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Multi‐isocenter volumetric modulated arc therapy (VMAT) is recommended for craniospinal irradiation (CSI) to smooth the dose distribution in the junction regions relying solely on inverse optimization. However, few studies have measured the dosimetric impact of setup errors on this multi‐isocenter VMAT in the junction areas. The purpose of this study is to evaluate the impact of positional errors during VMAT CSI with two‐dimension (2D) and three‐dimension (3D) dosimetric measurements. A total of 20 patients treated by three‐isocenter VMAT CSI were retrospectively reviewed and analyzed. A 3D diode array ArcCHECK and radiochromic film EBT3 were applied to measure the percentage gamma passing rates (%GPs) and dose distributions in the junction areas between the cranial/upper‐spinal and the upper/lower‐spinal fields with intentionally introduced setup errors of ± 1 mm, ±2 mm, ±3 mm, ±5 mm, and ± 8 mm, respectively. The length and volume of planning target volume (PTV) for these CSI patients ranged from 50.14 to 80.8 cm, and 1572.3 to 2114.5 cm3, respectively. The %GPs for ±3 mm, ±5 mm, and ±8 mm positional errors were around 95%, 90%, and 85%, respectively, in the junction areas. The dosimetric verification results with EBT3 films indicated that cold and hot areas were observed with the increase of introduced setup errors. In conclusion, the dosimetric verification with intentionally introduced setup errors demonstrated that positional errors within 3 mm have a little impact for VMAT CSI, although setup errors should be minimized. Relying on the inverse optimization of VMAT to smooth the dose distribution in the junction areas is feasible for CSI.

Objective To research and assess automatic volumetric modulated arc therapy (VMAT) planning methods for patients with intraocular cancer. Methods The mdaccAutoPlan system was added to the Pinnacle3 treatment planning system as a plug‐in. Automatic VMAT plans were generated for 10 patients diagnosed with intraocular cancer, and evaluated according to standard dose‐volume histogram parameters. Results The planning target volume of enrolled patients ranges from 14.24 to 50.69 cm3. Both planning methods lead to acceptable planning target volume target coverage with a V95 of 97.9 ± 1.4% and 96.4 ± 1.5% for manual and automatic plans (P = 0.03), respectively. Automatic planning lowered the dose delivered to the ipsilateral lens and optical nerves, but increased the dose to the brainstem compared with manual planning. Automatic planning significantly prolonged VMAT planning time (3.25 ± 0.53 h vs. 1.02 ± 0.69 h, P

Background Controversial conclusions had been reported in studies trying to confirm the impact of heart dose on overall survival (OS) reported in RTOG 0167 for non-small cell lung cancer (NSCLC) patients who underwent radiotherapy (RT). The purpose of this study is to investigate the association of lung and heart dosimetric parameters with OS in NSCLC patients treated by volumetric modulated arc therapy (VMAT). Methods Inoperable NSCLC patients treated by VMAT from March 2012 to December 2015 were retrospectively reviewed. OS and progression-free survival (PFS) were estimated with the Kaplan-Meier method. Univariate and multivariate analyses were conducted with Cox proportional hazards model. Multivariate model building was conducted using stepwise regression for variables with p-value smaller than 0.2 in the univariate analysis. Results There were 130 NSCLC patients enrolled in this study with a median age of 63 years (range from 34 to 82 y). The median prescription dose for these patients was 56 Gy (range 40-70 Gy) with a mean heart and lung dose of 14.8±8.5 Gy and 13.6±4.4 Gy, respectively. The rates of patients with above grade III radiation pneumonitis (RP) and fibrosis were 8.5% and 8.5%, respectively. The 2-year PFS and OS of these patients were 15.2% and 39.8%, with a median PFS and OS of 7.2 and 18.8 months, respectively. RP was correlated with OS (p=0.048) and lung V20 was associated with PFS (p=0.04) according to the univariate analysis. Multivariate analysis demonstrated that RP (HR 1.39, 95%CI 1.010-1.909, p=0.043) and heart V15 (HR 1.02, 95%CI 1.006-1.025 p=0.002) were progression factors of OS, and no factor was associated with PFS. Conclusions RP and heart V15 were associated with OS for patients with stage III NSCLC who underwent VMAT. Heart and lung dosimetric parameters were highly correlated with each other, sparing of heart and lung should be considered equally during the treatment planning.

The impoundment of the Three Gorges Reservoir (TGR), the largest hydropower project in the world, has altered the sediment deposition and erosion regime of downstream-linked rivers and lakes. The extent to which the TGR impoundment has changed the surface areas of the two largest freshwater lakes in China, Lake Dongting and Lake Poyang, remains largely unknown. Here, we compared the surface areas of the two lakes pre and post the TGR impoundment as well as with a modelled non-TGR scenario. We found that the mean surface areas of Lake Dongting and Lake Poyang during the post-TGR period (2003–2016) were significantly smaller than in the pre-TGR period (1956–2002) and in the modelled non-TGR scenario (2003–2016). The impoundment of TGR has led to a shift from a sediment deposition regime to an erosion-dominated regime of the downstream-linked rivers and the two lakes. The impoundment of TGR further changed the seasonal variabilities in discharge and water level in the downstream-linked rivers and the two lakes, especially in the flood season. Our results suggest that TGR resulted in a 5.1%, 16.2%, and 12.2% decrease of the surface area of Lake Dongting in June 2003–September 2006, October 2006–September 2008, and October 2008–December 2016, respectively, and a corresponding decrease of 12.4%, 19.6%, and 15.8% for Lake Poyang. These changes cannot be attributed to variations in rainfall as no significant differences were found in the annual or monthly mean rainfall in the watersheds upstream of Luoshan and Jiujiang + Hukou between the pre-TGR and the post-TGR period. Our results call for the development of a strong holistic management plan for cascading reservoirs, including TGR, to minimize the damage of downstream lake ecosystems.

Background: Published data on the effects and toxicities of volumetric modulated arc therapy (VMAT) in the management of inoperable lung cancer are scarce. Materials and methods: The clinical outcomes and pulmonary toxicities of 134 patients with consecutive inoperable lung cancer who underwent VMAT from March 2011 to September 2016 were retrospectively reviewed. The dosimetric and characteristic factors associated with acute radiation pneumonitis (RP) and pulmonary fibrosis were evaluated with univariate and multivariate analysis. Results: The average prescription doses to these 134 patients were 57.07±6.27 Gy (range 52-64 Gy). The overall median follow-up time was 18.6 months (range, 2-45 mo), with a median follow-up time for the surviving patients of 20 months (range, 7-45 mo). The 2-year progression-free survival (PFS) and overall survival (OS) for all patients were 18.2% and 38.4%, with a median PFS and OS of 7.6 months and 18.6 months, respectively. The percent of patients with grade III/higher RP and pulmonary fibrosis were 10.5% and 9.0%, respectively. V13 (p=0.02) and age (p=0.02) were independently associated with acute RP according to multivariate analysis. The constraints for lung dosimetric metrics V10,V13,V20 and V30 were approximately 49%,41%,26% and 17% in VMAT treatment of lung cancer to limit the RP rate < 10%. Conclusion: VMAT can be delivered safely with acceptable acute and late toxicities for lung cancer patients. Lung dosimetric metrics were valuable in predicting acute RP. A lung V13 constraint of 40% was helpful to limit the RP rate < 10% in VMAT treatment of lung cancer patients.

Induced seismicity might occur during underground energy and resource exploitation. Seismic waves usually attenuate during propagation across rock joints. Joint surface configuration parameters such as the joint roughness coefficient (JRC) and joint matching coefficient (JMC) play an important role in affecting stress wave propagation and dynamic property. An experimental study was conducted by using the modified Split Hopkinson Pressure Bar (SHPB) apparatus to reveal the influence of surface characteristics (i.e., JRC and JMC) on wave propagation quantitatively. The two bars of the SHPB apparatus were fabricated from high-strength gypsum. Each specimen has an artificial joint and consists of two parts produced by 3D printing. The effect of JRC and the combined effect of JRC and JMC on wave propagation and the dynamic mechanical property of joints were analyzed. The incident, transmitted and reflected waves were recorded from the strain gauges. Based on the basic theory of SHPB tests, the transmission coefficients, the stress–strain relationships and the specific stiffness of joints were obtained. According to the test results, both JRC and JMC affect stress wave propagation across joints and the joint specific stiffness to a significant extent. The results show that the transmission coefficient and specific stiffness decrease with increasing JRC (e.g., JMC = 1). In addition, for specimens with a given JRC, the transmission coefficient and specific stiffness decrease with the decrease of JMC.

Background: The existence of liver cancer stem cells (LCSCs) and the occurrence of epithelial-mesenchymal transition (EMT) are generally considered to be the primary causes for migration and metastasis of Hepatocellular carcinoma (HCC). Accumulating evidences demonstrate that tRFs and tiRNAs, are an emerging category of regulatory RNA molecules derived from transfer RNA (tRNA), are dysregulated in in various human cancer types and play crucial roles. However, their impact on tumorigenesis is still in the exploratory stage, their roles and mechanisms in HCC and LCSCs are still unknown.Methods: Quantitative real-time PCR (qRT-PCR) was performed to detect the expression of glycine tRNA-derived fragments (Gly-tRF) in HCC cell lines and tumor tissues. Inhibitor and mimic were performed to weaken and enhance the function of Gly-tRF. Flow cytometry and sphere formation assay to detect the representative surface markers (CD133, CD13, EpCAM, CD44) proportion and stemness of LCSCs. Transwell assay and scratched wound assay were performed to detect HCC cells migration. Western blot was used to detect the expression of EMT-related proteins. Dual luciferase reporter assay and signaling pathway analysis were performed to explore the underlying mechanism of Gly-tRF functions.Results: Gly-tRF is highly expressed in HCC cell lines and tumor tissues, compared to L02 hepatocytes and adjacent normal tissues. Flow cytometry and sphere formation assay found that Gly-tRF mimic promotes LCSCs subpopulation proportion and LCSCs-like cells stemness. Next, functional experiments confirmed that Gly-tRF mimic promotes HCC cells migration and EMT. Consistently, Loss of Gly-tRF inhibits HCC cells migration and EMT. Mechanistically, Gly-tRF inhibits the level of NDFIP2 mRNA by binding to the NDFIP2 3′ UTR. Importantly, overexpression of NDFIP2 can weaken the effect of Gly-tRF in promoting LCSCs-like cells sphere formation and HCC cells migration, NDFIP2 is the direct target of Gly-tRF. Signaling pathway exploration found that Gly-tRF enhances the abundance of phosphorylated AKT.Conclusions: Gly-tRF promotes EMT of HCC cells and enhances LCSCs-like cells stemness via targeting NDFIP2 and activating AKT signaling pathway. The tRNA-derived fragments provide a new perspective of oncology research, and can be the direction of future oncology research.

As a calcium antagonist, the mechanism of nifedipine for treating chilblain has not been reported. In the present study, we established the chilblain model by using -20 ℃ 95% ethanol to freeze the right back foot of SD rats, and investigated the effects of this drug. Hematoxylin-eosin (HE) examination indicated most of pannus in the skin tissue of chilblain rats had disappeared, and the local inflammatory cells were also greatly reduced when given nifedipine at 15.0 mg/kg/d. The enzyme-linked immunosorbent assay (ELISA) revealed that nifedipine inhibited release of inflammatory factors TNF-α, IL-6, IL-1β and VEGF in serum. The RT-PCR analysis showed that nifedipine down regulated mRNA levels of TRPC-6 and VEGF in skin tissue. Furthermore, immunohistochemical examination showed nifedipine inhibited expression of IL-1β, IL-6, and TNF-α inflammatory protein and further inhibited expression of TRP (transient receptor potential) family proteins TRPM-7, TRPC-1, TRPC-3 and TRPC-6 and reduced expression of VEGF in skin and relieved erythema and oedema. This study demonstrated that nifedipine as an old medicine can be new use for the treatment of chilblain by acting on TRPs family and inflammatory proteins.

The aim of this study was to investigate the feasibility and sensitivity of using individual volume-based 3D gamma indices for composite dose-volume histogram (DVH)-based intensity-modulated radiation therapy (IMRT) quality assurance (QA). Composite IMRT QA for 15 cervical cancer patients was performed with ArcCHECK. The percentage dosimetric errors (%DEs) of DVH metrics when comparing treatment planning system and QA-reconstructed dose distribution, percentage gamma passing rates (%GPs) with different criteria for individual volumes and global gamma indices were evaluated, as well as their correlations. Receiver operating characteristic (ROC) curves were applied in order to study the sensitivities of the global and individual volume gamma indices. Most %DEs of the DVH metrics were within 3%. The γPTV and γrectum were

The transmission capacity (TC) of the wireless ad-hoc network is one of the key properties to ensure the quality of network service. The main goal of this study is to explore the mobility of the network to establish a node mobile model with a saturated state and determine the TC and delay for the network based on the bidirectional full-duplex (BFD) system. Considering the outage probability, packet arrival rate, and failure probability of packet attempting transmission, the node mobility models are established based on the node mobility and network self-organization. In analysis, this study determines the mobile state, static state, communication state, and outage stat by defining the mobile rule and range of nodes, then the steady-state probability of each state is obtained by calculating the state transition matrix. After optimising the existing saturated Markov model, the authors determine the network delay and TC based on the mobile nodes, contention window size, maximum number of given packet attempting retransmission, back-off time and signal-interference ratio (SIR) etc. The theoretical analysis and numerical simulation show that the TC of the bidirectional ad-hoc network can be significantly improved by using space resources in two directions, and the introduction of the BFD system is indeed to reduce the network delay.

Purpose: To investigate the feasibility of partial arc volumetric modulated arc therapy (VMAT) in lung cancer stereotactic body radiotherapy (SBRT), as well the volumetric and dosimetric effects of different internal target volume (ITV) definitions with 4D CT. Methods: Fourteen patients with primary and metastatic lung cancer underwent SBRT were enrolled. Full and partial arc VMAT plans were generated with four different ITVs: ITVall, ITVMIP, ITVAIP and ITV2phases, representing ITVs generated from all 10 respiratory phases, maximum intensity projection (MIP), average intensity projection (AIP), and 2 extreme respiratory phases. Volumetric and dosimetric differences, as well as MU and delivery time were investigated. Results: Partial arc VMAT irradiated more dose at 2 cm away from planning target volume (PTV) (P = 0.002), however, it achieved better protection on mean lung dose , lung V5, spinal cord, heart and esophagus compared with full arc VMAT. The average MU and delivery time of partial arc VMAT were 240 and 1.6 min less than those of full arc VMAT. There were no significant differences on target coverage and organ at risks (OARs) sparing among four ITVs. The average percent volume differences of ITVMIP, ITVAIP and ITV2phases to ITVall were 8.6%, 13.4%, and 25.2%, respectively. Conclusions: Although partial arc VMAT delivered more dose 2 cm out of PTV, it decreases the dose to lung, spinal cord, and esophagus, as well decreased the total MU and delivery time compared with full arc VMAT without sacrificing target coverage. Partial arc VMAT was feasible and more efficient for lung SBRT.

Chromophoric dissolved organic matter (CDOM) is crucial in the biogeochemical cycle and carbon cycle of aquatic environments. However, in inland waters, remotely sensed estimates of CDOM remain challenging due to the low optical signal of CDOM and complex optical conditions. Therefore, developing efficient, practical and robust models to estimate CDOM absorption coefficient in inland waters is essential for successful water environment monitoring and management. We examined and improved different machine learning algorithms using extensive CDOM measurements and Landsat 8 images covering different trophic states to develop the robust CDOM estimation model. The algorithms were evaluated via 111 Landsat 8 images and 1708 field measurements covering CDOM light absorption coefficient a(254) from 2.64 to 34.04 m−1. Overall, the four machine learning algorithms achieved more than 70% accuracy for CDOM absorption coefficient estimation. Based on model training, validation and the application on Landsat 8 OLI images, we found that the Gaussian process regression (GPR) had higher stability and estimation accuracy (R2 = 0.74, mean relative error (MRE) = 22.2%) than the other models. The estimation accuracy and MRE were R2 = 0.75 and MRE = 22.5% for backpropagation (BP) neural network, R2 = 0.71 and MRE = 24.4% for random forest regression (RFR) and R2 = 0.71 and MRE = 24.4% for support vector regression (SVR). In contrast, the best three empirical models had estimation accuracies of R2 less than 0.56. The model accuracies applied to Landsat images of Lake Qiandaohu (oligo-mesotrophic state) were better than those of Lake Taihu (eutrophic state) because of the more complex optical conditions in eutrophic lakes. Therefore, machine learning algorithms have great potential for CDOM monitoring in inland waters based on large datasets. Our study demonstrates that machine learning algorithms are available to map CDOM spatial-temporal patterns in inland waters.

Quantitative global assessments of aquatic vegetation dynamics in lakes are lacking despite reports of the losses of submerged aquatic vegetation. We conducted a comprehensive global assessment of aquatic vegetation at 155 study sites. We also included ≥ 2 yr of information on the absolute or relative area of aquatic vegetation from the literature. We calculated the difference between initial and final observed aquatic vegetation area (or cover) to represent the overall trends over time. We classified the study sites of aquatic vegetation into the categories “increasing”, “decreasing” or “no change” using a threshold of 10%. Aquatic vegetation area (or cover) decreased in 101 study sites, particularly in China (35 study sites), increased in 43 study sites, and showed no marked changes in 11 study sites. Our results revealed an accelerating decrease rate (vegetation loss in terms of area or cover) over time: 13.5 ± 16.9%/yr (1900–1980), 21.8 ± 28.9%/yr (1980–2000) and 33.6 ± 59.8%/yr (after 2000). Moreover, the area (or cover) increase rate in lakes where aquatic vegetation showed recovery decreased from 23.5 ± 29.9%/yr (1980–2000) to 16.8 ± 13.2%/yr (after 2000). We conclude that aquatic vegetation loss is accelerating, especially that of submerged aquatic vegetation and particularly in lakes with an area larger than 50 km 2 . The predominance of decreasing vegetation found in our study is likely caused by multiple stressors such as eutrophication, algal blooms, land reclamation, aquaculture cultivation and global climate changes.

Ag nanoparticles (NPs) show a excellent surface plasmon resonance (SPR), which is expected to enable fluorescence enhancement. In this study, a facile approach is proposed for fabrication of Ag NPs/long-wavelength carbon dots (Ag-LCDs) hybrids, wherein Ag NPs work as a fluorescent reinforcer to enhance photoluminescence (PL) intensity of LCDs. The largest enhancement was acquired through adjusting the volume ration between Ag NPs and LCDs. In this process, PL decay is considered as an important and simple characterization to speculate the metal enhanced fluorescence (MEF) mechanism. On the basis of result of small reduction in lifetime, we proposed that the mechanism may be predominantly derived from the localized effectric field effect and partly from the intrinsic radiative decay rate. Moreover, spin-coating technology was utilized to produce LCDs and Ag-LCDs hybrids films. Then, white light-emitting diodes (white LEDs) were constructed by these films with controllable thicknesses and GaN chips. The constructed white LED presented excellent optical performances with an optimal color coordinates (CIE) of (0.33, 0.35), a color rendering index (CRI) of 74.6, a correlated color temperature (CCT) of 5435 K. Notably, the existence of Ag NPs enable these LCDs to improve the luminous efficacy (LE) from 32.63 lm W−1 to 41.26 lm W−1. Such superior optical merits enable them the promising potentials for application in optical devices.

Although gamma analysis is still a widely accepted quantitative tool to analyze and report patient‐specific QA for intensity‐modulated radiotherapy (IMRT) and volumetric‐modulated arc therapy (VMAT), the correlation between the 2D percentage gamma passing rate (%GP), and the clinical dosimetric difference for IMRT and VMAT has been questioned. The purpose of this study was to investigate the feasibility of individual volume‐based 3D gamma indices for pretreatment VMAT QA. Percentage dosimetric errors (%DE) of dose‐volume histogram metrics (includes target volumes and organ at risks) between the treatment planning system and QA‐reconstructed dose distribution, %GPs for individual volume and global gamma indices, as well their correlations and sensitivities were investigated for one‐ and two‐arc VMAT plans. The %GPs of individual volumes had a higher percent of correlation with individual 15 %DE metrics compared with global %GPs. For two‐arc VMAT at 2%/2 mm, 3%/3 mm, and 4%/4 mm criteria, individual volume %GPs were correlated with 9, 12, and 9 out of 15 %DE metrics, while global %GPs were correlated with only 2 out of 15 %DE metrics, respectively. For one‐arc VMAT at 2%/2 mm, 3%/3 mm, and 4%/4 mm criteria, individual volume %GPs were correlated with 18, 16, and 13 out of 23 %DE metrics, and global %GPs were correlated with 19, 12, and 1 out 23 %DE metrics, respectively. The area under curves (AUC) of individual volume %GPs were higher than those of global %GPs for two‐arc VMAT plans, but with mixed results for one‐arc VMAT plans. In a conclusion, the idea of individual volume %GP was created and investigated to better serve for VMAT QA and individual volume‐based %GP had a higher percent of correlation with DVH 15 %DE metrics compared with global %GP for both one‐ and two‐arc VMAT plans.

BackgroundThe aim of this study was to evaluate toxicity, compliance, recurrence and the survival of weekly and triweekly cisplatin-based concomitant chemoradiation in treatment of cervical cancer.Materials and MethodsThe databases were searched from 1995 until 2015 to identify eligible studies on weekly versus triweekly cisplatin chemoradiotherapy. The data were analyzed by RevMan 5.3 software.ResultsA total of 5 randomized controlled trials were included in this review. Weekly cisplatin regimen significantly reduced the incidence of Hematologic toxicity. However, there was no significantly different between the 2 arms in compliance, recurrence and the survival rate (allP>0.05).ConclusionsWeekly cisplatin regimen had the similar therapeutic effect as the triweekly cisplatin regimen but with less hematologic toxicity. Therefore, we recommend the weekly cisplatin 30 to 40 mg/m2chemoradiotherapy as the strong candidate for the optimal cisplatin dose and dosing schedule in the treatment of locally advanced cervical cancer.

Herein, we present a facile approach to produce long-wavelength emitting carbon dots (CDs). A shift of the fluorescence emission wavelength of CDs from 630 nm to 520 nm can be easily acquired. The as-synthesized CDs exhibit concentration-dependent PL property as well as the “solvatochromism” phenomenon, which are rarely known in CDs. As the concentration or solvent polarity of the CDs increases, the photoluminescence (PL) wavelength exhibits a red shift. More importantly, the QY of these long-wavelength CDs is as high as 52.4%, which is considerably higher than that mentioned in other reports. Moreover, on addition of an acid (HCl), the surface H+-functionalization on the CDs leads to strong quenching of fluorescence emission, which is almost reversible after the addition of a strong base (NaOH). Then, CDs based solid-state composites were fabricated using a combination of polyvinyl butyral (PVB) and CDs. Finally, CDs/PVB composites were deposited on the Ce3+:Y3Al5O12 (Ce3+:YAG) phosphor-in-glass (Ce-PiG) via a screen-printing technology. Warm white light-emitting diodes (WLEDs) were then fabricated using these materials and GaN chips. The results indicate that these CDs possess a potential for future applications in warm WLEDs.

This paper firstly analyzes the transmission mechanism of the wireless broadband multi-media services in the MSW-ARQ(Multi-channel Stop-and-Wait ARQ) system. Considering the real-time multimedia service's four features (high requirement for delay but allows some loss rate, the constraints of the delay and jitter), in order to meet with professional standard, we model the real-time multimedia service packet transmission as an M[X]/G/1 queuing model for MSW-ARQ. The packet transition probability is derived by constructing steady state Markov Chain based on the method of selecting the reference packet. On the basis of equivalent service delay, we also solve the packet mean service delay. Then under the given condition, we analyze the influence of the channel number and channel environments on the mean delay through numerical simulating. The characteristics and superiorities of multi-channel transmission mechanism in wireless communication are checked enough by solving the M[X]/G/1 queuing model. So this paper provides useful thought and approach for optimizing system delay and throughput by checking the change of channel environments and the used number of parallel channels.

Purpose: The purpose of the present study was first to apply the progressive optimization algorithm based automatic volumetric modulated arc therapy (POA-VMAT) technology to accelerate and improve the radiotherapy of cervicothoracic esophageal cancer (CTEC). We comprehensive analyze the feasibility, normal tissue complication probability (NTCP) and dosimetric results of POA-VMAT, manual based VMAT and step-shoot intensity-modulated radiation therapy (IMRT) plans in the treatment of CTEC. Methods: Sixty patients with CTEC with or without concomitant chemotherapy at our institution between 2017 and 2019 were retrospectively identified. The manual 7field-IMRT (7f-IMRT), Single-arc-VMAT and Double-arc-VMAT (Single-Arc/Double-Arc) plans were generated in all cases. The POA-VMAT was designed using the automatic dual-arc VMAT technology of Pinnacle3 9.10 planning system based on progressive optimization algorithm. Specially, it includes the selection of treatment techniques, the running of automated planning scripts, and the evaluation of the final radiotherapy regimen. Subsequently, quantitative evaluation of plans was performed by means of standard dose–volume histograms, homogeneity index (HI) and conformity index (CI). Results: Target dose conformity of the 7f-IMRT plan was inferior to all plans, whereas the Double-Arc plan was slightly inferior to the POA-VMAT but superior to the Single-Arc and 7f-IMRT plan. The HI for 7f-IMRT, Single-Arc, Double-Arc and POA-VMAT were 0.17 ± 0.08, 0.28 ± 0.06, 0.29 ± 0.06 and 0.28 ± 0.03, respectively. For the NTCP results, there was significant statistical difference among POA-VMAT, IMRT and VMAT plans. The total MU was reduced by 48.3% and 42.1% in Single-Arc and POA-VMAT plans compare to IMRT plans. Conclusions: By comprehensive consideration, POA-VMAT efficiently generate acceptable treatment plans for CTEC without dose escalation to OARs and overall superior to manual planning which is a good option for treating CTEC.

With the development of biosensors and wireless technology, the early wearable medical devices have been far from meeting the demands of human, and the mobile medical care has recently gained the increasing attention. The wireless body sensor network (WBSN) has made a significant contribution to the non-invasive collection of human physiological signals. This paper aims at the collection of four vital signs of the human body in WBSN, different priorities are given to four vital signs and the queuing model of different priority data that collected at patient's wireless device (named PDA) is analyzed. Meanwhile, this paper notices that the problem of network congestion in WBSN, the network environment of data transmission is divided by the learning results from mote using learning automata. In order to control network congestion, dropping packets of PDA is guided by mote under different network environment and the system delay after dropping packets at PDA is analyzed. Results in this paper show that “learning” at mote can significantly reduce system delay.

To investigate the treatment response prediction feasibility and accuracy of an integrated model combining computed tomography (CT) radiomic features and dosimetric parameters for patients with esophageal cancer (EC) who underwent concurrent chemoradiation (CRT) using machine learning. The radiomic features and dosimetric parameters of 94 EC patients were extracted and modeled using Support Vector Classification (SVM) and Extreme Gradient Boosting algorithm (XGBoost). The 94-sample dataset was randomly divided into a 70-sample training subset and a 24-sample independent test set while keeping the class proportions intact via stratification. A receiver operating characteristic (ROC) curve was used to assess the performance of models using radiomic features alone and using combined radiomic features and dosimetric parameters. A total of 42 radiomic features and 18 dosimetric parameters plus the patients’ characteristic parameters were extracted for these 94 cases (58 responders and 36 non-responders). XGBoost plus principal component analysis (PCA) achieved an accuracy and area under the curve of 0.708 and 0.541, respectively, for models with radiomic features combined with dosimetric parameters, and 0.689 and 0.479, respectively, for radiomic features alone. Image features of GlobalMean X.333.1, Coarseness, Skewness, and GlobalStd contributed most to the model. The dosimetric parameters of gross tumor volume (GTV) homogeneity index (HI), Cord Dmax, Prescription dose, Heart-Dmean, and Heart-V50 also had a strong contribution to the model. The model with radiomic features combined with dosimetric parameters is promising and outperforms that with radiomic features alone in predicting the treatment response of patients with EC who underwent CRT. • The model with radiomic features combined with dosimetric parameters is promising in predicting the treatment response of patients with EC who underwent CRT. • The model with radiomic features combined with dosimetric parameters (prediction accuracy of 0.708 and AUC of 0.689) outperforms that with radiomic features alone (best prediction accuracy of 0.625 and AUC of 0.412). • The image features of GlobalMean X.333.1, Coarseness, Skewness, and GlobalStd contributed most to the treatment response prediction model. The dosimetric parameters of GTV HI, Cord Dmax, Prescription dose, Heart-Dmean, and Heart-V50 also had a strong contribution to the model.

The dual-hop truncated ARQ (DHT-ARQ) and multiple relays cooperative truncated ARQ (MRCT-ARQ) with relay selection in wireless sensor networks are analytically analyzed in this paper. A three-state discrete time Markov chain method is proposed, which is then used to derive the steady state distribution and throughput expressions. Furthermore, the number of retransmission of the two protocols is truncated, and the average packet transmission delay is solved. Finally, considering the power consumptions of source node, relay node and destination node, the energy efficiency expressions are obtained. Numerical simulation results show that the throughput and delay performance of the latter is better than the former. When the channel environment becomes poor, using the DHT-ARQ protocol is more advantageous to reduce system overhead.

Summary Large deformations and discontinuous problems can be calculated using the discontinuous deformation analysis (DDA) method by solving time steps, and this method is suitable for simulating the seismic dynamic response of engineering rock mass structures. However, the boundary setting must be carefully analyzed. In this paper, four boundary settings for the DDA method are investigated. First, the contributions to the DDA equations for nonreflecting boundaries (including the viscous boundary and the viscoelastic boundary) are deduced based on the Newmark method. Second, a free-field boundary is introduced in the DDA method with boundary grid generation and coupling calculation algorithms to accurately simulate external source wave motion, such as earthquakes. Third, seismic input boundary treatments are intensively examined, and the force input method is introduced based on nonreflecting boundaries. Finally, the static-dynamic unified boundary is implemented to ensure consistent boundary transformation. The boundary setting method in the DDA method is discussed, and the suggested treatments are used to analyze the seismic dynamic response of underground caverns. Copyright © 2015 John Wiley & Sons, Ltd.

Objective The purpose of this study is to investigate the dosimetric advantages of volumetric modulated arc therapy (VMAT) in the treatment of intraocular cancer by comparing it directly with three-dimensional conformal radiotherapy (CRT) and intensity-modulated radiotherapy (IMRT). Methods CRT plan, 7f-IMRT plan, and one-arc VMAT plan were generated for 14 intraocular cancer patients. Dosimetric and biological quality indices for target volume and organs at risks (OARs) were evaluated and compared. Results The target coverage presented by V95 for CRT, IMRT and VMAT were 95.02% ± 0.67%, 95.51% ± 2.25%, and 95.92% ± 3.05%, respectively. The homogeneity index (HI) for CRT, IMRT and VMAT were 0.15 ± 0.05, 0.23 ± 0.05, and 0.23 ± 0.06, respectively. IMRT and VMAT greatly decreased the dose to ipsilateral lens compared with CRT with a D1 of 2972.66 ± 1407.12 cGy, 3317.82 ± 915.28 cGy and 4809.54 ± 524.60 cGy for IMRT, VMAT and CRT, respectively. Similar results were observed for ipsilateral eyeballs. IMRT and VMAT also spared better on brainstem, optical nerves and optical chiasm compared CRT. However, CRT achieved lower dose to the eyeballs compared with IMRT and VMAT. VMAT and IMRT showed mixed results on target coverage and OAR sparing. The average MUs and delivery time of IMRT and VMAT were 531.25 ± 81.21 vs. 400.99 ± 61.49 and 5.05 ± 0.53 vs.1.71 ± 0.69 min, respectively. Conclusions Although no clear distinction on PTV coverage among CRT, IMRT and VMAT plans was observed in the treatment of intraocular cancer, VMAT and IMRT achieved better homogeneity and conformity for target volume, and delivered fewer doses to ipsilateral lens and eyeballs compared with CRT. However, VMAT and IMRT increased the low dose volume to the contralateral OARs. Although VMAT and IMRT showed mixed results on target coverage and OAR sparing, VMAT decreased MU and delivery time significantly compared with IMRT. VMAT is a promising and feasible external beam radiotherapy technique in the treatment of intraocular cancer patients.

Dynamic myocardial perfusion CT (DMP-CT) imaging provides quantitative functional information for diagnosis and risk stratification of coronary artery disease by calculating myocardial perfusion hemodynamic parameter (MPHP) maps. However, the level of radiation delivered by dynamic sequential scan protocol can be potentially high. The purpose of this work is to develop a pre-contrast normal-dose scan induced structure tensor total variation regularization based on the penalized weighted least-squares (PWLS) criteria to improve the image quality of DMP-CT with a low-mAs CT acquisition. For simplicity, the present approach was termed as 'PWLS-ndiSTV'. Specifically, the ndiSTV regularization takes into account the spatial-temporal structure information of DMP-CT data and further exploits the higher order derivatives of the objective images to enhance denoising performance. Subsequently, an effective optimization algorithm based on the split-Bregman approach was adopted to minimize the associative objective function. Evaluations with modified dynamic XCAT phantom and preclinical porcine datasets have demonstrated that the proposed PWLS-ndiSTV approach can achieve promising gains over other existing approaches in terms of noise-induced artifacts mitigation, edge details preservation, and accurate MPHP maps calculation.

This study aims to evaluate the effectiveness and clinical performance of a panel of urinary biomarkers to diagnose prostate cancer (PCa) in Chinese men with PSA levels between 4 and 10 ng/mL. A total of 122 patients with PSA levels between 4 and 10 ng/mL who underwent consecutive prostate biopsy at three hospitals in China were recruited. First-catch urine samples were collected after an attentive prostate massage. Urinary mRNA levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR). The predictive accuracy of these biomarkers and prediction models was assessed by the area under the curve (AUC) of the receiver-operating characteristic (ROC) curve. The diagnostic accuracy of PCA3, PSGR, and MALAT-1 was superior to that of PSA. PCA3 performed best, with an AUC of 0.734 (95% CI: 0.641, 0.828) followed by MALAT-1 with an AUC of 0.727 (95% CI: 0.625, 0.829) and PSGR with an AUC of 0.666 (95% CI: 0.575, 0.749). The diagnostic panel with age, prostate volume, % fPSA, PCA3 score, PSGR score, and MALAT-1 score yielded an AUC of 0.857 (95% CI: 0.780, 0.933). At a threshold probability of 20%, 47.2% of unnecessary biopsies may be avoided whereas only 6.2% of PCa cases may be missed. This urinary panel may improve the current diagnostic modality in Chinese men with PSA levels between 4 and 10 ng/mL.

This paper presents a new Amplify-and-Forward Cooperative Automatic Repeat reQuest protocol with channel state information-assisted relay which is more suitable for the only-read access networks. The channels of any pair of terminations are quasi static flat Nakagami- $$m$$ m fading channels, which are mutually independent and non-identically distributed. Assuming that the coherent equal gain combining is adopted to combine the retransmitted signals from the same link at the destination and selective combining is adopted to the signals from different links. Based on the approximation of product of Nakagami- $$m$$ m variables, we obtain the end-to-end signal-to-noise rate of any link. The closed-form expression of the average bit error rate for several modulation schemes is obtained by analyzing cumulative distribution function (CDF) and Gaussian Q-function. Then we analyze the amount of fading of the fading channels by the $$n$$ n order moment which is obtained by CDF. Numerical simulation results show that the relay node can resist the fading of system effectively comparing with the system without relay node. And with the increasing of the number of transmission, the performance advantage of relay link is more and more obviously. It is better to let the maximum transmission time $$F=6$$ F = 6 , which is very useful for improving the transmission efficiency of the truncated ARQ system. The maximum reduction of amount of fading can be reached when $$t=3$$ t = 3 , if the total number of transmission is $$f=6$$ f = 6 . The number of bits in the frame should not have too big.

A new plan quality index integrating dosimetric and radiobiological indices was proposed to facilitate the evaluation and comparison of simultaneous integrated boost (SIB) intensity modulated radiotherapy (IMRT) plans for nasopharyngeal cancer (NPC) patients. Ten NPC patients treated by SIB-IMRT were enrolled in the study. Custom software was developed to read dose-volume histogram (DVH) curves from the treatment planning system (TPS). A plan filtering matrix was introduced to filter plans that fail to satisfy treatment protocol. Target plan quality indices and organ at risk (OAR) plan quality indices were calculated for qualified plans. A unique composite plan quality index (CPQI) was proposed based on the relative weight of these indices to evaluate and compare competing plans. Plan ranking results were compared with detailed statistical analysis, radiation oncology quality system (ROQS) scoring results and physician's evaluation results to verify the accuracy of this new plan quality index. The average CPQI values for plans with OAR priority of low, normal, high, and PTV only were 0.22 ± 0.08, 0.49 ± 0.077, 0.71 ± 0.062, and -0.21 ± 0.16, respectively. There were significant differences among these plan quality indices (One-way ANOVA test, p < 0.01). This was consistent with statistical analysis, ROQS results and physician's ranking results in which 90% OAR high plans were selected. Plan filtering matrix was able to speed up the plan evaluation process. The new matrix plan quality index CPQI showed good consistence with physician ranking results. It is a promising index for NPC SIB-IMRT plan evaluation.

Radiation-associated toxicities due to sophisticated ocular anatomy and shape variability of organs at risk (OARs) are major concerns during external beam radiation therapy (EBRT) of patients with intraocular cancer. A novel two-step image registration strategy between optical coherence tomography (OCT) and computed tomography (CT) images was proposed and validated to precisely localize the target in the EBRT of patients with intraocular cancer. Specifically, multiple features from OCT and CT images were extracted automatically, then spatial transformation based on thin-plate spline function was performed iteratively to achieve feature alignment between the CT and OCT images. Finally, an exclusive OR (XOR) algorithm was applied for precise 3D registration using a 3D-mesh model generated from OCT and CT volumes. The accuracy of the proposed novel registration strategy was validated and tested in a schematic-eye phantom with an artificially introduced tumor and in ten patients with confirmed primary and/or secondary intraocular cancer. There was an average registration error and computational time of 0.21 ± 0.05° and 259 ± 5 s, together with an average Dice similarity coefficient and Hausdorff distance of 88.4 ± 0.65 and 0.89 ± 0.09, respectively. The preliminary experimental results demonstrated that the proposed novel strategy to overcome current limitations on eye modeling and to localize precisely the tumor target during EBRT of intraocular cancer is promising.

To study the feasibility of using volumetric-modulated arc therapy (VMAT) to deliver whole-field simultaneous integrated boost (WF-SIB) to treat patients with nasopharyngeal cancer (NPC). WF-SIB intensity-modulated radiotherapy (IMRT) plans, one-arc WF-SIB VMAT plans, and two-arc WF-SIB VMAT plans were generated with identical objective functions for 8 patients with NPC of various stages. Isodose distributions and dose-volume histograms were evaluated. Dosimetric and biological quality indices of clinical target volume (CTV) and organs at risk (OARs) were calculated to study the optimization capability of these 3 modalities in the treatment of patients with NPC. The optimization time, delivery time, required monitor units (MUs), and delivery accuracy were also compared to investigate the feasibility of these 3 modalities. There was no significant difference (p = 0.92) in target coverage (TC) between WF-SIB IMRT (99.00 ± 0.79) and two-arc WF-SIB VMAT (97.98 ± 1.29). However, both had higher TC than one-arc VMAT plans (89.92 ± 6.32, p < 0.01). IMRT demonstrated the best protection of the spinal cord, whereas two-arc VMAT showed the minimum Dmax to OARs. No other significant differences were observed among these 3 modalities on CTV coverage and OAR sparing. The delivery and MU efficiency of one-arc and two-arc WF-SIB VMAT were greatly improved compared with WF-SIB IMRT. The optimization time of one-arc and two-arc WF-SIB VMAT plans were 5 and 10 times greater than that of WF-SIB IMRT, respectively. The delivery accuracy of WF-SIB VMAT was not affected by the increased freedom. For patients with NPC, one-arc WF-SIB VMAT might not be able to achieve sufficient TC, whereas two-arc WF-SIB VMAT was able to achieve reasonable TC. No significant advantage on OAR protection was demonstrated by VMAT compared with IMRT. WF-SIB VMAT has significantly shorter delivery times, but WF-SIB IMRT may still be the first treatment choice for patients with NPC.

Selective-Repeat ARQ (Automatic Repeat reQuest) protocol is the most efficient error control technology in wireless because it allows the transmitter to retransmit only negatively acknowledges (NACK) packets. In this paper, by analyzing the transmission mechanism of SR-ARQ, the discrete-time Geom/G/1/ queue model is established sententiously based on equivalent delay under the condition that the numbers of packets entering the transmitter are assumed to be independent and identically distributed random variables. With the method of embedded Markov chain, the expression formulations of the packet mean waiting delay, system mean delay and channel utilization are explicitly obtained. And then, the sliding window length control model is built adaptively according to the change of transmission conditions. Furthermore, the influences of packet length, the successful transmission probability and packet arrival rate on system mean delay are analyzed by numerical simulation. The numerical simulation results show that the expression formulations are valid for SR-ARQ protocol.

The purpose of this study is to investigate the potential benefits of conformal radiotherapy (CRT) combined with a sequential volumetric‐modulated arc therapy (VMAT) boost in the treatment of upper thoracic esophageal cancer. Ten patients with upper thoracic esophageal cancer previously treated with CRT plus a sequential VMAT boost plan were replanned with CRT plus an off‐cord CRT boost plan and a full course of VMAT plan. Dosimetric parameters were compared. Results indicated that CRT plus off‐cord CRT boost was inferior in planning target volume (PTV) coverage, as indicated by the volume covered by 93% (p = 0.05) and 95% (p = 0.02) of the prescription dose. The full course VMAT plan was superior in conformal index (CI) and conformation number (CN), and produced the highest protection for the spinal cord. CRT plus a VMAT boost demonstrated significant advantages in decreasing the volume of the lung irradiated by a dose of 10 Gy (V10, p = 0.007),13 Gy (V13, p = 0.003), and 20 Gy (V20, p = 0.001). The full course VMAT plan demonstrated the lowest volume of lung receiving a dose of 30 Gy. CRT plus a VMAT boost for upper thoracic esophageal cancer can improve the target coverage and reduce the volume of lung irradiated by an intermediate dose. This combination may be a promising treatment technique for patients with upper thoracic esophageal cancer. PACS number: 87.53.Kn, 87.55.x, 87.55.D, 87.55.dk

Astilbin is a flavonoid compound isolated from the rhizome of Smilax china L. The effects and possible mechanisms of astilbin on hyperuricemia and nephropathy rats were elucidated in this study. Different dosages of astilbin (1.25, 2.5, and 5.0 mg/kg) were administered to 10 % fructose-induced hyperuricemic rats. The results demonstrated that astilbin significantly decreased the serum uric acid (Sur) level by increasing the urinary uric acid (Uur) level and fractional excretion of urate (FEUA) but not inhibiting the xanthine oxidase (XOD) activity. In addition, kidney function parameters such as serum creatinine (Scr) and blood urea nitrogen (BUN) were recovered in astilbin-treated hyperuricemic rats. Further investigation indicated that astilbin prevented the renal damage against the expression of transforming growth factor- β1 (TGF-β1) and connective tissue growth factor (CTGF) and also exerted a renal protective role by inhibiting formation of monosodium urate (MSU) and production of prostaglandin E₂ (PGE₂) and interleukin-1 (IL-1). These findings provide potent evidence for astilbin as a safe and promising lead compound in the development of a disease-modifying drug to prevent hyperuricemia and nephropathy.

Background and purpose Anatomic changing frequently occurred during fractionated radiotherapy. The aims of this study were to model the potential benefit of adaptive IMRT replanning during fractionated radiotherapy and its potential advantage over clinical outcome in patients with nasopharyngeal carcinoma. Materials and methods Thirty-three patients with repeat CT imaging and replanning were retrospectively analyzed. 66 case-matched control patients without replanning were identified by matching for AJCC stage, gender, and age. Hybrid IMRT plans were generated to evaluate the dosimetric changing. Mann–Whitney–Wilcoxon tests were used to evaluate the effect of replanning on volumetric and dosimetric outcomes within individuals. Kaplan–Meier estimators were used to estimate the survival function of patients with or without replanning. Results The mean volume of the ipsilateral and contralateral parotid glands decreased during the treatment. The hybrid IMRT plans showed decreased doses to target volumes and increased doses to normal structures in replanning. The clinical outcome comparison indicated that the IMRT replanning improved the 3years local progression–free survival for patients who had AJCC staged more than T 3 (T 3,4 N x ) and ease the late effects for patients who had large lymph nodes (AJCC stage T x N 2,3 ). Conclusion Repeat CT imaging and IMRT replanning were recommendatory for specific nasopharyngeal carcinoma patients.

Photo-thermal conversion is an effective method to utilise solar energy. The generated heat can be converted into electrical energy through the thermoelectric Seebeck effect. However, the key challenge in enhancing solar-thermal-electric conversion is to achieve efficient photo-thermal conversion and temperature difference control. Herein, new composite materials are prepared using abundant and cheap raw materials to simultaneously realise photo-thermal conversion, heat storage, and heat supply for a thermoelectric device. The composites consist of carbonised waste cotton and stearic acid (SA), where carbonised waste cotton can achieve efficient full spectrum photo-thermal conversion and SA can store the generated heat to maintain a stable temperature for a thermoelectric device. The best content of SA is found to be 85 wt-% in the composites due to uniform dispersion and ideal combination. The 3D netlike structure of carbonised waste cotton provides increased heat transfer paths and also prevents leakage of SA during phase change. The maximum phase change enthalpy is 203.6 J g−1 for the composite with 85 wt-% SA, which is almost the same as pure SA, assuring high density heat storage. A light-thermal-electric conversion device is further constructed based on as-prepared composites and a thermoelectric system. The generated electricity can light up a light-emitting diode with strong intensity.

To investigate comparatively the percentage gamma passing rate (%GP) of two-dimensional (2D) and three-dimensional (3D) pre-treatment volumetric modulated arc therapy (VMAT) dosimetric verification and their correlation and sensitivity with percentage dosimetric errors (%DE).%GP of 2D and 3D pre-treatment VMAT quality assurance (QA) with different acceptance criteria was obtained by ArcCHECK® (Sun Nuclear Corporation, Melbourne, FL) for 20 patients with nasopharyngeal cancer (NPC) and 20 patients with oesophageal cancer. %DE were calculated from planned dose-volume histogram (DVH) and patients' predicted DVH calculated by 3DVH® software (Sun Nuclear Corporation). Correlation and sensitivity between %GP and %DE were investigated using Pearson's correlation coefficient (r) and receiver operating characteristics (ROCs).Relatively higher %DE on some DVH-based metrics were observed for both patients with NPC and oesophageal cancer. Except for 2%/2 mm criterion, the average %GPs for all patients undergoing VMAT were acceptable with average rates of 97.11% ± 1.54% and 97.39% ± 1.37% for 2D and 3D 3%/3 mm criteria, respectively. The number of correlations for 3D was higher than that for 2D (21 vs 8). However, the general correlation was still poor for all the analysed metrics (9 out of 26 for 3D 3%/3 mm criterion). The average area under the curve (AUC) of ROCs was 0.66 ± 0.12 and 0.71 ± 0.21 for 2D and 3D evaluations, respectively.There is a lack of correlation between %GP and %DE for both 2D and 3D pre-treatment VMAT dosimetric evaluation. DVH-based dose metrics evaluation obtained from 3DVH will provide more useful analysis.Correlation and sensitivity of %GP with %DE for VMAT QA were studied for the first time.

Purpose To investigate the feasibility of constant dose rate volumetric modulated arc therapy (CDR-VMAT) in the treatment of nasopharyngeal cancer (NPC) patients and to introduce rotational arc radiotherapy for linacs incapable of dose rate variation. Materials and methods Twelve NPC patients with various stages treated previously using variable dose rate (VDR) VMAT were enrolled in this study. CDR-VMAT, VDR-VMAT and mutlicriteria optimization (MCO) VMAT plans were generated for each patient on RayStation treatment planning system with identical objective functions and the dosimetric differences among these three planning schemes were evaluated and compared. Non dosimetric parameters of optimization time, delivery time and delivery accuracy were also evaluated. Results The planning target volume of clinical target volume (PTV-CTV) coverage of CDR-VMAT was a bit inferior to those of VDR- and MCO-VMAT. The V93 (p = 0.01) and V95 (percent volume covered by isodose line) (p = 0.04) for CDR-VMAT, VDR-VMAT and MCO-VMAT were 98.74% ± 0.31%, 99.76% ± 0.16%, 99.38% ± 0.43%, and 98.40% ± 0.48%, 99.53% ± 0.28%, 99.07% ± 0.52%, respectively. However, the CDR-VMAT showed a better dose homogeneity index (HI) (p = 0.01) in PTV-CTV. No significant difference in other target coverage parameters was observed. There was no significant difference in OAR sparing among these three planning schemes except for a higher maximum dose (Dmax) on the brainstem for CDR-VMAT. The brainstem Dmax of CDR-VMAT, VDR-VMAT and MCO-VMAT were 54.26 ± 3.21 Gy, 52.19 ± 1.65 Gy, and 52.79 ± 4.77 Gy, respectively. The average delivery time (p

Objective To investigate the anatomic and dosimetric variations of volumetric modulated arc therapy (VMAT) in the treatment of nasopharyngeal cancer (NPC) patients based on weekly cone beam CT (CBCT). Materials and methods Ten NPC patients treated by VMAT with weekly CBCT for setup corrections were reviewed retrospectively. Deformed volumes of targets and organs at risk (OARs) in the CBCT were compared with those in the planning CT. Delivered doses were recalculated based on weekly CBCT and compared with the planned doses. Results No significant volumetric changes on targets, brainstem, and spinal cord were observed. The average volumes of right and left parotid measured from the fifth CBCT were about 4.4 and 4.5 cm3 less than those from the first CBCT, respectively. There were no significant dose differences between average planned and delivered doses for targets, brainstem and spinal cord. For right parotid, the delivered mean dose was 10.5 cGy higher (p = 0.004) than the planned value per fraction, and the V26 and V32 increased by 7.5% (p = 0.002) and 7.4% (p = 0.01), respectively. For the left parotid, the D50 (dose to the 50% volume) was 8.8 cGy higher (p = 0.03) than the planned values per fraction, and the V26 increased by 8.8% (p = 0.002). Conclusion Weekly CBCTs were applied directly to study the continuous volume changes and resulting dosimetric variations of targets and OARs for NPC patients undergoing VMAT. Significant volumetric and dosimetric variations were observed for parotids. Replanning after 30 Gy will benefit the protection on parotids.

Detailed transmission electron microscopic study has been carried out on heteroepitaxial YBa2Cu3O7/SrTiO3/YBa2Cu3O7 trilayer thin films grown on (100)SrTiO3 substrates prepared by DC and RF magnetron sputtering. The microstructural results showed the existence of somea-axis-oriented YBCO grains 20–90 nm wide in thec-axis-oriented YBCO matrix. Some of thea-axis grains in the lower YBCO thin film layer have protruded into the above SrTiO3 layer, which may cause short circuit between the two YBCO superconducting layers. This is unsuitable for the application of trilayer thin films for microelectronic devices. The defects on the surface of the substrates would also influence the growth quality of the YBCO thin films.

A SiGe HBT low-noise amplifier (LNA) for UWB application is presented. According to the analysis for noise of common base transistor, noise canceling structure for SiGe HBT is proposed to reduce the noise arising from common transistor, thus reduce the noise of LNA. Meanwhile it also compensate the gain of the LNA, thus improves the gain flatness. The chip layout has been designed, its area is 0.56×0.53 mm2. The simulation results of the LNA demonstrate that in the range of UWB, the noise figure is reduced 2 dB compared with the case without noise canceling, the gain is 16.4∼17.4, gain flatness is ±0.5dB, linearity is •6dBm.

An RF LDMOS high power amplifier operating at WCDMA downlink frequency of 2140 MHz for base station application is presented. The quiescent operating point was determined by DC simulation and then the corresponding simple and practical bias circuit composed of 1/4λ microstrip lines and bypass capacitors was designed. A load-pull simulation method was used to obtain the optimal input and output impedances of the LDMOS transistor, and the matching networks were designed by means of microstrip lines and parallel capacitors. The simulation results show that the output power at 1dB compression (P 1dB ) is 53.58 dBm (230 W), the maximum power added efficiency (PAE) and power gain are 60.86% and 19.27 dB respectively. The IMD3 is less than −36dBc with a 2-tone test at the output power of 47.58dBm.

Galanthamine hydrobromide (GH) has been approved for symptomatic treatment of Alzheimer's disease (AD) and vascular dementia. Hence, the effects of intranasal administration of GH loaded flexible liposomes have been investigated for the first time on the efficiency of acetylcholinesterase inhibition, as well as the pharmacokinetic behavior of GH in rat brain. The GH loaded flexible liposomes were characterized for shape, entrapment capacity, size distribution and zeta potential by transmission electron microscopy (TEM), ultracentrifugation and dynamic light scattering (DLS), respectively. The inhibition of acetylcholinesterase was investigated using rat brain homogenates as an enzyme resource and microdialysis was used to determine the pharmacokinetic behavior of GH in rats brain. The rat pheochromocytoma PC-12 cell line was used to evaluate the cytotoxicity of GH loaded flexible liposomes. The results revealed that: (i) the efficiency of acetylcholinesterase inhibition of GH was greatly enhanced by intranasal administration compared with oral administration, especially GH loaded in flexible liposomes; (ii) the C(max) and AUC(0→10) for intranasal administration of GH loaded flexible liposomes were 3.52 and 3.36 times higher than those of orally administered GH, moreover, the T(max) was greatly shortened from 1.5h for oral administration to 0.75h for intranasal administration of GH loaded flexible liposomes; and (iii) PC-12 cells viability tests showed that the flexible liposome carrier is not toxic to the cultured cells and the cytotoxicity of GH to cells was clearly decreased by loading in flexible liposomes. These results indicate that intranasal administration of GH loaded flexible liposomes could readily transport GH into brain tissues, suggesting some promise for this approach in successful brain-drug targeting in AD treatment.

In this paper, based on small signal models of hetero-junction bipolar transistors (HBTs) with different feedback circuits, the expressions for S parameters of the device are derived to analyze the influence of different feedback technologies on amplifier performance, especially on the stability and the gain flatness of Ultra-Wideband Low Noise Amplifier(UWB LNA). When a serial inductor or a parallel capacitor is added into the feedback circuits to induce reactive feedback, the amplitude of S 21 increases as the frequency increases, the HBT's gain inherent decreasing at high frequency is compensated, a good stability performance can also be reached simultaneously. Based on reactive feedback techniques, we design a 3GHz–10GHz UWB LNA. The simulation results show that throughout the whole frequency band, the amplifier remains unconditionally stable, has a high transmission gain, good gain flatness and low noise figure.

Background To investigate the feasibility and benefits of a modified adaptive radiotherapy (ART) by replanning in the initial CT (iCT) with new contours from a repeat CT (rCT) based on CT-CT image fusion for nasopharyngeal cancer (NPC) patients underwent volumetric modulated arc radiotherapy (VMAT). Materials and methods Nine NPC patients underwent VMAT treatment with a rCT at 23rd fraction were enrolled in this study. Dosimetric differences for replanning VMAT plans in the iCT and in the rCT were compared. Volumetric and dosimetric changes of gross tumor volume (GTV) and organs at risk (OARs) of this modified ART were also investigated. Results No dosimetric differences between replanning in the iCT and in the rCT were observed. The average volume of GTV decreased from 78.83 ± 38.42 cm3 in the iCT to 71.44 ± 37.46 cm3 in the rCT, but with no significant difference (p = 0.42).The average volume of the left and right parotid decreased from 19.91 ± 4.89 cm3 and 21.58 ± 6.16 cm3 in the iCT to 11.80 ± 2.79 cm3 and 13.29 ± 4.17 cm3 in the rCT (both p GTV and PTVCTV coverage were observed for replanning with this modified ART. Compared to the initial plans, the average mean dose of the left and right parotid after re-optimization were decreased by 62.5 cGy (p = 0.05) and 67.3 cGy (p = 0.02), respectively, and the V5 (the volume receiving 5 Gy) of the left and right parotids were decreased by 7.8% (p = 0.01) and 11.2% (p = 0.001), respectively. There was no significant difference on the dose delivered to other OARs. Conclusion Patients with NPC undergoing VMAT have significant anatomic and dosimetric changes to parotids. Repeat CT as an anatomic changes reference and re-optimization in the iCT based on CT-CT image fusion was accurate enough to identify the volume changes and to ensure safe dose to parotids.