33 research outputs found

    Elastic modulus of multi-walled carbon nanotubes produced by catalytic chemical vapour deposition

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    Carbon nanotubes (CNTs) are ideal structures for use as reinforcement fibres in composite materials, due to their extraordinary mechanical properties, in particular high Young's modulus (E∼1TPa). Usually the high value of E is taken as granted for all types of carbon CNTs. Here we demonstrate that multi-walled carbon nanotubes (MWCNTs) produced by catalytic chemical vapour deposition (CCVD) have low moduli (E<100GPa) independently of their growth conditions. We attribute this to the presence of structural defects. Additional high-temperature annealing failed to improve the mechanical properties. This study urges a better control of the growth process in order to obtain high strength CCVD grown MWCNTs suitable for reinforcement in large-scale industrial application

    Simultaneous resection of colorectal cancer and synchronous liver metastases: what determines the risk of unfavorable outcomes? An international multicenter retrospective cohort study

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    BACKGROUND: The use of a simultaneous resection (SIMR) in patients with synchronous colorectal liver metastases (sCRLM) has increased over the past decades. However, it remains unclear when a SIMR is beneficial and when it should be avoided. The aim of this retrospective cohort study was therefore to compare the outcomes of a SIMR for sCRLM in different settings, and to assess which factors are independently associated with unfavorable outcomes. METHODS: To perform this retrospective cohort study, patients with sCRLM undergoing SIMR (2004-2019) were extracted from an international multicenter database, and their outcomes were compared after stratification according to the type of liver and colorectal resection performed. Factors associated with unfavorable outcomes were identified through multivariable logistic regression. RESULTS: Overall, 766 patients were included, encompassing colorectal resections combined with a major liver resection (n=122), minor liver resection in the anterolateral (n=407), or posterosuperior segments ('Technically major', n=237). Minor and technically major resections, compared to major resections, were more often combined with a rectal resection (29.2 and 36.7 vs. 20.5%, respectively, both P=0.003) and performed fully laparoscopic (22.9 and 23.2 vs. 6.6%, respectively, both P = 0.003). Major and technically major resections, compared to minor resections, were more often associated with intraoperative transfusions (42.9 and 38.8 vs. 20%, respectively, both P = 0.003) and unfavorable incidents (9.6 and 9.8 vs. 3.3%, respectively, both P≤0.063). Major resections were associated, compared to minor and technically major resections, with a higher overall morbidity rate (64.8 vs. 50.4 and 49.4%, respectively, both P≤0.024) and a longer length of stay (12 vs. 10 days, both P≤0.042). American Society of Anesthesiologists grades ≥3 [adjusted odds ratio (aOR): 1.671, P=0.015] and undergoing a major liver resection (aOR: 1.788, P=0.047) were independently associated with an increased risk of severe morbidity, while undergoing a left-sided colectomy was associated with a decreased risk (aOR: 0.574, P=0.013). CONCLUSIONS: SIMR should primarily be reserved for sCRLM patients in whom a minor or technically major liver resection would suffice and those requiring a left-sided colectomy. These findings should be confirmed by randomized studies comparing SIMR with staged resections

    Abstracts of the 33rd International Austrian Winter Symposium : Zell am See, Austria. 24-27 January 2018.

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    Risk Factors of Positive Resection Margin in Laparoscopic and Open Liver Surgery for Colorectal Liver Metastases: A New Perspective in the Perioperative Assessment A European Multicenter Study

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    Objective: To assess the risk factors associated with R1 resection in patients undergoing OLS and LLS for CRLMs. Background: The clinical impact of R1 resection in liver surgery for CRLMs has been continuously appraised, but R1 risk factors have not been clearly defined yet. Methods: A cohort study of patients who underwent OLS and LLS for CRLMs in 9 European high-volume referral centers was performed. A multivariate analysis and the receiver operating characteristic curves were used to investigate the risk factors for R1 resection. A model predicting the likelihood of R1 resection was developed. Results: Overall, 3387 consecutive liver resections for CRLMs were included. OLS was performed in 1792 cases whereas LLS in 1595; the R1 resection rate was 14% and 14.2%, respectively. The risk factors for R1 resection were: The type of resection (nonanatomic and anatomic/nonanatomic), the number of nodules and the size of tumor. In the LLS group only, blood loss was a risk factor, whereas the Pringle maneuver had a protective effect. The predictive size of tumor for R1 resection was >45mm in OLS and >30mm in LLS, > 2 lesions was significative in both groups and blood loss >350 cc in LLS. The model was able to predict R1 resection in OLS (area under curve 0.712; 95% confidence interval 0.665-0.739) and in LLS (area under curve 0.724; 95% confidence interval 0.671-0.745). Conclusions: The study describes the risk factors for R1 resection after liver surgery for CRLMs, which may be used to plan better the perioperative strategies to reduce the incidence of R1 resection during OLS and LLS

    Risk Factors of Positive Resection Margin in Laparoscopic and Open Liver Surgery for Colorectal Liver Metastases: A New Perspective in the Perioperative Assessment A European Multicenter Study

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    Objective: To assess the risk factors associated with R1 resection in patients undergoing OLS and LLS for CRLMs. Background: The clinical impact of R1 resection in liver surgery for CRLMs has been continuously appraised, but R1 risk factors have not been clearly defined yet. Methods: A cohort study of patients who underwent OLS and LLS for CRLMs in 9 European high-volume referral centers was performed. A multivariate analysis and the receiver operating characteristic curves were used to investigate the risk factors for R1 resection. A model predicting the likelihood of R1 resection was developed. Results: Overall, 3387 consecutive liver resections for CRLMs were included. OLS was performed in 1792 cases whereas LLS in 1595; the R1 resection rate was 14% and 14.2%, respectively. The risk factors for R1 resection were: The type of resection (nonanatomic and anatomic/nonanatomic), the number of nodules and the size of tumor. In the LLS group only, blood loss was a risk factor, whereas the Pringle maneuver had a protective effect. The predictive size of tumor for R1 resection was >45mm in OLS and >30mm in LLS, > 2 lesions was significative in both groups and blood loss >350 cc in LLS. The model was able to predict R1 resection in OLS (area under curve 0.712; 95% confidence interval 0.665-0.739) and in LLS (area under curve 0.724; 95% confidence interval 0.671-0.745). Conclusions: The study describes the risk factors for R1 resection after liver surgery for CRLMs, which may be used to plan better the perioperative strategies to reduce the incidence of R1 resection during OLS and LLS

    Composition Effect on the Formation of Oxide Phases by Thermal Decomposition of CuNiM(III) Layered Double Hydroxides with M(III) = Al, Fe

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    : The thermal decomposition processes of coprecipitated Cu-Ni-Al and Cu-Ni-Fe hydroxides and the formation of the mixed oxide phases were followed by thermogravimetry and derivative thermogravimetry analysis (TG - DTG) and in situ X-ray diffraction (XRD) in a temperature range from 25 to 800 °C. The as-prepared samples exhibited layered double hydroxide (LDH) with a rhombohedral structure for the Ni-richer Al- and Fe-bearing LDHs and a monoclinic structure for the CuAl LDH. Direct precipitation of CuO was also observed for the Cu-richest Fe-bearing samples. After the collapse of the LDHs, dehydration, dehydroxylation, and decarbonation occurred with an overlapping of these events to an extent, depending on the structure and composition, being more pronounced for the Fe-bearing rhombohedral LDHs and the monoclinic LDH. The Fe-bearing amorphous phases showed higher reactivity than the Al-bearing ones toward the crystallization of the mixed oxide phases. This reactivity was improved as the amount of embedded divalent cations increased. Moreover, the influence of copper was effective at a lower content than that of nickel
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