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Hexagonal SiGe-2H has been recently shown to have a direct bandgap, and holds the promise to be compatible with silicon technology. Hexagonal Si and Ge have been grown on an epitaxial lattice matched template consisting of wurtzite GaP and GaAs, respectively. Here, we present the growth of hexagonal Si and SiGe nanowire branches grown from a wurtzite stem by the vapor−liquid−solid growth mode, which is substantiated by in situ transmission electron microscopy. We show that the composition can be tuned through the whole range of stoichiometry from Si to Ge, and the possibility to realize Si and SiGe heterostructures in these branches.

Background The World Health Organization's main strategy to reduce health inequalities in adulthood is preventing socioeconomic inequalities in early childhood. Yet, little is known about how children's socioeconomic position (SEP) shapes their development over time. Therefore, we investigated trajectories of socioeconomic inequality in early child development. Methods Data (n = 5104) was used from Generation R, a prospective population-based cohort in The Netherlands. SEP inequalities (defined by maternal education) in trajectories of internalizing and externalizing problems (mother reported Child Behavior Checklist at 1.5, 3, 5, and 9 years), and of language and motor development (mother reported Child Development Inventory at 0.5, 1, 1.5, 2, 3 and 4 years) were estimated using linear mixed models with standardized scores at each time point. Results Low SEP children had more internalizing (B = 0.72, 95%CI=0.51;0.95) and externalizing (B = 0.25, 95%CI=0.10;0.40) problems at 1.5 years, but better language skills at 1 year (B = 0.50, 95%CI=0.36;0.64), and better fine (B = 0.26, 95%CI=0.12;0.40) and gross motor (B = 0.40, 95%CI=0.25;0.55) skills at 0.5 years of age than high SEP children. For internalizing and externalizing problems, inequalities decreased over time. The low SEP advantage regarding language scores reversed in early childhood, and at 4 years of age, low SEP children (B=-0.38, 95%CI=-0.61;-0.15) had substantially worse language skills than high SEP children. For motor skills, the low SEP advantage at baseline decreased over time and disappeared around 4 years. Conclusions Socioeconomic inequalities in early child development differ by developmental domain: whereas inequalities in problem behavior and motor skills decreased over time, inequalities in language development increased. This indicates that low SEP children are already at a cognitive disadvantage before entering primary education, providing further evidence that interventions are needed before the age of 4. Key messages We investigated trajectories of socioeconomic inequality in early child development within a Dutch prospective birth cohort. Results showed that socioeconomic inequalities in child development decreased over time for emotional, behavioral and motor development, but increased for cognitive development.

Direct band gap III-V semiconductors, emitting efficiently in the amber-green region of the visible spectrum, are still missing, causing loss in efficiency in light emitting diodes operating in this region, a phenomenon known as the "green gap". Novel geometries and crystal symmetries however show strong promise in overcoming this limit. Here we develop a novel material system, consisting of wurtzite Al

Group IV semiconductor optoelectronic devices are now possible by using strain-free direct band gap GeSn alloys grown on a Ge/Si virtual substrate with Sn contents above 9%. Here, we demonstrate the growth of Ge/GeSn core/shell nanowire arrays with Sn incorporation up to 13% and without the formation of Sn clusters. The nanowire geometry promotes strain relaxation in the Ge

Thanks to their uniqueness, nanowires allow the realization of novel semiconductor crystal structures with yet unexplored properties, which can be key to overcome current technological limits. Here we develop the growth of wurtzite GaP/In

Background: Hypoxia is a negative prognostic factor and this study investigated the relationship between hypoxia, hypoxia inducible factor 1 (HIF-1) and AKT signaling in head and neck squamous cell carcinoma (HNSCC) and non-small-cell lung cancer (NSCLC). Results/methodology: pAKT was induced by hypoxia (0.5% O2) in a part of HNSCC (3/4) and squamous (2/3) and adenocarcinoma (1/3) NSCLS lines. AKT-inhibitor MK-2206 reduced hypoxic HIF-1 signaling in most HNSCC cell lines. This reduction did not correlate with hypoxic induction of pAKT or with sensitivity to MK-2206 under hypoxia. Patient biopsies revealed a hypoxia-induced expression pattern of pAKT in HNSCC (n = 16), which was not observed in squamous cell (n = 34) or adenocarcinoma (n = 41) NSCLC. Conclusion: The interaction between hypoxia, HIF-1 and AKT signaling varies between tumor types and histologies, which could significantly affect response to targeted therapies., Lay abstract: Hypoxia is the result of an imbalance between oxygen delivery and oxygen consumption, and hypoxic areas are a common feature in solid tumors, including head and neck and lung cancer. Hypoxia activates various signaling pathways that enhance the survival of tumor cells (e.g., HIF-1 and AKT) and is, therefore, an inherent negative factor for outcome. In this study, we show that the interaction between hypoxia and these pathways varies widely between tumor types and histologies. This variation could significantly affect response to treatments targeting hypoxia or these signaling pathways.

BACKGROUND: Mutations in the BRCA1 or BRCA2 genes are responsible for up to 95% of hereditary ovarian cancer cases. Both genes function as tumour suppressor genes, and development of a cancer is thought to require an accumulation of somatic genetic events in addition to the inherited germline predisposition. It is unknown whether these somatic events in BRCA associated ovarian cancer are similar to or distinct from those in sporadic cases. The most frequent somatic genetic event in ovarian cancer is a mutation of the p53 gene. AIM: To study the role of p53 in hereditary ovarian cancer, by analysing accumulation of the p53 protein in ovarian cancers which occurred in BRCA1 or BRCA2 germline mutation carriers and comparing the results with a panel of ovarian cancers from patients who tested negative for both BRCA1 and BRCA2. METHODS: The study group consisted of 39 ovarian cancer patients in whom a BRCA mutation had been confirmed previously. p53 Immunohistochemistry was performed on archival tissue using a standard microwave antigen retrieval technique. The rate of p53 accumulation was compared with 40 ovarian cancer cases who tested negative for BRCA1 and BRCA2 germline mutations. RESULTS: P53 Accumulation was similar in BRCA related ovarian cancers and BRCA negative controls. Overall 27 of 39 BRCA1 or BRCA2 positive cases (69%) had evidence of p53 accumulation, compared with 24 of 40 invasive ovarian cancer cases (60%) which tested negative for BRCA1 and BRCA2 germline mutations. BRCA1 related ovarian cancers showed p53 accumulation in 22 of 30 cases (73%); p53 accumulation was present in five of nine BRCA2 related ovarian cancers. CONCLUSIONS: In addition to germline BRCA1 and BRCA2 mutations, somatic p53 alterations leading to p53 accumulation are an important event in hereditary ovarian cancer and are as frequent as in non-BRCA-related ovarian cancer.

Background: Kinases downstream of growth factor receptors have been implicated in radioresistance and are, therefore, attractive targets to improve radiotherapy outcome in head and neck squamous cell carcinoma (HNSCC) patients. Methods: An antibody-based array was used to quantify the expression levels of multiple phospho-kinases involved in growth factor signaling in nine untreated or irradiated HNSCC lines. Radiosensitivity was assessed with clonogenic cell survival assays and correlated with the expression levels of the phospho-kinases. Inhibitors of the kinases that were associated with radiosensitivity were tested for their ability to increase radiosensitivity in the 3 most radioresistant HNSCC lines. Results: The basal expression of phosphorylated Yes, Src and STAT5A, and the expression after radiotherapy of phosphorylated AKT, MSK1/2, Src, Lyn, Fyn, Hck, and STAT6, were correlated with radiosensitivity in the panel of HNSCC lines. In combination with radiotherapy, inhibitors of AKT, p38 and Src Family Kinases (SFK) were variably able to reduce survival, whereas MEK1/2, STAT5 and STAT6 inhibition reduced survival in all cell lines. The combined effect of radiotherapy and the kinase inhibitors on cell survival was mostly additive, although also supra-additive effects were observed for AKT, MEK1/2, p38 and STAT5 inhibition. Conclusions: Kinases of the AKT, MAPK, STAT and SFK pathways correlated with radiosensitivity in a panel of HNSCC lines. Particularly inhibitors against MEK1/2, STAT5 and STAT6 were able to decrease survival in combination with radiotherapy. Hence, inhibitors against these kinases have the potential to improve radiotherapy outcome in HNSCC patients and further research is warranted to confirm this in vivo.

Background Only a minority of cancer patients benefits from the combination of EGFR-inhibition and radiotherapy in head and neck squamous cell carcinoma (HNSCC). A potential resistance mechanism is activation of EGFR and/or downstream pathways by stimuli in the microenvironment. The aim of this study was to find molecular targets induced by the microenvironment by determining the in vitro and in vivo expression of proteins of the EGFR-signaling network in 6 HNSCC lines. As hypoxia is an important microenvironmental parameter associated with poor outcome in solid tumors after radiotherapy, we investigated the relationship with hypoxia in vitro and in vivo. Methods Six human HNSCC cell lines were both cultured as cell lines (in vitro) and grown as xenograft tumors (in vivo). Expression levels were determined via western blot analysis and localization of markers was assessed via immunofluorescent staining. To determine the effect of hypoxia and pAKT-inhibition on cell survival, cells were incubated at 0.5% O2 and treated with MK-2206. Results We observed strong in vitro-in vivo correlations for EGFR, pEGFR and HER2 (rs=0.77, p=0.10, rs=0.89, p=0.03) and rs=0.93, p=0.02, respectively), but not for pAKT, pERK1/2 or pSTAT3 (all rs0.30). In vivo, pAKT expression was present in hypoxic cells and pAKT and hypoxia were significantly correlated (rs=0.51, p=0.04). We confirmed in vitro that hypoxia induces activation of AKT. Further, pAKT-inhibition via MK-2206 caused a significant decrease in survival in hypoxic cells (p Conclusions These data suggest that (p)EGFR and HER2 expression is mostly determined by intrinsic features of the tumor cell, while the activation of downstream kinases is highly influenced by the tumor microenvironment. We show that hypoxia induces activation of AKT both in vitro and in vivo, and that hypoxic cells can be specifically targeted by pAKT-inhibition. Targeting pAKT is thus a potential way to overcome therapy resistance induced by hypoxia and improve patient outcome.

Ces contributions anisotropes de surface et de volumes dues a l'introduction d'une marche se revelent du meme ordre de grandeur pour une interface Si−SiO 2 . On se fonde sur l'abaissement de la symetrie de la surface par les marches et par l'augmentation apparente de la susceptibilite non lineaire aux limites des marches

The formation of parietal endoderm (PE) from primitive endoderm (PrE) immediately after implantation of the early mouse embryo can be seen as the earliest example of an epithelio-mesenchyme transition (EMT) in murine development. Since EMT and EMI (epithelium-mesenchyme interactions) are at the very heart of morphogenesis, identifying molecular mechanisms governing these processes is of utmost importance. An excellent in vitro model system to study PE formation, i.e. F9 embryonal carcinoma cells, is available to this end. In the present paper we review our own recent results and those of others using these cells, and present our current view on the molecular mechanisms involved in PE formation.

The blocking temperature T(B) has been determined as a function of the antiferromagnetic layer thickness in the Fe3O4/CoO exchange biased system. For CoO layers thinner than 50 A, T(B) is reduced below the Néel temperature T(N) of bulk CoO (291 K), independent of crystallographic orientation or film substrate ( alpha-Al2O3, SrTiO3, and MgO). Neutron diffraction studies show that T(B) does not track the CoO ordering temperature and, hence, that this reduction in T(B) does not arise from finite-size scaling. Instead, the ordering temperature of the CoO layers is enhanced above the bulk T(N) for layer thicknesses approximately less than or equal to 100 A due to the proximity of magnetic Fe3O4 layers.

Vanadium dioxide (VO2 ) exhibits a reversible semiconductor-to-metal phase transition around 341 K. The low temperature monoclinic P21 /c structure transforms into the tetragonal P42 /mnm rutile structure. The associated sharp changes in optical and electrical properties are used in various thin film switching devices. The present paper describes a study on the optical and structural changes during the synthesis of VO2 thin films using Infra-Red (IR) reflectance spectroscopy and Transmission Electron Microscopy (TEM).The synthesis was derived from a sol-gel process by Guzman et al. Solutions of vanadyl isopropoxide (VO(OC3 H7)3 ) in n-propanol were spin-coated on a Si wafer provided with 300 nm thermal oxide. Subsequently, the wafer was transferred to an oven and heated to 773 K in a reducing H2/N2 atmosphere using a heating rate of 5 K/min. After a variable time (Δt) at 773 K, the samples were cooled down to room temperature.Figure 1 shows the IR reflectance of thin (∽50 nm) VOx films on oxidised Si at λ,=3 μm and an angle of incidence ϕ of 30°.

The appearance of well defined steps on vicinal Si(111) surfaces has a very pronounced effect on the rotational anisotropy of the Second Harmonic Generation from these surfaces. This effect can be explained by the lowering of the surface symmetry and an enhancement of the nonlinear susceptibility at these steps. By modifying the surface in this way, surface and bulk contributions to the SHG could be determined separately.

The construction and performance of a simple atomic-beam apparatus, used only for the absolute frequency stabilisation of the dye laser, is described. The laser frequency is stabilised on the maximum of the near-Doppler-free fluorescence signal of a Ne* atomic beam crossing the laser beam. Different detection techniques to optimise the signal-to-background ratio have been investigated. Optical fibres are used to transport the laser beam to the atomic-beam apparatus, which is advantageous in comparison with direct transport by mirrors. Using a computer-controlled stabilisation loop a flexible stabilisation scheme is obtained which gives the possibility of performing measurements at slightly shifted frequencies and to interrupt the computer-controlled main experiment after detection of a mode hop.

This study describes all the versions of the New Testament made before A.D. 1000, providing an account of the scholarly investigation, textual analysis and progress of research on each version.