386 research outputs found
A human coronavirus responsible for the common cold massively kills dendritic cells but not monocytes
Copyright @ 2012, American Society for Microbiology.Human coronaviruses are associated with upper respiratory tract infections that occasionally spread to the lungs and other organs. Although airway epithelial cells represent an important target for infection, the respiratory epithelium is also composed of an elaborate network of dendritic cells (DCs) that are essential sentinels of the immune system, sensing pathogens and presenting foreign antigens to T lymphocytes. In this report, we show that in vitro infection by human coronavirus 229E (HCoV-229E) induces massive cytopathic effects in DCs, including the formation of large syncytia and cell death within only few hours. In contrast, monocytes are much more resistant to infection and cytopathic effects despite similar expression levels of CD13, the membrane receptor for HCoV-229E. While the differentiation of monocytes into DCs in the presence of granulocyte-macrophage colony-stimulating factor and interleukin-4 requires 5 days, only 24 h are sufficient for these cytokines to sensitize monocytes to cell death and cytopathic effects when infected by HCoV-229E. Cell death induced by HCoV-229E is independent of TRAIL, FasL, tumor necrosis factor alpha, and caspase activity, indicating that viral replication is directly responsible for the observed cytopathic effects. The consequence of DC death at the early stage of HCoV-229E infection may have an impact on the early control of viral dissemination and on the establishment of long-lasting immune memory, since people can be reinfected multiple times by HCoV-229E
CAM LiF KATKISININ BETON DAYANIMINA ETKiSİ
Bu 9ahjmada, %0.2, 0.4 ve 0.6 aglfhk oranlannda earn liflerle katkllandmlmlj beton matrisli kompozit
malzemenin mekanik davranJ~lafl aramm
belirlenmesi, 09 nokta ve dart nokta egilme deneyleri ile geryekle~tirilmi~tjr. Cam litlerle katkllandlfllanbetonun
gekme ve egilme dayammlarmm arttlgl, basm9 mukavemetinin ise azaldlgl yapilan deneylerde tespit edilmijtir.
09 nokta egilme deneyleri ile elde edilen mukavemet sonu9larmm, d6rt nokta egilmeye g6re daha yUksek oldugu
g6zlenmijtir. Beton matrisi katkllandlfan earn litler, matris igerisinde homojen olarak yayilmlj bir donatl gibi
9ahjarak, U9boyutlu bir mikro takviye vazifesi g6rmUjlerdir. Basmy deneyi slrasmda bOjluk gibi davranan bu
lifler basll1ydayammmJ di.i$tirmU~lerdir
Vibrational properties of SrCu2O2 studied via Density Functional Theory calculations and compared to Raman and infrared spectroscopy measurements
International audienceThe SrCu2O2 material is a p-type transparent conductive oxide. A theoretical study of the SrCu2O2 crystal is performed with a state of the art implementation of the Density Functional Theory. The simulated crystal structure is compared with available X-ray diffraction data and previous theoretical modeling. Density Functional Perturbation Theory is used to study the vibrational properties of the SrCu2O2 crystal. A symmetry analysis of the optical phonon eigenvectors at the Brillouin zone center is proposed. The Raman spectra simulated using the derivatives of the dielectric susceptibility, show a good agreement with Raman scattering experimental results
Improvement of Mechanical Properties of Reinforcing Steel Used in the Reinforced Concrete Structures
SAEIOIO structural carbon steel, which has a low cost price and wide range of use in the construction industry,
has been studied as dual phase (DP) steel subjected to appropriate heat treatment, and its mechanical properties
have been investigated under various tempering conditions. Intercritical annealing heat treatment has been applied
to the reinforcing steel in order to obtain DP steels with different martensite volume fraction. In addition, these DP
steels have been tempered at 200, 300 and 400 'C for 45 min and then cooled to the room temperature. Mechanical
properties such as tensile strength, yield strength, reduction in cross-sectional area, total elongation, resilience modulus
and toughness have been examined. Furthermore, fractographic examination has been done with scanning electron
microscope (SEM) as well as metallographic examination of the steels. As a result of this study, it is found that
mechanical properties of DP steel have changed according to the hardness and ratio of martensite phase. In addition,
tensile strength, yield strength and resilience modulus of the steels have been reduced. In contrast, the total elongation,
reduction of the cross-sectional area and toughness have been increased
A study on dynamic modulus of self-consolidating rubberized concrete
In this study, dynamic modulus of elasticity of self-consolidating rubberized concrete is
evaluated by using results of ultrasonic pulse velocity and resonance frequency tests. Additionally, correlation between dynamic modulus of elasticity and compressive strength results is compared. For evaluating the dynamic modulus of elasticity of self-consolidating rubberized concrete, prismatic specimens having 100 x 100 x 500 mm dimensions are prepared. Dynamic modulus of elasticity values obtained by non-destructive measurements techniques are well agreed with those given in the literature
"Improvement of Mechanical Properties of Reinforcing Steel Used in the Reinforced Concrete Structures"
SAEIOIO structural carbon steel, which has a low cost price and wide range of use in the construction industry,
has been studied as dual phase (DP) steel subjected to appropriate heat treatment, and its mechanical properties
have been investigated under various tempering conditions. Intercritical annealing heat treatment has been applied
to the reinforcing steel in order to obtain DP steels with different martensite volume fraction. In addition, these DP
steels have been tempered at 200, 300 and 400 'C for 45 min and then cooled to the room temperature. Mechanical
properties such as tensile strength, yield strength, reduction in cross-sectional area, total elongation, resilience modulus
and toughness have been examined. Furthermore, fractographic examination has been done with scanning electron
microscope (SEM) as well as metallographic examination of the steels. As a result of this study, it is found that
mechanical properties of DP steel have changed according to the hardness and ratio of martensite phase. In addition,
tensile strength, yield strength and resilience modulus of the steels have been reduced. In contrast, the total elongation,
reduction of the cross-sectional area and toughness have been increased
THERMODYNAMICS OF A BROWNIAN BRIDGE POLYMER MODEL IN A RANDOM ENVIRONMENT
We consider a directed random walk making either 0 or moves and a
Brownian bridge, independent of the walk, conditioned to arrive at point on
time . The Hamiltonian is defined as the sum of the square of increments of
the bridge between the moments of jump of the random walk and interpreted as an
energy function over the bridge connfiguration; the random walk acts as the
random environment. This model provides a continuum version of a model with
some relevance to protein conformation. The thermodynamic limit of the specific
free energy is shown to exist and to be self-averaging, i.e. it is equal to a
trivial --- explicitly computed --- random variable. An estimate of the
asymptotic behaviour of the ground state energy is also obtained.Comment: 20 pages, uuencoded postscrip
Do Peripheral and Extra Musculoskeletal Manifestations Have An Impact on Biologic Dmard Prescribing Patterns in Axial Spondyloarthritis: the Results of Treasure Experience
[No Abstract Available
The antioxidant vitamin E modulates amyloid b-peptid-induced creatine kinase activity inhibition and increased protein oxidation: Implications for the free radical hypothesis of Alzheimer’s disease
Amyloid B-peptide (AB), the main constituent of senile plaques in Alzheimer's disease (AD) brain, is hypothesized to be a key factor in the neurodegeneration seen in AD. Recently it has been shown by us and others that the neurotoxicity of AB occurs in conjunction with free radical oxidative stress associated with the peptide. AB(1-40) and several other fragments of the AB sequence are associated with free radicals in solution that are detectable using electron paramagnetic resonance spectroscopy. These free radicals were shown to attack brain cell membranes, initiate lipid peroxidation, increase Ca 2+ influx and damage membrane and cytosolic proteins. In AD brain obtained under rapid autopsy protocol, the activity of the oxidatively-sensitive enzyme creatine kinase was shown to be significantly reduced. We reasoned that AB-associated free radical-induced modification of creatine kinase activity and other markers of cellular damage might be modulated by free radical scavengers. Accordingly, this study demonstrates that vitamin E can modulate AB(25-35)-induced oxidative damage to creatine kinase and cellular proteins in cultured embryonic hippocampal neurons. These results, consistent with the hypothesis of free radical-mediated AB toxicity in AD, are discussed with deference to potential free radical scavengers as therapeutic agents for slowing the progression of AD
Bond Performance of the Rubber particles in the Self-Compacting Concrete
Generating more ductile concrete elements by using waste tire rubbers have been studied for
thirty years. Researchers have been produced a lot of rubberized concrete from low strength structure applications
to self-compacting concretes having high strength and durability. It is possible to have more flexible
concrete while using the fiber shaped waste tire rubbers. Critical problem of use of these rubbers is poor adherence
between rubbers and cement paste interface. It is assumed that use of pozzolans with the Portland cement
will fix this adherence problem. Therefore, waste tire rubbers have been studied in the self-compacting
concrete in order to enhance the problem. Portland cement, grand granulated furnace slag and pozzolanic cement
were used together for preparing the self-compacting concretes. Bonding performances of waste tire
rubbers and reinforced bars in the self-compacting rubberized concrete were investigated experimentally in
this study
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