RESUMEN
Cattle slurry storage is a major source of gaseous N emissions. The aim of this study was to evaluate the effects of biochar, clinoptilolite and elemental sulfur (S°) on (1) NH3 and greenhouse gas emissions during storage of cattle slurry and (2) after soil application of the enriched solid fractions; and (3) on the agronomic quality of the solid and liquid fractions. In the first phase, biochar was added to the slurry (10 g L-1); subsequently in the second phase, clinoptilolite (50 g L-1), S° (1 g L-1) and 40 g L-1 extra biochar were added. Gaseous emissions were monitored by a semi-continuous multi-gas analyzer and the agronomic quality of solid and liquid fractions was assessed after separation. The enriched solid fractions were applied to soil to study the effects on gaseous emissions, N and C mineralization. Amendment of biochar reduced NH3 emissions during cattle slurry storage by 12% during the first 7 days. Extra amendment of biochar, clinoptilolite and S° in combination with biochar resulted in a decrease of NH3 emissions of approximately 20%. The N sorbed from the slurry by the biochar was not released as NH3 during soil application of the solid fractions and was not released as mineral N in the short term (within 28 days). A short-term positive priming effect of biochar on the C mineralization of manure and biochar-manure mixture applied to soil was observed. The biochar-enriched solid fractions contained more C, total and organic N and water-available P with a slow release.
Asunto(s)
Suelo , Zeolitas , Bovinos , Animales , Estiércol , Nitrógeno/análisis , Gases , Carbón OrgánicoRESUMEN
Biochar amendment during biomass processing can improve those processes and products, and reduce the emissions of greenhouse gases and NH3, resulting in ecologic and economic benefits. The potential positive effects of biochar are related to NH4+-N and NH3 sorption, which in turn are depending on different biochar characteristics. By knowing the relationship between biochar characteristics and NH4+-N and NH3 sorption, biochar production can be steered towards a higher N sorption or existing biochars can be selected for targeted applications for high N sorption. Therefore, this study aims to develop fast screening tests to estimate the potential for both NH4+-N and NH3 sorption of biochar, before application in biomass processing. Further, the effects of feedstock, pyrolysis temperature, biochar characteristics and biochar treatments on N sorption are studied. The results show that NH4+-N sorption varied between 0 and 1.54 mg NH4+-N/g fresh biochar and was highest for manure-based biochars with a high nutrient content and cation exchange capacity, produced at lower temperatures (300-450 °C). For some biochars, the feedstock itself had a higher NH4+-N sorption than the biochar. Grinding and washing increased the NH4+-N sorption. In addition, a general linear model was proposed to predict the NH4+-N sorption based on three chemical characteristics· NH3 sorption varied between 0 and 100 % of the negative control and showed a linear positive relationship with the NH4+-N sorption, moisture retention factor and cation exchange capacity. Pyrolysis temperature and feedstock type did not significantly affect NH3 sorption. NH4+-N and NH3 desorption varied amongst biochar type.
Asunto(s)
Carbón Orgánico , Biomasa , Adsorción , Carbón Orgánico/química , CationesRESUMEN
Phytoextraction has a promising potential as an environmentally friendly clean-up method for soils contaminated with toxic metals. To improve the development of efficient phytoextraction strategies, better knowledge regarding metal uptake, translocation and detoxification in planta is a prerequisite. This review highlights our current understanding on these mechanisms, and their impact on plant growth and health. Special attention is paid to the central role of glutathione (GSH) in this process. Because of the high affinity of metals to thiols and as a precursor for phytochelatins (PCs), GSH is an essential metal chelator. Being an important antioxidant, a direct link between metal detoxification and the oxidative challenge in plants growing on contaminated soils is observed, where GSH could be a key player. In addition, as redox couple, oxidized and reduced GSH transmits specific information, in this way tuning cellular signalling pathways under environmental stress conditions. Possible improvements of phytoextraction could be achieved by using transgenic plants or plant-associated microorganisms. Joined efforts should be made to cope with the challenges faced with phytoextraction in order to successfully implement this technique in the field.
Asunto(s)
Glutatión/metabolismo , Metales/metabolismo , Plantas/metabolismo , Contaminantes del Suelo/metabolismo , Antioxidantes/metabolismo , Bacterias , Biodegradación Ambiental , Transporte Biológico , Quelantes/metabolismo , Hongos , Oxidación-Reducción , Fitoquelatinas/metabolismo , Desarrollo de la Planta , Plantas/microbiología , Plantas Modificadas Genéticamente , Compuestos de Sulfhidrilo/metabolismoRESUMEN
The aim of our study was to comparison of a thickness of endometrium and blood flow parameters measured by transvaginal ultrasonography with color and "power" angio Doppler. We examined 81 women in perimenopausal period. Blood flow characteristics and histopathological changes were evaluated. There were no endometrial changes in 34 women. We detected 22 perimenopausal women and 12 postmenopausal with endometrial hyperplasia. In 13 cases we find endometrial carcinoma, 10 in postmenopausal women. Transvaginal ultrasonography with color Doppler can be using to diagnose pathology of endometrium providing that all suspicious images will be verified by other more invasive method.
Asunto(s)
Endometrio , Posmenopausia/fisiología , Premenopausia/fisiología , Adulto , Anciano , Ecocardiografía Doppler en Color , Endometrio/anatomía & histología , Endometrio/irrigación sanguínea , Endometrio/diagnóstico por imagen , Femenino , Humanos , Persona de Mediana EdadRESUMEN
The objective of our study was to evaluate the predictive value of serum CA-125 levels and transvaginal ultrasound with color Doppler flow mapping (RI) in patients with benign and malignant ovarian tumors. The retrospective analysis included 78 women in whom 92 tumors were detected. Eleven patients had ovarian carcinoma (a total of 16 tumors). Predictive values were compared for tumor morphology, lowest resistive index (RI) < 0.40 and CA-125 > 35 IU/ml. Sensitivity, specificity, positive and negative predictive values in differentiating malignancy were highest for RI (94%, 87% 87% and 94%, respectively). Morphological criteria or CA-125 levels alone had lower predictive accuracy. Combining of the correctly identified all of the malignancies. It is concluded that preoperative transvaginal ultrasound with color Doppler flow mapping is valuable tool in the assessment of adnexal tumors and can be of assistance in prediction of ovarian cancer.