Organic acids as cloud condensation nuclei: Laboratory studies of highly soluble and insoluble species

International audienceThe ability of sub-micron-sized organic acid particles to act as cloud condensation nuclei (CCN) has been examined at room temperature using a newly constructed continuous-flow, thermal-gradient diffusion chamber (TGDC). The organic acids studied were: oxalic, malonic, glutaric, oleic and stearic. The CCN properties of the highly soluble acids - oxalic, malonic and glutaric - match very closely Köhler theory predictions which assume full dissolution of the dry particle and a surface tension of the growing droplet equal to that of water. In particular, for supersaturations between 0.3 and 0.6, agreement between the dry particle diameter which gives 50% activation and that calculated from Köhler theory is to within 3nm on average. In the course of the experiments, considerable instability of glutaric acid particles was observed as a function of time and there is evidence that they fragment to some degree to smaller particles. Stearic acid and oleic acid, which are both highly insoluble in water, did not activate at supersaturations of 0.6% with dry diameters up to 140nm. Finally, to validate the performance of the TGDC, we present results for the activation of ammonium sulfate particles that demonstrate good agreement with Köhler theory if solution non-ideality is considered. Our findings support earlier studies in the literature that showed highly soluble organics to be CCN active but insoluble species to be largely inactive

Automated Sensing System for Monitoring Road Surface Condition Using Fog Computing

The principle point of this task is to build up an Intelligent Monitoring System used to screen the Road Surface Condition using Fog Computing that increases the road safety. Multiple solutions have been proposed which make use of mobile sensing, more specifically contemporary applications and architectures that are used in both crowd sensing and vehicle based sensing. Nonetheless, these initiatives have not been without challenges that range from mobility support, location awareness, low latency as well as geo-distribution. As a result, a new term has been coined for this novel paradigm, called, fog computing

Single- and few-layer graphene growth on stainless steel substrates by direct thermal chemical vapor deposition

Steeping interest on graphene research in basic sciences and applications emphasizes the need for an economical means of synthesizing it. We report a method for the synthesis of graphene on commercially available stainless steel foils using direct thermal chemical vapor deposition. Our method of synthesis and the use of relatively cheap precursors such as ethanol (CH3CH2OH) as a source of carbon and SS 304 as the substrate, proved to be economically viable. Presence of single- and few-layer graphene was confirmed using confocal Raman microscopy/spectroscopy. X-ray photoelectron spectroscopic measurements were further used to establish the influence of various elemental species present in stainless steel on graphene growth. Role of cooling rate on surface migration of certain chemical species (oxides of Fe, Cr and Mn) that promote or hinder the growth of graphene is probed. Such analysis of the chemical species present on the surface can be promising for graphene based catalytic research

Nonlocal symmetries of a class of scalar and coupled nonlinear ordinary differential equations of any order

In this paper we devise a systematic procedure to obtain nonlocal symmetries of a class of scalar nonlinear ordinary differential equations (ODEs) of arbitrary order related to linear ODEs through nonlocal relations. The procedure makes use of the Lie point symmetries of the linear ODEs and the nonlocal connection to deduce the nonlocal symmetries of the corresponding nonlinear ODEs. Using these nonlocal symmetries we obtain reduction transformations and reduced equations to specific examples. We find the reduced equations can be explicitly integrated to deduce the general solutions for these cases. We also extend this procedure to coupled higher order nonlinear ODEs with specific reference to second order nonlinear ODEs.Comment: Accepted for publication in J. Phys. A Math. Theor. 201

Plasma levels of angiopoietin-1 and -2 predict cerebral malaria outcome in Central India

<p>Abstract</p> <p>Background</p> <p>The mechanisms underlying the pathogenesis of cerebral malaria (CM) syndrome are not well understood. Previous studies have shown a strong association of inflammatory chemokines, apoptotic markers and angiogenic molecules with CM associated mortality. Recognizing the importance of angiopoietins (ANG) in the pathogenesis of CM, a retrospective investigation was carried out in a hospital cohort of malaria patients with <it>Plasmodium </it>infection in central India to determine if these factors could be suitable markers of CM associated severity.</p> <p>Methods</p> <p>Patients enrolled in the study were clinically characterized as healthy controls (HC), mild malaria (MM), CM survivors (CMS) and CM non-survivors (CMNS) based on their malaria status and hospital treatment outcome. Plasma ANG-1 and ANG-2 levels were assessed using sandwich ELISA. Receiver operating characteristic (ROC) curve analysis was used to calculate area under the curve (AUC) for each biomarker in order to assess predictive accuracy of individual biomarkers.</p> <p>Results</p> <p>The plasma levels of ANG-1 were lower in CMS and CMNS compared to control groups (mild malaria and healthy controls) at the time of hospital admission. On the contrary, ANG-2 levels positively correlated with malaria severity and were significantly higher in CMNS. The ratio of ANG-2/ANG-1 was highest in CMNS compared to other groups. Receiver operating characteristic curves revealed that compared to ANG-1 (AUC = 0.35), ANG-2 (AUC = 0.95) and ratio of ANG-2/ANG-1 (AUC = 0.90) were better markers to discriminate CMNS from MM cases. However, they were less specific in predicting fatal outcome amongst CM cases at the time of hospital admission.</p> <p>Conclusion</p> <p>These results suggest that at the time of admission plasma levels of ANG-2 and ratio of ANG-2/ANG-1 are clinically informative biomarkers to predict fatal CM from MM cases while they have limited usefulness in discriminating fatal CM outcomes in a pool of CM cases in endemic settings of Central India.</p

Effects of Next-Nearest-Neighbor Hopping on the Hole Motion in an Antiferromagnetic Background

In this paper we study the effect of next-nearest-neighbor hopping on the dynamics of a single hole in an antiferromagnetic (N\'{e}el) background. In the framework of large dimensions the Green function of a hole can be obtained exactly. The exact density of states of a hole is thus calculated in large dimensions and on a Bethe lattice with large coordination number. We suggest a physically motivated generalization to finite dimensions (e.g., 2 and 3). In $d=2$ we present also the momentum dependent spectral function. With varying degree, depending on the underlying lattice involved, the discrete spectrum for holes is replaced by a continuum background and a few resonances at the low energy end. The latter are the remanents of the bound states of the $t-J$ model. Their behavior is still largely governed by the parameters $t$ and $J$. The continuum excitations are more sensitive to the energy scales $t$ and $t_1$.Comment: To appear in Phys. Rev. B, Revtex, 23 pages, 10 figures available on request from [email protected]

Crystal structure of a complex between β-glucopyranose and a macrocyclic receptor with dendritic multicharged water solubilizing chains

International audienceUsing commercial screens for crystallization of biomolecules and taking advantage of the use of racemic crystallography allowed the production of x-ray quality single crystals and the elucidation at 1.08 Å resolution of the solid state structure of a difficult target: the complex between glucopyranose and a water soluble macrocyclic receptor equipped with dendritic multianionic solubilizing chains

Real world evidence of effectiveness and safety of an oral formulation containing un-denatured type-II collagen 40 mg and aflapin 100 mg (HAPID®) in the management of osteoarthritis of knee: findings of a prospective, multi-center, observational study

Background: Osteoarthritis (OA) of knee is a common progressive multifactorial joint disorder affecting the quality of life, and surgical repair is the final option which has substantial impact on healthcare costs. This real-world study evaluates the efficacy and safety of an oral formulation containing UC-II and aflapin (Boswellia serrata extract enriched in 3-O-acetyl-11-keto-beta-boswellic acid) for treatment of OA of knee.Methods: Data of 505 ambulatory adult patients (study duration-Jul-21 to Jul-22) of either gender (227 M, 278 F) having OA of knee, and who received study treatment (capsule HAPID®, Wockhardt, India) once daily for a period of up to 90 days were included for the study after obtaining informed written consent. Primary outcomes were mean change in Western Ontario and McMaster universities OA index (WOMAC) scores from baseline through day 90 (total and sub-scales for joint pain, joint stiffness, and physical function), and change in 0-10 visual analogue scale (VAS) score for pain.Results: About 285 (56.4%) patients were newly diagnosed, majority (63.4%) were having grade 2 severity of OA (Kellgren and Lawrence grade). The mean (SD) baseline total WOMAC scores improved from 60.94 (23.60) at baseline to 26.42 (22.19) on day 90. Significant improvements were seen starting from day 5 (p=0.023) and progressively up to day 90 (p&lt;0.0001).Conclusions: The excellent safety and efficacy profile of combination therapy with aflapin and UC-II makes it a desirable pharmacological treatment modality for management of patients of knee OA

Fluorescent Pigment and Phenol Glucosides from the Heartwood of Pterocarpus marsupium

The fluorescence shown by extracts of the heartwood of Pterocarpus marsupium is attributed to salts of the new compound 1, whose structure was elaborated using detailed spectroscopic/ spectrometric studies. The plant material also contains the nonfluorescent compounds 2 and 3. The absolute configuration of 1 was determined by experimental and theoretically calculated electronic CD spectra, while that of 3 was deduced from ECD comparison with reported results in the α-hydroxydihydrochalcone series

Calculating the energy spectra of magnetic molecules: application of real- and spin-space symmetries

The determination of the energy spectra of small spin systems as for instance given by magnetic molecules is a demanding numerical problem. In this work we review numerical approaches to diagonalize the Heisenberg Hamiltonian that employ symmetries; in particular we focus on the spin-rotational symmetry SU(2) in combination with point-group symmetries. With these methods one is able to block-diagonalize the Hamiltonian and thus to treat spin systems of unprecedented size. In addition it provides a spectroscopic labeling by irreducible representations that is helpful when interpreting transitions induced by Electron Paramagnetic Resonance (EPR), Nuclear Magnetic Resonance (NMR) or Inelastic Neutron Scattering (INS). It is our aim to provide the reader with detailed knowledge on how to set up such a diagonalization scheme.Comment: 29 pages, many figure