Maltese national birth weight for gestational age centile values

The relevance of using literature derived birth weight for gestational age centile charts for the Maltese population is debatable. The study set out to develop national weight for gestational age centile charts and compare these to other populations. Method: Anonymised birth weight for gestational age data with relevant maternal and neonatal observations over the period 1995-2009 were obtained from national statistics. The formats were standardised and imported into an SQL database that enabled filtration for single live births and grouping by sex. The data was scrutinized manually for obvious keying errors. The best estimate of gestational age from the last menstrual period (LMP) and expected date of delivery (EDD) was selected using established guidelines. A Box-Cox gamma transform was used to fit the model and generate separate centile charts. The data was compared to previous birth weight data reported in Maltese newborns in previous decades and to data from other countries. Results: A total of 58,899 neonates were included in the study and birth weight for gestational age centile charts were generated between 23 and 42 weeks of gestation using Revolution R with VGAM. There has been a statistically significant gradual fall in mean birth weight in Maltese newborns over the last four decades. There are also statistically significant differences between the Maltese data and those from other countries. Conclusion: The observed differences make the use of national birth weight for gestational age centile charts desirable both for routine clinical assessment and epidemiological studies.peer-reviewe

Negative thermal expansion

Materials with a negative thermal expansion coefficient contract when heated and expand when cooled. This paper reviews mechanisms of how this unusual property can be achieved at the molecular and macroscopic level. Some applications of this unusual property are also discussed.peer-reviewe

A system with adjustable positive or negative thermal expansion

We analyse the anisotropic thermal expansion properties of a two-dimensional structurally rigid construct made from rods of different materials connected together through hinges to form triangular units. In particular, we show that this system may be made to exhibit negative thermal expansion coefficients along certain directions or thermal expansion coefficients that are even more positive than any of the component materials. The end product is a multifunctional system with tunable thermal properties that can be tailor-made for particular practical applications.peer-reviewe

A survey of trends and motivations regarding Communication Service Providers' metro area network implementations

Relevance of research on telecommunications networks is predicated upon the implementations which it explicitly claims or implicitly subsumes. This paper supports researchers through a survey of Communications Service Providers current implementations within the metro area, and trends that are expected to shape the next-generation metro area network. The survey is composed of a quantitative component, complemented by a qualitative component carried out among field experts. Among the several findings, it has been found that service providers with large subscriber base sizes, are less agile in their response to technological change than those with smaller subscriber base sizes: thus, copper media are still an important component in the set of access network technologies. On the other hand, service providers with large subscriber base sizes are strongly committed to deploying distributed access architectures, notably using remote access nodes like remote OLT and remote MAC-PHY. This study also shows that the extent of remote node deployment for multi-access edge computing is about the same as remote node deployment for distributed access architectures, indicating that these two aspects of metro area networks are likely to be co-deployed.Comment: 84 page

Hepatic VLDL secretion : DGAT1 determines particle size but not particle number, which can be supported entirely by DGAT2

We investigated whether, in view of its activity being expressed on both aspects of the endoplasmic reticulum (ER; dual membrane topology), diacylglycerol acyltransferase 1 (DGAT1) plays a distinctive role in determining the triglyceride (TAG) content of VLDL particles secreted by the liver. Mice in which the DGAT1 gene was specifically ablated in hepatocytes (DGAT1-LKO mice) had the same number of VLDL particles (apoB concentration) in the plasma 1 h after Triton 1339 treatment, but these particles were approximately half the size of VLDL particles secreted by control mice and had a proportionately decreased content of TAG, with normal cholesterol and cholesteryl ester contents. Analyses of purified microsomal fractions prepared from 16 h fasted control and DAGT1-LKO mice showed that the TAG/protein ratio in the ER was significantly lower in the latter. Electron micrographs of these livers showed that those from DGAT1-LKO mice did not show the increased lipid content of the smooth ER shown by control livers. The effects of DGAT1- and DGAT2-specific inhibitors on apoB secretion by HepG2 cells showed that DGAT1 is not indispensable for apoB secretion and demonstrated redundancy in the ability of the two enzymes to support apoB secretion. Therefore, our findings show that DGAT1 is essential for the complete lipidation and maturation of VLDL particles within the lumen of the ER, consistent with its dual topology within the ER membrane. In the mouse, DGAT2 can support apoB secretion (particle number) even when TAG availability for full VLDL lipidation is restricted in the absence of DGAT1