Al-Li alloy is widely used in aircraft manufacturing due to its high specific strength. The micro-strengthening mechanisms have been investigated widely, including precipitate and solute ...strengthening. However, the influence of crystallographic texture on mechanical properties remains unclear, because current researches are based on rolled sheet. In this paper, 2198 Al-Li alloy bars were processed using hot extrusion to obtain a texture different from rolling. The mechanical properties were tested via uniaxial tension. The microstructure was observed using scanning electron microscopy, electron backscattered diffraction, and transmission electron microscopy. The results show that the yielding strength and ultimate tensile strength (UTS) of extruded 2198 Al-Li alloy bars are greatly improved due to the precipitation of
T
1
precipitate after artificial aging. With the increasing of pre-deformation, the number of
T
1
increases, and the size of
T
1
precipitate is close to each other, leading to a remarkable increase in strength. When the pre-deformation is 6%, the UTS reaches 611 MPa. 2198 Al-Li alloy bars possess two types of fiber textures: // extrusion direction and // extrusion direction. The presence of fibrous texture with a low Schmid factor can increase the strength of extruded 2198 Al-Li alloy bars. The fracture mechanism of the bar is ductile fracture after artificial aging, while the fracture mechanism is a mix of micropore aggregation and cleavage after natural aging.
Lemonomycin (1) was first isolated from the fermentation broth of Streptomyces candidus in 1964. The complete chemical structure was not elucidated until 2000 with extensive spectroscopic analysis. ...Lemonomycin is currently known as the only glycosylated tetrahydroisoquinoline antibiotic. Its potent antibacterial activity against Staphylococcus aureus and Bacillus subtilis and complex architecture make it an ideal target for total synthesis. In this short review, we summarize the research status of lemonomycin for biological activity, biosynthesis, and chemical synthesis. The unique deoxy aminosugar-lemonose was proposed to play a crucial role in biological activity, as shown in other antibiotics, such as arimetamycin A, nocathiacin I, glycothiohexide α, and thiazamycins. Given the self-resistance of the original bacterial host, the integration of biosynthesis and chemical synthesis to pursue efficient synthesis and further derivatization is in high demand for the development of novel antibiotics to combat antibiotic-resistant infections.
Abstract
Background
A giant cell tumor (GCT) is a benign neoplasm characterized by mixture of mononuclear cells and multinucleated cells. A GCT of soft tissue (GCT-ST) is developed in various ...extraosseous sites, but GCT-ST of the gastrointestinal tract is very rare. GCT-ST usually has a benign course, but rare cases reported malignant potential of the tumor. Therefore, complete resection is required to prevent local recurrence or distant metastasis.
Case presentation
A 53-year-old woman was admitted for follow-up colonoscopy who underwent the colorectal endoscopic submucosal dissection (ESD) of a laterally spreading tumor at the hepatic flexure 6 months ago. A colonoscopy showed a polypoid mass about 3.5 × 2.5 cm at the previous ESD site. As endoscopic finding showed a smooth multi-nodular tumor without submucosal invasion, we performed endoscopic mucosal resection. Based on pathological and immunohistochemical findings, the lesion was diagnosed as a GCT-ST in the colon. Follow-up colonoscopy performed 6 months later revealed no evidence of recurrence.
Conclusion
This is the first report of a GCT-ST identified in the colon. Although GCT-ST generally has a benign clinical course, complete resection should be performed to prevent local recurrence and metastasis.
According to the pharmacophore binding strategy and principle of bioelectronic isobaric, used the sulfonylurea bridge as the parent structure, a series of novel thiourea compounds containing ...aromatic-substituted pyrimidines were designed and synthesized. The preliminary herbicidal activity tests showed that some compounds had good herbicidal activity against Digitaria adscendens, Amaranthus retroflexus, especially for compound 4d and 4f. The results showed that compound 4d had an inhibition rate of 81.5% on the root growth of Brassica napus L. at the concentration of 100 mg L−1, and compound 4f had an inhibition rate of 81% on the root growth of Digitaria adscendens at the concentration of 100 mg L−1. Compounds 4d and 4f had higher comparative activity on Echinochloa crus-galli than the commercial herbicide bensulfuron-methyl. The preliminary structure-activity relationship (SAR) was also summarized. We also tested the in vivo AHAS enzyme activity inhibition experiment of 14 compounds at 100 mg L−1, and the results showed that they all have inhibitory activity on the enzyme, with the highest inhibition rate reaching 44.4% (compound 4d). Based on the results of molecular docking to yeast acetohydroxyacid synthase (AHAS), the possible herbicidal activity mechanism of these compounds was evaluated.
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•Synthesis of thiourea derivatives•Herbicidal activity of thiourea derivatives•The inhibitory activity of thiourea derivatives on AHAS enzyme•Molecular docking of thiourea derivatives and AHAS enzyme
Infection associated with biomedical implants remains the main cause of failure, leading to reoperation after orthopedic surgery. Orthopedic infections are characterized by microbial biofilm ...formation on the implant surface, which makes it challenging to diagnose and treat. One potential method to prevent and treat such complications is to deliver a sufficient dose of antibiotics at the onset of infection. This strategy can be realized by coating the implant with thermoregulatory polymers and triggering the release of antibiotics during the acute phase of infection. We developed a multi-layered temperature-responsive polymer brush (MLTRPB) coating that can release antibiotics once the temperature reaches a lower critical solution temperature (LCST). The coating system was developed using copolymers composed of diethylene glycol methyl ether methacrylate and 2-hydroxyethyl methacrylate by alternatively fabricating monomers layer by layer on the titanium surface. LCST was set to the temperature of 38-40 °C, a local temperature that can be reached during infection. The antibiotic elution characteristics were investigated, and the antimicrobial efficacy was tested against
(Xen29 ATCC 29 213) using one to four layers of MLTRPB. Both in vitro and in vivo assessments demonstrated preventive effects when more than four layers of the coating were applied, ensuring promising antibacterial effects of the MLTRPB coating.
Flow electrodes have recently been studied for use in capacitive deionization applications because of their continuous and high desalting efficiency. The production capacity of desalinated water in ...the flow-electrode capacitive deionization (FCDI) system is limited compared to infinite ion capacity of the flow electrodes due to restrictions in the flow rate of the influent/effluent. Therefore, we designed and fabricated an FCDI stack with five unit cells in order to increase the production capacity of desalinated water. Through inlet pressure measurements of the flow electrodes in the FCDI stack, we confirmed that the flow electrodes were uniformly segmented from the manifold formed in the FCDI stack into the flow channels of each unit cell. We also confirmed that there was no pressure increase at the flow electrode in the flow channel caused by an increase in the number of unit cells in the FCDI stack. Also, the FCDI stack showed a similar desalting efficiency when compared to that of the FCDI unit cell. On the basis of the results, we verified that the FCDI stack can be successfully used to scale up the desalinated water production capacity of the FCDI system.
Laparoscopic common bile duct exploration (LCBDE) is one of the minimally invasive options for choledocholithiasis. Primary closure of the common bile duct (CBD) upon completion of laparoscopic ...choledochotomy is safe in selected patients. The present study aimed to evaluate the feasibility and safety of primary closure of CBD after LCBDE in patients aged 70 years or older.
A total of 116 patients (51 males and 65 females) who suffered from choledocholithiasis and underwent primary closure of the CBD (without T-tube drainage) after LCBDE from January 2003 to December 2017 were recruited. They were classified into two groups according to age: group A (≥70 years, n = 56), and group B (<70 years, n = 60). The preoperative characteristics, intraoperative details, and postoperative outcomes of the two groups were evaluated.
The mean operative time was 172.02 min for group A and 169.92 min for group B (P = 0.853). The mean hospital stay was 7.40 days for group A and 5.38 days for group B (P < 0.001). Bile leakage occurred in two patients in group A and one in group B (3.57% vs 1.67%, P = 0.952). There were no significant differences in the rates of postoperative complications and mortality between the two groups. At median follow-up time of 60 months, stone recurrence was detected in one patient in group A and two in group B (1.79% vs 3.33%, P = 1.000). Stenosis of CBD was not observed in group A and slight stenosis in one patient in group B (0 vs 1.67%, P = 1.000).
Primary closure of the CBD upon completion of laparoscopic choledochotomy is safe and feasible in elderly patients ≥70 years old.
Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease with no cure. Bufotalin (BT), an active component extracted from Venenum Bufonis, has been prescribed as a treatment for ...chronic inflammatory diseases. However, whether BT has antifibrotic properties has never been investigated. In this study, we report on the potential therapeutic effect and mechanism of BT on IPF. BT was shown to attenuate lung injury, inflammation, and fibrosis as well as preserve pulmonary function in bleomycin (BLM)-induced pulmonary fibrosis model. We next confirmed BT's ability to inhibit TGF-β1-induced epithelial-mesenchymal transition (EMT) and myofibroblast activation (including differentiation, proliferation, migration, and extracellular matrix production) in vitro. Furthermore, transcriptional profile analysis indicated the Wnt signaling pathway as a potential target of BT. Mechanistically, BT effectively prevented β-catenin from translocating into the nucleus to activate transcription of profibrotic genes. This was achieved by blunting TGF-β1-induced increases in phosphorylated Akt Ser437 (p-Akt S437) and phosphorylated glycogen synthase kinase (GSK)-3β Ser9 (p-GSK-3β S9), thereby reactivating GSK-3β. Additionally, the antifibrotic effects of BT were further validated in another in vivo model of radiation-induced pulmonary fibrosis. Collectively, these data demonstrated the potent antifibrotic actions of BT through inhibition of Akt/GSK-3β/β-catenin axis downstream of TGF-β1. Thus, BT could be a potential option to be further explored in IPF treatment.
The purpose of this study was to investigate the effect of upper-limb robot-assisted therapy based on visual error augmentation in virtual reality (UL-RAT-VEAVR) for motor recovery and kinematics ...after chronic hemiparetic stroke. This study applied a single-group pre- and post-intervention study design. A total of 27 stroke survivors (20 males and 7 females; mean age 54.51 years, mean onset duration 12.7 months) volunteered to participate in this study. UL-RAT-VEAVR was performed three times a week for four weeks, amounting to a total of twelve sessions, in which an end-effector-based robotic arm was used with a visual display environment in virtual reality. Each subject performed a total of 480 point-to-point movements toward 3 direction targets (medial, ipsilateral, and contralateral side) in the visual display environment system while holding the handle of the end-effector-based robotic arm. The visual error (distance to the targets on the monitor) in virtual reality was increased by 5% every week based on the subject’s maximum point-to-point reaching trajectory. Upper-limb motor recovery was measured in all subjects using the Fugl−Meyer Assessment (FMA) upper-limb subscale, the Box and Block Test (BBT), and the Action Research Arm Test (ARAT), before and after training. In addition, a kinematic assessment was also performed before and after training and consisted of time, speed, distance, and curvilinear ratio for point-to-point movement. There were significant improvements in both upper-limb motor function and kinematics after 4 weeks of UL-RAT-VEAVR (p < 0.05). Our results showed that the UL-RAT-VEAVR may have the potential to be used as one of the upper-limb rehabilitation strategies in chronic stroke survivors. Future studies should investigate the clinical effects of the error-augmentation paradigm using an RCT design.
Nitroso-ene (NE) reactions have been adapted in the construction of nitrogen-containing motifs in many biologically interesting compounds. The transient and highly reactive “nitroso” species remains ...a challenge for designing stereocontrolled syntheses. Although chiral auxiliary-based method has been developed to achieve high diastereoselectivity, the use of the inherent chirality of the nitroso compound for stereochemical control remains underdeveloped. We chose the formation of a γ-lactam via a NE cyclization as a basis to study the applicable principles for future asymmetric syntheses. The selected examples presented herein reveal that the intramolecular hydrogen bond would provide conformational restraint to facilitate excellent facial selectivity in the NE reaction via a chair-like transition state. The sterically bulky amino group also provides excellent stereochemical control possibly through steric repulsion. The following transformations led to a key intermediate (Ohfune's lactone) in the preparation of manzacidins A and C and thus constitutes a formal synthesis.
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•Stereochemistry in the nitroso-ene cyclization: intramolecular hydrogen-bonding and steric hindrance effect.•Application in the stereodivergent synthesis of manzacidins A and C.•Construction of nitrogen-containing quaternary carbon center through nitroso-ene reaction.
