Dosimetric evaluation of different planning strategies for hypofractionated whole-breast irradiation technique.

Purpose.The dose hotspot areas in hypofractionated whole-breast irradiation (WBI) greatly increase the risk of acute skin toxicity because of the anatomical peculiarities of the breast. In this study, we presented several novel planning strategies that integrate multiple sub-planning target volumes (sub-PTVs), field secondary placement, and RapidPlan models for right-sided hypofractionated WBI.Methods.A total of 35 cases of WBI with a dose of 42.5 Gy for PTVs using tangential intensity-modulated radiotherapy (IMRT) were selected. Both PTVs were planned for simultaneous treatment using the original manual multiple sub-PTV plan (OMMP) and the original manual single-PTV plan (OMSP). The manual field secondary placement multiple sub-PTV plan (m-FSMP) with multiple objects on the original PTV and the manual field secondary placement single-objective plan (m-FSSP) were initially planned, which were distribution-based of V105 (volume receiving 105% of the prescription dose). In addition, two RapidPlan-based plans were developed, including the RapidPlan-based multiple sub-PTVs plan (r-FSMP) and the RapidPlan-based single-PTV plan (r-FSSP). Dosimetric parameters of the plans were compared, and V105 was evaluated using multivariate analysis to determine how it was related to the volume of PTV and the interval of lateral beam angles (ILBA).Results.The lowest mean V105 (5.64 ± 6.5%) of PTV was observed in m-FSMP compared to other manual plans. Upon validation, r-FSSP demonstrated superior dosimetric quality for OAR compared to the two other manual planning methods, except for V5(the volume of ipsilateral lung receiving 5 Gy) of the ipsilateral lung. While r-FSMP showed no significant difference (p = 0.06) compared to r-FSSP, it achieved the lowest V105 value (4.3 ± 4.5%), albeit with a slight increase in the dose to some OARs. Multivariate GEE linear regression showed that V105 is significantly correlated with target volume and ILBA.Conclusions.m-FSMP and r-FSMP can substantially enhance the homogeneity index (HI) and reduce V105, thereby minimizing the risk of acute skin toxicities, even though there may be a slight dose compromise for certain OARs.

Plan quality and treatment efficiency assurance of two VMAT optimization for cervical cancer radiotherapy.

To investigate the difference of the fluence map optimization (FMO) and Stochastic platform optimization (SPO) algorithm in a newly-introduced treatment planning system (TPS). METHODS: 34 cervical cancer patients with definitive radiation were retrospectively analyzed. Each patient has four plans: FMO with fixed jaw plans (FMO-FJ) and no fixed jaw plans (FMO-NFJ); SPO with fixed jaw plans (SPO-FJ) and no fixed jaw plans (SPO-NFJ). Dosimetric parameters, Modulation Complexity Score (MCS), Gamma Pass Rate (GPR) and delivery time were analyzed among the four plans. RESULTS: For target coverage, SPO-FJ plans are the best ones (P ≤ 0.00). FMO plans are better than SPO-NFJ plans (P ≤ 0.00). For OARs sparing, SPO-FJ plans are better than FMO plans for mostly OARs (P ≤ 0.04). Additionally, SPO-FJ plans are better than SPO-NFJ plans (P ≤ 0.02), except for rectum V45Gy. Compared to SPO-NFJ plans, the FMO plans delivered less dose to bladder, rectum, colon V40Gy and pelvic bone V40Gy (P ≤ 0.04). Meanwhile, the SPO-NFJ plans showed superiority in MU, delivery time, MCS and GPR in all plans. In terms of delivery time and MCS, the SPO-FJ plans are better than FMO plans. FMO-FJ plans are better than FMO-NFJ plans in delivery efficiency. MCSs are strongly correlated with PCTV length, which are negatively with PCTV length (P ≤ 0.03). The delivery time and MUs of the four plans are strongly correlated (P ≤ 0.02). Comparing plans with fixed or no fixed jaw in two algorithms, no difference was found in FMO plans in target coverage and minor difference in Kidney_L Dmean, Mu and delivery time between PCTV width≤15.5 cm group and >15.5 cm group. For SPO plans, SPO-FJ plans showed more superiority in target coverage and OARs sparing than the SPO-NFJ plans in the two groups. CONCLUSIONS: SPO-FJ plans showed superiority in target coverage and OARs sparing, as well as higher delivery efficiency in the four plans.

An exploratory analysis of MR-guided fractionated stereotactic radiotherapy in patients with brain metastases.

Purpose: To assess the feasibility and potential benefits of online adaptive MR-guided fractionated stereotatic radiotherapy (FSRT) in patients with brain metastases (BMs). Methods and materials: Twenty-eight consecutive patients with BMs were treated with FSRT of 30 Gy in 5 fractions on the 1.5 T MR-Linac. The FSRT fractions employed daily MR scans and the contours were utilized to create each adapted plan. The brain lesions and perilesional edema were delineated on MR images of pre-treatment simulation (Fx0) and all fractions (Fx1, Fx2, Fx3, Fx4 and Fx5) to evaluate the inter-fractional changes. These changes were quantified using absolute/relative volume, Dice similarity coefficient (DSC) and Hausdorff distance (HD) metrics. Planning target volume (PTV) coverage and organ at risk (OAR) constraints were used to compare non-adaptive and adaptive plans. Results: A total of 28 patients with 88 lesions were evaluated, and 23 patients (23/28, 82.1%) had primary lung adenocarcinoma. Significant tumor volume reduction had been found during FSRT compared to Fx0 for all 88 lesions (median -0.75%, -5.33%, -9.32%, -17.96% and -27.73% at Fx1, Fx2, Fx3, Fx4 and Fx5, p < 0.05). There were 47 (47/88, 53.4%) lesions being accompanied by perilesional edema and the inter-fractional changes were significantly different compared to those without perilesional edema (p < 0.001). Patients with multiple lesions (13/28, 46.4%) had more significant inter-fractional tumor changes than those with single lesion (15/28, 53.6%), including tumor volume reduction and anatomical shift (p < 0.001). PTV coverage of non-adaptive plans was below the prescribed coverage in 26/140 fractions (19%), with 12 (9%) failing by more than 10%. All 140 adaptive fractions met prescribed target coverage. The adaptive plans also had lower dose to whole brain than non-adaptive plans (p < 0.001). Conclusions: Significant inter-fractional tumor changes could be found during FSRT in patients with BMs treated on the 1.5 T MR-Linac. Daily MR-guided re-optimization of treatment plans showed dosimetric benefit in patients with perilesional edema or multiple lesions.

Development of a GPU-superposition Monte Carlo code for fast dose calculation in magnetic fields.

Objective.To develop and validate a graphics processing unit (GPU) based superposition Monte Carlo (SMC) code for efficient and accurate dose calculation in magnetic fields.Approach.A series of mono-energy photons ranging from 25 keV to 7.7 MeV were simulated with EGSnrc in a water phantom to generate particle tracks database. SMC physics was extended with charged particle transport in magnetic fields and subsequently programmed on GPU as gSMC. Optimized simulation scheme was designed by combining variance reduction techniques to relieve the thread divergence issue in general GPU-MC codes and improve the calculation efficiency. The gSMC code's dose calculation accuracy and efficiency were assessed through both phantoms and patient cases.Main results.gSMC accurately calculated the dose in various phantoms for bothB = 0 T andB = 1.5 T, and it matched EGSnrc well with a root mean square error of less than 1.0% for the entire depth dose region. Patient cases validation also showed a high dose agreement with EGSnrc with 3D gamma passing rate (2%/2 mm) large than 97% for all tested tumor sites. Combined with photon splitting and particle track repeating techniques, gSMC resolved the thread divergence issue and showed an efficiency gain of 186-304 relative to EGSnrc with 10 CPU threads.Significance.A GPU-superposition Monte Carlo code called gSMC was developed and validated for dose calculation in magnetic fields. The developed code's high calculation accuracy and efficiency make it suitable for dose calculation tasks in online adaptive radiotherapy with MR-LINAC.

Dosimetric Accuracy of MR-Guided Online Adaptive Planning for Nasopharyngeal Carcinoma Radiotherapy on 1.5 T MR-Linac.

Purpose: The aim of this study is to evaluate the dose accuracy of bulk relative electron density (rED) approach for application in 1.5 T MR-Linac and assess the reliability of this approach in the case of online adaptive MR-guided radiotherapy for nasopharyngeal carcinoma (NPC) patients. Methods: Ten NPC patients formerly treated on conventional linac were included in this study, with their original planning CT and MRI collected. For each patient, structures such as the targets, organs at risk, bone, and air regions were delineated on the original CT in the Monaco system (v5.40.02). To simulate the online adaptive workflow, firstly all contours were transferred to MRI from the original CT using rigid registration in the Monaco system. Based on the structures, three different types of synthetic CT (sCT) were generated from MRI using the bulk rED assignment approach: the sCTICRU uses the rED values recommended by ICRU46, the sCTtailor uses the patient-specific mean rED values, and the sCTHomogeneity uses homogeneous water equivalent values. The same treatment plan was calculated on the three sCTs and the original CT. Dose calculation accuracy was investigated in terms of gamma analysis, point dose comparison, and dose volume histogram (DVH) parameters. Results: Good agreement of dose distribution was observed between sCTtailor and the original CT, with a gamma passing rate (3%/3 mm) of 97.81% ± 1.06%, higher than that of sCTICRU (94.27% ± 1.48%, p = 0.005) and sCTHomogeneity (96.50% ± 1.02%, p = 0.005). For stricter criteria 1%/1 mm, gamma passing rates for plans on sCTtailor, sCTICRU, and sCTHomogeneity were 86.79% ± 4.31%, 79.81% ± 3.63%, and 77.56% ± 4.64%, respectively. The mean point dose difference in PTVnx between sCTtailor and planning CT was -0.14% ± 1.44%, much lower than that calculated on sCTICRU (-8.77% ± 2.33%) and sCTHomogeneity (1.65% ± 2.57%), all with p < 0.05. The DVH differences for the plan based on sCTtailor were much smaller than sCTICRU and sCTHomogeneity. Conclusions: The bulk rED-assigned sCT by adopting the patient-specific rED values can achieve a clinically acceptable level of dose calculation accuracy in the presence of a 1.5 T magnetic field, making it suitable for online adaptive MR-guided radiotherapy for NPC patients.

Extension and validation of a GPU-Monte Carlo dose engine gDPM for 1.5 T MR-LINAC online independent dose verification.

PURPOSE: To extend and validate the accuracy and efficiency of a graphics processing unit (GPU)-Monte Carlo dose engine for Elekta Unity 1.5 T Magnetic Resonance-Linear Accelerator (MR-LINAC) online independent dose verification. METHODS: Electron/positron propagation physics in a uniform magnetic field was implemented in a previously developed GPU-Monte Carlo dose engine-gDPM. The dose calculation accuracy in the magnetic field was first evaluated in heterogeneous phantom with EGSnrc. The dose engine was then commissioned to a Unity machine with a virtual two photon-source model and compared with the Monaco treatment planning system. Fifteen patient plans from five tumor sites were included for the quantification of online dose verification accuracy and efficiency. RESULTS: The extended gDPM accurately calculated the dose in a 1.5 T external magnetic field and was well matched with EGSnrc. The relative dose difference along central beam axis was less than 0.5% for the homogeneous region in water-lung phantom. The maximum difference was found at the build-up regions and heterogeneous interfaces, reaching 1.9% and 2.4% for 2 and 6 MeV mono-energy photon beams, respectively. The root mean square errors for depth-dose fall-off region were less than 0.2% for all field sizes and presented a good match between gDPM and Monaco GPUMCD. For in-field profiles, the dose differences were within 1% for cross-plane and in-plane directions for all calculated depths except dmax. For penumbra regions, the distance-to-agreements between two dose profiles were less than 0.1 cm. For patient plan verification, the maximum relative average dose difference was 1.3%. The gamma passing rates with criteria 3% (2 mm) for dose regions above 20% were between 93% and 98%. gDPM can complete the dose calculation for less than 40 s with 5 × 108 photons on a single NVIDIA GTX-1080Ti GPU and achieve a statistical uncertainty of 0.5%-1.1% for all evaluated cases. CONCLUSIONS: A GPU-Monte Carlo package-gDPM was extended and validated for Elekta Unity online plan verification. Its calculation accuracy and efficiency make it suitable for online independent dose verification for MR-LINAC.

Achyrophenols A-F: Polycyclic Polyphenol Lactone Skeletons and a Nor-Ursane-Type Triterpenoid from Achyrocline Satureioides.

Two novel derivatives of 2-methyl-1-(2,3,4,6-tetrahydroxyphenyl)propan-1-one and (S)-2-methyl-1-(2,3,4,6-tetrahydroxyphenyl)butan-1-one (1 and 2), four novel six-membered lactone phenols (3-6), and a nor-ursane type triterpenoid (7) named Achroacid, were isolated from the aerial part of Achyrocline satureioides. The absolute configurations of 1-7 are presented by spectroscopic data and X-ray crystallographic analysis. A DP4plus evaluation was applied to determine the final stereochemistry for 1 and 2. The biosynthesis pathway of 1 and 2 was proposed. 1 has potential on anti-Gram-negative bacteria. Both 1 and 2 exhibited a significant impact on anti-H1299 cells. Compounds 3-7 showed moderate cancer cell lethality and significant anti-inflammatory activities.

Separation and enrichment of sibiskoside from Sibiraea angustat with magnetic surface dummy template molecularly imprinted polymers.

In this work, a novel strategy was developed for separation and enrichment of sibiskoside by dummy molecular imprinting technology and magnetic separation technology. The structural analogue geniposide was selected as the dummy template, using 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as the cross-linking agent, and acetonitrile as the porogen. The molecularly imprinted layer was formed on the surface of the magnetic carrier to prepare dummy template molecularly imprinted polymers (DMIPs) with a core-shell structure. The DMIPs were characterized by scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA) and Vibration sample magnetometer (VSM). The results of adsorption kinetics experiments and isothermal adsorption experiments showed that DMIPs can reach adsorption equilibrium in a short period of time and the maximum adsorption capacity can reach 14.67 mg/g. The imprinting factor was 2.08. Compared with the andrographolide, polydatin, arbutin, caffeic acid, neohesperidin dihydrochalcone and quercetin, DMIPs have good adsorption capacity for the sibiskoside. And the reusability was better. After the adsorption of DMIPs, the purity of sibiskoside in the crude extracts from Sibiraea angustata increased to 78%. It provided a basis for the further development and utilization of Sibiraea angustata as well as the separation and enrichment of monoterpenes.

Correlation of autophagy-related genes for predicting clinical prognosis in colorectal cancer.

Aim: Autophagy plays a controversial role in cancer. The role of autophagy-related genes (ARGs) in colorectal cancer (CRC) was evaluated based on publicly available data from The Cancer Genome Atlas and the Human Autophagy Database. Materials & methods: After collecting CRC-related transcript and clinical data and a list of ARGs from public databases, the Wilcoxon test was used to identify the differentially expressed ARGs between CRC and paired normal tissues. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were used to identify the major biological properties and pathways associated with these genes. Univariate Cox regression was used to identify the prognosis-associated ARGs, and a forest plot was used to visualize the results. Kaplan-Meier analysis of the 5-year survival rate was performed. Univariate and multivariate Cox analyses were used to verify the impact of the prognosis-associated ARGs. Results: A total of 36 differentially expressed genes (16 upregulated and 20 downregulated in CRC) were obtained from among 206 ARGs. There were 53 enriched pathways, including the p53 signaling pathway, platinum drug resistance, apoptosis, EGFR tyrosine kinase inhibitor resistance and ErbB signaling pathway (p- and q-values <0.05). Kaplan-Meier analysis showed that the 5-year survival rate was 46.0% (95% CI: 0.335-0.631) and 76.0% (95% CI: 0.651-0.886) in the high- and low-risk groups, respectively. The high-risk patients had worse survival probability (p = 6.256 × 10-5). Independent-samples t-tests revealed that MAP1LC3C expression was higher in patients aged ≤65 than >65 (p = 0.022); RAB7A expression was higher in patients aged ≤65 than >65 (p = 7.31 × 10-4), higher in M1 than M0 (p = 0.042), higher in N1-3 than N0 (p = 0.002) and higher in stage III and IV than I and II (p = 0.042); risk score was higher in N1-3 than N0 (p = 0.001) and in stage III and IV than I and II (p = 0.002); and WIPI2 expression was higher in M1 than M0 (p = 0.002), higher in N1-3 than N0 (p = 2.059 × 10-7) and higher in stage III and IV than I and II (p = 2.299 × 10-7). There were no differences in risk score between males and females (p = 0.593), T1-2 and T3-4 (p = 0.082) or M0 and M1 (p = 0.072). Univariate and multivariate Cox analyses showed that RAB7A was a lower-risk gene, while MAP1LC3C, WIPI2, DAPK1, ULK3 and PELP1 were high-risk genes. Conclusion: Certain ARGs are potential prognostic molecular markers of poor prognosis in CRC. Additionally, the p53 signaling pathway, platinum drug resistance, apoptosis, EGFR tyrosine kinase inhibitor resistance and ErbB signaling pathway may be critical pathways regulated by ARGs in CRC.

Comparison of Intensity Modulated Radiotherapy Treatment Plans Between 1.5T MR-Linac and Conventional Linac.

In this study, we assess the dosimetric qualities and usability of planning for 1.5 T MR-Linac based intensity modulated radiotherapy (MRL-IMRT) for various clinical sites in comparison with IMRT plans using a conventional linac. In total of 30 patients with disease sites in the brain, esophagus, lung, rectum and vertebra were re-planned retrospectively for simulated MRL-IMRT using the Elekta Unity dedicated treatment planning system (TPS) Monaco (v5.40.01). Currently, the step-and-shoot (ss) is the only delivery technique for IMRT available on Unity. All patients were treated on an Elekta Versa HDTM with IMRT using the dynamic multileaf collimator (dMLC) technique, and the plans were designed using Monaco v5.11. For comparison, the same dMLC-IMRT plan was recalculated with the same machine and TPS but only changing the technique to step-and-shoot. The dosimetric qualities of the MRL-IMRT plans, to be evaluated by the Dose Volume Histograms (DVH) metrics, Homogeneity Index and Conformality Index, were compared with the clinical plans. The planning usability was measured by the optimization time and the number of Monitor Units (MUs). Comparing MRL-IMRT with conventional linac based plans, all created plans were clinically equivalent to current clinical practice. However, MRL-IMRT plans had higher dose to skin and larger low dose region of normal tissues. Furthermore, MRL-IMRT plans had significantly reduced optimization time by comparing conventional linac based plans. The number of MUs of MRL-IMRT was increased by 23% compared with ss-IMRT, and no difference from dMLC-IMRT. In conclusion, clinically acceptable plans can be achieved with 1.5 T MR-Linac system for multiple tumor sites. Given the differences in machine characteristics, some minor differences in plan quality were found between MR-Linac plans and current clinical practice and this should be considered in clinical practice.

Six new anthraquinone glycosides from Lasianthus acuminatissimus Merr.

Six new anthraquinones named lasianthuoside F (1), G (2), H (3), I (4), J (5), K (6) were isolated from an acetone extract of the root of Lasianthus acuminatissimus. Their structures were elucidated by physical and chemical evidence and spectral analysis.

In-Air Electron Streaming Effect for Esophageal Cancer Radiotherapy With a 1.5 T Perpendicular Magnetic Field: A Treatment Planning Study.

PURPOSE: To investigate the in-air out-of-field electron streaming effect (ESE) for esophageal cancer radiotherapy in the presence of 1.5 T perpendicular magnetic field. METHODS: Ten esophageal cancer patients treated with conventional Linac were retrospectively enrolled into a cohort of this study, with the prescription of 4,400 cGy/20 fx. All cases received IMRT replanning using Elekta Unity MR-Linac specified Monaco system, denoted as primary plan. To visualize the in-air dose outside the body in Monaco system, an auxiliary structure was created by extending the external structure. For each case, another comparable plan with no magnetic field was created using the same planning parameters. The plan was also recalculated by placing a bolus upon the neck and chin area to investigate its shielding effect for ESE. Dosimetric evaluations of the out-of-field neck and chin skin area and statistical analysis for these plans were then performed. RESULTS: Out-of-field ESE was also observed in esophageal cancer treatment planning under 1.5 T magnetic field, while totally absent for plans with no magnetic field. On average, the maximum dose to the neck and chin skin area of the primary plan (657.92 ± 69.07 cGy) was higher than that of plan with no magnetic field (281.78 ± 36.59 cGy, p = 0.005) and plan with bolus (398.43 ± 69.19 cGy, p = 0.007). DVH metrics D1cc (the minimum dose to 1 cc volume) of the neck and chin skin for primary plan was 382.06 ± 44.14 cGy, which can be reduced to 212.42 ± 23.65 cGy by using the 1 cm bolus (with p = 0.005), even lower than the plan without magnetic field (214.45 ± 23.82, p = 0.005). No statistically significant difference of the neck and chin skin dose between the plan with bolus and plan with no magnetic field was observed (all with p > 0.05). CONCLUSION: For MRI guided esophageal cancer radiotherapy, a relatively high out-of-field neck and chin skin doses will be introduced by ESE in the presence of magnetic field. It is therefore recommended to take this into account during the planning phase. Adding bolus could effectively reduce the ESE dose contributions, achieve the shielding effect almost equivalent to the scenario with no magnetic field. Further explorations of measurement verifications for the ESE dose distributions are required.

Feasibility of using a commercial collapsed cone dose engine for 1.5T MR-LINAC online independent dose verification.

PURPOSE: To validate the feasibility and accuracy of commonly used collapsed cone (CC) dose engine for Elekta Unity 1.5T MR-LINAC online independent dose verification. MATERIALS AND METHODS: The Unity beam model was built and commissioned in RayStation treatment planning system with CC dose engine. Four AAPM TG-119 test plans were created and measured with ArcCHECK phantom for comparison, another thirty patient plans from six tumor sites were also included. The dosimetric criteria for various ROIs and 3D gamma passing rates were quantitatively evaluated, and the effects of magnetic field and dose deposition type on the dose difference between two systems were further analyzed. RESULTS: ArcCHECK based measurement showed a clear magnetic field induced profile shift between CC with both measurement and GPUMCD. For clinical plans, gamma passing rates with criteria (3%, 3 mm) between GPUMCD and CC large than 90% can be achieved for most tumor sites except esophagus and lung cases, the mean dose difference of 3% can be satisfied for most ROIs from all tumor sites. The magnetic field caused a large dose impact on low density areas, the average gamma passing rates were improved from 85.54% to 96.43% and 87.40% to 99.54% for esophagus and lung cases when the magnetic field effect was excluded. CONCLUSIONS: It is feasible to use CC dose engine as a secondary dose calculation tool for Elekta Unity system for most tumor sites, while the accuracy is limited and should be used carefully for low density areas, such as esophagus and lung cases.

Hierarchical Porous MoS2/C Nanospheres Self-Assembled by Nanosheets with High Electrochemical Energy Storage Performance.

To overcome the deficiency of the volume expansion of MoS2 as the anode material for lithium-ion batteries (LIBs), an effective strategy was developed to design hierarchical porous MoS2/carbon nanospheres via a facile, easy-operated hydrothermal method followed by annealing. FESEM and TEM images clearly showed that nanospheres are composed of ultra-thin MoS2/C nanosheets coated with carbon layer and possess an expanded interlayer spacing of 0.98 nm. As anodes for LIBs, MoS2/carbon nanospheres deliver an initial discharge capacity of 1307.77 mAh g-1 at a current density of 0.1 A g-1. Moreover, a reversible capacity of 612 mAh g-1 was obtained even at 2 A g-1 and a capacity retention of 439 mAh g-1 after 500 cycles at 1 A g-1. The improved electrochemical performance is ascribed to the hierarchical porous structure as well as the intercalation of carbon into lattice spacing of MoS2, which offers fast channels for ion/electron transport, relieves the influence of volume change and increases electrical conductivity of electrode. Meanwhile, the expanded interlayer spacing of MoS2 in MoS2/C can decrease the ion diffusion resistance and alleviate the volumetric expansion during discharge/charge cycles.

Hypolipidemic constituents from the aerial portion of Sibiraea angustata.

Two new monoterpene acylglucosides (1-2) and one new aromatic glycoside (3), together with five known compounds (4-8), were isolated from 95% ethanol extract of Sibiraea angustata. The structures of these compounds were characterized by 2D-NMR and mass spectrometry. Compounds were evaluated for their hypolipidemic activity using oleic acid-induced lipid accumulation in HepG2 cells. RT-PCR analysis revealed that compound 5 could decrease the expression level of fatty acid synthase (FASN). Lipidomics analysis indicated that compound 5 significantly decreased the levels of 11 lipids in oleic acid-induced lipid accumulation, including triglycerides (TG), diglycerides (DG), phosphatidylcholines (PC) and 1-acyl-sn-glycero-3-phosphocholines (lysoPC). These data demonstrated that terpene acylglucosides are the major active constituents in Sibiraea angustata.

A fast robust optimizer for intensity modulated proton therapy using GPU.

Robust optimization has been shown to be effective for stabilizing treatment planning in intensity modulated proton therapy (IMPT), but existing algorithms for the optimization process is time-consuming. This paper describes a fast robust optimization tool that takes advantage of the GPU parallel computing technologies. The new robust optimization model is based on nine boundary dose distributions - two for ±range uncertainties, six for ±set-up uncertainties along anteroposterior (A-P), lateral (R-L) and superior-inferior (S-I) directions, and one for nominal situation. The nine boundary influence matrices were calculated using an in-house finite size pencil beam dose engine, while the conjugate gradient method was applied to minimize the objective function. The proton dose calculation algorithm and the conjugate gradient method were tuned for heterogeneous platforms involving the CPU host and GPU device. Three clinical cases - one head and neck cancer case, one lung cancer case, and one prostate cancer case - were investigated to demonstrate the clinical feasibility of the proposed robust optimizer. Compared with results from Varian Eclipse (version 13.3), the proposed method is found to be conducive to robust treatment planning that is less sensitive to range and setup uncertainties. The three tested cases show that targets can achieve high dose uniformity while organs at risks (OARs) are in better protection against setup and range errors. Based on the CPU + GPU heterogeneous platform, the execution times of the head and neck cancer case and the prostate cancer case are much less than half of Eclipse, while the run time of the lung cancer case is similar to that of Eclipse. The fast robust optimizer developed in this study can improve the reliability of traditional proton treatment planning in a much faster speed, thus making it possible for clinical utility.

A flexible, room-temperature and solution-processible copper nanowire based transparent electrode protected by reduced graphene oxide exhibiting high performance and improved stability.

Advances in flexible electronic and optoelectronic devices have caused higher requirements for fabricating high-performance and low cost flexible transparent conductive electrodes (TCEs). Copper nanowires (Cu NWs) possess excellent electrical and optical properties, but the large contact resistance and poor stability limit their practical application in optoelectronic devices. In this work, we report a robust, convenient and environment-friendly method to assemble copper nanowires/reduced graphene oxide (Cu NWs/rGO) TCEs with enhanced conductivity, flexibility and stability at room temperature. The NaBH4 treatment was used to remove the organics and oxides on the surface of Cu NWs, and the graphene oxide (GO) capping layer was also effectively reduced at the same time. The best Cu NWs/rGO composite TCEs show a good optical-electrical performance with a sheet resistance of ∼50 Ω/sq and transmittance of 83% as well as superior mechanical flexibility. The oxidation resistance of Cu NWs in normal environment and even at a relatively high temperature has also been greatly improved. Additionally, the Cu NWs/rGO TCEs based heaters presented high saturation temperature and rapid response time under a low voltage. The high-performance composite Cu NWs TCEs with good stability are expected to be applied in various types of flexible optoelectronic devices.

ZIF-67-Derived CoSe/NC Composites as Anode Materials for Lithium-Ion Batteries.

As a typical metal selenide, CoSe is a kind of foreground anode material for lithium-ion batteries (LIBs) because of its two-dimensional layer structure, good electrical conductivity, and high theoretical capacity. In this work, the original CoSe/N-doped carbon (CoSe/NC) composites were synthesized using ZIF-67 as a precursor, in which the CoSe nanoparticles are encapsulated in NC nanolayers and they are connected through C-Se bonds. The coating structure and strong chemical coupling make the NC nanolayers could better effectively enhance the lithium storage properties of CoSe/NC composites. As a consequence, the CoSe/NC composites deliver a reversible capacity of 310.11 mAh g-1 after 500 cycles at 1.0 A g-1. Besides, the CoSe/NC composites show a distinct incremental behavior of capacity.

MOF-Derived ZnSe/N-Doped Carbon Composites for Lithium-Ion Batteries with Enhanced Capacity and Cycling Life.

In this work, three different morphologies of ZnSe/N-doped carbon (NC) composites are synthesized using ZIF-8 by a facile calcination process. By adjusting the particle size of precursor ZIF-8, the morphology and size of the product ZnSe/NC can be controlled. The as-prepared ZnSe/NC composites show excellent cyclic stability and rate capability as anode materials in lithium-ion batteries (LIBs). Especially, the as-obtained ZnSe/NC-300 exhibits reversible discharge capacity of 724.4 mAh g-1 after 500 cycles at 1 A g-1. The introduction of N-doped carbon can significantly improve the conductivity of ZnSe and promotes the transfer of electrons. And mesoporous structure is conducive to the penetration of electrolyte in active materials, increases the contact area, and alleviates the volume expansion during the charge-discharge process. Thus, ZnSe/NC composites provide a new insight into the development of anode materials for next-generation high-performance LIBs.

TOPAS Monte Carlo simulation for double scattering proton therapy and dosimetric evaluation.

PURPOSE: To construct and commission a double scattering (DS) proton beam model in TOPAS Monte Carlo (MC) code. Dose comparisons of MC calculations to the measured and treatment planning system (TPS) calculated dose were performed. METHODS: The TOPAS nozzle model was based on the manufacturer blueprints. Nozzle set-up and beam current modulations were calculated using room-specific calibration data. This model was implemented to reproduce pristine peaks, spread-out Bragg peaks (SOBP) and lateral profiles. A stair-shaped target plan in water phantom was calculated and compared to measured data to verify range compensator (RC) modeling. RESULTS: TOPAS calculated pristine peaks agreed well with measurements, with accuracies of 0.03 cm for range R90 and 0.05 cm for distal dose fall-off (DDF). The calculated SOBP range, modulation width and DDF differences between MC calculations and measurements were within 0.05 cm, 0.5 cm and 0.03 cm respectively. MC calculated lateral penumbra agreed well with measured data, with difference less than 0.05 cm. For RC calculation, TPS underestimated the additional depth dose tail due to the nuclear halo effect. Lateral doses by TPS were 10% lower than measurement outside the target, while maximum difference of MC calculation was within 2%. At deeper depths inside the target volume, TPS overestimated doses by up to 25% while TOPAS predicted the dose to within 5% of measurements. CONCLUSION: We have successfully developed and commissioned a MC based DS nozzle model. The performance of dose accuracy by TOPAS was superior to TPS, especially for highly inhomogeneous compensator.