Can energetic terahertz pulses initiate surface catalytic reactions on the picosecond time scale?

In preparation for picosecond pump-probe experiments at the SwissFEL X-ray laser facility, the feasibility of collectively initiating surface chemical reactions using energetic pulses of terahertz radiation is being tested.     

How Important Are Genes to Achieve Longevity?

Several studies on the genetics of longevity have been reviewed in this paper. The results show that, despite efforts and new technologies, only two genes, APOE and FOXO3A, involved in the protection of cardiovascular diseases, have been shown to be associated with longevity in nearly all studies. This happens because the genetic determinants of longevity are dynamic and depend on the environmental history of a given population. In fact, population-specific genes are thought to play a greater role in the attainment of longevity than those shared between different populations. Hence, it is not surprising that GWAS replicated associations of common variants with longevity have been few, if any, as these studies pool together different populations. An alternative way might be the study of long-life families. This type of approach is proving to be an ideal resource for uncovering protective alleles and associated biological signatures for healthy aging phenotypes and exceptional longevity.     

The gas—solid trickle-flow reactor for the catalytic oxidation of hydrogen sulphide: A trickle-phase model

The oxidation of H₂S by O₂ producing elemental sulphur has been studied at temperatures of 100–300°C and at atmospheric pressure in a laboratory-scale gas-solid trickle-flow reactor. In this reactor one of the reaction products, i.e. sulphur, is removed continuously by flowing solids. A porous, free-flowing catalyst carrier has been used which contains a NaX zeolite acting as a catalyst as well as a sulphur adsorbent. In order to describe mass transfer in the trickle-flow reactor, a reactor model has been developed in which a particle-free, upflowing gas phase and a dense, downflowing gas-solids suspension, the so-called trickle phase, are distinguished. Within the trickle phase, diffusion of the reactants parallel to reaction in the catalyst particles takes place. The mass transfer rate from the gas phase to the trickle phase has been evaluated by the reaction of H₂S with SO₂, which is a much faster reaction than the reaction with O₂. From the experiments and from the reactor model calculations it appears that for the H₂S-O₂ reaction no mass transfer limitations occur at temperatures up to about 200°C, whereas at 300°C gas-phase mass transfer and diffusion within the dense solids suspension offer resistance to reaction.     

How to Respond to New Standard of Compound Rubber in Rubber Industry?

<正>On December 31,2014,General Technical Specification of Compound Rubber,a recommended national standard,was formally released and will be officially implemented on July 1.It is confirmed that compound rubber shall not contain more than 88%raw rubber.However,the agricultural reclamation     

The refined e-NRTL model applied to CO2–H2O–alkanolamine systems

The electrolyte NRTL (e-NRTL) model by Chen (1982) and Chen and Evans (1986) is perhaps the most commonly used activity coefficient based thermodynamic model for industrial systems. It has been shown by Bollas et al. (2008) that the original e-NRTL model is inconsistent for systems with multiple cations and/or anions, in the same work the model equations for the so-called refined e-NRTL model were given. In this work the refined e-NRTL model is applied to CO₂–H₂O–alkanolamine systems. The interaction parameters of the refined e-NRTL model are regressed to partial pressure of CO₂, binary vapour–liquid-equilibrium, freezing point depression data and excess enthalpy data. The model is in the end used to predict partial pressures and speciation for the CO₂–H₂O–MEA and CO₂–H₂O–MDEA systems.     

Molten Salts Are Promising Catalysts. How to Apply in Practice?

A diesel soot filter with a Cs₂SO₄V₂O₅ molten salt diesel soot oxidation catalyst has been developed. An engine test-bench was used to test it in diesel exhaust gas with ELPI analysis and to deposit diesel soot on filters for temperature programmed oxidation experiments. Molten salt (Cs₂SO₄V₂O₅) based catalytic foam has an onset temperature for catalytic oxidation of 320°C. This is a promising temperature for continuous filter-regeneration applications. Unfortunately the liquid state of the catalyst makes it unfit for the very effective wall-flow monolith filter, and necessitates the use of a foam filter as support. The onset temperature of the catalytic foam of 320°C is still too high to justify a change from wall-flow monolith to foam, as ceramic foam is a less effective filter than the wall-flow monolith. Foams are no absolute filters, and should be optimized for each application.     

Self-Assembled Structures of Catanionic Associations: How to Optimize Vesicle Formation?

Like other amphiphilic compounds, bolaforms do not always possess surfactant properties; it depends on the spacer chain length and the nature of the polar head group (both sufficiently hydrophobic or hydrophilic, respectively, to intensify the amphiphilic properties). In this regard, unsymmetrical bolaamphiphiles bearing a sugar polar head group and a carboxylic acid function at the opposite ends of a hydrophobic binding spacer were synthesized. These biocompatible sugar-derived bolaforms were associated with basic fatty amines, by an acid–base reaction, to obtain catanionic mixtures. Associations with 1,7-lactobionamidoheptanoic acid and decylamine or octylamine spontaneously form stable 200–600 nm vesicles. This new type of association may find an application in drug delivery since catanionic vesicles can transport active substances inside the hydrophilic core, as well as hydrophobic drugs within the bilayer.     

How to increase the hydration degree of CA — The influence of CA particle fineness

It is shown that the hydration degree of CA is directly dependent on the fineness of CA-particles. Finer particles lead to an increased degree of hydration and also an increased hydration rate.The reaction of a sample with mainly coarse particles of CA (d₅₀ = 50 μm) is characterized by a low hydration rate and only 34 rel.-% of CA dissolved after 22 h. Whereas in a very fine CA-sample (d₅₀ = 4 μm) hydration starts delayed but then shows the highest hydration rate and a dissolution of 62 rel.-% CA. The behaviour is explained by the coverage of CA-particles with a dense hydrate layer of C₂AH_x and AH_x. This reacted CA-rim is supposed to have the same thickness for different sized CA-particles. Optimization of Gauss distribution curves, which were applied to simulate a more realistic particle size distribution, leads to a reacted rim thickness of 1.3 μm until reaction is stopped.     

The Multiverse of Plant Small RNAs: How Can We Explore It?

Plant small RNAs (sRNAs) are a heterogeneous group of noncoding RNAs with a length of 20–24 nucleotides that are widely studied due to their importance as major regulators in various biological processes. sRNAs are divided into two main classes—microRNAs (miRNAs) and small interfering RNAs (siRNAs)—which differ in their biogenesis and functional pathways. Their identification and enrichment with new structural variants would not be possible without the use of various high-throughput sequencing (NGS) techniques, allowing for the detection of the total population of sRNAs in plants. Classifying sRNAs and predicting their functional role based on such high-performance datasets is a nontrivial bioinformatics task, as plants can generate millions of sRNAs from a variety of biosynthetic pathways. Over the years, many computing tools have been developed to meet this challenge. Here, we review more than 35 tools developed specifically for plant sRNAs over the past few years and explore some of their basic algorithms for performing tasks related to predicting, identifying, categorizing, and quantifying individual sRNAs in plant samples, as well as visualizing the results of these analyzes. We believe that this review will be practical for biologists who want to analyze their plant sRNA datasets but are overwhelmed by the number of tools available, thus answering the basic question of how to choose the right one for a particular study.     

How different dopants leads to difference in photocatalytic activity in doped TiO2?

This study explores the significance of dopant location in a doped TiO₂ nanostructure in ascertaining its photocatalytic properties. The un-doped TiO₂, boron-doped TiO₂ (B–TiO₂) and nitrogen-doped TiO₂ (N–TiO₂) photocatalysts were synthesized (with variable dopant concentrations) via sol-gel method. The photocatalysts were further characterized for structural, surface, and physico-chemical properties in reference to their influence on photocatalytic properties. The results of X-ray diffraction (XRD), micro Raman, Energy dispersive X-ray technique (EDX), X-ray photoelectron spectroscopy (XPS), and Fourier Transform infrared spectroscopy (FTIR) confirmed the existence of B and N atoms in the TiO₂ crystal lattice. The results also indicated that the B and N doping promoted the formation of rutile phase in doped TiO₂. Further, B doping leads to decrease in the surface area whereas N doping leads to increase in surface area of TiO₂. The UV–Vis DRS analysis revealed that a red shift in absorption band edge occurs upon B and N doping. The band gap values also decreased to 2.96 and 2.27 eV in B–TiO₂ and N–TiO₂, respectively in comparison to 2.98 for un-doped TiO₂. The photocatalytic degradation studies of diclofenac sodium (DCLF) were conducted to examine the effect of dopant role on the efficiency of doped photocatalyst. B–TiO₂ exhibited maximum photocatalytic activity by degrading 98% of DCLF in comparison to N–TiO₂, which showed 95% degradation.     

Exercise-Induced Adipose Tissue Thermogenesis and Browning: How to Explain the Conflicting Findings?

Brown adipose tissue (BAT) has been widely studied in targeting against metabolic diseases such as obesity, type 2 diabetes and insulin resistance due to its role in nutrient metabolism and energy regulation. Whether exercise promotes adipose tissue thermogenesis and browning remains controversial. The results from human and rodent studies contradict each other. In our opinion, fat thermogenesis or browning promoted by exercise should not be a biomarker of health benefits, but an adaptation under the stress between body temperature regulation and energy supply and expenditure of multiple organs. In this review, we discuss some factors that may contribute to conflicting experimental results, such as different thermoneutral zones, gender, training experience and the heterogeneity of fat depots. In addition, we explain that a redox state in cells potentially causes thermogenesis heterogeneity and different oxidation states of UCP1, which has led to the discrepancies noted in previous studies. We describe a network by which exercise orchestrates the browning and thermogenesis of adipose tissue with total energy expenditure through multiple organs (muscle, brain, liver and adipose tissue) and multiple pathways (nerve, endocrine and metabolic products), providing a possible interpretation for the conflicting findings.     

Functional Precision Oncology: The Next Frontier to Improve Glioblastoma Outcome?

Glioblastoma remains the most malignant and intrinsically resistant brain tumour in adults. Despite intensive research over the past few decades, through which numerous potentially druggable targets have been identified, virtually all clinical trials of the past 20 years have failed to improve the outcome for the vast majority of GBM patients. The observation that small subgroups of patients displayed a therapeutic response across several unsuccessful clinical trials suggests that the GBM patient population probably consists of multiple subgroups that probably all require a distinct therapeutic approach. Due to extensive inter- and intratumoral heterogeneity, assigning the right therapy to each patient remains a major challenge. Classically, bulk genetic profiling would be used to identify suitable therapies, although the success of this approach remains limited due to tumor heterogeneity and the absence of direct relationships between mutations and therapy responses in GBM. An attractive novel strategy aims at implementing methods for functional precision oncology, which refers to the evaluation of treatment efficacies and vulnerabilities of (ex vivo) living tumor cells in a highly personalized way. Such approaches are currently being implemented for other cancer types by providing rapid, translatable information to guide patient-tailored therapeutic selections. In this review, we discuss the current state of the art of transforming technologies, tools and challenges for functional precision oncology and how these could improve therapy selection for GBM patients.     

The Mitochondrial Epigenome: An Unexplored Avenue to Explain Unexplained Myopathies?

Mutations in either mitochondrial DNA (mtDNA) or nuclear genes that encode mitochondrial proteins may lead to dysfunctional mitochondria, giving rise to mitochondrial diseases. Some mitochondrial myopathies, however, present without a known underlying cause. Interestingly, methylation of mtDNA has been associated with various clinical pathologies. The present study set out to assess whether mtDNA methylation could explain impaired mitochondrial function in patients diagnosed with myopathy without known underlying genetic mutations. Enhanced mtDNA methylation was indicated by pyrosequencing for muscle biopsies of 14 myopathy patients compared to four healthy controls, at selected cytosines in the Cytochrome B (CYTB) gene, but not within the displacement loop (D-loop) region. The mtDNA methylation patterns of the four healthy muscle biopsies were highly consistent and showed intriguing tissue-specific differences at particular cytosines with control skin fibroblasts cultured in vitro. Within individual myopathy patients, the overall mtDNA methylation pattern correlated well between muscle and skin fibroblasts. Despite this correlation, a pilot analysis of four myopathy and five healthy fibroblast samples did not reveal a disease-associated difference in mtDNA methylation. We did, however, detect increased expression of solute carrier family 25A26 (SLC25A26), encoding the importer of S-adenosylmethionine, together with enhanced mtDNA copy numbers in myopathy fibroblasts compared to healthy controls. To confirm that pyrosequencing indeed reflected DNA methylation and not bisulfite accessibility, mass spectrometry was employed. Although no myopathy-related differences in total amount of methylated cytosines were detected at this stage, a significant contribution of contaminating nuclear DNA (nDNA) was revealed, and steps to improve enrichment for mtDNA are reported. In conclusion, in this explorative study we show that analyzing the mitochondrial genome beyond its sequence opens novel avenues to identify potential molecular biomarkers assisting in the diagnosis of unexplained myopathies.     

How good would the conductivity of graphene have to be to make single-layer-graphene metamaterials for terahertz frequencies feasible?

Various terahertz metamaterial devices and concepts involving graphene have been introduced in the literature, however, graphene is either a functional add-on to resonators made from metals with a high electrical conductivity, or it is studied as arrays of relatively simple plasmonic stripes or disks, made from single- or multi-layer graphene. Graphene is never the resonator material of more complex structures such as split-ring resonators because its conductivity is too low. However, for electromagnetic chemical sensors, even a moderate conductivity may be adequate since the response of the metamaterial can be strongly modified by the adsorption of molecules, not only by a change of the dielectric environment, as for conventional metamaterials, but also via a direct change of the conductivity. Here, we consider a prototypical split-ring-resonator consisting of a single layer of patterned graphene on a dielectric, and investigate by simulations its terahertz reflectivity response. The crucial material parameters for device performance are the charge carrier density, controlled by the Fermi energy, and the Drude scattering time. We find that metamaterial behavior becomes interesting if the Drude scattering time of 0.1 ps of standard graphene could be raised to the theoretically accessible value of 0.4–0.5 ps.