[en] In order to protect people from irradiation sickness and rebuild the radiation filed in nuclear emergency, personal and environmental dose need to be monitored. The application of TLD in dose monitoring is discussed in this paper. (authors)

[en] Objective: To show the relation between radiation proctitis and maximum absorbed dose at anterior rectal wall in 252 Californium (²⁵²Cf) neutron brachytherapy for uterine cervical cancer. Methods: The absorbed dose at anterior rectal wall of 30 patients was evaluated with shielding by barium enema or lead marker, 15 in each group. Perpendicular isocenter films were taken with the barium or lead marker in place. The dose given at reference point A was 10 Gy. The maximum absorbed dose (Dmax) of anterior rectal wall, posterior bladder wall and the rectal reference point as proposed by ICRU Report 38 were calculated; The distance between the Dmax point at anterior rectal wall, posterior bladder wall and the center of uterine tube were measured by ²⁵²Cf neutron after-loading treatment planning system. Radiation proctitis were analyzed both in the whole group and in patients whose absorbed dose of anterior rectal wall was > 4 Gy. Results: The Dmax at anterior rectal wall evaluated by barium enema was significantly higher than those by lead marker. The distance between the Dmax point at anterior rectal wall and the center of uterine tube was significantly lower by barium enema than those by lead marker. The dose of Dmax point at posterior bladder wall, the distance between the Dmax point at posterior bladder wall and the center of uterine tube in these two groups were not significantly different. The morbidity of acute radiation proctitis in patients whose Dmax of anterior rectal wall >4 Gy were significantly higher than in those < 4 Gy patients. Conclusions: Barium enema, being able to show better the anatomic relation between cervix, vagina and anterior rectal wall than lead marker, is able to reflect the real absorbed dose at the anterior rectal wall more accurately, Acute radiation proctitis can be predicted according to Dmax at anterior rectal wall. Moreover, the variation of sigmoid position can also be detected by barium enema at the same time. (authors)

[en] Electrospinning has the advantages of large specific surface area and high porosity, and the nanofibers prepared by it can be widely used in environmental engineering, wound dressing, scaffold materials, biomedicine and other fields. Because gelatin is a biological material with biodegradable and good biocompatibility properties; while poly(L-lactide-co-ε-caprolactone) (PLCL) is a biological material with excellent mechanical properties and good biocompatibility. Therefore, the prepared PLCL/gelatin nanofiber membrane has good biocompatibility, and has minimal repellency to the body during clinical use, and is effective as a scaffold material. This article uses PLCL and gelatin as experimental materials to study the development and optimization of fiber scaffold materials. First introduce the existing tissue engineering scaffold materials, and then describe the basic principles of electrospinning technology. Used 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as solvent to prepare PLCL/GE spinning solution and prepare nanofiber membranes with different total concentrations and different ratios of PLCL to GE, then used the electrospinning process as preparation method to spin nanofiber membranes separately, and the microstructure and hydrophobic performance parameters of the nanofibers were tested and characterized. (paper)

[en] Objective: To compare the efficacy between californium-252 (²⁵²Cf) neutron intraluminal brachytherapy combined with external-beam radiotherapy with lead-shielding pelvic parallel opposing field technique and non-lead-shielding four-field box technique for cervical cancer. Methods: A total of 52 patients with stage II_a-III_b cervical squamous cell carcinoma who were admitted to our hospital from 2004 to 2007 were enrolled as subjects and paired by clinical stage, age, tumor size, and degree of anemia. The 26 pairs of patients were divided into lead-shielding pelvic parallel opposing field group (lead-shielding group) and non-lead-shielding four-field box group (non-lead-shielding group). For all patients in both groups, ²⁵²Cf neutron brachytherapy was added in external-beam radiotherapy. The local control (LC), overall survival (OS), and disease-free survival (DFS) rates were calculated using the Kaplan-Meier method and analyzed using the log-rank test. The difference in the incidence of late complications was analyzed using the McNemar method. Results: There were significant differences in 5-year LC, OS, and DFS rates between the lead-shielding group and the non-lead-shielding group (85% vs. 81%, P = 0.014; 89% vs. 73%, P = 0.013; 89% vs. 73%, P = 0.013). There was also significant difference in the incidence of late complications between the lead-shielding group and the non-lead-shielding group (12% vs. 23%, P = 0.008). Conclusions: When intraluminal brachytherapy combined with external-beam radiotherapy is used to treat cervical cancer, the centers of the front and back fields should be shielded by lead, regardless of whether the parallel opposing field technique or the four-field box technique is used. (authors)

[en] Diamond-like carbon (DLC) films were prepared with CH₄-Ar using a capacitively coupled plasma enhanced chemical vapor deposition (CCP-CVD) method driven by dual-frequency of 41 MHz and 13.56 MHz in combination. Due to a coupling via bulk plasma, the self-bias voltage depended not only on the radiofrequency (RF) power of the corresponding electrode but also on another RF power of the counter electrode. The influence of the discharge parameters on the deposition rate, optical and Raman properties of the deposited films was investigated. The optical band decreased basically with the increase in the input power of both the low frequency and high frequency. Raman measurements show that the deposited films have a maximal sp³ content with an applied negative self-bias voltage of -150 V, while high frequency power causes a continuous increase in the sp³ content. The measurement of atomic force microscope (AFM) shows that the surface of the deposited films under ion-bombardment becomes smoother than those with non-intended self-bias voltage.

[en] The ²⁵²Cf neutron brachytherapy devices were designed and manufactured after solving those problem: the shield difficulties for ²⁵²Cf neutron; the method and facilities for ²⁵²Cf neutron source deliver; the dose calculation and measurement for ²⁵²Cf neutron. From 1999 to 2009, more than twenty ²⁵²Cf neutron brachytherapy devices had been installed in China. The Chinese radiation oncologists implemented the ²⁵²Cf neutron brachytherapy on more than 5000 different kinds of cancer patients, including cervix cancer; endometrium cancer and achieved ideal results. For special presentation, they had breakthrough on radical treatment for low lying rectal adenocarcinoma with sphincter preservation and melanoma patients after the modification of ²⁵²Cf neutron intracavitary applicator and dose calibration. (authors)

[en] Highlights: • This review discusses the photolysis and radical-induced oxidation of DBPs. • ε₂₅₄ and ∆E can predict the rate constants of DBPs under LP-UV irradiation. • The photolysis rates of N-nitrosamines are higher than those of halogenated DBPs. • ^• OH contributes to < 30% of DBPs removal except iodo-DBPs in UV/H₂O₂ AOPs. • Some knowledge gaps exist in technology and radical-induced mechanisms toward DBPs. This review focuses on the degradation kinetics and mechanisms of disinfection byproducts (DBPs) under UV and solar irradiation and in UV-based advanced oxidation processes (AOPs). A total of 59 such compounds are discussed. The processes evaluated are low pressure, medium pressure and vacuum UV irradiation, solar irradiation together with UV/hydrogen peroxide, UV/persulfate and UV/chlorine AOPs. Under UV and solar irradiation, the photodegradation rates of N-nitrosamines are much higher than those of halogenated DBPs. Among halogenated DBPs, those containing iodine are photodegraded more rapidly than those containing bromine or chlorine. This is due to differences in their bond energies (E_N−N < E_C−I < E_C−Br < E_C−Cl). Molar absorption coefficients at 254 nm and energy gaps can be used to predict the photodegradation rates of DBPs under low pressure UV irradiation. But many DBPs of interest cannot be degraded to half their original concentration with less than a 500 mJ cm⁻² dose of low pressure UV light. HO^• generally contributes to less than 30% of the degradation of DBPs except iodo-DBPs in UV/H₂O₂ AOPs. Reaction mechanisms under UV irradiation and in HO^• -mediated oxidation are also summarized. N−N bond cleavage initiates their direct UV photolysis of N-nitrosamines as C−X cleavage does among halogenated compounds. HO^• generally initiates degradation via single electron transfer, addition and hydrogen abstraction pathways. Information on the reaction rate constants of SO₄^{• −} and halogen radicals with DBPs is rather limited, and little information is available about their reaction pathways. Overall, this review provides improved understanding of UV, solar and AOPs.

[en] Pd-doped Ti/SnO₂-Sb anode was prepared at different calcination temperatures by a wet-impregnation method and employed in simultaneous electrochemical catalytic degradation of Ni-EDTA and recovery of nickel. The results showed that Ti/SnO₂-Sb-Pd-500 could achieve the highest electrochemical activity (87.5% of Ni-EDTA removal efficiency), superior durability (50.7 h of accelerated lifetime), and higher Ni recovery (19.8%) on cathode. Cyclic voltammetry (CV) and linear sweep voltammetry (LSV) analysis suggested that Ni-EDTA degradation on anode was mainly indirect oxidation-controlled reaction, attributing to the high oxide state of MO_X + 1 and MO_X(·OH), rather than direct oxidation. Scanning electron microscope (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses indicated that calcination temperature could modify the morphology of electrode surface and affect the incorporation and valence state transformation of metal species (Sb and Pd) in SnO₂ lattice. Ti/SnO₂-Sb-Pd-500 achieved the highest electrochemical capacity with the highest levels of adsorbed oxygen O_ads/E_T (27.11%) and lattice oxygen O_lat/E_T (29.69%). Moreover, the operation conditions for Ni-EDTA electrochemical degradation were optimized. These findings were valuable for developing a high-performance electrode for Ni-EDTA electrochemical degradation.

[en] Highlights: • A staggered-projection Godunov-type scheme is proposed for the full Baer-Nunziato (BN) two-phase model. • The continuity of Riemann invariants across porosity jumps is fully taken into account. • The generalized Riemann problem (GRP) solver is applied to achieve the second order accuracy. When describing the deflagration-to-detonation transition in solid granular explosives mixed with gaseous products of combustion, a well-developed two-phase mixture model is the compressible Baer-Nunziato (BN) model of flows containing solid and gas phases. As this model is numerically simulated by a conservative Godunov-type scheme, spurious oscillations are likely to generate from porosity interfaces, and may result from the average process of conservative variables that violates the continuity of Riemann invariants across porosity interfaces. In order to reduce numerical oscillations, this paper proposes a staggered-projection Godunov-type scheme over a fixed gas-solid staggered grid, by enforcing that compaction waves with porosity jumps are always inside gaseous grid cells and other discontinuities appear at gaseous cell interfaces. The scheme is based on a standard Godunov scheme for the Baer-Nunziato model on gaseous cells and guarantees the continuity of the Riemann invariants associated with the compaction waves across porosity jumps. While porosity interfaces are moving, a projection process fully takes into account the continuity of associated Riemann invariants and ensures that porosity jumps remain inside gaseous cells. Furthermore, the generalized Riemann problem (GRP) solver is applied, not only to achieve second-order accuracy, reduce numerical oscillations, but guarantees the well-balanced property of the resulting scheme as well.

[en] Purpose: To observe, by retrospective analysis, the curative effects and complications due to californium-252 (²⁵²Cf) neutron intracavitary brachytherapy (ICBT) combined with external-beam radiotherapy (EBRT) in the treatment of cervical cancer. Methods and Materials: From February 1999 to December 2007, 696 patients with cervical cancer (Stages IB to IIIB) were treated with ²⁵²Cf-ICBT in combination of EBRT. Of all, 31 patients were at Stage IB, 104 at IIA, 363 at IIB, 64 at IIIA, and 134 at IIIB. Californium-252 ICBT was delivered at 7–12 Gy per insertion per week, with a total dose of 29–45 Gy to reference point A in three to five insertions. The whole pelvic cavity was treated with 8-MV X-ray external irradiation at 2 Gy per fraction, four times per week. After 16–38 Gy of external irradiation, the center of the whole pelvic field was blocked with a 4-cm-wide lead shield, with a total external irradiation dose of 44–56 Gy. The total treatment course was 5 to 6 weeks. Results: Overall survival rate at 3 and 5 years for all patients was 76.0% and 64.9%, respectively. Disease-free 3- and 5-year survival rates of patients were 71.2% and 58.4%, respectively. Late complications included vaginal contracture and adhesion, radiation proctitis, radiation cystitis, and inflammatory bowel, which accounted for 5.8%, 7.1%, 6.2%, and 4.9%, respectively. Univariate analysis results showed significant correlation of stage, age, histopathologic grade, and lymph node status with overall survival. Cox multiple regression analysis showed that the independent variables were stage, histopathologic grade, tumor size, and lymphatic metastasis in all patients. Conclusion: Results of this series suggest that the combined use of ²⁵²Cf-ICBT with EBRT is an effective method for treatment of cervical cancer.