Functional characterization of the water-soluble organic carbon of size-fractionated aerosol in the southern Mississippi Valley

The chemical content of water-soluble organic carbon (WSOC) as a function of particle size was characterized in Little Rock, Arkansas in winter and spring 2013. The objectives of this study were to (i) compare the functional characteristics of coarse, fine and ultrafine WSOC and (ii) reconcile the sources of WSOC for periods when carbonaceous aerosol was the most abundant particulate component. The WSOC accounted for 5% of particle mass for particles with <i>d</i>_p > 0.96 μm and 10% of particle mass for particles with <i>d</i>_p < 0.96 μm. Non-exchangeable aliphatic (H–C), unsaturated aliphatic (H–C–C=), oxygenated saturated aliphatic (H–C–O), acetalic (O–CH–O) and aromatic (Ar–H) protons were determined by proton nuclear magnetic resonance (¹H-NMR). The total non-exchangeable organic hydrogen concentrations varied from 4.1 ± 0.1 nmol m⁻³ for particles with 1.5 < <i>d</i>_p < 3.0 μm to 73.9 ± 12.3 nmol m⁻³ for particles with <i>d</i>_p < 0.49 μm. The molar H / C ratios varied from 0.48 ± 0.05 to 0.92 ± 0.09, which were comparable to those observed for combustion-related organic aerosol. The R–H was the most abundant group, representing about 45% of measured total non-exchangeable organic hydrogen concentrations, followed by H–C–O (27%) and H–C–C= (26%). Levoglucosan, amines, ammonium and methanesulfonate were identified in NMR fingerprints of fine particles. Sucrose, fructose, glucose, formate and acetate were associated with coarse particles. These qualitative differences of ¹H-NMR profiles for different particle sizes indicated the possible contribution of biological aerosols and a mixture of aliphatic and oxygenated compounds from biomass burning and traffic exhausts. The concurrent presence of ammonium and amines also suggested the presence of ammonium/aminium nitrate and sulfate secondary aerosol. The size-dependent origin of WSOC was further corroborated by the increasing δ¹³C abundance from −26.81 ± 0.18&permil; for the smallest particles to −25.93 ± 0.31&permil; for the largest particles and the relative distribution of the functional groups as compared to those previously observed for marine, biomass burning and secondary organic aerosol. The latter also allowed for the differentiation of urban combustion-related aerosol and biological particles. The five types of organic hydrogen accounted for the majority of WSOC for particles with <i>d</i>_p > 3.0 μm and <i>d</i>_p < 0.96 μm

Effects of glycerol and creatine hyperhydration on doping-relevant blood parameters

Glycerol is prohibited as an ergogenic aid by the World Anti-Doping Agency (WADA) due to the potential for its plasma expansion properties to have masking effects. However, the scientific basis of the inclusion of Gly as a “masking agent” remains inconclusive. The purpose of this study was to determine the effects of a hyperhydrating supplement containing Gly on doping-relevant blood parameters. Nine trained males ingested a hyperhydrating mixture twice per day for 7 days containing 1.0 g•kg&lt;sup&gt;−1&lt;/sup&gt; body mass (BM) of Gly, 10.0 g of creatine and 75.0 g of glucose. Blood samples were collected and total hemoglobin (Hb) mass determined using the optimized carbon monoxide (CO) rebreathing method pre- and post-supplementation. BM and total body water (TBW) increased significantly following supplementation by 1.1 ± 1.2 and 1.0 ± 1.2 L (BM, P &lt; 0.01; TBW, P &lt; 0.01), respectively. This hyperhydration did not significantly alter plasma volume or any of the doping-relevant blood parameters (e.g., hematocrit, Hb, reticulocytes and total Hb-mass) even when Gly was clearly detectable in urine samples. In conclusion, this study shows that supplementation with hyperhydrating solution containing Gly for 7 days does not significantly alter doping-relevant blood parameters

Public perceptions and expectations: disentangling the hope and hype of organoid research

Organoid technologies are rapidly advancing and hold great potential and hope for disease modeling and clinical translational research. Still, they raise a number of complex, ethical questions regarding their current and future use. Patient and public involvement is impor-tant in building public trust and helping to secure responsible conduct and valued innovations; nevertheless, research into patient and public perspectives on organoid technologies remains scarce. We report on a first public dialogue on organoid technologies through three cross-country deliberative workshops with a diverse group of stakeholders to identify their perceptions and concerns. Participants gener-ally support organoid technologies on the condition that responsible governance, ethical oversight, and sound informed consent procedures are in place. Yet, a broad set of potential concerns are identified, primarily concerning commercialization, healthcare access, and cerebral organoids. Participants' insights and recommendations can help inform researchers and ethics and policy bodies toward supporting responsible and ethical organoid approaches

Strengthening research integrity: which topic areas should organisations focus on?

The widespread problems with scientific fraud, questionable research practices, and the reliability of scientific results have led to an increased focus on research integrity (RI). International organisations and networks have been established, declarations have been issued, and codes of conducts have been formed. The abstract principles of these documents are now also being translated into concrete topic areas that Research Performing organisations (RPOs) and Research Funding organisations (RFOs) should focus on. However, so far, we know very little about disciplinary differences in the need for RI support from RPOs and RFOs. The paper attempts to fill this knowledge gap. It reports on a comprehensive focus group study with 30 focus group interviews carried out in eight different countries across Europe focusing on the following research question: “Which RI topics would researchers and stakeholders from the four main areas of research (humanities, social science, natural science incl. technical science, and medical science incl. biomedicine) prioritise for RPOs and RFOs?” The paper reports on the results of these focus group interviews and gives an overview of the priorities of the four main areas of research. The paper ends with six policy recommendations and a reflection on how the results of the study can be used in RPOs and RFOs.Modern and Contemporary Studie

Emission fluxes and atmospheric degradation of monoterpenes above a boreal forest: field measurements and modelling

The contribution of monoterpenes to aerosol formation processes within and above forests is not well understood. This is also true for the particle formation events observed during the BIOFOR campaigns in Hyytiälä, Finland. Therefore, the diurnal variation of the concentrations of several biogenic volatile organic compounds (BVOCs) and selected oxidation products in the gas and particle phase were measured on selected days during the campaigns in Hyytiälä, Finland. α-pinene and Δ3-carene were found to represent the most important monoterpenes above the boreal forest. A clear vertical gradient of their concentrations was observed together with a change of the relative monoterpene composition with height. Based on concentration profile measurements of monoterpenes, their fluxes above the forest canopy were calculated using the gradient approach. Most of the time, the BVOC fluxes show a clear diurnal variation with a maximum around noon. The highest fluxes were observed for α-pinene with values up to 20 ng m−2 s−1 in summer time and almost 100 ng m−2 s−1 during the spring campaign. Furthermore, the main oxidation products from α-pinene, pinonaldehyde, and from β-pinene, nopinone, were detected in the atmosphere above the forest. In addition to these more volatile oxidation products, pinic and pinonic acid were identified in the particle phase in a concentration range between 1 and 4 ng m−3. Beside these direct measurement of known oxidation products, the chemical sink term in the flux calculations was used to estimate the amount of product formation of the major terpenes (α-pinene, β-pinene, Δ3-carene). A production rate of very low volatile oxidation products (e.g., multifunctional carboxylic) from ·OH- and O3-reaction of monoterpenes of about 1.3·104 molecules cm−3 s−1 was estimated for daylight conditions during summer time. Additionally, model calculations with the one-dimensional multilayer model CACHE were carried out to investigate the diurnal course of BVOC fluxes and chemical degradation of terpenes

Mechanical Deformation Behavior of Nonpolar GaN Thick Films by Berkovich Nanoindentation

In this study, the deformation mechanisms of nonpolar GaN thick films grown on m-sapphire by hydride vapor phase epitaxy (HVPE) are investigated using nanoindentation with a Berkovich indenter, cathodoluminescence (CL), and Raman microscopy. Results show that nonpolar GaN is more susceptible to plastic deformation and has lower hardness thanc-plane GaN. After indentation, lateral cracks emerge on the nonpolar GaN surface and preferentially propagate parallel to the orientation due to anisotropic defect-related stresses. Moreover, the quenching of CL luminescence can be observed to extend exclusively out from the center of the indentations along the orientation, a trend which is consistent with the evolution of cracks. The recrystallization process happens in the indented regions for the load of 500 mN. Raman area mapping indicates that the distribution of strain field coincides well with the profile of defect-expanded dark regions, while the enhanced compressive stress mainly concentrates in the facets of the indentation