Abstract
Vitamin B
12
plays a crucial role in enzymatic transformations. This natural compound proved also useful as a catalyst in numerous organic reactions. Commercial availability and lower cost ...than precious metal complexes, make cobalamin an attractive candidate for a broader use as a benign Co-catalyst. Herein, the vitamin B
12
-catalyzed dicarbofuntionalization of bromoalkenes with electrophilic olefins is reported leading to substituted pyrrolidines and piperidines in decent yields after only 15 minutes under light irradiation.
Abstract
Considering the current challenges of the A
3
redox-neutral C1-alkynylation of tetrahydroisoquinolines (THIQs), we studied this synthetic tool under visible light photocatalysis and ...transition-metal catalysis in order to describe alternative reaction conditions and discuss possible improvements to this process. We demonstrated that 1-alkynylated THIQs can be readily obtained by three different approaches: iridium-based photocatalysis and copper (CuBr(PPh
3
)
3
) and silver (AgNO
3
) catalysis under mild, selective and accessible reaction conditions. Among these approaches, the copper(I)-based methodology resulted in the most robust, optimal reaction conditions for the synthesis of a series of 18 1-alkynylated THIQs in moderate to excellent yields and with high selectivity for the
endo
-alkynylated products. Moreover, this reaction can be accelerated by microwave irradiation (120 °C, 15 min) affording a novel library of diverse THIQs with alkyne and
N
-substituent moieties, from unreactive and uncommon substrates, that could be further transformed into new compounds of interest.
The Zwicky Transient Facility Dekany, Richard; Smith, Roger M.; Riddle, Reed ...
Publications of the Astronomical Society of the Pacific,
03/2020, Volume:
132, Issue:
1009
Journal Article
Peer reviewed
The Zwicky Transient Facility (ZTF) Observing System (OS) is the data collector for the ZTF project to study astrophysical phenomena in the time domain. ZTF OS is based upon the 48 inch aperture ...Schmidt-type design Samuel Oschin Telescope at the Palomar Observatory in Southern California. It incorporates new telescope aspheric corrector optics, dome and telescope drives, a large-format exposure shutter, a flat-field illumination system, a robotic bandpass filter exchanger, and the key element: a new 47-square-degree, 600 megapixel cryogenic CCD mosaic science camera, along with supporting equipment. The OS collects and delivers digitized survey data to the ZTF Data System (DS). Here, we describe the ZTF OS design, optical implementation, delivered image quality, detector performance, and robotic survey efficiency.
Abstract
This paper aims to determine the levels of exposure to neutron and photon radiation among the personnel engaged in cyclotron operation and the personnel engaged in the production of ...radiopharmaceuticals, with the use of the environmental radiation monitoring system (RMS) installed in the positron emission tomography laboratory. The annual exposures of employees operating the cyclotron measured with the use of the RMS system are: 1.39 ± 0.16 mSv in case of photon radiation and 2.61 ± 0.14 mSv in case of neutron radiation. In the case of employees in the radiopharmaceuticals’ production zone, the annual exposures measured by means of the RMS system are 0.15 ± 0.03 mSv in case of photon radiation and 0.11 ± 0.01 mSv in case of neutron radiation. The exposure levels among the personnel engaged in cyclotron operation and the personnel engaged in the production of radiopharmaceuticals are below the permissible radiation dose limits.
Abstract
The eye lens exposure among 16 technicians in two nuclear medicine departments at university hospitals in Finland was investigated by measuring the operational quantity Hp(3) using EYE-D ...dosemeters. For all workers, the annual mean Hp(3) was estimated to be 1.1 mSv (max. 3.9 mSv). The relation between Hp(3) to routinely monitored personal dose equivalent Hp(10) was clearly correlated. Considering individual dose measurement periods (2–4 weeks), the Hp(3)/Hp(10) ratio was 0.7 (Pearson’s coefficient r = 0.90, p < 0.001, variation of ratio 0.1–2.3). The variation decreased considerably with increasing Hp(10) (σ2 = 0.04 vs. 0.43 for Hp(10) > 0.1 mSv vs. < 0.1 mSv, respectively), i.e. higher Hp(10) predicts Hp(3) more reliably. Moreover, annual Hp(10) data from national dose register during 2009–2018 were used to derive the annual Hp(3) applying the Hp(3)/Hp(10) ratio. The data from Finnish nuclear medicine departments imply that routine measurements of Hp(3) among nuclear medicine technicians are not justified.
In this paper, in connection with the program of extending the Curry–Howard isomorphism to classical logic, we study the
$\lambda \mu$
-calculus of Parigot emphasizing the difference between the ...original version of Parigot and the version of de Groote in terms of normalization properties. In order to talk about a satisfactory representation of the integers, besides the usual
$\beta$
-,
$\mu$
-, and
$\mu '$
-reductions, we consider the
$\lambda \mu$
-calculus augmented with the reduction rules
$\rho$
,
$\theta$
and
$\varepsilon$
. We show that we need all of these rules for this purpose. Then we prove that, with the syntax of Parigot, the calculus enjoys the strong normalization property even when we add the rules
$\rho$
,
$\theta$
, and
$\epsilon$
, while the
$\lambda \mu$
-calculus presented with the more flexible de Groote-style syntax, in contrast, has only the weak normalization property. In particular, we present a normalization algorithm for the
$\beta \mu \mu '\rho \theta \varepsilon$
-reduction in the de Groote-style calculus.
Abstract
Background
Fine particulate matter (PM2.5) is a ubiquitous air pollutant, and it has been reported to be closely associated with lung inflammatory injury. In this study, the potential ...molecular mechanisms underlying PM2.5-induced cellular inflammation in human bronchial epithelial (BEAS-2B) cells were investigated.
Materials and methods
Ambient PM2.5 particulates from Suzhou, China, were collected and re-suspended in ultrapure water. Cellular damages, characterized by oxidative stress, mitochondrial injury, and inflammatory cytokine production, were determined in 24 h PM2.5-treated BEAS-2B cells with or without 3-methyladenine (3-MA; autophagy inhibitor) pretreatment. Biomarkers related to oxidative damage, inflammatory injury and autophagy signaling pathways were also measured.
Results
Uptake of PM2.5 in BEAS-2B cells induced cellular oxidative damage, mitochondrial injury, and inflammatory responses as indicated by a significant decrease in GSH/GSSG ratio, increased MDA content, dilated mitochondria with loss and rupture of crista, and production of inflammatory cytokines. Activation of Nrf-2/TXNIP-mediated NF-κB and Bnip3L/NIX-dependent mitophagy signaling pathways, as well as accumulation of autophagosomes and autolysosomes, were also observed. A 6 h pretreatment of 3-MA increased PM2.5-induced oxidative damage and cellular inflammation as indicated by increasing protein levels of HO-1, TXNIP, Bnip3L/NIX and IL-8 gene expression.
Conclusions
PM2.5 induced cellular inflammatory injury by oxidative stress, mitochondrial dysfunction, and mitophagy initiation. Although induction of Bnip3L/NIX-mediated mitophagy in BEAS-2B cells appeared to confer protection in response to PM2.5, dysfunction of autophagic flux may be a critical contributor to defective mitophagy and cellular inflammatory response.
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