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This work presents several results of the stability in steel columns subject to pure compression. A square hollow cross-section with different sizes was considered. This study presents all the analytical equations that need to be used to verify the stability of each column with different lengths and boundary conditions. A finite element program was also chosen to achieve the most critical loads (Euler and buckling resistance loads) in the calculation for each element under study, using linear and nonlinear geometric and material modeling. Steel material was used for the columns, where damage due to plasticity was included, through plastic behavior with isotropic hardening. Comparing the results allows us to conclude that the use of the finite element method is an alternative methodology to be used in other types or configurations of columns, where parameterized tests can be easily implemented and to contribute to the development of a wide-ranging database. The finite element method led to an accurate solution when compared with the analytical results with a maximum deviation of 14.7%. By increasing the column length and reducing the cross-section size, the design buckling resistance of the studied columns also decreases. These studies demonstrate that the length and size of the column cross-section can meaningfully increase the structural behavior of the columns. [ABSTRACT FROM AUTHOR]

We conducted a comparative study on chemical composition of organic aerosols (OA) collected in urban and marine atmosphere, respectively, using three mass spectrometers, Filter Inlet for Gases and Aerosol-Iodide-Chemical Ionization Mass Spectrometry (FIGAERO-I-CIMS), Electrospray Ionization-Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (ESI-FT-ICR MS), and Two-dimensional Gas Chromatograph-Electron Ionization-Mass Spectrometry (GC × GC-EI-ToF-MS). The FIGAERO-I-CIMS, ESI(–)-FT-ICR MS, and ESI(+)-FT-ICR MS showed preferred sensitivity to CHO, CHOS/CHONS, and CHON compounds, respectively. The compounds detected by the FIGAERO-I-CIMS were more oxidized and saturated than those detected by the ESI-FT-ICR MS. The GC × GC-EI-ToF-MS offered the advantage of detecting organonitrates, carbonyls, alkanes, oxy-PAHs, and amides in OA. Despite different MS technologies, some distinct features of organic compound distribution were observed between urban and marine OA. CHON compounds were more abundant in urban aerosols than marine aerosols. Organonitrates dominated over reduced-nitrogen organic compounds in all samples, and the relative importance of aromatic and aliphatic nitrates depended on MS technologies and sample type. The contribution of CHOS/CHONS compounds was high (25.1%–66.2%) in urban aerosols or marine aerosols being heavily influenced by continental sources. The most important CHOS/CHONS type in these samples were organosulfates of biogenic origin (49.4%–62.9%). Aromatics-like organosulfates contributed the least (9.1%–21.2%) to total intensity of CHOS/CHONS compounds. Considering high proportion (34.4%–62.8%) of aromatics-like compounds in OA, our result indicated that aromatic compounds were less prone to form organosulfates than aliphatic compounds. More Chlorine-containing compounds were found in clean urban atmosphere than polluted urban atmosphere. Most of Chlorine-containing compounds in urban aerosols were aliphatic, while those in marine aerosols were mostly aromatic. This study demonstrated the necessity of employing multiple MS technologies for a better characterization of chemical composition of complex organic aerosols. Copyright © 2024 American Association for Aerosol Research [ABSTRACT FROM AUTHOR]

Background: We aimed to study the presence of anti-2-glycoprotein I antibodies (anti-2GPI) in patients with systemic lupus erythematosus (SLE) analyzing their relationship with anticardiolipin antibodies (aCL)., Patients and Method: 63 patients with SLE and 54 healthy volunteers. Detection of anti-2GPI antibodies was performed by ELISA., Results: 25 (40%) patients with SLE and 1 (2%) control had anti-2GPI antibodies (p < 0.001). 17 patients with aCL (43%) had anti-2GPI antibodies and 4 patients (20%) without aCL were found to have anti-2GPI antibodies (p < 0.05). There was an association between thrombosis and aCL. However, the association between thrombosis and anti-2GPI antibodies was not significant., Conclusions: Anti-2GPI antibodies are more frequent in SLE and they are more prevalent in patients with aCL. There is an association between thrombosis and aCL but no significant association between thrombosis and anti-2GPI antibodies.

Objectives: a) to determine the prevalence of anti-ribosomal P antibodies in patients with ESL in our setting; b) to determine if there are associations between clinical signs of ESL and these autoantibodies; c) to analyze if there is any correlation between the presence of anti-P in patients with ESL and the results of other routine lab tests; and d) to assess the usefulness of implementing as routine test the determination of anti-P antibodies., Material and Methods: The study included 60 patients diagnosed of ESL and 61 healthy subjects as the control group. ELISA was used to determine anti-ribosomal antibodies. Chi-square, Fisher and Student t tests were used for the statistical analyses., Results: Of the 60 patients with SLE, 29 (48%) had anti-P antibodies as determined by ELISA. No association was observed between the presence of anti-P antibodies and psychosis, depression, hepatic failure, renal failure or any other clinical signs of ESL. A correlation was found between the levels of anti-P antibodies as determined by ELISA and anti-histone, ANA and AMA antibodies., Conclusions: The prevalence of anti-P antibodies was high among our ESL patients (48%). Their presence was not significantly associated with any clinical sign; however, an association was found with other lab markers related to the presence of active disease.

Aerosol particles in the atmosphere undergo heterogeneous transformations due to interactions with various gas-phase oxidants such as ozone. While it is known that these reactions are significantly affected by the phase state of the particle, a direct comparison between the reaction kinetics and product distributions for the same reactive process occurring in the different phases remains elusive. This study uses single particle levitation and flow-tube methods to measure and compare the ozonolysis of particles containing oleic acid and its trans isomer elaidic acid in liquid, supercooled liquid, and solid states. We measure their evolving size, optical properties, phase, and chemical composition during reaction. Both primary reactions and secondary chemistry were explored, along with the influence of particle phase state on reaction kinetics and product formation. Notably, we directly compare the reaction kinetics of supercooled liquid elaidic acid particles with liquid oleic acid particles, revealing similar uptake coefficients indicative of similar inherent reactivity of the C = C moiety. We go on to compare the kinetics of solid elaidic acid particles, formed due to solidification at room temperature and freezing at low temperature. We found a significant slowing in reaction kinetics that may be attributed to the phase of the particle and the influence of slowed molecular diffusion, supported by qualitative agreement with a multilayer kinetic model (KM-SUB). We further explore differences in the product distributions between particles exhibiting different phase states. These results provide important insights into how the chemical aging of ambient aerosol particles may be influenced by their physicochemical characteristics. [ABSTRACT FROM AUTHOR]

Atmospheric aerosol effects on ecological and human health remain uncertain due to their highly complex and evolving nature when suspended in air. Atmospheric chemistry, global climate/oceanic and health exposure models need to incorporate more realistic representations of aerosol particles, especially their bulk and surface chemistry, to account for the evolution in aerosol physicochemical properties with time. (Photo)chemistry driven by iron (Fe) in atmospheric aerosol particles from natural and anthropogenic sources remains limited in these models, particularly under aerosol liquid water conditions. In this feature article, recent advances from our work on Fe (photo)reactivity in multicomponent aerosol systems are highlighted. More specifically, reactions of soluble Fe with aqueous extracts of biomass burning organic aerosols and proxies of humic like substances leading to brown carbon formation are presented. Some of these reactions produced nitrogen-containing gaseous and condensed phase products. For comparison, results from these bulk aqueous phase chemical studies were compared to those from heterogeneous reactions simulating atmospheric aging of Fe-containing reference materials. These materials include Arizona test dust (AZTD) and combustion fly ash particles. Also, dissolution of Fe and other trace elements is presented from simulated human exposure experiments to highlight the impact of aerosol aging on levels of trace metals. The impacts of these chemical reactions on aerosol optical, hygroscopic and morphological properties are also emphasized in light of their importance to aerosol–radiation and aerosol–cloud interactions, in addition to biogeochemical processes at the sea/ocean surface microlayer upon deposition. Future directions for laboratory studies on Fe-driven multiphase chemistry are proposed to advance knowledge and encourage collaborations for efficient utilization of expertise and resources among climate, ocean and health scientific communities. [ABSTRACT FROM AUTHOR]

This article deals with the reasons and dynamics of the Lebanese immigration to Brazil since the end of the 19th century onward, adding figures and charts to better expose and explain this social economic phenomena. For this, the article relied on a number of fugures, statisctics and studies to explain the reasons for this mass immigration of the Lebanese people. [ABSTRACT FROM AUTHOR]

This paper investigates the ultimate resistance of aluminum circular hollow sections (C.H.S.) under simple load cases as affected by local buckling and material strain hardening. Following the development of advanced non-linear shell finite element models and their validation against existing test data, extensive non-linear numerical analyses were carried out, varying several key parameters such as alloy types, load case (compression or pure bending) and various section dimensions. The numerical results are used as references to analyze the structural performance of aluminum C.H.S., and to assess the accuracy of design equations based on the Overall Interaction Concept (O.I.C.). The O.I.C.-based proposal is shown to yield more accurate, consistent, and continuous resistance predictions than Eurocode 9 recommendations. [ABSTRACT FROM AUTHOR]

Aluminum appears as a promising structural material as it shows many benefits such as a great strength to weight ratio, low maintenance costs, resistance to corrosion, recyclability, etc. Accordingly, characterizing the behavior and resistance of different aluminum sections under various loading conditions is essential. The current paper presents an experimental investigation on aluminum sections with simple and complex geometries to study the effect of cross-section shape on the buckling response of the aluminum sections. Firstly, eight tensile coupon tests were conducted on coupons of aluminum alloy 6061-T6 to accurately determine its material properties. Geometrical imperfections on the surface of each specimen were then measured using a 3D scanner. Further, eight stub column tests were also performed to study the behavior of I, H and complex cross-sections under pure compression. In addition to this, 12 cross-section tests under combined compression and bending are currently under way to study the buckling behavior of these specimens under eccentric compression. [ABSTRACT FROM AUTHOR]

Marine aerosols strongly influence climate through their interactions with solar radiation and clouds. However, significant questions remain regarding the influences of biological activity and seawater chemistry on the flux, chemical composition, and climate-relevant properties of marine aerosols and gases. Wave channels, a traditional tool of physical oceanography, have been adapted for large-scale ocean-atmosphere mesocosm experiments in the laboratory. These experiments enable the study of aerosols under controlled conditions which isolate the marine system from atmospheric anthropogenic and terrestrial influences. Here, we present an overview of the 2019 Sea Spray Chemistry and Particle Evolution (SeaSCAPE) study, which was conducted in an 11 800 L wave channel which was modified to facilitate atmospheric measurements. The SeaSCAPE campaign sought to determine the influence of biological activity in seawater on the production of primary sea spray aerosols, volatile organic compounds (VOCs), and secondary marine aerosols. Notably, the SeaSCAPE experiment also focused on understanding how photooxidative aging processes transform the composition of marine aerosols. In addition to a broad range of aerosol, gas, and seawater measurements, we present key results which highlight the experimental capabilities during the campaign, including the phytoplankton bloom dynamics, VOC production, and the effects of photochemical aging on aerosol production, morphology, and chemical composition. Additionally, we discuss the modifications made to the wave channel to improve aerosol production and reduce background contamination, as well as subsequent characterization experiments. The SeaSCAPE experiment provides unique insight into the connections between marine biology, atmospheric chemistry, and climate-relevant aerosol properties, and demonstrates how an ocean-atmosphere-interaction facility can be used to isolate and study reactions in the marine atmosphere in the laboratory under more controlled conditions. [ABSTRACT FROM AUTHOR]

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The optimisation of the design method for verification of slender steel beam-columns is still a current issue not only from scientific point of view, but also for design practice. Therefore, the main objective of this paper is comparison of the suitability of established design approaches, according to the European standards for steel and aluminium structures, on the basis of numerical simulations. Thus, a finite element model was validated on the basis of experimental analysis available in the scientific literature. To perform the comparison of accuracy of design approaches according to European standards, a commercial software program ANSYS was used for observation of the resistances of beam-columns. The resistance of european I beams with parallel flanges (IPE) and a rectangular hollow cross-section (RHS) were investigated for four load cases on a simply supported member and also on a pinned-fixed beam column with linear bending moment distribution, where the resistance of the cross-section governs. Finally, the conclusions for suitability of the respective design approaches are discussed, together with some findings that arose from this work. [ABSTRACT FROM AUTHOR]

Sulfate aerosol is responsible for a net cooling of the Earth's atmosphere due to its ability to backscatter light. Through atmospheric multiphase chemistry, it reacts with isoprene epoxydiols leading to the formation of aerosol and organic compounds, including organosulfates and high-molecular weight compounds. In this study, we evaluate how sulfate aerosol light backscattering is modified in the presence of such organic compounds. Our laboratory experiments show that reactive uptake of isoprene epoxydiols on sulfate aerosol is responsible for a decrease in light backscattering compared to pure inorganic sulfate particles of up to – 12% at 355 nm wavelength and – 21% at 532 nm wavelength. Moreover, while such chemistry is known to yield a core–shell structure, the observed reduction in the backscattered light intensity is discussed with Mie core–shell light backscattering numerical simulations. We showed that the observed decrease can only be explained by considering effects from the complex optical refractive index. Since isoprene is the most abundant hydrocarbon emitted into the atmosphere, and isoprene epoxydiols are the most important isoprene secondary organic aerosol precursors, our laboratory findings can aid in quantifying the direct radiative forcing of sulfates in the presence of organic compounds, thus more clearly resolving the impact of such aerosol particles on the Earth's climate. [ABSTRACT FROM AUTHOR]

Inadequate knowledge regarding specific local and interactive behavior of slender high‐strength steel (HSS) hollow sections presents an obstacle in implementing these sections in the construction practice. The current approach in the standard is simplified and offers overly conservative results. Dealing with non‐standard cross‐sections only expands on these difficulties. This paper contributes to the on‐going RFCS project "HOLLOSSTAB", which has been dealing with the aforementioned issues. The project design proposal is based on the "Overall interaction concept" (OIC), and a new set of design rules for hollow sections is currently being developed. In this concept, linear buckling analysis (LBA) is used to obtain the slenderness of the member, and Geometrically and Materially Non‐linear Imperfection Analysis (GMNIA) is used to determine an "overall" buckling reduction factor. Extensive experimental tests are used to validate the method, by correlating the experimental results with numerical test results (GMNIA‐real) and statistically analyzing them. The focus of the tests in this paper is the use of high‐strength steel, ranging from S500 to S890, used for rectangular hollow‐sections and hexagonal‐hollow sections. The state‐of‐the‐art measuring tools available, offer the possibility of precise reverse‐engineering process, creating numerical models based on experimental test, which allows an accurate prediction of the ultimate load capacity of the specimens. Digital image correlation (DIC) allows a review of the buckling shape, comparing numerical model with real shape of tested specimen. The paper aims to validate the numerical models, as well as validity of assumptions on imperfection amplitude. [ABSTRACT FROM AUTHOR]

Laterally and torsionally unrestrained steel I-section beams are susceptible to torsional deformations between supports; therefore, according to Part 1-1 of Eurocode 3, they need to be designed to resist lateral-torsional buckling. Eurocode's steelwork design criteria require safety checking based on two stability interaction formulae utilizing the so-called equivalent uniform moment factors and the cross-section resistance formula that, in the case of moment gradient, refer to the beam end section. Uncoupling the beam stability resistance criterion and the cross-section resistance criterion may result in a nonuniform safety assessment of I-section beams. Finite element simulations of the beam resistance for different moment gradient ratios are performed. Verification of the buckling resistance is conducted by varying the following parameters: the slenderness ratio, the location of maximum end moments about both axes and the section depth-to-width ratio (i.e., considering rolled I- and H-sections). The variation in the accuracy of the current Eurocode resistance evaluation method is identified, and an approach for a better equalization of the safety predictions is suggested by considering different values of the most important factors influencing the stability performance of steel I-section beams. [ABSTRACT FROM AUTHOR]

The article discusses the association of anti-ribosomal P (anti-P) antibody in patients with systemic lupus erythematosus (SLE). It examines the relation of anti-P in the clinical and serological disorders in SLE. It notes that the anti-P antibody is significantly associated with malar rash, oral ulcer, photosensitivity and serum anti-dsDNA antibody.

This paper presents a comprehensive computational investigation of the elastic nonlinear buckling response of near-perfect and highly imperfect uniform-thickness thin cylindrical shells of varying length under combined uniform compression and bending. In particular, the elastic ovalization phenomenon in cylindrical shells of sufficient length under combined compression and bending was systematically investigated with finite elements for the first time. The study considered a representative range of practical lengths up to very long cylinders in which ovalization is fully developed under uniform bending and Euler column buckling controls under uniform axial compression. The imperfection sensitivity of the system was studied by introducing a single idealized axisymmetric weld depression imperfection at the midspan of the cylinder. The predictions permit an exploration of the nonlinear mechanics of the generally unfavorable interaction between bending and axial compression at the elastic nonlinear buckling limit state in thin long cylinders. The interaction is at its most unfavorable in cylinders where Euler column buckling is about to become critical, and is qualitatively very different from the favorable moment-force interaction at the reference plastic limit state of circular tubes. A simple closed-form algebraic characterization of the interaction is proposed considering both imperfections and ovalization. [ABSTRACT FROM AUTHOR]