Aggregate effect on the concrete cone capacity of an undercut anchor under quasi-static tensile load

In the last decades, fastening systems have become an essential part of the construction industry. Post-installed mechanical anchors are frequently used in concrete members to connect them with other load bearing structural members, or to attach appliances. Their performance is limited by the concrete related failure modes which are highly influenced by the concrete mix design. This paper aims at investigating the effect that different aggregates used in the concrete mix have on the capacity of an undercut anchor under tensile quasi-static loading. Three concrete batches were cast utilising three different aggregate types. For two concrete ages (28 and 70 days), anchor tensile capacity and concrete properties were obtained. Concrete compressive strength, fracture energy and elastic modulus are used to normalize and compare the undercut anchor concrete tensile capacity employing some of the most widely used prediction models. For a more insightful comparison, a statistical method that yields also scatter information is introduced. Finally, the height and shape of the concrete cones are compared by highly precise and objective photogrammetric means

Multiple Signalling Pathways Establish Cell Fate and Cell Number in Drosophila Malpighian Tubules

AbstractA unique cell, the tip mother cell, arises in the primordium of each Drosophila Malpighian tubule by lateral inhibition within a cluster of achaete-expressing cells. This cell maintains achaete expression and divides to produce daughters of equivalent potential, of which only one, the tip cell, adopts the primary fate and continues to express achaete, while in the other, the sibling cell, achaete expression is lost (M. Hoch et al., 1994, Development 120, 3439–3450). In this paper we chart the mechanisms by which achaete expression is differentially maintained in the tip cell lineage to stabilise cell fate. First, wingless is required to maintain the expression of achaete in the tubule primordium so that wingless mutants lack tip cells. Conversely, increasing wingless expression results in the persistence of achaete expression in the cell cluster. Second, Notch signalling is restricted by the asymmetric segregation of Numb, as the tip mother cell divides, so that achaete expression is maintained only in the tip cell. In embryos mutant for Notch tip cells segregate at the expense of sibling cells, whereas in numb neither daughter cell adopts the tip cell fate resulting in tubules with two sibling cells. Conversely, when numb is overexpressed two tip cells segregate and tubules have no sibling cells. Analysis of cell proliferation in the developing tubules of embryos lacking Wingless after the critical period for tip cell allocation reveals an additional requirement for wingless for the promotion of cell division. In contrast, alteration in the expression of numb has no effect on the final tubule cell number

Predictors of breastfeeding initiation in Hong Kong and Mainland China born mothers

© 2015 Lok et al.Background: In recent years there has been a steady influx of immigrants into Hong Kong from Mainland China, where breastfeeding patterns differ. Studies in other regions have found substantial differences in breastfeeding rates between native-born and immigrant mothers. The purpose of this study was to examine factors associated with breastfeeding initiation in Hong Kong born and Mainland China born mothers living in Hong Kong. Methods: We used a multi-center cross-sectional study design and recruited 2761 new mothers from the postnatal wards of all eight public hospitals in Hong Kong that offer obstetric services. We assessed breastfeeding status as well as various socio-demographic, maternal and birth characteristics. Chi-square tests and multivariable logistic regression were used to identify the predictors of breastfeeding initiation in Hong Kong born and Mainland China born participants. Results: 80.3% of Hong Kong and 81.1% of Mainland Chinese born women initiated breastfeeding. In the fully adjusted models, multiparity (Odds Ratio [OR] 0.53, 95% CI 0.43-0.66) and maternal smoking (OR 0.29, 95% CI 0.18-0.45) were strongly associated with failure to initiate breastfeeding in both Hong Kong and Mainland China born participants. In Hong Kong born mothers, participants with lower maternal education and those who had a cesarean section were significantly less likely to breastfeed. For Mainland China born mothers, paternal smoking (OR 0.70, 95% CI 0.49-0.99) and having a pregnancy-related health problem (OR 0.60, 95% CI 0.38-0.94) were both additional risk factors for not breastfeeding. Conclusion: This study has identified predictors of breastfeeding initiation in Hong Kong and Mainland China born mothers. Given the current high breastfeeding initiation rates among both groups, antenatal breastfeeding education and promotion programmes need to specifically intervene with sub-groups of pregnant women at risk for not breastfeeding so that their efforts are more strategic and cost-effective.published_or_final_versio

Comprehensive data collection for the development of anchorage lifetime prediction models

Nowadays, fastening systems represent a very important part of the construction industry due to their versatility and use in reconstruction. Therefore, it is essential to study and understand phenomena and effects influencing the lifetime of a fastening system. However, the mechanisms are complex and not yet fully understood. As a result, numerical models, which are reliable and are able to capture all involved effects, are needed. The basis of these models is a wide range of high quality data, for model development, calibration, and validation purposes. Within the 7‐year Christian Doppler Laboratory (CDL) of Life Cycle Robustness, an extensive concrete data base, consisting of short‐term mechanical properties of concrete, time‐dependent measurements as well as tests on full fastening systems, was generated. The material tests reach from compression, indirect tensile, and fracture tests to long‐term creep and shrinkage tests. Shear and pull‐out tests were carried out on bonded and mechanical anchors. In order to characterize the long‐term performance, sustained load and time to failure tests were conducted at a system level. In total, 12 concrete mixes were tested. This contribution will give an overview of the performed tests and will highlight the importance of sound experimental data

Macrophage VLDL Receptor Promotes PAFAH Secretion in Mother’s Milk and Suppresses Systemic Inflammation in Nursing Neonates

Mother’s milk is widely accepted as nutritious and protective to the newborn mammals by providing not only macronutrients but also immune-defensive factors. However, the mechanisms accounting for these benefits are not fully understood. Here we show that maternal very-low-density-lipoprotein receptor (VLDLR) deletion in mice causes the production of defective milk containing diminished level of platelet-activating factor acetylhydrolase (PAFAH). As a consequence, the nursing neonates suffer from alopecia, anemia and growth retardation owing to elevated levels of pro-inflammatory platelet-activating factors (PAFs). VLDLR deletion significantly impairs the expression of phospholipase A2 group 7 (Pla2g7) in macrophages, which decreases PAFAH secretion. Exogenous oral supplementation of neonates with PAFAH effectively rescues the toxicity. These findings not only reveal a novel role of VLDLR in suppressing inflammation by maintaining macrophage PAFAH secretion, but also identify the maternal VLDLR as a key genetic program that ensures milk quality and protects the newborns.Chemistry and Chemical Biolog

Lower hybrid current drive and ion cyclotron range of frequencies heating experiments in H-mode plasmas in experimental advanced superconducting Tokomak

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LHCD and ICRF heating experiments in H-mode plasmas on EAST

An ICRF system with power up to 6.0 MW and a LHCD system up to 4MW have been applied for heating and current drive experiments on EAST. Intensive lithium wall coating was intensively used to reduce particle recycling and Hydrogen concentration in Deuterium plasma, which is needed for effective ICRF and LHCD power absorption in high density plasmas. Significant progress has been made with ICRF heating and LHW current drive for realizing the H-mode plasma operation in EAST. In 2010, H-mode was generated and sustained by LHCD alone, where lithium coating and gas puffing launcher mouth were applied to improve the LHCD power coupling and penetration into the core plasmas at high density of H-modes. During the last two experimental campaigns, ICRF Heating experiments were carried out at the fixed frequency of 27MHz, achieving effective ions and electrons heating with the H Minority Heating (H-MH) mode, where electrons are predominantly heated by collisions with high energy minority ions. The H-MH mode gave the best plasma performance, and realized H-mode alone in 2012. Combination of ICRF and LHW power injection generated the H-mode plasmas with various ELMy characteristics. The first successful application of the ICRF Heating in the D (He3) plasma was also achieved. The progress on ICRF heating, LHCD experiments and their application in achieving H-mode operation from last two years will be discussed in this report