDEWEB)

An electron accelerator unit is described for electron beam therapy, comprising: a source of an electron beam; means for finally directing at least a portion of the beam to a therapy site, the directing means being mechanically independent of, and electrically isolated from, the source, and having a target area; and means for aligning the source with the directing means, the aligning means comprising means for projecting at least one beam of light from the source toward the target area.

1987-01-27

465

Electron accelerator unit for electron beam therapy  

International Nuclear Information System (INIS)

An electron accelerator unit is described for electron beam therapy, comprising: a source of an electron beam; means for finally directing at least a portion of the beam to a therapy site, the directing means being mechanically independent of, and electrically isolated from, the source, and having a target area; and means for aligning the source with the directing means, the aligning means comprising means for projecting at least one beam of light from the source toward the target area.

466

Early Experience in Using an 18 MeV Linear Accelerator for Mycosis Fungoides at Howard University Hospital  

UK PubMed Central (United Kingdom)

This paper describes the problems and solutions in using 18 MeV linear accelerator, with minimum 6 MeV electron capability, for total skin irradiation for mycosis fungoides. The 6 MeV electron energy...Full Text Available

1977-04-01

467

Decay-accelerating factor CD55 is identified as the receptor for echovirus 7 using CELICS, a rapid immuno-focal cloning method.  

UK PubMed Central (United Kingdom)

Using an anti-receptor mAb that blocks the attachment of echovirus 7 and related viruses (echoviruses 13, 21, 29 and 33), we have isolated a complementary DNA clone that encodes the human decay-accelerating...Full Text Available

1994-11-01

468

DIPAC 2005 7. European workshop on beam diagnostics and instrumentation for particle accelerators  

Energy Technology Data Exchange (ETDEWEB)

Accelerators can not be improved without the development of adequate beam instruments and diagnostic tools. This year this statement is particularly right: a lot of contributions are dedicated to beam monitoring and to the design of new beam monitors based on original technologies. This document gathers about 100 contributions.

2005-07-01

469

Cosmological BCS condensate as dark energy  

CERN Document Server

We argue that the occurrence of late-time acceleration can conveniently be described by first-order general relativity covariantly coupled to fermions. Dark energy arises as a gravitationally driven BCS condensate of fermions which forms in the early universe. At late times, the gap and chemical potential evolve to have an equation of state with effective negative pressure, thus naturally leading to acceleration.

2009-01-01

470

Contribution of pulsars to the cosmic rays in the Galaxy  

Energy Technology Data Exchange (ETDEWEB)

The contribution of pulsar accelerated nuclei to the cosmic rays inside the Galaxy is calculated assuming that a significant part of the pulsar rotational energy is lost on acceleration of iron nuclei extracted from the surface of the neutron star. Different models of the galactic pulsar population are discussed. It is shown that the best description of the observed cosmic ray spectrum and the mass composition between a few 10{sup 15} eV and a few 10{sup 18} eV is obtained for the model B of Lorimer et al. (1993)

2004-11-15

471

Computer modeling of two-phase flow  

Science.gov (United States)

The accelerating flow of a lighter continuous phase through a heavier one is considered. Small nonuniformities grow into large ones due to the Rayleigh-Taylor instability. An experiment exemplifying the large bubble formation due to Rayleigh-Taylor instability was performed and simulated using the PHOENICS 84 computer code. The same numerical procedure was applied to the two-phase flow in a gun barrel. It shows that the acceleration provided by the movement of the projectile can cause initial nonuniformities to grow with time.

1986-10-01

472

Assessment of the efficacy of braking radiation beam formation of electron accelerators  

International Nuclear Information System (INIS)

Proceeding from analysis of the influence of parameters of the target-filter system on radiation-physical characteristics of braking radiation, some recommendations were issued for assessment of the forming systems of medical accelerators of electrons. A new criterion - a coefficient of the forming system efficacy - was introduced, characterizing a beam formation tract with relation to a whole set of radiotherapeutic problems.

473

Annotated bibliography of Accelerator Technology Division research and development, 1978-1985  

International Nuclear Information System (INIS)

A bibliography is presented of unclassified published and in-house technical material written by members of the Accelerator Technology Division, Los Alamos National Laboratory, since its inception in January, 1978. The author and subject concordances in this report provide cross-reference to detailed citations kept in a computer database and a microfilm file of the documents. The citations include an abstract and other notes, and can be searched for key words and phrases.

474

Analysis of longitudinal bunching in an FEL driven two-beam accelerator  

Energy Technology Data Exchange (ETDEWEB)

Recent experiments have explored the use of a free-electron laser (FEL) as a buncher for a microwave two-beam accelerator, and the subsequent driving of a standing-wave rf output cavity. Here the authors present a deeper analysis of the longitudinal dynamics of the electron bunches as they are transported from the end of the FEL and through the output cavity. In particular, the authors examine the effect of the transport region and cavity aperture to filter the bunched portion of the beam.

2000-08-01

475

An S-brane solution with acceleration and small enough variation of G  

CERN Document Server

An S-brane solution with two non-composite electric branes and a set of l scalar fields is considered. The intersection rule for branes corresponds to the Lie algebra A_2. The solution contains five factor spaces with the fifth one interpreted as ``our'' 3-dimensional space. It is shown that there exists a time interval where accelerating expansion of ``our'' 3-dimensional space is compatible with small enough value of effective gravitational ``constant'' variation.

2007-01-01

476

Accelerator aspects of {gamma}-{gamma} colliders  

Energy Technology Data Exchange (ETDEWEB)

There are several on-going projects of e{sup +}e{sup -} colliders. If they are constructed, we can convert them into photon-photon ({gamma}-{gamma}) colliders by converting electron beams into {gamma} beams, irradiating laser beams just before the interaction point. In this report we discuss the technical issues on the accelerator.

2000-11-21

477

Accelerating the convergence of self-consistent linearized augmented-plane-wave calculations  

International Nuclear Information System (INIS)

The applicability of Broyden's second method for accelerating the convergence of self-consistent electronic-structure calculations based on the linearized augmented-plane-wave method is discussed in terms of a W(001) surface calculation. It is found that its use results in a significant improvement in the convergence of the calculation, and based on this it is concluded that its use should increase the size of the systems for which such calculations are feasible.

478

Accelerated aging tests with a resid hydrotreating catalyst  

International Nuclear Information System (INIS)

The author discusses the accelerated aging tests performed using Hondo and Maya as aging resids with a commercial large pore hydrotreating catalyst. The results from these tests were compared with those obtained under a normal full life test. The test resid was a sample of a typical refinery charge and the activities for sulfur and vanadium removal were determined at 720"0F after successive brief periods of exposure to the heavier oils.

1988-12-02

479

Accelerated aging speeds test of instrument reliability  

International Nuclear Information System (INIS)

Safety-related instrument in nuclear power plants must be checked for reliability over their projected operating life. A method of conducting accelerated aging tests is presentd. It uses the Arrhenius activation energy concept and manipulation of the parameters of the test e.g. by raising test temperature, by relying on a model characterizing the chemical-related reactions of materials.

1982-01-01

480

Sensing the physical and nutritional status of the root growth environment  

Environmental Research Database

DescriptionAbstract of Research Proposal The root environment has a major effect on crop growth, both directly through the supply of water and nutrients to the shoot, and indirectly through root to shoot signalling. Better management of crop root systems through agronomic and genetic means has the potential to improve the efficiency of water and nutrient uptake, and limit root restrictions to crop growth. However, progress in this area is currently limited by the lack of sensors for in situ estimates of [continued...

2004-01-30

481

Morphological Instabilities in a growing Yeast Colony Experiment and Theory  

CERN Document Server

We study the growth of colonies of the yeast Pichia membranaefaciens on agarose film. The growth conditions are controlled in a setup where nutrients are supplied through an agarose film suspended over a solution of nutrients. As the thickness of the agarose film is varied, the morphology of the front of the colony changes. The growth of the front is modeled by coupling it to a diffusive field of inhibitory metabolites. Qualitative agreement with experiments suggests that such a coupling is responsible for the observed instability of the front.

1997-01-01

482

Increased Endogenous Abscisic Acid Maintains Primary Root Growth and Inhibits Shoot Growth of Maize Seedlings at Low Water Potentials 1  

UK PubMed Central (United Kingdom)

Roots of maize (Zea mays L.) seedlings continue to grow at low water potentials that cause complete inhibition of shoot growth. In this study, we have investigated the role of abscisic...Full Text Available

1990-08-01

483

Hair shaft elongation, follicle growth, and spontaneous regression in long-term, gelatin sponge-supported histoculture of human scalp skin.  

UK PubMed Central (United Kingdom)

In order to better understand the molecular mechanisms of human hair growth control and to test hair growth-modulatory drugs, appropriate in vitro models are required. Here, we report the long-term...Full Text Available

1992-09-15

484

Growth differentiation factor-9 stimulates progesterone synthesis in granulosa cells via a prostaglandin E2/EP2 receptor pathway  

UK PubMed Central (United Kingdom)

Growth differentiation factor-9 (GDF-9), an oocyte-secreted member of the transforming growth factor β superfamily, progesterone receptor, cyclooxygenase 2 (Cox2; Ptgs2), and the EP2 prostaglandin...Full Text Available

2000-08-29

485

Effects of Short-Term Treadmill Exercise Training or Growth Hormone Supplementation on Diastolic Function and Exercise Tolerance in Old Rats  

UK PubMed Central (United Kingdom)

Whether the lusitropic potential of short-term exercise in aged rats is linked to an augmentation in the growth hormone/insulin-like growth factor-1 (GH/IGF-1) axis and an alteration in the...Full Text Available

2008-09-01

486

Effect of WC particle size on grain growth inhibition in the WC-xVC-Co system  

Energy Technology Data Exchange (ETDEWEB)

The effect of WC particle size with the addition of VC as a grain growth inhibitor was investigated during the liquid phase sintering of WC-Co system. With increasing WC particle size at the same VC content, the effect of grain growth inhibition was increased. Also, with increasing the VC content, the grain shape of WC was changed from the faceted shape to the distorted shape, and the step density of the WC grain was increased. (orig.)

2003-07-01

487

An interface - marker technique applied to the study of metal silicide growth  

International Nuclear Information System (INIS)

An interface-marker technique has been used to investigate the relative rates of diffusion of Si and of metal atoms during the growth of metal silicide films. The technique enables recognition of a reference plane in thin film diffusion using Rutherford backscattering, while minimizing any perturbation of the diffusion process. Examples are drawn from studies of the growth of silicides of W, Mo, Ta, Nb, Pd and Pt. (orig.).

488

Using Gamma-Ray Burst Prompt Emission to Probe Relativistic Shock Acceleration  

CERN Document Server

It is widely accepted that the prompt transient signal in the 10 keV - 10 GeV band from gamma-ray bursts (GRBs) arises from multiple shocks internal to the ultra-relativistic expansion. The detailed understanding of the dissipation and accompanying acceleration at these shocks is a currently topical subject. This paper explores the relationship between GRB prompt emission spectra and the electron (or ion) acceleration properties at the relativistic shocks that pertain to GRB models. The focus is on the array of possible high-energy power-law indices in accelerated populations, highlighting how spectra above 1 MeV can probe the field obliquity in GRB internal shocks, and the character of hydromagnetic turbulence in their environs. It is emphasized that diffusive shock acceleration theory generates no canonical spectrum at relativistic MHD discontinuities. This diversity is commensurate with the ...

2010-01-01

489

Multi-beamlet focusing of intense negative ion beams by aperture displacement technique  

Energy Technology Data Exchange (ETDEWEB)

Multi-beamlet focusing of an intense negative ion beam has been performed using the beamlet steering by the aperture displacement. The apertures of the grounded grid were displaced as all beamlets of 270 (18 x 15) in the area of 25 cm x 26 cm would be steered to a common point (a focal point) in both the two-stage and the single-stage accelerators. The multi-beamlets were successfully focused and the e-folding half width of 10 cm was achieved 11.2 m downstream from the ion source in both the accelerators. The corresponding gross divergence angle is 9 mrad. The negative ion beamlets are deflected by the magnetic field for the electron deflection at the extraction grid and the deflection direction oppositely changes line by line, resulting in the beam split in the deflection direction. This beamlet deflection was well compensated also using the beamlet steering by the aperture displacement of the grounded grid. The beam ...

1995-08-01

490

Life evaluation of insulating materials for electric cable by accelerated thermal-radiation combined aging. 2  

International Nuclear Information System (INIS)

Radiation-and-thermal-combined degradation of some kinds of cable insulating and jacketing materials was evaluated by accelerated aging tests. Plasticized polyvinyl chloride (PVC), silicone rubber, crosslinked and non-crosslinked halogen-free flame-retardant polyolefins (NH-XLPO and NH-PO) and ethylene-propylene rubber (EP rubber) of experimental formulation were degraded at accelerated rates, that are 50-1000 times the degradation rate under standard conditions (e.g.; 1Gy/h, 50degC), and a method to assess the lifetime of these materials under standard conditions was studied. The degradation was investigated by measuring tensile properties. In the accelerated aging tests, rates of elongation decrease owing to degradation for these materials were in proportion to the increase in accelerated rate. The PVC lifetime estimated from sequential aging tests had a tendency to extend beyond that from ...

1994-01-01

491

Lie Algebraic Treatment of Linear and Nonlinear Beam Dynamics  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to present a summary of new methods, employing Lie algebraic tools, for characterizing beam dynamics in charged-particle optical systems. These methods are applicable to accelerator design, charged-particle beam transport, electron microscopes, and also light optics. The new methods represent the action of each separate element of a compound optical system, including all departures from paraxial optics, by a certain operator. The operators for the various elements can then be concatenated, following well-defined rules, to obtain a resultant operator that characterizes the entire system. This paper deals mostly with accelerator design and charged-particle beam transport. The application of Lie algebraic methods to light optics and electron microscopes is described elsewhere (1, see also 44). To keep its scope within reasonable bounds, they restrict their treatment of accelerator design and ...

1988-12-01

492

Relaxant effects of hexosamines on isolated small human placental arteries  

DEFF Research Database (Denmark)

Wharton's jelly contains large amounts of hyaluronic acid, and glucosamine is an important constituent of this macromolecule. In order to evaluate the placental vascular effects of this aminosugar, small chorionic and stem villous arteries were dissected from placental specimens obtained at normal term vaginal deliveries (n = 15). Ring preparations were mounted in organ baths, and isometric wall tensions were measured. Glucosamine and its epimer galactosamine (5 X 10(-4) to 10(-2) M) produced marked relaxation of contractions induced by PGF2 alpha (10(-5) M) in both chorionic and stem villous arteries. The effect was unchanged after pretreatment with atropin, propranolol and indomethacin. The relaxant effect of the neutral sugar mannose was less pronounced compared with that of the hexosamines. Total tissue concentrations of placental hexosamines have been reported within the range needed to produce placental vascular relaxation in the present ...

1987-01-01

493

Identification of tumor-initiating cells in a p53-null mouse model of breast cancer.  

Science.gov (United States)

Using a syngeneic p53-null mouse mammary gland tumor model that closely mimics human breast cancer, we have identified, by limiting dilution transplantation and in vitro mammosphere assay, a Lin(-)CD29(H)CD24(H) subpopulation of tumor-initiating cells. Upon subsequent transplantation, this subpopulation generated heterogeneous tumors that displayed properties similar to the primary tumor. Analysis of biomarkers suggests the Lin(-)CD29(H)CD24(H) subpopulation may have arisen from a bipotent mammary progenitor. Differentially expressed genes in the Lin(-)CD29(H)CD24(H) mouse mammary gland tumor-initiating cell population include those involved in DNA damage response and repair, as well as genes involved in epigenetic regulation previously shown to be critical for stem cell self-renewal. These studies provide in vitro and in vivo data that support the cancer stem cell (CSC) hypothesis. Furthermore, this p53-null mouse mammary tumor model may allow ...

2008-06-15

494

Free-air CO{sub 2} enrichment (FACE) enhances biomass production in a short-rotation poplar plantation  

Energy Technology Data Exchange (ETDEWEB)

The possible contribution of short rotation cultures (SRC) to carbon sequestration in both current and elevated carbon dioxide concentrations was investigated using the free-air carbon dioxide enrichment (FACE) technique. Three poplar species were grown in an SRC plantation for three growing seasons. Above-ground and below-ground biomass increased by 15 to 27 per cent and by 22 to 38 per cent, respectively; light-efficiency also increased as a result. Depletion of inorganic nitrogen from the soil increased after three growing seasons at elevated carbon dioxide levels, but carbon dioxide showed no effect on stem wood density. Stem wood density also differed significantly from species to species. These results confirmed inter-specific differences in biomass production in poplar, and demonstrated that elevated carbon dioxide enhanced biomass productivity and light-use efficiency of a poplar short rotation cultivation ecosystem without changing ...

2003-08-01

495

Free-air CO_2 enrichment (FACE) enhances biomass production in a short-rotation poplar plantation  

International Nuclear Information System (INIS)

The possible contribution of short rotation cultures (SRC) to carbon sequestration in both current and elevated carbon dioxide concentrations was investigated using the free-air carbon dioxide enrichment (FACE) technique. Three poplar species were grown in an SRC plantation for three growing seasons. Above-ground and below-ground biomass increased by 15 to 27 per cent and by 22 to 38 per cent, respectively; light-efficiency also increased as a result. Depletion of inorganic nitrogen from the soil increased after three growing seasons at elevated carbon dioxide levels, but carbon dioxide showed no effect on stem wood density. Stem wood density also differed significantly from species to species. These results confirmed inter-specific differences in biomass production in poplar, and demonstrated that elevated carbon dioxide enhanced biomass productivity and light-use efficiency of a poplar short rotation cultivation ecosystem without changing ...

2003-08-01

496

Extreme sensitivity of some intestinal crypt cells to X and #gamma# irradiation  

International Nuclear Information System (INIS)

Reference is made to Cheng and Leblond (Amer. J. Anat.; 141:537 (1974)) who used tritiated thymidine to kill cells synthesising DNA in the crypts of the small intestine. Amongst their findings was that very low doses caused measurable cell killing and that the killing was not random throughout the crypt but occurred selectively at the crypt base where stem cells are presumably located. It is here reported that the presence of hypersensitive cells at the base of the crypts can be demonstrated after whole-body X- or gamma-irradiation, and the time sequence for the production and loss of the killed cells is described together with their dose-response relationship. The studies were conducted on mice. The data were expressed as surviving rather than killed cells, and it was established that the crypt are amongst the most sensitive of mammalian cells. The mechanism by which these sensitive cells are killed is not known, but DNA damage can be detected. The vital ...

1977-10-01

497

Elimination of a new ampelovirus (GLRaV-Pr) and Grapevine rupestris stem pitting associated virus (GRSPaV) from two Vitis vinifera cultivars combining in vitro thermotherapy with shoot tip culture  

British Library Electronic Table of Contents (United Kingdom)

A new virus species designated as Grapevine leafroll associated virus-Pr (GLRaV-Pr), which is classified in a distinct phylogenetic group of the genus Ampelovirus (Closteroviridae), was recently characterized from Greek grapevine cultivars. Elimination studies of GLRaV-Pr were carried out in two grapevine cultivars, 'Mantilaria' and 'Prevezaniko', co-infected with Grapevine rupestris stem pitting associated virus (GRSPaV, Flexiviridae). Both viruses were detected by nested RT-PCR assays. Virus elimination was achieved by combining in vitro thermotherapy with meristem ( 0.2mm) or shoot tip culture ( 0.5cm). The survival and regeneration rate of meristems was very low. On the other hand, high survival rates were observed in the cultured shoot tips accompanied with high elimination rates for ...

2009-01-01