248 research outputs found

    Construction of Chemoenzymatic Linear Cascades for the Synthesis of Chiral Compounds

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    Inspired by nature, synthetic chemists try to mimic the efficient metabolic networks in living organisms to build complex molecules by combining different types of catalysts in the same reaction vessel. These multistep cascade processes provide many advantages to synthetic procedures, resulting in higher productivities with lower waste generation and cost. However, combining different chemo- and biocatalysts can be challenging as reaction conditions might differ greatly. As a highly multidisciplinary field that benefits from advances in chemical catalysis, molecular biology and reaction engineering, this area of study is rapidly progressing. In this Review, we highlight recent trends and advances in the construction of multistep chemoenzymatic one-pot cascades to access chiral compounds as well as the different strategies to solve current challenges in the field

    Effects of a fire on runoff and erosion on mediterranean forest soils in SE Spain

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    From 1985 to 1990, precipitation, runoff and soil erosion have been studied on experimental plots in a locality of Alicante (SE Spain). A prescribed burning was carried out in September of 1989, (maximum temperature was moderate). In order to know soil evolution, soil was sampled three times: before fire, one day after fire and six months later. One day after fire, a significant increase in organic matter content, total nitrogen, available phosphorus and the cations: K+, Mg2+ and N+, was found. On the other hand, Ca2+ and C.E.C. showed an opposite pattern. The modified values after fire tended to go bacic to the initial levels in the case of organic matter, phosphorus, Na+, Ca2+ and C.E.C. Annual runoff after fire is significantly lower than in the year before fire, whilst average runoff in the year after fire is only significantly different when the most erosive year (October 1987-September 1988) is not considered. The runoff decrease will be related with a lower average precipitation after fire. There are no significant differences in the sediment yield between the year before and after the fire. The nutrient outputs and runoff decrease is greater than the nutrient inputs and precipitation decrease after fire. Nutrient output in runoff after fire ranges between 8 to 35 % of the previous year, whilst volume of runoff is only 3 %, implying a greater concentration.[es] Se han estudiado los flujos de escorrentía y remoción de suelo, así como su composición química durante cinco años (1985-1990) en unas parcelas de erosión en una localidad de la provincia de Alicante (SE-España). En septiembre de 1989 se incendió la vegetación de las parcelas registrándose temperaturas moderadas. Se ha realizado un seguimiento de la química del suelo mediante tres muestreos: previo al fuego, al día siguiente y 180 días después. Al día siguiente del incendio se ha producido en el suelo un incremento estadísticamente significativo del contenido en materia orgánica, nitrógeno total, fósforo asimilable y los cationes cambiables: K+, Mg2+ y N+. Por el contrario, hay una disminución de Ca2+ y de la C.I.C. Los valores modificados tras el incendio tienden a recuperar su nivel Inicial en el caso de materia orgánica, fósforo. Na+, Ca2+ y C.I.C. La escorrentía anual tras el incendio es significativamente menor que la del año anterior al incendio, mientras que la escorrentía media es significativamente menor sólo en el caso de no considerar el año más erosivo (Octubre 1987-Septiembre 1988), lo que estaría asociado con una disminución de la precipitación media tras el incendio. Por su parte, la producción de sedimentos del año posterior al incendio no presenta diferencias significativas respecto al año anterior. La disminución en la salida de nutrientes y en el volumen de escorrentía es más acentuada que la disminución en la entrada de nutrientes y en el volumen de la precipitación después del incendio. La salida de nutrientes por escorrentía tras el incendio presenta un rango entre 8 y 35% del año anterior, cuando el volumen sólo representa el 3 %, lo que Implica un aumento en su concentración. [fr] On a étudié les flux de ruissellement et de transport du sol, ainsi que sa composition chimique, pendant cinq ans (1985-1990), dans des parcelles d'érosion dans une localité de la Province d'Alicante (SE-Espagne). En septembre 1989, on a brûle la végétation des parcelles, en enregistrant des températures modérées. On a réalisé un suivi de la chimie du sol par trois échantillonnages: avant le feu, le jour suivant et 180 jours plus tard. Le jour après l'incendie, il s'est produit dans le sol une augmentation statistiquement significative de la teneur en matière organique, azote total, phosphore assimilable, et des cations changeables: K+ Mg2+ et Na+. Au contraire, il y a une diminution de Ca2+ et de la C.I.C. Les valeurs modifiées après l'incendie tendent à reprendre leur niveau initial dans le cas de la matière organique, phosphore, Na+ Ca2+ et C.I.C. Le ruissellement annuel après l'incendie est significativement moindre que pour l'année avant l'incendie, cependant que le ruissellement moyen est significativement plus faible uniquement dans le cas où l'on ne considère pas l'année où l'érosion a été maximale (octobre 1987-septembre 1988), ce qui serait associé à une diminution de la précipitation moyenne après l'incendie. D'autre part, la production de sédiments pendant l'année postérieure à l'incendie ne présente pas de différences significatives par rapport à l'année précédente. La diminution de l'exportation d'éléments nutritifs et du volume de ruissellement est plus accentuée que la diminution de l'entrée d'éléments nutritifs et que le volume de la précipitation après l'incendie. L'exportation d'éléments nutritifs par ruissellement après l'incendie reste dans une gamme de 8 à 35% par rapport à l'année précédente, tandis que le volume ne représente que 3%, ce qui implique une augmentation de la concentration

    Risk factors for metachronous colorectal cancer or advanced lesions after endoscopic resection of serrated polyps: a systematic review and meta-analysis

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    \ua9 2024 American Society for Gastrointestinal Endoscopy. Background and Aims: Serrated polyps (SPs) are precursors to 15% to 20% of colorectal cancers (CRCs). However, there are uncertainties regarding which SPs require surveillance and at what intervals, with recommendations adapted from those for adenomas in the absence of solid evidence. Our aim was to assess which SP risk characteristics relate to a higher risk of metachronous CRC or advanced polyps. Methods: We systematically searched PubMed, Embase, and Cochrane for cohort studies, case-control studies, and clinical trials from inception to December 31, 2023, of CRC or advanced polyps (advanced adenoma [AA] or advanced SP) incidence at surveillance stratified by baseline SP size, dysplasia, location, and multiplicity. We defined advanced SPs as those ≥10 mm or with dysplasia. CRC and advanced polyp incidence per 1000 person-years were estimated. We performed a meta-analysis by calculating pooled relative risks (RRs) using a random-effects model. Results: A total of 5903 studies were reviewed, and 14 were included with 493,949 patients (mean age, 59.5 years; 55% men). The mean follow-up was 4.9 years. CRC incidence per 1000 person-years was 2.09 (95% confidence interval [CI], 1.29-2.90) for advanced SPs, 1.52 (95% CI, 0.78-2.25) for SPs of ≥10 mm, 5.86 (95% CI, 2.16-9.56) for SPs with dysplasia, 1.18 (95% CI, 0.77-1.60) for proximal SPs, 0.52 (95% CI, 0.08-1.12) for ≥3 SPs, 0.50 (95% CI, 0.35-0.66) for nonadvanced SPs, and 0.44 (95% CI, 0.41-0.46) for normal colonoscopy findings. Metachronous CRC risk was higher in advanced SPs versus nonadvanced SPs (RR, 1.84; 95% CI, 1.11-3.04) and versus normal colonoscopy findings (RR, 2.92; 95% CI, 2.26-3.77), in SPs of ≥10 mm versus <10 mm (RR, 2.61; 95% CI, 1.43-4.77) and versus normal colonoscopy findings (RR: 3.52; 95% CI, 2.17-5.69); and in SPs with dysplasia versus normal colonoscopy findings (RR: 2.71; 95% CI, 2.00-3.67). No increase in CRC or advanced polyp risk was found in patients with proximal versus distal SPs, nor in ≥3 SPs versus 1 or 2 SPs. Conclusions: CRC risk is significantly higher in patients with baseline advanced SPs after 4.9 years of follow-up, with risk magnitudes similar to those described for AA, supporting the current recommendation for 3-year surveillance in patients with advanced SPs

    Sensitivity of bile acid transport by organic anion-transporting polypeptides to intracellular pH

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    AbstractWe investigated the influence of intracellular pH (pHi) on [14C]-glycocholate (GC) uptake by human hepatoblastoma HepG2 cells that express sodium-independent (mainly OATP-A and OATP-8), but not sodium-dependent, GC transporters. Replacement of extracellular sodium by choline (Chol) stimulated GC uptake but did not affect GC efflux from loaded cells. Amiloride or NaCl replacement by tetraethylammonium chloride (TeACl) or sucrose also increased GC uptake. All stimulating circumstances decreased pHi. By contrast, adding to the medium ammonium or imidazole, which increased pHi, had no effect on GC uptake. In Chinese hamster ovary (CHO) cells expressing rat Oatp1, acidification of pHi had the opposite effect on GC uptake, that is, this was reduced. Changes in extracellular pH (pHo) between 7.40 and 7.00 had no effect on GC uptake at pHi 7.30 or 7.45 when pHo<pHi. However, GC uptake was inhibited at pHo 7.40 and 7.80 when pHo>pHi. Inhibition was not proportional to the pHo−pHi difference. Intracellular acidification decreased Vmax, but had no effect on Km. In sum, sodium-independent GC transport can be affected by intracellular acidification, possibly due both to modifications in the driving forces and to the particular response to protonation of carrier proteins involved in this process

    Formulación de aguas saborizadas

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    Fil: Bertero, C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Tecnología Química Industrial; Argentina.Fil: Mangas Flores, B. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Tecnología Química Industrial; Argentina.Fil: Ribotta, P.D. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Tecnología Química Industrial; Argentina.Fil: Severini, H. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Tecnología Química Industrial; Argentina.El objetivo del proyecto realizado fue desarrollar, como tarea de extensión del Centro de Tecnología Química Industrial (CETEQUI), una línea de aguas saborizadas para una planta industrial de La Pampa que actualmente produce agua mineral, cumpliendo con ciertos lineamientos establecidos por su dueño. La satisfacción de esta solicitud implicó desarrollar un sistema material con determinadas propiedades organolépticas que, si bien la mayoría no permite una medición directa y objetiva, generan una percepción global a través de estímulos sensoriales que depende de factores personales y subjetivos pero estadísticamente mensurables en una población.http://www.efn.unc.edu.ar/departamentos/quimicaindustrial/CIEXIQ/Libro%20de%20actas_2014.pdfFil: Bertero, C. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Tecnología Química Industrial; Argentina.Fil: Mangas Flores, B. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Tecnología Química Industrial; Argentina.Fil: Ribotta, P.D. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Tecnología Química Industrial; Argentina.Fil: Severini, H. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Centro de Tecnología Química Industrial; Argentina.Ingeniería Química (plantas, productos

    El aceite de oliva en nutrición clínica

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    The different beneficial effects of olive oil have a rational and scientific basis due to advances in the knowledge of lipid metabolism. The evidence that for a similar plasma cholesterol concentration, the rate of cardiovascular deaths is lower in the Mediterranean countries than in other ones, suggests that the beneficial effects of olive oil may not be only related to the known quantitative changes in plasma lipoproteins, but also to other, as yet unknown or little known, anti-atherogenic factors. The peculiarities of olive oil in terms of certain biochemical, biological and nutritional characteristics, open up a field of application in normal clinical practice. The benefits of olive oil in clinical nutrition correlate with its action on lipid metabolism and the cardiovascular system. Even a moderate increase in the ingestion of monounsaturated fats and a reduction in the ingestion of carbohydrates could be more advantageous in those patients with diabetes and hypertriglyceridemia and/or in those where loss of weight is not a priority. Different studies have also demonstrated the benefits of olive oil in different inflammatory and autoimmune diseases, such as rheumatoid arthritis. The chemical composition of extra virgin olive oil contributes to daily requirements of essential fatty acids and active antioxidant nutrients in vitamin E deficiency. This particular and well-balanced situation [oleic acid (18:1 n -9) and minor components in an ideal ratio] undoubtedly has a significant relevance in human clinical nutrition.Los avances en el conocimiento del metabolismo lipídico están permitiendo establecer las bases científicas de los efectos saludables del aceite de oliva. En los países del área Mediterránea, la mortalidad cardiovascular es menor que en otros, aunque la concentración de colesterol en sangre es similar. Es muy probable que la capacidad cardio-protectora del aceite de oliva se relacione con otros factores de riesgo, algunos de los cuales son poco o completamente desconocidos. Las propiedades bioquímicas, biológicas y nutricionales del aceite de oliva son peculiares y permiten su aplicación en la nutrición clínica. Los beneficios del aceite de oliva se correlacionan con su acción sobre el metabolismo lipídico y el sistema cardiovascular. Un aumento moderado en la ingesta de grasa monoinsaturada (aceite de oliva), a expensas de los carbohidratos, es la recomendación en pacientes con diabetes e hipertrigliceridemia. En nutrición clínica, el aceite de oliva también tiene efectos beneficiosos en enfermedades relacionadas con respuestas inflamatorias y autoinmunes, como la artritis reumatoide. La composición química del aceite de oliva virgen extra contribuye a las necesidades diarias de ácidos grasos esenciales y de antioxidantes, especialmente en situaciones patológicas de deficiencia en vitamina E. Sin duda, el aceite de oliva (virgen extra) tiene máxima relevancia, por su contenido de ácido oleico (18:1 n -9) y compuestos minoritarios, en la nutrición clínica

    Spanish children's diet: compliance with nutrient and food intake guidelines

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    OBJECTIVE: To compare the diet of Spanish children against the nutrient and food intake guidelines. To calculate an index of overall diet quality and check its validity against nutrient intake. DESIGN AND SETTING: Cross-sectional study in four cities in Spain, where information on food and nutrient intake was obtained from schoolchildren through a food frequency questionnaire. PARTICIPANTS: The sample included 1112 children (overall response rate of 85%) attending public and private schools and aged 6-7 y. Children were selected through random cluster sampling in schools, and stratified by sex and socioeconomic level. MAIN OUTCOME MEASURES: Mean nutrient intake, number of food servings, and the percentage of children who meet recommended nutrient and food-serving intake levels. The overall dietary quality was assessed using the Healthy Eating Index (HEI). RESULTS: Mean micronutrient intake exceeded 100% of the recommended dietary allowances, except for vitamin B6, which registered a mean intake of 77.1%. For almost all children, intake of saturated fat was above, and that of carbohydrate below, the recommended level, in contrast to the relatively high compliance with the recommendations for poly- and monounsaturated fatty acid, salt and fiber intake (69.7, 43.7, 40.7, and 30.1%, respectively). Consumption of food servings for each of the five American pyramid food groups came close to or exceeded USDA guidelines, with the exception of cereals, with 5.4 servings per day. The mean score obtained in the HEI was 64.6. Children who complied with all the food guide pyramid recommendations registered a higher dietary variety and a healthier nutritional profile. CONCLUSIONS: Children aged 6-7 y show scant compliance with the macronutrient goals for healthy eating. Micronutrient intake is adequate in general, yet there are small groups of children with risk of deficient intake of vitamins B6 and D. While Spanish children's eating habits are reasonably in line with American food guide pyramid guidelines, consumptions of cereals and fruit should be improved.This study was partly funded by grants from the Inter-national Olive Oil Board (Consejo Oleı ́cola Internacional),Comunidad de Madrid, Fundacio ́n Pedro Barrie ́de laMaza, and Fundacio ́n Eugenio Rodrı ́guez Pascua

    Prospective analysis of psychological differences between adult and elderly cancer patients during postoperaritve adjuvant chemotherapy

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    PURPOSE: Despite the burgeoning geriatric population with cancer and the importance of understanding how age may be related to mental adjustment and quality of life so far, differences in coping strategies and psychological harm between the elderly and adults are hardly being taken into account to modify the approach to this population. The aim of this prospective study is to describe the differences in psychological characteristics between older and adult cancer patients and examine dissimilarities in their psychological evolution during adjuvant chemotherapy. METHODS: Adults (18-69 years old) and older patients (≥ 70) with newly diagnosed non-metastatic resected cancer admitted to receive adjuvant chemotherapy were recruited. Patients completed the following questionnaires: mini-mental adjustment to cancer, brief symptom inventory, shared decision-making questionnaire-patient's version, multidimensional scale of perceived social support, EORTC quality-of-life instrument, life orientation test-revised, and satisfaction with life scale. RESULTS: 500 cancer patients (394 adults and 106 older) were evaluated. The impact of the diagnosis was less negative among older patients, with no differences in coping strategies, quality of life, or search for support. Regarding psychological changes from the beginning to the end of the adjuvant treatment, both age groups reported more somatic symptoms, increased psychological difficulty, reduced coping strategies, and a significant decrease in quality of life at the end of postoperative chemotherapy. CONCLUSION: Although there were clear psychological differences between adults and senior cancer patients, their evolution during adjuvant chemotherapy was similar, with deterioration in quality of life and coping. This negative psychological impact of adjuvant chemotherapy should be taken into account when considering interventions
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