Dosimetric risk factors for radiation esophagitis in patients with breast cancer following regional nodal radiation.

BACKGROUND: Radiation esophagitis (RE) is one of the most common clinical symptoms of regi-onal lymph node radiotherapy for breast cancer. However, there are fewer studies focusing on RE caused by hypofractionated radiotherapy (HFRT). AIM: To analyze the clinical and dosimetric factors that contribute to the development of RE in patients with breast cancer treated with HFRT of regional lymph nodes. METHODS: Between January and December 2022, we retrospectively analysed 64 patients with breast cancer who met our inclusion criteria underwent regional nodal intensity-modulated radiotherapy at a radiotherapy dose of 43.5 Gy/15F. RESULTS: Of the 64 patients in this study, 24 (37.5%) did not develop RE, 29 (45.3%) developed grade 1 RE (G1RE), 11 (17.2%) developed grade 2 RE (G2RE), and none developed grade 3 RE or higher. Our univariable logistic regression analysis found G2RE to be significantly correlated with the maximum dose, mean dose, relative volume 20-40, and absolute volume (AV) 20-40. Our stepwise linear regression analyses found AV30 and AV35 to be significantly associated with G2RE (P < 0.001). The optimal threshold for AV30 was 2.39 mL [area under the curve (AUC): 0.996; sensitivity: 90.9%; specificity: 91.1%]. The optimal threshold for AV35 was 0.71 mL (AUC: 0.932; sensitivity: 90.9%; specificity: 83.9%). CONCLUSION: AV30 and AV35 were significantly associated with G2RE. The thresholds for AV30 and AV35 should be limited to 2.39 mL and 0.71 mL, respectively.

Distribution of polycyclic aromatic hydrocarbons in indoor/outdoor window films and the indoor film/air partition of northeastern Chinese college dormitories.

Indoor window films can represent short-term air pollution conditions of indoor environment through rapidly capturing organic contaminants as effective passive air samplers. To investigate the temporal variation, influence factors of polycyclic aromatic hydrocarbons (PAHs) in indoor window films, and the exchange behavior with gas phase in college dormitories, 42 pairs window films of interior and exterior window surfaces and corresponding indoor gas phase and dust samples were collected monthly in six selected dormitories, Harbin, China, from August to December 2019 and September 2020. The average concentration of ∑16PAHs in indoor window films (398 ng/m2) was significantly (p < 0.01) lower than that in outdoors (652 ng/m2). In addition, the median indoor/outdoor ∑16PAHs concentration ratio was close to 0.5, showing that outdoor air acted as a major PAH source to indoor environment. The 5-ring PAHs were mostly dominant in window films whereas the 3-ring PAHs contributed mostly in gas phase. 3-ring PAHs and 4-ring PAHs were both important contributors for dormitory dust. Window films showed stable temporal variation, i.e. PAH concentrations in heating months were higher than those in non-heating months. The atmospheric O3 concentration was the main influence factor of PAHs in indoor window films. PAHs with low molecular weight in indoor window films rapidly reached film/air equilibrium phase within in dozens of hours. The large deviation in the slope of the log KF-A versus log KOA regression line from that in reported equilibrium formula might be the difference between the window film composition and octanol.

Conjugated bilayer structure of the homogeneous solid-liquid interface of metals.

The concept of "interfacial region" has long prevailed for over half century for describing the homogeneous solid-liquid (SL) interface of metals, but its intrinsic structure is still unclear due to the homogeneity. In this study, we reveal, for the first time, the intrinsic structure of these homogeneous SL interfaces consisting of two conjugated monoatomic layers of interfacial solid (IS) and interfacial liquid (IL) with a certain degree of corrugation via molecular dynamics simulations. We named it as the conjugated bilayer structure (CBS). In the framework of CBS, only the IS + IL bilayer plays stepwise transition roles from the solid to the liquid, which defines the four-terrace nature of the interface and act simultaneously as the boundaries of the bilateral bulk phases. The inherent diffuse nature of the "interfacial region" is proven originating from the corrugation of the IS + IL bilayer and its four-terrace nature. More importantly, the CBS also explains that the interfacial free energy originates mainly from the increase in the potential energy of the IS layer relative to its counterpart bulk solid instead of the previously argued entropy loss of the liquid phase. After all these verifications and interpretations, the CBS was verified as the intrinsic structure of the homogeneous SL interface of metals. Accordingly, we argue that the concept of CBS also resolves the volume-bearing flaw of the "interfacial region" concept and can definitively locate the intrinsic surface according to the capillary wave theory.

[Effects of dihydroartemisinin on radiosensitivity of Raji cells].

OBJECTIVE: To study the effects of dihydroartemisinin (DHA) on radiation sensitivity of Raji cells, and explore its mechanisms. METHODS: CCK8 was used to determine the effect of DHA on cell viability of Raji cells; apoptosis, intracellular reactive oxygen speies(ROS) and mitochondrial membrane potential of Raji cells were detected by flow cytometry; and the protein expressions of protein kinase B(AKT), phospho-rylated-protein kinase B(p-AKT), Bcl-2 and Bax were determined by Western blot. RESULTS: The cells were randomly divided into four groups:control group, DHA(5µmol/L DHA), irradiation(IR, 4 Gy), IR+DHA group (4 Gy IR+5 µmol/L DHA). Compared with the other three groups, cells in DHA+IR group exhibited lower mitochondrial membrane potential (P<0.01). While the intracellular ROS content and apoptosis rate of Raji cells in DHA+IR group were increased significantly(P<0.01). In addition, compared with the other three groups, there was no significant difference in the expression of AKT, but the phosphorylation of AKT protein were significantly inhibited and the expression of Bcl-2 protein was markedly decreased. However, the expressions of Bax and Cleaved-Caspase-3 protein were markedly increased. CONCLUSIONS: DHA might activate the mitochondrial apoptotic signal via inhibiting phosphoinositide 3-kinase (PI3K/AKT) pathway and increase oxidative stress to enhance the radiosensitivity of Raji cells.