Table-top tunable narrow-band extreme-ultraviolet sources: from low to high-order optical harmonic generation

Ubachs, W.M.G. [Promotor

Integrated biorefinery in continuous flow systems using sustainable heterogeneous catalysts

The negative impact of crude oil on the environment has led to a necessary transition toward alternative, renewable, and sustainable resources. In this regard, lignocellulosic biomass (LCB) is a promising renewable and sustainable alternative to crude oil for the production of fine chemicals and fuels in a so-called biorefinery process. LCB is composed of polysaccharides (cellulose and hemicellulose), as well as aromatics (lignin). The development of a sustainable and economically advantageous biorefinery depends on the complete and efficient valorization of all components. Therefore, in the new generation of biorefinery, the so-called biorefinery of type III, the LCB feedstocks are selectively deconstructed and catalytically transformed into platform chemicals. For this purpose, the development of highly stable and efficient catalysts is crucial for progress toward viability in biorefinery. Furthermore, a modern and integrated biorefinery relies on process and reactor design, toward more efficient and cost-effective methodologies that minimize waste. In this context, the usage of continuous flow systems has the potential to provide safe, sustainable, and innovative transformations with simple process integration and scalability for biorefinery schemes. This thesis addresses three main challenges for future biorefinery: catalyst synthesis, waste feedstock valorization, and usage of continuous flow technology. Firstly, a cheap, scalable, and sustainable approach is presented for the synthesis of an efficient and stable 35 wt.-% Ni catalyst on highly porous nitrogen-doped carbon support (35Ni/NDC) in pellet shape. Initially, the performance of this catalyst was evaluated for the aqueous phase hydrogenation of LCB-derived compounds such as glucose, xylose, and vanillin in continuous flow systems. The 35Ni/NDC catalyst exhibited high catalytic performances in three tested hydrogenation reactions, i.e., sorbitol, xylitol, and 2-methoxy-4-methylphenol with yields of 82 mol%, 62 mol%, and 100 mol% respectively. In addition, the 35Ni/NDC catalyst exhibited remarkable stability over a long time on stream in continuous flow (40 h). Furthermore, the 35Ni/NDC catalyst was combined with commercially available Beta zeolite in a dual–column integrated process for isosorbide production from glucose (yield 83 mol%). Finally, 35Ni/NDC was applied for the valorization of industrial waste products, namely sodium lignosulfonate (LS) and beech wood sawdust (BWS) in continuous flow systems. The LS depolymerization was conducted combining solvothermal fragmentation of water/alcohol mixtures (i.e.,methanol/water and ethanol/water) with catalytic hydrogenolysis/hydrogenation (SHF). The depolymerization was found to occur thermally in absence of catalyst with a tunable molecular weight according to temperature. Furthermore, the SHF generated an optimized cumulative yield of lignin-derived phenolic monomers of 42 mg gLS-1. Similarly, a solvothermal and reductive catalytic fragmentation (SF-RCF) of BWS was conducted using MeOH and MeTHF as a solvent. In this case, the optimized total lignin-derived phenolic monomers yield was found of 247 mg gKL-1

The multifrequency behaviour of the recurrent nova RS Ophiuchi

This review concentrates on the multifrequency behaviour of RS Ophiuchi and in particular during its latest outburst. Confirmation of the 1945 outburst, bipolar outflows and its possible fate as a Type Ia Supernova are discussed.Comment: 5 pages, 5 figures, in The Golden Age of Cataclysmic Variables and Related Objects, F. Giovannelli & L. Sabau-Graziati (eds.), Mem. SAIt. 83 N.2 (in press

Sustainable sorbitol dehydration to isosorbide using solid acid catalysts: transition from batch reactor to continuous flow system

Isosorbide is one of the most interesting cellulosic-derived molecules with great potential to be implemented in wide range of products that shaping our daily life. This minireview describes the recent developments in the production of isosorbide from sorbitol in batch and continuous flow systems under hydrothermal conditions using solid acid catalysts. Moreover, we are summarizing the current hurdles and challenges that facing the synthesis of isosorbide from cellulosic biomass in continuous flow process using solid acid catalysts, as well as the scaling up of this process into pilot level, which will lead to an established industrial process with high sustainability metrics

Inibição do crescimento micelial e da germinação de esporos de Thielaviopsis paradoxa por Bacillus subtilis e Bacillus pumilus.

O objetivo do trabalho foi avaliar os efeitos de Bacillus pumilus (QST 2808) e Bacillus subtilis (QST 713) na inibição da germinação de esporos e no crescimento micelial de Thielaviopsis paradoxa, agente causal da podridão abacaxi da cana-de-açúcar. O primeiro teste avaliou a taxa de crescimento micelial do patógeno em placas de Petri, totalizando 15 placas em três tratamentos (inoculação simultânea; 24 horas e 48 horas após o bioagente). Em seguida avaliou o crescimento micelial na presença dos metabólitos produzidos pelos agentes de biocontrole, adicionados ao meio batata-dextrose-ágar, em cinco concentrações (10%; 1%; 0,1%; 0,01%; 0,001%). No teste de germinação avaliou-se o porcentual de germinação dos conídios na presença dos agentes de biocontrole nas concentrações citadas anteriormente. Ambos os agentes de biocontrole apresentaram efeitos antagônicos significativos contra o patógeno, com destaque para B. subtilis

High-order harmonic generation yielding tunable extreme-ultraviolet radiation of high spectral purity

Production of extreme-ultraviolet radiation by high-order harmonic generation is demonstrated to yield unprecedented spectral purity of λ/Δλ=2.5×105 at wavelengths covering the entire range 40–100 nm. Tunability and sub-cm-1 bandwidth of the harmonics are demonstrated in recordings of the He (1s4p) and Ar (3p53d′) resonance lines at 52.2 and 86.6 nm. Frequency shift of the harmonics due to chirp-induced phenomena are investigated and found to be small, resulting in a frequency accuracy of about 5×10-7 in the domain of extreme-ultraviolet radiation

Parathyroid tumors: Molecular signatures

Parathyroid tumors are rare endocrine neoplasms affecting 0.1–0.3% of the general population, including benign parathyroid adenomas (PAs; about 98% of cases), intermediate atypical parathyroid adenomas (aPAs; 1.2–1.3% of cases) and malignant metastatic parathyroid carcinomas (PCs; less than 1% of cases). These tumors are characterized by a variable spectrum of clinical phenotypes and an elevated cellular, histological and molecular heterogeneity that make it difficult to pre-operatively distinguish PAs, aPAs and PCs. Thorough knowledge of genetic, epigenetic, and molecular signatures, which characterize different parathyroid tumor subtypes and drive different tumorigeneses, is a key step to identify potential diagnostic biomarkers able to distinguish among different parathyroid neoplastic types, as well as provide novel therapeutic targets and strategies for these rare neoplasms, which are still a clinical and therapeutic challenge. Here, we review the current knowledge on gene mutations and epigenetic changes that have been associated with the development of different clinical types of parathyroid tumors, both in familial and sporadic forms of these endocrine neoplasms

Congenital metabolic bone disorders as a cause of bone fragility

Bone fragility is a pathological condition caused by altered homeostasis of the mineralized bone mass with deterioration of the microarchitecture of the bone tissue, which results in a reduction of bone strength and an increased risk of fracture, even in the absence of high-impact trauma. The most common cause of bone fragility is primary osteoporosis in the elderly. However, bone fragility can manifest at any age, within the context of a wide spectrum of congenital rare bone metabolic diseases in which the inherited genetic defect alters correct bone modeling and remodeling at different points and aspects of bone synthesis and/or bone resorption, leading to defective bone tissue highly prone to long bone bowing, stress fractures and pseudofractures, and/or fragility fractures. To date, over 100 different Mendelian-inherited metabolic bone disorders have been identified and included in the OMIM database, associated with germinal heterozygote, compound heterozygote, or homozygote mutations, affecting over 80 different genes involved in the regulation of bone and mineral metabolism. This manuscript reviews clinical bone phenotypes, and the associated bone fragility in rare congenital metabolic bone disorders, following a disease taxonomic classification based on deranged bone metabolic activity