Fe3O4-lignin@Pd-NPs: A highly active, stable and broad-spectrum nanocomposite for water treatment.

In this work, we report an environmentally friendly renewable nanocomposite magnetic lignin-based palladium nanoparticles (Fe3O4-lignin@Pd-NPs) for efficient wastewater treatment by decorating palladium nanoparticles without using any toxic reducing agents on the magnetic lignin abstracted from Poplar. The structure of composite Fe3O4-lignin@Pd-NPs was unambiguously confirmed by XRD, SEM, TEM, EDS, FTIR, and Zeta potential. After systematic evaluation of the use and efficiency of the composite to remove toxic organic dyes in wastewater, some promising results were observed as follows: Fe3O4-lignin@Pd-NPs exhibits highly active and efficient performance in the removal of toxic methylene blue (MB) (up to 99.8 %) wastewater in 2 min at different concentrations of MB and different pH values. Moreover, except for toxic MB, the other organic dyes including Rhodamine B (RhB), Rhodamine 6G (Rh6G), and Methyl Orange (MO) can also be removed efficiently by the composite. Finally, the easily recovered composite Fe3O4-lignin@Pd-NPs exhibits well stability and reusability, and catalytic efficiency is maintained well after ten cycles. In conclusion, the lignin-based magnetism Pd composite exhibits powerful potential practical application in industrial wastewater treatment.

Enhanced Photodynamic of Carriers and Suppressed Charge Recombination Enable Approaching 18% Efficiency in Nonfullerene Organic Solar Cells.

Regulation of the exciton generation, diffusion, and carrier transport, as well as optimization of the non-radiative energy loss could further overcome the power conversion efficiency limitation of organic solar cells. However, the relationship between exciton properties and non-radiative energy loss has seldom been investigated. Herein, taking D18-series devices as the research model, the exciton diffusion length (LD) and hole transfer dynamics can be remarkably improved by the variation of electron-withdrawing halogen and the non-radiative energy loss simultaneously can be suppressed. By combining the analysis results of hole transfer, exciton diffusion, charge separation, and recombination, this work demonstrates that the photo-induced exciton in the chlorinated polymer donor can diffuse to a longer distance within the effective exciton lifetime, suppress the exciton recombination, and enhance device performance. The results define the relationship between the exciton behaviors and non-radiative energy loss and further reveal the significance of controlling the bulk heterojunction with superior photo-physical properties.

Unexpected Cascade Dehydrogenation Triggered by Pd/Cu-Catalyzed C(sp3)-H Arylation/Intramolecular C-N Coupling of Amides: Facile Access to 1,2-Dihydroquinolines.

In this work, we successfully explored an unexpected dehydrogenation triggered by Pd/Cu-catalyzed C(sp3)-H arylation and intramolecular C-N coupling of amides to synthesize the bioactive 1,2-dihydroquinoline scaffold with good regioselectivity and good compatibility of functional groups. This strategy provides an alternative route to realize molecular complexity and diversity from simple and readily available molecules via multiple C-H bond activation. Preliminary mechanistic studies demonstrated that ß,γ-dehydrogenation is triggered by the arylation of the C(sp3)-H bond and the intramolecular C-N coupling.

Flavanthrene derivatives as photostable and efficient singlet exciton fission materials.

Singlet exciton fission (SF) is believed to have the potential to break the Shockley-Queisser limit for third-generation solar cell devices, so it has attracted great attention. Conventional linear acene based SF materials generally suffer from low triplet energy and poor photostability. We report herein two flavanthrene derivatives, EH-Fla and TIPS-Fla, as new photostable singlet exciton fission materials. These N-doped two-dimensional angular fused acenes have three sets of aromatic Clar sextets, making them significantly more stable than linear acenes with only one sextet. Time-resolved spectroscopy characterization reveals that the SF process occurs in the polycrystalline films of EH-Fla and TIPS-Fla, with maximal triplet yields of 32% and 159%, respectively. The SF processes of these two molecules are mediated by excimer states. In EH-Fla, the low-lying excimer prevents the SF process from occurring effectively, resulting in a low triplet yield. In contrast, the excimer state in TIPS-Fla is mixed with strong CT coupling, which prompts efficient SF and results in a high triplet yield. Our results show that flavanthrene is a promising SF chromophore for photoenergy conversion applications, while a fine-tune of the intermolecular interaction is crucial for achieving high SF efficiency.

Artificial intelligence for prediction of COVID-19 progression using CT imaging and clinical data.

OBJECTIVES: Early recognition of coronavirus disease 2019 (COVID-19) severity can guide patient management. However, it is challenging to predict when COVID-19 patients will progress to critical illness. This study aimed to develop an artificial intelligence system to predict future deterioration to critical illness in COVID-19 patients. METHODS: An artificial intelligence (AI) system in a time-to-event analysis framework was developed to integrate chest CT and clinical data for risk prediction of future deterioration to critical illness in patients with COVID-19. RESULTS: A multi-institutional international cohort of 1,051 patients with RT-PCR confirmed COVID-19 and chest CT was included in this study. Of them, 282 patients developed critical illness, which was defined as requiring ICU admission and/or mechanical ventilation and/or reaching death during their hospital stay. The AI system achieved a C-index of 0.80 for predicting individual COVID-19 patients' to critical illness. The AI system successfully stratified the patients into high-risk and low-risk groups with distinct progression risks (p < 0.0001). CONCLUSIONS: Using CT imaging and clinical data, the AI system successfully predicted time to critical illness for individual patients and identified patients with high risk. AI has the potential to accurately triage patients and facilitate personalized treatment. KEY POINT: • AI system can predict time to critical illness for patients with COVID-19 by using CT imaging and clinical data.

Unveiling the dimension-dependence of femtosecond nonlinear optical properties of tellurium nanostructures.

Low dimensional tellurium is currently of great interest for potential electronic applications due to the experimentally observed Weyl fermions and the excellent carrier mobility, on/off ratios and current-carrying capacity in devices. However, the optical properties of Te nanostructures are not well explored, especially in the field of nonlinear optics. Here, we prepared a series of Te nanostructures by electrochemical exfoliation and liquid phase exfoliation methods, including one-dimensional (1D) Te nanowires (NWs), quasi-1D Te nanorods (NRs), zero-dimensional (0D) Te nanodots (NDs) and two-dimensional (2D) Te nanosheets (NSs). Femtosecond Z-scan measurements reveal unique dimension-dependent nonlinear optical (NLO) properties. 1D Te NWs and quasi-1D Te NRs exhibited higher saturable absorption behavior than 0D Te nanostructures, while the 2D Te NSs are a high performance optical limiting material. Ultrafast transient absorption spectroscopy revealed the dimension-dependent exciton dynamics. The reverse saturable absorption of 2D Te NSs is derived from faster exciton relaxation and stronger excited state absorption. This work paves the way for the design of saturable absorbers with high performance and broadens the application of 2D Te in the field of laser protection and other novel ultrafast photonics.

Tunable nonlinear optical responses and carrier dynamics of two-dimensional antimonene nanosheets.

Sb nanosheets, also known as antimonene, have received ever-growing consideration as a promising new type of two-dimensional (2D) material due to their many attractive properties. However, how their nonlinear optical (NLO) properties are affected by their nanosheet structure and measurement conditions remains unclear. Herein, we report a successful size-selective production method for Sb nanosheets, which is based on a combination of lithium ion intercalation, solvent exfoliation and size selection centrifugation. This high-yield and size-selective preparation method enables fundamental investigation on the relation of the intrinsic optical properties of Sb nanosheets. Nanosecond Z-scan measurements revealed a unique size-dependent broadband NLO response. When the average size is reduced from 3 micrometers to 50 nanometers, the Sb nanosheets exhibit a clear transition from saturable absorption to reversed saturable absorption. Ultrafast transient absorption spectroscopic investigation indicated that exciton cooling is significantly faster in a small nanosheet than in large ones, revealing that the different exciton relaxation dynamic plays key roles in the distinct size-tunable nonlinear optical response. This work paves new ways towards the mass production and practical application of antimonene.

Artificial Intelligence Augmentation of Radiologist Performance in Distinguishing COVID-19 from Pneumonia of Other Origin at Chest CT.

Background Coronavirus disease 2019 (COVID-19) and pneumonia of other diseases share similar CT characteristics, which contributes to the challenges in differentiating them with high accuracy. Purpose To establish and evaluate an artificial intelligence (AI) system for differentiating COVID-19 and other pneumonia at chest CT and assessing radiologist performance without and with AI assistance. Materials and Methods A total of 521 patients with positive reverse transcription polymerase chain reaction results for COVID-19 and abnormal chest CT findings were retrospectively identified from 10 hospitals from January 2020 to April 2020. A total of 665 patients with non-COVID-19 pneumonia and definite evidence of pneumonia at chest CT were retrospectively selected from three hospitals between 2017 and 2019. To classify COVID-19 versus other pneumonia for each patient, abnormal CT slices were input into the EfficientNet B4 deep neural network architecture after lung segmentation, followed by a two-layer fully connected neural network to pool slices together. The final cohort of 1186 patients (132 583 CT slices) was divided into training, validation, and test sets in a 7:2:1 and equal ratio. Independent testing was performed by evaluating model performance in separate hospitals. Studies were blindly reviewed by six radiologists without and then with AI assistance. Results The final model achieved a test accuracy of 96% (95% confidence interval [CI]: 90%, 98%), a sensitivity of 95% (95% CI: 83%, 100%), and a specificity of 96% (95% CI: 88%, 99%) with area under the receiver operating characteristic curve of 0.95 and area under the precision-recall curve of 0.90. On independent testing, this model achieved an accuracy of 87% (95% CI: 82%, 90%), a sensitivity of 89% (95% CI: 81%, 94%), and a specificity of 86% (95% CI: 80%, 90%) with area under the receiver operating characteristic curve of 0.90 and area under the precision-recall curve of 0.87. Assisted by the probabilities of the model, the radiologists achieved a higher average test accuracy (90% vs 85%, Δ = 5, P < .001), sensitivity (88% vs 79%, Δ = 9, P < .001), and specificity (91% vs 88%, Δ = 3, P = .001). Conclusion Artificial intelligence assistance improved radiologists' performance in distinguishing coronavirus disease 2019 pneumonia from non-coronavirus disease 2019 pneumonia at chest CT. © RSNA, 2020 Online supplemental material is available for this article.

Pd/Cu-Catalyzed Cascade C(sp3)-H Arylation and Intramolecular C-N Coupling: A One-Pot Synthesis of 3,4-2 H-Quinolinone Skeletons.

In this letter, we successfully explored a cascade Pd/Cu-catalyzed intermolecular C(sp3)-H arylation of amides and intramolecular C-N coupling reaction. This method provides a one-pot strategy to synthesize 3,4-2 H-quinolinone with good regioselectivity of C-H arylation and C-N coupling from C-I and C-X bonds from readily available starting materials.

Faecalibacterium prausnitzii supernatant ameliorates dextran sulfate sodium induced colitis by regulating Th17 cell differentiation.

AIM: To explore the preventive and therapeutic effects of Faecalibacterium prausnitzii (F. prausnitzii) supernatant on dextran sulfate sodium (DSS) induced colitis in mice. METHODS: Forty C57BL/6J male mice were randomly divided into four groups: control group, model group, treatment group, and prevention group. Mice were weighed daily. On day 10, the colon length was measured, the colorectal histopathologic damage score (HDS) was assessed, and plasma interleukin (IL)-17A, IL-6, and IL-4 levels were detected by enzyme-linked immunosorbent assay. The expression of transcription factor retinoic acid-related orphan receptor-γt (RORγt) and IL-17A in colon inflammatory mucosa tissue were determined by immunohistochemical assay, and the expression levels of RORγt mRNA, IL-17A mRNA, and IL-6 mRNA were detected by real-time quantitative polymerase chain reaction (PCR). The proportion of Th17 in mononuclear cells in spleen was assayed by fluorescence activated cell sorter. RESULTS: When compared with the model group, the colon length (P < 0.05) and body weight (P < 0.01) in the treatment and prevention groups were significantly increased, and the colon HDS was decreased (P < 0.05 and P < 0.01). There was no statistical difference between the treatment group and prevention group. After treatment with F. prausnitzii supernatant, the plasma levels of IL-17A and IL-6 (P < 0.05), the protein and mRNA expression of IL-17A and RORγt, and the Th17 cell ratio of spleen cells (P < 0.01) were significantly decreased compared to the model group. Plasma IL-4 level in the prevention group was significantly higher than that in the model group (P < 0.05), but there was no significant difference between these two groups in the expression of IL-6 in both the plasma and colon mucosa tissues. CONCLUSION: F. prausnitzii supernatant exerts protective and therapeutic effects on DSS-induced colitis in mice, probably via inhibition of Th17 differentiation and IL-17A secretion in the plasma and colon mucosa tissues. It can also improve colitis in mice by downregulating IL-6 and prevent colitis by upregulating IL-4.

Cu-Catalyzed Alkynylation of Unactivated C(sp(3))-X Bonds with Terminal Alkynes through Directing Strategy.

In this letter, we report an efficient and concise protocol for Cu-catalyzed cross-coupling of unactivated alkyl halides/peusudohalides with terminal alkynes to afford internal alkynes with the assistance of various amides as directing groups. Different alkyl halides/pseudohalides exhibited excellent reactivities, and the inactivated alkyl chlorides and sulfonates showed better reactivity than bromides/iodides. This is the first successful example to apply alkyl chlorides and sulfonates directly in cross-coupling with terminal alkynes in the absence of any additives. A Cu catalyst was found to be more effective than other transition metal catalysts. This reaction also exhibited a broad substrate scope with respect to terminal alkynes.

Silver-Catalyzed Long-Distance Aryl Migration from Carbon Center to Nitrogen Center.

Selective cleavage of an inert C-C bond followed by C-O/N bond formation through a long-distance aryl migration from a carbon to a nitrogen center via Ag catalysis is reported. The migration products were easily converted into γ-hydroxy amines and tetrahydroquinoline derivatives in quantitative yields. Preliminary mechanistic studies indicated a radical pathway.

Synthesis of dibenzo[c,e]oxepin-5(7H)-ones from benzyl thioethers and carboxylic acids: rhodium-catalyzed double C-H activation controlled by different directing groups.

A rhodium(III)-catalyzed cross-coupling of benzyl thioethers and aryl carboxylic acids through the two directing groups is reported. Useful structures with diverse substituents were efficiently synthesized in one step with the cleavage of four bonds (CH, CS, OH) and the formation of two bonds (CC, CO). The formed structure is the privileged core in natural products and bioactive molecules. This work highlights the power of using two different directing groups to enhance the selectivity of a double CH activation, the first of such examples in cross-oxidative coupling.

Synthesis of dibenzopyranones through palladium-catalyzed directed C-H activation/carbonylation of 2-arylphenols.

Dibenzopyranones were synthesized by a palladium-catalyzed phenol-directed C-H activation/carbonylation of 2-phenylphenol derivatives in the presence of CO. Pd(OAc)2 was used as a catalyst and Cu(OAc)2 as a catalytic oxidant in the presence of air.

Synthesis and structural characterization of some new porphyrin-fullerene dyads and their application in photoinduced H2 evolution.

The [3 + 2] cycloaddition reaction of C(60) with ethyl isonicotinoylacetate in the presence of piperidine in PhCl at room temperature or in the presence of Mn(OAc)(3) in refluxing PhCl gave the pyridyl-containing dihydrofuran-fused C(60) derivative (4-C(5)H(4)N)C(O)═C(C(60))CO(2)Et (1), whereas the phenyl-containing C(60) derivative PhC(O)═C(C(60))CO(2)Et (2) was similarly prepared by [3 + 2] cycloaddition reaction of C(60) with ethyl benzoylacetate in the presence of piperidine or Mn(OAc)(3). More interestingly, one of the new porphyrin-fullerene dyads, i.e., [4-C(5)H(4)NC(O)═C(C(60))CO(2)Et]·ZnTPPH (3, ZnTPPH = tetraphenylporphyrinozinc), could be prepared by coordination reaction of the pyridyl-containing C(60) derivative 1 with equimolar ZnTPPH in CS(2)/hexane at room temperature. In addition, the ß-keto ester-substituted porphyrin derivative H(2)TPPC(O)CH(2)CO(2)Et (4) was prepared by a sequential reaction of HO(2)CCH(2)CO(2)Et with n-BuLi in 1:2 molar ratio followed by treatment with H(2)TPPC(O)Cl in the presence of Et(3)N and then hydrolysis with diluted HCl, whereas the porphyrinozinc derivative ZnTPPC(O)CH(2)CO(2)Et (5) could be prepared by coordination reaction of 4 with Zn(OAc)(2) in refluxing CHCl(3)/MeOH. Particularly interesting is that the second new porphyrin-fullerene dyad H(2)TPPC(O)═C(C(60))CO(2)Et (6) could be prepared by [3 + 2] cycloaddition reaction of 4 with C(60) in the presence of piperidine in PhCl at room temperature. In addition, treatment of 6 with Zn(OAc)(2) in refluxing CHCl(3)/MeOH afforded the third new dyad ZnTPPC(O)═C(C(60))CO(2)Et (7). All the new compounds 1-7 were characterized by elemental analysis and various spectroscopic methods and particularly for 2, 3, and 5 by X-ray crystallography. The five-component system consisting of an electron donor EDTA, dyad 3, an electron mediator methylviologen (MV(2+)), the catalyst colloidal Pt, and a proton source HOAc was proved to be effective for photoinduced H(2) evolution. A possible pathway for such a type of H(2) evolution was proposed.

Synthesis and herbicidal activity of isoindoline-1,3-dione substituted benzoxazinone derivatives containing a carboxylic ester group.

A carboxylic ester group was introduced to three series of isoindolinedione substituted benzoxazinone derivatives. Some of these analogues exhibited good herbicidal activities, and the injury symptoms against weeds included leaf cupping, crinkling, bronzing, and necrosis, typical of protox inhibitor herbicides. Structurally, they were classified as Chemical Group A (4-carboxylic ester group-6-isoindolinyl-benzoxazinones), B (4-carboxylic ester group-7-isoindolinyl-benzoxazinones), and C (4-carboxylic ester group-6- tetrahydroisoindolinyl-benzoxazinones). All of the tested compounds were structurally confirmed by (1)H NMR, IR, mass spectroscopy, and elemental analysis. Preliminary bioassay data of these three classes of compounds showed that, in general, the order of the herbicidal effectiveness is C > A > B. Several of the lead compounds, for example, C10 (methyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2-methyl-3-oxo-2H-benzo[b][1,4] oxazin-4(3H)-yl) propano-ate), C12 (ethyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2- methyl-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl) propanoate), and C13 (ethyl 2-(6-(1,3-dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-2-methyl-3-oxo-2H-benzo-[b][1,4]oxazin-4(3H)-yl) butanoate), exhibited greater than 80% control at 75 g a.i./ha in both pre- and postemergence treatments against dicotyledonous weeds, such as Abutilon theophrasti Medic, Chenopodium album L., and Amaranthus ascendens L., and monocotyledon weeds, such as Digitaria sanguinalis L., Echinochloa crus-galli L., and Setaria viridis L. On the basis of advanced screening tests and crop selectivity, compounds C10, C12, and C13 are safer to crops than flumioxazin. Compounds C10, C12, and C13 are potent to develop as pre-emergent herbicides used in peanut, soybean, maize, and cotton fields.