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991.
ContextSchisandra chinensis (Turcz.) Baill. (Magnoliaceae) essential oil (SCEO) composition is rich in lignans that are believed to perform protective effects in the liver.ObjectiveThis study investigates the effects of SCEO in the treatment of acetaminophen (APAP)-induced liver injury in mice.Materials and methodsC57BL/6 mice (n = 56) were randomly divided into seven groups: normal; APAP (300 mg/kg); APAP plus bicyclol (200 mg/kg); APAP plus SCEO (0.25, 0.5, 1, 2 g/kg). Serum biochemical parameters for liver function, inflammatory factors, and antioxidant activities were determined. The protein expression levels of Nrf2, GCLC, GCLM, HO-1, p62, and LC3 were assessed by western blotting. Nrf2, GCLC, HO-1, p62, and LC3 mRNA were detected by real-time PCR.ResultsCompared to APAP overdose, SCEO (2 g/kg) pre-treatment reduced the serum levels of AST (79.4%), ALT (84.6%), TNF-α (57.3%), and IL-6 (53.0%). In addition, SCEO (2 g/kg) markedly suppressed cytochrome P450 2E1 (CYP2E1) (15.4%) and attenuated the exhaustion of GSH (43.6%) and SOD (16.8%), and the accumulation of MDA (22.6%) in the liver, to inhibit the occurrence of oxidative stress. Moreover, hepatic tissues from our experiment revealed that SCEO pre-treatment mitigated liver injury caused by oxidative stress by increasing Nrf2, HO-1, and GCL. Additionally, SCEO activated autophagy, which upregulated hepatic LC3-II and decreased p62 in APAP overdose mice (p < 0.05).Discussion and conclusionsOur evidence demonstrated that SCEO protects hepatocytes from APAP-induced liver injury in vivo and the findings will provide a reliable theoretical basis for developing novel therapeutics.  相似文献   
992.
AimThis study aimed to synthesize qualitative evidence on experiences of patients with atrial fibrillation (AF) during the course of diagnosis and treatment. We addressed three main questions: (a) What were the experiences of patients with AF during the course of diagnosis and treatment? (b) How did they respond to and cope with the disease? (c) What were the requirements during disease management?DesignIn this study, qualitative evidence synthesis was performed using the Thomas and Harden method.Data SourcesElectronic databases, including PubMed, the Cochrane Library, Embase, Web of Science, Cumulative Index to Nursing and Allied Health Literature, the China Biomedical Database, the WanFang Database, Chinese National Knowledge Infrastructure and VIP, were searched. The databases were searched from inception to August 2021.Review MethodsTwo researchers independently selected studies using qualitative assessment and review instruments for quality evaluation and thematic synthesis for the data analysis.ResultsA total of 2627 studies were identified in the initial search and 15 studies were included. Five analytical themes were generated: ‘Diagnosing AF’; ‘The impact of AF on the patients’; ‘Self‐reorientation in the therapeutic process’; ‘Living with AF and QoL’; and ‘External support to facilitate coping strategies.’ConclusionsOur findings point out unique experiences of patients across the trajectory of AF related to delayed diagnosis, feelings of nonsupport, disappointment of repeated treatment failure and multiple distress associated with unpredictable symptoms. Future research and clinical practice are expected to improve the quality of medical diagnosis and treatment, optimize administrative strategy and provide diverse health support for patients with AF.ImpactUnderstanding the experiences and needs of patients with AF in the entire disease process will inform future clinical practice in AF integrated management, which would be helpful in improving the professionalism and confidence of healthcare providers. In addition, our findings have implications for improving the effectiveness of AF diagnostic and treatment services.Patient or Public ContributionThis paper presents a review of previous studies and did not involve patients or the public.  相似文献   
993.
A series of cinchona alkaloid-based NNP ligands, including a new one, have been employed for the asymmetric hydrogenation of ketones. By combining ruthenium complexes, various aromatic and heteroaromatic ketones were smoothly reacted, yielding valuable chiral alcohols with extremely high 99.9% ee. Moreover, a proposed reaction mechanism was discussed and verified by NMR.

A series of cinchona alkaloid-based NNP ligands including a new one has been employed for the asymmetric hydrogenation of ketones. By combining ruthenium complexes, various ketones were smoothly reacted with up to 99.9% ee.

Since the well-known failure of using racemic thalidomide, attention has been paid to the manufacture of optically pure compounds as effective components in pharmaceuticals and agrochemicals. Asymmetric hydrogenation of ketones, especially heteroaromatic ketones, has emerged as a popular facile route to approach enantiopure secondary alcohols as essential intermediates for the construction of biologically active molecules.1–4 Knowles et al.5 pioneered the production of enantioenriched chiral compounds in 1968, and Noyori and co-workers6–8 laid the cornerstone of asymmetric hydrogenation in 1990s. Subsequently, numerous catalytic systems have been developed. Ru-BICP-chiral diamine-KOH was developed and proved to be effective for asymmetric hydrogenation of aromatic ketones by Xumu Zhang.9 Cheng-yi Chen reported asymmetric hydrogenation of ketone using trans-RuCl2[(R)-xylbinap][(R)-daipen] and afforded secondary alcohol in 92–99% ee.10 Mark J. Burk and Antonio Zanotti-Gerosa disclosed Phanephos-ruthenium-diamine complexes catalyzing the asymmetric hydrogenation of aromatic and heteroaromatic ketones with high activity and excellent enantioselectivity.11 Qi-Lin Zhou et al. designed and synthesized chiral spiro diphosphines as a new chiral scaffold applied in the asymmetric hydrogenation of simple ketones with extremely high activity and up to 99.5% ee.12–15 Similarly, Kitamura and co-workers have developed a set of tridentate binan-Py-PPh2 ligands for the asymmetric hydrogenation of ketones affording excellent results.16 Recently, chiral diphosphines and tridentate ligands based on ferrocene have been developed for the asymmetric hydrogenation of carbonyl compound with a remarkable degree of success.17–21 Despite many ligands for asymmetric hydrogenation of ketones have been reported, expensive reagent and multistep complicated reactions were employed to synthesize most of them.22–24 In light of increasing industrial demand, easily obtained, cheap and practical chiral ligands are still highly desirable. In addition to chiral ligands, the selection of metals was essential for asymmetric hydrogenation.25–27 Although Mn,28–30 Fe,31–34 Co,35–37 Ni38,39 and Cu40,41 metals were proved to be effective for asymmetric hydrogenation in recent years, Rh,42–44 Ir45,46 and especially Ru remained the most preferred metals. Ruthenium47–51 was chosen owing to its superior performances in terms of low price, selectivity and activity. Takeshi Ohkuma,52 Hanmin Huang53,54 and Johannes G. de Vries55 all successfully used ruthenium catalysts for asymmetric hydrogenation of ketones. Admittedly, there is a continuing interest in the development of cheaper, simpler and more efficient catalysts for the asymmetric hydrogenation of ketones under mild conditions to access corresponding secondary alcohols. Recently, we developed new NNP chiral ligands derived from cinchona alkaloid for the asymmetric hydrogenation of various ketones in extremely excellent results using a iridium catalytic system.56 Prompted by these encouraging results, we were interested in exploring a ruthenium-catalyzed asymmetric hydrogenation of ketones with NNP chiral ligands derived from cinchona alkaloid. Here, we showed that changing from iridium to ruthenium, with the same simple synthetic ligands, delivered a catalyst catalyzed asymmetric hydrogenation of ketones to give the industrially important chiral alcohols with up to 99.9% ee. Although the catalytic activity of ruthenium catalyst was not as high as that of the iridium catalyst, the enantioselectivity could be maintained, and even showed higher enantioselectivity in the hydrogenation of some substrates.Chiral tridentate ligand NNP (L1–L10) were synthesized and characterized as reported in our previous publication. With tridentate ligands in hand, we began to evaluate the catalytic performance in benzylidene-bis(tricyclohexylphosphine) dichlororuthenium-catalyzed asymmetric hydrogenation of acetophenone employed as a standard substrate (Fig. 2). MeOH was found to be a better one as the conversion and enantioselectivity were 99.9% and 98.2%, respectively. Bases screening showed that Ba(OH)2 was superior to the others, giving >99.9% conversion and 98.8% ee in the present catalytic system (Fig. 1). Ligand screening revealed that the configuration of chiral centers of cinchona alkaloids of the ligand markedly affected the catalytic performance. NNP ligands derived from cinchonine and quinidine appeared to benefit both the reaction rate and enantioselectivity, while those derived from cinchonidine and quinine had the opposite effect. Further, different NNP ligands that bearing different substituents on the phenyl rings were evaluated. Similar to our previous research, ligands with electron-withdonating substituents showed better catalytic performance than those with electron-withdrawing substituents. However, it was noted that the more electron-withdonating substituents furnished lower activity but same enantioselectivity. The optimal ligand L5 derived from quinidine with one methoxy group on benzene ring provided the corresponding chiral alcohol with 99.9% conversion and 98.8% ee. Considering that L3 derived from cinchonine had similar catalytic performance to L4 derived from quinidine, new ligand L10 similar to L5 with one methoxy group on benzene ring was synthesized and applied to the asymmetric hydrogenation of template substrate. 99.6% conversion and 97.6% ee was obtained. Hence, L5 was employed as better ligand in subsequent experiments.Open in a separate windowFig. 1The effect of different bases for the asymmetric hydrogenation of acetophenone (substrate/Ru/L5 = 500/1/2, ketones: 0.429 mol L−1, base: 0.15 mol L−1, MeOH: 2 mL, 30 °C, 6 MPa, 2 h.).Open in a separate windowFig. 2The effect of different solvents for the asymmetric hydrogenation of acetophenone. (substrate/Ru/L5 = 1000/1/2, ketones: 0.858 mol L−1, Ba(OH)2: 0.15 mol L−1, solvent: 2 mL, 30 °C, 6 MPa, 2 h.).The effect of different ligand for the asymmetric hydrogenation of acetophenonea
EntryLigandsCon./%ee/%Config
1L147.578.2 R
2L256.177.8 R
3L3>9994.0 S
4L480.897.0 S
5L5>9998.8 S
6L654.298.0 S
7L72.184.2 S
8L891.198.0 S
9L936.592.8 S
10L10>9997.6 S
Open in a separate windowaSubstrate/Ru/L = 2000/1/2, ketones: 1.715 mol L−1, Ba(OH)2: 0.15 mol L−1, MeOH: 2 mL, 30 °C, 6 MPa, 2 h.In order to evaluate the general applicability of this method, we have surveyed the substrate scope. As can be discerned from the data in Fig. 3, most of aryl alkyl ketones P1–P21 were hydrogenated with very high enantioselectivities (97.1–99.9% ee). Under the conditions employed, the electron effect and steric hindrance seemed to have no significant impact on the enantioselectivities of asymmetric hydrogenation. However, the activities were slightly affected by steric hindrance, especially ortho-substituted group. Significantly, Ru/L5 showed high enantioselectivity 98.2% in the hydrogenation of [3,5-bis(trifluoromethyl)phenyl]ethanone and its corresponding enantiopure alcohol P21 was key chiral intermediates for the NK-1 receptor antagonist aprepitant.57,58 Additionally, chiral heteroaromatic alcohols containing nitrogen, oxygen or sulfur in the heterocyclic ring were considerable organic synthetic intermediate in pharmaceuticals and organic synthesis.59–61 Nevertheless, due to the coordination ability of the heteroaromatic moiety, the asymmetric hydrogenation of heteroaromatic ketones has been less investigated. Surprisingly, the protocol was found to be very effective for asymmetric hydrogenation of various heteroaromatic ketones P22–P35. The substrates were all well reduced smoothly to afford the corresponding chiral alcohol with 97.1–99.9% ee. Notably, meta- and para-acetyl pyridines, generally as a challenging hydrogenation substrates62–64 owe to stronger coordination ability, were also hydrogenated with up to 97.2% ee (P33 and P34). Gratifyingly, 97.4 ee was obtained when acetonaphthone employed (P36). Benzo-fused seven-membered cyclic ketone proceeded well to afford the corresponding chiral alcohols with 99.6% ee (P37). To further explore substrate scope, we checked the effectiveness of method for asymmetric hydrogenation of unsaturated ketones. Although, both substrates were hydrogenated with high yield, only medium enantioselectivity 73.8 and 78.3% ee were given, respectively.Open in a separate windowFig. 3Asymmetric hydrogenation of ketones catalyzed by Ru/L5. (Substrate/Ru/L5 = 200/1/2, ketones: 0.171 mol L−1, Ba(OH)2: 0.15 mol L−1, MeOH: 2 mL, 30 °C, 6 MPa, 2 h, isolated yield, ee was determined by GC or HPLC on chiral stationary phase (see the ESI); asubstrate/Ru/L5 = 2000/1/2; bsubstrate/Ru/L5 = 100/1/2, 25 °C; csubstrate/Ru/L5 = 50/1/2, 25 °C, 24 h; dsubstrate/Ru/L5 = 25 °C; esubstrate/Ru/L5 = 50/1/2, 4 h; fEtOH).To understand the mechanism of the reaction, NMR was introduced to investigated active species. Single peak at δ = 19.91 ppm belonging to phenyl vinyl group of the complex disappeared in the 1H NMR spectrum when the complex was mixed with the ligand (Fig. S1, ESI). In the meantime, 31P NMR spectrum of the mixture exhibited new singlet at δ = 55.71 ppm (s) with the signal of complex disappearing (Fig. S2, ESI). These maybe indicated the formation of ruthenium complex A. Subsequently, a new weak signal was generated in the 31P NMR spectrum with the introduction of hydrogen and base (Fig. S3, ESI). These may indicate the formation of ruthenium hydride complexes. Meanwhile, the 1H NMR spectrum exhibited several weak signals below 0 ppm (Fig. S4, ESI). These data also verified the formation of ruthenium hydride complexes. Reference to relevant literature,65–67 the proposed catalytic cycle for the asymmetric hydrogenation of ketones with the ruthenium complex was shown in Scheme 1. First, the ruthenium complex reacted with ligands to form complex A. In the presence of base and hydrogen, the complex A lost two chlorine atoms to transform into dihydride complex B. Then, a hydridic Ru–H and a protic N–H unit were transferred from dihydride B to the carbonyl group of the ketones through the transition state TS to produce chiral alcohol. And the ruthenium complex lost two hydrogen atoms to form complex C. Finally, dihydride B was regenerated in hydrogen atmosphere. Compared with the reported iridium catalytic system with the same chiral ligands, the hydrogenation activity of the ruthenium catalytic system decreased significantly although maintained high enantioselectivity. The result indicates that the selection of metals was as important as chiral ligands for asymmetric hydrogenation.Open in a separate windowScheme 1Proposed mechanism for the asymmetric hydrogenation.  相似文献   
994.
目的:对覆盖义齿的基牙进行短期临床观察。方法:对30例覆盖义齿修复患者半年及1年后回访观察。结果:下颌基牙及非银汞充填覆盖基牙更易存积菌斑及结石,并出现牙龈问题。结论:对于能保持良好口腔卫生的患者,覆盖义齿是一种较好的选择。  相似文献   
995.
Although localized prostate cancer(PCa)can be cured by prostatectomy and radiotherapy,the development of effective therapeutic approaches for advanced prostate ...  相似文献   
996.
997.
5-Hydroxymethylfurfural (HMF) is a valuable platform chemical derived from biomass and lots of research focuses on the synthesis of HMF from fructose and glucose. Herein, conversion of bio-carbohydrates to 5-hydroxymethylfurfural (HMF) was studied in the three-component deep eutectic solvent (DES) system, which was composed of choline chloride (ChCl), boric acid and substrates such as fructose, glucose and sucrose. Bio-carbohydrates handled under typical reaction conditions gave satisfactory conversion (44% for fructose and 31% for glucose) and yield of HMF (35% for fructose and 21% for glucose) in 1 h. Moreover, owing to the benefits of DES, the initial substrate content could be higher and the reaction temperature could be reduced, thus side reactions were effectively avoided and the selectivity of HMF was better (ranging from 79% to 100% for fructose and from 65% to 100% for glucose). We believe this method could provide a promising alternative for conversion of bio-carbohydrates to HMF and a better utilization of biomass.

The conversion process of fructose and glucose in the three-component DES system. Substrates such as fructose, glucose and sucrose treated with this DES system could convert to HMF in a satisfactory yield and selectivity.  相似文献   
998.
透明质酸是一种线性多糖,笔者对其性质、生理作用、生产方法及临床应用等方面的研究进行综述。  相似文献   
999.
朱兴  孙巍  刘波 《辽宁医学杂志》2007,21(6):375-376
近年来随着腹腔镜胆囊切除术(LC)的广泛开展,胆道损伤呈上升趋势,其发生率为0.4%~1.3%[1].如何避免胆道损伤,成功地进行胆道修复,最大限度地减轻患者的痛苦,是临床医师所面临的重要课题.我们总结了20例腹腔镜胆道损伤的临床资料,报告如下.  相似文献   
1000.
BackgroundSodium thiosulfate (STS) can be used to treat patients diagnosed with calciphylaxis, which is a rare life-threatening syndrome. However, our patients treated with the recommended STS regimen presented with serious adverse events, resulting in treatment withdrawal. Then an optimized STS regimen was used to increase the tolerance of patients to STS and improve treatment continuation. The curative effect of the new regimen is not yet definite. Therefore, this study aimed to evaluate the response to the use of the optimized STS regimen for the treatment of calciphylaxis in Chinese patients during the first three courses of treatment.MethodsDemographic, clinical, and laboratory data were retrospectively collected on 31 calciphylaxis patients with chronic kidney disease (CKD) or end-stage kidney disease (ESKD) treated with the optimized STS regimen. The primary outcome was a clinical improvement. The secondary outcomes included survival rate and adverse events.ResultsTwenty-five patients (over 80%) achieved clinical improvement considering improvement or nonspecific changes of skin lesions (80.65%) and pain relief (100%). Furthermore, 54.84% of patients did not experience any adverse events and none died from complications. During a median follow-up of 9 months (interquartile range 4‒19), 27 patients (87.10%) survived; additionally, 13 patients (41.94%) survived after a one-year follow-up period.ConclusionThe optimized STS regimen is relatively safe, associated with satisfactory outcomes, and well tolerated by patients for short to medium treatment duration. Hence, it is a promising approach for the treatment of patients diagnosed with calciphylaxis.  相似文献   
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