ABSTRACT
The adsorption and degradation capacities of dichlorodiphenyltrichloroethane (DDT) on a photocatalyst composed of TiO2 supported on the mesoporous material MCM-41 (TiO2/MCM-41) were investigated using density functional theory and real-time density functional theory methods. The van der Waals interactions within the PBE functional were adjusted by using the Grimme approach. The adsorption of DDT was evaluated through analyses involving adsorption energy, Hirshfeld atomic charges, Wiberg bond orders, molecular electrostatic potential, noncovalent interaction analysis, and bond path analysis. The findings reveal that DDT undergoes physical adsorption on pristine MCM-41 or MCM-41 modified with Al or Fe due to the very small bond order (only about 0.15-0.18) as well as the change in total charge of DDT after adsorption is close to 0. However, it chemically adsorbs onto the TiO2/MCM-41 composite through the formation of Ti···Cl coordination bonds because the maximum bond order is very large, about 1.0 (it can be considered as a single bond). The adsorption process is significantly influenced by van der Waals interactions (accounting for approximately 30-40% of the interaction energy), hydrogen bonding, and halogen bonding. MCM-41 is demonstrated to concurrently function as a support for the TiO2 photocatalyst, creating a synergistic effect that enhances the photocatalytic activity of TiO2. Based on the computational results, a novel photocatalytic mechanism for the degradation of DDT on the TiO2/MCM-41 catalyst system was proposed.
ABSTRACT
Adsorption of lindane (HCH) on nickel modified graphitic carbon nitride (Ni-gCN) was investigated using a novel, accurate and broadly parametrized self-consistent tight-binding quantum chemical (GFN2-xTB) method. Two graphitic carbon nitride (gCN) models were used: corrugated and planar, which represent the material with different thicknesses. Electronic properties of the adsorbates and adsorbent were estimated via vertical ionization potential, vertical electron affinity, global electrophilicity index and the HOMO and LUMO. Adsorption energy and population analyses were carried out to figure out the nature of the adsorption process. The results reveal that the introduction of the nickel atom significantly influences the electronic properties of gCN, and results in the improvement of adsorption ability of gCN for lindane. Lindane adsorption on Ni-gCN is considered as chemisorption, which is primarily supported by the interaction of the nickel atom and chlorine atoms of HCH. The effect of solvents (water, ethanol, acetonitrile) was investigated via the analytical linearized Poisson-Boltzmann model. Due to the strong chemisorption, Ni-gCN can collect lindane from different solvents. The adsorption configurations of HCH on Ni-gCN were also shown to be thermally stable at 298 K, 323 K, 373 K, 473 K, and 573 K via molecular simulation calculations. The obtained results are useful for a better understanding of lindane adsorption on Ni-gCN and for the design of materials with high efficiency for lindane treatment based on adsorption-photocatalytic technology.
ABSTRACT
BACKGROUND: Pediatric supracondylar humerus fracture (SHF) is a complicated injury which can result in severe sequela. Nowadays, closed reduction and percutaneous pinning (CRPP) is the most popular treatment. AIM: This study had two aims (1) checking the result of treating pediatric SHF patients without neurovascular injury by CRPP under image intensifier, and (2) analysing neurovascular complications of CRPP in treating these patients. METHODS: We conducted a research on 42 patients from February 2018 to March 2019. The age of patients ranged from 3 to 11 years old, with a mean of 5. There was a male predominance with a male / female ratio of 3/1. The average duration of the procedure was 46 minutes, and there was no failed case. RESULTS: Result evaluation based on Flynn criteria (1974): 85.74 % excellent, 9.5% good, 2.38% fair, and 2.38% poor. There was 1 patient how got ulnar nerve injury complication after medial-lateral crossed pinning, making up 2.38% of all cases. This case was a late admission - 3 days after being injured - and the elbow was badly swollen, so locating the medial condyle for pin placement was very problematic, this the ulnar nerve could be damaged during K-wire pinning. The K-wires are removed after 4 weeks. CONCLUSION: CRPP under image intensifier in treating pediatric supracondylar humerus fracture is an effective treatment and with good treatment result.
ABSTRACT
PURPOSE: We tried to investigate the clinical impact of Ki-67 (MIB-1) expression on the oncological and survival outcomes in patients with bladder cancer (BCa) after the radical cystectomy. MATERIALS AND METHODS: We retrospectively analyzed the data of 230 patients who were treated by radical cystectomy for BCa. Multivariate Cox-proportional hazards models and logistic regression tests were performed to evaluate the prognostic value of each variable. RESULTS: The patients with positive Ki-67 expression showed significant worse clinical characteristics and pathologic outcomes than negative Ki-67 group. Furthermore, the patients with Ki-67 expression showed significant worse recurrence (p=0.018) and cancer-specific mortality free survival (p=0.019) than negative Ki-67 group. The overall survival was also revealed to be inferior in Ki-67 positive group than Ki-67 negative group but the statistical significance was marginal (p=0.062). Subsequent multivariate Cox analyses showed that Ki-67 was independent predictor for disease recurrence after surgery (hazard ratio, 3.142; 95% CI, 1.287–7.671; p=0.012). CONCLUSIONS: In our study, high Ki-67 expression was significantly related with worse clinical outcomes after radical cystectomy in the patients with BCa. Further prospective and basic researches are needed to validate the true prognostic value of Ki-67.
