(3S,4R)-3,4-Dihydroxy-N-alkyl-l-homoprolines: synthesis and computational mechanistic studies.

This is the first synthetic report of (3S,4R)-dihydroxy-N-alkyl-l-homoprolines described so far. 2,4-O-Benzylidene-d-erythrose was obtained from d-glucose with an improved yield, and then transformed into the title (3S,4R)-dihydroxy-N-alkyl-l-homoprolines, in a two-step strategy, with excellent overall yields. Hydrogenolysis of the benzyl group led to the NH congener. The synthesis of final products from 1,4-lactone intermediates was studied by computational means either under acidic or basic conditions. The theoretical mechanism studies fully explain the experimental results: (a) an equilibrium between l-homoprolines and their bicyclic counterparts is established in acids; (b) the equilibrium suffers a complete displacement towards the l-homoproline side in a basic medium.

Total Stereoselective Michael Addition of N- and S- Nucleophiles to a d-Erythrosyl 1,5-Lactone Derivative. Experimental and Theoretical Studies Devoted to the Synthesis of 2,6-Dideoxy-4-functionalized-d- ribono-hexono-1,4-lactone.

The synthesis of a 1,5-lactone 2,4- O-alkylidene-d-erythrose derivative was found to be a highly stereoselective template in Michael addition trough the reaction of a d-erythrosyl 1,5-lactone derivative with nitrogen and sulfur nucleophiles. The sulfur adducts formed are 1 (d-erythrose derivative):1 (nucleophile), and the nitrogen adducts are 1:2. Both were then treated under HCl to give 2,6-dideoxy-4-functionalized-d- ribono-hexono-1,4-lactone by a reaction cascade in high overall yield. Reaction's scale up even improves the yield. The theoretical and computational results clearly explain the origin of the stereoselectivity, and the energetic course of reactions starting with nitrogen and sulfide nucleophiles. Considering that the 1,4-lactones obtained in this work offer a new molecular scaffold for organic synthesis, these new results provide a solid theoretical platform that can be used to speed up synthesis of other derivatives in a stereo- and regioselective way.

Lipase-Catalysed Polymerization of Eutectic Mixtures.

Aiming to reduce the toxicity and operational costs often associated to chemical processes, the enzymatic synthesis is applied herein as a sustainable route for producing polyesters. The use of NADES' (Natural Deep Eutectic Solvents) components as a source of monomers for the synthesis of polymers through lipase-catalyzed esterification in an anhydrous medium is detailed for the first time. Three NADES composed by glycerol and an organic base, or acid, were used to produce polyesters, through polymerization reactions catalyzed by Aspergillus oryzae lipase. High polyester conversion rates (above 70 %), containing at least 20 monomeric units (glycerol:organic acid/base (1 : 1)), were observed by matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) analysis. The NADES monomers' capacity for polymerization, along with their non-toxicity, cheap cost, and simplicity of production, sets up these solvents as a greener and cleaner approach for the synthesis of high value-added products.

Deep Eutectic Solvents as Suitable Solvents for Lipase-Catalyzed Transesterification Reactions.

In this work, three deep eutectic mixtures (DES 1: choline chloride/urea; DES 2: choline chloride/glycerol; and DES 3: tetrabutylammonium bromide/imidazole) were investigated as mediums for the synthesis of glucose laurate and glucose acetate. Aiming to achieve a greener and more sustainable approach, the synthesis reactions were catalyzed by lipases from Aspergillus oryzae (LAO), Candida rugosa (LCR), and porcine pancreas (LPP). The hydrolytic activity of lipases against p-nitrophenyl hexanoate revealed no evidence of enzyme inactivation when DES were used as medium. Regarding the transesterification reactions, combining LAO or LCR with DES 3 resulted in the efficient production of glucose laurate (from glucose and vinyl laurate) (conversion >60 %). The best result for LPP was observed in DES 2, with 98 % of product production after 24 hours of reaction. When replacing vinyl laurate by a smaller hydrophilic substrate, vinyl acetate, a distinct behavior was observed. LCR and LPP performed better in DES 1, yielding more than 80 % of glucose acetate after 48 hours of reaction. The catalytic activity of LAO was less pronounced, reaching only nearly 40 % of product in DES 3. The results highlight the potential of combining biocatalysis with greener and environmentally-safer solvents, for the synthesis of differentiated chain-length sugar fatty acid esters (SFAE).

Laccase-Catalyzed Synthesis of Added-Value Polymers from Cork and Grape Extracts.

The development of products from natural plant sources, including agriculture and food wastes, contributes significantly to the circular economy and global sustainability. Cork and grape wastes were employed as the primary sources in this study to obtain compounds of interest under mild extraction conditions. Laccase was applied to oxidize the cork and grape extracts, with the aim of producing value-added molecules with improved properties. Ultraviolet-visible (UV-vis) spectroscopy was assessed to monitor the oxidation process, and characterization of the end products was performed by matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) spectroscopy. The antioxidant and antiaging properties were evaluated by means of ABTS, DPPH, FRAP, and SPF testing. Overall, as compared to their monomeric counterparts, the polymeric compounds displayed remarkable antioxidant and antiaging characteristics after laccase oxidation, showing tremendous potential for applications in the food, pharmaceutical, cosmetic, and textile industries.

Femoral nerve block with selective tibial nerve block provides effective analgesia without foot drop after total knee arthroplasty: a prospective, randomized, observer-blinded study.

BACKGROUND: Sciatic nerve block when combined with femoral nerve block for total knee arthroplasty may provide superior analgesia but can produce footdrop, which may mask surgically induced peroneal nerve injury. In this prospective, randomized, observer-blinded study, we evaluated whether performing a selective tibial nerve block in the popliteal fossa would avoid complete peroneal motor block. METHODS: Eighty patients scheduled for primary total knee arthroplasty were randomized to receive either a tibial nerve block in the popliteal fossa or a sciatic nerve block proximal to its bifurcation in combination with femoral nerve block as part of a multimodal analgesia regimen. Local anesthetic solution of sufficient volume to encircle the target nerve was administered for the block, up to a maximum of 20 mL. General anesthesia was administered for surgery. After emergence from anesthesia, in the recovery room, the presence or absence of peroneal sensory and motor block was noted. Pain scores and opioid consumption were recorded for 24 hours after surgery. RESULTS: The tibial nerve block and sciatic nerve block were performed 1.7 cm (99% CI, 1.3 to 2.1) and 9.4 cm (99% CI, 8.3 to 10.5) proximal to the popliteal crease, respectively (99% CI for difference between means: 6.4 to 9.0; P < 0.001). A lower volume of ropivacaine 0.5% was used for the tibial nerve block, 8.7 mL (99% CI, 7.9 to 9.4) versus 15.2 mL (99% CI, 14.9 to 15.5), respectively (99% CI for difference between means, 5.6 to 7.3; P < 0.001). No patient receiving a tibial nerve block developed complete peroneal motor block compared to 82.5% of patients with sciatic nerve block (P < 0.001). There were no significant differences in the pain scores and opioid consumption between the groups. CONCLUSIONS: Tibial nerve block performed in the popliteal fossa in close proximity to the popliteal crease avoided complete peroneal motor block and provided similar postoperative analgesia compared to sciatic nerve block when combined with femoral nerve block for patients undergoing total knee arthroplasty.

Chitosan Nano/Microformulations for Antimicrobial Protection of Leather with a Potential Impact in Tanning Industry.

Tanned leather can be attacked by microorganisms. To ensure resistance to bacteria on leather surfaces, protection solutions need to be developed, addressing both environmental issues and economic viability. In this work, chitosan nano/microparticles (CNP) and chitosan/silver nano/microstructures (CSNP), containing silver nanoparticles around 17 nm size, were incorporated into leather, obtained from the industrial process. Low loads of chitosan-based nano/microformulations, 0.1% mass ratio, resulted in total bacteria reduction (100%) after 2 h towards Gram-positive Staphylococcus aureus, both with CNP and CSNP coatings. Otherwise, comparable tests with the Gram-negative bacteria, Klebsiella pneumoniae, Escherichia coli, showed no significant improvement under the coating acidic conditions. The antimicrobial activity was evaluated by standard test methods: (1) inhibition halo and (2) dynamic contact conditions. The developed protection of leather either with CNP or CSNP is much higher than the one obtained with a simple chitosan solution.

Inhibition of Escherichia Virus MS2, Surrogate of SARS-CoV-2, via Essential Oils-Loaded Electrospun Fibrous Mats: Increasing the Multifunctionality of Antivirus Protection Masks.

One of the most important measures implemented to reduce SARS-CoV-2 transmission has been the use of face masks. Yet, most mask options available in the market display a passive action against the virus, not actively compromising its viability. Here, we propose to overcome this limitation by incorporating antiviral essential oils (EOs) within polycaprolactone (PCL) electrospun fibrous mats to be used as intermediate layers in individual protection masks. Twenty EOs selected based on their antimicrobial nature were examined for the first time against the Escherichia coli MS2 virus (potential surrogate of SARS-CoV-2). The most effective were the lemongrass (LGO), Niaouli (NO) and eucalyptus (ELO) with a virucidal concentration (VC) of 356.0, 365.2 and 586.0 mg/mL, respectively. PCL was processed via electrospinning, generating uniform, beadless fibrous mats. EOs loading was accomplished via two ways: (1) physisorption on pre-existing mats (PCLaEOs), and (2) EOs blending with the polymer solution prior to fiber electrospinning (PCLbEOs). In both cases, 10% v/v VC was used as loading concentration, so the mats' stickiness and overwhelming smell could be prevented. The EOs presence and release from the mats were confirmed by UV-visible spectroscopy (≈5257-631 µg) and gas chromatography-mass spectrometry evaluations (average of ≈14.3% EOs release over 4 h), respectively. PCLbEOs mats were considered the more mechanically and thermally resilient, with LGO promoting the strongest bonds with PCL (PCLbLGO). On the other hand, PCLaNO and PCLaELO were deemed the least cohesive combinations. Mats modified with the EOs were all identified as superhydrophobic, capable of preventing droplet penetration. Air and water-vapor permeabilities were affected by the mats' porosity (PCL < PCLaEOs < PCLbEOs), exhibiting a similar tendency of increasing with the increase of porosity. Antimicrobial testing revealed the mats' ability to retain the virus (preventing infiltration) and to inhibit its action (log reduction averaging 1). The most effective combination against the MS2 viral particles was the PCLbLGO. These mats' scent was also regarded as the most pleasant during sensory evaluation. Overall, data demonstrated the potential of these EOs-loaded PCL fibrous mats to work as COVID-19 active barriers for individual protection masks.

Efficiency in Cow-Calf Systems With Different Ages of Cow Culling.

The bioeconomic efficiency of cow-calf systems was compared by a deterministic dynamic simulation. The simulation model considered stable cow-calf systems differentiated by the maximum age for culling cows, lifetime, culled at 4-13 years old. The necessary supply of metabolizable energy for the herd was established as natural grasslands, cultivated pasture in the winter/spring, and pre-dried pasture produced by the system. The biological efficiency of the systems was considered the ratio between the production of total live weight and the metabolizable energy consumed over one production cycle. Economic efficiency was determined by the ratio between gross margin and production area and the ratio between gross margin and number of cows. Bioeconomic efficiency was determined by a simple linear regression between biological efficiency, economic efficiency per area, and economic efficiency per cow. The efficiency of the animal unit, considering biological efficiency and economic efficiency per area were better in the system that culled cows at 4 years old, while economic efficiency per cow was better in the system that culled cows at 13 years old. In determining the bioeconomic efficiency of the systems, the best results were found in the system that culled cows at 6 years old, which suggests that the best efficiency of a cow-calf herd is reached when the adult age and mature weight of the cow are reached, and there is no more energy used for growing. The results indicate that stable cow-calf herds express their best biological efficiency and economic efficiency per area when the cow culling age is lower. However, economic efficiency per cow depends on cows that remain in the herd as long as possible. The culling age of cow that balances these biological and economic indicators is reached around 5 and half years.

Fibra dietética e gordura saturada: relação entre marcadores bioquímicos da síndrome metabólica / Dietary fiber and saturated fat: relation between biochemical markers of metabolic syndrome

Aims: To relate the consumption of dietary fiber and saturated fat to biochemical markers in individuals with metabolic syndrome.Methods: The database of this cross-sectional study consisted of both male and female adults diagnosed with metabolic syndrome, according to the National Cholesterol Education Program's Adult Treatment Panel III, who participated in a study at the Pontifical Catholic University of Rio Grande do Sul. Data on all individuals registered at baseline who had complete information about their food intake were used. Consumption of dietary fiber and saturated fat was calculated based on the information provided by a 24-hour recall survey and a two-day food record. We evaluated the subjects in general and stratified by gender. The data were analyzed using descriptive statistics and the Student's t test. The correlation between fiber and saturated fat intake and biochemical markers was measured by Pearson's correlation coefficient. The significance level was set at 5%.Results: There were 79 individuals whose records contained complete information and who were eventually included in the study. A significant positive correlation was observed between saturated fat intake and serum triglyceride levels (r=0.30; p=0.008) and between saturated fat intake and insulin (r=0.26; p=0.021). Also, a significant inverse correlation was observed between fiber intake and serum levels of HDL cholesterol (r=-0.28; p=0.011). When stratified by gender, the positive correlation between consumption of saturated fat and triglycerides remained significant only among men (r=0.44; p=0.034).Conclusions: In this population diagnosed with metabolic syndrome, lower levels of HDL cholesterol were found in individuals who referred higher intake of dietary fiber, while individuals who reported elevated consumption of saturated fat had higher levels of insulin and triglycerides. In the gender-stratified analysis, positive correlation was found only between saturated fat consumption and serum triglyceride levels in men.

Objetivos: Relacionar o consumo de fibra alimentar e de gordura saturada com marcadores bioquímicos em indivíduos portadores de síndrome metabólica.Métodos: A base de dados deste estudo transversal foi formada por adultos de ambos os sexos com diagnóstico de síndrome metabólica conforme o National Cholesterol Education Program's Adult Treatment Panel III, participantes de um estudo realizado na Pontifícia Universidade Católica do Rio Grande do Sul. Foram utilizados os dados de todos os indivíduos cadastrados na linha de base que possuíam informações completas sobre o consumo alimentar. O consumo de fibra alimentar e de gordura saturada foi apurado a partir das informações obtidas de um recordatório alimentar 24 horas e de um registro alimentar de dois dias. Foram avaliados os sujeitos de forma geral e estratificados por sexo. A análise de dados foi realizada por estatística descritiva e teste t de Student. A correlação entre o consumo de fibras e de gordura saturada com marcadores bioquímicos foi obtida através do coeficiente de correlação de Pearson. Foi utilizado nível de significância de 5%.Resultados: Foram encontrados 79 indivíduos cujos registros continham as informações completas, sendo incluídos no estudo. Observou-se correlação positiva significativa do consumo de gordura saturada com níveis séricos de triglicerídeos (r=0,30; p=0,008) e com insulina (r=0,26; p=0,021). Além disso, observou-se correlação inversa significativa entre consumo de fibras e níveis séricos de HDL-colesterol (r=-0,28; p=0,011). Quando estratificados os indivíduos por sexo, observou-se que a correlação positiva entre consumo de gordura saturada e nível de triglicerídeos manteve-se significativa apenas entre os homens (r=0,44; p=0,034).Conclusões: Nessa população com diagnóstico de síndrome metabólica, foram encontrados níveis mais baixos de HDL-colesterol nos indivíduos que referiam maior consumo de fibra alimentar, enquanto os indivíduos que relataram elevado consumo de gordura saturada tiveram níveis mais altos de insulina e de triglicerídeos. Na análise estratificada por sexo, correlação positiva foi encontrada apenas entre consumo de gordura saturada e níveis séricos de triglicerídeos em homens.