A light-hole exciton in a quantum dot

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Anisotropic Confinement, Electronic Coupling and Strain Induced Effects Detected by Valence-Band Anisotropy in Self-Assembled Quantum Dots

A method to determine the effects of the geometry and lateral ordering on the electronic properties of an array of one-dimensional self-assembled quantum dots is discussed. A model that takes into account the valence-band anisotropic effective masses and strain effects must be used to describe the behavior of the photoluminescence emission, proposed as a clean tool for the characterization of dot anisotropy and/or inter-dot coupling. Under special growth conditions, such as substrate temperature and Arsenic background, 1D chains of In0.4Ga0.6 As quantum dots were grown by molecular beam epitaxy. Grazing-incidence X-ray diffraction measurements directly evidence the strong strain anisotropy due to the formation of quantum dot chains, probed by polarization-resolved low-temperature photoluminescence. The results are in fair good agreement with the proposed model

Phosphoproteomics-Based Modeling Defines the Regulatory Mechanism Underlying Aberrant EGFR Signaling

BACKGROUND: Mutation of the epidermal growth factor receptor (EGFR) results in a discordant cell signaling, leading to the development of various diseases. However, the mechanism underlying the alteration of downstream signaling due to such mutation has not yet been completely understood at the system level. Here, we report a phosphoproteomics-based methodology for characterizing the regulatory mechanism underlying aberrant EGFR signaling using computational network modeling. METHODOLOGY/PRINCIPAL FINDINGS: Our phosphoproteomic analysis of the mutation at tyrosine 992 (Y992), one of the multifunctional docking sites of EGFR, revealed network-wide effects of the mutation on EGF signaling in a time-resolved manner. Computational modeling based on the temporal activation profiles enabled us to not only rediscover already-known protein interactions with Y992 and internalization property of mutated EGFR but also further gain model-driven insights into the effect of cellular content and the regulation of EGFR degradation. Our kinetic model also suggested critical reactions facilitating the reconstruction of the diverse effects of the mutation on phosphoproteome dynamics. CONCLUSIONS/SIGNIFICANCE: Our integrative approach provided a mechanistic description of the disorders of mutated EGFR signaling networks, which could facilitate the development of a systematic strategy toward controlling disease-related cell signaling

Attraction Basins as Gauges of Robustness against Boundary Conditions in Biological Complex Systems

One fundamental concept in the context of biological systems on which researches have flourished in the past decade is that of the apparent robustness of these systems, i.e., their ability to resist to perturbations or constraints induced by external or boundary elements such as electromagnetic fields acting on neural networks, micro-RNAs acting on genetic networks and even hormone flows acting both on neural and genetic networks. Recent studies have shown the importance of addressing the question of the environmental robustness of biological networks such as neural and genetic networks. In some cases, external regulatory elements can be given a relevant formal representation by assimilating them to or modeling them by boundary conditions. This article presents a generic mathematical approach to understand the influence of boundary elements on the dynamics of regulation networks, considering their attraction basins as gauges of their robustness. The application of this method on a real genetic regulation network will point out a mathematical explanation of a biological phenomenon which has only been observed experimentally until now, namely the necessity of the presence of gibberellin for the flower of the plant Arabidopsis thaliana to develop normally

Effect of an intensive lifestyle intervention on the prevalence of metabolic syndrome and its components among overweight and obese adults

AbstractBackgroundDespite the fact that up to a third of the global population has metabolic syndrome (MetS), it has been overlooked in clinical settings. This study assesses the impact of a physician-supervised nonsurgical weight management program on the prevalence of MetS and its key indicators.MethodsFour-hundred seventy-nine overweight and obese participants aged 19 years or older were included in a prospective longitudinal study. Changes in MetS and its key indicators were assessed using the binomial exact, chi-square and Wilcoxon signed-rank tests in an intent-to-treat study population. Differences in age strata were assessed using a generalized linear model.ResultsFifty-two percent of participants (n = 249) had MetS at baseline. Prevalence of MetS decreased steadily with significant changes from baseline observed at weeks 13 (31.8%, P &amp;lt; 0.0001), 26 (28.7%, P &amp;lt; 0.0012) and 39 (21.6%, P &amp;lt; 0.0002); changes from baseline were observed at week 52 as statistically significant (16.7%, P &amp;lt; 0.0012). Improvements in anthropometrics and levels of key indicators of MetS were observed throughout the study.ConclusionThese findings confirm that weight loss is inversely associated with prevalence of MetS and its key indicators among overweight and obese individuals. Future studies may benefit from a larger sample size and better retention (ClinicalTrials.gov ID: NCT03588117).</jats:sec