61 research outputs found
Emission limit values for building materials. Environmental foundation and consequences for building materials
This report presents alternative emission limit values for inorganic components to be used in the revision of the Building Materials Decree (1999) in the Netherlands. Three key factors determine the emission limit value: (1) the environmental compartment under consideration, with its dimensions and the accounted for, (2) the desired level of environmental protection and (3) the scenario applying to the intended use of the construction material. Emission limit values have been derived here from modelled concentrations in soil, groundwater and surface water. The desired level of protection has been elaborated as a stand-still approach (based on quality target values and a risk-based approach (based on PNECs). Two exposure models were used for taking the effects of a time-dependent exposure of the soil to leached components into account, for vertical transport through the soil profile and for retardation of components in the soil profile. The PEARL model was used for binding described by equilibrium adsorption. The ORCHESTRA model was used for binding that also takes speciation into account. For surface water, a dilution factor was computed assuming a certain mixing zone, dependent on the size of the surface water. The consequences of the proposed alternative emission limit values have been estimated on the basis of information in a database containing results of leaching tests for construction materials. The alternatives proposed form the basis for a political decision-making process, where environmental protection will be balanced with other socio-economic concerns.In dit rapport worden varianten berekend die de huidige normen voor het hergebruik van bouwmaterialen - zoals vastgelegd in het Bouwstoffenbesluit 1999 - kunnen vervangen. De huidige normen vormden een belemmering voor het hergebruik van bouwmaterialen. Omdat er wel behoefte bestond aan hergebruik, zijn de mogelijkheden tot een eventuele verruiming, die wel milieuverantwoord blijft, onderzocht. Het bouwstoffenbesluit bevat normen voor de maximale uitstoot van anorganische stoffen (zoals metalen) in bouwmaterialen. Milieuhygienische belangen worden nu afgewogen tegen de wens tot ruimere mogelijkheden voor hergebruik. Het onderzoek houdt rekening met verschillende elementen bij het hergebruik van bouwmaterialen: het milieucompartiment, het gewenste beschermingsniveau en het toepassingsscenario van de bouwstof. Er zijn twee alternatieve computermodellen gebruikt, die de verschillen in de wijzen waarop vrijgekomen stoffen zich aan de bodem binden, berekenen. Daarnaast is ook de menging van vrijgekomen stoffen voor oppervlaktewater berekend. De berekende waarden zijn afgezet tegen de kwaliteitsgegevens van bouwstoffen die door verschillende bedrijfstakken zijn aangeleverd. De voorgestelde varianten maken onderdeel uit van een beleidsmatig besluitvormingsproces, waarbij ook andere socio-economische aspecten worden afgewogen
A Sex-Specific Metabolite Identified in a Marine Invertebrate Utilizing Phosphorus-31 Nuclear Magnetic Resonance
Hormone level differences are generally accepted as the primary cause for sexual dimorphism in animal and human development. Levels of low molecular weight metabolites also differ between men and women in circulating amino acids, lipids and carbohydrates and within brain tissue. While investigating the metabolism of blue crab tissues using Phosphorus-31 Nuclear Magnetic Resonance, we discovered that only the male blue crab (Callinectes sapidus) contained a phosphorus compound with a chemical shift well separated from the expected phosphate compounds. Spectra obtained from male gills were readily differentiated from female gill spectra. Analysis from six years of data from male and female crabs documented that the sex-specificity of this metabolite was normal for this species. Microscopic analysis of male and female gills found no differences in their gill anatomy or the presence of parasites or bacteria that might produce this phosphorus compound. Analysis of a rare gynandromorph blue crab (laterally, half male and half female) proved that this sex-specificity was an intrinsic biochemical process and was not caused by any variations in the diet or habitat of male versus female crabs. The existence of a sex-specific metabolite is a previously unrecognized, but potentially significant biochemical phenomenon. An entire enzyme system has been synthesized and activated only in one sex. Unless blue crabs are a unique species, sex-specific metabolites are likely to be present in other animals. Would the presence or absence of a sex-specific metabolite affect an animal's development, anatomy and biochemistry
Lethal Antibody Enhancement of Dengue Disease in Mice Is Prevented by Fc Modification
Immunity to one of the four dengue virus (DV) serotypes can increase disease severity in humans upon subsequent infection with another DV serotype. Serotype cross-reactive antibodies facilitate DV infection of myeloid cells in vitro by promoting virus entry via FcÎł receptors (FcÎłR), a process known as antibody-dependent enhancement (ADE). However, despite decades of investigation, no in vivo model for antibody enhancement of dengue disease severity has been described. Analogous to human infants who receive anti-DV antibodies by transplacental transfer and develop severe dengue disease during primary infection, we show here that passive administration of anti-DV antibodies is sufficient to enhance DV infection and disease in mice using both mouse-adapted and clinical DV isolates. Antibody-enhanced lethal disease featured many of the hallmarks of severe dengue disease in humans, including thrombocytopenia, vascular leakage, elevated serum cytokine levels, and increased systemic viral burden in serum and tissue phagocytes. Passive transfer of a high dose of serotype-specific antibodies eliminated viremia, but lower doses of these antibodies or cross-reactive polyclonal or monoclonal antibodies all enhanced disease in vivo even when antibody levels were neutralizing in vitro. In contrast, a genetically engineered antibody variant (E60-N297Q) that cannot bind FcÎłR exhibited prophylactic and therapeutic efficacy against ADE-induced lethal challenge. These observations provide insight into the pathogenesis of antibody-enhanced dengue disease and identify a novel strategy for the design of therapeutic antibodies against dengue
Chlamydia trachomatis Incidence and Re-Infection among Young Women â Behavioural and Microbiological Characteristics
This study aimed to estimate rates of chlamydia incidence and re-infection and to investigate the dynamics of chlamydia organism load in prevalent, incident and re-infections among young Australian women.1,116 women aged 16 to 25 years were recruited from primary care clinics in Australia. Vaginal swabs were collected at 3 to 6 month intervals for chlamydia testing. Chlamydia organism load was measured by quantitative PCR.There were 47 incident cases of chlamydia diagnosed and 1,056.34 person years of follow up with a rate of 4.4 per 100 person years (95% CI: 3.3, 5.9). Incident infection was associated with being aged 16 to 20 years [RRâ=â3.7 (95%CI: 1.9, 7.1)], being employed [RRâ=â2.4 (95%CI: 1.1, 4.9)] and having two or more new sex partners [RRâ=â5.5 (95%CI: 2.6, 11.7)]. Recent antibiotic use was associated with a reduced incidence [RR:0.1 (95%CI: 0.0, 0.5)]. There were 14 re-infections with a rate of 22.3 per 100 person years (95%CI: 13.2, 37.6). The median time to re-infection was 4.6 months. Organism load was higher for prevalent than incident infections (p<0.01) and for prevalent than re-infections (p<0.01).Chlamydia is common among young women and a high proportion of women are re-infected within a short period of time, highlighting the need for effective partner treatment and repeat testing. The difference in organism load between prevalent and incident infections suggests prevalent infection may be more important for ongoing transmission of chlamydia
Review article: Use of ultrasound in the developing world
As portability and durability improve, bedside, clinician-performed ultrasound is seeing increasing use in rural, underdeveloped parts of the world. Physicians, nurses and medical officers have demonstrated the ability to perform and interpret a large variety of ultrasound exams, and a growing body of literature supports the use of point-of-care ultrasound in developing nations. We review, by region, the existing literature in support of ultrasound use in the developing world and training guidelines currently in use, and highlight indications for emergency ultrasound in the developing world. We suggest future directions for bedside ultrasound use and research to improve diagnostic capacity and patient care in the most remote areas of the globe
Algal mats transport diaspores and carpological remains in shallow lakes
Algal mats in lakes and reservoirs can transport diaspores and carpological remains of plants, and thus may influence the creation of taphocoenoses. In 2012, I quantified carpological remains in two types of algal mats from a small reservoir in southern Poland. Mats formed by filamentous algae participate primarily in the original transport of diaspores, and can influence their concentration and facilitate their migration, mainly between the shores of the reservoir. Diatom mats partake primarily in diaspore redeposition, but can also cause their dispersal between the shore zone and the central part of the reservoir. This research demonstrates that mats built by diatoms contain far more remains and are more biologically diverse than filamentous algal mats. Movement of carpological remains observed in both types of algal mats points to their role in the formation of taphocoenoses and suggests that algal mats must be considered when interpreting macrofossil records
International Consensus Statement on Rhinology and Allergy: Rhinosinusitis
Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICARâRS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICARâRSâ2021 as well as updates to the original 140 topics. This executive summary consolidates the evidenceâbased findings of the document. Methods: ICARâRS presents over 180 topics in the forms of evidenceâbased reviews with recommendations (EBRRs), evidenceâbased reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICARâRSâ2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidenceâbased management algorithm is provided. Conclusion: This ICARâRSâ2021 executive summary provides a compilation of the evidenceâbased recommendations for medical and surgical treatment of the most common forms of RS
Evaluation of commercially available data systems for chromatography
Dit rapport beschrijft een systematische, flexibele, methode voor de keuze van chromatografie datasystemen (CDS). De methode is opgebouwd uit twee onderdelen: het verzamelen en waarderen van specificaties en het testen van de apparatuur met behulp van een chromatogram-simulator. De methode is tot stand gekomen door de inspanning van een hiervoor opgerichte RIVM werkgroep Chromatografie Dataverwerking en toegepast op achttien in 1986-1988 in Nederland commercieel verkrijgbare meerkanaals chromatografie dataverwerkingssystemen. De gepresenteerde resultaten kunnen gebruikt worden voor de keuze van een CDS op grond van voor een bepaald laboratorium geldende criteria. Tevens biedt het onderzoek de mogelijkheid tot objectieve vergelijking van de resultaten met die van nieuw op de markt komende apparatuur.Abstract not availableRIV
Registration system for chemical products/dangerous substances - definition study
In het kader van sectorplan 1994 is het bestaande registratiesysteem voor chemicalien geinventariseerd. Deze inventarisatie leverde een beschrijving op van negen systemen, twee handmatige en zeven geautomatiseerde. Vervolgens is een nieuwe opzet voor de registratie van chemische produkten gedefinieerd. De functionele en technische aspecten van het gedefinieerde Registratiesysteem Chemische Produkten/Gevaarlijke stoffen worden beschreven tot op (ongeveer) het niveau van een basisontwerp. Het betreft een systeem, dat in belangrijke mate beschouwd kan worden als de som van de huidige registratiesystemen voor chemische produkten in de sector, aangevuld met aspecten die voortvloeien uit het Veiligheidsbesluit fabrieken of werkplaatsen (VBF) en het Besluit kankerverwekkende stoffen en processen van de Arbo-wet. Naast het aspect gevaarlijke stoffen (registratie van gevaren, veiligheidsadviezen en carcinogene aspecten), kent het systeem functies op het gebied van o.a. de registratie van identificerende gegevens (namen, synoniemen, CAS nummers, chemische structuren, produktspecificaties, e.d.), logistiek (afhandeling bestelaanvragen en bestellingen, voorraadbewaking, registratie van opslag, gebruik en afvoer), kwaliteitsbewaking (registratie produktcontroles, bepaling en bewaking expiratiedata) en het leveren van de vereiste gegevens in het kader van de Hinderwet en de Wet Verontreiniging Oppervlaktewateren (WVO). Het systeem is geschikt voor de registratie van zowel produkten, die van buiten het laboratorium betrokken worden, als produkten die binnen het laboratorium bereid zijn, zoals standaardoplossingen. Wat de technische realisatie betreft, wordt voorgesteld het systeem als een client-server systeem te implementeren op basis van Oracle CDE, de standaard voor RIVM-brede database applicaties. De gebruiker van het systeem beschikt in deze situatie over een (client) applicatie op een Windows of Macintosh personal computer waarmee, via het RIVM netwerk, de (Oracle) database voor chemische produkten van het eigen of een andere laboratorium kan worden benaderd. Een mogelijke uitwerking van de belangrijke functies van het systeem wordt geillustreerd aan de hand van een visuele impressie van een prototype van het systeem.A laboratory system for the registration of chemical products, complying with the legislative regulations involving the use of dangerous substances, is defined. The functionality of the system covers the areas of registration of identifying data (names, synonyms, CAS Registry numbers, chemical structures), logistics (orders, stock control, storage, use, removal), quality control (product inspections, expiration), safety (risk descriptions, safety recommendations, carcinogenic aspects) and environmental protection. Technically, the system is defined as a client-server database application built with Oracle CDE, using Windows and Macintosh personal computers as clients. A possible implementation of the most important functions of the system is illustrated by a visual impression of a prototype of the system.RIV
- âŠ