Simultaneous flow cytometric detection of antibodies against platelets, granulocytes and lymphocytes

We present a time-saving and objective flow cytometric immunofluorescence assay for the simultaneous detection of antibodies against platelets, granulocytes or lymphocytes using a reconstituted mixture of these cell populations. Platelets, granulocytes and lymphocytes could be distinguished on the basis of their forward (FSC) and sideways (SSC) light scattering properties plotted on scales of 4 log orders. After setting FSC/SSC gates around the platelets, granulocytes and lymphocytes, the reactivity of the sera with the cell populations was determined by histogram analyses of immunofluorescence for each gate. The flow cytometric assay of reconstituted cell mixtures showed a strong, positive correlation with a reference microscopic immunofluorescence assay of separate cell suspensions. The reproducible procedures for the isolation and staining of the cells and the electronic stability of the flow cytometer permitted the use of the same gate and marker settings throughout the experiments. Consequently, the entire analysis of data stored in list mode could be performed using a keystroke, so that time consuming and subjective manual analyses were avoided

Post-mortem tissue biopsies obtained at minimally invasive autopsy: An RNA-quality analysis

Introduction: Bereaved relatives often refuse to give consent for post-mortem investigation of deceased cancer patients, mainly because of the mutilation due to conventional au

Emissieroutes van gewasbeschermingsmiddelen in de teelt van snijmaos in het zuidoosten van Noord-Brabant; interpretatie van meetgegevens uit het demonstratieproject 'Bewust boeren voor een schone Maas' in 1997

Voor het demonstratieproject `Bewust boeren voor een schone Maas' is gedurende 1997 een uitgebreid chemisch meetprogramma uitgevoerd bij drie snijmaospercelen in de omgeving van Someren (Noord-Brabant). Het programma had ten doel informatie te verkrijgen omtrent de belangrijkste emissieroutes van gewasbeschermingsmiddelen naar oppervlaktewater in de snijmaos. Voor de drie bestudeerde stoffen (metolachloor, atrazin en bromoxynil) speelden naast spuitdrift ook oppervlakkige afspoeling en transport via verwaaiing van gronddeeltjes een belangrijke rol bij de belasting van oppervlaktewater. Aanbevolen wordt om meer aandacht te besteden aan deze routes in het onderzoek en bij het ontwikkelen van beleid gericht op emissiereductie

Dutch Environmental Risk Indicator for Plant Protection Products

The NMI 3 focusses on indicators for emissions to surface water and the related aquatic risk resulting from agricultural use of pesticides in the Netherlands. The risk indicator is the exposure toxicity ratio. The model also considers the risk to groundwater, soil organisms and the terrestrial ecosystem. The model calculates indicators for emission to surface water resulting from atmospheric deposition, spray drift, drainage flow, point sources, discharge from greenhouses. The model combines a wide range of information about pesticide sales, usage, spray drift mitigation, emission factors, crop maps, surface water, soil, climate, and substance properties. The primary goal is to compare on a relative scale the annual risk at national scale at the starting and end year of the policy period. The results can be used for ranking, for comparing applications of similar type and for visualisation of spatial patterns of indicators. The result cannot be translated into a risk at a specific location and time

The stimulatory effect of albumin on luteinizing hormone-stimulated Leydig cell steroid production depends on its fatty acid content and correlates with conformational changes

__Abstract__ The effects of purified albumin species and albumin fragments (0.2–1% w/v) on short-term (4 h) steroid secretion by immature rat Leydig cells, in the presence of a maximally stimulating dose of luteinizing hormone (LH), were investigated. Human albumin and the peptic fragment (comprising residues 1–387) enhanced pregnenolone production in isolated rat Leydig cells, whereas chicken albumin and the tryptic fragment (comprising residues 198–585) were not active. This stimulatory effect of human albumin and the peptic fragment correlated with the potential of these proteins to undergo a pH-dependent neutral-to-base transition as measured by circular dichroism. The tryptic fragment and chicken albumin did not have the potential to undergo such a transition. The pH-dependent conformational changes of albumin and fragments thereof occurred in parallel with a change in the binding affinity for testosterone and pregnenolone. The fatty acid oleic acid and the drug suramin, only when present in a molar ligand-to-albumin ratio equal to or higher than 2, inhibited the albumin-mediated stimulation of steroid production. These data show that the stimulatory effects of albumin species on LH-induced Leydig cell pregnenolone production depend on their fatty acid content and correlate with the potential of these molecules to undergo conformational changes. It is unknown via which mechanisms albumin exerts its stimulatory effect, but the LH action through the cyclic AMP pathway seems not to be affected

The sign problem in Monte Carlo simulations of frustrated quantum spin systems

We discuss the sign problem arising in Monte Carlo simulations of frustrated quantum spin systems. We show that for a class of ``semi-frustrated'' systems (Heisenberg models with ferromagnetic couplings $J_z(r) < 0$ along the $z$-axis and antiferromagnetic couplings $J_{xy}(r)=-J_z(r)$ in the $xy$-plane, for arbitrary distances $r$) the sign problem present for algorithms operating in the $z$-basis can be solved within a recent ``operator-loop'' formulation of the stochastic series expansion method (a cluster algorithm for sampling the diagonal matrix elements of the power series expansion of ${\rm exp}(-\beta H)$ to all orders). The solution relies on identification of operator-loops which change the configuration sign when updated (``merons'') and is similar to the meron-cluster algorithm recently proposed by Chandrasekharan and Wiese for solving the sign problem for a class of fermion models (Phys. Rev. Lett. {\bf 83}, 3116 (1999)). Some important expectation values, e.g., the internal energy, can be evaluated in the subspace with no merons, where the weight function is positive definite. Calculations of other expectation values require sampling of configurations with only a small number of merons (typically zero or two), with an accompanying sign problem which is not serious. We also discuss problems which arise in applying the meron concept to more general quantum spin models with frustrated interactions.Comment: 13 pages, 16 figure

Attributable mortality of antibiotic resistance in Gram-negative infections in the Netherlands: a parallel matched cohort study

Abstract Objectives Antibiotic resistance in Gram-negative bacteria has been associated with increased mortality. This was demonstrated mostly for third-generation cephalosporin-resistant (3GC-R) Enterobacterales bacteraemia in international studies. Yet, the burden of resistance specifically in the Netherlands and created by all types of Gram-negative infection has not been quantified. We therefore investigated the attributable mortality of antibiotic resistance in Gram-negative infections in the Netherlands. Methods In eight hospitals, a sample of Gram-negative infections was identified between 2013 and 2016, and separated into resistant and susceptible infection cohorts. Both cohorts were matched 1:1 to non-infected control patients on hospital, length of stay at infection onset, and age. In this parallel matched cohort set-up, 30-day mortality was compared between infected and non-infected patients. The impact of resistance was then assessed by dividing the two separate risk ratios (RRs) for mortality attributable to Gram-negative infection. Results We identified 1,954 Gram-negative infections, of which 1,190 (61%) involved Escherichia coli, 210 (11%) Pseudomonas aeruginosa, and 758 (39%) bacteraemia. Resistant Gram-negatives caused 243 infections (12%; 189 (78%) 3GC-R Enterobacterales, 9 (4%) multidrug-resistant P. aeruginosa, no carbapenemase-producing Enterobacterales). Subsequently, we matched 1,941 non-infected controls. After adjustment, point estimates for RRs comparing mortality between infections and controls were similarly higher than 1 in case of resistant infections and susceptible infections (1.42 (95% confidence interval 0.66-3.09) and 1.32 (1.06-1.65), respectively). By dividing these, the RR reflecting attributable mortality of resistance was calculated as 1.08 (0.48-2.41). Conclusions In the Netherlands, antibiotic resistance did not increase 30-day mortality in Gram-negative infections

Review article: MHD wave propagation near coronal null points of magnetic fields

We present a comprehensive review of MHD wave behaviour in the neighbourhood of coronal null points: locations where the magnetic field, and hence the local Alfven speed, is zero. The behaviour of all three MHD wave modes, i.e. the Alfven wave and the fast and slow magnetoacoustic waves, has been investigated in the neighbourhood of 2D, 2.5D and (to a certain extent) 3D magnetic null points, for a variety of assumptions, configurations and geometries. In general, it is found that the fast magnetoacoustic wave behaviour is dictated by the Alfven-speed profile. In a $\beta=0$ plasma, the fast wave is focused towards the null point by a refraction effect and all the wave energy, and thus current density, accumulates close to the null point. Thus, null points will be locations for preferential heating by fast waves. Independently, the Alfven wave is found to propagate along magnetic fieldlines and is confined to the fieldlines it is generated on. As the wave approaches the null point, it spreads out due to the diverging fieldlines. Eventually, the Alfven wave accumulates along the separatrices (in 2D) or along the spine or fan-plane (in 3D). Hence, Alfven wave energy will be preferentially dissipated at these locations. It is clear that the magnetic field plays a fundamental role in the propagation and properties of MHD waves in the neighbourhood of coronal null points. This topic is a fundamental plasma process and results so far have also lead to critical insights into reconnection, mode-coupling, quasi-periodic pulsations and phase-mixing.Comment: 34 pages, 5 figures, invited review in Space Science Reviews => Note this is a 2011 paper, not a 2010 pape

Making Sense Through Participation

In this chapter we discuss the issue of social differences in relation to learning. In theories on co-operative learning or collaborative learning social differences are treated as characteristics of individual learners. The focus on learning as a social process is primarily elaborated in terms of interaction between pupils and the combined construction of knowledge. Sociocultural theory (Vygotsky, Lave & Wenger), however, understands ‘social’ not only in terms of knowledge/meaning being constructed in interaction with others, but also in terms of the cultural practices/activities informing these interaction processes. Learning can be understood as increasing participating in communities of practice. As social differences are an intrinsic part of the culture in which students are learning to participate, these are also an inherent aspect of learning processes in schools. Students learn to participate in practices in different ways, depending on their social position, and thus develop distinguished cultural identities. In this chapter we elaborate on this tenet, using examples from various empirical research projects on learning in secondary education. We not only show how social differences in the cultural practices that underpin learning influence what is learned by whom, but also explore the consequences of this perspective for the pedagogical space of the school