Chirality and the origin of atmospheric humic-like substances

Aerosol water extracts and atmospheric humic-like substances (HULIS) obtained from PM2.5-fraction aerosol samples collected in a rural/continental background environment and in an urban environment in spring and summer, and at a tropical site that was heavily impacted by biomass burning were studied. HULIS was obtained as the water-soluble, methanol-elutable material isolated from a solid-phase extraction procedure. The mean organic matter-to-organic carbon mass conversion factor and the standard deviation of 2.04 +/- 0.06 were derived for HULIS from biomass burning. Mean atmospheric concentrations of HULIS for the rural and urban environments and for the biomass burning during daylight periods and nights, were 1.65, 2.2, 43, and 60 mu gm(-3), respectively. This and other abundances indicate that intense emission sources and/or formation mechanisms of HULIS operate in biomass burning. Mean contributions of C in HULIS (HULIS-C) to water-soluble organic carbon (WSOC) were 35, 48, 63, and 76%, respectively, for the sample set listed. HULIS-C is the major component of the WSOC in tropical biomass burning. The data also suggest that HULIS most likely do not share common origin in the three environments studied. Differentiation among the possible formation processes was attempted by investigating the optical activity of HULIS through their (electronic and vibrational) circular dichroism properties. The urban HULIS did not show optical activity, which is in line with the concept of their major airborne formation from anthropogenic aromatics. The rural HULIS revealed weak optical activity, which may be associated with one of their important formation pathways by photo-oxidation and oligomerisation, i.e., with the formation from chiral biogenic precursors with one of the enantiomers slightly enriched. The The biomass burning of HULIS exhibited a strong effect in the vibrational circular dichroism as a clear distinction from the other two types. This was related to the contribution of the thermal degradation products of lignins and cellulose. The biomass burning of HULIS resemble Suwannee River Fulvic Acid standard more closely in some aspects than the urban and rural types of HULIS, which may be related to their common origin from plant material

Cysteine proteases: The S2P2 hydrogen bond is more important for catalysis than is the analogous S1P1 bond

AbstractHigh hydrophobicity of the second amino acid N-terminal to the scissile bond (P2 residue) is generally considered to be the major factor in the specificity of the substrates for cysteine proteases of the papain family. To examine the catalytic contribution of the S2P2 hydrogen bond apparent from X-ray crystallographic studies, the kinetics of Z-Phe-Gly-OEt and its thiono derivative were compared. The thiono compound contains a sulfur atom in place of the carbonyl oxygen of the phenylalanine residue. It was found that the specificity rate constants for the reactions of the thiono substrate with various cysteine proteases are lower by 2–3 orders of magnitude as compared to the corresponding rate constants for the oxo substrate. This remarkable effect is not expected in the light of previous studies indicating that the change from oxygen to sulfur in the P1 residue was without an appreciable effect. The results are interpreted in terms of a distorted binding of the thiono substrate

Numerical Analysis of Sub-critical Crack Growth in Particulate Ceramic Composites

AbstractThe strength of glass or ceramic containing materials can be affected by the environment (“stress corrosion”). Under applied stress, crack-like defects may grow (sub-critically) for stress intensity factors, KI, below the fracture toughness of the material, KIc. The aim of the present work was to develop a two-dimensional finite element model to analyze the subcritical crack growth behavior of ceramic-based particulate composites. The maximum tangential stress criterion (MTS) was used to predict the direction of the crack propagation, in the framework of linear elastic fracture mechanics. The modeled material was a Low Temperature Co-fired Ceramic (LTCC), containing alumina particles embedded in a glass matrix. The experimentally determined SCCG material behavior (i.e. v-KI data) was implemented in the numerical model. The effect of the elastic modulus of the particles on the subcritical crack propagation was investigated. The conclusions of this paper can contribute to a better understanding of the subcritical propagation of cracks in particulate composites

Fracture toughness of multilayer pipes

Multilayer pipes composed of various materials improve partially the properties of a pipe system and are frequently used in service. To estimate the lifetime of these pipes the basic fracture parameters have to be measured. In the contribution a new approach to this estimation is presented. Special type of a C-shaped inhomogeneousfracture mechanics specimen machined directlyfrom a pipe has been proposed, numerically analyzed and tested. The corresponding K values are calculated by FEM and fracture toughness values of HDPE pipes material are obtained.Многослойные трубы, состоящие из различ­ных материалов, позволяют частично повы­сить свойства систем трубопроводов и часто применяются на практике. Для оценки долго­ вечности таких труб необходимо определить их основные параметры разрушения. Пред­ставлен новый подход к выполнению такой оценки. Предлагается специальный тип не­ однородного С-образного образца, вырезаемо­го непосредственно из трубы, для исследова­ния методами механики разрушения; выполнен численный анализ и проведены испытания. Расчет соответствующих значений К выполнен методом конечных элементов. Полу­чены величины трещиностойкости материа­ла труб из полиэтилена высокой плотности

Review of the thermoluminescent dosimetry method for the environmental dose monitoring

Passive solid state dosimeters, such as thermoluminescence dosimeters, provide integrated measurement of the total dose and are widely used in environmental monitoring programs. The objective of this paper is to provide a comprehensive review on the use of thermoluminescent dosimetry methods for monitoring radiation dose in the environment. The article presents the part of the research results of the project PREPAREDNESS (EMPIR 2016 call for Metrology for Environment joint research project) with a particular objective to harmonize procedures used by dosimetry services, relevant authorities and Institutes across the Europe. To achieve this, different monitoring routines that are based on passive environ mental dosimetry methods are investigated. Differences in performing specific steps such as preheating, reading, annealing, minimizing fading, and others, are analyzed. The investigation was performed by means of qualitative literature review that showed the lack of information about specific steps. The conclusion of this work is that thermoluminescent dosimetry measurement system has to be type-tested even though the testing procedure is complicated. In addition to this, control dosimeters should be introduced, International Organization for Standardization protocols should be followed during calibration, and finally, parameters influencing the measurement uncertainty have to be identified and well understood in order to pro duce ac cu rate dose measurement results

Fast geometric gate operation of superconducting charge qubits in circuit QED

A scheme for coupling superconducting charge qubits via a one-dimensional superconducting transmission line resonator is proposed. The qubits are working at their optimal points, where they are immune to the charge noise and possess long decoherence time. Analysis on the dynamical time evolution of the interaction is presented, which is shown to be insensitive to the initial state of the resonator field. This scheme enables fast gate operation and is readily scalable to multiqubit scenario

Carfilzomib and dexamethasone versus eight cycles of bortezomib and dexamethasone in patients with relapsed or refractory multiple myeloma : an indirect comparison using data from the phase 3 ENDEAVOR and CASTOR trials

Altres ajuts: This analysis and the development of this manuscript were funded by Amgen (Europe) GmbH. Medical writing support, funded by Amgen (Europe) GmbH, was provided by Oxford PharmaGenesis, Oxford, UK. Editorial support was provided by Carine Thual of Amgen (Europe) GmbH.In ENDEAVOR, carfilzomib and dexamethasone (Kd56) demonstrated significant improvement in progression-free survival (PFS) compared with bortezomib and dexamethasone (Vd). Both agents were administered until disease progression; the EU label for Vd, however, stipulates a maximum of eight treatment cycles. Here, matching-adjusted treatment comparison was used to compare efficacy of Kd56 with Vd, if Vd was administered for 8 cycles (Vd-8). Data from ENDEAVOR and CASTOR trials (which compared daratumumab, bortezomib, and dexamethasone with Vd-8) were used. Hazard ratios of PFS were estimated for Vd vs. Vd-8 and Kd vs. Vd-8. For cycles 1-8, risk reduction in PFS for Kd56 vs. Vd-8 was equal to that estimated in ENDEAVOR (HR: 0.53; 95% CI 0.44-0.65). Beyond eight cycles, risk reduction in PFS for Kd56 and Vd-8 was estimated to be 60% (HR: 0.40; 95% CI 0.26-0.63). The analysis suggested that PFS benefit of Kd56 over Vd increases when Vd is given for eight cycles only

Harmonisation of dose measurement procedures using passive dosemeters: use of passive H*(10) dosimetry systems in Europe

Jedan od zadataka projekta 16ENV04 Preparedness jeispitivanje pasivnih dozimetrijskih sistema namenjenih za merenje operativne dozimetrijske veličine H*(10). Cilj ovog zadatka je evaluacija i harmonizacija procedura koji koriste laboratorije u Evropi a odnose se na merenje ambijentlnog ekvivalenta doze,a u vezi eventualne primene ovakvih doziemtrisjkih sistema u kontekstu dleovanja u vanrednom događaju.One of the outstanding tasks of the project 16ENV04 Preparedness, is to investigate the use of passive dosemeters aimed for measurement of operational quantityH*(10). The aim of this task is to develop a rationale to harmonize the procedures used by European measuring bodies and authorities, which provide services or fulfil tasks in radiation protection by using passive H*(10) area monitoring systems. Procedures used by European measuring bodies and services for environmental monitoring using passive area dosemeters are investigated, with a goal to investigate the applicability of passive dosimetry systems in the aftermath of a nuclear event.Proceedings: [http://vinar.vin.bg.ac.rs/handle/123456789/8681]XXX симпозијум ДЗЗСЦГ (Друштва за заштиту од зрачења Србије и Црне Горе), 2- 4. октобар 2019. године, Дивчибаре, Србиј

Entanglement Sudden Death in Band Gaps

Using the pseudomode method, we evaluate exactly time-dependent entanglement for two independent qubits, each coupled to a non-Markovian structured environment. Our results suggest a possible way to control entanglement sudden death by modifying the qubit-pseudomode detuning and the spectrum of the reservoirs. Particularly, in environments structured by a model of a density-of-states gap which has two poles, entanglement trapping and prevention of entanglement sudden death occur in the weak-coupling regime