Spirobifluorene Dimers: Understanding How The Molecular Assemblies Drive The Electronic Properties

Spirobifluorene (SBF) is one of the most important scaffolds used in the design of organic semi-conductors (OSCs) for electronics. In recent years, among all the structures developed for these applications, SBF dimers have been highlighted due to their great potential in thermally activated delayed fluorescence and in phosphorescent organic light-emitting diodes. Attaching two SBF units generate 10 dimers, each possessing its own structural specificity, which in turn drives its electronic properties. These ten SBF dimers are gathered herein. Understanding how the molecular assembly determines the electronic properties has been one of the pillars of organic electronics. This is the goal of this article. As positional isomerism is a key tool to design OSCs, defining the design guidelines for the SBF scaffold appears of interest for the future of this building block. Herein, the importance of the two main parameters involved in the electrochemical and photophysical properties, namely the nature of the phenyl linkages and the steric congestion between the two SBF units is discussed. The combination of these two parameters drives the electronic properties but their respective weight is different as a function of the regioisomer involved or of the property considered (frontier orbitals energy level, absorption, fluorescence, phosphorescence).     

Role of ABCA7 in Human Health and in Alzheimer’s Disease

Several studies, including genome wide association studies (GWAS), have strongly suggested a central role for the ATP-binding cassette transporter subfamily A member 7 (ABCA7) in Alzheimer’s disease (AD). This ABC transporter is now considered as an important genetic determinant for late onset Alzheimer disease (LOAD) by regulating several molecular processes such as cholesterol metabolism and amyloid processing and clearance. In this review we shed light on these new functions and their cross-talk, explaining its implication in brain functioning, and therefore in AD onset and development.     

Global modeling of hydrogen using GFDL-AM4.1: Sensitivity of soil removal and radiative forcing

Hydrogen (H₂) has been proposed as an alternative energy carrier to reduce the carbon footprint and associated radiative forcing of the current energy system. Here, we describe the representation of H₂ in the GFDL-AM4.1 model including updated emission inventories and improved representation of H₂ soil removal, the dominant sink of H₂. The model best captures the overall distribution of surface H₂, including regional contrasts between climate zones, when v_d(H₂) is modulated by soil moisture, temperature, and soil carbon content. We estimate that the soil removal of H₂ increases with warming (2–4% per K), with large uncertainties stemming from different regional response of soil moisture and soil carbon. We estimate that H₂ causes an indirect radiative forcing of 0.84 mW m^?2/(Tg(H₂)yr^?1) or 0.13 mW m^?2 ppbv^?1, primarily due to increasing CH₄ lifetime and stratospheric water vapor production.     

Mastering the structure of PLA foams made with extrusion assisted by supercritical CO2

In this study, the outcome of operating conditions of extrusion assisted by supercritical CO₂ for the manufacture of poly(lactic acid) foams was investigated. It was found that the temperature before and inside the die was the most prominent parameter to tune the foam properties. Foam porosity as high as 96% could be obtained (for die temperature between 109 and 112 °C), representing a total expansion exceeding 30. In this temperature range, low crystallinity (≈6%) was induced giving foams with high radial expansion i.e., large diameters and open porosity. At 112 °C, the CO₂ was able to greatly expand the foams, providing 73% of its potential blowing effect. On the other hand, a low die temperature (below a die temperature of 107 °C) induces a significantly higher level of crystallinity resulting in foams with closed‐porosity and a large longitudinal expansion due to higher strength of the polymer melt. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45067.     

Heuristic and exact algorithms for the multi-pile vehicle routing problem

The multi-pile vehicle routing problem is a particular combination of loading and routing problems, in which items have to be loaded into different piles within vehicles, and then delivered with minimum cost. The problem is motivated by a real-world timber distribution problem, and is of both theoretical and practical interest. In this paper, we first develop heuristic and exact methods to solve the loading problem. We then include these methods into a tailored combination of Variable Neighborhood Search and Branch-and-Cut, to solve the overall problem. Extensive computational results show how the resulting algorithms are capable of solving to optimality a large number of small-size instances, and of consistently outperforming previous algorithms from the literature on large-size and real-world instances.     

Suspended and localized single nanostructure growth across a nanogap by an electric field

Direct growth of a suspended single nanostructure (SSN) at a specific location is presented. The SSN is grown across a metallic nanoscale gap by migration in air at room temperature. The nanogap is fabricated by industrial standard optical lithography and anisotropic wet chemical silicon etching. A DC current bias, 1 nA, is applied across the metallic gap to induce nanoscale migration of Zn or ZnO. The history of the voltage drop across the gap as a function of time clearly indicates the moment when migration begins. The shape of SSNs grown across the nanogap by the migration is asymmetric at each electrode due to the asymmetric electric field distribution within the nanogap. An SSN can be used as the platform for two-terminal active or passive nanoscale electronics in optoelectronics, radio frequency (RF) resonators, and chemical/biological sensors.     

Road network monitoring: algorithms and a case study

Road network monitoring is an activity conducted daily by the Ministry of Transportation of Quebec. The complete network must be monitored every 2 weeks. In this setting, the usual objective in arc routing of minimizing the total travel distance is irrelevant. The vehicles are equipped with global positioning systems (GPS) locating devices to monitor events and trace routes. Since most planned route are not completed because of events on the network, there is a need to continuously re-plan and re-schedule routes. We developed a methodology to achieve this task by gathering data from the GPS trace, matching it to the planned routes within a geographic information systems (GIS) and then use mathematical algorithms to propose a new schedule with new routes. The interurban road network studied consists in a hierarchy of three classes of roads that have different monitoring standards. We tested three different methods using different objectives depending on the operators’ needs. Results show that the method that implies rescheduling based on assignment and reconstruction of routes with an arc-adding method gives the best coverage for each class of road.     

Nail changes in patients infected with human immunodeficiency virus. A prospective controlled study

OBJECTIVES: To study the frequency of nail changes in a population of human immunodeficiency virus (HIV)-infected patients and to evaluate the specificity of these findings by comparison with HIV-negative control subjects. DESIGN: Prospective controlled study. Nail changes were recorded by a standardized clinical examination (curvature, nail plate, color, onychomycosis). In case of clinical diagnosis of onychomycosis, mycological culture was performed. SETTING: Primary care university hospital. PATIENTS: A total of 155 HIV-1-positive patients and 103 healthy HIV-negative control subjects of comparable age and sex ratio. INTERVENTION: None. MAIN OUTCOME MEASURE: Clinical examination findings. RESULTS: Nail symptoms were present in 67.7% of HIV-positive patients vs 34.0% of controls (P < .001). The following symptoms were significantly more frequent in the HIV group: clubbing (5.8%) (P < .05), transverse lines (7.1%) (P < .01), onychoschizia (7.1%) (P < .05), leukonychia (14.3%) (P < .001), and longitudinal melanonychia (14.8%) (P < .01). The main finding was onychomycosis in 30.3% of patients vs 12.6% of controls (P < .001). Trichophyton rubrum was present in 48% of onychomycoses and unusual Candida species were also recorded. Multiple fungi were frequently cultured in a single patient. The mean CD4+ cell count was lower in patients with onychomycosis and the frequency of onychomycosis increased in advanced stages of HIV disease. Acquired total leukonychia of the 20 nails was present in 4% of patients. CONCLUSION: Nail symptoms are much more frequent in patients with HIV than in healthy controls, and some of them could be linked to the level of immunosuppression.     

Cognitive—behavioral treatment of obsessive thoughts: A controlled study.

Twenty-nine patients with obsessive-compulsive disorder as diagnosed in accordance with the Diagnostic and Statistical Manual of Mental Disorders (3rd ed., revised; American Psychiatric Association, 1987) who did not have overt compulsive rituals were randomly assigned to treatment and waiting-list conditions. Patients in the treatment condition received cognitive-behavioral therapy consisting of a detailed explanation of the occurrence and maintenance of obsessive thoughts, exposure to obsessive thoughts, response prevention of all neutralizing strategies, cognitive restructuring, and relapse prevention. Compared with waiting-list patients, treated patients improved significantly on measures of severity of obsessions, current functioning, self-report obsessive-compulsive symptoms, and anxiety. When waiting-list patients were subsequently treated, the combined group improved on all outcome measures. Treatment gains were maintained at 6-month follow-up. Results indicate that cognitive-behavioral therapy is effective in the treatment of patients with obsessive thoughts, a group that has often been considered resistant to treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Digital Footprinting: Uncovering Tourists with User-Generated Content

Novel methods and tools are being developed to explore the significance of the new types of user-related spatiotemporal data. This approach helps uncover the presence and movements of tourists from cell phone network data and the georeferenced photos they generate.