A novel electrochemical approach to access alkyl alkenesulfonates via a multicomponent reaction was developed. The metal‐free method features easy‐to‐use SO2 stock solution forming monoalkylsulfites ...from alcohols with an auxiliary base in‐situ. These intermediates serve a dual role as starting materials and as supporting electrolyte enabling conductivity. Anodic oxidation of the substrate styrene, radical addition of these monoalkylsulfites and consecutive second oxidation and deprotonation preserve the double bond and form alkyl β‐styrenesulfonates in a highly regio‐ and stereoselective fashion. The feasibility of this electrosynthetic method is demonstrated in 44 examples with yields up to 81 %, employing various styrenes and related substrates as well as a diverse set of alcohols. A gram‐scale experiment underlines the applicability of this process, which uses inexpensive and readily available electrode materials.
A first of its kind electrochemical approach for the direct synthesis of alkyl alkenesulfonates using styrenes, SO2 stock solution and alcohols was developed. The reaction features the in‐situ generation of a monoalkylsulfite species with subsequent radical addition to an anodically oxidized styrene substrate. The applicability of the protocol was demonstrated with a broad scope as well as a gram‐scale reaction.
Sulfonyl fluorides are valuable synthetic motifs for a variety of applications, among which sulfur(VI) fluoride exchange-based “click chemistry” is currently the most prominent. Consequently, the ...development of novel and efficient synthetic methods to access these functional groups is of great interest. Herein, we report a mild and environmentally benign electrochemical approach to prepare sulfonyl fluorides using thiols or disulfides, as widely available starting materials, in combination with KF, as an inexpensive, abundant and safe fluoride source. No additional oxidants nor additional catalysts are required and, due to mild reaction conditions, the reaction displays a broad substrate scope, including a variety of alkyl, benzyl, aryl and heteroaryl thiols or disulfides.
This paper focuses on the understanding of the Random Telegraph Signal (RTS) in Single-Photon Avalanche Diodes (SPAD). We studied the RTS of two different SPAD layouts, designed and implemented in a ...150-nm CMOS process, after proton irradiation. The two structures are characterized by different junction types: the first structure is constituted by a P+/Nwell junction, while the second is formed by a Pwell/Niso junction. RTS occurrence has been measured in about one thousand SPAD pixels and the differences addressed in two layouts are motivated and discussed. Hypotheses on the RTS origin are drawn by analyzing the RTS time constants and the RTS occurrence evolution as a function of the annealing temperature.
First measurements of beam backgrounds at SuperKEKB Lewis, P.M.; Jaegle, I.; Nakayama, H. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2019, Letnik:
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The high design luminosity of the SuperKEKB electron–positron collider is expected to result in challenging levels of beam-induced backgrounds in the interaction region. Properly simulating and ...mitigating these backgrounds is critical to the success of the Belle II experiment. We report on measurements performed with a suite of dedicated beam background detectors, collectively known as BEAST II, during the so-called Phase 1 commissioning run of SuperKEKB in 2016, which involved operation of both the high energy ring (HER) of 7 GeV electrons as well as the low energy ring (LER) of 4 GeV positrons. We describe the BEAST II detector systems, the simulation of beam backgrounds, and the measurements performed. The measurements include standard ones of dose rates versus accelerator conditions, and more novel investigations, such as bunch-by-bunch measurements of injection backgrounds and measurements sensitive to the energy spectrum and angular distribution of fast neutrons. We observe beam–gas, Touschek, beam–dust, and injection backgrounds. As there is no final focus of the beams in Phase 1, we do not observe significant synchrotron radiation, as expected. Measured LER beam–gas backgrounds and Touschek backgrounds in both rings are slightly elevated, on average three times larger than the levels predicted by simulation. HER beam–gas backgrounds are on average two orders of magnitude larger than predicted. Systematic uncertainties and channel-to-channel variations are large, so that these excesses constitute only 1–2 sigma level effects. Neutron background rates are higher than predicted and should be studied further. We will measure the remaining beam background processes, due to colliding beams, in the imminent commissioning Phase 2. These backgrounds are expected to be the most critical for Belle II, to the point of necessitating replacement of detector components during the Phase 3 (full-luminosity) operation of SuperKEB.
The Level-1 barrel trigger of the ATLAS experiment is based on the resistive plate chambers (RPCs) detectors. The on-detector trigger electronics identifies muons with specific values of transverse ...momentum, by using coincidences between different layers of detectors. Trigger data are then transferred from on-detector to off-detector trigger electronics boards. Data are processed by a complex system, which combines trigger data from the barrel and the end-cap regions and provide the combined muon candidate to the central trigger processor (CTP). The system has been performing well for almost a decade. However, in order to cope with continuously increasing large hadron collider luminosity and more demanding requirements on trigger efficiency and performance, various upgrades for the full-trigger system were already deployed and others are foreseen in the next years. Most of the trigger upgrades are based on the state-of-the-art technologies and allow designing more complex trigger menus, increasing processing power and data transfer bandwidth in order to send more trigger candidates, to perform topological selections, and to support new physics studies. In this paper, we describe the design of the first prototype of the barrel interface board, designed around a Xilinx field-programmable gate array, which transfers RPC trigger data to the CTP system; the board supports the optical transmission of trigger data with fixed latency and new trigger algorithms. We discuss the design strategies, the hardware implementation, and the results of the first functional and integration tests.
BACKGROUNDPoor olfaction is common in older adults and may have profound adverse implications on their health. However, little is known about the potential environmental contributors to poor ...olfaction. OBJECTIVEWe investigated ambient fine particulate matter PM ≤2.5μm in aerodynamic diameter (PM2.5) and nitrogen dioxide (NO2) in relation to poor olfaction in middle-aged to older women. METHODSThe Sister Study is a nationwide cohort of 50,884 women in the United States with annual average air pollutant exposures estimated based on participants' residences from enrollment (2003-2009) through 2017. This analysis was limited to 3,345 women, 50-79 years of age as of January 2018, who completed the Brief Smell Identification Test (B-SIT) in 2018-2019. Poor olfaction was defined as a B-SIT score of ≤9 in the primary analysis. We conducted multivariable logistic regressions, accounting for covariates and study sampling design. RESULTSOverall, we found little evidence for associations of air pollutants with poor olfaction. The odds ratio (OR) and 95% confidence interval (CI) of poor olfaction for each interquartile range (IQR) increment of air pollutants in 2006 were 1.03 (95% CI: 0.91, 1.17) for PM2.5 (per 3.3 μg/m3) and 1.08 (95% CI: 0.96, 1.22) for NO2 (per 5.7 ppb). Results were similar in the analyses using the most recent (2017) or the cumulative average (2006-2017) air pollutant exposure data. Secondary analyses suggested potential association in certain subgroups. The OR per IQR was 1.35 (95% CI: 1.11, 1.65) for PM2.5 among younger participants (<54.2 years of age) and 1.87 (95% CI: 1.29, 2.71) for NO2 among current smokers. DISCUSSIONThis study did not find convincing evidence that air pollutants have lasting detrimental effects on the sense of smell of women 50-79 years of age. The subgroup analyses are exploratory, and the findings need independent confirmation. https://doi.org/10.1289/EHP12066.
In this work, we investigate the influence of three novel 14-aril-14H-dibenzoa,jxanthene derivatives (XDs) modified with different functional groups as very promising hole-transporting materials ...for organic optoelectronic devices. Optical, electronic, and structural properties were analyzed by UV–vis absorption spectrum, cyclic voltammetry, and powder X-ray powder diffraction (XRPD). We investigated the influence of these XD as hole-transporting layers (HTL) on the performance of a simple stack bilayer OLED built with commercial aluminum tris(8-hydroxyquinoline) Alq3 acting as an electron-transporting and emissive layer (EML). As a proof-of-principle the XD devices were compared to reference devices fabricated with one of the most common hole-transporting materials, the N,N′-bis(naphthalen-1-yl)-N,N′-bis(phenyl)-2,2′-dimethylbenzidine (α-NPD). The structure of the devices was ITO/HTL (50 nm)/Alq3 (50 nm)/Al (120 nm) without encapsulation. Under the same conditions, the devices using XD as HTL exhibited high performance and significant durability when compared to the reference ones. These results are also supported by a theoretical study using density functional theory (DFT) showing that this set of XD presents a higher hole mobility than α-NPD. Thus, we demonstrated that this class of molecules are very promising when used as hole-transport material in organic electronic devices.
We showed reduced motor intracortical inhibition (ICI) and paradoxical increase
of intracortical facilitation (ICF) to 1 Hz repetitive transcranial
magnetic stimulation (rTMS) in patients affected by ...migraine with aura (MA). In
conditions of enhanced excitability due to a reduced inhibition, high-frequency
rTMS was found to potentiate intracortical inhibition. Here we explored the
conditioning effects of high-frequency priming stimulation of motor cortex with
the aim of normalizing excitability reverting paradoxical facilitation by
1 Hz rTMS in MA. Nine patients with MA and nine healthy controls
underwent a paired-pulse TMS paradigm to evaluate motor intracortical
excitability (ICI and ICF) before and after the following rTMS conditions:
1 Hz alone or preceded by a real or sham conditioning high-frequency
(10 Hz) rTMS. Sham was used to control for rTMS specificity. In
baseline, ICI was significantly lower in migraineurs with respect to controls.
One hertz stimulation reduced motor evoked potential amplitude and ICF in
healthy controls, while it caused a significant paradoxical ICF increase in
migraineurs. High-frequency rTMS conditioning normalized excitability in
migraine, increasing short ICI and so reversing the paradoxical effects of
1 Hz rTMS. These findings raise the possibility that the interictal
reduced intracortical inhibition in migraine could be normalized by
high-frequency rTMS. This would open perspectives for new treatment strategies
in migraine prevention.
The Belle II experiment will operate at the SuperKEKB e+ e- collider, designed to reach a top luminosity of 8 × 10 35 at the Υ(4s) resonance. The high background environment of the accelerator po ses ...serious challenges to the design of the detector. In particular, the Belle II collaboration is developing an ambitious upgrade program that involves the forward electromagnetic calorimeter. We will use pure CsI crystals, since they have less scintillation time but unfortunately much lower light yield. The electromagnetic calorimeter upgrade is subject to the same detector constraints as the first design; an intense research and development program on photon-detectors and front-end electronics has been initiated by the Italian collaboration. Our preliminary results show that a readout chain using avalanche photodiodes (APDs) to match the detector constraints and a dedicated front-end card for the readout meet the Belle II collaboration requirements. In this paper, we will show the experimental setup and detail the main characteristics of the read-out and power distribution system since the front-end card hosts both a low noise preamplifier and a power regulator to set the single APD bias voltage. The main HV module has been developed for this purpose to deliver a low noise power distribution to the front-end cards. All the relevant parameters of the front-end system can be set and monitored via Ethernet using the Experimental Physics and Industrial Control System. Slow control and monitoring functions in Belle II are performed by a dedicated hardware. The platform has been designed as an uP-based service-oriented platform, capable to offer an integrated solution for all the needs of data acquisition, analysis, and network functions.
Digitally-controlled delay lines (DCDLs) play a key role in timing distribution for trigger and data acquisition systems (TDAQ) of high energy Physics (HEP), where it is often necessary to add an ...open-loop fine-grained programmable phase delay to distributed clocks and/or data lines. In this work, we present the performance of DCDLs implemented according to an all-digital novel architecture. The architecture is completely technology-independent, it is described by means of a hardware description language and it can be placed and routed with automatic tools. Our solution is aimed at being used as a synthesizable block in FPGAs, as a proof-of-concept we implemented a prototype in a Xilinx Kintex-7 FPGA. We discuss the measured performance of the implemented delay line in terms of delay range, resolution and linearity. The logic utilization of the delay lines is also presented in the view of a scalable implementation.
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