178 research outputs found

    Aerobic Oxidation of Cyclohexane Catalyzed by Flame-Made Nano-Structured Co/SiO2 Materials

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    The aerobic oxidation of cyclohexane was studied at 130°C in the presence of a Co/SiO2 catalyst, synthesized by flame-spray pyrolysis. Characterization of the material indicates that at low Co-loadings, CoII is predominantly present as tetrahedral species, whereas at higher loadings also small amounts of octahedral species can be found at the surface of the agglomerated nano-particles. Catalytic experiments demonstrate high activity, causing a complete in situ deperoxidation of the intermediate cyclohexylhydroperoxide. Hot-separation and catalyst-recycle tests corroborate the heterogeneous nature of the catalys

    Value of T2 Mapping MRI for Prostate Cancer Detection and Classification.

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    Currently, multi-parametric prostate MRI (mpMRI) consists of a qualitative T <sub>2</sub> , diffusion weighted, and dynamic contrast enhanced imaging. Quantification of T <sub>2</sub> imaging might further standardize PCa detection and support artificial intelligence solutions. To evaluate the value of T <sub>2</sub> mapping to detect prostate cancer (PCa) and to differentiate PCa aggressiveness. Retrospective single center cohort study. Forty-four consecutive patients (mean age 67 years; median PSA 7.9 ng/mL) with mpMRI and verified PCa by subsequent targeted plus systematic MR/ultrasound (US)-fusion biopsy from February 2019 to December 2019. Standardized mpMRI at 3 T with an additionally acquired T <sub>2</sub> mapping sequence. Primary endpoint was the analysis of quantitative T <sub>2</sub> values and contrast differences/ratios (CD/CR) between PCa and benign tissue. Secondary objectives were the correlation between T <sub>2</sub> values, ISUP grade, apparent diffusion coefficient (ADC) value, and PI-RADS, and the evaluation of thresholds for differentiating PCa and clinically significant PCa (csPCa). Mann-Whitney test, Spearman's rank (r <sub>s</sub> ) correlation, receiver operating curves, Youden's index (J), and AUC were performed. Statistical significance was defined as P < 0.05. Median quantitative T <sub>2</sub> values were significantly lower for PCa in PZ (85 msec) and PCa in TZ (75 msec) compared to benign PZ (141 msec) or TZ (97 msec) (P < 0.001). CD/CR between PCa and benign PZ (51.2/1.77), respectively TZ (19.8/1.29), differed significantly (P < 0.001). The best T <sub>2</sub> -mapping threshold for PCa/csPCa detection was for TZ 81/86 msec (J = 0.929/1.0), and for PZ 110 msec (J = 0.834/0.905). Quantitative T <sub>2</sub> values of PCa did not correlate significantly with the ISUP grade (r <sub>s</sub> = 0.186; P = 0.226), ADC value (r <sub>s</sub> = 0.138; P = 0.372), or PI-RADS (r <sub>s</sub> = 0.132; P = 0.392). Quantitative T <sub>2</sub> values could differentiate PCa in TZ and PZ and might support standardization of mpMRI of the prostate. Different thresholds seem to apply for PZ and TZ lesions. However, in the present study quantitative T <sub>2</sub> values were not able to indicate PCa aggressiveness. 2 TECHNICAL EFFICACY: Stage 2

    The Emp24 Complex Recruits a Specific Cargo Molecule into Endoplasmic Reticulum–Derived Vesicles

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    Members of the yeast p24 family, including Emp24p and Erv25p, form a heteromeric complex required for the efficient transport of selected proteins from the endoplasmic reticulum (ER) to the Golgi apparatus. The specific functions and sites of action of this complex are unknown. We show that Emp24p is directly required for efficient packaging of a lumenal cargo protein, Gas1p, into ER-derived vesicles. Emp24p and Erv25p can be directly cross-linked to Gas1p in ER-derived vesicles. Gap1p, which was not affected by emp24 mutation, was not cross-linked. These results suggest that the Emp24 complex acts as a cargo receptor in vesicle biogenesis from the ER

    Arterial input function for quantitative dynamic contrast-enhanced MRI to diagnose prostate cancer

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    PURPOSEThis study aims to analyze the ability of quantitative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to distinguish between prostate cancer (PCa) and benign lesions in transition zone (TZ) and peripheral zone (PZ) using different methods for arterial input function (AIF) determination. Study endpoints are identification of a standard AIF method and optimal quantitative perfusion parameters for PCa detection.METHODSDCE image data of 50 consecutive patients with PCa who underwent multiparametric MRI were analyzed retrospectively with three different methods of AIF acquisition. First, a region of interest was manually defined in an artery (AIFm); second, an automated algorithm was used (AIFa); and third, a population-based AIF (AIFp) was applied. Values of quantitative parameters after Tofts (Ktrans, ve, and kep) in PCa, PZ, and TZ in the three different AIFs were analyzed.RESULTSKtrans and kep were significantly higher in PCa than in benign tissue independent from the AIF method. Whereas in PZ, Ktrans and kep could differentiate PCa (P < .001), in TZ only kep using AIFpdemonstrated a significant difference (P = .039). The correlations of the perfusion parameters that resulted from AIFm and AIFa were higher than those that resulted from AIFp, and the absolute values of Ktrans, kep, and ve were significantly lower when using AIFp. The values of quantitative perfusion parameters for PCa were similar regardless of whether PCa was located in PZ or TZ.CONCLUSIONKtrans and kep were able to differentiate PCa from benign PZ independent of the AIF method. AIFaseems to be the most feasible method of AIF determination in clinical routine. For TZ, none of the quantitative perfusion parameters provided satisfying results

    Equivocal pi-rads three lesions on prostate magnetic resonance imaging: Risk stratification strategies to avoid mri-targeted biopsies

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    We aimed to investigate the relation between largest lesion diameter, prostate-specific antigen density (PSA-D), age, and the detection of clinically significant prostate cancer (csPCa) using first-time targeted biopsy (TBx) in men with Prostate Imaging—Reporting and Data System (PI-RADS) 3 index lesions. A total of 292 men (2013–2019) from two referral centers were included. A multivariable logistic regression analysis was performed. The discrimination and clinical utility of the built model was assessed by the area under the receiver operation curve (AUC) and decision curve analysis, respectively. A higher PSA-D and higher age were significantly related to a higher risk of detecting csPCa, while the largest index lesion diameter was not. The discrimination of the model was 0.80 (95% CI 0.73–0.87). When compared to a biopsy-all strategy, decision curve analysis showed a higher net benefit at threshold probabilities of ≄2%. Accepting a missing ≀5% of csPCa diagnoses, a risk-based approach would result in 34% of TBx sessions and 23% of low-risk PCa diagnoses being avoided. In men with PI-RADS 3 index lesions scheduled for first-time TBx, the balance between the number of TBx sessions, the detection of low-risk PCa, and the detection of csPCa does not warrant a biopsy-all strategy. To minimize the risk of missing the diagnosis of csPCa but acknowledging the need of avoiding unnecessary TBx sessions and overdiagnosis, a risk-based approach is advisable

    Unconventional secretion of Acb1 is mediated by autophagosomes

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    Evidence is presented for an unconventional protein secretion pathway that is conserved from yeast to Dictyostelium discoideum in which Acb1 may be sequestered into autophagosomal vesicles, which then fuse (either directly or indirectly) with the plasma membrane (see also the companion paper from Manjithaya et al. in this issue)

    Transport of Axl2p Depends on Erv14p, an ER–Vesicle Protein Related to the Drosophila cornichon Gene Product

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    COPII-coated ER-derived transport vesicles from Saccharomyces cerevisiae contain a distinct set of membrane-bound polypeptides. One of these polypeptides, termed Erv14p (ER–vesicle protein of 14 kD), corresponds to an open reading frame on yeast chromosome VII that is predicted to encode an integral membrane protein and shares sequence identity with the Drosophila cornichon gene product. Experiments with an epitope-tagged version of Erv14p indicate that this protein localizes to the ER and is selectively packaged into COPII-coated vesicles. Haploid cells that lack Erv14p are viable but display a modest defect in bud site selection because a transmembrane secretory protein, Axl2p, is not efficiently delivered to the cell surface. Axl2p is required for selection of axial growth sites and normally localizes to nascent bud tips or the mother bud neck. In erv14Δ strains, Axl2p accumulates in the ER while other secretory proteins are transported at wild-type rates. We propose that Erv14p is required for the export of specific secretory cargo from the ER. The polarity defect of erv14Δ yeast cells is reminiscent of cornichon mutants, in which egg chambers fail to establish proper asymmetry during early stages of oogenesis. These results suggest an unforeseen conservation in mechanisms producing cell polarity shared between yeast and Drosophila
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