Effectiveness of distributed temperature measurements for early detection of piping in river embankments

Abstract. Internal erosion is the cause of a significant percentage of failure and incidents involving both dams and river embankments in many countries. In the past 20 years the use of fibre-optic Distributed Temperature Sensing (DTS) in dams has proved to be an effective tool for the detection of leakages and internal erosion. This work investigates the effectiveness of DTS for dike monitoring, focusing on the early detection of backward erosion piping, a mechanism that affects the foundation layer of structures resting on permeable, sandy soils. The paper presents data from a piping test performed on a large-scale experimental dike equipped with a DTS system together with a large number of accompanying sensors. The effect of seepage and piping on the temperature field is analysed, eventually identifying the processes that cause the onset of thermal anomalies around piping channels and thus enable their early detection. Making use of dimensional analysis, the factors that influence this thermal response of a dike foundation are identified. Finally some tools are provided that can be helpful for the design of monitoring systems and for the interpretation of temperature data

Geobrain: Dutch Feasibility Database for Installing Sheet Pile Walls

In this paper it is shown how the knowledge embedded in case histories can be used to explicate some of the uncertainties contributing to the gap between theory and practice. With the help of computational intelligence techniques, collections of case histories in data-bases, as a type of collective memory of the geotechnical profession may be explored to turn this memory into collective brains in geo-technics: a GeoBrain. Regarding the scarcity of soil investigation data and the translation of the available data into a model, the ‘schematization factor’ has been introduced as a partial safety factor to account for the influence of data availability and the role of human expertise. Using a database of increasing size on the feasibility of installing sheet pile walls, the determination of optimal parameter values for prediction models is illustrated. It is shown that computational intelligence techniques like Bayesian Belief Networks and Genetic Algorithms can be very helpful to improve predictions of what is likely to happen in geotechnical practice

Lessons Learned from a Full-Scale Dyke Failure Test

A full-scale failure test has been performed on an old river dyke in the Netherlands, to determine its actual strength against failure due to the uplift mechanism and to validate the Van model for the stability analysis of dykes prone to uplift induced failure. The test has been a success and clearly showed the relevance and significance of the uplift mechanism. In combination with earlier verifications, the Van model was found to be suitable, which has already lead to significant reductions on dyke reinforcement projects. The large gap between the actual strength and the calculated strength was confirmed. This gap appeared to be partly necessary because of the large variation in the results of dyke stability analyses by different geotechnical consultants. For the near future, the test may serve as an important benchmark for the development of a more rationally based safety philosophy

A fast and cost-effective approach to develop and map EST-SSR markers: oak as a case study

Background: Expressed Sequence Tags (ESTs) are a source of simple sequence repeats (SSRs) that can be used to develop molecular markers for genetic studies. The availability of ESTs for Quercus robur and Quercus petraea provided a unique opportunity to develop microsatellite markers to accelerate research aimed at studying adaptation of these long-lived species to their environment. As a first step toward the construction of a SSR-based linkage map of oak for quantitative trait locus (QTL) mapping, we describe the mining and survey of EST-SSRs as well as a fast and cost-effective approach (bin mapping) to assign these markers to an approximate map position. We also compared the level of polymorphism between genomic and EST-derived SSRs and address the transferability of EST-SSRs in Castanea sativa (chestnut). Results: A catalogue of 103,000 Sanger ESTs was assembled into 28,024 unigenes from which 18.6% presented one or more SSR motifs. More than 42% of these SSRs corresponded to trinucleotides. Primer pairs were designed for 748 putative unigenes. Overall 37.7% (283) were found to amplify a single polymorphic locus in a reference fullsib pedigree of Quercus robur. The usefulness of these loci for establishing a genetic map was assessed using a bin mapping approach. Bin maps were constructed for the male and female parental tree for which framework linkage maps based on AFLP markers were available. The bin set consisting of 14 highly informative offspring selected based on the number and position of crossover sites. The female and male maps comprised 44 and 37 bins, with an average bin length of 16.5 cM and 20.99 cM, respectively. A total of 256 EST-SSRs were assigned to bins and their map position was further validated by linkage mapping. EST-SSRs were found to be less polymorphic than genomic SSRs, but their transferability rate to chestnut, a phylogenetically related species to oak, was higher. Conclusion: We have generated a bin map for oak comprising 256 EST-SSRs. This resource constitutes a first step toward the establishment of a gene-based map for this genus that will facilitate the dissection of QTLs affecting complex traits of ecological importance

RNA expression profiling in brains of familial hemiplegic migraine type 1 knock-in mice

Background Various CACNA1A missense mutations cause familial hemiplegic migraine type 1 (FHM1), a rare monogenic subtype of migraine with aura. FHM1 mutation R192Q is associated with pure hemiplegic migraine, whereas the S218L mutation causes hemiplegic migraine, cerebellar ataxia, seizures, and mild head trauma-induced brain edema. Transgenic knock-in (KI) migraine mouse models were generated that carried either the FHM1 R192Q or the S218L mutation and were shown to exhibit increased CaV2.1 channel activity. Here we investigated their cerebellar and caudal cortical transcriptome. Methods Caudal cortical and cerebellar RNA expression profiles from mutant and wild-type mice were studied using microarrays. Respective brain regions were selected based on their relevance to migraine aura and ataxia. Relevant expression changes were further investigated at RNA and protein level by quantitative polymerase chain reaction (qPCR) and/or immunohistochemistry, respectively. Results Expression differences in the cerebellum were most pronounced in S218L mice. Particularly, tyrosine hydroxylase, a marker of delayed cerebellar maturation, appeared strongly upregulated in S218L cerebella. In contrast, only minimal expression differences were observed in the caudal cortex of either mutant mice strain. Conclusion Despite pronounced consequences of migraine gene mutations at the neurobiological level, changes in cortical RNA expression in FHM1 migraine mice compared to wild-type are modest. In contrast, pronounced RNA expression changes are seen in the cerebellum of S218L mice and may explain their cerebellar ataxia phenotyp

Copeptin does not accurately predict disease severity in imported malaria

<p>Abstract</p> <p>Background</p> <p>Copeptin has recently been identified to be a stable surrogate marker for the unstable hormone arginine vasopressin (AVP). Copeptin has been shown to correlate with disease severity in leptospirosis and bacterial sepsis. Hyponatraemia is common in severe imported malaria and dysregulation of AVP release has been hypothesized as an underlying pathophysiological mechanism. The aim of the present study was to evaluate the performance of copeptin as a predictor of disease severity in imported malaria.</p> <p>Methods</p> <p>Copeptin was measured in stored serum samples of 204 patients with imported malaria that were admitted to our Institute for Tropical Diseases in Rotterdam in the period 1999-2010. The occurrence of WHO defined severe malaria was the primary end-point. The diagnostic performance of copeptin was compared to that of previously evaluated biomarkers C-reactive protein, procalcitonin, lactate and sodium.</p> <p>Results</p> <p>Of the 204 patients (141 <it>Plasmodium falciparum</it>, 63 non-falciparum infection), 25 had severe malaria. The Area Under the ROC curve of copeptin for severe disease (0.66 [95% confidence interval 0.59-0.72]) was comparable to that of lactate, sodium and procalcitonin. C-reactive protein (0.84 [95% CI 0.79-0.89]) had a significantly better performance as a biomarker for severe malaria than the other biomarkers.</p> <p>Conclusions</p> <p>C-reactive protein but not copeptin was found to be an accurate predictor for disease severity in imported malaria. The applicability of copeptin as a marker for severe malaria in clinical practice is limited to exclusion of severe malaria.</p

Sediment transport in non-linear skewed oscillatory flows : the TRANSKEW experiments

Peer reviewedPreprin

Fabrication of Atomically Precise Nanopores in Hexagonal Boron Nitride

We demonstrate the fabrication of individual nanopores in hexagonal boron nitride (hBN) with atomically precise control of the pore size. Previous methods of pore production in other 2D materials create pores of irregular geometry with imprecise diameters. By taking advantage of the preferential growth of boron vacancies in hBN under electron beam irradiation, we are able to observe the pore growth via transmission electron microscopy, and terminate the process when the pore has reached its desired size. Careful control of beam conditions allows us to nucleate and grow individual triangular and hexagonal pores with diameters ranging from subnanometer to 6nm over a large area of suspended hBN using a conventional TEM. These nanopores could find application in molecular sensing, DNA sequencing, water desalination, and molecular separation. Furthermore, the chemical edge-groups along the hBN pores can be made entirely nitrogen terminated or faceted with boron-terminated edges, opening avenues for tailored functionalization and extending the applications of these hBN nanopores.Comment: 5 pages, 6 figure

Influence of tumour size on the efficacy of targeted alpha therapy with 213Bi-[DOTA0,Tyr3]-octreotate

BACKGROUND: Targeted alpha therapy has been postulated to have great potential for the treatment of small clusters of tumour cells as well as small metastases. (213)Bismuth, an α-emitter with a half-life of 46 min, has shown to be effective in preclinical as well as in clinical applications. In this study, we evaluated whether (213)Bi-[DOTA(0), Tyr(3)]-octreotate ((213)Bi-DOTATATE), a (213)Bi-labelled somatostatin analogue with high affinity for somatostatin receptor subtype 2 (SSTR(2)), is suitable for the treatment of larger neuroendocrine tumours overexpressing SSTR(2) in comparison to its effectiveness for smaller tumours. We performed a preclinical targeted radionuclide therapy study with (213)Bi-DOTATATE in animals bearing tumours of different sizes (50 and 200 mm(3)) using two tumour models: H69 (human small cell lung carcinoma) and CA20948 (rat pancreatic tumour). METHODS: Pharmacokinetics was determined for calculation of dosimetry in organs and tumours. H69- or CA20948-xenografted mice with tumour volumes of approximately 120 mm(3) were euthanized at 10, 30, 60 and 120 min post injection of a single dose of (213)Bi-DOTATATE (1.5–4.8 MBq). To investigate the therapeutic efficacy of (213)Bi-DOTATATE, xenografted H69 and CA20948 tumour-bearing mice with tumour sizes of 50 and 200 mm(3) were administered daily with a therapeutic dose of (213)Bi-DOTATATE (0.3 nmol, 2–4 MBq) for three consecutive days. The animals were followed for 90 days after treatment. At day 90, mice were injected with 25 MBq (99m)Tc-DMSA and imaged by SPECT/CT to investigate possible renal dysfunction due to (213)Bi-DOTATATE treatment. RESULTS: Higher tumour uptakes were found in CA20948 tumour-bearing animals compared to those in H69 tumour-bearing mice with the highest tumour uptake of 19.6 ± 6.6 %IA/g in CA20948 tumour-bearing animals, while for H69 tumour-bearing mice, the highest tumour uptake was found to be 9.8 ± 2.4 %IA/g. Nevertheless, as the anti-tumour effect was more pronounced in H69 tumour-bearing mice, the survival rate was higher. Furthermore, in the small tumour groups, no regrowth of tumour was found in two H69 tumour-bearing mice and in one of the CA20948 tumour-bearing mice. No renal dysfunction was observed in (213)Bi-DOTATATE-treated mice after the doses were applied. CONCLUSIONS: (213)Bi-DOTATATE demonstrated a great therapeutic effect in both small and larger tumour lesions. Higher probability for stable disease was found in animals with small tumours. (213)Bi-DOTATATE was effective in different neuroendocrine (H69 and CA20948) tumour models with overexpression of SSTR(2) in mice. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13550-016-0162-2) contains supplementary material, which is available to authorized users