Childhood obesity is a common concern across global cities and threatens sustainable urban development. Initiatives to improve nutrition and encourage physical exercise are promising but are yet to exert significant influence on prevention. Childhood obesity in London is associated with distinct ethnic and socio-economic patterns. Ethnic inequalities in health-related behaviour endure, underpinned by inequalities in employment, housing, access to welfare services, and discrimination. Addressing these growing concerns requires a clearer understanding of the socio-cultural, environmental and economic contexts of urban living that promote obesity. We explore opportunities for prevention using asset based-approaches to nutritional health and well-being, with a particular focus on adolescents from diverse ethnic backgrounds living in London. We focus on the important role that community engagement and multi-sectoral partnership play in improving the nutritional outcomes of London's children. London's children and adolescents grow up in the rich cultural mix of a global city where local streets are characterised by diversity in ethnicities, languages, religions, foods, and customs, creating complex and fluid identities. Growing up with such everyday diversity we argue can enhance the quality of life for London's children and strengthen their social capital. The Determinants of young Adult Social well-being and Health longitudinal study of about 6500 of London's young people demonstrated the positive impact of cultural diversity. Born to parents from over a hundred countries and exposed to multi-lingual households and religious practices, they demonstrated strong psychological resilience and sense of pride from cultural straddling, despite material disadvantage and discrimination. Supporting the potential contribution of such socio-cultural assets is in keeping with the values of social justice and equitable and sustainable development. Our work signals the importance of community engagement and multisectoral partnerships, involving, for example, schools and faith-based organisations, to improve the nutrition of London's children.

This work aims at attaining a more complete understanding of the principles governing resistive contrast imaging (RCI) of copper/low-k interconnects used for dielectric breakdown studies in a nanoprober scanning electron microscope (SEM) system. RCI is employed in such in situ dielectric breakdown studies to facilitate the localization of interconnect defect sites related to various stages in the degradation process of the low-k dielectric material. This work shows that RCI is suitable for detecting high-resistance sites, like opens, in copper/low-k interconnects. Moreover, RCI demonstrates potential in locating defects that lie deep in the test structure and are, thus, not detectable by SEM. A model is also proposed to explain the formation of RCI images of specific interconnect test structures with complex layout.

Electronic devices capable of performing in extreme mechanical conditions such as stretching, bending, or twisting will improve biomedical and wearable systems. The required capabilities cannot be achieved with conventional building geometries, because of structural rigidity and lack of mechanical stretchability. In this article, a zigzag-patterned structure representing a stretchable interconnect is presented as a promising type of building block. In situ experimental observations on the deformed interconnect are correlated with numerical analysis, providing an understanding of the deformation and failure mechanisms. The experimental results demonstrate that the zigzag-patterned interconnect enables stretchability up to 60% without rupture. This stretchability is accommodated by in-plane rotation of arms and out-of-plane deformation of crests. Numerical analysis shows that the dominating failure cause is interfacial in-plane shear stress. The plastic strain concentration at the arms close to the crests, obtained by numerical simulation, agrees well with the failure location observed in the experiment.

This paper focuses on the measurement of material properties of micro and nano-electromechanical systems. Two different methods are discussed: electrical or optical measurements of the resonance frequency, and measurements of the Raman frequency shift. The main focus of this paper is on challenges and pitfalls related to the use of these techniques for the study of MEMS and NEMS.

Large area deformable macroelectronics, such as flexible display, smart bandage, electronic textile, have to withstand various modes of deformation (e.g., bending, twisting and stretching). Such electronic systems usually are composed of inorganic parts with limited deformability, and organic parts which can sustain large deformations. Because of the elastic nature of elastomers, these materials are often used as substrates for the specific applications mentioned above. In order to fulfill the demand of deformability, many concepts have been developed. One of these concepts consists of small rigid islands with active devices or individual thin chips which are interconnected by thin metal conductor lines. All rigid components are placed on the small islands to ensure that the strains acting on these brittle components are small when the structure is subjected to a large deformation. Since the thin conductor lines have to withstand all these deformations, a proper structural design is necessary to avoid losing structural integrity and electrical functionality during this deformation. Several technologies have been proposed in recent years, such as in-plane patterned metal conductors, out-of-plane wrinkling metal films, and conductive polymers or liquid alloys. It has been reported that by depositing a thin metal strip with a thickness of few nanometers on an elastomeric substrate, the elongation of the metal can go up to 50% while the strip remains conductive. Upon large strain, the elastic deformation of the elastomeric substrate causes local debondings of the metal film coevolving with strain localizations. Thanks to this coevolved process, even a �straight� line, deposited on a polymer substrate, is stretchable. However, a drawback of this unique characteristic is that the resistance of the thin metal film changes with elongation, which might be a disadvantage for certain applications. Another approach for having a stable resistance is to use bulk metal conductors. Compared to a freestanding bulk metal straight line which ruptures at strains of 1%˜2%, an in-plane patterned horseshoe metal conductor can be stretched up to 100% with a stable resistance before electrical failure. This paper demonstrates a novel in-plane patterned zigzag structure, with resistance independent of elongation before metal rupture, which can be stretched beyond 40%. The advantage compared to the horseshoe is that due to the geometrical design, the in-plane zigzag structural interconnects can be applied in a fine pitch microelectronic device. The experimental observations by both scanning electron microscopy micrographs and resistance measurements show that there is no significant local necking in either the transverse or the thickness direction at the metal breakdown area. Micrographs and simulation results show that a debonding occurs due to the local twisting of a metal interconnect, out-of-plane peeling and strain localized at the crest of a zigzag structure.

Wafer thinning, one of the key enabling techniques for 3D integration, is widely studied due to its impact on Si breakage strength. However, most studies only focused on the average strength, without checking the failure mechanisms. This may result in misleading conclusions and the mechanism of breakage is still ambiguous. In this paper, the mechanical strength of wafers that were thinned using different methods [rough grinding(RG), fine grinding(FE), plasma etching(PE), chemical mechanical polishing(CMP)] was evaluated statistically and through failure analysis. The results provide the industry guidance on their wafer thinning strategy. Si wafers were thinned down to 300μm by different thinning techniques: only RG; RG+FG; RG+FG+10μm CMP and RG+FG+10μm PE. Next the samples were diced into strips and the strength was tested using a 4-point bending test. The breakage strength of the dies was plotted in Weibull graphs and on wafer maps. Both RG and PE samples showed a strong bimodal distribution. On the other hand, both FG and CMP wafers showed a monomodal behaviour. This observation was unexpected and until now never reported in literature. The RG wafer has large surface grooves and is the weakest one, as expected. The bimodal distribution of the strength of RG-dies could be related to the direction of the grinding marks on the surface (along width or length of the Si strips). There is a direct correlation with the position of the dies on the wafer and the bimodal distribution. Samples with lines perpendicular to the tensile stress (along the width of the strips) are more vulnerable than the rest. The fracture on these samples propagates vertically from the ground surface, along the {110} plane. The others are stronger and break along the {111} plane. FG improves both the surface roughness and the strength compared to RG. The Weibull curve, with a monomodal behavior, shifts to a higher breakage strength, indicating that the effect of the grooves on the breakage strength is removed by FG. After CMP, the strength raises 17% compared to FG-Si due to the removal of surface roughness. Similarly, PE increases the average strength by 15% from FG. However, the Weibull plot shows that after PE, there is again a bimodal failure distribution. The weaker one falls on top of the FG distribution and the stronger one mixes up with the CMP. This indicates that although a large fraction of these samples have a similar strength as CMP, but some parts still have defects, probably local roughness related, that serve as easy initiation of fracture. This study shows that the orientation of the grinding marks plays an important role in determining the fracture plane and thus the strength. FG can efficiently remove this effect. We also showed for the first time that even after PE there is a bimodal strength distribution. Part of the dies has the same strength as the ones after CMP, but part of the population still has a lower strength.

The most important tool for obtaining insight into the function of genes is the use of mutant model organisms. Homologous recombination in embryonic stem cells allows the systematic production of mouse mutants for any gene that has been cloned. Gene trap strategies have been designed to interrupt even unknown genes which are tagged by the inserted vector and can be characterised structurally and functionally. Complementary to such 'gene-driven' approaches, 'phenotype-driven' approaches are necessary to identify new genes or gene products through a search for mutants with specific defects, uncovering the function of genetic pathways in physiological and pathological processes. Mutagenesis using the alkylating agent N-ethyl-N-nitrosourea (ENU) is a powerful approach for the production of such mouse mutants. Since ENU induces mainly point mutations in premeiotic spermatogonia, this strategy allows the production of multiple alleles of a particular gene, which is pivotal for a fine tuned analysis of its function.

In this paper, the different applications of Raman spectroscopy for the study of thin films is briefly discussed, using examples from microelectronics. Special attention is given to the application of micro-Raman spectroscopy for the measurement of local stress in and near films.

Local mechanical stress introduced in the silicon substrate during the successive steps of poly-buffered local isolation of MOS integrated circuits is studied with micro-Raman spectroscopy. It is shown that the magnitude and the local variation of the stress is highly affected by the different processing steps. After deposition of the nitride mask, the stress can be described as caused by an edge-force. Field oxidation reduces the mask-induced stress but introduces thermal stress from the field oxide. Also the formation of the bird's beak gives rise to additional local tensile stress, especially at the tip of the bird's beak. Removal of the nitride mask results in a partial relaxation: the stress caused by the bird's beak relaxes. In this last stage of the isolation process, the stress image is mostly determined by the field oxide.

Non-uniform hot-carrier degradation in n-channel polycide-gate MOSFET's with different thicknesses of the poly-Si film, and in p-channel polycide-gate MOSFET's with TiSi2- or CoSi2-gate-silicide, is studied. The n-MOSFET's with the thinnest poly-Si film, show an increased interface trap generation, while the influence of the gate-silicide material on the degradation behaviour of the p-MOSFET's is found to be very small. The results are evaluated in terms of the effect of mechanical stress on the degradation characteristics: favourable for compressive mechanical stress and unfavourable for tensile stress. A correlation with stress measurements by micro-Raman spectroscopy is made.

Non-uniform hot-carrier degradation in n-channel polycide-gate MOSFET's with different thicknesses of the poly-Si film, and in p-channel polycide-gate MOSFET's with TiSi2- or CoSi2-gate-silicide, is studied. The n-MOSFET's with the thinnest poly-Si film, show an increased interface trap generation, while the influence of the gate-silicide material on the degradation behaviour of the p-MOSFET's is found to be very small. The results are evaluated in terms of the effect of mechanical stress on the degradation characteristics: favourable for compressive mechanical stress and unfavourable for tensile stress. A correlation with stress measurements by micro-Raman spectroscopy is made.

Micro Raman spectroscopy (RS) is used to study the crystalline quality and the stresses in the thin superficial silicon layer of Silicon-On-Insulator (SO) materials. Results are presented for SIMOX (Separation by IMplanted OXygen) and ZMR (Zone Melt Recrystallized) substrates. Both as implanted and annealed SIMOX structures are investigated. The results from the as implanted structures are correlated with spectroscopic ellipsometry (SE) and cross-section transmission electron microscopy (TEM) analyses on the same material. Residual stress in ZMR substrates is studied in low- and high temperature gradient regions.