Well-defined second-order nonlinear optical polymers by controlled radical polymerization,via multifunctional macromolecular chain transfer agent: Design,synthesis, and characterizations

To address the issue of the aggregation in second-order nonlinear optical (NLO) polymers we developed an approach based on the synthesis of a multifunctional macromolecular chain transfer agent. The controlled monomer insertion polymerization into the main chain by a ‘reversible addition-fragmentation chain transfer’ (RAFT) mechanism allows the spatial arrangement of the NLO chromophores along the polymeric chain in order to obtain sequence-ordered polymers. In a first step, a novel trithiocarbonate based macroinitiator containing the disperse red 19 (DR19) units in the main chain was synthesized by polycondensation; in a second step, this polymeric precursor was applied to the synthesis of a sequentially ordered polymer by controlled insertion radical polymerization of styrene. Size exclusion chromatography (SEC), nuclear magnetic resonance (NMR) data revealed that, (i) for the first time, polystyrenes (PS) bearing DR19 dyes covalently bounded were obtained, and (ii) both the insertion reaction and the length of the polystyrene segments were accurately controlled. Whatever the incorporated dye amount, all the copolymers were soluble in common solvents. Second-order optical nonlinearity in corona-poled thin films was evaluated, and second harmonic coefficients up to 80 pm/V were determined for loading ratio lower than 10 wt-% (DR19/PS). This approach opens up opportunities for the incorporation of more efficient chromophores even in apolar matrices.     

Socioeconomic impacts of heat transfer research

Heat transfer research affects almost every sector of the economy, yet its impacts have not been well studied or communicated to date. To address this issue, this article evaluates recent heat transfer research trends and which parts of the economy are likely to be affected by it. Analysis is done through keywords in heat transfer journals, US NSF awards, US patents, and trends in US economic sectors. This study indicates that if heat transfer research helps to attain a 10% conversion efficiency gain in all relevant sectors of the US economy, ~ 110 billion dolars of annual value added could be generated.     

Interaction between Metformin,Folate and Vitamin B12 and the Potential Impact on Fetal Growth and Long-Term Metabolic Health in Diabetic Pregnancies

Metformin is the first-line treatment for many people with type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM) to maintain glycaemic control. Recent evidence suggests metformin can cross the placenta during pregnancy, thereby exposing the fetus to high concentrations of metformin and potentially restricting placental and fetal growth. Offspring exposed to metformin during gestation are at increased risk of being born small for gestational age (SGA) and show signs of ‘catch up’ growth and obesity during childhood which increases their risk of future cardiometabolic diseases. The mechanisms by which metformin impacts on the fetal growth and long-term health of the offspring remain to be established. Metformin is associated with maternal vitamin B₁₂ deficiency and antifolate like activity. Vitamin B₁₂ and folate balance is vital for one carbon metabolism, which is essential for DNA methylation and purine/pyrimidine synthesis of nucleic acids. Folate:vitamin B₁₂ imbalance induced by metformin may lead to genomic instability and aberrant gene expression, thus promoting fetal programming. Mitochondrial aerobic respiration may also be affected, thereby inhibiting placental and fetal growth, and suppressing mammalian target of rapamycin (mTOR) activity for cellular nutrient transport. Vitamin supplementation, before or during metformin treatment in pregnancy, could be a promising strategy to improve maternal vitamin B₁₂ and folate levels and reduce the incidence of SGA births and childhood obesity. Heterogeneous diagnostic and screening criteria for GDM and the transient nature of nutrient biomarkers have led to inconsistencies in clinical study designs to investigate the effects of metformin on folate:vitamin B₁₂ balance and child development. As rates of diabetes in pregnancy continue to escalate, more women are likely to be prescribed metformin; thus, it is of paramount importance to improve our understanding of metformin’s transgenerational effects to develop prophylactic strategies for the prevention of adverse fetal outcomes.     

Electroless thin film CoNiFe-B alloys for integrated magnetics on Si

Electroless magnetic thin films have been deposited from borane-based baths suitable for use in integrated magnetics on Si applications. The baths were developed for compatibility with standard photoresist for microfabrication of integrated magnetics on Si. The specific formulations, which differ from those reported previously, yield uniform, high saturation magnetisation (up to 2.15 T) deposits with low coercivity (<2 Oe). The resistivity of the film can be increased to minimise eddy current losses by using higher dimethylamine borane (DMAB) content or the inclusion of a second reducing agent, hypophosphite, to facilitate phosphorus codeposition of up to 7 at.%. The Ni content in the plating bath has been shown to exert significant influence over the composition, deposition rate and coercivity. XRD analysis suggests that the deposits consist of nanocrystalline phase with grains <20 nm. Such small grains are consistent with the observed low coercivity of the deposits.     

On measuring forgery quality in online signatures

This work proposes a novel measure to quantify the quality of a skilled forgery sample in the online signature framework. Such a quality measure is constructed by adapting our former Personal Entropy to the context of skilled forgeries production. For validation, we confront our quality measure to several types of skilled forgeries (static, dynamic, professional) captured on different acquisition platforms. Indeed, four databases are exploited: MCYT-100, Philips database, BioSecure data subsets DS2 and DS3. We prove the effectiveness of our quality measure to quantify the quality of all types of skilled forgeries available with regards to the performance of three classifiers: a Dynamic Time Warping, a Hidden Markov models and a Gaussian Mixture Model.     

Image analysis of histological features in molar pregnancies

Molar pregnancy (also known as hydatidiform mole, hydatid mole, gestational trophoblastic disease) represents forms of abnormal conception caused by defective fertilisation resulting in excess expression of paternal genes in placental tissue. There are two forms of hydatidiform mole: complete (diploid androgenetic) and partial (paternal triploid), the distinction between which is important for determining appropriate prognosis and management of patients. Both complete and partial hydatidiform moles are associated with increased risk of development of malignant gestational trophoblastic tumours, the risk being much greater for complete hydatidiform moles. Whilst in most cases the diagnosis of these moles can be reliably achieved on morphological histological assessment, these represent a continuing diagnostic problem for histopathologists since in early pregnancy complete hydatidiform moles, partial hydatidiform moles and non-molar hydropic miscarriages may be difficult to distinguish.In this paper, we propose a computational image analysis approach guided by the knowledge of expert pathologists in identifying essential distinguishing morphological criteria. The approach, which combines Fuzzy C-Means clustering with hue, saturation and value colour space, shows promising results as it is able to classify successfully the villi into appropriate regions, namely trophoblast and stroma, and extract areas of blood. However, because of the marked variations in size, shape and outline of the villi, and trophoblast proliferation, both within and between cases, the analysis shows that there is no single criteria which can reliably classify these products of conception and a combination of criteria is required.