[Feasibility of Automatic Treatment Planning in Intensity-modulated Radiotherapy of Nasopharyngeal Carcinoma].

Intensity-modulated radiotherapy planning for nasopharyngeal carcinoma is very complex. The quality of plan is often closely linked to the experience of the treatment planner. In this study, 10 nasopharyngeal carcinoma patients at different stages were enrolled. Based on the scripting of Pinnacle 9. 2 treatment planning system, the computer program was used to set the basic parameters and objective parameters of the plans. At last, the nasopharyngeal carcinoma intensity-modulated radiotherapy plans were completed automatically. Then, the automatical and manual intensity-modulated radiotherapy plans were statistically compared and clinically evaluated. The results showed that there were no significant differences between those two kinds of plans with respect to the dosimetry parameters of most targets and organs at risk. The automatical nasopharyngeal carcinoma intensity-modulated radiotherapy plans can meet the requirements of clinical radiotherapy, significantly reduce planning time, and avoid the influence of human factors such as lack of experience to the quality of plan.

The Application Potential of Artificial Intelligence and Numerical Simulation in the Research and Formulation Design of Drilling Fluid Gel Performance.

Drilling fluid is pivotal for efficient drilling. However, the gelation performance of drilling fluids is influenced by various complex factors, and traditional methods are inefficient and costly. Artificial intelligence and numerical simulation technologies have become transformative tools in various disciplines. This work reviews the application of four artificial intelligence techniques-expert systems, artificial neural networks (ANNs), support vector machines (SVMs), and genetic algorithms-and three numerical simulation techniques-computational fluid dynamics (CFD) simulations, molecular dynamics (MD) simulations, and Monte Carlo simulations-in drilling fluid design and performance optimization. It analyzes the current issues in these studies, pointing out that challenges in applying these two technologies to drilling fluid gelation performance research include difficulties in obtaining field data and overly idealized model assumptions. From the literature review, it can be estimated that 52.0% of the papers are related to ANNs. Leakage issues are the primary concern for practitioners studying drilling fluid gelation performance, accounting for over 17% of research in this area. Based on this, and in conjunction with the technical requirements of drilling fluids and the development needs of drilling intelligence theory, three development directions are proposed: (1) Emphasize feature engineering and data preprocessing to explore the application potential of interpretable artificial intelligence. (2) Establish channels for open access to data or large-scale oil and gas field databases. (3) Conduct in-depth numerical simulation research focusing on the microscopic details of the spatial network structure of drilling fluids, reducing or even eliminating data dependence.

Safely completed radiotherapy in a patient with breast cancer and right axillary vein approach cardiac pacemaker implantation: A case report.

Pacemaker implantation is becoming increasingly common in patients with breast cancer. Comprehensive treatment options, such as surgery, chemotherapy, radiation therapy, targeted therapy and immunotherapy, have greatly improved the prognosis of patients with breast cancer. In particular, radiotherapy is an important means of comprehensive breast cancer treatment that can reduce recurrence and prolong survival in high-risk patients who underwent mastectomy. The pacemaker electrical pulse generator is typically implanted subcutaneously in the left subclavian area above the pectoral muscle through the subclavian vein. The present report implemented a new method of 'temporary pacemaker electrode and permanent artificial pacemaker placement' through the right axillary vein in a patient with breast cancer. An electrical pulse generator was placed in the right subcutaneous subclavian tissue. The pacemaker was placed under the right clavicle, and the pacemaker was included as organ at risk (OAR). Dose of planning organ at risk volume (PRV) with additional 6 mm margin to the pacemaker was limited during radiotherapy planning design. This patient with breast cancer, who was also complicated with other underlying comorbidities (such as atrial fibrillation, coronary atherosclerosis, cardiac insufficiency, hypertension, type 2 diabetes mellitus) and implanted with a cardiac pacemaker, was treated with safe (means that the patient has not developed heart disease because of the pacemaker problem) and effective (tumor can be effectively controlled under the condition that the pacemaker does not malfunction) radiotherapy. At present, the patient has successfully completed radiation therapy for breast cancer with no recurrence or metastasis. To the best of our knowledge, the present report is the first to document this application, demonstrating the treatment of a patient with breast cancer and cardiac pacemaker implantation, which is worthy of further study and continuous improvement in clinical practice.

An Amphiphilic Multiblock Polymer as a High-Temperature Gelling Agent for Oil-Based Drilling Fluids and Its Mechanism of Action.

Oil-based drilling fluids are widely used in challenging wells such as those with large displacements, deepwater and ultra-deepwater wells, deep wells, and ultra-deep wells due to their excellent temperature resistance, inhibition properties, and lubrication. However, there is a challenging issue of rheological deterioration of drilling fluids under high-temperature conditions. In this study, a dual-amphiphilic segmented high-temperature-resistant gelling agent (HTR-GA) was synthesized using poly fatty acids and polyether amines as raw materials. Experimental results showed that the initial decomposition temperature of HTR-GA was 374 °C, indicating good thermal stability. After adding HTR-GA, the emulsion coalescence voltage increased for emulsions with different oil-to-water ratios. HTR-GA could construct a weak gel structure in oil-based drilling fluids, significantly enhancing the shear-thinning and thixotropic properties of oil-based drilling fluids under high-temperature conditions. Using HTR-GA as the core, a set of oil-based drilling fluid systems with good rheological properties, a density of 2.2 g/cm3, and temperature resistance up to 220 °C were constructed. After aging for 24 h at 220 °C, the dynamic shear force exceeded 10 Pa, and G' exceeded 7 Pa, while after aging for 96 h at 220 °C, the dynamic shear force exceeded 4 Pa, and G″ reached 7 Pa. The synthesized compound HTR-GA has been empirically validated to significantly augment the rheological properties of oil-based drilling fluids, particularly under high-temperature conditions, showcasing impressive thermal stability with a resistance threshold of up to 220 °C. This notable enhancement provides critical technical reinforcement for progressive exploration endeavors in deep and ultra-deep well formations, specifically employing oil-based drilling fluids.

A Nomogram to Predict Critical Weight Loss in Patients with Nasopharyngeal Carcinoma During (Chemo) Radiotherapy.

Background: Weight loss is an important side effect of long-term anticancer treatment for nasopharyngeal carcinoma patients. The decline in body function will cause many adverse effects, such as local recurrence and distant metastasis, and reduce the patient's quality of life. Therefore, this study developed a predictive model for the probability of critical weight loss to provide timely appropriate nutritional interventions and prevent serious side effects. Methods: A 20-week prospective follow-up study of 137 nasopharyngeal carcinoma patients in West China Hospital of Sichuan University undergoing radiotherapy and chemotherapy from February 2018 to March 2020 was conducted to collect relevant clinical data. The clinical usefulness and calibration of the prediction model were assessed using the C-index, calibration plot, receiver operating curve, and decision curve analysis. Internal validation was assessed using bootstrapping validation. Results: The nomogram consisted of sex, smoking status, physical status, chemotherapy regimen, and body mass index. Good calibration was observed for the cohort, with an area under the curve of 0.924. Five independent prognostic factors were included in the nomogram, which showed a high C-index value of 0.815 in the interval validation. Decision curve analysis showed that the nomogram was clinically useful when the intervention was decided at the critical weight loss possibility threshold in the 0% to 97% range. Conclusions: We constructed and validated a nomogram for predicting the incidence of critical weight loss in nasopharyngeal cancer patients undergoing chemotherapy and radiotherapy.

A novel BiOX photocatalyst for the "green" degradation of polymers used in oilfields.

The wastes from functional polymers (polyanionic cellulose, polyacrylamide, potassium polyacrylamide, and hydroxyethyl cellulose) generated during oil and gas exploration and development are harmful to biodiversity and human health. However, most traditional treatments are inefficient in degradation and cause secondary pollution. In this paper, BiOBr0.5Cl0.5 a 3D flower-like solid solution with in-situ deposition of elementary substance Bi and surface oxygen vacancies was synthesized by the hydrolysis and the redox methods. The chemical compositions, the morphologies, and the UV-visible absorption properties of Bi/BiOBr0.5Cl0.5 were characterized. Moreover, the photocatalytic activity of Bi/BiOBr0.5Cl0.5 and the kinetic behavior of the RhB photocatalytic degradation were investigated. The photocatalytic degradation of RhB followed a pseudo-first-order kinetic reaction, and Bi/BiOBr0.5Cl0.5-0.3 demonstrated the highest photocatalytic activity: The RhB degradation efficiency of Bi/BiOBr0.5Cl0.5-0.3 was 85%, and the COD removal rate of the functional polymers conducted by Bi/BiOBr0.5Cl0.5-0.3 was greater than 80%. The exciton photocatalytic processes of Bi/BiOBr0.5Cl0.5 was found through the electron spin resonance (ESR) and the active-species trapping analyses of the photocatalytic degradations of RhB by Bi/BiOBr0.5Cl0.5. In summary, in this paper, the synthesis methods of Bi/BiOBr0.5Cl0.5 photocatalyst and the photocatalytic activity of the Bi/BiOBr0.5Cl0.5 on the degradations of polymers used in oilfields were reported, addressing the shortcomings of the existing treatments for polymer waste fluids that are incorporated into the oil and gas exploration and development process.

Graphene oxide reinforced hemostasis of gelatin sponge in noncompressible hemorrhage via synergistic effects.

Effective hemostasis for noncompressible bleeding has been a key challenge because of the deep, narrow, and irregular wounds. Swellable gelatin is an available hemostatic material but is limited by weak mechanical strength and slow liquid absorption. Herein, the design of a gelatin and graphene oxide (GO) composite sponge (GP-GO) that possesses stable cross-linked networks and excellent absorbability, is reported. The GP-GOs are constructed via the thermal radical polymerization technique, using methacrylate gelatin (Gel-MA) and poly(ethylene glycol) diacrylate (PEGDA) as the crosslinker, while GO is uniformly fixed in the network via the curing reaction to further strengthen the stability. The optimized GP-GO5 with GO addition (5 wt%) exhibits high porosity (> 90%), distinguished liquid absorption rate (106 ms), rapidly responsive swelling (422% expansion within 10 s), and stable mechanical properties. The addition of GO effectively reinforces coagulation stimulation of GP-GOs though the stimulation of platelets and the enrichment effect at the interface, significantly reducing the blood coagulation index (BCI) (< 17.5%). Hemostatic mechanism study indicated the liquid absorbability of GP-GOs is the critical foundation to trigger the subsequent physical expansion, blood cells enrichment, and coagulation stimulations. Besides, GP-GO5 exhibits excellent biosafety assessed by hemolysis and cytotoxicity. Under the synergistic effects, the biocompatible GP-GO5 showed excellent hemostatic properties in the hemostasis of severe bleeding and noncompressible wounds compared with a pure gelatin sponge (GP) and the commercial hemostatic agent Celox™. This study demonstrated a promising candidate for practical application of noncompressible wound hemostasis.

Weight Change Trajectory in Patients With Locally Advanced Nasopharyngeal Carcinoma During the Peri-Radiation Therapy Period.

OBJECTIVES: To analyze the weight change trajectory in patients with locally advanced nasopharyngeal carcinoma (LANPC) before, during, and after radiation therapy for a time span of 40 weeks. SAMPLE & SETTING: 147 patients from a university-affiliated medical center in China were included. METHODS & VARIABLES: Body weight was measured weekly during intensive treatment and biweekly after radiation therapy. RESULTS: All 147 patients experienced critical weight loss during the peri-radiation therapy period. Overall, body weight remained basically unchanged during induction chemotherapy, followed by a sharp and severe decrease during radiation therapy. At 20 weeks after radiation therapy, body weight had increased only slightly from the lowest point. IMPLICATIONS FOR NURSING: A time-tailored intervention based on the weight change trajectory is necessary for patients with LANPC. According to the weight change trajectory, relevant interventions for maintaining body weight should be initiated as early as the second week of radiation therapy and no later than the fourth week of radiation therapy, and these interventions should continue for at least four weeks after radiation therapy.

Hypofraction radiotherapy of liver tumor using cone beam computed tomography guidance combined with active breath control by long breath-holding.

BACKGROUND AND PURPOSE: To evaluate the feasibility and validity of cone beam computed tomography (CBCT) and active breath control (ABC) by long breath-holding in hypofraction radiotherapy of liver tumor. METHODS AND MATERIALS: Twenty-four patients received hypofraction radiotherapy of liver tumor with long breath-holding at end-inhale; four prescriptions were used: 6 Gy×7 (n=8), 10 Gy×4 (n=7), 5 Gy×9 (n=6), 4 Gy×10 (n=3). For each fraction, all patients received pre-correction CBCT scans with ABC, some patients received post-correction and post-treatment CBCT. The interfraction and intrafraction liver positioning errors on medial-lateral (ML), cranial-caudal (CC) and anterior-posterior (AP) directions were obtained. The theoretic margin from clinical target volume (CTV) to planning target volume (PTV) was calculated based on post-treatment error. The dosimetric parameters of PTV and normal tissue were compared between ABC and free breathing (FB). RESULTS: The interfraction error in liver positioning showed system errors (Σ) of 3.18 mm (ML), 6.80 mm (CC) and 3.05 mm (AP); random error (σ) of 3.03 mm (ML), 6.78 mm (CC) and 3.62 mm (AP). These errors were significantly reduced with CBCT guided online correction. The intrafraction systematic error was 0.72 mm (ML), 2.21 mm (CC), 1.49 mm (AP), and random error was 2.30 mm (ML), 3.58 mm (CC), 2.49 mm (AP). Dosimetric parameters such as PTV, the liver's volume included by 23, 30 Gy isodose curve (V23, V30), mean dose to normal liver (MDTNL) and mean dose to cord were significantly larger for FB (P<0.05). CONCLUSION: Liver radiotherapy with long time breath-holding at end-inhale is an effective method to reduce liver motion, PTV and dose to normal tissue. Interfraction and intrafraction liver positioning errors were substantial. CBCT guided online correction of positioning error is recommended for liver radiotherapy with end-inhale ABC.

Expression of hPNAS-4 radiosensitizes Lewis lung cancer.

PURPOSE: This study aimed to transfer the hPNAS-4 gene, a novel apoptosis-related human gene, into Lewis lung cancer (LL2) and observe its radiosensitive effect on radiation therapy in vitro and in vivo. METHODS AND MATERIALS: The hPNAS-4 gene was transfected into LL2 cells, and its expression was detected via western blot. Colony formation assay and flow cytometry were used to detect the growth and apoptosis of cells treated with irradiation/PNAS-4 in vitro. The hPNAS-4 gene was transferred into LL2-bearing mice through tail vein injection of the liposome/gene complex. The tumor volumes were recorded after radiation therapy. Proliferating cell nuclear antigen (PCNA) immunohistochemistry staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were performed to detect the tumor cell growth and apoptosis in vivo. RESULTS: The hPNAS-4 gene was successfully transferred into LL2 cells and tumor tissue, and its overexpressions were confirmed via western blot analysis. Compared with the control, empty plasmid, hPNAS-4, radiation, and empty plasmid plus radiation groups, the hPNAS-4 plus radiation group more significantly inhibited growth and enhanced apoptosis of LL2 cells in vitro and in vivo (P<.05). CONCLUSIONS: The hPNAS-4 gene was successfully transferred into LL2 cells and tumor tissue and was expressed in both LL2 cell and tumor tissue. The hPNAS-4 gene therapy significantly enhanced growth inhibition and apoptosis of LL2 tumor cells by radiation therapy in vitro and in vivo. Therefore, it may be a potential radiosensitive treatment of radiation therapy for lung cancer.

Effects of the proapoptotic regulator Bcl2/adenovirus EIB 19 kDa-interacting protein 3 on radiosensitivity of cervical cancer.

PURPOSE: Bcl2/adenovirus EIB 19 kDa-interacting protein 3 (BNIP3) is a proapoptotic member of the Bcl-2 family. To address its potential as a therapeutic target for radiosensitization, this study investigated the effect of Bnip3 expression on radiosensitivity of cervical cancer in vitro and in vivo. MATERIALS AND METHODS: In vitro: A plasmid expressing the BNIP3 gene was transfected into human cervical cancer HeLa cells using Lipofectamine(2000), and western blot and immunohistochemistry analysis were performed to evaluate the expression of BNIP3 in transfected cells. The effects on radiation-induced apoptosis were investigated using a clone formation assay and flow cytometry. In vivo: A total of 6 × 106 HeLa cells were subcutaneously inoculated into the dorsal flank of nude mice, and plasmids expressing the BNIP3 gene were injected into the mice via the tail vein. Tumor volume was calculated, and immunohistochemistry was used to detect the expression of BNIP3 in tumor cells. TUNEL assays were performed to determine the apoptosis rates in tumor tissues. RESULTS: Transfection with the recombinant BNIP3 plasmid increased expression of the Bnip3 protein in tumor cells. This apoptosis regulator significantly decreased the viability of cells (p < 0.01) and increased the apoptosis rates (p < 0.01) both in vitro and in vivo. The antitumor effect of radiotherapy was enhanced by overexpression of BNIP3, as revealed by tumor growth curve analysis. CONCLUSIONS: Radiosensitization in human cervical cancer cells was observed after treatment with the recombinant BNIP3 plasmid in vitro and in vivo. Results suggested that BNIP3 may play a role in enhancement of radiotherapy efficiency, and its expression may have a synergistic effect on radiation treatments.