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1.
Medicina (Kaunas) ; 60(2)2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38399610

RESUMEN

Background and Objectives: The negative effects of smoking on the musculoskeletal system were presented by many authors, although the relationship between smoking and osteoarthritis remains unclear. The aim of this paper was to investigate the negative effects of smoking on meniscal tissue in osteoarthritic knees by microscopic examination, by adapting the Bonar scoring system and its modifications. Materials and Methods: The study involved 34 patients with varus knees, from whom 65 samples of knee menisci were obtained. The mean age in the studied group was 65.385 years. The smoking status of the patients concluded that there were 13 smokers and 21 nonsmokers. Results: Among smokers, the mean classical Bonar score was 8.42 and the mean modified Bonar score was 6.65, while nonsmokers were characterized by scores of 8.51 and 7.35, respectively. There was a statistically significant negative correlation between the number of cigarettes and the collagen in the medial meniscus (p = 0.0197). Moreover, in the medial meniscus, the modified Bonar score correlated negatively with the number of cigarettes (p = 0.0180). Similarly, such a correlation was observed between the number of cigarettes and the modified Bonar score in the lateral meniscus (p = 0.04571). Furthermore, no correlation was identified between the number of cigarettes and the classical Bonar score in the lateral meniscus. There was a statistically significant difference in the collagen variable value between the smokers and nonsmokers groups (p = 0.04525). Conclusions: The microscopic investigation showed no differences in the menisci of smokers and nonsmokers, except for the collagen, which was more organized in smokers. Moreover, the modified Bonar score was correlated negatively with the number of cigarettes, which supports the role of neovascularization in meniscus pathology under the influence of tobacco smoking.


Asunto(s)
Fumar Cigarrillos , Menisco , Humanos , Anciano , Proyectos Piloto , Fumar Cigarrillos/efectos adversos , Fumar/efectos adversos , Colágeno , Imagen por Resonancia Magnética
2.
Sensors (Basel) ; 23(6)2023 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-36991821

RESUMEN

In this paper, we present our investigation of the 2D Hand Gesture Recognition (HGR) which may be suitable for the control of the Automated Guided Vehicle (AGV). In real conditions, we deal with, among others, a complex background, changing lighting conditions, and different distances of the operator from the AGV. For this reason, in the article, we describe the database of 2D images created during the research. We tested classic algorithms and modified them by us ResNet50 and MobileNetV2 which were retrained partially using the transfer learning approach, as well as proposed a simple and effective Convolutional Neural Network (CNN). As part of our work, we used a closed engineering environment for rapid prototyping of vision algorithms, i.e., Adaptive Vision Studio (AVS), currently Zebra Aurora Vision, as well as an open Python programming environment. In addition, we shortly discuss the results of preliminary work on 3D HGR, which seems to be very promising for future work. The results show that, in our case, from the point of view of implementing the gesture recognition methods in AGVs, better results may be expected for RGB images than grayscale ones. Also using 3D imaging and a depth map may give better results.


Asunto(s)
Gestos , Redes Neurales de la Computación , Algoritmos , Extremidad Superior , Aprendizaje , Mano
3.
Molecules ; 28(6)2023 Mar 13.
Artículo en Inglés | MEDLINE | ID: mdl-36985556

RESUMEN

Triterpenoids are a group of secondary plant metabolites, with a remarkable pharmacological potential, occurring in the cuticular waxes of the aerial parts of plants. The aim of this study was to analyze triterpenoid variability in the fruits and leaves of three apple cultivars during the growing season and gain new insights into their health-promoting properties and fate during juice and purée production. The identification and quantification of the compounds of interest were conducted using gas chromatography coupled with mass spectrometry. The waxes of both matrices contained similar analytes; however, their quantitative patterns varied: triterpenic acids prevailed in the fruits, while higher contents of steroids and esterified forms were observed in the leaves. The total triterpenoid content per unit area was stable during the growing season; the percentage of esters increased in the later phases of growth. Antioxidative and anti-inflammatory properties were evaluated with a series of in vitro assays. Triterpenoids were found to be the main anti-inflammatory compounds in the apples, while their impact on antioxidant capacity was minor. The apples were processed on a lab scale to obtain juices and purées. The apple purée and cloudy juice contained only some of the triterpenoids present in the raw fruit, while the clear juices were virtually free of those lipophilic compounds.


Asunto(s)
Malus , Triterpenos , Malus/química , Antioxidantes/análisis , Triterpenos/química , Cromatografía de Gases y Espectrometría de Masas , Frutas/química , Ceras/química
4.
Chemistry ; 28(41): e202200399, 2022 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-35522013

RESUMEN

Group 9 metals, in particular RhIII complexes with cyclopentadienyl ligands, are competent C-H activation catalysts. Recently, a Cp*RhIII -catalyzed reaction of alkenes with N-enoxyphthalimides showed divergent outcome based on the solvent, with carboamination favored in methanol and cyclopropanation in 2,2,2-trifluoroethanol (TFE). Here, we create selectivity and activity maps capable of unravelling the catalyst-solvent interplay on the outcome of these competing reactions by analyzing 42 cyclopentadienyl metal catalysts, CpX MIII (M=Co, Rh, Ir). These maps not only can be used to rationalize previously reported experimental results, but also capably predict the behavior of untested catalyst/solvent combinations as well as aid in identifying experimental protocols that simultaneously optimize both catalytic activity and selectivity (solutions in the Pareto front). In this regard, we demonstrate how and why the experimentally employed Cp*RhIII catalyst represents an ideal choice to invoke a solvent-induced change in reactivity. Additionally, the maps reveal the degree to which even perceived minor changes in the solvent (e. g., replacing methanol with ethanol) influence the ratio of carboamination and cyclopropanation products. Overall, the selectivity and activity maps presented here provide a generalizable tool to create global pictures of anticipated reaction outcome that can be used to develop new experimental protocols spanning metal, ligand, and solvent space.


Asunto(s)
Rodio , Catálisis , Ligandos , Metanol , Solventes , Estereoisomerismo
5.
Chem Rev ; 120(18): 10516-10543, 2020 09 23.
Artículo en Inglés | MEDLINE | ID: mdl-32897713

RESUMEN

The development of catalytic enantioselective transformations, enabling the construction of complex molecular scaffolds from simple precursors, has been a long-standing challenge in organic synthesis. Recent achievements in transition-metal catalyzed enantioselective functionalizations of carbon-hydrogen (C-H) bonds represent a promising pathway toward this goal. Over the last two decades, iridium catalysis has evolved as a valuable tool enabling the stereocontrolled synthesis of chiral molecules via C-H activation. The development of iridium-based systems with various chiral ligand classes, as well as studies of their reaction mechanisms, has resulted in dynamic progress in this area. This review aims to present a comprehensive picture of the enantioselective functionalizations of C-H bonds by chiral iridium complexes with emphasis on the mechanisms of the C-H activation step.

6.
Molecules ; 27(3)2022 Feb 02.
Artículo en Inglés | MEDLINE | ID: mdl-35164290

RESUMEN

Picking vegetables is, along with salting and drying, one of the oldest ways to preserve food in the world. This is the process of decomposition of simple sugars into lactic acid with the participation of lactic bacteria. The aim of the study was to obtain powders from fermented red beet juice with the highest possible amount of lactic acid bacteria (LAB) and active ingredients. For the analysis, juices were squeezed from the vegetables and two types of fermentation were used: a spontaneous fermentation and a dedicated one. After inoculation, samples were taken for analysis on a daily basis. Extract, pH, total acidity, pigments, and color were measured. In addition, microbiological tests were also carried out. The juices from the fifth day of fermentation was also spray dried, to obtain fermented beetroot powder. Juices from 3-5th day were characterized by a high content of LAB and betanin, had also a low pH, which proves that the lactic fermentation is working properly. The exception was the juice from spontaneous fermentation. According to the observations, the fermentation process did not run properly, and further analysis is needed. The powders were stable; however, results obtained from the pigment content and the LAB content are not satisfactory and require further analysis.

7.
Molecules ; 27(23)2022 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-36500730

RESUMEN

Red, yellow, and green peppers are vegetables rich in natural pigments. However, they belong to seasonal vegetables and need to be treated to prolong their shelf life. One new approach to processing vegetables is to pickle them using lactic acid bacteria. The use of such a process creates a new product with high health value, thanks to the active ingredients and lactic acid bacteria. Therefore, this study aimed to evaluate the effect of the applied strain of lactic acid bacteria (LAB) on the chemical properties, including the content of active compounds (pigments) and the physical properties of the peppers. Levilactobacillus brevis, Limosilactobacillus fermentum, and Lactoplantibacillus plantarum were used for fermentation and spontaneous fermentation. The pigments, polyphenols content, and antioxidant properties were determined in the pickled peppers, as well as sugar content, color, dry matter, texture properties, and the count of lactic acid bacteria. In all samples, similar growth of LAB was observed. Significant degradation of chlorophylls into pheophytins was observed after the fermentation process. No significant differences were observed in the parameters tested, depending on the addition of dedicated LAB strains. After the fermentation process, the vitamin C and total polyphenols content is what influenced the antioxidant activity of the samples. It can be stated that the fermentation process changed the red bell pepper samples in the smallest way and the green ones in the highest way.


Asunto(s)
Capsicum , Lactobacillales , Limosilactobacillus fermentum , Ácido Láctico/metabolismo , Fermentación , Antioxidantes/química , Capsicum/química , Polifenoles/análisis , Verduras/metabolismo , Lactobacillales/metabolismo
8.
Angew Chem Int Ed Engl ; 61(30): e202202306, 2022 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-35419901

RESUMEN

1,3,2-diazaphospholenes hydrides (DAP-Hs) are highly nucleophilic organic hydrides serving as main-group catalysts for a range of attractive transformations. DAP hydrides can act as stoichiometric hydrogen atom transfer agents in radical reactions. Herein, we report a DAP-catalyzed reductive radical cyclization of a broad range of aryl and alkyl halides under mild conditions. The pivotal DAP catalyst turnover was achieved by a DBU-assisted σ-bond metathesis between the formed DAP halide and HBpin, which rapidly regenerates DAP-H. The transformation is significantly accelerated by irradiation with visible light. Mechanistic investigations indicate that visible light irradiation leads to the formation of DAP dimers, which are in equilibrium with DAP radicals and accelerate the cyclization. The direct use of (DAP)2 enabled a catalytic protocol in the absence of light.

9.
Clin Orthop Relat Res ; 479(8): 1830-1838, 2021 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-33930002

RESUMEN

BACKGROUND: Cam morphology is thought to originate near puberty and reflects a response of the peripheral aspect of the proximal femoral physis to increased local load. Participation in particular sports activities has been associated with cam morphology in contemporary patient populations; however, it is unclear whether cam is a recent phenomenon. There are limited data regarding the frequency of its occurrence and the general deviations in femoral anatomy in different historical populations. Such information may help to understand the possible influence of lifestyle and diet on cam morphology. QUESTIONS/PURPOSES: The purpose of this study was to evaluate femoral morphology in three historical populations. We asked: (1) Was cam morphology present in the three study populations, did those populations differ, and were there differences between sexes? (2) Were there differences in neck-shaft angle, version, or inclination between and among the examined populations? METHODS: We examined 204 adult femurs from the Neolithic population from Iran (n = 37, 3000 BC to 1631 BC), medieval population from Poland (n = 135, 10th to 13th centuries), and contemporary Australian aborigines (n = 32, early 20th century), provided by the Open Research Scan Archive, Museum of the First Piasts at Lednica and the University of Wroclaw, respectively. All three human populations represent different chronologic periods and lifestyles. All bones were scanned using CT and then measured on their three-dimensional (3-D) reconstructions in selected planes. Cam impingement was defined as an alpha angle > 55° measured on the inclination view. To evaluate the differences in anatomy between populations, we measured the true neck-shaft angle on the true AP view, apparent neck-shaft angle on the apparent AP view, the version angle on the version view, and the inclination angle on the inclination view. The prevalence of cam morphology and other anatomic parameters were compared among groups using chi-square test, one-way ANOVA with post hoc Tukey test, and paired t-test. RESULTS: Cam morphology was present in 5% of the Neolithic population from Iran, in 7% of the medieval population from Poland, and 3% of the contemporary Australian aborigine femurs (OR Neolithic population from Iran/the medieval population from Poland 0.7 [95% CI 0.2 to 3.4]; p = 0.67; OR Neolithic population from Iran/contemporary Australian aborigines 1.8 [95% CI 0.2 to 20.5]; p = 0.65; OR the medieval population from Poland/contemporary Australian aborigines 2.5 [95% CI 0.3 to 20.1]; p = 0.40). There were differences in the presence of cam morphology between the sexes in the medieval population from Poland with both femurs (females: 1% [1 of 76]; males: 15% [9 of 59]; p = 0.002). There was a difference in true neck-shaft angle between the Neolithic population from Iran (121° ± 6°) and contemporary Australian aborigines (131° ± 5°; mean difference 10° [95% CI 7° to 13°]; p < 0.001) and between the medieval population from Poland (124° ± 5°) and the contemporary Australian aborigines (mean difference 7° [95% CI 5° to 9°]; p < 0.001). Apparent neck-shaft angle differed between the Neolithic population from Iran (126° ± 6°) and the contemporary Australian aborigines (134° ± 5°; mean difference 8° [95% CI 6° to 11°]; p < 0.001), and between the medieval population from Poland (126° ± 6°) and the contemporary Australian aborigines (mean difference 9° [95% CI 7° to 11°]; p < 0.001). Moreover, we observed a difference in the version angle between the Neolithic population from Iran (19° ± 7°) and the medieval population from Poland (12° ± 9°; mean difference 7° [95% CI 4° to 10°]; p < 0.001] and in the inclination angle between aforementioned groups (18° ± 7° versus 11° ± 8°; mean difference 7° [95% CI 5° to 10°]; p < 0.001). CONCLUSION: This study found that cam morphology existed in historical populations at rates comparable with a contemporary population. CLINICAL RELEVANCE: The presence of cam morphology in historical populations suggests that cam morphology can develop outside of the intense sports activity seen in modern adolescents. Further study will help elucidate the etiology of cam morphology, which may be useful in the development of preventive strategies.


Asunto(s)
Enfermedades del Desarrollo Óseo/epidemiología , Enfermedades del Desarrollo Óseo/historia , Cuello Femoral/patología , Fémur/patología , Nativos de Hawái y Otras Islas del Pacífico/historia , Adulto , Australia/epidemiología , Australia/etnología , Enfermedades del Desarrollo Óseo/etnología , Femenino , Historia del Siglo XX , Historia Antigua , Historia Medieval , Humanos , Incidencia , Irán/epidemiología , Irán/etnología , Masculino , Polonia/epidemiología , Polonia/etnología
10.
J Pediatr Orthop ; 41(4): e347-e352, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-33560710

RESUMEN

BACKGROUND: Although Fassier-Duval (FD) rods have been used for almost 2 decades, knowledge of factors predisposing to their failure is limited. Thus, the purpose of this study was to: (1) present the most common complications of FD rodding, (2) present tips on how to avoid or overcome them, and (3) identify factors predisposing to treatment failure. METHODS: Fifty-eight rod segments in 19 patients with osteogenesis imperfecta (mainly type III) underwent analysis with a median follow-up (FU) time of 4.4 years. We assessed the total number of complications clinically and radiographically. Next, the possible predisposing factors leading to failure were assessed using the Mann-Whitney U test. In addition, we evaluated the cutoff age for the increased rate of complications using the Youden index. A P<0.05 was considered significant. RESULTS: The total number of complications reached 44.8%. The most common complications included: migration of the male or female implant (45.7% and 25.7% out of the total number of complications, respectively), bone fracture with bending of the rod (8.6%), and rotational deformities (8.6%). Significant differences in patients' ages at the time of surgery were found between the group with and without complications (P=0.04), while sex, segment treated, preceding surgeries, length of FU, FD rod diameter, and length of bisphosphonate treatment were not significant. The Youden index showed that the risk of complications rose significantly in patients treated when younger than 5.5 years of age (P<0.05). CONCLUSIONS: This series displays the effectiveness and utility of FD rods at a median FU of over 4 years. Complication rates were comparable with the existing literature, with a notable increase in the number of side effects observed in younger patients (below the age of 5). LEVEL OF EVIDENCE: Level IV-therapeutic study.


Asunto(s)
Fracturas Óseas/etiología , Fijadores Internos/efectos adversos , Osteogénesis Imperfecta/cirugía , Prótesis e Implantes/efectos adversos , Falla de Prótesis/etiología , Adolescente , Niño , Preescolar , Femenino , Estudios de Seguimiento , Humanos , Masculino , Osteogénesis Imperfecta/complicaciones , Osteogénesis Imperfecta/diagnóstico por imagen , Complicaciones Posoperatorias/diagnóstico por imagen , Complicaciones Posoperatorias/etiología , Estudios Retrospectivos , Insuficiencia del Tratamiento
11.
Angew Chem Int Ed Engl ; 60(34): 18532-18536, 2021 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-34153163

RESUMEN

Atropo-enantioselective biaryl coupling through C-H bond functionalization is an emerging technology allowing direct construction of axially chiral molecules. This approach is largely limited to electrophilic coupling partners. We report a highly atropo-enantioselective C-H arylation of tetralone derivatives paired with aryl boronic esters as nucleophilic components. The transformation is catalyzed by chiral cyclopentadienyl (Cpx ) iridium(III) complexes and enabled by oxidatively enhanced reductive elimination from high-valent cyclometalated Ir-species.

12.
Angew Chem Int Ed Engl ; 60(2): 655-659, 2021 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-32986927

RESUMEN

High-valent cyclopentadienyl cobalt catalysis is a versatile tool for sustainable C-H bond functionalizations. To harness the full potential of this strategy, control of the stereoselectivity of these processes is necessary. Herein, we report highly enantioselective intermolecular carboaminations of alkenes through C-H activation of N-phenoxyamides catalyzed by CoIII -complexes equipped with chiral cyclopentadienyl (Cpx ) ligands. The method converts widely available acrylates as well as bicyclic olefins into attractive enantioenriched isotyrosine derivatives as well as elaborated amino-substituted bicyclic scaffolds under very mild conditions. The outlined reactivity is unique to the Cpx CoIII complexes and is complementary to the reactivity of 4d- and 5d- precious-metal catalysts.

13.
BMC Musculoskelet Disord ; 21(1): 475, 2020 Jul 21.
Artículo en Inglés | MEDLINE | ID: mdl-32693786

RESUMEN

BACKGROUND: Three-dimensional idiopathic scoliosis cannot be accurately assessed with the aid of a single plane parameter - the Cobb angle. We propose a novel method for evaluating the three-dimensional (3D) pattern of scoliosis based on two X-rays (PA and lateral). The proposed method consists of the measurements of the angles between the upper endplate of the upper-end vertebra and the lower endplate of the lower-end vertebra (3D scoliosis angle). METHODS: The 3D-angles of thirty scoliosis curves were measured with either computed tomography (CT) or digitally reconstructed radiographs (DRRs): PA and lateral. CT was used as a reference. In the case of CT, the 3D angle was calculated based on the coordinates of three points situated on the upper endplate and those of three points situated on the lower endplate of the scoliosis curve. In the case of the DRR, the 3D angle was calculated using the four-angle method: the angles formed by the endplates of the curve with the transverse plane. The results were tested with the Student's t-test, and the agreement of measurements was tested with the intraclass correlation coefficient. RESULTS: There was no significant difference between the 3D-angle measurements obtained with DRRs versus CT, p > 0.05. There was, however, a significant difference between the 3D-scoliosis angle and the Cobb angle measurements performed based on the X-rays. The reproducibility and reliability of 3D angle measurements were high. CONCLUSIONS: Based on two standard radiographs, PA and lateral, it is possible to calculate the 3D scoliosis angle. The proposed method facilitates 3D-scoliosis assessment without the use of sophisticated devices. Considering the 3D nature of AIS, the 3D parameters of the spine may help to apply a more effective treatment and estimate a more precise prognosis for patient with scoliosis.


Asunto(s)
Escoliosis , Humanos , Imagenología Tridimensional , Radiografía , Reproducibilidad de los Resultados , Escoliosis/diagnóstico por imagen , Columna Vertebral , Tomografía Computarizada por Rayos X
14.
Molecules ; 25(17)2020 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-32825691

RESUMEN

Furocoumarins are a group of plant phytoalexins exhibiting various bioactive properties; the most important of which are photosensitization and alteration of P450 cytochrome activity. Supercritical fluid extraction with carbon dioxide has been proposed as a green alternative for an organic solvent extraction of the furocoumarins. Four plant matrices rich in furocoumarins were extracted with CO2 at a temperature of 80 °C and pressure of 40 MPa, as these conditions were characterized by the highest solubility of furocoumarins. The extracts collected were analyzed using the HPLC method and the results obtained were used for the mathematical modeling of the observed phenomena. The total content of the furocoumarins in the matrices was 4.03-26.45 mg g-1 of dry weight. The impact of the process parameters on the solubility was consistent with the Chrastil equation. The broken plus intact cell model proved to be suitable to describe extraction curves obtained. The research proved the possibility of supercritical carbon dioxide utilization for the extraction of the furocoumarins from plant material and provided valuable data for prospective industrial-scale experiments.


Asunto(s)
Dióxido de Carbono/química , Cromatografía con Fluido Supercrítico/métodos , Furocumarinas/análisis , Furocumarinas/aislamiento & purificación , Fármacos Fotosensibilizantes/análisis , Fármacos Fotosensibilizantes/aislamiento & purificación , Plantas/química , Fenómenos Fisiológicos Celulares , Furocumarinas/química , Cinética , Fármacos Fotosensibilizantes/química , Plantas/clasificación
15.
Molecules ; 23(7)2018 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-30011916

RESUMEN

The scope of ruthenium (Ru)-catalyzed cross metathesis (CM) of allyl-decorated polyhedral oligomeric silsesquioxanes (POSS) was explored. A variety of different commercial and non-commercial ruthenium complexes were tested to determine that the nitro-activated Ru catalyst is optimal for this transformation. The reported transformation was used to prepare selected hybrid steroid-POSS compounds.


Asunto(s)
Compuestos de Organosilicio/química , Compuestos de Organosilicio/síntesis química , Rutenio/química , Catálisis
16.
Molecules ; 23(11)2018 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-30373258

RESUMEN

Apple pomace, a byproduct of juice production, is a rich source of bioactive compounds and nutrients. Supercritical fluid extraction was proposed as a method for a fast and selective extraction of hydrophobic compounds with a pharmaceutical potential from this matrix. Chromatographic analysis showed that the pomace contained significant amounts of such substances, the most abundant of them were ursolic acid, oleanolic acid, and ß-sitosterol. The solubility was chosen as a primary factor for a selection of the extraction conditions; the best results were acquired for a temperature of 80 °C and a pressure of 30 MPa. The equation proposed by Chrastil was applied for the description of the impact of the process parameters on the solubility of the analytes; the obtained values of coefficients of determination were satisfactory, despite the fact that the equation was developed for binary systems. The extraction curves obtained during the experiments were used for the description of the process kinetics using the Broken plus Intact Cell model. The impact of the temperature, pressure, and flow rate of carbon dioxide on the mass transfer phenomena was investigated. The data obtained allowed the prediction of the extraction curve for the process conducted on the larger scale.


Asunto(s)
Dióxido de Carbono , Cromatografía con Fluido Supercrítico , Malus/química , Fitosteroles/química , Extractos Vegetales/química , Triterpenos/química , Dióxido de Carbono/química , Cromatografía de Gases , Cromatografía con Fluido Supercrítico/métodos , Modelos Teóricos , Solventes
17.
Angew Chem Int Ed Engl ; 57(4): 1068-1072, 2018 01 22.
Artículo en Inglés | MEDLINE | ID: mdl-29205718

RESUMEN

Reported herein is a photochemical cascade process that combines the excited-state and ground-state reactivity of chiral organocatalytic intermediates. This strategy directly converts racemic cyclopropanols and α,ß-unsaturated aldehydes into stereochemically dense cyclopentanols with exquisite stereoselectivity. Mechanistic investigations have enabled elucidating the origin of the stereoconvergence, which is governed by a kinetic resolution process.

18.
Angew Chem Int Ed Engl ; 57(39): 12901-12905, 2018 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-30044513

RESUMEN

An enantioselective C-H arylation of phosphine oxides with o-quinone diazides catalyzed by an iridium(III) complex bearing an atropchiral cyclopentadienyl (Cpx ) ligand and phthaloyl tert-leucine as co-catalyst is reported. The method allows access to a) P-chiral biaryl phosphine oxides, b) atropo-enantioselective construction of sterically demanding biaryl backbones, and also c) selective assembly of axial and P-chiral compounds in excellent yields and diastereo- and enantioselectivities. Enantiospecific reductions provide monodentate chiral phosphorus(III) compounds having structures and biaryl backbones with proven importance as ligands in asymmetric catalysis.

19.
Int J Mol Sci ; 18(2)2017 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-28134807

RESUMEN

Anthocyanins are a group of phenolic compounds responsible for red, blue and violet colouration of many fruits, vegetables and flowers. The high content of these pigments is important as it influences directly their health promoting properties as well as the sensory quality of the product; however they are prone to degradation by, inter alia, elevated temperature and tissue enzymes. The traditional thermal methods of food preservation cause significant losses of these pigments. Thus, novel non-thermal techniques such as high pressure processing, high pressure carbon dioxide and high pressure homogenization are under consideration. In this review, the authors attempted to summarize the current knowledge of the impact of high pressure techniques on the stability of anthocyanins during processing and storage of fruit and vegetable products. Furthermore, the effect of the activity of enzymes involved in the degradation of these compounds has been described. The conclusions including comparisons of pressure-based methods with high temperature preservation techniques were presented.


Asunto(s)
Antocianinas/química , Frutas/química , Presión , Verduras/química , Enzimas/metabolismo , Temperatura
20.
Pol J Microbiol ; 66(1): 67-74, 2017 Mar 30.
Artículo en Inglés | MEDLINE | ID: mdl-29359691

RESUMEN

The presence of Alicyclobacillus, a thermoacidophilic and spore-forming bacterium, in acidic fruit juices poses a serious problem for the processing industry. A typical sign of spoilage in contaminated juices is a characteristic phenolic off-flavour associated with the production of guaiacol. Spores are formed in response to starvation and in a natural environment re-access the nutrients, e.g.: L-alanine and AGFK - a mixture of asparagine, glucose, fructose and potassium, triggers germination. The aim of this study was to estimate the impact of L-alanine and AGFK on the germination of the spores of two Alicyclobacillus acidoterrestris strains and to evaluate the relationship of the germination rate with dipicolinic acid (DPA) release. The spores were suspended in apple juice or in buffers at pH 4 and pH 7, followed by the addition of L-alanine and AGFK. Suspensions were or were not subjected, to a temperature of 80°C/10 min and incubated for various periods of time at 45°C. Optical density (OD660) was used to estimate the number of germinated spores. The amount of DPA released was determined using HPLC. The results indicate that the degree of germination of A. acidoterrestris spores depended on the strain and time of incubation and the nutritious compounds used. The data obtained show that the amount of DPA released correlated to the number of A. acidoterrestris spores germinated.


Asunto(s)
Alicyclobacillus/fisiología , Ácidos Picolínicos/metabolismo , Esporas Bacterianas/fisiología , Alicyclobacillus/clasificación , Alicyclobacillus/efectos de los fármacos , Técnicas Bacteriológicas , Medios de Cultivo/química , Jugos de Frutas y Vegetales , Malus , Purinas , Factores de Tiempo
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