79 research outputs found

    Automatic, fast and robust characterization of noise distributions for diffusion MRI

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    Knowledge of the noise distribution in magnitude diffusion MRI images is the centerpiece to quantify uncertainties arising from the acquisition process. The use of parallel imaging methods, the number of receiver coils and imaging filters applied by the scanner, amongst other factors, dictate the resulting signal distribution. Accurate estimation beyond textbook Rician or noncentral chi distributions often requires information about the acquisition process (e.g. coils sensitivity maps or reconstruction coefficients), which is not usually available. We introduce a new method where a change of variable naturally gives rise to a particular form of the gamma distribution for background signals. The first moments and maximum likelihood estimators of this gamma distribution explicitly depend on the number of coils, making it possible to estimate all unknown parameters using only the magnitude data. A rejection step is used to make the method automatic and robust to artifacts. Experiments on synthetic datasets show that the proposed method can reliably estimate both the degrees of freedom and the standard deviation. The worst case errors range from below 2% (spatially uniform noise) to approximately 10% (spatially variable noise). Repeated acquisitions of in vivo datasets show that the estimated parameters are stable and have lower variances than compared methods.Comment: v2: added publisher DOI statement, fixed text typo in appendix A

    Microbial-based biological treatments improved the nutritional, nutraceutical and functional properties of greenhouse sweet pepper (Capsicum annuum L.)

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    Sweet pepper (Capsicum annum) is an important vegetable with high economic and nutritional value. The present study was conducted to evaluate the effectiveness of biological treatments on the nutritional, nutraceutical and functional status of greenhouse sweet peppers cv. Nirvin. Plants were divided into two categories: Peppers that were biologically treated included five microbial-based fertilizers and insecticide and those that were chemically treated contained a large number of chemical fertilizers and pesticides. The results showed that the total phenolic content, antioxidant activity, and leaf chlorophyll content were significantly higher (1.16, 1.14, and 1.09-fold) in the biologically treated plants compared to those that received the chemical treatment. The concentration of Fe, K, Mg, P, Ca, Cu, Si, and Mn also increased in the fruits of biologically treated sweet pepper plants. Fe, Mg, and P content of the leaves was higher in the chemically treated plants, while, the concentration of Zn and Cu showed the higher values in the leaves of the biologically treated plants. There was no significant difference between biological and chemical treatments in plant height as well as the number of flowers and fruits per plant. In conclusion, biological treatment could significantly improve the nutritional, nutraceutical and functional values of sweet peppers. Considering the risk of environmental pollution, the high cost of chemical fertilizers and pesticides, as well as their adverse impact on human health and the ecosystem, biological treatment can be a suitable alternative for sweet pepper management programs

    Randomized trial of calcipotriol combined with 5-fluorouracil for skin cancer precursor immunotherapy

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    BACKGROUND. Actinic keratosis is a precursor to cutaneous squamous cell carcinoma. Long treatment durations and severe side effects have limited the efficacy of current actinic keratosis treatments. Thymic stromal lymphopoietin (TSLP) is an epithelium-derived cytokine that induces a robust antitumor immunity in barrier-defective skin. Here, we investigated the efficacy of calcipotriol, a topical TSLP inducer, in combination with 5-fluorouracil (5-FU) as an immunotherapy for actinic keratosis. METHODS. The mechanism of calcipotriol action against skin carcinogenesis was examined in genetically engineered mouse models. The efficacy and safety of 0.005% calcipotriol ointment combined with 5% 5-FU cream were compared with Vaseline plus 5-FU for the field treatment of actinic keratosis in a randomized, double-blind clinical trial involving 131 participants. The assigned treatment was self-applied to the entirety of the qualified anatomical sites (face, scalp, and upper extremities) twice daily for 4 consecutive days. The percentage of reduction in the number of actinic keratoses (primary outcome), local skin reactions, and immune activation parameters were assessed. RESULTS. Calcipotriol suppressed skin cancer development in mice in a TSLP-dependent manner. Four-day application of calcipotriol plus 5-FU versus Vaseline plus 5-FU led to an 87.8% versus 26.3% mean reduction in the number of actinic keratoses in participants (P < 0.0001). Importantly, calcipotriol plus 5-FU treatment induced TSLP, HLA class II, and natural killer cell group 2D (NKG2D) ligand expression in the lesional keratinocytes associated with a marked CD4(+) T cell infiltration, which peaked on days 10–11 after treatment, without pain, crusting, or ulceration. CONCLUSION. Our findings demonstrate the synergistic effects of calcipotriol and 5-FU treatment in optimally activating a CD4(+) T cell–mediated immunity against actinic keratoses and, potentially, cancers of the skin and other organs. TRIAL REGISTRATION. ClinicalTrials.gov NCT02019355. FUNDING. Not applicable (investigator-initiated clinical trial)
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