76 research outputs found

    Characterization of humic acids from low-rank coals by 13C-NMR and pyrolysis-methylation. Formation of benzenecarboxylic acid moieties during the coalification process

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    Instituto de Recursos Naturales y Agrobiologia de Sevilla, C.S.I.C., P.O. Box 1052, 41080-Seville, Spain; E-mail address: [email protected] acid (HA) fractions isolated from a peat and lignite deposit were studied by CP/MAS 13C-NMR and pyrolysis-methylation. Loss of carbohydrates, removal of methoxyls and formation of catechols during the coalification process was evident. Pyrolysis-methylation released a great variety of components, the lignin-derived monomers being the most prominent. A very striking feature was the release of benzenecarboxylic moieties after pyrolysis-methylation which have not been observed previously by pyrolytic techniques. These moieties were released in higher amounts from the lignite HA, suggesting that the content in carboxylic groups increase with coalification, at least up to the lignite stage. Oxidation of the C-3 side chain of the lignin structure would produce these benzenecarboxylic acids and benzylic ketones.We wish to thank the Comision Interministerial de Ciencia y Tecnologia (CICyT) for providing financial support (Project PB91-0074) and Professor H.-D. Lüdemann for recording NMR spectra.Peer reviewe

    Thermally assisted hydrolysis and alkylation of lignins in the presence of tetra-alkylammonium hydroxides

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    Three different milled lignins isolated from bamboo, pine and beech, corresponding to the three different structural groups, have been subjected to pyrolysis in the presence of tetramethylammonium hydroxide (TMAH) and tetrabutylammonium hydroxide (TBAH). Pyrolysis of the lignins in the presence of TMAH releases the methyl esters and methyl ethers of the different lignin monomers. Several moieties bearing carboxylic acid groups, not previously detected using pyrolytic techniques, could be released from the three lignins, suggesting that the presence of these moieties in the lignin structure have been underestimated.The authors wish to thank the CICyT (Spanish Direction General de Investigation Cientifica y Tecnica; Project PB91-0074) for financial support.Peer Reviewe

    Effect of Boriding on the Mechanical Properties of AISI 1045 Steel

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    Efecto en las propiedades mecánicas de un acero borurado 1045.Some mechanical properties of AISI 1045 borided steels were estimated in the present work. The boriding process was carried out by the powder pack method at 950°C with 8 h of treatment. The fatigue strength on borided notched specimens was evaluated with rotating bending tests (R=1) considering a stress concentration factor (Kt) of 2.53. Likewise, the presence of residual stresses in boride layers was established by the XRD technique. The Daimler-Benz Rockwell C test was used, also, to estimate the strength adhesion of the coated system. The results show a decrease in the fatigue strength of AISI borided steels due to the presence of high porosity in the layers. Finally, the Rockwell-C adhesion test showed no coating failure for the boride layer

    Estimation of the Evapotranspiration and Crop Coefficients of Bell Pepper Using a Removable Weighing Lysimeter: A Case Study in the Southeast of Spain

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    Water use efficiency is essential in semiarid regions of Spain, and it can be achieved through a precise knowledge of the real crop water requirements (CWR). The Food and Agriculture Organization of the United Nations (FAO) offers standardized crop coefficients to establish the CWR. However, these coefficients can change due to different conditions, such as climatic variations and cultivation practices. In this work, the evapotranspiration (ETClys) and crop coefficients (KClys) of bell pepper were obtained with a compact removable weighing lysimeter between February and August for two crop seasons (2019 and 2020). ETClys was determined from the water balance, and the KClys values were determined as the ratio of the crop evapotranspiration, measured on the removable weighing lysimeter, and the reference evapotranspiration. The KClys average values for the bell pepper in the initial, middle, and final stages were 0.57, 1.06, and 0.80, respectively. KC regression models were obtained as a function of the fraction thermal units, achieving a maximum correlation of 0.67 (R2). In general, the KC values obtained in this research work were lower in the initial and in the final stages and larger in the middle stage in comparison with the FAO-56 values and other research works values in semiarid conditions. The bell pepper yield increased by 7.72% in 2019 and by 3.49% in 2020 compared to the yield reported by the Ministry of the Environment and Rural and Marine Areas of the Spanish Government in 2019 and with a minimum water loss through drainage. The results in this work can help farmers to determine the crop water requirements and to improve the system efficiency in semiarid locations with similar conditions to those in the study

    A Compact Weighing Lysimeter to Estimate the Water Infiltration Rate in Agricultural Soils

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    Infiltration estimation is made by tests such as concentric cylinders, which are prone to errors, such as the lateral movement under the ring. Several possibilities have been developed over the last decades to compensate these errors, which are based on physical, electronic, and mathematical principles. In this research, two approaches are proposed to measure the water infiltration rate in a silty loam soil by means of the mass values of a lysimeter weighing under rainfall conditions and different moisture contents. Based on the fact that with the lysimeter it is possible to determine acting soil flows very precisely, then with the help of mass conservation and assuming a downward vertical movement, 12 rain events were analyzed. In addition, it was possible to monitor the behavior of soil moisture and to establish the content at field capacity from the values of the weighing lysimeter, from which both approach are based. The infiltration rate of these events showed a variable rate at the beginning of the rainfall until reaching a maximum, to descend to a stable or basic rate. This basic infiltration rate was 1.49 ± 0.36 mm/h, and this is because soils with fine textures have reported low infiltration capacity. Four empirical or semi-empirical models of infiltration were calibrated with the values obtained with our approaches, showing a better fit with the Horton’s model

    Systemic lupus erythematosus in northwestern Spain: a 20-year epidemiologic study

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    To further investigate the epidemiology of systemic lupus erythematosus (SLE) in southern Europe, we assessed the incidence, prevalence, clinical spectrum of the disease, flares, and survival of patients diagnosed with SLE in the Lugo region of northwestern Spain. Between January 1987 and December 2006, 150 Lugo residents were diagnosed as having SLE according to the 1982 American College of Rheumatology criteria for the classification of SLE. Women outnumbered men (127 [84.7%] vs. 23 [15.3%]). The mean age at the time of disease diagnosis was 46.1 ± 19.6 years. The mean follow-up from the time of disease diagnosis was 7.8 ± 4.5 years. The age- and sex-adjusted annual incidence rate over the 20-year study period was 3.6 (95% confidence interval [CI], 3.0-4.2) per 100,000 population aged 15 years and older. The overall annual incidence rate over the 20-year study period in women (5.9/100,000 population aged ≥15 yr; 95% CI, 4.9-7.0) was higher than in men (1.1/100,000 population aged ≥15 yr; 95% CI, 0.7-1.7) (p < 0.001). By December 31, 2006, the overall age-adjusted SLE prevalence in the Lugo region for patients who fulfilled at least 4 of 1982 American College of Rheumatology criteria was 17.5 per 100,000 population aged 15 years and older (95% CI, 12.6-24.1). Prevalence in women (29.2/100,000 population aged ≥15 yr; 95% CI, 20.0-40.7) was higher than in men (5.8/100,000 population aged ≥15 yr; 95% CI, 2.0-12.0). The most frequent clinical manifestation was arthritis. As reported in population-based studies on SLE patients of European descent, renal disease was observed in only 27.3% of the patients. The rate of flares was 0.084/year. A younger age and the presence of nephritis at the time of disease diagnosis were associated with the development of flares during the follow-up of Lugo patients. Compared with the general population the probability of survival in patients with SLE was significantly reduced (p = 0.04). In conclusion, the present study establishes a baseline estimate of the incidence and clinical spectrum of SLE in northwestern Spain. According to our results, the incidence of SLE in northwestern Spain is slightly higher than that reported in most European regions. Patients with SLE from northwestern Spain have a later average age onset and a lower frequency of nephritis than in the African-American population. However, our data show a reduced probability of survival in Spanish patients with SLE

    Análisis de la velocidad de infiltración del agua en el suelo saturados mediante lisímetros de pesada

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    La velocidad de infiltración permite estimar la penetración del agua en el suelo, se puede medir como una lámina en función de la profundidad y el tiempo. Existen algunos métodos para medir el comportamiento de la lámina de agua en el suelo. En esta investigación se empleó un lisímetro compacto desarrollado por el grupo de investigación Ingeniería Agromótica y del Mar de la Universidad Politécnica de Cartagena. Se instaló en una finca con suelo de textura franco- limosa, y se registraron los valores minutales del peso del recipiente de cultivo y del depósito de drenaje. Los resultados obtenidos permitieron conocer la evolución de la velocidad de infiltración a lo largo del tiempo. La máxima velocidad de infiltración fue de 0,093 mm/minuto, en el suelo saturado. Con los datos obtenidos en campo se calibró el modelo empírico de Kostiakov, con un error cuadrático medio de 0,00024. Se concluyó que con el empleo de los nuevos lisímetros de pesada que permiten conocer, en tiempo real, la velocidad de infiltración del agua en suelos saturados, es posible calibrar modelos matemáticos empíricos para su empleo cuando no se dispone de esta nueva tecnología. En el suelo franco-limoso estudiado, el comportamiento fue similar al descrito por Kostiakow, para el cual se obtuvo una ecuación exponencial calibrada.

    Mild hypophosphatasia may be twice as prevalent as previously estimated: an effective clinical algorithm to detect undiagnosed cases

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    Objectives: Since the prevalence of hypophosphatasia (HPP), a rare genetic disease, seems to be underestimated in clinical practice, in this study, a new diagnostic algorithm to identify missed cases of HPP was developed and implemented. Methods: Analytical determinations recorded in the Clinical Analysis Unit of the Hospital Universitario Clínico San Cecilio in the period June 2018 – December 2020 were reviewed. A new clinical algorithm to detect HPP-misdiagnosed cases was used including the following steps: confirmation of persistent hypophosphatasemia, exclusion of secondary causes of hypophosphatasemia, determination of serum pyridoxal- 5′-phosphate (PLP) and genetic study of ALPL gene. Results: Twenty-four subjects were selected to participate in the study and genetic testing was carried out in 20 of them following clinical algorithm criteria. Eighty percent of patients was misdiagnosed with HPP following the current standard clinical practice. Extrapolating these results to the current Spanish population means that there could be up to 27,177 cases of undiagnosed HPP in Spain. In addition, we found a substantial proportion of HPP patients affected by other comorbidities, such as autoimmune diseases (∼40 %). Conclusions: This new algorithm was effective in detecting previously undiagnosed cases ofHPP, which appears to be twice as prevalent as previously estimated for the European population. In the near future, our algorithm could be globally applied routinely in clinical practice to minimize the underdiagnosis of HPP. Additionally, some relevant findings, such as the high prevalence of autoimmune diseases in HPP-affected patients, should be investigated to better characterize this disorder.Instituto de Salud Carlos III grants PI21-01069 co-funded by the European Regional Development Fund (FEDER) and by Junta de Andalucía grant PI-0268-2019Operational Programme for Youth Employment of the Junta de Andalucía with Ref: POEJ_04/2022-12Instituto de Salud Carlos III with co-funding by FEDER (CD20/00022)(FI19/00118 and CM21/00221) from Instituto de Salud CarlosPostdoctoral fellowship from the Junta de Andalucía (RH-0141-2020

    PARP inhibition attenuates histopathological lesion in ischemia/reperfusion renal mouse model after cold prolonged ischemia

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    We test the hypothesis that PARP inhibition can decrease acute tubular necrosis (ATN) and other renal lesions related to prolonged cold ischemia/reperfusion (IR) in kidneys preserved at 4°C in University of Wisconsin (UW) solution. Material and Methods. We used 30 male Parp1+/+ wild-type and 15 male Parp10/0 knockout C57BL/6 mice. Fifteen of these wild-type mice were pretreated with 3,4-dihydro-5-[4-(1-piperidinyl)butoxyl]-1(2H)-isoquinolinone (DPQ) at a concentration of 15 mg/kg body weight, used as PARP inhibitor. Subgroups of mice were established (A: IR 45 min/6 h; B: IR + 48 h in UW solution; and C: IR + 48 h in UW solution plus DPQ). We processed samples for morphological, immunohistochemical, ultrastructural, and western-blotting studies. Results. Prolonged cold ischemia time in UW solution increased PARP-1 expression and kidney injury. Preconditioning with PARP inhibitor DPQ plus DPQ supplementation in UW solution decreased PARP-1 nuclear expression in renal tubules and renal damage. Parp10/0 knockout mice were more resistant to IR-induced renal lesion. In conclusion, PARP inhibition attenuates ATN and other IR-related renal lesions in mouse kidneys under prolonged cold storage in UW solution. If confirmed, these data suggest that pharmacological manipulation of PARP activity may have salutary effects in cold-stored organs at transplantation.Funding: This research was supported by CTS no. 138 Research Group and from the Carlos III Health Institute of the Spanish Ministery of Health and Consumer Affairs (Red de Investigación Renal, REDinREN 012/0021/0025). “FEDER una manera de hacer Europa”
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