Publications by authors named "Meihua Shen"

An organoid is a cell-based structure that shows organ-specific properties and shares a similar spatial organization as the corresponding organ. Organoids possess powerful capability to reproduce the key functions of the associated organ structures, and their similarity to the organs makes them physiologically relevant systems. The primary challenge associated with the development of skin organoids is the complexity of the human skin architecture, which encompasses the epidermis and the dermis as well as accessory structures, including hair follicles, sweat glands, and sebaceous glands, that perform various functions such as thermoregulation.

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Background: The aim of this study was to investigate whether high-dose intravenous vitamin C (HDIVC) could decrease the mortality rate within 28 days among patients moderately severe acute pancreatitis (MSAP) and severe acute pancreatitis (SAP).

Methods: In this randomized, placebo-controlled trial, patients diagnosed with predicted MSAP or SAP within 72 h of symptom onset were enrolled to receive either a vitamin C infusion (200 mg/kg/24 h) or a matched placebo for 7 days. The primary outcome was 28-day mortality.

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We report a novel cobalt-catalyzed intramolecular 1,4-hydrofunctionalization of dienes. The reaction proceeds under mild conditions and is amenable to N- and O-nucleophiles. The protocol exhibits exclusive regioselectivity, yielding a number of different alkenyl heterocycles, including but not limited to dihydroisobenzofurans, isochromanes, tetrahydrofurans, morpholines, lactones, and isoindolines.

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Treatment of alkyl α-(-heteroaryl)-α-diazoacetates with alkylating reagents affords diazoacetate N-heteroarenium salts. These novel 'onium' diazo compounds are mostly yellow solids, displaying increased thermal and acid stability. Their tetrafluoroborates undergo rhodium catalyzed [2 + 1] and Doyle-Kirmse reactions under mild conditions, suggesting the -quaternization an effective means of elimination of -coordination caused catalyst toxicity.

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A palladium-catalyzed spirocyclopropanation of -difluoroalkenes with π-allylpalladium 1,4-dipoles has been successfully developed, which gives a powerful and straightforward synthetic strategy for the construction of novel -difluorinated spirocyclic compounds, 6,6-difluoro-5-oxa/azaspiro[2.4]heptanes. The scope of -difluoroalkenes can be extended to styrenes, acrylic esters, and acrylamides to realize the installment of various functional groups and different heteroatoms on the spirocyclic skeletons, which could be converted to valuable compounds with potential biological activity.

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A novel approach for the synthesis of unsaturated 7-membered lactones by Pd-catalyzed [5+2] dipolar cycloaddition of vinylethylene carbonates (VECs) and C5-substituted Meldrum's acid derivatives has been developed. Various Meldrum's acid derivatives worked well in this reaction under mild reaction conditions. A variety of 7-membered lactones can be accessed in a facile manner in moderate to good yields by employing easily prepared Meldrum's acid derivatives.

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A novel strategy for the catalytic synthesis of 2-aryl-2-benzo[][1,2,3]triazoles bearing a wide range of functional groups in good to excellent yields by non-noble molybdenum-catalyzed deoxygenative heterocyclization of 2-nitroazobenzenes is described. The salient features of the transformation include the use of readily available substrates, valuable products and ease of scale-up. The mechanistic study indicates that the reaction occurred double deoxygenation by the Mo(VI)/Mo(IV) catalytic cycle from 2-nitroazobenzene, through the formation of 2-aryl-2-benzo[][1,2,3]triazole--oxide or nitrene intermediates.

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Article Synopsis
  • Scientists found a special type of RNA called DICAR that was lower in the hearts of diabetic mice.
  • When DICAR was present, it helped protect the heart from damage caused by diabetes, but without it, the heart got worse.
  • DICAR might be important for treating heart problems in diabetes, and some lab-made versions of it showed similar helpful effects.
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Background: The timely recognition of sepsis-associated encephalopathy (SAE) remains a challenge. This study aimed to observe the CBF changes via TCD during sepsis and explore their possible predictive value in SAE.

Methods: In this prospective observational study, septic patients were enrolled and classified according to the diagnosis of SAE into two groups: SAE group and non-SAE group.

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Objective: Brain metastasis from colorectal cancer (CRC) is rare. Although stereotactic radiotherapy (SRT) and stereotactic radiosurgery (SRS) are effective treatments for brain metastasis, reports on brain metastasis of CRC are limited. This study compared the efficacy of SRT and SRS for the treatment of brain metastases from CRC and analysed the related factors to reveal the specificity CRC-derived brain metastasis.

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Tumor-triggered targeting ammonium bicarbonate (TTABC) liposomes were proposed to improve the uptake of ammonium bicarbonate (ABC) liposomes in tumor cells and retain their long circulation in our previous study. However, it must be solved how to precisely release the loaded drugs of the TTABC liposomes into tumor cells. In addition, synergistic multimodal therapy could result in better tumor treatment outcomes than monomodal chemotherapy.

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Solar-driven interfacial vaporization by localizing solar-thermal energy conversion to the air-water interface has attracted tremendous attention. In the process of converting solar energy into heat energy, photothermal materials play an essential role. Herein, a flexible solar-thermal material di-cyan substituted 5,12-dibutylquinacridone (DCN-4CQA)@Paper was developed by coating photothermal quinacridone derivatives on the cellulose paper.

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Objective: Mechanic strength, pore morphology and size are key factors for the three-dimensional (3D) printing of porous titanium scaffolds, therefore, developing optimal structure for the 3D printed titanium scaffold to fill bone defects in knee joints is instructive and important.

Methods: Structural models of titanium scaffolds with fifteen different pore unit were designed with 3D printing computer software; five different scaffold shapes were designed: imitation diamond-60°, imitation diamond-90°, imitation diamond-120°, regular tetrahedron and regular hexahedron. Each structural shape was evaluated with three pore sizes (400, 600 and 800 μm), and fifteen types of cylindrical models (size: 20 mm; height: 20 mm).

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The addition reaction of thiol to vinyl azide has been extensively studied. Variously substituted aryl thiols are all viable for this coupling process. The scope of the other partner is successfully expanded from α-aryl vinyl azide to α-alkyl vinyl azide.

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: The protective effects of 2%-4% hydrogen gas in delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) have been previously reported. This study aimed to assess the neuroprotective effects of high concentration hydrogen (HCH) on DEACMP.: A total of 36 male Sprague-Dawley rats were divided into 3 groups.

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This paper reported the health effects of mindfulness-based stress reduction (MBSR) among 49 Chinese military recruits with psychological distress in a 12-week study. Participants were randomized into a MBSR and a waitlist group. Previously validated questionnaires were administered to both groups at four time points: baseline, 5, 8, and 12 weeks after participation.

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Intramolecular imino-ene reaction of 2 H-aziridine has been studied experimentally and computationally, demonstrating that (1) the concerted process takes place regioselectively on the alkene E-CH group; (2) the geometry of the N-linker impacts the reaction activation energy and diastereoselectivity significantly, with pyramidal alkyl amine as the linkage, an exclusive cis-product is achieved; (3) when the reaction has to occur with the Z-CH group, the cis-diastereoselectivity is solely observed regardless of the nature of the N-linkage.

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A copper catalyzed intramolecular 1,2-carboboration of o-aldiminyl cinnamate has been realized in both regio- and stereoselective fashions. This reaction provides a convenient entry to highly valuable and otherwise challenging cis-2,3,4-trisubstituted tetrahydroquinolines carrying a 4-boryl group. An unusual non-Michael addition intermediate or alternatively, a cyclic enolate is proposed to account for the intriguing all-cis configuration in the final products.

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Background: Despite years of research, the treatment of acute kidney injury (AKI) remains a significant challenge. Animal studies presented causal links between elevated regulatory T cell (Treg) response and better prognosis in AKI. Previous studies in mice and humans showed that TIM-3+ Treg cells were more potent than TIM-3- Treg cells.

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A range of novel (poly)cyclic alkaloids incorporating an unprecedented 1,5-diazaspiro[2.4]heptane core that carry a spiro NH aziridine moiety and a 7-vinyl group are constructed from the thermal reaction of vinyl azides with tethered alkenes. Vinyl azides are converted to 2H-azirines in situ, which serve as enophiles for intramolecular imino-ene reactions with suitable alkenes.

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Rationale: Comamonas species are rarely associated with human infections. Recent reports found that Comamonas kerstersii was associated with severe diseases such as abdominal infection and bacteremia. However, C.

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A t-BuOCu-initiated reaction sequence of styrene borometalation and intramolecular imine addition has been achieved using a Cu(OTf)/dppf combination as catalyst. The product of this reaction cascade is a useful 2,3-disubstituted indoline bearing a versatile boryl moiety and is formed with sole cis-selectivity. To account for the observation of the exclusive formation of cis-stereoisomers, a transition state featuring copper-imine coordination is suggested.

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Cyclic ketones tethered with a vinyl azide group undergo a Schmidt-hydrolysis sequence to give secondary lactams bearing a ketone side chain. Secondary lactams are obtained in a regioselective manner that is not possible in a conventional Schimdt reaction. In addition to the well-documented C-2 nucleophilicity, the N nucleophilicity of vinyl azide disclosed in this work opens a new direction for reaction invention involving vinyl azides.

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There exist three possible patterns for the reaction of cyclic 2-oxazolidinethione and 2-benzoxazolidinethione with arynes, namely (a) S-arylation, (b) N-arylation, and (c) aryne insertion into the thiocarbonyl group (C[double bond, length as m-dash]S). Our studies demonstrate that S-arylation wins out affording S-aryl dihydrooxazoles. In contrast, for related reactions of cyclic 2-benzoxazolinone and 2-benzimidazolinone with arynes, it is found that N-arylation outcompetes O-arylation and aryne insertion into the C[double bond, length as m-dash]O group to give N-aryl 2-benzoxazolinones and N-aryl 2-benzimidazolinones.

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Background: Very few studies have explored the effects of age, time period, and cohort in association with biological, behavioral, economic, and environmental factors predictors on physical activity (PA) and sedentary behaviour (SB) among Chinese children.

Methods: We used data from a cohort study of the China Health and Nutrition Survey (CHNS) between 2004 and 2011 (2004, 2006, 2009 and 2011). The outcomes of interest were metabolic equivalent of task (MET) hours per week from both active and sedentary activities.

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