127 research outputs found
4,6-<i>O</i>-Benzylidene-Directed β-Mannopyranosylation and α-Glucopyranosylation: The 2-Deoxy-2-fluoro and 3-Deoxy-3-fluoro Series of Donors and the Importance of the O2−C2−C3−O3 Interaction
A series of 4,6-O-benzylidene-protected 2-O-benzyl-3-deoxy-3-fluoro- and 3-O-benzyl-2-deoxy-2-fluorogluco- and mannopyranosyl thioglycosides were synthesized and their coupling reactions with a
series of alcohols, on preactivation with 1-benzenesulfinylpiperidine and trifluoromethanesulfonic
anhydride, investigated. In all cases, the selectivities were lower than those observed with the corresponding
simple 4,6-O-benzylidene 2,3-di-O-benzylgluco- and mannopyranosyl thioglycosides. This leads to the
conclusion that the high β-selectivity observed with 4,6-O-benzylidene 2,3-di-O-benzylmannopyranosyl
donors under the same conditions is in large part derived from the compression of the O2−C2−C3−O3
torsion angle on going from the intermediate covalent glycosyl triflate to the oxacarbenium ion, as
compared to the relaxation of this torsion angle in the gluco series
Stereocontrolled Synthesis of d- and l-β-Rhamnopyranosides with 4-<i>O</i>-6-<i>S</i>-α-Cyanobenzylidene-Protected 6-Thiorhamnopyranosyl Thioglycosides
The synthesis of both enantiomers of a 4-O-6-S-α-cyanobenzylidene-protected 6-thiorhamnopyranosyl thioglycoside is described starting from d-mannnose and l-arabinose derivatives for the d- and l-series, respectively. This donor is effective in the preparation of the corresponding β-glycosides using the 1-benzenesulfinyl piperidine/trifluoromethanesulfonic anhydride protocol. Following desulfurization and concomitant debenzylation with Raney nickel, the so-formed 6-thio-β-mannosides are converted in high yield to the β-rhamnopyranosides
The 4-(<i>tert</i>-Butyldiphenylsiloxy)-3-fluorobenzyl Group: A New Alcohol Protecting Group, Fully Orthogonal with the <i>p</i>-Methoxybenzyl Group and Removable under Desilylation Conditions
A new benzyl ether-type protecting group for alcohols, the 4-(tert-butyldiphenylsiloxy)-3-fluorobenzyl group, is introduced. The protecting group is introduced by means of the readily prepared benzyl bromide and is cleaved with tetrabutylammonium fluoride in dimethylformamide under microwave irradiation. The fluoride substituent provides stability to oxidizing conditions, such that the new protecting group is fully compatible with the removal of p-methoxybenzyl ethers with DDQ. Applications of the new protecting group in the direct stereocontrolled synthesis of β-mannopyranosides are presented
DataSheet1_Efficacy and safety of total glucosides of paeony as an add-on treatment in adolesents and adults with chronic urticaria: A systematic review and meta-analysis.PDF
Background: Total glycosides of paeony (TGP), an active compound extracted from the dried roots of Paenoia lactiflora Pall., has been widely used to treat chronic urticaria (CU) in China. This study aims to systematically evaluate the efficacy and safety of TGP as an add-on treatment for the treatment of CU in adolescents and adults.Methods: Eight literature databases and two clinical trial registries were searched from their inception to 31 May 2022. Randomized controlled trials on TGP as an add-on treatment for CU in adolescents and adults were included. The Cochrane Collaboration’s risk of bias tool was used for the methodological quality assessment, and RevMan 5.3 software and Stata 12.0 software were used for data analyses.Results: A total of 30 studies with 2,973 participants were included in this meta-analysis. The methodological qualities of all included studies were suboptimal. The pooled results showed that TGP combined with H1-antihistamine was superior to H1-antihistamine alone in the cure rate (risk ratio (RR) = 1.54, 95% confidence interval (CI) = 1.39 to 1.71, p Conclusions: TGP as an add-on treatment could provide a good effect for CU in adolescents and adults with mild and tolerable adverse events. However, in view of poor methodological quality, high-quality and long-term clinical trials are needed in the future to confirm and update the evidence.</p
Data_Sheet_1_Efficacy and Safety of Mucopolysaccharide Polysulfate Cream for Non-Exudative Eczema: A Systematic Review and Meta-Analysis.PDF
Background: Mucopolysaccharide polysulfate (MPS) cream as a moisturizer is widely applied to treat eczema, and a lot of clinical trials have demonstrated its efficacy and safety. However, there is no further research to collect and analyze these studies.Objective: This meta-analysis aimed to assess the efficacy and safety of MPS cream as monotherapy or add-on therapy for non-exudative eczema.Methods: Ten databases were searched to identify the eligible randomized controlled trials (RCTs) from their inception to July 31, 2021. Revman 5.3 software was used for the meta-analysis.Results: A total of eligible 20 studies were included. Among the 20 studies, 2 studies compared MPS cream with other moisturizers, 14 compared MPS cream plus topical corticosteroids (TCS) with TCS alone, and 4 compared with MPS cream plus tacrolimus ointment with tacrolimus ointment alone. The pooled results demonstrated that MPS cream had a higher total efficacy rate [Risk ratio (RR) 1.21, 95% CI: 1.12 to 1.30, P Conclusions: MPS cream as monotherapy or add-on therapy could provide a good effect for treating non-exudative eczema with mild and tolerable skin adverse events. However, due to the suboptimal quality of the included studies, high-quality and large-sample RCTs are needed in the future for update or validation.Systematic Review Registration: PROSPERO (https://www.crd.york.ac.uk/PROSPERO/), identifier: CRD42021265735.</p
Distribution of feature and control points, with feature points in blue and calculated control points in red.
Distribution of feature and control points, with feature points in blue and calculated control points in red.</p
Private key security management scheme.
The fundamental technology behind bitcoin, known as blockchain, has been studied and used in a variety of industries especially in finance. The security of blockchain is extremely important as it will affects the assets of the clients as well as it is the lifeline feature of the entire system that needs to be guaranteed. Currently, there is a lack of a methodical approach to guarantee the security and dependability of the private key during its whole life. Furthermore, there is no quick, easy, or secure way to create the encryption key. A biometric-based private key encryption and management framework (BPKEM) for blockchain is proposed not only to solve the private key lifecycle manag- ement problem, but also it maintains compatibility with existing blockchain systems. For the problem of private key encryption, a biometric-based stable key generation method is proposed. By using the relative invariance between facial and fingerprint feature points, this measure can convert feature points into stable and distinguishable descriptors, then using a reusable fuzzy extractor to create a stable key. The correct- ness and efficiency of the newly proposed biometric-based blockchain encryption tech- nique in this paper has been validated in the experiments.</div
Association of TLR2 and TLR9 gene polymorphisms with atopic dermatitis: a systematic review and meta-analysis with trial sequential analysis
Atopic dermatitis (AD) is a chronic, inflammatory skin disease. The mechanism was complex. Genetic mutations of Toll-like receptor (TLR) may be associated with AD, yet still unclear. We aim to provide specific evidence of the association of TLR2, TLR9 gene polymorphisms with AD. Publications were selected according to the criteria. Newcastle-Ottawa Scale was applied to evaluate the quality. The value of ORs and 95%CIs were applied to measure the associations. According to the heterogeneity, the effects model of fixed or random was selected in data combination. For TLR2 gene rs5743708 polymorphism, under allele and recessive contrasts, the pooled data showed a significant correlation, which was A vs a, OR = 0.51 (95%CI: 0.30, 0.86); AA vs Aa + aa, OR = 0.54 (95%CI: 0.33, 0.88). For TLR2 gene rs4696480 polymorphism, under allele, homozygous, heterozygous, and dominant contrasts, the pooled data showed a significant correlation, which was A vs a, OR = 0.79 (95%CI: 0.64, 0.97), AA vs aa, OR = 0.65 (95%CI: 0.43, 0.97), Aa vs aa, OR = 0.68 (95%CI: 0.48, 0.97), AA + Aa vs aa, OR = 0.67 (95%CI: 0.49, 0.93). There are significant associations of TLR2 gene rs5743708, rs4696480 polymorphisms with atopic dermatitis, while no associations are found in TLR9 gene rs5743836, rs187084 polymorphisms.</p
Hamming distance of the descriptor between four sets of experimental data.
Hamming distance of the descriptor between four sets of experimental data.</p
Face image extracted based on HOG algorithm.
The fundamental technology behind bitcoin, known as blockchain, has been studied and used in a variety of industries especially in finance. The security of blockchain is extremely important as it will affects the assets of the clients as well as it is the lifeline feature of the entire system that needs to be guaranteed. Currently, there is a lack of a methodical approach to guarantee the security and dependability of the private key during its whole life. Furthermore, there is no quick, easy, or secure way to create the encryption key. A biometric-based private key encryption and management framework (BPKEM) for blockchain is proposed not only to solve the private key lifecycle manag- ement problem, but also it maintains compatibility with existing blockchain systems. For the problem of private key encryption, a biometric-based stable key generation method is proposed. By using the relative invariance between facial and fingerprint feature points, this measure can convert feature points into stable and distinguishable descriptors, then using a reusable fuzzy extractor to create a stable key. The correct- ness and efficiency of the newly proposed biometric-based blockchain encryption tech- nique in this paper has been validated in the experiments.</div
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