y. liu

In extremely cold environments, the phenomenon of spray impacting on surfaces is unavoidable and the fuel film attached to the surface is one of the crucial factors influencing emission, stability, and cold-start performance in internal combustion engines. However, there is currently a lack of research on the effects of spray impacting on ultra-cold surfaces. In this study, researchers investigated the effect of surface temperature on impinging spray and fuel film area with different values of injection pressure, injection duration, and surface roughness visually using backlight and scattering methods. The penetration and diameter of the impinging spray were not affected by the low surface temperature due to the ample momentum, whereas the height was slightly decreased at the ultra-cold surface. The fuel film area significantly decreased with the lower surface temperature and the shorter injection duration. An empirical correlation for the fuel film area was established for reflecting the relationship between the fuel film area and the low surface temperature or injection conditions. The decrease in fuel film area was more noticeable on the surface with lower temperature and higher surface roughness (Ra=17.69μm). Nevertheless, the longer injection duration weakened this decreasing trend. With the increasing number of injections, the fuel film area rose while the area on the ultra-cold surface, increased more slowly because of the higher viscosity and thickness of the previous residual film.

This paper presents two-dimensional numerical simulations of the self-excited forces on two bridge decks: a streamlined one (Great Belt Bridge) and a bluff one (Sunshine Skyway Bridge). It employs forced vibration simulations using the Open-source code OpenFOAM for flutter derivative identifications. A wide sensitivity study is conducted on the effects of turbulence model, Reynolds number, vibration amplitude, and wind attack angle on flutter derivative identifications. The key findings are as follows. (i) k-ε model shows its superiority in simulating self-excited forces on a bluff bridge deck, while SST k-ω exhibits advantages in the case of a streamlined bridge deck. (ii) Compared with a streamlined bridge deck, flutter derivatives of a bluff bridge deck are more sensitive to the Reynolds number due to the generation of more vortices resulting from flow separation. Both the generation and convection of the vortices are largely affected by the Reynolds number. (iii) Flutter derivatives of the bridge decks can be considered as constants if the vertical amplitude ratio and torsional amplitude are lower than 0.025 and 2°, respectively. Increasing vibration amplitude may result in remarkable variations of some flutter derivatives. (iv) The angle of attack changes the flutter derivatives by affecting the wind pressure distribution on the bridge surface. Its impact on a bluff bridge deck is larger than on a streamlined bridge deck. Besides presenting a detailed study of identifying flutter derivatives using OpenFOAM, this research provides valuable references for setting reasonable values of the investigated factors for identifying flutter derivatives of bluff and streamlined bridge decks.

Experimental testing is an important method for studying centrifugal compressors. However, test rigs with rotating impellers are costly in terms of construction and operating expenses. To address this issue, this study introduces a stationary component performance test rig for centrifugal compressors using an existing wind tunnel. The rig comprises a blower to supply compressed air, a wind tunnel, and a test section of stationary centrifugal compressor model stage. Specially designed stationary guide vanes substitute the impeller to simulate the impeller outlet flow field. Flow field parameters are measured at the inlet and outlet of each model-scale stationary component using a five-hole probe. Measured results can be used to evaluate the performance of each stationary component. Comparison between measured data and CFD results reveals that the measurement results are in good agreement with CFD results. This validates the reliability of the built test rig and measurement. Afterwards an improved diffuser and return channel of the same centrifugal compressor model stage is tested. The experimental results show a 4% reduction in total pressure loss coefficient and a 1% increase in static pressure recovery coefficient compared to the original structure. These results align with the findings obtained on a rotating test rig, indicating the feasibility of the proposed stationary component aerodynamic performance test rig.

Multi-blade centrifugal fans find wide application across various fields, with their internal airflow exhibiting complex turbulent behavior in three dimensions. Historically, blade optimization relied on constant thickness airfoils, limiting the effectiveness of optimization efforts. However, marine organisms have developed airfoil structures with highly efficient drag reduction, offering a novel approach to optimizing multi-blade centrifugal fans. This study proposes an airfoil optimization design method utilizing variable-thickness airfoils to maintain consistent pressure surface leading-edge parameters. By integrating the Non-dominated Sorting Genetic Algorithm II with biomimetic optimization design, performance improvements are achieved. The study constructs an asymmetric bionic blade using a Bezier curve to fit the mean camber line of the blade. Experimental testing validates the optimized fan's performance, demonstrating the effectiveness of the proposed design approach in reducing the unsteady interaction between the impeller and the volute tongue. This reduction significantly diminishes sound pressure fluctuations on the blade surface. Notably, at the maximum volume flow rate, the optimized fan featuring the asymmetric bionic blade exhibits a remarkable enhancement, with a 10.5% increase in volume flow rate and a notable 1.7 dB reduction in noise compared to the original fan configuration.

Medulloepithelioma (MEPL) of the central nervous system (CNS) was once considered as a rare malignant embryonic tumor of the nervous system. The new classification of central nervous system tumors classified it as an Embryonal tumor with multilayered rosettes (ETMR), and its diagnosis depends on immunophenotype and molecular detection in addition to histology. This kind of tumor rarely occurs in adults, and the best treatment is uncertain. This case reports a case of adult MEPL, which mainly shows numbness of limbs. Magnetic resonance imaging (MRI) of the head showed a well-defined tumor near the meninges of the parietal lobe with small cystic changes, which was unevenly enhanced on enhanced scanning. The patient's local recurrence was confirmed within 18 months after complete resection of the tumor by simple operation, and radiotherapy and chemotherapy were given after the second operation. There was no disease progress 32 months after operation. According to our report, it can be speculated that operation, craniospinal radiotherapy (CSI) plus tumor bed boost and high dose chemotherapy are of great value to improve the prognosis of MEPL/ETMR.

While neonatal pneumothorax (NP) is uncommon, it presents a serious condition requiring immediate and precise diagnosis and treatment. To achieve this, dependence on imaging techniques is crucial for detecting gas accumulation within the infant's thoracic cavity. Traditionally, diagnosing NP relies heavily on Chest X-ray (CXR) examinations, involving ionizing radiation exposure, a persisting concern. Conversely, lung ultrasonography (LUS) has gained widespread recognition due to its convenience, expediency, and radiation-free attributes. The debate over whether LUS can completely replace traditional CXR remains contentious. Our objective is to conduct a thorough analysis of the efficacy of LUS and CXR examinations in diagnosing NP, with the intention of offering additional references for clinicians to optimize medical care for infants, minimizing radiation exposure and ensuring comprehensive protection of their health and safety.

Isolated centrifugal fans are widely utilized in air conditioning system and their performance is closely related to the energy consumption of the system. The purpose of this work is to enlarge the fan operation range without reducing peak efficiency. An improved class and shape function method coupled the Kriging model is proposed to design fan airfoils and to optimize the efficiency and static pressure of the fan. Numerical simulation and experimental study show that both pressure coefficients in large and small flow rate are improved by this optimized fan, and the peak efficiency remains to be unchanged almost under design condition. Optimized pressure coefficient increased by 2.17% in design condition. Furthermore, operation range of the isolated centrifugal fan is enlarged via optimization design scheme and surrogate model. A better understanding of the physical mechanisms involved isolated centrifugal fan is further investigated.

The return-channel of a preceding stage in a multi-stage centrifugal compressor has a significant effect on the aerodynamic performance of the current and subsequent stages. However, due to the relatively complex nature of the return-channel configuration with many geometric parameters, no general design guidance is available in the literature. In this study, numerical methods are used to study the effects of different geometric parameters of a return-channel on the performance of a high-flow-coefficient centrifugal compressor. A multi-objective genetic algorithm is applied to optimize the return-channel. The effects of different geometric parameters on the performance are then studied using a sensitivity analysis method. Calculation results show that the residual vortex intensity at the outlet of the return-channel is affected by the geometric angles of the inlet and outlet of the return-channel blades. The flow uniformity at the stage outlet is primarily affected by the geometric angle of the blade outlet and the number of blades. The overall performance of the compressor stage is primarily affected by the geometric angle of the blade inlet and the lateral inclination angle of the cover plate. Calculation results for a two-stage compressor consisting of the optimized first stage and its following stage show that the outlet flow field of the first stage is more uniform than the original first stage. Additionally, at the design operating condition, the polytropic efficiency and pressure ratio of the entire unit increase by 1.07% and 4.07%, respectively. The polytropic efficiency and pressure ratio for the second stage increase by 2.34% and 3.51%, respectively. The impeller head coefficient increases by 7.33%. The theoretical analysis shows that for high-flow-coefficient centrifugal compressors, reducing the residual vortex intensity of the outlet flow field of the return-channel in a stage can significantly improve the off-design performance of the following stage.

This paper studies the evolution and fluid distribution characteristics of a high-speed projectile’s cavity in the water based on joint research, a method involving experiment and numerical simulation. Specifically, we develop an experimental platform and a numerical calculation model for a high-speed projectile to observe its initial cavity evolution characteristics in the water at different velocities and close ranges. Additionally, this work investigates the evolution mechanism of the cavitation process and its fluid distribution law inside the cavity and studies the evolution characteristics of the cavitation stage under different velocities. The results reveal that after the projectile enters the water, the cavity is gourd-shaped and symmetrical, with a necking phenomenon at the tail and the cavity falling off. The cavitation process can be divided into the surface closure, saturation, deep closure, and collapse stages according to the fluid distribution changes in the cavity. Suppose the projectile has a certain speed with the water, its velocity increases. In that case, the cavity generation rate decreases, the growth rate of the water vapor volume in the cavity decreases, the peak water vapor volume content reduces, and the volume of air in the saturation phase of the cavity becomes increases having a range of 6% to 9%. Additionally, the cavity surface closure dimensionless time grows logarithmically as the velocity changes from 0 m/s to 500 m/s, the cavity saturation dimensionless time decreases approximately linearly, and the cavity depth closure dimensionless time is unaffected by velocity changes.

The principle of treatment of pediatric tumors is to kill tumors to the greatest extent and improve long-term quality of life through surgery, radiotherapy, chemotherapy, and other means combined according to the specific disease and pathological type. Radiotherapy is an important means for the treatment of pediatric tumors. With the development of radiotherapy technology, it plays an increasingly important role in clinical work. This paper briefly summarizes the characteristics of radiotherapy in pediatric tumors and introduces the application of radiotherapy in some major pediatric tumors.

Relevant articles published in the PubMed database between 2010 and 2022 were searched. The researchers then looked at the data one by one and looked at the citation, which was their reference at the end of each paper. Inclusion criteria were, articles describing radiation therapy for pediatric tumors; experimental and clinical studies of different radioactive means; and standard methods and rigorous thinking. Exclusion criteria were, meta-analysis article; the literature was published before 2010.

In this paper, radiation therapy for acute lymphoblastic leukemia, Hodgkin's lymphoma, non-Hodgkin's lymphoma, neuroblastoma, retinoblastoma, glioma, Wilms's tumor and rhabdomyosarcoma is summarized and their characteristic radiation conditions are analyzed.

Radiotherapy for children with tumors should not blindly pursue high-dose radiotherapy, but the combination of different therapeutic methods should be adopted to achieve the purpose of tumor treatment and minimize the impact on the growth and quality of life of patients.

To explore the impact of head and neck computed tomography (CT) guided nerve interventional therapy in ischemic cerebrovascular disease (ICVD) patients.

Patients with ICVD (n=100) admitted to our hospital from December 2021 to December 2022 were selected and randomly allocated into control group (CG) and observation group (OG). The CG received drug treatment, and the OG drug treatment before surgery and treated with head and neck CT combined with nerve intervention therapy. Interventional therapy was conducted via endovascular stenting. The National Institute Health of Stroke Scale (NIHSS) score, activities of daily living (ADL) score, vascular recanalization rate, blood flow of the diseased vessels along with occurrence of adverse reactions in both groups were compared.

After therapy, NIHSS score in both groups was declined, and lower in the OG relative to the CG (P<0.05), while ADL score in both groups was elevated, and higher in the OG relative to the CG (P<0.05). The vascular recirculation rate of the OG was 86.00%, higher relative to 60.00% in the CG (P<0.05). Vs (peak systolic flow velocity) and Vd (end diastolic flow velocity) in both groups was lessened post treatment, and lower in the OG relative to the CG (P<0.05). The occurrence of adverse reactions in two groups showed no significant difference (P>0.05).

CT guided nerve interventional therapy was effective for the treatment of ICVD patients, which promoted vascular recanalization and nerve function recovery, effectively improve vascular endothelial function and cerebral blood flow of patients, and improve patient life quality.

Compact aero-engines that use centrifugal compressors are in high demand due to their small size and cost-effectiveness. However, limited improvements in the aerodynamic performance of centrifugal impellers have led to a greater focus on improving the performance of diffusers. This paper introduces a novel vane conformal diffuser designed to match an impeller with a high pressure ratio. The diffuser utilizes a unique design method that creates transitions from a two-dimensional meridian to a three-dimensional configuration, to achieve a twisted design for the vane and hub. Eventually an integrated vane configuration is formed from the radial section to the bend and axial sections. The novel diffuser significantly reduces the radial size of the entire compressor compared with a conventional vaned diffuser. Different cross-section area distributions are studied to explore the reasonable static pressure recovery ability of the diffuser. To validate the new concept, the diffusers of two existing high-pressure centrifugal compressors are redesigned using the novel conformal diffuser configuration. The numerical results show that the aerodynamic performances of the two redesigned centrifugal compressors are improved in terms of both the total pressure ratio and the isentropic efficiency compared with their counterparts. These results demonstrate the effectiveness and applicability of the developed design method for the novel conformal diffuser.

The aim of this study was to make a comparison of plan quality between MLC-based EDGE and the cone-based CyberKnife systems in SBRT of localized prostate cancer.

Ten patients with target volumes from 34.65 to 82.16 cc were included. Treatment plans were created for both systems using the same constraints. Dosimetric indices including target coverage, conformity index (CI), homogeneity index (HI), gradient index (GI) were applied for target, while the sparing of critical organs was evaluated with special dose-volume metrics and integral dose. Meanwhile, the delivery time and monitor units (MUs) were also estimated. The radiobiological indices such as equivalent uniform dose (EUD), tumor control probability (TCP) and normal tissue complication probability (NTCP) were also analyzed.

Both plans produced similar target coverage, HI and GI. For EDGE, more conformal dose distribution as well as reduced exposure of critical organs were obtained together with reduction of 91% delivery time and 72% MUs. EDGE plans also got lower EUD for bladder, rectum, urethra and penile bulk, which associated with reduction of NTCPs. However, higher values of EUD and TCP for tumor were obtained with CK plans.  

It indicated that both systems were capable of producing almost equivalent plan quality and can meet clinical requirements. CyberKnife has higher target dose while EDGE system has more advantages in normal tissue sparing and delivery efficiency.

To investigate the clinical efficacy of hyperthermic intraperitoneal chemotherapy in combination with the malignant ascites in gastric cancer following the Intensive preoperative radiotherapy for radical surgery of tumor.

We selected a total of 112 gastric cancer patients who had been operated on for radical surgery of tumor in this hospital as subjects that were randomized into the control group and the observation group, with 56 patients in each group. Patients in the control group took the abdominal aspiration in combination with the intravenous chemotherapy, while those in the observation group underwent the hyperthermic intraperitoneal chemotherapy. After treatment, we compared the effectiveness rate, levels of tumor markers, incidence rates of adverse reactions, and  Karnofsky (KPS) scores between the two groups.

In the observation group and the control group, the effectiveness rates of patients were 71.43% and 44.64%, showing the statistical significance of the difference (P < 0.05); after treatment, the levels of CEA, CA125, and CA199, tumor markers, were decreased compared to before treatment (P < 0.05). The incidence rates of adverse reactions were 75.00% and 82.14%, showing no statistical significance of difference (P > 0.05). Following the treatment, the KPS scores were improved in two groups compared to before treatment (P < 0.05).

For gastric cancer patients with malignant ascites, hyperthermic intraperitoneal chemotherapy excels in the clinical efficacy by decreasing the level of tumor markers, to improve the life quality of patients, but with no increase in the incidence rate of adverse reactions.

When combustion instability occurs, fluctuation in the release of heat couples with oscillating pressure, while the sensitivity of flame to acoustic disturbance restricts the oscillation intensity. This paper investigates the efficacy of helium in suppressing combustion instability. The flame structure, its sensitivity to acoustic disturbance and the inhibition of oscillating pressure with the addition of helium were studied by means of open tests, external-excited and self-excited combustion instability experiments. First of all, the addition of helium made larger flame surface area, which shaped the distributed flame, and the heat was such released over a broader space. Then, the external-exited combustion instability experiments confirmed that adding helium to fuel could decrease the sensitivity of flame to acoustic disturbance. Finally, Helium was used in the case of self-excited combustion instability to further investigate its effectiveness on the oscillation suppression. Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) methods were used to study flame fluctuation intensity. The results showed that the amplitudes of oscillating pressure were greatly reduced by the added helium. For 250Hz mode, adding helium with 20% of fuel flow could significantly reduce the flame pulsation and reduce the pulsation pressure by more than half. However, for the 160hz mode, more helium should be added to achieve better results. When the helium flow exceeded 80% of fuel flow, the combustion instability could be converted to stable combustion.

The passive suppression of combustion instability by quarter wavelength tube was hereby studied to absorb the oscillation pressure with large amplitudes caused by combustion instability. The suppression effects of quarter wavelength tube on combustion instability were systematically analyzed by combining the acoustic numerical simulation and the experimental research methods. Firstly, the influence of quarter wavelength tube on the acoustic characteristics of the system was analyzed using acoustic numerical simulation; and then, the acoustic absorption characteristics to external acoustic disturbance and the suppression effects on the self-excited combustion instability were experimentally studied. The results show that the quarter wavelength tube can effectively absorb the acoustic pressure when the dominant frequency of acoustic pressure is close to the resonance frequency of the system, and can effectively suppress the combustion instability under acoustic resonance. However, given that the quarter wavelength tube adds adjoint dominant frequencies after eliminating the original resonant frequency of the system, and the combustion instability is stabilized on the adjoint dominant frequencies, combustion instability suppression is different from noise suppression. In addition, the diameter of wavelength tube exercises obvious effects on the above characteristics. All these make it necessary to determine the best parameters and the maximum suppression efficiency by combining numerical simulation and experiments. The research results of this paper provide theoretical and technical supports for the suppression of combustion instability by the quarter wavelength tube.

To explore the efficacy and optimal modality of three-dimensional (3D) MRI sequences in the preoperative detection of neurovascular compressions (NVCs) in patients with trigeminal neuralgia (TN).

Forty-nine cases of typical unilateral TN had undergone 3D time-of-flight magnetic resonance angiography (3D-TOF MRA), 3D fast imaging employing steady-state acquisition (3D-FIESTA), and contrast-enhanced 3D spoiled gradient-recalled sequence (3D-SPGR) on a 3 Tesla MR scanner. Neurovascular relationships (including neurovascular contact and position and the nature of the offending vessels) on MR images were reviewed by a neuroradiologist who was unaware of the clinical findings. Subsequently, microvascular decompression (MVD) surgery was performed on all patients. Comparison was made between the imaging results and surgical findings.

MVD verified NVC in 48 (98%) symptomatic nerves, while 3D-TOF MRA, 3D-FIESTA, and 3D-SPGR revealed NVC in 38 (78%), 48 (98%), and 47 (96%) cases, respectively. Agreement between the position of NVC, as defined by 3D-FIESTA (κ = 0.86) or 3D-SPGR (κ = 0.83) and surgical findings, was excellent. Moreover, excellent agreement was confirmed between the nature of compressing vessels as defined by 3D-FIESTA in combination with 3D-TOF MRA (κ = 0.95) or contrast-enhanced 3D-SPGR in combination with 3D-TOF MRA (κ = 0.92) and surgical findings.

NVCs were visualized with good sensitivity and specificity with 3D MRI sequences in TN. We propose that 3D-FIESTA combined with 3D-TOF MRA is a safe, convenient, and efficacious MRI sequence for revealing NVCs and is crucial for the preoperative diagnosis and surgical planning of MVD.

The study of intelligent design methods is becoming a hot topic for the design of turbine cascades. This paper proposes a data-based policy model to achieve intelligent design. To gain a high-quality policy model, empirical equations and "space extending + elitism" are adopted to dynamically optimize database. This guarantees the quality of the model. Compared to traditional optimization design approaches, the proposed method relies on less human experience to design a turbine cascade. Ten different turbine cascades are used to verify this method. Results show that, aerodynamic performance of the cascades redesigned is either the same as or better than that of the traditional cascades. The computing time is reduced by more than one order of magnitude compared to a "CFD + optimization algorithm" or "surrogate model + optimization algorithm" method. With the advantages in computing time and intelligence, the proposed novel method shows the possibility of replacing traditional design methods.

The intake port of a CA4DD diesel engine was investigated by a computational fluid dynamics (CFD) numerical simulation to enhance the intake swirl and improve the flow characteristics in the engine. The uniform design method was applied to study the influence of guide vanes with different parameters on the intake process at various valve lifts. Nine guide vane models were established and compared to the base model using CATIA™ 3D CAD software. Numerical simulations were conduct with Xflow software based on the lattice Boltzmann method (LBM). The distributions of the streamlines, vorticity, velocity and turbulent intensity in each cylinder were simulated and analyzed. The results show that the influence of the guide vanes on the swirl ratio was greater than 37%, and the flow coefficient was less than 5% compared to the base model. Scheme 5, H7.5-L50-θ20 (guide vane height of 7.5 mm, length of 50 mm and angle of 20°), provided good performance. The flow characteristics of the optimal guide vane model were verified through a steady flow test. When the guide vane aspect ratio and angle were within the ranges of 3.5-6.9 and 12.2°-20.2°, respectively, the swirl ratio had the best effect at maximum valve lift. This study provides a theoretical basis for improving the performance of dual-intake diesel engines.

Artemisia argyi and Houttuynia cordata Thunb are common herbs in most regions of China. In order to test their composite effect as additives on fish, the effects of their extracts mixture on growth performance, antioxidant activity, serum and hepatic lipid levels, and gut bacteria in juvenile grass carp were evaluated. 180 fish were divided into 9 tanks with 3 replicate tanks per treatment, and fed with a control diet (A0) or one of two treatment diets containing 500 (A1) or 1000 mg/kg (A2) mixture of extracts, with equal mass of A. argyi and H. cordata, for 8 weeks. Water flow rate was 8.0 L/min, and water quality parameters were in normal range. At the end of feeding trial, fish weight gain, feed conversion ratio, and survival rate showed no difference among all groups. Significantly higher catalase (CAT) activity and lower malondialdehyde (MDA) content were observed in A1 and A2 groups. Serum triglyceride content was much lower in the A1 group and total cholesterol was lower in experimental groups compared with the control group. Transmission electron microscopy showed that the hepatic lipid droplets were smaller in the experimental groups. High-throughput sequencing identified 10 predominant phyla from gut samples, and Fusobacteria, Bacteroidetes, and Proteobacteria were the most dominant groups. Compared with the control group, in A1 group operational taxonomic unit (OTU) number, species richness (Chao1, and ACE), and α diversity (Shannon index) were higher, and gut bacteria composition was altered in A1 and A2 groups at phylum and genus levels. These results indicated that the extracts mixture of A. argyi and H. cordata can increase antioxidant activity, lower serum and hepatic lipid levels, and improve gut bacteria composition, which can be used as a green additive for grass carp.

This paper studies the fixed-time synchronization problem of fuzzy stochastic cellular neural networks (FSCNNs) with discrete and distributed delay. Compared with the finite-time synchronization in the existing literature, the fixed-time synchronization of FSCNNs is studied for the first time, and the convergence time obtained does not depend on the upper bound of the initial value of the system. In addition, two kinds of control are designed, one is feedback control and the other is adaptive control. Besides, it is the first time to achieve fixed-time synchronization of FSCNNs via adaptive control. Finally, two numerical examples are also proposed to illustrate the practicability and validity of the results we proposed.

People's demand for the decision-making space of opinion expression is getting higher, and the methods to determine the threshold value of current consensus still remain elusive. To deal with large and diverse information of users and discuss deeply the threshold in social networks, we establish a new consistency model with a new preference structure. In this paper, the Pythagorean fuzzy numbers (PFNs) are introduced into social network group decision-making for the expression of decision-makers' preference (DMs) and the concepts definition of the distance measurements, consensus index, and threshold indifference curves, respectively. In addition, we establish a Pythagorean fuzzy group consensus model with minimum adjustment through determining the setting rule of threshold value before reaching the consensus. Finally, we use the proposed model to solve the selection of square cabin hospitals.

Dry-wet cycles can cause fatigue damage to expansive soil, and various control parameters of the dry-wet cycles (initial moisture content, number of dry-wet cycles, cycle amplitude, etc.) can affect the development of soil damage. Therefore, it is important to study the fatigue damage characteristics of expansive soil under dry-wet cycles of constant amplitude. This paper considers expansive soil from Baise in Guangxi, China, as the research object. Based on tests of the P-wave velocity and low-stress shear strength of expansive soil under 0-6 constant amplitude dry-wet cycles, the attenuation laws for the P-wave velocity were analysed, the damage variable of expansive soil was characterized by P-wave velocity, and the rationality of this damage variable was verified by measuring the low-stress shear strength values of expansive soil specimens. Based on the experimental P-wave velocity results, a nonlinear empirical model of fatigue damage for expansive soil was constructed. The results illustrate that the P-wave velocity of an expansive soil sample decreases nonlinearly with an increasing number of dry-wet cycles and that the damage degree increases nonlinearly with an increasing number of cycles. The P-wave velocity can be successfully used to define a representative damage variable for expansive soil.

Our aim was to analyze the effects of set-up errors on dose distribution in radiotherapy treatment for lung cancer by using kilovoltage cone-beam CT (CBCT).

In this study, we used a Varian IX linear accelerator system to perform CBCT scans of 30 lung cancer patients before radiotherapy. Subsequently, the image was matched with the planned CT, and the left and right (LR), top and bottom (SI), and front and back (AP) directions were set incorrectly. And in the CMS planning system, the center of the plan has been moved to the center of the actual scan. Finally, the dose distribution before the bed-moving is simulated. We want to explore the impact of the planned target volume setting error (PTV), the total tumor volume (GTV), and radiation of normal tissues.

The set-up errors of the LR, SI and AP directions were (-0.20±2.84), (-1.09±5.40), and (-2.61±2.08) mm, respectively. The 5mm error accounted for 97.8%, 73% and 92.6% in the three directions. Statistically significant differences were found in the distribution of 95%PTV dose, the average dose of PTV, 95% GTV dose and the average dose of GTV without bed-moving, compared with the original plan.

In clinical lung cancer radiotherapy, the commonly used setting error is usually less than 5mm, most of which are along the AP direction. In this study, we found that the setting error is related to the patientchr('39')s inherent characteristics and can significantly change the radiation treatment dose in the target area.

Radiation not only kills tumor cells, but also damages other sites. The mechanisms of damage caused by the bystander effect of irradiation in animal models are unclear and the time node is single. In this study, we aimed to investigate the inflammatory response of thymus tissue injury in non-irradiated areas at different times after irradiating rat skin.

Rats were irradiated with an X-ray dose of 38 Gy, and at 15 d after irradiation, when the skin wound was most severe, the pro-inflammatory drug high mobility group box1 (HMGB1) and the anti-inflammatory drug glycyrrhizic acid (GA) were injected intraperitoneally into rats. After irradiation, skin tissues were collected for histology, and thymus tissues were collected for gene and protein testing.

Animal model of skin damage was successfully established. The expression of macrophage (F4/80) increased after irradiation, and F4/80 produced cytokines. Through the flow which was activated by inflammatory factors in the blood, DNA damage and the expression of inflammatory-related cytokines in non-irradiated area of the thymus peaked at 15 d after irradiation. Moreover, HMGB1 treatment increased the expression at 1 d after intraperitoneal injection, and GA solution decreased the expression of inflammatory-related cytokines.

When radiation damages the skin, it can cause damage to other organs through the circulation, and an anti-inflammatory GA solution reduced inflammatory responses, which are required to modify radiation-induced systemic effects with anti-inflammatory drugs or agents that affect pathways that cause bystander instability.