Microfluidics: Continuous‐Flow Synthesis of Nanoparticle Dispersions for the Fabrication of Organic Solar Cells

State-of-the-art solvents for the fabrication of organic solar cells are mostly toxic or hazardous. First attempts to deposit light-harvesting layers from aqueous or alcoholic nanoparticle dispersions instead have been successful on laboratory scale, enabling future eco-friendly production of organic solar cells. In this work, a scalable high-throughput continuous-flow microfluidic system is employed to synthesize surfactant-free organic semiconductor dispersions by nanoprecipitation. By adjusting the differential speed of the syringe pumps, the concentration of the initial solute and the irradiation of the microfluidic chip, the synthesis can be controlled for tailored dispersion concentrations and nanoparticle sizes. The resulting dispersions are highly reproducible, and the semiconductor inks are stable for at least one year. The synthesis of the dispersions is exemplified on a polymer/fullerene combination with large-scale availability

Organic Solar Cells: Electrostatic Stabilization of Organic Semiconductor Nanoparticle Dispersions by Electrical Doping

Organic semiconductor nanoparticle dispersions are electrostatically stabilized with the p-doping agent 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F$_4$TCNQ), omitting the need for surfactants. Smallest amounts of F$_4$TCNQ stabilize poly(3-hexylthiophene) dispersions and reduce the size of the nanoparticles significantly. The concept is then readily transferred to synthesize dispersions from a choice of light-harvesting benzodithiophene-based copolymers. Dispersions from the corresponding polymer:fullerene blends are used to fabricate organic solar cells (OSCs). In contrast to the widely used stabilizing surfactants, small amounts of F$_4$TCNQ show no detrimental effect on the device performance. This concept paves the way for the eco-friendly fabrication of OSCs from nanoparticle dispersions of high-efficiency light-harvesting semiconductors by eliminating environmentally hazardous solvents from the deposition process

Iodine‐Stabilized Organic Nanoparticle Dispersions for the Fabrication of 10% Efficient Non‐Fullerene Solar Cells

High-performance organic solar cells are deposited from eco-friendly semiconductor dispersions by applying reversible electrostatic stabilization while omitting the need for stabilizing surfactants. The addition of iodine fosters the oxidation (p-doping) of the light-harvesting polymer, effectively promoting the electrostatic repulsion of the nanoparticles and hence the colloidal stability of the respective dispersions. The oxidation of polymers with iodine is reversible: after thin-film deposition and after thermal evaporation of the iodine, the corresponding polymer:non-fullerene solar cells yield power conversion efficiencies of up to 10.6%

Xenon and Sevoflurane Provide Analgesia during Labor and Fetal Brain Protection in a Perinatal Rat Model of Hypoxia-Ischemia

It is not possible to identify all pregnancies at risk of neonatal hypoxic-ischemic encephalopathy (HIE). Many women use some form of analgesia during childbirth and some anesthetic agents have been shown to be neuroprotective when used as analgesics at subanesthetic concentrations. In this study we sought to understand the effects of two anesthetic agents with presumptive analgesic activity and known preconditioning-neuroprotective properties (sevoflurane or xenon), in reducing hypoxia-induced brain damage in a model of intrauterine perinatal asphyxia. The analgesic and neuroprotective effects at subanesthetic levels of sevoflurane (0.35%) or xenon (35%) were tested in a rat model of intrauterine perinatal asphyxia. Analgesic effects were measured by assessing maternal behavior and spinal cord dorsal horn neuronal activation using c-Fos. In separate experiments, intrauterine fetal asphyxia was induced four hours after gas exposure; on post-insult day 3 apoptotic cell death was measured by caspase-3 immunostaining in hippocampal neurons and correlated with the number of viable neurons on postnatal day (PND) 7. A separate cohort of pups was nurtured by a surrogate mother for 50 days when cognitive testing with Morris water maze was performed. Both anesthetic agents provided analgesia as reflected by a reduction in the number of stretching movements and decreased c-Fos expression in the dorsal horn of the spinal cord. Both agents also reduced the number of caspase-3 positive (apoptotic) neurons and increased cell viability in the hippocampus at PND7. These acute histological changes were mirrored by improved cognitive function measured remotely after birth on PND 50 compared to control group. Subanesthetic doses of sevoflurane or xenon provided both analgesia and neuroprotection in this model of intrauterine perinatal asphyxia. These data suggest that anesthetic agents with neuroprotective properties may be effective in preventing HIE and should be tested in clinical trials in the future

Indústria e universidade: a cooperação internacional e institucional e o protagonismo da mobilidade estudantil nos sistemas de inovação da Alemanha

Resumo O presente trabalho visa apresentar um quadro sobre as políticas empreendidas pela República Federal da Alemanha no sentido de captar as potencialidades técnico-científicas ao redor do mundo, por meio da atração de estudantes e pesquisadores para as universidades do país, levando em consideração as motivações que originaram tal necessidade para a manutenção de sua competitividade industrial, trespassando percalços e desafios econômicos e sociais percebidos e inserindo tal processo no campo da cooperação internacional. Para tanto, o artigo procurará promover a discussão sobre o papel da universidade no processo de produção de conhecimento e, em seguida, ressaltando a cooperação internacional e interinstitucional como elemento fundamental para a mobilidade estudantil e a produção e troca de conhecimento, buscará situar o processo de migração na Alemanha. A partir disso, estabelecendo relações entre produção de conhecimento e geração de inovação, procurará avaliar como essa realidade se manifesta na competitividade industrial alemã. Assim, além de pesquisa bibliográfica sobre o tema, o artigo estará amparado pelo levantamento dos dados disponíveis que demonstram não só a necessidade da iniciativa, mas como ela vem alterando a disposição e a articulação entre os setores com tal finalidade, buscando avaliar os resultados até então observados. Nesse sentido, serão analisados: a circulação de estudantes do mundo em relação à Alemanha; a participação das áreas privadas, estatais e universitárias em pesquisa e inovação; e os resultados apresentados. O período de 2000 a 2012 foi dividido para que se possa delinear a realidade enfrentada pelo país, resultando na implementação do programa. Ainda com base nas informações disponíveis, o artigo procurará delimitar o programa de inovação alemão de maneira a concluir com a indicação de um eventual modelo de geração de inovação passível de reprodução por países em desvantagem em termos de desenvolvimento frente à Alemanha

Report from Working Group 3: Beyond the standard model physics at the HL-LHC and HE-LHC

This is the third out of five chapters of the final report [1] of the Workshop on Physics at HL-LHC, and perspectives on HE-LHC [2]. It is devoted to the study of the potential, in the search for Beyond the Standard Model (BSM) physics, of the High Luminosity (HL) phase of the LHC, defined as $3$ ab$^{-1}$ of data taken at a centre-of-mass energy of 14 TeV, and of a possible future upgrade, the High Energy (HE) LHC, defined as $15$ ab$^{-1}$ of data at a centre-of-mass energy of 27 TeV. We consider a large variety of new physics models, both in a simplified model fashion and in a more model-dependent one. A long list of contributions from the theory and experimental (ATLAS, CMS, LHCb) communities have been collected and merged together to give a complete, wide, and consistent view of future prospects for BSM physics at the considered colliders. On top of the usual standard candles, such as supersymmetric simplified models and resonances, considered for the evaluation of future collider potentials, this report contains results on dark matter and dark sectors, long lived particles, leptoquarks, sterile neutrinos, axion-like particles, heavy scalars, vector-like quarks, and more. Particular attention is placed, especially in the study of the HL-LHC prospects, to the detector upgrades, the assessment of the future systematic uncertainties, and new experimental techniques. The general conclusion is that the HL-LHC, on top of allowing to extend the present LHC mass and coupling reach by $20-50\%$ on most new physics scenarios, will also be able to constrain, and potentially discover, new physics that is presently unconstrained. Moreover, compared to the HL-LHC, the reach in most observables will, generally more than double at the HE-LHC, which may represent a good candidate future facility for a final test of TeV-scale new physics

Differential cross section measurements for the production of a W boson in association with jets in proton–proton collisions at √s = 7 TeV

Measurements are reported of differential cross sections for the production of a W boson, which decays into a muon and a neutrino, in association with jets, as a function of several variables, including the transverse momenta (pT) and pseudorapidities of the four leading jets, the scalar sum of jet transverse momenta (HT), and the difference in azimuthal angle between the directions of each jet and the muon. The data sample of pp collisions at a centre-of-mass energy of 7 TeV was collected with the CMS detector at the LHC and corresponds to an integrated luminosity of 5.0 fb[superscript −1]. The measured cross sections are compared to predictions from Monte Carlo generators, MadGraph + pythia and sherpa, and to next-to-leading-order calculations from BlackHat + sherpa. The differential cross sections are found to be in agreement with the predictions, apart from the pT distributions of the leading jets at high pT values, the distributions of the HT at high-HT and low jet multiplicity, and the distribution of the difference in azimuthal angle between the leading jet and the muon at low values.United States. Dept. of EnergyNational Science Foundation (U.S.)Alfred P. Sloan Foundatio

Impacts of the Tropical Pacific/Indian Oceans on the Seasonal Cycle of the West African Monsoon

The current consensus is that drought has developed in the Sahel during the second half of the twentieth century as a result of remote effects of oceanic anomalies amplified by local land–atmosphere interactions. This paper focuses on the impacts of oceanic anomalies upon West African climate and specifically aims to identify those from SST anomalies in the Pacific/Indian Oceans during spring and summer seasons, when they were significant. Idealized sensitivity experiments are performed with four atmospheric general circulation models (AGCMs). The prescribed SST patterns used in the AGCMs are based on the leading mode of covariability between SST anomalies over the Pacific/Indian Oceans and summer rainfall over West Africa. The results show that such oceanic anomalies in the Pacific/Indian Ocean lead to a northward shift of an anomalous dry belt from the Gulf of Guinea to the Sahel as the season advances. In the Sahel, the magnitude of rainfall anomalies is comparable to that obtained by other authors using SST anomalies confined to the proximity of the Atlantic Ocean. The mechanism connecting the Pacific/Indian SST anomalies with West African rainfall has a strong seasonal cycle. In spring (May and June), anomalous subsidence develops over both the Maritime Continent and the equatorial Atlantic in response to the enhanced equatorial heating. Precipitation increases over continental West Africa in association with stronger zonal convergence of moisture. In addition, precipitation decreases over the Gulf of Guinea. During the monsoon peak (July and August), the SST anomalies move westward over the equatorial Pacific and the two regions where subsidence occurred earlier in the seasons merge over West Africa. The monsoon weakens and rainfall decreases over the Sahel, especially in August.Peer reviewe