Contrast Leakage Patterns from Dynamic Susceptibility Contrast Perfusion MRI in the Grading of Primary Pediatric Brain Tumors

BACKGROUND AND PURPOSE: The pattern of contrast leakage from DSC tissue signal intensity time curves have shown utility in distinguishing adult brain neoplasms, but has limited description in the literature for pediatric brain tumors. The purpose of this study is to evaluate the utility of grading pediatric brain tumors with this technique. MATERIALS AND METHODS: A retrospective review of tissue signal-intensity time curves from 63 pediatric brain tumors with preoperative DSC perfusion MR imaging was performed independently by 2 neuroradiologists. Tissue signal-intensity time curves were generated from ROIs placed in the highest perceived tumor relative CBV. The postbolus portion of the curve was independently classified as returning to baseline, continuing above baseline (T1-dominant contrast leakage), or failing to return to baseline (T2*-dominant contrast leakage). Interobserver agreement of curve classification was evaluated by using the Cohen κ. A consensus classification of curve type was obtained in discrepant cases, and the consensus classification was compared with tumor histology and World Health Organization grade. RESULTS: Tissue signal-intensity time curve classification concordance was 0.69 (95% CI, 0.54–0.84) overall and 0.79 (95% CI, 0.59–0.91) for a T1-dominant contrast leakage pattern. Twenty-five of 25 tumors with consensus T1-dominant contrast leakage were low-grade (positive predictive value, 1.0; 95% CI, 0.83–1.00). By comparison, tumors with consensus T2*-dominant contrast leakage or return to baseline were predominantly high-grade (10/15 and 15/23, respectively) with a high negative predictive value (1.0; 95% CI, 0.83–1.0). For pilomyxoid or pilocytic astrocytomas, a T1-dominant leak demonstrated high sensitivity (0.91; 95% CI, 0.70–0.98) and specificity (0.90, 95% CI, 0.75–0.97). CONCLUSIONS: There was good interobserver agreement in the classification of DSC perfusion tissue signal-intensity time curves for pediatric brain tumors, particularly for T1-dominant leakage. Among patients with pediatric brain tumors, a T1-dominant leakage pattern is highly specific for a low-grade tumor and demonstrates high sensitivity and specificity for pilocytic or pilomyxoid astrocytomas

Herpes Simplex Virus 1 and Chlamydophila (Chlamydia) pneumoniae promote Ab 1-42 amyloid processing in murine astrocytes linking an infectious process to Alzheimer\u27s disease

Background: Several studies have suggested an infectious etiology for Alzheimer\u27s disease (AD). Previously, our laboratory identified Chlamydia pneumoniae (Cpn) from autopsied sporadic AD brains, as well as developed a BALB/c mouse model that demonstrated infection-induced amyloid plaques similar to those found in AD. Hypothesis: We propose that an additional pathogen such as herpes simplex virus type 1 (HSV1), also may be a contributing factor in toin the pathology seen in AD. HSV1, in addition to Cpn, may be triggering the abnormal cleavage of the beta amyloid precursor protein (bAPP) into Ab1-42 , thereby contributing to amyloid plaque formation. Our current study examines amyloid processing following infection of primary and C8-DIA murine astrocytes with Cpn and HSV1. Materials and Methods: Immunocytochemistry and western analysis was used to analyze the outcome of infection by these two pathogens. Results: Cpn infection resulted in an increase in cytoplasmic labeling of Ab 1-42 relative to uninfected cells, while increased nuclear labeling of Ab 1-42 was observed following HSV1 infection. Co-infections with Cpn and HSV1 resulted in amyloid labeling resembling that of HSV1 infection alone, though Ab 1-42 labeling appeared decreased specifically in Cpn-infected cells of the co-infected monolayers. Conclusions: These data suggest that infection of astrocytic cells by HSV1 and (Cpn) alter the processing of bAPP, thereby producing Ab1-42. Therefore, these studies, inaddition to the previous research reported by our laboratory, support an emerging linkage of the infectious processs to the neuropathology characteristic of Alzheimer\u27s disease.https://digitalcommons.pcom.edu/posters/1008/thumbnail.jp

Graphene-based photovoltaic cells for near-field thermal energy conversion

Thermophotovoltaic devices are energy-conversion systems generating an electric current from the thermal photons radiated by a hot body. In far field, the efficiency of these systems is limited by the thermodynamic Schockley-Queisser limit corresponding to the case where the source is a black body. On the other hand, in near field, the heat flux which can be transferred to a photovoltaic cell can be several orders of magnitude larger because of the contribution of evanescent photons. This is particularly true when the source supports surface polaritons. Unfortunately, in the infrared where these systems operate, the mismatch between the surface-mode frequency and the semiconductor gap reduces drastically the potential of this technology. Here we show that graphene-based hybrid photovoltaic cells can significantly enhance the generated power paving the way to a promising technology for an intensive production of electricity from waste heat.Comment: 5 pages, 4 figure

INTERACTION OF THE DRY MATTER ON CONTENTS OF BIOGAS PRODUCED FROM PIG MANURE

Korištenje svinjske gnojovke kao biomase za proizvodnju bioplina jedan je od načina za učinkovitu uporabu otpada uz minimalan utjecaj na okoliš. Prednost bioplina i biomase u odnosu na fosilna goriva je neusporedivo manje emisije štetnih plinova i otpadnih tvari. Opterećenje atmosfere ugljik dioksidom (CO2) pri korištenju biomase je zanemarivo, jer je količina emitiranog CO2 prilikom izgaranja jednaka količini apsorbiranog CO2 tijekom rasta biljaka. Materijal istraživanja je svinjska gnojovka sa farme u okolici Osijeka gdje su svinje držane na rešetkastom podu a u istraživanju koristila se standardna metoda i kvantitativni postupak. Na uzorku se ispitivao postotak suhe tvari (ST) i njegova ovisnost o količini nastalog bioplina različitog sastava. Količina (ST) je niska i teoretski se kreće se od 0,5 do 10 %. Ona je varijabilna i ovisi o pasmini, hranidbi, uvjetima držanja, tehnologiji, izgnojavanju itd. Uzorak sa niskom količinom (ST) sadržavao je veliku količinu pepela te je njegov postotak iznosio više od 50 %. Većina uzoraka s najvećim postotkom suhe tvari imala je visoki postotak (iznad 70 %) hlapljive organanske tvari (OT). Udio dušika (N) i CO2 viši je u bioplinu proizvedenom iz svinjske gnojovke s većim udjelom ST. Količina N obrnuto je proporcionalna količini metana (CH4) /r=-0,948; p<0,001/. Dokazana je visoko pozitivna korelacija između koncentracije ST i količine bioplina (r = 0,947, p<0,001). Količina bioplina ovisi o sadržaju ST s posebnim naglaskom na visoki postotak OT. Koncentracija CH4 najveća je kod skupine s najnižom proizvodnjom bioplina. Što je veći sadržaj suhe OT i udio masti u supstratu, veći je i postotak CH4.Taking advantage of pig manure as biomass for production of biogas, is one of the ways of efficient use of waste with minimum interaction with the environment. Biogas and biomass oposite on fossil fuels has less emission of harmfull gasses and wastage rate. Emissions of carbon dioxide (CO2) in biomass, as a fuels, become from burning out is almost equal with amoung of apsorpted CO2 during growth of plants. Material from investigation was pig manure from a farm near Osijek, where all the pigs were kept on latticed floor. Methods of investigation were quantitative procedure with standard methods. On pig manure was investigated percent of dry matter (DM) and her correlation on amount of biogas with different composition. Amount of (DM) is low and teoreticaly between 0,5- 10 %. Results are variable and depends on rase, nutrition, handeling conditions, technology... The sample with low (DM) had high amount of ash > 50 % mineral part and high amount of (DM) had > 70 % dry organic matter (DOM). Higher amount of (DM) represents nutritive base for microorganisms with growing faster and produce more methane (CH4). High amount of (DM) gave high percentage of nitrogen N and CO2. Amount of N was in inverse proportion to the amount of CH4 (r=-0,948; p<0,001). Highly positive correlation was determined between (DM) on special accent on (DOM) and biogas amount (r = 0,947, p<0,001). Methane concentration was the highest in the group with the lowest biogas production. Higher content the (DOM) and the share of has positive correlation with fat in pig manure and gave high percentage of CH4

INTERACTION OF THE DRY MATTER ON CONTENTS OF BIOGAS PRODUCED FROM PIG MANURE

Korištenje svinjske gnojovke kao biomase za proizvodnju bioplina jedan je od načina za učinkovitu uporabu otpada uz minimalan utjecaj na okoliš. Prednost bioplina i biomase u odnosu na fosilna goriva je neusporedivo manje emisije štetnih plinova i otpadnih tvari. Opterećenje atmosfere ugljik dioksidom (CO2) pri korištenju biomase je zanemarivo, jer je količina emitiranog CO2 prilikom izgaranja jednaka količini apsorbiranog CO2 tijekom rasta biljaka. Materijal istraživanja je svinjska gnojovka sa farme u okolici Osijeka gdje su svinje držane na rešetkastom podu a u istraživanju koristila se standardna metoda i kvantitativni postupak. Na uzorku se ispitivao postotak suhe tvari (ST) i njegova ovisnost o količini nastalog bioplina različitog sastava. Količina (ST) je niska i teoretski se kreće se od 0,5 do 10 %. Ona je varijabilna i ovisi o pasmini, hranidbi, uvjetima držanja, tehnologiji, izgnojavanju itd. Uzorak sa niskom količinom (ST) sadržavao je veliku količinu pepela te je njegov postotak iznosio više od 50 %. Većina uzoraka s najvećim postotkom suhe tvari imala je visoki postotak (iznad 70 %) hlapljive organanske tvari (OT). Udio dušika (N) i CO2 viši je u bioplinu proizvedenom iz svinjske gnojovke s većim udjelom ST. Količina N obrnuto je proporcionalna količini metana (CH4) /r=-0,948; p<0,001/. Dokazana je visoko pozitivna korelacija između koncentracije ST i količine bioplina (r = 0,947, p<0,001). Količina bioplina ovisi o sadržaju ST s posebnim naglaskom na visoki postotak OT. Koncentracija CH4 najveća je kod skupine s najnižom proizvodnjom bioplina. Što je veći sadržaj suhe OT i udio masti u supstratu, veći je i postotak CH4.Taking advantage of pig manure as biomass for production of biogas, is one of the ways of efficient use of waste with minimum interaction with the environment. Biogas and biomass oposite on fossil fuels has less emission of harmfull gasses and wastage rate. Emissions of carbon dioxide (CO2) in biomass, as a fuels, become from burning out is almost equal with amoung of apsorpted CO2 during growth of plants. Material from investigation was pig manure from a farm near Osijek, where all the pigs were kept on latticed floor. Methods of investigation were quantitative procedure with standard methods. On pig manure was investigated percent of dry matter (DM) and her correlation on amount of biogas with different composition. Amount of (DM) is low and teoreticaly between 0,5- 10 %. Results are variable and depends on rase, nutrition, handeling conditions, technology... The sample with low (DM) had high amount of ash > 50 % mineral part and high amount of (DM) had > 70 % dry organic matter (DOM). Higher amount of (DM) represents nutritive base for microorganisms with growing faster and produce more methane (CH4). High amount of (DM) gave high percentage of nitrogen N and CO2. Amount of N was in inverse proportion to the amount of CH4 (r=-0,948; p<0,001). Highly positive correlation was determined between (DM) on special accent on (DOM) and biogas amount (r = 0,947, p<0,001). Methane concentration was the highest in the group with the lowest biogas production. Higher content the (DOM) and the share of has positive correlation with fat in pig manure and gave high percentage of CH4

Study of a Nonlocal Density scheme for electronic--structure calculations

An exchange-correlation energy functional beyond the local density approximation, based on the exchange-correlation kernel of the homogeneous electron gas and originally introduced by Kohn and Sham, is considered for electronic structure calculations of semiconductors and atoms. Calculations are carried out for diamond, silicon, silicon carbide and gallium arsenide. The lattice constants and gaps show a small improvement with respect to the LDA results. However, the corresponding corrections to the total energy of the isolated atoms are not large enough to yield a substantial improvement for the cohesive energy of solids, which remains hence overestimated as in the LDA.Comment: 4 postscript figure

Evidence of early multi-strange hadron freeze-out in high energy nuclear collisions

Recently reported transverse momentum distributions of strange hadrons produced in Pb(158AGeV) on Pb collisions and corresponding results from the relativistic quantum molecular dynamics (RQMD) approach are examined. We argue that the experimental observations favor a scenario in which multi-strange hadrons are formed and decouple from the system rather early at large energy densities (around 1 GeV/fm$^3$). The systematics of the strange and non-strange particle spectra indicate that the observed transverse flow develops mainly in the late hadronic stages of these reactions.Comment: 4 pages, 4 figure

Skyrmions and edge spin excitations in quantum Hall droplets

We present an analysis of spin-textures in Quantum Hall droplets, for filling factors $\nu \simeq 1$. Analytical wavefunctions with well defined quantum numbers are given for the low-lying states of the system which result to be either bulk skyrmions or edge spin excitations. We compute dispersion relations and study how skyrmions become ground states of the Quantum Hall droplet at $\nu \gtrsim 1$. A Hartree-Fock approximation is recovered and discussed for those spin textures.Comment: RevTeX, four postscript figures appende

Improved understanding of dynamic water and mass budgets of high‐alpine karst systems obtained from studying a well‐defined catchment area

Large areas of Europe, especially in the Alps, are covered by carbonate rocks and in many alpine regions, karst springs are important sources for drinking water supply. Because of their high variability and heterogeneity, the understanding of the hydrogeological functioning of karst aquifers is of particular importance for their protection and utilisation. Climate change and heavy rainfall events are major challenges in managing alpine karst aquifers which possess an enormous potential for future drinking water supply. In this study, we present research from a high‐alpine karst system in the UNESCO Biosphere Reserve Großes Walsertal in Austria, which has a clearly defined catchment and is drained by only one spring system. Results show that (a) the investigated system is a highly dynamic karst aquifer with distinct reactions to rainfall events in discharge and electrical conductivity; (b) the estimated transient atmospheric CO2 sink is about 270 t/a; (c) the calculated carbonate rock denudation rate is between 23 and 47 mm/1000a and (d) the rainfall‐discharge behaviour and the internal flow dynamics can be successfully simulated using the modelling package KarstMod. The modelling results indicate the relevance of matrix storage in determining the discharge behaviour of the spring, particularly during low‐flow periods. This research and the consequent results can contribute and initiate a better understanding and management of alpine karst aquifers considering climate change with more heavy rainfall events and also longer dry periods.The investigated karst system contributes to the transient atmospheric CO2 sink with about 270 t/a. Carbonate denudation rates vary between 23 and 47 mm/1000a. Rainfall‐discharge modelling results indicate the importance of matrix storage particularly during low‐flow periods. imageBundesministerium für Bildung und Forschung http://dx.doi.org/10.13039/501100002347FP7 People: Marie‐Curie Actions http://dx.doi.org/10.13039/10001126

Soybean Straw, Corn Stover and Sunflower Stalk as Possible Substrates for Biogas Production in Croatia: A Review

Biomass availability is one of the key factors for biogas production in the future. The current status and possibilities for utilizing harvest residues (soybean straw, corn stover and sunflower stalk) in Croatia for biogas production is given. In the last few decades, different pretreatment methods have been developed for the degradation of different lignocellulosic biomass, but many of them are environmentally unfriendly and sometimes very expensive. More research and development is necessary in order to find both economically and environmentally friendly pretreatment methods. This paper provides a review on the mechanical, physical, and biological methods used for different lignocellulose material pretreatment. Harvest residues are usually left in the field, but with the improvement of the pretreatment process along with soil protection, they could be used for the production of huge amounts of energy in the future. This work is licensed under a Creative Commons Attribution 4.0 International License