ABSTRACT
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
Two-dimensional materials provide extraordinary opportunities for exploring phenomena arising in atomically thin crystals. Beginning with the first isolation of graphene, mechanical exfoliation has been a key to provide high-quality two-dimensional materials, but despite improvements it is still limited in yield, lateral size and contamination. Here we introduce a contamination-free, one-step and universal Au-assisted mechanical exfoliation method and demonstrate its effectiveness by isolating 40 types of single-crystalline monolayers, including elemental two-dimensional crystals, metal-dichalcogenides, magnets and superconductors. Most of them are of millimeter-size and high-quality, as shown by transfer-free measurements of electron microscopy, photo spectroscopies and electrical transport. Large suspended two-dimensional crystals and heterojunctions were also prepared with high-yield. Enhanced adhesion between the crystals and the substrates enables such efficient exfoliation, for which we identify a gold-assisted exfoliation method that underpins a universal route for producing large-area monolayers and thus supports studies of fundamental properties and potential application of two-dimensional materials.
ABSTRACT
Rhododendron molle G. Don, belonging to the Ericaceae family, is a traditional Chinese medicinal plant with a wide spectrum of pharmacological effects. This paper aimed to review the phytochemistry, pharmacology and toxicology of R. molle, and to discuss the tendency of future investigations on this plant. A systematic review of literature about R. molle was carried out using resources including classic books about Chinese herbal medicine, and scientific data bases including CNKI, Pubmed, SciFinder, Scopus, and Web of Science. Over 67 compounds, including diterpenes, triterpenes, flavonoids, and lignans, had been extracted and identified from R. molle. The extracts/monomers isolated from the root, flower and fruits of this plant were used as effective agents for treating pains, inflammatory diseases, hypertension, and pest, etc. In addition, diterpenes, such as rhodojaponin III, were considered as the toxic agents associated with the toxicities of this plant. These findings will be significant for the discovery of new drugs from this plant and full utilization of R. molle.
Subject(s)
Plant Extracts , Plants, Medicinal , Rhododendron/chemistry , Animals , Humans , Medicine, Chinese Traditional , Molecular Structure , Phytotherapy , Plant Extracts/chemistry , Plant Extracts/pharmacology , Plant Extracts/therapeutic use , Plant Extracts/toxicityABSTRACT
We have demonstrated that multiple functionalities of transition-metal dichalcogenide (TMDC) monolayers may be substantially improved by the intercalation of small cations (H+ or Li+) between the monolayers and underlying substrates. The functionalities include photoluminescence (PL) efficiency and catalytic activity. The improvement in PL efficiency may be up to orders of magnitude and can be mainly ascribed to two effects of the intercalated cations: p-doping to the monolayers and reducing the influence of substrates, but more studies are necessary to better understand the mechanism for the improvement in the catalytic functionality. The cation intercalation may be achieved by simply immersing substrate-supported monolayers into the solution of certain acids or salts. It is more difficult to intercalate under the monolayers interacting with substrates stronger, such as as-grown monolayers or the monolayers on 2D material substrates. This result presents a versatile strategy to simultaneously optimize multiple functionalities of TMDC monolayers.
ABSTRACT
Glycogen synthase kinase-3ß (GSK-3ß) acts as a negative regulator of NF-E2 related factor 2 (Nrf2) by inducing Nrf2 degradation and nuclear export. Our previous study demonstrated that the flavonoid hyperoside elicits cytoprotection against oxidative stress by activating the Keap1-Nrf2-ARE signaling pathway, thus increasing the expression of antioxidant enzymes, such as heme oxygenase-1 (HO-1), superoxide dismutase (SOD) and catalase. However, the role of GSK-3ß in hyperoside-mediated Nrf2 activation is unclear. Here, we demonstrate that in a normal human hepatocyte cell line, (L02), hyperoside is capable of inducing the phosphorylation of GSK-3ß at Ser9 without affecting the protein levels of GSK-3ß and its phosphorylation at Thr390. Lithium chloride (LiCl) and short interfering RNA (siRNA)-mediated inhibition of GSK-3ß significantly enhanced the ability of hyperoside to protect L02 liver cells from H2O2-induced oxidative damage, leading to increased cell survival shown by the maintenance of cell membrane integrity and elevated levels of glutathione (GSH), one of the endogenous antioxidant biomarkers. Further study showed that LiCl and siRNA-mediated inhibition of GSK-3ß increased hyperoside-induced HO-1 expression, and the effect was dependent upon enhanced Nrf2 nuclear translocation and gene expression. These activities were followed by ARE-mediated transcriptional activation in the presence of hyperoside, which was abolished by the transfection of the cells with Nrf2 siRNA. Furthermore, the siRNA-mediated inhibition of Keap1 also enhanced hyperoside-induced Nrf2 nuclear accumulation and HO-1 expression, which was relatively smaller than the effects obtained from GSK-3ß siRNA administration. Moreover, Keap1 siRNA administration alone had no significant effect on the phosphorylation and protein expression of GSK-3ß. Collectively, our data provide evidence that hyperoside attenuates H2O2 -induced L02 cell damage by activating the Nrf2-ARE signaling pathway through both an increase in GSK-3ß inhibitory phosphorylation at Ser9 and an inhibition of Keap1 and that hyperoside-mediated GSK-3ß inhibition exhibits more significant effects.
Subject(s)
Antioxidants/pharmacology , Glycogen Synthase Kinase 3/metabolism , Oxidative Stress , Quercetin/analogs & derivatives , Response Elements , Second Messenger Systems , Cell Line , Glycogen Synthase Kinase 3/genetics , Glycogen Synthase Kinase 3 beta , Hepatocytes/drug effects , Hepatocytes/metabolism , Humans , NF-E2-Related Factor 2/metabolism , Quercetin/pharmacologyABSTRACT
BACKGROUND: The objective of this study was to investigate how treatment strategies in the same treatment affected the canine's initial displacement and the stress in periodontal ligament using three-dimensional finite element analysis. And to find out the way to design an effective treatment plan. METHODS: Based on computed tomography images of the teeth and their supporting tissues, solid models were used to build finite element models. Three treatment plans of three different transparent tooth correction therapies finite element-analyses were operated. RESULTS: The canine's initial displacement and stresses' distribution in periodontal ligament were obtained. CONCLUSIONS: For rotation movement, the canine should rotate along tooth long axis, and not combine with other kinds of tooth movement as possible. For translation movement, the combination of translation and inclination movement is helpful for the treatment.
Subject(s)
Finite Element Analysis/statistics & numerical data , Orthodontics/statistics & numerical data , Biomechanical Phenomena , Computer Simulation , Humans , Incisor/metabolism , Models, Biological , Periodontal Ligament/metabolism , Stress, Mechanical , Tooth Movement Techniques/statistics & numerical dataABSTRACT
The objective of this study was to evaluate the efficacy and safety of a traditional Chinese medicine, Fufang Xuelian Burn Ointment (FXBO), to treat superficial and deep second-degree burn wounds. A four-center, randomized, controlled, and prospective study was conducted. Overall, 240 patients with either superficial or deep second-degree burn wounds were enrolled consecutively in this study. Patients who were randomly assigned to the control group (superficial: 72, deep: 48) underwent common burn wound therapy, whereas those randomized to the treatment group (superficial: 72, deep: 48) received common burn wound therapy plus topical FXBO. The healing rate, healing time, effective rate, and safety data were compared between the two groups. The baseline characteristics were comparable for the two groups. The healing rate was 94.79(±7.50) in the control group and 98.60(±5.69) in the FXBO group after 14 days for patients with superficial second-degree burn wounds (P = 0.000), and 95.17(±9.68) versus 97.44(±9.81) at 28 for deep second-degree burn wounds (P = 0.025). The median healing time in the FXBO group were 9 and 21 days for superficial and deep second-degree burns, respectively, compared to 10.5 and 22.5 days, respectively, in control group (P(superficial) = 0.000 and P(deep) = 0.009). The results of the effective rate showed that comprehensive efficacy of the FXBO group was improved compared to the control group for either superficial or deep second-degree burns (P(superficial) = 0.035 and P deep = 0.003). There were no reported drug-related adverse events in both groups. Therefore, FXBO was well tolerated and more effective than control group for treating superficial and deep second-degree burn wounds.
Subject(s)
Burns/drug therapy , Drugs, Chinese Herbal/therapeutic use , Adolescent , Adult , Aged , Burns/physiopathology , Drugs, Chinese Herbal/adverse effects , Female , Humans , Male , Middle Aged , Ointments , Prospective Studies , Safety , Treatment Outcome , Wound Healing/drug effects , Young AdultABSTRACT
We report an investigation on the adsorption of small gas molecules (O(2), CO, NO(2) and NH(3)) on pristine and various transition metal embedded graphene samples using a first-principles approach based on density-functional theory (DFT). The most stable adsorption geometry, energy, charge transfer, and magnetic moment of these molecules on graphene embedded with different transition metal elements are thoroughly discussed. Our calculations found that embedded transition metal elements in general can significantly enhance the interactions between gas molecules and graphene, and for applications of graphene-based catalysis, Ti and Au may be the best choices among all transition metal elements. We also expect a detailed analysis of the electronic structures and magnetic properties of these systems to shed light on future applications of graphene-based gas sensing and spintronics.
ABSTRACT
The aim of the present study was to investigate the therapeutic effect and mechanism of proanthocyanidins from grape seed (GSPE) in the treatment of recurrent ulcerative colitis (UC) in rats. To induce recurrent colitis, rats were instilled with 2,4,6-trinitrobenzenesulfonic acid (TNBS) (80 mg/kg) into the colon through the cannula in the first induced phase, and then the rats were instilled a second time with TNBS (30 mg/kg) into the colon on the sixteenth day after the first induction UC. Rats were intragastrically administered GSPE (200 mg/kg) per day for 7 days after twice-induced colitis by TNBS. Sulfasalazine at 500 mg/kg was used as a positive control drug. Rats were killed 7 days after GSPE treatment. The colonic injury and inflammation were assessed by macroscopic and macroscopic damage scores, colon weight/length ratio (mg/cm), and myeloperoxidase activity. Then, superoxide dismutase, glutathione peroxidase, inducible nitric oxide synthase (iNOS) activities, and the levels of malonyldialdehyde, glutathione, and nitric oxide in serum and colonic tissues were measured. Compared with the recurrent UC group, GSPE treatment facilitated recovery of pathologic changes in the colon after induction of recurrent colitis, as demonstrated by reduced colonic weight/length ratio and macroscopic and microscopic damage scores. The myeloperoxidase and iNOS activities with malonyldialdehyde and nitric oxide levels in serum and colon tissues of colitis rats were significantly decreased in the GSPE group compared with those in the recurrent UC group. In addition, GSPE treatment was associated with notably increased superoxide dismutase, glutathione peroxidase activities, and glutathione levels of colon tissues and serum of rats. GSPE exerted a protective effect on recurrent colitis in rats by modifying the inflammatory response, inhibiting inflammatory cell infiltration and antioxidation damage, promoting damaged tissue repair to improve colonic oxidative stress, and inhibiting colonic iNOS activity to reduce the production of nitric oxide.
Subject(s)
Anti-Ulcer Agents/therapeutic use , Colitis, Ulcerative/drug therapy , Grape Seed Extract/therapeutic use , Proanthocyanidins/therapeutic use , Animals , Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Anti-Ulcer Agents/pharmacology , Colitis, Ulcerative/chemically induced , Colitis, Ulcerative/metabolism , Colitis, Ulcerative/pathology , Colon/enzymology , Colon/metabolism , Colon/pathology , Glutathione/blood , Glutathione/metabolism , Grape Seed Extract/pharmacology , Male , Malondialdehyde/blood , Malondialdehyde/metabolism , Neutrophil Infiltration/drug effects , Nitric Oxide/blood , Nitric Oxide/metabolism , Nitric Oxide Synthase Type II/blood , Nitric Oxide Synthase Type II/metabolism , Organ Size , Oxidoreductases/blood , Oxidoreductases/metabolism , Peroxidase/metabolism , Proanthocyanidins/pharmacology , Random Allocation , Rats , Rats, Wistar , Secondary Prevention , Severity of Illness IndexABSTRACT
The aim of the study was to investigate the therapeutic effect and mechanism of proanthocyanidins from grape seeds (GSPE) in the treatment of ulcerative colitis (UC). Rats were intragastrically administered different doses of GSPE (100, 200, and 400 mg/kg) per day for 7 days after UC was twice-induced by intracolonic injection of 2,4,6-trinitrobenzene sulfonic acid (TNBS)dissolved in 50% ethanol. Sulfasalazine (SASP) at 200 mg/kg was used as a positive control drug. Macroscopic and microscopic damage scores and changes in weight/length ratio (mg/mm) of colon segments were analyzed. The levels of malonyldialdehyde (MDA), interleukin (IL)-1beta, IL-2, IL-4, and myeloperoxidase (MPO) activity in the colon tissues and MPO activity in the serum were all measured by biochemical methods or double antibody sandwich ELISA methods. Compared with the TNBS control group, GSPE treatment facilitated recovery of pathologic changes in the colon after insult with TNBS, as demonstrated by increased body weight (p < 0.01) and decreased colonic weight/length ratio (p < 0.01); GSPE also notably reduced the colonic macroscopic and microscopic damage scores (p < 0.01). The MPO activity in colon tissues and serum of rats treated with GSPE was significantly lower than that in the TNBS control group. The MDA and IL-1beta levels of colon tissues were also decreased in GSPE groups. The intestinal antiinflammatory effect of GSPE was accompanied by a significant improvement of IL-2 and IL-4 levels in the colon tissues of rats in the high-dose GSPE group (p < 0.05). Compared with the SASP group, GSPE groups had no significant difference in the therapeutic effect (p > 0.05). GSPE exerts a beneficial antiinflammatory effect in the acute phase of TNBS-induced colitis in rats by downregulating some of the mediators involved in the intestinal inflammatory response, inhibiting inflammatory cell infiltration and antioxidation damage, promoting damaged tissue repair to improve colonic oxidative stress, decreasing production of proinflammatory cytokines IL-1beta, and increasing production of antiinflammatory cytokines IL-2 and IL-4.