Reported herein is the development of the first enantioselective monodentate ligand assisted Pd‐catalyzed domino Heck carbonylation reaction with CO. The highly enantioselective domino Heck ...carbonylation of N‐aryl acrylamides and various nucleophiles, including arylboronic acids, anilines, and alcohols, in the presence of CO was achieved. A novel monodentate phosphoramidite ligand, Xida‐Phos, has been developed for this reaction and it displays excellent reactivity and enantioselectivity. The reaction employs readily available starting materials, tolerates a wide range of functional groups, and provides straightforward access to a diverse array of enantioenriched oxindoles having β‐carbonyl‐substituted all‐carbon quaternary stereocenters, thus providing a facile and complementary method for the asymmetric synthesis of bioactive hexahydropyrroloindole and its dimeric alkaloids.
Domino reaction: A new monodentate phosphoramidite ligand, Xida‐Phos, was used in the enantioselective Pd‐catalyzed domino Heck carbonylative reaction for the synthesis of oxindoles having β‐carbonyl‐substituted all‐carbon quaternary centers. The reaction was used in the asymmetric synthesis of bioactive hexahydropyrroloindole (HPI) and its dimeric alkaloids.
In this work we study the possible QCD exotic states in the doubly charmed baryon sector. Within chiral effective theory, it is predicted that several excited baryons result from the S-wave ...scattering of ground-state doubly charmed baryons (Ξcc++,Ξcc+,Ωcc+) and light pseudoscalar mesons (π, K, η). The excited doubly charmed baryons can be classified by the strangeness (S) and isospin (I) quantum numbers. Two of the excited states are clearly exotic, in the sense that they cannot be explained by the conventional baryons with three quarks, since their quantum numbers are (S,I)=(1,0) and (−1,1). Similar to the charmed scalar meson Ds0*(2317) in DK scattering and the hyperon Λ(1405) in K¯N scattering, one bound state below the ΞccK¯ threshold is predicted in the (S,I)=(−1,0) channel. In addition, two resonant structures are found in the Ξccπ,Ξccη, and ΩccK coupled-channel scattering with (S,I)=(0,1/2). The corresponding pole positions and coupling strengths of the excited doubly charmed baryons are given. The scattering lengths of the ground-state doubly charmed baryons and light pseudoscalar mesons are also predicted. The current study may provide useful guides for future experimental measurements and lattice simulations.
Since December 2019, novel coronavirus infected pneumonia emerged in Wuhan city and rapidly spread throughout China. In severe novel coronavirus pneumonia cases, the number of platelets, their ...dynamic changes during the treatment, platelet‐to‐lymphocyte ratio (PLR) were a concern. We sought to describe the platelet feature of these cases. Single‐center case series of the 30 hospitalized patients with confirmed coronavirus disease (COVID)‐19 in Huizhou municipal central hospital from January 2020 to February 2020 were retrospectively analyzed. Demographic, clinical, blood routine results, other laboratory results, and treatment data were collected and analyzed. Outcomes of severe patients and nonsevere patients were compared. Univariate analysis showed that: age, platelet peaks, and PLR at peak platelet were the influencing factors in severe patients, multivariate analysis showed that the PLR value at peak platelet during treatment was an independent influencing factor in severe patients. The average hospitalization day of patients with platelet peaks during treatment was longer than those without platelet peaks (P < .05). The average age of patients with platelet peaks during treatment was older than those without platelet peaks (P < .05). The patients with significantly elevated platelets during treatment had longer average hospitalization days. And the higher PLR of patients during treatment had longer average hospitalization days. Single‐center case series of the 30 hospitalized patients with confirmed COVID‐19 in Huizhou Municipal Central Hospital, presumed that the number of platelets and their dynamic changes during the treatment may have a suggestion on the severity and prognosis of the disease. The patient with markedly elevated platelets and longer average hospitalization days may be related to the cytokine storm. The PLR of patients means the degree of cytokine storm, which might provide a new indicator in the monitoring in patients with COVID‐19.
Asymmetric hydroxycarbonylation is one of the most fundamental yet challenging methods for the synthesis of carboxylic acids. Herein, we reported the development of a palladium‐catalyzed highly ...enantioselective Markovnikov hydroxycarbonylation of vinyl arenes with CO and water. A monodentate phosphoramidite ligand L6 plays vital role in the reaction. The reaction tolerates a range of functional groups, and provides a facile and atom‐economical approach to an array of 2‐arylpropanoic acids including several commonly used non‐steroidal anti‐inflammatory drugs. The catalytic system has also enabled an asymmetric Markovnikov hydroalkoxycarbonylation of vinyl arenes with alcohols to afford 2‐arylpropanates. Mechanistic investigations suggested that the hydropalladation is irreversible and is the regio‐ and enantiodetermining step, while hydrolysis/alcoholysis is probably the rate‐limiting step.
A Pd‐catalyzed highly enantioselective Markovnikov hydroxycarbonylation of vinyl arenes with CO and water for the synthesis of 2‐arylpropanoic acids has been developed. Several non‐steroidal anti‐inflammatory drugs including ibuprofen, naproxen, flurbiprofen, fenoprofen, and ketoprofen were synthesized in high yields and ees in gram scale.
Visual pH-sensing films containing curcumin (CR) and anthocyanins (ATH) were prepared as on-package indicator labels for nondestructively detecting fish freshness in real time. Fourier transform ...infrared spectroscopy analysis indicated that CR and ATH were successfully immobilized into the film-forming substrate based on starch, polyvinyl alcohol (SPVA) and glycerol. The incorporation of different natural dyes had no significant effect on moisture content, water solubility, water vapor permeability and thickness of colorimetric films. Results of color stability test illustrated that the composite films incorporated with CR were the most stable and the composite film incorporated with ATH was least stable at room temperature for 180 days. The colorimetric film without glycerol was found less sensitive to volatile ammonia. Based on the volatile amines released by fish, an application trial of five colorimetric films containing natural dyes was conducted in bighead carp (Hypophthalmichthys nobilis) at 4 °C. Results showed that the SPVA/glycerol film incorporated with CR and ATH at a ratio of 2:8 (v/v) could provide three different colors, which were assigned to the sign of freshness, medium freshness, and spoilage for packaged fish. Hence, this colorimetric film can be applied as a promising material of intelligent packaging for non-destructively monitoring the real-time freshness of fish products.
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•Five different films were incorporated with anthocyanins, curcumin and their mixed dyes.•Films respond via visible color change to volatiles in the package headspace.•SPVAG/ATH/CR film can discriminate fresh, medium fresh, and spoiled bighead carp.
The contribution of biomechanical factors in the formation of proximal contact loss has been observed, but there is little research on the mechanisms by which they contribute. Using finite element ...analysis, this study aimed to analyse the impact of bone quality on the biomechanical behaviour of a dentition consisting of implant prostheses and adjacent teeth. The occlusal load was applied on the implant/tooth crown. In the mesiodistal direction, the adjacent natural tooth mesially to the implant denture had the tendency for mesial movement, while the distal adjacent natural tooth had the tendency for distal movement. For the supporting bone around the mesial adjacent tooth, the maximum/minimum principal stress and strain values on the mesial side of the bone were higher than those on the distal side of the bone. Stress and strain values on the mesial side of the supporting bone around the distal adjacent tooth were lower than those on the distal side. With decreasing bone density, displacements of teeth and the implant denture, principal stresses and equivalent strains on tooth supporting bone increased. Studies on biomechanical behaviours of a tooth‐implant dentition may provide a deeper understanding of implant‐induced dental adaptive processes such as proximal contact loss.
Complex continuous optimization problems widely exist nowadays due to the fast development of the economy and society. Moreover, the technologies like Internet of things, cloud computing, and big ...data also make optimization problems with more challenges including
M
any-dimensions,
M
any-changes,
M
any-optima,
M
any-constraints, and
M
any-costs. We term these as 5-M challenges that exist in large-scale optimization problems, dynamic optimization problems, multi-modal optimization problems, multi-objective optimization problems, many-objective optimization problems, constrained optimization problems, and expensive optimization problems in practical applications. The evolutionary computation (EC) algorithms are a kind of promising global optimization tools that have not only been widely applied for solving traditional optimization problems, but also have emerged booming research for solving the above-mentioned complex continuous optimization problems in recent years. In order to show how EC algorithms are promising and efficient in dealing with the 5-M complex challenges, this paper presents a comprehensive survey by proposing a novel taxonomy according to the function of the approaches, including
reducing problem difficulty
,
increasing algorithm diversity
,
accelerating convergence speed
,
reducing running time
, and
extending application field
. Moreover, some future research directions on using EC algorithms to solve complex continuous optimization problems are proposed and discussed. We believe that such a survey can draw attention, raise discussions, and inspire new ideas of EC research into complex continuous optimization problems and real-world applications.
Herein we present a new viologen‐based radical‐containing metal–organic framework (RMOF) Gd‐IHEP‐7, which upon heating in air undergoes a single‐crystal‐to‐single‐crystal transformation to generate ...Gd‐IHEP‐8. Both RMOFs exhibit excellent air and water stability as a result of favorable radical‐radical interactions, and their long‐lifetime radicals result in wide spectral absorption in the range 200–2500 nm. Gd‐IHEP‐7 and Gd‐IHEP‐8 show excellent activity toward solar‐driven nitrogen fixation, with ammonia production rates of 128 and 220 μmol h−1 g−1, respectively. Experiments and theoretical calculations indicate that both RMOFs have similar nitrogen fixation pathways. The enhanced catalytic efficiency of Gd‐IHEP‐8 versus Gd‐IHEP‐7 is attributed to intermediates stabilized by enhanced hydrogen bonding.
A single‐crystal‐to‐single‐crystal (SCSC) transformation of stable radical‐containing MOF Gd‐IHEP‐7 generates Gd‐IHEP‐8. It is accompanied by a marked increase in efficiency of sacrificial agent‐free photocatalytic nitrogen fixation to yield NH3 from H2O and N2 under simulated solar light irradiation at ambient temperature. The NH3 production rate of 220 μmol h−1 g−1 for Gd‐IHEP‐8 is a new record for MOF photocatalysts.
Breast cancer (BC) is a common malignancy worldwide. More than 3 700 000 women die of BC every year. DSCAM‐AS1 was overexpressed several kinds of cancer and miR‐204‐5p was lowly expressed, which ...indicated that miR‐204‐5p had anti‐tumor activity and DSCAM‐AS1 had pro‐tumor activity. We intended to analyze DSCAM‐AS1, miR‐204‐5p, and ribonucleotide reductase M2 (RRM2). Microarray analysis and quantitative Real Time fluorescence Polymerase Chain Reaction (qRT‐PCR) were employed to determine DSCAM‐AS1 and miR‐204‐5p expression. Luciferase reporter assay was applied to examine the target relationship between DSCAM‐AS1, miR‐204‐5p, and RRM2. Cell Counting Kit‐8 (CCK‐8 assay), transwell assay, and flow cytometry were used to detect cell proliferation, invasion, and apoptosis. The expression of DSCAM‐AS1, miR‐204‐5p, and RRM2 were confirmed by Western blot. We also conducted in vivo assay to verify the effect of DSCAM‐AS1. DSCAM‐AS1 was up‐regulated, while miR‐204‐5p was down‐regulated in BC tissues and cells. DSCAM‐AS1 directly targeted miR‐204‐5p. DSCAM‐AS1 promoted the proliferation and invasion of BC cells by reducing miR‐204‐5p and inhibiting miR‐204‐5p expression. DSCAM‐AS1 expression was related to the expression of RRM2, and miR‐204‐5p could reverse the function of DSCAM‐AS1. RRM2 was up‐regulated in BC cells, and miR‐204‐5p inhibited RRM2 expression by targeting RRM2. Overexpression of RRM2 stimulated proliferation and cell invasion and impeded apoptosis. In vivo experiments showed that knockdown of DSCAM‐AS1 decreased the tumorigenesis of BC cells, increased the expression of miR‐204‐5p. DSCAM‐AS1 promoted proliferation and impaired apoptosis of BC cells by reducing miR‐204‐5p and enhancing RRM2 expression. DSCAM‐AS1/miR‐204‐5p/RRM2 may serve as novel therapeutic targets for BC.
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