Reconnaissance chimique et isotopique des eaux de pluie au Sénégal

L'étude de la composition chimique et isotopique des eaux de pluie au Sénégal, réalisée au cours de la saison des pluies de 1981, montre qu'il existe des sources différentes pour la vapeur génératrice des pluies de mousson et les aérosols porteurs de sels marins. Elle montre également que ces précipitations sont plus riches en sels que les eaux fluviatiles en provenance des hauts bassin du Sénégal et de la Gambi

Comment on “The extent of forest in dryland biomes”

Bastin et al. (Reports, 12 May 2017, p. 635) claim to have discovered 467 million hectares of new dryland forest. We would argue that these additional areas are not completely “new” and that some have been reported before. A second shortcoming is that not all sources of uncertainty are considered; the uncertainty could be much higher than the reported value of 3.5%

Validation of Automatically Generated Global and Regional Cropland Data Sets: The Case of Tanzania

There is a need to validate existing global cropland maps since they are used for different purposes including agricultural monitoring and assessment. In this paper we validate three recent global products (ESA-CCI, GlobeLand30, FROM-GC) and one regional product (Tanzania Land Cover 2010 Scheme II) using a validation data set that was collected by students through the Geo-Wiki tool. The ultimate aim was to understand the usefulness of these products for agricultural monitoring. Data were collected wall-to-wall for Kilosa district and for a sample across Tanzania. The results show that the amount of and spatial extent of cropland in the different products differs considerably from 8% to 42% for Tanzania, with similar values for Kilosa district. The agreement of the validation data with the four different products varied between 36% and 54% and highlighted that cropland is overestimated by the ESA-CCI and underestimated by FROM-GC. The validation data were also analyzed for consistency between the student interpreters and also compared with a sample interpreted by five experts for quality assurance. Regarding consistency between the students, there was more than 80% agreement if one difference in cropland category was considered (e.g., between low and medium cropland) while most of the confusion with the experts was also within one category difference. In addition to the validation of current cropland products, the data set collected by the students also has potential value as a training set for improving future cropland products

Increased calcium oxalate monohydrate crystal binding to injured renal tubular epithelial cells in culture

The retention of crystals in the kidney is considered to be a crucial step in the development of a renal stone. This study demonstrates the time-dependent alterations in the extent of calcium oxalate (CaOx) monohydrate (COM) crystal binding to Madin-Darby canine kidney (MDCK) cells during their growth to confluence and during the healing of wounds made in confluent monolayers. As determined by radiolabeled COM crystal binding studies and confirmed by confocal-scanning laser microscopy, relatively large amounts of crystals (10.4 +/- 0.4 micrograms/cm2) bound to subconfluent cultures that still exhibited a low transepithelial electrical resistance (TER < 400 omega.cm2). The development of junctional integrity, indicated by a high resistance (TER > 1,500 omega.cm2), was followed by a decrease of the crystal binding capacity to almost undetectable low levels (0.13 +/- 0.03 microgram/cm2). Epithelial injury resulted in increased crystal adherence. The highest level of crystal binding was observed 2 days postinjury when the wounds were already morphologically closed but TER was still low. Confocal images showed that during the repair process, crystals selectively adhered to migrating cells at the wound border and to stacked cells at sites were the wounds were closed. After the barrier integrity was restored, crystal binding decreased again to the same low levels as in undamaged controls. These results indicate that, whereas functional MDCK monolayers are largely protected against COM crystal adherence, epithelial injury and the subsequent process of wound healing lead to increased crystal binding

Metastatic potential of human renal cell carcinoma: experimental model using subrenal capsule implantation in athymic nude mice

The aim of this study was to determine whether subrenal capsule (SRC) implantation is a suitable model for the study of the metastatic potential of our human renal cell carcinoma (HRCC) lines and to establish new sublines with enhanced metastatic ability. NMRI athymic nude mice 7-11 weeks old received SRC implantation of our HRCC lines RC43 and RC21. These lines were not metastatic when implanted s.c. Mice were killed after 4 or 8 weeks, or when moribund. With the RC43 cell line the success rate for implantation was 69%, with 89% of these showing metastases. The average volume of the implanted tumour fragments was 0.5 mm3 (range 0.28-0.7), the average volume at the primary site at the time of death was 9087 (9-32000) mm3. Metastases were found in lymph nodes, liver, spleen, peritoneum, psoas muscle, pancreas, diaphragm and skin. The average volume of the metastases was 4139 (0.5-9000) mm3. Growing cell lines were established in vivo and in vitro from one splenic, one peritoneal, one diaphragmatic, and one hepatic metastasis. These sublines have faster in vivo and slower in vitro growth rates than the parental lines. With the RC21 cell line the success rate for implantation was 56% and the metastatic rate 78%. The average volume of the implanted tumour was 0.8 mm3 (0.28-1.2), the average volume at the primary site at the time of death was 2685 mm3 (1.4-6534) and the average volume of metastases was 7.1 mm3 (0.5-37.5). Metastases were found in lymph nodes, lung and skin. No establishment was attempted for RC21 because of the small dimensions of these metastases. SRC implantation is thus considered a useful tool for the study of the metastatic ability of our cell lines RC43 and RC21. The establishment of new sublines with a faster growth rate and an enhanced metastatic ability will be useful for further studies on the metastatic process

Glycosaminoglycans and other sulphated polysaccharides in calculogenesis of urinary stones

Naturally occurring glycosaminoglycans (GAGs) and other, semisynthetic, sulphated polysaccharides are thought to play an important role in urolithiasis. Processes involved in urinary stone formation are crystallization and crystal retention. Oxalate transport and renal tubular cell injury are determining factors in these processes. In this article experimental results concerning the possible mechanisms of action of GAGs and other sulphated polysaccharides are reviewed. GAGs are inhibitors of crystal growth and agglomeration and possibly also of nucleation. They can prevent crystal adherence, correct an abnormal oxalate flux and prevent renal tubular cell damage

The effects of a plant proteinase inhibitor from Enterolobium contortisiliquum on human tumor cell lines

Supplementary to the efficient inhibition of trypsin, chymotrypsin, plasma kallikrein, and plasmin already described by the EcTI inhibitor from Enterolobium contortisiliquum, it also blocks human neutrophil elastase (K(iapp)=4.3 nM) and prevents phorbol ester (PMA)-stimulated activation of matrix metalloproteinase (MMP)-2 probably via interference with membrane-type 1 (MT1)-MMP. Moreover, plasminogen-induced activation of proMMP-9 and processing of active MMP-2 was also inhibited. Furthermore, the effect of EcTI on the human cancer cell lines HCT116 and HT29 (colorectal), SkBr-3 and MCF-7 (breast), K562 and THP-1 (leukemia), as well as on human primary fibroblasts and human mesenchymal stem cells (hMSCs) was studied. EcTI inhibited in a concentration range of 1.0-2.5 mu M rather specifically tumor cell viability without targeting primary fibroblasts and hMSCs. Taken together, our data indicate that the polyspecific proteinase inhibitor EcTI prevents proMMP activation and is cytotoxic against tumor cells without affecting normal tissue remodeling fibroblasts or regenerative hMSCs being an important tool in the studies of tumor cell development and dissemination

Noodsaak van die verrekening van metateoretiese vertrekpunte in prakties-teologiese wetenskapsbeoefening

This article is the first in the research project “Metatheoretical assumptions in Practical Theology”. The research problem has to do with the lack of explicit expression of metatheoretical assumptions against the background of a plurality in scientific approaches to the discipline. Sometimes researchers do not explicity state their theological and other approaches. In this project a group of reformed practical theologians explicitly state their metatheoretical theological and other perspectives and explain their vantage points in researching the praxis. The necessity to explain metatheoretical assumptions pertaining to the assumptions about reality, the hermeneutical process in understanding, explaining and changing actions in praxis, and the nature and task of scientific research, is discussed from a reformed perspective.http://www.journals.co.za/ej/ejour_skrif.htm