A Method of Comparing Differences in Tumour Growth Rates Applied to a Study of the Increasing Growth Capacity of Mouse Carcinomata

A method of comparing differences in growth rates of tumours in small groups of animals is described. A common slope can be fitted to the growth curves of a given tumour in a group of isogeneic animals. Differences between growth potentials can be demonstrated by comparing the common slope for a given tumour against that of another tumour (or the same tumour at a later stage of development)

Paediatric admissions to hospitals in the Cape Town Metro district: A survey

A point prevalence survey of 381 paediatric medical inpatients in the 11 public hospitals in Cape Town in November 2007 showed that 70% of them were in central hospitals, with 39.4% requiring level 3 (sub-specialist) care. Numbers of children in hospital and their levels of health care requirement did not vary by sub-district of residence. Seventy-seven per cent of patients were under 5 years of age; 5% were teenagers. Few patients changed level of care during admission, but 10% did not need to be in hospital at the time of review. Median length of stay was 4 days, with children with level 3 needs having the longest lengths of stay. An under-provision of level 1 beds was demonstrated. HIV infection had been identified in 12% of admissions. While children with level 3 problems were well catered for in terms of bed provision, level 1 and step-down/home care provision were deficient or inefficiently utilised

Ocean acidification of a coastal Antarctic marine microbial community reveals a critical threshold for CO2 tolerance in phytoplankton productivity

© 2017 Author. High-latitude oceans are anticipated to be some of the first regions affected by ocean acidification. Despite this, the effect of ocean acidification on natural communities of Antarctic marine microbes is still not well understood. In this study we exposed an early spring, coastal marine microbial community in Prydz Bay to CO2 levels ranging from ambient (343μatm) to 1641μatm in six 650 L minicosms. Productivity assays were performed to identify whether a CO2 threshold existed that led to a change in primary productivity, bacterial productivity, and the accumulation of chlorophyll a (Chl a) and particulate organic matter (POM) in the minicosms. In addition, photophysiological measurements were performed to identify possible mechanisms driving changes in the phytoplankton community. A critical threshold for tolerance to ocean acidification was identified in the phytoplankton community between 953 and 1140μatm. CO2 levels ≥1140μatm negatively affected photosynthetic performance and Chl a-normalised primary productivity (csGPP14C), causing significant reductions in gross primary production (GPP14C), Chl a accumulation, nutrient uptake, and POM production. However, there was no effect of CO2 on C VN ratios. Over time, the phytoplankton community acclimated to high CO2 conditions, showing a down-regulation of carbon concentrating mechanisms (CCMs) and likely adjusting other intracellular processes. Bacterial abundance initially increased in CO2 treatments ≥953μatm (days 3-5), yet gross bacterial production (GBP14C) remained unchanged and cell-specific bacterial productivity (csBP14C) was reduced. Towards the end of the experiment, GBP14C and csBP14C markedly increased across all treatments regardless of CO2 availability. This coincided with increased organic matter availability (POC and PON) combined with improved efficiency of carbon uptake. Changes in phytoplankton community production could have negative effects on the Antarctic food web and the biological pump, resulting in negative feedbacks on anthropogenic CO2 uptake. Increases in bacterial abundance under high CO2 conditions may also increase the efficiency of the microbial loop, resulting in increased organic matter remineralisation and further declines in carbon sequestration

Lung function in South African children with cystic fibrosis

Objective: To determine the pattern of lung function in stable cystic fibrosis (CF) patients and to investigate the relationship of abnormal lung function to demographic variables, CF genotype and pulmonary colonisation with Pseudomonas aeruginosa (PA)Design: A descriptive study done at the CF clinic at Red Cross War Memorial Children's Hospital in Cape Town.Methods: Data were recorded and pulmonary function testing (PFT) was performed in 42 CF patients.Results: 29 patients (69%) had mild disease,. while 11 (26%) and 2 (5%) had moderate and severe disease respectively. Twenty-four patients (57'%) demonstrated lower airway obstruction (LAO). Patients with moderate or severe disease were significantly older than those with mild disease (13.3 (3.7) years (mean (SD)) compared with 11.1 (3.0) years (t =2.1; P =OM)). PA colonisation status differed significantly with the pattern of lung function (X2 =6.6; P = 0.04) and severity of lung disease (X2=12.6; P =0.002.). Nine (35%) of the 26 patients tested before and after broncbodilator therapy showed a positive response.Conclusion: The majority of patients had mildly impaired or normal lung function, with LAO predominating. A minority of patients were bronchodilator-responsive. PA colonisation may be associated with the development of abnormal lung function and more severe pulmonary disease.

Localization of human breast-carcinoma xenografts using antibodies to carcinoembryonic antigen.

Affinity-purified antibodies to carcinoembryonic antigen (CEA) have been injected into immune-suppressed mice bearing xenografts of human breast tumours. It has been shown that the antibodies localized in the tumours but not in normal tissues. The degree of tumour localization correlates with the amount of tumour CEA, and is unaffected by levels of circulating CEA or CEA/anti-CEA immune complexes

Developing sexual competence? Exploring strategies for the provision of effective sexualities and relationships education

School-based sexualities and relationships education (SRE) offers one of the most promising means of improving young people's sexual health through developing 'sexual competence'. In the absence of evidence on whether the term holds the same meanings for young people and adults (e.g. teachers, researchers, policy-makers), the paper explores 'adult' notions of sexual competence as construed in research data and alluded to in UK Government guidance on SRE, then draws on empirical research with young people on factors that affect the contexts, motivations and outcomes of sexual encounters, and therefore have implications for sexual competence. These data from young people also challenge more traditional approaches to sexualities education in highlighting disjunctions between the content of school-based input and their reported sexual experience. The paper concludes by considering the implications of these insights for developing a shared notion of what SRE is trying to achieve and suggestions for recognition in the content and approaches to SRE.</p

Indentation-based characterization of creep and hardness behavior of magnesium carbon nanotube nanocomposites at room temperature

The time-dependent plastic deformation response of magnesium/carbon nanotube (CNT) nanocomposites containing 0.25, 0.5, and 0.75 vol% of carbon nanotubes is investigated through depth nanoindentation tests against monolithic pure magnesium in the present study. The Mg-CNT nanocomposite materials were successfully synthesized via a powder metallurgy technique coupled with microwave sintering followed by hot extrusion to produce 8-mm diameter, long solid bars. All depth-sensing indentation creep tests were conducted at ambient (room) temperature employing a diamond Berkovich pyramidal indenter. These tests are dual-stage, i.e., loading to a prescribed peak load of 50 mN, holding the peak load constant for a dwell period of 500 s, and finally unloading. Various strain rates of 0.01, 0.1, 1, and 10 s−1were performed to assess the effects of strain rate and dwell time on the ambient temperature creep response of the Mg-CNT nanocomposites. The outcomes of these tests are explained through material hardness, microstructure, the extent of CNT content in each material, and strain rate sensitivity. Upon analyzing the nanoindentation creep tests, the dominant creep mechanism at room temperature was found to be a dislocation creep mechanism. It is also found that CNTs increase the creep resistance of magnesium. Findings of this study can be used as a starting point for a high-temperature creep study on Mg-CNT nanocomposites. This paper is a continued study from our group on time-dependent plastic deformation of Mg nanocomposites (i.e., see Haghshenas et al., Journal of Composite Materials, https://doi.org/10.1177/0021998318808358). The short-term goal is to provide a compressive picture of the controlling creep mechanisms and their dependency upon, time, temperature, strain rate, volume fraction of the nanoparticles, and the type of the nanoparticles. Mg, in general, is a notorious material for high-temperature application; therefore, the long-term objective is to propose Mg nanocomposite as reliable replacements for Mg when lightweight and creep resistance are needed. However, to be able to confidently suggest such a replacement detailed understanding on the controlling phenomena, mention as short-term goals, are required

Assessment of the regioselectivity in the condensation reaction of unsymmetrical o-phthaldialdehydes with alanine

Funding: We would like to thank the EPSRC DTG at the University of St Andrews for funding.One approach for the synthesis of isoindolinones, a privileged bioactive heterocyclic core structure, involves a condensation reaction of o-phthaldialdehydes with a suitable nitrogen-containing nucleophile. This fascinating reaction is revisited here in the context of the use of o-phthaldialdehydes that contain additional substituents in the aromatic ring leading to a detailed analysis of the regioselectivity of the reaction. Eleven monosubstituted o-phthaldialdehydes were synthesised and reacted with alanine. The regioselectivity observed across the eleven substrates led to the design of a disubstituted substrate that reacted with very high control. A gram-scale reaction followed by esterification gave one major regioisomer in high yield. In addition, the regioselectivity observed on reaction of two novel monodeuterated substrates led to an increased mechanistic understanding.PostprintPeer reviewe