685 research outputs found

    Observations on the desiccation and cracking of clay layers

    Get PDF
    Waterways and lakes in low-lying delta areas require regular dredging for maintenance. Often these sediments are placed on land, where they are allowed to ripen through a combination of drainage, consolidation and evaporation. When cracks develop during desiccation, the physical response of the soil is affected by changes in the overall strength, stiffness and permeability of the material. To better identify how cracks form and propagate, a series of tests was carried out in a controlled laboratory environment on samples of drying clay slurries under different initial and boundary conditions. The outcomes of this study indicate that the results from laboratory small scale models must be carefully analyzed, as they depend on the area and the thickness of the sample. However, common features from the different tests can be identified, which are mostly related to the intrinsic behavior of the material. For instance, the water content at which cracks initiate depends mostly on the drying rate and not only on the initial water content. Typically for the clayey soil investigated, the cracking water content is well above the shrinkage limit and in some instances even above the liquid limit. Cracks can form anywhere a defect is encountered, but it was observed that they propagate in horizontal directions below the soil surface. On the soil surface they tend to intersect with each other perpendicularly, suggesting that they are dominated by a tensile stress regime. Shear stresses also influence the response, but mainly near the boundaries of the samples, due to the interface friction

    Prevalence of BRCA1 in a hospital-based population of Dutch breast cancer patients

    Get PDF
    The prevalence of disease-related BRCA1 mutations was investigated in 642 Dutch breast cancer patients not selected for family history or age at diagnosis. They were tested for germline mutations in the BRCA1 gene using an assay which detects small deletions and insertions (DSDI), as well as the two major genomic founder deletions present in the Dutch population. Data on family history and bilateral breast cancer were obtained retrospectively. Ten protein truncating mutations were detected and one in-frame deletion with an unknown relation to disease risk. Four patients carried the Dutch founder deletion of exon 22. Based on these results the estimated prevalence of breast cancer in the general population in the Netherlands attributable to BRCA1 mutations is 2.1%. Under 40 years-of-age and under 50 years-of-age this prevalence is 9.5% and 6.4%, respectively. All mutation carriers were under 50 years-of-age at diagnosis of the first breast cancer, and five did not have any relative with breast cancer. The proportions of bilateral breast cancer in the mutation carriers and non-carriers did not differ from each other. These data indicate that in the general Dutch breast cancer population the great majority of BRCA1 mutations will be found in women diagnosed under 50 years-of-age. Ā© 2000 Cancer Research Campaig

    Antibodies against p53 are associated with poor prognosis of colorectal cancer.

    Get PDF
    Mutation of the p53 gene is a common event in colorectal cancer. This alteration can result in cellular accumulation of p53 and may also induce p53 antibodies. Accumulation of p53 in tumour cells has been associated with poor prognosis of colorectal cancer. We tested preoperative sera from 255 patients with colorectal cancer by enzyme-linked immunosorbent assay (ELISA). A total of 70.2% had reactivity that was higher than the 'low' control serum. Employing a cut-off level of 10% of the 'high' control sample, 25.5% of the patients were positive for p53 antibodies. The presence of p53 antibodies correlated with the following prognostic factors: histological differentiation grade, shape of the tumour, and tumour invasion into blood vessels. Patients with p53 antibodies were shown to have decreased survival and decreased disease-free survival. Specifically for patients with cancer stage A and B1 the presence of p53 antibodies selected a subgroup with poor prognosis

    A 10-year evaluation of short-term outcomes after synchronous colorectal cancer surgery: a Dutch population-based study

    Get PDF
    Background Synchronous colorectal cancer (CRC) has been associated with higher postoperative morbidity and mortality rates compared to solitary CRC. The influence of improved CRC care and introduction of screening on these outcomes remains unknown. This study aimed to evaluate time trends in incidence, population characteristics, and short-term outcomes of synchronous CRC patients at the population level over a 10-year time period. Methods Data of all patients that underwent resection for primary CRC were extracted from the Dutch ColoRectal Audit (2010-2019). Analyses were stratified for solitary and synchronous colon and rectal cancer. Multilevel logistic regression analyses were used to determine factors associated with pathological and surgical outcomes. Results Among 100,474 patients, 3.1% underwent surgery for synchronous CRC. A screening-related decrease for surgically treated left-sided solitary and synchronous colon cancer and a temporary increase for exclusively right-sided colon cancer were observed. Synchronous CRC patients had higher rates of complicated postoperative course, failure to rescue, and mortality. Bilateral synchronous colon cancer was more often treated with subtotal colectomy (25.4%) and demonstrated higher rates of surgical complications, reinterventions, prolonged hospital stay, and mortality than other synchronous tumor locations. Discussion National bowel screening resulted in contradictory effects on surgical resections for synchronous CRCs depending on sidedness. Bilateral synchronous colon cancer required more often extended resection resulting in significantly worse outcomes than other synchronous tumor locations. Identification of low volume, high complex CRC subpopulations is relevant for individualized care and has implications for case-mix correction and benchmarking in clinical auditing.Surgical oncolog

    Adaptation of Arabidopsis to nitrogen limitation involves induction of anthocyanin synthesis which is controlled by the NLA gene

    Get PDF
    Plants can survive a limiting nitrogen (N) supply by developing a set of N limitation adaptive responses. However, the Arabidopsis nla (nitrogen limitation adaptation) mutant fails to produce such responses, and cannot adapt to N limitation. In this study, the nla mutant was utilized to understand further the effect of NLA on Arabidopsis adaptation to N limitation. Grown with limiting N, the nla mutant could not accumulate anthocyanins and instead produced an N limitation-induced early senescence phenotype. In contrast, when supplied with limiting N and limiting phosphorus (Pi), the nla mutants accumulated abundant anthocyanins and did not show the N limitation-induced early senescence phenotype. These results support the hypothesis that Arabidopsis has a specific pathway to control N limitation-induced anthocyanin synthesis, and the nla mutation disrupts this pathway. However, the nla mutation does not affect the Pi limitation-induced anthocyanin synthesis pathway. Therefore, Pi limitation induced the nla mutant to accumulate anthocyanins under N limitation and allowed this mutant to adapt to N limitation. Under N limitation, the nla mutant had a significantly down-regulated expression of many genes functioning in anthocyanin synthesis, and an enhanced expression of genes involved in lignin production. Correspondingly, the nla mutant grown with limiting N showed a significantly lower production of anthocyanins (particularly cyanidins) and an increase in lignin contents compared with wild-type plants. These data suggest that NLA controls Arabidopsis adaptability to N limitation by channelling the phenylpropanoid metabolic flux to the induced anthocyanin synthesis, which is important for Arabidopsis to adapt to N limitation

    Textbook outcome after rectal cancer surgery as a composite measure for quality of care: A population-based study

    Get PDF
    ABSTRACTBackground: Textbook outcome is a composite measure of combined outcome indicators, which has been suggested to be of additional value over single outcome parameters in clinical auditing of surgical treatment. This study aimed to assess textbook outcome after rectal cancer surgery as short-term marker for quality of care.Methods: Patients who underwent elective rectal cancer surgery between 2012 and 2019 and registered in the Dutch ColoRectal Audit were included when the following criteria were met: 30-day and primary hospital admission survival, no reintervention, tumor-free margins, no postoperative complications, a hospital stay of less than 14 days and no readmission. Hospital variation was evaluated in case-mix corrected funnel-plots. A multilevel logistic regression analysis was performed to identify associated factors with textbook outcome.Results: The study population consisted of 20,521 patients who underwent primary rectal cancer surgery, of whom 56.3% achieved textbook outcome. Postoperative complications were the main contributor to not achieving textbook outcome. Case-mix corrected funnel plots demonstrated that underperforming hospitals in 2012-2015 were no underperformers in 2016-2019 anymore. Female sex, laparoscopic surgery, and rectal resection without defunctioning stoma creation were positively associated with textbook outcome.Conclusion: Textbook outcome after rectal cancer resection is mainly driven by postoperative complications. Although textbook outcome showed some discriminating value for identifying underperforming hospitals, it does not fit the plan-do-check-act cycle of clinical auditing. In our opinion, textbook outcome has little added value to the current outcome indicators for rectal cancer surgery.KEYWORDS: Rectal cancer - Surgery - Textbook outcome - Clinical auditing - Hospital variation - Outcome indicatorSurgical oncolog
    • ā€¦
    corecore