Escalera E.,Lulea University of Technology |
Escalera E.,San Simon University |
Garcia G.,Lulea University of Technology |
Teran R.,San Simon University |
And 3 more authors.
Construction and Building Materials | Year: 2015
Diatomaceous earth was mixed with Brazil nut shell ash (BNS ash) in different amounts between 0 and 30 wt% and sintered at temperatures between 750 and 950°C. The BNS ash contains 33 wt% K2O and 11 wt% CaO mainly in carbonate form. The addition of BNS ash into the diatomaceous earth caused significant changes of the microstructure after sintering. The BNS ash addition produces lightweight porous bricks with acceptable strength at lower sintering temperature. The best combination of strength and porosity was achieved for a mixture of 10 wt% of BNS ash in the diatomaceous earth sintered at 850°C. The achieved high porosity was 49%, density 1.06 g/cm3, thermal conductivity 0.20 W/(m K) and the compressive strength was 8.5 MPa. © 2015 Elsevier Ltd. All rights reserved.
Romero M.,San Simon University |
Canedo N.,San Simon University |
Segales R.,San Simon University
River Flow 2012 - Proceedings of the International Conference on Fluvial Hydraulics | Year: 2012
The present paper illustrates the experimental and numerical assessment of scouring processes around a pier, with four attack angles to the flow.A semi-circular nose and tail pier was placed in a flume with a constant bed slope and a single steady discharge. Uniform fine sand was used as mobile bed. 2D-Model IBER was implemented for the numerical assessment of hydrodynamic and scouring processes. Results show that IBER reproduces acceptably measured velocities in the physical model. However, eroded volumes were highly over estimated. It is observed that scouring processes are highly 3D and a local issue, where the hydrodynamic conditions and the sediment transport rates in the surrounding area would not be accurately represented by a 2D model like IBER. Scale factors may have had an influence on the obtained results, being necessary more tests with IBER in prototype piers with attack angles to assess more reliably these conclusions. © 2012 Taylor & Francis Group.
Lazarte C.E.,Lund University |
Lazarte C.E.,San Simon University |
Encinas M.E.,San Simon University |
Alegre C.,San Simon University |
Granfeldt Y.,Lund University
Nutrition Journal | Year: 2012
Background: Improvement of traditional methods for dietary assessment is necessary, especially in rural areas where it is more difficult to succeed with self-reporting methods. This study presents and validates a method for improving accuracy when measuring food and nutrient intake of individuals in rural areas. It is called the "Food photography 24-h recall method" (FP 24-hR) and is a modified 24-h recall with the addition of a digital food photography record and a photo atlas. Methods. The study was carried out in a rural area in the tropical region of Bolivia; 45 women participated. Validation of the method was made by comparing it with a reference method, the Weighed Food Record (WFR). During the FP 24-hR, digital photographs were taken by the subjects of all food consumed during a day and a 24-h recall questionnaire was conducted by an interviewer. An estimate of the amount of food consumed was made using a photo atlas and the photographs taken by the subjects. For validation, comparison was made between the calculations, by both methods, of the levels of food, and nutrient, intake. Results: The comparison was made in 10 food categories; most of which were somewhat underestimated from -2.3% (cassava) to -6.8% (rice), except for beverages (+1.6%) and leafy vegetables (+8.7%), which were overestimated. Spearman's correlation coefficients were highly significant (r from 0.75 for eggs to 0.98 for potato and cassava). Nutrient intakes calculated with data from both methods showed small differences from -0.90% (vitamin C) to -5.98% (fat). Although all nutrients were somewhat underestimated, Pearson§ssup§′§esup§s coefficients are high (>0.93 for all) and statistically significant. Bland Altman analysis showed that differences between both methods were random and did not exhibit any systematic bias over levels of food and nutrient intake, with acceptable 95% limits of agreement. Conclusion: The FP 24-hR exhibits acceptable differences when compared with a WFR, digital photos are useful as a memory aid for the subjects during 24-h recall and as an estimation tool. The method is suitable for assessing dietary intake among rural populations in developing countries. © 2012 Lazarte et al.; licensee BioMed Central Ltd.
Maldonado E.M.,Lund University |
Maldonado E.M.,San Simon University |
Svensson D.,Lund University |
Oredsson S.M.,Lund University |
Sterner O.,Lund University
Phytochemistry Letters | Year: 2014
A phytochemical study of the flowers of Kaunia lasiophthalma G. (Asteraceae) yielded a novel triterpene (1) together with several known sesquiterpenoids. The structure of the new compound was elucidated by analysis of the spectroscopic data. The biosynthetic origin of 1 is proposed to be a dimerization of an oxidized derivative (3) of the germacrane sesquiterpene costunolide (2), also present in the flowers. The anticancer activity of 1 in the five breast cancer cell lines HCC1937, JIMT-1, L56Br-C1, MCF-7 and SK-BR-3 was compared with the cytotoxicity in the normal-like breast epithelial cell line MCF-10A. 1 exhibited high cytotoxicity in all investigated cancer cell lines with IC50 values ranging from 0.67 to 7.0 μM, although it is lacking selectivity as the MCF-10A cells were almost as sensitive. © 2014 Phytochemical Society of Europe.
Bustamante R.,San Simon University |
Medieu A.,Agro ParisTech
Environmental Justice | Year: 2012
In the periphery of the city of Cochabamba, many communities are struggling to retain a diversity of options for their livelihoods and are resisting the illegal urbanization of agricultural land as well as the pollution generated by the dumping of most of the city's waste in the area. The struggle is aimed not only at maintaining the agrarian characteristics of the area and reversing environmental harm but also at drafting municipal plans of an alternative vision of the city that goes beyond an urban metropolis built only of cement and bricks. An important element for the realization of that vision is access to sufficient and clean water needed to carry out domestic and productive activities in better conditions. © 2012, Mary Ann Liebert, Inc.
Romero M.,San Simon University |
Ballesteros N.,San Simon University |
Lucana V.,San Simon University
Proceedings of the International Conference on Fluvial Hydraulics, RIVER FLOW 2014 | Year: 2014
The present paper illustrates the experimental assessment of scouring and deposition processes around several arrays of permeable gabion groynes with a number of attack angles to the flow. Four scaled T-head shape groynes made of stone were placed in a flume with a constant bed slope and a single steady discharge for submerged conditions. Uniform fine was used as mobile bed. Five attack angles and two separation lengths in between structures were tested. Results show that for each specific separation length, different attack angles produce the minimum scour depths and eroded volumes, largest deposited volumes in between structures, and less scouring velocities at three considered control sections. Therefore, individual attack angles were identified for specific tasks to be better accomplished by such arrays. However, it is acknowledged that more tests with different separation lengths or different sediment sizes of the bed are needed to improve the obtained conclusions. © 2014 Taylor & Francis Group, London.
Lopez R.R.,San Simon University |
Vincent L.,Wageningen University |
Rap E.,International Water Management Institute
International Journal of Water Resources Development | Year: 2015
The expansion of the Totora Khocha dam-based irrigation system in the Pucara watershed is a case of planned re-engineering of a closing watershed. This article shows how, when irrigation systems expand in space and across boundaries to capture new water, they also involve new claims by existing and emergent users. This results in complex processes of design, contestation and negotiated redesign, where irrigation projects are being produced by the negotiated construction of water networks. Therefore, the design process in a closing watershed is better approached as a dynamic and negotiated process of engineering than as a prescriptive mode of network building. © 2014, © 2014 Taylor & Francis.
Fernandez C.,Lund University |
Rojas C.C.,Lund University |
Rojas C.C.,San Simon University |
Nilsson L.,Lund University
International Journal of Biological Macromolecules | Year: 2011
In this paper we investigate the size, structure and scaling relationships in glycogen isolated from five different animal sources. For this purpose a versatile fractionation technique, asymmetrical flow field-flow fractionation (AsFlFFF), coupled to multi-angle light scattering, is utilized. For determination of the average degree of branching 1H NMR is utilized. The results give a detailed insight into the physico-chemical properties of glycogen over the whole size distribution. The results show that glycogen is a hyper branched macromolecule with wide size distributions, and in some samples two major populations are clearly observed which most likely correspond to β- and α-particles of glycogen. The results also illustrates that glycogen is a polysaccharide showing rather diverse conformational properties, over the size distribution, depending on its origin and the extraction procedure. The ratio between root-mean-square radius and hydrodynamic radius varies depending of both sample origin the molar mass of the macromolecules, reflecting differences in conformation and scaling within the size distribution. Thus, a priori assumptions regarding the r rms/r h are difficult to make and r rms/r h based on average properties give an incomplete description of the properties. Furthermore, the results display the strength of the apparent density (as obtained from AsFlFFF-MALS-RI) as a characterization parameter for scaling in disperse macromolecules. © 2011 Elsevier B.V.
Lazarte C.E.,Lund University |
Lazarte C.E.,San Simon University |
Carlsson N.-G.,Chalmers University of Technology |
Almgren A.,Chalmers University of Technology |
And 2 more authors.
Journal of Food Composition and Analysis | Year: 2015
The content of zinc, iron, calcium and phytate in the 16 most consumed foods from 5 villages in a tropical rural area of Bolivia was analyzed. The food items were selected according to a completed food frequency questionnaire. Minerals were analyzed by atomic absorption and phytates by HPIC chromatography. The molar ratios of phytate:mineral are presented as indication of the mineral bioavailability. Within the analyzed food, quinoa is a potential source of minerals: zinc 3.65, iron 5.40 and calcium 176. mg/100. g; however, it also has the highest content of phytate 2060. mg/100. g. Cereals and legumes showed high concentration of phytates (from 142 to 2070. mg/100. g), roots and tubers have lower concentrations (from 77 to 427. mg/100. g). In general, both phytate contents and molar ratios Phy:Zn (phytate:zinc), Phy:Fe (phytate:iron) and Phy:Ca (phytate:calcium) in most of the analyzed foods were at levels likely to inhibit the absorption of these minerals. Significant positive associations (. p<. 0.01) were found between the level of phytate and minerals in food, for zinc (. r=. 0.714), iron (. r=. 0.650) and calcium (. r=. 0.415). The results compared to data from USA or from Bolivia showed some discrepancies, confirming the need for more reliable data for dietary evaluations and interventions. © 2015 Elsevier Inc.
PubMed | Lund University and San Simon University
Type: | Journal: Food & nutrition research | Year: 2015
Zinc deficiency is a significant problem, in developing countries and in vegetarians, which can be caused by plant-based diets. Thus, dietary strategies, such as fermentation, to improve zinc bioavailability of diets should be investigated.To improve zinc bioavailability in a plant-based diet by the inclusion of fermented food.Cassava tubers were fermented and made to replace the unfermented cassava in a basal plant-based diet, and compared with plant-based diets with and without zinc supplement. The zinc bioavailability of the diets was evaluated in Wistar rats that were fed these diets for 28 days. The evaluation was for zinc apparent absorption (ZnAA), serum zinc levels, and zinc deposits in liver and femur; in addition, the feed efficiency ratio (FER) of the diets and femur weight (FW) of the rats were evaluated.During the cassava fermentation, lactic acid increased and pH decreased (from 6.8 to 3.9), which is favorable for native phytase activity, resulting in a 90.2% reduction of phytate content in cassava. The diet containing fermented cassava showed significantly higher levels of ZnAA, FER, and FW (p<0.001). Moreover, the zinc levels in serum and femur were significantly higher (p<0.001) compared with the results of the diet with unfermented cassava. The results clearly show a higher zinc bioavailability in the diet containing fermented cassava and are comparable with the results obtained with the plant-based diet with zinc supplement.In conclusion, the fermentation of cassava reduces the phytate content. The diet containing the fermented cassava represents a better nutritional alternative than the diet with unfermented cassava and is comparable with the zinc-supplemented diets.