1,580 research outputs found
Extreme bendability of DNA double helix due to bending asymmetry
Experimental data of the DNA cyclization (J-factor) at short length scales,
as a way to study the elastic behavior of tightly bent DNA, exceed the
theoretical expectation based on the wormlike chain (WLC) model by several
orders of magnitude. Here, we propose that asymmetric bending rigidity of the
double helix in the groove direction can be responsible for extreme bendability
of DNA at short length scales and it also facilitates DNA loop formation at
these lengths. To account for the bending asymmetry, we consider the asymmetric
elastic rod (AER) model which has been introduced and parametrized in an
earlier study (B. Eslami-Mossallam and M. Ejtehadi, Phys. Rev. E 80, 011919
(2009)). Exploiting a coarse grained representation of DNA molecule at base
pair (bp) level, and using the Monte Carlo simulation method in combination
with the umbrella sampling technique, we calculate the loop formation
probability of DNA in the AER model. We show that, for DNA molecule has a
larger J-factor compared to the WLC model which is in excellent agreement with
recent experimental data.Comment: 8 pages, 9 figure
Influence of gravitational field on quantum-nondemolition measurement of atomic momentum in the dispersive Jaynes-Cummings model
We present a theoretical scheme based on su(2) algebra to investigate the
influence of homogeneous gravitational field on the quantum nondemolition
measurement of atomic momentum in dispersive Jaynes-Cummings model. In the
dispersive Jaynes-Cummings model, when detuning is large and the atomic motion
is in a propagating light wave, we consider a two-level atom with quantized
cavity-field in the presence of a homogeneous gravitational field. We derive an
effective Hamiltonian describing the dispersive atom-field interaction in the
presence of gravitational field. We can see gravitational influence both on the
momentum filter and momentum distribution. Moreover, gravitational field
decreases both tooth spacing of momentum and the width of teeth of momentum.Comment: 21 pages, 8 figure
A Comparison between Recombinant Activated Factor VII (Aryoseven) and Novoseven in Patients with Congenital Factor VII Deficiency
In order to establish the efficacy and biosimilar nature of AryoSeven to NovoSeven in the treatment of congenital factor VII (FVII) deficiency, patients received either agent at 30 1/4g/kg, intravenously per week for 4 weeks, in a randomized fashion. The primary aim was to compare FVII:coagulation activity (FVII:C), 20 minutes after recombinant activated FVII (rFVIIa) injection, in the 2 groups. A secondary measure was self-reported bleeding. The median interquartile baseline range of the plasma level of activated FVII (FVIIa) activity in the 2 groups was 1.6 (1.1-14.0) IU/dL and 5.0 (1.1-25.5) IU/dL. All patients achieved levels of FVIIa (FVII:C) >30 IU/dL, 20 minutes after the injection of rFVIIa. Bleeding was similar between the 2 groups, with a comparable decrease in severity and frequency compared to the last month prior to treatment. AryoSeven is similar to NovoSeven in increasing postinjection FVIIa activity as well as in clinical safety and efficacy. © The Author(s) 2014
Copper-containing mesoporous bioactive glass promotes angiogenesis in an in vivo zebrafish model
The osteogenic and angiogenic responses of organisms to the ionic products of degradation of bioactive glasses (BGs) are being intensively investigated. The promotion of angiogenesis by copper (Cu) has been known for more than three decades. This element can be incorporated to delivery carriers, such as BGs, and the materials used in biological assays. In this work, Cu-containing mesoporous bioactive glass (MBG) in the SiO2-CaO-P2O5 compositional system was prepared incorporating 5% mol Cu (MBG-5Cu) by replacement of the corresponding amount of Ca. The biological effects of the ionic products of MBG
biodegradation were evaluated on a well-known endothelial cell line, the bovine aorta endothelial cells (BAEC), as well as in an in vivo zebrafish (Danio rerio) embryo assay. The results suggest that ionic products of both MBG (Cu free) and MBG-5Cu materials promote angiogenesis. In vitro cell cultures show that the ionic dissolution products of these materials are not toxic and promote BAEC viability and migration.
In addition, the in vivo assay indicates that both exposition and microinjection of zebrafish embryos with Cu free MBG material increase vessel number and thickness of the subintestinal venous plexus (SIVP), whereas assays using MBG-5Cu enhance this effect.The authors gratefully acknowledge the financial support provided by the Andalusian Ministry of Economy, Science and Innovation
(Proyectos Excelencia Grants no. P10-CTS-6681 and no. P12-CTS-1507) and Spanish Ministry of Economy and Competitivity
(BIO2014-56092-R). LBRS acknowledges the CONACYT-Mexico Fellowship PhD Program
Cellular expression, trafficking, and function of two isoforms of human ULBP5/RAET1G
Background:
The activating immunoreceptor NKG2D is expressed on Natural Killer (NK) cells and subsets of T cells. NKG2D contributes to anti-tumour and anti-viral immune responses in vitro and in vivo. The ligands for NKG2D in humans are diverse proteins of the MIC and ULBP/RAET families that are upregulated on the surface of virally infected cells and tumours. Two splicing variants of ULBP5/RAET1G have been cloned previously, but not extensively characterised.
Methodology/Principal Findings:
We pursue a number of approaches to characterise the expression, trafficking, and function of the two isoforms of ULBP5/RAET1G. We show that both transcripts are frequently expressed in cell lines derived from epithelial cancers, and in primary breast cancers. The full-length transcript, RAET1G1, is predicted to encode a molecule with transmembrane and cytoplasmic domains that are unique amongst NKG2D ligands. Using specific anti-RAET1G1 antiserum to stain tissue microarrays we show that RAET1G1 expression is highly restricted in normal tissues. RAET1G1 was expressed at a low level in normal gastrointestinal epithelial cells in a similar pattern to MICA. Both RAET1G1 and MICA showed increased expression in the gut of patients with celiac disease. In contrast to healthy tissues the RAET1G1 antiserum stained a wide variety or different primary tumour sections. Both endogenously expressed and transfected RAET1G1 was mainly found inside the cell, with a minority of the protein reaching the cell surface. Conversely the truncated splicing variant of RAET1G2 was shown to encode a soluble molecule that could be secreted from cells. Secreted RAET1G2 was shown to downregulate NKG2D receptor expression on NK cells and hence may represent a novel tumour immune evasion strategy.
Conclusions/Significance:
We demonstrate that the expression patterns of ULBP5RAET1G are very similar to the well-characterised NKG2D ligand, MICA. However the two isoforms of ULBP5/RAET1G have very different cellular localisations that are likely to reflect unique functionality
Increased entropy of signal transduction in the cancer metastasis phenotype
Studies into the statistical properties of biological networks have led to
important biological insights, such as the presence of hubs and hierarchical
modularity. There is also a growing interest in studying the statistical
properties of networks in the context of cancer genomics. However, relatively
little is known as to what network features differ between the cancer and
normal cell physiologies, or between different cancer cell phenotypes. Based on
the observation that frequent genomic alterations underlie a more aggressive
cancer phenotype, we asked if such an effect could be detectable as an increase
in the randomness of local gene expression patterns. Using a breast cancer gene
expression data set and a model network of protein interactions we derive
constrained weighted networks defined by a stochastic information flux matrix
reflecting expression correlations between interacting proteins. Based on this
stochastic matrix we propose and compute an entropy measure that quantifies the
degree of randomness in the local pattern of information flux around single
genes. By comparing the local entropies in the non-metastatic versus metastatic
breast cancer networks, we here show that breast cancers that metastasize are
characterised by a small yet significant increase in the degree of randomness
of local expression patterns. We validate this result in three additional
breast cancer expression data sets and demonstrate that local entropy better
characterises the metastatic phenotype than other non-entropy based measures.
We show that increases in entropy can be used to identify genes and signalling
pathways implicated in breast cancer metastasis. Further exploration of such
integrated cancer expression and protein interaction networks will therefore be
a fruitful endeavour.Comment: 5 figures, 2 Supplementary Figures and Table
Effects of a 12-Week Global Corrective Exercise Intervention on Sway Back Posture in Young Adults: A Randomized Controlled Trial
Background: Sway back posture (SBP) is a common postural deviation of sagittal alignment and is the most common postural deviation in 18 to 28-year-old individuals, but there is no standard exercise protocol for treating SBP. Our objective was to assess the effectiveness of the global corrective exercise intervention (GCEI) on spinal posture of healthy individuals 18-25 years of age with SBP.
Methods: This study was a randomized controlled design with a parallel group, two-arm trial with 1:1 allocation ratio. Seventy participants (mean age 20.9±2.1 years) with SBP (⩾ 10°) were enrolled in the study for 12 weeks. The participants were randomly assigned to an exercise (n=35) or control group (n=35). The targeted global spine strengthening and stretching exercise intervention included core and postural training, delivered by a corrective exercise specialist in 2 groups of 20 and 15 participants 3 times a week for 12 weeks. Forward head angle and sway angle were measured using a digitized side-view photograph. Kyphosis index and llordosis index were measured using a flex curve ruler.
Results: The 12-week intervention program resulted in significant within group differences in forward head, kyphosis, lordosis and postural sway angle (p<0.001). There was also a significant between group difference in the changes of all postural variables (p<0.001).
Conclusions: The GCEI resulted in improved sway back posture in our sample of 18-25-year-old participants. This study supports the theoretical basis for clinical rehabilitation of postural deviations. Further studies are required to generalize these findings to other age and population groups.
Key words: posture, sway back, corrective exercise, spinal alignmen
Effects of a 12-Week Global Corrective Exercise Intervention on Sway Back Posture in Young Adults: A Randomized Controlled Trial
Background: Sway back posture (SBP) is a common postural deviation of sagittal alignment and is the most common postural deviation in 18 to 28-year-old individuals, but there is no standard exercise protocol for treating SBP. Our objective was to assess the effectiveness of the global corrective exercise intervention (GCEI) on spinal posture of healthy individuals 18-25 years of age with SBP.
Methods: This study was a randomized controlled design with a parallel group, two-arm trial with 1:1 allocation ratio. Seventy participants (mean age 20.9±2.1 years) with SBP (⩾ 10°) were enrolled in the study for 12 weeks. The participants were randomly assigned to an exercise (n=35) or control group (n=35). The targeted global spine strengthening and stretching exercise intervention included core and postural training, delivered by a corrective exercise specialist in 2 groups of 20 and 15 participants 3 times a week for 12 weeks. Forward head angle and sway angle were measured using a digitized side-view photograph. Kyphosis index and llordosis index were measured using a flex curve ruler.
Results: The 12-week intervention program resulted in significant within group differences in forward head, kyphosis, lordosis and postural sway angle (p<0.001). There was also a significant between group difference in the changes of all postural variables (p<0.001).
Conclusions: The GCEI resulted in improved sway back posture in our sample of 18-25-year-old participants. This study supports the theoretical basis for clinical rehabilitation of postural deviations. Further studies are required to generalize these findings to other age and population groups.
Key words: posture, sway back, corrective exercise, spinal alignmen
Impulse voltage distribution and frequency response of intershield windings
Impulse voltage distributions in continuous disk windings are nonlinear, due to the small series capacitance of the winding. Consequently, transformer manufacturers often design large power transformers with interleaved windings to increase series capacitance, but in doing so reduce the value of the initial impulse voltage distribution coefficient α given by α = √(Cg/Cs), (1) where Cg is the shunt capacitance and Cs is the series capacitance of the winding. Sometimes fully interleaved windings are employed because they are more reliable, ensuring that the transformer will operate properly under lightning strike
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