Positive and Negative Contributions in the Solvation Enthalpy due to Specific Interactions in Binary Mixtures of C1-C4 n -Alkanols and Chloroform with Butan-2-one

© 2015 American Chemical Society. In the paper, results of calorimetric measurements, IR spectra, and calculated ab initio stabilization energies of dimers are reported for binary systems butan-2-one + (methanol, ethanol, propan-1-ol, butan-1-ol, and chloroform). Changes in the total enthalpy of specific interactions due to dissolution of butan-2-one in the alcohols, calculated using equations derived in previous works, are positive. That results from the endothermic breaking of the O-H···O-H bonds not completely compensated by the exothermic effects of formation of the O-H···O - C ones. Moreover, the concentration of nonbonded molecules of butan-2-one is significant even in dilute solutions, as is evidenced by the shape of the C - O stretching vibrations band in the IR spectra. Apart from that, the spectra do not confirm 1:2 complexes in spite of two lone electron pairs in the carbonyl group of butan-2-one capable of forming the hydrogen bonds. The changes in enthalpy of specific interactions are negative for dilute solutions of alcohols and chloroform in butan-2-one and of butan-2-one in chloroform, because no hydrogen bonds occur in pure butan-2-one. The experimental results are positively correlated with the enthalpies estimated from the ab initio energies using a simple chemical reaction approach

Inhalations of 5-ALA in photodynamic diagnosis of bronchial cancer

Background: Photodynamic bronchoscopy (PDD) allows for early detection of bronchial cancer. Adverse effects and high costs, partly related to general application of photosensitisers, are important limitations of the method. The local application of a photosensitiser could help to minimize these problems. In this study the validity and safety of inhaled 5-ALA have been tested. Methods: We examined 49 patients (age 59±11, cigarette consumption 36±17 pack-years) with present or past respiratory neoplasms and other with increased risk of bronchial cancer by photodynamic bronchoscopy (Storz- D-light) after inhaled 5-ALA. Biopsies were taken from the fluorescence-positive and negative foci (control). Symptoms and pre-/post-inhalation spirometry were analysed. Results: The overall sensitivity was 82%, specificity 62%, positive predicted value (PPV) 45% and negative predictive value (NPV) 90%. Specificity decreased to 53% and PPV to 15% when visible tumours were excluded. PDD, when added to white light bronchoscopy increased sensitivity by 2.1% and NPV by 6%, but decreased specificity by 35.4% and PPV by 53.1%. In a group of actual or past tumours the sensitivity increased by 22% and NPV by 34%, whereas specificity decreased by 26% and PPV by 35%. In 2 cases a drop in FEV1 above 10% of pre-inhalation value was observed but no clinically relevant symptoms were reported. Conclusions: Photodynamic bronchoscopy with inhalation of 5-ALA is a relatively safe diagnostic method. The main disadvantage is high percentage of false positive results. Nevertheless, we believe, that it may be a useful adjunct to conventional diagnostic modes, especially in the detection of early lesions in patients operated due to cancer (stump control and detection of metachronous lesions) and those prepared for operation (synchronous lesions and detection of infiltration margins). However all suspected lesions must be verified by histo-pathological examination

Advances in three-dimensional rapid prototyping of microfluidic devices for biological applications

The capability of 3D printing technologies for direct production of complex 3D structures in a single step has recently attracted an ever increasing interest within the field of microfluidics. Recently, ultrafast lasers have also allowed developing new methods for production of internal microfluidic channels within the bulk of glass and polymer materials by direct internal 3D laser writing. This review critically summarizes the latest advances in the production of microfluidic 3D structures by using 3D printing technologies and direct internal 3D laser writing fabrication methods. Current applications of these rapid prototyped microfluidic platforms in biology will be also discussed. These include imaging of cells and living organisms, electrochemical detection of viruses and neurotransmitters, and studies in drug transport and induced-release of adenosine triphosphate from erythrocytes

Hydrogen-bonded aggregates in the mixtures of piperidine with water: Thermodynamic, SANS and theoretical studies

© 2014 Elsevier B.V. All rights reserved. Structures resembling semiclathrates probably arise in liquid aqueous solutions of piperidine at the amine mole fraction below 0.03. With the increasing concentration, the structures gradually decay, but the 1:1 complexes of piperidine with water remain linked one to another through the OH⋯O bonds between the hydration water molecules. A periodic order of the bicontinuous microemulsion type occurs in the range of the mole fractions from 0.08 to 0.5. In the piperidine-rich mixtures, the 1:1 complexes are dispersed uniformly in the amine. Relatively low stabilization energy of these complexes probably causes that piperidine is totally miscible with water

Effects of treadmill training on microvascular remodeling in the rat following spinal cord injury

Introduction: The morphological characteristics of skeletal muscles innervated caudal to a spinal cord injury (SCI) undergo dramatic phenotypic and microvascular changes. Method: Female Sprague Dawley rats received a severe contusion at thoracic level 9/10, and were randomly assigned to locomotor training (TR), epidural stimulation (ES) or a combination of the treatment groups (CB). Fibre type composition and capillary distribution were assessed in phenotypically distinct compartments of the tibialis anterior. Results: SCI induced a shift in Type II fibre phenotype from oxidative to glycolytic (P<0.05) as well as capillary loss within the oxidative core and glycolytic cortex; the CB treatment best maintained capillary supply within both compartments. Discussion: The angiogenic response of CB training improved capillary distribution across the muscle, becoming spatially more homogeneous and decreasing mean capillary supply area, potentially improving oxygenation. There is an important role for weight bearing training in maintaining the oxidative phenotype of muscle following SCI

The need for sustainability, equity, and international exchange: perspectives of early career environmental psychologists on the future of conferences

At the 2019 and 2021 International Conference on Environmental Psychology, discussions were held on the future of conferences in light of the enormous greenhouse gas emissions and inequities associated with conference travel. In this manuscript, we provide an early career researcher (ECR) perspective on this discussion. We argue that travel-intensive conference practices damage both the environment and our credibility as a discipline, conflict with the intrinsic values and motivations of our discipline, and are inequitable. As such, they must change. This change can be achieved by moving toward virtual and hybrid conferences, which can reduce researchers’ carbon footprints and promote equity, if employed carefully and with informal exchange as a priority. By acting collectively and with the support of institutional change, we can adapt conference travel norms in our field. To investigate whether our arguments correspond to views in the wider community of ECRs within environmental psychology, we conducted a community case study. By leveraging our professional networks and directly contacting researchers in countries underrepresented in those networks, we recruited 117 ECRs in 32 countries for an online survey in February 2022. The surveyed ECRs supported a change in conference travel practices, including flying less, and perceived the number of researchers wanting to reduce their travel emissions to be growing. Thirteen percent of respondents had even considered leaving academia due to travel requirements. Concerning alternative conference formats, a mixed picture emerged. Overall, participants had slightly negative evaluations of virtual conferences, but expected them to improve within the next 5 years. However, ECRs with health issues, facing visa challenges, on low funding, living in remote areas, with caretaking obligations or facing travel restrictions due to COVID-19 expected a switch toward virtual or hybrid conferences to positively affect their groups. Participants were divided about their ability to build professional relationships in virtual settings, but believed that maintaining relationships virtually is possible. We conclude by arguing that the concerns of ECRs in environmental psychology about current and alternative conference practices must be taken seriously. We call on our community to work on collective solutions and less travel-intensive conference designs using participatory methods. Copyright © 2022 Köhler, Kreil, Wenger, Darmandieu, Graves, Haugestad, Holzen, Keller, Lloyd, Marczak, Medugorac and Rosa

Spectroscopic Investigation of the Formation of Radiolysis By-Products By 13/9 MeV Linear Accelerator of Electrons (LAE) in Salt Solutions

In the near-field chemistry of a salt repository, the radiolytically-induced redox reactions in concentrated saline solution are of particular importance because the radiolysis of saline solutions results in oxidizing chlorine-containing species, which may oxidize actinide species to higher oxidation states. If the brines are irradiated, the solutions containing radiolytic species such as hypochlorite, hypochlorous acid or hydrogen peroxide, their pH and Eh may be altered. The oxidation and complexation states of actinides, which might be present in the salt brine, will change thus influencing their speciation and consequently their mobility. Furthermore, radiolytically formed oxidizing species such as ClO- or H2O2 may enhance the corrosion of the canister material. Therefore, radiation effects on salt brines must be integrated into the database, which described the chemical processes near a disposal site. Investigations in that context usually focus on the radiation chemistry of solid NaCl however our focus is on the radiolytic products, which are formed when salt brines are irradiated by a 10 MeV linear accelerator of electrons (LAE). We attempt to quantify the irradiation-induced formation of typical radiolysis by-products such as the hypochlorite ion (OCl-) by using a 13/9 MeV LAE with doses between 120 KGy to 216 KGy while monitoring the pH of the brine solutions

Spectroscopic investigation of the formation of hypochlorite, radiolysis by-product in 5 M NaCI featuring high-energy proton beam line experiments.

Because geological salt formations are considered possible sites for radioactive waste disposal, plausible inundation scenario of salt repository will allow chloride brines to be formed, which consequently will be exposed to radiation from the waste. Key radioelements in Intermediate Level Waste (ILW),H igh Level Waste (HLW) or TRU waste have been found to be plutonium, americium, neptunium, uranium, and technetium. Therefore, the effect of radiolysis on high-saline brine under simulated repository conditions are of particular importance because it results in oxidizing chlorine-containing species, such as hypochlorite (OC1-), and hypochlorous acid (HOCI), which may oxidize actinide species to higher oxidation states. Meaningful predictions of long-term redox conditions in a nuclear repository strongly rely on estimations of G-values of the irradiation-induced formation of the oxidizers OC1- and HOCI. G-values not only depend on the total absorbed doses over the relevant timeframe, but also on the kind of irradiation involved. In fact, the G-values of hypochlorite produced by {alpha}-, {beta}-, {gamma}-, or neutron irradiation differ by an order of magnitude, depending on different LET cross-sections. To overcome the serious constrains and obstacles of conventional radiochemical work within GBq/L activity levels, we are going to simulate {alpha}-irradiation of chloride brines by the adaptation of beam-line experiments. Our long-term goal is to demonstrate how the main oxidizing chloride species such as hypochlorite caused by radiolysis may affect the overall behavior of actinides under salt repository conditions. This paper describes our first steps towards the production, the identification and the determination of these oxidizing species by beam line experiments