Gamma Ray Glow Observations at 20-km Altitude.

In the spring of 2017 an ER-2 aircraft campaign was undertaken over continental United States to observe energetic radiation from thunderstorms and lightning. The payload consisted of a suite of instruments designed to detect optical signals, electric fields, and gamma rays from lightning. Starting from Georgia, USA, 16 flights were performed, for a total of about 70 flight hours at a cruise altitude of 20 km. Of these, 45 flight hours were over thunderstorm regions. An analysis of two gamma ray glow events that were observed over Colorado at 21:47 UT on 8 May 2017 is presented. We explore the charge structure of the cloud system, as well as possible mechanisms that can produce the gamma ray glows. The thundercloud system we passed during the gamma ray glow observation had strong convection in the core of the cloud system. Electric field measurements combined with radar and radio measurements suggest an inverted charge structure, with an upper negative charge layer and a lower positive charge layer. Based on modeling results, we were not able to unambiguously determine the production mechanism. Possible mechanisms are either an enhancement of cosmic background locally (above or below 20 km) by an electric field below the local threshold or an enhancement of the cosmic background inside the cloud but then with normal polarity and an electric field well above the Relativistic Runaway Electron Avalanche threshold.

A role for miR-132 in learned safety.

Learned safety is a fear inhibitory mechanism, which regulates fear responses, promotes episodes of safety and generates positive affective states. Despite its potential as experimental model for several psychiatric illnesses, including post-traumatic stress disorder and depression, the molecular mechanisms of learned safety remain poorly understood, We here investigated the molecular mediators of learned safety, focusing on the characterization of miRNA expression in the basolateral amygdala (BLA). Comparing levels of 22 miRNAs in learned safety and learned fear trained mice, six safety-related miRNAs, including three members of the miR-132/-212 family, were identified. A gain-of-function approach based upon in-vivo transfection of a specific miRNA mimic, and miR-132/212 knock-out mice as loss-of-function tool were used in order to determine the relevance of miR-132 for learned safety at the behavioral and the neuronal functional levels. Using a designated bioinformatic approach, PTEN and GAT1 were identified as potential novel miR-132 target genes and further experimentally validated. We here firstly provide evidence for a regulation of amygdala miRNA expression in learned safety and propose miR-132 as signature molecule to be considered in future preclinical and translational approaches testing the transdiagnostic relevance of learned safety as intermediate phenotype in fear and stress-related disorders.

Optimizing and extending light-sculpting microscopy for fast functional imaging in neuroscience.

A number of questions in system biology such as understanding how dynamics of neuronal networks are related to brain function require the ability to capture the functional dynamics of large cellular populations at high speed. Recently, this has driven the development of a number of parallel and high speed imaging techniques such as light-sculpting microscopy, which has been used to capture neuronal dynamics at the whole brain and single cell level in small model organisms. However, the broader applicability of light-sculpting microcopy is limited by the size of volumes for which high speed imaging can be obtained and scattering in brain tissue. Here, we present strategies for optimizing the present tradeoffs in light-sculpting microscopy. Various scanning modalities in light-sculpting microscopy are theoretically and experimentally evaluated, and strategies to maximize the obtainable volume speeds, and depth penetration in brain tissue using different laser systems are provided. Design-choices, important parameters and their trade-offs are experimentally demonstrated by performing calcium-imaging in acute mouse-brain slices. We further show that synchronization of line-scanning techniques with rolling-shutter read-out of the camera can reduce scattering effects and enhance image contrast at depth.

A validated analytical method for the determination of perfluorinated compounds in surface-, sea- and sewagewater using liquid chromatography coupled to time-of-flight mass spectrometry.

Perfluorinated compounds (PFCs), which are extensively used in a wide variety of applications because of their specific surfactant properties, have recently appeared as an important new class of global environmental pollutants. Quantitative analysis of PFCs in aqueous matrices remains, however, a challenging task. During this study, a new analytical method for the determination of 14 PFCs in surface-, sewage- and seawater was developed and validated. The target analytes were extracted using solid-phase extraction followed by liquid chromatography coupled to a time-of-flight mass spectrometer (LC-ToF-MS). The use of very narrow mass tolerance windows (< 10 ppm) resulted in a highly selective MS-technique for the detection of PFCs in complex aqueous matrices. Validation of this analytical method in surface-, sewage- and seawater resulted in limits of quantification (LOQs) varying from 2 to 200 ng L⁻¹, satisfying recoveries (92-134%), and good linearity (R²=0.99 for most analytes). Analysis of samples of the North Sea, the Scheldt estuary, and three harbours of the Belgian coastal region led to the detection of four different PFCs. Perfluorooctane sulfonate (PFOS) was found to be the most abundant PFC in levels up to 38.9 ng L⁻¹.

Fractional magnetization plateaus and magnetic order in the Shastry-Sutherland magnet TmB4.

We investigate the phase diagram of TmB4, an Ising magnet on a frustrated Shastry-Sutherland lattice, by neutron diffraction and magnetization experiments. At low temperature we find Néel order at low field, ferrimagnetic order at high field, and an intermediate phase with magnetization plateaus at fractional values M/M_(sat)=1/7,1/8,1/9,... and spatial stripe structures. Using an effective S=1/2 model and its equivalent two-dimensional fermion gas we suggest that the magnetic properties of TmB4 are related to the fractional quantum Hall effect of a 2D electron gas.

Pesticides in rainwater in Flanders, Belgium: results from the monitoring program 1997-2001.

In 1997 the Flemish Environmental Agency (FEA) started a monitoring program "Pesticides in Rain in Flanders, Belgium". The original purpose of the monitoring program was to examine the possible occurrence of dichlorvos in rainwater and subsequent deposition. However, it was thought necessary from the beginning to monitor a wide range of pesticides. During the first year some 62 pesticides and metabolites and 9 polychlorinated biphenyls, were monitored at 4 locations. Nowadays the monitoring program has grown up to more than 100 pesticides and metabolites and 11 polychlorinated biphenyls examined at 8 different locations. Rainwater is collected continuously and samples are examined for pesticides and PCB's on a weekly basis. In agreement with other European studies pesticides are found in rainwater samples during times of application. Pesticides which are most frequently detected are [small alpha]-, [small beta]-endosulfan and endosulfan sulfate, [gamma]-HCH (lindane), dichlorvos, atrazine, diuron, DNOC, glyphosate and AMPA and isoproturon. Furthermore it was seen that most pesticides showed a deposition pattern related to local spraying operations.

Identification of hepatic transcriptional changes in insulin-resistant rats treated with peroxisome proliferator activated receptor-alpha agonists.

Peroxisome proliferator activated receptor (PPAR)-alpha controls the expression of multiple genes involved in lipid metabolism, and activators of PPAR-alpha, such as fibrates, are commonly used drugs in the treatment of hypertriglyceridemia and other dyslipidemic states. Recent data have also suggested a role for PPAR-alpha in insulin resistance and glucose homeostasis. In the present study, we have assessed the transcriptional and physiological responses to PPAR-alpha activation in a diet-induced rat model of insulin resistance. The two PPAR-alpha activators, fenofibrate and Wy-14643, were dosed at different concentrations in high-fat fed Sprague-Dawley rats, and the transcriptional responses were examined in liver using cDNA microarrays. In these analyses, 98 genes were identified as being regulated by both compounds. From this pool of genes, 27 correlated to the observed effect on plasma insulin, including PPAR-alpha itself and the leukocyte antigen-related protein tyrosine phosphatase (PTP-LAR). PTP-LAR was downregulated by both compounds, and showed upregulation as a result of the high-fat feeding. This regulation was also observed at the protein level. Furthermore, downregulation of PTP-LAR by fenofibric acid was demonstrated in rat FaO hepatoma cells in vitro, indicating that the observed regulation of PTP-LAR by fenofibrate and Wy-14643 in vivo is mediated as a direct effect of the PPAR agonists on the hepatocytes. PTP-LAR is one of the first genes involved in insulin receptor signaling to be shown to be regulated by PPAR-alpha agonists. These data suggest that factors apart from skeletal muscle lipid supply may influence PPAR-alpha-mediated amelioration of insulin resistance.

Changes of immunological parameters in immunocompromised patients under selective decontamination of the digestive tract. Second Part: Investigations on the influence of drugs on zymosan-induced and luminol-enhanced chemiluminescence of peripheral leucocytes.

The influence of drugs used for selective decontamination, given in therapeutically effective concentrations, was examined in healthy controls and immunocompromised patients with hematologic systemic diseases by measuring the zymosan-induced and luminol-enhanced chemiluminescence of peripheral leucocytes. Drug-induced repression of phagocytic activity could usually be found both in healthy controls and in patients with hematologic systemic diseases. The combination of trimethoprim and sulfamerazine had a pronounced repressive effect. Such indications should be taken as a basis for further investigations in order to avoid additional iatrogenic restriction of defence. If possible, drugs with effects leading to repression of phagocytosis should not be used for selective decontamination.

Changes of immunological parameters in immunocompromised patients under selective decontamination of the digestive tract. Third Part: Behaviour of some plasma proteins.

We studied the importance of changes in plasma protein concentrations in patients with hematologic systemic diseases treated by selective decontamination of the digestive tract. The concentrations of albumin, acute-phase proteins, immunoglobulins and fibronectin were determined by laser nephelometry in 125 serum samples of eight patients. Results obtained allow the following conclusions: 1. There was a correlation between the clinical condition and concentrations of acid alpha-1-glycoprotein, IgG, CRP and fibronectin. These concentrations might be important for assessment of the course of the disease, effectiveness of therapy and the detection of pathogenetic relations. 2. The acid alpha-1-glycoprotein is of particular importance since relations exist between changes in its concentration and therapeutic results as well as the prognosis of the disease.

[The laser nephelometric determination of C-reactive protein]. / Untersuchungen zur lasernephelometrischen Bestimmung des C-reaktiven Proteins.

A method for the laser nephelometric determination of C-reactive protein (CRP) is described, using easily available reagents. The upper limits of the reference ranges were determined for newborns and adults. They are 12 mg/l and 27 mg/l, respectively. A comparison with the radial immunodiffusion, which is a widespread method in the clinical laboratory, showed significantly different (higher) values for the laser nephelometry as well as a higher reliability in detecting only slightly raised concentrations. The capillary test proved to be not suitable for the quantification of CRP, but is sufficiently reliable for the detection of sera with pathologically elevated CRP-concentrations.

[Chemoluminescence study of the influence of phagocytosis of peripheral blood leukocytes using a perfluorocarbon-containing blood substitute]. / Chemolumineszenzuntersuchungen zur Beeinflussung der Phagozytose der Leukozyten des periphern Blutes durch perfluorcarbonhaltige Blutersatzmittel.

In an animal experimental model (rats) the influence of which model substances for blood substitution of GDR origin may have on the phagocytosis behaviour of leukocytes of the peripheral blood was investigated by means of luminol-amplified chemoluminescence. After applying the model substance in an amount corresponding to 10% of the circulating blood volume a reversible increase of luminol-amplified chemoluminescence could be observed. The values referred to the portion of neutrophilic granulocytes, however, showed no significant differences compared to the control groups. The opsonizing capacity of the serum towards cymosan revealed a temporary deficit after applying blood substitution substances of GDR origin. The conclusion is drawn that the functions of leukocytes of the peripheral blood recorded by the applied method are not depressed by the model substances used.

Changes of plasma fibronectin concentration and phagocytic activity in immunosuppressed patients during selective decontamination.

Plasma fibronectin and phagocytic activity play important roles in combating infections. The question is discussed, whether both defense systems are also of importance in immunosuppressed patients. Further, the behaviour of plasma fibronectin determined by laser nephelometry, and phagocytic activity determined by chemiluminescence is demonstrated in patients with leukaemia under the conditions of selective decontamination of the intestinal tract. The following results are shown: Plasma fibronectin concentration decreases 10 to 14 days before onset of the first clinical signs of an infection. Plasma fibronectin level changes appear earlier than that of C-reactive protein (Crp). Therefore, it is suitable as a parameter for assessment of the course of an infection. Decreased plasma fibronectin levels occurring over longer periods have to be regarded as unfavourable prognostic criterion. The phagocytic activity of immunosuppressed patients selectively decontaminated is significantly below that of healthy adults. A clear assignment of phagocytic activity to the clinical picture, the number of granulocytes and plasma fibronectin level is not possible at present. Additional studies are necessary. Both plasma fibronectin level and phagocytic activity do not appear to be influenced by selective decontamination of the intestinal tract.

[Early diagnosis of primary chronic glomerulonephritis in the latency stage]. / Frühdiagnostik primär chronischer Glomerulonephritiden im Stadium der Latenz.

In 74 of 195 patients with isolated proteinuria and/or haematuria investigated by means of renal biopsy laser-nephelometric determinations of the concentrations of albumin, alpha2-macroglobulin, transferrin, IgG, IgA and IgM in the urine were performed. Their result was that patients with chronic interstitial nephritis or chronic glomerulonephritis by increased concentration of albumin, transferrin, IgG and IgA statistically ascertained differ from patients with normal renal tissue or slight glomerular abnormalities.

[Methodologic references for clinical function diagnosis of glomerular permeability selectivity by molecular wight related protein analysis and additional para-aminohippuric acid load]. / Methodologische Hinweise zur klinischen Funktionsdiagnostik der glomerulären Permselektivität durch molekulargewichtsbezogene Proteinanalyse und zusätzlicher Paraamonohippursäure-Belastung.

Glomerular perm selectivity can be approximately estimated from the apparent glomerular protein clearance in terms of molecular weight since the relative protein clearance is approximately identical with the corresponding screen coefficient relation. Systematic relativization of individual protein clearances by reference to albumin (or transferrin) clearance requires the application of special calculations to find out the regression coefficients relevant to functional diagnosis. A PAH load influences tubular protein reabsorption so that the clearance of higher-molecular proteins (IgA alpha 2-macroglobuli, IgM) rises. Taking the changes in protein clearance under renotubular PAH load into account allows a more precise estimation of glomerular permeability to be made, in comparison with protein analyses not using PAH load.

Polycyclic aromatic hydrocarbons in rainwater.

A study on polycyclic aromatic hydrocarbons (PAH) in rainwater was carried out over periods of at least one year at two locations in Belgium with different environments. Maximum amounts and concentrations of PAH were reached during the winter period, mainly due to household heating. This influence was also reflected in the relative proportions of the six PAH measured. For comparable periods the amounts of PAH were almost proportional to the quantity of rain. With the available data, and as most of the rainfall is coming from the same wind direction, it was not feasible to localise possible pollution sources based upon the distribution of PAH over the different windsectors, nor was it possible to identify significant differences for both sampling locations due to their different surroundings, indicating that the rain plays an important role in the transport and distribution of pollutants over a wide area. Between about 100 and 170 micrograms m-2 PAH and 2 to 3 g m-2 of total organic carbon content (TOC) per year were deposited by the rain, corresponding to mean concentrations of about 140 ngl-1 of PAH and 2.9 mgl-1 of TOC.