910 research outputs found

    Ester-based surfactants: Are they stable enough?

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    Surfactants with an ester bond connecting the polar headgroup and the hydrophobic tail are common. They are easy to synthesize, they can often be made from natural raw materials and their biodegradation profile is generally good, partly due to lipase or esterase catalyzed breakdown of the ester bond in sewage plants. A labile ester bond in the molecule may cause problems, however. Surfactants are often formulated at relatively high pH and it is important that they remain intact for a given period of time. In this article we discuss alkaline hydrolysis of different types of ester-based surfactants—cationic, anionic and nonionic—and also of surfactant mixtures. We show that the ester bond in a surfactant has a different hydrolysis pattern than ester bonds in non-surface active uncharged molecules. Cationic ester-based surfactants are hydrolyzed rapidly while anionic and also nonionic ester-containing surfactants are relatively resistant to hydrolysis

    Production of tumor necrosis factor-α and interleukin-6 in whole blood stimulated by live Gram-negative and Gram-positive bacteria

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    ObjectiveTo investigate the production of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) induced by live Gram-negative and Gram-positive bacteria in whole blood in vitro.MethodsIn all, 49 different isolates were studied. Each of the 49 different isolates was incubated for 4 h with whole blood at a ratio of one monocyte per 1-5 bacteria. Plasma was then separated and frozen, and the concentrations of TNF-α and IL-6 were measured by enzyme immunoassays.ResultsThere was a positive correlation between TNF-α and IL-6 values, r= 0.9. Gram-negative bacteria induced higher levels of both TNF-α and IL-6 than Gram-positive bacteria. Group G streptococci (GGS) induced higher levels of TNF-α than Streptococcus pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis and group A streptococci (GAS). Klebsiella pneumoniae induced higher levels of TNF-α than Haemophilus influenzae, Escherichia coli and Neisseria meningitidis. GGS induced higher levels of IL-6 than Staphylococcus epidermidis, Staphylococcus aureus and GAS. When the relative amounts of cytokine induced by the strains were compared to serum concentrations measured on admission in patients with bacteremia caused by the same bacterial isolates there was no significant correlation.ConclusionSpecies- and strain-related differences in cytokine-inducing properties were found which may have significance in clinical infections

    High resection rates of colorectal liver metastases after standardized follow-up and multimodal management:an outcome study within the COLOFOL trial

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    Background: Outcome after colorectal liver metastases (CRLM) resection has improved over time, despite increased resection rates. Hence, it's crucial to identify all patients possible to treat with curative intent. The objectives of this study were to map recurrence pattern, treatment strategy and survival depending on treatment and follow-up strategy. Methods: In the COLOFOL-trial, patients with radically resected stage II-III colorectal cancer were randomized to high-frequency (6, 12, 18, 24 and 36 months; HF) or low-frequency (12 and 36 months; LF) follow-up. In this study, all CRLM within 5 years were identified and medical files scrutinized. Overall survival (OS) was analysed in uni- and multivariable analyses. Primary endpoint was 5-year OS. Results: Of 2442 patients, 235 (9.6%) developed metachronous CRLM of which 123 (52.3%) underwent treatment with curative intent, resulting in 5-year OS of 58%. Five-year OS for patients with CRLM was 43% after HF versus 24% after LF. The survival benefit was confirmed for HF 8 years from resection of the primary tumour, HR 0.63 (CI 0.46–0.85). Conclusion: A high proportion of metachronous CRLM was possible to treat with curative intent, yielding high survival rates. More intense follow-up after colorectal cancer resection might be of value in high-risk patients

    Prevalence of Epithelial Ovarian Cancer Stem Cells Correlates with Recurrence in Early-Stage Ovarian Cancer

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    Epithelial ovarian cancer stem cells (EOC stem cells) have been associated with recurrence and chemoresistance. CD44 and CK18 are highly expressed in cancer stem cells and function as tools for their identification and characterization. We investigated the association between the number of CD44+ EOC stem cells in ovarian cancer tumors and progression-free survival. EOC stem cells exist as clusters located close to the stroma forming the cancer stem cell “niche”. 17.1% of the samples reveled high number of CD44+ EOC stem cells (>20% positive cells). In addition, the number of CD44+ EOC stem cells was significantly higher in patients with early-stage ovarian cancer (FIGO I/II), and it was associated with shorter progression-free survival (P = 0.026). This study suggests that quantification of the number of EOC stem cells in the tumor can be used as a predictor of disease and could be applied for treatment selection in early-stage ovarian cancer

    Galaxy Zoo: Dust in Spirals

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    We investigate the effect of dust on spiral galaxies by measuring the inclination-dependence of optical colours for 24,276 well-resolved SDSS galaxies visually classified in Galaxy Zoo. We find clear trends of reddening with inclination which imply a total extinction from face-on to edge-on of 0.7, 0.6, 0.5 and 0.4 magnitudes for the ugri passbands. We split the sample into "bulgy" (early-type) and "disky" (late-type) spirals using the SDSS fracdeV (or f_DeV) parameter and show that the average face-on colour of "bulgy" spirals is redder than the average edge-on colour of "disky" spirals. This shows that the observed optical colour of a spiral galaxy is determined almost equally by the spiral type (via the bulge-disk ratio and stellar populations), and reddening due to dust. We find that both luminosity and spiral type affect the total amount of extinction, with "disky" spirals at M_r ~ -21.5 mags having the most reddening. This decrease of reddening for the most luminous spirals has not been observed before and may be related to their lower levels of recent star formation. We compare our results with the latest dust attenuation models of Tuffs et al. We find that the model reproduces the observed trends reasonably well but overpredicts the amount of u-band attenuation in edge-on galaxies. We end by discussing the effects of dust on large galaxy surveys and emphasize that these effects will become important as we push to higher precision measurements of galaxy properties and their clustering.Comment: MNRAS in press. 25 pages, 22 figures (including an abstract comparing GZ classifications with common automated methods for selecting disk/early type galaxies in SDSS data). v2 corrects typos found in proof

    Post-Transplant Outcomes in High-Risk Compared with Non-High-Risk Multiple Myeloma: A CIBMTR Analysis.

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    Conventional cytogenetics and interphase fluorescence in situ hybridization (FISH) identify high-risk multiple myeloma (HRM) populations characterized by poor outcomes. We analyzed these differences among HRM versus non-HRM populations after upfront autologous hematopoietic cell transplantation (autoHCT). Between 2008 and 2012, 715 patients with multiple myeloma identified by FISH and/or cytogenetic data with upfront autoHCT were identified in the Center for International Blood and Marrow Transplant Research database. HRM was defined as del17p, t(4;14), t(14;16), hypodiploidy (-Y) or chromosome 1 p and 1q abnormalities; all others were non-HRM. Among 125 HRM patients (17.5%), induction with bortezomib and immunomodulatory agents (imids) was higher compared with non-HRM (56% versus 43%, P \u3c .001) with similar pretransplant complete response (CR) rates (14% versus 16%, P .1). At day 100 post-transplant, at least a very good partial response was 59% in HRM and 61% in non-HRM (P = .6). More HRM patients received post-transplant therapy with bortezomib and imids (26% versus 12%, P = .004). Three-year post-transplant progression-free (PFS) and overall survival (OS) rates in HRM versus non-HRM were 37% versus 49% (P \u3c .001) and 72% versus 85% (P \u3c .001), respectively. At 3 years, PFS for HRM patients with and without post-transplant therapy was 46% (95% confidence interval [CI], 33 to 59) versus 14% (95% CI, 4 to 29) and in non-HRM patients with and without post-transplant therapy 55% (95% CI, 49 to 62) versus 39% (95% CI, 32 to 47); rates of OS for HRM patients with and without post-transplant therapy were 81% (95% CI, 70 to 90) versus 48% (95% CI, 30 to 65) compared with 88% (95% CI, 84 to 92) and 79% (95% CI, 73 to 85) in non-HRM patients with and without post-transplant therapy, respectively. Among patients receiving post-transplant therapy, there was no difference in OS between HRM and non-HRM (P = .08). In addition to HRM, higher stage, less than a CR pretransplant, lack of post-transplant therapy, and African American race were associated with worse OS. In conclusion, we show HRM patients achieve similar day 100 post-transplant responses compared with non-HRM patients, but these responses are not sustained. Post-transplant therapy appeared to improve the poor outcomes of HRM
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