146 research outputs found
Interplay of fission modes in mass distribution of light actinide nuclei 225,227Pa
Fission-fragment mass distributions were measured for 225,227Pa nuclei formed
in fusion reactions of 19F + 206, 208Pb around fusion barrier energies.
Mass-angle correlations do not indicate any quasi-fission like events in this
bombarding energy range. Mass distributions were fitted by Gaussian
distribution and mass variance extracted. At below-barrier energies, the mass
variance was found to increase with decrease in energy for both nuclei. Results
from present work were compared with existing data for induced fission of 224,
226Th and 228U around barrier energies. Enhancement in mass variance of 225,
227Pa nuclei at below-barrier energies shows evidence for presence of
asymmetric fission events mixed with symmetric fission events. This is in
agreement with the results of mass distributions of nearby nuclei 224, 226Th
and 228U where two-mode fission process was observed. Two-mode feature of
fission arises due to the shell effects changing the landscape of the potential
energy surfaces at low excitation energies. The excitation-energy dependence of
the mass variance gives strong evidence for survival of microscopic shell
effects in fission of light actinide nuclei 225, 227Pa with initial excitation
energy ~30 - 50 MeV
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The Quorum Sensing Volatile Molecule 2-Amino Acetophenon Modulates Host Immune Responses in a Manner that Promotes Life with Unwanted Guests
Increasing evidence indicates that bacterial quorum sensing (QS) signals are important mediators of immunomodulation. However, whether microbes utilize these immunomodulatory signals to maintain infection remain unclear. Here, we show that the Pseudomonas aeruginosa QS-regulated molecule 2-amino acetophenone (2-AA) modulates host immune responses in a manner that increases host ability to cope with this pathogen. Mice treated with 2-AA prior to infection had a 90% survival compared to 10% survival rate observed in the non-pretreated infected mice. Whilst 2-AA stimulation activates key innate immune response pathways involving mitogen-activated protein kinases (MAPKs), nuclear factor (NF)-, and pro-inflammatory cytokines, it attenuates immune response activation upon pretreatment, most likely by upregulating anti-inflammatory cytokines. 2-AA host pretreatment is characterized by a transcriptionally regulated block of c-JUN N-terminal kinase (JNK) and NF- activation, with relatively preserved activation of extracellular regulated kinase (ERK) 1/2. These kinase changes lead to CCAAT/enhancer-binding protein- activation and formation of the complex that prevents NF- activation. 2-AA's aptitude for dampening the inflammatory processes while increasing host survival and pathogen persistence concurs with its ability to signal bacteria to switch to a chronic infection mode. Our results reveal a QS immunomodulatory signal that promotes original aspects of interkingdom communication. We propose that this communication facilitates pathogen persistence, while enabling host tolerance to infection
Analysis of phytochemical constituents and antibacterial activity of Wrightia tinctoria: traditional medicinal plant of India for application on wound dressing materials
48-54Wrightia tinctoria, an important traditional medicinal plant is exploited for treating several diseases. The study intends to reveal the presence of phytochemicals and test the antibacterial activity of W. tinctoria leaf extracts on nonwoven fabrics to find its suitability for wound dressings. The methodology includes identification and collection of W. tinctoria leaves, preparation of leaf powder, determination of physicochemical analysis, extraction using different solvents, preliminary phytochemical screening, quantitative estimation of phytoconstituents, yield of the extracts and determination of antibacterial activity on plant extract treated fabrics. Results revealed the presence of more active metabolites in the ethanol plant extract of W. tinctoria leaves which may be the reason for the promising antibacterial potential against the bacterial strains. As a promising ethnomedicinal plant, W. tinctoria may serve as a major source of useful drugs finding its suitability for developing wound dressings
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Nuclear magnetic resonance in conjunction with functional genomics suggests mitochondrial dysfunction in a murine model of cancer cachexia
Cancer patients commonly suffer from cachexia, a syndrome in which tumors induce metabolic changes in the host that lead to massive loss in skeletal muscle mass. Using a preclinical mouse model of cancer cachexia, we tested the hypothesis that tumor inoculation causes a reduction in ATP synthesis and genome-wide aberrant expression in skeletal muscle. Mice implanted with Lewis lung carcinomas were examined by in vivo 31P nuclear magnetic resonance (NMR). We examined ATP synthesis rate and the expression of genes that play key-regulatory roles in skeletal muscle metabolism. Our in vivo NMR results showed reduced ATP synthesis rate in tumor-bearing (TB) mice relative to control (C) mice, and were cross-validated with whole genome transcriptome data showing atypical expression levels of skeletal muscle regulatory genes such as peroxisomal proliferator activator receptor γ coactivator 1 ß (PGC-1ß), a major regulator of mitochondrial biogenesis and, mitochondrial uncoupling protein 3 (UCP3). Aberrant pattern of gene expression was also associated with genes involved in inflammation and immune response, protein and lipid catabolism, mitochondrial biogenesis and uncoupling, and inadequate oxidative stress defenses, and these effects led to cachexia. Our findings suggest that reduced ATP synthesis is linked to mitochondrial dysfunction, ultimately leading to skeletal muscle wasting and thus advance our understanding of skeletal muscle dysfunction suffered by cancer patients. This study represents a new line of research that can support the development of novel therapeutics in the molecular medicine of skeletal muscle wasting. Such therapeutics would have wide-spread applications not only for cancer patients, but also for many individuals suffering from other chronic or endstage diseases that exhibit muscle wasting, a condition for which only marginally effective treatments are currently available
Disparities and relative risk ratio of preterm birth in six Central and Eastern European centers
Aim To identify characteristic risk factors of preterm birth
in Central and Eastern Europe and explore the differences
from other developed countries.
Method Data on 33 794 term and 3867 preterm births
(<37 wks.) were extracted in a retrospective study between
January 1, 2007 and December 31, 2009. The study took
place in 6 centers in 5 countries: Czech Republic, Hungary
(two centers), Romania, Slovakia, and Ukraine. Data on historical
risk factors, pregnancy complications, and special
testing were gathered. Preterm birth frequencies and relevant
risk factors were analyzed using Statistical Analysis
System (SAS) software.
Results All the factors selected for study (history of smoking,
diabetes, chronic hypertension, current diabetes,
preeclampsia, progesterone use, current smoking, body
mass index, iron use and anemia during pregnancy), except
the history of diabetes were predictive of preterm
birth across all participating European centers. Preterm
birth was at least 2.4 times more likely with smoking (history
or current), three times more likely with preeclampsia,
2.9 times more likely with hypertension after adjusting for
other covariates. It had inverse relationship with the significant
predictor body mass index, with adjusted risk ratio of
0.8 to 1.0 in three sites. Iron use and anemia, though significant
predictors of preterm birth, indicated mixed patterns
for relative risk ratio.
Conclusion Smoking, preeclampsia, hypertension and
body mass index seem to be the foremost risk factors of
preterm birth. Implications of these factors could be beneficial
for design and implementation of interventions and
improve the birth outcome
Chiral symmetry in linear Sigma model in magnetic environment
We study the chiral symmetry structure in a linear sigma model with fermions
in the presence of an external, uniform magnetic field in the 'effective
potential' approach at the one loop level. We also study the chiral phase
transition as a function of density in the core of magnetized neutron stars.Comment: LaTex2e file with six postscript figures. journal ref: Physical
Review D 62 (2000) 02502
Nuclear magnetic resonance in conjunction with functional genomics suggests mitochondrial dysfunction in a murine model of cancer cachexia
Cancer patients commonly suffer from cachexia, a syndrome in which tumors induce metabolic changes in the host that lead to massive loss in skeletal muscle mass. Using a preclinical mouse model of cancer cachexia, we tested the hypothesis that tumor inoculation causes a reduction in ATP synthesis and genome-wide aberrant expression in skeletal muscle. Mice implanted with Lewis lung carcinomas were examined by in vivo 31P nuclear magnetic resonance (NMR). We examined ATP synthesis rate and the expression of genes that play key-regulatory roles in skeletal muscle metabolism. Our in vivo NMR results showed reduced ATP synthesis rate in tumor-bearing (TB) mice relative to control (C) mice, and were cross-validated with whole genome transcriptome data showing atypical expression levels of skeletal muscle regulatory genes such as peroxisomal proliferator activator receptor γ coactivator 1 ß (PGC-1ß), a major regulator of mitochondrial biogenesis and, mitochondrial uncoupling protein 3 (UCP3). Aberrant pattern of gene expression was also associated with genes involved in inflammation and immune response, protein and lipid catabolism, mitochondrial biogenesis and uncoupling, and inadequate oxidative stress defenses, and these effects led to cachexia. Our findings suggest that reduced ATP synthesis is linked to mitochondrial dysfunction, ultimately leading to skeletal muscle wasting and thus advance our understanding of skeletal muscle dysfunction suffered by cancer patients. This study represents a new line of research that can support the development of novel therapeutics in the molecular medicine of skeletal muscle wasting. Such therapeutics would have wide-spread applications not only for cancer patients, but also for many individuals suffering from other chronic or endstage diseases that exhibit muscle wasting, a condition for which only marginally effective treatments are currently available
Thermal Activation of Methane by MgO+: Temperature Dependent Kinetics, Reactive Molecular Dynamics Simulations and Statistical Modeling
The kinetics of MgO + + CH 4 was studied experimentally using the variable ion source, temperature adjustable selected ion flow tube (VISTA-SIFT) apparatus from 300 − 600 K and computationally by running and analyzing reactive atomistic simula- tions. Rate coefficients and product branching fractions were determined as a function of temperature. The reaction proceeded with a rate of k = 5 . 9 ± 1 . 5 × 10 − 10 ( T/ 300 K) − 0 . 5 ± 0 . 2 cm 3 s − 1 . MgOH + was the dominant product at all temperatures, but Mg + , the co-product of oxygen-atom transfer to form methanol, was observed with a product branching fraction of 0 . 08 ± 0 . 03( T/ 300 K) − 0 . 8 ± 0 . 7 . Reactive molecular dynamics simulations using a reactive force field, as well as a neural network trained on thousands of structures yield rate coefficients about one order of magnitude lower. This underestimation of the rates is traced back to the multireference character of the transition state [MgOCH 4 ] + . Statistical modeling of the temperature-dependent kinetics provides further insight into the reactive potential surface. The rate limiting step was found to be consistent with a four-centered activation of the C-H bond, consistent with previous calculations. The product branching was modeled as a competition between dissociation of an insertion intermediate directly after the rate- limiting transition state, and traversing a transition state corresponding to a methyl migration leading to a Mg-CH 3 OH + complex, though only if this transition state is stabilized significantly relative to the dissociated MgOH + + CH 3 product channel. An alternative non-statistical mechanism is discussed, whereby a post-transition state bifurcation in the potential surface could allow the reaction to proceed directly from the four-centered TS to the Mg-CH 3 OH + complex thereby allowing a more robust competition between the product channels
Symmetry structure and phase transitions
We study chiral symmetry structure at finite density and temperature in the
presence of external magnetic field and gravity, a situation relevant in the
early Universe and in the core of compact stars.
We then investigate the dynamical evolution of phase transition in the
expanding early Universe and possible formation of quark nuggets and their
survival.Comment: Plenary talk given at the 4th. ICPAQGP held at Jaipur, India from Nov
26-30, 2001.laTex 2e file with 8 ps figures and 12 page
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