New measurements of the 6190-A band of methane

NASA Technical Reports Server (NTRS)

Mickelson, M. E.; Larson, L. E.; Schubert, A.

1991-01-01

The present paper reports new laboratory measurements that were made of the absorption coefficient of the visible methane band at 6190 A. Data were obtained using a tunable dye laser system operating with a line width of 0.067/cm. Spectra were recorded at approximately 1-A intervals with the beam coupled to a 22-m base length White-type absorption cell adjusted for an optical path of 1584 km and filled to a density of 0.884 amagats. Errors in pressure, temperature, and path length amounted to an uncertainty in the abundance of no more than 0.4 percent. Fourteen data sets were recorded and coadded. The final signal-averaged methane data were divided by a similar set of signal-averaged empty cell scans to remove the transmittance of the White cell and system optics. The results are compared with previous low-resolution measurements in the spectral region from 6000 to 6400 A.

Effects of fluctuations on electrical properties of gap-junction connected cells in the turtle retina.

PubMed

Louis, E; Degli Esposti Boschi, C; Ortega, G; Andreu, E; Fernández, E; Sánchez-Andrés, J V

2002-04-19

Electrical properties of gap-junction connected cells (input voltage and length constant) are shown to depend strongly on fluctuations in membrane and contact conductances. This opens new possibilities and incorporates a further difficulty to the analysis of electrophysiological data, since four, instead of two, parameters (the average values and the magnitude of fluctuations of the two conductances) have to be used in fitting the experimental data. The discussion is illustrated by investigating the effects of dopamine on signal spreading in horizontal cells of turtle retina, assuming a linear cell arrangement. It is shown that while a standard fitting with the average values of the two conductances leads to the conclusion that both are equally affected by dopamine, including fluctuations allows fitting the data by varying just the average contact conductance plus the magnitude of fluctuations.

Cow characteristics and their association with udder health after different dry period lengths.

PubMed

van Hoeij, R J; Lam, T J G M; de Koning, D B; Steeneveld, W; Kemp, B; van Knegsel, A T M

2016-10-01

Shortening or omitting the dry period (DP) in dairy cows is of interest because of potential beneficial effects on energy balance and metabolic health. Reported effects of a short or omitted dry period on udder health are ambiguous. This study aimed to evaluate the effect of no DP (0d), a short DP (30d), or a conventional DP (60 d) on the occurrence of intramammary infections (IMI) during the precalving period and on somatic cell counts (SCC), elevations of SCC (SCC≥200,000 cells/mL), and clinical mastitis in the subsequent lactation. The study also aimed to analyze which prepartum cow characteristics are associated with udder health after different DP lengths. Holstein-Friesian dairy cows (n=167) were randomly assigned to a DP length (0, 30, or 60 d). Cows with a 0-d DP had a greater occurrence of chronic IMI and a lower occurrence of cured IMI during the precalving period than cows with a 30-d or 60-d DP. Postpartum average SCC for lactation was greater in cows with a 0-d DP than in cows with a 30-d or 60-d DP. The number of cows with at least 1 elevation of SCC, the number of elevations of SCC per affected cow, the number of cows treated for clinical mastitis, and the number of cases of mastitis per affected cow did not differ among DP lengths. Cow characteristics related to postpartum average SCC for lactation were DP length, parity, and the following interactions: DP length with prepartum elevation of SCC, DP length with fat- and protein-corrected milk (FPCM) reduction between 150 and 67d prepartum, DP length with parity and with average SCC for lactation, and last FPCM before the conventional drying-off day with average SCC for lactation. Cows with prepartum parity 1 had a lower occurrence of at least 1 elevation of SCC in subsequent lactation compared with cows with parity >2. Last SCC before the conventional drying-off day was positively associated with occurrence of clinical mastitis in the subsequent lactation. In this study, DP length was not a risk factor for either elevation of SCC or occurrence of clinical mastitis in the subsequent lactation. The identified cow characteristics could be used in a decision support model to optimize DP length for individual cows. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Transfusion of red blood cells: no impact on length of hospital stay in moderately anaemic parturients.

PubMed

Palo, R; Ahonen, J; Salo, H; Salmenperä, M; Krusius, T; Mäki, T

2007-05-01

In a search for information to improve decision making on red blood cell (RBC) transfusion, we examined the impact of RBC transfusion on the length of hospital stay for delivery in moderately anaemic women (haemoglobin, 7-10 g/dl). This was a retrospective, observational study covering 2 years (2002 and 2003), and included major blood-transfusing hospitals from four university and five central hospital districts managing 67.5% of Finnish in-hospital deliveries. The impact of the transfusion of 1-2 RBC units vs. no transfusion on the length of hospital stay was evaluated for three different haemoglobin levels: 7-7.9, 8-8.9 and 9-10 g/dl. Of the 1954 moderately anaemic mothers in hospital for delivery, 13.3% were transfused with RBC. The mean length of hospital stay was 5.2 days vs. the average Finnish hospital delivery stay of 3.5 days. No differences in stay were found between patients with comparable anaemia transfused with 1-2 RBC units or none (at the three haemoglobin levels: P= 0.50, P= 0.07 and P= 0.54, respectively). The final haemoglobin value was higher (P < 0.001) in transfused patients. The duration of admission for delivery in moderately anaemic parturients was longer than the average length of hospital stay in Finnish parturients. However, 1-2 RBC units had no impact on the length of stay, suggesting that unnecessary RBCs are transfused after delivery. Thus, transfusion practices in obstetrics are not always optimal.

Photoinactivation of Latent Herpes Simplex Virus in Rabbit Kidney Cells

PubMed Central

Kelleher, J. J.; Varani, J.

1976-01-01

The photoinactivation of actively and nonactively growing herpes simplex virus by neutral red and proflavine was studied in rabbit kidney cells. Active virus growth was inhibited by both dyes under conditions which did not destroy the cells. Neutral red caused a much greater inhibition than proflavine. Neutral red also caused a reduction in the reactivation rate of latent virus when the infected cells were treated during the latent period. In the treated cultures that did reactivate virus, the average length of the latent period was increased over the control value. Proflavine treatment did not reduce the rate of reactivation of latent virus and did not increase the average latent period of the treated cultures. PMID:185948

Visualization and quantitative analysis of extrachromosomal telomere-repeat DNA in individual human cells by Halo-FISH

PubMed Central

Komosa, Martin; Root, Heather; Meyn, M. Stephen

2015-01-01

Current methods for characterizing extrachromosomal nuclear DNA in mammalian cells do not permit single-cell analysis, are often semi-quantitative and frequently biased toward the detection of circular species. To overcome these limitations, we developed Halo-FISH to visualize and quantitatively analyze extrachromosomal DNA in single cells. We demonstrate Halo-FISH by using it to analyze extrachromosomal telomere-repeat (ECTR) in human cells that use the Alternative Lengthening of Telomeres (ALT) pathway(s) to maintain telomere lengths. We find that GM847 and VA13 ALT cells average ∼80 detectable G/C-strand ECTR DNA molecules/nucleus, while U2OS ALT cells average ∼18 molecules/nucleus. In comparison, human primary and telomerase-positive cells contain <5 ECTR DNA molecules/nucleus. ECTR DNA in ALT cells exhibit striking cell-to-cell variations in number (<20 to >300), range widely in length (<1 to >200 kb) and are composed of primarily G- or C-strand telomere-repeat DNA. Halo-FISH enables, for the first time, the simultaneous analysis of ECTR DNA and chromosomal telomeres in a single cell. We find that ECTR DNA comprises ∼15% of telomere-repeat DNA in GM847 and VA13 cells, but <4% in U2OS cells. In addition to its use in ALT cell analysis, Halo-FISH can facilitate the study of a wide variety of extrachromosomal DNA in mammalian cells. PMID:25662602

LINDENS: A program for lineament length and density analysis*1

NASA Astrophysics Data System (ADS)

Casas, Antonio M.; Cortés, Angel L.; Maestro, Adolfo; Soriano, M. Asunción; Riaguas, Andres; Bernal, Javier

2000-11-01

Analysis of lineaments from satellite images normally includes the determination of their orientation and density. The spatial variation in the orientation and/or number of lineaments must be obtained by means of a network of cells, the lineaments included in each cell being analysed separately. The program presented in this work, LINDENS, allows the density of lineaments (number of lineaments per km 2 and length of lineaments per km 2) to be estimated. It also provides a tool for classifying the lineaments contained in different cells, so that their orientation can be represented in frequency histograms and/or rose diagrams. The input file must contain the planar coordinates of the beginning and end of each lineament. The density analysis is done by creating a network of square cells, and counting the number of lineaments that are contained within each cell, that have one of their ends within the cell or that cross-cut the cell boundary. The lengths of lineaments are then calculated. To obtain a representative density map the cell size must be fixed according to: (1) the average lineament length; (2) the distance between the lineaments; and (3) the boundaries of zones with low densities due to lithology or outcrop features. An example from the Neogene Duero Basin (Northern Spain) is provided to test the reliability of the density maps obtained with different cell sizes.

Kinetic analysis of F-actin depolymerization in polymorphonuclear leukocyte lysates indicates that chemoattractant stimulation increases actin filament number without altering the filament length distribution

PubMed Central

1991-01-01

The rate of filamentous actin (F-actin) depolymerization is proportional to the number of filaments depolarizing and changes in the rate are proportional to changes in filament number. To determine the number and length of actin filaments in polymorphonuclear leukocytes and the change in filament number and length that occurs during the increase in F-actin upon chemoattractant stimulation, the time course of cellular F-actin depolymerization in lysates of control and peptide- stimulated cells was examined. F-actin was quantified by the TRITC- labeled phalloidin staining of pelletable actin. Lysis in 1.2 M KCl and 10 microM DNase I minimized the effects of F-actin binding proteins and G-actin, respectively, on the kinetics of depolymerization. To determine filament number and length from a depolymerization time course, depolymerization kinetics must be limited by the actin monomer dissociation rate. Comparison of time courses of depolymerization in the presence (pointed ends free) or absence (barbed and pointed ends free) of cytochalasin suggested depolymerization occurred from both ends of the filament and that monomer dissociation was rate limiting. Control cells had 1.7 +/- 0.4 x 10(5) filaments with an average length of 0.29 +/- 0.09 microns. Chemo-attractant stimulation for 90 s at room temperature with 0.02 microM N-formylnorleucylleucylphenylalanine caused a twofold increase in F-actin and about a two-fold increase in the total number of actin filaments to 4.0 +/- 0.5 x 10(5) filaments with an average length of 0.27 +/- 0.07 microns. In both cases, most (approximately 80%) of the filaments were quite short (less than or equal to 0.18 micron). The length distributions of actin filaments in stimulated and control cells were similar. PMID:1918158

Telomere Restriction Fragment (TRF) Analysis.

PubMed

Mender, Ilgen; Shay, Jerry W

2015-11-20

While telomerase is expressed in ~90% of primary human tumors, most somatic tissue cells except transiently proliferating stem-like cells do not have detectable telomerase activity (Shay and Wright, 1996; Shay and Wright, 2001). Telomeres progressively shorten with each cell division in normal cells, including proliferating stem-like cells, due to the end replication (lagging strand synthesis) problem and other causes such as oxidative damage, therefore all somatic cells have limited cell proliferation capacity (Hayflick limit) (Hayflick and Moorhead, 1961; Olovnikov, 1973). The progressive telomere shortening eventually leads to growth arrest in normal cells, which is known as replicative senescence (Shay et al. , 1991). Once telomerase is activated in cancer cells, telomere length is stabilized by the addition of TTAGGG repeats to the end of chromosomes, thus enabling the limitless continuation of cell division (Shay and Wright, 1996; Shay and Wright, 2001). Therefore, the link between aging and cancer can be partially explained by telomere biology. There are many rapid and convenient methods to study telomere biology such as Telomere Restriction Fragment (TRF), Telomere Repeat Amplification Protocol (TRAP) (Mender and Shay, 2015b) and Telomere dysfunction Induced Foci (TIF) analysis (Mender and Shay, 2015a). In this protocol paper we describe Telomere Restriction Fragment (TRF) analysis to determine average telomeric length of cells. Telomeric length can be indirectly measured by a technique called Telomere Restriction Fragment analysis (TRF). This technique is a modified Southern blot, which measures the heterogeneous range of telomere lengths in a cell population using the length distribution of the terminal restriction fragments (Harley et al. , 1990; Ouellette et al. , 2000). This method can be used in eukaryotic cells. The description below focuses on the measurement of human cancer cells telomere length. The principle of this method relies on the lack of restriction enzyme recognition sites within TTAGGG tandem telomeric repeats, therefore digestion of genomic DNA, not telomeric DNA, with a combination of 6 base restriction endonucleases reduces genomic DNA size to less than 800 bp.

Manipulation of cells' position across a microfluidic channel using a series of continuously varying herringbone structures

NASA Astrophysics Data System (ADS)

Jung, Yugyung; Hyun, Ji-chul; Choi, Jongchan; Atajanov, Arslan; Yang, Sung

2017-12-01

Controlling cells' movement is an important technique in biological analysis that is performed within a microfluidic system. Many external forces are utilized for manipulation of cells, including their position in the channel. These forces can effectively control cells in a desired manner. Most of techniques used to manipulate cells require sophisticated set-ups and equipment to generate desired effect. The exception to this is the use of hydrodynamic force. In this study, a series of continuously varying herringbone structures is proposed for positioning cells in a microfluidic channel using hydrodynamic force. This structure was experimentally developed by changing parameters, such as the length of the herringbone's apex, the length of the herringbone's base and the ratio of the height of the flat channel to the height of the herringbone structure. Results of this study, have demonstrated that the length of the herringbone's apex and the ratio of the heights of the flat channel and the herringbone structure were crucial parameters influencing positioning of cells at 100 μl/h flow rate. The final design was fixed at 170 and 80 μm for the length of herringbone's apex and the length of herringbone's base, respectively. The average position of cells in this device was 34 μm away from the side wall in a 200 μm wide channel. Finally, to substantiate a practical application of the herringbone structure for positioning, cells were randomly introduced into a microfluidic device, containing an array of trapping structures together with a series of herringbone structures along the channel. The cells were moved toward the trapping structure by the herringbone structure and the trapping efficiency was increased. Therefore, it is anticipated that this device will be utilized to continuously control cells' position without application of external forces.

Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

NASA Astrophysics Data System (ADS)

Burghoorn, M.; Kniknie, B.; van Deelen, J.; Xu, M.; Vroon, Z.; van Ee, R.; van de Belt, R.; Buskens, P.

2014-12-01

Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (Jsc) and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-)selenide (CIGS) solar cells is also optically advantageous. Here, we experimentally demonstrate that the Jsc and efficiency of CIGS solar cells with an absorber layer thickness (dCIGS) of 0.85 μm, 1.00 μm and 2.00 μm increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (nresist = 1.792 vs. nAZO = 1.913 at 633 nm) to avoid large optical losses at the resist-AZO interface. On average, Jsc increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%). No trend towards a larger relative increase in Jsc with decreasing dCIGS was observed. Ergo, the increase in Jsc can be fully explained by the reduction in reflection, and we did not observe any increase in Jsc based on an increased photon path length.

Evaluation of the Ganglion Cell Complex and Retinal Nerve Fiber Layer in Low, Moderate, and High Myopia: A Study by RTVue Spectral Domain Optical Coherence Tomography.

PubMed

Sezgin Akcay, Betul Ilkay; Gunay, Betul Onal; Kardes, Esra; Unlu, Cihan; Ergin, Ahmet

2017-01-01

To assess the effect of low, moderate, and high myopia on the thickness of the retinal nerve fiber layer (RNFL) and Ganglion cell complex (GCC) measured by Spectral Domain Optical Coherence Tomography (SD-OCT) in non-glaucomatous subjects. The subjects were divided into three groups: low (n = 81, 35.6%), moderate (n = 79, 34.8%), and highly myopic eyes (n = 67, 29.5%). The RNFL thickness profile, including the average, superior, nasal, inferior, and temporal quadrant and each of the eight directional thicknesses, was measured. GCC parameters, including the average, superior, and inferior values, the focal loss volume (FLV), and the global loss volume (GLV), were measured. The correlation between the OCT measurements and the axial length was evaluated. The average, superior, inferior, and nasal RNFL thicknesses of low and moderate myopic eyes were found to be significantly higher than those of highly myopic eyes. The temporal RNFL thicknesses were not different among the three groups. The average, superior, and inferior ganglion cell complex values of low and moderate myopic eyes were significantly higher than those of highly myopic eyes. The FLV and GLV of low and moderate myopic eyes were significantly higher than those of highly myopic eyes (p = 0.001 for all). In the moderate and high myopia groups, the average RNFL thickness and GCC thickness were both negatively correlated with the axial length. Highly myopic subjects tend to have thinner RNFL and GCC thicknesses than subjects with low and moderate myopia.

Nutrition and lifestyle in healthy aging: the telomerase challenge.

PubMed

Boccardi, Virginia; Paolisso, Giuseppe; Mecocci, Patrizia

2016-01-01

Nutrition and lifestyle, known to modulate aging process and age-related diseases, might also affect telomerase activity. Short and dysfunctional telomeres rather than average telomere length are associated with longevity in animal models, and their rescue by telomerase maybe sufficient to restore cell and organismal viability. Improving telomerase activation in stem cells and potentially in other cells by diet and lifestyle interventions may represent an intriguing way to promote health-span in humans.

Improving the efficiency of copper indium gallium (Di-)selenide (CIGS) solar cells through integration of a moth-eye textured resist with a refractive index similar to aluminum doped zinc oxide

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

Burghoorn, M.; Kniknie, B.; Deelen, J. van

2014-12-15

Textured transparent conductors are widely used in thin-film silicon solar cells. They lower the reflectivity at interfaces between different layers in the cell and/or cause an increase in the path length of photons in the Si absorber layer, which both result in an increase in the number of absorbed photons and, consequently, an increase in short-circuit current density (J{sub sc}) and cell efficiency. Through optical simulations, we recently obtained strong indications that texturing of the transparent conductor in copper indium gallium (di-)selenide (CIGS) solar cells is also optically advantageous. Here, we experimentally demonstrate that the J{sub sc} and efficiency ofmore » CIGS solar cells with an absorber layer thickness (d{sub CIGS}) of 0.85 μm, 1.00 μm and 2.00 μm increase through application of a moth-eye textured resist with a refractive index that is sufficiently similar to AZO (n{sub resist} = 1.792 vs. n{sub AZO} = 1.913 at 633 nm) to avoid large optical losses at the resist-AZO interface. On average, J{sub sc} increases by 7.2%, which matches the average reduction in reflection of 7.0%. The average relative increase in efficiency is slightly lower (6.0%). No trend towards a larger relative increase in J{sub sc} with decreasing d{sub CIGS} was observed. Ergo, the increase in J{sub sc} can be fully explained by the reduction in reflection, and we did not observe any increase in J{sub sc} based on an increased photon path length.« less

Traffic-Related Air Pollution and Telomere Length in Children and Adolescents Living in Fresno, CA: A Pilot Study.

PubMed

Lee, Eunice Y; Lin, Jue; Noth, Elizabeth M; Hammond, S Katharine; Nadeau, Kari C; Eisen, Ellen A; Balmes, John R

2017-05-01

The main objective of this pilot study was to gather preliminary information about how telomere length (TL) varies in relation to exposure to polycyclic aromatic hydrocarbons (PAHs) in children living in a highly polluted city. We conducted a cross-sectional study of children living in Fresno, California (n = 14). Subjects with and without asthma were selected based on their annual average PAH level in the 12-months prior to their blood draw. We measured relative telomere length from peripheral blood mononuclear cells (PBMC). We found an inverse linear relationship between average PAH level and TL (R = 0.69), as well as between age and TL (R = 0.21). Asthmatics had shorter mean telomere length than non-asthmatics (TLasthmatic = 1.13, TLnon-asthmatic = 1.29). These preliminary findings suggest that exposure to ambient PAH may play a role in telomere shortening.Become familiar with previous evidence suggesting that telomere length may be a biomarker of air pollution-induced cytotoxicity.Summarize the new findings on the association between polycyclic aromatic hydrocarbon (PAH) exposure and telomere length in adolescents, including those with asthma.Discuss the implications for recommendations and policies to mitigate the health and respiratory effects of traffic-related air pollution.

Reduction of Crosshatch Roughness and Threading Dislocation Density in Metamorphic GaInP Buffers and GaInAs Solar Cells

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

France, R. M.; Geisz, J. F.; Steiner, M. A.

Surface crosshatch roughness typically develops during the growth of lattice-mismatched compositionally graded buffers and can limit misfit dislocation glide. In this study, the crosshatch roughness during growth of a compressive GaInP/GaAs graded buffer is reduced by increasing the phosphine partial pressure throughout the metamorphic growth. Changes in the average misfit dislocation length are qualitatively determined by characterizing the threading defect density and residual strain. The decrease of crosshatch roughness leads to an increase in the average misfit dislocation glide length, indicating that the surface roughness is limiting dislocation glide. Growth rate is also analyzed as a method to reduce surfacemore » crosshatch roughness and increase glide length, but has a more complicated relationship with glide kinetics. Using knowledge gained from these experiments, high quality inverted GaInAs 1 eV solar cells are grown on a GaInP compositionally graded buffer with reduced roughness and threading dislocation density. The open circuit voltage is only 0.38 V lower than the bandgap potential at a short circuit current density of 15 mA/cm{sup 2}, suggesting that there is very little loss due to the lattice mismatch.« less

Nanowire array and nanowire solar cells and methods for forming the same

DOEpatents

Yang, Peidong [Berkeley, CA; Greene, Lori [Berkeley, CA; Law, Matthew [Berkeley, CA

2007-09-04

Homogeneous and dense arrays of nanowires are described. The nanowires can be formed in solution and can have average diameters of 40-300 nm and lengths of 1-3 .mu.m. They can be formed on any suitable substrate. Photovoltaic devices are also described.

Nanowire array and nanowire solar cells and methods for forming the same

DOEpatents

Yang, Peidong; Greene, Lori E.; Law, Matthew

2009-06-09

Homogeneous and dense arrays of nanowires are described. The nanowires can be formed in solution and can have average diameters of 40-300 nm and lengths of 1-3 .mu.m. They can be formed on any suitable substrate. Photovoltaic devices are also described.

The effects of early hypo- and hyperthyroidism on the development of rat cerebellar cortex. III. Kinetics of cell proliferation in the external granular layer.

PubMed

Lauder, J M

1977-04-22

The effects of early hypo- and hyperthyroidism on the rates of cell acquisition and proliferation have been studied in the external granular layer (EGL) of the developing rat cerebellar cortex at 10 days of age using quantitative autoradiographic methods. Both altered thyroid states reduce the rate of cell acquisition in the EGL, but appear to do so for different reasons. Hyperthyroidism shortens the average length of the cell cycle by decreasing the duration of the pre-DNA synthetic phase (G1), indicating that excess thyroxine may exert a direct effect on the EGL. This action involves the early onset of neuronal differentiation (cessation of proliferation)46 which presumably leads to the observed decrease in the rate of cell acquisition (increased doubling time). Such differentiating cells do not, however, leave the proliferative zone or the EGL prematurely, resulting in a reduced labeling index, mitotic index, and growth fraction as non-dividing cells dilute the proliferating cell population. Hypothyroidism, on the other hand, leads to no significant change in the length of the cell cycle or in the mitotic index, but causes a decreased labeling index and growth fraction, as well as a reduced rate of cell acquisition (increased doubling time). No significant change in the amount of cell death in the EGL could be found to explain this apparent discrepancy between the rate of cell proliferation (cell cycle length) and cell acqusiition. The answer to this puzzle appears to lie in the mitotic index, which is not affected to the same extent as the labeling index, although it is also slightly reduced. If cells were to remain longer in mitosis, this could result in a decreased labeling index and growth fraction but nearly normal mitotic index and cell cycle length (as measured using the % labeled mitoses method), since those cells dropping out of the cycling population would be counted as mitoses...

Correlation between the extent of pneumatization of Agger agger Nasi nasi cells and the anterior-to-posterior length of the frontal recess: A a computer-assisted anatomical study.

PubMed

Altıntaş, Ahmet; Çelik, Mustafa; Yegin, Yakup; Canpolat, Sinan; Olgun, Burak; Tülin Kayhan, Fatma

2017-06-30

To explore the correlation between the volume of the aAgger nNasi (AN) cell bulge and the A-P length of the frontal recess (FR). In total, 120 patients, who underwent septoplasty, were included. All patients underwent preoperative paranasal sinus computed tomography of the paranasal sinuses (PNS CT) imaging. In total, CT data on of all 120 PNSs patients were analyzed in terms of thewith respect to the extent of pneumatization of the AN cell bulge and the A-P dimensions of the FR. Each side was analyzed separately. We included 120 patients,: 78 (65.0%) females and 42 (35.0 %) males. Their average age was 33.7 ± 11.6 years (range: 18-65 years). The mean volume of the AN cell bulge was 0.26 ± 0.4 mm3 on both the right and left sides. The A-P length of the FR was 7.7 ± 2.2 mm. No significant between-side difference in the mean volume of the AN cell bulge was apparent observed (p=0.906). This volume did not differ significantly by age or sex (p=0.844 and p=0.971, respectively). We found no correlation between the volume of the AN cell bulge and the A-P length of the FR (r = 0.098, p=0.192). In the present study, no correlation between AN cell volume and the A-P length of the FR was found. When studying the anatomical complexity of the FR, it is essential to consider the AN cell volume. We suggest that preoperative CT imaging is critical when endoscopic sinus surgery is planned. However, further studies with larger numbers of patients are needed to explore the relationship between AN cell pneumatization and the anatomy of the FR.

Effect of heterogeneity on the characterization of cell membrane compartments: I. Uniform size and permeability.

PubMed

Hall, Damien

2010-03-15

Observations of the motion of individual molecules in the membrane of a number of different cell types have led to the suggestion that the outer membrane of many eukaryotic cells may be effectively partitioned into microdomains. A major cause of this suggested partitioning is believed to be due to the direct/indirect association of the cytosolic face of the cell membrane with the cortical cytoskeleton. Such intimate association is thought to introduce effective hydrodynamic barriers into the membrane that are capable of frustrating molecular Brownian motion over distance scales greater than the average size of the compartment. To date, the standard analytical method for deducing compartment characteristics has relied on observing the random walk behavior of a labeled lipid or protein at various temporal frequencies and different total lengths of time. Simple theoretical arguments suggest that the presence of restrictive barriers imparts a characteristic turnover to a plot of mean squared displacement versus sampling period that can be interpreted to yield the average dimensions of the compartment expressed as the respective side lengths of a rectangle. In the following series of articles, we used computer simulation methods to investigate how well the conventional analytical strategy coped with heterogeneity in size, shape, and barrier permeability of the cell membrane compartments. We also explored questions relating to the necessary extent of sampling required (with regard to both the recorded time of a single trajectory and the number of trajectories included in the measurement bin) for faithful representation of the actual distribution of compartment sizes found using the SPT technique. In the current investigation, we turned our attention to the analytical characterization of diffusion through cell membrane compartments having both a uniform size and permeability. For this ideal case, we found that (i) an optimum sampling time interval existed for the analysis and (ii) the total length of time for which a trajectory was recorded was a key factor. Copyright (c) 2009 Elsevier Inc. All rights reserved.

The role of telomere dynamics in aging and cancer

NASA Astrophysics Data System (ADS)

Blagoev, Krastan; Goodwin, Edwin

2006-03-01

Telomere length changes are far more dynamic than previously thought. In addition to a gradual loss of ˜100 base pairs per telomere in each cell division, losses as well as gains may occur within a single cell cycle. We are investigating how telomere exchange, extension, and deletion affect the proliferative potential of telomerase-negative somatic cells. Experimental techniques are being devised to detect dynamic telomere processes and quantify both the frequency and length changes of each. In parallel, a ``dynamic telomere model'' is being used that incorporates telomere dynamics to study how the telomere size distribution evolves with time. This is an essential step towards understanding the role that telomere dynamics play in the normal aging of tissues and organisms. The model casts light on relationships not otherwise easily explained by a deterministic ``mitotic clock,'' or to what extent the shortest initial telomere determines the onset of senescence. We also expect to identify biomarkers that will correlate with aging better than average telomere length and to shed light on the transition to unlimited growth found in telomerase-negative tumor cells having the ALT (alternative lengthening of telomeres) phenotype, and to evaluate strategies to suppress the growth of these tumors.

Telomere length in non-neoplastic gastric mucosa and its relationship to H. pylori infection, degree of gastritis, and NSAID use.

PubMed

Tahara, Tomomitsu; Shibata, Tomoyuki; Kawamura, Tomohiko; Ishizuka, Takamitsu; Okubo, Masaaki; Nagasaka, Mitsuo; Nakagawa, Yoshihito; Arisawa, Tomiyasu; Ohmiya, Naoki; Hirata, Ichiro

2016-02-01

Telomere shortening occurs with human aging in many organs and tissues and is accelerated by rapid cell turnover and oxidative injury. We measured average telomere length using quantitative real-time PCR in non-neoplastic gastric mucosa and assessed its relationship to H. pylori-related gastritis, DNA methylation, ulcer disease, and nonsteroidal anti-inflammatory drug (NSAID) usage. Gastric biopsies were obtained from 151 cancer-free subjects including 49 chronic NSAID users and 102 nonusers. Relative telomere length in genomic DNA was measured by real-time PCR. H. pylori infection status, histological severity of gastritis, and serum pepsinogens (PGs) were also investigated. E-cadherin (CDH1) methylation status was determined by methylation-specific PCR (MSP). Average relative telomere length of H. pylori-infected subjects was significantly shortened when compared to H. pylori-negative subjects (p = 0.002) and was closely associated with all histological parameter of gastritis (all p values <0.01) and CDH1 methylation (p = 0.0002). In H. pylori-negative subjects, NSAID users presented significantly shorter telomere length than nonusers (p = 0.028). Shorter telomere length was observed in duodenal and gastric ulcer patients compared with non-ulcer subjects among NSAID users. Telomere shortening is closely associated with severity of H. pylori-induced gastritis and CDH1 methylation status. Also, telomere shortening is accelerated by NSAID usage especially in H. pylori-negative subjects.

Characterizing emergency admissions of patients with sickle cell crisis in NHS brent: observational study

PubMed Central

Green, Stuart A; AlJuburi, Ghida; Majeed, Azeem; Okoye, Ogo; Amobi, Carole; Banarsee, Ricky; Phekoo, Karen J

2012-01-01

Objectives To characterize emergency admissions for patients with sickle cell crisis in NHS Brent and to determine which patients and practices may benefit most from primary care intervention. Design Observational study Setting Emergency departments attended by residents of the London borough of Brent Participants Patients with sickle cell disease registered with a general practitioner (GP) in the borough of Brent Main outcome measures Analysis of admissions between January 2008 and July 2010 that included length of stay (average and <2 days versus ≥2 days) by age group and registered GP practice. Results Thirty six percent of sickle cell disease admission spells resulted in a length of stay of less than two days. Seventy four percent of total bed days are associated with patients with more than one admission during the period of analysis, i.e. multiple admissions. Two general practices in Brent were identified as having the highest number of patients admitted to the emergency department for sickle cell crisis and may benefit most from primary care intervention. Discussion Patients with short length of stay and multiple admissions may be potentially amenable to primary care intervention. The practices which have the highest numbers of sickle cell disease patients who frequently seek emergency care will be earmarked for an education intervention designed to help further engage general practitioners in the care and management of their sickle cell patients. PMID:22768371

Characterizing emergency admissions of patients with sickle cell crisis in NHS brent: observational study.

PubMed

Green, Stuart A; Aljuburi, Ghida; Majeed, Azeem; Okoye, Ogo; Amobi, Carole; Banarsee, Ricky; Phekoo, Karen J

2012-06-01

To characterize emergency admissions for patients with sickle cell crisis in NHS Brent and to determine which patients and practices may benefit most from primary care intervention. Observational study Emergency departments attended by residents of the London borough of Brent Patients with sickle cell disease registered with a general practitioner (GP) in the borough of Brent Analysis of admissions between January 2008 and July 2010 that included length of stay (average and <2 days versus ≥2 days) by age group and registered GP practice. Thirty six percent of sickle cell disease admission spells resulted in a length of stay of less than two days. Seventy four percent of total bed days are associated with patients with more than one admission during the period of analysis, i.e. multiple admissions. Two general practices in Brent were identified as having the highest number of patients admitted to the emergency department for sickle cell crisis and may benefit most from primary care intervention. Patients with short length of stay and multiple admissions may be potentially amenable to primary care intervention. The practices which have the highest numbers of sickle cell disease patients who frequently seek emergency care will be earmarked for an education intervention designed to help further engage general practitioners in the care and management of their sickle cell patients.

Contraction of gut smooth muscle cells assessed by fluorescence imaging.

PubMed

Tokita, Yohei; Akiho, Hirotada; Nakamura, Kazuhiko; Ihara, Eikichi; Yamamoto, Masahiro

2015-03-01

Here we discuss the development of a novel cell imaging system for the evaluation of smooth muscle cell (SMC) contraction. SMCs were isolated from the circular and longitudinal muscular layers of mouse small intestine by enzymatic digestion. SMCs were stimulated by test agents, thereafter fixed in acrolein. Actin in fixed SMCs was stained with phalloidin and cell length was determined by measuring diameter at the large end of phalloidin-stained strings within the cells. The contractile response was taken as the decrease in the average length of a population of stimulated-SMCs. Various mediators and chemically identified compounds of daikenchuto (DKT), pharmaceutical-grade traditional Japanese prokinetics, were examined. Verification of the integrity of SMC morphology by phalloidin and DAPI staining and semi-automatic measurement of cell length using an imaging analyzer was a reliable method by which to quantify the contractile response. Serotonin, substance P, prostaglandin E2 and histamine induced SMC contraction in concentration-dependent manner. Two components of DKT, hydroxy-α-sanshool and hydroxy-β-sanshool, induced contraction of SMCs. We established a novel cell imaging technique to evaluate SMC contractility. This method may facilitate investigation into SMC activity and its role in gastrointestinal motility, and may assist in the discovery of new prokinetic agents. Copyright © 2015 Japanese Pharmacological Society. Production and hosting by Elsevier B.V. All rights reserved.

Solid-state selective (13)C excitation and spin diffusion NMR to resolve spatial dimensions in plant cell walls.

PubMed

Foston, Marcus; Katahira, Rui; Gjersing, Erica; Davis, Mark F; Ragauskas, Arthur J

2012-02-15

The average spatial dimensions between major biopolymers within the plant cell wall can be resolved using a solid-state NMR technique referred to as a (13)C cross-polarization (CP) SELDOM (selectively by destruction of magnetization) with a mixing time delay for spin diffusion. Selective excitation of specific aromatic lignin carbons indicates that lignin is in close proximity to hemicellulose followed by amorphous and finally crystalline cellulose. (13)C spin diffusion time constants (T(SD)) were extracted using a two-site spin diffusion theory developed for (13)C nuclei under magic angle spinning (MAS) conditions. These time constants were then used to calculate an average lower-limit spin diffusion length between chemical groups within the plant cell wall. The results on untreated (13)C enriched corn stover stem reveal that the lignin carbons are, on average, located at distances ∼0.7-2.0 nm from the carbons in hemicellulose and cellulose, whereas the pretreated material had larger separations.

A Unified Theory for Plants and Plant Structure

NASA Astrophysics Data System (ADS)

Wagner, Orvin E.

1998-04-01

The wave theory provides for quantization of plant structure. If one measures many spacings between plant structures it becomes apparent that certain spacings repeat from plant to plant. These spacings are associated with certain discrete frequencies associated with plant operation. When a branch grows it extend by one or more of discrete half wavelengths associated with permitted frequencies. If conditions are optimum it grows by the larger permitted half wavelengths. The angle that the branch makes with the vertical also determines the length because vertical wave velocities are in general larger than horizontal wave velocities as mentioned in the previous abstract. It also appears that cell dimensions are determined by permitted wavelengths. In conifer fiber cells it appears that there is an exact ratio between the average reciprocals of vertical lengths and horizontal reciprocal averages with a value of 1.50 in the data taken so far. Similar ratios for external structure spacings include 1.50, 1.25, 1.33, 1.66, 3.0, These ratios appear to represent ratios of vertical to horizontal velocities (Wagner 1996). See the Wagner web page.

Picosecond pulse measurements using the active laser medium

NASA Technical Reports Server (NTRS)

Bernardin, James P.; Lawandy, N. M.

1990-01-01

A simple method for measuring the pulse lengths of synchronously pumped dye lasers which does not require the use of an external nonlinear medium, such as a doubling crystal or two-photon fluorescence cell, to autocorrelate the pulses is discussed. The technique involves feeding the laser pulses back into the dye jet, thus correlating the output pulses with the intracavity pulses to obtain pulse length signatures in the resulting time-averaged laser power. Experimental measurements were performed using a rhodamine 6G dye laser pumped by a mode-locked frequency-doubled Nd:YAG laser. The results agree well with numerical computations, and the method proves effective in determining lengths of picosecond laser pulses.

Examining a scaled dynamical system of telomere shortening

NASA Astrophysics Data System (ADS)

Cyrenne, Benoit M.; Gooding, Robert J.

2015-02-01

A model of telomere dynamics is proposed and examined. Our model, which extends a previously introduced model that incorporates stem cells as progenitors of new cells, imposes the Hayflick limit, the maximum number of cell divisions that are possible. This new model leads to cell populations for which the average telomere length is not necessarily a monotonically decreasing function of time, in contrast to previously published models. We provide a phase diagram indicating where such results would be expected via the introduction of scaled populations, rate constants and time. The application of this model to available leukocyte baboon data is discussed.

Identifying the transition to the maturation zone in three ecotypes of Arabidopsis thaliana roots.

PubMed

Cajero Sánchez, Wendy; García-Ponce, Berenice; Sánchez, María de la Paz; Álvarez-Buylla, Elena R; Garay-Arroyo, Adriana

2018-01-01

The Arabidopsis thaliana (hereafter Arabidopsis) root has become a useful model for studying how organ morphogenesis emerge from the coordination and balance of cell proliferation and differentiation, as both processes may be observed and quantified in the root at different stages of development. Hence, being able to objectively identify and delimit the different stages of root development has been very important. Up to now, three different zones along the longitudinal axis of the primary root of Arabidopsis, have been identified: the root apical meristematic zone (RAM) with two domains [the proliferative (PD) and the transition domain (TD)], the elongation zone (EZ) and the maturation zone (MZ). We previously reported a method to quantify the length of the cells of the meristematic and the elongation zone, as well as the boundaries or transitions between the root domains along the growing part of the Arabidopsis root. In this study, we provide a more accurate criterion to identify the MZ. Traditionally, the transition between the EZ to the MZ has been established by the emergence of the first root-hair bulge in the epidermis, because this emergence coincides with cell maturation in this cell type. But we have found here that after the emergence of the first root-hair bulge some cells continue to elongate and we have confirmed this in three different Arabidopsis ecotypes. We established the limit between the EZ and the MZ by looking for the closest cortical cell with a longer length than the average cell length of 10 cells after the cortical cell closest to the epidermal cell with the first root-hair bulge in these three ecotypes. In Col-0 and Ws this cell is four cells above the one with the root hair bulge and, in the Ler ecotype, this cell is five cells above. To unambiguously identifying the site at which cells stop elongating and attain their final length and fate at the MZ, we propose to calculate the length of completely elongated cortical cells counting 10 cells starting from the sixth cell above the cortical cell closest to the epidermal cell with the first root-hair bulge. We validated this proposal in the three ecotypes analyzed and consider that this proposal may aid at having a more objective way to characterize root phenotypes and compare among them.

Identifying the transition to the maturation zone in three ecotypes of Arabidopsis thaliana roots

PubMed Central

Cajero Sánchez, Wendy; García-Ponce, Berenice; Sánchez, María de la Paz; Álvarez-Buylla, Elena R.; Garay-Arroyo, Adriana

2018-01-01

ABSTRACT The Arabidopsis thaliana (hereafter Arabidopsis) root has become a useful model for studying how organ morphogenesis emerge from the coordination and balance of cell proliferation and differentiation, as both processes may be observed and quantified in the root at different stages of development. Hence, being able to objectively identify and delimit the different stages of root development has been very important. Up to now, three different zones along the longitudinal axis of the primary root of Arabidopsis, have been identified: the root apical meristematic zone (RAM) with two domains [the proliferative (PD) and the transition domain (TD)], the elongation zone (EZ) and the maturation zone (MZ). We previously reported a method to quantify the length of the cells of the meristematic and the elongation zone, as well as the boundaries or transitions between the root domains along the growing part of the Arabidopsis root. In this study, we provide a more accurate criterion to identify the MZ. Traditionally, the transition between the EZ to the MZ has been established by the emergence of the first root-hair bulge in the epidermis, because this emergence coincides with cell maturation in this cell type. But we have found here that after the emergence of the first root-hair bulge some cells continue to elongate and we have confirmed this in three different Arabidopsis ecotypes. We established the limit between the EZ and the MZ by looking for the closest cortical cell with a longer length than the average cell length of 10 cells after the cortical cell closest to the epidermal cell with the first root-hair bulge in these three ecotypes. In Col-0 and Ws this cell is four cells above the one with the root hair bulge and, in the Ler ecotype, this cell is five cells above. To unambiguously identifying the site at which cells stop elongating and attain their final length and fate at the MZ, we propose to calculate the length of completely elongated cortical cells counting 10 cells starting from the sixth cell above the cortical cell closest to the epidermal cell with the first root-hair bulge. We validated this proposal in the three ecotypes analyzed and consider that this proposal may aid at having a more objective way to characterize root phenotypes and compare among them. PMID:29497470

Actin kinetics shapes cortical network structure and mechanics

PubMed Central

Fritzsche, Marco; Erlenkämper, Christoph; Moeendarbary, Emad; Charras, Guillaume; Kruse, Karsten

2016-01-01

The actin cortex of animal cells is the main determinant of cellular mechanics. The continuous turnover of cortical actin filaments enables cells to quickly respond to stimuli. Recent work has shown that most of the cortical actin is generated by only two actin nucleators, the Arp2/3 complex and the formin Diaph1. However, our understanding of their interplay, their kinetics, and the length distribution of the filaments that they nucleate within living cells is poor. Such knowledge is necessary for a thorough comprehension of cellular processes and cell mechanics from basic polymer physics principles. We determined cortical assembly rates in living cells by using single-molecule fluorescence imaging in combination with stochastic simulations. We find that formin-nucleated filaments are, on average, 10 times longer than Arp2/3-nucleated filaments. Although formin-generated filaments represent less than 10% of all actin filaments, mechanical measurements indicate that they are important determinants of cortical elasticity. Tuning the activity of actin nucleators to alter filament length distribution may thus be a mechanism allowing cells to adjust their macroscopic mechanical properties to their physiological needs. PMID:27152338

Actin kinetics shapes cortical network structure and mechanics.

PubMed

Fritzsche, Marco; Erlenkämper, Christoph; Moeendarbary, Emad; Charras, Guillaume; Kruse, Karsten

2016-04-01

The actin cortex of animal cells is the main determinant of cellular mechanics. The continuous turnover of cortical actin filaments enables cells to quickly respond to stimuli. Recent work has shown that most of the cortical actin is generated by only two actin nucleators, the Arp2/3 complex and the formin Diaph1. However, our understanding of their interplay, their kinetics, and the length distribution of the filaments that they nucleate within living cells is poor. Such knowledge is necessary for a thorough comprehension of cellular processes and cell mechanics from basic polymer physics principles. We determined cortical assembly rates in living cells by using single-molecule fluorescence imaging in combination with stochastic simulations. We find that formin-nucleated filaments are, on average, 10 times longer than Arp2/3-nucleated filaments. Although formin-generated filaments represent less than 10% of all actin filaments, mechanical measurements indicate that they are important determinants of cortical elasticity. Tuning the activity of actin nucleators to alter filament length distribution may thus be a mechanism allowing cells to adjust their macroscopic mechanical properties to their physiological needs.

Precise mass determination of single cell with cantilever-based microbiosensor system.

PubMed

Łabędź, Bogdan; Wańczyk, Aleksandra; Rajfur, Zenon

2017-01-01

Having determined the mass of a single cell of brewer yeast Saccharomyces cerevisiae by means of a microcantilever-based biosensor Cantisens CSR-801 (Concentris, Basel, Switzerland), it was found that its dry mass is 47,65 ± 1,05 pg. Found to be crucial in this mass determination was the cell position along the length of the cantilever. Moreover, calculations including cells positions on the cantilever provide a threefold better degree of accuracy than those which assume uniform mass distribution. We have also examined the influence of storage time on the single cell mass. Our results show that after 6 months there is an increase in the average mass of a single yeast cell.

78 FR 78503 - Information Collection Activities: Submission for the Office of Management and Budget (OMB...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-26

... landline and/or a personal cell phone. Estimated Number of Respondents--30 pretest respondents, 6,000... a total of 12,460 respondents. Estimated Time per Response--20 minutes per pretest and main survey... survey will be preceded by a pretest administered to 30 respondents. Interview length will average 20...

Diffusing-wave spectroscopy in a standard dynamic light scattering setup

NASA Astrophysics Data System (ADS)

Fahimi, Zahra; Aangenendt, Frank J.; Voudouris, Panayiotis; Mattsson, Johan; Wyss, Hans M.

2017-12-01

Diffusing-wave spectroscopy (DWS) extends dynamic light scattering measurements to samples with strong multiple scattering. DWS treats the transport of photons through turbid samples as a diffusion process, thereby making it possible to extract the dynamics of scatterers from measured correlation functions. The analysis of DWS data requires knowledge of the path length distribution of photons traveling through the sample. While for flat sample cells this path length distribution can be readily calculated and expressed in analytical form; no such expression is available for cylindrical sample cells. DWS measurements have therefore typically relied on dedicated setups that use flat sample cells. Here we show how DWS measurements, in particular DWS-based microrheology measurements, can be performed in standard dynamic light scattering setups that use cylindrical sample cells. To do so we perform simple random-walk simulations that yield numerical predictions of the path length distribution as a function of both the transport mean free path and the detection angle. This information is used in experiments to extract the mean-square displacement of tracer particles in the material, as well as the corresponding frequency-dependent viscoelastic response. An important advantage of our approach is that by performing measurements at different detection angles, the average path length through the sample can be varied. For measurements performed on a single sample cell, this gives access to a wider range of length and time scales than obtained in a conventional DWS setup. Such angle-dependent measurements also offer an important consistency check, as for all detection angles the DWS analysis should yield the same tracer dynamics, even though the respective path length distributions are very different. We validate our approach by performing measurements both on aqueous suspensions of tracer particles and on solidlike gelatin samples, for which we find our DWS-based microrheology data to be in good agreement with rheological measurements performed on the same samples.

Anti-proliferative effects of O-acyl-low-molecular-weight heparin derivatives on bovine pulmonary artery smooth muscle cells.

PubMed

Garg, Hari G; Mrabat, Hicham; Yu, Lunyin; Hales, Charles A; Li, Boyangzi; Moore, Casey N; Zhang, Fuming; Linhardt, Robert J

2011-08-01

Heparin (HP) inhibits the growth of several cell types in vitro including bovine pulmonary artery (BPA) smooth muscle cells (SMCs). In initial studies we discovered that an O-hexanoylated low-molecular-weight (LMW) HP derivative having acyl groups with 6-carbon chain length was more potent inhibitor of BPA-SMCs than the starting HP. We prepared several O-acylated LMWHP derivatives having 4-, 6-, 8-, 10-, 12-, and 18- carbon acyl chain lengths to determine the optimal acyl chain length for maximum anti-proliferative properties of BPA-SMCs. The starting LMWHP was prepared from unfractionated HP by sodium periodate treatment followed by sodium borohydride reduction. The tri-n-butylammonium salt of this LMWHP was O-acylated with butanoic, hexanoic, octanoic, decanoic, dodecanoic, and stearyl anhydrides separately to give respective O-acylated LMWHP derivatives. Gradient polyacrylamide gel electrophoresis (PAGE) was used to examine the average molecular weights of those O-acylated LMWHP derivatives. NMR analysis indicated the presence of one O-acyl group per disaccharide residue. Measurement of the inhibition of BPA-SMCS as a function of O-acyl chain length shows two optima, at a carbon chain length of 6 (O-hexanoylated LMWHP) and at a carbon chain length 12-18 (O-dodecanoyl and O-stearyl LMWHPs). A solution competition SPR study was performed to test the ability of different O-acylated LMWHP derivatives to inhibit fibroblast growth factor (FGF) 1 and FGF2 binding to surface-immobilized heparin. All the LMWHP derivatives bound to FGF1 and FGF2 but each exhibited slightly different binding affinity.

Longer biopsy cores do not increase prostate cancer detection rate: A large-scale cohort study refuting cut-off values indicated in the literature

PubMed Central

Yılmaz, Hasan; Yavuz, Ufuk; Üstüner, Murat; Çiftçi, Seyfettin; Yaşar, Hikmet; Müezzinoğlu, Bahar; Uslubaş, Ali Kemal; Dillioğlugil, Özdal

2017-01-01

Objective Only a few papers in the literature aimed to evaluate biopsy core lengths. Additionally, studies evaluated the core length with different approaches. We aimed to determine whether prostate cancer (PCa) detection is affected from core lengths according to three different approaches in a large standard cohort and compare our cut-off values with the published cut-offs. Material and methods We retrospectively analyzed 1,523 initial consecutive transrectal ultrasound-guided 12-core prostate biopsies. Biopsies were evaluated with respect to total core length (total length of each patients’ core) average core length (total core length divided by total number of cores in each patient), and mean core length (mean length of all cores pooled), and compared our cut-off values with the published cut-offs. The prostate volumes were categorized into four groups (<30, 30–59.99, 60–119.99, ≥120 cm3) and PCa detection rates in these categories were examined. Results PCa was found in 41.5% patients. There was no difference between benign and malignant mean core lengths of the pooled cores (p>0.05). Total core length and average core length were not significantly associated with PCa in multivariate logistic regression analyses (p>0.05). The core lengths (mean, average and total core lengths) increased (p<0.001) and PCa rates decreased (p<0.001) steadily with increasing prostate volume categories. PCa percentages decreased in all categories above the utilized cut-offs for mean (p>0.05), average (p<0.05), and total core lengths (p>0.05). Conclusion There was no difference between mean core lengths of benign and malignant cores. Total core length and average core length were not significantly associated with PCa. Contrary to the cut-offs used for mean and average core lengths in the published studies, PCa rates decrease as these core lengths increase. Larger studies are necessary for the determination and acceptance of accurate cut-offs. PMID:28861301

Quantifying clustered DNA damage induction and repair by gel electrophoresis, electronic imaging and number average length analysis

NASA Technical Reports Server (NTRS)

Sutherland, Betsy M.; Georgakilas, Alexandros G.; Bennett, Paula V.; Laval, Jacques; Sutherland, John C.; Gewirtz, A. M. (Principal Investigator)

2003-01-01

Assessing DNA damage induction, repair and consequences of such damages requires measurement of specific DNA lesions by methods that are independent of biological responses to such lesions. Lesions affecting one DNA strand (altered bases, abasic sites, single strand breaks (SSB)) as well as damages affecting both strands (clustered damages, double strand breaks) can be quantified by direct measurement of DNA using gel electrophoresis, gel imaging and number average length analysis. Damage frequencies as low as a few sites per gigabase pair (10(9)bp) can be quantified by this approach in about 50ng of non-radioactive DNA, and single molecule methods may allow such measurements in DNA from single cells. This review presents the theoretical basis, biochemical requirements and practical aspects of this approach, and shows examples of their applications in identification and quantitation of complex clustered damages.

Different Amounts of DNA in Newborn Cells of Escherichia coli Preclude a Role for the Chromosome in Size Control According to the "Adder" Model.

PubMed

Huls, Peter G; Vischer, Norbert O E; Woldringh, Conrad L

2018-01-01

According to the recently-revived adder model for cell size control, newborn cells of Escherichia coli will grow and divide after having added a constant size or length, ΔL , irrespective of their size at birth. Assuming exponential elongation, this implies that large newborns will divide earlier than small ones. The molecular basis for the constant size increment is still unknown. As DNA replication and cell growth are coordinated, the constant ΔL could be based on duplication of an equal amount of DNA, ΔG , present in newborn cells. To test this idea, we measured amounts of DNA and lengths of nucleoids in DAPI-stained cells growing in batch culture at slow and fast rates. Deeply-constricted cells were divided in two subpopulations of longer and shorter lengths than average; these were considered to represent large and small prospective daughter cells, respectively. While at slow growth, large and small prospective daughter cells contained similar amounts of DNA, fast growing cells with multiforked replicating chromosomes, showed a significantly higher amount of DNA (20%) in the larger cells. This observation precludes the hypothesis that Δ L is based on the synthesis of a constant ΔG . Growth curves were constructed for siblings generated by asymmetric division and growing according to the adder model. Under the assumption that all cells at the same growth rate exhibit the same time between initiation of DNA replication and cell division (i.e., constant C+D -period), the constructions predict that initiation occurs at different sizes ( Li ) and that, at fast growth, large newborn cells transiently contain more DNA than small newborns, in accordance with the observations. Because the state of segregation, measured as the distance between separated nucleoids, was found to be more advanced in larger deeply-constricted cells, we propose that in larger newborns nucleoid separation occurs faster and at a shorter length, allowing them to divide earlier. We propose a composite model in which both differential initiation and segregation leads to an adder-like behavior of large and small newborn cells.

Stimulus-dependent modulation of spike burst length in cat striate cortical cells.

PubMed

DeBusk, B C; DeBruyn, E J; Snider, R K; Kabara, J F; Bonds, A B

1997-07-01

Burst activity, defined by groups of two or more spikes with intervals of < or = 8 ms, was analyzed in responses to drifting sinewave gratings elicited from striate cortical neurons in anesthetized cats. Bursting varied broadly across a population of 507 simple and complex cells. Half of this population had > or = 42% of their spikes contained in bursts. The fraction of spikes in bursts did not vary as a function of average firing rate and was stationary over time. Peaks in the interspike interval histograms were found at both 3-5 ms and 10-30 ms. In many cells the locations of these peaks were independent of firing rate, indicating a quantized control of firing behavior at two different time scales. The activity at the shorter time scale most likely results from intrinsic properties of the cell membrane, and that at the longer scale from recurrent network excitation. Burst frequency (bursts per s) and burst length (spikes per burst) both depended on firing rate. Burst frequency was essentially linear with firing rate, whereas burst length was a nonlinear function of firing rate and was also governed by stimulus orientation. At a given firing rate, burst length was greater for optimal orientations than for nonoptimal orientations. No organized orientation dependence was seen in bursts from lateral geniculate nucleus cells. Activation of cortical contrast gain control at low response amplitudes resulted in no burst length modulation, but burst shortening at optimal orientations was found in responses characterized by supersaturation. At a given firing rate, cortical burst length was shortened by microinjection of gamma-aminobutyric acid (GABA), and bursts became longer in the presence of N-methyl-bicuculline, a GABA(A) receptor blocker. These results are consistent with a model in which responses are reduced at nonoptimal orientations, at least in part, by burst shortening that is mediated by GABA. A similar mechanism contributes to response supersaturation at high contrasts via recruitment of inhibitory responses that are tuned to adjacent orientations. Burst length modulation can serve as a form of coding by supporting dynamic, stimulus-dependent reorganization of the effectiveness of individual network connections.

Mesh wrapping for severe hepatic injury: a beneficial option in the trauma surgeon's armamentarium.

PubMed

Kennedy, Ryan; Brevard, Sidney B; Bosarge, Patrick; Simmons, Jon D; Frotan, Mohammed A; Baker, Jeremy A; Tuart, Lynda; Pritchett, Cindy; Gonzalez, Richard P

2015-03-01

The purpose of this study was to assess the efficacy of absorbable mesh wrapping (MW) versus perihepatic packing (HP) for severe hepatic injury. From January 2001 to December 2012, data were collected for MW patients with hepatic injury. Patients who underwent HP were matched with MW patients by injury mechanism, liver injury grade, Injury Severity Score, and age. Twenty-six MW and twenty-six HP patients were matched. Eighteen blunt and 8 penetrating injuries were present in each group. There were 9 (35%) mortalities in the MW group and 16 (62%) in the HP groups (P = .03). Average transfusions were 12.0 and 24.5 (P = .03) packed red blood cells in the MW and HP groups, respectively. Average laparotomies per survivors were 1.3 for the MW and 3.1 for the HP groups (P = .01). Average length of stay for survivors was 19 and 47 (P = .04) days in the MW and HP groups, respectively. MW for hepatic injuries can significantly decrease mortality, transfusions, laparotomies, and length of stay. Copyright © 2015 Elsevier Inc. All rights reserved.

[The effect of acupuncture and endogenous c-Fos, c-Jun on regeneration of neuronal dendrite of spared DRG in vitro following partial ganglionectomy].

PubMed

Wang, Te-wei; Wang, Ting-hua; Zhou, Xue; Zhang, Lian-shuang; Xu, Xin-yun

2007-09-01

To explore the effect of acupuncture, endogenous c-Fos and c-Jun on the regeneration of neuronal dendrite of spared dorsal root ganglion (DRG) in vitro following partial ganglionectomy. Five adult male cats were used in this experiment. Their bilateral L1-L5, L7-S2 DRG were removed, and L6 DRG were spared. Then unilaterally, two sets of acupoints (Zusanli(St. 36) and Xuanzhong(G. B. 39); Futu (St. 32) and Sanyinjiao (Sp. 6) located in the distribution area of spinal nerve L6) were electro-stimulated alternately 30 min everyday by electro-needling. Seven days after operation, bilateral L6 DRGs were taken out and were cultured respectively in vitro. Some cultured mediums of the acupuncture lateral wells were totally replaced by each corresponding antibody-cultured medium including respectively 100 ng/mL anti-c-Fos and anti-c-Jun antibody at the 24th hour and terminated after 7 days. The length of the neurite was measured by upside-down light microscopy. Then, cultured cells were stained by the immunohistochemistry ABC method. Data were analyzed by One-way ANOVA and q test. Immunocytochemical staining revealed that over 95% cells were NSE positive cells which were the typical neuron of DRG in vitro. On the 7th day, the average neurite length of the spared DRG group, the anti-c-Fos antibody and the anti-c-Jun antibody group were shorter than that of the acupuncture group (P < 0.05); the average neurite length of the two antibody groups were longer than that of the spared DRG group (P < 0.05). These results indicate that acupuncture, endogenous c-Fos and c-Jun probably promote regeneration of neuronal dendrite of spared DRG in vitro.

[The impacts of the multidisciplinary team model on the length of stay and hospital expenses of patients with lung cancer].

PubMed

Zou, Jing; Xu, Xingxiang; Wang, Daxin; Xu, Jin; Gu, Wenju

2015-05-01

To explore the impacts of the multidisciplinary team model on the average length of stay and hospital expenses of patients with lung cancer. After the multidisciplinary team discussion, 97 patients with lung cancer were selected as the lung cancer group according to the enrollment and elimination criteria the control group was 97 patients with lung cancer managed without team discussion during the same period. All the patients were firstly diagnosed to have lung cancer from December 2011 to December 2013 in Subei People's Hospital. The length of stay, hospital expenses, stages of tumor, types of tumor, Zubrod-ECOG-WHO score, the form of payment, smoking history, sex and age of all the patients were collected. The difference in the average length of stay and hospital expenses between the 2 groups and the associated factors were analyzed by using χ² test, t test and multi-factor stepwise regression analysis. There were 68 males and 29 females with a mean age of (61 ± 9) years in the lung cancer group, while there were 73 males and 24 females with a mean age of (63 ± 10) years in the control group. There were no differences between the 2 groups in tumor staging, tumor types, Zubrod-ECOG-WHO score, the form of payment, smoking history, sex and age (χ² = 4.854, P = 0.563, χ² = 4.248, P = 0.097; χ² = 0.395, P = 0.821; χ² = 1.191, P = 0.554; χ² = 0.108, P = 0.977; χ² = 1.011, P = 0.389; χ² = 0.649, P = 0.519; P = 0.474, P = 0.845, respectively). The average hospital expenses (13 303 vs 16 553, Yuan) were lower and the length of stay (10.33 vs 12.49, days) was shorter in the lung cancer group as compared to the control group (t = 2.616, P = 0.010; t = 2.730, P = 0.007), especially so for the first clinical hospitalization (15 953 vs 19 485 yuan, t = 2.315, P = 0.022; 12.71 vs 14.75 days, t = 1.979, P = 0.049). The average length of stay and the tumor stages were the main factors associated with the average hospital expenses. Except for patients with the limited stage of small cell lung cancer, the average length of stay and hospital expenses showed a tendency to reduce in different stages of the lung cancer group. The hospital cost was lower and the length of stay shorter for patients with stages Ia-IIIa and IIIb-IV in the lung cancer group as compared to the control group (6 722 vs 8 188 yuan; 1.09 vs 2.65 days). The multidisciplinary team model was an effective measure to cut down the hospital expenses and shorten the length of stay of lung cancer patients, especially for the first hospitalization. Patients may benefit from the multidisciplinary team approach according to their stages. On the basis of reducing the hospital costs and the length of stay, it further reduced the gap of the length of stay and hospital expenses between patients with Ia-IIIa and IIIb-IV diseases, while patients with stage Ia-IIIa disease seemed to benefit more.

Theoretical description of transverse measurements of polarization in optically-pumped Rb vapor cells

NASA Astrophysics Data System (ADS)

Dreiling, Joan; Tupa, Dale; Norrgard, Eric; Gay, Timothy

2012-06-01

In optical pumping of alkali-metal vapors, the polarization of the atoms is typically determined by probing along the entire length of the pumping beam, resulting in an averaged value of polarization over the length of the cell. Such measurements do not give any information about spatial variations of the polarization along the pump beam axis. Using a D1 probe beam oriented perpendicular to the pumping beam, we have demonstrated a heuristic method for determining the polarization along the pump beam's axis. Adapting a previously developed theory [1], we provide an analysis of the experiment which explains why this method works. The model includes the effects of Rb density, buffer gas pressure, and pump detuning. [4pt] [1] E.B. Norrgard, D. Tupa, J.M. Dreiling, and T.J. Gay, Phys. Rev. A 82, 033408 (2010).

The relationship between type of telephone service and smoking cessation among rural smokers enrolled in quitline tobacco dependence treatment.

PubMed

Nemeth, Julianna M; Cooper, Sarah; Wermert, Amy; Shoben, Abigail; Wewers, Mary Ellen

2017-12-01

Quitlines are successful tools for smoking cessation, but no known study has examined whether type of phone service (cell phone only (CPO) vs. landline (LL)) impacts quitline utilization, quit attempts, and sustained cessation. This report details an observational study examining the association between phone service and quitline utilization and cessation among Ohio Appalachian adults willing to quit smoking and enrolled in a cessation trial from 2010 to 2014. A secondary analysis was conducted with data obtained from smokers enrolled in the Ohio Tobacco Quitline arm of a group randomized trial (n = 345). The intermediate outcome variables included number of calls, cumulative total call length, average call length, verified shipments of NRT, and 24-hour quit attempt. The primary outcome measure was biologically confirmed 7-day point prevalence abstinence from tobacco at 3, 6, and 12 months post treatment. Participants with LL service, on average, made almost one more call to the quitline and spoke 17.2 min longer over the course of treatment than those with CPO service. Those with LL service were more likely to receive a second 4-week supply of NRT. Phone service status was not associated with average quitline call length, receiving at least one NRT shipment, having made one quit attempt at the end of treatment, or biochemically confirmed abstinence at 3, 6, or 12-month follow-up. Participants with LL services completed more counseling calls, accrued a longer cumulative length, and received more NRT when compared with CPO service participants. However, type of phone service did not deter abstinence outcomes.

Rugate filter for light-trapping in solar cells.

PubMed

Fahr, Stephan; Ulbrich, Carolin; Kirchartz, Thomas; Rau, Uwe; Rockstuhl, Carsten; Lederer, Falk

2008-06-23

We suggest a design for a coating that could be applied on top of any solar cell having at least one diffusing surface. This coating acts as an angle and wavelength selective filter, which increases the average path length and absorptance at long wavelengths without altering the solar cell performance at short wavelengths. The filter design is based on a continuous variation of the refractive index in order to minimize undesired reflection losses. Numerical procedures are used to optimize the filter for a 10 microm thick monocrystalline silicon solar cell, which lifts the efficiency above the Auger limit for unconcentrated illumination. The feasibility to fabricate such filters is also discussed, considering a finite available refractive index range.

Childhood adversity, social support, and telomere length among perinatal women.

PubMed

Mitchell, Amanda M; Kowalsky, Jennifer M; Epel, Elissa S; Lin, Jue; Christian, Lisa M

2018-01-01

Adverse perinatal health outcomes are heightened among women with psychosocial risk factors, including childhood adversity and a lack of social support. Biological aging could be one pathway by which such outcomes occur. However, data examining links between psychosocial factors and indicators of biological aging among perinatal women are limited. The current study examined the associations of childhood socioeconomic status (SES), childhood trauma, and current social support with telomere length in peripheral blood mononuclear cells (PBMCs) in a sample of 81 women assessed in early, mid, and late pregnancy as well as 7-11 weeks postpartum. Childhood SES was defined as perceived childhood social class and parental educational attainment. Measures included the Childhood Trauma Questionnaire, Center for Epidemiologic Studies-Depression Scale, Multidimensional Scale of Perceived Social Support, and average telomere length in PBMCs. Per a linear mixed model, telomere length did not change across pregnancy and postpartum visits; thus, subsequent analyses defined telomere length as the average across all available timepoints. ANCOVAs showed group differences by perceived childhood social class, maternal and paternal educational attainment, and current family social support, with lower values corresponding with shorter telomeres, after adjustment for possible confounds. No effects of childhood trauma or social support from significant others or friends on telomere length were observed. Findings demonstrate that while current SES was not related to telomeres, low childhood SES, independent of current SES, and low family social support were distinct risk factors for cellular aging in women. These data have relevance for understanding potential mechanisms by which early life deprivation of socioeconomic and relationship resources affect maternal health. In turn, this has potential significance for intergenerational transmission of telomere length. The predictive value of markers of biological versus chronological age on birth outcomes warrants investigation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Average focal length and power of a section of any defined surface.

PubMed

Kaye, Stephen B

2010-04-01

To provide a method to allow calculation of the average focal length and power of a lens through a specified meridian of any defined surface, not limited to the paraxial approximations. University of Liverpool, Liverpool, United Kingdom. Functions were derived to model back-vertex focal length and representative power through a meridian containing any defined surface. Average back-vertex focal length was based on the definition of the average of a function, using the angle of incidence as an independent variable. Univariate functions allowed determination of average focal length and power through a section of any defined or topographically measured surface of a known refractive index. These functions incorporated aberrations confined to the section. The proposed method closely approximates the average focal length, and by inference power, of a section (meridian) of a surface to a single or scalar value. It is not dependent on the paraxial and other nonconstant approximations and includes aberrations confined to that meridian. A generalization of this method to include all orthogonal and oblique meridians is needed before a comparison with measured wavefront values can be made. Copyright (c) 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Some structural features of the teichuronic acid of Bacillus licheniformis N.C.T.C. 6346 cell walls

PubMed Central

Hughes, R. C.; Thurman, P. F.

1970-01-01

A teichuronic acid, containing glucuronic acid and N-acetylgalactosamine, was purified from acid extracts of Bacillus licheniformis 6346 cell walls as described by Janczura, Perkins & Rogers (1961). After reduction of the carboxyl function of glucuronic acid residues in the polysaccharide the reduced polymer contains equimolar amounts of N-acetylgalactosamine and glucose. Methylation of the reduced polysaccharide by the Hakamori (1964) technique showed the glucose residues to be substituted on C-4. A disaccharide, 3-O-glucuronosylgalactosamine, was isolated from partial acid hydrolysates of teichuronic acid. After N-acetylation the disaccharide produces chromogen readily on heating at pH7, in agreement with C-3 substitution of the reducing N-acetylamino sugar. Teichuronic acid also produces chromogen under the same conditions, with concurrent elimination of a modified polysaccharide from C-3 of reducing terminal N-acetylgalactosamine residues of the teichuronic acid chains. The number-average chain lengths of several preparations of teichuronic acid were estimated from the amounts of chromogen produced in comparison with the N-acetylated disaccharide. The values obtained are in good agreement with the weight-average molecular weight determined by ultracentrifugal analysis. The reducing terminals of teichuronic acid are shown to be exclusively N-acetylgalactosamine by reduction with sodium boro[3H]hydride. The number-average chain lengths of the teichuronic acid preparations were estimated by the extent of in corporation of tritium and are in agreement with values obtained by the other methods. PMID:5419741

Orientation and length of mammalian skeletal myocytes in response to a unidirectional stretch

NASA Technical Reports Server (NTRS)

Collinsworth, A. M.; Torgan, C. E.; Nagda, S. N.; Rajalingam, R. J.; Kraus, W. E.; Truskey, G. A.

2000-01-01

Effects of mechanical forces exerted on mammalian skeletal muscle cells during development were studied using an in vitro model to unidirectionally stretch cultured C2C12 cells grown on silastic membrane. Previous models to date have not studied these responses of the mammalian system specifically. The silastic membrane upon which these cells were grown exhibited linear strain behavior over the range of 3.6-14.6% strain, with a Poisson's ratio of approximately 0.5. To mimic murine in utero long bone growth, cell substrates were stretched at an average strain rate of 2.36%/day for 4 days or 1.77%/day for 6 days with an overall membrane strain of 9.5% and 10.6%, respectively. Both control and stretched fibers stained positively for the contractile protein, alpha-actinin, demonstrating muscle fiber development. An effect of stretch on orientation and length of myofibers was observed. At both strain rates, stretched fibers aligned at a smaller angle relative to the direction of stretch and were significantly longer compared to randomly oriented control fibers. There was no effect of duration of stretch on orientation or length, suggesting the cellular responses are independent of strain rate for the range tested. These results demonstrate that, under conditions simulating mammalian long bone growth, cultured myocytes respond to mechanical forces by lengthening and orienting along the direction of stretch.

Calcium dependent formation of tubular assemblies by recombinant S-layer proteins in vivo and in vitro

NASA Astrophysics Data System (ADS)

Korkmaz, Nuriye; Ostermann, Kai; Rödel, Gerhard

2011-03-01

Surface layer proteins have the appealing property to self-assemble in nanosized arrays in solution and on solid substrates. In this work, we characterize the formation of assembly structures of the recombinant surface layer protein SbsC of Geobacillus stearothermophilus ATTC 12980, which was tagged with enhanced green fluorescent protein and expressed in the yeast Saccharomyces cerevisiae. The tubular structures formed by the protein in vivo are retained upon bursting the cells by osmotic shock; however, their average length is decreased. During dialysis, monomers obtained by treatment with chaotropic chemicals recrystallize again to form tube-like structures. This process is strictly dependent on calcium (Ca2 + ) ions, with an optimal concentration of 10 mM. Further increase of the Ca2 + concentration results in multiple non-productive nucleation points. We further show that the lengths of the S-layer assemblies increase with time and can be controlled by pH. After 48 h, the average length at pH 9.0 is 4.13 µm compared to 2.69 µm at pH 5.5. Successful chemical deposition of platinum indicates the potential of recrystallized mSbsC-eGFP structures for nanobiotechnological applications.

Local homogeneity of cell cycle length in developing mouse cortex

NASA Technical Reports Server (NTRS)

Cai, L.; Hayes, N. L.; Nowakowski, R. S.

1997-01-01

We have measured the amount of variation in the length of the cell cycle for cells in the pseudostratified ventricular epithelium (PVE) of the developing cortex of mice on embryonic day 14. Our measurements were made in three cortical regions (i.e., the neocortex, archicortex, and periarchicortex) using three different methods: the cumulative labeling method (CLM), the percent labeled mitoses (PLM) method, and a comparison of the time needed for the PLM to ascend from 0 to 100% with the time needed for the PLM to descend from 100 to 0%. These 3 different techniques provide different perspectives on the cytokinetic parameters. Theoretically, CLM gives an estimate for a maximum value of the total length of the cell cycle (TC), whereas PLM gives an estimate of a minimum value of TC. The difference between these two estimates indicates that the range for TC is +/-1% of the mean TC for periarchicortex, +/-7% for neocortex, and +/-8% for archicortex. This was confirmed by a lengthening of the PLM descent time in comparison with its ascent time. The sharpness of the transitions and the flatness of the plateau of the PLM curves indicate that 99% of the proliferating cells are within this narrow estimated range for TC; hence, only approximately 1% deviate outside of a relatively restricted range from the average TC of the population. In the context of the possible existence within the cortical PVE of two populations with markedly dissimilar cell cycle kinetics from the mean, one such population must comprise approximately 99% of the total population, and the other, if it exists, is only approximately 1% of the total. This seems to be true for all three cortical regions. The narrow range of TC indicates a homogeneity in the cell cycle length for proliferating cells in three different cortical regions, despite the fact that progenitor cells of different lineages may be present. It further predicts the existence of almost synchronous interkinetic nuclear movements of the proliferating cells in the ventricular zone during early development of the cerebral cortex.

Does endothelial cell density correlate with corneal diameter in a group of young adults?

PubMed

Giasson, Claude J; Gosselin, Lucie; Masella, Aviva; Forcier, Pierre

2008-07-01

In children, but not in the elderly, an association exists between corneal diameter and endothelial cell density (ECD). We tested whether such an association also held true in young adults. The eyes of 35 healthy subjects (mean age, 23.1 +/- 3.1 years) were photographed by using a video camera and a noncontact endothelial microscope. Both sets of images were analyzed with image software and the contour method to measure corneal diameter, ECD, and endothelial coefficients. Axial lengths, refractive errors, and corneal curvatures were measured by using an A-scan ultrasonic biometer and kerato-refractometer. Measurements, averaged for the right and left eyes, were analyzed depending on (1) use of contact lenses, (2) ametropia, and on whether (3) axial length or (4) corneal diameter was above or below group means. Differences were tested for statistical significance with independent t tests and association with the Pearson correlation coefficient. ECD, corneal diameter, and spherical equivalent refraction were 3022 +/- 262 cells/mm2, 12.0 +/- 0.5 mm, and -3.1 +/- 2.5 D, respectively. The only significant differences between wearers and nonwearers of contact lenses were the spherical refractive equivalent and axial length. There was no correlation between ECD and corneal diameter or axial length. As opposed to previously reported results in children, but as found in the elderly, there is no correlation between ECD and corneal diameter in young adults. Therefore, corneal size cannot be considered a determinant of ECD in young adults.

Ganglion cell-inner plexiform layer and retinal nerve fiber layer thickness according to myopia and optic disc area: a quantitative and three-dimensional analysis.

PubMed

Seo, Sam; Lee, Chong Eun; Jeong, Jae Hoon; Park, Ki Ho; Kim, Dong Myung; Jeoung, Jin Wook

2017-03-11

To determine the influences of myopia and optic disc size on ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (RNFL) thickness profiles obtained by spectral domain optical coherence tomography (OCT). One hundred and sixty-eight eyes of 168 young myopic subjects were recruited and assigned to one of three groups according to their spherical equivalent (SE) values and optic disc area. All underwent Cirrus HD-OCT imaging. The influences of myopia and optic disc size on the GCIPL and RNFL thickness profiles were evaluated by multiple comparisons and linear regression analysis. Three-dimensional surface plots of GCIPL and RNFL thickness corresponding to different combinations of myopia and optic disc size were constructed. Each of the quadrant RNFL thicknesses and their overall average were significantly thinner in high myopia compared to low myopia, except for the temporal quadrant (all Ps ≤0.003). The average and all-sectors GCIPL were significantly thinner in high myopia than in moderate- and/or low-myopia (all Ps ≤0.002). The average OCT RNFL thickness was correlated significantly with SE (0.81 μm/diopter, P < 0.001), axial length (-1.44 μm/mm, P < 0.001), and optic disc area (5.35 μm/mm 2 , P < 0.001) by linear regression analysis. As for the OCT GCIPL parameters, average GCIPL thickness showed a significant correlation with SE (0.84 μm/diopter, P < 0.001) and axial length (-1.65 μm/mm, P < 0.001). There was no significant correlation of average GCIPL thickness with optic disc area. Three-dimensional curves showed that larger optic discs were associated with increased average RNFL thickness and that more-myopic eyes were associated with decreased average GCIPL and RNFL thickness. Myopia can significantly affect GCIPL and RNFL thickness profiles, and optic disc size has a significant influence on RNFL thickness. The current OCT maps employed in the evaluation of glaucoma should be analyzed in consideration of refractive status and optic disc size.

Can Meristematic Activity Determine Variation in Leaf Size and Elongation Rate among Four Poa Species? A Kinematic Study1

PubMed Central

Fiorani, Fabio; Beemster, Gerrit T.S.; Bultynck, Lieve; Lambers, Hans

2000-01-01

We studied inherent variation in final leaf size among four Poa spp. that live at different elevations. The average final length of leaf 7 of the main stem of the smallest species (Poa alpina) was only one-half that of the largest species (Poa trivialis); it was correlated with leaf elongation rate, but not with the duration of leaf elongation. A faster rate of leaf elongation rate was associated with (a) larger size of the zone of cell expansion, and (b) faster rates of cell production (per cell file) in the meristem, which in turn were due to greater numbers of dividing cells, whereas average cell division rates were very similar for all species (except Poa annua). Also we found that the proliferative fraction equaled 1 throughout the meristem in all species. It was remarkable that rates of cell expansion tended to be somewhat higher in the species with slower growing leaves. We discuss the results by comparing the spatial and material viewpoints, which lead to different interpretations of the role of cell division. Although the presented data do not strictly prove it, they strongly suggest a regulatory role for cell division in determining differences in growth rate among the present four Poa spp. PMID:11027732

The influence of magnetic fields exposure on neurite outgrowth in PC12 rat pheochromocytoma cells

NASA Astrophysics Data System (ADS)

Fan, W.; Ding, J.; Duan, W.; Zhu, Y. M.

2004-11-01

The aim of present work was to investigate the influence of magnetic fields exposure on neurite outgrowth in PC12 cells. The neurite number per cell, length of neurites and directions of neurite growth with respect to the direction of the magnetic field were analyzed after exposure to 50 Hz electromagnetic field for 96 h. A promotion was observed under a weak field (0.23 mT), as the average number of neurites per cell increased to 2.38±0.06 compared to 1.91±0.07 neurites/cell of the control dishes, while inhibition and directional outgrowth was evident under a relatively stronger field (1.32 mT). Our work shows that biological systems can be very sensitive to the strength of electromagnetic field.

Correlation between spectral-domain OCT findings and visual acuity in X-linked retinoschisis.

PubMed

Yang, Hyun Seung; Lee, Jung Bok; Yoon, Young Hee; Lee, Joo Yong

2014-05-08

To investigate the tomographic characteristics of the outer retina and choroid and their relationship with visual acuity in X-linked juvenile retinoschisis (XLRS) patients using spectral-domain optical coherence tomography (SD-OCT). In this retrospective, observational, case-control study, we analyzed 20 eyes of 10 patients with XLRS using SD-OCT. The clinical and tomographic features of the outer retina, including the external limiting membrane (ELM), inner segment/outer segment (IS/OS) junction, cone cell outer segment tips (COST) line, photoreceptor outer segment (PROS) length, and choroid, were evaluated. As controls, 40 age-, sex-, and refraction-matched healthy eyes (1:2 matched) were randomly selected and imaged in parallel. The most prevalent area of abnormality in the outer retina layer of our patients was the outer plexiform layer (OPL; 60% of all affected eyes) and COST line (75% of all affected eyes). On average, the subfoveal choroid and PROS lengths were 35 μm thicker and 19 μm thinner, respectively, in XLRS patients (P = 0.084 and P < 0.001, respectively). A dominant IS/OS junction, COST line defects, and PROS length were related to patient best-corrected visual acuity (BCVA; P = 0.029, P = 0.001, and P < 0.001, respectively) by univariate analysis. Cone cell outer segment tips line defect and PROS length were the only factors related to BCVA in multivariate analysis (P = 0.028 and 0.003, respectively). Outer plexiform layer and photoreceptor microstructure defects are frequent in XLRS patients. Cone cell outer segment tips line defects and shortened PROS lengths as well as other photoreceptor microstructure defects may be closely related to poor vision in XLRS.

The Distribution of Lightning Channel Lengths in Northern Alabama Thunderstorms

NASA Technical Reports Server (NTRS)

Peterson, H. S.; Koshak, W. J.

2010-01-01

Lightning is well known to be a major source of tropospheric NOx, and in most cases is the dominant natural source (Huntreiser et al 1998, Jourdain and Hauglustaine 2001). Production of NOx by a segment of a lightning channel is a function of channel segment energy density and channel segment altitude. A first estimate of NOx production by a lightning flash can be found by multiplying production per segment [typically 104 J/m; Hill (1979)] by the total length of the flash s channel. The purpose of this study is to determine average channel length for lightning flashes near NALMA in 2008, and to compare average channel length of ground flashes to the average channel length of cloud flashes.

Interrogating the Escherichia coli cell cycle by cell dimension perturbations

PubMed Central

Zheng, Hai; Ho, Po-Yi; Jiang, Meiling; Tang, Bin; Liu, Weirong; Li, Dengjin; Yu, Xuefeng; Kleckner, Nancy E.; Amir, Ariel; Liu, Chenli

2016-01-01

Bacteria tightly regulate and coordinate the various events in their cell cycles to duplicate themselves accurately and to control their cell sizes. Growth of Escherichia coli, in particular, follows a relation known as Schaechter’s growth law. This law says that the average cell volume scales exponentially with growth rate, with a scaling exponent equal to the time from initiation of a round of DNA replication to the cell division at which the corresponding sister chromosomes segregate. Here, we sought to test the robustness of the growth law to systematic perturbations in cell dimensions achieved by varying the expression levels of mreB and ftsZ. We found that decreasing the mreB level resulted in increased cell width, with little change in cell length, whereas decreasing the ftsZ level resulted in increased cell length. Furthermore, the time from replication termination to cell division increased with the perturbed dimension in both cases. Moreover, the growth law remained valid over a range of growth conditions and dimension perturbations. The growth law can be quantitatively interpreted as a consequence of a tight coupling of cell division to replication initiation. Thus, its robustness to perturbations in cell dimensions strongly supports models in which the timing of replication initiation governs that of cell division, and cell volume is the key phenomenological variable governing the timing of replication initiation. These conclusions are discussed in the context of our recently proposed “adder-per-origin” model, in which cells add a constant volume per origin between initiations and divide a constant time after initiation. PMID:27956612

Interrogating the Escherichia coli cell cycle by cell dimension perturbations.

PubMed

Zheng, Hai; Ho, Po-Yi; Jiang, Meiling; Tang, Bin; Liu, Weirong; Li, Dengjin; Yu, Xuefeng; Kleckner, Nancy E; Amir, Ariel; Liu, Chenli

2016-12-27

Bacteria tightly regulate and coordinate the various events in their cell cycles to duplicate themselves accurately and to control their cell sizes. Growth of Escherichia coli, in particular, follows a relation known as Schaechter's growth law. This law says that the average cell volume scales exponentially with growth rate, with a scaling exponent equal to the time from initiation of a round of DNA replication to the cell division at which the corresponding sister chromosomes segregate. Here, we sought to test the robustness of the growth law to systematic perturbations in cell dimensions achieved by varying the expression levels of mreB and ftsZ We found that decreasing the mreB level resulted in increased cell width, with little change in cell length, whereas decreasing the ftsZ level resulted in increased cell length. Furthermore, the time from replication termination to cell division increased with the perturbed dimension in both cases. Moreover, the growth law remained valid over a range of growth conditions and dimension perturbations. The growth law can be quantitatively interpreted as a consequence of a tight coupling of cell division to replication initiation. Thus, its robustness to perturbations in cell dimensions strongly supports models in which the timing of replication initiation governs that of cell division, and cell volume is the key phenomenological variable governing the timing of replication initiation. These conclusions are discussed in the context of our recently proposed "adder-per-origin" model, in which cells add a constant volume per origin between initiations and divide a constant time after initiation.

Overexpression of OsEXPA8, a Root-Specific Gene, Improves Rice Growth and Root System Architecture by Facilitating Cell Extension

PubMed Central

Ma, Nana; Wang, Ying; Qiu, Shichun; Kang, Zhenhui; Che, Shugang; Wang, Guixue; Huang, Junli

2013-01-01

Expansins are unique plant cell wall proteins that are involved in cell wall modifications underlying many plant developmental processes. In this work, we investigated the possible biological role of the root-specific α-expansin gene OsEXPA8 in rice growth and development by generating transgenic plants. Overexpression of OsEXPA8 in rice plants yielded pleiotropic phenotypes of improved root system architecture (longer primary roots, more lateral roots and root hairs), increased plant height, enhanced leaf number and enlarged leaf size. Further study indicated that the average cell length in both leaf and root vascular bundles was enhanced, and the cell growth in suspension cultures was increased, which revealed the cellular basis for OsEXPA8-mediated rice plant growth acceleration. Expansins are thought to be a key factor required for cell enlargement and wall loosening. Atomic force microscopy (AFM) technology revealed that average wall stiffness values for 35S::OsEXPA8 transgenic suspension-cultured cells decreased over six-fold compared to wild-type counterparts during different growth phases. Moreover, a prominent change in the wall polymer composition of suspension cells was observed, and Fourier-transform infrared (FTIR) spectra revealed a relative increase in the ratios of the polysaccharide/lignin content in cell wall compositions of OsEXPA8 overexpressors. These results support a role for expansins in cell expansion and plant growth. PMID:24124527

Dynamics of F-actin prefigure the structure of butterfly wing scales.

PubMed

Dinwiddie, April; Null, Ryan; Pizzano, Maria; Chuong, Lisa; Leigh Krup, Alexis; Ee Tan, Hwei; Patel, Nipam H

2014-08-15

The wings of butterflies and moths consist of dorsal and ventral epidermal surfaces that give rise to overlapping layers of scales and hairs (Lepidoptera, "scale wing"). Wing scales (average length ~200 µm) are homologous to insect bristles (macrochaetes), and their colors create the patterns that characterize lepidopteran wings. The topology and surface sculpture of wing scales vary widely, and this architectural complexity arises from variations in the developmental program of the individual scale cells of the wing epithelium. One of the more striking features of lepidopteran wing scales are the longitudinal ridges that run the length of the mature (dead) cell, gathering the cuticularized scale cell surface into pleats on the sides of each scale. While also present around the periphery of other insect bristles and hairs, longitudinal ridges in lepidopteran wing scales gain new significance for their creation of iridescent color through microribs and lamellae. Here we show the dynamics of the highly organized F-actin filaments during scale cell development, and present experimental manipulations of actin polymerization that reveal the essential role of this cytoskeletal component in wing scale elongation and the positioning of longitudinal ribs. Copyright © 2014 Elsevier Inc. All rights reserved.

Modeling of hyaluronic acid containing anti-cancer drugs-loaded polylactic-co-glycolic acid bioconjugates for targeted delivery to cancer cells

NASA Astrophysics Data System (ADS)

Gul-e-Saba, Adulphakdee, A.; Madthing, A.; Zafar, M. N.; Abdullah, M. A.

2012-09-01

Molecular modeling of hyaluronan (HA), polylactic-co-glycolic acid (PLGA), polyethylene glycol-bis-amine (PEG-bis-amine), Curcumin, Cisplatin and the conjugate HA-PEG-PLGA containing Curcumin/Cisplatin were performed using Discovery Studio 2.5 to better understand issues and constraints related to targeted delivery of potent anticancer drugs to cancer cells. HA, a versatile biopolymer is a ligand of cancer cell receptor, CD44 that can be particularly useful in a receptor-mediated cellular uptake of drug-incorporated nanoparticles. Biocompatible and biodegradable polymers, PLGA and PEG, serve as polymeric micelles for controlled-release of drug. Curcumin as a natural anticancer agent has poor solubility that limits its use in drug therapeutics, while platinum-based Cisplatin exhibits systemic cytotoxicity. These can be overcome via drug delivery in polymeric biocompatible vehicles. The PLGA-PEG-HA conjugate shows the total measurement of 105 bond length with average bond length of 1.274163 Å. The conjugation between PEG and HA occurs at C8-O1 atoms and can be manipulated to improve properties.

A modification in the technique of computing average lengths from the scales of fishes

USGS Publications Warehouse

Van Oosten, John

1953-01-01

In virtually all the studies that employ scales, otollths, or bony structures to obtain the growth history of fishes, it has been the custom to compute lengths for each individual fish and from these data obtain the average growth rates for any particular group. This method involves a considerable amount of mathematical manipulation, time, and effort. Theoretically it should be possible to obtain the same information simply by averaging the scale measurements for each year of life and the length of the fish employed and computing the average lengths from these data. This method would eliminate all calculations for individual fish. Although Van Oosten (1929: 338) pointed out many years ago the validity of this method of computation, his statements apparently have been overlooked by subsequent investigators.

Spatial distribution of the capacity to initiate a secondary embryo in the 32-cell embryo of Xenopus laevis.

PubMed

Kageura, H

1990-12-01

To examine the spatial distribution of dorsal determinants in the early embryos of Xenopus laevis, individual cells from the 32-cell embryo were transplanted into the same tier of the ventral side of a synchronous recipient. Their abilities to initiate a secondary embryo were measured by the incidence of secondary embryos and by the length of the secondary axis relative to the primary embryo. The ability was found to be localized in all cells (A1, B1, C1, and D1) of the dorsal most column and in the vegetal cells (C2 and D2) of the dorsolateral column. Transplanted C1 (subequatorial) cells caused the highest incidence of a secondary embryo and the average relative length of the secondary embryo was also greatest. Effectiveness decreased in the order: D1, B1, D2, C2, and A1. When these results were compared with Dale and Slack's fate map of the 32-cell embryo, it was concluded that the distribution of dorsal determinants is unique and does not coincide with the prospective regions for any tissues, though it is somewhat similar to the prospective region of dorsal endoderm or notochord. From these results it seems that dorsal determinants do not determine a particular tissue in an embryo but rather the "dorsal" region of an embryo.

Stalk-length-dependence of the contractility of Vorticella convallaria

NASA Astrophysics Data System (ADS)

Gul Chung, Eun; Ryu, Sangjin

2017-12-01

Vorticella convallaria is a sessile protozoan of which the spasmoneme contracts on a millisecond timescale. Because this contraction is induced and powered by the binding of calcium ions (Ca2+), the spasmoneme showcases Ca2+-powered cellular motility. Because the isometric tension of V. convallaria increases linearly with its stalk length, it is hypothesized that the contractility of V. convallaria during unhindered contraction depends on the stalk length. In this study, the contractile force and energetics of V. convallaria cells of different stalk lengths were evaluated using a fluid dynamic drag model which accounts for the unsteadiness and finite Reynolds number of the water flow caused by contracting V. convallaria and the wall effect of the no-slip substrate. It was found that the contraction displacement, peak contraction speed, peak contractile force, total mechanical work, and peak power depended on the stalk length. The observed stalk-length-dependencies were simulated using a damped spring model, and the model estimated that the average spring constant of the contracting stalk was 1.34 nN µm-1. These observed length-dependencies of Vorticella’s key contractility parameters reflect the biophysical mechanism of the spasmonemal contraction, and thus they should be considered in developing a theoretical model of the Vorticella spasmoneme.

The influence of incubation time on adenovirus quantitation in A549 cells by most probable number.

PubMed

Cashdollar, Jennifer L; Huff, Emma; Ryu, Hodon; Grimm, Ann C

2016-11-01

Cell culture based assays used to detect waterborne viruses typically call for incubating the sample for at least two weeks in order to ensure that all the culturable virus present is detected. Historically, this estimate was based, at least in part, on the length of time used for detecting poliovirus. In this study, we have examined A549 cells infected with human adenovirus type 2, and have found that a three week incubation of virus infected cells results in a higher number of detected viruses by quantal assay than what is seen after two weeks of incubation, with an average 955% increase in Most Probable Number (MPN) from 2 weeks to 3 weeks. This increase suggests that the extended incubation time is essential for accurately estimating viral titer, particularly for slow-growing viruses, UV treated samples, or samples with low titers of virus. In addition, we found that for some UV-treated samples, there was no detectable MPN at 2 weeks, but after 3 weeks, MPN values were obtained. For UV-treated samples, the average increase in MPN from 2 weeks to 3 weeks was 1401%, while untreated samples averaged a change in MPN of 674%, leading us to believe that the UV-damaged viral DNA may be able to be repaired such that viral replication then occurs. Published by Elsevier B.V.

Variation in leader length of bitterbrush

Treesearch

Richard L. Hubbard; David. Dunaway

1958-01-01

The estimation of herbage production and· utilization in browse plants has been a problem for many years. Most range technicians have simply estimated the average length of twigs or leaders. then expressed use by deer and livestock as a percentage thereof based on the estimated average length left after grazing. Riordan used this method on mountain mahogany (

Cellulosic nanowhiskers. Theory and application of light scattering from polydisperse spheroids in the Rayleigh-Gans-Debye regime.

PubMed

Braun, Birgit; Dorgan, John R; Chandler, John P

2008-04-01

Mathematical treatment of light scattering within the Rayleigh-Gans-Debye limit for spheroids with polydispersity in both length and diameter is developed and experimentally tested using cellulosic nanowhiskers (CNW). Polydispersity indices are obtained by fitting the theoretical formfactor to experimental data. Good agreement is achieved using a polydispersity of 2.3 for the length, independent of the type of acid used. Diameter polydispersities are 2.1 and 3.0 for sulfuric and hydrochloric acids, respectively. These polydispersities allow the determination of average dimensions from the z-average mean-square radius (z) and the weight-average molecular weight (M w) easily obtained from Berry plots. For cotton linter hydrolyzed by hydrochloric acid, the average length and diameter are 244 and 22 nm. This compares to average length and diameter of 272 and 13 nm for sulfuric acid. This study establishes a new light-scattering methodology as a quick and robust tool for size characterization of polydisperse spheroidal nanoparticles.

The GAAS metagenomic tool and its estimations of viral and microbial average genome size in four major biomes.

PubMed

Angly, Florent E; Willner, Dana; Prieto-Davó, Alejandra; Edwards, Robert A; Schmieder, Robert; Vega-Thurber, Rebecca; Antonopoulos, Dionysios A; Barott, Katie; Cottrell, Matthew T; Desnues, Christelle; Dinsdale, Elizabeth A; Furlan, Mike; Haynes, Matthew; Henn, Matthew R; Hu, Yongfei; Kirchman, David L; McDole, Tracey; McPherson, John D; Meyer, Folker; Miller, R Michael; Mundt, Egbert; Naviaux, Robert K; Rodriguez-Mueller, Beltran; Stevens, Rick; Wegley, Linda; Zhang, Lixin; Zhu, Baoli; Rohwer, Forest

2009-12-01

Metagenomic studies characterize both the composition and diversity of uncultured viral and microbial communities. BLAST-based comparisons have typically been used for such analyses; however, sampling biases, high percentages of unknown sequences, and the use of arbitrary thresholds to find significant similarities can decrease the accuracy and validity of estimates. Here, we present Genome relative Abundance and Average Size (GAAS), a complete software package that provides improved estimates of community composition and average genome length for metagenomes in both textual and graphical formats. GAAS implements a novel methodology to control for sampling bias via length normalization, to adjust for multiple BLAST similarities by similarity weighting, and to select significant similarities using relative alignment lengths. In benchmark tests, the GAAS method was robust to both high percentages of unknown sequences and to variations in metagenomic sequence read lengths. Re-analysis of the Sargasso Sea virome using GAAS indicated that standard methodologies for metagenomic analysis may dramatically underestimate the abundance and importance of organisms with small genomes in environmental systems. Using GAAS, we conducted a meta-analysis of microbial and viral average genome lengths in over 150 metagenomes from four biomes to determine whether genome lengths vary consistently between and within biomes, and between microbial and viral communities from the same environment. Significant differences between biomes and within aquatic sub-biomes (oceans, hypersaline systems, freshwater, and microbialites) suggested that average genome length is a fundamental property of environments driven by factors at the sub-biome level. The behavior of paired viral and microbial metagenomes from the same environment indicated that microbial and viral average genome sizes are independent of each other, but indicative of community responses to stressors and environmental conditions.

MagnetoSperm: A microrobot that navigates using weak magnetic fields

NASA Astrophysics Data System (ADS)

Khalil, Islam S. M.; Dijkslag, Herman C.; Abelmann, Leon; Misra, Sarthak

2014-06-01

In this work, a propulsion system similar in motion to a sperm-cell is investigated. This system consists of a structure resembling a sperm-cell with a magnetic head and a flexible tail of 42 μm and 280 μm in length, respectively. The thickness, length, and width of this structure are 5.2 μm, 322 μm, and 42 μm, respectively. The magnetic head includes a 200 nm-thick cobalt-nickel layer. The cobalt-nickel layer provides a dipole moment and allows the flexible structure to align along oscillating weak (less than 5 mT) magnetic field lines, and hence generates a propulsion thrust force that overcomes the drag force. The frequency response of this system shows that the propulsion mechanism allows for swimming at an average speed of 158 ± 32 μm/s at alternating weak magnetic field of 45 Hz. In addition, we experimentally demonstrate controlled steering of the flexible structure towards reference positions.

Laser-zone growth in a Ribbon-To-Ribbon, RTR, process silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Gurtler, R. W.; Baghdadi, A.

1977-01-01

A ribbon-to-ribbon process was used for routine growth of samples for analysis and fabrication into solar cells. One lot of solar cells was completely evaluated: ribbon solar cell efficiencies averaged 9.23% with a highest efficiency of 11.7%. Spherical reflectors have demonstrated significant improvements in laser silicon coupling efficiencies. Material analyses were performed including silicon photovoltage and open circuit photovoltage diffusion length measurements, crystal morphology studies, modulus of rupture measurements, and annealing/gettering studies. An initial economic analysis was performed indicating that ribbon-to-ribbon add-on costs of $.10/watt might be expected in the early 1980's.

Ultrastructural description of Ceratomyxa tenuispora (Myxozoa), a parasite of the marine fish Aphanopus carbo (Trichiuridae), from the Atlantic coast of Madeira Island (Portugal).

PubMed

Casal, Graça; Costa, Graça; Azevedo, Carlos

2007-09-01

The first ultrastructural description of Ceratomyxa tenuispora Kabata, 1960 (Myxozoa, Bivalvulida) from Madeira Island (Portugal), a parasite found in the gall bladder of the commercially important black-scabbard fish, Aphanopus carbo Lowe is presented. This parasite possesses spherical to ellipsoidal disporous trophozoites. Spores have a central crescent-shaped body averaging 11.0 microm in length, 28.5 microm in thickness and 12.1 microm in width. The valves have two long opposite lateral processes (ribbon-like structures or tails), each averaging 173 microm in length. The total thickness of the spore averages 375 microm. The spore has two sub-spherical polar capsules (approximately 5.2 x 4.1 microm), each with a polar filament with 7 to 8 coils. Some ultrastructural aspects of the sporogonic stages are described. The trophozoites develop without contact with epithelial cells. The cytoplasmic membrane has numerous evenly distributed external slender projections about 0.3 to 0.7 microm long. The sporogenesis produces two spores without pansporoblast formation. In the matrix of the capsular primordium, microtubules with an unusual organisation were observed. A binucleate sporoplasm that contains several sporoplasmosomes and dense bodies fills the spore cavity and extends to the tails without penetrating them.

Predicting cell viability within tissue scaffolds under equiaxial strain: multi-scale finite element model of collagen-cardiomyocytes constructs.

PubMed

Elsaadany, Mostafa; Yan, Karen Chang; Yildirim-Ayan, Eda

2017-06-01

Successful tissue engineering and regenerative therapy necessitate having extensive knowledge about mechanical milieu in engineered tissues and the resident cells. In this study, we have merged two powerful analysis tools, namely finite element analysis and stochastic analysis, to understand the mechanical strain within the tissue scaffold and residing cells and to predict the cell viability upon applying mechanical strains. A continuum-based multi-length scale finite element model (FEM) was created to simulate the physiologically relevant equiaxial strain exposure on cell-embedded tissue scaffold and to calculate strain transferred to the tissue scaffold (macro-scale) and residing cells (micro-scale) upon various equiaxial strains. The data from FEM were used to predict cell viability under various equiaxial strain magnitudes using stochastic damage criterion analysis. The model validation was conducted through mechanically straining the cardiomyocyte-encapsulated collagen constructs using a custom-built mechanical loading platform (EQUicycler). FEM quantified the strain gradients over the radial and longitudinal direction of the scaffolds and the cells residing in different areas of interest. With the use of the experimental viability data, stochastic damage criterion, and the average cellular strains obtained from multi-length scale models, cellular viability was predicted and successfully validated. This methodology can provide a great tool to characterize the mechanical stimulation of bioreactors used in tissue engineering applications in providing quantification of mechanical strain and predicting cellular viability variations due to applied mechanical strain.

A new approach to process control using Instability Index

NASA Astrophysics Data System (ADS)

Weintraub, Jeffrey; Warrick, Scott

2016-03-01

The merits of a robust Statistical Process Control (SPC) methodology have long been established. In response to the numerous SPC rule combinations, processes, and the high cost of containment, the Instability Index (ISTAB) is presented as a tool for managing these complexities. ISTAB focuses limited resources on key issues and provides a window into the stability of manufacturing operations. ISTAB takes advantage of the statistical nature of processes by comparing the observed average run length (OARL) to the expected run length (ARL), resulting in a gap value called the ISTAB index. The ISTAB index has three characteristic behaviors that are indicative of defects in an SPC instance. Case 1: The observed average run length is excessively long relative to expectation. ISTAB > 0 is indicating the possibility that the limits are too wide. Case 2: The observed average run length is consistent with expectation. ISTAB near zero is indicating that the process is stable. Case 3: The observed average run length is inordinately short relative to expectation. ISTAB < 0 is indicating that the limits are too tight, the process is unstable or both. The probability distribution of run length is the basis for establishing an ARL. We demonstrate that the geometric distribution is a good approximation to run length across a wide variety of rule sets. Excessively long run lengths are associated with one kind of defect in an SPC instance; inordinately short run lengths are associated with another. A sampling distribution is introduced as a way to quantify excessively long and inordinately short observed run lengths. This paper provides detailed guidance for action limits on these run lengths. ISTAB as a statistical method of review facilitates automated instability detection. This paper proposes a management system based on ISTAB as an enhancement to more traditional SPC approaches.

Design optimization of electric vehicle battery cooling plates for thermal performance

NASA Astrophysics Data System (ADS)

Jarrett, Anthony; Kim, Il Yong

The performance of high-energy battery cells utilized in electric vehicles (EVs) is greatly improved by adequate temperature control. An efficient thermal management system is also desirable to avoid diverting excessive power from the primary vehicle functions. In a battery cell stack, cooling can be provided by including cooling plates: thin metal fabrications which include one or more internal channels through which a coolant is pumped. Heat is conducted from the battery cells into the cooling plate, and transported away by the coolant. The operating characteristics of the cooling plate are determined in part by the geometry of the channel; its route, width, length, etc. In this study, a serpentine-channel cooling plate is modeled parametrically and its characteristics assessed using computational fluid dynamics (CFD). Objective functions of pressure drop, average temperature, and temperature uniformity are defined and numerical optimization is carried out by allowing the channel width and position to vary. The optimization results indicate that a single design can satisfy both pressure and average temperature objectives, but at the expense of temperature uniformity.

Amperometric biosensor based on glassy carbon electrode modified with long-length carbon nanotube and enzyme

NASA Astrophysics Data System (ADS)

Furutaka, Hajime; Nemoto, Kentaro; Inoue, Yuki; Hidaka, Hiroki; Muguruma, Hitoshi; Inoue, Hitoshi; Ohsawa, Tatsuya

2016-05-01

An amperometric biosensor based on a glassy carbon electrode modified with long-length multiwalled carbon nanotubes (MWCNTs) and enzyme nicotinamide-adenine-dinucleotide-dependent glucose dehydrogenase (GDH) is presented. We demonstrate the effect of the MWCNT length on the amperometric response of the enzyme biosensor. The long length of MWCNT is 200 µm (average), whereas the normal length of MWCNT is 1 µm (average). The response of the long MWCNT-GDH electrode is 2 times more sensitive than that of the normal-length MWCNT-GDH electrode in the concentration range from 0.25-35 mM. The result of electrochemical impedance spectroscopy measurements suggest that the long-length MWCNT-GDH electrode formed a better electron transfer network than the normal-length one.

An increase in telomere sister chromatid exchange in murine embryonic stem cells possessing critically shortened telomeres

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

Wang, Yisong; Giannone, Richard J; Wu, Jun

Telomerase deficiency leads to a progressive loss of telomeric DNA that eventually triggers cell apoptosis in human primary cells during prolonged growth in culture. Rare survivors can maintain telomere length through either activation of telomerase or recombination-based telomere lengthening, and thus proliferate indefinitely. We have explored the possibility that telomeres may be maintained through telomere sister chromatid exchange (T-SCE) in murine telomere reverse transcriptase-deficient (mTert -/-) splenocytes and ES cells. Because telomerase deficiency leads to gradual loss of telomeric DNA in mTert -/- splenocytes and ES cells and eventually to chromosomes with telomere signal-free ends (SFEs), we examined these cellmore » types for evidence of sister chromatid exchange at telomeres, and observed an increase in T-SCEs only in a subset of mTert -/- splenocytes or ES cells that possessed multiple SFEs. Furthermore, T-SCEs were more often detected in ES cells than in splenocytes that harbored a similar frequency of SFEs. In mTert heterozygous (mTert +/-) ES cells or splenocytes, which are known to exhibit a decrease in average telomere length but no SFEs, no increase in T-SCE was observed. In addition to T-SCE, other genomic rearrangements (i.e., SCE) were also significantly increased in mTert -/- ES cells possessing critically short telomeres, but not in splenocytes. Our results suggest that animals and cell culture differ in their ability to carry out genomic rearrangements as a means of maintaining telomere integrity when telomeres become critically shortened.« less

Length estimations of presumed upward connecting leaders in lightning flashes to flat water and flat ground

NASA Astrophysics Data System (ADS)

Stolzenburg, Maribeth; Marshall, Thomas C.; Karunarathne, Sumedhe; Orville, Richard E.

2018-10-01

Using video data recorded at 50,000 frames per second for nearby negative lightning flashes, estimates are derived for the length of positive upward connecting leaders (UCLs) that presumably formed prior to new ground attachments. Return strokes were 1.7 to 7.8 km distant, yielding image resolutions of 4.25 to 19.5 m. No UCLs are imaged in these data, indicating those features were too transient or too dim compared to other lightning processes that are imaged at these resolutions. Upper bound lengths for 17 presumed UCLs are determined from the height above flat ground or water of the successful stepped leader tip in the image immediately prior to (within 20 μs before) the return stroke. Better estimates of maximum UCL lengths are determined using the downward stepped leader tip's speed of advance and the estimated return stroke time within its first frame. For 17 strokes, the upper bound length of the possible UCL averages 31.6 m and ranges from 11.3 to 50.3 m. Among the close strokes (those with spatial resolution <8 m per pixel), the five which connected to water (salt water lagoon) have UCL upper bound estimates averaging significantly shorter (24.1 m) than the average for the three close strokes which connected to land (36.9 m). The better estimates of maximum UCL lengths for the eight close strokes average 20.2 m, with slightly shorter average of 18.3 m for the five that connected to water. All the better estimates of UCL maximum lengths are <38 m in this dataset

Capacity of MIMO free space optical communications using multiple partially coherent beams propagation through non-Kolmogorov strong turbulence.

PubMed

Deng, Peng; Kavehrad, Mohsen; Liu, Zhiwen; Zhou, Zhou; Yuan, Xiuhua

2013-07-01

We study the average capacity performance for multiple-input multiple-output (MIMO) free-space optical (FSO) communication systems using multiple partially coherent beams propagating through non-Kolmogorov strong turbulence, assuming equal gain combining diversity configuration and the sum of multiple gamma-gamma random variables for multiple independent partially coherent beams. The closed-form expressions of scintillation and average capacity are derived and then used to analyze the dependence on the number of independent diversity branches, power law α, refractive-index structure parameter, propagation distance and spatial coherence length of source beams. Obtained results show that, the average capacity increases more significantly with the increase in the rank of MIMO channel matrix compared with the diversity order. The effect of the diversity order on the average capacity is independent of the power law, turbulence strength parameter and spatial coherence length, whereas these effects on average capacity are gradually mitigated as the diversity order increases. The average capacity increases and saturates with the decreasing spatial coherence length, at rates depending on the diversity order, power law and turbulence strength. There exist optimal values of the spatial coherence length and diversity configuration for maximizing the average capacity of MIMO FSO links over a variety of atmospheric turbulence conditions.

Peripapillary retinal nerve fiber layer thickness in a population of 6-year-old children: findings by optical coherence tomography.

PubMed

Huynh, Son C; Wang, Xiu Ying; Rochtchina, Elena; Mitchell, Paul

2006-09-01

To study the distribution of retinal nerve fiber layer (RNFL) thickness by ocular and demographic variables in a population-based study of young children. Population-based cross-sectional study. One thousand seven hundred sixty-five of 2238 (78.9%) eligible 6-year-old children participated in the Sydney Childhood Eye Study between 2003 and 2004. Mean age was 6.7 years (50.9% boys). Detailed examination included cycloplegic autorefraction and measurement of axial length. Retinal nerve fiber layer scans using an optical coherence tomographer were performed with a circular scan pattern of 3.4-mm diameter. Multivariate analyses were performed to examine the distribution of RNFL parameters with gender, ethnicity, axial length, and refraction. Peripapillary RNFL thickness and RNFL(estimated integral) (RNFL(EI)), which measures the total cross-sectional area of ganglion cell axons converging onto the optic nerve head. Peripapillary RNFL thickness and RNFL(EI) were normally distributed. The mean+/-standard deviation RNFL average thickness was 103.7+/-11.4 microm and RNFL(EI) was 1.05+/-0.12 mm2. Retinal nerve fiber layer thickness was least for the temporal quadrant (75.7+/-14.7 microm), followed by the nasal (81.7+/-19.6 microm), inferior (127.8+/-20.5 microm), and superior (129.5+/-20.6 microm) quadrants. Multivariate adjusted RNFL average thickness was marginally greater in boys than in girls (104.7 microm vs. 103.2 microm; P = 0.007) and in East Asian than in white children (107.7 microm vs. 102.7 microm; P<0.0001). The RNFL was thinner with greater axial length (P(trend)<0.0001) and less positive spherical equivalent refractions (P(trend) = 0.004). Retinal nerve fiber layer average thickness and RNFL(EI) followed a normal distribution. Retinal nerve fiber layer thickness varied marginally with gender, but differences were more marked between white and East Asian children. Retinal nerve fiber layer thinning was associated with increasing axial length and less positive refractions.

Graded bandgap perovskite solar cells.

PubMed

Ergen, Onur; Gilbert, S Matt; Pham, Thang; Turner, Sally J; Tan, Mark Tian Zhi; Worsley, Marcus A; Zettl, Alex

2017-05-01

Organic-inorganic halide perovskite materials have emerged as attractive alternatives to conventional solar cell building blocks. Their high light absorption coefficients and long diffusion lengths suggest high power conversion efficiencies, and indeed perovskite-based single bandgap and tandem solar cell designs have yielded impressive performances. One approach to further enhance solar spectrum utilization is the graded bandgap, but this has not been previously achieved for perovskites. In this study, we demonstrate graded bandgap perovskite solar cells with steady-state conversion efficiencies averaging 18.4%, with a best of 21.7%, all without reflective coatings. An analysis of the experimental data yields high fill factors of ∼75% and high short-circuit current densities up to 42.1 mA cm -2 . The cells are based on an architecture of two perovskite layers (CH 3 NH 3 SnI 3 and CH 3 NH 3 PbI 3-x Br x ), incorporating GaN, monolayer hexagonal boron nitride, and graphene aerogel.

Growth Patterns Inferred from Anatomical Records 1

PubMed Central

Silk, Wendy Kuhn; Lord, Elizabeth M.; Eckard, Kathleen J.

1989-01-01

Our objective was to test whether accurate growth analyses can be obtained from anatomical records and some mathematical formulas. Roots of Zea mays L. were grown at one of two temperatures (19°C or 29°C) and were prepared with standard techniques for light microscopy. Positions of cell walls were digitized from micrographs. The digitized data were averaged and smoothed and used in formulas to estimate growth trajectories, Z(t), velocities, v(z), and strain rates, r(z), where Z(t) is the location occupied by the cellular particle at time t; and v(z) and r(z) are, respectively, the fields of growth velocity and strain rate. The relationships tested are: for Z(t), t = n * c; v(z) = l(z) * f; and r(z) = f * (∂/∂z (l(z))). In the formulas, n represents the number of cells between the origin and the position Z(t); l(z) is local cell length; the constant c, named the `cellochron,' denotes the time for successive cells to pass a spatial point distal to the meristem; l(z) is local cell length, and f is cell flux. Growth trajectories and velocity fields from the anatomical method are in good agreement with earlier analyses based on marking experiments at the two different temperatures. Growth strain rate fields show an unexpected oscillation which may be due to numerical artifacts or to a real oscillation in cell production rate. Images Figure 2 PMID:16666832

Microglia show altered morphology and reduced arborization in human brain during aging and Alzheimer's disease.

PubMed

Davies, Danielle S; Ma, Jolande; Jegathees, Thuvarahan; Goldsbury, Claire

2017-11-01

Changes in microglia function are involved in Alzheimer's disease (AD) for which ageing is the major risk factor. We evaluated microglial cell process morphologies and their gray matter coverage (arborized area) during ageing and in the presence and absence of AD pathology in autopsied human neocortex. Microglial cell processes were reduced in length, showed less branching and reduced arborized area with aging (case range 52-98 years). This occurred during normal ageing and without microglia dystrophy or changes in cell density. There was a larger reduction in process length and arborized area in AD compared to aged-matched control microglia. In AD cases, on average, 49%-64% of microglia had discontinuous and/or punctate Iba1 labeled processes instead of continuous Iba1 distribution. Up to 16% of aged-matched control microglia displayed discontinuous or punctate features. There was no change in the density of microglial cell bodies in gray matter during ageing or AD. This demonstrates that human microglia show progressive cell process retraction without cell loss during ageing. Additional changes in microglia occur with AD including Iba1 protein puncta and discontinuity. We suggest that reduced microglial arborized area may be an aging-related correlate of AD in humans. These variations in microglial cells during ageing and in AD could reflect changes in neural-glial interactions which are emerging as key to mechanisms involved in ageing and neurodegenerative disease. © 2016 International Society of Neuropathology.

Effects of Age and Heart Failure on Human Cardiac Stem Cell Function

PubMed Central

Cesselli, Daniela; Beltrami, Antonio P.; D'Aurizio, Federica; Marcon, Patrizia; Bergamin, Natascha; Toffoletto, Barbara; Pandolfi, Maura; Puppato, Elisa; Marino, Laura; Signore, Sergio; Livi, Ugolino; Verardo, Roberto; Piazza, Silvano; Marchionni, Luigi; Fiorini, Claudia; Schneider, Claudio; Hosoda, Toru; Rota, Marcello; Kajstura, Jan; Anversa, Piero; Beltrami, Carlo A.; Leri, Annarosa

2011-01-01

Currently, it is unknown whether defects in stem cell growth and differentiation contribute to myocardial aging and chronic heart failure (CHF), and whether a compartment of functional human cardiac stem cells (hCSCs) persists in the decompensated heart. To determine whether aging and CHF are critical determinants of the loss in growth reserve of the heart, the properties of hCSCs were evaluated in 18 control and 23 explanted hearts. Age and CHF showed a progressive decrease in functionally competent hCSCs. Chronological age was a major predictor of five biomarkers of hCSC senescence: telomeric shortening, attenuated telomerase activity, telomere dysfunction-induced foci, and p21Cip1 and p16INK4a expression. CHF had similar consequences for hCSCs, suggesting that defects in the balance between cardiomyocyte mass and the pool of nonsenescent hCSCs may condition the evolution of the decompensated myopathy. A correlation was found previously between telomere length in circulating bone marrow cells and cardiovascular diseases, but that analysis was restricted to average telomere length in a cell population, neglecting the fact that telomere attrition does not occur uniformly in all cells. The present study provides the first demonstration that dysfunctional telomeres in hCSCs are biomarkers of aging and heart failure. The biomarkers of cellular senescence identified here can be used to define the birth date of hCSCs and to sort young cells with potential therapeutic efficacy. PMID:21703415

Solar cells and modules from dentritic web silicon

NASA Technical Reports Server (NTRS)

Campbell, R. B.; Rohatgi, A.; Seman, E. J.; Davis, J. R.; Rai-Choudhury, P.; Gallagher, B. D.

1980-01-01

Some of the noteworthy features of the processes developed in the fabrication of solar cell modules are the handling of long lengths of web, the use of cost effective dip coating of photoresist and antireflection coatings, selective electroplating of the grid pattern and ultrasonic bonding of the cell interconnect. Data on the cells is obtained by means of dark I-V analysis and deep level transient spectroscopy. A histogram of over 100 dentritic web solar cells fabricated in a number of runs using different web crystals shows an average efficiency of over 13%, with some efficiencies running above 15%. Lower cell efficiency is generally associated with low minority carrier time due to recombination centers sometimes present in the bulk silicon. A cost analysis of the process sequence using a 25 MW production line indicates a selling price of $0.75/peak watt in 1986. It is concluded that the efficiency of dentritic web cells approaches that of float zone silicon cells, reduced somewhat by the lower bulk lifetime of the former.

Changes in average length of stay and average charges generated following institution of PSRO review.

PubMed Central

Westphal, M; Frazier, E; Miller, M C

1979-01-01

A five-year review of accounting data at a university hospital shows that immediately following institution of concurrent PSRO admission and length of stay review of Medicare-Medicaid patients, there was a significant decrease in length of stay and a fall in average charges generated per patient against the inflationary trend. Similar changes did not occur for the non-Medicare-Medicaid patients who were not reviewed. The observed changes occurred even though the review procedure rarely resulted in the denial of services to patients, suggesting an indirect effect of review. PMID:393658

Asymptotically optimum multialternative sequential procedures for discernment of processes minimizing average length of observations

NASA Astrophysics Data System (ADS)

Fishman, M. M.

1985-01-01

The problem of multialternative sequential discernment of processes is formulated in terms of conditionally optimum procedures minimizing the average length of observations, without any probabilistic assumptions about any one occurring process, rather than in terms of Bayes procedures minimizing the average risk. The problem is to find the procedure that will transform inequalities into equalities. The problem is formulated for various models of signal observation and data processing: (1) discernment of signals from background interference by a multichannel system; (2) discernment of pulse sequences with unknown time delay; (3) discernment of harmonic signals with unknown frequency. An asymptotically optimum sequential procedure is constructed which compares the statistics of the likelihood ratio with the mean-weighted likelihood ratio and estimates the upper bound for conditional average lengths of observations. This procedure is shown to remain valid as the upper bound for the probability of erroneous partial solutions decreases approaching zero and the number of hypotheses increases approaching infinity. It also remains valid under certain special constraints on the probability such as a threshold. A comparison with a fixed-length procedure reveals that this sequential procedure decreases the length of observations to one quarter, on the average, when the probability of erroneous partial solutions is low.

Short-length and high-density TiO{sub 2} nanorod arrays for the efficient charge separation interface in perovskite solar cells

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

Xiao, Guannan; Shi, Chengwu, E-mail: shicw506@foxmail.com; Zhang, Zhengguo

The TiO{sub 2} nanorod arrays with the length of 70 nm, the diameter of 20 nm, and the areal density of 1000 µm{sup −2} were firstly prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 60 min. Over-500 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layers were successfully obtained by sequential deposition routes using 1.7 M PbI{sub 2}·DMSO complex precursor solution and 0.465 M isopropanol solution of the methylammonium halide mixture with the molar ratio of CH{sub 3}NH{sub 3}I/CH{sub 3}NH{sub 3}Br=85/15. The perovskite solar cellsmore » based on the TiO{sub 2} nanorod array and 560 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer exhibited the best photoelectric conversion efficiency (PCE) of 15.93%, while the corresponding planar perovskite solar cells without the TiO{sub 2} nanorod array and with 530 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer gave the best PCE of 12.82% at the relative humidity of 50–54%. - Graphical abstract: The TiO{sub 2} nanorod arrays with the length of 70 nm, the diameter of 20 nm, and the areal density of 1000 µm{sup −2} were prepared by the hydrothermal method using the aqueous grown solution of 38 mM titanium isopropoxide and 6 M hydrochloric acid at 170 °C for 60 min. The optimal annealing temperature of TiO{sub 2} nanorod arrays was 450 °C. The perovskite solar cells based on the TiO{sub 2} nanorod array and 560 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer exhibited the best photoelectric conversion efficiency (PCE) of 15.93% and the average PCE of 13.41±2.52%, while the corresponding planar perovskite solar cells without the TiO{sub 2} nanorod array and with 530 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer gave the best PCE of 12.82% and the average PCE of 10.54±2.28% at the relative humidity of 50–54%. - Highlights: • Preparation of TiO{sub 2} nanorod array with length of 70 nm and density of 1000 µm{sup −2}. • Influence of annealing temperatures on the -OH content of TiO{sub 2} nanorod arrays. • Preparation of over-500 nm-thickness CH{sub 3}NH{sub 3}PbI{sub 3−x}Br{sub x} absorber layer. • Combination of short-length TiO{sub 2} nanorod array and high-thickness perovskite layer. • The best and average PCE with TiO{sub 2} array of 15.93% and 13.41±2.52% at 50–54% RH.« less

Computational Characterization of Type I collagen-based Extra-cellular Matrix

NASA Astrophysics Data System (ADS)

Liang, Long; Jones, Christopher Allen Rucksack; Lin, Daniel; Jiao, Yang; Sun, Bo

2015-03-01

A model of extracellular matrix (ECM) of collagen fibers has been built, in which cells could communicate with distant partners via fiber-mediated long-range-transmitted stress states. The ECM is modeled as a spring-like fiber network derived from skeletonized confocal microscopy data. Different local and global perturbations have been performed on the network, each followed by an optimized global Monte-Carlo (MC) energy minimization leading to the deformed network in response to the perturbations. In the optimization, a highly efficient local energy update procedure is employed and force-directed MC moves are used, which results in a convergence to the energy minimum state 20 times faster than the commonly used random displacement trial moves in MC. Further analysis and visualization of the distribution and correlation of the resulting force network reveal that local perturbations can give rise to global impacts: the force chains formed with a linear extent much further than the characteristic length scale associated with the perturbation sites and average fiber length. This behavior provides a strong evidence for our hypothesis of fiber-mediated long-range force transmission in ECM networks and the resulting long-range cell-cell mechanical signaling. ASU Seed Grant.

Salmonella O48 Serum Resistance is Connected with the Elongation of the Lipopolysaccharide O-Antigen Containing Sialic Acid

PubMed Central

Pawlak, Aleksandra; Rybka, Jacek; Dudek, Bartłomiej; Krzyżewska, Eva; Rybka, Wojciech; Kędziora, Anna; Klausa, Elżbieta; Bugla-Płoskońska, Gabriela

2017-01-01

Complement is one of the most important parts of the innate immune system. Some bacteria can gain resistance against the bactericidal action of complement by decorating their outer cell surface with lipopolysaccharides (LPSs) containing a very long O-antigen or with specific outer membrane proteins. Additionally, the presence of sialic acid in the LPS molecules can provide a level of protection for bacteria, likening them to human cells, a phenomenon known as molecular mimicry. Salmonella O48, which contains sialic acid in the O-antigen, is the major cause of reptile-associated salmonellosis, a worldwide public health problem. In this study, we tested the effect of prolonged exposure to human serum on strains from Salmonella serogroup O48, specifically on the O-antigen length. After multiple passages in serum, three out of four tested strains became resistant to serum action. The gas-liquid chromatography/tandem mass spectrometry analysis showed that, for most of the strains, the average length of the LPS O-antigen increased. Thus, we have discovered a link between the resistance of bacterial cells to serum and the elongation of the LPS O-antigen. PMID:28934165

Salmonella O48 Serum Resistance is Connected with the Elongation of the Lipopolysaccharide O-Antigen Containing Sialic Acid.

PubMed

Pawlak, Aleksandra; Rybka, Jacek; Dudek, Bartłomiej; Krzyżewska, Eva; Rybka, Wojciech; Kędziora, Anna; Klausa, Elżbieta; Bugla-Płoskońska, Gabriela

2017-09-21

Complement is one of the most important parts of the innate immune system. Some bacteria can gain resistance against the bactericidal action of complement by decorating their outer cell surface with lipopolysaccharides (LPSs) containing a very long O-antigen or with specific outer membrane proteins. Additionally, the presence of sialic acid in the LPS molecules can provide a level of protection for bacteria, likening them to human cells, a phenomenon known as molecular mimicry. Salmonella O48, which contains sialic acid in the O-antigen, is the major cause of reptile-associated salmonellosis, a worldwide public health problem. In this study, we tested the effect of prolonged exposure to human serum on strains from Salmonella serogroup O48, specifically on the O-antigen length. After multiple passages in serum, three out of four tested strains became resistant to serum action. The gas-liquid chromatography/tandem mass spectrometry analysis showed that, for most of the strains, the average length of the LPS O-antigen increased. Thus, we have discovered a link between the resistance of bacterial cells to serum and the elongation of the LPS O-antigen.

Analytical solution for haze values of aluminium-induced texture (AIT) glass superstrates for a-Si:H solar cells.

PubMed

Sahraei, Nasim; Forberich, Karen; Venkataraj, Selvaraj; Aberle, Armin G; Peters, Marius

2014-01-13

Light scattering at randomly textured interfaces is essential to improve the absorption of thin-film silicon solar cells. Aluminium-induced texture (AIT) glass provides suitable scattering for amorphous silicon (a-Si:H) solar cells. The scattering properties of textured surfaces are usually characterised by two properties: the angularly resolved intensity distribution and the haze. However, we find that the commonly used haze equations cannot accurately describe the experimentally observed spectral dependence of the haze of AIT glass. This is particularly the case for surface morphologies with a large rms roughness and small lateral feature sizes. In this paper we present an improved method for haze calculation, based on the power spectral density (PSD) function of the randomly textured surface. To better reproduce the measured haze characteristics, we suggest two improvements: i) inclusion of the average lateral feature size of the textured surface into the haze calculation, and ii) considering the opening angle of the haze measurement. We show that with these two improvements an accurate prediction of the haze of AIT glass is possible. Furthermore, we use the new equation to define optimum morphology parameters for AIT glass to be used for a-Si:H solar cell applications. The autocorrelation length is identified as the critical parameter. For the investigated a-Si:H solar cells, the optimum autocorrelation length is shown to be 320 nm.

Queues with Choice via Delay Differential Equations

NASA Astrophysics Data System (ADS)

Pender, Jamol; Rand, Richard H.; Wesson, Elizabeth

Delay or queue length information has the potential to influence the decision of a customer to join a queue. Thus, it is imperative for managers of queueing systems to understand how the information that they provide will affect the performance of the system. To this end, we construct and analyze two two-dimensional deterministic fluid models that incorporate customer choice behavior based on delayed queue length information. In the first fluid model, customers join each queue according to a Multinomial Logit Model, however, the queue length information the customer receives is delayed by a constant Δ. We show that the delay can cause oscillations or asynchronous behavior in the model based on the value of Δ. In the second model, customers receive information about the queue length through a moving average of the queue length. Although it has been shown empirically that giving patients moving average information causes oscillations and asynchronous behavior to occur in U.S. hospitals, we analytically and mathematically show for the first time that the moving average fluid model can exhibit oscillations and determine their dependence on the moving average window. Thus, our analysis provides new insight on how operators of service systems should report queue length information to customers and how delayed information can produce unwanted system dynamics.

Natural polyploidy in Vanilla planifolia (Orchidaceae).

PubMed

Bory, Séverine; Catrice, Olivier; Brown, Spencer; Leitch, Ilia J; Gigant, Rodolphe; Chiroleu, Frédéric; Grisoni, Michel; Duval, Marie-France; Besse, Pascale

2008-10-01

Vanilla planifolia accessions cultivated in Reunion Island display important phenotypic variation, but little genetic diversity is demonstrated by AFLP and SSR markers. This study, based on analyses of flow cytometry data, Feulgen microdensitometry data, chromosome counts, and stomatal length measurements, was performed to determine whether polyploidy could be responsible for some of the intraspecific phenotypic variation observed. Vanilla planifolia exhibited an important variation in somatic chromosome number in root cells, as well as endoreplication as revealed by flow cytometry. Nevertheless, the 2C-values of the 50 accessions studied segregated into three distinct groups averaging 5.03 pg (for most accessions), 7.67 pg (for the 'Stérile' phenotypes), and 10.00 pg (for the 'Grosse Vanille' phenotypes). For the three groups, chromosome numbers varied from 16 to 32, 16 to 38, and 22 to 54 chromosomes per cell, respectively. The stomatal length showed a significant variation from 37.75 microm to 48.25 microm. Given that 2C-values, mean chromosome numbers, and stomatal lengths were positively correlated and that 'Stérile' and 'Grosse Vanille' accessions were indistinguishable from 'Classique' accessions using molecular markers, the occurrence of recent autotriploid and autotetraploid types in Reunion Island is supported. This is the first report showing evidence of a recent autopolyploidy in V. planifolia contributing to the phenotypic variation observed in this species.

The Stochastic Dynamics of Filopodial Growth

NASA Astrophysics Data System (ADS)

Papoian, Garegin A.; Lan, Yueheng; Zhuravlev, Pavel

2008-03-01

A filopodium is a cytoplasmic projection, exquisitely built and regulated, which extends from the leading edge of the migrating cell, exploring the cell's neighborhood. Commonly, filopodia grow and retract after their initiation, exhibiting rich dynamical behaviors. We model the growth of a filopodium based on a stochastic description which incorporates mechanical, physical and biochemical components. Our model provides a full stochastic treatment of the actin monomer diffusion and polymerization of each individual actin filament under stress of the fluctuating membrane. We have investigated the length distribution of individual filaments in a growing filopodium and studied how it depends on various physical parameters. The distribution of filament lengths turned out to be narrow, which we explained by the negative feedback created by the membrane load and monomeric G-actin gradient. We also discovered that filopodial growth is strongly diminished upon increasing retrograde flow, suggesting that regulating the retrograde flow rate would be a highly efficient way to control filopodial extension dynamics. The filopodial length increases as the membrane fluctuations decrease, which we attributed to the unequal loading of the mem- brane force among individual filaments, which, in turn, results in larger average polymerization rates. We also observed significant diffusional noise of G-actin monomers, which leads to smaller G-actin flux along the filopodial tube compared with the prediction using the diffusion equation.

The Impact of Averaging Window Length on the “Desaturation” Indexes Obtained Via Overnight Pulse Oximetry at High Altitude

PubMed Central

Cross, Troy J.; Keller-Ross, Manda; Issa, Amine; Wentz, Robert; Taylor, Bryan; Johnson, Bruce

2015-01-01

Study Objectives: To determine the impact of averaging window-length on the “desaturation” indexes (DIs) obtained via overnight pulse oximetry (SpO2) at high altitude. Design: Overnight SpO2 data were collected during a 10-day sojourn at high altitude. SpO2 was obtained using a commercial wrist-worn finger oximeter whose firmware was modified to store unaveraged beat-to-beat data. Simple moving averages of window lengths spanning 2 to 20 cardiac beats were retrospectively applied to beat-to-beat SpO2 datasets. After SpO2 artifacts were removed, the following DIs were then calculated for each of the averaged datasets: oxygen desaturation index (ODI); total sleep time with SpO2 < 80% (TST < 80), and the lowest SpO2 observed during sleep (SpO2 low). Setting: South Base Camp, Mt. Everest (5,364 m elevation). Participants: Five healthy, adult males (35 ± 5 y; 180 ± 1 cm; 85 ± 4 kg). Interventions: N/A. Measurements and Results: 49 datasets were obtained from the 5 participants, totalling 239 hours of data. For all window lengths ≥ 2 beats, ODI and TST < 80 were lower, and SpO2 low was higher than those values obtained from the beat-to-beat SpO2 time series data (P < 0.05). Conclusions: Our findings indicate that increasing oximeter averaging window length progressively underestimates the frequency and magnitude of sleep disordered breathing events at high altitude, as indirectly assessed via the desaturation indexes. Citation: Cross TJ, Keller-Ross M, Issa A, Wentz R, Taylor B, Johnson B. The impact of averaging window length on the “desaturation” indexes obtained via overnight pulse oximetry at high altitude. SLEEP 2015;38(8):1331–1334. PMID:25581919

Principles determining the structure of high-pressure forms of metals: The structures of cesium(IV) and cesium(V)

PubMed Central

Pauling, Linus

1989-01-01

Consideration of the relation between bond length and bond number and the average atomic volume for different ways of packing atoms leads to the conclusion that the average ligancy of atoms in a metal should increase when a phase change occurs on increasing the pressure. Minimum volume for each value of the ligancy results from triangular coordination polyhedra (with triangular faces), such as the icosahedron and the Friauf polyhedron. Electron transfer may permit atoms of an element to assume different ligancies. Application of these principles to Cs(IV) and Cs(V), which were previously assigned structures with ligancy 8 and 6, respectively, has led to the assignment to Cs(IV) of a primitive cubic unit cell with a = 16.11 Å and with about 122 atoms in the cube and to Cs(V) of a primitive cubic unit cell resembling that of Mg32(Al,Zn)49, with a = 16.97 Å and with 162 atoms in the cube. PMID:16578839

Non-invasive method to detect the changes of glucose concentration in whole blood using photometric technique.

PubMed

Rajan, Shiny Amala Priya; Towe, Bruce C

2014-01-01

A non-invasive method is developed to monitor rapid changes in blood glucose levels in diabetic patients. The system depends on an optical cell built with a LED that emits light of wavelength 535nm, which is a peak absorbance of hemoglobin. As the glucose concentration in blood decreases, its osmolarity also decreases and the Red Blood Cells (RBCs) swell and decrease the path length absorption coefficient. Decreasing absorption coefficient increases the transmission of light through the whole blood. The system was tested with a constructed optical cell that held whole blood in a capillary tube. As expected the light transmitted to the photodiode increases with decreasing glucose concentration. The average response time of the system was between 30-40 seconds.

Effects of donor cells' sex on nuclear transfer efficiency and telomere lengths of cloned goats.

PubMed

Liu, H-J; Peng, H; Hu, C-C; Li, X-Y; Zhang, J-L; Zheng, Z; Zhang, W-C

2016-10-01

The aim of this study was to investigate the effects of donor cells' sex on nuclear transfer efficiency and telomere length of cloned goats from adult skin fibroblast cells. The telomere length of somatic cell cloned goats and their offspring was determined by measuring their mean terminal restriction fragment (TRF) length. The result showed that (i) reconstructed embryos with fibroblast cells from males Boer goats obtained significantly higher kids rate and rate of live kids than those of female embryos and (ii) the telomere lengths of four female cloned goats were shorter compared to their donor cells, but five male cloned goats had the same telomere length with their donor cells, mainly due to great variation existed among them. The offspring from female cloned goats had the same telomere length with their age-matched counterparts. In conclusion, the donor cells' sex had significant effects on nuclear transfer efficiency and telomere lengths of cloned goats. © 2016 Blackwell Verlag GmbH.

Aging of mesenchymal stem cell in vitro

PubMed Central

Bonab, Mandana Mohyeddin; Alimoghaddam, Kamran; Talebian, Fatemeh; Ghaffari, Syed Hamid; Ghavamzadeh, Ardeshir; Nikbin, Behrouz

2006-01-01

Background A hot new topic in medical treatment is the use of mesenchymal stem cells (MSC) in therapy. The low frequency of this subpopulation of stem cells in bone marrow (BM) necessitates their in vitro expansion prior to clinical use. We evaluated the effect of long term culture on the senescence of these cells. Results The mean long term culture was 118 days and the mean passage number was 9. The average number of PD decreased from 7.7 to 1.2 in the 10th passage. The mean telomere length decreased from 9.19 Kbp to 8.7 kbp in the 9th passage. Differentiation potential dropped from the 6th passage on. The culture's morphological abnormalities were typical of the Hayflick model of cellular aging. Conclusion We believe that MSC enter senescence almost undetectably from the moment of in vitro culturing. Simultaneously these cells are losing their stem cell characteristics. Therefore, it is much better to consider them for cell and gene therapy early on. PMID:16529651

Influence of Stress and Antibiotic Resistance on Cell-Length Distribution in Mycobacterium tuberculosis Clinical Isolates

PubMed Central

Vijay, Srinivasan; Vinh, Dao N.; Hai, Hoang T.; Ha, Vu T. N.; Dung, Vu T. M.; Dinh, Tran D.; Nhung, Hoang N.; Tram, Trinh T. B.; Aldridge, Bree B.; Hanh, Nguyen T.; Thu, Do D. A.; Phu, Nguyen H.; Thwaites, Guy E.; Thuong, Nguyen T. T.

2017-01-01

Mycobacterial cellular variations in growth and division increase heterogeneity in cell length, possibly contributing to cell-to-cell variation in host and antibiotic stress tolerance. This may be one of the factors influencing Mycobacterium tuberculosis persistence to antibiotics. Tuberculosis (TB) is a major public health problem in developing countries, antibiotic persistence, and emergence of antibiotic resistance further complicates this problem. We wanted to investigate the factors influencing cell-length distribution in clinical M. tuberculosis strains. In parallel we examined M. tuberculosis cell-length distribution in a large set of clinical strains (n = 158) from ex vivo sputum samples, in vitro macrophage models, and in vitro cultures. Our aim was to understand the influence of clinically relevant factors such as host stresses, M. tuberculosis lineages, antibiotic resistance, antibiotic concentrations, and disease severity on the cell size distribution in clinical M. tuberculosis strains. Increased cell size and cell-to-cell variation in cell length were associated with bacteria in sputum and infected macrophages rather than liquid culture. Multidrug-resistant (MDR) strains displayed increased cell length heterogeneity compared to sensitive strains in infected macrophages and also during growth under rifampicin (RIF) treatment. Importantly, increased cell length was also associated with pulmonary TB disease severity. Supporting these findings, individual host stresses, such as oxidative stress and iron deficiency, increased cell-length heterogeneity of M. tuberculosis strains. In addition we also observed synergism between host stress and RIF treatment in increasing cell length in MDR-TB strains. This study has identified some clinical factors contributing to cell-length heterogeneity in clinical M. tuberculosis strains. The role of these cellular adaptations to host and antibiotic tolerance needs further investigation. PMID:29209302

Copper Oxide Nanoparticles Impact Several Toxicological Endpoints and Cause Neurodegeneration in Caenorhabditis elegans

PubMed Central

Zanon, Tyler; Kappell, Anthony D.; Petrella, Lisa N.; Andersen, Erik C.; Hristova, Krassimira R.

2016-01-01

Engineered nanoparticles are becoming increasingly incorporated into technology and consumer products. In 2014, over 300 tons of copper oxide nanoparticles were manufactured in the United States. The increased production of nanoparticles raises concerns regarding the potential introduction into the environment or human exposure. Copper oxide nanoparticles commonly release copper ions into solutions, which contribute to their toxicity. We quantified the inhibitory effects of both copper oxide nanoparticles and copper sulfate on C. elegans toxicological endpoints to elucidate their biological effects. Several toxicological endpoints were analyzed in C. elegans, including nematode reproduction, feeding behavior, and average body length. We examined three wild C. elegans isolates together with the Bristol N2 laboratory strain to explore the influence of different genotypic backgrounds on the physiological response to copper challenge. All strains exhibited greater sensitivity to copper oxide nanoparticles compared to copper sulfate, as indicated by reduction of average body length and feeding behavior. Reproduction was significantly reduced only at the highest copper dose, though still more pronounced with copper oxide nanoparticles compared to copper sulfate treatment. Furthermore, we investigated the effects of copper oxide nanoparticles and copper sulfate on neurons, cells with known vulnerability to heavy metal toxicity. Degeneration of dopaminergic neurons was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, mutants in the divalent-metal transporters, smf-1 or smf-2, showed increased tolerance to copper exposure, implicating both transporters in copper-induced neurodegeneration. These results highlight the complex nature of CuO nanoparticle toxicity, in which a nanoparticle-specific effect was observed in some traits (average body length, feeding behavior) and a copper ion specific effect was observed for other traits (neurodegeneration, response to stress). PMID:27911941

A multidimensional generalization of Heilbronn's theorem on the average length of a finite continued fraction

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

Illarionov, A A

2014-03-31

Heilbronn's theorem on the average length of a finite continued fraction is generalized to the multidimensional case in terms of relative minima of the lattices which were introduced by Voronoy and Minkowski. Bibliography: 21 titles.

Faraday waves in a Hele-Shaw cell

NASA Astrophysics Data System (ADS)

Li, Jing; Li, Xiaochen; Chen, Kaijie; Xie, Bin; Liao, Shijun

2018-04-01

We investigate Faraday waves in a Hele-Shaw cell via experimental, numerical, and theoretical studies. Inspired by the Kelvin-Helmholtz-Darcy theory, we develop the gap-averaged Navier-Stokes equations and end up with the stable standing waves with half frequency of the external forced vibration. To overcome the dependency of a numerical model on the experimental parameter of wave length, we take two-phase flow into consideration and a novel dispersion relation is derived. The numerical results compare well with our experimental data, which effectively validates our proposed mathematical model. Therefore, this model can produce robust solutions of Faraday wave patterns and resolve related physical phenomena, which demonstrates the practical importance of the present study.

Simulation study of entropy production in the one-dimensional Vlasov system

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

Dai, Zongliang, E-mail: liangliang1223@gmail.com; Wang, Shaojie

2016-07-15

The coarse-grain averaged distribution function of the one-dimensional Vlasov system is obtained by numerical simulation. The entropy productions in cases of the random field, the linear Landau damping, and the bump-on-tail instability are computed with the coarse-grain averaged distribution function. The computed entropy production is converged with increasing length of coarse-grain average. When the distribution function differs slightly from a Maxwellian distribution, the converged value agrees with the result computed by using the definition of thermodynamic entropy. The length of the coarse-grain average to compute the coarse-grain averaged distribution function is discussed.

Microtubules and epithem-cell morphogenesis in hydathodes of Pilea cadierei.

PubMed

Galatis, B

1988-12-01

When cell divisions have ceased, the epithem of the hydathodes of Pilea cadierei Gagnep. et Guill. consists of small polyhedral cells exhibiting a meristematic appearance, and completely lacks intercellular spaces. The cortical microtubules in epithem cells exhibit a unique organization: they are not scattered along the whole wall surface but form groups lying at some distance from each other. In sections, from two to eight groups of microtubules can be observed, each lining a wall region averaging between 0.5 and 1.5 μm in length. These groups represent sections of microtubule bundles girdling a major part or the whole of the cell periphery. They are connected to one another by anastomoses, forming a microtubular reticulum. The assembly of microtubule bundles is followed by the appearance of distinct local thickenings in the adjacent wall areas. The cellulose microfibrils in the thickenings are deposited in parallel to the underlying microtubules. Gradually, the vacuolating epithem cells undergo swelling, except for the areas bounded by the wall thickenings. Since the latter, and actually their constituent bundles of cellulose microfibrils, cannot extend in length the differential cell growth results in schizogenous formation of intercellular spaces between contiguous cell walls at their thickened regions. The spaces then broaden and merge to become an extensive intercellular space system. As a result of the above processes, the epithem cells become constricted and finally deeply lobed. The observations show that (i) the cortical microtubules are intimately involved in the morphogenesis of the epithem cells and (ii) the initiation and development of the epithem intercellular spaces is a phenomenon directly related to cell morphogenesis and therefore to the cortical microtubule cytoskeleton. The sites of initiation of these spaces are highly predictable.

In vitro neurotoxic hazard characterization of different tricresyl phosphate (TCP) isomers and mixtures.

PubMed

Duarte, Daniel J; Rutten, Joost M M; van den Berg, Martin; Westerink, Remco H S

2017-03-01

Exposure to tricresyl phosphates (TCPs), via for example contaminated cabin air, has been associated with health effects including the so-called aerotoxic syndrome. While TCP neurotoxicity is mainly attributed to ortho-isomers like tri-ortho-cresyl phosphate (ToCP), recent exposure and risk assessments indicate that ToCP levels in cabin air are very low. However, the neurotoxic potential of non-ortho TCP isomers and TCP mixtures is largely unknown. We therefore measured effects of exposure (up to 48h) to different TCP isomers, mixtures and the metabolite of ToCP (CBDP: cresyl saligenin phosphate) on cell viability and mitochondrial activity, spontaneous neuronal electrical activity, and neurite outgrowth in primary rat cortical neurons. The results demonstrate that exposure to TCPs (24-48h, up to 10μM) increases mitochondrial activity, without affecting cell viability. Effects of acute TCP exposure (30min) on neuronal electrical activity are limited. However, electrical activity is markedly decreased for the majority of TCPs (10μM) following 48h exposure. Additional preliminary data indicate that exposure to TCPs (48h, 10μM) did not affect the number of neurites per cell or average neurite length, except for TmCP and the analytical TCP mixture (Sigma) that induced a reduction of average neurite length. The combined neurotoxicity data demonstrate that the different TCPs, including ToCP, are roughly equipotent and a clear structure-activity relation is not apparent for the studied endpoints. The no-observed-effect-concentrations (1μM) are well above current exposure levels indicating limited neurotoxic health risk, although exposures may have been higher in the past. Moreover, prolonged and/or repeated exposure to TCPs may exacerbate the observed neurotoxic effects, which argues for additional research. Copyright © 2016 Elsevier B.V. All rights reserved.

Unit and internal chain profiles of maca amylopectin.

PubMed

Zhang, Ling; Li, Guantian; Yao, Weirong; Zhu, Fan

2018-03-01

Unit chain length distributions of amylopectin and its φ, β-limit dextrins, which reflect amylopectin internal structure from three maca starches, were determined by high-performance anion-exchange chromatography with pulsed amperometric detection after debranching, and the samples were compared with maize starch. The amylopectins exhibited average chain lengths ranging from 16.72 to 17.16, with ranges of total internal chain length, external chain length, and internal chain length of the maca amylopectins at 12.49 to 13.68, 11.24 to 11.89, and 4.27 to 4.48. The average chain length, external chain length, internal chain length, and total internal chain length were comparable in three maca amylopectins. Amylopectins of the three maca genotypes studied here presented no significant differences in their unit chain length profiles, but did show significant differences in their internal chain profiles. Additional genetic variations between different maca genotypes need to be studied to provide unit- and internal chain profiles of maca amylopectin. Copyright © 2017. Published by Elsevier Ltd.

Three-disk microswimmer in a supported fluid membrane

NASA Astrophysics Data System (ADS)

Ota, Yui; Hosaka, Yuto; Yasuda, Kento; Komura, Shigeyuki

2018-05-01

A model of three-disk micromachine swimming in a quasi-two-dimensional supported membrane is proposed. We calculate the average swimming velocity as a function of the disk size and the arm length. Due to the presence of the hydrodynamic screening length in the quasi-two-dimensional fluid, the geometric factor appearing in the average velocity exhibits three different asymptotic behaviors depending on the microswimmer size and the hydrodynamic screening length. This is in sharp contrast with a microswimmer in a three-dimensional bulk fluid that shows only a single scaling behavior. We also find that the maximum velocity is obtained when the disks are equal-sized, whereas it is minimized when the average arm lengths are identical. The intrinsic drag of the disks on the substrate does not alter the scaling behaviors of the geometric factor.

Silicon solar cell process development, fabrication, and analysis

NASA Technical Reports Server (NTRS)

Yoo, H. I.; Iles, P. A.; Leung, D. C.

1981-01-01

Work has progressed in fabrication and characterization of solar cells from ubiquitous crystallization process (UCP) wafers and LASS ribbons. Gettering tests applied to UCP wafers made little change on their performance compared with corresponding baseline data. Advanced processes such as shallow junction (SJ), back surface field (BSF), and multilayer antireflection (MLAR) were also applied. While BSF by Al paste had shunting problems, cells with SJ and BSF by evaporated Al, and MLAR did achieve 14.1% AMI on UCP silicon. The study of LASS material was very preliminary. Only a few cells with SJ, BSR, (no BSF) and MLAR were completed due to mechanical yield problems after lapping the material. Average efficiency was 10.7% AMI with 13.4% AMI for CZ controls. Relatively high minority carrier diffusion lengths were obtained. The lower than expected Jsc could be partially explained by low active area due to irregular sizes.

Intelligence and Complexity of the Averaged Evoked Potential: An Attentional Theory.

ERIC Educational Resources Information Center

Bates, Tim; And Others

1995-01-01

A study measuring average evoked potentials in 21 college students finds that intelligence test scores correlate significantly with the difference between string length in attended and nonattended conditions, a finding that suggests that previous inconsistencies in reporting string length-intelligence correlations may have resulted from confound…

Self-Organization of Embryonic Genetic Oscillators into Spatiotemporal Wave Patterns

PubMed Central

Tsiairis, Charisios D.; Aulehla, Alexander

2016-01-01

Summary In vertebrate embryos, somites, the precursor of vertebrae, form from the presomitic mesoderm (PSM), which is composed of cells displaying signaling oscillations. Cellular oscillatory activity leads to periodic wave patterns in the PSM. Here, we address the origin of such complex wave patterns. We employed an in vitro randomization and real-time imaging strategy to probe for the ability of cells to generate order from disorder. We found that, after randomization, PSM cells self-organized into several miniature emergent PSM structures (ePSM). Our results show an ordered macroscopic spatial arrangement of ePSM with evidence of an intrinsic length scale. Furthermore, cells actively synchronize oscillations in a Notch-signaling-dependent manner, re-establishing wave-like patterns of gene activity. We demonstrate that PSM cells self-organize by tuning oscillation dynamics in response to surrounding cells, leading to collective synchronization with an average frequency. These findings reveal emergent properties within an ensemble of coupled genetic oscillators. PMID:26871631

Process Research On Polycrystalline Silicon Material (PROPSM). [flat plate solar array project

NASA Technical Reports Server (NTRS)

Culik, J. S.

1983-01-01

The performance-limiting mechanisms in large-grain (greater than 1 to 2 mm in diameter) polycrystalline silicon solar cells were investigated by fabricating a matrix of 4 sq cm solar cells of various thickness from 10 cm x 10 cm polycrystalline silicon wafers of several bulk resistivities. Analysis of the illuminated I-V characteristics of these cells suggests that bulk recombination is the dominant factor limiting the short-circuit current. The average open-circuit voltage of the polycrystalline solar cells is 30 to 70 mV lower than that of co-processed single-crystal cells; the fill-factor is comparable. Both open-circuit voltage and fill-factor of the polycrystalline cells have substantial scatter that is not related to either thickness or resistivity. This implies that these characteristics are sensitive to an additional mechanism that is probably spatial in nature. A damage-gettering heat-treatment improved the minority-carrier diffusion length in low lifetime polycrystalline silicon, however, extended high temperature heat-treatment degraded the lifetime.

Transfected connexin45 alters gap junction permeability in cells expressing endogenous connexin43

PubMed Central

1995-01-01

Many cells express multiple connexins, the gap junction proteins that interconnect the cytosol of adjacent cells. Connexin43 (Cx43) channels allow intercellular transfer of Lucifer Yellow (LY, MW = 443 D), while connexin45 (Cx45) channels do not. We transfected full-length or truncated chicken Cx45 into a rat osteosarcoma cell line ROS-17/2.8, which expresses endogenous Cx43. Both forms of Cx45 were expressed at high levels and colocalized with Cx43 at plasma membrane junctions. Cells transfected with full-length Cx45 (ROS/Cx45) and cells transfected with Cx45 missing the 37 carboxyl-terminal amino acids (ROS/Cx45tr) showed 30-60% of the gap junctional conductance exhibited by ROS cells. Intercellular transfer of three negatively charged fluorescent reporter molecules was examined. In ROS cells, microinjected LY was transferred to an average of 11.2 cells/injected cell, while dye transfer between ROS/Cx45 cells was reduced to 3.9 transfer between ROS/Cx45 cells was reduced to 3.9 cells. In contrast, ROS/Cx45tr cells transferred LY to > 20 cells. Transfer of calcein (MW = 623 D) was also reduced by approximately 50% in ROS/Cx45 cells, but passage of hydroxycoumarin carboxylic acid (HCCA; MW = 206 D) was only reduced by 35% as compared to ROS cells. Thus, introduction of Cx45 altered intercellular coupling between cells expressing Cx43, most likely the result of direct interaction between Cx43 and Cx45. Transfection of Cx45tr and Cx45 had different effects in ROS cells, consistent with a role of the carboxyl-terminal domain of Cx45 in determining gap junction permeability or interactions between connexins. These data suggest that coexpression of multiple connexins may enable cells to achieve forms of intercellular communication that cannot be attained by expression of a single connexin. PMID:7642714

[Neuron differential attachment purification and its influence factor].

PubMed

Li, Jun; Feng, Daxiong; Huang, Yize; Ye, Fei

2010-02-01

Neuron purification is essential to procedure of various nerve cell experimental research, however, at present there is few reports on the effect of various factors on neural axons during purification. To find out a simple method of neuron purification, and to investigate the influence factors of corresponding purification culture in dorsal root ganglion (DRG) tissue culture on beta3-tubulin positive axon. The DRGs were obtained from the 3 days neonatal SD rat microscopically and were made into cell suspension. Then, the amount of attached DRG neurons and nonneuronal cells in poly-D-lysine (PDL) group, PDL/Laminin (PDL/LN) group and collagen-I (Col I) group was observed from 10 to 100 minutes. Then, the extension and arborization of beta3-tubulin positive axons were observed after 72 hours completely randomised DRG tissue culture for the research of the influences among culture substrates (PDL, PDL/LN, and Col I), FBS (0, 5%, and 10%), 5 fluorouracil (5-Fu, 0, 20, and 40 micromol/L), and cytarabine (Ara-C, 0, 10, and 20 micromol/L). Adherent cells were observed instantly after inoculation by inverted phase contrast microscope and inverted fluorescence microscope; after cell suspension was removed, adherent growth of DRGn cells and non-DRGn cells were still seen. In PDL group, the amount of NSE negative cells was significantly higher than that of NSE positive cells at 10 and 30 minutes (P < 0.05); the amount of NSE positive cells was significantly higher than that of NSE negative cells at 80, 90 and 100 minutes (P < 0.05). In PDL/LN group, there was no significant difference (P > 0.05) in the amount of NSE negative cells and NSE positive cells at 10, 20, 30, 40, and 50 minutes; the amount of NSE positive cells was significantly higher (P < 0.05) than that of NSE negative cells at 60, 70, 80, 90, 100 minutes. In Col I group, the amount of NSE negative cells was higher than that of NSE positive cells at 10-40 minutes, but showing no significant difference (P > 0.05); the amount of NSE positive cells was significantly higher (P < 0.05) than that of NSE negative cells at 70-100 minutes. At 72 hours after DRG tissue culture, the best result of beta3-tubulin positive axon extension and arborization was obtained when the substrate level was PDL/LN, and the average length of PDL/LN level was significantly larger than that of other two substrates (P < 0.05). The highest number of beta3-tubulin positive axon distal end was obtained at 5% concentration level of FBS (P < 0.05), but showing no significant differences in beta3-tubulin positive axon length among three levels (P > 0.05). Both the most of beta3-tubulin positive axon distal ends and the longest beta3-tubulin positive axon average length were obtained at 0 micromol/L concentration level of 5-Fu, showing significant differences between 0 micromol/L level and 20, 40 micromol/L levels (P < 0.05). A similar result of 33-tubulin positive axon distal end was got at the 0 micromol/L level and 10 micromol/L level of Ara-C, which was significantly higher than that of 20 micromol/L level (P < 0.05). A purified DRG neuron suspension for neuron culture could be obtained via PDL differential attachment for 30 minutes. When DRG neuron culture, neuron special medium, PDL/LN substrate and 10 micromol/L Ara-C are recommended in beta3-tubulin positive axon research.

Poly(acrylic acid)-regulated Synthesis of Rod-Like Calcium Carbonate Nanoparticles for Inducing the Osteogenic Differentiation of MC3T3-E1 Cells.

PubMed

Yang, Wei; Yao, Chenxue; Cui, Zhengyang; Luo, Dandan; Lee, In-Seop; Yao, Juming; Chen, Cen; Kong, Xiangdong

2016-05-06

Calcium carbonate, especially with nanostructure, has been considered as a good candidate material for bone regeneration due to its excellent biodegradability and osteoconductivity. In this study, rod-like calcium carbonate nanoparticles (Rod-CC NPs) with desired water dispersibility were achieved with the regulation of poly (acrylic acid). Characterization results revealed that the Rod-CC NPs had an average length of 240 nm, a width of 90 nm with an average aspect ratio of 2.60 and a negative ζ-potential of -22.25 ± 0.35 mV. The degradation study illustrated the nanoparticles degraded 23% at pH 7.4 and 45% at pH 5.6 in phosphate-buffered saline (PBS) solution within three months. When cultured with MC3T3-E1 cells, the Rod-CC NPs exhibited a positive effect on the proliferation of osteoblast cells. Alkaline phosphatase (ALP) activity assays together with the osteocalcin (OCN) and bone sialoprotein (BSP) expression observations demonstrated the nanoparticles could induce the differentiation of MC3T3-E1 cells. Our study developed well-dispersed rod-like calcium carbonate nanoparticles which have great potential to be used in bone regeneration.

Poly(acrylic acid)-regulated Synthesis of Rod-Like Calcium Carbonate Nanoparticles for Inducing the Osteogenic Differentiation of MC3T3-E1 Cells

PubMed Central

Yang, Wei; Yao, Chenxue; Cui, Zhengyang; Luo, Dandan; Lee, In-Seop; Yao, Juming; Chen, Cen; Kong, Xiangdong

2016-01-01

Calcium carbonate, especially with nanostructure, has been considered as a good candidate material for bone regeneration due to its excellent biodegradability and osteoconductivity. In this study, rod-like calcium carbonate nanoparticles (Rod-CC NPs) with desired water dispersibility were achieved with the regulation of poly (acrylic acid). Characterization results revealed that the Rod-CC NPs had an average length of 240 nm, a width of 90 nm with an average aspect ratio of 2.60 and a negative ζ-potential of −22.25 ± 0.35 mV. The degradation study illustrated the nanoparticles degraded 23% at pH 7.4 and 45% at pH 5.6 in phosphate-buffered saline (PBS) solution within three months. When cultured with MC3T3-E1 cells, the Rod-CC NPs exhibited a positive effect on the proliferation of osteoblast cells. Alkaline phosphatase (ALP) activity assays together with the osteocalcin (OCN) and bone sialoprotein (BSP) expression observations demonstrated the nanoparticles could induce the differentiation of MC3T3-E1 cells. Our study developed well-dispersed rod-like calcium carbonate nanoparticles which have great potential to be used in bone regeneration. PMID:27164090

Formic acid production using a microbial electrolysis desalination and chemical-production cell.

PubMed

Lu, Yaobin; Luo, Haiping; Yang, Kunpeng; Liu, Guangli; Zhang, Renduo; Li, Xiao; Ye, Bo

2017-11-01

The aim of this study was to investigate the feasibility and optimization of formic acid production in the microbial electrolysis desalination and chemical-production cell (MEDCC). The maximum current density in the MEDCC with 72cm of the anode fiber length (72-MEDCC) reached 24.0±2.0A/m 2 , which was much higher than previously reported. The maximum average formic acid production rate in the 72-MEDCC was 5.28 times higher than that in the MEDCC with 24cm of the anode fiber length (37.00±1.15vs. 7.00±0.25mg/h). High performance in the 72-MEDCC was attributed to small membrane spacing (1mm), high flow rate (1500μL/min) on the membrane surface and high anode biomass. The minimum electricity consumption of 0.34±0.04kWh/kg in the 72-MEDCC was only 3.1-18.8% of those in the EDBMs. The MEDCC should be a promising technology for the formic acid production. Copyright © 2017 Elsevier Ltd. All rights reserved.

Human TSCM cell dynamics in vivo are compatible with long-lived immunological memory and stemness.

PubMed

Del Amo, Pedro Costa; Beneytez, Julio Lahoz; Boelen, Lies; Ahmed, Raya; Miners, Kelly L; Zhang, Yan; Roger, Laureline; Jones, Rhiannon E; Marraco, Silvia A Fuertes; Speiser, Daniel E; Baird, Duncan M; Price, David A; Ladell, Kristin; Macallan, Derek; Asquith, Becca

2018-06-22

Adaptive immunity relies on the generation and maintenance of memory T cells to provide protection against repeated antigen exposure. It has been hypothesised that a self-renewing population of T cells, named stem cell-like memory T (TSCM) cells, are responsible for maintaining memory. However, it is not clear if the dynamics of TSCM cells in vivo are compatible with this hypothesis. To address this issue, we investigated the dynamics of TSCM cells under physiological conditions in humans in vivo using a multidisciplinary approach that combines mathematical modelling, stable isotope labelling, telomere length analysis, and cross-sectional data from vaccine recipients. We show that, unexpectedly, the average longevity of a TSCM clone is very short (half-life < 1 year, degree of self-renewal = 430 days): far too short to constitute a stem cell population. However, we also find that the TSCM population is comprised of at least 2 kinetically distinct subpopulations that turn over at different rates. Whilst one subpopulation is rapidly replaced (half-life = 5 months) and explains the rapid average turnover of the bulk TSCM population, the half-life of the other TSCM subpopulation is approximately 9 years, consistent with the longevity of the recall response. We also show that this latter population exhibited a high degree of self-renewal, with a cell residing without dying or differentiating for 15% of our lifetime. Finally, although small, the population was not subject to excessive stochasticity. We conclude that the majority of TSCM cells are not stem cell-like but that there is a subpopulation of TSCM cells whose dynamics are compatible with their putative role in the maintenance of T cell memory.

Quantitative proteomics analysis with iTRAQ in human lenses with nuclear cataracts of different axial lengths.

PubMed

Zhou, Haiyan; Yan, Hong; Yan, Weijia; Wang, Xinchuan; Ma, Yong; Wang, Jianping

2016-01-01

The goal of this study was to identify and quantify the differentially expressed proteins in human nuclear cataract with different axial lengths. Thirty-six samples of human lens nuclei with hardness grade III or IV were obtained during cataract surgery with extracapsular cataract extraction (ECCE). Six healthy transparent human lens nuclei were obtained from fresh healthy cadaver eyes during corneal transplantation surgery. The lens nuclei were divided into seven groups (six lenses in each group) according to the optic axis: Group A (mean axial length 28.7±1.5 mm; average age 59.8±1.9 years), Group B (mean axial length 23.0±0.4 mm; average age 60.3±2.5 years), Group C (mean axial length 19.9±0.5 mm; average age 55.1±2.5 years), Group D (mean axial length 28.7±1.4 mm; average age 58.0±4.0 years), Group E (mean axial length 23.0±0.3 mm; average age 56.9±4.2 years), and Group F (mean axial length 20.7±0.6 mm; average age 57.6±5.3 years). The six healthy transparent human lenses were included in a younger group with standard optic axes, Group G (mean axial length 23.0±0.5 mm; average age 34.7±4.2 years).Water-soluble, water-insoluble, and water-insoluble-urea-soluble protein fractions were extracted from the samples. The three-part protein fractions from the individual lenses were combined to form the total proteins of each sample. The proteomic profiles of each group were analyzed using 8-plex isobaric tagging for relative and absolute protein quantification (iTRAQ) labeling combined with two-dimensional liquid chromatography tandem mass spectrometry (2D-LC-MS/MS). The data were analyzed with ProteinPilot software for peptide matching, protein identification, and quantification. Differentially expressed proteins were validated with western blotting. We employed biological and technical replicates and selected the intersection of the two sets of results, which included 40 proteins. From the 40 proteins identified, six were selected as differentially expressed proteins closely related to axial length. The six proteins were gap junction alpha-3 protein, beta-crystallin B2, T-complex protein 1 subunit beta, gamma-enolase, pyruvate kinase isozymes M1/M2, and sorbitol dehydrogenase. Levels of beta-crystallin B2 expression were decreased in nuclear cataracts with longer axial length. The results of the mass spectrometric analysis were consistent with the western blot validation. The discovery of these differentially expressed proteins provides valuable clues for understanding the pathogenesis of axial-related nuclear cataract. The results indicate that beta-crystallin B2 (CRBB2) may be involved in axial-related nuclear cataract pathogenesis. Further studies are needed to investigate the correlation between CRBB2 and axial-related nuclear cataract.

Activation of the ALT pathway for telomere maintenance can affect other sequences in the human genome.

PubMed

Jeyapalan, Jennie N; Varley, Helen; Foxon, Jenny L; Pollock, Raphael E; Jeffreys, Alec J; Henson, Jeremy D; Reddel, Roger R; Royle, Nicola J

2005-07-01

Immortal human cells maintain telomere length by the expression of telomerase or through the alternative lengthening of telomeres (ALT). The ALT mechanism involves a recombination-like process that allows the rapid elongation of shortened telomeres. However, it is not known whether activation of the ALT pathway affects other sequences in the genome. To address this we have investigated, in ALT-expressing cell lines and tumours, the stability of tandem repeat sequences known to mutate via homologous recombination in the human germline. We have shown extraordinary somatic instability in the human minisatellite MS32 (D1S8) in ALT-expressing (ALT+) but not in normal or telomerase-expressing cell lines. The MS32 mutation frequency varied across 15 ALT+ cell lines and was on average 55-fold greater than in ALT- cell lines. The MS32 minisatellite was also highly unstable in three of eight ALT+ soft tissue sarcomas, indicating that somatic destabilization occurs in vivo. The MS32 mutation rates estimated for two ALT+ cell lines were similar to that seen in the germline. However, the internal structures of ALT and germline mutant alleles are very different, indicating differences in the underlying mutation mechanisms. Five other hypervariable minisatellites did not show elevated instability in ALT-expressing cell lines, indicating that minisatellite destabilization is not universal. The elevation of MS32 instability upon activation of the ALT pathway and telomere length maintenance suggests there is overlap between the underlying processes that may be tractable through analysis of the D1S8 locus.

Hybrid video-assisted thoracic surgery with segmental-main bronchial sleeve resection for non-small cell lung cancer.

PubMed

Li, Shuben; Chai, Huiping; Huang, Jun; Zeng, Guangqiao; Shao, Wenlong; He, Jianxing

2014-04-01

The purpose of the current study is to present the clinical and surgical results in patients who underwent hybrid video-assisted thoracic surgery with segmental-main bronchial sleeve resection. Thirty-one patients, 27 men and 4 women, underwent segmental-main bronchial sleeve anastomoses for non-small cell lung cancer between May 2004 and May 2011. Twenty-six (83.9%) patients had squamous cell carcinoma, and 5 patients had adenocarcinoma. Six patients were at stage IIB, 24 patients at stage IIIA, and 1 patient at stage IIIB. Secondary sleeve anastomosis was performed in 18 patients, and Y-shaped multiple sleeve anastomosis was performed in 8 patients. Single segmental bronchiole anastomosis was performed in 5 cases. The average time for chest tube removal was 5.6 days. The average length of hospital stay was 11.8 days. No anastomosis fistula developed in any of the patients. The 1-, 2-, and 3-year survival rates were 83.9%, 71.0%, and 41.9%, respectively. Hybrid video-assisted thoracic surgery with segmental-main bronchial sleeve resection is a complex technique that requires training and experience, but it is an effective and safe operation for selected patients.

Graph analysis of cell clusters forming vascular networks

NASA Astrophysics Data System (ADS)

Alves, A. P.; Mesquita, O. N.; Gómez-Gardeñes, J.; Agero, U.

2018-03-01

This manuscript describes the experimental observation of vasculogenesis in chick embryos by means of network analysis. The formation of the vascular network was observed in the area opaca of embryos from 40 to 55 h of development. In the area opaca endothelial cell clusters self-organize as a primitive and approximately regular network of capillaries. The process was observed by bright-field microscopy in control embryos and in embryos treated with Bevacizumab (Avastin), an antibody that inhibits the signalling of the vascular endothelial growth factor (VEGF). The sequence of images of the vascular growth were thresholded, and used to quantify the forming network in control and Avastin-treated embryos. This characterization is made by measuring vessels density, number of cell clusters and the largest cluster density. From the original images, the topology of the vascular network was extracted and characterized by means of the usual network metrics such as: the degree distribution, average clustering coefficient, average short path length and assortativity, among others. This analysis allows to monitor how the largest connected cluster of the vascular network evolves in time and provides with quantitative evidence of the disruptive effects that Avastin has on the tree structure of vascular networks.

Single-cell telomere-length quantification couples telomere length to meristem activity and stem cell development in Arabidopsis.

PubMed

González-García, Mary-Paz; Pavelescu, Irina; Canela, Andrés; Sevillano, Xavier; Leehy, Katherine A; Nelson, Andrew D L; Ibañes, Marta; Shippen, Dorothy E; Blasco, Maria A; Caño-Delgado, Ana I

2015-05-12

Telomeres are specialized nucleoprotein caps that protect chromosome ends assuring cell division. Single-cell telomere quantification in animals established a critical role for telomerase in stem cells, yet, in plants, telomere-length quantification has been reported only at the organ level. Here, a quantitative analysis of telomere length of single cells in Arabidopsis root apex uncovered a heterogeneous telomere-length distribution of different cell lineages showing the longest telomeres at the stem cells. The defects in meristem and stem cell renewal observed in tert mutants demonstrate that telomere lengthening by TERT sets a replicative limit in the root meristem. Conversely, the long telomeres of the columella cells and the premature stem cell differentiation plt1,2 mutants suggest that differentiation can prevent telomere erosion. Overall, our results indicate that telomere dynamics are coupled to meristem activity and continuous growth, disclosing a critical association between telomere length, stem cell function, and the extended lifespan of plants. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

A compact multi-bit flip-flop with smaller height implementation and metal-less intra-cell routing

NASA Astrophysics Data System (ADS)

Seo, Jaewoo; Jung, Jinwook; Shin, Youngsoo

2018-03-01

Multi-bit flip-ops (MBFFs) are widely used in modern circuit designs because of their lower power consumption and smaller footprint. However, conventional MBFFs have routability issues due to the dense intra-cell connections. Since many horizontal connections are populated in the typical MBFF layouts, metal-2 (M2) tracks are highly occupied inside the cell. Accordingly, routers cannot leverage the M2 tracks for inter-cell connections. The conventional MBFFs also show a limited impact on the cell area reduction. Since the cell area saving of an MBFF mainly comes from the clock driver sharing, the layouts of other ip-op modules remain almost the same. In this paper, we propose a compact MBFF with metal-less clock routing and smaller height implementation. To achieve a sparse population of M2 routing tracks, we vertically place MBFF modules and interconnect them using the poly layer. As a result, the wire length of M2 layer inside a cell is significantly reduced. We also propose the smaller cell height implementation for compact MBFF layouts. Assuming the default standard cell height of 9 tracks, we present a 6-track MBFF implementation and the glue logic which makes legal cell placement with the 9-track logic cells. Experiments with a few test circuits show that the number of routing grids having congestion overflow is reduced by 16% and 73%, on average, compared to the single-bit flip-op and conventional MBFF based designs, respectively. Total cell area is also reduced by 8% and 2%, on average, compared to the single-bit flip-op and conventional MBFF based designs, respectively.

A Comparative Analysis of Selected Mechanical Aspects of the Ice Skating Stride.

ERIC Educational Resources Information Center

Marino, G. Wayne

This study quantitatively analyzes selected aspects of the skating strides of above-average and below-average ability skaters. Subproblems were to determine how stride length and stride rate are affected by changes in skating velocity, to ascertain whether the basic assumption that stride length accurately approximates horizontal movement of the…

Organization of P, S, and Fe Inclusions in a Freshwater Magnetococcus

NASA Technical Reports Server (NTRS)

Cox, Lea; Popa Radu; Douglas, Susanne; Belz, Andrea; Nealson, Kenneth H.

2001-01-01

Magnetotactic bacteria are a heterogeneous group of motile, mainly aquatic procaryotes that align and swim along geomagnetic field lines. They are of interest to astrobiologists because of the magnetite crystals found in the Mars meteorite ALH84001 which share many characteristics with the magnetite produced intracellularly by magnetotactic bacteria. These bacteria are diverse morphologically, physiologically and phylogenetically, sharing a few key characteristics: 1) the presence of intracellular membrane-bound magnetic crystals (magnetosomes), usually but not always arranged in chains; 2) motility by means of flagella; and 3) microaerophillic or anaerobic physiology. The bilophotrichous (having two flagella bundles) magnetotactic cocci (MC) are ubiquitous in aquatic habitats but have proven extremely difficult to cultivate. Because only several marine strains have been isolated and grown in axenic culture, little is known about the physiology and the biogeochemical roles of the MC. We studied the composition and distribution of intracellular structures in an uncultured MC, designated ARB-1. To do this, a combination of light microscopy, environmental scanning electron microscopy (ESEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) were used. Cells of ARB-1 were separated from sediments collected from Baldwin Lake (Los Angeles Arboretum, Arcadia, CA). They are large spherical to oblate spheroidal Gram-negative cells, ranging from 1 to 4 micrometers along the maximum dimension, which is perpendicular to the direction of swimming. Cells have two large phosphorus-containing inclusions that comprise a large percentage of the cell volume. Many smaller sulfur inclusions are located at the convex end of the cell. Most of the cellular Fe is present in the magnetosomes. These may be arranged as a clump at the concave end of the cell, near the two flagella bundles, or as chains, or as both a clump and chains. The magnetosomes were identified as magnetite (Fe3O4) by selected area electron diffraction (SAED) and high resolution TEM. We saw a trend between cell size and organization of the magnetosomes. Smaller, more spherical cells were more likely to have chains than were larger, more oblate cells. This may indicate different populations of cells, or it may be attributed to variations in cell growth cycle. The size distribution (length) of magnetosomes in chains was similar to that of magnetosomes in clusters, except that there was a larger size range for clustered magnetosomes. Magnetosomes from ARB-1 cells average 82 nm in length. If plotted on a graph of length as a function of aspect ratio, they fall within the single domain region of the plot. If compared with the size distributions of magnetite from ALH84001 and magnetosomes from the cultured magnetotactic vibrio MV-1, the magnetites produced by ARB-1 cells are, on average, larger and have a wider range of aspect ratio. ARB-1 cells have a specific organization of the P, S, and Fe inclusions. The P inclusions always occupy the majority of the cell volume and separate the S inclusions from the disorganized clumps of magnetosomes and the flagella bundles. The P inclusions may contain polyphosphate, which could play several roles in motility, adaptation to stress, growth and division, buoyancy, and energy. The S inclusions might be a way to store S, a potential energy source, when the cells move from sulfide to oxygen zones. The consistency of P, S, and Fe organization in ARB-1 cells suggests that these inclusions have some specific and interactive functions.

Frequent pauses in Escherichia coli flagella elongation revealed by single cell real-time fluorescence imaging.

PubMed

Zhao, Ziyi; Zhao, Yifan; Zhuang, Xiang-Yu; Lo, Wei-Chang; Baker, Matthew A B; Lo, Chien-Jung; Bai, Fan

2018-05-14

The bacterial flagellum is a large extracellular protein organelle that extrudes from the cell surface. The flagellar filament is assembled from tens of thousands of flagellin subunits that are exported through the flagellar type III secretion system. Here, we measure the growth of Escherichia coli flagella in real time and find that, although the growth rate displays large variations at similar lengths, it decays on average as flagella lengthen. By tracking single flagella, we show that the large variations in growth rate occur as a result of frequent pauses. Furthermore, different flagella on the same cell show variable growth rates with correlation. Our observations are consistent with an injection-diffusion model, and we propose that an insufficient cytoplasmic flagellin supply is responsible for the pauses in flagellar growth in E. coli.

Quantifying Ciliary Dynamics during Assembly Reveals Step-wise Waveform Maturation in Airway Cells.

PubMed

Oltean, Alina; Schaffer, Andrew J; Bayly, Philip V; Brody, Steven L

2018-05-31

Motile cilia are essential for clearance of particulates and pathogens from airways. For effective transport, ciliary motor proteins and axonemal structures interact to generate the rhythmic, propulsive bending, but the mechanisms that produce a dynamic waveform remain incompletely understood. Biomechanical measures of human cilia motion and their relationships to cilia assembly are needed to illuminate the biophysics of normal cilia function, and to quantify dysfunction in ciliopathies. To these ends, we analyzed cilia motion from high-speed video microscopy of ciliated cells sampled from human lung airways compared to primary-culture cells that undergo ciliogenesis in vitro. Quantitative assessment of waveform parameters showed variations in waveform shape between individual cilia; however, general trends in waveform parameters emerged, associated with progression of cilia length and stage of differentiation. When cilia emerged from cultured cells, beat frequency was initially elevated, then fell and remained stable as cilia lengthened. In contrast, the average bending amplitude and the ability to generate force gradually increased and eventually approached values observed in ex vivo samples. Dynein arm motor proteins DNAH5, DNAH9, DNAH11, and DNAH6 were localized within specific regions of the axoneme in the ex vivo cells; however distinct stages of in vitro waveform development identified by biomechanical features were associated with the progressive movement of dyneins to the appropriate proximal or distal sections of the cilium. These observations suggest that the step-wise variation in waveform development during ciliogenesis is dependent on cilia length and potentially outer dynein arm assembly.

Plastic deformation in nanoscale gold single crystals and open-celled nanoporous gold

NASA Astrophysics Data System (ADS)

Lee, Dongyun; Wei, Xiaoding; Zhao, Manhong; Chen, Xi; Jun, Seong C.; Hone, James; Kysar, Jeffrey W.

2007-01-01

The results of two sets of experiments to measure the elastic-plastic behaviour of gold at the nanometre length scale are reported. One set of experiments was on free-standing nanoscale single crystals of gold, and the other was on free-standing nanoscale specimens of open-celled nanoporous gold. Both types of specimens were fabricated from commercially available leaf which was either pure Au or a Au/Ag alloy following by dealloying of the Ag. Mechanical testing specimens of a 'dog-bone' shape were fabricated from the leaf using standard lithographic procedures after the leaf had been glued onto a silicon wafer. The thickness of the gauge portion of the specimens was about 100 nm, the width between 250 nm and 300 nm and the length 7 µm. The specimens were mechanically loaded with a nanoindenter (MTS) at the approximate midpoint of the gauge length. The resulting force-displacement curve of the single crystal gold was serrated and it was evident that slip localization occurred on individual slip systems; however, the early stages of the plastic deformation occurred in a non-localized manner. The results of detailed finite element analyses of the specimen suggest that the critical resolved shear stress of the gold single crystal was as high as 135 MPa which would lead to a maximum uniaxial stress of about 500 MPa after several per cent strain. The behaviour of the nanoporous gold was substantially different. It exhibited an apparent elastic behaviour until the point where it failed in an apparently brittle manner, although it is assumed that plastic deformation occurred in the ligaments prior to failure. The average elastic stiffness of three specimens was measured to be Enp = 8.8 GPa and the stress at ultimate failure averaged 190 MPa for the three specimens tested. Scaling arguments suggest that the stress in the individual ligaments could approach the theoretical shear strength. Presented at the IUTAM Symposium on Plasticity at the Micron Scale, Technical University of Denmark, Copenhagen, Denmark.

Leukocyte Telomere Length in Major Depression: Correlations with Chronicity, Inflammation and Oxidative Stress - Preliminary Findings

PubMed Central

Wolkowitz, Owen M.; Mellon, Synthia H.; Epel, Elissa S.; Lin, Jue; Dhabhar, Firdaus S.; Su, Yali; Reus, Victor I.; Rosser, Rebecca; Burke, Heather M.; Kupferman, Eve; Compagnone, Mariana; Nelson, J. Craig; Blackburn, Elizabeth H.

2011-01-01

Background Depression is associated with an unusually high rate of aging-related illnesses and early mortality. One aspect of “accelerated aging” in depression may be shortened leukocyte telomeres. When telomeres critically shorten, as often occurs with repeated mitoses or in response to oxidation and inflammation, cells may die. Indeed, leukocyte telomere shortening predicts early mortality and medical illnesses in non-depressed populations. We sought to determine if leukocyte telomeres are shortened in Major Depressive Disorder (MDD), whether this is a function of lifetime depression exposure and whether this is related to putative mediators, oxidation and inflammation. Methodology Leukocyte telomere length was compared between 18 unmedicated MDD subjects and 17 controls and was correlated with lifetime depression chronicity and peripheral markers of oxidation (F2-isoprostane/Vitamin C ratio) and inflammation (IL-6). Analyses were controlled for age and sex. Principal Findings The depressed group, as a whole, did not differ from the controls in telomere length. However, telomere length was significantly inversely correlated with lifetime depression exposure, even after controlling for age (p<0.05). Average telomere length in the depressed subjects who were above the median of lifetime depression exposure (≥9.2 years' cumulative duration) was 281 base pairs shorter than that in controls (p<0.05), corresponding to approximately seven years of “accelerated cell aging.” Telomere length was inversely correlated with oxidative stress in the depressed subjects (p<0.01) and in the controls (p<0.05) and with inflammation in the depressed subjects (p<0.05). Conclusions These preliminary data indicate that accelerated aging at the level of leukocyte telomeres is proportional to lifetime exposure to MDD. This might be related to cumulative exposure to oxidative stress and inflammation in MDD. This suggest that telomere shortening does not antedate depression and is not an intrinsic feature. Rather, telomere shortening may progress in proportion to lifetime depression exposure. PMID:21448457

Environmental Enrichment Reveals Effects of Genotype on Hippocampal Spine Morphologies in the Mouse Model of Fragile X Syndrome

PubMed Central

Lauterborn, Julie C.; Jafari, Matiar; Babayan, Alex H.; Gall, Christine M.

2015-01-01

Fragile X Syndrome (FXS) and the Fmr1 knockout (KO) mouse model of this disorder exhibit abnormal dendritic spines in neocortex, but the degree of spine disturbances in hippocampus is not clear. The present studies tested if the mutation influences dendritic branching and spine measures for CA1 pyramidal cells in Fmr1 KO and wild-type (WT) mice provided standard or enriched environment (EE) housing. Automated measures from 3D reconstructions of green fluorescent protein (GFP)-labeled cells showed that spine head volumes were ∼40% lower in KOs when compared with WTs in both housing conditions. With standard housing, average spine length was greater in KOs versus WTs but there was no genotype difference in dendritic branching, numbers of spines, or spine length distribution. However, with EE rearing, significant effects of genotype emerged including greater dendritic branching in WTs, greater spine density in KOs, and greater numbers of short thin spines in KOs when compared with WTs. Thus, EE rearing revealed greater effects of the Fmr1 mutation on hippocampal pyramidal cell morphology than was evident with standard housing, suggesting that environmental enrichment allows for fuller appreciation of the impact of the mutation and better representation of abnormalities likely to be present in human FXS. PMID:24046080

Anti-biofilm efficacy of 100 MeV gold ion irradiated polycarbonate against Salmonella typhi

NASA Astrophysics Data System (ADS)

Joshi, R. P.; Hareesh, K.; Bankar, A.; Sanjeev, G.; Asokan, K.; Kanjilal, D.; Dahiwale, S. S.; Bhoraskar, V. N.; Dhole, S. D.

2017-12-01

Polycarbonate (PC) films were irradiated by 100 MeV gold (Au7+) ions and characterized to study changes in its optical, chemical, surface morphology and thermal properties. UV-Visible spectroscopic results revealed the decrease in the optical band gap of PC after ion irradiation due to chain scission mainly at the carbonyl group which is corroborated by Fourier Transform Infrared spectroscopic results. X-ray diffractogram study showed decrease in crystallinity of PC film after irradiation. Scanning electron microscopic results showed the micropores formation in PC which results in surface roughening. Differential scanning calorimetric results revealed decrease in glass transition temperature indicating the decrease in molecular weight of PC corroborated by rheometric studies. PC films irradiated by 100 MeV Au7+ ions showed increased anti-biofilm activity against the human pathogen, Salmonella typhi (S. typhi). Morphology of S. typhi was changed due to stress of Au7+ irradiated PC. Cells length was increased with increasing fluences. The average cell length, cell volume and surface area was increased significantly (P<0.05) with increasing ion fluences. Biofilm formation was inhibited ≈ 20% at lower fluence and 96% at higher fluence, which observed to be enhanced anti-biofilm activity in Au7+ irradiated PC.

Collective cell migration without proliferation: density determines cell velocity and wave velocity

NASA Astrophysics Data System (ADS)

Tlili, Sham; Gauquelin, Estelle; Li, Brigitte; Cardoso, Olivier; Ladoux, Benoît; Delanoë-Ayari, Hélène; Graner, François

2018-05-01

Collective cell migration contributes to embryogenesis, wound healing and tumour metastasis. Cell monolayer migration experiments help in understanding what determines the movement of cells far from the leading edge. Inhibiting cell proliferation limits cell density increase and prevents jamming; we observe long-duration migration and quantify space-time characteristics of the velocity profile over large length scales and time scales. Velocity waves propagate backwards and their frequency depends only on cell density at the moving front. Both cell average velocity and wave velocity increase linearly with the cell effective radius regardless of the distance to the front. Inhibiting lamellipodia decreases cell velocity while waves either disappear or have a lower frequency. Our model combines conservation laws, monolayer mechanical properties and a phenomenological coupling between strain and polarity: advancing cells pull on their followers, which then become polarized. With reasonable values of parameters, this model agrees with several of our experimental observations. Together, our experiments and model disantangle the respective contributions of active velocity and of proliferation in monolayer migration, explain how cells maintain their polarity far from the moving front, and highlight the importance of strain-polarity coupling and density in long-range information propagation.

Polymer-based solar cells having an active area of 1.6 cm{sup 2} fabricated via spray coating

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

Scarratt, N. W.; Griffin, J.; Zhang, Y.

We demonstrate the fabrication of polymer solar cells in which both a PEDOT:PSS hole transport and a PCDTBT:PC{sub 71}BM photoactive layer are deposited by spray-casting. Two device geometries are explored, with devices having a pixel area of 165 mm{sup 2} attaining a power conversion efficiency of 3.7%. Surface metrology indicates that the PEDOT:PSS and PCDTBT:PC{sub 71}BM layers have a roughness of 2.57 nm and 1.18 nm over an area of 100 μm{sup 2}. Light beam induced current mapping reveals fluctuations in current generation efficiency over length-scales of ∼2 mm, with the average photocurrent being 75% of its maximum value.

Effect of short wavelength illumination on the characteristic bulk diffusion length in ribbon silicon solar cells

NASA Technical Reports Server (NTRS)

Ho, C. T.; Mathias, J. D.

1981-01-01

The influence of short wavelength light on the characteristic bulk minority carrier diffusion length of the ribbon silicon photovoltaic cell has been investigated. We have measured the intensity and wavelength dependence of the diffusion length in an EFG ribbon cell, and compared it with a standard Czochralski grown silicon cell. While the various short wavelength illuminations have shown no influence on the diffusion length in the CZ cell, the diffusion lengths in the ribbon cell exhibit a strong dependence on the volume generation rate as well as on the wavelength of the superimposed lights. We have concluded that the trap-filling phenomenon at various depths in the bulk neutral region of the cell is consistent with the experimental observation.

Transport Imaging of Multi-Junction and CIGS Solar Cell Materials

DTIC Science & Technology

2011-12-01

solar cells start with the material charge transport parameters, namely the charge mobility, lifetime and diffusion length . It is the goal of...every solar cell manufacturer to maintain high carrier lifetime so as to realize long diffusion lengths . Long diffusion lengths ensure that the charges...Thus, being able to accurately determine the diffusion length of any solar cell material proves advantageous by providing insights

Silicon solar cell process development, fabrication and analysis

NASA Technical Reports Server (NTRS)

Yoo, H. I.; Iles, P. A.; Leung, D. C.

1981-01-01

Solar cells were fabricated from EFG ribbons dendritic webs, cast ingots by heat exchanger method, and cast ingots by ubiquitous crystallization process. Baseline and other process variations were applied to fabricate solar cells. EFG ribbons grown in a carbon-containing gas atmosphere showed significant improvement in silicon quality. Baseline solar cells from dendritic webs of various runs indicated that the quality of the webs under investigation was not as good as the conventional CZ silicon, showing an average minority carrier diffusion length of about 60 um versus 120 um of CZ wafers. Detail evaluation of large cast ingots by HEM showed ingot reproducibility problems from run to run and uniformity problems of sheet quality within an ingot. Initial evaluation of the wafers prepared from the cast polycrystalline ingots by UCP suggested that the quality of the wafers from this process is considerably lower than the conventional CZ wafers. Overall performance was relatively uniform, except for a few cells which showed shunting problems caused by inclusions.

Career Length and Performance Among Professional Baseball Players Returning to Play After Hip Arthroscopy.

PubMed

Frangiamore, Salvatore J; Mannava, Sandeep; Briggs, Karen K; McNamara, Shannen; Philippon, Marc J

2018-05-01

Hip arthroscopy has been shown to be effective for management of symptomatic femoroacetabular impingement (FAI) in professional athletes; however, it is unclear how hip arthroscopy affects career length and performance when professional baseball players return to play. To determine the career length, performance, and return-to-play rates of professional baseball players after undergoing arthroscopy for symptomatic FAI. Case series; Level of evidence, 4. Forty-four professional baseball players (51 hips) underwent hip arthroscopy for FAI between 2000 and 2015 by a single surgeon. Data were retrieved for each player from MLB.com , MiLB.com , Baseballreference.com , and individual team websites. Age, surgical procedure, and intraoperative findings were also used in analysis. Return to play was defined as playing in a preseason or regular season major or minor league game after arthroscopy. Career length was measured as total years played before and after arthroscopy. Performance measures included earned run average for pitchers, batting average for position players, and games played for all players. Of the 44 players, there were 21 pitchers and 23 position players. Ninety-five percent (n = 42) were able to return to professional baseball after hip arthroscopy. The mean career length for all players was 9.5 years. The mean career length after return to play was 3.6 seasons (range, 1-14 seasons). Pitchers had a mean career length of 8.7 years (3.3 after surgery), and position players averaged a career length of 10 years (3.9 after surgery). There were no differences in performance measures between preinjury and postoperative values. Professional baseball players undergoing hip arthroscopy for FAI returned to sport and had similar performance as they did before injury. The average career length was 9.5 years. In our study cohort, more pitchers than position players underwent hip arthroscopy. Hip arthroscopy appears to be an effective surgical intervention, allowing for return to play after complete recovery.

Ag nanoparticles-decorated ZnO nanorod array on a mechanical flexible substrate with enhanced optical and antimicrobial properties

NASA Astrophysics Data System (ADS)

Chen, Yi; Tse, Wai Hei; Chen, Longyan; Zhang, Jin

2015-03-01

Heteronanostructured zinc oxide nanorod (ZnO NR) array are vertically grown on polydimethylsiloxane (PDMS) through a hydrothermal method followed by an in situ deposition of silver nanoparticles (Ag NPs) through a photoreduction process. The Ag-ZnO heterostructured nanorods on PDMS are measured with an average diameter of 160 nm and an average length of 2 μm. ZnO NRs measured by high-resolution transmission electron microscope (HRTEM) shows highly crystalline with a lattice fringe of 0.255 nm, which corresponds to the (0002) planes in ZnO crystal lattice. The average diameter of the Ag NPs in situ deposited on the ZnO NRs is estimated at 22 ± 2 nm. As compared to the bare ZnO NRs, the heterostructured Ag-ZnO nanorod array shows enhanced ultraviolet (UV) absorption at 440 nm, and significant emission in the visible region (λem = 542 nm). In addition, the antimicrobial efficiency of Ag-ZnO heterostructured nanorod array shows obvious improvement as compared to bare ZnO nanorod array. The cytotoxicity of ZnO nanorod array with and without Ag NPs was studied by using 3 T3 mouse fibroblast cell line. No significant toxic effect is imposed on the cells.

Ag nanoparticles-decorated ZnO nanorod array on a mechanical flexible substrate with enhanced optical and antimicrobial properties.

PubMed

Chen, Yi; Tse, Wai Hei; Chen, Longyan; Zhang, Jin

2015-01-01

Heteronanostructured zinc oxide nanorod (ZnO NR) array are vertically grown on polydimethylsiloxane (PDMS) through a hydrothermal method followed by an in situ deposition of silver nanoparticles (Ag NPs) through a photoreduction process. The Ag-ZnO heterostructured nanorods on PDMS are measured with an average diameter of 160 nm and an average length of 2 μm. ZnO NRs measured by high-resolution transmission electron microscope (HRTEM) shows highly crystalline with a lattice fringe of 0.255 nm, which corresponds to the (0002) planes in ZnO crystal lattice. The average diameter of the Ag NPs in situ deposited on the ZnO NRs is estimated at 22 ± 2 nm. As compared to the bare ZnO NRs, the heterostructured Ag-ZnO nanorod array shows enhanced ultraviolet (UV) absorption at 440 nm, and significant emission in the visible region (λem = 542 nm). In addition, the antimicrobial efficiency of Ag-ZnO heterostructured nanorod array shows obvious improvement as compared to bare ZnO nanorod array. The cytotoxicity of ZnO nanorod array with and without Ag NPs was studied by using 3 T3 mouse fibroblast cell line. No significant toxic effect is imposed on the cells.

Mathematical models of tumor heterogeneity and drug resistance

NASA Astrophysics Data System (ADS)

Greene, James

In this dissertation we develop mathematical models of tumor heterogeneity and drug resistance in cancer chemotherapy. Resistance to chemotherapy is one of the major causes of the failure of cancer treatment. Furthermore, recent experimental evidence suggests that drug resistance is a complex biological phenomena, with many influences that interact nonlinearly. Here we study the influence of such heterogeneity on treatment outcomes, both in general frameworks and under specific mechanisms. We begin by developing a mathematical framework for describing multi-drug resistance to cancer. Heterogeneity is reflected by a continuous parameter, which can either describe a single resistance mechanism (such as the expression of P-gp in the cellular membrane) or can account for the cumulative effect of several mechanisms and factors. The model is written as a system of integro-differential equations, structured by the continuous "trait," and includes density effects as well as mutations. We study the limiting behavior of the model, both analytically and numerically, and apply it to study treatment protocols. We next study a specific mechanism of tumor heterogeneity and its influence on cell growth: the cell-cycle. We derive two novel mathematical models, a stochastic agent-based model and an integro-differential equation model, each of which describes the growth of cancer cells as a dynamic transition between proliferative and quiescent states. By examining the role all parameters play in the evolution of intrinsic tumor heterogeneity, and the sensitivity of the population growth to parameter values, we show that the cell-cycle length has the most significant effect on the growth dynamics. In addition, we demonstrate that the agent-based model can be approximated well by the more computationally efficient integro-differential equations, when the number of cells is large. The model is closely tied to experimental data of cell growth, and includes a novel implementation of transition rates as a function of global density. Finally, we extend the model of cell-cycle heterogeneity to include spatial variables. Cells are modeled as soft spheres and exhibit attraction/repulsion/random forces. A fundamental hypothesis is that cell-cycle length increases with local density, thus producing a distribution of observed division lengths. Apoptosis occurs primarily through an extended period of unsuccessful proliferation, and the explicit mechanism of the drug (Paclitaxel) is modeled as an increase in cell-cycle duration. We show that the distribution of cell-cycle lengths is highly time-dependent, with close time-averaged agreement with the distribution used in the previous work. Furthermore, survival curves are calculated and shown to qualitatively agree with experimental data in different densities and geometries, thus relating the cellular microenvironment to drug resistance.

Study of Natural Fiber Breakage during Composite Processing

NASA Astrophysics Data System (ADS)

Quijano-Solis, Carlos Jafet

Biofiber-thermoplastic composites have gained considerable importance in the last century. To provide mechanical reinforcement to the polymer, fibers must be larger than a critical aspect ratio (length-to-width ratio). However, biofibers undergo breakage in length or width during processing, affecting their final aspect ratio in the composites. In this study, influence on biofiber breakage by factors related to processing conditions, fiber morphology and the flow type was investigated through: a) experiments using an internal mixer, a twin-screw extruder (TSE) or a capillary rheometer; and b) a Monte Carlo computer simulation. Composites of thermomechanical fibers of aspen or wheat straw mixed with polypropylene were studied. Internal mixer experiments analyzed wheat straw and two batches of aspen fibers, named AL and AS. AL fibers had longer average length. Processing variables included the temperature, rotors speed and fiber concentration. TSE experiments studied AL and AS fiber composites under various screws speeds, temperatures and feeding rates of the polymer and fibers. Capillary rheometers experiments determined AL fiber breakage in shear and elongational flows for composites processed at different concentrations, temperatures, and strain rates. Finally, the internal mixer experimental results where compared to Monte Carlo simulation predictions. The simulation focused on fiber length breakage due to fiber-polymer interactions. Internal mixer results showed that final fiber average length depended almost solely on processing conditions while final fiber average width depended on both processing conditions and initial fiber morphology. In the TSE, processing conditions as well as initial fiber length influenced final average length. TSE results showed that the fiber concentration regime seems to influence the effect of processing variables on fiber breakage. Capillary rheometer experiments demonstrated that biofiber breakage happens in both elongational and shear flows. In some cases, percentage of biofiber breakage in elongational flow is higher. In general, simulation predictions of final average lengths were in good agreement with experiments, indicating the importance of fiber-polymer interactions on fiber breakage. The largest discrepancies were obtained at higher fiber concentration composites; these differences might be resolved, in future simulations, by including the effect of fiber-fiber interactions.

Development of the Statocyst in the Freshwater Snail Biomphalaria Glabrata (Pulmonata, Basommatophora)

NASA Technical Reports Server (NTRS)

Gao, Wenyuan; Wiederhold, Michael; Hejl, Robert

1997-01-01

The development of the statocyst of the freshwater snail Biomphalaria glabrata has been examined from embryo to adult. Special emphasis was put on the growth of the statoconia in the statocysts. In the statocysts of embryonic snails (90-120 h after oviposition) there is not a single statolith but an average of 40-50 statoconia per statocyst. The number of statoconia increases to 385-400 when the snails reach a shell diameter of 4 mm and remains relatively constant thereafter, irrespective of shell size. Small statoconia are found in supporting cells, which suggests that the statoconia are produced within these cells. The average diameter of statoconia and the total mass of statoconia increase with increasing shell diameter. The average number of large statoconia (diameter greater than 7 micrometers) per statocyst continues to increase from 2 to 10 mm animals while the number of small ones (diameter less than 4 micrometers) initially rises and then decreases after 4 mm. These results demonstrate continuous growth of the statoconia in the cyst lumen of Biomphalaria. The single statoconia vibrate in a regular pattern in vivo, indicating beating of the statocyst cilia. The statoconia sink under the influence of gravity to load and stimulate receptor cells which are at the bottom. The length of cilia and the size of statocyst gradually increase as the animal grows. However, the increase in the volume of the statocyst is relatively small compared with the increase in body weight during normal development.

Quantifying nonergodicity in nonautonomous dissipative dynamical systems: An application to climate change

NASA Astrophysics Data System (ADS)

Drótos, Gábor; Bódai, Tamás; Tél, Tamás

2016-08-01

In nonautonomous dynamical systems, like in climate dynamics, an ensemble of trajectories initiated in the remote past defines a unique probability distribution, the natural measure of a snapshot attractor, for any instant of time, but this distribution typically changes in time. In cases with an aperiodic driving, temporal averages taken along a single trajectory would differ from the corresponding ensemble averages even in the infinite-time limit: ergodicity does not hold. It is worth considering this difference, which we call the nonergodic mismatch, by taking time windows of finite length for temporal averaging. We point out that the probability distribution of the nonergodic mismatch is qualitatively different in ergodic and nonergodic cases: its average is zero and typically nonzero, respectively. A main conclusion is that the difference of the average from zero, which we call the bias, is a useful measure of nonergodicity, for any window length. In contrast, the standard deviation of the nonergodic mismatch, which characterizes the spread between different realizations, exhibits a power-law decrease with increasing window length in both ergodic and nonergodic cases, and this implies that temporal and ensemble averages differ in dynamical systems with finite window lengths. It is the average modulus of the nonergodic mismatch, which we call the ergodicity deficit, that represents the expected deviation from fulfilling the equality of temporal and ensemble averages. As an important finding, we demonstrate that the ergodicity deficit cannot be reduced arbitrarily in nonergodic systems. We illustrate via a conceptual climate model that the nonergodic framework may be useful in Earth system dynamics, within which we propose the measure of nonergodicity, i.e., the bias, as an order-parameter-like quantifier of climate change.

Embryonic and larval development in barfin flounder Verasper moseri (Jordan and Gilbert)

NASA Astrophysics Data System (ADS)

Du, Rongbin; Wang, Yongqiang; Jiang, Haibin; Liu, Liming; Wang, Maojian; Li, Tianbao; Zhang, Shubao

2010-01-01

Broodstock of Verasper moseri (Jordan and Gilbert) aged 3-4 years old were selected, and reinforced cultivation was conducted to promote maturation under controlled water temperature and photoperiod conditions. Fertilized eggs were obtained by artificial fertilization, and the development of embryos, larvae and juveniles was observed continuously. The results showed that the fertilized eggs of V. moseri were spherical, with transparent yolk and homogeneous bioplasm, and had no oil globule inside. The average diameter of the eggs was 1.77±0.02 mm. The eggs of V. moseri were buoyant in water with salinity above 35. The cleavage type was typical discoidal. Young pigment cells appeared when olfactory plates began to form. Hatching occurred at 187 h after fertilization at a water temperature of 8.5°C. The newly hatched larvae, floating on the water surface, were transparent with an average total length of 4.69±0.15 mm. During the cultivation period, when the water temperature was raised from 9 to 14.5°C, 4-day old larvae showed more melanophores on the body surface, making the larvae gray in color. The pectoral fins began to develop, which enabled the larvae to swim horizontally and in a lively manner. On days 7-8, the digestive duct formed. The yolk sac was small and black. The yolk sac was absorbed on day 11. Larvae took food actively, and body length and body height clearly increased. The rudiments of dorsal and anal fin pterygiophores were discernible and caudal fin ray elements formed on day 19. On day 24, the larval notochord flexed upwards, and the rays of unpaired fins began to differentiate. Pigment cells converged on the dorsal and anal fin rays, and the mastoid teeth on the mandible appeared. On day 29, the left eyes of juveniles began to move upwards. Depigmentation began in some juveniles and they became sandy brown in color on day 37. Most juveniles began to settle on the bottom of the tank. The left eyes of juveniles migrated completely to the right side on day 50, when the average body length attained 2.5±0.18 cm, and juveniles accomplished metamorphosis to young. The embryonic and larval characters of several flounder species are compared.

Noise reduction in the intracellular pom1p gradient by a dynamic clustering mechanism.

PubMed

Saunders, Timothy E; Pan, Kally Z; Angel, Andrew; Guan, Yinghua; Shah, Jagesh V; Howard, Martin; Chang, Fred

2012-03-13

Chemical gradients can generate pattern formation in biological systems. In the fission yeast Schizosaccharomyces pombe, a cortical gradient of pom1p (a DYRK-type protein kinase) functions to position sites of cytokinesis and cell polarity and to control cell length. Here, using quantitative imaging, fluorescence correlation spectroscopy, and mathematical modeling, we study how its gradient distribution is formed. Pom1p gradients exhibit large cell-to-cell variability, as well as dynamic fluctuations in each individual gradient. Our data lead to a two-state model for gradient formation in which pom1p molecules associate with the plasma membrane at cell tips and then diffuse on the membrane while aggregating into and fragmenting from clusters, before disassociating from the membrane. In contrast to a classical one-component gradient, this two-state gradient buffers against cell-to-cell variations in protein concentration. This buffering mechanism, together with time averaging to reduce intrinsic noise, allows the pom1p gradient to specify positional information in a robust manner. Copyright © 2012 Elsevier Inc. All rights reserved.

Shaping the shoot: the relative contribution of cell number and cell shape to variations in internode length between parent and hybrid apple trees.

PubMed

Ripetti, V; Escoute, J; Verdeil, J L; Costes, E

2008-01-01

Genetic control of plant size and shape is a promising perspective, particularly in fruit trees, in order to select desirable genotypes. A recent study on architectural traits in an apple progeny showed that internode length was a highly heritable character. However, few studies have been devoted to internode cellular patterning in dicotyledonous stems, and the interplay between the two elementary cell processes that contribute to their length, i.e. cell division and elongation, is not fully understood. The present study aimed at unravelling their contributions in the genetic variation of internode length in a selection of F(1) and parent genotypes of apple tree, by exploring the number of cells and cell shape within mature internodes belonging to the main axes. The results highlighted that both the variables were homogeneous in samples collected either along a sagital line or along the pith width, and suggest that cell lengthening was homogeneous during internode development. They allowed the total number of cells to be estimated on the internode scale and opened up new perspectives for simplifying tissue sampling procedures for further investigations. Differences in internode length were observed between the genotypes, in particular between the parents, and partly resulted from a compensation between cell number and cell length. However, genetic variations in internode length primarily involved the number of cells, while cell length was more secondary. These results argue for an interplay between cellular and organismal control of internode shape that may involve the rib meristem.

Co-Ordination Compounds as Sensitizers for Percussion Cap Compositions

DTIC Science & Technology

1949-01-01

table. TABLE III Time elapsed (hours) Mixture Sensitivity* (inches/ £ lb.) Ballistic Pendulum » Power coefficient C. of V. of trace lengths...dimension C = 50-52. The power co-efficient is obtained by dividing the average trace length for 10 of the caps under trial by the average trace ...resulting in a high C. of V. The trace lengths as measured were as follows: 8.25, 8.30, 4.55, 10.65, 9.55, 9.0C, 8.46, 8.42, 8.21, 8.34 inches. The

A Motor-Driven Mechanism for Cell-Length Sensing

PubMed Central

Rishal, Ida; Kam, Naaman; Perry, Rotem Ben-Tov; Shinder, Vera; Fisher, Elizabeth M.C.; Schiavo, Giampietro; Fainzilber, Mike

2012-01-01

Summary Size homeostasis is fundamental in cell biology, but it is not clear how large cells such as neurons can assess their own size or length. We examined a role for molecular motors in intracellular length sensing. Computational simulations suggest that spatial information can be encoded by the frequency of an oscillating retrograde signal arising from a composite negative feedback loop between bidirectional motor-dependent signals. The model predicts that decreasing either or both anterograde or retrograde signals should increase cell length, and this prediction was confirmed upon application of siRNAs for specific kinesin and/or dynein heavy chains in adult sensory neurons. Heterozygous dynein heavy chain 1 mutant sensory neurons also exhibited increased lengths both in vitro and during embryonic development. Moreover, similar length increases were observed in mouse embryonic fibroblasts upon partial downregulation of dynein heavy chain 1. Thus, molecular motors critically influence cell-length sensing and growth control. PMID:22773964

End-compensated magnetostatic cavity for polarized 3He neutron spin filters.

PubMed

McIver, J W; Erwin, R; Chen, W C; Gentile, T R

2009-06-01

We have expanded upon the "Magic Box" concept, a coil driven magnetic parallel plate capacitor constructed out of mu-metal, by introducing compensation sections at the ends of the box that are tuned to limit end-effects similar to those of short solenoids. This ability has reduced the length of the magic box design without sacrificing any loss in field homogeneity, making the device far more applicable to the often space limited neutron beam line. The appeal of the design beyond affording longer polarized 3He lifetimes is that it provides a vertical guide field, which facilitates neutron spin transport for typical polarized beam experiments. We have constructed two end-compensated magic boxes of dimensions 28.4 x 40 x 15 cm3 (length x width x height) with measured, normalized volume-averaged transverse field gradients ranging from 3.3 x 10(-4) to 6.3 x 10(-4) cm(-1) for cell sizes ranging from 8.1 x 6.0 to 12.0 x 7.9 cm2 (diameter x length), respectively.

[Microsurgical anatomy importance of A1-anterior communicating artery complex].

PubMed

Monroy-Sosa, Alejandro; Pérez-Cruz, Julio César; Reyes-Soto, Gervith; Delgado-Hernández, Carlos; Macías-Duvignau, Mario Alberto; Delgado-Reyes, Luis

2013-01-01

The anterior cerebral artery originates from the bifurcation of the internal carotid artery lateral to the optic chiasm, then joins with its contralateral counterpart via the anterior communicating artery. A1-anterior communicating artery complex is the most frequent anatomical variants and is the major site of aneurysms between 30 to 37%. Know the anatomy microsurgical, variants anatomical and importance of complex precommunicating segment-artery anterior communicating in surgery neurological of the pathology vascular, mainly aneurysms, in Mexican population. The study was performed in 30 brains injected. Microanatomy was studied (length and diameter) of A1-anterior communicating artery complex and its variants. 60 segments A1, the average length of left side was 11.35 mm and 11.84 mm was right. The average diameter of left was 1.67 mm and the right was 1.64 mm. The average number of perforators on the left side was 7.9 and the right side was 7.5. Anterior communicating artery was found in 29 brains of the optic chiasm, its course depended on the length of the A1 segment. The average length of the segment was 2.84 mm, the average diameter was 1.41 mm and the average number of perforators was 3.27. A1-anterior communicating artery complex variants were found in 18 (60%) and the presence of two blister-like aneurysms. It is necessary to understand the A1-anterior communicating artery complex microanatomy of its variants to have a three-dimensional vision during aneurysm surgery.

The use of telomere length as a predictive biomarker for injury prognosis in juvenile rats following a concussion/mild traumatic brain injury.

PubMed

Hehar, Harleen; Mychasiuk, Richelle

2016-03-01

Telomeres were originally believed to be passive players in cellular replication, but recent research has highlighted their more active role in epigenetic patterning and promotion of cellular growth and survival. Furthermore, literature demonstrates that telomere length (TL) is responsive to environmental manipulations such as prenatal stress and dietary programming. As the search for a prognostic biomarker of concussion has had limited success, this study sought to examine whether or not telomere length (TL) could be an efficacious predictor of symptom severity in juvenile rats following concussion. Rats from four distinct experimental groups (caloric restriction (CR), high fat diet (HFD), exercise (EX), and standard controls (STD)) received a mild traumatic brain injury (mTBI)/concussion and were then subjected to a behavioural test battery. The test battery was scored and the animals were categorized as poor, average, or good, based on their performance on the 6 tests examined. Skin cells (from ear notch samples) were taken 17days post-injury and DNA was extracted for telomere length analysis. Ear notch skin cell TL was highly correlated with brain tissue TL for a given individual. Animals in the CR and EX cohorts had significantly longer telomeres, while animals in the HFD cohort had significantly shorter telomeres, when compared to controls. The mTBI/concussion reduced TL in all cohorts except the EX group. A significant linear relationship was found between TL and performance on the behavioural test battery, whereby shorter telomeres were associated with poorer performance and longer telomeres with better performance. As performance on the test battery is linked to symptom severity, this study found TL to be a reasonable tool for concussion prognosis. Future studies with human populations should examine the validity of TL in peripheral cells, as a predictor of concussion pathology. Copyright © 2015 Elsevier Inc. All rights reserved.

Diffusion length variation and proton damage coefficients for InP/In(x)Ga(1-x)As/GaAs solar cells

NASA Technical Reports Server (NTRS)

Jain, R. K.; Weinberg, I.; Flood, D. J.

1993-01-01

Indium phosphide solar cells are more radiation resistant than gallium arsenide and silicon solar cells, and their growth by heteroepitaxy offers additional advantages leading to the development of lighter, mechanically strong and cost-effective cells. Changes in heteroepitaxial InP cell efficiency under 0.5 and 3 MeV proton irradiations are explained by the variation in the minority-carrier diffusion length. The base diffusion length versus proton fluence is calculated by simulating the cell performance. The diffusion length damage coefficient K(L) is plotted as a function of proton fluence.

Spatiotemporal Variables of Able-bodied and Amputee Sprinters in Men's 100-m Sprint.

PubMed

Hobara, H; Kobayashi, Y; Mochimaru, M

2015-06-01

The difference in world records set by able-bodied sprinters and amputee sprinters in the men's 100-m sprint is still approximately 1 s (as of 28 March 2014). Theoretically, forward velocity in a 100-m sprint is the product of step frequency and step length. The goal of this study was to examine the hypothesis that differences in the sprint performance of able-bodied and amputee sprinters would be due to a shorter step length rather than lower step frequency. Men's elite-level 100-m races with a total of 36 able-bodied, 25 unilateral and 17 bilateral amputee sprinters were analyzed from the publicly available internet broadcasts of 11 races. For each run of each sprinter, the average forward velocity, step frequency and step length over the whole 100-m distance were analyzed. The average forward velocity of able-bodied sprinters was faster than that of the other 2 groups, but there was no significant difference in average step frequency among the 3 groups. However, the average step length of able-bodied sprinters was significantly longer than that of the other 2 groups. These results suggest that the differences in sprint performance between 2 groups would be due to a shorter step length rather than lower step frequency. © Georg Thieme Verlag KG Stuttgart · New York.

Fragment Length of Circulating Tumor DNA.

PubMed

Underhill, Hunter R; Kitzman, Jacob O; Hellwig, Sabine; Welker, Noah C; Daza, Riza; Baker, Daniel N; Gligorich, Keith M; Rostomily, Robert C; Bronner, Mary P; Shendure, Jay

2016-07-01

Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA) may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134-144 bp vs. 167 bp, respectively). Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132-145 bp vs. 165 bp, respectively). Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA.

Similar Hydrodynamic and Morphological Changes in the Aqueous Humor Outflow Pathway after Washout and Y27632 Treatment in Monkey Eyes

PubMed Central

Lu, Zhaozeng; Zhang, Yuyan; Freddo, Thomas F.; Gong, Haiyan

2011-01-01

Our previous studies in bovine eyes demonstrated that the structural correlate to the increase in outflow facility after either Rho-kinase inhibitor Y-27632 (Y27) treatment or washout appeared to be separation between the juxtacanalicular tissue (JCT) and inner wall (IW) of the aqueous plexus, the bovine equivalent of Schlemm's canal (SC). While these findings suggest that Y27 and washout may increase outflow facility through a similar mechanism, the anatomy of bovine outflow pathway differs considerably from both the human and monkey outflow pathway; however, only the human eye does not exhibit washout. In light of this, we compared the effects of Y27 and washout on outflow facility, hydrodynamic patterns of outflow, and the morphology of the IW and JCT in monkey eyes, given that their anatomy is closer to human eyes. Twelve freshly enucleated monkey eyes were used in this study. Eyes were perfused with Dulbecco's PBS containing 5.5 mM glucose (GPBS) to establish a baseline facility at 15 mmHg. Four eyes were perfused for a short-duration (30 min) as a control, 4 eyes for a long-duration (180 min) to induce washout, and 4 eyes with GPBS+50 μM Y27 for 30 min. All eyes were then perfused with fluorescent microspheres (0.5μm; 0.002%) to label the hydrodynamic patterns of outflow and then perfusion-fixed. Confocal images of frontal sections were taken along the IW of SC. The total length (TL) and the tracer decorated length (FL) of the IW were measured to calculate the average percent effective filtration length (PEFL=FL/TL). Sections with SC were examined by light and electron microscopy. The TL of the IW and the length exhibiting separation (SL) in the JCT were measured to calculate the average percent separation length (PSL= SL/TL). Outflow facility increased 149.2% (p<0.01) from baseline after washout during long-duration perfusion, and 114.9% (p=0.004) after Y27 treatment, but did not change significantly after short-duration perfusion in control eyes (p=0.46). Distribution of the tracer labeling appeared punctate along the IW of control eyes, while a more uniform pattern was observed after washout and Y27 treatment. PEFL in washout (83.4±2.1%) and Y27 treated eyes (82.5±1.6%) was 3.4-fold larger compared to controls (24.2±4.2%, P<0.001). The JCT appeared distended with loss of connections between JCT cells and between JCT cells and their extracelluar matrix in eyes with washout or after Y-27 treatment. PSL in the JCT was 2.3-fold larger in washout eyes (77.4±3.3%) and 2.2-fold larger in Y27 treated eyes (75.2±5.3%) versus controls (33.5±5.3%, p=0.001). Significant positive correlations were found between outflow facility and PEFL, facility and PSL and between PEFL and PSL. Our data demonstrated that similar hydrodynamic and morphological changes occurred in the aqueous humor outflow pathway of monkey eyes after induction of washout and Y27 treatment. Both Y27 and washout increase outflow facility by redistributing aqueous outflow through a larger area in the JCT. These hydrodynamic changes are likely driven by morphologic changes associated with a decrease in cell-cell and cell-matrix connections in the JCT. PMID:21669200

Assessment by bioimpedance of forearm cell mass: a new approach to calibration.

PubMed

Pietrobelli, A; Nuñez, C; Zingaretti, G; Battistini, N; Morini, P; Wang, Z M; Yasumura, S; Heymsfield, S B

2002-08-01

Changes in skeletal muscle mass are involved in several important clinical disorders including sarcopenia and obesity. Unlike body fat, skeletal muscle is difficult to quantify in vivo, particularly without highly specialized equipment. The present study had a two-fold aim: to develop a regional (40)K counter for non-invasively estimating cell mass in the arm, mainly skeletal muscle cell mass, without radiation exposure; and to test the hypothesis that cell mass in the arm is highly correlated with electrical impedance after adjusting for the arm's length. Forearm cell mass was estimated using a rectangular lead-shielded (40)K counter with 4-NaI crystals; impedance of the arm was measured at multiple frequencies using a segmental bioimpedance analysis (BIA) system. The system's within- and between-day coefficient of variation (CV) for (40)K-derived elemental potassium averaged 1.8+/-1.3 and 5.8+/-1.2%, respectively. The corresponding BIA system's CVs were 1.0+/-0.4 and 2.1+/-1.0%, respectively. Participants in the study were 15 healthy adults (eight females, seven males; age 39+/-2.8 y, BMI 22.9+/-4.5 kg/m(2)). The right arm's K (5.2+/-1.7 g) was highly correlated with length-adjusted impedance (r(2)=0.81, 0.82, and 0.83 for 5, 50 and 300 kHz, respectively; all P<0.001); multiple regression analysis showed no additional improvement by adding age or sex to the prediction models. These results demonstrate the feasibility of calibrating BIA-measured electrical properties of the arm against estimates of arm cell mass, mainly of skeletal muscle, obtained by regional (40)K counting. This simple and practical approach should facilitate the development of BIA-based regional cell mass prediction formulas

Retrospective analysis of trends and production factors associated with sow mortality on swine-breeding farms in USA.

PubMed

Koketsu, Y

2000-09-01

Of the 825 pig farms in USA that mailed in their electronic file containing production records, 604 farms were used to observe breeding-female mortality risk and related factors (herd size, lactation length, parity and season). Multiple regression was used to determine factors associated with annual mortality risk. Analyses of variance were used for comparisons of mortality risks among parity and season groups. Average annual mortality risks during the 1997 period was 5.68%. Average breeding-female inventories and average lactation length on USA farms were 733 and 18.3 days, respectively. Higher annual breeding-female mortality risk was associated with larger herd size, greater parity at farrowing and shorter lactation length (P<0.02). For example, as herd size increases by 500 females, mortality risk increases by 0.44%. Older parity was associated with higher mortality risks. Summer season was also associated with higher mortality risk. Using five-years' records on 270 farms, annual mortality risk in 1997 was higher than those of 1993 and 1994, while average breeding-female inventory increased and lactation length decreased. It is recommended that producers, especially in large herds, pay more attention to breeding females.

Tisseel utilized as hemostatic in spine surgery impacts time to drain removal and length of stay.

PubMed

Epstein, Nancy E

2014-01-01

Although fibrin sealants (FSs) and fibrin glues (FGs) are predominantly utilized to strengthen repairs of cerebrospinal fluid (CSF) fistulas (deliberate/traumatic) during spinal surgery, they are also increasingly utilized to achieve hemostasis. Here, we investigated whether adding Tisseel (Baxter International Inc., Westlake Village, CA, USA), utilized to address increased bleeding during multilevel lumbar laminectomies with non-instrumented fusions, would reduce or equalize the time to drain removal and length of stay (LOS) without contributing to infections or prolonging time to fusion. Prospectively, 39 patients underwent multilevel laminectomies and 1-2 level non-instrumented (in situ) fusions to address stenosis/olisthesis; 22 who demonstrated increased intraoperative bleeding received Tisseel, while 17 without such bleeding did not. The 22 receiving versus 17 not receiving Tisseel, with similar clinical parameters, underwent comparable average multilevel laminectomies (4.36 and 4.25) and 1-2 level fusions (1.4 vs. 1.29 levels). As anticipated, for those receiving Tisseel, the average intraoperative estimated blood loss (EBL), total postoperative blood loss, and total perioperative transfusion requirements [red blood cells (RBC), fresh frozen plasma (FFP), platelets] were higher. However, Tisseel had the added benefit of equalizing the time to postoperative drain removal [e.g. 3.41 days (with) vs. 3.38 days (without)] and LOS [e.g. 5.86 days (with) vs. 5.82 days (without)] without increasing the infection rates (e.g. one superficial infection per group) or average times to fusion (e.g. 5.9 vs. 5.5 months). Adding Tisseel for increased bleeding during multilevel laminectomies/in situ fusions contributed to hemostasis by equalizing the average times to drain removal/LOS compared to patients without increased bleeding and not requiring Tisseel.

Self-Assembled Nanorod Structures on Nanofibers for Textile Electrochemical Capacitor Electrodes with Intrinsic Tactile Sensing Capabilities.

PubMed

Shi, HaoTian H; Khalili, Nazanin; Morrison, Taylor; Naguib, Hani E

2018-05-21

A novel polyaniline nanorod (PAniNR) three-dimensional structure was successfully grown on flexible polyacrylonitrile (PAN) nanofiber substrate as the electrode material for electrochemical capacitors (ECs), constructed via self-stabilized dispersion polymerization process. The electrode offered desired mechanical properties such as flexibility and bendability, whereas it maintained optimal electrochemical characteristics. The electrode and the assembled EC cell also achieved intrinsic piezoresistive sensing properties, leading to real-time monitoring of excess mechanical pressure and bending during cell operations. The PAniNR@PAN electrodes show an average diameter of 173.6 nm, with the PAniNR growth of 50.7 nm in length. Compared to the electrodes made from pristine PAni, the gravimetric capacitance increased by 39.8% to 629.6 F/g with aqueous acidic electrolyte. The electrode and the assembled EC cell with gel electrolyte were responsive to tensile, compressive, and bending stresses with a sensitivity of 0.95 MPa -1 .

Glioma grading using cell nuclei morphologic features in digital pathology images

NASA Astrophysics Data System (ADS)

Reza, Syed M. S.; Iftekharuddin, Khan M.

2016-03-01

This work proposes a computationally efficient cell nuclei morphologic feature analysis technique to characterize the brain gliomas in tissue slide images. In this work, our contributions are two-fold: 1) obtain an optimized cell nuclei segmentation method based on the pros and cons of the existing techniques in literature, 2) extract representative features by k-mean clustering of nuclei morphologic features to include area, perimeter, eccentricity, and major axis length. This clustering based representative feature extraction avoids shortcomings of extensive tile [1] [2] and nuclear score [3] based methods for brain glioma grading in pathology images. Multilayer perceptron (MLP) is used to classify extracted features into two tumor types: glioblastoma multiforme (GBM) and low grade glioma (LGG). Quantitative scores such as precision, recall, and accuracy are obtained using 66 clinical patients' images from The Cancer Genome Atlas (TCGA) [4] dataset. On an average ~94% accuracy from 10 fold crossvalidation confirms the efficacy of the proposed method.

An ex vivo feasibility experimental study on targeted cell surgery by high intensity focused ultrasound

NASA Astrophysics Data System (ADS)

Wang, Zhi Biao; Wu, Junru; Fang, Liao Qiong; Wang, Hua; Li, Fa Qi; Tian, Yun Bo; Gong, Xiao Bo; Zhang, Hong; Zhang, Lian; Feng, Ruo

2012-10-01

High intensity focused ultrasound (HIFU) has become a new noninvasive surgical modality in medicine. A portion of tissue seated inside a patient's body may experience coagulative necrosis after a few seconds of insonification by high intensity focused ultrasound (US) generated by an extracorporeal focusing US transducer. The region of tissue affected by coagulative necrosis (CN) usually has an ellipsoidal shape when the thermal effect due to US absorption plays the dominant role. Its long and short axes are parallel and perpendicular to the US propagation direction respectively. It was shown by ex vivo experiments that the dimension of the short and long axes of the tissue which experiences CN can be as small as 50 μm and 250 μm respectively after one second exposure of US pulse (the spatial and pulse average acoustic power is on the order of tens of Watts and the local acoustic spatial and temporal pulse averaged intensity is on the order of 3 × 104 W/cm2) generated by a 1.6 MHz HIFU transducer of 12 cm diameter and 11 cm geometric focal length (f-number = 0.92). The numbers of cells which suffered CN were estimated to be on the order of 40. This result suggests that HIFU is able to interact with tens of cells at/near its focal zone while keeping the neighboring cells minimally affected, and thus the targeted cell surgery may be achievable.

Assessment of Telomere Length, Phenotype, and DNA Content

PubMed Central

Kelesidis, Theodoros; Schmid, Ingrid

2017-01-01

Telomere sequences at the end of chromosomes control somatic cell division; therefore, telomere length in a given cell population provides information about its replication potential. This unit describes a method for flow cytometric measurement of telomere length in subpopulations using fluorescence in situ hybridization of fluorescently-labeled probes (Flow-FISH) without prior cell separation. After cells are stained for surface immunofluorescence, antigen-antibody complexes are covalently cross-linked onto cell membranes before FISH with a telomere-specific probe. Cells with long telomeres are included as internal standards. Addition of a DNA dye permits exclusion of proliferating cells during data analysis. DNA ploidy measurements of cells of interest and internal standard are performed on separate aliquots in parallel to Flow-FISH. Telomere fluorescence of G0/1 cells of subpopulations and internal standards obtained from Flow-FISH are normalized for DNA ploidy, and telomere length in subsets of interest is expressed as a fraction of the internal standard telomere length. PMID:28055113

Assessment of Telomere Length, Phenotype, and DNA Content.

PubMed

Kelesidis, Theodoros; Schmid, Ingrid

2017-01-05

Telomere sequences at the end of chromosomes control somatic cell division; therefore, telomere length in a given cell population provides information about its replication potential. This unit describes a method for flow cytometric measurement of telomere length in subpopulations using fluorescence in situ hybridization of fluorescently-labeled probes (Flow-FISH) without prior cell separation. After cells are stained for surface immunofluorescence, antigen-antibody complexes are covalently cross-linked onto cell membranes before FISH with a telomere-specific probe. Cells with long telomeres are included as internal standards. Addition of a DNA dye permits exclusion of proliferating cells during data analysis. DNA ploidy measurements of cells of interest and internal standard are performed on separate aliquots in parallel to Flow-FISH. Telomere fluorescence of G 0/1 cells of subpopulations and internal standards obtained from Flow-FISH are normalized for DNA ploidy, and telomere length in subsets of interest is expressed as a fraction of the internal standard telomere length. © 2017 by John Wiley & Sons, Inc. Copyright © 2017 John Wiley & Sons, Inc.

Robotic inferior vena cava surgery.

PubMed

Davila, Victor J; Velazco, Cristine S; Stone, William M; Fowl, Richard J; Abdul-Muhsin, Haidar M; Castle, Erik P; Money, Samuel R

2017-03-01

Inferior vena cava (IVC) surgery is uncommon and has traditionally been performed through open surgical approaches. Renal cell carcinoma with IVC extension generally requires vena cavotomy and reconstruction. Open removal of malpositioned IVC filters (IVCF) is occasionally required after endovascular retrieval attempts have failed. As our experience with robotic surgery has advanced, we have applied this technology to surgery of the IVC. We reviewed our institution's experience with robotic surgical procedures involving the IVC to determine its safety and efficacy. All patients undergoing robotic surgery that included cavotomy and repair from 2011 to 2014 were retrospectively reviewed. Data were obtained detailing preoperative demographics, operative details, and postoperative morbidity and mortality. Ten patients (6 men) underwent robotic vena caval procedures at our institution. Seven patients underwent robotic nephrectomy with removal of IVC tumor thrombus and retroperitoneal lymph node dissection. Three patients underwent robotic explantation of an IVCF after multiple endovascular attempts at removal had failed. The patients with renal cell carcinoma were a mean age of was 65.4 years (range, 55-74 years). Six patients had right-sided malignancy. All patients had T3b lesions at time of diagnosis. Mean tumor length extension into the IVC was 5 cm (range, 1-8 cm). All patients underwent robotic radical nephrectomy, with caval tumor thrombus removal and retroperitoneal lymph node dissection. The average operative time for patients undergoing surgery for renal cell carcinoma was 273 minutes (range, 137-382 minutes). Average intraoperative blood loss was 428 mL (range, 150-1200 mL). The patients with IVCF removal were a mean age of 33 years (range, 24-41 years). Average time from IVCF placement until robotic removal was 35.5 months (range, 4.3-57.3 months). Before robotic IVCF removal, a minimum of two endovascular retrievals were attempted. Average operative time for patients undergoing IVCF removal was 163 minutes (range, 131-202 minutes). Intraoperative blood loss averaged 250 mL (range, 150-350 mL). All procedures were completed robotically. The mean length of stay for all patients was 3.5 days (range, 1-8 days). All patients resumed ambulation on postoperative day 1. Nine patients resumed a regular diet on postoperative day 2. One patient with a renal tumor sustained a colon injury during initial adhesiolysis, before robotic radical nephrectomy, which was recognized at the initial operation and repaired robotically. Robotic radical nephrectomy and caval tumor removal were then completed. No blood transfusions were required intraoperatively, but three patients required blood transfusions postoperatively. Although robotic IVC surgery is uncommon, our initial limited experience demonstrates it is safe and efficacious. Copyright © 2016 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.

Diffusion length variation in 0.5- and 3-MeV-proton-irradiated, heteroepitaxial indium phosphide solar cells

NASA Technical Reports Server (NTRS)

Jain, Raj K.; Weinberg, Irving; Flood, Dennis J.

1993-01-01

Indium phosphide (InP) solar cells are more radiation resistant than gallium arsenide (GaAs) and silicon (Si) solar cells, and their growth by heteroepitaxy offers additional advantages leading to the development of light weight, mechanically strong, and cost-effective cells. Changes in heteroepitaxial InP cell efficiency under 0.5- and 3-MeV proton irradiations have been explained by the variation in the minority-carrier diffusion length. The base diffusion length versus proton fluence was calculated by simulating the cell performance. The diffusion length damage coefficient, K(sub L), was also plotted as a function of proton fluence.

Highly Unstable Double-Diffusive Finger Convection in a Hele-Shaw Cell: Baseline Experimental Data for Evaluation of Numerical Models

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

PRINGLE,SCOTT E.; COOPER,CLAY A.; GLASS JR.,ROBERT J.

An experimental investigation was conducted to study double-diffusive finger convection in a Hele-Shaw cell by layering a sucrose solution over a more-dense sodium chloride (NaCl) solution. The solutal Rayleigh numbers were on the order of 60,000, based upon the height of the cell (25 cm), and the buoyancy ratio was 1.2. A full-field light transmission technique was used to measure a dye tracer dissolved in the NaCl solution. They analyze the concentration fields to yield the temporal evolution of length scales associated with the vertical and horizontal finger structure as well as the mass flux. These measures show a rapidmore » progression through two early stages to a mature stage and finally a rundown period where mass flux decays rapidly. The data are useful for the development and evaluation of numerical simulators designed to model diffusion and convection of multiple components in porous media. The results are useful for correct formulation at both the process scale (the scale of the experiment) and effective scale (where the lab-scale processes are averaged-up to produce averaged parameters). A fundamental understanding of the fine-scale dynamics of double-diffusive finger convection is necessary in order to successfully parameterize large-scale systems.« less

Room temperature structures and odd even behaviour of a homologous series of anhydrous lithium n-alkanoates

NASA Astrophysics Data System (ADS)

White, Nicole A. S.; Ellis, Henry A.

2008-10-01

The molecular structures of a homologous series of lithium n-alkanoates have been determined at room temperature using infrared spectroscopy, polarizing light microscopy and X-ray powder diffraction in conjunction with density and melting point measurements. For all the compounds investigated, asymmetric ionic metal-carboxylate coordination is proposed, with the molecules located within a triclinic crystal system with P1¯ space group. The molecules are nearly all of similar structure and are arranged within lamellar layers with four molecules per unit cell. The hydrocarbon chains, in nearly all trans conformation, are arranged tail-to-tail and tilted at an average angle of 55 ο to the planes containing lithium ions. The unit cell parameters such as sides: b and c increase linearly with increasing chain length whilst side a shows a linear decrease. Furthermore, the measured densities and melting points show odd-even behaviour, suggesting differences in molecular packing between odd and even chain length homologues. Geometric models are proposed to explain molecular orientation within a lamella and odd-even behaviour, involving the influence of terminal groups on the packing geometry of hydrocarbon chains within the lattice.

Energy-Absorbing Beam Member

NASA Technical Reports Server (NTRS)

Littell, Justin D. (Inventor)

2017-01-01

An energy-absorbing (EA) beam member and having a cell core structure is positioned in an aircraft fuselage proximate to the floor of the aircraft. The cell core structure has a length oriented along a width of the fuselage, a width oriented along a length of the fuselage, and a depth extending away from the floor. The cell core structure also includes cell walls that collectively define a repeating conusoidal pattern of alternating respective larger and smaller first and second radii along the length of the cell core structure. The cell walls slope away from a direction of flight of the aircraft at a calibrated lean angle. An EA beam member may include the cell core structure and first and second plates along the length of the cell core structure on opposite edges of the cell material.

The importance of chain length for the polyphosphate enhancement of acidic potassium permanganate chemiluminescence.

PubMed

Holland, Brendan J; Adcock, Jacqui L; Nesterenko, Pavel N; Peristyy, Anton; Stevenson, Paul G; Barnett, Neil W; Conlan, Xavier A; Francis, Paul S

2014-09-09

Sodium polyphosphate is commonly used to enhance chemiluminescence reactions with acidic potassium permanganate through a dual enhancement mechanism, but commercially available polyphosphates vary greatly in composition. We have examined the influence of polyphosphate composition and concentration on both the dual enhancement mechanism of chemiluminescence intensity and the stability of the reagent under analytically useful conditions. The average chain length (n) provides a convenient characterisation, but materials with similar values can exhibit markedly different distributions of phosphate oligomers. There is a minimum polyphosphate chain length (∼6) required for a large enhancement of the emission intensity, but no further advantage was obtained using polyphosphate materials with much longer average chain lengths. Providing there is a sufficient average chain length, the optimum concentration of polyphosphate is dependent on the analyte and in some cases, may be lower than the quantities previously used in routine detection. However, the concentration of polyphosphate should not be lowered in permanganate reagents that have been partially reduced to form high concentrations of the key manganese(III) co-reactant, as this intermediate needs to be stabilised to prevent formation of insoluble manganese(IV). Copyright © 2014 Elsevier B.V. All rights reserved.

An assessment on convective and radiative heat transfer modelling in tubular solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Sánchez, D.; Muñoz, A.; Sánchez, T.

Four models of convective and radiative heat transfer inside tubular solid oxide fuel cells are presented in this paper, all of them applicable to multidimensional simulations. The work is aimed at assessing if it is necessary to use a very detailed and complicated model to simulate heat transfer inside this kind of device and, for those cases when simple models can be used, the errors are estimated and compared to those of the more complex models. For the convective heat transfer, two models are presented. One of them accounts for the variation of film coefficient as a function of local temperature and composition. This model gives a local value for the heat transfer coefficients and establishes the thermal entry length. The second model employs an average value of the transfer coefficient, which is applied to the whole length of the duct being studied. It is concluded that, unless there is a need to calculate local temperatures, a simple model can be used to evaluate the global performance of the cell with satisfactory accuracy. For the radiation heat transfer, two models are presented again. One of them considers radial radiation exclusively and, thus, radiative exchange between adjacent cells is neglected. On the other hand, the second model accounts for radiation in all directions but increases substantially the complexity of the problem. For this case, it is concluded that deviations between both models are higher than for convection. Actually, using a simple model can lead to a not negligible underestimation of the temperature of the cell.

On the properties of a bundle of flexible actin filaments in an optical trap.

PubMed

Perilli, Alessia; Pierleoni, Carlo; Ciccotti, Giovanni; Ryckaert, Jean-Paul

2016-06-28

We establish the statistical mechanics framework for a bundle of Nf living and uncrosslinked actin filaments in a supercritical solution of free monomers pressing against a mobile wall. The filaments are anchored normally to a fixed planar surface at one of their ends and, because of their limited flexibility, they grow almost parallel to each other. Their growing ends hit a moving obstacle, depicted as a second planar wall, parallel to the previous one and subjected to a harmonic compressive force. The force constant is denoted as the trap strength while the distance between the two walls as the trap length to make contact with the experimental optical trap apparatus. For an ideal solution of reactive filaments and free monomers at fixed free monomer chemical potential μ1, we obtain the general expression for the grand potential from which we derive averages and distributions of relevant physical quantities, namely, the obstacle position, the bundle polymerization force, and the number of filaments in direct contact with the wall. The grafted living filaments are modeled as discrete Wormlike chains, with F-actin persistence length ℓp, subject to discrete contour length variations ±d (the monomer size) to model single monomer (de)polymerization steps. Rigid filaments (ℓp = ∞), either isolated or in bundles, all provide average values of the stalling force in agreement with Hill's predictions Fs (H)=NfkBTln(ρ1/ρ1c)/d, independent of the average trap length. Here ρ1 is the density of free monomers in the solution and ρ1c its critical value at which the filament does not grow nor shrink in the absence of external forces. Flexible filaments (ℓp < ∞) instead, for values of the trap strength suitable to prevent their lateral escape, provide an average bundle force and an average trap length slightly larger than the corresponding rigid cases (few percents). Still the stalling force remains nearly independent on the average trap length, but results from the product of two strongly L-dependent contributions: the fraction of touching filaments ∝〈L〉(O.T.) (2) and the single filament buckling force ∝〈L〉(O.T.) (-2).

Fragment Length of Circulating Tumor DNA

PubMed Central

Underhill, Hunter R.; Kitzman, Jacob O.; Hellwig, Sabine; Welker, Noah C.; Daza, Riza; Gligorich, Keith M.; Rostomily, Robert C.; Shendure, Jay

2016-01-01

Malignant tumors shed DNA into the circulation. The transient half-life of circulating tumor DNA (ctDNA) may afford the opportunity to diagnose, monitor recurrence, and evaluate response to therapy solely through a non-invasive blood draw. However, detecting ctDNA against the normally occurring background of cell-free DNA derived from healthy cells has proven challenging, particularly in non-metastatic solid tumors. In this study, distinct differences in fragment length size between ctDNAs and normal cell-free DNA are defined. Human ctDNA in rat plasma derived from human glioblastoma multiforme stem-like cells in the rat brain and human hepatocellular carcinoma in the rat flank were found to have a shorter principal fragment length than the background rat cell-free DNA (134–144 bp vs. 167 bp, respectively). Subsequently, a similar shift in the fragment length of ctDNA in humans with melanoma and lung cancer was identified compared to healthy controls. Comparison of fragment lengths from cell-free DNA between a melanoma patient and healthy controls found that the BRAF V600E mutant allele occurred more commonly at a shorter fragment length than the fragment length of the wild-type allele (132–145 bp vs. 165 bp, respectively). Moreover, size-selecting for shorter cell-free DNA fragment lengths substantially increased the EGFR T790M mutant allele frequency in human lung cancer. These findings provide compelling evidence that experimental or bioinformatic isolation of a specific subset of fragment lengths from cell-free DNA may improve detection of ctDNA. PMID:27428049

Predicting deep neck space abscess using computed tomography.

PubMed

Smith, Joseph L; Hsu, Jack M; Chang, Jakwei

2006-01-01

To investigate objective measures that could increase the positive predictive value of computed tomography (CT) in diagnosing deep neck space infections (DNSIs). A retrospective analysis of patients surgically treated at a tertiary care hospital for DNSIs for more than 2 years were reviewed. Patients who had had CT with contrast scanning suggestive of deep neck space abscess within 24 hours before surgery were included. The average Hounsfield units for each abscess were calculated. Based on the intraoperative finding of pus, the patients were divided into groups. Student t tests compared the average Hounsfield units, white blood cell count, and maximum temperature between the groups. Outcomes were measured by comparing overall length of hospital stay, length of postoperative stay, and complications. Of the 32 patients surgically drained, 24 (75%) had discreet collections of pus, whereas 12 (25%) did not. Hounsfield unit measurement was not reliable in distinguishing abscess from phlegmon. None of the other clinical variables studied to distinguish abscess from phlegmon were statistically different either. A statistical difference between the 2 groups was not identified. Although CT with contrast plays an important role in the diagnosis and management of DNSIs, the decision for surgical drainage of an abscess should be made clinically. A negative exploration rate of nearly 25% despite careful selection criteria should be expected.

Investigation and Taguchi Optimization of Microbial Fuel Cell Salt Bridge Dimensional Parameters

NASA Astrophysics Data System (ADS)

Sarma, Dhrupad; Barua, Parimal Bakul; Dey, Nabendu; Nath, Sumitro; Thakuria, Mrinmay; Mallick, Synthia

2018-01-01

One major problem of two chamber salt bridge microbial fuel cells (MFCs) is the high resistance offered by the salt bridge to anion flow. Many researchers who have studied and optimized various parameters related to salt bridge MFC, have not shed much light on the effect of salt bridge dimensional parameters on the MFC performance. Therefore, the main objective of this research is to investigate the effect of length and cross sectional area of salt bridge and the effect of solar radiation and atmospheric temperature on MFC current output. An experiment has been designed using Taguchi L9 orthogonal array, taking length and cross sectional area of salt bridge as factors having three levels. Nine MFCs were fabricated as per the nine trial conditions. Trials were conducted for 3 days and output current of each of the MFCs along with solar insolation and atmospheric temperature were recorded. Analysis of variance shows that salt bridge length has significant effect both on mean (with 53.90% contribution at 95% CL) and variance (with 56.46% contribution at 87% CL), whereas the effect of cross sectional area of the salt bridge and the interaction of these two factors is significant on mean only (with 95% CL). Optimum combination was found at 260 mm salt bridge length and 506.7 mm2 cross sectional area with 4.75 mA of mean output current. The temperature and solar insolation data when correlated with each of the MFCs average output current, revealed that both external factors have significant impact on MFC current output but the correlation coefficient varies from MFC to MFC depending on salt bridge dimensional parameters.

Model development and verification for mass transport to Escherichia coli cells in a turbulent flow

NASA Astrophysics Data System (ADS)

Hondzo, Miki; Al-Homoud, Amer

2007-08-01

Theoretical studies imply that fluid motion does not significantly increase the molecular diffusive mass flux toward and away from microscopic organisms. This study presents experimental and theoretical evidence that small-scale turbulence modulates enhanced mass transport to Escherichia coli cells in a turbulent flow. Using the technique of inner region and outer region expansions, a model for dissolved oxygen and glucose uptake by E. coli was developed. The mass transport to the E. coli was modeled by the Sherwood (Sh)-Péclet (Pe) number relationship with redefined characteristic length and velocity scales. The model Sh = (1 + Pe1/2 + Pe) agreed with the laboratory measurements well. The Péclet number that quantifies the role and function of small-scale turbulence on E. coli metabolism is defined by Pe = (?) where Ezz is the root mean square of fluid extension in the direction of local vorticity, ηK is the Kolmogorov length scale, Lc is the length scale of E. coli, and D is the molecular diffusion coefficient. An alternative formulation for the redefined Pe is given by Pe = (?) where ? = 0.5(ɛν)1/4 is the Kolmogorov velocity averaged over the Kolmogorov length scale, ɛ is dissipation of turbulent kinetic energy, and ν is the kinematic viscosity of fluid. The dissipation of turbulent kinetic energy was estimated directly from measured velocity gradients and was within the reported range in engineered and natural aquatic ecosytems. The specific growth of E. coli was up to 5 times larger in a turbulent flow in comparison to the still water controls. Dissolved oxygen and glucose uptake were enhanced with increased ɛ in the turbulent flow.

30 CFR 206.103 - How do I value oil that is not sold under an arm's-length contract?

Code of Federal Regulations, 2010 CFR

2010-07-01

... arm's-length contract? 206.103 Section 206.103 Mineral Resources MINERALS MANAGEMENT SERVICE... oil that is not sold under an arm's-length contract? This section explains how to value oil that you... average of the gross proceeds accruing to the seller under your or your affiliates' arm's-length contracts...

Impact of sequencing depth and read length on single cell RNA sequencing data of T cells.

PubMed

Rizzetto, Simone; Eltahla, Auda A; Lin, Peijie; Bull, Rowena; Lloyd, Andrew R; Ho, Joshua W K; Venturi, Vanessa; Luciani, Fabio

2017-10-06

Single cell RNA sequencing (scRNA-seq) provides great potential in measuring the gene expression profiles of heterogeneous cell populations. In immunology, scRNA-seq allowed the characterisation of transcript sequence diversity of functionally relevant T cell subsets, and the identification of the full length T cell receptor (TCRαβ), which defines the specificity against cognate antigens. Several factors, e.g. RNA library capture, cell quality, and sequencing output affect the quality of scRNA-seq data. We studied the effects of read length and sequencing depth on the quality of gene expression profiles, cell type identification, and TCRαβ reconstruction, utilising 1,305 single cells from 8 publically available scRNA-seq datasets, and simulation-based analyses. Gene expression was characterised by an increased number of unique genes identified with short read lengths (<50 bp), but these featured higher technical variability compared to profiles from longer reads. Successful TCRαβ reconstruction was achieved for 6 datasets (81% - 100%) with at least 0.25 millions (PE) reads of length >50 bp, while it failed for datasets with <30 bp reads. Sufficient read length and sequencing depth can control technical noise to enable accurate identification of TCRαβ and gene expression profiles from scRNA-seq data of T cells.

Further characterization of loss of heterozygosity enhanced by p53 abrogation in human lymphoblastoid TK6 cells: disappearance of endpoint hotspots.

PubMed

Yatagai, Fumio; Morimoto, Shigeko; Kato, Takesi; Honma, Masamitsu

2004-06-13

Loss of heterozygosity (LOH) is the predominant mechanism of spontaneous mutagenesis at the heterozygous thymindine kinase locus (tk) in TK6 cells. LOH events detected in spontaneous TK(-) mutants (110 clones from p53 wild-type cells TK6-20C and 117 clones from p53-abrogated cells TK6-E6) were analyzed using 13 microsatellite markers spanning the whole of chromosome 17. Our analysis indicated an approximately 60-fold higher frequency of terminal deletions in p53-abrogated cells TK6-E6 compared to p53 wild-type cells TK6-20C whereas frequencies of point mutations (non-LOH events), interstitial deletions, and crossing over events were found to increase only less than twofold by such p53 abrogation. We then made use of an additional 17 microsatellite markers which provided an average map-interval of 1.6Mb to map various LOH endpoints on the 45Mb portion of chromosome 17q corresponding to the maximum length of LOH tracts (i.e. from the distal marker D17S932 to the terminal end). There appeared to be four prominent peaks (I-IV) in the distribution of LOH endpoints/Mb of Tk6-20C cells that were not evident in p53-abrogated cells TK6-E6, where they appeared to be rather broadly distributed along the 15-20Mb length (D17S1807 to D17S1607) surrounding two of the peaks that we detected in TK6-20C cells (peaks II and III). We suggest that the chromosomal instability that is so evident in TK6-E6 cells may be due to DNA double-strand break repair occurring through non homologous end-joining rather than allelic recombination.

Scattering of electromagnetic wave by the layer with one-dimensional random inhomogeneities

NASA Astrophysics Data System (ADS)

Kogan, Lev; Zaboronkova, Tatiana; Grigoriev, Gennadii., IV.

A great deal of attention has been paid to the study of probability characteristics of electro-magnetic waves scattered by one-dimensional fluctuations of medium dielectric permittivity. However, the problem of a determination of a density of a probability and average intensity of the field inside the stochastically inhomogeneous medium with arbitrary extension of fluc-tuations has not been considered yet. It is the purpose of the present report to find and to analyze the indicated functions for the plane electromagnetic wave scattered by the layer with one-dimensional fluctuations of permittivity. We assumed that the length and the amplitude of individual fluctuations as well the interval between them are random quantities. All of indi-cated fluctuation parameters are supposed as independent random values possessing Gaussian distribution. We considered the stationary time cases both small-scale and large-scale rarefied inhomogeneities. Mathematically such problem can be reduced to the solution of integral Fred-holm equation of second kind for Hertz potential (U). Using the decomposition of the field into the series of multiply scattered waves we obtained the expression for a probability density of the field of the plane wave and determined the moments of the scattered field. We have shown that all odd moments of the centered field (U-¡U¿) are equal to zero and the even moments depend on the intensity. It was obtained that the probability density of the field possesses the Gaussian distribution. The average field is small compared with the standard fluctuation of scattered field for all considered cases of inhomogeneities. The value of average intensity of the field is an order of a standard of fluctuations of field intensity and drops with increases the inhomogeneities length in the case of small-scale inhomogeneities. The behavior of average intensity is more complicated in the case of large-scale medium inhomogeneities. The value of average intensity is the oscillating function versus the average fluctuations length if the standard of fluctuations of inhomogeneities length is greater then the wave length. When the standard of fluctuations of medium inhomogeneities extension is smaller then the wave length, the av-erage intensity value weakly depends from the average fluctuations extension. The obtained results may be used for analysis of the electromagnetic wave propagation into the media with the fluctuating parameters caused by such factors as leafs of trees, cumulus, internal gravity waves with a chaotic phase and etc. Acknowledgment: This work was supported by the Russian Foundation for Basic Research (projects 08-02-97026 and 09-05-00450).

Estimating Gestational Age With Sonography: Regression-Derived Formula Versus the Fetal Biometric Average.

PubMed

Cawyer, Chase R; Anderson, Sarah B; Szychowski, Jeff M; Neely, Cherry; Owen, John

2018-03-01

To compare the accuracy of a new regression-derived formula developed from the National Fetal Growth Studies data to the common alternative method that uses the average of the gestational ages (GAs) calculated for each fetal biometric measurement (biparietal diameter, head circumference, abdominal circumference, and femur length). This retrospective cross-sectional study identified nonanomalous singleton pregnancies that had a crown-rump length plus at least 1 additional sonographic examination with complete fetal biometric measurements. With the use of the crown-rump length to establish the referent estimated date of delivery, each method's (National Institute of Child Health and Human Development regression versus Hadlock average [Radiology 1984; 152:497-501]), error at every examination was computed. Error, defined as the difference between the crown-rump length-derived GA and each method's predicted GA (weeks), was compared in 3 GA intervals: 1 (14 weeks-20 weeks 6 days), 2 (21 weeks-28 weeks 6 days), and 3 (≥29 weeks). In addition, the proportion of each method's examinations that had errors outside prespecified (±) day ranges was computed by using odds ratios. A total of 16,904 sonograms were identified. The overall and prespecified GA range subset mean errors were significantly smaller for the regression compared to the average (P < .01), and the regression had significantly lower odds of observing examinations outside the specified range of error in GA intervals 2 (odds ratio, 1.15; 95% confidence interval, 1.01-1.31) and 3 (odds ratio, 1.24; 95% confidence interval, 1.17-1.32) than the average method. In a contemporary unselected population of women dated by a crown-rump length-derived GA, the National Institute of Child Health and Human Development regression formula produced fewer estimates outside a prespecified margin of error than the commonly used Hadlock average; the differences were most pronounced for GA estimates at 29 weeks and later. © 2017 by the American Institute of Ultrasound in Medicine.

In vivo measurement of the average refractive index of the human crystalline lens using optical coherence tomography.

PubMed

de Freitas, Carolina; Ruggeri, Marco; Manns, Fabrice; Ho, Arthur; Parel, Jean-Marie

2013-01-15

We present a method for measuring the average group refractive index of the human crystalline lens in vivo using an optical coherence tomography (OCT) system which, allows full-length biometry of the eye. A series of OCT images of the eye including the anterior segment and retina were recorded during accommodation. Optical lengths of the anterior chamber, lens, and vitreous were measured dynamically along the central axis on the OCT images. The group refractive index of the crystalline lens along the central axis was determined using linear regression analysis of the intraocular optical length measurements. Measurements were acquired on three subjects of age 21, 24, and 35 years. The average group refractive index for the three subjects was, respectively, n=1.41, 1.43, and 1.39 at 835 nm.

Assessment of red blood cell deformability in type 2 diabetes mellitus and diabetic retinopathy by dual optical tweezers stretching technique.

PubMed

Agrawal, Rupesh; Smart, Thomas; Nobre-Cardoso, João; Richards, Christopher; Bhatnagar, Rhythm; Tufail, Adnan; Shima, David; Jones, Phil H; Pavesio, Carlos

2016-03-15

A pilot cross sectional study was conducted to investigate the role of red blood cells (RBC) deformability in type 2 diabetes mellitus (T2DM) without and with diabetic retinopathy (DR) using a dual optical tweezers stretching technique. A dual optical tweezers was made by splitting and recombining a single Nd:YAG laser beam. RBCs were trapped directly (i.e., without microbead handles) in the dual optical tweezers where they were observed to adopt a "side-on" orientation. RBC initial and final lengths after stretching were measured by digital video microscopy, and a Deformability index (DI) calculated. Blood from 8 healthy controls, 5 T2DM and 7 DR patients with respective mean age of 52.4 yrs, 51.6 yrs and 52 yrs was analysed. Initial average length of RBCs for control group was 8.45 ± 0.25 μm, 8.68 ± 0.49 μm for DM RBCs and 8.82 ± 0.32 μm for DR RBCs (p < 0.001). The DI for control group was 0.0698 ± 0.0224, and that for DM RBCs was 0.0645 ± 0.03 and 0.0635 ± 0.028 (p < 0.001) for DR group. DI was inversely related to basal length of RBCs (p =  .02). DI of RBC from DM and DR patients was significantly lower in comparison with normal healthy controls. A dual optical tweezers method can hence be reliably used to assess RBC deformability.

Environmental enrichment reveals effects of genotype on hippocampal spine morphologies in the mouse model of Fragile X Syndrome.

PubMed

Lauterborn, Julie C; Jafari, Matiar; Babayan, Alex H; Gall, Christine M

2015-02-01

Fragile X Syndrome (FXS) and the Fmr1 knockout (KO) mouse model of this disorder exhibit abnormal dendritic spines in neocortex, but the degree of spine disturbances in hippocampus is not clear. The present studies tested if the mutation influences dendritic branching and spine measures for CA1 pyramidal cells in Fmr1 KO and wild-type (WT) mice provided standard or enriched environment (EE) housing. Automated measures from 3D reconstructions of green fluorescent protein (GFP)-labeled cells showed that spine head volumes were ∼ 40% lower in KOs when compared with WTs in both housing conditions. With standard housing, average spine length was greater in KOs versus WTs but there was no genotype difference in dendritic branching, numbers of spines, or spine length distribution. However, with EE rearing, significant effects of genotype emerged including greater dendritic branching in WTs, greater spine density in KOs, and greater numbers of short thin spines in KOs when compared with WTs. Thus, EE rearing revealed greater effects of the Fmr1 mutation on hippocampal pyramidal cell morphology than was evident with standard housing, suggesting that environmental enrichment allows for fuller appreciation of the impact of the mutation and better representation of abnormalities likely to be present in human FXS. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Scaling dependence of memory windows and different carrier charging behaviors in Si nanocrystal nonvolatile memory devices

NASA Astrophysics Data System (ADS)

Yu, Jie; Chen, Kun-ji; Ma, Zhong-yuan; Zhang, Xin-xin; Jiang, Xiao-fan; Wu, Yang-qing; Huang, Xin-fan; Oda, Shunri

2016-09-01

Based on the charge storage mode, it is important to investigate the scaling dependence of memory performance in silicon nanocrystal (Si-NC) nonvolatile memory (NVM) devices for its scaling down limit. In this work, we made eight kinds of test key cells with different gate widths and lengths by 0.13-μm node complementary metal oxide semiconductor (CMOS) technology. It is found that the memory windows of eight kinds of test key cells are almost the same of about 1.64 V @ ± 7 V/1 ms, which are independent of the gate area, but mainly determined by the average size (12 nm) and areal density (1.8 × 1011/cm2) of Si-NCs. The program/erase (P/E) speed characteristics are almost independent of gate widths and lengths. However, the erase speed is faster than the program speed of test key cells, which is due to the different charging behaviors between electrons and holes during the operation processes. Furthermore, the data retention characteristic is also independent of the gate area. Our findings are useful for further scaling down of Si-NC NVM devices to improve the performance and on-chip integration. Project supported by the State Key Development Program for Basic Research of China (Grant No. 2010CB934402) and the National Natural Science Foundation of China (Grant Nos. 11374153, 61571221, and 61071008).

Understanding and Improving the Elastic Compressive Modulus of Fibre Reinforced Soy-Based Polyurethane Foams

NASA Astrophysics Data System (ADS)

Hussain, Sadakat

Soy-based polyurethane foams (PUFs) were reinforced with fibres of different aspect ratios to improve the compressive modulus. Each of the three fibre types reinforced PUF differently. Shorter micro-crystalline cellulose fibres were found embedded inside the cell struts of PUF and reinforced them. The reinforcement was attributed to be stress transfer from the matrix to the fibre by comparing the experimental results to those predicted by micro-mechanical models for short fibre reinforced composites. The reinforced cell struts increased the overall compressive modulus of the foam. Longer glass fibres (470 microns, length) provided the best reinforcement. These fibres were found to be larger than the cell diameters. The micro-mechanical models could not predict the reinforcement provided by the longer glass fibres. The models predicted negligible reinforcement because the very low modulus PUF should not transfer load to the higher modulus fibres. However, using a finite element model, it was determined that the fibres were providing reinforcement through direct fibre interaction with each other. Intermediate length glass fibres (260 microns, length) were found to poorly reinforce the PUF and should be avoided. These fibres were too short to interact with each other and were on average too large to embed and reinforce cell struts. In order to produce natural fibre reinforced PUFs in the future, a novel device was invented. The purpose of the device is to deliver natural fibres at a constant mass flow rate. The device was found to consistently meter individual loose natural fibre tufts at a mass flow rate of 2 grams per second. However, the device is not robust and requires further development to deliver a fine stream of natural fibre that can mix and interact with the curing polymeric components of PUF. A design plan was proposed to address the remaining issues with the device.

Sensitivity of subject-specific models to Hill muscle-tendon model parameters in simulations of gait.

PubMed

Carbone, V; van der Krogt, M M; Koopman, H F J M; Verdonschot, N

2016-06-14

Subject-specific musculoskeletal (MS) models of the lower extremity are essential for applications such as predicting the effects of orthopedic surgery. We performed an extensive sensitivity analysis to assess the effects of potential errors in Hill muscle-tendon (MT) model parameters for each of the 56 MT parts contained in a state-of-the-art MS model. We used two metrics, namely a Local Sensitivity Index (LSI) and an Overall Sensitivity Index (OSI), to distinguish the effect of the perturbation on the predicted force produced by the perturbed MT parts and by all the remaining MT parts, respectively, during a simulated gait cycle. Results indicated that sensitivity of the model depended on the specific role of each MT part during gait, and not merely on its size and length. Tendon slack length was the most sensitive parameter, followed by maximal isometric muscle force and optimal muscle fiber length, while nominal pennation angle showed very low sensitivity. The highest sensitivity values were found for the MT parts that act as prime movers of gait (Soleus: average OSI=5.27%, Rectus Femoris: average OSI=4.47%, Gastrocnemius: average OSI=3.77%, Vastus Lateralis: average OSI=1.36%, Biceps Femoris Caput Longum: average OSI=1.06%) and hip stabilizers (Gluteus Medius: average OSI=3.10%, Obturator Internus: average OSI=1.96%, Gluteus Minimus: average OSI=1.40%, Piriformis: average OSI=0.98%), followed by the Peroneal muscles (average OSI=2.20%) and Tibialis Anterior (average OSI=1.78%) some of which were not included in previous sensitivity studies. Finally, the proposed priority list provides quantitative information to indicate which MT parts and which MT parameters should be estimated most accurately to create detailed and reliable subject-specific MS models. Copyright © 2016 Elsevier Ltd. All rights reserved.

The effect of CD34+ cell telomere length and hTERT expression on the outcome of autologous CD34+ cell transplantation in patients with chronic heart failure.

PubMed

Rozman, Jasmina-Ziva; Perme, Maja Pohar; Jez, Mojca; Malicev, Elvira; Krasna, Metka; Novakovic, Srdjan; Vrtovec, Bojan; Rozman, Primoz

2017-09-01

Age-related telomere attrition in stem/progenitor cells may diminish their functional capacity and thereby impair the outcome of cell-based therapies. The aim of the present study was to investigate the effect of CD34 + cell telomere length and hTERT expression on the clinical outcome of autologous CD34 + cell transplantation. We studied 43 patients with cardiomyopathy. Their peripheral blood CD34 + cells were mobilized with granulocyte colony-stimulating factor, enriched by immunoselection and delivered transendocardially. Relative telomere length and expression levels of hTERT were measured using a real-time PCR assay. Immunoselected CD34 + cells had longer telomere length compared to leukocytes in leukapheresis products (p=0.001). In multivariate analysis, CD34 + cell telomere length was not associated with the clinical outcome (b=3.306, p=0.540). While hTERT expression was undetectable in all leukapheresis products, 94.4% of the CD34 + enriched cell products expressed hTERT. Higher CD34 + hTERT expression was associated with a better clinical outcome on univariate analysis (b=87.911, p=0.047). Our findings demonstrate that CD34 + cell telomere length may not influence the clinical outcome in cardiomyopathy patients treated with autologous CD34 + cell transplantation. Larger studies are needed to validate the impact of the CD34 + hTERT expression on the clinical outcome of autologous CD34 + cell transplantation. Copyright © 2017 Elsevier B.V. All rights reserved.

Differences in the length of the carboxyl terminus mediate functional properties of neurokinin-1 receptor

PubMed Central

Lai, Jian-Ping; Lai, Saien; Tuluc, Florin; Tansky, Morris F.; Kilpatrick, Laurie E.; Leeman, Susan E.; Douglas, Steven D.

2008-01-01

The neurokinin-1 receptor (NK1R) has two naturally occurring forms that differ in the length of the carboxyl terminus: a full-length receptor consisting of 407 aa and a truncated receptor consisting of 311 aa. We examined whether there are differential signaling properties attributable to the carboxyl terminus of this receptor by using stably transfected human embryonic kidney (HEK293) cell lines that express either full-length or truncated NK1R. Substance P (SP) specifically triggered intracellular calcium increase in HEK293 cells expressing full-length NK1R but had no effect in the cells expressing the truncated NK1R. In addition, in cells expressing full-length NK1R, SP activated NF-κB and IL-8 mRNA expression, but in cells expressing the truncated NK1R, SP did not activate NF-κB, and it decreased IL-8 mRNA expression. In cells expressing full-length NK1R, SP stimulated phosphorylation of PKCδ but inhibited phosphorylation of PKCδ in cells expressing truncated NK1R. There are also differences in the timing of SP-induced ERK activation in cells expressing the two different forms of the receptor. Full-length NK1R activation of ERK was rapid (peak within 1–2 min), whereas truncated NK1R-mediated activation was slower (peak at 20–30 min). Thus, the carboxyl terminus of NK1R is the structural basis for differences in the functional properties of the full-length and truncated NK1R. These differences may provide important information toward the design of new NK1R receptor antagonists. PMID:18713853

On the Trend of the Annual Mean, Maximum, and Minimum Temperature and the Diurnal Temperature Range in the Armagh Observatory, Northern Ireland, Dataset, 1844 -2012

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2013-01-01

Examined are the annual averages, 10-year moving averages, decadal averages, and sunspot cycle (SC) length averages of the mean, maximum, and minimum surface air temperatures and the diurnal temperature range (DTR) for the Armagh Observatory, Northern Ireland, during the interval 1844-2012. Strong upward trends are apparent in the Armagh surface-air temperatures (ASAT), while a strong downward trend is apparent in the DTR, especially when the ASAT data are averaged by decade or over individual SC lengths. The long-term decrease in the decadaland SC-averaged annual DTR occurs because the annual minimum temperatures have risen more quickly than the annual maximum temperatures. Estimates are given for the Armagh annual mean, maximum, and minimum temperatures and the DTR for the current decade (2010-2019) and SC24.

Tree Diamter Effects on Cost and Productivity of Cut-to-Length Systems

Treesearch

Matthew A. Holtzscher; Bobby L. Lanford

1997-01-01

Currently, there is a lack of economic information concerning cut-to-length harvesting systems. This study examined and measured the different costs of operating cut-to-length logging equipment over a range of average stand diameters at breast height. Three different cut-to-length logging systems were examined in this study. Systems included: 1) felier-buncher/manual/...

30 CFR 1206.103 - How do I value oil that is not sold under an arm's-length contract?

Code of Federal Regulations, 2012 CFR

2012-07-01

... arm's-length contract? 1206.103 Section 1206.103 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE... oil that is not sold under an arm's-length contract? This section explains how to value oil that you...-weighted average of the gross proceeds accruing to the seller under your or your affiliates' arm's-length...

30 CFR 1206.103 - How do I value oil that is not sold under an arm's-length contract?

Code of Federal Regulations, 2013 CFR

2013-07-01

... arm's-length contract? 1206.103 Section 1206.103 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE... oil that is not sold under an arm's-length contract? This section explains how to value oil that you...-weighted average of the gross proceeds accruing to the seller under your or your affiliates' arm's-length...

30 CFR 1206.103 - How do I value oil that is not sold under an arm's-length contract?

Code of Federal Regulations, 2014 CFR

2014-07-01

... arm's-length contract? 1206.103 Section 1206.103 Mineral Resources OFFICE OF NATURAL RESOURCES REVENUE... oil that is not sold under an arm's-length contract? This section explains how to value oil that you...-weighted average of the gross proceeds accruing to the seller under your or your affiliates' arm's-length...

Toroidal surface complexes of bacteriophage {phi}12 are responsible for host-cell attachment

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

Leo-Macias, Alejandra; Katz, Garrett; Wei Hui

2011-06-05

Cryo-electron tomography and subtomogram averaging are utilized to determine that the bacteriophage {phi}12, a member of the Cystoviridae family, contains surface complexes that are toroidal in shape, are composed of six globular domains with six-fold symmetry, and have a discrete density connecting them to the virus membrane-envelope surface. The lack of this kind of spike in a reassortant of {phi}12 demonstrates that the gene for the hexameric spike is located in {phi}12's medium length genome segment, likely to the P3 open reading frames which are the proteins involved in viral-host cell attachment. Based on this and on protein mass estimatesmore » derived from the obtained averaged structure, it is suggested that each of the globular domains is most likely composed of a total of four copies of P3a and/or P3c proteins. Our findings may have implications in the study of the evolution of the cystovirus species in regard to their host specificity. - Research Highlights: > Subtomogram averaging reveals enhanced detail of a {phi}12 cystovirus surface protein complex. > The surface protein complex has a toroidal shape and six-fold symmetry. > It is encoded by the medium-size genome segment. > The proteins of the surface complex most likely are one copy of P3a and three copies of P3c.« less

Burst firing and modulation of functional connectivity in cat striate cortex.

PubMed

Snider, R K; Kabara, J F; Roig, B R; Bonds, A B

1998-08-01

We studied the influences of the temporal firing patterns of presynaptic cat visual cortical cells on spike generation by postsynaptic cells. Multiunit recordings were dissected into the activity of individual neurons within the recorded group. Cross-correlation analysis was then used to identify directly coupled neuron pairs. The 22 multiunit groups recorded typically showed activity from two to six neurons, each containing between 1 and 15 neuron pairs. From a total of 241 neuron pairs, 91 (38%) had a shifted cross-correlation peak, which indicated a possible direct connection. Only two multiunit groups contained no shifted peaks. Burst activity, defined by groups of two or more spikes with intervals of

Antenna Mechanism of Length Control of Actin Cables

PubMed Central

Mohapatra, Lishibanya; Goode, Bruce L.; Kondev, Jane

2015-01-01

Actin cables are linear cytoskeletal structures that serve as tracks for myosin-based intracellular transport of vesicles and organelles in both yeast and mammalian cells. In a yeast cell undergoing budding, cables are in constant dynamic turnover yet some cables grow from the bud neck toward the back of the mother cell until their length roughly equals the diameter of the mother cell. This raises the question: how is the length of these cables controlled? Here we describe a novel molecular mechanism for cable length control inspired by recent experimental observations in cells. This “antenna mechanism” involves three key proteins: formins, which polymerize actin, Smy1 proteins, which bind formins and inhibit actin polymerization, and myosin motors, which deliver Smy1 to formins, leading to a length-dependent actin polymerization rate. We compute the probability distribution of cable lengths as a function of several experimentally tuneable parameters such as the formin-binding affinity of Smy1 and the concentration of myosin motors delivering Smy1. These results provide testable predictions of the antenna mechanism of actin-cable length control. PMID:26107518

Antenna Mechanism of Length Control of Actin Cables.

PubMed

Mohapatra, Lishibanya; Goode, Bruce L; Kondev, Jane

2015-06-01

Actin cables are linear cytoskeletal structures that serve as tracks for myosin-based intracellular transport of vesicles and organelles in both yeast and mammalian cells. In a yeast cell undergoing budding, cables are in constant dynamic turnover yet some cables grow from the bud neck toward the back of the mother cell until their length roughly equals the diameter of the mother cell. This raises the question: how is the length of these cables controlled? Here we describe a novel molecular mechanism for cable length control inspired by recent experimental observations in cells. This "antenna mechanism" involves three key proteins: formins, which polymerize actin, Smy1 proteins, which bind formins and inhibit actin polymerization, and myosin motors, which deliver Smy1 to formins, leading to a length-dependent actin polymerization rate. We compute the probability distribution of cable lengths as a function of several experimentally tuneable parameters such as the formin-binding affinity of Smy1 and the concentration of myosin motors delivering Smy1. These results provide testable predictions of the antenna mechanism of actin-cable length control.

PCB153 reduces telomerase activity and telomere length in immortalized human skin keratinocytes (HaCaT) but not in human foreskin keratinocytes (NFK)

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

Senthilkumar, P.K.; Robertson, L.W.; Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA

Polychlorinated biphenyls (PCBs), ubiquitous environmental pollutants, are characterized by long term-persistence in the environment, bioaccumulation, and biomagnification in the food chain. Exposure to PCBs may cause various diseases, affecting many cellular processes. Deregulation of the telomerase and the telomere complex leads to several biological disorders. We investigated the hypothesis that PCB153 modulates telomerase activity, telomeres and reactive oxygen species resulting in the deregulation of cell growth. Exponentially growing immortal human skin keratinocytes (HaCaT) and normal human foreskin keratinocytes (NFK) were incubated with PCB153 for 48 and 24 days, respectively, and telomerase activity, telomere length, superoxide level, cell growth, and cellmore » cycle distribution were determined. In HaCaT cells exposure to PCB153 significantly reduced telomerase activity, telomere length, cell growth and increased intracellular superoxide levels from day 6 to day 48, suggesting that superoxide may be one of the factors regulating telomerase activity, telomere length and cell growth compared to untreated control cells. Results with NFK cells showed no shortening of telomere length but reduced cell growth and increased superoxide levels in PCB153-treated cells compared to untreated controls. As expected, basal levels of telomerase activity were almost undetectable, which made a quantitative comparison of treated and control groups impossible. The significant down regulation of telomerase activity and reduction of telomere length by PCB153 in HaCaT cells suggest that any cell type with significant telomerase activity, like stem cells, may be at risk of premature telomere shortening with potential adverse health effects for the affected organism. -- Highlights: ► Human immortal (HaCaT) and primary (NFK) keratinocytes were exposed to PCB153. ► PCB153 significantly reduced telomerase activity and telomere length in HaCaT. ► No effect on telomere length and telomerase activity was found in NFK. ► Increased intracellular superoxide levels and reduced cell growth was seen in both. ► PCB153 may damage telomerase expressing cells like stem cells.« less

Study on the photo-induced oxygen reordering in YBa2Cu3O6+x

NASA Astrophysics Data System (ADS)

Milić, M. M.; Lazarov, N. Dj.; Cucić, D. A.

2012-05-01

Effect of the long term illumination of the YBa2Cu3O6+x with visible light or ultraviolet irradiation on its superconducting properties was studied in the frame of a simple theoretical model, which assumes that photodoping triggers rearrangement of oxygen monomers in the chain layers thus causing the enhancement of the average chain length, lav. Since, according to the model of charge transfer mechanism, long CuO chains are better electronic hole donors than the short ones, increase of the average chain length induces additional holes transfer from chain layers to the superconducting CuO2 planes which in turn leads to the increase of the superconducting transition temperature Tc. By the use of the expression for the chain length probability distribution and numerically calculated values for the average chain length in the non-excited system, we were able to estimate the doping p (number of holes per one Cu atom in the superconducting CuO2 planes) and Tc enhancement due to photo-induced oxygen reordering. The theoretical results are compared with available experimental data.

Vagal Intramuscular Arrays: The Specialized Mechanoreceptor Arbors That Innervate the Smooth Muscle Layers of the Stomach Examined in the Rat

PubMed Central

Powley, Terry L.; Hudson, Cherie N.; McAdams, Jennifer L.; Baronowsky, Elizabeth A.; Phillips, Robert J.

2016-01-01

The fundamental roles that the stomach plays in ingestion and digestion notwithstanding, little morphological information is available on vagal intramuscular arrays (IMAs), the afferents that innervate gastric smooth muscle. To characterize IMAs better, rats were given injections of dextran biotin in the nodose ganglia, and, after tracer transport, stomach whole mounts were collected. Specimens were processed for avidin–biotin permanent labeling, and subsets of the whole mounts were immunohistochemically processed for c-Kit or stained with cuprolinic blue. IMAs (n = 184) were digitized for morphometry and mapping. Throughout the gastric muscle wall, IMAs possessed common phenotypic features. Each IMA was generated by a parent neurite arborizing extensively, forming an array of multiple (mean = 212) branches averaging 193 μm in length. These branches paralleled, and coursed in apposition with, bundles of muscle fibers and interstitial cells of Cajal. Individual arrays averaged 4.3 mm in length and innervated volumes of muscle sheet, presumptive receptive fields, averaging 0.1 mm3. Evaluated by region and by muscle sheet, IMAs displayed architectural adaptations to the different loci. A subset (32%) of circular muscle IMAs issued specialized polymorphic collaterals to myenteric ganglia, and a subset (41%) of antral longitudinal muscle IMAs formed specialized net endings associated with the serosal boundary. IMAs were concentrated in regional patterns that correlated with the unique biomechanical adaptations of the stomach, specifically proximal stomach reservoir functions and antral emptying operations. Overall, the structural adaptations and distributions of the IMAs were consonant with the hypothesized stretch receptor roles of the afferents. PMID:26355387

Simulation study of poled low-water ionomers with different architectures

NASA Astrophysics Data System (ADS)

Allahyarov, Elshad; Taylor, Philip L.; Löwen, Hartmut

2011-11-01

The role of the ionomer architecture in the formation of ordered structures in poled membranes is investigated by molecular dynamics computer simulations. It is shown that the length of the sidechain Ls controls both the areal density of cylindrical aggregates Nc and the diameter of these cylinders in the poled membrane. The backbone segment length Lb tunes the average diameter Ds of cylindrical clusters and the average number of sulfonates Ns in each cluster. A simple empirical formula is noted for the dependence of the number density of induced rod-like aggregates on the sidechain length Ls within the parameter range considered in this study.

Correlation Between Echinoidea Size and Threat Level

NASA Astrophysics Data System (ADS)

Bakshi, S.; Lee, A.; Heim, N.; Payne, J.

2017-12-01

Echinoidea (or sea urchins), are small, spiny, globular, animals that populate the seafloors of nearly the entire planet. Echinoidea have existed on Earth since the Ordovician period, and from their archaic origin there is much to be learned about the relationship between Echinoidea body size and how it affects the survivability of the individual. The goal of this project is to determine how Echinoidea dimensions such as body volume, area, and length compare across extinct and extant species by plotting Echinoidea data in R. We will use stratigraphic data as a source to find which species of sea urchin from our data is extinct. We will then create three sets of three histograms of the size data for each type of measurement. One set will include histograms for sea urchin length, area, and volume. The other set will include histograms for extinct sea urchin length, area, and volume. The last set will include histograms for extant sea urchin length, area, and volume. Our data showed that extant sea urchins had a larger size, and extinct sea urchins were smaller. Our length data showed that the average length of all sea urchins were 54.95791 mm, the average length of extinct sea urchins were 51.0337 mm, and the average length of extant sea urchins were 66.12774 mm. There is a generally increasing trend of size over time, except for a small outlier about 350 million years ago, where echinoderm extinction selected towards larger species and biovolume was abnormally high. Our data also showed that over the past 200 million years, echinoderm extinction selectivity drove slightly smaller sea urchins towards extinction, further supporting the idea that a larger size was and still is advantageous for echinoderms.

Scale Dependence of Statistics of Spatially Averaged Rain Rate Seen in TOGA COARE Comparison with Predictions from a Stochastic Model

NASA Technical Reports Server (NTRS)

Kundu, Prasun K.; Bell, T. L.; Lau, William K. M. (Technical Monitor)

2002-01-01

A characteristic feature of rainfall statistics is that they in general depend on the space and time scales over which rain data are averaged. As a part of an earlier effort to determine the sampling error of satellite rain averages, a space-time model of rainfall statistics was developed to describe the statistics of gridded rain observed in GATE. The model allows one to compute the second moment statistics of space- and time-averaged rain rate which can be fitted to satellite or rain gauge data to determine the four model parameters appearing in the precipitation spectrum - an overall strength parameter, a characteristic length separating the long and short wavelength regimes and a characteristic relaxation time for decay of the autocorrelation of the instantaneous local rain rate and a certain 'fractal' power law exponent. For area-averaged instantaneous rain rate, this exponent governs the power law dependence of these statistics on the averaging length scale $L$ predicted by the model in the limit of small $L$. In particular, the variance of rain rate averaged over an $L \\times L$ area exhibits a power law singularity as $L \\rightarrow 0$. In the present work the model is used to investigate how the statistics of area-averaged rain rate over the tropical Western Pacific measured with ship borne radar during TOGA COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmospheric Response Experiment) and gridded on a 2 km grid depends on the size of the spatial averaging scale. Good agreement is found between the data and predictions from the model over a wide range of averaging length scales.

Lossless quantum data compression with exponential penalization: an operational interpretation of the quantum Rényi entropy.

PubMed

Bellomo, Guido; Bosyk, Gustavo M; Holik, Federico; Zozor, Steeve

2017-11-07

Based on the problem of quantum data compression in a lossless way, we present here an operational interpretation for the family of quantum Rényi entropies. In order to do this, we appeal to a very general quantum encoding scheme that satisfies a quantum version of the Kraft-McMillan inequality. Then, in the standard situation, where one is intended to minimize the usual average length of the quantum codewords, we recover the known results, namely that the von Neumann entropy of the source bounds the average length of the optimal codes. Otherwise, we show that by invoking an exponential average length, related to an exponential penalization over large codewords, the quantum Rényi entropies arise as the natural quantities relating the optimal encoding schemes with the source description, playing an analogous role to that of von Neumann entropy.

How the growth and freeboard of continents may relate to geometric and kinematic parameters of mid-ocean spreading ridges

USGS Publications Warehouse

Howell, D.G.

1989-01-01

If the volume of continents has been growing since 4 Ga then the area of the ocean basins must have been shrinking. Therefore, by inferring a constant continental freeboard, in addition to constant continental crustal thicknesses and seawater volume, it is possible to calculate the necessary combinations of increased ridge lengths and spreading rates required to displace the seawater in the larger oceans of the past in order to maintain the constant freeboard. A reasonable choice from the various possibilities is that at 4 Ga ago, the ridge length and spreading rates were ca. 2.5 times greater than the averages of these parameters during the past 200 Ma. By 2.5 Ga ago the ridge length and spreading rate decreased to about 1.8 times the recent average and by 1 Ga ago these features became reduced to approximately 1.4 times recent averages. ?? 1989.

PIV measurements in the near wakes of hollow cylinders with holes

NASA Astrophysics Data System (ADS)

Firat, Erhan; Ozkan, Gokturk M.; Akilli, Huseyin

2017-05-01

The wake flows behind fixed, hollow, rigid circular cylinders with two rows of holes connecting the front and rear stagnation lines were investigated using particle image velocimetry (PIV) for various combinations of three hole diameters, d = 0.1 D, 0.15 D, and 0.20 D, six hole-to-hole distances, l = 2 d, 3 d, 4 d, 5 d, 6 d, and 7 d, and ten angles of incidence ( α), from 0° to 45° in steps of 5°, at a Reynolds number of Re = 6,900. Time-averaged velocity distributions, instantaneous and time-averaged vorticity patterns, time-averaged streamline topology, and hot spots of turbulent kinetic energy occurred through the interaction of shear layers from the models were presented to show how the wake flow was modified by the presence of the self-issuing jets with various momentums emanating from the downstream holes. In general, as hole diameter which is directly related to jet momentum increased, the values of time-averaged wake characteristics (length of time-averaged recirculation region, vortex formation length, length of shear layers, and gap between the shear layers) increased. Irrespective to d and l tested, the values of the vortex formation length of the models are greater than that of the cylinder without hole (reference model). That is, vortex formation process was shifted downstream by aid of jets. It was found that time-averaged wake characteristics were very sensitive to α. As α increased, the variation of these characteristics can be modeled by exponential decay functions. The effect of l on the three-dimensional vortex shedding patterns in the near wake of the models was also discussed.

Neuromuscular organization of avian flight muscle: architecture of single muscle fibres in muscle units of the pectoralis (pars thoracicus) of pigeon (Columba livia)

PubMed Central

Sokoloff, A. J.

1999-01-01

The M. pectoralis (pars thoracicus) of pigeons (Columba livia) is comprised of short muscle fibres that do not extend from muscle origin to insertion but overlap 'in-series'. Individual pectoralis motor units are limited in territory to a portion of muscle length and are comprised of either fast twitch, oxidative and glycolytic fibres (FOG) or fast twitch and glycolytic fibres (FG). FOG fibres make up 88 to 90% of the total muscle population and have a mean diameter one-half of that of the relatively large FG fibres. Here we report on the organization of individual fibres identified in six muscle units depleted of glycogen, three comprised of FOG fibres and three comprised of FG fibres. For each motor unit, fibre counts revealed unequal numbers of depleted fibres in different unit cross-sections. We traced individual fibres in one unit comprised of FOG fibres and a second comprised of FG fibres. Six fibres from a FOG unit (total length 15.45 mm) ranged from 10.11 to 11.82 mm in length and averaged (± s.d.) 10.74 ± 0.79 mm. All originated bluntly (en mass) from a fascicle near the proximal end of the muscle unit and all terminated intramuscularly. Five of these ended in a taper and one ended bluntly. Fibres coursed on average for 70% of the muscle unit length. Six fibres from a FG unit (total length 34.76 mm) ranged from 8.97 to 18.38 mm in length and averaged 15.32 ± 3.75 mm. All originated bluntly and terminated intramuscularly; one of these ended in a taper and five ended bluntly. Fibres coursed on average for 44% of the muscle unit length. Because fibres of individual muscle units do not extend the whole muscle unit territory, the effective cross-sectional area changes along the motor unit length. These non-uniformities in the distribution of fibres within a muscle unit emphasize that the functional interactions within and between motor units are complex.

Early-Life Telomere Dynamics Differ between the Sexes and Predict Growth in the Barn Swallow (Hirundo rustica)

PubMed Central

Parolini, Marco; Romano, Andrea; Khoriauli, Lela; Nergadze, Solomon G.; Caprioli, Manuela; Rubolini, Diego; Santagostino, Marco; Saino, Nicola; Giulotto, Elena

2015-01-01

Telomeres are conserved DNA-protein structures at the termini of eukaryotic chromosomes which contribute to maintenance of genome integrity, and their shortening leads to cell senescence, with negative consequences for organismal functions. Because telomere erosion is influenced by extrinsic and endogenous factors, telomere dynamics may provide a mechanistic basis for evolutionary and physiological trade-offs. Yet, knowledge of fundamental aspects of telomere biology under natural selection regimes, including sex- and context-dependent variation in early-life, and the covariation between telomere dynamics and growth, is scant. In this study of barn swallows (Hirundo rustica) we investigated the sex-dependent telomere erosion during nestling period, and the covariation between relative telomere length and body and plumage growth. Finally, we tested whether any covariation between growth traits and relative telomere length depends on the social environment, as influenced by sibling sex ratio. Relative telomere length declined on average over the period of nestling maximal growth rate (between 7 and 16 days of age) and differently covaried with initial relative telomere length in either sex. The frequency distribution of changes in relative telomere length was bimodal, with most nestlings decreasing and some increasing relative telomere length, but none of the offspring traits predicted the a posteriori identified group to which individual nestlings belonged. Tail and wing length increased with relative telomere length, but more steeply in males than females, and this relationship held both at the within- and among-broods levels. Moreover, the increase in plumage phenotypic values was steeper when the sex ratio of an individual’s siblings was female-biased. Our study provides evidence for telomere shortening during early life according to subtly different dynamics in either sex. Furthermore, it shows that the positive covariation between growth and relative telomere length depends on sex as well as social environment, in terms of sibling sex ratio. PMID:26565632

Map showing length of freeze-free season in the Salina quadrangle, Utah

USGS Publications Warehouse

Covington, Harry R.

1972-01-01

In general, long freeze-free periods occur at low elevations, and short freeze-free periods occur at high elevations. But some valley floors have shorter freeze-free seasons than the glancing foothills because air cooled at high elevations flows downward and is trapped in the valleys. This temperature pattern occurs in the western part of the quadrangle in Rabbit Valley, Grass Valley, and the Sevier River Valley near Salina.Because year-round weather stations are sparse in Utah, a special technique for estimating length of freeze-free season was developed by Dr. Gaylen L. Ashcroft, Assistant Professor of Climatology, Utah State University, and E. Arlo Richardson, State Climatologist, U.S. Weather Bureau, based on average annual temperature, average annual temperature range, average daily temperature range, and average july maximum temperature. This technique was used in preparation of the map showing “Length of 32°F freeze-free season for Utah,” figure 23 in Hydrologic Atlas of Utah (Utah State University and Utah Division of Water Resources, 1968), from which the data for this map were taken.

Evaluation of telomere length in human cardiac tissues using cardiac quantitative FISH.

PubMed

Sharifi-Sanjani, Maryam; Meeker, Alan K; Mourkioti, Foteini

2017-09-01

Telomere length has been correlated with various diseases, including cardiovascular disease and cancer. The use of currently available telomere-length measurement techniques is often restricted by the requirement of a large amount of cells (Southern-based techniques) or the lack of information on individual cells or telomeres (PCR-based methods). Although several methods have been used to measure telomere length in tissues as a whole, the assessment of cell-type-specific telomere length provides valuable information on individual cell types. The development of fluorescence in situ hybridization (FISH) technologies enables the quantification of telomeres in individual chromosomes, but the use of these methods is dependent on the availability of isolated cells, which prevents their use with fixed archival samples. Here we describe an optimized quantitative FISH (Q-FISH) protocol for measuring telomere length that bypasses the previous limitations by avoiding contributions from undesired cell types. We have used this protocol on small paraffin-embedded cardiac-tissue samples. This protocol describes step-by-step procedures for tissue preparation, permeabilization, cardiac-tissue pretreatment and hybridization with a Cy3-labeled telomeric repeat complementing (CCCTAA) 3 peptide nucleic acid (PNA) probe coupled with cardiac-specific antibody staining. We also describe how to quantify telomere length by means of the fluorescence intensity and area of each telomere within individual nuclei. This protocol provides comparative cell-type-specific telomere-length measurements in relatively small human cardiac samples and offers an attractive technique to test hypotheses implicating telomere length in various cardiac pathologies. The current protocol (from tissue collection to image procurement) takes ∼28 h along with three overnight incubations. We anticipate that the protocol could be easily adapted for use on different tissue types.

Communications: Blood chemistry of laboratory-reared Golden trout

USGS Publications Warehouse

Hunn, Joseph B.; Wiedmeyer, Ray H.; Greer, Ivan E.; Grady, Andrew W.

1992-01-01

Golden trout Oncorhynchus aguabonita obtained from a wild stock as fertilized eggs were reared in the laboratory for 21 months. The laboratory-reared golden trout in our study reached sexual maturity earlier and grew more rapidly than wild golden trout do (according to the scientific literature). Male fish averaged 35.6 cm in total length and 426 g in weight, and females averaged 36.2 cm and 487 g. All golden trout were sexually mature when used for hematological analysis. The hematological profile (hematocrit, red blood cells, white blood cells, and thrombocytes) of golden trout was similar to that reported elsewhere for other trout species. Male and female golden trout did not have significantly different thrombocyte counts; however, the immobilization treatment used on the fish (anesthesia versus a blow to the head) resulted in significant treatment differences in thrombocyte numbers and interaction effect of sex in treatment for hematocrits. Gravid female golden trout had significantly higher plasma protein and calcium levels than did males. The ionic compositions of plasma (sodium, potassium, calcium, magnesium, copper, zinc, iron, and chloride) and gallbladder bile (calcium and chloride) were similar to those reported for other salmonids.

Comparison of theory and experiment for NAPL dissolution in porous media

NASA Astrophysics Data System (ADS)

Bahar, T.; Golfier, F.; Oltéan, C.; Lefevre, E.; Lorgeoux, C.

2018-04-01

Contamination of groundwater resources by an immiscible organic phase commonly called NAPL (Non Aqueous Phase Liquid) represents a major scientific challenge considering the residence time of such a pollutant. This contamination leads to the formation of NAPL blobs trapped in the soil and impact of this residual saturation cannot be ignored for correct predictions of the contaminant fate. In this paper, we present results of micromodel experiments on the dissolution of pure hydrocarbon phase (toluene). They were conducted for two values of the Péclet number. These experiments provide data for comparison and validation of a two-phase non-equilibrium theoretical model developed by Quintard and Whitaker (1994) using the volume averaging method. The model was directly upscaled from the averaged pore-scale mass balance equations. The effective properties of the macroscopic model were calculated over periodic unit cells designed from images of the experimental flow cell. Comparison of experimental and numerical results shows that the transport model predicts correctly - with no fitting parameters - the main mechanisms of NAPL mass transfer. The study highlights the crucial need of having a fair recovery of pore-scale characteristic lengths to predict the mass transfer coefficient with accuracy.

HIV enteropathy: HAART reduces HIV-induced stem cell hyperproliferation and crypt hypertrophy to normal in jejunal mucosa.

PubMed

Batman, Philip A; Kapembwa, Moses S; Belmonte, Liliana; Tudor, Gregory; Kotler, Donald P; Potten, Christopher S; Booth, Catherine; Cahn, Pedro; Griffin, George E

2014-01-01

To analyse the structural and kinetic response of small intestinal crypt epithelial cells including stem cells to highly active antiretroviral therapy (HAART). Crypt size and proliferative activity of transit and stem cells in jejunal mucosa were quantified using morphometric techniques. Crypt length was measured by counting the number of enterocytes along one side of a number of crypts in each biopsy specimen and the mean crypt length was calculated. Proliferating crypt cells were identified with MIB-1 monoclonal antibody, and the percentage of crypt cells in proliferation was calculated at each cell position along the length of the crypt (proliferation index). Data were obtained from 9 HIV-positive test patients co-infected with microsporidia, 34 HIV-positive patients receiving HAART and 13 control cases. Crypt length was significantly greater in test patients than in controls, but crypt length in patients receiving HAART was normal. The proliferation index was greater in test subjects than in controls in stem and transit cell compartments, and was decreased in patients treated with HAART only in the stem cell region of the crypt. Villous atrophy in HIV enteropathy is attributed to crypt hypertrophy and encroachment of crypt cells onto villi. HAART restores normal crypt structure by inhibition of HIV-driven stem cell hyperproliferation at the crypt bases.

On the properties of a bundle of flexible actin filaments in an optical trap

NASA Astrophysics Data System (ADS)

Perilli, Alessia; Pierleoni, Carlo; Ciccotti, Giovanni; Ryckaert, Jean-Paul

2016-06-01

We establish the statistical mechanics framework for a bundle of Nf living and uncrosslinked actin filaments in a supercritical solution of free monomers pressing against a mobile wall. The filaments are anchored normally to a fixed planar surface at one of their ends and, because of their limited flexibility, they grow almost parallel to each other. Their growing ends hit a moving obstacle, depicted as a second planar wall, parallel to the previous one and subjected to a harmonic compressive force. The force constant is denoted as the trap strength while the distance between the two walls as the trap length to make contact with the experimental optical trap apparatus. For an ideal solution of reactive filaments and free monomers at fixed free monomer chemical potential μ1, we obtain the general expression for the grand potential from which we derive averages and distributions of relevant physical quantities, namely, the obstacle position, the bundle polymerization force, and the number of filaments in direct contact with the wall. The grafted living filaments are modeled as discrete Wormlike chains, with F-actin persistence length ℓp, subject to discrete contour length variations ±d (the monomer size) to model single monomer (de)polymerization steps. Rigid filaments (ℓp = ∞), either isolated or in bundles, all provide average values of the stalling force in agreement with Hill's predictions Fs H = N f k B T ln ( ρ 1 / ρ 1 c) / d , independent of the average trap length. Here ρ1 is the density of free monomers in the solution and ρ1c its critical value at which the filament does not grow nor shrink in the absence of external forces. Flexible filaments (ℓp < ∞) instead, for values of the trap strength suitable to prevent their lateral escape, provide an average bundle force and an average trap length slightly larger than the corresponding rigid cases (few percents). Still the stalling force remains nearly independent on the average trap length, but results from the product of two strongly L-dependent contributions: the fraction of touching filaments ∝ (" separators=" < L >O . T .) 2 and the single filament buckling force ∝ (" separators=" < L >O . T .) - 2 .

NADH oxidase activity (NOX) and enlargement of HeLa cells oscillate with two different temperature-compensated period lengths of 22 and 24 minutes corresponding to different NOX forms

NASA Technical Reports Server (NTRS)

Wang, S.; Pogue, R.; Morre, D. M.; Morre, D. J.

2001-01-01

NOX proteins are cell surface-associated and growth-related hydroquinone (NADH) oxidases with protein disulfide-thiol interchange activity. A defining characteristic of NOX proteins is that the two enzymatic activities alternate to generate a regular period length of about 24 min. HeLa cells exhibit at least two forms of NOX. One is tumor-associated (tNOX) and is inhibited by putative quinone site inhibitors (e.g., capsaicin or the antitumor sulfonylurea, LY181984). Another is constitutive (CNOX) and refractory to inhibition. The periodic alternation of activities and drug sensitivity of the NADH oxidase activity observed with intact HeLa cells was retained in isolated plasma membranes and with the solubilized and partially purified enzyme. At least two activities were present. One had a period length of 24 min and the other had a period length of 22 min. The lengths of both the 22 and the 24 min periods were temperature compensated (approximately the same when measured at 17, 27 or 37 degrees C) whereas the rate of NADH oxidation approximately doubled with each 10 degrees C rise in temperature. The rate of increase in cell area of HeLa cells when measured by video-enhanced light microscopy also exhibited a complex period of oscillations reflective of both 22 and 24 min period lengths. The findings demonstrate the presence of a novel oscillating NOX activity at the surface of cancer cells with a period length of 22 min in addition to the constitutive NOX of non-cancer cells and tissues with a period length of 24 min.

Prostate Cancer Cell Telomere Length Variability and Stromal Cell Telomere Length as Prognostic Markers for Metastasis and Death

PubMed Central

Heaphy, Christopher M.; Yoon, Ghil Suk; Peskoe, Sarah B.; Joshu, Corinne E.; Lee, Thomas K.; Giovannucci, Edward; Mucci, Lorelei A.; Kenfield, Stacey A.; Stampfer, Meir J.; Hicks, Jessica L.; De Marzo, Angelo M.; Platz, Elizabeth A.; Meeker, Alan K.

2013-01-01

Current prognostic indicators are imperfect predictors of outcome in men with clinicallylocalized prostate cancer. Thus, tissue-based markers are urgently needed to improve treatment and surveillance decision-making. Given that shortened telomeres enhance chromosomal instability and such instability is a hallmark of metastatic lesions, we hypothesized that alterations in telomere length in the primary cancer would predict risk of progression to metastasis and prostate cancer death. To test this hypothesis, we conducted a prospective cohort study of 596 surgically treated men who participated in the ongoing Health Professionals Follow-up Study. Men who had the combination of more variable telomere length among prostate cancer cells (cell-to-cell) and shorter telomere length in prostate cancer-associated stromal cells were substantially more likely to progress to metastasis or die of their prostate cancer. These findings point to the translational potential of this telomere biomarker for prognostication and risk stratification for individualized therapeutic and surveillance strategies. PMID:23779129

Dependences of the geometrical parameters of cell community on stimulation voltage and frequency in chick embryonic cardiomyocytes

NASA Astrophysics Data System (ADS)

Fujii, Koki; Nomura, Fumimasa; Kaneko, Tomoyuki

2018-03-01

To investigate the optimal conditions for electrical stimulation, communities of lined-up chick embryonic cardiomyocytes were evaluated in terms of their threshold voltage for pacing (PVMin) and the half-maximum paced frequency (PF50), with a focus on the following factors: (1) the orientation of the major axis of cell communities to the electric field (EF) direction as the external factor; (2) the number of cells in a cell community, the length of the cell community, and the mean length of cells comprising the community as the internal factors. Firstly, PVMin decreased with increasing length of the cell network oriented parallel to the EF. PVMin was approximately 0.041 ± 0.025 V/mm when the community was sufficiently long. On the other hand, PVMin in the orthogonal orientation was constant at 1.7 ± 0.047 V/mm with no dependence on the length of the cell network. Secondly, we found that PF50 increased with increasing length of the cell network or the number of cells in the network; the PF50 values were 2.03 ± 0.05 and 3.39 ± 0.05 Hz when the respective cell network lengths were 100 µm (n = 43) and more than 300 µm (n = 6) and the cells were oriented parallel to the EF. These findings indicate that it is important to suppress ventricular fibrillation with minimal efficient stimulation by considering the EF direction with respect to the orientation of cardiomyocytes. Furthermore, expanded cells showed the loss of ability to respond to stimulation at higher frequencies. Cardiomyocytes combined with seeded fibroblasts as a cell network at a low density are a possible model of a ventricular remodeling heart.

North Atlantic Basin Tropical Cyclone Activity in Relation to Temperature and Decadal- Length Oscillation Patterns

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2009-01-01

Yearly frequencies of North Atlantic basin tropical cyclones, their locations of origin, peak wind speeds, average peak wind speeds, lowest pressures, and average lowest pressures for the interval 1950-2008 are examined. The effects of El Nino and La Nina on the tropical cyclone parametric values are investigated. Yearly and 10-year moving average (10-yma) values of tropical cyclone parameters are compared against those of temperature and decadal-length oscillation, employing both linear and bi-variate analysis, and first differences in the 10-yma are determined. Discussion of the 2009 North Atlantic basin hurricane season, updating earlier results, is given.

On the error probability of general tree and trellis codes with applications to sequential decoding

NASA Technical Reports Server (NTRS)

Johannesson, R.

1973-01-01

An upper bound on the average error probability for maximum-likelihood decoding of the ensemble of random binary tree codes is derived and shown to be independent of the length of the tree. An upper bound on the average error probability for maximum-likelihood decoding of the ensemble of random L-branch binary trellis codes of rate R = 1/n is derived which separates the effects of the tail length T and the memory length M of the code. It is shown that the bound is independent of the length L of the information sequence. This implication is investigated by computer simulations of sequential decoding utilizing the stack algorithm. These simulations confirm the implication and further suggest an empirical formula for the true undetected decoding error probability with sequential decoding.

[Comparative experiments of stripping sheep maxillary sinus mucosal with new-type stripper and umbrella detacher].

PubMed

Jiadong, Fan; Yanfeng, Li; Le, Liu; Yishi, Han; Pin, Hu; Yue, Zhang; Wenya, Bao

2016-10-01

To compare the stripping length obtained through the model of 0.012 and 0.014 of the nickel-titanium dual-stage maxillary sinus mucosa stripper, and the umbrella detacher. Twenty-four goats (1.5-2 years old) were chosen, randomly divided into A, B, C groups, each group of eight. Group A was 0.012 model group, group B was 0.014 model group, group C was umbrella detacher group. Animal model was established, and maxillary sinus mucosa was stripped to the left and right sides of the bottom of the sinus in three groups. The data was measured when stripping to the limit or being perforated. The average length of group A was 12.41 mm±4.35 mm, two cases perforated. The average length of group B was 23.38 mm±4.84 mm, one case perforated. The average length of group C was 2.61 mm±0.30 mm. The population mean of stripping length in three groups was not all the same calculated by analysis of variance (P<0.01). There were significant differences in the stripping length of the three groups by the SNK test (P<0.05). The nickel-titanium dual-stage maxillary sinus mucosa stripper can achieve a larger mucosal stripping range. The stripper with a model of 0.014 has a moderate flexibility and safety, and it can strip a large area of sinus mucosa.
.

Convergent and Divergent Validity of the Grammaticality and Utterance Length Instrument

ERIC Educational Resources Information Center

Castilla-Earls, Anny; Fulcher-Rood, Katrina

2018-01-01

Purpose: This feasibility study examines the convergent and divergent validity of the Grammaticality and Utterance Length Instrument (GLi), a tool designed to assess the grammaticality and average utterance length of a child's prerecorded story retell. Method: Three raters used the GLi to rate audio-recorded story retells from 100 English-speaking…

The topographic distribution of annual incoming solar radiation in the Rio Grande River basin

NASA Technical Reports Server (NTRS)

Dubayah, R.; Van Katwijk, V.

1992-01-01

We model the annual incoming solar radiation topoclimatology for the Rio Grande River basin in Colorado, U.S.A. Hourly pyranometer measurements are combined with satellite reflectance data and 30-m digital elevation models within a topographic solar radiation algorithm. Our results show that there is large spatial variability within the basin, even at an annual integration length, but the annual, basin-wide mean is close to that measured by the pyranometers. The variance within 16 sq km and 100 sq km regions is a linear function of the average slope in the region, suggesting a possible parameterization for sub-grid-cell variability.

Robustness of the p53 network and biological hackers.

PubMed

Dartnell, Lewis; Simeonidis, Evangelos; Hubank, Michael; Tsoka, Sophia; Bogle, I David L; Papageorgiou, Lazaros G

2005-06-06

The p53 protein interaction network is crucial in regulating the metazoan cell cycle and apoptosis. Here, the robustness of the p53 network is studied by analyzing its degeneration under two modes of attack. Linear Programming is used to calculate average path lengths among proteins and the network diameter as measures of functionality. The p53 network is found to be robust to random loss of nodes, but vulnerable to a targeted attack against its hubs, as a result of its architecture. The significance of the results is considered with respect to mutational knockouts of proteins and the directed attacks mounted by tumour inducing viruses.

Factors affecting pregnancy length and phases of parturition in Martina Franca jennies.

PubMed

Carluccio, Augusto; Gloria, Alessia; Veronesi, Maria Cristina; De Amicis, Ippolito; Noto, Federico; Contri, Alberto

2015-09-01

The knowledge of normal pregnancy length, duration of parturition stages, and neonatal early adaptation is mandatory for a rationale management of birth, especially in monotocous species with long gestations. This study reports data obtained from a large number of Martina Franca jennies with normal healthy pregnancies and spontaneous eutocic delivery of a mature, healthy, and viable donkey foal. Pregnancy lasts, on average, 371 days, and only the fetal gender significantly determines pregnancy length, with longer gestations observed in jennies bearing male fetuses. Other factors such as the year of foaling, month of ovulation, month of parturition, birth weight of the foal, and age of the jenny did not influence pregnancy length. The first stage of foaling lasted on average 65 minutes, the second stage 19 minutes, and the third stage 58 minutes. The umbilical cord ruptured on average within 16 minutes after birth; the foal stood up in 61 minutes and suckled the colostrum for the first time within 10 minutes after birth and again after 143 minutes of birth; meconium passage occurred, on average, 86 minutes after birth. Although times reported for the process of foaling are similar to data reported for the horse, the times for early neonatal donkey foal adaptation are longer as compared to the horse foal. Copyright © 2015 Elsevier Inc. All rights reserved.

Characterization of circulating tumor cell aggregates identified in patients with epithelial tumors

NASA Astrophysics Data System (ADS)

Cho, Edward H.; Wendel, Marco; Luttgen, Madelyn; Yoshioka, Craig; Marrinucci, Dena; Lazar, Daniel; Schram, Ethan; Nieva, Jorge; Bazhenova, Lyudmila; Morgan, Alison; Ko, Andrew H.; Korn, W. Michael; Kolatkar, Anand; Bethel, Kelly; Kuhn, Peter

2012-02-01

Circulating tumor cells (CTCs) have been implicated as a population of cells that may seed metastasis and venous thromboembolism (VTE), two major causes of mortality in cancer patients. Thus far, existing CTC detection technologies have been unable to reproducibly detect CTC aggregates in order to address what contribution CTC aggregates may make to metastasis or VTE. We report here an enrichment-free immunofluorescence detection method that can reproducibly detect and enumerate homotypic CTC aggregates in patient samples. We identified CTC aggregates in 43% of 86 patient samples. The fraction of CTC aggregation was investigated in blood draws from 24 breast, 14 non-small cell lung, 18 pancreatic, 15 prostate stage IV cancer patients and 15 normal blood donors. Both single CTCs and CTC aggregates were measured to determine whether differences exist in the physical characteristics of these two populations. Cells contained in CTC aggregates had less area and length, on average, than single CTCs. Nuclear to cytoplasmic ratios between single CTCs and CTC aggregates were similar. This detection method may assist future studies in determining which population of cells is more physically likely to contribute to metastasis and VTE.

Flow of Red Blood Cells in Stenosed Microvessels.

PubMed

Vahidkhah, Koohyar; Balogh, Peter; Bagchi, Prosenjit

2016-06-20

A computational study is presented on the flow of deformable red blood cells in stenosed microvessels. It is observed that the Fahraeus-Lindqvist effect is significantly enhanced due to the presence of a stenosis. The apparent viscosity of blood is observed to increase by several folds when compared to non-stenosed vessels. An asymmetric distribution of the red blood cells, caused by geometric focusing in stenosed vessels, is observed to play a major role in the enhancement. The asymmetry in cell distribution also results in an asymmetry in average velocity and wall shear stress along the length of the stenosis. The discrete motion of the cells causes large time-dependent fluctuations in flow properties. The root-mean-square of flow rate fluctuations could be an order of magnitude higher than that in non-stenosed vessels. Several folds increase in Eulerian velocity fluctuation is also observed in the vicinity of the stenosis. Surprisingly, a transient flow reversal is observed upstream a stenosis but not downstream. The asymmetry and fluctuations in flow quantities and the flow reversal would not occur in absence of the cells. It is concluded that the flow physics and its physiological consequences are significantly different in micro- versus macrovascular stenosis.

Flow of Red Blood Cells in Stenosed Microvessels

NASA Astrophysics Data System (ADS)

Vahidkhah, Koohyar; Balogh, Peter; Bagchi, Prosenjit

2016-06-01

A computational study is presented on the flow of deformable red blood cells in stenosed microvessels. It is observed that the Fahraeus-Lindqvist effect is significantly enhanced due to the presence of a stenosis. The apparent viscosity of blood is observed to increase by several folds when compared to non-stenosed vessels. An asymmetric distribution of the red blood cells, caused by geometric focusing in stenosed vessels, is observed to play a major role in the enhancement. The asymmetry in cell distribution also results in an asymmetry in average velocity and wall shear stress along the length of the stenosis. The discrete motion of the cells causes large time-dependent fluctuations in flow properties. The root-mean-square of flow rate fluctuations could be an order of magnitude higher than that in non-stenosed vessels. Several folds increase in Eulerian velocity fluctuation is also observed in the vicinity of the stenosis. Surprisingly, a transient flow reversal is observed upstream a stenosis but not downstream. The asymmetry and fluctuations in flow quantities and the flow reversal would not occur in absence of the cells. It is concluded that the flow physics and its physiological consequences are significantly different in micro- versus macrovascular stenosis.

Moss-associated methylobacteria as phytosymbionts: an experimental study

NASA Astrophysics Data System (ADS)

Hornschuh, M.; Grotha, R.; Kutschera, U.

2006-10-01

Methylotrophic bacteria inhabit the surface of plant organs, but the interaction between these microbes and their host cells is largely unknown. Protonemata (gametophytes) of the moss Funaria hygrometrica were cultivated in vitro under axenic conditions and the growth of the protonemal filaments recorded. In the presence of methylobacteria (different strains of Methylobacterium), average cell length and the number of cells per filament were both enhanced. We tested the hypothesis that auxin (indole-3-acetic acid, IAA), secreted by the epiphytic bacteria and taken up by the plant cells, may in part be responsible for this promotion of protonema development. The antiauxin parachlorophenoxyisobutyric acid (PCIB) was used as a tool to analyze the role of IAA and methylobacteria in the regulation of cell growth. In the presence of PCIB, cell elongation and protonema differentiation were both inhibited. This effect was compensated for by the addition of different Methylobacterium strains to the culture medium. Biosynthesis and secretion of IAA by methylobacteria maintained in liquid culture was documented via a colorimetric assay and thin layer chromatography. Our results support the hypothesis that the development of Funaria protonemata is promoted by beneficial phytohormone-producing methylobacteria, which can be classified as phytosymbionts.

Moss-associated methylobacteria as phytosymbionts: an experimental study.

PubMed

Hornschuh, M; Grotha, R; Kutschera, U

2006-10-01

Methylotrophic bacteria inhabit the surface of plant organs, but the interaction between these microbes and their host cells is largely unknown. Protonemata (gametophytes) of the moss Funaria hygrometrica were cultivated in vitro under axenic conditions and the growth of the protonemal filaments recorded. In the presence of methylobacteria (different strains of Methylobacterium), average cell length and the number of cells per filament were both enhanced. We tested the hypothesis that auxin (indole-3-acetic acid, IAA), secreted by the epiphytic bacteria and taken up by the plant cells, may in part be responsible for this promotion of protonema development. The antiauxin parachlorophenoxyisobutyric acid (PCIB) was used as a tool to analyze the role of IAA and methylobacteria in the regulation of cell growth. In the presence of PCIB, cell elongation and protonema differentiation were both inhibited. This effect was compensated for by the addition of different Methylobacterium strains to the culture medium. Biosynthesis and secretion of IAA by methylobacteria maintained in liquid culture was documented via a colorimetric assay and thin layer chromatography. Our results support the hypothesis that the development of Funaria protonemata is promoted by beneficial phytohormone-producing methylobacteria, which can be classified as phytosymbionts.

The random coding bound is tight for the average code.

NASA Technical Reports Server (NTRS)

Gallager, R. G.

1973-01-01

The random coding bound of information theory provides a well-known upper bound to the probability of decoding error for the best code of a given rate and block length. The bound is constructed by upperbounding the average error probability over an ensemble of codes. The bound is known to give the correct exponential dependence of error probability on block length for transmission rates above the critical rate, but it gives an incorrect exponential dependence at rates below a second lower critical rate. Here we derive an asymptotic expression for the average error probability over the ensemble of codes used in the random coding bound. The result shows that the weakness of the random coding bound at rates below the second critical rate is due not to upperbounding the ensemble average, but rather to the fact that the best codes are much better than the average at low rates.

Acetylcholine, carbachol, and GABA induce no detectable change in the length of isolated outer hair cells.

PubMed

Bobbin, R P; Fallon, M; Puel, J L; Bryant, G; Bledsoe, S C; Zajic, G; Schacht, J

1990-08-01

The mechanical and electrical properties of cochlear outer hair cells (OHCs) are suggested to modulate transduction by inner hair cells. These properties of OHCs are presumably regulated by efferent neurons which use several transmitters including acetylcholine (Ach) and gamma aminobutyric acid (GABA). Since it had been suggested that Ach causes isolated OHCs to shorten visibly, this study was designed to investigate whether GABA also alters the length of OHCs. OHCs were isolated from the guinea pig cochlea by mechanical dispersion after collagenase treatment. Cells were initially selected by strict morphological criteria. In addition they were only included in further studies if they attained a constant length during 10 min of superfusion with buffer solution. Neither GABA (20 microM: 100 microM), Ach (5 mM; 10 microM with 10 microM eserine) or carbachol (10 microM; 100 microM) altered OHC length when applied in iso-osmotic Hank's balanced salt solution (total number of cells tested, 72). If a change in length occurred it must have been smaller than 0.3 microns, our detection ability. In contrast, high potassium and variations in osmolarity changed hair cell length by 3-10% in agreement with other reports.

Finite-Length Diocotron Modes in a Non-neutral Plasma Column

NASA Astrophysics Data System (ADS)

Walsh, Daniel; Dubin, Daniel

2017-10-01

Diocotron modes are 2D distortions of a non-neutral plasma column that propagate azimuthally via E × B drifts. While the infinite-length theory of diocotron modes is well-understood for arbitrary azimuthal mode number l, the finite-length mode frequency is less developed (with some exceptions), and is naturally of relevance to experiments. In this poster, we present an approach to address finite length effects, such as temperature dependence of the mode frequency. We use a bounce-averaged solution to the Vlasov Equation, in which the Vlasov Equation is solved using action-angle variables of the unperturbed Hamiltonian. We write the distribution function as a Fourier series in the bounce-angle variable ψ, keeping only the bounce-averaged term. We demonstrate a numerical solution to this equation for a realistic plasma with a finite Debye Length, compare to the existing l = 1 theory, and discuss possible extensions of the existing theory to l ≠ 1 . Supported by NSF/DOE Partnership Grants PHY1414570 and DESC0002451.

Accurate cell counts in live mouse embryos using optical quadrature and differential interference contrast microscopy

NASA Astrophysics Data System (ADS)

Warger, William C., II; Newmark, Judith A.; Zhao, Bing; Warner, Carol M.; DiMarzio, Charles A.

2006-02-01

Present imaging techniques used in in vitro fertilization (IVF) clinics are unable to produce accurate cell counts in developing embryos past the eight-cell stage. We have developed a method that has produced accurate cell counts in live mouse embryos ranging from 13-25 cells by combining Differential Interference Contrast (DIC) and Optical Quadrature Microscopy. Optical Quadrature Microscopy is an interferometric imaging modality that measures the amplitude and phase of the signal beam that travels through the embryo. The phase is transformed into an image of optical path length difference, which is used to determine the maximum optical path length deviation of a single cell. DIC microscopy gives distinct cell boundaries for cells within the focal plane when other cells do not lie in the path to the objective. Fitting an ellipse to the boundary of a single cell in the DIC image and combining it with the maximum optical path length deviation of a single cell creates an ellipsoidal model cell of optical path length deviation. Subtracting the model cell from the Optical Quadrature image will either show the optical path length deviation of the culture medium or reveal another cell underneath. Once all the boundaries are used in the DIC image, the subtracted Optical Quadrature image is analyzed to determine the cell boundaries of the remaining cells. The final cell count is produced when no more cells can be subtracted. We have produced exact cell counts on 5 samples, which have been validated by Epi-Fluorescence images of Hoechst stained nuclei.

Reconstructing the in vivo dynamics of hematopoietic stem cells from telomere length distributions

PubMed Central

Werner, Benjamin; Beier, Fabian; Hummel, Sebastian; Balabanov, Stefan; Lassay, Lisa; Orlikowsky, Thorsten; Dingli, David; Brümmendorf, Tim H; Traulsen, Arne

2015-01-01

We investigate the in vivo patterns of stem cell divisions in the human hematopoietic system throughout life. In particular, we analyze the shape of telomere length distributions underlying stem cell behavior within individuals. Our mathematical model shows that these distributions contain a fingerprint of the progressive telomere loss and the fraction of symmetric cell proliferations. Our predictions are tested against measured telomere length distributions in humans across all ages, collected from lymphocyte and granulocyte sorted telomere length data of 356 healthy individuals, including 47 cord blood and 28 bone marrow samples. We find an increasing stem cell pool during childhood and adolescence and an approximately maintained stem cell population in adults. Furthermore, our method is able to detect individual differences from a single tissue sample, i.e. a single snapshot. Prospectively, this allows us to compare cell proliferation between individuals and identify abnormal stem cell dynamics, which affects the risk of stem cell related diseases. DOI: http://dx.doi.org/10.7554/eLife.08687.001 PMID:26468615

Percutaneous epiphysiodesis using transphyseal screws (PETS): prospective case study and review.

PubMed

Nouth, Fred; Kuo, Leonard A

2004-01-01

Percutaneous epiphysiodesis using transphyseal screws (PETS) is a relatively new procedure being used for the correction of moderate leg length discrepancy and angular deformities in children. Over a mean follow-up of 2.4 years the authors followed prospectively 18 patients who underwent PETS. Nine had correction of angular deformity and nine had leg length inequality. The average reduction in leg length discrepancy was from 3.33 to 1.36 cm. The average improvement in angular deformity was 69%. This quick, minimally invasive, and potentially reversible procedure has the added benefits of a short hospital stay with low morbidity, making it a suitable alternative to the more traditional methods of epiphysiodesis.

Realizing the Translational Potential of Telomere Length Variation as a Tissue-Based Prognostic Marker for Prostate Cancer

DTIC Science & Technology

2014-10-01

Telomere Length Variation as a Tissue- Based Prognostic Marker for Prostate Cancer PRINCIPAL INVESTIGATOR: Elizabeth A. Platz CONTRACTING...Translational Potential of Telomere Length Variation as a Tissue- Based Prognostic Marker for Prostate Cancer 5b. GRANT NUMBER W81XWH-12-1-0545 5c...combination of telomere length variability in prostate cancer cells and short telomere length in cancer-associated stromal cells is an independent

Telomere shortening in hematopoietic stem cell transplantation: a potential mechanism for late graft failure?

PubMed

Awaya, Norihiro; Baerlocher, Gabriela M; Manley, Thomas J; Sanders, Jean E; Mielcarek, Marco; Torok-Storb, Beverly; Lansdorp, Peter M

2002-01-01

Telomeres serve to maintain the structural integrity of chromosomes, yet each somatic cell division is associated with a decrease in telomere length. The cumulative decrease in telomere length can impose an upper limit for the number of cell divisions that can occur before a cell senesces. When studied in vitro with fibroblasts, this limit is referred to as the Hayflick limit and usually occurs after 40 to 80 cell doublings. In theory, a similar replicative potential in a hematopoietic stem cell could support hematopoiesis in a person for more than 100 years. However, stem cells differentiate, and the telomere length differs among chromosomes within a single cell, among cell types, and among age-matched individuals. This variation in telomere length raises the possibility that long-term hematopoiesis by transplanted stem cells could, depending on the telomere length of the engrafted stem cell and the proliferative demand to which it is subjected, reach a Hayflick limit during the life span of the patient. Although significant shortening of telomeres is reported to occur within the first year posttransplantation, as yet no evidence has indicated that this shortening is associated with marrow function. In this review, we summarize reports on telomere shortening in stem cell transplantation recipients and report 2 cases in which graft failure is associated with significant telomere shortening.

Long-Term Effects of Radiation Exposure and Metabolic Status on Telomere Length of Peripheral Blood T Cells in Atomic Bomb Survivors.

PubMed

Yoshida, Kengo; Misumi, Munechika; Kubo, Yoshiko; Yamaoka, Mika; Kyoizumi, Seishi; Ohishi, Waka; Hayashi, Tomonori; Kusunoki, Yoichiro

2016-10-01

In a series of studies of atomic bomb survivors, radiation-dose-dependent alterations in peripheral T-cell populations have been reported. For example, reduced size in naïve T-cell pools and impaired proliferation ability of T cells were observed. Because these alterations are also generally observed with human aging, we hypothesized that radiation exposure may accelerate the aging process of the T-cell immune system. To further test this hypothesis, we conducted cross-sectional analyses of telomere length, a hallmark of cellular aging, of naïve and memory CD4 T cells and total CD8 T cells in the peripheral blood of 620 atomic bomb survivors as it relates to age and radiation dose, using fluorescence in situ hybridization with flow cytometry. Since telomere shortening has been recently demonstrated in obesity-related metabolic abnormalities and diseases, the modifying effects of metabolic status were also examined. Our results indicated nonlinear relationships between T-cell telomere length and prior radiation exposure, i.e., longer telomeres with lower dose exposure and a decreasing trend of telomere length with individuals exposed to doses higher than 0.5 Gy. There were associations between shorter T-cell telomeres and higher hemoglobin Alc levels or fatty liver development. In naïve and memory CD4 T cells, radiation dose and high-density lipoprotein (HDL) cholesterol were found to positively interact with telomere length, suggesting that the decreasing trend of telomere length from a higher radiation dose was less conspicuous in individuals with a higher HDL cholesterol. It is therefore likely that radiation exposure perturbs T-cell homeostasis involving telomere length maintenance by multiple biological mechanisms, depending on dose, and that long-term-radiation-induced effects on the maintenance of T-cell telomeres may be modified by the subsequent metabolic conditions of individuals.

Incubation behavior of Spectacled Eiders on the Yukon-Kuskokwim Delta, Alaska

USGS Publications Warehouse

Flint, Paul L.; Grand, J.B.

1999-01-01

We studied incubation behavior of Spectacled Eiders (Somateria fischeri) on the Yukon-Kuskokwim Delta in 1996. We trapped 19 females on their nests and weighed them in early incubation and again at hatch. Average daily weight loss for incubating females was 16.6 ?? 1.0 g day-1, which resulted in a cumulative loss of 26% of body weight throughout incubation. Nest attendance was monitored for a portion of the incubation period using temperature sensing artificial eggs. Incubation constancy averaged 90 ?? 1%. Average recess length was 37.1 ?? 0.9 min, and nests cooled an average of 4.2 ?? 0.1??C during recesses. Recess frequency averaged 2.5 ?? 0.1 recesses day-1, and most recesses (70%) occurred between 10:00 and 22: 00. Incubation constancy varied among females, but was not related to changes in body weight or incubation period. There was no influence of ambient temperature on incubation recess length, however most recesses were taken during the warmest part of the day. We found considerable variation among females in patterns of daily incubation constancy, nest cooling, recess frequency, and recess length. It is not clear from our results what factors constrain incubation behavior of Spectacled Eiders, but we suggest that individual females respond to a complex suite of variables.

Light Management in Flexible Glass by Wood Cellulose Coating

PubMed Central

Fang, Zhi-Qiang; Zhu, Hong-Li; Li, Yuan-Yuan; Liu, Zhen; Dai, Jia-Qi; Preston, Colin; Garner, Sean; Cimo, Pat; Chai, Xin-Sheng; Chen, Gang; Hu, Liang-Bing

2014-01-01

Ultra-thin flexible glass with high transparency is attractive for a broad range of display applications; however, substrates with low optical haze are not ideal for thin film solar cells, since most of the light will go through the semiconductor layer without scattering, and the length of light travelling path in the active layer is small. By simply depositing a layer of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-oxidized wood fibers (TOWFs), we are able to tailor the optical properties of flexible glass dramatically from exhibiting low haze (<1%) to high haze (~56%) without compromising the total forward transmittance (~90%). The influence of the TOWFs morphology on the optical properties of TOWFs-coated flexible glass is investigated. As the average fiber length decreases, the transmission haze of TOWF-coated flexible glass illustrates a decreasing trend. Earth-abundant natural materials for transparent, hazy, and flexible glass have tremendous applicability in the fabrication of flexible optoelectronics with tunable light scattering effects by enabling inexpensive and large-scale processes. PMID:25068486

The scaling features of the 3D organization of chromosomes are highlighted by a transformation à la Kadanoff of Hi-C data

NASA Astrophysics Data System (ADS)

Chiariello, Andrea M.; Bianco, Simona; Annunziatella, Carlo; Esposito, Andrea; Nicodemi, Mario

2017-11-01

Technologies such as Hi-C and GAM have revealed that chromosomes are not randomly folded into the nucleus of cells, but are composed by a sequence of contact domains (TADs), each typically 0.5 Mb long. However, the larger scale organization of the genome remains still not well understood. To investigate the scaling behaviour of chromosome folding, here we apply an approach à la Kadanoff, inspired by the Renormalization Group theory, to Hi-C interaction data, across different cell types and chromosomes. We find that the genome is characterized by complex scaling features, where the average size of contact domains exhibits a power-law behaviour with the rescaling level. That is compatible with the existence of contact domains extending across length scales up to chromosomal sizes. The scaling exponent is statistically indistinguishable among the different murine cell types analysed. These results point toward a scenario of a universal higher-order spatial architecture of the genome, which could reflect fundamental, organizational principles.

Deriving flow directions for coarse-resolution (1-4 km) gridded hydrologic modeling

NASA Astrophysics Data System (ADS)

Reed, Seann M.

2003-09-01

The National Weather Service Hydrology Laboratory (NWS-HL) is currently testing a grid-based distributed hydrologic model at a resolution (4 km) commensurate with operational, radar-based precipitation products. To implement distributed routing algorithms in this framework, a flow direction must be assigned to each model cell. A new algorithm, referred to as cell outlet tracing with an area threshold (COTAT) has been developed to automatically, accurately, and efficiently assign flow directions to any coarse-resolution grid cells using information from any higher-resolution digital elevation model. Although similar to previously published algorithms, this approach offers some advantages. Use of an area threshold allows more control over the tendency for producing diagonal flow directions. Analyses of results at different output resolutions ranging from 300 m to 4000 m indicate that it is possible to choose an area threshold that will produce minimal differences in average network flow lengths across this range of scales. Flow direction grids at a 4 km resolution have been produced for the conterminous United States.

SU-E-T-579: Impact of Cylinder Size in High-Dose Rate Brachytherapy (HDRBT) for Primary Cancer in the Vagina

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

Zhang, H; Gopalakrishnan, M; Lee, P

2014-06-01

Purpose: To evaluate the dosimetric impact of cylinder size in high dose rate Brachytherapy for primary vaginal cancers. Methods: Patients treated with HDR vaginal vault radiation in a list of cylinders ranging from 2.5 to 4 cm in diameter at 0.5 cm increment were analyzed. All patients’ doses were prescribed at the 0.5 cm from the vaginal surface with different treatment lengths. A series of reference points were created to optimize the dose distribution. The fraction dose was 5.5 Gy, the treatment was repeated for 4 times in two weeks. A cylinder volume was contoured in each case according tomore » the prescribed treatment length, and then expanded to 5 mm to get a volume Cylinder-5mm-exp. A volume of PTV-Eval was obtained by subtracting the cylinder volume from the Cylinder-5mm-exp. The shell volume, PTV-Eval serves as the target volume for dosimetric evaluation. Results: DVH curves and average doses of PTV-Eval were obtained. Our results indicated that the DVH curves shifted toward higher dose side when larger cylinder was used instead of smaller ones. When 3.0 cm cylinder was used instead of 2.5 cm, for 3.0 cm treatment length, the average dose only increased 1%, from 790 to 799 cGy. However, the average doses for 3.5 and 4 cm cylinders respectively are 932 and 1137 cGy at the same treatment length. For 5.0 cm treatment length, the average dose is 741 cGy for 2.5 cm cylinder, and 859 cGy for 3 cm cylinder. Conclusion: Our data analysis suggests that for the vaginal intracavitary HDRBT, the average dose is at least 35% larger than the prescribed dose in the studied cases; the size of the cylinder will impact the dose delivered to the target volume. The cylinder with bigger diameter tends to deliver larger average dose to the PTV-Eval.« less

Effects of Telomerase and Telomere Length on Epidermal Stem Cell Behavior

NASA Astrophysics Data System (ADS)

Flores, Ignacio; Cayuela, María L.; Blasco, María A.

2005-08-01

A key process in organ homeostasis is the mobilization of stem cells out of their niches. We show through analysis of mouse models that telomere length, as well as the catalytic component of telomerase, Tert, are critical determinants in the mobilization of epidermal stem cells. Telomere shortening inhibited mobilization of stem cells out of their niche, impaired hair growth, and resulted in suppression of stem cell proliferative capacity in vitro. In contrast, Tert overexpression in the absence of changes in telomere length promoted stem cell mobilization, hair growth, and stem cell proliferation in vitro. The effects of telomeres and telomerase on stem cell biology anticipate their role in cancer and aging.

DNA confinement in nanochannels: physics and biological applications

NASA Astrophysics Data System (ADS)

Reisner, Walter; Pedersen, Jonas N.; Austin, Robert H.

2012-10-01

DNA is the central storage molecule of genetic information in the cell, and reading that information is a central problem in biology. While sequencing technology has made enormous advances over the past decade, there is growing interest in platforms that can readout genetic information directly from long single DNA molecules, with the ultimate goal of single-cell, single-genome analysis. Such a capability would obviate the need for ensemble averaging over heterogeneous cellular populations and eliminate uncertainties introduced by cloning and molecular amplification steps (thus enabling direct assessment of the genome in its native state). In this review, we will discuss how the information contained in genomic-length single DNA molecules can be accessed via physical confinement in nanochannels. Due to self-avoidance interactions, DNA molecules will stretch out when confined in nanochannels, creating a linear unscrolling of the genome along the channel for analysis. We will first review the fundamental physics of DNA nanochannel confinement—including the effect of varying ionic strength—and then discuss recent applications of these systems to genomic mapping. Apart from the intense biological interest in extracting linear sequence information from elongated DNA molecules, from a physics view these systems are fascinating as they enable probing of single-molecule conformation in environments with dimensions that intersect key physical length-scales in the 1 nm to 100 µm range.

DNA confinement in nanochannels: physics and biological applications.

PubMed

Reisner, Walter; Pedersen, Jonas N; Austin, Robert H

2012-10-01

DNA is the central storage molecule of genetic information in the cell, and reading that information is a central problem in biology. While sequencing technology has made enormous advances over the past decade, there is growing interest in platforms that can readout genetic information directly from long single DNA molecules, with the ultimate goal of single-cell, single-genome analysis. Such a capability would obviate the need for ensemble averaging over heterogeneous cellular populations and eliminate uncertainties introduced by cloning and molecular amplification steps (thus enabling direct assessment of the genome in its native state). In this review, we will discuss how the information contained in genomic-length single DNA molecules can be accessed via physical confinement in nanochannels. Due to self-avoidance interactions, DNA molecules will stretch out when confined in nanochannels, creating a linear unscrolling of the genome along the channel for analysis. We will first review the fundamental physics of DNA nanochannel confinement--including the effect of varying ionic strength--and then discuss recent applications of these systems to genomic mapping. Apart from the intense biological interest in extracting linear sequence information from elongated DNA molecules, from a physics view these systems are fascinating as they enable probing of single-molecule conformation in environments with dimensions that intersect key physical length-scales in the 1 nm to 100 µm range.

Highly sensitive sites for guanine-O6 ethylation in rat brain DNA exposed to N-ethyl-N-nitrosourea in vivo.

PubMed Central

Nehls, P; Rajewsky, M F; Spiess, E; Werner, D

1984-01-01

Brain chromosomal DNA isolated from fetal BDIX-rats 1 h after i.v. administration of the ethylating N-nitroso carcinogen N-ethyl-N-nitrosourea (75 micrograms/g body weight), statistically contained one molecule of O6-ethyl-2'-deoxyguanosine (O6-EtdGuo) per 81 micron of DNA, as determined in enzymatic DNA hydrolysates by competitive radio-immunoassay using a high-affinity anti-(O6-EtdGuo) monoclonal antibody (ER-6). After fragmentation of the DNA by the restriction enzyme AluI (average fragment length, Lav = 0.28 micron = 970 bp; length range, Lr = 1.87-0.02 micron = 6540 - 60 bp), a small (approximately 2%) fraction of DNA enriched in specific polypeptides tightly associated with DNA was separated from the bulk DNA by a glass fiber binding technique. As analyzed by immune electron microscopy, approximately 1% of the DNA molecules in this fraction contained clusters of 2-10 (O6-EtdGuo)-antibody binding sites (ABS). On the cluster-bearing fragments (Lav, 0.85 micron +/- 0.50 micron S.D.; corresponding to 2970 +/- 1760 bp) the average ABS-ABS interspace distance was 110 nm (= 390 bp; range approximately 9-600 nm), indicating a highly non-random distribution of O6-EtdGuo in target cell DNA. Images Fig. 2. PMID:6370677

Photoreceptor disc shedding in the living human eye

PubMed Central

Kocaoglu, Omer P.; Liu, Zhuolin; Zhang, Furu; Kurokawa, Kazuhiro; Jonnal, Ravi S.; Miller, Donald T.

2016-01-01

Cone photoreceptors undergo a daily cycle of renewal and shedding of membranous discs in their outer segments (OS), the portion responsible for light capture. These physiological processes are fundamental to maintaining photoreceptor health, and their dysfunction is associated with numerous retinal diseases. While both processes have been extensively studied in animal models and postmortem eyes, little is known about them in the living eye, in particular human. In this study, we report discovery of the optical signature associated with disc shedding using a method based on adaptive optics optical coherence tomography (AO-OCT) in conjunction with post-processing methods to track and monitor individual cone cells in 4D. The optical signature of disc shedding is characterized by an abrupt transient loss in the cone outer segment tip (COST) reflection followed by its return that is axially displaced anteriorly. Using this signature, we measured the temporal and spatial properties of shedding events in three normal subjects. Average duration of the shedding event was 8.8 ± 13.4 minutes, and average length loss of the OS was 2.1 μm (7.0% of OS length). Prevalence of cone shedding was highest in the morning (14.3%) followed by the afternoon (5.7%) and evening (4.0%), with load distributed across the imaged patch. To the best of our knowledge these are the first images of photoreceptor disc shedding in the living retina. PMID:27895995

[Ultrasonographic evaluation of the uterine cervix length remaining after LOOP-excision].

PubMed

Robert, A-L; Nicolas, F; Lavoué, V; Henno, S; Mesbah, H; Porée, P; Levêque, J

2014-04-01

To assess whether there is a correlation between the length of a conization specimen and the length of the cervix measured by vaginal ultrasonography after the operation Prospective observational study including patients less than 45 years with measurement of cervical length before and the day of the conization, and measuring the histological length of the specimen. Among the 40 patients enrolled, the average ultrasound measurements before conization was 26.9 mm (± 4.9 mm) against 18.1mm (± 4.4mm) after conization with a mean difference of 8.8mm (± 2.4mm) (difference statistically significant P<.0001). The extent of histological specimen was 9 mm (± 2.2mm) on average. A correlation between ultrasound and histological measurements with a correlation coefficient R=0.85 was found statistically significant (P<0.0001). Moreover, the rate of cervix length remove by loop-excision in our series is 33% (± 8.5%). A good correlation between the measurements of the specimen and the cervical ultrasound length before and after conization was found, as a significant reduction in cervical length after conization. The precise length of the specimen should be known in case of pregnancy and the prevention of prematurity due to conization rests on selected indications and efficient surgical technique. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Boundary-based cellwise OPC for standard-cell layouts

NASA Astrophysics Data System (ADS)

Pawlowski, David M.; Deng, Liang; Wong, Martin D. F.

2007-03-01

Model based optical proximity correction (OPC) has become necessary at 90nm technology node. Cellwise OPC is an attractive technique to reduce the mask data size as well as the prohibitive runtime of full-chip OPC. As feature dimensions have gotten smaller, the radius of influence for edge features has extended further into neighboring cells such that it is no longer sufficient to perform cellwise OPC independent of neighboring cells, especially for the critical layers. The methodology described in this work accounts for features in neighboring cells and allows a cellwise approach to be applied to cells with a printed gate length of 45nm with the projection that it can also be applied to future technology nodes. OPC-ready cells are generated at library creation (independent of placement) using a boundary-based technique. Each cell has a tractable number of OPC-ready versions due to an intelligent characterization of standard cell layout features. Results are very promising: the average edge placement error (EPE) for all metal1 features in 100 layouts is 0.731nm which is less than 1% of metal1 width; the maximum EPE for poly features reduced to 1/3, compared to cellwise OPC without considering boundaries, creating similar levels of lithographic accuracy while obviating any of the drawbacks inherent in layout specific full-chip model-based OPC.

Growing Neural PC-12 Cell on Crosslinked Silica Aerogels Increases Neurite Extension in the Presence of an Electric Field.

PubMed

Lynch, Kyle J; Skalli, Omar; Sabri, Firouzeh

2018-04-20

Externally applied electrical stimulation (ES) has been shown to enhance the nerve regeneration process and to influence the directionality of neurite outgrowth. In addition, the physical and chemical properties of the substrate used for nerve-cell regeneration is critical in fostering regeneration. Previously, we have shown that polyurea-crosslinked silica aerogels (PCSA) exert a positive influence on the extension of neurites by PC-12 cells, a cell-line model widely used to study neurite extension and electrical excitability. In this work, we have examined how an externally applied electric field (EF) influences the extension of neurites in PC-12 cells grown on two substrates: collagen-coated dishes versus collagen-coated crosslinked silica aerogels. The externally applied direct current (DC) bias was applied in vitro using a custom-designed chamber containing polydimethysiloxane (PDMS) embedded copper electrodes to create an electric field across the substrate for the cultured PC-12 cells. Results suggest orientation preference towards the anode, and, on average, longer neurites in the presence of the applied DC bias than with 0 V DC bias. In addition, neurite length was increased in cells grown on silica-crosslinked aerogel when compared to cells grown on regular petri-dishes. These results further support the notion that PCSA is a promising material for nerve regeneration.

Increased delivery stride length places greater loads on the ankle joint in elite male cricket fast bowlers.

PubMed

Spratford, Wayne; Hicks, Amy

2014-01-01

The purpose of this study was to investigate the effect stride length has on ankle biomechanics of the leading leg with reference to the potential risk of injury in cricket fast bowlers. Ankle joint kinematic and kinetic data were collected from 51 male fast bowlers during the stance phase of the final delivery stride. The bowling cohort comprised national under-19, first class and international-level athletes. Bowlers were placed into either Short, Average or Long groups based on final stride length, allowing statistical differences to be measured. A multivariate analysis of variance with a Bonferroni post-hoc correction (α = 0.05) revealed significant differences between peak plantarflexion angles (Short-Long P = 0.005, Average and Long P = 0.04) and negative joint work (Average-Long P = 0.026). This study highlighted that during fast bowling the ankle joint of the leading leg experiences high forces under wide ranges of movement. As stride length increases, greater amounts of negative work and plantarflexion are experienced. These increases place greater loads on the ankle joint and move the foot into positions that make it more susceptible to injuries such as posterior impingement syndrome.

Techniques for small-bone lengthening in congenital anomalies of the hand and foot.

PubMed

Minguella, J; Cabrera, M; Escolá, J

2001-10-01

The purpose of this study is to analyse three different lengthening techniques used in 31 small bones for congenital malformations of the hand and foot: 15 metacarpals, 12 metatarsals, 1 foot stump and 3 spaces between a previously transplanted phalanx end of the carpus or the metacarpal. Progressive lengthening with an external fixator device was performed in 23 cases: the callus distraction (callotasis) technique was used in 15 cases, whereas in the other 8 cases the speed of lengthening was faster and the defect bridged with a bone graft as a second stage. In another eight cases, a one-stage lengthening was performed. In the callotasis group, the total length gained ranged from 9 mm to 30 mm and the percentage of lengthening obtained (compared with the initial bone length) averaged 53.4%; in the fast lengthening group, the length gained ranged from 8 mm to 15 mm, and the average percentage of lengthening was 53.1%; and in the one-stage group, the length gained ranged from 7 mm to 15 mm, and the average percentage of lengthening was 43%. The overall complication rate was 22.5%.

BRE facilitates skeletal muscle regeneration by promoting satellite cell motility and differentiation

PubMed Central

Xiao, Lihai; Lee, Kenneth Ka Ho

2016-01-01

ABSTRACT The function of the Bre gene in satellite cells was investigated during skeletal muscle regeneration. The tibialis anterior leg muscle was experimentally injured in Bre knockout mutant (BRE-KO) mice. It was established that the accompanying muscle regeneration was impaired as compared with their normal wild-type counterparts (BRE-WT). There were significantly fewer pax7+ satellite cells and smaller newly formed myofibers present in the injury sites of BRE-KO mice. Bre was required for satellite cell fusion and myofiber formation. The cell fusion index and average length of newly-formed BRE-KO myofibers were found to be significantly reduced as compared with BRE-WT myofibers. It is well established that satellite cells are highly invasive which confers on them the homing ability to reach the muscle injury sites. Hence, we tracked the migratory behavior of these cells using time-lapse microscopy. Image analysis revealed no difference in directionality of movement between BRE-KO and BRE-WT satellite cells but there was a significant decrease in the velocity of BRE-KO cell movement. Moreover, chemotactic migration assays indicated that BRE-KO satellite cells were significantly less responsive to chemoattractant SDF-1α than BRE-WT satellite cells. We also established that BRE normally protects CXCR4 from SDF-1α-induced degradation. In sum, BRE facilitates skeletal muscle regeneration by enhancing satellite cell motility, homing and fusion. PMID:26740569

Phenological research of climate changes in the north part of Lithuania by the phenological garden of Šiauliai University.

PubMed

Klimienė, Asta; Vainorienė, Rimanta; Klimas, Ramutis

2017-02-01

Šiauliai University Botanical Garden is a member of the International Phenological Garden network since 2005. It is the only one botanical garden in the East Europe that participated in the programme. In 2015, 18 species were observed. For research, data of 14 plants was used. The aim of this study is to estimate the responsiveness of the species of plants of the phenological garden to annual and monthly precipitation and temperature of the air. The main variables in this investigation were growing season length and the beginning of the growing season. In the period 2006-2015, the lowest annual air temperature was in 2010 (6.0 °C), and the highest was in 2015 (8.9 °C). The lowest precipitation was in 2015 (37.3 mm), and the highest was in 2012 (63.5 mm). The leanest regression among growing length, average annual precipitation, and air temperature showed that statistically significant correlation between growing length and average annual air temperature was found for nine plants, between growing length and precipitation was found for three plants, and between growing length and both factors was found for one plant, Salix smithiana, only. Due to the short evaluating period (2007-2015), consistent regression of the length of the growing season could not be found. The growing length of Betula pubescens sequentially increased. The average growing season of 14 plants starts on April 27 (±3), but for Corylus avellana, it is on April 26 (±3). Longevity of the growing season was the most related with precipitation for C. avellana in summer, autumn, and winter and with air temperature, Ribes alpinum and Salix acutifolia in summer and in autumn.

Does Day Length Affect Winter Bird Distribution? Testing the Role of an Elusive Variable

PubMed Central

Carrascal, Luis M.; Santos, Tomás; Tellería, José L.

2012-01-01

Differences in day length may act as a critical factor in bird biology by introducing time constraints in energy acquisition during winter. Thus, differences in day length might operate as a main determinant of bird abundance along latitudinal gradients. This work examines the influence of day length on the abundance of wintering crested tits (Lophophanes cristatus) in 26 localities of Spanish juniper (Juniperus thurifera) dwarf woodlands (average height of 5 m) located along a latitudinal gradient in the Spanish highlands, while controlling for the influence of food availability, minimum night temperature, habitat structure and landscape characteristics. Top regression models in the AIC framework explained 56% of variance in bird numbers. All models incorporated day length as the variable with the highest magnitude effect. Food availability also played an important role, although only the crop of ripe juniper fruits, but not arthropods, positively affected crested tit abundance. Differences in vegetation structure across localities had also a strong positive effect (average tree height and juniper tree density). Geographical variation in night temperature had no influence on crested tit distribution, despite the low winter temperatures reached in these dwarf forests. This paper demonstrates for the first time that winter bird abundance increases with day length after controlling for the effect of other environmental variables. Winter average difference in day length was only 10.5 minutes per day along the 1°47′ latitudinal interval (190 km) included in this study. This amount of time, which reaches 13.5 h accumulated throughout the winter season, appears to be large enough to affect the long-term energy budget of small passerines during winter and to shape the distribution of winter bird abundance under restrictive environmental conditions. PMID:22393442

High order cell-centered scheme totally based on cell average

NASA Astrophysics Data System (ADS)

Liu, Ze-Yu; Cai, Qing-Dong

2018-05-01

This work clarifies the concept of cell average by pointing out the differences between cell average and cell centroid value, which are averaged cell-centered value and pointwise cell-centered value, respectively. Interpolation based on cell averages is constructed and high order QUICK-like numerical scheme is designed for such interpolation. A new approach of error analysis is introduced in this work, which is similar to Taylor’s expansion.

Life history variation among four lake trout morphs at Isle Royale, Lake Superior

USGS Publications Warehouse

Hansen, Michael J.; Nate, Nancy A.; Muir, Andrew M.; Bronte, Charles R.; Zimmerman, Mara S.; Krueger, Charles C.

2016-01-01

Life history traits were compared among four morphs of lake trout at Isle Royale, Lake Superior. Of 738 lake trout caught at Isle Royale, 701 were assigned to a morph (119 humpers, 160 leans, 85 redfins, and 337 siscowets) using a combination of statistical analysis of head and body shape and visual assignment. On average, redfins were longer (544 mm), heavier (1,481 g), heavier at length (Wr = 94), more buoyant, and older (22 years) than siscowets (519 mm; 1,221 g; 90; 19 years), leans (479 mm; 854 g; 82; 13 years), and humpers (443 mm; 697 g; 87; 17 years). On average, leans grew from a younger age at length = 0 and shorter length at age = 0, at a faster early growth rate to a longer asymptotic length than the other three morphs, while redfins grew at a slower instantaneous rate and humpers grew to a shorter asymptotic length than other morphs. On average, leans were longer (562 mm) and older (15 years) at 50% maturity than redfins (427 mm, 12 years), siscowets (401 mm, 11 years), or humpers (394 mm, 13 years). Life history parameters did not differ between males and females within each morph. We conclude that differences in life history attributes of lean, humper, redfin, and siscowet morphs of lake trout are consistent with differential habitat use in waters around Isle Royale, Lake Superior.

Experimental Investigation of an Air-Cooled Turbine Operating in a Turbojet Engine at Turbine Inlet Temperatures up to 2500 F

NASA Technical Reports Server (NTRS)

Cochran, Reeves P.; Dengler, Robert P.

1961-01-01

An experimental investigation was made of an air-cooled turbine at average turbine inlet temperatures up to 2500 F. A modified production-model 12-stage axial-flow-compressor turbojet engine operating in a static sea-level stand was used as the test vehicle. The modifications to the engine consisted of the substitution of special combustor and turbine assemblies and double-walled exhaust ducting for the standard parts of the engine. All of these special parts were air-cooled to withstand the high operating temperatures of the investigation. The air-cooled turbine stator and rotor blades were of the corrugated-insert type. Leading-edge tip caps were installed on the rotor blades to improve leading-edge cooling by diverting the discharge of coolant to regions of lower gas pressure toward the trailing edge of the blade tip. Caps varying in length from 0.15- to 0.55-chord length were used in an attempt to determine the optimum cap length for this blade. The engine was operated over a range of average turbine inlet temperatures from about 1600 to about 2500 F, and a range of average coolant-flow ratios of 0.012 to 0.065. Temperatures of the air-cooled turbine rotor blades were measured at all test conditions by the use of thermocouples and temperature-indicating paints. The results of the investigation indicated that this type of blade is feasible for operation in turbojet engines at the average turbine inlet temperatures and stress levels tested(maximums of 2500 F and 24,000 psi, respectively). An average one-third-span blade temperature of 1300 F could be maintained on 0.35-chord tip cap blades with an average coolant-flow ratio of about 0.022 when the average turbine inlet temperature was 2500 F and cooling-air temperature was about 260 F. All of the leading-edge tip cap lengths improved the cooling of the leading-edge region of the blades, particularly at low average coolant-flow ratios. At high gas temperatures, such parts as the turbine stator and the combustor liners are likely to be as critical as the turbine rotor blades.

Cost analytic model to determine the least costly inpatient erythropoiesis stimulating therapy regimen.

PubMed

Sikand, Harminder; Decter, Adam; Greco, Tina; Watson, Sue H; Kang, Yoon Jun; Mody, Samir H; Piech, Catherine Tak; Duh, Mei Sheng; Naeem, Ayesha

2008-01-01

Unlike in outpatient settings, the comparative costs of epoetin alpha (EPO) and darbepoetin alpha (DARB) have not been evaluated broadly from the inpatient hospital perspective. To develop a cost analytic model comparing hospital inpatient costs for erythropoiesis stimulating therapies within the nephrology and oncology settings. A cost analytic model incorporating erythropoietic drug, pharmacy, and nursing costs was developed from the inpatient hospital perspective to evaluate comparative costs of EPO and DARB. Erythropoietic drug costs were calculated using unit wholesale acquisition cost multiplied by the number of units or micrograms while comparing the following dosing regimens: EPO 3 times weekly, EPO once weekly, and DARB once weekly. Pharmacy costs included dispensing and delivery costs, while nursing costs incorporated administration time costs; all were calculated by estimated fractional hours per activity multiplied by hourly wages. The total frequency of erythropoiesis stimulating therapy administrations was determined based on the average hospital length of stay. The first erythropoiesis stimulating therapy dose was assumed to occur on day 3 of hospitalization. For total inpatient costs, a weighted average was calculated across disease states. One-way sensitivity analyses were conducted by varying length of stay, day of initial erythropoiesis stimulating therapy dose, pharmacy and nursing costs, and once-weekly DARB dose. EPO 3 times weekly was the least costly regimen across all disease states evaluated. Threshold analysis indicated that the cost of once-weekly DARB regimens would have to be reduced by 37% to equal the cost of EPO 3 times weekly for an average length of stay. Sensitivity analyses did not considerably affect the results. EPO 3 times weekly was found to be the least costly erythropoiesis stimulating therapy regimen for nephrology and oncology inpatients for the average length of stay as well as most other lengths of stay considered. Once-weekly EPO was the least costly erythropoiesis stimulating therapy regimen for several other lengths of stay, while once-weekly DARB was never found to be the least costly regimen.

Dynamic quantitative analysis of adherent cell cultures by means of lens-free video microscopy

NASA Astrophysics Data System (ADS)

Allier, C.; Vincent, R.; Navarro, F.; Menneteau, M.; Ghenim, L.; Gidrol, X.; Bordy, T.; Hervé, L.; Cioni, O.; Bardin, S.; Bornens, M.; Usson, Y.; Morales, S.

2018-02-01

We present our implementation of lens-free video microscopy setup for the monitoring of adherent cell cultures. We use a multi-wavelength LED illumination together with a dedicated holographic reconstruction algorithm that allows for an efficient removal of twin images from the reconstructed phase image for densities up to those of confluent cell cultures (>500 cells/mm2). We thereby demonstrate that lens-free video microscopy, with a large field of view ( 30 mm2) can enable us to capture the images of thousands of cells simultaneously and directly inside the incubator. It is then possible to trace and quantify single cells along several cell cycles. We thus prove that lens-free microscopy is a quantitative phase imaging technique enabling estimation of several metrics at the single cell level as a function of time, for example the area, dry mass, maximum thickness, major axis length and aspect ratio of each cell. Combined with cell tracking, it is then possible to extract important parameters such as the initial cell dry mass (just after cell division), the final cell dry mass (just before cell division), the average cell growth rate, and the cell cycle duration. As an example, we discuss the monitoring of a HeLa cell cultures which provided us with a data-set featuring more than 10 000 cell cycle tracks and more than 2x106 cell morphological measurements in a single time-lapse.

Morphometric assessment of normal human ciliary body using ultrasound biomicroscopy.

PubMed

Okamoto, Yoshifumi; Okamoto, Fumiki; Nakano, Shinichiro; Oshika, Tetsuro

2017-12-01

To quantitatively assess the biometry of the ciliary body in normal human eyes using ultrasound biomicroscopy. We evaluated 85 eyes of 85 normal subjects (35 men and 50 women), whose age ranged from 11 to 86 years (mean ± SD, 56.8 ± 20.4 years). The eyes were assessed along the 3-, 6-, 9-, and 12-o'clock meridians relative to the center of the cornea. Clinical data were collected, including age, axial length, ciliary body length (CBL), ciliary body thickness (CBT), anterior chamber depth, iris root thickness, trabecular-iris angle, and scleral-ciliary process angle. Axial length was measured using A-scan ultrasonography. CBL and CBT tended to be larger in the superior than in the inferior quadrant, but the differences among the four quadrants were not statistically significant. The average CBL showed a significant positive correlation with the average CBT (r = 0.40, P < 0.001). Average CBL and CBT were significantly correlated with axial length (r = 0.33, P = 0.031; r = 0.46, P < 0.01 respectively). In addition, the average CBL was significantly correlated with anterior chamber depth (r = 0.23, P < 0.05), trabecular-iris angle (r = 0.29, P = 0.01), and scleral-ciliary process angle (r = 0.40, P < 0.001). Ultrasound biomicroscopic imaging demonstrated that the ciliary body is similar in size in all circumferences, and eyes with longer axial length have an elongated and thicker ciliary body. The values obtained in the present study may serve as standard clinical references.

Engineering of cell-laden gelatin-based microgels for cell delivery and immobilization in regenerative therapies.

PubMed

Blocki, Anna; Löper, Farina; Chirico, Nino; Neffe, Axel T; Jung, Friedrich; Stamm, Christof; Lendlein, Andreas

2017-01-01

Cell-based therapies often face the challenge of low cell retention and viability upon transplantation. Hence, biomaterials, which can immobilize transplanted cells, while at the same time support cell viability, are essential for successful clinical application. Noteworthy, biomaterials in the micrometer range such as microcapsules or microspheres have the advantage of a minimally invasive introduction into tissue.Hence, we established an approach to generate gelatin-based cell carriers in the form of microspherical hydrogels. Fibroblasts were microencapsulated in glycidylmethacrylate (GMA)-functionalized gelatin by photopolymerization. While the degree of GMA-functionalization was kept constant, the hydrogel cross-linking density was adjusted by varying the time of irradiation or the average gelatin-chain length.Stable microspheres were synthesized from 10 wt% GMA-gelatin solutions for all irradiation periods tested (0.5 -2 min). Evaluation of cell viability revealed that microgels with the same weight content of biopolymer but with decreased cross-linking densities and thus decreased storage and E modulus, resulted in best cell support. Noteworthy, encapsulated cells partially migrated out of the microspheres and attached to the spherical surface.10 wt% GMA-gelatin-based hydrogels with E moduli comparable to the native cellular niche proved to be a promising biomaterial suitable for the production of cell-laden microspheres and shall be evaluated further for biomedical application.

Energy-saving EPON Bandwidth Allocation Algorithm Supporting ONU's Sleep Mode

NASA Astrophysics Data System (ADS)

Zhang, Yinfa; Ren, Shuai; Liao, Xiaomin; Fang, Yuanyuan

2014-09-01

A new bandwidth allocation algorithm was presented by combining merits of the IPACT algorithm and the cyclic DBA algorithm based on the DBA algorithm for ONU's sleep mode. Simulation results indicate that compared with the normal mode ONU, the ONU's sleep mode can save about 74% of energy. The new algorithm has a smaller average packet delay and queue length in the upstream direction. While in the downstream direction, the average packet delay of the new algorithm is less than polling cycle Tcycle and the average queue length is less than the product of Tcycle and the maximum link rate. The new algorithm achieves a better compromise between energy-saving and ensuring quality of service.

Styrene maleic acid encapsulated raloxifene micelles for management of inflammatory bowel disease.

PubMed

Greish, Khaled; Taha, Safa; Jasim, Anfal; Elghany, Sara Abd; Sultan, Ameera; AlKhateeb, Ali; Othman, Manal; Jun, Fang; Taurin, Sebastien; Bakhiet, Moiz

2017-12-01

Inflammatory bowel disease (IBD) comprises a group of disorders that manifest through chronic inflammation of the colon and small intestine. Although the exact cause of IBD is still unclear, dysfunctional immunoregulation involving overproduction of inflammatory cytokines such as TNF-α, and IL-6 have been implicated in pathogenesis. Current therapy relies on immunosuppression, cytotoxic drugs, and monoclonal antibodies against TNF-α. These classes of drugs have severe side-effects, especially when used for long duration. Our previous work with raloxifene, a selective estrogen receptor modulator, has shown that the drug, and to a greater extent its micellar formulation, has a significant suppressive effect on NF-κB, an essential immune-regulator. This finding directed the current work towards testing the anti-inflammatory and immunomodulatory effects of raloxifene using cell lines, as well as testing the potential use of the styrene maleic acid (SMA) micelles loaded with raloxifene (SMA-Ral) against dextran sulfate sodium (DSS) induced colitis in an in vivo model of IBD. Treatment of MCF-7 cells with TNF-α was shown to protect the cells from the cytotoxic effect of raloxifene (42 vs. 10% cell death, with TNF-α. Treating CaCo-2 cells with both free and SMA-Ral improved cell survival after exposure to 2% DDS with significantly higher protection with SMA-Ral. Treatment of U-937 with SMA-Ral and free-Ral resulted in down-regulation of TNF-α, IL-1β, IL-6, and MIP1α, with greater inhibition of the SMA-Ral, compared to free Ral. Balb/c mice treated with raloxifene and SMA-Ral showed weight gain at 14 days, compared to the control group (122, and 115% respectively). Treatment with raloxifene prevented DSS-induced diarrhea in 6/6 of free raloxifene treated mice and in 5/6 mice treated with SMA-Ral. Control group of DSS-treated mice showed average colon length of 7.4 cm compared to 13 cm in the control group. The average colon length was 12.3 and 11.5 cm for raloxifene and SMA-Ral treated groups, respectively. Furthermore, inflammatory cytokines such as IL-6 and TNF-α were reduced in serum of animals treated with free-Ral and SMA-Ral. Raloxifene and its micellar formulation warrants further studies to understand their effect on the treatment of colitis. Graphical abstract SMA-Raloxifene preparation and its in vivo and in vitro effect on colitis.

TP53-dependent chromosome instability is associated with transient reductions in telomere length in immortal telomerase-positive cell lines

NASA Technical Reports Server (NTRS)

Schwartz, J. L.; Jordan, R.; Liber, H.; Murnane, J. P.; Evans, H. H.

2001-01-01

Telomere shortening in telomerase-negative somatic cells leads to the activation of the TP53 protein and the elimination of potentially unstable cells. We examined the effect of TP53 gene expression on both telomere metabolism and chromosome stability in immortal, telomerase-positive cell lines. Telomere length, telomerase activity, and chromosome instability were measured in multiple clones isolated from three related human B-lymphoblast cell lines that vary in TP53 expression; TK6 cells express wild-type TP53, WTK1 cells overexpress a mutant form of TP53, and NH32 cells express no TP53 protein. Clonal variations in both telomere length and chromosome stability were observed, and shorter telomeres were associated with higher levels of chromosome instability. The shortest telomeres were found in WTK1- and NH32-derived cells, and these cells had 5- to 10-fold higher levels of chromosome instability. The primary marker of instability was the presence of dicentric chromosomes. Aneuploidy and other stable chromosome alterations were also found in clones showing high levels of dicentrics. Polyploidy was found only in WTK1-derived cells. Both telomere length and chromosome instability fluctuated in the different cell populations with time in culture, presumably as unstable cells and cells with short telomeres were eliminated from the growing population. Our results suggest that transient reductions in telomere lengths may be common in immortal cell lines and that these alterations in telomere metabolism can have a profound effect on chromosome stability. Copyright 2000 Wiley-Liss, Inc.

Flux-induced Nernst effect in low-dimensional superconductors

NASA Astrophysics Data System (ADS)

Berger, Jorge

2017-02-01

A method is available that enables consistent study of the stochastic behavior of a system that obeys purely diffusive evolution equations. This method has been applied to a superconducting loop with nonuniform temperature, with average temperature close to Tc. It is found that a flux-dependent average potential difference arises along the loop, proportional to the temperature gradient and most pronounced in the direction perpendicular to this gradient. The largest voltages were obtained for fluxes close to 0.3Φ0, average temperatures slightly below the critical temperature, thermal coherence length of the order of the perimeter of the ring, BCS coherence length that is not negligible in comparison to the thermal coherence length, and short inelastic scattering time. This effect is entirely due to thermal fluctuations. It differs essentially from the usual Nernst effect in bulk superconductors, that is induced by magnetic field rather than by magnetic flux. We also study the effect of confinement in a 2D mesoscopic film.

Associations of Nurse Staffing and Education With the Length of Stay of Surgical Patients.

PubMed

Cho, Eunhee; Park, Jeongyoung; Choi, Miyoung; Lee, Hye Sun; Kim, Eun-Young

2018-03-01

To examine the association of nurse staffing and education with the length of stay of surgical patients in acute care hospitals in South Korea. A cross-sectional survey design was used for a nurse survey in acute hospitals collected between 2008 and 2009. The survey data (N = 1,665) were linked with patient discharge data (N = 113,438) and hospital facility data from 58 hospitals with 100 or more beds in South Korea. The dependent variable was the length of stay, that is, the number of days a patient remained in the hospital. The independent variables were nurse staffing (number of patients per nurse) and nurses' education level (percentage of nurses with a bachelor of science in nursing [BSN] degree). A multilevel analysis was used to analyze the associations of nurse staffing and education level with the length of stay by controlling for both hospital and patient characteristics. The average proportion of nurses with a BSN in all the hospitals was 30.86%, while the average number of patients per nurse was 14.31. The median length of hospital stay for patients was about 7 days. The multilevel analysis showed that nurse staffing and nurse education level were significantly associated with the length of stay of surgical patients in acute care hospitals. A 10% increase in the average number of patients per nurse increased the length of stay by 0.284 days (p = .037). When the number of nurses with a BSN was increased by 1%, the length of stay decreased by 0.42 days (p = .025). Nurse staffing and nurses' education levels were significantly associated with the length of stay of surgical patients in South Korean hospitals. The findings from this study suggest that the South Korea healthcare system should develop appropriate strategies to improve the nurse staffing and education levels to ensure high-quality patient care in hospitals. Healthcare policymakers and nurse managers need to modify adequate nurse staffing and education levels in order to reduce the length of stay of patients. © 2017 Sigma Theta Tau International.

EFFECTS OF MINERAL CONTENT ON THE FRACTURE PROPERTIES OF EQUINE CORTICAL BONE IN DOUBLE-NOTCHED BEAMS

PubMed Central

McCormack, Jordan; Stover, Susan M.; Gibeling, Jeffery C.; Fyhrie, David P.

2012-01-01

We recently developed a method to measure cortical bone fracture initiation toughness using a double-notched beam in four-point bending. This method was used to test the hypothesis that mineralization around the two notch roots is correlated with fracture toughness and crack extension (physical damage). Total energy absorbed to failure negatively correlated with average mineralization of the beam (r2=0.62), but not with notch root mineralization. Fracture initiation toughness was positively correlated to mineralization at the broken notch root (r2=0.34). Crack length extension at the unbroken notch was strongly negatively correlated with the average mineralization of the notch roots (r2=0.81) whereas crack length extension at the broken notch did not correlate with any of the mineralization measurements. Mineralization at the notch roots and the average mineralization contributed independently to the mechanical and damage properties. The data are consistent with an hypothesis that a) high notch root mineralization results in less stable crack length extension but high force to initiate unstable crack propagation while b) higher average mineralization leads to low post-yield (and total) energy absorption to failure. PMID:22394589

Monitoring Poisson observations using combined applications of Shewhart and EWMA charts

NASA Astrophysics Data System (ADS)

Abujiya, Mu'azu Ramat

2017-11-01

The Shewhart and exponentially weighted moving average (EWMA) charts for nonconformities are the most widely used procedures of choice for monitoring Poisson observations in modern industries. Individually, the Shewhart EWMA charts are only sensitive to large and small shifts, respectively. To enhance the detection abilities of the two schemes in monitoring all kinds of shifts in Poisson count data, this study examines the performance of combined applications of the Shewhart, and EWMA Poisson control charts. Furthermore, the study proposes modifications based on well-structured statistical data collection technique, ranked set sampling (RSS), to detect shifts in the mean of a Poisson process more quickly. The relative performance of the proposed Shewhart-EWMA Poisson location charts is evaluated in terms of the average run length (ARL), standard deviation of the run length (SDRL), median run length (MRL), average ratio ARL (ARARL), average extra quadratic loss (AEQL) and performance comparison index (PCI). Consequently, all the new Poisson control charts based on RSS method are generally more superior than most of the existing schemes for monitoring Poisson processes. The use of these combined Shewhart-EWMA Poisson charts is illustrated with an example to demonstrate the practical implementation of the design procedure.

Image averaging of flexible fibrous macromolecules: the clathrin triskelion has an elastic proximal segment.

PubMed

Kocsis, E; Trus, B L; Steer, C J; Bisher, M E; Steven, A C

1991-08-01

We have developed computational techniques that allow image averaging to be applied to electron micrographs of filamentous molecules that exhibit tight and variable curvature. These techniques, which involve straightening by cubic-spline interpolation, image classification, and statistical analysis of the molecules' curvature properties, have been applied to purified brain clathrin. This trimeric filamentous protein polymerizes, both in vivo and in vitro, into a wide range of polyhedral structures. Contrasted by low-angle rotary shadowing, dissociated clathrin molecules appear as distinctive three-legged structures, called "triskelions" (E. Ungewickell and D. Branton (1981) Nature 289, 420). We find triskelion legs to vary from 35 to 62 nm in total length, according to an approximately bell-shaped distribution (mu = 51.6 nm). Peaks in averaged curvature profiles mark hinges or sites of enhanced flexibility. Such profiles, calculated for each length class, show that triskelion legs are flexible over their entire lengths. However, three curvature peaks are observed in every case: their locations define a proximal segment of systematically increasing length (14.0-19.0 nm), a mid-segment of fixed length (approximately 12 nm), and a rather variable end-segment (11.6-19.5 nm), terminating in a hinge just before the globular terminal domain (approximately 7.3 nm diameter). Thus, two major factors contribute to the overall variability in leg length: (1) stretching of the proximal segment and (2) stretching of the end-segment and/or scrolling of the terminal domain. The observed elasticity of the proximal segment may reflect phosphorylation of the clathrin light chains.

Observations of fibropapillomatosis in green turtles (Chelonia mydas) in Indonesia.

PubMed

Adnyana, W; Ladds, P W; Blair, D

1997-10-01

To determine the prevalence and manifestations of fibropapillomatosis in green turtles in Indonesia, to identify any relationship between fibropapillomatosis and concurrent parasitic infection, to ascertain the effect of fibropapillomatosis on health, and to examine whether environment might have an effect on the prevalence of fibropapillomatosis. 4407 green turtles (Chelonia mydas) and 401 hawksbill turtles (Eretmochelys imbricata) were examined. The occurrence of fibropapillomatosis was correlated with sex, maturity, curved carapace length, body weight/curved carapace length ratio, the number and distribution of tumours on the skin, parasite burdens, some haematological variables and the region of capture. Fibropapillomatosis was seen only in green turtles, and the overall prevalence in these was 21.5%. This prevalence increased with the curved carapace length up to 85 cm. The average number of tumours per affected turtle was 5 +/- SD 4.1 (range, 1 to 29), and was negatively correlated with the body weight/curved carapace length ratio (rs = -0.8; P = 0.001). The red blood cell count in turtles with fibropapilloma was lower than in non-fibropapilloma turtles captured and examined at the same time (P = 0.001). The prevalence of fibropapilloma in turtles captured near densely populated, industrial regions (26.3%) was greater than in turtles from sparsely populated areas (17.7%). Fibropapillomatosis in green sea turtles in Indonesia is of moderate occurrence: young mature turtles (curved carapace length = 85 cm) are most frequently affected. Fibropapilloma adversely affects health of turtles. Fluke infestation seems not to be a causal factor, but viral infection, perhaps with concurrent stress of environmental origin, seems likely.

Can Tissue Cilia Lengths and Urine Cilia Proteins Be Markers of Kidney Diseases?

PubMed

Park, Kwon Moo

2018-05-01

The primary cilium is an organelle which consists of a microtubule in the core and a surrounding cilia membrane, and has long been recognized as a "vestigial organelle". However, new evidence demonstrates that the primary cilium has a notable effect on signal transduction in the cell and is associated with some genetic and non-genetic diseases. In the kidney, the primary cilium protrudes into the Bowman's space and the tubular lumen from the apical side of epithelial cells. The length of primary cilia is dynamically altered during the normal cell cycle, being shortened by retraction into the cell body at the entry of cell division and elongated at differentiation. Furthermore, the length of primary cilia is also dynamically changed in the cells, as a result and/or cause, during the progression of various kidney diseases including acute kidney injury and chronic kidney disease. Notably, recent data has demonstrated that the shortening of the primary cilium in the cell is associated with fragmentation, apart from retraction into the cell body, in the progression of diseases and that the fragmented primary cilia are released into the urine. This data reveals that the alteration of primary cilia length could be related to the progression of diseases. This review will consider if primary cilia length alteration is associated with the progression of kidney diseases and if the length of tissue primary cilia and the presence or increase of cilia proteins in the urine is indicative of kidney diseases.

Realizing the Translational Potential of Telomere Length Variation as a Tissue Based Prognostic Marker for Prostate Cancer

DTIC Science & Technology

2016-10-01

Award Number: W81XWH-12-1-0545 TITLE: Realizing the Translational Potential of Telomere Length Variation as a Tissue- Based Prognostic Marker for...30 Sep 2015 - 29 Sep 2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Realizing the Translational Potential of Telomere Length Variation as a Tissue...HPFS), whether the combination of telomere length variability in prostate cancer cells and short telomere length in cancer-associated stromal cells is

A STUDY OF SOME SOFTWARE PARAMETERS IN TIME-SHARING SYSTEMS.

DTIC Science & Technology

A review is made of some existing time-sharing computer systems and an exploration of various software characteristics is conducted. This...of the various parameters upon the average response cycle time, the average number in the queue awaiting service , the average length of time a user is

Limb lengthening in short stature patients.

PubMed

Aldegheri, R; Dall'Oca, C

2001-07-01

A series of 140 patients with short stature operated on for limb lengthening (80 had achondroplasia, 20 had hypochondroplasia, 20 had Turner syndrome, 10 had idiopathic short stature due to an undemonstrated cause, 5 regarded their stature as too short, and 5 had a psychopathic personality due to dysmorphophobia that had developed because of their short stature) was reviewed. All patients underwent symmetric lengthening of both femora and tibiae; 10 of these achondroplastic patients underwent lengthening of the humeri. We carried out the 580 lengthening procedures by means of three different surgical techniques: 440 callotasis, 120 chondrodiatasis and 20 mid-shaft osteotomy. In the 130 patients with a disproportionate short stature, the average gain in length was 18.2 +/- 3.93 cm: 43.8% had complications and 3.8% had sequelae; the average treatment time was 31 months. In the 10 patients with proportionate short stature, the average gain in length was 10.8 +/- 1.00 cm: 4 experienced complications and none had sequelae; the average treatment time was 21 months. Patients who underwent lengthening of the upper limbs experienced an average gain in length of 10.2 +/- 1.25 cm: the average treatment time was 9 months and none of them experienced any complications or sequelae. The authors discuss how difficult it is to achieve the benefits of this surgery: they underline the strong commitment on the part of the patients and their families, the time in the hospital, the number of operations and, above all, the severity of those permanent sequelae that occurred.

The twin cell model and its excellence in determining the glass transition temperature of thin film metallic glass

NASA Astrophysics Data System (ADS)

Kanjilal, Baishali; Iram, Samreen; Das, Atreyee; Chakrabarti, Haimanti

2018-05-01

This work reports a novel two dimensional approach to the theoretical computation of the glass transition temperature in simple hypothetical icosahedral packed structures based on Thin Film metallic glasses using liquid state theories in the realm of transport properties. The model starts from Navier-Stokes equation and evaluates the statistical average velocity of each different species of atom under the condition of ensemble equality to compute diffusion lengths and the diffusion coefficients as a function of temperature. The additional correction brought in is that of the limited states due to tethering of one nodule vis -a-vis the others. The movement of the molecules use our Twin Cell Model a typical model pertinent for modeling chain motions. A temperature viscosity correction by Cohen and Grest is included through the temperature dependence of the relaxation times for glass formers.

Biopolymer dynamics driven by helical flagella

NASA Astrophysics Data System (ADS)

Balin, Andrew K.; Zöttl, Andreas; Yeomans, Julia M.; Shendruk, Tyler N.

2017-11-01

Microbial flagellates typically inhabit complex suspensions of polymeric material which can impact the swimming speed of motile microbes, filter feeding of sessile cells, and the generation of biofilms. There is currently a need to better understand how the fundamental dynamics of polymers near active cells or flagella impacts these various phenomena, in particular, the hydrodynamic and steric influence of a rotating helical filament on suspended polymers. Our Stokesian dynamics simulations show that as a stationary rotating helix pumps fluid along its long axis, polymers migrate radially inward while being elongated. We observe that the actuation of the helix tends to increase the probability of finding polymeric material within its pervaded volume. This accumulation of polymers within the vicinity of the helix is stronger for longer polymers. We further analyze the stochastic work performed by the helix on the polymers and show that this quantity is positive on average and increases with polymer contour length.

Structure and dye-sensitized solar cell application of TiO2 nanotube arrays fabricated by the anodic oxidation method

NASA Astrophysics Data System (ADS)

Ok, Seon-Yeong; Cho, Kwon-Koo; Kim, Ki-Won; Ryu, Kwang-Sun

2010-05-01

Well-ordered TiO2 nanotube arrays were fabricated by the potentiostatic anodic oxidation method using pure Ti foil as a working electrode and ethylene glycol solution as an electrolyte with the small addition of NH4F and H2O. The influence of anodization temperature and time on the morphology and formation of TiO2 nanotube arrays was examined. The TiO2 nanotube arrays were applied as a photoelectrode to dye-sensitized solar cells. Regardless of anodizing temperature and time, the average diameter and wall thickness of TiO2 nanotube arrays show a similar value, whereas the length increases with decreasing reaction temperature. The conversion efficiency is very low, which is due to a morphology breaking of the TiO2 nanotube arrays in the manufacturing process of a photoelectrode.

Mitochondrial DNA typing from human axillary, pubic and head hair shafts - success rates and sequence comparisons.

PubMed

Pfeiffer, H; Hühne, J; Ortmann, C; Waterkamp, K; Brinkmann, B

1999-01-01

The analysis of mitochondrial DNA (mtDNA) from shed hairs has gained high importance in forensic casework since telogen hairs are one of the most common types of evidence left at the crime scene. In this systematic study of hair shafts from 20 individuals, the correlation of mtDNA recovery with hair morphology (length, diameter, volume, colour), with sex, and with body localisation (head, armpit, pubis) was investigated. The highest average success rate of hypervariable region 1 (HV 1) sequencing was found in head hair shafts (75%) followed by pubic (66%) and axillary hair shafts (52%). No statistically significant correlation between morphological parameters or sex and the success rate of sequencing was found. MtDNA sequences of buccal cells, head, pubic and axillary hair shafts did not show intraindividual differences. Heteroplasmic base positions were observed neither in the hair shafts nor in control samples of buccal cells.

Significantly lengthened telomere in granulosa cells from women with polycystic ovarian syndrome (PCOS).

PubMed

Wei, Duo; Xie, Juanke; Yin, Baoli; Hao, Haoying; Song, Xiaobing; Liu, Qi; Zhang, Cuilian; Sun, Yingpu

2017-07-01

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy among women at reproductive age. However, its etiology remains poorly understood. Recent studies indicated that telomere length was related to PCOS. However, the association between telomere length and PCOS has only been shown in leucocytes and remained controversial across different studies. To clarify the association between telomere length and PCOS, the current study interrogated telomere length not only in leucocytes, but also in follicular granulosa cells, which is essential for folliculogenesis and steroidogenesis. Seventy-five patients with PCOS and 81 controls with mechanical infertility undergoing their first in vitro fertilization cycle were enrolled. Their peripheral blood and granulosa cells were collected on the oocyte retrieval day. Telomere length of both leucocytes in the blood and granulosa cells was assayed by quantitative polymerase chain reaction. No significant difference was found in the leucocyte telomere length between controls and PCOS patients (0.99 ± 0.44 vs. 1.00 ± 0.38, p = 0.93). Interestingly, when comparing telomere length in granulosa cells between controls and PCOS subjects, significantly lengthened telomere length was found in PCOS subjects (1.00 ± 0.37 vs. 1.57±0.67, p < 0.0001). After adjustments for age and body mass index, the p value remained significant (p < 0.0001). This finding reinforced the association between telomere abnormalities and PCOS. Given the importance of telomere length in cellular proliferation, our findings provided novel insights into the pathophysiology of PCOS that abnormalities in telomere length possibly disturb folliculogenesis and subsequently result in PCOS.

A Case Study to Improve Emergency Room Patient Flow at Womack Army Medical Center

DTIC Science & Technology

2009-06-01

use just the previous month, moving average 2-month period ( MA2 ) uses the average from the previous two months, moving average 3-month period (MA3...ED prior to discharge by provider) MA2 /MA3/MA4 - moving averages of 2-4 months in length MAD - mean absolute deviation (measure of accuracy for

Increased telomere length and proliferative potential in peripheral blood mononuclear cells of adults of different ages stimulated with concanavalin A

PubMed Central

2013-01-01

Background Recently, a direct correlation with telomere length, proliferative potential and telomerase activity has been found in the process of aging in peripheral blood cells. The objective of the study was to evaluate telomere length and proliferative potential in peripheral blood mononuclear cells (PBMCs) after stimulation with Concanavalin A (ConA) of young adults compared with older adults. Methods Blood samples were obtained from 20 healthy young males (20–25 years old) (group Y) and 20 males (60–65 years old) (group O). We compared PBMC proliferation before and after stimulation with ConA. DNA was isolated from cells separated before and after culture with ConA for telomeric measurement by real-time polymerase chain reaction. Results In vitro stimulation of PBMCs from young subjects induced an increase of telomere length as well as a higher replicative capacity of cell proliferation. Samples from older adults showed higher loss of telomeric DNA (p = 0.03) and higher levels of senescent (≤6.2 kb) telomeric DNA (p = 0.02) and displayed a marked decrease of proliferation capacity. Viability cell counts and CFSE tracking in 72-h-old cell cultures indicated that group O PBMCs (CD8+ and CD4+ T cells) underwent fewer mitotic cycles and had shorter telomeres than group Y (p = 0.04). Conclusions Our findings confirm that telomere length in older-age adults is shorter than in younger subjects. After stimulation with ConA, cells are not restored to the previous telomere length and undergo replicative senescence. This is in sharp contrast to the response observed in young adults after ConA stimulation where cells increase in telomere length and replicative capacity. The mechanisms involved in this phenomenon are not yet clear and merit further investigation. PMID:24063536

[Intestinal fungal diversity of sub-adult giant panda].

PubMed

Ai, Shengquan; Zhong, Zhijun; Peng, Guangneng; Wang, Chengdong; Luo, Yongjiu; He, Tingmei; Gu, Wuyang; Li, Caiwu; Li, Gangshi; Wu, Honglin; Liu, Xuehan; Xia, Yu; Liu, Yanhong; Zhou, Xiaoxiao

2014-11-04

The fungi diversity in the guts of five sub-adult giant pandas was analyzed. We analyzed the fungal internal transcribed spacer sequences (ITS) using restriction fragment length polymorphism (RFLP). ITS regions were amplified with fungal universal primers to construct ITS clone libraries. The fingerprints were analyzed by restriction fragment length polymorphism using the Hha I and Hae III enzymes. The cloned PCR products were analyzed by sequencing and diversities were demonstrated by phylogenetic tree. The gut fungi of 5 sub-adult giant pandas were mainly composed of Ascomycota (average of 46.24%), Basidiomycota ( average of 15.79%), unclassified (average of 29.14%), uncultured fungus (average of 8.83% ). Ascomycota was mainly composed of Saccharomycetes (average of 63.74%) and Dothideomycetes ( average of 35.91%); Basidiomycota was mainly composed of Tremellomycetes (average of 65.80%) and Microbotryomycetes (average of 33.15%). Four classes were mainly composed of Candida and Debaryomyces; Pleosporales and Myriangium; Cystofilobasidium and Trichosporon; Leucosporidium, and Leucosporidiella, whereas the proportions were different for each sample. Fungal flora existing in the intestines of sub-adult giant pandas expand our knowledge on the structure of the giant panda gut microbes and also help us to further study whether fungal flora can help giant pandas digest high-fiber foods.

Osteological Development of the Larvae and Juvenile of Bullhead torrent catfish, Liobagrus obesus

PubMed Central

Seo, Won-Il; Park, Jae-Min; Lee, Sung-Hun; Yoon, Seong Min; Hwang, Seon-Yeong; Han, Kyeong-Ho

2018-01-01

ABSTRACT This study was conducted to investigate the skeletal development of bullhead torrent catfish, Liobagrus obesus larvae and to utilize them as basic data for the taxonomic study of Liobagrus larvae. Skeletal development was observed by being divided into cranium, visceral skeleton, shoulder girdle bone, pelvic girdle bone and vertebra. On the first day after hatching, the pre-larvae had an average total length of 7.92 mm, and a line-shaped parasphenoid ossified in the cranium. In the jaw bone, the dentary supporting the lower jaw and the maxillary supporting the upper jaw were ossified. In the anterior abdominal vertebrae of the vertebra, seven centrums began to ossify and five neural spines ossified simultaneously. On the 3 day after hatching, pre-larvae had an average total length of 8.95 mm, and the prefrontal ossified in cranium. The number of abdominal vertebrae was increased to 14, and three parapophysis developed from the front side. On the 24th day after hatching, post-larvae had an average total length of 15.2 mm and the epural bone ossified in coccyx. The parhypural bone was ossified, and ossification of coccyx and pelvic girdle bone was completed. On the 30th day after hatching, the average total length of the juvenile was 17.8 mm, and the ossification of cranium and visceral skeleton was all completed while the preorbital and three suborbitals were ossified in the orbital region of the cranium. PMID:29707680

Constant volume gas cell optical phase-shifter

DOEpatents

Phillion, Donald W.

2002-01-01

A constant volume gas cell optical phase-shifter, particularly applicable for phase-shifting interferometry, contains a sealed volume of atmospheric gas at a pressure somewhat different than atmospheric. An optical window is present at each end of the cell, and as the length of the cell is changed, the optical path length of a laser beam traversing the cell changes. The cell comprises movable coaxial tubes with seals and a volume equalizing opening. Because the cell is constant volume, the pressure, temperature, and density of the contained gas do not change as the cell changes length. This produces an exactly linear relationship between the change in the length of the gas cell and the change in optical phase of the laser beam traversing it. Because the refractive index difference between the gas inside and the atmosphere outside is very much the same, a large motion must be made to change the optical phase by the small fraction of a wavelength that is required by phase-shifting interferometry for its phase step. This motion can be made to great fractional accuracy.

Heterogeneity and nearest-neighbor coupling can explain small-worldness and wave properties in pancreatic islets

NASA Astrophysics Data System (ADS)

Cappon, Giacomo; Pedersen, Morten Gram

2016-05-01

Many multicellular systems consist of coupled cells that work as a syncytium. The pancreatic islet of Langerhans is a well-studied example of such a microorgan. The islets are responsible for secretion of glucose-regulating hormones, mainly glucagon and insulin, which are released in distinct pulses. In order to observe pulsatile insulin secretion from the β-cells within the islets, the cellular responses must be synchronized. It is now well established that gap junctions provide the electrical nearest-neighbor coupling that allows excitation waves to spread across islets to synchronize the β-cell population. Surprisingly, functional coupling analysis of calcium responses in β-cells shows small-world properties, i.e., a high degree of local coupling with a few long-range "short-cut" connections that reduce the average path-length greatly. Here, we investigate how such long-range functional coupling can appear as a result of heterogeneity, nearest-neighbor coupling, and wave propagation. Heterogeneity is also able to explain a set of experimentally observed synchronization and wave properties without introducing all-or-none cell coupling and percolation theory. Our theoretical results highlight how local biological coupling can give rise to functional small-world properties via heterogeneity and wave propagation.

Normative Database and Color-code Agreement of Peripapillary Retinal Nerve Fiber Layer and Macular Ganglion Cell-inner Plexiform Layer Thickness in a Vietnamese Population.

PubMed

Perez, Claudio I; Chansangpetch, Sunee; Thai, Andy; Nguyen, Anh-Hien; Nguyen, Anwell; Mora, Marta; Nguyen, Ngoc; Lin, Shan C

2018-06-05

Evaluate the distribution and the color probability codes of the peripapillary retinal nerve fiber layer (RNFL) and macular ganglion cell-inner plexiform layer (GCIPL) thickness in a healthy Vietnamese population and compare them with the original color-codes provided by the Cirrus spectral domain OCT. Cross-sectional study. We recruited non-glaucomatous Vietnamese subjects and constructed a normative database for peripapillary RNFL and macular GCIPL thickness. The probability color-codes for each decade of age were calculated. We evaluated the agreement with Kappa coefficient (κ) between OCT color probability codes with Cirrus built-in original normative database and the Vietnamese normative database. 149 eyes of 149 subjects were included. The mean age of enrollees was 60.77 (±11.09) years, with a mean spherical equivalent of +0.65 (±1.58) D and mean axial length of 23.4 (±0.87) mm. Average RNFL thickness was 97.86 (±9.19) microns and average macular GCIPL was 82.49 (±6.09) microns. Agreement between original and adjusted normative database for RNFL was fair for average and inferior quadrant (κ=0.25 and 0.2, respectively); and good for other quadrants (range: κ=0.63-0.73). For macular GCIPL κ agreement ranged between 0.39 and 0.69. After adjusting with the normative Vietnamese database, the percent of yellow and red color-codes increased significantly for peripapillary RNFL thickness. Vietnamese population has a thicker RNFL in comparison with Cirrus normative database. This leads to a poor color-code agreement in average and inferior quadrant between the original and adjusted database. These findings should encourage to create a peripapillary RNFL normative database for each ethnicity.

Independent effects of step length and foot strike pattern on tibiofemoral joint forces during running.

PubMed

Bowersock, Collin D; Willy, Richard W; DeVita, Paul; Willson, John D

2017-10-01

The purpose of this study was to examine the effects of step length and foot strike pattern along with their interaction on tibiofemoral joint (TFJ) and medial compartment TFJ kinetics during running. Nineteen participants ran with a rear foot strike pattern at their preferred speed using a short (-10%), preferred, and long (+10%) step length. These step length conditions were then repeated using a forefoot strike pattern. Regardless of foot strike pattern, a 10% shorter step length resulted in decreased peak contact force, force impulse per step, force impulse per kilometre, and average loading rate at the TFJ and medial compartment, while a 10% increased step length had the opposite effects (all P < 0.05). A forefoot strike pattern significantly lowered TFJ and medial compartment TFJ average loading rates compared with a rear foot strike pattern (both <0.05) but did not change TFJ or medial compartment peak force, force impulse per step, or force impulse per km. The combination of a shorter step length and forefoot strike pattern produced the greatest reduction in peak medial compartment contact force (P < 0.05). Knowledge of these running modification effects may be relevant to the management or prevention of TFJ injury or pathology among runners.

Competitive advantage for multiple-memory strategies in an artificial market

NASA Astrophysics Data System (ADS)

Mitman, Kurt E.; Choe, Sehyo C.; Johnson, Neil F.

2005-05-01

We consider a simple binary market model containing N competitive agents. The novel feature of our model is that it incorporates the tendency shown by traders to look for patterns in past price movements over multiple time scales, i.e. multiple memory-lengths. In the regime where these memory-lengths are all small, the average winnings per agent exceed those obtained for either (1) a pure population where all agents have equal memory-length, or (2) a mixed population comprising sub-populations of equal-memory agents with each sub-population having a different memory-length. Agents who consistently play strategies of a given memory-length, are found to win more on average -- switching between strategies with different memory lengths incurs an effective penalty, while switching between strategies of equal memory does not. Agents employing short-memory strategies can outperform agents using long-memory strategies, even in the regime where an equal-memory system would have favored the use of long-memory strategies. Using the many-body 'Crowd-Anticrowd' theory, we obtain analytic expressions which are in good agreement with the observed numerical results. In the context of financial markets, our results suggest that multiple-memory agents have a better chance of identifying price patterns of unknown length and hence will typically have higher winnings.

Events of hospitalization among children with sickle cell disease.

PubMed

Fosdal, Marian B; Wojner-Alexandrov, Anne W

2007-08-01

Previous research has identified vaso-occlusive pain crisis as the most common reason for hospitalization among pediatric patients with sickle cell disease. We sought to identify contributors to hospitalization and length of stay (LOS) for this patient population. A descriptive design was used to determine factors associated with hospitalization and LOS for patients with sickle cell disease at an urban tertiary care pediatric hospital in the Midwest. Sickle cell disease as a principal or secondary diagnosis during calendar year 2003 was used to identify patients for study inclusion. Data were collected from subjects' medical records and the hospital accounting system. 72 African American subjects, ranging in age from infant to 24 years (mean = 10.3) met study inclusion criteria, and accounted for 186 hospitalizations. Sickle cell pain crisis was the most common diagnosis associated with hospitalization (n = 122). Adolescent age was significantly associated with longer LOS (r = .451; p<.001), and females stayed on average 2.1 days longer than male subjects (p = .001). Age and gender appear to be associated with LOS in pediatric patients with sickle cell disease, although specific factors underlying these findings remain unclear. Further research is necessary to determine how the complex interplay of social, cultural, developmental, and physiologic factors may contribute to the hospitalization experience of children and adolescents with sickle cell disease.

Diffusion lengths of silicon solar cells from luminescence images

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

Wuerfel, P.; Trupke, T.; Puzzer, T.

A method for spatially resolved measurement of the minority carrier diffusion length in silicon wafers and in silicon solar cells is introduced. The method, which is based on measuring the ratio of two luminescence images taken with two different spectral filters, is applicable, in principle, to both photoluminescence and electroluminescence measurements and is demonstrated experimentally by electroluminescence measurements on a multicrystalline silicon solar cell. Good agreement is observed with the diffusion length distribution obtained from a spectrally resolved light beam induced current map. In contrast to the determination of diffusion lengths from one single luminescence image, the method proposed heremore » gives absolute values of the diffusion length and, in comparison, it is much less sensitive to lateral voltage variations across the cell area as caused by local variations of the series resistance. It is also shown that measuring the ratio of two luminescence images allows distinguishing shunts or surface defects from bulk defects.« less

Relationship Between Physician Assistant Program Length and Physician Assistant National Certifying Examination Pass Rates.

PubMed

Colletti, Thomas P; Salisbury, Helen; Hertelendy, Attila J; Tseng, Tina

2016-03-01

This study was conducted to examine the relationship between physician assistant (PA) educational program length and PA programs' 5-year average Physician Assistant National Certifying Examination (PANCE) first-time pass rates. This was a retrospective correlational study that analyzed previously collected data from a nonprobability purposive sample of accredited PA program Web sites. Master's level PA programs (n = 108) in the United States with published average PANCE scores for 5 consecutive classes were included. Provisional and probationary programs were excluded (n = 4). Study data were not normally distributed per the Kolmogorov-Smirnov test, P = .00. There was no relationship between program length and PANCE pass rates, ρ (108) = -0.04, P = .68. Further analyses examining a possible relationship between program phase length (didactic and clinical) and PANCE pass rates also demonstrated no differences (ρ [107] = -0.05, P = .60 and ρ [107] = 0.02, P = .80, respectively). The results of this study suggest that shorter length PA programs perform similarly to longer programs in preparing students to pass the PANCE. In light of rapid expansion of PA educational programs, educators may want to consider these findings when planning the length of study for new and established programs.

Percentiles of the run-length distribution of the Exponentially Weighted Moving Average (EWMA) median chart

NASA Astrophysics Data System (ADS)

Tan, K. L.; Chong, Z. L.; Khoo, M. B. C.; Teoh, W. L.; Teh, S. Y.

2017-09-01

Quality control is crucial in a wide variety of fields, as it can help to satisfy customers’ needs and requirements by enhancing and improving the products and services to a superior quality level. The EWMA median chart was proposed as a useful alternative to the EWMA \\bar{X} chart because the median-type chart is robust against contamination, outliers or small deviation from the normality assumption compared to the traditional \\bar{X}-type chart. To provide a complete understanding of the run-length distribution, the percentiles of the run-length distribution should be investigated rather than depending solely on the average run length (ARL) performance measure. This is because interpretation depending on the ARL alone can be misleading, as the process mean shifts change according to the skewness and shape of the run-length distribution, varying from almost symmetric when the magnitude of the mean shift is large, to highly right-skewed when the process is in-control (IC) or slightly out-of-control (OOC). Before computing the percentiles of the run-length distribution, optimal parameters of the EWMA median chart will be obtained by minimizing the OOC ARL, while retaining the IC ARL at a desired value.

Testing the time-of-flight model for flagellar length sensing.

PubMed

Ishikawa, Hiroaki; Marshall, Wallace F

2017-11-07

Cilia and flagella are microtubule-based organelles that protrude from the surface of most cells, are important to the sensing of extracellular signals, and make a driving force for fluid flow. Maintenance of flagellar length requires an active transport process known as intraflagellar transport (IFT). Recent studies reveal that the amount of IFT injection negatively correlates with the length of flagella. These observations suggest that a length-dependent feedback regulates IFT. However, it is unknown how cells recognize the length of flagella and control IFT. Several theoretical models try to explain this feedback system. We focused on one of the models, the "time-of-flight" model, which measures the length of flagella on the basis of the travel time of IFT protein in the flagellar compartment. We tested the time-of-flight model using Chlamydomonas dynein mutant cells, which show slower retrograde transport speed. The amount of IFT injection in dynein mutant cells was higher than that in control cells. This observation does not support the prediction of the time-of-flight model and suggests that Chlamydomonas uses another length-control feedback system rather than that described by the time-of-flight model. © 2017 Ishikawa and Marshall. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Extracorporeal Circulation During Lung Transplantation Procedures: A Meta-Analysis.

PubMed

Hoechter, Dominik J; Shen, Yu-Ming; Kammerer, Tobias; Günther, Sabina; Weig, Thomas; Schramm, René; Hagl, Christian; Born, Frank; Meiser, Bruno; Preissler, Gerhard; Winter, Hauke; Czerner, Stephan; Zwissler, Bernhard; Mansmann, Ulrich U; von Dossow, Vera

Extracorporeal circulation (ECC) is an invaluable tool in lung transplantation (lutx). More than the past years, an increasing number of centers changed their standard for intraoperative ECC from cardiopulmonary bypass (CPB) to extracorporeal membrane oxygenation (ECMO) - with differing results. This meta-analysis reviews the existing evidence. An online literature research on Medline, Embase, and PubMed has been performed. Two persons independently judged the papers using the ACROBAT-NRSI tool of the Cochrane collaboration. Meta-analyses and meta-regressions were used to determine whether veno-arterial ECMO (VA-ECMO) resulted in better outcomes compared with CPB. Six papers - all observational studies without randomization - were included in the analysis. All were considered to have serious bias caused by heparinization as co-intervention. Forest plots showed a beneficial trend of ECMO regarding blood transfusions (packed red blood cells (RBCs) with an average mean difference of -0.46 units [95% CI = -3.72, 2.80], fresh-frozen plasma with an average mean difference of -0.65 units [95% CI = -1.56, 0.25], platelets with an average mean difference of -1.72 units [95% CI = -3.67, 0.23]). Duration of ventilator support with an average mean difference of -2.86 days [95% CI = -11.43, 5.71] and intensive care unit (ICU) length of stay with an average mean difference of -4.79 days [95% CI = -8.17, -1.41] were shorter in ECMO patients. Extracorporeal membrane oxygenation treatment tended to be superior regarding 3 month mortality (odds ratio = 0.46, 95% CI = 0.21-1.02) and 1 year mortality (odds ratio = 0.65, 95% CI = 0.37-1.13). However, only the ICU length of stay reached statistical significance. Meta-regression analyses showed that heterogeneity across studies (sex, year of ECMO implementation, and underlying disease) influenced differences. These data indicate a benefit of the intraoperative use of ECMO as compared with CPB during lung transplant procedures regarding short-term outcome (ICU stay). There was no statistically significant effect regarding blood transfusion needs or long-term outcome. The superiority of ECMO in lutx patients remains to be determined in larger multi-center randomized trials.

Preliminary ex vivo feasibility study on targeted cell surgery by high intensity focused ultrasound (HIFU).

PubMed

Wang, Zhi Biao; Wu, Junru; Fang, Liao Qiong; Wang, Hua; Li, Fa Qi; Tian, Yun Bo; Gong, Xiao Bo; Zhang, Hong; Zhang, Lian; Feng, Ruo

2011-04-01

High intensity focused ultrasound (HIFU) has become a new noninvasive surgical modality in medicine. A portion of tissue seated inside a patient's body may experience coagulative necrosis after a few seconds of insonification by high intensity focused ultrasound (US) generated by an extracorporeal focusing US transducer. The region of tissue affected by coagulative necrosis (CN) usually has an ellipsoidal shape when the thermal effect due to US absorption plays the dominant role. Its long and short axes are parallel and perpendicular to the US propagation direction respectively. It was shown by numerical computations using a nonlinear Gaussian beams model to describe the sound field in a focal zone and ex vivo experiments that the dimension of the short and long axes of the tissue which experiences CN can be as small as 50μm and 250μm respectively after one second exposure of US pulse (the spatial and pulse average acoustic power is on the order of tens of Watts and the local acoustic spatial and temporal pulse averaged intensity is on the order of 3×10(4)W/cm(2)) generated by a 1.6MHz HIFU transducer of 12cm diameter and 11cm geometric focal length (f-number=0.92). The concept of thermal dose of cumulative equivalent minutes was used to describe the possible tissue coagulative necrosis generated by HIFU. The numbers of cells which suffered CN were estimated to be on the order of 40. This result suggests that HIFU is able to interact with tens of cells at/near its focal zone while keeping the neighboring cells minimally affected, and thus the targeted cell surgery may be achievable. Copyright © 2010 Elsevier B.V. All rights reserved.

Accurate cytogenetic biodosimetry through automated dicentric chromosome curation and metaphase cell selection

PubMed Central

Wilkins, Ruth; Flegal, Farrah; Knoll, Joan H.M.; Rogan, Peter K.

2017-01-01

Accurate digital image analysis of abnormal microscopic structures relies on high quality images and on minimizing the rates of false positive (FP) and negative objects in images. Cytogenetic biodosimetry detects dicentric chromosomes (DCs) that arise from exposure to ionizing radiation, and determines radiation dose received based on DC frequency. Improvements in automated DC recognition increase the accuracy of dose estimates by reclassifying FP DCs as monocentric chromosomes or chromosome fragments. We also present image segmentation methods to rank high quality digital metaphase images and eliminate suboptimal metaphase cells. A set of chromosome morphology segmentation methods selectively filtered out FP DCs arising primarily from sister chromatid separation, chromosome fragmentation, and cellular debris. This reduced FPs by an average of 55% and was highly specific to these abnormal structures (≥97.7%) in three samples. Additional filters selectively removed images with incomplete, highly overlapped, or missing metaphase cells, or with poor overall chromosome morphologies that increased FP rates. Image selection is optimized and FP DCs are minimized by combining multiple feature based segmentation filters and a novel image sorting procedure based on the known distribution of chromosome lengths. Applying the same image segmentation filtering procedures to both calibration and test samples reduced the average dose estimation error from 0.4 Gy to <0.2 Gy, obviating the need to first manually review these images. This reliable and scalable solution enables batch processing for multiple samples of unknown dose, and meets current requirements for triage radiation biodosimetry of high quality metaphase cell preparations. PMID:29026522

Construction of a Full-Length Enriched cDNA Library and Preliminary Analysis of Expressed Sequence Tags from Bengal Tiger Panthera tigris tigris

PubMed Central

Liu, Changqing; Liu, Dan; Guo, Yu; Lu, Taofeng; Li, Xiangchen; Zhang, Minghai; Ma, Jianzhang; Ma, Yuehui; Guan, Weijun

2013-01-01

In this study, a full-length enriched cDNA library was successfully constructed from Bengal tiger, Panthera tigris tigris, the most well-known wild Animal. Total RNA was extracted from cultured Bengal tiger fibroblasts in vitro. The titers of primary and amplified libraries were 1.28 × 106 pfu/mL and 1.56 × 109 pfu/mL respectively. The percentage of recombinants from unamplified library was 90.2% and average length of exogenous inserts was 0.98 kb. A total of 212 individual ESTs with sizes ranging from 356 to 1108 bps were then analyzed. The BLASTX score revealed that 48.1% of the sequences were classified as a strong match, 45.3% as nominal and 6.6% as a weak match. Among the ESTs with known putative function, 26.4% ESTs were found to be related to all kinds of metabolisms, 19.3% ESTs to information storage and processing, 11.3% ESTs to posttranslational modification, protein turnover, chaperones, 11.3% ESTs to transport, 9.9% ESTs to signal transducer/cell communication, 9.0% ESTs to structure protein, 3.8% ESTs to cell cycle, and only 6.6% ESTs classified as novel genes. By EST sequencing, a full-length gene coding ferritin was identified and characterized. The recombinant plasmid pET32a-TAT-Ferritin was constructed, coded for the TAT-Ferritin fusion protein with two 6× His-tags in N and C-terminal. After BCA assay, the concentration of soluble Trx-TAT-Ferritin recombinant protein was 2.32 ± 0.12 mg/mL. These results demonstrated that the reliability and representativeness of the cDNA library attained to the requirements of a standard cDNA library. This library provided a useful platform for the functional genome and transcriptome research of Bengal tigers. PMID:23708105

Construction of a full-length enriched cDNA library and preliminary analysis of expressed sequence tags from Bengal Tiger Panthera tigris tigris.

PubMed

Liu, Changqing; Liu, Dan; Guo, Yu; Lu, Taofeng; Li, Xiangchen; Zhang, Minghai; Ma, Jianzhang; Ma, Yuehui; Guan, Weijun

2013-05-24

In this study, a full-length enriched cDNA library was successfully constructed from Bengal tiger, Panthera tigris tigris, the most well-known wild Animal. Total RNA was extracted from cultured Bengal tiger fibroblasts in vitro. The titers of primary and amplified libraries were 1.28 × 106 pfu/mL and 1.56 × 109 pfu/mL respectively. The percentage of recombinants from unamplified library was 90.2% and average length of exogenous inserts was 0.98 kb. A total of 212 individual ESTs with sizes ranging from 356 to 1108 bps were then analyzed. The BLASTX score revealed that 48.1% of the sequences were classified as a strong match, 45.3% as nominal and 6.6% as a weak match. Among the ESTs with known putative function, 26.4% ESTs were found to be related to all kinds of metabolisms, 19.3% ESTs to information storage and processing, 11.3% ESTs to posttranslational modification, protein turnover, chaperones, 11.3% ESTs to transport, 9.9% ESTs to signal transducer/cell communication, 9.0% ESTs to structure protein, 3.8% ESTs to cell cycle, and only 6.6% ESTs classified as novel genes. By EST sequencing, a full-length gene coding ferritin was identified and characterized. The recombinant plasmid pET32a-TAT-Ferritin was constructed, coded for the TAT-Ferritin fusion protein with two 6× His-tags in N and C-terminal. After BCA assay, the concentration of soluble Trx-TAT-Ferritin recombinant protein was 2.32 ± 0.12 mg/mL. These results demonstrated that the reliability and representativeness of the cDNA library attained to the requirements of a standard cDNA library. This library provided a useful platform for the functional genome and transcriptome research of Bengal tigers.

Accuracy of acoustic velocity metering systems for measurement of low velocity in open channels

USGS Publications Warehouse

Laenen, Antonius; Curtis, R. E.

1989-01-01

Acoustic velocity meter (AVM) accuracy depends on equipment limitations, the accuracy of acoustic-path length and angle determination, and the stability of the mean velocity to acoustic-path velocity relation. Equipment limitations depend on path length and angle, transducer frequency, timing oscillator frequency, and signal-detection scheme. Typically, the velocity error from this source is about +or-1 to +or-10 mms/sec. Error in acoustic-path angle or length will result in a proportional measurement bias. Typically, an angle error of one degree will result in a velocity error of 2%, and a path-length error of one meter in 100 meter will result in an error of 1%. Ray bending (signal refraction) depends on path length and density gradients present in the stream. Any deviation from a straight acoustic path between transducer will change the unique relation between path velocity and mean velocity. These deviations will then introduce error in the mean velocity computation. Typically, for a 200-meter path length, the resultant error is less than one percent, but for a 1,000 meter path length, the error can be greater than 10%. Recent laboratory and field tests have substantiated assumptions of equipment limitations. Tow-tank tests of an AVM system with a 4.69-meter path length yielded an average standard deviation error of 9.3 mms/sec, and the field tests of an AVM system with a 20.5-meter path length yielded an average standard deviation error of a 4 mms/sec. (USGS)

Prostate stromal cell telomere shortening is associated with risk of prostate cancer in the placebo arm of the Prostate Cancer Prevention Trial*

PubMed Central

Heaphy, Christopher M.; Gaonkar, Gaurav; Peskoe, Sarah B.; Joshu, Corinne E.; De Marzo, Angelo M.; Lucia, M. Scott; Goodman, Phyllis J.; Lippman, Scott M.; Thompson, Ian M.; Platz, Elizabeth A.; Meeker, Alan K.

2015-01-01

Background Telomeres are repetitive nucleoproteins that help maintain chromosomal stability by inhibiting exonucleolytic degradation, prohibiting inappropriate homologous recombination, and preventing chromosomal fusions by suppressing double-strand break signals. We recently observed that men treated for clinically localized prostate cancer with shorter telomeres in their cancer-associated stromal cells, in combination with greater variation in cancer cell telomere lengths, were significantly more likely to progress to distant metastases and die from their disease. Here, we hypothesized that shorter stromal cell telomere length would be associated with prostate cancer risk at time of biopsy. Methods Telomere-specific fluorescence in situ hybridization (FISH) analysis was performed in normal-appearing stromal, basal epithelial, and luminal epithelial cells in biopsies from men randomized to the placebo arm of the Prostate Cancer Prevention Trial. Prostate cancer cases (N=32) were either detected on a biopsy performed for cause or at the end of the study per trial protocol, and controls (N=50), defined as negative for cancer on an end-of-study biopsy performed per trial protocol (e.g. irrespective of indication), were sampled. Logistic regression was used to estimate the association between mean telomere length of the particular cell populations, cell-to-cell telomere length variability, and risk of prostate cancer. Results Men with short stromal cell telomere lengths (below median) had 2.66 (95% CI 1.04-3.06; p=0.04) times the odds of prostate cancer compared with men who had longer lengths (at or above median). Conversely, we did not observe statistically significant associations for short telomere lengths in normal-appearing basal (OR=2.15, 95% CI 0.86-5.39; p=0.10) or luminal (OR=1.15, 95% CI 0.47-2.80; p=0.77) cells. Conclusions These findings suggest that telomere shortening in normal stromal cells is associated with prostate cancer risk. It is essential to extend and validate these findings, while also identifying the cellular milieu that comprises the subset of cells with short telomeres within the prostate tumor microenvironment. PMID:25893825

Prostate stromal cell telomere shortening is associated with risk of prostate cancer in the placebo arm of the Prostate Cancer Prevention Trial.

PubMed

Heaphy, Christopher M; Gaonkar, Gaurav; Peskoe, Sarah B; Joshu, Corinne E; De Marzo, Angelo M; Lucia, M Scott; Goodman, Phyllis J; Lippman, Scott M; Thompson, Ian M; Platz, Elizabeth A; Meeker, Alan K

2015-08-01

Telomeres are repetitive nucleoproteins that help maintain chromosomal stability by inhibiting exonucleolytic degradation, prohibiting inappropriate homologous recombination, and preventing chromosomal fusions by suppressing double-strand break signals. We recently observed that men treated for clinically localized prostate cancer with shorter telomeres in their cancer-associated stromal cells, in combination with greater variation in cancer cell telomere lengths, were significantly more likely to progress to distant metastases, and die from their disease. Here, we hypothesized that shorter stromal cell telomere length would be associated with prostate cancer risk at time of biopsy. Telomere-specific fluorescence in situ hybridization (FISH) analysis was performed in normal-appearing stromal, basal epithelial, and luminal epithelial cells in biopsies from men randomized to the placebo arm of the Prostate Cancer Prevention Trial. Prostate cancer cases (N = 32) were either detected on a biopsy performed for cause or at the end of the study per trial protocol, and controls (N = 50), defined as negative for cancer on an end-of-study biopsy performed per trial protocol (e.g., irrespective of indication), were sampled. Logistic regression was used to estimate the association between mean telomere length of the particular cell populations, cell-to-cell telomere length variability, and risk of prostate cancer. Men with short stromal cell telomere lengths (below median) had 2.66 (95% CI 1.04-3.06; P = 0.04) times the odds of prostate cancer compared with men who had longer lengths (at or above median). Conversely, we did not observe statistically significant associations for short telomere lengths in normal-appearing basal (OR = 2.15, 95% CI 0.86-5.39; P= 0 .10) or luminal (OR = 1.15, 95% CI 0.47-2.80; P = 0.77) cells. These findings suggest that telomere shortening in normal stromal cells is associated with prostate cancer risk. It is essential to extend and validate these findings, while also identifying the cellular milieu that comprises the subset of cells with short telomeres within the prostate tumor microenvironment. © 2015 Wiley Periodicals, Inc.

High-resolution telomere fluorescence in situ hybridization reveals intriguing anomalies in germ cell tumors.

PubMed

Shekhani, Mohammed Talha; Barber, John R; Bezerra, Stephania M; Heaphy, Christopher M; Gonzalez Roibon, Nilda Diana; Taheri, Diana; Reis, Leonardo O; Guner, Gunes; Joshu, Corinne E; Netto, George J; Meeker, Alan K

2016-08-01

Testicular germ cell tumor (TGCT) is the most common malignancy of young men. Most patients are completely cured, which distinguishes these from most other malignancies. Orchiectomy specimens (n=76) were evaluated using high-resolution (single-cell discriminative) telomere-specific fluorescence in situ hybridization (FISH) with simultaneous Oct4 immunofluorescence to describe telomere length phenotype in TGCT neoplastic cells. For the first time, the TGCT precursor lesion, germ cell neoplasia in situ (GCNIS) is also evaluated in depth. The intensity of the signals from cancerous cells was compared to the same patient's reference cells-namely, healthy germ cells (defined as "medium" length) and interstitial/somatic cells (defined as "short" telomere length). We observed short telomeres in most GCNIS and pure seminomas (P=.006 and P=.0005, respectively). In contrast, nonseminomas displayed longer telomeres. Lesion-specific telomere lengths were documented in mixed tumor cases. Embryonal carcinoma (EC) demonstrated the longest telomeres. A fraction of EC displays the telomerase-independent alternative lengthening of telomeres (ALT) phenotype (24% of cases). Loss of ATRX or DAXX nuclear expression was strongly associated with ALT; however, nuclear expression of both proteins was retained in half of ALT-positive ECs. The particular distribution of telomere lengths among TGCT and GCNIS precursors implicate telomeres anomalies in pathogenesis. These results may advise management decisions as well. Copyright © 2016. Published by Elsevier Inc.

Optical mapping of prefrontal brain connectivity and activation during emotion anticipation.

PubMed

Wang, Meng-Yun; Lu, Feng-Mei; Hu, Zhishan; Zhang, Juan; Yuan, Zhen

2018-09-17

Accumulated neuroimaging evidence shows that the dorsal lateral prefrontal cortex (dlPFC) is activated during emotion anticipation. The aim of this work is to examine the brain connectivity and activation differences in dlPFC between the positive, neutral and negative emotion anticipation by using functional near-infrared spectroscopy (fNIRS). The hemodynamic responses were first assessed for all subjects during the performance of various emotion anticipation tasks. And then small-world analysis was performed, in which the small-world network indicators including the clustering coefficient, average path length, average node degree, and measure of small-world index were calculated for the functional brain networks associated with the positive, neutral and negative emotion anticipation, respectively. We discovered that compared to negative and neutral emotion anticipation, the positive one exhibited enhanced brain activation in the left dlPFC. Although the functional brain networks for the three emotion anticipation cases manifested the small-world properties regarding the clustering coefficient, average path length, average node degree, and measure of small-world index, the positive one showed significantly higher clustering coefficient and shorter average path length than those from the neutral and negative cases. Consequently, the small-world network indicators and brain activation in dlPPC were able to distinguish well between the positive, neutral and negative emotion anticipation. Copyright © 2018 Elsevier B.V. All rights reserved.

Estimating the Length of the North Atlantic Basin Hurricane Season

NASA Technical Reports Server (NTRS)

Wilson, Robert M.

2012-01-01

For the interval 1945-2011, the length of the hurricane season in the North Atlantic basin averages about 130 +/- 42 days (the +/-1 standard deviation interval), having a range of 47 to 235 days. Runs-testing reveals that the annual length of season varies nonrandomly at the 5% level of significance. In particular, its trend, as described using 10-yr moving averages, generally has been upward since about 1979, increasing from about 113 to 157 days (in 2003). Based on annual values, one finds a highly statistically important inverse correlation at the 0.1% level of significance between the length of season and the occurrence of the first storm day of the season. For the 2012 hurricane season, based on the reported first storm day of May 19, 2012 (i.e., DOY = 140), the inferred preferential regression predicts that the length of the current season likely will be about 173 +/- 23 days, suggesting that it will end about November 8 +/- 23 days, with only about a 5% chance that it will end either before about September 23, 2012 or after about December 24, 2012.

Anomalous behaviors during infiltration into heterogeneous porous media

NASA Astrophysics Data System (ADS)

Aarão Reis, F. D. A.; Bolster, D.; Voller, V. R.

2018-03-01

Flow and transport in heterogeneous porous media often exhibit anomalous behavior. A physical analog example is the uni-directional infiltration of a viscous liquid into a horizontal oriented Hele-Shaw cell containing through thickness flow obstacles; a system designed to mimic a gravel/sand medium with impervious inclusions. When there are no obstacles present or the obstacles form a multi-repeating pattern, the change of the length of infiltration F with time t tends to follow a Fickian like scaling, F ∼t1/2 . In the presence of obstacle fields laid out as Sierpinski carpet fractals, infiltration is anomalous, i.e., F ∼ tn, n ≠ 1/2. Here, we study infiltration into such Hele-Shaw cells. First we investigate infiltration into a square cell containing one fractal carpet and make the observation that it is possible to generate both sub (n < 1/2) and super (n > 1/2) diffusive behaviors within identical heterogeneity configurations. We show that this can be explained in terms of a scaling analysis developed from results of random-walk simulations in fractal obstacles; a result indicating that the nature of the domain boundary controls the exponent n of the resulting anomalous transport. Further, we investigate infiltration into a rectangular cell containing several repeats of a given Sierpinski carpet. At very early times, before the liquid encounters any obstacles, the infiltration is Fickian. When the liquid encounters the first (smallest scale) obstacle the infiltration sharply transitions to sub-diffusive. Subsequently, around the time where the liquid has sampled all of the heterogeneity length scales in the system, there is a rapid transition back to Fickian behavior. An explanation for this second transition is obtained by developing a simplified infiltration model based on the definition of a representative averaged hydraulic conductivity.

Simple shearing flow of dry soap foams with tetrahedrally close-packed structure

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

Reinelt, Douglas A.; Kraynik, Andrew M.

2000-05-01

The microrheology of dry soap foams subjected to quasistatic, simple shearing flow is analyzed. Two different monodisperse foams with tetrahedrally close-packed (TCP) structure are examined: Weaire-Phelan (A15) and Friauf-Laves (C15). The elastic-plastic response is evaluated by using the Surface Evolver to calculate foam structures that minimize total surface area at each value of strain. The foam geometry and macroscopic stress are piecewise continuous functions of strain. The stress scales as T/V{sup 1/3}, where T is surface tension and V is cell volume. Each discontinuity corresponds to large changes in foam geometry and topology that restore equilibrium to unstable configurations thatmore » violate Plateau's laws. The instabilities occur when the length of an edge on a polyhedral foam cell vanishes. The length can tend to zero smoothly or abruptly with strain. The abrupt case occurs when a small increase in strain changes the energy profile in the neighborhood of a foam structure from a local minimum to a saddle point, which can lead to symmetry-breaking bifurcations. In general, the new structure associated with each stable solution branch results from an avalanche of local topology changes called T1 transitions. Each T1 cascade produces different cell neighbors, reduces surface energy, and provides an irreversible, film-level mechanism for plastic yield behavior. Stress-strain curves and average stresses are evaluated by examining foam orientations that admit strain-periodic behavior. For some orientations, the deformation cycle includes Kelvin cells instead of the original TCP structure; but the foam does not remain perfectly ordered. Bifurcations during subsequent T1 cascades lead to disorder and can even cause strain localization. (c) 2000 Society of Rheology.« less

Simple shearing flow of dry soap foams with TCP structure[Tetrahedrally Close-Packed

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

REINELT,DOUGLAS A.; KRAYNIK,ANDREW M.

2000-02-16

The microrheology of dry soap foams subjected to large, quasistatic, simple shearing deformations is analyzed. Two different monodisperse foams with tetrahedrally close-packed (TCP) structure are examined: Weaire-Phelan (A15) and Friauf-Laves (C15). The elastic-plastic response is evaluated by calculating foam structures that minimize total surface area at each value of strain. The minimal surfaces are computed with the Surface Evolver program developed by Brakke. The foam geometry and macroscopic stress are piecewise continuous functions of strain. The stress scales as T/V{sup 1/3} where T is surface tension and V is cell volume. Each discontinuity corresponds to large changes in foam geometrymore » and topology that restore equilibrium to unstable configurations that violate Plateau's laws. The instabilities occur when the length of an edge on a polyhedral foam cell vanishes. The length can tend to zero smoothly or abruptly with strain. The abrupt case occurs when a small increase in strain changes the energy profile in the neighborhood of a foam structure from a local minimum to a saddle point, which can lead to symmetry-breaking bifurcations. In general, the new foam topology associated with each stable solution branch results from a cascade of local topology changes called T1 transitions. Each T1 cascade produces different cell neighbors, reduces surface energy, and provides an irreversible, film-level mechanism for plastic yield behavior. Stress-strain curves and average stresses are evaluated by examining foam orientations that admit strain-periodic behavior. For some orientations, the deformation cycle includes Kelvin cells instead of the original TCP structure; but the foam does not remain perfectly ordered. Bifurcations during subsequent T1 cascades lead to disorder and can even cause strain localization.« less

Phagosomal pH and glass fiber dissolution in cultured nasal epithelial cells and alveolar macrophages: a preliminary study.

PubMed Central

Johnson, N F

1994-01-01

The dissolution rate of glass fibers has been shown to be pH sensitive using in vitro lung fluid simulant models. The current study investigated whether there is a difference in phagosomal pH (ppH) between rat alveolar macrophages (AM) and rat nasal epithelial cells (RNEC) and whether such a difference would influence the dissolution of glass fibers. The ppH was measured in cultured AM and RNEC using flow cytometric, fluorescence-emission rationing techniques with fluorescein-labeled, amorphous silica particles. Glass fiber dissolution was determined in AM and RNEC cultured for 3 weeks with fast dissolving glass fibers (GF-A) or slow dissolving ones (GF-B). The mean diameters of GF-A were 2.7 microns and of GF-B, 2.6 microns, the average length of both fibers was approximately 22 to 25 microns. Dissolution was monitored by measuring the length and diameter of intracellular fibers and estimating the volume, assuming a cylindrical morphology. The ppH of AM was 5.2 to 5.8, and the ppH of RNEC was 7.0 to 7.5. The GF-A dissolved more slowly in RNEC than in AM, and no dissolution was evident in either cell type with GF-B. The volume loss with GF-A after a 3-week culture with AM was 66% compared to 45% for cultured RNEC. These results are different from those obtained using in vitro lung fluid-simulant models where dissolution is faster at higher pH. This difference suggests that dissolution rates of glass fibers in AM should not be applied to the dissolution of fibers in epithelial cells. Images Figure 1. a Figure 1. b Figure 2. a Figure 2. b Figure 3. a Figure 3. b PMID:7882965

An interplanetary magnetic field ensemble at 1 AU

NASA Technical Reports Server (NTRS)

Matthaeus, W. H.; Goldstein, M. L.; King, J. H.

1985-01-01

A method for calculation ensemble averages from magnetic field data is described. A data set comprising approximately 16 months of nearly continuous ISEE-3 magnetic field data is used in this study. Individual subintervals of this data, ranging from 15 hours to 15.6 days comprise the ensemble. The sole condition for including each subinterval in the averages is the degree to which it represents a weakly time-stationary process. Averages obtained by this method are appropriate for a turbulence description of the interplanetary medium. The ensemble average correlation length obtained from all subintervals is found to be 4.9 x 10 to the 11th cm. The average value of the variances of the magnetic field components are in the approximate ratio 8:9:10, where the third component is the local mean field direction. The correlation lengths and variances are found to have a systematic variation with subinterval duration, reflecting the important role of low-frequency fluctuations in the interplanetary medium.

Inorganic polyphosphate in the yeast Saccharomyces cerevisiae with a mutation disturbing the function of vacuolar ATPase.

PubMed

Tomaschevsky, A A; Ryasanova, L P; Kulakovskaya, T V; Kulaev, I S

2010-08-01

A mutation in the vma2 gene disturbing V-ATPase function in the yeast Saccharomyces cerevisiae results in a five- and threefold decrease in inorganic polyphosphate content in the stationary and active phases of growth on glucose, respectively. The average polyphosphate chain length in the mutant cells is decreased. The mutation does not prevent polyphosphate utilization during cultivation in a phosphate-deficient medium and recovery of its level on reinoculation in complete medium after phosphate deficiency. The content of short chain acid-soluble polyphosphates is recovered first. It is supposed that these polyphosphates are less dependent on the electrochemical gradient on the vacuolar membrane.

Telomete length in peripheral blood mononuclear cells is associated with folate status in men

USDA-ARS?s Scientific Manuscript database

Human chromosomes are capped by tandem repeats of DNA and associated proteins termed telomeres. The length of the telomeres is reduced with increasing cell divisions except when the enzyme telomerase is active as seen in stem cells and germ cells. Telomere dysfunction has been associated with deve...

Quantitative study of Xanthosoma violaceum leaf surfaces using RIMAPS and variogram techniques.

PubMed

Favret, Eduardo A; Fuentes, Néstor O; Molina, Ana M

2006-08-01

Two new imaging techniques (rotated image with maximum averaged power spectrum (RIMAPS) and variogram) are presented for the study and description of leaf surfaces. Xanthosoma violaceum was analyzed to illustrate the characteristics of both techniques. Both techniques produce a quantitative description of leaf surface topography. RIMAPS combines digitized images rotation with Fourier transform, and it is used to detect patterns orientation and characteristics of surface topography. Variogram relates the mathematical variance of a surface with the area of the sample window observed. It gives the typical scale lengths of the surface patterns. RIMAPS detects the morphological variations of the surface topography pattern between fresh and dried (herbarium) samples of the leaf. The variogram method finds the characteristic dimensions of the leaf microstructure, i.e., cell length, papillae diameter, etc., showing that there are not significant differences between dry and fresh samples. The results obtained show the robustness of RIMAPS and variogram analyses to detect, distinguish, and characterize leaf surfaces, as well as give scale lengths. Both techniques are tools for the biologist to study variations of the leaf surface when different patterns are present. The use of RIMAPS and variogram opens a wide spectrum of possibilities by providing a systematic, quantitative description of the leaf surface topography.

Single-cell full-length total RNA sequencing uncovers dynamics of recursive splicing and enhancer RNAs.

PubMed

Hayashi, Tetsutaro; Ozaki, Haruka; Sasagawa, Yohei; Umeda, Mana; Danno, Hiroki; Nikaido, Itoshi

2018-02-12

Total RNA sequencing has been used to reveal poly(A) and non-poly(A) RNA expression, RNA processing and enhancer activity. To date, no method for full-length total RNA sequencing of single cells has been developed despite the potential of this technology for single-cell biology. Here we describe random displacement amplification sequencing (RamDA-seq), the first full-length total RNA-sequencing method for single cells. Compared with other methods, RamDA-seq shows high sensitivity to non-poly(A) RNA and near-complete full-length transcript coverage. Using RamDA-seq with differentiation time course samples of mouse embryonic stem cells, we reveal hundreds of dynamically regulated non-poly(A) transcripts, including histone transcripts and long noncoding RNA Neat1. Moreover, RamDA-seq profiles recursive splicing in >300-kb introns. RamDA-seq also detects enhancer RNAs and their cell type-specific activity in single cells. Taken together, we demonstrate that RamDA-seq could help investigate the dynamics of gene expression, RNA-processing events and transcriptional regulation in single cells.

Single Stem Cell Imaging and Analysis Reveals Telomere Length Differences in Diseased Human and Mouse Skeletal Muscles.

PubMed

Tichy, Elisia D; Sidibe, David K; Tierney, Matthew T; Stec, Michael J; Sharifi-Sanjani, Maryam; Hosalkar, Harish; Mubarak, Scott; Johnson, F Brad; Sacco, Alessandra; Mourkioti, Foteini

2017-10-10

Muscle stem cells (MuSCs) contribute to muscle regeneration following injury. In many muscle disorders, the repeated cycles of damage and repair lead to stem cell dysfunction. While telomere attrition may contribute to aberrant stem cell functions, methods to accurately measure telomere length in stem cells from skeletal muscles have not been demonstrated. Here, we have optimized and validated such a method, named MuQ-FISH, for analyzing telomere length in MuSCs from either mice or humans. Our analysis showed no differences in telomere length between young and aged MuSCs from uninjured wild-type mice, but MuSCs isolated from young dystrophic mice exhibited significantly shortened telomeres. In corroboration, we demonstrated that telomere attrition is present in human dystrophic MuSCs, which underscores its importance in diseased regenerative failure. The robust technique described herein provides analysis at a single-cell resolution and may be utilized for other cell types, especially rare populations of cells. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Dorsal Phalloplasty to Preserve Penis Length after Penile Prosthesis Implantation

PubMed Central

Shaeer, Osama; Shaeer, Kamal; Rahman, Islam A.

2017-01-01

Objectives Following penile prosthesis implantation (PPI), patients may complain of a decrease in visible penis length. A dorsal phalloplasty defines the penopubic junction by tacking pubic skin to the pubis, revealing the base of the penis. This study aimed to evaluate the efficacy of a dorsal phalloplasty in increasing the visible penis length following PPI. Methods An inflatable penile prosthesis was implanted in 13 patients with severe erectile dysfunction (ED) at the Kamal Shaeer Hospital, Cairo, Egypt, from January 2013 to May 2014. During the surgery, nonabsorbable tacking sutures were used to pin the pubic skin to the pubis through the same penoscrotal incision. Intraoperative penis length was measured before and after the dorsal phalloplasty. Overall patient satisfaction was measured on a 5-point rating scale and patients were requested to subjectively compare their postoperative penis length with memories of their penis length before the onset of ED. Results Intraoperatively, the dorsal phalloplasty increased the visible length of the erect penis by an average of 25.6%. The average length before and after tacking was 10.2 ± 2.9 cm and 13.7 ± 2.8 cm, respectively (P <0.002). Postoperatively, seven patients (53.8%) reported a longer penis, five patients (38.5%) reported no change in length and one patient (7.7%) reported a slightly shorter penis. The mean overall patient satisfaction score was 4.9 ± 0.3. None of the patients developed postoperative complications. Conclusion A dorsal phalloplasty during PPI is an effective method of increasing visible penis length, therefore minimising the impression of a shorter penis after implantation. PMID:28417025

Fiber optic sensing system

NASA Technical Reports Server (NTRS)

Adamovsky, Grigory (Inventor)

1991-01-01

A fiber optic interferometer utilizes a low coherence light emitting diode (LED) laser as a light source which is filtered and driven at two RF frequencies, high and low, that are specific to the initial length of the resonator chamber. A displacement of a reflecting mirror changes the length traveled by the nonreferencing signal. The low frequency light undergoes destructive interference which reduces the average intensity of the wave while the high frequency light undergoes constructive interference which increases the average intensity of the wave. The ratio of these two intensity measurements is proportional to the displacement incurred.

Reducing the length of hospital stay after total knee arthroplasty: influence of femoral and sciatic nerve block.

PubMed

Carvalho Júnior, Lúcio Honório de; Temponi, Eduardo Frois; Paganini, Vinícius Oliveira; Costa, Lincoln Paiva; Soares, Luiz Fernando Machado; Gonçalves, Matheus Braga Jacques

2015-01-01

the aim of this study is to evaluate the change in length of hospital stay postoperatively for Total Knee Arthroplasty after using femoral and sciatic nerve block. the medical records of 287 patients were evaluated, taking into account the number of hours of admission, the percentage and the reason for re-hospitalization within 30 days, as well as associated complications. All patients were divided into two groups according or not to whether they were admitted to ICU or not. During the years 2009 and 2010, isolated spinal anesthesia was the method used in the procedure. From 2011 on, femoral and sciatic nerve blocking was introduced. between the years 2009 and 2012, the average length of stay ranged from 74 hours in 2009 to 75.2 hours in 2010. The average length of stay in 2011 was 56.52 hours and 53.72 hours in 2012, all in the group of patients who did not remain in the ICU postoperatively. In the same period, among those in the group that needed ICU admission, the average length of stay was 138.7 hours in 2009, 90.25 hours in 2010, 79.8 hours in 2011, and 52.91 hours in 2012. During 2009 and 2010, the rate of re-hospitalization was 0%, while in 2011 and 2012, were 3.44% and 1%, respectively. according to this study, the use of femoral and sciatic nerve blocking after total knee arthroplasty allowed significant reduction in hospital stay.

Genetic Variants Related to Longer Telomere Length are Associated with Increased Risk of Renal Cell Carcinoma.

PubMed

Machiela, Mitchell J; Hofmann, Jonathan N; Carreras-Torres, Robert; Brown, Kevin M; Johansson, Mattias; Wang, Zhaoming; Foll, Matthieu; Li, Peng; Rothman, Nathaniel; Savage, Sharon A; Gaborieau, Valerie; McKay, James D; Ye, Yuanqing; Henrion, Marc; Bruinsma, Fiona; Jordan, Susan; Severi, Gianluca; Hveem, Kristian; Vatten, Lars J; Fletcher, Tony; Koppova, Kvetoslava; Larsson, Susanna C; Wolk, Alicja; Banks, Rosamonde E; Selby, Peter J; Easton, Douglas F; Pharoah, Paul; Andreotti, Gabriella; Freeman, Laura E Beane; Koutros, Stella; Albanes, Demetrius; Mannisto, Satu; Weinstein, Stephanie; Clark, Peter E; Edwards, Todd E; Lipworth, Loren; Gapstur, Susan M; Stevens, Victoria L; Carol, Hallie; Freedman, Matthew L; Pomerantz, Mark M; Cho, Eunyoung; Kraft, Peter; Preston, Mark A; Wilson, Kathryn M; Gaziano, J Michael; Sesso, Howard S; Black, Amanda; Freedman, Neal D; Huang, Wen-Yi; Anema, John G; Kahnoski, Richard J; Lane, Brian R; Noyes, Sabrina L; Petillo, David; Colli, Leandro M; Sampson, Joshua N; Besse, Celine; Blanche, Helene; Boland, Anne; Burdette, Laurie; Prokhortchouk, Egor; Skryabin, Konstantin G; Yeager, Meredith; Mijuskovic, Mirjana; Ognjanovic, Miodrag; Foretova, Lenka; Holcatova, Ivana; Janout, Vladimir; Mates, Dana; Mukeriya, Anush; Rascu, Stefan; Zaridze, David; Bencko, Vladimir; Cybulski, Cezary; Fabianova, Eleonora; Jinga, Viorel; Lissowska, Jolanta; Lubinski, Jan; Navratilova, Marie; Rudnai, Peter; Szeszenia-Dabrowska, Neonila; Benhamou, Simone; Cancel-Tassin, Geraldine; Cussenot, Olivier; Bueno-de-Mesquita, H Bas; Canzian, Federico; Duell, Eric J; Ljungberg, Börje; Sitaram, Raviprakash T; Peters, Ulrike; White, Emily; Anderson, Garnet L; Johnson, Lisa; Luo, Juhua; Buring, Julie; Lee, I-Min; Chow, Wong-Ho; Moore, Lee E; Wood, Christopher; Eisen, Timothy; Larkin, James; Choueiri, Toni K; Lathrop, G Mark; Teh, Bin Tean; Deleuze, Jean-Francois; Wu, Xifeng; Houlston, Richard S; Brennan, Paul; Chanock, Stephen J; Scelo, Ghislaine; Purdue, Mark P

2017-11-01

Relative telomere length in peripheral blood leukocytes has been evaluated as a potential biomarker for renal cell carcinoma (RCC) risk in several studies, with conflicting findings. We performed an analysis of genetic variants associated with leukocyte telomere length to assess the relationship between telomere length and RCC risk using Mendelian randomization, an approach unaffected by biases from temporal variability and reverse causation that might have affected earlier investigations. Genotypes from nine telomere length-associated variants for 10 784 cases and 20 406 cancer-free controls from six genome-wide association studies (GWAS) of RCC were aggregated into a weighted genetic risk score (GRS) predictive of leukocyte telomere length. Odds ratios (ORs) relating the GRS and RCC risk were computed in individual GWAS datasets and combined by meta-analysis. Longer genetically inferred telomere length was associated with an increased risk of RCC (OR=2.07 per predicted kilobase increase, 95% confidence interval [CI]:=1.70-2.53, p<0.0001). As a sensitivity analysis, we excluded two telomere length variants in linkage disequilibrium (R 2 >0.5) with GWAS-identified RCC risk variants (rs10936599 and rs9420907) from the telomere length GRS; despite this exclusion, a statistically significant association between the GRS and RCC risk persisted (OR=1.73, 95% CI=1.36-2.21, p<0.0001). Exploratory analyses for individual histologic subtypes suggested comparable associations with the telomere length GRS for clear cell (N=5573, OR=1.93, 95% CI=1.50-2.49, p<0.0001), papillary (N=573, OR=1.96, 95% CI=1.01-3.81, p=0.046), and chromophobe RCC (N=203, OR=2.37, 95% CI=0.78-7.17, p=0.13). Our investigation adds to the growing body of evidence indicating some aspect of longer telomere length is important for RCC risk. Telomeres are segments of DNA at chromosome ends that maintain chromosomal stability. Our study investigated the relationship between genetic variants associated with telomere length and renal cell carcinoma risk. We found evidence suggesting individuals with inherited predisposition to longer telomere length are at increased risk of developing renal cell carcinoma. Published by Elsevier B.V.

Relationship research between meteorological disasters and stock markets based on a multifractal detrending moving average algorithm

NASA Astrophysics Data System (ADS)

Li, Qingchen; Cao, Guangxi; Xu, Wei

2018-01-01

Based on a multifractal detrending moving average algorithm (MFDMA), this study uses the fractionally autoregressive integrated moving average process (ARFIMA) to demonstrate the effectiveness of MFDMA in the detection of auto-correlation at different sample lengths and to simulate some artificial time series with the same length as the actual sample interval. We analyze the effect of predictable and unpredictable meteorological disasters on the US and Chinese stock markets and the degree of long memory in different sectors. Furthermore, we conduct a preliminary investigation to determine whether the fluctuations of financial markets caused by meteorological disasters are derived from the normal evolution of the financial system itself or not. We also propose several reasonable recommendations.

The Length Distribution of Class I-Restricted T Cell Epitopes Is Determined by Both Peptide Supply and MHC Allele-Specific Binding Preference.

PubMed

Trolle, Thomas; McMurtrey, Curtis P; Sidney, John; Bardet, Wilfried; Osborn, Sean C; Kaever, Thomas; Sette, Alessandro; Hildebrand, William H; Nielsen, Morten; Peters, Bjoern

2016-02-15

HLA class I-binding predictions are widely used to identify candidate peptide targets of human CD8(+) T cell responses. Many such approaches focus exclusively on a limited range of peptide lengths, typically 9 aa and sometimes 9-10 aa, despite multiple examples of dominant epitopes of other lengths. In this study, we examined whether epitope predictions can be improved by incorporating the natural length distribution of HLA class I ligands. We found that, although different HLA alleles have diverse length-binding preferences, the length profiles of ligands that are naturally presented by these alleles are much more homogeneous. We hypothesized that this is due to a defined length profile of peptides available for HLA binding in the endoplasmic reticulum. Based on this, we created a model of HLA allele-specific ligand length profiles and demonstrate how this model, in combination with HLA-binding predictions, greatly improves comprehensive identification of CD8(+) T cell epitopes. Copyright © 2016 by The American Association of Immunologists, Inc.

Treatment of odontogenic infections: An analysis of two antibiotic regimens.

PubMed

Bhagania, Manish; Youseff, Wael; Mehra, Pushkar; Figueroa, Ruben

2018-01-01

Retrospective analysis of the efficacy for two commonly used antibiotic regimens in the management of severe odontogenic infections. Evaluation of records of patients admitted to the Oral and Maxillofacial Surgery service at Boston University Medical Center from 2009 to 2014 with severe infections of odontogenic origin (SOI). Patients were divided into two groups based on the administered intravenous antibiotic: 1) Group I: Clindamycin only and 2) Group II: Penicillin and Metronidazole. Variables evaluated included demographic characteristics, ASA status, and anatomic site of infection risk, length of hospital stay, antibiotic failure, and pharmaceutical treatment cost. 78 patients (46 males and 32 females) were included in the study. There were 57 patients in group I (average age 32.6 years) and 21 in Group II (average age 32.8 years). The average white cell count at time of admission count was higher in Group I (19.3) versus Group II (17.4). Antibiotic failure rate was 3.5% in Group I and 4.7% for group 2 patients. Clindamycin alone and combination of Penicillin with Metronidazole are both effective pharmaceutical regimens for SOI. Clindamycin therapy resulted in shorter hospital stay and lower net treatment costs with a slightly higher success rate.

Water Lavage as an Adjunct to Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy (CRS-HIPEC)

PubMed Central

Gabriel, Emmanuel; Singla, Smit; Kim, Minhyung; Fisher, Daniel; Powers, Colin; Visioni, Anthony; Attwood, Kristopher; Skitzki, Joseph

2018-01-01

Background Water lavage (WL) during gastrointestinal cancer surgery has osmotically mediated lytic effects on tumor cells. We investigated the safety and efficacy of WL with CRS-HIPEC. Methods This is a retrospective review, 1/2003–7/2014, of a single institution experience with CRS-HIPEC comparing patients who had WL (WL+) to those who did not (WL−). Results Of 157 CRS-HIPECs, 16 (10.2%) were WL+. WL+ had more PCI scores > 20 compared to WL− (56.3% vs 19.4%, respectively, p=0.003); however, the completeness of cytoreduction (CC) was similar. There were no differences in hospital length of stay or post-operative complications. The average POD 1 sodium (Na) level was statistically lower in the WL+ group (133.6±2.5 vs 135.5±3.2 mEq/L, p=0.023); however, the average Na at discharge for each group was 140 mEq/L. There were no differences in 3-year OS (3WL+:0.63 vs WL−:0.68, p=0.97) or RFS (WL+:0.32 vs WL−:0.39, p=0.47). A subset analysis for patients with PCI > 20 showed no difference between groups. Conclusions WL offers a low cost, safe and theoretically efficacious method of tumor cell lysis for peritoneal malignancy. PMID:28622839

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

Vallis, Geoffrey K.

The project had two main components. The first concerns estimating the climate sensitivity in the presence of forcing uncertainty and natural variability. Climate sensitivity is the increase in the average surface temperature for a given increase in greenhouse gases, for example a doubling of carbon dioxide. We have provided new, probabilistic estimates of climate sensitivity using a simple climate model an the observed warming in the 20th century, in conjunction with ideas in data assimilation and parameter estimation developed in the engineering community. The estimates combine the uncertainty in the anthropogenic aerosols with the uncertainty arising because of natural variability.more » The second component concerns how the atmospheric circulation itself might change with anthropogenic global warming. We have shown that GCMs robustly predict an increase in the length scale of eddies, and we have also explored the dynamical mechanisms whereby there might be a shift in the latitude of the jet stream associated with anthropogenic warming. Such shifts in the jet might cause large changes in regional climate, potentially larger than the globally-averaged signal itself. We have also shown that the tropopause robustly increases in height with global warming, and that the Hadley Cell expands, and that the expansion of the Hadley Cell is correlated with the polewards movement of the mid-latitude jet.« less

Design and fabrication of segmented-in-series solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Lai, Tammy S.

Segmented-in-series solid oxide fuel cells (SS-SOFC) consist of several thick film cells deposited onto a porous, flattened tubular substrate. SS-SOFCs have a reduced need for gas-tight seals relative to planar SOFCs and can have a short current path compared to tubular SOFCs, limiting electrode ohmic resistance. Like tubular SOFCs, SS-SOFCs are suitable for stationary power generation. Their potentially small cell size makes them candidates for portable applications as well. The goals of this thesis project were to develop SS-SOFCs with 1-2 mm cell lengths and to analyze the effects of cell geometry and support current shunting on performance. Standard SOFC materials were chosen for the active components: yttria stabilized zirconia (YSZ) electrolyte; Ni-YSZ cermet anode; and (La,Sr)MnO 3-based cathode. A Pt-YSZ cermet was used as the interconnect material. Screen printing was the deposition method for all layers due to its low cost and patterning ability. A power density of >900 mW/cm2 was achieved with a cathode sheet resistance of ≈3 O/□ (≈90 mum LSM thickness). A D-optimal study was conducted to find processing conditions yielding substrates with ≥30 vol% porosity and high strength. Uniaxially pressed partially stabilized zirconia (PSZ) with 15 wt% starch pore former met the requirements, though 20 wt% graphite pore former was later found to give a smoother surface that improved screen printed layer quality. Calculations presented in this thesis take into account losses due to cell resistances, electrode ohmic resistances, interconnect resistance, and shunting by a weakly-conductive support material. Power density was maximized at an optimal cell length---it decreased at larger cell lengths due to electrode lateral resistance loss and at smaller cell lengths due to a decreasing fraction of cell active area. Assuming dimensions expected for screen printing and typical area specific resistances (RAS), optimal cell lengths typically ranged from 1 to 3 mm. The calculated and experimental values for the array RAS (active and inactive areas) showed similar dependences on cathode sheet resistance. The impact of shunting current increased with decreasing cell lengths. Shunting current was predicted to decrease array current by ˜10% for a 1.5 mm active cell length, though experimental measurements suggest that the calculation may overestimate the shunting effect.

Determining average path length and average trapping time on generalized dual dendrimer

NASA Astrophysics Data System (ADS)

Li, Ling; Guan, Jihong

2015-03-01

Dendrimer has wide number of important applications in various fields. In some cases during transport or diffusion process, it transforms into its dual structure named Husimi cactus. In this paper, we study the structure properties and trapping problem on a family of generalized dual dendrimer with arbitrary coordination numbers. We first calculate exactly the average path length (APL) of the networks. The APL increases logarithmically with the network size, indicating that the networks exhibit a small-world effect. Then we determine the average trapping time (ATT) of the trapping process in two cases, i.e., the trap placed on a central node and the trap is uniformly distributed in all the nodes of the network. In both case, we obtain explicit solutions of ATT and show how they vary with the networks size. Besides, we also discuss the influence of the coordination number on trapping efficiency.

Numerical prediction of algae cell mixing feature in raceway ponds using particle tracing methods.

PubMed

Ali, Haider; Cheema, Taqi A; Yoon, Ho-Sung; Do, Younghae; Park, Cheol W

2015-02-01

In the present study, a novel technique, which involves numerical computation of the mixing length of algae particles in raceway ponds, was used to evaluate the mixing process. A value of mixing length that is higher than the maximum streamwise distance (MSD) of algae cells indicates that the cells experienced an adequate turbulent mixing in the pond. A coupling methodology was adapted to map the pulsating effects of a 2D paddle wheel on a 3D raceway pond in this study. The turbulent mixing was examined based on the computations of mixing length, residence time, and algae cell distribution in the pond. The results revealed that the use of particle tracing methodology is an improved approach to define the mixing phenomenon more effectively. Moreover, the algae cell distribution aided in identifying the degree of mixing in terms of mixing length and residence time. © 2014 Wiley Periodicals, Inc.

Improved laparoscopic nephron-sparing surgery for renal cell carcinoma based on the precise anatomy of the nephron.

PubMed

Guo, Gang; Cai, Wei; Zhang, Xu

2016-11-01

The aim of the present study was to investigate a method of laparoscopic nephron-sparing surgery (LNSS) for renal cell carcinoma (RCC) based on the precise anatomy of the nephron, and to decrease the incidence of hemorrhage and urinary leakage. Between January 2012 and December 2013, 31 patients who presented to the General Hospital of the People's Liberation Army (Beijing, China) were treated for RCC. The mean tumor size was 3.4±0.7 cm in diameter (range, 1.2-6.0 cm). During surgery, the renal artery was blocked, and subsequently, an incision in the renal capsule and renal cortex was performed, at 3-5 mm from the tumor edge. Subsequent to the incision of the renal parenchyma, scissors with blunt and sharp edge were used to separate the base of the tumor from the normal renal medulla, in the direction of the ray medullary in the renal pyramids. The basal blood vessels were incised following the hemostasis of the region using bipolar coagulation. The minor renal calyces were stripped carefully and the wound was closed with an absorbable sutures. The arterial occlusion time, duration of surgery, intraoperative bleeding volume, post-operative drainage volume, pathological results and complications were recorded. The surgery was successful for all patients. The estimated average intraoperative bleeding volume was 55.7 ml, the average surgical duration was 95.5 min, the average arterial occlusion time was 21.2 min, the average post-operative drainage volume was 92.3 ml and the average post-operative length of hospital stay was 6.1 days. No hemorrhage or urinary leakage was observed in the patients following the surgery. LNSS for RCC based on the precise anatomy of the nephron was concluded to be effective and feasible. The surgery is useful for the complete removal of tumors and guarantees a negative margin, which may also decrease the incidence of hemorrhage and urinary leakage following surgery.

Analysis of the age of Panax ginseng based on telomere length and telomerase activity.

PubMed

Liang, Jiabei; Jiang, Chao; Peng, Huasheng; Shi, Qinghua; Guo, Xiang; Yuan, Yuan; Huang, Luqi

2015-01-23

Ginseng, which is the root of Panax ginseng (Araliaceae), has been used in Oriental medicine as a stimulant and dietary supplement for more than 7,000 years. Older ginseng plants are substantially more medically potent, but ginseng age can be simulated using unscrupulous cultivation practices. Telomeres progressively shorten with each cell division until they reach a critical length, at which point cells enter replicative senescence. However, in some cells, telomerase maintains telomere length. In this study, to determine whether telomere length reflects ginseng age and which tissue is best for such an analysis, we examined telomerase activity in the main roots, leaves, stems, secondary roots and seeds of ginseng plants of known age. Telomere length in the main root (approximately 1 cm below the rhizome) was found to be the best indicator of age. Telomeric terminal restriction fragment (TRF) lengths, which are indicators of telomere length, were determined for the main roots of plants of different ages through Southern hybridization analysis. Telomere length was shown to be positively correlated with plant age, and a simple mathematical model was formulated to describe the relationship between telomere length and age for P. ginseng.

The Association between Health Information Technology Adoption and Family Physicians' Practice Patterns in Canada: Evidence from 2007 and 2010 National Physician Surveys

PubMed Central

Sarma, Sisira; Hajizadeh, Mohammad; Thind, Amardeep; Chan, Rick

2013-01-01

Objective: To describe the association between health information technology (HIT) adoption and family physicians' patient visit length in Canada after controlling for physician and practice characteristics. Method: HIT adoption is defined in terms of four types of HIT usage: no HIT use (NO), basic HIT use without electronic medical record system (HIT), basic HIT use with electronic medical record (EMR) and advanced HIT use (EMR + HIT). The outcome variable is the average time spent on a patient visit (visit length). The data for this study came from the 2007 and 2010 National Physician Surveys. A log-linear model was used to analyze our visit length outcome. Results: The average time worked per week was found to be in the neighbourhood of 36 hours in both 2007 and 2010, but users of EMR and EMR + HIT were undertaking fewer patient visits per week relative to NO users. Multivariable analysis showed that EMR and EMR + HIT were associated with longer average time spent per patient visit by about 7.7% (p<0.05) and 6.7% (p<0.01), respectively, compared to NO users in 2007. In 2010, EMR was not statistically significant and EMR + HIT was associated with a 4% (p<0.1) increased visit length. A variety of practice-related variables such as the mode of remuneration, work setting and interprofessional practice influenced visit length in the expected direction. Conclusion: Use of HIT is found to be associated with fewer patient visits and longer visit length among family physicians in Canada relative to NO users, but this association weakened in the multivariable analysis of 2010. PMID:23968677

On the structural properties of small-world networks with range-limited shortcut links

NASA Astrophysics Data System (ADS)

Jia, Tao; Kulkarni, Rahul V.

2013-12-01

We explore a new variant of Small-World Networks (SWNs), in which an additional parameter (r) sets the length scale over which shortcuts are uniformly distributed. When r=0 we have an ordered network, whereas r=1 corresponds to the original Watts-Strogatz SWN model. These limited range SWNs have a similar degree distribution and scaling properties as the original SWN model. We observe the small-world phenomenon for r≪1, indicating that global shortcuts are not necessary for the small-world effect. For limited range SWNs, the average path length changes nonmonotonically with system size, whereas for the original SWN model it increases monotonically. We propose an expression for the average path length for limited range SWNs based on numerical simulations and analytical approximations.

Telomere shortening associated with chromosome instability is arrested in immortal cells which express telomerase activity.

PubMed Central

Counter, C M; Avilion, A A; LeFeuvre, C E; Stewart, N G; Greider, C W; Harley, C B; Bacchetti, S

1992-01-01

Loss of telomeric DNA during cell proliferation may play a role in ageing and cancer. Since telomeres permit complete replication of eukaryotic chromosomes and protect their ends from recombination, we have measured telomere length, telomerase activity and chromosome rearrangements in human cells before and after transformation with SV40 or Ad5. In all mortal populations, telomeres shortened by approximately 65 bp/generation during the lifespan of the cultures. When transformed cells reached crisis, the length of the telomeric TTAGGG repeats was only approximately 1.5 kbp and many dicentric chromosomes were observed. In immortal cells, telomere length and frequency of dicentric chromosomes stabilized after crisis. Telomerase activity was not detectable in control or extended lifespan populations but was present in immortal populations. These results suggest that chromosomes with short (TTAGGG)n tracts are recombinogenic, critically shortened telomeres may be incompatible with cell proliferation and stabilization of telomere length by telomerase may be required for immortalization. Images PMID:1582420

Immunohistochemical, morphological and histometrical analyses of follicular development in Astyanax bimaculatus (Teleostei: Characidae) exposed to an organochlorine insecticide.

PubMed

Marcon, Lucas; Thomé, Ralph Gruppi; Mounteer, Ann Honor; Bazzoli, Nilo; Rizzo, Elizete; Benjamin, Laércio Dos Anjos

2017-09-01

Thiodan ® is an organochlorine insecticide used in agriculture that can reach aquatic ecosystems where it can affect fish reproduction. This research aimed to evaluate follicular development and the expression of integrin β1, collagen type IV and caspase 3 by morphological, histometrical and immunohistochemical analyses of Astyanax bimaculatus exposed to Thiodan ® . Treatments included three sublethal concentrations of Thiodan ® (1.15, 2.30, and 5.60μgL -1 ) for 96h and a control without the insecticide. Mature females with ovaries in advanced follicular development were chosen for study (average weight: 11.52 ± 2.0g; average total length: 9.12 ± 0.64cm). The follicles of A. bimaculatus exhibited normal morphology, while the diameters of secondary follicles showed an increase (P< 0.05) in all concentrations when compared to the control group; a characteristic of follicles undergoing the initial stages of intoxication. Immunohistochemical analysis revealed secondary follicles with greater expression of integrin β1 and collagen type IV in cytoplasm of follicular cells than in the primary follicles in all treatments and in the control. Immunolocalization of caspase 3 was detected in follicular cells during secondary development in all tested concentrations of Thiodan ® and the control. These analyses demonstrate positive immunolocalization throughout the course of follicular development, even in fish exposed to varying concentrations of Thiodan ® for 96h, demonstrating that follicular cells retain their physiological integrity. Copyright © 2017 Elsevier Inc. All rights reserved.

Paternal age and telomere length in twins: the germ stem cell selection paradigm

PubMed Central

Hjelmborg, Jacob B; Dalgård, Christine; Mangino, Massimo; Spector, Tim D; Halekoh, Ulrich; Möller, Sören; Kimura, Masayuki; Horvath, Kent; Kark, Jeremy D; Christensen, Kaare; Kyvik, Kirsten O; Aviv, Abraham

2015-01-01

Telomere length, a highly heritable trait, is longer in offspring of older fathers. This perplexing feature has been attributed to the longer telomeres in sperm of older men and it might be an ‘epigenetic’ mechanism through which paternal age plays a role in telomere length regulation in humans. Based on two independent (discovery and replication) twin studies, comprising 889 twin pairs, we show an increase in the resemblance of leukocyte telomere length between dizygotic twins of older fathers, which is not seen in monozygotic twins. This phenomenon might result from a paternal age-dependent germ stem cell selection process, whereby the selected stem cells have longer telomeres, are more homogenous with respect to telomere length, and share resistance to aging. PMID:25865872

Computing the Length of the Shortest Telomere in the Nucleus

NASA Astrophysics Data System (ADS)

Dao Duc, K.; Holcman, D.

2013-11-01

The telomere length can either be shortened or elongated by an enzyme called telomerase after each cell division. Interestingly, the shortest telomere is involved in controlling the ability of a cell to divide. Yet, its dynamics remains elusive. We present here a stochastic approach where we model this dynamics using a Markov jump process. We solve the forward Fokker-Planck equation to obtain the steady state distribution and the statistical moments of telomere lengths. We focus specifically on the shortest one and we estimate its length difference with the second shortest telomere. After extracting key parameters such as elongation and shortening dynamics from experimental data, we compute the length of telomeres in yeast and obtain as a possible prediction the minimum concentration of telomerase required to ensure a proper cell division.

In-ground operation of Geothermic Fuel Cells for unconventional oil and gas recovery

NASA Astrophysics Data System (ADS)

Sullivan, Neal; Anyenya, Gladys; Haun, Buddy; Daubenspeck, Mark; Bonadies, Joseph; Kerr, Rick; Fischer, Bernhard; Wright, Adam; Jones, Gerald; Li, Robert; Wall, Mark; Forbes, Alan; Savage, Marshall

2016-01-01

This paper presents operating and performance characteristics of a nine-stack solid-oxide fuel cell combined-heat-and-power system. Integrated with a natural-gas fuel processor, air compressor, reactant-gas preheater, and diagnostics and control equipment, the system is designed for use in unconventional oil-and-gas processing. Termed a ;Geothermic Fuel Cell; (GFC), the heat liberated by the fuel cell during electricity generation is harnessed to process oil shale into high-quality crude oil and natural gas. The 1.5-kWe SOFC stacks are packaged within three-stack GFC modules. Three GFC modules are mechanically and electrically coupled to a reactant-gas preheater and installed within the earth. During operation, significant heat is conducted from the Geothermic Fuel Cell to the surrounding geology. The complete system was continuously operated on hydrogen and natural-gas fuels for ∼600 h. A quasi-steady operating point was established to favor heat generation (29.1 kWth) over electricity production (4.4 kWe). Thermodynamic analysis reveals a combined-heat-and-power efficiency of 55% at this condition. Heat flux to the geology averaged 3.2 kW m-1 across the 9-m length of the Geothermic Fuel Cell-preheater assembly. System performance is reviewed; some suggestions for improvement are proposed.

Amyloplast sedimentation dynamics in maize columella cells support a new model for the gravity-sensing apparatus of roots

NASA Technical Reports Server (NTRS)

Yoder, T. L.; Zheng, H. Q.; Todd, P.; Staehelin, L. A.

2001-01-01

Quantitative analysis of statolith sedimentation behavior was accomplished using videomicroscopy of living columella cells of corn (Zea mays) roots, which displayed no systematic cytoplasmic streaming. Following 90 degrees rotation of the root, the statoliths moved downward along the distal wall and then spread out along the bottom with an average velocity of 1.7 microm min(-1). When statolith trajectories traversed the complete width or length of the cell, they initially moved horizontally toward channel-initiation sites and then moved vertically through the channels to the lower side of the reoriented cell where they again dispersed. These statoliths exhibited a significantly lower average velocity than those sedimenting on distal-to-side trajectories. In addition, although statoliths undergoing distal-to-side sedimentation began at their highest velocity and slowed monotonically as they approached the lower cell membrane, statoliths crossing the cell's central region remained slow initially and accelerated to maximum speed once they reached a channel. The statoliths accelerated sooner, and the channeling effect was less pronounced in roots treated with cytochalasin D. Parallel ultrastructural studies of high-pressure frozen-freeze-substituted columella cells suggest that the low-resistance statolith pathway in the cell periphery corresponds to the sharp interface between the endoplasmic reticulum (ER)-rich cortical and the ER-devoid central region of these cells. The central region is also shown to contain an actin-based cytoskeletal network in which the individual, straight, actin-like filaments are randomly distributed. To explain these findings as well as the results of physical simulation experiments, we have formulated a new, tensegrity-based model of gravity sensing in columella cells. This model envisages the cytoplasm as pervaded by an actin-based cytoskeletal network that is denser in the ER-devoid central region than in the ER-rich cell cortex and is linked to stretch receptors in the plasma membrane. Sedimenting statoliths are postulated to produce a directional signal by locally disrupting the network and thereby altering the balance of forces acting on the receptors in different plasma membrane regions.

Amyloplast Sedimentation Dynamics in Maize Columella Cells Support a New Model for the Gravity-Sensing Apparatus of Roots1

PubMed Central

Yoder, Thomas L.; Zheng, Hui-qiong; Todd, Paul; Staehelin, L. Andrew

2001-01-01

Quantitative analysis of statolith sedimentation behavior was accomplished using videomicroscopy of living columella cells of corn (Zea mays) roots, which displayed no systematic cytoplasmic streaming. Following 90° rotation of the root, the statoliths moved downward along the distal wall and then spread out along the bottom with an average velocity of 1.7 μm min−1. When statolith trajectories traversed the complete width or length of the cell, they initially moved horizontally toward channel-initiation sites and then moved vertically through the channels to the lower side of the reoriented cell where they again dispersed. These statoliths exhibited a significantly lower average velocity than those sedimenting on distal-to-side trajectories. In addition, although statoliths undergoing distal-to-side sedimentation began at their highest velocity and slowed monotonically as they approached the lower cell membrane, statoliths crossing the cell's central region remained slow initially and accelerated to maximum speed once they reached a channel. The statoliths accelerated sooner, and the channeling effect was less pronounced in roots treated with cytochalasin D. Parallel ultrastructural studies of high-pressure frozen-freeze-substituted columella cells suggest that the low-resistance statolith pathway in the cell periphery corresponds to the sharp interface between the endoplasmic reticulum (ER)-rich cortical and the ER-devoid central region of these cells. The central region is also shown to contain an actin-based cytoskeletal network in which the individual, straight, actin-like filaments are randomly distributed. To explain these findings as well as the results of physical simulation experiments, we have formulated a new, tensegrity-based model of gravity sensing in columella cells. This model envisages the cytoplasm as pervaded by an actin-based cytoskeletal network that is denser in the ER-devoid central region than in the ER-rich cell cortex and is linked to stretch receptors in the plasma membrane. Sedimenting statoliths are postulated to produce a directional signal by locally disrupting the network and thereby altering the balance of forces acting on the receptors in different plasma membrane regions. PMID:11161060

Amyloplast sedimentation dynamics in maize columella cells support a new model for the gravity-sensing apparatus of roots.

PubMed

Yoder, T L; Zheng, H Q; Todd, P; Staehelin, L A

2001-02-01

Quantitative analysis of statolith sedimentation behavior was accomplished using videomicroscopy of living columella cells of corn (Zea mays) roots, which displayed no systematic cytoplasmic streaming. Following 90 degrees rotation of the root, the statoliths moved downward along the distal wall and then spread out along the bottom with an average velocity of 1.7 microm min(-1). When statolith trajectories traversed the complete width or length of the cell, they initially moved horizontally toward channel-initiation sites and then moved vertically through the channels to the lower side of the reoriented cell where they again dispersed. These statoliths exhibited a significantly lower average velocity than those sedimenting on distal-to-side trajectories. In addition, although statoliths undergoing distal-to-side sedimentation began at their highest velocity and slowed monotonically as they approached the lower cell membrane, statoliths crossing the cell's central region remained slow initially and accelerated to maximum speed once they reached a channel. The statoliths accelerated sooner, and the channeling effect was less pronounced in roots treated with cytochalasin D. Parallel ultrastructural studies of high-pressure frozen-freeze-substituted columella cells suggest that the low-resistance statolith pathway in the cell periphery corresponds to the sharp interface between the endoplasmic reticulum (ER)-rich cortical and the ER-devoid central region of these cells. The central region is also shown to contain an actin-based cytoskeletal network in which the individual, straight, actin-like filaments are randomly distributed. To explain these findings as well as the results of physical simulation experiments, we have formulated a new, tensegrity-based model of gravity sensing in columella cells. This model envisages the cytoplasm as pervaded by an actin-based cytoskeletal network that is denser in the ER-devoid central region than in the ER-rich cell cortex and is linked to stretch receptors in the plasma membrane. Sedimenting statoliths are postulated to produce a directional signal by locally disrupting the network and thereby altering the balance of forces acting on the receptors in different plasma membrane regions.

HIV enteropathy: crypt stem and transit cell hyperproliferation induces villous atrophy in HIV/Microsporidia-infected jejunal mucosa.

PubMed

Batman, Philip A; Kotler, Donald P; Kapembwa, Moses S; Booth, Dawn; Potten, Christopher S; Orenstein, Jan M; Scally, Andrew J; Griffin, George E

2007-02-19

The study aim was to analyse the kinetics of stem and transit cells in the crypts of jejunal mucosa infected with HIV and Microsporidia. The size of villi, depth of crypts and proliferative activity of transit and stem cells in jejunal mucosa were measured using morphometric techniques. The surface area/volume ratio (S/V) of jejunal biopsies was estimated under light microscopy using a Weibel graticule. Crypt length was measured by counting enterocytes along the crypt side from the base to the villus junction, and the mean crypt length was calculated. The S/V and crypt lengths of the jejunal mucosa of 21 HIV and Microsporidia-infected test cases were compared with 14 control cases. The labelling index in relation to the crypt cell position of 10 of the test cases was analysed compared with 13 control cases. Differences were found in the S/V and crypt length, and there was a negative correlation between S/V and crypt length in test and control cases combined. Cell labelling indices fell into low and high proliferation groups. There were significant differences in labelling indices between low proliferation test cases and controls, between high proliferation test cases and controls, and between high and low proliferation test cases. Villous atrophy induced by HIV and Microsporidia is attributed to crypt cell hyperplasia and the encroachment of crypt cells onto villi. These infections induce crypt hypertrophy by stimulating cell mitosis predominantly in transit cells but also in stem cells. Increased stem cell proliferation occurs only in high proliferation cases.

Probing cooperative force generation in collective cancer invasion

NASA Astrophysics Data System (ADS)

Alobaidi, Amani A.; Xu, Yaopengxiao; Chen, Shaohua; Jiao, Yang; Sun, Bo

2017-08-01

Collective cellular dynamics in the three-dimensional extracellular matrix (ECM) plays a crucial role in many physiological processes such as cancer invasion. Both chemical and mechanical signaling support cell-cell communications on a variety of length scales, leading to collective migratory behaviors. Here we conduct experiments using 3D in vitro tumor models and develop a phenomenological model in order to probe the cooperativity of force generation in the collective invasion of breast cancer cells. In our model, cell-cell communication is characterized by a single parameter that quantifies the correlation length of cellular migration cycles. We devise a stochastic reconstruction method to generate realizations of cell colonies with specific contraction phase correlation functions and correlation length a. We find that as a increases, the characteristic size of regions containing cells with similar contraction phases grows. For small a values, the large fluctuations in individual cell contraction phases smooth out the temporal fluctuations in the time-dependent deformation field in the ECM. For large a values, the periodicity of an individual cell contraction cycle is clearly manifested in the temporal variation of the overall deformation field in the ECM. Through quantitative comparisons of the simulated and experimentally measured deformation fields, we find that the correlation length for collective force generation in the breast cancer diskoid in geometrically micropatterned ECM (DIGME) system is a≈ 25~μ \\text{m} , which is roughly twice the linear size of a single cell. One possible mechanism for this intermediate cell correlation length is the fiber-mediated stress propagation in the 3D ECM network in the DIGME system.

Damage and recovery characteristics of lithium-containing solar cells.

NASA Technical Reports Server (NTRS)

Faith, T. J.

1971-01-01

Damage and recovery characteristics were measured on lithium-containing solar cells irradiated by 1-MeV electrons. Empirical expressions for cell recovery time, diffusion-length damage coefficient immediately after irradiation, and diffusion-length damage coefficient after recovery were derived using results of short-circuit current, diffusion-length, and reverse-bias capacitance measurements. The damage coefficients were expressed in terms of a single lithium density parameter, the lithium gradient. A fluence dependence was also established, this dependence being the same for both the immediate-post-irradiation and post-recovery cases. Cell recovery rates were found to increase linearly with lithium gradient.

Fully Coupled Simulation of Lithium Ion Battery Cell Performance

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

Trembacki, Bradley L.; Murthy, Jayathi Y.; Roberts, Scott Alan

Lithium-ion battery particle-scale (non-porous electrode) simulations applied to resolved electrode geometries predict localized phenomena and can lead to better informed decisions on electrode design and manufacturing. This work develops and implements a fully-coupled finite volume methodology for the simulation of the electrochemical equations in a lithium-ion battery cell. The model implementation is used to investigate 3D battery electrode architectures that offer potential energy density and power density improvements over traditional layer-by-layer particle bed battery geometries. Advancement of micro-scale additive manufacturing techniques has made it possible to fabricate these 3D electrode microarchitectures. A variety of 3D battery electrode geometries are simulatedmore » and compared across various battery discharge rates and length scales in order to quantify performance trends and investigate geometrical factors that improve battery performance. The energy density and power density of the 3D battery microstructures are compared in several ways, including a uniform surface area to volume ratio comparison as well as a comparison requiring a minimum manufacturable feature size. Significant performance improvements over traditional particle bed electrode designs are observed, and electrode microarchitectures derived from minimal surfaces are shown to be superior. A reduced-order volume-averaged porous electrode theory formulation for these unique 3D batteries is also developed, allowing simulations on the full-battery scale. Electrode concentration gradients are modeled using the diffusion length method, and results for plate and cylinder electrode geometries are compared to particle-scale simulation results. Additionally, effective diffusion lengths that minimize error with respect to particle-scale results for gyroid and Schwarz P electrode microstructures are determined.« less

The spatial extent of excitatory and inhibitory zones in the receptive field of superficial layer hypercomplex cells

PubMed Central

Sillito, A. M.

1977-01-01

1. An investigation has been made of the extent of inhibitory and excitatory components in the receptive field of superficial layer hypercomplex cells in the cat's striate cortex and the relation of the components to the length preference exhibited by these cells. 2. Maximal responses were produced by an optimal length stimulus moving through a restricted region of the receptive field. The length of this receptive field region was less than the total length of the excitatory zone as mapped with a very short slit. Slits of similar length to the excitatory zone produced a smaller response than an optimal length slit. 3. An increase of slit length so that it passed over receptive field regions either side of the excitatory zone resulted in an elimination of the response. When background discharge levels were increased by the iontophoretic application of D, L-homocysteic acid slits of this length were observed to produce a suppression of the resting discharge as they passed over the receptive field. They did not modify the resting discharge level when it was induced by the iontophoretic application of the GABA antagonist bicuculline. This data is taken to indicate that long slits activate a powerful post-synaptic inhibitory input to the cell. 4. Maximal inhibitory effects were only observed if the testing slit passed over the receptive field centre. That is slits with a gap positioned midway along their length so as to exclude the optimal excitatory response region surprisingly tended to produce excitatory effects rather than the expected inhibitory effects. It appears that simultaneous stimulation of the receptive field centre is a precondition for the inhibitory effect of stimulation of regions either side of the excitatory zone to be activated. 5. It is suggested that the interneurones mediating the inhibitory input to the superficial layer hypercomplex cells are driven both by cells in adjacent hypercolumns with receptive fields spatially displaced to either side of the excitatory zone and by cells in the same column, optimal inhibitory effects only being achieved when both sets of input to the interneurone are activated. PMID:604459

Telomere lengthening and other functions of telomerase.

PubMed

Rubtsova, M P; Vasilkova, D P; Malyavko, A N; Naraikina, Yu V; Zvereva, M I; Dontsova, O A

2012-04-01

Telomerase is an enzyme that maintains the length of the telomere. The telomere length specifies the number of divisions a cell can undergo before it finally dies (i.e. the proliferative potential of cells). For example, telomerase is activated in embryonic cell lines and the telomere length is maintained at a constant level; therefore, these cells have an unlimited fission potential. Stem cells are characterized by a lower telomerase activity, which enables only partial compensation for the shortening of telomeres. Somatic cells are usually characterized by the absence of telomerase activity. Telomere shortening leads to the attainment of the Hayflick limit, the transition of cells to a state of senescence. The cells subsequently enter a state of crisis, accompanied by massive cell death. The surviving cells become cancer cells, which are capable both of dividing indefinitely and maintaining telomere length (usually with the aid of telomerase). Telomerase is a reverse transcriptase. It consists of two major components: telomerase RNA (TER) and reverse transcriptase (TERT). TER is a non-coding RNA, and it contains the region which serves as a template for telomere synthesis. An increasing number of articles focussing on the alternative functions of telomerase components have recently started appearing. The present review summarizes data on the structure, biogenesis, and functions of telomerase.

Retinal nerve fiber layer measurements by scanning laser polarimetry with enhanced corneal compensation in healthy subjects.

PubMed

Rao, Harsha L; Venkatesh, Chirravuri R; Vidyasagar, Kelli; Yadav, Ravi K; Addepalli, Uday K; Jude, Aarthi; Senthil, Sirisha; Garudadri, Chandra S

2014-12-01

To evaluate the (i) effects of biological (age and axial length) and instrument-related [typical scan score (TSS) and corneal birefringence] parameters on the retinal nerve fiber layer (RNFL) measurements and (ii) repeatability of RNFL measurements with the enhanced corneal compensation (ECC) protocol of scanning laser polarimetry (SLP) in healthy subjects. In a cross-sectional study, 140 eyes of 73 healthy subjects underwent RNFL imaging with the ECC protocol of SLP. Linear mixed modeling methods were used to evaluate the effects of age, axial length, TSS, and corneal birefringence on RNFL measurements. One randomly selected eye of 48 subjects from the cohort underwent 3 serial scans during the same session to determine the repeatability. Age significantly influenced all RNFL measurements. RNFL measurements decreased by 1 µm for every decade increase in age. TSS affected the overall average RNFL measurement (β=-0.62, P=0.003), whereas residual anterior segment retardance affected the superior quadrant measurement (β=1.14, P=0.01). Axial length and corneal birefringence measurements did not influence RNFL measurements. Repeatability, as assessed by the coefficient of variation, ranged between 1.7% for the overall average RNFL measurement and 11.4% for th nerve fiber indicator. Age significantly affected all RNFL measurements with the ECC protocol of SLP, whereas TSS and residual anterior segment retardance affected the overall average and the superior average RNFL measurements, respectively. Axial length and corneal birefringence measurements did not influence any RNFL measurements. RNFL measurements had good intrasession repeatability. These results are important while evaluating the change in structural measurements over time in glaucoma patients.

Tula hantavirus isolate with the full-length ORF for nonstructural protein NSs survives for more consequent passages in interferon-competent cells than the isolate having truncated NSs ORF.

PubMed

Jääskeläinen, Kirsi M; Plyusnina, Angelina; Lundkvist, Ake; Vaheri, Antti; Plyusnin, Alexander

2008-01-11

The competitiveness of two Tula hantavirus (TULV) isolates, TULV/Lodz and TULV/Moravia, was evaluated in interferon (IFN) -competent and IFN-deficient cells. The two isolates differ in the length of the open reading frame (ORF) encoding the nonstructural protein NSs, which has previously been shown to inhibit IFN response in infected cells. In IFN-deficient Vero E6 cells both TULV isolates survived equally well. In contrast, in IFN-competent MRC5 cells TULV/Lodz isolate, that possesses the NSs ORF for the full-length protein of 90 aa, survived for more consequent passages than TULV/Moravia isolate, which contains the ORF for truncated NSs protein (66-67 aa). Our data show that expression of a full-length NSs protein is beneficial for the virus survival and competitiveness in IFN-competent cells and not essential in IFN-deficient cells. These results suggest that the N-terminal aa residues are important for the full activity of the NSs protein.

Strigolactones Stimulate Internode Elongation Independently of Gibberellins1[C][W

PubMed Central

de Saint Germain, Alexandre; Ligerot, Yasmine; Dun, Elizabeth A.; Pillot, Jean-Paul; Ross, John J.; Beveridge, Christine A.; Rameau, Catherine

2013-01-01

Strigolactone (SL) mutants in diverse species show reduced stature in addition to their extensive branching. Here, we show that this dwarfism in pea (Pisum sativum) is not attributable to the strong branching of the mutants. The continuous supply of the synthetic SL GR24 via the root system using hydroponics can restore internode length of the SL-deficient rms1 mutant but not of the SL-response rms4 mutant, indicating that SLs stimulate internode elongation via RMS4. Cytological analysis of internode epidermal cells indicates that SLs control cell number but not cell length, suggesting that SL may affect stem elongation by stimulating cell division. Consequently, SLs can repress (in axillary buds) or promote (in the stem) cell division in a tissue-dependent manner. Because gibberellins (GAs) increase internode length by affecting both cell division and cell length, we tested if SLs stimulate internode elongation by affecting GA metabolism or signaling. Genetic analyses using SL-deficient and GA-deficient or DELLA-deficient double mutants, together with molecular and physiological approaches, suggest that SLs act independently from GAs to stimulate internode elongation. PMID:23943865

Analysis of copy number variations in Holstein-Friesian cow genomes based on whole-genome sequence data.

PubMed

Mielczarek, M; Frąszczak, M; Giannico, R; Minozzi, G; Williams, John L; Wojdak-Maksymiec, K; Szyda, J

2017-07-01

Thirty-two whole genome DNA sequences of cows were analyzed to evaluate inter-individual variability in the distribution and length of copy number variations (CNV) and to functionally annotate CNV breakpoints. The total number of deletions per individual varied between 9,731 and 15,051, whereas the number of duplications was between 1,694 and 5,187. Most of the deletions (81%) and duplications (86%) were unique to a single cow. No relation between the pattern of variant sharing and a family relationship or disease status was found. The animal-averaged length of deletions was from 5,234 to 9,145 bp and the average length of duplications was between 7,254 and 8,843 bp. Highly significant inter-individual variation in length and number of CNV was detected for both deletions and duplications. The majority of deletion and duplication breakpoints were located in intergenic regions and introns, whereas fewer were identified in noncoding transcripts and splice regions. Only 1.35 and 0.79% of the deletion and duplication breakpoints were observed within coding regions. A gene with the highest number of deletion breakpoints codes for protein kinase cGMP-dependent type I, whereas the T-cell receptor α constant gene had the most duplication breakpoints. The functional annotation of genes with the largest incidence of deletion/duplication breakpoints identified 87/112 Kyoto Encyclopedia of Genes and Genomes pathways, but none of the pathways were significantly enriched or depleted with breakpoints. The analysis of Gene Ontology (GO) terms revealed that a cluster with the highest enrichment score among genes with many deletion breakpoints was represented by GO terms related to ion transport, whereas the GO term cluster mostly enriched among the genes with many duplication breakpoints was related to binding of macromolecules. Furthermore, when considering the number of deletion breakpoints per gene functional category, no significant differences were observed between the "housekeeping" and "strong selection" categories, but genes representing the "low selection pressure" group showed a significantly higher number of breakpoints. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Structural and rectifying junction properties of self-assembled ZnO nanoparticles in polystyrene diblock copolymers on (1 0 0)Si substrates

NASA Astrophysics Data System (ADS)

Ali, H. A.; Iliadis, A. A.; Martinez-Miranda, L. J.; Lee, U.

2006-06-01

The structural and electronic transport properties of self-assembled ZnO nanoparticles in polystyrene-acrylic acid, [PS] m/[PAA] n, diblock copolymer on p-type (1 0 0)Si substrates are reported for the first time. Four different block repeat unit ratios ( m/ n) of 159/63, 139/17,106/17, and 106/4, were examined in order to correlate the physical parameters (size, density) of the nanoparticles with the copolymer block lengths m and n. We established that the self-assembled ZnO nanoparticle average size increased linearly with minority block length n, while the average density decreased exponentially with majority block length m. Average size varied from 20 nm to 250 nm and average density from 3.5 × 10 7 cm -2 to 1 × 10 10 cm -2, depending on copolymer parameters. X-ray diffraction studies showed the particles to have a wurtzite crystal structure with the (1 0 0) being the dominant orientation. Room temperature current-voltage characteristics measured for an Al/ZnO-nanocomposite/Si structure exhibited rectifying junction properties and indicated the formation of Al/ZnO-nanocomposite Schottky type junction with a barrier height of 0.7 V.

Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation.

PubMed

Chu, Trang T T; Sinha, Ameya; Malleret, Benoit; Suwanarusk, Rossarin; Park, Jung E; Naidu, Renugah; Das, Rupambika; Dutta, Bamaprasad; Ong, Seow Theng; Verma, Navin K; Chan, Jerry K; Nosten, François; Rénia, Laurent; Sze, Siu K; Russell, Bruce; Chandramohanadas, Rajesh

2018-01-01

Erythropoiesis is marked by progressive changes in morphological, biochemical and mechanical properties of erythroid precursors to generate red blood cells (RBC). The earliest enucleated forms derived in this process, known as reticulocytes, are multi-lobular and spherical. As reticulocytes mature, they undergo a series of dynamic cytoskeletal re-arrangements and the expulsion of residual organelles, resulting in highly deformable biconcave RBCs (normocytes). To understand the significant, yet neglected proteome-wide changes associated with reticulocyte maturation, we undertook a quantitative proteomics approach. Immature reticulocytes (marked by the presence of surface transferrin receptor, CD71) and mature RBCs (devoid of CD71) were isolated from human cord blood using a magnetic separation procedure. After sub-fractionation into triton-extracted membrane proteins and luminal samples (isobaric tags for relative and absolute quantitation), quantitative mass spectrometry was conducted to identify more than 1800 proteins with good confidence and coverage. While most structural proteins (such as Spectrins, Ankyrin and Band 3) as well as surface glycoproteins were conserved, proteins associated with microtubule structures, such as Talin-1/2 and ß-Tubulin, were detected only in immature reticulocytes. Atomic force microscopy (AFM)-based imaging revealed an extended network of spectrin filaments in reticulocytes (with an average length of 48 nm), which shortened during reticulocyte maturation (average spectrin length of 41 nm in normocytes). The extended nature of cytoskeletal network may partly account for increased deformability and shape changes, as reticulocytes transform to normocytes. © 2017 John Wiley & Sons Ltd.

International variations in primary care physician consultation time: a systematic review of 67 countries

PubMed Central

Neves, Ana Luisa; Oishi, Ai; Tagashira, Hiroko; Verho, Anistasiya; Holden, John

2017-01-01

Objective To describe the average primary care physician consultation length in economically developed and low-income/middle-income countries, and to examine the relationship between consultation length and organisational-level economic, and health outcomes. Design and outcome measures This is a systematic review of published and grey literature in English, Chinese, Japanese, Spanish, Portuguese and Russian languages from 1946 to 2016, for articles reporting on primary care physician consultation lengths. Data were extracted and analysed for quality, and linear regression models were constructed to examine the relationship between consultation length and health service outcomes. Results One hundred and seventy nine studies were identified from 111 publications covering 28 570 712 consultations in 67 countries. Average consultation length differed across the world, ranging from 48 s in Bangladesh to 22.5 min in Sweden. We found that 18 countries representing about 50% of the global population spend 5 min or less with their primary care physicians. We also found significant associations between consultation length and healthcare spending per capita, admissions to hospital with ambulatory sensitive conditions such as diabetes, primary care physician density, physician efficiency and physician satisfaction. Conclusion There are international variations in consultation length, and it is concerning that a large proportion of the global population have only a few minutes with their primary care physicians. Such a short consultation length is likely to adversely affect patient healthcare and physician workload and stress. PMID:29118053

Further Insights into the Ciliary Gene and Protein KIZ and Its Murine Ortholog PLK1S1 Mutated in Rod-Cone Dystrophy

PubMed Central

Méjécase, Cécile; Bertelli, Matteo; Terray, Angélique; Michiels, Christelle; Condroyer, Christel; Fouquet, Stéphane; Sadoun, Maxime; Clérin, Emmanuelle; Liu, Binqian; Léveillard, Thierry; Goureau, Olivier; Sahel, José-Alain; Audo, Isabelle

2017-01-01

We identified herein additional patients with rod-cone dystrophy (RCD) displaying mutations in KIZ, encoding the ciliary centrosomal protein kizuna and performed functional characterization of the respective protein in human fibroblasts and of its mouse ortholog PLK1S1 in the retina. Mutation screening was done by targeted next generation sequencing and subsequent Sanger sequencing validation. KIZ mRNA levels were assessed on blood and serum-deprived human fibroblasts from a control individual and a patient, compound heterozygous for the c.52G>T (p.Glu18*) and c.119_122del (p.Lys40Ilefs*14) mutations in KIZ. KIZ localization, documentation of cilium length and immunoblotting were performed in these two fibroblast cell lines. In addition, PLK1S1 immunolocalization was conducted in mouse retinal cryosections and isolated rod photoreceptors. Analyses of additional RCD patients enabled the identification of two homozygous mutations in KIZ, the known c.226C>T (p.Arg76*) mutation and a novel variant, the c.3G>A (p.Met1?) mutation. Albeit the expression levels of KIZ were three-times lower in the patient than controls in whole blood cells, further analyses in control- and mutant KIZ patient-derived fibroblasts unexpectedly revealed no significant difference between the two genotypes. Furthermore, the averaged monocilia length in the two fibroblast cell lines was similar, consistent with the preserved immunolocalization of KIZ at the basal body of the primary cilia. Analyses in mouse retina and isolated rod photoreceptors showed PLK1S1 localization at the base of the photoreceptor connecting cilium. In conclusion, two additional patients with mutations in KIZ were identified, further supporting that defects in KIZ/PLK1S1, detected at the basal body of the primary cilia in fibroblasts, and the photoreceptor connecting cilium in mouse, respectively, are involved in RCD. However, albeit the mutations were predicted to lead to nonsense mediated mRNA decay, we could not detect changes upon expression levels, protein localization or cilia length in KIZ-mutated fibroblast cells. Together, our findings unveil the limitations of fibroblasts as a cellular model for RCD and call for other models such as induced pluripotent stem cells to shed light on retinal pathogenic mechanisms of KIZ mutations. PMID:29057815

Pulmonary cellular effects in rats following aerosol exposures to ultrafine Kevlar aramid fibrils: evidence for biodegradability of inhaled fibrils.

PubMed

Warheit, D B; Kellar, K A; Hartsky, M A

1992-10-01

Previous chronic inhalation studies have shown that high concentrations of Kevlar fibrils produced fibrosis and cystic keratinizing tumors in rats following 2-year inhalation exposures. The current studies were undertaken to evaluate mechanisms and to assess the toxicity of inhaled Kevlar fibrils relative to other reference materials. Rats were exposed to ultrafine Kevlar fibers (fibrils) for 3 or 5 days at concentrations ranging from 600-1300 fibers/cc (gravimetric concentrations ranging from 2-13 mg/m3). A complete characterization of the fiber aerosol and dose was carried out. These measurements included gravimetric concentrations, mass median aerodynamic diameter, fiber number, and count median lengths and diameters of the aerosol. Following exposures, cells and fluids from groups of sham- and fiber-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, lactate dehydrogenase (LDH), protein, and N-acetyl glucosaminidase (NAG) values were measured in BAL fluids at several time points postexposure. Alveolar macrophages were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy. The lungs of additional exposed animals were processed for deposition, cell labeling, retained dose, and lung clearance studies, as well as fiber dimensions (from digested lung tissue), histopathology, and transmission electron microscopy. Five-day exposures to Kevlar fibrils elicited a transient granulocytic inflammatory response with concomitant increases in BAL fluid levels of alkaline phosphatase, NAG, LDH, and protein. Unlike the data from silica and asbestos exposures where inflammation persisted, biochemical parameters returned to control levels at time intervals between 1 week and 1 month postexposure. Macrophage function in Kevlar-exposed alveolar macrophages was not significantly different from sham controls at any time period. Cell labeling studies were carried out immediately after exposure, as well as 1 week and 1 month postexposure. Increased pulmonary cell labeling was measured in terminal bronchiolar cells immediately after exposure but returned to control values 1 week later. Fiber clearance studies demonstrated a transient increase in the numbers of retained fibers at 1 week postexposure, with rapid clearance of fibers thereafter. The transient increase in the number of fibers could be due to transverse cleaving of the fibers, since the average lengths of retained fibers continued to decrease over time. In this regard, a progressive decrease in the mean lengths and diameters of inhaled fibers was measured over a 6-month postexposure period.(ABSTRACT TRUNCATED AT 400 WORDS)

Geographical variation in camper expenditures

Treesearch

Wilbur F. LaPage; Edward G. Fisher

1971-01-01

Daily expenditures by families camping in New Hampshire State parks in 1967 averaged $11.81. Considerable variation was found between the northern, central, and southern regions of the State in both the average amount of money spent and the way in which the money was spent. Daily expenditures in the north were higher, but average visit lengths were shorter, resulting...

14 CFR Appendix F to Part 25

Code of Federal Regulations, 2012 CFR

2012-01-01

... not exceed 6 inches and the average flame time after removal of the flame source may not exceed 15... means. The average burn length may not exceed 8 inches, and the average flame time after removal of the... Standards Institute, 1430 Broadway, New York, NY 10018). If the film travels through ducts, the ducts must...

14 CFR Appendix F to Part 25

Code of Federal Regulations, 2011 CFR

2011-01-01

... not exceed 6 inches and the average flame time after removal of the flame source may not exceed 15... means. The average burn length may not exceed 8 inches, and the average flame time after removal of the... Standards Institute, 1430 Broadway, New York, NY 10018). If the film travels through ducts, the ducts must...

14 CFR Appendix F to Part 25

Code of Federal Regulations, 2010 CFR

2010-01-01

... not exceed 6 inches and the average flame time after removal of the flame source may not exceed 15... means. The average burn length may not exceed 8 inches, and the average flame time after removal of the... Standards Institute, 1430 Broadway, New York, NY 10018). If the film travels through ducts, the ducts must...

14 CFR Appendix F to Part 25

Code of Federal Regulations, 2013 CFR

2013-01-01

... not exceed 6 inches and the average flame time after removal of the flame source may not exceed 15... means. The average burn length may not exceed 8 inches, and the average flame time after removal of the... Standards Institute, 1430 Broadway, New York, NY 10018). If the film travels through ducts, the ducts must...

Construction of cDNA library and preliminary analysis of expressed sequence tags from Siberian tiger

PubMed Central

Liu, Chang-Qing; Lu, Tao-Feng; Feng, Bao-Gang; Liu, Dan; Guan, Wei-Jun; Ma, Yue-Hui

2010-01-01

In this study we successfully constructed a full-length cDNA library from Siberian tiger, Panthera tigris altaica, the most well-known wild Animal. Total RNA was extracted from cultured Siberian tiger fibroblasts in vitro. The titers of primary and amplified libraries were 1.30×106 pfu/ml and 1.62×109 pfu/ml respectively. The proportion of recombinants from unamplified library was 90.5% and average length of exogenous inserts was 1.13 kb. A total of 282 individual ESTs with sizes ranging from 328 to 1,142bps were then analyzed the BLASTX score revealed that 53.9% of the sequences were classified as strong match, 38.6% as nominal and 7.4% as weak match. 28.0% of them were found to be related to enzyme/catalytic protein, 20.9% ESTs to metabolism, 13.1% ESTs to transport, 12.1% ESTs to signal transducer/cell communication, 9.9% ESTs to structure protein, 3.9% ESTs to immunity protein/defense metabolism, 3.2% ESTs to cell cycle, and 8.9 ESTs classified as novel genes. These results demonstrated that the reliability and representativeness of the cDNA library attained to the requirements of a standard cDNA library. This library provided a useful platform for the functional genomic research of Siberian tigers. PMID:20941376

Morphological and molecular description of Myxobolus batalhensis n. sp. (Myxozoa, Myxosporea), a liver and ovary parasite of Salminus hilarii in Brazil.

PubMed

Vieira, Diego Henrique Mirandola Dias; Alama-Bermejo, Gema; Bartholomew, Jerri Lee; Abdallah, Vanessa Doro; de Azevedo, Rodney Kozlowiski

2017-12-01

Plasmodia containing myxospores belonging to the genus Myxobolus Bütschli, 1882 were found in the ovaries and liver of Salminus hilarii. Despite its economic value, this fish host has no previous reports of myxozoan infections. Herein, we describe Myxobolus batalhensis n. sp. using morphological and ultrastructural data, as well as histological and SSU rDNA molecular data. The mature myxospores were elongated, measuring in average 15.2 ± 0.8 μm in length, 8.4 ± 0.4 μm in width, and 5.1 ± 0.2 μm in thickness. Polar capsules were elongated and measured 5.3 ± 0.3 μm in length and 2.8 ± 0.3 μm in width. Polar filaments had 6-9 coils. Histopathological analysis showed coagulation necrosis associated with cell lysis as a response of the host cell to the parasite in the ovaries. No inflammatory reaction was observed in the liver, although the presence of the plasmodia caused changes in tissue structure. The phylogenetic analysis of South American myxobolid species showed M. batalhensis n. sp. as sister species of Myxobolus aureus. This is the first report of a myxozoan species parasitizing S. hilarii and the first myxozoan species described in the Batalha river.

Quantification of telomere length by FISH and laser scanning cytometry

NASA Astrophysics Data System (ADS)

Mahoney, John E.; Sahin, Ergun; Jaskelioff, Mariela; Chin, Lynda; DePinho, Ronald A.; Protopopov, Alexei I.

2008-02-01

Telomeres play a critical role in the maintenance of chromosomal stability. Telomere erosion, coupled with loss of DNA damage checkpoint function, results in genomic instability that promotes the development of cancer. The critical role of telomere dynamics in cancer has motivated the development of technologies designed to monitor telomere reserves in a highly quantitative and high-throughput manner in humans and model organisms. To this end, we have adapted and modified two established technologies, telomere-FISH and laser scanning cytometry. Specifically, we have produced a number of enhancements to the iCys LSC (CompuCyte) package including software updates, use of 60X dry objectives, and increased spatial resolution by 0.2 um size of stage steps. In addition, the 633 nm HeNe laser was replaced with a 532 nm green diode laser to better match the viewing options. Utilization of telomere-deficient mouse cells with short dysfunctional telomeres and matched telomerase reconstituted cultures demonstrated significantly higher mean integral specific fluorescence values for mTR transfectants relative to empty vector controls: 4.485M vs. 1.362M (p<0.0001). Histograms of average telomere intensities for individual cells were obtained and demonstrated intercellular heterogeneity in telomere lengths. The validation of the approach derives from a strong correlation between iCys LSC values and Southern blotting. This validated method greatly increases our experimental throughput and objectivity.

Proper catheter selection for needle thoracostomy: a height and weight-based criteria.

PubMed

Powers, William F; Clancy, Thomas V; Adams, Ashley; West, Tonnya C; Kotwall, Cyrus A; Hope, William W

2014-01-01

Obesity increases the incidence of mortality in trauma patients. Current Advanced Trauma Life Support guidelines recommend using a 5-cm catheter at the second intercostal (ICS) space in the mid-clavicular line to treat tension pneumothoraces. Our study purpose was to determine whether body mass index (BMI) predicted the catheter length needed for needle thoracostomy. We retrospectively reviewed trauma patients undergoing chest computed tomography scans January 2004 through September 2006. A BMI was calculated for each patient, and the chest wall thickness (CWT) at the second ICS in the mid-clavicular line was measured bilaterally. Patients were grouped by BMI as underweight (≤ 18.5 kg/m2), normal weight (18.6-24.9 kg/m(2)), overweight (25-29.9 kg/m(2)), or obese (≥ 30 kg/m(2)). Three hundred twenty-six patients were included in the study; 70% were male. Ninety-four percent of patients experienced blunt trauma. Sixty-three percent of patients were involved in a motor vehicle collision. The average BMI was 29 [SD 7.8]. The average CWT was 6.2 [SD 1.9]cm on the right and 6.3 [SD 1.9]cm on the left. As BMI increased, a statistically significant (p<0.0001) CWT increase was observed in all BMI groups. There were no significant differences in ISS, ventilator days, ICU length of stay, or overall length of stay among the groups. As BMI increases, there is a direct correlation to increasing CWT. This information could be used to quickly select an appropriate needle length for needle thoracostomy. The average patient in our study would require a catheter length of 6-6.5 cm to successfully decompress a tension pneumothorax. There are not enough regionally available data to define the needle lengths needed for needle thoracostomy. Further study is required to assess the feasibility and safety of using varying catheter lengths. Copyright © 2013 Elsevier Ltd. All rights reserved.

The influence of uncemented femoral stem length and design on its primary stability: a finite element analysis.

PubMed

Reimeringer, M; Nuño, N; Desmarais-Trépanier, C; Lavigne, M; Vendittoli, P A

2013-01-01

One of the crucial factors for short- and long-term clinical success of total hip arthroplasty cementless implants is primary stability. Indeed, motion at the bone-implant interface above 40 μm leads to partial bone ingrowth, while motion exceeding 150 μm completely inhibits bone ingrowth. The aim of this study was to investigate the effect of two cementless femoral stem designs with different lengths on the primary stability. A finite element model of a composite Sawbones(®) fourth generation, implanted with five lengths of the straight prosthesis design and four lengths of the curved prosthesis design, was loaded with hip joint and abductor forces representing two physiological activities: fast walking and stair climbing. We found that reducing the straight stem length from 146 to 54 mm increased the average micromotion from 17 to 52 μm during fast walking, while the peak value increased from 42 to 104 μm. With the curved stem, reducing length from 105 to 54 mm increased the average micromotion from 10 to 29 μm, while the peak value increased from 37 to 101 μm. Similar findings are obtained for stair climbing for both stems. Although the present study showed that femoral stem length as well as stem design directly influences its primary stability, for the two femoral stems tested, length could be reduced substantially without compromising the primary stability. With the aim of minimising surgical invasiveness, newer femoral stem design and currently well performing stems might be used with a reduced length without compromising primary stability and hence, long-term survivorship.

In Vivo Measurement of Pediatric Vocal Fold Motion Using Structured Light Laser Projection

PubMed Central

Patel, Rita R.; Donohue, Kevin D.; Lau, Daniel; Unnikrishnan, Harikrishnan

2013-01-01

Summary Objective The aim of the study was to present the development of a miniature structured light laser projection endoscope and to quantify vocal fold length and vibratory features related to impact stress of the pediatric glottis using high-speed imaging. Study Design The custom-developed laser projection system consists of a green laser with a 4-mm diameter optics module at the tip of the endoscope, projecting 20 vertical laser lines on the glottis. Measurements of absolute phonatory vocal fold length, membranous vocal fold length, peak amplitude, amplitude-to-length ratio, average closing velocity, and impact velocity were obtained in five children (6–9 years), two adult male and three adult female participants without voice disorders, and one child (10 years) with bilateral vocal fold nodules during modal phonation. Results Independent measurements made on the glottal length of a vocal fold phantom demonstrated a 0.13 mm bias error with a standard deviation of 0.23 mm, indicating adequate precision and accuracy for measuring vocal fold structures and displacement. First, in vivo measurements of amplitude-to-length ratio, peak closing velocity, and impact velocity during phonation in pediatric population and a child with vocal fold nodules are reported. Conclusion The proposed laser projection system can be used to obtain in vivo measurements of absolute length and vibratory features in children and adults. Children have large amplitude-to-length ratio compared with typically developing adults, whereas nodules result in larger peak amplitude, amplitude-to-length ratio, average closing velocity, and impact velocity compared with typically developing children. PMID:23809569

Microscopic optical path length difference and polarization measurement system for cell analysis

NASA Astrophysics Data System (ADS)

Satake, H.; Ikeda, K.; Kowa, H.; Hoshiba, T.; Watanabe, E.

2018-03-01

In recent years, noninvasive, nonstaining, and nondestructive quantitative cell measurement techniques have become increasingly important in the medical field. These cell measurement techniques enable the quantitative analysis of living cells, and are therefore applied to various cell identification processes, such as those determining the passage number limit during cell culturing in regenerative medicine. To enable cell measurement, we developed a quantitative microscopic phase imaging system based on a Mach-Zehnder interferometer that measures the optical path length difference distribution without phase unwrapping using optical phase locking. The applicability of our phase imaging system was demonstrated by successful identification of breast cancer cells amongst normal cells. However, the cell identification method using this phase imaging system exhibited a false identification rate of approximately 7%. In this study, we implemented a polarimetric imaging system by introducing a polarimetric module to one arm of the Mach-Zehnder interferometer of our conventional phase imaging system. This module was comprised of a quarter wave plate and a rotational polarizer on the illumination side of the sample, and a linear polarizer on the optical detector side. In addition, we developed correction methods for the measurement errors of the optical path length and birefringence phase differences that arose through the influence of elements other than cells, such as the Petri dish. As the Petri dish holding the fluid specimens was transparent, it did not affect the amplitude information; however, the optical path length and birefringence phase differences were affected. Therefore, we proposed correction of the optical path length and birefringence phase for the influence of elements other than cells, as a prerequisite for obtaining highly precise phase and polarimetric images.

Cell cycle phases in the unequal mother/daughter cell cycles of Saccharomyces cerevisiae.

PubMed

Brewer, B J; Chlebowicz-Sledziewska, E; Fangman, W L

1984-11-01

During cell division in the yeast Saccharomyces cerevisiae mother cells produce buds (daughter cells) which are smaller and have longer cell cycles. We performed experiments to compare the lengths of cell cycle phases in mothers and daughters. As anticipated from earlier indirect observations, the longer cell cycle time of daughter cells is accounted for by a longer G1 interval. The S-phase and the G2-phase are of the same duration in mother and daughter cells. An analysis of five isogenic strains shows that cell cycle phase lengths are independent of cell ploidy and mating type.

Serotonergic raphe magnus cell discharge reflects ongoing autonomic and respiratory activities.

PubMed

Mason, Peggy; Gao, Keming; Genzen, Jonathan R

2007-10-01

Serotonergic cells are located in a restricted number of brain stem nuclei, send projections to virtually all parts of the CNS, and are critical to normal brain function. They discharge tonically at a rate modulated by the sleep-wake cycle and, in the case of medullary serotonergic cells in raphe magnus and the adjacent reticular formation (RM), are excited by cold challenge. Yet, beyond behavioral state and cold, endogenous factors that influence serotonergic cell discharge remain largely mysterious. The present study in the anesthetized rat investigated predictors of serotonergic RM cell discharge by testing whether cell discharge correlated to three rhythms observed in blood pressure recordings that averaged >30 min in length. A very slow frequency rhythm with a period of minutes, a respiratory rhythm, and a cardiac rhythm were derived from the blood pressure recording. Cross-correlations between each of the derived rhythms and cell activity revealed that the discharge of 38 of the 40 serotonergic cells studied was significantly correlated to the very slow and/or respiratory rhythms. Very few serotonergic cells discharged in relation to the cardiac cycle and those that did, did so weakly. The correlations between serotonergic cell discharge and the slow and respiratory rhythms cannot arise from baroreceptive input. Instead we hypothesize that they are by-products of ongoing adjustments to homeostatic functions that happen to alter blood pressure. Thus serotonergic RM cells integrate information about multiple homeostatic activities and challenges and can consequently modulate spinal processes according to the most pressing need of the organism.

Acoustic Liners for Turbine Engines

NASA Technical Reports Server (NTRS)

Jones, Michael G (Inventor); Grady, Joseph E (Inventor); Heidmann, James D. (Inventor); Kiser, James D. (Inventor); Miller, Christopher (Inventor)

2016-01-01

An improved acoustic liner for turbine engines is disclosed. The acoustic liner may include a straight cell section including a plurality of cells with straight chambers. The acoustic liner may also include a bent cell section including one or more cells that are bent to extend chamber length without increasing the overall height of the acoustic liner by the entire chamber length. In some cases, holes are placed between cell chambers in addition to bending the cells, or instead of bending the cells.

Analysis of Cell Division and Elongation Underlying the Developmental Acceleration of Root Growth in Arabidopsis thaliana1

PubMed Central

Beemster, Gerrit T.S.; Baskin, Tobias I.

1998-01-01

To investigate the relation between cell division and expansion in the regulation of organ growth rate, we used Arabidopsis thaliana primary roots grown vertically at 20°C with an elongation rate that increased steadily during the first 14 d after germination. We measured spatial profiles of longitudinal velocity and cell length and calculated parameters of cell expansion and division, including rates of local cell production (cells mm−1 h−1) and cell division (cells cell−1 h−1). Data were obtained for the root cortex and also for the two types of epidermal cell, trichoblasts and atrichoblasts. Accelerating root elongation was caused by an increasingly longer growth zone, while maximal strain rates remained unchanged. The enlargement of the growth zone and, hence, the accelerating root elongation rate, were accompanied by a nearly proportionally increased cell production. This increased production was caused by increasingly numerous dividing cells, whereas their rates of division remained approximately constant. Additionally, the spatial profile of cell division rate was essentially constant. The meristem was longer than generally assumed, extending well into the region where cells elongated rapidly. In the two epidermal cell types, meristem length and cell division rate were both very similar to that of cortical cells, and differences in cell length between the two epidermal cell types originated at the apex of the meristem. These results highlight the importance of controlling the number of dividing cells, both to generate tissues with different cell lengths and to regulate the rate of organ enlargement. PMID:9536070

A Model of Nursing Interim Care.

ERIC Educational Resources Information Center

Thienhaus, Ole J.; Greschel, Jean

In an increasingly cost-conscious health care environment, average length of hospital stay has decreased. Although psychiatric inpatient treatment is largely exempt from the constraints of the Medicare diagnosis related groups (DRG's), length of stay for geropsychiatric hospital services has decreased also. A trend toward higher rates of early…

Size uniformity of animal cells is actively maintained by a p38 MAPK-dependent regulation of G1-length.

PubMed

Liu, Shixuan; Ginzberg, Miriam Bracha; Patel, Nish; Hild, Marc; Leung, Bosco; Li, Zhengda; Chen, Yen-Chi; Chang, Nancy; Wang, Yuan; Tan, Ceryl; Diena, Shulamit; Trimble, William; Wasserman, Larry; Jenkins, Jeremy L; Kirschner, Marc W; Kafri, Ran

2018-03-29

Animal cells within a tissue typically display a striking regularity in their size. To date, the molecular mechanisms that control this uniformity are still unknown. We have previously shown that size uniformity in animal cells is promoted, in part, by size-dependent regulation of G1 length. To identify the molecular mechanisms underlying this process, we performed a large-scale small molecule screen and found that the p38 MAPK pathway is involved in coordinating cell size and cell cycle progression. Small cells display higher p38 activity and spend more time in G1 than larger cells. Inhibition of p38 MAPK leads to loss of the compensatory G1 length extension in small cells, resulting in faster proliferation, smaller cell size and increased size heterogeneity. We propose a model wherein the p38 pathway responds to changes in cell size and regulates G1 exit accordingly, to increase cell size uniformity. © 2017, Liu et al.

Morphometric analysis of the neuronal numbers and densities of the inferior olivary complex in the donkey (Equus asinus).

PubMed

Alkafafy, Mohamed; Rashed, Reda; Attia, Hossam

2011-07-01

The morphometric interrelations between the compartments of the inferior olivary complex (IOC) in the donkey (Equus asinus) were ascertained by examining serial sections throughout the entire length of the IOC for both sides. Nissl-stained celloidin sections of four brainstems of donkeys were used. The IOC consisted of three major nuclei and four small cell groups. The total neuronal count in both sides of the IOC was 202,040±8480 cells. The medial accessory olivary nucleus (MAO) had the largest relative area (46%) and the highest number of neurons (90,800±7600). The dorsal accessory olivary nucleus (DAO) had the second largest relative area (33%), while the principal olivary nucleus (PO) had the lowest relative area (21%). However, the total neuron count in the PO was larger (60,840±1840) than DAO (50,360±4040). The average neuronal density was 2700±400 cells/mm(3). The numerical values of the current study of the IOC in the donkey were similar to those of other mammals. Copyright © 2010 Elsevier GmbH. All rights reserved.

Cell Growth Characteristics, Differentiation Frequency, and Immunophenotype of Adult Ear Mesenchymal Stem Cells

PubMed Central

Staszkiewicz, Jaroslaw; Frazier, Trivia P.; Rowan, Brian G.; Bunnell, Bruce A.; Chiu, Ernest S.; Gimble, Jeffrey M.

2010-01-01

Ear mesenchymal stem cells (EMSCs) represent a readily accessible population of stem-like cells that are adherent, clonogenic, and have the ability to self-renew. Previously, we have demonstrated that they can be induced to differentiate into adipocyte, osteocyte, chondrocyte, and myocyte lineages. The purpose of the current study was to characterize the growth kinetics of the cells and to determine their ability to form colonies of fibroblasts, adipocytes, osteocytes, and chondrocytes. In addition, the immunophenotypes of freshly isolated and culture-expanded cells were evaluated. From 1 g of tissue, we were able to isolate an average of 7.8 × 106 cells exhibiting a cell cycle length of ∼2–3 days. Colony-forming unit (CFU) assays indicated high proliferation potential, and confirmed previously observed multipotentiality of the cells. Fluorescence-activated cell sorting (FACS) showed that EMSCs were negative for hematopoietic markers (CD4, CD45), proving that they did not derive from circulating hematopoietic cells. The FACS analyses also showed high expression of stem cell antigen-1 (Sca-1) with only a minor population of cells expressing CD117, thus identifying Sca-1 as the more robust stem cell biomarker. Additionally, flow cytometry data revealed that the expression patterns of hematopoietic, stromal, and stem cell markers were maintained in the passaged EMSCs, consistent with the persistence of an undifferentiated state. This study indicates that EMSCs provide an alternative model for in vitro analyses of adult mesenchymal stem cells (MSCs). Further studies will be necessary to determine their utility for tissue engineering and regenerative medical applications. PMID:19400629

Automatic cell identification and visualization using digital holographic microscopy with head mounted augmented reality devices.

PubMed

O'Connor, Timothy; Rawat, Siddharth; Markman, Adam; Javidi, Bahram

2018-03-01

We propose a compact imaging system that integrates an augmented reality head mounted device with digital holographic microscopy for automated cell identification and visualization. A shearing interferometer is used to produce holograms of biological cells, which are recorded using customized smart glasses containing an external camera. After image acquisition, segmentation is performed to isolate regions of interest containing biological cells in the field-of-view, followed by digital reconstruction of the cells, which is used to generate a three-dimensional (3D) pseudocolor optical path length profile. Morphological features are extracted from the cell's optical path length map, including mean optical path length, coefficient of variation, optical volume, projected area, projected area to optical volume ratio, cell skewness, and cell kurtosis. Classification is performed using the random forest classifier, support vector machines, and K-nearest neighbor, and the results are compared. Finally, the augmented reality device displays the cell's pseudocolor 3D rendering of its optical path length profile, extracted features, and the identified cell's type or class. The proposed system could allow a healthcare worker to quickly visualize cells using augmented reality smart glasses and extract the relevant information for rapid diagnosis. To the best of our knowledge, this is the first report on the integration of digital holographic microscopy with augmented reality devices for automated cell identification and visualization.

Hot-spot heating in central-station arrays

NASA Technical Reports Server (NTRS)

Gonzalez, C. C.

1983-01-01

Hot spot tests performed on the Sacramento Municipal Utility District (SMUD) verificaton array show that current imbalance occurs, resulting in significant hot spot heating. One cause of current imbalance is differences in the average shunt resistances of parallel cell strings due to cell shunt resistance variations. In depth hot spot tests are performed on the verification array with bypass diodes. The tests had several objectives: (1) a comparison of hot spot temperatures achieved under field conditions with those obtained with the present laboratory hot spot test using similar modules; (2) an assessment of current imbalance versus cross tie frequency; and (3) an assessment of different shadow patterns and shadow densities. Instrumented modules are used to vary the number of cross ties and to measure the test-cell current and back-bias voltage. The widths, lengths, and densities of the shadows are varied to maximize the back bias voltage at maximum power current. An infrared camera is used to indicate the existence of hot spots and estimate temperature increases in conjunction with thermocouples. The results of these hot spot tests indicate a sensitivity of back bias heating to the shadow size (amount of cell coverage) and density.

Model for threading dislocations in metamorphic tandem solar cells on GaAs (001) substrates

NASA Astrophysics Data System (ADS)

Song, Yifei; Kujofsa, Tedi; Ayers, John E.

2018-02-01

We present an approximate model for the threading dislocations in III-V heterostructures and have applied this model to study the defect behavior in metamorphic triple-junction solar cells. This model represents a new approach in which the coefficient for second-order threading dislocation annihilation and coalescence reactions is considered to be determined by the length of misfit dislocations, LMD, in the structure, and we therefore refer to it as the LMD model. On the basis of this model we have compared the average threading dislocation densities in the active layers of triple junction solar cells using linearly-graded buffers of varying thicknesses as well as S-graded (complementary error function) buffers with varying thicknesses and standard deviation parameters. We have shown that the threading dislocation densities in the active regions of metamorphic tandem solar cells depend not only on the thicknesses of the buffer layers but on their compositional grading profiles. The use of S-graded buffer layers instead of linear buffers resulted in lower threading dislocation densities. Moreover, the threading dislocation densities depended strongly on the standard deviation parameters used in the S-graded buffers, with smaller values providing lower threading dislocation densities.

Physical Models of Layered Polar Firn Brightness Temperatures from 0.5 to 2 GHz

NASA Technical Reports Server (NTRS)

Tan, Shurun; Aksoy, Mustafa; Brogioni, Marco; Macelloni, Giovanni; Durand, Michael; Jezek, Kenneth C.; Wang, Tian-Lin; Tsang, Leung; Johnson, Joel T.; Drinkwater, Mark R.;

Mechanisms limiting the performance of large grain polycrystalline silicon solar cells

NASA Technical Reports Server (NTRS)

Culik, J. S.; Alexander, P.; Dumas, K. A.; Wohlgemuth, J. W.

1984-01-01

The open-circuit voltage and short-circuit current of large-grain (1 to 10 mm grain diameter) polycrystalline silicon solar cells is determined by the minority-carrier diffusion length within the bulk of the grains. This was demonstrated by irradiating polycrystalline and single-crystal (Czochralski) silicon solar cells with 1 MeV electrons to reduce their bulk lifetime. The variation of short-circuit current with minority-carrier diffusion length for the polycrystalline solar cells is identical to that of the single-crystal solar cells. The open-circuit voltage versus short-circuit current characteristic of the polycrystalline solar cells for reduced diffusion lengths is also identical to that of the single-crystal solar cells. The open-circuit voltage of the polycrystalline solar cells is a strong function of quasi-neutral (bulk) recombination, and is reduced only slightly, if at all, by grain-boundary recombination.

Recovery of infectious classical swine fever virus (CSFV) from full-length genomic cDNA clones by a swine kidney cell line expressing bacteriophage T7 RNA polymerase.

PubMed

van Gennip, H G; van Rijn, P A; Widjojoatmodjo, M N; Moormann, R J

1999-03-01

A new method for the recovery of infectious classical swine fever virus (CSFV) from full-length genomic cDNA clones of the C-strain was developed. Classical reverse genetics is based on transfection of in vitro transcribed RNA to target cells to recover RNA viruses. However, the specific infectivity of such in vitro transcribed RNA in swine kidney cells is usually low. To improve reverse genetics for CSFV, a stable swine kidney cell line was established that expresses cytoplasmic bacteriophage T7 RNA polymerase (SK6.T7). A 200-fold increased virus titre was obtained from SK6.T7 cells transfected with linearized full-length cDNA compared to in vitro transcribed RNA, whereas transfection of circular full-length cDNA resulted in 20-fold increased virus titres. Viruses generated on the SK6.T7 cells are indistinguishable from the viruses generated by the classical reverse genetic procedures. These results show the improved recovery of infectious CSFV directly from full-length cDNAs. Furthermore, the reverse genetic procedures are simplified to a faster, one step protocol. We conclude that the SK6.T7 cell line will be a valuable tool for recovering mutant CSFV and will contribute to future pestivirus research.

Quantifying wall turbulence via a symmetry approach: A Lie group theory

NASA Astrophysics Data System (ADS)

She, Zhen-Su; Chen, Xi; Hussain, Fazle

2017-11-01

We present a symmetry-based approach which yields analytic expressions for the mean velocity and kinetic energy profiles from a Lie-group analysis. After verifying the dilation-group invariance of the Reynolds averaged Navier-Stokes equation in the presence of a wall, we select a stress and energy length function as similarity variables which are assumed to have a simple dilation-invariant form. Three kinds of (local) invariant forms of the length functions are postulated, a combination of which yields a multi-layer formula giving its distribution in the entire flow region normal to the wall. The mean velocity profile is then predicted using the mean momentum equation, which yields, in particular, analytic expressions for the (universal) wall function and separate wake functions for pipe and channel - which are validated by data from direct numerical simulations (DNS). Future applications to a variety of wall flows such as flows around flat plate or airfoil, in a Rayleigh-Benard cell or Taylor-Couette system, etc., are discussed, for which the dilation group invariance is valid in the wall-normal direction.

Cutting work in thick section cryomicrotomy.

PubMed

Saubermann, A J; Riley, W D; Beeuwkes, R

1977-09-01

The forces during cryosectioning were measured using miniature strain gauges attached to a load cell fitted to the drive arm of the Porter-Blum MT-2 cryomicrotome. Work was calculated and the data normalized to a standard (1 mm X 1 mm X 0.5 micrometer) section. Thermal energy generated was also calculated. Five parameters were studied: cutting angle, thickness, temperature, hardness, and block shape. Force patterns could be divided into three major groups thought to represent cutting (Type I), large fracture planes greater than 10 micrometer in length (Type II), and small fracture planes less than 10 micrometer in length (Type III). Type I and Type II produced satisfactory sections. Work in cutting ranged from an average of 78.4 muJ to 568.8 muJ. Cutting angle and temperature had the greatest effect on sectioning. Heat generated would be sufficient to cause through-section melting for 0.5 micrometer thick sections assuming the worst possible case, namely that all heat went into the section without loss. Presence of a Type II pattern (large fracture pattern) is thought to be presumptive evidence against thawing.

Effects of acidity on tree pollen germination and tube growth

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

Jacobson, J.S.; Van Rye, D.M.; Lassoie, J.P.

Several studies have indicated that pollen germination and tube growth are adversely affected by air pollutants. Pollutants may inhibit the function of pollen by reducing the number of pollen grains which germinate, by reducing the maximum length to which the pollen tubes grow, or by interfering with the formation of the generative cell. The paper reports on studies that are attempting to determine the effects acid rain may have on these crucial stages in the life histories of northeastern tree species. The first stage of this work assessed the effects of acidity in the growth medium on in vitro pollenmore » germination for four deciduous forest species common to central New York State, Betula lutea (yellow birch), B. lenta (black birch), Acer saccharum (sugar maple), and Cornus florida (flowering dogwood). Measurements were taken at the end of the growth period to determine the percentage of grains which had germinated, and to estimate the average tube length. To determine the effects of pollen on the growth medium, the pH of the germination drop was measured at the end of the growth period.« less

Factors Influencing the Production of MFSV Full-Length Clone: Maize Fine Streak Virus Proteins in Drosophila S2 Cells

USDA-ARS?s Scientific Manuscript database

Maize fine streak virus (MFSV) is negative-sense RNA virus member of the genus Nucleorhabdovirus. Our goal is to determine whether Drosophila S2 cells can support the production of a full-length clone of MFSV. We have previously demonstrated that the full-length MFSV nucleoprotein (N) and phosphopro...

Intrinsic curvature in wool fibres is determined by the relative length of orthocortical and paracortical cells.

PubMed

Harland, Duane P; Vernon, James A; Woods, Joy L; Nagase, Shinobu; Itou, Takashi; Koike, Kenzo; Scobie, David A; Grosvenor, Anita J; Dyer, Jolon M; Clerens, Stefan

2018-03-22

Hair curvature underpins structural diversity and function in mammalian coats, but what causes curl in keratin hair fibres? To obtain structural data to determine one aspect of this question, we used confocal microscopy to provide in situ measurements of the two cell types that make up the cortex of merino wool fibres, which was chosen as a well-characterised model system representative of narrow diameter hairs, such as underhairs. We measured orthocortical and paracortical cross-sectional areas, and cortical cell lengths, within individual fibre snippets of defined uniplanar curvature. This allowed a direct test of two long-standing theories of the mechanism of curvature in hairs. We found evidence contradicting the theory that curvature results from there being more cells on the side of the fibre closest to the outside, or convex edge, of curvature. In all cases, the orthocortical cells close to the outside of curvature were longer than paracortical cells close to the inside of the curvature, which supports the theory that curvature is underpinned by differences in cell type length. However, the latter theory also implies that, for all fibres, curvature should correlate with the proportions of orthocortical and paracortical cells, and we found no evidence for this. In merino wool, it appears that the absolute length of cells of each type and proportion of cells varies from fibre to fibre, and only the difference between the length of the two cell types is important. Implications for curvature in higher diameter hairs, such as guard hairs and those on the human scalp, are discussed. © 2018. Published by The Company of Biologists Ltd.

Physical activity and telomere length: Impact of aging and potential mechanisms of action

PubMed Central

Arsenis, Nicole C.; You, Tongjian; Ogawa, Elisa F.; Tinsley, Grant M.; Zuo, Li

2017-01-01

Telomeres protect the integrity of information-carrying DNA by serving as caps on the terminal portions of chromosomes. Telomere length decreases with aging, and this contributes to cell senescence. Recent evidence supports that telomere length of leukocytes and skeletal muscle cells may be positively associated with healthy living and inversely correlated with the risk of several age-related diseases, including cancer, cardiovascular disease, obesity, diabetes, chronic pain, and stress. In observational studies, higher levels of physical activity or exercise are related to longer telomere lengths in various populations, and athletes tend to have longer telomere lengths than non-athletes. This relationship is particularly evident in older individuals, suggesting a role of physical activity in combating the typical age-induced decrements in telomere length. To date, a small number of exercise interventions have been executed to examine the potential influence of chronic exercise on telomere length, but these studies have not fully established such relationship. Several potential mechanisms through which physical activity or exercise could affect telomere length are discussed, including changes in telomerase activity, oxidative stress, inflammation, and decreased skeletal muscle satellite cell content. Future research is needed to mechanistically examine the effects of various modalities of exercise on telomere length in middle-aged and older adults, as well as in specific clinical populations. PMID:28410238

Physical activity and telomere length: Impact of aging and potential mechanisms of action.

PubMed

Arsenis, Nicole C; You, Tongjian; Ogawa, Elisa F; Tinsley, Grant M; Zuo, Li

2017-07-04

Telomeres protect the integrity of information-carrying DNA by serving as caps on the terminal portions of chromosomes. Telomere length decreases with aging, and this contributes to cell senescence. Recent evidence supports that telomere length of leukocytes and skeletal muscle cells may be positively associated with healthy living and inversely correlated with the risk of several age-related diseases, including cancer, cardiovascular disease, obesity, diabetes, chronic pain, and stress. In observational studies, higher levels of physical activity or exercise are related to longer telomere lengths in various populations, and athletes tend to have longer telomere lengths than non-athletes. This relationship is particularly evident in older individuals, suggesting a role of physical activity in combating the typical age-induced decrements in telomere length. To date, a small number of exercise interventions have been executed to examine the potential influence of chronic exercise on telomere length, but these studies have not fully established such relationship. Several potential mechanisms through which physical activity or exercise could affect telomere length are discussed, including changes in telomerase activity, oxidative stress, inflammation, and decreased skeletal muscle satellite cell content. Future research is needed to mechanistically examine the effects of various modalities of exercise on telomere length in middle-aged and older adults, as well as in specific clinical populations.

Karyotype variation in cultivars and spontaneous cocoa mutants (Theobroma cacao L.).

PubMed

Figueiredo, G S F; Melo, C A F; Souza, M M; Araújo, I S; Zaidan, H A; Pires, J L; Ahnert, D

2013-10-18

Four mutant cocoa accessions with morphological changes and a cultivar sample were karyomorphologically characterized. Slides were prepared by enzymatic digestion of the root meristem and squashed in 45% acetic acid, followed by 2% Giemsa staining. The chromosome number of 2n = 20 was seen in all accessions. The karyotype formula for Cacau Comum and Cacau Rui was 2n = 20m. Submetacentric chromosomes were observed in Cacau Pucala and Cacau Jaca, both with 2n = 18m + 2sm, but the karyotype formula for Cacau Sem Vidro was 2n = 16m + 4sm. Satellites were located on the long arm of the 1st and 2nd chromosome pairs of Cacau Comum, whereas Cacau Pucala had satellites on the 6th chromosome pair. Greater karyotypic variation in Cacau Sem Vidro was found, whose 1st and 2nd chromosome pairs had satellites on the long arm and 6th and 10th pairs had satellites on the short arm. Analysis revealed a lower average chromosome length in Cacau Comum (1.53 ± 0.026 µm) and a higher length in Cacau Sem Vidro (2.26 ± 0.038 µm). ANOVA revealed significant difference (P < 0.01) for the average chromosome length and the length of chromosome pairs within and between accessions. The average chromosome lengths of mutants of Cacau Rui and Cacau Jaca were not statistically different by the Tukey test at 5% probability. The karyotypic diversity observed in this study is not necessarily associated with the changing character of the accessions analyzed, but may reflect the genetic variation observed in Theobroma cacao.

Abelson tyrosine-protein kinase 2 regulates myoblast proliferation and controls muscle fiber length

PubMed Central

Lee, Jennifer K; Hallock, Peter T

2017-01-01

Muscle fiber length is nearly uniform within a muscle but widely different among different muscles. We show that Abelson tyrosine-protein kinase 2 (Abl2) has a key role in regulating myofiber length, as a loss of Abl2 leads to excessively long myofibers in the diaphragm, intercostal and levator auris muscles but not limb muscles. Increased myofiber length is caused by enhanced myoblast proliferation, expanding the pool of myoblasts and leading to increased myoblast fusion. Abl2 acts in myoblasts, but as a consequence of expansion of the diaphragm muscle, the diaphragm central tendon is reduced in size, likely contributing to reduced stamina of Abl2 mutant mice. Ectopic muscle islands, each composed of myofibers of uniform length and orientation, form within the central tendon of Abl2+/− mice. Specialized tendon cells, resembling tendon cells at myotendinous junctions, form at the ends of these muscle islands, suggesting that myofibers induce differentiation of tendon cells, which reciprocally regulate myofiber length and orientation. PMID:29231808

Abelson tyrosine-protein kinase 2 regulates myoblast proliferation and controls muscle fiber length.

PubMed

Lee, Jennifer K; Hallock, Peter T; Burden, Steven J

2017-12-12

Muscle fiber length is nearly uniform within a muscle but widely different among different muscles. We show that Abelson tyrosine-protein kinase 2 (Abl2) has a key role in regulating myofiber length, as a loss of Abl2 leads to excessively long myofibers in the diaphragm, intercostal and levator auris muscles but not limb muscles. Increased myofiber length is caused by enhanced myoblast proliferation, expanding the pool of myoblasts and leading to increased myoblast fusion. Abl2 acts in myoblasts, but as a consequence of expansion of the diaphragm muscle, the diaphragm central tendon is reduced in size, likely contributing to reduced stamina of Abl2 mutant mice. Ectopic muscle islands, each composed of myofibers of uniform length and orientation, form within the central tendon of Abl2 +/- mice. Specialized tendon cells, resembling tendon cells at myotendinous junctions, form at the ends of these muscle islands, suggesting that myofibers induce differentiation of tendon cells, which reciprocally regulate myofiber length and orientation.

Streamwise Versus Spanwise Spacing of Obstacle Arrays: Parametrization of the Effects on Drag and Turbulence

NASA Astrophysics Data System (ADS)

Simón-Moral, Andres; Santiago, Jose Luis; Krayenhoff, E. Scott; Martilli, Alberto

2014-06-01

A Reynolds-averaged Navier-Stokes model is used to investigate the evolution of the sectional drag coefficient and turbulent length scales with the layouts of aligned arrays of cubes. Results show that the sectional drag coefficient is determined by the non-dimensional streamwise distance (sheltering parameter), and the non-dimensional spanwise distance (channelling parameter) between obstacles. This is different than previous approaches that consider only plan area density . On the other hand, turbulent length scales behave similarly to the staggered case (e. g. they are function of only). Analytical formulae are proposed for the length scales and for the sectional drag coefficient as a function of sheltering and channelling parameters, and implemented in a column model. This approach demonstrates good skill in the prediction of vertical profiles of the spatially-averaged horizontal wind speed.

The effect of maternal substance abuse on the cost of neonatal care.

PubMed

Norton, E C; Zarkin, G A; Calingaert, B; Bradley, C J

1996-01-01

This study addresses the effect of maternal substance abuse on the cost of neonatal care in a sample of all singleton live births in Maryland in 1991. Most other cost studies have analyzed data from only one hospital; we analyzed data from 54 hospitals and therefore can control for individual hospital effects and correlation of observations within hospitals. We find that maternal drug abuse has a significant positive effect on total hospital charges, length of stay, and average daily charges, with the increase in length of stay being proportionally greater than the increase in average daily charges. Maternal alcohol abuse also has a positive effect on hospital charges and length of stay, but the effects are not statistically significant. About half the effect of drug abuse on total charges works indirectly through premature birth and other comorbidities.

Diagnostic classification of macular ganglion cell and retinal nerve fiber layer analysis: differentiation of false-positives from glaucoma.

PubMed

Kim, Ko Eun; Jeoung, Jin Wook; Park, Ki Ho; Kim, Dong Myung; Kim, Seok Hwan

2015-03-01

To investigate the rate and associated factors of false-positive diagnostic classification of ganglion cell analysis (GCA) and retinal nerve fiber layer (RNFL) maps, and characteristic false-positive patterns on optical coherence tomography (OCT) deviation maps. Prospective, cross-sectional study. A total of 104 healthy eyes of 104 normal participants. All participants underwent peripapillary and macular spectral-domain (Cirrus-HD, Carl Zeiss Meditec Inc, Dublin, CA) OCT scans. False-positive diagnostic classification was defined as yellow or red color-coded areas for GCA and RNFL maps. Univariate and multivariate logistic regression analyses were used to determine associated factors. Eyes with abnormal OCT deviation maps were categorized on the basis of the shape and location of abnormal color-coded area. Differences in clinical characteristics among the subgroups were compared. (1) The rate and associated factors of false-positive OCT maps; (2) patterns of false-positive, color-coded areas on the GCA deviation map and associated clinical characteristics. Of the 104 healthy eyes, 42 (40.4%) and 32 (30.8%) showed abnormal diagnostic classifications on any of the GCA and RNFL maps, respectively. Multivariate analysis revealed that false-positive GCA diagnostic classification was associated with longer axial length and larger fovea-disc angle, whereas longer axial length and smaller disc area were associated with abnormal RNFL maps. Eyes with abnormal GCA deviation map were categorized as group A (donut-shaped round area around the inner annulus), group B (island-like isolated area), and group C (diffuse, circular area with an irregular inner margin in either). The axial length showed a significant increasing trend from group A to C (P=0.001), and likewise, the refractive error was more myopic in group C than in groups A (P=0.015) and B (P=0.014). Group C had thinner average ganglion cell-inner plexiform layer thickness compared with other groups (group A=B>C, P=0.004). Abnormal OCT diagnostic classification should be interpreted with caution, especially in eyes with long axial lengths, large fovea-disc angles, and small optic discs. Our findings suggest that the characteristic patterns of OCT deviation map can provide useful clues to distinguish glaucomatous changes from false-positive findings. Copyright © 2015 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

Dielectric aggregation kinetics of cells in a uniform AC electric field.

PubMed

Tada, Shigeru; Natsuya, Tomoyuki; Tsukamoto, Akira

2014-01-01

Cell manipulation and separation technologies have potential biological and medical applications, including advanced clinical protocols such as tissue engineering. An aggregation model was developed for a human carcinoma (HeLa) cell suspension exposed to a uniform AC electric field, in order to explore the field-induced structure formation and kinetics of cell aggregates. The momentum equations of cells under the action of the dipole-dipole interaction were solved theoretically and the total time required to form linear string-like cluster was derived. The results were compared with those of a numerical simulation. Experiments using HeLa cells were also performed for comparison. The total time required to form linear string-like clusters was derived from a simple theoretical model of the cell cluster kinetics. The growth rates of the average string length of cell aggregates showed good agreement with those of the numerical simulation. In the experiment, cells were found to form massive clusters on the bottom of a chamber. The results imply that the string-like cluster grows rapidly by longitudinal attraction when the electric field is first applied and that this process slows at later times and is replaced by lateral coagulation of short strings. The findings presented here are expected to enable design of methods for the organization of three-dimensional (3D) cellular structures without the use of micro-fabricated substrates, such as 3D biopolymer scaffolds, to manipulate cells into spatial arrangement.

Study of lung-metastasized prostate cancer cell line chemotaxis to epidermal growth factor with a BIOMEMS device

NASA Astrophysics Data System (ADS)

Tata, Uday; Rao, Smitha M. N.; Sharma, Akash; Pabba, Krishna; Pokhrel, Kushal; Adhikari, Bandita; Lin, Victor K.; Chiao, J.-C.

2012-09-01

Understanding the effects of different growth factors on cancer metastasis will enable researchers to develop effective post-surgery therapeutic strategies to stop the spread of cancer. Conventional Boyden chamber assays to evaluate cell motility in metastasis studies require high volumes of reagents and are impractical for high-throughput analysis. A microfluidic device was designed for arrayed assaying of prostate cancer cell migration towards different growth factors. The device was created with polydimethylsiloxane (PDMS) and featured two wells connected by 10 micro channels. One well was for cell seeding and the other well for specific growth factors. Each channel has a width of 20 μm, a length of 1 mm and a depth of 10 μm. The device was placed on a culture dish and primed with growth media. Lung-metastasized cells in suspension of RPMI 1640 media1 supplemented with 2% of fetal bovine serum (FBS) were seeded in the cell wells. Cell culture media with epidermal growth factor (EGF) of 25, 50, 75, 100 and 125 ng ml-1 concentrations were individually added in the respective growth factor wells. A 5-day time-lapsed study of cell migration towards the chemoattractant was performed. The average numbers of cells per device in the microchannels were obtained for each attractant condition. The results indicated migration of cells increased from 50 to 100 ng ml-1 of EGF and significantly decreased at 125 ng ml-1 of EGF, as compared to control.

Three-dimensional architecture of the whole human soleus muscle in vivo

PubMed Central

Finni, Taija; D’Souza, Arkiev; Eguchi, Junya; Clarke, Elizabeth C.; Herbert, Robert D.

2018-01-01

Background Most data on the architecture of the human soleus muscle have been obtained from cadaveric dissection or two-dimensional ultrasound imaging. We present the first comprehensive, quantitative study on the three-dimensional anatomy of the human soleus muscle in vivo using diffusion tensor imaging (DTI) techniques. Methods We report three-dimensional fascicle lengths, pennation angles, fascicle curvatures, physiological cross-sectional areas and volumes in four compartments of the soleus at ankle joint angles of 69 ± 12° (plantarflexion, short muscle length; average ± SD across subjects) and 108 ± 7° (dorsiflexion, long muscle length) of six healthy young adults. Microdissection and three-dimensional digitisation on two cadaveric muscles corroborated the compartmentalised structure of the soleus, and confirmed the validity of DTI-based muscle fascicle reconstructions. Results The posterior compartments of the soleus comprised 80 ± 5% of the total muscle volume (356 ± 58 cm3). At the short muscle length, the average fascicle length, pennation angle and curvature was 37 ± 8 mm, 31 ± 3° and 17 ± 4 /m, respectively. We did not find differences in fascicle lengths between compartments. However, pennation angles were on average 12° larger (p < 0.01) in the posterior compartments than in the anterior compartments. For every centimetre that the muscle-tendon unit lengthened, fascicle lengths increased by 3.7 ± 0.8 mm, pennation angles decreased by −3.2 ± 0.9° and curvatures decreased by −2.7 ± 0.8 /m. Fascicles in the posterior compartments rotated almost twice as much as in the anterior compartments during passive lengthening. Discussion The homogeneity in fascicle lengths and inhomogeneity in pennation angles of the soleus may indicate a functionally different role for the anterior and posterior compartments. The data and techniques presented here demonstrate how DTI can be used to obtain detailed, quantitative measurements of the anatomy of complex skeletal muscles in living humans. PMID:29682414

Tired telomeres: Poor global sleep quality, perceived stress, and telomere length in immune cell subsets in obese men and women.

PubMed

Prather, Aric A; Gurfein, Blake; Moran, Patricia; Daubenmier, Jennifer; Acree, Michael; Bacchetti, Peter; Sinclair, Elizabeth; Lin, Jue; Blackburn, Elizabeth; Hecht, Frederick M; Epel, Elissa S

2015-07-01

Poor sleep quality and short sleep duration are associated with increased incidence and progression of a number of chronic health conditions observed at greater frequency among the obese and those experiencing high levels of stress. Accelerated cellular aging, as indexed by telomere attrition in immune cells, is a plausible pathway linking sleep and disease risk. Prior studies linking sleep and telomere length are mixed. One factor may be reliance on leukocytes, which are composed of varied immune cell types, as the sole measure of telomere length. To better clarify these associations, we investigated the relationships of global sleep quality, measured by the Pittsburgh Sleep Quality Index (PSQI), and diary-reported sleep duration with telomere length in different immune cell subsets, including granulocytes, peripheral blood mononuclear cells (PBMCs), CD8+ and CD4+ T lymphocytes, and B lymphocytes in a sample of 87 obese men and women (BMI mean=35.4, SD=3.6; 81.6% women; 62.8% Caucasian). Multiple linear regression analyses were performed adjusting for age, gender, race, education, BMI, sleep apnea risk, and perceived stress. Poorer PSQI global sleep quality was associated with statistically significantly shorter telomere length in lymphocytes but not granulocytes and in particular CD8+ T cells (b=-56.8 base pairs per one point increase in PSQI, SE=20.4, p=0.007) and CD4+ T cells (b=-37.2, SE=15.9, p=0.022). Among separate aspects of global sleep quality, low perceived sleep quality and decrements in daytime function were most related to shorter telomeres. In addition, perceived stress moderated the sleep-CD8+ telomere association. Poorer global sleep quality predicted shorter telomere length in CD8+ T cells among those with high perceived stress but not in low stress participants. These findings provide preliminary evidence that poorer global sleep quality is related to telomere length in several immune cell types, which may serve as a pathway linking sleep and disease risk in obese individuals. Copyright © 2014 Elsevier Inc. All rights reserved.

Genotoxicity assessment of raw and treated water samples using Allium cepa assay: evidence from Perak River, Malaysia.

PubMed

Malakahmad, Amirhossein; Manan, Teh Sabariah Binti Abd; Sivapalan, Subarna; Khan, Taimur

2018-02-01

Allium cepa assay was carried out in this study to evaluate genotoxic effects of raw and treated water samples from Perak River in Perak state, Malaysia. Samples were collected from three surface water treatment plants along the river, namely WTPP, WTPS, and WTPK. Initially, triplicates of equal size Allium cepa (onions) bulbs, 25-30 mm in diameter and average weight of 20 g, were set up in distilled water for 24 h at 20 ± 2 °C and protected from direct sunlight, to let the roots to grow. After germination of roots (0.5-1.0 cm in length), bulbs were transferred to collected water samples each for a 96-h period of exposure. The root physical deformations were observed. Genotoxicity quantification was based on mitotic index and genotoxicity level. Statistical analysis using cross-correlation function for replicates from treated water showed that root length has inverse correlation with mitotic indices (r = - 0.969) and frequencies of cell aberrations (r = - 0.976) at lag 1. Mitotic indices and cell aberrations of replicates from raw water have shown positive correlation at lag 1 (r = 0.946). Genotoxicity levels obtained were 23.4 ± 1.98 (WTPP), 26.68 ± 0.34 (WTPS), and 30.4 ± 1.13 (WTPK) for treated water and 17.8 ± 0.18 (WTPP), 37.15 ± 0.17 (WTPS), and 47.2 ± 0.48 (WTPK) for raw water. The observed cell aberrations were adherence, chromosome delay, C-metaphase, chromosome loss, chromosome bridge, chromosome breaks, binucleated cell, mini cell, and lobulated nuclei. The morphogenetic deformations obtained were likely due to genotoxic substances presence in collected water samples. Thus, water treatment in Malaysia does not remove genotoxic compounds.

A potential individual cell malignancy indicator: focal length

NASA Astrophysics Data System (ADS)

Wang, Weina; Lear, Kevin L.

2011-03-01

The label-free technique of optofluidic intracavity spectroscopy (OFIS) utilizes the optical transmission spectrum of a cell in a microfluidic Fabry-Pérot (F-P) cavity to distinguish cells from cancerous cell lines and baseline normal blood cells. The classification between canine hemangiosarcoma (HSA) cancer cells and monocytes in canine normal peripheral blood mononuclear cells (PBMCs) had been demonstrated with 95% sensitivity and 98% specificity. Now with a new optical model that treats the cell settled at the bottom of the cavity as a thin lens, the focal length of cells was extracted and used as an individual cell malignancy indicator.

Biologically synthesized silver nanoparticles induce neuronal differentiation of SH-SY5Y cells via modulation of reactive oxygen species, phosphatases, and kinase signaling pathways.

PubMed

Dayem, Ahmed Abdal; Kim, BongWoo; Gurunathan, Sangiliyandi; Choi, Hye Yeon; Yang, Gwangmo; Saha, Subbroto Kumar; Han, Dawoon; Han, Jihae; Kim, Kyeongseok; Kim, Jin-Hoi; Cho, Ssang-Goo

2014-07-01

Nano-scale materials are noted for unique properties, distinct from those of their bulk material equivalents. In this study, we prepared spherical silver nanoparticles (AgNPs) with an average size of about 30 nm and tested their potency to induce neuronal differentiation of SH-SY5Y cells. Human neuroblastoma SH-SY5Y cells are considered an ideal in vitro model for studying neurogenesis, as they can be maintained in an undifferentiated state or be induced to differentiate into neuron-like phenotypes in vitro by several differentiation-inducing agents. Treatment of SH-SY5Y cells by biologically synthesized AgNPs led to cell morphological changes and significant increase in neurite length and enhanced the expression of neuronal differentiation markers such as Map-2, β-tubulin III, synaptophysin, neurogenin-1, Gap-43, and Drd-2. Furthermore, we observed an increase in generation of intracellular reactive oxygen species (ROS), activation of several kinases such as ERK and AKT, and downregulation of expression of dual-specificity phosphatases (DUSPs) in AgNPs-exposed SH-SY5Y cells. Our results suggest that AgNPs modulate the intracellular signaling pathways, leading to neuronal differentiation, and could be applied as promising nanomaterials for stem cell research and therapy. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Scheme for Text Analysis Using Fortran.

ERIC Educational Resources Information Center

Koether, Mary E.; Coke, Esther U.

Using string-manipulation algorithms, FORTRAN computer programs were designed for analysis of written material. The programs measure length of a text and its complexity in terms of the average length of words and sentences, map the occurrences of keywords or phrases, calculate word frequency distribution and certain indicators of style. Trials of…

ELECTRICAL AEROSOL DETECTOR (EAD) MEASUREMENTS AT THE ST. LOUIS SUPERSITE

EPA Science Inventory

The Model 3070A Electrical Aerosol Detector (EAD) measures a unique aerosol parameter called total aerosol length. Reported as mm/cm3, aerosol length can be thought of as a number concentration times average diameter, or simply as d1 weighting. This measurement falls between nu...

50 CFR 216.175 - Requirements for monitoring and reporting.

Code of Federal Regulations, 2011 CFR

2011-10-01

...., FFG, DDG, or CG). (G) Length of time observers maintained visual contact with marine mammal. (H) Wave... height in feet (high, low and average during exercise). (I) Narrative description of sensors and... sensor. (F) Length of time observers maintained visual contact with marine mammal. (G) Wave height. (H...

5 CFR 831.703 - Computation of annuities for part-time service.

Code of Federal Regulations, 2011 CFR

2011-01-01

... during those periods of creditable service. Pre-April 7, 1986, average pay means the largest annual rate..., 1986, service is computed in accordance with 5 U.S.C. 8339 using the pre-April 7, 1986, average pay and... computed in accordance with 5 U.S.C. 8339 using the post-April 6, 1986, average pay and length of service...

Most suitable mother wavelet for the analysis of fractal properties of stride interval time series via the average wavelet coefficient

PubMed Central

Zhang, Zhenwei; VanSwearingen, Jessie; Brach, Jennifer S.; Perera, Subashan

2016-01-01

Human gait is a complex interaction of many nonlinear systems and stride intervals exhibit self-similarity over long time scales that can be modeled as a fractal process. The scaling exponent represents the fractal degree and can be interpreted as a biomarker of relative diseases. The previous study showed that the average wavelet method provides the most accurate results to estimate this scaling exponent when applied to stride interval time series. The purpose of this paper is to determine the most suitable mother wavelet for the average wavelet method. This paper presents a comparative numerical analysis of sixteen mother wavelets using simulated and real fractal signals. Simulated fractal signals were generated under varying signal lengths and scaling exponents that indicate a range of physiologically conceivable fractal signals. The five candidates were chosen due to their good performance on the mean square error test for both short and long signals. Next, we comparatively analyzed these five mother wavelets for physiologically relevant stride time series lengths. Our analysis showed that the symlet 2 mother wavelet provides a low mean square error and low variance for long time intervals and relatively low errors for short signal lengths. It can be considered as the most suitable mother function without the burden of considering the signal length. PMID:27960102

Processing of semen by density gradient centrifugation selects spermatozoa with longer telomeres for assisted reproduction techniques.

PubMed

Yang, Qingling; Zhang, Nan; Zhao, Feifei; Zhao, Wanli; Dai, Shanjun; Liu, Jinhao; Bukhari, Ihtisham; Xin, Hang; Niu, Wenbing; Sun, Yingpu

2015-07-01

The ends of eukaryotic chromosomes contain specialized chromatin structures called telomeres, the length of which plays a key role in early human embryonic development. Although the effect of sperm preparation techniques on major sperm characteristics, such as concentration, motility and morphology have been previously documented, the possible status of telomere length and its relation with sperm preparation techniques is not well-known for humans. The aim of this study was to investigate the role of density gradient centrifugation in the selection of spermatozoa with longer telomeres for use in assisted reproduction techniques in 105 samples before and after sperm processing. After density gradient centrifugation, the average telomere length of the sperm was significantly longer (6.51 ± 2.54 versus 5.16 ± 2.29, P < 0.01), the average motile sperm rate was significantly higher (77.9 ± 11.8 versus 44.6 ± 11.2, P < 0.01), but average DNA fragmentation rate was significantly lower (11.1 ± 5.9 versus 25.9 ± 12.9, P < 0.01) compared with raw semen. Additionally, telomere length was positively correlated with semen sperm count (rs = 0.58; P < 0.01). In conclusion, density gradient centrifugation is a useful technique for selection of sperm with longer telomeres. Copyright © 2015 Reproductive Healthcare Ltd. Published by Elsevier Ltd. All rights reserved.

Turbulent Premixed Hydrogen/Air Flames.

DTIC Science & Technology

1991-02-15

velocity components i K Kolmogorov scale LC flame length based on a time-averaged unreactedness of 0.5 O-/(0 2 +N2) volumetric fraction of 02 in nonfuel...such effects were observed can be seen directly from the flame lengths , Lc, summarized in Table 2, clearly, L., is consistently shorter for the unstable...al., 1990). Aside from the flame length observations discussed in connection with Table 2, the flame surfaces for stable conditions were much

Entanglement entropy in a one-dimensional disordered interacting system: the role of localization.

PubMed

Berkovits, Richard

2012-04-27

The properties of the entanglement entropy (EE) in one-dimensional disordered interacting systems are studied. Anderson localization leaves a clear signature on the average EE, as it saturates on the length scale exceeding the localization length. This is verified by numerically calculating the EE for an ensemble of disordered realizations using the density matrix renormalization group method. A heuristic expression describing the dependence of the EE on the localization length, which takes into account finite-size effects, is proposed. This is used to extract the localization length as a function of the interaction strength. The localization length dependence on the interaction fits nicely with the expectations.

Quantum discord length is enhanced while entanglement length is not by introducing disorder in a spin chain.

PubMed

Sadhukhan, Debasis; Roy, Sudipto Singha; Rakshit, Debraj; Prabhu, R; Sen De, Aditi; Sen, Ujjwal

2016-01-01

Classical correlation functions of ground states typically decay exponentially and polynomially, respectively, for gapped and gapless short-range quantum spin systems. In such systems, entanglement decays exponentially even at the quantum critical points. However, quantum discord, an information-theoretic quantum correlation measure, survives long lattice distances. We investigate the effects of quenched disorder on quantum correlation lengths of quenched averaged entanglement and quantum discord, in the anisotropic XY and XYZ spin glass and random field chains. We find that there is virtually neither reduction nor enhancement in entanglement length while quantum discord length increases significantly with the introduction of the quenched disorder.

[Construction of dengue virus-specific full-length fully human antibody libraries by mammalian display technology].

PubMed

Wen, Yangming; Lan, Kaijian; Wang, Junjie; Yu, Jingyi; Qu, Yarong; Zhao, Wei; Zhang, Fuchun; Tan, Wanlong; Cao, Hong; Zhou, Chen

2013-06-01

To construct dengue virus-specific full-length fully human antibody libraries using mammalian cell surface display technique. Total RNA was extracted from peripheral blood mononuclear cells (PBMCs) from convalescent patients with dengue fever. The reservoirs of the light chain and heavy chain variable regions (LCκ and VH) of the antibody genes were amplified by RT-PCR and inserted into the vector pDGB-HC-TM separately to construct the light chain and heavy chain libraries. The library DNAs were transfected into CHO cells and the expression of full-length fully human antibodies on the surface of CHO cells was analyzed by flow cytometry. Using 1.2 µg of the total RNA isolated from the PBMCs as the template, the LCκ and VH were amplified and the full-length fully human antibody mammalian display libraries were constructed. The kappa light chain gene library had a size of 1.45×10(4) and the heavy chain gene library had a size of 1.8×10(5). Sequence analysis showed that 8 out of the 10 light chain clones and 7 out of the 10 heavy chain clones randomly picked up from the constructed libraries contained correct open reading frames. FACS analysis demonstrated that all the 15 clones with correct open reading frames expressed full-length antibodies, which could be detected on CHO cell surfaces. After co-transfection of the heavy chain and light chain gene libraries into CHO cells, the expression of full-length antibodies on CHO cell surfaces could be detected by FACS analysis with an expressible diversity of the antibody library reaching 1.46×10(9) [(1.45×10(4)×80%)×(1.8×10(5)×70%)]. Using 1.2 µg of total RNA as template, the LCκ and VH full-length fully human antibody libraries against dengue virus have been successfully constructed with an expressible diversity of 10(9).

Soybean cell enlargement oscillates with a temperature-compensated period length of ca. 24 min

NASA Technical Reports Server (NTRS)

Morre, D. J.; Pogue, R.; Morre, D. M.

2001-01-01

Rate of enlargement of epidermal cells from soybean, when measured at intervals of 1 min using a light microscope equipped with a video measurement system, oscillated with a period length of about 24 min. This oscillation parallels the 24-min periodicity observed for the oxidation of NADH by the external plasma membrane NADH oxidase. The increase in length was not only non-linear, but intervals of rapid increase in area alternated with intervals of rapid decrease in area. The length of the period was temperature compensated, and was approximately the same when measured at 14, 24 and 34 degrees C even though the rate of cell enlargement varied over this same range of temperatures. These observations represent the first demonstration of an oscillatory growth behavior correlated with a biochemical activity where the period length of both is independent of temperature (temperature compensated) as is the hallmark of clock-related biological phenomena.

First principles prediction of amorphous phases using evolutionary algorithms

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

Nahas, Suhas, E-mail: shsnhs@iitk.ac.in; Gaur, Anshu, E-mail: agaur@iitk.ac.in; Bhowmick, Somnath, E-mail: bsomnath@iitk.ac.in

2016-07-07

We discuss the efficacy of evolutionary method for the purpose of structural analysis of amorphous solids. At present, ab initio molecular dynamics (MD) based melt-quench technique is used and this deterministic approach has proven to be successful to study amorphous materials. We show that a stochastic approach motivated by Darwinian evolution can also be used to simulate amorphous structures. Applying this method, in conjunction with density functional theory based electronic, ionic and cell relaxation, we re-investigate two well known amorphous semiconductors, namely silicon and indium gallium zinc oxide. We find that characteristic structural parameters like average bond length and bondmore » angle are within ∼2% of those reported by ab initio MD calculations and experimental studies.« less

Magnetic propulsion of robotic sperms at low-Reynolds number

NASA Astrophysics Data System (ADS)

Khalil, Islam S. M.; Fatih Tabak, Ahmet; Klingner, Anke; Sitti, Metin

2016-07-01

We investigate the microswimming behaviour of robotic sperms in viscous fluids. These robotic sperms are fabricated from polystyrene dissolved in dimethyl formamide and iron-oxide nanoparticles. This composition allows the nanoparticles to be concentrated within the bead of the robotic sperm and provide magnetic dipole, whereas the flexibility of the ultra-thin tail enables flagellated locomotion using magnetic fields in millitesla range. We show that these robotic sperms have similar morphology and swimming behaviour to those of sperm cells. Moreover, we show experimentally that our robotic sperms swim controllably at an average speed of approximately one body length per second (around 125 μm s-1), and they are relatively faster than the microswimmers that depend on planar wave propulsion in low-Reynolds number fluids.

Perspective: Theory and simulation of hybrid halide perovskites

PubMed Central

Jung, Young-Kwang

2017-01-01

Organic-inorganic halide perovskites present a number of challenges for first-principles atomistic materials modeling. Such “plastic crystals” feature dynamic processes across multiple length and time scales. These include the following: (i) transport of slow ions and fast electrons; (ii) highly anharmonic lattice dynamics with short phonon lifetimes; (iii) local symmetry breaking of the average crystallographic space group; (iv) strong relativistic (spin-orbit coupling) effects on the electronic band structure; and (v) thermodynamic metastability and rapid chemical breakdown. These issues, which affect the operation of solar cells, are outlined in this perspective. We also discuss general guidelines for performing quantitative and predictive simulations of these materials, which are relevant to metal-organic frameworks and other hybrid semiconducting, dielectric and ferroelectric compounds. PMID:29166078

Identifying Developmental Zones in Maize Lateral Root Cell Length Profiles using Multiple Change-Point Models

PubMed Central

Moreno-Ortega, Beatriz; Fort, Guillaume; Muller, Bertrand; Guédon, Yann

2017-01-01

The identification of the limits between the cell division, elongation and mature zones in the root apex is still a matter of controversy when methods based on cellular features, molecular markers or kinematics are compared while methods based on cell length profiles have been comparatively underexplored. Segmentation models were developed to identify developmental zones within a root apex on the basis of epidermal cell length profiles. Heteroscedastic piecewise linear models were estimated for maize lateral roots of various lengths of both wild type and two mutants affected in auxin signaling (rtcs and rum-1). The outputs of these individual root analyses combined with morphological features (first root hair position and root diameter) were then globally analyzed using principal component analysis. Three zones corresponding to the division zone, the elongation zone and the mature zone were identified in most lateral roots while division zone and sometimes elongation zone were missing in arrested roots. Our results are consistent with an auxin-dependent coordination between cell flux, cell elongation and cell differentiation. The proposed segmentation models could extend our knowledge of developmental regulations in longitudinally organized plant organs such as roots, monocot leaves or internodes. PMID:29123533

Telomere length analysis.

PubMed

Canela, Andrés; Klatt, Peter; Blasco, María A

2007-01-01

Most somatic cells of long-lived species undergo telomere shortening throughout life. Critically short telomeres trigger loss of cell viability in tissues, which has been related to alteration of tissue function and loss of regenerative capabilities in aging and aging-related diseases. Hence, telomere length is an important biomarker for aging and can be used in the prognosis of aging diseases. These facts highlight the importance of developing methods for telomere length determination that can be employed to evaluate telomere length during the human aging process. Telomere length quantification methods have improved greatly in accuracy and sensitivity since the development of the conventional telomeric Southern blot. Here, we describe the different methodologies recently developed for telomere length quantification, as well as their potential applications for human aging studies.

Telomere length profiles in primary human peritoneal mesothelial cells are consistent with senescence.

PubMed

Lopez-Anton, Melisa; Rudolf, András; Baird, Duncan M; Roger, Laureline; Jones, Rhiannon E; Witowski, Janusz; Fraser, Donald J; Bowen, Timothy

2017-06-01

Mesothelial cell (MC) senescence contributes to malignancy and tissue fibrosis. The role of telomere erosion in MC senescence remains controversial, with evidence for both telomere-dependent and telomere-independent mechanisms reported. Single telomere length analysis revealed considerable telomere length heterogeneity in freshly isolated human peritoneal MCs, reflecting a heterogeneous proliferative history and providing high-resolution evidence for telomere-dependent senescence. By contrast the attenuated replicative lifespan, lack of telomere erosion and induction of p16 expression in in vitro-aged cells was consistent with stress-induced senescence. Given the potential pathophysiological impact of senescence in mesothelial tissues, high-resolution MC telomere length analysis may provide clinically useful information. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Broadband Epsilon-near-Zero Reflectors Enhance the Quantum Efficiency of Thin Solar Cells at Visible and Infrared Wavelengths.

PubMed

Labelle, A J; Bonifazi, M; Tian, Y; Wong, C; Hoogland, S; Favraud, G; Walters, G; Sutherland, B; Liu, M; Li, Jun; Zhang, Xixiang; Kelley, S O; Sargent, E H; Fratalocchi, A

2017-02-15

The engineering of broadband absorbers to harvest white light in thin-film semiconductors is a major challenge in developing renewable materials for energy harvesting. Many solution-processed materials with high manufacturability and low cost, such as semiconductor quantum dots, require the use of film structures with thicknesses on the order of 1 μm to absorb incoming photons completely. The electron transport lengths in these media, however, are 1 order of magnitude smaller than this length, hampering further progress with this platform. Herein, we show that, by engineering suitably disordered nanoplasmonic structures, we have created a new class of dispersionless epsilon-near-zero composite materials that efficiently harness white light. Our nanostructures localize light in the dielectric region outside the epsilon-near-zero material with characteristic lengths of 10-100 nm, resulting in an efficient system for harvesting broadband light when a thin absorptive film is deposited on top of the structure. By using a combination of theory and experiments, we demonstrate that ultrathin layers down to 50 nm of colloidal quantum dots deposited atop the epsilon-near-zero material show an increase in broadband absorption ranging from 200% to 500% compared to a planar structure of the same colloidal quantum-dot-absorber average thickness. When the epsilon-near-zero nanostructures were used in an energy-harvesting module, we observed a spectrally averaged 170% broadband increase in the external quantum efficiency of the device, measured at wavelengths between 400 and 1200 nm. Atomic force microscopy and photoluminescence excitation measurements demonstrate that the properties of these epsilon-near-zero structures apply to general metals and could be used to enhance the near-field absorption of semiconductor structures more widely. We have developed an inexpensive electrochemical deposition process that enables scaled-up production of this nanomaterial for large-scale energy-harvesting applications.

Microtubule Dynamics Scale with Cell Size to Set Spindle Length and Assembly Timing.

PubMed

Lacroix, Benjamin; Letort, Gaëlle; Pitayu, Laras; Sallé, Jérémy; Stefanutti, Marine; Maton, Gilliane; Ladouceur, Anne-Marie; Canman, Julie C; Maddox, Paul S; Maddox, Amy S; Minc, Nicolas; Nédélec, François; Dumont, Julien

2018-05-21

Successive cell divisions during embryonic cleavage create increasingly smaller cells, so intracellular structures must adapt accordingly. Mitotic spindle size correlates with cell size, but the mechanisms for this scaling remain unclear. Using live cell imaging, we analyzed spindle scaling during embryo cleavage in the nematode Caenorhabditis elegans and sea urchin Paracentrotus lividus. We reveal a common scaling mechanism, where the growth rate of spindle microtubules scales with cell volume, which explains spindle shortening. Spindle assembly timing is, however, constant throughout successive divisions. Analyses in silico suggest that controlling the microtubule growth rate is sufficient to scale spindle length and maintain a constant assembly timing. We tested our in silico predictions to demonstrate that modulating cell volume or microtubule growth rate in vivo induces a proportional spindle size change. Our results suggest that scalability of the microtubule growth rate when cell size varies adapts spindle length to cell volume. Copyright © 2018 Elsevier Inc. All rights reserved.

International variations in primary care physician consultation time: a systematic review of 67 countries.

PubMed

Irving, Greg; Neves, Ana Luisa; Dambha-Miller, Hajira; Oishi, Ai; Tagashira, Hiroko; Verho, Anistasiya; Holden, John

2017-11-08

To describe the average primary care physician consultation length in economically developed and low-income/middle-income countries, and to examine the relationship between consultation length and organisational-level economic, and health outcomes. This is a systematic review of published and grey literature in English, Chinese, Japanese, Spanish, Portuguese and Russian languages from 1946 to 2016, for articles reporting on primary care physician consultation lengths. Data were extracted and analysed for quality, and linear regression models were constructed to examine the relationship between consultation length and health service outcomes. One hundred and seventy nine studies were identified from 111 publications covering 28 570 712 consultations in 67 countries. Average consultation length differed across the world, ranging from 48 s in Bangladesh to 22.5 min in Sweden. We found that 18 countries representing about 50% of the global population spend 5 min or less with their primary care physicians. We also found significant associations between consultation length and healthcare spending per capita, admissions to hospital with ambulatory sensitive conditions such as diabetes, primary care physician density, physician efficiency and physician satisfaction. There are international variations in consultation length, and it is concerning that a large proportion of the global population have only a few minutes with their primary care physicians. Such a short consultation length is likely to adversely affect patient healthcare and physician workload and stress. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Using Different Standardized Methods for Species Identification: A Case Study Using Beaks from Three Ommastrephid Species

NASA Astrophysics Data System (ADS)

Hu, Guanyu; Fang, Zhou; Liu, Bilin; Chen, Xinjun; Staples, Kevin; Chen, Yong

2018-04-01

The cephalopod beak is a vital hard structure with a stable configuration and has been widely used for the identification of cephalopod species. This study was conducted to determine the best standardization method for identifying different species by measuring 12 morphological variables of the beaks of Illex argentinus, Ommastrephes bartramii, and Dosidicus gigas that were collected by Chinese jigging vessels. To remove the effects of size, these morphometric variables were standardized using three methods. The average ratios of the upper beak morphological variables and upper crest length of O. bartramii and D. gigas were found to be greater than those of I. argentinus. However, for lower beaks, only the average of LRL (lower rostrum length)/ LCL (lower crest length), LRW (lower rostrum width)/ LCL, and LLWL (lower lateral wall length)/ LCL of O. bartramii and D. gigas were greater than those of I. argentinus. The ratios of beak morphological variables and crest length were found to be all significantly different among the three species ( P < 0.001). Among the three standardization methods, the correct classification rate of stepwise discriminant analysis (SDA) was the highest using the ratios of beak morphological variables and crest length. Compared with hood length, the correct classification rate was slightly higher when using beak variables standardized by crest length using an allometric model. The correct classification rate of the lower beak was also found to be greater than that of the upper beak. This study indicates that the ratios of beak morphological variables to crest length could be used for interspecies and intraspecies identification. Meanwhile, the lower beak variables were found to be more effective than upper beak variables in classifying beaks found in the stomachs of predators.

In Vivo measurement of pediatric vocal fold motion using structured light laser projection.

PubMed

Patel, Rita R; Donohue, Kevin D; Lau, Daniel; Unnikrishnan, Harikrishnan

2013-07-01

The aim of the study was to present the development of a miniature structured light laser projection endoscope and to quantify vocal fold length and vibratory features related to impact stress of the pediatric glottis using high-speed imaging. The custom-developed laser projection system consists of a green laser with a 4-mm diameter optics module at the tip of the endoscope, projecting 20 vertical laser lines on the glottis. Measurements of absolute phonatory vocal fold length, membranous vocal fold length, peak amplitude, amplitude-to-length ratio, average closing velocity, and impact velocity were obtained in five children (6-9 years), two adult male and three adult female participants without voice disorders, and one child (10 years) with bilateral vocal fold nodules during modal phonation. Independent measurements made on the glottal length of a vocal fold phantom demonstrated a 0.13mm bias error with a standard deviation of 0.23mm, indicating adequate precision and accuracy for measuring vocal fold structures and displacement. First, in vivo measurements of amplitude-to-length ratio, peak closing velocity, and impact velocity during phonation in pediatric population and a child with vocal fold nodules are reported. The proposed laser projection system can be used to obtain in vivo measurements of absolute length and vibratory features in children and adults. Children have large amplitude-to-length ratio compared with typically developing adults, whereas nodules result in larger peak amplitude, amplitude-to-length ratio, average closing velocity, and impact velocity compared with typically developing children. Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

Influence of nanotube length and density on the plasmonic terahertz response of single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Karlsen, P.; Shuba, M. V.; Beckerleg, C.; Yuko, D. I.; Kuzhir, P. P.; Maksimenko, S. A.; Ksenevich, V.; Viet, Ho; Nasibulin, A. G.; Tenne, R.; Hendry, E.

2018-01-01

We measure the conductivity spectra of thin films comprising bundled single-walled carbon nanotubes (CNTs) of different average lengths in the frequency range 0.3-1000 THz and temperature interval 10-530 K. The observed temperature-induced changes in the terahertz conductivity spectra are shown to depend strongly on the average CNT length, with a conductivity around 1 THz that increases/decreases as the temperature increases for short/long tubes. This behaviour originates from the temperature dependence of the electron scattering rate, which we obtain from Drude fits of the measured conductivity in the range 0.3-2 THz for 10 μm length CNTs. This increasing scattering rate with temperature results in a subsequent broadening of the observed THz conductivity peak at higher temperatures and a shift to lower frequencies for increasing CNT length. Finally, we show that the change in conductivity with temperature depends not only on tube length, but also varies with tube density. We record the effective conductivities of composite films comprising mixtures of WS2 nanotubes and CNTs versus CNT density for frequencies in the range 0.3-1 THz, finding that the conductivity increases/decreases for low/high density films as the temperature increases. This effect arises due to the density dependence of the effective length of conducting pathways in the composite films, which again leads to a shift and temperature dependent broadening of the THz conductivity peak.

Ureter tracking and segmentation in CT urography (CTU) using COMPASS

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

Hadjiiski, Lubomir, E-mail: lhadjisk@umich.edu; Zick, David; Chan, Heang-Ping

2014-12-15

Purpose: The authors are developing a computerized system for automated segmentation of ureters in CTU, referred to as combined model-guided path-finding analysis and segmentation system (COMPASS). Ureter segmentation is a critical component for computer-aided diagnosis of ureter cancer. Methods: COMPASS consists of three stages: (1) rule-based adaptive thresholding and region growing, (2) path-finding and propagation, and (3) edge profile extraction and feature analysis. With institutional review board approval, 79 CTU scans performed with intravenous (IV) contrast material enhancement were collected retrospectively from 79 patient files. One hundred twenty-four ureters were selected from the 79 CTU volumes. On average, the uretersmore » spanned 283 computed tomography slices (range: 116–399, median: 301). More than half of the ureters contained malignant or benign lesions and some had ureter wall thickening due to malignancy. A starting point for each of the 124 ureters was identified manually to initialize the tracking by COMPASS. In addition, the centerline of each ureter was manually marked and used as reference standard for evaluation of tracking performance. The performance of COMPASS was quantitatively assessed by estimating the percentage of the length that was successfully tracked and segmented for each ureter and by estimating the average distance and the average maximum distance between the computer and the manually tracked centerlines. Results: Of the 124 ureters, 120 (97%) were segmented completely (100%), 121 (98%) were segmented through at least 70%, and 123 (99%) were segmented through at least 50% of its length. In comparison, using our previous method, 85 (69%) ureters were segmented completely (100%), 100 (81%) were segmented through at least 70%, and 107 (86%) were segmented at least 50% of its length. With COMPASS, the average distance between the computer and the manually generated centerlines is 0.54 mm, and the average maximum distance is 2.02 mm. With our previous method, the average distance between the centerlines was 0.80 mm, and the average maximum distance was 3.38 mm. The improvements in the ureteral tracking length and both distance measures were statistically significant (p < 0.0001). Conclusions: COMPASS improved significantly the ureter tracking, including regions across ureter lesions, wall thickening, and the narrowing of the lumen.« less

The average direct current offset values for small digital audio recorders in an acoustically consistent environment.

PubMed

Koenig, Bruce E; Lacey, Douglas S

2014-07-01

In this research project, nine small digital audio recorders were tested using five sets of 30-min recordings at all available recording modes, with consistent audio material, identical source and microphone locations, and identical acoustic environments. The averaged direct current (DC) offset values and standard deviations were measured for 30-sec and 1-, 2-, 3-, 6-, 10-, 15-, and 30-min segments. The research found an inverse association between segment lengths and the standard deviation values and that lengths beyond 30 min may not meaningfully reduce the standard deviation values. This research supports previous studies indicating that measured averaged DC offsets should only be used for exclusionary purposes in authenticity analyses and exhibit consistent values when the general acoustic environment and microphone/recorder configurations were held constant. Measured average DC offset values from exemplar recorders may not be directly comparable to those of submitted digital audio recordings without exactly duplicating the acoustic environment and microphone/recorder configurations. © 2014 American Academy of Forensic Sciences.

CLINICAL CHARACTERISTICS OF IDIOPATHIC FOVEOMACULAR RETINOSCHISIS.

PubMed

Maruko, Ichiro; Morizane, Yuki; Kimura, Shuhei; Shiode, Yusuke; Hosokawa, Mio; Sekiryu, Tetsuju; Iida, Tomohiro; Shiraga, Fumio

2016-08-01

To describe the clinical features of idiopathic foveomacular retinoschisis not in association with myopia, glaucoma, optic disk pit, or juvenile retinoschisis. Retrospective observational case series. Five eyes of five patients with idiopathic foveomacular retinoschisis were included. The patients were 2 men and 3 women (average age, 75.2 years; range, 71-78 years). The average spherical equivalent was +2.40 diopters (range, +0.88 to +5.75 diopters), and the average axial length was 22.0 mm (range, 21.1-23.1 mm). All patients had retinoschisis from the macula to the optic disk in the affected eye. No patients had retinoschisis in the fellow eye. The average best-corrected visual acuity was 20/44 (68 Early Treatment Diabetic Retinopathy Study letter score). Idiopathic foveomacular retinoschisis is not inherited or associated with myopia, vitreomacular traction syndrome, optic pit, or glaucoma but is associated with older age, unilaterality, hyperopia with short axial length, complete posterior vitreous detachment, and weak leakage from the optic disk on fluorescein angiography.

Determinants of Major League Baseball Pitchers' Career Length.

PubMed

Hardy, Rich; Ajibewa, Tiwaloluwa; Bowman, Ray; Brand, Jefferson C

2017-02-01

To investigate variables (injury, position, performance, and pitching volume) that affect the career longevity of Major League Baseball pitchers. To be eligible, pitchers must have entered Major League Baseball between 1989 and 1992 without missing information for the variables on the website http://www.baseball-reference.com. The variables assessed were average innings pitched per year before and after age 25 years, earned run average, walks and hits divided by innings pitched, strikeout to walk ratio, pitching position, time on the disabled list, length of career, and starting and retirement age. We used analysis of variance to compare the differences between groups and a regression model to assess the relationship between variables before age 25 years and career length. Mean retirement age for the group was 31.74 (95% confidence interval 30.83-32.65) and mean career length was 10.97 (95% confidence interval, 10.02-11.92) years. Innings pitched after age 25 years increased slightly, but not significantly, from the number of innings pitched before age 25 years, 85.35 versus 74.25, P = .5063. Career earned run average was not significantly different after age 25 years compared with before age 25 years, 4.83 versus 5.58, respectively, P = .8834. Both strikeout to walk ratio, 1.55 to 1.77, P = .0022, and walks and hits divided by innings pitched, 1.63 to 1.50, P = .0339, improved significantly after age 25 years compared with before age 25 years. The position the player started and ended his career (starter or reliever) did not influence career length. Multiple regression analysis comparing the variables from before age 25 revealed only the number of innings pitched before age 25 were positively related to career length, R 2  = 0.1408, P < .0001. All other variables analyzed before age 25 years were not significantly related to career length. The only studied variable that had significant relationship, which was weak to low, with career length was innings pitched per year before age 25 years. All other variables analyzed before age 25 years were not significantly related to career length. Level IV, case series. Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

A numerical simulation of finite-length Taylor-Couette flow

NASA Technical Reports Server (NTRS)

Streett, C. L.; Hussaini, M. Y.

1988-01-01

Results from numerical simulations of finite-length Taylor-Couette flow are presented. Included are time-accurate and steady-state studies of the change in the nature of the symmetric two-cell/asymmetric one-cell bifurcation with varying aspect ratio and of the Reynolds number/aspect ratio locus of the two-cell/four-cell bifurcation. Preliminary results from wavy-vortex simulations at low aspect ratios are also presented.

Finite length Taylor Couette flow

NASA Technical Reports Server (NTRS)

Streett, C. L.; Hussaini, M. Y.

1987-01-01

Axisymmetric numerical solutions of the unsteady Navier-Stokes equations for flow between concentric rotating cylinders of finite length are obtained by a spectral collocation method. These representative results pertain to two-cell/one-cell exchange process, and are compared with recent experiments.

Minimum size limits for yellow perch (Perca flavescens) in western Lake Erie

USGS Publications Warehouse

Hartman, Wilbur L.; Nepszy, Stephen J.; Scholl, Russell L.

1980-01-01

During the 1960's yellow perch (Perca flavescens) of Lake Erie supported a commercial fishery that produced an average annual catch of 23 million pounds, as well as a modest sport fishery. Since 1969, the resource has seriously deteriorated. Commercial landings amounted to only 6 million pounds in 1976, and included proportionally more immature perch than in the 1960's. Moreover, no strong year classes were produced between 1965 and 1975. An interagency technical committee was appointed in 1975 by the Lake Erie Committee of the Great Lakes Fishery Commission to develop an interim management strategy that would provide for greater protection of perch in western Lake Erie, where declines have been the most severe. The committee first determined the age structure, growth and mortality rates, maturation schedule, and length-fecundity relationship for the population, and then applied Ricker-type equilibrium yield models to determine the effects of various minimum length limits on yield, production, average stock weight, potential egg deposition, and the Abrosov spawning frequency indicator (average number of spawning opportunities per female). The committee recommended increasing the minimum length limit of 5.0 inches to at least 8.5 inches. Theoretically, this change would increase the average stock weight by 36% and potential egg deposition by 44%, without significantly decreasing yield. Abrosov's spawning frequency indicator would rise from the existing 0.6 to about 1.2.

Morphology and morphometry of the reproductive system of female Saguinus midas (Linnaeus, 1758).

PubMed

Monteiro, Nathaly Cristine Da Silva; De Lima, Ana Rita; De Carvalho, Ana Flávia; De Carvalho Garcia, Rafael; Therrier, Joanne; Souza, Ana Carla Barros; Pereira, Luiza Correia; Branco, Erika

2012-06-01

In this article, the reproductive system's morphology of three young animals of the species Saguinus midas, from the bauxite mine in Paragominas, is described. The specimens were fixed and preserved in a solution of 10% aqueous formaldehyde, followed by dissection, measurement of the genital organs (uterus, vagina, ovaries, and uterine tubes), and histological processing. The vulva is delimited by the labia, with a clitoris. It is lined by keratinized stratified squamous epithelium with sebaceous glands of holocrine secretion. The vagina is an elongated tube with an average length of 26 mm and diameter of 1 mm, presenting a non-keratinized squamous epithelium, disposed between the vestibule of the vagina and cervix, the latter being relatively short. The uterus is simple, has globular shape and is located in the caudal portion of the abdominal cavity, with an average length of 14 mm and average width of 7 mm. It is formed by vascular and serous layers of muscles, and undergoes a bifurcation to form two structures on the bottom of blind sac. The uterine tubes are long and convoluted with an average length of 35 mm (right) and 36 mm (left), consisting of loose connective tissue and muscle layer lined by simple ciliated columnar epithelium. The ovaries are large and ellipsoid with smooth surface. Histologically, one animal showed ovulation fosse. Copyright © 2011 Wiley Periodicals, Inc.

Real-time determination of sarcomere length of a single cardiomyocyte during contraction

PubMed Central

Kalda, Mari; Vendelin, Marko

2013-01-01

Sarcomere length of a cardiomyocyte is an important control parameter for physiology studies on a single cell level; for instance, its accurate determination in real time is essential for performing single cardiomyocyte contraction experiments. The aim of this work is to develop an efficient and accurate method for estimating a mean sarcomere length of a contracting cardiomyocyte using microscopy images as an input. The novelty in developed method lies in 1) using unbiased measure of similarities to eliminate systematic errors from conventional autocorrelation function (ACF)-based methods when applied to region of interest of an image, 2) using a semianalytical, seminumerical approach for evaluating the similarity measure to take into account spatial dependence of neighboring image pixels, and 3) using a detrend algorithm to extract the sarcomere striation pattern content from the microscopy images. The developed sarcomere length estimation procedure has superior computational efficiency and estimation accuracy compared with the conventional ACF and spectral analysis-based methods using fast Fourier transform. As shown by analyzing synthetic images with the known periodicity, the estimates obtained by the developed method are more accurate at the subpixel level than ones obtained using ACF analysis. When applied in practice on rat cardiomyocytes, our method was found to be robust to the choice of the region of interest that may 1) include projections of carbon fibers and nucleus, 2) have uneven background, and 3) be slightly disoriented with respect to average direction of sarcomere striation pattern. The developed method is implemented in open-source software. PMID:23255581

The predictive power of local properties of financial networks

NASA Astrophysics Data System (ADS)

Caraiani, Petre

2017-01-01

The literature on analyzing the dynamics of financial networks has focused so far on the predictive power of global measures of networks like entropy or index cohesive force. In this paper, I show that the local network properties have similar predictive power. I focus on key network measures like average path length, average degree or cluster coefficient, and also consider the diameter and the s-metric. Using Granger causality tests, I show that some of these measures have statistically significant prediction power with respect to the dynamics of aggregate stock market. Average path length is most robust relative to the frequency of data used or specification (index or growth rate). Most measures are found to have predictive power only for monthly frequency. Further evidences that support this view are provided through a simple regression model.

Quantifying intermediate-frequency heterogeneities of SOFC electrodes using X-ray computed tomography

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

Epting, William K.; Mansley, Zachary; Menasche, David B.

2017-03-03

The electrodes in solid oxide fuel cells (SOFCs) consist of three phases interconnected in three dimensions. The volume needed to describe quantitatively such microstructures depends on several lengths scales, which are functions of materials properties and fabrication methods. This work focuses on quantifying the volume needed to represent “intermediate frequency” heterogeneities in electrodes of a commercial SOFC using X-ray computed tomography (CT) over two different length scales. Electrode volumes of 150 x 150 x 9 μm 3 were extracted from a synchrotron-based micro-CT data set, with 13 μm 3 voxels. 13.6 x 19.8 x 19.4 μm 3 of the cathodemore » and 26.3 x 24.8 x 15.7 μm 3 of the anode were extracted from laboratory nano-CT data sets, both with 65 3 nm 3 voxels. After comparing the variation across sub-regions for the greyscale values from the micro-CT, and for the phase fractions and triple phase boundary densities from the nano-CT, it was found that the sub-region length scales needed to yield statistically similar average values were an order of magnitude larger than those expected to capture the “high frequency” heterogeneity related to the discrete nature of the three phases in electrodes. In conclusion, the challenge of quantifying such electrodes using available experimental methods is discussed.« less

Maintenance of telomere length in AML.

PubMed

Lansdorp, Peter M

2017-11-28

The importance of telomere length to human health, aging, and cancer continues to be underappreciated. This review examines some basics of telomere biology and relates how telomere function, telomerase activity, and mutations in TERC or TERT are involved in bone marrow failure, leukemias, and other cancers. Given the challenge to obtain accurate data on telomerase activity and telomere length in specific cell types, the situation in acute myeloid leukemia (AML) remains puzzling. In most cancers, telomerase levels are increased after cells have encountered a "telomere crisis," which is typically associated with poor prognosis. Cells emerging from "telomere crisis" have defective DNA damage responses, resulting, for example, from loss of p53. Such cells often express elevated telomerase levels as a result of point mutations in the TERT promoter or amplification of the TERT gene. While telomeres in AML blasts are typically shorter than expected for normal leukocytes, most AML cells do not show evidence of having gone through a "telomere crisis." In chronic myeloid leukemia (CML), the difference between the telomere length in nonmalignant T cells and malignant blasts from the same patient was found to correlate with the remaining duration of the chronic phase. This observation supports that a mitotic clock is ticking in CML stem cells and that disease progression in CML heralds the onset of a "telomere crisis." The presence of very short telomeres in tumor cells was found to predict disease progression in chronic lymphocytic leukemia, myeloma, and various solid tumors. In view of these findings longitudinal studies of telomere length in AML appear worthwhile.

Extreme Telomere Length Dimorphism in the Tasmanian Devil and Related Marsupials Suggests Parental Control of Telomere Length

PubMed Central

Bender, Hannah S.; Murchison, Elizabeth P.; Pickett, Hilda A.; Deakin, Janine E.; Strong, Margaret A.; Conlan, Carly; McMillan, Daniel A.; Neumann, Axel A.; Greider, Carol W.; Hannon, Gregory J.; Reddel, Roger R.; Graves, Jennifer A. Marshall.

2012-01-01

Telomeres, specialised structures that protect chromosome ends, play a critical role in preserving chromosome integrity. Telomere dynamics in the Tasmanian devil (Sarcophilus harrisii) are of particular interest in light of the emergence of devil facial tumour disease (DFTD), a transmissible malignancy that causes rapid mortality and threatens the species with extinction. We used fluorescent in situ hybridisation to investigate telomere length in DFTD cells, in healthy Tasmanian devils and in four closely related marsupial species. Here we report that animals in the Order Dasyuromorphia have chromosomes characterised by striking telomere length dimorphism between homologues. Findings in sex chromosomes suggest that telomere length dimorphism may be regulated by events in the parental germlines. Long telomeres on the Y chromosome imply that telomere lengthening occurs during spermatogenesis, whereas telomere diminution occurs during oogenesis. Although found in several somatic cell tissue types, telomere length dimorphism was not found in DFTD cancer cells, which are characterised by uniformly short telomeres. This is, to our knowledge, the first report of naturally occurring telomere length dimorphism in any species and suggests a novel strategy of telomere length control. Comparative studies in five distantly related marsupials and a monotreme indicate that telomere dimorphism evolved at least 50 million years ago. PMID:23049977

Chemical Reactions in Turbulent Mixing Flows

DTIC Science & Technology

1991-09-14

explored Reynolds number effects on turbulent flame length and the influence of buoyancy on turbulent jet flames; 2. completion of a thesis entitled...the dependence of flame length on Reynolds number was begun, and the issue of buoyancy was investigated. L._Lw~ Pt-lO%Rh 2 ൡ g rn wire Flame L ZoneY...105. The flame length at a given Reynolds number was determined from the time-averaged, line- integrated temperature measurements performed by the cold

Tankyrase 2 Poly(ADP-Ribose) Polymerase Domain-Deleted Mice Exhibit Growth Defects but Have Normal Telomere Length and Capping

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

Hsiao, Susan J; Poitras, Marc; Cook, Brandoch

Regulation of telomere length maintenance and capping are a critical cell functions in both normal and tumor cells. Tankyrase 2 (Tnks2) is a poly(ADP-ribose) polymerase (PARP) that has been shown to modify itself and TRF1, a telomere-binding protein. We show here by overexpression studies that tankyrase 2, like its closely related homolog tankyrase 1, can function as a positive regulator of telomere length in human cells, dependent on its catalytic PARP activity. To study the role of Tnks2 in vivo, we generated mice with the Tnks2 PARP domain deleted. These mice are viable and fertile but display a growth retardationmore » phenotype. Telomere analysis by quantitative fluorescence in situ hybridization (FISH), flow-FISH, and restriction fragment analysis showed no change in telomere length or telomere capping in these mice. To determine the requirement foTnks2 in long-term maintenance of telomeres, we generated embryonic stem cells with the Tnks2 PARP domain deleted and observed no change, even upon prolonged growth, in telomere length or telomere capping. Together these results suggest that Tnkjs2 has a role in normal growth and development but is not essential for telomere length maintenance or telomere capping in mice.« less

Cache-enabled small cell networks: modeling and tradeoffs.

PubMed

Baştuǧ, Ejder; Bennis, Mehdi; Kountouris, Marios; Debbah, Mérouane

We consider a network model where small base stations (SBSs) have caching capabilities as a means to alleviate the backhaul load and satisfy users' demand. The SBSs are stochastically distributed over the plane according to a Poisson point process (PPP) and serve their users either (i) by bringing the content from the Internet through a finite rate backhaul or (ii) by serving them from the local caches. We derive closed-form expressions for the outage probability and the average delivery rate as a function of the signal-to-interference-plus-noise ratio (SINR), SBS density, target file bitrate, storage size, file length, and file popularity. We then analyze the impact of key operating parameters on the system performance. It is shown that a certain outage probability can be achieved either by increasing the number of base stations or the total storage size. Our results and analysis provide key insights into the deployment of cache-enabled small cell networks (SCNs), which are seen as a promising solution for future heterogeneous cellular networks.

Laparoscopic nephroureterectomy: making management of upper-tract transitional-cell carcinoma entirely minimally invasive.

PubMed

Keeley, F X; Tolley, D A

1998-04-01

Endoscopic treatment of upper-tract transitional-cell carcinoma (TCC) is well established. Nevertheless, many patients still required major ablative surgery. We have applied our experience with laparoscopic nephrectomy to the performance of laparoscopic nephroureterectomy in order to make the management of upper-tract TCC entirely minimally invasive. Since 1993, we have performed 22 laparoscopic nephroureterectomies for upper-tract TCC. Initially, we excluded patients with tumors below the pelvic brim, but we now offer a trial of laparoscopy to all patients. We describe the evolution of our technique, which involves resecting the ureteral orifice prior to laparoscopic dissection of the kidney and ureter. We have had to convert three cases to open surgery, one each for bleeding, failure to progress, and unappreciated tumor extent. Operative times averaged 156 minutes, which compares well with contemporary times for open nephroureterectomy. Complication rates, transfusion requirements, and length of stay, although higher than those of laparoscopic nephrectomy, were all reduced in comparison with open nephroureterectomy.

Explicit Analytical Solution of a Pendulum with Periodically Varying Length

ERIC Educational Resources Information Center

Yang, Tianzhi; Fang, Bo; Li, Song; Huang, Wenhu

2010-01-01

A pendulum with periodically varying length is an interesting physical system. It has been studied by some researchers using traditional perturbation methods (for example, the averaging method). But due to the limitation of the conventional perturbation methods, the solutions are not valid for long-term prediction of the pendulum. In this paper,…

Using specific length amplified fragment sequencing to construct the high-density genetic map for Vitis (Vitis vinifera L. × Vitis amurensis Rupr.).

PubMed

Guo, Yinshan; Shi, Guangli; Liu, Zhendong; Zhao, Yuhui; Yang, Xiaoxu; Zhu, Junchi; Li, Kun; Guo, Xiuwu

2015-01-01

In this study, 149 F1 plants from the interspecific cross between 'Red Globe' (Vitis vinifera L.) and 'Shuangyou' (Vitis amurensis Rupr.) and the parent were used to construct a molecular genetic linkage map by using the specific length amplified fragment sequencing technique. DNA sequencing generated 41.282 Gb data consisting of 206,411,693 paired-end reads. The average sequencing depths were 68.35 for 'Red Globe,' 63.65 for 'Shuangyou,' and 8.01 for each progeny. In all, 115,629 high-quality specific length amplified fragments were detected, of which 42,279 were polymorphic. The genetic map was constructed using 7,199 of these polymorphic markers. These polymorphic markers were assigned to 19 linkage groups; the total length of the map was 1929.13 cm, with an average distance of 0.28 cm between each maker. To our knowledge, the genetic maps constructed in this study contain the largest number of molecular markers. These high-density genetic maps might form the basis for the fine quantitative trait loci mapping and molecular-assisted breeding of grape.

First report of the presence of Acartiabispinosa Carl, 1907 (Copepoda, Calanoida) in a semi-enclosed Bay (Sharm El-Maya), northern Red Sea with some notes on its seasonal variation in abundance and body size.

PubMed

El-Sherbiny, Mohsen M; Al-Aidaroos, Ali M

2014-01-01

The calanoid copepod, Acartiabispinosa Carl, 1907, is reported for the first time in the Red Sea, where it is found to be an important copepod in the mesozooplankton community structure of the Sharm El-Maya Bay. Female and male are fully redescribed and illustrated of as the mouthparts of this species have never previously been described and figured. Acartiabispinosa was collected in the plankton samples throughout the year and showed two peaks of abundance, a pronounced one in April (4234 individuals m(-3)), and second smaller peak during November (1784 individuals m(-3)). The average total length of females varied between 1.32 and 1.53 mm at the end of June and January respectively. For males, the average total length fluctuated between 1.07 and 1.16 mm at end of June and March respectively. Temperature showed an inverse relationship with the body length (P > 0.001) and seemed to be one of the prime factors affecting the body length of both sexes.

Quantitative analysis of production traits in saltwater crocodiles (Crocodylus porosus): II. age at slaughter.

PubMed

Isberg, S R; Thomson, P C; Nicholas, F W; Barker, S G; Moran, C

2005-12-01

Crocodile morphometric (head, snout-vent and total length) measurements were recorded at three stages during the production chain: hatching, inventory [average age (+/-SE) is 265.1 +/- 0.4 days] and slaughter (average age is 1037.8 +/- 0.4 days). Crocodile skins are used for the manufacture of exclusive leather products, with the most common-sized skin sold having 35-45 cm in belly width. One of the breeding objectives for inclusion into a multitrait genetic improvement programme for saltwater crocodiles is the time taken for a juvenile to reach this size or age at slaughter. A multivariate restricted maximum likelihood analysis provided (co)variance components for estimating the first published genetic parameter estimates for these traits. Heritability (+/-SE) estimates for the traits hatchling snout-vent length, inventory head length and age at slaughter were 0.60 (0.15), 0.59 (0.12) and 0.40 (0.10) respectively. There were strong negative genetic (-0.81 +/- 0.08) and phenotypic (-0.82 +/- 0.02) correlations between age at slaughter and inventory head length.

Extending solid state laser performance

NASA Astrophysics Data System (ADS)

Miesak, Ed

2017-02-01

Coherent Diode-Pumped Solid-State Orlando (CDO), formerly known as Lee Laser, headquartered in Orlando Florida produces CW and pulsed solid state lasers. Primary wavelengths include 1064 nm, 532 nm, and 355 nm. Other wavelengths produced include 1320 nm, 15xx nm, and 16xx nm. Pulse widths are in the range of singles to hundreds of nanoseconds. Average powers are in the range of a few watts to 1000 watts. Pulse repetition rates are typically in the range of 100 Hz to 100 KHz. Laser performance parameters are often modified according to customer requests. Laser parameters that can be adjusted include average power, pulse repetition rate, pulse length, beam quality, and wavelength. Laser parameters are typically cross-coupled such that adjusting one may change some or all of the others. Customers often request one or more parameters be changed without changing any of the remaining parameters. CDO has learned how to accomplish this successfully with rapid turn-around times and minimal cost impact. The experience gained by accommodating customer requests has produced a textbook of cause and effect combinations of laser components to accomplish almost any parameter change request. Understanding the relationships between component combinations provides valuable insight into lasing effects allowing designers to extend laser performance beyond what is currently available. This has led to several break through products, i.e. >150W average power 355 nm, >60W average power 6 ps 1064 nm, pulse lengths longer than 400 ns at 532 nm with average power >100W, >400W 532 nm with pulse lengths in the 100 ns range.

Incubation rhythm in the Fulmar Fulmarus glacialis: Annual variation and sex roles

USGS Publications Warehouse

Hatch, Scott A.

1990-01-01

I monitored the incubation schedules of Fulmars Fulmarus glacialis in an Alaskan colony by observing nests where the male and female were of different colour phases. Complete shifts of up to 16 days were recorded; the average shift in mid-incubation was 4–6 days. Mean shift length was inversely correlated with hatching success in 5 years, suggesting that Fulmars adjusted their foraging patterns to annual differences in food availability. Males assumed the larger share (55%) of incubation on average, and a larger share in years with lower hatching success. Serial correlation in the length of incubation shifts had two components - the influence of prior shift lengths on time spent foraging and individual variation. Failure of the male to relieve the female soon after laying resulted in a few breeding failures and egg losses were associated with exceptionally long shifts throughout incubation.

Estimation of the vortex length scale and intensity from two-dimensional samples

NASA Technical Reports Server (NTRS)

Reuss, D. L.; Cheng, W. P.

1992-01-01

A method is proposed for estimating flow features that influence flame wrinkling in reciprocating internal combustion engines, where traditional statistical measures of turbulence are suspect. Candidate methods were tested in a computed channel flow where traditional turbulence measures are valid and performance can be rationally evaluated. Two concepts are tested. First, spatial filtering is applied to the two-dimensional velocity distribution and found to reveal structures corresponding to the vorticity field. Decreasing the spatial-frequency cutoff of the filter locally changes the character and size of the flow structures that are revealed by the filter. Second, vortex length scale and intensity is estimated by computing the ensemble-average velocity distribution conditionally sampled on the vorticity peaks. The resulting conditionally sampled 'average vortex' has a peak velocity less than half the rms velocity and a size approximately equal to the two-point-correlation integral-length scale.

Axially staged combustion system for a gas turbine engine

DOEpatents

Bland, Robert J [Oviedo, FL

2009-12-15

An axially staged combustion system is provided for a gas turbine engine comprising a main body structure having a plurality of first and second injectors. First structure provides fuel to at least one of the first injectors. The fuel provided to the one first injector is adapted to mix with air and ignite to produce a flame such that the flame associated with the one first injector defines a flame front having an average length when measured from a reference surface of the main body structure. Each of the second injectors comprising a section extending from the reference surface of the main body structure through the flame front and having a length greater than the average length of the flame front. Second structure provides fuel to at least one of the second injectors. The fuel passes through the one second injector and exits the one second injector at a location axially spaced from the flame front.

Length dependence of force generation exhibit similarities between rat cardiac myocytes and skeletal muscle fibres.

PubMed

Hanft, Laurin M; McDonald, Kerry S

2010-08-01

According to the Frank-Starling relationship, increased ventricular volume increases cardiac output, which helps match cardiac output to peripheral circulatory demand. The cellular basis for this relationship is in large part the myofilament length-tension relationship. Length-tension relationships in maximally calcium activated preparations are relatively shallow and similar between cardiac myocytes and skeletal muscle fibres. During twitch activations length-tension relationships become steeper in both cardiac and skeletal muscle; however, it remains unclear whether length dependence of tension differs between striated muscle cell types during submaximal activations. The purpose of this study was to compare sarcomere length-tension relationships and the sarcomere length dependence of force development between rat skinned left ventricular cardiac myocytes and fast-twitch and slow-twitch skeletal muscle fibres. Muscle cell preparations were calcium activated to yield 50% maximal force, after which isometric force and rate constants (k(tr)) of force development were measured over a range of sarcomere lengths. Myofilament length-tension relationships were considerably steeper in fast-twitch fibres compared to slow-twitch fibres. Interestingly, cardiac myocyte preparations exhibited two populations of length-tension relationships, one steeper than fast-twitch fibres and the other similar to slow-twitch fibres. Moreover, myocytes with shallow length-tension relationships were converted to steeper length-tension relationships by protein kinase A (PKA)-induced myofilament phosphorylation. Sarcomere length-k(tr) relationships were distinct between all three cell types and exhibited patterns markedly different from Ca(2+) activation-dependent k(tr) relationships. Overall, these findings indicate cardiac myocytes exhibit varied length-tension relationships and sarcomere length appears a dominant modulator of force development rates. Importantly, cardiac myocyte length-tension relationships appear able to switch between slow-twitch-like and fast-twitch-like by PKA-mediated myofibrillar phosphorylation, which implicates a novel means for controlling Frank-Starling relationships.

Somatic mosaicism of androgen receptor CAG repeats in colorectal carcinoma epithelial cells from men.

PubMed

Di Fabio, Francesco; Alvarado, Carlos; Gologan, Adrian; Youssef, Emad; Voda, Linda; Mitmaker, Elliot; Beitel, Lenore K; Gordon, Philip H; Trifiro, Mark

2009-06-01

The X-linked human androgen receptor gene (AR) contains an exonic polymorphic trinucleotide CAG. The length of this encoded CAG tract inversely affects AR transcriptional activity. Colorectal carcinoma is known to express the androgen receptor, but data on somatic CAG repeat lengths variations in malignant and normal epithelial cells are still sporadic. Using laser capture microdissection (LCM), epithelial cells from colorectal carcinoma and normal-appearing mucosa were collected from the fresh tissue of eight consecutive male patients undergoing surgery (mean age, 70 y; range, 54-82). DNA isolated from each LCM sample underwent subsequent PCR and DNA sequencing to precisely determine AR CAG repeat lengths and the presence of microsatellite instability (MSI). Different AR CAG repeat lengths were observed in colorectal carcinoma (ranging from 0 to 36 CAG repeats), mainly in the form of multiple shorter repeat lengths. This genetic heterogeneity (somatic mosaicism) was also found in normal-appearing colorectal mucosa. Half of the carcinoma cases examined tended to have a higher number of AR CAG repeat lengths with a wider range of repeat size variation compared to normal mucosa. MSI carcinomas tended to have longer median AR CAG repeat lengths (n = 17) compared to microsatellite stable carcinomas (n = 14), although the difference was not significant (P = 0.31, Mann-Whitney test). Multiple unique somatic mutations of the AR CAG repeats occur in colorectal mucosa and in carcinoma, predominantly resulting in shorter alleles. Colorectal epithelial cells carrying AR alleles with shorter CAG repeat lengths may be more androgen-sensitive and therefore have a growth advantage.

Cell elongation is an adaptive response for clearing long chromatid arms from the cleavage plane

PubMed Central

Kotadia, Shaila; Montembault, Emilie; Sullivan, William

2012-01-01

Chromosome segregation must be coordinated with cell cleavage to ensure correct transmission of the genome to daughter cells. Here we identify a novel mechanism by which Drosophila melanogaster neuronal stem cells coordinate sister chromatid segregation with cleavage furrow ingression. Cells adapted to a dramatic increase in chromatid arm length by transiently elongating during anaphase/telophase. The degree of cell elongation correlated with the length of the trailing chromatid arms and was concomitant with a slight increase in spindle length and an enlargement of the zone of cortical myosin distribution. Rho guanine-nucleotide exchange factor (Pebble)–depleted cells failed to elongate during segregation of long chromatids. As a result, Pebble-depleted adult flies exhibited morphological defects likely caused by cell death during development. These studies reveal a novel pathway linking trailing chromatid arms and cortical myosin that ensures the clearance of chromatids from the cleavage plane at the appropriate time during cytokinesis, thus preserving genome integrity. PMID:23185030

Diffusion lengths in irradiated N/P InP-on-Si solar cells

NASA Technical Reports Server (NTRS)

Wojtczuk, Steven; Colerico, Claudia; Summers, Geoffrey P.; Walters, Robert J.; Burke, Edward A.

1995-01-01

Indium phosphide (InP) solar cells are being made on silicon (Si) wafers (InP/Si) to take advantage of both the radiation-hardness properties of the InP solar cell and the light weight and low cost of Si wafers compared to InP or germanium (Ge) wafers. The InP/Si cell application is for long duration and/or high radiation orbit space missions. InP/Si cells have higher absolute efficiency after a high radiation dose than gallium arsenide (GaAs) or silicon (Si) solar cells. In this work, base electron diffusion lengths in the N/P cell are extracted from measured AM0 short-circuit photocurrent at various irradiation levels out to an equivalent 1 MeV fluence of 1017 1 MeV electrons/sq cm for a 1 sq cm 12% BOL InP/Si cell. These values are then checked for consistency by comparing measured Voc data with a theoretical Voc model that includes a dark current term that depends on the extracted diffusion lengths.

Effects of Circular DNA Length on Transfection Efficiency by Electroporation into HeLa Cells.

PubMed

Hornstein, Benjamin D; Roman, Dany; Arévalo-Soliz, Lirio M; Engevik, Melinda A; Zechiedrich, Lynn

2016-01-01

The ability to produce extremely small and circular supercoiled vectors has opened new territory for improving non-viral gene therapy vectors. In this work, we compared transfection of supercoiled DNA vectors ranging from 383 to 4,548 bp, each encoding shRNA against GFP under control of the H1 promoter. We assessed knockdown of GFP by electroporation into HeLa cells. All of our vectors entered cells in comparable numbers when electroporated with equal moles of DNA. Despite similar cell entry, we found length-dependent differences in how efficiently the vectors knocked down GFP. As vector length increased up to 1,869 bp, GFP knockdown efficiency per mole of transfected DNA increased. From 1,869 to 4,257 bp, GFP knockdown efficiency per mole was steady, then decreased with increasing vector length. In comparing GFP knockdown with equal masses of vectors, we found that the shorter vectors transfect more efficiently per nanogram of DNA transfected. Our results rule out cell entry and DNA mass as determining factors for gene knockdown efficiency via electroporation. The length-dependent effects we have uncovered are likely explained by differences in nuclear translocation or transcription. These data add an important step towards clinical applications of non-viral vector delivery.

Effects of Circular DNA Length on Transfection Efficiency by Electroporation into HeLa Cells

PubMed Central

Hornstein, Benjamin D.; Roman, Dany; Arévalo-Soliz, Lirio M.; Engevik, Melinda A.

2016-01-01

The ability to produce extremely small and circular supercoiled vectors has opened new territory for improving non-viral gene therapy vectors. In this work, we compared transfection of supercoiled DNA vectors ranging from 383 to 4,548 bp, each encoding shRNA against GFP under control of the H1 promoter. We assessed knockdown of GFP by electroporation into HeLa cells. All of our vectors entered cells in comparable numbers when electroporated with equal moles of DNA. Despite similar cell entry, we found length-dependent differences in how efficiently the vectors knocked down GFP. As vector length increased up to 1,869 bp, GFP knockdown efficiency per mole of transfected DNA increased. From 1,869 to 4,257 bp, GFP knockdown efficiency per mole was steady, then decreased with increasing vector length. In comparing GFP knockdown with equal masses of vectors, we found that the shorter vectors transfect more efficiently per nanogram of DNA transfected. Our results rule out cell entry and DNA mass as determining factors for gene knockdown efficiency via electroporation. The length-dependent effects we have uncovered are likely explained by differences in nuclear translocation or transcription. These data add an important step towards clinical applications of non-viral vector delivery. PMID:27918590

Quantitative quasiperiodicity

NASA Astrophysics Data System (ADS)

Das, Suddhasattwa; Saiki, Yoshitaka; Sander, Evelyn; Yorke, James A.

2017-11-01

The Birkhoff ergodic theorem concludes that time averages, i.e. Birkhoff averages, B_N( f):=Σn=0N-1 f(x_n)/N of a function f along a length N ergodic trajectory (x_n) of a function T converge to the space average \\int f dμ , where μ is the unique invariant probability measure. Convergence of the time average to the space average is slow. We use a modified average of f(x_n) by giving very small weights to the ‘end’ terms when n is near 0 or N-1 . When (x_n) is a trajectory on a quasiperiodic torus and f and T are C^∞ , our weighted Birkhoff average (denoted \

Water lavage as an adjunct to cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC).

PubMed

Gabriel, Emmanuel; Singla, Smit; Kim, Minhyung; Fisher, Daniel; Powers, Colin; Visioni, Anthony; Attwood, Kristopher; Skitzki, Joseph

2017-09-01

Water lavage (WL) during gastrointestinal cancer surgery has osmotically mediated lytic effects on tumor cells. We investigated the safety and efficacy of WL with CRS-HIPEC. This is a retrospective review, 1/2003-7/2014, of a single institution experience with CRS-HIPEC comparing patients who had WL (WL+) to those who did not (WL-). Of 157 CRS-HIPECs, 16 (10.2%) were WL+. WL+ had more PCI scores >20 compared to WL- (56.3% vs 19.4%, respectively, p = 0.003); however, the completeness of cytoreduction (CC) was similar. There were no differences in hospital length of stay or post-operative complications. The average POD 1 sodium (Na) level was statistically lower in the WL+ group (133.6 ± 2.5 vs 135.5 ± 3.2 mEq/L, p = 0.023); however, the average Na at discharge for each group was 140 mEq/L. There were no differences in 3-year OS (3WL+:0.63 vs WL-:0.68, p = 0.97) or RFS (WL+:0.32 vs WL-:0.39, p = 0.47). A subset analysis for patients with PCI >20 showed no difference between groups. WL offers a low cost, safe and theoretically efficacious method of tumor cell lysis for peritoneal malignancy. Copyright © 2017 Elsevier Inc. All rights reserved.

Method for assaying clustered DNA damages

DOEpatents

Sutherland, Betsy M.

2004-09-07

Disclosed is a method for detecting and quantifying clustered damages in DNA. In this method, a first aliquot of the DNA to be tested for clustered damages with one or more lesion-specific cleaving reagents under conditions appropriate for cleavage of the DNA to produce single-strand nicks in the DNA at sites of damage lesions. The number average molecular length (Ln) of double stranded DNA is then quantitatively determined for the treated DNA. The number average molecular length (Ln) of double stranded DNA is also quantitatively determined for a second, untreated aliquot of the DNA. The frequency of clustered damages (.PHI..sub.c) in the DNA is then calculated.

Gray whale and walrus feeding excavation on the Bering Shelf, Alaska.

USGS Publications Warehouse

Nelson, C.H.; Johnson, K.R.; Barber, J.H.

1987-01-01

The gray whales (average mouth length, 2.0 m), when suction feeding on infaunal amphipods, create shallow pits in the sea floor, typically 2.5m x 1.5m x 10cm deep, which are distinct and mappable on sidescan sonographs. Similarly, walrus, when foraging for shallow clams, create long, linear feeding furrows that average 47 x 0.4 x 0.1m (length-width-depth). The whale feeding pits are commonly enlarged and oriented by seasonal storm-related scour. Walrus-feeding features are smaller, formed in higher-energy environments, and modified more rapidly than whale-feeding pits. -from Authors

Recirculation cells for granular flow in cylindrical rotating tumblers

NASA Astrophysics Data System (ADS)

D'Ortona, Umberto; Thomas, Nathalie; Lueptow, Richard M.

2018-05-01

To better understand the velocity field and flowing layer structure, we have performed a detailed discrete element method study of the flow of monodisperse particles in a partially filled three-dimensional cylindrical rotating tumblers. Similar to what occurs near the poles in spherical and conical tumblers, recirculation cells (secondary flows) develop near the flat endwalls of a cylindrical tumbler in which particles near the surface drift axially toward the endwall, while particles deeper in the flowing layer drift axially toward the midlength of the tumbler. Another recirculation cell with the opposite sense develops next to each endwall recirculation cell, extending to the midlength of the tumbler. For a long enough tumbler, each endwall cell is about one quarter of the tumbler diameter in length. Endwall cells are insensitive to tumbler length and relatively insensitive to rotation speed (so long as the flowing layer remains flat and continuously flowing) or fill level (from 25% to 50% full). However, for shorter tumblers (0.5 to 1.0 length/diameter aspect ratio) the endwall cell size does not change much, while center cells reduce their size and eventually disappear for the shortest tumblers. For longer tumblers (length/diameter aspect ratio larger than 2), a stagnation zone appears in between the central cells. These results provide insight into the mixing of monodisperse particles in rotating cylindrical tumblers as well as the frictional effects of the tumbler endwalls.

Transcriptome of the Caribbean stony coral Porites astreoides from three developmental stages.

PubMed

Mansour, Tamer A; Rosenthal, Joshua J C; Brown, C Titus; Roberson, Loretta M

2016-08-02

Porites astreoides is a ubiquitous species of coral on modern Caribbean reefs that is resistant to increasing temperatures, overfishing, and other anthropogenic impacts that have threatened most other coral species. We assembled and annotated a transcriptome from this coral using Illumina sequences from three different developmental stages collected over several years: free-swimming larvae, newly settled larvae, and adults (>10 cm in diameter). This resource will aid understanding of coral calcification, larval settlement, and host-symbiont interactions. A de novo transcriptome for the P. astreoides holobiont (coral plus algal symbiont) was assembled using 594 Mbp of raw Illumina sequencing data generated from five age-specific cDNA libraries. The new transcriptome consists of 867 255 transcript elements with an average length of 685 bases. The isolated P. astreoides assembly consists of 129 718 transcript elements with an average length of 811 bases, and the isolated Symbiodinium sp. assembly had 186 177 transcript elements with an average length of 1105 bases. This contribution to coral transcriptome data provides a valuable resource for researchers studying the ontogeny of gene expression patterns within both the coral and its dinoflagellate symbiont.

Comparison of parameters characterizing lumbar lordosis in radiograph and photogrammetric examination of adults.

PubMed

Drzał-Grabiec, Justyna; Truszczyńska, Aleksandra; Tarnowski, Adam; Płaszewski, Maciej

2015-01-01

The purpose of this study was to test validity of photogrammetry compared with radiography as a method of measuring the Cobb angle and the size of anterior-posterior spine curvatures in adults. The study included 50 volunteers, 23 men and 27 women whose mean age was 52.6 years. The average weight of the subjects was 81.3 kg, average body height was 172.0 cm, and the average body mass index was 27.4. Based on radiologic examination, the length and depth of lumbar lordosis were determined and the size of the Cobb angle of lumbar scoliosis. After the radiologic examination, a photogrammetric test was performed for each subject with the projection moire phenomenon. The Pearson correlation found statistically significant associations concerning the length of lordosis (P < .001) and the Cobb angle (P < .001). Correlation of the depth of lordosis indicated a strong trend (P = .063). This study found that the moire method of photogrammetric measurement produced similar findings to radiographic measurements in determining size of the Cobb angle and the length of lumbar lordosis. Copyright © 2015 National University of Health Sciences. Published by Elsevier Inc. All rights reserved.

On the Importance of Cycle Minimum in Sunspot Cycle Prediction

NASA Technical Reports Server (NTRS)

Wilson, Robert M.; Hathaway, David H.; Reichmann, Edwin J.

1996-01-01

The characteristics of the minima between sunspot cycles are found to provide important information for predicting the amplitude and timing of the following cycle. For example, the time of the occurrence of sunspot minimum sets the length of the previous cycle, which is correlated by the amplitude-period effect to the amplitude of the next cycle, with cycles of shorter (longer) than average length usually being followed by cycles of larger (smaller) than average size (true for 16 of 21 sunspot cycles). Likewise, the size of the minimum at cycle onset is correlated with the size of the cycle's maximum amplitude, with cycles of larger (smaller) than average size minima usually being associated with larger (smaller) than average size maxima (true for 16 of 22 sunspot cycles). Also, it was found that the size of the previous cycle's minimum and maximum relates to the size of the following cycle's minimum and maximum with an even-odd cycle number dependency. The latter effect suggests that cycle 23 will have a minimum and maximum amplitude probably larger than average in size (in particular, minimum smoothed sunspot number Rm = 12.3 +/- 7.5 and maximum smoothed sunspot number RM = 198.8 +/- 36.5, at the 95-percent level of confidence), further suggesting (by the Waldmeier effect) that it will have a faster than average rise to maximum (fast-rising cycles have ascent durations of about 41 +/- 7 months). Thus, if, as expected, onset for cycle 23 will be December 1996 +/- 3 months, based on smoothed sunspot number, then the length of cycle 22 will be about 123 +/- 3 months, inferring that it is a short-period cycle and that cycle 23 maximum amplitude probably will be larger than average in size (from the amplitude-period effect), having an RM of about 133 +/- 39 (based on the usual +/- 30 percent spread that has been seen between observed and predicted values), with maximum amplitude occurrence likely sometime between July 1999 and October 2000.

Vascular endothelial cells minimize the total force on their nuclei.

PubMed Central

Hazel, A L; Pedley, T J

2000-01-01

The vascular endothelium is a cellular monolayer that lines the arterial walls. It plays a vital role in the initiation and development of atherosclerosis, an occlusive arterial disease responsible for 50% of deaths in the Western world. The focal nature of the disease suggests that hemodynamic forces are an important factor in its pathogenesis. This has led to the investigation of the effects of mechanical forces on the endothelial cells themselves. It has been found that endothelial cells do respond to stresses induced by the flowing blood; in particular, they elongate and align with an imposed flow direction. In this paper, we calculate the distribution of force exerted on a three-dimensional hump, representing the raised cell nucleus, by a uniform shear flow. It is found that, for a nonaxisymmetric ellipsoidal hump, the least total force is experienced when the hump is aligned with the flow. Furthermore, for a hump of fixed volume, there is a specific aspect ratio combination that results in the least total force upon the hump, (0.38:2.2:1.0; height:length:width). This is approximately the same as the average aspect ratio taken up by the cell nuclei in vivo (0.27:2.23:1.0). It is possible, therefore, that the cells respond to the flow in such a way as to minimize the total force on their nuclei. PMID:10620272

Spinal instrumentation for Duchenne's muscular dystrophy: experience of hypotensive anaesthesia to minimise blood loss.

PubMed

Fox, H J; Thomas, C H; Thompson, A G

1997-01-01

Nineteen patients with Duchenne's muscular dystrophy underwent segmental spinal instrumentation and posterior fusion between 1989 and 1994. The indication for surgery was loss of the ability to walk and development of scoliosis with sitting discomfort. Preoperative assessment included evaluation of pulmonary function. Average age at operation was 12.5 years. Instrumentation and fusion extended from upper thoracic levels to L-5 or the sacrum. A Hartshill rectangle was used in all cases, with banked allograft bone. Severe intraoperative blood loss was avoided by use of hypotensive anaesthesia. Peroperatively, systolic blood pressure was maintained between 75 and 85 mm Hg. Average blood loss was 1,246 ml (range, 400-3,100) or 30% of estimated total blood volume. Average transfusion requirements were 3 units of packed cells. Postoperative analgesia was provided by infusion via an epidural catheter. There were no postoperative wound or chest infections. Three patients required catheterisation for urinary retention. Postoperatively patients were fitted with a Neofract jacket to allow early mobilisation and discharge. Mean postoperative length of stay was 16 days. Posterior spinal fusion by using the Hartshill rectangle provided good correction and fixation. Hypotensive anaesthesia permitted surgery to be performed rapidly in a relatively dry field and avoided the complications of severe intraoperative blood loss and massive transfusion.

Structure and function of bordered pits: new discoveries and impacts on whole-plant hydraulic function.

PubMed

Choat, Brendan; Cobb, Alexander R; Jansen, Steven

2008-01-01

Bordered pits are cavities in the lignified cell walls of xylem conduits (vessels and tracheids) that are essential components in the water-transport system of higher plants. The pit membrane, which lies in the center of each pit, allows water to pass between xylem conduits but limits the spread of embolism and vascular pathogens in the xylem. Averaged across a wide range of species, pits account for > 50% of total xylem hydraulic resistance, indicating that they are an important factor in the overall hydraulic efficiency of plants. The structure of pits varies dramatically across species, with large differences evident in the porosity and thickness of pit membranes. Because greater porosity reduces hydraulic resistance but increases vulnerability to embolism, differences in pit structure are expected to correlate with trade-offs between efficiency and safety of water transport. However, trade-offs in hydraulic function are influenced both by pit-level differences in structure (e.g. average porosity of pit membranes) and by tissue-level changes in conduit allometry (average length, diameter) and the total surface area of pit membranes that connects vessels. In this review we address the impact of variation in pit structure on water transport in plants from the level of individual pits to the whole plant.

Reliability of length measurements collected by community nurses and health volunteers in rural growth monitoring and promotion services.

PubMed

Laar, Matilda E; Marquis, Grace S; Lartey, Anna; Gray-Donald, Katherine

2018-02-17

Length measurements are important in growth, monitoring and promotion (GMP) for the surveillance of a child's weight-for-length and length-for-age. These two indices provide an indication of a child's risk of becoming wasted or stunted, and are more informative about a child's growth than the widely used weight-for-age index (underweight). Although the introduction of length measurements in GMP is recommended by the World Health Organization, concerns about the reliability of length measurements collected in rural outreach settings have been expressed by stakeholders. Our aim was to describe the reliability and challenges associated with community health personnel measuring length for rural outreach GMP activities. Two reliability studies (A and B), using 10 children less than 24 months each, were conducted in the GMP services of a rural district in Ghana. Fifteen nurses and 15 health volunteers (HV) with no prior experience in length measurements were trained. Intra- and inter-observer technical error of measurement (TEM), average bias from expert anthropometrist, and coefficient of reliability (R) of length measurements were assessed and compared across sessions. Observations and interviews were used to understand the ability and experiences of health personnel with measuring length at outreach GMP. Inter-observer TEM was larger than intra-observer TEM for both nurses and HV at both sessions and was unacceptably (compared to error standards) high in both groups at both time points. Average biases from expert's measurements were within acceptable limits, however, both groups tended to underestimate length measurements. The R for lengths collected by nurses (92.3%) was higher at session B compared to that of HV (87.5%). Length measurements taken by nurses and HV, and those taken by an experienced anthropometrist at GMP sessions were of moderate agreement (kappa = 0.53, p < 0.0001). The reliability of length measurements improved after two refresher trainings for nurses but not for HV. In addition, length measurements taken during GMP sessions may be susceptible to errors due to overburdened health personnel and crowded GMP clinics. There is need for both pre- and in-service training of nurses and HV on length measurements and procedures to improve reliability of length measurements.

Age, growth, and maturity of round whitefish of the Apostle Islands and Isle Royale Regions, Lake Superior

USGS Publications Warehouse

Bailey, Merryll M.

1963-01-01

The round whitefish has been of some commercial importance in the upper Great Lakes but production in Lake Superior has generally been small; the United States average was 26,600 pounds for 1929-59. This study is based on 1,173 fish collected in the Apostle Islands in 1958-60 and 103 collected at Isle Royale in 1958 and 1960. The average age of 6.0 years at Isle Royale was concluded to be significantly higher than the mean of 4.2 years in the Apostle Islands. The body-scale relation is a straight line with an intercept of 1.1 inches on the length axis. Weight of Apostle Islands round whitefish captured in several months increased as the 3.22 power of the length. Growth in length was relatively slow; nearly or fully 7 years were required to reach an acceptable commercial length of 14 inches in both the Apostle Islands and at Isle Royale. The calculated weights at the end of the seventh year were 12.6 ounces in the Apostle Islands and 13.8 ounces at Isle Royale. Minimum length at maturity of male round whitefish (7.0-7.4 inches) was less than that of females (8.5-8.9 inches). At age-group II, 11.1 percent of male round whitefish, but only 1.5 percent of the females were mature. All males were mature as age-group V and all females as age-group VI. Males dominated the younger age groups but females were more numerous in the older ones. Estimates of the number of eggs in 37 round whitefish ovaries yielded an average of 5,330 eggs for fish 10.5-17.4 inches long.

Genome Survey Sequencing for the Characterization of the Genetic Background of Rosa roxburghii Tratt and Leaf Ascorbate Metabolism Genes.

PubMed

Lu, Min; An, Huaming; Li, Liangliang

2016-01-01

Rosa roxburghii Tratt is an important commercial horticultural crop in China that is recognized for its nutritional and medicinal values. In spite of the economic significance, genomic information on this rose species is currently unavailable. In the present research, a genome survey of R. roxburghii was carried out using next-generation sequencing (NGS) technologies. Total 30.29 Gb sequence data was obtained by HiSeq 2500 sequencing and an estimated genome size of R. roxburghii was 480.97 Mb, in which the guanine plus cytosine (GC) content was calculated to be 38.63%. All of these reads were technically assembled and a total of 627,554 contigs with a N50 length of 1.484 kb and furthermore 335,902 scaffolds with a total length of 409.36 Mb were obtained. Transposable elements (TE) sequence of 90.84 Mb which comprised 29.20% of the genome, and 167,859 simple sequence repeats (SSRs) were identified from the scaffolds. Among these, the mono-(66.30%), di-(25.67%), and tri-(6.64%) nucleotide repeats contributed to nearly 99% of the SSRs, and sequence motifs AG/CT (28.81%) and GAA/TTC (14.76%) were the most abundant among the dinucleotide and trinucleotide repeat motifs, respectively. Genome analysis predicted a total of 22,721 genes which have an average length of 2311.52 bp, an average exon length of 228.15 bp, and average intron length of 401.18 bp. Eleven genes putatively involved in ascorbate metabolism were identified and its expression in R. roxburghii leaves was validated by quantitative real-time PCR (qRT-PCR). This is the first report of genome-wide characterization of this rose species.

The change is length and width of the Sertoli cell nuclei in cytologic smears of testes with depopulation of the seminiferous epithelium.

PubMed

Banek, L; Posinovec, J

1980-09-15

The appearance of the Sertoli cells in cytological smears of tests with depopulation of the seminiferous epithelium is described. The mean values of the lengths and widths of the Sertoli cell nuclei in smears differed significantly between the depopulation and the control group (p < 0.01).

Telomere dynamics, end-to-end fusions and telomerase activation during the human fibroblast immortalization process.

PubMed

Ducray, C; Pommier, J P; Martins, L; Boussin, F D; Sabatier, L

1999-07-22

Loss of telomeric repeats during cell proliferation could play a role in senescence. It has been generally assumed that activation of telomerase prevents further telomere shortening and is essential for cell immortalization. In this study, we performed a detailed cytogenetic and molecular characterization of four SV40 transformed human fibroblastic cell lines by regularly monitoring the size distribution of terminal restriction fragments, telomerase activity and the associated chromosomal instability throughout immortalization. The mean TRF lengths progressively decreased in pre-crisis cells during the lifespan of the cultures. At crisis, telomeres reached a critical size, different among the cell lines, contributing to the peak of dicentric chromosomes, which resulted mostly from telomeric associations. We observed a direct correlation between short telomere length at crisis and chromosomal instability. In two immortal cell lines, although telomerase was detected, mean telomere length still continued to decrease whereas the number of dicentric chromosomes associated was stabilized. Thus telomerase could protect specifically telomeres which have reached a critical size against end-to-end dicentrics, while long telomeres continue to decrease, although at a slower rate as before crisis. This suggests a balance between elongation by telomerase and telomere shortening, towards a stabilized 'optimal' length.

[Effect of partial ganglionectomy and acupuncture on culturing spared DRG in vitro].

PubMed

Wang, Te-Wei; Wang, Ting-Hua; Zhou, Xue; Zhang, Lian-Shuang; Xu, Xin-Yun

2005-09-01

To explore the effect of partial dorsal root rhizotomy and Acup on culturing dorsal root ganglion(DRG) in vitro. Ten adult cats were divided into 2 groups: normal control group; Acup spared DRG 7 d group, in which bilateral L1-L5, L7-S2 DRG were removed; and L6DRG were spared; then unilaterally two sets of acupoints [Zusanlily (St. 36) and Xuanzhong (G. B. 39): Futu (St. 32) and Sanyinjiao (Sp. 6) located in the distribution area of spinal nerve L6] were electro-stimulated alternatively 30 min everyday by electro-needling. Five cats were used in every group. Bilateral L6 DRGs of every group were taken out on the condition of asepsis and were cultured respectively in vitro. Cultures were terminated after day 7. Then the cultured cells were stained under the same condition using specific NSE (1 : 200) antibody, a neuron-specific marker, by the immunohistochemistry ABC method. The neurite length was measured by micro-measured ruler in upside-down light microscope on the 1st, 3rd, 5th, 7th day. Immunocytochemical staining revealed that over 95% cells were NSE positive cells which were the typical neuron of DRG in vitro; on the 1st, 3rd, 5th, 7th day, the average neurite length of the normal group was shorter than that of the spared DRG group(P < 0. 05), and the spared DRG group's was shorter than the Acup group's at each time stage (P < 0.05). These results indicated that DRG had plasticity and acupuncture probably promoted the plasticity, which were probably in close relation with the spinal plasticity.

Current Perspectives of Telomerase Structure and Function in Eukaryotes with Emerging Views on Telomerase in Human Parasites.

PubMed

Dey, Abhishek; Chakrabarti, Kausik

2018-01-24

Replicative capacity of a cell is strongly correlated with telomere length regulation. Aberrant lengthening or reduction in the length of telomeres can lead to health anomalies, such as cancer or premature aging. Telomerase is a master regulator for maintaining replicative potential in most eukaryotic cells. It does so by controlling telomere length at chromosome ends. Akin to cancer cells, most single-cell eukaryotic pathogens are highly proliferative and require persistent telomerase activity to maintain constant length of telomere and propagation within their host. Although telomerase is key to unlimited cellular proliferation in both cases, not much was known about the role of telomerase in human parasites (malaria, Trypanosoma , etc.) until recently. Since telomerase regulation is mediated via its own structural components, interactions with catalytic reverse transcriptase and several factors that can recruit and assemble telomerase to telomeres in a cell cycle-dependent manner, we compare and discuss here recent findings in telomerase biology in cancer, aging and parasitic diseases to give a broader perspective of telomerase function in human diseases.

Effectiveness of different rescanning techniques for scanned proton radiotherapy in lung cancer patients

NASA Astrophysics Data System (ADS)

Engwall, E.; Glimelius, L.; Hynning, E.

2018-05-01

Non-small cell lung cancer (NSCLC) is a tumour type thought to be well-suited for proton radiotherapy. However, the lung region poses many problems related to organ motion and can for actively scanned beams induce severe interplay effects. In this study we investigate four mitigating rescanning techniques: (1) volumetric rescanning, (2) layered rescanning, (3) breath-sampled (BS) layered rescanning, and (4) continuous breath-sampled (CBS) layered rescanning. The breath-sampled methods will spread the layer rescans over a full breathing cycle, resulting in an improved averaging effect at the expense of longer treatment times. In CBS, we aim at further improving the averaging by delivering as many rescans as possible within one breathing cycle. The interplay effect was evaluated for 4D robustly optimized treatment plans (with and without rescanning) for seven NSCLC patients in the treatment planning system RayStation. The optimization and final dose calculation used a Monte Carlo dose engine to account for the density heterogeneities in the lung region. A realistic treatment delivery time structure given from the IBA ScanAlgo simulation tool served as basis for the interplay evaluation. Both slow (2.0 s) and fast (0.1 s) energy switching times were simulated. For all seven studied patients, rescanning improves the dose conformity to the target. The general trend is that the breath-sampled techniques are superior to layered and volumetric rescanning with respect to both target coverage and variability in dose to OARs. The spacing between rescans in our breath-sampled techniques is set at planning, based on the average breathing cycle length obtained in conjunction with CT acquisition. For moderately varied breathing cycle lengths between planning and delivery (up to 15%), the breath-sampled techniques still mitigate the interplay effect well. This shows the potential for smooth implementation at the clinic without additional motion monitoring equipment.

Quality of Pinzgau bull spermatozoa following different periods of cryostorage.

PubMed

Chrenek, P; Spaleková, E; Olexikova, L; Makarevich, A; Kubovicova, E

2017-04-01

The aim of this work was to examine the influence of cryostorage duration of Pinzgau bull's insemination doses (IDs) on some sperm traits. The IDs were frozen by a slow freezing method and stored in liquid nitrogen for different periods: less than 8 years (group 1), 8-13 years (group 2) and 14-18 years (group 3). Motility (CASA), pathological sperm rate (Giemsa staining), apoptotic (Yo-Pro-1-positive) and necrotic (propidium iodide-positive) cell occurrence and fertilizing ability (penetration/fertilization test) of spermatozoa were evaluated post-thaw. The average post-thaw sperm motility in all examined groups was over 40%. No significant influence of storage length either on the sperm total motility or progressive movement was revealed. In each tested group the average rate of malformed spermatozoa did not exceed 20%. No effect of cryostorage length on the occurrence of apoptotic or necrotic sperm was noted. Similarly, penetrating/fertilizing ability of sperm did not differ among the groups, excepting differences in the rate of pronuclei (PN) formation. In group 1, 72.9% of eggs showed two visible PN following 20 h incubation with sperm, whilst in groups 2 and 3 only 67 and 54.5% of zygotes, respectively, had both PN at this time. These results revealed no influence of storage time on the bull spermatozoa in all parameters excepting the rate of PN formation. As high inter-male variability was observed in the susceptibility of bull sperm to cryostorage, individual differences should be taken into account when semen from individual bulls is to be stored for a long time.