Synthesis of Chiral Cyclopentenones Simeonov, Svilen P; Nunes, João P M; Guerra, Krassimira ...
Chemical reviews,
05/2016, Letnik:
116, Številka:
10
Journal Article
Recenzirano
The cyclopentenone unit is a very powerful synthon for the synthesis of a variety of bioactive target molecules. This is due to the broad diversity of chemical modifications available for the enone ...structural motif. In particular, chiral cyclopentenones are important precursors in the asymmetric synthesis of target chiral molecules. This Review provides an overview of reported methods for enantioselective and asymmetric syntheses of cyclopentenones, including chemical and enzymatic resolution, asymmetric synthesis via Pauson-Khand reaction, Nazarov cyclization and organocatalyzed reactions, asymmetric functionalization of the existing cyclopentenone unit, and functionalization of chiral building blocks.
We present new deep ALMA and Hubble Space Telescope (HST)/WFC3 observations of MASOSA and VR7, two luminous Ly emitters (LAEs) at z = 6.5, for which the UV continuum levels differ by a factor of ...four. No IR dust continuum emission is detected in either, indicating little amounts of obscured star formation and/or high dust temperatures. MASOSA, with a UV luminosity M1500 = −20.9, compact size, and very high Ly , is undetected in C ii to a limit of LC ii < 2.2 × 107 L , implying a metallicity Z 0.07 Z . Intriguingly, our HST data indicate a red UV slope β = −1.1 0.7, at odds with the low dust content. VR7, which is a bright (M1500 = −22.4) galaxy with moderate color (β = −1.4 0.3) and Ly EW0 = 34 , is clearly detected in C ii emission (S/N = 15). VR7's rest-frame UV morphology can be described by two components separated by 1.5 kpc and is globally more compact than the C ii emission. The global C ii/UV ratio indicates Z 0.2 Z , but there are large variations in the UV/C ii ratio on kiloparsec scales. We also identify diffuse, possibly outflowing, C ii-emitting gas at 100 km s−1 with respect to the peak. VR7 appears to be assembling its components at a slightly more evolved stage than other luminous LAEs, with outflows already shaping its direct environment at z ∼ 7. Our results further indicate that the global C ii−UV relation steepens at SFR < 30 M yr−1, naturally explaining why the C ii/UV ratio is anticorrelated with Ly EW in many, but not all, observed LAEs.
Nowadays, concerns about climate change have contributed significantly to changing the paradigm in the urban transportation sector towards vehicle electrification, where purely electric or hybrid ...vehicles are increasingly a new reality, supported by all major automotive brands. Nevertheless, new challenges are imposed on the current electrical power grids in terms of a synergistic, progressive, dynamic and stable integration of electric mobility. Besides the traditional unidirectional charging, more and more, the adoption of a bidirectional interconnection is expected to be a reality. In addition, whenever the vehicle is plugged-in, the on-board power electronics can also be used for other purposes, such as in the event of a power failure, regardless if the vehicle is in charging mode or not. Other new opportunities, from the electrical grid point of view, are even more relevant in the context of off-board power electronics systems, which can be enhanced with new features as, for example, compensation of power quality problems or interface with renewable energy sources. In this sense, this paper aims to present, in a comprehensive way, the new challenges and opportunities that smart grids are facing, including the new technologies in the vehicle electrification, towards a sustainable future. A theoretical analysis is also presented and supported by experimental validation based on developed laboratory prototypes.
Objective
Evaluation of relevance and feasibility of universal newborn congenital cytomegalovirus infection (cCMVI) screening in saliva.
Design
Retrospective, population‐based cohort study.
Setting
...Clamart, France, 2016–2020.
Population
All neonates born consecutively in our level III maternity unit.
Methods
CMV PCR in saliva for all neonates at birth, and, if positive, CMV PCR in urine to confirm or exclude cCMVI. Prospective and retrospective characterisation of maternal infections. ROC curve analysis to assess saliva PCR performances. Acceptability of screening among staff members evaluated by a survey.
Main outcome measures
Number of cCMVI neonates; number of expected and unexpected cCMVI.
Results
Among 15 341 tested neonates, 63 had cCMVI (birth prevalence of 0.4%, 95% CI 0.3–0.5). In 50% of cases, maternal infection was a non‐primary infection (NPI) during pregnancy. cCMVI was expected or suspected (maternal primary infection PI, antenatal or neonatal signs) in 24/63 neonates (38%), and unexpected in 39/63 neonates (62%). The best CMV saliva threshold to predict cCMVI was 356 (2.55 log) copies/ml 95% CI 2.52 log–3.18 log, with an area under the ROC curve of 0.97. Over 90% of the 72 surveyed staff members reported that the screening was easy and quick. No parent refused the screening.
Conclusions
Universal screening for cCMVI with CMV PCR on saliva samples is feasible and highly acceptable to parents and healthcare providers. Over half (62%) of the cases had no prenatal/neonatal signs of cCMVI or a maternal history of CMV infection during pregnancy and would probably not have been diagnosed without universal screening.
Tweetable
In 62% of congenital cytomegalovirus infection cases, only universal neonatal screening in saliva can detect infection.
Tweetable
In 62% of congenital cytomegalovirus infection cases, only universal neonatal screening in saliva can detect infection.
The increasing interest on the application of ionic liquids (ILs) to a wide range of processes and products has been hampered by a lack of toxicological data, mainly in what concerns novel cations, ...such as guanidinium, phosphonium, and functionalized and non-functionalized imidazolium-based ILs. The present study reports the toxicity of five guanidinium-, six phosphonium, and six imidazolium-based ILs, towards the luminescent marine bacteria
Vibrio fischeri. These new results clearly show that guanidinium-, unlike the imidazolium- and phosphonium-based ILs, do not follow the trend of increasing toxicity with the increase in the alkyl chain length. Moreover, the introduction of oxygenated groups on the alkyl chains, such as ether and ester, leads to a decrease of the toxicity of guanidinium and also imidazolium compounds. In what respects the effect of the different cations, it is possible to recognize that the phosphonium-based ILs seem to be more toxic when compared to the analog imidazolium-based ILs (with the same anion and alkyl chains).
► Toxicological profile of ILs towards
Vibrio fischeri. ► Various ILs families guanidinium, phosphonium, and imidazolium tested. ► Two different established trends: “side chain effect” and “cut-off” effect. ► Decrease in toxicity with the oxygenation of the side chains. ► Affect of anion related with the elongation of the alkyl chains conjugated.
Recent research advances in sensors, wireless communications, network protocols, microelectronics, cloud computing, and machine learning, among others, are driving the growth of the Internet of ...Things (IoT) ...
Abstract
We assemble a large comprehensive sample of 2534
z
∼ 2, 3, 4, 5, 6, 7, 8, and 9 galaxies lensed by the six clusters from the Hubble Frontier Fields (HFF) program. Making use of the ...availability of multiple independent magnification models for each of the HFF clusters and alternatively treating one of the models as the “truth,” we show that the median magnification factors from the v4 parametric models are typically reliable to values of 30–50, and in one case to 100. Using the median magnification factor from the latest v4 models, we estimate the UV luminosities of the 2534 lensed
z
∼ 2–9 galaxies, finding sources as faint as −12.4 mag at
z
∼ 3 and −12.9 mag at
z
∼ 7. We explicitly demonstrate the power of the surface density–magnification relations Σ(
z
) versus
μ
in the HFF clusters to constrain both distant galaxy properties and cluster lensing properties. Based on the Σ(
z
) versus
μ
relations, we show that the median magnification estimates from existing public models must be reliable predictors of the true magnification
μ
to
μ
< 15 (95% confidence). We also use the observed Σ(
z
) versus
μ
relations to derive constraints on the evolution of the luminosity function faint-end slope from
z
∼ 7 to
z
∼ 2, showing that faint-end slope results can be consistent with blank-field studies if, and only if, the selection efficiency shows no strong dependence on the magnification factor
μ
. This can only be the case if very low-luminosity galaxies are very small, being unresolved in deep lensing probes.
The decentralization in the electrical power grids has gained increasing importance, especially in the last two decades, since transmission system operators (TSO), distribution system operators (DSO) ...and consumers are more aware of energy efficiency and energy sustainability issues. Therefore, globally, due to the introduction of energy production technologies near the consumers, in residential and industrial sectors, new scenarios of distributed energy resources (DER) are emerging. In order to guarantee an adequate power management in the electrical power grids, incorporating producers, consumers and producers-consumers (prosumers) together, it is important to adopt intelligent systems and platforms that allow the provision of information on energy consumption and production in real time, as well as for obtaining a fair price for the sale and purchase of energy. In this paper, we analyze the literature to identify the appropriate solutions to implement a decentralized electrical power grid based on sensors, blockchain and smart contracts, evaluating the current state of the art and pilot projects already in place. We also discuss a proposal for a power grid model, with renewable energy production, combining Internet of Things, blockchain and smart contracts.
![Resolved UV and [C ii] Stru...](http://api.summon.serialssolutions.com/2.0.0/image/issn/XR4PS5YY4K/0004-637X/small "Resolved UV and [C ii] Structures of Luminous Galaxies within the Epoch of Reionization")
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