CFD modelling of powder flow in a continuous horizontal mixer

This work presents a continuum model for simulating the flow of powders inside continuous horizontal mixers. The challenge is to adopt a reliable rheological model that allows simulating granular flows accurately. We selected the μ(I)-rheology model. First, we considered a set of granular collapse experiments, showing that the model can successfully reproduce these flows, and also using the experimental results to evaluate the material properties of the powders. Then, we investigated the complex powder flow in continuous horizontal mixers. Here computational cost is a challenge. We showed that the sliding mesh technique is accurate but expensive owing to the rotation of the boundaries, making this method impractical for industrial applications. Therefore, we also employed the multiple reference frame technique, showing that its results are accurate at far lower computational cost. The results section ends with a sensitivity analysis of the mixer solid mass loading to the powder material properties

Synthetic Lethality of Chk1 Inhibition Combined with p53 and/or p21 Loss During a DNA Damage Response in Normal and Tumor Cells

Cell cycle checkpoints ensure genome integrity and are frequently compromised in human cancers. A therapeutic strategy being explored takes advantage of checkpoint defects in p53-deficient tumors in order to sensitize them to DNA-damaging agents by eliminating Chk1-mediated checkpoint responses. Using mouse models, we demonstrated that p21 is a key determinant of how cells respond to the combination of DNA damage and Chk1 inhibition (combination therapy) in normal cells as well as in tumors. Loss of p21 sensitized normal cells to the combination therapy much more than did p53 loss and the enhanced lethality was partially blocked by CDK inhibition. In addition, basal pools of p21 (p53 independent) provided p53 null cells with protection from the combination therapy. Our results uncover a novel p53-independent function for p21 in protecting cells from the lethal effects of DNA damage followed by Chk1 inhibition. As p21 levels are low in a significant fraction of colorectal tumors, they are predicted to be particularly sensitive to the combination therapy. Results reported in this study support this prediction

Widening participation in higher education: student quantitative skills and independent learning as impediments to progression

The UK government's widening participation strategy, and the concomitant development of a mass higher education system, has imposed a variety of pressures on higher education institutions. Not least of these is the changing nature of the student population, and the assumptions that can be made about its skills and knowledge base. It should not be surprising that this rapid expansion of the higher education system has resulted in declining student progression and retention rates. This paper takes a case study approach and attempts to identify the range of factors that might explain the variability of student performance on a first year undergraduate introductory statistics module. The paper concludes that there are no simple predictors of success or failure. However, there is evidence to suggest that any innovations in delivery need to take account of individual student development and that the presumption that students can rapidly become independent learners upon initial entry to higher education is an unrealistic one

Effects of work-related factors on the breastfeeding behavior of working mothers in a Taiwanese semiconductor manufacturer: a cross-sectional survey

BACKGROUND: In recent years, the creation of supportive environments for encouraging mothers to breastfeed their children has emerged as a key health issue for women and children. The provision of lactation rooms and breast pumping breaks have helped mothers to continue breastfeeding after returning to work, but their effectiveness is uncertain. The aim of this study was to assess the effects of worksite breastfeeding-friendly policies and work-related factors on the behaviour of working mothers. METHODS: This study was conducted at a large Taiwanese semiconductor manufacturer in August-September 2003. Questionnaires were used to collect data on female employees' breastfeeding behaviour, child rearing and work status when raising their most recently born child. A total of 998 valid questionnaires were collected, giving a response rate of 75.3%. RESULTS: The results showed that 66.9% of survey respondents breastfed initially during their maternity leave, which averaged 56 days. Despite the provision of lactation rooms and breast pumping breaks, only 10.6% mothers continued to breastfeed after returning to work, primarily office workers and those who were aware of their company's breastfeeding-friendly policies. CONCLUSION: In conclusion, breastfeeding-friendly policies can significantly affect breastfeeding behaviour. However, an unfavourable working environment, especially for fab workers, can make it difficult to implement breastfeeding measures. With health professionals emphasizing that the importance of breastfeeding for infant health, and as only females can perform lactation, it is vital that women's work "productive role" and family "reproductive role" be respected and accommodated by society

Role of nickel in high rate methanol degradation in anaerobic granular sludge bioreactors

The effect of nickel deprivation from the influent of a mesophilic (30°C) methanol fed upflow anaerobic sludge bed (UASB) reactor was investigated by coupling the reactor performance to the evolution of the Methanosarcina population of the bioreactor sludge. The reactor was operated at pH 7.0 and an organic loading rate (OLR) of 5–15 g COD l−1 day−1 for 191 days. A clear limitation of the specific methanogenic activity (SMA) on methanol due to the absence of nickel was observed after 129 days of bioreactor operation: the SMA of the sludge in medium with the complete trace metal solution except nickel amounted to 1.164 (±0.167) g CH4-COD g VSS−1 day−1 compared to 2.027 (±0.111) g CH4-COD g VSS−1 day−1 in a medium with the complete (including nickel) trace metal solution. The methanol removal efficiency during these 129 days was 99%, no volatile fatty acid (VFA) accumulation was observed and the size of the Methanosarcina population increased compared to the seed sludge. Continuation of the UASB reactor operation with the nickel limited sludge lead to incomplete methanol removal, and thus methanol accumulation in the reactor effluent from day 142 onwards. This methanol accumulation subsequently induced an increase of the acetogenic activity in the UASB reactor on day 160. On day 165, 77% of the methanol fed to the system was converted to acetate and the Methanosarcina population size had substantially decreased. Inclusion of 0.5 μM Ni (dosed as NiCl2) to the influent from day 165 onwards lead to the recovery of the methanol removal efficiency to 99% without VFA accumulation within 2 days of bioreactor operation

Author Correction to: The VAR2CSA malaria protein efficiently retrieves circulating tumor cells in an EpCAM-independent manner (Nature Communications, (2018), 9, 1, (3279), 10.1038/s41467-018-05793-2)

This Article contained an error in the consent of some of the patients used in Figure 4. Following an institute-led investigation within BARTS Cancer Institute post-publication, no documentation of informed consent from the nine lung cancer patients whose blood samples were used in this research project could be recovered and therefore, this data have been removed from the published article.The patients and their families were informed of the original error and apologies were made.The following changes have been made to the paper to remove all mention of the lung cancer samples and the data associated with them.In the abstract, the sentence ‘We show that rVAR2 efficiently captures CTCs from hepatic, lung, pancreatic, and prostate carcinomapatients with minimal contamination of peripheral blood mononuclear cells.’ has been changed to read ‘We show that rVAR2 efficiently captures CTCs from hepatic, pancreatic, and prostate carcinoma patients with minimal contamination of peripheral blood mononuclear cells

Proof-carrying plans

It is becoming increasingly important to verify safety and security of AI applications. While declarative languages (of the kind found in automated planners and model checkers) are traditionally used for verifying AI systems, a big challenge is to design methods that generate verified executable programs. A good example of such a “verification to implementation” cycle is given by automated planning languages like PDDL, where plans are found via a model search in a declarative language, but then interpreted or compiled into executable code in an imperative language. In this paper, we show that this method can itself be verified. We present a formal framework and a prototype Agda implementation that represent PDDL plans as executable functions that inhabit types that are given by formulae describing planning problems. By exploiting the well-known Curry-Howard correspondence, type-checking then automatically ensures that the generated program corresponds precisely to the specification of the planning problem.Postprin

Identification of gene polymorphisms of human DNA topoisomerase I in the National Cancer Institute panel of human tumour cell lines

Topoisomerase 1 (Top1), a nuclear enzyme involved in DNA relaxation, is the target of several anticancer drugs. TOP1 mutations occur in camptothecin-resistant tumour cell lines. We explored, in the NCI panel of 60 human tumour cell lines, whether polymorphic variations in the TOP1 gene could explain differences in drug sensitivity. The 21 exons of the gene were fully studied as well as five intronic domains that had previously been shown to harbour single nucleotide polymorphisms (SNPs) or mutations. PCR products covering the whole exonic sequences or the relevant intronic domains were subjected to denaturing high-performance liquid chromatography. Nucleotide variations were then determined by sequencing. Discrimination between intronic common and variant homozygous samples was performed using a restriction fragment length polymorphism technique. Only one exonic mutation was detected, at the heterozygous state; it occurs in exon 19 of a colon cancer cell line (HCT-15) and consists of a G>A transition at position 75, resulting in a Met675Ile change. The intronic sequences studied harboured the SNPs expected with allelic frequencies between 20 and 40%. Three major haplotypes, generating 92% of the 10 genotypes encountered, were defined as containing none of the intronic SNPs, or three of them, or all of them. No significant relationship was evidenced between Top1 expression and the TOP1 polymorphisms studied. However, when comparing the cytotoxicity of 138 drugs as a function of the genotypes, several drug groups, namely Top1 inhibitors, antifolates and taxanes, had significantly different IC50s as a function of the distribution of the intronic SNPs of the TOP1 gene