Effect of the biobased polyols chemical structure on high performance thermoset polyurethane properties

The sustainability of the polymeric materials has become a fundamental challenge; therefore, the development of new biobased formulations has gained increasing interest. Thermoset polyurethanes (PURs) present high performance and are a competitive solution for structural composites. However, polyols used in the PUR synthesis are typically from petrochemical origin. Nowdays, a broad range of biobased polyols is available in the market, but there is not yet a specific formulation for high performance PURs composites. The aim of this work was to study the effect of biobased polyols' characteristics in the PUR processing and final properties. In addition, biobased polyol features to synthesize BIO-PURs suitable for structural applications were stablished. The viscosity and reactivity were studied by means of rheology and differential scanning calorimetry (DSC). Thermal and mechanical properties were studied through thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA) and flexural tests. The results obtained demonstrated the dramatic influence of polyols’ nature on BIO-PUR/PUR properties and their effect on the crosslink density. It was observed that using a high functionality and high hydroxyl index biobased polyol, it was possible to synthesize high performance BIO-PUR suitable for structural composites.We gratefully acknowledge the Basque Government for the financial support through the ELKARTEK 2021 (Project NEOMAT KK-2021/00059) program and in the frame of Grupos Consolidados (IT-1690-22). The authors also acknowledge the University of the Basque Country (UPV/EHU) in the frame of GIU18/216 Research Group and the Macrobehavior-Mesostructure-Nanotechnology SGIker unit

Effects of family control on the degree and type of diversification: empirical evidence for business groups

This article analyzes the impact of ownership structure on corporate diversification,with reference to large listed family business groups. By considering agency theoryand socioemotional wealth, the study examines the relationship between family own-ership, concentration of ownership, and degree and type of diversification. The studyconsiders 99 Spanish listed business groups (50 family-controlled- and 49 nonfamily-controlled groups) and considers diversification of business group as the focus ofanalysis. The results show how family business groups present a lower preference forunrelated diversification than related diversification. There is also a nonlinear rela-tionship between the concentration of ownership in family groups and the degree ofdiversification, showing different behaviors in family groups according to sharesowned by the family's leading shareholders. This article contributes to the literatureby providing a more precise identification of the corporate strategy adopted by busi-ness groups and establishing new evidence about the impact of family control ondiversification strategies and the differences regarding nonfamily business groups

Occupational exposure to nano-TiO2 in the life cycle steps of new depollutant mortars used in construction

The present work is focused on the measurement of workers exposure to nano-TiO2 in the life cycle steps of depollutant mortars. It has been done in the framework of the SCAFFOLD project, which aims at the management of potential risks arising from the use of manufactured nanomaterials in construction. Main findings can be summarized as follows: (1) The occupational exposure to nano- TiO2 is below 0.3 mg/m3 for all measured scenarios. The highest concentrations were measured during the cleaning task (in the nano- TiO2 manufacturing process) and during the application (spraying) of depollutant coatings on a wall. (2) It was found a high release of particles above the background in several tasks as expected due to the nature of the activities performed. The maximum concentration was measured during drilling and during adding powder materials (mean total particle concentration up to 5.591E+04 particles/cm3 and 5.69E+04 particles/cm3). However, considering data on total particle concentration released, no striking differences have been observed when tasks have been performed using conventional materials in the sector (control) and when using materials doped with nano-objects.European Commission's FP

Strategies, methods and tools for managing nanorisks in construction

This paper presents a general overview of the work carried out by European project SCAFFOLD (GA 280535) during its 30 months of life, with special emphasis on risk management component. The research conducted by SCAFFOLD is focused on the European construction sector and considers 5 types of nanomaterials (TiO2, SiO2, carbon nanofibres, cellulose nanofibers and nanoclays), 6 construction applications (Depollutant mortars, selfcompacting concretes, coatings, self-cleaning coatings, fire resistant panels and insulation materials) and 26 exposure scenarios, including lab, pilot and industrial scales. The document focuses on the structure, content and operation modes of the Risk Management Toolkit developed by the project to facilitate the implementation of "nano-management" in construction companies. The tool deploys and integrated approach OHSAS 18001 - ISO 31000 and is currently being validated on 5 industrial case studies.Research carried out by project SCAFFOLD was made possible thanks to funding from the European Commission, through the Seventh Framework Programme (GA 280535

Quantification of the 2-Deoxyribonolactone and Nucleoside 5 '-Aldehyde Products of 2-Deoxyribose Oxidation in DNA and Cells by Isotope-Dilution Gas Chromatography Mass Spectrometry: Differential Effects of gamma-Radiation and Fe2+-EDTA

The oxidation of 2-deoxyribose in DNA has emerged as a critical determinant of the cellular toxicity of oxidative damage to DNA, with oxidation of each carbon producing a unique spectrum of electrophilic products. We have developed and validated an isotope-dilution gas chromatography-coupled mass spectrometry (GC−MS) method for the rigorous quantification of two major 2-deoxyribose oxidation products: the 2-deoxyribonolactone abasic site of 1′-oxidation and the nucleoside 5′-aldehyde of 5′-oxidation chemistry. The method entails elimination of these products as 5-methylene-2(5H)-furanone (5MF) and furfural, respectively, followed by derivatization with pentafluorophenylhydrazine (PFPH), addition of isotopically labeled PFPH derivatives as internal standards, extraction of the derivatives, and quantification by GC−MS analysis. The precision and accuracy of the method were validated with oligodeoxynucleotides containing the 2-deoxyribonolactone and nucleoside 5′-aldehyde lesions. Further, the well-defined 2-deoxyribose oxidation chemistry of the enediyne antibiotics, neocarzinostatin and calicheamicin γ1I, was exploited in control studies, with neocarzinostatin producing 10 2-deoxyribonolactone and 300 nucleoside 5′-aldehyde per 106 nt per μM in accord with its established minor 1′- and major 5′-oxidation chemistry. Calicheamicin unexpectedly caused 1′-oxidation at a low level of 10 2-deoxyribonolactone per 106 nt per μM in addition to the expected predominance of 5′-oxidation at 560 nucleoside 5′-aldehyde per 106 nt per μM. The two hydroxyl radical-mediated DNA oxidants, γ-radiation and Fe2+−EDTA, produced nucleoside 5′-aldehyde at a frequency of 57 per 106 nt per Gy (G-value 74 nmol/J) and 3.5 per 106 nt per μM, respectively, which amounted to 40% and 35%, respectively, of total 2-deoxyribose oxidation as measured by a plasmid nicking assay. However, γ-radiation and Fe2+−EDTA produced different proportions of 2-deoxyribonolactone at 7% and 24% of total 2-deoxyribose oxidation, respectively, with frequencies of 10 lesions per 106 nt per Gy (G-value, 13 nmol/J) and 2.4 lesions per 106 nt per μM. Studies in TK6 human lymphoblastoid cells, in which the analytical data were corrected for losses sustained during DNA isolation, revealed background levels of 2-deoxyribonolactone and nucleoside 5′-aldehyde of 9.7 and 73 lesions per 106 nt, respectively. γ-Irradiation of the cells caused increases of 0.045 and 0.22 lesions per 106 nt per Gy, respectively, which represents a 250-fold quenching effect of the cellular environment similar to that observed in previous studies. The proportions of the various 2-deoxyribose oxidation products generated by γ-radiation are similar for purified DNA and cells. These results are consistent with solvent exposure as a major determinant of hydroxyl radical reactivity with 2-deoxyribose in DNA, but the large differences between γ-radiation and Fe2+−EDTA suggest that factors other than hydroxyl radical reactivity govern DNA oxidation chemistry.National Institute of Environmental Health Sciences (ES002109)National Center for Research Resources (U.S.) (RR023783-01)National Center for Research Resources (U.S.) (RR017905-01)National Cancer Institute (U.S.) (CA103146

Prospective individual patient data meta-analysis of two randomized trials on convalescent plasma for COVID-19 outpatients

Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when = 50 years and symptomatic for <= 7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with <= 5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution

Acoustic Einstein-Hopf Drag on a Bubble

Theoretical results show that the drag on a bubble can be modified by the presence of isotropic, homogeneous, broadband acoustic noise, when the band overlaps the bubbleâ s resonance width. While these results constitute an acoustic analog to the Einstein-Hopf drag on an oscillating dipole in the presence of electromagnetic fluctuations, an important difference is that band-limited acoustic noise can reduce the drag when the lower frequency of the spectrum coincides with the resonant frequency of the bubble. Applications to bubble migration, heat transfer, and acoustophoresis are suggested.This work was sponsored in part by the Naval Postgraduate School Research Program and by the Office of Naval Research

Dispersion relations for gravity waves in a deep fluid: second sound in a stormy sea

We consider the nonlinear processes of interaction between a random field of short deep gravity waves and a deep long gravity wave, as well as the effects of nonlinear interactions among the driven short waves. The interactions are characterized by two types of invariants. First, the short waves posses an adiabatic invariant as regards the interaction with the long waves. Second, a collision between short waves conserved frequency and wave vector. As a consequence of these invariants, extra degrees of freedom appear. This results in a two-fluid description at the surface of the liquid for the mean flow of the long wave plus a distribution of waves. The two-fluid theory implies a spectrum of oscillations of the surface where, besides the usual gravity waves, there exists a surface mode with longitudinal oscillation. The regimes of validity of this hydrodynamic description are discussed, and the solutions for the dispersion relation are also presented. The power spectrum of a stormy sea is derived within the framework on nonlinear wave interactions. Finally, we comment on the relevance of the results to phase-velocity measurement is a wind-wave laboratory experiment, as well as possible experiments to observe the theoretically predicted new mode.Department of Energy, Office of Basic Energy Sciences, Divisio of Engineering and Geoscience, National Research Council and the Naval Postgraduate School Direct Funded Research ProgramApproved for public release; distribution is unlimited

On the Impacts and Benefits of Implementing Full-duplex Communications Links in an Underwater Acoustic Network

Proc of 5th International Mine Symposium, Naval Postgraduate School, Monterey, March 2002.Acoustic signals offer a means of establishing wireless networks in shallow water regions. These networks may provide command and control for autonomous underwater vehicles, forward reporting by arrays of sensor grids, ad hoc communications links to covert forces, or positive control of unmanned, forward-deployed weapons systems. However, the capacity limitations and extreme propagation delays of acoustic communications must be addressed to ensure timely, predictable message delivery. This paper presents the status of current experimentation at the Naval Postgraduate School regarding the viability of full-duplex underwater acoustic communications. As implementation of full-duplex links requires partitioning the total capacity into distinct sub-channels, the paper presents a top-level description and specification of a capacity allocation protocol to mitigate the adverse impacts of such a partitioning when system load is light