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1.
Insect Sci ; 2022 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-34997945

RESUMO

Insect midgut plays a central role in food digestion and nutrition absorption. Larval silkworm midgut could be divided into three distinct regions based on their morphological colors. However, it remains rudimentary of regional gene expression and physiological function in larval silkworm midgut. Through transcriptome sequencing of three midgut compartments, a comprehensive analysis of gene expression atlas along the anterior-posterior axis was conducted. Posterior midgut was found transcriptionally divergent from anterior and middle midgut. Differentially expressed gene (DEG) analysis revealed the regional specialization of digestive enzyme production, transmembrane transport, chitin metabolism, and hormone regulation in different midgut regions. In addition, gene subsets of pan-midgut and region-specific transcription factors (TFs) along the length of midgut were also identified. The results suggested that homeobox TFs might play an essential role in transcriptional variations across the midgut. Altogether, our study provided the first fundamental resource to investigate physiological function and regulation mechanism in larval midgut compartmentalization. This article is protected by copyright. All rights reserved.

2.
J Healthc Eng ; 2022: 6107940, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35028122

RESUMO

Lung cancer is one of the malignant tumors with the highest fatality rate and nearest to our lives. It poses a great threat to human health and it mainly occurs in smokers. In our country, with the acceleration of industrialization, environmental pollution, and population aging, the cancer burden of lung cancer is increasing day by day. In the diagnosis of lung cancer, Computed Tomography (CT) images are a fairly common visualization tool. CT images visualize all tissues based on the absorption of X-rays. The diseased parts of the lung are collectively referred to as pulmonary nodules, the shape of nodules is different, and the risk of cancer will vary with the shape of nodules. Computer-aided diagnosis (CAD) is a very suitable method to solve this problem because the computer vision model can quickly scan every part of the CT image of the same quality for analysis and will not be affected by fatigue and emotion. The latest advances in deep learning enable computer vision models to help doctors diagnose various diseases, and in some cases, models have shown greater competitiveness than doctors. Based on the opportunity of technological development, the application of computer vision in medical imaging diagnosis of diseases has important research significance and value. In this paper, we have used a deep learning-based model on CT images of lung cancer and verified its effectiveness in the timely and accurate prediction of lungs disease. The proposed model has three parts: (i) detection of lung nodules, (ii) False Positive Reduction of the detected nodules to filter out "false nodules," and (iii) classification of benign and malignant lung nodules. Furthermore, different network structures and loss functions were designed and realized at different stages. Additionally, to fine-tune the proposed deep learning-based mode and improve its accuracy in the detection Lung Nodule Detection, Noudule-Net, which is a detection network structure that combines U-Net and RPN, is proposed. Experimental observations have verified that the proposed scheme has exceptionally improved the expected accuracy and precision ratio of the underlined disease.

3.
Org Lett ; 24(1): 451-456, 2022 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-34931845

RESUMO

The selective and effective conversion of low-cost and simple bulk chemicals into high value-added products through catalytic strategy has a wide range of practical significance. Here, a palladium-catalyzed method for the direct and efficient dicarbonylation of amines with basic industrial feedstock ethylene to imide has been developed. Moderate to excellent yields of the desired imides can be produced from readily available amines in a straightforward manner.

4.
Chemosphere ; : 133187, 2021 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-34890625

RESUMO

Mussels are often used as biological indicators for monitoring marine microplastic pollution. The crucial procedure during monitoring is the separation of microplastics from mussel samples. We investigated the separation efficiencies of six combinations of two digestion solutions (10% KOH and 30% H2O2) and three extraction solutions (NaCl, oil in H2O, and oil in NaCl) for mussels with low- and high-density microplastics. After KOH digestion, no polyethylene terephthalate (PET) could be extracted using the three extraction solutions, which might be due to the degradation of PET. After H2O2 digestion, the total extraction recovery rates of polypropylene, polyvinyl chloride, and PET for oil in H2O and oil in NaCl solution ranged from 95.6% ±â€¯5.09%-100%, which were higher than those of the saturated NaCl solution (51.1% ±â€¯17.1%-67.8% ±â€¯13.9%). The first extraction recovery rates of oil in NaCl solution for PP, PET, and PVC were higher than those of oil in H2O. In this study, extraction by oil in NaCl solution after 30% H2O2 digestion was suggested to separate microplastics from mussels. This method is conducive to promoting the standardization of microplastic monitoring in mussels and might be suitable for large-scale monitoring of marine microplastic pollution.

5.
Chem Soc Rev ; 2021 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-34951429

RESUMO

As the main biomarkers of most diseases, enzymes play fundamental but extremely critical roles in biosystems. High-resolution studies of enzymes using activatable in situ fluorescence imaging may help to better elucidate their dynamics in living systems. Currently, most activatable probes can realize changeable imaging of enzymes but inevitably tend to diffuse away from the original active site of the enzyme and even translocate out of cells, seriously impairing in situ high-resolution observation of the enzymes. In situ fluorescence imaging of enzymes can be realized by labelling probes or antibodies with always-on signals that fail to enable activatable imaging of enzymes. Thus, fluorescent probes with both "activatable" and "in situ" properties will enable high-resolution studies of enzymes in living systems. In this tutorial review, we summarize the existing methods ranging from design strategies to bioimaging applications that could be used to develop activatable fluorescent probes for in situ imaging of enzymes. It is expected that this tutorial review will promote the new methods generated to design such probes for better deciphering enzymes in complex biosystems and further extend the application of these methods to other fields of enzymes.

6.
Artigo em Inglês | MEDLINE | ID: mdl-34971410

RESUMO

Purpurogallin is a natural benzotropolone extracted from Quercus spp, which has antioxidant, anticancer, and anti-inflammatory properties. Purpurogallin is typically synthesized from pyrogallol using enzymatic or metal catalysts, neither economically feasible nor environmentally friendly. 3-Methoxycatechol (3-MC) is a lignin-derived renewable chemical with the potential to be a substrate for the biosynthesis of purpurogallin. In this study, we designed a pathway to produce purpurogallin from 3-MC. We first characterized four bacterial laccases and identified the laccase CueO from Escherichia coli, which converts pyrogallol to purpurogallin. Then, we used CueO and the P450 GcoAB reported to convert 3-MC to pyrogallol, to construct a method for producing purpurogallin directly from 3-MC. A total of 0.21 ± 0.05 mM purpurogallin was produced from 5 mM 3-MC by whole-cell conversion. This study provides a new method to enable efficient and sustainable synthesis of purpurogallin and offers new insights into lignin valorization. KEY POINTS: • Screening four bacterial laccases for converting pyrogallol to purpurogallin. • Laccase CueO from Escherichia coli presenting the activity for purpurogallin yield. • A novel pathway for converting lignin-derived 3-methoxycatechol to purpurogallin.

7.
Gene ; 814: 146129, 2021 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-34971751

RESUMO

One of the amazing phenomena in the baculovirus life cycle is the hyperexpression of the very late gene, polyhedrin (polh), causing the production of the occlusion bodies where progeny virions are embedded. However, to date, the molecular mechanism underlying its hyperexpression is not completely elucidated. Considering that, in this review, the mechanism responsible for its hyperexpression from the previous studies up to now was comprehensively summarized from three aspects, namely, the structure characteristics of the polh promoter and transcription regulation, the structure and translation regulation of the polh mRNA, and especially the regulators that influence the expression of polh gene. Moreover, this review will help us obtain a better understanding about the hyperexpression of polh, and also provide guidance for improving the expression efficiency of the foreign proteins by adopting the baculovirus expression vector system.

8.
Gene ; 813: 146121, 2021 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-34915049

RESUMO

Lipases play crucial roles in food digestion by degrading dietary lipids into free fatty acids and glycerols. The domesticated silkworm (Bombyx mori) has been widely used as an important Lepidopteran model for decades. However, little is known about the lipase gene family in the silkworm, especially their hydrolytic activities as digestive enzymes. In this study, a total of 38 lipase genes were identified in the silkworm genome. Phylogenetic analysis indicated that they were divided into three major groups. Twelve lipases were confirmed to be expressed in the midgut at both transcriptional and translational levels. They were grouped into the same gene cluster, suggesting that they could have similar physiological functions. Quantitative real-time PCR (qRT-PCR) analyses indicated that lipases were mainly expressed in anterior and middle midgut regions, and their expression levels varied greatly along the length of midgut. A majority of lipases were down-regulated in the midgut when larvae stopped feeding. However, a unique lipase gene (Bmlip10583) showed low expression level during feeding stage, but it was significantly up-regulated during the larvae-pupae transition. These results demonstrated that expression of silkworm lipases was spatially and temporally regulated in the midgut during larval development. Taken together, our results provide a fundamental research of the lipase gene family in the silkworm.

9.
Chem Sci ; 12(44): 14937-14943, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34820110

RESUMO

Hydroformylation catalyzed by transition metals is one of the most important homogeneously catalyzed reactions in industrial organic chemistry. Millions of tons of aldehydes and related chemicals are produced by this transformation annually. However, most of the applied procedures use rhodium catalysts. In the procedure described here, a copper-catalyzed hydroformylation of alkenes has been realized. Remarkably, by using a different copper precursor, the aldehydes obtained can be further hydrogenated to give the corresponding alcohols under the same conditions, formally named as hydroxymethylation of alkenes. Under pressure of syngas, various aldehydes and alcohols can be produced from alkenes with copper as the only catalyst, in excellent regioselectivity. Additionally, an all-carbon quaternary center containing ethers and formates can be synthesized as well with the addition of unactivated alkyl halides. A possible reaction pathway is proposed based on our results.

10.
Nanotechnology ; 33(9)2021 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-34808610

RESUMO

Oxygen vacancies are considered to be an important factor to influence the electronic structure and charge transport of electrocatalysts in the field of energy chemistry. Various strategies focused on oxygen vacancy engineering are proved to be efficient for further improving the electrocatalytic performance of Co3O4. Herein, an optimal Co3O4with rich oxygen vacancies have been synthesized via a two-step process combining solution reduction and Ni2+impregnation. The as-prepared electrocatalyst exhibits an enhanced oxygen evolution performance with the overpotential of 330 mV at the current density of 10 mA cm-2in alkaline condition, which is 84 mV lower than that of pristine one. With the increasing of oxygen vacancies, the charge transfer efficiency and surface active area are relatively enhanced reflected by the Tafel slope and double-layer capacitance measurement. These results indicate that combination of solution reduction and heteroatom doping can be a valid way for efficient metal oxides-based electrocatalyst development by constructing higher concentration of oxygen vacancy.

12.
Chem Sci ; 12(41): 13777-13781, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34760162

RESUMO

The construction of structurally complexed and high-value chemical molecules from simple and readily available feedstocks is a long-standing challenge to chemists. Here, we describe a copper-catalyzed borofunctionalization of styrenes with B2pin2 and carbon monoxide. A set of new sodium cyclic borates were obtained with NaO t Bu as the base. These unique sodium cyclic borates can be easily converted into a variety of multifunctional ß-boryl vinyl esters, boryl carbonates, ß-boryl aldehydes, and boryl vinyl ether. In addition, the procedure also features good functional group tolerance and utilizes CO as the C1 source.

13.
J Am Chem Soc ; 143(46): 19446-19453, 2021 Nov 24.
Artigo em Inglês | MEDLINE | ID: mdl-34731564

RESUMO

Development of new porous materials as hosts to suppress the dissolution and shuttle of lithium polysulfides is beneficial for constructing highly efficient lithium-sulfur batteries (LSBs). Although 2D covalent organic frameworks (COFs) as host materials exhibit promising potential for LSBs, their performance is still not satisfactory. Herein, we develop polyimide COFs (PI-COF) with a well-defined lamellar structure, which can be exfoliated into ultrathin (∼1.2 nm) 2D polyimide nanosheets (PI-CONs) with a large size (∼6 µm) and large quantity (40 mg/batch). Explored as new sulfur host materials for LSBs, PI-COF and PI-CONs deliver high capacities (1330 and 1205 mA h g-1 at 0.1 C, respectively), excellent rate capabilities (620 and 503 mA h g-1 at 4 C, respectively), and superior cycling stability (96% capacity retention at 0.2 C for PI-CONs) by virtue of the synergy of robust conjugated porous frameworks and strong oxygen-lithium interactions, surpassing the vast majority of organic/polymeric lithium-sulfur battery cathodes ever reported. Our finding demonstrates that ultrathin 2D COF nanosheets with carbonyl groups could be promising host materials for LSBs with excellent electrochemical performance.

14.
Org Biomol Chem ; 19(44): 9654-9658, 2021 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-34734959

RESUMO

A Mn(III)-promoted thiocarbonylation procedure toward the synthesis of thioesters has been developed. By employing easily available disulfides and potassium alkyltrifluoroborates as the starting materials, and cheap and non-toxic Mn(OAc)3·2H2O as the promotor, a broad range of thioesters were synthesized in good to excellent yields via radical intermediates.

15.
Org Lett ; 23(20): 8062-8066, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34609152

RESUMO

A copper-catalyzed alkoxycarbonylation transformation of unactivated alkyl iodides has been developed. Various alkyl iodides can be converted into the corresponding tert-butyl esters in good yields. NaOtBu acts as both a nucleophile and a base. Moreover, other types of aliphatic esters can also be obtained in moderated yields if extra alcohols are added. Both primary and secondary alkyl alcohols can react successfully.

16.
Chemistry ; 2021 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-34617652

RESUMO

Transition-metal-catalyzed multicomponent carbonylation is one of the most efficient strategies to construct carbonyl-containing compounds. Herein, a palladium-catalyzed four-component perfluoroalkylation/aminocarbonylation of unactivated alkenes with perfluoroalkyl halides, and amines was developed. A wide range of substrates, including anilines, alkylamines, sulfonamides, and hydrazines are all suitable reaction partners for this catalyst system, resulting in various ß-perfluoroalkyl amides with good functional-group tolerance and excellent chemoselectivity. Furthermore, not only alkyl olefins, but also aliphatic alkynes, and even alkyl allenes can all be employed. Notably, several medical and bioactive related molecules are compatible here as well.

17.
Angew Chem Int Ed Engl ; 60(49): 25787-25792, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34622558

RESUMO

A novel copper-catalyzed carbonylative trifluoromethylation of unactivated alkenes has been developed. A broad range of ß-trifluoromethylated carboxylic acid derivatives were prepared in moderate to excellent yields from simple alkenes with excellent regioselectivity. It is noteworthy that ethylene gas, as the simplest olefin, can also be applied directly to obtain ß-trifluoromethylated amides and ester. This transformation presents the first example on carbonylative trifluoromethylation of alkenes.

18.
Chem Sci ; 12(38): 12676-12681, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34703553

RESUMO

Secondary amides are omnipresent structural motifs in peptides, natural products, pharmaceuticals, and agrochemicals. The copper-catalyzed enantioselective hydroaminocarbonylation of alkenes described in this study provides a direct and practical approach for the construction of α-chiral secondary amides. An electrophilic amine transfer reagent possessing a 4-(dimethylamino)benzoate group was the key to the success. This method also features broad functional group tolerance and proceeds under very mild conditions, affording a set of α-chiral secondary amides in high yields (up to 96% yield) with unprecedented levels of enantioselectivity (up to >99% ee). α,ß-Unsaturated secondary amides can also be produced though the method by using alkynes as the substrate.

19.
Chem Rec ; 2021 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-34591367

RESUMO

Carbonylative reactions by the using of CO surrogates constitute a facile avenue for the assembly of valuable carbonyl-containing compounds due to the colorless, toxic, flammable, and not easy-handing character of carbon monoxide gas. Recent advances in the carbonylative transformations with TFBen (benzene-1,3,5-triyl triformate) as a safe and convenient CO precursor are systematically summarized and discussed, which can be divided into three parts based on the patterns of the obtained products. This Review focuses on the discussion of the application of TFBen in carbonylative synthesis of various carbonyl-containing compounds.

20.
Org Biomol Chem ; 19(38): 8246-8249, 2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34515285

RESUMO

A palladium-catalyzed carbonylation of iminoquinones and aryl iodides has been developed for the construction of aryl p-amino benzoates. Using benzene-1,3,5-triyl triformate (TFBen) as the CO source, the reaction proceeded well to give various aryl p-amino benzoates in good to excellent yields. Additionally, control experiments were conducted to gain more insights into the reaction mechanism.

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