271 research outputs found

    Development of 17-4PH stainless steel bimodal powder injection molding feedstock with the help of interparticle spacing/lubricating liquid concept

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    Design of a powder injection molding (PIM) feedstock with proper selection of powder with unique particle size, particle shape and solid loading plays a significant role in controlling defects and distortion of PIM products. Using the concept of "interparticle spacing/volume fraction of lubricating liquid" 17-4PH stainless steel feedstocks with various bimodal powder combinations in thermoplastic polymer binder were designed and evaluated using both capillary and torque rheometers. Tendency to powder-binder separation, which is a factor indicating unacceptable distortions of sintered parts, is determined from the density variance during time-dependent viscosity measurement and thresholds in volume fraction of lubricating liquid as well as interparticle spacing parameters. The tailored feedstock with an optimum bimodal powder combination of coarse and fine particles exhibits suitable rheological performance with no evidence of separation and limited sintering distortion. © 2015 Elsevier B.V.Operational Program Research and Development for Innovations - ERDF; National Budget of Czech Republic [CZ.1.05/2.1.00/03.0111

    Xyloccensin L

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    The title compound, C32H40O10, also known as xyloccensin L [systematic name: (1R,4aR,4bS,5aR,6aR,9R,10S,10aS,10bR,2aR,13R)-1-(furan-3-yl)-6a-hy­droxy-10-(2-meth­oxy-2-oxoeth­yl)-9,10a,12a-trimethyl-3-oxododeca­hydro-1H,3H,5aH-6,9-methano­isochromeno[6,5-f]oxireno[g]chromen-13-yl (2E)-2-methyl­but-2-enoate], is a limonoid with a C1—C29 oxygen bridge: this is the first report of the X-ray crystal structure of such a limonoid. Two fused pyran rings and two cyclo­hexane rings adopt boat conformations, while another cyclo­hexane ring and the d-lactone ring are in half-chair conformations. The mol­ecular structure is stabilized by intra­molecular O—H⋯O hydrogen bonding

    Effect of a Soluble Surfactant on a Finite-Sized Bubble Motion in a Blood Vessel

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    We present detailed results for the motion of a finite-sized gas bubble in a blood vessel. The bubble (dispersed phase) size is taken to be such as to nearly occlude the vessel. The bulk medium is treated as a shear thinning Casson fluid and contains a soluble surfactant that adsorbs and desorbs from the interface. Three different vessel sizes, corresponding to a small artery, a large arteriole, and a small arteriole, in normal humans, are considered. The haematocrit (volume fraction of RBCs) has been taken to be 0.45. For arteriolar flow, where relevant, the Fahraeus–Lindqvist effect is taken into account. Bubble motion causes temporal and spatial gradients of shear stress at the cell surface lining the vessel wall as the bubble approaches the cell, moves over it and passes it by. Rapid reversals occur in the sign of the shear stress imparted to the cell surface during this motion. Shear stress gradients together with sign reversals are associated with a recirculation vortex at the rear of the moving bubble. The presence of the surfactant reduces the level of the shear stress gradients imparted to the cell surface as compared to an equivalent surfactant-free system. Our numerical results for bubble shapes and wall shear stresses may help explain phenomena observed in experimental studies related to gas embolism, a significant problem in cardiac surgery and decompression sickness

    Decandrinin, an unprecedented C9C_9-spiro-fused 7,8-seco−ent seco-ent-abietane from the Godavari mangrove Ceriops decandraCeriops\ decandra

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    Decandrinin (1), an unprecedented C9C_9-spiro-fused 7,8-seco−entseco-ent-abietane, was obtained from the bark of an Indian mangrove, Ceriops decandraCeriops\ decandra, collected in the estuary of Godavari, Andhra Pradesh. The constitution and the relative configuration of 1 were determined by HRMS (ESI) and extensive NMR investigations, and the absolute configuration by circular dichroism (CD) and optical-rotatory dispersion (ORD) spectroscopy in combination with quantum-chemical calculations. Decandrinin is the first 7,8-seco−entseco-ent-abietane

    Delta radiomic patterns on serial bi-parametric MRI are associated with pathologic upgrading in prostate cancer patients on active surveillance: preliminary findings

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    ObjectiveThe aim of this study was to quantify radiomic changes in prostate cancer (PCa) progression on serial MRI among patients on active surveillance (AS) and evaluate their association with pathologic progression on biopsy.MethodsThis retrospective study comprised N = 121 biopsy-proven PCa patients on AS at a single institution, of whom N = 50 at baseline conformed to the inclusion criteria. ISUP Gleason Grade Groups (GGG) were obtained from 12-core TRUS-guided systematic biopsies at baseline and follow-up. A biopsy upgrade (AS+) was defined as an increase in GGG (or in number of positive cores) and no upgrade (AS−) was defined when GGG remained the same during a median period of 18 months. Of N = 50 patients at baseline, N = 30 had MRI scans available at follow-up (median interval = 18 months) and were included for delta radiomic analysis. A total of 252 radiomic features were extracted from the PCa region of interest identified by board-certified radiologists on 3T bi-parametric MRI [T2-weighted (T2W) and apparent diffusion coefficient (ADC)]. Delta radiomic features were computed as the difference of radiomic feature between baseline and follow-up scans. The association of AS+ with age, prostate-specific antigen (PSA), Prostate Imaging Reporting and Data System (PIRADS v2.1) score, and tumor size was evaluated at baseline and follow-up. Various prediction models were built using random forest (RF) classifier within a threefold cross-validation framework leveraging baseline radiomics (Cbr), baseline radiomics + baseline clinical (Cbrbcl), delta radiomics (CΔr), delta radiomics + baseline clinical (CΔrbcl), and delta radiomics + delta clinical (CΔrΔcl).ResultsAn AUC of 0.64 ± 0.09 was obtained for Cbr, which increased to 0.70 ± 0.18 with the integration of clinical variables (Cbrbcl). CΔr yielded an AUC of 0.74 ± 0.15. Integrating delta radiomics with baseline clinical variables yielded an AUC of 0.77 ± 0.23. CΔrΔclresulted in the best AUC of 0.84 ± 0.20 (p < 0.05) among all combinations.ConclusionOur preliminary findings suggest that delta radiomics were more strongly associated with upgrade events compared to PIRADS and other clinical variables. Delta radiomics on serial MRI in combination with changes in clinical variables (PSA and tumor volume) between baseline and follow-up showed the strongest association with biopsy upgrade in PCa patients on AS. Further independent multi-site validation of these preliminary findings is warranted

    Endometrial cancer

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    Endometrial cancer is the most common gynecological malignancy in well-developed countries. Biologically and clinicopathologically, endometrial carcinomas are divided into two types: type 1 or estrogen-dependent carcinomas and type 2 or estrogen-independent carcinomas. Type 1 cancers correspond mainly to endometrioid carcinomas and account for approximately 90 % of endometrial cancers, whereas type 2 cancers correspond to the majority of the other histopathological subtypes. The vast majority of endometrial cancers present as abnormal vaginal bleedings in postmenopausal women. Therefore, 75 % of cancers are diagnosed at an early stage, which makes the overall prognosis favorable. The first diagnostic step to evaluate women with an abnormal vaginal bleeding is the measurement of the endometrial thickness with transvaginal ultrasound. If endometrial thickening or heterogeneity is confirmed, a biopsy should be performed to establish a definite histopathological diagnosis. Magnetic resonance imaging is not considered in the International Federation of Gynaecology and Obstetrics staging system. Nonetheless it plays a relevant role in the preoperative staging of endometrial carcinoma, helping to define the best therapeutic management. Moreover, it is important in the diagnosis of treatment complications, in the surveillance of therapy response, and in the assessment of recurrent disease.info:eu-repo/semantics/publishedVersio
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