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2,395
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2,395 results for “Contrast”
Pathways underlying selective neuronal vulnerability in Alzheimer's disease: contrasting the vulnerable locus coeruleus to the resilient substantia nigra
GEO Series GSE273787. Homo sapiens. 44 samples. Type: Expression profiling by high throughput sequencing.
Assembly and annotation of Solanum dulcamara and Solanum nigrum plant genomes, two nightshades with contrasting susceptibilities to Ralstonia solanacearum
GEO Series GSE255584. Solanum nigrum. 1 samples. Type: Methylation profiling by high throughput sequencing; Other.
miRNAs expression in two soybean root with contrasting cadmium tolerance
GEO Series GSE50388. Glycine max. 4 samples. Type: Non-coding RNA profiling by array.
Contrasting in vitro and in vivo methanol oxidation activities of lanthanide-dependent alcohol dehydrogenases XoxF1 and ExaF from Methylobacterium extorquens AM1
GEO Series GSE125593. Methylorubrum extorquens AM1. 5 samples. Type: Expression profiling by high throughput sequencing.
Transcriptome analysis using RNA sequencing of three endemic Myrtaceae species from New Caledonia displaying contrasting responses to myrtle rust (Austropuccinia psidii) [ARIGU-EUCGR]
GEO Series GSE106736. Arillastrum gummiferum. 6 samples. Type: Expression profiling by high throughput sequencing.
Dataset:Slab rollback versus delamination: contrasting fates of flat subduction and implications for South China evolution in Mesozoic
<p>This dataset contains simulation results used for visualizing Figures in <br> “Slab rollback versus delamination: contrasting fates of flat subduction and implications for South China evolution in Mesozoic”</p>
Standardizing thermal contrast among local climate zones at a continental scale
<p>The seasonal daily mean, daytime mean and nighttime mean air temperature over China weather stations in 2016.</p> <p>Read "README.txt" for the details of the data</p>
Carbon dioxide and methane exchange of a patterned subarctic fen during two contrasting growing seasons [Data set]
<p>The data set contains carbon dioxide (CO<sub>2</sub>) and methane (CH<sub>4</sub>) fluxes on ecosystem and plant community level, and ancilliary meteorological and environmental data, measured at Kaamanen fen in Northern Finland (N69°8.435', E27°16.189', 155 m a.s.l.), during 2017 - 2018. Additionally, the data set contains soil data from the fen, forest and lake ecosystems in the catchment, measured by Juha Mikola.</p> <p>C_fluxes_Heiskanen_et_al.csv includes ecosystem scale quality screened, u* filtered and gap-filled eddy covariance flux data and plant community scale flux data modelled from manual flux chamber measurements.</p> <p>environmental_data1_Heiskanen_et_al.csv and environmental_data2_Heiskanen_et_al.csv include ancillary meteorological and environmental data.</p> <p>LAI_data_2017_Heiskanen_et_al.csv and LAI_data_2018_Heiskanen_et_al.csv include leaf area index data.</p> <p>UEF_data_with_LCTs.xlsx includes soil data from peatlands, mineral soils and lake sediments, by Juha Mikola.</p>
Reliability of 3D image analysis and influence of contrast medium administration on measurement of Hounsfield unit values of the proximal femur
<p>These datasets consists of three PDF files for intraobserver ICC, interobserver ICC and effect of contrast medium administration.</p>
Inhibitory rTMS Modulation of the Occipital Pole Decreases Cortical Suppression of Liminal Contrast Perception
<p>Matalb format data in data.mat.</p> <p>See dataCode.zip for details and example code (entire processing code not provided here).</p>
Evaluation of metronomic chemotherapy response using diffusion and dynamic contrast-enhanced MRI
Purpose: To investigate the feasibility of using diffusion MRI (dMRI) and dynamic contrast-enhanced (DCE) MRI to evaluate the treatment response of metronomic chemotherapy (MCT) in the 4T1 mammary tumor model of locally advanced breast cancer. Methods: Twelve Balb/c mice with metastatic breast cancer were divided into treated and untreated (control) groups. The treated group (n=6) received five treatments of anti-metabolite agent 5-Fluorouracil (5FU) in the span of two weeks. dMRI and DCE-MRI were acquired for both treated and control groups before and after MCT. Immunohistochemically staining and measurements were performed after the post-MRI measurements for comparison. Results: The control mice had significantly ( p <0.005) larger tumors than the MCT treated mice. The DCE-MRI analysis showed a decrease in contrast enhancement for the control group, whereas the MCT mice had a more stable enhancement between the pre-chemo and post-chemo time points. This confirms the antiangiogenic effects of 5FU treatment. Comparing amplitude of enhancement revealed a significantly (p<0.05) higher enhancement in the MCT tumors than in the controls. Moreover, the MCT uptake rate was significantly (p<0.001) slower than the controls. dMRI analysis showed the MCT ADC values were significantly larger than the control group at the post-scan time point. Conclusion: dMRI and DCE-MRI can be used as potential biomarkers for assessing the treatment response of MCT. The MRI and pathology observations suggested that in addition to the cytotoxic effect of cell kills, the MCT with a cytotoxic drug, 5FU, induced changes in the tumor vasculature similar to the anti-angiogenic effect.
Datasets for "Contrasting responses of local climate to the perturbation of atmospheric boundary layer winds linked to land–atmosphere interactions"
<p>Datasets for paper "<strong>Contrasting responses of local climate to the perturbation of atmospheric boundary layer winds linked to land–atmosphere interactions"</strong></p>
Data from: Pulmonary nodule detection in patients with a primary malignancy using hybrid PET/MRI: is there value in adding contrast-enhanced MR imaging?
Purpose: To investigate the added value of post-contrast VIBE (volumetric-interpolated breath-hold examination) to PET/MR imaging for pulmonary nodule detection in patients with primary malignancies. Materials and Methods: This retrospective institutional review board–approved study, with waiver of informed consent, included 51 consecutive patients who underwent 18F-fluorodeoxyglucose (FDG) PET/MR followed by PET/CT for cancer staging. In all patients, the thorax was examined with pre-and post-contrast VIBE MR with simultaneous PET acquisition. Two readers blinded to the patients' data independently recorded their level of suspicion for pulmonary nodules based on PET, pre-contrast VIBE, and fused PET/MR images (first session), and reassessed them 4-weeks later after addition of post-contrast VIBE (second session). Jackknife alternative free-response receiver-operating-characteristic (JAFROC) analysis was performed, with PET/CT as the reference standard. Results: A total of 151 pulmonary nodules (44 FDG-avid, 107 non-FDG-avid nodules) were detected on PET/CT, including 62 nodules≥5mm in diameter and 89 nodules<5mm. In the first session, the average nodule detection rate was 53.3% for all nodules, 97.7% for FDG-avid, 35.0% for non-FDG-avid nodules, 87.9% for nodules≥5mm and 29.2% for nodules<5mm. In the second session, the average detection rate was 53.3% for all nodules, 97.7% for FDG-avid, 35.0% for non-FDG-avid nodules, 85.5% for nodules≥5mm and 30.9% for nodules<5mm. The average JAFROC figure-of-merit was 0.837 in the first session and 0.848 in the second session. There were no significant differences in detection performance between sessions (P=0.48). Conclusion: The addition of post-contrast VIBE to hybrid PET/MR imaging provided no additional value in the detection of pulmonary nodules.
Data from: Contrasting evolutionary histories of MHC class I and class II loci in grouse - effects of selection and gene conversion
Genes of the major histocompatibility complex (MHC) encode receptor molecules that are responsible for recognition of intra- and extra-cellular pathogens (class I and class II genes, respectively) in vertebrates. Given the different roles of class I and II MHC genes, one might expect the strength of selection to differ between these two classes. Different selective pressures may also promote different rates of gene conversion at each class. Despite these predictions, surprisingly few studies have looked at differences between class I and II genes in terms of both selection and gene conversion. Here, we investigated the molecular evolution of MHC class I and II genes in five closely related species of prairie grouse (Centrocercus and Tympanuchus) that possess one class I and two class II loci. We found striking differences in the strength of balancing selection acting on MHC class I versus class II genes. More than half of the putative antigen-binding sites (ABS) of class II were under positive or episodic diversifying selection, compared with only 10% at class I. We also found that gene conversion played a stronger role in shaping the evolution of MHC class II than class I. Overall, the combination of strong positive (balancing) selection and frequent gene conversion has maintained higher diversity of MHC class II than class I in prairie grouse. This is one of the first studies clearly demonstrating that macroevolutionary mechanisms can act differently on genes involved in the immune response against intra- and extra-cellular pathogens.
Data from: Contrasting effects of ammonium and nitrate additions on the biomass of soil microbial communities and enzyme activities in subtropical China
The nitrate to ammonium ratios in nitrogen (N) compounds in wet atmospheric deposits have increased over the recent past, which is a cause for some concern as the individual effects of nitrate and ammonium deposition on the biomass of different soil microbial communities and enzyme activities are still poorly defined. We established a field experiment and applied ammonium (NH4Cl) and nitrate (NaNO3) at monthly intervals over a period of 4 years. We collected soil samples from the ammonium and nitrate treatments and control plots in three different seasons, namely spring, summer, and fall, to evaluate the how the biomass of different soil microbial communities and enzyme activities responded to the ammonium (NH4Cl) and nitrate (NaNO3) applications. Our results showed that the total contents of phospholipid fatty acids (PLFAs) decreased by 24 and 11 % in the ammonium and nitrate treatments, respectively. The inhibitory effects of ammonium on Gram-positive bacteria (G+) and bacteria, fungi, actinomycetes, and arbuscular mycorrhizal fungi (AMF) PLFA contents ranged from 14 to 40 % across the three seasons. We also observed that the absolute activities of C, N, and P hydrolyses and oxidases were inhibited by ammonium and nitrate, but that nitrate had stronger inhibitory effects on the activities of acid phosphatase (AP) than ammonium. The activities of N-acquisition specific enzymes (enzyme activities normalized by total PLFA contents) were about 21 and 43 % lower in the ammonium and nitrate treatments than in the control, respectively. However, the activities of P-acquisition specific enzymes were about 19 % higher in the ammonium treatment than in the control. Using redundancy analysis (RDA), we found that the measured C, N, and P hydrolysis and polyphenol oxidase (PPO) activities were positively correlated with the soil pH and ammonium contents, but were negatively correlated with the nitrate contents. The PLFA biomarker contents were positively correlated with soil pH, soil organic carbon (SOC), and total N contents, but were negatively correlated with the ammonium contents. The soil enzyme activities varied seasonally, and were highest in March and lowest in October. In contrast, the contents of the microbial PLFA biomarkers were higher in October than in March and June. Ammonium may inhibit the contents of PLFA biomarkers more strongly than nitrate because of acidification. This study has provided useful information about the effects of ammonium and nitrate on soil microbial communities and enzyme activities.
Data from: Contrasting pattern of natural variation in global Drosophila melanogaster populations
Despite the popularity of Drosophila melanogaster in functional and evolutionary genetics, the global pattern of natural variation has not yet been comprehensively described in this species. For the first time, we report a combined survey using neutral microsatellites and mitochondrial sequence variation jointly. Thirty-five populations originating from five continents were compared. In agreement with previous microsatellite studies, sub-Saharan African populations were the most variable ones. Consistent with previous reports of a single 'out of Africa' habitat expansion, we found that non-African populations contained a subset of the African alleles. The pattern of variation detected for the mitochondrial sequences differed substantially. The most divergent haplotypes were detected in the Mediterranean region while Africa harbored most haplotypes, which were all closely related. In the light of the well-established African origin of D. melanogaster, our results cast severe doubts about the suitability of mtDNA for biogeographic inference in this model organism.
Data from: Continuum of vasodilator stress from rest to contrast medium to adenosine hyperemia for fractional flow reserve assessment
OBJECTIVES: We compared the diagnostic performance with adenosine-derived fractional flow reserve (FFR) #0.8 of contrast-based FFR (cFFR), resting distal pressure (Pd)/aortic pressure (Pa), and the instantaneous wave-free ratio (iFR). BACKGROUND: FFR objectively identifies lesions that benefit from medical therapy versus revascularization. However, FFR requires maximal vasodilation, usually achieved with adenosine. Radiographic contrast injection causes submaximal coronary hyperemia. Therefore, intracoronary contrast could provide an easy and inexpensive tool for predicting FFR. METHODS: We recruited patients undergoing routine FFR assessment and made paired, repeated measurements of all physiology metrics (Pd/Pa, iFR, cFFR, and FFR). Contrast medium and dose were per local practice, as was the dose of intracoronary adenosine. Operators were encouraged to perform both intracoronary and intravenous adenosine assessments and a final drift check to assess wire calibration. A central core lab analyzed blinded pressure tracings in a standardized fashion. RESULTS: A total of 763 subjects were enrolled from 12 international centers. Contrast volume was 8 +- 2 ml per measurement, and 8 different contrast media were used. Repeated measurements of each metric showed a bias <0.005, but a lower SD (less variability) for cFFR than resting indexes. Although Pd/Pa and iFR demonstrated equivalent performance against FFR #0.8 (78.5% vs. 79.9% accuracy, p ¼ 0.78; area under the receiver-operating characteristic curve: 0.875 vs. 0.881, p ¼ 0.35), cFFR improved both metrics (85.8% accuracy and 0.930 area, p < 0.001 for each) with an optimal binary threshold of 0.83. A hybrid decision-making strategy using cFFR required adenosine less often than when based on either Pd/Pa or iFR. CONCLUSIONS: cFFR provides diagnostic performance superior to that of Pd/Pa or iFR for predicting FFR. For clinical scenarios or health care systems in which adenosine is contraindicated or prohibitively expensive, cFFR offers a universal technique to simplify invasive coronary physiological assessments. Yet FFR remains the reference standard for diagnostic certainty as even cFFR reached only ~85% agreement.
Data from: In-vivo imaging of cell migration using contrast enhanced MRI and SVM based post-processing
The migration of cells within a living organism can be observed with magnetic resonance imaging (MRI) in combination with iron oxide nanoparticles as an intracellular contrast agent. This method, however, suffers from low sensitivity and specificty. Here, we developed a quantitative non-invasive in-vivo cell localization method using contrast enhanced multiparametric MRI and support vector machines (SVM) based post-processing. Imaging phantoms consisting of agarose with compartments containing different concentrations of cancer cells labeled with iron oxide nanoparticles were used to train and evaluate the SVM for cell localization. From the magnitude and phase data acquired with a series of -weighted gradient-echo scans at different echo-times, we extracted features that are characteristic for the presence of superparamagnetic nanoparticles, in particular hyper- and hypointensities, relaxation rates, short-range phase perturbations, and perturbation dynamics. High detection quality was achieved by SVM analysis of the multiparametric feature-space. The in-vivo applicability was validated in animal studies. The SVM detected the presence of iron oxide nanoparticles in the imaging phantoms with high specificity and sensitivity with a detection limit of 30 labeled cells per mm3, corresponding to 19 μM of iron oxide. As proof-of-concept, we applied the method to follow the migration of labeled cancer cells injected in rats. The combination of iron oxide labeled cells, multiparametric MRI and a SVM based post processing provides high spatial resolution, specificity, and sensitivity, and is therefore suitable for non-invasive in-vivo cell detection and cell migration studies over prolonged time periods.
Data from: Contrasting effects of specialist and generalist herbivores on resistance evolution in invasive plants
Invasive alien plants are likely to be released from specialist herbivores and at the same time encounter biotic resistance from resident generalist herbivores in their new ranges. The Shifting Defense Hypothesis predicts that this will result in evolution of decreased defense against specialist herbivores and increased defense against generalist herbivores. To test this, we performed a comprehensive meta-analysis of 61 common garden studies that provide data on resistance and/or tolerance for both introduced and native populations of 32 invasive plant species. We demonstrate that introduced populations, relative to native populations, decreased their resistance against specialists, and increased their resistance against generalists. These differences were significant when resistance was measured in terms of damage caused by the herbivore, but not in terms of performance of the herbivore. Furthermore, we found the first evidence that the magnitude of resistance differences between introduced and native populations depended significantly on herbivore origin (i.e. whether the test herbivore was collected from the native or non-native range of the invasive plant). Finally, tolerance to generalists was found to be higher in introduced populations, while neither tolerance to specialists nor that to simulated herbivory differed between introduced and native plant populations. We conclude that enemy release from specialist herbivores and biotic resistance from generalist herbivores have contrasting effects on resistance evolution in invasive plants. Our results thus provide strong support for the Shifting Defense Hypothesis.
Data from: Positive and negative incentive contrasts lead to relative value perception in ants
Humans usually assess things not according to their absolute value, but relative to reference points - a main tenant of Prospect Theory. For example, people rate a new salary relative to previous salaries and salaries of their peers, rather than absolute income. We demonstrate a similar effect in an insect: ants expecting to find low quality food showed higher acceptance of medium quality food than ants expecting medium quality, and vice versa for high expectations. Further experiments demonstrate that these contrast effects arise from cognitive rather than mere sensory or pre-cognitive perceptual causes. Social information gained inside the nest can also serve as a reference point: the quality of food received from other ants affected the perceived value of food found later. Value judgement is a key element in decision making, and thus relative value perception strongly influences which option is chosen and ultimately how all animals make decisions.
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These curated guides explain access requirements, typical timelines, costs, and reuse considerations for widely used research datasets.
Allen Brain Atlas
Allen Brain Atlas is an Allen Institute collection of brain map atlases, datasets, APIs, and analysis tools covering mouse, human, and non-human primate brain resources.
Annotated Behaviour and Observability Dataset (ABODe)
ABODe is a University of Edinburgh DataShare dataset for behavior classification in group-housed mice using home-cage video, identities, bounding boxes, ground-plate positions, and annotator labels.
DANDI Archive for NWB datasets
DANDI is a BRAIN Initiative archive for publishing and sharing neurophysiology data, including electrophysiology, optophysiology, and behavioral data packaged as NWB and related standards.
International Brain Laboratory public data
The International Brain Laboratory public data releases expose standardized mouse decision-making experiments, including Neuropixels recordings, widefield calcium imaging, behavior, and session metadata accessed through the ONE API.
OpenNeuro
OpenNeuro is a free, open platform for sharing neuroimaging datasets, with public search, dataset pages, and download paths for web, S3, DataLad, and the OpenNeuro CLI.