The present study provides insights into the manner in which the configuration of β‐aminoallene precursors affects their gold‐catalyzed cyclization reactions. The reactivity can be switched by using ...indolizidinone‐tethered β‐aminoallenes bearing the syn‐ or the anti‐disposition of both protons at the α‐ and β‐allenic stereocenters. Fused heterocycles (seven examples, 60–75% yields) are obtained from the syn‐precursors, while a dimerization–aminoketalization–spirocyclization sequence to afford benzobpyrrolo3,2,1‐ij1,7naphthyridin‐1‐ones (four examples, 34–48% yields) can be achieved starting from their anti‐isomers.
The development of reactive-separation processes, in which products are separated from the reaction media (i.e., reactants and catalysts) in a single reaction unit, is of great interest in industry ...as energy-intensive separation processes can be obviated. One promising alternative to accomplish this process intensification is the utilization of biphasic emulsion systems, where products and reactants can be separated based on differences in solubility. Additionally, when solid nanoparticles with amphiphilic character and catalytic activity are employed in biphasic systems, it is possible to simultaneously stabilize the liquid–liquid interface and catalyze chemical reactions. This new technology leads to (a) increased interfacial area, (b) enhanced mass transfer of molecules between the two phases, (c) simplified reaction/separation processes by using a recoverable solid catalyst instead of surfactants, and (d) effective separation of products from the reaction mixture by differences in their water/oil solubility and thus avoiding distillation that leads to product decomposition. To this end, the present tutorial review explores the fundamentals of Pickering interfacial catalysis (PIC) and its application in biomass upgrading (upgrading of sugars and pyrolysis oil), biogas to liquid products via Fischer–Tropsch synthesis, and biodiesel production in the context of the United Nations sustainable development goals. We conclude this contribution with an outlook of the current bottlenecks in the commercial exploitation of the technology and the possible future directions in which PIC can be employed to facilitate the energy transition and the C-circular economy.
The synthesis of fuel-range molecules by condensation of biomass-derived furfural and acetone has been studied in a biphasic emulsion system. Nanohybrids composed of basic oxide nanoparticles fused ...to carbon nanotubes have been used to simultaneously stabilize water/oil emulsions and catalyze the condensation reaction. Under the same conditions, higher conversions and higher fractions of fuel-range condensation products (C
8
–C
13
) have been obtained in the emulsion compared to those obtained in the single phase. Furthermore, when using metallized nanohybrids these emulsions have been used to hydrogenate the oil-soluble condensation products. Both model compounds and synthetic bio-oil mixtures have been used to demonstrate that catalytic emulsion systems could be effective for upgrading complex mixtures, such as pyrolysis oil.
Passerini (P-3CR) and Passerini–Smiles reactions were investigated in azetidine-2,3-diones, affording the corresponding 3,3-disubstituted-β-lactams with complete diastereoselectivity in high yields. ...The study has been carried out using different isocyanides, carboxylic acids, and phenols showing the scope of both reactions. In addition, the regioselective synthesis of highly functionalized β-lactam-triazole hybrids has been developed via a Passerini/CuAAC sequence. Interestingly, the use of dialkynes/diazides or trialkynes/triazides as linkers in the CuAAC step has allowed the synthesis of C 2 and C 3 symmetric β-lactam-triazole hybrids, respectively.
Nowadays, biodiesel has become a very promising alternative to fossil diesel fuel, regarding environmental concerns and fuel resource depletion. Biodiesel is usually produced through homogeneous or ...heterogeneous transesterification of different fatty raw materials. Although main research has been carried out with homogenous catalysts, heterogeneous catalysts may be of interest due to ease of recovery and recycling, as well as readiness for continuous processing. In this work, calcined Mg-Al hydrotalcite (HT) was used for the heterogeneous transesterification of waste cooking oil. Three reaction parameters, namely, reaction time, amount of catalyst, and methanol-to-oil molar ratio, were optimized by means of Response Surface Methodology (RSM) at constant temperature (65 °C), using a Box-Behnken design. Optimal fatty acid methyl ester (FAME) content (86.23% w/w FAME/sample) was predicted by the model with an R-squared value of 98.45%, using 3.39 g of HT (8.5% w/w oil) and an 8:1 methanol-oil molar ratio, for a duration of 3.12 h. It was observed that calcination of HT, while avoiding the previous washing step, allowed the presence of chemical species that enhanced the effect of the catalyst. It can be concluded from this field trial that calcined and nonwashed Mg-Al hydrotalcite may be considered an effective basic catalyst for the production of biodiesel from waste cooking oil. Also, RSM proved to be a useful tool for predicting biodiesel yield.
The search for experimental models mimicking an early stage of Parkinson's disease (PD) before motor manifestations is fundamental in order to explore early signs and get a better prognosis. ...Interestingly, our previous studies have indicated that 6-hydroxydopamine (6-OHDA) is a suitable model to induce an early degeneration of the nigrostriatal system without any gross motor impairment. Considering our previous findings, we aim to implement a novel system to monitor rats after intrastriatal injection of 6-OHDA to detect and analyze physiological changes underlying prodromal PD. Twenty male Sprague-Dawley rats were unilaterally injected with 6-OHDA (
= 10) or saline solution (
= 10) into the right striatum and placed in enriched environment cages where the activity was monitored. After 2 weeks, the amphetamine test was performed before the sacrifice. Immunohistochemistry was developed for the morphological evaluation and western blot analysis to assess molecular changes. Home-cage monitoring revealed behavioral changes in response to 6-OHDA administration including significant hyperactivity and hypoactivity during the light and dark phase, respectively, turning out in a change of the circadian timing. A preclinical stage of PD was functionally confirmed with the amphetamine test. Moreover, the loss of tyrosine hydroxylase expression was significantly correlated with the motor results, and 6-OHDA induced early proapoptotic events. Our findings provide evidence for a novel prodromal 6-OHDA model following a customized monitoring system that could give insights to detect non-motor deficits and molecular targets to test neuroprotective/neurorestorative agents.
Nowadays, smart environments (SEs) enable the monitoring of people with physical disabilities by incorporating activity recognition. Thermal cameras are being incorporated as they preserve privacy. ...Some deep learning (DL) solutions use the pose of the users because it removes external noise. Although there are robust DL solutions in the visible spectrum (VS), they fail in the thermal domain. Thus, we propose thermal human pose lite (THPoseLite), a convolutional neural network (CNN) based on MobileNetV2 that extracts pose from thermal images (TIs). In a novel way, an auto-labeling approach has been developed. It includes a background removal using an optical flow estimator. It also integrates Blazepose a pose estimator for VS images (VSIs) to obtain the poses in the preprocessed TIs. Results show that the preprocessing increases the percentage of detected poses by Blazepose from 19.55% to 76.85%. This allows the recording of human pose estimation (HPE) data sets in the VS without requiring VS cameras or manually annotating data sets. Furthermore, THPoseLite has been embedded in an Internet of Things (IoT) device incorporating an edge tensor processing unit (TPU) accelerator, which can process TIs recorded at 9 frames per second (FPS) in real time (12.28 FPS). It requires fewer than 6W of energy to run. It has been achieved using model quantization, decreasing the accuracy in estimating the poses by only 1%. The mean-squared error of MobileNetV2 in test images is 35.48, obtaining accurate poses in 21% of the images that Blazepose is not able to detect any pose.
This study examined the co-immobilization of the cyanobacterium
Synechococcus elongatus
with the plant growth-promoting bacterium
Azospirillum brasilense
in alginate beads and its potential ...application for the removal of phosphorus from aquaculture wastewater. Co-immobilization of both microorganisms significantly increased the cell density of
S. elongatus
(2852.5 × 10
4
cells mL
−1
) compared with that of immobilization of cyanobacteria alone (1325.2 × 10
4
cells mL
−1
). Chlorophyll
a
content was similar in co-immobilized (11.1 ± 3.5 pg cell
−1
) and immobilized
S. elongatus
(14.5 ± 4.9 pg cell
−1
).
Azospirillum brasilense
showed continuous growth until day 2, after which its cell concentration declined until the end of the assay. Co-immobilized
S. elongatus
removed more phosphorus (44.8 %) than immobilized cyanobacteria cells alone (32.0 %). In conclusion, phosphate removal was greater with free cells of
S. elongatus
but overlapped with the values that were obtained with the treatment of co-immobilization of cells. Our results demonstrate that
A. brasilense
enhances the growth of
S. elongatus
and improves its removal of phosphorus when they are co-immobilized in alginate beads compared with only immobilization of cyanobacteria cells alone.
Passerini (P-3CR) and Ugi (U-4CR) reactions were investigated in 4-oxoazetidine-2-carboxaldehydes, affording the corresponding Passerini and Ugi adducts with moderate diastereoselectivity in high ...yields. Fortunately, the obtained mixtures of isomers syn/anti were separated in most cases. The scope of both IMCRs has been studied using a variety of isocyanides, carboxylic acids and amines. Ugi adducts were used for the preparation of unusual 2-azetidinones fused to medium-sized rings via RCM. In addition, β-lactam-diketopiperazine hybrids have also been prepared from the corresponding Ugi adducts.
Non-alcoholic fatty liver disease (NAFLD) is associated with post-operative liver failure (PLF) and impaired liver regeneration. We investigated the effects of a glucagon-like peptide-1 (GLP-1) ...receptor agonist on NAFLD, PLF and liver regeneration in mice fed chow diet or methionine/choline-deficient diet (MCD) or high fat diet (HFD). Fc-GLP-1 decreased transaminases, reduced intrahepatic triglycerides (TG) and improved MCD-induced liver dysfuction. Macrophage/Kupffer cell-related markers were also reduced although Fc-GLP-1 increased expression of genes related to natural killer (NK), cytotoxic T lymphocytes and hepatic stellate cell (HSC) activation. After partial hepatectomy (PH), survival rates increased in mice receiving Fc-GLP-1 on chow or MCD diet. However, the benefit of Fc-GLP-1 on NASH-like features was attenuated 2 weeks post-PH and liver mass restoration was not improved. At this time-period, markers of NK cells and cytotoxic T lymphocytes were further elevated in Fc-GLP-1 treated mice. Increased HSC related gene expression in livers was observed together with decreased retinyl ester content and increased retinal and retinoic acid, reflecting HSC activation. Similar effects were found in mice fed HFD receiving Fc-GLP-1. Our results shed light on the differential effects of a long-acting GLP-1R agonist in improving NAFLD and PLF, but not enhancing liver regeneration in mice.
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