Integrated membrane operations in the ethylene oxide production

Petrochemical industry, highly energy and capital intensive, might significantly benefit from the implementation of membrane operations for meeting stringent environmental standards, controlling production cost and final product's quality. Membrane units have been proved effective for improving the efficiency of different industrial productions. Ethylene oxide (EO), an important petrochemical intermediate, is produced by selective catalytic oxidation of ethylene, a valuable hydrocarbon feedstock. In this study, the EO manufacturing cycle is redesigned by integrating different membrane operations. Both the conversion and separation sections of the plant are investigated, considering the use of membrane reactors (MRs) for the separate feeding of the oxidant, membrane contactors (MCs) for the absorption of EO and carbon dioxide, and gas separation (GS) membrane units for the hydrocarbon recovery before their being recycled to the reactor. Design considerations are provided, and the benefits coming from each membrane operation, as well as from their synergic integration, are outlined with particular attention to environmental impact, raw materials and energy consumption.     

Discovery of an Allosteric Ligand Binding Site in SMYD3 Lysine Methyltransferase

SMYD3 is a multifunctional epigenetic enzyme with lysine methyltransferase activity and various interaction partners. It is implicated in the pathophysiology of cancers but with an unclear mechanism. To discover tool compounds for clarifying its biochemistry and potential as a therapeutic target, a set of drug-like compounds was screened in a biosensor-based competition assay. Diperodon was identified as an allosteric ligand; its R and S enantiomers were isolated, and their affinities to SMYD3 were determined (K_D=42 and 84 μM, respectively). Co-crystallization revealed that both enantiomers bind to a previously unidentified allosteric site in the C-terminal protein binding domain, consistent with its weak inhibitory effect. No competition between diperodon and HSP90 (a known SMYD3 interaction partner) was observed although SMYD3–HSP90 binding was confirmed (K_D=13 μM). Diperodon clearly represents a novel starting point for the design of tool compounds interacting with a druggable allosteric site, suitable for the exploration of noncatalytic SMYD3 functions and therapeutics with new mechanisms of action.     

Putative Circulating MicroRNAs Are Able to Identify Patients with Mitral Valve Prolapse and Severe Regurgitation

Mitral valve prolapse (MVP) associated with severe mitral regurgitation is a debilitating disease with no pharmacological therapies available. MicroRNAs (miRNA) represent an emerging class of circulating biomarkers that have never been evaluated in MVP human plasma. Our aim was to identify a possible miRNA signature that is able to discriminate MVP patients from healthy subjects (CTRL) and to shed light on the putative altered molecular pathways in MVP. We evaluated a plasma miRNA profile using Human MicroRNA Card A followed by real-time PCR validations. In addition, to assess the discriminative power of selected miRNAs, we implemented a machine learning analysis. MiRNA profiling and validations revealed that miR-140-3p, 150-5p, 210-3p, 451a, and 487a-3p were significantly upregulated in MVP, while miR-223-3p, 323a-3p, 340-5p, and 361-5p were significantly downregulated in MVP compared to CTRL (p ≤ 0.01). Functional analysis identified several biological processes possible linked to MVP. In addition, machine learning analysis correctly classified MVP patients from CTRL with high accuracy (0.93) and an area under the receiving operator characteristic curve (AUC) of 0.97. To the best of our knowledge, this is the first study performed on human plasma, showing a strong association between miRNAs and MVP. Thus, a circulating molecular signature could be used as a first-line, fast, and cheap screening tool for MVP identification.     

Sources and mitigation of methane emissions by sectors: A critical review

The environmental community rightly recognizes global warming as one of the gravest threats to the planet. Methane (CH₄), one of the greenhouse gases causing global warming, is emitted from a variety of sources and its concentration in atmosphere has increased dramatically over the last few centuries. Therefore, the increasing concentrations of methane are of special concern because of its effects on climate and atmospheric chemistry. Anthropogenic sources of methane can be collected under the titles of agriculture, energy, waste and industry on the basis of sectors. This paper aims at examining the past trends in emissions, the sources and mitigation strategies of the methane. As a result of the study, it is determined that the agricultural sector is the biggest source of methane emissions among the sectors. The energy, waste and industry follow the agricultural sources respectively.     

Direct Application of Rep‐PCR on Type I Sourdough Matrix to Monitor the Dominance and Persistence of a Lactobacillus plantarum Starter Throughout Back‐Slopping

This study describes the optimization and application of repetitive element‐PCR (rep‐PCR) technique directly on microbial DNA extracted from type I sourdoughs for fast monitoring of a Lb. plantarum starter strain (P1FMC) throughout daily back‐slopping. The challenge was to follow and study the performance of a starter culture directly in sourdoughs without cultivation on selective media. The extraction of good quality microbial DNA suitable for amplification from a complex matrix such as dough was the first target. In addition, the objective to obtain a clear rep‐PCR profile referable to a specific starter strain among a microbial community was pursued. Co‐inoculum trials, in flour matrix, with Lb. plantarum P1FMC and L. lactis LC71 strains and, subsequently, type I sourdough back‐slopping trials were performed. The rep‐PCR amplification profiles obtained were clearly referable to that of Lb. plantarum P1FMC starter in both co‐inoculum trials (also when it was present with one order of magnitude less with respect to L. lactis LC71) and back‐slopping trials where it dominated the fermentation process with loads of 10⁸ cfu g^?1 and prevailed on the autochthonous microbiota. Thus, the approach proposed in this paper could be considered a methodological advancement, based on a culture‐independent one‐step rep‐PCR, suitable for fast monitoring of starter performance.     

Uncertainties in estimating the roughness coefficient of rock fracture surfaces

Joint roughness has a critical role in the deformation behavior of discontinuous rock masses. Several subjective (visual comparison) and quantitative (statistical and fractal) approaches have been proposed for estimating rock joint roughness coefficient (JRC). Using a large collection of 223 published joint profiles, this study investigates variability of the JRC estimates by these approaches. Among the profile parameters, maximum height (R _z), ultimate slope (λ), and fractal dimension (D _h–L, determined using the hypotenuse leg method) show a lower sensitivity to the sampling interval than the root mean square of the first deviation (Z ₂), profile elongation index (δ), fractal dimension (D _c, determined using the compass-walking method), and standard deviation of the angle i (σ _i ). Accordingly, this study proposes two separate sets of equations for quantitatively estimating JRC. The performances of these equations are examined by performing direct shear tests on 23 rock joint samples. The subjective approach is found to underestimate JRC by less than two units because it ignores (1) the main trend of the compared profile and (2) the limited scope of the standard profiles. Following these results, the visual comparison chart is updated by explicitly adding a scale bar for the y-axes of the standard profiles. Several basic rules for visual comparisons are also proposed.

     

Intrinsic Fluorescence of the Active and the Inactive Functional Forms of Human Thymidylate Synthase

The observables associated with protein intrinsic fluorescence – spectra, time decays, anisotropies – offer opportunities to monitor in real time and non-invasively a protein‘s functional form and its interchange with other forms with different functions. We employed these observables to sketch the fluorometric profiles of two functional forms of human thymidylate synthase (hTS), a homodimeric enzyme crucial for cell proliferation and thus targeted by anticancer drugs. The protein takes an active and an inactive form. Stabilization of the latter by peptides that, unlike classical hTS inhibitors, bind it at the monomer/monomer interface offers an alternative inhibition mechanism that promises to avoid the onset of drug resistance in anticancer therapy. The fluorescence features depicted herein can be used as tools to identify and quantify each of the two protein forms in solution, thus making it possible to investigate the kinetic and thermodynamic aspects of the active/inactive conformational interchange. Two examples of fluorometrically monitored interconversion kinetics are provided.