Breaking waves on a dynamic Hele-Shaw beach

We report the formation of quasi-steady beaches and dunes via breaking waves in our tabletop ‘Hele-Shaw’ beach experiment. Breaking waves are generated by a wave maker, and zeolite particles act as sand. The tank is narrow, just over one-particle diameter wide, creating a quasi-2D set-up. Classical breaker types are observed on a time-scale of about a second. Beach formation under breakers occurs on a longer time-scale, and is a matter of minutes for a range of mono-chromatic wave frequencies. Alternating the wave maker motion between two frequencies generally leads to beach formation but occasionally to formation of a stable dune with water on either side. Finally, the Hele-Shaw configuration explored here experimentally lends itself to multi-scale modeling of beach dynamics

Revisiting Hele-Shaw dynamics to better understand beach evolution

Wave action, particularly during storms, drives the evo lution of beaches. Beach evolution by non-linear break ing waves is poorly understood due to its three-dimensional character, the range of scales involved, and our limited understanding of particle-wave interactions. We show how a novel, three-phase extension to the classic “Hele-Shaw” laboratory experiment can be designed that creates beach morphologies with breaking waves in a quasi-two-dimensional setting. Our thin Hele-Shaw cell simplifies the inherent complexity of three-phase dynamics: all dynamics become clearly visible and measurable. We show that beaches can be created in tens of minutes by several types of breaking waves, with about one-second periods. Quasi-steady beach morphologies emerge as function of initial water depth, at-rest bed level and wave-maker frequency. These are classified mathematically and lead to beaches, berms and sand bars

Annual report Bureau REACH 2016 : Taking care of chemicals

Chemische stoffen zijn niet weg te denken uit onze maatschappij, van weekmakers in plastic, brandvertragers in matrassen tot oplosmiddelen in verf. Om ervoor te zorgen dat veilig met deze stoffen wordt omgegaan, zowel tijdens de productie als bij het gebruik, is er Europese wetgeving opgesteld. De belangrijkste zijn twee Europese verordeningen: REACH (registratie, evaluatie, autorisatie en restrictie van chemische stoffen) ) en CLP (classificatie, labelling en packaging van stoffen en mengsels). In opdracht van de ministeries I&M, VWS en SZW ondersteunt en adviseert Bureau REACH van het RIVM de uitvoering van deze Europese wetgeving. Dit jaarverslag beschrijft de activiteiten in hoofdlijnen over 2016 en belicht enkele specifieke cases. Bureau REACH stelt onder andere dossiers op om aanvullende informatie over de schadelijkheid van een stof te vragen, of om de stof te identificeren als zeer ernstige zorgstof. Ook kan de classificatie van een stof Europees worden vastgesteld. Verder beoordeelt Bureau REACH dossiers die door andere landen en de industrie worden ingediend.Chemical substances are everywhere in our society, like plasticizers in polymers, flame-retardants in matrasses and solvents in paints. European legislation guarantees the safe production and use of these substances. The two main regulations in Europe are: REACH (registration, evaluation, authorization and restriction of chemicals) and CLP (classification, labelling and packaging of substances and mixtures). On behalf of the Ministries I&M, VWS and SZW, RIVM Bureau REACH supports and advices on the implementation of this European legislation. This annual report describes the main activities in 2016 and highlights some specific cases. Bureau REACH prepares for instance dossiers to request addition toxicological information on the properties of a substance, or to identify a chemical as substance of very high concern. In addition, a harmonized classification in Europa can be determined. Furthermore, Bureau REACH assesses dossiers prepared by other Member States and by industry.Ministerie van I&M, Ministerie van VWS, Ministerie van SZ

Definition of the σW regulon of Bacillus subtilis in the absence of stress

Bacteria employ extracytoplasmic function (ECF) sigma factors for their responses to environmental stresses. Despite intensive research, the molecular dissection of ECF sigma factor regulons has remained a major challenge due to overlaps in the ECF sigma factor-regulated genes and the stimuli that activate the different ECF sigma factors. Here we have employed tiling arrays to single out the ECF σW regulon of the Gram-positive bacterium Bacillus subtilis from the overlapping ECF σX, σY, and σM regulons. For this purpose, we profiled the transcriptome of a B. subtilis sigW mutant under non-stress conditions to select candidate genes that are strictly σW-regulated. Under these conditions, σW exhibits a basal level of activity. Subsequently, we verified the σW-dependency of candidate genes by comparing their transcript profiles to transcriptome data obtained with the parental B. subtilis strain 168 grown under 104 different conditions, including relevant stress conditions, such as salt shock. In addition, we investigated the transcriptomes of rasP or prsW mutant strains that lack the proteases involved in the degradation of the σW anti-sigma factor RsiW and subsequent activation of the σW-regulon. Taken together, our studies identify 89 genes as being strictly σW-regulated, including several genes for non-coding RNAs. The effects of rasP or prsW mutations on the expression of σW-dependent genes were relatively mild, which implies that σW-dependent transcription under non-stress conditions is not strictly related to RasP and PrsW. Lastly, we show that the pleiotropic phenotype of rasP mutant cells, which have defects in competence development, protein secretion and membrane protein production, is not mirrored in the transcript profile of these cells. This implies that RasP is not only important for transcriptional regulation via σW, but that this membrane protease also exerts other important post-transcriptional regulatory functions

In the air tonight: satellite-based air quality data and inclusive development in Africa: a scoping review of the literature

ASC – Publicaties niet-programma gebonde

From Surviving Cancer to Getting on With Life: Adult Testicular Germ Cell Tumor Survivors' Perspectives on Transition From Follow-Up Care to Long-Term Survivorship

With an increasing incidence and a high cure rate, a growing number of testicular germ cell tumor (TGCT) survivors require specialized follow-up care. However, knowledge of these patients' needs is lacking, leaving TGCT survivors with unmet care needs at risk of symptom burden when transitioning to long-term survivorship. This grounded theory study aimed to understand the perspectives of TGCT survivors' transition from follow-up care to long-term survivorship. A total of 12 adult TGCT survivors in follow-up care or completion less than a year were in-depth semi-structured interviewed. Interviews were audiotaped and transcribed verbatim. Transcripts were analyzed by constant comparison, and the core category "Dealing with back-and-forth forces" emerged in the integrated concepts. Two comparative processes in dealing with those forces were identified: the process of Living beyond the sword of Damocles involved the transition from feeling threatened by cancer to overcoming those threats; the process of Getting on with one's life can be described as transitioning from a period where cancer overruled their lives to carrying on with everyday life. The processes toward long-term survivorship follow general characteristics; the transition itself is an individual journey that depends on (life) experiences. The constructed model can guide healthcare professionals and researchers involved in TGCT survivorship to understand TGCT survivors' individual and ensuing needs. When TGCT survivors receive individualized and tailored follow-up care, it can assist in preventing and reducing long-term and late effects on long-term survivorship

Perspectives and Concerns on Late Effects Regarding Sexuality among Adolescents and Young Adults Treated for Testicular Germ Cell Tumor: The PRICELESS-Study-A Qualitative Study

This study aimed to explore perspectives and concerns regarding sexuality among adolescents and young adults (AYAs) possibly experiencing late effects after testicular germ cell tumor (TGCT) treatment. A qualitative study was performed in which semi-structured interviews were held with thirteen AYAs from a center of expertise for TGCT in the Netherlands. Data were analyzed using Braun and Clark's thematic analysis method. Seven interacting and interconnected themes were found: desire to have children, rediscovering sexuality, insecurity about sexual performance, acceptance of physical change, loss of masculinity, burden on relationship, and openness in discussing sexuality. Concerns about the desire to have children seem to play a significant role. In conclusion, TGCT patients face multiple changes (physical, emotional, relational, and sexual), followed by a difficult period of acceptance, after which a new phase of rediscovering sexuality appeared. These findings can help to make healthcare professionals aware of the underlying mechanisms and concerns about sexuality. Furthermore, insights can help to develop sexuality-themed items for a broader monitoring tool to structurally assess the late effects to support discussing sexuality

Prolonged fibroblast growth factor 19 response in patients with primary sclerosing cholangitis after an oral chenodeoxycholic acid challenge

Bile salts likely contribute to liver injury in patients with primary sclerosing cholangitis (PSC) and primary biliary cholangitis (PBC). Fibroblast growth factor 19 (FGF19) is a bile salt-induced enterokine with hepatoprotective potential as it suppresses de novo bile salt synthesis. Here, we evaluated the bile salt receptor FXR/FGF19 gut-liver axis in PSC and PBC patients. Fasted patients with PSC (n = 12) and PBC (n = 10), and healthy controls (HC; n = 10) were orally challenged with the natural FXR agonist chenodeoxycholic acid (CDCA 15 mg/kg). Blood was sampled hourly until 8 h afterwards. Serum FGF19 and bile salt excursions were determined. Serum levels of 7 alpha-hydroxy-4-cholesten-3-one (C4), reflecting bile salt synthesis, were measured as a biomarker of FGF19 response. Baseline serum FGF19 levels were comparable between groups, while fasted bile salt levels in PSC patients were elevated. Upon CDCA challenge, HC and PBC patients showed a serum FGF19 peak after 4 h followed by a decline. PSC patients showed a prolonged and elevated serum FGF19 response up to 8 h, combined with a sustained serum elevation of CDCA and other bile salts. In general, C4 levels declined following FGF19 elevation. In PSC patients with less favorable prognosis, baseline C4 levels were drastically suppressed and did not further decline. Following an oral CDCA challenge, PSC patients showed an impaired clearance of CDCA and a prolonged serum FGF19 response. FXR agonist therapy in PSC could cause prolonged exposure to elevated levels of FGF19, and we propose careful monitoring for detrimental side effects in patient studies

Oral ribose supplementation in dystroglycanopathy:A single case study

Three forms of muscular dystrophy-dystroglycanopathies are linked to the ribitol pathway. These include mutations in the isoprenoid synthase domain-containing protein (ISPD), fukutin-related protein (FKRP), and fukutin (FKTN) genes. The aforementioned enzymes are required for generation of the ribitol phosphate linkage in the O-glycan of alpha-dystroglycan. Mild cases of dystroglycanopathy present with slowly progressive muscle weakness, while in severe cases the eyes and brain are also involved. Previous research showed that ribose increased the intracellular concentrations of cytidine diphosphate-ribitol (CDP-ribitol) and had a therapeutic effect. Here, we report the safety and effects of oral ribose supplementation during 6 months in a patient with limb girdle muscular dystrophy type 2I (LGMD2I) due to a homozygous FKRP mutation. Ribose was well tolerated in doses of 9 g or 18 g/day. Supplementation with 18 g of ribose resulted in a decrease of creatine kinase levels of 70%. Moreover, metabolomics showed a significant increase in CDP-ribitol levels with 18 g of ribose supplementation (p &lt; 0.001). Although objective improvement in clinical and patient-reported outcome measures was not observed, the patient reported subjective improvement of muscle strength, fatigue, and pain. This case study indicates that ribose supplementation in patients with dystroglycanopathy is safe and highlights the importance for future studies regarding its potential effects.</p