Non-negligible roles of charge transfer excitons in ultrafast excitation energy transfer dynamics of a double-walled carbon nanotube.

Herein, we employed a developed linear response time dependent density functional theory-based nonadiabatic dynamics simulation method that explicitly takes into account the excitonic effects to investigate photoinduced excitation energy transfer dynamics of a double-walled carbon nanotube (CNT) model with different excitation energies. The E11 excitation of the outer CNT will generate a local excitation (LE) |out*〉 exciton due to its low energy, which does not induce any charge separation. In contrast, the E11 excitation of the inner CNT can generate four kinds of excitons with the LE exciton |in*〉 dominates. In the 500-fs dynamics simulation, the LE exciton |in*〉 and charge transfer (CT) excitons |out-in+〉 and |out+in-〉 are all gradually converted to the |out*〉 exciton, corresponding to a photoinduced excitation energy transfer, which is consistent with experimental studies. Finally, when the excitation energy is close to the E22 state of the outer CNT (∼1.05 eV), a mixed population of different excitons, with the |out*〉 exciton dominated, is generated. Then, photoinduced energy transfer from the outer to inner CNTs occurs in the first 50 fs, which is followed by an inner to outer excitation energy transfer that is completed in 400 fs. The present work not only sheds important light on the mechanistic details of wavelength-dependent excitation energy transfer of a double-walled CNT model but also demonstrates the roles and importance of CT excitons in photoinduced excitation energy transfer. It also emphasized that explicitly including the excitonic effects in electronic structure calculations and nonadiabatic dynamics simulations is significant for correct understanding/rational design of optoelectronic properties of periodically extended systems.

Crosstalk of fibroblast growth factor 23 and anemia-related factors during the development and progression of CKD (Review).

Fibroblast growth factor 23 (FGF23) plays an important role in the development of chronic kidney disease-mineral bone disorder (CKD-MBD). Abnormally elevated levels of 1,25-dihydroxyvitamin D cause osteocytes to secrete FGF23, which subsequently induces phosphaturia. Recent studies have reported that iron deficiency, erythropoietin (EPO) and hypoxia regulate the pathways responsible for FGF23 production. However, the molecular mechanisms underlying the interactions between FGF23 and anemia-related factors are not yet fully understood. The present review discusses the associations between FGF23, iron, EPO and hypoxia-inducible factors (HIFs), and their impact on FGF23 bioactivity, focusing on recent studies. Collectively, these findings propose interactions between FGF23 gene expression and anemia-related factors, including iron deficiency, EPO and HIFs. Taken together, these results suggest that FGF23 bioactivity is closely associated with the occurrence of CKD-related anemia and CKD-MBD.

Effect of alemtuzumab on intestinal intraepithelial lymphocytes and intestinal barrier function in cynomolgus model.

BACKGROUND: Alemtuzumab has been used in organ transplantation and a variety of hematologic malignancies (especially for the treatment of B-cell chronic lymphocytic leukemia). However, serious infectious complications frequently occur after treatment. The reason for increased infections postalemtuzumab treatment is unknown at this stage. We explore the effect of alemtuzumab on intestinal intraepithelial lymphocytes (IELs) and intestinal barrier function in cynomolgus model to explain the reason of infection following alemtuzumab treatment. METHODS: Twelve male cynomolguses were randomly assigned to either a treatment or control group. The treatment group received alemtuzumab (3 mg/kg, intravenous injection) while the control group received the same volume of physiological saline. Intestinal IELs were isolated from the control group and the treatment group (on day 9, 35, and 70 after treatment) for counting and flow cytometric analysis. Moreover, intestinal permeability was monitored by enzymatic spectrophotometric technique and enzyme-linked immunosorbent assay. RESULTS: The numbers of IELs were decreased significantly on day 9 after treatment compared with the control group (0.35 ± 0.07 × 10 8 and 1.35 ± 0.09 × 10 8 , respectively; P < 0.05) and were not fully restored until day 70 after treatment. There were significant differences among four groups considering IELs subtypes. In addition, the proportion of apoptotic IELs after alemtuzumab treatment was significantly higher than in the control group (22.01 ± 3.67 and 6.01 ± 1.42, respectively; P < 0.05). Moreover, the concentration of D-lactate and endotoxin was also increased significantly on day 9 after treatment. CONCLUSIONS: Alemtuzumab treatment depletes lymphocytes in the peripheral blood and intestine of cynomolgus model. The induction of apoptosis is an important mechanism of lymphocyte depletion after alemtuzumab treatment. Notably, intestinal barrier function may be disrupted after alemtuzumab treatment.

Carbon nanostructure modified enzyme-catalyzed biosensor for bio-electrochemical NADH regeneration.

An efficient and biocompatible NADH regeneration system to promote ADH-catalysed oxidation reactions is reported. Carbon nanomaterials facilitate enhanced enzyme attachment within their hierarchical nano-structure. According to enzyme protein molecular computer simulation analysis, different electron transfer efficiencies on CNTs or GNSs enzyme-catalyzed electrodes result in different electric charge distributions around ADH, which affects its molecular spatial arrangement and three-dimensional conformation. The nanostructure enhances the enzyme-electrode interaction and electron transfer rate. 1.4- and 1.9-fold higher current density are reached on CNTs and GNSs, respectively, versus the carbon cloth control for the bio-electrochemical NADH regeneration. Maximum NADH production rates are 2.11 and 3.01 times higher than that on the unmodified carbon cloth control. The use of the efficient carbon nanomaterial electrochemical reactor leads to a highly conductive three-dimensional cathode for the improvement of bio-electrochemical NADH regeneration, making the nanomaterial an extremely efficient material from an engineering perspective as well.

[Study on early postoperative nutritional support in elderly patients with gastric cancer].

OBJECTIVE: To explore the optimal postoperative nutritional support in elderly patients with gastric cancer. METHODS: One hundred and twenty elderly patients with gastric cancer undergoing radical gastrectomy were prospectively enrolled from January 2010 to March 2013 and randomly divided into total parenteral nutrition group(TPN, n=40), early total enteral nutrition group (TEN, n=40) and enteral plus parenteral nutrition group(EN+PN, n=40). Clinical charasteristics including treatment tolerance, nutritional indexes, immune indexes, time to first flatus, incidence of postoperative infection and anastomotic leakage, were analyzed and compared. RESULTS: Treatment tolerance in EN+PN group(97.5%, 39/40) was significantly higher than that in TPN group(82.5%, 33/40) and TEN group(80.0%, 32/40)(both P<0.05). The nutritional indices, including prealbumin, albumin, transferrin, body mass index, and the incidence of anastomotic leakage were similar in the 3 groups(P>0.05). The immune indices, including CD3, CD4, CD4/CD8, were significantly reduced after operation in each group. However, they were significantly higher in EN+PN group and TEN group than those in TPN group(both P<0.05). Furthermore, compared to the TPN group, the incidence of postoperative infection(surgical site infection, pulmonary infection, abdominal infection) was significantly lower and time to first flatus was significantly shorter in EN+PN group and TEN group. CONCLUSIONS: Early enteral nutrition after gastric cancer surgery is safe, simple and feasible. EN plus PN is the best way to administer postoperative nutritional support in elderly patients with gastric cancer.