3,032 research outputs found
Molecular imaging of atherosclerosis with integrated PET imaging
Atherosclerotic diseases account for nearly half of all deaths and are leading causes of adult disability. Our understanding of how atherosclerosis leads to cardiovascular disease events has evolved: from a concept of progressive luminal narrowing, to that of sudden rupture and thrombosis of biologically active atheroma. In concert with this conceptual shift, contemporary imaging techniques now allow imaging of biological processes that associate with plaque instability: active calcification and plaque inflammation. This review focuses on opportunities provided by positron emission tomography/computed tomography, to identify these high-risk biological features of atherosclerosis.BH is supported by Research Training grant from Alexandria University. NRE is supported by a Research Training Fellowship from The Dunhill Medical Trust [Grant Number RTF44/0114]. JHFR is part supported by the NIHR Cambridge Biomedical Research Centre, the British Heart Foundation, EPSRC, and the Wellcome Trust. AT reports grants from NIH/NHLBI, Actelion, Genentech and Takeda, and personal fees from Actelion, Amgen AstraZeneca, and Takeda, all outside the submitted work
Visualization of Some Energy Levels of Even-Even Nuclei
The properties of the lowest excited states of atomic nuclei offer a very sensitive test for nuclear structure theories. To identify and distinguish the shape phase transitions, one needs the variation behaviors of the energy ratios with respect to the neutron or proton number of the nuclei. The possibility of generating images of the variation behaviors of energy levels and energy ratios by exploiting the large body of data on stable and near-stable nuclei, whose accumulation over the past decades now permits, prompted us to produce this atlas which illustrates in a simple and effective way these behaviors. The atlas represents the experimental data of the energy levels and energy ratios of the 2_1^+, 4_1^+, 2_2^+ and 4_2^+ states of 645 even-even nuclei. The interpolation surfaces of the values of energy levels and energy ratios, E(2,1+), E(2,2+), E(4,1+), E(4,2+), E(4,1+)/E(2,1+), E(4,2+)/E(2,2+), E(2,2+)/E(2,1+), E(4,2+)/E(4,1+), E(4,2+)/E(2,1+) and E(4,1+)/E(2,2+), through all points of the even-even nuclear landscape are presented. The variation of these values with respect to each chain of isotopes and isotones are displayed using two-dimensional figures. Visualization of the data through visual imagery has been considered an effective way for connecting abstract and concrete ideas as well as allowing the emergence of the significant patterns. Moreover, we will see that it is possible, in many if not most cases, to understand the detailed results of complex calculations of the nuclear structure theories with an absolute minimum of formalism and often by inspection. The introduction of this atlas contains a brief account of some topics of present-day interest in theoretical nuclear structure. These topics can be used to explain the existence of a few typical patterns of nuclear spectra as well as some of the systematic changes in these patterns over sequences of nuclei. Researchers working on nuclear theory will find this atlas handy to understand the nuclear structure theories
High-Performance Modeling and Simulation of Anchoring in Granular Media for NEO Applications
NASA is interested in designing a spacecraft capable of visiting a near-Earth object (NEO), performing experiments, and then returning safely. Certain periods of this mission would require the spacecraft to remain stationary relative to the NEO, in an environment characterized by very low gravity levels; such situations require an anchoring mechanism that is compact, easy to deploy, and upon mission completion, easy to remove. The design philosophy used in this task relies on the simulation capability of a high-performance multibody dynamics physics engine. On Earth, it is difficult to create low-gravity conditions, and testing in low-gravity environments, whether artificial or in space, can be costly and very difficult to achieve. Through simulation, the effect of gravity can be controlled with great accuracy, making it ideally suited to analyze the problem at hand. Using Chrono::Engine, a simulation pack age capable of utilizing massively parallel Graphic Processing Unit (GPU) hardware, several validation experiments were performed. Modeling of the regolith interaction has been carried out, after which the anchor penetration tests were performed and analyzed. The regolith was modeled by a granular medium composed of very large numbers of convex three-dimensional rigid bodies, subject to microgravity levels and interacting with each other with contact, friction, and cohesional forces. The multibody dynamics simulation approach used for simulating anchors penetrating a soil uses a differential variational inequality (DVI) methodology to solve the contact problem posed as a linear complementarity method (LCP). Implemented within a GPU processing environment, collision detection is greatly accelerated compared to traditional CPU (central processing unit)- based collision detection. Hence, systems of millions of particles interacting with complex dynamic systems can be efficiently analyzed, and design recommendations can be made in a much shorter time. The figure shows an example of this capability where the Brazil Nut problem is simulated: as the container full of granular material is vibrated, the large ball slowly moves upwards. This capability was expanded to account for anchors of different shapes and penetration velocities, interacting with granular soils
Spontaneous regression of a primary squamous cell lung cancer following biopsy: a case report
Background: Spontaneous regression has been defined as occurring when the malignant tumor mass partially or completely disappears without any treatment or as a result of a therapy considered inadequate to influence systemic neoplastic disease. Recently, studies have implicated immunological responses as likely being involved. We report a case of a patient with squamous cell carcinoma of the lung who experienced spontaneous regression following biopsy without other intervention.
Case Presentation: A 57-year-old white man was referred to our pulmonary clinic after an incidental finding of a nodule in the lower lobe of his left lung. Thoracic computed tomography revealed a 2.0 × 1.4 × 1.5 cm spiculated nodule in the superior segment of the left lower lobe. Workup identified the mass as a squamous cell carcinoma that was clinically staged as T1M0N0. The patient deferred treatment of this lesion. He undertook no significant lifestyle or medical changes. Three months later, computed tomography revealed that, compared with the initial study, the solitary mass had decreased in size to 1.6 × 0.9 × 0.9 cm. Follow-up computed tomography 1 year after the original workup demonstrated that the nodule had stabilized to its smaller size.
Conclusions: Studies have shown that immunological response can be initiated by trauma to an area. Because the tumor regression became evident in our patient only after the tissue biopsy, his immune response to the surgical procedure seems to be a plausible contributor to the spontaneous regression. Further understanding of spontaneous regression can potentially impact the identification of neoplastic drug targets or even the course of a patient\u27s treatment plan and goals
The accuracy of currently used WHO´s Body Mass Index cut-off points to measure Overweight and Obesity in Syrian women: A correlation study
Purpose: Obesity is a common health problem in both developed and developing countries. BMI is commonly used to identify obesity. However, there is increasing evidence that the relationship between BMI and BF% differs among various ethnicities. The main objectives of this study are (1) to evaluate the correlation between BF% as determined by BIA, DEXA, Deuterium oxide (D2O) and BMI, (2) to assess the accuracy of currently used WHOÅLs BMI cut-off points to identify overweight and obesity among Syrian women.
Material and Methods: A total of 908 healthy Syrian women aged 18-60 years participated in this study. Weight, height, BMI, BF% assessed by BIA and DEXA, and D2O have been determined.
Results: BF% results obtained by BIA and DEXA, and D2O revealed strong correlations. BMI showed a statistically significant correlation with BF% determined by BIA, DEXA and D2O. Obesity when defined as BMI ≥ 30 and as BF% > 35% (derived from BIA, DEXA and D2O) classified 43%, 52.5%, 75.9% and 72.7% of women as obese, respectively. ROC analysis defined BMI cut-off points for overweight and obesity of 22.5 and 25.7, respectively. Using the new BMI cut-off point, the prevalence of obesity among Syrian women was increased by 24%.
Conclusions: The current BMI cut-off points recommended by WHO underestimate the prevalence of overweight and obesity among Syrian women. Our data suggests that it is important to lower the proposed WHOÅLs BMI cut-off points for the Syrian women
An integrated approach of building information modelling and life cycle assessment (BIM-LCA) for gas and solar water heating systems
Buildings are responsible for the energetic consumption and potential greenhouse gas emissions during their life cycle. Water heating system contribute to a building’s energetic consumption, mainly in residential units, throughout the building’s operational phase. Variability in energy sources, reservation and distribution systems of hot water along with the types of construction materials used in these building systems are key decisions to make in the initial design phases of a building project. Often, the definition of the most appropriate water heating system for a building is made via a technical-economic decision. However, the decision is rarely based on natural resource consumption and environmental impact generation throughout the life-cycle of the heating systems and of buildings as a whole. This study presents an application of a specific environmental management tool, based on an integrated Building Information Modelling (BIM) and Life-Cycle Analysis (LCA) method for selection of hot water systems, during the early design building phase. The proposed approach is implemented in the pre-operational phase, in order to enable decision makers to appreciate the resulting environmental performance of water heating systems in buildings. The applicability of the framework is tested via a comparative study of solar heating water systems and natural gas heating water systems for a residential multifamily building to be constructed in Rio de Janeiro, Brazil. For the indicators damage to human health and damage to ecosystem, results indicate that the greatest impact on global warming comes from the natural gas heating system, while for solar heating, free particulate matter was the highest negative contribution. The operation phase for the natural gas system was highest for climate change while for solar heating system, it was the fresh water that was impacted the most during the pre-operational phase of the system’s use
Expression of TLR-2 in hepatocellular carcinoma is associated with tumour proliferation, angiogenesis and Caspase-3 expression
Aims:
Unlike other Toll-like receptors (TLRs), the role of toll like receptor 2 (TLR-2) in the pathogenesis of chronic liver disease and hepatocellular carcinoma (HCC) is not well studied. We, therefore, set out to investigate the expression of TLR-2 in different chronic liver disease states along with other markers of cell death, cellular proliferation and tissue vascularisation
Methods and results:
Immunohistochemistry was performed on liver tissue microarrays comprising hepatitis, cirrhosis and HCC patient samples using antibodies against TLR-2, Ki-67, Caspase-3 and VEGF. This was done in order to characterise receptor expression and translocation, apoptosis, cell proliferation and vascularisation. Cytoplasmic TLR-2 expression was found to be weak in 5/8 normal liver cases, 10/19 hepatitis cases and 8/21 cirrhosis patients. Moderate to strong TLR-2 expression was observed in some cases of hepatitis and cirrhosis. Both, nuclear and cytoplasmic TLR-2 expression was present in HCC with weak intensity in 11/41 cases, and moderate to strong staining in 19/41 cases. Eleven HCC cases were TLR-2 negative. Surprisingly, both cytoplasmic and nuclear TLR-2 expression in HCC were found to significantly correlate with proliferative index (r = 0.24 and 0.37), Caspase-3 expression (r = 0.27 and 0.38) and vascularisation (r = 0.56 and 0.23). Further, nuclear TLR-2 localisation was predominant in HCC, whereas cytoplasmic expression was more prevalent in hepatitis and cirrhosis. Functionally, treatment of HUH7 HCC cells with a TLR-2 agonist induced the expression of cellular proliferation and vascularisation markers CD34 and VEGF.
Conclusions:
Our results demonstrate a positive correlation between the expression of TLR-2 and other markers of proliferation and vascularisation in HCC which suggests a possible role for TLR-2 in HCC pathogenesi
Entropy, time irreversibility and Schroedinger equation in a primarily discrete space-time
In this paper we show that the existence of a primarily discrete space-time
may be a fruitful assumption from which we may develop a new approach of
statistical thermodynamics in pre-relativistic conditions. The discreetness of
space-time structure is determined by a condition that mimics the Heisenberg
uncertainty relations and the motion in this space-time model is chosen as
simple as possible. From these two assumptions we define a path-entropy that
measures the number of closed paths associated with a given energy of the
system preparation. This entropy has a dynamical character and depends on the
time interval on which we count the paths. We show that it exists an
like-equilibrium condition for which the path-entropy corresponds exactly to
the usual thermodynamic entropy and, more generally, the usual statistical
thermodynamics is reobtained. This result derived without using the Gibbs
ensemble method shows that the standard thermodynamics is consistent with a
motion that is time-irreversible at a microscopic level. From this change of
paradigm it becomes easy to derive a . A comparison with the
traditional Boltzmann approach is presented. We also show how our approach can
be implemented in order to describe reversible processes. By considering a
process defined simultaneously by initial and final conditions a well defined
stochastic process is introduced and we are able to derive a Schroedinger
equation, an example of time reversible equation.Comment: latex versio
Enhanced heterogeneous activation of peroxymonosulfate by Ruddlesden-Popper-type La2CoO4+δ nanoparticles for bisphenol A degradation
The scalable synthesis of stable catalysts for environmental remediation applications remains challenging. Nonetheless, metal leaching is a serious environmental issue hindering the practical application of transition-metal based catalysts including Co-based catalysts. Herein, for the first time, we describe a facile one-step and scalable spray-flame synthesis of high surface area La2CoO4+δ nanoparticles containing excess oxygen interstitials (+δ) and use them as a stable and efficient catalyst for activating peroxymonosulfate (PMS) towards the degradation of bisphenol A. Importantly, the La2CoO4+δ catalyst exhibits higher catalytic degradation of bisphenol A (95% in 20 min) and stability than LaCoO3–x nanoparticles (60%) in the peroxymonosulfate activation system. The high content of Co2+ in the structure showed a strong impact on the catalytic performance of the La2CoO4+δ + PMS system. Despite its high specific surface area, our results showed a very low amount of leached cobalt (less than 0.04 mg/L in 30 min), distinguishing it as a material with high chemical stability. According to the radical quenching experiments and the electron paramagnetic resonance technology, SO4[rad]–, [rad]OH, and 1O2 were generated and SO4[rad]– played a dominant role in bisphenol A degradation. Moreover, the La2CoO4+δ + PMS system maintained conspicuous catalytic performance for the degradation of other organic pollutants including methyl orange, rhodamine B, and methylene blue. Overall, our results showed that we developed a new synthesis method for stable La2CoO4+δ nanoparticles that can be used as a highly active heterogeneous catalyst for PMS-assisted oxidation of organic pollutants
Lipopolysaccharide-induced suppression of airway Th2 responses does not require IL-12 production by dendritic cells
The prevalence of atopic asthma, a Th2-dependent disease, is reaching
epidemic proportions partly due to improved hygiene in industrialized
countries. There is an inverse correlation between the level of
environmental endotoxin exposure and the prevalence of atopic
sensitization. As dendritic cells (DC) have been implicated in causing
sensitization to inhaled Ag, we studied the effect of endotoxin on Th2
development induced by bone marrow DC in vitro and by intratracheal
injection in vivo, with particular emphasis on the role played by the
polarizing cytokine IL-12. Bone marrow-derived DC stimulated with
Escherichia coli O26:B6 LPS produced IL-12p70 for a limited period of
time, after which production became refractory to further stimulation with
CD40 ligand, a phenomenon previously called "exhaustion." The level of
IL-12 production of DC did not correlate with Th1 development, as
exhausted OVA-pulsed DC were still capable of shifting the cytokine
pattern of responding OVA-specific Th cells toward Th1 in vitro and in
vivo. When mice were first immunized by intratracheal injection of OVA-DC
and subsequently challenged with OVA aerosol, prior in vitro stimulation
of DC with LPS reduced the development of airway eosinophilia and Th2
cytokine production. Most surprisingly, the capacity of LPS to reduce
Th2-dependent eosinophilic airway inflammation was IL-12-independent
altogether, as IL-12p40 knockout DC had a similar reduced capacity to
prime for Th2 responses. These results suggest that LPS reduces
sensitization to inhaled Ag by reducing DC-driven Th2 development, but
that IL-12 is not necessary for this effect
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