To study the relationship between the number of hydroxyl groups of polyols and the plasticizing effect, the effects of different polyols including ethylene glycol, glycerol, erythritol, xylitol and ...sorbitol on the structure and properties of corn starch straws were analyzed and compared. The results showed that the addition of plasticizer significantly improved the performance of starch straws, which greatly improved the mechanical properties, water absorption rate (WAR) and thermal stability. However, there was no linear relationship between the plasticizing effect on starch straws and the number of hydroxyl groups in plasticizers. Fourier transform infrared (FTIR) results showed that erythritol formed the strongest intermolecular interaction with starch. Starch straws with erythritol (S-ERY) had the highest bending force (Fb = 25.78 N) and the lowest WAR. Starch straws with glycerol (S-GLY) showed the lowest relative crystallinity (RC = 12.87 %) and the highest temperature of the maximum degradation (Tdmax = 302.1 °C). In addition, after storing for 180 days, S-GLY showed higher modulus of elasticity in bending (Eb = 4.26 N/cm) and a uniform surface.
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The aim of our study was to evaluate the effect of tear and repair of the lateral meniscal posterior root (LMPR) on the patellofemoral contact pressure of the knee after anterior cruciate ligament ...(ACL) reconstructed.
This was a descriptive study. Six fresh-frozen cadaveric knees collected by The Third Hospital of Hebei Medical University from January 2019 and January 2022 were placed on a customized testing rig. Patellofemoral contact pressures were measured at 30°, 60°, and 90° of flexion using pressure-sensitive film inserted between the patella and trochlea. The following knee states were tested: ACL reconstruction and intact lateral meniscus, ACL reconstruction, and LMPR tear, and ACL reconstruction and LMPR repair. Pressure measurements were recorded for each state.
In the ACL-reconstructed knee, a tear of the LMPR increased patellofemoral contact pressure at 30° of knee flexion. The repair of the posterior root by transosseous pull-out suture reduced the patellofemoral contact pressure as the status of intact lateral meniscal posterior root at 30° of knee flexion. There was no statistical difference between ACL reconstruction with the intact meniscal root and with the meniscal root tear and with the meniscal root repair at 60° and 90° of knee flexion.
The posterior root tear and repair of the lateral meniscus could have an influence on patellofemoral contact stress of the knee after ACL reconstruction at 30° of knee flexion.
Abstract Background No formal systematic review or meta-analysis was performed up to now to summarize the risk factors of dislocation after revision total hip arthroplasty(THA). Aims The present ...study aimed to quantitatively and comprehensively conclude the risk factors of dislocation after revision total hip arthroplasty. Methods A search was applied to CNKI, Embase, Medline, and Cochrane central database (all up to October 2016). All studies assessing the risk factors of dislocation after revision THA without language restriction were reviewed, and qualities of included studies were assessed using the Newcastle–Ottawa Scale. Data were pooled and a meta-analysis completed. Results A total of 8 studies were selected, which altogether included 4656 revision THAs. 421 of them were cases of dislocation occurred after surgery, suggesting the accumulated incidence of 9.04%. Results of meta-analyses showed that age at surgery (standardized mean difference −0.222; 95% CI -0.413–0.031), small-diameter femoral heads (≤28 mm) (OR 1.451; 95%CI 1.056–1.994), history of instability (OR 2.739; 95%CI 1.888–3.974), number of prior revisions ≥ 3 (OR, 2.226; 95% CI, 1.569–3.16) and number of prior revisions ≥ 2 (OR 1.949; 95% CI 1.349–2.817), acetabular components with elevated rim liner were less likely to develop dislocation after revision THA (OR 0.611; 95% CI 0.415–0.898). Conclusions Related prophylaxis strategies should be implemented in patients involved with above-mentioned risk factors to prevent dislocation after revision THA.
The myrosinase cleavage of glucosinolates yields thioglycosidic compounds that show cancer chemoprevention. Glucosinolates occupied about 5% of the oil-pressed residue of rapeseeds. The present study ...describes the separation of 3-butenyl-glucosinolate (
G1) and 2-hydroxy-3-butenyl-glucosinolate (
G2) from the extract of the oil-pressed residue of rapeseeds by using slow rotary countercurrent chromatography (SRCCC) with a solvent system composed of
n-butanol–acetonitrile–10% (NH
4)
2SO
4 water solution (1:0.5:2, v/v/v). The separation of 50
g crude extract by a SRCCC instrument equipped with a 22
L column yielded 0.91
g of
1 and 3.57
g of
2 in 37.5
h. The purity of the two compounds was more than 95%, determined by HPLC. The structures of compounds
1 and
2 were identified by ESI-MS,
1H NMR and
13C NMR.
Although many surgical or non-operative therapies have been developed to treat Achilles tendon injuries, the prognosis of which is often unsatisfactory. Recently, biologic approaches using ...multipotent stem cells like tendon-derived stem cells (TDSCs) pose a possible treatment option. To evaluate whether the Leucine rich repeat containing 32 (Lrrc32) affects the tenogenic differentiation of TDSCs and thus promotes Achilles tendon healing. TDSCs were infected with the recombinant Lrrc32-overexpressing lentivirus (LV-Lrrc32) and then locally injected into the injured site of rat. Four weeks after surgery, the Achilles tendon tissue (~0.5 cm) around the injured area was harvested for analysis. Pathological results showed that Lrrc32-overexpressing TDSCs significantly improved the morphological changes of the injured tendons. Specifically, the increased collagen-I expression and hydroxyproline content in extracellular matrix, and more orderly arrangement of the regenerated collagen fibers were observed in the Lrrc32 overexpression group. Moreover, 4 weeks after injection of Lrrc32-overexpressing TDSCs, the expression of tenocyte-related genes such as tenomodulin (Tnmd), scleraxis (Scx) and decorin (Dcn) were upregulated in the area of the healing tendon. These findings indicated that Lrrc32 promoted the tenogenic differentiation of TDSCs in vivo. Additionally, Lrrc32 overexpression also increased the expression of TGF-β1 and p-SMAD2/3, suggesting that the beneficial effects of Lrrc32 on tendon repair might be associated with the expression of TGF-β1 and p-SMAD2/3. Our findings collectively revealed that Lrrc32-overexpressed TDSCs promoted tendon healing more effectively than TDSCs alone.
Slow rotary countercurrent chromatography (SRCCC) was used for the separation of saponins from towel gourd crude extract (Luffa cyclindria Roem.) with a biphasic solvent system composed of ...chloroform-methanol-water (13:7:8, v/v). In each separation of SRCCC, 3 g crude saponins sample yielded 357 mg Lucyoside Q (1) and 213 mg Lucyoside H (2). The structures of the two compounds were confirmed by means of ESI-MS,
1
H- and
13
C-NMR.
Ramelteon is the first medicine in human history that treat insomnia as a melatonin receptor agonist. Herein, we report an efficient three‐step synthetic route to access it from commercially ...available 2,3‐dihydrobenzofuran‐4‐amine, which represents as the shortest racemic synthesis to date with a 26 % overall yield. Key to the success is the application of the intermolecular Catellani‐type alkylation and intramolecular redox‐relay Heck cyclization cascade for preparation of the key indane‐containing aldehyde. The unique primary amide‐involved reductive amination of aldehyde is another feature of this route. New process of ramelteon can be developed based on this chemistry.
Taking the shorter path: An efficient three‐step synthetic route to access the anti‐insomnia medicine ramelteon from commercially available 2,3‐dihydrobenzofuran‐4‐amine was developed, which represents as the shortest racemic synthesis to date.
The objective is to explore optimal method to induce conotruncal cardiac defects with all-trans retinoic acid, providing the basis for establishment of transgene animal model. Conclusions All-trans ...retinoic acid may induce conotruncal cardiac defects in C57BL/6J mice embryos and concentration gradient has effect on conotruncal defective phenotype.
N6-(2-deoxy-α,β-d-erythro-pentofuranosyl)-2,6-diamino-4-hydroxy-5-formamido-pyrimidine (Fapy•dG) is formed from a common intermediate and in comparable amounts to the well-studied mutagenic DNA ...lesion 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OxodGuo). Fapy•dG preferentially gives rise to G → T transversions and G → A transitions. However, the molecular basis by which Fapy•dG is processed by DNA polymerases during this mutagenic process remains poorly understood. To address this we investigated how DNA polymerase β (Pol β), a model mammalian polymerase, bypasses a templating Fapy•dG, inserts Fapy•dGTP, and extends from Fapy•dG at the primer terminus. When Fapy•dG is present in the template, Pol β incorporates TMP less efficiently than either dCMP or dAMP. Kinetic analysis revealed that Fapy•dGTP is a poor substrate but is incorporated ∼3-times more efficiently opposite dA than dC. Extension from Fapy•dG at the 3'-terminus of a nascent primer is inefficient due to the primer terminus being poorly positioned for catalysis. Together these data indicate that mutagenic bypass of Fapy•dG is likely to be the source of the mutagenic effects of the lesion and not Fapy•dGTP. These experiments increase our understanding of the promutagenic effects of Fapy•dG.
Modified nucleotides often hinder and/or decrease the fidelity of DNA polymerases. Tandem lesions, which are comprised of DNA modifications at two contiguous nucleotide positions, can be even more ...detrimental to genome stability. Recently, tandem lesions containing 5-formyl-2’-deoxyuridine (5fdU) flanked at the 5’-position by 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-OxodGuo) or N-(2-deoxy-α,β-D-erythropentofuranosyl)-N-(2,6-diamino-4-hydroxy-5-formamidopyrimidine (Fapy•dG) were discovered. We examined the replication of 5’− 8-OxodGuo-5fdU and 5’-Fapy•dG-5fdU tandem lesions in HEK 293T cells and several polymerase deficient variants by transfecting single-stranded vectors containing them. The local sequence of the tandem lesions encompasses the 273 codon of the p53 gene, a mutational hot-spot. The bypass efficiency and mutation spectra of the tandem lesions were compared to those of the isolated lesions. Replication of weakly mutagenic 5-fdU is little changed when part of the 5’− 8-OxodGuo-5fdU tandem lesion. G → T transversions attributable to 8-OxodGuo increase > 10-fold when the tandem lesion is bypassed. 5’-Fapy•dG-5fdU has a synergistic effect on the error-prone bypass of both lesions. The mutation frequency (MF) of 5’-Fapy•dG-5fdU increases 3-fold compared to isolated Fapy•dG. In addition, a 5’-adjacent Fapy•dG significantly increases the MF of 5fdU. The major mutation, G → T transversions, decrease by almost a third in hPol κ- cells, which is the opposite effect when isolated Fapy•dG in the same sequence context is replicated in HEK 293T cells in the same sequence. Steady-state kinetics indicate that hPol κ contributes to greater G → T transversions by decreasing the specificity constant for dCTP compared to an isolated Fapy•dG. The greater conformational freedom of Fapy•dG compared to 8-OxodGuo and its unusual ability to epimerize at the anomeric center is believed to be the source of the complex effects of 5’-Fapy•dG-5fdU on replication.
•G → T transversions increase >10-fold upon replication of 5’-8-OxodGuo-5fdU tandem lesion relative to 8-OxodGuo.•Mutation frequency of tandem 5’-Fapy•dG-5fdU is 3-fold greater in compared to isolated Fapy•dG.•5’-Fapy•dG-5fdU gave a more complex mutational pattern than 5’−8-OxodGuo-5fdU tandem lesion.•5fdU is much more mutagenic when it is part of a 5’-Fapy•dG-5fdU tandem lesion.
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